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Biomedical subjects

J A Boon

Publications and source records attributed to J A Boon.

12 recordsLinked to original sources
PubMed2000

Influence of open surgical correction on intermediate-term outcome in dogs with subvalvular aortic stenosis: 44 cases (1991-1998).

OBJECTIVE: To compare outcome and intermediate-term survival for dogs undergoing open surgical correction of subvalvular aortic stenosis (SAS) with those for dogs with SAS that did not undergo surgery. DESIGN: Retrospective study. ANIMALS: 44 dogs with congenital SAS. PROCEDURE: Maximum instantaneous systolic pressure gradients were determined by use of Doppler echocardiography. Cardiopulmonary bypass and open surgical correction of SAS (membranectomy with or without septal myectomy) was performed in 22 dogs, whereas 22 dogs did not undergo surgical correction. Cumulative survival was compared between surgical and nonsurgical groups, using Kaplan-Meier nonparametric analysis and a Mantel-Cox log-rank test. RESULTS: Initial systolic pressure gradients were not significantly different for dogs undergoing surgery (128 +/- 55 mm Hg), compared with those that did not undergo surgery (117 +/- 57 mm Hg). Systolic pressure gradients were significantly decreased after surgery in dogs that underwent surgery (54 +/- 27 mm Hg). Cumulative survival was not significantly different between dogs in the surgical and nonsurgical groups. Censoring surgery-related mortality in the analysis still did not reveal a significant difference in cumulative survival between the surgical and nonsurgical groups. CONCLUSIONS AND CLINICAL RELEVANCE: Despite reductions in the systolic pressure gradient and possible associated improvement in exercise tolerance, a palliative benefit on survival was not documented in dogs undergoing surgery for SAS.

Adrenergic beta-Antagonists↗
PubMed1998

Atrioventricular septal defects in three llamas (Lama glama).

Two half-sibling neonatal llamas (Lama glama) and one unrelated adult llama were presented with various complaints, including failure to thrive, respiratory distress, and excessive recumbency. The related camelids were born in successive years to the same dam but from unrelated sires. Thoracic auscultation revealed significant systolic and diastolic murmurs on both sides of the chest in all three llamas, and arterial blood gas evaluation revealed hypoxemia in two llamas. Echocardiographic examinations revealed large atrioventricular septal (AVS) defects in all three llamas. Two llamas were euthanized after diagnosis and the third died 4 mo later. Postmortem examination confirmed large AVS defects in all animals. There also was marked cardiomegaly in each animal. The discovery of such a cardiac anomaly in these three camelids suggests that it may be common in this species and may have a genetic basis.

Animals↗
PubMed1996

Adolescents' reported usage of selected foods in relation to their perceptions and social norms for those foods.

This paper reports a study of factors associated with the consumption of 22 diverse foods among 2082 students aged 12-15 years in Tasmania, Australia. Students provided data by completing a printed questionnaire. Multiple linear regression was used to assess how well self-reported usual (past) frequency of consumption of a food could be estimated from their perceptions of the qualities of the food (their liking for it, its healthfulness) and their descriptive social norms for the food (its usage by parents and its usage by friends). For all foods, multiple R was significant (p < 0.0001), with values ranging from 0.28-0.64 (median for the 22 foods being 0.49). Standardized regression coefficients for liking and parental usage were highly significant (p < 0.0001) for all foods. However, consistently lower coefficients were found for friends' usage (11 with p < 0.01, but only three with p < 0.0001) and healthfulness (five with p < 0.01, but only one with p < 0.0001). The absolute and relative magnitudes of the regression coefficients varied substantially between the foods. Liking was a stronger predictor than parental usage for 11 of the foods, and parental usage out-ranked liking for the remaining 11. Regression coefficients for friends' usage and healthfulness were smaller than those for liking and parental usage for all foods studied.

Adolescent↗
PubMed1994

Llama cardiology.

Auscultatory, ECG, and echocardiographic data have been presented for healthy llamas. The literature, however, contains little information on the incidence of congenital and acquired heart disease in the llama. Data compiled from the medical records at CSU-VTH and the VMDB provide an indication of the types of cardiac disease to be found in llamas in North America. A wide variety of congenital cardiac defects are found in llamas, the most prevalent defect of which is VSD. Llamas tend to do well with this defect but are unlikely to be useful pack animals. Acquired heart disease primarily involved inflammatory processes of the pericardium, endocardium, epicardium, and myocardium, and pericardial effusion without documented inflammatory disease. Although not every cardiac murmur necessitates a complete cardiac work-up, every effort should be made to compile accurate medical histories and physical findings related to the cardiac disease in llamas in order to advance our knowledge of these disorders. There also is a need to use available technologies to better define cardiac abnormalities in the llama and accurately report these findings in the literature before cardiology of llamas is fully understood.

Animals↗
PubMed1989

The fat content of suckled breast milk: a new approach to its assessment.

Using a modification of the "interrupted feed" technique (Woolridge et al., 1982, Early Hum. Dev., 6, 265-272), the authors devised an equation relating milk fat content at any point during a feed from a breast to the volume consumed since the start of the feed. Hence, an equation was obtained to estimate the mean fat content (MF) of milk consumed during a feed from the fat content of small samples of fore-milk (Fb) and hind-milk (Fe): MF = 0.57Fb + 0.43Fe The authors argue that their approach yields a closer approximation to the true value of MF than previously described estimators of MF.

Adult↗
PubMed1989

Human milk fat content: within-feed variation.

Changes in milk fat content during individual breast-feeds were studied using a modification of the interrupted feed technique (Woolridge et al. (1982): Early Human Dev., 6, 265-272). Each feed was interrupted once, for weighing the baby and obtaining a small milk sample; weighing and milk sampling were also done at the start and end of the feed from that breast. Mathematical analysis of 52 feeds from the first breast offered at a feeding episode, and 39 second-breast feeds, showed a similar pattern on both types. The fat content rose in line with (Vi/Ve)1.35 (V being the volume consumed since the feed from that breast began). However, first-breast feeds showed sharp initial and final rises in fat content. The authors propose a mechanism to explain the difference in pattern between first- and second-breast feeds.

Adult↗
PubMed1988

Real-time ultrasonography for determining pregnancy status and viable fetal numbers in ewes.

The reproductive tracts of 26 estrus synchronized, bred ewes were scanned with a portable 5.0 MHz real-time ultrasound unit within 1 to 6 d postbreeding. Intrarectal scanning was performed on alternate days until Days 28 to 30 and twice weekly until Days 50 of gestation. Transabdominal uterine scans were conducted twice weekly from Days 25 to 65 and continued weekly until parturition. A total of 24 ewes (92%) became pregnant. A nonpregnant ewe was recognized 100% of the time by both methods of ultrasonic screening. Correct identification of a gravid ewe as pregnant was 100% from Days 51 to 150 of gestation using transabdominal real-time ultrasonography. There was a significant association (P < 0.005) between the number of lambs born and the number of fetuses observed using transabdominal real-time ultrasonography after Day 25 of gestation. Accurate differentiation of fetal numbers by transabdominal scanning was 100.0% for ewes carrying one lamb and 97.3% for ewes carrying two lambs at Days 51 to 75 of gestation. Fetal attrition was documented in one ewe at Day 49 of gestation. Hydrops allantois was diagnosed in another ewe at 110 d of gestation. A total of 37 lambs were born to 23 ewes in the project flock. No congenital abnormalities were noted in any of the lambs. Transabdominal real-time ultrasonography is a safe, rapid, accurate and practical method for assessing pregnancy status, fetal number and fetal viability in sheep.

Journal Article↗
PubMed1987

Echocardiography for the diagnosis of congenital heart defects in the dog.

Echocardiography utilizing M-mode and real-time techniques is a safe, noninvasive diagnostic technique for use in veterinary cardiology. It provides a means to assess structural sizes and relationships and can be used to provide quantitative data for diagnosis of congenital heart disease. Although its availability is largely limited to veterinary colleges and specialty hospitals, the practicing veterinarian should know of its advantages and disadvantages. He or she is also encouraged to consider the use of ultrasound in the diagnosis and management of heart disease in all species of veterinary patients.

Animals↗
PubMed1987

M-mode echocardiographs of endurance horses in the recovery phase of long-distance competition.

M-mode echocardiographic structures, and cardiac function indices, PCV, and total plasma protein values were determined for 34 endurance equine athletes before (base line) and after (after race) a 161-km endurance competition and were compared. The PCV (base-line mean, 37%; after-race mean, 46%) and total plasma protein value (base-line mean, 6.9 g/dl; after-race mean, 7.5 g/dl) increased. Compared with base-line echocardiography, after-race echocardiography indicated an increase in heart rate, as determined from the simultaneous ECG recorded on the echocardiograph (base-line mean, 41 beats/min; after-race mean, 54 beats/min), and an increase in interventricular septal diastolic thickness (base-line mean, 28 mm; after-race mean, 33 mm). The septal thickening fraction (base-line mean, 59%; after-race mean, 38%), the left atrioventricular valve E to F slope (base-line mean, 224 mm/s; after-race mean, 175 mm/s), the left ventricular diastolic dimension (base-line mean, 99 mm; after-race mean, 86 mm), the fractional shortening of the left ventricle (base-line mean, 41%; after-race mean, 37%), the aortic root dimension (base-line mean, 63 mm; after-race mean, 58 mm), the caudal aortic wall excursion (base-line mean, 19 mm; after-race mean, 11 mm) and the left atrial diastolic dimension (base-line mean, 46 mm; after-race mean, 39 mm), decreased significantly (P less than 0.05). In base-line echocardiographs, late diastolic left atrioventricular valve motion was evident in 9 horses. The aberrant left atrioventricular valve motion was not evident in after-race echocardiographs. Seemingly, central vascular volume decreased in these horses during the recovery phase of severe strenuous endurance competition.

Animals↗
PubMed1983

Echocardiographic assessment of congenital aortic stenosis in dogs.

Eleven dogs with congenital aortic stenosis were studied with M-mode echocardiography. In these dogs, the aorta was increased in dimension during diastole (P less than 0.02) and systole (P less than 0.05). The left ventricular outflow tract was decreased in dimension (P less than 0.01). There was premature, early systolic closure of the aortic valve in 45% of the dogs. Concentric hypertrophy of the left ventricle was confirmed via echocardiography, as evidenced by increased dimension of the left ventricular wall (P less than 0.01) and interventricular septum (P less than 0.01).

Animals↗
PubMed1982

Applications of ultrasound to veterinary diagnostics in a veterinary teaching hospital.

Animal patients at Colorado State University's Veterinary Teaching Hospital as well as beagles at the Collaborative Radiological Health Laboratory (CRHL) have been routinely evaluated using a variety of ultrasonic procedures that are commonplace in human medicine. The results from these clinical investigations have provided diagnostic information which in many cases has not been available using other clinical testing methods. Dogs, cats, horses, and cattle have been the primary animals evaluated, but more exotic subjects such as rabbits, ferrets, goats, and armadillos have also been examined. Standard M mode echocardiographic and classic contact scanning have been used to evaluate the heart and abdominal-pelvic areas respectively. Recently, real time scanning has been added to our capabilities for evaluating animal subjects. These clinical studies, while obviously adding to veterinary diagnostics have also become an exciting new area in the veterinary teaching program. Ultrasound has shown potential in a variety of studies employing animal models, i.e., aging effects on the heart in beagles and anthracycline-induced myocardial dysfunction in rabbits.

Animal Diseases↗