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Biomedical subjects

N Tandon

Publications and source records attributed to N Tandon.

At least 37 records · Page 2Linked to original sources

Beneficial influence of an indigenous low-iron diet on serum indicators of iron status in patients with chronic liver disease.

The main Fe storage organ in the body is the liver. In patients with chronic liver disease, secondary Fe overload is common. Phlebotomy, often used in the West to reduce Fe overload to improve the efficacy of interferon therapy, is not socially acceptable in India. We assessed the efficacy of a low-Fe diet in reducing serum Fe levels. Nineteen patients with hepatitis B- and C-related chronic liver disease, ten with normal (< 25 mumol/l) baseline serum Fe levels (group A) and nine with high (> 25 mumol/l) serum Fe levels (group B) were included. All the subjects were advised to eat a low-Fe diet. The daily Fe intake was reduced approximately 50% by consumption of the rice-based diet. Haemoglobin, serum Fe, transferrin saturation index (TSI), ferritin and alanine transaminase (EC 2.6.1.2) levels were studied at 1 and 4 months. Dietary Fe intake and body weight were closely monitored. All patients complied with the dietary regimen and at 4 months significant (P < 0.001) reductions from baseline were seen in serum Fe (20 (SD 3) v. 12 (SD 4) mumol/l group A; 30 (SD 3) v. 19 (SD 7) mumol/l group B) and TSI (38 (SD 8) v. 23 (SD 9)% group A; 53 (SD 15) v. 34 (SD 13)%, group B) in both the groups, albeit earlier in group B subjects. Serum ferritin levels, however, reduced only in group A (112 (SD 62) v. 43 (SD 25) ng/ml, P < 0.05) and not in group B. Non-significant reductions in haemoglobin levels were seen in both groups. Alanine transaminase levels reduced significantly (P < 0.05) in both the groups (95 (SD 49) v. 44 (SD 25) IU/l, group A; 82 (SD 16) v. 51 (SD 14) IU/l group B). Thus, a low-Fe diet results in significant reductions in serum Fe and TSI levels, irrespective of baseline Fe levels. This diet should be evaluated to improve the efficacy of interferon therapy in patients with hepatitis B- and C-related chronic liver disease.

Adult↗

Prevalence and significance of low 25-hydroxyvitamin D concentrations in healthy subjects in Delhi.

BACKGROUND: Despite abundant sunlight, rickets and osteomalacia are prevalent in South Asian countries. The cause of this paradox is not clear. OBJECTIVE: The objective was to assess 25-hydroxyvitamin D [25(OH)D] status and its functional significance in apparently healthy subjects residing in Delhi, a city in the northern part of India. DESIGN: Serum 25(OH)D, total calcium, inorganic phosphate, alkaline phosphatase, intact parathyroid hormone, and 1, 25-dihydroxyvitamin D [1,25(OH)(2)D] were measured in groups of healthy subjects who differed with respect to variables relevant to vitamin D and bone mineral metabolic status, such as direct sunlight exposure, season of measurement, skin pigmentation, dietary calcium and phytate contents, and altered physiologic states such as pregnancy and neonatal age. RESULTS: All groups except one with maximum direct sunlight exposure had subnormal concentrations of 25(OH)D. The 25(OH)D-deficient groups tended to have an imbalance in bone mineral metabolic homeostasis when exposed to winter weather and low dietary calcium and high dietary phytate, with significantly low calcium and elevated intact parathyroid hormone concentrations, chemical osteomalacia, or both. Increased values of 1,25(OH)(2)D during pregnancy did not help correct the imbalance in bone mineral metabolic homeostasis. CONCLUSION: Healthy subjects with low 25(OH)D concentrations are at risk of bone mineral metabolic imbalance when exposed to factors that strain bone mineral homeostasis.

Adult↗

Tissue gene expression analysis using arrayed normalized cDNA libraries.

We have used oligonucleotide-fingerprinting data on 60,000 cDNA clones from two different mouse embryonic stages to establish a normalized cDNA clone set. The normalized set of 5,376 clones represents different clusters and therefore, in almost all cases, different genes. The inserts of the cDNA clones were amplified by PCR and spotted on glass slides. The resulting arrays were hybridized with mRNA probes prepared from six different adult mouse tissues. Expression profiles were analyzed by hierarchical clustering techniques. We have chosen radioactive detection because it combines robustness with sensitivity and allows the comparison of multiple normalized experiments. Sensitive detection combined with highly effective clustering algorithms allowed the identification of tissue-specific expression profiles and the detection of genes specifically expressed in the tissues investigated. The obtained results are publicly available (http://www.rzpd.de) and can be used by other researchers as a digital expression reference.

Algorithms↗

Hashimoto's thyroiditis: countrywide screening of goitrous healthy young girls in postiodization phase in India.

Countrywide salt iodization, to prevent nutritional iodine deficiency, has been achieved in India recently. The current study was planned to evaluate the prevalence of goiter and thyroid autoimmunity and assess thyroid functional status in a cohort of 6283 healthy schoolgirls from different parts of the country in the postiodization phase. Goitrous girls (n = 1810; 28% of subjects) were investigated for serum T4 and TSH, antithyroid microsomal antibody (TMA) and antithyroglobulin antibody (TGA), urinary iodine excretion, and cytomorphology by fine-needle aspiration cytology (FNAC). FNAC carried out successfully in 764 goitrous girls revealed juvenile autoimmune thyroiditis (JAT) in 58 (7.5%), which included Hashimoto's thyroiditis in 43 (5.6%) and focal lymphocytic thyroiditis in 15 (1.9%). TMA and TGA estimated in 722 goitrous girls detected significantly positive titers of TMA (> or =1:1600) and TGA (> or =1:160) in 52 (7.2%) and 4 (0.55%) girls, respectively. Only 29 (67.4%) girls with Hashimoto's thyroiditis were TMA positive. In patients with FNAC-proven JAT, overt clinical and biochemical hypothyroidism was seen in three (6.5%) and subclinical hypothyroidism in seven (15%). Subclinical hyperthyroidism was detected in 5.1% cases of JAT, and none had overt hyperthyroidism. No definite correlation was seen between urinary iodine excretion and thyroid autoimmunity.

Adolescent↗

Role of the catheter in the treatment of cardiac arrhythmias.

During the last decade, there has been a remarkable shift away from drug therapy toward catheter-based treatment of many tachyarrhythmias. Catheter ablation using radiofrequency energy has been shown to provide a cure for many supraventricular and ventricular tachycardias with excellent safety and has now become the first line of treatment. A review of biophysics and biology of radiofrequency energy, the technique of catheter ablation, and its application in the treatment of specific tachycardias encountered in clinical practice is presented.

Arrhythmias, Cardiac↗

Breeding habitats and larval indices of Aedes aegypti and Ae. albopictus in the residential areas of Calcutta City.

Aedes aegypti and Ae. albopictus larvae were found breeding in almost all indoor and outdoor, temporary and/or permanent collections of water, either alone or in association with each other in residential areas of the city, the former throughout the year (June'97-May'98) and the latter during monsoons and post-monsoons only. Ae. aegypti showed preference for breeding in chowbachhas, indoors and Ae. albopictus for collections of water in flower pots and discarded containers and outdoors. The larval indices of both the species were highest during monsoons and post-monsoons.

Aedes↗

Residual pituitary enlargement in primary hypothyroidism despite 1 1/2 years of L-thyroxine therapy.

Pituitary hyperplasia consequent to untreated primary hypothyroidism undergoes impressive regression following thyroxine therapy. We describe a young man with primary hypothyroidism and pituitary hyperplasia, who showed significant but incomplete regression of pituitary enlargement despite 18 months of L-thyroxine therapy (1 year in replacement dose (150 micrograms/day) and an additional 6 months in suppressive dose (300 micrograms/day)).

Adult↗

Comparison of the effects of cilostazol and milrinone on intracellular cAMP levels and cellular function in platelets and cardiac cells.

Cilostazol is a potent cyclic nucleotide phosphodiesterase (PDE) type 3 (PDE3) inhibitor that was recently approved by the Food and Drug Administration (FDA) for the treatment of intermittent claudication. Its efficacy is presumed to be due to its vasodilatory and platelet activation inhibitory activities. Compared with those treated with placebo, patients treated with cilostazol showed a minimal increase in cardiac adverse events. Because of its PDE3 inhibitory activity, however, the possibility that cilostazol exerts positive cardiac inotropic effects is a safety concern. Therefore we compared the effects of cilostazol with those of milrinone, a selective PDE3 inhibitor, on intracellular cyclic adenosine monophosphate (cAMP) levels in platelets, cardiac ventricular myocytes, and coronary smooth muscle cells. We also compared the corresponding functional changes in these cells. Cilostazol and milrinone both caused a concentration-dependent increase in the cAMP level in rabbit and human platelets with similar potency. Furthermore, cilostazol and milrinone were equally effective in inhibiting human platelet aggregation with a median inhibitory concentration (IC50) of 0.9 and 2 microM, respectively. In rabbit ventricular myocytes, however, cilostazol elevated cAMP levels to a significantly lesser extent (p < 0.05 vs. milrinone). By using isolated rabbit hearts with a Langendorff preparation, we showed that milrinone is a very potent cardiotonic agent; it concentration-dependently increased left ventricular developed pressure (LVDP) and contractility. Cilostazol was less effective in increasing LVDP and contractility (p < 0.05 vs. milrinone), which is consistent with the cardiac cAMP levels. The cardiac effect of OPC-13015, a metabolite of cilostazol with about sevenfold higher PDE3 inhibition, was similar to cilostazol. Whereas milrinone concentration-dependently increased cAMP in rabbit coronary smooth muscle cells, cilostazol did not have such an effect. However, both compounds increased coronary flow equally in rabbit hearts. Our results show that although cilostazol and milrinone both inhibit PDE3, cilostazol preferentially acts on vascular elements (platelets and flow). This unique profile of cilostazol is consistent with its beneficial and safe clinical outcomes in patients with intermittent claudication.

Animals↗

Ventricular tachycardia and sudden cardiac death.

As we approach the new millennium, treatment of survivors of cardiac arrest and prevention of sudden cardiac death (SCD) are the two most important problems confronting contemporary cardiology practice. Sudden cardiac death occurs as a result of ventricular tachycardia (VT) degenerating into ventricular fibrillation (VF). Several major arrhythmia treatment trials completed during the last decade have significantly changed the way we treat patients with ventricular arrhythmias. In patients with sustained VT and aborted SCD, only treatment with implantable cardioverter defibrillator (ICD) has been shown to significantly increase survival. Amiodarone and sotalol, though very useful in the treatment of VT and VF, do not improve survival as significantly as ICD therapy. Use of Class I antiarrhythmics may adversely affect survival. Primary prevention of SCD in patients with a recent myocardial infarction (MI) and in patients with cardiomyopathy and congestive heart failure (CHF) is limited by our inability to accurately identify patients at risk of SCD. Among the many tests available to identify patients at risk of SCD, decreased left ventricular ejection fraction (LVEF) and presence of non-sustained VT appear to be most useful. To date, only beta adrenoceptor blockers have been shown to improve survival in post-MI patients as well as in patients with cardiomyopathy and CHF. Use of amiodarone is controversial in these patients. Treatment with ICD of post-MI patients with decreased LVEF and inducible sustained VT at electrophysiology study improves survival.

Anti-Arrhythmia Agents↗

Breeding habitats & seasonal variation in the larval density of Aedes aegypti (L) & Ae. albopictus (Skuse) in an urban garden in Calcutta city.

A longitudinal study on the breeding habitats and variation in the relative larval density of Ae. aegypti and Ae. albopictus was conducted in an urban garden in Calcutta city. The observations of the study, during October 1995 to September 1996 revealed that both the species showed preference for breeding in earthen, and cement pots, plant pots, chowbachhas and molluscan shells. Ae. albopictus larvae were also found in accumulations of water in bamboo stumps and tree holes. The container positivity and relative larval density of both species was highest during monsoon (June 1996-September 1996) and lowest during summer (February 1996-May 1996). The seasonal variation in container index (CI) of each species was statistically significant (P < 0.05) and showed a positive correlation with rainfall, the seasonal variation in the larval density of both Ae. aegypti and Ae. albopictus in permanent breeding sites was however not statistically significant, indicating that the CI and relative larval density of the two species was unaffected by temperature and humidity. The variation between the larval density and their CI in the same season was not significant, suggesting a perfect adaptation of Ae. aegypti, an urban, and Ae. albopictus, a sylvatic species, to more or less similar aquatic biotypes in an urban garden.

Aedes↗

Mixed germ cell tumour of the pineal region: a case report.

An intracranial mixed germ cell tumour with germinoma and teratoma components is reported. The patient presented with parinaud's syndrome and precocious puberty. The treatment involved partial surgical debulking followed by whole brain radiotherapy (4500 cGY in 25 fraction over 5 weeks) and chemotherapy (consisting of cisplatin and etoposide). Post treatment MRI showed no residual lesion. The controversies in the management are discussed.

Adolescent↗

Reversal of abnormalities of myelination by thyroxine therapy in congenital hypothyroidism: localized in vivo proton magnetic resonance spectroscopy (MRS) study.

Deficiency of thyroid hormone during central nervous system ontogeny results in a variety of clinical, anatomical and biochemical defects. Delay in thyroxine therapy in newborns with congenital hypothyroidism leads to irreversible brain damage. We have used localized in vivo proton magnetic resonance spectroscopy (MRS) to assess biochemical changes in different regions of brain in three patients with congenital hypothyroidism before and after thyroxine therapy. An abnormal lipid peak which disappeared with thyroxine therapy was observed in cerebellum and frontal lobe in one patient. Statistically significant reduction of NAA/(Cr+PCr) [P<0.009] and elevation of Cho/(Cr+PCr) [P<0.008] ratios in comparison to controls were documented in all three patients which tended to normalise with thyroxine therapy. A variety of biochemical abnormalities relatable to myelin maturation were documented and these were found to be reversible on thyroxine therapy. Reversibility was documented even though thyroxine therapy was initiated at ages beyond which abnormalities in myelinogenesis are considered irreversible. Also, proton MRS revealed biochemical heterogeneity between patients with congenital hypothyroidism.

Adolescent↗

Intra-pancreatic splenic artery pseudoaneurysm. A rare complication of chronic calcific pancreatitis.

The authors present the case of a 12-year-old boy with a history of chronic upper abdominal pain. Based on ultrasonography, endoscopic retrograde cholangio-pancreatography, and computerized tomography, a diagnosis of chronic calcific pancreatitis with dilation of the main pancreatic duct and a pseudocyst of the proximal pancreas was made. At surgery, in addition to confirmation of the above findings, a pseudoaneurysm arising from the splenic artery was found in the head and body of the pancreas. Pancreaticoduodenal resection including the pseudoaneurysm was performed. Postoperatively the child developed diabetes, which is easily managed with small doses of insulin.

Aneurysm, False↗

Insulin autoantibodies before and after carbimazole therapy in Asian Indian patients with Graves' disease.

Carbimazole therapy can induce insulin autoantibodies (IAA) in Japanese Graves' disease patients, a phenomenon possibly linked to their immunogenetic profile. This phenomenon is not observed in Caucasians. We assessed IAA levels in 114 North Indian Graves' disease patients before and after carbimazole therapy (mean duration 6.2 +/- 3.9 months). The functional significance of IAA was assessed in 46 of them by first phase (sum of +1 and +3 min) insulin response to intravenous glucose (IVGTT) and an oral glucose tolerance test (OGTT) undertaken before commencement of the carbimazole therapy. IAA were measured using a radiobinding assay and expressed as the assay precision unit, S.D. scores (S.D.S), over healthy controls. Before treatment 22 of 114 (19.3%) patients were IAA positive (mean +/- S.D., 5.9 +/- 3.2 S.D.S). After carbimazole therapy a further 11 (9.6%) showed positive for IAA (mean +/- S.D., 3.5 +/- 1 S.D.S). Of the 22 patients who were IAA positive before treatment, 12 became negative after carbimazole therapy. The fasting insulin and first phase insulin responses were similar in IAA positive and IAA negative Graves' disease patients (mean +/- S.D., 61.7 +/- 35.9 versus 88.3 +/- 46.6 pmol/l, P = 0.123 and 1127 +/- 696 versus 1033 +/- 430 pmol/l, P = 0.716, respectively). The OGTT results were comparable in the IAA positive and the IAA negative groups. Thus, North Indian Graves' disease patients, who resemble Caucasians in their HLA haplotypes, behave like Japanese in their tendency to become IAA positive with carbimazole therapy. A subset of the patients who were IAA positive before treatment also demonstrated negative IAA (12/22) after carbimazole therapy.

Adult↗

Seasonal prevalence of Anopheles stephensi larvae and existence of two forms of the species in an urban garden in Calcutta City.

A study on the occurrence and seasonal prevalence of Anopheles stephensi (principal vector of malaria in Calcutta) larvae in an urban garden in central Calcutta revealed their presence in collections of fresh and/or rain water in various kinds of temporary and permanent breeding habitats. Breeding sites in shady areas were preferred in comparison to those receiving direct sunlight. The density of An. stephensi larvae was highest in earthen and lowest in wooden pots throughout the study period, as supported by ANOVA and Wilcoxon's signed rank test. During monsoons the larval density was uniformly high in all four, i.e. earthen, stone, cement and wooden kinds of pots. The variation in the density of An. stephensi larvae due to the effect of season and nature of pots was highly significant. Co-existence of An. stephensi larvae with Aedes aegypti, Ae. albopictus and Cx. quinquefasciatus was also observed at times in certain water collections. An. stephensi population in the urban garden in central Calcutta was found to comprise of two forms the type and variety mysorensis.

Animals↗