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M Francis

Publications and source records attributed to M Francis.

At least 37 records · Page 2Linked to original sources
PubMed1998

Aggregate exposures under the Food Quality Protection Act: An approach using chlorpyrifos.

The Food Quality Protection Act of 1996 (Public Law 104-170, August 3, 1996), which amended the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Federal Food, Drug, and Cosmetic Act (FFDCA), requires that the EPA evaluate pesticide safety in light of potential aggregate exposures from both nondietary and dietary routes. As with any new legislation, there has been considerable discussion and challenges presented within the regulatory and scientific communities regarding the effective implementation of this act as it relates to the determination of aggregate exposures. This paper describes a novel methodology incorporating personal exposure factors, route-specific exposure measurements, and usage information to characterize potential aggregate exposures to a widely used pesticide, chlorpyrifos. A calendar model framework has been developed to describe potential multipathway exposures to individuals. The model assimilates information regarding the typical use patterns of chlorpyrifos-containing pesticides in concert with quantitative exposure and dose measurements to estimate the probability and magnitude of exposures to members of the U.S. population. Studies measuring 3,5,6-trichloropyridinol, the primary metabolite of chlorpyrifos, in the urine of individuals within the United States show that aggregate exposures derived from this approach are consistent with actual population-based exposures to chlorpyrifos. According to this assessment, potential health risks attributed to exposure to chlorpyrifos are low when compared to relevant toxicological end points.

Animals↗
PubMed1998

Evaluation of a population with occupational exposure to airborne ammonium perchlorate for possible acute or chronic effects on thyroid function.

Employees at an ammonium perchlorate production facility in Nevada and a larger control population from the same chemical complex without direct AP exposure were monitored extensively for airborne perchlorate exposure. Single-shift and working-lifetime cumulative dose estimates were made using standard breathing-rate estimates and assuming rapid absorption, based upon solubility. Calculated single-shift doses ranged from 0.2 to 436 micrograms/kg, with an average of 36 micrograms/kg. Working-lifetime cumulative doses in the higher exposure group ranged from 8,000 to 88,000 micrograms/kg, with an average of 38,000 micrograms/kg. Thyroid profiles, including free thyroxine index and thyroid-stimulating hormone level, were obtained both before shift and after shift to assess thyroid-axis perturbation due to single working-shift perchlorate exposure. Thyroid-function data were also analyzed with respect to estimates of cumulative exposure to assess any measurable chronic effects on thyroid gland function. Additionally, standard clinical blood test parameters of liver, kidney, and bone marrow function were evaluated to assess any measurable chronic effects of perchlorate exposure on those organs. Multiple regression was used to assess the effects of exposure variables and demographic variables on organ function parameters. No perchlorate-attributable effects on thyroid, bone marrow, kidney, or liver function were detected.

Acute Disease↗
PubMed1997

Lymphohematopoietic cancers and butadiene and styrene exposure in synthetic rubber manufacture.

The described nested case-control study of lymphohematopoietic cancers occurring in a cohort of synthetic rubber production workers was conducted to determine the associations of these cancers with exposure to butadiene and styrene. Cases have been confirmed through hospital record review of 95 percent of the cancers. Exposures are based on measured values of the two chemicals from personal monitoring data in seven of the eight plants under study. The results indicate that the risk of leukemia increases with exposure to a time-weighted average butadiene measure. The odds ratio at only 1 ppm average butadiene exposure is 1.50 (95% CI 1.07, 2.10). Work in specific areas also contributes to the risk, possibly because these areas have not been completely characterized for differences in butadiene exposure. Hodgkins disease is also associated with butadiene exposure. Multiple myeloma, lymphosarcoma, and all lymphomas are associated with exposure to styrene. Since workers in this industry are apparently exposed to two carcinogenic agents, further effort must be made to distinguish the exposures to each chemical over time and to characterize their interrelationship with the risk of cancers of the lymphohematopoietic system.

Butadienes↗
PubMed1997

A human homologue of the Drosophila eyes absent gene underlies branchio-oto-renal (BOR) syndrome and identifies a novel gene family.

A candidate gene for Branchio-Oto-Renal (BOR) syndrome was identified at chromosome 8q13.3 by positional cloning and shown to underlie the disease. This gene is a human homologue of the Drosophila eyes absent gene (eya), and was therefore called EYA1. A highly conserved 271-amino acid C-terminal region was also found in the products of two other human genes (EYA2 and EYA3), demonstrating the existence of a novel gene family. The expression pattern of the murine EYA1 orthologue, Eya1, suggests a role in the development of all components of the inner ear, from the emergence of the otic placode. In the developing kidney, the expression pattern is indicative of a role for Eya1 in the metanephric cells surrounding the 'just-divided' ureteric branches.

Adult↗
PubMed1997

Abnormal audiograms and elevated acoustic reflex thresholds in obligate carriers of autosomal recessive non-syndromic hearing loss.

Pure-tone audiograms and acoustic reflex thresholds were obtained in 24 presumed obligate carriers of autosomal recessive non-syndromic hearing loss and 30 sex and age appropriate control subjects, with a view to evaluating the prevalence of abnormalities on these tests in the two groups, and a possible link between the findings on the two tests, which may help to localize threshold deficits and/or abnormal configurations to different sections of the reflex arc. Six (25%) of the carriers and one control subject had abnormal audiograms, inferred to be of genetic aetiology through careful exclusion of environmental risk factors. Four additional carriers had acoustic reflex threshold abnormalities. None of the carriers had an abnormality on both tests. The audiometric configurations and acoustic reflex patterns of abnormality were diverse, and may be a reflection of the genetic heterogeneity in ARNSHL.

Adult↗
PubMed1996

Comparative profile of novel potent bradykinin antagonists at human B1 and B2 receptors.

We have undertaken a comparative pharmacological profile of novel bradykinin antagonists on human B1 and B2 receptor binding and functional assays. We found that there was an excellent correlation between binding and functional data for the compounds at the B1 receptor. In general, although there was a good correlation between the binding and functional data at the B2 receptor there was a greater degree of scatter in the correlation, particularly with compounds that possessed both B1 and B2 binding and antagonist activity. Of the compounds that were highly selective for the B2 receptor, CP-0597 had high binding activity but showed an unexpectedly low functional potency in the human ileum. The reason for this discrepancy is unclear. In general we found that binding activity with both the B1 and B2 antagonist compounds correlated well with their functional activity.

Adult↗
PubMed1996

Reported blood exposure rates and staff nurse satisfaction with a closed surgical drainage system.

BACKGROUND: The purposes of this investigation were (1) to describe performance characteristics, incidence of exposure, and staff satisfaction with a closed drainage system, the Kendall Tru-Close, and (2) to compare performance, incidence of exposure, and satisfaction between the closed drainage system and a currently used surgical drainage system (the Hemovac). METHODS: Subjects were 40 adult male and female patients who had undergone selective orthopedic joint surgery. Twenty patients received the Hemovac drainage system, and 20 patients received the Tru-Close drainage system. Data collection instruments included a patient demographic data form, a daily assessment form, a nurses' bedside survey (self-report), and a satisfaction questionnaire. RESULTS: There were significantly fewer exposures with the closed drainage system when compared with the Hemovac system. An odds ratio of 5.09 indicated that the odds of exposure to fluids with the Hemovac system were five times greater than for the closed system. Nursing satisfaction scores were higher for the Tru-Close system than the Hemovac system for items that related to protection from exposure to self or environment. However, overall nursing satisfaction with the new device was mixed. CONCLUSIONS: Although nurses liked the increased protection from exposure afforded by the Tru-Close drainage system, other patient management issues emerged related to the increased weight of the reservoir bag.

Adult↗
PubMed1996

Immunoglobulin-A and the pathogenesis of schistosomal glomerulopathy.

Several observations suggest that the evolution of schistosomal glomerulopathy into clinically overt and progressive disease may involve pathogenetic mechanisms other than simple glomerular deposition of parasitic antigens. In a previous study, IgA was suggested to be a mediator of late glomerular lesions in this disease. This issue is further addressed in this work. The study includes 32 patients with hepatosplenic schistosomiasis, of whom 16 had overt glomerular involvement, along with four control groups: (a) 15 healthy volunteers; (b) 15 patients with simple intestinal mansoniasis; (c) 17 patients with non-schistosomal chronic liver disease; and (d) 21 subjects with primary nephrotic syndrome not associated with schistosomiasis. Routine assessment was done for all subjects including confirmatory tests for schistosomal infection, liver and renal function tests, hepatitis viral markers and abdominal ultrasonography. The total serum concentrations of IgG, IgM, IgA were measured, as well as their respective circulating immune complexes, rheumatoid factors, anti-gliadin- and anti-DNA-antibodies. Liver and renal biopsies were obtained from the relevant groups and studied by light microscopy. Renal biopsies were also examined by immunofluorescence. Patients with simple intestinal schistosomiasis had a significant increase in IgM antigliadin antibodies. Those complicated with hepatosplenic involvement also had a significant increase in the mean IgG anti-gliadin antibodies, IgG rheumatoid factor and IgM anti-DNA activity. Cases further complicated by overt glomerular disease showed a distinct IgA predominance, mainly expressed in the serum anti-gliadin antibody pool and anti-DNA activity. This profile was essentially similar to that observed in control cirrhotics. There was a significant increase in the frequency of IgA glomerular deposits in renal biopsies obtained from patients with overt schistosomal glomerulopathy, in contrast to control nephrotics. The deposits were mainly mesangial, but were also encountered in subendothelial, subepithelial and peritubular locations. Their frequency was significantly higher with more advanced lesions as seen by light microscopy. The relevance of these data is discussed, leading to the following conclusions: (a) serum IgA-anti-gliadin and -anti-DNA antibodies, and glomerular IgA deposits are markers of significant renal involvement in patients with hepatosplenic schistosomiasis. (b) IgA may be involved in the pathogenesis of advanced glomerular pathology when superimposed on parasite-induced lesions. (c) There is a significant increase in serum auto-reactivity in hepatosplenic schistosomiasis, which may also have pathogentic implications. (d) Increased production by the inflammatory bowel lesions, impaired clearance by the fibrotic livers and probable switching of immunoglobulin synthesis are suggested to explain the observed IgA predominance in those who develop renal complications.

Adolescent↗
PubMed1996

Dips on Békésy or audioscan fail to identify carriers of autosomal recessive non-syndromic hearing loss.

Békésy and audioscan sweep audiometry tests were carried out in 24 presumed obligate carriers of autosomal recessive non-syndromic hearing loss and 30 sex and age appropriate controls, with a view to defining the most expedient criteria for dips on either test in respect of possible carrier detection. On Békésy, dips with a minimum depth of 22.5 dB generated the greatest difference between carriers and non-carriers, while on audioscan, the criterion of a minimum dip depth of 15 dB provided the best discriminant. Using these criteria, the prevalence of dips was also evaluated in 8 unaffected siblings and 24 age appropriate control subjects. The findings both in the adult and the paediatric groups do not support the hypothesis that the presence of dips, either on Békésy or audioscan, is linked to the carrier state in ARNSHL.

Acoustic Impedance Tests↗
PubMed1996

Quantification of historical exposures in occupational cohort studies.

Relatively few investigators have estimated quantitative exposure levels in epidemiologic studies, and, for those that have, few have discussed the strengths and weakness of their estimation method with respect to other methods. This paper reviews the steps for developing quantitative exposure estimates that have been used in published studies. First, the qualitative considerations to be evaluated in the selection of the agent to be estimated (i.e., the disease mechanism, the effects of exposure mixtures and interactions, the physical state of the agent, and the routes of exposures) are discussed. Considerations for developing exposure groups are then presented, including work history and exposure information characteristics, the homogeneity of exposures within exposure groups, the exposure estimation method, and the disease risk analyses to be performed. The various exposure estimation approaches are reviewed for their strengths and weaknesses, including the calculation of the mean exposures from existing exposure measurements, statistical models, measurement data from surrogate exposures, and professional judgment. Recommendations for future studies are provided.

Cohort Studies↗
PubMed1995

Phenotypic manifestations of branchio-oto-renal syndrome.

Branchiootorenal (BOR) syndrome is a variable, autosomal-dominant disorder of the first and second embryonic branchial arches, kidneys, and urinary tract. We describe the phenotype in 45 individuals, highlighting differences and similarities reported in other studies. Characteristic temporal bone findings include cochlear hypoplasia (4/5 of normal size with only 2 turns), dilation of the vestibular aqueduct, bulbous internal auditory canals, deep posterior fossae, and acutely-angled promontories.

Abnormalities, Multiple↗
PubMed1995

[Epidemiology of Helicobacter pylori infection in Hungary (comparative sero-epidemiologic study)].

In the last decade pathogenetical role of Helicobacter pylori infection has been proved in development of gastroduodenal alterations. DNA-RNA hybridisation and protein profile studies proved that Helicobacter pylori is an organism distinct from other bacteria. Therefore serology became a useful method to study the epidemiology of Helicobacter pylori infection in various populations. In Hungary sera were collected from adults aged 20-60 in blood banks (Military Hospital, Tolna County Hospital) in 1993. The samples were classified in 5 year increment groups and questionnaires were filled out. Anti-H. pylori IgG were tested using Cobas Core kit (Roche Diagnostic). The overall rate of seropositivity was 63.3%. The prevalence according to age was the following: 20-24 yrs = 44%, 25-29 yrs = 40%, 30-34 yrs = 52%, 35-39 yrs = 64%, 40-44 yrs = 75%, 45-49 yrs = 73%, 50-54 yrs = 77%, 55-59 yrs = 83%. There were no statistical difference between gender, living in urban or rural areas at the time of collection or in childhood, between the level of education, type of labour or social status. However we found statistical correlation between anti-H. pylori seropositivity and epigastric symptoms. The same characteristics of Helicobacter pylori infection were found in Hungary as well as in other countries. In groups between 20 and 30 years has been proved lower prevalence in Hungary than in Poland, Bulgaria.

Adult↗
PubMed1995

Acute exposure to acid fog: influence of breathing pattern on effective dose.

Concern about the possible adverse health effects of acid fog has been fed by two observations: air pollution disasters earlier in this century were typically associated with fog, and current samples of fog water can be strongly acid. To study the acute effects of acid fog on the lung, the authors generated a monodisperse 10 microM MMAD aerosol of H2SO4 with a pH of 2.0 and a nominal concentration of 500 micrograms/m3. They exposed seven healthy young men on alternate days to acid or control equiosmolar NaCl aerosol during 40 min of resting ventilation and 20 min of exercise; the latter was sufficiently intense to induce oronasal breathing. Exposure was by means of a head dome, a head-only exposure device that permitted continuous measurement (unfettered breathing) of Vr, f, VE, and the onset and persistence of oronasal breathing. In this article the authors compare the relative importance of parameters contributing to the between-subject variability in estimated hydrogen ion dose to the lower airways (H+LAW), based on analysis of variance. Physiologic parameters accounted for 70% of the variability, of which 34% was due to differences in duration of oronasal breathing (tON) and 36% to differences in ventilation rate during oronasal breathing (VE(ON)); inhaled hydrogen ion concentration [H+], the environmental parameter, contributed only 30%. Minute ventilation at the time of transition from nasal to oronasal breathing varied significantly among subjects even if normalized to FVC, an index of lung size.

Acid Rain↗
PubMed1995

A pilot study of alcohol and drug-related traffic accidents and death in two Jamaican parishes, 1991.

This study is a preliminary effort to document the role of drugs in motor vehicle accidents as it examines the presence of alcohol, marijuana and cocaine in blood samples of thirty-one motor vehicle fatalities. The study identified that males (90.3%) and pedestrians (41.9%) were killed most often. Evidence of alcohol intake was found in 77.5% of the fatalities and 35.5% had alcohol levels above the legal acceptable limits. Traces of marijuana were found in 22.5% and a combination of alcohol and marijuana in 22.5% of the victims.

Accidents, Traffic↗
PubMed1994

60 Hertz magnetic field exposure assessment for an investigation of leukemia in telephone lineworkers.

The purpose of this paper is to present the assessment of magnetic field exposure conducted as a part of a nested case-control investigation of leukemia mortality in telephone lineworkers. For the purposes of exposure classification, telephone company jobs were initially divided into two classes: those with potential for working in an electric environment, referred to as linework jobs, and those not working in an electric environment, referred to as nonlinework jobs. Linework jobs were further divided into the following four categories: outside plant technicians (OPT), installation/maintenance/repair (IMR) technicians, central office technicians (COT), and cable splicing technicians (CST). These job groupings were based on similarity of work tasks and exposure environments. Emdex data-logging dosimeters were used to measure personal exposures to ELF magnetic fields for 204 telephone company workers. Three general classes of exposure indices were calculated for each exposure record: measures of central tendency, measures of peak or maximum exposure, and measures of exposure variability. CSTs had the highest full-shift mean and median exposure, 4.3 and 3.2 mG, respectively. CSTs also ranked the highest, with average peak, average 95th percentile, and average time above background equal to 99.2 mG, 11.1 mG, and 156 min, respectively. In addition, the results suggest the OPT and IMR technicians have exposures similar to nonlineworkers. Exposure classifications, therefore, which misclassify all lineworkers into one "telephone lineworker" job grouping are not appropriate and future studies should concentrate on cable splicing technicians.

Case-Control Studies↗
PubMed1994

Screening for consumptive coagulopathy in preeclampsia.

OBJECTIVE: To identify a practical and cost-effective profile of tests to screen for consumptive coagulopathy in preeclampsia (PE). METHODS: Retrospective analysis of the results of measurements of platelet count, prothrombin time (PT), activated partial thromboplastin time (APTT), plasma fibrinogen and D-dimers in 100 patients presenting with PE uncomplicated by other disease or antepartum hemorrhage. Twenty-four patients had pregnancy-induced hypertension only, and 76 hypertension with proteinuria. RESULTS: The incidence of abnormal tests on presentation was raised D-dimers 34%, thrombocytopenia 14%, prolonged APTT 12%, prolonged PT 3%, and low fibrinogen 2%. Prolonged APTT without thrombocytopenia occurred in 8% of patients. In 19 patients with elevation of D-dimers alone, only one showed evidence of consumption of coagulation factors on subsequent testing. CONCLUSIONS: A combination of platelet count and APTT is probably a practical and cost-effective combination to screen for consumptive coagulopathy in PE.

Adult↗
PubMed1993

Effects of low dose transdermal scopolamine on heart rate variability in acute myocardial infarction.

OBJECTIVES: We hypothesized that by enhancing parasympathetic activity, low dose transdermal scopolamine would increase heart rate variability after myocardial infarction. BACKGROUND: Low heart rate variability is associated with increased mortality after acute myocardial infarction. METHODS: Conventional time domain heart rate variability was measured from 24-h Holter recordings of 61 consecutive male patients (mean age 58 +/- 10 years, left ventricular ejection fraction 44.7 +/- 15.5%) 6 days (median) after acute myocardial infarction. Patients were then randomly assigned to wear one patch of transdermal scopolamine or a matching placebo patch for 24 h, during which their 24-h heart rate variability was remeasured. RESULTS: Compared with placebo, transdermal scopolamine caused a significant increase in time domain measures of 24-h heart rate variability by 26% to 35% above baseline. Transdermal scopolamine was well tolerated. CONCLUSIONS: Low dose transdermal scopolamine safely increases cardiac parasympathetic activity and short-term heart rate variability after acute myocardial infarction. Whether the effect of transdermal scopolamine on heart rate variability is a reasonable surrogate for improvement of long-term morbidity and mortality requires an appropriate designed investigation.

Administration, Cutaneous↗