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Biomedical subjects

F W Johnson

Publications and source records attributed to F W Johnson.

At least 37 records · Page 2Linked to original sources
PubMed1983

Simple transport medium for the isolation of Chlamydia psittaci from clinical material.

Infectious elementary bodies of Chlamydia psittaci in tissue samples from field cases of enzootic abortion were placed in five different transport media (A to E). In one medium, in the absence of refrigerative storage, the organism remained viable for 30 days and at 4 degrees C for 34 days. This was medium D; it consisted of sucrose (74.6 g/litre), K2HPO4 (1.237 g/litre), L-glutamic acid (0.721 g/litre), fetal calf serum (10 per cent v/v), vancomycin and streptomycin (100 micrograms/ml) and nystatin and gentamicin (50 micrograms/ml). Samples of this transport medium were supplied to veterinary investigation centres throughout the UK. Of 1862 samples submitted for diagnosis of enzootic abortion only 1.55 per cent were so contaminated that chlamydiae could not be detected. This transport medium permits the isolation of C psittaci from clinical material for up to about one month, even in the absence of conventional storage facilities.

Abortion, Veterinary↗
PubMed1983

Susceptibility of Chlamydia psittaci (ovis) to antimicrobial agents.

Minimum inhibitory (MIC) and minimal lethal (MLC) concentrations of 30 antimicrobial agents were determined for field strains and for the A22 EAE vaccine strain of Chlamydia psittaci (ovis). No differences in susceptibility could be detected between strains. The antimicrobials could be divided into four groups. Group A had no effect on growth and development, Group B were bacteriostatic at concentrations in excess of 100 mg/l, Group C were bacteriostatic at concentrations of 10 mg/l or less but were bactericidal at concentrations above 10 mg/l and Group D were bactericidal at concentrations above 0.5 mg/l. The value of antimicrobials in aiding diagnosis and in the therapy of chlamydial abortion of ewes is discussed.

Anti-Bacterial Agents↗
PubMed1982

Ovine enzootic abortion: the acquisition of infection and consequent abortion within a single lambing season.

The spread of enzootic abortion was observed in a flock of 37 unvaccinated Scottish blackface ewes, in mid-pregnancy at the start of the trial. Eight ewes were infected with the ZC 26 strain of chlamydia and allowed to run with 29 untreated controls until lambing was completed. All eight inoculated ewes aborted between 26 and 51 days after infection and chlamydial infection was demonstrated in seven of the abortions. Complement fixing antibodies were not detected in the controls until nine days after the first infected abortion, but within four weeks 69 per cent of the control ewes had developed significant complement fixation titres. Ten of the control ewes lost lambs, chlamydial infection was demonstrated in seven cases, two were undiagnosed and one was attributed to dystocia. The seven infected cases occurred between 69 and 87 days after the start of the trial and coincided with a further rise in the percentage of seropositive controls to a maximum of 90 per cent by the end of lambing.

Abortion, Veterinary↗
PubMed1978

Development of a practical membrane lung system.

The purpose of this study was to evaluate a compact, single-pump membrane oxygenator system designed for both short-term open-heart procedures and long-term extracorporeal support. Work was directed at developing a compatible, disposable venous reservoir, fabricating a compact mounting board, determining acceptable priming volumes, and establishing safe and effective modes of setup and operation. Ten adult baboons undergoing total cardiopulmonary autotransplantation as part of a separate study were operated on using a 1.5 m2 Kolobow spiral-coil membrane system. Blood gases, oxygen transfer, extracorporeal blood flows, priming volume, and setup times were determined. In addition, 3 infant and 6 adult human subjects undergoing cardiac operations in which spiral-coil membranes of various sizes were used were also similarly studied. The data and experience from these studies suggest that the spiral-coil membrane system utilized is safe and effective in procedures requiring short-term cardiopulmonary bypass.

Adolescent↗
PubMed1977

Neonatal conjunctivitis caused by Neisseria gonorrhoeae and Chlamydia trachomatis.

In a selected group of 103 babies referred with neonatal conjunctivitis Neisseria gonorrhoeae was isolated from 11 and Chlamydia trachomatis from 33. Concurrent infection was present in three. On toddler sibling developed chlamydial conjunctivitis. After treatment C. trachomatis was re-isolated from six babies during the follow-up period. The discharge started one to three days after delivery in only three babies with gonococcal conjunctivitis and at five to eight days in eight babies. One baby was delivered by caesarean section. N. gonorrhoeae was isolated from four asymptomatic fathers, all of whom had urethritis. The mean onset of discharge in the 33 babies from whom Chlamydia was isolated was 7-1 days. One baby was delivered by caesarean section. Chlamydial conjunctivitis was associated with a high incidence of prematurity and of postpartum infection in the mother. Ten fathers of Chlamydia-positive babies were examined. C. tachomatis was isolated from four, all of whom were asymptomatic but had low-grade urethritis. These findings confirm the pathogenic role of C. trachomatis in the cervix and indicate the importance to the family of an adequate microbiological investigation of neonatal conjunctivitis.

Adult↗
PubMed1976

Rapid long tube intubation of the jejunum by a new endoscopic device.

Despite the advantages of aseptic nonoperative intubation of the small intestine for decompression of obstructed loops, 48% of the attempts lead to failure to pass the tube through the pylorus. The difficulty and inconvenience of passage beyond the stomach have been overcome by the development of a special tube attachment adapted to a fiberoptic duodenoscope (Olympus Model GIF-K). Under direct endoscopic vision the tube can be carried into the second and third portion of the duodenum, released from the scope, and then further prodded into the jejunum. The entire procedure takes less than 15 minutes. Rapid intubation has now been easily carried out in five patients. Three patients had mechanical bowel obstruction. Rapid and effective decompression allowed adequate time for stabilization of concomitant serious problems such as (1) marked cardiopulmonary dysfunction secondary to a near fatal pulmonary embolus, (2) severe peritonitis post appendectomy, and (3) acidosis and dehydration. Surgical correction of the obstructing lesions was safely deferred for up to one week until the concomitant problems improved. The fourth patient, who was a renal transplant recipient, had chronic gastric ileus secondary to duodenal ulcer. Rapid passage of the long tube into the jejunum allowed restoration of nutrition and avoidance of gastrostomy. The fifth patient, with an ileus secondary to an infected abdominal aortic graft, underwent successful decompression but died of sepsis. He represents the only mortality. We propose that jejunal intubation using our technic is not only rapid but relatively easy and should encourage the wider acceptance of aseptic long tube intestinal decompression.

Adult↗
PubMed1976

Factors affecting the sensitivity of replicating McCoy cells in the isolation and growth of chlamydia A (TRIC agents).

Normal non-irradiated McCoy cell cultures provide a sensitive and reproducible method for the isolation of oculo-genital strains of chlamydia A directly from human secretions and for laboratory studies with these agents. Since September 1973, chlamydia have been isolated from 175 of 562 women (32-1%) attending venereal disease clinics. Freshly isolated and low passage strains have been used to determine the importance of centrifugation, constitution and pH of the tissue culture medium, and the temperature of incubation in controlling the efficiency of plating in the method.

Cells, Cultured↗