Ultrasound-triggered drug targeting of tumors in vitro and in vivo.

The new modality of drug targeting of tumors that we are currently developing is based on drug encapsulation in polymeric micelles, followed by the localized release at the tumor site triggered by focused ultrasound. The rationale behind this approach is that drug encapsulation in micelles decreases systemic concentration of drug, diminishes intracellular drug uptake by normal cells, and provides passive drug targeting of tumors, thus reducing unwanted drug interactions with healthy tissues. Ultrasound irradiation is used to release drug from micelles at the tumor site and to enhance the intracellular drug uptake by tumor cells. An important advantage of ultrasound is that it is noninvasive, can penetrate deep into the interior of the body, can be focused and carefully controlled. Here we describe factors involved in the ultrasound interaction with viable cells in the absence and presence of drug carriers and anti-cancer drugs. We present in vivo effects of 1 MHz ultrasound on drug biodistribution, intratumoral distribution, and survival rates of immuno-compromised athymic nu/nu mice bearing ovarian carcinoma tumors.

Soporte nutricional post-operatorio de cirugía abdominal en paciente pediátrico / Nutritional support post-operative of abdominal surgery in pediatric patient

Paciente varón de 11 años, ingresa a UTI con diagnóstico de traumatismo cerrado abdomino-pelviano. El día posterior al ingreso se realiza la parotomía exploradora donde se constata sección completa de yeyuno a 20 cm del angulo Treitz y perforación a 10 cm del aza fija; resecándose 30 cm de yeyuno con anastomosis término-terminal. Se realiza nutrición parenteral total (NPT) desde las 72 horas posteriores al ingreso. Debido a la mala evolución del paciente debe reintervenirse en varias oportunidades, realizandose finalmente ostomía a cabos divorciados (a los 10 días del ingreso). Además desarrolla sépsis que debe tratarse con antibióticoterápia de amplio espectro. Tan pronto como fue posible (3 días de la yeyunostomía) y acompañando a la NPT, se indicó nutrición enteral a débito continuo con formula semielemental y reinfusión del débito de ostomía proximal por el cabo distal. A los 40 días pudo suspenderse la nutrición parenteral ...

Unusual single-stranded polyribonucleotides as potent anti-HIV agents.

Polyribonucleotides (PTMG and PMTI) containing 1-methyl-6-thioguanosine or 1-methyl-6-thioinosine, respectively, as the sole nucleoside component are shown to be potent inhibitors of various strains of HIV-1 and HIV-2 in a number of human lymphocyte and macrophage cell lines in tissue culture as well as in fresh human peripheral blood lymphocytes and macrophages. PMTI and PMTG exhibit potencies in the range of 10(-7)-10(-8) M in these systems. The polynucleotides are active against virus strains resistant to AZT and pyridinone derivatives. Both PMTI and PMTG are synergistic with AZT and with ddI, and both inhibit HIV reverse transcriptase at nanomolar concentrations. The polymers show little or no toxicity in human cell lines at the highest doses tested (100 micrograms/mL, or about 0.2-1 microM). This class of compounds represents a new lead in AIDS therapeutic drug discovery.

Síndrome de diarrea grave prolongada y nutrición parenteral / Syndrome of prolonged gravis diarrhea and parenteral nutrition

La diarrea grave prolongada de la infancia debe considerarse una enfermedad nutriciónal. La formas de tratamiento descriptas son la nutricional enteral a débito continuo (NEDC) y la nutrición parenteral total (NPT). Ante el fracaso de una NEDC utilizando fórmulas semielementales se impone la NPT. Se revisan en este estudio, en forma retrospectiva, trece casos de diarrea grave prolongada que requirieron NPT. Doce de ellos, luego de un tiempo en promedio de veinte dias de NPT, pudieron continuar su recuperación nutricional con NEDC. Uno falleció por complicación quirúrgica de su enfermedad. La NTP se muestra como alternativa eficaz ante el fracaso de la NEDC, en el soporte nutricional de la diarrea grave prolongada.

Comparison of three anaesthetic scavenging devices using cuffed and noncuffed nasal endotracheal tubes during dental anaesthesia.

During maxillofacial and oral surgery the effect of three anaesthetic scavenging devices used with cuffed and non-cuffed endotracheal tubes was investigated. All the devices produced reductions in nitrous oxide concentrations in the breathing zone and peripheral air, ranging from 36% to 76%. Of the three devices evaluated, the Stellenbosch valve produced the greatest reduction in pollution compared with the control.

Early and late scavenging of anaesthetic gases.

The effectiveness of two waste gas scavenger devices, the Carstens box and the Ventex apparatus, with regard to nitrous oxide pollution was studied under comparable conditions in an operating theatre. The scavengers were brought into use in the early and late stages of induction of anesthesia, and nitrous oxide concentrations in the breathing zone and theatre peripheral air were measured. Both scavengers reduced nitrous oxide pollution at the sampling points. Similar reductions in nitrous oxide pollution in the breathing zone were obtained with both scavengers, but the Carstens box was more effective in reducing nitrous oxide pollution in the peripheral air.