- Information
- AI Chat
Cchmlecfinals - Lecture notes
Clinical Chemistry 2 (MDT 3122L)
Our Lady of Fatima University
Recommended for you
Preview text
OUR LADY OF FATIMA UNIVERSITY I PAMPANGA CAMPUS I COLLEGE OF MEDICAL LABORATORY SCIENCE I CLIN CHEMISTRY 1
WEEK 13: THYROID and PARATHYROID HORMONE
CLINICAL CHEMISTRY 2 LECTURE: FINALS Rmt THYROID GLAND ➢ Butterfly-shaped gland ➢ The two lobes are connected by a narrow band (isthmus) ➢ Located at the anterior and lower portion of the neck; found below the larynx/voice box ➢ During the 11 th week of fetal development, the thyroid gland is starting to produce its thyroid hormone ➢ Congenital hypothyroidism / Cretinism ➢ He’s an 18yrs old guy, but his appearance looks like 5yrs old → deficiency in thyroid hormone affects physical development, that is why it is important for the physical and mental development FOLLICLE ➢ Fundamental structural unit of the thyroid gland ➢ 2 TYPES OF CELLS IN THE THYROID GLAND ✓ Follicular Cells – secretes thyroid hormone (T3 and T4) ✓ Parafollicular or (C cells) – Secretes calcitonin
THYROGLOBULIN
➢ Acts as a preformed matrix containing tyrosyl groups; glycoprotein stored in follicular colloid of the thyroid gland ➢ Function: acts as a substrate for the synthesis of the thyroid hormone (T3 & T4); and serves as a storage of the inactive thyroid hormones and iodine BIOSYNTHESIS OF THYROID HORMONES ➢ Iodine is the most important element in the biosynthesis of thyroid hormones ✓ Present in seafoods, dairy, iodized salt, multivitamins ➢ Recommended Daily Intake – 150 micrograms ✓ <50: deficiency of production of the thyroid hormone ➢ The activity of thyroid hormone is DEPENDENT on the location and number of iodine atoms ➢ Iodination of tyrosine residues in thyroglobulin results in formation of first by-product of thyroid hormone synthesis → monoiodotyrosine (MIT) and diiodotyrosine (DIT) IODOTHYRONINE 5-DEIODINASE ➢ This enzyme is very important for the activation and also inactivation of the enzyme ➢ Its action is to convert T4 into T3 (basically, T3 came from the T4 through the process of deiodination where iodine element is being removed from the T4) TYPE 1 IODOTHYRONINE 5-DEIODINASE ➢ MOST ABUNDANT FORM ➢ found mostly in the liver and kidneys ➢ responsible for largest contribution of circulating T3 pool. TYPE 2 IODOTHYRONINE 5-DEIODINASE ➢ found in the brain and pituitary gland ➢ maintain constant levels of T3 in the CNS. ➢ Its activity is decreased when levels of circulating T4 are high and increased when T4 levels are low. THYROID HORMONES BINDING PROTEINS (THBP) ➢ Pertains to transporters of the thyroid hormone THYROXINE-BINDING GLOBULIN (TBG) ➢ Transports 70 %- 75 % of total T ➢ Transports MAJORITY of T3 (affinity weaker than T4) THYROXINE-BINDING PREALBUMIN (TBP) ➢ also known as “Transthyretin” ➢ Transports 15 - 20% of total T ➢ T3 has a very weak or sometimes has no affinity for prealbumin → DO NOT TRANSPORT T THYROXINE-BINDING ALBUMIN (TBA) ➢ Transports the remaining/minor T ➢ Transports 10% of T ➢ MORE PROTEIN and THBP, INCREASED TT3 AND TT
OUR LADY OF FATIMA UNIVERSITY I PAMPANGA CAMPUS I COLLEGE OF MEDICAL LABORATORY SCIENCE I CLIN CHEMISTRY 2
BIOSYNTHESIS OF THYROID HORMONES
➢ Conversion of T4 to T3 takes place in many tissues, particularly the liver and the kidney, pituitary and CNS ➢ Free Hormones (FT3 and FT4) ✓ physiologically active portions of the thyroid hormones → the ones who exert actions ➢ Protein bound hormones ✓ function as storage site for circulating thyroid hormones → metabolically inactive, inert, they do not enter cells ➢ The hypothalamic-pituitary-thyroid axis ✓ is the neuroendocrine system that REGULATES the production and secretion of the thyroid hormones ✓ the hypothalamus releases TRH → TRH, it stimulates the pituitary to release the TSH → TSH will stimulate the thyroid gland to secrete the thyroid hormones (T3 &T4) ➢ Iodine intake BELOW 50 microgram/day = DEFICIENCY of hormone secretion ➢ Thyroid hormones AFFECT synthesis (anabolism), degradation (catabolism), intermediate metabolism of adipose tissue and circulating lipids FUNCTIONS OF THYROID HORMONES ➢ For tissue growth and CNS development ➢ Elevated heat production high levels of thyroid hormone (hyperthyroid) → sensitivity to heat and excessive sweating ➢ Control of oxygen consumption ➢ It influences carbohydrate and protein metabolism ➢ For energy conservation MAJOR THYROID HORMONES TRIIDOTHYRONINE (T3) ➢ MOST ACTIVE THYROID HORMONE ➢ It came from the T4 thru the process of deionization ➢ 75 - 80% is produced from tissue deiodination of T ➢ BETTER INDICATOR of recovery from hyperthyroidism as well as the recurrence of hyperthyroidism ➢ Thyrotoxicosis → main affected thyroid hormone is the T ➢ An increase in the plasma level is the FIRST ABNORMALITY SEEN in cases of hyperthyroidism ➢ Reference values: ✓ 80 to 200 ng/dL or 1 to 3 nmol/L (ADULTS) ✓ 105 to 245 ng/dL or 1 to 3 nmol/L (CHILDREN) TETRAIODOTHYRONINE (T4) / THYROXINE ➢ 2 ND MAJOR THYROID HORMONE ➢ MAJOR FRACTION of ORGANIC IODINE in the circulation ➢ PRINCIPAL SECRETORY PRODUCT of the thyroid gland ➢ All circulating T4 originates from the thyroid gland ➢ The amount of serum T4 is a GOOD INDICATOR of thyroid secretory rate ➢ Elevated thyroxine causes INHIBITION of TSH secretion, and vice versa → because the purpose of TSH is to stimulate the thyroid gland to release thyroid hormones, as a result, if the thyroid hormone is increased, TSH is not required (negative feedback) ➢ Reference values: ✓ 5 to 12 ug/dL or 71 to 161 nmol/L (ADULTS) ✓ 11 to 22 ug/dL or 152 to 292 nmol/L (NEONATES) THYROID AUTOANTIGENS ➢ May cause destruction to thyroid gland affecting its function ➢ Responsible for autoimmune thyroid disorders ✓ Thyroid Peroxidase/ TPO ✓ Thyroglobulin ✓ TSH Receptor
CLINICAL DISORDERS
➢ 2 Major Disorders 1. Hyperthyroidism: excess thyroid hormones in circulation 2. Hypothyroidism: decreased number HYPERTHYROIDISM ➢ Thyrotoxicosis more on T ➢ Grave’s Disease (Diffuse Toxic Goiter) ➢ Riedel’s Thyroiditis ➢ Subclinical Hyperthyroidism ➢ Subacute granulomatous/ Subacute ➢ Nonsuppurative Thyroiditis/ De ➢ Quervain’s Thyroiditis (painful thyroiditis) SIGNS AND SYMPTOMS OF HYPERTHYROIDISM ➢ Tachycardia→ increased pumping/beating of the heart ➢ Tremors→ panginginig ➢ Weight loss → fast metabolism ➢ Heat intolerance, Emotional Lability, Menstrual Changes ➢ one thing that is noticeable, is the bulging of the eye “Exophthalmos” PRIMARY HYPERTHYROIDISM ➢ The organ that releases the hormone is the one that is affected → thyroid is affected ➢ Elevated T3 and T4, Decreased TSH and TRH SECONDARY HYPERTHYROIDISM ➢ The affected organ is the pituitary gland ➢ Increased TSH and FT ➢ due to the primary lesion in the pituitary gland T3 THYROTOXICOSIS / PLUMMER’S DISEASE ➢ Applied to group of syndromes caused by high levels of free thyroid hormones (T3) in circulation → will suppress the TSH ➢ TSH is low, FT4 is normal, Increased FT ➢ primarily affects T ➢ Signs: Tachycardia, Tremor, Warm, moist, flushed, smooth skin, lid lag, widened palpebral fissures, ophthalmopathy (Grave’s disease), Goiter, Brisk deep tendon reflexes, muscle wasting and weakness, Dermopathy/pretibial myexedema (Graves’ disease), Osteopenia, osteoporosis ➢ Symptoms: Nervousness, Irritability, anxiety, tremor, palpitations, fatigue, weakness, decreased exercise tolerance, weight loss, heat intolerance, hyperdefecation, menstrual changes (oligomenorrhea), prominence of eyes
OUR LADY OF FATIMA UNIVERSITY I PAMPANGA CAMPUS I COLLEGE OF MEDICAL LABORATORY SCIENCE I CLIN CHEMISTRY 4
2. TSH TEST
➢ MOST CLINICALLY SENSITIVE ASSAY for the detection of primary thyroid disorders ➢ MOST IMPORTANT THYROID FUNCTION TEST and BEST SCREENING TEST ➢ Helps in the EARLY DETECTION of hypothyroidism (increased TSH) ➢ Used to DIFFERENTIATE primary from secondary hypothyroidism ➢ Used to MONITOR AND ADJUST thyroid hormone replacement therapy ✓ Overdosed thyroid hormone → suppressed TSH ➢ The sensitivity of the third generation TSH assays has led to the ability to detect what is termed subclinical disease- or a mild degree of thyroid dysfunction → can detect even the smallest discrepancy into the concentration of the thyroid hormones ➢ Reference values: 0 to 5 μU/Ml SECOND-GENERATION TSH IMMUNOMETRIC ASSAYS ➢ with detection limits of 0 mU/L ➢ SCREEN for hyperthyroidism THIRD-GENERATION TSH CHEMILUMINOMETRIC ASSAYS ➢ with detection limits of 0 mU/L, ➢ DIFFERENTIATE euthyroidism and hyperthyroidism ➢ routinely used to monitor and ADJUST thyroid hormone replacement therapy ➢ SCREEN BOTH hyperthyroidism and hypothyroidism INCREASED TSH DECREASED TSH Primary Hypothyroidism Primary Hyperthyroidism Hashimoto’s Thyroiditis Secondary and tertiary hypothyroidism Thyrotoxicosis due to pituitary Tumor Treated Grave’s Disease TSH Antibodies Euthyroid Sick Disease Thyroid Hormone Resistance Over Replacement Hormone in Hypothyroidism 3. RADIOACTIVE IODINE UPTAKE (RAIU) ➢ Used to MEASURE THE ABILITY of the thyroid gland to trap iodine ➢ Helpful in ESTABLISHING CAUSE of hyperthyroidism ➢ High uptake indicates metabolically active (active hormone production) ➢ High uptake + TSH deficiency = autonomous thyroid activity → indicates presence of malignancy 4. THYROGLOBULIN ASSAY ➢ Thyroglobulin is a tumor marker for Medullary Thyroid Carcinoma/MTC ➢ Normally used as post-operative marker of thyroid cancer ✓ Because if the thyroglobulin is still detected to the blood → indication that there is remaining malignant cell in patient ➢ Used in MONITORING THE COURSE of metastatic or recurrence of thyroid cancer ➢ When measuring thyroglobulin as a tumor marker for thyroid cancer, ALWAYS CHECK A SIMULTANEOUS SAMPLE for thyroglobulin antibodies ➢ Increased Levels: Untreated and metastatic differentiated thyroid cancer, hyperthyroidism ➢ Decreased Levels: Infants with goiterous hypothyroidism, thyrotoxicosis factitia ➢ Reference Values: ✓ 3 to 42 ng/mL or ug/mL (ADULTS) ✓ 38 to 48 ng/mL or ug/mL (INFANTS) ➢ Methods ✓ Double antibody RIA, ELISA, IRMA, ICMA 5. REVERSE T3 (rT3) ➢ Used to ASSESS borderline or conflicting results ➢ Identifies patient with euthyroid sick syndrome → the thyroid hormone ____ with a non-thyroidal systemic illness (there are other diseases affecting level of thyroid hormone) ➢ rT3 is formed by removal of one iodine from the inner ring of T4 and end product of T4 metabolism ➢ Reference values: 38 to 44 ng/dL 6. FREE THYROXINE INDEX ➢ Also known as 𝐅𝐓𝟒𝐈 or 𝐓𝟕 (it is a test and not a form of thyroid hormone) ➢ INDIRECTLY ASSESS the level of free T4 in theblood ➢ Based on equilibrium relationship of bound T4 and FT ➢ IMPORTANT IN CORRECTING euthyroid individuals ➢ Elevated in hyperthyroidism and Decreased in hypothyroidism ➢ Reference method: equilibrium dialysis ➢ Reference values: 1 to 4. ➢ FT4I = TT4 x T3U (%) or TT4 x THBR 100 7. TOTAL T3 (TT3), FT3 AND FT ➢ 𝐅𝐓𝟒 test is used to DIFFERENTIATE drug induced TSH elevation and hypothyroidism ➢ The value of TT3 or FT3 is in CONFIRMING THE DIAGNOSIS of hyperthyroidism ➢ Direct/reference method: Equilibrium dialysis (FT4) 8. T3 UPTAKE TEST ➢ MEASURES THE NUMBER of available binding sites of the thyroxine-binding proteins,most notably TBG ➢ Elevated TBG results to decrease T3 uptake vice versa ➢ It DOES NOT MEASURE the level of thyroid hormones in serum; REFLECTS TBG LEVELS (major transporter of T3) ➢ A known amount of radiolabeled T3 (TBG) is ADDED TO THE TEST SERUM ➢ estrogen increases TBG while androgen depresses TBG ➢ Increased level: Hyperthyroidism, euthyroid patient, chronic liver disease ➢ Decreased levels: Hypothyroidism, oral contraceptives, pregnancy and acute hepatitis ➢ Reference Values: 25 - 35% 9. THYROXINE BINDING GLOBULIN (TBG) TEST ➢ Specific for TBG, because T3 uptake test also reflects the ability of other thyroid hormone binding protein to bind w/ T ➢ Used to CONFIRM RESULTS of FT3 or FT4 or abnormalities in the relationship of the total thyroxine (TT4) and THBR test ➢ Useful to DISTINGUISH BETWEEN hyperthyroidism causing high thyroxine levels and euthyroidism with increased binding by TBG and increased T ➢ Total Serum T3 and T4 are DEPENDENT ON THE AMOUNT of TBG ➢ Increased levels: Hypothyroidism (it signifies the need for the thyroid hormone), pregnancy, estrogen ➢ Decreased levels: Anabolic steroids, nephrosis
OUR LADY OF FATIMA UNIVERSITY I PAMPANGA CAMPUS I COLLEGE OF MEDICAL LABORATORY SCIENCE I CLIN CHEMISTRY 5
10. FINE NEEDLE ASPIRATION
➢ MOST ACCURATE TOOL in the evaluation of thyroid or hot nodules (possible malignant tumors in thyroid) 11. RECOMBINANT HUMAN TSH ➢ Used to test patients with thyroid cancer for the presence of residual or recurrent disease 12. TANNED ERYTHROCYTE HEMAGGLUTINATION METHOD ➢ Test for antithyroglobulin antibodies for detection of autoantibodies 13. SERUM CALCITONIN TEST ➢ Tumor marker for DETECTING residual thyroid metastasis in MTC/Medullary thyroid carcinoma SUMMARY OF THYROID DISORDERS AND LAB TEST DISEASES T3 T4 TSH FT4 rT3 Tg TBG Grave’s disease
I I D I I I N
Primary hypothyroidism
D /
N
D I D D D /
N
N
Hashimoto thyroiditis
D /
N
D /
N
I D /
N
D D /
N
N
Nonthyroidal illness
D D /
N
v v I / N N Thyroid hormone resistance
I I I / N I I I N
PARATHYROID GLAND
➢ It is located on or near the thyroid capsule (region of the thyroid gland); sometimes within the thyroid gland ➢ Basically found at the back of the thyroid gland ➢ For most of the individuals they have 4 parathyroid glands but others have 8 or 2 ➢ SMALLEST endocrine gland in the body ➢ Secretes parathyroid hormone (PTH – hypercalcemic agent to promote constant level of calcium in our circulation) ROLE OF PARATHYROID HORMONE ➢ INDIRECTLY STIMULATES intestinal absorption of Calcium to maintain the constant level of calcium ➢ As calcium level increases, PTH secretion is suppressed allowing URINARY LOSS OF CALCIUM and CALCIUM TO REMAIN IN BONE ➢ Parathyroid hormones promote the demineralization of the bone (calcium is being taken out of the bones) ➢ If calcium level decreases, PTH is increased
CLINICAL DISORDERS
1. HYPERPARATHYROIDISM
PRIMARY HYPERPARATHYROIDISM
➢ Due to presence of a functioning parathyroid adenoma ➢ Is accompanied with phosphaturia ➢ If it GOES UNDETECTED, severe demineralization may occur which may result to osteitis fibrosa cystica → majority of calcium from bone is released into the circulation ➢ Lab Results: PTH and Ionized Ca increased, Hypercalciuria, Hypophosphatemia (fasting state) SECONDARY HYPERPARATHYROIDISM ➢ Develops in RESPONSE to decrease serum calcium ➢ There is diffuse hyperplasia of all 4 glands ➢ The patient develops severe bone disease ➢ Causes: vit. D deficiency (Vit. D is very important for the absorption of calcium in the intestines) and chronic renal failure (Even Ca, which should be preserved, is secreted.) ➢ Lab results: PTH increased, Ionized calcium decreased TERTIARY HYPERPARATHYROIDISM ➢ It occurs with secondary hyperparathyroidism ➢ Develops autonomous function of the hyperplastic parathyroid glands or of parathyroid adenoma ➢ The phosphate levels are normal to high; Calcium phosphates precipitates in soft tissues 2. HYPORPARATHYROIDISM ➢ Is due to accidental injury to the parathyroid glands (neck) during surgery- postsurgical cause ➢ Other cause: autoimmune parathyroid destruction ➢ Individual are unable to maintain calcium concentration in the blood without calcium supplementation ➢ PTH normally interferes with bicarbonate reabsoption in the PCT;therefore ➢ Low PTH = elevated bicarbonate reabsorption- alkalosis ➢ The BEST METHOD for PTH measurement involves the use of antibodies that DETECT BOTH the amino terminal fragment and intact PTH
CCHM321A(LEC) 2
⮚ Has an anti-inflammatory effect and immunosuppressive property that is why it is used as therapeutic agent ⮚ Therapeutic agent for Rheumatoid Arthritis, Systemic Lupus Erythematosus, Multiple Sclerosis (autoimmune diseases) ⮚ SECRETION is diurnal (highest at 8 - 9am and lowest at 10pm-12am) 🡪 affected by the sleep-wake cycle ⮚ Diurnal hormones must be measured at their highest peak ⮚ Cortisol also maintains the normal blood pressue ⮚ Cortisol is produced from the ZONA FASCICULATA ⮚ Thru the stimulation of the ACTH that’s the time the cortisol is released ⮚ Function: to maintain the blood pressure and glucose homeostasis ⮚ POSSIBLE CAUSES OF LOW CORTISOL 1. None to minimal cortisol stimulation (adrenal gland is stimulated by pituitary and hypothalamus to produce the cortisol 🡪 what happen is that they don’t release hormones that stimulates the adrenal gland to produce the cortisol) ✔ Pituitary releases the ACTH ✔ Hypothalamus releases the CRH 2. Normal cortisol stimulation ✔ Low cortisol even if there’s a normal cortisol stimulation ✔ Pituitary and hypothalamus are in normal state ✔ Low cortisol is due to the problem of the cortex in the adrenal gland; doesn’t function well ⮚ Primary adrenal insufficiency ✔ Affects the adrenal gland ✔ Low cortisol because of the problem of the in the adrenal gland 🡪 pituitary will respond by releasing more ACTH ✔ Low aldo ✔ Hyperpigmentation ⮚ Secondary adrenal insufficiency ✔ Problem either to the pituitary of hypothalamus ✔ Low ACTH, Aldo normal CORTISOL ⮚ Serum, plasma, saliva and urine may be used, blood samples should be drawn during 8-9am (highest level of cortisol) ⮚ Urine free cortisol levels are sensitive indicators of adrenal hyperfunction (endogenous corticolism) URINARY METABOLITES
- 17 - hydroxycorticosteroid ⮚ Measured by Porter-Silber Method ⮚ Reagents: Phenylhydrazine in H2SO4 + alcohol ⮚ Will yield yellow color
- 17 - ketogenic steroids ⮚ Measured by Zimmermann Reaction (reddish purple) ⮚ Reagent: Meta-dinitrobenzene ⮚ Oxidation Procedure: Norymberski (Na bismuthate) CLINICAL DISORDERS
- Hypercortisolism
- Hypocortisolism ⮚ Primary Hypocortisolism ⮚ Secondary Hypocortisolism
- Congenital Adrenal Hyperplasia (like the version of cretinism) ⮚ 21 - hydroxylase deficiency ⮚ 11ß-hydroxylase deficiency ⮚ 3ß-hydroxysteroid dehydrogenase isomerase deficiency ⮚ C-17,20-lyase/ 17α-hydroxilase deficiency HYPERCORTICOLISM CUSHING’S SYNDROME ⮚ Increased cortisol and an elevation in ACTH ⮚ Caused by overuse of corticosteroid and also elevation in ACTH Signs & Symptoms ⮚ Weight gain but with thin extremities (main body is the only part that gains weight🡪particularly around the midsection and upper back, in the face (moon face), and between the shoulders (buffalo hump) ) ,hyperglycemia, thinning of the skin, poor wound healing,hypertension, hypercholesterolemia, decreased WBC Screening Test ⮚ 24 hour urinary free cortisol (inc >120 ug/day) ⮚ Overnight dexamethasone suppression test (result is cortisol is not suppresed) ● Dexamethasone’s action is to suppress the cortisol as well as the ACTH PROCEDURE OF OVERNIGHT / RAPIDDEXAMETHASONE SUPPRESSION TEST ✔ 1 mg of dexamethasone is orally given to patient between 11pm to 12 midnight ✔ Blood is collected the following day 8 am to 9am and urine may be tested for 17 OHCS
CCHM321A(LEC) 3
✔ Normal patient w/o Cushing Syndrome: cortisol value < 5 ug/dL and 17 OHCS of <4mg/g creatinine after the test ✔ (+) result: all results not suppressed ✔ With cushing syndrome: high level of cortisol/ value not suppressed ⮚ Midnight Salivary Cortisol Test ✔ Midnight: lowest level of cortisol ✔ Even if it’s already night, if you test the cortisol using the saliva, the result would be still high PROCEDURE FOR LOW - DOSEDEXAMETHASONE SUPPRESSION TEST ✔ 0 mg oral dexamethasone every 6 hours for 2 days ✔ 24 hour urine and serum samples are collected ✔ (+) result: elevated cortisol levels Confirmatory Test ⮚ Low-dose dexamethasone suppression test PROCEDURE FOR LOW - DOSEDEXAMETHASONE SUPPRESSION TEST ✔ 0 mg oral dexamethasone every 6 hours for 2 days ✔ 24 hour urine and serum samples are collected ✔ (+) result: elevated cortisol levels ✔ for the normal individual, cortisol should be low 🡪 not suppressed among the patient with cushing syndrome ⮚ Midnight plasma cortisol (> 7.5 ug/dL) ⮚ CRH stimulation test ⮚ Buffalo hump- fat deposits on the back of the patient ; midsection are bigger, moon face ⮚ since adrenal glands are affected, weak androgens could also be affected ✔ for the female, Hirsutism (excessive growth of dark or coarse hair in a male-like pattern), Amenorrhea (absence of menstruation) , or even infertility can be developed ✔ for the male, Gynecomastia and hyperglycemia can be developed ⮚ ACTH Dependent: the increase in the cortisol is due to the stimulation of the ACTH (high ACTH produced by the pituitary) ✔ Primary ACTH (pituitary disease🡪 the problem is the pituitary) ✔ Ectopic ACTH 🡪 there’s a malignant cell that secretes its own ACTH ✔ Ectopic CRF/CRH 🡪 high level of CRH are released from the hypothalamus ⮚ ACTH Independent: high levels of cortisol is being produced even without the stimulation of ACTH ✔ Adrenal adenoma ✔ Adrenal carcinoma ✔ Nodular adrenal hyperplasia ✔ Exogenous glucocorticoids ADRENAL INSUFFICIENCY ⮚ Low baseline cortisol levels (8:00 am,supine) and an elevated ACTH > 200 pg/mL (PRIMARY) ✔ Adrenal gland is the problem🡪 doesn’t release cortisol will feedback to the pituitary 🡪 will release ACTH ⮚ Lower serum concentrations of ACTH and cortisol (SECONDARY) ✔ Pituitary is the problem 🡪 doesn’t release ACTH 🡪 no stimulation 🡪 low cortisol ⮚ The cortisol level is decreased in BOTH PRIMARY AND SECONDARY PRIMARY HYPOCORTISOLISM/PRIMARY ADRENAL INSUFFICIENCY ⮚ Due to decreased cortisol production- 90% destruction of the adrenal cortex; aldosterone deficiency; excess ACTH release ⮚ DISORDER: ✔ Addison’s Disease – low cortisol, high ACTH ✔ Hypotension, hyponatremia, hyperkalemia,weight loss, hyperpigmentation) ✔ Due to autoimmune adrenalitis, tuberculosis,hemorrhage, HIV/AIDS infection ⮚ SCREENING TEST: ✔ ACTH Stimulation Test/Cosyntropin stimulation test
CCHM321A(LEC) 5
11ß HYDROXYLASE DEFICIENCY ⮚ 2 ND most common form of CAH ⮚ INCREASED LEVEL of 11 - deoxycortisol are indicative of this disorder ⮚ Associated with virilization and hypertension 3ß HYDROXYSTEROID DEHYDROGENASE ISOMERASE DEFICIENCY ⮚ Results to ELEVATED RATIO of 17α- hydroxypregnenolone to 17α- hydroxyprogesterone and INCREASED RATIO of DHEA to androstenedione ⮚ It is characterized by pseudohermaphroditism in female infants and incomplete musculinization in male infants ⮚ Pseudohermaphroditism: the patient has a gonads (testes/ovaries) that is present according to their chromosome; but the problem is they have external genitalia of the opposite sex ✔ ex. For females they have Clitorimegaly🡪 enlargement of labia resembling base scrotume ✔ ex. For males they have Gynecomastia🡪 development of the breast C-17,20-LYASE/ 17Α- HYDROXYLASE DEFICIENCY ⮚ Is characterized by INABILITY TO CONVERT 17a- hydroxypregnenolone to DHEA and 17a- hydroxyprogesterone to androstenedione. ⮚ It will result to DECREASE androgen, cortisol, and estrogen synthesis; DECREASE progesterone synthesis ⮚ For females, ABSENCE of menstruation (amenorrhea) and DEFECTIVE ovarian maturation ⮚ For males, pseudohermaphroditism possess both genitals of male and female; exists only in parasites ALDOSTERONE ⮚ Major electrolyte regulating hormone ⮚ Its action is to absorb/reabsorb the sodium into the kideny tubules and excrete potassium ⮚ MOST POTEN MINERALCORTICOIDS ⮚ A steroid hormone that helps regulate the water and electrolytes and blood volume ⮚ Acts on renal tubular epithelium to INCREASE RETENTION of Na and Cl, and excretion of K and H- promotes 1:1 exchange of Na for K or H (inverse relationship) ✔ High aldosterone = more sodium will be reabsorbed ✔ Hydrogen has a role in Ph🡪 high hydrogen = metabollic acidosis STIMULATORS OF ALDOSTERONE ⮚ Angiotensin II, ACTH, elevated serum potassium, renin ⮚ RAAS is stimulated when there’s a decreased blood pressure or decreased in sodium level or decreased perfusion in kidneys🡪 the juxtaglomerular apparatus of the kidney will release the renin 🡪 renin will activate the angiotensinogen that is present in the liver 🡪 will become the angiontensin I 🡪 angiontensin I will be activated by the enzyme ACE (angiotensin converting enzyme) that is present in the lungs will the convert angiontensin I to angiontensin II 🡪 will caue vasoconstriction to make the available blood to reach the vital organs (kidneys) 🡪 angiontensin II will activate aldosterone 🡪 will reabsorb sodium, will return the sodium into the blood then the water will follow 🡪 increased blood volume,bp INHIBITORS/SUPPRESSOR OF ALDOSTERONE ⮚ progesterone and dopamine ⮚ Atrial natriuretic peptide (ANP) (hormone secreted from the heart; released when bp is high; promotes urinary excretion of the sodium), intracellular calcium, and certain drugs are aldosterone suppressors, including ketoconazole, Angiotensin-converting enzyme (ACE) inhibitors,nonsteroidal anti-inflammatory drugs, and heparin ⮚ Aldosterone is produced from the zona glomerulosa of the adrenal cortext ⮚ Hypoaldosteronim: decrease in aldosterone level 🡪 no reabsorbtion of sodium 🡪 sodium will be excreted and potassium, hydrogen will be reabsorbed 🡪 renal tubular acidosis ⮚ Hyperaldosteronims: increase in aldosterone level 🡪 will cause hypertension, hypokalemia. Metabollic alkalosis ALDOSTERONE ⮚ The synthesis of this hormone is primarily controlled by the RAAS ⮚ 18 - hydroxysteroid dehydrogenase- anenzyme needed for the synthesis of aldosterone CLINICAL DISORDERS ⮚ Primary Hyperaldosteronism (Conn’sDisease) ⮚ Secondary Hyperaldosteronism ⮚ Hypoaldosteronism ⮚ Others: ✔ Liddle’s Syndrome ✔ Bartter’s Syndrome ✔ Gitelman’s Syndrome PRIMARY HYPERALDOSTERONISM (CONN’S DISEASE) ⮚ Elevation of aldosterone Caused by aldosterone secreting adrenal adenoma 🡪 cancer in adrenal gland ⮚ Associated with the elevated level of plasma aldosterone and low level or renin 🡪 no stimulation from the renin but there’s still hypersecretion of the aldosterone ⮚ Symptoms: hypertension, hypokalemia, hypernatremia and metabolic alkalosis ⮚ Screening Test: ✔ plasma aldosterone concentration /plasma renin activity ratio (PAC/PRA) ● (+) result: > 30 ratio of aldosterone with the renin: suggestive of primary hyperaldosteronism >50 ratio: diagnostic of primary hyperaldosteronism ⮚ Confirmatory Test ✔ Saline Suppresion Test ● For normal individual, upon the administration of salt 🡪 increased salt 🡪 aldosterone is not needed ● but in this condition aldosterone is still high ● (+) result: > 5 ng/dL aldosterone ● Procedure for Saline Suppression Test: Involves infusing 2 L of 0% saline over 4hours, or by administering 10-12 mg NaCltablet daily for 3 days
CCHM321A(LEC) 6
✔ Captopril suppression ● It suppress the synthesis of aldosterone ● Involves 3 hours of taking 50mg of captopril ● For normal individual the result will be decreased aldosterone ● But in this condition, aldosterone is still high; not suppressed SECONDARY HYPERALDOSTERONISM ⮚ Excessive acitvation of the RAAS 🡪 more aldosterone will be released ⮚ Occurs as a result of excessive production of renin ⮚ Secondary Hyperaldosteronism that result in hypokalemia (more sodium is reabsorbed then more potassium is secreted): ✔ Renal artery stenosis, diuretic therapy, malignant hypertension, and congenital defects in renal salt transport such as Bartter’s Syndrome and Gitelman’s Syndrome LIDDLE’S SYNDROME ⮚ Also known as pseudohyperaldosteronism ⮚ Caused by the mutation into the gene called SCNN1B gene ⮚ Congenital disorders that is characterized by increased ENaC activity (epithelium sodium channel activity) in the collecting ducts in the absence of increased aldosterone. ✔ It means that the kidney epithelium is continously reabsorbing sodium even without the stimulation coming from the aldosterone ⮚ Resemble primary aldosteronism clinically, but aldosterone level is low BARTTER’S SYNDROME ⮚ Caused by the mutation into the gene called SLC12A1 gene ⮚ “Bumetanide-sensitive chloride channel mutation” ⮚ A rare potassium-losing autosomal recessive disorder, caused by defective NaCl reabsorption in the thick ALH ⮚ Accompanied by elevated concentrations of aldosterone and renin 🡪 there’s an imbalance in the potassium,sodium and chloride GITELMAN’S SYNDROME ⮚ Caused by the mutation into the gene called SLC 12A3 gene ⮚ Thiazide sensitive transporter mutation ⮚ Associated with the defect in NaCl reabsorption that occurs in the distal convoluted tubule ⮚ Accompanied by elevated aldosterone HYPOALDOSTERONISM ⮚ Due to the destruction of the adrenal glands and deficiency of glucocorticoid ⮚ Low aldosterone 🡪 sodium excretion will be affected 🡪 potassium and hydrogen reabsorption ⮚ Associated with enzyme 21-hydroxylase deficiency ⮚ Symptoms: hyperkalemia and metabolic acidosis ⮚ Test: ✔ Furosemide Stimulation Test or Upright Posture
- Furosemide is diuretic; promotes urination by excreting sodium therefore it stimulates aldosterone secretion ● (+) result: low aldosterone level ✔ Saline suppression Test 🡪 introducing a salt water which supposedly suppress the aldosterone but in this test result is high aldosterone level 🡪 indicative of adrenal gland problem ● (+) result: high aldosterone level ⮚ Things to Consider: ✔ Blood samples for aldosterone test should be drawn in the morning before the patient has gotten out of bed- to avoid markedly increased result 🡪 because adrenal hormones are affected by suuden postural change ✔ Aldosterone levels are lower at night ✔ Methods for Aldosterone Measurement: RIA and Chromatography WEAK ANDROGENS/ADRENAL ANDROGENS ⮚ Prodcued from the zona reticularis ⮚ Serves as precursor for the production ofmore potent androgens and estrogens in tissues ⮚ Precursors: Pregnenolone and 17-hydroxypregnenolone ⮚ E. Dehydryoepiandrosterone (DHEA)and androstenedione ⮚ DHEA- principal adrenal androgens that isconverted to estrone/E1 (estrogen 1) ⮚ They circulate bound to steroid hormonebinding globulin (SHBG) ⮚ Excessive production can be confirmed bymeasuring total and free testosteroneand DHEAS ADRENAL MEDULLA ⮚ 10% of adrenal gland and inner most portion- dark mahogany color ⮚ Composed primarily of chromaffin cells that secrete catecholamines ⮚ L-tyrosine is the precursor of the cathecolamines ⮚ Norepinephrine and epinephrine are metabolized by monoamine oxidase and cathecol- 0 - methyltransferase to form metanephrines and VMA ⮚ Ratio of norepinephrine to epinephrine inserum is 80: ⮚ The hormones are 50 % protein bound ⮚ Hormones produced: ✔ Norepinephrine🡪 converted by the cathecol- 0 - methyltransferase (COMT); converted to normetanephrines
ALMA 1
REPRODUCTIVE HORMONES and OTHER MISC. HORMONES
CLINICAL CHEMISTRY 2 Rmt REPRODUCTIVE HORMONES ➢ Testosterone ➢ Dehydroepiandrosterone (DHEA) ➢ Estrogen ➢ Progesterone OTHER HORMONES ➢ Pancreas ✓ Glucagon, Insulin, Somatostatin ➢ Other Miscellaneous Hormones ✓ Human Chorionic Gonadotropin ✓ Human Placental Lactogen ✓ Gastrin ✓ Serotonin ✓ Inhibin A TESTOSTERONE ➢ PRINCIPAL AND MOST POTENT androgen hormone ➢ Synthesized by the Leydig Cells of the testis of the male, derived from the hormone progesterone ➢ Controlled by gonadotropin, which pertains to FSH and LSH that are produced from the pituitary gland ➢ Function: very important for the growth and development of the reproductive system, the prostate and also the external genitalia; exhibits circadian rhythm ➢ Levels demonstrate a circardian pattern and peak at 8am and fall to their lowest level at 8pm ➢ There is gradual reduction of testosterone after age of 30 with an average decline of 110 ng/dl every decade of life ➢ Test for male infertility: ✓ Which includes seminalysis, FSH and LH measurement ➢ Reference Values: 3 – 7 ng/mL (serum) ➢ 2 main transport proteins of testosterone: ✓ Sex hormone binding globulin (SHBG)- transports 60 % of the testosterone ✓ Albumin- 40 % ✓ Concentration determines the level of testosterone into the circulation TYPES OF TESTICULAR INFERTILITY
- Pretesticular Infertility (secondary hypogonadism) ➢ Due to lesions in the hypothalamus or pituitary ➢ Testosterone, FSH, LH – concentrations are either normal or decreased
- Testicular Infertility (primary hypogonadism) ➢ May be congenital ✓ cryptorchidism (absence of one or both testis from the scrotum) ✓ Klinefelter’s syndrome/XXY syndrome (male develops female features like weaker muscles. Greater height, poor coordination,less body hair, smaller genitals and breast development ✓ 5 - a-reductase deficiency wherein males have genitalia that appears female ✓ Acquired
- varicocele (enlargement of veins in the scrotum)
- tumor, orchitis (inflammation of the testicle) ➢ decreased testosterone levels and increased FSH and LH ➢ Problem is in the testicles
- Posttesticular infertility ➢ Due to disorders of sperm transport and function ➢ Testosterone, FSH, and LH- concentrations are all normal OTHER DISORDERS OF SEXUAL DEVELOPMENT A. TESTICULAR FEMINIZATION SYNDROME ➢ Most severe form of androgen resistance syndrome, resulting in it lacks of testosterone action in the target tissue ➢ Physical development pursues the female phenotype, with fully developed breast and female distribution of fat and hair ➢ No utility or response to administration of exogenous testosterone ➢ Lab tests: normal levels of testosterone with elevated FSH and LH B. SERTOLI CELL-ONLY SYNDROME ➢ Characterized by lack of germ or sperm cell ➢ Men present with small testes, high FSHlevels, azoospermia (Semen that lacks sperm cell), and normaltestosterone level ➢ Testicular biopsy is the only procedure to confirm this diagnosis C. KALLMANN’S SYNDROME ➢ A result of an inherited, X-linked recessivetrait that manifests as hypogonadism during puberty and the impaired sense of smell DEHYDROEPIANDROSTERONE ➢ The principal androgen formed by the adrenal cortex of the adrenal gland; not produced by the gonads ➢ Valuable in the assessment of adrenal cortical hormones ESTROGEN ➢ Arises through structural alteration of the hormone testosterone molecule; it arise from the male hormone ➢ Function: ✓ In conjunction with progesterone, the function in uterine growth and regulation of menstrual cycle and maintenance of pregnancy ➢ Deficiency: irregular and incomplete development of the endometrium (is the area for the implantation of the fertilized egg) ➢ Precursor: cholesterol, acetate,progesterone and testosterone ➢ Three Forms: Estrone (E1), Estradiol (E2), Estriol (E3) ➢ Estrone and estriol are metabolites of intraovarian and extraglandular conversion A. ESTRONE/E ➢ Most abundant estrogen in post-menopausal women B. ESTRADIOL/E 2 ➢ Most potent in the major estrogen secreted from the ovary ➢ Synthesized from testosterone, then diffuses out of the thecal cells of the ovaries of the female ➢ Precursor of both E1 and E3 – serve as negative feedback for FSH hormone → increase with the E2 will cause the inhibition of secretion of FSH ➢ Used to assess ovarian function ➢ Transport proteins: ✓ Albumin→ 60% of E2 are bound to it ✓ SHBG (Sex hormone binding globulin) → 38% of E are bound to it ✓ Free form→ 2% of E2 are bound to it
ALMA 2
D. ESTRIOL/E
➢ Metabolite of the estradiol (E2) ➢ Estrogen found in the maternal urine ➢ Its formation in pregnant women is dependent on the fetal and placental function ➢ Used to assess the fetoplacental unit , postdate gestations and intrauterine retardation ➢ Used as marker for Down Syndrome together with the chorionic gonadotropin (HCG), Inhibin A, Alpha-fetoprotein (AFP) ➢ Preferred specimen: plasma PROGESTERONE ➢ Produced by the granulose (lutein) cells of the corpus luteum in the female ➢ Dominant hormone responsible for the luteal phase cycle among females ➢ Single best hormone to determine whether the ovulation has occurred or if the female is fertile ➢ Primarily for the evaluation of fertility in female ➢ Deficiency: failure of implantation of the embryo ➢ Metabolites: pregnanediols, pregnanediones, pregnanelones TEST FOR MENSTRUAL CYCLE DYSFUNCTION AND ANOVULATION ➢ Estrogen ➢ Progesterone ➢ FSH ➢ LH TEST FOR FEMALE INFERTILITY ➢ HCG ➢ PRL ➢ FT ➢ TSH ➢ FSH ➢ LH ➢ Estradiol ➢ Progesterone PANCREAS ➢ A digestive gland in the gastrointestinal system ➢ FUNCTIONS:
- Exocrine: ➢ Responsible for the sythesis of digestive enzymes specifically the amylase and the lipase ➢ Its functional secretory unit as an exocrine gland is the Acinus/Acini: responsible for the synthesis of hormones
- Endocrine ➢ Responsible for the synthesis ➢ Alpha cells (20-30%) – secretes glucagon ➢ Beta cells (60-70%) – secretes insulin ➢ Delta cells (2-8%) - secretes somatostatin ➢ All of them are in the islets of Langerhans HUMAN CHORIONIC GONADOTROPIN/HCG ➢ Produced by the trophoblast cells of the placenta ➢ Serves to maintain the progesterone production by the corpus luteum in the early pregnancy ➢ Can be detected 2 - 3 days after ovulation ➢ Qualitative test for urine samples has detection limit of about 50 mIU/mL which is used as a basis for the Pregnancy Test (PT) kits ➢ Method: Immunometric (sandwich) method HUMAN PLACENTAL LACTOGEN/HPL ➢ Functionally, structurally and immunologically similar to the Growth Hormone and Prolactin ➢ Stimulates the development of the mammary gland specially during lactation ➢ Increases maternal plasma glucose level and promotes positive nitrogen balance ➢ Important in the diagnosis of intrauterine growth retardation GASTRIN ➢ A peptide secreted by the stomach ➢ Released in response to the vagal stimulation or vagus nerve stimulation and also presence of food in the stomach ➢ Causes secretion of the hydrochloric acid (HCL) by the parietal cell into the stomach ➢ Diagnostic marker for Zollinger-Ellison syndrome (ZES) a disease in which tumor causes the stomach to produce too much acid resulting to peptic ulcer ➢ Major stimulus: presence of amino acids ➢ Increased levels: ZES, Achlorhydria (absence of stomach acid) ,Chronic Renal Failure because gastrin is secreted into the urine also GASTRIC FLUID ACIDITY ➢ G cell→ produces the gastrin which stimulates the parietal cell ➢ Parietal cell→ produces the HCL and the intrinsic factor (needed for the B12 absorption) ➢ Chief cell → produces the pepsinogen which then converted to pepsin (by gastric acid) which is important for the breakdown of protein into smaller peptides BAO BAO/MAO NORMAL PERICIOUS ANEMIA GASTRIC CARCINOMA DUODENAL CANCER ZOLLINGER- ELLISON SYNDROMEX SEROTONIN (5 HYDROXYTRYPTAMINE) ➢ An amine derived from hydroxylation and decarboxylation of the amino acid tryptophan ➢ Synthesized by argentaffin cell primarily in GI tract ➢ Also found in high concentration in pineal gland and CNS ➢ Binds to platelets and released during coagulation ➢ It contributes to the sense of well-being and also happiness <3, and maintains mood balance ➢ It affects the mood, appetite, sleep, memory and sexual drive <<<<<< ➢ Urinary metabolites: 5 - Hydroxyindoleacetic acid (5-HIAA) ➢ Test for 5-HIAA: Ehrlich's Aldehyde SOMATOSTATIN ➢ Also called growth hormone inhibiting hormone ➢ Found in the GIT, hypothalamus and delta cells of the pancreas ➢ An inhibitor of growth hormone, glucagon, insulin INHIBIN A ➢ a reproductive system hormone which inhibits FSH activity METHODS SAMPLE FOR HORMONAL ASSAY 1. whole blood: LH and Testosterone 2. ✓ EDTA plasma :(ACTH, ADH, PTH) ✓ Heparinized plasma: (Cathecolamines, Cortisol, Dopamine, FSH) 3. Serum ✓ Aldosterone, androstenedione, DHEA, estrogen, FSH, GH, HCG, progesterone 4. Urine : Estriol ✓ Boric Acid (1 g/dL) preserves estriol and estrogen for 7 days ✓ 10 ml 6N HCL is added to 3-4 L of container (cathecolamines, vanillylmandelicacid, 5-HIAA)
OUR LADY OF FATIMA UNIVERSITY I PAMPANGA CAMPUS I COLLEGE OF MEDICAL LABORATORY SCIENCE I CLINCHEMISTRY 1
TOXICOLOGY
CLINICAL CHEMISTRY 2 LECTURE: FINALS Rmt TOXICOLOGY study of the mechanism on how a toxin causes damage or disease to the body; talks about toxic substances or poisons ⮚ study of the adverse effects of xenobiotics (substances or drugs not produced in the body) in humans. ⮚ Five Major Disciplines of Toxicology
- Mechanistic Toxicology
- Descriptive Toxicology
- Regulatory Toxicology
- Forensic Toxicology
- Clinical Toxicology MECHANISTIC TOXICOLOGY ⮚ cellular and biochemical effects of toxins ⮚ provide a basis for rational therapy design and the development of tests to assess the degree of exposure of poisoned individuals. DESCRIPTIVE TOXICOLOGY introduces toxin to an experimental animal to determine the level of toxicity that can damage the animal → predict level of toxicity that can harm to humans → risk assessment ⮚ uses the results from animal experiments to predict what level of exposure will cause harm in humans REGULATORY TOXICOLOGY ⮚ Involves the interpretation of the combined data from mechanistic and descriptive studies ⮚ is used to establish standards that define the level of exposure that will NOT POSE A RISK to public health or safety. Example: Food and Drug Administration (FDA) - tests products in the market if it contain high amount of toxins (e. mercury, lead) or chemicals that can cause risk to the public health FORENSIC TOXICOLOGY performed for medico-legal purposes to know the cause of death (specific toxin) ⮚ primarily concerned with the harmful consequences of toxin exposure. ⮚ Focuses on establishing and validating the analytic performance of the methods used to generate evidence in legal situations, including the ___________________. Example: Scene of the Crime and Operatives (SOCO) CLINICAL TOXICOLOGY performed in the laboratory (CC department) ⮚ the study of interrelationships between toxin exposure (xenobiotics) and diseases determine the cause of the signs and symptoms → identify the toxin causing it ⮚ emphasizes not only diagnostic testing but also therapeutic intervention. once the cause is identified, therapy can also be determined (antidotes binding to toxins to remove its toxic effects and will be eliminated from the body) ENVIRONMENTAL TOXICOLOGY studies pollutants to the water, soil and air ⮚ includes evaluation of environmental chemical pollutants and their impact on human health Example: Department of Environment and Natural Resources (DENR) EXPOSURE TO TOXINS ⮚ 50% - intentional ex: suicide attempt (intake of poisonous substances) ⮚ 30% of cases - accidental exposure ex: negligence (cleaning agent used for silver which is colorless and odorless) ⮚ 20% - homicide or occupational exposure (industrial worker in manufacturing paints or uses heavy metals; farmers using chemical pesticides and fertilizers) ROUTES OF EXPOSURE ⮚ Toxins can enter the body via several routes: ● ingestion ● inhalation esp. if the toxin is in a gaseous or vapor form ● transdermal meaning absorbed thru the skin ⮚ Mechanism of Absorption of toxins from the gastrointestinal tract ✔ taken up by processes intended for dietary nutrients passive diffusion - toxins, along with the food is absorbed at the same time bec. intestines cannot distinguish the harmful substances from non harmful → liver which is a metabolic organ that filters substances absorbed from the intestine before it reaches the general circulation → first pass (everything absorbed in the intestine must first pass through the kidney for detoxification) so it is the first organ to be affected by poisoning ✔ absorbed by intestine TERMINOLOGIES
- acute toxicity – single, short-term exposure ex. accidental exposure
- chronic toxicity – repeated exposure for extended periods of time ex. occupational exposure (paint or battery manufacturing company)
- toxic dose 50 (TD50) – the dose that would be predicted to produce a toxic response in 50% of the population
- lethal dose 50 (LD50) – the dose that would predict death in 50% of the population
- effectivity dose 50 (ED50) – the dose that would be predicted to be effective or have therapeutic benefit in 50% of the population DOSE-RESPONSE RELATIONSHIP
OUR LADY OF FATIMA UNIVERSITY I PAMPANGA CAMPUS I COLLEGE OF MEDICAL LABORATORY SCIENCE I CLINCHEMISTRY 2
Categorize diff. chemicals using the toxicity rating → depends on the amount that will show toxicity effects to an individual Dose is per kilogram not per individual ANALYSIS OF TOXIC AGENTS ⮚ Select the best specimen for selected test saliva, blood, urine, hair or nails (both for chronic exposure since toxins can be deposited in these areas - keratin, a protein that has an affinity for metals) so it is important to know what type of spx should be used to a specific type of toxin mercury - DO NOT use urine, due to a possibility that this metal cannot be found in the urine arsenic - could be missed if blood is used ⮚ specimen collection, handling, and storage TWO-STEP ANALYSIS OF TOXIC AGENTS ANALYSIS: 1. SCREENING TEST highly sensitive test that can detect even in low concentrations but lacks specificity and has cross reactivity so it is validated using confirmatory testing rapid, simple, qualitative test (presence or absence) for toxic substances ⮚ Immunoassays, thin layer chromatography (TLC) 2. CONFIRMATORY METHOD ⮚ GC-MS gas chromatography and mass spectrometry ⮚ ICP-MS Inductively coupled plasma mass spectrometry ⮚ AAS Atomic absorption spectrometry TOXIC AGENTS 1. ALCOHOL ⮚ commonly abused substance ⮚ CNS depressant ⮚ disorientation, confusion, and euphoria, which can progress to unconsciousness, paralysis, and, with high-level exposure,even death ⮚ some of the alcohols can even cause blindness, and acidosis ⮚ Symptoms of intoxication begin when the concentration of the alcohol to the blood is > 0% w/v ⮚ proof: pertains to the amount of alcohol that is present in a solution ⮚ 80 proof alcohol: contains 40% of alcohol (divided by 2) ⮚ full stomach will have a 3 times slower absorption of alcohol than an empty stomach a. Ethanol (Grain Alcohol) b. Methanol (Wood Alcohol) c. Isopropanol (Rubbing Alcohol) d. Ethylene glycol (1,2-ethabediol) Among these substances, ethanol is the most abused,it is used to make alcoholic beverages a. ETHANOL (GRAIN ALCOHOL) COMMON INDICATORS OF ETHANOL ABUSE TEST COMMENTS GGT gamma- glutamyl transferase (GGT) → an indicator for chronic alcoholism or for occult alcoholism
- increases can be seen before the onset of pathologic consequences → sensitive marker for alcoholism but the problem is increases in serum activity can occur in many non-ethanol- related conditions → meaning it is non specific marker AST → a liver enzyme
- increases in serum activity can occur in many non-ethanol- related-conditions → non specific marker AST/ALT ratio De Ritis Ratio→ ratio of the AST/ALT
- a ratio of greater than 2 is highly specific for ethanol- related liver disease → alcoholic hepatitis HDL - high serum HDL is specific for ethanol consumption MCV - increased erythrocyte MCV is commonly seen with excessive ethanol consumption
- increases are not related to folate or vitamin B12 deficiency ➢ also called as ethyl alcohol, beer alcohol ➢ called grain alcohol since it is prepared thru fermentation of grains like wheat, rice (rice wine) ⮚ Ethanol abuse causes acidosis due to the production of acetic acid – accumulation of ketones and lactate ⮚ Causes diuresis → frequent urination/polyuria (ethanol suppress the action of the ADH) ⮚ Hangover symptoms are due to the effect of the by product of ethanol metabolism called “acetaldehyde” ⮚ 80 mg/dl of alcohol is the statutory limit for the operation of motor vehicle ⮚ 50 g/day of ethanol can lead to the accumulation of lipids into the hepatocytes can lead to fatty liver → alcoholic hepatitis → can progress to liver cancer HOW DOES THE ETHANOL CONVERTED INTO OUR BODY? BIOTRANSFORMATION: ETHANOL → converted to ACETALDEHYDE thru the action of the enzyme alcohol dehydrogenase → converted
OUR LADY OF FATIMA UNIVERSITY I PAMPANGA CAMPUS I COLLEGE OF MEDICAL LABORATORY SCIENCE I CLINCHEMISTRY 4
⮚ Inhibits cellular respiration, electron transport and ATP formation ⮚ At low levels of exposure, patients experience headaches, dizziness, and respiratory depression, which can rapidly progress to seizure, coma, and death at slightly greater doses ⮚ has a bitter almond odor ⮚ Antidote: sodium thiosulfate ⮚ Toxic levels: more than 2 ug/ml ⮚ Laboratory Analysis: ✔ Ionspecific electrode methods and photometric analysis following two-well microdiffusion separation ✔ urinary thiocyanate concentration. ARSENIC ⮚ odor of garlic and has a metal base ⮚ Component of ant poisons,rodenticides, paints and metal alloys ⮚ common homicide and suicide agent ⮚ heavy metal poisoning ⮚ It expresses its toxicity by high affinity binding to thiol groups in protein ⮚ high affinity binding to keratin → can be used in chronic exposure ⮚ salvarsan→ used to treat syphilis; made up of arenic ⮚ fish arsenic→ found among predatory fish (salmon, mackerel) ⮚ Evaluating long-term exposure ✔ Specimen: hair and nail especially for chronic exposure - one of the clue for arsenic exposure is the presence of the mees lines in nails (might also indicate ascorbic acid def.) ✔ Ion Emission Spectroscopy ⮚ Evaluating short-term exposure ✔ Specimen: ● Blood (arsenic will only last in the blood for few hours) ● urine (specimen of choice since arsenic can persist up to 6 days) ✔ AAS ⮚ Acute Fatal Dosage: 120 mg ⮚ Other Method for Testing: ✔ Reinsch test → not only specific for arsenic CADMIUM ⮚ use in electroplating and galvanizing ⮚ also present in tobacco ⮚ pigment found in paints and plastics and is the cathodal material of nickelcadmium batteries ⮚ expresses its toxicity primarily by binding to proteins ⮚ Toxicity may also result to destruction of type 1 epithelial cells in the lungs (collapse of the lungs) and decreased resistance to bacterial infection ⮚ also targets the kidney→ renal tubular defect (RTD), glucosuria, aminoaciduria ⮚ has a half-life of 10 - 30 years in our body ⮚ Laboratory Analysis: ✔ Whole blood or urine- AAS LEAD ⮚ common environmental contaminant ⮚ A potent enzyme inhibitor ⮚ most distinctive feature: can decrease the IQ points especially in the children ⮚ Low level exposure may cause behavioral changes- hyperactivity and attention deficit disorder/ADHD/PDD and also affects IQ because the toxic effect of the lead may cause ??? of the peripheral nerves → causes decreased in nerve conduction ⮚ lead is also used in paints and also in children toys ⮚ Vitamin D and heme synthesis are affected – lead blocks D-ALA synthetase, producing anemia → lead poisoning can cause microcytic hypochromic anemia ⮚ to the peripheral blood (PBS), basophilic stippling can be seen ⮚ It has characteristic “wrist drop or foot drop” manifestation → lead affects nerve conduction ⮚ Treatment: EDTA and Dimercaptosuccinic acid ⮚ Toxicity Dose: > 0 mg/day ⮚ Fatal Dose: 0 g ⮚ Toxic Blood Levels: >70 ug/dl (definitive) ⮚ Samples: whole blood (used for quantitative testing exact value of the lead), urine (used for recent/acute lead exposure) and hair (used for chronic exposure) ⮚ half-life of > 20 years in the hard tissue ⮚ half-life of 120 days in the soft tissue EFFECTS OF LEAD ⮚ Acute Exposure- Abdominal or neurological symptoms manifest. ⮚ Neurologic symptoms- encephalopathy characterized by a cerebral edema and ischemia. ⮚ Severe lead poisoning can result in stupor, convulsions, and coma. ⮚ CDC cut-off for normal level of lead in children: less than 10 ug/dl ⮚ FDA is very important in checking different products for their lead conten INDICATORS OF LEAD ⮚ Urinary D-ALA ⮚ Free RBC porphyrin ⮚ Presence of Basophilic Stippling in RBC TESTS ⮚ Graphite Furnace AAS ⮚ Inductively Coupled Plasma Emission Spectrophotometry (ICPS) ⮚ Anodic Stripping Voltammetry ⮚ Zinc protoporphyrin or free RBC protoporphyrin test MERCURY ⮚ can be seen in sphygmomanometer, thermometer ⮚ single drop of mercury can poison the whole room ⮚ Binds with protein and also an enzyme inhibitor ⮚ Exists in three forms: ✔ Elemental (liquid) ✔ Inorganic salts ✔ Component of organic compounds
OUR LADY OF FATIMA UNIVERSITY I PAMPANGA CAMPUS I COLLEGE OF MEDICAL LABORATORY SCIENCE I CLINCHEMISTRY 5
⮚ Inorganic mercury- tachycardia, tremors, Thyroiditis, and, most significant, a disruption of renal function ⮚ Organic mercury- neurologic symptoms ✔ Low levels of exposure cause tremors, behavioral changes, mumbling speech, and loss of balance. Higher levels of exposure result in hyporeflexia, hypotension, bradycardia, renal dysfunction, and death ⮚ Sample for Testing: ✔ Whole blood (organic mercury) – AAS ✔ Urine (inorganic mercury) - anodal stripping voltammetry ⮚ Method for Testing: ✔ Reinsch Test ⮚ Significant Exposure: > 50 ug/dl (whole blood) PESTICIDES ⮚ Organophosphates and carbamates function by inhibition of acetylcholinesterase (neurotransmitters which are important in signaling between nerve endings) ⮚ Low levels of exposure are associated with salivation, lacrimation, and involuntary urination and defecation ⮚ Higher levels of exposure result in bradycardia, muscular twitching, cramps, apathy, slurred speech, and behavioral changes. ⮚ Death due to respiratory failure may also occur. ⮚ Pesticide exposure usually happen to farmers called occupational exposure) METHODS ⮚ Evaluation of erythrocytic acetylcholinesterase activity ⮚ measurement of serum pseudocholinesterase ⮚ cholinesterase and pseudocholinesterase are markers pesticide and insecticide poisoning where their concentrations decreases
Cchmlecfinals - Lecture notes
Course: Clinical Chemistry 2 (MDT 3122L)
University: Our Lady of Fatima University
- Discover more from:
