Role of PumB antitoxin as a transcriptional regulator of the PumAB type-II toxin-antitoxin system and its endoribonuclease activity on the PumA (toxin) transcript.

The PumAB type-II toxin-antitoxin (TA) system is encoded by pumAB genes that are organized into an operon. This system is encoded by the pUM505 plasmid, isolated from a Pseudomonas aeruginosa clinical strain. The pumA gene encodes a putative RelE toxin protein (toxic component), whereas the pumB gene encodes a putative HTH antitoxin protein. The expression of the PumAB system in Escherichia coli confers plasmid stability. In addition, PumA toxin overexpression in P. aeruginosa possesses the capability to increase bacterial virulence, an effect that is neutralized by the PumB antitoxin. The aim of this study was to establish the mechanism of regulation of the PumAB toxin-antitoxin system from pUM505. By an in silico analysis of the putative regulatory elements, we identified two putative internal promoters, PpumB and PpumB-AlgU (in addition to the already reported PpumAB), located upstream of pumB. By RT-qPCR assays, we determined that the pumAB genes are transcribed differentially, in that the mRNA of pumB is more abundant than the pumA transcript. We also observed that pumB could be expressed individually and that its mRNA levels decreased under oxidative stress, during individual expression as well as co-expression of pumAB. However, under stressful conditions, the pumA mRNA levels were not affected. This suggests the negative regulation of pumB by stressful conditions. The PumB purified protein was found to bind to a DNA region located between the PpumAB and the pumA coding region, and PumA participates in PumB binding, suggesting that a PumA-PumB complex co-regulates the transcription of the pumAB operon. Interestingly, the pumA mRNA levels decreased after incubation in vitro with PumB protein. This effect was repressed by ribonuclease inhibitors, suggesting that PumB could function as an RNAse toward the mRNA of the toxin. Taken together, we conclude that the PumAB TA system possesses multiple mechanisms to regulate its expression, as well as that the PumB antitoxin generates a decrease in the mRNA toxin levels, suggesting an RNase function. Our analysis provides new insights into the understanding of the control of TA systems from mobile plasmid-encoded genes from a human pathogen.

Perceived insecurity, mental health and urbanization: Results from a multicentric study.

AIMS: This article aims to (1) explore the levels of perceived insecurity in a sample of patients with mood or anxiety disorders and (2) assess whether living in 'big cities' can influence the levels of patients' perceived insecurity and social contacts compared to living in a non-urbanized context. METHODS: A total of 24 Italian mental health centers (MHCs) have been invited to participate. Twenty patients consecutively accessing the MHC have been recruited. All patients have been assessed using validated assessment tools. RESULTS: The sample consisted of 426 patients, mostly female, with a mean age of 45 years. Globally, 52.2% of patients had a diagnosis of mood disorders, and 37.8% had anxiety disorders. Half of the sample declared that the main feeling toward life is uncertainty; higher levels of pessimistic views toward life have been detected in patients living in urban areas. A positive association between negative attitudes toward life and higher levels of depressive and anxiety symptoms, poor social functioning and higher levels of perceived psychological distress has been found. CONCLUSION: Our findings confirm the presence of a common sense of perceived uncertainty among our sample. Such attitude toward life can have a detrimental impact on patients' psychological and physical well-being, contributing to high levels of distress.

The use of first generation versus second generation antipsychotics as add-on or as switch treatment and its effect on QTC interval: the Italian experience in a real-world setting.

Some psychotropic drugs are connected with prolongation of the QT interval, torsade de pointes and sudden death. Recent data suggest that with regard to this adverse effect, the atypical antipsychotic drugs are no safer than the older drugs. The purpose of this study is to evaluate the different use of first generation versus second generation antipsychotics as add-on (Group I) or switch treatment (Group II) and its effect on QTc interval in a sample of schizophrenic and bipolar inpatients without medical illness. All patients had been evaluated twice by using ECG: on admission and after two weeks of hospitalization. Exclusions criteria were: abnormalities in levels of potassium, magnesium and calcium, cardiovascular and metabolic diseases, alcohol or drug abuse. We found a significant (p < 0.01) greater use of first generation antipsychotic in Group I (73.80%) than in the Group II (33.33%). Also Group I showed a significant increase (p < 0.0001) in total chlorpromazine equivalent (476. 78 ± 448.80 mg/day vs 845.48 ± 491.64 mg/day) and in QTc interval (369.14 ± 33.75 ms vs 387.09 ± 31.97 ms), while we did not find any statistical difference in Group II during hospitalization. Our results, in spite of the small sample size, indicate that antipsychotic add-on can increase QTc interval more than switching to other antipsychotic in psychiatric patients without other risk factors.

Thymidylate synthase structure, function and implication in drug discovery.

Recent methodologies applied to the drug discovery process, such as genomics and proteomics, have greatly implemented our basic understanding of drug action and are giving more input to medicinal chemists, in finding genuinely new targets and opportunities for the development of drugs with original mechanisms of action. In this paper, an example of the successful application of some new techniques to the target enzymes with the Thymidylate Synthase (TS) function is given. The improved knowledge of the complex mechanism of the biological pathways in which thymidylate synthase is involved represents a unique chance to find new mechanism-based inhibitors, aimed to treat not only cancerous diseases, but also infectious pathologies. Thymidylate synthase (TS or ThyA) has long been considered as one of the best-known drug targets in the anti-cancer area, after which old and new drugs, such as 5-fluoro uracil and the anti-folate ZD1694, have been introduced into chemotherapy to treat solid tumours. Only a few attempts have been made to find non-classical anti-folate inhibitors that are dissimilar to the folate co-factor, with the aim of finding unshared protein target domains on the enzyme structure, in order to specifically inhibit TS enzymes from pathogens. Only recently from omic studies, a new Thymidylate Synthase Complementing Protein (TSCP or ThyX) has been identified in a number of pathogens, showing a different structure with respect to human TS, thus opening new avenues to specific inhibitions. A depiction of the most recent progress in the study of Thymidylate Synthase enzymes is presented in the following sections.

Aggressive fibromatosis of the larynx: report of a new case in an adult patient and review of the literature.

We describe a case of aggressive fibromatosis of the larynx occurring in a 75-year-old man. The lesion manifested with voice hoarseness and swallowing difficulty. A computerized tomographic scan of the neck revealed distortion of the glottic profile. A malignant tumor was suspected. Although a laryngoscopy-driven biopsy was non-diagnostic, total laryngectomy was done, since the lesion was not deemed amenable to conservative therapy. Grossly, the glottic rim was infiltrated by a hard, grey-white tissue showing a tentacular outline. Tissue sections featured a moderately cellular lesion composed of spindle cells with bland, tapered nuclei, enmeshed in a variably collagenized ground substance. Delicate spindle cell fascicles surrounded the native submucosal seromucous glands and had invaded the thyroid cartilage and the thyroid gland as well. The spindle cells were immunopositive for actins and vimentin, and negative for keratins, epithelial membrane antigen, desmin, and S-100 protein. No further therapy was administered. Periodic follow-up visits were negative. The patient died 5 years after surgery of myocardial infarction with no clinical evidence of lesion recurrence. Based on the available literature, our data confirm that laryngeal fibromatosis in adult patients is a locally infiltrating and progressive disease. Total laryngectomy with clear margins is needed as to avoid the high risk of local recurrence.

[Ultrasonically guided biopsy of the prostate for the diagnosis of carcinoma]. / La biopsia ecoguidata della prostata per la diagnosi di carcinoma.

Echoguided biopsy of the prostate is a new method used in the diagnosis of carcinoma. False negatives, which range between 7% and 27% of transperineal biopsies, can be reduced to 11% using ultrasound control. In 50% of cases carcinoma are located in the hypoechogenic area, in 45% in mixed echogenic areas and in 5% in hyperechogenic areas. The diagnosis of carcinoma was performed in 40.7% of patients examined. In conclusion, this method is shown to be a valuable and advisable aid.