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Biomedical subjects

Surjit Singh

Publications and source records attributed to Surjit Singh.

At least 19 recordsLinked to original sources

Acute tubulo-interstitial nephritis leading to acute renal failure following multiple hornet stings.

BACKGROUND: Hornet stings are generally associated with local and occasionally anaphylactic reactions. Rarely systemic complications like acute renal failure can occur following multiple stings. Renal failure is usually due to development of acute tubular necrosis as a result of intravascular haemolysis, rhabdomyolysis or shock. Rarely it can be following development of acute tubulo-interstitial nephritis. CASE PRESENTATION: We describe a young male, who was stung on face, head, shoulders and upper limbs by multiple hornets (Vespa orientalis). He developed acute renal failure as a result of acute tubulo-interstitial nephritis and responded to steroids. CONCLUSION: Rare causes of acute renal failure like tubulo-interstitial nephritis should be considered in a patient with persistent oliguria and azotemia following multiple hornet stings. Renal biopsy should be undertaken early, as institution of steroid therapy may help in recovery of renal function.

Acute Disease↗

Study of subcutaneous fat in children with juvenile dermatomyositis.

OBJECTIVE: Lipodystrophy is a recently recognized complication of juvenile dermatomyositis (juvenile DM). Until now, the diagnosis has been based only on the physical appearance of the patient. We quantified the patterns of fat distribution in a cohort of patients with juvenile DM. METHODS: Twenty patients with juvenile DM were enrolled along with a matching number of controls. Both groups underwent standard anthropometric measurements including assessment of skinfold thickness using Harpenden Skinfold Caliper (Holtain, Dyfed, UK). Glucose tolerance test and serum lipid estimates were performed in the study group but not in controls. RESULTS: Patients with juvenile DM had lower mean weight, height, and mid-upper-arm circumference as compared with controls; these differences were statistically significant (P < or = 0.05). Eight (40%) of 20 patients had lipodystrophy on physical appearance. When assessed by skinfold caliper, there was loss of subcutaneous fat at the mid-axillary site in 65% of patients, at the subscapular in 60%, and at the suprailiac site in 55%. Serum triglyceride levels were increased in 12 of the 18 patients who underwent this test. Oral glucose tolerance test results were normal in all 20 patients. CONCLUSION: Sixty-five percent of our patients with juvenile DM were found to have loss of subcutaneous fat on quantification compared with 40% on physical appearance alone. Maximum fat loss occurred at the mid-axillary skinfold site. A significant number of patients with juvenile DM (66%) had hypertriglyceridemia. We hypothesize that lipodystrophy and hypertriglyceridemia could well be integral components of what may be an expanded juvenile DM syndrome.

Adipose Tissue↗

Immune responses in patients with HIV infection after vaccination with recombinant Hepatitis B virus vaccine.

BACKGROUND: Patients with HIV infection are at risk of co-infection with HBV, as the routes of transmission are shared and thus immunization with HBV vaccine could be protective in them. The aim of the present study was to assess the efficacy of recombinant vaccine in treatment-naive HIV positive patients and healthy controls, and to dissect out differences if any, in different limbs of immune response. METHODS: Forty HIV positive patients and 20 HIV negative controls, negative for HBsAg, HBsAbs and HBcAbs were vaccinated with three doses of 40 microg and 20 microg of vaccine respectively. Patients were divided into high CD4 and low CD4 group based on CD4+ lymphocytes of 200 and < 200/mm3 respectively. Group II consisted of healthy controls. Detection of phenotypic markers was done by flowcytometry. Cytokine estimation was done by sandwich ELISA. HBsAbs were estimated in serum by ELISA. RESULTS: After vaccination, CD4+, CD8+ and CD3+ cells increased significantly in all the groups. There was no increase in NK cell activity in patients with high CD4+ lymphocytes and only a marginal increase in patients with low CD4+ lymphocytes (170 to 293/mm3) whereas a marked increase was observed in controls (252 to 490/mm3). After vaccination, although an increase in memory cells was observed in HIV positive patients, yet HBsAb levels were significantly lower than controls (P < 0.05) indicating a functional defect of memory cells in HIV/AIDS patients. Basal IFN-gamma levels were also significantly lower in HIV/AIDS patients (P < 0.01). Although the levels increased after vaccination, the peak level remained lower than in controls. HBsAb titers were much lower in HIV positive patients compared to controls. (High CD4+ group: 8834 mIU/ml, low CD4+ group: 462 mIU/ml Vs. CONTROLS: 16,906 mIU/ml). IL-4 and IL-10 were low in patients. CONCLUSION: Despite a double dose in patients, IL-4 and IL-10, which regulate antibody response, were also lower in patients, and this together with low CD4+ counts and lack of T help, accounted for low HBsAb levels. Vaccination in patients with CD4+ lymphocytes < 50/mm3 was ineffective. Thus early immunization is advocated in all HIV positive patients at a stage when they are still capable of mounting an adequate immune response.

Acquired Immunodeficiency Syndrome↗

Purification and characterization of neuropathy target esterase (NTE) from rat brain.

Neuropathy target esterase (NTE) is an integral membrane protein in vertebrate neurons and a member of a novel family of putative serine hydrolases. Neuropathic organophosphates react covalently with the active site serine residue of NTE, causing degeneration of long axons in spinal cord and peripheral nerves which becomes clinically evident 1-3 weeks after exposure to OPs, hence termed as organophosphate induced delayed neuropathy. The present study reports the isolation and characterization of NTE protein from rat brain. Rat brain microsomes were solubilized with phospholipase A2 and they were fractionated by gel filtration chromatography in S-300 column. The sample was eluted in buffer containing polyoxyethylene W1 detergent, which yielded an active fraction of 200 kDa. The most enriched NTE active fraction was further purified by 3-9'-mercaptononylthio-1,1,1-trifluoropropan-2-one bound to sepharose CL4B. The SDS-PAGE confirmed the 155-kDa protein as the most likely candidate for NTE. Database searching of rat N-terminal protein revealed homology with variety of polypeptides from different organisms and suggested that NTE protein has function beyond the nervous system and mediates a biochemical reaction highly conserved through evolution.

Amino Acid Sequence↗

Childhood lupus nephritis: 12 years experience from North India.

Twenty-five children (20 girls and five boys) with lupus nephritis seen over last 12 years, were evaluated. Twenty underwent renal biopsies. Cyclophosphamide pulse therapy was used in eight patients (median 14 pulses, range 6-16) with severe disease or histological class. Four of these eight patients became asymptomatic (class IV, 2; class II and V, one each) after 4-24 months. Two (class III and IV, one each) died after a stable chronic renal insufficiency for almost a decade; one died 9 months after diagnosis (class IV). Of the 12 patients who underwent biopsy but were not treated with cyclophosphamide, six became asymptomatic during follow up (class II, four patients; class VI and V, one each), two continued to have proteinuria (class II), one (class IV) had raised ESR but normal renal functions and two died (class IV). Three of the five patients who were not biopsied remained asymptomatic; two were lost to follow up. Mortality was seen only with class III (one patient) or class IV (five patients) lesions. Outcome in lupus nephritis depends largely on WHO histological class. Cyclophosphamide pulse therapy is associated with a favorable outcome.

Child↗

Cytochrome-c oxidase inhibition in 26 aluminum phosphide poisoned patients.

INTRODUCTION: Aluminum phosphide (ALP) is used worldwide to fumigate grain. ALP poisoning, though reported from different parts of world, is most common in north, northwest and central India. In the presence of moisture, ALP liberates phosphine, which is highly toxic. The mechanism of action of phosphine is not known though experimental studies show that it inhibits cytochrome-c oxidase leading to inhibition of mitochondrial oxidative phosphorylation. PATIENTS AND METHODS: We estimated cytochrome-c oxidase activity in platelets of patients who had ingested ALP and compared them with those in healthy controls and in patients with shock due to other causes (cardiogenic shock, septic shock and hemorrhagic shock). RESULTS: After analysis of variance using Kruskal-Wallis test followed by Mann Whitney U test, significant inhibition of cytochrome-c oxidase activity could be found in ALP-poisoned patients compared to healthy controls (z = -5.513, p < 0.001) and in patients with shock due to other causes (z = -2.344; p < 0.05). There was no significant difference in inhibition in those who survived ALP poisoning compared to those who died from ALP poisoning (t = 0.02768; p > 0.05). CONCLUSION: Though inhibition of cytochrome-c oxidase in platelets does not have prognostic value, it suggests that interruption of mitochondrial oxidative phosphorylation as a result of cytochrome-c oxidase inhibition may lead to multi-organ dysfunction and therapeutic strategies to maintain enzyme activity may help in managing these patients.

Adolescent↗

Twelve years experience of juvenile dermatomyositis in North India.

The aim of this study was to evaluate outcome in children with juvenile dermatomyositis (JDMS) at a tertiary care center in North India and have a long term follow-up. Medical records of children with JDMS managed at a tertiary care hospital were reviewed during a 13-year period to determine (1) interval between onset of symptoms and diagnosis, (2) treatment modalities used and (3) long term functional outcome. Thirty three patients diagnosed with JDMS met the inclusion criteria. Mean age at diagnosis was 8.7 +/- 3.3 years. Mean duration of disease prior to treatment was 1.18 years (range 1 month-5 years). The total follow-up period was 136.7 patient-years. Immunosuppressive therapy was given in 31/33 and a distinct monocyclic course was seen in 72.7% cases. Lipodystrophy was seen in 10/33 (30.3%), calcinosis in 7/33 (27.3%), cutaneous ulcers in 6/33 (18.2%), dysphagia in 5/33 (15.2%), and contractures in 4/33 (12.1%) cases. A steady and sustained response was seen in patients who had received "adequate" doses of steroids at the time of initiation of treatment. Methotrexate, hydroxychloroquine, azathioprine and intravenous immunoglobulin were used in patients with poor response to corticotherapy. There were two deaths in our series. Stepwise, aggressive treatment directed at achieving rapid and complete control of muscle inflammation is highly successful in minimizing the long-range sequelae of JDMS. Our patients seem to have a different clinical profile on follow-up as compared to series published from the West.

Adolescent↗

Kawasaki disease: a decade of experience from North India.

Kawasaki disease (KD) has not been frequently reported from developing countries, especially from India. In this series from a tertiary level center in North India, we report on the clinical features and management of patients with KD seen between January 1994 to November 2004. KD was diagnosed on the basis of standard diagnostic criteria. Investigations included work-up for other causes of fever along with chest X-rays, electrocardiograms, and 2-D echocardiography. Thallium scintigraphy and coronary angiography were performed in 20 and 3 cases, respectively. Sixty-nine children (49 boys and 20 girls) fulfilled the diagnostic criteria. Mean age at diagnosis was 4.9 +/- 3.0 years (range 0.3-14 years) and as many as 23 cases (33.3%) were above 5 years of age. Clustering was seen during the winter months. Extreme irritability, out of proportion to the degree of fever, was a characteristic feature. Redness of the lips and tongue was common but rash was seen only in 43 cases and lymphadenopathy in 47 cases. Thrombocytosis was present in 52.2% of the patients. Sixty-four patients received intravenous immunoglobulin. Cardiac abnormalities included extrasystoles in 1, coronary artery dilatation in 5, valvular regurgitation in 3, and perfusion defects on thallium scintigraphy in 4. There was no mortality. KD appears to occur at an older age in Indian children as compared to reports from Japan. Irritability is a characteristic clinical finding. Cardiac abnormalities are frequent during the acute stage but regress gradually. The disease needs to be considered in the differential diagnosis of all children with persistent unexplained fever.

Adolescent↗

Serum lipids in north Indian children treated for kawasaki disease.

A prospective cross sectional analysis of serum lipids was carried out in 20 children aged between 1.3 and 16 years with Kawasaki disease (KD). The controls were siblings of other patients. The mean interval between diagnosis of the disease and time of assay was 2.6 years (range 0.41 to 6 years). Standard biochemical methods were employed for determination of various components of the lipid profiles. There were significant differences in high-density lipoprotein cholesterol (HDL-C) (40.37 +/- 12.0 mg/dL versus 53.49 +/- 4.31 mg/dL, P < 0.001) and low-density lipoprotein cholesterol (LDL-C) concentrations (77.76 +/- 26.25 mg/dL versus 57.7 +/- 23.2 mg/dL, P < 0.05) between the cases and controls. Lower HDL-C levels persisted at 1-3 and more than 3 years of disease duration. No significant differences were seen in the values of other parameters in the lipidogram, such as total cholesterol (TC), triglycerides (TG), and very low-density lipoprotein cholesterol (VLDL-C). Premature atherosclerosis that occurs in KD may be secondary to these lipid metabolism abnormalities.

Adolescent↗

Antiphospholipid antibodies in children with systemic lupus erythematosus: a prospective study in northern India.

Twenty-seven children with systemic lupus erythematosus (SLE) were tested for antiphospholipid antibodies (APLA), i.e. lupus anticoagulant and immunoglobulin (Ig)G or IgM anticardiolipin antibodies (ACLA), with beta-2 glycoprotein I as cofactor, in a single-centre, prospective study over 2 years. Eighteen patients (67%) tested positively for one or the other APLA during the course of the study. Twelve children (44%) tested positively for IgG ACLA and ten (37%) for IgM ACLA, whereas eight (30%) were positive for lupus anticoagulant. In two patients with thrombosis, IgG anticardiolipin positivity was seen to be variable. Unlike the results of most other reports in the literature, lupus anticoagulant positivity was not consistently associated with thrombosis. A majority of the children (83%) tested positively for ACLA during disease activity. Immunoglobulin G and IgM ACLA positivity did not correlate significantly with disease status. The results of this prospective study would indicate that, though frequently present, APLA may be unable to be predictive of disease behaviour in children with SLE.

Adolescent↗

Varicella glomerulonephritis mimicking microscopic polyangiitis.

Varicella in childhood is usually a self-limiting illness with few complications. Varicella nephritis is an uncommon entity and seen mostly in immunocompromized individuals. We report a 14-year-old boy with juvenile rheumatoid arthritis who developed varicella nephritis and in whom the renal manifestations preceded the skin lesions by 1 week. This is an extremely unusual occurrence, and only one case has been described before. Such a presentation can mimic the clinical features of microscopic polyangiitis.

Adolescent↗

A novel thermodynamic relationship based on Kramers Theory for studying enzyme kinetics under high viscosity.

In most studies of enzyme kinetics it has been found sufficient to use the classical Transition State Theory (TST) of Eyring and others. This theory was based on the solvent being an ideal dilute substance treated as a heat bath. However, enzymes found in organisms adapted to very low (psychrophiles) and very high (thermophiles) temperatures are also subjected to variable solute concentrations and viscosities. Therefore, the TST may not always be applicable to enzyme reactions carried out in various solvents with viscosities ranging from moderate to very high. There have been numerous advances in the theory of chemical reactions in realistic non-ideal solvents such as Kramers Theory. In this paper we wish to propose a modified thermodynamic equation, which have contributions from kcat, Km and the viscosity of the medium in which the enzyme reaction is occurring. These could be very useful for determining the thermodynamics of enzymes catalyzing reactions at temperature extremes in the presence of substrate solutions of different compositions and viscosities.

Catalysis↗