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Biomedical subjects

M Schwenk

Publications and source records attributed to M Schwenk.

At least 19 recordsLinked to original sources
PubMed2006

Diagnostic relevance of the determination of lymphocyte subpopulations in environmental medicine.

Earlier hopes that determination of lymphocyte subpopulations might become a strong diagnostic tool in environmental medicine have not been fulfilled in recent years. Analysis of the scientific literature rather shows that there are only few examples for environmental exposures causing reproducible shifts of lymphocyte subpopulations. Moreover, current knowledge suggests that "environmental diseases" are not associated with characteristic changes of subpopulation patterns. If lymphocyte subpopulations are analyzed, each diagnostic step, including indication, sample handling, analytic procedure and data-interpretation, should adhere to good quality criteria. Taking all together, the determination of lymphocyte subpopulations in the context of environmental medicine comes under category IV of the criteria of the Commission for Methods and Quality Assurance in Environmental Medicine of the German federal health authority (Robert Koch-Institute; RKI): "A procedure cannot be recommended because there is not sufficient information to justify it" (here: no solid trends in epidemiological examinations), "and because theoretical considerations speak against an application" (here: high physiological variability and missing exposure or substance specificity).

Antigens, CD↗
PubMed2004

[Multiple Chemical Sensitivity (MCS) -- scientific and health policy aspects].

Multiple Chemical Sensitivity (MCS) is characterized by an increased sensitivity towards chemicals. Many patients with severed unspecific symptoms ascribe these to MCS. At present there is neither a generally accepted diagnosis nor a therapeutic concept. The ENT doctor should look at the nasal airflow resistance, nasal mucosa and olfactory system.

Diagnosis, Differential↗
PubMed2003

[Acute myocardial infarction after blunt polytrauma -- successful coronary intervention].

Acute myocardial infarction following blunt chest trauma is a well reported but rare finding. Especially in severely injured patients the optimal therapy of the myocardial infarction is not well established, since anticoagulants, platelet aggregation inhibitors or thrombolytics are frequently contraindicated under these conditions. We report a case of a 41-year-old man, who presented with an acute myocardial infarction in combination with a severe polytrauma (multiple rib fractures, hematothorax, pelvic bone fractures, multiple injuries of intestinal organs) after a motorcycle accident with a blunt chest and abdominal trauma. After surgical treatment of the injuries of the bones and the intestinal organs a coronary angiography was immediately performed. The left anterior descending and the circumflex coronary artery were occluded in the mid-portion of the vessels. Coronary recanalization by PTCA and the implantation of coronary stents were successful in both vessels. Despite of a non-optimal blood flow after recanalization and stenting in one vessel (LAD TIMI II flow after recanalization), and a non-optimal accompanying medical therapy, during and after intervention (intravenous heparin starting 8 hours after the coronary intervention and platelet inhibitors starting 4 days after the intervention) the coronary angiogram after 2 months documented both vessels patent without a reocclusion or a restenosis. The case report documents, that in traumatic myocardial infarctions the treating of both, the attending injuries and the myocardial ischemia, is feasible. Early coronary angiography and coronary interventions, with or without stent-implantation, are indicated, even in cases in which an adequate accompanying medical therapy with heparin and platelet inhibitors is contraindicated.

Accidents, Traffic↗
PubMed2003

[Nutritional ecology: chances of public health services to shape procedures].

Nutrition ecology is the science that studies the impacts of human nutrition on the environment, on human health and on social systems. Environmental impacts are usually the result of intensive food production, food transport and food packaging; they include soil contamination and erosion, energy consumption, air contamination and waste disposal. Health impacts of contemporary western eating behavior concern nutrition-related diseases (diabetes, hypertension, gout, overweight etc) and their psychological and social consequences; nutrition ecology aims at a balanced diet and suitable eating behavior to reduce the risks of chronic disease. The social impacts of nutrition concern the effects of feed trade on poor working conditions and poverty, especially in developing countries. The strategies of nutrition ecology agree in many points with those of the agenda 21 and of Consumer Protection. As nutrition-related diseases are increasing further, the public health services in Germany discover nutrition as an important topic in health promotion and prevention. They will contribute remarkably to a sustainable development if they include the strategies of nutrition ecology in their projects.

Developing Countries↗
PubMed2003

[10 years of observation by public health offices in Baden-Württemberg--assessment of human biomonitoring for mercury due to dental amalgam fillings and other sources].

Since 1992, in Baden-Württemberg, ten-year old children have been surveyed in the project "Sentinel Health Departments" to study their exposure to environmental pollutants and possible health effects. In the four study areas 1200 children have been investigated every year initially, since 1996 every second year. The data for mercury in body fluids are reported here. The decrease in the body burden of mercury as a result of the declining usage of dental amalgam fillings, was been verified. In 1992/93, of all the children who had been surveyed, the 95 percentile for the body burden of mercury was 3.1 microg/l and in 2000/01 1.35 microg/l. Also to be discussed is the reason why mercury-based cosmetic ointments seriously exceed the HBM-II-intervention-value. Because of using these ointments, concentrations of mercury in urine up to 1400 microg/l were found. A study within the project "Sentinel Health Departments" compared the concentrations of mercury in the urine of adults with those in blood and salvia. The results support the opinion that mercury in urine is appropriate for estimating the mercury uptake from dental amalgam fillings. It can be assumed that these results reflect the situation in the entire Federal Republic of Germany. The ten years' experience confirms that the concept of the "Sentinel Health Departments" is excellently suited to obtain data relevant for environmental health of children. Environmental health protection and the essential gathering of data for future health observation in Baden-Württemberg.

Adult↗
PubMed2003

[Exposition and sensitisation to indoor allergens, house dust mite allergen and cat allergens].

The study examined the exposure to biological indoor air agents and their possible role for allergies and respiratory tract illnesses of children. It was conducted as a case control study (atopic vs non-atopic children) at the four surveillance public health departments in Baden-Württemberg in the winter season 1999/2000 and included 379 children of the fourth class. The concentrations of the house dust mite antigens Der F1, Der p1, and Der Gr2 as well as cat allergen Fel d1 were determined in the children's bedrooms on the ground and in the mattress. Specific IgE-antibodies against allergens from house dust, mites and cat were determined in the serum of the children. For mite allergens the following medians ( micro g/g) were estimated in floor dust: Der p1 = 0.6, Der f1 = 2.3, Gr2 = 0.1; in mattresses: Der p1 = 1.2, Der f1 = 3.4, Gr2 = 0.3. The median of Fel d1 in floor dust was 0.2 microg/g, in mattresses 0.1 microg/g. Sensitisation to dust mite allergen was found to be more prevalent than sensitisation to cat. The distribution of sensitisation among the cases and controls is different. Among the cases, more subjects were sensitised to dust mites (32.9 %) and cat (13.1 %). Among the controls, 17.1 % were sensitised to dust mites and 4.1 % to cat. The results showed no direct association between the prevalence of allergies or respiratory tract illnesses and the indoor concentrations of the allergens. Possible reasons for these findings are discussed.

Allergens↗
PubMed2002

Children as a sensitive subgroup and their role in regulatory toxicology: DGPT workshop report.

There is increasing discussion that children might be considered as a specific subgroup in public health regulations which could be more sensitive than the average "adult" human being. Differences between children and adults, with regard to susceptibility towards toxicants, may result from a combination of toxicokinetic, toxicodynamic and exposure factors. Kinetic factors are of importance mainly in the early postnatal period, largely as the result of immature elimination systems, i.e. metabolising enzymes and/or renal function. Specific vulnerability may prevail during several time periods, related to the development and maturation of organs (for example, brain, bone, endocrine system). For some substances, it has been shown that children at a specific age are less sensitive than adults. Specific exposures of toddlers to environmental chemicals may be high due to their moving behaviour and hand-to-mouth activities. Existing scenarios and models for exposure of children should be improved, in particular with respect to different ages. The outcome of model calculations must be verified by human biomonitoring analysis. At present, there is ongoing discussion of toxicological test models suitable to delineate human postnatal development. Experience with infant-orientated test systems is scarce (for example in developmental neurotoxicity). In general, tools for predicting toxicological sensitivity of children must be further improved. Regulators should also be aware that reduction of lifestyle-related toxic exposures such as smoking and drug abuse in children and adolescents is now an increasing public health problem in many countries.

Adolescent↗
PubMed2002

Human biomonitoring of polychlorinated biphenyls and polychlorinated dibenzodioxins and dibenzofuranes in teachers working in a PCB-contaminated school.

Eighteen teachers from a highly contaminated school and 11 teachers from a control school participated in this study. Total polychlorinated biphenyl (PCB) indoor air concentration (six indicator congeners x 5) was beyond 12000 ng/m3 in some rooms of the contaminated school. PCB 28 and PCB 52 were the prevailing congeners. Whole blood was taken from each participant by the local health authority, pooled in two groups and analysed for the six PCB indicator congeners, non-ortho PCBs and polychlorinated dibenzodioxins (PCDD)/polychlorinated dibenzofurans (PCDF). Blood analysis showed elevated mean PCB 28 and PCB 52 levels for the exposed group, however the two groups were almost identical with regard to PCB 101, 138, 153 and 180. Moreover no difference can be observed for the concentration of non-ortho PCBs and PCDD/PCDF. The data support the finding, that heavy indoor air contamination with low chlorinated PCBs causes an increase of PCB 28 and PCB 52 blood levels. However, this increment was small compared to their total PCB load.

Adult↗
PubMed2002

[Serum selenium levels in school children: results and health assessment].

BACKGROUND: In Germany, where geogenic selenium concentrations are low, only few data on selenium status in children are available. Aim of the study was to investigate serum selenium concentrations of children in a population-based sample and to additionally investigate spatial and temporal differences. METHOD: In three consecutive cross sectional studies the selenium concentration in serum was determined in 1,918 children (mean age 10.3 years) from four study areas. Potential factors of influence were assessed by questionnaires filled in by parents and physicians, respectively. Selenium determination was done by hydride atomic absorption spectrometry after microwave digestion. RESULTS: Mean selenium concentrations for the subcollectives ranged from 54.5 +/- 10.5 micro g/l to 71.9 +/- 15.1 micro g/l. The minimum observed was 14 micro g/l, the maximum 216 micro g/l. Turkish children had lower selenium concentrations than German children and children of other nationality, respectively. Controlling for sex and year of investigation German children from Stuttgart had significantly lower selenium concentrations than children from Aulendorf/Bad Waldsee. In the same regression model for the period from 1995/96 to 1998/99 a decreasing trend was found to be significant. However, the regression model only explains a very small part of variance. CONCLUSIONS: The selenium concentrations determined in this study are in the range also found in other studies in children from Germany. They are far below the toxicologically relevant range, which starts at about 600 micro g/l. The 5 th percentile in nearly all subcollectives was below the threshold limit of the lower tolerable selenium concentration of 45 micro g/l. For children from south Germany deficiency of selenium is therefore more to be suspected than a burden relevant to health. Selenium supplementation should however be considered thoroughly. Balanced nutrition is also a main factor for an optimum selenial supply.

Child↗
PubMed2001

[Assessment of mould pollution in residences in southwest Germany].

Elevated levels of moulds in homes may represent a risk for development of allergies and respiratory diseases. Little is known about the levels of these biogenic contaminants in homes in South-West Germany. This paper presents the results of a study which was performed between November 1997 and May 1998 in the four Sentinel Health Departments in Baden-Württemberg (Stuttgart, Mannheim, Kehl and Aulendorf/Bad Waldsee). It included 377 households in which children of 10 years of age resided. Moulds were determined in indoor air, outdoor air, household dust from floors and mattresses. Specific home characteristics were assessed by questionnaire. The median value of the number of colony forming units (CFU) in indoor air was 135 CFU/m3 (range 5-17,000) and in outdoor air 145 CFU/m3 (range 15-2,900). The median value of CFU/g dust, collected from the floors, was 15,000 (range 0-700,000) and collected from mattresses was 28,000 (range 1,500-1,350,000). The data suggest that an indoor-outdoor difference exceeding the value of 500 CFU/m3 indicates an elevated mould concentration in indoor air compared to background. This value can be discussed as a temporary reference value for South-West Germany in the winter season. However, a health assessment can not be derived from this value.

Air Microbiology↗
PubMed1999

Stability of isoflavones during extrusion processing of corn/soy mixture.

The influence of extrusion processing in the presence of corn on the quantity and quality of genistein, daidzein, and their respective beta-glucoside, acetyl glucoside, and malonyl glucoside derivatives was evaluated. Products of 100% soy (textured) and a blend of 20% soy protein concentrate (SPC) and 80% corn meal (direct-expanded) were extruded, with evaluations before and after extrusion. In addition, a 3 x (3 x 3) split-plot factorial experiment investigated the influence of barrel temperature (110, 130, 150 degrees C), moisture content (22, 24, 26%), and relative residence time (1, 0.8, 0.6) on extruder response and isoflavone profile. The extrusion barrel temperature had the most influence on isoflavone profile, especially decarboxylation of the malonyl beta-glucoside, followed by the moisture content. The amount of extractable isoflavones decreased after extrusion for both the SPC and SPC/corn meal blend when extracted with 80% aqueous methanol but remained approximately the same when first hydrated with water before extraction. However, initially hydrating with water produced enzymatic glycolysis in the unextruded samples, increasing the aglycons dramatically.

Food Handling↗
PubMed1997

[Poisoning of a family by a mercury-containing ointment].

Within the framework of a project entitled "Observation by Public Health Offices" we discovered a strikingly high mercury concentration of 30 micrograms in the urine of a 10-year old girl from an Albanian family formerly residing in the Kosovo area in Serbia. We investigated into the cause of this mercury load and found that it was also present in other members of the same family. Symptoms of mercury poisoning were evident to varying degrees in individual family members. Ultimately, we traced the source to a bleaching ointment containing mercury. On analysing the same we found a mercury content of 389 mg per g ointment. The use of this ointment with its extremely high mercury content had also contaminated the living-rooms.

Adolescent↗
PubMed1996

First data on background levels of non-ortho and mono-ortho PCBs in blood of residents from southern Germany.

Blood-fat concentrations of polychlorinated biphenyls (PCB) congeners: no. 105, 118, 156 (mono-ortho-substituted) and no. 77, 126, 169 (non-ortho-substituted) and PCB congeners no. 28, 52, 101, 138, 153 and 180 were measured. The investigations were carried out in pooled samples from children and in individual samples from adults. Additionally polychloro-p-dibenzodioxins and -furans (PCDD/PCDF) were investigated.

Adipose Tissue↗
PubMed1996

Cultured gastric parietal cells from the guinea pig: adherence, cell growth and stimulus coupling of Ca2+ and cyclic AMP.

The aim of the study was to establish cell culture conditions for responsive guinea pig parietal cells. Parietal cells were isolated by a pronase/collagenase method, enriched by counterflow elutriation and cultured on plastic culture dishes in minimum essential medium. Precoating with gelatine or collagen increased adherence; optimum fetal calf serum concentration was 10%. Parietal cells were cultured for up to 120 h. Intracellular calcium levels in cells cultured for 48 h were 150 nmol/l and increased to 320 nmol/l after stimulation with carbachol and to 250 nmol/l after histamine stimulation as determined by video imaging microscopy. Intracellular cyclic AMP levels were increased 9-fold by histamine in cells cultured for 24 h and more than 30-fold in cells cultured for 48 h. The results show that guinea pig parietal cells grow in primary culture and are suitable for studying second messenger coupling.

Animals↗
PubMed1996

Bicarbonate secretion in the guinea pig duodenum: functional characterization of peptide hormone receptors in duodenal enterocytes.

To get information about the peptide hormone receptors involved in duodenal bicarbonate secretion (DBS) and their cellular location, we determined DBS and adenylate cyclase (AC) activity in response to hormones of the vasoactive intestinal polypeptide (VIP)/secretin family of peptides. DBS was determined in an isolated, perfused (24 mmol/1 NaHCO3) loop of the proximal duodenum in urethane- and indometacin-treated guinea pigs. AC stimulation was measured in isolated, homogenized duodenal enterocytes, the histological evaluation of which revealed their villous origin. VIP (10(-9) to 10(-7) mol x kg-1) dose-dependently increased DBS 3.5-fold (p < 0.01); this effect was completely inhibited by the VIP antagonist [D-p-Cl-Phe6,Leu17]VIP (10(-6) mol x kg-1). Glucagon (10(-8) to 10(-6) mol x kg-1) increased DBS 2.1-fold, while secretin (10(-9) to 10(-6) mol x kg-1) had no effect on DBS, but stimulated pancreatic bicarbonate secretion. VIP concentration-dependently increased AC activity 5.6-fold with an EC50 of 1.3 x 10(-9) mol/l. [D-p-Cl-Phe6,Leu17]VIP caused a rightward shift of the VIP concentration-response curve. A Schild plot analysis yielded a slope of 0.85 +/- 0.11, indicating competitive inhibition. While secretin also stimulated AC activity, although 1,000-fold less potent than VIP, glucagon was ineffective. These data indicate that specific VIP receptors, which mediate VIP-stimulated bicarbonate secretion, are present on villous enterocytes. Stimulation of AC by secretin seems to be of pharmacological relevance only and is consistent with the lack of effect of this hormone on DBS. Glucagon likely activates a second transmitter of bicarbonate secretion, or works independently of AC.

Adenylyl Cyclases↗
PubMed1996

Role of protein kinase C in duodenal mucosal bicarbonate secretion in the guinea pig.

Since duodenal bicarbonate secretion (DBS) is increased by m-cholinoceptor agonists, it was postulated that protein kinase C (PKC) has a role in this secretion. This premise was examined in guinea pigs, using 12-O-tetradecanoyl-phorbol 13-acetate (TPA) to stimulate bicarbonate production in the perfused duodenum in vivo, and to activate PKC in isolated duodenal enterocytes. TPA (10(-7) mol.kg-1) infused intravenously stimulated active DBS from basal values of 3.64 +/- 0.66 to 8.73 +/- 1.59 mumol.cm-1.10 min-1. This effect was completely blocked by verapamil (4 x 10(-7) mol.kg-1). PKC activity in duodenal enterocytes in the basal state was most abundant in the cytosolic fraction (2,221 +/- 444 U/mg protein) and very low in the particulate fraction (227 +/- 51 U/mg protein). TPA (10(-7) mol.kg-1) caused a time-dependent translocation of the cytosolic, lipid-dependent activity of PKC into the particulate fraction. The effect was maximal at 5 min incubation and was reversed by 30 min. In the particulate fraction, this activity was no longer lipid-dependent, but could be stimulated by Ca2+ alone. These data support the hypothesis that translocation of PKC may contribute to DBS.

Animals↗
PubMed1995

Effect of somatostatin-14 on duodenal mucosal bicarbonate secretion in guinea pigs.

The role of somatostatin-14 in duodenal mucosal HCO3- secretion was investigated in anesthetized, indomethacin-treated guinea pigs. Net HCO3- output from the isolated, perfused (24 mM NaHCO3 + 130 mM NaCl) proximal duodenum was measured during intravenous infusion (alone or in combination) of somatostatin-14, carbachol, vasoactive intestinal peptide (VIP), and prostaglandin E2 (PGE2). In homogenates of duodenal enterocytes, the effect of these agents on adenylate cyclase activity was studied. Basal duodenal HCO3- secretion (3.5 +/- 0.2 mumol/cm/10 min) was reduced dose dependently by somatostatin-14 (10(-11) mol/kg, 10(-9) mol/kg, and 10(-7) mol/kg). Carbachol, VIP, and PGE2 (all 10(-8) mol/kg) increased basal duodenal HCO3- secretion two- to threefold. Somatostatin-14 (10(-7) mol/kg) abolished the stimulatory effect of carbachol and VIP, but not that of PGE2. Basal adenylate cyclase activity in isolated duodenal enterocytes (9.4 +/- 1.0 pmol cAMP/mg protein/min) was unaltered by somatostatin (10(-6) mol/liter) or carbachol (10(-3) mol/liter). VIP (10(-8) mol/liter) and PGE2 (10(-7) mol/liter) increased adenylate cyclase activity two- to threefold, and these effects were unchanged by somatostatin-14 (10(-6) mol/liter). In conclusion, somatostatin-14 inhibits basal and carbachol- and VIP-stimulated duodenal HCO3- secretion, and its mechanism of action is not via inhibition of adenylate cyclase activity in duodenal enterocytes.

Adenylyl Cyclases↗