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Biomedical subjects

A Cowen

Publications and source records attributed to A Cowen.

11 recordsLinked to original sources
PubMed1992

Loss of heterozygosity at the human RAP1A/Krev-1 locus is a rare event in colorectal tumors.

Kirsten-ras-revertant-1 (Krev-1/Rap1A) is a recently identified tumor suppressor gene which induces flat revertants when introduced into a variety of ras-transformed cell lines in vitro. Since 47% of colorectal carcinomas have transforming mutations in ras protooncogenes, and since Krev-1 is expressed at high levels in normal colonic mucosa, we hypothesized that inactivation at the Krev-1 locus may be necessary for transformation of colonic cells. Loss of heterozygosity is a common method of inactivation of tumor suppressor genes in colorectal tumors. Therefore, we analyzed loss of heterozygosity in 52 patients with sporadic colorectal cancer. Because Krev-1 had no previously described polymorphisms, we first identified a BclI restriction fragment length polymorphism which showed 40% heterozygosity in 50 unrelated individuals. However, only one tumor from 18 informative patients showed allelic loss at the Krev-1 locus. This suggests that loss of heterozygosity is not a common mechanism of inactivation at the Krev-1 locus in colorectal cancer. However, the results do not exclude a role for Krev-1 in the etiology of this neoplasm because inactivation may occur by other mechanisms.

Alkaline Phosphatase↗
PubMed1992

Collision.

Explore the source record for details and available documents.

Accidents, Aviation↗
PubMed1989

Oesophageal ruptures and perforations--a review.

Oesophageal ruptures or tears carry a high mortality if they are not recognized and if therapy is delayed. This is so particularly for cases of spontaneous rupture of the oesophagus which carry a higher mortality and morbidity than do cases of iatrogenic injuries. With the widespread use of fibreoptic oesophagogastroscopy, which has been accompanied by the therapeutic manipulation of strictures and tumours, the number of iatrogenic perforations has increased substantially. We report our experience with 23 oesophageal perforations or ruptures that were seen over a 15-year period. The results of both the surgical and the conservative management of such lesions were excellent and were based on the clinical condition of the patient and on the extent of the extravasation of contrast media. Our results show that not all cases of oesophageal perforations require immediate surgical exploration and that the results of surgical treatment are excellent if the diagnosis is made early.

Adolescent↗
PubMed1987

Enprostil and ranitidine: comparative efficacy and safety in patients with duodenal ulcer.

This randomised, double-blind, double-dummy, multiclinic study of duodenal ulcer healing compared the efficacy and safety of enprostil with ranitidine. The six week trial admitted 164 patients with endoscopically demonstrated duodenal ulcer. Ratings of symptoms and adverse events were collated from patients' daily diaries, and endoscopy was repeated to verify healing after four weeks and, if appropriate, after six weeks. Medication used was enprostil (35 micrograms capsule) or ranitidine hydrochloride (150 mg tablet) with matching placebos twice daily. After six weeks, 81% of patients treated with enprostil and 95% of those treated with ranitidine had healed ulcers, a statistically significant difference (p = 0.007). There were no differences between treatment groups for the number of days until the daytime ulcer pain completely ceased. Night-time ulcer pain ceased significantly earlier in the group receiving ranitidine (p = 0.019) and was less severe during the week before the last visit (p = 0.001); daytime pain for ranitidine users was also less severe (p = 0.020) during this week. Mild to moderate adverse experiences were reported by 44% of enprostil and 35% of ranitidine patients. There were no severe adverse events. In conclusion, both enprostil and ranitidine were found to be safe and effective in the treatment of duodenal ulcer. However, the ranitidine regimen used in this trial produced better results than the enprostil regimen.

Clinical Trials as Topic↗
PubMed1986

The influence of colonoscopy on the operative management of colorectal cancer.

Total colonoscopy was used in the evaluation of 85 patients with colorectal cancer, either preoperatively or within six months of surgery. Synchronous lesions (six carcinomas, 22 adenomatous polyps, one villous adenoma and nine cases of severe diverticular disease) were detected in 38 (44.7%) patients. The planned surgical procedure was altered in 10 patients (11.8%)--a more extensive resection being performed in each case. In particular, five of the six cases of synchronous cancers were located in different surgical segments. Colonoscopy is a necessary prerequisite in the evaluation of patients with colorectal cancer.

Aged↗
PubMed1986

Platelet function in patients receiving enprostil.

The effect of 14 days of treatment with enprostil (35 micrograms twice daily) or ranitidine (150 mg twice daily) on platelet function in 21 patients with duodenal ulcer was evaluated in a double-bind, randomized, parallel study. Platelet function, as determined by the results of a coagulation screen, aggregation tests, and an assay for plasma beta-thromboglobulin levels, was assessed before and after 14 days of treatment. No effect on platelet function was observed with either drug in this group of patients.

Adult↗
PubMed1981

Double-blind trial of cimetidine versus tri-potassium di-citrato bismuthate in chronic duodenal ulceration.

Thirty-seven patients with chronic duodenal ulceration were entered into an endoscopically controlled trial of cimetidine (Tagamet) versus tri-potassium di-citrato bismuthate (De-Nol). At six weeks, 83% of patients taking cimetidine showed complete ulcer healing compared with 74% of patients taking tri-potassium di-citrato bismuthate. By ten weeks, the corresponding figures were 89% and 84% respectively. Symptomatic relief was similar in both treatment groups and, despite advice to the contrary, continued smoking and alcohol consumption did not appear to adversely affect healing. Both drugs appear to be equally effective in healing chronic duodenal ulcers.

Adult↗