Search PubMed⌕ Search

Biomedical subjects

D Singh

Publications and source records attributed to D Singh.

At least 181 records · Page 10Linked to original sources
PubMed1996

Nitrous oxide exposure on the labour ward.

Occupational exposure to nitrous oxide may be increased in confined working environments where ventilation and scavenging are either ineffective or unavailable. This is particularly the case on the labour ward. To assess the exposure of midwives working on the labour ward, midwives were asked to wear personal nitrous oxide samplers during their shift periods. The nitrous oxide exposure during a total of 242 midwife shift periods was monitored in two hospitals. Seven (3%) of these midwife shifts demonstrated mean exposure levels of over 500 parts per million (ppm), the highest reaching 1638 ppm. Fifty-six (23%) had NZO levels over 100 ppm and 129 (53%) had levels above 25 ppm. During the 111 midwife shift periods where midwives did not work in a room where Entonox was in use, their mean exposure was 22 ppm (median 12 ppm), however in four of these midwife shift periods the mean exposure level exceeded 100 ppm. Chronic exposure to high levels of nitrous oxide which exceed the recently proposed UK standard of 100 ppm and those in force in the USA (25 ppm) and Sweden (100 ppm) are frequently encountered by midwives.

Journal Article↗
PubMed1996

Anaesthetic management of labour in two patients with Klippel-Feil syndrome.

Two patients with Type I Klippel-Feil syndrome presented at the antenatal clinic. The first patient, who suffered from sleep apnoea, was delivered of a healthy infant by vacuum extraction. The second, who was profoundly deaf and had marked kyphoscoliosis, developed pregnancy-induced hypertension and urinary tract infection and was delivered at 38 weeks by vacuum extraction. In both cases epidural analgesia was employed to allow pain relief during labour. Anaesthetic management of Klippel-Feil syndrome is discussed and the benefits of early anaesthetic assessment and continued involvement of senior anaesthetic and obstetric staff emphasized.

Journal Article↗
PubMed1996

Partial Achilles tendon ruptures associated with fluoroquinolone antibiotics: a case report and literature review.

Fluoroquinolone antibiotics (such as olprofloxacin, pefloxacin, ofloxacin, norfloxacin, temafloxacin, etc.) have recently been implicated in the etiology of Achilles tendinitis and subsequent tendon rupture. We report on a patient with bilateral partial Achilles tendon ruptures associated with ciprofloxacin therapy and present a review of the current literature on this increasingly recognized complication. Treatment with fluoroquinolones should be discontinued at the first sign of tendon inflammation so as to reduce the risk of subsequent rupture. Magnetic resonance imaging is useful in distinguishing between Achilles tendinitis and partial tendon rupture.

Achilles Tendon↗
PubMed1996

Aluminum phosphide ingestion--a clinico-pathologic study.

BACKGROUND: Aluminum phosphide is widely used in India as a fumigant to protect stored grain from pests and rodents. It is marketed in India as 3 g tablets under several brand names as Celphos, Phostek, Quickphos, and Phosphume. If ingested, it is acutely toxic with a high mortality. The present study was undertaken to define any factors which could predict the outcome after an ingestion. METHODS: Between March 1989 and March 1994, 195 patients with aluminum phosphide ingestion were admitted to Nehru Hospital of the Postgraduate Institute of Medical Education and Research, Chandigarh in Northwest India. The information regarding demography, time elapsed between ingestion and arrival in the hospital, nature of ingestion, dose ingested, symptoms and signs at admission and course during hospital stay was recorded on a proforma. RESULTS: Of 195 patients, 115 died. The deaths could be related to the dose ingested but not to the time elapsed between ingestion and arrival at the hospital. The nonsurvivors had more severe hypotension and metabolic acidosis than the survivors who had more severe vomiting. Autopsies conducted in 115 subjects revealed congestion of liver, spleen, kidneys, adrenals, gastrointestinal tract and brain that correlated with the severity of hypotension. Histopathology did not reveal any specific changes beyond visceral congestion and patchy necrosis of the liver. CONCLUSION: Aluminum phosphide when ingested is highly toxic with fatal dose as low as 1.5 g. The dominant clinical feature is severe hypotension refractory to dopamine.

Adolescent↗
PubMed1996

Glutathione-S-transferase in rat ovary: its changes during estrous cycle and increase in its activity by estradiol-17 beta.

Glutathione-S-transferases (GSTs) are drug metabolizing and detoxification enzymes, involved in the intracellular transport and metabolism of steroid hormones. This study indicated that the enzyme was heterogeneously distributed and changed during estrous cycle. The enzyme was found to be predominantly located in the cytosolic fraction while considerable activity was also observed in the mitochondrial and microsomal fractions. The activity of GST was measured during different stages of estrous cycle, viz proestrous, estrous, metestrous and diestrous. The change in its activity was observed during different stages of estrous cycle. Estrous stage was observed to have the highest GST activity. Immature (28-29 days old) rats treated with estradiol-17 beta (5 micrograms in 0.2 ml oil/animal/day, and 10 micrograms in 0.2 ml oil/animal/day, for 3 days), ovarian GST activity seemed to increase significantly (P < 0.01). This increase in the activity and the heterogeneous distribution of GST indicates the functional role of this enzyme in the ovary under endocrine regulation.

Animals↗
PubMed1995

The carboxyl-terminal region of the Na+/H+ exchanger interacts with mammalian heat shock protein.

We expressed the carboxyl-terminal 178 amino acids of the rabbit cardiac Na+/H+ exchanger as a fusion protein with glutathione-S-transferase. The fusion protein (PCR178) was found in the supernatant of extracts of E. coli and was purified using Glutathione-Sepharose affinity chromatography. Affinity-purified antibodies raised against the carboxyl-terminal region of the Na+/H+ exchanger identified the resultant protein. PCR178 copurified with a 70 kDa protein. Amino-terminal sequencing of the 70 kDa protein identified it as dnaK, the bacterial equivalent of the mammalian 70 kDa heat shock protein (hsp70). DnaK was dissociated from the Na+/H+ exchanger fusion protein by the addition of MgATP. When purified PCR178 was coupled to a cyanogen bromide-activated Sepharose column, bovine hsp70 bound to the column and was eluted with MgATP. Nondenaturing polyacrylamide gel electrophoresis showed that, in the absence of MgATP, hsp70 formed a complex with PCR178. The complex was dissociated by the addition of MgATP. GST alone did not form a complex with hsp70. Immunoprecipitation of the Na+/H+ exchanger with antiexchanger antibodies resulted in coprecipitation of hsp70 protein from antiporter containing cells. Cells that overexpress the Na+/H+ exchanger had increased amounts of hsp70 which coprecipitated with antiexchanger antibody. The results show that heat shock protein complexes with the mammalian Na+/H+ exchanger.

Amino Acid Sequence↗
PubMed1995

Glycosphingolipid acyl chain order profiles: substituent effects.

Fatty acid order parameter profiles were determined by 2H-NMR in order to characterize the arrangement and behaviour of the hydrophobic region of glycosphingolipids (GSLs) dispersed as minor components in phosphatidylcholine/cholesterol membranes. Direct comparison was made amongst species with important fatty acid structural features found in natural glycosphingolipids. Galactosyl ceramides (GalCer) were prepared by partial synthesis having 18:0[d35], D-alpha-OH 18:0[d34], 18:1[d33], and 24:0[d47] fatty acids. Unsonicated multilamellar liposomes of the common natural phospholipid, 1-palmitoyl-2-oleoylphosphatidylcholine (POPC), containing 23% cholesterol, were employed as host matrix. Smoothed profiles of the order parameter, SCD, for 18:0[d35] GalCer proved to be very similar to profiles known for 16:0 and 18:0 fatty acids of glycerolipids in cholesterol-containing bilayers. In general, order along the GSL chain was slightly higher than anticipated for equivalent chain segments in phospholipids. Order parameter profiles for the GSL 18-carbon saturated fatty acids were strikingly similar. However, small quantitative differences were found for glycolipids having D- and L-alpha-hydroxylation at C-2 - the D-stereoisomer being marginally more ordered in the plateau region. Although order profiles have not been reported for unsaturated glycerolipid fatty acids in cholesterol-rich membranes, spectra of 18:1[d33] GalCer appeared to be assignable by applying known ordering effects of cholesterol to existing data for unsaturated glycerolipids. The unsaturated chain was found to be less ordered than saturated 18-carbon chains toward the membrane surface, but more ordered in the region of the bilayer midplane. The ordering may result from cholesterol-induced restriction of isomerisation at the cis-double bond, and represents an apparent exaggeration of a phenomenon known for glycerolipids. Addition of an 'extra' 6 carbons to the fatty acid (24:0[d47] GalCer) produced no significant effect on the order profile to a membrane depth of C-12-C-13. These results suggest that fluid membrane area requirements for GSLs with saturated fatty acids are not strongly influenced by the nature of that fatty acid when the GSL is a minor component. Order parameter profiles for the very long chain GSL deviated to higher order below this point, and formed a second 'plateau' of reduced negative slope toward the methyl terminus: this is characteristic of profiles for very long chain GSLs. These features were essentially unchanged over a range of temperatures providing different degrees of spatial constraint.

Animals↗
PubMed1995

Simultaneous raw starch hydrolysis and ethanol fermentation by glucoamylase from Rhizoctonia solani and Saccharomyces cerevisiae.

Crude glucoamylase preparation from Rhizoctonia solani was used to saccharify raw and cooked starch. Various concentrations of potato starch and wheat flour from 10-40%, w/v were used for mashing but 30% was found to be the optimal and economical. The saccharified mash yielded 5.89%, v/v ethanol in a simultaneous saccharification and fermentation process using a yeast strain Saccharomyces cerevisiae (SC-39) at 35 degrees C for 4 days. Removal of inhibitory substances from the fermenting broth through dialysis caused considerable increase in ethanol production.

Ethanol↗
PubMed1995

Biological treatment of distillery waste for pollution-remediation.

The biological treatment of spent wash from molasses distilleries was investigated. Analysis of raw spent wash showed it to be a recalcitrant waste, with a high COD of 85,170 mg/l and containing inhibitory phenolic compounds. Reverse phase thin layer chromatography identified gallic and vanillic acid present in spent wash. The fungi Geotrichum candidum, Coriolus versicolor, Phanerochaete chrysosporium and Mycelia sterilia were screened for their ability to decolourize spent wash and to reduce the COD level. A 10 day pretreatment with Geotrichum candidum at 30 degrees C resulted in reducing the COD by 53.17% and total phenols by 47.82%, enabling other bioremediating organisms to grow. Coriolus versicolor immobilized in a packed-bed reactor reduced the COD of spent wash by a further 50.3%, giving an overall reduction in COD of 77% to 15,780 mg/l. A small amount of decolourization was achieved (4.2%), although the spent wash was still coloured. Present studies are encouraging and indicate that it is possible to bioremediate spent wash using a multi-stage treatment process involving an initial pretreatment step with Geotrichum candidum.

Bacteria↗
PubMed1995

Xanthomonas campestris pv. parthenii pathovar nov. incitant of leaf blight of parthenium.

A new bacterial leaf blight disease of parthenium (Parthenium hysterophorus L.) is described for the first time. The disease-causing bacterium was isolated and its morphological, physiological and biochemical characters were determined. The pathogenicity of bacterium is apparently limited only to parthenium. The pathogen was identified as Xanthomonas campestris pv. parthenii pathovar nov. on the basis of morphological, physiological, biochemical and pathogenic characteristics.

Energy Metabolism↗
PubMed1995

Glycosphingolipid fatty acid arrangement in phospholipid bilayers: cholesterol effects.

Deuterium wide line NMR spectroscopy was used to study cholesterol effects on the ceramide portions of two glycosphingolipids (GSLs) distributed as minor components in fluid membranes. The common existence of very long fatty acids on GSLs was taken into account by including one glycolipid species with fatty acid chain length matching that of the host matrix, and one longer by 6 carbons. N-stearoyl and N-lignoceroyl galactosyl ceramide with perdeuterated fatty acid (18:0[d35] GalCer and 24:0[d47] GalCer) were prepared by partial synthesis. They were dispersed in bilayer membranes having the 18-carbon-fatty-acid phospholipid, 1-stearoyl-2-oleoyl-phosphatidylcholine (SOPC), as major component. Glycolipid fatty acid chain behavior and arrangement were analyzed using order profiles derived from their 2H-NMR spectra. Cholesterol effects on order parameter profiles for 18:0[d35] GalCer, with chain length equal to that of the host matrix, followed the pattern known for acyl chains of phospholipids. The presence of sterol led to restriction of trans/gauche isomerization along the length of the chain, with the largest absolute increase in order parameters being toward the surface, but somewhat greater relative effect just below the "plateau" region. In cholesterol-containing membranes, order parameter profiles for the long chain species, 24:0[d47] GalCer, showed a characteristic secondary "plateau" associated with carbon atoms C14 to C23, a feature also present in SOPC bilayers without cholesterol and in pure hydrated 24:0[d47] GalCer. Cholesterol-induced ordering effects on the long chain glycolipid were similar to those described for the shorter chain species, but were minimal at the methyl terminus. Within a given membrane,SCD profiles for 1 8:O[d3] GalCer and 24:0[d47] GalCer were quantitatively similar to a membrane depth of C13 to C14. SCD values at C16 and C17 were about 15% and 28% higher, respectively, for the long chain GSL than for its short chain analogue inSOPC/cholesterol (compared to 21 and 31%, respectively, in membranes without cholesterol). Nitroxide spin labels attached rigidly to C16 of the long chain glycolipid gave EPR order parameters that were twice as high as for the same spin label at C16 on the shorter chain glycolipid in both matrices. It would appear that the above factors impose a tendency for the "extra" portion of the 24-carbon chain to cross the bilayer midplane where it may interact with terminal portions of acyl chains in the opposing monolayer; however, steric constraints, and probably collision events associated with lateral diffusion, induce wide orientation fluctuations in the segment involved.

Animals↗