[Sleep disorders in cement workers]

Obstructive Sleep Apnea Syndrome (OSAS) and Excessive Daytime Sleepiness (EDS) are sleep disorders which can increase cardiovascular risk. An health survey was performed on the cement workers to estimate the prevalence of sleep disorders and to investigate occupational, personal and health risk factors that could influence it. A total of 761 male workers, employed at 10 different cement plants of South Italy and Sicily, were examined. All subjects gave informed consent to take part in the survey. The following questionnaires were administered: Berlin Questionnaire to estimate the high risk of OSAS, Epworth Sleepiness Scale for EDS, a questionnaire posing questions about working conditions, personal characteristic, lifestyle, past history of disease and present illness. Statistical analysis was performed with the statistical package SPSS. The prevalence of high risk of OSAS and of EDS resulted respectively in 24.2% and 3.4% of workers. Sleep disorders detected with the two questionnaires were significantly associated. A positive and significant association between OSAS and respectively age, time of employment, BMI, ex-smoker status, neck, waist or hip circumferences, chronic fatigue and arterial hypertension was observed. Subjective variables regarding working conditions (job interest, evaluation oforganization of work and job satisfaction) and alcohol consumption were not associated with the high risk of OSAS. Shift work (2 and 3 shifts) was not associated with the high risk of OSAS. An healthy worker effect was observed for workers who changed from shift work (2 or 3 shifts) to fixed daytime work. For them, this change to fixed daytime work was conditioned by chronic disease like hypertension and obesity. EDS was not dependent, associated or correlated with any of the occupational, personal or pathologic variables investigated in the study. In conclusion the research showed no relationship between working conditions, particularly shift work, and the high risk of OSAS, and the influence of obesity in determining the high risk of OSAS, itself a potential cardiovascular risk factor. The interest of occupational physician has been focused on introducing in health surveillance also measures of health promotion regarding sleep disorders with the aim of preserving health condition in workers.

[Availability of laboratory tools for microbiological diagnosis of lower respiratory tract infections in Italian hospitals]

To assess the availability of laboratory tools for microbiological diagnosis of lower respiratory tract infection, a survey was conducted on a sample of Italian hospital laboratories during the period April-July 2005. Overall, 261 hospitals, one third of the total Italian hospitals, were randomly selected. All these laboratories were sent a standardized questionnaire collecting information on diagnostic tools available for testing a list of bacterial, viral and fungal organisms responsible for lower respiratory tract infections. Forty eight percent of the sample completed and returned the questionnaire. A part from few pathogens such as Enterobacteria, Enterococcus Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Herpes simplex e Candida spp, for which no differences in diagnostic capacity among hospitals was found, for all the other pathogens considered, significant differences among geographical areas were found.

Why a simple model of genetic regulatory networks describes the distribution of avalanches in gene expression data

In a previous study it was shown that a simple random Boolean network model, with two input connections per node, can describe with a good approximation (with the exception of the smallest avalanches) the distribution of perturbations in gene expression levels induced by the knock-out of single genes in Saccharomyces cerevisiae. Here we address the reason why such a simple model actually works: we present a theoretical study of the distribution of avalanches and show that, in the case of a Poissonian distribution of outgoing links, their distribution is determined by the value of the Derrida exponent. This explains why the simulations based on the simple model have been effective, in spite of the unrealistic hypothesis about the number of input connections per node. Moreover, we consider here the problem of the choice of an optimal threshold for binarizing continuous data, and we show that tuning its value provides an even better agreement between model and data, valuable also in the important case of the smallest avalanches. Finally, we also discuss the choice of an optimal value of the Derrida parameter in order to match the experimental distributions: our results indicate a value slightly below the critical value 1.

Ochratoxin A occurrence and formation in Portuguese wine grapes at various stages of maturation

A total of 93 Portuguese grape samples destined for wine production were examined for the presence of ochratoxin A (OTA) and the OTA producing fungi Aspergillus carbonarius and A. niger aggregate. Samples came from 11 vineyards from four winemaking regions in the North and South of the Portuguese mainland, during the harvest seasons of 2001, 2002 and 2003. Grapes were examined at 3 maturation stages, from setting to the harvesting period, to evaluate when contamination with OTA producing fungi and OTA synthesis occur. The detection of fungi in grape samples was made by plating methods with and without surface disinfection. OTA was formed by 14% of the 650 isolates tested. Most of the OTA producing strains (96%) were isolated at harvest time. At this stage, the percentage of grape samples with OTA producing strains detected without surface disinfection was 56%. With surface disinfection, A. carbonarius was isolated from 10% of the samples. OTA was detected in grapes at the 3 maturation stages. The average OTA concentrations in 60 samples at pea berry (28 samples), early veraison (22 samples) and ripe berry (20 samples) were 263, 149 and 35 ng/kg, respectively. Experiments with an A. carbonarius strain demonstrated that OTA production differs significantly with the composition of the berries at different maturation stages (P<0.001), with a mean value of OTA production at pea berry, early veraison and ripe berry of 3402, 1530 and 22 mug/kg, respectively. The production of OTA by A. carbonarius was correlated positively and negatively with the total acidity of grapes (r(s)=0.855, P<0.001) and reducing sugars content (r(s)=-0.835, P<0.001), respectively. Our data demonstrate that OTA synthesis in grapes occurs since early maturation stages.

Fungi and ochratoxin A detected in healthy grapes for wine production

AIMS

The mycoflora of healthy grapes (i.e. without visible symptoms of rot) for wine production in Portuguese wine-making regions was assessed and its potential for ochratoxin A (OTA) production evaluated. The OTA content of grapes was also determined.

METHODS AND RESULTS

A total of 386 fungal strains were isolated by plating methods. The most frequent genera found in grapes were non-ochratoxigenic species: Cladosporium (28%), Penicillium (24%), Botrytis (13%) and Aspergillus (9%). Two OTA-producing strains were isolated, belonging to the species Aspergillus carbonarius and Aspergillus ochraceus. OTA was detected in three of four grape samples, up to 116 ng l(-1).

CONCLUSIONS

OTA is being produced in healthy berries by Aspergillus species, namely A. carbonarius, at levels below the maximum recommended limit of 2,000 ng l(-1) in wine.

SIGNIFICANCE AND IMPACT OF THE STUDY

The OTA concentration detected in healthy Portuguese grapes does not represent a risk to wine regarding the legal limit established.

Usefulness of sequential Aspergillus galactomannan antigen detection combined with early radiologic evaluation for diagnosis of invasive pulmonary aspergillosis in patients undergoing allogeneic stem cell transplantation

BACKGROUND

Early diagnosis of invasive pulmonary aspergillosis (IPA) is important as prompt treatment with antifungal drugs may increase patient survival. Our study investigated the efficiency of routine testing of the Aspergillus galactomannan antigen (AGA) test in combination with chest CT scans for IPA diagnosis.

PATIENTS AND METHODS

From February 2002 to June 2004, 74 hemato-oncologic patients undergoing allogeneic stem cell transplantation were prospectively studied with serum AGA twice weekly from admission until death or discharge and weekly afterward when possible. Chest CT scans were performed when fever of unknown origin had lasted beyond 3 days of antibacterial therapy.

RESULTS

Seven patients were classified with possible IPA and two patients, proven IPA. Fourteen patients showed positive results for AGA (OD index>or=1.0 on two subsequent sera). The sensitivity and specificity of the test were 100% and 93%, respectively; the positive and negative predictive values were 64% and 100%, respectively. All patients with possible/proven IPA showed abnormal CT signs; in four cases, imaging signs followed AGA positivity (median 5 days), whereas in five cases they preceded serologic positivity (median, 8 days). In the nine patients with IPA, antifungal therapy was promptly instituted, including lipid formulations of amphotericin B (n=5) or caspofungin (n=4). In only two of the nine patients (22%) with IPA, the primary cause of death was fungal infection.

CONCLUSIONS

The combination of AGA detection and early chest CT scans might be considered useful tools to detect minimal changes of IPA. Based on these findings, aggressive antifungal therapy should be initiated.

Chronic Chlamydia pneumoniae infection in patients with symptomatic atherothrombosis

OBJECTIVES

The aim of the present study was to search for an association between chronic Chlamydia pneumoniae infection, indicated by elevated antibody titers against the pathogen, atherothrombosis and the occurrence of arterial ischemic events.

METHODS

We studied 52 patients presenting at baseline with at least one symptomatic episode of atherothrombosis. A screening for fasting blood glucose and a lipid profile was performed on all patients who had no known history of diabetes or hypercholesterolemia.

RESULTS

The prevalence of IgG and IgA anti-C. pneumoniae antibodies at baseline was 90% (95% CI: 79-97) and 81% (67-90), respectively. Forty-two of the 52 patients (81%) experienced a new arterial ischemic event after a mean follow-up of 9 years [heart: 19 (37%); brain: 12 (23%); lower limbs: 8 (15%); and other: 13 (25%)]. Occurrence of a new arterial ischemic event was related to age (p=0.003), sex (p=0.009), and tobacco smoking (p=0.06). Prevalences of IgA and IgG anti-C. pneumoniae were significantly higher in patients with atherothrombosis at baseline than that in controls.

CONCLUSION

Our study confirmed the links between C. pneumoniae and atherothrombosis. However, neither IgA nor IgG antibodies for C. pneumoniae was a significant predictive factor for new ischemic arterial events in patients with atherothrombosis.

Mouse models of transforming growth factor beta impact in breast development and cancer

It is now recognized that transforming growth factor beta (TGF-beta) is an important factor that regulates normal breast development as well as breast cancer. Genetically engineered mouse models have been used to determine the role and mechanism of TGF-beta action in normal development and diseases of the breast. Using these models, it has been determined that TGF-beta regulates many steps of normal mammary gland development including branching morphogenesis, functional differentiation, cell-lineage decisions, and involution. Effects of TGF-beta on normal development are mediated through signaling in both the epithelial and stromal compartments. In cancer, mouse models have indicated that TGF-beta has biphasic effects on tumor progression, acting as a tumor suppressor in early stages of cancer and promoting invasion and metastasis at later stages. In addition, TGF-beta may play a role in tumor progression through effects on the microenvironment. Recently, experiments in several mouse models have suggested that antagonism of TGF-beta signaling may provide a therapeutic target for late-stage breast cancer, blocking metastasis without detrimental side effects. In the future, genetically altered mice will be used to establish models of human breast disease providing opportunities to test strategies for disease prevention and treatment.

Comparisons of activity measurements with radionuclide calibrators—A tool for quality assessment and improvement in nuclear medicine

A national program of ongoing comparisons for assaying gamma-emitting radiopharmaceuticals for amount of radioactivity using radionuclide calibrators was begun in 2000. Nuclides of the most wide-spread use in Cuban nuclear medicine, 131I, 201Tl and (99m)Tc, as well as two measurement geometries, glass vials and plastic syringes, were employed. In this paper, the participants' performance is assessed by mean of a statistical analysis of the reported data. Performance tables have been obtained and a chi2 statistic is calculated from observed and expected frequencies, with the aim of testing the hypothesis about the independence of some characteristics of the comparison results, at a significance level alpha=0.05. The proportion of satisfactory results in the years 2002-2004 were found to be at the same level, but higher than in 2000. It reveals an improvement of the measurement quality since 2002. The causes of improvement were investigated using the statistical treatment of several data available as supplementary information.

Hospital-acquired infections in Italy: a region wide prevalence study

Between October and December 2000, a region-wide prevalence study of hospital-acquired infections (HAI) was conducted in all public hospitals (59 facilities with ca. 16000 beds; 560000 admission yearly) in Piemonte Region, Italy, and in the one hospital of the neighbouring autonomous region of Valle d'Aosta. The study population comprised a total of 9467 patients hospitalized for at least 24 h. The prevalence of HAI was 7.84%, with marked differences in prevalence among the participating hospitals (range: 0-47.8%). The higher relative frequency of urinary tract infections (UTI; 52.7%) was due to the inclusion of urine cultures obtained on the day of the study from asymptomatic UTI in catheterized patients. A significant correlation was found with major risk factors related to medical procedures (urinary catheter, mechanical ventilation, surgical drainage, intravascular catheters). Patients with HAI were found to be older and to have a greater mean length of stay in hospital. Multiple logistic regression analyses showed that lack of independence, indwelling urinary catheter and mechanical ventilation were the risk factors more significantly associated with HAI. The use of antibiotics, in particular prophylactic agents used in surgery (cephalosporins, glycopeptides), provided an incentive for corrective intervention in antibiotic administration and in training of healthcare workers.

Further lowering of muscle lipid oxidative capacity in obese subjects after biliopancreatic diversion

A reduced lipid oxidative capacity is considered a risk factor for the development of obesity, but a further impairment of lipid oxidative capacity is observed after weight loss. We aimed to define the mechanisms underlying this phenomenon in skeletal muscle and in particular to study the mitochondrial and peroxisomal lipid oxidative pathways. Thus we measured intramyocellular triglyceride content (IMTG) and the expression of genes of lipid oxidation [peroxisome proliferator-activated receptor-alpha, carnitine palmitoyltransferase 1B, and acyl-coenzyme A (acyl-CoA) oxidase 1] and synthesis (acetyl-CoA carboxylase B) using RT-PCR analysis in muscle biopsies of morbidly obese patients before and after biliopancreatic diversion. Weight reduction significantly decreased IMTG while increasing insulin sensitivity, measured by euglycemic hyperinsulinemic clamp. Moreover, an increase in glucose and a decline in lipid oxidation, as assessed by respiratory chamber, were observed. Weight loss reduced the expression of peroxisome proliferator-activated receptor-alpha (-46.7%), carnitine palmitoyltransferase 1B (-43.1%), acyl-CoA oxidase 1 (-37.8%), and acetyl-CoA carboxylase B (-48.7%). Our results indicate that a defect of both peroxisomal and mitochondrial oxidative pathways at the muscular level may contribute to the reduced fat oxidation in obese subjects after biliopancreatic diversion. They also suggest that a depression of the de novo lipogenesis may account for IMTG depletion.

Genetic network models and statistical properties of gene expression data in knock-out experiments

It is shown here how gene knock-out experiments can be simulated in Random Boolean Networks (RBN), which are well-known simplified models of genetic networks. The results of the simulations are presented and compared with those of actual experiments in S. cerevisiae. RBN with two incoming links per node have been considered, and the Boolean functions have been chosen at random among the set of so-called canalizing functions. Genes are knocked-out (i.e. silenced) one at a time, and the variations in the expression levels of the other genes, with respect to the unperturbed case, are considered. Two important variables are defined: (i) avalanches, which measure the size of the perturbation generated by knocking out a single gene, and (ii) susceptibilities, which measure how often the expression of a given gene is modified in these experiments. A remarkable observation is that the distributions of avalanches and susceptibilities are very robust, i.e. they are very similar in different random networks; this should be contrasted with the distribution of other variables that show a high variance in RBN. Moreover, the distribution of avalanches and susceptibilities of the RBN models are close to those observed in actual experiments performed with S. cerevisiae, where the changes in gene expression levels have been recorded with DNA microarrays. These findings suggest that these distributions might be "generic" properties, common to a wide range of genetic models and real genetic networks. The importance of such generic properties is discussed.