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Biomedical subjects

W Bischof

Publications and source records attributed to W Bischof.

At least 37 records · Page 2Linked to original sources
PubMed2000

Indoor determinants of Der p 1 and Der f 1 concentrations in house dust are different.

BACKGROUND: Exposure to mite allergens is a major risk factor for sensitization and the development of asthma. Der p 1 and Der f 1 content in homes and probably the proportion of both antigens is highly variable even in the same geographical area. OBJECTIVE: We investigated specific indoor determinants of Der p 1 and Der f 1 concentrations in house dust of two German cities, Erfurt and Hamburg (n = 405 homes). METHODS: Mite allergen levels were determined using monoclonal antibodies against Der p 1 and Der f 1 by the ELISA method. Indoor relative humidity and temperature were monitored continuously in the homes over 1 week. The characteristics of homes and occupants were assessed by questionnaire to obtain information on factors which may have an impact on the mite antigen concentration in house dust. These determinants were studied by multivariate regression analysis. RESULTS: The correlation between concentrations of Der p 1 and Der f 1 inside the homes was weak (r = 0.29-0.35), indicating that different determinants are relevant. Concentrations of the allergens were significantly higher on lower floors (ratios 2-8 times, Der p 1, Der f 1), on old mattresses (ratios 3-13 times, Der p 1, Der f 1), in post-war buildings (ratio 6 times, Der p 1), for non-central heating (ratio 2 times, Der p 1), for old carpets (ratio 3 times, Der p 1) and for the presence of a dog in the house (ratio 3 times, Der f 1). Furthermore, mite concentration increases with raising relative humidity (ratio 1.03 per 1%, Der p 1) and with decreasing temperature (ratio 0.86 per 1 degrees C, Der p 1) indoors. CONCLUSION: Both Der p 1 and Der f 1 concentrations should be measured in house dust, since they are only weakly correlated and have different determinants.

Adult↗
PubMed1998

[Determination of NO2 exposure--personal passive sampling versus indoor measurement].

Measurements of NO2 exposure of 29 inhabitants of Erfurt were carried out using personal passive samplers along with stationary passive samplers (indoor and outdoor) at the subjects' apartments and at their work places. The time adjusted results of the stationary measurements were compared with the results of the personal measurements and the differences (mean: 3, 15; max: +47; min: 14, 1 in ppb) were analysed. A multitude of recorded facts (e.g. use of gas stoves, smoking in the apartment) and factors which could not be quantified (e.g under- or over-estimation of the real impact of the pollutant on the person) results in disparities between the personal and stationary measured data. Though people spent 90% of the 48 hours measurement period indoors, time weighted stationary measurements of NO2 cannot replace personal measurements. For evaluation of health problems, lack of well being and work efficiency personal measurements are preferable.

Air Pollutants↗
PubMed1994

Detection of early lung impairment with aerosol bolus dispersion.

The broadening of inhaled aerosol boluses (aerosol bolus dispersion) during respiration provides a noninvasive measure of convective gas mixing in the lungs. In this study, the sensitivity and specificity of this technique for the diagnosis of early lung impairment due to cigarette smoking was evaluated. Two hundred and sixteen randomly selected subjects (126 smokers and 90 nonsmokers) were investigated with aerosol dispersion in comparison to conventional lung function tests. The cumulative cigarette consumption of the subjects was quantified by "pack-years" (PY). Smokers were classified into the following groups: 0 < PY < or = 10; 10 < PY < or = 20; 20 < PY < or = 30; and PY > 30. Forced expiratory volume in one second (FEV1), maximal expiratory flow at 25, 50 and 75% vital capacity (MEF25, MEF50 and MEF75) decreased significantly with increasing cigarette consumption. In comparison to nonsmokers, FEV1 was significantly reduced in smokers of 10 < PY < or = 30, and MEF75 was significantly reduced in smokers of PY > 20. Aerosol bolus dispersion increased with increasing PY. For all groups of smokers, even those with PY < 10, bolus dispersion was significantly increased in comparison to lifelong nonsmokers, indicating alterations in convective gas mixing in the lungs. Calculation of receiver operating characteristics for the lung function parameters under consideration showed that bolus dispersion has a higher sensitivity and specificity than conventional lung function parameters. Hence, the aerosol bolus dispersion test could be a promising epidemiological tool to study early abnormalities in intrapulmonary gas mixing due to environmental factors.

Adult↗
PubMed1989

[Physiologic adaptation of the thermal manikin].

At present time thermal manikins (TM) are used as standard method to determine the thermal quality of clothing. Besides, in the last time TM's apply to estimate indoor climate. Now used types of TM enable quantitative assertions on human convective and conductive heat exchange, as for the whole body as for different parts. The limited factor for this heat flow is the topical value of TM's skin temperature which is regulated by software. As a rule, this temperature is the same like human's skin temperature at thermal comfort conditions. Distal change of skin temperature takes a leading part to determine thermal conditions which are still tolerable regarding human thermoregulation. The influence of this kind of thermal regulation on topical convection and conductive heat exchange was examined by variation of TM's skin temperature on a concrete indoor situation and defined clothing and metabolic conditions.

Body Temperature Regulation↗
PubMed1987

PIXE analysis in different stages of psoriatic skin.

Elemental distribution in psoriatic skin varies with the functional state of the keratinocytes, e.g., electrolytes influence cell metabolism and cell proliferation, and trace elements play a crucial role in a great number of enzymes. Elemental distribution in pinpoint lesions, old plaques, and uninvolved skin of 5 psoriatic patients and 4 healthy controls was studied by means of PIXE (proton-induced x-ray emission) analysis. This technique allows the simultaneous detection of elements with an atomic number greater than or equal to 14 along the epidermis and dermis in freeze-dried skin biopsies. Trace elements such as Fe, Cu, and Zn were determined down to a level of 1 ppm. In comparison with uninvolved skin, concentrations of P and K were elevated in psoriatic epidermis. In addition, increased levels of K were correlated with the stage of the psoriatic lesion. Zinc concentrations were significantly elevated in pinpoint lesions. The Zn concentration profiles within the epidermis and upper dermis showed high correlation to the P concentration profiles. Iron levels were decreased in old psoriatic plaques, whereas Cu concentrations varied considerably. In comparison to the controls, Cl concentrations were markedly decreased in the dermis of involved and uninvolved psoriatic skin, whereas epidermal Cl levels were unaffected. As high K levels prevent the Ca-induced differentiation of keratinocytes, high K levels may be the cause of the high cell differentiation in psoriatic skin. Elevated DNA- and RNA-polymerases might be the cause of elevated Zn levels in pinpoint lesions.

Adult↗
PubMed1982

Age-dependent changes in the carbohydrate pattern of human prostatic epithelium as determined by peroxidase-labeled lectins.

Peroxidase-conjugated lectins (peanut agglutinin: PNA; Ricinus communis agglutinin: RCA) were used for histochemical demonstration of the respective carbohydrate binders (PNA: beta-D-galactosyl-(1-3)-N-acetyl-galactosamine; RCA: D-galactose). The study of prostatic specimens from four different age groups showed marked differences in cytoplasmic PNA binding of prostatic epithelium. The basal cells of the glandular epithelium displayed cytoplasmic PNA binding only in the infantile stage and during early puberty. With the onset of puberty a number increasing with age of secretory cells developed cytoplasmic binding of PNA, mostly appearing as apically located vacuoles. Intraluminal secretion, however, was never stained. During senile involution the prostatic epithelium lost rapidly its PNA binding capacity. Since no RCA binding of the epithelium was observed, the carbohydrate moiety responsible for PNA binding presumably represents a galactosyl-N-actyl-galactosamine containing molecule, most likely a glycoprotein, which is present in actively functioning prostatic epithelial cells. It is uncertain whether or not it represents a structural or a secretory component of the prostatic cell.

Adolescent↗
PubMed1977

[The legal terms "controlled area" and "X-ray room" in the x-ray ordinance of 1973 (author's transl)].

The X-ray Ordinance of 1973 defines the legal terms "controlled area" (sec. 15) and "X-ray room" (sec. 16) differently, serving different legal purposes. For the application and interpretation the two terms are to be distinguished. The competence to locate the limits of the "controlled area" lies with the radiation protection officer according to secs. 11, 12, and 15 of the X-Ray Ordinance. He is authorized to enlarge the "controlled area" and to make its limits identical with those of the X-ray room. The State authorities may intervene in this primary competence of the radiation protection officer only in exceptional cases (15 subsec. 4). The competent State authority may ask the radiation protection officer to enlarge a "controlled area" if it seems necessary for the protection of individuals or of the public. However, a general order of the supervisory authority implicating identical definition of "controlled area" and "X-ray room" would be inconsistent with the explicit provisions of the X-ray Ordinance and therefore unlawful.

Germany, West↗