Stem cell function during plant vascular development.

While many regulatory mechanisms controlling the development and function of root and shoot apical meristems have been revealed, our knowledge of similar processes in lateral meristems, including the vascular cambium, is still limited. Our understanding of even the anatomy and development of lateral meristems (procambium or vascular cambium) is still relatively incomplete, let alone their genetic regulation. Research into this particular tissue type has been mostly hindered by a lack of suitable molecular markers, as well as the fact that thus far very few mutants affecting plant secondary development have been described. The development of suitable molecular markers is a high priority in order to help define the anatomy, especially the location and identity of cambial stem cells and the developmental phases and molecular regulatory mechanisms of the cambial zone. To date, most of the advances have been obtained by studying the role of the major plant hormones in vascular development. Thus far auxin, cytokinin, gibberellin and ethylene have been implicated in regulating the maintenance and activity of cambial stem cells; the most logical question in research would be how these hormones interact during the various phases of cambial development.

Psychosocial work factors and dementia.

AIMS: To evaluate the association between psychosocial workplace factors and dementia in a case-control study. METHODS: Patients with dementia (aged 55-99 years) were recruited from 23 general practices in the city of Frankfurt-on-Main and surrounding area in 1998-2000. Of these, 108 were suffering from possible Alzheimer's disease, 59 from possible vascular dementia, and 28 from secondary or unclassified dementia. A total of 229 control subjects (aged 60-94 years) was recruited from the same study region: 122 population controls and 107 dementia-free ambulatory patients. A detailed job history was elicited in a structured personal interview (next-of-kin interviews of cases). Psychosocial work exposure was assigned to cases and control subjects by linking lifetime job histories with a Finnish job-exposure matrix. Data were analysed using logistic regression, to control for age, region, sex, dementia in parents, education, smoking, and the psychosocial network at age 30. RESULTS: There were decreased odds ratios for high challenge at work, high control possibilities at work, and high social demands at work. High risks for error at work revealed a significant positive association with the diagnosis of dementia. Restriction of the analysis to cases with possible Alzheimer's disease or to cases with possible vascular dementia led to similar results. CONCLUSIONS: These results support a role for psychosocial work factors in the aetiology of dementia. As an alternative explanation, people might have chosen jobs with poor work factors due to preclinical dementia, which becomes clinically manifest decades later.

Efforts of health promotion teams to improve the psychosocial work environment.

This study evaluated the actions of 12 departmental "health promotion teams" and the means they used to improve the psychosocial work environment of a metal factory in a 3-year project. The teams included 80 members and were supported by organizational psychologists twice a year. A survey feedback process was applied in the beginning among all 773 employees, including management (response rate 94%). At the end, a questionnaire on perceived changes was filled out (response rate 94%). The teams guided the developmental process and initiated various activities in cooperation with the personnel. The planned activities were mainly directed at improving physical fitness and social climate. The majority of the personnel participated in these activities and were satisfied with them.

Applicability of survey feedback for an occupational health method in stress management.

The main stressors in work organizations have been determined in the research on mental stress. This has prompted occupational health personnel to actively look for new tools in reducing stress. However, only a few workplaces have implemented action models for health promotion by reducing stressors. The aim of this project was to investigate the applicability of survey feedback for an occupational health method of stress management. The survey feedback process, which has been one of the main approaches in organization development, was applied for stressor reduction. The employee's commitment to the programme was confirmed by participation. The occupational health personnel were responsible for carrying out the programme. The project was carried out in selected departments of one factory of an international paper company. On the basis of the survey feedback, the departments made changes in their action models, environment and instruction and guidance systems. According to the follow-up in one department, the variability of work increased, and overall mental and physical strenousness decreased. The OH personnel shifted their working model towards more active co-operation with the work units. Today the survey feedback is a routine method of the occupational health service of the company.

Acid-base chemistry of vitamin B6 compounds in methanol.

The enzymatic reactions involving pyridoxal 5'-phosphate (PLP) can be simulated in solutions; thus, this system forms a favorable model for understanding the requirements of the enzymatic catalysis. We have studied in methanol protonic equilibria of the imines formed between PLP or salicylaldehyde (SA) and various amino acids, using UV and NMR spectroscopy. A glass electrode and an operational pH* scale were used to control acidity. The first protonation of the phosphate of PLP imines can be detected by UV spectroscopy with pK* at 10.8, proved by [31P]-NMR. The second protonation of phosphate (pK* at 4.8) is accompanied by increased hydrolysis of the imines. The imines of aspartate deviate from the imines of nondicarboxylic amino acids indicating that the beta-carboxyl of aspartate is internally hydrogen-bonded. PLP-2-aminobutanol Schiff base does not show with [1H]-NMR at pH* 7 separate peaks for ketoenamine-enolimine tautomers even at -90 degrees C, SA-phenylalanine shows an unidentified absorption at 350-380 nm. This was tentatively assigned a trans structure.

Health and stress of seafarers.

The perceived health and stress of seafarers was studied in relation to work stressors and personality characteristics (self concept). The data were collected with a questionnaire. The study group consisted of 591 seafarers representing different occupations of the Finnish merchant fleet. Forty percent of the respondents sailed in ocean traffic, 31% on the Baltic Sea, and 29% in European traffic outside the Baltic Sea. The respondents' age averaged 35 (SD 11) years; 23% were women and 77% men. The amount of perceived stress varied between different occupational groups, the engine crew reporting the most stress. On the average, health status was reported as rather good. Personality characteristics were important explanators of perceived stress and health status. The most important were pessimism-optimism and ego strength. Of the work-related factors, the most important explanatory factors were disturbing noise, climatic conditions on board, occupational group, and received appreciation at work. The quality of interpersonal relations at work did not predict stress or health status. In this study 15-33% of the variance of perceived health status and stress could be explained.

Equilibria between vitamin B6-compounds and cyclodextrins.

Convenient chromatographic methods to measure equilibrium constants between cyclodextrins and aromatic compounds were developed. The use of 'Hummel-Dreyer' elution profile allows us to determine values above 15-20 M-1. The weaker associations (below 15-20 M-1) can be measured with cyclo-dextrin-derivatized Biogel P-2 column. The latter method is very suitable to determine the equilibrium constants between cyclodextrins and vitamin B6-compounds which can't be measured with the conventional photometric procedure.