Jacques Lavoie

Isolation of equine bone marrow-derived mesenchymal stem cells: a comparison between three protocols

REASON FOR PERFORMING THE STUDY There is a need to assess and standardise equine bone marrow (BM) mesenchymal stem cell (MSC) isolation protocols in order to permit valid comparisons between therapeutic trials at different sites. OBJECTIVE To compare 3 protocols of equine BM MSC isolation: adherence to a plastic culture dish (Classic) and 2 gradient density separation protocols (Percoll and Ficoll). MATERIALS AND METHODS BM aspirates were harvested from the sternum of 6 mares and MSCs isolated by all 3 protocols. The cell viability after isolation, MSC yield, number of MSCs attained after 14 days of culture and the functional characteristics (self-renewal (CFU) and multilineage differentiation capacity) were determined for all 3 protocols. RESULTS The mean +/- s.d. MSC yield from the Percoll protocol was significantly higher (6.8 +/- 3.8%) than the Classic protocol (1.3 +/- 0.7%). The numbers of MSCs recovered after 14 days culture per 10 ml BM sample were 24.0 +/- 12.1, 14.6 +/- 9.5 and 4.1 +/- 2.5 x 10(6) for the Percoll, Ficoll and Classic protocols, respectively, significantly higher for the Percoll compared with the Classic protocol. Importantly, no significant difference in cell viability or in osteogenic or chondrogenic differentiation was identified between the protocols. At Passage 0, cells retrieved with the Ficoll protocol had lower self-renewal capacity when compared with the Classic protocol but there was no significant difference between protocols at Passage 1. There were no significant differences between the 3 protocols for the global frequencies of CFUs at Passage 0 or 1. CONCLUSIONS AND CLINICAL RELEVANCE These data suggest that the Percoll gradient density separation protocol was the best in terms of MSC yield and self-renewal potential of the MSCs retrieved and that MSCs retrieved with the Ficoll protocol had the lowest self-renewal but only at passage 0. Then, the 3 protocols were equivalent. However, the Percoll protocol should be considered for equine MSC isolation to minimise culture time.

Evaluation of Bioaerosols in a Municipal Solid Waste Recycling and Composting Plant

Abstract Both the processing of solid waste and the composting of organic matter generate airborne biological contaminants. For this type of environment, some authors have proposed Threshold Limit Values (TLV) of 10,000 Colony Forming Units per cubic meter (CFU/m3) of air for total bacteria, and 1,000 CFU/m3 of air for Gram-negative bacteria. Endotoxins produced by Gram-negative bacteria can cause fever and respiratory problems. Diarrhea and gastrointestinal problems can also be caused by Gram-negative bacteria. Other researchers have found Aspergillus fumigatus, which is considered an opportunistic pathogenic fungus, in the nose and throat of people exposed to compost. The objectives of this study were to evaluate the microbiological content of indoor and outdoor air, to detect concentrations of total and Gram-negative bacteria exceeding their proposed TLV, and to suggest corrective measures based on the technical and scientific literature. Air sampling was carried out twice in one day using Andersen sam...

Penetrating wounds of the thorax in 15 horses

Clinical features, treatment and outcome of 15 horses with penetrating thoracic wounds are described. The most common cause of trauma was collision with an object (10 horses). Concurrent clinical findings included subcutaneous emphysema (12 horses), pneumothorax (12 horses), haemothorax (5 horses) and pneumomediastinum (6 horses). Axillary wounds were present in 5 horses. Foreign bodies were identified and removed from 2 horses. Wounds were sutured (6 horses) or packed (7 horses). Air was evacuated from the pleural cavities of 11 horses. Eleven horses (73%) were discharged from the hospital. All horses subjected to euthanasia had severe trauma to structures outside the thoracic cavity including perforation of the colon (2 horses), renal trauma (1 horse) and a luxated thoracolumbar vertebra (1 horse). From this study, it can be concluded that 1) the prognosis for horses with penetrating thoracic wounds, without extrathoracic injury, is favourable; 2) a thorough evaluation including the abdominal cavity should be performed and 3) horses with axillary wounds should be monitored closely for respiratory distress until the wound has completely healed.

Evaluation of bacterial contamination and control methods in soluble metalworking fluids.

In the United States, 1.2 million workers are exposed to metalworking fluids. During operations, aerosols are produced and airborne contaminants can be inhaled. Although biocides are used to control the bacterial content of metalworking fluids, they can create health-related problems, and their efficiency remains to be proved. The objectives of this project were (1) to verify whether rigorous cleaning according to a standard protocol could reduce microbial contamination and (2) whether the use of biocides with different spectra could reduce the bacterial population. Four similar machines producing similar components were evaluated; a specific treatment was applied to each machine. The machine used as a control (1) was thoroughly cleaned prior to sampling, (2) did not undergo any major cleaning afterward, and (3) was operated without the use of any biocide. A major cleaning is a protocol described and recommended by the fluid manufacturer and was performed on the three other machines, two of which were subsequently treated with biocides weekly. Fluid samples from the four lathes were collected weekly during a 6-month period, and total bacterial and cultivable Gram-negative bacteria were analyzed for each sample. Major cleaning of the machines (120–4) did not significantly reduce the concentration of bacteria in the cutting fluids when compared with the control machine (120–3), which had not undergone major cleaning. The concentrations of total bacteria were in the 10 6 CFU/mL range for these two lathes; however, a reduction in the total number of fluid changes was observed for this machine. Bacterial flora in the cutting fluids was significantly controlled with the use of biocides. Bacteria concentrations were in the 10 3 –10 5 CFU/mL range for the lathes with the use of biocides. Since thorough cleaning is insufficient and biocides are recognized as being responsible for some worker health problems, other avenues for controlling bacterial flora in cutting fluids should be evaluated to reduce worker exposure to their bacterial contaminants.

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.

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.

Fungal bioaerosols in biomethanization facilities

ABSTRACT Biomethanization is a new technology used for green-waste valorization where organic waste is biodegraded by microbial communities under anaerobic conditions. The main product of this type of anaerobic digestion is a biogas used as an energy source. Moving and handling organic waste may lead to the emission of high concentrations of bioaerosols. High exposure levels are associated with adverse health effects amongst green environment workers. Fungal spores are suspected to play a role in many respiratory illnesses. There is a paucity of information related to the detailed fungal diversity in biomethanization facilities. The aim of this study was to provide an in-depth description of fungal bioaerosols in biomethanization work environments using a next-generation sequencing approach combined with real-time polymerase chain reaction (PCR). Two biomethanization facilities treating different wastes were visited during the sampling campaign (n = 16). Quantification of Penicillium/Aspergillus and Aspergillus fumigatus revealed a greater exposure risk during summer for both facilities visited. Concentrations of Penicillium and Aspergillus were similar in all work areas in both biomethanization facilities. Taxonomy analyses showed that the type of waste treated affects the fungal diversity of aerosols emitted. Although eight classes were evenly distributed in all samples, Eurotiomycetes were more dominant in the first facility and Agaricomycetes were dominant in the second one. A large diversity profile was observed in bioaerosols from both facilities showing the presence of pathogenic fungi. The following fungi detected are known allergens and/or are opportunistic pathogens: Aspergillus, Malassezia, Emericella, Fusarium, Acremonium, and Candida. Daily exposure to these fungi may put workers at risk. The information from this study can be used as a reference for minimizing occupational exposure in future biomethanization facilities. Implications: Biomethanization is a new technology used for green-waste valorization where organic waste is biodegraded by microbial communities. Effective waste management is increasingly recognized as a strategic approach for achieving newly created regulations concerning the disposal of organic residues; therefore, an expansion of facilities is expected. Workers’ exposure to diverse fungal communities is certain, as fungi are ubiquitous and necessary in organic matter decomposition. Monitoring this occupational exposure is important in order to prevent workers’ health problems.

Bacteria emitted in ambient air during bronchoscopy—a risk to health care workers?

Background Health care workers are at risk of occupational infections, and some procedures are known to increase this risk. The aim of this study was to qualify and quantify bioaerosol concentrations during bronchoscopy to estimate the occupational risk. Methods Full-day sampling was conducted in 2 rooms while bronchoscopies were performed on patients. Two microbial air samplers were used, a wet wall cyclonic sampler and an impactor, on culture media. Identification of the culturable bacterial flora was performed with chromatographic analysis of cellular fatty acid of the isolated strain and additional biochemical tests if needed. Specific polymerase chain reaction analysis was completed on wet wall cyclonic samples for the detection of influenza A and B and Mycobacterium spp. Results A wide variety of bacteria were collected from the ambient air. All samples yielded at least 1 Staphylococcus species. Although most of the culturable bacteria identified were normal nonpathogenic flora, such as Streptococcus spp, Neisseria spp, and Corynebacterium spp, some opportunistic pathogens, such as Streptococcus pneumoniae, were found. Neither Mycobacterium spp nor influenza virus was detected with the polymerase chain reaction method during this study. Conclusions Culturable bacteria from oral, nasal, and pulmonary flora are aerosolized during bronchoscopy and could be inhaled by medical staff. The potential presence of pathogens in those aerosols could represent an occupational infection risk.

Efficacy of inhaled budesonide for the treatment of severe equine asthma

Summary Background Corticosteroids are the most potent drugs for the control of severe equine asthma, but adverse effects limit their chronic systemic administration. Inhaled medications allow for drug delivery directly into the airways, reducing the harmful effects of these drugs. Objectives To evaluate the efficacy of inhaled budesonide specifically formulated for the equine use and administered by a novel inhalation device in horses with severe asthma. Study design Experimental studies in horses with naturally occurring asthma with cross‐over, randomised, blinded experimental designs. Methods In Study 1, budesonide (1800 μg twice daily) administered using a novel Respimat® based inhaler was compared to i.v. dexamethasone (0.04 mg/kg). In Study 2, 3 doses of budesonide (450, 900, and 1800 μg) were compared to oral dexamethasone (0.066 mg/kg). Lung function, bronchoalveolar fluid cytology (Study 1), CBC, serum chemistry, and serum cortisol and adrenocorticotropic hormone (ACTH) values were evaluated. Results In Study 1, there was a marked and significant improvement in the lung function of all horses treated with budesonide and dexamethasone. Neutrophil percentages in bronchoalveolar fluid decreased in all horses treated with dexamethasone and in four of six horses treated with budesonide. Serum cortisol and blood ACTH concentrations decreased with both treatments. In Study 2, there was a significant improvement in the lung function with all dosages of budesonide, and the effects of higher dosages were comparable to those of dexamethasone. Dexamethasone and budesonide at the two higher dosages induced a significant decrease of cortisol concentrations. Main limitations The Respimat® based inhaler is not currently commercially available. Conclusions Administration of budesonide with the Respimat® based inhaler provided dose‐dependent relief of airway obstruction in horses with severe asthma, but also a suppression of serum cortisol.

Bronchoalveolar lavage fluid neutrophilia is associated with the severity of pulmonary lesions during equine asthma exacerbations

BACKGROUND The severe form of equine asthma is associated with pathological changes of the peripheral airways and pulmonary parenchyma that are only partly described. Also, the relationship between these structural alterations and the percentage of neutrophils found within the airway lumen, assessed by bronchoalveolar lavage fluid (BALF) cytology, remains ill-defined. OBJECTIVE To examine the histological lesions associated with equine asthma during disease exacerbation and remission, and their relationship with lung function and BALF neutrophilia. STUDY DESIGN Observational retrospective study. METHODS Peripheral lung tissues, BALF cytology and lung function data from 61 horses (22 controls, 24 asthma exacerbations and 15 asthma remission) were obtained from an equine pulmonary tissue bank. Two pathologists semi-quantitatively assessed histological features, including airway wall inflammation, interstitial fibrosis, mucus cell hyperplasia, mucostasis, peribronchiolar metaplasia, presence of granuloma and the overall severity of these lesions. RESULTS Mucostasis, mucus cell hyperplasia, peribronchiolar metaplasia and interstitial fibrosis were associated with disease exacerbation (P≤0.05), and these changes were all attenuated during remission. Airway wall inflammation was greater in horses with asthma in exacerbation compared with horses with asthma in remission and control horses (P≤0.05). Acute (neutrophilic) airway wall inflammation was more frequently detected in asthmatic cases compared with control horses (P<0.0001) and was associated with BALF neutrophilia >5% in control horses (P = 0.002). The degree of bronchiolar inflammation was higher in asthmatic horses in remission stabled and treated pharmacologically compared with those kept on pasture (P = 0.04). MAIN LIMITATIONS Samples obtained from a convenient cohort of horses were studied. CONCLUSIONS Severely asthmatic horses present parenchymal and peribronchial/peribronchiolar lesions possibly contributing to the obstructive nature of the disease.