Muscle activation during leg-press exercise with or without eccentric overload.

PURPOSE: This study sought to investigate the electromyographic activity of the vastus lateralis (VL) muscle during concentric-eccentric exercise using a new concept leg press machine enabling a preset overloading in the eccentric phase. METHODS: Ten young males familiar with resistive exercise were recruited for this study. Tests were performed on a Leg-press Biostrength® (Technogym S.p.A., Italy). The load was set to 70% and 80% of one-repetition maximum (1-RM). The participants performed 2 sets of 6 repetitions at each relative load with (ECC +) and without (ISOW) an eccentric overload equivalent to 150% of the concentric load. A metronome was employed to maintain the selected cadence. Sets were separated by a 5-min rest. Surface electromyography (EMG) of VL was recorded and integrated (iEMG). RESULTS: Results showed a higher iEMG in ECC + with respect to ISOW at both intensities (+ 29% for 70% 1-RM, p < 0.01 and + 31% for 80% 1-RM, p < 0.001). No statistically significant differences were detected between concentric and eccentric phase in both ECC + conditions. CONCLUSIONS: Training with a 150% eccentric overload provides a ~ 30% greater motor unit recruitment of the VL muscle in leg press exercise. Moreover, the results show that the eccentric overloading provided by the Biostrength® machine enables training at the same level of neural activation of the concentric phase. Hence, the derecruitment of motor units, normally observed during the eccentric phase when using conventional training machines, was overcome using the Biostrength® machine; this observation seems particularly important for maximizing neuromuscular responses to strength training.

Statutory prevention of work injuries in Italy: an effectiveness evaluation with interrupted time series analysis in a sample of 5000 manufacturing plants from the Veneto region.

OBJECTIVES: According to Italian law, prevention of injuries in the workplace falls under the National Health System Service of Prevention, Health and Safety at Work (SPISAL). In a sample of about 5000 industrial firms in the Veneto region (North-Eastern Italy), the study examines the impact of SPISAL safety programmes on injuries. METHODS: The study is based on the before-and-after comparison of injury rates in 795 industrial settings that were subject to SPISAL interventions and 4186 reference firms, which were all manufacturing industries with >10 employees; construction companies were excluded. The time window (2001-2007) was chosen in order to have 8 quarters of observation before and 8 after the intervention. The National Institute for Workers' Compensation provided data on injuries and plants, while SPISAL gave information on interventions carried out. The preintervention and postintervention rates of injuries were compared by means of interrupted time series analyses, estimating the rate ratio (RR) with a 95% CI. RESULTS: Inspection after injury reduced by 24% (RR=0.76; 95% CI 0.65 to 0.90; p=0.001) all injuries, and by 36% (RR=0.64; 95% CI 0.50 to 0.83; p=0.001) severe injuries (fatalities, lost workdays >30, degree of permanent disability >0). These changes occurred immediately and persisted for 2 years. The effects of programmed inspections were never significant. CONCLUSIONS: It can be presumed that, after a severe injury, the employees raised their standard of what they considered good work safety and, at the same time, the employers were pushed to improve the work environment as a result of the sudden attention from the workplace hygiene and safety authority and court authority. Inspection after injury was an effective strategy; however, confirmatory evidence is needed.

Clinical leadership and hospital performance: assessing the evidence base.

BACKGROUND: A widespread assumption across health systems suggests that greater clinicians' involvement in governance and management roles would have wider benefits for the efficiency and effectiveness of healthcare organisations. However, despite growing interest around the topic, it is still poorly understood how managers with a clinical background might specifically affect healthcare performance outcomes. The purpose of this review is, therefore, to map out and critically appraise quantitatively-oriented studies investigating this phenomenon within the acute hospital sector. METHODS: The review has focused on scientific papers published in English in international journals and conference proceedings. The articles have been extracted through a Boolean search strategy from ISI Web of Science citation and search source. No time constraints were imposed. A manual search by keywords and citation tracking was also conducted concentrating on highly ranked public sector governance and management journals. Nineteen papers were identified as a match for the research criteria and, subsequently, were classified on the basis of six items. Finally, a thematic mapping has been carried out leading to identify three main research sub-streams on the basis of the types of performance outcomes investigated. RESULTS AND CONTRIBUTION: The analysis of the extant literature has revealed that research focusing on clinicians' involvement in leadership positions has explored its implications for the management of financial resources, the quality of care offered and the social performance of service providers. In general terms, the findings show a positive impact of clinical leadership on different types of outcome measures, with only a handful of studies highlighting a negative impact on financial and social performance. Therefore, this review lends support to the prevalent move across health systems towards increasing the presence of clinicians in leadership positions in healthcare organisations. Furthermore, we present an explanatory model summarising the reasons offered in the reviewed studies to justify the findings and provide suggestions for future research.

[A new scale for measuring the psycho-physical effects of work-related stress in a perspective of methods integration]. / Una nuova scala di misura degli effetti psico-fisici dello stress lavoro-correlato in una prospettiva d'integrazione di metodi.

BACKGROUND: This study fits into a perspective of integrated work-related stress assessment, in response to the need to limit the common method variance and the role played by individual variables in subjective measures. OBJECTIVES: The goal of this study was to check the metric properties of a new scale of mental and physical strain developed for the evaluation of stress symptoms by the physician and to detect the antecedents of psycho-physical symptoms, in terms of both individual and work characteristics, through an integrated approach. METHOD: The study was conducted on 409 workers involved in health surveillance activities, to whom the new scale and a subjective assessment tool were administered. RESULTS: Confirmatory factor analysis showed that the scale is a reliable tool for hetero-evaluation of psycho-physical symptoms attributable to stress at work. Moreover, specific individual characteristics, such as the presence of prior health disorders and the female gender, and organizational features, such as the pathological work/life conflict and the workload, were found to be risk factors in relation to psychological and physical strain. Age, consumption of alcoholic beverages between meals, relationships with colleagues, and the characteristics of the workplace were instead found to be important protective factors. DISCUSSION: The adoption of an integrated approach made it possible to improve and study in depth the ways of work-related stress assessment, highlighting the pivotal role of the occupational health physician making the evaluation.

Aging and smoking increase the frequency of sister-chromatid exchanges (SCE) in man.

The frequency of SCE was determined in lymphocytes of 88 healthy human subjects, not occupationally exposed to known genotoxic agents, who were uniformly distributed in several classes of age (from 16 to 70 years), including an equal number of smokers and non-smokers, and of males and females. Our results indicate that the frequency of SCE increases linearly with age and that smoking enhances the frequency of SCE independently of age and sex.

The micronucleus assay in human exfoliated cells of the nose and mouth: application to occupational exposures to chromic acid and ethylene oxide.

We have applied the micronucleus (MN) assay to exfoliated cells of buccal and nasal cavities to monitor the genotoxic risk in a group of workers exposed to chromic acid and in another group exposed to ethylene oxide (EtO). The first group comprised 16 subjects working in a 'hard' type chrome-plating factory showing increased chromium absorption and chromium-induced rhinopathy. The second group comprised 9 subjects working in a sterilization unit, exposed to EtO concentrations lower than 0.38 ppm as timed weighted average (TWA) for a working shift; 3 of them were involved in a acute exposure too. The frequency of MN in buccal mucosa was within the norm for exposure both to chromium and to EtO. The MN frequency in nasal mucosa was not altered in chromium platers, whereas a significant increase (p less than 0.01) in MN was found in 2 out of 3 subjects involved in the accidental EtO leakage and a non-significant increase in MN was found in the group chronically exposed to EtO.

Variations of SCE frequencies in peripheral lymphocytes of ex-smokers.

We measured SCE frequencies over a period of 8 months in 14 smokers who stopped smoking at the start of the study. In a first group of 10 subjects, who did not resume smoking during the period of cytogenetic follow-up, a lowering of SCE frequencies was already evident after 18 days and this became statistically significant after 78 days. SCE decrease was related to the logarithm of the period (in days) for which smoking was interrupted (r = 0.98; p less than 0.001). In a second group of 4 subjects, who at various times resumed smoking, the decrease of SCE followed the same pattern as in the first group during the period of nonsmoking, but SCE frequencies rose even higher once smoking was resumed. Our study indicates that the decrease of SCE in ex-smokers is rather rapid during the first 78 days after stopping smoking, and much slower from the 78th to the 233rd day.

No evidence of chromosomal instability in nevoid basal-cell carcinoma syndrome.

The nevoid basal-cell carcinoma syndrome (NBCCS) is a rare multisystem disorder characterized by several alterations of the skin, skeletal, nervous, endocrine system. These patients are more susceptible to cancer and suggestions have been made about an association with the chromosomal breakage syndromes. We studied the induction of chromosomal aberrations by mitomycin C (MMC) and bleomycin and that of sister-chromatid exchanges by MMC and 4-nitroquinoline N-oxide in lymphocytes of 4 NBCCS patients. The frequencies of both spontaneous and induced cytogenetic effects were within normal ranges, suggesting that there is no chromosomal instability in NBCCS patients.

Micronucleated cells in nasal mucosa of formaldehyde-exposed workers.

The frequency of micronuclei (MN) and cytology of respiratory nasal mucosa cells were evaluated in 15 non-smokers exposed to formaldehyde in a plywood factory. Each subject was paired with a control matched for age and sex. Mean levels of exposure to formaldehyde ranged from about 0.1 mg/m3 in the sawmill and shearing-press departments to 0.39 mg/m3 in the warehouse area. There was a contemporary exposure to low levels of wood dust (inspirable mass ranged from 0.23 mg/m3 in the warehouse to 0.73 mg/m3 during sawing operations). Nasal respiratory cell samples were collected by an otorhinolaryngologist near the inner turbinate using a brush for endocervical cytology. After staining (Feulgen plus Fast Green and Papanicolaou's method for MN analysis and cytology, respectively), about 6000 cells were screened for micronuclei and scored in parallel for cytology according to a histopathological scale. A higher frequency of micronucleated cells was observed in the exposed group than in the controls (0.90 +/- 0.47 vs. 0.25 +/- 0.22, Mann-Whitney U test: p less than 0.01). Cytological examination indicated chronic phlogosis in the nasal respiratory mucosa of plywood factory workers, with a high frequency of squamous metaplasia cells (mean score 2.3 +/- 0.5 vs. 1.6 +/- 0.5 in the control group, Mann-Whitney U test: p less than 0.01).

Evaluation of chromosomal aberrations in lymphocytes and micronuclei in lymphocytes, oral mucosa and hair root cells of patients under antiblastic therapy.

In 7 patients undergoing antiblastic chemotherapy for the first time, the structural chromosomal aberration (CA) test in peripheral lymphocytes was compared with the micronucleus (Mn) test in lymphocytes, in oral cavity cells and in hair root cells of the scalp. The last test is being proposed for the first time. The CA and Mn frequencies induced by chemotherapy were compared with the baseline (pretreatment) frequencies of the patients and with confidence limits calculated in 4 control groups studied for CA, Mn in lymphocytes, Mn in oral cavity cells and Mn in hair root cells, respectively. The studied chemotherapies induced a clear cytogenetic effect in at least 2 of the tests studied with the exception of interferon-alpha 2b (patient 6) and interferon + low doses of cis-platinum (patient 2) which did not appear to cause evident chromosomal damage. The response to chemotherapy is generally characterized by an increase in Ca and Mn, reaching a peak value and then decreasing in the following weeks. The CA test proves to be the most sensitive despite the fact that CA were analyzed in an average of 100 cells per sample against the 500-3000 cells analyzed for Mn. The efficiency of Mn to detect CA is in the following order: Mn in lymphocytes greater than Mn in buccal cells greater than Mn in hair root cells. The last test appears to be very promising but, used following the current method, does not appear suitable to monitor acute exposure.

Cytogenetic damage in workers exposed to ethylene oxide.

Sister-chromatid exchanges (SECs) and chromosomal aberrations (CAs) were detected in the peripheral lymphocytes of 41 sanitary workers exposed to ethylene oxide (EO) in the sterilizing units of 8 hospitals in the Venice Region. The first group (19 workers) was exposed to 10.7 +/- 4.9 ppm EO, expressed as the time-weighted average concentration for an 8-h working day (TWA/8 h conc.), and the second group (22 workers) to 0.35 +/- 0.12 ppm. Each exposed worker was paired with a control of similar age and smoking habits. A highly significant (P less than 0.001) increase in the mean frequency of SCEs was found in the higher exposure group, 14 (74%) exposed subjects having significantly increased levels of SCEs compared to their matched controls. In the lower exposure group, the increase in mean frequency of SCEs was lower, though still significant (P less than 0.05): 7 (33%) exposed subjects had higher and 1 (5%) had a lower SCE level than the matched controls. From the first group, 10 subjects, 7 of whom had increased SCE levels, were reanalysed 12-18 months after their exposure had been lowered or interrupted: in only 2 of them the SCE level was significantly decreased. A statistically significant correlation between SCE frequency and level of EO exposure (TWA/8 h conc.), as well as a multiple correlation between SCE level and EO exposure, smoking and age were found. However, no interaction could be detected between EO exposure and smoking in the induction of SCEs. In controls, SCE frequency was correlated with smoking and age. In the higher exposure group, the number of both chromatid- and chromosome-type aberrations, independent of gaps, was significantly increased, whereas in the lower exposure group only the frequency of chromosome-type aberrations, excluding gaps, was statistically higher than in controls. The level of CAs remained to a great extent unchanged in the 10 subjects re-examined at a later stage after lowering or halting exposure. Taking the group as a whole, the frequency of cells with total CAs was found to be weakly (P = 0.05) correlated with EO exposure, and was not correlated with smoking, age or SCE frequency.

Studies of biological and chemical monitoring of low-level exposure to ethylene oxide.

Ten sanitary workers exposed to concentrations of ethylene oxide below 1 ppm were studied to determine whether effects could be observed at low exposure levels. A significant increase in the number of sister chromatid exchanges in cultured lymphocytes was found only for five subjects with relatively high exposure in the sterilization area. However, it was not possible to separate clearly the effect of smoking from that of ethylene oxide exposure. No increase in the frequencies of micronuclei in lymphocytes and buccal cells was found. The level of 2-hydroxyethyl adducts to the N-terminal valines in hemoglobin responded in a reliable fashion to chronic ethylene oxide exposure and smoking. Furthermore, measurement of levels of 2-hydroxyethyl adducts to the N-terminal valines in hemoglobin made it possible to reconstruct the dynamics of a leakage of ethylene oxide which involved three workers.

[Return of immigrants: a cluster analysis of mesotheliomas among residents of the Veneto region who used to work at the ETERNIT AG factory at Niederurnen, Switzerland]. / Emigrazione di ritorno: un cluster di mesoteliomi in Veneto tra ex-lavoratori della Eternit AG di Niederurnen, Svizzera.

We identified 5 mesotheliomas among Italian migrant workers who returned home and settled in the Veneto Region, after employment at the ETERNIT AG factory in Switzerland. During the 1970s the factory employed about 1000 workers and the presence of Italian migrants was relevant. The cluster confirms that migration for work has caused exposures to carcinogenic substances and confirms that neoplastic diseases are occurring among those resettled in Italy and helps explaining the high occurrence of mesotheliomas in this country.

[Pleural mesothelioma in women in the Veneto Region who used to work as rag sorters for textile recycling and paper production]. / Mesoteliomi pleurici insorti in donne, residenti in Veneto, addette alla cernita di stracci presso "robe vecchie" e cartiere.

The paper reports 9 cases of mesothelioma diagnosed by means of histology or cytology that were observed among women resident in the Veneto Region, Northern Italy, whose only activity that could involve exposure to asbestos was as rag sorter. These cases are part of a group of about 260 subjects with mesothelioma whose entire working and residential history has been collected. The women worked as rag sorters between the 1940's and 1960's in textile recycling (8 cases) or (one case) at a paper mill where cotton was used for paper production. The work as rag sorter helps to explain the high proportion of mesotheliomas among women with an occupational exposure to asbestos.