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Biomedical subjects

W G Pace

Publications and source records attributed to W G Pace.

At least 19 recordsLinked to original sources
PubMed1988

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.

Anastomosis, Surgical↗
PubMed1987

Initial clinical experience with a biofragmentable ring for sutureless bowel anastomosis.

Twenty-seven patients have had bowel anastomoses with a biofragmentable ring for sutureless bowel anastomosis. There were no complications associated with the anastomotic technique. One patient developed an ischemic stricture on the proximal side of the anastomosis due to compromised circulation. There was no leakage. Technical factors regarding the BAR anastomosis are described. A properly placed purse-string suture is of primary importance. Advantages appear to be a more rapid and easy anastomosis with better healing.

Aged↗
PubMed1986

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.

Animals↗
PubMed1985

A biofragmentable ring for sutureless bowel anastomosis. An experimental study.

A biofragmentable bowel anastomosis ring (BAR) for sutureless intestinal anastomosis is described with the laboratory results comparing the BAR to sutured and stapled anastomoses. There was equivalent healing with all three methods of anastomosis. However, "burst" pressure was highest at day zero and overall necrosis was least with the BAR. By virtue of these findings and being sutureless, it is hoped that the limits of safe bowel anastomosis can be extended.

Animals↗
PubMed1981

Pancreatic polypeptide in acute pancreatitis and small-bowel infarction in dogs.

Serum and urine concentrations of pancreatic polypeptide (PP) were measured during experimental acute hemorrhagic pancreatitis and small-bowel infarction in dogs. The mean serum PP concentration in animals with pancreatitis increased markedly after 1 hr and remained elevated, while the mean serum PP concentration in the animals with infarction showed a late trend to increase. The urine PP concentration in pancreatitis increased nonsignificantly, whereas, during bowel infarction, there was no increase. In the infarction group, PP clearance correlated with the serum PP concentration. During pancreatitis, PP was cleared independently of the serum PP concentration. The results suggest that during acute hemorrhagic pancreatitis there is an acute release of PP related to immediate cell injury in the pancreas. The high serum concentration of PP may lead to an override of the normal renal handling of PP. In small-bowel infarction there may be a delayed mode of PP release.

Acute Disease↗
PubMed1981

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.

Adult↗
PubMed1980

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.

Animals↗
PubMed1979

Alterations in gastrointestinal contents induced by elemental diets.

The effects of elemental diets on selected aspects of the rat colon were studied. Forty young male Sprague-Dawley rats were divided into 4 diet groups of 10 rats each: Purina Rat Chow (control); Flexical; Precision L-R; and Vivonex. All diets were fed ad lib to rats housed in pairs in wire-bottom cages. Two weeks after weight stabilization had been achieved all rats were killed and colon contents were collected for culture and short-chain fatty acid analysis on the Perkins-Elsoner 3920 gas chromatograph. Colon fecal butyric/acetic acid ratios of the rats in the 4 groups were: Rat Chow, 2.56; Flexical, 0.28; Precision L-R, 0.16; and Vivonex, 0.26. Bacterial cultures showed increased coliform and enterococcal species in the rats consuming elemental diets.

Acetates↗
PubMed1979

Gastric partitioning for morbid obesity.

The complication rate in jejunoileal bypass for morbid obesity is unacceptably high. Gastric bypass is technically difficult. In our series, 115 patients have undergone gastric partitioning for morbid obesity. The operation consists of stapling across the stomach below the gastroesophageal junction, leaving a gastric food reservoir of 50--60 cc. A 1 cm opening is left in the central portion of the staple line, allowing slow emptying into the distal stomach. The result is a reduced eating capacity and frequency which produce loss in weight. Three-quarters of the patients are women, and the age range is 17--62 years. Preoperative weights averaged 147 kg. Mean operative time was 48 minutes, and postoperative stay was 6.2 days. All patients were extensively evaluated preoperatively with upper GI series, cholecystogram, a number of blood chemistry tests, and endocrinologic and psychiatric consultations. All patients underwent a preoperative Minnesota Multiphasic Personality Inventory test. Cholecystectomy for cholelithiasis was performed on 18% of the patients at the time of operation. Of the seven patients operated on more than one year ago, five have lost an average of 31.6% of their preoperative weight. Of the 12 operated on less than one year but more than six months ago, eight have lost an average of 21% of their initial weight. The early failure rate of 33% has been reduced to 15% at present. One death occurred from pulmonary embolus 10 days following discharge, giving a mortality rate of .08%. The complication rate is 10%, comprising two pulmonary emboli, two psychoses, one wound dehiscence, one wound hernia, and ten wound infections, six of which were minor. There have been no complications of ulcer disease, reflux esophagitis, liver disease, renal disease, or metabolic disorders. Gastric partitioning is a safe, fast effective alternative for the surgical treatment of morbid obesity.

Adolescent↗
PubMed1978

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.

Animals↗
PubMed1978

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.

Adolescent↗
PubMed1978

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.

Animals↗
PubMed1977

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).

Acute Disease↗