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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1081

Altered insemination timing improves pregnancy rates after a CO-Synch + progesterone insert protocol

Dobbins, Casey January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Jeffrey S. Stevenson / Our objective was to determine the optimal time to inseminate artificially cows following the standard CO-Synch protocol that also included a progesterone-releasing intravaginal controlled internal drug release (CIDR) insert. Lactating females from 3 Kansas locations were utilized. Crossbred Angus cows (n = 212) from the Agriculture Research Center in Hays (ARCH; location 1); Angus-Hereford crossbred cows (n = 249) from the Kansas State University Cow-Calf Unit (location 2); and purebred Angus, Hereford, and Simmental cows (n = 144) from the Kansas State University Purebred Beef Unit (location 3) were used in this study. Cows within each location were blocked by parity and assigned randomly within blocks to be artificially inseminated (AI) at 4 different times after the PGF2[Alpha] injection of the protocol: 48, 56, 64, or 72 h. Pregnancy diagnosis occurred at 32 and 63 d after insemination. Blood samples were collected 9 to 10 d and just before the first GnRH injection. Radioimmunoassays were performed on the blood sera samples to determine progesterone concentrations. Progesterone concentrations determined that approximately 60% of cows were cycling at the initiation of the study. A difference in cyclicity was observed with regards to age as well as body condition score. Pregnancies per AI (P/AI) at d 32 varied according to location and cycling status. Pregnancy loss between d 32 and 63 also was greatest for cows inseminated at 48 and 72 h. As pregnancy rates at d 63 increased with the 56- and 64-h treatments, pregnancy loss decreased. A significant difference in calving interval was detected among treatments, the shortest calving interval at 56 h. Results indicated that in most situations, the 56- and 64-h treatments presented the most desirable outcomes. The 56-h treatment presented the greatest number of P/AI for younger cows (≤ 3 yr), but for older cows, inseminations anytime 56 h or later produced the most P/AI. Overall pregnancy rates at d 63 were greatest for the 56-h treatment, with the fewest pregnancy losses. Given the interactions that seem to exist among location, cycling status, and age, further work is necessary to better define these relationships with the applied protocol.
1082

Analgesic efficacy of sodium salicylate in an amphotericin B induced bovine synovitis-arthritis model

Kotschwar, Jamie Lee January 1900 (has links)
Master of Science / Department of Clinical Sciences / Mike D. Apley / Lameness is a common, costly, and painful affliction in cattle at all production levels. There are currently no compounds specifically approved for analgesia in cattle in the United States. We hypothesized that intra-articular amphotericin B produces a controlled, transient synovitis-arthritis in cattle and that this model would allow characterization of the analgesic effects of intravenous sodium salicylate. This study examined the efficacy of sodium salicylate for providing analgesia in an amphotericin B-induced bovine synovitis/arthritis model utilizing ten male Holstein calves, 4-6 months old, and weighing approximately 250 kg. The study used a repeated measures partial cross-over design with 2 phases consisting of 3 treatment periods within each phase. Calves were blocked by weight and randomly assigned to sodium salicylate (50mg/kg intravenously) or placebo group for phase 1. In period 1, lameness induction was simulated with a needle-prick of the coronary band, followed by drug or placebo administration. At predetermined timepoints, serial blood samples for cortisol and salicylate concentrations, electrodermal activity measurements, heart rates, and pressure mat data were collected. Visual lameness scores were recorded by a blinded observer. In period 2, lameness was induced with injection of amphotericin B into the distal interphalangeal joint followed by drug or placebo administration with sample collection as previously described. In period 3, drug or placebo was administered to the respective calves with sample collection. After a 10-day washout, Phase 2 was conducted with treatments crossed over between groups. Cortisol and salicylate samples were analyzed by competitive chemiluminescent immunoassay and fluorescence polarization immunoassay, respectively. The pharmacokinetic data were analyzed using compartmental analysis. Mean intravenous salicylate apparent volume of distribution (V[subscript]d) was 0.2 ± 0.005 L/kg, total body clearance (CL[subscript]B) was 4.3 ± 0.2 mL/min*kg, and elimination half life (T[subscript]1/2 el) was 36.9 ± 1.2 minutes. The repeated measures data were analyzed based on a univariate split-plot approach with a random effects-mixed model. Differences in stance phase duration and serum cortisol concentration values were seen between both periods and treatment group*periods; differences in heart rate, contact surface area, and contact pressure values were seen between periods, suggesting that our lameness model was effective. No differences were seen between treatment groups. When analyzed by visual lameness score, differences were seen in heart rate, contact surface area, contact pressure, and cortisol concentrations. Area under the time-effect curves, determined using the trapezoidal rule, had results similar to the repeated measures data, except for a difference in period for electrodermal activity. This amphoterecin B-induced synovitis/arthritis model is a useful tool for studying changes associated with lameness in cattle. Sodium salicylate was not effective in providing analgesia following lameness.
1083

Blood cell alterations in diabetes: Implications for ischemia-reperfusion injury in the diabetic heart

Hokama, Jason Yoshitsune January 1999 (has links)
Diabetes is now considered a major risk factor for cardiovascular disease, particularly ischemic heart disease. Although restoration of coronary blood flow is prudent in order to salvage the region of the myocardium at risk, reperfusion is also associated with an additional injury to the heart. This is known as myocardial ischemia-reperfusion (I-R) injury. The diabetic heart appears to be more susceptible to I-R injury compared to non-diabetic hearts when blood is used as the perfusate suggesting that components within diabetic blood may play a role in exacerbating the damage to the diabetic heart upon reperfusion. In a series of experiments, we tested the hypothesis that leukocytes are retained in the coronary microcirculation to a significant extent early in reperfusion following ischemia. We also examined if diabetic PMNs are hyperactivated, and are able to respond to exogenous inflammatory stimuli. Since diabetic blood is known to be hypercoagulable, we tested the hypothesis that platelet activation adhesion protein expression is increased in diabetic blood. Finally, we examined if platelet-PMN interactions are increased in diabetic blood. Our results indicate that, early in reperfusion following ischemia, leukocyte retention in the coronary capillaries and post-capillary venules is significantly increased in diabetic hearts compared to non-diabetic hearts. Our findings also indicate that PMNs from diabetics are hyperactivated compared to nondiabetic PMNs suggesting that, once sequestered, PMNs in the diabetic coronary microcirculation are able to initiate an exaggerated inflammatory response, which may exacerbate the reperfusion injury. We also found that platelet adhesion protein expression was enhanced in diabetics, an effect that was partially attenuated by aspirin usage. Platelet-PMN conjugate formation was increased in diabetic blood and appeared to enhance ROS production in diabetic PMNs since blockade of these aggregates attenuated PMN ROS production in diabetic blood. The results from these experiments indicate that both hyperactivated PMNs and platelets in diabetic blood likely contribute to exacerbated ischemia-reperfusion injury in the diabetic heart. Once the mechanisms of myocardial reperfusion injury in diabetes are known, therapeutic interventions can be introduced with the hope of attenuating the increased morbidity and mortality associated with ischemic heart disease in the diabetic population.
1084

Orthostatic blood pressure and heart rate responses after coronary artery bypass graft surgery

Lester, Arnette Sandland, 1952- January 1990 (has links)
A quasi-experimental study was conducted to compare preoperative and postoperative postural responses to position change. A convenience sample of 30 men and women admitted for elective coronary artery bypass graft (CABG) surgery performed supine to sitting and supine to standing position changes prior to surgery and on postoperative day two or three. An ANOVA with repeated measures compared the responses of systolic blood pressure, diastolic blood pressure and heart rate. Systolic blood pressure exhibited a significant change from preoperative to postoperative measurements. Diastolic blood pressure remained the same; heart rate changed over time, but no significant preoperative to postoperative changes occurred. Comparison of normotensive and hypertensive subjects revealed reduced postoperative responsiveness in the hypertensive subjects for systolic blood pressure and heart rate. Nurses caring for postoperative CABG patients should anticipate a reduction in blood pressure and an increase in heart rate upon standing.
1085

Reticuloendothelial clearance and gastrointestinal absorption of polystyrene latex particles: Possible applications to the external scanning of tumors

Reynolds, William David, 1948- January 1990 (has links)
The use of 153Sm-incorporated polystyrene latex particles for the external image scanning of tumors was simulated in four murine strains. Reticuloendothelial blood clearance and tissue localization of 0.5 mum and 1.0 mum fluorescent PSL was evaluated in RE-competent and RE-depressed mice following IV injection and oral particle administration. Intravenous injection of PSL revealed differences in blood clearance rates and tissue distribution patterns with respect to strain and particle size; an explanation based on genetic strain derivation is offered. RE depression in the Balb/c resulted in higher circulating blood levels of both particle sizes without affecting tissue distribution patterns; the use of dissimilarly sized particles for blocking and testing resulted in dramatic decreases in organ PSL concentrations and alterations in apparent kinetic rate constants. Balb/c blood levels of orally administered particles were increased and remained temporally constant while tissue concentrations were generally lower than IV-injected levels.
1086

Influence of exercise intensity and nasal flow resistance on activities of human nasal dilator muscles

Connel, Diane Carol, 1962- January 1992 (has links)
Ten healthy subjects exercised on a cycle ergometer at 60, 120, and 150-180 W while breathing nasally. Nasal inspiratory flow, nasal dilator muscle (alae nasi; A.N.) EMG activities, and alveolar CO₂ and O₂ were measured at rest and at each work rate. On separate days six of the subjects exercised at 30-60, and 60-120 W while nasal airway resistance was measured by anterior rhinomanometry. In both protocols, 12-15 breaths of a He:O₂ (79:21%) gas mixture were substituted surreptitiously for air under each condition. He:O₂ breathing resulted in a decrease in flow turbulence and intranasal pressure, and therefore, resistance, as indicated by lower calculated Reynold's numbers. He:O₂ evoked an increase in nasal inspiratory flow, and reductions in nasal pressure and A.N. EMG activities (25-50%) at each work rate. These results suggest that A.N. EMG during exercise is controlled by increases in intranasal pressure, not by nasal flow. Thus, the data suggest that sensory information from pressure sensitive nasal receptors in the nasal lumen serve to modulate A.N. EMG activities during exercise.
1087

Vitamin E turnover in cultured pulmonary alveolar macrophages

Hoeger, Glenn Charles, 1962- January 1992 (has links)
Vitamin E (α-TH), the primary lipid soluble antioxidant, can protect tissues from oxidative insult. Oxidant-producing pulmonary alveolar macrophages (PAM), may depend on α-TH to prevent oxidative damage. α-TH levels in cultured PAM declined rapidly during the first 12-18 hours in culture. Approximately 60% of the decrease was detected as unoxidized alpha-TH released to RPMI 1640 (containing 5% fetal bovine serum (FBS)) culture medium. α-TH was not detected in serum-free Ham's F12 medium. PAM appeared to reabsorb α-TH from the medium. PAM activation with phorbol myristate acetate (PMA) did not affect cellular α-TH depletion. However, the amount of α-TH detected in the medium of PMA treated cultures was only 50% of that detected in medium from untreated controls. Inhibition of superoxide production with iodoacetate had no effect on cellular depletion kinetics, however medium α-TH levels were still 50% of controls. Inhibition of nitric oxide, synthesis appeared to have no effect on α-TH status.
1088

Studies on mechanisms of delayed puberty in female rats effected by dietary eicosapentaenoic acid

Zhang, Zhao, 1960- January 1992 (has links)
Marine oils contain eicosapentaenoic acid, a fatty acid that competes for cyclooxygenase and reduces the synthesis of dienoic prostanoids including prostaglandin E2 (PGE2). Since PGE2 plays an important role in the release of hypothalamic GnRH and the maturation of ovarian follicles and ova release, it was postulated that a diet containing fish oil (FO) would delay first ovulation through inhibitory effects on GnRH release, follicle development and ovulation. Immature female Sprague-Dawley rats were fed a FO diet ad libitum. Controls were pair-fed an identical diet with the substitution of safflower oil. The age of the FO-fed rats was significantly increased at first estrus, and first ovulation was either delayed or inhibited. Preoptic area/hypothalamic and ovarian PGE2 levels were reduced by FO feeding whereas hypothalamic GnRH was significantly increased. A FO-containing diet may delay the onset of puberty through attenuation of preovulatory GnRH release and local impairment of the ovulatory process.
1089

Evolution of cytochrome c oxidase subunit 4 in relation to hypoxia

Kocha, Katrinka Maria 21 January 2013 (has links)
Cytochrome c oxidase (COX) is complex IV of the electron transport system, and catalyzes the reduction of molecular oxygen to water. It possesses ten nuclear-encoded subunits, the largest of which is COX4. Bayesian analysis suggests the isoform pair for this subunit arose early in vertebrate evolution, and tissue distribution of the COX4 paralogs is similar in mammals and teleosts: COX4-1 is ubiquitously transcribed while COX4-2 is present in large amounts only in brain and respiratory tissue. This subunit is of interest due to its apparent sensitivity to oxygen. During hypoxia, transcription switches from COX4-1 to COX4-2 in some mammalian tissues. However, questions remain about the regulation of this response as well as its pervasiveness across vertebrates. I investigated these uncertainties by measuring the transcriptional response of the COX4 paralogs to hypoxia in a variety of vertebrate models, and assessing the hypoxic induction of putative oxygen-responsive elements (HRE1, HRE2, and ORE) from candidate vertebrate species in a transfection experiment. I also examined the conservation of key elements of the COX4-2 gene and polypeptide in vertebrates. It was found that the hypoxia-responsiveness of COX4-2 may not be vital to the cellular response to hypoxia. COX4-1 transcripts remained in excess during hypoxia in all of the vertebrate models used with the exception of western painted turtle (Chrysemys picta), where COX4-2 transcripts remained in excess during control and hypoxic treatments. Only the HRE2 element from human COX4-2 was activated with hypoxic exposure, yet this along with the other features of the gene and polypeptide were not well conserved across mammals, and nearly absent outside of this lineage. These results provide evidence that COX4-2 may respond to hypoxia in only select few mammalian tissues, or that the function of this gene is not related to the cellular hypoxic response. / Thesis (Master, Biology) -- Queen's University, 2012-11-25 20:51:59.419
1090

Core temperature measurement during exercise: Comparison of an ingestible capsule with rectal and esophageal thermistors

Unknown Date (has links)
The purpose of this study was to compare core temperature measurements obtained from the $\rm CorTemp\sp{tm}$ ingestible capsule with those obtained simultaneously from rectal and esophageal probes in order to determine whether the capsule could be considered a suitable replacement for either of the other two methods. Comparisons were made in 20 subjects during rest, exercise (60 min of cycling at 50% HRR), and recovery on two occasions, spaced 16 hours apart. / Bland-Altman plots indicated that levels of agreement between capsules and esophageal and rectal probes exceeded the pre-determined level of acceptability $({\pm}0.5\sp\circ\rm C)$ at both +1 hr and +16 hrs for all three test conditions (rest, exercise, and recovery). During exercise, limits of agreement for the capsule v esophageal comparison extended from ${-}0.73\sp\circ$ to ${+}0.71\sp\circ\rm C$ at +1 hr, and from ${-}0.86\sp\circ$ to ${+}1.14\sp\circ\rm C$ at +16 hrs. For the capsule v rectal comparisons, limits extended from ${-}0.36\sp\circ$ to ${+}0.72\sp\circ\rm C$ at +1 hr and from ${-}0.41\sp\circ$ to ${+}0.91\sp\circ\rm C$ at +16 hrs. / The lack of acceptable agreement was due to the combination of bias, or mean differences between the methods, and to excessive variability among the differences between the methods. Of these two factors, the excessive variability contributed more to the lack of agreement than did the mean differences between methods. Causes for the excessive variability appear to be related to a lack of repeatability among each of the devices individually, to different rates of change in core temperature at the different sites, and to the mobility of the capsules within the gastrointestinal tract. / Within the scope and limitations of this study, it was concluded that the $\rm CorTemp\sp{tm}$ ingestible capsule remains unproven as a suitable replacement for rectal or esophageal probes for the measurement of core temperature. Although the capsules can accurately reflect temperatures in the controlled environment of a waterbath, once situated within the human gastrointestinal tract an unacceptable level of agreement with rectal and esophageal probes was observed. / Source: Dissertation Abstracts International, Volume: 55-09, Section: B, page: 3756. / Major Professor: Robert J. Moffatt. / Thesis (Ph.D.)--The Florida State University, 1994.

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