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Biomedical subjects

N Baba

Publications and source records attributed to N Baba.

At least 19 recordsLinked to original sources
PubMed1996

Phospholipase A(2) activity in non-glycated and glycated low density lipoproteins.

The oxidation of low density lipoprotein (LDL) is believed to be an important risk factor for atherosclerosis. We have previously reported that glycation of LDL enhances LDL oxidation. Incubation of LDL in the presence of 200 mM glucose resulted in the enhanced formation of phosphatidylcholine hydroperoxide (PC-OOH) and cholesteryl ester hydroperoxide (CE-OOH). Fe(3+)-ADP accelerated the formation of hydroperoxides. The concentration of PC-OOH was much smaller than that of CE-OOH. In addition, we found a PC-OOH decomposing activity in LDL by following linoleic acid hydroperoxide (18:2-OOH) formation from 1-stearoyl-2-[13'-(S)-hydroperoxy-9', 11'-octadecadienoyl]-sn-glycero-3-phosphocholine (SLPC-OOH). Hydrolysis was similar between LDL and glycated LDL. Pretreatment by para-bromophenacylbromide, histidine modifier and phospholipase A(2) inhibitor, retarded the formation of 18:2-OOH only by 30%. The addition of equimolar platelet activating factor (PAF) reduced hydrolysis by 50%, indicating PAF acetylhydrolase may be responsible for the hydrolysis of PC-OOH.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1996

Geometry of the flagellar motor in the cytoplasmic membrane of Salmonella typhimurium as determined by stereo-photogrammetry of quick-freeze deep-etch replica images.

The precise geometry of the flagellar basal structure anchored in the cytoplasmic membrane was determined by digital stereo-photogrammetry of the images captured by quick-freeze deep-etch replica electron microscopy. In order to examine the structure on the periplasmic side of the membrane, we analyzed the MS ring complexes of Salmonella typhimurium overproduced in the cytoplasmic membrane of Escherichia coli. The rod, the S ring, and the shoulder of the M ring were exposed to the periplasm. On the cytoplasmic side of the membrane, small bumps corresponding to the cytoplasmic rod were discernible. We also examined the intact inner surface of the cells of polyhook mutant which was prepared by a new protocol and found the bell-shaped structure extending from the membrane towards the cytoplasm. It was identified as the C ring, since it was located at the base of the polyhook. Various dimensions of the MS ring complex and the C ring projecting from the membrane were determined by digital stereo-photogrammetry, and a three-dimensional model of the total basal structure is presented.

Cell Membrane↗
PubMed1995

Low expression of adhesion molecules in a case of cutaneous T-cell lymphoma.

A case of cutaneous T-cell lymphoma (CTCL) with low expression of the adhesion molecules lymphocyte function-associated antigen-1 (LFA-1), intercellular adhesion molecule-1 (ICAM-1), and very late antigen-4 (VLA-4) is described. The patient was a 90-year-old man with red round homogeneous tumors on his scalp, trunk, and extremities. He had no history of definite erythema or plaque stage. A biopsy sample taken from a tumor revealed massive infiltration of atypical lymphocytes in the reticular dermis and subcutis with a definite clear zone. The atypical lymphocytes were medium-sized with slightly convoluted nuclei. Immunohistochemically, the infiltrates showed the phenotype of so-called memory T cells. On the basis of these features, the case was diagnosed as CTCL. Expression of LFA-1, ICAM-1 and VLA-4 on the infiltrates was 9%, 13% and 11%, respectively, which is much lower than that in classic mycosis fungoides. This finding suggests that loss of these adhesion molecules may contribute to loss of epidermotropism in the advanced stage of CTCL.

Aged↗
PubMed1995

Inhibitory effect of FUT-175 on the production of interleukin 8 and polymorphonuclear leukocyte elastase.

We investigated the inhibitory effects of a protease inhibitor, FUT-175, on the production of interleukin 8 (IL-8) and polymorphonuclear leukocyte elastase (PMNE) by polymorphonuclear leukocytes (PMN) and vascular endothelial cells. IL-8 production by PMN and vascular endothelial cells stimulated with lipopolysaccharide (LPS) was inhibited by FUT-175. This compound also inhibited PMNE production by PMN following LPS stimulation.

Benzamidines↗
PubMed1994

Typical fibrolamellar hepatocellular carcinoma in Japanese patients: report of two cases.

We report herein the cases of two Japanese patients with typical fibrolamellar hepatocellular carcinoma treated at our institute. The first patient was a 19-year-old man with no hepatitis B or C viral infection and a normal, noncirrhotic liver in the nontumorous area. The second was a 36-year-old woman with no viral infection and a noncirrhotic liver in the nontumorous area. The clinicopathology, imaging appearances, and histology of both cases were similar to reports from the United States.

Adult↗
PubMed1994

Phospholipid hydroperoxides are significantly less toxic to cultured endothelial cells than fatty acid hydroperoxides.

Optically active hydroperoxides of phospholipids including phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidic acid were synthesized, and their cytotoxicity to cultured bovine pulmonary artery endothelial cells was examined. Phospholipid hydroperoxides were readily incorporated into cells during the incubation in a medium containing each hydroperoxide. Phospholipids with a linoleic acid hydroperoxide residue showed no toxicity, whereas phosphatidylcholine with an arachidonic acid hydroperoxide residue was somewhat toxic. When hydroperoxyarachidonoylphosphatidylcholine was reduced to hydroxyarachidonoylphosphatidylcholine, the reduction product was found to have no toxicity. It appears that phospholipid hydroperoxides, unless converted into more reactive compounds, are significantly less toxic to endothelial cells than fatty acid hydroperoxides.

Animals↗
PubMed1994

Ultrastructural analysis of the autophagic process in yeast: detection of autophagosomes and their characterization.

Under nutrient-deficient conditions, the yeast S. cerevisiae sequesters its own cytoplasmic components into vacuoles in the form of "autophagic bodies" (Takeshige, K., M. Baba, S. Tsuboi, T. Noda, and Y. Ohsumi. 1992. J. Cell Biol. 119:301-311). Immunoelectron microscopy showed that two cytosolic marker enzymes, alcohol dehydrogenase and phosphoglycerate kinase, are present in the autophagic bodies at the same densities as in the cytosol, but are not present in vacuolar sap, suggesting that cytosolic enzymes are also taken up into the autophagic bodies. To understand this process, we performed morphological analyses by transmission and immunological electron microscopies using a freeze-substitution fixation method. Spherical structures completely enclosed in a double membrane were found near the vacuoles of protease-deficient mutant cells when the cells were shifted to nutrient-starvation media. Their size, membrane thickness, and contents of double membrane-structures corresponded well with those of autophagic bodies. Sometimes these double membrane structures were found to be in contact with the vacuolar membrane. Furthermore their outer membrane was occasionally seen to be continuous with the vacuolar membrane. Histochemical staining of carbohydrate strongly suggested that the structures with double membranes fused with the vacuoles. These results indicated that these structures are precursors of autophagic bodies, "autophagosomes" in yeast. All the data obtained suggested that the autophagic process in yeast is essentially similar to that of the lysosomal system in mammalian cells.

Alcohol Dehydrogenase↗
PubMed1994

Relationship between leukotriene B4 and prostaglandin I2 in patients with sepsis.

To examine the roles of leukotriene B4 (LTB4) and prostaglandin I2 (PGI2), the metabolites of arachidonic acid found in patients with sepsis, we measured the serum levels of LTB4 and a stable metabolite of PGI2, 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), in 22 patients with sepsis. Results were analyzed in relation to patients' survival. The serum levels of both LTB4 and 6-keto-PGF1 alpha were significantly higher in patients who died than in those who survived, thus serving as indicators of illness severity. There was a significant correlation between LTB4 and 6-keto-PGF1 alpha levels. The present study suggests that LTB4, a potent leukocyte activator, induces damage to vascular endothelial cells in patients with sepsis, resulting in the excessive production of PGI2 and, consequently, serious illness.

6-Ketoprostaglandin F1 alpha↗
PubMed1994

Blood cytokine and complement levels in patients with sepsis.

We measured serum levels of endotoxin, cytokines, and eicosanoids and investigated their relationship to serum complement levels in patients with sepsis. Serum endotoxin (Et) levels (5.3 +/- 2.4 pg/ml) were within the normal range, but levels of tumor necrosis factor-alpha (TNF-alpha, 114 +/- 104.94 pg/ml), interleukin 6 (IL-6, 86.7 +/- 50.9 pg/ml), interleukin 8 (IL-8, 86.8 +/- 49.7 pg/ml), type-II phospholipase A2 (type II PLA2, 211.3 +/- 193.9 ng/ml), leukotriene B4 (LTB4, 88.7 +/- 27.2 pg/ml), thromboxane B2 (TXB2, 58.7 +/- 50.9 pg/ml) and 6-keto-prostaglandin F1 alpha (PGF1 alpha, 21.0 +/- 11.0 pg/ml) levels were above normal. Levels of C3a (1088.4 +/- 83.8.7 ng/ml) and C4a (1951.5 +/- 1697.8 ng/ml) were also above normal; C3 (66.0 +/- 25.6 mg/dl) and C4 (23.6 +/- 5.3 mg/dl) were within the normal range, and C5a was lower than the detectable limit in all but one of the subjects. Serum TNF-alpha was significantly correlated with C3a (p < 0.001). Serum IL-6 had a significant negative correlation with C3 (p = 0.002) and C4 (p = 0.010). Type II PLA2 was significantly correlated with C3a (p < 0.001). There were no significant correlations between serum Et or IL-8 and serum C3, C4, C3a or C4a. Our findings suggest that increased levels of TNF-alpha, IL-6, and Type II PLA/ in patients with sepsis contribute to activation of the complement system.

Adult↗
PubMed1994

[A case of polyarteritis nodosa who developed rapidly progressive glomerulonephritis and presented with a tumor-like shadow on head CT in the remission stage].

A 70-year-old woman was admitted to our hospital because of weight loss, fever of unknown origin and rapid deterioration of renal function. Polyarteritis nodosa was diagnosed based on the findings of fever, weight loss, thrombocytosis, arthralgia and crescentic glomerulonephritis with vasculitis in the kidney biopsy specimens. Renal function progressively deteriorated and the patient underwent peritoneal dialysis (PD). Methylprednisolone pulse therapy and subsequent oral prednisolone (PSL) therapy combined with cyclophosphamide (CY) was instituted. Renal function gradually recovered and PD was discontinued 2 weeks later. She was discharged after about 2 months of hospitalization and received a monthly follow-up with daily administration of 10mg of PSL and 25mg of CY. Six months after discharge, PN activity was well controlled by PSL and CY, but mental disturbance gradually developed and head CT disclosed a low-density mass shadow that was enhanced with a ring-like appearance by contrast medium similar to a brain tumor. The follow-up CT did not show any enlargement of the mass shadow. One year later, the patient died of uremia and concomitant dementia. Autopsy disclosed cerebral infarct in the relevant site of the mass on CT and the healed stage of angitis in other tissues.

Acute Disease↗
PubMed1994

Comparative study of cutaneous T-cell lymphoma and adult T-cell leukemia/lymphoma.

An important disease entity distinct from cutaneous T-cell lymphoma (CTCL) in Japan is adult T-cell leukemia/lymphoma (ATL), which shows almost the same phenotype as CTCL, ie, a helper/inducer T-cell phenotype (CD4-positive, CD8-negative), and usually involves the skin. This article describes differences between CTCL and ATL in terms of clinical and immunopathologic cell surface features. In patients with ATL, the predominant physical findings were lymph node, bone marrow and skin involvement, hepatosplenomegaly, leukemic manifestations, and an aggressive course. In patients with CTCL, in contrast, only skin lesions predominated at the onset of the disease and a relatively good prognosis was shown. The predominant phenotype of the neoplastic cells in the skin of patients with CTCL was CD3+, CD4+, CD29+, CD45RO+, HLA-DR+, HLA-DQ+, CD7-, L-selectin-, and CD45RA-. Some phenotypic discrepancy was found between the neoplastic cells in the peripheral blood, lymph nodes and skin of patients with ATL with respect to CD45RA and CD45RO, and CD7, CD29, CD25, and HLA-DR. That is, the predominant neoplastic cell phenotype was helper T-cell, which was CD3+, CD4+, L-selectin+, CD25+, CD45RA+, HLA-DR+, CD29-, and CD45RO- in peripheral blood, and CD3+, CD4+, L-selectin+, CD29+, CD45RO+, HLA-DR+, and CD45RA- in the skin and lymph nodes. Phenotypic heterogeneity of ATL cells and heterogeneity of CD45R isoform expression on ATL cells were evident in different organs. These findings confirm that the difference in antigen expression on the cell surface might reflect the clinical features of ATL and CTCL. CTCL cells do not share the same phenotype as ATL cells.

Adult↗
PubMed1994

[A case of membranoproliferative glomerulonephritis due to type II cryoglobulinemia probably associated with hepatitis C virus infection].

In recent years, several laboratories have suggested that chronic hepatitis C virus (HCV) infection is strongly associated with type II cryoglobulinemia (CG) and/or membranoproliferative glomerulonephritis (MPGN). We report here a case of MPGN due to type II CG probably associated with chronic HCV infection, and discuss the pathogenesis and treatment of such cases. A 60-year-old-female was referred to us from a local hospital because of progressive peripheral edema, purpura on the lower limbs, pleural effusion, ascites, hypertension, and renal failure. Laboratory findings indicated proteinuria, abnormal urinary sediments, normochromic normocytic anemia and azotemia. Other laboratory findings included positive rheumatoid factor, elevated serum IgM, hypocomplementemia and elevated circulating immune complexes. Cryoglobulin was detected and found to consist of a mixture of a monoclonal IgM kappa with polyclonal IgG. Renal biopsy showed MPGN. These observations suggested a close association between MPGN and type II CG. We did not find any causes of type II CG except for positive HCV antibody and HCV RNA. Therefore, we made the diagnosis of type II CG associated with chronic HCV infection. Symptoms related to CG was responsiveness to steroid, but development of liver dysfunction developed. Treatment with alfa-interferon (alpha IFN) was added and thereafter, the liver dysfunction improved. However, the serum Cryo level was not reproducibly lowered. While in this case it was unclear whether IFN therapy was beneficial, several reports in addition to the findings of this case suggest a close relation between HCV infection and type II CG and MPGN.(ABSTRACT TRUNCATED AT 250 WORDS)

Cryoglobulinemia↗
PubMed1993

Inhibitory effects of a cholecystokinin antagonist, loxiglumide (CR-1505), on the growth of freshly separated and xenografted human pancreatic cancer.

The effects of cholecystokinin (CCK) and a CCK antagonist, loxiglumide (CR-1505), on four freshly separated and six xenografted human pancreatic cancers, were investigated. The level of DNA synthesis in only one of five tested pancreatic cancers was enhanced by CCK at concentrations of 0.01-10 nM, while in the other four cancers DNA synthesis was not affected. The levels of DNA, RNA, and protein synthesis (by 3H-thymidine, 3H-uridine, and 3H-leucine incorporation tests, respectively) in all the tested cancers were dose-dependently inhibited by loxiglumide at concentrations of 20-2000 microM, and the IC50 of loxiglumide for DNA synthesis in pancreatic cancers was 156 +/- 80 microM (means +/- SD). The in vivo effect of loxiglumide was assessed using a xenografted line (PC-HN) transplanted in nude mice. The in vivo 50% lethal dose of loxiglumide for nude mice was about 500 mg/kg. Death was caused by respiratory failure due to severe congestion of the lung after the administration of a large dose of loxiglumide. The growth of a PC-HN transplanted in the nude mice was significantly inhibited by subcutaneous loxiglumide at 250 mg/kg, twice a day for 28 days, which did not cause death. It is suggested that loxiglumide inhibits the in vivo and in vitro growth of human pancreatic cancer, perhaps independently of its action as a CCK antagonist, and this study also suggests that loxiglumide may be a new type of therapeutic agent to be used for the treatment of human pancreatic cancer.

Animals↗
PubMed1993

Effects of hypercholesterolemia on initial and chronic phases of rat nephrotoxic serum nephritis: development of focal segmental glomerulosclerosis, analogous to atherosclerosis.

The effects of hypercholesterolemia on both the initial and chronic phases of rat nephrotoxic serum (NTS) nephritis have been investigated. Injury during the initial phase of NTS nephritis in hypercholesterolemic rats maintained on a cholesterol-supplemented diet (Group 2) was characterized by segmentally accentuated accumulations of vacuolated cells with lipid droplets (foam cells) in the glomeruli, while the kidneys of rats fed a standard diet (Group 1) revealed only mild intracapillary cell proliferation. Immunoelectron microscopy showed that the foam cells observed in Group 2 rats were largely derived from macrophages. The glomerular macrophage number, defined by the number of ED1-positive cells per glomerulus, was significantly higher in Group 2 than in Group 1 animals at days 5-6 (3.4 +/- 1.4 in Group 1 against 6.3 +/- 1.0 in Group 2; p < 0.01) as well as at days 21-28 (5.5 +/- 2.6 in Group 1 against 10.9 +/- 2.8 in Group 2; p < 0.01). In contrast, the numbers of OX19-positive T-lymphocytes and OX33-positive B-lymphocytes were similar in both groups. In the chronic phase of NTS nephritis at week 20, semiquantitative evaluation of the glomerular lesions disclosed more severe focal segmental glomerulosclerosis (FSGS) in Group 2 compared with Group 1 animals (glomerular injury score: 14 +/- 10 in Group 1 against 73 +/- 17 in Group 2; p < 0.01). Accumulations of lipid and foam cells were invariably seen in the sclerotic foci of Group 2 animals. The results indicate that hypercholesterolemia played an important role in the accelerated development of FSGS in rat NTS nephritis.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1993

Evidence for 5-HT2 receptor involvement in the stimulation of preovulatory LH and prolactin release and ovulation in normal cycling rats.

The participation of serotonin (5-HT) in the control of LH secretion and ovulation has been reported in numerous pharmacological experiments, although the results have been contradictory. In this study to determine the physiological involvement of 5-HT2 receptors in the control of preovulatory LH and prolactin (PRL) release and ovulation, ketanserin (KET), a selective 5-HT2 receptor antagonist, was administered to normal cycling rats. Oral administration of KET at 10 mg/kg BW between 0900h and 1300h on the day of proestrus completely blocked ovulation, while the administration after 1500h did not. The ovulation was confirmed 2 days after treatment with KET. There was no consistent effect on the number of ova ovulated. Co-administration of KET with 5-methoxy-N,N-dimethyltryptamine (5-MeDMT), a 5-HT agonist, at a dose of 2 mg/kg BW ip reversed KET-induced inhibition of ovulation. The highest rate (89%) of reversal was obtained by co-administration at 1500h. KET administered at 1100h completely blocked the preovulatory surge of LH and PRL observed in control animals at 1800h. The present study suggests that 5-HT stimulates preovulatory LH and PRL surge and ovulation via 5-HT2 receptor under physiological conditions and that the effect of 5-HT depends on the critical period and the 24-hour periodicity.

Animals↗