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Biomedical subjects

I S Benjamin

Publications and source records attributed to I S Benjamin.

At least 127 records · Page 7Linked to original sources
PubMed1978

The early use of fine-needle percutaneous transhepatic cholangiography in an approach to the diagnosis of jaundice in a surgical unit.

Fine-needle percutaneous transhepatic cholangiography (PTC) was performed in a series of 46 patients with jaundice or suspected biliary tract disease. The ductal system was successfully outlined in each of 20 patients with dilated intrahepatic ducts and in 19 of 26 patients with intrahepatic ducts of normal calibre. There were two episodes of septicaemia after PTC, one of them fatal. Valuable accurate diagnostic information was obtained in all cases with biliary tract obstruction. A programmed approach to diagnosis of suspected obstructive jaundice is outlined. Fine-needle PTC is an acceptably safe procedure and need not be followed by immediate laparotomy.

Adult↗
PubMed1978

Parathyroid hormone and calcium homeostasis in acute pancreatitis.

Sequential daily measurements of plasma parathyroid hormone (PTH) have been performed in 89 patients with acute pancreatitis. A total of 439 PTH assays was obtained during 98 episodes of the disease. Three main patterns of PTH response were found. These responses were correlated with severity of disease graded by objective criteria and also to corrected serum calcium levels. The first type of PTH response was characterized by significantly elevated PTH levels soon after hospitalization with a subsequent decrease in levels to within the normal range by the third or fourth day of illness. This type of response was specifically associated with transient severe hypocalcaemia (corrected calcium less than 2.0 mmol/l). It was also associated with the most severe forms of disease and 6 of the 7 deaths. The second type of PTH response revealed initial PTH values in the upper level of the normal range (400--600 ng/l) while persistently low PTH levels were characteristic of the third type of response. Persistently low PTH levels were associated with normocalcaemia, and no patient in this group died. None of a group of 14 control patients exhibited the type 1 PTH response. An effective PTH response to an unidentified hypocalcaemic stimulus results in satisfactory calcium homeostasis in most patients with acute pancreatitis.

Acute Disease↗
PubMed1978

Changes in the nuclei of astrocytes following portacaval shunting and portacaval transposition in the rat.

Structural abnormalities are found in the astrocytes of the dentate nuclei of animals after portacaval shunting (PCS). These changes are also found in man in association with portal-systemic encephalopathy. To investigate the relationship between portal-systemic shunting and hepatocellular dysfunction in the pathogenesis of these changes, PCS and protacaval transposition (PCT) were performed in rats. PCT diverts portal blood into the systemic circulation, but retains normal total hepatic blood flow by perfusion with systemic venous blood. Liver function and mass are better preserved than after PCS. Abnormal glial cells were found in 4.03% of animals following sham operation, 13.45% following PCT, and 19.09% following PCS. Both experimental groups differed significantly from control animals, and the number of abnormal cells was significantly higher after PCS than after PCT. These findings are in keeping with the hypothesis that hepatocellular dysfunction plays an important role in addition to portal-systemic shunting in the aetiology of the structural changes in the brain associated with hepatic encephalopathy.

Animals↗
PubMed1977

Diagnosis and management of post-cholecystectomy symptoms: the place of endoscopy and retrograde choledochopancreatography.

Endoscopic retrograde choledochopancreatography (ERCP) was employed in 52 patients symptomatic after cholecystectomy in whom barium meal studies and intravenous cholangiography had failed to yield a diagnosis. Cannulation of the papilla of Vater was carried out in 50 of the patients in a mean time of 10 min. Diagnostic information demonstrating a pathological lesion or a normal biliary and pancreatic ductal system was obtained by means of endoscopy and ERCP in 48 cases. There were no serious complications. A pathological lesion was demonstrated in all but one of the patients presenting with jaundice, cholangitis or pancreatitis but the diagnostic yield was not as high in patients with vague upper abdominal symptoms. Endoscopy and ERCP are the investigative procedures of first choice in complex post-cholecystectomy cases in whom intravenous cholangiography fails, gives incomplete information or suggests normality in the face of continuing symptoms or clinical evidence of residual biliary disease.

Adult↗
PubMed1977

Portacaval transposition and subsequent partial hepatectomy in the rat: effects on liver atrophy, hypertrophy and regenerative hyperplasia.

Portacaval transposition diverts portal blood from the liver. It allows systemic venous blood to perfuse the portal bed. Body weight and liver weight have been followed before and after portacaval transposition and control procedures in rats, and the DNA activity ratio studied in the liver of rats after partial hepatectomy in protacavally transposed animals. The results suggest that the liver atrophy seen after portal diversion is a result of diversion of trophic substances in the portal blood rather than of a decrease in absolute liver flow. Recovery of liver weight after partial hepatectomy in portacavally transposed animals occurs within the same time as in control animals, and the time course and magnitude of regenerative hyperplasia, as assessed by liver DNA activity ratio, is unimpaired.

Animals↗
PubMed1976

The immune response in cirrhotic rats. The induction of tolerance to orally administered protein antigens.

Hepatic cirrhosis reduced the susceptibility of rats to the induction of tolerance by the oral administration of a protein antigen. Rats with portacaval shunt were rendered tolerant as readily as normal rats. The orally induced state of partial tolerance was shown to be dependent on thymus-dependent lymphocytes: B lymphocytes reacted normally to challenge when injected with T lymphocytes from normal rats. Several factors may contribute to the reduced responsiveness of the cirrhotic rats to the tolerance regime. First, the cirrhotic liver was shown to have a reduced capacity to separate immunogen from tolerogen. Second, because of the reduced phagocytic capacity of the liver, increased quantities of lipopolysaccharide, derived from intestinal microorganisms, enter the blood stream. These substances and products of hepatocyte necrosis have adjuvant activity and may therefore contribute to the changed state of responsiveness of rats with cirrhosis.

Administration, Oral↗
PubMed1976

The effects of portacaval shunting and portacaval transposition on serun IgG levels in the rat.

In rats subjected to end-to-side portacaval shunt and to portacaval transposition, serum IgG levels rose progressively by approximately 100% over a 5-week period. During the same period, sham-operated control animals showed only the increase expected with age. Rats with a portacaval shunt showed a greater fall in body weight and liver weight than did those with a portacaval transposition, and also showed a greater fall in levels of liver-synthesized proteins. Serum enzyme levels were markedly elevated during the first 48 hr after portacaval shunting, whereas after portacaval transposition the elevation was very small. Over the following 5 weeks enzyme elevation continued to be margiallly greater in the portacavallly shunted animals. Because IgG levels rose to a similar degree in both groups of animals, the prsent results support the hypothesis that hypergammaglobulinemia is due to the shunting of antigen-rich portal blood past the reticuloendothelial cells of the liver, and the hepatocellular damage does not play a major role in this process. The etiology of hypergammaglobulinemia in chronic liver disease in man may be similar.

Alanine Transaminase↗
PubMedDate not supplied

Portacaval transposition in the rat: definition of a valuable model for hepatic research.

Portacaval transposition (PCT) in rats results in a smaller loss of body mass and liver mass than end-to-side portacaval shunt (PCS). Detailed studies of liver function, mass and histology were not previously available and have been undertaken in two different strains of growing rat in order to define the value of this model. PCT rats gained weight normally, while only 50% of PCS rats regained their preoperative weight by the tenth week. Wet and dry weights of liver fell relative to control values after both operations, but the fall was significantly greater after PCS than after PCT: there were parallel changes in hepatocyte size. There was a marked rise in liver-associated enzymes in the first 2 days after PCS only, and minimal enzyme elevations persisted in this group. The extent of cellular damage seen histologically closely parallelled the rise in SGOT in individual rats. At 72 hr, PCS rats showed focal necrotic changes, and by 10 weeks there was marked fatty infiltration: PCT rats had normal histology or showed minimal changes. PCT therefore provides a model in which there is total portal diversion without the more severe effects of the conventional PCS on hepatic structure and function. This has particular value in studies of experimental hepatic encephalopathy, of hormonal and amino acid changes after portal diversion, and of factors initiating or controlling liver regeneration.

Alanine Transaminase↗
PubMedDate not supplied

Acalculous cholecystitis complicating hepatic intraarterial lipiodol: case report.

Hepatic intraarterial injection of Lipiodol has been used by various authors to enhance the diagnostic accuracy of computed tomography in hepatic tumors. The technique appears safe and seems free from serious complications when used judiciously. We report a case in which injection of hepatic intraarterial Lipiodol precipitated acalculous cholecystitis requiring urgent laparotomy.

Angiography↗
PubMedDate not supplied

Effect of perfusate albumin on organ viability and vascular responses in the in vitro dual-perfused rat liver.

Inclusion of albumin in the perfusate has been previously shown to be detrimental to liver function, but its effect on hepatic vascular reactivity remains unknown. The aim of this study was to determine the effects of albumin on hepatic arterial vascular reactivity and liver viability in the isolated dual-perfused rat liver. A total of 12 rat livers were perfused with Krebs-Bülbring buffer without (Group 1) and with (Group 2) addition of 1% bovine serum albumin (BSA) through the hepatic artery and portal vein for up to 5 h. Hepatic arterial responses to acetylcholine and sodium nitroprusside were studied at 30-min intervals. Liver viability was assessed by bile volume production, release of aspartate serine aminotransferase (AST) and lactic acid dehydrogenase (LDH), and histological examination. Hepatic arterial responses to acetylcholine were significantly attenuated in Group 2. No significant differences in sodium nitroprusside responses were noted. However, bile volume production in Group 2 was significantly decreased compared to Group 1. Effluent AST and LDH release increased significantly in Group 1 but not in Group 2. Histological results showed that sinusoidal endothelial cells and hepatocytes were well preserved without significant deterioration in either group, although there was a marked decrease in vasodilatation to acetylcholine in Group 2. This data suggested that the presence of albumin in the perfusate did not improve retention of smooth muscle reactivity and reduced endothelium-dependent vasodilatation and bile volume production during perfusion. However, improved liver parenchymal cell function was observed.

Acetylcholine↗
PubMedDate not supplied

A simple and accurate mathematical method for calculation of the EC50.

A simple, accurate, and speedy noncomputational technique for the calculation of the EC50 or any other concentration-related parameter of concentration-effect curves is presented. It avoids the necessity for graph construction or computational curve-fitting programs and allows accurate calculation of the EC50, where the value falls between two known concentrations The technique has been applied to a concentration-response curve constructed to hepatic arterial (HA) vasoconstrictor responses to HA injections of noradrenaline in an isolated dual-perfused rat liver preparation. EC50 values calculated by the new technique were compared to those calculated by conventional, established, noncomputational techniques. The new technique is faster, more accurate, and simpler to perform than other established noncomputational techniques used for the calculation of the EC50 and can be widely applied to many other pharmacological investigations.

Animals↗