Minimal change disease and Hodgkin's disease: a rare association.
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Child↗
Biomedical subjects
S Gulati
Publications and source records attributed to S Gulati.
Binding of complement factor H to loop 5 of porin protein 1A: a molecular mechanism of serum resistance of nonsialylated Neisseria gonorrhoeae.
Neisseria gonorrhoeae isolated from patients with disseminated infection are often of the porin (Por1A) serotype and resist killing by nonimmune normal human serum. The molecular basis of this resistance (termed stable serum resistance) in these strains has not been fully defined but is not related to sialylation of lipooligosaccharide. Here we demonstrate that Por1A bearing gonococcal strains bind more factor H, a critical downregulator of the alternative complement pathway, than their Por1B counterparts. This results in a sevenfold reduction in C3b, which is >75% converted to iC3b. Factor H binding to isogenic gonococcal strains that differed only in their porin serotype, confirmed that Por1A was the acceptor molecule for factor H. We identified a surface exposed region on the Por1A molecule that served as the binding site for factor H. We used gonococcal strains with hybrid Por1A/B molecules that differed in their surface exposed domains to localize the factor H binding site to loop 5 of Por1A. This was confirmed by inhibition of factor H binding using synthetic peptides corresponding to the putative exposed regions of the porin loops. The addition of Por1A loop 5 peptide in a serum bactericidal assay, which inhibited binding of factor H to the bacterial surface, permitted 50% killing of an otherwise completely serum resistant gonococcal strain. Collectively, these data provide a molecular basis to explain serum resistance of Por1A strains of N. gonorrhoeae.
Amino Acid Sequence↗
Disruption of a regulatory system involving cobalamin distribution and function in a methionine-dependent human glioma cell line.
Cobalamin metabolism and function were investigated at the levels from transcobalamin II (TCII) receptor to the cobalamin-dependent enzymes, methionine synthase and methylmalonyl-CoA mutase, in a methionine-dependent (P60) and a methionine-independent (P60H) glioma cell line. Using P60H as reference, the P60 cells cultured in a methionine medium had slightly lower TCII receptor activity and normal total cobalamin content, a moderately reduced microsomal and mitochondrial cobalamin(III) reductase activity but only trace amounts of the methylcobalamin and adenosylcobalamin cofactors. When transferred to a homocysteine medium without methionine, P60H cells showed a slightly enhanced TCII receptor activity, but the other cobalamin-related functions were essentially unchanged. In contrast, the methionine-dependent P60 cells responded to homocysteine medium with a nearly 6-fold enhancement of TCII receptor expression and a doubling of both the hydroxycobalamin content and the microsomal reductase activity. The mitochondrial reductase and the cobalamin-related processes further down the pathway did not change markedly. In both cell lines, TCII receptor activity was further increased when growth in homocysteine medium was combined with N2O exposure. These data suggest that low methionine and/or high homocysteine exert a positive feedback control on TCII receptor activity. The concurrent increase in hydroxycobalamin content and in microsomal reductase activity are either subjected to similar regulation or secondary to increased cobalamin transport. This regulatory network is most prominent in the methionine-dependent P60 cells harboring a disruption of the network in the proximity of cobalamin(III) reductase.
5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
A novel sialic acid binding site on factor H mediates serum resistance of sialylated Neisseria gonorrhoeae.
Factor H (fH), a key alternative complement pathway regulator, is a cofactor for factor I-mediated cleavage of C3b. fH consists of 20 short consensus repeat (SCR) domains. Sialic acid binding domains have previously been localized to fH SCRs 6-10 and 13. To examine fH binding on a sialylated microbial surface, we grew Neisseria gonorrhoeae in the presence of 5'-cytidinemonophospho-N-acetylneuraminic acid, which sialylates lipooligosaccharide and converts to serum resistance gonococci previously sensitive to nonimmune serum killing. fH domains necessary for binding sialylated gonococci were determined by incubating organisms with recombinant human fH (rH) and nine mutant rH molecules (deletions spanning the entire fH molecule). rH and all mutant rH molecules that contained SCRs 16-20 bound to the sialylated strain; no mutant molecule bound to serum-sensitive nonsialylated organisms. Sialic acid was demonstrated to be the fH target by flow cytometry that showed a fourfold increase in fH binding that was reversed by neuraminidase-mediated cleavage of sialic acid off gonococci. Functional specificity of fH was confirmed by decreased total C3 binding and almost complete conversion to iC3b on sialylated gonococci. Sialic acid can therefore bind fH uniquely through SCRs 16-20. This blocks complement pathway activation for N. gonorrhoeae at the level of C3.
Antigens, Bacterial↗
Outbreak of nosocomial Acinetobacter baumannii bacteremia in a high risk ward.
Acinetobacter baumannii is emerging as a major cause of nosocomial infections particularly in high risk patients. Being resistant to adverse environmental conditions, it can stay for prolonged periods in the hospital environment. We report an outbreak in the medical oncology ward where nine patients suspected of bacteraemia were blood culture positive for A. baumannii from the two samples each, one collected through the i.v. cannula and another through the peripheral veneous puncture. The bacteria was also isolated from the environmental sources from the various samples collected. The biotype, antibiogram, cellular protein profiles on SDS-PAGE and the restriction enzyme analysis patterns of the patient isolates and the environmental isolates were similar. This points to the environment as a source of infection. With reinforcement of proper barrier nursing and use of disposable heparine ampoules it was possible to control the outbreak.
Acinetobacter Infections↗
Dental and skeletal changes after intraoral molar distalization with sectional jig assembly.
The present study was conducted on 10 subjects to evaluate dental and skeletal changes after intraoral molar distalization. The maxillary molars were distalized with a sectional jig assembly. Sentalloy open coil springs were used to exert 150 gm of force for a period of 12 weeks. A modified Nance appliance was the main source of anchorage. The pre- and postdistalization records included dental study casts, clinical photographs, and cephalograms. A total of 665 readings recorded from lateral cephalograms and dental casts were subjected to statistical analysis. The mean distal movement of the first molar was 2.78 mm, which was highly significant (o < 0.001). It moved distally at the rate of 0.86 mm/month. There was clinically some distal tipping (3.50 degrees) and distopalatal rotation (2.40 degrees). These changes were statistically significant (p < 0.001). The second molars accompanied the first molars and moved distally by nearly the same amount. There was 1.00 mm increase in the overjet and 2.60 degrees mesial tip of second premolar. The changes in the facial skeleton and dentition bases were minimal and statistically not significant. However, there was clockwise rotation of the mandible of 1.30 degrees that was statistically significant. This was the result of molar extrusion (1.60 mm).
Adolescent↗
Forgotten role of adrenaline in the management of anaphylactic reaction.
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Anaphylaxis↗
Defects in auxiliary redox proteins lead to functional methionine synthase deficiency.
Methionine synthase catalyzes a methyl transfer reaction from methyltetrahydrofolate to homocysteine to form methionine and tetrahydrofolate and is dependent on methylcobalamin, a derivative of vitamin B12, for activity. Due to the lability of the intermediate, cob(I)alamin, the activity of methionine synthase is additionally dependent on a redox activation system. In bacteria, two flavoproteins, NADPH-flavodoxin reductase and flavodoxin, shuttle electrons from NADPH to methionine synthase. Their mammalian counterparts are unknown, and a putative intrinsic thiol oxidase activity of the mammalian methionine synthase has been proposed to be involved. We demonstrate that the mammalian methionine synthase can be activated in an NADPH-dependent reaction and requires a minimum of two redox proteins. This model is consistent with our results from biochemical complementation studies between cblG and cblE cell lines and mutation detection analysis in cblG cell lines. These demonstrate that the cblG cell line has defects affecting methionine synthase directly, whereas the cblE cell line has defects in the redox proteins. We have also identified a P1173L mutation in the activation domain of methionine synthase in the cblG cell line WG1505.
5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
Prognosis of acute renal failure in children: a multivariate analysis.
Various factors were analyzed in 80 consecutive children under 16 years who had acute renal failure (ARF), for various prognostic factors. Overall mortality was 42.5%, with significantly higher levels seen in hemolytic uremic syndrome (68%, P < 0.05) and associated with cardiac surgery (90.9%, P < 0.01). Anuria (67.6% vs. 43.5%, P < 0.05), need for dialysis (85.3% vs. 56.5%, P < 0.05), neurological complications (50% vs. 6.3%, P < 0.01), and respiratory complications (35.2% vs. 2.1%, P < 0.01) were significantly higher in nonsurvivors than survivors. Multiple regression analysis showed the presence of neurological and respiratory complications to be poor prognostic factors.
Acute Kidney Injury↗
Tuberculosis in childhood nephrotic syndrome in India.
We studied the prevalence, clinical features, and impact of tuberculosis (TB) on children with nephrotic syndrome (NS). Of the 300 children with NS, 28 (9.3%) were diagnosed as having TB. This occurred following the initiation of immunosuppressive therapy in 27 children, and in 1 child it preceded the onset of NS. Pulmonary involvement was the commonest (22/28), followed by tubercular lymphadenitis (2/28), meningitis (2/28), and occult TB (2/28). Of the various diagnostic criteria, history of previous cough, fever, or exposure to a case of TB (23/28) and chest skiagram (21/28) were the most useful. The occurrence of TB did not induce a relapse or affect the subsequent response to steroid therapy (as is often seen with other infections) or have a deleterious effect on renal function. Patients who received higher doses of steroids (frequent relapsers, steroid dependent, initial non-responders, and subsequent non-responders) had a significantly higher prevalence of TB (19/148) than those who received lower doses (infrequent relapsers 8/151) (P = 0.04). We thus found TB to be an important complication of children with NS in our country. The conventional diagnostic tests, such as Mantoux and acid-fast bacilli isolation, are often unhelpful in these children, and a high index of suspicion is required, especially in children who require frequent courses of steroid therapy.
Adolescent↗
Methionine synthase from pig liver.
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5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
Hereditary palmoplantar keratodermas in South India.
Thirty-one patients with inherited palmoplantar keratodermas (PPKs) were screened from 59,490 cases who visiting the OPD of JIPMER, Pondicherry. The prevalence rate was 5.2 per 10,000 population (1:2000 approx.). PPKs were more common in males (25 patients) than females (6 patients); the overall male to female ratio was 4.2:1. The incidence was highest in the group from 0-10 years of life (67.7% of cases). Unna-Thost syndrome topped the list with 38.7% of cases and its prevalence 1:6000 (approx.), followed by Greither's disease (22.9%) and others-Vohwinkel (3 cases), idiopathic punctate (2 cases), ichthyosis vulgaris associated PPK (2 cases) etc. This study has for the first time reported the prevalence and patterns of hereditary PPKs in South India.
Adolescent↗
Renal artery stenosis in aortoarteritis: spectrum of disease in children and adults.
Nonspecific aortoarteritis is the commonest cause of renovascular hypertension (RVH) accounting for 87% of the patients in the present study. We compared the clinical and radiographic features and outcome in children (n = 16) and adult (n = 24) patients with aortoarteritis. Children have a shorter duration of disease and present more commonly with constitutional symptoms. All the patients were hypertensive; however, malignant hypertension and hypertensive encephalopathy were more common in children. Abdominal bruit and asymmetry of pulses were present only in 75 and 35% of the patients, respectively. Asymmetric kidney size on ultrasound was present in 15 of 24 adults, whereas 9 of 16 children had equal sized kidneys. Captopril renography had a better sensitivity for detection of RVH in children (13 of 16 in children vs. 12 of 24 in adults showing positive results). On intra-arterial digital substraction angiography, abdominal aortic involvement was invariable, whereas the thoracic aorta was involved less frequently in both age groups. Angiographic scores for the severity of vascular involvement was significantly lesser in children (6.87+/-4.8) as compared to adults (11.32+/-4.5). Thirteen of the 15 children were found suitable for revascularization, whereas 12 of 24 adults were not considered for revascularization as their kidneys were small and contributed to less than 10% of total function. Six of the adult patients underwent nephrectomy for the control of blood pressure. Results of angioplasty were also better in children than adults. We conclude that children present earlier with less severe vascular disease and respond better to revascularization, as compared to adults.
Adolescent↗
Chronic renal failure in India.
A prospective study of all new cases of chronic renal failure (CRF) including inservice referrals was done at our hospital over a period of 1 year from May 1994 to April 1995. The diagnosis of CRF was based on clinical, laboratory, and radiological features. Kidney biopsies were done when indicated. The patients were subdivided into various etiologic groups of primary renal disease according to standard criteria. There were a total of 835 cases of CRF with a median age of 43 years (range 10 days to 90 years); 67.8% of them were men. Glomerulonephritis (28.6%), diabetic nephropathy (23.2%), and interstitial nephritis (16.5%) were the most common causes of CRF, followed by obstructive nephropathy (6.4%), benign nephrosclerosis (4.1%), and polycystic kidney disease (2%). However, in patients more than 40 years of age, diabetic nephropathy was the most common cause (36.8%). The cause of CRF was unknown in 16.2% of the cases. One hundred twenty-one patients (14.5%) had an acute deterioration of their underlying renal dysfunction at presentation. This was most commonly due to accelerated hypertension (26.1%), infection (22.4%), volume depletion (20.1%), and drugs (14.9%). Anti-inflammatory drugs were the most common drugs responsible for the acute decline in renal function. One year after their initial presentation, of the 512 patients (61.3%) with end stage renal disease, 12.5% had died, 17% had received a kidney allograft, 12.7% were on some form of maintenance dialysis, and 295 patients were lost to follow-up. Of the 323 patients with less severe illness, 7 died, 209 were on outpatient treatment, and 107 patients were lost to follow-up. We conclude that the pattern of CRF in India does not differ greatly from that in the developed countries. However, it carries a poorer prognosis due to late referral and limited availability and affordability of renal replacement therapy in India.
Adolescent↗
Acute cortical necrosis in falciparum malaria: an unusual cause of end-stage renal disease.
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Adult↗
Platelet calcium pump activity in essential hypertensives and their first-degree relatives.
Intracellular free Ca2+ concentration has been shown to be elevated in platelets of patients with essential hypertension. This study was designed to characterize Ca(2+)-pump activity of the platelet membranes (surface and intracellular) in these patients A double-blind study was carried out. Untreated and treated (on beta-blockers) essential hypertensives were studied in comparison with normotensive control subjects. First degree blood relatives of essential hypertensives were also studied. The Ca2+ activation kinetics of the enzyme showed a significant decrease in the Vmax (for the plasma- and intracellular membranes) and Km (for the intracellular membranes) in the essential hypertensive patients. Increased platelet membrane cholesterol content was observed in these patients. Lowered Ca2(+)-efflux by Ca2(+)-ATPase may lead to elevated intracellular free Ca2(+)-levels in platelet of essential hypertensives. A lowered Ca2(+) -ATPase activity may emerge as a marker for essential hypertension.
Adolescent↗
Acute viral hepatitis types E, A, and B singly and in combination in acute liver failure in children in north India.
The aetiological agents responsible for, and the outcome of, acute liver failure were investigated prospectively in 44 children (29 males, 15 females) attending a tertiary health care facility in India. The children were between the ages of 2 months and 13 years. Studies for viral infections and other etiologies could be carried out in 40 patients. Specific aetiological labels were possible in 35 (87.5%) patients. Thirty (75%) had evidence of acute viral hepatitis. Acute hepatitis E virus (HEV) infection was found in a total of 18 children, with hepatitis A (HAV) in 16, hepatitis B in 5, and C in 1. Seven had isolated infection with hepatitis E, five with A, and four with B. Nine had both E and A infection. Superinfection of HEV was observed in a child with Indian childhood cirrhosis (ICC). Acute HEV infection was confirmed by immunoblot assay in all the patients and in eight of these, HEV-RNA was also detected in the serum. HAV was involved in 37.5% of cases with isolated infection in 10% (4 of 40). The aetiological factors associated with acute liver failure, apart from HAV and HEV, were other hepatotropic viruses (22.5%), Wilson's disease (5%), ICC (5%), and hepatotoxic drugs (7.5%). In five patients, no serological evidence of acute viral hepatitis could be found, neither did the metabolic screen yield any result. It was observed that enterically transmitted hepatitis viruses (HAV and HEV) were associated with 60% of acute hepatic failure in children. Mixed infection of HAV and HEV formed the single largest aetiological subgroup. In developing countries, where hepatitis A and E infections are endemic, severe complications can arise in the case of mixed infection. This may contribute to most of the mortality from acute liver failure during childhood.
Acute Disease↗
Families of smooth confidence bands for the survival function under the general random censorship model.
Randomly right censored data often arise in industrial life testing and clinical trials. Several authors have proposed asymptotic confidence bands for the survival function when data are randomly censored on the right. All of these bands are based on the empirical estimator of the survival function. In this paper, families of asymptotic (1-alpha) 100% level confidence bands are developed from the smoothed estimate of the survival function under the general random censorship model. The new bands are compared to empirical bands, and it is shown that for small sample sizes, the smooth bands have a higher coverage probability than the empirical counterparts.
Clinical Trials as Topic↗