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.

Plasmid pUM505 encodes a Toxin-Antitoxin system conferring plasmid stability and increased Pseudomonas aeruginosa virulence.

Pseudomonas aeruginosa plasmid pUM505 possesses a pathogenicity island that contains the pumAB genes that encode products with sequence similarity to Toxin-Antitoxin (TA) modules. RT-PCR assays on the overlapping regions of the pumAB genes generated a bicistronic messenger RNA, suggesting that they form an operon. When the pumAB genes were cloned into the pJET vector, recombinant plasmid pJET-pumAB was maintained under nonselective conditions in Escherichia coli cells after six daily subcultures, whereas pJET without pumAB genes was lost. These data indicate that pumAB genes confer post-segregational plasmid stability. In addition, overexpression of the PumA protein in the E. coli BL21 strain resulted in a significant growth inhibition, while BL21 co-expressing the PumA and PumB proteins did not show growth inhibition. These results indicate that pumAB genes encode a TA system where the PumB protein counters the toxic effects of the PumA toxin. Furthermore, P. aeruginosa PAO1 transformants with the pumA gene increased Caenorhabditis elegans and mouse mortality rate and improved mouse organ invasion, effects neutralized by the PumB protein. Moreover, purified recombinant His-PumA protein decreased the viability of C. elegans, indicating that the PumA protein could acts as a toxin. These results indicate that PumA has the potential to promoter the PAO1 virulence against C. elegans and mice when is expressed in absence of PumB. This is the first description, to our knowledge, of a plasmid-encoded TA system that confers plasmid stability and encoded a toxin with the possible ability to increase the P. aeruginosa virulence.

[Testicular carcinoid tumor associated with teratoma: with regard to a case]. / Tumor carcinoide testicular asociado a teratoma: a propósito de un caso.

We report a case of a carcinoid tumor originated in testicle associated with mature teratoma in a 31 years old male. Primary gonadal location of this tumor is unusual, moreover when associated with teratoma. Early diagnosis and treatment determine the prognostic of the patients affected of this neoplasm since the only curative potential treatment is surgery. Follow up must be extent for years due to the possibility of late relapse.

Tumor carcinoide testicular asociado a teratoma: a propósito de un caso / Testicular carcinoid tumor associated with teratoma: with regard to a case

Se presenta un caso de tumor carcinoide de origen testicular asociado a teratoma maduro en un varón de 31 años de edad. La localización gonadal primaria de este tumor es poco usual y más aún, asociado a teratoma. El diagnóstico y tratamiento precoces condicionan el pronóstico de los sujetos afectados por este tipo de neoplasia ya que, el único tratamiento potencialmente curativo es la cirugía. El seguimiento debe prolongarse durante años, debido a la posibilidad de desarrollar metástasis de modo tardío (AU)

We report a case of a carcinoid tumor originated in testicle associated with mature teratoma in a 31 years old male. Primary gonadal location of this tumor is unusual, moreover when associated with teratoma. Early diagnosis and treatment determine the prognostic of the patients affected of this neoplasm since the only curative potential treatment is surgery. Follow up must be extent for years due to the possibility of laterelapse (AU)

[Gastric metastasis from renal cell carcinoma. Pathogenical hypothesis and literature revision]. / Metástasis gástrica de un adenocarcinoma renal. Hipótesis patogénica y revisión de la literatura.

Secondary gastric tumours are very uncommon clinical entities and even more so when the site for the primary tumour is the kidney. Only 11 cases of life diagnosis have been described up to now. Contribution of one case report: a female patient presenting with upper GI tract haemorrhage secondary to gastric metastasis from renal cell carcinoma four years after radical nephrectomy. A literature review is made on the cases described up to date in living patients and a pathogenic hypothesis established based on the theoretical dissemination routes for the cases of gastric location of the metastasis.

Metástasis gástrica de un adenocarcinoma renal. Hipótesis patogénica y revisión de la literatura / Gastric metastasis from renal cell carcinoma. Pathogenical hypothesis and literature revision

Los tumores gástricos secundarios constituyen una entidad clínica poco habitual, más aún si la localización del tumor primitivo es el riñón. Hasta la actualidad tan solo se han descrito 11 casos diagnosticados en vida. Se presenta un caso clínico de una mujer que presentó una hemorragia digestiva alta secundaria a la presencia de una metástasis gástrica de carcinoma de células renales cuatro años después de la nefrectomía radical. Se realiza una revisión bibliográfica de los casos descritos hasta la fecha en pacientes vivos y se establece una hipótesis patogénica de acuerdo a las teóricas rutas de diseminación para los casos de localización metastática gástrica

Secondary gastric tumours are very uncommon clinical entities and even more so when the site for the primary tumour is the kidney. Only 11 cases of life diagnosis have been described up to now. Contribution of one case report: a female patient presenting with upper GI tract haemorrhage secondary to gastric metastasis from renal cell carcinoma four years after radical nephrectomy. A literature review is made on the cases described up to date in living patients and a pathogenichy pothesis established based on the theoretical dissemination routes for the cases of gastric location of the metastasis

Randomised trial of corticosteroids in the treatment of tuberculous pleurisy.

BACKGROUND: Tuberculous pleurisy can result in pleural fibrosis, calcification and thickening. To prevent these complications, corticosteroids are frequently used in addition to antituberculous drugs; however, new therapeutic regimens can control the disease and minimise the sequelae, and there is no convincing evidence of the benefit of the use of corticosteroids as adjuvant therapy. METHODS: Patients received isoniazid 5 mg/kg and rifampicin 10 mg/kg daily for six months. Additionally, they were randomly assigned to a double blind treatment with either prednisone (1 mg/kg/day for 15 days and then tapering off) or placebo during the first month of treatment. Different clinical, radiological, and functional parameters were evaluated to assess the effect of corticosteroids. RESULTS: Fifty seven patients received prednisone and 60 placebo. At the end of the treatment the clinical outcome, the rate of reabsorption of the pleural fluid, the pleural sequelae, as well as lung capacity were similar in both groups. CONCLUSIONS: Corticosteroids do not influence the clinical outcome or the development of long term pleural sequelae in tuberculous pleurisy.

Tuberculous pleural effusion: experience with six months of treatment with isoniazid and rifampicin.

BACKGROUND: Tuberculous pleurisy is associated with small numbers of bacteria. Due to the low rate of primary resistance to antituberculous drugs a two-drug regimen was used to treat the condition. METHODS: Patients received isoniazid 5 mg/kg and rifampicin 10 mg/kg daily for six months. Clinical, radiological, and haematological assessments were performed during treatment and patients were followed up for a median period of 41 (range 6-96) months. RESULTS: One hundred and thirty patients were studied with a mean age of 27 (range 11-53) years. Seven were withdrawn due to parenchymal disease and eight were lost to follow up during the treatment period. Side effects during treatment were frequent (20.7%), but only three patients required a change in medication. No treatment failures were observed. One hundred and fifteen patients completed therapy and were followed up for 41 (range 6-96) months with no evidence of a relapse. CONCLUSIONS: Tuberculous pleurisy responds well to a two-drug regimen of antituberculous therapy given for six months.