Biomedical subjects

H Matsuda

Publications and source records attributed to H Matsuda.

At least 955 records · Page 53Linked to original sources

PubMed1994

Coexistence of galanin and substance P in the mouse nasal mucosa, including the vomeronasal organ.

Immunohistochemical fluorescent double labeling revealed the coexistence of galanin and substance P in nerve fibers in the mouse nasal mucosa. At the base of and in the epithelium, all galanin fibers also contained substance P, but around the blood vessels and glands, most of them did not. Since substance P fibers in the nasal mucosa originate from the trigeminal ganglion, these results suggest that galanin fibers in the submucosal region originate from ganglia other than the trigeminal.

Animals↗

PubMed1994

The rejection mechanism of rat pancreaticoduodenal allografts with a class I MHC disparity.

The present study has demonstrated for the first time that PVG.R1 (RT1.AaBcDcCc) pancreatic grafts are rejected by so-called "low"-responder PVG (RT1.AcBcDcCc) recipients with an isolated class I MHC disparity (mean survival time; MST: 21.4 +/- 1.8 days, n = 5), whereas PVG.R1 heart grafts are able to survive indefinitely (MST: > 100 days, n = 5). Splenic CD4+ T cells but not CD8+ T cells from the PVG recipients of PVG.R1 pancreatic grafts show a remarkable proliferative response against donor class I RT1.Aa alloantigens, while only a minimal proliferation is observed in the PVG recipients of PVG.R1 heart grafts or naive PVG rats. Naive PVG rats display an extremely low frequency of IL-2-producing helper T cell precursors (fThp) of 1/40,609 +/- 15,441 against class I RT1.Aa alloantigen. The PVG recipients of PVG.R1 heart grafts have a slightly greater fThp of 1/17,326 +/- 6822. On the other hand, the PVG recipients that rejected PVG.R1 pancreatic grafts show a significantly increased fThp of 1/5030 +/- 3396 compared with those of PVG.R1 heart grafts (P < 0.05) or naive PVG rats (P < 0.01). The frequency of cytotoxic T cell precursors (fTcp) increases slightly in the PVG recipients of PVG.R1 pancreatic grafts (1/1848 +/- 330) compared with those of PVG.R1 heart grafts (1/2215 +/- 2131) or naive PVG rats (1/2476 +/- 585). The size of cytotoxic T cell clones alone does not adequately account for a proliferation sufficient to complete the rejection of pancreatic grafts. The PVG recipients of PVG.R1 pancreatic grafts, but not heart grafts, demonstrate a strong cytotoxic alloantibody response to donor class I RT1.Aa alloantigens. In the study of alloantibodies, IgM is detected mainly in the early phase and IgG in the late phase during the course of pancreatic rejection. It is determined that in blocking studies by FACS analysis these antibodies target class I MHC antigens. These results suggest that cytotoxic T cells do not appear to be responsible for the rejection of PVG.R1 pancreatic grafts in PVG recipients. Rather, the rejection is mediated by CD4+ T cells and complement-fixing antibodies directed at class I MHC antigens.

Animals↗

PubMed1994

Comparison of benzodiazepine receptor and regional cerebral blood flow imaging of epileptiform foci in hippocampal kindled rabbits: a study with in vivo double tracer autoradiography using 125I-iomazenil and 99mTc-HMPAO.

To clarify experimentally whether benzodiazepine (Bz) receptor or regional cerebral blood flow (rCBF) imaging is more sensitive in the detection of epileptic foci, we simultaneously examined the Bz receptor and rCBF distribution changes in hippocampal kindled rabbits with in vivo double tracer autoradiography using 125I-labeled Ro 16-0154 (125I-Iomazenil) and 99mTc-labeled hexamethylpropylene amine oxime (99mTc-HMPAO). In visual and quantitative analyses, 125I-Iomazenil accumulation in brain slices extracted after the completion of the kindling was markedly and extensively decreased in the kindled right CA1 region, and further in the right temporal lobe, dentate gyrus, CA2, CA4, and bilateral CA3 regions, regarded as the propagated sites of seizure discharges. 99mTc-HMPAO accumulation was much more slightly and less extensively decreased in the right CA1, frontal, temporal and dentate gyri. Further, this decrease in 125I-Iomazenil accumulation was not due to neuropathological abnormalities, which consisted only of tissue damage corresponding to electrode track in the CA1. Both the kindled and propagated sites are known to have a possibility of acquiring epileptogenesis as experimental epileptic foci. These results suggest that Bz receptor imaging is much more sensitive in the detection of epileptic foci than rCBF imaging, and therefore that Bz receptor imaging is useful in clinical epilepsy.

Animals↗

PubMed1994

Depressive effects of arenobufagin on the delayed rectifier K+ current of guinea-pig cardiac myocytes.

The effects of a bufadienolide isolated from toad venom, arenobufagin, a potent Na+/K+ pump inhibitor, were studied in single guinea-pig ventricular cells in the whole-cell patch-clamp configuration. Arenobufagin (50 microM) applied extracellularly decreased the amplitude of the delayed rectifier K+ current (IdK) by 30% without affecting the gating kinetics. The L-type Ca2+ current was also depressed, but to a lesser extent. The inward rectifier K+ current was hardly affected. Ouabain and the internal dialysis of cells with the solution containing 20 mM Na+ depressed IdK in a similar way as arenobufagin. On the other hand, arenobufagin also depressed IdK when the Na+/K+ pump was already inhibited in the K(+)-free Tyrode solution. Therefore, both a direct effect on the channel and an indirect effect through the inhibition of the Na+/K+ pump may be involved in the depression of IdK by arenobufagin.

Action Potentials↗

PubMed1994

Metabolism of FK506, a potent immunosuppressive agent, by cytochrome P450 3A enzymes in rat, dog and human liver microsomes.

The oxidative metabolism of FK506 by liver microsomes and purified cytochrome P450 (P450) enzymes from rats, dogs and humans was studied. The major metabolite formed by liver microsomes from all species was 13-demethylated FK506, named M-I. In adult rats, liver microsomal metabolic activity toward FK506 was higher in males than in females and was stimulated by treatment with P450 3A inducers such as dexamethasone and phenobarbital. In a reconstituted monooxygenase system containing various forms of purified P450 3A enzymes, rat P450 3A2, dog P450 DPB-1 (a form of the P450 3A family) and human P450 3A4 catalyzed FK506 oxidation efficiently in the presence of cytochrome b5, a mixture of phospholipids (dilauroylphosphatidylcholine, dioleoylphosphatidylcholine and phosphatidylserine), and sodium cholate. Rat P450 2C6 and 2D1 and human P450 2CMP also metabolized FK506, with significant lower activity than the P450 3A enzymes, and other rat P450 1A, 2A, 2B, 2C and 2E families including C11 did not show catalytic activities for FK506. Anti-P450 3A2 and anti-P450 3A4 antibodies strongly inhibited FK506 oxidation catalyzed by rat and human liver microsomes, respectively. The formation rate of M-I correlated well with testosterone 2 beta- and 6 beta-hydroxylase activities in rat liver microsomes and with immunoquantified P450 3A4 content, nifedipine oxidase activity, and testosterone 6 beta-hydroxylase activity in human liver microsomes. These in vitro findings indicate that the P450 3A enzymes in liver microsomes from various species of animals, including human, play a major role in the first step oxidation of FK506.

Animals↗

PubMed1994

Relation of impaired left ventricular function in mitral regurgitation to left ventricular contractile state after mitral valve replacement.

To reevaluate the postoperative contractile state and survival, 34 patients (19 men and 15 women; average age 45 years, range 23 to 65) undergoing conventional mitral valve replacement between 1980 and 1990 were studied. There were 5 cardiac deaths (2 early and 3 late). Four of 5 deaths occurred in patients who had a preoperative left ventricular end-systolic volume index > 100 ml/m2. Sixteen patients with an end-systolic volume index < 100 ml/m2 (group I), and 5 with an index > 100 ml/m2 (group II) underwent repeat catheterization 8 months (range 4 to 17) after surgery. The ratio of end-systolic wall stress to end-systolic volume index increased significantly after surgery in group I, whereas it remained reduced in group II. The postoperative end-systolic wall stress/volume index ratio correlated significantly with the preoperative end-systolic volume index (p < 0.001). In the relation between end-systolic wall stress and ejection fraction, all patients in group II had values that were less than the 95% confidence limits for the normal relation. In conclusion, patients with a preoperative end-systolic volume index > 100 ml/m2 appeared to be at high risk of incurring irreversible depressed myocardial contractility, with a high postoperative mortality.

Adult↗

PubMed1994

Bcl-2 expression in the thymus and periphery.

Bcl-2 proto-oncogene is expressed in normal lymphoid tissues and its role has been suggested to involve the selection of B and T cells. Here we report three-color flow cytometric studies on the expression of bcl-2 protein in the thymus and periphery. Bcl-2 was expressed in the majority of T and B cells and down-regulated only in the CD1+, CD3- to low, CD4+8+ thymocytes, and the B cells that are in cell cycle in the tonsil and lymph node. In contrast, the CD2+, CD1-3-4-8-19-, early T cells, and mature single positive cells in the thymus, as well as the tonsilar and lymph node T cells, irrespective of their cell cycle status, expressed bcl-2. These results are consistent with the notion that bcl-2 is down-regulated in the T and B cells that are in the process of generating new antigen receptors and subject to subsequent positive selection.

Adult↗

PubMed1994

Changes in biliary glutathione level during ischemia-reperfusion of rat liver.

Changes in hepatic and biliary glutathione levels were studied in rat liver treated with tert-butyl hydroperoxide (t-BuOOH) and subjected to ischemia-reperfusion. Immediately after t-BuOOH administration, the oxidized glutathione (GSSG) values and reduced glutathione (GSSG/GSH) ratio in the bile increased dose-dependently and then returned to control level within 10 min, whereas the hepatic ATP level and bile flow rate were not affected by t-BuOOH at doses of up to 1.0 mmol/kg. These data suggested that the liver remains viable on treatment with up to 1.0 mmole/kg t-BuOOH, and that hepatocytes can rapidly dismute t-BuOOH at up to this dose. The hepatic GSH and GSSG levels did not vary appreciably during ischemia for 10 or 30 min or during subsequent reperfusion, but the GSSG/GSH ratio increased after ischemia for 30 min. The rate of bile flow and the biliary level of GSH decreased after ischemia for 30 min in proportion to the decrease in the hepatic ATP level. However, the biliary GSSG concentration did not vary on reperfusion, although GSSG secretion into the bile is also related to the hepatic ATP level. As a result, the GSSG/GSH ratio in the bile increased during reperfusion after ischemia for 30 min. This increased ratio is thought to reflect oxidation of hepatic GSH by hydroperoxide produced during reperfusion. The GSSG/GSH ratio in the bile after 30 min ischemia corresponded to that observed after a small dose (0.07 mmole/kg body wt) of t-BuOOH, which hepatocytes could dismute rapidly without loss of their viability.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗

PubMed1994

Pathogen invasion and host extinction in lattice structured populations.

We examined the propagation of an infectious disease and the eventual extinction of the host population in a lattice-structured population. Both the host colonization and pathogen transmission processes are assumed to be restricted to act between the nearest neighbor sites. The model is analyzed by an improved version of pair approximation (IPA). Pair approximation is a technique to trace the dynamics of the number of nearest neighbor pairs having particular states, and IPA takes account of the clustering property of lattice models more precisely. The results are checked by computer simulations. The analysis shows: (i) in a one-dimensional lattice population, a pathogen cannot invade a host population no matter how large is the transmission rate; (ii) in a two-dimensional lattice population, pathogens will drive the host to extinction if the transmission rate is larger than a threshold. These results indicate that spatially structured population models may give qualitatively different results from conventional population models, such as Lotka-Volterra ones, without spatial structure.

Biometry↗

PubMed1994

The development of a small bowel volvulus in the early postoperative period following a distal gastrectomy: report of a case.

A 51-year-old Japanese man who underwent a standard distal gastrectomy for cancer of the stomach developed abdominal pain when oral intake was commenced on the 6th postoperative day after an uneventful postoperative course. Complete obstruction of the jejunum led to a sudden deterioration in his general condition and a laparotomy was performed, revealing counterclockwise rotation of the mesenterium. The necrotic portion of the small intestine was removed, while 10 cm of the upper jejunum and 100 cm of the terminal ileum were preserved. His second postoperative course was uneventful apart from the development of "intestinal hurry," which is now under medical control 9 months after his second laparotomy.

Adult↗

PubMed1994

The clinical characteristics of patients with synchronous squamous cell carcinoma of the esophagus and hepatocellular carcinoma.

An ongoing analysis of 762 patients with esophageal cancer revealed 4 (0.52%) male patients with synchronous hepatocellular carcinoma (HCC). A long history of habitual alcohol intake and heavy cigarette smoking was recognized in all four patients and, therefore, the possibility of these two factors being independent risk factors for this double cancer was suggested. Palliative treatment was undertaken since either one or both cancers were too far advanced, or because liver function was poor even in those patients with resectable cancers. The prognosis correlated more closely to the TNM stage of esophageal cancer rather than the HCC and the causes of death were related to the esophageal cancer in all four patients. These findings suggest that, in patients with this combination of double cancer, the state of the esophageal cancer may be a more reliable prognostic factor than that of the HCC and thus, the curability of esophageal cancer is of primary importance.

Aged↗

PubMed1994

Myocardial protective effect of deep hypothermic cardiac arrest without aortic cross clamp in neonatal hearts: comparison with cardioplegic arrest in a rabbit model.

Using an isolated perfusion model of neonatal rabbit hearts aged 3 to 6 days, cardioplegic arrest (CPA) using crystalloid cold cardioplegia with aortic cross clamp (AXC: 60 min, n = 15) and continuous deep hypothermic perfusion (DHP) at 15 degrees C without AXC (n = 15) were compared. The hearts were divided into two subgroups: intact hearts (n = 18) and with preceding 40 min warm ischemia (stressed hearts, n = 22). In the intact hearts, there were no significant differences between the CPA and DHP groups in left ventricular function, myocardial water content, and myocardial mitochondrial score after reperfusion. In the stressed hearts, recovery of cardiac output and left ventricular work was significantly higher in the DHP group than in the CPA group. The post-reperfusion myocardial mitochondrial score was significantly better in the DHP group than in the CPA group. These results suggest that non-AXC DHP may be advantageous in the setting of stressed hearts with preceding ischemic injury where conventional CPA cannot provide adequate myocardial protection.

Animals↗

PubMed1994

Contact invasion by a polypoid pseudosarcomatous carcinoma of the esophageal wall: report of a case.

We present herein the interesting case of a 43-year-old man in whom a rapidly growing polypoid tumor of the esophagus was histologically proven to be pseudosarcomatous carcinoma. Of particular interest was the unusual type of invasion displayed by this tumor, whereby the head of the polyp came into contact with and directly invaded the esophageal wall at the distal end of the pedicle to the submucosal layer, while invasion near the stalk was restricted to the mucosa. This style of invasion is considered to be caused by the mechanical pressure produced by the rapid growth of the tumor in the narrow esophageal lumen.

Adult↗

PubMed1994

Response of right ventricular systolic function to exercise stress: effects of pulmonary vascular resistance on right ventricular systolic function.

To elucidate factors influencing responses of right ventricular systolic function to exercise stress, we evaluated the right ventricular ejection fraction and peak ejection rate with two different loading conditions, atrial septal defect and mitral stenosis, at rest and during exercise by means of gated equilibrium blood pool radionuclide ventriculography. In both atrial septal defect and mitral stenosis, strong correlations between changes in the right ventricular ejection fraction with exercise and pulmonary vascular resistance at rest (r = -0.97, p < 0.001; r = -0.86, p < 0.005: respectively) were found. Significant correlations between changes in the right ventricular peak ejection rate with exercise and pulmonary vascular resistance at rest (r = -0.85, p < 0.05; r = -0.75, p < 0.01: respectively) were found in atrial septal defect and mitral stenosis. Both the right ventricular ejection fraction and peak ejection rate were lower during exercise than at rest when pulmonary vascular resistance at rest was more than 200 dynes.sec.cm-5.m2 in both atrial septal defect and mitral stenosis. In conclusion, right ventricular systolic function responding to exercise stress was influenced by the pulmonary vascular resistance in both atrial septal defect and mitral stenosis.

Adult↗

PubMed1994

Multichannel myocardial temperature probe.

We present a new system to measure myocardial temperature at multiple points in myocardium. This system consists of a probe with multiple thermocouples, a data collector, and a personal computer. We have demonstrated a change in distribution of temperature in myocardium during hypothermic cardioplegic arrest.

Bias↗

PubMed1994

Changes in left ventricular performance after global ischemia: assessing LV pressure-volume relationship.

To determine the effect of ischemia and reperfusion on left ventricular systolic function, we studied the ischemia-induced rightward shift of the ventricular pressure-volume relationship. Eight mongrel dogs were intubated, and their hearts were exposed through a thoracotomy. A conductance catheter and micromanometer were used to obtain instantaneous left ventricular pressure-volume data. The dogs were subjected to 20 minutes of normothermic global myocardial ischemia, followed by 80 minutes of reperfusion under total cardiopulmonary bypass. Data were acquired during transient (10- to 12-second) periods of acute volume loading before ischemia and at 20-minute intervals during reperfusion as bypass was continued. The relationship between stroke work and end-diastolic volume (ie, preload recruitable stroke work [PRSW]) and the end-systolic pressure-volume relationship were highly linear throughout the study (mean r = 0.954 to 0.983 for PRSW; mean r = 0.954 to 0.984 for end-systolic pressure-volume relationship). Ischemia produced changes in the PRSW: (1) the slope decreased significantly at 20 minutes and 40 minutes of reperfusion then returned to preischemic levels at 60 minutes and 80 minutes, and (2) the x-intercept increased significantly up to 60 minutes. The preload recruitable work area (the area under the linear regression line of PRSW) reflected changes in both slope and x-intercept of PRSW and was significantly decreased throughout the 80 minutes of reperfusion despite gradual recovery. The slope and the x-intercept of the end-systolic pressure-volume relationship did not change after ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Study of efficacies of leukocyte-depleted terminal blood cardioplegia in 24-hour preserved hearts.

To evaluate the effect of leukocyte-depleted terminal blood cardioplegia on prolonged preservation, 41 canine hearts were stored in modified Collins' solution and transplanted heterotopically. Hearts were transplanted soon after harvesting in group 1 and after 24-hour preservation in groups 2, 3, and 4. Blood cardioplegia was applied just before aortic unclamping in groups 3 and 4; group 3 received simple blood cardioplegia and group 4 received leukocyte-depleted cardioplegia. The percentage of the preload recruitable stroke work and diastolic compliance after transplantation compared with the preharvesting value in group 4 did not differ from those in group 1, but the percentage of the preload recruitable stroke work in groups 2 and 3 was significantly lower than that in groups 1 and 4. The percentage of diastolic compliance in groups 2 and 3 was significantly higher than that in groups 1 and 4. Coronary blood flow 40 minutes after aortic unclamping in group 4 did not differ from that in group 1, but was significantly higher than the blood flows in groups 2 and 3. Significant production of malondialdehyde was detected during terminal blood cardioplegia and 10 minutes after aortic unclamping in groups 2 and 3, but never in groups 1 and 4. After leukocyte-depleted terminal cardioplegia, the myocardial adenosine triphosphate content increased to the preharvesting value in group 4. Our results suggest that leukocyte-depleted terminal blood cardioplegia may be effective in replenishing the energy-depleted myocardium and reducing reperfusion injury, resulting in adequate cardiac function.

Adenosine Triphosphate↗

PubMed1994

Plication of paralyzed hemidiaphragm after right sleeve pneumonectomy.

Right diaphragmatic plication was performed in a 62-year-old man who underwent right sleeve pneumonectomy and then required prolonged mechanical ventilation owing to right diaphragmatic paralysis. The plication was very effective in allowing him to be weaned from the ventilator. The transdiaphragmatic pressure, the ratio of gastric to esophageal pressure swing, and the work of breathing per liter of ventilation improved remarkably after plication. Our experience indicates the beneficial effect of such a plication on contralateral lung function from the standpoint of clinical and respiratory mechanics.

Carcinoma, Squamous Cell↗