Increased occupational physical activity does not improve physical fitness.

AIM: To determine the possible influence of high physical load in the workplace on the physical fitness of employees. METHODS: The subjects (494 men) were tested by means of Baecke's questionnaire for evaluation of the Work Index, measuring occupational physical load. The EUROFIT battery of tests was used for testing the functional and motor abilities of the subjects. RESULTS: Subjects with a higher Work Index (n = 274) performed worse than the subjects with a lower Work Index (n = 220), indicating that high physical load in the workplace does not necessarily mean improvement in functional and motor abilities. The "heavy" workers were only found to have a stronger handgrip. This could be attributed to the fact that physical activity performed at the workplace did not have adequate intensity, volume, and duration to effect positive changes in other motor and functional capacities.

Structure of polydispersed colloids characterised by light scattering and electron microscopy.

The dynamics of growth and aggregation of colloidal silver iodide particles was followed by the static light scattering method. The particles were treated as spheres and they were stable in size in the defined time interval. This approach enabled the use of the Zimm plots in order to determine the radii of gyration and the radii of spherical particles. Stable AgI colloids, either positively or negatively charged, showed the usual Zimm diagrams, while the diagrams were untypical when the stability of the colloids decreased. The untypical Zimm diagrams showed 'curves' with envelopes and 'curves' with minima in the unstable domain and in the domain where the most rapid nucleation occurs, respectively. Satisfactory agreement of particle sizes within the limits of accuracy, determined using static--and dynamic light scattering data and of the values obtained from the electron microscopic images was shown. Fitting the theoretical and experimental data, P(theta) functions showed that the particle shapes approach the theoretical model for spheres and thin discs. The colloid stability of polydispersed aggregates was also explained using the second virial coefficient, its negative sign implying interaction of particles in the solution, its positive value indicating formation of new particles from the supernatant solution. In addition, the colloid stability can be characterised by the mass fractal dimension. For positive stable colloids, Dm = 2.70 +/- 0.26, it can be related to the reaction controlled processes, whereas for negative stable colloids, Dm = 1.97 +/- 0.19, it was attributed to the diffusion controlled processes.

Respiratory function in active firefighters.

BACKGROUND: Exposure to environmental pollution during firefighting may results in the development of respiratory disorders in firefighters. METHODS: The health effects of firefighting on respiratory function was investigated in a group of 128 active firefighters by recording respiratory symptoms and measuring lung function. In addition, 88 control workers, not exposed to known pollutants were studied for the prevalence of acute and chronic respiratory symptoms. RESULTS: Significantly higher prevalences of dyspnea, nasal catarrh, sinusitis, and hoarseness were recorded in firefighters compared to control workers (P < 0.01). One subject developed asthma symptoms following two intense firefighting episodes. A high prevalence of acute symptoms experienced during and after fire extinguishing was also documented among these firefighters. Eye and throat irritation as well as headache were prominent. A logistic regression analysis of chronic respiratory symptoms demonstrated that odds ratios were significant for both duration of work exposure and for smoking. Lung function testing demonstrated a decrease in FEF75 in relation to predicted suggesting obstructive changes in the smaller airways. A regression analysis of ventilatory capacity tests indicated a positive relationship of forced vital capacity with length of employment, 1 s forced expiratory volume as well as FEF50 were related to smoking, and FEF75 was related to both smoking and length of employment. CONCLUSIONS: Our data suggest that firefighters are at risk for developing acute and chronic respiratory symptoms as well as obstructive airway changes.

Interaction of Proteus mirabilis urease apoenzyme and accessory proteins identified with yeast two-hybrid technology.

Proteus mirabilis, a gram-negative bacterium associated with complicated urinary tract infections, produces a metalloenzyme urease which hydrolyzes urea to ammonia and carbon dioxide. The apourease is comprised of three structural subunits, UreA, UreB, and UreC, assembled as a homotrimer of individual UreABC heterotrimers (UreABC)(3). To become catalytically active, apourease acquires divalent nickel ions through a poorly understood process involving four accessory proteins, UreD, UreE, UreF, and UreG. While homologues of UreD, UreF, and UreG have been copurified with apourease, it remains unclear specifically how these polypeptides associate with the apourease or each other. To identify interactions among P. mirabilis accessory proteins, in vitro immunoprecipitation and in vivo yeast two-hybrid assays were employed. A complex containing accessory protein UreD and structural protein UreC was isolated by immunoprecipitation and characterized with immunoblots. This association occurs independently of coaccessory proteins UreE, UreF, and UreG and structural protein UreA. In a yeast two-hybrid screen, UreD was found to directly interact in vivo with coaccessory protein UreF. Unique homomultimeric interactions of UreD and UreF were also detected in vivo. To substantiate the study of urease proteins with a yeast two-hybrid assay, previously described UreE dimers and homomultimeric UreA interactions among apourease trimers were confirmed in vivo. Similarly, a known structural interaction involving UreA and UreC was also verified. This report suggests that in vivo, P. mirabilis UreD may be important for recruitment of UreF to the apourease and that crucial homomultimeric associations occur among these accessory proteins.

Effects of developmental training of basketball cadets realised in the competitive period.

The analysis of effects of a two-month developmental training cycle realised within a basketball season revealed statistically significant positive changes at the multivariate level in components of motor-functional conditioning (fitness) status of the sample of talented basketball cadets (15-16 years). The greatest correlations with discriminant function were found in variables with statistically significant changes at the univariate level, more explicitly in variables of explosive and repetitive power of the upper body and trunk, anaerobic lactic endurance, as well as in jumping type explosive leg power. The presented developmental conditioning training programme, although implemented within the competitive period, induced multiple positive fitness effects between the two control time points in this sample of basketball players. The authors suggest that, to assess power of shoulders and upper back, the test overgrip pull-up should not be applied to basketball players of this age due to its poor sensitivity. Instead, they propose the undergrip pull-up test, which is a facilitated version of the same test. The results presented in this article reinforce experienced opinion of experts that, in the training process with youth teams, the developmental conditioning training programme is effectively applicable throughout the entire competitive season. The proposed training model is a system of various training procedures, operating synergistically, aimed at enhancing integral fitness (preparedness) of basketball players. Further investigations should be focused on assessing effects of both the proposed and other developmental training cycle programmes, by means of assessing and monitoring actual quality (overall performance) of players, on the one hand, and, on the other, by following-up hormonal and biochemical changes over multiple time points.

[Medicine in sports or sport medicine?] ]. / Medicina u sportu ili sportska medicina?

Sports medicine is a profession pertaining to primary health care of sport population (competitors, coaches, referees, participants in sports recreation). It embraces the physical and mental health protection and promotion of participants in relation to a particular sport activity and sport environment, directing athletes to a sport and adapting them to sport and the sport to them. Sports medicine takes part in selection procedure, training process planning and programming, and cares for epidemiological, hygienic, nutritional and other problems in sport. The Republic of Croatia belongs to those world states in which the field of sports medicine is regulated neither by a law or by profession. A consequence is that wide circle of physicians and paramedics work in clubs and various medical units without any legal or/and professional control not being adequately educated nor having licence for it. This review is an appeal to the Croatian Medical Chamber and the Ministry of Health to make efforts to promote the education and medical profession in sports medicine.

Physical activity of urban adult population: questionnaire study.

AIM: To assess the level of physical activity of an urban population according to gender, age, smoking, and educational differences. METHODS: The sample comprised 594 men and women living and working in Zagreb, Croatia. Work, sport, and leisure-time activity indices were obtained by the Baecke's questionnaire. Significance of differences was tested by the Student's t-test. The relation between the indices and the education was determined by correlation analysis. RESULTS: Women had lower work and sport indices score, and higher leisure-time activity index. After the age of 50, women participated significantly more in sport activities than men. There was a negative correlation between the education and the work index, and a significantly positive correlation between the educational level and the sport activity index, regardless of gender and age. Women smokers participated to a significantly lesser extent in sport activities than women non-smokers. Such differences were not observed in men. CONCLUSION: People with lower educational level sustain more workload at their jobs than those with higher education. More educated people participate more in sport activities, although leisure time activity is not significantly related to education. In women, participation in sport activities negatively correlates with the smoking habit.

Respiratory function in female workers occupationally exposed to organic dusts in food processing industries.

Respiratory consequences of work in food processing industry were studied in 764 female workers exposed to organic dusts associated with the processing of green and roasted coffee, tea, spices, dried fruits, cocoa and flour. A group of 387 female workers not exposed to respiratory irritants served as controls for the prevalence of acute (during work shift) and chronic respiratory symptoms. A greater prevalence of all acute and chronic respiratory symptoms was consistently found among exposed workers than among control workers. The highest prevalence of chronic respiratory symptoms was recorded for chronic cough (40%), followed by acute symptoms of dry cough (58.7%). The difference in the prevalence of chronic respiratory symptoms between the exposed and control workers was in general significant (p < 0.01 or p < 0.05). Mean acute reductions of lung function over the work shift were recorded in all of the studied groups; the mean across-shift decrease as a percentage of preshift values was particularly marked in FEF25 (-26.7%), FEF50 (-21.6%), followed by FEV1 (-9.9%) and FVC (-3.7%). The preshift (baseline) values of ventilatory capacity were decreased in comparison to the predicted ones, and were lowest for FEF50 and FEF25. This finding indicated an effect of organic dust on small airways. Our analysis suggested that both dust exposure and smoking history contributed independently to these respiratory findings. Disodium cromoglycate (DSCG) significantly diminished across-shift reductions for FEF50 and FEF25 in a subgroup of the examined workers. Our data suggested the female workers employed in food processing industry to be at risk of developing both acute and chronic respiratory symptoms as well as ventilatory capacity impairment as the result of occupational exposures.

[Active rest during work periods]. / Aktivni odmori u procesu rada.

Every work, especially professional work, induces fatigue which diminishes work efficacy. Active rests with aim-oriented recreational activities implemented in the work process are very efficacious in removing fatigue symptoms. The paper discusses examples and mechanisms of making work and recovery faster and more successful by programming physical activity at the beginning of work and during regular and added rests in accordance with the established critical time during the eight-hour work shift.

Vimentin expression is differentially regulated by IL-2 and IL-4 in murine T cells.

IL-2 and IL-4 are T cell growth factors that are produced by different T cell subsets and have distinct roles in lymphocyte biology. Despite their importance in the immune system, little is known about the genes that these lymphokines may specifically control and the interaction of these lymphokines in regulating the expression of their target genes. In this paper, we use the factor-dependent murine T cell line (CT.4R) to investigate the interaction of IL-2 and IL-4 in regulating gene expression. We report that the intermediate filament protein vimentin is differentially regulated by these lymphokines. Cells grown in IL-2 typically express 10- to 20-fold more vimentin and vimentin RNA than those grown in IL-4, but express similar levels of other cytoskeletal proteins including actin and tubulin. Vimentin was specifically induced by IL-2 and apparently suppressed by IL-4 in normal lymph node T cells, suggesting that its differential regulation by these lymphokines is physiologically relevant. We investigated the synergy between IL-2 and IL-4 in regulating the expression of vimentin RNA and compared it to that of two other lymphokine-responsive genes, pancreatic lipase and the IL-2R alpha subunit. Complex regulatory interactions were revealed: IL-4 suppressed the ability of IL-2 to induce vimentin RNA but not IL-2R alpha RNA, whereas IL-2 inhibited the ability of IL-4 to induce lipase RNA. These results indicate that IL-2 and IL-4 can cross-regulate lymphokine-responsive genes and can simultaneously exert both positive and negative regulation of different genes within the same cell.

Characteristics of the morphological and functional status of kayakers and canoeists.

A study of anthropometric and functional characteristics was conducted in a sample of 29 athletes, flatwater racers 18 kayakers and 11 canoeists. The results of morphological tests suggest an evident reduction of subcutaneous fat, above-average values of limb circumferences (especially upper limbs) and of body mass, attributable to a high proportion of lean body mass. Trunk extension strength was to be below the average, while the strength of the remaining analyzed static movements were on the level of trained persons. Aerobic capacity, i.e. the functioning of the cardiopulmonary system, in the sample under discussion has shown above-average values, comparable to those obtained in athletes in the aerobic sports group. The results of discriminant analysis applied separately to morphological, dynamogenic and aerobic characteristics with the aim to identify possible differences between the two sports suggest that our sample constituted a homogeneous group, regardless of which of the two sports were practiced.

[Scientific basis and professional concept of instituting a medical program of active recreation]. / Znanstvene osnove i doktrinarni stavovi o provodenju medicinski programiranih aktivnih odmora.

Physical activity is essential to health and should be exercised in accordance with one's functional and health state. Among the most advanced forms of programmed physical activity is medically programmed active leisure (MPAL). The implementation of MPAL in practice relies on research and on scientifically based concepts and attitudes which control the selection of persons for and their inclusion in MPAL. In Croatia MPAL is a form of specific care for worker's health, which is conducted in compliance with the health care and health insurance acts.