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Biomedical subjects

H Okada

Publications and source records attributed to H Okada.

At least 1,117 records · Page 62Linked to original sources
PubMed1983

Vaginal absorption of a potent luteinizing hormone-releasing hormone analogue (leuprolide) in rats II: mechanism of absorption enhancement with organic acids.

Organic acids such as citric acid enhance the vaginal absorption of luteinizing hormone-releasing hormone, the potent analogue (leuprolide), and insulin. The mechanism of this absorption enhancement was investigated with leuprolide and hydrophilic markers such as phenol red and Evan's blue. The absorption of the analogue was increased by lowering the pH of the solution and increased more by adding citric, succinic, tartaric, and malonic acids. The absolute bioavailability after vaginal administration of the 5% citric acid solution was 16.7% at pH 3.5 and 38.4% at pH 1.8. The enhancing potency of the absorption correlated well with the chelating ability of the organic acids. The vaginal absorption of phenol red was also enhanced with citric acid and edetic acid, but the enhancing effect of edetic acid was eliminated by adding equimolar calcium ion. These results suggest that the acidifying and chelating abilities of the acids may result in a potent enhancement of the vaginal absorption of leuprolide. A leakage experiment using Evan's blue on the vaginal membrane indicated that the blood-vaginal epithelium barrier was loosened with the administration of citric acid; this change was overcome rapidly.

Absorption↗
PubMed1983

Vaginal absorption of a potent luteinizing hormone-releasing hormone analogue (leuprolide) in rats III: Effect of estrous cycle on vaginal absorption of hydrophilic model compounds.

The effect of estrous cycle stages on vaginal absorption was determined by the use of insulin, phenolsulfonphthalein, and salicylic acid as hydrophilic model compounds. Absorption of these compounds was markedly affected by the stage, possibly due to the change of transport rate through the pore-like pathways. The absorption of phenolsulfonphthalein during proestrus and estrus is roughly one-tenth of that during metestrus and diestrus. An increase of the nonionized form of salicylic acid, produced by a lowered pH, resulted in an enhancement of absorption during proestrus and diestrus; higher contribution of the transport through the cell membrane possibly reduced an effect of the estrous cycle. However, consecutive daily administration of leuprolide halted the cycle at diestrus and reduced the cycle effect on the vaginal absorption of phenolsulfonphthalein; when the treatment was started at any of the four stages of the cycle, vaginal absorption was enhanced approximately 20%, with less variance than that observed in normal diestrous rats.

Animals↗
PubMed1983

Molecular cloning of the genes for xylan degradation of Bacillus pumilus and their expression in Escherichia coli.

The 7.7 Mdal PstI fragment of Bacillus pumilus IPO containing genes for xylan degradation, xylanase, and beta-xylosidase was inserted at the PstI site of pBR322 and cloned in E. coli C600. The hybrid plasmid thus formed was named pOXN29. The amount of xylanase and beta-xylosidase expressed in E. coli harboring pOXN29 was about 6% and 20% of the activity produced by the donor, B. pumilus. The reverse orientation of the inserted fragment resulted respectively in 5 times and 50 times increases in xylanase and beta-xylosidase productivities. Both enzymes expressed in E. coli transformants were shown to be indistinguishable from those of B. pumilus by immunological and chemical criteria. Digestion of pOXN29 with BglII produced two fragments; one was 6.7 Mdal in size and contained the whole pBR322 and the beta-xylosidase gene, and the other was 3.7 Mdal and coded for xylanase. Analysis of enzymes expressed in the transformant cells indicated that neither enzyme was secreted into the culture medium, periplasm nor membrane bound, although xylanase but not beta-xylosidase, was secreted into the medium in a B. pumilus culture.

Bacillus↗
PubMed1983

Induction and subcellular localization of enzymes participating in propionate metabolism in Candida tropicalis.

Candida tropicalis, a representative alkane- and higher fatty acid-utilizing yeast, can grow on propionate used as sole carbon and energy source. Initial pH of the medium markedly affected the growth of the yeast on propionate. In propionate-grown cells, several enzymes associated with peroxisomes and/or participating in propionate metabolism were induced in connection with the appearance of the characteristic peroxisomes. Acetate-grown cells of this yeast had only few peroxisomes, while alkane-grown cells contained conspicuous numbers of the organelles. As compared with alkane-grown cells, some specific features were observed in peroxisomes and enzymes associated with the organelles of propionate-grown cells: The shape of peroxisomes was large but the number was small; unlike localization of catalase in peroxisomes of alkane-grown cells, the enzyme of propionate-grown cells was mainly localized in cytoplasm; as for carnitine acetyltransferase localized almost equally in peroxisomes and mitochondria in alkane-grown cells, propionate-grown cells contained mainly the mitochondrial type enzyme. A propionate-activating enzyme, which was different from acetyl-CoA synthetase, was also induced in cytoplasm of propionate-grown cells. The role of carnitine acetyltransferase and the propionate-activating enzyme in propionate metabolism is discussed in comparison with the role of carnitine acetyltransferase and acetyl-CoA synthetase in acetate metabolism.

Candida↗
PubMed1983

Suppression and stimulation of mineralocorticoid hormones (MCH) in the simple virilizing form of congenital adrenal hyperplasia (CAH) evaluated by the quantitation in adrenal venous blood.

Four untreated female patients with the nonsalt-losing form of congenital virilizing adrenal hyperplasia (21-hydroxylase deficiency) (21-OHD) maintained on a daily sodium intake of 120 m-equiv were studied by bilateral adrenal vein catheterization. Simultaneous right and left adrenal and peripheral blood samples were collected for determination of cortisol (F), progesterone (P), 17-hydroxyprogesterone (17-OHP), aldosterone (Aldo), and deoxycorticosterone (DOC). All patients were studied during sequential ACTH suppression (30 min after intravenous administration of 4 mg of dexamethasone) and stimulation (5 min after intravenous administration of 250 micrograms beta-ACTH [cosyntropin]). Basal peripheral concentrations of Aldo, DOC, P and 17-OHP were increased, whereas F concentrations were in the lower limit of the normal range. Dexamethasone suppressed adrenal secretion in all subjects. Subsequent adrenal stimulation by ACTH increased P, 17-OHP and DOC, whereas F returned to only control levels. DOC responses to ACTH in the adrenal vein effluents correlated significantly with Aldo responses but not with the 17-OHP increments, suggesting that the adrenal responses of Aldo and DOC to ACTH are events that probably occur in the same zone.

17-alpha-Hydroxyprogesterone↗
PubMed1983

Activation of the alternative complement pathway by IgM antibody reacted on paragloboside incorporated into liposome membrane.

Liposomes containing paragloboside (PG) on their membrane were readily lysed by C4 deficient guinea pig serum (C4D-GPS). On the other hand, guinea pig serum from specific pathogen free Hartley guinea pigs (SPF-GPS) did not lyse PG-liposomes in Mg-EGTA-GVB (gelatin veronal buffered saline containing MgCl2 and ethyleneglycol-bis(beta-aminoethyl ether)N,N'-tetraacetate) which permits complement activation via the alternative pathway but not via the classical pathway. However, the SPF-GPS could lyse the liposomes in Mg-EGTA-GVB when heated (56 degrees C, 30 min) C4D-GPS or other guinea pig serum (GPS) was added. Gel filtration of Hartley (Htl)-GPS through a Sephadex G-200 column revealed that IgM antibody to PG in Htl-GPS was responsible for sensitization of the liposomes to lysis by complement of SPF-GPS via the alternative pathway. This result indicated that guinea pig IgM antibody can initiate the activation of the alternative pathway of homologous complement on liposome membrane.

Animals↗
PubMed1983

Differing reactivities of human and guinea-pig complement on haptenized liposomes via the alternative pathway.

Several haptens coupled to dipalmitoylphosphatidylethanolamine (DPPE) were inserted into the liposome membrane with a base composition of an equimolecular mixture of dimyristoylphosphatidylcholine (DMPC) and cholesterol (Chol). Haptens used were trinitrophenyl (TNP)-DPPE, TNP-aminocaproyl (TNP-Cap)-DPPE, dinitrophenyl (DNP)-DPPE, DNP-aminocaproyl (DNP-Cap)-DPPE, fluoresceinthiocarbamyl (Fl)-DPPE, azobenzenarsonate-tyrosyl (ABA-Tyr)-DPPE, dansyl (DNS)-DPPE, dabsyl (DABS)-DPPE, dithiopyridyl (DTP)-DPPE and maleimidobenzoyl (MB)-DPPE. Reactivity of those haptenized liposomes with complement via the alternative pathway was assessed by release of trapped fluorescent marker from the liposomes following incubation with dilutions of guinea-pig and human sera in a diluent containing MgCl2 and ethyleneglycol-bis(beta-aminoethyl ether)N,N'-tetraacetate (EGTA). In the diluent (Mg-EGTA-GVB), complement activation via the alternative pathway proceeds while that via the classical pathway is inhibited. Fl-liposomes were found to be extremely sensitive to guinea-pig complement, being lysed by guinea pig serum dilutions of up to 1:76 in Mg-EGTA-GVB. Guinea-pig serum could lyse TNP-Cap-liposomes, DNP-Cap-liposomes, TNP-liposomes, DTP-liposomes, MB-liposomes, DNP-liposomes and ABA-Tyr-liposomes, with the reactivity of the liposomes decreasing in this order. However, the only haptenized liposomes sensitive to human serum in Mg-EGTA-GVB were DTP- and MB-liposomes; the other liposomes including Fl-liposomes being unreactive via the alternative pathway in reaction with human complement.

Animals↗
PubMed1983

Species-specific inhibition by glycophorins of complement activation via the alternative pathway.

Glycophorin, one of the major glycoproteins of erythrocytes (E), was extracted from human E (glycophorin-Hu) and guinea pig E (glycophorin-GP) and adsorbed to rabbit-E. The adsorption of glycophorin-Hu and glycophorin-GP to rabbit-E made the E resistant to hemolysis by human serum and guinea pig serum, respectively, via the alternative complement pathway (ACP). However, it did not make the rabbit-E resistant to hemolysis by serum heterologous to the glycophorin adsorbed. This species-specific inhibition by glycophorin of ACP activation should play a role in restricting ACP activation on self cell membranes. By recognizing the self-cell surface as the place where the complement reaction must be prevented, ACP will be able to accomplish the discrimination of non-self constituents without diversity of recognition sites for a variety of foreign substances.

Animals↗
PubMed1983

Serum hormone and steroid hormone receptor levels during luteal-phase and long-term treatment with danazol.

This study was designed to clarify the effects of danazol on levels of serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin, progesterone (P), and 17 beta-estradiol and endometrial steroid receptors (for estrogen [ER], progestin [PR], and androgen [AR] ) during luteal-phase and long-term treatment. These levels were compared with midluteal-phase levels for a histologically in-phase endometrium. Danazol given during the luteal phase to patients with in-phase endometrium decreased endometrial steroid receptor levels (total ER and total PR), and decreased serum P, LH, and FSH levels. Ten of the 17 patients treated (59%) still had in-phase endometrium. Danazol (400 mg/day) given for 1 month or more to patients with pelvic endometriosis increased serum LH and FSH levels within the normal range and endometrial total ER and PR levels. It appears that the effects of short-term and long-term treatment with danazol on serum hormone and endometrial steroid receptor levels differ.

Adult↗
PubMed1983

Lymphoid cell responses to bacterial cell wall components: murine B-cell responses to a purified cell wall moiety of Actinomyces.

A mitogenic component, designated fraction C (Fr C), has been purified from a mutanolysin enzyme digest of Actinomyces cell walls by CM Sephadex C-25 ion-exchange and G-100 gel filtration chromatography. Good mitogenic responses were obtained with Fr C over a broad dose range with peak mitogenesis seen with 500 micrograms/culture. Fraction C (mol. wt. = 35,000-40,000) consists of 75% carbohydrate and 23% protein, is non-dialysable, resistant to heat, lysozyme or protease treatment, and partially sensitive to base, and all mitogenic activity is destroyed by either periodate or acid treatment. Fraction C is a B-cell mitogen since it induced responses in nude (nu/nu) and nu/+ BALB/c spleen cell cultures and purified splenic B-cell cultures, but did not stimulate purified splenic T-cell cultures. Similar mitogenic fractions for B cells have been obtained from cell walls of A. naeslundii and from a human isolate of A. viscosus. Good polyclonal IgM synthesis and plaque-forming cell responses to hapten or erythrocytes were obtained in vitro with the purified cell wall fractions derived from all three Actinomyces strains studied. These results indicate that the Actinomyces cell wall possesses a carbohydrate-rich component which activates B cells and may represent a common determinant of this genus.

Actinomyces↗
PubMed1983

Identification and distribution of immunocompetent cells in inflamed gingiva of human chronic periodontitis.

Advanced human periodontitis is considered to be a B-cell lesion, but the cellular infiltrate contains several cell types, the distribution of which has not been determined. This experiment was designed to characterize and identify the immunocompetent cells on histological sections and in eluates from diseased human gingiva. Immunoglobulin-bearing cells were detected on histological sections by direct immunofluorescence with F(ab')2 antisera monospecific for human immunoglobulin G (IgG), IgA, or IgM. Plasma cells predominated in the central portion of the lamina propria, with the proportions positive for IgG, IgA, and IgM accounting for 65.2 +/- 9.5, 11.2 +/- 1.1, and 1.3 +/- 1.1% of the total infiltrating cells, respectively. T lymphocytes, identified by indirect immunofluorescence with monoclonal antibody (Leu-1) against human T cells, accounted for 29.3 +/- 10.0% of the total infiltrated cells. Most of the T cells were located subjacent to the pocket epithelium, but there were a few in the central lamina propria. Similarly, Fc receptor-bearing cells detected by EA rosetting and macrophages and monocytes detected by nonspecific esterase staining with alpha-naphthylbutyrate esterase were also localized to the region immediately subjacent to the pocket epithelium. Infiltrated cells were harvested from minced gingival tissue after digestion with collagenase, hyaluronidase, and DNase. The eluates contained 35.3 +/- 6.0% T lymphocytes, 30.0 +/- 14.9% Fc receptor-bearing cells, and 12.9 +/- 4.4% monocytes and macrophages. Whereas T gamma cells comprised 13.3 +/- 1.4% of peripheral blood T cells, they accounted for only 6.0 +/- 2.0% of the eluate T cells. In contrast, T mu cells accounted for 44.7 +/- 4.9% of the T cells in the eluates and 51.6 +/- 4.4% in the peripheral blood. The decreased proportion of T gamma cells in the gingiva may indicate a form of abnormal immune regulation concerned with T suppression of B-cell proliferation.

Adult↗
PubMed1983

Plasmid-determined enzymatic degradation of nylon oligomers.

The nylon oligomer (6-aminohexanoic acid cyclic dimer) degradation genes on plasmid pOAD2 of Flavobacterium sp. KI72 were cloned into Escherichia coli vector pBR322. The locus of one of the genes, the structural gene of 6-aminohexanoic acid linear oligomer hydrolase, was determined by constructing various deletion plasmids and inserting the lacUV5 promoter fragment of E. coli into the deletion plasmid. Two kinds of repeated sequences (RS-I and RS-II) were detected on pOAD2 by DNA-DNA hybridization experiments. These repeated sequences appeared five times (RS-I) or twice (RS-II) on pOAD2. One of the RS-II regions and the structural gene of the hydrolase overlapped.

Amidohydrolases↗
PubMed1983

Human rotavirus detection by agglutination of antibody-coated erythrocytes.

We sensitized sheep erythrocytes (SRBC) with antibodies against human rotavirus strain Wa (SRBC-antiWa) and antibodies against calf rotavirus strain NCDV (SRBC-antiNCDV). These were readily agglutinated in the presence of homologous antigens, i.e., human rotavirus and calf rotavirus. By the hemagglutination of SRBC-antiWa and SRBC-antiNCDV (reverse passive hemagglutination [RPHA]), titration of rotavirus in extracts from feces of children suffering from diarrhea (61 specimens) was carried out. We found that the ratio of titers determined with SRBC-antiWa and SRBC-antiNCDV varied remarkably from specimen to specimen. This indicated that the antigenic determinants on human rotavirus in patients feces cross-react with antibodies against NCDV to varying extents. To express the cross-reactivity of human rotavirus with antibodies to NCDV, we propose a Wa/NCDV rotavirus index which can be calculated from the RPHA titer with SRBC-antiWa and SRBC-antiNCDV as follows: Wa/NCDV rotavirus index = (antiWa-RPHA titer of specimen/antiWa-RPHA titer of NCDV)/(antiNCDV-RPHA titer of specimen/antiNCDV-RPHA titer of NCDV).

Antibodies, Viral↗
PubMed1983

Macrocyst development in Dictyostelium discoideum. II. Mating-type-specific cell fusion and acquisition of fusion-competence.

The early events of macrocyst development in Dictyostelium discoideum have been investigated using a new culturing system. When cells of opposite mating-types, HM1 and NC4, are cultured together at the appropriate temperature in the dark, giant cells appear, ingest the surrounding amoebae, and develop into macrocysts. Although these giant cells have been assumed to be the products of the fusion of opposite mating-type cells, no experimental evidence to prove this assumption has been obtained using such mixed-culture systems. In order to avoid the complexities involved in mixed-culturing, we have developed a new system involving the separate culture, and later mixing, of opposite mating-type cells. This has enabled us to obtain direct evidence that giant cells are produced by fusion between opposite mating-type cells. Cell fusion occurs immediately after mixing and is completed within 30 min. As a number of cells fuse simultaneously, giant cells produced by this method are very large multinucleated cells, and not binucleated zygotes. Using this system we also discovered the following facts related to giant cell formation: (1) cells can acquire their fusion competence without the presence of cells of the opposite mating-type; (2) only HM1 cells require darkness to acquire their fusion competence; (3) the restrictive temperature, 25 degrees C, inhibits the induction of fusion competence in HM1 cells, but not in NC4 cells.

Darkness↗