Multidetector-row computerized tomography of aortic injury.
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Aorta↗
Biomedical subjects
Luis A Rivas
Publications and source records attributed to Luis A Rivas.
Penetrating injuries of the neck: use of helical computed tomographic angiography.
The diagnostic evaluation of stable patients with penetrating trauma to the neck remains controversial. Conventional angiography has traditionally been considered the gold standard for evaluation of vascular injuries. The use of angiography for stable patients with penetrating neck trauma has been questioned because of its invasive nature and reported low yield. In recent years, there has been a renewed interest in the use of noninvasive techniques such as helical computed tomographic (CT) angiography for the evaluation of these patients. Helical CT angiography, a low-risk, rapid, accurate, noninvasive, reproducible technique, is less expensive than conventional angiography. Helical CT angiography also can provide information about potential lesions of associated vital structures such as the cervical spine and the aerodigestive tract. This review evaluates the authors' current protocol for penetrating neck wounds and identifies indications for helical CT angiography.
Angiography↗
Changes in race-specific virulence in Pseudomonas syringae pv. phaseolicola are associated with a chimeric transposable element and rare deletion events in a plasmid-borne pathogenicity island.
Virulence for bean and soybean is determined by effector genes in a plasmid-borne pathogenicity island (PAI) in race 7 strain 1449B of Pseudomonas syringae pv. phaseolicola. One of the effector genes, avrPphF, confers either pathogenicity, virulence, or avirulence depending on the plant host and is absent from races 2, 3, 4, 6, and 8 of this pathogen. Analysis of cosmid clones and comparison of DNA sequences showed that the absence of avrPphF from strain 1448A is due to deletion of a continuous 9.5-kb fragment. The remainder of the PAI is well conserved in strains 1448A and 1449B. The left junction of the deleted region consists of a chimeric transposable element generated from the fusion of homologs of IS1492 from Pseudomonas putida and IS1090 from Ralstonia eutropha. The borders of the deletion were conserved in 66 P. syringae pv. phaseolicola strains isolated in different countries and representing the five races lacking avrPphF. However, six strains isolated in Spain had a 10.5-kb deletion that extended 1 kb further from the right junction. The perfect conservation of the 28-nucleotide right repeat of the IS1090 homolog in the two deletion types and in the other 47 insertions of the IS1090 homolog in the 1448A genome strongly suggests that the avrPphF deletions were mediated by the activity of the chimeric mobile element. Our data strongly support a clonal origin for the races of P. syringae pv. phaseolicola lacking avrPphF.
Amino Acid Sequence↗
Inter- and intrarater reliability in computed axial tomographic grading of splenic injury: why so many grading scales?
OBJECTIVE: After splenic trauma, critical decisions regarding operative intervention are often made with the aid of computed axial tomographic (CT) scan findings. No CT scan-based grading scale has been demonstrated to predict accurately which patients require operative or radiologic intervention for their splenic injuries. We hypothesized that use of the most common grading scale, the American Association for the Surgery of Trauma scale, would be associated with low intra- and interreliability scores. We assessed the ability of experienced trauma radiologists to differentiate grade III from grade IV splenic injuries. METHODS: The films of patients who had undergone abdominal CT scanning before splenectomy for grade III or IV injuries were serially evaluated by four trauma radiology faculty weekly for 3 weeks. We assessed intra- and interrater reliability for grading and for presence of contrast blush. RESULTS: Intrarater reproducibility yielded a weighted kappa score of 0.15 to 0.77. Interrater reliability weighted kappa scores ranged from 0 to 0.84, with a mean value of 0.23. CONCLUSION: CT imaging is not reliable for identifying grades III and IV splenic injury, as experienced radiologists often underestimate the magnitude of injury. Interrater reliability is poor. Factors other than the CT grade of splenic injury should determine whether patients require operative or angiographic therapy.
Humans↗
Pseudomonas syringae pv. phaseolicola can be separated into two genetic lineages distinguished by the possession of the phaseolotoxin biosynthetic cluster.
The bean (Phaseolus spp.) plant pathogen Pseudomonas syringae pv. phaseolicola is characterized by the ability to produce phaseolotoxin (Tox(+)). We recently reported that the majority of the Spanish P. syringae pv. phaseolicola population is unable to synthesize this toxin (Tox(-)). These Tox(-) isolates appear to lack the entire DNA region for the biosynthesis of phaseolotoxin (argK-tox gene cluster), as shown by PCR amplification and DNA hybridization using DNA sequences specific for separated genes of this cluster. Tox(+) and Tox(-) isolates also showed genomic divergence that included differences in ERIC-PCR and arbitrarily primed-PCR profiles. Tox(+) isolates showed distinct patterns of IS801 genomic insertions and contained a chromosomal IS801 insertion that was absent from Tox(-) isolates. Using a heteroduplex mobility assay, sequence differences were observed only among the intergenic transcribed spacer of the five rDNA operons of the Tox(-) isolates. The techniques used allowed the unequivocal differentiation of isolates of P. syringae pv. phaseolicola from the closely related soybean (Glycine max) pathogen, P. syringae pv. glycinea. Finally, a pathogenicity island that is essential for the pathogenicity of P. syringae pv. phaseolicola on beans appears to be conserved among Tox(+), but not among Tox(-) isolates, which also lacked the characteristic large plasmid that carries this pathogenicity island. It is proposed that the results presented here justify the separation of the Tox(+) and Tox(-) P. syringae pv. phaseolicola isolates into two distinct genetic lineages, designated Pph1 and Pph2, respectively, that show relevant genomic differences that include the pathogenicity gene complement.
Base Sequence↗
Multislice CT in thoracic trauma.
The introduction of CT imaging in the 1970s revolutionized all aspects of medical care, perhaps nowhere more so than in the evaluation of acutely injured patients. Just as single-slice helical scanning was a great advance over conventional CT, the capabilities of MSCT are proving to be dramatically superior to single-slice methods. Improved contrast bolus imaging, thinner slices, and isotropic voxels should enable the trauma radiologist to identify both major organ system disruption and subtle injuries more promptly. Multiplanar and three-dimensional reconstructions, a forte of MSCT, facilitate rapid communication of disease states with surgeons and others involved in the care of injured patients. In many centers, whole-body CT is beginning to supplant plain films of the chest and spine in the evaluation of severe trauma victims; the cost-effectiveness of such methods is still under evaluation.
Humans↗
Streptomyces lividans contains a minimal functional signal recognition particle that is involved in protein secretion.
The bacterial version of the mammalian signal recognition particle (SRP) is well conserved and essential to all known bacteria. The genes for the Streptomyces lividans SRP components have been cloned and characterized. FtsY resembles the mammalian SRP receptor and the S. lividans SRP consists of Ffh, a homologue of the mammalian SRP54 protein, and scRNA, which is a small size RNA of 82 nt in length. Co-immunoprecipitation studies confirmed that Ffh and scRNA are probably the only components of the S. lividans SRP and that pre-agarase can co-immunoprecipitate with Ffh, suggesting that the SRP is involved in targeting secretory proteins.
Bacterial Proteins↗
Helical abdominal CT scans of 150 patients with CT or surgical diagnoses of small bowel or mesenteric injury.
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Abdomen↗
A comparison of unenhanced helical computerized tomography findings and renal obstruction determined by furosemide 99m technetium mercaptoacetyltriglycine diuretic scintirenography for patients with acute renal colic.
PURPOSE: We assessed unenhanced helical computerized tomography (CT) secondary findings as predictors of renal obstruction as determined by diuretic scintirenography, and determined their reproducibility. MATERIALS AND METHODS: We performed a retrospective review of the records of 77 consecutive patients with unenhanced helical CT findings (stones and secondary findings, including renal parenchymal edema, hydronephrosis, hydroureter, perinephric fat stranding, periureteral fat stranding and extravasation) of urinary lithiasis who had also undergone concomitant diuretic scintirenography during the initial emergency room evaluation during a 1-year period. Unenhanced helical CT films were independently reviewed by 2 attending radiologists (blinded to clinical outcome) to determine interobserver variability. The results were compared to those of diuretic scintirenography. RESULTS: Considerable interobserver variability, as evidenced by kappa values ranging from 0.26 to 0.60, existed for the diagnosis of secondary findings associated with urinary lithiasis on unenhanced helical CT. There was no significant difference in terms of CT findings between patients diagnosed by diuretic scintirenography as having high grade/complete obstruction and those with partial obstruction (p values 0.24 to 0.85 for the 6 unenhanced helical CT findings analyzed). Analyses of variance followed by Tukey's pairwise comparisons showed no significant difference in average number of unenhanced helical CT findings between patients with high grade/complete obstruction (mean plus or minus standard deviation 4.4 +/- 1.31), partial obstruction (4.4 +/- 1.30), and decompression/no obstruction (4.2 +/- 1.16). However, the mean number of unenhanced helical CT findings for patients with normal scintirenography/no obstruction (1.9 +/- 1.41) was significantly different from each of the other 3 diuretic scintirenography groups. Separate logistic regression analyses showed that each unenhanced helical CT finding, except for renal parenchymal edema and urinary extravasation, was a significant predictor of "any degree of obstruction" (high grade and partial obstruction groups) compared to "no obstruction" (decompressed and no obstruction groups). Odds ratios (95% confidence interval) ranged from 6.15 (2.25, 16.82) for perinephric fat stranding to 3.41 (1.30, 8.97) for hydroureter. When these analyses were repeated after exclusion of 8 patients with bladder/passed stones, only perinephric fat stranding and periureteral fat stranding remained significant predictors of "any degree of obstruction," with respective odds ratios of 4.21 (1.49, 11.91) and 4.08 (1.31, 12.65). CONCLUSIONS: Measures of agreement between trained, independent radiologists with respect to unenhanced helical CT secondary findings show considerable variability. The average number of CT consensus findings is not helpful in differentiating patients with variable degrees of obstruction, except for those with normal scintirenography/no obstruction. Unenhanced helical CT findings, except for renal parenchymal edema and urinary extravasation, are significant predictors of "any degree of obstruction" (high grade or partial obstruction) compared to "no obstruction" (decompressed or no obstruction). Therefore, unenhanced helical CT findings may be useful for identifying patients with any degree of obstruction but do not differentiate between those with high grade and partial obstruction.
Acute Disease↗
The Bacillus subtilis 168 csn gene encodes a chitosanase with similar properties to a streptomyces enzyme.
The Bacillus subtilis 168 csn gene encodes a chitosanase. It was found that transcription of the csn gene was temporally regulated and was not subject to metabolic repression. Chitosanase synthesis was abolished in a csn mutant strain. Csn was overproduced in B. subtilis, partially purified and characterized. The deduced amino acid sequence, K(m), and optimal pH and temperature of the B. subtilis enzyme were closer to those of a chitosanase from Streptomyces sp. N174 than to those of chitosanases from other Bacillus strains.
Amino Acid Sequence↗
RT-PCR as a tool for systematic transcriptional analysis of large regions of the Bacillus subtilis genome.
Transcriptional analysis of five different regions of the Bacillus subtilis 168 genome, comprising a total of 175 kb encoding newly identified genes, was carried out using the RT-PCR technique as part of the functional analysis of the whole genome of this bacterium. Amplification of mRNA fragments allowed the detection of both highly and poorly transcribed genes covering 81% of putative ORFs, and also the monitoring of variations in the expression level among genes differentially expressed during particular bacterial growth phases.
Bacillus subtilis↗
Management options of colonoscopic splenic injury.
Injury to the spleen during routine colonoscopy is an extremely rare injury. Diagnosis and management of the injury has evolved with technological advances and experience gained in the management of splenic injuries sustained in trauma. Of the 37 reported cases of colonoscopic splenic injury, 12 had a history of prior surgery or a disease process suggesting the presence of adhesions. Only 6 had noted difficulty during the procedure, and 31 patients experienced pain, shock, or hemoglobin drop as the indication of splenic injury. Since 1989, 21/24 (87.5%) patients have been diagnosed initially using computed tomography or ultrasonography. Overall, only 27.8% have retained their spleens. None have experienced as long a delay as our patient, nor have any had an attempt at percutaneous control of the injury. This report presents an unusual case of a rare complication of colonoscopy and the unsuccessful use of one nonoperative technique, and reviews the experience reported in the world literature, including current day management options.
Aged↗