Biomedical subjects

T A Stein

Publications and source records attributed to T A Stein.

At least 37 records · Page 2Linked to original sources

PubMed1989

Safety of endoscopy in the immediate postoperative period following gastric anastomosis.

The safety of gastrointestinal endoscopy in the immediate postoperative period following partial gastrectomy was assessed in ten dogs. Endoscopy was performed preoperatively and at 1, 2, 3, and 7 days postoperatively. The mean pressures required to perform an adequate endoscopy varied from 17 to 20 mm Hg. Following partial gastrectomy, the abdominal wall was closed with a zipper to facilitate inspection of the gastric anastomosis. No leakage of air or intra-abdominal abscesses were seen following endoscopy. The results of this study suggest that endoscopy can be safely performed in the immediate postgastrectomy period.

Animals↗

PubMed1989

Role of reactive oxygen metabolites in early cardiopulmonary changes of acute hemorrhagic pancreatitis.

The role of reactive oxygen metabolites in extrapancreatic organ dysfunction associated with acute hemorrhagic pancreatitis was studied in dogs. Experimental pancreatitis was induced by the intraductal infusion of activated trypsin and taurocholate. Cardiac output, pulmonary and systemic blood pressure, pulmonary wedge pressure, central venous pressure, heart rate, blood gases and serum amylase were measured. Cardiac index, pulmonary and systemic vascular resistance, and the right and left stroke work were calculated. Systemic arterial and venous blood pressure and cardiac index gradually declined over 6 hr, while pulmonary mean blood pressure and pulmonary vascular resistance increased. Pretreatment of pancreatitis with catalase and superoxide dismutase prevented the rise in mean pulmonary blood pressure, moderated the rise in pulmonary vascular resistance, and decreased the rate and extent of the fall in cardiac index. These data suggest that reactive oxygen metabolites may play some role in the extraabdominal organ manifestations of acute pancreatitis.

Acute Disease↗

PubMed1989

Diagnostic value of liver function tests in bile duct obstruction.

Serological tests may be of value in differentiating acute and chronic bile duct obstruction because the rate of alteration of hepatic cellular integrity and function will affect the rate of cellular product release. In a canine model the common bile duct was obstructed either suddenly (N = 7) or gradually (N = 5). A control group (N = 5) had the common bile duct dissected free from the surrounding tissues. Blood was taken before and 1, 2, 4, 7, 11, 14, 17, 21, and 28 days after initiating obstruction. Serum alkaline phosphatase, bilirubin, aspartate aminotransferase, alanine aminotransferase, ornithine carbamyl transferase, and gamma-glutamyl transferase levels were significantly greater with sudden compared to gradual occlusion, and the values were larger than those in the control. The range of values of alkaline phosphatase, bilirubin, and aspartate aminotransferase did not overlap in the acute and chronic groups at specific times. Serum albumin and total protein were normal in all groups. The magnitude of alkaline phosphatase, aspartate aminotransferase, and bilirubin elevation may help in the differentiation of acute and chronic biliary obstruction.

Alanine Transaminase↗

PubMed1989

Biliary and pancreatic excretion of cefamandole.

After intravenous infusion of secretin and cholecystokinin in six dogs, cefamandole (50 mg/kg of body weight) was given intravenously for 10 min. Samples of serum, bile, pancreatic juice, liver, pancreas, fat, and muscle were collected over a 2-h period. Cefamandole levels were measured by a microbiological assay. The highest levels were as follows: serum, 160 micrograms/ml; bile, 3,071 micrograms/ml; pancreatic juice, 7 micrograms/ml; liver, 101 micrograms/g; pancreas, 44 micrograms/g; muscle, 20 micrograms/g; and fat, 14 micrograms/g. Levels in pancreatic juice were extremely low compared with levels in pancreatic tissue, suggesting the existence of a barrier to excretion at the ductal membrane.

Animals↗

PubMed1989

A modified retention suture technique with external and internal "booties" to close difficult abdominal wounds.

In a patient with acute hemorrhagic pancreatitis complicated by pancreatic abscess, closure of the abdominal wall 7 days following marsupialization was difficult owing to the marked distension and edema of the bowel wall, especially the transverse colon. A simple technique using retention sutures with internal and external rubber "booties" above and below the fascia was used to prevent injury to the edematous bowel. The rubber catheters, or "booties," were removed at the bedside, thus making it a simple procedure in a difficult situation.

Abdominal Muscles↗

PubMed1989

Urinary L-valyl proline in patients with aortic aneurysms.

Recent evidence indicates that metabolism of elastin may be altered in patients with different types of infrarenal aortic disease and that the phenotypic expression of aortic disease may be dependent on the balance between aortic elastase and antiprotease activity. The dipeptide L-valyl proline (LVP) is a specific amino acid sequence for elastin and can be quantitated by high performance liquid chromatography analysis of the urine. This study was done to determine if alterations in systemic elastin metabolism could be detected in patients with different types of infrarenal aortic disease by quantitating urinary LVP. Patients were divided into one of five groups and had urine analyzed for LVP. These are control, no known aortic disease (n = 12); occlusive aortic disease (n = 10); elective abdominal aortic aneurysms (AAA) (n = 26); ruptured AAA (n = 5), and multiple aneurysms (n = 4). Urine values were correlated with aortic elastase and aortic antiprotease activity. Urinary LVP was significantly higher in patients with multiple aneurysms (1,209 micrograms per milliliter of urine) as compared with all of the other groups. Patients with elective AAA had significantly higher urinary LVP (40.5 micrograms per milliliter of urine) than patients with occlusive disease (9.1 micrograms per milliliter of urine) and those in the control group (4.2 micrograms per milliliter of urine). Patients with ruptured AAA did not have significantly elevated urinary LVP compared with other groups (18.6 micrograms per milliliter of urine). Urinary LVP increased significantly as aortic elastase and aortic elastase and antiprotease activity increased. These data suggest that elastin metabolism, as reflected by urinary LVP, is altered in patients with aortic aneurysmal disease and provide further evidence to support the concept that systemic elastin metabolism is altered in patients with different types of infrarenal aortic pathologic findings.

Aorta, Abdominal↗

PubMed1988

Starvation and mucosal prostaglandin-E2 in gastric stress ulceration.

To determine whether starvation increases the susceptibility of the gastric mucosa to stress ulceration and whether this effect is linked to a change in the mucosal level of prostaglandin-E2 (PGE2), 100 Holtzman rats were divided into five groups and deprived of food for 0, 12, 24, 48 and 72 h. Then, ten animals within each group were stressed by cold restraint. At the end of the stress period, all these animals as well as their unstressed counterparts were killed, the number of gastric ulcers were counted, and mucosal levels of PGE2 were assayed. Fasting alone caused no ulcerations but a decrease in mucosal PGE2 during the initial 24 h (p less than .05). However, there was a subsequent increase in mucosal PGE2, possibly related to the release of free fatty acids during starvation. Starvation and stress caused a marked and consistent reduction of the mucosal PGE2 and an increase in the number of mucosal ulcerations directly related to the duration of starvation (p less than .05).

Animals↗

PubMed1988

Glucose and alanine absorption following massive small bowel resection.

A 90% small bowel resection in 8 dogs resulted in a significant decrease (p less than 0.05) in D-xylose and D-glucose absorption during the early postoperative period. The absorptive capacity of the residual gut with regard to L-alanine, however, remained unchanged. Anemia and hypoalbuminemia also occurred in time, suggesting a malabsorptive state. Control studies were performed in 8 dogs with small bowel transections. The results suggest that a high protein diet might be of benefit during the early postoperative period after massive small bowel resection.

Absorption↗

PubMed1987

High-performance liquid-chromatographic assay for prostaglandins with the use of p-(9-anthroyloxy)phenacyl bromide.

Gastric mucosa of rats and swine was incubated in buffer for 1 min to produce prostaglandins (PGs). After extraction and derivatization with p-(9-anthroyloxy)phenacyl bromide, the prostaglandin esters were determined by high-performance liquid chromatography. A 20-microliter sample was injected into a microparticulate silica gel column with a mobile phase of dichloromethane-acetonitrile-methanol (90:9:1). At a flow-rate of 1.5 ml/min the retention times of the prostaglandin esters were 7.14 min (internal standard), 7.90 min (PGF2), 10.05 min (thromboxane2), 12.26 min (6 alpha-keto-PGF1 alpha) and 13.98 min (PGF2 alpha). In spite of high sensitivity (0.1 ng per sample) for PGE2 and PGF2 alpha, only PGE2 synthesis was observed.

6-Ketoprostaglandin F1 alpha↗

PubMed1987

Picogram measurement of prostaglandin E2 synthesis by gastric mucosa by high-performance liquid chromatography.

Prostaglandin biosynthesis by gastric mucosa was determined by a 1-min incubation, solvent extraction, and reaction with panacyl bromide. The prostaglandin ester was measured by normal-phase high-performance liquid chromatography. The prostaglandin E2 levels of normal gastric mucosa of rats and swine were 90.6 +/- 31.0 and 79.8 +/- 39.8 pg/min/mg tissue, respectively. This method was sensitive to 40 pg and specific for prostaglandin E2.

Animals↗

PubMed1987

Arachidonic acid protection of rat mucosa against stress ulceration.

To evaluate the effect of arachidonic acid (AA), a prostaglandin precursor, on the mucosal level of PGE2 and its possible protective role against stress ulcerations, 40 Holtzman rats were divided into four groups: Group I intragastrically receiving 1 ml of normal saline (NS); Group II, NS pretreatment followed by stress; Group III, intragastric AA pretreatment without stress; and Group IV, intragastric AA followed by stress. AA was administered as a 120 mM solution in a nonionic detergent, adjusted to a pH of 8.0. Stress was provided by the cold-restraint method. After sacrifice, the number of gastric mucosal ulcerations were counted. Specimens of nonulcerated mucosa were assayed for PGE2 by derivatization with panacyl bromide and by using high-performance liquid chromatography. The animals in Groups I, III, and IV developed no gastric ulcerations and their mucosal prostaglandin E2 remained at a normal level, while those in Group II had a significant reduction of mucosal PGE2 (P less than 0.05) and a significantly increased number of gastric ulcerations (P less than 0.002). These data indicate that stress-induced mucosal ulcerations are associated with significant decreases in the gastric mucosal levels of PGE2. Intragastric administration of arachidonic acid prevents the formation of stress mucosal ulcerations and maintains a normal level of mucosal PGE2.

Animals↗

PubMed1987

Comparison of intraoperative ultrasonography and cholangiography in detection of small common bile duct stones.

High-resolution intraoperative ultrasonography was compared with conventional radiographic imaging in the detection of small common bile duct (CBD) stones (less than 5 mm in diameter). Sixteen mongrel dogs had laparotomy and ligation of distal CBD; 1 week to 10 days later, 0-3 gallstones of varying sizes (2-5 mm) were introduced into the dilated CBD (6-16 mm). High-resolution intraoperative ultrasonography of the CBD and a conventional intraoperative cholangiogram were performed to detect the presence and number of stones. The results of these two tests were evaluated independently by two ultrasonographers and two surgeons. There were 21 true-positive and five false-negative readings by sonogram compared with 17 and 9, respectively, by cholangiogram. Sensitivity of the sonogram was 81% and 65.4% by cholangiogram. Score of accuracy was 1.06 and 1.62 by cholangiogram and 0.81 and 0.87 by ultrasound (p less than 0.05). Intraoperative ultrasonography was found to be more sensitive in detecting small CBD stones when compared with intraoperative cholangiogram.

Animals↗

PubMed1986

Blood-pancreatic juice barrier to antibiotic excretion.

Antibiotics were given intravenously to dogs with chronic pancreatic fistulas, and serum and pancreatic juice levels were measured. Despite adequate serum values, gentamicin, tetracycline, clindamycin, and moxalactam did not appear in the pancreatic juice, which suggested a barrier to their excretion. In contrast, chloramphenicol reached a peak concentration in the pancreatic juice that amounted to 36 percent of the peak serum value. In the pancreatic juice, ampicillin, cefoxitin, and cefamandole reached only 5 percent of the peak serum values but were still within the therapeutic range. We have concluded that there is a blood-pancreatic juice barrier to some antibiotics, which leads to selective excretion.

Ampicillin↗

PubMed1986

The effect of verapamil on pancreatic exocrine secretion.

This study set out to examine the effects of a Ca++ channel blocker, verapamil, on pancreatic exocrine secretion because of the known relationship between amylase secretion and intracellular Ca++. Pancreatic secretion was stimulated in dogs by infusing secretin and cholecystokinin. Verapamil was found to inhibit the secretion of amylase but to have no effect on lipase, trypsin, or total protein. There was no effect on the secretion of water and bicarbonate. To determine the possible physiologic significance of these findings, the pancreas was stimulated by a meat meal, and verapamil was found to inhibit amylase secretion again and in addition to inhibit the secretion of water and bicarbonate. The results suggest that verapamil has an inhibitory effect on amylase secretion by blocking the influx of Ca++ into the acinar cell and has an indirect effect leading to inhibition of water and bicarbonate secretion from the duct cells.

Amylases↗

PubMed1985

Changes in bile salt composition after cholecystectomy and ileal resection.

The effect of ileal resection and cholecystectomy on bile salt metabolism was studied in female prairie dogs 4 weeks after either a sham laparotomy, cholecystectomy, ileal resection, or cholecystectomy and ileal resection. Bile was collected from a common bile duct cannula at hourly intervals for 12 hours. Pool sizes and synthetic rates of primary and secondary bile salts were determined from washout curves. Cholate, chenodeoxycholate, deoxycholate, and lithocholate levels were determined by gas chromatography from pooled collections of bile. After cholecystectomy and ileal resection, the pool sizes of primary and secondary bile salts were significantly reduced to amounts that were much less than the pool sizes after either procedure alone. Primary bile salt synthesis was significantly increased after combined cholecystectomy and ileal resection, to the same degree as cholecystectomy alone. After the combined procedures, there was a decrease in the proportion of cholate in hepatic bile associated with an increase in chenodeoxycholate, deoxycholate, and lithocholate levels. The data suggest that after the loss of both ileum and gallbladder the bile salt pool sizes are drastically reduced, the synthesis of primary bile salts is increased, and the proportion of secondary bile salts is increased. Cholecystectomy should be avoided, if possible, in patients with ileal resection in order to conserve the bile salt pool and prevent severe fat malabsorption.

Animals↗

PubMed1985

Nutritional effects of postgastrectomy reconstructions.

To compare the nutritional effects of two modes of reconstruction after total gastrectomy, a Hunt-Lawrence pouch was constructed in five mongrel dogs, whereas five other dogs had a simple Roux-Y esophagojejunostomy performed. Total body weight, daily food intake, serum albumin values, and intestinal absorption of carbohydrates, fats, and amino acids were evaluated in both groups over a period of 3 months. All values decreased postoperatively when compared with the preoperative values; however, there was no significant difference between the two groups. This study suggests that there is no nutritional benefit from a Hunt-Lawrence pouch over a simple Roux-Y esophagojejunostomy after total gastrectomy.

Animals↗

PubMed1985

Hepatic fat accumulation during liver regeneration.

Fat accumulates in the regenerating liver after partial hepatectomy. The role of intracellular acyltransferases in the synthesis of triglycerides was studied in the liver. Two-thirds hepatectomy was performed in 14 rats. An additional 14 rats had laparotomy only (sham group). Animals were sacrificed at 18 or 24 hr after operation. After 18 hr, microsomal sn-glycerol 3-phosphate acyltransferase specific activity was increased from 708 to 956 pmole of glycerol 3-phosphate incorporated X min-1 X mg-1 protein and the triglyceride content was increased from 2.2 to 12.6 mg/g liver. At 24 hr the microsomal enzyme activity was again increased from 742 to 1203 pmole of glycerol 3-phosphate incorporated X min-1 X mg-1 protein and the triglyceride content rose from 1.9 to 13.9 mg/g liver. A correlation existed between the microsomal enzyme activity and the triglyceride level (r = 0.608, P less than 0.05). The mitochondrial enzyme activity was not increased. At 24 hr peroxisomal dihydroxyacetone acyltransferase activity was elevated from 375 to 523 pmole of dihydroxyacetone phosphate incorporated X min-1 X mg-1 protein but showed no correlation with the triglyceride content; the microsomal activity of the enzyme was not increased. Cytoplasmic NAD+-dependent alpha-glycerol 3-phosphate dehydrogenase decreased by 24 and 32% at 18 and 24 hr. These data indicate that the microsomal sn-glycerol 3-phosphate acyltransferase activity has a major role in promoting triglyceride synthesis during liver regeneration.

Acyltransferases↗

PubMed1985

Effect of steroids on the cardiac output and renal changes of bacteremia.

The effects of methyl prednisolone pretreatment in dogs prior to a bacterial infusion were measured in relation to cardiac output, blood pressure, intrarenal blood flow, and glomerular filtration rate. In dogs not pretreated with steroid, cardiac output fell 61.1 per cent 30 min postbacterial infusion and remained depressed for the balance of the experiment. Pretreated animals showed a similar 61 per cent depression in cardiac output immediately following bacterial infusion, but then experienced recovery of cardiac output and blood pressure to levels not significantly different from controls at the conclusion of the experiment. Changes in outer cortical bloodflow and glomerular filtration rate were not affected by steroid pretreatment. Based on the above data, the author concludes that the salutary effect of steroid pretreatment on cardiovascular dynamics occurs independently of changes in renal function.

Animals↗