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Biomedical subjects

H Sawada

Publications and source records attributed to H Sawada.

At least 307 records · Page 17Linked to original sources
PubMed1991

Changes in subgenome types of adenovirus type 4 isolated from patients with ocular disease between 1985 and 1989 in Sapporo, Japan.

A total of 122 adenovirus type 4 (Ad4) strains isolated from patients with epidemic keratoconjunctivitis at an eye clinic in Sapporo, Japan, from 1985 to 1989 were identified as Ad4a. By the use of HinfI and TaqI restriction endonucleases, these Ad4a strains were classified into 12 subgenome types. During this observation period, two epidemics of Ad4 infection relating to epidemic keratoconjunctivitis occurred. During the Ad4a epidemic in 1985, three subgenome types became predominant successively. However, except for one strain, the prevalent strains isolated during the epidemic of Ad4a in 1988 all belonged to a single subgenome type. In the years when an Ad4a epidemic was not observed, such Ad4a strains were new or previous subgenome types. The prevalent subgenome types tended to change within several years.

Adenoviruses, Human↗
PubMed1991

Use of ofloxacin in prevention and treatment of secondary infections in hematological malignancies.

We evaluated the effectiveness of ofloxacin (OFX) administered for prophylactic purposes during 77 episodes of neutropenia (less than 500/mm3) in 54 patients with hematological malignancies and to combat infection in 17 patients with both hematological malignancies and secondary infections. The prophylactic effect of OFX was demonstrated by the absence of febrile episodes in 73.3% of patients during the neutropenic phase. Of 16 patients who developed secondary infections, 13 showed good responses with other antibiotics. The overall efficacy rate of OFX in secondary infections was 64.7%. Although 4 patients developed elevated SGOT and SGPT levels and 1 showed an elevated BUN level, OFX was generally well tolerated.

Adolescent↗
PubMed1991

The alpha 1 chain of type VIII collagen is associated with many but not all microfibrils of elastic fiber system.

The antigen of monoclonal antibodies which had labeled the hexagonal lattice of Descemet's membrane in a specific manner was shown to be the alpha 1 chain of type VIII collagen by immunoblotting followed by amino acid sequence analysis. With this antibody, the localization of alpha 1 (VIII) in various tissues was studied by several immunocytochemical methods. Under light microscopy, the alpha 1 (VIII) was found in a fine fibrillar form in various capsular tissues such as capsules of the liver, kidneys, adrenals, lungs and so on. It was also present in dense connective tissues such as the Achilles tendon, and periodontal and perivertebral ligaments. When some dense connective tissues which had been negative to the label including the intima of aorta, perimysium and Glisson's sheath of the liver, were subjected to pepsin digestion, epitopes were revealed which showed a specific immunofluorescence pattern. In many locations the pattern of localization coincided with that of elastic fiber components, and full or partial colocalization with tropoelastin or costaining with resorcin-fuchsin staining was observed. In immunoelectron microscopy, the antigen (alpha 1 (VIII)) was localized on the surface of, but not inside, elastic fibers. However, some tissues which are rich in elastic fibers or microfibrils remained unlabeled. These included elastic fibers of the aortic media and ligamentum nuchae as well as ciliary zonules. Therefore it is suggested that alpha 1 (VIII) is a collagen associated with microfibrils of some elastic fiber systems, but is not an intrinsic component of either elastic fibers or of microfibrils.

Amino Acid Sequence↗
PubMed1991

Effective production of anti-tetanus toxoid and anti-HBsAg human monoclonal antibodies by serum-free culture of hybridomas.

Two hybridoma systems, mouse.human-human (m.h-h) heterohybridoma and human-human (h-h) hybridoma, have been established, and hybridomas secreting anti-tetanus toxoid and anti-HBsAg human monoclonal antibodies (MoAbs), both having a neutralizing activity have been obtained. Cell-line improvement was shown to be an efficient method for improving the productivity in a cell culture process. Two kinds of serum-free media, GFS (a serum substitute)-containing media and polyethylene glycol (PEG)-containing media, have been established to produce human MoAbs. m.h-h Heterohybridomas could be cultivated for a long period by perfusion culture in an agitation vessel, but h-h hybridomas could not. We found that h-h hybridomas show growth-associated antibody production kinetics and established two kinds of long-term cultivation systems: continuous perfusion culture and semi-continuous immobilized perfusion culture. We also scaled up batch culture and short-term perfusion culture to 200-L and 50-L fermentors, respectively. Processes for large-scale purification from the culture supernatants of both GFS- and PEG-containing serum-free media have also been developed.

Animals↗
PubMed1991

Effects of protein kinase A and calcium/phospholipid-dependent kinase modulators in the process of HL-60 cell differentiation: their opposite effects between HL-60 cell and K-562 cell differentiation.

We have previously shown that HL-60 cells treated with 1 alpha, 25-(OH)2D3 in magnesium-deficient medium are committed to differentiate but do not express differentiation-related phenotypes. In the present study, we demonstrated that Mg2+ deprivation blocked the process of differentiation before the induction of lysozyme mRNA and that the process of HL-60 cell differentiation could be divided into two steps, i.e., a commitment step and a phenotypic expression step. We studied the effects of protein kinase A (PKA) and calcium/phospholipid-dependent protein kinase (PKC) modulators at each step. The results indicated that agonists of PKA enhanced both steps but that N-(2-[methylamino]ethyl-5-isoquinolinesulfonamide inhibited them. On the other hand, 1-oleyl-2-acetylglycerol and 12-O-tetradecanoylphorbol-13-acetate enhanced the commitment step but inhibited that of phenotypic expression. Staurosporine and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine inhibited the commitment step and enhanced that of phenotypic expression. These results indicate that PKA acts as a positive regulatory signal and that PKC has a dual role in the process of HL-60 cell differentiation, i.e., as a positive regulatory signal in the commitment step and as a negative one in the phenotypic expression step. Recently, we have also shown that in K-562 cell differentiation into erythroid lineage, PKA may serve as a negative regulatory signal in both steps; however, PKC may act dually, namely as a negative regulatory signal in the commitment step and as a positive one in the phenotypic expression step.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaloids↗
PubMed1991

Tissue distribution of type VIII collagen in human adult and fetal eyes.

The type VIII collagen tissue distribution in human adult (32-78 yr of age) and fetal (16-27 weeks of gestation) eyes was studied immunohistochemically using a monoclonal antibody to type VIII collagen. Type VIII collagen was distributed in a linear or fibrous fashion in adult eyes in Descemet's membrane of the cornea, the trabecular meshwork, the walls of Schlemm's canal, Bruch's membrane, the choroidal stroma, the sclera, the cribriform plates of the optic nerve, and the intima of the central retinal artery. The staining in the central retinal artery was similar to that of type IV collagen. No distinct positive staining was seen in other blood vessels. When fetal eyes were examined, significant differences in positive staining were found between adults and fetuses in the sclera. In fetal eyes, the posterior sclera was strongly stained; however, the positive staining gradually decreased, and in the equatorial area it disappeared. The cribriform plates of the lamina cribrosa and the presumptive Bruch's membrane in fetal eyes did not react with the antibody. The trabecular meshwork and Descemet's membrane, but no other part of anterior section of fetal eyes, reacted with the antibody.

Adult↗
PubMed1991

[Clinical effect of miconazole gel against upper digestive tract mycosis].

A total of 43 patients, comprising 41 patients with oral candidiasis and 2 with esophageal candidiasis, were treated with miconazole (MCZ) gel to assess its efficacy and safety in treating upper digestive tract mycosis. The efficacy of the drug was evaluable in 33 of them, consisting of 32 patients with oral candidiasis and 1 with esophageal candidiasis. The clinical efficacy rate of the drug against oral candidiasis was 87.5% (28/32 patients), and the clinical response was good in the 1 evaluable patient with esophageal candidiasis. The safety of the drug was assessed in 40 patients. In 3 (7.5%) of them, nausea occurred as an adverse event, but was not particularly serious in any of them. No abnormal laboratory test values caused by the drug were observed. The results suggested that MCZ gel would be a very useful drug in treating oral and esophageal candidiasis.

Adolescent↗
PubMed1990

Demonstration of 3 alpha(17 beta)-hydroxysteroid dehydrogenase distinct from 3 alpha-hydroxysteroid dehydrogenase in hamster liver.

NAD(+)-linked and NADP(+)-linked 3 alpha-hydroxysteroid dehydrogenases were purified to homogeneity from hamster liver cytosol. The two monomeric enzymes, although having similar molecular masses of 38,000, differed from each other in pI values, activation energy and heat stability. The two proteins also gave different fragmentation patterns by gel electrophoresis after digestion with protease. The NADP(+)-linked enzyme catalysed the oxidoreduction of various 3 alpha-hydroxysteroids, whereas the NAD(+)-linked enzyme oxidized the 3 alpha-hydroxy group of pregnanes and some bile acids, and the 17 beta-hydroxy group of testosterone and androstanes. The thermal stabilities of the 3 alpha- and 17 beta-hydroxysteroid dehydrogenase activities of the NAD(+)-linked enzyme were identical, and the two enzyme activities were inhibited by mixing 17 beta- and 3 alpha-hydroxysteroid substrates, respectively. Medroxyprogesterone acetate, hexoestrol and 3 beta-hydroxysteroids competitively inhibited 3 alpha- and 17 beta-hydroxysteroid dehydrogenase activities of the enzyme. These results show that hamster liver contains a 3 alpha(17 beta)-hydroxysteroid dehydrogenase structurally and functionally distinct from 3 alpha-hydroxysteroid dehydrogenase.

17-Hydroxysteroid Dehydrogenases↗
PubMed1990

[Effect of concomitant use of anticancer drugs and a Ca2+ antagonist, on human gastric cancer transplanted into nude mice].

We examined the effect of concomitant use of anticancer drugs such as Carmofur or 5-FU and Nicardipine, a Ca2+ antagonist, on human gastric cancer transplanted into nude mice, and obtained the following results: 1. Combined administration of Carmofur or 5-FU together with Nicardipine caused potentiation of an antitumor effect. 2. After Carmofur was used together with Nicardipine, the FU level in the tumor tissue was significantly elevated. In conclusion, it was found that in the combined use of Carmofur or 5-FU together with Nicardipine, a Ca2+ antagonist, caused a higher level of the FU in tumor tissue and potentiation of an antitumor effect on human gastric cancer transplanted into nude mice.

Animals↗
PubMed1990

Effect of second-messenger modulators in K-562 cell differentiation: dual action of calcium/phospholipid-dependent protein kinase in the process of differentiation.

We investigated the roles of second messengers in K-562 cell differentiation induced by either commitment-inducing agents (Ara-C, thymidine), or a noncommitment-inducing agent (hemin). Cell differentiation induced by both types of agents was inhibited by dbc-AMP, staurosporine, and H-7. In contrast, OAG enhanced hemin-induced cell differentiation, but it inhibited that due to Ara-C or thymidine. When K-562 cells were incubated with 4 x 10(-6)M hemin or 2 x 10(-7)M Ara-C for 2 days, an increase of epsilon-mRNA occurred. The addition of cycloheximide (1 microgram/ml) completely blocked this change, suggesting that de novo protein synthesis was necessary for the increase of epsilon-mRNA. Simultaneous treatment with Ara-C and cycloheximide for 2 days did not block either the increase of epsilon-mRNA or that of benzidine-positive cells, which were measured after 5 days of further incubation without additives. This suggested that the process of Ara-C-induced K-562 cell differentiation could be divided into two steps, i.e., a commitment step and a phenotypic expression step, and that the commitment step was at least partly resistant to cycloheximide. We investigated the roles of second messengers in each step. Our results suggested that PKC may act as a negative regulator of commitment step and as a positive regulator of the phenotypic expression. This may explain the differing effects of OAG on hemin- and Ara-C-induced K-562 cell differentiation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

Trypsin-like hatching protease from mouse embryos: evidence for the presence in culture medium and its enzymatic properties.

Enzymatic properties of a protease involved in hatching of mouse embryos were examined. A trypsin-like protease, which most efficiently hydrolyzed t-butoxycarbonyl-Leu-Ser-Thr-Arg-4-methylcoumaryl-7-amide, was demonstrated in culture medium of mouse hatching embryos. The enzyme was strongly inhibited by diisopropyl fluorophosphate, phenylmethanesulfonyl fluoride, leupeptin, antipain, N alpha-tosyl-L-lysyl-chloromethane, soybean trypsin inhibitor, and Trasylol, but not or weakly inhibited by p-chloromercuribenzoic acid, EDTA, E-64, pepstatin, chymostatin, and bestatin, suggesting a trypsin-like serine proteinase. The protease activity in the medium gradually elevated during the course of hatching, whereas the embryo-associated activity showed no significant change. Furthermore, pyroglutamyl-Leu-argininal, the strongest inhibitor for the enzyme among peptidyl argininals, all of which are potent trypsin inhibitors, showed the strongest inhibition toward hatching. Thus, a trypsin-like protease secreted from hatching embryos into the culture medium may participate in mouse hatching, probably as a hatching enzyme.

Animals↗
PubMed1990

Mechanism of the stimulatory effect of cyclodextrins on lankacidin-producing Streptomyces.

Gel-filtration analysis of a mixture of cyclodextrin (CyD) and lankacidin C showed that beta-CyD had strong, gamma-CyD weak and alpha-CyD no affinity for lankacidin C. Lankacidin C production activity, which was assayed by measuring the incorporation of L-[methyl-14C-]methionine into the lankacidin molecule, was the greatest with cells grown in the presence of beta-CyD, less with gamma-CyD and the least with alpha-CyD. Lankamycin and T-2636M, which are by-products in lankacidin C fermentation, were not included by beta-CyD and their production was not stimulated by beta-CyD. It was apparent that the stimulatory effect of CyD was closely related to the formation of an inclusion complex between CyD and the antibiotic. Lankacidin C biosynthesis was repressed by preincubating cells with lankacidin C, while the repressive effect of lankacidin C was abrogated by the inclusion by beta-CyD. Thus, abrogation of feed-back repression seems to be a main mechanism of the effect of CyD. However, alpha-CyD, which had no affinity for lankacidin C, stimulated the production to the least extent and exhibited a complementary effect on the stimulation by beta-CyD or gamma-CyD, alpha-CyD also caused a change in cell morphology and cell-surface hydrophobicity. It was assumed that the modification of the cell surface is a secondary mechanism of the effect of CyD.

Anti-Bacterial Agents↗
PubMed1990

MRI demonstration of cortical laminar necrosis and delayed white matter injury in anoxic encephalopathy.

We performed serial radiological examinations on a patient with anoxic encephalopathy. In the early term after the anoxic insult, T1-weighted MRI revealed high signal intensity areas distributed laminarly in the cerebral cortex and diffusely in the putamen, which were thought to reflect the cortical necrosis and necrosis in the putamen. Single photon emission computed tomography using I-123 isopropylamphetamine showed persistent hypoperfusion in the arterial watershed zones. T2-weighted MRI performed several months after the anoxic episode revealed diffuse high-intensity lesions in the arterial water-shed zones. These delayed-onset white matter lesions continued to extend over several months.

Adult↗