Non-epithelial neoplasms of the stomach.

Non-epithelial neoplasms of the stomach are rare in all countries, in contrast to neoplasms of epithelial origin. They can be either benign or malignant. The distinction between these two groups is based entirely on histopathology. This paper reports a series of 27 patients managed during the period June 1978 to March 1991.     

A measure of professors' attitudes towards the creativity of student nurses]

Creativity and problem solving are closely related in the learning and practice of nursing. The problem underlying this study concerns the attitudes of professors of nursing in 321 French language community colleges in Quebec toward the creative characteristics of their students. However, given the absence of a valid and reliable French instrument, this study focused on the validation of a French version of Torrance's Ideal Pupil Checklist. Content, construct and criteria validity were all verified, as well as the stability and homogeneity aspects of reliability.     

Distribution of alpha 2-adrenergic receptor mRNAs in the rat CNS.

alpha 2-Adrenergic receptors (ARs) are involved in central nervous system (CNS) control of blood pressure. It is now known that there are three human genes that encode subtypes of alpha 2-ARs, but little is known regarding the distribution of these subtypes throughout the CNS. The availability of receptor clones allows the mapping of mRNAs encoding the individual alpha 2-AR subtypes in the CNS. In this communication, we report that there are three, closely related rat alpha 2-AR genes. We have developed subtype-specific hybridization probes from each of these genes and have used these reagents to measure alpha 2-AR subtype mRNA accumulation in extracts of discrete regions of the rat CNS. We found that mRNAs encoding the alpha 2A-AR and alpha 2C-AR subtypes are distributed widely, but unevenly, throughout the rat CNS. The A subtype is prominent in the midbrain, brainstem, spinal cord, pituitary and diencephalon while the C subtype predominates in basal ganglia and cerebellum. The cortex, olfactory bulb and hippocampus contain roughly equal amounts of the alpha 2A- and alpha 2C-AR mRNAs. A third subtype's (alpha 2B-AR) mRNA is far less abundant in brain tissues, and is only found in the diencephalon.     

Neuropeptide levels in the basal ganglia of aged common marmosets following prolonged treatment with MPTP

Summary Aged common marmosets were treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 0.5–2.0 mg/kg/week i.p.) for 16 or 24 weeks, observed for a total of 30 weeks and then killed for measurement of biochemical pramaters in basal ganglia. The MPTP treatment induced a marked depletion in dopamine, 3,4-dihydroxyphenylacetic acid and homovanillic acid levels in the caudate nucleus and putamen. In contrast, the concentrations of five neuropeptides: [Met⁵]-enkephalin, [Leu⁵]-enkephalin, cholecystokinin, substance P and neurotensin as measured by a combined HPLC/RIA method, remained unaltered in all basal ganglia regions examined. Enkephalin precursor levels, as reflected by cryptic [Met⁵]-enkephalin content, were increased in the putamen, but not in the caudate nucleus, as a consequence of MPTP administration. Cryptic [Leu⁵]-enkephalin content remained unchanged in the striatum of MPTP treated marmosets. Overall, these results suggest an increase in striatal [Met⁵]-enkephalin release following chronic MPTP treatment of aged marmosets. However, the chronic treatment of aged marmosets with MPTP does not reproduce the neuropeptide alterations characteristic of Parkinson's disease.     

Sex effects in defensive behavior: Baseline differences and drug interactions

Female rats consistently show a pattern of differences in defensive behaviors compared to males which parallel the effects of exposure to a nonpainful threat stimulus (cat or cat odor) in the same tests and measures. These indications of greater defensiveness for females are particularly common in situations involving potential, as opposed to actual and present, threat, a factor which probably also reflects ceiling or floor effects in situations involving very intense defensiveness. In addition, pharmacological studies indicate sex differences in the effects of selective serotonin (5-HT) receptor agonists and antagonists on defensive responding. These findings indicate that sex effects must be considered in studies of the pharmacological control of defensive behaviors, and suggest that responsivity to sex effects may be an additional criterion for the suitability of animal models of anxiety.     

Thin slices of teleost retina continue to grow in culture

Thin slices of differentiated fish retinas were maintained up to 5 days in culture conditions where they exhibited properties essentially identical to those found in retinas of intact animals. Retinal slices were prepared by embedding eyecups from young fish in agarose and sectioning them on a vibratome. Phenotypic integrity of specific cell types was maintained, as demonstrated by specific antibody staining patterns. Stem cells in the retinal margin and presumptive rod progenitor cells in the outer nuclear layer continued to proliferate in vitro, just as they do in vivo. Some of these cells differentiated in vitro as demonstrated by labelling both cell division and cell phenotype. After several days in culture, some regeneration-like responses were observed, such as growth of neurites and swelling of cell bodies in the ganglion cell layer. This retinal slice preparation appears to offer a unique opportunity for studying the interactions among developing retinal cells.     

Testosterone and postnatal ontogenesis of hypothalamic mu ([3H]dihydromorphine) opioid receptors in the rat.

Brain opioids modulate the activity of the hypothalamo-pituitary complex by binding to specific receptors which have been subdivided at least into 3 subclasses (mu, kappa, delta, etc). mu-Receptors and their ligands seem to be particularly involved in the control of gonadotropin and prolactin release. It is known that the neuroendocrine system, as well as the brain opioid systems and their receptors, are not fully mature at birth; it is also known that the postnatal maturation of many brain machineries is under the control of androgens secreted by the developing testes. Consequently, it has been investigated whether the presence or the absence of testosterone at time of birth may induce changes of the binding characteristics of hypothalamic mu-opioid receptors. The experiments have been performed by evaluating the maximal binding capacity (Bmax, an index of the number of receptors), and the affinity constant (Ka) of the specific mu-ligand dihydromorphine in hypothalamic plasma membrane preparations derived from normal male rats, normal female rats, male rats orchidectomized 2 days after birth and female rats treated 2 days after birth with 1.25 mg of testosterone propionate. Animals belonging to the 4 groups were killed at days 16, 26 and 60 of age. The results obtained show that, at 16 days of age, in the 4 groups of rats the number of hypothalamic mu receptors is identical. At 26 days a significant increase in the number of mu-receptors occurs in normal female animals, while their levels remain similar to those found at 16 days in the other 3 groups of animals. At 60 days of age, the number of mu-receptors in normal females remains elevated, while the number of mu-receptors increases to reach normal female levels in the hypothalamus of neonatally castrated males. At 60 days, there were no changes in normal males or in androgenized females. The variations here reported took place without any change of the Ka of dihydromorphine for the mu-receptors. These data show a sexual dimorphism of hypothalamic mu-receptors and suggest that their ontogenetic development may be linked to the presence or the absence of androgens at time of birth.