[Wood dust exposure in handicraft companies in Lazio: preliminary findings]. / Esposizione a polveri di legno in aziende artigiane del Lazio: risultati preliminari.

The aim of this study is to evaluate the wood dust exposures characterizing the working more to risk. Two selectors for inhalable fraction were been used: IOM sampler (Institute Occupational Medicine) and conical sampler. The sampling time is choosen by environmental airborne dust and it has varied around three and four hours. The surveys involved some companies of the Lazio that carried out the second working of wood that predict the transformation in ultimate products. The woodworking processes investigated have been grouped in three different classes: wood dissection; planning and moulding; sanding. The results have shown that the medium concentration of wood dusts, obtained in three processes investigated ranges from 2 mg/m3 to 4 mg/m3. The higher amounts is of 16 mg/m3 and it have been obtained during the sanding. Moreover the dust collected by IOM sampler was always higher than by conical sampler probably it is due to large particulates that were projected into IOM causing an overestimate of the amount of wood dust particulate that was inhalable. This study need to of more personal sampling for being able to carry out an exhaustive statistical analysis.

[The risk of inhalable wood dust: assessment of workers exposure wood working factories]. / Il rischio da polveri di legno inalabili: valutazione dell'esposizione professionale nelle falegnamerie.

The International Agency for Research on Cancer RC) has classified wood dust as carcinogenic to humans based on demiological and experimental evidence. Exposure to wood dust may use respiratory and dermal symptoms and diseases. The aim of this work was to estimate occupational exposure to inhalable wood dust adopting the formal procedure described by UNI EN 689/97. The exposure of 23 workers in three different working day was measured. In total, 69 personal air samplings were carried out at five wood working factories. Inhalable fraction of airborne dust was collected on 5 microm pore size, 25 mm diameter PVC filters utilizing the IOM samplers. The quantity of the wood dust was determined with gravimetric method. The results show that about 13% of the exposure values exceed the limit of 5 mg/m3 specified by the Italian Law Decree 66/2000 and about 48% of personal exposures are lower then the limit value. Prevention measures, technological solutions and personal protection equipment should be adopted in order to reduce worker's exposure.

[Organic artificial fibers: properties and toxicity]. / Fibre artificiali organiche: proprietà e tossicità.

Now among asbestos substitutes, the man-made organic fibers (MMOFs) find interesting applications on the industrial side. This class includes aramidic, polyacrylic, polyamides, polyolefins and polyvinylic fibers and it has been listed in category 3 of IARC classification (not classifiable as to carcinogenicity to humans). The aim of this study is to provide a panoramic regarding the toxicity of MMOFs present on the market according to their chemical-physical properties. Three materials have been taken in to consideration: the polyacrylonitrile (PAN), the polyvinyl alcohol (PVA) and the Kevlar. Each of them has been observed by the Scanning Electron Microscopy and Energy Dispersive Spectroscopy to estimate the morphology and the mean diameter. The obtained mean diameter of fibers is 10.50 microm for the PAN, 16.60 microm for the PVA and 11.61 microm for the Kevlar. The last one presents fibrils having a diameters in the range 0.2-1.6 microm. The ability of the Kevlar to produce fibrils with dimensions less than 1 microm, after abrasion or mechanical stress of other kind, is the cause of numerous studies based on the evaluation of their biosolubility. Finally we show some spectra obtained from the analysis of these fibers through Fourier Transform Infrared Spectroscopy (FTIR).

[Active surveillance of nosocomial infections in heart surgery patients: implementation of the American National Nosocomial Infections Surveillance (NNIS) System in a large hospital in Rome]. / Sorveglianza attiva delle infezioni ospedaliere nei pazienti cardiochirurgici: applicazione del metodo del National Nosocomial Infections Surveillance (NNIS) System americano in un grande ospedale di Roma.

The authors present the implementation of the American NNIS System method for active surveillance in the heart surgery and its intensive care unit (ICU) of a large hospital in Rome (almost 1.000 beds). This surveillance was based on full time infection control professionals. Device-associated infection rates were calculated for adult ICU surveillance component. For surgical patient surveillance component we used the surgical site infection (SSI) risk index based on wound class, duration of operation and American Society of Anesthesiology score. The NNIS System method allowed us to understand the most relevant problems in heart surgery patients: in comparison with NNIS data, we found high rates of SSIs both in procedures on valves and in coronary artery bypass grafts. The central line-associated bloodstream infection rate was higher than the American median rate. Therefore, we decided to focus on surgical risk factors linked to SSIs and to revise recommendations for intravascular-device use. In conclusion, in our experience the NNIS System method proved to be a very useful and versatile tool for nosocomial infections active surveillance.

[Exposure to artificial mineral fibers in public buildings]. / Esposizione a fibre minerali artificiali in edifici pubblici.

Man-made mineral fibers are widely used as asbestos substitutes in many application fields. Therefore toxicology studies and indoor pollution surveys, related to man-made mineral fibers, are becoming very important. Several surveys were made in office buildings where the main source of indoor pollution was the dispersion of man-made mineral fibers contained in the insulation materials (under-ceiling panels, partitions and material used in air-conditioning installations). Samples of the insulation materials were taken and analyzed by phase contrast optical microscopy and scanning electron microscopy equipped with energy-dispersive X-ray analysis. For some samples the fiber diameter measurements were made and the related statistical parameters were calculated. The measured airborne fiber concentrations showed non relevant man-made mineral fiber dispersion in the environment. The relative exposure limits and regulations in force are discussed.

Groshong catheters: technical aspects and clinical features.

After thousands of Groshong catheter applications over more than twenty years, the cause of blood withdrawal drawbacks is not yet completely understood. This phenomenon - which is not typical of closed-tip catheters since it is also common in open-tip catheters - in the Groshong catheter is attributed to the valve (ball-valve effect). The aim of this work is to understand the relationship between causes and effects in order to provide clinicians with practical solutions. Out of the 16 catheters examined, we observed no clear correlation among electron microscope ultrastructural analysis, valve closing pressure, intraluminal clots and clinical failures after different implantation times up to a maximum of 36 months. The ultrastructural analysis revealed an optimal no-time-related aspect for internal and external surfaces, while the closing pressure in each case was compatible with the efficiency of the working valve (range 22-36 cmH 2 O). We conclude that the blood withdrawal drawbacks cannot be attributed to a single cause and certainly not to the silicone biostability or directly to the valve. Different studies are suggesting that clinical failures can be the re-sult of several different causes such as slime or clots in the internal catheter surfaces and fibrin sleeve in the external catheter surfaces. These are common causes in open-tip catheters and we believe that the presence of valves on the tip of the Groshong may encourage inferences. Our suggestion is to place the tip of the Groshong catheter in atrium one centimetre after the junction with the vena cava. After the implant, it is possible to remove the causes of drawbacks by strong flushing using a 5-ml syringe and/or postural manoeuvres.

[Inter-laboratory comparison of measuring concentration of asbestos fibers less than 5 microM in length using phase-contrast microscopy]. / Confronto inter-laboratorio per la determinazione delle fibre di amianto inferiori a 5 microM di lunghezza con il metodo della microscopia ottica in contrasto di fase.

Airborne asbestos fibers at the workplace are usually measured by phase-contrast microscopy (PCM), using the membrane filter method (MFM). Although the MFM has an international standardization, the application of this method can lead to wide differences in results. An inter-laboratory study, involving 19 laboratories, was organized. Two fiber classes were counted: 1) fibers greater than 5 microns in length and less than 3 microns in diameter; 2) fibers less than 5 microns in length and less than 3 microns in diameter. The results of each laboratory were normalised to the mean and their counting performance was compared. The estimated coefficients of variation or relative standard deviation (CV) of the normalised results were fitted assuming a constant component (K) and a component depending on the fiber count (Poisson component: mu-1/2). Fitting showed that the constant K is about 0.36 for counting fibers greater than 5 microns in length and about 0.52 for counting fibers less than 5 microns long. It was shown that counting the latter fiber class is influenced primarily by subjective laboratory-to-laboratory differences.

Wollastonite fibers in vitro generate reactive oxygen species able to lyse erythrocytes and activate the complement alternate pathway.

Wollastonite fibers were tested in vitro for their ability to produce reactive oxygen species (ROS) with two different systems: a cell-free reactive mixture containing deoxyribose and a polymorphonuclear leukocyte suspension. After adding the fibers, we measured the thiobarbituric acid-reactive substances produced by deoxyribose degradation and luminol-enhanced chemiluminescence, respectively. Compared with asbestos, wollastonite fibers produced higher ROS levels both in the PMN suspensions and in the cell-free reactive mixtures. A large amount of these ROS were not hydroxyl radicals. Indeed we obtained remarkable differences in ROS generation between unground and ground wollastonite fibers and negative results with fibers modified with ferric chloride and dithionite. In addition, ROS generation was partially inhibited (by 46-54%) in the reactions performed in the presence of 1,3-dimethyl-2-thiourea (DMTU), a strong hydroxyl radical scavenger. Wollastonite fibers were also analyzed for their ability to lyse erythrocytes and activate complement. Hemolytic potency was about twice that of chrysotile and half that of crocidolite. The levels of complement activation (via the alternate pathway) were about four-fifths of those measured in zymosan-activated plasma (a typical stimulus used to activate the alternate pathway), equal to those obtained with crocidolite, and two-thirds of those found with chrysotile. The addition of DMTU markedly reduced both these activities. Since asbestos fiber toxicity is mainly due to hydroxyl radical generation, our results indicate that wollastonite fibers are probably less toxic than asbestos fibers.

Cardiopulmonary exercise response in patients with left ventricular dysfunction or heart failure: a noninvasive study by gas exchange and impedance cardiography monitoring.

We investigated the upright bicycle exercise cardiopulmonary response in 20 patients with left ventricular dysfunction (LVD, secondary to previous myocardial infarction, left ventricular ejection fraction range 18-44%). Ten patients (48 +/- 7 years) asymptomatic (I NYHA class) without drug treatment (LVD group). The others (n = 10) (50 +/- 1 years) complained of dyspnea and/or fatigue despite therapy (NYHA II-III). They represented the heart failure (HF) group. Eight sedentary men (40 +/- 10 years) served as controls. Controls and patients performed stress testings under drug treatment, when administered. Anaerobic ventilatory threshold (ATge) was considered as an index of submaximal exercise while peak exercise VO2 (Peak VO2) was considered the maximal volitional exercise capacity. The ratio between minute ventilation (VE) to carbon dioxide release (VCO2) (VE/VCO2) was assessed to evaluate the ventilatory response during exercise. We coupled gas exchange assessment (2001, MGC) with noninvasive monitoring of stroke volume (SV) by impedance cardiography (NCCOM3, BOMED) and total systemic vascular resistances (TSVR; by auscultatory blood pressure measurement). In controls VO2 increase during exercise was related to higher heart rate (HR) and SV both from resting to ATge and from this point to the peak. TSVR declined during both steps. In patients with HF VO2 rose from resting to ATge (by faster HR and unchanged SV). VO2 increased slightly from this point to Peak VO2. This result was related to flat HR increase and unchanged SV as well as TSVR. In patients with LVD VO2 increased similarly to controls from resting to ATge and less above the threshold. In these patients both HR and SV increased during submaximal exercise. From ATge to Peak VO2 only HR increased. TSVR declined significantly similarly to controls. The VE/VCO2 ratio was higher at peak exercise in patients with HF compared to controls. Different determinants were demonstrated in patients with left ventricular dysfunction with mild or symptomatic chronic heart failure (CHF). These findings and the increased ventilatory response in patients with CHF can explain different changes of VO2 in these patients during submaximal and maximal voluntary exercise and contribute to explain exercise-induced exertion in these subjects.

Different protocols generate variations in systolic blood pressure response after exercise in patients with coronary artery disease.

Some patients with coronary artery disease (CAD) and exercise-induced myocardial ischemia demonstrate no change or a paradoxical increase in systolic blood pressure (SBP) during recovery following exercise. Previous studies have investigated the significance and clinical usefulness of analysis of recovery SBP response in detecting CAD, but conflicting data have been reported. Different protocols were used for the time of SBP recording and either bicycle or treadmill testing. We studied the exercise response in 64 male patients investigated for CAD who underwent symptom-limited treadmill stress testing during electrocardiographic monitoring and serial recording of blood pressure. Forty-three patients showed on or more stenoses of at least 70% at angiography (CAD). Twenty-one patients with normal coronary tree or slight lesions served as controls. The sensitivity (true positive/all CAD patients), specificity (true negative/all CAD-free patients), and the correct classification rate (correct diagnoses/all subjects) were assessed by standard ST segment analysis and two recovery SBP ratios calculated by dividing the first minute recovery SBP by the immediate postexercise value (RR/R) or by the true peak exercise value (RR/P). ST segment analysis achieved 53% sensitivity, 57% specificity, and 54% correct classification, the RR/R ratio achieved 73%,23%, and 60%, and the RR/P ratio 53%, 71%, and 59%, respectively. There were significant differences in results using these ratios. Time of SBP recording generated discrepancies in recovery SBP ratios. Therefore, differences in the timing of SBP measurement may generate conflicting clinical indications.

Incidence and complexity of ventricular ectopy during Holter monitoring in patients with exercise-induced myocardial ischemia and normal or mildly reduced left ventricular function.

We aimed to assess the relationship between frequent and complex ventricular ectopy by continuous electrocardigraphic 24-hours Holter monitoring in patients with coronary artery disease and inducible ischemia during exercise procedures. We investigated 609 consecutive patients. They were referred for chest pain (28% with a previous myocardial infarction, older than 6 months). In all population patients radionuclide ventriculography showed a global normal or mildly reduced left ventricular function (ejection fraction > 45%). All patients showed exercise-induced myocardial ischemia (ST depression) and exercise thallium-201 reversible defects. During Holter monitoring, in study population, divided according to incidence of premature ventricular complexes (PVC), we found a higher prevalence of complex ventricular arrhythmias (CVA) (bigeminy, couplets, ventricular tachycardia, multiformity) in patients with high incidence of PVC. The relationship between frequent and complex ventricular ectopy has been observed also during ischemic ST shifts occuring during 24-hours monitoring. In contrast, the R on T phenomenon was not related to incidence of PVC. Therefore, in patients with exercise-induced myocardial ischemia and global normal or mildly reduced left ventricular function there is a relationship between frequent and complex ventricular ectopy, as previously suggested in CAD patients with depressed left ventricular function.