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Biomedical subjects

Y Kamada

Publications and source records attributed to Y Kamada.

At least 91 records · Page 5Linked to original sources

Changes in the basal ganglia and thalamus following reperfusion after complete cerebral ischaemia.

We report specific changes bilaterally in the basal ganglia and thalamus following reperfusion after complete cerebral ischaemia. A 69-year-old man, resuscitated after cardiac arrest, showed symmetrical low-density lesions in the head of the caudate nucleus and lentiform nucleus on CT. MRI revealed methaemoglobin derived from minor haemorrhage in the basal ganglia and thalamus, not evident on CT. We suggest that this haemorrhage results from diapedesis of red blood cells through the damaged capillary endothelium following reperfusion.

Aged↗

Dissecting the protein kinase C/MAP kinase signalling pathway of Saccharomyces cerevisiae.

The PKC1 gene of the budding yeast Saccharomyces cerevisiae encodes a homolog of the alpha, beta, and gamma isoforms of mammalian PKC that is essential for cell growth. Loss of PKC1 function results in a cell lysis defect that is suppressed by osmotic stabilizing agents, suggesting a defect in cell wall integrity. In this study, we show that Pkc1p-depleted cells develop holes in their cell walls positioned at their bud tips, the site to which growth is focused during polarized cell growth. This result suggests that pkc1 mutants are deficient in the process of cell wall remodeling during growth. In further support of this model, cells bearing a pkc1 delta mutation, allowed to proliferate in the presence of osmotic stabilizing agents, possessed cell walls that were only 60% as thick as wild-type cell walls. This diminution in cell wall material affected both the beta-glucan layer and the mannoprotein layer. We have exploited the cell lysis defect of pkc1 mutants to identify genes that function within the same signalling pathway at points downstream of PKC1. These genes comprise a protein kinase cascade that culminates in the activation of the MAP kinase homolog Mpk1p. The proposed order of protein kinase function, based on genetic experiments, is Pkc1p to Bck1p to Mkk1/2p to Mpk1p. Consistent with the proposed model, Pkc1p selectively phosphorylates Bck1p in vitro and Mpk1p protein kinase activity requires a functional BCK1 gene.

Calcium-Calmodulin-Dependent Protein Kinases↗

[A two staged extending graft replacement for dissecting aortic aneurysm with Marfan's syndrome].

We experienced four cases of dissecting aortic aneurysms with Marfan's syndrome, in which two staged operations were performed with satisfactory results. The operations performed in the four patients were the replacement of the ascending aorta, transverse aortic arch and the entire descending thoracic aorta in DeBakey type I dissecting aortic aneurysm, replacement of the entire descending thoracic and abdominal aorta in type IIIb, replacement of the aortic valve, ascending aorta, transverse aortic arch, the entire descending thoracic and upper abdominal aorta in type I, and replacement of the total aorta including the aortic valve in type II + IIIb, respectively. There were no operative deaths, but a 42-year-old woman with DeBakey type IIIb died suddenly 2 years 11 months after the second operation. The cause of death was presumed to be due to rupture of a dissecting aneurysm (DeBakey type II). Dissecting aortic aneurysm with Marfan's syndrome must be observed carefully and corrected surgically, because the lesion is progressive and the residual dissecting aneurysm usually dilates eventually. In view of our clinical results, we conclude that the operation for dissecting aortic aneurysm with Marfan's syndrome should be performed as extensively as possible.

Adult↗

Presence of carnitine acetyltransferase in peroxisomes and in mitochondria of oleic acid-grown Saccharomyces cerevisiae.

Activity of carnitine acetyltransferase was detected in glucose- and oleic acid-grown Saccharomyces cerevisiae. Oleic acid-grown cells showed a ten-fold higher activity than glucose-grown cells. Subcellular fractionation of oleic acid-grown cells showed that carnitine acetyltransferase was present in peroxisomes, mitochondria, and cytosol. The results suggested the plausible presence of an 'acetylcarnitine shuttle' in this yeast, as in the case of an n-alkane-assimilating yeast, Candida tropicalis.

Acetyl Coenzyme A↗

Massive spinal cord necrosis associated with adult T-cell leukaemia caused by Aspergillus.

A man with adult T-cell leukaemia (ATL) underwent massive spinal cord necrosis caused by Aspergillus infection. Leukopenia due to anti-cancer chemotherapy resulted in pulmonary Aspergillus infection. The aspergilloma was reduced in size by anti-fungal chemotherapy, but paraplegia occurred. At autopsy, the pulmonary aspergilloma was encapsulated and showed no contiguous extension of the infection to the epidural or subdural spaces or spinal cord. However, at the T5 level of the spinal cord, there was marked necrosis with haemorrhage caused by Aspergillus infection, but without leukaemic cell infiltration of the spinal cord. Dichotomously branching Aspergillus hyphae filled the blood vessels of the T5 level of the spinal cord.

Aspergillosis↗

[Angiographic evaluation of reconstructed spinal arteries in thoracic aortic aneurysm surgery].

Revascularization of the spinal arteries with thoracic aortic aneurysm were performed on nineteen patients using partial extracorporeal bypass. They were 16 men and 3 women. Age range were from 33 to 70 years (mean 49.9 +/- 10.3 years). There were eleven patients of dissecting aneurysm (DeBakey type IIIb in eight patients, type I in two patients and type IIIa in one patient), and eight patients of non-dissecting thoracoabdominal aneurysm (including two patients with ruptured aneurysm). The number of revascularized spinal arteries were 60 pairs (average 3.2 pairs per each patient). The revascularized spinal arteries were localized between levels T4 and L5.36 pairs of the 60 existed between levels T8 and L2 from where the artery of Adamkiewicz arises. Seven patients (eleven spinal arteries) underwent selective angiography of the revascularized spinal arteries postoperatively, and the anterior spinal artery and the artery of Adamkiewicz was identified in three patients. Two patients died within one month, one from MOF and the another from intestinal perforation respectively (operative mortality 11.1%). One patient, with ruptured thoracoabdominal aortic aneurysm showed paraparesis postoperatively, but no paraplegia was found in any patients. We recommend that not only the artery of Adamkiewicz but also the spinal arteries at the midthoracic area from T4 to T8 should be revascularized, to prevent postoperative paraplegia. Replacing of extended thoracic aneurysm, our method (using partial extracorporeal circulation and segmental aortic clamping) was thought to prevent spinal cord ischemia.

Adult↗

Kaposi sarcoma in Okinawa.

BACKGROUND: The authors encountered six patients with Kaposi sarcoma in Okinawa; one was classic type, two were associated with adult T-cell leukemia (ATL), one was with multiple myeloma, and two were with acquired immune deficiency syndrome (AIDS). In the classic type, many nodular lesions were seen on the skin of the extremities and a few on the trunk, some of which were ulcerated. Most lesions regressed in 1.5 years. In four other patients (three without AIDS and one with AIDS), many plaques and a few nodular lesions were seen on the trunk, face, and extremities. The other patient with AIDS showed Kaposi sarcoma only in the lymph nodes and perineural tissues in the abdomen. METHODS: Immunohistochemical and lectin histochemical studies were done on deparaffinized sections and on cells cultured from small pieces of tumor mass from the classic type Kaposi sarcoma. Isolation of viruses from tumor tissue was also attempted. RESULTS: Large numbers of endothelial cells lining irregular vascular spaces, and some spindle cells showed positive reactions for Factor VIII-related antigen, Ulex europaeus 1 (UEA-1) (E.Y. Labs, Inc., San Mateo, CA), Griffonia simplicifolia (GS-1) (E.Y. Labs, Inc.) lectins, and epidermal growth factor (EGF) receptor antigen. Cytomegalovirus (CMV), hepatitis B, herpes simplex virus (HSV) 1 and 2, papillomavirus antigens, and human immunodeficiency virus (HIV) p24 core antigen were not seen in any patients, except in the patient with AIDS in whom CMV was demonstrated in tissues adjacent to the tumor (Patient 6). In cell culture, elongated spindle cells proliferated in plate and also in three-dimensional cultures. The cells were positive immunohistochemically for Factor VIII-related antigen and EGF receptor. They also stained lectin histochemically with UEA-1 and GS-1. Tube formations were demonstrated by electron microscopic study. CONCLUSIONS: Six cases of Kaposi sarcoma have been diagnosed within a short time span where this condition has previously been said to be rare. The studies suggest a vascular endothelial cell origin and growth factor regulated growth for this tumor.

Adult↗

Microscopic and immunohistological studies on intimal hyperplasia of the arterially implanted autovein graft and its anastomosis in dogs.

The fate of intimal hyperplasia of arterially implanted autovein bypass grafts and their distal end-to-side anastomoses in dogs was studied microscopically and immunohistologically. The bypass grafting was done under conditions of abnormal blood flow and high peripheral resistance. Intimal hyperplasia of the graft first became evident 7 days after implantation and the thickness increased to about 500 microns 3 months or more after the implantation. The intimal hyperplasia was related to an active proliferation of smooth muscle cells which proved positive for alpha-smooth muscle actin staining. Moreover, it was more dominant at the toe and heel of the anastomosis and moderately apparent on the floor of the host artery. The constituent elements of the hyperplastic intima at the anastomosis were fibroblast-like cells and extracellular collagen fibers which were negative for alpha smooth muscle actin staining. This study revealed that the features of intimal hyperplasia at the distal anastomosis in autovein bypass grafting differed from those of the implanted autovein graft itself; the former being related to excessive proliferation of fibroblasts and collagen fibers while the latter displayed an active proliferation of smooth muscle cells.

Animals↗

Immunoelectron microscopic localization of thiolases, beta-oxidation enzymes of an n-alkane-utilizable yeast, Candida tropicalis.

The location of acetoacetyl-CoA thiolase (T-I) and 3-ketoacyl-CoA thiolase (T-III), enzymes of the fatty acid beta-oxidation system, was studied in n-alkane-grown Candida tropicalis cells by immunoelectron microscopy using a post-embedding method with colloidal gold conjugated IgG. The deposition of gold particles for T-I was detected in the microbodies and cytoplasm and that of gold particles for T-III specifically in the microbodies. The double labeling technique confirmed that T-I and T-III occurred concurrently in a microbody and T-I also in cytoplasm. These results were consistent with the biochemical data based on subcellular fractionation and indicated that the yeast beta-oxidation system operates efficiently only in the microbodies.

Acetyl-CoA C-Acetyltransferase↗

Ca2+ regulation of phosphatidylinositol turnover in the plasma membrane of tobacco suspension culture cells.

The biochemical properties of the enzymes involved in phosphatidylinositol (PI) turnover in higher plants were investigated using the plasma membrane isolated from tobacco suspension culture cells by aqueous two-phase partitioning. Submicromolar concentrations of Ca2+ inhibited PI kinase and phosphatidylinositol 4-phosphate (PIP) kinase and stimulated phospholipase C. Diacylglycerol (DG) kinase was inhibited by Ca2+, but required a higher concentration than the physiological level. From the above results we postulate the following scheme: signal coupled activation of phospholipase C produces IP3 which induces Ca2+ release from the intracellular Ca2+ compartment, the increased cytoplasmic Ca2+ in turn activates phospholipase C and causes a further increase of the cytoplasmic Ca2+ level. This inhibits PI kinase and PIP kinase and brings about a limited supply of PIP2, the substrate of phospholipase C. Consequently, IP3 production decreases and Ca2+ mobilization ceases. Then cytosolic Ca2+ returns to the stationary level by the Ca2+ pump at the plasma membrane and at the endoplasmic reticulum and Ca2+/H+ antiporter at the plasma membrane and at the tonoplast.

1-Phosphatidylinositol 4-Kinase↗

Acute ascending necrotizing myelitis in Okinawa caused by herpes simplex virus type 2.

A case of rapidly progressing ascending myelitis was necropsied. Necrosis was present throughout the whole length of the spinal cord and involved both the grey and white matter randomly. The perivascular lymphocytic infiltration in the spinal cord in the present case was more pronounced than that in the previously reported two cases of necrotizing myelopathy associated with malignancy. Using immunoperoxidase staining the presence of herpes simplex virus type 2 (HSV 2) antigen was demonstrated. Electron microscopic examinations revealed large numbers of HSV particles in the spinal cord. HSV 2 may be a common aetiological agent of necrotizing myelopathy and myelitis in Okinawa, an HSV 2 endemic area. In the present case, the necrosis was mainly found in the spinal cord but was also observed, to a very limited extent, in the brain.

Acute Disease↗

Structural studies on a binding site for Dolichos biflorus agglutinin in the small intestine of the mouse.

Glycoproteins which bound to Dolichos biflorus agglutinin (DBA) were isolated from the small intestine of 129/Sv mice. Among oligosaccharides released from the carbohydrate moieties of the glycoproteins by endo-beta-galactosidase, the major one with N-acetylgalactosamine at the non-reducing end was isolated by QAE-Sephadex A-25 column chromatography. The structure of the oligosaccharide was elucidated to be GalNAc beta 1----4(NeuAc alpha 2----3)Gal beta 1----4GlcNAc beta 1----3Gal by compositional analysis, methylation analysis before and after mild acid hydrolysis, sequential glycosidase digestion, secondary ion mass spectrometry (SIMS), and nuclear magnetic resonance spectroscopy. The SIMS signal of m/z 1,071 was consistent with the presence of the branched sequence, GalNAc(NeuAc)GalGlcNAc, and the signal was also detected in the high-molecular-weight fraction obtained after endo-beta-galactosidase digestion. The pentasaccharide identified here has the terminal structure of ganglioside GM2, and an apparently identical one has been identified as the epitope of blood group Sda and the DBA binding site in human T-H urinary glycoprotein. Thus, the present result has extended our knowledge of the biological meaning of the oligosaccharide structure and has established that GalNAc beta 1----4(NeuAc alpha 2----3)Gal beta 1----4GlcNAc is a DBA binding site in the small intestine of the mouse.

Animals↗

Glycopeptides from murine teratocarcinoma cells: structure of the determinants recognised by Griffonia simplicifolia agglutinin I and by sera from patients with ovarian germ cell tumors.

High-molecular-weight glycopeptides synthesised by teratocarcinoma OTT6050 bear the binding site for Griffonia simplicifolia agglutinin I and are recognised by antibodies in the sera of patients with ovarian germ cell tumors. Digestion of the glycopeptides with endo-beta-D-galactosidase C abolished the lectin binding activity and the antigenic activity. Since the product of the enzymic digestion is alpha-D-Gal-(1----3)-D-Gal, it is concluded that the disaccharide structure is involved in the lectin binding site and the antigenic site.

Animals↗

Poly-N-acetyllactosamines synthesized by cultured Ehrlich carcinoma cells: application of endo-beta-galactosidase C for analysis of the terminal structure.

Poly-N-acetyllactosamines were prepared from Ehrlich carcinoma cells cultured in the presence of [14C]galactose. Methylation analysis indicated that 31% of the galactose was in the non-reducing end. Of it, 77% was cleaved by alpha-galactosidase, and 56% was released as a disaccharide by endo-beta-galactosidase C. Methylation analysis confirmed that the released disaccharide was mostly Gal alpha 1----3Gal. Therefore, Gal alpha 1----3Gal structure, not Gal alpha 1----3(Gal alpha 1----6)Gal structure, was the major alpha-galactosyl structure in the poly-N-acetyllactosamines synthesized. Furthermore, alpha-galactosidase digestion did not change the content of disubstituted galactosyl residues. Thus, Gal alpha 1----3(Gal alpha 1----6)Gal structure, which was suggested to be the sole non-reducing terminal structure of poly-N-acetyllactosamines of Ehrlich carcinoma cells, was not detected in significant amounts under the present experimental conditions.

Animals↗

Receptors for fucose-binding proteins of Lotus tetragonolobus isolated from mouse embryonal carcinoma cells. Structural characteristics of the poly(N-acetyllactosamine)-type glycan.

Receptors for fucose-binding proteins of Lotus tetragonolobus were isolated from N4-1 and F9 embryonal carcinoma cells. They were glycoproteins, whose major components had apparent relative molecular masses of more than 100,000. Carbohydrates released from the receptors of N4-1 cells by hydrazinolysis were separated into three fractions by gel filtration. Binding activity to the lectin was detected in the high-molecular-mass fraction. The composition of the large glycan was characteristic of the poly (N-acetyllactosamine)-type, and glucosamine was identified as the sugar involved in the protein-carbohydrate linkage. The glycan has one fucosyl residue per four N-acetyllactosamine units. Most of the fucose was linked to the C-3 hydroxyl group of N-acetylglucosamine. No Fuc alpha 1----2Gal or Fuc alpha 1----4GlcNAc linkage was detected. The glycan had a relative molecular mass of 9000 or more and the poly(N-acetyllactosamine) units were branched. N-Acetylgalactosamine residues were detected in non-reducing ends of at least a part of the glycan. Therefore, the glycan has a more complex structure than the related one from human granulocytes, although both of them have Fuc alpha 1----3GlcNAc termini.

Animals↗

Purification and properties of N-acetylglucosaminide alpha 1----3-fucosyltransferase from embryonal carcinoma cells.

A membrane-bound alpha-L-fucosyltransferase, which is involved in the synthesis of a developmentally regulated carbohydrate antigen, SSEA-1, was purified about 2000-fold from F9 embryonal carcinoma cells. The procedures used were solubilization with Triton X-100, column chromatography on SP-Sephadex, DEAE-Sephadex, RCA-agarose and on GDP-agarose. Upon sodium dodecyl sulfate gel electrophoresis, the purified preparation gave a protein band with a relative molecular mass of 65 000. The optimum pH of the enzyme was between 6.0 and 7.0 and the Km toward N-acetyllactosamine was 0.55 mM. The enzyme was active with asialofetuin, but not with intact fetuin. Susceptibility of the product to alpha-L-fucosidase I from almond emulsin verified that the enzyme transferred fucose to C-3 hydroxyl of N-acetylglucosamine in the N-acetyllactosamine structure. Activities of beta-galactoside alpha 1----2-fucosyltransferase and N-acetylglucosaminide alpha 1----4-fucosyltransferase acting on synthetic substrates were not detected in the purified enzyme nor in the crude extract of F9 cells. PYS-2 parietal endoderm cells lacked all the fucosyltransferases mentioned above.

Amino Sugars↗

Liquid chromatographic determination of uric acid and ascorbic acid in rat retinae after ophthalmic artery and optic nerve ligation.

Change of urate and ascorbate levels in retinae of rat left eyes after ophthalmic artery and optic nerve ligation was studied by reversed-phase high-performance liquid chromatography with electrochemical detection. The right eyes were used for sham operation. We found that uric acid levels in the retinae of the left eyes increased as a function of time after the operation, whereas those of the right eyes remained unchanged. In addition, we found that ascorbic acid levels in the retinae of the rat eyes decreased after the operation.

Animals↗