Freezing temperature of finger skin

In 45 subjects, 154 frostnips of the finger were induced by cooling in air at -15 degrees C with various wind speeds. The mean supercooled skin temperature at which frostnip appeared was -9.4 degrees C. The mean skin temperature rise due to heat of fusion at ice crystallization was 5.3 degrees C. The skin temperature rose to what was termed the apparent freezing point. The relation of this point to the supercooled skin temperature was analyzed for the three wind speeds used. An apparent freezing point for a condition of no supercooling was calculated, estimating the highest temperature at which skin freezes at a given wind speed. The validity of the obtained differences in apparent freezing point was tested by an analysis of covariance. Although not statistically significant, the data suggest that the apparent freezing point with no supercooling decreases with increasing wind velocity. The highest calculated apparent freezing point at -15 degrees C and 6.8 m/s was 1.2 degrees C lower than the true freezing point for skin previously determined in brine, which is a statistically significant difference.     

An educational strategy for occupational therapy community service

In response to the increasing trend toward community health care, a model of training that prepares students for community practice was incorporated into the occupational therapy curriculum at the University of Southern California. During academic training students are placed in a part-time community assignment where no occupational therapy services are offered. Training students for the role of community health specialist produces a dilemma for curriculum design. A balance must be achieved between providing traditional clinical content and providing the knowledge and expertise necessary for community practice. However, this training is considered necessary for maintaining the viability of the profession in a changing health system. Significantly, during the four-year period using this model, many graduates have sought employment in "nontraditional" community roles.     

Expression of peptide YY in all four islet cell types in the developing mouse pancreas suggests a common peptide YY-producing progenitor

The islets of Langerhans contain four distinct endocrine cell types producing the hormones glucagon, insulin, somatostatin and pancreatic polypeptide. These cell lineages are thought to arise from a common, multipotential progenitor cell whose identity has not been well established. The pancreatic and intestinal hormone, peptide YY, has been previously identified in glucagon-producing cells in islets; however, transgenic mice expressing Simian Virus 40 large T antigen under the control of the peptide YY gene expressed the oncoprotein in beta, delta and pancreatic polypeptide cells, and occasionally developed insulinomas, suggesting relationships between peptide YY-producing cells and several islet cell lineages. The four established pancreatic islet cell types were examined for coexpression of peptide YY in islets of normal and transgenic mice throughout development. Peptide YY immunoreactivity was identified in the earliest endocrine cells in the fetal pancreas and was coexpressed in each islet cell type during development. Peptide YY showed a high degree of co-localization with glucagon- and insulin-producing cells in early pancreatic development, but by adulthood, peptide YY was expressed in less than half of the alpha cells and was no longer expressed in beta cells. Peptide YY was also coexpressed with somatostatin and pancreatic polypeptide when these cell types first appeared, but most delta and pancreatic polypeptide cells continued to express peptide YY throughout development. The use of conditions that distinguish peptide YY from the related peptides, pancreatic polypeptide and neuropeptide Y, as well as the ability of the peptide YY gene to direct expression of a reporter gene in islets of transgenic mice, establishes expression of peptide YY in the earliest pancreatic endocrine cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

Functional longevity of intraperioneal drains: an experimental evaluation

Various types of drains were inserted into the peritoneal cavity of twenty-eight dogs. After one to seven days, all drains failed to show the presence of 200 cc of colored fluid injected intraperitoneally. On autopsy, all tubes were surrounded and occluded by omentum.     

Upper extremity replantation: current concepts and patient selection

Dramatic advances in replantation and microsurgery have somewhat altered the criteria we use in selecting patients to be candidates for upper extremity replantation surgery. We suggest that contraindications for such replantation are: presence of associated life-threatening injuries; serious anesthetic risk; preexisting medical or psychiatric problems; previous injury or disease of the amputated part; warm ischemic time greater than 6-8 hours for extremities or greater than 10-12 hours for digits; and single-digit amputations (except thumb, for grasp). Replantation is feasible when: amputated part is properly preserved; injury type is sharp amputation, mild to moderate crush, or selected avulsion, and amputation is proximal to the DIP joint. Careful preservation of the amputated part, not in dry ice, is mandatory. On an individual basis, the decision to attempt replantation rests on the prediction that the patient may have better function with such surgery than with a prosthesis.