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Biomedical subjects

V Bhatnagar

Publications and source records attributed to V Bhatnagar.

At least 19 recordsLinked to original sources
PubMed2003

Search for large extra dimensions in the monojet+E(T) channel with the DØ detector.

We present a search for large extra dimensions (ED) in pp collisions at a center-of-mass energy of 1.8 TeV using data collected by the DØ detector at the Fermilab Tevatron in 1994-1996. Data corresponding to 78.8+/-3.9 pb(-1) are examined for events with large missing transverse energy, one high-p(T) jet, and no isolated muons. There is no excess observed beyond expectation from the standard model, and we place lower limits on the fundamental Planck scale of 1.0 and 0.6 TeV for 2 and 7 ED, respectively.

Journal Article↗
PubMed2003

Evaluation of cerebral vascular reserve by single photon emission tomography in children with congenital hydrocephalus.

BACKGROUND/AIMS: Single photon emission tomography scan (SPECT) is used to measure cerebral blood flow (CBF) and also cerebral vascular reserve (CVR) after intravenous acetazolamide (ACZ) challenge. This prospective study was designed to test the utility of CVR in congenital hydrocephalus (CHC). METHODS: Patients (n = 21, mean age 6.2 m) with CHC underwent a baseline ultrasonography (US), retinal fundus examination (RF), neurological score (NS), and SPECT to evaluate CVR after intravenous ACZ. Monthly US, RF, NS, CBF, and CVR were evaluated. RESULTS: Ten patients showed good CVR and also had stable NS and RF despite mild to moderate ventriculomegaly and were followed up on conservative treatment. None of these patients in a mean follow-up period of 9.8 months showed deterioration. Eleven patients, who had poor CVR initially, were also treated conservatively. Over a period of 4 months, 8 patients showed a fall in CVR to < 30 % of baseline and a fall in NS despite RF and US remaining the same and hence were operated. Five of these operated cases showed an improvement in CVR and NS over a mean follow-up period of 4 months and the remaining 3 patients failed to show improvement in CVR and NS. CONCLUSIONS: In CHC, CVR measured by ACZ challenge test is a sensitive parameter as alterations in CVR occur prior to changes in other conventional parameters such as ventriculomegaly and RF. Patients with normal CVR at presentation are unlikely to deteriorate and can safely be managed conservatively. Patients who show a deterioration in CVR should be considered for prompt surgery.

Brain↗
PubMed2002

Search for the production of single sleptons through R-parity violation in pp; collisions at square root (s) =1.8 TeV.

We report the first search for supersymmetric particles via s-channel production and decay of smuons or muon sneutrinos at hadronic colliders. The data for the two-muon and two-jets final states were collected by the D0 experiment and correspond to an integrated luminosity of 94+/-5 pb(-1). Assuming that R parity is violated via the single coupling lambda'211, the number of candidate events is in agreement with expectation from the standard model. Exclusion contours are given in the (m(0),m(1/2)) and (m(x),m(v)) planes for lambda(')(211)=0.09, 0.08, and 0.07.

Journal Article↗
PubMed2002

Search for R-parity violating supersymmetry in two-muon and four-jet topologies.

We present results of a search for R-parity-violating decay of the neutralino chi;01, taken as the lightest supersymmetric particle, to a muon and two jets. The decay proceeds through a lepton-number violating coupling lambda(')(2jk) (j=1,2; k=1,2,3), with R-parity conservation in all other production and decay processes. In the absence of candidate events from 77.5+/-3.9 pb(-1) of data collected by the D0 experiment at the Fermilab Tevatron in pp collisions at sqrt[s]=1.8 TeV, and with an expected background of 0.18+/-0.03+/-0.02 events, we set limits on squark and gluino masses within the framework of the minimal low-energy supergravity-supersymmetry model.

Journal Article↗
PubMed2002

Initial surgical treatment as a determinant of bladder dysfunction in posterior urethral valves.

Bladder function in patients with posterior urethral valves (PUV) has an immense impact on long-term continence and renal function. Bladder dysfunction was corelated with the initial surgical treatment in 67 patients with PUV treated between 1985 and 2000. Age at presentation, current age, duration of follow-up, initial surgical treatment (diversion or valve fulguration), trends of renal function tests, voiding disturbances, and changes in the upper tracts were recorded. Urodynamic studies were done in all patients to determine urine flow rates, residual volume, maximal cystometric capacity (MCC), bladder compliance, involuntary detrusor activity, and pressure-specific bladder volume (PSBV) at 30 cm water. The patients were divided into three groups depending on the initial treatment: fulguration (n = 38), vesicostomy (n = 25), and ureterostomy (n = 4). At the time of this study voiding symptoms persisted in 45 patients. Mean percent MCC (% MCC) was 62%, 96%, and 100% of normal in the vesicostomy, fulguration, and ureterostomy groups, respectively (P = 0.002). Large-capacity bladders were seen in 10.9% of patients, mostly in pubertal and post-pubertal boys who were treated initially by either fulguration or ureterostomy; vesicostomy adversely affected bladder capacity and compliance (P = 0.007). PSBV was decreased in 48% of patients in the vesicostomy group and was significantly lower in the other groups (P = 0.01). Mean percent PSBV was 75%, 95%, and 96% of normal in the vesicostomy, fulguration, and ureterostomy groups, respectively. Uninhibited contractions were present in 21 patients (14 in the vesicostomy group) (P = 0.01). The highest incidence of upper-tract deterioration was seen with %MCC below 60% of normal (P = 0.001). The predominant urodynamic patterns were: (1) fulgurated group: good-capacity, compliant bladder; (2) vesicostomy group: small-capacity, hyperreflexic bladder; and (3) ureterostomy group: good capacity, compliant bladder. Primary valve ablation is associated with better bladder function than vesicostomy and should be the treatment of choice in PUV. Also, vesicostomy and ureterostomy have distinctly different effects on bladder function.

Child↗
PubMed2002

Urinary-tract infection affects somatic growth in unilateral symptomatic hydronephrosis.

To assess whether symptomatic unilateral ureteropelvic junction obstruction (SUUPJO) affects somatic growth and, if so, the parameters associated with it, 61 children (54 boys and 7 girls) who underwent pyeloplasty for SUUPJO without any other associated urological abnormalities were retrospectively studied. Height was compared with standard growth charts and was considered to be affected if it was below 2.00 Z-score. Such children were considered group B and the rest group A. Mean (+/-SD) age at presentation and mean (+/-SD) split renal function (SRF) (%) of the affected kidney were 6.0 +/- 4.0 years and 27.3 +/- 13.2, respectively, for the entire group. Somatic growth was affected in 16 (12 boys, 4 girls) children (26.2%). Urinary tract infection (UTI) was the presenting symptom in 11 (69%) and 5 (11%) children in groups B and A, respectively. Impaired somatic growth had no association with age at presentation or SRF, but a significant association (P < 0.001) was found with UTI. The mean post-surgery height percentile (2.92 +/- 4.85) over a mean follow-up of 3.37 +/- 1.86 years was significantly (P < 0.005) better compared with pre-surgery height percentile (0.67 +/- 0.96) in group B, indicating catch-up growth after surgery. In SUUPJO, somatic growth is affected. Presentation with UTI has a significant association, and height significantly improves after surgery in these patients.

Body Height↗
PubMed2002

A clinicopathological study of acute necrotising jejunoileitis.

We describe a variety of acute necrotizing enteritis that is endemic to the Indian subcontinent. During the period 1992-1998, 18 cases of acute jejunoileitis (AJI) were managed. Only those in whom the diagnosis was confirmed at laparotomy have been included in this study. The most common symptoms were abdominal pain (100%), fever (77%), and blood in the stool (100%). A stricture following conservative treatment was present in 1 case. The mean age at presentation was 6.5 years (range 6 months-12 years); the male:female ratio was 1.2:1. All cases were seen during May-October. Routine investigations and X-ray films were nonspecific. Stool cultures did not show any clostridia, shigella, or salmonella. The jejunum was involved most commonly; 28% of patients did not require a bowel resection. Only 1 child presented with shock; the mortality was less than 5%. Short-bowel syndrome resulted in 1 patient due to extensive disease. The histopathologic features that were characteristic of the disease were patchy transmural mucosal necrosis extending centrifugally with submucosal edema, interstitial hemorrhage, type III hypersensitivity reaction, and extensive neovascularization. This type of AJI seen in South/Southeast Asia does not seem to be due a to bacterial infective etiology; immune mediation is suggested. The milder forms can be confused with dysentery. Mild forms of the disease can be managed conservatively, but carry the risk of developing strictures. This disease should be suspected in cases of prolonged dysentery during the summer and autumn months.

Acute Disease↗
PubMed2002

Search for leptoquark pairs decaying into nunu+jets in pp collisions at square root[s] = 1.8 TeV.

We present the results of a search for leptoquark (LQ) pairs in (85.2+/-3.7) pb(-1) of pp* collider data collected by the D0 experiment at the Fermilab Tevatron. We observe no evidence for leptoquark production and set a limit on sigma(pp*-->LQLQ-->nunu+jets) as a function of the mass of the leptoquark (m(LQ)). Assuming the decay LQ-->nuq, we exclude scalar leptoquarks for m(LQ) < 98 GeV/c(2), and vector leptoquarks for m(LQ) < 200 GeV/c(2) and coupling which produces the minimum cross section, at a 95% confidence level.

Journal Article↗
PubMed2002

Search for the scalar top quark in pp collisions at square root[s] = 1.8 TeV.

We have performed a search for scalar top quark (stop) pair production in the inclusive electron-muon-missing transverse energy final state, using a sample of pp events corresponding to 108.3 pb(-1) of data collected with the D0 detector at Fermilab. The search is done in the framework of the minimal supersymmetric standard model assuming that the sneutrino is the lightest supersymmetric particle. For the dominant decays of the lightest stop, t-->b chi+1 and t-->blnu, no evidence for signal is found. We derive cross-section limits as a function of stop ( t ), chargino ( chi+1), and sneutrino ( nu) masses.

Journal Article↗
PubMed2002

Direct search for charged higgs bosons in decays of top quarks.

We present a search for charged Higgs bosons in decays of pair-produced top quarks in pp collisions at sqrt[s] = 1.8 TeV recorded by the D0 detector at the Fermilab Tevatron collider. With no evidence for signal, we exclude most regions of the ( M(H+/-),tan(beta)) parameter space where the decay t--> H(+)b has a branching fraction >0.36 and B(H+/--->tau(nu)(tau)) is large.

Journal Article↗
PubMed2002

Semen analysis in post-pubertal patients with posterior urethral valves: a pilot study.

The issues of sexual function and fertility are becoming relevant in patients with posterior urethral valves (PUV), as more of them reach adulthood. To evaluate the semen of post-pubertal patients with PUV as a determinant of future fertility, all such patients (age >16 years) attending the follow-up urology clinic of our department from 1985 to December 1999 were contacted. Of the nine patients contacted, eight agreed to form the study group. All eight patients were asked to provide a post-masturbation semen sample and urine. Semen was analysed for pH, viscosity, liquefaction time, sperm morphology, sperm count, motility, and agglutination. The patients ages ranged from 16 to 21 years (mean 17.5 years). One patient with chronic renal failure awaiting a renal transplant refused to give a semen sample; two tried but failed to ejaculate on three consecutive visits. Their urine was negative for sperm. Of the five patients who gave semen, the liquefaction time was high in two. pH ranged from 7.2 to 8, sperm counts were 24-80 million. None of the patients had oligospermia. Abnormal sperm agglutination was present in four cases; a higher percentage of immotile sperm was also present in four. Semen abnormalities in the form of increased liquefaction time, abnormal sperm agglutination, and a high percentage of immotile sperm were thus seen in the present study. The bearing of these findings on subsequent sexual function and fertility remains a matter of speculation.

Adolescent↗
PubMed2002

The role of DMSA scans in evaluation of the correlation between urinary tract infection, vesicoureteric reflux, and renal scarring.

The correlation between urinary tract infection (UTI), vesicoureteric reflux (VUR) and renal scarring was studied in 89 patients (177 renal units; 1 solitary kidney) during the period 1997-2000. There were 63 males and 26 females; ages ranged from neonates to 14 years. UTI was diagnosed on the basis of a positive urine culture, VUR was diagnosed and graded by micturating cystourethrogram (MCU), and renal scarring was assessed by technetium 99 m Tc-dimercaptosuccinic acid (DMSA) scan. Ultrasonography (US) was done to evaluate renal tract dilatation and other structural abnormalities. A follow up DMSA scan was performed approximately 6 months after the initial scan. VUR was present in 106 of the 171 renal units in which it was studied and absent in 65 units. The majority of the VUR was grade V. Renal scars were seen in 90 of 177 renal units at presentation and in 72 of the 163 renal units studied at follow-up. Some information was lacking in 31 patients; hence, the correlation between UTI, VUR, and renal scarring was done in 58 patients. The majority of the suspected scars at presentation were not seen at follow-up, but most of the established scars persisted. Only 2 renal units showed scars for the first time on follow-up. On US, approximately 50% of normal kidneys showed either suspicious or established scars on DMSA scan, and patients with bilateral abnormality on US showed renal scars. Renal scars were seen in 15 of 23 children without VUR, 17 of 18 with unilateral VUR, and 16 of 17 with bilateral VUR. Thus, there is a cause-and-effect relationship between UTI and renal scarring that is made worse by VUR. DMSA scans have been shown to be the most reliable method of assessing renal scarring, and an abnormal US scan showing upper-tract dilatation or a structural abnormality may have a predictive value in the detection of renal scarring.

Adolescent↗
PubMed2002

Augmentation colocystoplasty in bladder exstrophy.

A good bladder capacity and adequate outlet resistance determine success after staged reconstruction of bladder exstrophy (BE). Augmentation cystoplasty (AC) is an established salvage procedure to treat the small, noncompliant bladders of some of these children. In a series of 89 patients with BE treated over the last 12 years, 19 underwent detubularized augmentation colocystoplasty (ACC) as an adjunctive procedure. Nine underwent ACC at the time of bladder-neck reconstruction (BNR) for small bladder capacity and poor compliance; 10 underwent ACC as a secondary procedure after BNR for persistent urinary incontinence or poor bladder compliance and upper-tract deterioration. The follow-up period ranged between 6 months and 12 years (mean 41 months). Complications included symptomatic urinary-tract infection in 4 patients, recurrent epididymo-orchitis in 2, calculi in 3, colonic anastomotic dehiscence in 1, bladder-patch fistula in 2, and secondary coloureteric-junction obstruction in 1. There was no postoperative reservoir perforation or mortality. The upper tract remained normal or stable in all patients. Nine of the 19 patients are dry both day and night; 4 others are dry during the day but have occasional nocturnal wetting. Three patients have nocturnal wetting with stress incontinence and 2 remain incontinent. Seven patients can void effectively using abdominal contractions and 12 require clean intermittent catherization to ensure complete voiding. The indications and results of AC in BE from other series are reviewed. AC is an important and safe adjunctive procedure in a subset of BE patients with small and poorly compliant bladders. Despite the known complications, more liberal use of AC in BE is warranted.

Adolescent↗
PubMed2002

The role of imipramine therapy in bladder exstrophy after bladder neck reconstruction.

OBJECTIVE: To assess the role of imipramine therapy after bladder neck reconstruction in patients with bladder exstrophy. PATIENTS AND METHODS: Seventeen children with bladder exstrophy who achieved partial continence after bladder neck reconstruction received imipramine (1.5-2 mg/kg body weight) for a mean duration of 9.5 months. Assessment before and after therapy included an objective classification of the continence status and artificial slow-fill cystometry. RESULTS: Eleven of the 17 patients had a good clinical response to imipramine, with an increase in the continent period to > 2 h, and in nocturnal continence. The urodynamic findings showed a significant improvement in the capacity, end-fill pressure, uninhibited contractions and '20 below' capacity. Only minor side-effects of the drug were reported. CONCLUSION: Imipramine has a role in patients who achieve partial continence after reconstruction, and who have a moderately small capacity bladder with poor compliance and uninhibited contractions.

Antidepressive Agents, Tricyclic↗
PubMed2002

Hormonal analysis in post-pubertal patients with posterior urethral valves.

AIMS: Infertility in patients with posterior urethral valves (PUV) is known but the exact incidence and etiology is still speculative; it may be partly due to dysfunction of genital organs. The aim of this study is to analyse the hormonal profile of post-pubertal patients with PUV. MATERIALS AND METHODS: All post-pubertal patients with posterior urethral valves (age > 16 years) visiting the follow-up urology clinic of our department from 1985 to December 1999 were contacted and requested to participate in the study; 9 patients agreed and form the study group. The medical records were reviewed. Physical examination included examination of the genitalia and secondary sexual characteristics. Blood samples were taken for estimation of lutenizing hormone (LH), follicle-stimulating hormone (FSH), prolactin and testosterone. RESULTS: Ages ranged from 16 - 21 years (mean age = 17.5 years). Physical examination was normal for the entire study group except for 2 patients; one patient had hypertension and the other had unilateral undescended testis at the time of initial presentation. Secondary sexual characteristics were normal in all patients. At the time of the study, one patient had chronic renal failure; in the others the renal function tests were normal. LH and testosterone were normal in all patients including the patient with unilateral undescended testis, and one patient had marginally elevated FSH. Hyperprolactinemia was noted in 5 of 9 patients. CONCLUSION: In the present study, hyperprolactinemia was seen in 62 % (5 of 9) patients. Hyperprolactinemia is known to cause slow ejaculation and can have an impact on the subsequent fertility status of these patients. The bearing of these findings on subsequent sexual and fertility functions of PUV patients requires further investigation.

Adolescent↗
PubMed2002

Angiographic and immunologic studies in acute necrotizing jejunoileitis.

Eighteen cases of laparotomy-proven acute necrotizing jejunoileitis were treated during the period 1992-1998. Routine laboratory investigations and bacteriological studies were non-contributory towards establishing an etiological basis for the diagnosis. Superior mesenteric artery digital subtraction angiography, carried out in five patients, demonstrated extensive neovascularization. IgG, IgM and IgA were normal in all eight children in whom it was measured; IgE levels were grossly elevated (mean 900 IU/ml; normal range 0-100 IU/ml). Four cases had evidence of hypersensitivity reactions (type I in one patient and type III in three patients) on histopathological examination of the resected small bowel. In addition, histopathological examination also showed the neovascularization observed on angiography. The evidence suggests an immunologically mediated insult resulting in intense vasculitis, which in turn causes ischemic damage to the bowel wall.

Biopsy↗
PubMed2002

Urinary citrate excretion in idiopathic nephrolithiasis.

OBJECTIVE: To determine urinary citrate excretion in children with nephrolithiasis and normal controls. DESIGN: Prospective. SETTING: Tertiary care center in New Delhi. METHODS: This study was done on 50 children, below the age of 12 years, with idiopathic urinary calculi and 150 age and weight matched controls. The children were divided into 3 groups: Group 1 (1-4 years), Group 2 (5-8 years) and Group 3 (9-12 years). Urinary citrate was estimated in a 24-hour urine sample using colorimetric method. The stones removed from these children were also analysed. RESULTS: There was a preponderance of urinary stones in males; the highest incidence being in Group 1. Excretion of citrate in 24-hour urine sample was significantly lower in patients compared to controls, for males in all age groups and for females in Group 3. However, there was no statistically significant difference in the urinary citrate value between males and females in a given age group for either controls or patients. The urinary citrate excretion increased with age in patients and controls, but the levels in patients were lower. Depending upon the constituents, four types of stones were identified, calcium phosphate, calcium oxalate, uric acid and magnesium ammonium phosphate. Nine stones had at least more than one major constituent. Hypocitraturia was detected in 43 percent cases. The incidence was 76 percent for calcium phosphate, 87 percent for calcium oxalate, 40 percent for uric acid stones and 50 percent for magnesium ammonium phosphate. CONCLUSION: This study shows that low urinary citrate is associated with urinary stones in children, especially in endemic areas, in the absence of obvious etiological factors. Urinary citrate excretion should be determined in all children with nephrolithiasis.

Case-Control Studies↗