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Biomedical subjects

N Gupta

Publications and source records attributed to N Gupta.

At least 199 records · Page 11Linked to original sources
PubMed1998

Nocturnal elevation of intraocular pressure in young adults.

PURPOSE: To distinguish 24-hour (circadian) and postural effects on intraocular pressure (IOP) in healthy young adults. METHODS: Thirty-three volunteers were housed in a sleep laboratory for 1 day under a strictly controlled 16-hour light and 8-hour dark environment. Sleep was encouraged in the dark period. Intraocular pressure was measured in each eye every 2 hours using a pneumatonometer. Researchers used night-vision goggles to perform IOP measurements in the dark, while the subject's light exposure was minimized. In the first group of 12 subjects, measurements were taken with subjects in the sitting position during the light-wake period and supine during the dark period. In the second group of 21 subjects, all IOP measurements were taken with the subjects supine. RESULTS: Average IOP was significantly higher in the dark period than in the light-wake period in both groups. The lowest IOP occurred in the last light-wake measurement, and the peak IOP occurred in the last dark measurement. The trough-peak difference in IOP was 8.2+/-1.4 mm Hg (mean +/- SEM) in the first group. Intraocular pressure changed sharply at the transitions between light and dark. In the second group, the trough-peak IOP difference was 3.8+/-0.9 mm Hg. Intraocular pressure changed gradually throughout the 24-hour period. In comparison with the sitting IOP in the first group, the supine IOP in the second group was significantly higher during the light-wake period. CONCLUSIONS: Circadian rhythms of IOP were shown in young adults, with the peaks occurring in the late dark period. A nocturnal IOP elevation can appear independent of body position change, but change of posture from upright to recumbent may contribute to the relative nocturnal IOP elevation.

Adolescent↗
PubMed1998

Ganciclovir-associated hypercalcemia in a renal transplant patient.

We describe a renal transplant patient who developed hypercalcemia during treatment with ganciclovir for cytomegaloviral (CMV) infection. To our knowledge such an association has not previously been reported. Hypercalcemia was associated with low levels of serum parathormone (PTH) and an increase in 1,25 dihydroxy vitamin D concentrations. The mechanism(s) of ganciclovir-associated hypercalcemia remains unclear.

Antiviral Agents↗
PubMed1997

A recombinant human scFv anti-Rh(D) antibody with multiple valences using a C-terminal fragment of C4-binding protein.

Monomeric recombinant molecules prove generally unsatisfactory for in vivo use. Most biological systems are indeed multivalent either structurally, associating different chains, or functionally, when cross-linked by their ligands. Mimicking natural molecules for immune intervention implies the need for multimerizing systems to create multivalent molecules capable of interfering with physiological processing. A multivalent anti-Rh(D) recombinant protein has been designed by reconstructing the antibody binding site of a human monoclonal anti-Rh(D) antibody as a single chain Fv mini antibody, then multimerizing it by inserting at its C-terminal end the C-terminal part of the C4 binding protein (C4bp) alpha chain, which is responsible for the octamer multimerization of that molecule. This soluble multivalent recombinant molecule was functional, bound red blood cells (RBCs), agglutinated them, and did not activate complement. This demonstration model opens the way for future in vivo use of multivalent molecules associating antibody valences and other functional molecules for cell targeting, imaging, or removal of cells such as Rh(D)-positive RBCs for preventing Rh alloimmunization.

Amino Acid Sequence↗
PubMed1997

Negative signaling pathways of the killer cell inhibitory receptor and Fc gamma RIIb1 require distinct phosphatases.

Inhibition of natural killer (NK) cells by the killer cell inhibitory receptor (KIR) involves recruitment of the tyrosine phosphatase SHP-1 by KIR and is prevented by expression of a dominant negative SHP-1 mutant. Another inhibitory receptor, the low affinity Fc receptor for immunoglobulin G (IgG) (Fc gamma RIIb1), has been shown to bind SHP-1 when cocross-linked with the antigen receptor on B cells (BCR). However, coligation of Fc gamma RIIb1 with BCR and with Fc epsilon RI on mast cells leads to recruitment of the inositol 5' phosphatase SHIP and to inhibition of mast cells from SHP-1-deficient mice. In this study, we evaluated the ability of these two inhibitory receptors to block target cell lysis by NK cells, and the contribution of SHP-1 and SHIP to inhibition. Recombinant vaccinia viruses encoding chimeric receptors and dominant negative mutants of SHP-1 and SHIP were used for expression in mouse and human NK cells. When the KIR cytoplasmic tail was replaced by that of Fc gamma RIIb1, recognition of HLA class I on target cells by the extracellular domain resulted in inhibition. A dominant negative mutant of SHP-1 reverted the inhibition mediated by the KIR cytoplasmic tail but not that mediated by Fc gamma RIIb1. In contrast, a dominant negative mutant of SHIP reverted only the inhibition mediated by the Fc gamma RIIb1 tail, providing functional evidence that SHIP plays a role in the Fc gamma RIIb1-mediated negative signal. These data demonstrate that inhibition of NK cells by KIR involves primarily the tyrosine phosphatase SHP-1, whereas inhibition mediated by Fc gamma RIIb1 requires the inositol phosphatase SHIP.

Animals↗
PubMed1997

Cytotoxicity and cell-cycle effects of paclitaxel when used as a single agent and in combination with ionizing radiation.

PURPOSE: This study aimed to determine the extent of paclitaxel-induced cytotoxicity and cell-cycle perturbations when used alone and in combination with radiation in human glioma cells. METHODS AND MATERIALS: The effect of paclitaxel alone on three human glioma cells lines--SF-126, U-87 MG, and U-251 MG--was assessed after 24, 48, 72, or 96 h treatment. For experiments in combination with radiation, cells were exposed to either a long (48-h) or short (8-h) duration of paclitaxel treatment prior to irradiation. Cell survival was determined by clonogenic assay. Cell cycle perturbations were assessed by using flow cytometry to measure the proportion of cells in G1, S, and G2/M phases. RESULTS: When cells were treated with paclitaxel alone for > or = 24 h, cytotoxicity increased up to a threshold dose, after which it plateaued. When treatment duration was < or = 24 h, cytotoxicity was appreciably greater in U-251 MG cells than in SF-126 and U-87 MG cells. After 24 h of paclitaxel treatment, cells in plateau phase growth had increased survival compared to cells in log phase growth. In contrast, after 8 h paclitaxel treatment, mitotic cells had reduced survival compared to cells from an asynchronous population. Cell-cycle perturbations were consistent with the presence of a mitotic block after paclitaxel treatment, although changes in other cell-cycle phase fractions varied among cell lines. For experiments in combination with radiation, cytotoxicity was increased when cells were irradiated after 48 h of paclitaxel treatment but not after 8 h of treatment. CONCLUSION: The duration of paclitaxel treatment and the location of cells in the cell cycle modify the degree of radiation cytotoxicity. The mechanisms of paclitaxel cytotoxicity are likely to be multifactorial because varying effects are seen in different cell lines. Furthermore, it is clear that simply increasing the number of cells in G2/M is insufficient in itself to increase the response of cells to radiation.

Antineoplastic Agents, Phytogenic↗
PubMed1997

Severe vision loss and neovascular glaucoma complicating superior ophthalmic vein approach to carotid-cavernous sinus fistula.

PURPOSE: To report a patient with unilateral vision loss and neovascular glaucoma after attempted superior ophthalmic vein embolization in the treatment of a carotid-cavernous sinus fistula. METHODS: A 69-year-old man with a history of a left dural carotid-cavernous sinus fistula underwent attempted treatment with superior ophthalmic vein embolization. The procedure was unsuccessful, and the left superior ophthalmic vein was ligated. RESULTS: Uncontrolled left proptosis and intraocular pressure necessitated urgent orbital decompression with severe vision loss and neovascular glaucoma. CONCLUSION: Superior ophthalmic vein embolization in the management of carotid-cavernous fistula may be associated with vision-threatening complications.

Aged↗
PubMed1997

Management of giardiasis by a herbal drug 'Pippali Rasayana': a clinical study.

Pippali Rasayana (PR), an Indian ayurvedic drug prepared from Palash (Butea monosperma (Lamk) Kuntze; Leguminaceae) and Pippali (Piper longum L.; Piperaceae), was administered at a dose of 1 g p.o. three times daily for a period of 15 days to patients (25 treated, 25 placebo controls) suffering from giardiasis with clinical signs and symptoms, and stools positive for trophozoites/cysts of Giardia lamblia. After 15 days of drug treatment there was a complete disappearance of G. lamblia (trophozoites/cysts) from the stools of 23 out of 25 patients. General signs and symptoms of ill health and abdominal discomfort, presence of mucus, pus cells and RBCs were significantly reduced. There was a marked improvement in the clinical and haematological profile of the patients. Spontaneous recovery in 20% cases was recorded in placebo controls.

Adjuvants, Immunologic↗
PubMed1997

New definitions of glaucoma.

At this time, there is no comprehensive and specific definition of glaucoma. Diagnostic tests such as retinal nerve fiber layer observation, scanning laser polarimetry, and confocal scanning laser tomography may improve the diagnosis and detection of glaucoma. Also, new functional tests, including short-wave-length automated perimetry, may provide better detection of glaucoma.

Disease Progression↗
PubMed1997

Comparison of immunomodulation by cyclosporin A and azathioprine on pancreatic xenograft survival.

Prolonged survival of pancreatic xenografts in the muscles of diabetic rabbits under the immunomodulation of cyclosporin A and azathioprine was achieved. The mean graft survival time (as assessed by euglycemic status and histopathological findings) in Group A (azathioprine treated) was 36 days, in Group B (cyclosporin A treated) it was 69 days, and the difference was significant (p < 0.001). Adequate immunosuppression helps the pancreatic xenograft to normalize the blood glucose level (BGL) by prolonging its survival time. Our study demonstrates that xenotransplanted islet cells in a natural environment (pancreatic tissue in the form of thin slices) survive and function adequately in immunosuppressed recipients, and addition of cyclosporin A significantly prolongs survival of the xenograft. This discordant xenotransplantation model may be useful for future xenotransplantation studies.

Adjuvants, Immunologic↗
PubMed1997

Lipid-lowering effects of fluvastatin in renal transplant patients. A clinical observation.

A Atherosclerosis-related cardiovascular disease remains an important cause of morbidity and mortality in renal transplant patients. We assessed the efficacy and safety of the newer synthetic HMG-CoA reductase inhibitor, fluvastatin, in 12 renal transplant patients who remained hypercholesterolemic, despite having been on the American Heart Association (AHA) Step I diet for 6 weeks. At 8 weeks, compared to the control phase, fluvastatin therapy, 20 mg/day, reduced the total cholesterol (TC) from 321 +/- 57 [+/-SD] to 301 +/- 123 mg/dl (p = 0.3); low-density lipoprotein cholesterol (LDL-C), from 209 +/- 56 to 176 +/- 81 mg/dl (p = 0.2); and the triglyceride (TG) levels from 343 +/- 119 to 277 +/- 117 mg/dl (p = 0.06); all these changes were statistically insignificant. However, the therapy significantly increased the high-density lipoprotein cholesterol (HDL-C) from 37 +/- 11 to 46 +/- 13 mg/dl (p = 0.006). During this short-term treatment period no adverse biochemical effects were noted with the therapy.

Adult↗
PubMed1997

Effect of sodium stibogluconate on hepatic mixed function oxidase system and marker enzymes of golden hamsters during Leishmania donovani infection.

During L. donovani infection in golden hamsters, tremendous hepatic damage was observed as apparent from increased activities of glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, succinate dehydrogenase, glucose-6-phosphatase and acid ribonuclease. The levels of cytochrome P-450 and related monooxygenases, viz. aniline hydroxylase and aminopyrine-N-demethylase registered significant decrease in infected animals. Sodium stibogluconate, a standard antileishmanial drug, though caused the removal of parasites from infected tissues, but did not help in the recovery of deranged hepatic markers. The results explain the higher mortality of stibanate treated infected animals as compared to untreated animals infected with L. donovani.

Animals↗
PubMed1997

Patterns of various modes of delivery in relation to presence of different risk factors in term pregnant mothers--a case-control study.

A case-control study, was carried out, which aimed to determine whether a relation exists between risk factors present in mother and the mode of delivery i.e., outcome. Cases were those mothers who had one or more risk factors present during pregnancy (namely, short stature, malpresentation, antepartum haemorrhage, pre-eclamptic toxaemia/eclampsia, anaemia-haemoglobin less than 10 g/dl, twins, bad obstetric history, prolonged pregnancy, history of previous caesarean section and instrumental delivery, pregnancy associated with general diseases, prolonged difficult labour and RH-iso-immunisation). Controls were those mothers who did not have any of the above mentioned risk factors. Total of 250 cases and 250 controls were taken. Results showed that surgical and instrumental deliveries were strongly associated with presence of risk factors (odd's ratio: 5.94; attributable risks: 72%). Out of risk factors among cases, most common indication of caesarean section, was previous caesarean section followed by malpresentation, prolonged difficult labour and short statured mothers in descending order.

Case-Control Studies↗
PubMed1996

Internal pudendal flap anoplasty for severe anal stenosis. Report of a case.

PURPOSE: A technique for introducing anoderm into the anal canal is described. METHODS: An internal pudendal flap was used. RESULTS: This technique was totally successful in alleviating anal stenosis and maintaining fecal continence. CONCLUSION: Internal pudendal flap should be in the armamentarium of the colon and rectal surgeon for treating severe anal stenosis.

Aged↗
PubMed1996

Role of positron emission tomography scanning in evaluating gastrointestinal neoplasms.

Positron Emission Tomography (PET) is rapidly evolving into a useful imaging modality for early and accurate detection of malignant tumor sites. Several recent studies have documented improved efficacy of detecting recurrent colorectal and hepatic (primary and metastatic) tumor sites with a sensitivity ranging from 92% to 100% and an accuracy of 90% to 96%. PET-FDG imaging using 2-[18F]-fluoro-2-deoxy-D-glucose has been found to be superior to computed tomography (CT) in detecting recurrent colorectal, hepatic, and abdominopelvic recurrent tumor sites from different primary cancers. PET-FDG imaging can be a cost-effective tool in the screening of patients with an elevated carcinoembryonic antigen and/or equivocal CT findings and suspected colorectal cancer. The role of PET scanning using FDG or C-11-5-HTP or C-11-L-DOPA appears promising in pancreatic carcinoma and functional endocrine tumors. Further studies are being carried out to assess the role of PET scanning in other gastrointestinal cancers.

Colorectal Neoplasms↗