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Biomedical subjects

K Singh

Publications and source records attributed to K Singh.

At least 379 records · Page 21Linked to original sources
PubMed1993

Disposition of thiorphan in DOCA-salt and spontaneously hypertensive rats.

Thiorphan was administered intravenously (i.v.) at 10 mg/kg to conscious rats in two different models of hypertension to allow a comparison of pharmacokinetics. The two models were: 1) Deoxycorticosterone acetate (DOCA)-salt uninephrectomized rats; 2) Spontaneously hypertensive rats (SHR), and their respective normotensive controls; 3) Sprague-Dawley (SD) rats; and 4) Wistar-Kyoto rats (WKY). Pharmacokinetic parameters were calculated for total and unbound thiorphan in plasma. In normotensive SD and WKY rats, the volume of distribution, clearance and plasma protein binding of thiorphan were not significantly different. Furthermore, the apparent elimination half-life was not significantly different for total or unbound thiorphan amongst all models. The volume of distribution and plasma clearance for both unbound and total thiorphan, however, were lower in DOCA-salt rats when compared to normotensive control rats by 61-66% and 46-51%, respectively. In contrast, pharmacokinetic parameters for both unbound and total thiorphan were not significantly different between SHR and WKY rats. These results indicate that reduced clearance of thiorphan in DOCA-salt rats may be due to the co-administration of DOCA-salt or altered renal function of the hypertrophic remaining kidney and not solely due to hypertension.

Animals↗
PubMed1993

Role of zipper in the management of abdominal sepsis.

BACKGROUND: Continuous peritoneal lavage, staged laparotomies and radical peritoneal debridement have been used to reduce mortality from severe abdominal sepsis. Recently, open abdomen technique using a 'zipper' with or without mesh for abdominal lavage has shown promising results. AIMS: To evaluate open abdominal technique using a zipper in patients with advanced diffuse peritonitis with impending or established multiple organ failure. METHODS: Modified open abdomen technique using zipper with or without mesh was used for abdominal closure in eight patients with severe generalized peritonitis (APACHE-II score range 27-30). RESULTS: Zipper was inserted at first laparotomy in three patients, at second exploration in four and at the time of third laparotomy in one case. Two patients required strips of mesh in addition to zipper. Six of eight patients survived and were discharged after an average period of 27 days. Two deaths were due to multisystem organ failure. In four patients additional surgical procedures like closure of perforation, temporary ileostomy and resection anastomosis of small bowel was carried out through the zipper. Zipper-mesh were removed an average of 10.5 days after insertion. Three patients developed incisional hernia at 6 months follow-up. CONCLUSION: This technique merits further controlled trials to ascertain its indications and benefits.

Abdomen↗
PubMed1993

Detection of Entamoeba histolytica antigens in stool in amebiasis.

BACKGROUND: Stool microscopy, the conventional method of diagnosing intestinal amebiasis, fails to detect Entamoeba histolytica in more than 30-40% of clinically suspected cases. Demonstration of parasite products in clinical specimens has been suggested as an alternative. However, the usefulness of demonstrating amebic antigen in the stools of clinical cases needs to be assessed. METHODS: A double-antibody sandwich enzyme linked immunosorbent assay (ELISA) using anti-trophozoite antibodies to capture E histolytica specific coproantigen(s) was carried out on stools obtained from 31 patients with microscopically confirmed non-dysenteric amebic colitis, 18 patients with intestinal parasites other than E histolytica and 41 apparently healthy subjects. RESULTS: The assay detected E histolytica specific coproantigen(s) in stools of 23 (74.2%) of 31 subjects with non-dysenteric amebic colitis, none of 18 with other parasitic infections and 1 (2.4%) of 41 apparently healthy subjects. CONCLUSION: Our results provide evidence for the presence of E histolytica specific coproantigen(s) in stool eluates from patients with amebic infection; this finding can be exploited for confirming ongoing amebic infection. However, the sensitivity of the assay needs to be improved by the use of relevant monospecific/monoclonal antibodies.

Animals↗
PubMed1993

Effects of breast feeding after resumption of menstruation on waiting time to next conception.

We investigate the association between breast feeding after resumption of menstruation and the duration from resumption of menses to the next conception. Data from a survey, "Breast-Feeding and Its Effect on Fertility," conducted in 1987 under the auspices of the Centre of Population Studies, Banaras Hindu University, India, were used. We used hazard models of conception rates after the return of menstruation with breast-feeding duration as a time-dependent covariate. The interaction of breast-feeding duration after resumption of menses and postpartum amenorrhea have a significant effect on the rate of conception after return of menses. After resumption of menstruation, when there is no breast feeding, the risk of conception increases with the increase in postpartum amenorrhea. However, breast feeding attenuates the effects of postpartum amenorrhea. These results suggest that breast feeding beyond the resumption of menstruation plays a significant role in the proximate determinants to reduce fertility.

Adult↗
PubMed1993

Iodixanol in abdominal digital subtraction angiography. A randomized, double-blind, parallel trial with iodixanol and iohexol.

The safety, tolerability and efficacy of iodixanol 270 mg I/ml were compared to those of iohexol 300 mg I/ml in a double-blind, randomized, parallel abdominal intra-arterial DSA phase III trial. Fifty-nine patients were included in the trial; 39 patients received iodixanol and 20 received iohexol. The mean volume of iodixanol administered was 235.8 ml (0.93 g I/kg b.w.) while the mean volume of iohexol was 254.7 ml (1.10 g I/kg b.w.). No differences in diagnostic information and radiographic density were apparent in spite of the difference in the concentration of iodine. No serious adverse events occurred. Four patients (10%) in the iodixanol group and 2 (10%) in the iohexol group experienced adverse events. Eight percent of the injections of iodixanol promoted discomfort, compared to 12% of the injections of iohexol. An increase in S-urea and S-creatinine was seen with both agents the first day after injection, but appeared to be less pronounced with iodixanol than with iohexol. Other serum tests revealed no changes of clinical importance. Both iodixanol and iohexol were found to be effective, safe and well tolerated contrast media for abdominal intra-arterial DSA.

Abdomen↗
PubMed1992

Differential processing of osteopontin transcripts in rat kidney- and osteoblast-derived cell lines.

Using immunoprecipitation and tryptic peptide microsequencing we confirmed the identity of normal rat kidney (NRK) cell-secreted 69-kDa major phosphoprotein as osteopontin (OP). We then immunoselected a 1.4-kilobase pair (kb) OP cDNA from a lambda gt11 library prepared from Kirsten sarcoma virus-transformed NRK (KNRK) cellular mRNA, using rabbit anti-69-kDa OP serum. Sequence analysis of this cDNA revealed the presence of a 52-nucleotide-long insert in the 5'-noncoding region, which was absent in OP cDNA cloned from the cDNA library of ROS 17/2.8 rat osteosarcoma cells. The insert sequence is flanked by putative intron splice junctions and is located 15-nucleotide upstream of the translational initiation site. An insert-specific 30-mer oligonucleotide probe hybridized to a single 1.5-kb RNA species from both NRK and KNRK cells, but not from ROS 17/2.8 cells. However, Southern analysis showed the presence of this insert sequence in the genomic DNA of both NRK and ROS 17/2.8 cells. Furthermore, PCR amplification of the insert-containing region using genomic DNAs from both NRK and ROS 17/2.8 cells gave products of identical size and sequence. Since OP is a single copy gene, these data provide strong evidence for differential cell type-specific processing of OP transcripts. In addition, we demonstrate that, in contrast to most transformed cells, levels of OP expression are significantly reduced in KNRK cells as compared to NRK cells.

Amino Acid Sequence↗
PubMed1992

A role for IGF-1 in the rescue of CNS neurons following hypoxic-ischemic injury.

Three days after unilateral hypoxic-ischemic injury in infant rats insulin-like growth factor 1 (IGF-1) production by astrocytes was enhanced in the injured region. This was associated with increased expression of mRNA for IGF binding protein-3 but not for binding protein-1. In adult rats a single lateral cerebroventricular injection of IGF-1 two hours following a similar injury markedly reduced neuronal loss. It is suggested that endogenous IGF-1 is neurotrophic and that centrally administered IGF-1 may have therapeutic potential for brain injury.

Animals↗
PubMed1992

Effect of Norplant implants on liver, lipid and carbohydrate metabolism.

In this study involving 100 women, the metabolic changes seen with Norplant use were evaluated. Besides a significant increase in serum bilirubin, there were no other changes in liver function to suggest possible hepatocellular dysfunction at the end of five years. Even the raised mean levels of bilirubin remained within the normal clinical range for the local population. As regards lipid metabolism, total triglycerides, cholesterol and LDL-cholesterol were decreased through the five years of Norplant use. The HDL-cholesterol showed a significant increase in the first year; it then decreased over the years to its preinsertion level at the end of five years. As a result, the HDL-cholesterol/Total cholesterol - HDL-cholesterol showed a significant increase in the first year and then decreased to almost its preinsertion value at the end of five years. The findings appear to indicate Norplant use not to be contributory to cardiovascular risk. The use of Norplant was not associated with any significant effect on carbohydrate metabolism.

Bilirubin↗
PubMed1992

Effect of long-term use of Norplant implants on haemostatic function.

This study describes the effects of Norplant on haemostatic function after 5 years of use in 97 women. There was a decrease in vitamin-K dependent Factors II, V, VII and reduction in fibrinolytic activity at 2 and 4 years of use. Increased platelet numbers and accelerated platelet aggregation were found throughout the 5 years of Norplant use, whilst raised alpha 2-Macroglobulin (a2-M) and antithrombin III (ATIII) antigen level were observed for up to 4 years of use. Prolonged Norplant use does not appear to activate the coagulation system and does not enhance a state of hypercoagulation.

Antigens↗
PubMed1992

Acceptability of Norplant implants for fertility regulation in Singapore.

The continuation rate at the end of this five-year clinical study was 60% with no accidental pregnancy occurring throughout the five years. The post-removal conception rate in women desiring pregnancy was 92% at the end of two years. The majority of acceptors described the overall experience with the implants as favourable. In fact, 75% of the women planning to use contraception after removal of the implants were going to use implants again.

Adult↗
PubMed1992

Acceptability of Norplant-2 rods as a method of family planning.

The Norplant-2 rod system consists of two silastic rods in which levonogestrel has been incorporated with the polymer. The continuation rate at the end of five year was 62%. No accidental pregnancies occurred throughout the five years of use. The post-removal conception rate in women desiring pregnancy was 70.8% at the end of two years. The majority of acceptors were happy with the rods and 86.8% expressed the desire to have another set of implants inserted following removal of the first set. The study shows the Norplant-2 rod system to be a well accepted method of family planning.

Adult↗
PubMed1992

Effect of Norplant-2 rods on liver, lipid and carbohydrate metabolism.

The effect of Norplant-2 rods on liver, lipid and carbohydrate metabolism was evaluated in 100 women using Norplant-2 rods. Besides a significant increase in serum bilirubin, there was no other obvious evidence to suggest any possible hepatocellular dysfunction with the use of Norplant-2 rods. As regards lipid metabolism, decreases in total triglycerides, cholesterol and LDL-cholesterol and HDL-cholesterol were initially seen. These parameters returned to their preinsertion mean at the end of five years. As a result, the value of the HDL-cholesterol/total cholesterol - HDL-cholesterol and LDL-cholesterol/HDL-cholesterol ratios remained around their preinsertion value at the end of five years. All this appears to indicate that the use of Norplant-2 rods is not directly contributory to cardiovascular risk. The use of Norplant-2 rods was not associated with any significant effect on carbohydrate metabolism.

Asia, Southeastern↗
PubMed1992

Hypoxia-ischemia induces transforming growth factor beta 1 mRNA in the infant rat brain.

Transforming growth factor beta 1 (TGF beta 1) mRNA expression was examined after hypoxia-ischemia in rat brains using in situ hybridization. Twenty-one-day-old Wistar rats had unilateral ligation of the right carotid artery followed by either 15 or 90 min inhalational hypoxia. Fifteen min of hypoxia resulted in moderate damage with selective neuronal loss in cortical layer 3 and in the hippocampus of the ligated hemisphere. Seventy-two hours after hypoxia TGF beta 1 expression was markedly increased above control levels in those sites. Levels were normal after 120 h. Ninety min of hypoxia led to an infarction of the lateral cerebral cortex and hippocampus of the ligated hemisphere. One hour after hypoxia TGF beta 1 mRNA was expressed in the hippocampus of the damaged side. Seventy-two and 120 h after hypoxia, expressing cells were found throughout the cerebral cortex, piriform cortex, striatum, thalamus and hippocampus of the infarcted side. These data show that TGF beta 1 mRNA expression is induced after a hypoxic-ischemic insult in the brain. TGF beta 1 may be involved in post-asphyxial repair mechanisms.

Animals↗
PubMed1992

Expression of insulin-like growth factor-binding protein 2 (IGF-BP 2) following transient hypoxia-ischemia in the infant rat brain.

Hypoxia-ischemia induced by unilateral carotid ligation followed by either 15 (moderate) or 90 (severe) min exposure to 8% oxygen was associated with induction of IGF-BP 2 mRNA expression. A specific rat IGF-BP 2 cDNA probe was used to determine the IGF-BP 2 mRNA distribution in brain sections using in situ hybridization. Untreated control rats and the non-ligated hemisphere in experimental rats expressed IGF-BP 2 mRNA in the choroid plexus, meninges and more weakly in the thalamus, hippocampus and cortical layer 5. Increased expression in experimental rats was limited to regions known to have neuronal damage. Three days after the moderate insult the signal was increased in the CA1/2 region of the hippocampus and thalamus of the ligated side. Three days after the severe insult IGF-BP 2 expression was found surrounding the infarcted regions while by 5 days after severe insult the whole infarcted volume showed induction. The results suggest a role for the IGFs in the post-asphyxial response. IGF-BP 2 may alter the bio-availability of IGF 1 or 2 or modulate their actions in the area of infarction, and thus promote cerebral repair and recovery.

Animals↗
PubMed1992

Influence of the chemical composition on gamma ray attenuation by fatty acids.

The dependence of gamma ray attenuation on the chemical composition of fatty acids is investigated in the energy range from 10(-3) to 10(5) MeV. The mass attenuation coefficients (muF) and effective atomic numbers (Zeff) have been calculated for 27 different fatty acids. They show appreciable variation with the chemical composition of fatty acids in the region of gamma ray energies from 10(-3) to 10(5) MeV.

Fatty Acids↗
PubMed1992

Optimal number of biopsy specimens in the diagnosis of carcinoma of the oesophagus.

The study evaluated 48 patients with carcinoma of the oesophagus to assess the optimal number of biopsy specimens required to obtain the highest yield. Eight specimens were obtained from each patient and two specimens were placed serially in each of four vials. The first vial provided a positive diagnosis in 95.8% of cases. The addition of two more specimens (second vial) increased the yield to 97.9% and the fifth and sixth specimens increased the positive yield to 100%. There was no statistically significant difference in the yield according to the site and the type of growth.

Adult↗