Search PubMed⌕ Search

Biomedical subjects

Y Yokoi

Publications and source records attributed to Y Yokoi.

At least 73 records · Page 4Linked to original sources
PubMed1992

Results of extensive surgery for liver metastases in colorectal carcinoma.

Hepatic resections were performed during the past 13 years on 31 patients with hepatic metastases from colorectal carcinoma. Of the 31 patients, 22 underwent lymph node dissection of the hepatic hilus. Ten patients underwent removal of recurrent lesions in the liver, lung, adrenal gland and brain after initial hepatic resection. The overall 5-year survival rate was 45 per cent. The outcome for six patients who underwent repeat hepatectomy after an initial hepatectomy was significantly better than for nine patients with unresectable recurrence (P less than 0.01). Six of the 22 patients who underwent lymph node dissection had nodes positive for tumour. Two of the six patients underwent repeat hepatectomy and are alive after 49 and 66 months. Three- and 4-year survival rates of patients with positive lymph nodes were both 40 per cent. Repeat hepatectomy and dissection of hilar lymph nodes improves prognosis in selected patients with hepatic metastases of colorectal cancer.

Adult↗
PubMed1992

Portal vein thrombosis after splenectomy successfully treated by an enormous dosage of fibrinolytic agent in a short period: report of two cases.

Portal vein thrombosis (PVT) after splenectomy in a patient with portal hypertension occurs with unusually high frequency. Recently, two patients with PVT following splenectomy were treated by fibrinolytic therapy with an enormous dosage of urokinase (UK) in a short period. PVT was quickly dissolved without side effects and the patients are now doing well without any recurrence of PVT. Therefore, when there is no evidence of bowel infarction, fibrinolytic therapy with an enormous dosage of UK over a short period is deemed to be both effective and essential as a conservative therapy for PVT.

Adult↗
PubMed1992

Aggressive repeat liver resection for hepatic metastases of colorectal carcinoma.

Although hepatectomy for liver metastases from colorectal carcinoma is an effective treatment, recurrence in the liver is still the most common site after hepatectomy. Thirty patients underwent hepatectomy for hepatic metastases and 17 of them had recurrence in the remnant liver during the following 12-year period. Six of the 17 patients underwent a removal of isolated hepatic recurrences. Two of the six patients underwent a third hepatectomy, and three patients underwent partial lung resection on a total of five occasions. There were no operative deaths while complications after a third hepatectomy contributed to a high morbidity rate of 40 per cent. The mean length of survival of the six patients was 28.5 months from the second hepatectomy. The prognosis of the six patients who underwent a repeat hepatectomy was significantly better than that of patients with unresectable recurrence after an initial hepatectomy (p less than 0.01). The overall 5-year survival of 29 patients excluding one in-hospital death was 44.7 per cent. Our results reveal that aggressive removal of isolated and resectable recurrent disease has the potential to improve the prognosis of selected patients with metastatic cancer.

Adult↗
PubMed1992

[Importance of lipoprotein(a) in patients with ischemic heart disease].

Elevated levels of lipoprotein(a) [Lp(a)] have been associated with an increased risk of ischemic heart disease (IHD), and higher levels of Lp(a) are associated with lesions of significantly greater severity. We have examined Lp(a), total cholesterol (TC) and high density lipoprotein-cholesterol (HDL-C) levels in patients with IHD including those with normal coronary arteries with vasospastic angina. The study population consisted of 206 patients (166 males and 40 females) who underwent diagnostic coronary angiography for known IHD. Twenty-eight patients had effort angina, 36 rest angina, 8 unstable angina and 134 old myocardial infarction. IHD patients were categorized as zero vessel disease (0VD), single vessel disease (SVD) and multi-vessel disease (MVD). To investigate the relationship between atherosclerosis and IHD, these patients were further divided into 3 groups based on angiographic findings. Eighteen patients had entirely normal coronary arteries (normal group), 24 discretely diseased coronary arteries (discrete group) and 80 diffusely diseased coronaries (diffuse group). The results were compared with those obtained from 50 healthy individuals. Lp(a) levels for IHD patients (12.4 mg/dl) were significantly higher than those of controls (7.1 mg/dl, p < 0.05). However, there were no statistical differences between 0VD (13.1 mg/dl) and MVD (12.8 mg/dl). Similarly, no statistical differences of Lp(a) values were found among the normal group (13.3 mg/dl), discrete group (12.0 mg/dl) and diffuse group (12.9 mg/dl). Mean levels of HDL-C in 0VD (51.3 +/- 13.5 mg/dl) were significantly higher than those of SVD (42.9 +/- 11.5 mg/dl, p < 0.05). However, no significant differences were observed between controls (59.5 +/- 15.3 mg/dl) and 0VD (51.3 +/- 13.5 mg/dl).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

A case of melena caused by a hepatic aneurysm ruptured into the intrahepatic bile duct in a patient with allergic granulomatous angiitis.

A 46 year old woman was admitted to our institute in June, 1987 with an attack of asthma, as well as remittent fever and leukocytosis accompanied by hypereosinophilia. She was found to have melena from an unknown source upon gastrointestinal examination. Four low-density areas were found in the liver on computed tomography and one of the intrahepatic foci formed a large extrahepatic abscess communicating with the intrahepatic duct on tubography. Resection of the four hepatic segments, including the large abscess, and cholecystectomy were performed. Healed necrotizing arteritis was histopathologically observed in the resected liver specimen, with the four low-density areas on CT scan having all been necrotic foci. One of them formed an intrahepatic biliary fistula and rupture of a hepatic aneurysm into a biliary duct was found to be the cause of melena. Although eosinophil infiltration and extravascular granuloma were not observed, a diagnosis of allergic granulomatous angiitis was made from the characteristic clinical course, systemic vasculitis and peripheral blood eosinophilia. To the best of our knowledge, this is the first report of intrahepatic duct perforation most probably being caused by hepatic aneurysm rupture in a patient with allergic granulomatous angiitis.

Aneurysm↗
PubMed1991

Visual load of working with visual display terminals--introduction of VDT to newspaper editing and visual effect.

In the Japanese newspaper industry, since the late 1970s, computerization has been started in large scale. The system, called Computerized Typesetting System (CTS), has been introduced. With this system, all information in the newspaper is input into a computer, called up on a cathode ray display (CRT) to edit, and then output to film or printing plates by CTS. Thus, the work of newspaper production has undergone a major transformation from industrial work to clerical work. It was reported that newspaper production staff working with VDTs complained more than staff working with the older key system about visual and physical problems which affected their job and their daily life. The complaint rates were highest for editors, who used VDT constantly throughout the day. This study was performed to clarify the health impact of VDT use and to prevent health disorders caused by the introduction of CTS. It is concluded that 5 m corrected vision and sphere refraction of CTS workers who used CTS over 2 or 4 hr daily, significantly became worse in a year after the introduction. Therefore, it is indicated that the control of CTS work time is important to prevent the visual disorder.

Adult↗
PubMed1990

A three-dimensional method for calculating currents induced in bodies by extremely low-frequency electric fields.

A user-friendly, numerical program has been developed to permit the calculation of induced currents in modeled bodies of human and infrahuman subjects. The program is based on a charge-simulation method (CSM), and it takes into account the three-dimensional (3-D) character of the extremely-low-frequency (ELF) electric field and of the models to be exposed. The principle of the method is to simulate a 3-D object, for example, an animal model, by a combination of several parts (blocks) having simple geometric forms such as a sphere, a cylinder, or a cone. This approach permits easy preparation of input data on the dimensions of the blocks and their positions in a 3-D arrangement. Other input data, such as the coordinates of the contour points and the imaginary values of charges inside objects, which are necessary in the calculations by CSM, are produced automatically by selecting an appropriate "level" for each block, according to its importance. To simulate parts having irregular shapes, special blocks may be added. In one series of experiments, induced currents were calculated for a baboon model in various postures: standing upright, positioned on four legs, and sitting on the floor. Calculated currents, the total induced current in particular, agreed very well with experimental values. Local currents in parts of the baboon models were more variable, ranging from 5% to 17% of measured values in the case of induced currents in the head. Some problems with this method, such as the effect of the dimensions of blocks or the choice of block levels, are discussed.

Animals↗
PubMed1990

Immunohistochemical and histometrical studies of the human thymus with special emphasis on age-related changes in medullary epithelial and dendritic cells.

Age-related changes in medullary epithelial and dendritic cells in the human thymus were examined quantitatively using immunohistochemistry and histometry. The material used was thymic biopsy specimens obtained from 105 patients during cardiac surgery, none of whom had immunological abnormalities. By using keratin and tissue polypeptide antigen markers to identify epithelial cells and S-100 protein and LN-2 markers to identify dendritic cells, the numbers of these cells in the medulla were counted morphometrically. The relative proportions of the cortex, medulla, Hassall's bodies, perivascular space, connective tissue and fatty tissue were evaluated using a computer image-analysis system and the respective relative volumes were calculated. Our results indicate that the number of medullary dendritic cells/mm2 and the relative volume of cortical thymocytes decrease steadily up to the age of 40 years, whereas no major change was found in the number of medullary epithelial cells/mm2.

Adolescent↗
PubMed1989

ELF electromagnetic environment in power substations.

This paper presents a theoretical analysis of electromagnetic environments in power substations in service. A new analytical method is developed and applied to magnetic field calculations in 187-kV and 66-kV substations. Experimental results verify that the method offers a good prediction of the magnetic field profiles in the substations except for the areas where localized field sources exist. The analytical results show that the magnetic field strength depends to a great extent on how the load powers distribute on individual lines and buses, that the magnetic fields in substations have a three-dimensional characteristic, and that the predominant field component depends on the position of interest. Moreover, it is suggested that objects placed in substations are exposed not only to magnetic fields of high strength in comparison to those in houses or near the distribution networks but also to fields with several percent of harmonic distortion.

Electromagnetic Fields↗
PubMed1989

[Roentogenologic pathologic evaluation of allograft rejection in heart-lung transplantation--an experimental study in Japanese monkey].

Experimental heart-lung transplantation was carried out in Japanese Monkey (Macaca fuscata). Twelve monkeys survived two to thirty-three days. Pathologic examination of the lung was performed at the time of open lung biopsy and autopsy. Postoperative chest roentogenogram was also studied in seven monkeys. In the early postoperative period, central cloudiness and enhancement of the interstitial change were observed, which started from the second or third postoperative day and reached their peak between the fifth and eighth postoperative day. Pathological study revealed no obvious monocyte infiltration in the lung of this stage. Two types of pulmonary rejection were observed, one is alveolar and vascular rejection. The other is vascular type of rejection, which started as early as in the twelfth postoperative day in a case. In the former, consolidation of the lung was noticed and useful in the diagnosis, but in the latter, no distinct change was observed in plain chest roentogenogram.

Animals↗
PubMed1989

Coronary arteriovenous fistula with vasospastic angina.

A 50-year-old man was admitted to our hospital because of chest pain. Twenty-four-hour ECG recording demonstrated ST-segment depression and elevation at the time of spontaneous angina. During treadmill exercise test, the patient developed chest pain with ST-segment depression in leads V4 to V6. After the administration of nifedipine (10 mg), the patient was able to reach up to the maximum predicted heart rate without anginal symptoms and ST-T changes. Coronary arteriogram demonstrated 50% stenosis at the proximal portion of the left anterior descending artery (LAD) and two small fistulas originated from LAD to pulmonary artery. Spasm was induced at the proximal portion of LAD by the hyperventilation. If patients with coronary arteriovenous fistula (CAVF) have symptoms, elective CAVF ligation has been recommended. However, this case suggests that coronary spasm could be one of the cause of angina pectoris in patients with CAVF. Elective CAVF ligation must be carefully indicated in CAVF patients with angina pectoris.

Angina Pectoris↗
PubMed1989

Detection of anti-cerebral autoantibodies in schizophrenia and Alzheimer's disease.

Autoantibodies to cerebrum were investigated in the sera from schizophrenia, Alzheimer's disease and healthy subjects by indirect immunofluorescence method. Four patterns of staining were observed: type A (neuronal cell), type B (blood vessel), type C (nucleus) and type D (glia and miscellaneous cell). Among rat, guinea pig and rabbit cerebrum, rabbit cerebrum proved best (low non-specific binding and high sensitivity) for the detection of circulating autoantibodies to cerebrum. With schizophrenia, 13 out of 46 cases (28.3%) were positive for autoantibodies to neuronal cells and 6/13 of those were not absorbed by liver acetone powder. With Alzheimer's disease, 25/63 (39.7%) were positive for autoantibodies to neuronal cells and 6/25 were not absorbed by liver acetone powder.

Alzheimer Disease↗
PubMed1988

Reticular meshwork of the spleen in rats studied by electron microscopy.

The reticular meshwork of the rat spleen, which consists of both fibrous and cellular reticula, was investigated by transmission electron microscopy. The fibrous reticulum of the splenic pulp is composed of reticular fibers and basement membranes of the sinuses. These reticular fibers and basement membranes are continuous with each other. The reticular fibers are enfolded by reticular cells and are composed of two basic elements: 1) peripheral basal laminae of the reticular cells, and 2) central connective tissue spaces in which microfibrils, collagenous fibrils, elastic fibers, and unmyelinated adrenergic nerve fibers are present. The basement membranes of the sinuses are sandwiched between reticular cells and sinus endothelial cells and are composed of lamina-densalike material, microfibrils, collagenous fibrils, and elastic fibers. The presence of these connective tissue fibrous components indicates that there are connective tissue spaces in these basement membranes. The basement membrane is divided into three parts: the basal lamina of the reticular cell, the connective tissue space, and the basal lamina of the sinus endothelial cell. When the connective tissue space is very small or absent, the two basal laminae may fuse to form a single, thick basement membrane of the splenic sinus wall. The fibrous reticulum having these structures is responsible for support (collagenous fibrils) and rebounding (elastic fibers). The cells of the cellular reticulum--reticular cells and their cytoplasmic processes, which possess abundant contractile microfilaments, dense bodies, hemidesmosomes, basal laminae, and a well-developed, rough-surfaced endoplasmic reticulum, and Golgi complexes, which are characteristic of both fibroblasts and smooth muscle cells--are considered to be myofibroblasts. They may play roles in splenic contraction and in fibrogenesis of the fibrous reticulum. The contractile ability may be influenced by the unmyelinated adrenergic nerve fibers that pass through the reticular fibers. The three-dimensional reticular meshwork of the spleen consists of sustentacular fibrous reticulum and contractile myofibroblastic cellular reticulum. This meshwork not only supports the organ but also contributes to a contractile mechanism in circulation regulation, in collaboration with major contractile elements in the capsulo-trabecular system.

Animals↗
PubMed1988

Distribution of Ito cells in experimental hepatic fibrosis.

Ito cells (FSC) have been thought to be collagen-producing cells with regard to hepatic fibrosis. We have found that desmin, a structural protein of muscular intermediate filaments, is found in the cytoplasm of FSC, even in negative vitamin A-autofluorescence FSC, by using immunocytochemical techniques. In the present study, numbers of FSC produced by the administration of heterogeneic serum or carbon tetrachloride were detected in fibrous and non-fibrous areas of hepatic lobules by using a morphometrical analyser. After 8 weeks of intraperitoneal injections of heterogeneic serum into rats, FSC in fibrous septa increased in number and the increase continued to 12 weeks-although the numbers of FSC in non-fibrous areas and in controls given homologous serum did not change during the experiment. In the case of rats administered CCl4 once, FSC in fibrous areas increased in numbers after 48 h through 72 h, although the number of FSC in non-fibrous areas and in controls did not change. The results, with an apparent increase in numbers of FSC in fibrous areas and no change in non-fibrous areas, showed the possibility of hyperplasia due to cell division of FSC in the new fibroplastic areas.

Animals↗