Effect of atropine on meal-stimulated gastrin and gastric inhibitory polypeptide (GIP) release.

The effect of atropine on meal-stimulated gastric inhibitory polypeptide (GIP) and gastrin release was studied in 5 purebred foxhounds and compared with control studies done in the same animals given a meal without atropine, peak incremental serum gastrin occurred between 5 and 15 min after the meal whereas the greatest increment in serum GIP occurred 60 min postcibal. Atropine had no effect on basal concentrations of gastrin or GIP. However, when atropine was given before feeding serum gastrin concentrations from 75 to 120 min postcibal were significantly higher (P less than 0.04) than after the meal alone. The normal meal-stimulated rise in serum GIP was almost completely inhibited by atropine. We conclude that: 1) the rise in serum gastrin adter a meal preceeds the rise in serum GIP; 2) atropine potentiates the late gastrin response while suppressing the increase in serum GIP after a meal; and 3) the mechanism by which atropine potentiates gastrin release may be related to its suppressive effects on intestinal inhibitors of gastrin secretion, such as GIP.

Adverse cardiodynamic effects of vasopressin not avoided by selective intra-arterial administration.

In this study, lysine-vasopressin, administered either as a continuous, intravenous infusion (1 unit/kh/hour) or as a selective infusion into the superior mesenteric artery (0.2 unit/minute), produced equal (25%), significant (p less than 0.05), and sustained (60 minute) reductions in portal pressure. Compared to intravenous administration, selective intra-arterial infusion of vasopressin resulted in similar reductions incardiac output (38%), myocardial contractility (23%), and coronary flow (53%). Since these adverse cardiodynamic effects were not avoided by selective intra-arterial infusion, it would appear that administration of vasopressin as a continuous infusion through a peripheral vein remains the most rapid and practical method of administering the drug.

Biofragmentable bowel anastomosis ring: comparative efficacy studies in dogs.

Three studies were conducted in a total of 178 dogs to determine the efficacy of a biofragmentable bowel anastomosis ring (BAR) composed of polyglycolic acid and 12.5% barium sulfate. Wound strength and healing of BAR, suture, and staple colonic anastomoses were compared for intervals of up to 1 year. The effect of systemic steroid treatment and BAR size on anastomotic wound strength and healing was also studied. The BARs fragmented at a mean time of 15.06 days postoperatively and were passed in the feces without injury. Wound strength was determined by measurements of the pressure required to burst the anastomosed colonic segment and measurements of the tension required to break 10 mm wide longitudinal strips of the anastomosed segment. The studies demonstrated that wound strength had progressed to a point where continued mechanical support (with sutures or staples) was no longer required by 14 days in both nontreated and steroid-treated dogs. Gross healing evaluations at 21 days and beyond showed no differences due to anastomotic method. Microscopic evaluations suggested that residual granulation tissue was less at the sites of BAR asastomoses than at sites of suture or staple anastomoses at the 1-year interval, suggesting that healing may be better with BAR than with standard methods of colon anastomosis.

Observations on fifty distal splenorenal shunts.

Fifty patients underwent conventional distal splenorenal shunts for bleeding esophageal varices. Five patient died within 30 days, giving an operative mortality of 10%. Three patients were lost of follow-up, but 47 patients were evaluated. Twelve patients died, 11 of liver failure, with more than half of the deaths occurring with 1 year, three fourths within 2 years, and all within 3 years after operation. Eleven patients rebled, and seven of these were among those who died. Sixteen patients had ascites prior to operation, but all responded to aggressive medical therapy. Twenty-two patients were available for study 2 or more years following operation. Eighteen (82%) are well with no encephalopathy, although the remaining four (18%) have had transient episodes of encephalopathy. Sixteen of the 18 patients judge their lifestyles to be productive. If the patient survived 24 months or longer, he had a four in five chance of living a normal life.

A review of one hundred forty-seven popliteal aneurysms with long-term follow-up.

A 20-year experience with a collected series of 147 popliteal aneurysm in 87 patients is reviewed; there were 84 male patients. Ages ranged from 42 to 90 years with a median age of 60.2. Bilateral aneurysms were found in 60 patients (68%). Ninety-eight extremities presented with symptoms, whereas 94 aneurysms had one or more preoperative complications. Sixty-six (45%) were thrombosed, 34 (23%) had embolized, and four (3%) had ruptured. Associated aneurysms were found in 55% of the total group and in 68% of those with bilateral popliteal aneurysms. Forty percent of all patients had abdominal aortic aneurysms, whereas 34% had femoral aneurysms and 25% had iliac aneurysms. Therapy included bypass grafting (99), observations (26), primary amputation (12), sympathectomy (3), and exploration only (7). In 32 limbs, grafts became occluded during the follow-up period. All except one of the occluded grafts were in patients with preoperative symptoms related to the aneurysm, and all but one primary form of therapy and 22 as a secondary procedure. All were associated with preoperative vascular ischemia or a complicated aneurysm. Complete, detailed, long-term follow-up of 1 to 14 years is reported for 65 patients. The overall follow-up averaged 44 months. Death rates were shown by life-table analysis to be significantly greater than rates among the general population. Complications of aneurysms were very common (64%) and when the occurred, 36% ended in amputation. Therefore, elective replacement of the aneurysm at the time of diagnosis is recommended.

Determination of viability of ischemic intestine by Doppler ultrasound.

Doppler ultrasound was used to determine the viability of ischemic small intestine and to select the optimum point for resection of nonviable bowel. Twenty ischemic segments of small intestine were produced in dogs by ligating the vascular supply. The Doppler ultrasound probe then was used to determine the last point of arterial flow within the bowel wall. The dogs were reexplored after 24 hours. Histological examination of full-thickness biopsies showed the intestine to be normal in all 20 segments at the last audible Doppler signal, and in 19 of the 20 segments at 1 cm distal to the last signal. Progressive degrees of necrosis were observed at 2 and 3 cm distal to the last signal. Twenty-five segments of ischemic intestine were resected in baboons. All resections performed at the last Doppler signal or 1 cm distal to it were normal 1 month later. Of 15 resections performed at 2, 3, and 4 cm distal to the last signal, 10 showed evidence of stricture or anastomotic disruption. Doppler ultrasound is a reliable method for determining the viability of ischemic intestine and for selecting the optimum point for resection of nonviable bowel.

Apparatus for long-term ventricular access in the awake canine.

An apparatus is described that permits lateral ventricular cerebrospinal fluid (CSF) to be sampled or an infusion to be performed into the ventricular system in the awake canine. The device has been used in 25 dogs. CSF was sampled, and experiments involving infusions into the lateral ventricle were performed over a 6- to 24-mo period. The maximum frequency of ventricular cannulation using the apparatus was once per week. Complications occurred in 10 dogs, all of which were successfully treated, permitting experiments to continue. Three fatal complications included meningitis in one animal at 24 mo and seizures in two animals, causing death at 12 and 18 mo. Administration of peptides, bombesin, and somatostatin into the ventricular system was followed by prompt rises in bombesin and somatostatin radioimmunoactivity in the CSF. There were no parallel increases of these peptides in the peripheral blood levels up to 2 h after infusion. Peptides of this molecular weight infused with this apparatus do not seem to leak into peripheral blood. The apparatus permits repeated ventricular cannulation in the awake canine for sampling of CSF and administration of biological substances to determine specific central nervous system action.

Primary duodenal tumors: a diagnostic and therapeutic dilemma.

The case records of ten patients with benign, three with endocrine, and 19 with malignant duodenal tumors were reviewed. Patients with benign tumors had episodes of bleeding that were recurrent in a number of cases. The endocrine tumors were all gastrinomas; patients had ulcer diathesis associated with the Zollinger-Ellison syndrome. All malignant tumors were symptomatic, with chronic gastrointestinal blood loss or duodenal obstruction. All benign tumors were demonstrated preoperatively, but only ten of 19 malignant tumors were confirmed preoperatively. The data suggest that duodenal tumors masquerade as more common diseases and as a result, their diagnosis and treatment are delayed inordinately. Awareness of this problem is encouraged, and a more aggressive diagnostic effort in selected patients, including fiberoptic endoscopy, is suggested.

Total proctocolectomy and ileostomy: procedure of choice for acute toxic megacolon.

Of 42 critically ill patients with toxic megacolon, 31 required emergency surgery, and 11 were treated without operation. Of the 11 patients treated by medical measures alone, there were two deaths (18%): one early, secondary to undiagnosed colonic perforation, and one late death from recurrent ulcerative colitis. Nine of ten survivors (90%) experienced continued morbidity, and five (50%) required subsequent elective surgery. Thirty-one patients required emergency operation for failure of medical treatment (19), colonic perforation (ten), and uncontrolled hemorrhage (two). Early and late morbidity was 74% (two-thirds occurring after subtotal colectomy and ileostomy). Surgical mortality was 19% (8% over the last ten years).

Prevention of early failure of stapled gastric partitions in treatment of morbid obesity.

Clinical observations and data obtained in animal experiments indicate that the gastric partition is most susceptible to the stresses of solid food boluses between the second and sixth postoperative weeks, predisposing the operation to early failure. Tensiometer studies indicate that by the sixth to the eighth postoperative week, the staple line is as strong as uninjured stomach. Liquid diet restriction for eight weeks after gastric partitioning reduces the incidence of early operative failure. Until safe and effective methods of increasing staple line strength are established, all patients having gastric partitioning should be restricted to a liquid diet for eight weeks after operation.

Insulin-induced attenuation of glucose-stimulated gastric inhibitory polypeptide secretion.

Administration of exogenous insulin before and after intraduodenal glucose results in blunting of the GIP response to glucose. Physiologic levels of serum insulin were attained. Therefore, the present study suggests the existence of negative feedback regulation of GIP release by endogenous insulin (pancreatico-GIP axis).