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Biomedical subjects

A T Cole

Publications and source records attributed to A T Cole.

At least 19 recordsLinked to original sources
PubMed1992

Ranitidine: differential effects on gastric bleeding and mucosal damage induced by aspirin.

This study investigated the influence of ranitidine on mucosal injury and gastric bleeding in 20 normal volunteers taking 600 mg aspirin q.d.s. This study was a double-blind placebo controlled crossover study comparing ranitidine, as 150 mg b.d., 300 mg q.d.s. and 600 mg b.d. with placebo. Gastric mucosal injury was assessed at unsedated endoscopy by counting haemorrhagic and non-haemorrhagic erosions; bleeding was measured in gastric washings. Aspirin alone increased mucosal injury from 0 to 11.4 erosions (mean, P < 0.01) and bleeding from 1.77 to 9.11 microliters blood/10 min (mean P < 0.001). Ranitidine prophylaxis reduced bleeding to 5.34, 3.18 and 3.47 microliters/10 min with 150 mg b.d., 300 mg q.d.s. and 600 mg b.d. respectively (overall effect of ranitidine P < 0.001) and also reduced haemorrhagic erosions though it had no effect on the total number of erosions. Ranitidine is effective at reducing aspirin-induced gastric bleeding and whilst not reducing aspirin-induced gastric erosions, it does reduce the number that appear haemorrhagic. Ranitidine may have a role in the prophylaxis of aspirin-induced gastric bleeding.

Adult↗
PubMed1992

Mechanisms of gastric and duodenal damage and protection.

By binding to the cyclooxygenase enzyme, non-steroidal, anti-inflammatory drugs (NSAIDs) inhibit synthesis of prostanoids characteristic of the cell under consideration. For the gastric mucosa, the main products are prostaglandin (PG) E2 or PGI2; for platelets the main product is thromboxane. Aspirin irreversibly acetylates the cyclooxygenase enzyme. Consequently, it has more prolonged effects, particularly in cells like platelets, which are not rapidly turned over. Prostaglandin-dependent protective actions in the stomach and duodenum which are inhibited by NSAIDs include mucous and bicarbonate secretion, surface epithelial cell hydrophobicity and mucosal blood flow. Prostaglandins are also protective of the microvasculature and can increase the flux of water from serosa to mucosa, with possible dilution of injurious substances. Abrogation of these properties renders the mucosa more vulnerable to injury. In addition, salicylates have topical irritant properties. A number of repair mechanisms, including epithelial cell division and possibly angiogenesis, are prostaglandin dependent. As a consequence of these actions, acute damage and ulcers develop more easily and ulcers heal more slowly when individuals take NSAIDs. In some cases the anti-hemostatic effects of NSAIDs may be partly instrumental, and data in model systems have shown that aspirin and possibly piroxicam can enhance intragastric bleeding separately from their effects of mucosal injury. Smoking, which predisposes to peptic ulceration, also appears to reduce mucosal prostaglandin synthesis. Other predisposing factors such as age, sex and the ulcer diathesis have little effect. Some have found Helicobacter pylori to enhance leukotriene synthesis. We have shown that NSAIDs are also associated with increased leukotriene B4 as well as reduced prostaglandin synthesis in patients taking NSAIDs long term.

Animals↗
PubMed1991

Separation of the impairment of haemostasis by aspirin from mucosal injury in the human stomach.

1. An increasing body of data suggests that the antihaemostatic as well as the ulcerogenic actions of aspirin and other non-steroidal anti-inflammatory drugs may be operative when patients present with haematemesis and melaena. 2. We therefore developed methods to allow separate evaluation of the erosive and anti-haemostatic actions of aspirin in the human gastric mucosa. Volunteer subjects took 300 mg of aspirin daily in the morning or 600 mg of aspirin four times a day for 5 days under blinded randomized conditions. Changes in spontaneous gastric microbleeding, endoscopic signs of injury, spontaneous bleeding per gastric erosion, biopsy-induced bleeding and eicosanoids were studied. 3. Both doses of aspirin significantly inhibited gastric mucosal synthesis of prostaglandin E2 and reduced the serum thromboxane concentration. Erosions developed and regressed rapidly; compared with baseline 300 mg of aspirin daily in the morning caused substantial numbers of gastric erosions to develop (mean 5.3, 95% confidence limits 2.7-10.2) but this was significantly less than that caused by 600 mg of aspirin four times a day (10.9, 7.2-16.5, P less than 0.05). The presence of erosions was associated with enhanced spontaneous bleeding, but only during aspirin administration. 4. Aspirin significantly increased bleeding induced by mucosal biopsy and was associated with significant enhancements in the rate of bleeding per gastric erosion. Bleeding rate per erosion but not biopsy-induced bleeding showed a significant dose-related increase with 600 mg of aspirin four times a day. Enteric coating reduced endoscopic signs of injury, but did not affect the impaired haemostasis caused by aspirin.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Aspirin-induced gastric mucosal damage: prevention by enteric-coating and relation to prostaglandin synthesis.

1. Gastric damage induced by low-dose aspirin and the protective effect of enteric-coating was assessed in healthy volunteers in a double-blind placebo-controlled cross-over trial using Latin square design. Each was administered placebo, plain aspirin 300 mg daily, plain aspirin 600 mg four times daily, enteric-coated aspirin 300 mg daily, or enteric-coated aspirin 600 mg four times daily for 5 days. Gastric damage was assessed endoscopically, and gastric mucosal bleeding measured. 2. Aspirin 300 mg daily and 600 mg four times daily caused significant increases in gastric injury compared with placebo. Gastric mucosal bleeding was significantly more with the high dose, with a trend towards increased gastric erosions, compared with the low dose. 3. Enteric-coating of aspirin eliminated the injury caused by low dose aspirin and substantially reduced that caused by the higher dose. 4. All dosages and formulations caused similar inhibition of gastric mucosal prostaglandin E2 synthesis. 5. Serum thromboxane levels were suppressed equally with plain and enteric-coated aspirin. 6. In this short-term study in healthy volunteers, gastric toxicity from aspirin was largely topical, independent of inhibition of prostaglandin synthesis, and could be virtually eliminated by the use of an enteric-coated preparation.

Adult↗
PubMed1977

Pheochromocytoma: recent experience with detection and management.

Our experiences spanning a ten-year period have been reviewed with regard to pheochromocytoma. During this period 1,890 metanephrine excretion levels were performed; 91 of these were elevated. An over-all incidence of 1.9 per cent false positive studies was found. Factors contributing to the false positive studies are discussed. Fourteen patients had 15 pheochromocytomas resected. The presenting features, diagnosis, localization, preoperative and operative management, as well as the results are presented.

Adolescent↗
PubMed1977

Preureteric vena cava.

Preureteric vena cava is a rare congenital anomaly usually presenting clinically with hydronephrosis and an "S or fishhook" deformity of the ureter at the third or fourth lumbar vertebrae. Unusual presentations do occur and can lead to misdiagnoses. Herein such a case originally diagnosed as a ureteropelvic junction obstruction is presented and the embryology reviewed.

Adult↗
PubMed1977

Congenital total hemihypertrophy and carcinoma of undescended testicle: a case report.

The first case of germinal cell tumor of the testis in a patient with congenital total hemihypertrophy is reported. The literature is discussed with emphasis placed on the frequent association of hemihypertrophy with oncogenesis and teratogenesis. We conclude that because of the high incidence of malignancy in the undescended testis prophylactic orchiectomy should be considered in a patient with hemihypertrophy and cryptorchidism.

Cryptorchidism↗
PubMed1977

Complications of partial cystectomy in patients with high grade bladder carcinoma.

We herein analyze the results of partial bladder resection in 61 patients with stage A transitional cell carcinoma. Staging was based on preoperative evaluation, operative findings and postoperative microscopic study of the specimen. In 54% of the patients with high grade malignancies local recurrences were noted and the patients eventually died of the disease. There were no recurrences in patients with low grade tumors. Therefore, the grade of bladder carcinoma should be considered when patients are chosen for this operation.

Carcinoma, Transitional Cell↗
PubMed1977

Large prostatic hematomas associated with carcinoma of the prostate.

Two cases are presented of large prostatic hematomas secondary to adenocarcinoma of the prostate. The similarity of these cases at examination to prostatic abscesses complicated diagnosis and delayed treatment. To avoid diagnostic error it is important to remain alert to this atypical presentation and to remember the necessity to obtain adequate biopsies.

Abscess↗
PubMed1977

Capillary hemangioma of the male urethra: case report with literature review.

The seventeenth case of hemangioma of the urethra is reported. A review of the literature supports our own experience that this growth tends to recur locally. It is our opinion that an initial wide resection should be performed. The margins of the removed lesion must be uninvolved or recurrence is almost certain.

Child↗