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PubMed1993

The Jülich Environmental Specimen Bank.

The environmental specimen bank of the Federal Republic of Germany represents the modern form of a systematically designed archive for the preservative storage of selected environmental specimens. Major aims of environmental specimen banks are: (i) retrospective identification and quantification of environmental chemicals including those not known at the time of storage; (ii) retrospective replicate analysis of samples stored under preservative conditions for the determination of inorganic elements or organic compounds already examined; and (iii) retrospective control of the success of legislative environmental protection measures in handling chemicals regarded as hazardous for man and the environment. Results of the environmental specimen bank at Jülich by the Institute of Applied Physical Chemistry, Research Centre Jülich, KFA, obtaining the initiated legislative regulations providing environmental pollution, are already proved for various compartments.

Animals↗
PubMed1976

Evolution of continuous variation: direct approach through joint distribution of genotypes and phenotypes.

The evolutionary dynamics of the joint distribution of genotypes and phenotypes is studied. The model, originally devised to study the joint effects of Mendelian and other types of transmissions, provides results of interest also to the theory of direct Mendelian transmission with natural selection. Assuming bivariate normal distributions, it is shown that in the latter case genotypic and phenotypic means and variances, and genotype-phenotype correlation can be expressed recursively as functions of the parameters for the selection, environmental, and mutation variance. Equilibria and rates of approach for these moments are calculated. It is also proved that in the presence of selection the heritability,defined as the ratio of expected genotypic to expected phenotypic variance after selection, is greater than that before selection by a predictable amount and that it can be greater than unity.

Biological Evolution↗
PubMed1996

Environmental estrogens: effects on cholesterol lowering and bone in the ovariectomized rat.

Representative non-steroidal estrogens, from common environmental sources such as plants, pesticides, surfactants, plastics, and animal health products, demonstrated an ability to lower serum cholesterol and prevent bone loss. Specifically, select environmental estrogens (coumestrol, genistein, methoxychlor, bisphenol A, and zeranol) effectively lowered total serum cholesterol in an estrogen-dependent animal model, the ovariectomized rat. Of these entities, coumestrol, methoxychlor, and zeranol prevented ovariectomy-induced bone loss. In an in vitro environment, these compounds competed with 17beta-estradiol for estrogen receptor binding and stimulated cell proliferation in a human breast cancer cell line (MCF-7). In addition to their well-documented effects on reproductive tissue, various environmental estrogens can dramatically affect non-reproductive parameters such as cholesterol lowering and bone metabolism.

Adenocarcinoma↗
PubMed2002

Molecular ecology of toxigenic Vibrio cholerae.

Toxigenic Vibrio cholerae is the etiological agent of cholera, an acute dehydrating diarrhea that occurs in epidemic form in many developing countries. Although V. cholerae is a human pathogen, aquatic ecosystems are major habitats of Vibrio species, which includes both pathogenic and nonpathogenic strains that vary in their virulence gene content. V. cholerae belonging to the 01 and 0139 serogroups is commonly known to carry a set of virulence genes necessary for pathogenesis in humans. Recent studies have indicated that virulence genes or their homologues are also dispersed among environmental strains of V. cholerae belonging to diverse serogroups, which appear to constitute an environmental reservoir of virulence genes. Although the definitive roles of the virulence-associated factors in the environment, and the environmental selection pressures for V. cholerae-carrying virulence genes or their homologues is not clear, the potential for origination of new epidemic strains from environmental progenitors seems real. It is likely that the aquatic environment harbors different virulence-associated genes scattered among environmental vibrios, which possess a lower virulence potential than the epidemic strains. The ecosystem comprising the aquatic environment, V. cholerae, genetic elements mediating gene transfer, and the mammalian host appears to support the clustering of critical virulence genes in a proper combination leading to the origination of new V. cholerae strains with epidemic potential.

Cholera↗
PubMed1992

Toxicity assessment of atrazine, alachlor, and carbofuran and their respective environmental metabolites using Microtox.

Using the Microtox method of toxicity assessment designed by Microbics Corporation, the relative toxicities of alachlor, atrazine, and carbofuran, three pesticides commonly used in agricultural production, were determined. Generally, carbofuran was found to be most acutely toxic, followed closely by atrazine. Alachlor was least toxic of the three pesticides tested. Selected environmental metabolites of these three agri-chemicals were also tested using the same method. Hydroxyalachlor, deethylatrazine, deisopropylatrazine, 3-hydroxycarbofuran, and 3-ketocarbofuran were selected for analysis because previous studies determined their presence in surface and ground-water supplies along with their parents. Results showed that often the metabolites were at least as acutely toxic as their parents, particularly in the case of 3-ketocarbofuran and hydroxyalachlor, which demonstrated toxicities higher or not significantly different than their parents. Hydroxycarbofuran was assessed as the least toxic of all substances tested. The atrazine environmental metabolites were less toxic than their parent.

Acetamides↗
PubMed1997

Is there an association between exposure to environmental estrogens and breast cancer?

It was initially reported that levels of polychlorinated biphenyls (PCBs) or p,p'-DDE were elevated in breast cancer patients (serum or tissue) versus controls. These results, coupled with reports that selected environmental estrogens decreased 17beta-estradiol (E2) 2-hydroxylase activity and increased the ratio of 16alpha-hydroxyestrone/2-hydroxyestrone metabolites in MCF-7 human breast cancer cells, have led to the hypothesis that xenoestrogens are a preventable cause of breast cancer. More recent studies and analysis of organochlorine levels in breast cancer patients versus controls show that these contaminants are not elevated in the latter group. Moreover, occupational exposure to relatively high levels of PCBs and DDT/DDE are not associated with an increased incidence of breast cancer. A reexamination of the radiometric E2 2-hydroxylase assay in MCF-7 cells with diverse estrogens, antiestrogens, and carcinogens showed that the mammary carcinogen benzo[a]pyrene induced this response and the antiestrogen ICI 164,384 decreased E2 2-hydroxylase activity. Thus, E2 2-hydroxylase activity and the 16alpha-hydroxyestrone/2-hydroxyestrone metabolite ratio in MCF-7 cells does not predict xenoestrogens or mammary carcinogens.

Breast Neoplasms↗
PubMed2005

Kinetics of the oxidation of phenols and phenolic endocrine disruptors during water treatment with ferrate (Fe(VI)).

The ability of ferrate (Fe(VI)) to oxidize phenolic endocrine-disrupting chemicals (EDCs) and phenols during water treatment was examined by determining the apparent second-order rate constants (k(app0) for the reaction of Fe(VI) with selected environmentally relevant phenolic EDCs (17alpha-ethinylestradiol, beta-estradiol, and bisphenol A) and 10 substituted phenols at pH values ranging from 6 to 11. The three selected groups of EDCs showed appreciable reactivity with Fe(VI) (kapp at pH 7 ranged from 6.4 x 102 to 7.7 x 10(2) M(-1) s(-1)). The k(app) for the substituted phenols studied at pH 7 ranged from 6.6 to 3.6 x 10(3) M(-1) s(-1), indicating that many other potential phenolic EDCs can be oxidized by Fe(VI) during water treatment. The Hammett-type correlations were determined for the reaction between HFeO4- and the undissociated (log(k) = 2.24-2.27sigma+) and dissociated phenol (log(k) = 4.33-3.60sigma+). A comparison of the Hammett correlation obtained for the reaction between HFeO4- and dissociated phenol with those obtained from other drinking water oxidants revealed that HFeO4- is a relatively mild oxidant of phenolic compounds. The effectiveness of Fe(VI) for the oxidative removal of phenolic EDCs was also confirmed in both natural water and wastewater.

Endocrine Disruptors↗
PubMed2005

Copper amendment of agricultural soil selects for bacterial antibiotic resistance in the field.

AIMS: The objective of this study was to determine whether Cu-amendment of field plots affects the frequency of Cu resistance, and antibiotic resistance patterns in indigenous soil bacteria. METHODS AND RESULTS: Soil bacteria were isolated from untreated and Cu-amended field plots. Cu-amendment significantly increased the frequency of Cu-resistant isolates. A panel of isolates were characterized by Gram-reaction, amplified ribosomal DNA restriction analysis and resistance profiling against seven antibiotics. More than 95% of the Cu-resistant isolates were Gram-negative. Cu-resistant Gram-negative isolates had significantly higher incidence of resistance to ampicillin, sulphanilamide and multiple (> or =3) antibiotics than Cu-sensitive Gram-negative isolates. Furthermore, Cu-resistant Gram-negative isolates from Cu-contaminated plots had significantly higher incidence of resistance to chloramphenicol and multiple (> or =2) antibiotics than corresponding isolates from control plots. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this field experiment show that introduction of Cu to agricultural soil selects for Cu resistance, but also indirectly selects for antibiotic resistance in the Cu-resistant bacteria. Hence, the widespread accumulation of Cu in agricultural soils worldwide could have a significant effect on the environmental selection of antibiotic resistance.

Agriculture↗
PubMed1994

Environmental risk factors and multiple sclerosis: a community-based, case-control study in the province of Ferrara, Italy.

The frequency of multiple sclerosis (MS) in Italy and in other areas of the world seems to have increased over time, suggesting that some environmental factors operate in its etiology. We performed a retrospective, community-based case-control study on MS in order to verify the etiologic role of selected environmental factors. We found an association between MS and higher educational level, employment in public administration, past history of allergies, and infection at an early age with measles, rubella and whooping cough. Our data seem to confirm that exogenous factors play a role in the etiology of MS although some confounding variables could have accounted for the associations.

Adult↗
PubMed2004

The effect of an infant's environmental conditions and state of health on the teething of the primary incisors.

The objective of this research was to determine the relationship between the time when an infant's first incisor teething occurred, the infant's state of health and selected environmental and living conditions. 483 infants participated in this research and their health development was monitored monthly in a local hospital in Wroclaw. The teething of the infants was studied from the time of their birth until the age of 18 months. The descriptions of the infants' living and environmental conditions and their developmental stages were analysed on the basis of 10 standardised characteristics. The results of this study showed that there were strong relationships between the teething of infants' incisors, their living conditions and individual progress in health development.

Adolescent↗
PubMed2002

The Long Island Breast Cancer Study Project: description of a multi-institutional collaboration to identify environmental risk factors for breast cancer.

The Long Island Breast Cancer Study Project is a federally mandated, population-based case-control study to determine whether breast cancer risk among women in the counties of Nassau and Suffolk, NY, is associated with selected environmental exposures, assessed by blood samples, self-reports, and environmental home samples. This report describes the collaborative project's background, rationale, methods, participation rates, and distributions of known risk factors for breast cancer by case-control status, by blood donation, and by availability of environmental home samples. Interview response rates among eligible cases and controls were 82.1% (n = 1,508) and 62.8% (n = 1,556), respectively. Among case and control respondents who completed the interviewer-administered questionnaire, 98.2 and 97.6% self-completed the food frequency questionnaire; 73.0 and 73.3% donated a blood sample; and 93.0 and 83.3% donated a urine sample. Among a random sample of case and control respondents who are long-term residents, samples of dust (83.6 and 83.0%); soil (93.5 and 89.7%); and water (94.3 and 93.9%) were collected. Established risk factors for breast cancer that were found to increase risk among Long Island women include lower parity, late age at first birth, little or no breast feeding, and family history of breast cancer. Factors that were found to be associated with a decreased likelihood that a respondent would donate blood include increasing age and past smoking; factors associated with an increased probability include white or other race, alcohol use, ever breastfed, ever use of hormone replacement therapy, ever use of oral contraceptives, and ever had a mammogram. Long-term residents (defined as 15+ years in the interview home) with environmental home samples did not differ from other long-term residents, although there were a number of differences in risk factor distributions between long-term residents and other participants, as anticipated.

Adult↗
PubMed2006

Relating environmental variation to selection on reaction norms: an experimental test.

Theoretical models predict that selection on reaction norms should depend on the relative frequency of environmental states experienced by a population. We report a laboratory experimental test of this prediction for thermal performance curves of larval growth rate in Pieris rapae in relation to their thermal environment. We measured short-term relative growth rate (RGR) for each individual at a series of five temperatures, and then we assigned individuals randomly to warm or cool selection treatments, which differ in the frequency distributions of environmental temperatures. Selection gradient analyses of two independent experiments demonstrated significant positive selection for increasing RGR, primarily through its effects on survival to adulthood and on development rate. In both the warm and cool selection treatments, the magnitude of directional selection on RGR was consistently greater at lower (suboptimal) temperatures than at higher temperatures; differences in selection between the treatments did not match model predictions. The temporal order and duration of environmental conditions may affect patterns of selection on thermal performance curves and other continuous reaction norms, complicating the connections between variation in environment, phenotype, and fitness.

Animals↗
PubMed1997

In vitro synergistic interaction of alligator and human estrogen receptors with combinations of environmental chemicals.

The effect of mixtures of environmental chemicals with hormonal activity has not been well studied. To investigate this phenomenon, the estrogen receptor (ER) from the American alligator (aER) or human (hER) was incubated with [3H]17beta-estradiol in the presence of selected environmental chemicals individually or in combination. The environmental chemicals included the insecticide chlordane, which has no estrogenic activity, and the pesticides dieldrin and toxaphene, which have very weak estrogenic activity. Chlordane, dieldrin, and toxaphene individually demonstrated no appreciable displacement of [3H]17beta-estradiol from aER and hER at the concentration tested. A combination of these chemicals inhibited the binding of [3H]17beta-estradiol by 20 to 40%. Alachlor, a chemical recently discovered to have weak estrogenic activity, also displaced [3H]17beta-estradiol more effectively in combination with dieldrin than alone. These results indicate that combinations of some environmental chemicals inhibit [3H]17beta-estradiol binding in a synergistic manner. This suggests that the ER may contain more than one site for binding environmental chemicals. The possibility that the ER binds multiple environmental chemicals adds another level of complexity to the interaction between the environment and the endocrine system.

Acetamides↗
PubMed1992

Effects of pollution on swallowing: how little we know.

Swallowing is an essential function of the upper alimentary tract. It is highly complex, requiring precise coordination of numerous nerves and muscles of the oral cavity, pharynx, larynx, and esophagus. Swallowing is integrated with other physiologic functions, including mastication and respiration. Impairments of swallowing may result from many different structural or physiologic disorders. Little is currently known about the direct effects of pollution on swallowing. Structures critical to swallowing, however, are vulnerable to damage by environmental hazards such as exposure to ionizing radiation or intake of toxins by ingestion or inhalation. The relationship of swallowing to environmental lung disease is an area of particular interest because impaired swallowing may result in aspiration of food particles into the lung, and because pollutants may hamper airway defense mechanisms. In this article, we discuss the possible impact of selected environmental agents on swallowing and suggest future directions for research.

Deglutition↗
PubMed1994

Update on Clostridium difficile-induced colitis, Part 2.

Clostridium difficile is a nosocomial pathogen able to survive unfavorable environments by sporulation; when conditions advantageous for rapid growth appear, the vegetative form is regenerated. Lack of conscientious hand washing and failure of health care providers to use disposable gloves facilitate transmission within institutions. Exposure to certain antimicrobials expedites C. difficile overgrowth within the colon by altering the composition of the normal gut microflora. Antineoplastic agents may also precipitate CDIC. The characteristics of the colonizing strain, the properties of the inciting drug, and individual host factors collectively seem to govern the expression of the disorder. Clinical presentations range from self-limiting diarrhea to severe diarrhea accompanied by abdominal pain, fever, and leukocytosis to potentially life-threatening PMC. A preponderance of data supports the interpretation that oral metronidazole and oral vancomycin are therapeutically equivalent for the treatment of all but the most severe cases of CDIC. Whether the two drugs are equivalent in severe CDIC is controversial and will probably remain so in the absence of a well-designed trial to expand on the findings of the study by Teasley et al. Because of the cost difference and therapeutic equivalence, oral metronidazole should be the preferred routine treatment for CDIC; oral vancomycin should be reserved for severe cases and cases that fail to respond to at least six days of oral metronidazole therapy. Another important argument, albeit a hypothetical one, for limiting institutional use of oral vancomycin is to minimize selective environmental pressure for the emergence and dissemination of vancomycin-resistant enterococci. An epidemic outbreak of CDIC caused by clindamycin-resistant C. difficile in an institution where clindamycin use was extremely high illustrates the possible consequences of such selective pressure. Oral metronidazole 250 mg four times daily will usually provide a satisfactory response, but clinicians may wish to consider increasing the total daily dose for some patients who have symptoms like fever and leukocytosis. For oral vancomycin, 125 mg four times daily is sufficient in virtually all circumstances. Ten days of therapy is usually adequate for either drug. CDIC in a patient unable to take medications orally presents a bit of a therapeutic dilemma. Two approaches that appear effective are rectal administration of vancomycin and intravenous administration of metronidazole, although intravenous metronidazole can fail to work, possibly because the colonic concentrations achieved are inadequate. Clinicians may wish to consider a total daily dose of intravenous metronidazole that is at the upper end of the adult dosage range, if this is feasible.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Oral↗
PubMed1997

Diabetes and hypertension in rodent models.

As shown by ourselves and others, animals models closely resembling human complex diseases like IDDM in BB/OK and hypertension in SHR/Mol rats can be used to dissect a complex disease into discrete genetic factors as has been done for hypertension in (BB/OK x SHR/Mol) cross hybrids. Discrete genetic factors, so-called QTLs, were detected on chromosomes 1, 10, 18, 20, and X. To gain additional information about the physiologic effect of the mapped blood pressure QTLs, genetically defined regions of the SHR rat were transferred onto the genetic background of diabetes-prone BB/OK rats. Four new congenic BB.SHR rats named BB.Sa, BB.Bp2, BB.1K, and BB.Xs were generated and characterized telemetrically for blood pressure, heart rate, and motor activity. The data demonstrate clearly that each single blood pressure QTL of the SHR rat causes a significant increase of the systolic blood pressure and has a different influence on diastolic blood pressure, heart rate, and motor activity. The effects were modified differently by the diabetic state in BB.Sa, BB.Bp2, and BB.Xs rats carrying all diabetogenic genes of the BB/OK rats. The results demonstrate that these newly established congenic strains are a unique tool to study the physiological control of blood pressure by a single blood pressure QTL on the one hand and their interaction with hyperglycemia on the other. It is well within the bounds of possibility that diabetic congenics reflect the diabetic hypertension seen in diabetic patients. Because of the synteny conservation in gene order between different mammals, genes of the appropriate human region could therefore be candidate genes for hypertension in diabetics. Furthermore, these congenic strains can also be used to study interactions between a blood pressure QTL and various selected environmental conditions. In this way, one could learn which QTL can be influenced by environmental factors and to what extent. Another point is the study of gene interactions. Because congenics are genetically identical except for the defined transferred region, congenics can be crossed to investigate the interaction between two or three blood pressure QTLs selected by the investigator and not by nature. These QTL combinations can be studied in the nondiabetic as well as diabetic state. Although the advantage of congenic strains has been shown, the transferred chromosomal regions are too large to pinpoint the gene responsible for the phenotypic change. Therefore, regions on each chromosome must be systematically whittled down, which can be done by crossing the congenics with BB/OK rats and intercrossing their progeny to generate recombinants. These can then be used for the creation of new congenic lines carrying a much smaller region of the SHR/Mol rat. This has been started for the region on chromosome 1 spanning a 16-cM region from the Sa to the Igf2 gene. BB.Sa rats were therefore backcrossed onto BB/OK rats and the resulting progeny were intercrossed. The aim will be to create at least three new congenic BB.Sa rat strains homozygous for the SHR alleles of Sa, Lsn, or Igf2 genes. However, new problems will emerge with these new congenics. To genetically define small regions requires more dense polymorphic markers than are currently available. Dense polymorphic markers will also be necessary to split the other regions on chromosomes 10, 18, 20, and X. We expect that in the near future it will be possible using this approach to define small regions of < 0.5 cM. The recent progress in gene mapping in the rat gives hope that the use of such congenic lines will allow the identification and recovery of the blood pressure genes in the near future.

Animals↗
PubMed1997

Serratia marcescens outbreak associated with extrinsic contamination of 1% chlorxylenol soap.

OBJECTIVES: To determine risk factors for Serratia marcescens infection or colonization, and to identify the source of the pathogen and factors facilitating its persistence in a neonatal intensive-care unit (NICU) during an outbreak. DESIGN: Retrospective case-control study; review of NICU infection control policies, soap use, and handwashing practices among healthcare workers (HCWs); and selected environmental cultures. SETTING: A university-affiliated tertiary-care hospital NICU. PATIENTS: All NICU infants with at least one positive culture for S marcescens during August 1994 to October 1995. Infants who did not develop S marcescens infection or colonization were selected randomly as controls. RESULTS: Thirty-two patients met the case definition. On multivariate analysis, independent risk factors for S marcescens infection or colonization were having very low birth weight (< 1,500 g), a patent ductus arteriosus, a mother with chorioamnionitis, or exposure to a single HCW. During January to July 1995, NICU HCWs carried their own bottles of 1% chlorxylenol soap, which often were left standing inverted in the NICU sink and work areas. Cultures of 16 (31%) of 52 samples of soap and 1 (8%) of 13 sinks yielded S marcescens. The 16 samples of soap all came from opened 4-oz bottles carried by HCWs. DNA banding patterns of case infant, HCW soap bottle, and sink isolates were identical. CONCLUSIONS: Extrinsically contaminated soap contributed to an outbreak of S marcescens infection. Very-low-birth-weight infants with multiple invasive procedures and exposures to certain HCWs were at greatest risk of S marcescens infection or colonization.

Anti-Infective Agents, Local↗