The authors studied aminobenzylpenicillin (AB-PC) basically and clinically and obtained the following results: 1) Susceptibilities of Staph. aureus and E. coli, both isolated from vagina of pregnant women, to aminobenzylpenicillin were studied by means of 3 concentrations disc method and the former showed the susceptibility in 62. 5% and the latter in 53. 4%. 2) MIC of AB PC for the maintained Staph. aureus in vitro was O. 625∼5. 0 mcg/ml. 3) The concentrations of the transferred AB PC in various kinds of body fluid were similar to those of other antibiotics. 4) The transfer into the circulatory blood of the new born infants through the lactation in the maternal intramuscular injection of 250 m g AB- PC was investigated but the level was almost inmeasurable. 5) Good results were obtain ed in the treatment of infection in obstetric and gynecologic fields by the oral administration or the intramuscular injection in doses of 1∼2 g daily. 6) Good results were obtained for the prophylaxis against the postoperative urinary tract infection in cancer of the cervix by instilling 100 mg of AB PC into the vesical bladder for each time. 7) No specific side effect was observed in all cases.

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Both laboratory and clinical evaluation of aminobenzyl penicillin(AB-PC), a recently introduced semisynthetic penicillin, has been pursued to determine its spectrum of antimicrobial activity, its potency, blood and tissue levels following intramuscular or oral administration, and its usefulness in the treatment of urinary tract infections in gynecology and obstetrics.
1) The results of assays for its growth-inhibitory concentrations toward Staphylococci and gramnegative bacilli stress its profound antiba. cterial activity against Coliform group bacilli.
2) Oral AB-PC has proven to be promptly absorbed from the intestine and hence to yield high tissue concentrations.
3) Of 29 patients with urinary tract infections (i. e. acute cystitis and postoperative urinary tract infections) who were treated, 24 exhibited satisfactory therapeutic responses to the agent. Its efficaciousness was particularly remarkable with E. coli infections. Clinical usefulness of AB-PC in urinary tract infections therefore is unquestioned.

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Newborn rats, Wistar strain, from one to seven days of age, were injected intraperitoneally with chloramphenicol (CP), tetracycline (TC), streptomycin (SM) and the bone marrow, liver, spleen were examined histologically. The following changes were noted in the bone marrow; marked decrease of the megakaryocyte and mitosis either by administration of large dose (ten times of therapeutic dose for the newborn infant) or by medium dose (seven times of the therapeutic dose) or consecutive administration for five days in small dose (1. 7 times of the therapeutic dose). TC or SM showed no effect on the bone marrow either by large or small doses. There was no remarkable change in the liver or spleen by CP, TC or SM. From the above, the following method was demonstrated to be suitable for assessment of toxicity of antibiotics to the hematopoietic organ; observation of numerical change of the megakaryocyte and mitosis of the bone marrow of newborn rat after administration of the antibiotics once with ten times in dosage or 1. 7 times (1. 5∼2. 0 times) for five days.

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Reproducibility of drug-sensitivities, determined with the one-and the three-concentration disks were compared each other with reference to the values of the agar plate streak method. Experimental results revealed that fluctuations were relatively small if the results were expressed as _??_, _??_-, + and in the one-concentration disk method, but that fluctuations were considerably great when the s ize of the inhibitory zone was expressed in terms of the sensitivity value by the agar plate dilution method.
After these results, the author attempted simplification of the procedures of sensitivity determination, and devised a new method, in which the intermediate concentration of the three concentration disks is used singly, and the result is determined as “sensitive” when the diameter of the inhibitory zone is greater than 15 mm, and as “resistant” when it is smaller than 15 mm, under the condition of constant thickness of the agar plate. According to this expression of the results, “very sensitive” and some of “moderately sensitive” by the three concentration disks are included in the sphere of, “sensitive”, and “slightly sensitive”, “resistant” and some of “moderately sensitive” in the sphere of “resistant”

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Resistance to mitomycin C in YOSHIDA sarcoma was studied in comparison with alkylating agents that is endoxan and busulfan. Mitomycin C resista n t sarcoma (MMC-R, 0. 5 mg/kg s. c. ) was established at the 2 nd generation by one generation of MMC treatment. Endoxan resistant sarcoma (EX-R, 5 mg/kg i. p. ) was established at the 12th generation and busulfan resistant sarcoma (BUS-R, 10 mg/kg i. p. ) was established at the 13 th generation. MM C -R showed cross resistance to endoxan (5 mg/kg, 10 mg/kg, 20 mg/kg i. p. ) and busulfan (10 mg/kg, 20 mg/kg i. p. ). EX-R and BUR-R showed cross resistance to BUS or EX respectively, however the both lines did not show cross resistance to mitomycin C. These results might indicate that mitom ycin C possessed a different action mechanism from alkylating agents. Chr o mosome studies on original and MMC-R sarcom showed differences in karyotype between the two lines. In 1-13-thymidine radioautograph studies, MMC-R showed longer generation time than that of the original sarcoma. Experim e nts on uptake of mitomycin C by sarcoma cells were carried out in vitro. Rate of uptake of mitomycin C was measured by the decrease of MMC from incubation medium and by MIYAMURA'S bioassay using cell homogenate. No notable difference was observed between original and MMC-R sarcoma. Non protein sulfhydryl group (SH) was measured by a modified method of BEUTLER et al. Amount of SH in original and MMC-R sarcoma cells was not significantly different each other.

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In case of antibiotic therapy, if we could objectively know the exact degree of the disease, it is useful for judging the effect of the antibiotics and moreover for comparing the antibiotics with others.
We report the result, which we have tried to express in figures, about pericoronitis, one o f the most frequent disease in the domaine of oral surgery.

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