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Biomedical subjects

A Sharma

Publications and source records attributed to A Sharma.

At least 991 records · Page 55Linked to original sources
PubMedDate not supplied

Study of congenital duodenal obstruction.

A study of 23 neonates with congenital duodenal obstruction is reported. Their mean gestational age was 38 weeks and mean weight was 2.2 kg. Main clinical features observed were vomiting (100%), which was bilious in 74%, and epigastric fullness with visible peristalsis (74%). Plain X-ray abdomen confirmed the diagnosis in 78%. Associated congenital malformations were seen in 39% of cases. Eleven babies had an intrinsic defect, 11 had extrinsic defect and one baby had combination of intrinsic and extrinsic defect. Malrotations along with band was seen in 39% of cases. Reported mortality was 39%.

Amniotic Band Syndrome↗
PubMedDate not supplied

Foreign body airway in neonates.

Two cases of foreign body in neonates less than one month of age are reported. Although foreign bodies in neonates are unknown but the possibility should not be overlooked even in neonates especially with sudden onset of respiratory distress, cough or hoarseness in absence of fever.

Dyspnea↗
PubMedDate not supplied

Comparison of clastogenic effects of antimony and bismuth as trioxides on mice in vivo.

Comparison of the clastogenic effects of antimony and bismuth used as trioxides, when administered orally by gavaging to laboratory bred male mice, showed that the former was more strongly clastogenic than the latter. Three doses of each chemical (400, 666.67, and 1000 mg/kg body wt), corresponding to 1/50, 1/30, and 1/20 of oral LD50 of antimony trioxide, were fed daily to sets of mice up to 21 d. Animals were sacrificed on day 7, 14, and 21 of the experiment. Chromosomal aberrations and mitotic index were studied from bone marrow cells following a colchicine-air drying Giemsa schedule. The frequencies of chromosomal aberrations induced by both chemicals were directly proportional to the dose used and the duration of exposure, indicating their cumulative effects on the organism. The highest dose of antimony, given for the longest period was, however, lethal. Effects on germ cells, as shown by screening for sperm head abnormalities, were not significant.

Animals↗
PubMedDate not supplied

Acoustic versus phonetic representation of speech as reflected by the mismatch negativity event-related potential.

The concept of categorical perception of speech and speech-like sounds has been central to models of speech perception for decades. Event-related potentials (ERPs) provide a neurophysiologic perspective of this important phenomenon. In the present experiment the mismatch negativity (MMN) event-related potential, which is sensitive to fine acoustic differences, was recorded in adults. Of interest was whether the MMN reflects the acoustic or categorical perception of speech. The MMN was elicited by stimulus pairs (along a continuum varying in place of articulation from /da/ to /ga/) which had been identified as the same phoneme /da/ (within category condition) and as different phonemes /da/ and /ga/ (across categories condition). The acoustic differences between these two pairs of stimuli were equivalent. The MMN was observed in all subjects both in the within and across category conditions. Furthermore, the MMN did not differ in latency, amplitude or area within and across categories. That is, the MMN indicated equal discrimination both across and within categories. These results suggest that the MMN appears to reflect the processing of acoustic aspects of the speech stimulus, but not phonetic processing into categories. The MMN appears to be an extremely sensitive electrophysiologic index of minimal acoustic differences in speech stimuli.

Acoustic Stimulation↗
PubMedDate not supplied

Mismatch negativity in school-age children to speech stimuli that are just perceptibly different.

The mismatch negativity event-related potential (MMN) was elicited in normal school-age children in response to just perceptibly different variants of the speech phoneme /da/. A significant MMN was measured in each subject tested. Child and adult MMNs were similar with respect to peak latency and duration. Measures of MMN magnitude (peak-to-peak amplitude and area) were significantly larger in children than in adults. The results of the present study indicate that the MMN can be elicited in response to minimal acoustic stimulus differences in complex speech signals in school-age children. The results support the feasibility of using the MMN as a tool in the study of deficient auditory perception in children.

Acoustic Stimulation↗
PubMedDate not supplied

Correlates of early- and late-onset alcohol dependence.

The present study aimed at finding out demographic, clinical, personality, and behavioural correlates of age at onset of alcohol dependence. Fifty-one male patients of alcohol dependence (DSM-III-R, APA, 1987) attending the drug de-addiction clinic of a general teaching hospital in India comprised the sample. They were administered a composite socio-demographic and alcohol use proforma, modified Sensation-Seeking Scale (SSS), Multiphasic Personality Questionnaire (MPQ), and a checklist of behavioural tendencies when drinking. The early-onset alcoholics (age at onset of alcohol dependence 25 years or less) were younger. They had a larger proportion of first-degree relatives with both lifetime use and abuse/dependence of alcohol but not of other psychoactive substances. They had experienced a greater number of alcohol-related problems in the previous 1 year. They were also higher sensation seekers, higher on the Psychopathic deviate scale of MPQ, and tended to display aggression, violence, and general disinhibition when drinking. The late-onset alcoholics (age at onset of alcohol dependence more than 25 years) were anxiety-prone and guilt-ridden, and had less alcohol-related problems. The two groups were comparable on duration, frequently, and quantity of alcohol consumption. The findings are discussed in relation to some of the recently proposed typologies of alcoholism.

Adult↗
PubMedDate not supplied

Teratogenic effects of lithium and ethanol in the developing fetus.

Prolonged administration of either lithium (7 mg/kg body wt.) or ethanol (30% of daily caloric intake) for 10 days to pregnant rats results in several anatomical abnormalities in the fetus. Intragastric administration of lithium carbonate to pregnant rats immediately after confirmation of pregnancy resulted in high incidence of cleft palate, growth retardation, brain liquification and pulpy brain, hepatomegaly and digital abnormalities, when compared to the saline-treated controls. Furthermore, lithium administration during gestation also resulted in other less frequently observed abnormalities in the fetus, e.g., cardiomegaly, hydronephrosis, ankle-joint defects, syndactyly, defected ribs and sternum ossification defects. Chronic ethanol consumption by pregnant rats during early gestation also resulted in several anatomical abnormalities of prenatal growth retardation, resorption and still births, cleft palate, hydrocephaly and hydronephrosis. The severity and frequency of several of the fetal abnormalities were compounded when lithium and ethanol were administered simultaneously. The possible mechanisms of lithium and ethanol teratogenicity and their synergistic effects have been explained on a biochemical basis.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

Development of hepatic bilirubin glucuronidation as affected by prolonged maternal ethanol intake.

Prolonged maternal ethanol intake by lactating mothers resulted in a 26% and 41% decrease in serum conjugated bilirubin of 6 and 10 day old suckling newborn rats, respectively. An increase of 20% and 36% was observed in the serum unconjugated bilirubin levels in suckling newborns from the ethanol-fed group compared to the corresponding controls. Newborns suckling on ethanol-fed dams showed a small, but significant hyperbilirubinemia compared to the controls. Acute administration of ethanol (2.5 g/kg) to newborn rats also resulted in a decrease in serum conjugated bilirubin and an increase in the levels of unconjugated and total bilirubin. Prolonged ethanol intake by adults also resulted in a decrease in conjugated bilirubin and an increase in unconjugated and total bilirubin levels compared to the corresponding controls. Bilirubin glucuronide formation in the liver was decreased by ethanol by about 30% and 37% in the suckling newborn, and adults, respectively. Newborns suckling on ethanol-fed dams, as well as the dams consuming ethanol showed an increase in hepatic (UDPG)/(UDPGA) levels. The activity of hepatic bilirubin-UDP-glucuronyl transferase either in the newborns suckling on ethanol-fed dams, or in dams consuming ethanol chronically, was not significantly different from their corresponding controls. Ethanol was found to inhibit the glucuronidation of bilirubin by decreasing the availability of UDP-glucuronic acid in the newborn and adult livers.

Animals↗
PubMedDate not supplied

Novel biotinylated phenylarsonous acids as bifunctional reagents for spatially close thiols: studies on reduced antibodies and the agonist binding site of reduced Torpedo nicotinic receptors.

We synthesized three novel organoarsenicals as prototype bifunctional reagents for spatially close thiols, N-(4-arsenosophenyl) hexahydro-2-oxo-(3aS,4S,6aR)-1H-thieno[3, 4-d]imidazole-4-pentamide (1), 2-[4-[(4-arsenosophenyl)amino]-1, 4-dioxobutyl] hydrazide, (3aS,4S,6aR)-hexahydro-2-oxo- 1H-thieno[3, 4-d] imidazole-4-pentanoic acid (2), and [4-[[12-[[5-[(3aS,4S, 6aR)-hexahydro-2-oxo-1H-thieno[3, 4-d]imidazol-4-yl]-1-oxopentyl]amino]-1-oxododecyl]amino]phe nyl]-arso nous acid (3) containing both biotin and arsenic with intervening varying length spacers extending from 2 to 15 A beyond biotin bound to streptavidin. Conceptually, the arsenical group can form a stable, covalent ring structure with appropriately spaced thiols and thereby anchor the reagent to a macromolecule, while biotin allows for the detection of the reagent-macromolecule complex via avidin binding. Because the alpha-subunits of all characterized nicotinic receptors contain an easily reducible disulfide bond between adjacent cysteine residues, the reduced alpha-subunit is an attractive site for labeling. Compounds 1-3 all simultaneously bound streptavidin and dithiols, and all three decreased the number of [125I]alpha-bungarotoxin-binding sites in reduced Torpedo nicotinic receptors (IC50s 10-300 nM). Moreover, arsenylation of the receptors prevented their reoxidation with dithio-bis(nitrobenzoic acid), was reversible with 2,3-dimercaptopropanesulfonic acid, and protected the receptor from irreversible alkylation by bromoacetylcholine. However, in no case did 1-3 allow simultaneous binding to reduced nicotinic receptors and to [125I]streptavidin, although 3 alone allowed simultaneous labeling of a spatially close dithiol located in reduced antibodies.

Animals↗
PubMedDate not supplied

alpha-Ketoglutarate assay based on fluorescence quenching by NADH.

A new assay procedure for the measurement of ketoglutarate concentrations is described which is based on substrate-induced quenching (SIQ) of a fluorophore. The method makes use of the photoreaction between a fluorophore (thionine) and NADH. The latter is consumed during an enzymatic reaction between ketoglutarate and L-glutamic dehydrogenase. The conversion yield of cofactor from its reduced form to oxidized forms represented as an overall change in the population of the excited state population of the fluorophore thionine. An empirical relation is described that correlates initial substrate concentration to the observed yield of the cofactor conversion via a fluorescence recovery constant,Kt. The analysis of data obtained over a range of 0-500 microM results in a constant of 2748 M-1. The applicability of the proposed method is demonstrated by performing the assay for alpha-ketoglutarate in human urine. The ketoglutarate SIQ assay was not affected by the background interference that is inherent to this complex matrix.

Buffers↗
PubMedDate not supplied

Survey of termite-inhabited soil and mosquito breeding sites in Lucknow, India for potential mycopathogens of Anopheles stephensi.

During a short survey of soil and mosquito breeding sites in Lucknow, India for potential mycopathogen from a period of August-October 1996, 11 species of fungi in 5 genera were isolated using live mosquito larvae as host, Aspergillus flavus, A. fumigatus and Fusarium semitectum were the most frequently isolated species. Other fungi recorded were A. niger, A. ochraceus, A. terreus, A. versicolor, Geotrichum candidum, Penicillium verrucosum, Paecilomyces sp. and Fusarium sp. (Liseola/Elegans complex). Insect cell walls are known to contain chitin, so fungal isolates were tested for their chitinase activity on semi synthetic medium containing colloidal chitin. High chitinolytic activities were observed with A. flavus and A. ochraceus. Chitinase producers can be considered as potential pathogens. However, the higher incidence of F. semitectum could not be explained by inability to utilize chitin.

Animals↗
PubMedDate not supplied

Cell-cycle regulatory sequences in a hamster histone promoter and their interactions with cellular factors.

Knowledge of how genes are regulated during the cell cycle is essential for understanding the process of cell growth on a molecular level. Numerous studies have established that, as mammalian cells go through the cell cycle, histone mRNA levels change, the largest amount being produced in the S phase. Both transcriptional and post-transcriptional mechanisms are responsible for this regulation and it has recently been demonstrated that nucleotide sequences in both the 5' and 3' termini of the histone gene are involved. From deletion analysis of a hamster H3.2 fusion gene, we report here that the crucial control signals for both cell-cycle regulation and high level expression in vivo are contained in a 32-nucleotide (nt) region about 150 nt upstream of the TATA sequence and do not require any histone protein coding sequence. By comparison, the promoter of the herpes simplex virus (HSV) thymidine kinase gene is serum-stimulated but not cell-cycle regulated. The cell-cycle control exerted by the histone DNA regulatory element acts at the transcriptional level, as the rate of transcription is stimulated during the DNA synthetic phase of the cell cycle. Using DNA-protein mobility shift experiments, we demonstrate the existence of high affinity cellular factors interacting with the histone H3.2 promoter sequence. The concentration of the protein-DNA complexes shows cell-cycle variation, particularly during the transition from late G1 to the DNA synthesis phase. These data provide evidence for in vivo interactions between the cell-cycle transcriptional regulatory factors and the cis-acting DNA domain.

Animals↗
PubMedDate not supplied

Use of the domestic Swine as an alternative animal model for conducting dermal irritation/corrosion studies on fatty amine ethoxylates.

The dermal irritation/corrosion potential of four fatty amine ethoxylates was evaluated using domestic swine as an alternative animal model. The weanling pig was chosen for this study due to the similarity of its skin to human skin with respect to structure and physiology. The four products, Armostat 310 (tallow bis (2-hydroxyethyl) amine), Armostat 410 (coco bis (2-hydroxyethyl) amine), Armostat 710 (oleyl bis (2-hydroxyethyl) amine), and Armostat 1800 (stearyl bis (2-hydroxyethyl) amine) were applied to the skin of three domestic swine for 4 hours in accordance with internationally accepted guidelines. Dermal reactions were scored up to 168 hours post application. Armostat 310, Armostat 410, and Armostat 710 were all classified as moderately irritating, whereas Armostat 1800 was nonirritating. None of the additives were corrosive to the skin of domestic swine. These products had been previously classified as corrosive based on studies conducted with rabbits using Armostat 310. This study demonstrates that the use of a more appropriate animal model will generate data that are relevant to humans for the classification of the potential dermal irritation and/or corrosive properties of chemicals.

Administration, Cutaneous↗