Search PubMed⌕ Search

Biomedical subjects

S Ueda

Publications and source records attributed to S Ueda.

At least 469 records · Page 26Linked to original sources
PubMed1994

A CMOS integrated circuit for multichannel multiple-subject biotelemetry using bidirectional optical transmissions.

A CMOS integrated circuit for a noninvasive biological-signal telemetry system specified for use in medical and physiological studies of the influence of weightlessness in space is presented. The system can monitor multichannel (4 channels maximum) biological signals from multiple subjects (4 subjects maximum) in real time by using time multiplexing. A key technique, so-called synchronized multiple-subject telemetry, to achieve multiple-subject telemetry has been proposed. This technique utilizes bidirectional optical transmissions with direct and scattered infrared lights between an observer and each of the subjects. An experimental CMOS IC to give a small light-weight low-power, and smart telemetry instrument for use on animals has been developed. This IC is for evaluating circuit blocks of the implantable monolithic telemetry instrument. The major circuit blocks include CMOS digital circuits for synchronization, subject selection and time multiplexing, analog circuits for pulse interval modulation (PIM), and other blocks such as a CMOS optical pulse receiver and an LED driver. A preliminary experimental multichannel telemetry from two subjects has been performed with the implemented IC chips, and the principal operation of the multiple-subject optical biotelemetry has been demonstrated.

Aerospace Medicine↗
PubMed1994

Addition of cisapride shortens colonoscopy preparation with lavage in elderly patients.

METHODS: The effect of pre-treatment with cisapride on colonoscopy preparation with lavage solution was compared in 120 out-patients less than 60 years and 73 out-patients 60 years or older, who were scheduled for total colonoscopy. By random allocation, patients were assigned to receive cisapride 10 mg or placebo 30 minutes before ingesting the magnesium citrate lavage solution. RESULTS: The cleansing results and patients' acceptance did not differ significantly in the two treatment groups in either age group. The time from the start of ingesting magnesium citrate until the rectal effluent became clear was significantly shorter in cisapride-treated patients of 60 years or more. Moreover, the residual fluid volume removed by suction during colonoscopy was significantly less in the patients above aged 60 years who received cisapride. CONCLUSION: These findings indicate that the combination of cisapride and magnesium citrate is more effective than magnesium citrate alone in cleansing the colon for colonoscopy in elderly patients.

Adult↗
PubMed1994

Enhanced arterial intimal thickening after balloon catheter injury in diabetic animals accompanied by PDGF beta-receptor overexpression of aortic media.

Cultured aortic smooth muscle cells (SMC) of diabetic rats and rabbits, which overexpress platelet-derived growth factor (PDGF) beta-receptor compared with controls, have a unique phenotype. In this study we report on the PDGF beta-receptor overexpression in aortas of diabetic animals and the increased intimal thickening of carotid arteries in diabetic rabbits after balloon catheter injury compared with that in controls. In diabetic aortas with no treatments of balloon catheter injury, intimal thickening was not observed in spite of the overexpression of PDGF beta-receptor, indicating that the growth property of medial SMC in diabetic aortas was changed before the intimal thickening could take place. PDGF is known to be the main contributor to the intimal thickening induced by balloon catheter injury, which is one of several forms of arterial injuries. Intimal thickening after balloon catheter injury in diabetic rabbits increased compared with that in controls. These results imply that PDGF beta-receptor overexpression of SMC in medial layers plays an important role in intimal thickening in the formation of advanced diabetic macroangiopathy.

Animals↗
PubMed1994

Effects of pyridoxalated hemoglobin polyoxyethylene conjugate and stroma-free hemoglobin on renal vascular responsiveness to vasoactive substances in isolated perfused rat kidney.

The effects of pyridoxalated hemoglobin polyoxyethylene conjugate (PHP) and stroma-free hemoglobin (SFH) on vascular responsiveness to various vasoactive substances were examined in isolated perfused rat kidneys. The kidneys isolated from rats were perfused with 6% PHP, 6% SFH, and 6% hydroxyethylstarch (HES) solution at a constant flow rate. Vascular responsiveness to acetylcholine (ACh), nitroglycerin (NG), norepinephrine (NE), and angiotensin-II (ANG-II) was examined by measuring the perfusion pressure (PP). Effects of inhibition of endothelium-derived relaxing factor (EDRF) by NG-monomethyl L-arginine (L-NMMA) on NE-induced and ANG-II-induced renal vascular responses were examined. ACh and NG induced a dose-dependent decrease in perfusion pressure (PP) in all groups. NE and ANG-II induced an increase in PP in all groups, but NE-induced and ANG-II-induced responses in the PHP-perfused and SFH-perfused groups were significantly larger than those in the HES-perfused group. L-NMMA did not alter vascular responsiveness to NE and ANG-II. These results indicate that PHP and SFH do not inhibit EDRF induced by ACh, but hemoglobin moiety per se does augment the vascular responsiveness to NE and ANG-II in the isolated perfused rat kidney.

Acetylcholine↗
PubMed1994

Seroepidemiology of hepatitis C virus infection in Japan and HCV infection in haemodialysis patients.

Since January 1990, Japanese Red Cross Blood Centres have introduced hepatitis C virus screening with a first-generation ELISA. From April to December 1992, approximately 0.98% among 10,905,489 blood donations screened by a second-generation assay were anti-HCV-positive in all Japan. Seropositivity of anti-HCV increased with the age and serum transaminase value in both sexes. In blood donors having a history of transfusion, the anti-HCV reactive rate was 7.4%. The results of the study made by the Japanese Red Cross Non-A, Non-B Hepatitis Research Group show the effectiveness of implementation of HCV screening to prevent posttransfusion hepatitis. Consecutive haemodialysis patients with chronic renal failure are at risk for infection by a variety of blood-borne agents transmitted within dialysis units. Because of their immunocompromised state, they frequently also have an unusual susceptibility to a variety of nosocomial infections, such as HBV, HCV, and HTLV-I. We tested the prevalence of anti-HCV in 1423 (848 males and 575 females) haemodialysis patients from 18 hospitals in Kumamoto Prefecture, Japan, using the Ortho first generation anti-HCV screening assay. There were 316 patients (22.2%) positive for HCV antibodies. The second-generation test was positive in most haemodialysis patients who were reactive to the first-generation assay. The prevalence of HCV infection increased with the duration of haemodialysis, yet there was a high frequency of HCV seropositivity even without blood transfusion. Acquisition of HCV in dialysis patients could be explained by HCV infection within the unit other than by blood (all haemodialysis are done with disposable kits, syringes, and needles), by secondary HCV infection after the immunodeficiency of haemodialysis, or by HCV infection of the kidney or glomerular deposition of immune HCV/anti-HCV complexes leading to chronic renal failure (as with HBV infection of the liver and kidney.

Blood Donors↗
PubMed1994

Protection against the mouse-adapted A/FM/1/47 strain of influenza A virus in mice by a monoclonal antibody with cross-neutralizing activity among H1 and H2 strains.

The monoclonal antibody designated C179 was found to neutralize all of the H1 and H2 strains of influenza A virus studied (Y. Okuno, Y. Isegawa, F. Sasao, and S. Ueda, J. Virol. 67:2552-2558, 1993). In the present study, the ability of C179 to protect mice from the lethal effect of the A/FM/1/47 (H1N1) strain was examined. When the mice were injected intraperitoneally with 100 micrograms of C179 per mouse a day before the virus challenge (2.0 x 10(3) focus-forming units per mouse), all of the mice survived. Moreover, significantly higher survival rates were observed in mice receiving 1,000 micrograms of C179 per mouse 2 days after the virus challenge than in those receiving phosphate-buffered saline alone. These results indicate that C179 is effective not only for prevention but also for treatment of mice infected with H1 and H2 strains. The possibility that C179 can be used for passive immunization in humans is discussed.

Amino Acid Sequence↗
PubMed1994

pH-dependent multilamellar structures in fetal mouse bone: possible involvement of fatty acids in bone mineralization.

pH-dependent multilamellar structures in fetal mouse bone: possible involvement of fatty acids in bone mineralization. Am. J. Physiol. 266 (Cell Physiol. 35): C590-C600, 1994.--Multilamellar structures (MLS) were found inside and outside osteoblasts in cultured and uncultured fetal mouse parietal bone fixed at pH 7.3 with glutaraldehyde solution containing tannic acid (TA). Electron-lucent areas (up to 1.5 microns in diameter) surrounded by thin lamellar structures were found in place of MLS in bone and bone cell cultures fixed at pH 6.0 in the presence of TA. Large lipid droplets were found, in place of electron-lucent areas and MLS, in specimens fixed at pH 7.4 in the absence of TA and dehydrated with a procedure that did not extract neutral lipid. Freeze-fracture studies showed phosphatidylcholine formed MLS at both pH 8.1 and pH 6.0, whereas oleic acid formed MLS at pH 8.1 and lipid droplets at pH 6.0. Thus fatty acids probably formed the pH-dependent MLS found in bone. The data suggest that osteoblasts synthesize and secrete fatty acids, as droplets, into the extracellular space. The close association of MLS with calcifying osteoid in specimens processed with TA suggests that fatty acids are directly involved in bone mineralization.

Animals↗
PubMed1994

Regional assignment of the human immunoglobulin processed pseudogene C epsilon 3 (IGHEP2) to 9p24.2-->p24.1 by fluorescence in situ hybridization.

The human immunoglobulin processed pseudogene C epsilon 3 (IGHEP2), which was assigned to chromosome 9 by somatic cell hybrid analysis, has not been regionally localized as yet. In this study, using fluorescence in situ hybridization (FISH) combined with conventional QFQ-, RBG- or GTG-banding, IGHEP2 was assigned to the p terminus region of chromosome 9, at band 9p24.2-->p24.1. This result suggests that the C epsilon 3 gene is a novel telomeric DNA marker useful not only for constructing the physical map of human chromosome 9 but also for cytogenetic analyses such as cryptic translocations. In addition, comparative mapping of this gene in other catarrhine primates would contribute to investigations of human and other primate karyotype evolution.

Cells, Cultured↗
PubMed1994

The complete sequences of African horsesickness virus serotype 4 (vaccine strain) RNA segment 2 and 6 which encode outer capsid protein.

The complete sequences of RNA segment 2 and segment 6 of African horsesickness virus serotype 4 (AHSV-4) vaccine strain were determined from cDNA clones inserted into pBR 322. The RNAs of segment 2 and 6 are 3229, 1566 bp long respectively and both contain an open reading frame encoding proteins VP2 and VP5 of 1060, 505 amino acid residues. The estimated molecular weight of VP2 was 124,178 dalton and that of VP5 was 56,793 dalton. Their noncoding end sequences were 5'GTTTAA . . . and . . . ACATAC3' (segment 2), 5'GTTTAT . . . and . . . ACTTAC3' (segment 6). They were different from orbivirus characteristic terminal sequences, which were 5'GTTAAA . . . and . . . ACTTAC3'. The comparison of both sequences of AHSV-4 segment 2 and 6 with those of segment 2 and 5 of bluetongue virus (BTV) serotype 10 revealed 53% nucleotide similarity and 23% amino acid similarity (segment 2), and 58% nucleotide similarity and 46% amino acid similarity (segment 6). In the same way, the comparison of both sequences of the vaccine strain with those of the virulent strain segment 2 and segment 6 of AHSV-4 revealed 91% nucleotide and 96% amino acid similarity (segment 2), and 98% nucleotide and 98% amino acid similarity (segment 6).

African Horse Sickness Virus↗
PubMed1994

Detection of African horsesickness virus by reverse transcriptase polymerase chain reaction (RT-PCR) using primers for segment 5 (NS1 gene).

The reverse transcription followed by the polymerase chain reaction (RT-PCR) technique was applied to the detection of African horsesickness virus (AHSV) using primers specific for attenuated AHSV serotype 4 segment 5 (NS1 gene). Total RNA which contains both messenger RNA and genomic dsRNA was extracted by the acid guanidinium-phenol-chloroform method from the AHSV infected Vero cells and was used as templates to optimize the RT-PCR. A pair of primer (NP2-NP32) amplified the product of the expected size from all serotypes of attenuated AHSV when four pairs of primers were tested. Using this primer pair, no RT-PCR product was detected from the RNA samples extracted from ten other orbiviruses infected cells and their virions. In addition, RT-PCR using a serial dilution of RNA samples suggested that AHSV was efficiently detected from 1 to 2 cells of the cell monolayer infected with 10(6) TCID50 of AHSV. The RT-PCR concerning with total RNAs of AHSV NS1 gene was found to be a specific and sensitive method for the detection of AHSV.

African Horse Sickness↗
PubMed1994

Pressor and subpressor doses of angiotensin II increase insulin sensitivity in NIDDM. Dissociation of metabolic and blood pressure effects.

There is evidence that the renin-angiotensin system may be involved in the metabolic as well as the cardiovascular features of diabetes and that pressor doses of angiotensin II (ANG II) increase insulin sensitivity in parallel with blood pressure (BP) in healthy subjects, but the effects of ANG II on insulin sensitivity have not been previously reported in patients with non-insulin-dependent diabetes mellitus (NIDDM). In a randomized, double-blind, placebo-controlled, crossover study, 11 patients with NIDDM attended 3 study days to evaluate the effects of a 3-h infusion of subpressor and pressor doses of ANG II on whole body insulin sensitivity using the euglycemic hyperinsulinemic clamp. BP and heart rate were recorded, and blood samples were collected for serum insulin, C-peptide, potassium, catecholamines, plasma renin activity, and plasma ANG II concentrations. Plasma levels of ANG II (means +/- SD) were 9 +/- 4, 29 +/- 9, and 168 +/- 47 pmol/ml after placebo, low dose infusion, and high dose infusion, respectively. The higher dose of ANG II was associated with significant increases in BP (e.g., 18 mmHg systolic BP at 150 min) and plasma aldosterone. Whole body insulin sensitivity was 23.8 +/- 12.7 mumol glucose.kg-1.min-1 after placebo and 30.6 +/- 12.7 and 27.2 +/- 13.3 following low and high dose ANG II infusions, respectively (P < 0.05, analysis of variance). In summary, acute infusion of ANG II, with or without an increase in BP, increases insulin sensitivity in normotensive patients with NIDDM.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Development of a novel drug release system, time-controlled explosion system (TES). I. Concept and design.

A novel controlled drug release system. Time-Controlled Explosion System (TES) has been developed. TES has a four-layered spherical structure, which consists of core, drug, swelling agent and water insoluble polymer membrane. TES is characterized by a rapid drug release with a precisely programmed lag time; i.e. expansion of the swelling agent by water penetrating through the outer membrane, destruction of the membrane by stress due to swelling force and subsequent rapid drug release. For establishing the concept and development strategy, TES was designed using metoprolol and polystyrene balls (size: 3.2 mm in diameter) as a model drug and core particles. Among the polymers screened, low-substituted hydroxypropylcellulose (L-HPC) and ethylcellulose (EC) were selected for a swelling agent and an outer water insoluble membrane, respectively. The release profiles of metoprolol from the system were not affected by the pH of the dissolution media. Lag time was controlled by the thickness of the outer EC membrane; thus, a combination of TES particles possessing different lag times could offer any desired release profile of the model compound, metoprolol.

Chemistry, Pharmaceutical↗
PubMed1994

Development of a novel drug delivery system, time-controlled explosion system (TES). IV. In vivo drug release behavior.

Time-Controlled Explosion System (TES) has the time-controlled drug release property with a pre-designed lag time. The drug release from the system is initiated by destruction of the membrane. In this study, metoprolol tartrate was used as a model drug. After five types of TES with different in vitro lag times were orally administrated to dogs, plasma metoprolol concentration was monitored. There existed a good correlation between in vitro and in vivo lag time, while the extent of absorbed metoprolol decreased with prolongation of lag time. Next, the in vivo drug release behavior was directly investigated using five different colored TES with a lag time of two hours. Each TES was consecutively administrated to the fasted dogs at predetermined intervals. The amount of metoprolol released was monitored by recovering the administered TES from the gastrointestinal trace. The in vivo release profile corresponded with the in vitro one. It is demonstrated that TES can release the drug in in vivo conditions similarly to in vitro. Based on these results, the decrease of the absorption is suggested to be caused by increased hepatic first-pass metabolism of the drug due to the retarded release rate with longer lag time.

Animals↗
PubMed1994

Pharmacokinetics and pharmacodynamics of the alpha 1-adrenergic antagonist bunazosin retard in hypertensives.

The pharmacokinetics and pharmacodynamics of an alpha 1-blocker a sustained release formulation of bunazosin (Detantol R, E1015, 4-amino-2-(4-butyrylhexahydro-1H-1,4-diazepin-1-yl)-6,7- dimethoxyquinazoline hydrochloride, CAS 52712-76-2), were investigated in hypertensive patients with normal renal function (NRF) and those with impaired renal function (IRF). The subjects were hospitalized and placed on a constant sodium diet (NaCl 7 g/day) throughout the study. A 6 mg dose of bunazosin was administered orally once a day for 8 days. Measurement of blood pressure (BP) and sampling of blood and urine specimens were made on the first and last days of treatment. A significant decrease in both systolic and diastolic BP was observed after consecutive dosing of bunazosin compared to baseline values over 24 h in the NRF and for 8 h in the IRF. There were no significant differences in plasma profiles of bunazosin in both groups after single and consecutive dosing. The pharmakokinetic parameters of bunazosin in the NRF and IRF groups did not differ after the single and the consecutive dosing, except for plasma peak levels (Cmax) which were significantly higher in the IRF than those in the NRF. There were, however, neither prolongation of apparent elimination half-life (t1/2), nor increase in Cmax, nor area under the plasma concentration-time curve (AUC0-24) after consecutive dosing in both groups. Cumulative urinary excretion rates of bunazosin were less than 1.1% of dose in both groups, and those did not differ significantly between the NRF and IRF groups in both single and consecutive studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1994

[Carbon-11 labeled diacylglycerol for signal transduction imaging: effect of the solubilizer on the distribution and radiation dosimetry].

Carbon-11 labeled diacylglycerol (11C-DAG) has been developed as a signal transduction imaging agent for the CNS, and it can visualize the second messenger. For clinical application by positron CT (PET), the 11C-DAG solution must be prepared for intravenous injection. However, the 11C-DAG does not dissolve in water because of its lipophilicity and requires a solubilizer such as human serum albumin (HSA) and Tween 80 (TW-80). We examined the influence of these solubilizers on the tissue distribution of 11C-DAG, and estimated the radiation dosimetry. In the brain, uptake of 11C-DAG dissolved with HSA was 1.3-1.8 times higher than that of dissolved with TW-80. On the other hand, the lung and spleen showed a higher uptake of 11C-DAG using TW-80 than when using HSA. Especially, the lungs showed 20-40 times higher uptake than when using HSA. Also, the washout of radioactivity from tissue was slower, and the dose of radiation exposure was estimated to be higher, with TW-80 than with HSA. Therefore, between TW-80 and HSA with different solubilizing mechanisms, the later was suggested to be a better solubilizer of 11C-DAG.

Animals↗