Nephroblastoma in an adult sheep.
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Animals↗
Biomedical subjects
S A Headley
Publications and source records attributed to S A Headley.
Phylogenetic analysis of Anaplasma marginale strains from Paraná State, Brazil, using the msp1alpha and msp4 genes.
Anaplasma marginale is an obligate intraerythrocytic rickettsial pathogen (order, Rickettsiales: family, Anaplasmataceae) that causes bovine anaplasmosis. This disease is widely distributed in tropical and sub-tropical regions of the world and causes important economic losses to cattle production. Major surface protein (MSP)1a (msp1alpha gene) is one of the six MSPs identified on A. marginale from cattle, whose sequence and size vary according to the number of tandem 28- to 29-amino acid repeats. This study characterized the msp1alpha and msp4 genes obtained from three distinct Brazilian herds from the State of Paraná. Three strains of the msp1alpha and one strain of the msp4 gene were sequenced. The strains evaluated revealed PCR products of different size, representing three, five and six internal repeats. Sequence analyses confirmed the number of tandem sequence copies and revealed a high degree of sequence identity with strains from other Brazilian States, as well as strains from the USA, Europe and Israel. The msp1alpha DNA and amino acid sequences from A. marginale and DNA sequences of msp4 strains did not reveal distinct phylogeographical segregation. However, the amino acid sequences of msp4 demonstrated definite phylogeographical relationship. These results suggest that the amino acid sequences of msp4 should be used for phylogenetic identification of A. marginale strains and may be an important tool for the epidemiology and control of anaplasmosis. Additionally, the close similarity of the Paraná strains of A. marginale with strains from USA, Europe and Asia may reflect the introduction of these genes during the development of the Brazilian bovine herd.
Amino Acid Sequence↗
Intrathoracic haemangiosarcoma in an ostrich (Struthio camelus).
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Animals↗
Renin and hemodynamic responses to exercise in borderline hypertensives.
OBJECTIVE: In this study, we examined the relationship between baseline plasma renin (REN) and hemodynamic variables during recovery from aerobic exercise in 10 Caucasian (C) and 10 African-American (AA) borderline hypertensive females. METHODS: Subjects attended three preliminary sessions and an experimental session in which treadmill walking was performed for 40 minutes at a moderate intensity. During this session, blood was drawn at baseline prior to exercise and immediately following. Blood pressure and other hemodynamic variables were recorded at rest before exercise and for 2 hours afterwards. The average difference from baseline during the two hour recovery period was calculated for each variable and used as the dependent variable in a multiple regression analysis. RESULTS: For mean arterial pressure and cardiac output, the regression slopes did not differ between AA and C. However, during recovery, the average difference from baseline for systemic vascular resistance (SVR) increased in AA but decreased in C. CONCLUSION: In conclusion, REN had a significant effect on SVR but no effect on the other hemodynamic variables during recovery from aerobic exercise. It appears as if the peripheral vasculature in AA may be more sensitive than in C to the vasoconstrictive effects of the renin angiotensin system.
Adult↗
Cardiovascular responses to beta-blockade and 5 degrees C cold air stress.
To determine the cardiovascular responses to beta-blockade and cold air stress, six males were randomly exposed at rest to three drug conditions (placebo, nonselective beta-blockade (propranolol), and selective beta-blockade (atenolol)) in each of two environments (5 and 25 degrees C) for 1 h. Cardiac output was lower on beta-blockade than on the placebo in both the 25 and 5 degrees C environments. Cardiac output on propranolol (4.2 +/- 0.3 L.min-1) at 5 degrees C was lower than on atenolol (4.7 +/- 0.4 L.min-1, p < 0.05). Mean arterial pressure was greater (p < 0.05) at 5 than 25 degrees C for each drug condition. There was no drug effect on total peripheral resistance at 25 degrees C. At 5 degrees C, total peripheral resistance on both beta-blockers (propranolol 1942.7 +/- 169.9 dyn.s.cm-5 (1 dyn = 10 microN); atenolol 1706.7 +/- 160.0 dyn.s.cm-5) was higher (p < 0.05) than on the placebo (1485.3 +/- 111.8 dyn.s.cm-5). Total peripheral resistance was also higher on propranolol than atenolol (p < 0.05). In conclusion, cold air stress interacts with beta-blockade to elevate total peripheral resistance by decreasing cardiac output while having little effect on mean arterial pressure. These effects are greater on nonselective than on selective blockade.
Adult↗
Periodic carbohydrate replacement during 50 min of high-intensity cycling improves subsequent sprint performance.
The purpose of this study was to investigate the effect of 7% carbohydrate-electrolyte (CE) drink on sprint capacity immediately following 50 min of high-intensity cycling. After an overnight 12-hr fast, 8 trained male cyclists performed two 50-min simulated time trials on a Monark stationary cycle ergometer. Subjects consumed either the CE or a flavored water placebo (PL) at 10, 20, 30, and 40 min during the time trial. At the conclusion of each 50-min time trial, subjects immediately performed a Wingate Anaerobic Power Test. Peak power, mean power, and minimum power were significantly higher for the CE trials, whereas mean RPE was significantly lower. Mean heart rate and fatigue index were not different between trials. These results suggest that sprint performance following a high-intensity simulated time trial of only 50 min can be improved with periodic consumption of CE during the ride, particularly following an overnight fast, when liver glycogen is likely to be low. These findings have implications for competitive cycling, where sprint capacity at the conclusion of a race is an important determinant of success.
Adult↗
Glial fibrillary acidic protein (GFAP)-immunoreactive astrocytes in dogs infected with canine distemper virus.
An experiment based on astrocyte immunoreactivity to glial fibrillary acidic protein (GFAP) was designed to determine whether the astrocyte response in canine distemper encephalitis (CDE) was associated with the age of the animal, type of lesion and the cerebellar region affected. Four histopathological types of CDE lesion were examined, namely acute (11 dogs), acute with necrosis (four dogs), subacute (22 dogs) and chronic (six dogs). The animals were divided into three age groups, namely, 0-2 years (27 dogs), 2.1-4 years (12 dogs), and 4.1-12 years (four dogs). Three different cerebellar regions were evaluated. Cerebellar sections from three healthy dogs were used for control purposes. The highest number of astrocytes occurred in the cerebellar white matter and in dogs with acute distemper encephalopathy. In animals with subacute distemper encephalitis, the numbers of astrocytes appeared to increase with age, but the opposite effect occurred in dogs with acute or chronic encephalitis; age appeared not to influence the astrocyte numbers in dogs suffering from acute encephalitis with necrosis.
Acute Disease↗
Hemodynamic responses associated with post-exercise hypotension in normotensive black males.
The purpose of this study was to characterize the hemodynamic responses during recovery from moderate intensity exercise in young black normotensive males. Nineteen normotensive men (age 25.0 +/- 1.0 yrs, VO2peak 48.8 +/- 1.5 ml.kg-1.min-1) walked continuously on a treadmill for 40 minutes at 50-60% heart rate reserve. Following exercise, blood pressure (by auscultation) and hemodynamic variables (impedance cardiography) were monitored for two hours in a quiet room with subjects in a seated posture. During the initial 40 minutes of recovery, cardiac output, (Q) was significantly greater than the pre-exercise baseline (p < 0.05). This was mediated by heart rate, which was elevated above the pre-exercise baseline for 75 minutes. Mean systolic blood pressure (SBP) was reduced by at least 7 mm Hg from 30 minutes to 2 hours post-exercise, compared to the pre-exercise baseline, (mean = 112 +/- 1.6) (p < 0.05). Total peripheral resistance (TPR, dyne.s.cm-5) was depressed for 60 minutes compared to the pre-exercise baseline (BL, 959.8 +/- 40.6), p < 0.05, but was fully recovered by two hours. It was concluded that in this group of young black normotensive males, moderate intensity aerobic exercise led to a prolonged reduction in SBP through relative changes in Q and TPR. These observations have not been consistently observed by other investigators in normotensive white males under similar experimental conditions.
Adult↗