Effects of modulatory agents on neurally-mediated responses of trout intestinal smooth musclein vitro.

Mediators and mechanisms responsible for the inhibitory modulation of trout intestinal smooth muscle were examined using a series of putative mediators and substances known to modulate neurotransmission in mammalian systems. Frequency response relationships to transmural stimulation and concentration response relationships to 5-hydroxytryptamine, carbachol, and substance P were established on paired segments of rainbow trout intestinein vitro in the presence and absence of putative modulatory agents. Modulation of neurally-mediated contractions of trout intestine was achieved with dibutyryl cyclic AMP and forskolin, agents that increase intracellular levels of cyclic AMP. The effect appears to be at the level of the smooth muscle, since the adenylate cyclase activator, forskolin, inhibited muscarinic and serotoninergic contractions as well as transmurally stimulated contractions. Substance P-induced contractions were unaffected by forskolin. The endogenous agonists/neurotransmitters which would increase cyclic AMP levels in rainbow trout intestinal smooth muscle are as yet unknown. The effects do not appear to be modulated by vasoactive intestinal peptide (VIP), calcitonin, calcitonin gene-related peptide (CGRP), or agents that activate ß-adrenoceptors. Prostaglandin E2 (PGE2) and α2-adrenergenic agonists are possible agents which will decrease contractility of the smooth muscle. They were only active in the proximal intestine and on transmurally stimulated contractions. The effects of both PGE2 and α2-agonists appear to be prejunctional, decreasing release of contractile neurotransmitters in the enteric nervous system.

Changes in smooth muscle contractility of rainbow trout (Oncorhynchus mykiss Walbaum) intestine during acclimation to altered temperature.

The effects of altered water temperature in vivo on in vitro smooth muscle contractility of rainbow trout intestine were investigated. Temperature has a significant effect on receptor-mediated intestinal smooth muscle contractility in the rainbow trout. The efficacy of 5-HT, carbachol, and transmural stimulation increased with temperatures above 10°C, with an optimal increase at 15°C. There was also a modest increase in the potency of 5-HT and carbachol within 2 days of establishing trout at 20°C. By day 8, most of these changes had either stabilized or were returning to control values, suggesting that acclimation changes in membranes and enzyme activities were taking effect. However, the contractile responses to carbachol and transmural stimulation were still increasing at this time. This may imply that the muscarinic receptors are more resistant to membrane acclimation changes and may take longer to adapt. Because these experiments were controlled for handling stress and seasonal changes that affect contractility, we have been able to demonstrate some early changes in smooth muscle contractility that occur during acclimation to altered temperature.

Evaluation and implementation of public health registries.

A rapid proliferation of registries has occurred during the last 20 years. Given the long-term commitment of resources associated with registries and limited public health funding, proposals for new registries should be carefully considered before being funded. A registry is defined as a data base of identifiable persons containing a clearly defined set of health and demographic data collected for a specific public health purpose. Criteria for evaluating whether a registry is needed, feasible, or the most effective and efficient means of collecting a specific set of health data are presented. They include an evaluation of the stated purpose; a review of the function, duration, and scope of the registry; consideration of existing alternative data sources; an assessment of the practical feasibility of the registry; the likelihood of sufficient start-up and long-term funding; and an evaluation of the cost effectiveness of the registry. Creating a public health registry is a complex process. A range of technical and organizational skills is required for a registry to be successfully implemented. Eight requirements are identified as crucial for the successful development of a new registry. They include an implementation plan, adequate documentation, quality control procedures, case definition and case-finding (ascertainment) procedures, determination of data elements, data collection and processing procedures, data access policy, and a framework for dissemination of registry data and findings.

Analysis of a father's speech to his language-learning child.

This study analyzed the speech of a father to his language-learning child. Father-to-child speech was taped daily over a two-week period when the child was three years old. Results indicated that declarative (35%) and interrogative (34%) sentences occurred most often. Smaller percentages of exclamatory (9%) and imperative (6%) sentences were found. The father rarely repeated his own utterances and almost never expanded his daughter's utterances. The child rarely immediately imitated her father's utterances. Comparisons are made of aspects of father-to-child speech with mother-to-child speech as reported in previous investigations.