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PubMed1987

Bioaerosols and office building ventilation systems.

Becterial and fungal spore samples were collected from twelve office building ventilation systems. Measurements were done both with and without humidification. Ventilation or humidification systems were not found to act as bioaerosol sources in any case. No difference was observed between bioaerosol counts in offices with and without humidification. The microbial levels decreased in all ventilation systems.

Climate↗
PubMed1987

Radon and its decay products in the indoor environment: radiation exposure and risk estimation.

Radon, a member of the uranium decay chains, enters the indoor environment from the building subsoil, walls and the drinking water. In areas with high radium content of rocks and soil, considerable indoor levels of radon are measured. A sample of 32 conventional homes in Southeastern Switzerland, an area with generally high uranium concentrations in the subsoil, showed an arithmetic mean radon concentration in living quarters and cellars of 307 Bq/m3 (8.3 pCi/l) and 1410 Bq/m3 (38.1 pCi/l), respectively. Using UNSCEAR82 conversion factors, the annual effective dose equivalent in this area amounts to 9 mSv (900 mrem). The corresponding dose to the stem cells of the tracheobronchial tissue is about 100 mSv/a (10 rem/a). Life time exposure in such dwellings is in the range of occupational doses collected in modern uranium mines and leading to a significant increase in the lung cancer risk.

Air Pollutants↗
PubMed1989

Fungal air-borne spores as health risk factors among workers in alimentary industries.

A survey to evaluate the occurrence of air-borne fungal spores in two different food industries, dairies and bakeries, was conducted. Our data revealed considerable fungal pollution in the environments of both industries, as well as some differences in the distribution of the genera of fungi recovered. Noteworthy was the frequent finding of numerous fungi frequently responsible for allergic rhinitis, asthma and other diseases, or well-known for their production of mycotoxins in foods or characterized by their degradative activity against various substances. Aspergillus, Candida, Fusarium, Geotrichum, Mucor and Penicillium were the most common genera identified in dairies while Alternaria, Aspergillus, Botrytis, Candida, Cladosporium, Penicillium and Saccharomyces occurred more frequently in bakeries. The survey showed that fungi can play a significant role in allergic and non-allergic diseases in modern working environments.

Air Microbiology↗
PubMed1987

Allometric relations of total volumes of prolactin cells and corticotropic cells to body length in the annual cyprinodont Cynolebias whitei: effects of environmental salinity, stress and ageing.

An analysis of the allometric relations of the total volumes occupied by prolactin (PRL) and corticotropic (ACTH) cells (PRL volume and ACTH volume, respectively) to body length and a study of the immunocytochemical staining intensity of PRL and ACTH cells were used to determine the differences in activity of PRL and ACTH cells in freshwater-reared and in saltwater-reared Cynolebias whitei during the entire lifespan of this annual cyprinodont fish. An inflection in the allometric relation of PRL volume to body length was observed in fish of one-week old. The relatively large PRL volume in younger fish may be related to PRL cell activity before hatching. No inflections were observed in the allometric relations of PRL volume and ACTH volume to body length at the onset of maturation and the onset of ageing, indicating that the increased pituitary growth in maturing and ageing C. whitei is not the result of changes in PRL or ACTH cells. The slope of the allometric relation of PRL volume to body length in freshwater-reared fish was significantly steeper than the slope in saltwater-reared fish. The PRL volume in adult freshwater-reared fish was eight times larger than that in saltwater-reared fish of the same length. The intensity of immunocytochemical staining of saltwater PRL cells was significantly reduced. These volumetric and staining differences correspond to the low functional demand put upon PRL cells in saltwater-adapted fish. In contrast, the slope of the allometric relation of ACTH volume to body length and the intensity of immunocytochemical staining of ACTH cells were similar in freshwater-reared and in saltwater-reared fish.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1984

The effect of water acidification on prolactin cells and pars intermedia PAS-positive cells in the teleost fish Oreochromis (formerly Sarotherodon) mossambicus and Carassius auratus.

Although exposure to acid water (pH 3.5) induces severe and prolonged reduction in plasma osmolarity and total plasma calcium concentration in tilapia (Oreochromis mossambicus) and goldfish (Carassius auratus), the responses of the hypophyseal cells are clearly different. In tilapia, the size of the rostral pars distalis of the pituitary gland is enlarged as a result of the increase in size and number of prolactin cells. The pars intermedia PAS-positive (PIPAS) cells are not noticeably changed. Conversely, in goldfish, prolactin cells are unaffected, whereas the number of enlarged PIPAS cells increases markedly. Stimulation of prolactin secretion may be responsible for the partial restoration of plasma osmolarity and calcium levels observed in tilapia after two weeks exposure to acid water. Prolactin cells apparently play a role in the adaptation to acid stress by counteracting osmoregulatory disturbances. Goldfish show no restoration of plasma osmolarity during the course of the experiment. Plasma calcium levels tend to increase. Although prolactin may have an osmoregulatory function in goldfish under steady state conditions, goldfish prolactin cells do not seem to participate in the physiological adaptation to environmental changes that disturb water and ion homeostasis. The function of PIPAS cells in tilapia remains unclear and is apparently unconnected with ion regulation. The observations on these cells in goldfish are consistent with the hypercalcemic activity suggested for them.

Animals↗
PubMed1981

Evidence for a direct role of alpha-MSH in morphological background adaptation of the skin in Sarotherodon mossambicus.

The skin colour of the cichlid teleost Sarotherodon mossambicus adapted rapidly to changes in background colour. The physiological adaptation was associated with morphological changes in the dermis. Differences in the dermis were found between fish adapted to a black or white background for 14 days. Number and size of the melanophores as well as the amount of pigment in the cytoplasm of the melanophores were significantly increased in fish adapted to a black background. Changes in the dermis parallelled changes in the state of activity of the two endocrine cell types in the pars intermedia of the pituitary. Both the PAS positive cells and the MSH producing cells were more active when the fish were exposed to a black rather than a white background. Fish continuously infused with alpha-MSH, using an osmotic minipump, had more melanophore cytoplasm and pigment per dermis surface unit area than untreated fish. The activity of the MSH cells in MSH-infused fish exposed to a black background was reduced to a level comparable to the MSH cell activity of untreated fish on a white background. alpha-MSH treated fish that were exposed to a white background had many disintegrating MSH cells. These findings point to inactivation of these cells by exogenous alpha-MSH. The activity of the PAS positive cells was not influenced by treatment with alpha-MSH.

Acclimatization↗
PubMed1993

Long-term sensitization and environmental conditioning in terrestrial snails.

The hypothesis that a long-term increase of behavioural responses in snails (over a period of days) might be due to environmental conditioning was examined. Training consisted of delivering electric shocks non-contingently with test stimuli twice per day for 5 days to freely moving snails on a ball floating in water. After training, a significant difference in amplitude of a withdrawal reaction to tactile test stimulation appeared between shocked and control snails. Responses were significantly facilitated in shocked animals for up to 12 days after training, but only if the animals were tested in the environment used for training. Testing of the same groups of animals crawling freely on the glass lid of a tank in which they lived between experimental sessions revealed no difference in responses to the same stimuli between shocked and control snails. Injection of the neurotoxin 5,7-dihydroxytryptamine, which selectively impairs serotonergic cells, eliminated the differences between shocked and control animals. Changing the pH of the water in which the ball floated, by addition of citric acid, led to a significant selective increase of responsiveness in snails sensitized in this environment relative to the responsiveness of the same snails with normal water in the tank. The results suggest that the long-term sensitization of withdrawal reactions observed is at least in part a manifestation of an associative process, namely environmental conditioning.

5,7-Dihydroxytryptamine↗
PubMed1982

A protease as a possible sensor of environmental conditions in E. coli outer membrane.

A mutant strain devoid of the colicin A protease activity (cpr) located at the external face of the outer membrane has been isolated. The location of the mutation (about 74 min on the genetic map), its pleiotropic effects concerning mainly the protein composition of the outer membrane and sensitivity to phages and colicins, are very similar in cpr and in tpo, envZ, perA strains that are affected in the ompB locus. Conditions resulting in inhibition of the colicin A protease activity also result in transcriptional regulation of OmpF, OmpC, and LamB protein synthesis. The possibility for this protease as an osmosensor of the cell's external environment is discussed.

Cell Membrane↗
PubMed1987

Hydroxyproline excretion in schoolchildren and its relationship to measures of indoor air pollution.

The urinary hydroxyproline excretion was investigated in a population of 6- to 9-year-old schoolchildren living in the Netherlands. Early morning samples of urine were collected at the end of a week in which personal and home monitoring for nitrogen dioxide (NO2) was carried out, and in which detailed information on gas appliances and on parental smoking habits was gathered. In addition, the pulmonary function of the children was measured, and their respiratory symptoms were collected using a standardized questionnaire which was completed by the parents. The hydroxyproline concentrations were standardized for urinary creatinine content. The hydroxyproline/creatinine ratio (HOP/C ratio) was found to be unrelated to NO2 exposure. The presence of major NO2-sources in the kitchen, vented and unvented gas-fired waterheaters, was significantly associated with elevated HOP/C ratios, due to a negative relationship with the creatinine concentration. There was a tendency for HOP/C to increase with the amount of tobacco smoked in the presence of a child. Respiratory symptoms and pulmonary function were unrelated to HOP/C. In this population, the urinary HOP/C ratio was not found to be a close correlate of exposure to NO2 or tobacco smoke, and of respiratory symptoms and pulmonary function.

Air Pollutants↗
PubMed1985

Urinary cobalt as a measure of exposure in the hard metal industry.

Twenty-six workers in a hard metal manufacturing plant were monitored by cobalt urinary and ambient air measurements during the first month after summer holidays. Cobalt determinations were performed utilizing AAS, with a preliminary chelation and extraction procedure for urinary samples. Almost all personal ambient air samples turned out to be under the cobalt dust TLV of 0.1 mg/m3. When restarting work after the holidays, urinary values did not differ from the control group. At the end of the first working week, urinary cobalt had increased four fold, then decreased to the original values on the following Monday before restarting work. Thereafter, the weekend was no longer sufficient to reduce the levels to normal urinary cobalt values. The values rose to the same level observed before the holidays, and dit not substantially decrease even after the weekend. End-shift urinary cobalt values showed a good relationship with present as well as with mean past exposure on the first and the fifth weekday, but the third day did not. The correlation was better with present exposure on Monday and with mean past exposure on Friday. The observed differences may be explained by the minor influence of recent exposure on present exposure on Monday. The highest values were found on Wednesday. We suggest the utilization of end-shift urinary cobalt determination as a measure of the present exposure on Monday, and of mean recent or preceding exposure on Friday.

Air Pollutants, Occupational↗
PubMed1985

Effects of ambient temperature and altitude on ventilation and gas exchange in deer mice (Peromyscus maniculatus).

The effects of different ambient temperatures (Ta) on gas exchange and ventilation in deer mice (Peromyscus maniculatus) were determined after acclimation to low and high altitude (340 and 3,800 m). At both low and high altitude, oxygen consumption (VO2) decreased with increasing Ta at Ta from -10 to 30 degrees C. The VO2 was 15-20% smaller at high altitude than at low altitude at Ta below 30 degrees C. Increased VO2 at Ta below thermoneutrality was supported by increased minute volume (VI) at both low and high altitude. At most Ta, the change in VI was primarily a function of changing respiration frequency (f); relatively little change occurred in tidal volume (VT) or oxygen extraction efficiency (O2EE). At Ta = 0 degree C and below at high altitude, VI was constant due to declining VT and O2EE increased in order to maintain high VO2. At high altitude, VI (BTP) was 30-40% higher at a given Ta than at low altitude, except at Ta below 10 degrees C. The increased VI at high altitude was due primarily to a proportional increase in f, which attained mean values of 450-500 breaths/min at Ta below 0 degree C. The VI (STP) was equivalent at high and low altitude at Ta of 10 degrees C and above. At lower Ta, VI (STPD) was larger at low altitude. At both altitudes, respiratory heat loss was a small fraction (less than 10%) of metabolic heat production, except at high Ta (20-30 degrees C).

Acclimatization↗
PubMed1986

Subjective comfort vote and air temperature as predictors of performance in factory workers.

Volunteer factory workers performed a series of tests in a mobile climate laboratory. The tests simulated factory skills and were performed at 6 degrees, 12 degrees, 18 degrees or 24 degrees C at low vapour pressures. At each temperature four groups of about 30 workers were tested: black men, and women and white men and women. A first order polynomial was used to fit the data for temperature and comfort vote. The comfort vote predicted about 6% of performance, temperature about 11%. On some manual tasks air temperature predicted more than 40% of performance. There were few differences between the groups.

Climate↗