Chitosan is a large molecular weight, positively charged polysaccharide extracted and purified from the chitin of crab shells. This compound has been shown to have hemostatic activity and has been suggested for use as a topical agent in tissue repair. The objective of this study was to analyze the effect of chitosan on the wound healing response to a standardized injury in the rat. The polyvinyl alcohol sponge implant model was used as a means to deliver either chitosan or its vehicle to a standardized subcutaneous wound on the backs of Sprague-Dawley rats. On days 8 and 14, the chitosan-treated implants contained primarily polymorphonuclear leukocytes compared with the vehicle controls which contained mainly macrophages, fibroblasts, collagen, and new blood vessels. High-performance liquid chromatography analysis for hydroxy-L-proline deposited in the sponge implants showed significantly lower amounts on both days 8 and 14 in the chitosan treatment group. These histologic and biochemical studies suggest that chitosan modulates wound healing by first reducing the influx of activated tissue macrophages, which in turn reduces the subsequent events of angiogenesis, fibroplasia, and connective tissue deposition.

Journal Article↗

PubMedDate not supplied

Powerlessness regarding health-service barriers: construction of an instrument.

PURPOSE: The purpose of the study was to develop a scale to calculate college students' powerlessness regarding health service barriers (PHSB). METHODS: Scale items were generated to represent two domains of interest: powerlessness and college students' powerlessness regarding health service barriers. The final 20-item instrument was subjected to multiple measures of validity with college students and panels of nurse experts in the area of nursing diagnosis. Reliability was assessed by two samples (n = 92 and n = 33) of college-age students. A final administration was conducted with 197 college students. FINDINGS: The PHSB scale was determined to be an accurate and consistent measure. CONCLUSIONS: This instrument will provide a reliable and valid measure to conduct research.

Adolescent↗

PubMedDate not supplied

Daily variation in rat growth hormone concentration and the effect of stress on periodicity.

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Analysis of Variance↗

PubMedDate not supplied

Teaching nursing diagnoses to school nurses: a curriculum plan.

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Curriculum↗

PubMedDate not supplied

Teaching nursing diagnoses to school nurses: a standardized measure of the cognitive effect.

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Cognition↗

PubMedDate not supplied

Plasma corticosterone in stressed magnesium-deficient weanling rats.

A study was undertaken to learn whether the young Mg-deficient mammal can respond to major stress with increased levels of plasma corticosterone. Plasma corticosterone was determined in 48 weanling rats with dietary Mg deficiency and in 48 Mg-sufficient controls fed a Mg-supplemented diet, studying 12 animals at a time on experimental day 14. Each animal was studied once, either in an unstressed state or after the stress of audiogenic or strychnine seizures. Plasma corticosterone was determined using a radioimmunoassay; Mg was analyzed by atomic absorption spectrophotometry. On experimental day 14, unstressed Mg-deficient rats were tremulous, hyperirritable and showed slightly increased plasma corticosterone levels that exceeded controls levels. After strychnine shock, the mean plasma corticosterone levels of Mg-sufficient and Mg-deficient rats were both significantly increased over resting levels, and were not statistically different. Moreover, the spontaneous mortality rate that occurred during the experimental period in all Mg-sufficient rats was 0 compared to 27% among all Mg-deficient animals (p less than 0.0001). It was concluded that young rats deficient in Mg for 2 weeks could respond to major stress with levels of plasma corticosterone that were not significantly different from values of equally stressed Mg-sufficient controls. The deficient animals suffered a higher mortality, providing support for the concept that Mg deficiency increases stress-induced mortality in animals.

Animals↗

PubMedDate not supplied

Histidine, histamine, and the neuroregulation of food intake: a review and hypothesis.

Feeding, a behavior regulated by the central nervous system (CNS), includes the acquisition of specific essential nutrients and the maintenance of energy balance. Modulation of feeding behavior is a normal part of survival, but certain pathological conditions interrupt or modify regulatory aspects of feeding, thereby leading to inappropriate intake. This review examines aspects of metabolism associated with the anorexia seen in animals suffering from protein-energy malnutrition (PEM). The main focus is the indispensable amino acid histidine (His), the biosynthetic precursor of the neurotransmitter histamine (HA). In kwashiorkor-like PEM, His is elevated in plasma and brain, whereas all other indispensable amino acids are decreased. The elevation of His in the brain is to concentrations five times normal. Because the rate of HA synthesis in the brain is a function of the His concentration, His elevation raises the possibility of a profound direct effect of CNS function. In children, PEM consistently produces the symptoms of depressed food intake, edema, growth failure, and psychomotor changes. One known central effect of HA is the stimulation of ACTH and corticosteroid release. Based on these observations, the hypothesis being examined is as follows: one component of the pathophysiological neuroregulation of food intake involved the His-induced variation of HA concentration in the hypothalamus and the subsequently altered neurochemical activity at the corticotropin-releasing factor (CRF) neurons o the paraventricular nucleus (PVN).

Animals↗