Nutrient loading impacts on culturable E. coli and other heterotrophic bacteria fate in simulated stream mesocosms.

Understanding fecal indicator bacteria persistence in aquatic environments is important when making management decisions to improve instream water quality. Routinely, bacteria fate and transport models that rely on published kinetic decay constants are used to inform such decision making but may not adequately represent instream conditions. The objective of this work was to evaluate bacterial responses to applied nutrient amendments and provide additional information regarding bacterial response to applied changes that can be incorporated into future modeling efforts. Re-created stream mesocosms were established in laboratory-based, repurposed algae raceways filled with water and sediment from a small, 3rd order Southeast Texas stream. Mesocosm treatments consisted of low (10x) or high (50x) nutrient doses above ambient water concentrations operated at low (0.032 m/s) or high (0.141 m/s) flow rates. Escherichia coli and heterotrophic bacterial concentrations were quantified in water and sediment over 22 days. No significant differences in kinetic constants were observed among E. coli in water or sediment, and only E. coli in sediment showed any growth response. Heterotrophic plate counts revealed a pronounced growth response in water and sediment within 24 h of nutrient addition but did not differ significantly from control mesocosms. Significant kinetic constant differences between E. coli and heterotrophic bacteria in water were identified (p < 0.01) but did not differ significantly in sediment (p > 0.48). Results indicate that nutrient addition does affect microbial numbers instream, but competition from heterotrophic bacteria may prevent an E. coli growth response.

Assessing genetic heterogeneity in production cell lines: detection by peptide mapping of a low level Tyr to Gln sequence variant in a recombinant antibody.

A recombinant antibody directed against the human epidermal growth factor receptor-2 extracellular domain was subjected to detailed structural characterization. Heterogeneity in the heavy chain was demonstrated by recovery of two forms of a tryptic peptide, with either glutamine or the expected tyrosine at residue 376. Subsequent experiments indicated that the Y376Q variant developed during transfection of the antibody heavy and light chain genes into Chinese hamster ovary cells. Levels of the Y376Q variant (range: 27% to 1%) in the purified antibody were inversely proportional to cell age. The established cell line was subcloned and found to be heterogeneous by polymerase chain reaction analysis of cell extracts and protein analysis of the purified antibody. Ten percent of subclones produced high levels of the Y376Q variant while 90% of the subclones produced antibody with only the expected heavy chain sequence. This report demonstrates the utility of peptide mapping as a sensitive tool for assessing genetic heterogeneity of recombinant cell lines.

Glycosylation pattern and disulfide assignments of recombinant human differentiation-stimulating factor.

This report describes the post-translational modifications of recombinant human differentiation-stimulating factor, a 180-residue glycoprotein that is secreted from transfected Chinese hamster ovary cells. Peptide peptides containing six potential N-glycosylation sites were analyzed to determine that Asn residues 9, 34, 63, 73, 96, and 116 were utilized. Additional peptides, generated by tryptic digestion of peptic fragments, allowed the assignments of three intrachain disulfide bonds (Cys-18 to Cys-131, Cys-12 to Cys-134, and Cys-60 to Cys-163).

Structural characterization of a recombinant CD4-IgG hybrid molecule.

CD4-IgG is a homodimer of a hybrid polypeptide consisting of the two amino-terminal domains (residues 1-180) of human CD4 fused to the hinge region and the second and third constant-sequence (CH2 and CH3) Fc domains (residues 216-441) of human immunoglobulin G (IgG-1). This antibody-like molecule, termed an immunoadhesin, was produced in an effort to combine the binding specificity of CD4 with several potentially desirable properties of IgG molecules [Capon et al. (1989) Nature 337, 525-531]. The structural characteristics of the molecule have been evaluated to demonstrate that CD4-IgG has the same features as the N-terminal region of soluble CD4, while retaining those expected for the Fc portion of human IgG. Identification of peptides recovered from the tryptic map confirmed 98.8% of the expected structure of CD4-IgG. The detection of glucosamine in peptides containing Asn257 and the retention time shift of this tryptic peptide after deglycosylation confirmed the presence of Asn-linked oligosaccharides at this position. Four pairs of intrachain and two interchain disulfide bonds were also established.

Acute responses to experimental blunt head trauma: topography of white matter edema.

The location of edema and territory of extravasation of serum protein were examined in the white matter of cats with different forms of intracranial pathology following an impact-acceleration injury to the head. Edema was tested with an organic density gradient and Evans blue dye was used as a marker for breakdown of the blood-brain barrier. Animals with tissue hemorrhage (contusions) involving both cerebral cortex and white matter had a substantial, progressive accumulation of Evans blue-stained edema near tissue hemorrhage during the 6 h following trauma. In addition, this category of cats had a widespread, mild edema at 15 min after injury that was usually unaccompanied by Evans blue stain. Cats with cortical contusions had rather mild edema neighboring tissue hemorrhage; animals with subarachnoid hemorrhage in the absence of cerebral contusions had neither measurable edema nor (usually) visible Evans blue staining. We conclude that: acute traumatic cerebral edema varies considerably in presence, magnitude and territory with different forms of intracranial pathology; and mechanically induced edema can occur that is independent of spread of fluid from areas of tissue hemorrhage.

The unusual karyotype of the lesser kudu, Tragelaphus imberbis.

The chromosome set of the lesser kudu, Tragelaphus imberbis, consists of 38 elements in both sexes. In contrast to most other members of the bovid subfamily Tragelaphinae, both the X and the Y chromosomes are compound, having fused with identical autosomes from ancestors presumed to have higher chromosome numbers. From a comparison of the unusual sex chromosomal rearrangements that have occurred in this family, a hypothetical lineage has been derived. This family tree and the details of various banding studies in the lesser kudu are described.

[Prevention of thromboembolism with heparin in gynecological and obstetric surgery]. / Thromboembolie-Prophylaxe mit Heparin bei gynäkologischen und geburtshilflichen Operationen.

During a period of 28 months 983 gynaecological patients had major abdominal or vaginal operations under Heparin prophylaxis. In no case thrombosis or pulmonary embolism occurred. 5 hemorrhages required surgical revision and temporary reduction of Heparin dose. Global tests for preoperative diagnosis of hemostasis and for postoperative control of Heparin effect are discussed. Possible reactive fibrinolysis under Heparin administration, its complications and control are mentioned. Peri- and postoperative prophylaxis of thrombo-embolism with Heparin in daily dosages up to 20,00 I.U. seems well suitable.

[Complications of pregnancy in female anesthesiologists (author's transl)]. / Schwangerschaftskomplikationen bei Anästhesistinnen

A questionnaire was sent out to the members of the German Society of Anesthesiology and Reanimation with the purpose to clarify whether there is an increased incidence of certain complications during pregnancy among anesthesiologists. The results obtained allow the tentative conclusion that there is a higher abortion rate. There was also an increase of premature deliveries and congenital malformations. Surprisingly, a significant increase in births of females was observed among female anesthesiologists (with or without exposure) and among the offspring of male anesthesiologists (with or without exposure). Therefore this observation cannot be related to the exposure in operating rooms. On the basis of these results and reports from literature it is not permissible to relate the incidence of these complications exclusively to the chronic inhalation of narcotic gases. Other covariables which might cause the complications were not considered in this study. Nevertheless in spite of these limitations narcotic gases should be removed from the atmosphere of operating theatres as completely as possible.