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Biomedical subjects

V K Gupta

Publications and source records attributed to V K Gupta.

At least 55 records · Page 3Linked to original sources
PubMed2001

Process development for the removal of lead and chromium from aqueous solutions using red mud--an aluminium industry waste.

Red mud, an aluminium industry waste, has been converted into an inexpensive and efficient adsorbent and used for the removal of lead and chromium from aqueous solutions. Effect of various factors on the removal of these metal ions from water (e.g. pH, adsorbent dose, adsorbate concentration, temperature, particle size, etc.) has been studied and discussed. The effect of presence of other metal ions/surfactants on the removal of Pb2+ and Cr6+ has also been studied. The material exhibits good adsorption capacity and the data follow both Freundlich and Langmuir models. Thermodynamic parameters indicate the feasibility of the process. Kinetic studies have been performed to understand the mechanism of adsorption. Dynamic modelling of lead and chromium removal on red mud has been undertaken and found to follow first-order kinetics. The rate constant and mass transfer coefficient have also been evaluated under optimum conditions of removal in order to understand the mechanism. Column studies have been carried out to compare these with batch capacities. The recovery of Pb2+ and Cr6+ and chemical regeneration of the spent column have also been tried.

Aluminum↗
PubMed2001

Biosorption of chromium(VI) from aqueous solutions by green algae Spirogyra species.

Biosorption of heavy metals is an effective technology for the treatment of industrial wastewaters. Results are presented showing the sorption of Cr(VI) from solutions by biomass of filamentous algae Spirogyra species. Batch experiments were conducted to determine the adsorption properties of the biomass and it was observed that the adsorption capacity of the biomass strongly depends on equilibrium pH. Equilibrium isotherms were also obtained and maximum removal of Cr(VI) was around 14.7 x 10(3) mg metal, kg of dry weight biomass at a pH of 2.0 in 120 min with 5 mg/l of initial concentration. The results indicated that the biomass of Spirogyra species is suitable for the development of efficient biosorbent for the removal and recovery of Cr(VI) from wastewater.

Adsorption↗
PubMed2001

Controlled-release tablets from carrageenans: effect of formulation, storage and dissolution factors.

The purpose of this study was to investigate the potential of two carrageenans, iota-carrageenan and lambda-carrageenan for the preparation of controlled-release tablets. Tablets were compressed on a Carver press and the effect of formulation factors, moisture, and storage on the release of theophylline was studied. The effect of sodium chloride in the tablet formulation and a change in the ionic strength of the dissolution media was studied on the release of three model drugs. The release rate increased both with an increase in tablet diameter and increase in drug to carrageenan ratio in the tablets. The two lubricants studied had a negligible effect on the rate of drug release at their commonly used concentrations. Moisture content of carrageenans, storage of tablets at 37 degrees C/75% RH for 3 months, and incorporation of 10% sodium chloride in the tablets did not have any significant effect on the release rate. The change in ionic strength of simulated gastric fluid altered the release rate whereas the ionic strength of simulated intestinal fluid did not have a significant effect on the release rate. Carrageenan tablets were relatively insensitive to small changes in formulation parameters and dissolution conditions.

Carrageenan↗
PubMed2001

Pyridoxine-dependent seizures: a case report and a critical review of the literature.

Pyridoxine-dependent seizures are a recognized, although rare, cause of intractable seizures in neonates. Patients with this autosomal recessive disorder have recurrent seizures that are resistant to conventional anticonvulsants but respond dramatically to intravenous administration of pyridoxine. Life-long supplementation with pyridoxine is required to prevent seizure recurrence. In the absence of a biological marker for the disease, clinical diagnosis is often delayed and severe neurological sequelae are common. Herein, we report on the clinical course of a neonate with pyridoxine-dependent seizures. Delayed normalization of the electroencephalogram and a normal developmental outcome (at 15 months of age) on a dose of 10 mg/kg pyridoxine are distinctive features of the present case. We also review recent clinical observations and neurochemical studies that have added to our knowledge of this disorder.

Electroencephalography↗
PubMed2001

The association of antiphospholipid antibodies with ischaemic stroke and myocardial infarction in young and their correlation: a preliminary study.

AIM: The possible etiological role of antiphospholipid antibodies (APA) in thrombotic events on arterial side has become subject of interest. The present study was undertaken to determine the association and possible etiological role of APA in young Indian patients with acute ischaemic stroke and myocardial infarction (MI). MATERIAL AND METHODS: Forty six patients < 40 years of age including 22 with ischaemic stroke (excluding those with rheumatic heart disease and SLE), 24 with an acute MI and 21 age and sex matched healthy controls were enrolled in the study. All the patients and the controls were tested for the presence of lupus anticoagulant (LA) by a lupus sensitive activated partial thromboplastin time (APTT) and kaolin clotting time (KCT) and anti-caridiolipin antibodies (aCL) of IgM and IgG types using an ELISA technique. RESULTS: The screening tests for LA with APTT and KCT were negative in all the patients and the normal controls. In the stroke subgroup 18.18% patients (4/22) and in MI subgroup 4.16% (1/24) patients had raised aCL titers with statistically significant association only for stroke subgroup (p=0.0201) and not for MI subgroup. Significantly higher proportion of aCL positive cases were found in patients without any risk factor for atherosclerosis (4/12), compared to patients with one or more risk factor for atherosclerosis (1/34), p=0.001. CONCLUSION: Younger patients without identifiable risk factors for atheroscerosis presenting with stroke, are more likely to have an underlying antiphospholipid syndrome (APLS) as the etiology, and should be screened for it. No such association however was observed for MI patients.

Adolescent↗
PubMed2001

Three years of cadaveric renal transplantation.

AIM: To study patient and graft outcome and donor characteristics in cadaveric renal transplantation. MATERIAL AND METHODS: Fifty nine patients (35 males and 24 females) who underwent cadaveric renal transplantation between Oct'95 and Nov'98 were analysed. The recovery of renal function was correlated with the type and duration of dialysis. The number of rejections, donor characteristics and patient and graft survival was studied. RESULTS: Fifty nine patients were followed for a mean period of 14.58 months (SD 10.73), their age ranged from 17 to 64 years. Ten patients had primary graft failure, out of which four died and six are on maintenance dialysis. Seven died of other causes. Twelve patients had been on CAPD and 47 were on haemodialysis. Recovery of renal function was earlier in the haemodialysis group (mean 19.29 days SD 16.97) than in the CAPD group (31.6 days SD 32.3 days). But the difference was not statistically significant (p=0.36). The age of the donors ranged from 2 to 72 years (mean 42.8, SD 17.3). Seventeen died of CVA, 16 died of head injury, and one died of sedative overdose. Dual kidney transplant was done in nine patients of whom five have adequate graft function. CONCLUSION: Follow up for a mean period of 14.58 months shows patient survival of 81.3% and graft survival 72.8% with no significant difference in recovery of renal function between CAPD and HD groups. Poor results are due to HLA mismatch leading to rejection. The majority of the deaths were related to septicaemia.

Adolescent↗
PubMed2000

NM-3, an isocoumarin, increases the antitumor effects of radiotherapy without toxicity.

We examined the effects of a new antiangiogenic isocoumarin, NM-3, as a radiation modifier in vitro and in vivo. The present studies demonstrate that NM-3 is cytotoxic to human umbilical vein endothelial cells (HUVECs) but not to Lewis lung carcinoma (LLC) cells nor Seg-1, esophageal adenocarcinoma cells, in clonogenic survival assays. When HUVEC cultures are treated with NM-3 combined with ionizing radiation (IR), additive cytotoxicity is observed. In addition, the combination of NM-3 and IR inhibits HUVEC migration to a greater extent than either treatment alone. The effects of treatment with NM-3 and IR were also evaluated in tumor model systems. C57BL/6 female mice bearing LLC tumors were given injections for 4 consecutive days with NM-3 (25 mg/kg/day) and treated with IR (20 Gy) for 2 consecutive days. Combined treatment with NM-3 and IR significantly reduced mean tumor volume compared with either treatment alone. An increase in local tumor control was also observed in LLC tumors in mice receiving NM-3/IR therapy. When athymic nude mice bearing Seg-1 tumor xenografts were treated with NM-3 (100 mg/kg/day for 4 days) and 20 Gy (four 5 Gy fractions), significant tumor regression was observed after combined treatment (NM-3 and IR) compared with IR alone. Importantly, no increase in systemic or local tissue toxicity was observed after combined treatment (NM-3 and IR) when compared with IR alone. The bioavailability and nontoxic profile of NM-3 suggests that the efficacy of this agent should be tested in clinical radiotherapy.

Adenocarcinoma↗
PubMed2000

Comparative evaluation of a field-based dot-ELISA kit with three other serological tests for the detection of Brucella antibodies in goats.

A dot-ELISA (d-ELISA) test was evaluated and compared with the serum agglutination test (SAT), micro-complement fixation test (CFT) and a plate-ELISA (p-ELISA) for field use in screening herds of goats against brucellosis. During the standardization of the dot-ELISA kit on 1732 caprine serum samples, 1571 samples out of 1666 were found to be negative in d-ELISA, SAT and micro-CFT, while 59 were positive in different combinations. Of a further 66 serum samples, 34 were negative and 31 were positive in different combinations in d-ELISA, SAT, micro-CFT and p-ELISA. A total of 1584 goats belonging to different herds were then screened for brucellosis. Of the 694 serum samples screened in the first batch using d-ELISA, a positive reaction was observed in 26 cases. Further screening of these cases revealed 13 and 21 goats as positive reactors in SAT and CFT, respectively. In a second batch of 890 goats there were 109 positive reactors in d-ELISA. Among these 109 goats, 34, 40 and 80 goats were positive reactors in SAT, CFT and p-ELISA, respectively. The results of d-ELISA correlated well with those of p-ELISA. Dot-ELISA was found to be a more suitable and rapid test for screening large numbers of goats in the field.

Agglutination Tests↗
PubMed1999

Multiple regions of deletion on chromosome arm 13q in head-and-neck squamous-cell carcinoma.

Several lines of evidence suggest that the progression of head-and-neck squamous-cell carcinoma (HNSCC) involves inactivation of at least one and possibly several tumor-suppressor genes on the long arm of chromosome 13. The fact that neither Rb1 nor BRCA2 appears to be inactivated in the majority of head-and-neck cancers suggests that novel tumor-suppressor genes are involved. We have used microsatellite repeat polymorphisms and PCR to detect several distinct minimal regions of deletion on 13q in supraglottic and oral squamous-cell carcinomas. One region maps to 13q34, the second to 13q14.3 and a potential third region, not reported in previous studies, maps to 13q12.1. Overall, 69% of the 145 tumors examined demonstrated allelic loss at one or more loci on 13q. We investigated whether a novel suppressor candidate mapping to 13q14. 3-q21, leukemia-associated gene 1, might also be involved in the progression of squamous-cell carcinomas. Multiplexed PCR revealed homozygous deletion of leu1 in one oral cavity tumor. This suggests that this gene or one nearby may be the actual target of deletions in this region of the chromosome arm.

3-Isopropylmalate Dehydrogenase↗
PubMed1999

Localization of a putative tumor suppressor gene in the sub-telomeric region of chromosome 8p.

Several regions of chromosome arm 8p are frequently deleted in a variety of human malignancies including those of the prostate, head and neck, lung, and colon, suggesting that there is more than one tumor suppressor gene on this chromosome arm. Both laryngeal and oral squamous cell carcinomas exhibit three distinct and nonoverlapping regions of deletion on 8p. We have further refined the localization of the putative suppressor in 8p23 by using eight microsatellite loci to create a high resolution deletion map of 150 squamous cell carcinomas of the larynx and oral cavity. These new data demonstrate that there are two distinct classes of deletion within this relatively small region of the chromosome and suggest two possible locations for the gene within the D8S264 to D8S1788 interval. We also determined that there is little difference between the allelic loss frequencies of microsatellites mapping near the telomeric ends of other chromosome arms and loci mapping to more centromere proximal regions of the same arm. These data suggest that the high allelic loss frequencies seen at 8p23 loci are not the result of a generalized instability of chromosome ends and are instead consistent with the activation of a specific suppressor gene.

Carcinoma, Squamous Cell↗
PubMed1999

Percutaneous absorption of sunscreens through micro-yucatan pig skin in vitro.

PURPOSE: The objectives of this study were to develop an in vitro model for studying sunscreen permeation in skin, and evaluate the influence of formulation differences. METHODS: The sunscreens studied were two of the most widely used agents, octyl methoxycinnamate (OMC) and benzophenone-3. Preparations containing radiolabeled actives were applied to micro-Yucatan pig skin dermatomed to a thickness of 250-300 microm as a finite dose in a flow-through diffusion system. At the end of each experiment the amounts removed by washing, retained inside stratum corneum (SC) and penetrated into receptor and viable skin were determined. RESULTS: The two sunscreens reached a peak level in SC within an hour. Benzophenone-3 penetrated skin to a greater extent than OMC. The opposite was true when comparisons of SC retention were made. The ratio of retained to penetrated amount of sunscreens from a hydroalcoholic formulation at the end of 10 hours was higher when the sunscreens were present together than alone. CONCLUSIONS: Despite the highly lipophilic nature of sunscreens, particularly OMC, SC is the rate limiting skin layer for penetration. Penetration and SC retention were formulation dependent. The ratio of SC content to the amount penetrated is a useful tool for evaluating sunscreen permeation.

Animals↗
PubMed1999

Suprasellar arachnoid cyst presenting with precocious puberty : report of two cases.

Suprasellar arachnoid cysts (SSAC) are uncommon intracranial lesions. Two patients of SSAC presenting with precocious puberty are described. In both the cases partial excision of the cyst wall, through a pterional craniotomy, establishing communication with the basal subarachnoid spaces was carried out. The endocrinological symptoms regressed after surgery. The clinical presentations of SSAC and the treatment options available are reviewed.

Child↗
PubMed1998

Optical amplification of ligand-receptor binding using liquid crystals.

Liquid crystals (LCs) were used to amplify and transduce receptor-mediated binding of proteins at surfaces into optical outputs. Spontaneously organized surfaces were designed so that protein molecules, upon binding to ligands hosted on these surfaces, triggered changes in the orientations of 1- to 20-micrometer-thick films of supported LCs, thus corresponding to a reorientation of approximately 10(5) to 10(6) mesogens per protein. Binding-induced changes in the intensity of light transmitted through the LC were easily seen with the naked eye and could be further amplified by using surfaces designed so that protein-ligand recognition causes twisted nematic LCs to untwist. This approach to the detection of ligand-receptor binding does not require labeling of the analyte, does not require the use of electroanalytical apparatus, provides a spatial resolution of micrometers, and is sufficiently simple that it may find use in biochemical assays and imaging of spatially resolved chemical libraries.

Anisotropy↗
PubMed1998

Two B cell subpopulations have distinct recirculation characteristics.

This report describes two subpopulations of B cells in sheep. These subpopulations have distinct recirculation characteristics and tissue distributions. Phenotypically the populations are distinguished by their differential expression of the complement receptors, CD21 (CR2) and CD11b/CD18 (CR3). CD11b+ B cells are surface (s)IgMhi, co-express CD11c but are L-selectin negative. They populate the splenic marginal zone but are absent from splenic and ileal Peyer's patch (IPP) follicles and both afferent and efferent lymph compartments. Fluorescent tracing experiments showed that the CD11b+ B cells are non-recirculating as they did not appear in lymph after intravenous inoculation but are restricted to the blood and spleen. The CD11b-negative population expresses a conformational determinant of CD21 that is recognized by the monoclonal antibody Du 2-74. These cells are sIgMlo and co-express L-selectin. They populate the splenic and IPP follicles, are absent from the splenic marginal zone and are the only B cells in afferent lymph, efferent lymph and all lymph nodes. Fluorescence tracing experiments showed that the CD21 B cells are recirculating cells with their entry into efferent lymph being detectable by 16 h and peaking at 24-30 h. These data suggest that there are at least two lineages of B cells in the sheep with different phenotypic, functional and recirculation characteristics.

Animals↗
PubMed1998

99m-Technetium sestamibi localized solitary parathyroid adenoma as an indication for limited unilateral surgical exploration.

BACKGROUND: Because of its successful localization of solitary adenomas, 99m-Technetium sestamibi (MIBI) may challenge the standard operation for primary hyperparathyroidism. METHODS: Thirty-five consecutive patients underwent preoperative MIBI localization to optimize a surgical approach. Single-site localization in 21 patients directed a limited unilateral neck exploration (UNE) with adenomectomy and ipsilateral gland biopsy. Fourteen patients who did not localize underwent bilateral neck exploration (BNE). Conversion to a bilateral operation was required in 1 UNE patient because no adenoma was found on that side. RESULTS: There were no significant differences in preoperative and postoperative serological markers between the two groups. However, the total operative time for UNE (49 +/- 21 minutes) was significantly less than for BNE (103 +/- 45 minutes; P <0.001). CONCLUSIONS: Preoperative MIBI scan-directed limited unilateral neck operation may be used reliably for primary hyperparathyroidism due to a single adenoma, and thereby reduce operative time, extent of surgical dissection, and risk.

Adenoma↗