Biomedical subjects

H Akamatsu

Publications and source records attributed to H Akamatsu.

152 records · Page 9Linked to original sources

PubMedDate not supplied

Clinical evaluation of roxithromycin in patients with acne.

On the basis of reports that erythromycin is effective in the treatment of acne, we investigated whether roxithromycin (ROM), a new derivative of erythromycin, might also be effective in treating acne. Roxithromycin was administered to 30 patients with acne for 8 weeks. General improvement was assessed 8 weeks after the initiation of the therapy with a six-graded scale as follows; 1: good improvement, 2: moderate improvement, 3: slight improvement, 4: no change, 5: worsening, and 6: no assessment. The percentage of good or moderate improvement was 73.3%, and that of good improvement alone was 20.0%. Our results suggest that ROM is effective in the treatment of acne.

Acne Vulgaris↗

PubMedDate not supplied

Enhanced effect of clarithromycin on neutrophil function in vitro.

An in vitro study was carried out to investigate the effect of clarithromycin, a new oral macrolide, on neutrophil reactive oxygen species generation and chemotaxis. It was found that neutrophil-generated O2-, H2O2 and OH. levels were significantly increased by clarithromycin at concentrations of 50 micrograms/ml (P < 0.05). The drug also significantly increased chemotaxis (P < 0.05). These results indicate that clarithromycin may enhance the activation of neutrophils in vivo.

Anti-Bacterial Agents↗

PubMedDate not supplied

Effect of pyridone carboxylic acid anti-microbials on the generation of reactive oxygen species in vitro.

The effects of ofloxacin, ciprofloxacin and balofloxacin on the reactive oxygen species (ROS) levels generated by human neutrophils was examined in vitro; ROS generated in a cell-free, xanthine-xanthine oxidase system was also assessed. The species investigated were superoxide radical anion (O2-), hydrogen peroxide (H2O2) and hydroxyl radical (OH*). Both ofloxacin and ciprofloxacin markedly decreased the levels of O2-, H2O2 and OH* generated by human neutrophils. On the other hand, these drugs did not affect any of the ROS examined in the xanthine-xanthine oxidase system. Balofloxacin showed no significant effect on ROS generated by either system. The present study indicates that ofloxacin and ciprofloxacin may exert an anti-inflammatory action by reducing the potent ROS species excessively generated by neutrophils at the sites of inflammation.

Anti-Infective Agents↗

PubMedDate not supplied

Effect of keigai-rengyo-to, a Japanese kampo medicine, on neutrophil functions: a possible mechanism of action of keigai-rengyo-to in acne.

On the basis of recent reports that keigai-rengyo-to (TJ-50), an oral Japanese Kampo (herb) medicine, is clinically effective in treating acne, and that tetracyclines are effective against acne by acting directly as an antioxidant on infiltrated neutrophils, we investigated the effect of TJ-50 on the generation of reactive oxygen species (ROS), using human neutrophils and a cell-free, xanthine-xanthine oxidase system. The species investigated were superoxide radical anion (O2-), hydrogen peroxide (H2O2), and hydroxyl radical (OH.). In addition, neutrophil chemotaxis, phagocytosis and calcium concentration, [Ca2+]i in neutrophils were also assessed. TJ-50 significantly decreased neutrophil-generated O2-, H2O2 and OH. in a dose-dependent manner. Three kinds of ROS generated in the cell-free system were also reduced in the presence of TJ-50. On the other hand, the medicine did not markedly affect neutrophil chemotaxis, phagocytosis or [Ca2+]i in neutrophils. Our results indicate that the clinical effectiveness of TJ-50 in the treatment of acne may be due partly to its antioxidant action on infiltrated neutrophils.

Acne Vulgaris↗

PubMedDate not supplied

Effects of roxithromycin on adhesion molecules expressed on endothelial cells of the dermal microvasculature.

The objective of the study was to investigate the pharmacological action of roxithromycin, an oral macrolide antibiotic. The effects of roxithromycin on the cytokine-induced expression of endothelial leukocyte adhesion molecule (E-selectin) and intracellular adhesion molecule (ICAM)-1 on endothelial cells of the dermal microvasculature were investigated in vitro using flow cytometry. Roxithromycin at a concentration of 0.5 microgram/ml, which is lower than the therapeutic plasma concentration (ordinary daily dose, 150-300 mg), significantly inhibited the expression of E-selectin and ICAM-1 on endothelial cells of the dermal microvasculature induced by tumour necrosis factor-alpha. We conclude that roxithromycin may exert its anti-inflammatory action by inhibition of the in vivo expression of adhesion molecules on dermal microvascular endothelial cells.

Anti-Bacterial Agents↗

PubMedDate not supplied

Concentration of roxithromycin in the lesions of acne vulgaris.

Roxithromycin, a macrolide antibiotic, is used in the treatment of acne vulgaris, although there have been no reports on its concentration in lesions when administered orally. We investigated the concentration of roxithromycin in acne vulgaris lesions in five patients who received 150 mg roxithromycin orally twice daily for 2 weeks. The mean concentration of roxithromycin in the lesions was 0.54 microgram/ml. These results suggest that roxithromycin accumulates at therapeutic levels in the pilosebaceous system.

Acne Vulgaris↗

PubMedDate not supplied

Atopic dermatitis-like symptoms in HR-1 hairless mice fed a diet low in magnesium and zinc.

We aimed to develop an animal model for atopic dermatitis. HR-1 hairless mice fed a diet with reduced magnesium and zinc levels were compared with mice fed a standard diet. Skin dryness and wrinkle-like changes, scratching behaviour, decreased skin water content, increased transepidermal water loss and raised blood immunoglobulin E levels were seen in the group receiving the reduced magnesium and zinc diet compared with control mice. There were no significant differences in body weight or the weight of the major organs between the two groups. Haematological examination in both groups was normal apart from increased immunoglobulin E levels in mice fed a reduced magnesium and zinc diet. These mice may be useful models of atopic dermatitis; preparation of the animals is not particularly time consuming, the reproducibility is 100%, and atopic dermatitis symptoms occur even in a specific pathogen-free environment.

Animal Feed↗

PubMedDate not supplied

The effect of fexofenadine on pruritus in a mouse model (HR-ADf) of atopic dermatitis.

Fexofenadine, a histamine H1-receptor antagonist, is approved for the treatment of pruritus associated with atopic dermatitis. The effects of fexofenadine on scratching behaviour, and plasma levels of histamine and eotaxin were assessed in a new model of atopic dermatitis. Mice fed a diet low in Mg2+ and Zn2+ (special diet S) were compared with mice on a normal diet (N) or diet S plus fexofenadine HCl for weeks 0-10 (S + F(0-10)), 0-5 (S + F(0-5)) or 6 - 10 (S + F(6-10)) (seven mice per group). Compared with group N, group S mice showed significantly greater scratching frequency, and plasma histamine and eotaxin concentrations; these three variables were significantly lower in group S + F(0-10) than in group S. Scratching frequency increased when fexofenadine was discontinued. Fexofenadine significantly reduced mast cell and eosinophil numbers. Histamine may be important in the pathological changes seen in this model of atopic dermatitis, suggesting that it might aid future development of antihistamines for the treatment of atopic dermatitis.

Animals↗