Variation in the hyphal growth rate and the virulence of two genotypes of the crayfish plague organism Aphanomyces astaci.

Crayfish plague, a devastating disease of freshwater crayfish, is caused by an oomycete organism, Aphanomyces astaci. Currently five genotypes of A. astaci are known, but variable features between the strains or genotypes have not been studied extensively. This study analysed 28 isolates of the As genotype and 25 isolates of the Ps1 genotype and reveals that the radial growth rate is significantly (P < 0.001) different between these two genotypes, although highly variable inside the genotype As. Two Ps1 genotype isolates and two As genotype isolates with different radial growth rates were tested in an infection trial. Clear differences were detected in the development of mortality in the test groups. The representatives of the Ps1 genotype caused total mortality within a short time span. The As genotype isolates were much less virulent. The slow-growing As isolate showed higher virulence than the As isolate with a high growth capacity. Although slow growth could be one survival strategy of the pathogen, several other mechanisms are involved in the pathogenicity and warrant further studies.

Distribution and epidemiology of genotypes of the crayfish plague agent Aphanomyces astaci from noble crayfish Astacus astacus in Finland.

The crayfish plague agent Aphanomyces astaci was isolated from 69 noble crayfish Astacus astacus samples in Finland between 1996 and 2006. All isolates were genotyped using randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). Altogether, 43 isolates belonged to the genotype group of Astacus strains (As), which is assumed to represent the genotype originally introduced into Europe around 1860 and into Finland in 1893. There were 26 crayfish plague isolates belonging to the group of Pacifastacus strain I (Ps1), which appeared in Europe after the stocking of the North American species signal crayfish Pacifastacus leniusculus. The geographical distribution of the 2 genotypes in Finland corresponded with the stocking strategies of signal crayfish. The majority of Ps1-strains (83%) were associated with a classical crayfish plague episode involving acute mortality, compared with only 33% of the As-strains. As-strains were found more often by searching for reasons for population declines or permanently weak populations, or through cage experiments in connection with reintroduction programmes. In some water bodies, isolations of the As-strains were made in successive years. This study shows that persistent crayfish plague infection is not uncommon in noble crayfish populations. The described epidemiological features suggest a difference in virulence between these 2 genotypes.

Evoked potential correlates of signal recognition between and within modalities.

Electrical responses evoked by clicks, flashes, changes in noise level, and changes in light level were recorded from the scalps of human subjects set to detect one of the stimuli. An early negative component of the evoked responses reflects selection between sensory modalities, whereas the later positive component reflects a more complex intramodal discrimination.

Controlled evaluation of a hospital-originated community transitional system.

The effect of a treatment program (E) providing inpatient care, a day hospital, community housing, and sheltered work are compared with a program (C) emphasizing rapid discharge. A group of 94 male general psychiatric patients were randomized to the two units. Outcome data collected at 18 months from admission revealed small but significant differences between the total samples in employment, maintenance of treatment contact, use of medication, and social adjustment. More C than E patients were in the hospital after the 14th month. Program effects varied considerably with patient type. Patients with less social disability had somewhat better employment outcomes with the E program, but no differences in use of services. Patients with a better prognosis by measure of psychopathology (Minnesota Multiphasic Personality Inventory cluster and diagnosis of schizophrenia) spent less inpatient time in the E program, but were not helped to better employment outcomes. Patients with greater social handicap were not differentially affected. More E patients than C with a poorer prognosis stayed in outpatient treatment and used antipsychotic medications. Patients in the E group with better previous employment and more social isolation used the E day hospital and community housing more heavily than other E subgroups.

Work disability among cancer patients.

To identify factors affecting the ability of persons with recent cancer diagnoses to remain in the labor force and retain premorbid levels of work performance, the investigators analyzed data on 247 individuals with lung, pancreatic, prostatic, or cervical cancer. Subjects were selected from a population-based tumor registry. According to Pearson correlations, ordinary least squares multiple regression, and logistic analysis, physical factors related to disease were the strongest predictors of work disability, defined as either leaving the labor force or functioning less fully at work than before becoming ill. The strongest predictors of work disability were physical dysfunction measured by the Sickness Impact Profile (SIP) and disease stage. Social background factors such as age, sex, income, and education were not statistically significant predictors. Two job characteristics, (1) physical demands of work and (2) discretion over hours worked and how much work would be done, predicted work disability, the latter appearing to help prevent this condition. Strictly disease-related factors appear more important here in predicting work disability than in studies of other diseases. Still, it appears that increasing flexibility of working hours and the pace of work could help some individuals with cancer histories remain in the labor force. Unwillingness of employers to facilitate such accommodation where technically feasible may constitute a form of discrimination against the cancer patient.

Relationships of admissions data and measurements of psychological constructs with psychomotor performance of dental technology students.

Abstract: The psychomotor skills required in dental laboratory technology and dentistry are similar. Dental educators have recognized the problems in selecting from among dental school applicants those with potential psychomotor skills. The purpose of this study was to examine the relationships of admissions data and measurements of psychological constructs of dental technology students with their psychomotor performance in first-semester dental laboratory courses. The dependent variables selected for the study were grades from three laboratory courses. Significant positive correlations (p<.05) were noted between all laboratory grades and previous college hours, previous college GPA, interview scores, field dependence-independence scores, block counting, trust, straightforwardness, and dutifulness. These data indicate that individual differentiation in learning ability, visual or spatial perception, and personality do affect psychomotor learning and should be taken into consideration in the design and execution of teaching and training curricula.

B.S. Education in Dental Laboratory Sciences at the University of Texas Health Science Center: an organizing framework.

This article describes the conceptual framework upon which the Bachelor's Degree program in Dental Laboratory Sciences at the University of Texas Health Science Center was constructed. Development of specific program objectives rested on the following four guiding principles: 1) combine professional laboratory training with management education; 2) focus on a problem-based pedagogy; 3) provide flexibility to accommodate today's "nontraditional" student population; and 4) utilize the close relationship with the University of Texas Dental School at San Antonio.

Molecular chaperones involved in protein degradation in the endoplasmic reticulum: quantitative interaction of the heat shock cognate protein BiP with partially folded immunoglobulin light chains that are degraded in the endoplasmic reticulum.

In the absence of immunoglobulin heavy-chain expression, some immunoglobulin light (L) chains are retained and degraded within the cell. We investigated the fate of two different nonsecreted murine L chains which exhibit different half-lives (50 min and 3-4 hr). Our results demonstrate that both nonsecreted L chains are quantitatively bound to BiP as partially oxidized molecules. The kinetics of L-chain degradation coincided with those of L-chain dissociation from BiP, which suggests that these two processes are functionally related. L-chain degradation does not depend on vesicular transport, indicating that these soluble proteins are degraded in the endoplasmic reticulum (ER). In contrast, secreted L chains, which interact only transiently with BiP, are completely oxidized and are not degraded even when they are artificially retained in the ER. Our data support the model that, by means of BiP interaction, the ER degradation mechanism has the potential to discriminate between partially and completely folded molecules.

Physical activity: its influence on nerve conduction velocity.

In a group of 40 healthy subjects, distal and proximal latencies of the median, tibial, and peroneal motor, and sural sensory nerves and their respective skin surface temperatures (Tsk) were measured before and after walking or bicycling. The baseline tests were performed 30 minutes after resting in a constant room temperature of 24C. The ambulation or bicycling task was continued for 30 minutes at a constant rate. Postactivity tests were performed within 30 minutes and between 45 to 60 minutes after termination of activity. Another test was done 75 to 90 minutes after bicycle exercise. After walking, there was a significant increase in Tsk in all lower extremity nerves tested (p less than 0.01). The increases were accompanied by faster distal and proximal latencies in both testing periods (p less than 0.01). Median nerve Tsk, distal and proximal latencies did not differ significantly from baseline values initially, but 45 minutes after walking Tsk was elevated and proximal latency had become faster (p less than 0.01). Following bicycling, lower extremity Tsk was significantly reduced over tibial, peroneal, and sural nerves by the third testing period (p less than 0.01) but only sural latencies were significantly prolonged (p less than 0.05) by this time. In the upper extremities median Tsk was significantly elevated and distal latency had become significantly faster 45 minutes after bicycling. Our data suggest that activity significantly influences nerve conduction latency results due to tissue temperature alteration. In addition, 30 minutes of rest after activity may not be sufficient time for the lower extremity temperatures to become stable.