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Biomedical subjects

M Miyazaki

Publications and source records attributed to M Miyazaki.

At least 1,279 records · Page 71Linked to original sources
PubMedDate not supplied

Mechanism of cold ischemia-reperfusion-induced graft injury after orthotopic liver transplantation in rats.

BACKGROUND/AIMS: The purpose of this study was to clarify the mechanism of cold ischemia-reperfusion-induced graft injury after liver transplantation, especially with regard to the relationship between hepatocyte, sinusoidal endothelial cell injury, and hepatic hemodynamic alteration. METHODOLOGY: We evaluated changes in hepatocyte and sinusoidal endothelial cell function, and hepatic hemodynamics after reperfusion in an isogeneic rat liver-transplantation model. The livers of male LEW rats were stored in 4 degrees C lactated Ringer's solution for 1 hr, 3 hr (viable graft), and 6 hr (nonviable graft) before implantation. After reperfusion, hepatocyte function was assessed by serum alanine aminotransferase level and bile output; sinusoidal endothelial cell function was evaluated by serum hyaluronic acid level. Furthermore, we measured hepatic venous oxygen saturation, and portal venous blood flow using a transit time blood flow meter. RESULTS: At 2 hr after reperfusion, the hepatocyte function was similar in all groups. However, the sinusoidal endothelial cell function deteriorated severely in the nonviable graft group, and significantly decreased hepatic venous oxygen saturation levels were observed, suggesting poor hepatic circulation. At 4 hr after reperfusion, the hepatocyte injury was markedly increased in the nonviable graft group. Although systemic blood pressure remained stable, significantly decreased portal venous blood flow in the nonviable graft group was found compared with the viable graft groups. Histopathological studies showed that massive ischemic necrosis was seen in zone III (central) of hepatic lobule 8 hr after reperfusion in the nonviable graft group. CONCLUSIONS: These data suggest that the sinusoidal endothelial cell injury was predominant in the early phase of reperfusion, and might cause microcirculatory disturbances, resulting in decreased portal venous blood flow. This phenomenon may subsequently cause ischemic damage to the hepatocyte, with eventual graft failure.

Animals↗
PubMedDate not supplied

Enhanced expression of cyclin E and cyclin A in human hepatocellular carcinomas.

BACKGROUND: Disruption of the G1/S check point leads to uncontrolled cell growth, resulting in the development of cancers. MATERIALS AND METHODS: Cell cycle regulatory molecules were investigated in 33 surgically resected hepatocellular carcinoma (HCC) samples from 30 patients by Western blotting. RESULTS: Enhanced expressions of cyclin E and cyclin A were detected at frequencies of 18/33 and 26/33 in HCCs, respectively, as compared with their neighboring noncancerous tissues. The enhanced expression of cyclin E, but not that of cyclin A, correlated with hyperphosphorylation of pRb and high frequency of Ki-67-positive cells. Thus, the HCCs with enhanced cyclin E expression probably contain a relatively large number of proliferating cancer cells. CONCLUSIONS: The degree of cyclin E expression can be used as a prognostic parameter of HCC. In addition, cyclin E may become a molecular target in the treatment of HCCs.

Aged↗
PubMedDate not supplied

An approach to intrapericardial inferior vena cava through the abdominal cavity, without median sternotomy, for total hepatic vascular exclusion.

In surgical resection for hepatocellular carcinoma with tumor thrombus extending into the inferior vena cava and other malignancies involving the retrohepatic inferior vena cava, the usefulness of total hepatic vascular exclusion has been reported by several authors. Total hepatic vascular exclusion usually consists of clamping at three points; at the infrahepatic inferior vena cava, at the suprahepatic inferior vena cava, and in Pringles' maneuver. Tumor thrombus extending into the inferior vena cava at the intrapericardial level below the right atrium can be resected without the use of cardio-pulmonary bypass. The inferior vena cava at the intrapericardial level has been reported to be usually approached by median sternotomy such as Chevron incision. We herein demonstrate an approach to the intrapericardial inferior vena cava through the abdominal cavity without median sternotomy.

Aged↗
PubMedDate not supplied

Adhesion of single application bonding systems to bovine enamel and dentin.

Single application bonding systems have recently been developed in an effort to simplify and shorten bonding procedures. This study compared their bonding ability to enamel and dentin. Four commercial single application systems, Reactmer Bond (Shofu Inc), One-Up Bond F (Tokuyama Co), AQ Bond (Sun Medical Co, Japan) and Prompt L-Pop (ESPE, Germany) were used. F2000 compomer (3M Dental Products, St Paul, MN 55144, USA) was used as a control material. Bovine mandibular incisors were mounted in self-curing resin and the facial surfaces were ground to expose either enamel or dentin. Restoratives were bonded after adhesive application to tooth surface according to the manufacturer's instructions. Fifteen samples per test group were stored in 37degrees C water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/minute. Statistical analysis was accomplished with a one-way ANOVA followed by the Duncan test (p<0.05) were done. The enamel bond strengths of the newly developed one step bonding systems were not significantly different from the compomer except for Prompt L-Pop, which showed the highest value. The dentin bond strengths of single application bonding systems did not differ from the compomer. The results of this study suggest that the adhesive properties of the newly developed single application bonding systems were comparable to a compomer restorative.

Adhesiveness↗
PubMedDate not supplied

Carboplatin AUC and gamma-glutamylcysteine synthetase gene expression in peripheral mononuclear cells of lung cancer patients.

BACKGROUND: To investigate the association between glutathione-related enzymes and carboplatin (CBDCA) dose, we examined gene expression levels for both subunits of gamma-glutamylcysteine synthetase (heavy; gamma-GCSh, light; gamma-GCS1) in peripheral mononuclear cells (PMN) of lung cancer patients before and after CBDCA administration. MATERIALS AND METHODS: PMN and plasma samples were obtained from 10 advanced non-small lung cancer patients before and after CBDCA administration. We analyzed the gene expression levels by reverse transcription-polymerase chain reaction. RESULTS: Gamma-GCSh expression levels in PMN increased within 24 hours after CBDCA administration, whereas gamma-GCS1 expression levels did not. However, the actual area under the concentration curve (AUC) of CBDCA did not correlate with gamma-GCSh expression at 24 hours or the increased ratio of gamma-GCSh expression in PMN. CONCLUSION: Expression of gamma-GCSh is induced by CBDCA, however, CBDCA AUC is not a determinant for the increased expression levels of gamma-GCSh in PMN.

Antineoplastic Agents↗
PubMedDate not supplied

Age-dependent change in the response of isolated beagle cerebral arteries to vasoactive agents.

Responses to vasoactive agents were compared in helical strips of cerebral arteries from beagles of different ages (30 days, 3 months, 1 year, and 3 years old). Contractile responses to norepinephrine, serotonin, and histamine, relative to those induced by 30 mM K+, were greater in the infant (30-day-old) beagle arteries than in those from the older beagles. Angiotensin II-induced contractions did not differ in these arteries, whereas relaxations induced by the peptide, converted to contractions by indomethacin, were greater in the arteries from adult beagles than in the immature beagle arteries. Relaxations induced by nicotine, due to stimulation of vasodilator nerves, and those induced by a small amount of K+, mediated by activation of the electrogenic Na+ pump, were not dependent on age. Infant beagle cerebral arteries responded to prostacyclin (PGI2) with a greater relaxation, whereas isoproterenol produced greater relaxations in the adult beagle arteries. It may be concluded that the sensitivity or the quantity of alpha 2-adrenergic and H1-histaminergic receptors is high in the cerebral arteries of infant beagles and declines with age; the affinity of serotonergic receptors decreases with age. Biosynthesis of PGI2 in the vascular wall appears to increase with age. Functions of the vasodilator nerve innervating large cerebral arteries and of the electrogenic Na+ pump in muscle cell membranes may mature during the fetal or early postpartum period and, thereafter, are maintained unaltered.

Acetylcholine↗
PubMedDate not supplied

Heterogeneous responses to vasodilators of dog proximal and distal middle cerebral arteries.

Responses to various vasodilators were compared in helical strips of proximal and distal middle cerebral arteries isolated from the same dogs, which were partially precontracted with prostaglandin (PG) F2 alpha or K+. Nicotine-induced relaxations, selectively blocked by hexamethonium, were greater in the proximal than in the distal portion, whereas K+ (5 mM)-induced relaxations, reversed to contractions by ouabain, were greater in the distal portion. Angiotensin II and PGI2 relaxed distal middle cerebral arteries to a greater extent; the difference in relaxations induced by the octapeptide in large and small arteries was more evident. Relaxations induced by isoproterenol and adenosine were greater in distal arteries; in contrast, those induced by nitroglycerin were greater in proximal arteries. Acetylcholine and verapamil relaxed the arteries of both portions to a similar extent. It may be concluded that proximal middle cerebral artery functions are regulated by dilator nerves more intensely than the distal artery functions, and the electrogenic Na+ pump in cell membrane of distal middle cerebral arteries leaves more room for being activated under the experimental conditions used. Angiotensin II appears to liberate more PGI2 from the distal cerebral arteries.

Acetylcholine↗
PubMedDate not supplied

Electrogastrography in neonates.

We recorded the electrical signals from bipolar electrodes placed on the abdomen of 7 adults and 10 newborn infants. Data were analyzed by visual inspection and by a wave analysis computer program with a fast Fourier transform. Waves of 3 cycles/min were recorded in adults, and similar 3 cycles/min waves were recorded in infants as well. The percentage of time of 3 cycles/min waves was lower in neonates (13.8% +/- 10.8%) than in adults (57.9% +/- 27.8%) (p < 0.01). Only an electrocardiogram superimposing the flat baseline was recorded in the remaining recording time. Spectral analysis confirmed the validity of the visual analysis, showing clear peaks at 0.05 Hz only when 3 cycles/min waves were visually present and motion artifact was absent. The electrode positions where percentage of time of 3 cycles/min waves was greatest were different for newborns and adults. There was no significant difference in the mean amplitude of the waves between groups. These facts indicate that the electrogastrogram of neonates is different from that of adults in terms of best electrode positions and percentage of time of 3 cycles/min waves.

Adult↗
PubMedDate not supplied

Influence of irradiation sequence on dentin bond of resin inlays.

The relationship between the order in which a dual-cured resin cement is light activated and the bond strength of resin inlay materials to dentin was examined. Also evaluated was the setting time with various irradiation sequences. Lite-Fil CR/Imperva Bond (Shofu) and Clearfil CR/CR Cement (Kuraray) were employed. Ten specimens, 4 mm in diameter by 4 mm deep, were made with each material for each condition and bonded to bovine dentin with the respective bonding agent and cement. Order of light activation was: 1) no light activation; 2) premix activation of only the liquid prior to mix, 3 seconds for Lite-Fil and 25 seconds for Clearfil; 3) postplacement activation, 30 seconds for Lite-Fil and 40 seconds for Clearfil; and 4) premix and postplacement activation, 3 seconds and 30 seconds for Lite-Fil and 25 seconds and 40 seconds for Clearfil. Samples were stored in water for 24 hours and shear strength tested. The setting time with no activation and premix activation was measured according to the ISO #7489 standards. Bond strengths (MPa) were 1) 4.41, 2) 13.07, 3) 6.34, and 4) 14.81 for Lite-Fil, and 1) 0.37, 2) 2.44, 3) 0.52, and 4) 2.51 for Clearfil. No light activation or only postplacement activation resulted in lower bond strengths with a 4.0 mm-thick specimen. The setting time of the cement mix with premix activation was shorter than with no activation. Light activation of these dual-cure cements is essential. Premix activation of only the liquid resulted in bond strengths similar to those obtained with combined pre- and postplacement activating.

Analysis of Variance↗
PubMedDate not supplied

A successful treatment for hepatocellular carcinoma with atrial tumor thrombus.

A 66-year-old man with an advanced hepatocellular carcinoma and tumor thrombus extending into the right atrium was treated by transcatheter arterial infusion of lipiodol and aclarubicin. This brought about a remarkable reduction of the tumor and the disappearance of the right atrial tumor thrombus. The tumor was then radically resected by hepatic posterior segmentectomy with combined resection of the right hepatic vein, where the tumor thrombus remained. He is doing well without any signs of recurrence 22 months after the operation.

Aclarubicin↗
PubMedDate not supplied

Influence of dentin primer application methods on dentin bond strength.

This study was carried out to determine the influence of dentin primer application methods on bond strength to human dentin. Two dentin bonding restorative systems, Imperva Bond/Lite-Fil II A (Shofu) and Scotchbond Multi-Purpose/Z-100 (3M) were employed. Human molars were mounted in self-cured resin and the buccal surfaces were prepared with #600-grit SiC paper. These surfaces were then conditioned according to each manufacturer's instructions. Two experiments were designed: (1) effect of the primer application procedures (inactive and active application), and (2) effect of the air drying time (0, 1, 5, 10, 20, and 30 seconds). The adhesives were applied and resin composites were bonded to the teeth. Ten samples per test group were stored in 37 degrees C deionized water for 24 hours, and shear tested with a circular knife edge at a crosshead speed of 1.0 mm/minute. A one-way ANOVA followed by the Newman-Keuls multiple comparison at P < 0.05 was done. For both restorative systems, the bond strengths for active application were higher than those for inactive application, but there was no significant difference between the two mean values. According to the air drying time, there appeared to be an optimal range of drying times, longer for Imperva Bond (10-30 seconds) than for Scotchbond MP (1-5 seconds). The data suggest that the bond strengths of employed dentin bonding systems were greatly influenced by the methods of the dentin primer application.

Air↗
PubMedDate not supplied

Nonpalpable breast cancer with nipple discharge: how should it be treated?

In this study, 26 cases of nonpalpable breast cancer with nipple discharge treated at our department were reviewed. Their discharge was either bloody or serous with a positive hematest, but all except for one were negative for cytology, while CEA value of the discharge was high in 72.7%. Mammograms were found to be unreliable for diagnosis, while abnormal findings were observed in 84.6% by ductography. However, final diagnosis was determined histopathologically from surgical specimens, showing 14 intraductal and 12 invasive ductal cancers, none with components of comedo carcinomas. Seventeen patients underwent mastectomy following duct-lobular segmentectomy and a small remnant of intraductal carcinoma was found microscopically in only one patient. All patients except for one have survived for 98 months on average with no symptoms of metastasis. These findings suggest that duct-lobular segmentectomy with an adequate surgical margin should be adopted as the final operation for selected patients with nonpalpable breast cancer involving nipple discharge.

Adult↗
PubMedDate not supplied

Effects of biliary obstruction on hepatic deoxyribonucleic acid and protein synthesis after partial hepatectomy.

BACKGROUND/AIMS: Major hepatectomy for biliary malignancy associated with biliary obstruction is often complicated due to hepatic failure. To determine the effects of biliary obstruction on liver regeneration, hepatic deoxyribonucleic acid and protein synthesis after partial hepatectomy was studied in rats with pre-operative biliary obstruction. MATERIALS AND METHODS: After 5 or 14 days of biliary obstruction, experimental rats underwent concurrent biliary decompression and 70% partial hepatectomy. Control rats underwent partial hepatectomy alone. Hepatic deoxyribonucleic acid synthesis was determined 24 hours after partial hepatectomy. Hepatocellular protein synthesis and secretory protein synthesis were determined at baseline and 48 hours after partial hepatectomy. RESULTS: Deoxyribonucleic acid synthesis was significantly depressed in rats with biliary obstruction compared with controls (p < 0.05). Baseline hepatocellular protein synthesis and secretory protein synthesis, especially secretory protein synthesis, increased in proportion to the duration of biliary obstruction (p < 0.01). After partial hepatectomy, control rats showed marked increases in hepatocellular protein synthesis and secretory protein synthesis (p < 0.01). Increased baseline hepatocellular protein synthesis and secretory protein synthesis were preserved in the regenerating liver of rats with biliary obstruction. CONCLUSIONS: The results suggest that biliary obstruction gives priority to secretory protein synthesis over DNA synthesis which may inhibit liver regeneration.

Alanine Transaminase↗
PubMedDate not supplied

Vascular reconstruction using left renal vein graft in advanced hepatobiliary malignancy.

BACKGROUND/AIMS: In surgical resection for advanced hepatobiliary malignancies involving the portal vein and inferior vena cava, vascular reconstruction is usually required. We utilized left renal vein grafts for vascular reconstruction in cases of these malignancies, and their clinical significance is evaluated in this study. METHODOLOGY: Left renal vein grafts were utilized for reconstruction of the portal vein in four patients and patch repair of the inferior vena cava was performed in two patients with advanced hepatobiliary malignancies. All six patients underwent hepatic resection with vascular resection and reconstruction. Postoperative renal function and graft patency were assessed. RESULTS: Transient slight renal disturbances appeared in some patients, but there was no severe renal dysfunction requiring specific therapy. Graft patency was maintained during the follow-up period in all patients. CONCLUSION: The use of left renal vein grafts as autovein grafts seems appropriate in cases involving reconstruction of the portal vein and in those involving patch repair of the inferior vena cava defect in surgical resection for advanced hepatobiliary malignancies.

Adult↗