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Biomedical subjects

Y Soma

Publications and source records attributed to Y Soma.

At least 145 records · Page 8Linked to original sources
PubMed1989

[Interhemispheric visual information transfer in callosal agenesis].

It has been well established that acquired lesions of the corpus callosum such as surgical section bring about disturbances of interhemispheric transfer of visual information. In contrast, patients with callosal agenesis do not display these specific deficits. The mechanisms of this compensation have been postulated as follows; (1) bilateral development of language function, (2) exploitation of extracallosal commissure fibers such as the anterior commissure. Several studies have reported, however, minor disturbances of interhemispheric visual transfer in callosal agenesis, such as less efficient interhemispheric transfer of complex visual stimuli (Gott & Saul, 1978), slower reaction time in interhemispheric comparison of visual stimuli (Sauerwein & Lassonde, 1983), or deficits in spatial localization in the right hemi-field (Martin, 1985). In order to settle these issues, we have administered four kinds of tachistoscopic visual recognition tests on 4 patients with complete agenesis of the corpus callosum confirmed by magnetic resonance imaging (MRI). This technique enabled us to see the mid-sagittal plane of the corpus callosum and diagnose its total absence with much higher certainty and precision than previous studies employing computed tomography (CT) or pneumoencephalography. Case 1: A 41-year-old right-handed man visited us because of recurrent numbness in the four extremities. Neurological examination revealed no abnormalities. MRI has confirmed that the corpus callosum was totally lacking, and that the anterior commissure was normally visualized. Case 2: A 31-year-old right-handed man was referred to us for the treatment of partial complex seizure. Total agenesis and lipoma of the corpus callosum was diagnosed by MRI and reconstructed sagittal view of CT scan.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[A case of biventricular assist with centrifugal pumps after operation of ventricular septal perforation following acute myocardial infarction].

We applied biventricular assist using centrifugal pumps on a 64-year-old male who has undergone an operation against post-myocardial infarction with ventricular septal perforation. The pump flow was maintained at the level of 2.5 l/m2 in CI, and the pulse pressure 30 to 50 mmHg with IAPB. Complete hemostasis has been achieved prior to use heparin to control the patient's ACT around 200 sec. on the third pumping day. The patient's cardiac function improved in a few days at the beginning, but did not recover enough for weaning from the assist devices. He died on the 8th pumping day, and the autopsy revealed massive old myocardial infarction which is considered to be the major obstacle against the recovery of the cardiac function. There was no edema in any organs. Centrifugal pumps are very useful for ventricular assist in availability and in economy. Its efficacy is comparable with pulsatile ventricular assist devices especially when applied with IABP though there still exists controversy as for the superiority of pulsatile flow in ventricular assist.

Assisted Circulation↗
PubMed1989

[The prognosis and the surgical indications of DeBakey type III dissecting aortic aneurysm].

In order to determine the indications of operation for dissecting aortic aneurysm of DeBakey type III, therapeutic results obtained from 60 cases (11 with type IIIa and 49 with type IIIb) treated at our department during the 19-year period until the end of 1984 were analyzed as well as their distant prognosis. Since 12 cases (20%), who visited our department during the acute phase, were all abated to the subacute phase by hypotensive treatment, and since only one of the 12 cases died from pneumonia 5 weeks after the onset, it was thought that the operation during the acute phase is in most cases not necessary. We applied operation when there was a large false lumen, a regional protrusion, rupture or impending rupture. Out of the 60 cases, 25 (42%; 7 with type IIIa and 18 with type IIIb) underwent operation, and 3 of them (12%), including one ruptured case during the chronic phase, died due to the operation. Among cases with type IIIa, a non-operated case died of a related cause (rupture) during distant period, but none of operated cases died. Among discharged cases with type IIIb, 4 of 16 operated cases (25%) died of related causes during distant periods. This mortality did not differ from that of non-operated cases; namely, 8 of 30 non-operated cases died (27%). A 5-year survival rate was also identical between the non-operated and operated cases with type IIIb; namely, about 50% in the 2 groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Biological versus mechanical valves in the mitral position].

The long-term late results of isolated mitral valve replacement before April 1981 were retrospectively evaluated in 54 patients receiving a Hancock valve (HX) with a total follow-up of 424 patient-years (py) and 37 patients receiving a Björk-Shiley valve (BS) with a total follow-up of 366 py. There was no significant difference in regard to preoperative age, cardiothoracic ratio, electrocardiogram, or New York Heart Association functional class between the two groups. All of the BS group and 43 of the HX patients received long-term anticoagulant therapy. No significant difference was notable between the two groups in hospital mortality. Actuarial survival rate excluding hospital deaths was 75.5 +/- 6.7% for the HX group, and 80.8 +/- 7.1% for the BS group at ten years (not significant). There was no significant difference between the two groups in overall incidence of thromboembolism (HX 1.4% py, BS 1.9% py), anticoagulant related bleeding (HX 0.5% py, BS 0.8% py), or endocarditis (HX 0.5% py, BS 0.3% py). Actuarial freedom from reoperation at ten years was 69.6 +/- 8.1% for the HX group, and 93.5 +/- 4.4% for the BS group (p less than 0.01). Event free survival excluding hospital deaths at ten years was 49.2 +/- 8.1% for the HX group, 70.6 +/- 8.3% for the BS group (p less than 0.05). We prefer a mechanical prosthesis except in patients over 65 years old, who have a short life expectancy, in whom anticoagulation is thought to be difficult, and who hope a biological valve.

Adult↗
PubMed1989

A clinical study of cerebral circulation during extracorporeal circulation.

The objective of this study is to clarify the relationship of cerebral blood flow to extracorporeal circulation flow and mean arterial pressure during nonpulsatile extracorporeal circulation under moderate hypothermia. Cerebral blood flow was determined by an argon saturation and desaturation method after that of Pevsner and colleagues with a mass spectrometer in 21 adult patients undergoing cardiac operations. Cerebral blood flow was 25, 33, 35, and 42 ml/100 gm/min, ranging from 19 to 50 ml/100 gm/min, at extracorporeal circulation flow rates of 40, 50, 60, and 70 ml/kg/min, respectively. Cerebral blood flow increased proportionally to extracorporeal circulation flow. Cerebral blood flow scattered almost transversely to mean arterial pressure and was 31 ml/100 gm/min in a hypotensive group (mean arterial pressure 34 to 50 mm Hg) and 34 ml/100 gm/min in another group (mean arterial pressure 51 to 94 mm Hg). Mean arterial pressure did not significantly influence cerebral blood flow. Cerebral oxygen consumption did not remarkably decrease and remained in the reasonable range when cerebral blood flow was 23 to 40 ml/100 gm/min. Subsequently, we assumed that the average cerebral blood flow value of 25 ml/100 gm/min at an extracorporeal circulation flow rate of 40 ml/kg/min also would be in the safe range. All of the patients are living without cerebral complications. We conclude that (1) cerebral blood flow was extracorporeal circulation flow dependent and (2) cerebral blood flow in the safe range was maintained even in the hypotensive range, provided the extracorporeal circulation flow rate was 40 ml/kg/min or higher.

Adolescent↗
PubMed1988

Effect of lymphotoxin and tumor necrosis factor on endothelial and connective tissue cell growth and function.

In an approach to understand the immune basis of human vascular and fibrotic disorders, the effects of recombinant human tumor necrosis factor alpha (rTNF) and lymphotoxin (rLT) on the in vitro growth and function of vascular and connective tissue cells were studied. Both rTNF and rLT stimulated fibroblast growth and protein, fibronectin, and collagen synthesis in dose-dependent fashion. In contrast, endothelial cell (EC) growth was inhibited by both cytokines; true EC cytotoxicity was seen at high concentrations (greater than or equal to 500 mu/ml). Addition of recombinant interferon-gamma markedly enhanced EC cytotoxicity while the growth factor beta-transforming growth factor reversed EC growth inhibition. Both rTNF and rLT stimulated factor VIII-Ag synthesis by EC. These contrasting effects of rTNF and rLT on fibroblast and endothelial cell growth and function in vitro are intriguing because they are the same contrasting effects observed in vivo in connective tissue and vascular disorders, raising the possibility of a role for these cytokines in these disorders. Study of the in vitro and in vivo mechanisms of these diverse effects may contribute to the understanding of certain human disorders characterized by endothelial injury and fibroblast activation leading to fibrosis.

Animals↗
PubMed1987

Immunohistochemical detection of the placental form of glutathione S-transferase in dysplastic and neoplastic human uterine cervix lesions.

Expression of the human placental form of glutathione S-transferase (GST-pi) in dysplasia (53 cases), carcinoma in situ (10 cases), and invasive carcinoma (46 cases) of human uterine cervix was investigated immunohistochemically with specific anti-GST-pi rabbit antibody. While normal squamous epithelium was largely negative, the binding of antibody was appreciable in mild and moderate dysplasias, especially in the cytoplasm of cells demonstrating koilocytotic atypia. In severe dysplasia, the nuclei as well as the cytoplasm were strongly stained in all cell layers except for the superficial layer, and in carcinoma in situ both of them were also strongly stained in all cell layers. In invasive carcinoma, over 90% of cases exhibited strong cytoplasmic staining and in over 70% the nuclei were positive. GST activity towards 1-chloro-2,4-dinitrobenzene and GST-pi protein content were significantly increased in all of 4 squamous cell carcinomas examined as compared to values for normal cervical epithelia. Two-dimensional gel electrophoresis followed by immunoblotting using the GST-pi antibody demonstrated that, of many cytoplasmic proteins, only the GST-pi subunit was specifically bound. These results indicate that GST-pi is a potentially useful immunohistochemical marker for (pre)neoplasia of human uterine cervix. In addition, it was demonstrated that the cells in severe dysplasia, carcinoma in situ, and invasive carcinoma expressing GST-pi were often characterized by staining with a monoclonal antibody to the v-H-ras gene product.

Female↗
PubMed1987

Purification and characterization of glutathione S-transferases in human kidney.

Four glutathione S-transferase (GST, EC 2.5.1.18) forms were purified from human kidney by S-hexylglutathione affinity chromatography followed by chromatofocusing using a fast protein liquid chromatography system. These forms were demonstrated to be identical with GSTs I, II, IV, V(pi) in human liver previously characterized by us, by SDS-polyacrylamide slab gel electrophoresis, two-dimensional gel electrophoresis and double immunodiffusion. GST III (mu) was not detected in any of 5 specimens examined. GST-pi was a major form in the kidney. The activity was 30-40% of the total activity in kidney cytosol and the protein amount was approximately 140 micrograms/g of tissue; 0.27% of the total cytosol protein amount. In many organs including the placenta, GST-pi is present at levels similar to that in the kidney but low in the liver (34 micrograms/g).

Adult↗
PubMed1987

[A case of pseudoxanthoma elasticum showing various heteroptics due to infarction of right parieto-occipital lobe].

A case of pseudoxanthoma elasticum showing various heteroptics due to infarction of the right parieto-occipital lobe was reported. The patient was 48-year-old male. Angiography revealed an obstruction of the right internal carotid artery, aneurysmal dilation of the right posterior communicating artery, and obstructions of the right parieto-occipital artery and calcarine artery. A low density area was found in right occipital lobe by CT. MRI clearly identified lesions in the right cuneus and precuneus. Pseudopsia in the left homonymous quadrantanopsia, various types of visual illusion in the remaining visual field, and moreover, palinopsia were existed. Visual illusion was recognized in the early stage after the onset, while the pseudopsia was recognized about one month after the onset. Both abnormalities tended to improve from the peripheral region with the improvement of the defect in the visual field. Administration of phenytoin resulted in an improvement in the pseudopsia but it resulted in an aggravation in the visual illusion. Thus, the mechanisms of development of this phenomena were thought to be different from each other. It was found by dynamic CT that the blood flow in the primary visual cortex was rather increased in the affected site in comparison with that in the healthy site. It was speculated that the pseudopsia in the defective region of the visual field reflected a pathological repair process represented by a development of the collateral circulation. On the other hand, the visual illusion was thought to originate from visual unstability due to incomplete damage of the visual pathway at the affected site.

Cerebral Infarction↗
PubMed1986

Purification and subunit-structural and immunological characterization of five glutathione S-transferases in human liver, and the acidic form as a hepatic tumor marker.

Five glutathione S-transferase (GST, EC 2.5.1.18) forms were purified from human liver by S-hexylglutathione affinity chromatography followed by chromatofocusing, and their subunit structures and immunological relationships to rat liver glutathione S-transferase forms were investigated. They were tentatively named GSTs I, II, III, IV and V in order of decreasing apparent isoelectric points (pI) on chromatofocusing. Their subunit molecular weights assessed on SDS-polyacrylamide gel electrophoresis were 27 (Mr X 10(-3)), 27, 27.7,27 and 26, respectively, (26, 26, 27, 26, and 24.5 on the assumption of rat GST subunit Ya, Yb and Yc as 25, 26.5 and 28, respectively), indicating that all forms are composed of two subunits identical in size. However, it was suggested by gel-isoelectric focusing in the presence of urea that GSTs I and IV are different homodimers, consisting of Y1 and Y4 subunits, respectively, which are of identical Mr but different pI, while GST II is a heterodimer composed of Y1 and Y4 subunits. This was confirmed by subunit recombination after guanidine hydrochloride treatment. GST III seemed to be identical with GST-mu with regard to Mr and pI. GST V was immunologically identical with the placental GST-pi. On double immunodiffusion or Western blotting using specific antibodies to rat glutathione S-transferases, GST I, II and IV were related to rat GST 1-1 (ligandin), GST III(mu) to rat GST 4-4 (D), and GST V (pi) to rat GST 7-7 (P), respectively. GST V (pi) was increased in hepatic tumors.

Adult↗
PubMed1986

Human placental form of glutathione S-transferase (GST-pi) as a new immunohistochemical marker for human colonic carcinoma.

Human placental form of glutathione S-transferase (GST-pi) was detected in human colonic carcinomas and adenomas by peroxidase anti-peroxidase method using antibody raised against GST-pi. Of 60 carcinomas, including differentiated adenocarcinomas and undifferentiated carcinomas, 88% were positive for GST-pi staining, and 47% of 23 adenomas were also positive. In the normal colonic mucosa, GST-pi was not detectable or was only weakly stained in the basal parts of the absorptive cells or in the cytoplasm of the cells containing little mucin. These results indicate that GST-pi is a possible new marker for immunohistochemical detection of human colonic carcinoma and some adenomas.

Adenoma↗
PubMed1985

Purification, induction, and distribution of placental glutathione transferase: a new marker enzyme for preneoplastic cells in the rat chemical hepatocarcinogenesis.

A polypeptide of Mr 26,000 and pI 6.7 that was markedly increased in rat livers bearing hyperplastic nodules (HNs) induced by chemical carcinogens was identified immunochemically as the subunit of neutral glutathione (GSH) transferase (GSHTase; RX:glutathione R-transferase, EC 2.5.1.18; also called GSH S-transferase) purified from placenta (GSHTase-P) and was demonstrated immunohistochemically to be localized in preneoplastic foci and HNs. In the present study, GSHTase-P has been purified from the HN-bearing liver, and the distribution and inducibility have been examined quantitatively using anti-GSHTase-P antibody. Elevation of GSHTase-P in the HN-bearing livers was also confirmed by in vitro translation of mRNAs isolated from the HN-bearing livers. The purified GSHTase-P was homogeneous in size but had two charge isomers on two-dimensional gel electrophoresis. In normal tissues, including liver, placenta, and fetal liver, the protein content of GSHTase-P was generally low but was significantly high in kidney and pancreas. In contrast, the amount of GSHTase-P in HN-bearing livers (primary hepatomas) and transplantable Morris hepatoma 5123D were several 10-fold higher than that in normal liver but were undetectably low in transplantable Yoshida ascites hepatoma AH 130. Different from ordinary drug-metabolizing enzymes, GSHTase-P was uninducible by administration of drugs and carcinogens prior to appearance of the preneoplastic foci and HNs. In addition, species specificity of GSHTase-P was low as it was crossreactive among rat, hamster, and human.

Amino Acids↗