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Biomedical subjects

J P Lavoie

Publications and source records attributed to J P Lavoie.

At least 19 recordsLinked to original sources
PubMed2006

Precision branching ratio measurement for the superallowed beta+ emitter 62Ga and isospin-symmetry-breaking corrections in A>or=62 nuclei.

A high-precision branching ratio measurement for the superallowed beta+ decay of 62Ga was performed at the Isotope Separator and Accelerator radioactive ion beam facility. Nineteen gamma rays emitted following beta+ decay of 62Ga were identified, establishing the dominant superallowed branching ratio to be (99.861+/-0.011)%. Combined with recent half-life and Q-value measurements, this branching ratio yields a superallowed ft value of 3075.6+/-1.4 s for 62Ga decay. These results demonstrate the feasibility of high-precision superallowed branching ratio measurements in the A>or=62 mass region and provide the first stringent tests of the large isospin-symmetry-breaking effects predicted for these decays.

Journal Article↗
PubMed2006

Theophylline does not potentiate the effects of a low dose of dexamethasone in horses with recurrent airway obstruction.

REASONS FOR PERFORMING STUDY: Theophylline has been shown to have corticosteroid-sparing effects for the treatment of human asthma. A similar effect, if present in horses, would allow diminishing the dose of corticosteroids administered to equine patients with inflammatory airway diseases. OBJECTIVES: To evaluate whether theophylline potentiates the effects of a low dose of dexamethasone when treating horses with recurrent airway obstruction (RAO). HYPOTHESIS: Theophylline has steroid-sparing effects in horses with RAO. METHODS: Ten mature mixed breed horses in clinical exacerbation of RAO were studied. Using an incomplete crossover design and 3 experimental periods of 7 days duration, horses were distributed randomly in 5 treatment groups; and administered dexamethasone s.i.d., at either 0.05 mg/kg bwt i.v. or per os, or 0.02 mg/kg bwt alone or combined with theophylline at 5 mg/kg bwt per os b.i.d. A fifth group was treated with theophylline alone at the above dosage. Lung function was evaluated prior to drug administration and then 3 and 7 days later. RESULTS: Oral administration of dexamethasone alone or combined with theophylline failed to improve lung function significantly in RAO affected horses. Theophylline alone also failed to improve lung function in all treated horses. Conversely, dexamethasone administration at 0.05 mg/kg bwt i.v. resulted in a significant improvement in lung function starting on Day 3. CONCLUSIONS AND POTENTIAL RELEVANCE: Oral theophylline for 7 days did not improve the effects of a low dose of dexamethasone for the treatment of horses with RAO.

Administration, Oral↗
PubMed2005

Understanding the outcomes of a psycho-educational group intervention for caregivers of persons with dementia living at home: a process evaluation.

This qualitative process evaluation study aimed to identify the primary processes of a psycho-educational group for caregivers of persons with dementia, in order to better understand intervention outcomes. Semi-structured interviews were conducted with 30 participants recruited from the experimental group of a randomised controlled trial. At pre-test, participants reported their expectations of the group. At post-test, they described their group experience, the most/least helpful aspects of the intervention, their most useful learning and their responses during a recent episode of disturbing behaviour by their relative. Results showed that the group delivered both educational and support processes. Support processes complemented educational processes. Participants learned coping strategies, with reframing playing a more important role than problem-solving or seeking social support. Daughters benefited more than spouses from educational processes. This study of group processes contributes to our understanding of the reported reduction in frequency of disturbing behaviours and of the change in caregivers' behaviours.

Caregivers↗
PubMed2004

Respiratory and metabolic effects of massive administration of isotonic saline solution in heaves-affected and control horses.

REASONS FOR PERFORMING STUDY: It has been suggested that rapid administration of isotonic saline solution relieves airway obstruction in heaves-affected horses, but the efficacy and tolerability of this treatment is poorly documented. OBJECTIVES: To determine the respiratory and metabolic effects of a rapid administration of isotonic saline solution in control horses and those with heaves. METHODS: Thirty litres isotonic saline solution were administered i.v. to 5 control (Group C) and 9 heaves-affected horses (Group H). Pulmonary function testing and arterial blood gas analysis were performed prior to saline infusion, at 90 and 180 mins after starting the infusion, and 1, 3, 6 and 10 days later. PCV, plasma total solids, plasma electrolytes (Na+, Cl- and K+) and venous blood gas analysis were performed prior, during and after saline infusion. RESULTS: Rapid saline administration was shown to have no beneficial effects on lung function during infusion in Group H. On the contrary, they had significantly increased pulmonary resistance (RL) at 180 mins following the initiation of saline administration compared to baseline. In Group C, saline administration resulted in a significant increase in RL at 180 mins and a significant decrease in PaO2 at 90 mins. These results suggest a transient decrement in lung function caused by rapid saline administration. Group H had a metabolic alkalosis with hypochloraemia at baseline compared to control horses. This resolved following i.v. saline administration and returned to baseline within 6 h after treatment had been discontinued. CONCLUSION: The administration of saline to Group H did not improve airway function significantly, but resulted in mild and transient side effects. POTENTIAL RELEVANCE: Rapid administration of isotonic saline alone is not an effective therapy for heaves in horses.

Acid-Base Equilibrium↗
PubMed2003

Comparison of efficacy and tolerability of isoflupredone and dexamethasone in the treatment of horses affected with recurrent airway obstruction ('heaves').

REASONS FOR PERFORMING STUDY: Corticosteroids are currently the most effective drugs for the control of 'heaves' in horses. However, there is limited information concerning the comparative efficacy and tolerability of the various corticosteroids when used for treatment. OBJECTIVES: To compare the therapeutic and side effects of isoflupredone acetate to those of dexamethasone. METHODS: A parallel design to compare the effects of 2 corticosteroids by evaluating lung function, serum cortisol and electrolyte concentrations, response to ACTH stimulation and haematology sequentially during a 14 day control period (no treatment), followed by 14 day treatment with either isoflupredone acetate (0.03 mg/kg i.m. s.i.d., n = 6) or dexamethasone (0.04 mg/kg i.v. s.i.d., n = 6) and 7 days of wash-out. RESULTS: Both drugs were well tolerated clinically and resulted in a significant improvement in lung function that started on Day 3 and lasted for the treatment and wash-out periods. Blood cortisol levels were significantly decreased during the treatment period in both groups of horses, but a normal response to ACTH stimulation was preserved. Serum electrolytes concentration of horses receiving dexamethasone was not affected by the treatment, but horses treated with isoflupredone demonstrated a significant decrease in serum potassium level. Both treatments induced stress changes in haematology. CONCLUSIONS AND POTENTIAL RELEVANCE: Isoflupredone is as effective as dexamethasone in the treatment of 'heaves'-affected horses but associated with hypokalaemia. Even if clinical signs of hypokalaemia were not observed, this is a side effect that deserves further investigation.

Airway Obstruction↗
PubMed2001

Neutrophilic airway inflammation in horses with heaves is characterized by a Th2-type cytokine profile.

Heaves in horses shares many similarities with human asthma, including lower airway inflammation, reversible airway obstruction, and bronchial hyperresponsiveness. Extrinsic asthma is an allergic response to environmental allergens and a similar immunologic mechanism may be implicated in heaves. It is now recognized that a Th2 subset of CD4+ lymphocytes is associated with allergic diseases such as atopic asthma. The purpose of this study was to determine whether airway inflammation in heaves is associated with a pattern of expression of cytokine suggestive of a Th2 type response. The expression of mRNA, encoding interleukin (IL)-4, IL-5, and interferon gamma (IFN-gamma) was measured in bronchoalveolar cells from seven horses with heaves and five control horses, using in situ hybridization and radiolabeled equine-specific cRNA probes coding for these cytokines. Bronchoalveolar cells of horses with heaves had an increased expression of IL-4 (p = 0.01) and IL-5 (p = 0.02) mRNA and a decreased expression of INF-gamma (p = 0.01) compared with control horses. Here we show that inflammatory cells in lungs from horses with heaves display a Th2-type cytokine profile that is consistent with the hypothesis that heaves is an allergic condition with similarity to human asthma.

Animals↗
PubMed2001

[Comparison of direct smear observations and bacteriologic culture results carried out on equine tracheal secretions].

The aim of the study was to assess the relation between the direct smear observations and bacteriological results carried out on equine tracheal secretions. A total of 304 cases comprising both the direct smear (Gram stain) and the bacteriological culture, over a period of 8 years, were submitted to this retrospective study. Most of the specimens (78%) were obtained using tracheal washings while the rest (22%) originated from tracheal brushings. A total of 96 specimens (32%) were negative for both direct smear and culture. The positive predictive value of direct smears appeared high (81-96%) while the negative predictive value was lower (48-79%). Sensitivity of direct smear was considered as low and varied from 24 to 46% for tracheal brushings and from 41 to 46% for tracheal washings. Specificity of direct smear was high for both types of specimens. Results of this study indicate that the use of Gram-stained smear examination, carried out on tracheal secretions, is a technique which is specific but not very sensitive for the prediction of bacteriological culture results. Moreover, the use of tracheal washing, more than tracheal brushing, seems to increase the sensitivity of the test.

Animals↗
PubMed2000

Effects of pulmonary abscesses on racing performance of horses treated at referral veterinary medical teaching hospitals: 45 cases (1985-1997).

OBJECTIVE: To determine whether results of physical or radiographic examination or biochemical analyses in adult racehorses with primary lung abscesses were associated with ability to race following treatment. DESIGN: Multiple-center retrospective study. ANIMALS: 25 Standardbreds and 20 Thoroughbreds. PROCEDURE: Medical records of horses with a primary lung abscess that were admitted to any of 4 veterinary teaching hospitals were reviewed. Results of physical examination, laboratory testing, and thoracic radiography were reviewed. Racing performance after treatment was compared with performance before illness and with performance of the general population of racehorses of similar age, sex, and breed. RESULTS: 23 of 25 Standardbreds and 13 of 20 Thoroughbreds raced after diagnosis and treatment of a lung abscess. Most horses had a solitary abscess in the dorsal to caudodorsal lung fields. Results of initial physical examination, biochemical analyses, and culture and identification of the microbial isolate were not associated with whether a horse returned to racing. For horses that had raced prior to the illness, race performance after treatment of the lung abscess was not significantly different from performance before the illness. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of racing performance in those horses that resumed racing after treatment, long-term residual lung damage did not develop in horses with primary lung abscesses that were treated appropriately. It is not known whether horses that recovered would be more likely to bleed from the site of a prior infection when resuming strenuous exercise and whether lung abscesses contributed to a failure to resume racing.

Animals↗
PubMed2000

Equine proliferative enteropathy: a cause of weight loss, colic, diarrhoea and hypoproteinaemia in foals on three breeding farms in Canada.

Proliferative enteropathy (PE) is a transmissible enteric disease caused by Lawsonia intracellularis. An outbreak of equine PE was diagnosed in foals from 3 breeding farms. Most foals had been weaned prior to the appearance of clinical signs, which included depression, rapid and marked weight loss, subcutaneous oedema, diarrhoea and colic. Poor body condition with a rough haircoat and a potbellied appearance were common findings in affected foals. Respiratory tract infection, dermatitis and intestinal parasitism were also found in some foals. Haematological and plasma biochemical abnormalities included hypoproteinaemia, transient leucocytosis, anaemia and increased serum creatinine kinase concentration. Postmortem diagnosis of PE was confirmed on 4 foals based on the presence of characteristic intracellular bacteria within the apical cytoplasm of proliferating crypt epithelial cells of the intestinal mucosa, using silver stains, and by results of PCR analysis and immunohistochemistry. Antemortem diagnosis of equine PE was based on the clinical signs, hypoproteinaemia and the exclusion of common enteric infections. Faecal PCR analysis was positive for the presence of L. intracellularis in 6 of 18 foals tested while the serum of all 7 foals with PE serologically evaluated had antibodies against L. intracellularis. Most foals were treated with erythromycin estolate alone or combined with rifampin for a minimum of 21 days. Additional symptomatic treatments were administered when indicated. All but one foal treated with erythromycin survived the infection. This study indicates that equine PE should be included in the differential diagnosis of outbreaks of rapid weight loss, diarrhoea, colic and hypoproteinaemia in weanling foals.

Animal Husbandry↗
PubMed1999

Monthly, daily, and circadian variations of measurements of pulmonary mechanics in horses with chronic obstructive pulmonary disease.

OBJECTIVES: To determine temporal variations of pulmonary function in horses without respiratory tract disease (controls) and horses with chronic obstructive pulmonary disease (COPD) and determine whether reversibility of airway obstruction after environmental control can be predicted by response to atropine administration. ANIMALS: 7 COPD-affected and 5 control horses. PROCEDURES: Pulmonary function testing was performed monthly during 3 consecutive months, daily for 5 consecutive days, and at 6-hour intervals for 24 hours before and after administration of atropine (0.02 mg/kg of body weight, i.v.) and after 5 consecutive months at pasture. Respiratory rate, tidal volume (VT), minute ventilation (VE), maximal change in transpulmonary pressure (deltaP(L)), pulmonary resistance (R(L)), and pulmonary elastance (E(L)) were calculated. RESULTS: COPD-affected horses had a significantly higher expiratory to inspiratory time ratio (T(E)/T(I)) and deltaP(L), E(L), and R(L) than horses without respiratory tract diseases during all periods and higher V(E) during monthly and daily evaluations. Daily variation in VT and monthly and circadian variation in E(L) were significant in COPD-affected horses. In control horses, significant changes were apparent only in T(E)/T(I) during daily recordings. In COPD-affected horses, reduction in deltaP(L), R(L), and E(L) was significant after atropine administration and after maintenance on pasture. CONCLUSIONS AND CLINICAL RELEVANCE: Despite variations in measurements of respiratory mechanics in both groups of horses, values remained significantly different between groups over time. Despite individual variation, measurements were repeatable during short and long periods. Response to administration of atropine to COPD-affected horses underestimated improvement in respiratory tract function that resulted from maintenance on pasture.

Animals↗
PubMed1999

[Control measures for contagious enteric diseases in a veterinary teaching hospital].

Instructions and control measures related to enteric contagious diseases at the Veterinary Medical Teaching Hospital (VMTH) of the Faculty of Veterinary Medicine of the University of Montreal are presented. These control measures, which have given satisfactory results within the past decade, are exemplified by a salmonellosis outbreak that occurred in spring 1996 in the large animal clinic of the VMTH. Emphasis was put on the importance of antigenic and/or genetic characterizations of Salmonella isolates, in order to detect an eventual source of contamination, but also to determine the incidence of nosocomial infections among hospitalized animals.

Animals↗
PubMed1998

Associations between physical examination, laboratory, and radiographic findings and outcome and subsequent racing performance of foals with Rhodococcus equi infection: 115 cases (1984-1992).

OBJECTIVE: To determine whether physical examination, laboratory, or radiographic abnormalities in foals with Rhodococcus equi infection were associated with survival, ability to race at least once after recovery, or, for foals that survived and went on to race, subsequent racing performance. DESIGN: Retrospective study. ANIMALS: 49 Thoroughbreds and 66 Standardbreds admitted to 1 of 6 veterinary teaching hospitals between 1984 and 1992 in which R equi infection was positively diagnosed. PROCEDURE: Results of physical examination, laboratory testing, and thoracic radiography were reviewed. Indices of racing performance were obtained for foals that recovered and eventually raced and compared with values for the US racing population. RESULTS: 83 (72%) foals survived. Foals that did not survive were more likely to have extreme tachycardia (heart rate > 100 beats/min), be in respiratory distress, and have severe radiographic abnormalities on thoracic radiographs at the time of initial examination than were foals that survived. Clinicopathologic abnormalities were not associated with whether foals did or did not survive. Forty-five of the 83 surviving foals (54%) eventually raced at least once, but none of the factors examined was associated with whether foals went on to race. Racing performance of foals that raced as adults was not significantly different from that of the US racing population. CLINICAL IMPLICATIONS: R equi infection in foals is associated with a decreased chance of racing as an adult; however, foals that eventually go on to race perform comparably to the US racing population.

Actinomycetales Infections↗
PubMed1998

Use of laparoscopic equipment to divide abdominal adhesions in a filly.

Exploratory laparoscopy of the right dorsal portion of the abdominal cavity was performed on a Standardbred filly because of signs of mild abdominal pain of 7 days' duration. On the basis of clinical examination, diagnosis was suppurative peritonitis, abdominal adhesions in the area of the right ovary, and right displacement and impaction of the pelvic flexure of the ascending colon. During laparoscopy, an abdominal adhesion between the right uterine horn, the cecum, and the pelvic flexure was identified. The abdominal adhesions were either stretched with laparoscopic forceps used as a probe or dissected bluntly with the tips of a pair of 10-mm laparoscopic Kelly forceps. Antibiotics were administered for 21 days after surgery. The horse fully recovered and raced 11 months after the surgery.

Abdominal Pain↗
PubMed1998

Effects of inhaled beclomethasone dipropionate on respiratory function in horses with chronic obstructive pulmonary disease (COPD).

The effects of beclomethasone dipropionate on pulmonary function and arterial blood gas values were investigated in horses with chronic obstructive pulmonary disease (COPD). Six mature mares, diagnosed as having COPD based on clinical signs, cytological examination of bronchoalveolar lavage and pulmonary function testing, were used. Beclomethasone dipropionate (3750 microg) was administered b.i.d. for a 2 week period with a metered dose inhaler using a mask. Pulmonary function tests and arterial blood gas analyses were performed at weekly intervals, starting before beclomethasone administration and for 4 weeks thereafter. Upper airway endoscopy and nasopharyngeal fungal cultures were performed before and after treatment. Maximal variations in transpulmonary pressure (deltaPL) were elevated in all horses at baseline. Beclomethasone administration resulted in a significant decrease in deltaPL in 5 horses, and deltaPL fell to within the normal range in 4 horses. Two weeks after the end of treatment, deltaPL was at or above baseline values in all horses. Total pulmonary resistance and elastance decreased significantly during treatment and returned to or above baseline values after the administration of beclomethasone was discontinued. At baseline, PaO2 range was 53-90 mmHg. In 4 horses with pronounced laboured breathing, PaO2 increased with treatment. One horse became reluctant to inhale the beclomethasone after one week, and only a transient improvement in respiratory function was noted in this animal. One horse developed a mild lower airway infection 24 h after the beginning of treatment, but no other possible side effects were noticed. Pharyngeal fungal cultures were negative before and after treatment. It can be concluded from the results of this study that inhaled beclomethasone dipropionate causes a marked improvement of respiratory function in horses with COPD.

Administration, Inhalation↗
PubMed1998

Effect of time-varying load on degree of bronchoconstriction in the dog.

It is well established that the degree of airway smooth muscle shortening produced by a given dose of bronchial agonist is greatly affected by lung volume. The airways are tethered by parenchymal attachments, the tension of which increases progressively with lung volume, thereby presenting a commensurately increasing hindrance to smooth muscle contraction. Earlier studies (P. F. Dillon, M. O. Aksoy, S. P. Driska, and R. A. Murphy. Science 211: 495-497, 1981) presented evidence that smooth muscle contraction initially involves rapidly cycling cross bridges, which then change to noncycling (latch) bridges. They also suggested that most of the muscle shortening occurs during the early rapid cross-bridge phase. This implies that smooth muscle subject to a given load early in contraction should shorten less than when it is subject to the same load later on. An in vitro study (W. Li and N. L. Stephens. Can. J. Physiol. Pharmacol. 72: 1458-1463, 1994) obtained support for this notion. To test this hypothesis in vivo, we measured the changes in lung impedance at 1 and 6 Hz produced in dogs by a bolus intravenous injection of methacholine when lung volume was increased for 10 s at different times after injection. We found that the changes in mechanics were greatly inhibited, whereas lung volume was elevated. However, when lung volume was returned to its initial level, the lung mechanics continued to change at a rate unaffected by the preceding volume change. We conclude that temporary mechanical inhibition of airway smooth muscle shortening in the normal dog in vivo merely delays an otherwise normal course of contraction.

Animals↗
PubMed1998

[Prevalence of infections caused by Salmonella spp. in cattle and horses at the Veterinary Teaching Hospital of the Faculty of Veterinary Medicine of the University of Montreal].

Bacteriologic detection of Salmonella spp. from feces of animals admitted to Veterinary Teaching Hospital of the Faculty of Veterinary Medicine, University of Montréal, in Saint-Hyacinthe was carried out during a 1-year period to estimate the prevalence of bovine and equine salmonellosis. Prevalence at the time of hospitalization was quite low: 1.4% in cattle and 1.7% in horses. Incidence was 15.1 cases/100 animal/year in cattle and 38.7 cases/100 animal/year in horses. Serotype typhimurium was the most prevalent in both species. In cattle, cases were evenly distributed over the year. In horses, a recrudescence of cases and a obviousness of transmission were apparent in April 1996.

Animals↗