Investigating the effect of forestry on leaf-litter arthropods (Algonquin Park, Ontario, Canada)

Arthropods are the most diverse taxonomic group of terrestrial eukaryotes and are sensitive to physical alterations in their environment such as those caused by forestry. With their enormous diversity and physical omnipresence, arthropods could be powerful indicators of the effects of disturbance following forestry. When arthropods have been used to measure the effects of disturbance, the total diversity of some groups is often found to increase following forestry. However, these findings are frequently derived using a coarse taxonomic grain (family or order) to accommodate for various taxonomic impediments (including cryptic diversity and poorly resourced taxonomists). Our intent with this work was to determine the diversity of arthropods in and around Algonquin Park, and how this diversity was influenced by disturbance (in this case, forestry within the past 25 years). We used DNA barcode-derived diversity estimates (Barcode Index Number (BIN) richness) to avoid taxonomic impediments and as a source of genetic information with which we could conduct phylogenetic estimates of diversity (PD). Diversity patterns elucidated with PD are often, but not always congruent with taxonomic estimates-and departures from these expectations can help clarify disturbance effects that are hidden from richness studies alone. We found that BIN richness and PD were greater in disturbed (forested) areas, however when we controlled for the expected relationship between PD and BIN richness, we found that cut sites contained less PD than expected and that this diversity was more phylogenetically clustered than would be predicted by taxonomic richness. While disturbance may cause an evident increase in diversity, this diversity may not reflect the full evolutionary history of the assemblage within that area and thus a subtle effect of disturbance can be found decades following forestry.

A phase II study of G17DT in gastric carcinoma

PURPOSE

G17DT is a gastrin immunogen, raising antibodies that blockade gastrin-stimulated growth. The aim of the study was to characterise antibody response and assess safety and tolerability of G17DT given to patients with gastric cancer.

EXPERIMENTAL DESIGN

G17DT was administered to 52 patients with gastric adenocarcinoma at weeks 0, 2 and 6 by intramuscular injection at doses of 10, 100 and 250 microg. Antibody levels were measured by an ELISA assay. A radioligand displacement assay determined the ability of G17DT-immunised patients' sera to inhibit binding of 125IG17 to cholecystokinin (CCK)-2 receptors.

RESULTS

By week 12 of the study, 6/12 evaluable stage I-III patients achieved an antibody response in the 10 microg group, 7/11 in the 100 microg group, and 11/12 in the 250 microg group. Stage IV patients dosed at 250 microg achieved a similar response rate to stage I-III patients dosed at 10 or 100 microg. G17DT was well tolerated in 47/52 patients. Two patients suffered significant adverse reactions including injection site pain and abscess. G17DT antibodies displaced iodinated gastrin from CCK-2 receptors, with the level of displacement correlating with antibody titre.

CONCLUSIONS

G17DT immunisation is a well-tolerated method of raising functional antibodies to 17 amino acid gastrin forms in patients with gastric carcinomas.

Risk as feelings

Virtually all current theories of choice under risk or uncertainty are cognitive and consequentialist. They assume that people assess the desirability and likelihood of possible outcomes of choice alternatives and integrate this information through some type of expectation-based calculus to arrive at a decision. The authors propose an alternative theoretical perspective, the risk-as-feelings hypothesis, that highlights the role of affect experienced at the moment of decision making. Drawing on research from clinical, physiological, and other subfields of psychology, they show that emotional reactions to risky situations often diverge from cognitive assessments of those risks. When such divergence occurs, emotional reactions often drive behavior. The risk-as-feelings hypothesis is shown to explain a wide range of phenomena that have resisted interpretation in cognitive-consequentialist terms.

Researching the rural-metropolitan health differential using the 'social determinants of health'

Recent research indicates that the health status of rural people is inferior to that of people living in metropolitan Australia. This paper summarises the rural-metropolitan health differential and turns to the field of research being called the social determinants of health for explanations of rural health inequalities. The paper explores the ways in which psychosocial factors can interact with material, behavioural and sociocultural factors to contribute to health outcomes. It suggests that the concepts of place and rurality may be useful in future research on the determinants of population health. Further research issues are identified that need to be addressed if we are to understand the complexities of rural health disadvantage.

Effects of beta 6 aromatic amino acids on polymerization and solubility of recombinant hemoglobins made in yeast

Valine, leucine, tryptophan, and phenylalanine substitutions at the beta 6 position of hemoglobin (Hb) were made using a yeast expression system coupled with a polymerase chain reaction-based mutagenesis strategy. The oxygen affinity and absorption spectra of these mutants were similar to recombinant Hb A except for Hb beta E6W which had a higher absorbance at approximately 280 nm. The deoxy forms of Hb beta E6L and Hb S showed characteristic delay times prior to polymerization. Tetrameric deoxy-Hbs containing tryptophan or phenylalanine at the beta 6 position had higher solubilities and polymerized less readily compared with deoxy-Hb S. However, when oversaturated, these Hbs polymerized without a delay time. These results suggest that Hb beta E6W and Hb beta E6F form polymers upon deoxygenation by a linear polymerization mechanism without nuclei formation. During polymerization, bulky hydrophobic amino acids, like phenylalanine and tryptophan at the beta 6 position, might interact with the acceptor pocket on the surface of an adjacent Hb molecule but may not be able to form stable hydrophobic interactions like beta 6 valine and leucine. Difficulty in insertion of the bulky side chains of these aromatic amino acids into the hydrophobic acceptor pocket on an adjacent tetramer may inhibit nuclei formation prior to polymerization.

Management of Plant-parasitic Nematodes with a Chitin-Urea Soil Amendment and Other Materials

Field trials were conducted with a chitin-urea soil amendment and several other nematicides on four crop-nematode combinations: tomato-Meloidogyne incognita; potato-Meloidogyne chitwoodi; walnut-Pratylenchus vulnus; and brussels sprouts-Heterodera schachtii. Significant (P </= 0.10) nematode population reductions were obtained with the chitin-urea soil amendment in the trims on potato and walnut. In the trials on brussels sprouts and on tomato, phytotoxicity occurred at rates of 1,868 and 1,093 kg/ha, respectively. Significant (P </= 0.10) nematode reductions were also obtained with metham sodium on potato; with 1,3-D on tomato and brussels sprouts; and with sodium tetrathiocarbonate, XRM 5053, fenamiphos, ethoprop, LX1075-05, LX1075-07, and SN 109106 on tomato. The following materials did not provide significant nematode control under the conditions of the particular experiments: metham sodium, oxamyl, and Yucca extract on tomato; and dazomet granules on brussels sprouts.

Gallstones in the peritoneal cavity. A clinical and experimental study

Gallstones are commonly lost into the peritoneal cavity during cholecystectomy. We investigated the effect of this occurrence using a rabbit model and also by a postal questionnaire of patients in whom gallstones were lost at the time of laparoscopic cholecystectomy. No deleterious effects could be demonstrated, and it is concluded that there is no indication for a laparotomy to retrieve "escaped" gallstones during laparoscopic cholecystectomy.

Domiciliary and out-patient treatment of self-poisoning patients by medical and non-medical staff

In a study of domiciliary and out-patient treatment of self-poisoning patients, using a brief problem-orientated approach, it was found that domiciliary treatment resulted in much higher attendance rates but no difference in outcome. Patients who completed out-patient treatment had a better outcome than those who failed to attend treatment sessions. Completion of out-patient treatment was more frequent among higher social class patients. Domiciliary treatment may be more appropriate in some cases for married patients and for those of lower social class. Medical and non-medical staff proved to be equally effective therapists. Future research should be concerned with evaluation of alternative methods of provision of help and further identification of patients who are most likely to benefit from treatment.