Estudio toxicológico y teratogénico del extracto metanólico de cinnamomun zeylanicum (canela) / Toxicológico and teratogénico study of the metanólico extract of cinnamomun zeylanicum (cinnamon)

Se realizó el estudio fitoquímico, toxicológico agudo y citotóxico del cinnamomum zeylanicum (canela). Para la determinación de la DL50 se utilizaron 30 ratones albinos, cuyos pesos oscilaron entre 25 y 30 gr., siguiendo el método de Probits. Igualmente se determinó la concentración letal media (CL-50) en artemia salina. La actividad citotóxica y teratogénica fue evaluada en huevos de Tetrapygus Níger (erizo de mar). Nos permite concluir, siguiendo los criterios de William, que el extracto metanólico de la canela es ligeramente tóxico y posee efecto citotóxico frente al erizo de mar, no evidenciándose efecto teratogénico, a las dosis empleadas.

We have performed a Phytochemic. Toxicologic and Cytotoxic study, of Cinamomum zeylanicum (canela) in laboratory. We have determinated the letal 50-doses (DLSO) in mice, the letal middle concentration (CL_50) in Artemia salina and the cytotoxic and teratogenic effect on Tetrapygus niger eggs (sea Hedgehog). We may conclude following the William Criterions that the metanolic extract of canela is lightly toxic and it has cytotoxic effects on sea Hedgehog at the doses studied.

Rationale behind high-dose amoxicillin therapy for acute otitis media due to penicillin-nonsusceptible pneumococci: support from in vitro pharmacodynamic studies.

To evaluate whether increased doses of amoxicillin should be used to treat acute pneumococcal otitis media, an in vitro pharmacokinetic model was used to evaluate the killing of pneumococci by amoxicillin when middle ear pharmacokinetics were simulated. Logarithmic-phase cultures were exposed to peak concentrations of 3, 6, and 9 microg of amoxicillin per ml every 12 h, and an elimination half-life of 1.6 h was simulated. Changes in viable bacterial counts were measured over 36 h. All three doses rapidly decreased the viable bacterial counts of penicillin-susceptible strains below the 10-CFU/ml limit of detection by 6 to 10 h and maintained counts below this limit through 36 h. The 3-microg/ml peak dose was much less effective against two of three strains with intermediate penicillin resistance and all three penicillin-resistant strains, with bacterial counts approaching those in drug-free control cultures by 12 h. The 6-microg/ml peak dose completely eliminated two of three strains with intermediate penicillin resistance and maintained viable counts of the other nonsusceptible strains at 1.5 to 2 logs below the initial inoculum through 36 h. The 9-microg/ml peak dose was most effective, completely eliminating all three strains with intermediate penicillin resistance and maintaining the viable counts of the resistant strains at 3 to 4 logs below the original inoculum. The pharmacodynamics observed in this study suggest that peak concentrations of amoxicillin of 6 to 9 microg/ml may be sufficient for the elimination of penicillin-nonsusceptible pneumococcal strains causing otitis media, especially those with intermediate resistance to amoxicillin. In vivo pharmacokinetic studies are needed to determine if these levels can be achieved in middle ear fluid with amoxicillin at 70 to 90 mg/kg/day divided into two daily doses. If these levels are reliably achieved, then clinical studies are warranted.

Multiply-resistant pneumococcus: therapeutic problems in the management of serious infections.

The control of penicillin-resistant pneumococci has become one of the more serious therapeutic challenges facing clinicians today. The occurrence and geographical coverage of these microorganisms have increased rapidly since they were first recognized in the late 1960s. They have now been reported from every continent, and in some regions can account for over 60% of the pneumococci isolated. An even greater concern is the propensity of penicillin-resistant pneumococci towards resistance to multiple antibiotics, including the cephalosporins and non-beta-lactam drugs. In areas where multiply-resistant strains are common, the therapeutic choices for the treatment of life-threatening infections may be limited to drugs which are either toxic for the patient or for which we are only beginning to gain clinical experience. As the importance of Streptococcus pneumoniae in meningitis continues to increase and multiply-resistant strains become more widespread and entrenched, it is essential that the search for more well-tolerated and effective treatment regimens continues. However, unless the effect of antibiotics on the selection of these resistant pathogens is addressed and a more judicious approach towards drug use is taken; this resistance problem will continue well into the future.