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Biomedical subjects

S Rodriguez

Publications and source records attributed to S Rodriguez.

At least 73 records · Page 4Linked to original sources
PubMed1995

Concept mapping: an effective instructional strategy for diet therapy.

Concept mapping is an instructional strategy that requires learners to identify, graphically display, and link key concepts in instructional reading material. Although proven effective in numerous disciplines as a means to promote critical thinking and self-directed learning, concept mapping has not been tested in diet therapy. The objective of this study was to implement concept mapping as a small-group, cooperative learning strategy in an upper-division diet therapy course and to evaluate student attitudes about the effect of concept mapping on knowledge, self-directed learning, problem-solving, and collaborative skills. Students in the first semester (n = 27) initially learned course material by lecture (4 weeks) followed by an integrated mapping/lecture format (12 weeks); the second semester (n = 25) used an integrated mapping lecture format for the full 16 weeks. At the end of both semesters, students completed a 10-item original survey questionnaire. Responses for first (n = 25) and second (n = 21) semesters were analyzed independently. Results indicated that a majority of students thought participation in concept mapping enhanced knowledge of diet therapy principles (n = 19 of 25; 18 of 21), self-directed learning (n = 14 of 25; 18 of 21), critical thinking (n = 21 of 25; 14 of 21), problem-solving (n = 22 of 25; 16 of 21), and collaboration (n = 24 of 25; 20 of 21) skills. When noncooperation of teammates was a factor, concept mapping was viewed as more frustrating and time consuming than lecture. This study demonstrated concept mapping as an effective learning strategy for diet therapy; it improves students' ability to engage in self-directed learning, critical thinking, collaboration, and creative problem solving. Results suggest that concept mapping is most effective when accompanied with comprehensive training, coordinated lectures, instructor guidance, and long-term practice.

Concept Formation↗
PubMed1995

An antifungal naphthoquinone, xanthones and secoiridoids from Swertia calycina.

A chemical and biological screening of 25 species of the Gentianaceae family has been undertaken. Both methanolic and dichloromethane extracts of Swertia calycina exhibited a strong antifungal activity against Cladosporium cucumerinum and Candida albicans. The compound responsible for this activity has been isolated and identified as 2-methoxy-1,4-naphthoquinone. It is the first naphthoquinone to be described in Gentianaceae species. LC-UV and LC-TSP-MS analysis of the crude extracts of Swertia calycina also allowed on-line identification of six known xanthones and secoiridoids.

Antifungal Agents↗
PubMed1995

Silage or limit-fed grain growing diets for steers: I. Growth and carcass quality.

The influence of energy source (silage- [S] or grain- [G] based) on organ growth, carcass quality, and meat acceptability independent of rate of gain was examined. Sixty-four Angus steers were allotted to one of the two treatments and given ad libitum access to silage or limit-fed grain for 145 d. All steers were then given ad libitum access to a grain diet for 45, 75, or 105 d. Eight steers from each treatment were slaughtered at the end of the growing phase and at each of the termination dates. The silage-based growing diet consisted (DM basis) of 55% sorghum silage (averaged 23.6% dry matter), 22% alfalfa hay, 10.8% ground shelled corn, and 10.8% soybean meal and contained 12.8% CP. Dry matter in the grain-based diet, composed of 76.5% ground shelled corn, 5% soybean meal, 13.6% cottonseed hulls, 3.5% molasses, and .4% salt and 1% limestone, contained 12.1% CP. It was limit-fed to produce rates of gain similar to the silage diet eaten ad libitum, using net energy for gain of each diet calculated from organic matter digestibility determined in digestion trials. The finishing diet was similar to the grain growing diet except that alfalfa hay replaced the cottonseed hulls. No implants or ionophores were used. High silage moisture decreased ADG the first 45 d, so steers fed grain gained faster, but thereafter gains were similar. At the end of the growing phase, steers fed grain had heavier shrunk and empty body weights and larger livers. However, liver size was not different when adjusted for growing ADG. By 45 d with ad libitum access to the finishing diet, 75% of the carcasses from steers fed both diets graded Choice. Steers fed silage had tougher (P < .05) steaks with less flavor intensity (P < .05) at the end of the growing phase; these differences diminished after 75 d on feed. These results suggest that choice beef can be produced in only 45 d in the feedlot, but tenderness and flavor among Choice carcasses remained inferior for steers fed silage for at least 75 d on a high-grain diet.

Animals↗
PubMed1995

Silage or limit-fed grain growing diets for steers: II. Empty body and carcass composition.

The influence of energy source (silage- or grain-based) on empty body and carcass composition and adipocyte cellularity independent of rate of gain was tested. Sixty-four Angus steers were allotted to either a forage (ad libitum) or grain (limit-fed) diet for a growing phase (145 d) followed by 45, 75, or 105 d of ad libitum access to a grain-based diet. Eight steers were slaughtered initially and eight from each treatment were slaughtered at the end of the growing phase, and at each of the termination dates. The silage growing diet consisted (DM basis) of 55% sorghum silage (approximately 24% dry matter), 22% alfalfa hay, 11% ground shelled corn, and 11% soybean meal. The grain-based growing diet was composed of 77% ground shelled corn, 5% soybean meal, 14% cottonseed hulls, 3% molasses, and 1% salt and mineral; it was limit-fed to produce the same rate of gain as the silage diet. No implants or ionophores were used. At the end of the growing phase, the steers fed grain were heavier and had a higher percentage of fat in the empty body (24 vs 19% fat) and the carcass (26 vs 21% fat) than did steers fed forage. Rate of gain during the growth phase was related positively to percentage of carcass fat; when corrected for fill, data for both diets fit one regression line for fat vs rate of gain. When adjusted for gain during the growing phase, fat content was not different in empty body or carcass, but internal fat was higher (P < .10) for steers fed grain. After 45 d on the finishing diet, carcass fat remained low (23%), but after 75 and 105 d, fat content reached 27%. Source of energy did not detectably affect carcass composition independent of rate of gain. Cell size of adipocytes from four adipose depots increased with time on feed but were not affected by diet during the growing phase. Lean Choice beef can be produced in only 45 d in the feedlot with medium-framed Angus cattle.

Adipose Tissue↗
PubMed1994

Hepatoprotective effects of diethylcarbamazine in acute liver damage induced by carbon tetrachloride in rats.

This research was carried out to determine a potential role of leukotrienes in the acute hepatotoxicity induced by CCl4 in rats. An inhibitor of leukotrienes biosynthesis, diethylcarbamazine (DEC, 25 and 50 mg.kg-1 ip) exerted hepatoprotective effects, decreasing the activity of alanine aminotransferase in serum and the concentration of liver triglycerides. DEC reduced histological damage of liver evidenced by electron microscopy. The hepatoprotective effects of DEC were dose-dependent. The results favor the role of leukotrienes in CCl4 hepatotoxicity.

Alanine Transaminase↗