Antimicrobial susceptibility of air-dispersed microorganisms in dental settings.

To determine the number and the susceptibility of microorganisms collected in a clinical environment against the antimicrobial agents used commonly in dentistry, petri dishes containing trypticase soy agar were exposed to air in different sites of a multi-chair dental clinic before, during, and after multiple clinical procedures and incubated for 24 hours under aerobic conditions. Colonies were identified by Gram stain technique and biochemical tests. Commercial paper disks containing widely prescribed antimicrobial agents (beta-lactams, macrolides, and clindamycin) were used to perform the antimicrobial susceptibility tests. The groups (colony forming units = cfu/m2/min) were submitted to the Kruskal-Wallis test (alpha = 5.0%), considering different clinical situations and environmental sites. During clinical procedures, the number of microorganisms increased (p < 0.05). This study highlights the need for established strategies to prevent resistant bacterial strains from emerging in dental settings.

Bioassay of amoxicillin in rats.

Few reports are available about tissue concentration of amoxicillin. The techniques used to measure tissue concentration usually require rupture and are expensive. The objective of the present study is to assess the utility of an animal model to predict tissue concentration of amoxicillin using induced granulomatous tissue. We used 160 rats with four polyurethane sponges previously implanted in their backs. At 7, 14, 21 and 28 d after sponge introduction, groups of eight animals each received 3.5, 7.0, 40.0 or 80.0 mg/kg of amoxicillin (p.o.) or 1 ml of 0.9% NaCl solution (control group). One hour after drug administration, 10 microl of serum and granulomatous tissue were obtained. Tissue and serum were placed on different plates containing Mueller Hinton agar inoculated with 10(8) cfu (colony forming unit) of Staphylococcus aureus (ATCC 25923), and the diameters of the inhibition zones were measured after 18 h of incubation. Analysis of variance showed no statistically significant differences (p>0.05) among time periods for the same dose of amoxicillin. These results suggest that the pharmacokinetics of amoxicillin did not change in relation to the development of granulomatous tissue; therefore this method is valid to measure the tissue concentration of amoxicillin.

Effect of H1 and H2 receptor antagonists on the serum activity of gamma-glutamyltransferase during liver regeneration after partial hepatectomy in rats.

Chronic administration of a low dose of the histamine H1 receptor antagonist terfenadine (2 mg/kg/day) induced an increase in gamma-glutamyltransferase serum activity in rats, 360 h after partial hepatectomy while the enzymatic activity appeared not to be affected during liver regeneration following treatment with the histamine H2 receptor antagonist cimetidine (20 mg/kg/day).

Involvement of the central nervous system in the salivary secretion induced by pilocarpine in rats.

The effect of rats of an anteroventral third ventricle (AV3V) electrolytic lesion on salivary secretion induced by intraperitoneal (i.p.) or intracerebroventricular (i.c.v.) injection of a cholinergic agonist (pilocarpine) was investigated. Sham- or AV3V-lesioned rats anesthetized with urethane and with a stainless steel cannula implanted into the lateral ventricle (LV) were used. The amount of salivary secretion was studied over a seven-minute period after i.c.v. or i.p. injection of pilocarpine. In sham-operated rats, i.p. injection of pilocarpine (1 mg/kg b.w.) (after 6 h, 2, 7, and 15 days) produced salivary secretion (486 +/- 21, 778 +/- 85, 630 +/- 50, and 560 +/- 55 mg/7 min, respectively). This effect was reduced 6 h, 2, and 7 days after an AV3V lesion (142 +/- 22, 113 +/- 32, and 290 +/- 62 mg/7 min, respectively), but not 15 days after an AV3V lesion (516 +/- 19 mg/7 min). I.c.v. injection of pilocarpine (120 micrograms in 1 microL), in sham-operated rats after 6 h, 2, 7, and 15 days also produced salivary secretion (443 +/- 20, 417 +/- 81, 496 +/- 14, and 427 +/- 47 mg/7 min, respectively). The effects of i.c.v. pilocarpine were also reduced 6 h, 2, and 7 days after an AV3V lesion (143 +/- 19, 273 +/- 14, and 322 +/- 17 mg/7 min, respectively), but not after 15 days (450 +/- 28 mg/7 min). The results demonstrate that the central nervous system, and particularly the AV3V region, is important for the effect of pilocarpine on salivary secretion in rats.(ABSTRACT TRUNCATED AT 250 WORDS)

[Prilocaine as an hypotensive ocular agent (author's transl)]. / Estudo da ação da prilocaína como agente hipotensor ocular.

The purpose of the present investigation was to determine the action of prilocaine as hypotensive ocular agent. Prilocaine in doses of 2.5 mg/kg, 5 mg/kg and 10 mg/kg was administered intravenously in dogs anesthetized with sodium pentobarbital (30 mg/kg). The experiments show that prilocaine when used i.v. in doses of 2.5 mg/kg and 5 mg/kg causes ocular hypotension in dogs, whereas doses of 10 mg/kg i.v. produce this effect only when artificial respiration is employed, thus preventing the increase of the pCO2 in the blood.