Biomedical subjects

Y Hosoda

Publications and source records attributed to Y Hosoda.

At least 73 records · Page 4Linked to original sources

PubMed1998

Characteristics of spontaneous erythema appeared in hairless rats.

The hairless rat (WBN/Kob-Ht), a dominant mutant rat derived from the Wistar strain, rarely develops spontaneous erythema of a progressive nature on its skin. Erythema was first observed at 8 weeks of age and the incidence at 20 weeks of age was about 4% in both males and females. Histopathologically, erythema was characterised by dermatitis induced by an immunological reaction. Areas of erythema in the skin were decreased by treatment with dexamethasone (1 mg/kg) or ciclosporin (25 or 50 mg/kg). These results suggested that erythema on the hairless rat could be used as an animal model of spontaneous dermatitis.

Animals↗

PubMed1998

[A case of synchronous resection of double cancers in the lung and stomach through median sternotomy and abdominal incision].

A 72-year-old male was admitted to our clinic for the treatment of early stomach cancer. A chest X-ray film on admission showed a mass in the right lung field. CT scan and transbronchoscopic lung biopsy revealed lung cancer (C-T2N2M0-stage IIIA). Histologically it was poorly differentiated adenocarcinoma, which was different from stomach cancer. We underwent synchronous resection of this double cancer through median sternotomy and abdominal incision. We conducted lobectomy, bilateral mediastinal lymph node dissection, and wedge resection of stomach. Postoperative diagnosis was early lung cancer (p-T2N0M0-stage I) and advanced stomach cancer (A-IIc+IIa advanced t2 (mp) n1H0P0M0-stage II). Postoperative course was stable and the patient was healthy at present. As such, this case report suggests that synchronous double cancers involving the lung and stomach, if both cancer are early stage, should be resected synchronously.

Abdomen↗

PubMed1998

[Coronary reoperation].

From 1884 to 1997, 24 patients (1.3%) underwent coronary reoperation in a mean of 10.18 +/- 3.35 ears after the first operation at Juntendo University. The mean age of the patients at reoperation was 60.7 +/- 8.0 years. Although 2 patients had received a left internal thoracic artery graft at the primary operation, both grafts were already occluded. At reoperation, 19 patients received at least one internal thoracic artery, and 2 received a gastroepiploic artery graft. The mean number of grafts was 1.96 +/- 0.67 at reoperation. One patient underwent reoperation combined with pseudoaneurysmectomy at the proximal anastomosis site, and one patient reoperation combined with mitral valve replacement. There were 2 in-hospital deaths. The use of an arterial graft to the LAD is recommended at reoperation because of its long-term superiority. Since transmyocardial laser revascularization (TMLR) and minimally invasive direct coronary artery bypass (MIDCAB) at reoperation have recently been reported, these strategies may be considered as useful methods in future.

Adult↗

PubMed1998

Mitral valve aneurysm as a sequela of infective endocarditis: review of pathologic findings in Japanese cases.

Mitral valve aneurysm is defined as a localized protrusion of the valve with a different radius from that of the remaining portion of the valve. The medical records and pathological findings of seven patients with mitral valve aneurysm [aged 48-69 years (mean 64), 4 males] and the pathological findings of other 29 Japanese cases were reviewed. All seven patients were diagnosed pathologically as infective endocarditis, but two patients had no documentation of clinical symptoms suggestive of infective endocarditis (latent infective endocarditis). The underlying lesion of the heart was aortic valve disease and/or fibrosal degeneration of the mitral valve. Only 29 of 36 Japanese case reports stated a precise description of the valve pathology. Of these 29 cases, 23 were associated with infective endocarditis, two with rheumatic valvular disease with fusion and/or shrinkage of the chordae tendineae, three with mitral valve prolapse or myxomatous degeneration of the mitral valve, and one with aortitis syndrome. Neovascularization was described in eight cases. Neovascularization with thick wall should be considered as post-inflammatory vascularization. This review indicates that patients with latent infective endocarditis and mitral valve aneurysm should be considered as potential candidates for valve surgery.

Aged↗

PubMed1998

Right vagal nerve stimulation during minimally invasive direct coronary artery bypass grafting in dogs. A preliminary study.

BACKGROUND: Minimal access coronary artery bypass grafting without cardiopulmonary bypass has been used with increasing frequency. However, some surgeons are still unwilling to perform MIDCAB because the anastomosis is technically demanding. The aim of this study was to assess whether autonomic activation via right vagal nerve stimulation will be an effective support technique on heart rate during MIDCAB in dogs. EXPERIMENTAL DESIGN: Preliminary study. SETTING: Cardiothoracic Surgery Unit, University Clinic. METHODS: The right cervical vagal nerve was stimulated in five dogs. In one dog, right thoracotomy was performed to isolate the vagal nerve. Bipolar hook electrodes were attached to the vagal nerve. The vagal nerve was stimulated (3-5 mA, 40 Hz) for a few seconds while suturing the coronary artery. Experiments were conducted in two groups. In Group I, two dogs received vagal stimulation via the right neck, and one dog received vagal stimulation via the right thoracic cavity approach. In Group H, all vagal stimulations were performed via the neck during intravenous infusion of diltiazem (10 mg/hrs) or verapamil (5 mg/hrs). RESULTS: In Group I, when the cervical nerve stimulation started the heart rate decreased from 190 to 45 beats/min in one dog, and from 180 to 42 beats/min in another dog. During thoracic nerve stimulation, the heart rate decreased from 205 to 70 beats/min. In Group II, vagal stimulation of one dog (10 mg/hr diltiazem) caused ventricular arrest, and in the other dogs (5 mg/hr verapamil) vagal stimulation caused marked bradycardia with atrioventricular block. After the cessation of nerve stimulation, the heart rate returned to normal sinus rhythm immediately in each dog. CONCLUSIONS: Based on our findings, this type of autonomic stimulation (especially with i.v. administration of diltiazem or verapamil) can be an effective technique in reducing heart beats, thus obtaining relatively quiet surgical field for coronary anastomosis in CABG without cardiopulmonary bypass.

Animals↗

PubMed1998

[Elevated levels of plasma homocysteine related to saphenous vein graft disease after coronary artery bypass graft surgery].

Elevated levels of plasma homocysteine may be an independent risk factor for coronary atherosclerosis. This study investigated whether plasma homocysteine levels are related to atherosclerotic lesions of saphenous vein grafts after coronary artery bypass surgery. Homocysteine levels were measured in fasting plasma by high-performance liquid chromatography and total cholesterol, triglyceride, high density lipoprotein cholesterol and lipoprotein (a) were also evaluated in 40 patients (mean age 65 +/- 8 years, mean interval after bypass surgery: 6.1 +/- 3.1 years, range 1-13 years). The vein graft disease group was defined as patients with angiographical stenosis of > or = 50% in any vein graft (n = 23). The other patients were defined as the no-vein graft disease group (n = 17). Patients who had a history of chronic renal failure or anatomic lesions of saphenous vein grafts were excluded. The distributions of homocysteine were skewed. Median homocysteine levels were 11.9 nmol/ml in all subjects. Homocysteine levels in the vein graft disease group were significantly higher than in the no-vein graft disease group (median 15.1 vs 10.6 nmol/ml, p = 0.01). In the analysis of plasma lipids, high-density lipoprotein cholesterol levels were significantly lower in the vein graft disease group than in the no-vein graft disease group (mean 37 +/- 11 vs 48 +/- 13 mg/dl, p = 0.01). Multiple regression analysis showed that elevated levels of homocysteine were an independent risk factor for saphenous vein graft disease after coronary artery bypass surgery. These findings indicate that elevated levels of plasma homocysteine are related to atherosclerotic lesions of saphenous vein grafts after coronary artery bypass surgery as well as coronary atherosclerosis.

Aged↗

PubMed1997

Dissemination in Japanese hospitals of strains of Staphylococcus aureus heterogeneously resistant to vancomycin.

BACKGROUND: Since the discovery of the vancomycin-resistant Staphylococcus aureus (VRSA) strain Mu50 (minimum inhibitory concentration [MIC] 8 mg/L), there has been concern about the potential spread of such strains throughout Japanese hospitals. Two important questions need to be answered: (1) what is the prevalence of VRSA, and (2) by what mechanism does vancomycin resistance occur. METHODS: The vancomycin susceptibilities of three methicillin-resistant S aureus (MRSA) strains (Mu50, Mu3, and H1) and the methicillin-susceptible S aureus type strain FDA209P were compared by MIC determinations and population analysis. Mu3 (MIC 3 mg/L) was isolated from the sputum of a patient with pneumonia after surgery who had failed vancomycin therapy. H1 (MIC 2 mg/L), which is a representative vancomycin-susceptible MRSA strain, was isolated from a patient with pneumonia who responded favourably to vancomycin therapy. Subclones of Mu3 with increased resistance against vancomycin were selected with serial concentrations of vancomycin and their MICs were determined. The prevalence of VRSA and Mu3-like strains in Japanese hospitals was estimated by population analysis from 1149 clinical MRSA isolates obtained from 203 hospitals throughout Japan. The genetic traits of the Mu3 and Mu50 strains were compared with clonotypes of MRSA from around the world. FINDINGS: Mu3 and Mu50 had an identical pulsed-field gel electrophoresis banding pattern. When grown in a drug-free medium, Mu3 produced subpopulation of cells with varying degrees of vancomycin resistance, thus demonstrating natural heterogeneity, or variability, in susceptibility to vancomycin. In the presence of vancomycin, Mu3 produced subclones with resistance roughly proportional to the concentrations of vancomycin used. Selection of Mu3 with 8 mg/L or more of vancomycin gave rise to subclones with vancomycin resistance equal to that of Mu50 (MIC 8 mg/L) at a frequency of 1/1,000,000. During screening of Japanese MRSA strains, no strain of VRSA additional to Mu50 was found. The prevalence of MRSA isolates heterogeneously resistant to vancomycin was 20% in Juntendo University Hospital, 9.3% in the other seven university hospitals, and 1.3% in non-university hospitals or clinics. INTERPRETATION: Heterogeneously resistant VRSA is a preliminary stage that allows development into VRSA upon exposure to vancomycin. Heterogeneously resistant VRSA was found in hospitals throughout Japan. This finding could explain, at least partly, the frequent therapeutic failure of MRSA infection with vancomycin in Japan.

Aged↗

PubMed1997

Immunohistochemical and ultrastructural investigation of the human vestibular dark cell area: roles of subepithelial capillaries and T lymphocyte-melanophage interaction in an immune surveillance system.

BACKGROUND: The aim of the present study was to morphologically characterize the structure of the subepithelial blood vessels in the dark cell area of the human vestibular organs, and to determine whether immunocompetent cells such as macrophages and lymphocytes could be found around these small blood vessels. MATERIALS AND METHODS: All 31 surgical specimens (semicircular canals and utricles) were obtained from patients with vestibular schwannoma. Formalin fixed specimens were stained with hematoxylin and eosin (H&E), and with antibodies to von Willebrand Factor (vWF), leukocyte common antigen (LCA), and UCHL-1, and were examined with light microscope. Specimens fixed with glutaraldehyde were examined with a transmission electron microscope (TEM). OBJECTIVES: Subepithelial blood vessels stained positive for vWF. By TEM observation, these blood vessels were observed to be capillaries that consisted of non-fenestrated endothelium, occasional pericytes, and a basement membrane. They were usually accompanied by melanophages with a number of secondary lysosomes containing phagocytosed degraded melanosomes and lipid droplets. Moreover, melanocytes and their cell processes directly surrounded these subepithelial capillaries. The fact that cells which were positively stained with LCA and UCHL-1 were present both in the intra- and subepithelial layer of the specimens, and that by TEM the intra- and subepithelial mononuclear cells with a lymphoid appearance had clustered dense bodies in their cytoplasm, suggested that they were a population of T lymphocytes. CONCLUSIONS: Results suggested the possibility of a T lymphocyte-melanophage (macrophage) interaction, both originating from and harbored around subepithelial capillaries, which suggests the presence of an immune surveillance system in the human vestibular organs.

Adult↗

PubMed1997

Assay of gamma-glutamyl transpeptidase activity in amniotic fluid offers a possible prenatal diagnosis of biliary atresia in the rat model.

Muller et al. analysed gamma-glutamyl transpeptidase (GGTP) activity in the amniotic fluid of more than 2000 pregnant women for a prenatal diagnosis. They reported that at 18-19 weeks' gestation, two fetuses associated with lower amniotic fluid GGTP levels were diagnosed after birth as having biliary atresia (BA). If low GGTP values correlate closely with BA, chemical assay of amniotic fluid GGTP could possibly be used in the prenatal diagnosis of BA. A fetal model of cholestasis in the rat was created by the administration of the toxic cytopharmacological agent phalloidin on day 15 of gestation, after which amniotic fluid was aspirated and analysed for GGTP. Fetal liver specimens were examined histopathologically. In the normal rats, amniotic fluid GGTP values rose rapidly after 18 days 8 h, reaching a maximum value at 19 days of gestation. Significantly lower GGTP values were observed in the cholestasis models between 18 days 16 h and 19 days 16 h of gestation (P < 0.05). Our data corroborate Muller et al.'s suggestion that fetuses with cholestasis might demonstrate lower GGTP values in their amniotic fluid at a given stage of gestation. Prenatal diagnosis of BA using the amniotic fluid GGTP assay therefore has considerable potential.

Amniotic Fluid↗

PubMed1997

Ascending aorta to supraceliac abdominal aorta bypass for coarctation of the aorta in an adult.

We present herein a case of ascending aorta to supraceliac abdominal aorta bypass for coarctation of the aorta in a 46-year-old woman with a history of hypertension. Because of severe calcification of the coarctation segment, we performed an ascending aorta to supraceliac abdominal aorta bypass instead of a conventional resection and anastomosis of the coarctation segment. Following surgery, the patient's blood pressure normalized, and she was discharged on the 14th postoperative day without any complications. An ascending aorta to supraceliac abdominal aorta bypass for coarctation of the aorta in adults is thus considered to be safe and easy to perform.

Aorta↗

PubMed1997

Endoscopic monitoring of operative procedures during cardiac surgery.

Both intracardiac repair and fine anastomotic procedures are hard to visualize in the sterile operative field. To overcome this problem, we have recently developed an endoscope video system for intraoperative monitoring in open heart surgery. The endoscope can be introduced into the cardiac cavity in a sterile fashion and thus be used to visualize intracardiac lesions as well as the operative procedures. This endoscopic video monitoring system is considered to be useful not only for thoracic surgery but also for cardiac surgery as well.

Adolescent↗

PubMed1997

Primary leiomyosarcoma of the thyroid gland.

Primary leiomyosarcoma of the thyroid gland is extremely rare, and to the best of our knowledge only five well-documented cases have been reported in the world literature. We herein report a 58-year-old female patient with primary leiomyosarcoma of the thyroid who was successfully treated by total thyroidectomy with a modified neck dissection. Immunohistochemically, the tumor cells showed positive reactivity to alpha-smooth muscle actin and vimentin. Radical surgery was thus considered to be essential in the treatment of this rare but rather aggressive malignancy.

Actins↗

PubMed1997

A hybrid carcinoma: adenoid cystic carcinoma and salivary duct carcinoma of the salivary gland. An immunohistochemical study.

Hybrid tumours of the salivary glands are very rare entities composed of two different tumours, each of which conforms with an exactly defined category. We describe an unusual hybrid carcinoma of the palate; it was comprised of an adenoid cystic carcinoma and a salivary duct carcinoma with a transitional region. These two different compartments showed different characteristics as regards cellular differentiation, proliferative activity, and expression of oncogene and tumour suppressor oncogene proteins, as revealed by using markers for muscle actin, keratin, vimentin, S-100 protein, GFAP, Ki-67, p53, and c-erbB-2 proteins. This case is the first reported with overexpression of p53 and c-erbB-2 proteins in the tumour entities. Salivary gland tumours consist of heterogeneous histological groups, and each has morphological diversity. This case indicates that some of the oncogene and tumour suppressor oncogene proteins may help to produce the histological heterogeneity of the salivary gland tumour.

Actins↗

PubMed1997

Complications after cyst excision with hepaticoenterostomy for choledochal cysts and their surgical management in children versus adults.

The aim of this study was to review the cases 200 children and 40 adults who had cyst excision combined with hepaticoenterostomy (CEHE) for choledochal cyst, with particular emphasis on post-CEHE complications and their surgical management. Patients who had CEHE at the age of 15 years or less were defined as children, and those aged 16 years or older were defined as adults. The mean age when patients became initially symptomatic was 3 years in children and 26 years in adults. Eleven adults became symptomatic as children (< or = 15 years of age). The mean age of CEHE in children and adults was 4.2 years and 35 years, respectively. The time interval between the onset of initial symptoms and CEHE was significantly less in children than in adults (P < .0001). Of the 200 children, 176 had primary CEHE, and 24 had secondary CEHE converted from cystoenterostomy or other biliary surgery. Seventy children had intraoperative cyst endoscopy, which enabled us to examine the proximal intrahepatic bile ducts for stenosis and debris, and to wash out debris, protein plugs, and stones from the intrapancreatic ducts. Of the 40 adults, 22 had primary CEHE, 18 had secondary CEHE. The mean follow-up period was 10.9 years in children and 10.7 years in adults. The number of patients with post-CEHE complications in children and adults was 18 (9.0%) and 17 (42.5%), respectively. The post-CEHE complication rate in children was significantly lower than in adults (P < .0001). The 18 children had 25 post-CEHE complications such as cholangitis, intrahepatic bile duct stones, pancreatitis, stone formation in the intrapancreatic terminal choledochus or pancreatic duct, and bowel obstruction. Twenty-seven post-CEHE complications developed in the 17 adults including 2 cases of cholangiocarcinoma. There were no post-CEHE complications in the 70 children who had intraoperative cyst endoscopy. No stone formation was seen in the 145 children who had CEHE at the age of 5 years or less. Eight stone formations were seen in seven (12.7%) of the remaining 55 children aged over 5 years. Stones developed in seven (17.5%) adults. The incidence of post-CEHE stone formation in children aged 5 years or less was significantly lower than in other children and adults (P < .0001). Reoperation was required in 15 children: revision of hepaticoenterostomy in 4, percutaneous transhepatic cholangioscopic lithotomy (PTCSL) in 1, excision of intrapancreatic terminal choledochus in 2, endoscopic sphincterotomy of the papilla of Vater in 1, pancreaticojejunostomy in 1, and laparotomy for bowel obstruction in 6. Ten adults required reoperations: revision of hepaticoenterostomy in 2, PTCSL in 2, left hepatic lobectomy in 1, endoscopic sphincterotomy in 2, exploratory laparotomy in 2, and adhesiolysis in 1. The authors conclude that early diagnosis followed by CEHE is the treatment of choice for choledochal cyst, and intraoperative cyst endoscopy is recommended as a valuable adjunct to CEHE.

Adolescent↗

PubMed1997

Temporal alterations of endothelial-vasodilator functions in lung injury induced by monocrotaline.

To assess the time course of alterations in pulmonary endothelial vasodilator functions during pathological development of pulmonary hypertension (PH) and right ventricular hypertrophy (RVH), we examined changes in serotonin (5-HT) removal rates and the production of prostacyclin (PGI2) and nitric oxide (NO) in isolated rat lungs harvested at various times after single exposure to monocrotaline (MCT). We assessed the generation of vasodilator substances under conditions of both the absence and the presence of 5-HT in lungs perfused with blood-free solution. Major findings included: (i) remodeling of the pulmonary vasculature associated with RVH evident 14 days after MCT injection; (ii) the capacity for 5-HT removal was suppressed at day 1 and 7 but had been restored by day 14 after MCT exposure; (iii) basal PGI2 production in the absence of 5-HT was augmented at day 1 but had returned to control levels in lungs harvested 7 or 14 days postinjection of MCT; (iv) PGI2 production evoked by 5-HT was suppressed in MCT lungs obtained at all time points examined; (v) basal NO production was suppressed at day 1 but enhanced at day 7 and 14 in MCT lungs; (vi) NO production elicited by 5-HT stimulation in 1-day-MCT lungs was obviously suppressed while that in 7- and 14-day-MCT lungs had been restored to the control level. These findings suggest that transitional changes in endothelial functions including 5-HT removal and production of vasodilators in MCT lungs do not follow the same time course.

Animals↗

PubMed1997

Global epidemiology of sarcoidosis. What story do prevalence and incidence tell us?

Textbooks of clinical medicine often begin with "epidemiology" of the disease by describing the distribution of patients' characteristics in terms of age, gender, race, and so on. As a result, many clinicians erroneously think the description of such distribution is a role only for epidemiology. The real role of epidemiology, however, is to search for the determinants of and ways to prevent the disease. In this article, the recent informative papers on the epidemiology of sarcoidosis are reviewed in the light of modern sarcoidology.

Adult↗

PubMed1997

Histopathological studies on spontaneous occlusion of the circle of Willis (cerebrovascular moyamoya disease).

Spontaneous occlusion of the circle of Willis (cerebrovascular Moyamoya disease; SOCW) was first described by Japanese surgeons and is thought to have a high incidence in the Japanese population. SOCW is characterized by the angiographical findings of the obstructive vascular lesions around the terminal portions of the internal carotid arteries and the formation of abnormal vascular networks visualized in the arterial phase without any definite underlying conditions. Here, we present a detailed histopathological observation of 31 autopsy cases with SOCW to discuss its etiology which is still a matter of dispute. The obstructive vascular lesion around the terminal portions of the internal carotid arteries which is thought to be the primary site affected in SOCW is due to multilayered eccentric intimal fibrous thickening suggestive of organized mural thrombi. In fact, we found thrombotic lesions frequently in the major cerebral arteries, including those of the circle of Willis, of autopsy cases with SOCW. This fact supports the idea that thrombi play an important role in establishment of the vascular lesions. Extracranial vessels are also shown to be involved and it is conceivable that the systemic etiologic factor, such as the systemic background to form thrombi, exists in patients with SOCW.

Adolescent↗

PubMed1997

Retrograde cerebral perfusion through antero-axillary thoracotomy in the aortic arch surgery.

OBJECTIVE: We have recently found that left antero-axillary thoracotomy provides an ideal view of aortic arch and makes the direct cannulation to superior vena cava possible for retrograde cerebral perfusion during circulatory arrest. METHOD: Twelve patients with distal aortic arch aneurysm or aortic dissection underwent the repair of aortic arch through this approach. Mean duration of retrograde cerebral perfusion was 41 min. RESULTS: Two hospital deaths occurred due to respiratory failure and stroke. The remaining patients survived without any neurological deficits. CONCLUSION: Antero-axillary thoracotomy may be an ideal approach which combines the advantages of median sternotomy and postero-lateral thoracotomy.

Adult↗