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Biomedical subjects

J Weinberg

Publications and source records attributed to J Weinberg.

At least 181 records · Page 10Linked to original sources
PubMed1979

Long-term consequences of early iron deficiency in the rat.

A period of severe early iron deficiency (birth to 28 days of age) produced a persistent deficit (22%) in brain non-heme iron in adult rehabilitated animals. Long-term effects on behavior and physiological responsiveness were also observed. Although rehabilitated and control animals did not differ either in basal levels of plasma corticosterone or in the time course of the stress response following ether and cardiac puncture, possible differences in pituitary-adrenal responsiveness appeared to emerge following testing in an exploratory task. In addition, significant differences between rehabilitated and control animals were observed in both active and passive avoidance learning. Rehabilitated males made more intertrial responses than control males during active avoidance learning, and rehabilitated animals of both sexes performed better (i.e. showed longer reentry latencies) in a passive avoidance situation. It was suggested that shock may differentially affect motivation or arousal in rehabilitated and control animals.

Animals↗
PubMed1979

Urethane and contraction of vascular smooth muscle.

1 In vitro studies were undertaken on rat aortic strips and portal vein segments in order to determine whether or not the anaesthetic, urethane, can exert direct actions on vascular smooth muscle. 2 Urethane was found to inhibit development of spontaneous mechanical activity. This action took place with a urethane concentration as little as one tenth of that found in anaesthetic plasma concentratios, i.e., 10(-3) M. 3 Urethane (10(-3 to 10(-1) M) dose-dependently attenuated contractions induced by adrenaline, angiotensin and KCl. These inhibitory actions were observed with urethane added either before or after the induced contractions. 4 Ca2+-induced contractions of K+-depolarized aortae and portal veins were also attenuated, dose-dependently, by urethane. 5 All of these inhibitory effects were completely, and almost immediately, reversed upon washing out the anaesthetic from the organ baths. 6 A variety of pharmacological antagonists failed to mimic or affect the inhibitory effects induced by urethane. 7 These data suggest that plasma concentrations of urethane commonly associated with induction of surgical anaesthesia can induce, directly, relaxation of vascular muscle.

Angiotensin II↗
PubMed1979

Training sensory awareness and spatial organization in people with right brain damage.

Building on a methodology to improve scanning and academic skill performance behavior in persons with acquired right brain damage due to stroke, this study presents 2 additional treatment methods: training in sensory awareness and spatial organization. The 53 patients studied were divided into two groups, experimental (N = 30) and control (N = 23). The experimental group received a treatment program incorporating the 2 new methods as well as a condensed version of the original program. The controls received standard rehabilitation. Both groups were retested after 1 month. Analyses revealed that the performance of those in the experimental group exceeded that of the controls, that those patients in the experimental group with severe impairments improved more than those with mild impairments, and that combined multiple-treatment produces greater generalization than the original single treatment program.

Activities of Daily Living↗
PubMed1978

Differential effects of handling on exploration in male and female rats.

In this study, sex differences in the exploratory behavior of handled and nonhandled animals were measured under conditions of both high and low stimulus variation. The apparatus used was a hole-board, which provided an exploratory response independent of ambulation. Significant effects of handling were found: nonhandled animals decreased head-dipping over days whereas handled animals maintained a high rate. Sex differences were also observed: patterns of head-dipping for males and females differed over days depending on whether objects was present (high stimulus variation) or absent (low stimulus variation) under the hole-board; females also head-dipped for longer durations than males when objects were present; further, males and females showed completely opposite patterns of exploration depending on handling treatment and on level of stimulus variation. We conclude that handling differentially affects males and females, particularly as level of stimulus variability changes.

Animals↗
PubMed1978

Studies on kallikrein in the duct systems of the salivary glands of the cat.

By correlating immunofluorescence light microscopy with electron microscope studies and with kallikrein concentrations under various conditions, we have made the following observations and conclusions about kallikrein in the submandibular and other salivary glands.1. In the submandibular gland, specific immunofluorescence to kallikrein was observed in the luminal region of the striated ducts particularly, but also in the outer epithelial cells of the stratified epithelial collecting ducts. Sympathetic nerve stimulation resulted in a reduction in intensity of specific fluorescence and in its increased localization towards the lumen. The nearly complete elimination of kallikrein from the gland by duct obstruction for four days resulted in complete disappearance of specific fluorescence in the gland. Prolonged parasympathetic nerve stimulation at frequencies which did not reduce the kallikrein concentration of the gland failed to alter the specific immunofluorescence despite copious secretion of saliva. Our results failed to reveal evidence of secretion of kallikrein either into or towards the interstitium of the gland. The luminal layer of stratified epithelial cells in the collecting ducts contained small secretory granules closely resembling those in the striated ducts. Our results are not conclusive, but do suggest that kallikrein is located in these granules whence it is secreted into the lumen of the duct.2. The parotid gland was found to contain much lower concentrations of kallikrein than the submandibular gland. This finding was associated with the presence of far fewer striated ducts in the parotid gland. Otherwise, specific fluorescence and the response to sympathetic nerve stimulation was like that of the submandibular gland. Small secretory granules in the striated and collecting ducts resembled those of the submandibular gland.3. The sublingual gland, like the parotid, had a low concentration of kallikrein and very few striated ducts. These ducts were unevenly distributed and were concentrated in only a few lobules of the gland. Specific immunofluorescence was seen only in sections containing striated ducts.4. The possible physiological role of kallikrein in the salivary glands is discussed.

Animals↗
PubMed1977

Early handling influences on behavioral and physiological responses during active avoidance.

The effects of early handling on behavioral and physiological responses of the rat during active avoidance learning were investigated. Handled and nonhandled males and females were run in a 2-way shuttlebox task with an unconditioned stimulus of either .5 mA or .8 mA. Animals exposed to .8 mA showed a higher corticosterone response, a shorter response latency, and increased defecation. Early handling did not affect performance of the task, however handling did alter the patterns of the plasma corticosterone response over the course of avoidance training. Handled females showed less elevation of plasma corticosterone than nonhandled females, but all females showed a decrease in corticosterone over the course of avoidance learning. All males showed the drop in corticoids if run at .5 mA shock, but only handled males showed this change at .8 mA shock.

Animals↗