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Biomedical subjects

R W Busuttil

Publications and source records attributed to R W Busuttil.

At least 343 records · Page 19Linked to original sources

Pathogenesis of aortoduodenal fistula: experimental and clinical correlates.

An aortoduodenal fistula (ADF) is believed to stem from erosion of a rigid prosthesis into the fixed retroperitoneal duodenum. Experimental and clinical data do not support a mechanical etiology, but indicate that the pathogenesis is an unrecognized graft infection with pseudoaneurysm formation. A 5 cm segment of Dacron was interposed in the infrarenal aortas of 24 dogs that were divided into four groups of six animals each. In group 1 (control) the duodenum was fixed by sutures to the proximal anastomosis of the Dacron graft. At 6 weeks' follow-up, no ADFs or deaths had occurred among this group. In group 2 the duodenum was fixed to the aortoprosthetic anastomosis and the dogs received an intravenous infusion of 10(8) S. aureus; two of these dogs developed ADF (P less than 0.01). In group 3 the duodenum was incorporated as a patch on the anterior aspect of the aortoprosthetic suture line, creating a false aneurysm; three of these animals died as a result of ADF. A false aneurysm was created in group 4 dogs, as in group 3, but in addition, 10(8) S. aureus was administered intravenously; here five to six animals developed ADF. Clinical and bacteriological evidence of graft infection was present in seven of 11 patients with ADF who were seen over an 18 year period. Five had pseudoaneurysm formation at the proximal anastomosis. Operation was performed in eight patients; three had closure of the aortic leak and repair of the duodenum with omentum interposition. All resulted in recurrent fistula and delayed hemorrhage. Simple graft excision in two patients without reconstitution of peripheral circulation resulted in lower extremity gangrene. The three survivors had graft excision and axillofemoral bypass. These data suggest that the etiology of ADF is primary low-grade infection. Successful operation necessitates excision of the graft, duodenal closure, and an extraanatomical axillofemoral bypass graft.

Aged↗

The Warren shunt in treating bleeding esophageal varices.

In patients who have impaired hepatic reserve, the Warren shunt has been proposed as an effective operation because it decompresses the esophageal varices without disturbing portal perfusion of the liver. However, early reports of high operative mortality and technical difficulties have impeded acceptance of the procedure. The operation was done in a series of 17 patients. All patients in whom elective variceal decompression with a patent splenic vein was required and without clinical ascites were candidates for this operation. Follow-up ranged from 2 to 48 months. Six patients had alcoholic cirrhosis, two had primary biliary cirrhosis and seven had postnecrotic cirrhosis; in two the cause of the liver disease was unknown. Five patients were categorized as Child's class A, nine as class B and three as class C. No intraoperative or early postoperative deaths owing to hemorrhage occurred. However, there was one death two weeks postoperatively from pulmonary sepsis and one death five weeks postoperatively due to antigen-positive hepatitis. Two patients died from hepatic failure six weeks and five months after operation, respectively; in the first of these, chronic active hepatitis was diagnosed at the time of operation. In one patient hemorrhage recurred and transfusion was required. Although ascites, which eventually resolved, developed in eight patients after operation, the results in 76 percent of patients have been good without new episodes of hemorrhage or encephalopathy. We conclude that the Warren shunt is a safe and effective elective operation for the treatment of patients in whom hemorrhage from esophageal varices has occurred.

Adolescent↗

The symptoms of an amebic abscess of the liver simulating an acute surgical abdomen.

Amebic abscess of the liver has protean manifestations that often resemble causes of an acute surgical abdomen. Patients presenting at University of California, Los Angeles Hospital with acute abdominal injuries who underwent exploratory laparotomy and subsequently were found to have an amebic hepatic abscess were studied. There are various clinical symptoms of amebic hepatic abscess as well as problems of differentiating this pathologic entity from an acute surgical abdomen. Most patients with amebic hepatic abscess that mimics an acute abdomen present as acute cholecystitis or acute appendicitis. All patients recovered uneventfully once the diagnosis was made and appropriate therapy instituted. The salient features of the history, physical examination and laboratory data that can identify the amebic abscess were analyzed. The key to correct diagnosis is cognizance of the condition.

Abdomen, Acute↗

Acute appendicitis: efficacy of prophylactic preoperative antibiotics in the reduction of septic morbidity.

The course of 200 patients who recently underwent appendectomy at UCLA for acute appendicitis has been reviewed to determine the efficacy of preoperative systemic antibiotic prophylaxis in reducing septic morbidity after surgery. Among those with nonperforated appendicitis who were given gentamycin and clindamycin preoperatively, a reduction of infection rate from 10.2 to 5.3 per cent was found when compared with patients who received no antibiotics.

Adolescent↗

Chylous ascites after a Warren shunt.

A patient with intractable chylous ascites after a successful Warren shunt procedures is presented. The general incidence, etiology, pathophysiology, and treatment modalities of chylous ascites are discussed. Chylous ascites is a serious postoperative complication of the Warren shunt and should be considered in the differential diagnosis of a patient with ascites subsequent to this procedure.

Chylous Ascites↗

Possible role of cyclic nucleotides in the mechanism of the protective effect of methylprednisolone on the hypoxic rat heart.

The isolated isovolumic rat heart was used as a model of cardiac hypoxia. Force of cardiac contraction and cardiac cyclic nucleotide levels (cyclic GMP and cyclic AMP) were monitored in hearts subjected to hypoxia for 5 min and allowed to recover by reoxygenation. Hearts were obtained from both control animals and animals pretreated with methylprednisolone at 18 hr and 1 hr prior to sacrifice. Myocardial levels of cyclic GMP which were significantly (p less than 0.05) elevated above control during all periods of hypoxia were found to be lower when hearts were pretreated with methylprednisolone prior to hypoxic exposure. Hearts of animals pretreated with methylprednisolone also demonstrated better recovery during reoxygenation than did control hearts. These studies suggest that methylprednisolone may be beneficial in the prevention of myocardial failure following hypoxia via a modulation in myocardial cyclid GMP content.

Animals↗

Treatment of carcinoma of the sigmoid colon and upper rectum. A comparison of local segmental resection and left hemicolectomy.

We report a retrospective study of 107 cases of carcinoma of the sigmoid colon and upper rectum treated for primary cure at the University of California at Los Angeles Hospital between 1955 and 1970. Excluded from this analysis were patients treated by abdominoperineal resection, local excision, fulguration, or abdominoperineal pull-through procedures. Ninety-one patients were treated by local segmental resection and 16 by left hemicolectomy. Both groups were similar in regard to patient age and general health, lesion size, location, and pathological Duke's classification. Five-year survival was 70.3% after local segmental resection and 56.3% after left hemicolectomy. Hospital mortality was 1% after the former and 6.2% after the latter. Rate of recurrence after local segmental resection was 41% of that seen after left hemicolectomy, while complications were one-third as great. The present results after local segmental resection are comparable to the results reported in the literature when hemicolectomy was the procedure used. The data presented suggest that local segmental resection is an effective cancer operation for carcinoma of the sigmoid and upper rectum, and is fraught with a lesser morbidity and mortality than a radical left hemicolectomy.

Adult↗

Primary adenocarcinoma of the small intestine.

Eighteen cases of primary adenocarcinoma of the small intestine have been reviewed, which demonstrated the relative frequency of symptoms common to this disease. The clinical features, pathology, and treatment of small bowel adenocarcinoma have been presented and the literature reviewed.

Adenocarcinoma↗

Changes in cyclic nucleotide levels and contractile force in the isolated hypoxic rat heart during perfusion with glucagon.

Isolated rat hearts were perfused with hormonal concentrations of glucagon during a hypoxic perfusion to determine whether it would enhance recovery after reoxygenation. Rat hearts were divided into two groups: (1) those perfused with glucose-free Tyrode's solution and (2) those perfused with Tyrode's solution containing glucose. During 3 minutes of exposure to hypoxia both untreated hearts and hearts perfused with glucagon demonstrated a decrease in contractile force to 10-20% of control. When glucose was present in the perfusion medium, cardiac performance was better during both the periods of hypoxia and reoxygenation. During reoxygenation, recovery of contractile force was significantly better (P less than 0.05) in glucagon-perfused hearts than in untreated hearts; this improved recovery occurred regardless of whether glucose was included in the medium. The enhanced recovery of the glucagon-perfused hearts was associated with decreases in myocardial levels of guanosine, 3',5'-monophosphate (cyclic GMP) both during the periods of hypoxia and reoxygenation. At the end of the hypoxic period, cyclic GMP levels in the glucagon-perfused hearts were 20-64% of the levels in untreated hearts. Similarly, after 5 minutes of reoxygenation cyclic GMP levels in the glucagon-perfused hearts were 21% of the levels in the untreated hearts. The effect of glucagon on adenosine 3',5'-monophosphate (cyclic AMP) concentrations in untreated hearts and in hearts receiving glucagon was not significantly different either after 3 minutes of hypoxia or during reoxygenation. The rate of anaerobic glycolysis after 3 minutes of hypoxia was higher in untreated hearts than in glucagon-perfused hearts, as determined by the lactate content of coronary perfusates. These studies suggest that hormonal concentrations of glucagon exert a protective effect on the hypoxic rat heart which involves a modulation of cardiac cyclic GMP accumulation.

Animals↗

Effects of glucagon on cardiac cyclic nucleotides in the hypoxic heart.

Isolated rat hearts were perfused with a subinotropic concentration of glucagon during an hypoxic perfusion to determine whether glucagon would enhance recovery upon reoxygenation. Rat hearts were divided into two groups: 1) those perfused with glucose-free Tyrode's solution and 2) those perfused with Tyrode's solution containing glucose. During 3 min of hypoxic exposure, untreated hearts and hearts perfused with glucagon both demonstrated a dramatic decrease in contractile force regardless of whether glucose was included in the medium. However, when glucose was present in the perfusion medium cardiac performance was better during both hypoxia and the period of reoxygenation. Furthermore, during reoxygenation, the recovery of contractile force was significantly greater in glucagon-perfused hearts than in controls. Cardiac levels of cyclic AMP and cyclic GMP were monitored at various periods of hypoxic exposure to test the existence of a correlation between the concentrations of these cyclic nucleotides and cardiac performance. During reoxygenation of untreated hearts, the hearts perfused with glucose-free medium attained 45-50 percent of the contractile force seen in glucagon-treated hearts. This enhanced recovery in the glucagon-treated hearts was associated with decreases in cyclic GMP levels at the end of the hypoxic period. At this time, the cyclic GMP levels in the glucagon-treated hearts were only 25-55 percent of the levels seen in untreated hearts that were also exposed to hypoxia. The effect of glucagon on cyclic AMP content in untreated hearts and in hearts receiving glucagon was not significantly different at 3 min of hypoxia. These studies suggest that subinotropic concentrations of glucagon exert a protective effect on the hypoxic rat heart that is not related to the direct inotropic properties of this hormone but which may involve a modulation in cardiac cyclic GMP availability.

Animals↗

The use of Mersilene mesh in repair of abdominal wall hernias: a clinical and experimental study.

Use of synthetic materials in herniplasty has been a controversial issue. In order to determine the influence of Mersilene mesh on the strength of healing abdominal wounds and its effectiveness in repair of hernia, experimental and clinical studies were undertaken. Experimental study included 175 male rats divided into three groups subjected to either: 1) an incision made only through the skin and closed with 3-0 silk sutures; 2) a 2.5 cm midline incision through the musculature and peritoneum closed with 2-0 Mersilene suture; or 3) the same procedure as group 2 with the addition of a Mersilene mesh onlay graft. Bursting strength of abdominal wounds as determined in all groups at intervals. Wounds of the group treated with the mesh exhibited significantly greater (P less than 0.01) bursting strength. Clinical trial consisted of 100 consecutive adult patients in which an onlay graft of Mersilene mesh was used in the hernioplasty. Mesh was used as an adjunct in patients with: 1) large ventral hernias; 2) direct hernias resulting from severely attenuated transversialis fascia; 3) indirect hernias associated with a large internal ring and a weak posterior inguinal wall; or 4) combined direct and indirect hernias. All were followed for a minimum of one year to determine the incidence of complication and rate of recurrence. This study suggests that: 1) Mersilene mesh increases the strength of healing abdominal wounds in rats; and 2) repair of large hernias with Mersilene mesh results in an acceptable morbidity and a lowered rate of recurrence.

Abdominal Muscles↗

Protective effect of methylprednisolone on the heart during ischemic arrest.

Although corticosteroids have been shown to stabilize lysosomal membranes and prevent release of hydrolytic enzymes, the mechanism of membrane stabilization remains obscure. The few reports regarding the use of steroids in myocardial ischemia have been conflicting. This study was undertaken to determine if a pharmacologic dose of the glucocorticoid methylprednisolone would protect the heart during ischemic cardiac arrest. A randomized double-blind study was performed in 25 dogs. Biochemical and hemodynamic parameters were assessed during and after cardiopulmonary bypass and after 30 minutes of ischemic cardiac arrest. Animals were divided into two groups. Group I served as controls and consisted of dogs injected intravenously with the vehicle of methylprednisolone 18 hours and 1 hour prior to experiment. Group II comprised dogs injected with methylprednisolone, 30 mg. per kilogram, IV, at the same time periods. Blood pH, gases, and electrolytes were measured; aortic, left atrial, and left ventricular pressures were monitored; the first derivative of the left ventricular pressure (dp/dt max.) was also determined. Arterial and coronary sinus blood samples were assayed for lactate levels and activity of the lysosomal enzyme, beta-glucuronidase. Left ventricular muscle was assayed for the nucleotides cyclic adenosine 3',5' monophosphate (AMP) and cyclic guanosine 3',5' monophosphate (GMP). Following restoration of coronary flow, mean aortic and left ventricular systolic pressures and left ventricular contractility as determined by dp/dt max. and dp/dt max./IP were depressed in both groups as expected but were significantly higher in Group II than in Group I (p less than 0.05). An increase in levels of both cyclic nucleotides occurred in each group during ischemia, but this increase in cyclic GMP was significantly greater in Group I (p less than 0.05). beta-glucuronidase activity and myocardial potassium loss as determined in coronary sinus blood were both significantly greater in Group I than in Group II (p less than 0.05). Results of this study demonstrate that pretreatment with a pharmacologic dose of methylprednisolone significantly enhances cardiac recovery after ischemia. Lysosomal membrane stability and modulation of cyclic GMP levels may be critical determinants in the mechanism of cardiac ischemia.

Animals↗

Opposing regulatory influences of cyclic guanosine monophosphate and cyclic adenosine monophosphate in the control of cardiac muscle contraction.

The effects of acetylcholine chloride (ACh) and isoproterenol (Iso) on myocardial levels of guanosine 3', 5'-monophosphate (cyclic GMP) and adenosine 3', 5'-monophosphate (cyclic AMP) and on force of contraction were studied in elelctrically driven isolated rabbit atria. Incubation of atria with Tyrode's solution containing ACh (5 x 10(-7) M) produced significant decreases in contractile force that were associated with significant elevations in atrial cyclic GMP levels. Atrial levels of cyclic AMP were significantly lowered at 15 sec after the addition of ACh but were only slightly lowered at earlier time intervals. The effects of acetylcholine on force of contraction and on cyclic nucleotide levels were prevented with atropine (1 x 10(-7) M). The addition of Iso (1 x 10(-7)-M) to isolated atria produced significant increases in contractile force that were associated with significant elevations in effects of Iso on force of contraction and on cyclic nucleotide levels were prevented with practolol (1 x 10(-5) M). The increases in atrial cyclic GMP and cyclic AMP levels following addition of ACh and Iso, respectively, precede the changes in contractile force. These data support our hypothesis that cyclic AMP and cyclic GMP exert oppositional effects on cardiac contrctility.

Acetylcholine↗