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Biomedical subjects

D Bélanger

Publications and source records attributed to D Bélanger.

At least 19 recordsLinked to original sources
PubMed2005

Biochemical reference ranges for groups of ewes of different ages.

Reference biochemical ranges for young adult and adult ewes in mid-gestation were derived from 83 pooled serum samples taken from 30 flocks in the Province of Québec, Canada. In each flock the samples were pooled into three age categories and each category contained between six and 10 samples. The blood samples were taken by jugular venepuncture in December 1999. All the values were within the normal published ranges. As the age of the ewes increased there were slight increases in the concentrations of globulin and total protein and decreases in the concentrations of calcium, phosphorus, creatinine, glucose and albumin, and in the activities of alkaline phosphatase and glutathione peroxidase.

Aging↗
PubMed2001

Spatial variation in mercury concentrations in wild mink and river Otter carcasses from the James bay territory, Québec, Canada.

Mercury concentrations were analyzed in different organs/tissues of wild minks (Mustela vison) and river otters (Lutra canadensis) trapped during two seasons in the James Bay territory (49 degrees N to 55 degrees N, Québec, Canada). In 1993-94, mean total Hg concentration (microg/g, wet weight) in 39 wild mink and 12 river otter carcasses was greatest in fur/hair samples (30.1 and 20.7 microg/g, respectively) and least in brain samples (0.96 and 0.8 microg/g, respectively) with liver, kidney, and muscle samples showing intermediate values. Pooling data from the 1993-94 and 1994-95 trapping seasons revealed mean (SD) liver total Hg concentrations of 3.71 microg/g (3.91) in 316 wild mink carcasses and 4.05 microg/g (3.41) in 153 river otter carcasses. Log liver total Hg concentration increased with age in wild mink but not in river otter. Log liver total Hg concentration in each species was greatest in areas with moraine deposits and least in areas with rich clay deposits, but the effect of soil deposits could be confounded by uneven deposition of anthropogenic Hg. Controlling for type of soil deposits, log liver total Hg concentration decreased with increasing distance from local industrial centers in each species but varied little with changes in distance from hydroelectric reservoirs. In a subsample of carcasses from the moraine sector, log liver total Hg concentration was higher in wild mink than in river otter. Spatial variation in log liver total Hg concentration in relation to soil deposit type and proximity to industrial centers suggests that the two wild furbearer species could be useful indicators of environmental contamination.

Animals↗
PubMed2001

Allogeneic transplantation for multiple myeloma: further evidence for a GVHD-associated graft-versus-myeloma effect.

We report a series of 37 consecutive patients with multiple myeloma (MM) who received an allograft between 1990 and 2000 at our institution. Median age was 47 years, and nearly 70% of patients were Durie-Salmon stage III. A median of five cycles of chemotherapy were given before transplant, with a median interval between diagnosis and transplant of 9.3 months. We report a nonrelapse mortality rate of 22% with a median follow-up period of 40 months, whereas complete remission (CR) rate at 12 months is estimated at 57%. Treatment failure rate and overall survival at 40 months are estimated at 52% and 32%, respectively. The number of chemotherapy cycles prior to allotransplantation achieved borderline statistical significance as a poor prognosis factor for overall survival (P = 0.05), while the presence of chronic graft-versus-host disease (cGVHD) was significantly correlated with CR achievement (P = 0.036). Our study confirms that early allografting in MM can yield toxicity rates significantly lower than those associated with historical cohorts, and supports the hypothesis that cumulative chemotoxicity has a negative influence on mortality and survival rates. More importantly, our study clearly demonstrates an association between cGVHD and CR and brings further evidence in favor of a graft-versus-myeloma effect.

Adult↗
PubMed1999

Tau-mediated process outgrowth is differentially altered by the expression of MAP2b and MAP2c in Sf9 cells.

It is well documented that the MAPs, MAP2 and tau, play pivotal roles in neurite outgrowth. Several isoforms of MAP2 and tau are coexpressed in neurons, suggesting that the pattern of neurite outgrowth results from a functional equilibrium among these isoforms. In the present study, by coexpressing two of these MAPs at the same time in Sf9 cells, we demonstrated that tau-mediated process outgrowth is affected differently by MAP2b and MAP2c. MAP2b impairs tau ability to induce process outgrowth. Tau affects MAP2c capacity to induce the formation of multiple processes. There is evidence that actin microfilaments (F-actin) are involved in the elaboration of tau-mediated process outgrowth in Sf9 cells. We compared the effects of MAP2b and MAP2c with the effects of tau on F-actin distribution and stability in Sf9 cells. In MAP2b- and MAP2c-expressing cells with processes, F-actin was redistributed. However, in MAP2b-expressing cells without processes, the distribution of F-actin appears to be similar to the one in wild-type infected cells. Collectively, these results indicate that MAP2b could impair the ability of MAP2c and tau to redistribute F-actin in Sf9 cells, thereby decreasing their capacity to induce process formation. Furthermore, MAP2b and MAP2c patterns of process outgrowth were differentially modified by depolymerization of F-actin by cytochalasin D (CD). As previously reported for tau-expressing cells, the MAP2b-expressing cells developed a higher number of processes per cell and a higher number of cells presented processes in the presence of CD. However, the number of cells with multiple processes was lower in MAP2b-expressing cells than in tau-expressing cells treated with CD at 24 h postinfection. This suggests that MAP2b exerts an effect on F-actin stability at an earlier stage of infection than tau. MAP2c had also some stabilizing effects on F-actin at an early stage of infection, since the percentage of cells presenting one process was similar to the nontreated cells. Therefore, MAP2b seems to have less capacity than MAP2c to redistribute F-actin but, nonetheless, both of these MAP2 isoforms exert a stabilizing effect on F-actin at an early stage of infection. Finally, by modifying phosphorylation we showed that MAP2c capacity to induce multiple processes is related to protein phosphorylation in Sf9 cells. Therefore, the differential effect of MAP2c and MAP2b on process outgrowth seems also to depend on protein phosphorylation.

Actins↗
PubMed1999

Reproductive performance of two generations of female semidomesticated mink fed diets containing organic mercury contaminated freshwater fish.

Semidomesticated female mink (Mustela vison) were fed daily diets containing 0.1 ppm, 0.5 ppm, and 1.0 ppm of total mercury. Piscivorous and nonpiscivorous fish naturally contaminated with organic mercury were used to prepare the diets. Twenty-month-old females (G1 generation) that were exposed to the experimental diets for approximately 400 days in 1994 and 1995 and their 10-month-old female offspring (G2 generation) that were exposed to mercury for approximately 300 days in 1995, were all mated to 10-month-old males. Males were fed the diet containing 0.1 ppm mercury 60 days prior to the mating season. Diets containing 0.1 ppm and 0.5 ppm were not lethal to G1 and G2 females for an exposure period of up to 704 days. At the age of 11 months, mortalities occurred in 1994 for G1 females (30/50) and in 1995 for G2 females (6/7) fed the 1.0 ppm mercury diet after 90 days and 330 days of exposure, respectively. The length of the gestation periods and the number of kits born per female were not different among dietary groups for the two generations of females. The proportion of females giving birth was low for all groups, except for the G1 females fed the 0.1 ppm diet. There was an inverse relationship between whelping proportion and exposure group, but was not statistically significant. There was evidence that kits were exposed to mercury both in utero and/or during lactation as indicated by the presence of mercury in their livers. Mercury exposure did not influence the survival and growth of neonatal kits.

Animals↗
PubMed1999

Two different schedules for integrating filgrastim as adjuvant therapy in the treatment of patients with advanced stage Hodgkin's lymphoma receiving MOPP/ABV hybrid chemotherapy.

PURPOSE: Management of advanced-stage Hodgkin's disease with a MOPP/ABV hybrid regimen (mechlorethamine, vincristine, procarbazine, prednisone, Adriamycin, bleomycin and vinblastine) has yielded a high complete response rate (75-85%). However, myelosuppression can limit delivery of treatment. Filgrastim has been shown to reduce chemotherapy-related neutropenia and allow for on-time administration of planned doses of chemotherapeutic agents. The objective of this study was to find the best way to integrate filgrastim with the MOPP/ABV hybrid regimen. METHODS: Enrolled in this study were 24 patients (aged 18-52 years) with newly diagnosed, histologically documented Hodgkin's disease. In schedule I, patients received filgrastim (5 microg/kg s.c. daily) beginning on day 9, 24 h after administration of ABV. In schedule II, patients received filgrastim concomitantly with procarbazine on days 2-7 (starting 24 h after day-1 MOPP administration and stopping 24 h before ABV administration) as well as after ABV beginning on day 9. Filgrastim after ABV administration was administered until two consecutive ANC readings of 10 x 10(9)/l were achieved. RESULTS: All patients were able to complete all six cycles of therapy. There was a trend to fewer dose reductions in schedule II (0.76%) as compared to schedule I (4.2%) with a P-value of 0.077 (chi-squared test). Specifically, 11.6% of MOPP courses and 5.5% of ABV courses were dose-reduced in schedule I versus 1.7% and 1.4%, respectively, in schedule II. CONCLUSION: In conclusion, filgrastim was effective in supporting the delivery of the MOPP/ABV chemotherapy. Concomitant administration of filgrastim with procarbazine (days 2-7) appears to be safe and allows the maximum dose intensity of this therapy.

Adolescent↗
PubMed1997

Determination of gestational age in sheep and goats using transrectal ultrasonographic measurement of placentomes.

Three experiments were conducted to determine gestational age in the ewe and doe by measuring placentomes with a B-mode ultrasonograph and a 5 MHz transducer. Transrectal measurements were obtained by placing the female over a bale of hay. In Experiment 1, ewes (n = 12) and does (n = 15) were examined by transrectal ultrasonography every week from breeding to parturition to determine the growth pattern of placentomes during pregnancy. In Experiment 2, placentomes from 132 ewes and 169 does were measured between 30 and 90 d of gestation. A linear regression relationship between fetal age in days and placentome size in mm was calculated and adjusted for does (gestational age = 28.74 + 1.80PL + e, r(2) = 70.34) and for ewes (age = 47.98 + 0.62PL + e, r(2) = 15.59). In Experiment 3, the placentomes of 63 does were measured to validate this relationship by using linear regression. Gestational age was determined correctly in 66% of the does, with a range of +/- 7 d and in 96% with a margin of +/- 14 d. In conclusion, transrectal ultrasonography allowed for the measurement of placentome size, which increased rapidly during the first 70 to 90 d of gestation in ewes and does. In ewes, however, there was a poor correlation of placentome size with gestational age, while in goats, measurement of placentomes could be used along with pregnancy diagnosis by transrectal ultrasonography as an indication of gestation age.

Journal Article↗
PubMed1997

A processing plant survey of external lesions of American eels (Anguilla rostrata) from Lake Ontario and the St. Lawrence River, Canada.

Signs of decreasing landing and recruitment were observed in the last decade in American eels (Anguilla rostrata) from the St. Lawrence River basin, Canada. In order to verify if the declines were associated with high prevalence of diseases among commercial catches, a total of 12243 eels captured in five commercial fishing sites were inspected at two processing plants in 1992. They were all examined for external lesions and palpated to detect vertebral deformities. Eels from Lakes Ontario, Saint-François and Saint-Pierre were mainly resident eels, while those from the Richelieu River and the St. Lawrence Estuary at Kamouraska were mainly mature migrating eels. Prevalences of every lesion observed were low (< or = 1%) at every site. Scratches all over the body were found only on eels from Kamouraska. Cutaneous ulcers were observed more frequently in the Richelieu River. Higher prevalences of vertebral deformities were found in mature migrating eels captured in Kamouraska and in the Richelieu River. Vertebral deformities were also observed more frequently among eels captured at the end of the 1992 fishing season in Kamouraska. Higher length, weight and/or age of mature migrating eels may be associated with higher prevalences of vertebral deformities among this group. These results do not indicate that the health of the American eels commercially captured in the St. Lawrence basin is severely impaired. However, the magnitude of diseases among the biological population is probably underestimated by such a survey.

Aging↗
PubMed1997

A telephone survey of eel fishermen regarding external lesions and mortalities of American eels (Anguilla rostrata) from Lake Ontario and the St. Lawrence River basin, Canada.

Signs of decreasing landings and recruitment have been observed during the last decade in American eels (Anguilla rostrata) from the St. Lawrence River basin, Canada. A study was undertaken to examine whether important manifestational diseases among commercial catches could be associated with these declines. During this survey, 56 fishermen from Lakes Ontario, Saint-François and Saint-Pierre, the Richelieu River, the Québec City area and the St. Lawrence Estuary were interviewed. Most fishermen from every area reported decreasing catches since the 1980s. Eel mortalities were reported from 1990 to 1992 in Lake Saint-François, Lake Saint-Pierre and the Québec City area, but in apparently lower magnitude than in the past decades. The lesions observed on dead eels in Lake Saint-François indicated that the cause of the mortalities might be associated with the upstream hydroelectric dam. Eels with 'scratches all over the body' were only observed in the St. Lawrence Estuary. Fishermen from almost every area reported that they had observed eels with 'crooked tail', 'humpback' and 'cut tail' in low frequency in 1992. The questionnaire data were validated by comparing some of the results of the questionnaire survey and a processing plant survey in 1992. The use of questionnaires for assessing fish diseases in commercial species is discussed. The results of this survey do not indicate that the health of the American eels from the St. Lawrence River basin is severely impaired. However, the magnitude of diseases and mortalities was probably underestimated.

Anguilla↗
PubMed1997

Ecosystem health as a clinical rotation for senior students in Canadian veterinary schools.

We describe 4 years of an experimental rotation in ecosystem health offered to senior veterinary students in Canada. Faculty from the 4 Canadian veterinary colleges collaborated in offering the rotation once annually at 1 of the colleges. The 1st rotation was held in Guelph in 1993, followed in successive years by rotations at Saskatoon, Saint-Hyacinthe, and Charlottetown. The rotation is a predominantly field-based experience that allows students to work with veterinary and other role models who are actively engaged in clinical research related to ecosystem health. Five specific field studies that worked particularly well during the rotations are presented. These studies involved investigating mortality in wildlife due to botulism, designing an environmental surveillance system around herds of beef cattle, using belugas to evaluate the health of the St. Lawrence River, dealing with competition for water use by aquaculture and agriculture, and exploring the role of veterinarians during major coastal oil spills. The experience has resulted in our developing the subject matter, field examples, teaching approach, and confidence necessary to make ecosystem health the focus of a productive clinical rotation for senior year veterinary students.

Agriculture↗
PubMed1996

Urinary protein excretion of semidomesticated mink in a chronic methylmercury study.

A model using semidomesticated mink was set up to study the effects of chronic oral methylmercury exposure in piscivorous mammals. Three groups of mink were fed daily with diets containing approximately 0.1, 0.5, and 0.9 micrograms/g of total mercury. Piscivorous and non-piscivorous fish, naturally contaminated with methylmercury, were used to prepare diets. Renal injury was evaluated using total urine protein/creatinine ratio and differentiation of urinary low-molecular-weight and high-molecular-weight proteins on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The significance of the total urine protein/creatinine ratio data was assessed by comparing the results to a 95% group-based reference interval. The values for total urine protein/creatinine ratio did not reveal any significant increased excretion, and no dose-related trends were observed within the reference interval. Overall the total urine protein data did not suggest renal damage. Analysis of the SDS-PAGE electrophoretograms did not suggest the presence of any persistent glomerular damage in any group. High-molecular-weight proteins were not detected more frequently for any of the dose groups. During the adaptation phase, the B2M-like protein band was not remarked during the visual analysis of the gels. The B2M-like protein band was remarked during the gel analysis only several weeks into the exposure phase. This B2M-like protein band was more prevalent in urine samples taken from minks in the 0.5 and 0.9 micrograms/g groups than in the 0.1 microgram/group. These latter data, however, did not allow an evaluation of a quantitative dose-response excretion with time. The B2M-like data are suggestive of very minor renal injury.

Albuminuria↗
PubMed1995

Importance of Escherichia coli in young beef calves from northwestern Quebec.

The objectives of this study were: (i) to investigate the prevalence of Escherichia coli producing F5 (K99), F41, or F165 fimbriae and STa enterotoxin; (ii) to determine serum antibody levels against these fimbriae; (iii) and to examine the association between bacteriological and serological results and the presence of diarrhea, in beef calves from northwestern Quebec. A total of 373 live three to four week old calves and 27 dead calves were sampled between January and March 1991. No isolates positive for F5 were detected in live calves, and only one E. coli producing STa and F41 was isolated. Escherichia coli producing F41-like surface antigens or F165 fimbriae were isolated from 17.43% and 5.63% of live calves, respectively. Antibodies against F5, F41 and F165 were low. Escherichia coli isolates positive for F41-like surface antigen were most often observed in calves born between January and March. No association was found between bacteriological and serological findings, nor between these findings and diarrhea. Calves born from dams vaccinated against E. coli had higher median antibody levels than those born from unvaccinated dams. No E. coli positive for F5 or F41 fimbriae were isolated from dead calves. Escherichia coli with F41-like surface antigen or F165 were found in 55.56% and 11.11% of ileal samples; 4% and 16% of cecal samples, and 0% and 7.4% of colon samples, respectively. Escherichia coli positive for F41-like surface antigen were detected significantly more frequently in the ileum (chi (2)2df = 31.01, p < 0.001).

Animals↗
PubMed1995

A seroepidemiological study of the importance in cow-calf pairs of respiratory and enteric viruses in beef operations from northwestern Quebec.

Serum antibody analyses for bovine herpesvirus type 1 (BHV-1), bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV), bovine coronavirus (BCV), and bovine rotavirus (BRV) were performed on 527 randomly selected cows, before calving, and on 407 three-week-old calves. In cows and calves, BCV and BRV were the most seroprevalent viruses (80% to 100% according to virus and vaccination status). Bovine respiratory syncytial virus was the least seroprevalent in the cows, independent of the vaccination status. In nonvaccinated cows the seroprevalence to BRSV was 36.7%, and 53.5% in cows vaccinated less than two weeks prior to collecting blood, and 67.6% in cows vaccinated two weeks or more prior to blood collection. In their calves, BHV-1 was the least seroprevalent, independent of the vaccination status. The serological status and antibody titers in calves were generally associated with those of the dam. The occurrence of respiratory diseases in the calves was associated with cow and calf serological profiles (BHV-1, BRSV and BCV in the nonvaccinated group, BHV-1, BVDV and BCV in the vaccinated group). The occurrence of diarrhea was not associated with cow and calf serological profiles but was negatively associated with high level calf serum IgG in the nonvaccinated group (odds ratio = 0.73). Bovine coronavirus and BRV were shed by 1.4% and 4.9% of calves in the nonvaccinated group, and by 0% and 9.9% of calves in the vaccinated group, respectively. Bovine rotavirus shedding was associated with fecal diarrheic consistency at the moment of fecal sampling but not with previous occurrence of diarrhea.

Animals↗
PubMed1994

[Cesarians on dairy cows: 159 cases].

A retrospective study on 159 cesareans on dairy cows referred between 1985 and 1989 to the veterinary teaching hospital is reported. The objective of the study was to evaluate the probability and the factors associated with survival and subsequent calving. The risk of dying for the cows was 24% following surgery. The risk of dying differed if the cow had an emphysematous, dead, or live calf; it was 63%, 21%, and 14%, respectively. Of all the cows returned to the farm and for which there was a breeding recorded, 64% calved again. But only 28% of all the cows returned home and, therefore, only 17% of all the referred cases calved again. We used multivariate analysis to obtain a predictive model on prognosis following surgery. The prognosis was only influenced by the calf condition at admission.

Animals↗
PubMed1991

Radiographic, high detail radiographic, microangiographic and histological findings of the distal portion of the tarsus in weanling, young and adult horses.

Clinical radiographic (LM and D35L-P1MO views), high detail radiographic, microangiographic and histological findings of the distal portion of the tarsus of 16 horses (five weanling, four young and six adult), without known clinical histories, were evaluated to determine the sensitivity of clinical radiographs for the detection of abnormalities in the distal tarsus and the prevalence of abnormalities in this population. Clinical radiographic and high detail radiographic abnormalities were observed in at least 30 per cent of the tarsi examined. Statistical agreement between observations from clinical radiographs and corresponding post mortem high detail radiographs was not good for subchondral bone plate irregularities and joint margin changes. Three patterns of sclerosis of the medullary spongiosa were visualised on high detail radiographs: thickening of the subchondral bone plate was seen commonly in the weanling group, whereas arching and bridging patterns were more prevalent in the young and adult groups. Bone production on the dorsal cortex of the central and third tarsal bones did not increase with age. Abnormalities in vascular perfusion and articular cartilage histology were observed in association with subchondral bone plate irregularities and focal regions of osteopenia observed on high detail radiographs.

Aging↗
PubMed1990

Optimization of a polypyrrole glucose oxidase biosensor.

An amperometric glucose biosensor was fabricated by the electrochemical polymerization of pyrrole onto a platinum electrode in the presence of the enzyme glucose oxidase in a KCl solution at a potential of +0.65 V versus SCE. The enzyme was entrapped into the polypyrrole film during the electropolymerization process. Glucose responses were measured by potentiostating the enzyme electrode at a potential of +0.7 V versus SCE in order to oxidize the hydrogen generated by the oxidation of glucose by the enzyme in the presence of oxygen. Experiments were performed to determine the optimal conditions of the polypyrrole glucose oxidase film preparation (pyrrole and glucose oxidase concentrations in the plating solution) and the response to glucose from such electrodes was evaluated as a function of film thickness, pH and temperature. It was found that a concentration of 0.3 M pyrrole in the presence of 65 U/ml of glucose oxidase in 0.01 M KCl were the optimal parameters for the fabrication of the biosensor. The optimal response was obtained for a film thickness of 0.17 microns (75 mC/cm2) at pH 6 and at a temperature of 313 K. The temperature dependence of the amperometric response indicated an activation energy of 41 kJ/mole. The linearity of the enzyme electrode response ranged from 1.0 mM to 7.5 mM glucose and kinetic parameters determined for the optimized biosensors were 33.4 mM for the Km and 7.2 microA for the Imax. It was demonstrated that the internal diffusion of hydrogen peroxide through the polypyrrole layer to the platinum surface was the main limiting factor controlling the magnitude of the response of the biosensor to glucose. The response was directly related to the enzyme loading in the polypyrrole film. The shelf life and the operational stability of the optimized biosensor exceed 500 days and 175 assays, respectively. The substrate specificity of the entrapped glucose oxidase was not altered by the immobilization procedure.

Biosensing Techniques↗