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Biomedical subjects

K Singh

Publications and source records attributed to K Singh.

At least 235 records · Page 13Linked to original sources
PubMed1998

The role of prophylactic iron supplementation in pregnancy.

The prevalence, causes and role of iron prophylaxis in pregnant women was studied. All women delivered at the National University Hospital, Singapore in 1993 had their haemoglobin estimated. If it was less than 11 g/dl, blood was taken for serum iron, ferritin, transferrin, red cell zinc protoporphyrin, serum folate, vitamin B12 and thalassemia screen to establish cause of anaemia. Data was also collected with regards to their antenatal progress and iron prophylaxis. Logistic regression, Chi-square test, Fischer's exact test and Mantel-Haenszel tests were also used to assess the relationships between categorical variables. The prevalence of anaemia at first antenatal visit was 20.6% while the prevalence of anaemia at delivery was 15.3%. The commonest cause of the anaemia in pregnancy was due to iron deficiency (81.3%). In the non-anaemic group, 90.7% were on prophylactic iron supplements compared to 50.6% in the anaemic group (P < 0.001). Of the 752 women found to be anaemic at booking, 591 received prophylactic iron supplements while 161 women did not. A total of 166 (28.1%) of those with iron supplements were anaemic at delivery, whereas 140 (87.0%) of those who did not receive prophylactic iron remained anaemic at delivery (P < 0.001). Of the 2516 non-anaemic women who received prophylactic iron, 118 (4.7%) developed anaemia at delivery while 133 (34.1%) out of the 390 women who did not receive prophylactic iron were anaemic at delivery (P < 0.001). Multivariate logistic regression analysis revealed the odds of anaemia for a woman not on iron therapy was about 11 times that of her counterpart on prophylactic iron therapy (95% CI 8.76 to 14.13). A 55% reduction in odds of anaemia was estimated per 1 gm% increase in haemoglobin at booking. Prophylactic antenatal iron supplements not only prevent a fall but also improved haemoglobin levels during pregnancy. Those who were not on any iron supplements were 11 times more likely to develop anaemia in the present pregnancy.

Anemia↗
PubMed1998

Choledochal cysts in infants and children.

OBJECTIVE: To study the clinical spectrum and management of choledochal cyst in children below 12 years of age. DESIGN: Descriptive study. SETTING: Tertiary care hospital. METHODS: Twenty three children with choledochal cysts were managed between January 1991 to September 1997 and their clinical details, investigations and management were recorded. Choledochal cyst was diagnosed by ultrasonography and confirmed by ERCP or peroperative cholangioram (POC) Children were treated with antibiotics and/or percutaneous transhepatic biliary drainage if there was cholangitis and subsequently subjected to surgery (excision of the cyst and jejunal loop interposition hepaticoduodenostomy). RESULTS: The median age of these children was 3 years with an almost equal sex ratio. Predominant presentation was jaundice in 18, pain abdomen in 15, fever in 12, and lump abdomen in 9 cases. The classical triad of jaundice, pain and lump was present in only 4 cases. ERCP conducted in 7 and POC in 14 cases yielded positive findings in all. Clinically there were two distinct forms of presentation: (i) infantile form (< or = 1 year) comprised 9 infants which presented with jaundice in all, acholic stool in 6, lump abdomen in 4 but only one had classical triad; and (ii) childhood form (> 1 year) presented with pain abdomen in 12 and jaundice and cholangitis in 9 subjects each. Type I cyst was seen in 20 and type IVa in 3. Two children refused surgery, and the rest underwent surgery. Three infants died after surgery, the remaining 18 were alive and well on follow-up (median 25 months). Secondary biliary cirrhosis was seen in 6, extra hepatic biliary artresia in 2 and congenital hepatic fibrosis in 1 on histology. CONCLUSIONS: Choledochal cysts present in two clinically distinct forms. Infantile form is an important cause of cholestasis of infancy. Early diagnosis and referral is essential to prevent complications and death, and prognosis after surgery is good.

Abdominal Pain↗
PubMed1998

Silent gastroesophageal reflux in patients with bronchial asthma.

Gastroesophageal reflux (GER) is a common occurrence in patients with asthma. We performed a prospective study to detect GER in patients with asthma using pH monitoring. Twenty consecutive patients (mean age 48 +/- 14 yr, range 23-70; 13 men) with asthma of unexplained etiology were evaluated. Esophageal and gastric pH were studied both while introducing and pulling out pH probe. Upper GI endoscopy was done in all the patients before doing pH monitoring. Esophageal pH was recorded at 25 cm, 30 cm and 35 cm from the incisors. Mean esophageal pH values while introducing pH probe were 2.9 +/- 1.08 (0-5.1), 2.5 +/- 1.2 (0-5) and 1.6 +/- 1.5 (0-4.6) at 25 cm, 30 cm and 35 cm from incisors respectively. The gastric pH was 0.5 +/- 0.4 (0-2). While pulling out pH probe, pH values were 1.5 +/- 1.4 (0-4.7), 2.4 +/- 1.5 (0-5.1) and 2.9 +/- 1.4 (0-5.4) at 35 cm, 30 cm, and 25 cm from incisors respectively. Of 20 patients, 19 had pH of 4 or lower at 25 cm, 30 cm and 35 cm from incisors. The mean pH value was lower at 35 cm than at 30 cm and 25 cm (1.6 +/- 1.5 vs 2.5 +/- 1.2 and 2.9 +/- 1.08, p < 0.04). In conclusion majority of adults with asthma have silent GER as detected on pH monitoring.

Adult↗
PubMed1998

Acetylsalicylic acid-induced biochemical changes in gastric juice: a failure of adaptation?

BACKGROUND: Acetylsalicyclic acid (ASA) causes gastric mucosal damage which diminishes with continued use due to adaptation. METHODS: To determine the net effect of these processes on the gastric juice, we estimated acid, osmolality, bicarbonate concentration in nonparietal gastric juice, calcium, potassium and sodium in 18 patients (9 men; mean age 32 years, range 20-46) with irritable bowel syndrome, before and after 600 mg of ASA taken post-cibum thrice daily for 4 weeks. Osmolality was determined by an osmometer, acidity by titration, and Na+, K+ and Ca++ using a sodium-potassium-calcium analyzer; bicarbonate was derived from the two-component model of Feldman. RESULTS: Gastric juice K+ and Na+ increased significantly from mean (SE) 14.6 (0.5) and 197.5 (16.3) to 16.7 (0.4) and 256.8 (18.1) mEq/L, respectively. The other parameters remained unchanged. CONCLUSION: After four weeks of ASA ingestion there is a dichotomy of gastric mucosal injury and adaptation, with preservation of acid secretion but continued loss of Na+ and K+.

Adaptation, Physiological↗
PubMed1998

Risk of hypotony after primary trabeculectomy with antifibrotic agents in a black west African population.

PURPOSE: To evaluate the risk of hypotony and hypotony maculopathy following trabeculectomy with 5-fluorouracil (5-FU) and mitomycin C (MMC) in a black West African population. METHODS: One hundred and one eyes of black Ghanaian patients with advanced primary open-angle glaucoma received intraoperative antifibrotic therapy with trabeculectomy as part of two randomized clinical trials. Overall, 57 patients received 5-FU (50.0 mg/ml for 5 minutes) and 44 received MMC (0.5 mg/ml for 3.5 minutes). All cases were performed by one of five surgeons at a single outpatient surgery center. RESULTS: Two of 101 eyes had a final intraocular pressure (IOP) of less than 5 mm Hg and were thus classified as having hypotony. No patient in either group was noted to develop hypotony-related maculopathy. Overall mean pre- and postoperative IOPs were 30.1 and 15.9 mm Hg, respectively. The patients receiving intraoperative MMC had a lower mean postoperative IOP (14.7 mm Hg) than those receiving 5-FU (first study, 17.1 mm Hg; second study, 16.7 mm Hg; p = 0.05). Mean overall follow-up was 17.7 months and did not differ significantly between the MMC and combined 5-FU groups. CONCLUSION: Hypotony following trabeculectomy supplemented with antifibrotic agents is a rare complication in this population. No eyes in either clinical trial developed hypotony maculopathy, suggesting that the prevalence of this condition is substantially lower in black West Africans than in whites.

Fluorouracil↗
PubMed1998

Race-related stress among Asian American veterans: a model to enhance diagnosis and treatment.

This article addresses theoretical principles and clinical descriptions of the phenomenon of race-related stress and trauma experienced by Asian American Vietnam veterans. A conceptual model of race-based stress is presented, comprised of five principles, by which to understand mental health difficulties that can arise in regard to race-based stressors. The model describes (a) the relationship between life threat and physical similarity to the "enemy," (b) the relationship between fear and prejudice, (c) dehumanization as it impacts race hate and combat indoctrination, (d) additive life threat related to exploitation of one's physical similarity to the "enemy," and (e) race-based remorse. The article delineates factors affecting treatment seeking and disclosure of race-based stresses, guidelines for interviewing veterans about race-related events and ethnic self-worth, and the harmful effects of race hate.

Acculturation↗
PubMed1998

Delayed corneal epitheliopathy after antimetabolite-augmented trabeculectomy.

PURPOSE: The authors describe the first case of delayed antimetabolite-related corneal epithelial toxicity after trabeculectomy and its successful treatment with limbal stem cell transplantation. METHODS: A 73-year-old woman underwent trabeculectomy with intraoperative mitomycin C. After surgery she received six 5-mg injections of subconjunctival 5-fluorouracil (5-FU) adjacent to the bleb. RESULTS: The patient had a functioning trabeculectomy and clear cornea until 30 months after surgery, at which time she developed a nonhealing superior corneal epithelial defect. After 4 months of conservative medical management, an autologous limbal stem cell transplantation was performed. The epithelial defect resolved completely within 1 week of limbal stem cell transplantation. CONCLUSIONS: Delayed corneal epithelial toxicity may be a late complication of antimetabolite-augmented trabeculectomy.

Aged↗
PubMed1998

Picroliv prevents oxidation in serum lipoprotein lipids of Mastomys coucha infected with Plasmodium berghei.

Picroliv, an iridoid glycoside mixture from the root and rhizome of Picrorhiza kurrooa, at the dose of 6 mg/kg p.o. for two weeks provided significant protection against the generation of lipid peroxidation products in serum beta-lipoproteins of P. berghei infected M. coucha. Incubation of normal rat hepatocytes with very low density lipoprotein or low density lipoprotein isolated from infected animals caused significant generation of lipid peroxides followed by a decrease in the viability of these cells, however these effects were partially reversed with the lipoproteins from infected and picroliv treated groups. High density lipoprotein from infected animals was not toxic to hepatocytes in vitro.

Animals↗
PubMed1998

Sudden profound hypoxaemia in the intensive care unit--a case report.

Acute hypoxaemia is a life-threatening emergency. Diagnosis of the exact aetiology maybe complicated by the presence of pre-existing lung conditions. A case report is presented of a non-intubated patient with a pre-existing lung tumour who developed sudden profound hypoxaemia 3 days after emergency abdominal surgery. Definitive aetiological diagnosis was delayed due to chest X-ray features suggestive of compression and erosion of tumour tissue into the airway. Emergency computerised tomography (CT) imaging however revealed mucous plugging leading to massive atelectasis as the main aetiology.

Carcinoma↗
PubMed1998

Early failure of long segment anterior cervical plate fixation.

A retrospective, multicenter study was undertaken to evaluate the early postoperative failure rate of long segment anterior cervical fusion and plating to stabilize the cervical spine after a two- or three-level corpectomy for degenerative, traumatic, and neoplastic diseases of the cervical spine. Patient demographic factors as well as technical factors such as bone graft placement, plate and screw position, and postoperative brace immobilization were analyzed. During the early postoperative period, the graft/plate construct dislodged in 3 of 33 patients with a two-level corpectomy and fusion (9%) compared with 6 of 12 patients with a three-level corpectomy and fusion (50%). The difference in failure rates after a three- versus two-level corpectomy and fusion was statistically significant (p < 0.05). A higher early failure rate was also seen with failure to correctly lock the screws to the plate and the use of a peg-in-hole type bone grafting technique, although these differences were not statistically significant. Although several technical and patient-specific factors may contribute to this, anterior cervical plating and bone grafting alone after a three-level cervical corpectomy for various spinal disorders appears to afford inadequate stability in the early postoperative period, regardless of immobilization methods.

Adolescent↗
PubMed1998

Absence of Helicobacter pylori in oral mucosal lesions.

A prospective study was conducted in 26 patients with benign oral ulcers and oral carcinoma and 26 age and sex matched controls to determine the prevalence of Helicobacter pylori in oral mucosal biopsies. Oral mucosal biopsies were subjected to rapid urease test, campylobacter like organism (CLO) test, histopathological examination and bacteriological culture for demonstration of H pylori. Urease test was positive for H pylori in 3 (11.4%) out of 26 cases and CLO test in 2 (14%) out of 14 cases. On histology, H pylori was identified in 4 (15.38%) out of 26 cases. The spiral organism was universally absent in culture of both patients and controls. These pilot data negate the casual association of H pylori in oral mucosal lesions.

Biopsy, Needle↗
PubMed1997

Identification and developmental characterization of a novel Y-box protein from Drosophila melanogaster.

The Y-box proteins are a family of highly conserved nucleic acid binding proteins which are conserved from bacteria to human. In this report we have identified a new member of this family from Drosophila melanogaster. Degenerate-PCR was used to identify a conserved region within the highly conserved cold-shock domain (CSD) of Y-box proteins. Subsequently, the cDNA for this gene was sequenced, and the identified open reading frame was named ypsilon schachtel (yps). The expression pattern of yps indicates that this gene is expressed throughout development with the highest level of expression found in adult flies. In situ hybridization shows that the yps mRNA is maternally loaded into the egg cytoplasm. In addition, there appears to be expression of yps mRNA in mesodermal tissue during embryogenesis. YPS, while containing a conserved CSD, is novel in that it completely lacks the alternating acidic and basic regions found in the C-terminus of the other vertebrate eukaryotic Y-box proteins. The CSD of yps was purified and gel-shift analysis showed that this domain can interact with RNA. We predict that YPS would be an RNA-binding protein due to these results and the motifs which have been identified within the amino acid sequence.

Amino Acid Sequence↗
PubMed1997

Coordination geometries for monovalent and divalent metal ions in [His121]azurin--studies using perturbed angular correlations of gamma-rays from 111Ag and 111mCd.

The structural details of the metal site in the [His121]azurin mutant from Alcaligenes denitrificans where the axial methionine has been replaced by a histidine have been studied after substitution with the divalent cadmium ion and the monovalent silver ion. The studies have been carried out in solution using the technique of perturbed angular correlations of gamma-rays (PAC) of the two isotopes, 111Ag and 111mCd. In the pH range 6-9, the PAC spectra for cadmium-substituted [His121]azurin reveals a pH-independent equilibrium between two different metal-coordination geometries. Interpretation of the PAC data shows agreement between the dominating coordination geometry and that derived from X-ray diffraction on the Cu(II)[His121] azurin at high pH (Messerschmidt, A., unpublished results). Thus, it appears likely that cadmium for this geometry is four coordinated to the ligands His46, His117, Cys112, and His121. The other geometry is best interpreted as a substitution of His121 by a solvent water ligand. These interpretations stem from predictions of the experimentally determined nuclear quadrupole interactions (NQI) via the simple angular overlap model (AOM). At low pH (3.8), the concentration of the former species is reduced to 50% of its high pH value suggesting a pK of about 4 for His121. Two different coordination geometries have also been observed for the Cu(II) protein and assigned a type 1.5 and a type 1 copper site [Kroes, S. J., Hoitink, C. W. G., Andrew, C. R., Ai, J., Sanders-Loehr, J., Messerschmidt, A., Hagen, W. R. & Canters, G. W. (1996a) Eur. J. Biochem. 240, 342-351]. For silver-substituted [His121]azurin, several notable changes occur relative to the cadmium-substituted protein. At least four different metal-coordination geometries exist for silver[His121]azurin in the pH range 4-8. Changes in the population of these coordination sites occurs between pH 4 and pH 5, and pH 5 and pH 6. Furthermore, in contrast to the cadmium-substituted protein, only a single coordination geometry is present above pH 6. The change in population occurring between pH 5 and pH 6 suggests ionization of a non-coordinating histidine, here proposed as His121. The change in population at low pH could then be due to protonation of an additional coordinating histidine such as His46 or His117. The single coordination geometry existing at pH values above 6 for the silver protein cannot within our model calculations be described with His121 coordinated. However, it can be described with a coordinated water molecule but in a different angular position than for His121 in the copper protein (Messerschmidt, A., unpublished results). The reduced tendency for silver to coordinate His121 is in agreement with the general trend of lower pK values for ligands coordinating to monovalent ions relative to divalent ions. In conclusion, this work demonstrates that mutation of Met121 to other amino acid residues opens the possibility of other coordination geometries than the rigid three-coordinated structure observed for wild-type azurin, especially the possibility of increasing the coordination number by either solvent water ligands or the substituting amino acid. Furthermore, it opens up the possibility for different coordination geometries for monovalent and divalent metal ions as observed here and previously for the [Leu121]azurin mutant [Bauer, R., Danielsen, E., Hemmingsen, L., Bjerrum, M. J., Hansson, O. & Singh, K. (1997) J. Am. Chem. Soc. 119, 157-163].

Azurin↗
PubMed1997

Trabeculectomy with intraoperative 5-fluorouracil vs mitomycin C.

PURPOSE: To compare the effectiveness of intraoperative 5-fluorouracil (5-FU) and mitomycin C used adjunctively with trabeculectomy in a black West African population. METHODS: Eighty-five consecutive eyes of 85 black patients undergoing primary trabeculectomy for open-angle glaucoma were prospectively randomly assigned to receive either 5-FU (50 mg/ml for 5 minutes) or mitomycin C (0.5 mg/ml for 3 1/2 minutes) intraoperatively by soaked sponge. RESULTS: Of the 81 eyes with at least a 3-month postoperative follow-up, 41 of 44 (93.2%) in the mitomycin C group and 27 of 37 (73.0%) in the 5-FU group had a final intraocular pressure of less than 21 mm Hg (P = .01). Twenty-eight of 44 eyes (63.6%) in the mitomycin C group and 18 of 37 (51.4%) in the 5-FU group had a final intraocular pressure of less than 15 mm Hg (P = .26). Mean postoperative intraocular pressure was 13.7 mm Hg in the mitomycin C group and 16.3 mm Hg in the 5-FU group (P = .05). There were no differences between the two groups in mean age, preoperative intraocular pressure, postoperative visual acuity, and complications. Mean follow-up was 10.0 +/- 4.41 months (range, 4 to 19 months). CONCLUSIONS: The adjunctive use of mitomycin C with trabeculectomy is equally safe and more efficacious compared to 5-FU in this West African population. Use of mitomycin C in this study was not associated with a statistically significantly greater proportion of patients achieving low intraocular pressure (less than 15 mm Hg) compared to 5-FU.

Antimetabolites↗