Biomedical subjects
Publications and source records attributed to J Bosch.
An ELISA was developed for the detection of antibodies to the exotoxin of Corynebacterium pseudotuberculosis. Experience with the test for control of caseous lymphadenitis in goats in the province of Gelderland is discussed.
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The efficacy and complications of esophageal tamponade as the first procedure in the routine management of acute variceal hemorrhage were evaluated in 151 consecutive bleeding episodes treated at a specialized unit. The Sengstaken-Blakemore tube was employed in the 118 cases in which emergency endoscopy demonstrated bleeding esophageal varices, and the Linton-Nachlas balloon in the 33 cases with bleeding from gastric varices. Hemostasis lasting at least 24 hr was obtained in 91.5% of cases treated with the Sengstaken-Blakemore balloon and in 88% of those treated with the Linton-Nachlas balloon. Permanent hemostasis was obtained in 47.7% of all cases. The only severe complication noted in these 151 episodes of bleeding treated by tamponade was pulmonary aspiration, which was detected in 10% of cases. This complication was related to the presence and degree of encephalopathy (P less than 0.001) and was prevented by orotracheal intubation prior to tamponade. These results indicate that balloon tamponade continues to be a reliable and valuable method to arrest bleeding from esophagogastric varices.
Hepatic plasma flow was assessed with sorbitol (hepatic extraction = 0.96) at steady state. After infusion of 50 mg/min for 3 h, total and renal sorbitol clearances were calculated, and the extrarenal clearance was obtained by taking the difference between the two. In normal volunteers, the mean (+/- SD) extrarenal sorbitol clearance was 10.6 +/- 2.1 ml/min.kg. In patients with various liver diseases, it was correlated more closely to the fractional clearance of indocyanine green (r = 0.83, n = 57) than the galactose elimination capacity (r = 0.66, n = 55). Hepatic vein catheterization showed that the hepatic extraction of sorbitol was always much higher than the extraction of indocyanine green; there was no evidence for extrahepatic, extrarenal sorbitol elimination. On the basis of these findings, sorbitol is kinetically superior to indocyanine green and, although the noninvasively determined extrarenal sorbitol clearance at steady state may not be equal to total hepatic plasma flow, it may at least be regarded as a measure of parenchymal liver plasma flow.
Propranolol, a non-selective beta-blocker, is known to decrease glucagon release in normal subjects. The present study was aimed at investigating the effects of propranolol on the hyperglucagonism commonly observed in patients with cirrhosis. Eight cirrhotic patients and 6 matched healthy controls were studied. The plasma concentrations of glucagon, insulin, c-peptide and glucose were measured in basal conditions and after stimulating glucagon secretion by an i.v. infusion of arginine (0.4 g/kg/30 min). The study was repeated 24 h later after inducing beta-blockade by the i.v. infusion of propranolol (10 mg). In baseline conditions, patients with cirrhosis, despite normal levels of insulin and glucose, had a marked hyperglucagonism (654 +/- 303 pg/ml vs. 269 +/- 90 in controls, P less than 0.01). Prior to propranolol, arginine infusion caused greater glucagon release in cirrhotics (71 +/- 31 ng.h.ml-1) than in controls (33 +/- 17 ng.h.ml-1, P less than 0.02), but despite a similar insulin secretion (assessed from c-peptide), blood glucose did not increase. After propranolol, glucagon secretion decreased as expected in controls (29 +/- 12 ng.h.ml-1, P less than 0.05) but experienced a paradoxical increase in cirrhotics (113 +/- 64 ng.h.ml-1, P less than 0.05). Again, despite the marked increase in glucagon release, there was no increase in glucose production, providing further evidence of the glucagon resistance that accompanies hyperglucagonism in cirrhosis. Our results suggest that hyperglucagonism with glucagon resistance might be the initial disturbance in carbohydrate metabolism in patients with cirrhosis. Contrary to what could be expected, propranolol does not correct but further accentuates this disturbance.
The effects of somatostatin infusion on splanchnic and systemic hemodynamics and plasma glucagon levels were investigated in rats with portal hypertension. Forty-four male Sprague-Dawley rats were studied. Portal hypertension was induced in 26 rats by partial portal vein ligation (PVL). These rats were divided in two experimental groups to receive blindly 1) somatostatin (PVL-SMT, n = 13) at a dose of 25 micrograms/kg body wt during 30 min preceded by a bolus injection of 15 micrograms/kg body wt or 2) placebo (saline) (PVL-P, n = 13) infused at the same rate as in the previous group. The remaining 18 rats were used as normal controls and received somatostatin (n = 9) or saline infusion (n = 9). Regional blood flows and cardiac output were measured using radioactive microspheres. Arterial and portal pressures were also measured. In portal hypertensive rats somatostatin infusion produced significant reductions in the increased portal venous inflow, reductions in portal pressure, and significantly increased portal venous resistance. Reduction of portal venous inflow was due to splanchnic vasoconstriction, evidenced by increased splanchnic arteriolar resistance. No significant differences were observed in systemic hemodynamic parameters between PVL-SMT and PVL-P rats. Plasma glucagon levels were significantly reduced by somatostatin to levels similar to those observed in sham-operated rats. In sham-operated rats, somatostatin also caused significant reduction in portal venous inflow and plasma glucagon concentration, although these changes were of lesser magnitude than in portal hypertensive rats.(ABSTRACT TRUNCATED AT 250 WORDS)
The measurement of recirculation during two-needle hemodialysis has been shown to provide valuable information concerning distal hemoaccess stenosis and the loss of effective dialysis. Reference sources have suggested that levels of recirculation above 20% call for further investigation. We proposed a technique for routine recirculation measurement and studied 20 stable hemodialysis patients using this method. We found that all patients had recirculations of less than 10%. We also studied 2 patients with angiographically proven stenosis and found 1 patient with a recirculation of less than 20%. Routine recirculation testing provides valuable information about hemoaccess integrity and using our techniques, recirculation greater than 10% is an indication for further study.
Portal hypertension is a common complication of chronic liver disease. Conventional therapy consists of surgery and palliative measures for the hemodynamic problem. It has been recently reported that somatostatin may reduce portal pressure without altering the systemic circulation and so reducing hepatic blood flow. This peptide also causes a significant fall in azygos circulation in patients with esophageal varices. The mechanism of this effect is unclear although suppression of intestinal vasodilating hormones and of glucagon have been claimed to play a role. Comparative clinical studies have shown somatostatin to be superior to the standard vasopressin treatment. Recent findings suggest that the efficacy of somatostatin can be increased by administering this peptide in repeated intravenous bolus injections. New derivatives, specially long-acting peptides, may eventually prove beneficial in the chronic treatment of this complication.
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In the past recent years there have been several major innovations in the diagnosis and evaluation of portal hypertension. These include the application of new endoscopic, ultrasonographic and haemodynamic techniques that allow a better evaluation of the portal hypertensive patient, specially when prophylactic medical therapy is considered. Ultrasonography is very useful to assess the patency of the portal vein. The association of a pulsed Doppler flowmeter increases its accuracy and allows the non-invasive estimation of the direction and magnitude of portal blood flow. Endoscopic measurements of variceal pressure may help to understand the mechanism of variceal bleeding, and perhaps might permit to assess the risk of haemorrhage in the individual patient. In addition to the measurement of portal pressure, measurement of blood flow through the azygos vein has been the major innovation in the haemodynamic evaluation of portal hypertension. Azygos blood flow represents an index of blood flow through gastroesophageal collaterals and varices draining in the azygos vein. This technique has been very useful in the development of new forms of pharmacological therapy for portal hypertension.
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To characterize bleeding from gastric red spots in patients with cirrhosis, three groups of patients were studied: (a) 11 cirrhotic patients bleeding from gastric red spots, (b) 18 nonbleeding cirrhotic patients without gastric red spots, and (c) 13 noncirrhotic patients with endoscopic normal mucosa (controls). Histologic examination of antral biopsy specimens revealed a diffuse capillary ectasia without inflammation in 8 of the 11 cirrhotic patients with gastric lesions. Morphometric analysis disclosed a significantly greater mean mucosal capillary cross-sectional area in cirrhotic patients with gastric lesions (mean +/- SE, 1371 +/- 320 microns2) than in those without gastric lesions (541 +/- 61 microns2) (p less than 0.005) or controls (353 +/- 20 microns2) (p less than 0.001). Hypergastrinemia was detected in 8 of the 11 cirrhotic patients with lesions, in 2 of the 18 cirrhotic patients without gastric lesions, and in none of the controls (p less than 0.001). Gastrin serum levels correlated significantly (r = 0.80) with mean mucosal capillary cross-sectional area in patients with cirrhosis. Pepsinogen I serum levels below 20 ng/ml were observed in 7 of the 11 cirrhotic patients with lesions, in 1 of the 18 cirrhotic patients without lesions, and in none of the controls. These data indicate that bleeding from gastric red spots in patients with cirrhosis is a distinct entity characterized by vascular ectasia of the gastric mucosa. This condition seems to be associated with hypergastrinemia and low serum levels of pepsinogen I.
The effects of beta-blockade with propranolol and of alpha-adrenergic stimulation with methoxamine, a powerful alpha-agonist, on azygos blood flow and on systemic and hepatic haemodynamics were investigated in 26 cirrhotic patients with portal hypertension. Beta-adrenergic blockade with propranolol (n = 12), evidenced by a significant reduction of heart rate (-17 +/- 1%, P less than 0.001) and cardiac index (-17 +/- 2%, P less than 0.001), caused a mild but significant decrease of hepatic venous pressure gradient (-10 +/- 2%, P less than 0.05) and a marked fall of azygos venous blood flow (-31 +/- 5%, P less than 0.05). Alpha-adrenergic stimulation with methoxamine (n = 14), manifested by a significant increase of mean arterial pressure (19 +/- 2%, P less than 0.001), mimicked the effects of propranolol on hepatic venous pressure gradient (-10 +/- 4%, P less than 0.05) and cardiac index (-11 +/- 2%, P less than 0.001). However, azygos blood flow was not significantly reduced by methoxamine (0.7 +/- 0.1 vs 0.6 +/- 0.1 l/min). On the contrary, hepatic blood flow was significantly reduced by methoxamine (-19 +/- 4%, P less than 0.01) but not by propranolol (-7 +/- 7%, ns). Similarly, in 8 patients who received methoxamine after being beta-blocked by propranolol, azygos blood flow, that was markedly reduced by beta-blockade, did not experience a further reduction but increased slightly by alpha-adrenergic stimulation, while hepatic blood flow, that was not reduced by propranolol, decreased significantly during the subsequent methoxamine infusion.(ABSTRACT TRUNCATED AT 250 WORDS)
The prevalence and type of portal hypertension (PH) in primary biliary cirrhosis (PBC) and their relationship with liver lesions have been investigated in 32 patients with the disease. Portal hypertension was considered when oesophageal or gastric varices were observed by endoscopy and/or when hepatic venous pressure gradient measured by hepatic vein catheterization was greater than 6 mmHg. Within 3 days of endoscopy, a liver biopsy was performed for histological staging and semiquantitative grading (0 to 3+) of portal and sinusoidal fibrosis, portal inflammation, piecemeal necrosis, lobular necrosis, cholestasis, as well as the presence of granulomas and Mallory's hyaline. Twenty patients (62.5%) had portal hypertension, five of them showing presinusoidal PH (15.5%) and the remaining 15 (47%) with sinusoidal component. The four patients in stage IV had sinusoidal PH and the only patient in stage I had no PH. The prevalence of portal hypertension was similar in patients in stage II (57%) and stage III (55%), but presinusoidal PH was only observed in patients in stage II. Patients with PH showed significantly higher portal inflammation and piecemeal necrosis than patients without PH. By contrast, there were no differences in portal and sinusoidal fibrosis, nor in the other histologic features. These results indicate that portal hypertension is common in PBC and it may be present in the early stages of the disease. The fact that presinusoidal PH was only observed in patients in stage II suggests that portal hypertension is initially of presinusoidal type, and then as the disease progresses is joined by a sinusoidal component.
We describe the clinical presentation and pathological features of an infantile fibrosarcoma of the femur that occurred in a 3 1/2-month-old male infant. The tumor grew rapidly, reaching large size within a few months, finally requiring amputation. The tumor was poorly circumscribed, infiltrating the adjacent soft tissue extensively. Microscopically, it was a highly cellular tumor composed of immature-appearing spindle-shaped cells. Ultrastructural study revealed mesenchymal cells with fibroblastic and histiocytic differentiation.
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