[Diagnostic correlation between magnetic resonance imaging and arthroscopic findings in anterior cruciate ligament injuries]. / Correlación diagnóstica entre resonancia magnética y hallazgos artroscópicos en lesiones de ligamento cruzado anterior.

PURPOSE OF THE STUDY: determine the sensitivity and specificity of magnetic resonance imaging in anterior cruciate ligament injuries and associated injuries through arthroscopic findings. MATERIAL AND METHODS: this is a retrospective, longitudinal, cross-sectional study in 96 patients with ACL injuries were included and who underwent arthroscopic surgery; arthroscopic findings were compared with diagnostic magnetic resonance images as well as associated lesions. RESULTS: for ACL lesions the following data were found in relation to the agreement by MRI and arthroscopic findings; 93.68% sensitivity, 100% specificity. Negative predictor value of 14.28% and a positive predictor value of 100%. CONCLUSION: MRI is an accurate and non-invasive imaging modality for the evaluation of knee injuries, the diagnostic association is considerably high.

PROPÓSITO DEL ESTUDIO: determinar la sensibilidad y especificidad de la resonancia magnética en lesiones de ligamento cruzado anterior, así como las lesiones asociadas mediante los hallazgos artroscópicos. MATERIAL Y MÉTODOS: se trata de un estudio retrospectivo, longitudinal, transversal en el cual se incluyeron 96 pacientes con lesiones de ligamento cruzado anterior (LCA) que fueron sometidos a cirugía artroscópica; los hallazgos artroscópicos se compararon con las imágenes diagnósticas de resonancia magnética así como lesiones asociadas. RESULTADOS: en lesiones de LCA se encontraron los siguientes datos en relación a la concordancia por resonancia magnética nuclear (RMN) y hallazgos artroscópicos; sensibilidad de 93.68%, especificidad de 100%. Valor predictor negativo de 14.28% y un valor predictor positivo de 100%. CONCLUSIÓN: la RMN es una modalidad de imagen precisa y no invasiva para la evaluación de lesiones de la rodilla, la asociación diagnóstica con el examen clínico es considerablemente alta.

The Salmonella enterica Serovar Typhi ltrR Gene Encodes Two Proteins Whose Transcriptional Expression Is Upregulated by Alkaline pH and Repressed at Their Promoters and Coding Regions by H-NS and Lrp.

LtrR is a LysR-type regulator involved in the positive expression of ompR to promote ompC and ompF expression. This regulatory network is fundamental for the control of bacterial transformation and resistance to the bile salt sodium deoxycholate in Salmonella enterica serovar Typhi. In this work, the transcriptional regulation of ltrR was characterized, revealing that the use of alternative promoters results in two transcripts. The larger one, the ltrR2 mRNA, was repressed at promoter and coding regions by H-NS, whereas Lrp repressed its expression at the coding region. In the case of the second and shorter ltrR1 transcript, it was repressed only at the coding region by H-NS and Lrp. Remarkably, pH 7.5 is a positive signal involved in the transcriptional expression of both ltrR units. Translational fusions and Western blot experiments demonstrated that ltrR2 and ltrR1 mRNAs encode the LtrR2 and LtrR1 proteins. This study adds new data on the complex genetic and regulatory characteristics of one of the most predominant types of transcriptional factors in bacteria, the LysR-type transcriptional regulators.IMPORTANCE The LysR-type transcriptional regulators are present in viruses, archaea, bacteria, and eukaryotic cells. Furthermore, these proteins are the most abundant transcriptional factors in bacteria. Here, we demonstrate that two LysR-type proteins are generated from the ltrR gene. These proteins are genetically induced by pH and repressed at the promoter and coding regions by the global regulators H-NS and Lrp. Thus, novel basic aspects of the complex genetic regulation of the LysR-type transcriptional regulators are described.

The Salmonella enterica serovar Typhi ltrR-ompR-ompC-ompF genes are involved in resistance to the bile salt sodium deoxycholate and in bacterial transformation.

A characterization of the LtrR regulator, an S. Typhi protein belonging to the LysR family is presented. Proteomics, outer membrane protein profiles and transcriptional analyses demonstrated that LtrR is required for the synthesis of OmpR, OmpC and OmpF. DNA-protein interaction analysis showed that LtrR binds to the regulatory region of ompR and then OmpR interacts with the ompC and ompF promoters inducing porin synthesis. LtrR-dependent and independent ompR promoters were identified, and both promoters are involved in the synthesis of OmpR for OmpC and OmpF production. To define the functional role of the ltrR-ompR-ompC-ompF genetic network, mutants in each gene were obtained. We found that ltrR, ompR, ompC and ompF were involved in the control of bacterial transformation, while the two regulators and ompC are necessary for the optimal growth of S. Typhi in the presence of one of the major bile salts found in the gut, sodium deoxycholate. The data presented establish the pivotal role of LtrR in the regulatory network of porin synthesis and reveal new genetic strategies of survival and cellular adaptation to the environment used by Salmonella.

cAMP receptor protein (CRP) positively regulates the yihU-yshA operon in Salmonella enterica serovar Typhi.

Salmonella enterica serovar Typhi (S. Typhi) is the aetiological agent of typhoid fever in humans. This bacterium is also able to persist in its host, causing a chronic disease by colonizing the spleen, liver and gallbladder, in the last of which the pathogen forms biofilms in order to survive the bile. Several genetic components, including the yihU-yshA genes, have been suggested to be involved in the survival of Salmonella in the gallbladder. In this work we describe how the yihU-yshA gene cluster forms a transcriptional unit regulated positively by the cAMP receptor global regulator CRP (cAMP receptor protein). The results obtained show that two CRP-binding sites on the regulatory region of the yihU-yshA operon are required to promote transcriptional activation. In this work we also demonstrate that the yihU-yshA transcriptional unit is carbon catabolite-repressed in Salmonella, indicating that it forms part of the CRP regulon in enteric bacteria.

SoxS regulates the expression of the Salmonella enterica serovar Typhimurium ompW gene.

OmpW of Salmonella enterica serovar Typhimurium has been described as a minor porin involved in osmoregulation, and is also affected by environmental conditions. Biochemical and genetic evidence from our laboratory indicates that OmpW is involved in efflux of and resistance towards paraquat (PQ), and its expression has been shown to be activated in response to oxidative stress. In this study we have explored ompW expression in response to PQ. Primer extension and transcriptional fusions showed that its expression was induced in the presence of PQ. In silico analyses suggested a putative binding site for the SoxS transcriptional factor at the ompW regulatory region. Electrophoretic mobility shift assays (EMSAs) and footprinting experiments showed that SoxS binds at a region that starts close to -54 and ends at about -197 upstream of the transcription start site. Transcriptional fusions support the relevance of this region in ompW activation. The SoxS site is in the forward orientation and its location suggests that the ompW gene has a class I SoxS-dependent promoter.

[Neonatal hearing loss screening: our results three years after starting the program]. / Despistaje de la hipoacusia neonatal: resultados después de 3 años de iniciar nuestro programa.

Since the 90s there increasing interest in early detection of neonatal hearing loss due to the feasibility of universal neonatal screening as well as to the possibility of early intervention. This has led to set up neonatal screening programs based upon otoacoustic emissions and to a great increase in the number of publications in the field. Our hospital started a neonatal hearing loss screening program using otoacoustic emission in March 2000. We used a Capella Cochlear Emissions (MADSEN electronics) equipment. Until May 2003 we have performed the test in 6372 children with a median age of 71 days. In our study, the sensibility of the test was 90.9% and the specificity 99.7%. Our results are similar to those reported in the literature although the age of the children was higher and we have found an incidence of hearing loss lower than other studies.

Positive end-expiratory pressure increases intraocular pressure in cats.

BACKGROUND AND METHODS: The purpose of the present study was to examine the effect of various levels of positive end-expiratory pressure on intraocular pressure in cats. Fourteen healthy adult cats (2.6 to 3.7 kg) without evidence of ocular disease were anesthetized with pentobarbital, paralyzed, and placed on mechanical ventilation. Direct continuous measurements of heart rate (HR), mean arterial pressure (MAP), CVP, CSF pressure, and intraocular pressure were recorded at zero end-expiratory pressure, and at 5, 10, and 15 cm H2O positive end-expiratory pressure, applied in random order. MAIN RESULTS: There were no significant changes in pHa, Paco2, HR, MAP, hematocrit, and temperature. Intraocular pressure increased significantly from 17 (during zero end-expiratory pressure) to 20 mm Hg at 10 cm H2O positive end-expiratory pressure; at 15 cm H2O positive end-expiratory pressure, intraocular pressure increased significantly to 21 mm Hg. CVP and CSF pressure increased significantly in parallel with intraocular pressure at 5, 10, and 15 cm H2O positive end-expiratory pressure. CONCLUSIONS: We speculate that similar responses occur in man, and may be undesirable in patients with already increased intraocular pressure, when higher levels of positive end-expiratory pressure are used.