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Biomedical subjects

K Takada

Publications and source records attributed to K Takada.

At least 775 records · Page 43Linked to original sources
PubMed1985

Kinetic studies on surface-mediated activation of bovine factor XII and prekallikrein. Effects of kaolin and high-Mr kininogen on the activation reactions.

The kaolin-mediated reciprocal activation of bovine factor XII and prekallikrein was divided into the following two reactions: the activation of factor XII by plasma kallikrein (reaction 1) and the activation of prekallikrein by factor XIIa (reaction 2). The effects of high-Mr kininogen and kaolin surface on the kinetics of these activation reactions were studied. High-Mr kininogen markedly enhanced the rate of reactions 1 and 2 in the presence of kaolin, and the enhancements were highly dependent on the concentrations of the protein cofactor and amount of kaolin surface. For the activation of factor XII by plasma kallikrein (reaction 1), high-Mr kininogen was required when a low concentration of factor XII and kaolin was used. The molar ratio of the protein cofactor to factor XII for optimal activation was found to be approximately 1:1. The apparent Km value and the kcat/Km value for plasma kallikrein on factor XII were calculated to be 4 nM and 5.2 X 10(7) s-1 X M-1, respectively. The activation of prekallikrein by factor XIIa, (reaction 2) proceeded even in the absence of high-Mr kininogen and kaolin. The addition of the protein cofactor and surface to the reaction mixture remarkably accelerated the reaction, and the apparent Km value for factor XIIa on prekallikrein was reduced from 1 microM to 40 nM. Moreover, the kcat/Km value was altered from 7.3 X 10(4) to 1.1 X 10(6) s-1 X M-1). These results suggest that high-Mr kininogen accelerates the surface-mediated activation of factor XII and prekallikrein by enhancing the susceptibility of factor XII to plasma kallikrein, on the one hand, and the affinity of factor XIIa for prekallikrein, on the other hand. Kaolin may play an important role in the concentration and organization of these components on the negatively charged surface.

Amidohydrolases↗
PubMed1985

Dentoskeletal and tongue soft-tissue correlates: a cephalometric analysis of rest position.

The relationship between dentoskeletal and tongue soft-tissue variables has been quantified in a sample of 60 adult females with normal and anterior open-bite malocclusions. Three lateral rest-position head films were obtained for each subject. A principal component analysis reduced the data base and six significant canonical correlations were identified. The first canonical correlation (r1 = 0.962) represented a size-related correlation factor between the two groups of variables. Subjects with characteristics of a short face syndrome and some evidence of overbite had tongue tips positioned below the lower occlusal plane (r2 = 0.929). In contrast, skeletal open-bite subjects (r4 = 0.759) revealed tongue tips ahead of and above the lower incisor teeth with the mandible in the rest position. Undererupted mandibular teeth (r5 = 0.666) were associated with a reduced tongue height and an inferior epiglottis; short tongue length (r6 = 0.563) correlated with a linear combination of upright central incisors, a small overjet, a low ANB angle, unerupted maxillary and mandibular teeth, and a steep occlusal plane. The multivariate statistical analysis extracted clinically significant associations between tongue soft-tissue and dentoskeletal variables. Tongue posture at rest in skeletal open-bite subjects appeared to be related to incisor position.

Adolescent↗
PubMed1985

Development and validation of a salmon prolactin radioimmunoassay.

A highly specific radioimmunoassay (RIA) for the measurement of prolactin (PRL) in the plasma and pituitary of salmonid fishes was developed using a rabbit antiserum to chinook salmon (Oncorhynchus tschawytscha) PRL. The PRLs purified from chinook salmon and chum salmon (O. keta) pituitaries showed exactly the same competitive inhibition curves in the RIA, regardless of iodination of either hormone. The displacement curves for pituitary extracts and plasma from several salmonids, including chum, coho, and amago salmon, rainbow trout, and Japanese charr, were parallel to the salmon PRL standard, whereas those from the eel, goldfish, carp, and tilapia showed negligible cross-reactivity. Negligible cross-reactivity was also seen with plasma from hypophysectomized rainbow trout or coho salmon. None of the mammalian PRL or growth hormone (GH) preparations, bullfrog PRL, or presumptive chum salmon "gonadotropin" and eel "PRL" cross-reacted in the PRL RIA. Presumptive chum salmon GH showed less than 0.05% cross-reactivity. The RIA sensitivity was less than 0.1 ng of the salmon PRL standard per milliliter. The immunoreactive plasma PRL levels in mature chum salmon were below 1 ng/ml in seawater. The plasma PRL in females increased to about 8 ng/ml 1 day after transfer to fresh water, and high levels (2-4 ng/ml) were maintained during 3-7 days after the transfer. In contrast, when males were transferred to fresh water, an increase in plasma PRL was seen only 1 day after the transfer. A significant decrease in plasma osmolality was observed in both males and females after transfer to fresh water. No change was observed either in plasma PRL or osmolality, when fish were transferred from seawater to seawater.

Animals↗
PubMed1985

Optimal dosage regimen calculation program based on the remaining drug concentrations in plasma.

A program is presented to calculate the optimal drug doses to make the plasma drug concentration at a constant level throughout the therapy. The package requires data input of experimentally determined pharmacokinetic parameters such as As and ramdas, and provides the optimal intravenous drug doses at every minute. This program is applicable to any drug in a given individual, provided that the single-dose plasma concentration curve equation of the first dose of the therapy in this individual is known.

Biometry↗
PubMed1985

Giant seminoma of undescended testis in Down syndrome.

A giant seminoma of undescended testis in a forty-one-year-old Japanese male with Down syndrome is reported as is a review of the literature. The relationship between Down syndrome and testicular cancer are discussed. To our knowledge this is the largest seminoma of undescended testis (weight 3,500 Gm) so far recorded.

Adult↗
PubMed1985

Isolation of Fab and Fc fragments from a plasmin-treated human immunoglobulin by high-speed gel filtration on TSK G3000SW and G3000SWG.

A method is described for isolating intact 7S IgG, Fab and Fc fragments from a plasmin-treated immunoglobulin by high-speed gel filtration on a TSK G3000SW or G3000SWG column. The isolated 7S IgG, Fab and Fc fragments reacted with antihuman IgG, Fab and Fc antiserum, respectively, in both Ouchterlony's double immunodiffusion and immunoelectrophoresis. Each of the Fab and Fc fragments formed a single precipitation line, demonstrating their homogeneity. Anticomplementary activities of intact 7S IgG, Fab and Fc fragments were 2.5, less than or equal to 10 and 2.5 mg protein/ml to inhibit 2 units of CH50, respectively, and the diphtheria antitoxin contents were 2.1, 6.0 and 1.5 IU/150 mg protein, respectively. The molecular composition of plasmin-treated immunoglobulin as determined by gel filtration on a TSK G3000SW column was as follows: 7S IgG 38.0 +/- 0.2%; Fab 42.6 +/- 0.1% and Fc fragment 19.3 +/- 0.1%.

Chromatography, Gel↗
PubMed1985

Inhibition of plaque and caries formation by a glucan produced by Streptococcus mutans mutant UAB108.

A mutant (UAB108) derived from Streptococcus mutans UAB66, a spectinomycin-resistant (Spcr) isolate of strain 6715, inhibited plaque formation when grown with strain 6715 in a sucrose medium and also inhibited caries formation in gnotobiotic rats infected with both strain UAB108 and 6715. A substance obtained from UAB108 culture supernatant fluid after ethanol precipitation and DEAE-cellulose treatment, designated glucan 108, inhibited S. mutans 6715 virulence and was shown to be a water-soluble glucan. In the presence of sucrose and increasing concentrations of glucan 108, the activity of a glucosyltransferase (GTase) preparation from S. mutans 6715 to synthesize adhesive water-insoluble glucan (ad-WIG) was inhibited, and the activity to synthesize non-ad-WIG was stimulated. Glucan 108 similarly inhibited sucrose-dependent adherence of heat-treated cells, was a poor inducer of cell aggregation, and inhibited S. mutans 6715-induced dental caries in gnotobiotic rats. In the presence of GTase, glucan 108, and sucrose, the glucose moiety of sucrose was found to be incorporated into glucan 108, and most of this glucose-incorporated glucan 108 was found in the non-ad-WIG fraction. The mode of inhibition of plaque formation by S. mutans 6715 appears to involve a shift from ad-WIG to non-ad-WIG formation. The water-soluble glucan 108 was found to have an approximate molecular weight of 2 X 10(6) and was hydrolyzed by fungal dextranase to yield glucans with an average molecular weight of about 1.2 X 10(4). This glucan (designated glucan 12k) was further hydrolyzed by bacterial dextranase to yield smaller glucans and oligosaccharides, but was refractile to alpha (1----3) glucanase. These results suggest that glucan 108 is a branched alpha (1----6) glucan, and it is proposed that UAB108 is defective in its ability to polymerize glucan 12k with alpha (1----3)-linked glucosyl residues.

Adhesiveness↗
PubMed1985

Comparison of disappearance from blood and lymphatic delivery of human fibroblast interferon in rat by different administration routes.

Disappearance from the blood and lymphatic delivery of human fibroblast interferon (HuIFN-beta) in rats by the various administration routes were studied. Intravenous injection showed a rapid disappearance of HuIFN-beta from the blood circulation, however, the clearance rate was greatly decreased after 2 h and the half-lives were 15 min and 2.0 h. Intramuscular, subcutaneous and intraperitoneal injections maintained readily detectable levels in the blood for 12 h, and the half-lives were 2.3, 1.7 and 1.2 h, respectively. Lipid-surfactant mixed micelles greatly promoted the absorption of HuIFN-beta from the large intestine with extremely high selective lymphatic delivery, whereas intravenous and intramuscular injections showed no selective transfer into the lymphatics.

Animals↗
PubMed1985

Potentiation of antitumor effect of bleomycin by lipid-surfactant mixed micelles. I. In vivo and tumor-neutralizing activity against mouse Ehrlich ascites tumor and rat ascites hepatoma AH66.

Mixed micelles (MM) composed of polyoxyethylated (60 mol) hydrogenated castor oil (HCO60) as a harmless surfactant and linoleic acid (LA) as an essential fatty acid potentiated the antitumor activity of bleomycin (BLM). In the in vivo experiment, intraperitoneal administration of BLM with MM significantly prolonged the survival time of male ddY mice bearing Ehrlich ascites tumor and male Donryu rats bearing ascites hepatoma AH 66 inoculated intraperitoneally, compared with that of animals treated with BLM alone, BLM with HCO60, and BLM with LA, respectively, whereas MM had no antitumor effect to both tumors. Also in Winn-type tumor-neutralizing assay in which 10 male ddY mice were innoculated intraperitoneally with Ehrlich ascites tumor cells preincubated with a test material, BLM with MM showed a more marked enhancing activity with 3 surviving tumor-free mice than did BLM alone.

Animals↗
PubMed1985

Promotion of the selective lymphatic delivery of cyclosporin A by lipid-surfactant mixed micelles.

The absorption of an immunosuppressive drug, cyclosporin A (CsA), with the aid of lipid-surfactant mixed micelles from the rat gastrointestinal (GI) tract and lymphatic delivery were studied. The administration of CsA in oily solution, sesame oil or linolic acid, into the rat duodenum indicated a small amount of CsA both in the plasma and lymph for about 6 h. The administration of CsA in the mixed micellar solution composing of linolic acid and HCO-60, polyoxyethylated (60 mol) hydrogenated castor oil, accelerated the absorption of CsA from the GI tract, and CsA was delivered into the lymphatics with an extremely high selectivity.

Animals↗
PubMed1985

Enhancing effect of absorption promoters on percutaneous absorption of a model dye (6-carboxyfluorescein) as poorly absorbable drugs. II. Study on the absorption promoting effect of azone.

The percutaneous absorption of drugs was investigated in rats by measuring plasma levels, using mainly 6-carboxyfluorescein (CF) as a model of poorly absorbable drugs. Azone (AZ), a new useful promoter for the percutaneous absorption of drugs, was used instead of dimethylsulfoxide. We have examined the effects of the solubilized state and concentration of AZ on the percutaneous absorption of CF. AZ was dissolved with the aid of surface-active agents, beta-cyclodextrin (CD) or dimethyl-beta-cyclodextrin (DMCD). When AZ (2 v/v%) was dissolved completely by a surface-active agent (HCO-60: polyoxyethylene hardened castor oil derivative), plasma CF levels showed the highest value. Plasma CF levels following the administration of CF with AZ which formed a complex with CD or DMCD were scarcely increased as compared to that of CF alone. In the case of fluorescin (FL), which has a higher partition coefficient than CF, the percutaneous absorption of FL was more enhanced by the addition of AZ than in the case of CF.

Adjuvants, Pharmaceutic↗