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Biomedical subjects

J Rubio

Publications and source records attributed to J Rubio.

At least 37 records · Page 2Linked to original sources
PubMed2001

Genistein potentiates the radiation effect on prostate carcinoma cells.

We have shown previously that genistein, the major isoflavone in soybean, inhibited the growth of human prostate cancer cells in vitro by affecting the cell cycle and inducing apoptosis. To augment the effect of radiation for prostate carcinoma, we have now tested the combination of genistein with photon and neutron radiation on prostate carcinoma cells in vitro. The effects of photon or neutron radiation alone or genistein alone or both combined were evaluated on DNA synthesis, cell growth, and cell ability to form colonies. We found that neutrons were more effective than photons for the killing of prostate carcinoma cells in vitro, resulting in a relative biological effectiveness of 2.6 when compared with photons. Genistein at 15 microM caused a significant inhibition in DNA synthesis, cell growth, and colony formation in the range of 40-60% and potentiated the effect of low doses of 200-300 cGy photon or 100-150 cGy neutron radiation. The effect of the combined treatment was more pronounced than with genistein or radiation alone. Our data indicate that genistein combined with radiation inhibits DNA synthesis, resulting in inhibition of cell division and growth. Genistein can augment the effect of neutrons at doses approximately 2-fold lower than photon doses required to observe the same efficacy. These studies suggest a potential of combining genistein with radiation for the treatment of localized prostate carcinoma.

Antineoplastic Agents↗
PubMed2001

Prospective validation of the association of local tumor stage and grade as a predictive factor for occult lymph node micrometastasis in patients with penile carcinoma and clinically negative inguinal lymph nodes.

PURPOSE: We prospectively validated the association of local tumor stage and grade as a predictive factor for occult lymph node micrometastasis in patients with penile carcinoma and clinically negative lymph nodes. MATERIALS AND METHODS: In a retrospective study of 66 patients we demonstrated the predictive value of the association of local tumor stage and grade for occult micrometastasis, identifying 3 risk groups. A therapy strategy was designed according to these risk groups. A total of 37 consecutive patients were included in a prospective study in which the same criteria for risk group allocation and the same therapeutic recommendations were used as in the retrospective study. RESULTS: In the prospective study we noted positive lymph nodes in 11% of stage T1, 63% of stages T2-3, 15% of grade 1, 67% of grade 2 and 75% of grade 3 cases. The incidence of positive nodes was 0% in the low, 83.3% in the high and 33.3% in the intermediate risk group. These rates were similar to those in the retrospective study with no significant difference. CONCLUSIONS: The predictive value of the association of local tumor stage and grade for occult lymph node micrometastasis was validated in a prospective study. This factor allows the differentiation of 3 risk groups of patients with high reliability in the low and high risk groups. However, other prognostic factors are needed in the intermediate risk group to improve the prediction of lymph node involvement.

Adult↗
PubMed2001

Optimizing dissolved air flotation design and saturation.

Dissolved air flotation (DAF) of iron hydroxide precipitates at working pressures lower than 3 atm, using modified flotation units to improve the collection of fragile coagula, was studied. Conventional DAF flotation was studied as a function of saturation pressure in the absence and presence of surfactants in the saturator. Without surfactants, the minimum saturation pressure required for DAF to occur was found to be 3 atm. But, by lowering the air/water surface tension in the saturator, DAF was possible at a saturation pressure of 2 atm. This behavior was found to occur in both batch and pilot DAF operation tests and almost complete recovery of the precipitates was attained. Results are explained in terms of the minimum "energy" which has to be transferred to the liquid phase to form bubbles by a cavity phenomenon. Further, studies were conducted changing equipment design and feed bubbles size distribution (mixing micro and "mid-sized" bubbles). Thus, bubbles entrance position in the collision-adhesion zone ("capture" zone) was compared to bubble entrance position in the water flow inlet below the floating bed. A "mushroom" type diffuser was used for the "capture zone" experiment and better performance was obtained. Results are explained in terms of different mass transfer phenomena in the collection zone and in the separation zone. Finally, results obtained with the use of a column flotation cell working as normal DAF and with a wide bubble size range are presented. Results indicate good performance and some gains in process kinetics with middle size bubbles.

Air↗
PubMed2000

Molecular evolution and intratumor heterogeneity by topographic compartments in muscle-invasive transitional cell carcinoma of the urinary bladder.

Superficial transitional cell carcinomas (TCC) of the urinary bladder have been shown to be monoclonal. However, no combined study of clonality and tumor suppressor genes (TSG) is available to date for muscle-invasive TCC. Forty-four muscle-invasive TCC of the urinary bladder selected from women were included in this study. Tumor cells located above and below the muscularis mucosa zone were systematically microdissected and used for DNA extraction. Hha-I digested and undigested samples were used to study the methylation pattern of androgen receptor alleles and undigested samples were used for microsatellite analysis of TSG (TP53, RB1, WT1, and NF1). Both loss of heterozygosity (LOH) and single nucleotide polymorphism (SNP) analyses were performed using optimized denaturing gradient gel electrophoresis. The expression of p53, pRB, and p21WAF1 was assessed by immunohistochemistry. Appropriate controls were run in every case. All except two TCC showed a monoclonal pattern with the same allele inactivated in both compartments. Microsatellite analysis of TSG revealed the same LOH/SNP pattern in both tumor compartments in 30 cases (involving more than 1 TSG locus in 8) and genetic heterogeneity in 14 cases. From the latter group, 9 cases expressed more genetic changes in the deep compartment (involving TP53 gene in all cases, WT1 gene in 2, and NF1 in 1), whereas in 4 cases the superficial compartment showed more genetic changes (three involving NF1 and one involving both RB and TP53). No statistical difference in the immunoexpression was detected, although it tended to be higher in the superficial compartment than in the deep compartment. These concordant data in polymorphic DNA regions indicate that bladder-muscle-invasive TCC are monoclonal proliferations with homogeneous tumor cell selection. Heterogeneous tumor cell selection by topography defined two different genetic compartments: superficial, NF1-defective, and deep, TP53-defective. No differences in the immunohistochemical expression were observed, precluding a more extensive clinical application.

Base Sequence↗
PubMed1997

Characterization of the CYP isozyme profile induced by cyclohexanol.

In a previous report we described the ability of cyclohexanol to induce CYP activity. In order to characterize this induction we tested the capacity of liver S9 from rats orally treated with cyclohexanol for 5 days, to activate several carcinogenic nitrosamines into mutagens in the Salmonella typhimurium TA100 test system. Additionally, Western blot analysis of hepatic microsomes from the same treated animals were analysed with specific antibodies against P450 protein families 1A1/A2, 2B1/B2 and 2E1. Cyclohexanol-S9 mixture was more efficient in activating the following nitrosamines: N-nitrosodimethylamine (NDMA), N-nitrosodipropylamine (NDPA), N-nitrosomethylpropylamine (NMPA), N-nitrosodibutylamine (NDBA), and N-nitrosopyrrolidine (NPYR) into bacterial mutagens than S9 from non-treated animals. The mutagenicity of N-nitrosodiethylamine (NDEA) was not modified in the presence of S9 from cyclohexanol-treated animals. Since the main metabolic pathway leading to the production of mutagenic intermediates of NDMA and NPYR is catalysed by isozyme CYP2E1 and that of NDPA, NMPA and NDBA by CYP2B1/B2, mutagenicity experiments predicted that cyclohexanol induces these two P450 isozyme families. Western blot analysis confirmed the results of the mutagenicity assay, showing an increase in the intensity of CYP2E1 and CYP2B1/B2 protein bands in hepatic microsomes from cyclohexanol treated rats in comparison with non-treated controls. Bacterial mutagenicity tests with specific pro-mutagens were good predictors of the P450 induction properties of cyclohexanol.

Animals↗
PubMed1996

Effects of carbon dioxide/bicarbonate on induction of DNA single-strand breaks and formation of 8-nitroguanine, 8-oxoguanine and base-propenal mediated by peroxynitrite.

Carbon dioxide has been reported to react with peroxynitrite (ONOO-), a strong oxidant and nitrating agent, to form an ONO2CO2- adduct, altering the reactivity characteristic of peroxynitrite. We found that bicarbonate (0-10 mM) caused a dose-dependent increase of up to 6-fold in the formation of 8-nitroguanine in calf-thymus DNA incubated with 0.1 mM peroxynitrite, whereas it produced no apparent effect on 8-oxoguanine formation. In contrast, bicarbonate inhibited peroxynitrite-induced strand breakage in plasmid pBR322 DNA and thymine-propenal formation from thymidine. We conclude that C02/HCO3- reacts with peroxynitrite to form a potent nitrating agent, but also to inactivate hydroxyl-radical-like activity of peroxynitrous acid.

Animals↗
PubMed1996

Induction of microsomal enzymes in liver of rats treated with cyclohexanol.

The S9 fraction obtained from rats orally pretreated for 3 days with cyclohexanol was able to activate the pro-mutagen N-nitrosodimethylamine (NDMA) into highly mutagenic metabolite(s) detected in the TA100 strain of Salmonella typhimurium. NDMA was not mutagenic when uninduced S9 was used as metabolic source but was approximately twice more mutagenic with cyclohexanol-induced S9 compared to ethanol-induced S9. Separation of microsomal proteins by sodium dodecylsulfate gel electrophoresis, displayed protein bands situated in the range of 50,000 to 52,000 molecular weight induced by both, ethanol and cyclohexanol. These results are evidence of the induction properties of cyclohexanol.

Animals↗
PubMed1996

Current status of the Plasmodium falciparum genome project.

The Plasmodium falciparum Genome Project is a collaborative effort by many laboratories that will provide detailed molecular information about the parasite, which may be used for developing practical control measures. Initial goals are to prepare an electronically indexed clone bank containing partially sequenced clones representing up to 80% of the parasite's genes and to prepare an ordered set of overlapping clones spanning each of the parasite's 14 chromosomes. Currently, clones of genomic DNA, prepared as yeast artificial chromosomes, are arranged into contigs covering approximately 70% of the genome of parasite clone 3D7, gene sequence tags are available from more than contigs covering approximately 70% of the genome of parasite clone 3D7, gene sequence tags are available from more than 20% of the parasite's genes, and approximately 5% of the parasite's genes are tentatively identified from similarity searches of entries in the international sequence databases. A total of > 0.5 Mb of P. falciparum sequence tag data is available. The gene sequence tags are presently being used to complete YAC contig assembly and localize the cloned genes to positions on the physical map in preparation for sequencing the genome. Routes of access to project information and services are described.

Animals↗
PubMed1996

[Bronchiolitis associated with ulcerative colitis].

Inflammatory bowel disease (IBD) only occasionally affects the lung. Noteworthy among the various pulmonary entities related to IBD are chronic bronchitis and bronchiectasis, though reports of bronchiolitis, obliterants bronchiolitis with organizing pneumonia and other interstitial diseases have also been published. Given the rarity of such pneumopathy, we report a case of bronchiolitis in a patient with a prior diagnosis of ulcerative colitis. We discuss the radiological findings and the results of lung function testing, emphasizin the utility of corticosteroid treatment, which usually leads to a good outcome in pneumopathy secondary to IBD.

Administration, Oral↗
PubMed1996

Isolation and characterization of three serine protease genes in the mosquito Anopheles gambiae.

Three genes encoding serine proteases (Sp6A, Sp6T and Sp8T) were isolated from the malaria mosquito An. gambiae. The proteins that are conceptually translated from these genes contain all amino acids that have been described for this class of proteolytic enzymes, namely the His, Asp and Ser residues at the active site, and the six cysteine residues that form the three disulphide bridges in invertebrate serine proteases. The genes are expressed at low levels and the transcripts were detected only by PCR. Analysis of the nucleotide sequences of the three genes and their pattern of expression indicate that none of the genes code for digestive enzymes, but rather that the proteins have features of the tethered type of serine proteases.

Amino Acid Sequence↗
PubMed1995

Formation of 8-nitroguanine in DNA treated with peroxynitrite in vitro and its rapid removal from DNA by depurination.

Peroxynitrite is a strong oxidant formed by reaction of nitric oxide with superoxide in inflamed tissues. We have demonstrated that 8-nitroguanine is formed dose-dependently in calf thymus DNA incubated with low concentrations of peroxynitrite in vitro. 8-Nitroguanine in acid-hydrolyzed DNA was chemically reduced into 8-aminoguanine, which was analyzed using high performance liquid chromatography with electrochemical detection. Only peroxynitrite, but not nitrite, tetranitromethane nor NO-releasing compounds, formed 8-nitroguanine. Antioxidants and desferrioxamine inhibited the reaction. 8-Nitroguanine was depurinated from DNA incubated at pH 7.4, 37 degrees C (t1/2 = approximately 4 h). Peroxynitrite did not increase 8-oxoguanine levels in DNA.

Animals↗