Biomedical subjects

S K Gupta

Publications and source records attributed to S K Gupta.

At least 307 records · Page 17Linked to original sources

PubMed1997

Recombinant human monoclonal antibody IgG1b12 neutralizes diverse human immunodeficiency virus type 1 primary isolates.

The CD4-binding domain of human immunodeficiency virus type 1 (HIV-1) gp120 elicits antibodies that are present in infected human sera. Monoclonal antibodies that recognize the HIV-1 gp120 CD4-binding domain have been isolated. Some of these antibodies can neutralize laboratory-adapted strains of HIV-1 and probably mediate neutralization by interfering with virus binding to its cellular CD4 receptor. However, most anti-CD4 binding domain antibodies do not neutralize primary HIV-1 isolates. We used primary HIV-1 isolates in an infectivity reduction assay to test the uniquely derived anti-CD4 binding domain recombinant human monoclonal antibody, IgG1b12. All of the tested HIV-1 isolates were neutralized by this antibody. Additional studies indicated that neutralization of a primary isolate with MAb IgG1b12 did not require continuous exposure of human peripheral blood mononuclear cell cultures to the antibody. Finally, a complete IgG1 molecule of an in vitro-selected b12 FAb mutant with a > 400-fold increase in affinity was assembled, expressed in mammalian cells, and evaluated in the infectivity reduction assay in comparative studies with the parent IgG1b12 antibody. The mutant did not retain the level of primary isolate neutralization potency that was a property of the parent molecule. Thus, we confirm that recombinant IgG1b12 has a unique specificity, and that it can neutralize all primary isolates tested in human PBMC cultures in vitro.

Antibodies, Monoclonal↗

PubMed1997

Human immunodeficiency virus type-1 p24 sequence from an Indian strain: expression in Escherichia coli and implications in diagnostics.

A 637-bp fragment, corresponding to the p24 human immunodeficiency virus (HIV) core protein from the gag ORF, was PCR amplified from DNA isolated from peripheral blood mononuclear lymphocytes (PBML) of an asymptomatic HIV-1 seropositive human subject from Bombay and cloned into PCRScript SK(+). The nucleotide sequence revealed highest homology (98.6%) with the consensus sequence of the HIV-1 B subtype. The 637-bp KpnI-HindIII fragment was cloned downstream from a His6 tag in the pQE30 vector under the control of phage T5 promoter leading to production of a 6XHis-p24 fusion protein in Escherichia coli. It showed an approx. 24-kDa band by SDS-PAGE. The recombinant p24 reacted with serum samples from HIV-infected subjects when tested by Western blot and ELISA.

Amino Acid Sequence↗

PubMed1997

Expression of bonnet monkey (Macaca radiata) zona pellucida-3 (ZP3) in a prokaryotic system and its immunogenicity.

An internal fragment (978 bp) corresponding to the bonnet monkey (Macaca radiata) ZP3, excluding the N-terminus signal sequence and the C-terminus transmembrane-like domain, was amplified by PCR from a full-length cDNA clone. The amplified Bam HI and SacI restricted fragment was cloned in frame downstream of the T5 promoter under lac operator control for expression in the pQE-30 vector. Recombinant ZP3 (r-ZP3) was expressed as a poly-histidine fusion protein in E. coli strains SG13009[pREP4] and BL-21(DE3). Immunoblot with a murine monoclonal antibody, MA-451 (raised against porcine ZP3 beta-a homologue of bonnet ZP3, and cross-reactive with bonnet zona pellucida) revealed a predominant band of 50 kDa besides degraded fragments. Optimum expression of r-ZP3 was observed at 0.5 mM IPTG. Antisera generated in monkeys against synthetic peptides from the N-(23-45 aa residues) and C-(300-322 and 324-347 aa residues) termini of the deduced bonnet monkey precursor ZP3 sequence reacted with the r-ZP3 protein in ELISA. The r-ZP3 expressed in SG13009[pREP4] was purified on Ni-NTA resin under denaturing conditions and conjugated with diphtheria toxoid (DT). Immunization of a female rabbit and six female bonnet monkeys with the r-ZP3-DT conjugate generated antibodies reactive with r-ZP3 in ELISA. Rabbit r-ZP3 antiserum reacted with porcine ZP3 beta and bonnet r-ZP3 but failed to react with porcine ZP3 alpha in a Western blot. Moreover, antisera when tested by indirect immunofluorescence on bonnet monkey ovarian sections, showed positive fluorescence with zona pellucida. The availability of r-ZP3 will further help in evaluating its efficacy for fertility regulation and understanding the autoimmune oophoritis associated with ZP3 immunization in nonhuman primates.

Amino Acid Sequence↗

PubMed1997

DeMonS--a new deconvolution method for estimating drug absorbed at different time intervals and/or drug disposition model parameters using a monotonic cubic spline.

DeMonS-a new numerical deconvolution method for estimating the amount of drug absorbed at different time intervals and/or drug disposition model parameters-is presented here. In DeMonS, the amount of drug absorbed at different time intervals and/or drug disposition model parameters are the unknown parameters to be calculated. The Fritsch-Butland non-decreasing cubic spline was constructed from the cumulative amount of drug absorbed-time data directly derived from the calculated amount of drug absorbed at different time intervals. The drug absorption rate, which is the derivative of this non-decreasing cubic spline, is therefore represented by a piecewise non-negative quadratic function. The drug concentrations were obtained by convoluting the drug absorption rate quadratic function with the drug disposition model function. The nonlinear optimization method with simple parameter bounds was used to estimate the optimal set of unknown parameters by minimizing the sum of squares of residuals between the observed and predicted drug concentrations. DeMonS has been applied to (i) the griseofulvin data for estimating drug absorbed at different time intervals when the drug disposition model parameters were determined separately from intravenous data, (ii) veralipride double-peak phenomenon data to estimate simultaneously the percentage of cumulative veralipride absorbed and the veralipride disposition model parameters without reference intravenous data, (iii) a comparative bioequivalence study of gastrointestinal therapeutic system (GITS) pseudoephedrine HCI (PeHCI) controlled-release oral dosage forms when the drug disposition model parameters were not available, and (iv) estimation of both drug disposition model parameters and the absorption rate of drug from Testoderm (testosterone transdermal system) in the presence of endogenous testosterone production. DeMonS was implemented using MATLAB and NAG MATLAB Toolbox, and is available for Windows 3.1.

Absorption↗

PubMed1997

Transdermal testosterone administration in hypogonadal men: comparison of pharmacokinetics at different sites of application and at the first and fifth days of application.

In this study of 13 hypogonadal men (25-69 years of age), three open-label, randomized treatments were administered to determine the pharmacokinetics of serum testosterone after application of an investigational testosterone transdermal system to the upper buttocks, upper arm, and back. Testosterone in vivo input kinetics profiles were estimated by DeMonS, a recently developed numerical deconvolution method for estimating drug absorption at different time intervals and/or drug disposition model parameters, and compared on the first and fifth days of system application. Area under the concentration-time curve from 0 to 27 hours (AUC0-27) values for testosterone after one-day applications to the upper buttocks, upper arm, and back were 9,560 ng.hr/dL, 8,651 ng.hr/dL, and 8,988 ng.hr/dL, respectively. Maximum observed concentration (Cmax) values were 482 ng/dL, 462 ng/dL, and 499 ng/dL, respectively. Serum testosterone concentrations were equivalent to each other, and Cmax values fell within the normal range. No drug accumulation was seen with repeated dosing over 5 days.

Administration, Cutaneous↗

PubMed1997

Testosterone pharmacokinetics after application of an investigational transdermal system in hypogonadal men.

This open-label, randomized, placebo lead-in, three-treatment crossover study in 19 hypogonadal men (27-82 years of age) evaluated dose proportionality of serum testosterone concentrations with application of one or two investigational transdermal testosterone systems for application to the arm or torso. Testosterone in vivo kinetics profiles were determined using DeMonS, a recently developed numerical deconvolution method that estimates drug absorption at different time intervals and/or drug disposition model parameters. After application of the investigational transdermal systems, the mean serum testosterone, dihydrotestosterone, estradiol, and free testosterone concentrations were elevated to normal levels. Treatment allowed approximation of the normal circadian pattern of endogenous testosterone secretion, and the increase in serum testosterone concentrations was proportional to the surface area of systems applied. The investigational transdermal system provided effective testosterone replacement therapy as judged by pharmacokinetic parameters.

Administration, Cutaneous↗

PubMed1997

E-cadherin (E-cad) expression in duct carcinoma in situ (DCIS) of the breast.

E-cadherin (E-cad) is an epithelial cell-cell adhesion molecule whose loss or reduced expression is associated with a more invasive tumour phenotype. Ninety-six cases of screen detected pure ductal carcinoma in situ (DCIS) were analysed immunocytochemically for expression of E-cad using the HECD-1 mouse monoclonal antibody. The in situ component in each case was classified on the basis of cytonuclear grade, extent of necrosis, Van Nuys classification and a newly devised Cardiff classification. The amount of E-cad expression was assessed semi-quantitatively using an intensity distribution method. There is significantly more expression of E-cad in well-differentiated DCIS when compared with poorly differentiated DCIS and this finding is highly significant (P < 0.001) irrespective of the classification system used. These findings suggest that progressive loss of E-cad expression may occur at an early stage of breast cancer development.

Breast Neoplasms↗

PubMed1997

Growing skull fractures: a clinical study of 41 patients.

Growing skull fractures are rare complications of head injury, occurring almost exclusively in infants and children under the age of three. A retrospective review at our Institute yielded 41 patients with this entity over a period of 20 years (1975-1995). The age at presentation ranged from less than 1 year to 62 years, with 33 (80.5%) patients being less than 5 years of age. The cause of injury was either a fall from a height (93%) or a road traffic accident. The most common location of a growing skull fracture was either parietal or frontoparietal (56%). One patient had a posterior fossa growing skull fracture. CT scan was performed in 19 patients which demonstrated an underlying porencephalic cyst, hydrocephalus or a cyst communicating with the ventricle. In 5 children, a ventriculo-peritoneal shunt alone was performed. Twenty four patients underwent a duro- and cranioplasty while a duroplasty alone was performed in 8 patients. The material used for cranioplasty included acrylic, wire mesh, steel plates or autologous bone. Three patients died, one due to an anaesthetic complication and two as a result of postoperative meningitis. Post-operative CSF leaks occurred in 3 patients, which were managed by a lumbar drain. Six patients had local wound infection.

Adolescent↗

PubMed1997

Strategies to increase the use of autogenous arteriovenous fistula in end-stage renal disease.

The purpose of this retrospective study was to review our experience with a consecutive group of end-stage renal disease (ESRD) patients using simple strategies to increase the use of autogenous vascular access, and determine whether the current trend of using synthetic bridge-graft fistula (BGF) rather than autogenous arteriovenous fistula (AVF), could be reversed, despite an aging population and broadening criteria for hemodialysis. All patients for vascular access surgery had careful preoperative clinical examination of the arm veins with outflow occlusion to determine the venous anatomy and continuity. Where no veins were apparent or their continuity in doubt, selective preoperative venography was performed. Where veins were unsatisfactory for forearm AVF, new or modified surgical procedures to use both the basilic and cephalic veins in the upper arm were performed. Intraoperative angioscopy was used to monitor vein quality and surgical technique. Ninety-eight primary vascular access procedures were performed in 76 patients, 75 (76.5%) AVF (forearm, n = 41; upper arm, n = 34) and 23 (23.5%) BGF. Forty-one of 76 (54%) had already had at least one previous access procedure prior to this study. More than one access procedure was needed in 16 patients. Preoperative venography was performed in 22 (22.4%) and intraoperative angioscopy in 45 (45.9%) of the 98 procedures. The number of revisions required to maintain patency was significantly higher for BGF (37 revisions in 14/23) than AVF (16 revisions in 13/75) (p < 0.0001, Poisson test) with an annualized secondary revision rate of 1.168 for BGF and 0.173 for AVF (p < 0.0001, Poisson test). AVF had both longer primary (p = 0.0001, log rank test) and secondary patency (p = 0.038, log rank test) than BGF. AVF as the primary vascular access can be significantly increased and the current trend of using BGF reversed with the use of simple clinical strategies to evaluate the suitability of the arm veins for vascular access.

Arm↗

PubMed1997

Vertical lines in distal esophageal mucosa (VLEM): a true endoscopic manifestation of esophagitis in children?

BACKGROUND: We observed an endoscopic abnormally in a group of children with histological esophagitis. We termed this finding "vertical lines in esophageal mucosa" (VLEM). We examined the relationship between the presence of VLEM and significant histologic changes in esophageal mucosal biopsies. METHODS: Between January 1, 1992, and August 31, 1994, the senior author (JFF) performed 255 esophageal biopsies. The procedure reports, available endoscopic photographs, and histology reports were reviewed to establish the endoscopic and histologic appearance of the esophageal mucosa. Intraepithelial cells were counted in a blind review of 42 randomly selected biopsies. RESULTS: The esophageal mucosa had a normal appearance on 160 endoscopic studies (Group 1) and VLEM were the only mucosal abnormalities in 41 endoscopies (Group 2). Histology was normal in 92 of 160 biopsies (57.5%) from Group 1, and 1 of 41 biopsies (2.4%) from Group 2. Most patients in Group 2 had eosinophilic esophagitis (34 of 41, 83%, specificity 0.85, sensitivity 0.5, p > 0.001) which was of moderate to severe intensity (31 of 34, 91.2%, specificity 0.88, sensitivity 0.73, p < 0.001). CONCLUSIONS: Histology usually demonstrated moderate to severe inflammation when VLEM were present. VLEM may be a highly specific endoscopic feature of esophagitis in children.

Adolescent↗

PubMed1997

Traumatic spinal subarachnoid hematoma: report of a case with MRI.

BACKGROUND: Spinal subarachnoid hematoma (SAH) is uncommon following traumatic injury to the spine. There are few case reports of neurologic deficit secondary to traumatic spinal SAH. CASE DESCRIPTION: This 6-year-old boy was injured in a vehicular accident from which he became paraplegic and presented to us 1 week later. Plain X rays were normal and a myelo-computed tomography (CT) scan demonstrated an irregular intradural lesion from D10-L2. The magnetic resonance imaging (MRI) revealed an SAH at D11-12 level, posterior to the cord, which was surgically evacuated. The patient did not improve neurologically. CONCLUSION: Significant cord injury and neurologic deficit can occur without obvious abnormalities on plain X rays or CT scan. MRI is very useful in detecting these lesions and can help in their management.

Child↗

PubMed1997

Brain abscess in renal transplant recipients: report of three cases.

BACKGROUND: Neurologic complications occur in about 30% of renal transplant patients, infections being the most common. We encountered three such patients and present our experience in the management of such cases. CLINICAL MATERIAL: Three cases of brain abscess in renal transplant recipients are reported. These patients presented from 9-60 months after the transplant. One patient had a pyogenic abscess; in the second the organism identified was Nocardia asteroides; in the third, a fungal infection was responsible. In two patients excision of the abscess was done, while in one repeated aspirations with intracavitary antibiotics were used. All received systemic antimicrobial therapy. CONCLUSIONS: Central nervous system (CNS) complications, specifically infections, are quite common in renal transplant recipients, but reports of brain abscesses in these patients are very rare. The treatment options for such patients are discussed.

Adult↗

PubMed1997

Induction of native protein reactive antibodies by immunization with peptides containing linear B-cell epitopes defined by anti-porcine ZP3 beta monoclonal antibodies.

To identify pertinent target epitopes for contraceptive vaccine development, rabbit polyclonal antibodies were raised against four peptides synthesized from the deduced amino acid (aa) sequence of porcine zona pellucida macromolecule ZP3 beta and coupled to diphtheria toxoid (DT). Synthetic peptides consisted of: P1, 23-37 aa; P2, 164-179 aa with an additional C-terminal cysteine; P3, 246-263 aa with an extra C-terminal cysteine; and P4, 310-321 aa residues corresponding to pZP3 beta precursor protein. Selected sequences were based upon B cell epitopes identified previously by monoclonal antibodies. Immune sera reacted with their respective peptides and DT in an ELISA, and also recognized porcine SIZP and pZP3 beta both in ELISA and Western blot and zona pellucida of porcine oocytes in an indirect immunofluorescence assay. None of the four anti-peptide sera recognized pZP3 alpha in Western blot, emphasizing the specificity of these antibodies to pZP3 beta. The anti-peptide sera, individually, failed to inhibit in vitro attachment of boar sperm to antibody treated zona encased porcine oocytes. However, combinations of immune sera against peptides such as P1 + P4, P2 + P4 and P1 + P2 + P4, did significantly inhibit porcine sperm-oocyte interaction. These results identify combinations of peptides that could potentially be used in the design of an immunocontraceptive vaccine based upon synthetic peptides corresponding to pZP3 beta or its homologues in other species.

Amino Acid Sequence↗

PubMed1997

Delivery of emergency medical services in Kathmandu, Nepal.

We describe the delivery of emergency medical services in the developing country of Nepal and identify areas of need and potential collaboration. We conducted interviews with emergency department directors and staff, analyzed ED patient records, and prospectively surveyed a convenience sample of patients visiting three Kathmandu, Nepal, EDs. The three principal EDs in Kathmandu have a collective yearly volume exceeding 100,000 visits. Injury is the reason for more than 30% of all visits; 27% of ED patients are admitted. Equipment and emergency laboratory tests essential to the practice of emergency medicine are often unavailable. Emergency physicians receive no formal training in emergency medicine, and continuing medical educational opportunities are limited. We determined that the three EDs in Kathmandu provide high-volume, high-acuteness care. Emergency physicians lack critical resources to manage the breadth of clinical problems encountered. A substantial emergency medical infrastructure exists in Kathmandu from which to address emerging problems. Injury is currently the single greatest threat to public health and may benefit from a multi-level international collaborative approach.

Adolescent↗

PubMed1997

Antiemetic efficacy of ginger (Zingiber officinale) against cisplatin-induced emesis in dogs.

Effect of ginger (Zingiber officinale Roscoe, Zingiberaceae) extracts (acetone, 50% ethanolic and aqueous) were investigated for antiemetic activity against emesis induced by 3 mg/kg cisplatin (the 100% emetic dose i.v.) in-healthy mongrel dogs. The acetone and 50% ethanolic extract at the doses of 25, 50, 100 and 200 mg/kg p.o. exhibited significant protection while aqueous extract at these doses was ineffective against cisplatin emesis. The acetone extract was more effective than ethanolic extract. However, both were less effective when compared to 5-HT3 receptors antagonist-granisetron. Neither of the ginger extract was effective against apomorphine-induced emesis. The findings suggest that ginger could be an effective and cheap antiemetic adjunct to cancer chemotherapy.

Animals↗

PubMed1997

Noninvasive vascular imaging in the diagnosis and treatment of adventitial cystic disease of the popliteal artery.

This brief case report describes the successful outcome after surgical excision of multiple adventitial cysts of the popliteal artery in a 75-year-old man with rapidly worsening claudication. It highlights several unsettled points concerning the diagnosis, cause, and management of cystic adventitial disease of the popliteal artery and compares duplex ultrasound, computed tomography, and magnetic resonance angiography in the noninvasive diagnosis and treatment of this condition.

Aged↗

PubMed1997

Surgical complication outcome (SCOUT) score: a new method to evaluate quality of care in vascular surgery.

PURPOSE: Surgical outcome data are generally reported as raw morbidity and mortality rates, which do not necessarily reflect quality of surgical care. The Society for Vascular Surgery has led this area with recommendations by the Ad Hoc Committee on Reporting Standards to establish standardized methods of outcome assessment in vascular surgery. The purpose of this study was to evaluate a new method for evaluating the overall quality of surgical care, which includes surgeon, nursing, and hospital system performance. The goal of the method is to identify problem areas in surgical practice that can be targeted for focused improvement to improve outcome. METHODS: A database of more than 9000 general and vascular surgical cases was compiled over a 3-year period. Every postoperative complication was tabulated prospectively by a surgical nurse on a daily basis. Fifty clinically significant complication types specific for vascular surgery patients were identified from a list of 151 postoperative events by a panel of vascular surgeons and were grouped into nine broad categories (vascular, cardiac, pulmonary, etc.). These complications reflect the entire continuum of postoperative care, including surgeon, nursing, and hospital system performance. Each complication type was further stratified into four grades (mild, moderate, severe, death) and assigned a SCOUT severity score from 0 to 100 (0, no complication; 100, death) by the panel of surgeons. For case of data collection and monitoring of outcome, a software program was developed to run on a laptop computer and includes medical history, risk factors, pertinent laboratory data, and the preassigned SCOUT severity scores for measuring outcome. In this study, 170 major vascular procedures performed over the previous 12-month period were prospectively evaluated usig the SCOUT method in an attempt to more easily identify problem areas of practice. In-hospital morbidity and 30-day mortality results were examined. RESULTS: One hundred sixteen postoperative complications were identified in the 170 patients, with an overall morbidity rate of 51% and a 30-day mortality rate of 1.8%. Fifty-three percent of the complications were "mild" and required minimal intervention or observation only. Abdominal aortic aneurysm repair was associated with the highest morbidity rate (mean SCOUT score, 384.35), whereas distal extremity bypass grafting had the lowest morbidity rate (mean SCOUT score, 114.4). However, subgroup analysis demonstrated that cardiac events accounted for 52% of the morbidity associated with distal extremity bypass but only 34.7% of the morbidity associated with abdominal aortic aneurysm repair (p < 0.05). CONCLUSIONS: The SCOUT score is a new technical quality of care measure that can objectively quantify surgeon and other hospital system-related performance. The SCOUT score allows the surgeon to identify problem areas that can then be targeted for improvement to positively affect outcome.

Aged↗

PubMed1997

Use of muscle flap to cover infections of the carotid artery after carotid endarterectomy.

Wound infection after carotid endarterectomy is an extremely uncommon complication. This complication occurred in two of our patients in a series of 170 consecutive carotid endarterectomies over the last 3 years. There has been an increased use of prosthetic patch grafts to close carotid endarterectomy sites. However, the presence of infection in the setting of prosthetic graft material poses difficulties in management and may lead to life-threatening complications. Recent strategies for the management of wound infections (in cases where the artery/graft interface is intact) include the use of appropriate antibiotics, repeated wound debridement, and covering the tissue defect or the perigraft area with well-vascularized muscle flap. In this case report the use of sternocleidomastoid muscle flap as a coverage for the infected area is described. The use of sternocleidomastoid muscle flap helped control the infective process and secured the viability of the patched carotid arteries.

Anti-Bacterial Agents↗