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Biomedical subjects

A Morimoto

Publications and source records attributed to A Morimoto.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Optimal scan parameters of MRCP using HASTE].

For improving the image of fine structures on MRCP, optimal scan parameters were assessed by water-filled phantom using HASTE sequence. Spatial resolution and Contrast-to-Noise Ratio (CNR) were measured at various FOVs and slice thicknesses with a body array coil. High spatial resolution was provided at less than 25 cm in FOV, and narrow phantom under 1 mm in diameter was obscured at more than 30 cm in FOV. Highest CNR was provided at 3 mm slice thickness on a 1.5 T unit, and at 4 mm slice thickness on a 1.0 T unit. Narrow phantom under 1 mm in diameter was depicted clearly on a 1.5 T unit, but irregularly on a 1.0 T unit. Taking required spatial resolution and CNR into consideration, we should determine optimal FOV and slice thickness for the assessment of anatomic details on MRCP.

Biliary Tract↗
PubMed1998

[MR cholangiopancreatography using respiratory triggered half-Fourier RARE technique].

We evaluate the usefulness of MRCP using respiratory triggered HASTE technique in 68 patients. Eleven subsequent slices were obtained for MRCP. To determine the optimal trigger rate, MRCP with various trigger rates were compared in 25 patients. Respiratory triggered MRCP and breath hold MRCP were compared in 68 patients. Respiratory triggered MRCP was also performed in 3 infants. The optimal trigger rate was 10%. In 17 patients who could not stop their breath for 10 seconds, respiratory triggered MRCP were better than breath hold MRCP in 14 (82%) for the source images and in 17 (100%) for the MIP images. Respiratory triggered MRCP could depict cystic duct and main pancreatic duct even in 14 month infant. MRCP with high spatial resolution could be obtained with respiratory triggered HASTE technique in critically ill, or non-cooperative patients.

Adult↗
PubMed1997

Sodium sensitivity and cardiovascular events in patients with essential hypertension.

BACKGROUND: In patients with sodium-sensitive hypertension, glomerular pressure is increased and microalbuminuria, a marker of glomerular hypertension, is a predictor of cardiovascular events. Similarly, the lack of a nocturnal decrease in blood pressure in these patients is also associated with an increased risk of cardiovascular events. We hypothesised that sodium sensitivity may be the common factor and carried out a retrospective study of cardiovascular events in patients with essential hypertension who had had sodium sensitivity measured in our clinic. METHODS: Sodium sensitivity was assessed in about 350 patients with essential hypertension during the initial investigation of their disorder. The definition of sodium sensitivity was a 10% or greater difference in blood pressure on low-sodium or high-sodium diets. By alphabetical order, the records of 201 patients were obtained and 156 patients without pre-existing disorders were followed up. The records of patients who had a cardiovascular event or died were reviewed without knowledge of the patient's sodium-sensitivity status. FINDINGS: 62 patients were deemed sodium sensitive and 94 non-sodium sensitive. Left-ventricular hypertrophy was found more frequently in the sodium-sensitive group than in the non-sodium-sensitive group (38 vs 16%; p < 0.01), whereas significantly fewer patients in this group smoked (23 vs 42%; p < 0.05). There were 17 cardiovascular events in the sodium-sensitive group and 14 in the non-sodium-sensitive group. The rate of total, non-fatal and fatal cardiovascular events, was 2.0 per 100 patient-years in the non-sodium-sensitive group and 4.3 per 100 patient-years in the sodium-sensitive group. Cox's proportional-hazards model identified sodium sensitivity (p < 0.01), mean arterial pressure (p < 0.01), and smoking (p < 0.01) as independent cardiovascular risk factors. INTERPRETATION: Cardiovascular events occurred more frequently in patients with sodium-sensitive hypertension. Sodium sensitivity is an independent cardiovascular risk factor in Japanese patients with essential hypertension.

Adult↗
PubMed1997

Determination of farnesyl pyrophosphate in dog and human plasma by high-performance liquid chromatography with fluorescence detection.

A nonradioisotopic method has been developed for the determination of all-trans-farnesyl pyrophosphate (FPP), the common intermediate at the branch point of the biosynthesis of cholesterol and nonsterol end products, in dog and human plasma. FPP was cleaved to the parent alcohol, farnesol, by the direct addition of alkaline phosphatase to plasma. Farnesol extracted from plasma was converted into a fluorescent derivative with 9-anthroylcyanide. After the excess reagent was removed using an NH2-bonded phase cartridge, the derivative was separated by a column-switching high-performance liquid chromatographic system, followed by fluorescence detection. A linear response was obtained over the range of 2-18 ng/ml, when FPP was added to dog plasma in which the endogenous FPP concentrations had been lowered to undetectable levels by treatment with an HMG-CoA reductase inhibitor. The endogenous plasma FPP levels in the morning in dog and human detected for the first time by our method were 5.2 and 6.6 ng/ml, respectively. The method was utilized to examine the circadian rhythm of FPP in dog plasma, and different rhythms were observed between feeding and fasting dogs.

Adult↗
PubMed1997

Stimulatory effects of EGF and TGF-alpha on invasive activity and 5'-deoxy-5-fluorouridine sensitivity in uterine cervical-carcinoma SKG-IIIb cells.

We investigated the effects of epidermal growth factor (EGF) and transforming growth factor (TGF)-alpha on migration, invasion and matrix metalloproteinase (MMP) expression of uterine cervical-carcinoma SKG-IIIb cells, and whether these growth factors affect pyrimidine-nucleoside-phosphorylase (PyNPase) activity and 5'-deoxy-5-fluorouridine (5'-dFUrd) sensitivity of tumor cells. Tumor-cell migration along a gradient of substratum-bound fibronectin and invasion into reconstituted basement membrane were stimulated by 0.1 to 100 ng/ml of EGF and TGF-alpha in a concentration-dependent manner. The zymography of tumor-conditioned medium showed that the treatment of tumor cells with EGF and TGF-alpha resulted in an increase of the 92-kDa type-IV collagenase (MMP-9), which was confirmed by immunoblot analysis. These growth factors also up-regulated the expression of PyNPase activity of tumor cells and consequently enhanced the anti-proliferative action of 5'-dFUrd, a cytostatic that is biotransformed to 5-fluorouracil (5-FUra) by PyNPase. However, EGF and TGF-alpha did not have significant effects on the 5-FUra sensitivity of tumor cells. These results suggest that EGF and TGF-alpha, tumor environmental factors, simultaneously up-regulate the potential of uterine cervical-carcinoma cells to invade extracellular matrices and their PyNPase activity, which are subsequently associated with the specific action of 5'-dFUrd selectively killing tumor cells of gynecological origin with high invasive and metastatic potential.

Basement Membrane↗
PubMed1997

Effect of exercise on plasma adrenomedullin and natriuretic peptide levels in myocardial infarction.

1. We investigated the effect of exercise on plasma adrenomedullin, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) concentrations and studied the relationship between these peptides and haemodynamic parameters in nine patients with old myocardial infarction (MI) and in eight normal subjects. 2. The exercise protocol consisted of two fixed work loads (40 and 80 W) for 4 min each and venous blood samples were taken at rest, during each exercise stage and after exercise while monitoring the mean arterial pressure (MAP) and heart rate (HR). In MI, pulmonary arterial pressure (PAP), pulmonary capillary wedge pressure (PCWP), left ventricular end-diastolic pressure (LVEDP) and cardiac output (CO) were measured throughout exercise. 3. Adrenomedullin levels did not significantly increase with exercise. Adrenomedullin levels correlated with PAP and PCWP at rest (P < 0.05). Atrial natriuretic peptide levels correlated with PAP, PCWP and LVEDP throughout exercise (P < 0.05) but, on multiple regression analysis, PCWP correlated only with ANP (P < 0.01). Brain natriuretic peptide levels correlated with LVEDP throughout exercise (P < 0.01) and its increment correlated closely with basal BNP levels at rest (P < 0.01). 4. These results suggest that adrenomedullin does not respond to the acute haemodynamic changes of exercise, whereas ANP responds to it and PCWP is the major stimulus factor. Brain natriuretic peptide responds to exercise in proportion to the basal synthesis of BNP in patients with left ventricular dysfunction and LVEDP may play a role in increasing BNP during exercise.

Adrenomedullin↗
PubMed1997

Effect of additives on dissolution and swelling of soybean lecithin microcapsules prepared using the Wurster process.

Microcapsules whose membranes contained soybean lecithin (SL), cholesterol (CH), stearic acid (SA) and polyvinylpyrrolidone (PVP) at various compositions were prepared. Then, dissolution and swelling behaviors of the microcapsules in a 0.9% saline solution were studied to be related to the phase diagram of three components containing 42% of PVP in anhydrous state. In the aqueous solution, when an anhydrous microcapsule membrane was composed of SL not saturated with both CH and SA, the microcapsules showed rapid release of carbazochrome sodium sulfonate (CCSS, a model drug), poor particle-swelling and spouting of droplets containing CCSS. Long-delayed release of CCSS and drastic particle-swelling with no spouting of droplets were observed when the anhydrous membrane was composed of SL saturated with both CH and SA and the composition was not close to the two-component line, CH-SA, or to the saturation line. The spouting of droplets would be attributable to the CH and/or SA-poor SL phase and to the SL phase which dissolved CH and SA, but contained either CH or SA only in a small amount, and the delayed release would be due to the CH and SA-rich SL phase dissolving a great amount of CH and SA formed by hydration. The degree of release suppression and particle-swelling depended on the SL content. At 20-45% of SL content, the prolonged-release, great particle-swelling and no spouting of droplets at the early stage were observed only when the CH and SA-rich SL phase formed by hydration contained a high content of CH and SA.

Adrenochrome↗
PubMed1997

Different secretion patterns of adrenomedullin, brain natriuretic peptide, and atrial natriuretic peptide during exercise in hypertensive and normotensive subjects.

The purpose of this study was to investigate the effect of exercise on plasma concentrations of adrenomedullin, brain natriuretic peptide (BNP), and atrial natriuretic peptide (ANP) in patients with essential hypertension (n = 15) and in normotensive controls (n = 10). Exercise consisted of two fixed workloads, 40 and 80 watts of work load using a supine bicycle ergometer. Plasma levels of all three peptides at rest were significantly higher in hypertensives than in controls. Plasma concentrations of ANP increased with exercise in both groups and had greater increments in hypertensive patients than in normotensives. Plasma concentrations of BNP increased only in patients with hypertension and the levels of increase correlated with basal plasma BNP levels (r = 0.94, p < 0.001) and with left ventricular mass (r = 0.62, p < 0.01) determined by echocardiography. In contrast, plasma adrenomedullin did not change with exercise in either group. These results suggest that secretion patterns of these peptides are regulated by different mechanisms and that the amount and kind of peptides mobilized by exercise may depend on the underlying diseases or pathophysiologic condition.

Adrenomedullin↗
PubMed1996

Relationship between left ventricular geometry and natriuretic peptide levels in essential hypertension.

Previous studies have shown that plasma levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are increased in essential hypertension. However, whether left ventricular geometry affects plasma ANP and BNP levels remains unknown. To investigate the effect of left ventricular geometry on plasma ANP and BNP levels in essential hypertension, we measured plasma ANP and BNP levels in 90 patients with essential hypertension. All patients were hospitalized, and fasting blood samples were obtained in the early morning after 30 minutes of bed rest. Plasma ANP and BNP levels were measured by immunoradiometric assay. Hypertensive patients were classified into four groups according to echocardiographic findings that showed normal geometry, concentric remodeling, eccentric hypertrophy, or concentric hypertrophy. Mean plasma ANP and BNP levels in all essential hypertensive patients were higher than those in age-matched normotensive control subjects. Plasma ANP levels in hypertensive patients with concentric remodeling, eccentric hypertrophy, and concentric hypertrophy were higher than in normotensive control subjects, although there were no differences between normotensive subjects and hypertensive patients with normal geometry. Plasma BNP levels tended to be higher in hypertensive patients with normal geometry, concentric remodeling, and eccentric hypertrophy than in normotensive control subjects; however, the differences were not significant. Plasma BNP levels and BNP/ANP ratio were specifically higher in concentric hypertrophy. There were significant correlations between ANP and left ventricular mass index, relative wall thickness, interventricular septal thickness, posterior wall thickness, and mean arterial pressure. Plasma BNP levels significantly correlated with relative wall thickness, interventricular septal thickness, posterior wall thickness, and left ventricular mass index but not with mean arterial pressure. In addition, plasma BNP levels were well correlated with ANP levels, and the slope for the linear regression model was steeper in concentric hypertrophy than in the other four groups. These results show that plasma ANP and BNP levels are increased in essential hypertensive patients with left ventricular hypertrophy. Furthermore, BNP secretion is augmented to a greater extent in concentric hypertrophy. Thus, measurement of plasma ANP and BNP levels may be useful for the detection of concentric left ventricular hypertrophy in patients with essential hypertension.

Adult↗
PubMed1995

Suppression of interleukin-1 beta production in the circumventricular organs in endotoxin-tolerant rabbits.

Interleukin-1 beta (IL-1 beta) production in the brain and the spleen was investigated in rabbits which show febrile tolerance to bacterial endotoxin, lipopolysaccharide (LPS). Febrile tolerance to LPS was induced by daily intravenous (i.v.) injections of LPS (4 micrograms/kg, i.v.) for 5 days. In the LPS-tolerant rabbits, the second phase of the biphasic fever induced by i.v. injection of LPS (4 micrograms/kg) disappeared, although the first phase remained intact. In situ hybridization and immunohistochemical studies revealed that IL-1 beta production was observed in the circumventricular organs, such as the organum vasculosum laminae terminalis (OVLT), subfornical organ (SFO) and area posterema (AP), 1 h after the first exposure to i.v. injection of LPS (4 micrograms/kg) (acute rabbits). In contrast, IL-1 beta production in these circumventricular organs disappeared in the LPS-tolerant rabbits. IL-1 beta production was observed in the spleens of the acute and the LPS-tolerant rabbits after i.v. injections of LPS. The cells which produced IL-1 beta in the spleen following LPS injections were confirmed to be monocytes/macrophages and polymorphonuclear leukocytes by immunohistochemistry in both the acute and the LPS-tolerant rabbits. The LPS-injected acute rabbits showed a significant increase in the number of IL-1 beta-immunoreactive monocytes/macrophages, compared with that in the saline-injected acute rabbits. However, there was no significant difference in immunoreactive cell numbers between the saline-injected acute and LPS-injected tolerant rabbits, or between the LPS-injected acute and the LPS-injected tolerant rabbits.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

A unique case of renovascular hypertension caused by combined renal artery disease.

We present a unique case of renovascular hypertension due to combined renal artery disease in a 22-year-old woman. Renal angiography revealed renal artery stenosis with poststenotic dilatation and an aneurysm due to fibromuscular dysplasia in the left kidney, and a congenital arteriovenous fistula in the right kidney. The results of a captopril test and plasma renin sampling demonstrated that the renin-angiotensin-aldosterone system was stimulated in both kidneys, accounting for the hypertension in this patient. Almost all cases of renovascular hypertension are due to only one underlying renal artery disease. This is the first case of renovascular hypertension associated not only with renal artery stenosis and an aneurysm due to fibromuscular dysplasia, but also with a congenital arteriovenous fistula.

Adult↗
PubMed1995

[Transjugular intrahepatic portosystemic shunt for patients with hepatoma].

Nine patients with hepatoma, 5 with massive ascites, 3 with rupture of esophageal varices and 1 with hematoemesis, successfully underwent TIPS without technical complications. Two of the patients died 3 and 5 months, respectively, after TIPS due to hepatic failure and/or tumor extension. Another patient in whom hepatoma ruptured 1 month after TIPS was experienced. It is concluded that TIPS is a useful and safety treatment for portal hypertension even in patients with hepatoma which was not existed through the puncture route. However TIPS should be performed in patients in whom hepatoma has been controlled by hepatic embolization and/or ethanol injection therapy.

Aged↗
PubMed1995

[Transrectal portal scintigraphy for evaluation of portal hemodynamics before and after TIPS].

In order to evaluate portal venous hemodynamics before and after TIPS, transrectal portal scintigraphy was performed in 8 patients. In all 8 patients, scintigram before TIPS demonstrated hepatofugal flow in the portal vein and less accumulation of radioisotope in the liver. In the scintigrams for follow-up of TIPS, the flow direction in the portal vein changed to be hepatopedal. In 3 of the patients in whom stent shunt was occluded after TIPS, the portal blood flow was turned to be hepatofugal again. It is concluded that transrectal portal scintigraphic studies of the TIPS patients provide noninvasive evaluation of portal hemodynamics.

Aged↗
PubMed1995

[Anesthesia for funnel chest operation].

The incidence of perioperative complication and days of hospital stay were studied in 56 patients with funnel chest operation under inhalational anesthesia (18 cases), intravenous anesthesia (23 cases) and epidural anesthesia (15 cases). Perioperative complication occurred most frequently in the inhalational group and was followed by intravenous and epidural group. Postoperative hospitalization on an average was 21.4 days in the inhalational group, 21.9 days in the intravenous group and 16.7 days in the epidural group. It is said that postoperative pain leads to splinting of the chest, which can cause atelectasis and/or pneumonia. Severe postoperative pulmonary complication was reduced in the epidural groups. As a result, hospitalization in the epidural group was shorter than in other groups. This study suggests that epidural anesthesia is more advantageous for funnel chest operation because epidural anesthesia has protective action against arrhythmia and postoperative pulmonary complication.

Adolescent↗
PubMed1994

[MR pyelography using fast spin echo technique in hydronephrosis].

MR pyelography using the fast spin echo technique and and a body coil were performed in ten patients with hydronephrosis. In all cases, pyelograms of the dilated urinary tract were obtained by this method, although they were obtained in only two cases by drip infusion pyelography. MR pyelography is an effective method with which to obtain images of dilated urinary tract non-invasively, and in a relatively short time. This method was also useful to evaluate intraureteral structure.

Adolescent↗
PubMed1994

Characterization of the rabbit intestinal fructose transporter (GLUT5).

Recent studies suggest that the jejunal/kidney-type facilitative glucose transporter (GLUT5) functions as a high-affinity D-fructose transporter. However, its precise role in the small intestine is not clear. In an attempt to identify the fructose transporter in the small intestine, we measured fructose uptake in Xenopus oocytes expressing jejunal mRNA from five species (rat, mouse, rabbit, hamster and guinea-pig). Only jejunal mRNA from the rabbit significantly increased fructose uptake. We also cloned a rabbit GLUT5 cDNA from a jejunal library The predicted amino acid sequence of the 487-residue rabbit GLUT5 showed 72.3 and 67.1% identity with human and rat GLUT5 respectively. Northern-blot analysis revealed GLUT5 transcripts in rabbit duodenum, jejunum and, to a lesser extent, kidney. After separation of rabbit jejunal mRNA on a sucrose density gradient, the fractions that conferred D-fructose transport activity in oocytes also hybridized with rabbit GLUT5 cDNA. Hybrid depletion of jejunal mRNA with a GLUT5 antisense oligonucleotide markedly inhibited the mRNA-induced fructose uptake in oocytes. Immunoblot analysis indicated that GLUT5 (49 kDa) is located in the brush-border membrane of rabbit intestinal epithelial cells. Xenopus oocytes injected with rabbit GLUT5 cRNA exhibited fructose uptake activity with a Km of 11 mM for D-fructose. D-Fructose transport by GLUT5 was significantly inhibited by D-glucose and D-galactose. D-Fructose uptake in brush-border membrane vesicles shows a Km similar to that of GLUT5, but was not inhibited by D-glucose or D-galactose. Finally, cytochalasin B photolabelled a 49 kDa protein in rabbit brush-border-membrane preparations that was immunoprecipitated by antibodies to GLUT5. Our results suggest that GLUT5 functions as a fructose transporter in rabbit small intestine. However, biochemical properties of fructose transport in Xenopus oocytes injected with GLUT5 cRNA differed from those in rabbit jejunal vesicles.

Amino Acid Sequence↗
PubMed1994

[Usefulness of MR cholangiography with flex coil].

Fast SE MR cholangiography was performed in 10 healthy volunteers and 10 patients with biliary disease, using body, shoulder and flex coils. Surface coils provided better images than the body coil. Although high SNR images were obtained near surface coils, signal intensity decreased in areas distant from the shoulder coil. The flex coil greatly improved image quality, especially in intrahepatic bile ducts, compared with the shoulder coil. The application of a flex coil to MR cholangiography is a highly useful method to evaluate the biliary system.

Adult↗