Biomedical subjects

M Yoshitake

Publications and source records attributed to M Yoshitake.

At least 37 records · Page 2Linked to original sources

PubMed1998

[Thoracic aneurysm repair using circulatory arrest or retrograde cerebral perfusion].

Ascending aortic and transverse arch aneurysm repair requires some brain protection. At our hospital, profound hypothermia, circulatory arrest and retrograde cerebral perfusion have been used. Thirty patients for whom we used such brain protection techniques were studied with regard to incidence of stroke. Of these 30 patients, 7 underwent circulatory arrest with median arrest time was 31 minutes (range, 25 to 42 minutes), and 23 underwent retrograde cerebral perfusion with median perfusion time was 59 minutes (range, 24 to 123 minutes). The overall 30-day mortality rate was 16.6% (5 of 30 patients); these patients were all aortic dissection cases, and had exhibited signs of vital organs ischemia before the operation. Of the twenty-five patients who survived the operation, incidence of stroke was observed in 2 patients. One was a saccular transverse arch aneurysm, who underwent 71 minutes retrograde cerebral perfusion; debris was the cause of stroke in this case. The other was a Stanford type A aortic dissection, who underwent 32 minutes perfusion; malperfusion caused stroke in this case. Stroke did not occur in any of the 3 patients who underwent retrograde cerebral perfusion for more than 100 minutes. These results suggest that a uniform and constant cooling of the entire brain is important for brain protection. To this end, transapical aortic cannulation is effective to prevent malperfusion. It is also suggested that retrograde cerebral perfusion time can be up to 100 minutes, a longer duration hitherto accepted.

Adult↗

PubMed1997

Vesnarinone inhibits adenosine uptake in endothelial cells, smooth muscle cells and myocytes, and mediates cytoprotection.

Vesnarinone is a novel synthetic inotropic agent. Recently, it has been reported that vesnarinone inhibits adenosine uptake in the B-lymphocytoid cell line. Since extracellular adenosine is cardioprotective, we examined whether vesnarinone inhibits adenosine uptake in cells constituting the cardiovascular system. 1 microCi of -3H-adenosine was added to cells of the myocyte cell line (C2C12), human coronary smooth muscle cell line (HCASMC), human and bovine coronary endothelial cell lines (HCAEC and BCAEC), bovine arterial endothelial cell line (BAEC), and human umbilical venous endothelial cell line (HUVEC). After 10 s-5 min, cells were separated from free [3H]adenosine, and the radioactivity was measured. When 0.1-100 microM of vesnarinone was added to each cell line, the uptake of adenosine was inhibited dose-dependently {% inhibition of -3H-adenosine uptake at 10 and 30 microM of vesnarinone: 14 and 33% (C2C12), 47 and 72% (HCASMC), 37 and 58% (HCAEC), 42 and 68% (BCAEC), 19 and 68% (BAEC), 29 and 59% (HUVEC)}. The cellular viability of HCAEC exposed to 60 min of hypoxia and 60 min of reoxygenation increased from 34+/-5 to 67+/-6% (Trypan blue exclusion test) and 23+/-5 to 78+/-6% (LDH release), which was completely blunted by 8-sulfophenyltheophylline, an adenosine receptor antagonist, and was partially blunted by alpha,beta-methyleneadenosine 5'-diphosphate, an inhibitor of ecto-5'-nucleotidase. We also found that vesnarinone is cytoprotective against hypoxia and reoxygenation in C2C12 and HCASMC. We conclude that vesnarinone inhibits the uptake of adenosine in cardiovascular cells, which contributes to cytoprotection.

Adenosine↗

PubMed1997

[Successful treatment of fulminant myocarditis with the biventricular MEDOS Assist System (MEDOS HIA-VAD)].

BACKGROUND: Successful weaning from biventricular mechanical support with full recovery of the myocardial function is extremely rare in fulminant myocarditis. We report on our experience with the new MEDOS HIA ventricular assist device. METHODS AND RESULTS: We used the MEDOS assist system to support a 30-year-old woman with profound circulatory impairment caused by acute myocarditis. The device provided adequate hemodynamics and recovery of myocardial function. Despite anticoagulation therapy we had to change either the left or right ventricular pump chamber because of clot formation on the surface of the outflow tract. On the 14th postoperative day a surgical reintervention was necessary for bleeding from the cannulation site of the pulmonary artery. After 17 days the myocardial function had recovered and we could remove the assist system. The following parameters were measured before implantation of the MEDOS assist system and after weaning from circulatory support: ejection fraction 15 vs. 45%, cardiac index 0.7 vs. 2.6 L/min/m2, arterial pressure (systolic/diastolic/mean) 81/55/66 vs. 113/66/82 mm Hg, pulmonary artery pressure 33/25/29 vs. 34/20/28 mm Hg, pulmonary capillary wedge pressure 24 vs. 19 mm Hg. CONCLUSIONS: Despite severe cardiac failure in fulminant myocarditis requiring biventricular mechanical support full recovery of the myocardium is possible.

Adult↗

PubMed1997

Configuration of linear dynamic cardiomyoplasty for hypoplastic right ventricle.

BACKGROUND: The purpose of this study is to determine feasibility of linear dynamic cardiomyoplasty with a briefly preconditioned latissimus dorsi in the experimental model simulating patch enlargement of the hypoplastic right ventricle. METHODS: In 8 mongrel dogs, a diminished right ventricular chamber was reconstructed with an extended pericardial patch. A left latissimus dorsi, preconditioned for 2 weeks (2 Hz) after a previous 2-week vascular delay period, was placed on the patch, with the muscle fiber oriented in parallel to the right ventricular long axis. RESULTS: Graft pacing with trained-pulses of 25 Hz at a 1:1 ratio showed significant augmentation of pulmonary flow and pressure (158% +/- 21%, 156% +/- 14%, respectively), contributing to restoring right ventricular function comparable with preoperative control, which was also confirmed by the right ventricular function curve and pressure-volume relationship analyzes. Continuous pacing was performed in 4 animals for 7 hours without evidence of muscle fatigue, implying feasibility of "working conditioning" after minimum preconditioning for this type of right heart assist. CONCLUSIONS: Linear latissimus dorsi myoplasty can restore normal right ventricular performance at a physiologic preload, and may provide a surgical option for the hypoplastic right ventricle.

Animals↗

PubMed1997

MEDOS HIA-VAD biventricular assist device for bridge to recovery in fulminant myocarditis.

Successful weaning from biventricular mechanical support with full recovery of the myocardial function is extremely rare in fulminant myocarditis. We report on our experience with the MEDOS HIA-VAD ventricular assist device. The device worked for 17 days and provided adequate hemodynamics. Despite anticoagulation therapy, we had to change both ventricles because of clot formation on the surface of the outflow tract. After 17 days the myocardial function had recovered and we could remove the assist system.

Acute Disease↗

PubMed1997

Differences in refractory-period response of canine subendocardium and subepicardium to bunazosin, an alpha1-adrenoceptor antagonist, and propranolol during myocardial ischemia.

Our objective was to investigate the effects of alpha1- or beta-adrenoceptor blockers on endocardial and epicardial refractory-period changes during myocardial ischemia in alpha-chloralose-anesthetized dogs. The first and second diagonal branches of the left anterior descending coronary artery were ligated. The refractory period was determined by an S1-S2 extrastimulus method. Dogs were treated with the alpha1-blocker bunazosin (0.1-0.2 mg/kg, i.v.; n = 16), the beta-blocker propranolol (0.2 mg/kg, i.v.; n = 15), or saline (n = 11). Dogs that developed ventricular tachycardia/fibrillation (VT/VF) during the experiment were excluded from the statistical assessment in refractory periods. In all groups, coronary ligation produced a significant shortening of the refractory period of ischemic epicardial tissue (p < 0.05) but only minimal shortening of ischemic endocardial refractory periods, resulting in an increased difference in repolarization time between the endo- and epicardial sites. Treatment with bunazosin ameliorated this ischemia-related shortening of refractory periods at both the endo- and epicardial sites, with a greater effect seen epicardially (p < 0.05), resulting in values similar to those in the nonischemic tissue. Treatment with propranolol prolonged refractory periods more in the epicardial (p < 0.01) than in endocardial sites, exacerbating the disparity in the refractory period between the endo- and epicardial sites (p < 0.05). Propranolol also prolonged the refractory period of nonischemic tissue (p < 0.05 and p < 0.01 in endo- and epicardial sites, respectively), resulting in a significant difference between the ischemic and normal myocardium at the endocardial site (p < 0.05). Results suggest that the alpha1-blocker bunazosin reduces the refractory-period disparity between the ischemic and normal myocardium without increasing the disparity between the endo- and epicardial surfaces, whereas propranolol produces a greater disparity.

Adrenergic alpha-1 Receptor Antagonists↗

PubMed1997

A case of malignant lymphoma with hemophagocytic syndrome presenting as hepatic failure.

We report the case of a 50-year-old female with malignant lymphoma presenting hemophagocytic syndrome and liver failure. She developed high fever, marked jaundice, and progressive liver failure, followed by evidence of disseminated intravascular coagulation (DIC). The course was complicated by severe hepatitis and the patient died six days after admission. Pathological diagnosis on autopsy specimens of the lung hilar lymph nodes was non-Hodgkin's T cell lymphoma, of the diffuse small cell type. Histopathologic examination of the liver demonstrated diffuse liver cell destruction with prominent T lymphocyte infiltration in the portal and periportal area. In addition to marked lymphoma cell infiltration, hemophagocytosis by prominent infiltrative macrophages was observed in various organs, such as the liver and bone marrow, indicating the hemophagocytic syndrome. The hemophagocytic syndrome characterized in the present case may have been responsible for the extremely rapid and fulminant course.

Fatal Outcome↗

PubMed1996

Possible prevention of postangioplasty restenosis by ascorbic acid.

In this preliminary study to assess the possibility of using ascorbic acid to prevent post-percutaneous transluminal coronary angiography (PTCA) restenosis, the incidence of restenosis was significantly less in 50 patients receiving 500 mg/day of oral ascorbic acid than in 51 control patients. Thus, ascorbic acid, a potent natural antioxidant, appeared to be possibly effective in attenuating post-PTCA restenosis.

Adult↗

PubMed1996

Fine et al. Reply.

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Journal Article↗

PubMed1996

Dispase/detergent treated dermal matrix as a dermal substitute.

A method for preparing acellular allogeneic dermal matrix (ADM) and its effectiveness as a dermal substitute are described. Treatment of rat skin with Dispase followed by Triton X-100 completely removed cellular components from the dermis. Subcutaneously implanted ADM evoked no immunological reaction and 20 weeks after implantation, the size of the implanted ADM was reduced to about 60 per cent of its original area. ADM became completely vascularized within 2 weeks after implantation into full thickness skin defects in the rat and inhibited extensive wound contracture. A second layer of ADM placed onto the implanted ADM served as an excellent dressing, providing mechanical protection and permitting vascularization of the underlying implant. Onlay skin autografts placed onto vascularized allogeneic ADM showed good survival when the skin was grafted more than 1 week after ADM implantation. Dispase/detergent treated ADM derived from animal or human skin may be useful in full thickness skin defects providing a vascularized bed for subsequent epidermal coverage.

Animals↗

PubMed1996

Transversely designed dorsal metacarpal V-Y advancement flaps for dorsal hand reconstruction.

Five successful cases of transversely designed dorsal metacarpal V-Y advancement flaps for reconstructing defects on the dorsum of the hand are reported. The flaps were supplied by dorsal metacarpal vessels. Proximally based flaps were used in 2 cases, one of which was supplied by two dorsal metacarpal arteries. Distally based flaps were used in 3 cases. All flaps survived completely.

Adolescent↗

PubMed1996

Bafilomycin A1, a specific inhibitor of vacuolar-type H(+)-ATPases, inhibits the receptor-mediated endocytosis of asialoglycoproteins in isolated rat hepatocytes.

BACKGROUND/METHODS: The role of vacuolar type H(+)-ATPases (v-ATPases) and pH gradient between the endocytic compartments and cytoplasm in the endocytosis of asialoglycoproteins was morphologically investigated in isolated rat hepatocytes using bafilomycin A1, a specific inhibitor of v-ATPases. RESULTS: Fluorescent staining by acridine orange showed that bafilomycin A2 inhibited the acidification of the endocytic compartments. Uptake of gold-conjugated asialofetuin was significantly inhibited by bafilomycin A1. However, bafilomycin A1 did not significantly inhibit uptake of a fluid phase marker, horseradish peroxidase. The number of autophagic vacuoles increased after the bafilomycin A1 treatment. However, materials in the autophagic vacuoles were rapidly degraded after the removal of bafilomycin A1. CONCLUSIONS: Results suggest that: (a) v-ATPases are necessary for acidification of the endocytic compartments; (b) the pH gradient between the endocytic compartments and the cytoplasm which is generated by v-ATPases is necessary for the receptor-mediated endocytosis of asialoglycoproteins, and (c) v-ATPases may contribute to the degradation of the materials in autophagic vacuoles.

Animals↗

PubMed1996

Functional differences between hepatocytes and biliary epithelial cells in handling polymeric immunoglobulin A2 in humans, rats, and guinea pigs.

Immunoglobulin A (IgA) in bile plays an important role in preventing the biliary tract from infection. In the present study, to clarify the functional differences between hepatocytes and biliary epithelial cells (BEC) in handling polymeric IgA2 (pIgA2), the major and important IgA in bile, we have determined in different species the binding characteristics of 125I-labeled pIgA2 to tissue sections of human, rat, and guinea pig livers. We have also examined the binding and transport features of 125I-labeled and gold-labeled pIgA2 in cultured hepatocytes and cultured BEC of rat and guinea pig. Asialofetuin, an asialoglycoprotein, or an antisecretory component antibody was used for determining the binding characteristics of pIgA2 to the cells. Grains of 125I-pIgA2 were morphometrically analyzed. In tissue sections, 125I-pIgA2 was predominantly bound to rat hepatocytes as well as to human and guinea pig BEC. The binding of 125I-pIgA2 to the cells was significantly inhibited by pretreatment with an antisecretory component (SC) antibody (P < .001), but not by preloaded asialofetuin. In cultured cells, labeled pIgA2 was observed binding predominantly to rat hepatocytes and guinea pig BEC as compared with rat BEC and guinea pig hepatocytes (both P < .001), respectively, and gold particles of gold-labeled pIgA2 were localized in the tubulovesicular structures and biliary luminal spaces of those cells. These results suggested that pIgA2 was bound selectively to hepatocytes in the rat liver, and to BEC in the human and guinea pig livers, through the SC but not through an asialoglycoprotein receptor, and was transported transcellularly and secreted into bile.

Animals↗

PubMed1995

Immunological responses after vaccination pre- and post-surgery in dogs.

The effects of several commercially available vaccinations pre- and post-surgery on immune responses by monitoring the blastogenic responses of lymphocytes and humoral antibody responses in dogs were examined. Twenty clinical patients presented for surgery were studied. Canine parvovirus (CPV) serum antibody titers increased by twofold or more in 17 of 20 dogs and many dogs had an increase by day 7. In 3 of 4 dogs moderate hemagglutination inhibition (HI) titers (128 to 256) at the time of vaccination increased by twofold or more. Canine distemper virus serum antibody titers in 4 of 8 dogs with HI titers (< or = 32) at the time of vaccination had increased by twofold or more. In the blastogenic responses of lymphocytes to Concanavalin A and phytohemagglutinin, most dogs responded with a slight decrease following vaccination, but no significant change was noted. No adverse reaction caused by vaccination was noted and comparatively good production of serum antibody titers (CPV especially) was seen. Vaccination pre- and post-surgery neither induce severe immunosuppression, nor potentiate the severity of concurrent disease, and did not cause inapparent infection to become clinically apparent.

Animals↗

PubMed1995

Immunological responses to polyvalent canine vaccines in dogs.

The immunological responses to commercially available polyvalent vaccines in dogs were examined. There was a tendency in decreased lymphocyte counts on day 7 in the puppy and adult dogs. There was a significant increase in the blastogenesis of lymphocytes on day 7 and 21 in puppies, whereas no significant changes were seen in the adult dogs. Delayed type hypersensitivity (DTH) responses to phytohemagglutinin (PHA) and canine parvo-virus (CPV) vaccine monitored 0, 3, 8 weeks after vaccination produced strong reactions, in particular those to CPV vaccine rose significantly after vaccination and maintained the higher responses for at least 2 months. Therefore, it is considered that vaccination is immunomodulative rather than immunosuppressive and that DTH responses to PHA and CPV vaccine are helpful to monitor non-specific and specific immune functions in vivo.

Aging↗

PubMed1995

Role of cytoskeleton and acidification of endocytic compartment in asialoglycoprotein metabolism in isolated rat hepatocyte couplets.

The process of receptor-mediated endocytosis is common to a variety of species and cell types. One of the best characterized receptor-ligand systems is the hepatocyte receptor for asialoglycoproteins. We investigated the morphological features of the uptake and intracellular transport of gold-conjugated asialofetuin in isolated rat hepatocyte couplets. We assessed the effects of colchicine, lumicolchicine, cytochalasin B, and chloroquine on the uptake and intracellular transport of asialoglycoproteins. Isolated rat hepatocyte couplets were incubated with gold-conjugated asialofetuin, and transmission electron micrographs of these cells were analyzed to determine the density and distribution of gold particles in the peripheral and pericanalicular areas. Results were analyzed morphometrically. Colchicine significantly inhibited the uptake and intracellular transport of asialoglycoproteins, but did not affect membrane fusion of endocytic compartments in the peripheral area. Lumicolchicine and cytochalasin B had minimal effects on these processes. Chloroquine inhibited the uptake of asialoglycoproteins, but did not affect the intracellular transport of asialoglycoproteins. Results suggest that the microtubule is essential for intracellular movement of endocytosed asialoglycoproteins and receptor recycling, and that endocytic structures in the peripheral regions can fuse in the absence of intact microtubules. We also found that uptake and intracellular transport of asialoglycoproteins were independent of the microfilaments, and the pH gradient in endocytic compartments was important in receptor-mediated endocytosis of asialoglycoproteins.

Acids↗

PubMed1995

[New configuration of right ventricular dynamic cardiomyoplasty by latissimus dorsi for hypoplastic right ventricle].

UNLABELLED: The purpose of this experimental study is to evaluate the efficacy of linear-type right ventricular (RV) dynamic cardiomyoplasty in a setting of patch enlargement model for hypoplastic RV. In 6 puppies (6-8 kg), under a cardiopulmonary bypass (CPB), RV free wall and septal traveculation were resected and replaced with large pericardial patch, simulating RV patch enlargement of hypoplastic RV. A pedicled left LD, anchored to 3rd rib, wrapped onto the RV patch in parallel to RV long axis, while LD fixed to only RV diaphragma surface without wrapping LV surface. After the termination of CPB, LD flap was synchronously paced at 1:1 ratio with cardiac beat with a trained-pulse stimuli (10-25 Hz). RV performance was tested by RV function curve (RVSWI vs CVP) and RV pressure-volume relationship (ESPVR) assessed by conductance catheter. RESULTS: LD graft stimuration showed significant augmentation of PAP (145 +/- 21%), PA flow (152 +/- 21%) and AP (128 +/- 23%) at CVP of 10 mmHg. RV function curve and ESPVR confirmed dramatical augmentation of RV performance by graft stimulation, which was identical to preoperative normal RV function even at the low CVP range. CONCLUSIONS: Linear LD myoplasty after patch enlargement of RV may viable surgical option for hypoplastic RV.

Animals↗

PubMed1995

[A surgical treatment of transverse arch aneurysm: use of ballooned venous cannula for maintenance of lower half body perfusion].

At present, open distal anastomosis method is widely used for the treatment of aneurysm of the transverse aortic arch during replacement, because anastomosis can be performed under direct vision. However, no established procedure is available for maintaining lower half body perfusion while this procedure is being performed, and various procedures have been employed, e.g. temporary circulatory arrest, low flow perfusion from the femoral artery by use of an occlusion catheter, or retrograde systemic perfusion. Spinal cord injury, MNMS, rhabdomyolysis and other complications cannot be completely prevented even by the use of these procedures. From this point of view, we have been using a ballooned venous cannula to be inserted in to the descending aorta while performing open distal anastomosis in order to prevent these complications. This procedure has the advantage of permitting the surgeon to perform the operation without clamping of the artery, hence without the cessation of the systemic circulation of blood, and we believe that this method will prove effective in the surgical treatment of transverse aortic arch aneurysm.

Aged↗