To evaluate the effect of two different cooling systems on production, physiological, and hormonal responses, 37 Holstein and 26 Brown Swiss dairy cows were allotted to three treatments. A control group of cows had access to only shade (C). A second group was cooled with spray and fan (S/F) and the third group was under an evaporative cooling system called Korral Kool&circR; (KK). The trial lasted from May to September with a daily maximum temperature-humidity index from 73 to 85. Milk production differences in Holstein cows were significantly increased by KK and S/F. No treatment differences in milk production were observed in Brown Swiss cows. Protein percentages were higher in C group compared to Korral Kool group only in Brown Swiss cows, while fat percentage were similar among treatments in Holstein cows. Rectal temperatures and respiration rates of the C group were higher than S/F and KK in both Holstein and Brown Swiss cows. Triiodothyronine levels in milk were significantly higher in KK group compared to S/F and C groups, while cortisol levels were lower in C group than S/F and KK. Similar differences were observed in body weight and body condition score changes between treatments in Holstein or Brown Swiss cows. Pregnancy rate was increased in the groups under the cooling systems in Holstein cows, however this effect was not observed in Brown Swiss cows where C group had a higher pregnancy rate than cooled groups. The cows under cooling systems spend more time eating and outside of the shade in the early afternoon (12:00 to 15:00) than control group. Cows injected with bST (bovine somatotropin) increased milk yield significantly only in Brown Swiss cows, whereas respiration rates were increased in both breeds by bST but rectal temperatures were similar between bST and non-bST cows. These results demonstrate that both cooling systems are an alternative to increase productive and reproductive performance and comfort of Holstein cows during summer in hot-dry climates. The physiological responses of Brown Swiss cows indicated a better adaptation to a hot climate, however their milk production was lower than in Holstein cows.

The insect neuropeptide eclosion hormone (EH) interacts in a positive feedback loop with two other hormones to trigger ecdysis behavior in the hawkmoth, Manduca sexta. There is also evidence that EH may act at other targets to coordinate physiological changes that must occur with ecdysis. Recently, the use of an antibody that recognizes the second messenger cyclic guanosine monophosphate (cGMP) in fixed tissue has allowed us to identify a novel target for EH in the proximal region of the abdominal transverse nerves of Manduca. Here we show that a significant increase in cGMP can be measured in vivo in the transverse nerves at a time when EH is normally released in the animal. Furthermore, in vitro experiments revealed that the ability of the transverse nerve to respond to EH is abruptly lost after the pupal ecdysis. Finally, it was found that up to 40% of the cGMP produced by the STNR in response to EH is exported out of the cells in probenecid-sensitive manner, and there is a significant increase in the hemolymph concentration of cGMP at the time of pupal ecdysis. Microscopic examination of transverse nerve sections revealed that the cGMP-positive filaments are the processes of intrinsic cells, and the area in which they reside was named the subtransverse nerve region (STNR). Ultrastructurally, the cells of the STNR fall into two groups: large-granule containing cells and ribosome rich cells. EH-stimulated cGMP immunoreactivity appears to be restricted to the ribosome rich cells. The discrete STNRs of the abdominal transverse nerves can be identified as early as the first instar and probably originates embryologically. After the time of wandering in the last instar, the cells of the STNR begin to divide and spread in a flat sheet between the transverse and dorsal nerves of each ganglion, and are positive for myosin by pupal stage 8. These STNR-derived cells appear to form the ventral diaphragm muscles of the adult. This is the first evidence in any insect that a reservoir of myoblasts exists in close proximity to the transverse nerves and the first evidence that myoblasts are a target for EH.

Small amounts of nitric oxide are released by endothelial cells under normal physiological conditions whereas, excess amounts are released under inflammatory conditions. Histamine is one of the inflammatory mediators that increases venular permeability to water and proteins. However, the increase in venular permeability that is caused by histamine is transient, and recovers to control levels even with histamine present. The permeability recovery phenomenon suggests a control mechanism that limits the histamine insult. This dissertation research was to investigate the role of nitric oxide in this recovery period after histamine injury. The research was performed to test the hypothesis that nitric oxide is the physiological molecule that counteracts the destructive effect of histamine. Therefore, the role was investigated by using a nitric oxide synthase inhibitor to suppress the production of nitric oxide during the recovery period. The rat mesenteric microvascular network was suffused with histamine for three minutes followed by fifteen minutes of nitric oxide synthase inhibition. It was found that inhibition of nitric oxide production during the recovery period exaggerated the histamine induced venular leaks, and caused further degranulation of mast cells that was stimulated with histamine suffusion. Nitric oxide presence during the recovery period attenuated venular leaks so they fell toward control levels, and prevented further mast cell degranulation. Availability of nitric oxide, via a nitric oxide donor, in venules before histamine suffusion prevented these venules against histamine induced leakage, but it had little effect on mast cell degranulation. An electron microscopic study was performed to further investigate the role of nitric oxide in the recovery period and to test the hypothesis that nitric oxide will be localized to the cell membrane. The immuno-electron microscopic results demonstrated that both number of sites and location of nitric oxide synthase were affected by histamine treatment. There was relocalization of nitric oxide synthase onto the venular endothelia cell surface. Therefore, we concluded that nitric oxide has a direct effect on venular endothelial cells to reduce venular leaks through regulatory mechanism(s) which may involve intercellular junctions and the cytoskeleton.

The human neuromuscular system undergoes substantial reorganization after the age of 60 years. Many of these processes have significant functional consequences on the ability of old adults to perform normal activities of daily living. This thesis focuses on the function of an intrinsic hand muscle, the first dorsal interosseous, which is located between the thumb and index finger and is solely responsible for abduction of the index finger about the first metacarpophalangeal joint. The first dorsal interosseous also contributes to flexion of the index finger, and is especially important to the precision pinch grip. When an individual is instructed to exert a submaximal, constant abduction force with the index finger, the force is not constant, but varies about an average value. The magnitude of the force fluctuations is greater for old subjects compared with young subjects. Previous studies have focused on age-related differences in the size of individual motor units as a potential mechanism underlying the reduced steadiness. The purpose of this thesis was to examine the effects of agonist antagonist coactivation, motor unit discharge variability, and light- and heavy-load strength training on the ability of young and old adults to exert steady muscle forces during slow finger movements. The results indicate that the recruitment and modulation of the discharge rate of motor units changes with age, which contributes to the decline in movement capabilities.

Cardiac Vagal Tone (CVT) has been shown to predict a number of important emotional and behavioral outcomes. Although CVT has been proposed as an index of emotion regulation (Porges et al., 1994), little research to date has sought to explore the link between CVT and broader conceptual variables relating to personality and self-regulation. The present study measured CVT (using respiratory sinus arrhythmia) across five-minute baseline, suppression, and recovery periods in participants (n = 102) who had previously completed a short form of the Marlowe-Crowne Social Desirability Scale and the Openness to Experience subscale of the NEO-PI. Response latencies for Ideal and Ought self-guides (Higgins, 1997) were collected in order to assess the relationship between self-regulatory style and CVT. Defensiveness, non-Openness, and increased Ought-self accessibility were hypothesized to predict reduced CVT, and reduced capacity to suppress of CVT. Data revealed that participants suppressed CVT during a serial counting task, and higher CVT was predicted by lower social anxiety scores. Defensiveness predicted generally lower mean CVT scores across conditions, but no difference in the degree of change for CVT from baseline to suppression, or suppression to recovery. The relationship between defensiveness and mean CVT levels was moderated by gender, with defensiveness predicting significant differences in CVT for men only (higher defensiveness correlating to lower CVT). Neither Openness nor self-guide accessibility was related to CVT levels, and defensiveness did not moderate the relationship between CVT and Openness. Supplemental analyses suggest that behavioral inhibition scores (BIS) may interact with gender in predicting CVT, with low-BIS men exhibiting higher CVT than high-BIS men, and low- and high-BIS women showing an inverted (but non-significant) pattern. The results imply that CVT may be a more conceptually distinct variable than had been predicted, but also raise questions about the nature of defensiveness for men and women, and the validity of self-report personality measures.

The present study explored possible relations between respiratory and laryngeal function associated with changes in lung volume level during phonation. Respiratory, acoustic, aerodynamic, electroglottographic, and videostroboscopic measures were obtained simultaneously for 14 normal female speakers as they sustained vowels and syllable repetitions throughout the vital capacity. Statistical analyses compared group performances between (a) high and mid lung volumes; and (b) mid and low lung volume levels. Significant differences were found for (1) vertical laryngeal position (VLP); (2) amplitude of vocal fold vibration; (3) minimum flow; (4) degree of glottal closure, and (5) degree of laryngeal compression. Results indicated that during phonation at high lung volumes the larynx displays an overall "more dilated" configuration with a lower position in the neck, larger amplitudes of vocal fold vibration and larger posterior glottal gaps during the closed phase of vocal fold vibration. Conversely, during phonation at low lung volumes the larynx seems to adopt a more constricted configuration, with a more elevated position, smaller amplitudes of vocal fold vibration, more complete glottal closure during the closed phase of vocal fold vibration, and increased degree of compression. Results also indicated that while some vocal function measures displayed different absolute values for sustained vowels as compared to syllable repetitions, the patterns of change were similar for both speech tasks. Individual subject data reflected alternative patterns of laryngeal behavior for achieving the speech tasks. The results were interpreted as evidence that laryngeal function during voice production is clearly influenced by the lung volume at which phonation is produced. Possible underlying physiological mechanisms are discussed. These findings contribute to better understanding of the normal vocal mechanism when phonation is produced outside of the normal mid-range of lung volumes typically used in conversational speech.

Experiments were conducted to determine effects of feeding whole cottonseed (WCS), expander solvent cottonseed meal (CSM), or a combination of these, as well as other factors on blood gossypol concentrations in cattle. In an 84 d trial, lactating cows were fed zero, 900 or 1800 ppm total gossypol (TG) in diets from WCS and/or CSM. Plasma gossypol (PG) in cows receiving 1800 ppm TG plateaued at 3.28 μg/ml after 28 d. However, by 28 d, erythrocyte fragility increased for cows receiving WCS diets. Plasma chemistry, vitamin A, body temperatures, and respiration rates were within normal ranges. Serum vitamin E levels increased with cottonseed in diets. Milk yield and FCM higher (P < 0.05) for cows fed 13.5% WCS and 7% CSM diet than controls. Feed efficiency and milk fat and protein percentages were not influenced by diets. In another study, young Holstein steers were fed diets during five consecutive treatment periods of 28 d each. The following was shown: (1) A basal diet with 15% Upland WCS resulted in average TG intakes of 9.08 g/d. (2) When varying concentrations of dietary iron (5 treatments) were fed with 15% WCS, PG and plasma total gossypol response (PG/TG intake) decreased as iron in diets increased. (3) Five diets with 15% cottonseed in the whole, cracked, roasted, roasted and cracked, or extruded forms showed that roasting or excluding WCS reduced FG in seed up to 86%. The PG concentration was higher (P < 0.05) for the whole and cracked diets, but plasma total gossypol response (PTGR) increased over controls for the cracked and roasted treatments. (4) When varying amounts of WCS and CSM (6 treatments) were fed up to 14 and 9% of the diet, respectively, PG concentration was higher (P for diets with 14% than 7% WCS. The PTGR was not affected by CSM supplementation for the 7% WCS treatments. (5) When feeding of four diets with 15% cottonseed as whole Upland, cracked Upland, whole Pima, or cracked Pima seed, PG and PTGR were higher for the Pima than Upland diets. Performance for the 28 d periods was not altered by treatments.

The use of materials for replacement or repair of biological tissue and organs has been attempted for thousands of years. Regardless of material used or site of implantation all biomedical materials elicit a foreign body response by the host characterized by the presence of macrophages and foreign body giant cells with the polymer for the duration of the implant. This inflammatory response is believed to be responsible for the lack of biocompatibility of implanted materials. Furthermore, each type of biomedical device suffers from specific problems that may lead to the ultimate failure of the implant. Synthetic polymeric vascular grafts fail primarily due to the inherent thrombogenecity of the material and anastomotic neointimal thickening. In an attempt to create a non-thrombogenic lining on the blood contacting surface of vascular implants, the promotion of an endothelial lining on the luminal surface of vascular grafts has been investigated. This can be accomplished by both artificial and natural mechanisms. Regardless, it is believed that the inflammatory response elicited by the implant influences the angiogenic mechanisms and neointimal thickening associated with the implant. The relationship between inflammation and angiogenesis associated with biomedical implants remains to be delineated. Studies in this dissertation attempt to determine this relationship by examining the inflammatory response and inflammatory cytokines released by cells associated with polymeric implants and how these bioactive molecules influence the angiogenic response. Furthermore, an advancing technology in vascular repair, endovascular grafts, was tested in two vascular models to assess the general healing characteristics, inflammatory response and the formation of blood vessels associated with the device. The results from these studies suggest that the inflammatory response plays a fundamental role in the formation of blood vessels around polymeric implants and neointimal thickening on the luminal surface of vascular implants. From these experiments a greater understanding of the healing response associated with vascular grafts has resulted.

The macroglomerular complex (MGC) in the antennal lobe of the sphinx moth Manduca sexta is the first brain region for processing sex-pheromonal information. How is the MGC is functionally organized, and how are chemical and physical features of the pheromone encoded by projection neurons (PNs) innervating the MGC (MGC-PNs). For some MGC-PNs with arborizations in the toroid, one of the two major glomeruli of the MGC, bombykal (a key pheromone component) can evoke a mixed (inhibitory/excitatory/inhibitory) response similar to that evoked by the pheromone blend. Likewise, for some neurons with arborizations in the cumulus, C-15 (a mimic of the second key component) can evoke a similar mixed response. The maximal pulse frequency encoded by these component-specific neurons was not increased in the presence of the blend, but seemed to arise through the convergence of two parallel pathways, one excitatory and one inhibitory, both activated by the same olfactory stimulus. Convergence of different synaptic pathways allowed MGC-PNs to resolve intermittent stimuli and thus to relay the temporal structure of the pheromonal signal to higher brain centers. In a subset of MGC-PNs that was excited by antennal stimulation with either of the two components (bombykal-C-15 cells, blend neurons), the ability to encode intermittent stimuli was improved when stimulating with the blend. The temporal character of the responses was dependent on the ratio of the two key components in the blend. Component-specific MGC-PNs responded over a range of increasing pheromone concentration with stronger inhibitory and excitatory postsynaptic potentials and more impulses but the responses were not affected by changing the blend ratio. Two basic response patterns emerged when the ipsilateral antennal flagellum was stimulated at different zones along its proximo-distal axis while the activity of MGC-PNs was recorded. A subset of neurons with broad receptive fields was excited regardless of the zone of the antenna stimulated, whereas another subset responded selectively to stimulation of the basal region of the antenna. A diverse array of MGC-PNs forms a heterogeneous group of parallel output channels that encode features of the pheromone signal that the moth is likely to encounter in the natural stimulus situation.

The studies presented in this dissertation were designed to test the hypothesis that embryonic N-acetyltransferase (NAT) acetylates 4-aminobiphenyl (4ABP), potentially affecting embryonic aromatic amine toxicity. NAT1 and NAT2 mRNAs were detected in C57BL6/J mice in gestational day (GD) 10 embryo/placental tissue, GD 15 embryo and GD 15 placenta tissue, and GD 18 extrahepatic embryonic tissue. Only NAT2 mRNA was detected in GD 18 hepatic tissue. NAT1 was not found in GD 18 or neonatal day (ND) 3 liver. NAT activity was present at all three gestational time points where NAT mRNA was detected. 4ABP NAT activity increased as gestation advanced. Activity at ND 4 was 1.5 fold higher than GD 10 tissue and 1.2 fold higher than GD 15. Neonatal hepatic tissue showed very little difference between ND 2 and ND 4. Preliminary kinetic constants were determined for GD 18 through ND 4. The average Km was 74 muM and the average Vmax was 0.78 nmol/min/mg. Finally, in vivo studies were conducted to determine if there was embryonic exposure to 4ABP or 4AABP. The amount of 4ABP in embryonic or placental tissue remained constant over the three time periods tested. While the level of 4AABP in the placenta did not change during gestation, the amount of 4AABP detected in the GD 18 embryonic tissue increased significantly over the other time points. 5-15% of 4ABP and 20-30% of 4AABP maternal blood levels were detected in the embryonic/placental tissue. Less than 0.03% to 0.06% of the maternal dose was found to have been converted to 4AABP in embryonic tissue. In summary, (1) NAT1 and NAT2 mRNAs were found in embryonic tissue; (2) functional NAT protein was present in the embryo; and (3) 4ABP and 4AABP were found in the embryo following maternal exposure to 4ABP. This suggests that embryonic NAT may contribute to the developmental toxicity of aromatic amines.