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Biomedical subjects

C Infante-Rivard

Publications and source records attributed to C Infante-Rivard.

At least 19 recordsLinked to original sources
PubMed2005

Is metal fume fever a determinant of welding related respiratory symptoms and/or increased bronchial responsiveness? A longitudinal study.

BACKGROUND: The current prospective study investigated the hypothesis of metal fume fever (MFF) being a predictor for the development of respiratory symptoms and functional abnormalities. METHODS: The study consisted of a pre-exposure and two follow up assessments of 286 welding apprentices during an average period of 15 months. A respiratory and a systemic symptom questionnaire, skin prick tests to common allergens and metal salts, spirometry, and methacholine challenge tests were administered. RESULTS: Developing at least one positive skin prick test to a metallic salt solution was found in 11.8% of apprentices. Possible MFF (at least one of fever, feelings of flu, general malaise, chills, dry cough, metallic taste, or shortness of breath) was reported by 39.2% of apprentices. The presence of at least one welding related respiratory symptom (cough, wheezing, or chest tightness) suggestive of welding related asthma was reported by 13.8%. MFF was significantly associated with these respiratory symptoms (OR = 4.92, 95% CI 2.10 to 11.52), after adjusting for age, atopy, smoking, physician diagnosed asthma, and symptoms of non-welding related asthma. Apprentices with possible MFF, and no welding related respiratory symptoms suggestive of welding related asthma at the first follow up, had an increased risk of developing the latter symptoms by the second follow up visit (OR = 7.4, 95% CI 1.97 to 27.45) compared with those not having MFF. MFF was not significantly associated with an increase in bronchial responsiveness. CONCLUSION: MFF could be a predictor for the development of respiratory symptoms but not for functional abnormalities in welders.

Adult↗
PubMed2003

Reference values for an index of fetal aortic isthmus blood flow during the second half of pregnancy.

OBJECTIVE: During fetal life, the parallel position of the two cardiac ventricles confers a special status to the aortic isthmus. Flow through the isthmus reflects the balance between the performances of the two ventricles and their respective peripheral impedances. This study proposes a fetal aortic isthmus flow velocity index and its reference values defined on the basis of gestational age (GA). METHODS: Video recordings of 111 normal fetuses from 18 to 39 weeks of gestation were retrospectively reviewed. An isthmus flow velocity index (IFI) was calculated as follows: IFI = (systolic + diastolic)/systolic velocity integrals. GA-specific reference ranges of IFI were constructed. RESULTS: An IFI of 1.33 +/- 0.03 was found at 18 weeks. This value decreased slightly but steadily with GA to reach 1.23 +/- 0.16 at 39 weeks. This change is mainly related to a decrease in diastolic velocity integrals. CONCLUSION: The proposed IFI provides information on the direction and, indirectly, on the volume of blood flow through the fetal aortic isthmus.

Aorta, Thoracic↗
PubMed2003

Prevalence and association of welding related systemic and respiratory symptoms in welders.

BACKGROUND: The prevalence of welding related respiratory symptoms coexisting with welding related systemic symptoms in welders is unknown. AIMS: To determine in a sample of welders the prevalence of coexisting welding related systemic symptoms indicative of metal fume fever (MFF) and welding related respiratory symptoms suggestive of occupational asthma (OA), and the strength and significance of any association between these two groups of symptoms. METHODS: A respiratory symptoms questionnaire, a systemic symptoms questionnaire, and a questionnaire on occupational history were administered by telephone to 351 of a sample of 441 welders (79.6%) from two cities in Québec, Canada. RESULTS: The co-occurrence of possible MFF (defined as having at least two symptoms of fever, feelings of flu, general malaise, chills, dry cough, metallic taste, and shortness of breath, occurring at the beginning of the working week, 3-10 hours after exposure to welding fumes) together with welding related respiratory symptoms suggestive of OA (defined as having at least two welding related symptoms of cough, wheezing, and chest tightness) was 5.8%. These two groups of symptoms were significantly associated (chi(2) = 18.9, p < 0.001). CONCLUSION: There is a strong association between welding related MFF and welding related respiratory symptoms suggestive of OA. As such, MFF could be viewed as a pre-marker of welding related OA, a hypothesis that requires further investigation.

Adult↗
PubMed2003

Incidence of probable occupational asthma and changes in airway calibre and responsiveness in apprentice welders.

The majority of cross-sectional studies have shown a higher prevalence of ventilatory impairment in welders while only few longitudinal studies were able to detect chronic effects on spirometry or bronchial responsiveness. The aim of the study was to determine the incidence of probable occupational asthma (OA), bronchial obstruction and hyperresponsiveness among 286 students entering an apprenticeship programme in the welding profession. This epidemiological prospective cohort study consisted of a baseline assessment survey and two follow-up assessments. A respiratory symptom questionnaire was administered at each visit. Spirometry and methacholine bronchial challenge test results, conducted once prior to onset of exposure and later after an average of 15 months of apprenticeship, were available for 194 subjects. The incidence of probable OA was approximately 3% (6 of 194). The incidence of bronchial hyperresponsiveness, defined as a > or = 3.2-fold decrease in the provocative concentration causing a 20% fall in the forced expiratory volume in one second from baseline to the end of the study was 11.9%. A statistically significant difference was found between the baseline and end of study for the lung function values. In particular, the forced expiratory volume per cent predicted had significantly dropped by 8.4% on average. The significance of these early pulmonary function changes in relation to possible chronic effects of exposure to welding fumes and gases remains to be explored.

Adult↗
PubMed2002

Individual estimation of exposures to extremely low frequency magnetic fields in jobs commonly held by women.

Exposures to extremely low frequency (ELF) magnetic fields have not been documented extensively in occupations besides the work environments of electric or telephone utilities. A 1980-1993 study of childhood acute lymphoblastic leukemia (ALL) in Québec, Canada, gathered detailed information about the occupations of 491 mothers of ALL cases and mothers of a similar number of healthy controls. This information was combined with published data on the intensities of ELF magnetic fields associated with sources or work environments to estimate ELF magnetic field exposures for a wide range of jobs commonly held by women. Estimated exposures for 61 job categories ranged from 0.03 to 0.68 microT; the 25th, 50th, and 75th percentiles were 0.135, 0.17, and 0.23 microT, respectively. By job category, the most highly exposed jobs (>0.23 microT) included bakery worker, cashier, cook and kitchen worker, electronics worker, residential and industrial sewing machine operator, and textile machine operator. By work environment, the most highly exposed job categories were electronics worker in an assembly plant (0.70 microT) and sewing machine operators in a textile factory (0.68 microT) and shoe factory (0.66 microT). These results provide new information on expected levels of exposure in a wide range of jobs commonly held by women.

Adult↗
PubMed2002

Incidence and host determinants of work-related rhinoconjunctivitis in apprentice pastry-makers.

BACKGROUND: The authors recently assessed the incidence and determinants of immunologic sensitization to flour in apprentice pastry-makers. The aim of this work was to determine the incidence of work-related rhinoconjunctivitis (RC) symptoms and their determinants. METHODS: For this 188/230 entrants (81.7%) were evaluated before starting exposure to flour, and again 10.8 and 16.8 months after. Questionnaires and skin prick testing to common and work-related allergens were administered at each visit. Bronchial responsiveness to methacholine was assessed at baseline in all subjects and in a subgroup at follow-up. RESULTS: Thirty subjects (16.1%) reported new work-related RC symptoms (13.1 per 100 person-years); in three subjects (1.6%), these were accompanied by incident skin prick test reactivity to flour-derived allergens. Skin prick test reactivity to grass pollens (OR = 3.0, 95% CI, 1.3-6.7) and to pets (OR = 2.5, 95% CI, 1.1-5.9), persistent rhinitis (OR = 3.1, 95% CI, 1.1-8.4), seasonal RC (OR = 2.5, 95% CI, 1.1-5.5), RC on contact with pets (OR = 2.3, 95% CI, 1.03-5.0) and skin prick test reactivity to wheat flour (OR = 10.5, 95% CI, 2.3-46.8), assessed at baseline, were significantly associated with the incidence of work-related RC symptoms. Multivariate logistic regression analysis yielded significant OR of skin prick test reactivity to wheat flour at baseline (OR = 7.1, 95% CI, 1.7-35.1) and persistent rhinitis (OR = 3.9, 95% CI, 1.01-9.6) for the incidence of work-related RC symptoms. Increased bronchial hyperresponsiveness at follow-up was more frequent, although not significantly, in subjects positive to skin prick test to flour on entry and reporting new work-related symptoms (3/5), than in other subjects (4/17). CONCLUSIONS: The incidence of work-related RC symptoms among apprentice pastry-makers was high (16.1% 30/186), while a minority (3/30) also developed skin prick test reactivity to flour. Skin prick test reactivity to wheat flour and persistent allergic rhinitis on starting exposure to flour are significant determinants for the development of work-related RC symptoms.

Adolescent↗
PubMed2002

Effectiveness of the hands-free technique in reducing operating theatre injuries.

BACKGROUND: Operating theatre personnel are at increased risk for transmission of blood borne pathogens when passing sharp instruments. The hands-free technique, whereby a tray or other means are used to eliminate simultaneous handling of sharp instruments, has been recommended. AIMS: To prospectively evaluate the effectiveness of the hands-free technique in reducing the incidence of percutaneous injuries, contaminations, and glove tears arising from handling sharp instruments. METHODS: For each of 3765 operations carried out in main and surgical day care operating theatres in a large urban hospital, over six months, circulating nurses recorded the proportion of use of the hands-free technique during each operation, as well as other features of the operation. The hands-free technique, considered to be used when 75% or more of the passes in an operation were done in this way, was used in 42% of operations. The relative rate of incidents (percutaneous injuries, contaminations, and glove tears) in operations where the hands-free technique was used and not used, with adjustment via multiple logistic regression for the different risk profiles of the two sets of operations, was calculated. RESULTS: A total of 143 incidents (40 percutaneous injuries, 51 contaminations, and 52 glove tears) were reported. In operations with greater than 100 ml blood loss, the incident rate was 4% (18/486) when the hands-free technique was used and 10% (90/880) when it was not, approximately 60% less. When adjusted for differences in type and duration of surgery, emergency status, noisiness, time of day, and number present for 75% of the operation, the reduction in the rate was 59% (95% CI 23% to 72%). In operations with less than 100 ml blood loss, the corresponding rates were 1.4% (15/1051) when the hands-free technique was used and 1.5% (19/1259) when it was not used. Adjustment for differences in risk factors did not alter the difference. CONCLUSIONS: Although not effective in all operations, use of the hands-free technique was effective in operations with more substantial blood loss.

Accidents, Occupational↗
PubMed2002

Host determinants for the development of allergy in apprentices exposed to laboratory animals.

The aim of this study was to evaluate whether determinants of work-related symptoms, skin sensitization and diseases differ between atopic and nonatopic subjects starting a career with exposure to laboratory animals (LA). A cohort of 417 apprentices in animal-health technology was prospectively followed during 32 or 44 months. The effect on the study outcomes of variables derived from questionnaire, skin reactivity, and lung function assessments at baseline were compared in atopic (n=212) and nonatopic (n=183) subjects. Eighty-five incident cases of sensitization to a LA-derived allergen were identified, 67 among atopic and 18 among nonatopic subjects. Baseline rhinitis symptoms in contact with pets and skin sensitization to pets were associated with the development of work-related rhinoconjunctivitis (RC) symptoms in atopic subjects, whereas perannual rhinitis symptoms and having a PC20 (provocative concentration causing a 20% fall in forced expiratory volume in one second) < or = 32 mg x mL(-1) were associated in nonatopic subjects. Baseline rhinitis symptoms on contact with pets and a PC20 value < or = 32 mg x mL(-1) were significant determinants for developing sensitization to a specific allergen in atopic subjects only. Finally, baseline rhinitis symptoms in contact with pets and perannual rhinitis symptoms were associated with the development of occupational RC in atopic subjects, whereas in nonatopic subjects this was associated with having a PC20 value < or = 32 mg x mL(-1). In conclusion, the determinants for the development of specific skin sensitization, symptoms and disease are different between atopic and nonatopic apprentices starting occupational exposure to laboratory-animal-derived allergens.

Animals↗
PubMed2001

Family size, day-care attendance, and breastfeeding in relation to the incidence of childhood asthma.

A hypothesis has been suggested stating that children exposed early to infections are less likely to develop atopy or asthma. The authors investigated the relation between risk of childhood asthma and number of siblings as well as day-care attendance, as factors possibly increasing the likelihood of early infections, and breastfeeding as a factor reducing them. A case-control study was carried out in Montréal, Canada, between 1988 and 1995 that included 457 children diagnosed with asthma at 3--4 years of age and 457 healthy controls. Cases followed for 6 years were later classified as persistent or transient by the symptoms and use of medication after diagnosis. Among cases diagnosed at 3--4 years of age, the adjusted odds ratio for asthma was 0.54 (95% confidence interval (CI): 0.36, 0.80) for one sibling and 0.49 (95% CI: 0.30, 0.81) for two or more. The adjusted odds ratio for day-care attendance before 1 year of age was 0.59 (95% CI: 0.40, 0.87). Results were similar with persistent cases. Among transient cases (who possibly had an infection with wheezing at 3--4 years of age), day-care attendance and a short duration of breastfeeding resulted in increased risk. The results support the hypothesis that opportunity for early infections reduces the risk of asthma.

Asthma↗
PubMed2001

Quantifying and reducing the risk of bloodborne pathogen exposure.

The risk of becoming infected with bloodborne pathogens (e.g., hepatitis B, hepatitis C, HIV) during surgery is real. The degree of risk for perioperative personnel is related to factors that include participating in large numbers of surgical procedures each year; the nature of perioperative work (e.g., use of different types of sharp instruments): exposure to large amounts of blood and body fluids; the prevalence of bloodborne pathogens in the surgical population; the variation in different organisms' ability to be transmitted; the existence of vaccines and the level of vaccination; the availability of postexposure treatment; and the consequences of acquiring the disease. Controlling risks to perioperative personnel can be accomplished by using the Occupational Safety and Health Administration's three methods of control--redesigning surgical equipment and procedures, changing work practices, and enhancing the personal protection equipment of perioperative personnel.

Blood-Borne Pathogens↗
PubMed2001

Incidence of sensitization, symptoms, and probable occupational rhinoconjunctivitis and asthma in apprentices starting exposure to latex.

Latex is a well-known sensitizer. Prospective studies in apprentices beginning to be exposed to latex have not been carried out. We wanted to determine the incidence of skin reactivity, cutaneous symptoms, rhinoconjunctivitis (RC) symptoms, respiratory symptoms, probable occupational RC, and asthma in apprentices in dental hygiene. A total of 122 students starting a program in dental hygiene technology were recruited between 1993 and 1995. A questionnaire, skin-prick tests with common aeroallergens and latex, and assessment of spirometry and responsiveness to methacholine were carried out on entry and at follow-up visits at 20 and 32 months after the start of exposure. Of the 110 subjects who participated for at least 1 follow-up visit, skin reactivity to latex developed in 7. Cutaneous symptoms developed in 6 of the 7, RC symptoms developed in 2, and respiratory symptoms developed in 1. Five of the 7 subjects had significant changes in methacholine responsiveness and fulfilled the definition of probable occupational asthma. Sensitized subjects were more likely to be atopic and to have a previous history of asthma and respiratory symptoms on exercise than were nonsensitized subjects. Three subjects at the 20-month assessment and 4 subjects at the 32-month visit showed skin reactivity. The cumulative incidences for skin sensitization, probable occupational RC, and occupational asthma to latex were 6.4%, 1.8%, and 4.5%, respectively.

Adolescent↗
PubMed2001

Correlation between prenatal velocity waveforms in the aortic isthmus and neurodevelopmental outcome between the ages of 2 and 4 years.

OBJECTIVE: Experimental studies on fetal lambs have shown that during an increase in the resistance to placental flow the delivery of oxygen to the brain is preserved as long as net flow through the aortic isthmus is antegrade. Our purpose was to determine whether the same changes in aortic isthmus flow in human subjects have any impact on neurodevelopmental outcome. STUDY DESIGN: Forty-four fetuses were retrospectively included in this study on the basis of an abnormal Doppler velocity in the umbilical artery. Mean gestational age at delivery was 33.0 +/- 2.0 weeks and mean birth weight 1386 +/- 435 g. The neurodevelopmental condition was assessed between the ages of 2 and 4 years. The developmental score was analyzed in relation to the flow patterns in the fetal aortic isthmus, which were classified as follows: group A, net isthmic flow antegrade (defined as the ratio of the systolic antegrade to the diastolic retrograde velocity integrals) (n = 39); group B, net isthmic flow retrograde (n = 5). RESULTS: Nonoptimal neurodevelopment was observed in 19 (49%) of 39 fetuses in group A and in all 5 fetuses (100%) in group B. This difference is significant and leads to a relative risk of 2.05 (95% confidence interval, 1.49-2.83) for neurodevelopmental deficit when predominantly retrograde flow is observed in the fetal aortic isthmus before birth. CONCLUSION: Measuring the ratio of antegrade to retrograde velocity integrals in the aortic isthmus could help in the indirect assessment of cerebral oxygenation during placental circulatory insufficiency.

Aorta↗
PubMed2001

Congenital anomalies in children with acute lymphoblastic leukaemia and in their family.

BACKGROUND: With the exception of Down syndrome the association between congenital anomalies and acute lymphoblastic leukaemia (ALL) is presently unclear. We investigated this association in a population-based case-control study carried out in the province of Québec, CANADA: METHODS: A total of 491 incident cases diagnosed between 1980 and 1993 and aged 0-9 years were included in the study. Healthy controls (n = 491) matched on age, sex, and region of residence at the time of diagnosis were selected from government family allowance files. Using a structured questionnaire and the International Classification of Diseases (Ninth Revision) list of congenital anomalies, presence of an anomaly was determined by interviewing the parents of the study subjects; mothers gave information on anomalies in the study subject, their siblings and her family, whereas fathers provided information on anomalies in their family. RESULTS: The adjusted risk for ALL was not increased in children who had any anomaly (odds ratio [OR] = 1.07 [95% CI : 0.70-1.65]) whereas compared to control siblings, case siblings had a higher risk of anomalies (OR = 1.54, 95% CI : 0.99- 2.42). This increase was likely due to excesses in anomalies of the heart (OR = 2.49, 95% CI : 1.23-5.04). Risk for ALL was elevated in children with a history of a congenital anomaly in their mother (OR = 1.61, 95% CI : 0.80-3.22) or her family (OR = 1.45, 95% CI : 0.94-2.25). CONCLUSIONS: Although based on small numbers for specific anomalies, these findings suggest that congenital anomalies are more prevalent in siblings and maternal family of ALL cases than in controls.

Case-Control Studies↗
PubMed2001

Drinking water contaminants and childhood leukemia.

We conducted a population-based case-control study to evaluate the relation between exposure to drinking water contaminants (total and specific trihalomethanes and certain metals and nitrates) and childhood acute lymphoblastic leukemia. We compared 491 cases 0-9 years of age with 491 controls. We developed a municipality-exposure matrix based on municipal and provincial historical data, a tapwater survey in 227 homes, and information about residential history. We used average level of exposure and cumulative average over the period as exposure indices, and we measured risk for the pregnancy period as well as for the postnatal period. We show that risks were generally not increased for the prenatal period nor with average levels of exposure. Postnatal cumulative exposure for total trihalomethanes at above the 95th percentile of the distribution for cases and controls was associated with an odds ratio of 1.54 (95% confidence interval = 0.78-3.03); for that same period, risk associated with exposure to chloroform was increased (odds ratio = 1.63; 95% confidence interval = 0.84-3.19) as well as that for exposure to zinc (odds ratio = 2.48; 95% confidence interval = 0.99-6.24). Risks were also increased for exposure to cadmium and arsenic, but not for other metals nor for nitrates.

Case-Control Studies↗
PubMed2001

Incidence and host determinants of probable occupational asthma in apprentices exposed to laboratory animals.

Laboratory animal (LA) workers are frequently affected with allergic sensitization and occupational asthma (OA). The role of preexposure host factors, in particular airway responsiveness, on the incidence of OA has not been satisfactorily studied. A prospective cohort study of 417 apprentices in animal-health technology was conducted to investigate the incidence and determinants of probable OA. Questionnaire and skin-prick tests with common and work-specific allergens were administered on entry and at follow-up visits (up to three) from 8 to 44 mo after starting apprenticeship. Responsiveness to inhaled methacholine was assessed at baseline and at follow-up in apprentices who developed a new specific skin sensitization and in control subjects. Preexposure host characteristics and the school attended were compared between cases and all cohort subjects not meeting the criteria for probable OA. Twenty-eight apprentices satisfied the definition for probable OA, i.e., onset of immediate skin reactivity to > 1 occupational inhalant and > 3.2-fold decrease in the provocative concentration causing a 20% reduction in FEV(1) (PC(20)). The incidence of probable OA was 2.7% (28/1,043 person-years). Baseline immediate skin reactivity to pets (rate ratio [RR] 4.1, 95% confidence interval [CI] = 1.6 to 10.8), and bronchial responsiveness (PC(20) < or = 32 versus PC(20) > 32 mg/ ml) (RR = 2.5, 95% CI = 1.0 to 5.8) were associated with an increased risk of probable OA; a lower FEV(1) had an apparent, protective effect (RR = 0.58, 95% CI = 0.43 to 0.78). It is concluded that apprentices in animal health show a high incidence of probable OA, and that preexposure airway caliber and responsiveness as well as sensitization to pets are associated with an increased risk.

Adult↗
PubMed2001

Natural history of sensitization, symptoms and occupational diseases in apprentices exposed to laboratory animals.

The natural history of the development of sensitization and disease due to high-molecular-weight allergens is not well characterized. This study describes the time-course of the incidence of work-related symptoms, skin reactivity and occupational rhinoconjunctivitis (RC) and asthma (OA); and assesses the predictive value of skin testing and RC symptoms in apprentices exposed to laboratory animals, in a 3-4-yr programme. Four-hundred and seventeen apprentices at five institutions were assessed prospectively with questionnaire, skin-testing with animal-derived allergens, spirometry and airway responsiveness (n=373). Depending on the school, students were seen 8 (n=136), 20 (n=345), 32 (n=355) and 44 (n=98) months after starting the programme. At all visits, the incidence was greater for work-related RC symptoms followed in order by skin reactivity, occupational RC, and, almost equally, OA and work-related respiratory symptoms. The incidence-density figures were comparable for each follow-up period and for most indices up to 32 months after entry into the study and then tended to decrease. The positive predictive values (PPVs) of skin reactivity to work-related allergens for the development of work-related RC and respiratory symptoms were 30% and 9.0%, respectively, while the PPVs of work-related RC for the development of OA was 11.4%. Sensitization, symptoms and diseases occur maximally in the first 2-3 yrs after starting exposure to laboratory animals. Skin reactivity to work-related allergens and rhinoconjuctivitis symptoms have low positive predictive values.

Adolescent↗
PubMed2001

[Investigation of fetal arrhythmias by simultaneous recording of ascending aortic and superior vena caval blood flow].

In a period of 18 consecutive months, all the foetus referred to our Foetal Cardiology Unit for investigation of arrhythmia were systematically assessed by M mode echocardiography and simultaneous recording of blood flow in the superior vena cava and the aorta (SVC/Ao). This study was undertaken to compare the performance of these two approaches. The foetus were classified into three groups according to the arrhythmia diagnosed: Group 1: irregular arrhythmias, Group 2: bradycardias, Group 3: tachycardias. A surface ECG was recorded in all the neonates in whom the arrhythmias persisted. In Group 1, including 50 cases of extrasystoles (49 atrial and 1 ventricular), M mode echo and the Doppler provided the diagnosis in 42 and 47 cases respectively. This difference was not statistically significant. Group 2 comprised four cases of bradycardia (2 blocked atrial bigeminy, 2 complete atrioventricular blocks); the two methods provided the diagnosis in all 4 cases. Group 3 comprised 11 cases including 7 supraventricular tachycardias (SVT), 2 flutter, 1 chaotic atrial rhythm and 1 ectopic junctional rhythm. Complete analysis of these arrhythmias was possible by M mode in 4 cases and by Doppler in all cases. This difference was significant. The distribution of the 7 cases of SVT with respect to the duration of the ventriculoatrial interval was possible by M mode in 2 cases and in all cases by Doppler. This was a decisive factor in the choice of antiarrhythmic therapy. The authors conclude that Doppler and M mode are two echocardiographic approaches which are equally effective in the investigation of foetal atrial extrasystoles and probably of sustained foetal bradycardia. However, Doppler recording of SVC/Ao gives a more detailed and precise diagnosis of more complex foetal arrhythmias.

Aorta↗