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Biomedical subjects

L M Cobb

Publications and source records attributed to L M Cobb.

At least 55 records · Page 3Linked to original sources

Ectopic ureter with seminal vesicle insertion in an infant with tracheoesophageal fistula and possible adult polycystic kidney disease.

We report on a male newborn with a tracheoesophageal fistula and possible adult polycystic kidney disease as well as a single ectopic ureter with seminal vesicle insertion. There is an association of tracheoesophageal fistula, hindgut and sacral anomalies with ureteral ectopia but adult polycystic kidney disease has not been described. The diagnostic modalities currently available are discussed, as well as the implications of the association with other anomalies.

Abnormalities, Multiple↗

Further experiments to study whether localised fission fragment irradiation of rat lung causes tumours.

Male albino rats inhaled an aerosol of 235UO2 (mass median aerodynamic diameter = 2.8 micrometers and geometric standard deviation = 1.6). Approximately 20 h or 7 d post-inhalation the rats were exposed briefly to 10(12) slow neutrons cm-2 in a nuclear reactor, causing the retained 235UO2 particles of approximate mass 40 or 400 micrograms to emit fission fragments which irradiated the lungs. The mean absorbed doses from the fission fragments were either 80 ot 800 cGy approximately and in addition the lungs were exposed to a background of alpha-rays throughout the rats' life-time from the retained 235UO2 which gave mean doses of about half that from the fission fragments. The animals were kept for their life-time and killed when they became moribund. Malignant tumours were found in the lungs (squamous cell carcinoma and adenocarcinoma) which were probably induced by the alpha-rays rather than the fission fragments. Because of insufficient numbers of animals in the experimental groups, however, some statistical uncertainty exists as to whether the fission fragments were in fact less effective than the alpha-rays per unit absorbed dose in causing malignant tumours of the lung.

Adenocarcinoma↗

Surgical management of infantile (ectopic) ureteroceles: report of a modified approach.

Since 1970, our experience in managing 22 patients (24 renal units) with infantile (ectopic) ureteroceles suggests that no single procedure is universally applicable. Certain general principles, however, guide management strategy. First, preservation of the upper pole moiety is successful if there is functioning renal parenchyma on IVP (9 cases with one failure). Second, when extirpation is required, total ureterectomy-ureterocelectomy is unnecessary (13 cases with no reoperations specifically for stump extirpation). Third, urinary tract infections are fairly common in the first postoperative year (4 of 16 patients), being more common in children with common sheath ("double barrel") reimplantations. This review of our experience often showed the primary procedure to be long and difficult with significant blood loss. Although it did not occur in this series, devascularization of the lower pole ureter remains a danger. Therefore, a two-stage procedure was developed to obviate these problems. In the last 4 patients (5 renal units) in this series, the ureteroceles were first incised endoscopically. Six weeks later, reimplantation or upper pole nephrectomy-partial ureterectomy was performed. Adequate early decompression of the ureterocele resulted in less operative time and blood loss (average 27.5 cc for upper pole nephrectomy) at the subsequent procedure. We now prefer this method, especially in very young or compromised patients, although the follow-up time is inadequate to recommend it generally.

Child↗

A tube for enteral nutrition of patients with aphagopraxia and patients with ventilator assistance.

A new feeding tube was designed for use in patients who cannot swallow. A comparison of our ability to pass a commercially available, mercury weighted, small feeding tube or the new, nonweighted feeding tube was made. Forty-one consecutive patients who had endotracheal intubation and who had mechanical ventilation assistance or who had suffered injuries to the central nervous system, producing aphagopraxia were compared. In the 22 patients in whom the guided tube system was first tried, enteric support was possible in 20. Gastric placement was possible in only 12 of 19 patients in whom the mercury weighted tubes were first tried and in only one of these patients did the tube pass into the small intestine beyond the ligament of Treitz. Seventeen of 20 nonweighted tubes passed into the small intestine. The newly designed small feeding tube system should be used as the initial means of gaining access to the intestine for enteric nutritional support of patients in intensive care units and after strokes or neurologic injuries when the patient cannot swallow.

Deglutition Disorders↗

Effects of chronic inhalation of dimethyl ether in the rat.

Dimethyl ether (DME) is a colourless gas with an ethereal odour. It is used mainly as a liquid refrigerant and an aerosol dispersant. Little or no data exist on the toxicology of this material. In the present study, groups of male and female rats were exposed to 0.02%, 0.2% and 2% v/v of DME in air, 6 h/day, 5 days/week for 30 weeks. At the end of the study the high-dose level male rats showed a significant reduction on liver weight compared with the control group; this was accompanied by raising SGPT levels. In high-dose female rats there was no significant effect on liver weight but the SGPT levels were raised above control values. No histological abnormalities were observed in the liver or in any other organ.

Aerosols↗

The growth kinetics of xenografts of human colorectal tumours in immune deprived mice.

The technique of labelled mitoses was used to examine cell proliferation within grafts of human colonic and rectal tumours in immune deprived mice. Most of the data were obtained on the first passage but in some cases up to the third passage was used. It was found to be difficult to obtain precise kinetic data on this type of tumour material, but the results did allow some estimates to be made, particularly of the duration of the G2 and S phases of the mitotic cycle. The average G2 duration was 6 h and the average S phase was 14 h. It is concluded that whilst xenografts may differ in a number of respects from the tumour in the patient, they nevertheless constitute a type of experimental tumour that is worthy of further study.

Aged↗

The behaviour of carcinoma of the large bowel in man following transplantation into immune deprived mice.

The growth of carcinoma of the human large bowel was studied in the first 2 passages in immune deprived mice. The tumours were obtained from large bowel resections on 3 people. There was a strong histological similarity between the patient's tumour and the tumour that grew subcutaneously in the mice 2-8 months after implantation. One dissimilarity observed was a higher mitotic index in some of the tumours growing in the immune deprived animals. In the second passage of the bowel tumours, cells were implanted into groups of 8-10 animals in the following sites: subcutaneous, intramuscular, intravenous, intrahepatic, intraperitoneal and intrathoracic. Growth of tumour was observed from all 3 tumours when they were implanted subcutaneously, intramuscularly, intraperitoneally and intrathoracically. Infiltration of muscle by tumour was a frequent finding. Lung metastases developed after intravenous injection of cells in 1 of the 3 tumours. In none of the 3 tumours did growth follow injection of cells directly into the substance of the liver. On no occasions were spontaneous metastases observed.

Abdominal Muscles↗