Presence of 25(OH) D deficiency in a rural North Indian village despite abundant sunshine.

BACKGROUND AND OBJECTIVE: Several studies have shown wide prevalence of vitamin D deficiency with serum 25(OH)D <49.9 nmol/L in urban Indians related to their poor sunshine exposure and skin pigmentation. However, there is limited information in rural Indians. We hypothesized presence of higher 25(OH)D in rural subjects as compared to urban because of farming related abundant sunshine exposure. DESIGN AND METHODS: We assessed serum 25(OH)D levels in residents of a North Indian village with 200 families, located 90 km East of Delhi during February (winter). Fifty seven subjects (32 males and 25 females) from 50 families consented for the study. RESULTS: The mean 25(OH)D values of all subjects in the rural area was 36.4 +/- 22.5 nmol/l/L. Males had significantly higher 25(OH)D values than females. When compared to urban subjects, the mean 25(OH)D value of rural males and females was six and three folds higher, respectively. However even with five hours of daily sunshine exposure only 31.5% had serum 25(OH)D levels > or = 50 nmol/L. CONCLUSIONS: Thus, with longer sunshine exposure subjects residing in rural area had better mean 25(OH)D values than that of urbans. However, 70% of them were still vitamin D deficient. These facts indicate the need for the countrywide vitamin D food fortification program irrespective of rural or urban setting.

The physiology of vitamin D : current concepts.

The vitamin D endocrine system, besides playing pivotal roles in calcium homeostasis & bone mineral metabolism, is now recognized to subserve a wide range of fundamental biological functions in cell differentiation, inhibition of cell growth as well as immuno modulation. Vitamin D is a prohormone which is converted into its active hormonal form 1, 25 (OH)D2 D, 1, 25 (OH)D2 D activates its cellular receptor (VDR) which activate target genes to engender its biological actions. This review provides a summary of recent understanding of the complex actions of the vitamin D hormone 1, 25 (OH)2 D which is a final product of 1alpha hydroxylation in the proximal tubular cells of kidneys. Emerging evidence also indicates both 1, 25 (OH)2 D3 independent as well as depended action of vitamin D receptor (VDR). Thus, the vitamin D system action may involve more than one single receptor and legand. The presence of 1alpha hydroxylase in many target cells other than proximal renal tubular cells indicates autocrine and paracrine functions for 1, 25 (OH)2 D3 in the control of cell proliferation and differentiation. Vitamin D and related molecules belong to a elaborate endocrine system that acts on target genomic receptors in several organ systems to control cell proliferation and differentiation.

Prevalence & potential significance of vitamin D deficiency in Asian Indians.

Studies from our center and other parts of India have drawn attention towards wide prevalence of vitamin D deficiency (VDD) in our country. VDD has been reported in all age groups including toddlers, school children, pregnant women and their neonates and adult males and females residing in rural and urban India. We reviewed implications of VDD in our population based on the preliminary data available from Indian studies on skeletal health. Besides, a brief review is made on the importance of VDD in various other disorders prevalent in equivalent proportions among Indians such as type 2 diabetes mellitus (DM), cardiovascular diseases (CVD), immune competence including relation to tuberculosis, malignancy and osteoarthritis. Data from the West have also associated VDD with increased prevalence of type 2DM, CVD, autoimmune disorders, tuberculosis, prostate, breast and colon malignancy and osteoarthritis. Such association has not been studied to date in our country. Overall results of various studies conducted to date in urban and rural Indians indicate that widely prevalent VDD is functionally relevant to skeletal health including osteomalacia and rickets. However, there is a need to explore its association with osteoporosis related fractures and various other non skeletal disorders linked with VDD.

Reversal of subclinical adrenal insufficiency through antituberculosis treatment in TB patients: a longitudinal follow up.

BACKGROUND & OBJECTIVE: Subclinical adrenal insufficiency has been shown to occur in patients with tuberculosis. Whether this insufficiency can be reversed with therapy and on long-term follow up, is not known. We studied the effect of antituberculosis treatment (ATT) with respect to reversal of the adrenal insufficiency, as assessed by response to standard dose adrenocorticotropin (ACTH) stimulation test in TB patients. METHODS: One hundred and five HIV-negative tuberculosis patients were studied. Of these, 72 patients had pulmonary and 33 had extrapulmonary forms of the disease. Baseline (pre-treatment) standard-dose ACTH stimulation test was done on all the subjects, following which, they were put on standard antituberculosis therapy, depending on the type of disease and were followed up for a period of 30 months. ACTH stimulation tests were performed at follow up, every 6 months. RESULTS: Baseline (pre-treatment) standard-dose ACTH stimulation test revealed an impaired response in 52 of 105 patients (49.5%). At 6 months, the percentage of responders had increased to 71 per cent with a gradual increasing trend noted thereafter. At 24 months, 31 of the 32 patients (97%) who were followed up demonstrated a normal response to ACTH stimulation. The percentage of responders was comparable in both pulmonary [21 of 22 patients (95%)] and extrapulmonary TB [10 of 10 patients (100%)] groups at follow up. INTERPRETATION & CONCLUSION: Our study shows that nearly half of patients with active tuberculosis had a subclinical adrenal insufficiency indicated by an impaired response to ACTH stimulation test. This insufficiency reverse with therapy in most patients on long-term follow up.

Bone mineral parameters in healthy young Indian adults with optimal vitamin D availability.

BACKGROUND: Several recent studies indicate a marked prevalence of vitamin D deficiency in asymptomatic, apparently healthy urban subjects from different socioeconomic groups in north India. METHODS: To further examine this trend, we studied 40 men and 50 women, 20-30 years of age, from the Indian paramilitary forces. These individuals consume a nutritious, high-protein diet, have optimal exposure to sunlight and undertake strenuous outdoor physical exercise. RESULTS: The mean serum calcium, phosphorus and alkaline phosphatase levels were normal in both men and women. The mean (SD) serum intact parathyroid hormone and 25-hydroxyvitamin D3 levels were 19.3 (8.2) pg/ml and 18.4 (5.3) ng/ml in men, and 11.9 (6.6) pg/ml and 25.3 (7.4) ng/ml in women. Bone mineral density estimated in 20 men and 22 women revealed that in comparison with white Caucasians, 35%-50% of men and 14%-32% of women were osteopenic at different sites, while an additional 10% of men had osteoporosis of the lumbar spine. CONCLUSION: We found that with optimal nutrition, good sunlight exposure and regular physical exercise, healthy young individuals have normal bone and mineral biochemical values. The reasons for the abnormalities detected in bone mineral density in them needs further study. The impact of childhood nutrition on accumulation of peak bone mass may contribute to our findings. There is a need for establishing normative bone mineral density data for Indians.

Adrenocortical reserve and morphology in tuberculosis.

Ninety seven patients (63 males, mean age 31.8 years, SD 2.3) with various forms of tuberculosis were studied. All of them were HIV negative. Thirty normal control subjects (16 males, mean age 36.4 years, SD 1.8) were also studied. Fifty-eight of the 97 patients (59.8%) were malnourished (BMI < 18 kg/m2). The mean basal serum cortisol was lower in the TB group (n = 91) (351 nmol/1; SD 150) as compared to the normal control group (n = 8) (402 nmol/1; SD 93) but this difference did not attain statistical significance. Following administration of synthetic ACTH (cosyntropin), the 30 and 60 minutes mean serum cortisol values in the TB group were significantly lower as compared to the normal control group (p < 0.05). Forty five of the 91 patients (49.5%) who underwent the ACTH stimulation test had compromised adrenal reserve. Fourteen of the 86 patients (16.3%) in whom adrenal morphology was studied revealed adrenal gland enlargement on abdominal CT scan. ACTH stimulation was done in 12 of these 14 patients and eight of them had compromised adrenal reserve. Repeat ACTH stimulation done six months to one year after treatment in 13 patients revealed significantly increased 30 minutes (p < 0.05) and 60 minutes (p < 0.05) serum cortisol values. While nine of these 13 patients were negative responders before treatment, only three of them had evidence of compromised adrenal reserve after one year of antituberculosis treatment, (p < 0.05). Serum cortisol values in patients with drug-sensitive and drug-resistant tuberculosis did not differ significantly. Patients with drug-resistant tuberculosis had a higher prevalence of adrenal gland enlargement (7 of the 30) as compared to those with drug-sensitive tuberculosis (7 of the 56) (p = NS). Subclinical adrenal insufficiency is prevalent in a significant number of patients with both drug-sensitive and drug-resistant tuberculosis, and in some of these it is associated with adrenal gland enlargement. The compromised adrenal reserve and enlargement seem to reverse with therapy.

Dyspnoea, lung function & respiratory muscle pressures in patients with Graves' disease.

To understand the pathophysiology of dyspnoea in patients with hyperthyroidism, lung function, maximum inspiratory, expiratory respiratory muscle pressures (MIP and MEP) and intensity of dyspnoea (after six minutes walking test) were recorded in 12 consecutive patients with active Graves' disease. Reassessment was done after achieving euthyroidism with 8-12 wk of carbimazole therapy. Patients covered similar distance during 6 min walking before and after carbimazole therapy. However, there was a significant reduction in dyspnoea following euthyroidism. This was accompanied by significant decrease in respiratory rate, minute ventilation, forced expiratory volume in one second (FEV1%) and improvement in the forced vital capacity (FVC). No significant changes in tidal volume (TV) and maximum-midexpiratory flow rates (MMEFR), MIP and MEP were observed. Lung function parameters, MIP and MEP did not correlate with the severity of dyspnoea. Serum T4 levels correlated inversely with the distance covered during 6 min walking test, MIP and MEP. To conclude, increased breathing effort in presence of reduced FVC may lead to dyspnoea during hyperthyroid phase in patients with active Graves' disease. Lack of correlation between the severity of dyspnoea and abnormalities in lung function suggests that other mechanisms of dyspnoea may also operate in these patients.

Autonomic dysfunction and peripheral vasodilatory response in diabetes.

Twenty three diabetes mellitus patients were investigated for peripheral vasodilatory response in relation to degree of autonomic dysfunction. The non-insulin dependent diabetes mellitus (NIDDM) patients had significant degree of autonomic dysfunction. Based on standard scoring system for evaluating autonomic dysfunction, diabetics were divided into 'borderline' (n = 12) and 'severe' (n = 11) diabetic autonomic neuropathy (DAN) groups. The severe DAN patients showed significantly lower pressor response when compared to borderline DAN patients. Severe DAN was also associated with significant peripheral vascular dysfunction. The severe DAN patients largely had no clinical manifestation of peripheral vascular dysfunction. Thus, at subclinical level patients with significant autonomic dysfunction do exhibit peripheral vascular dysfunction.

Remission with carbimazole therapy & assessment of T4 suppression test as an index of relapse in patients with Graves' disease in India.

This study determined the relapse rate following the use of antithyroid drugs (ATD) in patients with Graves' disease and assessed T4 suppression test as a follow up index for predicting relapse after carbimazole treatment in 21 patients who had taken 9-12 months of ATD treatment continuously with good compliance. T4 suppression test was done before stopping ATD treatment. During one year of follow up after stopping ATD therapy, 12 (57%) patients relapsed and 9 (43%) remained in remission. Six of the 12 relapses occurred in the first 3 months of stopping ATD therapy. The response following the use of carbimazole therapy was comparable to that reported from iodine sufficient western countries and may be because of the salt iodination programme in our country. T4 suppression test was normal in 14 (66%) and abnormal in 7 (34%) patients. All the patients with abnormal T4 suppression test relapsed after stopping ATD. The overall accuracy of the T4 suppression test (76%) also favourably compared with reported values of other useful but less readily available markers such as thyrotropin releasing hormone (TRH) stimulation test and thyroid receptor antibodies. Thus, in our experience antithyroid drugs were able to induce long term remission in 43 per cent patients with Graves' disease and abnormal T4 suppression test can be used as a reliable parameter for predicting relapse.

Prevalence & significance of pancreatic islet cell & adrenal antibodies in patients with Graves' disease.

The prevalence of adrenocortical (ACAb), islet cell (ICAb) and thyroid microsomal (TMAb) autoantibodies was determined by indirect immunofluorescence, in 88 consecutive patients with Graves' disease. ACAb, ICAb and TMAb positivity was seen in 3 (3.3%), 10 (11%) and 66 (75%) patients respectively. Among these one patient had both ACAb and ICAb positivity. Diabetes mellitus was found to be present in two (2.3%; both ICAb positive) of the 88 patients studied. Two of the four ICAb positive patients had loss of first phase insulin response to intravenous glucose. A significant proportion of patients of Graves' disease had associated islet cell and/or adrenal autoimmunity. A high index of suspicion for associated endocrine autoimmunity should be maintained while dealing with subjects of Graves' disease.

Primary hyperparathyroidism--an Indian study.

Twenty eight patients of sporadic primary hyperparathyroidism seen over a period of 10 years were studied. There were 18 females and 10 males with a mean age of 35.9 years. Bone involvement was the commonest clinical presentation (90%) followed by renal involvement (65%) and more than half the patients (54%) had involvement of both the skeletal and renal systems. The tumor was clinically palapable in six patients. Thalliumtechnetium subtraction scan had a sensitivity of 87% followed by computerised tomography (70%), and ultrasound (65%) in diagnosing parathyroid pathology. All the patients underwent surgical excision of the abnormal gland (S). Adenomas constituted the single largest group (90%). Histologically, only 32% of the patients had chief cell morphology. Clear cell (32%) mixed cell, and oxyphil cell (7.2%) types accounted for the remaining adenomas. Majority of the patients (82%) had symptomatic postoperative hypocalcemia requiring intravenous calcium with or without vitamin D supplementation. In contrast to western reports most of our patients were young, presented late with florid bone and renal disease and had large palpable tumors.

Islet cell antigens and autoantigen(s): Monoclonal antibodies and further characterization.

A novel series of murine monoclonal antibodies to islet cells (I-45, I-51, I-52 and I-39) have been generated using human insulinoma homogenate as the immunogen in order to characterize pathogenetically relevant islet cell autoantigen(s). Differentiation antigens recognized by these islet cell monoclonal antibodies displayed varied cytological distribution (pan-islet or peripheral mantle only). Monoclonal antibody I-45 reacted with all endocrine subsets of the pancreatic islet, similar to the reactivity of islet cell autoantibody positive sera from type I diabetes subjects. Preexposure to pH2 abolished the immunoreactivity of the autoantigen; I-45 antigen was also sensitive to low pH. Preexposure to 100° C for 1 h did not significantly alter the immunoreactivity of islet antigens recognized by ICAb positive patient sera and monoclonal antibody 1-39, thus demonstrating the extraordinary heat stability of the corresponding epitopes; those recognized by I-45 were less heat stable. Islet cells were found to share I-45 differentiation antigen(s)/epitope(s) with other neuroendocrine cells, viz. amerior pituitary, adrenal medulla and gut endocrine cells.

Ultrastructural study of mixed growth hormone & prolactin secreting pituitary adenomas.

An ultrastructural study was done on 15 mixed growth hormone (GH) and prolactin (PRL)-secreting pituitary adenomas surgically removed from acromegalic patients with hyper-prolactinaemia, in order to see whether the 2 hormones were present in the same cell or in different cells. Double labelling immunogold technique was used for simultaneous ultrastructural localization of GH and PRL. It was found that each neoplastic cell in these 15 tumours (30 to 50 cells were studied in each case) contained 4 populations of granules viz., (i) granules positive for only GH; (ii) granules positive for only PRL; (iii) granules positive for both GH and PRL; and (iv) granules negative for both GH and PRL (unlabelled). Though the relative percentage of these 4 types of granules varied from cell to cell even within the same tumour, the major population (49.9 to 96%) was constituted by the mixed granules showing labelling for both GH and PRL. Almost all the cells examined from each tumour appeared to be mammosomatotrophs. Thus, the study indicated that mammosomatotroph adenomas are perhaps more common among mixed GH and PRL--secreting pituitary adenomas than previously believed. It could be important to recognize these tumours from the therapeutic point of view.

A clinico-pathologic study of pituitary adenomas.

One hundred patients of pituitary adenoma were studied using light microscopy, electron microscopy, immunohistochemistry and serum hormone estimation. Depending on the absence or presence of clinical endocrine manifestation they were divided into 2 groups 'non-functioning' (group I -48 patients) and 'hyper-functioning' (group II- 52 patients). Tumours in group I were chromophobes, some of which (group IA) had no hormone increase in serum nor detection in tissues and ultrastructurally they consisted of secretorily inactive cells (null cell adenomas) while others (group IB) were composed of secretorily active cells with prolactin consistently increased in serum and localized in tissue (lactotroph adenomas). Tumours in group II were chromophobe, acidophil, basophil or mixed adenomas with varying number of secretorily active cells in all. The hormone responsible for the hyperfunction was always raised in serum and localized in tissue. Thus growth hormone was demonstrated in all tumours from patients with acromegaly (somatotroph adenomas), prolactin in all tumours from patients with galactorrhea (lactotroph adenomas) and ACTH in all tumours from patients with Cushing's syndrome (corticotroph adenomas). It was observed, however, that 40 per cent of tumours were pleurihormonal, growth hormone and prolactin being the commonest combination. Interestingly, not all the hormones localized by immunohistochemistry in pleurihormonal adenomas were detected in serum and/or reflected in the clinical picture.

Pancreatic islet transplantation: utility of ductular obstruction and exocrine atrophy model?

Introduction of 'silent' exocrine atrophy (and endocrine 'enrichment') in pancreatic grafts following ductular blockade may have a role in human diabetes by circumventing currently elusive islet isolation/purification protocols. To explore this potential, pancreatic isografts were performed in 12 pairs of inbred Wistar NIN rats. Donor pancreatectomy was performed after distal clamping and canulation of common bile duct and injection of 0.5 ml. polyacrylamide gel (blocked n = 7) or normal saline (un-blocked n = 5) respectively. One to 2 m.m. fragments of the resulting mildly distended pancreases were transplanted in to 2 sites (renal capsule and iliac fossa subcutaneously) of cach recipient. Post-operative biopsies of the transplanted grafts (unilateral nephrectomy and iliac fossa biopsies) revealed macroscopic and microscopic evidence of necrotizing pancreatitis in both the groups at both the sites (histiocytic and giant cell infiltration, fat necrosis and focal calcification with destruction of exocrine and endocrine cells) as early as 1 and 3 weeks. Possible detrimental factors include: volume and pressure of ductal injection, graft sites (confined spaces), post-operative wound infection and bio-compatibility of the material used for ductular blockade.