Shigekatsu Kawabata

Clinical and bacteriologic evaluation of OPC-7251 in patients with acne: A double-blind group comparison study versus cream base

Twenty-eight patients with acne were assigned to 4 weeks of treatment with OPC-7251 (a new fluoroquinolone derivative) 1% cream or the cream base in a double-blind manner to evaluate the antibacterial effect of the drug on resident bacteria in the hair follicles and to evaluate clinical response. Propionibacterium acnes was isolated from 21 of the 28 acne patients. When the number of P. acnes was compared before and after treatment, the posttreatment P. acnes count in the OPC-7251 1% cream group was significantly (p = 0.000) reduced compared with that in the cream base group. OPC-7251 1% cream was also significantly (p = 0.019) superior to the cream base in terms of clinical response. P. acnes and Staphylococcus epidermidis isolated from the acne lesions were selected for their susceptibility to various antibacterial agents. The minimal inhibitory concentration of OPC-7251 against P. acnes and S. epidermidis was 0.10 to 0.20 and 0.024 to 0.10 micrograms/ml, respectively, which indicates that the drug has a potent antibacterial effect.

Activity of Eight Fluoroquinolones against Both Methicillin-Susceptible and -Resistant Staphylococcus aureus Isolated from Skin Infections

The in vitro susceptibility of Staphylococcus aureus to eight fluoroquinolones, norfloxacin, ofloxacin, enoxacin, ciprofloxacin, lomefloxacin, tosufloxacin, sparfloxacin, and nadifloxacin was established by agar dilution tests, 71 isolates of methicillin‐susceptible (MSSA) and 74 isolates of ‐resistant S. aureus (MRSA) isolated from skin infections. Among all of the fluoroquinolones, nadifloxacin exhibited the lowest MIC for both MSSA and MRSA. In addition, there were no resistant S. aureus, neither MSSA and MRSA, to nadifloxacin. With the exception of nadifloxacin, the incidence of MRSA resistant to fluoroquinolones has gradually increased in recent years. Over half of the MRSA strains were resistant to norfloxacin, ofloxacin, enoxacin, ciprofloxacin, and lomefloxacin.

In Vitro Activity of Nadifloxacin against both Methicillin-Susceptible and -Resistant Clinical Isolates of Staphylococcus aureus from Patients with Skin Infections

The most common causative pathogen in patients with skin infections is Staphylococcus aureusPl The prevalence of methicillin-resistant S. au reus (MRSA), which causes serious infections in immunocompromised patients, has increased in recent years at the Department of Dermatology at Kansai Medical UniversityPl In addition, the incidence of multiply-resistant strains of S. au reus has been increasing. Fluoroquinolones are a group of oral antimicrobial agents with broad spectrum activity, including methicillin-susceptible Staphylococcus species (MSSA) and some MRSA strains. The object of this study was to determine the in vitro susceptibility of MSSA and MRSA clinical isolates from patients with skin infections to nadifloxacin and 7 other fluoroquinolones. Nadifloxacin is a new fluoroquinolone that has been developed for use as a topical acne medicationp.41

Effects of adenosine 5′-monophosphate on epidermal turnover

The structure and function of the epidermis is maintained by cell renewal based on epidermal turnover. Epidermal turnover is delayed by aging, and it is thought that the delay of the epidermal turnover is a cause of aging alternation of skin. The epidermal turnover is related to the energy metabolism of epidermal basal cells. Adenosine 5′-triphosphate (ATP) is needed for cell renewal: cell division, and adenosine 5′-monophosphate (AMP) increases the amount of intracellular ATP. These findings suggest that AMP accelerates the epidermal turnover delayed by aging. This study investigated whether AMP and adenosine 5′-monophosphate disodium salt (AMP2Na) accelerates the epidermal turnover. An effect of AMP2Na on cell proliferation was examined by our counting of keratinocytes. An effect of AMP2Na on cell cycle was examined by our counting of basal cells in DNA synthetic period of hairless rats. The effects of AMP2Na (or AMP) on the epidermal turnover were examined by our measuring stratum corneum transit time by use of guinea pigs, and by our measuring stratum corneum surface area by use of hairless rats and in a clinical pharmacological study. The AMP2Na showed two different profiles on the proliferation of primary cultured keratinocytes. At a low concentration it induced cell growth, whereas at a high concentration it inhibited cell growth. The number of basal cells in the DNA synthetic period of AMP2Na was significantly higher than that of the vehicle in hairless rats. The stratum corneum transit time of AMP2Na was significantly shorter than that of the vehicle in guinea pigs. The corneocyte surface area of emulsion containing AMP2Na was significantly smaller than that of the vehicle in volunteers. We conclude that AMP promotes the cell proliferation and the cell cycle progression of epidermal basal cells and accelerates epidermal turnover safely. In addition, AMP is useful for skin rejuvenation in dermatology and aesthetic dermatology.