GSTT1, GSTM1, and GSTP1 polymorphisms as a prognostic factor in women with breast cancer.

The glutathione S-transferase (GST) family comprises phase-II cellular detoxification enzymes that catalyze the conjugation of chemotherapy drugs to glutathione and act on the apoptotic pathway. The aim of this study was to determine whether polymorphisms of the GSTT1, GSTM1, and GSTP1 genes are associated with different rates of overall survival (OS) and disease-free survival (DFS) after neoadjuvant chemotherapy in the management of locally advanced breast cancer, using either simple or combined analyses, and in relation to the post-therapy axillary lymph node status. Forty women with invasive ductal carcinoma of the breast submitted to neoadjuvant chemotherapy with 5-fluorouracil, epirubicin, and cyclophosphamide were genotyped for GSTT1, GSTM1, and GSTP1. Comparisons were performed for the three genes, either isolated or in pairs, in polymorphic or wild-type combinations. Finally, the OS and DFS of patients were analyzed with respect to axillary lymph node status and with respect to wild-type or polymorphic presentations of each gene. No statistically significant difference in OS and DFS was evident between women with wild-type or polymorphic forms of the genes, either isolated or in pairs, after neoadjuvant chemotherapy. By contrast, after treatment, lymph node-negative women had better OS and DFS only in the presence of polymorphisms of GSTP1, and improved DFS only in the presence of the polymorphic types of GSTT1 and GSTM1 compared to women with positive lymph nodes. The presence of polymorphic forms of GSTP1, GSTM1, and GSTT1 was crucial to conferring better OS and DFS among women with negative axillary lymph nodes.

Effect of preheating resin composite and light-curing units on the microleakage of Class II restorations submitted to thermocycling.

This in vitro study evaluated microleakage in Class II cavities restored with dental composite and varying light-curing units and the temperature of the composite when subjected to a thermocycling test. Ninety cavities were prepared on the proximal surfaces of bovine teeth and randomly divided according to the light-curing mode (QTH-420 mW/cm2, LED 2nd generation-1100 mW/cm2, or LED 3rd generation-700 mW/cm2) and temperature of the resin composite (23°C, 54°C and 60°C). Following the restorative procedures and thermocycling, the samples were immersed in methylene blue for 12 hours. The samples were ground and the powder prepared for analysis in an absorbance spectrophotometer. All the results were statistically analyzed using the nonparametric tests of Kruskal-Wallis and Dunn (p ≤ 0.05). The results showed that there was no statistical difference between the light-curing modes at a temperature of 23°C. For 54°C, QTH showed a microleakage mean that was significantly lower than those of the LED groups, and for 60°C, QTH had a microleakage mean significantly lower than that of the LED 2nd generation group. There was no statistical difference between the temperatures of the resin composite when LEDs were used. For QTH, 54°C showed statistically lower microleakage than 23°C. The group preheated to 60°C showed no difference when compared to the group heated to 23°C. Preheating the resin composite (54°C and 60°C) did not improve the microleakage means when high-irradiance LED was used; however, it decreased the microleakage means when a QTH with low irradiance was used.

GSTT1, GSTM1, and GSTP1 polymorphisms and chemotherapy response in locally advanced breast cancer.

The glutathione S-transferase (GST) family consists of phase II detoxification enzymes that catalyze the conjugation of toxic substances, such as chemotherapeutic agents, to glutathione. We examined whether GSTT1/GSTT1"null", GSTM1/GSTM1"null" and GSTP1Ile105Ile/GSTP1Ile105Val polymorphisms are associated with different response rates to neoadjuvant chemotherapy in the treatment of stage II and III breast cancer. Forty Brazilian women with invasive ductal adenocarcinoma of the breast submitted to neoadjuvant chemotherapy, using 5-fluorouracil, epirubicin and cyclophosphamide, were genotyped for the GSTT1, GSTM1 and GSTP1 genes. Clinical response was assessed by RECIST criteria. Comparisons were made for the three genes alone and in pairs, as polymorphic and as wild-type combinations and polymorphic/wild-type combinations. We analyzed all possible combinations and their response rate. Patients with the GSTT1/GSTP1105Ile combination were found to have a significantly better response than GSTT1"null"/GSTP1105Val (P = 0.0209) and GSTT1/GSTM1 (P = 0.0376) combinations. Analysis of all possible combinations showed the GSTM1"null" polymorphic genotype to be present in four, and the wild-type GSTP1105Ile in six of the combinations associated with the largest number of responding patients. We found that patients with the GSTT1/GSTP1105Ile wild-type combination had a significantly higher response rate to chemotherapy than patients with the respective polymorphic GSTT1"null"/GSTP1105Val combination or patients with the wild-type GSTT1/GSTM1. The six gene combinations associated with the largest number of responding patients were found to contain the wild-type GSTP1105Ile and the polymorphic-type GSTM1"null". These specific combinations were virtually absent in the combinations with few responding patients.

Detection of Mycobacterium tuberculosis in corneas from donors with active tuberculosis disease through polymerase chain reaction and culture.

OBJECTIVE: To determine if Mycobacterium tuberculosis can be detected in corneas of donors who have active tuberculosis (TB) disease using polymerase chain reaction (PCR) or culture. DESIGN: This is a prospective cross-sectional study. PARTICIPANTS: 25 corneas (12 from TB-negative donors and 13 from TB-positive donors) from the Sta. Lucia International Eye Bank were submitted to the TB Research Laboratory, Medical Research Laboratory, Department of Medicine, UP-PGH, for diagnostic evaluation. INTERVENTION: Corneas were evaluated using PCR test for M tuberculosis. Acid-fast bacilli smear and culture were also done. MAIN OUTCOME MEASURES: Result of laboratory findings. RESULTS: Among 12 TB-negative donors, there were 2 (16.67%) corneas that were PCR negative for M tuberculosis, whereas 10 (83.33%) corneas were PCR positive for M tuberculosis. Among 13 TB-positive donors, there were 7 (53.85%) corneas that were PCR negative for M tuberculosis, whereas 6 (46.15%) corneas were PCR positive for M tuberculosis. All cultures were negative. CONCLUSION: PCR for M tuberculosis was positive for some TB-positive donors as well as TB-negative donors. However, all cultures were negative. It is recommended that further studies be done to investigate if recipients with PCR-positive corneas will eventually lead to disease transmission or not. It is further recommended that such findings be used to re-evaluate criteria for suitability of donors with tuberculosis.

Correlation of polymorphism C3435T of the MDR-1 gene and the response of primary chemotherapy in women with locally advanced breast cancer.

Primary chemotherapy is a useful strategy for the treatment of locally advanced breast cancer and therefore allows in vivo evaluation of the action of cytotoxic drugs and the possibility of accomplishing conservative breast surgeries, as well as the early treatment of metastasis. Mechanisms of resistance to the drugs include the action of protein associated with the efflux of drugs from the intracellular environment hindering their activity; one of the most studied proteins is P-glycoprotein codified by the MDR-1 gene. The presence of polymorphisms can determine different physiological actions of these proteins, intervening with the response of the drug's action. We evaluated the presence of single nucleotide polymorphism (SNP) C3435T of the MDR-1 gene and its correlation with the response to primary chemotherapy using the RECIST criteria. Forty-one Brazilian women with stages II and III breast cancer using the PCR-RFLP analysis were evaluated. Thirty-three patients with the SNP genotype (TT and CT) and eight patients with the wild genotype (CC) were found; there was no statistically significant correlation between the diverse genotypes and the clinical and pathological responses according to the Cramer correlation coefficient (V = 0.14). The parameters: nuclear and histological degree, and estrogens, progesterone and c-erb B2 receptors did not demonstrate a statistical correlation with the SNP C3435T. Patients with complete pathological response (12.5%) showed only the polymorphic genotype and not the wild genotype. The characteristics of miscegenation in our population could explain the absence of the characterization of a sub-group of individuals where the presence of the polymorphic genotype influenced the response to the primary chemotherapy.

Correlation of polymorphism C3435T of the MDR-1 gene and the response of primary chemotherapy in women with locally advanced breast cancer

Primary chemotherapy is a useful strategy for the treatment of locally advanced breast cancer and therefore allows in vivo evaluation of the action of cytotoxic drugs and the possibility of accomplishing conservative breast surgeries, as well as the early treatment of metastasis. Mechanisms of resistance to the drugs include the action of protein associated with the efflux of drugs from the intracellular environment hindering their activity; one of the most studied proteins is P-glycoprotein codified by the MDR-1 gene. The presence of polymorphisms can determine different physiological actions of these proteins, intervening with the response of the drug’s action. We evaluated the presence of single nucleotide polymorphism (SNP) C3435T of the MDR-1 gene and its correlation with the response to primary chemotherapy using the RECIST criteria. Forty-one Brazilian women with stages II and III breast cancer using the PCR-RFLP analysis were evaluated. Thirty-three patients with the SNP genotype (TT and CT) and eight patients with the wild genotype (CC) were found; there was no statistically significant correlation between the diverse genotypes and the clinical and pathological responses according to the Cramer correlation coefficient (V = 0.14). The parameters: nuclear and histological degree, and estrogens, progesterone and c-erb B2 receptors did not demonstrate a statistical correlation with the SNP C3435T. Patients with complete pathological response (12.5%) showed only the polymorphic genotype and not the wild genotype. The characteristics of miscegenation in our population could explain the absence of the characterization of a sub-group of individuals where the presence of the polymorphic genotype influenced the response to the primary chemotherapy.

Lipid peroxidation-dependent chemiluminescence from the cyclization of alkylperoxyl radicals to dioxetane radical intermediates.

This work reveals a novel mechanism for triplet carbonyl formation (and hence chemiluminescence) during lipid peroxidation, whose chemiluminescence has been attributed to both triplet carbonyls and singlet oxygen. As a model for polyunsaturated fatty acid hydroperoxides, we have synthesized 3-hydroperoxy-2,3-dimethyl-1-butene by photooxygenation of tetramethylethylene. One-electron oxidation of this hydroperoxide with heme proteins and peroxynitrite to the corresponding alkylperoxyl radical results in chemiluminescence, both direct and 9,10-dibromoanthracene-2-sulfonate-sensitized, the latter attributed to the formation of triplet acetone. It is postulated that triplet acetone results from the cyclization of the alkylperoxyl radical to a dioxetane radical intermediate followed by its thermolysis. This is supported by EPR spin-trapping experiments in which discrimination between carbon-centered radicals derived from the alkyloxyl and alkylperoxyl radicals is achieved through the use of one-electron oxidants and reductants, e.g., FeII- and TiIII.

Neutralizing antibodies specific for glycoprotein H of herpes simplex virus permit viral attachment to cells but prevent penetration.

Monoclonal antibodies specific for gH of herpes simplex virus were shown previously to neutralize viral infectivity. Results presented here demonstrate that these antibodies (at least three of them) block viral penetration without inhibiting adsorption of virus to cells. Penetration of herpes simplex virus is by fusion of the virion envelope with the plasma membrane of a susceptible cell. Electron microscopy of thin sections of cells exposed to virus revealed that neutralized virus bound to the cell surface but did not fuse with the plasma membrane. Quantitation of virus adsorption by measuring the binding of purified radiolabeled virus to cells revealed that the anti-gH antibodies had little or no effect on adsorption. Monitoring cell and viral protein synthesis after exposure of cells to infectious and neutralized virus gave results consistent with the electron microscopic finding that the anti-gH antibodies blocked viral penetration. On the basis of the results presented here and other information published elsewhere, it is suggested that gH is one of three glycoproteins essential for penetration of herpes simplex virus into cells.