Carcinogenicity prediction using the index of ideality of correlation.

Carcinogenicity testing is necessary to protect human health and comply with regulations, but testing it with the traditionally used two-year rodent studies is time-consuming and expensive. In certain cases, such as for impurities, alternative methods may be convenient. Thus there is an urgent need for alternative approaches for reliable and robust assessments of carcinogenicity. The Monte Carlo technique with CORAL software is a tool to tackle this task for unknown compounds using available experimental data for a representative set of compounds. The models can be constructed with the simplified molecular input line entry system without additional physicochemical descriptors. We describe here a model based on a data set of 1167 substances. Matthew's correlation coefficient values for calibration and validation sets are 0.747 and 0.577, respectively. Double bonds between carbon atoms and double bonds of oxygen atoms are the molecular features that indicate the carcinogenic potential of a compound.

Seroprevalence and incidence of Toxoplasma gondii infection in the Legnano area of Italy.

The decreasing prevalence of anti-Toxoplasma antibodies in Europe has re-opened the question of the appropriateness of serological screening during pregnancy. A study of 3426 pregnant women, resident in the Legnano area of Italy, revealed that the IgG seroprevalence according to ELISA was 21.5%, and that of IgM according to ELISA and enzyme-linked fluorescent assay was 1.2% and 0.9%, respectively. The incidence of infection, estimated on the basis of IgG avidity, was 0.9%. These results confirm a decrease in the prevalence of IgG, but indicate a high incidence of infection, thus suggesting that screening for anti-Toxoplasma antibodies during pregnancy should be maintained.

Molecular and biochemical analysis of RET/PTC4, a novel oncogenic rearrangement between RET and ELE1 genes, in a post-Chernobyl papillary thyroid cancer.

A post-Chernobyl papillary thyroid cancer, displaying a novel ELE1/RET oncogenic rearrangement with an anomalous fusion transcript, was molecularly characterized. In spite of the presence of a normal breakpoint in exon 5 of the activating ELE1 gene, the sequence of the rearranged genomic DNA showed a previously unreported intra-exonic breakpoint in the RET protooncogene. As a consequence, a cDNA sequence 93 nucleotides larger than the regular one, and with the exon 5 of ELE1 joined to exon 11 instead of exon 12 of RET, is formed. To characterize the product of this new oncogenic ELE1/RET rearrangement, here designated as RET/PTC4, we performed an immunoprecipitation and Western blot analysis on cell extracts from NIH3T3 transfectants. The results showed the presence of two isoforms of the chimeric protein, displaying a constitutive tyrosine phosphorylation. As expected, the molecular weight of this protein was higher than that of RET/ PTC3 protein (p80 and p85, instead of p76 and p81). Previous reports, from our and other laboratories, showed that post-Chernobyl papillary thyroid carcinomas are characterized by a high frequency (about 60%) of RET oncogenic rearrangements (Fugazzola et al., 1995; Klugbauer et al., 1995; Ito et al., 1994). These events predominantly involve ELE1 activating sequence, thus producing RET/PTC3 oncogene (Fugazzola et al., 1995; Klugbauer et al., 1995). Hence, this elevated frequency of RET rearrangements could increase the probability of selecting unusual events as that here described. Alternatively, targeted radiation effects could be responsible for the atypical RET rearrangement producing RET/PTC4 oncogene.

The Glu632-Leu633 deletion in cysteine rich domain of Ret induces constitutive dimerization and alters the processing of the receptor protein.

Mutations of the RET gene, encoding a receptor tyrosine kinase, have been associated with the inherited cancer syndromes MEN 2A and MEN 2B. They have also further been associated with both familial and sporadic medullary thyroid carcinomas. Missense mutations affecting cysteine residues within the extracellular domain of the receptor causes constitutive tyrosine kinase activation through the formation of disulfide-bonded homodimers. We have recently reported that a somatic 6 bp in-frame deletion, originally coding for Glu632-Leu633, potently activates the RET gene. This activation is increased with respect to the frequent MEN 2A-associated missense mutation Cys634Arg. This finding specifically correlated to the clinic behavior of the corresponding tumor, which was characterized by an unusually aggressive progression with both multiple and recurrent metastases. By examining the possibility that this deletion acts in a manner similar to cysteine substitution, we have analysed the molecular mechanism by which this oncogenic activation occurs. Phosphorylated dimers of the deleted Ret receptor were detected in immunoprecipitates separated under non-reducing conditions. Like other Cys point mutations, this 6 bp deletion affecting two amino acid residues between two adjacent Cys, is capable of activating the transforming ability of Ret by promoting receptor dimerization. These results suggest that alteration to cysteine residue position or pairing is capable of inducing ligand independent dimerization. Furthermore, we present data demonstrating that the processing and sorting of the Ret membrane receptor to the cell surface is affected by mutation type.

Full activation of MEN2B mutant RET by an additional MEN2A mutation or by ligand GDNF stimulation.

Germline mutations of RET gene, encoding a receptor tyrosine kinase, have been associated with the MEN2A and MEN2B inherited cancer syndromes. In MEN2A mutations affecting cysteine residues in the extracellular domain of the receptor cause constitutive activation of the tyrosine kinase by the formation of disulfide-bonded homodimers. In MEN2B a single mutation in the tyrosine kinase domain (Met918Thr) has been identified. This mutation does not lead to dimer formation, but has been shown (both biologically and biochemically) to cause ligand-independent activation of the Ret protein, but to a lesser extent than MEN2A mutations. Intramolecular activation by cis-autophosphorylation of RetMEN2B monomers has been proposed as a model for activation, although alternative mechanisms can be envisaged. Here we show that the activity of RetMEN2B can be increased by stable dimerization of the receptor. Dimerization was achieved experimentally by constructing a double mutant receptor with a MEN2A mutation (Cys634Arg) in addition to the MEN2B mutation, and by chronic exposure of RetMEN2B-expressing cells to the Ret ligand GDNF. In both cases full activation of RetMEN2B, measured by 'in vitro' transfection assays and biochemical parameters, was seen. These results indicate that the MEN2B phenotype could be influenced by the tissue distribution or concentration of Ret ligand(s).

[From the Mailing List SIN: Epidemic of infections caused by 'aquatic' bacteria in patients undergoing hemodialysis via central venous catheters]. / Dalla Mailing-List soci SIN (ML-SIN). Epidemia di infezioni causate da batteri 'acquatici' in pazienti emodializzati tramite cateteri venosi centrali.

UNLABELLED: Bacteremia due to central venous catheter (CVC) infection is the most frequent complication of CVC use as vascular access for hemodialysis (HD). We report a case of an epidemic of CVC infections caused by 3 strains of unusual bacteria: Ralstonia pickettii (Rp), Leifsonia xyli/Leifsonia aquatica (Lxa), Tsuckamurella strandjordae (Ts). From 20/8/01 to 30/9/01, 23 of 35 patients dialyzed via CVCs experienced intra-HD pyrogenic reactions. Their hemocultures were positive for: Rp (14 pts), Lxa (3 pts), Rp+Lxa (5 pts) and Rp+Ts (1 pt). The hemocultures of 12/35 asymptomatic pts were positive for: Rp 2 pts, Lxa 2 pts, Rp+Lxa 2 pts, Ts 1 pt, Rp+Ts 1 pt. The epidemiological and microbiological analyses of environmental samples failed to identify the source of the epidemic. Actions taken were: a) replacement of the batches of disposable materials; b) removal of CVCs in cases where possible to prepare a different access; c) treatment of the infections with intra-CVC antibiotic lock therapy. No relapses were recorded until April 2002, when 8 pts had again pyrogenic reactions due to Rp. After quick substitution of the CVC and repetitions of the action a), no relapses of pyrogenic reactions were observed. CONCLUSIONS: 1) given the characteristics of Rp, Lxa and Ts, saprophytes of moist environments, the most plausible source of the epidemic was a low-charge contaminated solution that was not identified due to low sensitivity of environmental sample culturing methods; 2) antibiotic lock therapy is a viable option for the conservative treatment of CVC infections.

The impact of azathioprine and cyclosporine on long-term function in kidney transplantation.

To assess the impact of cyclosporine on long-term kidney function in transplant patients, we retrospectively analyzed 273 patients on azathioprine and 308 on CsA with graft functioning at 1 year. To balance the length of follow-ups, the observation of patients was cut at 5 years. Actual graft survival rate at 5 years was similar in Aza and CsA (88% vs. 90%). Multivariate analysis in Aza pts showed that proteinuria (P = 0.006) and hypertension at 1 year (P = 0.002) increased the probability of irreversible graft failure by 2.47 and 2.85, respectively. In CsA patients, proteinuria (P = 0.007) and plasma creatinine higher than 2.5 mg/dl (P = 0.006) increased the probability of graft failure by 5.12 and 6.48, respectively. In both Aza and CsA patients with a follow-up of at least 5 years, plasma creatinine levels were significantly worse at 5 years vs. 1 year (P = 0.004). The slopes of plasma creatinine values plotted vs time were not different between the two groups. Chronic graft dysfunction (CGD) was defined as a stable increase of plasma creatinine of at least 50% above stable values at 1 year. The probability of remaining without CGD at 5 years was 75% for CsA and 80% for Aza patients (P = N.S.). Multivariate analysis of factors influencing the development of CGD showed that hypertension (P = 0.003) and proteinuria at 1 year (P = 0.081) increased the probability of developing CGD by 2.19 and 1.76, respectively, in Aza, while in CsA patients proteinuria only (P = 0.063) increased the probability of developing CGD by 2.29. Graft survival at 5 years after development of CGD was 34% in Aza and 53% in CsA-treated patients. These data confirm that in the long-term CsA does not cause a higher prevalence of CGD and show that, in the presence of CGD, CsA has a superior protective effect than Aza.

Central venous catheter-related complications after bone marrow transplantation in children with hematological malignancies.

We studied infectious and mechanical complications occurring with 55 central venous catheters (CVCs) managed in hospital and at home, in 53 children with hematological malignancies who underwent bone marrow transplantation (BMT). The total catheter life span was 6906 days (median 111), 2359 days (median 40) in hospital and 4547 days (median 78.5) at home. Duration of neutropenia was 1241 days (median 20), mostly in hospital. We observed 21 CVC-related infections from 17/55 CVCs (31%): 0.30 episodes/100 days of CVC use with 0.55/100 days in hospital vs 0.17/100 days at home. Antibiotic treatment resolved 72% of infections without CVC removal, which was required in six instances. There were 14 mechanical complications (0.20 episodes/100 days of CVC use) in 6/55 CVCs (11%), with three removals. Interventions to resolve mechanical problems included catheter declotting by urokinase, repair and replacement. We conclude that CVC is an essential component of care of children with cancer undergoing BMT and that it has a relatively low complication rate. Most complications can be resolved by an appropriate CVC handling and by a multidisciplinary intervention in the critical post-BMT phase.

Risk factors for central venous catheter-related infections in surgical and intensive care units. The Central Venous Catheter-Related Infections Study Group.

OBJECTIVE: To identify avoidable risk factors for central venous catheter (CVC) infections in patients undergoing short-term catheterization. DESIGN: Prospective multicenter cohort study. SETTING: Two university teaching hospitals and five large nonteaching hospitals. PATIENTS: Patients admitted to intensive care units or surgical units and exposed to short-term CVCs. RESULTS: Of 623 catheterization episodes, 9.3% were associated with catheter-related infections (CRI). The skin at the catheter site was frequently colonized (16.2%) and was the potential source of infection in 56.1% of the cases, mostly local infections. The hub was colonized less frequently (3.5%) but was responsible for systemic infections more frequently. The following variables were independently associated with CRI: duration of catheterization (for 7 to 14 days, odds ratio [OR], 3.9; 95% confidence interval [CI]95, 1.4 to 10.7; and for > 14 days, OR, 5.1; CI95, 1.7 to 15.4), coronary care unit service (OR, 6.7; CI95, 1.1 to 42.9) or surgery service (OR, 4.4; CI95, 1.03 to 18.5), second episode of catheterization (OR, 7.6; CI95, 1.8 to 32.3), skin colonization at the insertion site (OR, 56.5; CI95, 10.8 to 296), and hub colonization (OR, 17.9; CI95, 2.4 to 132). The risk associated with skin colonization varied with use of jugular access or simultaneous colonization of the hub. When only symptomatic CRI was considered, the risk associated with hub colonization was consistently higher (OR, 36.6; CI95, 7 to 190) than that associated with skin colonization (OR, 3.2; CI95, 0.7 to 14). Age, transparent dressing, jugular insertion, male gender, duration of catheterization, and hub colonization were independent risk factors for skin colonization. The effect of age varied by type of dressing and vice versa; the effect of jugular access varied by sex; and the effect of transparent dressing varied by length of catheterization and vice versa. Total parenteral nutrition and skin colonization were independently associated with an increased risk of hub colonization. CONCLUSIONS: Skin and hub colonization are the two major determinants for endemic CRIs; colonization of the hub, however, is more frequently associated with more severe infections. In order to reduce CRIs, more efforts should be focused on understanding which factors increase the risk of colonization both of the skin and of the hub.

Cardiologic abnormalities in patients with long-term lupus nephritis.

To assess the cardiological status of patients with long-term lupus nephritis we evaluated 30 patients (mean age 43 +/- 11 years) with lupus nephritis lasting from at least 10 years (mean 15 +/- 5 years). At the time of cardiological evaluation the mean plasma creatinine was 132.6 +/- 11.1 mumol/l and in 28 patients lupus had been quiescent for at least 3 years. Fourteen patients (46.6%) showed one or more cardiac abnormalities: 10 had valvular lesions (1 verrucous endocarditis, 9 thickening and stiffness of one or more valves)--4 patients had regional myocardial akinesis as a consequence of a previous cardiac infarct (one had valvular abnormalities too). One patient had pulmonary hypertension probably secondary to pulmonary vasculitis. No patient had pericarditis. These cardiac abnormalities proved to be statistically correlated with the number of ARA criteria (p = 0.045), the number of lupus flares (p = 0.004), the serum levels of cholesterol (p = 0.04) and of triglycerides (p = 0.025) as well as the duration of hypercholesterolemia (p = 0.005) and of hypertriglyceridemia (p = 0.007). In conclusion, in patients with long-term lupus nephritis cardiac lesions are frequent. The main lesions are non-verrucous valvulopathy (probably a consequence of healing verrucous endocarditis) and cardiac infarct (caused by an accelerated atherosclerosis). On the contrary cardiac lesions caused by active lupus as pericarditis, myocarditis and verrucous endocarditis are rare.

Use of simulated blood cultures for antibiotic effect on time to detection of the two blood culture systems BacT/ALERT and BACTEC 9240.

To avoid the influence of pre-analytical steps, this study was performed using sterile blood spiked with defined loads of microorganisms as inoculum. Time-to-Detection (TTD) was evaluated for the most frequently encountered bacteria comparing two commercially available blood culture systems, BD BACTEC 9240 (Becton Dickinson) and BacT/ALERT (Organon Teknika). The effect of the most widely used antibiotics on TTD was evaluated on both systems. TTD was measured with antibiotics at their trough and at increasing concentrations. The results show that the BACTEC PLUS system recovers more pathogens with shorter time to detection than the BacT/ALERT FAN system when beta-lactam antibiotics (Ampicillin, Cefotaxime) are present at their respective trough concentration corresponding to parenteral therapy. The two systems seem to be equally efficient when Gentamicin, Ciprofloxacin and Trimethoprim/sulfamethoxazole are used; in the case of Vancomycin, BACTEC seems more effective than BacT/ALERT.

The gamma nail and the compression-sliding plate in the treatment of pertrochanteric fractures: anesthesiologic aspects.

The authors compare the results obtained in a group of 100 patients submitted to pertrochanteric osteosynthesis during the year 1991 (50 with a gamma nail and 50 with a compression-sliding plate) based on parameters of anesthesiology. The same type of anesthesiology was used in all 100 of the patients, as similar were the general clinical conditions of the patients, ASA classification, and the mean value of preoperative hemoglobin. The gamma nail proved to be preferable in terms of a shorter amount of time required for surgery, a minor loss of blood intra and postoperatively, and minor incidence of complications.

Anesthesiologic findings in surgery for the treatment of trauma of the pelvis.

The authors discuss the numerical increase in fractures of the acetabulum and the extent of surgical indications for their treatment, emphasizing the modernness and the usefulness of methods used to save blood in this type of surgery, which often involves a considerable loss. Out of 150 operations performed between 1985 and 1990 for trauma of the pelvis, 35% of the patients was not transfused with homologous blood, 25% was transfused with 1 U, 40% with several units (4.7 U on the average). Generally, the average quantity of erythrocytes transfused per patient was 2 U (440 ml).

Anesthesia and perioperative treatment in large resections of the pelvic girdle.

The authors examine 24 patients submitted to resection of the pelvic girdle in neoplastic pathology, illustrating the perioperative anesthesiologic procedures used. Sudden variations in blood and plasma volume and increasing hypothermia constitute the main problems. The prevention of hypothermia and continuous invasive monitoring of hemodynamic parameters and of oxygen saturation in mixed venous blood (SvO2) are of primary importance.

Thermodynamic relationships between nateglinide polymorphs.

The physico-chemical characterization of the polymorphs of nateglinide (named B, H and S), an antidiabetic agent, has been performed by means of thermal, diffractometric, spectroscopic and electron microscopic measurements. It has been established that S polymorph can crystallize from the melt obtained from both B and H samples or also following an isothermal treatment of both forms at temperatures lower than the relevant melting points. By X-ray diffraction it could be shown that the three polymorphs have different crystal structure. On the other hand the indication has been drawn from IR spectra that the molecular structure of B is sensibly different from those of H and S forms that have a very similar molecular structure. Finally, the microstructure features of the three polymorphs have been examined by scanning electron microscopy. Our analyses have allowed to evaluate the relative stability of the three polymorphs through the construction of the energy vs. temperature diagram. In particular, S polymorph, the highest-melting form, has resulted to be the only stable form, while the B and H forms are metastable.

A family cluster of Legionella pneumophila infections.

Three members of one single family of 4, the father, a son and a daughter, showed seroconversion against Legionella pneumophila serogroup 1 (Lp SG1). The son had a severe pneumonia, whereas the father and the daughter did not develop any other illness than mild and transient fever. A fourth member, the mother, remained seronegative. Lp SG1 was detected by a direct immunofluorescence test in water samples from the shower at home, in tap water in the family's butcher shop, and in condensation water from the ventilator of refrigerator cells in the shop. Two different sources of infection appear to have occurred: showering at home and an aerosol of contaminated condensation water. Reports of more than one case of legionella infection within a family seem to be extremely rare and have not been found in the literature.