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Biomedical subjects

W G Schenk

Publications and source records attributed to W G Schenk.

At least 37 records · Page 2Linked to original sources
PubMed1981

Effect of bile induced pancreatitis on tobramycin excretion in pancreatic fluid.

The objective of this study has been to lay the groundwork for a re-evaluation of the place of antibiotics in acute pancreatitis. This section has been devoted to determining if antibiotics excreted by the normal pancreas are excreted similarly in acute pancreatitis. Ten mongrel dogs were studied, each acting as its own control. Day 1: Operation--construction of pancreatic fistula. Day 2: Study of antibiotic excretion. Day 14: Operation--induction of acute focal pancreatitis. Day 15: Study of antibiotic excretion. Antibiotic concentrations in pancreatic fluid were studied by injecting tobramycin intravenously (5 mg/kg). Serum levels and excretion of the drug in the pancreatic secretion were then monitored over the next six hours. Results showed excretion of tobramycin reached bactericidal concentrations in pancreatic fluid from the normal and inflamed pancreas, with no significant differences (p = 0.2) between the excretion rates. The place of antibiotics in acute pancreatitis is discussed. Based on usual pathogens isolated in pancreatic abscesses, and their usual sensitivity patterns, tobramycin with Cephamandole are the antibiotics of choice in acute pancreatitis, and a clinical trial is indicated to evaluate their place in reducing complications and deaths in the disease.

Acute Disease↗
PubMed1980

Acute pancreatitis - ischaemia or hyperaemia?

There is no accepted specific treatment for acute pancreatitis in man in spite of extensive investigations. Evidence is presented based on histology, vascular and blood flow studies to support the hypothesis that acute pancreatitis is unlike most inflammatory conditions since a rapid and severe ischaemia develops in the pancreas. In dogs for example there is an instant and maintained reduction in pancreatic blood flow reducing by 72% at 3 hours. Various treatments have been advocated in acute pancreatitis. Based upon the effect of dextran 40 in improving pancreatic blood flow and percentage cardiac output, it would appear to be a treatment of choice in acute pancreatitis.

Acute Disease↗
PubMed1980

The effect of Trasylol and vasopressin on experimental pancreatitis.

A dog model was established to measure the hemodynamic changes occurring during experimental pancreatitis. The effect of treatment with Trasylol and vasopressin, beginning 60 minutes after induction of pancreatitis was assessed by their effect on the pancreatic hemodynamics. The pancreatic arterial blood flow fell by 72 per cent in the dogs with induced pancreatitis and treated only with saline solution. In contrast, the pancreatic blood flow fell by 58 per cent in the Trasylol group and 80 per cent in the vasopressin group. In addition, vasopressin had a detrimental effect on the cardiac output. Neither treatment altered the changes noted in the systemic blood pressure. Trasylol had a slight beneficial effect on experimental pancreatitis when assessed by its effect on the pancreatic hemodynamics. In contrast, vasopressin had a detrimental effect on the pancreatic hemodynamics.

Acute Disease↗
PubMed1979

Experimental acute pancreatitis: the changes in pancreatic oxygen consumption and the effect of Dextran 40.

A canine model was devised to measure the oxygen consumption of the pancreas in experimentally induced pancreatitis. Over the 120 minute investigation period the oxygen consumption fell by 63% in the presence of a diminishing pancreatic blood flow and constant arteriovenous percentage saturation across the pancreas. Dextran 40 has been previously shown to maintain the pancreatic circulation. Accordingly a second group of dogs was treated with Dextran 40 (1.5 ml/kg) 60 minutes after induction of the pancreatitis. This produced a significant increase in the pancreatic oxygen consumption and widening of the arteriovenous difference. Dextran 40 appears to reverse the hypoxia of the pancreas noted in acute experimental pancreatitis.

Acute Disease↗
PubMed1979

Hypercalciuresis in trauma patients on high-nitrogen enteral and parenteral diets.

Calcium balances in ten enterally or parenterally hyperalimented trauma victims were compared as protein intake was manipulated from 50.5 +/- 12.8 to 128.0 +/- 17.4 gm/day during an isocaloric metabolic balance study. Calciuresis increased as protein intake increased in all subjects, resulting in an average reduction in daily calcium balance of 195 +/- 65 mg/day (p less than 0.001). There was no difference in fecal calcium in the enterally fed subgroup. Total and "corrected" total serum calcium were lowered, and indirect evidence suggests that ionized calcium was lowered as well. The mechanism of the increase in urinary calcium is not fully elucidated, although it appears to be a direct effect on the kidney rather than an indirect influence of calcium homeostasis. It is suggested that a calorie/nitrogen ratio of about 360 be maintained in enteral and parenteral alimentation of trauma victims. Thus nitrogen balance can be maintained by the increased nonprotein calorie availability, and possible complications of increased calcium mobilization and excretion can be avoided.

Adolescent↗
PubMed1978

Hepatic blood flow measurement.

Although many experimental studies have been made to determine the total hepatic blood flow in steady circulatory states, very few have been done in unsteady states of either circulatory overload or underload. In this experiment, a comparison is made between total hepatic blood flow measured by the single injection of indocyanine green and the electromagnetic flow methods in the dog, in which circulatory overload was induced by dextran 40 infusion. While there was close correlation between the values obtained by the two methods in normal dogs, following dextran infusion the indirect indocyanine green method overestimated hepatic blood flow by 40% to 60%, using the electromagnetic method as a comparison standard. The reason for this discrepancy is not elucidated by these studies.

Animals↗
PubMed1978

Hepatic blood flow measurement III. Total hepatic blood flow measured by ICG clearance and electromagnetic flowmeters in a canine septic shock model.

The validity of the ICG clearance method for the measurement of THBF in abnormal circulatory states remains questionable. In this study THBF measured by this method is compared with the electromagnetic flow technique in a canine spetic model. Good correlation is demonstrated between the two in normal control animals. However, in the septic animals the ICG underestimated the electromagnetic flow result by 20%. This is true in both the high and the low cardiac output septic shock pictures that emerge. In the septic animals, the total hepatic blood flow as measured by the ICG was almost equal to the portal vein flow alone measured by the electromagnetic flowmeters suggesting that this was the quantity it was measuring in this abnormal state. Pathophysiologic mechanisms that may explain the discrepancy are given.

Animals↗
PubMed1978

Experimental pancreatitis: Effect of plasma and dextran on pancreatic blood flow.

In spite of extensive investigations, many aspects of the hemodynamic changes occurring in acute pancreatitis are understood poorly. A dog model was established in which continuous measurements of pancreatic arterial blood flow, cardiac output, and mean arterial blood pressure were made using electromagnetic flow probes and a pressure transducer, respectively. Pancreatitis was induced and the animals were monitored for 3 hours. In addition, control animals (group I) without pancreatitis also were done. All animals 50 ml of saline in the first hours. Three methods of therapy then were instituted in the dogs with pancreatitis and their effects were recorded. group I 6 dogs control animals no pancreatitis saline 50 ml/hr group II 10 dogs saline 50 ml/hr group III 6 dogs plasma 15 ml/kg over 45 min then saline 50 ml/hr group IV 10 dogs saline 50 ml and 1.5 ml/kg of dextran 40/hr These results confirm the observations made previously using a transillumination technique--that the pancreatic circulation rapidly reduces in acute pancreatitis. Administration of plasma produced a significant (P less than 0.05) but transient increase in the cardiac output and pancreatic blood flow; however, the blood pressure remained low. Dextran 40 minimally increased cardiac output, but it significantly improved the blood pressure and maintained the pancreatic blood flow. Low-dose, low-molecular weight dextran 40 appears to help to maintain pancreatic blood flow in acute pancreatitis. The possible mechanisms concerning the made of action of dextran 40 will be discussed.

Animals↗
PubMed1977

Hepatic blood flow measurement. A comparison of the indocyanine green and electromagnetic techniques normal and abnormal flow states in the dog.

Very few studies have compared the total hepatic blood flow using the Indocyanine green (ICG) method with the instantaneous electromagnetic flow method under unsteady circulatory conditions. In this study, a hypotensive circulatory state was produced by rapid hemorrhage in 14 dogs. Total hepatic blood flow was measured using the ICG single injection method, comparing it with the electromagnetic flow method. After confirming the validity of the ICG single injection method in measuring total hepatic blood flow in the steady state, the experiment was then carried out using 23 normal healthy dogs. The close correlation between the ICG clearance technique and the electromagnetic values under normal steady state was confirmed. However, after hemorrhage the indirect ICG method estimated only 71% of the simultaneous electromagnetic flow value. It is reasonable to assume that while the electromagnetic method continues to measure the actual total hepatic blood flow in both the steady and unsteady states, the ICG clearance method measures only the functional hepatic blood flow which is reduced due to shunting or impaired hepatocellular function in the unsteady and hypotensive circulatory state.

Animals↗
PubMed1977

Hypertension of aortic coarctation: the role of renal and other factors.

In order to establish the relationship between the renal and other factors associated with the hypertension of coarctation of the aorta, aortic strictures were created in two groups of adult dogs (Groups A and B). Group B in addition had transference of total renal blood flow proximal to the stricture to eliminate the renal aspects of the hypertension. Carotid and femoral artery pressures were measured at monthly intervals for 24 weeks. Group A developed progressive generalised hypertension while Group B only developed hypertension proximal to the coarctation. The dominant role of a renal factor producing a generalised vascular response is confirmed, the localised proximal hypertension in Group B reflecting the mechanical obstruction imposed by the aortic stricture. There is no evidence to suggest that other organs distal to the coarctation are implicated in the development of arterial hypertension.

Animals↗
PubMed1977

Recent advances in the management of trauma.

Delivery of the most up-to-date trauma care requires a well-trained team of four physicians and four nurses to carry out the initial management of a single major injury patient (Border et al, 1975). Ventilatory insufficiency, circulatory insufficiency, and wounds must all be treated promptly and simultaneously.

Cardiovascular Diseases↗
PubMed1976

Improvement in blood flow through a critical arterial stenosis by defibrination with ancrod.

Using electromagnetic flow probes, cardiac output and hind limb blood flow were measured in dogs in which one hind limb had been rendered ischemic. Four dogs served as controls; seven were defibrinated by intravenous infusion of ancrod, 1 unit/kg, over a 30-minute period. In both groups, hematocrit readings remained constant, but cardiac output fell (this was attributed to barbiturate anesthesia), as did flow in the normal hind limb. In the controls after three hours, flow in the ischemic hind limb had decreased by 34%, but in the treated animals it had increased by 20%. The difference was statistically significant (P less than .001). The selective increase in blood flow in the ischemic limb may be explained by the greater reduction in blood viscosity at low shear rates achieved by defibrination.

Ancrod↗