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Biomedical subjects

M M Godbole

Publications and source records attributed to M M Godbole.

At least 19 recordsLinked to original sources

Simultaneous exposure of excess fluoride and calcium deficiency alters VDR, CaR, and calbindin D 9 k mRNA levels in rat duodenal mucosa.

Fluoride ingestion reduces intestinal calcium absorption; its molecular basis has not been studied. We studied the mRNA expression of calcium-sensing receptor (CaR), vitamin D receptor (VDR) and calbindin D 9 k (D 9 k) by northern blot analysis in the duodenal mucosa of rats. Weanling pups fed with chow diet containing adequate calcium (0.5% w/w) and drinking water (NaF < 1 ppm) served as controls (Group I) and were studied at 9 and 15 weeks. The pups, born to rats fed with a calcium-deficient diet (0.03%) and excess fluoride water (NaF 50 ppm), were continued on the same diet and water (Group II) until 9 weeks of age. Subsequently, Group II rats were divided into 4 subgroups; 3 subgroups with fluoride free water [II-A adequate calcium, II-B excess calcium (Ca 2%) and II-D calcium deficient], whereas II-C received fluorinated water and adequate calcium diet until 15 weeks. At 9 weeks, as compared to group-I, group-II had decreased VDR (P < 0.001) and D 9 k mRNA (P < 0.001), whereas CaR mRNA levels increased (P < 0.05). At 15 weeks, as compared to group-I, VDR mRNA further reduced in group II-D (P < 0.001) and II-C (P < 0.001), whereas it increased in group II-A. Removal of fluoride ingestion and calcium replenishment increased D 9 k mRNA expression, maximally in adequate calcium group (P < 0.001), while it was further reduced in group II-C (P < 0.001). CaR expression decreased significantly in all the groups. We conclude that excess fluoride reduces the mRNA levels of VDR and D 9 k in the duodenal mucosa of rats, thereby possibly reducing calcium absorption. Calcium supplementation with simultaneous fluoride removal improves their expression.

Animals↗

Hypothyroidism alters the expression of Bcl-2 family genes to induce enhanced apoptosis in the developing cerebellum.

Thyroid hormone (TH) deficiency results in delayed proliferation and migration of cerebellar granule cells. Although extensive cell loss during the development of the cerebellum under hypothyroid conditions is known, its nature and its mechanism are poorly understood. Bcl-2 family gene expression is known to determine the fate of cells to undergo apoptosis. We evaluated the effect of hypothyroidism on Bcl-2 family gene expression in the developing rat cerebellum. Electrophoresis and Western blotting were used to analyze DNA fragmentation and expression of DNA fragmentation factor (DFF-45), Bcl-2, Bcl-xL and Bax genes respectively. In the hypothyroid condition, extensive DNA fragmentation and enhanced cleavage of DFF-45 were seen throughout development (postnatal day 0 to day 24) and adulthood whereas they were absent in the euthyroid state. The anti-apoptotic genes Bcl-2 and Bcl-xL were down-regulated and the pro-apoptotic gene Bax was expressed at higher levels compared with the euthyroid state. These results suggest that normal levels of TH prevent cerebellar apoptosis to a large extent, whereas hypothyroidism not only increases the extent but also the duration of apoptosis by down-regulating the anti-apoptotic genes and maintaining a high level of the pro-apoptotic gene Bax.

Animals↗

Hypothyroidism alters mitochondrial morphology and induces release of apoptogenic proteins during rat cerebellar development.

Thyroid hormone (TH) deficiency leads to extensive apoptosis during cerebellar development, but the mechanism still remains unclear. Different signals also converge on mitochondria during apoptosis to induce the release of apoptogenic proteins that activate proteolytic cascade through specific enzymes called caspases. Here we studied the effect of hypothyroidism on alterations in mitochondrial structure and translocation of apoptogenic molecules during rat cerebellar development. Structural analysis of mitochondria was studied by electron microscopy. The translocation of apoptogenic molecules was analyzed by Western blotting. TH deficiency led to vacuolization, enlargement and decrease in the number of cristae. The majority of the proapoptotic molecule, Bax, was localized in mitochondria under hypothyroid conditions whereas a limited presence of Bax was detected in the euthyroid state. Translocation of cytochrome c, apoptosis-inducing factor (AIF) and second mitochondrial-derived activator of caspases (SMAC) from mitochondria to cytosol was detected primarily in early developmental stages in the hypothyroid condition. These experimental results demonstrate that TH maintains mitochondrial architecture and inhibits the release of apoptogenic molecules to prevent excess apoptosis during cerebellar development.

Animals↗

Effect of oophorectomy on expression of calcium sensing receptor mRNA in rat duodenal mucosa.

Calcium sensing receptor (CaR) in duodenal mucosa may be involved in active calcium absorption. Estrogen deficiency results in decreased intestinal calcium absorption. Effects of bilateral oophorectomy (OVX) have been studied on calcium homeostasis, bone mineral density (BMD) and CaR mRNA levels in duodenal mucosa at 4 weeks in adult female Sprague Dawley rats and compared with those in sham-operated and control group. There was no significant change in serum corrected calcium, inorganic phosphorous, calcidiol and intact parathyroid hormone in all the three groups. OVX rats had a significant decline in serum estrogen (E2) levels and alkaline phosphatase. They also had a significant decrease in BMD (DXA) at lumbar spine in vivo, and proximal and distal tibia in vitro while there was no significant change in serum E2 and BMD parameters in sham-operated and control rats. Northern blot analysis revealed no significant change in the CaR mRNA expression in duodenal mucosa in all three groups. The results suggests that CaR mRNA expression in duodenal mucosa is not affected by physiological circulating concentrations of estradiol in rats.

Animals↗

Short-term androgen deprivation does not alter CaR and VDR mRNA expression in duodenal mucosa in male rats.

Androgen deprivation is associated with decline in intestinal calcium absorption. The effect of androgen on CaR and VDR intestinal mucosa has not yet been studied. Calcium homeostasis, a real bone mineral density (aBMD, dual energy X-ray absorptiometry) and expression of CaR and VDR mRNA in duodenal mucosa of orchidectomized (ORX) and sham operated (Sham) adult Sprague Dawley rats at 4 week have been studied. There was no significant difference in serum calcium, alkaline phosphatase, calcidiol and calcitriol levels between both the groups. Serum testosterone (T) (ng/dl) and inorganic phosphorous (iP) (mg/dl) levels were significantly lower in ORX rats. As compared to sham rats, ORX rats had significant decline in in-vitro aBMD at proximal, middle and distal tibia, proximal, mid and distal femur and femoral neck (P < 0.05). Northern blot analysis revealed no significant alteration in the CaR and VDR mRNA expression in duodenal mucosa in ORX rats. CaR and VDR mRNA expression in duodenal mucosa is therefore, not affected by physiological concentrations of testosterone in rats.

Androgens↗

Expression of peroxisome proliferator-activated receptors (PPARS) in human astrocytic cells: PPARgamma agonists as inducers of apoptosis.

We report the isolation by RT-PCR of partial cDNAs encoding the human peroxisome proliferator-activated receptor (PPAR) isoforms PPARbeta and -gamma in human primary astrocytes (HPA) as well as in the human malignant astrocytoma cell line T98G. In contrast, we failed to detect PPARalpha mRNA in either of these two cell types. Because PPARbeta is ubiquitously expressed but has, as yet, no known function, we pursued our functional studies of these cells with regard to PPARgamma. To that end, we showed that PPARgamma protein is abundantly expressed in both cell types, having a molecular weight of approximately 50 kDa. Immunocytochemistry revealed a predominantly nuclear localization of this receptor. Moreover, incubation of the two cell types with 1-12 mcM 15-deoxy PGJ(2) or 1-12 mcM ciglitazone, both of which are agonists of PPARgamma, induced loss of cellular viability as assessed by the MTT assay after a 4 hr incubation. Reduced cellular viability as a consequence of exposure to PGJ(2) or ciglitazone resulted from induction of apoptosis, as assessed by DNA fragmentation and Hoechst staining, and involves activation of the CPP32 (caspase-3) protease. These data show that modulation of the process of apoptosis is one function of PPARgamma in cells derived from the human astrocytic lineage.

Apoptosis↗

Learning disabilities and poor motivation to achieve due to prolonged iodine deficiency.

The effect of prolonged iodine deficiency on learning and motivation was studied. One hundred male children--matched for age, socioeconomic status, and formal education--were selected from both severely iodine-deficient (SID) and mildly iodine-deficient (MID) villages. Mean urinary iodine excretion was significantly lower in the SID than in the MID group (219.84 +/- 57.52 compared with 449.14 +/- 32.31 nmol/L, P < 0.001). The serum thyroxine concentration was significantly lower (90.36 +/- 6.46 compared with 123.70 +/- 15.42 nmol/L, P< 0.001) and serum thyroid-stimulating hormone (TSH) was significantly higher in the SID group than in the MID group (6.23 +/- 0.34 compared with 4.85 +/- 0.28 mU/L, P< 0.01). The children were administered maze, verbal, and pictorial learning tasks and a test of motivation. The results showed that SID children are slow learners compared with MID children. In both groups the rate of learning over trials was superior in younger (aged 9-12 y) children although the initial performance of older (aged 12-15 y) children was better (P < 0.01). SID children scored significantly lower than MID children on the achievement motivation scale (P < 0.01). The results are suggestive of neural impairment as well as poor sociopsychologic stimulation, resulting in learning disability and lowered achievement motivation. Unless iodine nutrition is improved in the community as a whole, these abnormalities may prevent millions of children from the SID areas from achieving their full potential even if learning opportunities are made available to them.

Achievement↗

Differential expression of alpha- and beta-thyroid hormone receptor genes in the developing rat brain under hypothyroidism.

One of the most alarming observations of iodine deficiency disorders (IDD) is neurological cretinism which is caused due to lack of T3 during the crucial stages of brain development. We have developed an iodine-deficient rat model to study the pattern of T3 receptor genes expression in the brain during postnatal development under iodine deficiency. We observed increased expression of c-erbA-alpha 2 and -beta 1 T3 receptor transcripts while c-erbA-alpha 1 remains unchanged in the brain of the iodine-deficient neonates compared with their euthyroid counterparts. Up-regulation of the beta 1 form in the developing brain under iodine deficiency is suggestive of an adaptive process coming into play to protect it from the damages that are inflicted due to hypothyroidism. Though the significance of the increased alpha 2 form in the iodine-deficient rat brain has not yet been ascertained, it can be conjectured that it acts as a homeostatic control over 'functional receptor' (namely beta 1) under developmental hypothyroidism.

Animals↗

Organochlorine pesticide exposure and thyroid function: a study in human subjects.

We examined the serum levels of thyroxine and thyroid stimulating hormone in 103 rural subjects with respect to blood levels of organochlorine pesticide and occupation. We found that 24.3% of study subjects had depleted thyroxine levels in association with significantly lower organochlorine pesticide residues in blood. Sex, nutritional status, thyromegaly, or handling of pesticides in the course of work were not found to be factors contributing to depleted thyroxine levels.

Adult↗

Reversible impairment of glucose tolerance in patients with endemic fluorosis. Fluoride Collaborative Study Group.

Endemic fluorosis is a condition resulting from prolonged ingestion of drinking water which contains excess fluoride. Studies on rats have suggested that fluoride toxicity may produce glucose intolerance and abnormalities in insulin secretion. We studied glucose and insulin profiles following an oral glucose load in patients with endemic fluorosis. Twenty-five young adults (age range, 15-30 years) with endemic fluorosis, and an equal number of matched healthy control subjects with normal fluoride intake were studied. Impaired glucose tolerance was demonstrated in 10 of 25 (40%) patients with endemic fluorosis. Patients with impaired glucose tolerance had significantly higher fasting serum immunoreactive insulin (p < 0.05), higher fasting serum fluoride (p < 0.001), and a significantly lower fasting glucose to insulin ratio than that in patients with normal glucose tolerance (p < 0.001) or control subjects (p < 0.05). The fasting serum fluoride levels correlated positively with the area under the glucose curve (r = 0.80, p < 0.01) in patients with impaired glucose tolerance. Interestingly these abnormalities could be reversed when the village was provided drinking water with fluoride levels within acceptable limits. The present study shows that chronic fluoride toxicity in humans could result in significant abnormalities in glucose tolerance which are reversible upon removal of the excess fluoride.

Adolescent↗

5'-Monodeiodinase activity in developing human cerebral cortex.

Iodine status of aborted fetuses (11-25 wk gestation) was determined on the basis of maternal thyroid status and urinary iodine excretion. Fetal cerebral cortex thyroxin and 3,5,3'-triiodothyronine (T3) contents peaked at 15-18 wk gestation and then fell in iodine sufficiency. In mild iodine deficiency T3 concentration was maintained at a higher level until week 22, although it were still significantly less than in the iodine-sufficient group. Reverse T3 (rT3) rose from 11 to 22 wk gestation without any effect of iodine status. The activity of 5' and 5-monodeiodinase also increased from 11 to 22 wk gestation, with 5' monodeiodinase activity significantly increased by mild and moderate iodine deficiency. In contrast, cerebral cortex 5-monodeiodinase activity was significantly lower in moderate iodine deficiency at 15-18 wk gestation. The observations indicate that cerebral cortex 5' and 5 monodeiodinase activities are modulated in iodine deficiency to enhance T3 production from thyroxin (T4) during the period that coincides with neuroblastogenesis.

Cerebral Cortex↗

Late-onset adrenal hyperplasia in north Indian hirsute women.

The occurrence of late-onset congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency was studied in 60 consecutive hirsute women by means of adrenocorticotrophin (ACTH)-stimulated serum 17-hydroxyprogesterone (17-OHP) levels. Five (8.3%) women had an exaggerated response (ACTH-stimulated 17-OHP 3,160 +/- 560 ng/dl). All of them had regular periods and 3 were virilized. The other 2 were indistinguishable from those with idiopathic hirsutism or polycystic ovarian disease.

17-alpha-Hydroxyprogesterone↗

Iodine deficiency and neonatal hypothyroidism.

The incidence of neonatal hypothyroidism, as reflected in cord-blood thyroxine and thyrotropin levels, varied from 0.6% to 13.3% in iodine-deficient and normal regions of India (selected districts of Uttar Pradesh and Kerala and the city of Delhi), depending on the degree of environmental iodine deficiency. In populations with a high incidence of neonatal hypothyroidism, an increased prevalence of nerve deafness and a shift to the left in the distribution of IQ scores (towards lower scores) have been demonstrated. These indications of mild brain damage suggest that nutritional iodine deficiency can present in other ways than goitre or cretinism. Determination of the incidence of neonatal hypothyroidism using dried cord-blood spot screening appears to be the most useful and reliable method to assess the risk of brain damage in iodine-deficient areas.

Congenital Hypothyroidism↗

Plasma lipoprotein(a) levels in patients with pulmonary arterial hypertension.

BACKGROUND: Pulmonary artery hypertension is a common sequelae of a variety of cardiac and lung diseases. Pathogenesis of primary and secondary pulmonary artery hypertension is still debatable. METHODS AND RESULTS: We studied the serum lipoprotein(a) levels in patients with primary (n=27) and secondary (n=19) pulmonary artery hypertension (Eisenmenger syndrome). The results were compared with age and sex matched controls (n=46). We also studied the frequency of high levels of lipoprotein(a) (> 30 mg/dl) in pulmonary artery hypertension. Mean lipoprotein(a) levels were significantly higher in the pulmonary artery hypertension group compared to age- and sex-matched controls (31.60+/-15.49 mg/dl v. 14.66+/-14.7; p=0.0001). All patients were classified into two groups on the basis of their lipoprotein(a) levels (<30 mg/dl and >30 mg/dl). There was a higher frequency of lipoprotein(a) >30 mg/dl in patients of pulmonary artery hypertension v. controls (52% v. 24%; p= <0.001). Younger age, higher functional class, more severe congestive heart failure, shorter duration of symptoms. and more cases of hemoptysis were observed in the group with lipoprotein(a) >30 mg/dl. CONCLUSIONS: High lipoprotein(a) may be a marker and be associated with a more adverse prognosis in severe pulmonary artery hypertension. Larger prospective studies are needed to establish lipoprotein(a) as a risk factor for the development of pulmonary artery hypertension.

Adult↗

Single daily dose of carbimazole in the treatment of hyperthyroidism.

BACKGROUND: The antithyroid drugs, methimazole and carbimazole, are conventionally used in divided daily doses. However, these drugs have a longer intrathyroidal than a plasma half-life. We undertook this prospective, controlled study, in an area of mild iodine deficiency, to compare the efficacy of a single daily dose of carbimazole with divided doses in the treatment of hyperthyroidism. METHODS: Nineteen patients with hyperthyroidism received 30 mg of carbimazole daily at bed time (group A) while 14 received 10 mg of carbimazole every 8 hours (group B). These patients were assessed clinically and biochemically by estimation of serum total thyroxine, total triiodothyronine and thyrotropin before and 1, 2, 3, 4 and 6 weeks after treatment. RESULTS: There was no significant difference between mean baseline concentrations of thyroxine and triiodothyronine. After 1, 2, 3, 4 and 6 weeks there was a decline in their concentrations which was similar in both groups (p > 0.05). Euthyroidism was achieved in 4.6 +/- 1.4 weeks (range 2-6 weeks) in group A and in 3.8 +/- 1.2 weeks (range 3-6 weeks) in group B (p > 0.05). CONCLUSIONS: We conclude that carbimazole in a single daily dose is an effective method for treating hyperthyroidism in an area of mild iodine deficiency and its efficacy is comparable to divided dose therapy. This practical and acceptable method of treatment can be specially useful in patients who find it difficult to remember to take divided doses.

Adolescent↗

Iopanoic acid as an adjunct to carbimazole in the management of hyperthyroidism.

BACKGROUND: The thiourea drugs take a few weeks to control the symptoms of hyperthyroidism whilst iodine containing radiographic contrast agents (iopanoic acid and sodium ipodate) have a more rapid effect. There is no report on the use of iopanoic acid administered in conjunction with carbimazole, so we evaluated the efficacy of this combination in the early medical management of patients with hyperthyroidism. METHODS: Thirty hyperthyroid patients diagnosed by clinical and biochemical criteria were randomized into two treatment groups. Group A (n = 16) received iopanoic acid (500 mg orally twice a day for the first 3 weeks) and carbimazole (30 mg orally in three divided doses) while group B (n = 14) received carbimazole alone. Clinical examination and estimation of serum total T3, total T4 and TSH were done by radioimmunoassay at the start of therapy, weekly for 4 weeks and then at 6, 8 and 12 weeks. RESULTS: In the initial 3 weeks, iopanoic acid induced a significantly greater fall in mean serum total T3 levels (Z = 2.298, p < 0.02) and a slower fall in mean serum total T4 (Z = 2.396, p < 0.05) in group A patients compared to those in group B. This was accompanied by earlier clinical improvement in group A patients. The mean serum total T3 and T4 values rose to higher levels in group A at 4 weeks, one week after discontinuation of iopanoic acid. At the end of 12 weeks, however, there was no significant difference in the mean serum total T3 and T4 levels between the two groups (p > 0.05). Biochemical euthyroidism (i.e. total T3 < 3 nmol/L and total T4 < 170 nmol/L) was achieved later in group A patients than in group B (10.4 +/- 5.0 weeks v. 3.6 +/- 1.2 weeks, p < 0.0001). CONCLUSIONS: Iopanoic acid given together with carbimazole induces rapid clinical improvement in hyperthyroid patients than carbimazole alone. However, the delayed achievement of euthyroidism may preclude its routine use in the management of patients with hyperthyroidism except in those with thyrotoxic emergencies.

Adult↗