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Biomedical subjects

P Stern

Publications and source records attributed to P Stern.

161 records · Page 9Linked to original sources
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Brain glycine and aggressive behavior.

Intraperitoneal glycine reduced aggressiveness caused by water deprivation or forebrain septal lesion in the rat. Nalorphine and mephenesin, drugs previously shown to elevate central glycine levels, acted in the same way as systemically administered glycine. In mice made aggressive by prolonged isolation, glycine and mephenesin acted as tranquilizers, but nalorphine failed to act. Aggressiveness in mice, induced by L-dopa or clonidine was enhanced by nalorphine and mephenesin, but was left unaffected by systemically administered glycine. Behavioral effects of glycine extend to other forms of excitation.

Aggression↗
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The effect of certain variables on the tumor and tissue distribution of tracers. II. Carrier effect: rapidity of onset and concentrations necessary for initiation and maximum response.

The smallest quantity of carrier Ga and Mn necessary to initiate and maximize a carrier effect was studied in the Morris 7777 rat hepatoma model. The quantity needed for a maximum response did not appear to adversely effect the rats. Not all tissues were equally affected at the same plasma concentrations. If carrier Ga was administered 2 hours following 67Ga injection and the rats sacrificed 30 minutes later, a dramatic change occurred in background activity, which was more pronounced in healthy than malignant tissues. Early viable and nonviable tumor/background ratios were improved by this technique. The data suggest that the use of carrier Ga and Mn might improve early lesion/background ratios in patients. This could be of use if tumor imaging were undertaken with 68Ga or 52mMn with positron detector systems.

Animals↗
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The effect of certain variables on the tumor and tissue distribution of tracers. III. Salicylates and vasoactive drugs.

Attempts were made to increase the viable tumor concentration of 54Mn and 67Ga in a rat hepatoma model by administering rat angiotensin, tolazoline, and salicylates. Salicylates increased the tumor concentrations of 54Mn and improved 65Mn viable tumor/background ratios. 67Ga was not affected by the salicylates. The salicylate effect appeared to be mediated by intracellular mechanisms rather than alterations in plasma protein binding. Rat angiotensin slightly increased the concentrations of 67Ga in the tumors but not enough to suggest that it would be useful clinically. Tolazoline did not increase tumor uptake of the tracers.

Animals↗
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The effect of certain variables on the tumor and tissue distribution of tracers. IV. False carriers: ferric citrate.

The intravenous administration of Fe+3 -citrate (1.6 mg/kg body weight) was demonstrated to alter the concentration of carrier-free 67Ga and 54Mn in malignant and healthy tissues of the rat, Morris 7777 hepatoma model. When the Fe+3 was injected 2 hours before, simultaneously with, or 2 hours after 67Ga (and the rats sacrificed 4 hours after injection), the 67Ga in most normal tissues decreased, and the viable tumor concentrations increased by 135, 24, and 47%, respectively. Twenty-four hours after a simultaneous administration of Fe+3 and 67Ga, egress of 67Ga from the tumor was much less than from the healthy tissues. These changes resulted in significant improvements in viable tumor to background ratios, especially at 4 hours. These changes induced in the distribution of the two tracers by Fe+3 indicate that some kinetic characteristics are shared. This is discussed in the light of their response to carrier Ga and Mn. The use of Fe+3 shows promise as a means of improving tumor/background ratios for 68Ga and 52mMn, two short-lived positron emitters that can be used with positron scanners. Gallium-67 imaging may also be improved by these techniques. The Fe+3 increases excretion of 67Ga from the animal, and this could result in a lower radiation dose to a patient.

Animals↗
PubMedDate not supplied

Student perceptions of a problem-based learning course.

Within occupational therapy education, there has been increased attention to curricula and courses that emphasize problem solving, clinical reasoning, and synthesis of information across traditional discipline-specific boundaries. This article describes the development, implementation, and outcomes of a problem-based learning course entitled Selected Cases in Occupational Therapy. The course was designed to help students to integrate the various elements of a specific occupational therapy curriculum and to enhance their abilities to respond to an ever-changing health care environment. An evaluation of the course by the first 11 students who completed it revealed both strengths and weaknesses. Students responded that the course enhanced their professional behavior, including interpersonal communication skills, team work, and follow-through with professional responsibilities; helped them to integrate the various elements of the total occupational therapy academic program; enhanced their clinical reasoning skills by providing a structure for thinking through clinical issues; and provided personal gain or benefit (i.e., students perceived the course to be a valuable, realistic, and motivating experience). The students also identified several specific course elements that contributed to its integrating function, including content, class session format, and students' role. Identified course weaknesses included the methods of evaluating student performance and the format and content of specific cases.

Curriculum↗
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Problem effectiveness in an occupational therapy problem-based learning course.

OBJECTIVE: The purpose of this study was to evaluate students' perceptions of the extent to which faculty-generated learning objectives were addressed in a problem-based learning (PBL) course. METHOD: Twenty-seven students enrolled in a 12-week PBL course were randomly divided by age, gender, and grade point average into four tutorial groups. Each group rated on a 10-cm visual analog scale their perceptions of how well they believed the objectives for each of four cases were addressed. Repeated-measures analysis of variance was used to test the average differences among the tutorial groups for each case. Further, post hoc tests were performed to compare the means among groups for each objective. RESULTS: No significant differences were found in the average perceptions among the tutorial groups for any of the four cases. Student ratings indicated their overall perception that within each problem, preset objectives had been met. CONCLUSION: The results support that students' interpretations of learning objectives for PBL cases are consistent with the problem developers' intended learning objectives. In addition, the similarities in the average scores for learning objectives across the four tutorial groups support the notion that PBL outcomes can be consistent among students, even though their study and discussions are in separate groups with different facilitators.

Humans↗
PubMedDate not supplied

Central effects of certain drugs and allergic encephalomyelitis in the circumstances of increased or decreased histamine in CNS.

The significance of the effect of histamine (Hi) in CNS has been demonstrated. By way of the inhibition of imidazol-N-methyltranspherase the amount of Hi in the brain can be increased, whereas by means of decaborane or thiazolil-metoxamine it can be lowered. It has been shown that Hi sensitizes the effect of acetylcholine (ACh) in CNS and, consequently, intensifies or weakens certain pharmacological reactions associated with ACh. It has been noted, as the most important result of the decreased Hi in CNS, that certain symptoms of motion sickness (such as vomiting, nistagmus etc.) disappear. Similarly, the increase of Hi in CNS prevents the development of the allergic encephalomyelitis in rats.

Animals↗