Species-typical behavior of hamsters deprived from birth of the neocortex.

Hamsters deprived from birth of the neocortex developed normally and displayed the usual hamster-typical behavioral patterns. With the additional concurrent destruction of midline limbic convolutions (cingulate and underlying dorsal hippocampal), there were deficits in maternal behavior and a lack of development of play behavior. These findings demonstrate in a rodent (i) that the striatal complex and limbic system, along with the remaining neuraxis, are sufficient for giving expression to a wide range of unlearned forms of species-typical behavior and (ii) that midline limbic structures are required for the expression of play behavior and the integrated performance of maternal behavior.

The integration of transabdominal ultrasound simulators into an ultrasound curriculum.

INTRODUCTION: Simulation is increasingly used throughout medicine. Within ultrasound, simulators are more established for learning transvaginal and interventional procedures. The use of modern high-fidelity transabdominal simulators is increasing, particularly in centres with large trainee numbers. There is no current literature on the value of these simulators in gaining competence in abdominal ultrasound. The aim was to investigate the impact of a new ultrasound curriculum, incorporating transabdominal simulators into the first year of training in a UK radiology academy. METHODS: The simulator group included 13 trainees. The preceding cohort of 15 trainees was the control group. After 10 months, a clinical assessment was performed to assess whether the new curriculum resulted in improved ultrasound skills. Questionnaires were designed to explore the acceptability of simulation training and whether it had any impact on confidence levels. RESULTS: Trainees who had received simulator-enriched training scored higher in an objective clinical ultrasound assessment, which was statistically significant (p = 0.0463). End confidence scores for obtaining diagnostic images and demonstrating pathology were also higher in the simulation group. All trainees stated that transabdominal simulator training was useful in early training. CONCLUSIONS: This initial study shows that embedded into a curriculum, transabdominal ultrasound simulators are an acceptable training method that can result in improved ultrasound skills and higher confidence levels. Using simulators early in training could allow trainees to master the basics, improve their confidence, enabling them to get more educational value from clinical ultrasound experience while reducing the impact of training on service provision.

DNA polymerases as engines for biotechnology.

This review examines the DNA polymerases, a class of enzymes that has been an essential tool for molecular biology research. Several families of DNA polymerases have been defined based on amino acid sequence comparisons, and new enzymes are continually being discovered, driving the expansion of the current classifications. Structural similarities among the enzymes are examined, as well as the functions of the various subunits and enzyme domains. The natural variety of polymerase activities has been harnessed for applications such as amplification, labeling, and detection of DNA sequences. In addition, enhancements to DNA polymerases by genetic engineering will be described, such as enzymes specifically designed for DNA sequencing by improving the incorporation of dideoxynucleotide terminators. Reverse transcription, the ability to use RNA as a template for DNA synthesis, is described for the application of making cDNA. We believe that new and unanticipated applications will emerge as new polymerases and mutated polymerases are created and characterized.

Glutathione, glutathione S-transferase, and transmembrane transport of glutathione conjugate in human neutrophil leukocytes.

Glutathione (GSH) conjugation is important in the detoxification of carcinogens and other exogenous electrophilic drugs and chemicals. The conjugation is catalyzed by GSH S-transferase. Neutrophil GSH content was 12.3 +/- 2.5 (mean +/- SD) nmol/10(7) cells, and transferase activity of cytosol preparations was 0.187 +/- 0.035 nmol/min/mg protein with 1-chloro-2,4-dinitrobenzene (CDNB) as substrate. Maximal activity was found at a pH of 7.0 and a temperature of 40 degrees C. Apparent Km of transferase was 1.25 +/- 0.18 mmol/L CDNB, and apparent Vmax was 0.621 +/- 0.22 nmol/min/mg. GSH-CDNB conjugate was quantitated by HPLC in cells and in medium after CDNB exposure. Transport of conjugate from cells to medium increased with CDNB concentration to 50 mumol/L, and kinetic data showed two saturable transport mechanisms with apparent Km of 5.90 mumol/L and 0.265 mumol/L, respectively. Cellular GSH content fell rapidly with CDNB concentration greater than 2.5 mumol/L, and was depleted in a 10-minute incubation at a concentration of greater than 50 mumol/L CDNB. Neutrophils have a significant content of GSH and a significant amount of transferase activity, and transport of GSH conjugate involves two distinct saturable pathways. GSH depletion can be accomplished with a relatively low concentration of an exogenous chemical and could impair the ability of the cells to carry out their phagocytic functions.