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Biomedical subjects

A Singh

Publications and source records attributed to A Singh.

At least 19 recordsLinked to original sources
PubMed1992

Analgesia for the reduction of Colles fracture. A comparison of hematoma block and intravenous sedation.

OBJECTIVE: An alternative to general anesthesia was tested against conventional sedation by a double-blind, randomized clinical trial in reduction of Colles fracture. SETTINGS: A large teaching hospital where cases of Colles fracture are not different from those seen in district hospitals. PATIENTS: Sixty-six out of 80 consecutive cases with this fracture were selected from March to August 1990 on the basis of: 1) informed consent; 2) no contraindication to any method of analgesia; 3) no analgesic during the past 8 hours; 4) injury duration less than 96 hours; 5) no mental, auditory, or visual impairment; and 6) no associated injury. INTERVENTIONS: Patients were randomized into 2 equal groups. After tests for Xylocaine (Astra brand of lidocaine hydrochloride) sensitivity in both groups, the A group received 30 mg of pentazocine with 5 mg of diazepam intravenously on the dorsum of the affected wrist (sedation group), whereas the B group received 20 cc of 1.5% Xylocaine into the fracture hematoma. Five minutes later the fracture was reduced and immobilized by Lakhtakia or A. Singh. MAIN OUTCOME MEASURES: Thirteen to 15 hours later Manglik, blinded to the analgesia status of the patient, recorded pain before, during, and after reduction using Visual Analogue Scale (VAS). MAIN RESULTS: Statistically, randomization and blinding were found to be effective. The pain scores during reduction in the local anesthetic group (median = 1.8) were significantly less than those in the sedation group (median = 8.7), P < 0.001 using the Wilcoxon rank sum test. The difference persisted in regression analysis. The 2 methods proved comparable in safety and other measures of effectiveness. CONCLUSIONS: Hematoma block by local anesthetic is a safe and effective alternative to sedation in reduction of Colles fracture.

Adult↗
PubMed1992

Purification of cationic cystine-rich peptides from rat bone marrow. Primary structures and biological activity of the rat corticostatin family of peptides.

Seven cationic, cystine-rich peptides of 29 to 32 amino acid residues have been purified from extracts of rat bone marrow (R-1, R-1a, R-1b, R-2, R-3, R-4 and R-5). Structural analysis clearly indicated that all seven peptides belong to the corticostatin/defensin family of leukocyte-derived peptides known to participate in oxygen-independent killing of phagocytosed bacteria. For R-1 to R-5, six cysteine residues were found at characteristic and highly conserved positions. R-1a and R-1b were partially characterized and appear to be structural variants of R-1. Aside from the conserved cysteines, there is a remarkable degree of structural diversity evident within the sequences of those members of the corticostatin/defensin family characterized so far. The structures of the peptides that we have purified can be compared directly with the sequences obtained for rat defensins isolated from extracts of peritoneal neutrophils (Lehrer, Ganz and Selsted, Cell, 64 (1991) 229-230). Some discrepancies are apparent which can be explained in terms of proteolytic cleavage of several of these peptides at both amino- and carboxyl-termini. The corticostatins owe their bioactivity to their ability to compete with corticotropin for occupancy of the corticotropin receptor (Zhu, Hu, Mulay, Esch, Shimasaki and Solomon, Proc. Natl. Acad. Sci. USA, 85 (1988) 592-596). The potency of these peptides can be expressed in terms of their capacity to inhibit the steroidogenic response of isolated rat adrenocrotical cells half-maximally stimulated by corticotropin (i.e., at the ED50 concentration for corticotropin in this assay, namely 33 pM). In this assay, the rat peptides R-1, R-2 and R-3 were shown to be inactive. In contrast, the more cationic peptides R-4 and R-5 were found to inhibit steroidogenesis. R-4 was somewhat less active than rabbit corticostatin (IC50 25 nM) showing an IC50 value of 50 nM. R-5 appeared to be significantly less potent than R-4. The lower yield of R-5 precluded an accurate estimate of the corticostatic potency of this peptide. R-4 differs in structure from R-5 in having an arginine to serine substitution at position 7. It can be concluded that an arginine at this position accounts, at least in part, for the corticostatic activity of R-4.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenocorticotropic Hormone↗
PubMed1992

Lipid accumulation by a cellulolytic strain of Aspergillus niger.

Lipid accumulation by a cellulolytic mold, Aspergillus niger, was studied. The amount of lipid accumulated ranged from 13.6-16.6% on various carbon sources, namely glucose, xylose, avicel (microcrystalline cellulose) and bagasse (a natural lignocellulosic substrate). Neutral lipids, phospholipids and glycolipids of the mycelia varied from 41.0-46.2%, 34.9-38.4% and 18.7-22.6% of total lipids, respectively. Unsaturated fatty acids comprised around 80% of total fatty materials with linoleic and oleic acid predominating. Of the four nitrogen sources tested, NH4Cl was the best source for lipid synthesis from cellulose (bagasse). Optimum temperature range for growth and lipid synthesis was 25-30 degrees C.

Aspergillus niger↗
PubMed1992

The familial occurrence of Parkinson's disease. Lack of evidence for maternal inheritance.

A questionnaire concerning the occurrence of Parkinson's disease in parents was administered for 252 patients with Parkinson's disease. Eleven fathers and five mothers of patients were reported to also have had this disease. These data fail to provide support for the hypothesis that Parkinson's disease is the result of maternal inheritance of an abnormal mitochondrial gene. This conclusion is further supported by a review of similar studies in the literature and an additional unpublished study, which revealed that of 922 patients with this disease, 37 fathers and 19 mothers were reportedly affected.

Aged↗
PubMed1992

Lack of major olfactory dysfunction in MPTP-induced parkinsonism.

The olfactory function of 6 patients whose parkinsonism was the result of intravenous administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was compared to that of 12 age-matched patients with idiopathic Parkinson's disease (PD) and 10 age-matched normal control subjects. Unlike their PD counterparts, the olfactory test scores of patients with MPTP-induced parkinsonism did not differ significantly from those of control subjects. These findings suggest that MPTP-induced parkinsonism, unlike idiopathic PD, is unaccompanied, on average, by major alterations in the ability to smell.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1992

RNase X2, a pistil-specific ribonuclease from Petunia inflata, shares sequence similarity with solanaceous S proteins.

Petunia inflata, a species with gametophytic self-incompatibility, has previously been found to contain a large number of ribonucleases in the pistil. The best characterized of the pistil ribonucleases are the products of the S alleles, the S proteins, which are thought to be involved in self-incompatibility interactions. Here we report the characterization of a gene encoding another pistil ribonuclease of P. inflata, RNase X2. Degenerate oligonucleotides, synthesized based on the amino-terminal sequence of RNase X2, were used as probes to isolate cDNA clones, one of which was in turn used as a probe to isolate genomic clones containing the gene for RNase X2, rnx2. The deduced amino acid sequence of RNase X2 shows 42% to 71% identity to the 20 solanaceous S proteins reported so far, with the highest degree of similarity being to S3 and S6 proteins of Nicotiana alata. The cDNA sequence predicts a leader peptide of 22 amino acids, suggesting that RNase X2, like S proteins, is an extracellular ribonuclease. Also, similar to the S gene, rnx2 is expressed only in the pistil, and contains a single intron comparable in size and identical in location to that of the S gene. However, rnx2 is not linked to the S locus, and, in contrast to the highly polymorphic S gene, it is monomorphic. The possible biological function of RNase X2 is discussed.

Amino Acid Sequence↗
PubMed1992

Treatment of glaucoma following penetrating keratoplasty with transscleral YAG cyclophotocoagulation.

Thirteen patients with refractory glaucoma following penetrating keratoplasty were treated with 180 degree transscleral Neodymium: YAG cyclophotocoagulation. Intraocular pressures below 21 mmHg were achieved in nine patients (69%) with a mean follow up of 19.8 months. Multiple treatments were required in six patients and graft decompensation occurred in five. No patient developed hypotony. Transscleral YAG cyclophotocoagulation is a useful alternative to further surgery in some patients with glaucoma following penetrating keratoplasty.

Adult↗
PubMed1992

Modulation of bilayer structures derived from diacetylenic phosphocholines containing oxygen linker beta to diacetylene.

Phospholipids with diacetylenes present in the acyl chains form tubules and helices in aqueous dispersions. In order to modulate the morphology of bilayer structures and to understand the role of diacetylene in lipid-bilayer assembly, two diacetylenic phosphocholines, 1,2-bis(9,16-dioxa-hexacosa-11,13-diynoyl)-sn-3-phosph ocholine and 1,2-bis(15-oxa-pentacosa-10,12-diynoyl)-sn-3-phosphocholine, in which the diacetylene is linked to the acyl chain by an oxygen spacer have been synthesized. Lipid dispersions were characterized by calorimetric, film balance and microscopic techniques. Placement of oxygen spacer influences the morphology of the bilayer assemblies formed in aqueous solution. When both ends of the diacetylene were linked to the acyl chain by oxygen atoms, liposomes (diameters ranging from 0.3-3.4 microns) were observed by optical microscopy. Linking only the terminal portion of the acyl chain to the diacetylene with an oxygen atom resulted in a lipid which formed tubular microstructures as well as vesicles. Diameter of the tubular structures ranged from 0.4-4.7 microns. Transmission electron microscopic (TEM) analysis of replicas of a freeze fractured sample of the dispersion revealed that the tubular structures were hollow cylinders consisting of an aqueous core surrounded by a wall of lipid.

Alkynes↗
PubMed1992

What is the validity of an "abnormal" evoked or event-related potential in MS? Auditory and visual evoked and event-related potentials in multiple sclerosis patients and normal subjects.

The predictive validity of evoked potentials (EPs) and event-related potentials (ERPs) in multiple sclerosis (MS) has not yet been fully investigated, as only the sensitivity of these tests has sofar been reported. EPs (short, middle and long latency auditory evoked potentials and visual evoked potentials) and ERPs (visual and auditory) were studied in 19 controls and 30 multiple sclerosis (MS) patients. Abnormality thresholds of peak latencies were defined on the basis of the mean plus 2 or 3 standard deviations, based on data from the control group. The effects of changing the latency thresholds and including the absence of peaks in the abnormality definition were assessed. In accordance with earlier reports we found a high sensitivity (up to 93% for bimodal combined EPs and 47% for combined ERPs). False positive rates of separate peaks were low and conformed to expectation. However, combining separate peak measurements increased false positive rates of EPs and ERPs to unacceptably high levels (up to 58% for combined EPs and 32% for combined ERPs). Positive likelihood ratios for bimodal EPs were low (between 1.6 and 4.0, depending on the abnormality definition). They ranged from 1.4 to 2.2 for bimodal ERPs. Abnormal combined EPs or ERPs were therefore not the reliable indicators of functional damage that they are supposed to be. Separate EPs were much more reliable in this respect. ERPs failed to distinguish between the groups, either separately or in combination. Changing the latency threshold and including absent peaks in the abnormality definition influenced the abnormality rates in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Quantitative regional variation in the expression of major histocompatibility class II antigens in enterocytes of the mouse small intestine.

The qualitative and quantitative expression of major histocompatibility class II antigens was investigated in the absorptive epithelium of the duodenum, jejunum, and ileum from mice of C3H/He (H-2k haplotype) and C57BL/6 (H-2b haplotype) strains by peroxidase-antiperoxidase labelling and image analysis. Immunohistochemical labelling revealed that the expression of class II antigens was greatest in the ileum and decreased proximally towards the duodenum. The villus epithelium of the duodenum showed a granular staining pattern in the apices of some cells. In the jejunum, an increased expression was demonstrated in the apical and basal cytoplasm of all cells covering the villus. Cells at the tip of the villus, in addition, showed staining of the lateral surfaces. Ileal enterocytes demonstrated the most intense immunostaining appearing in the cytoplasm and along baso-lateral surface membranes. Quantitative analyses confirmed that a highly significant (p less than 0.0001) difference in expression of class II antigens occurred in the three regions of the small intestine, which corroborated the qualitative findings. This regional variation of class II molecules by the absorptive epithelium may influence regional differences in antigen presenting functions and immune responsiveness to ingested antigens.

Animals↗
PubMed1992

Identification of albumin in breast tumor cytosol as a factor involved in the stimulation of estradiol 17 beta-hydroxysteroid dehydrogenase (reductive) activity.

Estradiol 17 beta-hydroxysteroid dehydrogenase (E2DH) is the enzyme responsible for the interconversion of estrone (E1), and the more biologically potent steroid, estradiol (E2), and has a crucial role in regulating breast tissue concentrations of E2. It has previously been shown that breast tumor cytosol is able to preferentially stimulate the reductive conversion of E1 to E2 in cultured MCF-7 breast cancer cells. In this study the stimulatory factor(s) from breast tumor cytosol have been partially purified by gel filtration and affinity chromatography. Human serum albumin (HSA) has been identified as a component of this bioactive fraction. Subsequent testing of commercially purified HSA preparations has revealed the ability of some preparations to be highly stimulatory. The albumin present in breast tumor cytosol may therefore be a contributing factor to the observed stimulation of reductive E2DH activity in cultured MCF-7 cells. Such a mechanism may account in part for the higher concentrations of E2 which are observed in breast tumors in vivo.

Breast Neoplasms↗
PubMed1992

Synergistic interaction of growth factors and albumin in regulating estradiol synthesis in breast cancer cells.

Estradiol 17 beta-hydroxysteroid dehydrogenase acts to convert estrone to the biologically active estrogen, estradiol, in breast tumors and MCF-7 breast cancer cells in vitro. In this study we have examined the ability of albumin to influence the effect of growth factors (insulin-like growth factor-I (IGF-I), epidermal growth factor (EGF), transforming growth factor-alpha (TGF alpha)) and cytokines (interleukin (IL)-1, IL-6) on estradiol 17 beta-hydroxysteroid dehydrogenase activity in MCF-7 cells. IGF-I (80 ng/ml) or albumin (30 micrograms/ml) stimulated estradiol 17 beta-hydroxysteroid dehydrogenase activity by 144% and 102% (p less than 0.01). The combination of IGF-I and albumin, however, produced a marked (704%) synergistic stimulation of estradiol 17 beta-hydroxysteroid dehydrogenase activity. EGF or TGF alpha failed to stimulate estradiol 17 beta-hydroxysteroid dehydrogenase activity and no synergism with albumin was detected. IL-1 (10 ng/ml), but not IL-6, also stimulated estradiol 17 beta-hydroxysteroid dehydrogenase activity and acted synergistically with albumin to stimulate enzyme activity. MCF-7 cells were shown to specifically bind 125I-albumin and binding is increased by pretreatment of cells with IGF-I (80 ng/ml) for 48 h. It is concluded that the synergism that results from treating MCF-7 cells with albumin and IGF-I may result from increased albumin uptake and subsequent biological effect.

Albumins↗
PubMed1992

Vitamin and mineral status in physically active men: effects of a high-potency supplement.

Changes in nutritional status during supplementation with a high-potency multivitamin-mineral supplement were examined in 22 physically active men randomly assigned to take a supplement (n = 11) or placebo (n = 11) for approximately 12 wk. Four-day dietary intakes, blood concentrations, and urinary excretions of selected vitamins and minerals were measured before, during (approximately 6 and 12 wk), and after supplementation. No changes were observed in blood concentrations of vitamins A and C and measures of zinc, magnesium, and calcium status; the supplement provided less than 300% of the recommended dietary allowance (RDA) of these nutrients. In contrast, blood concentrations of thiamin, riboflavin, vitamins B-6 and B-12, pantothenate, and biotin increased significantly (P less than 0.05) by 6 wk to values that were maintained until the end of the supplementation. These vitamins were provided in amounts that ranged from 396% (biotin) to 6250% (vitamin B-6) of the RDA. Urinary excretions of these vitamins also increased during supplementation and both blood and urine values returned to presupplementation concentrations at approximately 13.5 wk postsupplementation.

Adult↗
PubMed1992

Endoscopic visualisation of the human nasolacrimal system: an experimental study.

Orthograde and retrograde endoscopy of the upper and lower nasolacrimal system was performed using two prototype ultrathin (0.5 mm and 1.1 mm diameter) fibrescopes on four cadaver heads. Appearances were verified by subsequent dissection. The procedure, which we term 'dacryocystoscopy' is described. With modifications this technique may have clinical applications in the treatment of nasolacrimal disorders.

Cadaver↗
PubMed1992

Repair of anterior secondary palate fistula using tongue flaps.

Seventy-two cases of palatal fistulae are presented. The location on anterior part of secondary palate is due to lack of double layer closure. Vascular pattern of tongue is detailed. Operative details of using tongue flap as oral layer in closure of fistula are described. Undue mobility of tongue and prevention of breakdown of tongue flap repair incidence of which is low in present series are mentioned. It is suggested as excellent method of closure of palatal fistulae in difficult cases.

Child↗