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Biomedical subjects

M L Nelson

Publications and source records attributed to M L Nelson.

47 records · Page 3Linked to original sources
PubMed1985

Protein supplementation of ammoniated roughages. III. Corncobs supplemented with a blood meal-corn gluten meal mixture--steer studies.

Two factorial experiments were conducted to investigate site and extent of organic matter (OM) digestion, nitrogenous fractions flowing at the abomasum and rates-of-passage in steers fed 0, 2 or 4 g NH3/100 g dry matter of treated corncobs supplemented with either a corn or a blood meal-corn gluten meal (BM-CGM) supplement. Rumen and total tract OM digestion coefficients were quadratically increased (P less than .05) and dietary N was quadratically increased (P less than .07) due to the main effect of ammonia. The main effect of protein supplement increased (P less than .05) postruminal OM digestibility, nonammonia N and dietary-N flow. Quadratic protein X ammonia interactions were noted for fluid flow, total-N flow, total amino acid flow and ammonia-N flow. Linear protein X ammonia interactions were noted for bacterial-N flow, which appeared to indicate that N utilization of the ammoniated corn-cob was improved by the inclusion of BM-CGM in the diet. Diet dry matter intake, fluid volume, rate of fluid passage, particulate mass and rate of particulate passage in rumen-fistulated steers were unaffected by either main effect. However, rumen fluid pH of steers fed BM-CGM was lower than that from steers fed the corn supplement.

Animal Feed↗
PubMed1984

Seasonal reproduction in the mongoose, Herpestes auropunctatus. IV. Organ weight and hormone changes in the female.

The mongoose, Herpestes auropunctatus, shows a well-defined breeding season in Hawaii. In this study, females were live-trapped throughout the year and sacrificed within 48 hr to obtain information about reproductive organ weights and gonadotropin levels. Pregnant females were found from February through September and lactating females from March through October. Body weight did not change significantly throughout the year, but anterior pituitary, adrenal, ovarian, and uterine weights were significantly reduced during the nonbreeding season. LH and FSH levels were extremely variable among individuals and, although mean values were higher during the breeding than during the non-breeding season, no significant differences could be demonstrated. After castration, there was not a clearcut rise in either LH or FSH, regardless of the season of the year, when animals were followed for up to l5 days. This contrasts with the male mongoose, where FSH rose significantly by 4 days after castration in either the breeding or nonbreeding season, while LH rose more slowly in the nonbreeding season but by l0 days after castration was significantly elevated and comparable to values in males castrated in the breeding season. We conclude that the female mongoose population shows less synchrony in changes in gonadotropin levels than the males, in spite of the well-defined breeding season.

Animals↗
PubMed1975

Effects of simulated high altitude (3800 m) on reproductive function in the pregnant rat.

Ovarian appearance, uterine contents (including numbers of fetuses, size and weight), and levels of gonadotropic hormones were studied in pregnant rats exposed to simulated altitude (3800 m). Comparisons were made at 11, 20 and 21 days of gestation between sea level controls rats bred at sea level and placed at reduced barometric pressure on confirmation of pregnancy (SHA). Although fewer fetuses were present in SHA rats on day 11 of gestation, litter size at days 20 and 21 was similar to controls. Body weight and length of SHA fetuses were significantly reduced by day 21 of gestation while placental weights remained similar to controls. The follicle-stimulating hormone (FSH) content in the pituitaries of SHA rats was significantly reduced at days 11 and 21 of pregnancy as compared with controls; luteinizing hormone (LH) content was lower at day 20 than at day 11 among SHA rats. Plasma gonadotropin levels were similar between SHA and control rats all all three stages of gestation. It is suggested that, despite lack of placental adaptation and altered endocrine functions, exposure of rats to hypoxic conditions only during gestation permits better maintenance of pregnancy than reported in rats with longer exposure to high altitude.

Adaptation, Physiological↗
PubMed1975

Pituitary hormones and growth retardation in rats raised at simulated high altitude (3800m).

Growth and the endocrine status of the pituitary and thyroid glands were studied in rats born and raised in a hypobaric chamber at a simulated high altitude of 3800 m (SHA); comparisons were drawn with similar rats at sea level. From birth until 40 days of age, SHA rats weighed significantly less than controls with the most striking growth impairment found in female SHA rats. Relative organ weights of anterior pituitary glands, ovaries and uteri from 40-day-old female SHA rats were significantly less than controls. Pituitary content of growth hormone (GH) was reduced in 40-day-old female SHA rats while the content of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were significantly increased over sea level controls. Plasma levels of GH, LH, FSH and thyrotropin (TSH) and pituitary TSH levels did not differ from control values. However, thyroidal uptake of 131I and plasma protein-bound 131I were significantly reduced in SHA rats as compared with controls. It is suggested that (1) the continuous exposure of developing female rats to hypoxia significantly impairs pituitary function and reproductive maturation, and (2) that despite other environmental factors acting on the developing organism at high altitude, growth retardation in rats born and raised at high altitudes is primarily a consequence of hypoxia.

Altitude↗
PubMedDate not supplied

A model for scholarship in nursing: the case of a private liberal arts college.

Faculty in the Department of Nursing at Augustana College, Sioux Falls, SD, focused their faculty development efforts for the 1997-1998 academic year on the creation of a scholarship model that would be both discipline-specific and relevant to Augustana's private liberal arts college identity. Rooted in Boyer's seminal re-examination of scholarship in academia, the Augustana model defines scholarship in nursing and delineates dimensions of scholarship, as well as the qualities of a scholar and criteria for evaluating scholarly endeavors. This evolving model has proven useful as a framework for faculty self-evaluation and peer review, as a guide for orienting undergraduate and graduate students to their own scholarly development, and as a framework to define criteria for final graduate student projects. The model is presented as an invitation to individual and collective scholarship development for every clinician, educator, theorist, and researcher in nursing.

Education, Nursing↗