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J Riera

Publications and source records attributed to J Riera.

At least 37 records · Page 2Linked to original sources
PubMed1996

Prognostic value of DNA image cytometry in colorectal carcinoma.

OBJECTIVE: To investigate the diagnostic sensitivity and prognosis predicting of DNA image cytometry in colorectal carcinoma. STUDY DESIGN: We studied the ploidy status and other DNA cytometric parameters in 68 patients with colorectal carcinoma. In addition, clinical-histologic and follow-up information was collected for at least five years. RESULTS: DNA histograms were available in all cases, showing a diploid DNA distribution pattern in 6 (8.8%), tetraploid in 21 (30.9%), hyperdiploid in 20 (29.4%) and hypertetraploid in 21 (30.9%). The differences in the correlation study between cytometric parameters and pathologic features were not statistically significant. Ploidy status and DNA malignancy grade were individually related to five-year survival (P < .005 and P < .05). CONCLUSION: The data show that DNA image cytometry can provide valuable prognostic information on colorectal carcinomas and may prove useful in guiding adjuvant therapy in these patients.

Adenocarcinoma↗
PubMed1996

Prospective evaluation of different diagnostic techniques for the detection of liver metastases at the time of primary resection of colorectal carcinoma.

OBJECTIVE: To evaluate preoperative and operative methods of detecting liver metastases in patients undergoing primary resection for colorectal carcinoma. DESIGN: Prospective, open study. SETTING: Teaching hospital, Germany. SUBJECTS: 51 Patients with confirmed primary colorectal carcinoma. INTERVENTIONS: Computed tomography during arterial portography (CT-AP), percutaneous ultrasonography (US), operative palpation and examination of the liver, operative US, and computed tomography (CT) follow-up 6-12 months postoperatively. MAIN OUTCOME MEASURES: Sensitivity, specificity, positive and negative predictive value, and accuracy. RESULTS: Overall accuracy was worst for CT during portography, because of the diagnosis of many false positive lesions. Exploration and palpation of the liver had the highest sensitivity (83%) and specificity (100%), and operative US did not give any useful additional information. CONCLUSIONS: Preoperative percutaneous US is recommended as the best non-invasive screening test; otherwise careful inspection and palpation during operation are sufficient for the evaluation of the liver during primary resection for colorectal carcinoma.

Colonic Neoplasms↗
PubMed1995

Cloning, sequence and regulation of expression of the lexA gene of Aeromonas hydrophila.

The lexA gene of Aeromonas hydrophila (Ah) has been isolated by using a specific one-step cloning system. The Ah LexA repressor is able to block Escherichia coli (Ec) SOS gene expression and is likely to be cleaved by the activated RecA protein of this bacterial species after DNA damage. Ah lexA would encode a protein of 207 amino acids (aa), which is 75% identical to the LexA repressor of Ec. Two Ec-like SOS boxes have been located upstream from Ah lexA, the distance between them being 4 bp, whereas this same distance in Ec lexA is 5 bp. The structure and sequence of the DNA-binding domain of the LexA repressor of Ec, as well as the region at which its hydrolysis occurs, are highly conserved in Ah LexA. Moreover, a residue of the region implicated in the specific cleavage reaction, and which is present in all known RecA-cleavable repressors, is changed in the Ah LexA. Expression of Ah lexA is DNA-damage inducible in both the Ah and Ec genetic backgrounds to the same extent. In contrast, Ec lexA is poorly induced in DNA-injured Ah cells.

Aeromonas hydrophila↗
PubMed1995

Frequency source analysis in patients with brain lesions.

In a previous study (Harmony et al. 1993) we observed that the volume of lesions was correlated only with delta power, while the volume and density of edema showed a significant correlation with theta and alpha power, suggesting two independent origins of activity in the delta and theta bands in patients with space-occupying lesions. Our goal in this paper is to show, through a different technique, in a narrow band spectral analysis, that brain lesions are characterized by activity in the delta domain and that edema is better correlated with activity within the theta range. Frequency source analysis based on the Maximum Likelihood (ML) test for rejection of isotropicity was applied to the EEG at rest of 36 patients with space-occupying intracranial lesions. The ML test was rejected at frequencies below 1 Hz and in the low range of the delta rhythm in 31 patients. The origin of the equivalent dipoles at these frequencies was within the volume of the lesion in 27 patients. In 15 patients out of 19 with vasogenic edema the ML test was rejected at frequencies in the theta range. The equivalent dipoles at these frequencies were all within the volume of the edema.

Astrocytoma↗
PubMed1995

A plant metabolic activation system from Persea americana with cytochrome P450-dependent and peroxidase activities.

Microsomal fractions from different tissues of various plants (potato, cauliflower, aubergine, avocado pear, courgette, cucumber, banana, kiwi and strawberry) were prepared and their content of cytochrome P-450 (cyt-P450) determined. A S117 fraction from Persea americana (avocado pear) presented the highest content of cyt-P450. As a consequence of these data, we have developed and characterized this fraction as a plant metabolic activation system. The P. americana S117, used in this work, contains 0.75 +/- 0.04 mg of protein per ml, 0.788 +/- 0.078 nmol of cyt-P450 per mg of protein and has a peroxidase activity of 0.036 +/- 0.005 (nmol tetraguaiacol/micrograms protein/min). The P. americana cyt-P450 remained stable during at least 60 days, stored at -80 degrees C. This fraction activated 2-aminofluorene to a mutagenic product in S. typhimurium TA98, while it had no effect on the benzo[a]pyrene activation. The treatment of the P. americana S117 with CO, the addition of diethyldithiocarbamate (DETC) or the absence of a NADPH-generating system in the activation mix, produced a partial inhibition of the 2-aminofluorene activation. Both peroxidase activity and a cyt-P450-dependent activity are assumed to be involved in the activation of this chemical mediated by P. americana S117.

Benzo(a)pyrene↗
PubMed1994

Interspecies regulation of the recA gene of gram-negative bacteria lacking an E. coli-like SOS operator.

The recA genes of Agrobacterium tumefaciens, Rhizobium meliloti, Rhizobium phaseoli and Rhodobacter sphaeroides, species belonging to the alpha-group bacteria of the Proteobacteria class, have been fused in vitro to the lacZ gene of Escherichia coli. By using a mini-Tn5 transposon derivative, each of these recA-lacZ fusions was introduced into the chromosome of each of the four species, and into that of E. coli. The recA genes of three of the alpha bacteria are induced by DNA damage when inserted in A. tumefaciens, R. phaseoli or R. meliloti chromosomes. The expression of the recA gene of R. sphaeroides is DNA damage-mediated only when present in its own chromosome; none of the genes is induced in E. coli. Likewise, the recA gene of E. coli is not induced in any of the four alpha species. These data indicate that A. tumefaciens, R. meliloti and R. phaseoli possess a LexA-like repressor, which is able to block the expression of their recA genes, as well as that of R. sphaeroides, but not the recA gene of E. coli. The LexA repressor of R. sphaeroides does not repress the recA gene of A. tumefaciens, R. meliloti, R. phaseoli or E. coli.

Agrobacterium tumefaciens↗