Measuring the emission rate of an aerosol source placed in a ventilated room using a tracer gas: influence of particle wall deposition.

A method to measure the emission rate of an airborne pollutant source using a tracer gas was tested in the case of an aerosol source. The influence of particle deposition on the walls of a test room of 72 m3 was studied. The deposition rate of an aerosol of MgCl2 was determined by means of two methods: one based on measuring the aerosol concentration decay inside the ventilated room, the other based on calculation of the material mass balance. The concentration decay was monitored by optical counting and the aerosol mass concentration determined by means of sampling on a filter and analysis of the mass deposited by atomic absorption spectrometry. Four series of measurements were carried out. The curve giving the deposition rate according to the particle aerodynamic diameter (d(ae)) was established and shows deposition rates higher than those predicted using the model of Corner. The decay method gives the best results. The study carried out has shown that the phenomenon of deposition has little effect on the measurement of the aerosol source emission rate using a tracer gas for particles of aerodynamic diameter < 5 microm (underestimation < 25%). For particles of a greater diameter, wall deposition is an extremely limiting factor for the method, the influence of which can, however, be limited by using a test booth of small volume and keeping the sampling duration as short as possible.

Occupational asthma caused by chloramines in indoor swimming-pool air.

The first series of three workers who developed occupational asthma following exposure to airborne chloramines in indoor chlorinated swimming pools is reported. Health problems of swimmers in indoor pools have traditionally been attributed to the chlorine in the water. Chlorine reacts with bodily proteins to form chloramines; the most volatile and prevalent in the air above swimming pools is nitrogen trichloride. Two lifeguards and one swimming teacher with symptoms suggestive of occupational asthma kept 2-hourly measurements of peak expiratory flow at home and at work, analysed using the occupational asthma system (OASYS) plotter, and/or had specific bronchial challenge testing to nitrogen trichloride, or a workplace challenge. Air measurement in one of the pools showed the nitrogen trichloride levels to be 0.1-0.57 mg x m(-3), which was similar to other studies. Two workers had peak expiratory flow measurements showing occupational asthma (OASYS-2 scores 2.88 and 3.8), both had a positive specific challenge to nitrogen trichloride at 0.5 mg x m(-3) with negative challenges to chlorine released from sodium hypochlorite. The third worker had a positive workplace challenge. Swimming-pool asthma due to airborne nitrogen trichloride can occur in workers who do not enter the water because of this chloramine. The air above indoor swimming pools therefore needs to be assessed and managed as carefully as the water.

Exposure to chloramines in a green salad processing plant.

Acute eye and upper respiratory irritation was reported at an industrial facility that processes green salads in water containing hypochlorite. The irritant agents were chloramines resulting from the reaction of hypochlorite and nitrogen compounds coming from the sap proteins released when the vegetables were cut. Specific sampling and analytical methods were developed in order to assess the workers' exposure. Monochloramine, dichloramine and nitrogen trichloride were found in the atmosphere, which can explain the irritation phenomena of which the workers complained. In the washing room (where salads are processed), the total chloramine concentration ranged from 0.4 to 16 mg.m-3, depending on the day and the location of the area sampling points. The exposure of workers determined by personal sampling ranged from 0.2 to 5 mg.m-3. In a previous study, with swimming pool instructors exposed to the same pollutants, irritation phenomena generally appeared at chloramine values of around 0.5 mg.m-3.

Stress affects corticosteroid and immunoglobulin concentrations in male house mice (Mus musculus) and prairie voles (Microtus ochrogaster).

Glucocorticoids, secreted in response to perceived stress, can suppress immunoglobulin (Ig) levels and compromise immune function in mice and rats. Prairie voles (Microtus ochrogaster) have been reported to exhibit basal corticosterone concentrations that would cause pathological changes in the immune function of most other rodents. The goals of the present study were to verify that serum corticosterone concentrations are high in prairie voles, as compared with house mice (Mus musculus), by measuring serum corticosterone with the same RIA; to examine the effects of mild stressors on corticosterone response in both species and to examine the effects of elevated corticosterone levels on IgM and IgG levels in prairie voles and house mice. After 2 weeks of randomly timed 15-min daily restraint or cold-water swim sessions, animals were injected with sheep red blood cells. The data confirmed that basal blood concentrations of corticosterone were higher in prairie voles than house mice, but these high levels doubled after the first swim session in prairie voles, indicating that the adrenals can respond to stressors by producing increased corticosterone. After stress, antibody production (both IgM and IgG) was reduced in house mice but not in prairie voles, despite higher blood concentrations of glucocorticoids in prairie voles. Although body mass was statistically equivalent between species, prairie voles and mice differed dramatically in adrenal and splenic masses. Average adrenal mass of prairie voles was approximately three times the average mass of these organs in house mice; in contrast, the average splenic mass of house mice was approximately three times that of prairie voles. These data may be relevant to seasonal changes in immune function and survival.

Photoperiodic effects on steroid negative feedback in female prairie voles (Microtus ochrogaster).

Breeding in prairie voles is mainly restricted to the autumn and winter of most years. The organization of estrus in female prairie voles is unusual because behavioral estrus is induced by chemosensory stimuli from the urine of adult conspecific males. Isolated females exhibit undetectable levels of estradiol and never display estrous behavior, yet exposure to male urine causes a cascade of endocrine changes that evoke estrogen secretion from the ovaries and estrous behavior within 24 hr. In the prairie vole, the extreme dependence of estrus on chemosensory stimuli raises the possibility that their ovaries may be less prominent in the regulation of gonadotropin secretion than in species with more endogenously organized estrous cycles. The present study examined the contribution of the ovaries in luteinizing hormone (LH) regulation in prairie voles. Females were maintained for 9 weeks in either long (LD 16:8) or short (LD 8:16) photoperiodic conditions, a blood sample was obtained, and then animals were either ovariectomized or received a sham procedure. Another blood sample was obtained a week later and assayed for serum LH. Blood serum LH levels were significantly reduced in short-day voles, compared to long-day animals. After ovariectomy both long-day and short-day voles exhibited equivalent elevations in LH levels. This study provides evidence that photoperiod is measured in female voles and the ovaries appear to produce sufficient steroids to suppress LH release.

Day length affects immune cell numbers in deer mice: interactions with age, sex, and prenatal photoperiod.

The extent to which day length affects immune function was examined in the present study. Three goals were pursued: 1) to confirm and extend the observation that the immune systems of adult deer mice (Peromyscus maniculatus) are responsive to changes in photoperiod, 2) to examine the development of the photoperiod-associated changes in immune function, and 3) to discover whether photoperiodic information transmitted to the young during gestation influences immune function. In experiment 1, adult mice housed in short days had higher white blood cell and lymphocyte numbers than their long-day cohorts. Red blood cell and differential cell counts did not differ between long- and short-day animals. No sex differences were observed in the pattern of immune responses to photoperiod. The effect of photoperiod on immune cells in prepubertal animals was examined in experiment 2; a similar pattern of results was obtained as that for experiment 1, suggesting that the photoperiodic effect on the immune system is not mediated by sex steroid hormones. Prenatal and postnatal photoperiodic effects on immune cells were examined in experiment 3; pups gestated in one day length were cross-fostered to mothers in the same day length conditions or to mothers maintained in the alternative day length. The results of experiment 3 suggested that photoperiodic information transmitted from the mother to the young in utero subsequently affected immune systems of the pups. Animals gestated in short day lengths displayed higher immune status throughout life than mice gestated in long days. These results are discussed from an adaptive functional perspective.

Conservative treatment of calcific trochanteric bursitis.

OBJECTIVE: To present a case of conservatively managed calcific trochanteric bursitis and discuss differential diagnosis and treatment alternatives. CLINICAL FEATURES: A 53-yr-old obese female presented with acute severe lateral hip and posterolateral thigh pain. Examination findings were consistent with trochanteric bursitis and radiographs demonstrated calcific infiltration of the trochanteric bursa. INTERVENTION AND OUTCOME: An intensive 2-wk course of pulsed ultrasound, ice massage, interferential current and chiropractic lumbopelvic manipulation resulted in symptomatic relief, abolishment of palpatory tenderness and return of pain-free passive and resisted range of motion of the hip. CONCLUSIONS: Trochanteric bursitis is a common cause of hip pain. A trial of conservative measures is warranted for this condition, even when calcinosis is present, before more invasive therapies are considered.

Exposure to metallic catalyst dust: manufacturing and handling of catalysts in the chemical industry.

The exposure of workers to metallic catalyst dust was assessed in manufacturing and reprocessing industries, and during catalyst handling in the chemical industry. The level of exposure was found to be generally low during the manufacturing and reprocessing activities taking place in permanent installations, and extremely variable during catalyst handling performed by workers of sub-contracting specialized firms. The difficulties in treating the occupational hygiene problems of these workers are pointed out.

Exposure to sulphuric acid and sulphur dioxide in the manufacturing of titanium dioxide.

An assessment of exposure to sulphuric acid and sulphur dioxide was performed in the French titanium dioxide manufacturing industry. The three plants use the sulphuric acid process, with potential exposure mainly to sulphur dioxide and sulphuric acid. The exposures found were below the French limit values, except for some employees using the Moore filtration process in one plant. For sulphuric acid sampling, a comparison was made between thoracic particulate mass and inhalable particulate mass, from samples taken with a Marple cascade impactor. This comparison shows that the suggested new limit value (0.1 mg m-3 in thoracic particulate mass) would be much more severe than the present one (1.0 mg m-3 with no restriction as to the droplet size).

Calcification of vas deferens associated with diabetes mellitus.

Calcification of the vas deferens may be associated with diabetes mellitus. This paper discusses the case of a patient in which this occurred. In clinical practice, this radiological finding may indicate further diagnostic workup for diabetes or other causative conditions which are described here.