Search PubMed⌕ Search

Biomedical subjects

G R Mason

Publications and source records attributed to G R Mason.

At least 91 records · Page 5Linked to original sources
PubMed1982

A model of experimental isolation perfusion using cis-platinum.

An animal model has been devised to investigate effects of hyperthermia and chemotherapeutic agents on normal and neoplastic tissue. This model uses the rabbit as the experimental animal and will permit the passage of the transplantable VX-2 carcinoma. The technique described parallels clinical isolation-perfusion and utilizes cis-platinum as the chemotherapeutic agent. This model has proven to be reliable and consistent in achieving tissue temperature at therapeutic ranges and has documented the safety of using cis-platinum in this mode of therapy.

Animals↗
PubMed1982

Treatment of mixed-dust pneumoconiosis with whole lung lavage.

A patient with silicosis and progressive dyspnea on exertion is described in whom open lung biopsy revealed active chronic inflammation with many macrophages filling alveolar spaces. Because of the extensive involvement by the disease of small air spaces, bilateral whole lung lavage was performed. The lung lavage effluent was striking in its blackish brown color. It was composed predominantly of macrophages containing silica, silicates, and graphite. Particles in the tissue and lavage were analyzed using scanning electron microscopy and energy dispersive X-ray analysis. The dry weight of the material removed was approximately 25 g, of which an estimated 135 mg was silica. The procedure resulted in immediate symptomatic improvement in the patient. Although his pulmonary function did not change significantly, it is hoped that removal of this material will improve his long-term prognosis.

Biopsy↗
PubMed1982

Results of surgical management of hemorrhagic gastritis in patients with gastroesophageal varices.

The records of 13 patients with gastroesophageal varices, operated upon for the prevention or control of hemorrhage from gastritis, were reviewed. Bleeding was controlled postoperatively in all nine patients in whom the operations included variceal decompression, while the remainder had recurrent or continuing hemorrhage, p = 0.0013. The over-all operative mortality was 69 per cent, reflecting excessive blood loss preoperatively in the 11 actively bleeding patients. It is concluded that hemorrhagic gastritis in patients with varices should be viewed as portal hypertensive bleeding and that the basis for therapy must be the early institution of measures which effect a reduction of portal pressure.

Esophageal and Gastric Varices↗
PubMed1982

Prognostic indices in the treatment of acute diverticulitis: a retrospective study.

A review of patients with acute diverticulitis admitted to the University of Maryland Hospital over the past ten years revealed a high frequency of surgical intervention. In addition to the usual indications for surgery (obstruction, perforation, and fistula), we found persistent mass combined with other clinical indices, such as fever, leukocytosis, tachycardia, or recurrence required surgical intervention. Medical therapy (i.e., intravenous hydration, antibiotics, diet, nasogastric suction, etc.) varied with the clinical presentation. Only 43 per cent of the medically treated patients received antibiotics. If the bowel can be adequately prepared, a one-stage operation may be possible. Otherwise more stages may be necessary. A prognostic index has been devised for acute diverticulitis for the evaluation of medical vs. surgical therapy. The higher the index, the more extensive the procedure that will be used. Our study supports the general usefulness of a Hartman (two-stage) procedure for those patients requiring surgery.

Acute Disease↗
PubMed1981

Gastric and pyloric motor response to sympathetic nerve stimulation after chemical sympathectomy.

This study evaluated the effect of electrical stimulation of the greater splanchnic nerve on gastric and gastroduodenal motility in 6-hydroxydopamine (6-OHDA)-pretreated anesthetized dogs. Biopsies from the stomach, pylorus and duodenum were obtained and analyzed by catecholamine fluorescence microscopy. Degeneration of adrenergic terminals in Auerbach's plexus was complete at 1 week. The majority of stimulations in control dogs or dogs treated with 6--OHDA produced contractions in the gastric body, antrum, and pylorus and relaxation of inhibition in the duodenum. The excitatory motor responses in the gastric body, antrum and pylorus were unaffected by the administration of hexamethonium. Following atropine administration, contractions due to splanchnic nerve stimulation virtually were abolished in the antrum, pylorus and duodenum and were reduced in number in the gastric body. Relaxation and inhibition were no longer observed in the duodenum after atropine. The greater splanchnic nerve appears to contain both excitatory are inhibitory cholinergic pathways to the musculature of the stomach, pylorus, and duodenum.

Animals↗
PubMed1981

Computed tomography for localization of parathyroid adenomas.

Fourteen consecutive patients with the clinical diagnosis of primary hyperparathyroidism had computed tomography (CT) preoperatively to evaluate the use of CT in localizing parathyroid adenomas. The patients were scanned from above the level of the thyroid cartilage to the bifurcation of the trachea. Computed tomography correctly identified, prospectively, the site of the adenoma in 7 of 14 patients, including one adenoma that was ectopic in location. Nine of these patients also had barium esophagrams, and this study was accurate in only three of the nine. Our study suggests that CT may be beneficial in the preoperative localization of parathyroid adenomas, particularly those in ectopic locations.

Adenoma↗
PubMed1981

Mechanism of propagation of canine migrating motor complex--a reappraisal.

This study quantitatively evaluated the characteristics of the aboral propagation of the canine migrating motor complex (MMC). Five conscious dogs were implanted with extraluminal force transducers along the small intestine. After constructing a 30-cm Thirty-Vella loop of jejunum, 56 of 91 activity fronts were outside the tolerance limits for propagation from the proximal intestine to the loop established in the same dogs before operation. Similarly, 44 of 109 activity fronts were outside the tolerance limits for propagation from the loop to the distal intestine. After surgery, the propagation time from the proximal jejunum to the loop was significantly increased, and activity fronts were observed to originate in the loop and in the intestine distal to the anastomosis. Our study indicates that the hypothesis that extrinsic nerves alone control the migration of the MMC is incomplete. We suggest that the extrinsic and the intrinsic innervation of the gastrointestinal tract are both required for the precise pattern of the migration of the MMC.

Action Potentials↗
PubMed1981

Pyloric motor response to sympathetic nerve stimulation in dogs.

Through this study we evaluated the effect of electrical stimulation of the greater splanchnic nerve on gastroduodenal motility in anesthetized dogs. The majority of stimulations (at a frequency of 10 Hz for 5 msec at a strength of 10V for a train of 10 sec) produced contractions in the gastric antrum and pylorus and relaxation in the duodenum. The antral, pyloric, and duodenal motor responses were unaffected by cervical vagosympathectomy, thoracic vagotomy, and adrenalectomy. Administration of phentolamine, propranolol, or hexamethonium and pretreatment with reserpine failed to affect the contractile gastroduodenal motor response. The inhibitory motor response in the duodenum was also unaffected by these surgical procedures and administration of drugs. After atropine administration, contractions induced by splanchnic nerve stimulation were abolished in the pylorus, as well as in the antrum and duodenum. Tetrodotoxin also abolished the gastroduodenal motor response. The greater splanchnic nerve contains an excitatory cholinergic pathway to the musculature of the pylorus.

Animals↗
PubMed1980

Nonfunctioning retroperitoneal paragangliomas.

Nonfunctioning paragangliomas of the retroperitoneum are extremely rare tumors. As of this report, 30 cases are known from published data. Characteristics of these tumors and diagnostic techniques are herein described. Approximately 20 percent of these lesions are considered malignant. Surgical resection is the treatment of choice once the diagnosis is made.

Adult↗
PubMed1979

Aortocystoduodenal fistula: rare complication of pancreatic pseudocyst.

An upper gastrointestinal tract hemorrhage resulting from an aortocystoduodenal fistula developed in a patient with a pancreatic pseudocyst. The fistula was exposed through a duodenotomy, necrotic material was debrided from the pseudocyst and the aortic wall, the aortic defect was closed primarily, and the pseudocyst was drained through a cystoduodenostomy. The case is discussed as a rare hemorrhagic complication of pancreatic pseudocysts and as an illustration that under certain circumstances of infection in areas where aortic bypass can be difficult to perform, primary vascular repair can be a successful method of managing aortoenteric fistulas.

Aortic Diseases↗
PubMed1979

Neural control of the canine pylorus.

After atropine administration the anesthetized dog exhibits significant spontaneous pyloric contractile activity and an inhibition-relaxation response upon electrical vagal stimulation. This inhibition-relaxation response was completely blocked by tetrodotoxin administration and by transection of the intraabdominal vagal nerves. In addition, tetrodotoxin administration caused a dramatic increase in spontaneous pyloric motor activity. The histaminergic receptor antagonists diphenhydramine and cimetidine did not block the inhibition-relaxation response. The octapeptide of cholecystokinin (CCK-OP) caused a dose-dependent increase in antral and pyloric motor activity which was significantly decreased by atropine administration. Therefore, histamine and CCK do not appear to play a significant role in the vagally mediated inhibition-relaxation response of the canine pylorus or in the atropine-resistant spontaneous pyloric motor activity.

Animals↗