Metabolic pathways of tetraidothyronine and triidothyronine production by thyroid gland: a review of articles.

Tetraidothyronine (T4) and Triiodothyronine (T3) are the two vital hormones in human metabolism produced by thyroid gland. The major pathways in thyroid hormone biosynthesis begin with iodine metabolism which occurs in three sequential steps: active iodide transport into thyroid followed by iodide oxidation and subsequent iodination of tyrosyl residues of thyroglobulin (Tg) to produce idotyrosines monoidotyrosine (MIT) and diiodothyrosine (DIT) on Tg. Oxidized iodine and tyrosyle residues which are an aromatic amino acids are integral part of T4 and T3. The thyroid iodine deficiency of either dietary, thyroid malfunction, or disorder of hypothalamus and pituitary to produce enough Thyroid Stimulating Hormone (TSH), eventually lead to hypothyroidism with sever side effects. Iodine oxidation is the initial step for thyroid hormone synthesis within thyroid, is mediated by thyroperoxidase enzyme (TPO), which itself is activated by TSH required for production of MIT and DIT. T4 and T3 are subsequently are synthesized on Tg following MIT and DIT coupling reaction. Thyroid hormones eventually produced and released into circulation through Tg pinocytosis from follicular space and subsequent lysozomal function, a process again stimulated by TSH. The production of T4 and T3 are highly regulated externally by a negative feed-back interrelation between serum T4, T3 and TSH and internally by the elevated iodine within thyroid gland. It is believed the extra iodine concentration within thyroid gland control thyroid hormones synthesis by inhibition of the TPO and hydrogen peroxide (H2O2) formation which is also an essential factor of iodine oxidation, via a complex mechanism. In healthy subjects the entire procedures of T4 and T3 synthesis re-start again following a drop in serum T4 and T3 concentration. On conditions of thyroid disorders, which caused by the distruption of either of above mechanisms, thyroid hormone deficiency and related clinical manifestations eventually begin to show themselves.

The children reference range of thyroid hormones in Northern Iran.

Hypothyroidism is associated with mental and growth abnormality in children. The aim of this study was to determine the reference range of thyroid stimulating hormone (TSH). Thyroxin (T4) and triodothyronine (T3) of children in Northern Iran. The sample population for this study consists of subjects of 4 age groups up to 21 years. The subjects were selected randomly from people referred to Danesh Medical Diagnostic Laboratory in Gorgan Northern Iran. Thyroid hormone level were investigated with Radio immunoassay. The mean concentration for T4, T3, TSH for the sample population of 4 groups were as follow (113.5, 107.4, 102.9, 99.2 nmol L(-1)), (1.9, 1.7, 1.9, 1.6 nmol L(-1)) and (2.1,3.5, 2.9, 2.7 mIu L(-1)). The mean value of T3, TSH were higher for females but the mean value of T4 was slightly higher in males. The findings of this investigation indicated that there is an inverse age correlation in particular for T4 in all age groups. On the bases of the results from this study, we conclude that reference range, in all age groups and lower, upper limits of our reference range are not universally similar; therefore determination of reference range in each region is a critical need for clinical practice.

A review on post-puberty hypothyroidism: a glance at myxedema.

Hypothyroidism, is a thyroid disorder accompanied by serum thyroid hormone reduction when thyroxin T4, the main thyroid hormone, reduced, it is followed by disruption of a negative-feed back auto regulatory mechanism on pituitary gland and subsequent thyroid stimulating hormone (TSH) which is released into the blood circulation to stimulate the thyroid gland to produce enough thyroid hormone to compensate for the body hormone requirements. Therefore, reduced serum thyroxin(T4) in principle, triidothyronine (T3) and elevated TSH are laboratory indices for the diagnosis of hypothyroidism. At early stage of hypothyroidism although laboratory measurements of thyroid function test are manifest the thyroid disorder but the patient clinical signs and symptoms may remain unnoticed. If the patient undiagnosed and untreated the condition of hypothyroidism worsen and the clinical manifestation begin to show itself and myxedema is a definition given to the whole picture of untreated hypothyroidism at very end stage the patients enter into myxedema comma with eventual death due to the sever symptoms of hypothyroidism. Among important causative factors leading to catastrophic events in myxedema is life threatening hypothermia, heart and cerebral dysfunctions.

Maternal serum zinc deficiency in cases of neural tube defect in Gorgan, north Islamic Republic of Iran.

Previous studies have shown a high rate of neural tube defects (NTD) in Gorgan, northern (tub efcs (NTD) in Gorgan, northern Islamic Republic of Iran. This case-control study during 2003-04 compared serum zinc levels and other variables in 23 mothers of neonates affected with NTD and 36 mothers with normal healthy neonates in Dezyani hospital in Gorgan. Mean serum zinc levels in the case and control groups were 13.43 micromol/L (SD 6.3) and 11.41 micromol/L (SD 6.3) respectively. Zinc deficiency was found in 13 (36.5%) of the cases and 7 (19.4%) of the controls. Logistic regression analysis showed an association between the presence of NTD and zinc deficiency (OR 5.06; 95% CI: 1.51-16.94).

Maternal serum zinc deficiency in cases of neural tube defect in Gorgan, north Islamic Republic of Iran

Previous studies have shown a high rate of neural tube defects [NTD] in Gorgan, northern Islamic Republic of Iran. This case-control study during 2003-04 compared serum zinc levels and other variables in 23 mothers of neonates affected with NTD and 36 mothers with normal healthy neonates in Dezyani hospital in Gorgan. Mean serum zinc levels in the case and control groups were 13.43 micromol/L [SD 6.3] and 11.41 micromol/L [SD 6.3] respectively. Zinc deficiency was found in 13 [36.5%] of the cases and 7 [19.4%] of the controls. Logistic regression analysis showed an association between the presence of NTD and zinc deficiency [OR 5.06; 95% CI: 1.51-16.94]

Efficacy of DOTS strategy in treatment of respiratory tuberculosis in Gorgan, Islamic Republic of Iran.

We carried out a follow-up cohort study of 260 smear-positive patients [178 on directly observed treatment, short-course (DOTS); 82 on non-DOTS] over a 2-year period to evaluate the efficacy of the DOTS strategy in treatment of tuberculosis (TB). All the patients had had cough for > 3 weeks; 91.9% had fever, 60.8% of them with sputum; and 27.7% had a positive family history. The rate of treatment failure with DOTS was 9.0% at the end of the 2nd month and 1.7% at the beginning of the 5th month. In the control group these rates were 18.3% and 7.3% respectively. The DOTS strategy significantly increased the success rate of TB treatment (P < 0.05).

Age related prostate-specific antigen reference range among men in south-East Caspian Sea.

The purpose of this study was to describe the distribution of serum prostate specific antigen (PSA) and to determine age-specific reference range in a population of Persian men. Venous blood samples were taken from 287 men, from Gorgan located in the North of Iran, South-East of Caspian Sea, aged 15 > or = 80 year. The serum PSA levels was measured using Enzyme-linked Immunosorbant-Assay (ELISA) technique and age-specific range for PSA level was determined. The serum prostate-specific antigen level for six age group of 15-40 years, 41-50 years, 51-60 years, 61-70 years, 71-80 years and >80 years were mainly in the range of 0-2.5 ng mL(-1), for 76.6%, 2.6-4 ng mL(-1) for 9.1% and as whole 85.7% of all men in this study had < or = 4 ng mL(-1), 8.7 and 5.6% all men of six age group had PSA level of 4.1-10 ng mL(-1) and >10 ng mL(-1), respectively. The findings of present study indicated that a large proportion (76.6%) men in this region have a lower PSA level of 0-2.5 ng mL(-1) and only 9.1% of men have PSA level of 2.6-4 ng mL(-1). It is therefore concluded that acceptable reference range of 0-4 ng mL(-1) for PSA level require further reassessment.

Efficacy of DOTS strategy in treatment of respiratory tuberculosis in Gorgan, Islamic Republic of Iran

We carried out a follow-up cohort study of 260 smear-positive patients [178 on directly observed treatment, short-course [DOTS]; 82 on non-DOTS] over a 2-year period to evaluate the efficacy of the DOTS strategy in treatment of tuberculosis [TB]. All the patients had cough for > 3 weeks; 91.9% had fever, 60.8% of them with sputum; and 27.7% had a positive family history. The rate of treatment failure with DOTS was 9.0% at the end of the 2nd month and 1.7% at the beginning of the 5th month. In the control group these rates were 18.3% and 7.3% respectively. The DOTS strategy significantly increased the success rate of TB treatment [P < 0.05]