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Biomedical subjects

R M Joshi

Publications and source records attributed to R M Joshi.

At least 19 recordsLinked to original sources
PubMed1998

Crystal structure of Boc-LAla-deltaPhe-deltaPhe-deltaPhe-deltaPhe-NHMe: a left-handed helical peptide.

Alpha,beta-dehydrophenylalanine residues constrain the peptide backbone to beta-bend conformation. A pentapeptide containing four consecutive (deltaPhe) residues has been synthesised and crystallised. The peptide Boc-LAla-deltaPhe-deltaPhe-deltaPhe-deltaPhe+ ++-NHMe (C45H46N6O7, MW = 782.86) was crystallised from an acetonitrile/methanol mixture. The crystal belongs to the orthorhombic space group P2(1)2(1)2(1) with a = 19.455(6), b = 20.912(9), c = 11.455(4) A and Z = 4. The X-ray (MoKalpha, lambda = 0.7107 A) intensity data were collected using the Rigaku-AFC7 diffractrometer. The crystal structure was determined by direct methods and refined using the least-squares technique, R = 8.41% for 1827 reflections with absolute value of Fo > 4sigma(absolute value of Fo). The molecule contains the largest stretch of consecutive dehydrophenylalanine residues whose crystal structure has been determined so far. The peptide adopts left-handed 3(10)-helical conformation despite the presence of LAla at the N-terminus. The mean phi, psi values, averaged across the last four residues are 56.8 degrees and 17.5 degrees, respectively. There are four 4-->1 intramolecular hydrogen bonds, characteristic of the 310-helix. In the crystal each molecule interacts with four crystallographically symmetric molecules with one hydrogen bond each.

Circular Dichroism↗
PubMed1997

Palliative surgery in malignant obstructive jaundice: prognostic indicators of early mortality.

A prospective analysis of 50 patients undergoing palliative bypass surgery for incurable malignant obstructive jaundice was carried out in an attempt to identify factors predicting post-operative mortality. Five clinical and nine laboratory parameters were studied. Fourteen patients died within 30 days of surgery. It was seen that levels of haemoglobin, hematocrit and serum albumin levels were significantly lower while serum bilirubin was significantly higher in patients who died compared with the survivors. Patients having Hb < 10 Gm/dL, serum bilirubin > 350 micromol/dL, serum albumin < 2.5 g/dL and prothrombin index < 60% exhibited a higher percentage of mortality. On multivariate analysis, levels of haemoglobin, serum albumin and serum bilirubin could be used to independently predict the outcome with an accuracy of 86%. This was validated by prospectively applying the regression equation derived from the first 30 patients to the next 20 patients. It was seen that the predicted outcome correlated with the actual outcome with a correlation coefficient of 0.5098 (P = 0.01). It is concluded that in patients with high bilirubin, low haemoglobin and low albumin levels palliative surgical procedures carry a high risk of post-operative mortality and non-surgical methods may be more suitable.

Adult↗
PubMed1990

Antimicrobial susceptibility of non-penicillinase and penicillinase-producing Neisseria gonorrhoeae strains isolated in Tripoli, Libya.

Neisseria gonorrhoeae culture gave a positive result in 42 of 64 male adults with purulent urethral discharge. The majority of the infections were acquired outside Libya. Twenty-seven strains (64.3%) were non-penicillinase producing (NPPNG) and 15 (35.7%) were penicillinase producing (PPNG) by starch paper technique. Antimicrobial susceptibility of the strains to 5 antibiotics was carried out by agar-plate dilution technique. Twenty-three NPPNG strains (54.8%) were susceptible to penicillin with a minimum inhibitory concentration (MIC) of less than or equal to 0.5 micrograms/ml. In 4 strains (9.5%), a high resistance to penicillin (MIC greater than or equal to 16 micrograms/ml) appeared to be chromosomally-mediated (CMRNG). All PPNG strains were resistant to penicillin (MIC greater than or equal to 1 microgram/ml). While resistance to erythromycin (MIC greater than or equal to 1 microgram/ml) and tetracycline (MIC greater than or equal to 1 microgram/ml) was observed in 5 strains, resistance to kanamycin (MIC 32 micrograms/ml) and spectinomycin (MIC 64 micrograms/ml) was present in only one strain. Whereas no significant differences were recorded in MICs of erythromycin, tetracycline, kanamycin and spectinomycin between NPPNG and PPNG strains, one PPNG strain was found to be resistant in vitro to all 5 antibiotics.

Drug Resistance, Microbial↗
PubMed1989

Primary and acquired drug resistance in Mycobacterium tuberculosis strains in western region of Libyan Arab Jamahiriya.

Drug resistance in Mycobacterium tuberculosis strains prevalent in the Western Region of Libyan Arab Jamahiriya was studied for the years 1984, 1985 and 1986 at the regional tuberculosis control centre at Gurgi, Tripoli. Records of resistance to streptomycin, isoniazid, ethambutol and rifampicin were analysed. Whereas primary drug resistance was observed in 5.1%, 19.5% and 3.8%, acquired drug resistance was found in 12.2%, 34.0% and 15.3% of the strains in 1984, 1985 and 1986 respectively. Only 3 out of 598 strains (1.2%) were found to show acquired resistance to rifampicin. No primary resistance to rifampicin was observed. The situation of drug resistance in pulmonary tuberculosis in the Jamahiriya is discussed.

Drug Resistance, Microbial↗
PubMed1987

Shigellosis in Zaria, northern Nigeria.

368 strains of Shigella were recovered from stool specimens in the Department of Medical Microbiology, Ahmadu Bello University Teaching Hospital, Zaria, during the period January 1980 to December 1984. S. flexneri was found to be the most common (60%) followed by S. boydii (20.7%), S. dysenteriae (14.1%) and S. sonnei (5.2%). Males were more frequently infected (61.4%) than females (38.6%). Maximum cases were seen in the 21-to 40-year age group (48.9%). Almost two-thirds of the cases of shigellosis (64.4%) were recorded during the rainy season. Antimicrobial resistance to four or more drugs was recorded in (38%) of the isolates.

Adolescent↗
PubMed1985

Pompe's disease.

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Female↗
PubMed1985

Limb-heart syndrome.

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Abnormalities, Multiple↗
PubMed1985

Sensitivity pattern and beta-lactamase screening of Neisseria gonorrhoeae strains isolated in Zaria, Northern Nigeria.

One hundred and sixty strains of N. gonorrhoeae were studied for their in-vitro sensitivity to six different antimicrobial agents and tested for beta-lactamase production in Zaria, Northern Nigeria. While 82% of strains were sensitive to erythromycin, 70% to tetracycline and 61% to chloramphenicol, only 35%, 33% and 24% were sensitive to ampicillin, penicillin and streptomycin respectively. Penicillin is no more the drug of choice in the treatment of gonorrhoea in this environment since two thirds of strains are either partially resistant or completely resistant to penicillin and 44% of strains are beta-lactamase producers. Erythromycin/tetracycline are recommended as the drugs of choice.

Anti-Bacterial Agents↗