Biomedical subjects

V Bhatnagar

Publications and source records attributed to V Bhatnagar.

At least 37 records · Page 2Linked to original sources

PubMed2001

Ratio of isolated photon cross sections in pp macro collisions at square root of s = 630 and 1800 GeV.

The inclusive cross section for production of isolated photons has been measured in pp macro collisions at square root of s = 630 GeV with the D0 detector at the Fermilab Tevatron Collider. The photons span a transverse energy (E(T)) range from 7-49 GeV and have pseudorapidity absolute value of eta < 2.5. This measurement is combined with the previous D0 result at square root of s = 1800 GeV to form a ratio of the cross sections. Comparison of next-to-leading-order QCD with the measured cross section at 630 GeV and the ratio of cross sections show satisfactory agreement in most of the E(T) range.

Journal Article↗

PubMed2001

Search for new physics using QUAERO: a general interface to D0 event data.

We describe QUAERO, a method that (i) enables the automatic optimization of searches for physics beyond the standard model, and (ii) provides a mechanism for making high energy collider data generally available. We apply QUAERO to searches for standard model WW, ZZ, and t t macro production, to searches for these objects produced through a new heavy resonance, and to the first direct search for W'-->WZ. Through this interface, we make three data sets collected by the D0 experiment at square root of [s] = 1.8 TeV publicly available.

Journal Article↗

PubMed2001

Search for heavy particles decaying into electron-positron pairs in pp collisions.

We present results of searches for technirho (rho(T)), techniomega (omega(T)), and Z' particles, using the decay channels rho(T),omega(T),Z'-->e(+)e(-). The search is based on 124.8 pb(-1) of data collected by the D0 detector at the Fermilab Tevatron during 1992-1996. In the absence of a signal, we set 95% C.L. upper limits on the cross sections for the processes pp-->rho(T),omega(T),Z'-->e(+)e(-) as a function of the mass of the decaying particle. For certain model parameters, we exclude the existence of degenerate rho(T) and omega(T) states with masses below about 200 GeV. We exclude a Z' with mass below 670 GeV, assuming that it has the same couplings to fermions as the Z boson.

Journal Article↗

PubMed2001

Quasi-model-independent search for new high p(T) physics at D0.

We apply a quasi-model-independent strategy ("Sleuth") to search for new high p(T) physics in approximately 100 pb(-1) of pp collisions at square root of (s) = 1.8 TeV collected by the D0 experiment during 1992-1996 at the Fermilab Tevatron. We systematically analyze many exclusive final states and demonstrate sensitivity to a variety of models predicting new phenomena at the electroweak scale. No evidence of new high p(T) physics is observed.

Journal Article↗

PubMed2001

Ratio of jet cross sections at square root of s = 630 GeV and 1800 GeV.

The D0 Collaboration has measured the inclusive jet cross section in barpp collisions at square root of s = 630 GeV. The results for pseudorapidities (eta)<0.5 are combined with our previous results at square root of s = 1800 GeV to form a ratio of cross sections with smaller uncertainties than either individual measurement. Next-to-leading-order QCD predictions show excellent agreement with the measurement at 630 GeV; agreement is also satisfactory for the ratio. Specifically, despite a 10% to 15% difference in the absolute magnitude, the dependence of the ratio on jet transverse momentum is very similar for data and theory.

Journal Article↗

PubMed2001

Ratios of multijet Cross Sections in p p collisions at radical(s) = 1.8 TeV.

We report on a study of the ratio of inclusive three-jet to inclusive two-jet production cross sections as a function of total transverse energy in p&pmacr; collisions at a center-of-mass energy sqrt[s] = 1.8 TeV, using data collected with the D0 detector during the 1992-1993 run of the Fermilab Tevatron Collider. The measurements are used to deduce preferred renormalization scales in perturbative O(alpha(3)(s)) QCD calculations in modeling soft-jet emission.

Journal Article↗

PubMed2001

Inclusive jet production in pp(macro) collisions.

We report a new measurement of the pseudorapidity (eta) and transverse-energy ( E(T)) dependence of the inclusive jet production cross section in pp(macro) collisions at square root of s = 1.8 TeV using 95 pb(-1) of data collected with the D0 detector at the Fermilab Tevatron. The differential cross section d(2)sigma/(dE(T)d eta) is presented up to eta = 3, significantly extending previous measurements. The results are in good overall agreement with next-to-leading order predictions from QCD and indicate a preference for certain parton distribution functions.

Journal Article↗

PubMed2001

Search for large extra dimensions in dielectron and diphoton production.

We report a search for effects of large extra spatial dimensions in pp collisions at a center-of-mass energy of 1.8 TeV with the D0 detector, using events containing a pair of electrons or photons. The data are in good agreement with the expected background and do not exhibit evidence for large extra dimensions. We set the most restrictive lower limits to date, at the 95% C.L. on the effective Planck scale between 1.0 and 1.4 TeV for several formalisms and numbers of extra dimensions.

Journal Article↗

PubMed2001

Silo construction from a sterile adhesive film and polypropylene mesh in the repair of gastroschisis and omphalocele.

A simple technique of constructing a silo for the treatment of gastroschisis (GS) and omphalocele (OMP) is described. A polypropylene mesh covered on both sides with a sterile transparent adhesive film (incise drape) was used; both these items are freely available in the operating room. The resultant silo is sterile, soft, flexible, sturdy, internally smooth, provides a reasonable barrier, and allows enough visibility of the bowel. This silo was used in the treatment of 25 cases of GS and 13 cases of OMP with acceptable results. Survival was better in patients in whom primary closure could be achieved in both OMP and GS. Silo treatment was associated with higher mortality from septic causes.

Gastroschisis↗

PubMed2001

Thoracoabdominal intestinal duplication with absent inferior vena cava.

We report a rare case of thoracoabdominal intestinal duplication with absent inferior vena cava (IVC). The patient was initially explored with a mistaken diagnosis of diaphragmatic hernia on the basis of a chest radiograph and barium meal. However, a subsequent computed tomography scan revealed a mediastinal mass with an air-fluid level, a hugely dilated azygos vein, and an absent IVC. Thoracoabdominal exploration was required to excise the duplication cyst arising from the jejunum. We believe that this is the first report of this association.

Azygos Vein↗

PubMed2001

Functional outcome after pyeloplasty for unilateral symptomatic hydronephrosis.

The functional outcome and factors influencing improvement after pyeloplasty for ureteropelvic junction (UPJ) obstruction are still debated. This retrospective study was aimed at evaluating the factors associated with functional improvement in symptomatic unilateral hydronephrosis (HDN). Patients (n = 68) who underwent successful pyeloplasty for unilateral symptomatic UPJ obstruction without any other associated urological abnormality were included. Preoperative evaluation included a diuretic renogram (DR) to confirm obstruction and assess the split renal function (SRF). A follow-up DR was obtained 3 months and 1, 2, and 5 years postoperatively. An absolute increase in the differential function of the operated kidney by over 5% was considered significant; such kidneys were classified as improved (group A) and the others as unimproved (group B). The difference between the preoperative and 3-month SRF was highly significant (P < 0.001). Significant (P < 0.01) improvement in SRF continued until 1 year after pyeloplasty. Patients who presented with a mass had significantly greater improvement (P < 0.05) than those who presented with other clinical features. In group A, a significantly higher number of patients presented with a mass. It was also evident that patients aged less than 1 year showed significantly greater (P < 0.01) improvement in SRF than older patients. Thus, in unilateral symptomatic HDN with impaired function, patients who present with a mass or those in whom pyeloplasty was performed before 1 year of age showed significantly greater improvement.

Child↗

PubMed2001

Ectopic pancreas associated with a choledochal cyst and extrahepatic biliary atresia.

Two children with incidentally-diagnosed ectopic pancreatic tissue in the jejunum at surgery for extrahepatic biliary atresia (EHBA) and choledochal cyst (CC) are reported. No case has been reported in the literature describing the association of a CC with ectopic pancreas, and only one case of EHBA associated with ectopic pancreas has been reported. We believe that incidentally-detected ectopic pancreatic tissue should be excised, even though the patient is symptom-free, in order to prevent the risk of serious complications due to either the mass effect or the potential for acute pancreatitis, cystic degeneration, or malignant transformation at a later date.

Biliary Atresia↗

PubMed2001

Giant congenital solitary cyst of the liver: report of a case.

Giant solitary nonparasitic cysts of the liver are rarely encountered in children, and establishing a preoperative diagnosis is usually difficult, especially when the cyst occupies the entire abdomen. We report herein the case of an 8-year-old girl found to have a giant congenital solitary cyst of the liver masquerading as an ovarian cyst.

Child↗

PubMed2001

Cystometric evaluation of reconstructed classical bladder exstrophy.

OBJECTIVE: To evaluate the association of urodynamic variables with continence and upper tract status after reconstruction in patients with classical bladder exstrophy. PATIENTS AND METHODS: Thirty-one patients with bladder exstrophy were assessed 1 year after a modified bladder neck reconstruction. The evaluation included a detailed history, radioisotope renography, voiding cysto-urethrography, ultrasonography and artificial slow-filling cystometry. RESULTS: Fifteen of the 31 patients were satisfactorily continent; their maximum cystometric capacity was higher than that of the incontinent patients. The compliance, assessed as the maximum bladder capacity at a detrusor pressure of < 20 cmH2O, was significantly higher in the continent patients. There was a 45% incidence of unstable contractions in the 31 patients. Persistent sphincteric activity was detected on electromyography in 10 patients during voiding. Twenty-one patients could initiate a detrusor contraction during voiding. The residual volume was significant in nine of the 21 patients who attempted to void. Patients with a high end-fill pressure (> 40 cmH2O) had a significantly higher incidence of unobstructive hydronephrosis than had patients who had an end-fill pressure of < 40 cmH2O. CONCLUSIONS: Bladder abnormalities are common after reconstruction of bladder exstrophy, with poor compliance, small capacity and unstable contractions. These factors hinder any increase in capacity and cause persistent incontinence. Hypocompliance and high end-fill pressure can lead to upper tract damage even in continent patients. Detailed urodynamic evaluation is vital to assess the results and to plan subsequent treatment.

Bladder Exstrophy↗

PubMed2001

Pericardial foreign body.

The authors describe the case of an inhaled foreign body unusually located in the pericardium. An initial chest skiagram was misinterpreted leading to a negative bronchoscopy. Correct anatomic localization of the foreign body only was established at surgical exploration, despite preoperative computerized tomography scan of the chest. Recognition of the propensity of sharp foreign bodies to migrate is essential in treating these patients. A tracheobronchial foreign body migrating to the pericardium has not been reported previously in the literature. J Pediatr Surg 36:936-938.

Bronchi↗

PubMed2001

Pediatric extragonadal germ cell tumor of the scalp.

Extragonadal germ cell tumors are relatively rare tumors, accounting for 5% to 10% of all germ cell tumors in adults. In children, approximately two thirds of germ cell tumors are extragonadal. Extragonadal germ cell tumor of the scalp is exceedingly rare. The authors report the case of a 1(1/2)-year-old boy with extragonadal germ cell tumor over the occipital region. Examination of the chest, abdomen, and gonads was normal. Computed tomography scan of the head showed a large, well-defined, lobulated, heterogeneously enhancing soft tissue mass lesion in the occipital region. The underlying bone was normal with no evidence of intracranial extension. Biopsy results of the scalp mass showed features consistent with embroynal carcinoma. Serum alpha-fetoprotein (AFP) level was elevated. The child was started on chemotherapy and received 4 cycles of cisplatin, etoposide, and bleomycin (PEB). There was more than 90% reduction in the size of the mass at the end of the fourth cycle. The residual mass was excised and followed up with 2 cycles of postoperative PEB. Ten months after excision the patient is well, without recurrence, and the AFP level is normal.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2001

Transitional cell carcinoma of the urinary bladder following exposure to cyclophosphamide in childhood.

With the increasing survival of children with malignancies, the long-term effects of chemotherapies are now becoming important and one of these dreadful long-term complications is the development of a second malignancy. Described here is a case of transitional cell carcinoma of the bladder developing 8 years following exposure to cyclophosphamide for the treatment of embryonal rhabdomyosarcoma.

Adolescent↗

PubMed2001

Manometric evaluation of postoperative patients of esophageal atresia and tracheo-esophageal fistula.

Symptoms related to esophageal dysmotility are common following successful repair of esophageal atresia (EA) and tracheo-esophageal fistula (TEF). Esophageal manometry was performed in 27 survivors of EA/TEF at a mean age of 30.5 +/- 30.3 months and in 25 age-matched controls (mean age 36.8 +/- 22.6 months). The patients were also evaluated clinically to grade them into 3 result-oriented groups "Excellent", "Good" and "Fair", depending on pre-existing criteria evaluating the ability and ease of swallowing. Gastroesophageal reflux (GER) was evaluated with the help of a radionuclide scan. The mean esophageal and peak esophageal pressures and therefore also the lower esophageal sphincter (LES) pressure were lower in the patients (12.4 +/- 5.5, 34.9 +/- 20.4 and 12.2 +/- 6.8 mm Hg, respectively) compared to the controls (21.1 +/- 6.9, 62.3 +/- 19.3 and 16.8 +/- 4.3 mm Hg, respectively). The mean body pressures were highest with "Excellent" results and lowest with "Fair" results and the LES pressures followed a similar trend. Likewise, in the patients with GER, LES pressure was 12.0 +/- 7.1, 12.3 +/- 3.7, 11.0 +/- 5.7 and 6.9 +/- 5.6 mm Hg with nil, mild, moderate and severe GER, respectively. The pressure and contractility profile of the esophagus was abnormal in the majority of patients, even in the absence of symptoms.

Case-Control Studies↗