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Biomedical subjects

Y Usui

Publications and source records attributed to Y Usui.

At least 109 records · Page 6Linked to original sources
PubMed1989

[Radiological findings of cancerous invasion in colorectal cancer less than 3 cm in diameter].

131 colorectal cancers, less than 3 cm in diameter, experienced at Juntendo University Hospital in Oct. 1977 through Dec. 1988 were studied with respect to their radiological and macroscopic features. Macroscopic features of the cancers were classified into type a (a lesion with a long stalk), type b (a subpedunculated or sessile lesion), type c (a plaque-like lesion) and type d (a lesion with a depression). Type a is early cancer. An early cancer of type b was mostly demonstrated as a lobular pattern of tumor surface, and an advanced cancer as a nodular pattern. Type c less than 1 cm in diameter was seen a sm cancer. A sm cancer of type d was mostly demonstrated as a faint barium fleck of the depression, an advanced cancer as a mild barium fleck. By deformed colonic wall in profile view, an early cancer was mostly demonstrated as a thorn shape deformity, sm or pm cancer as an arch shaped deformity and a cancer with deeper cancerous invasion than pm as a trapezoid deformity.

Colorectal Neoplasms↗
PubMed1989

[A case of chronic renal hemodialysis and intracranial hypertension--a study on CSF dynamics].

There are many reports on the disequilibrium syndrome due to dialysis in patients with chronic renal failure. However, they do not mention the findings of CT cisternography and MRI. We intend to investigate the mechanism of CSF dynamics in a patient with disequilibrium syndrome by means of these radiological examinations. A 31 year-old woman who had suffered from renal failure for 18 years was found to have prominent increase of serum creatinine (18.1 mg/dl) and BUN (127 mg/dl) 3 years ago. At that time, digital marking of the skull was already present by X-ray examination without other destruction in bone survey of the whole body. She was hemodialysed by the hollow fiber kidney three times weekly (dialysis time 4.5 hours, dialysate osmotic pressure 270 mOsm/kg H2O). Three months ago, she began to complain of severe headache, nausea and vomiting 2 hours after the beginning of dialysis, so that she was referred to Kosei Hospital. On admission, she showed exophthalmus, concentric narrowing of the visual field, optic atrophy and hyperreflexia in jaw and four extremities. After admission, she received hemodialysis therapy thrice weekly (dialysis time 5 hours, dialysate osmotic pressure 290 mOsm/kg H2O). At the same time, 200 ml of glycerol (contents of glycerin 10, fructose 5, NaCl 0.9%) was administered intravenously during dialysis, which ameliorated the symptoms of intracranial hypertension. Laboratory studies revealed marked decrease of serum creatinine, BUN and uric acid levels and osmotic pressure, and increase of blood pH at the time of postdialysis compared with predialysis. Manometric CSF pressure increased up to 310 mmH2O at the day without dialysis before the glycerol administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Effect of healing on compliance of porous Dacron grafts.

The effects of tissue ingrowth on the compliance of porous Dacron grafts were studied in 8 mm external-velour warp-knit Dacron grafts implanted in the canine descending thoracic aorta. The compliance of these grafts was measured before implantation and after implant periods of two weeks and one, two, four, and six months. Compliance, which initially was 0.043 +/- 0.008% mm Hg, decreased less than 10% after implantation (no statistical difference at p less than 0.05). No anastomotic neointimal hyperplasia was observed. Although the total thickness of the graft wall increased two- to three-fold after implantation, the benign healing process observed in this study had very little influence on graft compliance followed to six months.

Animals↗
PubMed1988

[An autopsy case of gastric metastasis simulating linitis plastica carcinoma from primary linitis plastica carcinoma of the rectum].

Cases of a metastatic involvement of the stomach from a colorectal cancer are extremely rare, and once such case, confirmed by autopsy, is reported. The patient, an 86-year-old woman, had a metastatic lesion of the stomach from a rectal cancer. The rectal cancer was a combined linitis plastica type and signet ring cell carcinoma, and the appearance of metastatic lesion of the stomach had simulated the linitis plastica type cancer. A metastatic involvement of the stomach presenting a linitis plastica type cancer from a breast cancer is well documented, but a linitis plastica type from a colorectal cancer has not been reported. This case is the first report concerning a gastric metastasis presenting linitis plastica type lesion from a colorectal cancer.

Adenocarcinoma, Scirrhous↗
PubMed1988

[Healing of an external velour warp-knit Dacron vascular prosthesis].

An external velour warp-knit Dacron vascular prosthesis (8mm in internal diameter, 6cm in length), whose porosity is 1200cc/cm2/min at 120mmHg, was implanted in the descending thoracic aorta of 30 mongrel dogs. The dogs were sacrificed at different intervals between 2 weeks and 6 months. All grafts were patent at sacrifice and no serious complication was observed. Thrombus free surface score was about 90%. Cell coverage on the flow surface was first observed near anastomoses in 1-month specimens and was almost completed in 2 months. Transinterstices healing was completed in 2 months. This excellent healing in a canine model would allow clinical availability of this graft.

Animals↗
PubMed1988

Differences in reendothelialization after balloon catheter removal of endothelial cells, superficial endarterectomy, and deep endarterectomy.

The process of reendothelialization was studied in a deendothelialized 3 cm segment of the canine descending thoracic aorta from which peripheral endothelial cell ingrowth had been prevented by impervious prosthetic graft sleeves. Three preparations were studied: (1) removal of only the endothelial cells, accomplished by flow surface drying and balloon catheter denudation, (2) removal of the superficial portion of the nonvasal media, accomplished by endarterectomy to a depth of 200 to 300 micron, and (3) removal of the entire inner (nonvasal) media, accomplished by endarterectomy to a depth of 500 to 600 micron to reach the outer (vasal) media. A total of 44 specimens were studied after implantation periods of 7, 14, 28, and 56 days. In all cases endothelial cell ingrowth from the host aorta into the test specimen was prevented by the impervious graft sleeves. In the deep endarterectomy group there were scattered areas of reendothelialization at 1 week, extensive reendothelialization at 2 weeks, almost complete reendothelialization at 4 weeks, and confluence by 8 weeks. However, in the superficial endarterectomy group scanning electron microscopy showed scattered areas of factor VIII/von Willebrand factor (FVIII/vWF)-negative, endothelial-like cells at 4 weeks, whereas at 8 weeks most of the surface was covered by endothelial cells identified by FVIII/vWF. In those specimens subjected to balloon catheter removal of endothelial cells only, reendothelialization was not seen, even at 8 weeks.

Animals↗
PubMed1987

A comparative experimental study of the organization of arterial and venous thrombi.

Organization of a venous thrombus proceeds much faster than that of an arterial thrombus. Two different double-ligation procedures were used for study of the time sequence of thrombus organization by the vascularized (in situ) and devascularized (dissected) walls of the external jugular vein and common carotid artery in 21 mongrel dogs. Blood in the ligated segments of the in situ veins remained mostly fluid. In these segments, intimal hyperplasia was observed after 4 weeks with apparent preservation of an endothelial lining. However, in the dissected veins, the trapped blood rapidly thrombosed. Remarkable cell proliferation quickly occurred in these dissected walls with rapid invasion of the thrombus to achieve complete organization by 4 weeks. In contrast, a thrombus formed in the ligated segments of all arteries, whether in situ or dissected, and organization was much slower, requiring about 4 months for completion. Full-wall viability was maintained in 100% of the in situ veins and in 95% of the devascularized veins, but inner wall viability was lost in 30% of the in situ arteries and in 95% of the devascularized arteries.

Animals↗
PubMed1987

Platelet aggregation by group B streptococci.

Forty-six strains of group B streptococci (GBS), including various serotypes and non-serotypable strains, were tested for their ability to induce platelet aggregation in human platelet-rich plasma; four strains, all belonging to type III, showed a positive reaction. The characteristics of the reaction were investigated in these four positive strains. Aggregation was dependent on the ratio of bacteria to platelets, being maximal at a ratio of 4.3. Platelet aggregation was inhibited by EDTA (100% inhibition at 3.1 mM), indomethacin (100% inhibition at 10 mM), acetylsalicylic acid (93-100% inhibition at 5.0 mM) and quinacrine (100% inhibition at 0.25 mM). Thus the reaction was cation-dependent and required cyclooxygenase activity. Assays for cytosolic lactate dehydrogenase did not indicate platelet lysis. GBS induced the release of [3H]serotonin, which was maximal (68-78%) at 10 min after the reaction was started. Experiments with gel-filtered platelets suggested that GBS-induced platelet aggregation required both fibrinogen and heat-resistant (56 degrees C, 30 min) serum factors. Type-specific antisera prevented the platelet aggregation activity of heat-killed bacteria, but not of live bacteria. Trypsin digestion of the bacterial cells caused an almost complete loss of the platelet aggregation activity.

Aspirin↗
PubMed1987

Cell surface antigen of encapsulated Staphylococcus epidermidis ATCC 31432.

The cell surface antigen (CSA) from encapsulated Staphylococcus epidermidis ATCC 31432 was isolated and fractionated by DEAE-Sephadex ion-exchange chromatography. It yielded a single precipitin line against rabbit antiserum and was composed of galactose, glucosamine, and two (so far) unidentified carbohydrates linked to a protein backbone. Glycerol could not be detected. In an experimental mouse infection, CSA showed some protective activities, enhancing the stimulation of granulocytes as well as the immunoglobulin M response. Apparently, CSA is different from teichoic acid.

Animals↗
PubMed1986

Healing basis and surgical techniques for complete revascularization of the left ventricle using only the internal mammary arteries.

Long-term follow-up data from several leading centers concerning patients undergoing coronary artery bypass clearly demonstrate the superiority of the internal mammary artery (IMA) with patency rates of 83 to 94% at 7 to 12 years compared with the saphenous vein and its patency rates of 41 to 53%. Our experimental studies provide a biological basis for understanding this difference. Thin-walled arterial autografts undergo no histological change after being implanted in the arterial system, while venous autografts undergo major changes with an initial scattered loss of endothelium and marked thickening due to a proliferative reaction. The challenge to the cardiac surgeon is to revascularize the entire left ventricle with the IMAs. We have found this possible in most patients with advanced three-vessel disease by using both IMAs either as in situ grafts or free grafts with as many sequential anastomoses as necessary to achieve full revascularization. Our use of the term in situ refers to the graft's origin from the subclavian artery as opposed to a free IMA graft arising from another site.

Aged↗
PubMed1986

Biochemical properties of fibrinogen binding protein (clumping factor) of the staphylococcal cell surface.

The staphylococcal fibrinogen binding protein of a strain of coagulase-negative Staphylococcus aureus was purified 229 fold in terms of the haemagglutination unit compared to the starting material by affinity chromatography on fibrinogen-Sepharose. By polyacrylamide gel electrophoresis in both reduced and unreduced gels, the protein showed one major band and minor bands with relative molecular masses of 62,000, 61,000, and 59,000, respectively. The isoelectric point was between 10.2 and 10.8 determined by isoelectric focusing in polyacrylamide gel. By the agar diffusion test one band was obtained against anti-whole cell rabbit serum. Amino acid analysis of fibrinogen binding protein showed glycine, glutamic acid, lysine, alanine, aspartic acid, and arginine as the major components. Protein A or teichoic acid extracted from the homologous strain did not show fibrinogen binding activity assayed by haemagglutination and anti-fibrinogen binding activity of anti-whole cell Fab. The amount of the fibrinogen binding protein to absorb the activity of anti-whole cell Fab was decreased to 1/60 of that of the starting material. Sheep red blood cells coated with the fibrinogen binding protein agglutinated in 0.001% (w/v) fibrinogen solution.

Amino Acids↗
PubMed1986

An experimental study of eight current arterial prostheses.

Eight currently used arterial prostheses with differing constructions and materials were implanted in the descending thoracic aorta of mongrel dogs. The prostheses were Gore-Tex (polytetrafluoroethylene), DeBakey Woven, Cooley Woven, Meadox Woven Double Velour, Cooley Knitted Double Velour, Microvel, Vasculour II, and Bionit II. Five series of these eight prostheses were serially implanted in heparinized subjects. During the 40 implantations, attention was focused on three major characteristics: preclotting efficiency, surgical handling characteristics, and healing. Gore-Tex is impervious to blood. The DeBakey and Cooley woven grafts are nearly so. The remaining prostheses required preclotting. The Meadox Woven Double Velour became impervious after two preclotting steps, the Cooley Knitted Double Velour and the Bionit II required three, and the Vasculour II and the Microvel required four. The surgical handling characteristics of the knitted prostheses clearly surpassed those of the DeBakey and Cooley woven and Gore-Tex prostheses. Although the Meadox Woven Double Velour prosthesis had better conformability than the nonveloured woven, the tendency of its cut edge to fray was more pronounced. Healing was much more advanced in the knitted and woven prostheses than in the Gore-Tex.

Animals↗
PubMed1986

Possible induction of disseminated intravascular coagulation in the mouse by group B streptococcal clumping factor.

A hydrochloric acid extract, the clumping factor fraction, obtained from a clumping factor-positive strain of group B streptococci, was capable of killing mice by administration after injection of heat-killed cells of group B streptococci or Escherichia coli intravenously. In mice killed between 24 and 48 h later, fibrin thrombi were observed in the renal glomeruli, as well as in the heart, lung, liver, and pancreas. These findings suggest the possible induction of disseminated intravascular coagulation by these organisms in the mouse.

Animals↗