Roles of the primary cilium component Polaris in synchondrosis development

Primary cilia regulate several developmental processes and mediate hedgehog signaling. To study their roles in cranial base development, we created conditional mouse mutants deficient in Polaris, a critical primary cilium component, in cartilage. Mutant post-natal cranial bases were deformed, and their synchondrosis growth plates were disorganized. Expression of Indian hedgehog, Patched-1, collagen X, and MMP-13 was reduced and accompanied by decreases in endochondral bone. Interestingly, there was excessive intramembranous ossification along the perichondrium, accompanied by excessive Patched-1 expression, suggesting that Ihh distribution was wider and responsible for such excessive response. Indeed, expression of heparan sulfate proteoglycans (HS-PGs), normally involved in restricting hedgehog distribution, was barely detectable in mutant synchondroses. Analyses of the data provides further evidence for the essential roles of primary cilia and hedgehog signaling in cranial base development and chondrocyte maturation, and point to a close interdependence between cilia and HS-PGs to delimit targets of hedgehog action in synchondroses.

A nonlinear lumped parameters model to analyze the dynamics of venous reflux

The aim of this work is to formulate a lumped parameters model of the venous tree of the lower limbs in order to study the effects and the possible clinical treatments for Chronic Venous Insufficiency (CVI). CVI is a pathology characterized by an important socio-economic impact due to its relevant prevalence, the costs for its diagnosis and treatment being more frequently widespread among the working population. The planning of haemodynamic surgical operations is critical to treat a pathological pattern of venous blood flow; such planning, in turn, depends on the right analysis of the possible consequences of flow modification. To this regard, the blood flow correction allows to solve the most important venous pathologies, in order to guarantee the restoration of normal blood flow by means of proper modifications of the venous tree. The developed model preserves the geometry of the venous network and considers some non linear resistive and capacitive effects. In fact, the study of the variability of some parameters (i.e. vessel radius) is very important to allow a correct diagnosis of vascular diseases. This variability causes a non linear behaviour of resistance and compliance effects. With the aid of the developed model we evaluate the time profile of blood velocity, flow and pressure in the entire venous network, both in physiological and pathological cases. The obtained results are discussed in comparison with available experimental data.

[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.

Comparisons of activity measurements with radionuclide calibrators

The correct administration to a patient of the prescribed activity of a radiopharmaceutical is an important factor to ensure the confidence in the diagnosis or the therapeutic efficiency, while at the same time keeping the unnecessary human exposure as low as possible. Comparisons of activity measurements for 131I, 201Tl and 99mTc with radionuclide calibrators were organized the first time in Cuba during 2002 with the aim of obtaining information about the quality of administration of radiopharmaceuticals. Ten Cuban nuclear medicine departments and the laboratories involved in the production of these kinds of compounds participated in the comparison runs. The results presented in this paper facilitated the identification of several problems and initiated corrective actions. In addition, they indicate the necessity of establishing Quality Systems in nuclear medicine in Cuba.

Infectious complications following nonmyeloablative allogeneic hematopoietic stem cell transplantation

Nonmyeloablative hematopoietic stem cell transplantation (NST) has been explored in hematological malignancies and solid tumors in an attempt to minimize treatment-related toxicity. Whether this approach is associated with reduced risk of infectious complications is unclear. The aim of the current study was to evaluate the infectious complications in a series of 32 consecutive adult patients who received NST at our institution. Peripheral blood stem cell grafts (n=30) or marrow grafts (n=2) were infused from human leukocyte antibody (HLA)-matched sibling (n=30), partially matched related (n=1), or unrelated (n=1) donors. Neutropenia developed in two-thirds of patients and lasted 16 days. Acute graft-versus-host disease (GVHD) grade II to IV was observed in 25% of patients, whereas 35% of patients had signs of extensive chronic GVHD. Twenty-two patients (69%) had at least one significant infectious episode. Bacteremia occurred in 19% of patients (n=5 gram-positive, n=1 gram-negative microorganisms). Cytomegalovirus (CMV) infection was observed in 10 out of 28 (36%) evaluable patients; 4 of these had recurrent or persistent CMV antigenemia requiring a second-line treatment, but eventually the viremia cleared. No patients experienced CMV disease. Fungal infections were documented in five (16%) patients, comprising invasive fungal infections in two cases and mucosal fungal infections in three. Four patients died of transplant-related causes, and three of these died before day +100. Infection was considered the primary cause of death in one patient (pulmonary aspergillosis) and contributed to death in another two. The actuarial probability of nonrelapse mortality at 100 days was 10% (95% confidence interval, 3-26%). Our preliminary results suggest that NST is associated to a low incidence of bacteremia or fungal and viral infections. Whether these findings would translate into an improved overall survival needs to be confirmed in larger prospective studies.

[Our experience with treatment of varicocele in a day-surgery protocol]

In the last few years the increasing interest for non-invasive operating techniques has allowed to reevaluate the sublinguinal varicocelectomy surgical technique for idiopathic varicocele surgical treatment. During the years 1998-2001, 29 patients have been operated on sub-inguinal varicocelectomy (14 patients were suffering from idiopathic varicocele of third grade, 11 of second grade, 3 of first grade, and 1 subclinical). Out of the 29 patients, only 10 were unable to procreate. All patients were operated under local anesthesia and discharged the same day (day-surgery). Owing to Authors' experience, the sublinguinal varicocelectomy by optical magnifying devices represents the "gold standard" in the idiopathic varicocele treatment because it allows to minimize relapsing rates, to limit post-operation complications, to improve the reproductive faculty of seminal fluid both qualitatively and quantitatively, to cut patient's operating costs significantly, to keep the operation time within acceptable limits, and to be easily learned and carried out.

[Some remarks on the management of liver donor]

We evaluated 481 liver donors in order to assess the incidence of positive cultures on samples obtained before harvesting, at harvesting and on preservation fluid; to determine factors related to positive cultures in the donor; to analyse the bacterial and fungal transmission from donor to recipient; to verify the influence of donor culture positivity on graft and patient survival. Cultures were positive in 232 of 481 (48%) donors. Bacteremia was present in 101 of 481 (20%) donors. Intensive care length of stay was significantly longer in culture-positive donors. A Gram-negative bacteria transmission from the infected donor to the graft recipient was proven in 1 case. No differences in 1-year survival and retransplantation rates were found between patients receiving livers from culture-positive or negative donors. In conclusion, even if rare, donor to host infection transmission is proven. Extended criteria for organ procurement may explain the high number of culture-positive donors we report. Careful microbiological surveillance and treatment can reduce the clinical negative impact on recipient outcome.

A procedure for the standardization of gamma reference sources for quality assurance in activity measurements of radiopharmaceuticals

A simplified procedure for the standardization of gamma reference sources, for use in quality assurance of activity measurements during production and application of radiopharmaceuticals in Cuban nuclear medicine laboratories, is described. The method is based on the reliable achievement of consistent measurements by both gamma-spectrometry and ionization chamber techniques, and allows to obtain reference sources with uncertainties lower than 2%. Experimental setup, validation procedure and typical results obtained for 99mTc, 131I, 201Tl and 153Sm are described and discussed. The method will serve also as a secondary reference system for radioactivity measurements in the country.

Changes in FAT/CD36, UCP2, UCP3 and GLUT4 gene expression during lipid infusion in rat skeletal and heart muscle

OBJECTIVE

It has been reported that an increased availability of free fatty acids (NEFA) not only interferes with glucose utilization in insulin-dependent tissues, but may also result in an uncoupling effect of heart metabolism. We aimed therefore to investigate the effect of an increased availability of NEFA on gene expression of proteins involved in transmembrane fatty acid (FAT/CD36) and glucose (GLUT4) transport and of the uncoupling proteins UCP2 and 3 at the heart and skeletal muscle level.

STUDY DESIGN

Euglycemic hyperinsulinemic clamp was performed after 24 h Intralipid(R) plus heparin or saline infusion in lean Zucker rats. Skeletal and heart muscle glucose utilization was calculated by 2-deoxy-[1-(3)H]-D-glucose technique. Quantification of FAT/CD36, GLUT4, UCP2 and UCP3 mRNAs was obtained by Northern blot analysis or RT-PCR.

RESULTS

In Intralipid(R) plus heparin infused animals a significant decrease in insulin-mediated glucose uptake was observed both in the heart (22.62+/-2.04 vs 10.37+/-2.33 ng/mg/min; P<0.01) and in soleus muscle (13.46+/-1.53 vs 6.84+/-2.58 ng/mg/min; P<0.05). FAT/CD36 mRNA was significantly increased in skeletal muscle tissue (+117.4+/-16.3%, P<0.05), while no differences were found at the heart level in respect to saline infused rats. A clear decrease of GLUT4 mRNA was observed in both tissues. The 24 h infusion of fat emulsion resulted in a clear enhancement of UCP2 and UCP3 mRNA levels in the heart (99.5+/-15.3 and 80+/-4%) and in the skeletal muscle (291.5+/-24.7 and 146.9+/-12.7%).

CONCLUSIONS

As a result of the increased availability of NEFA, FAT/CD36 gene expression increases in skeletal muscle, but not at the heart level. The augmented lipid fuel supply is responsible for the depression of insulin-mediated glucose transport and for the increase of UCP2 and 3 gene expression in both skeletal and heart muscle.

Developmental and TGF-beta-mediated regulation of Ank mRNA expression in cartilage and bone

OBJECTIVES

Ank encodes a transmembrane protein that is involved in pyrophosphate (PPi) transport and mutations in the Ank gene have been associated with pathological mineralization in cartilage and bone. To understand how Ank works in normal skeletal development it is also important to know which cells within the developing skeleton express Ank. To this end, we examined the expression pattern of Ank mRNA during mouse embryonic development as well as in mouse hind limb joints with emphasis on the period when articular cartilage forms. Since it was previously shown that TGF-beta regulates PPi transport in cells in culture, we also tested the hypothesis that TGF-beta regulates Ank expression.

METHODS

The localization of Ank mRNA was determined by radioactive in situ hybridization in E15.5 and E17.5 mouse embryos as well as in 1 and 3 week post-natal mice. Ank expression was compared to that of other cartilage markers. In situ hybridization and semi-quantitative RT-PCR were used to determine the effects of TGF-beta on Ank expression in metatarsal organ cultures.

RESULTS

Ank expression was detected at high levels at sites of both endochondral and intramembranous bone development. In endochondral bones, expression was detected in a subset of hypertrophic cells at ossification centers. Expression was also detected in osteogenic/chondrogenic cells of the perichondrium/periosteum lining the metaphysis, an area associated with the formation and extension of the bone collar. High levels of expression were also detected in non-mineralized tissues of the skeletal system including tendons and the superficial layer of the articular cartilage. Treatment with TGF-beta resulted in an approximately four-fold induction of Ank mRNA in prehypertrophic chondrocytes and perichondrium of metatarsal cultures.

CONCLUSIONS

The expression pattern of Ank suggests an important role both in inhibiting and regulating mineralization in the developing skeletal system. In addition, TGF-beta1 is able to mediate Ank mRNA expression in chondrocytes suggesting a possible role for TGF-beta and Ank in the regulation of normal mineralization.

Signaling to the epithelium is not sufficient to mediate all of the effects of transforming growth factor beta and bone morphogenetic protein 4 on murine embryonic lung development

Many studies have suggested that transforming growth factor beta (TGF-beta) and bone morphogenetic protein 4 (Bmp4) regulate early development of the lung. In this study, administration of growth factors directly into the lumen of lungs grown in organ culture was used to limit their activity to the epithelium and test the hypothesis that signaling to the epithelium is sufficient to mediate the known effects of TGF-beta and BMP-4 on early lung development. Addition of TGF-beta1, beta2, or beta3 to the medium surrounding lungs grown in organ culture resulted in decreased branching, reduced cell proliferation, accumulation of alpha-smooth muscle actin protein (alpha-SMA) in the mesenchyme, and decreased expression of a marker for respiratory epithelium, surfactant protein-C (Sp-C). When TGF-beta1 was restricted to the epithelium, accumulation of alpha-SMA and inhibition of Sp-C expression were not observed but branching and proliferation were inhibited. In contrast, branching was not inhibited in lungs where TGF-beta2 or TGF-beta3 were restricted to the epithelium suggesting differences in the mechanism of signaling by TGF-beta1, TGF-beta2 or TGF -beta3 in lung. Addition of Bmp4 to the medium surrounding lungs grown in organ culture stimulated cell proliferation and branching morphogenesis; however, direct injection of Bmp4 into the lung lumen had no effect on proliferation or branching. Based on these data and data from mesenchyme-free cultures, we propose that the mesenchyme influences growth factor signaling in the lung.

An improved metabolic calibrator for stress test equipment: protocol for its clinical utilization

In previous articles, the technical specifications, validation and clinical applicability of a new metabolic calibrator for stress test apparatuses were described. However no indication was given of a basic protocol for the current clinical practice. Here we present an organised check system to satisfy this aim. A method for the exhaustive evaluation of the technical reliability of the metabolic instruments is presented together with the proposal of a uniform simulation approach to organise checks on-line of the apparatuses' ability to follow correctly the various test phases (protocol). Examples of recordings of checks using the standardised approach are shown. The method seems to be very effective. Every operation is computer directed.

The perichondrium plays an important role in mediating the effects of TGF-beta1 on endochondral bone formation

Endochondral bone formation is complex and requires the coordination of signals from several factors and multiple cell types. Thus, chondrocyte differentiation is regulated by factors synthesized by both chondrocytes and cells in the perichondrium. Previously, we showed that expression of a dominant-negative form of the transforming growth factor beta (TGF-beta) type II receptor in perichondrium/periosteum resulted in increased hypertrophic differentiation in growth plate chondrocytes, suggesting a role for TGF-beta signaling to the perichondrium in limiting terminal differentiation in vivo. Using an organ culture model, we later demonstrated that TGF-beta1 inhibits chondrocyte proliferation and hypertrophic differentiation by two separate mechanisms. Inhibition of hypertrophic differentiation was shown to be dependent on Parathyroid hormone-related peptide (PTHrP) and expression of PTHrP mRNA was stimulated in the perichondrium after treatment with TGF-beta1. In this report, the hypothesis that the perichondrium is required for the effects of TGF-beta1 on growth and/or hypertrophic differentiation in mouse metatarsal organ cultures is tested. Treatment with TGF-beta1 inhibited expression of type X collagen mRNA in metatarsal cultures with the perichondrium intact. In contrast, hypertrophic differentiation as measured by expression of Type X collagen was not inhibited by TGF-beta1 in perichondrium-free cultures. TGF-beta1 added to intact cultures inhibited BrdU incorporation in chondrocytes and increased incorporation in the perichondrium; however, TGF-beta1 treatment stimulated chondrocyte proliferation in metatarsals from which the perichondrium had been enzymatically removed. These results suggest that the TGF-beta1-mediated regulation of both chondrocyte proliferation and hypertrophic differentiation is dependent upon the perichondrium. Thus, one or several factors from the perichondrium might mediate the way chondrocytes respond to TGF-beta1.

Preferential channeling of energy fuels toward fat rather than muscle during high free fatty acid availability in rats

The preferential channeling of different fuels to fat and changes in the transcription profile of adipose tissue and skeletal muscle are poorly understood processes involved in the pathogenesis of obesity and insulin resistance. Carbohydrate and lipid metabolism may play relevant roles in this context. Freely moving lean Zucker rats received 3- and 24-h infusions of Intralipid (Pharmacia and Upjohn, Milan, Italy) plus heparin, or saline plus heparin, to evaluate how an increase in free fatty acids (nonesterified fatty acid [NEFA]) modulates fat tissue and skeletal muscle gene expression and thus influences fuel partitioning. Glucose uptake was determined in various tissues at the end of the infusion period by means of the 2-deoxy-[1-3H]-D-glucose technique after a euglycemic-hyperinsulinemic clamp: high NEFA levels markedly decreased insulin-mediated glucose uptake in red fiber-type muscles but enhanced glucose utilization in visceral fat. Using reverse transcriptase-polymerase chain reaction and Northern blotting analyses, the mRNA expression of fatty acid translocase (FAT)/CD36, GLUT4, tumor necrosis factor (TNF)-alpha, peroxisome proliferator-activated receptor (PPAR)-gamma, leptin, uncoupling protein (UCP)-2, and UCP-3 was investigated in different fat depots and skeletal muscles before and after the study infusions. GLUT4 mRNA levels significantly decreased (by approximately 25%) in red fiber-type muscle (soleus) and increased (by approximately 45%) in visceral adipose tissue. Furthermore, there were marked increases in FAT/CD36, TNF-alpha, PPAR-gamma, leptin, UCP2, and UCP3 mRNA levels in the visceral fat and muscle of the treated animals in comparison with those measured in the saline-treated animals. These data suggest that the in vivo gene expression of FAT/CD36, GLUT4, TNF-alpha, PPAR-gamma, leptin, UCP2, and UCP3 in visceral fat and red fiber-type muscle are differently regulated by circulating lipids and that selective insulin resistance seems to favor, at least in part, a prevention of fat accumulation in tissues not primarily destined for fat storage, thus contributing to increased adiposity and the development of a prediabetic syndrome.

Antagonistic effects of TGFbeta1 and BMP-6 on skin keratinocyte differentiation

Several members of the transforming growth factor beta (TGFbeta) superfamily are expressed in the developing murine epidermis. Among these are TGFbeta1, which is found in the basal layer, and bone morphogenetic protein (BMP)-6, located in the suprabasal layers. Although the role of TGFbeta in cell growth has been studied extensively, little is known about the effects of these factors on keratinocyte differentiation. This study demonstrates that BMP-6 acts to positively regulate the differentiation of primary skin keratinocytes grown in culture. In contrast, TGFbeta1 antagonizes keratinocyte differentiation blocking the upregulation of keratin markers by BMP-6. We show that the effects of BMP-6 on expression of keratin 1 (K1), a marker of differentiation, requires signaling through the Smad pathway. In addition, regulation of K1 levels by BMP-6 is modulated by the SEK signaling pathway. This suggests that regulation of keratinocyte differentiation by BMP-6 involves multiple signaling systems.

Substrate competition and insulin action in animal models

Increased basal plasma FFA and lactate concentrations are often present in obesity and may deeply affect insulin action. The inhibition of glucose transport or phosphorylation is thought to be involved in this phenomenon, but the molecular mechanisms on the basis are still unknown. In our laboratory we observed that a chronic infusion of Intralipid plus heparin in rats significantly decreased the insulin dependent-glucose uptake, as well as GLUT4 gene expression in muscular tissue. On the other hand it has been shown that an enhanced plasma lactate concentration may increase insulin secretion and hepatic insulin clearance. Moreover we observed that chronic hyperlactatemia in rats is able to decrease glucose uptake in muscles, while reducing GLUT4 mRNA and protein in the same tissues. In obesity, lactate and FFA overproduction from visceral fat may therefore play a synergic role in reducing insulin sensitivity.

[Refractory angina treated by spinal cord stimulation. The results of a long-term follow-up]

INTRODUCTION AND OBJECTIVES

The quality of life in patients with refractory angina has been shown to improve dramatically with spinal cord stimulation because of its beneficial results. The aim of this study was to assess the long-term morbimortality of this technique of spinal cord stimulation in the long term.

PATIENTS AND METHODS

41 patients with refractory angina and treated with spinal cord stimulation were included. Median follow-up was 31.0 [12.0-42.5] months, and total follow-up was 1,236 months.

RESULTS

Annual number of admissions per patient year were dramatically reduced after spinal cord stimulation (2.31 vs. 0.28). Patients that died during follow-up had a 3-fold increase rate of admissions than patients that survived (0.37 vs. 0.19). However, patients that died during follow-up also had a lower admission rate after spinal cord stimulation (2.03 vs. 0.37). Overall mortality was 9.7%/year; cardiac mortality was 7.7%/year. Both figures are not different from those of other groups of patients with similar anatomical characteristics of coronary artery disease severity without spinal cord stimulation. Complications of this treatment were minimal (we only observed an early post implantation infection and a battery extrusion, without any complications with electrodes). The outcome was similar in patients with subacute unstable refractory angina or stable angina.

CONCLUSIONS

Spinal cord stimulation can be considered a safe and effective alternative treatment of refractory angina. Long-term morbidity is low, and mortality is not higher than the expected in this group of patients.

Seasonal changes of zinc, copper, and iron in gilthead sea bream (Sparus aurata) fed fortified diets

Four groups of gilthead sea bream (Sparus aurata) were fed diets with additional metal contents: a basal diet (diet A) contained Zn at 60.9 +/- 1.9 mg/kg diet, Cu at 3.9 +/- 0.9 mg/kg diet, and Fe at 138.3 +/- 6.8 mg/kg diet; the other diets were supplemented with copper (20 mg/kg, diet B), iron (100 mg/kg, diet C), or zinc (300 mg/kg, diet D). Two consecutive year-classes (0+ and 1+ age fish) from the same parent stock were examined. Several fish tissues were analyzed for metal contents in five different periods of each year in order to determine (1) the sensitivity of certain tissues as indicators of trace element metabolism and (2) possible seasonal variations. Growth data were similar for gilthead sea bream fed the basal diet and the metal-fortified diets. Mineral concentrations in tissues were found to be little affected by the dietary supplementation of trace elements, suggesting an efficient homeostatic control of these three metal concentrations. Tissues involved in metal metabolism (e.g., liver, kidney, gills) presented greater variations between minimum and maximum values with respect to other tissues (e.g., brain, muscle, eye). Seasonal variations were observed during the 2 yr of this study and were especially evident for zinc and copper concentrations in the liver. The overall pattern of metal variations showed a decreasing trend during the 2 yr. Results from this study indicate that (1) trace element concentrations in fish tissues vary with age and life cycle and (2) trace element requirements may vary in function of age and life cycle.

Improved respiratory CO2-He analysis for peripheral airways impairment detection. Utilization possibilities of a new computerized system in preventive medicine studies

The authors illustrate the application possibilities in occupational and preventive medicine of a recently computerized system for the evaluation of peripheral ventilatory non-homogeneities with or without alveolar air trapping. The method consists of an improved individual multiple breath by breath test utilizing the analysis of the respiratory gases CO2 and He. It is based on the results of previous experimental measurements performed simultaneously in different pulmonary sectors an depends on the technical possibility of signalizing out-of-phase expired CO2-He mixtures at the end of the inert gas clearance when in subjects with peripheral respiratory disorders the two gases CO2 and He arrive at the mouth at different times, during the same expiration and cause different, opposite signals. The applied physiological reliability of the measurements was experimentally verified, their technical specificity was recently established. The use of a new computerized system allows actually automatic, on-line measurements under the control of the operator, following a standardized method. The resolution power of the signals is very high. The calculation of the results is performed by the software. The system is easy to transport and can be used in the field for screening on large groups of persons in preventive medicine inquiries and during occupational medicine checks. Quite recently it has been usefully employed during an investigation on 200 subjects, occupationally exposed (policemen of the city traffic department of the town of Bologna).

Seasonal dependence of cadmium accumulation and Cd-binding proteins in Mytilus galloprovincialis exposed to cadmium

At different periods of the year specimens of Mytilus galloprovincialis were exposed to 0.5 microg Cd/ml seawater for 7 days. Concentrations of trace elements (Cd, Zn, Cu and Fe) and Cd-binding proteins in gills, viscera, muscle and mantle were determined after 1 weeks exposure. Cadmium accumulation was higher in May and June and was tissue dependent; it was highest in the gills and decreased in the order: gills > viscera > mantle and adductor muscle. Significant seasonal variations of zinc, copper and iron, were also found, in both exposed and control molluscs. The percentage of Cd distribution between cytosol and pellet changed during the year; a clear shift from the particulate fractions to the cytosolic fractions was measured during May and June, especially in the gills. Metallothionein (MT) was the main ligand responsible for Cd accumulation, and this protein reached a maximum between May and June. Inclusion of mercaptoethanol during the purification procedure was found to improve MT isolation by gel chromatography. In the absence of mercaptoethanol, MT showed polymerization patterns which were season dependent and temperature independent, whereas its concentration was increased in mussels kept at higher temperature.

Parathyroid hormone-related peptide (PTHrP)-dependent and -independent effects of transforming growth factor beta (TGF-beta) on endochondral bone formation

Previously, we showed that expression of a dominant-negative form of the transforming growth factor beta (TGF-beta) type II receptor in skeletal tissue resulted in increased hypertrophic differentiation in growth plate and articular chondrocytes, suggesting a role for TGF-beta in limiting terminal differentiation in vivo. Parathyroid hormone-related peptide (PTHrP) has also been demonstrated to regulate chondrocyte differentiation in vivo. Mice with targeted deletion of the PTHrP gene demonstrate increased endochondral bone formation, and misexpression of PTHrP in cartilage results in delayed bone formation due to slowed conversion of proliferative chondrocytes into hypertrophic chondrocytes. Since the development of skeletal elements requires the coordination of signals from several sources, this report tests the hypothesis that TGF-beta and PTHrP act in a common signal cascade to regulate endochondral bone formation. Mouse embryonic metatarsal bone rudiments grown in organ culture were used to demonstrate that TGF-beta inhibits several stages of endochondral bone formation, including chondrocyte proliferation, hypertrophic differentiation, and matrix mineralization. Treatment with TGF-beta1 also stimulated the expression of PTHrP mRNA. PTHrP added to cultures inhibited hypertrophic differentiation and matrix mineralization but did not affect cell proliferation. Furthermore, terminal differentiation was not inhibited by TGF-beta in metatarsal rudiments from PTHrP-null embryos; however, growth and matrix mineralization were still inhibited. The data support the model that TGF-beta acts upstream of PTHrP to regulate the rate of hypertrophic differentiation and suggest that TGF-beta has both PTHrP-dependent and PTHrP-independent effects on endochondral bone formation.

Hyperlactatemia reduces muscle glucose uptake and GLUT-4 mRNA while increasing (E1alpha)PDH gene expression in rat

An increased basal plasma lactate concentration is present in many physiological and pathological conditions, including obesity and diabetes. We previously demonstrated that acute lactate infusion in rats produced a decrease in overall glucose uptake. The present study was carried out to further investigate the effect of lactate on glucose transport and utilization in skeletal muscle. In chronically catheterized rats, a 24-h sodium lactate or bicarbonate infusion was performed. To study glucose uptake in muscle, a bolus of 2-deoxy-[3H]glucose was injected in basal condition and during euglycemic-hyperinsulinemic clamp. Our results show that hyperlactatemia decreased glucose uptake in muscles (i.e., red quadriceps; P < 0.05). Moreover in red muscles, both GLUT-4 mRNA (-30% in red quadriceps and -60% in soleus; P < 0.025) and protein (-40% in red quadriceps; P < 0.05) were decreased, whereas the (E1alpha)pyruvate dehydrogenase (PDH) mRNA was increased (+40% in red quadriceps; P < 0.001) in lactate-infused animals. PDH protein was also increased (4-fold in red gastrocnemius and 2-fold in red quadriceps). These results indicate that chronic hyperlactatemia reduces glucose uptake by affecting the expression of genes involved in glucose metabolism in muscle, suggesting a role for lactate in the development of insulin resistance.

Overexpression of a kinase-deficient transforming growth factor-beta type II receptor in mouse mammary stroma results in increased epithelial branching

Members of the transforming growth factor-beta (TGF-beta) superfamily signal through heteromeric type I and type II serine/threonine kinase receptors. Transgenic mice that overexpress a dominant-negative mutation of the TGF-beta type II receptor (DNIIR) under the control of a metallothionein-derived promoter (MT-DNIIR) were used to determine the role of endogenous TGF-betas in the developing mammary gland. The expression of the dominant-negative receptor was induced with zinc and was primarily localized to the stroma underlying the ductal epithelium in the mammary glands of virgin transgenic mice from two separate mouse lines. In MT-DNIIR virgin females treated with zinc, there was an increase in lateral branching of the ductal epithelium. We tested the hypothesis that expression of the dominant-negative receptor may alter expression of genes that are expressed in the stroma and regulated by TGF-betas, potentially resulting in the increased lateral branching seen in the MT-DNIIR mammary glands. The expression of hepatocyte growth factor mRNA was increased in mammary glands from transgenic animals relative to the wild-type controls, suggesting that this factor may play a role in TGF-beta-mediated regulation of lateral branching. Loss of responsiveness to TGF-betas in the mammary stroma resulted in increased branching in mammary epithelium, suggesting that TGF-betas play an important role in the stromal-epithelial interactions required for branching morphogenesis.