Performance of a high-volume cascade impactor in six European urban environments: mass measurement and chemical characterization of size-segregated particulate samples.

The performance of a modified Harvard high-volume cascade impactor (HVCI) was evaluated in six field campaigns with size-segregated particulate samplings for chemical and toxicological characterization. The 7-week sampling campaigns in 2002-2003 in Duisburg (autumn), Prague (winter), Amsterdam (winter), Helsinki (spring), Barcelona (spring), and Athens (summer) were selected to represent contrasting urban environments and seasons of public health interest due to high particulate concentrations or previous findings in epidemiological studies. Particulate samples were collected in parallel with the HVCI (PM(10-2.5), PM(2.5-1), PM(1-0.2), PM(0.2)), a virtual impactor (VI; PM(10-2.5), PM(2.5)), and a Berner low-pressure impactor (BLPI; 10 stages between 0.035 and 10 mum in particle diameter) using a 3- or 4-day sampling duration. The campaigns exhibited different profiles with regard to particulate mass concentration, size distribution, chemical composition and meteorological conditions, thus providing a demanding setup for an overall field comparison of the HVCI with the VI and BLPI reference samplers. Size-segregated particulate mass concentration could be reasonably well measured with the present HVCI configuration. The coarse (PM(10-2.5)) and fine (PM(2.5)) particulate mass agreed within 10% with the low-volume reference samplers, and the four-stage size distribution of the HVCI followed the modal pattern of urban aerosol. The concentrations of chemical constituents measured and integrated especially for the HVCI-PM(2.5) differed to some extent from those measured from the corresponding VI-PM(2.5) samples. This implies that when investigating the association of toxicological responses with the chemical constituents of particulate matter, it is necessary to use the chemical composition data of the same samples as used in toxicological experiments.

Mortality during winter smog episodes 1982, 1985, 1987 and 1993 in the Czech Republic.

OBJECTIVES: Severe air pollution episodes were recorded during the 1980s and early 1990s in the Czech Republic as a result of widespread combustion of brown coal. A population-based retrospective study investigated the relationship between air pollution and daily mortality in six highly polluted areas of the Czech Republic during smog episodes in 1982, 1985, 1987, and 1993. METHODS: Total daily mortality, mortality by gender and age, cardiovascular mortality, respiratory mortality, data on weekly incidence of acute respiratory diseases and daily mean concentrations of sulphur dioxide and suspended particulate matter were used in the model. The effects of smog on daily mortality were estimated by multiple linear regression analysis. RESULTS: Significant increases in mortality were observed for the 1982 and 1987 episodes (6% and 9%). In 1982, mortality was significantly associated with mean concentration of sulphur dioxide (SO2) of the current and the preceding days and with the 4-day moving average. In the 1985 episode a significant increase in respiratory mortality in men and in both genders together, lagging by 2 and 3 days, was detected. During the 1987 episode significant associations of total daily mortality, mortality in persons over 65 years of age and mortality from cardiovascular or respiratory diseases with 4-day moving average of both pollutants were found. For the 1993 episode a significant association between mortality in women under 65, lagging by 3 days, and mean concentration of suspended particulate matter (SPM) was observed. CONCLUSIONS: Most of the results are consistent with other studies aimed at episodic air pollution during the 1950s and 1960s in Western Europe and the USA, in which outdoor air pollution was shown to be a significant predictor of mortality. However, non-significant or opposite associations between air pollution and mortality indicate that other factors may also play an important role. A stronger effect on men under 65 years of age, suggested by a previous Czech study was not confirmed.

[In towns there is a higher prevalence of asthmatic symptoms in children than in rural areas]. / Ve mestech je vetsí prevalence príznaku astmatu detí nez ve venkovských oblastech.

The authors assessed the prevalence of symptoms of bronchial asthma by means of a standardized questionnaire used in the international survey PEACE (Pollution Effect on Asthmatic Children in Europe). The questions about complaints were addressed to children aged 6-13 years (the questionnaires were completed with the parents assistance). In urban areas 5669 children participated from Prague 5, i.e. 35% of all elementary school children, in Teplice 2489 (21% children), in rural areas: in the Benesov district 5619, i.e. 61% children, in the Prachatice district 1983, i.e. 37% children. The response rate of questionnaires in the urban areas was 86-88%, in rural areas 93%. In urban areas the annual prevalence of wheezing in the chest or dyspnoea or possibly both symptoms was within the range of 3.8-13.8% and differed significantly from the prevalence in rural areas where it was 2.4-3.6%. The most frequent symptom was nocturnal dry cough without a cold (in urban areas 14.1-36.7%, in rural areas 6.0-10.6%). Rural areas differed from urban ones by a lower contamination of the atmosphere, a lower density of the population as well as some parameters caused by a different lifestyle.

[Mortality in non-specific respiratory tract inflammation and bronchial obstructive diseases in relation to the environment in the Czech Republic]. / Umrtnost na nespecifické zánety dýchacích cest, na nemoci s bronchiální obstrukcí a vztahy k zivotnímu prostredí v Ceské republice.

BACKGROUND: Despite antibiotic treatment the mortality from inflammations of the airways is still high in our country and worldwide. The objective of the present work is a review of the mortality from respiratory diseases with regard to their prevalence, in relation to gender in the whole Czech Republic and in different regions, in Prague and in southern and northern Bohemia. METHODS AND RESULTS: During the last years the order of mortality from respiratory diseases is as follows: lung cancer, chronic bronchitis and pneumonia, whereby in men the first place is held by lung cancer, in women by pneumonia. In 1992-1994 in the Czech Republic the relative mortality rate from acute bronchitis (bronchiolitis). pneumonia and influenza combined was 24.8, 20.7 and 20.6/100,000 population. In Prague the increment of this mortality was as follows: in 1993-13.5/100,000, in 1994-14.8/100,000. A marked increase was recorded in southern Bohemia (from 16.9 to 26.0) but a drop in northern Bohemia (from 14.5 to 12.2/100,000 population). In 1992 and 1993 in the Czech Republic the number of deaths from diseases associated with respiratory infections -influenza, pneumonia, acute bronchitis (bronchiolitis) and diseases associated with bronchial obstruction (chronic bronchitis, bronchial asthma and pulmonary emphysema) was balanced. In 1994 there was a marked drop in the mortality from diseases with bronchial obstruction as compared with 1993-N 2104/679. In 1994, as compared with 1992 and 1993, the mortality relation in these two groups was reversed and in 1994 mortality from respiratory infections predominates markedly over mortality from obstructions. In Prague infections predominate 1.6 times, in northern Bohemia 1.5 times and in southern Bohemia as much as 3.8 times. CONCLUSIONS: In the Czech Republic the mortality from acute bronchitis (bronchiolitis), pneumonia and influenza combined was in 1993 and 1994 20.7 and 20.6 per 100 000 population. In 1994 the mortality from diseases associated with bronchial obstruction declined markedly, while the mortality from respiratory infections increased in southern Bohemia.

Retinal cysts in the eye of the Asian musk shrew, Suncus murinus, (Mammalia, Insectivora).

The development of retinal cysts in the eye primordia of Suncus murinus embryos was studied. Retinal infoldings were first identified in the 17.5-day-old embryo (crown rump length--CRL = 6.3 mm). At this time, the apex of the developing retinal fold could be identified attached to the lens. The pigmented epithelium did not take part in the formation of the cyst. The retinal fold closed, to form a cyst, by day 23 of embryonic development (CRL = 14.0 mm). The newly formed retinal cyst remained continuous with the retina and extended toward the lens where it attached to the lens epithelium. Retinal cysts had an oval, bilaterally symmetrical shape and a narrow lumen, which, lined by the internal limiting membrane, occasionally contained cellular debris. The dimensions of the cysts were usually 100 to 150 microns (diameter) by 200 to 250 microns (length). Retinal cysts appeared in 45 per cent of the embryos examined.

Acoustic trauma in mineworkers revealed by temporal bone necropsy.

Six selected human cochleae showing definite signs of mechanical damage caused by exposure to high intensity noise (acute acoustic trauma) are reviewed. Patterns of degeneration of cochlear hair cells were compared with the functional audiometric examinations. Tonotopic relations, mechanism of damage to the organ of Corti as well as pathological changes of the tectorial membrane are discussed.

Postnatal development of the organ of Corti in the wild house mouse, laboratory mouse, and their hybrid.

Length of the basilar membrane, number and distribution of cochlear receptors, and the width of the triad of outer hair cells were analyzed in the course of the postnatal development and in adult individuals in wild and laboratory house mice and in hybrids of these species. While in newborn animals the triad of outer hair cells was wide at the base and narrow at the apex, the opposite was true for adult animals. The parameter decreased at the base and increased at the apex during postnatal development. The center of differentiation of (the reticular lamina of) the organ of Corti was localized at 40-50% of the basilar membrane length from the base and corresponded to the region with the maximum density of inner hair cells. The reticular lamina in the apical half of the cochlea matured earlier than in the basal half. Distribution of receptors did not change after birth. The shortest basilar membrane and the slowest rate of maturation were found in wild mice. Hybrids had the longest basilar membrane and the highest rate of maturation. These facts are considered an effect of heterosis.

Effect of ascorbic acid on the numerical hair cell loss in noise exposed guinea pigs.

Two groups of guinea pigs were exposed to 1/3 octave band noise centered at 4 kHz, 113-118 dB SPL, for 2 h. The animals of the first group were treated with ascorbic acid (AA), 0.5 mg per 1 g of body mass injected intraperitoneally before noise exposure. The second group (control) was exposed without being treated. By means of the surface specimen method and consequent assessment of numerical atrophy of cochlear hair cells it was found that application of ascorbic acid before the noise exposure resulted in a lower or no loss of hair cells especially within the respective frequency segment of the basilar membrane. Possible protective effect of AA and/or the negative effect of hypovitaminosis "C" are discussed.

Vacuolar degeneration of the cochlea in young rats.

In the course of investigations of the post-natal development of the ear in Sprague-Dawley rats, a hitherto unrecorded degenerative process was seen in two animals (7-and-8-days old). The process was characterized by vacuolization of almost all the cellular elements of the cochlear tissues. The overall shape and size of the cochlear structures remained well preserved. The organ of Corti did not atrophy but its components were vacuolized, as well as the cells of other inner ear tissues, except for nuclei in the lower part of the modiolus.

Inner ear structure in the deaf and normally hearing Dalmatian dog.

Both cochleae of two 6-week-old Dalmatian dogs of the same litter were examined by means of surface specimens and histological section techniques. Basic quantitative data on the morphometry of the cochlear duct in the hearing (though hypopigmented) pup are presented. The cochlear ducts of the deaf (though normally coloured) pup exhibited in general the same alterations (collapse of the scala media) as described in the literature. In addition, we describe also the coalescence of membranous structures, projection of the tectorial membrane up to the spiral ligament and preservation of inner hair cells in the second (i.e. middle) cochlear coil. These new findings complement the previous data and indicate an alternative possible course of hereditary inner ear degeneration in the Dalmatian dog.