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Loyola, E. G., Rodriguez, M. H., Gonzalez, L., Arredondo, J. I., Bown, D. N., & Vaca, M. A. (1990). Effect of indoor residual spraying of DDT and bendiocarb on the feeding patterns of Anopheles pseudopunctipennis in Mexico. J Am Mosq Control Assoc, 6(4), 635–640.
Abstract: Intense and persistent use of DDT for malaria control has increased resistance and induced exophilic behavior of Anopheles pseudopunctipennis. An evaluation of bendiocarb and DDT to control this species in Sinaloa, Mexico, showed that, in spite of DDT-resistance, both insecticides produced similar effects. Feeding patterns were analyzed to explain these results. Resting mosquitoes were collected over the dry and wet seasons. Anophelines were tested in an ELISA to determine the source of the meals. The human blood index (HBI) ranged from 3.3 to 6.8% in DDT- and from 12.7 to 26.9% in bendiocarb-sprayed houses. Irritability and repellency in DDT-sprayed houses could explain the reduced HBI. In contrast, bendiocarb produced higher mortality. These effects could have affected different components of the vectorial capacity and similarly reduced malaria.
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Crans, W. J., McNelly, J., Schulze, T. L., & Main, A. (1986). Isolation of eastern equine encephalitis virus from Aedes sollicitans during an epizootic in southern New Jersey. J Am Mosq Control Assoc, 2(1), 68–72.
Abstract: Eastern equine encephalitis virus (EEE) was isolated from the salt marsh mosquito, Aedes sollicitans, collected from coastal areas of New Jersey on 3 occasions during the late summer and fall of 1982. The isolations were made at a time when local Culiseta melanura were either undergoing a population increase or exhibiting high levels of EEE virus. Although no human cases were reported during the epizootic period, the data lend support to the hypothesis that Ae. sollicitans is capable of functioning as an epidemic vector in the coastal areas of New Jersey where human cases of EEE have been most common.
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Mitchell, C. J., Darsie, R. F. J., Monath, T. P., Sabattini, M. S., & Daffner, J. (1985). The use of an animal-baited net trap for collecting mosquitoes during western equine encephalitis investigations in Argentina. J Am Mosq Control Assoc, 1(1), 43–47.
Abstract: A large net trap was used to sample mosquito populations attracted to horses at three sites each in Santa Fe and Rio Negro Provinces, Argentina, during the austral summer of 1984. These provinces, as well as others in Argentina, were affected by a severe epizootic of western equine encephalitis (WEE) during 1982-83. Totals of 2,752 and 6,929 mosquitoes were collected in Santa Fe and Rio Negro Provinces during five and three trap nights, respectively. Culex mosquitoes of the subgenus Culex were predominant (45.8% of total) in the Santa Fe collections, although Aedes albifasciatus also was prevalent (21.7%). The latter species was predominant (95.7% of total) in the Rio Negro collections. The mosquito fauna was less complex (minimum of 6 species) in Rio Negro Province as compared to Santa Fe Province (minimum of 18 species). The advantages of the net trap indicate that this trap can become a useful tool in arbovirus ecology studies in other areas.
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Hopkins, W. D., & Parr, L. A. (1998). Lateralized behavior and lymphocyte counts in chimpanzees (pan troglodytes): A cross-sectional and longitudinal assessment. Developmental Neuropsychology, 14(4), 519–533.
Abstract: Cross?sectional and longitudinal assessment of lymphocyte count and behavioral laterality was examined in a sample of captive chimpanzees (Pan troglodytes) to assess the validity of the Geschwind?Behan?Galaburda (GBG) theory of cerebral lateralization. For the cross?sectional analysis, chimpanzees classified as right?handed for feeding exhibited lower lymphocyte counts than chimpanzees classified as either ambiguously handed or left?handed. Longitudinal analysis indicated that some measures of laterality within the first 3 months of life predicted (a) direction of hand preference at 2 to 5 years of age and (b) lymphocyte counts for the first 3 years of life. The association between lymphocyte count and behavioral laterality was more evident in males than females. Taken together, the results support some aspects of the GBG theory.
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Verheyen, K., Price, J., Lanyon, L., & Wood, J. (2006). Exercise distance and speed affect the risk of fracture in racehorses. Bone, 39(6), 1322–1330.
Abstract: In order to gain insight into those training regimens that can minimise the risk of fracture in athletic populations, we conducted a large epidemiological study in racehorses. Thoroughbred racehorses provide a suitable model for studying fracture development and exercise-related risk factors in physically active populations. They represent a homogeneous population, undertaking intensive exercise programmes that are sufficiently heterogeneous to determine those factors that influence injury risk. Daily exercise information was recorded for a cohort of 1178 thoroughbreds that were monitored for up to 2 years. A total of 148 exercise-induced fractures occurred in the study population. Results from a nested case-control study showed a strong interactive effect of exercise distances at different speeds on fracture risk. Horses that exceeded 44 km at canter (< or =14 m/s) and 6 km at gallop (>14 m/s) in a 30-day period were at particularly increased risk of fracture. These distances equate to ca. 7700 bone loading cycles at canter and 880 loading cycles at gallop. Fifty-six fractures occurred in the subset of study horses that were followed since entering training as yearlings, when skeletally immature (n = 335). Cohort analysis of this data set showed that, in previously untrained bones, accumulation of canter exercise increased the risk of fracture (P < or = 0.01), whereas accumulation of high-speed gallop exercise had a protective effect (P < 0.01). However, increasing distances at canter and gallop in short time periods (up to one month) were associated with an increasing fracture risk. All training exercise involves a balance between the risk of fracture inherent in exposure to loading and the beneficial effect that loading has by stimulating bone cells to produce a more robust architecture. Results from our study provide important epidemiological evidence of the effects of physical exercise on bone adaptation and injury risk and can be used to inform the design of safer exercise regimens in physically active populations.
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Houpt, K. A., Northrup, N., Wheatley, T., & Houpt, T. R. (1991). Thirst and salt appetite in horses treated with furosemide. J Appl Physiol, 71(6), 2380–2386.
Abstract: When a preliminary experiment in sodium-replete ponies revealed an increase, but not a significant increase, in salt consumption after furosemide treatment, the experiment was repeated using sodium-deficient horses in which aldosterone levels might be expected to be elevated to test the hypothesis that a background of aldosterone is necessary for salt appetite. Ten Standardbred mares were injected intravenously with furosemide or an equivalent volume of 0.9% sodium chloride as a control to test the effect of furosemide on their salt appetite and blood constituents. Sodium intake and sodium loss in urine, as well as water intake and urine output, were measured and compared to determine accuracy of compensation for natriuresis and diuresis. Plasma protein and packed cell volume showed significant increases in response to furosemide treatment (F = 29.31, P less than 0.001 and F = 11.20, P less than 0.001, respectively). There were no significant changes in plasma sodium concentration or osmolality in response to the treatment (P greater than 0.05). The furosemide-treated horses consumed 126 +/- 14.8 g salt, significantly more than when they were given the control injection (94.5 +/- 9.8 g; t = 2.22, P = 0.05). In response to furosemide, horses lost 962 +/- 79.7 and consumed 2,170 +/- 5 meq sodium; however, compared with control, they lost 955 meq more sodium and ingested only 570 meq more sodium, so they were undercompensating for natriuresis. The furosemide-treated horses drank 9.6 +/- 0.8 kg of water, significantly more than when they received the control injection (6.4 +/- 0.8 kg; t = 6.9, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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Forster, H. V., Pan, L. G., Bisgard, G. E., Flynn, C., & Hoffer, R. E. (1985). Changes in breathing when switching from nares to tracheostomy breathing in awake ponies. J Appl Physiol, 59(4), 1214–1221.
Abstract: We assessed the consequences of respiratory unloading associated with tracheostomy breathing (TBr). Three normal and three carotid body-denervated (CBD) ponies were prepared with chronic tracheostomies that at rest reduced physiological dead space (VD) from 483 +/- 60 to 255 +/- 30 ml and lung resistance from 1.5 +/- 0.14 to 0.5 +/- 0.07 cmH2O . l-1 . s. At rest and during steady-state mild-to-heavy exercise arterial PCO2 (PaCO2) was approximately 1 Torr higher during nares breathing (NBr) than during TBr. Pulmonary ventilation and tidal volume (VT) were greater and alveolar ventilation was less during NBr than TBr. Breathing frequency (f) did not differ between NBr and TBr at rest, but f during exercise was greater during TBr than during NBr. These responses did not differ between normal and CBD ponies. We also assessed the consequences of increasing external VD (300 ml) and resistance (R, 0.3 cmH2O . l-1 . s) by breathing through a tube. At rest and during mild exercise tube breathing caused PaCO2 to transiently increase 2-3 Torr, but 3-5 min later PaCO2 usually was within 1 Torr of control. Tube breathing did not cause f to change. When external R was increased 1 cmH2O . l-1 . s by breathing through a conventional air collection system, f did not change at rest, but during exercise f was lower than during unencumbered breathing. These responses did not differ between normal, CBD, and hilar nerve-denervated ponies, and they did not differ when external VD or R were added at either the nares or tracheostomy.(ABSTRACT TRUNCATED AT 250 WORDS)
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McCutcheon, L. J., & Geor, R. J. (2000). Influence of training on sweating responses during submaximal exercise in horses. J Appl Physiol, 89(6), 2463–2471.
Abstract: Sweating responses were examined in five horses during a standardized exercise test (SET) in hot conditions (32-34 degrees C, 45-55% relative humidity) during 8 wk of exercise training (5 days/wk) in moderate conditions (19-21 degrees C, 45-55% relative humidity). SETs consisting of 7 km at 50% maximal O(2) consumption, determined 1 wk before training day (TD) 0, were completed on a treadmill set at a 6 degrees incline on TD0, 14, 28, 42, and 56. Mean maximal O(2) consumption, measured 2 days before each SET, increased 19% [TD0 to 42: 135 +/- 5 (SE) to 161 +/- 4 ml. kg(-1). min(-1)]. Peak sweating rate (SR) during exercise increased on TD14, 28, 42, and 56 compared with TD0, whereas SRs and sweat losses in recovery decreased by TD28. By TD56, end-exercise rectal and pulmonary artery temperature decreased by 0.9 +/- 0.1 and 1.2 +/- 0.1 degrees C, respectively, and mean change in body mass during the SET decreased by 23% (TD0: 10.1 +/- 0.9; TD56: 7.7 +/- 0.3 kg). Sweat Na(+) concentration during exercise decreased, whereas sweat K(+) concentration increased, and values for Cl(-) concentration in sweat were unchanged. Moderate-intensity training in cool conditions resulted in a 1.6-fold increase in sweating sensitivity evident by 4 wk and a 0.7 +/- 0.1 degrees C decrease in sweating threshold after 8 wk during exercise in hot, dry conditions. Altered sweating responses contributed to improved heat dissipation during exercise and a lower end-exercise core temperature. Despite higher SRs for a given core temperature during exercise, decreases in recovery SRs result in an overall reduction in sweat fluid losses but no change in total sweat ion losses after training.
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Harkins, J. D., Kamerling, S. G., & Church, G. (1992). Effect of competition on performance of thoroughbred racehorses. J Appl Physiol, 72(3), 836–841.
Abstract: The effect of competition and the influence of age and sex on performance were examined in a study of 18 Thoroughbred racehorses. The horses performed two solo and two competitive runs at 1,200 and 1,600 m for a total of eight runs. No group ran faster during competition, which may have been a reflection of the quality of horses used for this study and their susceptibility to stress-induced impairment of performance. Males showed no significant difference between competitive and solo run times, whereas females were consistently slower during competition. Males ran significantly faster than females in all runs. There was no difference in run times due to age, which may have been due to the high mean age (5.9 yr) of the group. The slower competitive run times may have occurred because of an earlier onset of fatigue when compared with solo runs. Plasma lactate was significantly greater for the 1,200-m competitive than for the solo runs.
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Clayton, H. M. (1993). Development of conditioning programs for dressage horses based on time-motion analysis of competitions. J Appl Physiol, 74(5), 2325–2329.
Abstract: The time-motion characteristics of Canadian basic- and medium-level dressage competitions are described, and the results are applied in formulating sport-specific conditioning programs. One competition was analyzed at the six levels from basic 1 to medium 3. Each test was divided into a series of sequences based on the type and speed of activity. The durations of the sequences were measured from videotapes. The basic-level tests had fewer sequences, and they were shorter in distance and duration than the medium tests (P < 0.10), but the average speed did not differ between the two levels. It is recommended that horses competing at the basic levels be conditioned using 5-min exercise periods, with short (10-s) bursts of lengthened trot and canter included at basic 2 and above. In preparation for medium-level competitions, the duration of the work periods increases to 7 min, 10- to 12-s bursts of medium or extended trot and canter are included, and transitions are performed frequently to simulate the energy expenditure in overcoming inertia.
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