Empleo de nuevas tecnologías para la solución de un problema sobre el concepto de trabajo: bombear líquido de un tanque cilíndrico

El propósito de este proyecto es el de contribuir a un mejor conocimiento de la teoría de trabajo mecánico, especialmente para la parte del cálculo de áreas bajo una curva, hemos podido observar que en el transcurso de varios años del tratamiento de este tema, que este tipo de concepto presentan problemas para el estudiante, que es, generalmente, el de visualizar el fenómeno físico, a partir del modelo matemático, para ello, se ha tratado con ejemplos de clarificar la teoría sin incidir demasiado en la complejidad matemática, dado que en estos tiempos de software de simulación y amplia información (Internet), el tener el concepto claro es más importante que el resolver problemas mecánicamente, hay que mencionar a los estudiantes que en la vida profesional, la capacidad de resolver problemas entendiendo las causas de estos, es importante, que tratar de aplicar recetas que no se adecúen al problema que uno enfrenta y hagan que la situación se complique; en la vida de estudiante, esto último equivale a resolver problemas tipos, de memoria o mecánicamente

Uptake and intracellular activity of an optically active ofloxacin isomer in human neutrophils and tissue culture cells

The penetration of an optically active ofloxacin isomer [(-)-ofloxacin] into human neutrophils and different tissue culture cells (HEp-2, McCoy, MDCK, and Vero) was studied and compared with that of ofloxacin by a fluorometric assay. The cellular-to-extracellular-concentration ratios (C/E) of (-)-ofloxacin were always higher than 6, significantly greater than those of ofloxacin at extracellular concentrations of 5 and 10 mg/liter. The penetration of (-)-ofloxacin and ofloxacin was doubled when neutrophils were stimulated by phorbol myristate acetate but not affected after ingestion of opsonized Staphylococcus aureus. The C/E ratios of (-)-ofloxacin and ofloxacin for different tissue culture epithelial cells and fibroblasts were lower than those of neutrophils but still higher than 2. Both compounds produced a significant reduction in viable intraphagocytic S. aureus during 3 h of exposure to antimicrobial agents. We conclude that (-)-ofloxacin appears to reach higher intracellular concentrations than ofloxacin, remaining active inside the neutrophils

Intracellular penetration and activity of BAY Y 3118 in human polymorphonuclear leukocytes

The penetration of a new quinolone (BAY Y 3118) into human polymorphonuclear leukocytes (PMNs) was evaluated by a fluorometric assay. The cellular concentration-to-extracellular concentration (C/E) ratio was higher than 6.3 at extracellular concentrations ranging from 2 to 100 mg/liter. The uptake of BAY Y 3118 was rapid, reversible and nonsaturable. The intracellular penetration of BAY Y 3118 was significantly affected by environmental temperature (C/E ratio at 4°C, 5.4 ± 0.5; control, 7.5 ± 0.9; P < 0.05) and cell viability (C/E ratio in dead PMNs, 5.5 ± 0.8; control, 7.5 ± 0.9; P < 0.05), but it was not affected by metabolic inhibitors. The ingestion of opsonized zymosan or opsonized Staphylococcus aureus significantly decreased the levels of PMN-associated BAY Y 3118. Cell stimulation by a membrane activator, however, significantly increased the intracellular concentration of this quinolone. At therapeutic extracellular concentrations (0.5, 2, and 5 mg/liter), BAY Y 3118 showed intracellular activity greater than that of ciprofloxacin against S. aureus in human PMNs. It was concluded that BAY Y 3118 reaches high intracellular concentrations within human PMNs and remains active intracellularly

Uptake and intracellular activity of trovafloxacin in human phagocytes and tissue-cultured epithelial cells

The penetration of trovafloxacin into human polymorphonuclear leukocytes (PMNs), human peritoneal macrophages, and tissue-cultured epithelial cells (McCoy cells) was evaluated. The cellular concentration to extracellular concentration (C/E) ratios of trovafloxacin were greater than 9 for extracellular concentrations ranging from 0.5 to 25 μg/ml. The uptake of trovafloxacin by PMNs was rapid, reversible, nonsaturable, not energy dependent, and significantly increased at pH 6. The C/E ratios of trovafloxacin were not affected by cell viability but were significantly increased at 4°C. Ingestion of opsonized zymosan, but not opsonized Staphylococcus aureus, significantly increased the amount of PMN-associated trovafloxacin. This agent at concentrations of 0.5 and 1 μg/ml induced a greater reduction in the survival of intracellular S. aureus in PMNs than ciprofloxacin and ofloxacin. It was concluded that trovafloxacin reaches concentrations within phagocytic and nonphagocytic cells several times higher than the extracellular ones, while it remains active in PMNs

Infecciones orofaciales de origen odontogénico

La naturaleza polimicrobiana de las infecciones odontógenas así como la heterogeneidad de los cuadros clínicos asociados son consecuencia de la diversidad de la microbiota bucal y de la complejidad anatómica y funcional de la cavidad oral. Así mismo, estos procesos pueden dar lugar a múltiples complicaciones que pueden limitarse a afecciones locales o derivar hasta compromisos sistémicos. En el tratamiento farmacológico de estas infecciones es crucial la elección del antibiótico y la pauta posológica más eficaces. La farmacodinamia proporciona los parámetros que hacen posible valorar como varía la actividad de los antibióticos en función del tiempo. Como norma general, en el manejo inicial de las infecciones orofaciales en el adulto, incluidas las infecciones odontógenas, se utilizará amoxicilina/ac. Clavulánico en dosis de 875 mg de amoxicilina y 125 mg de ac. clavulánico pautado cada 8 horas. El cumplimiento terapéutico es clave para evitar la aparición de resistencias, por lo que se ha de maximizar la aceptación por parte de los pacientes. En este sentido se ha demostrado que la nueva presentación de 2000/125 mg de Augmentine Plus pautado cada 12 horas tanto en profilaxis como tratamiento disminuye significativamente la tasa de complicaciones infecciosas derivada de la extracción del tercer molar.The polymicrobial nature of the odontogenic infections as well as the variety of associated conditions are a consequence of the diversity of the buccal microbiota and the anatomical and functional complexity of the oral cavity. In addition to this, all these processes can give way to multiple complications which range from the local to the systemic level. The appropriate choice of antibiotic and posology is crucial in the successful management of these infections. Pharmacodynamics provides those parameters that make it possible to assess how antibiotics activity varies in time. As a general rule, the first step in the initial management of orofacial infections in adults, included odontogenic infections, will be the administration of 875 mg of amoxicillin and 125 mg of clavulanic every 8 hours. Therapeutic compliance is paramount to avoid resistance, therefore patient's acceptance must be sought. In this sense, it has been proved that Augmentine Plus (2000/125) every twelve hours both as profylaxis and as treatment significantly decreases the rate of infective complications associated to extraction of the third molar

Intracellular penetration and activity of gemifloxacin in human polymorphonuclear leukocytes

The intracellular penetration and activity of gemifloxacin in human polymorphonuclear leukocytes (PMN) were evaluated. Gemifloxacin reached intracellular concentrations eight times higher than extracellular concentrations. The uptake was rapid, reversible, and nonsaturable and was affected by environmental temperature, cell viability, and membrane stimuli. At therapeutic extracellular concentrations, gemifloxacin showed intracellular activity against Staphylococcus aureus

Uptake and intracellular activity of moxifloxacin in human neutrophils and tissue-cultured epithelial cells

The penetration by moxifloxacin of human neutrophils (polymorphonuclear leukocytes [PMN]) and tissue-cultured epithelial cells (McCoy cells) was evaluated by a fluorometric assay. At extracellular concentrations of 5 mg/liter, the cellular-to-extracellular concentration ratios (C/E) of moxifloxacin in PMN and McCoy cells were 10.9 ± 1.0 and 8.7 ± 1.0, respectively (20 min; 37°C). The uptake of moxifloxacin by PMN was rapid, reversible, nonsaturable (at extracellular concentrations ranging from 1 to 50 μg/ml), and not affected by cell viability. The uptake of moxifloxacin was affected by external pH and the environmental temperature. The incubation of PMN in the presence of sodium fluoride, sodium cyanide, and carbonyl cyanide m-chlorophenylhydrazone significantly decreased the C/E of this agent. Neither PMN stimulation nor phagocytosis of opsonized Staphylococcus aureus significantly affected the uptake of moxifloxacin by human PMN. This agent, at concentrations of 0.5, 1, and 5 mg/liter, induced a significant reduction in the survival of intracellular S. aureus in human PMN. In summary, moxifloxacin reaches much higher intracellular concentrations within phagocytic and nonphagocytic cells than extracellular ones, remaining active inside the neutrophils

In vitro activities of ketolide HMR 3647, macrolides, and clindamycin against coryneform bacteria

The in vitro activity of ketolide HMR 3647 against coryneform bacteria isolated from clinical samples was evaluated. Except against Corynebacterium jeikeium and C. urealyticum, HMR 3647 showed high activity against Corynebacterium spp., being more active than 14- and 16-membered macrolides, azithromycin, or clindamycin. HMR 3647 also had high in vitro activity against Brevibacterium spp. and Listeria monocytogenes

Uptake and intracellular activity of sparfloxacin in human polymorphonuclear leukocytes and tissue culture cells

The penetration of sparfloxacin into human neutrophils (PMN) and different tissue culture cells (HEp-2 and McCoy) was evaluated. The cellular to extracellular concentration ratios (C/E) of sparfloxacin were always higher than 4 at extracellular concentrations ranging from 0.5 to 25 mg/liter. The uptake of sparfloxacin by PMN was rapid, nonsaturable, reversible, not energy dependent, and significantly reduced at pH 8. The penetration of this agent into PMN was similar when viable and Formalin-killed cells were used and was not affected by environmental temperature. Ingestion of opsonized zymosan significantly increased the amount of PMN-associated sparfloxacin. Sparfloxacin at a concentration of 0.5 mg induced a significant reduction in the survival of intracellular Staphylococcus aureus. It is concluded that sparfloxacin reaches intracellular concentrations within leukocytic cells much higher than extracellular concentrations, while remaining active intracellularly