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Biomedical subjects

Hiroaki Yasuda

Publications and source records attributed to Hiroaki Yasuda.

10 recordsLinked to original sources
PubMed2005

Measurement of cerebral reserve capacity using acetazolamide loading xenon CT CBF before carotid endarterectomy.

BACKGROUND AND PURPOSE: Brain swelling and/or hemorrhage can occur after carotid endarterectomy. This phenomenon is called the hyperperfusion syndrome. Several factors contribute to this syndrome. One is reperfusion in a maximally dilated vessel which means disappearance of cerebral reserve capacity (CRC). The aim of the study was to determine whether CRC measurement was useful for intraoperative and postoperative management of carotid endarterectomy. PATIENTS AND METHODS: We studied 64 cases (male 53, female 11), 49-79 years. CRC was measured preoperatively using acetazolamide loading Xenon CT CBF examination (XeCT). Hypothermia (34-35 C) was induced during surgery in a patient with no CRC. Anesthesia was maintained the night after surgery and the systolic blood pressure was controlled below 120 mmHg. RESULTS: CRC was absent in 10 patients. Postoperative CT did not reveal any hemorrhage or brain swelling. One patient experienced a transient restless state. DISCUSSION: and conclusions: Cerebral hyperperfusion syndrome has been reported in 0.3 approximately 6.0% of patients following carotid endarterectomy (vs 1.6% in our study without hemorrhage or brain swelling). These data suggest that information on CRC could be useful for selection and perioperative management of patients during carotid endarterectomy.

Acetazolamide↗
PubMed2005

Notch 2-positive progenitors with the intrinsic ability to give rise to pancreatic ductal cells.

Pancreatic adenocarcinomas display foci of duct-like structures that are positive for markers of pancreatic ductal cells. The development of these tumors is promoted by conditions leading to acinar-to-ductal metaplasia, a process by which acinar cells are replaced by ductal cells. Acinar-to-ductal metaplasia has recently been shown to proceed through intermediary cells expressing Nestin. To create an in vitro system to study pancreatic adenocarcinomas, we had used an hTERT cDNA to immortalize primary cells of the human pancreas. In this report, we show that the immortalized cells, termed hTERT-HPNE cells, have the ability to differentiate to pancreatic ductal cells. Exposing hTERT-HPNE cells to sodium butyrate and 5-aza-2'-deoxycytidine lead to the formation of pancreatic ductal cells marked by the expression of MDR-1, carbonic anhydrase II, and the cytokeratins 7, 8, and 19. hTERT-HPNE cells were found to have properties of the intermediary cells formed during acinar-to-ductal metaplasia, which included their undifferentiated phenotype, expression of Nestin, evidence of active Notch signaling, and ability to differentiate to pancreatic ductal cells. These results provide further evidence for the presence in the adult pancreas of a precursor of ductal cells. hTERT-HPNE cells should provide a useful model to study acinar-to-ductal metaplasia and the role played by this process in pancreatic cancer development.

Adenocarcinoma↗
PubMed2004

Solid pseudopapillary tumor as a possible cause of acute pancreatitis.

CONTEXT: Acute pancreatitis is not commonly seen in the first presentation of pancreatic neoplasms. Solid pseudopapillary tumor as a cause of acute pancreatitis has not yet been reported. This is the first report of acute pancreatitis resulting from solid pseudopapillary tumor. CASE REPORT: We report the case of a 21-year-old female who presented with a sudden onset of severe abdominal pain associated with elevated serum pancreatic enzyme concentration. The initial diagnosis was acute pancreatitis. However, subsequent ultrasonography and computed tomography showed an abdominal mass in the tail of the pancreas, retroperitoneal fluid and left pleural effusion. There was scarce pain relief even with large doses of analgesics. A distal pancreatectomy was then performed and a final diagnosis of solid pseudopapillary tumor was made histologically. The surrounding pancreatic tissue was characterized as hemorrhagic edematous pancreatitis. CONCLUSIONS: Solid pseudopapillary tumor is generally known as a slow-growing pancreatic neoplasm with few, if any, symptoms. However, solid pseudopapillary tumors should be kept in mind as a possible cause of acute pancreatitis, especially in cases of non-alcoholic young women having an acute pancreatitis attack.

Acute Disease↗
PubMed2004

Increased QT dispersion in patients with alcoholic pancreatitis.

OBJECTIVES: Increased dispersion of the QT interval has been proposed to be a novel marker for increased risk of ventricular arrhythmia and sudden cardiac death. This study examined whether QT dispersion is affected in patients with alcoholic pancreatitis. METHODS: We measured the QT interval, corrected QT interval, activation recovery interval, activation time, recovery time, and their respective dispersions in 3 age- and gender-matched groups: patients with alcoholic pancreatitis [age, 58.9 +/- 11.8 years; male/female (M/F), 33/3], patients with alcohol dependence (age, 59.3 +/- 8.9 years; M/F, 33/4), and a healthy control group (age, 55.8 +/- 8.8 years; M/F, 33/3). RESULTS: The QT dispersions in patients with alcoholic pancreatitis (62.4 +/- 19.9 milliseconds; P < 0.001) or alcohol dependence (58.2 +/- 19.6 milliseconds; P < 0.001) were significantly greater than in the control group (41.4 +/- 13.3 milliseconds). Similarly, the corrected QT dispersions in patients with alcoholic pancreatitis (68.5 +/- 22.8 milliseconds; P < 0.001) or alcohol dependence (65.3 +/- 23.6 milliseconds; P < 0.001) were significantly greater than in the control group (42.8 +/- 13.2 milliseconds). Both QT dispersion and QTc dispersion were longer in patients with alcoholic pancreatitis than those with alcohol dependence (P = 0.011 and P = 0.039, respectively). Simple linear regression analysis of the relationship between the RR and QT intervals revealed that the regression lines for patients with alcoholic pancreatitis and alcohol dependence were almost parallel. However, the slope of the regression line for the control group was significantly greater (P < 0.05) than for the other 2 lines. CONCLUSION: The findings demonstrate increased QT and QTc dispersions in patients with either alcoholic pancreatitis or alcohol dependence. The QT dispersion and QTc dispersion were longer in patients with alcoholic pancreatitis than those with alcohol dependence.

Arrhythmias, Cardiac↗
PubMed2004

[Role of apoptosis in severe acute pancreatitis].

The role of apoptosis in a severe acute pancreatitis is recently given the most attention, but it is hardly known in a clinical study. We show three assumptions between apoptosis and the pathophysiological mechanisms of severe acute pancreatitis in this paragraph. First, the apoptosis of pancreatic acinar cell might prevent from a worsening in acute pancreatitis due to diminish leakage of pancreatic enzyme and extension of inflammation. Secondly, impairment cellular immunity due to peripheral lymphocyte apoptosis might be linked to the development of subsequent infectious complications in acute pancreatitis. Third, apoptosis in various major organs might be involved in the mechanism of multiple organs failure in acute pancreatitis. These findings might lead the new development in the therapeutic strategy of acute pancreatitis.

Acute Disease↗
PubMed2003

[Vertebral artery occlusion following neck trauma: report of two cases].

We are reporting two cases of vertebral artery occlusion resulting from cervical spine trauma. A 41-year-old man experienced vertigo and nausea 6 hrs after chiropractic manipulation. On admission, he was alert and demonstrated nystagmus, hypalgia of left leg, and right Horner sign. A MR image revealed infarction in the right cerebellar hemisphere. A MR angiogram did not show the proximal part of the right vertebral artery. A right vertebral angiogram revealed right vertebral artery occlusion at the level of C 1. He underwent anticoagulation and wore a cervical collar. He was discharged with hypalgia of left leg. A 53-year-old man was admitted to our hospital after an automobile accident. A CT scan revealed a subarachnoid hemorrhage and an intraventricular hemorrhage. A cervical CT scan revealed fractures of the C 5 facet joint and C 6 vertebral body. A MR angiogram did not show the proximal part of the left vertebral artery. A subsequent left vertebral angiogram revealed left vertebral artery occlusion at the level of C 6. He underwent anticoagulation and wore a cervical collar. In addition, he underwent coil embolization of the left vertebral artery. He was discharged with no neurological deficits. It is said that traumatic vertebral artery injuries cause cerebral infarction with time lags. The therapeutic point is to prevent propagation of the thrombus and distal embolism; therefore wearing a collar, anticoagulation, and endovascular interventional therapy is recommended.

Accidents, Traffic↗
PubMed2002

Severe cerebral blood flow reduction inhibits nitric oxide synthesis.

The purpose of this study was to investigate the relationship between cerebral blood flow (CBF) and nitric oxide (NO) synthesis using a rat model of transient forebrain ischemia of varying severity. Forebrain ischemia was induced for 30 min by occlusion of the bilateral common carotid arteries without hemorrhagic hypotension. The production of NO end-products (nitrite and nitrate) was measured by in vivo microdialysis, and CBF by the hydrogen clearance technique. Ischemia induced NO synthesis, although the increase in the quantity of NO end-products was not remarkable during the ischemic period but became prominent after reperfusion. Such increases were abolished by Nomega-nitro-L-arginine methyl ester (L-NAME), although 7-nitroindazole (7-NI) appeared to have only slight effects. The production of NO end-products during ischemia increased when the CBF during ischemia was less than 60 mL/100 g/min. In animals in which the CBF during ischemia was higher than 22.7 mL/100 g/min, the production of NO end-products increased gradually after the induction of ischemia and reached a peak during the reperfusion period, whereas in other animals in which the CBF during ischemia fell below 22.7 mL/100 g/min, the NO end-products decreased during ischemia and increased transiently after reperfusion. These results suggest that the increase in NO end-products is NO synthase (NOS)-dependent and that most of the increase is derived from endothelial NOS. It is also suggested that NO synthesis during ischemia is closely related to CBF, and that severe CBF reduction may inhibit NO synthesis.

Animals↗
PubMed2002

Relation between morphologic changes in the main pancreatic duct and exocrine pancreatic function after a secretin test.

INTRODUCTION: Because pancreatic exocrine function testing methods are problematic, both imaging and functional tests are important in the diagnosis of chronic pancreatitis. AIM: To evaluate the usefulness of ultrasonographic monitoring of the main pancreatic duct after a secretin test. METHODOLOGY: A total of 70 subjects (30 control subjects, 26 patients with probable chronic pancreatitis, and 14 patients with definite chronic pancreatitis) were selected. The main pancreatic duct diameters were measured serially after an injection of secretin (100 IU/body). The relation between the magnitude of the duct dilation and exocrine pancreatic function on the secretin test was evaluated. RESULTS: The main pancreatic duct dilated immediately after a bolus injection of secretin, showed a peak after 2-5 minutes, and recovered gradually. The response curve of the definite group had a flatter pattern than that of the other groups. For the maximal to basal duct diameter ratio, statistically significant differences were found between the control and definite groups and between the control and probable groups. In addition, the ratio correlated significantly with the maximal bicarbonate concentration and secretory volume on the secretin test. CONCLUSIONS: The results of the current study indicate that exocrine pancreatic function and the morphologic changes of the main pancreatic duct are significantly related. Dynamic ultrasonographic findings may reflect pancreatic function; consequently, this test may be a useful tool in the diagnosis of chronic pancreatitis.

Adult↗