Biomedical subjects

J Chawla

Publications and source records attributed to J Chawla.

6 recordsLinked to original sources

PubMed1992

Scanning electron microscopy of bacterial biofilms on indwelling bladder catheters.

Fifty Foley bladder catheters that had been indwelling for periods ranging from 3 to 83 days (mean 35 days) were examined for the presence of bacterial biofilm. Scanning electron microscopy on freeze-dried cross-sections and fixed, critical point-dried longitudinal sections revealed biofilm formation on the luminal surfaces of 44 of the catheters. Culture of urine samples and sonicates from catheters revealed that the prevalence of bacteriuria was less than that of catheter colonization. A wide range of nosocomial species were found colonizing the catheters, Escherichia coli being most often isolated. The bacterial composition of the biofilms ranged from single species to mixed communities containing up to four species. There was no relationship between the length of time that the catheter had been in situ and the extent of biofilm formation. The biofilms varied in thickness from 3 to 490 microns and were visible as layers of bacterial cells up to about 400 cells deep, embedded in a matrix.

Bacterial Adhesion↗

PubMed1992

Virulence factors in Escherichia coli from urinary tract infections in patients with spinal injuries.

A collection of 70 strains of Escherichia coli from urinary tract infections in spine-injured patients undergoing long-term bladder catheterization were tested for characteristics that have been associated with the ability to produce pyelonephritis. The incidence of the virulence factors were: mannose-resistant haemagglutinins (30%), P-fimbriae (17%), haemolysin (27%), K-antigens (28%) and aerobactin (by bioassay 33%, by gene probe 39%). Only 54% of the strains belonged to the O-serotypes usually associated with urinary tract infections. E. coli carrying the full complement of virulence factors were rare in the urinary tract of the spinal patients and were not associated with episodes of symptomatic pyelonephritis. It is clear that the neuropathic bladder and the presence of the catheter permits a wide variety of bacterial types to colonize the urinary tract and cause infection of the kidney. The identification of host markers rather than bacterial factors is suggested as a more fruitful approach to the early detection of cases likely to progress to pyelonephritis in this group of patients.

Cross Infection↗

PubMed1992

The effect of intravesical Marcain instillation on hyperreflexic detrusor contractions.

Thirty-six patients with suprasacral spinal injury were treated with intravesical local anaesthetic instillation. Eighteen of 32 patients (56%) were converted from an 'ice water positive' hyperreflexic state to an 'ice water negative' state by bupivacaine hydrochloride. Four patients treated with lignocaine hydrochloride showed no benefit. Intravesical local anaesthetic instillation is suggested as a possible treatment for selected cases of detrusor hyperreflexia in patients on intermittent catheterisation.

Administration, Intravesical↗

PubMed1991

Activity of some antiseptics against urinary tract pathogens growing as biofilms on silicone surfaces.

The activity of chlorhexidine, mandelic acid and a mandelic/lactic mixture were tested against biofilms of four species of gram-negative nosocomial organisms that commonly infect the catheterized urinary tract. Cells growing on silicone discs were exposed to concentrations of agents used in bladder instillation. Citrobacter diversus biofilms proved to be sensitive to all three agents. Pseudomonas aeruginosa, Proteus mirabilis and Klebsiella pneumoniae all survived well in chlorhexidine but their viability was significantly reduced by the mandelic acid formulations. These results suggest that bladder instillations of mandelic acid or mandelic/lactic acids would be more effective than chlorhexidine in eliminating biofilms from catheter surfaces.

Anti-Infective Agents, Urinary↗

PubMed1977

Identification of semen in 500 patients seen because of rape.

Of 500 patients seen because of rape, semen was identified in vaginal secretions by the identification of spermatozoa in 61%, by an acid phosphatase value of 50 units or more in 40%, and by the identification of a foreign blood group substance or a high titer of own blood group substance in 16%. The addition of the determination of the acid phosphatase to the search for spermatozoa identified semen in only 1.4% more patients, or a total of 62.4%. Identification and titers of blood group substance were confirmatory only, but further characterized the source of the semen in 25% of those patients with spermatozoa. Spermatozoa were identified for as long as 48 hours, and elevated acid phosphatase was not found after 18 hours. Acid phosphatase was elevated in only 62% of patients with spermatozoa.

ABO Blood-Group System↗

PubMed1975

EEG in brain abscess: its value in localization compared to other diagnostic tests.

The EEG records of 13 cases of brain abscess were reviewed for their value in localization. Of the 11 cases of supratentorial abscesses localization was achieved in 10, and correct lateralization in the remaining 1 case. Two other cases were cerebellar abscesses; 1 of them showed a false cerebral localization; the other showed no focal abnormalities. The most consistent EEG localizing sign was focal arrhythmic delta waves. These were as slow as 0.5 c/sec in 6 of the 13 cases. Epileptiform discharges in the pre-operative EEG were seen in 4 of the 13 cases. Asymmetry of beta activity correctly lateralized the abscess in 7 of the 11 supratentorial abscesses. Generalized abnormalities when present correlated with depression of consciousness rather than with the duration of illness or the presence of raised intracranial pressure. Indium brain scans were done in 6 supratentorial abscesses and provided correct or approximate localization in 5. Carotid angiograms were also done in 7 cases and localized the abscess in 6. Our findings show that the EEG is comparable to brain scans and contrast radiological studies in localizing supratentorial abscesses. We feel that the combination of EEGs and brain scanslization in suspected brain abscess.

Adolescent↗