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Biomedical subjects

T J Kneip

Publications and source records attributed to T J Kneip.

At least 19 recordsLinked to original sources
PubMed1985

Balbc/3T3 cell transformation response to extracts of organic air samples as seen by their survival in aggregate form.

Extracts of organic matter from samples of airborne particulate matter have been shown to possess components capable of transforming mammalian cells. This study was done to determine if Balbc/3T3 cells exposed to extracts of air samples could, unlike their normal counterparts, in the absence of a surface for attachment, divide on agar to form aggregates, and if these cells would demonstrate a dose-response phenomenon. Untreated and solvent treated control cells failed to form large aggregates and showed a decline in viable cell number over a 6-day period. Cells treated with either cyclohexane or acetone extracts of airborne particulate matter showed a dose-response increase in cell number along with the formation of progressively larger aggregates, findings similar to those seen with the positive, benzo[a]pyrene (BaP), control. Furthermore, these findings are in direct agreement with those in the simultaneously performed standard cell transformation assay which required 21 days to perform. Results show that survival in aggregate form is a rapid in vitro test system capable of detecting potentially carcinogenic activity in complex environmental mixtures.

Acetone↗
PubMed1983

N-nitroso compounds: evidence for their presence in airborne particles.

Chemical, infrared, and thermal energy analyses have provided evidence for the presence of the N-nitroso functional group in extracts of airborne particles. The total molar N-nitroso concentrations in New York City air are equivalent to the total concentrations of polycyclic aromatic hydrocarbons. Since 90 percent of the N-nitroso compounds that have been tested are carcinogens, the newly discovered but untested materials may represent a significant environmental hazard.

Air Pollutants↗
PubMed1979

Deposit and mobility of cadmium in a marsh-cove ecosystem and the relation to cadmium concentration in biota.

The study reported here presents the results of an investigation of a marsh-cove ecosystem heavily contaminated by cadmium. The most contaminated aquatic sediments were dredged in 1972-73, but the resuspension of the sediments and recycle of water from the dredge spoil resulted in reestablishment of a large contaminated sediment bed with concentrations very similar to those observed before dredging. The stability of the sediment concentrations and shallow depth of the cadmium in the sediments indicate that the deposit is relatively stable in agreement with the expectations based on the water chemistry of the system. Uptake does occur in both marsh and aquatic plants and all species of animals tested. Significantly elevated concentrations are observed compared to noncontaminated areas; however, edible portions of most fish do not appear to present a hazard. Crabs appear to present the most likely source of a hazard to humans. This potential hazard is still under investigation. The dredging removed about 5.5 MT of cadmium, about one-fourth of that originally estimated to be present, but twice that amount is found to be in the cove sediments 3 to 4 years after dredging. No appreciable improvement in the ecosystem has been made, and more careful consideration should be given to the need for decontamination and the method of removal of contaminated aquatic sediments in any future case.

Animals↗
PubMed1976

The effects of anemia on heme synthesis parameters during lead exposure.

The effects of anemia during lead exposures were studied using an infant baboon animal model. When the hemoglobin concentration was reduced to less than 70% of normal, a marked blood lead increase was observed and the free erythrocyte porphyrin value, aminolevulinic acid dehydratase activity and reticulocyte counts increased. Special emphasis should be placed on nutritional effects in lead exposures.

Anemia, Hypochromic↗
PubMed1975

Erythrocytic aminolevulinic acid dehydratase (ALAD) activity as a biologic parameter for determining exposures to lead.

The results of this work demonstrate that a significant exposure to one of several lead compounds can be detected by the ALAD test without a concomitant rapid increase in blood lead concentration. Use of the ALAD test may effectively demonstrate the occurrence of excessive exposure at an earlier time than possible by the accepted blood or urine lead concentration measures. By comparing "early" and "steady state" values of PbB and ALAD, it was possible to derive an equation which can be used to determine an ultimate (steady state) value of PbB from an early (short-term) ALAD measurement. Re-examination of workplace atmospheres would be indicated by findings of depressed ALAD activity in the absence of elevated blood lead values. This could occur when sporadic lead exposures are occurring or upon initiation of a period of continuing elevated exposures. Thus, corrective action can be requested and taken prior to the point at which an excessive blood lead value would be found. Further studies of industrial groups are indicated to confirm the usefulness of the test for the purposes suggested.

Acetates↗