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Biomedical subjects

S K Singh

Publications and source records attributed to S K Singh.

At least 19 recordsLinked to original sources

Presentation and outcome of emphysematous renal tract disease in patients with diabetes mellitus.

BACKGROUND: Emphysematous renal tract disease (ERTD) is a rare necrotizing infection of the renal parenchyma and urinary tract caused by gas-producing organisms. ERTD deserves special attention because of its life-threatening potential. OBJECTIVES: To study the clinical features, radiological classification and prognostic factors of ERTD; and to compare the modalities of management and the outcome among the various radiological classes of ERTD. PATIENTS AND METHODS: Twenty consecutive patients with diabetes and ERTD, seen over last 3 years in a tertiary care institute of north India, were included in the study. All patients were subjected to computerized tomography (CT) after initial diagnosis by ultrasonography. They were classified into 5 classes as previously described. All patients included in the study were conservatively managed with appropriate antibiotics and/or percutaneous drainage or surgery if required. RESULT: Mean age (+/- SD) of these subjects was 54.4 +/- 20.6 years; duration of diabetes mellitus 8.6 +/- 5.8 years, and duration of symptoms related with ERTD ranged from 3 days to 3 months. Two patients had isolated emphysematous cystitis, 13 patients had emphysematous pyelonephritis (EPN), 3 had both EPN and cystitis, and 1 patient had EPN with cholecystitis, and 1 patient had EPN with pyomyositis. Only 7 (35%) patients had a history of pneumaturia. Escherichia coli was the commonest microorganism. The radiological distribution in 18 (2 had isolated cystitis) patients with EPN was: 2 patients had class 1; 1 had class 2; 2 had class 3A; 11 had class 3B, and 2 had class 4. Of 20 patients 11 (55%) survived. However, those patients who died had severe EPN based on radiological class (6 had class 3B and 1 had class 4). There was no significant difference between the survivor and non-survivor groups with respect to age, gender, duration of diabetes mellitus, duration of symptoms, serum creatinine level, total leukocyte count, hemoglobin, platelet count and culture positivity. CONCLUSION: Computerized tomographic class 3B or 4 is the most reliable predictor of outcome in patients with ERTD.

Adult↗

Impact of degradation on nitrogen transformation in a forest ecosystem of India.

A study was performed selecting one protected forest and an adjacent degraded forest ecosystem to quantify the impact of forest degradation on soil inorganic nitrogen, fine root production, nitrification, N-mineralization and microbial biomass N. There were marked seasonal variations of all the parameters in the upper 0-10 and lower 10-20 cm depths. The seasonal trend of net nitrification and net N-mineralization was reverse of that for inorganic nitrogen and microbial biomass N. Net nitrification, net N-mineralization and fine root biomass values were highest in both forests during rainy season. On contrary, inorganic nitrogen and microbial biomass N were highest during summer season.There was a marked impact of forest degradation on inorganic nitrogen, fine root production nitrification, N-mineralization and microbial biomass observed. Soil properties also varied with soil depth. Fine root biomass, nitrification, N-mineralization and microbial biomass N decreased significantly in higher soil depth. Degradation causes decline in mean seasonal fine root biomass in upper layer and in lower depth by 37% and 27%, respectively. The mean seasonal net nitrification and N-mineralization in upper depth decreased by 42% and 37%, respectively and in lower depth by 42.21% and 39% respectively. Similarly microbial biomass N also decreased by 31.16% in upper layer 33.19% in lower layer.

Ammonia↗

3D-QSAR CoMFA study on indenopyrazole derivatives as cyclin dependent kinase 4 (CDK4) and cyclin dependent kinase 2 (CDK2) inhibitors.

Cyclin dependent kinases (CDKs) have appeared as an important drug targets over the years with diverse therapeutic potentials. With the objective of designing new chemical entities with enhanced inhibitory potencies against CDK 2 (CDK2) and CDK 4 (CDK4), the 3D-QSAR CoMFA study carried out on indenopyrazole derivatives as inhibitors of these kinases is presented here. The developed model showed a strong correlative and predictive capability having a cross validated correlation co-efficient of 0.747 for CDK4 and 0.755 for CDK2 inhibitions. The conventional and predictive correlation co-efficients were, respectively, found to be 0.913 and 0.760 for CDK4, 0.941 and 0.765 for CDK2. The models could be employed to design ligands with enhanced inhibitory potencies and/or to predict the potencies of analogues to guide synthesis.

Cyclin-Dependent Kinase 2↗

Nuclear effects in neutrino induced coherent pion production at K2K and MiniBooNE.

The coherent pion production induced by neutrinos in nuclei is studied using a delta hole model in the local density approximation taking into account the renormalization of Delta properties in a nuclear medium. The pion absorption effects are included in an eikonal approximation. These effects give a large reduction in the total cross section. The numerical results for the total cross section are found to be consistent with recent experimental results from the K2K and MiniBooNE Collaborations and other older experiments in the intermediate energy region.

Journal Article↗

AXR4 is required for localization of the auxin influx facilitator AUX1.

The AUX1 and PIN auxin influx and efflux facilitators are key regulators of root growth and development. For root gravitropism to occur, AUX1 and PIN2 must transport auxin via the lateral root cap to elongating epidermal cells. Genetic studies suggest that AXR4 functions in the same pathway as AUX1. Here we show that AXR4 is a previously unidentified accessory protein of the endoplasmic reticulum (ER) that regulates localization of AUX1 but not of PIN proteins. Loss of AXR4 resulted in abnormal accumulation of AUX1 in the ER of epidermal cells, indicating that the axr4 agravitropic phenotype is caused by defective AUX1 trafficking in the root epidermis.

2,4-Dichlorophenoxyacetic Acid↗

Differential expression patterns of recombination-activating genes in individual mature B cells in juvenile idiopathic arthritis.

BACKGROUND: Re-expression of the recombination-activating genes (RAG) in peripheral B cells may be relevant in the development of autoreactive antibodies in autoimmune diseases. The presence of antinuclear antibodies (ANA) as a hallmark of oligoarticular juvenile idiopathic arthritis (o-JIA, early-onset type) indicates a breakdown in immunological tolerance. AIM: To examine the expression of RAG genes in peripheral blood mature B lymphocytes in patients with o-JIA. METHODS: 777 memory B cells from peripheral blood, CD19+ CD27+ CD5+ or CD19+ CD27+ CD5-, isolated from three ANA+ children with o-JIA and three healthy age-matched children, were examined for the expression of RAG1 and RAG2 mRNA. mRNA transcripts of activation-induced cytidine deaminase and immunoglobulin G were searched to further determine their developmental stage. RESULTS: mRNA was present for any of the two RAG genes in the B cells of children with JIA and controls. However, the predominance of RAG1 or RAG2 was different. A significantly decreased frequency of RAG2-expressing memory B cells in both CD5+ and CD5- populations was noted in children with JIA (p<0.001), whereas the number of RAG1-expressing B cells was slightly increased. The coordinate expression of both the RAG genes was a rare event, similar in the CD5+ populations (1% in controls, 2% in children with JIA), but different among the CD5- compartments (5% v 0%; p<0.01). CONCLUSION: These results argue for a reduced coordinate RAG expression in the peripheral CD5- memory B cells of patients with o-JIA. Thus, it was hypothesised that impaired receptor revision contributes to autoimmune pathogenesis in JIA.

Arthritis, Juvenile↗

The retrograde nail for distal femoral fractures in the elderly: high failure rate of the condyle screw and nut.

Displaced distal femoral fractures in elderly patients benefit from surgical fixation. We describe the use of a retrograde femoral nail to treat these fractures. The implant has a special condyle screw and nut that allows for manual compression of the fracture when there is an additional inter-condylar split. We present our results when using this implant to treat 16 patients over a 13-month period. The mean patient age was 78 years (range, 65-96 years). All 16 patients were available at the time of final follow up and proceeded to union at an average time of 11 weeks (range, 10-14 weeks). Twenty-six condyle screw and nuts were used. Ten out of 26 condyle screws in 10 out of 16 patients failed by disengaging at a mean time of 10 weeks (range, 8-12 weeks). Our union rate was unaffected by the nut and bolt disengaging. This would suggest that the condylar compression generated by the nut and bolt may not be critical for union.

Age Factors↗

Lithogenesis: induction of renal calcifications by nanobacteria.

Nanobacteria have been isolated from kidney stones and it has been suggested that they may act as a nucleus for the initiation of the renal stones. In the present study, we examine their role in biocrystallization and their in vivo effects on kidney pathology. Calcium oxalate monohydrate (COM) assay was carried out in the presence of nanobacteria to study biocrystallization. Wistar rats were given an intravenous injection of nanobacteria and the kidneys were examined for pathological changes. The COM assay showed accelerated biocrystallization of (14)C-oxalate in the presence of nanobacteria, indicating them to be efficient candidates for biomineralization. Histopathological studies revealed bacteria induced renal tubular calcifications and various manifestations of infection. Our studies confirm that nanobacteria may be involved in the pathogenesis of renal tubular calcification.

Animals↗

Treatment of oropharyngeal cancer in renal transplant recipients without cessation of immunosuppressive therapy.

INTRODUCTION: Renal transplantation and immunosuppression are associated with an increased incidence of malignancy. Reduction or cessation of immunosuppressive therapy has been advocated in these cases to prevent tumor progression and recurrence. We evaluated the outcome of treatment of oropharyngeal cancer (OC) after renal transplantation without cessation of immunosuppressive therapy. METHODS: The database of patients with OC after renal transplantation was analyzed with respect to age, sex, type of immunosuppression, interval between transplantation and diagnosis of cancer, as well as method of treatment and survival. RESULTS: Thirty one (2.06%) renal transplant recipients developed malignancy including 6 (20%) with OC. Lingual cancer was seen in three, and one each showed an isolated tonsillar lymphoma, a parotid carcinoma, or a carcinoma of the larynx with only the last having had two other malignancies in the past. Three subjects were on immunosuppression with azathioprine and prednisolone, and the others were prescribed cyclosporine and prednisolone. Average time from transplantation to diagnosis of OC was 106 months. The interval was the shortest (2 years) for tonsillar lymphoma in an 18-year-old patient who received cyclosporine and showed features of left follicular tonsillitis. The patient with advanced carcinoma of the larynx did not receive any treatment and succumbed within 3 months. The dose of cyclosporine was reduced in the lymphoma case but immunosuppression was not altered in the other patients. All subjects were treated with a standard protocol. During a mean follow-up of 33 months, one had local recurrence of parotid carcinoma and the others showed well functioning renal grafts. CONCLUSION: Comprehensive treatment of OC after renal transplantation without withdrawing the immunosuppression prolonged the life of these patients with functioning grafts.

Adolescent↗

Challenging and changing gender attitudes among young men in Mumbai, India.

This article presents findings from a pilot intervention in 2005-6 to promote gender equity among young men from low-income communities in Mumbai, India. The project involved formative work on gender, sexuality and masculinity, and educational activities with 126 young men, aged 18-29, over a six-month period. The programme of activities was called Yari-dosti, which is Hindi for friendship or bonding among men, and was adapted from a Brazilian intervention. Pre- and post-intervention surveys, including measures of attitudes towards gender norms using the Gender Equitable Men (GEM) Scale and other key outcomes, qualitative interviews with 31 participants, monitoring and observations were used as evaluation tools. Almost all the young men actively participated in the activities and appreciated the intervention. It was often the first time they had had the opportunity to discuss and reflect on these issues. The interviews showed that attitudes towards gender and sexuality, as reported behaviour in relationships, had often changed. A survey two months later also showed a significant decrease in support for inequitable gender norms and sexual harassment of girls and women. The results suggest that the pilot was successful in reaching and engaging young men to critically discuss gender dynamics and health risk, and in shifting key gender-related attitudes.

Adolescent↗

Preoperative embolization of a large vaginal leiomyoma: report of a case and review of the literature.

Leiomyoma of the vagina is a very rare tumour of the lower urogenital tract. These slow-growing masses may be asymptomatic or present with pain, dyspareunia or urinary symptoms. Rarely, these tumours may present with life-threatening haemorrhage. These hypervascular tumours are treated by surgical excision. Preoperative embolization therefore may aid in devascularization of these tumours before surgical excision. We present the MRI features of a case of vaginal leiomyoma, which was managed by preoperative embolization and was then excised in toto. To the best of our knowledge, this is the first report where preoperative embolization was performed before excision of a vaginal leiomyoma with minimal peroperative blood loss.

Adult↗

Toll-like receptors in Borrelia burgdorferi-induced inflammation.

Lyme arthritis, the most common manifestation of late Lyme disease, has been associated with the presence of Borellia burgdorferi in the joint. However, it is still unclear whether the pathogen itself is able to elicit such a sustained inflammatory response, or whether an aberrant immunological reaction of the host is the main driving force. Borrelia antigens, including lipoproteins, flagellin and DNA, are ligands of Toll-like receptors, and can thus elicit a strong stimulation of host cells, such as neutrophils, mononuclear cells and resident tissue cells. Understanding the molecular basis of the signalling events caused by Borrelia lipoproteins will lead to a greater understanding of inflammation in Lyme arthritis and, hopefully, new treatment strategies for chronic antibiotic-resistant disease.

Animals↗

Pre- & post-treatment evaluation of immunological features in Indian visceral leishmaniasis (VL) patients with HIV co-infection.

BACKGROUND & OBJECTIVE: The risk of human immunodeficiency virus (HIV) co-infection in patients with visceral leishmaniasis (VL) or kala-azar in endemic areas has posed a major challenge in control programmes. We undertook this study to identify the high risk groups vulnerable to Leishmania-HIV co-infection in VL endemic State of Bihar, India. Further, immunological responses were also evaluated in these patients before and after treatment for VL to see the immune impairment associated with CD4 T cell count. METHODS: A total of 1511 subjects attending Voluntary Counselling and Testing Centre (VCTC) at Patna, Bihar were included in this study. VL was confirmed by splenic or bone marrow aspirates testing for parasite. HIV states was confirmed by two kits. Immunological parameters (CD4, CD8, IFN-gamma, IL-4) were studied in co-infection patients. RESULTS: Of the 280 (18.53%) HIV-positive individuals, eight were diagnosed serologically and pathologically as VL patients co-infected with HIV. The humoral and cellular immune responses were evaluated in 18 Indian VL patients with (n = 8) or without HIV (n = 10) and 10 HIV seropositive subjects. Among the eight confirmed cases of VL, false negative direct agglutination test (DAT) result was observed in two who had HIV co-infection (sensitivity 80%), while none in 10 other VL cases who were HIV negative (sensitivity 100%). A very low CD4 cell count was observed in VL cases that had HIV co-infection compared to HIV negative VL or controls. All VL cases with or without HIV infection had lower Th1/Th2 ratio compared to controls. VL patients with or without HIV infection responded well to anti-leishmanial/anti-retroviral therapy with considerable degree of immunological reconstitution. INTERPRETATION & CONCLUSION: A different immune response was noticed in patients with co-infection of HIV and Leishmania. Anti-leishmanial drug treatment led to improvement in immunological response in co-infected patients. Further studies need to be done to see the effect of combined therapy for VL and HIV on immunological parameters in these patients.

Adolescent↗

Does Paget's disease exist in India?: A series of 21 patients.

OBJECTIVE: Paget's disease of bone has been described as a few case reports from India. The aim of the present study is to document the existence of Paget's disease (PD) in India. MATERIAL AND METHODS: We describe demography, clinical manifestations, biochemical and radiological profile and the treatment outcome of 21 patients of PD. RESULTS: Mean (+/-SD) age of these patients at presentation was 49.2 +/- 17.6 years and the male to female ratio was 2.5:1. Common clinical manifestations included backache, headache and bone pains. Others were fracture, joint pain, deafness, gait ataxia, visual impairment and difficulty in biting. Two patients presented with hydrocephalus and one had recurrent paraparesis. Fifteen (71.4%) patients had polyostotic and six (28.6%) had monoostotic Paget's disease. More commonly involved bones were skull and spine (61.9%) followed by pelvis (38.1%), femur (33.3%), tibia (9%) and ulna (9%). Mean (+/-SD) serum alkaline phosphatase at diagnosis was 1514 +/- 1168 IU/L and nine months after treatment with bisphosphonates decreased to 454 +/- 406 IU/ L(P<0.03). CONCLUSION: This illustrates that Paget's disease does exist in India and a high index of suspicion is required to clinch the diagnosis.

Absorptiometry, Photon↗