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Biomedical subjects

C L DePew

Publications and source records attributed to C L DePew.

14 recordsLinked to original sources
PubMed1997

Prolactin, gonadotropin, and hair shedding responses to daily sulpiride administration in geldings in winter.

This experiment was designed to determine 1) the efficacy of daily s.c. injections of a dopamine antagonist, sulpiride, for increasing prolactin secretion in geldings in winter and 2) whether increasing prolactin concentrations would hasten the onset of hair shedding or enhance gonadotropin secretion. Five geldings each received vehicle (vegetable oil) or sulpiride (100 mg in vehicle) daily from February 8 through March 29. On February 8 and every 7 d thereafter through March 29, blood samples were drawn around treatment injections and hair samples were collected. On March 30, all geldings received an injection of GnRH and thyrotropin-releasing hormone. Over the 8-wk sampling period, prolactin response to sulpiride varied in a quadratic manner (P < .002). Average area under the 2-h response curve for sulpiride-treated geldings was 24.9 h.ng.mL-1 on February 8, declined to 4.3 after 4 wk, and then increased to 14.8 by the 8th wk of treatment (pooled SE = 4.1 h.ng.mL-1). Prolactin concentrations in control geldings did not vary (P > .1) after injection or over the 8-wk period. Weight of hair pulled from sulpiride-treated geldings did not peak as sharply or as high as that from control gelding (P < .05) and continued to be high through the 11th wk. Sulpiride treatment reduced (P = .071) the LH response to GnRH on March 30; the FSH and prolactin responses to secretagogue were not altered (P > .25). In conclusion, even though prolactin concentrations were increased by sulpiride, the effects on gonadotropin secretion and hair shedding were minor and opposite of those expected.

Animals↗
PubMed1997

Prolactin administration to seasonally anestrous mares: reproductive, metabolic, and hair-shedding responses.

Eight pony mares received 4 mg of recombinant porcine prolactin (rpPRL) daily for 45 d beginning on January 15; eight control mares received vehicle. Reproductive end points and various indicators of metabolism, hair shedding, and thyroid activity were monitored. Prolactin concentrations peaked in mares treated with rpPRL at 94 +/- 19 ng/mL 2 h after injection and were 5.1 +/- 1.7 ng/mL 24 h after injection. Treatment with rpPRL increased (P < .01) hair shedding within 14 d, which peaked at 28 d and then dropped precipitously. Binding of 125I-equine prolactin confirmed that antibodies were present in rpPRL-treated mares by 28 d, thus only data up to that time are included herein. The percentage of mares in estrus after 17 d of treatment was greater (P < .05) for mares treated with rpPRL than for controls, although the average day of estrus onset did not differ (P > .1). The date of first ovulation, determined from plasma progesterone concentrations, was hastened (P < .005) in mares treated with rpPRL (February 6 +/- 3 d) relative to control mares (March 14 +/- 6 d). Concentrations of insulin-like growth factor I and nonesterified fatty acids were not affected (P < .05) over time. There were minor differences between groups in thyroid hormone secretion. Various assessments of glucose and insulin indicated no perturbation (P > .1) due to treatment with rpPRL. We conclude that prolactin mediates the onset of vernal hair shedding in mares and is in some way involved with ovulation.

Anestrus↗
PubMed1995

Dietary protein and(or) energy restriction in mares: plasma glucose, insulin, nonesterified fatty acid, and urea nitrogen responses to feeding, glucose, and epinephrine.

Sixteen light horse mares (8 to 9 yr of age; 457 to 579 kg BW) were fed Bermudagrass hay and a corn/cottonseed hull-based supplement formulated to contain either 100% (control) or 50% (restricted) of the protein and(or) energy requirements for maintenance in a 2 x 2 factorial arrangement of treatments. Daily measurements of intake, BW, and plasma hormones and metabolites were made for 33 d. Plasma glucose, insulin, NEFA, and urea N were measured in hourly samples drawn on d 27, and parallel with an i.v. glucose tolerance test (IVGTT) and epinephrine challenge on d 29. Energy restriction increased daily NEFA concentrations (P < .001) and urea N (P = .013), whereas protein restriction decreased (P = .002) urea N concentrations. These effects of protein and energy restriction occurred within 24 h and were consistent (day effect, P > .1) throughout the remaining 24 d. Normal meal consumption elevated plasma glucose, insulin, and urea N concentrations (time effect, P < .08). Plasma NEFA concentrations did not change after feeding in mares fed control energy, but decreased in mares fed restricted energy (energy x time interaction, P = .005). After IVGTT, areas under the curve for plasma glucose and insulin were smaller in mares fed restricted protein (P < .05), whereas glucose area was larger in mares fed restricted energy (P = .009). After epinephrine injection, energy restriction increased the initial magnitude of the NEFA response, but after 50 min, reduced plasma NEFA below pre-injection concentrations (energy x time interaction, P = .06).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Feed deprivation of mares: plasma metabolite and hormonal concentrations and responses to exercise.

Twelve light horse mares were fed a control diet that provided 100% of their maintenance protein and energy requirements for 7 d and were then either continued on the control diet or totally deprived of feed (with access to water) for 3 d . Plasma samples were drawn twice daily throughout the experiment, at 15-min intervals for 9 h beginning 45 h after feed removal, and at 10-min intervals around an exercise bout beginning 73 h after feed removal. Feed deprivation increased (P < or = .06) whole blood beta-hydroxybutyrate and plasma NEFA, urea N, L-lactate, and glucagon concentrations, decreased (P = .02) IGF-I concentrations, and did not change (P > .1) plasma glucose insulin, prolactin, triiodothyronine, and thyroxine concentrations. Exercise increased (P < .05) plasma NEFA, prolactin, and growth hormone (GH) concentrations in all mares. Plasma NEFA concentrations increased (P < .001) after exercise and remained increased in fed mares, but rapidly decreased in deprived mares (time x diet interaction, P = .006). Plasma glucose concentrations following exercise increased in deprived mares but decreased in fed mares (time x diet interaction, P = .07). The plasma prolactin response after exercise also differed between groups (P = .09). Feed-deprived mares had greater (P = .02) plasma GH concentrations before exercise (73 h after feed withdrawal) and had a greater (P < .001) GH peak at 10 min after initiation of exercise. The increase in secretion rate o GH due to feed deprivation in these mares was similar to that reported for other domestic species but was not nearly as great in magnitude.

Animals↗
PubMed1995

Dietary protein and(or) energy restriction in mares: plasma growth hormone, IGF-I, prolactin, cortisol, and thyroid hormone responses to feeding, glucose, and epinephrine.

Sixteen light horse mares were fed diets of bermudagrass hay and a corn/cottonseed hull-based supplement formulated to contain either 100% (control) or 50% (restricted) of the protein and(or) energy requirements for maintenance in a 2 x 2 factorial arrangement of treatments. Plasma IGF-I, prolactin, cortisol, triiodothyronine, and thyroxine were monitored for 33 d. On the 27th d, frequent blood samples were drawn throughout the day for the measurement of growth hormone (GH), and on the 29th d, an epinephrine challenge and an i.v. glucose tolerance test (IVGTT) were performed in the morning and afternoon, respectively. Restriction of protein and(or) energy reduced (P < .001) plasma IGF-I concentrations within 24 h, and the effect persisted through the 24th d. Energy restriction decreased (P = .01) plasma cortisol concentrations, whereas thyroid hormones were not influenced (P > .1) by restriction of protein and(or) energy. Plasma prolactin concentrations were low throughout the experiment and after the IVGTT, but they increased (P = .003) after feeding. Protein restriction increased (P = .09) the occurrence of GH episodes during the 14-h feeding period on d 27; the greatest effect occurred in the mares restricted in both nutrients. In contrast, energy restriction reduced (P = .05) the GH response to epinephrine injection. We conclude that 1) protein deficiency in mares increases GH secretion, whereas energy restriction alone does not, 2) a deficiency in energy and(or) protein reduces IGF-I secretion, and 3) prolactin concentrations increase after feeding, even at a time of year when secretion rates are naturally low.

Animals↗
PubMed1994

Growth hormone and prolactin concentrations in plasma of horses: sex differences and the effects of acute exercise and administration of growth hormone-releasing hormone.

Three experiments were conducted to determine 1) the relationship between prolactin and growth hormone (GH) secretion in mares and the response to GH-releasing hormone (GHRH), 2) whether plasma GH and prolactin concentrations differed among mares, stallions, and geldings, and 3) whether sexual differences existed after administration of GHRH and acute exercise. In Exp. 1, 10-min blood samples were collected from 12 mares for 8 h, and GHRH (0, 45, 90, or 180 micrograms) was administered at 6 h. In Exp. 2, 15-min blood samples were collected for 4 h from 10 mares, stallions, and geldings. In Exp. 3, eight horses of each sexual status were administered GHRH at 0900; later that day, each horse was exercised for 5 min. Blood samples were collected every 10 min around each event. In Exp. 1, prolactin concentrations decreased (P < .01) over the 8-h period, and there was an average of 2.9 +/- .5 episodes of increased secretion during that time; there was no correlation between these episodes and those in GH secretion. Prolactin concentrations were not affected (P > .1) by GHRH. In Exp. 2, average concentrations of GH were 2.4, 8.6, and 8.5 ng/mL for mares, stallions, and geldings, respectively; males differed from females (P < .05). Stallions and geldings had more (P < .05) peaks in GH concentrations and greater (P < .05) amplitude of peaks than mares. In contrast, prolactin concentrations were greater (P < .02) in mares and stallions than in geldings. In Exp. 3, GH response to GHRH was greater (P < .03) in stallions than in mares or geldings.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1994

Changes in concentrations of hormones, metabolites, and amino acids in plasma of adult horses relative to overnight feed deprivation followed by a pellet-hay meal fed at noon.

Experiment 1 was conducted to characterize the concentrations of prolactin, growth hormone (GH), cortisol, insulin, glucagon, glucose, nonesterified fatty acids (NEFA), urea N, and 10 indispensable amino acids in the plasma of mares (n = 8) and stallions (n = 8) during the last 4 h of a 19-h period of feed deprivation and for 8 h after a noon meal. Experiment 2 was similar to Exp. 1 except that only stallions (n = 8) were used, and they were either fed (n = 4) or not fed (n = 4) at noon in a 2 x 2 Latin square design conducted over two sampling days 7 d apart. In Exp. 1, increases (P < .01) after feeding were observed for plasma concentrations of prolactin, cortisol, insulin, glucagon, glucose, urea N, and all amino acids except methionine; NEFA concentrations decreased (P < .01) after feeding. Episodic increases in GH concentrations were observed for most horses but were not associated with either feeding or gender (P > .1). Plasma urea N concentrations were higher (P < .025) overall in stallions than in mares, and the rise in prolactin concentrations after feeding was greater (P < .01) in stallions than in mares. In Exp. 2, meal-associated increases (P < .01) were observed for plasma concentrations of prolactin, insulin, glucagon, and glucose; NEFA concentrations decreased (P < .01). Except for cortisol, no hormone or metabolite varied with time across days when the stallions were not fed (P > .1), indicating that there was no inherent diurnal or feeding schedule-associated fluctuations in their concentrations. Cortisol concentrations varied (P < .02) over time but did not differ (P > .1) between fed and nonfed stallions. Again, GH concentrations were episodic but did not differ (P > .1) between fed and nonfed stallions. The lack of feeding effects on GH secretion in horses is similar to the response in pigs but differs from that in ruminants, in which GH concentrations generally decline after feeding.

Amino Acids↗
PubMed1994

Plasma concentrations of prolactin, glucose, insulin, urea nitrogen, and total amino acids in stallions after ingestion of feed or gastric administration of feed components.

Concentrations of prolactin, glucose, insulin, urea N, and total amino acids in plasma of stallions after ingestion of pelleted feed were compared to those after direct gastric administration of water, NaCl, egg albumin, or corn starch (Exp. 1) or water, egg albumin, hydrolyzed casein (Amicase), or a mixture of indispensable amino acids (Exp. 2). Stallions were fed once daily (75% pellet and 25% hay) at 1500 for 30 d. On d 22, 24, 26, 28, and 30, blood samples were collected every 30 min from 1 h before through 4 h after treatment, which occurred at 1100. In Exp. 1, there was a positive secretory response for prolactin (P = .013) only after the meal. Positive glucose and insulin responses were observed after the meal (P < .055) and after gastric administration of corn starch (P < .001). Total amino acids increased (P = .008) only after the meal. In Exp. 2, a positive prolactin response (P < .001) occurred after the meal and a negative response (P = .023) after administration of water; administration of Amicase increased (P = .061) prolactin concentrations after a 2.5-h delay. Positive responses were observed for glucose, insulin, and total amino acids after the meal (P < .001) and after administration of Amicase or the amino acid mixture (P < .026). Positive urea N responses were observed after administration of Amicase and the amino acid mixture (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1992

Growth hormone in mares and stallions: pulsatile secretion, response to growth hormone-releasing hormone, and effects of exercise, sexual stimulation, and pharmacological agents.

Short-term patterns of growth hormone (GH) secretion and factors affecting it were studied in mares and stallions. In Exp. 1, hourly blood samples were collected from three mares and three stallions in summer and winter. Although GH concentrations varied in a pulsatile manner in all horses, there was no effect of sex or season (P greater than .1) on plasma GH concentrations and no indication of a diurnal pattern of GH secretion. In Exp. 2, 10-min blood samples were drawn for 8 h from 12 mares; after 6 h, porcine GH-releasing hormone (GHRH) was administered i.v. at 0, 45, 90, or 180 micrograms/mare (three mares per dose). Pulsatile secretion of GH occurred in all mares and averaged 2.4 +/- .3 peaks/6 h; amplitudes were variable and ranged from 2.6 to 74.4 ng/mL. Eight of nine mares responded within 20 min to GHRH injection, but there was no difference (P greater than .1) among the three doses tested. In Exp. 3, plasma GH concentrations in stallions increased (P less than .05) 8- to 10-fold after 5 min of acute physical exercise or exposure to an estrual mare. Restraint via a twitch (5 min) and epinephrine administration (3 mg i.v.) also increased (P less than .05) plasma GH concentrations by approximately fourfold. In Exp. 4 and 5, administration of either .4, 2, or 10 mg of thyrotropin-releasing hormone (TRH) or 100 or 500 mg of sulpiride (a dopamine receptor antagonist) increased (P less than .01) plasma prolactin concentrations but had no effect (P greater than .1) on GH concentrations during the same period of time.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Toxic epidermal necrolysis.

To improve the past statistics of high mortality and morbidity in patients with TEN, definitive measures are required. Early referral and transfer to a burn center and withholding or withdrawing steroid therapy are two crucial factors. Therapeutic goals must be directed toward promotion of wound healing; correction of fluid and electrolyte abnormalities; provision of pulmonary care; prevention or correction of thermal disturbances; control of pain; prevention of physiologic and psychologic disabilities, which may hamper the return to activities of daily living; and above all, prevention of sepsis through protective isolation and refraining from use of invasive lines and catheters. Wound healing is best supported through gentle cleansing with physiologic saline; application of biologic or synthetic skin dressings or silver nitrate dressings; hourly eye care; nutritional support; and avoidance of infection or further injury of the dermis. Collaboration and teamwork by all health care providers are essential, and the quality of intensive nursing care makes the critical difference.

Clinical Protocols↗
PubMed1989

Furosemide: update on a commonly used drug.

Because of its efficacy, IV furosemide has become a common medication administered to the critically ill adult. It is capable of causing serious complications if given without caution, without prior assessment of the patient's clinical status, or without careful monitoring of response to therapy. Furosemide has the potential to cause problems that are more than fluid and electrolyte imbalances. The nurse must be aware of toxic effects and how to minimize them when giving higher doses and, in renal failure. It is imperative for a patient's progress that his or her nurses have a knowledgeable and respectful attitude toward the drugs they administer.

Critical Care↗
PubMedDate not supplied

Inline closed-system suctioning: a research analysis.

Numerous studies on closed-system suctioning have been conducted including projects evaluating hyperoxygenation, influence of airway pressures and ventilation mode, efficiency in secretion removal, and autocontamination. These authors critique past research projects and propose directions for nursing practice and future research. By analyzing these projects, you can develop current practice standards to improve patient outcomes.

Clinical Nursing Research↗