Biomedical subjects

T Ohta

Publications and source records attributed to T Ohta.

At least 613 records · Page 34Linked to original sources

PubMed1995

Effects of lansoprazole on pharmacokinetics and metabolism of theophylline.

The effect of the new substituted benzimidizole proton pump inhibitor, lansoprazole, on pharmacokinetics and metabolism of theophylline has been studied in healthy adults given oral lansoprazole 30 mg once daily for 11 days. On Days 4 and 11 of 300 mg aminophylline was simultaneously administered orally and blood samples for theophylline analysis were taken over 24 h. Urine samples were collected for up to 24 h and were assayed for theophylline and its major metabolites 1,3-dimethyluric acid (1,3-DMU), 1-methyluric acid (1-MU) and 3-methylxanthine (3-MX). The pharmacokinetic parameters of theophylline were determined, and the urinary recovery of unchanged theophylline and its major metabolites were calculated. After administration of lansoprazole for 4 days, no significant alteration in the terminal elimination half-life (t1/2beta) or the mean resistance time (MRT) was detected. However, there was a significant decrease of about 13% in the area under the plasma concentration-time curve (AUC) and a significant increase of about 19% in the apparent clearance (CLapp). Lansoprazole treatment for 11 days caused a significant decrease of approximately 12% in t1/2beta and about 10% in the MRT of theophylline, although neither AUC nor CLapp showed a significant alteration. The excretion of 3-MX in the urine was significantly increased by about 20% after lansoprazole treatment for 4 and 11 days, although there was no significant alteration in the excretion of unchanged theophylline, 1,3-DMU or 1-MU. The results indicate that repeated administration of lansoprazole to humans induces the hepatic microsomal P-450-dependent drug oxidation system that mediates N-1-demethylation of theophylline, consequently increasing its metabolism.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed1995

Low dose phenytoin is an osteogenic agent in the rat.

Long-term use of phenytoin for the treatment of epilepsy has been associated with increased thickness of craniofacial bones. The aim of the present study was to evaluate the possibility that low doses of phenytoin are osteogenic in vivo by measuring the effects of phenytoin administration on serum and bone histomorphometric parameters of bone formation in two rat experiments. In the first experiment, four groups of adult male Sprague-Dawley rats received daily I.P. injections of 0, 5, 50, or 150 mg/kg/day of phenytoin, respectively, for 47 days. Serum alkaline phosphatase (ALP) and osteocalcin were increased by 5 and 50 mg/kg/day phenytoin. The increases in osteocalcin and ALP occurred by day 7 and day 21, respectively. The tibial diaphyseal mineral apposition rate (MAR) at sacrifice (day 48) was significantly increased in rats receiving 5 mg/kg/day phenytoin. At a dose of 150 mg/kg/day, the increase in serum ALP, osteocalcin and MAR was reversed. No significant differences in serum calcium, phosphorus, or 1,25(OH)2D3 levels were seen. In a second experiment, three groups of rats received daily I.P. injection of lower doses of phenytoin (i.e., 0, 1, or 5 mg/kg/day, respectively) for 42 days. Phenytoin also did not affect the growth rate or serum calcium, phosphorus, and 25(OH)D3 levels. Daily injection of 5 mg/kg/day phenytoin significantly increased several measures of bone formation, i.e., serum ALP and osteocalcin bone ALP, periosteal MAR, and trabecular bone volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗

PubMed1995

Phenytoin and fluoride act in concert to stimulate bone formation and to increase bone volume in adult male rats.

We have recently demonstrated that phenytoin is an osteogenic agent at low doses. The present paper describes observations that a mitogenic dose (i.e., 20 microM in BGJb medium) of fluoride significantly augments the phenytoin-dependent stimulation of normal human bone cell proliferation and alkaline phosphatase (ALP) activity in cell culture. Additionally, the present study was designed to investigate whether fluoride and phenytoin would interact to increase bone formation in rats in vivo. Four groups of weight-matched adult male rats received daily I.P. injection of (1) vehicle (10% DMSO), (2) 5 mg/kg/day phenytoin, (3) 5 mg/kg/day phenytoin and 50 ppm NaF, and (4) 50 ppm NaF and vehicle, respectively, for 36 days. Sodium fluoride (NaF) was delivered in drinking water. Blood samples were drawn weekly and analyzed for serum osteocalcin, ALP, calcium, phosphorus, and 25(OH)D3. Rats were labeled with tetracycline at day 21 and 30 and histomorphometric analysis was carried out on the tibia at the end of the experiment. Neither agent by itself or together affected the serum calcium, phosphorus, or 25(OH)D3 levels. All measures of bone formation, i.e., serum osteocalcin level and ALP activity, bone ALP specific activity, mineral apposition rate, bone formation rate, and % bone formation surface, were increased by each agent. Fluoride and phenytoin together produced bigger increases in each parameter than did each agent alone. Trabecular bone volume was increased in the tibial metaphysis by fluoride or phenytoin alone; and when administered together, the two agents produced a greater increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗

PubMed1995

A new method of performing continuous intraabdominal drainage after pancreaticoduodenectomy.

Dehiscence of the pancreaticoenterostomy is one of the most feared, yet common, postoperative complications following pancreaticoduodenectomy (PD). We report herein a new technique we developed for performing continuous intraabdominal suction drainage (CISD) following PD. This method of CISD involves positioning an 18 Fr sump tube beside the pancreaticoenterostomy, with a continuous suction pressure of about -20cmH2O. The fluid obtained from the sump tube is also useful for monitoring amylase levels and providing bacterial cultures to enable the early detection of dehiscence of pancreaticoenterostomy. A study was conducted on 150 patients who underwent PD for periampullary carcinoma over a 20-year period. The patients were divided into two groups according to whether or not CISD was performed: group 1 comprised 71 patients who had CISD, and group 2 79 patients who did not have CISD. Although the frequency of anastomotic dehiscence did not differ between the two groups (32% in group 1 and 25% in group 2), the mortality rate of the patients with anastomotic leakage in group 1 was lower than that in group 2 (P = 0.07). Thus, we believe that our new technique for performing CISD could improve the surgical outcome of patients following PD.

Abdomen↗

PubMed1995

Benefits of arterial reconstruction in claudication.

We conducted a midterm follow-up of 150 claudicants who underwent surgical reconstruction by assessing cumulative patency, survival, and palliation (graft patency in live patients) rates. Eighty-nine claudicants (group I) underwent direct (in situ) proximal revascularization, 33 (group II) had indirect (ex situ) proximal revascularization, while 28 (group III) had distal revascularization. The secondary patency rates at 3 years were 97.5% in group I, 97.0% in group II, and 75.0% in group III, respectively. Only one patient with limb graft thrombosis required below-knee amputation. There were 3 perioperative deaths (2 in group I and 1 in group II). The survival rates at 3 years were 86.0% in group I, 69.5% in group II, and 95.8% in group III, respectively. The palliation rates at 3 years were 84.8% in group I, 70.0% in group II, and 77.9% in group III, respectively. These findings indicate the midterm benefits of supra- and infrainguinal arterial reconstructions, and also suggest that the preoperative assessment of risks in individual patients, the selection of the appropriate operative procedure and graft material, and intensive postoperative follow-up and management of any associated disease are all important aspects in the treatment of claudicants.

Aged↗

PubMed1995

Serial MRI in early Creutzfeldt-Jacob disease with a point mutation of prion protein at codon 180.

We report a 66-year-old woman with histologically diagnosed Creutzfeldt-Jacob disease (CJD), followed with MRI from an early clinical stage. MRI demonstrated expansion of the high cortical signal on T2-weighted images, which differs from previous MRI reports of CJD. This patient followed an atypical clinical course: 16 months had passed before she developed akinetic mutism, and periodic sharp waves had not been detected on EEG after 2 years in spite of her akinetic mutism. Brain biopsy showed primary spongiform changes in the grey matter, and a point mutation of the prion protein gene at codon 180 was discovered using polymerase chain reaction direct sequencing and Tth 111 I cutting. This is the first case with the point mutation of the codon 180 variant with an atypical clinical course and characteristic MRI findings.

Aged↗

PubMed1995

Simulation study on bypass and therapeutic occlusion in the posterior circulation.

A hydraulic vascular model of the vertebrobasilar artery with an autoregulatory mechanism was constructed. The haemodynamic effect of superficial temporal artery (STA)-posterior cerebral artery (PCA) bypass was investigated in cases of bilateral vertebral artery (VA) occlusion and basilar artery (BA) occlusion. Assuming therapeutic BA occlusion for basilar bifurcation aneurysms, the flow volume through the P1 segment of the PCA was determined in relation to diameters of the posterior communicating artery (PCom). The bypass increases both flow volume and intraluminal pressure in the presence range below 60 mm Hg, while it increases only pressure in the autoregulatory range above 60 mm Hg. Its haemodynamic effect is more marked in BA occlusion than in VA occlusion. The averaged values of the increase in flow volume are 29.0 +/- 4.3% (mean +/- SD) and 16.5 + 1.0%, respectively. The total flow volume increase of the vertebrobasilar system is usually lower than the flow volume measured at the bypassed STA. The difference between the two is equal to the simultaneous decrease in flow volume through the PComs. Flow volume through the P1 segment can be expressed as a function of the PComs diameter ratio squared. A hydraulic simulation study will be useful for speculating on the haemodynamic effects of these operative procedures.

Basilar Artery↗

PubMed1995

Significance of ST segment elevation in electrocardiograms in patients with ruptured cerebral aneurysms.

Twenty-three patients with aneurysmal subarachnoid haemorrhage (SAH), who showed an ST segment elevation in their electrocardiograms (ECG), were examined. There were 12 males and 11 females, with a mean age of 61 years. The clinical condition on admission was Hunt and Kosnik grade II in four, III in seven, IV in one, and V in 11 patients. Computerized tomography (CT) also revealed many cases of diffuse, thick SAH or intracerebral or intraventricular haematoma. Laboratory examinations including serum electrolyte, pH, and PaO2 revealed no abnormalities that might have influenced the ECG. Elevation in the levels of myocardial enzymes in serum was observed in two of the nine patients examined, although the elevation was only slight in one of them. Echocardiography, which was performed on several occasions on all patients, and cardiac catheterization, which was performed on eight patients, revealed a reduction in the motion of the left ventricular apex that was synchronous with ST segment elevation. This is the first report about these phenomena. No abnormalities were observed in the coronary artery. The elevated ST segment was normalized within one week in all patients, accompanied by normalization of the apical wall motion recorded on echocardiograms. In four patients, however, T wave inversion accompanied the improvement of the ST segment and was normalized within three months after the onset. These results suggest that ST segment elevation in the acute stage of SAH reflects transient cardiac dysfunction rather than myocardial injury. In some patients, however, the elevated serum levels of myocardial enzymes or T wave inversion suggested the presence of myocardial injury. Close follow-up seems to be necessary in such cases.

Adult↗

PubMed1995

Stereo-videomicrography projection system for use at scientific meetings. A technical note.

A new stereoscopic projection system has been developed for simultaneous viewing of microsurgical procedures by hundreds of participants at neurosurgical meetings. The video images recorded from each eyepiece of an operating microscope were projected onto two wide screens, which were viewed by two converging eyes or by cross-sight. The system was simple and proved to be of great practical use although it yielded minor eyestrain and required some practice.

Equipment Design↗

PubMed1995

A case of macrocystic serous cystadenoma of the pancreas.

A case of macrocystic serous cystadenoma of the pancreas is presented, and literature is reviewed. A 35-yr-old woman presented with mild upper abdominal pain. Abdominal ultrasonography and an abdominal computed tomography revealed a multiloculated and calcified cyst in the body of the pancreas. A T1-weighted image, using magnetic resonance imaging, revealed a low-intensity multiloculated, pancreatic mass. In contrast, T2-imaging of the tumor showed a high-intensity mass. Endoscopic retrograde cholangiopancreatography showed no contact between the main pancreatic duct and the tumor. The preoperative diagnosis was a mucinous cystic neoplasm. Tumor enucleation was performed. Subsequent microscopic examination of this tumor suggested the diagnosis of a macrocystic serous cystadenoma of the pancreas.

Adult↗

PubMed1995

Phases of the cell cycle sensitive to endoreduplication induction in CHO-K1 cells.

We investigated the sensitive phase of the cell cycle for endoreduplication induction by colchicine, vanadate, 4-nitroquinoline 1-oxide (4NQO), and hydrazine in Chinese hamster CHO-K1 cells, compared to the metaphase endoreduplication inducer rotenone. Treatment of asynchronous cultures and 5-bromodeoxyuridine (BrdU) labeling analysis showed that the detected endoreduplications originated from cells which had been treated with these inducers in S, G2, or metaphase. Exposure to synchronized metaphase cells revealed that the inducers did not lead metaphase cells to endoreduplicate. These results were markedly different from that of rotenone and suggested that the target for the induction of endoreduplication by the tested compounds existed between at least S and G2 phases.

4-Nitroquinoline-1-oxide↗

PubMed1995

Expression of pancreatic trypsinogen/trypsin and cathepsin B in human cholangiocarcinomas and hepatocellular carcinomas.

We evaluated in situ expression of pancreatic trypsinogen (PT) and cathepsin B (CB) in 10 normal livers, 37 cholangiocarcinomas (CCs), and 36 hepatocellular carcinomas (HCCs). In normal livers, PT was expressed in intrahepatic large bile ducts, septal bile ducts, and peribiliary glands, and CB was present in hepatocytes and all epithelial cells of the intrahepatic biliary system. In CCs, PT was present in 26 (70%), of which 24 expressed PT both in CC cells and the CC stroma, and the remaining two showed PT only in CC cells. The ratio of PT-positive cases was high in well-differentiated CCs, moderate in moderately differentiated CCs, and low in poorly differentiated CCs. PT in the CC stroma was present in continuity with PT-positive CC cells, suggesting that PT was secreted from CC cells. The CC stroma positive for PT frequently showed destructive features. CB was present in 32 CCs (86%) and located in both CC cells and the CC stroma. All PT-positive CCs simultaneously expressed CB, suggesting a close association of PT and CB. In HCCs, in contrast, PT was not present in any cases. CB was present in 33 HCCs (92%) and located in both HCC cells and the HCC stroma. In positive specimens, PT immunoreactivity was finely granular in the cytoplasm, whereas CB immunoreactivity was diffuse in the entire cytoplasm. These data suggest that after malignant transformation CCs and HCCs continue to express PT and CB, and CB, respectively. It seems possible that PT secreted from CC cells is converted into trypsin by CB, and that trypsin and CB play a role in CC invasion by degrading extracellular matrix proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1995

Traumatic basilar impression: case report.

A very rare case of traumatic basilar impression is reported. The patient, a 57-year-old man, was hit on the head vertically in the parietal region. X ray of the cervical spine and computed tomography (CT) scans showed intracranial indentation of the atlas and the odontoid process with a depressed fracture around the foramen magnum. There are no previous reports about this type of fracture.

Cranial Fossa, Posterior↗

PubMed1995

Chopstick penetration of the posterior cranial fossa: case report.

A very rare case of wooden foreign body intrusion into the posterior cranial fossa is reported. The patient, a 16-month-old girl, fell down while holding chopsticks and was injured in the right pre-auricular region. Computed tomographic scans revealed a linear low-density area ranging from the right external auditory meatus to the fourth ventricle through the petrous portion of the temporal bone, passing near the middle cerebellar peduncle. Right temporal craniotomy was performed to abrade the petrous bone, resulting in removal of the chopstick fragment. The patient had an uneventful postoperative course and was discharged in ambulant condition, only with right hearing difficulty.

Accidental Falls↗

PubMed1995

Geographical variations in mutagenicity of blue rayon extracts of Japanese human bile.

The mutagenicity of human bile was investigated in the Ames test after blue rayon treatment. In the present study, 52 and 59 bile samples were collected from the high and the low risk population for gallbladder cancer (GBC), respectively. The bile mutagenicity was detected only when the blue rayon extracts of bile were assayed with Salmonella typhimurium TA98 in the presence of S9 mix. Thirty-two (61.5%) of 52 samples obtained from the high risk population were mutagenic. In our previous study (Mano et al., 1993), the mutagenicity was observed in 14 (58.3%) of 24 samples. After combining this data with the results of the present study, 46 (60.5%) of 76 samples revealed the mutagenicity. On the other hand, the mutagenicity was detected in only 7 (11.9%) of 59 samples collected from the low risk population. Therefore, we found a significant geographical difference in the bile mutagenicity.

Adult↗

PubMed1995

Effect of dietary linoleic acid on the tryptophan-niacin metabolism in streptozotocin diabetic rats.

To make clear the mechanism of change of tryptophan-niacin metabolism in diabetic rats, we investigated the effect of dietary linoleic acid on the tryptophan-niacin metabolites and the activity of liver, alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase (ACMSD), a key enzyme of tryptophan-niacin metabolism, in streptozotocin diabetic rats. Moreover, we investigated the involvement of linoleic acid in the induction of hepatic ACMSD activity by streptozotocin diabetes. In diabetic rats, the sum of urinary excretion of nicotinamide, N1-methylnicotinamide (MNA), N1-methyl-2-pyridone-5-carboxamide (2-Py) and N1-methyl-4-pyridone-3-carboxamide (4-Py) was higher in the fat free diet group than in the linoleic acid group, that was accompanied by the increase of tryptophan intake and reduction of body weight in the fat free diet group. In diabetic rats, hepatic ACMSD activity was higher in the fat free diet group than in the linoleic acid group. The results indicated that the induction of hepatic ACMSD activity by diabetes was not due to removal of the suppressive effect of the linoleic acid on the enzyme. In the diabetic+insulin group, hepatic ACMSD activity was significantly lower than in the diabetic group.

Animals↗

PubMed1995

Characteristics of ATP-induced catecholamine secretion from adrenal chromaffin cells of the guinea-pig.

The effect of ATP on catecholamine secretion and intracellular Ca2+ concentration ([Ca2+]i) was examined using perfused adrenal glands and dispersed chromaffin cells of the guinea-pig. The application of ATP (2 to 10 mM) for 2 min caused a dose-dependent increase in catecholamine secretion from perfused adrenal glands. ADP, but neither AMP nor adenosine, was also effective in increasing catecholamine secretion, though its potency was much less than that of ATP. 3. The ATP-induced secretory response was observed even under Na(+)-deficient conditions, but was reversibly abolished by removal of extracellular Ca2+. 4. In dispersed chromaffin cells, ATP (0.5 mM) caused increases in catecholamine secretion and [Ca2+]i, both of which were abolished after the removal of extracellular Ca2+. 5. These results indicate that ATP released from adrenal chromaffin cells together with catecholamine may exert a positive feedback influence on the following exocytotic catecholamine secretion. This effect may be accomplished by increasing the entry of extracellular Ca2+, but not by mobilizing intracellular Ca2+ stores in adrenal chromaffin cells of the guinea-pig.

Adenine Nucleotides↗

PubMed1995

Left ventricular function on exercise after surgical treatment of small aortic annuli.

To evaluate left ventricular function during exercise after aortic annular enlargement 15 patients with either aortic (group I, n = 8) or aortomitral (group II, n = 7) annuloplasty for small aortic annuli and eight patients (group III) with standard valve replacement for aortic stenosis without small aortic annuli received gated cardiac pool imagining by technetium-99m-labelled red blood cells at rest and during exercise at a mean of 23 months after operation. Left ventricular ejection fraction, preload requitable stroke work and stroke power index (preload requitable stroke work/systolic ejection period) were measured. Compared with resting values, left ventricular performance and stroke work rate on exercise after aortic annular enlargements increased significantly, as did those after standard aortic valve replacement. These results suggest that aortic annular enlargement can be indicated for surgical treatment of valvular heart diseases associated with small aortic annuli.

Adult↗