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Biomedical subjects

S Mehta

Publications and source records attributed to S Mehta.

At least 361 records · Page 20Linked to original sources

Treatment of experimental Pseudomonas corneal ulcers with enoxacin, a quinolone antibiotic.

Enoxacin is a broad-spectrum quinolone-derivative antibiotic. In a rabbit model of keratitis caused by a Pseudomonas species, enoxacin (3 mg/mL) was as effective as gentamicin sulfate (3 mg/mL) and enoxacin (10 mg/mL) in reducing viable bacterial counts in corneas after 24 hours of hourly therapy with eye drops. Bacterial counts were reduced by about 5000-fold by enoxacin treatment when compared with placebo-treated controls. Penetration studies of topical enoxacin (3 mg/mL) showed that concentrations in cornea and aqueous humor reached levels above reported minimal inhibitory concentrations when an epithelial defect was present. Further investigation of enoxacin for treatment of ocular disease is warranted.

Animals↗

pH-dependent bactericidal barrier to gram-negative aerobes: its relevance to airway colonisation and prophylaxis of acid aspiration and stress ulcer syndromes--study in vitro.

pH-Dependent bactericidal activity on four gram-negative bacilli that are mainly responsible for gastric to airway colonisation has been investigated. Organisms studied were Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae and Serratia marcescens. At pH of the medium adjusted to 2.7 or lower all four organisms were killed in 1.5 h. At pH 3.1 or greater, no reduction in viable bacterial number was noted over 2 h. Even when pH of the medium was adjusted to 6.8, no increase in bacterial count was observed in 4 h. Relevance of these findings in relation to airway colonisation and prophylaxis of acid aspiration and stress ulcer syndromes is discussed. It is suggested to maintain pH of the gastric contents above 4.0 by H2 antagonists and prevent growth of gram-negative organisms in the stomach by keeping it empty.

Culture Media↗

Phase II randomized comparative clinical trial of Norplant (six capsules) with Norplant-2 (two covered rods) subdermal implants for long-term contraception: report of a 24-month study. National Programme of Research in Human Reproduction.

In a randomized clinical study, contraceptive efficacy and bleeding patterns were studied in a group of healthy, regularly menstruating, non-lactating women (n = 84) using two 4.4 cm covered silastic rods containing levonorgestrel, Norplant(R)-2, and compared with another group of women (n = 88) using six 3.4 cm capsules also containing levonorgestrel, Norplant(R). The silastic rods or capsules were placed subdermally in the medial aspect of the upper arm. No method failure was reported up to 24 months of use in this study with either of the device. The bleeding pattern was also similar for both devices as indicated by average episode length, number of bleeding runs and number of spotting days. The continuation rates with both devices were over 80 per 100 users at the end of 12 months and over 65 per 100 users at the end of 24 months. Discontinuations due to expulsion of the device, bleeding problems or personal reasons were few and similar for both devices. The results suggest that silastic-covered rods, Norplant(R)-2, which are comparatively easier to insert and remove and have similar clinical effect, could replace capsules, Norplant(R), as a long-term reversible subdermal contraceptive.

Adolescent↗

Effect of protein calorie malnutrition on peripheral nerves. A clinical, electrophysiological and histopathological study.

Forty-three children (aged 7 to 62 months) with protein calorie malnutrition (PCM) were studied; 13 had mild to moderate PCM and 30 severe PCM. A reduction of motor nerve conduction velocity and abnormalities of sensory conduction were present in both groups. The abnormality of motor nerve conduction was directly related to the severity of PCM and the presence of hypotonia and/or hyporeflexia. Sural nerve biopsies from both groups were studied for myelinated fibre density, fibre size spectrum, relationship of internodal length with diameter and qualitative light microscopic changes. The biopsies from children with mild to moderate PCM were characterized by a normal developmental change in myelinated fibres with an increasing proportion of medium and large size fibres, a transition from a unimodal to a bimodal distribution and an appropriate relationship of internodal length to fibre diameter. Evidence of mild segmental demyelination was observed in only one patient of this group. In contrast, in the biopsies from children with severe PCM, the normal developmental pattern for myelinated fibre size distribution was impaired with a persistence of small myelinated fibres, and there was a failure of internodal segments on large fibres to elongate with increase in age and significant segmental demyelination in about 50 per cent of cases. Retarded myelination and segmental demyelination probably form the morphological basis for impaired peripheral nerve function in PCM. Short internodes on large diameter fibres may also contribute to this effect.

Child, Preschool↗

Work practices relating to intubation in operating rooms in Sweden.

A survey into the current usage of tracheal tubes in operating rooms was carried out in Sweden by sending a questionnaire to anaesthetists in charge of anaesthetic departments in 90 acute hospitals, which included seven teaching hospitals. The object was to determine how far the recent advances in tube, cuff design, and material had influenced the attitudes and work practices of anaesthetists. Fifty-eight replies were recorded (a 64.4% response rate). All teaching hospitals and the majority of other hospitals favoured tubes with high-volume, low-pressure cuffs. Most hospitals used size 9 orotracheal tubes in adult male and size 8 in adult female patients. Seventy-one per cent of teaching hospitals used both local anaesthetic jelly for lubricating tubes and topical laryngeal spray prior to intubation. Nasal decongestants were used by only 14.2% of teaching hospitals prior to nasal intubation. Over three-fourths of the hospitals were in favour of inflating the cuff to no-leak ventilation. Just over half of non-teaching hospital and two-thirds of teaching hospital monitored intracuff pressure.

Anesthesia↗

Work practices relating to intubation and associated procedures in intensive care units in Sweden.

A survey into the current usage of tracheal tubes and associated procedures, such as various sedation regimes and antacid therapy, in intensive care units was carried out in Sweden by sending a questionnaire to physicians in charge of intensive care units in 70 acute hospitals which included seven main teaching hospitals. The purpose of the survey was to see how far the recent advances in tube and cuff design and awareness of the problems caused by prolonged therapeutic paralysis in intensive care units have influenced the attitudes and work practices of physicians in Sweden. Forty-nine replies were received (a 70% response rate). All hospitals used polyvinyl chloride tubes of Magill design, with high residual volume, low pressure cuffs. Intensive care units in 85.7% of teaching hospitals and 47.6% of non-teaching hospitals preferred the nasal route for intubation. Most non-teaching hospitals used a size 7 tube in both adult male and female patients for nasal intubation. The majority of units changed from tracheal tubes to tracheostomy after a period of 1-2 weeks. 85% of all hospitals monitored intracuff pressure as a routine, and in most intensive care units the cuff was inflated to no-leak ventilation. The majority of units rarely used muscle relaxants. Phenoperidine and diazepam were the most popular drugs used for the sedation technique. 71.4% of teaching hospitals and 40.9% of non-teaching hospitals used antacids routinely in patients on intermittent positive pressure respiration. The results are discussed.

Anesthesia↗

Disposition of chloramphenicol in young rhesus monkeys with protein-energy malnutrition.

The disposition of chloramphenicol was studied in young rhesus monkeys at three levels of nutrition: control, protein-energy deficiency, and following nutritional rehabilitation. During the malnutrition phase, the plasma elimination half-life was prolonged and the plasma clearance was reduced. Simultaneously there was a decrease in the activity of chloramphenicol-specific UDP-glucuronyl transferase. These changes were reversible following nutritional rehabilitation.

Animals↗

Chemiluminescence in neutrophils and Lettré cells induced by myxoviruses.

Luminol-mediated chemiluminescence in neutrophils is stimulated by Sendai virus and by influenza virus; Lettré cells also exhibit chemiluminescence (less than 10% of that of neutrophils), which is stimulated by Sendai virus and by influenza virus. Virally induced permeability changes are not responsible for chemiluminescence, since (i) extracellular Ca2+ inhibits permeability changes but stimulates chemiluminescence, and (ii) influenza virus, which induces permeability changes at pH 5.3 but not at pH 7.4, induces chemiluminescence at either pH. Other agents [zymosan, N-formyl-L-methionyl-L-leucyl-L-phenylalanine, 4-phorbol 12-myristate 13-acetate (phorbol ester), A23187] likewise induce chemiluminescence in the absence of permeability changes.

Animals↗

Indian Council of Medical Research. Task Force on Hormonal Contraception: Phase II randomized clinical trial with norethisterone oenanthate 50 mg alone and in combination with 5 mg or 2.5 mg of either estradiol valerate or cypionate as a monthly injectable contraceptive.

A Phase II multicentric study was carried out to compare the different contraceptive treatment schedules of the monthly injectable consisting of norethisterone oenanthate (NET OEN) 50 mg either given alone or in combination with estrogen esters, 2.5 or 5 mg of estradiol valerate (E2 Val.) or estradiol cypionate (E2 Cyp.). A total of 364 women were observed for 1686 months of use. Analysis of the bleeding pattern data indicated that NET OEN 50 mg when given alone gave rise to delayed cycles and/or amenorrhoea. However, the addition of estrogen esters in a dose of either 2.5 or 5 mg provided significantly better bleeding patterns. Of the different treatment schedules investigated, the combination of NET OEN 50 mg with E2 Val. 5 mg provided more consistent and better cycle control. These findings however need further validation on a larger study sample.

Adult↗

Interaction of influenza virus haemagglutinin with cell membranes.

Influenza virus causes susceptible cells to undergo haemagglutination, haemolysis and oxygen radical formation. Each activity is the result of an interaction between the haemagglutinin (HA) glycoprotein and the cell plasma membrane, and appears to involve three discrete functions of the HA glycoprotein.

Cell Membrane↗