Oxytocin-immunoreactive innervation of identified neurons in the rat dorsal vagal complex.

BACKGROUND: Oxytocin (OXT) has been implicated in reproduction and social interactions and in the control of digestion and blood pressure. OXT-immunoreactive axons occur in the dorsal vagal complex (DVC; nucleus tractus solitarius, NTS, dorsal motor nucleus of the vagus, DMV, and area postrema, AP), which contains neurons that regulate autonomic homeostasis. The aim of the present work is to provide a systematic investigation of the OXT-immunoreactive innervation of dorsal motor nucleus of the vagus (DMV) neurons involved in the control of gastrointestinal (GI) function. METHODS: We studied DMV neurons identified by (i) prior injection of retrograde tracers in the stomach, ileum, or cervical vagus or (ii) induction of c-fos expression by glucoprivation with 2-deoxyglucose. Another subgroup of DMV neurons was identified electrophysiologically by stimulation of the cervical vagus and then juxtacellularly labeled with biotinamide. We used two- or three-color immunoperoxidase labeling for studies at the light microscopic level. KEY RESULTS: Close appositions from OXT-immunoreactive varicosities were found on the cell bodies, dendrites, and axons of DMV neurons that projected to the GI tract and that responded to 2-deoxyglucose and juxtacellularly labeled DMV neurons. Double staining for OXT and choline acetyltransferase revealed that OXT innervation was heavier in the caudal and lateral DMV than in other regions. OXT-immunoreactive varicosities also closely apposed a small subset of tyrosine hydroxylase-immunoreactive NTS and DMV neurons. CONCLUSIONS & INFERENCES: Our results provide the first anatomical evidence for direct OXT-immunoreactive innervation of GI-related neurons in the DMV.

Year-to-year correlations in blood metal levels among individuals of two species of North American sea ducks.

Sea duck populations have declined in North America. Contaminants, especially metals, have been listed as possible contributing factors. Sea ducks are long-lived. Thus, individuals chronically exposed to elevated metal levels may be at greatest risk. Information about long-term exposure (> or =1year) of individuals to metals is absent. To address this information gap, we examined year-to-year correlations among individual White-Winged Scoters and King Eiders in levels of blood cadmium, lead, mercury and selenium. Positive correlations (r> or =0.43), were found in six, five, five and two of seven correlations for cadmium, selenium, lead and mercury. Thus, certain individuals of these species may be exposed over two or more years to higher levels of cadmium, selenium and lead (but apparently not mercury) than other individuals. Single blood samples are appropriate metrics of exposure for studies that examine long-term effects of certain metals on these birds.

Effects of an exercise program on sick leave due to back pain.

The purposes of this study were to evaluate the effect of a weekly exercise program on short-term sick leave (less than 50 days) attributable to back pain and to determine whether changes in absenteeism were related to changes in cardiovascular fitness. Subjects were randomly assigned to an exercise group (n = 58) and a control group (n = 53). Sick leave attributable to back pain was determined in the intervention period of 1 1/2 years and a comparable 1 1/2-year period prior to the study. In the exercise group, the number of episodes of back pain and the number of sick-leave days attributable to back pain in the intervention period decreased by over 50%. Absenteeism attributable to back pain increased in the control group. The decrease in sick leave in the exercise group was not accompanied by any change in cardiovascular fitness. Suggestions for establishing exercise programs are given.

Evaluation of the hypolipaemic activity of etofylline clofibrate, a new ester of etofylline and clofibric acid, and comparison with effects of known hypolipaemic agents.

1-(Theophyllin-7-yl)-ethyl-2-[2-(p-chlorophenoxy)-2-methylpropionate] (etofylline clofibrate, ML 1024, Duolip) was compared with several reference compounds for effects on serum cholesterol and triglyceride levels of hypercholesterolaemic rats. ML 1024 appeared to be superior to the reference compounds in reducing cholesterol and triglyceride levels and may have a different mechanism of action to clofibrate.

A study of potential Olympic swimmers. Part 2. Changes due to three months intensive training.

Anthropometric and physiological measurements were recorded for a group of exceptional young swimmers undergoing an intensive training programme over 3 months. The observed changes are presented and are discussed in relation to the training undertaken, and are compared with expected changes due to normal growth. Some of the physiological parameters measured showed marked changes: average physical work capacity decreased significantly, while the physical fitness index improved. Many of the anthropometric changes were small, but a significant increase in lean body mass occurred in both boys and girls, and in both groups the average weight gain was greater than that expected. In individuals subjected to rigorous training significant changes in anthropometric and physiological parameters over and above the expected changes due to normal growth and development occur relatively quickly within a period of 3 months.

Effects of feeding lindane to dogs for periods of up to 2 years.

Lindane was administered to male and female Beagle dogs at dietary levels of 25, 50 and 100 ppm for 104 weeks, and of 200 ppm for 32 weeks. One death at 25 ppm and one at 200 ppm were not considered to be related to the test compound. At 100 and 200 ppm, SAP levels were raised and the livers were dark, friable and slightly enlarged but without any detected histopathological change. HVSA changes, possibly indicative of non-specific neuronal irritation, were recorded in the EEG tracings at 200 but not at 100 ppm. There were no other indications of an adverse effect of lindane. The negative findings at 50 ppm are consistent with a 'no-effect level' for this species of 1.25 mg/kg body weight, comparable with for the rat, and with proposed human ADI of 0.0125 mg/kg body weight.

A study of potential Olympic swimmers: I, the starting point.

Physiological and anthropometric profiles of a group of successful young swimmers are presented. Anthropometrically the swimmers appear to fall within fairly narrow limits but are physically more mature than their peers. Physiologically there is greater diversity within the group representing perhaps the varying demands of the swimming events practised. All values for the physiological parameters measured are high compared with children of similar ages. For the future it is hoped to relate performance in swimming to the variables measured and to assess any changes which occur thus perhaps colouring the profiles presented here.

The anti-inflammatory and analgesic effects of norvedan a novel, non-steroidal agent.

Norvedan (2-phenyl-4-p-chlorophenyl-thiazole-5-ylacetic acid) has been investigated for anti-inflammatory activity using an 'adjuvant arthirits' in rats and for analgesic activity using a writhing test in mice and a pressure test in rats. At oral doses of 10, 30 and 100 mg/kg Norvedan caused a dose-related inhibition of the primary swelling of the paw injected with adjuvant and the development of secondary lesions was also inhibited. Writhing induced in mice by i.p. administered acetic acid was also reduced by Norvedan at oral doses of 30 mg/kg and above and the response was related to dose. Against pain induced in rats by application of pressure to an inflamed paw Norvedan alsp showed good activity which was present for at least 6 hr after dosing.