Biomedical subjects

T Takaya

Publications and source records attributed to T Takaya.

At least 73 records · Page 4Linked to original sources

PubMed1986

Studies on beta-lactam antibiotics. XI. Synthesis and structure-activity relationships of new 3-(2,2-dihalovinyl)cephalosporins.

The synthesis and in vitro antibacterial activity of 7 beta-[(Z)-2-(2-amino-4-thiazolyl)-2-carboxymethoxyiminoacetamido]- 3-(2,2-dihalovinyl)cephalosporins are described. 3-(2,2-Dihalovinyl)cephalosporins exhibited excellent antimicrobial activity against both Gram-positive and Gram-negative bacteria, especially showed higher activity against Staphylococcus aureus than the corresponding 3-vinylcephalosporin.

Animals↗

PubMed1986

Studies on beta-lactam antibiotics. XII. Synthesis and activity of new 3-ethynylcephalosporin.

The synthesis of the orally absorbed 3-ethynylcephalosporin is described. In addition, the structure-activity relationships and oral absorption in rats of 7 beta-[(Z)-2-(2-amino-4-thiazolyl)-2- carboxymethoxyiminoacetamido]cephalosporins having various aliphatic hydrocarbon groups at the 3-position are discussed. Of these cephalosporins, 3-ethynyl-cephalosporin exhibited better activity against Staphylococcus aureus than the other cephalosporins and showed moderate oral absorption in rats.

Absorption↗

PubMed1986

Studies on beta-lactam antibiotics. XIII. Synthesis and structure-activity relationships of 7 beta-[(Z)-2-aryl-2-carboxymethoxyiminoacetamido]-3-vinylcepha losporins .

The synthesis, antibacterial activity and oral absorption of the 7 beta -[(Z)-2-aryl-2-carboxymethoxyiminoacetamido]-3- vinylcephalosporins are described. Of these cephalosporin derivatives, 7 beta-[(Z)-2-(2-amino-4-thiazolyl)-2-carboxymethoxyiminoacetamido]- 3-vinylcephalosporin exhibited the highest activity against Gram-negative bacteria and showed also good excretion after oral administration to rats. In addition, the effects on the antibacterial activity and oral absorption of the amino function on the thiazole ring are discussed.

Absorption↗

PubMed1985

Pulmonary blood volume and pulmonary extravascular water volume in men.

In order to estimate the pulmonary blood volume between the pulmonary artery trunk and the left atrium (PBV PAT-LA), simultaneously with the pulmonary extravascular water volume (PEWV) in the chronically stable cardiac patients, we employed the double indicator dilution method using heat as a diffusible indicator and indocyanine green as a non-diffusible indicator. The PEWV was obtained as the extravascular lung thermal volume estimated in the aortic root (LTVAo). In the group of hemodynamically normal patients, in spite of ischemic heart disease (G-N, n = 22), the mean pulmonary artery wedge (PAW) pressure was 9.3 +/- 3.9 mmHg (mean +/- SD), PBVPAT-LA was 8.95 +/- 1.71 ml/kg, LTVAo was 5.71 +/- 1.37 ml/kg and PBVPAT-LA/LTVAo ratio was 1.64 +/- 0.44. In the group of hemodynamically slightly compromised patients with mitral stenosis (G-MS, n = 13), the mean PAW pressure was 14.2 +/- 2.6 mmHg, PBVPAT-LA was 11.12 +/- 2.86 ml/kg, LTVAo was 5.68 +/- 1.41 ml/kg and PBVPAT-LA/LTVAo ratio was 2.02 +/- 0.58. Between the two groups, LTVAo was not statistically significant, whereas the mean PAW pressure, PBVPAT-LA and PBVPAT-LA/LTVAo ratio were all significantly increased in G-MS (p less than 0.05). Neither PBVPAT-LA nor LTVAo correlated with the mean PAW pressure in both groups. From PBVPAT-LA/LTVAo ratio, fluid volume in the intravascular space was greater than that in the extravascular space in both groups. From LTVAo, PEWV in G-MS was identical with that in G-N, in spite of the elevated mean PAW pressure. Therefore, even in the patients with mitral stenosis, the interstitium in the lung is kept "dry" under conditions of the mean PAW pressure below 20 mmHg. The safety factors that prevent pulmonary edema, as evidenced in animal studies, seem to operate effectively in man.

Blood Volume↗

PubMed1985

Studies on antiviral agents. II. Synthesis and in vitro antiviral activity on new kanamycin A derivatives having higher acyl group at N-1 position.

The synthesis and antiviral activity of 3''-N-trifluoroacetylkanamycin A derivatives (6) having higher acyl group at the N-1 position are described. On the basis of the structure-activity relationships between antiviral activity and alkyl chain length in an acyl group at the N-1 position, analogs (6f approximately I) having higher alkylcarbonyl group exhibited antiviral activity against not only HSV-I but also influenza virus. Analogs (6q approximately v) having higher alkyloxycarbonyl group showed antiviral activity against HSV-I. In addition, kanamycin A derivatives (6n, o, y, z) possessing higher alkylcarbonyl group with a functional group, higher alkylaminocarbonyl group, and higher alkylthiocarbonyl group had antiviral activity against HSV-I. The analog (6h) showed a broad antiviral spectrum against both DNA (HSV-I, HSV-II, VZV) and RNA (influenza) viruses.

Antiviral Agents↗

PubMed1985

Studies on beta-lactam antibiotics VIII. Structure-activity relationships of 7 beta-[(Z)-2-carboxymethoxyimino-2-arylacetamido]-3-cephem- 4-carboxylic acids.

The synthesis, antimicrobial activity and oral absorptivity of 7 beta-[(Z)-2-carboxymethoxyimino-2-arylacetamido]-3-cephem-4- carboxylic acids are described. The [(Z)-2-(2-amino-4-thiazolyl)-2-carboxymethoxyimino]acetyl group was selected as the most suitable 7-substituent from seven 7-acyl groups for our further investigation of orally active cephalosporins.

Animals↗

PubMed1985

Total synthesis of 3-O-demethylsporaricin A.

The novel, semisynthetic pseudodisaccharide antibiotic, 3-O-demethylsporaricin A, was synthesized via 3-O-demethylsporaricin B obtained by glycosidation of its aminocyclitol part. The aminocyclitol part was synthesized as D,L-form from D,L-(1,2,3/4,5,6)-1,4-bis(benzyloxy-carbonylamino)-5,6-O-isopropyl idene-2,3,5,6-cyclohexanetetraol via three key steps, namely, deoxygenation, inversion of a hydroxyl group, and N-methylation. The physical and biological properties of synthetic 3-O-demethylsporaricin A and an authentic sample derived from sporaricin B were identical.

Aminoglycosides↗

PubMed1985

Studies on antiviral agents. III. Synthesis and in vitro antiviral activity of 1-N-higher-acyl-3"-N-functionalized acylkanamycin A derivatives.

The synthesis and antiviral activity of 1-N-palmitoyl- or 1-N-(3-hydroxytetradecanoyl)-kanamycin A derivatives (7,8) having various type of acyl substituents at the N-3" position were investigated. The structure-activity relationships between the antiviral activity and the substituent at the N-3" position is described. In this series, 3"-N-acetyl-1-N-palmitoyl-kanamycin A (7c) showed the excellent antiviral activity against HSV-I and influenza virus. Further, we examined the synthesis and the antiviral activity of 3"-N-glycylkanamycin A derivatives (9) having a higher-acyl group at the N-1 position. The 3"-N-glycyl-1-N-pentadecanoylkanamycin A (9a) also exhibited excellent antiviral activity.

Amikacin↗

PubMed1985

Studies on beta-lactam antibiotics. IX. Synthesis and biological activity of a new orally active cephalosporin, cefixime (FK027).

The synthesis and some biological properties of 7 beta-[(Z)-2-(2-amino-4-thiazolyl)-2-(carboxymethoxyimino) acetamido]-3-vinyl-3-cephem-4-carboxylic acid (3, FK027) are described. Diphenylmethyl 7-amino-3-vinyl-3-cephem-4-carboxylate hydrochloride (8), the cephem precursor to FK027 was prepared from 7-aminocephalosporanic acid (7-ACA) by two parallel routes differing primarily in the protection of the 7-amino group. Compound 8 was alternatively prepared from deacetylcephalosporin C sodium salt (DCCNa) with improved yields. Two pathways for the conversion of 8 to FK027 are provided. The new orally active cephalosporin, FK027, possesses a widely expanded antimicrobial activity and high stability to beta-lactamases.

Administration, Oral↗

PubMed1985