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Biomedical subjects

S Bauer

Publications and source records attributed to S Bauer.

283 records · Page 16Linked to original sources
PubMedDate not supplied

Comparison of dextranases for their possible use in eliminating dental plaque.

Dextranases produced by P lilacinum NRRL 896 and NRRL 895 and by P funiculosum NRRL 1768 were studied for their possible incorporation into a dental plaque elimination system. The following properties of the enzymes were compared: effect of the pH level on the activity and the stability of the enzymes on the acid side of the pH range; molecular weight; affinity to Sephadex G-25 which served as a model for insoluble dextran in plaques; and the extent of hydrolytic action on dextrans containing alpha-1,3, alpha-1,4 and alpha-1,6 bonds in various proportions. The enzyme of P funiculosum NRRL 1768 certainly has its limitations as a plaque-degrading enzyme, for example, diminished activity at a high pH level and lack of activity on alpha-1,3 bonds. However, from our studies, and from a survey of the relevant literature with respect to the aforementioned properties in other dextranases, the enzyme of P funiculosum NRRL 1768 emerges as a suitable choice for incorporation as dextranase, possibly together with other enzymes, into an enzymatic dental plaque elimination system.

Chemical Phenomena↗
PubMedDate not supplied

Toxicological investigations in the semiconductor industry: I. Studies on the acute oral toxicity of a complex mixture of waste products from the aluminium plasma etching process.

In dry etching processes--one of the sources of potential exposure to toxic wastes in the semiconductor industry--complex mixtures of inorganic and organic compounds arise from reactions between feed stock gases (BCl3/Cl2), top layers (aluminium photoresist), and the carrier gas (N2). Two different fractions of the complex mixture--one an ethanolic solution (ES) and the other an insoluble liquid residue (LR)--were examined for acute oral toxicity in rats. Analytical data showed that the ethanol soluble fraction contained mainly inorganic compounds, whereas the residue contained various halogenated hydrocarbons. Neither death nor behavioral changes occurred after oral administration and observation up to 23 days. ES caused a lower mean arterial blood pressure in both sexes, increased P-R-intervals in male rats, and caused some mild biochemical and hematological alterations and changes in relative organ weights compared to the control groups. Exposure to LR influenced food and water intake, and caused a significant decrease in body weights, signs of polyurie, as well as changes in various relative organ weights and biochemical and hematological parameters. The blood pressure of the male animals fell and the heart rates of both sexes decreased.

Aluminum↗
PubMedDate not supplied

Toxicological investigations in the semiconductor industry: III: Studies on prenatal toxicity caused by waste products from aluminum plasma etching processes.

The prenatal toxic effects of contaminated vacuum pump oil (Sample A) and solid waste products (Samples B and C) originating from aluminum plasma etching processes in semiconductor manufacturing were investigated. Three strains of pregnant mice with different degrees of sensitivity during organogenesis (days 6-15 of gestation) were treated daily with 1000 mglkg b.w. (Sample A), 500 or 750 mg/kg b.w. (Sample B), and 250, 500, or 750 mg/kg b.w. (Sample C). On day 18 of pregnancy, the animals were killed and examined for gross changes, number and weight of live fetuses, as well as the number of postimplantation losses and malformations. Analytical data showed that the investigated wastes contained various halogenated hydrocarbons and inorganic compounds. Sample A revealed no signs of prenatal toxic action. In contrast, administration of Samples B and C caused strong prenatal toxic effects. The number of live fetuses declined in a dose--related manner, and evidence of intrauterine growth retardation was noted in fetuses that survived to day 18. The number of fetuses with malformations (only cleft palates) rose significantly in accordance with the doses and sensitivity of the strains (> 95 % of the fetuses of the most sensitive strain after 750 mg/kg; 85% after 500 mg/kg).

Aluminum↗
PubMedDate not supplied

Toxicological investigations in the semiconductor industry: IV. Studies on the subchronic oral toxicity and genotoxicity of vacuum pump oils contaminated by waste products from aluminum plasma etching processes.

Dry etching processes in semiconductor manufacturing use ionized gases in closed reactors at pressures below 1 torr. Vacuum pump systems that service the reaction chambers are potential sources of exposure to complex mixtures of inorganic and organic compounds. These mixtures consist of unused process gases and process by-products that condense and accumulate in the vacuum pump oils. To evaluate potential hazards of dry etch vacuum equipment, a contaminated vacuum pump oil sample from a BCl3/Cl2 etching process was analyzed. The waste oil was administered by gavage for 14 or 28 days to male and female Wistar rats. Neither death nor behavioral changes occurred after subchronic treatment or during a 14-day posttreatment period. Only slight effects on body weights, clinical chemistry, and hematology data were seen in the exposed animals, although the livers of all waste oil-exposed rats of both sexes showed remarkable hypertrophic degenerations. Genotoxicological investigations were performed through the Ames assay (Salmonella assay) and the Micronucleus assay. The contaminated oil sample caused clear genotoxic effects in both test systems.

Administration, Oral↗
PubMedDate not supplied

Effect of position (semirecumbent versus supine) on postoperative oxygenation in markedly obese subjects.

In 22 markedly obese, otherwise healthy, women studied postoperatively on each of days 1 through 3 after intra-abdominal operation, the effect of position change on arterial oxygenation was assessed. There was a statistically significant decrease in PaO2, an increase in A-aDO2 and a simultaneous modest reduction in PaCO2 with the assumption of the supine position on postoperative days 1 and 2, but not positional difference demonstrable in any studied variable by day 3. This report suggests that during the first 48 hours after abdominal surgery in obese patients, assumption and maintenance of the semirecumbent posture is a valuable therapeutic modality to improve arterial oxygenation.

Abdomen↗
PubMedDate not supplied

Production of pro- and anti-inflammatory cytokines of human placental trophoblasts in response to pathogenic bacteria.

OBJECTIVE: We studied the production of cytokines in purified cultures of human term trophoblasts in the presence of pathogenic strains of Escherichia coli, Bacteroides fragilis, Mycoplasma hominis, Staphylococcus aureus, and Streptococcus agalactiae, which have been identified in intrauterine infections. METHODS: Human villous trophoblasts were isolated from term placentas after cesarean section and purified by several steps. After 6, 12, and 24 hours of incubation with the different heat-inactivated bacteria, interleukin-1beta (IL-1beta), interleukin-6 (IL-6), interleukin-8 (IL-8), and interleukin-10 (IL-10) as well as tumor necrosis factor-alpha (TNF-alpha) were measured from supernatants by commercially available enzyme-linked immunosorbent assay. Expression of cytokine mRNAs was determined by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: In nonstimulated cultures, low (IL-1beta and TNF-alpha) and high (IL-6, IL-8, and IL-10) basal secretion of cytokines was detectable. The pathogenic microorganisms induced a dose- and time-dependent release of IL-1beta, IL-6, IL-8, and IL-10, whereas TNF-alpha secretion was not elevated. E coli was the most potent inducer followed by B fragilis, S agalactiae, S aureus, and M hominis. Transcripts encoding IL-1beta, IL-6, IL-8, or IL-10 were elevated in the RT-PCR reactions, suggesting that transcriptional mechanisms contribute to elevated cytokine expression. CONCLUSION: Pathogenic microorganisms stimulated mRNA expression and polypeptide release of pro- and anti-inflammatory cytokines from placental trophoblasts. Induction of both inflammation-promoting and inflammation-inhibiting cytokines by bacterial products could play a role in modulating the inflammatory response associated with chorioamnionitis.

Bacterial Infections↗
PubMedDate not supplied

Identification of carcinoma cells in ascitic and pleural fluid. Comparison of four panepithelial antigens with carcinoembryonic antigen.

The cell membrane antigens epithelial membrane antigen (EMA), epithelial glycoprotein 34, (egp34), BW-495 and tumor-associated antigen 72 (TAG-72) are present in most benign and malignant epithelial cells and can be demonstrated with the help of monoclonal antibodies. In a study on the identification of carcinoma cells in samples of ascitic and pleural fluid involving 170 patients, we compared the value of immunocytochemical labeling of these antigens with that of immunocytochemical demonstration of carcinoembryonic antigen (CEA). Antibodies to EMA and egp34 occasionally also reacted with reactively proliferating mesothelial cells in benign conditions and thus appear to be inappropriate for diagnostic use. Cells positive for BW-495, TAG-72 and CEA, however, have never been found in benign conditions; the specificity of these antigens thus permits their use in diagnosis. Antigen-expressing cells were found in 85% (BW-495), 62% (TAG-72) and 60% (CEA) of cytologically positive samples from carcinoma patients. Similarly, positive reactions for BW-495, TAG-72 and CEA were observed in, respectively, 36%, 29% and 34% of cytologically negative or suspicious samples. BW-495 thus appears to be a suitable marker for the demonstration of carcinoma cells in samples of pleural and ascitic fluid and to have a higher degree of sensitivity than does either TAG-72 or CEA.

Antigens, Neoplasm↗
PubMedDate not supplied

Esophagus cancer and radiation exposure due to nuclear test fallout: an analysis based on the data of the Semipalatinsk historical cohort, 1960-1999.

This paper describes the Semipalatinsk historical cohort study and, in particular, examines the association between combined external and internal radiation exposure and esophagus cancer. Esophagus cancer is the most frequent single cancer site in the cause of death follow-up for the Semipalatinsk cohort. Set up in the 1960s, this historical cohort included 10 exposed settlements in the vicinity of the Semipalatinsk nuclear test site in East Kazakhstan as well as 6 comparison settlements in a low exposure area of the same region. The external and internal radiation doses to the population of the settlements under study were mainly due to local fallout from atmospheric nuclear testing (1949-1962). The database includes dosimetry and health information for 19.545 inhabitants of exposed and comparison villages in the Semipalatinsk region, comprising a total of 582.750 person-years of follow-up between 1960 and 1999. Cumulative effective dose estimates in this cohort range from 20 mSv to -4 Sv, with a mean dose of 634 mSv in the exposed group. Relative risks were calculated in terms of rate ratios, using a Poisson regression model for grouped person-time data. Esophagus cancer was found substantially elevated, with a statistically significant increase of the relative risk with dose and an ERR/Sv of 2.37 (1.45; 3.28) for the total cohort. If the data set was restricted to the exposed group only, the ERR/Sv was found considerably lower (0.18 (-0.16; 0.52)), whereas the dose-response remained significant only in women. Overall, our results based on the Semipalatinsk historical cohort indicate an association between fallout exposure and the risk of esophagus cancer that should be further investigated.

Adult↗
PubMedDate not supplied

[Music therapy single case process research--development and organization of a research field].

Music therapy yet to be discovered as a target of psychotherapy research. A first step consists in creating adequate samples of significant musical dialogues. Video-recording is an essential requirement for establishing such data. To test the clinical view that the emotional content of the musical dialogue in music therapy reflects the basic relationship issues of a patient was the objective of this study. By using ratings of significant musical dialogue sequences with the instrument of semantic differential comparing groups with varying clinical expertise (music therapists, psychoanalyts, lay persons) the results demonstrate that there is considerable stability of the judgments; however, systematic differences exists among the three groups of raters.

Adult↗
PubMedDate not supplied

Toxicological investigations in the semiconductor industry: II. Studies on the subacute inhalation toxicity and genotoxicity of gaseous waste products from the aluminum plasma etching process.

Male and female Wistar rats were exposed to waste gas arising from a plasma etching process in the semiconductor industries for six hr per day, five days per week, for four weeks in order to characterize subacute organ toxicity and genotoxicity. The waste gas was a complex mixture of different chlorinated hydrocarbons, inorganic by-products, and unused process gases, diluted by room air. Neither death nor behavioral changes occurred after subacute exposure. No significant exposure-related effects on body weight gain, hematology, or cardiovascular parameters were observed. Only slight effects on organ weights and clinical chemistry were seen in the exposed animals. The exposed rats of both sexes showed statistically significant increases in chromosomal aberrations and sister chromatid exchanges in bone marrow cells.

Administration, Inhalation↗
PubMedDate not supplied

[Environment, patient information, and organization in a pediatrics urodynamics unit].

OBJECTIVES: Urodynamic studies require patient cooperation, and this can be difficult in the pediatric age due to their invasive nature. Our aim was to assess the benefits of organization, facility design and information specifically adapted to children. METHODS: We describe the facility design and organization of the Urodynamics Unit at the Children's Hospital in Boston. Environmental factors are adapted to the pediatric age and aim to reduce the impact of the examination. There are child's objects, images and toys in the examining room. Parents are allowed to be in the room while the test is performed, and music is played during the procedure. We describe the information pattern and the behavior of the nurses and physicians to preserve the child's privacy. An information leaflet and a survey on symptoms is sent to parents before the test. Information is adapted to every age and aims to reduce parental anxiety towards the test and make them understand the need for the study. There are two premises for information: 1) every procedure will be explained to the child and parents, and 2) they will be told the truth. RESULTS: An enhanced cooperation has been noted following these guidelines. Between 5 and 8% of the studies performed are not evaluable due to lack of cooperation from the patient and only two children have totally refused the test in the last two years (0.2%). CONCLUSIONS: Cooperation among urologists and specialized nurses as well as attention towards the child's and parents' psychological factors can enhance the diagnostic yield of this test.

Adolescent↗
PubMedDate not supplied

Circulatory assist techniques after cardiomyoplasty. Determinants for clinical outcome and later consequences.

Cardiomyoplasty, in spite of recent improvements, remains a high risk operation. The early postoperative period is sometimes very critical, even for patients selected from preoperative New York Heart Association functional class IV. During the surgical period, poor hemodynamics may be responsible for early death, as well as influence latissimus dorsi muscle long-term viability. Circulatory assist, including pharmacologic support with enoximone, intraaortic balloon counterpulsation (IABP), and ventricular assist devices (VAD), may be needed. From February, 1993 to September, 1994, 14 clinical dynamic cardiomyoplasty procedures were performed using the Medtronic (Minneapolis, MN) system at Hôpital La Timone, Marseille, France. Eight patients suffered from early and severe postoperative heart failure. Enoximone was used in three patients and IABP in five patients. Two days after cardiomyoplasty, one of the IABP patients required an implantable left VAD (Thermocardio Systems, Woburn, MA) as a bridge to cardiac transplantation. Overall hospital mortality was 7%. The authors studied the preoperative clinical data and surgical techniques to find specific risk factors that could have influenced postoperative events. Another aim of this study was to evaluate long-term benefits in these particular patients. Results showed that cardiomyoplasty patients may require complex means to overcome postoperative hemodynamic failure, but without necessarily poor long-term results. This should be an important step in improving future patient selection.

Adult↗