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Biomedical subjects

J Shimada

Publications and source records attributed to J Shimada.

At least 199 records · Page 11Linked to original sources
PubMed1986

[Human and animal studies on the pharmacokinetics of norfloxacin in renal failure].

The pharmacokinetics of norfloxacin (NFLX) was studied in 5 patients with chronic renal failure and rats with renal obstruction. The drug was orally given to patients on on- and off-dialysis days in a crossover fashion. Serum levels of NFLX showed a similar profile during both on- and off-dialysis days, and the hemodialysis treatment did not affect the elimination of the drug from the serum. The mean serum elimination half-life was 8.8 +/- 1.2 hours (standard error) for on- dialysis day and it was 7.0 +/- 0.8 hours for off-dialysis day. The urinary recovery of NFLX for 24 hours was less than 0.1% of administered doses in these patients. Rats with renal obstruction exhibited higher drug levels in serum for longer periods of time and elevated biliary excretion ratios in comparison to sham-operated rats, and no significant change in the fraction of biliary metabolites was observed. The biliary excretion of NFLX was likely to be enhanced in patients with renal failure.

Administration, Oral↗
PubMed1986

[Pharmacokinetic studies of a new oral cephem T-2588. Pharmacokinetics in gastrectomized volunteers and the renal excretory system in healthy volunteers].

According to the result of the pharmacokinetic examination of T-2588 (esterified prodrug of T-2525) administered to adult male volunteers who have undergone gastrectomy, it appears that the absorption of T-2588 is delayed in the hypoacidity or the anacidity and also the excretion ratio of T-2525A (an inactive metabolite of T-2525) showed a tendency to become higher in these subjects. Again, according to the result of the pharmacokinetic examination of T-2588 when it was administered together with probenecid to normal healthy volunteers, it appears that the T-2525 is excreted from the kidneys not only into the glomerular filtration but also partly through renal tubules.

Adult↗
PubMed1985

Statistical mechanics of DNA topoisomers. The helical worm-like chain.

Recent experimental data of Shore & Baldwin (1983b) and of Horowitz & Wang (1984) for the apparent twisting coefficient K, which determines the breadth of the Gaussian distribution of DNA topoisomers with different linking numbers N, show that the product of K and nbp (the number of base-pairs) is nearly a constant for nbp approximately greater than 2000, but that it increases sharply with decreasing nbp for nbp approximately less than 2000. The main purpose of the present paper is to explain theoretically such behavior of K as a function of nbp. Thus the statistical mechanics of DNA topoisomers in general is developed on the basis of a twisted worm-like chain, i.e. a special case of the helical worm-like chain. The previous treatments of the N-dependent ring-closure probability, i.e. the distribution of N, which are valid only for small chain length L, are extended to the range of larger L. The variance of N is then shown to be exactly the sum of those of the writhe Wr and the twist Tw. For small values of L, the distribution of Wr is not Gaussian, and its variance or moment (Wr2) increases rather steeply with increasing L. With these and known Monte Carlo results for freely jointed chains, an empirical interpolation formula for (Wr2) is also constructed to be valid for all values of L. It predicts that (Wr2)/L increases monotonically, with increasing L to its coil-limiting value. On the other hand, the distribution of N is actually Gaussian in the practical range of N for all values of L. The conditional distribution of Wr with N fixed is also evaluated. Finally, K is expressed in terms of the torsional constant C, the stiffness parameter lambda-1 (which is equal to the Kuhn segment length and twice the persistence length for this special case), and (Wr2). The derived equation predicts that nbpK decreases monotonically to its coil-limiting value with increasing nbp. This decrease arises from the fluctuation in Wr and its neglect leads to an underestimate of C by 7 to 10%, even for short DNA with nbp approximately equal to 200. From an analysis of the experimental data of the two groups, the estimates of C = 3.1 to 3.2 X 10(-19) erg cm and lambda-1 = 1000 to 1200 A are obtained.

DNA↗
PubMed1985

Structural analysis of the gene coding for hepatitis B virus surface antigen and its product.

The entire genome of hepatitis B virus (subtype adr) has been cloned into pBR322. The clones could be classified into at least seven groups by their restriction endonuclease cleavage maps. The nucleotide sequences of the hepatitis B surface antigen (HBsAg)-coding regions for five clones were determined and compared with published sequences of the HBsAg gene including those of adw, ayw, adyw and adr. The 13 available versions of the amino acid sequence of the polypeptide, predicted from the nucleotide sequences, were analysed in terms of the established specificities of the HBsAg, including the four subtypes. The analysis indicated that a relatively hydrophilic region of the HBsAg protein, spanning amino acid residues 110 to 160, specifies the major (w) and (r) subtype system. The (w/r) subtype appears to depend on changes in one or more variable amino acids at positions 47, 110, 113, 126 and 160 of the HBsAg polypeptide.

Amino Acid Sequence↗
PubMed1985

Inhibitory effect of cephalosporins on gamma-aminobutyric acid receptor binding in rat synaptic membranes.

Cephalosporins inhibited gamma-aminobutyric acid receptor binding in a concentration-dependent manner in vitro. Scatchard analysis revealed that cefazolin decreased the binding capacity but did not change the affinity of the receptor. It is suggested that this inhibition of gamma-aminobutyric acid receptor binding may be involved in the induction of convulsions by cephalosporins.

Animals↗
PubMed1985

[Clinical study of ceftizoxime suppositories in acute suppurative otitis media in children and tissue concentration of ceftizoxime in the palatine tonsil after administration of ceftizoxime suppositories].

The newly developed ceftizoxime rectal suppository (CZX-S) contains 125 mg or 250 mg ceftizoxime (CZX) in potency. From the laboratory and clinical studies on CZX-S, the following results were obtained. Concentration of CZX in serum and palatine tonsil when 250 mg of CZX-S was rectally administered reached the peak level rapidly. The serum levels were 9.39 micrograms/ml in 30 minutes, 6.00 micrograms/ml in 45 minutes, 4.55 micrograms/ml in 60 minutes, 3.87 micrograms/ml in 90 minutes and 2.65 micrograms/ml in 120 minutes. The palatine tonsil levels were 2.73 micrograms/g in 30 minutes, 1.83 micrograms/g in 45 minutes, 1.54 micrograms/g in 60 minutes, 0.99 micrograms/g in 90 minutes and 0.74 micrograms/g in 120 minutes. About 30% of serum concentrations were distributed into palatine tonsil. CZX-S was administered at a daily dose of 375 mg or 750 mg divided 3 times for 4 approximately 9 days in 19 cases of acute suppurative otitis media of children. The overall clinical effect was excellent in 7 cases, good in 7 cases, fair in 2 cases and poor in 3 cases. The effectiveness rate was 73.7%. No side effects were observed in any cases.

Bacteria↗
PubMed1985

Cefmetazole: clinical evaluation of efficacy and safety in Japan.

During the period February 1980-March 1982, clinical evaluation was carried out on 23,855 cases given cefmetazole (CMZ) in 3,916 medical treatment centres in Japan. The drug was found to have superior efficacy and to be of value for all age groups, ranging from infants and small children to the elderly, in infections due to Gram-positive cocci, Gram-negative bacilli and anaerobic bacteria sensitive to this drug. Experiments were also conducted to elucidate the mechanism of development of the disulfiram-like reaction found in cephems with a methyltetrazolylthiomethyl group at the 3 position, i.e., cefmetozole (CMZ), cefoperazone (CPZ) and latamoxef (LMOX). These experiments provided clear evidence that the reaction is due to a rise in the blood concentration of acetaldehyde, as a result of inhibition of acetaldehyde dehydrogenase activity caused by these cephems. The extent of increase in the blood concentration of AcH is proportional to the urinary excretion rate of mercaptomethyltetrazole (Me-TZ), being in the order CPZ greater than LMOX greater than CMZ. This order is believed to be due to the extent of distribution in bile by various antibiotics and to their stability in the tissue fluids.

Adolescent↗
PubMed1985

[Studies of isolated organisms from otorhinolaryngological infections and their susceptibilities to macrolide antibiotics].

To study current situation of pathogenic bacteria and their drug resistance to macrolide antibiotics in the otorhinolaryngological infections, 609 strains diagnosed as pathogen derived from 463 patients were collected from cohospitals or institutions during the period of 1980-1983. The results obtained were as follows: Gram-positive cocci (GPC) was dominant (410 strains) and major species were S. aureus (135 strains), S. pneumoniae (81 strains), S. epidermidis (68 strains) and S. pyogenes (65 strains). In Gram-negative bacteria giving 147 strains and 43 strains, of anaerobes prevailing species were H. influenzae, P. aeruginosa and Peptostreptococcus spp. Representative species in the diseases were S. aureus (26.6%), S. epidermidis (24.5%), and P. aeruginosa (12.8%) in acute otitis media, S. aureus (34.4%), S. epidermidis (17.7%) and P. aeruginosa (14.6%) in acute exacerbation of chronic otitis media, S. epidermidis (17.0%), S. aureus (16.1%) and H. influenzae (13.4%) in acute paranasal sinusitis, S. pyogenes (29.1%), S. pneumoniae (19.6%) and S. aureus (15.1%) in acute tonsillitis. Although most of isolates were susceptible to macrolides, 62 resistant strains to macrolides were found in 501 strains and the resistant rates were 26.7% in S. aureus, 23.1% in S. epidermidis and 6.5% in S. pyogenes. The resistant pattern was somewhat different against each macrolides, resistant strains giving over 100 micrograms/ml in MIC were 55/62 in erythromycin, 35/62 in josamycin and midecamycin and 7/62 in TMS-19-Q, a new macrolide.

Bacteria↗
PubMed1985

Rapid clearance of iodine-131 MIBG from the heart and liver of patients with adrenergic dysfunction and pheochromocytoma.

Iodine-131 MIBG, a radiolabeled adrenergic neuron-blocking agent, decreased rapidly from the heart and liver of patients with adrenergic dysfunction (n = 3) and pheochromocytoma (n = 2) when compared with eight controls. The 4-hr activity expressed as percentages (mean +/- s.d.) of the 20-min counts were as follows: 80 +/- 3.0% in the controls compared with 60 +/- 7.6% in the patients over the heart (p less than 0.01) and 79 +/- 3.2% in the controls compared with 51 +/- 17% in the patients over the liver (p less than 0.02). However, there was no significant difference in the rate of [131I]MIBG decrease in these organs between controls and patients in the intervals subsequent to 4 hr (p greater than 0.05). These findings suggest that adrenergic neuronal uptake of [131I]MIBG in these organs is smaller in the patients than in the controls. Measurements of time-activity relationships of radioiodinated MIBG may be useful for assessment of adrenergic function of these organs and thus of generalized disorders of adrenergic innervation.

3-Iodobenzylguanidine↗
PubMed1985

[Clinical study on unmodified intravenous dried ion-exchange resin treated human normal immunoglobulin, SM-4300].

Unmodified intravenous dried ion-exchange resin treated human normal immunoglobulin, SM-4300, was administered to 4 patients with severely intractable infectious diseases. Obvious antipyretic effect, opsonic effect and and investigational findings on healing are not observed. However, in both subjective and objective clinical effects, we obtained the following test results, that is, 1 case of effective and 2 cases of rather effective. No side effects by SM-4300 were observed.

Adult↗