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Biomedical subjects

M Miyachi

Publications and source records attributed to M Miyachi.

At least 37 records · Page 2Linked to original sources

In vitro and in vivo expression of inducible nitric oxide synthase during experimental endotoxemia: involvement of other cytokines.

In this study, we investigated the expression of genes for inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-alpha), interleukin 1 beta (IL-1 beta), interleukin 6 (IL-6) of Kupffer cells in the presence of lipopolysaccharide (LPS), and the tissue expression of iNOS in a rat liver after LPS injection at various time intervals. The effects of L-NG-nitroarginine-methyl-esther HCI (L-NAME), a NO inhibitor, also were examined. The mRNA transcripts of TNF-alpha, IL-1 beta, and IL-6 were rapidly detected no more than at 1 h after LPS stimulation, whereas the iNOS transcript was detectable from 3 h after LPS stimulation and maximally increased at 12 h. This fact suggested that these early induced cytokines were related to expression of iNOS. Using an anti-iNOS antiserum raised against recombinant iNOS protein, immunohistochemical analysis was made to reveal kinetics of NO producing cells. The cells immunoreactive for iNOS appeared at 6 h post-LPS injection in the sinusoids of the liver. By structural and immunohistochemical studies, almost all iNOS positive cells were identified as Kupffer cells and endothelial cells. The number of cells immunoreactive for iNOS increased until 12 h post-LPS injection. At 24 h after LPS injection, iNOS positive cells were restricted to the foci of spotty necrosis. Hepatic injury measured by released enzymes was increased by pretreatment of L-NAME before LPS injection.

Animals↗

Hepatic denervation induces supersensitivity to terbutaline of the hepatic arterial system in conscious dogs.

The effects of hepatic denervation on liver blood flow and the influence of the denervation on the hemodynamic response to exogenously administered agents remain equivocal. This study examined the effects of the beta 2-adrenoceptor agonist, terbutaline, on liver blood flow and how these effects were influenced by surgical hepatic denervation in a conscious canine model. Two weeks after denervation, hepatic arterial flow, portal venous flow, and aortic blood flow were measured during intravenous infusion of terbutaline at 0.1, 0.2, 0.4, and 0.8 microgram/kg/min, and responses were compared between the hepatic denervated and sham-operated dogs. Implantable transit-time ultrasonic flowmeter and probes were used. Hepatic arterial flow increased dose-dependently in response to terbutaline in denervated dogs, while it remained unchanged in control dogs except at the highest dose of terbutaline. The increase in hepatic arterial flow of denervated dogs was significantly greater than that of controls at all doses of terbutaline. Aortic blood flow-indexed hepatic arterial flow in response to terbutaline also differed substantially between the two groups. Terbutaline produced a marked dose-dependent increase of portal venous flow similarly in both groups. These results suggest that the beta 2-adrenoceptor agonist terbutaline should be effective for increasing liver blood flow and could lessen postoperative liver ischemia. We speculate that hepatic denervation induces supersensitivity of the hepatic arterial system to intravenous terbutaline.

Adrenergic beta-Antagonists↗

Clinicopathologic study on pancreatic cancer associated with pancreatic stones.

Four cases of pancreatic cancer associated with pancreatic stones were investigated clinicopathologically. In Case 1, pancreatic cancer was diagnosed 2 yr 9 mo after the diagnosis of pancreatolithiasis. Numerous large stones were present throughout the pancreas, and stones in the resected specimen were embedded in the tumor. Chronic inflammation, including inflammatory infiltration and fibrosis, were found around the pancreatic duct where the stones were present, both within and adjacent to the tumor, suggesting that chronic pancreatitis had been present for a protracted period. In Cases 2-4, a few small free stones were found in the dilated pancreatic ducts and a cyst upstream from the tumor, but there were no stones noted within the tumor. Microscopically, mild atrophy of the pancreatic parenchyma and fibrosis were seen. In each of these three cases, it was considered that the pancreatic cancer was the primary event, with the pancreatic stones arising as a secondary process. The pancreatic cancers associated with pancreatic stones were classified into two groups, one with pancreatic stones preceding the pancreatic cancer and the other three cases in which the reverse occurred.

Aged↗

Distal pancreatectomy with en bloc resection of the celiac artery for carcinoma of the body and tail of the pancreas.

CONCLUSION: Combined resection of the celiac artery with a distal pancreatectomy (DP) increases the resectability and improves the overall prognosis of patients with locally advanced ductal cancer of the body and tail of the pancreas. BACKGROUND: Carcinoma of the body and tail of the pancreas is often unresectable because of invasion to adjacent organs. We evaluated a DP including an en bloc resection of the celiac artery ("extended"), for pancreatic cancer that had invaded the common hepatic and/or celiac arteries. METHODS: Six cases of an "extended" DP were compared with 19 cases of a "standard" DP for pancreatic ductal carcinoma in terms of clinical and pathologic findings, perioperative course, and long-term outcome. We also compared the survival rate of these two groups with a third group consisting of 22 patients with unresectable pancreatic ductal carcinoma. RESULTS: The mean operative time, postoperative serum aspartate aminotransferase concentration, and length of hospital stay did not significantly differ between the "extended" and "standard" DP groups. The cumulative 1- and 3-yr accumulated survival rates for the "extended," "standard," and unresectable groups were 40.0, 33.3, and 5.4, and 20.0, 16.6, and 0%, respectively. Statistically significant differences (p < 0.01) existed between the "extended" and unresected groups.

Adult↗

Hemodynamics of pancreatic ischemia in cardiogenic shock in pigs.

BACKGROUND & AIMS: Previous studies have shown that the renin-angiotensin axis plays a pivotal role in vasoconstriction of the gastric, intestinal, and hepatic circulations during cardiogenic shock. The aim of this study was to evaluate the fundamental hemodynamic mechanism of pancreatic ischemia during cardiogenic shock induced by pericardial tamponade. METHODS: Cardiogenic shock was induced by pericardial tamponade. Cardiac output (and total peripheral vascular resistance) was determined by thermodilution. Pancreatic blood flow (and vascular resistance) was determined with radiolabeled microspheres. RESULTS: Graded increases in pericardial pressure produced corresponding decreases in cardiac output to 42% +/- 1% and arterial pressure to 67% +/- 3% of baseline and increases in total peripheral vascular resistance to 146% +/- 5% of baseline. Pancreatic blood flow decreased disproportionately to 30% +/- 3% of baseline, because of a disproportionate increase in pancreatic vascular resistance to 220% +/- 19% of baseline. Previously confirmed blockade of the renin-angiotensin axis ablated this response, whereas confirmed blockade of the alpha-adrenergic system or vasopressin system had no significant effect. Without shock, central intravenous infusions of angiotensin II closely mimicked this selective vasoconstriction. CONCLUSIONS: Angiotensin-mediated selective pancreatic vasoconstriction results in significant pancreatic ischemia during cardiogenic shock.

Adrenergic alpha-Antagonists↗

Human hepatocyte growth factor in bile: an indicator of posthepatectomy liver function in patients with biliary tract carcinoma.

We measured the concentration of hepatocyte growth factor (HGF) in bile obtained from patients after hepatectomy. The HGF concentrations in the bile samples were quantified using an enzyme-linked immunosorbent assay (ELISA). By immunoblotting, using a monoclonal antibody raised against the HGF alpha-subunit, the bile HGF, which was purified on a Heparin-Sepharose column, showed a band of the same size as the recombinant HGF alpha-subunit (69 kd). Bile samples were obtained from 24 patients with biliary tract disease before and after hepatectomy by means of biliary drainage. Before surgery, the bile HGF concentrations were minimal (0.8 +/- 0.1 ng/mL); however, after hepatectomy on postoperative day 1 in patients without posthepatectomy liver failure (20 of 24), they increased severalfold (4.1 +/- 0.4 ng/mL, P < .05). The patients with posthepatectomy liver failure (4 of 24) showed no significant increase in bile HGF after hepatectomy (less than 2 ng/mL on postoperative day 1). The volume of the remnant liver correlated positively with the bile HGF concentration. The bile HGF concentration on postoperative day 1 exhibited a significant negative correlation with the maximum concentration of serum total bilirubin after hepatectomy. The concentration of bile HGF was generally higher than that in serum (2.1-fold). Thus, the bile HGF concentration after hepatectomy may be useful for the early assessment of posthepatectomy liver function.

Adult↗

Metabolic profile of high intensity intermittent exercises.

To evaluate the magnitude of the stress on the aerobic and the anaerobic energy release systems during high intensity bicycle training, two commonly used protocols (IE1 and IE2) were examined during bicycling. IE1 consisted of one set of 6-7 bouts of 20-s exercise at an intensity of approximately 170% of the subject's maximal oxygen uptake (VO2max) with a 10-s rest between each bout. IE2 involved one set of 4-5 bouts of 30-s exercise at an intensity of approximately 200% of the subject's VO2max and a 2-min rest between each bout. The accumulated oxygen deficit of IE1 (69 +/- 8 ml.kg-1, mean +/- SD) was significantly higher than that of IE2 (46 +/- 12 ml.kg-1, N = 9, p < 0.01). The accumulated oxygen deficit of IE1 was not significantly different from the maximal accumulated oxygen deficit (the anaerobic capacity) of the subjects (69 +/- 10 ml.kg-1), whereas the corresponding value for IE2 was less than the subjects' maximal accumulated oxygen deficit (P < 0.01). The peak oxygen uptake during the last 10 s of the IE1 (55 +/- 6 ml.kg-1.min-1) was not significantly less than the VO2max of the subjects (57 +/- 6 ml.kg-1.min-1). The peak oxygen uptake during the last 10 s of IE2 (47 +/- 8 ml.kg-1.min-1) was lower than the VO2max (P < 0.01). In conclusion, this study showed that intermittent exercise defined by the IE1 protocol may tax both the anaerobic and aerobic energy releasing systems almost maximally.

Adult↗

Preoperative transcatheter arterial embolization for giant cavernous hemangioma of the liver with consumption coagulopathy.

We describe a 40-yr-old woman with a giant hepatic hemangioma and consumption coagulopathy who underwent transcatheter arterial embolization (TAE) prior to liver resection. Post-contrast computed tomography showed a large mass in the right hepatic lobe with a peripheral, nodular enhancement pattern that enlarged on delayed-phase images. There was a low fibrinogen concentration and decreased platelet count. The patient received i.v. nafamostat mesilate and underwent selective embolization of the arteries feeding the hemangioma; consequently, the plasma fibrinogen concentration increased to 1.6-fold before surgery. Right hepatic lobectomy with partial resection of the caudate lobe was performed. The intraoperative blood loss was only 1380 g. This patient illustrates the usefulness of preoperative TAE for hepatic hemangioma with consumption coagulopathy; TAE appears to improve coagulopathy and increase the safety of surgery.

Adult↗

Carcinoma of the common bile duct with superficial spread to the intrahepatic segmental bile ducts: a case report.

A 54-year-old woman presented with jaundice. Percutaneous transhepatic biliary drainage, cholangiography via a percutaneous transhepatic biliary, drainage catheter, and percutaneous transhepatic cholangioscopy were performed to alleviate the jaundice and to evaluate her biliary system. A diffuse-type tumor was detected in the common bile duct. The tumor had spread superficially up to the right anterior segmental duct and the left hepatic duct and involved the caudate branches. Curative surgery, which included a right anterior segmentectomy, total caudate lobectomy, and pylorus-preserving pancreatoduodenectomy, was performed. The histopathologic diagnosis was moderately differentiated tubular adenocarcinoma originating at the common bile duct. The extent of the superficial spread of the tumor corresponded to our preoperative determination. Her postoperative recovery was uneventful. In this case report, we discuss the accurate preoperative diagnosis and rational surgical treatment of bile duct carcinoma with superficial spread.

Adenocarcinoma↗

Intravenous catecholamines alter hepatic blood flow in conscious dogs with experimental hepatic denervation.

Hepatic blood flow is regulated by the autonomic nervous system; however, blood flow through the denervated liver has been controversial. The purpose of this study is to evaluate the changes in hepatic blood flow caused by experimental hepatic denervation during the intravenous infusions of catecholamines (dopamine or dobutamine) with or without prior administration of alpha-adrenoceptor antagonist (phenoxybenzamine) or beta-adrenoceptor antagonist (propranolol). The liver blood flow was measured using transit time ultrasonic flow meter probes at the portal vein and hepatic artery in conscious dogs which (a) underwent hepatic denervation (denervation group, n = 9) and (b) were intact (control group, n = 10). Norepinephrine concentrations in the liver were determined to evaluate the effects of hepatic denervation and were decreased at 1 week and 4 weeks after hepatic denervation. In the control group, dopamine and dobutamine produced an increase of portal venous blood flow (PVF). Conversely, hepatic denervation reduced the increase in PVF by dopamine and dobutamine. Dopamine with prior administration of phenoxybenzamine produced a much larger increase in PVF in both groups. Pretreatment of propranolol in both groups abolished the increasing effects of dopamine and dobutamine in PVF. Dopamine reduced the hepatic arterial blood flow (HAF) regardless of hepatic denervation. During dobutamine infusion, HAF was decreased by hepatic denervation and prior administration of propranolol. These results suggest that hepatic denervation reduces the increasing effects of catecholamines on the hepatic blood flow through greater enhancement of alpha-adrenergic effects than of beta-adrenergic effects in the hepatic vascular autonomic nerve response.

Animals↗

Preoperative intrahepatic segmental cholangitis in patients with advanced carcinoma involving the hepatic hilus.

BACKGROUND: Major hepatic resection for biliary tract carcinoma continues to be a risky operation. In this study we examined the influence of preoperative intrahepatic segmental cholangitis on posthepatectomy mortality. METHODS: We analyzed retrospectively the clinical features of 118 patients who underwent liver resection including more than two segments for biliary tract carcinoma involving the hepatic hilus. RESULTS: Intrahepatic segmental cholangitis was encountered before operation in 22 cases. The morbidity and mortality rates for these patients were significantly higher than those of patients without preoperative cholangitis. Selective percutaneous transhepatic biliary drainage was performed before operation in 11 patients for segmental cholangitis. The morbidity rate of patients after hepatectomy was significantly lower than that of patients treated without percutaneous transhepatic biliary drainage. CONCLUSIONS: The presence of preoperative intrahepatic segmental cholangitis is a major prognostic factor in the outcome of major hepatic resection for biliary carcinoma. Selective percutaneous transhepatic biliary drainage for preoperative intrahepatic segmental cholangitis plays an important role in reducing complications after major hepatic resection.

Adult↗

Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max.

This study consists of two training experiments using a mechanically braked cycle ergometer. First, the effect of 6 wk of moderate-intensity endurance training (intensity: 70% of maximal oxygen uptake (VO2max), 60 min.d-1, 5 d.wk-1) on the anaerobic capacity (the maximal accumulated oxygen deficit) and VO2max was evaluated. After the training, the anaerobic capacity did not increase significantly (P > 0.10), while VO2max increased from 53 +/- 5 ml.kg-1 min-1 to 58 +/- 3 ml.kg-1.min-1 (P < 0.01) (mean +/- SD). Second, to quantify the effect of high-intensity intermittent training on energy release, seven subjects performed an intermittent training exercise 5 d.wk-1 for 6 wk. The exhaustive intermittent training consisted of seven to eight sets of 20-s exercise at an intensity of about 170% of VO2max with a 10-s rest between each bout. After the training period, VO2max increased by 7 ml.kg-1.min-1, while the anaerobic capacity increased by 28%. In conclusion, this study showed that moderate-intensity aerobic training that improves the maximal aerobic power does not change anaerobic capacity and that adequate high-intensity intermittent training may improve both anaerobic and aerobic energy supplying systems significantly, probably through imposing intensive stimuli on both systems.

Adult↗

Disseminated intravascular coagulation after liver resection: retrospective study in patients with biliary tract carcinoma.

BACKGROUND: Disseminated intravascular coagulation (DIC) after hepatectomy is not well understood. The objective of this retrospective study was to evaluate hemostatic changes after extensive liver resection and to elucidate the frequency of posthepatectomy DIC. METHODS: In 100 patients without cirrhosis who underwent resection of two or more segments of the liver for biliary tract carcinoma, various hemostatic parameters were measured before and after resection, and the liver function of each patient was assessed. RESULTS: In patients with posthepatectomy liver failure, platelet count, fibrinogen concentrations, and prothrombin time were significantly lower than in those without such failure. Serum levels of fibrin degradation product did not differ significantly between the two groups. The minimum platelet count was significantly negatively correlated with serum total bilirubin level. Posthepatectomy DIC occurred in 2.0% of the patients. CONCLUSIONS: After extensive liver resection patients exhibited a decreased platelet count with hepatic dysfunction. However, this condition rarely resulted in DIC, at least in patients without cirrhosis and serious postoperative complications.

Adult↗

A female infant successfully treated by ganciclovir for congenital cytomegalovirus infection.

An 11 month old female infant, diagnosed as having congenital cytomegalovirus (CMV) infection and suffering from pneumonia and intractable diarrhea, was treated with 9-(1,3-dihydroxy-2-propoxymethyl) guanine (DHPG), intravenously for 8 weeks. Watery diarrhea ceased and pneumonia associated with massive endotracheal aspirates was reduced. No leukopenia, thrombocytopenia or other side effects were observed during the therapy. The clinical findings suggest that DHPG might be an effective and safe agent for the treatment of both intestinal and lower respiratory CMV infection in young infants.

Cytomegalovirus Infections↗