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Biomedical subjects

N Tandon

Publications and source records attributed to N Tandon.

At least 19 recordsLinked to original sources

Treatment with extracts of Momordica charantia and Eugenia jambolana prevents hyperglycemia and hyperinsulinemia in fructose fed rats.

Insulin resistance has been implicated as a major contributor to the development of hyperglycemia in NIIDM patients. Herbal extracts of Momordica charantia (MC) and Eugenia jambolana (EJ) have been shown to reduce hyperglycemia in diabetic animal models and human patients. However, no work has been done so far to assess their effect on insulin resistance. This study was undertaken to study the effects of different doses (100,200 and 400 mg per day) of alcoholic and aqueous extracts of MC and EJ on the metabolic parameters (body weight and serum glucose, insulin and triglycerides levels) of fructose fed rats. Fructose feeding for 15 days increased serum glucose and insulin levels markedly and triglycerides levels marginally vs. control (75.46+/-2.41 vs. 55.59+/-2.89 mg/dl, 6.26+/-1.27 vs. 15.04+/-2.43 mg/dl and 50.93+/-3.30 vs.41.1+/-3.33 mg/dl, respectively). Treatment with 400 mg per day of aqueous extracts of MC and EJ for 15 days substantially prevented hyperglycemia and hyperinsulinemia induced by a diet high in fructose (63.52+/-2.9 and 66.46+/-2.2 vs. 75.46+/-2.4, respectively).

Analysis of Variance↗

Fulminant radiation-induced necrosis after stereotactic radiation therapy to the posterior fossa. Case report and review of the literature.

The problem of radiation-induced necrosis of normal brain surrounding the target area has been a major catalyst for the development of stereotactically focused radiation therapy. According to current opinion, the effects of stereotactic irradiation are confined to the region targeted. The authors present a case in which the administration of a conventional dose of stereotactically focused irradiation for treatment of a pilocytic astrocytoma produced fulminant necrosis that necessitated a combination of intensive surgical and medical management, after which the patient improved over the course of 1 year. Concomitant with his improvement, the initially remarkable findings on magnetic resonance imaging gradually resolved. In this presentation the authors emphasize the need to evaluate alternatives carefully before a decision is made to administer therapeutic irradiation. Furthermore, they explore the roles that target, host, and dosage factors play in hypersensitivity to radiation injury, the detection of these factors before treatment, and the administration of radioprotective agents. With the growing use of stereotactically focused irradiation as a primary treatment modality for a variety of neurosurgical conditions, it is important to be cognizant of its uncommon but potentially lethal side effects. A cooperative multicenter database in which the outcomes and morbidity following stereotactic irradiation are recorded is essential to the detection of relatively uncommon but severe complications such as those observed in this case.

Adult↗

Target gland functional status in patients with non-Cushing's pituitary macroadenomas undergoing transsphenoidal microsurgery.

OBJECTIVES: Hypopituitarism occurring in patients with pituitary macroadenoma may be reversible after pituitary microsurgery, and surgery itself can lead to hypopituitarism. This study was undertaken to evaluate target gland function prospectively in patients of non-Cushing's pituitary macroadenoma undergoing trans-sphenoidal microsurgery. MATERIAL AND METHODS: A prospective study of fifty patients of non-Cushing's pituitary adenoma was carried out to evaluate target gland (thyroid, adrenal and gonadal) undergoing trans-sphenoidal microsurgery. Thirty-two patients completed postoperative evaluation before radiotherapy. Target gland functions were assessed by measurement of T3, T4, TSH, basal and stimulated cortisol, LH, FSH, testosterone and estradiol. GH and PRL were also measured. Tumor size was assessed on CT/MRI scan. RESULTS: Hypothyroidism, hypoadrenalism and hypogonadism were present in 24%, 54% and 52% of patients. Preoperative hypopituitarism correlated with tumour size. Thyroid, adrenal and gonadal function improved in 87%, 50% and 31%; deteriorated in 4%, 29%, and 37%, respectively after trans-sphenoidal microsurgery. CONCLUSIONS: A subset of patients with non-Cushing's pituitary macroadenoma suffers from hypopituitarism, which reverses after surgery. Failure of recovery correlates with preoperative lower serum prolactin levels.

Adenoma↗

Interventional therapy for acute myocardial infarction.

Percutaneous transluminal coronary angioplasty has proven to be more effective and safer than thrombolytic therapy for the treatment of acute ST elevation myocardial infarction. Coronary intervention decreases early mortality and the incidence of intracerebral hemorrhage when performed by an experienced interventional team in a timely fashion. After failed fibrinolytic therapy for myocardial infarction, percutaneous transluminal coronary angioplasty is indicated for signs of ischemia and is very effective in restoring vessel patency and reducing mortality when used as a rescue procedure. The glycoprotein IIb-IIIa inhibitors improve outcomes in percutaneous transluminal coronary angioplasty, particularly in patients undergoing stent placement. Percutaneous interventional therapy in acute myocardial infarction is particularly beneficial in patients with cardiogenic shock and effective for saphenous vein graft occlusions, patients with diabetes mellitus, and in the elderly. New devices and drugs are currently being tested for acute myocardial infarction and provide hope for even better interventional therapies in the near future.

Angioplasty, Balloon, Coronary↗

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↗