Renaturation of formyltetrahydrofolate synthetase from urea and guanidinium chloride solutions

Formyltetrahydrofolate synthetase from Clostridium cylindrosporum and Clostridium acidi-urici was denatured in 6 M urea and 4 M guanidinium chloride. Viscometric, fluorimetric and ultracentrifugal measurements were used to determine that the protein is completely unfolded under these conditions. The polypeptide chains refold upon dilution of the denaturant-protein solutions to give final concentrations of 0.5 M urea or 0.1 M guanidinium chloride. In the presence of NH4+, but not in its absence, the refolded proteins associate to produce the catalytically active tetramer. Refolding and reassociation were followed by measuring changes in protein fluorescence and by determination of sedimentation constants. Under most conditions 80% of the enzymic activity is recovered.     

Hemodynamic responses to stellate ganglion stimulation in mongrels and greyhounds

A comparison of the effects of left stellate ganglion stimulation (SGS) on central and aortic hemodynamics has been made in chloralose-anesthetized mongrel (M), and greyhound (GH) dogs. Measurements of aortic pressure and flow, and left ventricular pressure were made during stimulation of the decentralized left SG at different frequencies from 0 to 20 Hz. The increases in aortic pressure and flow with SGS were larger in the GH, especially for low frequencies of stimulation. Stroke volume was increased with SGS in the GH at all stimulation rates, whereas in the M it was unchanged. A greater decrease in left ventricular end-diastolic pressure with SGS was found in the GH. These results suggest that differences exist in both the intrinsic and extrinsic control of cardiac output in the greyhound dog compared to the mongrel. These differences may be in part responsible for the elevated arterial blood pressure in the greyhound compared to the mongrel.     

Sodium oxacillin in the horse: serum, synovial fluid, peritoneal fluid, and urine concentrations after single-dose intramuscular administration

Six healthy adult mares were given a single dose (25 mg/kg of body weight) of sodium oxacillin IM. Oxacillin concentrations in serum, synovial fluid, peritoneal fluid, and urine were measured serially over a 48-hour period. The mean peak serum oxacillin concentration was 9.75 microgram/ml at 0.5 hour after injection. Mean peak oxacillin concentrations in synovial and peritoneal fluids were 1.45 microgram/ml and 2.60 microgram/ml at 1 hour and 2 hours, respectively. These concentrations decreased in parallel with serum values and were not measurable at 48 hours. Urine concentrations of oxacillin were high, with a mean peak concentration of 2,790.2 microgram/ml at 0.5 hour.     

Anticonvulsant drug concentrations in epileptic patients

Using Wistar stain male rats, it has been shown that 2 atmospheric pressures associated with oxygen saturation, together or singly for 90 minutes daily for successive 46 days, resulted in no significant change on the ratio of testes to body weight. No significant change was observed in the incorporation of 3H-thymidine into testes and pituitary glands between the pressure-treated groups and the control group.     

Combined transoral and median labiomandibular glossotomy approach to the upper cervical spine

A surgical approach to the clivus and anterior spine from C-1 to the upper part of C-5 is described. It is a direct approach that provides a wider and longer exposure than does the transoral approach. Despite the seemingly radical incision, the cosmetic deformity and functional loss are minimal. This approach is useful for the surgical treatment of a variety of processes that are situated ventral to the upper cervical spinal cord and the cervicomedullary junction.     

O-Buffer based IFT watershed from markers for large medical datasets

The watershed transform from markers is a very popular image segmentation operator. The image foresting transform (IFT) watershed is a common method to compute the watershed transform from markers using a priority queue, but which can consume too much memory when applied to three-dimensional medical datasets. This is a considerable limitation on the applicability of the IFT watershed, as the size of medical datasets keeps increasing at a faster pace than physical memory technologies develop. This paper presents the O-IFT watershed, a new type of IFT watershed based on the O-Buffer framework, and introduces an efficient data representation which considerably reduces the memory consumption of the algorithm. In addition, this paper introduces the O-Buckets, a new implementation of the priority queue which further reduces the memory consumption of the algorithm. The new O-IFT watershed with O-Buckets allows the application of the watershed transform from markers to large medical datasets.     

The optimal level of fuzz: case studies in a methodology for psychological research

Cognitive science research is hard to conduct, because researchers must take phenomena from the world and turn them into laboratory tasks for which a reasonable level of experimental control can be achieved. Consequently, research necessarily makes tradeoffs between internal validity (experimental control) and external validity (the degree to which a task represents behaviour outside of the lab). Researchers are thus seeking the best possible trade-off between these constraints, which we refer to as the optimal level of fuzz. We present two principles for finding the optimal level of fuzz, in research, and then illustrate these principles using research from motivation, individual differences and cognitive neuroscience.