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Dive into the research topics where Hiroaki Omata is active.

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Featured researches published by Hiroaki Omata.


General Pharmacology-the Vascular System | 1990

Cephalexin concentrations in human serum, gingiva, and mandibular bone following a single oral administration

Yoshiaki Akimoto; Akio Uda; Hiroaki Omata; Jun Shibutani; Hitoshi Nishimura; Masamichi Komiya; Kenji Kaneko; Akira Fujii

1. Cephalexin concentrations in human serum, gingiva, and mandibular bone after a single oral administration of cephalexin (500 mg) were measured by the paper disc method. 2. The peak times of serum, gingiva, and mandibular bone were approximately 90, 120 and 120 min, respectively. 3. The peak concentrations of serum, gingiva, and mandibular bone were 10.58 micrograms/ml, 5.57 micrograms/g and 2.12 micrograms/g, respectively. 4. The concentration ratio of gingiva/serum and mandibular bone/serum peak time of serum were 0.47 and 0.18, respectively. 5. Cephalexin concentrations in gingiva and mandibular bond did not exceed the MIC80s for clinically isolated strains of Staphylococcus aureus spp., alpha-Streptococci and Peptostreptococcus spp.


General Pharmacology-the Vascular System | 1989

Josamycin concentrations in human dental granuloma after a single oral administration of josamycin

Akio Uda; Hiroaki Omata; Jun Shibutani; Hitoshi Nishimura; Masamichi Komiya; Yoshiaki Akimoto; Kenji Kaneko; Akira Fujii

1. Josamycin concentrations in human serum and dental granuloma after a single oral administration of josamycin (600 mg) were assayed by an agar diffusion (paper disc) method. 2. The mean peak josamycin concentrations in serum and dental granuloma occurred at an identical time, approximately 90 min, and were 0.88 micrograms/ml and 1.61 micrograms/g, respectively. 3. The mean concentration ratio of dental granuloma to serum at the peak time was 2.24. 4. Josamycin concentration in dental granuloma at the peak time exceeded MIC80 for clinically isolated strains of Streptococcus group A, Peptostreptococcus spp., and Bacteroides spp.


General Pharmacology-the Vascular System | 1996

Cefaclor concentration in pus from abscess caused by odontogenic infection after a single oral administration

Yoshiaki Akimoto; Hitoshi Nishimura; Hiroaki Omata; Jun Shibutani; Kenji Kaneko; Tomonori Kawana; Takashi Kaneda; Hirotsugu Yamamoto; Akira Fujii

1. Cefaclor concentrations in serum and pus from abscess of odontogenic infection after a single oral administration of 500-mg cefaclor were assayed and pus concentrations were compared with minimum inhibitory concentration (MIC) of oral streptococci isolated from odontogenic infection. 2. The mean peak concentrations in serum and pus were found at identical times, 1.5 hr after administration, which were 7.22 and 0.72 micrograms/ml, respectively. 3. The mean ratio of pus:serum concentration at the peak time was 0.10. 4. Most cefaclor concentrations in pus at the peak time (seven of nine cases) exceeded the MIC for 90% of oral streptococci (0.5 micrograms/ml).


General Pharmacology-the Vascular System | 1986

Ampicillin concentrations in human serum and periodontal membrane following a single oral administration of talampicillin

Yoshiaki Akimoto; Akio Uda; Hiroaki Omata; Hitoshi Nishimura; Masamichi Komiya; Kenji Kaneko; Akira Fujii; Toyoyuki Tamura

1. Ampicillin concentrations in human serum and periodontal membrane after a single oral administration of talampicillin (500 mg) were assayed by the agar diffusion (paper disc) method. 2. The peak times of serum and periodontal membrane were identical, being 150 min after administration. 3. The peak concentrations of serum and periodontal membrane were 7.81 micrograms/ml and 4.11 micrograms/g, respectively. 4. The mean ratio of periodontal membrane to serum concentration at the peak time was 0.53.


General Pharmacology-the Vascular System | 1994

Amoxicillin concentration in pus from abscess caused by odontogenic infection

Yoshiaki Akimoto; Yoshiko Mochizuki; Akio Uda; Hiroaki Omata; Jun Shibutani; Hitoshi Nishimura; Masamichi Komiya; Kenju Kaneko; Akira Fujii

1. Amoxicillin concentration in pus from odontogenic infection was assayed and the concentrations were compared with MIC (minimum inhibitory concentration) of alpha-hemolytic streptococci isolated from odontogenic infection. 2. Measurable amoxicillin concentrations in serum and pus were found in all instances (n = 16). 3. The mean peak concentrations in serum and pus were found at identical times, 1.5 hr after administration, which were 5.92 and 0.90 micrograms/ml, respectively. 4. The mean concentration ratio of pus/serum at the peak time was 0.15. 5. All amoxicillin concentrations in pus at the peak time exceeded the MIC for 90% of alpha-hemolytic streptococci (0.25 micrograms/ml).


General Pharmacology-the Vascular System | 1993

Josamycin concentrations in radicular cysts following a single oral administration

Yoshiaki Akimoto; Yoshiko Mochizuki; Akio Uda; Hiroaki Omata; Sumio Saito; Kenji Kaneko; Akira Fujii; Hirotsugu Yamamoto

1. Josamycin concentrations in cyst wall (wall) and cyst fluid (fluid) of radicular cyst and serum following a single oral administration of josamycin (600 mg) were assayed by a paper disk method. 2. The mean peak josamycin concentrations in wall, fluid and serum occurred at 1.5, 2 and 1.5 hr, respectively, and were 1.33 micrograms/g, 0.53 and 0.74 micrograms/ml, respectively. 3. The mean concentration ratios of wall/serum, fluid/serum and fluid/wall at the peak times (1.5, 2 and 2 hr) were 1.80, 0.64 and 0.42, respectively. 4. Josamycin concentrations in wall and fluid at the peak time exceeded MIC for 80% for clinically isolated strains of alpha-hemolytic Streptococci.


General Pharmacology-the Vascular System | 1994

Cephalexin concentrations in radicular granuloma following a single oral administration of 250- or 500-mg cephalexin

Yoshiaki Akimoto; Akio Uda; Hiroaki Omata; Jun Shibutani; Hitoshi Nishimura; Masamichi Komiya; Tomonori Kawana; Kenji Kaneko; Akira Fujii; Takashi Kaneda; Hirotsugu Yamamoto

1. Cephalexin concentrations in radicular granuloma and serum following a single oral administration of 250- or 500-mg cephalexin were measured by a paper disk method. 2. The highest concentration of cephalexin in radicular granuloma following administration of 250-mg cephalexin to nonfasting patients was observed at 2 hr, and was 1.62 micrograms/g. The mean cephalexin concentration ratio of radicular granuloma/serum at 2 hr was 0.35. 3. The highest concentrations of cephalexin in radicular granuloma following administration of 500-mg cephalexin to nonfasting and fasting patients occurred at 2 and 1.5 hr, and was 3.35 and 3.42 micrograms/g, respectively. Mean cephalexin concentration ratios of radicular granuloma/serum at 2 and 1.5 hr were 0.32 and 0.30, respectively. 4. All mean cephalexin concentrations in radicular granuloma following administration of 500-mg cephalexin to both fasting and nonfasting patients exceeded MIC for 90% (2 micrograms/ml) of clinically isolated strains of alpha-hemolytic streptococci. However, those concentrations obtained by 250-mg cephalexin did not exceed it.


General Pharmacology-the Vascular System | 1991

Ampicillin concentrations in human oral tissues following a single oral administration of lenampicillin

Yoshiaki Akimoto; Yoshiko Mochizuki; Akio Uda; Hiroaki Omata; Jun Shibutani; Kenji Kaneko; Junichi Yamane; Akira Fujii; Hirotsugu Yamamoto

1. Ampicillin concentrations in serum (n = 20), gingiva (n = 12), jawbone (n = 13), dental follicle (n = 12), radicular granuloma (n = 2) and radicular cyst (n = 2) were measured in specimens obtained during 0.5-2.5 hr after a single oral administration of lenampicillin (equivalent to 500 mg of ampicillin). 2. Measurable ampicillin concentrations were found in all serum and tissues. 3. Ampicillin concentrations in serum and tissues except for some gingiva and jawbone exceeded MIC for 90% of clinically isolated strains of alpha-hemolytic Streptococci. 4. Ampicillin concentrations in gingiva and jawbone were below the MIC for 90% in 2 out of 12 and 4 out of 13 specimens, respectively.


General Pharmacology-the Vascular System | 1998

Cefaclor Concentration in Radicular Granuloma after a Single Oral Administration

Yoshiaki Akimoto; Makiko Ikeda; Hiroaki Omata; Jun Shibutani; Akira Fujii; Takashi Kaneda; Hirotsugu Yamamoto; Tsuyoshi Takato

1. Cefaclor concentrations in radicular granuloma and serum in nonfasting patients after a single oral administration of 500-mg cefaclor were assayed. 2. The mean peak concentrations in radicular granuloma and serum were 2.57 mcg/g and 7.41 mcg/ ml, respectively. The mean ratio of granuloma/serum concentration at the peak time was 0.35. 3. All cefaclor concentrations in radicular granuloma at the peak time exceeded the minimal inhibitory concentration for 90% of oral streptococci (1 mcg/ml) isolated from odontogenic infection.


The Journal of Nihon University School of Dentistry | 1991

Gingival Hyperplasia Induced by Nifedipine

Yoshiaki Akimoto; Shigeo Tanaka; Hiroaki Omata; Jun Shibutani; Yuri Nakano; Kenji Kaneko; Tomonori Kawana; Hiroshi Teshigawara; Sumi Nakao; Akira Fujii; Hirotsugu Yamamoto; Hiroshi Mochizuki

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