Biomedical subjects

D Helm

Publications and source records attributed to D Helm.

9 recordsLinked to original sources

PubMed2003

Analysis and assessment of heavy metal pollution in suspended solids and sediments of the river Danube.

The Joint Danube Survey (JDS)--a comprehensive monitoring survey to assess the environmental pollution status of the river Danube--was carried out in 2001. Samples were taken at 74 positions along the river from Neu-Ulm (River-km 2589) down to the Danube Delta at the Black Sea (River-km 0) and in 24 main tributaries and anabranches. Besides other biological and chemical parameters, concentrations of Al, As, Cd, Cr, Cu, Fe, Pb, Mn, Hg, Ni, and Zn were determined in sediments and suspended solids. Lowest heavy metal concentrations were measured around River-km 1800. After an increase down to River-km 1000 (the Irongate Reservoir), a constant level or a slight decrease could be found down to and in the Danube Delta. Very high element concentrations were determined at only a few stations of the river Danube and in some tributaries. An evaluation of the pollution status of the river was carried out by enrichment factors (EFs) calculated using adapted background concentrations of heavy metals. Except single sampling sites and some tributaries, the pollution of the river Danube by As, Cr, Cu, Pb, Hg, Ni, and Zn can be regarded as rather low. However, elevated concentrations of Cd were found in both investigated matrices, particularly in the lower stretch of the river Danube beginning at the Irongate.

Environmental Monitoring↗

PubMed2000

Reporting personal results to participants of exposure studies.

In most exposure studies personal results are reported to the participating subjects. This paper describes how this was achieved in two different studies, the large scale German Environmental Survey and the smaller Helsinki part of the multi-national, multi-centre EXPOLIS study. In spite of the different approaches both independently reported personal results in a very similar fashion, involving automation and graphical display of measured values.

Consumer Behavior↗

PubMed1999

[1998 environment survey--initial results].

In close connection with the German National Health Interview and Examination Survey 1998, a third round of the German Environmental Survey (GerES III) was carried out using a random subsample of about 4,500 subjects, which are representative for the German population aged 18 to 69 years. The GerES was carried out by the Federal Environmental Agency on behalf of the Federal Ministry for Environment, Nature Conservation and Reactor Safety. The participants had to undergo an examination in human-biomonitoring. An environmental questionnaire was used to get exposure-related information. Preliminary results indicate a reduction of the body burden with metals in 1998 compared with 1990/92. However, some individuals showed elevated values. For those people health effects are possible or cannot be excluded with sufficient certainty. Using the results of GerES III it will be possible for the first time to establish reference values for organochlorine compounds on a representative data basis. The examination of the tap water used in the subjects households shows that the limit and guideline values of the German Drinking Water Ordinance have not always been met in 1998. This holds especially for lead, copper, and zinc which are being used as pipe-material for domestic plumbing.

Adolescent↗

PubMed1991

Microbiological characterizations by FT-IR spectroscopy.

Infrared signals of microorganisms are highly specific fingerprint-like patterns that can be used for probing the identity of microorganisms. The simplicity and versatility of Fourier-transform infrared spectroscopy (FT-IR) makes it a versatile technique for rapid differentiation, classification, identification and large-scale screening at the subspecies level.

Fourier Analysis↗

PubMed1991

Classification and identification of bacteria by Fourier-transform infrared spectroscopy.

This study describes a computer-based technique for classifying and identifying bacterial samples using Fourier-transform infrared spectroscopy (FT-IR) patterns. Classification schemes were tested for selected series of bacterial strains and species from a variety of different genera. Dissimilarities between bacterial IR spectra were calculated using modified correlation coefficients. Dissimilarity matrices were used for cluster analysis, which yielded dendrograms broadly equated with conventional taxonomic classification schemes. Analyses were performed with selected strains of the taxa Staphylococcus, Streptococcus, Clostridium, Legionella and Escherichia coli in particular, and with a database containing 139 bacterial reference spectra. The latter covered a wide range of Gram-negative and Gram-positive bacteria. Unknown specimens could be identified when included in an established cluster analysis. Thirty-six clinical isolates of Staphylococcus aureus and 24 of Streptococcus faecalis were tested and all were assigned to the correct species cluster. It is concluded that: (1) FT-IR patterns can be used to type bacteria; (2) FT-IR provides data which can be treated such that classifications are similar and/or complementary to conventional classification schemes; and (3) FT-IR can be used as an easy and safe method for the rapid identification of clinical isolates.

Antigens, Bacterial↗

PubMed1978

Modification of the choriogonadotropin beta-subunit radioimmunoassay for determination of urinary choriogonadotropin.

The choriogonadotropin beta-subunit radioimminoassay has been used extensively to measure human choriogonadotropin in the sera of pregnant women and individuals with trophoblastic and nontrophoblastic tumors. Unmodified, this method cannot be used to measure choriogonadotropin in urine because of interfering substances. We circumvented the non-parallelism between the standards and serial dilutions of urine containing choriogonadotropin by adding pooled urine from men to the standard tubes and limiting the volume of urine to 100 microliter. This modified assay has a sensitivity of 3 int. units/liter of urine and is specific for choriogonadotropin concentrations of 40 int. units/liter of urine. Analytical recovery of choriogonadotropin added to urine ranged from 96 to 105%. The within-assay CV was 7.6%; the between-assay CV was 11.8%. Concentrations of choriogonadotropin in concurrently collected serum and urine samples from pregnant women correlated well. The test can be performed within 24 h by using the double-antibody method for separating bound from free hormone, or in 3 h with a dioxane method. The assay is about 20-fold more sensitive than the 2-min or 2-h slide and tube pregnancy tests, and seven-to 12-fold more sensitive than the radioreceptor assay.

Adult↗

PubMed1976

Psychodynamic and behavior modification approaches to the treatment of infantile autism empirical similarities.

In the treatment of infantile autism, behaviorists emphasize directed behavioral change while psychodynamic therapists tend to focus attention on the worker-child relationship. A review of the literature suggests that both of these aspects of intervention are important, and that both play a role in virtually all therapeutic efforts. The similarities in methods of intervention found in the work of investigators of very different theoretical persuasion raise the possibility that most treatment methods owe more to empirical clinical experience than to their presumed derivation from a theoretical model. This thesis is further examined with respect to a 50-year-old case history by Lightmer Witmer, and the work of the present writer with an 11-year-old autistic boy.

Autistic Disorder↗

PubMedDate not supplied

The German Environmental Survey 1990/1992 (GerES II): cadmium in blood, urine and hair of adults and children.

As a follow-up of an earlier population study carried out in West Germany in 1985/1986 (GerES I), a nationwide Environmental Survey was conducted in Germany in 1990-1992 (GerES II). It was the aim of these studies to obtain representative data on the population's body burden and the quality of their indoor environment and immediate surroundings. The present paper reports on cadmium levels in blood, urine and hair of 4021 adults aged 25-69 and 736 children aged 6-14. The statistical analysis included both descriptive and inferential methods. The data were classified according to social factors, lifestyle characteristics, and environmental exposures. Moreover, regression analysis was used to determine the predictors of cadmium concentrations in the types of sample studied. Active cigarette smoking was found to be dominant in affecting blood and urine cadmium levels in adults, but less important for cadmium levels in hair. Age and creatinine level in urine were additional important factors influencing the cadmium concentration in urine, especially in women. Environmental and occupational exposures to cadmium played only a minor role in the exposure models for German adults. The cadmium concentration in blood and urine was generally lower in children than in adults, while no significant difference for cadmium in hair could be detected. The cadmium concentrations in all three samples were significantly higher in East German children than in West German children.

Adolescent↗

PubMedDate not supplied

The German Environmental Survey 1990/1992 (GerES II): reference concentrations of selected environmental pollutants in blood, urine, hair, house dust, drinking water and indoor air.

The German Environmental Survey (GerES) is a large-scale, representative population study that has been carried out three times up to now with a time interval of about 7 years. GerES I was performed in 1985/1986, GerES IIa in 1990/1991 in West Germany, and GerES IIb in 1991/1992 in East Germany, the former German Democratic Republic (GDR). In GerES II, blood, urine, and scalp hair samples of 4021 adults aged 25-69 years and of 736 children aged 6-14 years were analysed as well as environmental samples (house dust, drinking water, indoor and personal air, diet). Characteristics of the frequency distributions of the substances analysed in the different media were calculated. The geometric mean (GM) for lead, cadmium, and mercury in the blood of adults amounted to 45.3, 0.36, and 0.51 microg/l, respectively. The corresponding values of arsenic, cadmium, and mercury in urine were 6.3, 0.29, and 0.54 microg/l, respectively. The concentrations of lead in blood, cadmium in blood and urine, and mercury in blood are lower in children than in adults. The GM ofpentachlorophenol (PCP) in urine of adults was 2.67 microg/l and in urine of children, 4.15 microg/l. These results of GerES II were compared with the so-called HBM values which represent health-based exposure guidelines and have been defined by the Human Biomonitoring Commission (HBC) of the Federal Environmental Agency, interalia for lead in blood, cadmium in urine, mercury in blood and urine, and PCP in urine. They also provided asound basis for the setting of reference values to describe the status of the German population. A total of 1.8% and 0.6% of the German females in child-bearing age had a level of lead in blood higher than HBM-I (100 microg/l) and HBM-II ( 150 microg/l), respectively. One percent of the children had a blood lead level above HBM-I. House dust and drinking water were analysed to characterise exposure in the domestic environment. Arsenic, cadmium, and lead deposition in homes amounted to 5.4 ng/(m2 day), 11.7 ng/(m2 day), and 0.29 microg/(m2 day), respectively. In the content of vacuum cleaner bags, concentrations were 2.1,0.9, and 5.9 microg/g. PCP, lindane and permethrin could be detected in the house dust of most German households. The pollutant load of the drinking water is significantly influenced by the corrosion of pipe materials and fittings. The new EC limit value of 10 microg/l for lead was exceeded in 7.7% of the first draw samples. The relatively high percentage (14%) of samples from East Germany that exceeded the current German guideline value for formaldehyde of 0.1 ppm in indoor air may be explained by the widespread use of contaminated particleboard in the former GDR.

Adolescent↗