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Biomedical subjects

R M Stone

Publications and source records attributed to R M Stone.

At least 73 records · Page 4Linked to original sources
PubMed1985

Further report of a prospective randomized trial comparing distal splenorenal shunt with end-to-side portacaval shunt. An analysis of encephalopathy, survival, and quality of life.

We electively compared the distal splenorenal ("selective") shunt with the end-to-side portacaval shunt in 80 prospectively randomized patients with variceal bleeding. Selective shunts required more operative time (3.9 vs. 2.8 h) and blood replacement (4.6 vs. 2.5 U) and postoperative mortality was slightly higher (5 of 38 selective vs. 0 of 40 portacaval). Postoperative complication rates were similar. After 65-mo mean follow-up, both shunts have protected well against late gastrointestinal bleeding (5 selective, 4 portacaval episodes). However, after selective shunts, spontaneous encephalopathy occurred less often (23% vs. 40% of patients), was severe in fewer patients (12% vs. 33%), and precipitated fewer hospital admissions (6 admissions in 4 selective patients vs. 26 admissions in 13 portacaval patients). Furthermore, selective shunt patients remained longer without functional disability (83% vs. 70% of postoperative patient months). Long-term survival was not significantly different in the two groups (5-yr survival: selective 51%, portacaval 56%).

Adult↗
PubMed1985

Intraocular lens design for the neodymium:YAG laser.

Phacoemulsification was performed on both lenses of 24 rabbits. One eye received a lens implant with a convex-plano optic; the fellow eye received an implant with a convex-concave optic which separated the posterior surface of the implant from the posterior capsule by 0.2 mm, 0.3 mm, or 0.4 mm. A YAG laser capsulotomy was performed on all eyes immediately following surgery and an assessment of both microscopic and macroscopic YAG-induced lens damage was made. The meniscus optics with their capsule-implant separation showed significantly less YAG-induced damage than their convex-plano counterparts without this separation. Increasing the amount of capsule-implant separation beyond 0.2 mm did not enhance the degree of protection from YAG-induced damage.

Animals↗
PubMed1983

Evaluation of Pseudomonas aeruginosa exotoxin A and elastase as virulence factors in acute lung infection.

Acute Pseudomonas aeruginosa pneumonia was established in guinea pigs by intratracheal instillation of bacteria. Challenge strains included PAO-1, a strain known to produce exotoxin A, alkaline protease, and elastase, and several PAO-1 mutants deficient in either biologically active exotoxin A or elastase production. Survival, intrapulmonary killing of bacteria, and blood cultures were compared among the groups. Strains of P. aeruginosa deficient in active elastase production appeared to be less virulent than the parent strain and were more easily cleared from the lung. Opposite results were obtained for the exotoxin A-deficient mutants. These data suggest that elastase, but not exotoxin A, was an important virulence factor during acute pneumonia due to P. aeruginosa.

ADP Ribose Transferases↗
PubMed1982

A modified Sugiura procedure.

The Sugiura procedure for esophageal varices combines splenectomy with esophagogastric devascularization, which destroys the intraesophageal portacaval shunt but preserves periesophageal portacaval shunts. We have modified the total vagotomy and pyloroplasty and sutured esophageal anastomosis of the original operation. A single left thoracoabdominal incision is used. Esophagogastric devascularization is performed without dividing the main vagus trunks; only a proximal gastric vagotomy is done, thereby avoiding a pyloroplasty. The esophageal transection and reanastomosis are performed with the circular End-to-End Anastomosis stapler and protected with a loose-fundal wrap. Fifteen of 20 patients have had good to excellent results, with rapid recovery and no recurrent esophagogastric bleeding or any hepatic encephalopathy in follow-up of two months to two years. Four patients, who were bleeding massively at the time of operation and who were in Child's class C with gross ascites, muscle wasting, ad coagulopathy, died in the postoperative period. Conceptually, the operation is original and exciting because it preserves hepatic blood flow and the beneficial periesophageal shunt, while destroying the harmful intraesophageal shunt. Our early experience encourages us to continue using this operation, except in those patients who bleed massively and are in Child's C, end-stage, class.

Esophageal and Gastric Varices↗
PubMed1981

Heterotopic gastric tissue of the bile duct.

A unique heterotopia of the main hepatic duct causing episodic jaundice in a young man is described. The clinical presentation, radiologic diagnosis, and histologic findings are presented, as well as the possible embryologic etiology. Extensive review of the literature indicates that this case is unique. Although heterotopic gastric tissue previously has been found in the gallbladder, none has been reported in the extrahepatic bile ducts.

Adult↗
PubMed1980

A prospective randomized trial of the selective distal splenorenal shunt.

Distal splenorenal shunt has been compared in a prospective randomized way with end-to-side portacaval shunt in patients who have survived a major hemorrhage from esophageal varices. The operative mortality was higher after the elective shunt than after the portacaval shunt. However, most of these deaths occurred in the early phases of the study. Postoperative encephalopathy was significantly lower after the selective shunt than after the portacaval shunt. Follow-up studies to date show no significant difference in late survival.

Adult↗
PubMed1980

Emergency portacaval shunting in Jehovah's Witnesses.

Major surgical procedures in Jehovah's Witnesses are complicated by their refusal to accept blood transfusion. This problem is accentuated in Jehovah's Witnesses with major gastrointestinal bleeding. The authors present two cases of successful surgical management of upper gastrointestinal bleeding in Jehovah's Witnesses who had bleeding esophageal varices. A short "skin to skin" time and minimal blood loss were important factors in the successful outcome. Treatment of these patients without blood transfusion suggests that less blood might be needed in more routine surgical procedures.

Blood Transfusion↗
PubMed1980

Continent reservoir ileostomy: 1. Early experience and evolution of the surgical technique.

A continent Kock ileostomy was constructed in 17 patients with histologically proven ulcerative colitis; in 11 a conventional ileostomy was converted to a Kock ileostomy and in 4 the Kock ileostomy was carried out in conjunction with proctocolectomy. There were no operative deaths. All patients are completely continent with regard to flatus and stool. No patient requires an external appliance and all agree that the quality of their lives has greatly improved. However, 10 patients (59%) required at least one additional surgical procedure for early or late complications, the most frequent of which were intestinal obstruction and valve slipping. In an attempt to reduce morbidity, several technical modifications were made. The preliminary results of the modified techniques used in 17 patients are described. The benefits of the continent ileostomy are substantial despite the high initial morbidity. The authors recommend the use of the continent ileostomy in selected patients.

Adult↗
PubMed1979

Comparison of antibiotic regimens for treatment of experimental pneumonia due to Pseudomonas.

The high mortality associated with pneumonia due to Pseudomonas aeruginosa prompted a comparative trial of several currently available antibiotic regimens for this infection in a guinea pig model. Normal guinea pigs receiving an intratracheal challenge of 10(8) colony-forming units of Pseudomonas routinely died within 3-48 hr when treated with saline injections. Treatment with carbenicillin or ticarcillin did not affect this uniformly fatal outcome. Groups of animals treated with gentamicin or tobramycin had survival rates of 39% and 67%, respectively. The addition of either carbenicillin or ticarcillin to an aminoglycoside failed to enhance further the survival rates or durations of survival after infection. These survival data were supported by studies showing superior clearance of viable Pseudomonas from lung tissues in aminoglycoside-treated animals chosen at random for sacrifice 3 hr after infection. Thus, in animals experimentally challenged with P. aeruginosa to cause pneumonia and in which only a single isolate of Pseudomonas was evaluated, protection from pulmonary infection was best provided by an aminoglycoside rather than by a beta-lactam antibiotic.

Aminoglycosides↗
PubMed1979

Thrombosis of the portal vein following distal splenorenal shunt.

Portal vein thrombosis with a patent shunt is a distinct clinical entity which can follow selective distal splenorenal shunt and should be looked for in patients in whom ascites and abdominal pain develop postoperatively. Possible mechanisms include an increase in blood viscosity and a decrease in portal flow which may be aggravated by inadequate devascularization.

Adult↗
PubMed1979

Phenacetin concentrations in portal and hepatic venous blood in man.

After intra-gastric or intra-duodenal administration of phenacetin (200 mg in solution), concentrations of phenacetin and its 0-dealkylated metabolite, acetaminophen, in portal and hepatic veins and in peripheral blood were monitored. A sharp increase in the portal concentration of phenacetin indicated rapid absorption. The concentration ratio of acetaminophen to phenacetin in early portal blood was 0.01--0.11 and lower than the ratio in hepatic vein. The hepatic extraction ratio of phenacetin was calculated to be 0.59--0.78. It is concluded that 0-dealkylation occurs mainly in the liver and only to a limited extent in the gastrointestinal wall.

Acetaminophen↗
PubMed1978

Selection of operation in patients with bleeding esophageal varices.

The results of surgical treatment of bleeding esophageal varices over an 8-year period in 155 patients are reviewed. Primary treatment of bleeding was conservative, with intravenous administration of vasopressin and balloon tamponade. Emergency operations were carried out after 48 hours in persons with persistent bleeding who were surgical candidates. Operative mortality was higher in this group (40%) than in those undergoing elective or urgent operations (each 10%). Postoperative encephalopathy occurred in 35% of patients and was correlated closely to late death after establishment of a shunt. The mesocaval shunt is no better than the portacaval but appears to be a good alternative in an emergency. In a controlled trial the distal splenorenal shunt was found to be associated with a lower rate of postoperative encephalopathy than the portacaval shunt, but thus far the long-term survival rates have not differed.

Blood Vessel Prosthesis↗
PubMed1978

Massive lower gastrointestinal bleeding: an unusual complication of Crohn's disease.

Massive rectal bleeding may complicate Crohn's disease at any stage and tends to be persistent. Limited experience gained with this complication supports the use of selective agiography followed by conservative resection as the management of choice. Results of experimental studies suggest that selective infusion of vasopressors may be safely attempted when hemorrhage complicates Crohn's disease in its early stages but is probably too hazardous in cases in which the disease is more advanced.

Adult↗
PubMed1977

Metabolism of flurazepam by the small intestine.

The metabolism of flurazepam-5-14C has been studied in man following catheterization of the portal and hepatic veins. Flurazepam was administered through a tube into the stomach in one patient and into the duodenum in two patients. Thin-layer chromatographs of portal vein blood showed that there was a rapid and early appearance of metabolites of flurazepam consistent with the metabolism of the flurazepam by the intestinal mucosa and at times when the concentrations in the hepatic vein and peripheral blood were very much lower than those in the portal vein. The major metabolites identified in portal vein blood were the mono- and didesetyl metabolies of flurazepam. Considerable hepatic uptake of flurazepam and its metabolites occurred, as evidenced by the lower concentrations of the parent compound and metabolites in the hepatic vein. Thus, "first-pass" metabolism of flurazepam following oral administration occurs in the small bowel mucosa of man as well as in the liver.

Adult↗