Biomedical subjects

T Mochizuki

Publications and source records attributed to T Mochizuki.

At least 127 records · Page 7Linked to original sources

PubMed1998

Isochronous storage ring of the New SUBARU project.

The aims of the New SUBARU project are to promote industrial applications in the VUV and soft X-ray region and to develop research and development towards new light sources. The main facility of the New SUBARU project is the 1.5 GeV electron storage ring which is under construction at the SPring-8 site in Harima Science Garden City, Japan. The storage ring is quasi-isochronous and has variable momentum dispersion for the deep study of beam dynamics in very short bunches.

Journal Article↗

PubMed1998

Bent-crystal monochromators for high-energy synchrotron radiation.

Two kinds of monochromators covering the energy ranges 100-150 keV and approximately 300 keV have been designed for inelastic (Compton) scattering experiments at the elliptical multipole wiggler beamline, BL08W, of SPring-8. Finite-element analyses using ANSYS for bent crystals indicate that thermal problems are not serious for the 300 keV monochromator, while an energy spread of about 10(-3) for the 100-150 keV monochromator is possible in the centre of the crystal. Detailed calculations of X-ray interaction with the silicon crystal were performed. The results show that Compton scattering is a dominant process and deposits about 100 W continuously.

Journal Article↗

PubMed1998

Nicotine induced up-regulation of nicotinic receptors in CD-1 mice demonstrated with an in vivo radiotracer: gender differences.

Up-regulation of brain nicotinic receptors (nAChRs) by chronic nicotine treatment has chiefly been demonstrated by in vitro binding assays. Here, we report that up-regulation of nAChRs in CD-1 mice can be detected using a specific in vivo radioligand for nAChRs, [125I]IPH. After 10 days of (-)-nicotine administration, male and female mice demonstrated a significant elevation of [125I]IPH binding in all brain regions studied. [125I]IPH uptake also displayed significant gender differences with male animals showing a more pronounced increase in [125I]IPH accumulation.

Animals↗

PubMed1998

[An emergency aortic valve replacement for cardiogenic shock patient with severe aortic stenosis and regurgitation using percutaneous cardiopulmonary support].

The percutaneous cardiopulmonary support system (PCPS) was used in a 64-year-old woman with cardiogenic shock due to sustained ventricular fibrillation (Vf) caused by severe aortic stenosis and regurgitation. The Vf attack was resistant to cardioversion and adrenaline for lack of left ventricular support by PCPS. She was transported to the operation theater with PCPS in situ and emergency aortic valve replacement was performed. Although preoperative cardiac resuscitation time was long (35 minutes), she was discharged from the hospital on foot without any neurological complications on 84th postoperative day. Because PCPS does not decrease left ventricular systolic stress in poorly contracting dilated heart, early surgical treatment is needed in patients with severely damaged heart.

Aortic Valve↗

PubMed1998

[Early hemodynamic effects of olprinone hydrochloride after coronary artery bypass grafting].

Our purpose was to evaluate the hemodynamic effects of olprinone hydrochloride early after coronary artery bypass grafting (CABG). Fifteen patients undergoing CABG were administered a constant infusion of 0.1 microgram/kg/min of olprinone and continued for 4 hours. No bolus infusion of olprinone was administered before continuous infusion. Systolic systemic arterial pressure, systolic pulmonary arterial pressure, systemic vascular resistance and pulmonary vascular resistance were significantly decreased. There were no significant changes in heart rate, mean central venous pressure, mean left atrial pressure and left ventricular stroke work index. Cardiac index was significantly increased, but a correlation between cardiac index and mixed venous blood oxygen saturation was not found. Double product was significantly decreased, which described above suggest that olprinone achieved improvement of left cardiac function without more myocardial oxygen consumption. Severe transient hypotension (systolic arterial pressure < 80 mmHg) after infusion of olprinone was observed in three patients. Olprinone administered soon after CABG surgery had beneficial effects in terms of improvement of hemodynamic status without more oxygen consumption and reduction of pulmonary vascular resistance. However transient hypotension was a serious clinical problem in patients after open heart surgery, especially in CABG patients who need suitable systolic arterial pressure to keep enough blood perfusion of arterial bypass grafts.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1998

[Successful emergency coronary artery bypass grafting after use of a percutaneous cardiopulmonary support system in a patient with cardiopulmonary arrest secondary to acute myocardial infarction].

A 37-year-old woman was taken to a hospital because of sudden chest pain. She lapsed into shock, and the ECG indicated acute myocardial infarction. The ECG later showed ventricular fibrillation, and the patient was given cardiac massage while being transported to our hospital, where she was resuscitated with a percutaneous cardiopulmonary support system. Emergency coronary angiography revealed 99% stenosis of the left main coronary artery. PTCA was performed, and the stenotic lesion was released, but dissection and rapid formation of a thrombus were detected in the LAD. Re-PTCA was performed, but the hemodynamics did not improve, and emergency CABG of the LAD, D1, and LCx was performed. Postoperative max CPK was 18,957 IU/L. Although postoperative MRSA pneumonia developed as a complication, weaning from the respirator was performed 17 days after the operation. The patient was discharged, ambulatory, 74 days after the operation.

Adult↗

PubMed1998

[Preoperative magnetic resonance angiography findings and postoperative neurological complications in 93 cases of CABG with cardiopulmonary bypass].

Between February 1994 and January 1997, 102 of the 146 patients treated by coronary artery bypass grafting (CABG) had undergone magnetic resonance angiography (MRA) of the brain and neck before the operation, and arterial stenosis or occlusion had been detected in 38 (36.9%) of them. Two of these patients had complicating severe calcification of the ascending aorta, and CABG was performed without cardiopulmonary bypass (CPB). Seven patients without stenotic lesions on MRA were also treated by CABG without CPB for other complications. In addition to the 102 patients one patient had been found to have occlusion of the left common carotid artery and poor enhancement of the distal portion, and as a result we switched from CABG to percutaneous transluminal angioplasty (PTCA). We enrolled 93 patients in this study excluding these 10 patients. The patients were distributed into the three groups according to the MRA findings. Group C = no stenotic lesions (58 patients). Group S = stenosis of < 70% (26 patients), Group SS = stenosis of > or = 70% (9 patients). Enhancement distal to the stenotic or occlusive lesions was good in all patients in group S and SS. We then examined them for the incidence of postoperative neurological complications. There were no significant differences among the three groups in regard to age, male/female ratio, or incidence of hypertension and hyperlipidemia. In Group S, the incidence of diabetes was significantly higher than in the other Groups. The incidence of prior stroke was significantly higher and the number of coronary arteries affected was significantly larger in group SS than the other groups. There were no significant differences among the three groups with regard to intraoperative variables. The lowest mean arterial pressure on CPB was 44.3 +/- 7.4 mmHg, 48.0 +/- 8.8 mmHg, 46.3 +/- 7.8 mmHg in Group C, S, and SS, respectively, In all groups the lowest mean arterial pressure on CPB was below 50 mmHg. There were no significant differences among the three groups with regard to time to awaken and time to extubation. Two patients experienced transient conciousness disturbance after CABG, one in Group C, the other in Group SS, but no new lesions were detected by brain CT. Only one patient, in Group C. suffered a stroke and had a new lesion on brain CT a month after the operation. No strokes occurred in the perioperative period. In nine patients with good enhancement distal to the severe stenotic or occlusive lesion on MRA of the brain and neck the lowest mean arterial pressure on CPB was below 50 mmHg, but there was no postoperative neurological complications due to the low perfusion pressure on CPB. The results of this study suggested that CABG with CPB can be performed safely in patients with good enhancement distal to the stenotic or occlusive lesions on MRA of the brain and neck.

Aged↗

PubMed1998

Light and electron microscopic studies of pituitary adenylate cyclase-activating peptide (PACAP)--immunoreactive neurons in the enteric nervous system of rat small and large intestine.

Pituitary adenylate cyclase-activating peptide (PACAP)-immunoreactive (IR) neurons in the myenteric and submucosal plexus of the rat small and large intestine were examined by immunostaining with purified polyclonal antiserum against PACAP (1-15), using both light and electron microscopy. Many PACAP-IR neuronal cell bodies and fibers were found in the myenteric and submucosal plexus. Many of the PACAP-IR fibers originated from the cell bodies of the myenteric and submucosal ganglia. The ganglia were also innervated by PACAP-IR fibers. PACAP-IR fibers penetrated both the circular and longitudinal muscle layers, confirming the previous observations indicating that PACAP neurons act as motor neurons. Ultrastructural study demonstrated that PACAP-IR nerve terminals formed synaptic contacts with PACAP-IR nerve cell bodies or dendritic processes. This observation suggests that PACAP-IR neurons innervate other PACAP-IR neurons, and that PACAP neurons work as interneurons in the enteric nervous system. PACAP-IR nerve cells received not only PACAP-positive nerve terminal input also PACAP-negative nerve terminal input. It also suggests that PACAP neurons are regulated not only by PACAP-IR enteric neurons, but also by neurons originating elsewhere. Our observations support the view that PACAP-IR neurons are involved in the control of gut motility.

Animals↗

PubMed1998

Isolated tricuspid regurgitation caused by a dilated tricuspid annulus.

In most of the previously reported cases of isolated tricuspid regurgitation, both tricuspid leaflets and subvalvar tissue have been absent, hypoplastic, or fused. For this reason, tricuspid valvoplasty was difficult and valve replacement was adopted in many cases. In the present case of a 52-year-old man, however, the tricuspid valve showed no abnormalities other than a severely dilated tricuspid annulus. Ring annuloplasty was performed, and this resulted in a subsequent satisfactory course without anticoagulant therapy.

Dilatation, Pathologic↗

PubMed1998

5-[I-125/123]lodo-3(2(S)-azetidinylmethoxy)pyridine, a radioiodinated analog of A-85380 for in vivo studies of central nicotinic acetylcholine receptors.

The in vivo biodistribution profile of the novel nicotinic acetylcholine receptor (nAChR) radioligand 5-[I-125/123]Iodo-3(2(S)-azetidinylmethoxy)pyridine, [I-125/123]-5-IA, in mouse brain was examined. This radiotracer displayed good brain penetration (3.1% of the injected dose (ID) in whole brain at 15 min post-radioligand injection). Radioligand distribution was consistent with the density of high affinity nAChRs with highest uptake observed in the nAChR-rich thalamus (14.9 %ID/g at 60 min), moderate uptake in cortex (8.5 %ID/g at 60 min), and lowest uptake in the cerebellum (2.4 %ID/g at 60 min). Pretreatment with several different nAChR agonists (A-85380, (-)-nicotine, cytisine) significantly inhibited [I-125]-5-IA binding in all brain regions studied (P < 0.01) demonstrating the high specificity of the radioligand for nAChRs. Blocking doses of the muscarinic antagonist scopolamine and the non-competitive nAChR channel blocker mecamylamine had no significant effect on radioactive uptake supporting the in vitro selectivity of [I-125]-5-IA for the nAChR component of the cholinergic system. [I-125]-5-IA binding sites were shown to be saturable with unlabeled 5-IA. With a relatively low acute toxicity (LD50 > 3 mg/kg via intravenous injection in mice) and high in vivo specificity and selectivity, 5-IA labeled with the imaging radionuclide I-123 may prove useful for single photon emission computed tomography (SPECT) studies of nAChRs in human subjects.

Alkaloids↗

PubMed1998

Three-dimensional ultrasonographic assessments of fetal development.

OBJECTIVE: To visualize fetal surface anatomic structures in advancing gestation by use of three-dimensional ultrasonography with a specially developed abdominal three-dimensional transducer. METHODS: One hundred six normal fetuses from 9 to 40 weeks' gestation were studied with a specially developed abdominal three-dimensional transducer (3.5 MHz). This imaging system can provide conventional two-dimensional ultrasonography images and also can generate within seconds high-quality three-dimensional images in the surface and transparent modes with no need for an external workstation. We determined percentage of surface anatomic structures visualized at each trimester using two-dimensional and three-dimensional ultrasonography. RESULTS: The number and the clarity of surface anatomic structures increased from the first to the third trimester of pregnancy. The image quality was less distinct in the first trimester because of the small fetal size. The ability to view the fetal face, hands, and feet was better with three-dimensional ultrasonography than with two-dimensional ultrasonography in the first trimester (P < .05), whereas fetal genitals were viewed better with two-dimensional ultrasonography than with three-dimensional ultrasonography in the second and third trimesters (P < .05). CONCLUSION: Three-dimensional ultrasonography provides a new means of visualizing surface anatomic structures of the fetus in utero. Our results suggest that three-dimensional ultrasonography has the potential to be a supplement to two-dimensional ultrasonography and should be useful in evaluating fetal abnormalities in high-risk pregnancies.

Embryonic and Fetal Development↗

PubMed1998

Oxyntomodulin reduces hydromineral transport through rat small intestine.

Glicentin (GLIC) and oxyntomodulin (OXM) are released from the ileum and colon during digestion. Both hormones reduce fluid and proton secretion in the stomach. The luminal concentration of sodium and chloride underlying the nutrient absorption, the effect of OXM on electrolyte transport through the small intestine, was assessed in vivo using ligated loops and in vitro using Ussing chambers. In vivo, a zero transport state, estimated by the net water, chloride, and sodium fluxes, was observed when an 80 mM NaCl normoosmolar solution (274 mosm) was administered intraluminally. Active secretion was observed with hyperosmotic challenge (474 mosm). The amplitude of this active secretion increased 2.5- to 3-fold when an electrogenic challenge (NaCl 40 mM) was substituted to the hyperosmotic one. OXM (800 fmol/ml plasma) did not modify the basal transport in the duodenum or in the jejunum (t = 45 min). When active secretion was induced by the hyperosmotic challenge, OXM (200 fmol/ml plasma) had no effect on duodenal or jejunal transport (t = 50 min). When active secretion was induced by an electrogenic challenge, OXM (300 fmol/ml plasma) preferentially reduced the hydromineral transport in jejunum. In vitro, OXM also induced a reduction in the ion transport towards the jejunal lumen (EC50 = 20 pM), the amplitude of which depended upon the integrity of the tetrodotoxin-sensitive neurons. In conclusion, OXM was able to reduce the large secretion induced in rat jejunum in vivo by an electrogenic gradient. In vitro, the antisecretory effect of OXM was partly mediated by the neurons present in the intrajejunal wall.

Animals↗

PubMed1998

Protamine reversal of heparin affects platelet aggregation and activated clotting time after cardiopulmonary bypass.

UNLABELLED: Bleeding after cardiopulmonary bypass (CPB) is related to multiple factors. Excess protamine weakens clot structure and decreases platelet function; therefore, an increased activated clotting time (ACT) after protamine reversal of heparin may be misinterpreted as residual heparin anticoagulation. We evaluated the effects of protamine, recombinant platelet factor 4 (rPF4), and hexadimethrine on ACT in blood obtained after CPB. In addition, we examined the effect of protamine on in vitro platelet aggregation. Incremental doses of protamine, rPF4, and hexadimethrine were added to heparinized blood from CPB, and ACTs were performed. Incremental concentrations of protamine were added to heparinized platelet-rich plasma, and aggregometry was induced by adenosine diphosphate (ADP) and collagen. The mean heparin concentration at the end of CPB was 3.3 U/mL. Protamine to heparin ratios >1.3:1 produced a significant prolongation of the ACT that was not seen with rPF4 and was observed only with 5:1 hexadimethrine to heparin ratios. ADP-induced platelet aggregation was reduced with protamine administration > or =1.3:1. Excessive protamine reversal of heparin prolongs ACT and alters ADP-induced platelet aggregation in a dose-dependent manner in vitro. Additional protamine administered to treat a prolonged ACT may further increase clotting time, reduce platelet aggregation, and potentially contribute to excess bleeding after CPB. IMPLICATIONS: We found that excess protamine prolonged the activated clotting time and altered platelet function after cardiopulmonary bypass, whereas heparin antagonists, such as recombinant platelet factor 4 and hexadimethrine, exhibited a wider therapeutic range without adversely affecting the activated clotting time. Approaches to avoid excess protamine or use of alternative heparin antagonists after cardiopulmonary bypass may be beneficial.

Adenosine Diphosphate↗

PubMed1998

Trimethoprim-sulfamethoxazole for the prevention of methicillin-resistant Staphylococcus aureus pneumonia in severely burned patients.

BACKGROUND: Patients with severe burns are at increased risk of developing methicillin-resistant Staphylococcus aureus (MRSA) ventilator-associated pneumonia. This study was designed to determine whether MRSA pneumonia can be prevented by prophylactic administration of trimethoprim-sulfamethoxazole (TMP-SMX). METHODS: We conducted a prospective, randomized, placebo-controlled study in patients with severe burns (> or = 20%), who required ventilator support. Prophylaxis was done with oral TMP-SMX (80 mg/400 mg) three times daily for 10 days from 4 to 6 days after burn injury. The incidence of MRSA pneumonia and the side effects were evaluated during the administration period. RESULTS: Twenty-one patients were assigned to receive TMP-SMX, and 19 patients to receive placebo. The incidence of MRSA pneumonia was 4.8% in the TMP-SMX group and 36.8% in the placebo group, showing a significant difference (p = 0.017). No major side effects of therapy were seen in the TMP-SMX group. CONCLUSION: Prophylactic treatment with TMP-SMX can prevent MRSA pneumonia in severely burned patients.

Administration, Oral↗

PubMed1998

A simplified method for the quantitative analysis of 99Tc(m)-GSA liver scintigraphy using spectral analysis.

The aim of this study was to develop a simplified method for quantitative analysis of liver scintigraphy with 99Tc(m)-diethylenetriamine pentaacetic acid-galactosyl-human serum albumin (GSA) using spectral analysis. Dynamic liver scintigraphy using GSA was performed in three normal volunteers and 19 patients with chronic liver disease. Dynamic data were obtained with a gamma camera for 30 min after the injection of approximately 185 MBq GSA. The rate constant for the liver uptake of GSA from the blood (Ku, min(-1)), total excretion rate (Ke, min(-1)) and non-specific volume of distribution (Vh) were obtained by spectral analysis. Vh was defined as the volume in the liver region of interest (ROI) occupied by GSA which was in equilibrium with that in the blood. It should be noted that Vh had no units, since the counts in both the liver and heart ROIs were normalized by scan length to obtain counts pixel(-1) min(-). For comparison, compartmental analysis was also performed. A receptor index (LHL15) was calculated by dividing the radioactivity of the liver ROI by that of the liver plus heart ROIs 15 min post-injection. The Ku values obtained by spectral analysis (y) agreed well with those obtained by compartmental analysis (x) (y = 0.953x - 0.013, r = 0.992, S.E.E. = 0.016 min(-1)). The Ke and Vh values obtained by spectral analysis (y) correlated significantly with those obtained by compartmental analysis (x) (y = 1.149x - 0.016, r = 0.826, S.E.E. = 0.017 min(-1) for Ke; y = 1.191x + 0.044, r = 0.975, S.E.E. = 0.021 for Vh). The Ku values obtained by spectral analysis decreased as the severity of liver disease progressed, and were non-linearly related to the LHL15 values, suggesting that Ku is more sensitive to liver damage than LHL15, especially in the early stages of liver damage. These results suggest that spectral analysis applied to dynamic liver scintigraphy with GSA provides a simple, non-invasive and useful tool for the quantitative evaluation of liver function.

Hepatitis↗

PubMed1998

Phylogenetic classification of Trichophyton mentagrophytes complex strains based on DNA sequences of nuclear ribosomal internal transcribed spacer 1 regions.

Using internal transcribed spacer 1 (ITS1) region ribosomal DNA sequences from 37 stock strains and clinical isolates provisionally termed Trichophyton mentagrophytes complex in Japan, we demonstrated the mutual phylogenetic relationships of these strains. Members of this complex were classified into 3 ITS1-homologous groups and 13 ITS1-identical groups by their sequences. ITS1-homologous group I consists of Arthroderma vanbreuseghemii, T. mentagrophytes human isolates, and several strains of T. mentagrophytes animal isolates. Five strains of Arthroderma simii form a cluster comprising ITS1-homologous group II. The Americano-European and African races of Arthroderma benhamiae, T. mentagrophytes var. erinacei, and one strain of a T. mentagrophytes animal isolate constitute ITS1-homologous group III. According to the phylogenetic tree constructed with Trichophyton rubrum as an outgroup, ITS1-homologous groups I and II comprised a monophyletic cluster and ITS1-homologous group III constituted another cluster which was rather distant from the others in the complex. This system was applicable to the phylogenetic analysis of closely related strains. Using this technique, human and animal isolates of T. mentagrophytes were also clearly distinguishable from each other.

Animals↗

PubMed1998

Angiotropic large cell lymphoma which infiltrated to the adrenal glands presenting as reversible adrenal insufficiency.

A 72-year-old man who suffered from recurrent fever was found to have enlarged bilateral adrenal glands on computed tomographic scanning, combined with subclinical adrenal insufficiency. Based on the pathology of bone marrow aspiration, he was diagnosed to have an angiotropic large cell lymphoma (ALCL). Soon after the treatment with a combination chemotherapy, he achieved complete remission of ALCL and size and function of the adrenal glands were apparently normalized. ALCL should be included in the list of differential diagnoses of non-functioning bilateral adrenal swelling with non-specific symptoms such as fever.

Adrenal Gland Neoplasms↗

PubMed1998

A novel insulin sensitizer acts as a coligand for peroxisome proliferator-activated receptor-alpha (PPAR-alpha) and PPAR-gamma: effect of PPAR-alpha activation on abnormal lipid metabolism in liver of Zucker fatty rats.

We investigated the biological activity of a novel thiazolidinedione (TZD) derivative, KRP-297, and the molecular basis of this activity. When administered to obese Zucker fatty rats (obese rats) at 10 mg/kg for 2 weeks, KRP-297, unlike BRL-49,653, restored reduced lipid oxidation, that is, CO2 and ketone body production from [14C]palmitic acid, in the liver by 39% (P < 0.05) and 57% (P < 0.01), respectively. KRP-297 was also significantly more effective than BRL-49,653 in the inhibition of enhanced lipogenesis and triglyceride accumulation in the liver. To understand the molecular basis of the biological effects of KRP-297, we examined the effect on peroxisome proliferator-activated receptor (PPAR) isoforms, which may play key roles in lipid metabolism. Unlike classical TZD derivatives, KRP-297 activated both PPAR-alpha and PPAR-gamma, with median effective concentrations of 1.0 and 0.8 micromol/l, respectively. Moreover, radiolabeled [3H]KRP-297 bound directly to PPAR-alpha and PPAR-gamma with dissociation constants of 228 and 326 nmol/l, respectively. Concomitantly, KRP-297, but not BRL-49,653, increased the mRNA and the activity (1.5-fold [P < 0.01] and 1.8-fold [P < 0.05], respectively) of acyl-CoA oxidase, which has been reported to be regulated by PPAR-alpha, in the liver. By contrast, KRP-297 (P < 0.05) was less potent than BRL-49,653 (P < 0.01) in inducing the PPAR-gamma-regulated aP2 gene mRNA expression in the adipose tissues. These results suggest that PPAR-alpha agonism has a protective effect against abnormal lipid metabolism in liver of obese rats.

Acyl-CoA Oxidase↗