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Biomedical subjects

Y Mikami

Publications and source records attributed to Y Mikami.

At least 217 records · Page 12Linked to original sources
PubMed1993

A tumor cell line producing granulocyte colony-stimulating factor and an immune suppressive factor.

From a patient, both a cell line incapable of secreting granulocyte colony-stimulating factor (G-CSF) (TC873) and a cell line capable of secreting G-CSF (TCM902) were established. The effector cells induced, with TC873 cells showed a high lytic capacity against two types of tumor cells. The effector cells induced by TCM902 cells did not show such capacity. Furthermore, the TCM902 cells excreted a factor suppressing the proliferation of lymphokine activated killer (LAK) cells and the autologous tumor cell lysis of tumor associated lymphocytes. This factor probably is TFG-beta 1.

Cell-Free System↗
PubMed1993

Age, sex and source of hamster affect experimental cholesterol cholelithiasis.

In the present study, we examined the effect of the following factors on a hamster model of cholesterol cholelithiasis: (i) the source of the golden Syrian hamsters (Sasco, Omaha, NE or Charles River, Wilmington, MA), (ii) the sex of the experimental animals and (iii) their age (4 wk vs. 8 wk of age). All hamsters were fed a semipurified diet which contained cholesterol (0.3%) and palmitic acid (1.2%). No cholesterol gallstones formed in any of the female hamsters regardless of age or source. The 4-week-old male hamsters from Sasco had the greatest incidence of gallstones (93%). The 8-week-old male hamsters tended to have a lower incidence of cholesterol gallstones than the younger ones, regardless of the commercial supplier (67 vs. 93% for Sasco and 27 vs. 40% for Charles River). Female hamsters had higher liver and serum cholesterol levels than the male hamsters; Charles River hamsters had lower serum cholesterol concentrations than the Sasco animals. Total biliary lipid concentrations were highest in Sasco male hamsters, but biliary cholesterol (mol%) was lower in the males than in the females (4.2-4.5% vs. 6.1-7.1%) regardless of age. The cholesterol saturation indices were higher in the Sasco females than the corresponding males; these values were lower in the Sasco hamsters than the Charles River animals, regardless of age or sex. The male Sasco hamsters had a higher total biliary bile acid concentration (98.9 mg/mL) than the Sasco females (58.9 mg/mL) and the Charles River animals (24.6 mg/mL for males and 38.2 mg/mL for females). The percentage of chenodeoxycholic acid in bile was significantly lower, and the percentage of cholic acid was higher in all females as compared to males.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1993

Simultaneous and separated culture of keratinocytes and fibroblasts on each side of a collagen membrane.

We have developed a new cell culture system which is of benefit for the research of dermal-epidermal interaction. In this system, normal human keratinocytes are cultured on the upper surface of a permeable collagen membrane, on the undersurface of which human fibroblasts are simultaneously and separately cultured in a lifted condition. Both the keratinocytes and fibroblasts showed good proliferation and differentiation which were revealed by phase contrast microscopy as well as light and electron microscopies. A permeability test of the collagen membrane used in the present study showed that peptides of less than 30 kDa are able to penetrate through the membrane. Using this system, we estimated the total protein content and cornified envelope formation in the keratinocytes cultured with or without fibroblasts. We found that the total protein and cornified envelope formation were significantly increased when keratinocytes were cultured together with fibroblasts. When keratinocytes were cultured with fibroblasts in the condition of air-liquid interface, synthesis of the cornified envelope was further enhanced. These results indicate that fibroblasts really effect not only the proliferation but also the differentiation of keratinocytes, and the air-liquid interface enhances their effect on differentiation. This bi-phase separated cell culture system is a useful tool for the study of keratinocyte-fibroblast interaction.

Cells, Cultured↗
PubMed1993

Inactivation of rifampin by Nocardia brasiliensis.

Rifampin was glycosylated by a pathogenic species of Nocardia, i.e., Nocardia brasiliensis. The structures of two glycosylated compounds (RIP-1 and RIP-2) isolated from the culture broth of the bacterium were determined to be 3-formyl-23-(O-[beta-D-glucopyranosyl])rifamycin SV and 23-(O-[beta-D-glucopyranosyl])rifampin, respectively. Both compounds lacked antimicrobial activity against other gram-positive bacteria as well as the Nocardia species.

Glycosylation↗
PubMed1993

[Angiogenesis in head and neck tumor].

To clarify the correlation between tumor angiogenesis and tumor growth in head and neck carcinomas, we investigated the number of microvessels, using immunohistochemical factor VIII. No correlations among this number, differences in the primary lesion, histological differentiation and T classification were detected. The incidence of neck lymph node metastases increased as microvessel numbers increased in tumor sites. The number of microvessels increased as N and Stage classification progressed. The number of microvessels in CR cases after induction chemotherapy were increased. The numbers of microvessels in patients without recurrence were apparently greater than those in patients with recurrence. The results of this study suggest that the number of microvessels in a primary tumor correlates with the metastatic ability of the tumor.

Adult↗
PubMed1993

[The expression of ICAM-1 on head and neck squamous cell carcinoma cell lines].

Intercellular adhesion molecule-1 (ICAM-1) is one of the cell adhesion molecules. This molecule is a glycoprotein of about 90 KDa belonging to the immunoglobulin (Ig) superfamily and is widely expressed by hematopoietic and non-hematopoietic cells which play a role in the immune system. ICAM-1 is also a ligand or counter-receptor for the leukocyte integrin lymphocyte-function associated antigen-1 (LFA-1). We investigated the expression of ICAM-1 on the surfaces of cells from fifteen head and neck squamous carcinoma cell lines and the modulation of ICAM-1 expression by IFN-gamma, using an immunohistochemical stain. We categorized four types of stain degree. (-): < 10% of cells positive (+/-): 10-40% of cells positive (+): < 40-70% of cells positive (++): > 70% of cells positive Four cell lines showed (-) type. Three cell lines: (+/-). One cell line: (+). Seven cell lines: (++). The primary site of cell lines and the degree of ICAM-1 expression were not detectable. Connection between pathological differentiation and the degreed expression were not apparent, either. IFN-gamma up-regulated the degree of ICAM-1. All cell lines, when stimulated by IFN-gamma, showed (++) type.

Carcinoma, Squamous Cell↗
PubMed1993

Inactivated products of rifampicin by pathogenic Nocardia spp.: structures of glycosylated and phosphorylated metabolites of rifampicin and 3-formylrifamycin SV.

Rifampicin (1) was converted into four inactivated products by pathogenic Nocardia, RIP-1 and RIP-2 by N. brasiliensis and RIP-3 and RIP-4 by N. otitidiscaviarum. MS and NMR analysis showed the compounds to be 3-formyl-23-[O-(beta-D-glucopyranosyl)]rifamycin SV (2), 23-[O-(beta-D-glucopyranosyl)]rifampicin (3), 21-(O-phosphoryl)rifampicin (4) and 3-formyl-21-(O-phosphoryl)-rifamycin SV (5), respectively.

Drug Resistance↗
PubMed1993

[Pulmonary hypertension in autopsy cases of mixed connective tissue disease].

We histologically studied pulmonary vascular lesions of 11 MCTD autopsy cases without clinical manifestation of pulmonary hypertension (PH), and compared them with 6 advanced PH cases. Pulmonary vascular changes such as cellular intimal proliferation, intimal fibrosis, and fresh and/or organized thrombi characterized by PH were also found in non-PH cases. Furthermore, there was severe obstructive vasculopathy in small vessels of less than 100 microns in diameter, though they were not frequently observed in non-PH cases. These results suggest that morphological changes of pulmonary vessels in non-PH are qualitatively similar to those of PH. The important point between PH and non-PH cases in MCTD is whether the pulmonary arterioles over 200 microns in diameter are diffusely involved or not. The endothelial damage in the early stage, followed by microthrombi and proliferation of intimal myocytes seems to progress to severe pulmonary vascular diseases with PH.

Adult↗
PubMed1993

Decrease of plasma large, light LDL (LDL1), HDL2 and HDL3 levels with concomitant increase of cholesteryl ester transfer protein (CETP) activity by probucol in type II hyperlipoproteinemia.

The effects of 12 week probucol treatment on plasma lipoprotein subfraction levels and on lecithin: cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) activities in type II hyperlipoproteinemia were investigated. Plasma VLDL-TG, VLDL-apoB, VLDL-apoCII and VLDL-apoCIII concentrations were not changed by probucol, but VLDL-TC and VLDL-PL levels were slightly reduced. Probucol slightly reduced plasma IDL-TC, but not IDL-TG, IDL-PL and IDL-apoB levels. Plasma large, light LDL (LDL1)-TC, LDL1-PL, LDL1-apoB levels were decreased significantly by 28.5 +/- 20.1% (p < 0.001), 18.1 +/- 18.8% (p < 0.01) and 23.3 +/- 19.1% (p < 0.001) by probucol treatment while LDL1-TG concentration was unchanged. Absolute amounts of plasma small, heavy LDL(LDL2)-TC, LDL2-TG, LDL2-PL and LDL2-apoB levels remained unchanged but percent increases of LDL2-TC and LDL2-apoB were statistically significant (p < 0.05). 2-16% gradient polyacrylamide gel electrophoresis demonstrated the diminution of LDL of large size by probucol treatment. Probucol markedly reduced plasma high density lipoprotein levels. The reductions of HDL2-TC, HDL2-TG, HDL2-PL and HDL2-apoAI concentrations were 36.2 +/- 25.4% (p < 0.001), 25.8 +/- 36.9% (p < 0.01), 34.4 +/- 23.8% (p < 0.001) and 35.6 +/- 28.4% (p < 0.001). Probucol significantly decreased plasma HDL3-TC, HDL3-PL and HDL3-apoAI amounts by 17.4 +/- 22.9% (p < 0.01), 18.3 +/- 20.8% (p < 0.01) and 19.8 +/- 27.9% (p < 0.01) without change of HDL3-TG level. The decrease of HDL2 level was more marked than that of HDL3 level. Probucol did not change LCAT activities. Probucol significantly stimulated CETP activities from 126.6 +/- 50.6 units to 172.8 +/- 40.2 units by 12 week treatment (p < 0.001). We concluded that probucol decreased plasma LDL1, HDL2 and HDL3 amounts and made them triglyceride-rich with the concomitant increase of CETP activities.

Carrier Proteins↗
PubMed1992

Uneven distribution of intracellular Cl- in rat hippocampal neurons.

Electrophysiological observations of neurons suggest that perikarya and dendrites differ in local intracellular Cl- concentration ([Cl-]i), that has not been demonstrated yet. Regional [Cl-]i in cultured hippocampal neurons was estimated using a Cl(-)-sensitive fluorescent dye. Calibration showed that perikaryonic [Cl-]i was lower than dendritic [Cl-]i. Ethacrynic acid, an inhibitor of the outwardly directed Cl(-)-pump, increased the perikaryonic but not dendritic [Cl-]i. A decrease in [Cl-]i induced by furosemide or bumetanide, inhibitors of Na+/K+/2Cl- cotransporters, was more prominent in dendrites than in perikarya. These findings suggest that uneven distribution of Cl- is generated by the region-specific localization of these transporters.

Animals↗
PubMed1992

Carboxyl-terminal deletion and point mutations decrease the transforming potential of the activated rat neu oncogene product.

The rat neu oncogene encodes a constitutively activated growth factor receptor/transmembrane tyrosine kinase, p185Tneu, that is structurally similar to yet distinct from the epidermal growth factor receptor. To explore the role of the carboxyl-terminal region and of putative autophosphorylation sites in regulating the activity of the rat p185Tneu (T, transforming) protein, we used site-directed mutagenesis to generate a p185Tneu mutant in which a putative tyrosine autophosphorylation site (residue 1253) at the extreme carboxyl terminus was replaced by a phenylalanine residue and a mutant in which the carboxyl-terminal 122 amino acids were deleted. These proteins were expressed in NIH 3T3 cells at comparable levels and exhibited similar autophosphorylation activity, exogenous substrate phosphorylation ability, oligomerization levels, and responsiveness to a partially purified neu-activating factor. However, the mutant p185Tneu proteins displayed a decreased transforming capacity both in vitro and in vivo. This analysis demonstrated that the carboxyl-terminal domain and at least one putative tyrosine autophosphorylation site of p185Tneu play a role in positively regulating the cell growth-regulating properties of the neu protein.

3T3 Cells↗
PubMed1992

Comparative studies on the postantifungal effect produced by the synergistic interaction of flucytosine and amphotericin B on Candida albicans.

A turbidometric method was used to measure Candida albicans yeast cell growth and to quantitate the postantifungal effect (PAFE) after exposure to various concentrations of flucytosine and amphotericin B, alone and in combination, for 2 hr at 30 degrees C. The drug concentrations used in the PAFE assays were determined by initial MIC and FIC (fractional inhibitory concentration) evaluations. The PAFE was calculated by the difference in time (hr) required for growth of the control and test cultures to reach the 0.5 absorbance level following removal of the drug by dilution. A synergistic PAFE was evidenced with combinations of the two drugs at concentrations below their individual MICs. Combinations of flucytosine (0.012 to 0.049 micrograms ml-1) and amphotericin B (0.195 to 0.39 micrograms ml-1) produced PAFEs ranging from 6.3 to 21.8 hr. These PAFEs persisted from 0.3 to 14.7 hr longer than those achieved when each of the two agents was assayed separately.

Amphotericin B↗
PubMed1992

Localized cutaneous nocardiosis in Japan. A new case.

We report a case of localized cutaneous nocardiosis due to Nocardia asteroides, appearing on the anterior surface of the right forearm of a 29-year-old woman. Examination of the skin revealed a firm subcutaneous nodule measuring 32 x 20 mm and accompanied with a small ulcer. The histology of the lesion showed granulomatous changes interspersed with large numbers of polymorphonuclear leukocytes. On Gram staining, a few bacillary bodies were found scattered through the lesion, but no grains were detected. The classification of the clinical types of cutaneous nocardiosis is discussed, and the Japanese literature on localized cutaneous nocardiosis is examined.

Adult↗
PubMed1992

Light and electron microscopic studies on experimental nocardia-toxicosis in mice.

An exotoxin (HS-6) produced by Nocardia otitidiscaviarum isolated from certain lesions of cutaneous nocardiosis of a male 82-year-old patient induced severe injuries in the pancreas, liver, stomach, small intestine, heart, thymus and kidney of male ICR mice. Mice given Nocardia-free preparation of HS-6 at a dose of 1 mg/kg of body weight developed several autophagic vacuoles in the pancreas and liver within 20 min after the i.p. injection. Thereafter, the autophagic vacuoles increased in number and size with time. About 24 hr after the administration of HS-6, the liver showed marked accumulation of fat droplets in the cytoplasm of the hepatocytes. Although they contained abundant autophagic vacuoles in the regions of RER, there were no lipomatoses in the acinar cells of the pancreas, those of the chief cells and smooth muscle cells of the stomach, Paneth cells, goblet cells, smooth muscle cells of the small intestine, and plasma cells in the digestive tract. Biochemical examinations revealed that HS-6 had no significant effect on the protein synthesis of reticulocytes. Inoculation of the Nocardia into the mouse peritoneal cavities caused marked granulomatoses in the pancreas, liver and regional lymph nodes, but did not develop autophagic vacuoles in RER regions of these organs.

Aged↗
PubMed1992

Synergistic postantifungal effect of flucytosine and fluconazole on Candida albicans.

The in vitro efficacy of flucytosine and fluconazole, separately and in combination, with respect to induction of a postantifungal effect (PAFE) on Candida albicans was studied. PAFE refers to the persistent suppression of fungal cell growth following a short period of exposure to an antifungal agent. A turbidometric method was used to measure cell growth and to quantitate the PAFE following exposure of C. albicans yeast cells to different concentrations of the two agents for 2 h. The PAFE was determined by the difference in time (h) required for growth of the control and test cultures to increase to the 0.5 absorbance level following removal of the drug by dilution. Minimum (MIC) and fractional inhibitory concentration determinations were made and the data used for selecting the concentrations used in the PAFE evaluations. A synergistic interaction of the two drugs at concentrations well below their individual MICs was evidenced. Flucytosine:fluconazole ratios of 1:16-1:32 at concentrations ranging from 0.024-0.098 micrograms ml-1 and from 0.78-1.56 micrograms ml-1, with flucytosine and fluconazole, respectively, induced PAFEs which persisted for 2.5 h longer than those achieved when each of the two agents was assayed separately.

Candida albicans↗