Analyzing the biosensor signal in flows: studies with glucose optrodes.

Responses of enzymatic bio-optrodes in flow regime were studied and an original model was proposed with the aim of establishing a reliable method for a quick determination of biosensor signal parameters, applicable for biosensor calibration. A dual-optrode glucose biosensor, comprising of a glucose bio-optrode and a reference oxygen optrode, both placed into identical flow channels, was developed and used as a model system. The signal parameters of this biosensor at different substrate concentrations were not dependent on the speed of the probe flow and could be determined from the initial part of the biosensor transient phase signal, providing a valuable tool for rapid analysis. In addition, the model helped to design the biosensor system with reduced impact of enzyme inactivation to the system stability (20% decrease of the enzyme activity lead to only a 1% decrease of the slope of the calibration curve) and hence significantly prolong the effective lifetime of bio-optrodes.

Stimulation of 5-HT1B receptors decreases cocaine- and sucrose-seeking behavior.

Serotonin systems have been implicated in incentive motivation for cocaine, yet little is known about the role of 5-HT(1B) receptors in these processes. We used the extinction/reinstatement model to examine the effects of the 5-HT(1B/1A) receptor agonist, RU24969, on reinstatement of extinguished cocaine-seeking behavior. Rats trained to self-administer cocaine subsequently underwent extinction. They were then tested twice for cue and cocaine-primed reinstatement of extinguished cocaine-seeking behavior, receiving saline pretreatment 1 day and their assigned dose of RU24969 (0.3, 1.0, 3.0 mg/kg) the other day. Rats were later trained on a schedule of sucrose reinforcement in novel chambers and then tested for effects of RU24969 on cue reinstatement of sucrose-seeking behavior and locomotion. RU24969 decreased cue and cocaine reinstatement of cocaine-seeking behavior and cue reinstatement of sucrose-seeking behavior. Locomotion was increased only at the highest RU24969 dose (3 mg/kg). A subsequent experiment demonstrated that the effects of RU24969 (1 mg/kg) on extinguished cocaine-seeking behavior were reversed by the 5-HT(1B) antagonist GR127935 (3 mg/kg). These findings suggest that the effects of RU24969 on cue and cocaine reinstatement of cocaine-seeking behavior are 5-HT(1B) receptor-mediated. Overall, the results suggest that stimulation of 5-HT(1B) receptors may produce a general decrease in motivation.

Cargo delivery kinetics of cell-penetrating peptides.

A diversity of cell-penetrating peptides (CPPs), is known, but so far the only common denominator for these peptides is the ability to gain cell entry in an energy-independent manner. The mechanism used by CPPs for cell entry is largely unknown, and data comparing the different peptides are lacking. In order to gain more information about the cell-penetrating process, as well as to quantitatively compare the uptake efficiency of different CPPs, we have studied the cellular uptake and cargo delivery kinetics of penetratin, transportan, Tat (48-60) and MAP (KLAL). The respective CPPs (labelled with the fluorescence quencher, 3-nitrotyrosine) are coupled to small a pentapeptide cargo (labelled with the 2-amino benzoic acid fluorophore) via a disulfide bond. The cellular uptake of the cargo is registered as an increase in fluorescence intensity when the disulfide bond of the CPP-S-S-cargo construct is reduced in the intracellular milieu. Our data show that MAP has the fastest uptake, followed by transportan, Tat(48-60) and, last, penetratin. Similarly, MAP has the highest cargo delivery efficiency, followed by transportan, Tat (48-60) and, last, penetratin. Since some CPPs have been found to be toxic at high concentration, we characterized the influence of CPPs on cellular 2-[(3)H]deoxyglucose-6-phosphate leakage. Measurements on this system show that the membrane-disturbing potential appears to be correlated with the hydrophobic moment of the peptides. In summary, the yield and kinetics of cellular cargo delivery for four different CPPs has been quantitatively characterized.

Do ant mosaics exist in pristine lowland rain forests?

Ant mosaics have been described as characteristic elements of arboreal ant communities from tropical plantations, and it is often assumed that they also exist in undisturbed lowland rain forests. Until now, however, there have been no studies from pristine rain forests to show this. Our investigations on the mechanisms structuring arboreal arthropod communities in a southeast-Asian lowland rain forest allowed us to compare our results with the predictions of the ant mosaic theory. According to this theory aggressive dominant ant species should maintain mutually exclusive territories. Furthermore, communities of associated nesting species dominated by the same dominant species should be more similar to each other than communities governed by other dominants. The ant communities of 19 individuals of three understorey tree species were collected with an improved method of canopy fogging that guaranteed selective tree sampling in a multilayered rain forest. Ten trees were re-fogged after 6 months and seven again after 3 years to investigate whether the reorganization of the ant communities occurred in a similar way. To test whether the pattern of an ant mosaic emerged when not only single trees but also somewhat larger areas containing several adjacent trees were sampled, we collected the nesting ant species from a group of Aporusa lagenocarpa with tuna baits. All ant communities were highly heterogeneous in their species composition and neither negative nor positive species associations were found. The lack of an ant mosaic in mature forests is also suggested by a Monte Carlo computer simulation, according to which ant community composition differed only slightly from random. The re-fogged communities showed the same structural heterogeneity as was found in the first fogged communities, without any observable convergence to the original species composition. No pioneer or climax species could be identified. All results combined indicate that the ant mosaic theory does not apply to the mature lowland rain forest investigated, where community organization seems to be the product of very complex dynamic processes.

Minimal forces to move patients.

OBJECTIVES: Health care workers who have patient transfer duties are at risk for back injury. Transferring patients between beds and gurneys is a rigorous pulling task that requires back, leg, and arm strength. This study analyzed the efficiency of commercially available transfer devices, namely a patient roller, patient shifter, and draw sheet. METHOD: With the use of one or two force scales attached to each transfer device, the amount of force needed to transfer 15 participants, weighing from 101 lb to 240 lb, back and forth between a bed and a gurney was measured. Ten transfers per device per participant were performed. RESULTS: The patient roller was superior to the patient shifter and draw sheet in reducing transfer forces. Additionally, gurney-to-bed transfers tended to be more demanding for all transfer devices and for heavier participants. CONCLUSIONS: The patient roller was the most efficient transfer device in moving participants compared with the draw sheet and patient shifter. Transfer forces can be estimated with the use of linear equations, with patient weight, direction of transfer, and transfer device as the independent variables. These estimated forces can assist occupational therapists in the returning their injured health care coworkers to patient transfer duties. The results further indicated that high forces are required to transfer patients; therefore, patient-transfer personnel should obtain assistance when moving patients.

Urine drug screening and the family physician.

Urine screening for drugs is increasingly employed in the United States in an effort to reduce illegal drug use and its consequent morbidity, mortality and economic burden. The family physician may choose to ensure proper urine specimen collection or may choose to develop expertise as a medical review officer; training courses and materials are available. In addition, certification is available from several organizations. The physician who becomes a medical review officer is responsible for interpreting positive tests and may also become involved in drug rehabilitation programs. It is prudent to follow federal guidelines for occupational urine drug screening, even when these guidelines are not mandatory, to protect against a possible challenge to a positive specimen on the grounds of improper processing. In all cases, care should be taken to correctly identify the patient, to label all specimens and to document that the specimen has been secured against tampering.

Evaluacion audiologica en ninos que han recibido terapia intensiva en el periodo neonatal. / Audiologic evaluation of infants that received intensive care treatment in neonatal period

Se presentan los resultados audiometricos de 21 ninos que recibieron terapia intensiva en el periodo neonatal. Estan divididos en 3 grupos segun su diagnostico final: sepsis, hiperbilirrubinemia y meningitis, siendo los resultados 27%, 28.5% y 100% de perdida auditiva respectivamente para un total de 38% de perdida si se suman todos los grupos. Se evalua el nivel de ruido producido en la sala de terapia intensiva, encontrandose niveles de hasta 96 decibeles. Se recomienda el tratamiento precoz de las enfermedades del neonato y controlar en lo posible el nivel de ruido de las salas de terapia intensiva

Sindrome hemolitico uremico: comunicacion de dos casos. / Hemolytic-uremic syndrome: communication of two cases

Se comunican dos casos de sindrome hemolitico uremico (SHU) en dos ninos de 10 meses y 2 anos de edad. Ambos pacientes presentaron insuficiencia renal aguda (IRA), cuya severidad amerito manejo con dialisis peritoneal respondiendo satisfactoriamente. Por otra parte los autores discuten los aspectos relacionados con la fisiopatologia de la trombocitopenia y de la anemia hemolitica microangiopatica. Finalmente se analiza la terapeutica del sindrome

Cetoacidosis diabetica. Experiencia en una unidad de cuidados intensivos. / Diabetic ketoacidosis. Experience in a intensive care unit

Los autores presentan su experiencia en el manejo de 16 ninos con ceto-acidosis diabetica en una unidad de cuidados intensivos, puntualizando que los resultados optimos estan en relacion con la atencion integral, adecuada y permanente durante la etapa critica de las primeras horas. La mortalidad en este grupo fue de 12,5% y relacionada con factores no precisamente dependientes del desorden metabolico propriamente dicho (meningitis purulenta, insuficiencia renal)