Manganese superoxide dismutase content and localization in human thyroid tumours

We describe a procedure for detecting and localizing cytomegalovirus DNA sequences based on in situ hybridization at the ultrastructural level. A digoxigenin-labelled probe, identified with an anti-digoxigenin colloidal gold-labelled antiserum, was employed on infected cells embedded in a new acrylic resin (Bioacryl). The silver enhancement method on the same specimen was used to more easily reveal the reaction also at low magnification. The immunolocalization was characterized by high specificity with virtually no background staining and a good maintenance of submicroscopic cell features.     

Genetic polymorphisms in catechol-O-methyltransferase, menopausal status, and breast cancer risk

Polymorphic catechol-O-methyltransferase (COMT) catalyzes the O-methylation of estrogen catechols. In a case-control study, we evaluated the association of the low-activity allele (COMT(Met)) with breast cancer risk. Compared to women with COMT(Val/Val), COMT(Met/Met) was associated with an increased risk among premenopausal women [odds ratio (OR), 2.1; confidence interval (CI), 1.4-4.3] but was inversely associated with postmenopausal risk (OR, 0.4; CI, 0.2-0.7). The association of risk with at least one low-activity COMT(Met) allele was strongest among the heaviest premenopausal women (OR, 5.7; CI, 1.1-30.1) and among the leanest postmenopausal women (OR, 0.3; CI, 0.1-0.7), suggesting that COMT, mediated by body mass index, may be playing differential roles in human breast carcinogenesis, dependent upon menopausal status.     

Stable expression of manganese superoxide dismutase (MnSOD) in insulinoma cells prevents IL-1beta- induced cytotoxicity and reduces nitric oxide production

The fact that insulin-producing islet beta-cells are susceptible to the cytotoxic effects of inflammatory cytokines represents a potential hinderance to the use of such cells for transplantation therapy of insulin-dependent diabetes mellitus (IDDM). In the current study, we show that IL-1beta induces destruction of INS-1 insulinoma cells, while having no effect on a second insulinoma cell line RIN1046-38 and its engineered derivatives, and that this difference is correlated with a higher level of expression of manganese superoxide dismutase (MnSOD) in the latter cells. Stable overexpression of MnSOD in INS-1 cells provides complete protection against IL-1beta-mediated cytotoxicity, and also results in markedly reduced killing when such cells are exposed to conditioned media from activated human or rat PBMC. Further, overexpression of MnSOD in either RIN- or INS-1-derived lines results in a sharp reduction in IL-1beta-induced nitric oxide (NO) production, a finding that correlates with reduced levels of the inducible form of nitric oxide synthase (iNOS). Treatment of INS-1 cells with L-NMMA, an inhibitor of iNOS, provides the same degree of protection against IL-1beta or supernatants from LPS-activated rat PBMC as MnSOD overexpression, supporting the idea that MnSOD protects INS-1 cells by interfering with the normal IL-1beta-mediated increase in iNOS. Because NO and its derivatives have been implicated as critical mediators of beta-cell destruction in IDDM, we conclude that well regulated insulinoma cell lines engineered for MnSOD overexpression may be an attractive alternative to isolated islets as vehicles for insulin replacement in autoimmune diabetes.     

Effect of natural antioxidants, superoxide dismutase and hydrogen peroxide on capacitation of frozen-thawed bull spermatozoa

This study comprised 100 persons with antibodies to hepatitis C virus (HCV), including 77 intravenous drug users (IVDUs). They were tested with serological HCV typing assays (Murex HCV serotyping 1-6 assay; Chiron RIBA HCV Serotyping SIA). Patients with a positive polymerase chain reaction (PCR) for HCV (n = 66) were tested with genotyping molecular assays (Inno-Lipa HCV II test; Sorin GEN-ETI-K HCV typing assay). Comparison of the results of these tests showed that (a) 92% of samples could be typed by one test at least; 44% could be typed by all four tests; 88% could be typed by one serological test at least and 66% by one molecular test at least; (b) 81% of the samples successfully tested with both serological tests gave comparable results; 95% of the samples successfully tested with both molecular tests gave comparable results; (c) when serological and molecular tests yielded different results, sequences in the 5'-non-coding (5' NC) or E1 regions always confirmed the results of the molecular tests; (d) in case of discrepancy between the results of the molecular tests the E1 region sequences confirmed the Sorin test results. It is concluded that the molecular tests compared gave similar results. The fact that the Murex serological test gave comparable results in more than 80% of cases indicates that it is an alternative to the molecular tests for routine diagnosis. However, comparison of the results of this test with those obtained in patients consulting a hepatology department showed that it gave the best results in a population of patients not exposed repeatedly to HCV.     

Screening for genetic risk of breast cancer

Approximately 10 to 15 percent of all breast cancers are thought to be familial and about one third of these cases are due to an inherited mutation in a BRCA1 or BRCA2 breast cancer-susceptibility gene. The lifetime incidence of breast cancer in mutation carriers is above 50 percent, and carriers of BRCA1 mutation also have a substantially increased risk of ovarian cancer. BRCA1 and 2 mutations are associated with early-onset breast cancer, and some experts call for aggressive screening of affected persons. Monthly self-examination of the breasts beginning at age 18 and annual clinical examinations and mammography after age 25 have been recommended but are of unproven benefit. Prophylactic mastectomy and oophorectomy have been advocated by some authorities, but these interventions are disfiguring and for some carriers of the gene, they are unnecessary. The patient's decision to undergo genetic screening is complicated by the technical difficulty of the test, the substantial cost and the still incomplete understanding of the penetrance of disease in known mutation carriers.     

Evaluating the genetic risk of breast cancer

Progress genetics has endless implication for primary care and for people at risk for hereditary breast cancer. Nurse practitioners will be increasingly challenged to order and interpret genetic tests, provide genetic counseling, and assume responsibility for protecting patient privacy. Yet primary care practitioners may not be completely prepared to provide the necessary background information. This article provides guidelines for evaluating family history risk for inherited breast cancer risk. Also discussed are implications for presymptomatic testing of the BRCA1 and BRCA2 genes for adult-onset breast and ovarian cancer.     

Spectroscopic comparisons of the pH dependencies of Fe-substituted (Mn)superoxide dismutase and Fe-superoxide dismutase

We have compared the active sites of Escherichia coli Fe-substituted (Mn)superoxide dismutase [Fe-sub-(Mn)SOD] and Fe-SOD to elucidate the basis for the inactivity of Fe-sub-(Mn)SOD, despite its apparent similarity to Fe-SOD. The active site of (reduced) Fe2+-sub-(Mn)SOD is qualitatively similar to that of native Fe2+-SOD, indicating similar active site structures and coordination environments for Fe2+. Its nativelike pK is indicative of nativelike local electrostatics, and consistent with Fe2+-sub-(Mn)SOD's retention of ability to reduce O2*- [Vance and Miller (1998) J. Am. Chem. Soc. 120(3), 461-467]. The active site of (oxidized) Fe3+-sub-(Mn)SOD differs from that of Fe3+-SOD with respect to the EPR signals produced at both neutral and high pH, indicating different coordination environments for Fe3+. Although Fe3+-sub-(Mn)SOD binds the small anions N3- and F-, the KD for N3- is tighter than that of Fe3+-SOD, suggesting that the (Mn)SOD protein favors anion binding more than does the (Fe)SOD protein. The EPR spectral consequences of binding F- are reminiscent of those observed upon binding the first F- to Fe3+-SOD, but the EPR spectrum obtained upon binding N3- is different, consistent with crystallographic observation of a different binding mode for N3- in Thermus thermophilus Mn-SOD than Fe-SOD [Lah, M., et al. (1995) Biochemistry 34, 1646-1660]. We find a pK of 8.5 to be associated with dramatic changes in the EPR spectrum. In addition, we confirm the pK between 6 and 7 that has previously been reported based on changes in the optical signal and N3- binding [Yamakura, F., et al. (1995) Eur. J. Biochem. 227, 700-706]. However, this latter pK appears to be associated with much subtler changes in the EPR spectrum. The non-native pKs observed in Fe3+-sub-(Mn)SOD and the differences in the Fe3+ coordination indicated by the EPR spectra are consistent with Fe3+-sub-(Mn)SOD's inability to oxidize O2*- and suggest that its low E degrees is due to perturbation of the oxidized state.     

A meta-analysis of studies of dietary fat and breast cancer risk

One hundred and seventy cancerous lesions observed among 159 esophagectomised specimens were systematically investigated with histochemical staining methods in addition to the ordinary hematoxylin-eosin staining. About 2/3 of them, 113 lesions, were entirely consisted of the squamous elements, regardless with pearl-formation or not, Group 1. On the contrary, the remaining 57 lesions (33.5%) showed foci of esophageal gland-like transformation, Group 2. Those lesions were specified by constituent epithelia with esophageal glandular epithelia-like characteristics; positive for epithelial mucin, secretory component and S-100 protein. Such esophageal gland-like structures could be demonstrated exclusively in cancerous foci penetrated through the lamina muscularis mucosa. Those 113 lesions of the Group 1 did not show any such transformation even by the meticulous examination of the whole lesion by the step sectioning. Those lesions of the Group 2 had a distinct tendency of the perpendicular mural penetration and submucosal extension than the horizontal mucosal involvement, giving rise a characteristic appearance resembling to submucosal tumors. On the contrary, those of the Group 1 showed an ordinary mural extension pattern corresponding to the extent of mucosal involvement, so-to-speak, a typical features of common esophageal cancer. No outstanding difference in biological behaviours could be obviated between two groups so far examined; survival rate, lymph node metastasis, vascular permeation, intraepithelial extension, etc.     

Malonaldehyde, superoxide dismutase and human cataract

UV-spectrophotometry and fluorometry were used to study Malonaldehyde (MDA) and Superoxide Dismutase (SOD) in normal, cataractous human lenses and red blood cells of the patients with cataract. MDA content of senile and complicated cataractous lenses was significantly higher than that of normal human lenses, while that of complicated cataract was significantly higher than that of senile cataract. SOD activity of senile and complicated cataractous lenses was significantly lower than that of normal human lenses, while there was no marked difference between senile and complicated cataractous lenses. Significant correlation between cataractous lenses and red blood cells was not found in MDA content and SOD activity. There was a negative correlation between SOD and MDA in normal human lenses, but no correlation between SOD and MDA in cataractous lenses. The study shows that lipid peroxidation may be one of the possible mechanisms of cataractogenesis in human, and emphasizes the role of SOD in prevention of photoperoxidative damages to the tissues.     

Airway lesions and superoxide dismutase (SOD) distribution in bronchopulmonary dysplasia (BPD)

We examined 71 cases of bronchopulmonary dysplasia (BPD) at autopsy and divided them into five groups on the basis of the patients' survival time, studying on the histological changes in the airways for the purpose of clarifying the pathogenesis of BPD from hyaline membrane disease (HMD). Furthermore, bronchiolar occlusion was classified into four types: secretion, obliterative bronchiolitis, intraluminal plug, and hyperplasia of bronchiolar components. The same occlusive findings as in bronchioli and hyaline membrane were observed from respiratory bronchioles to alveolar ducts. However, there was no obvious correlation between airway lesions and accompanying alveolar lesions excepts three cases of obliterative bronchiolitis. Furthermore, immunohistochemical studies with anti-human SOD antibodies were performed. Mn-SOD was positive for alveolar macrophages in longer surviving infants without significant correlation with histological variation, whereas slightly positive or negative in infants who died within 1 week; CuZn-SOD was rarely positive in any cases. These results is highly correlated to the pathogenesis of BPD and to its pathological advancement with its clinical course.     

Spectral and physical properties of human extracellular superoxide dismutase: a comparison with CuZn superoxide dismutase

A mouse monoclonal IgG1 antibody, referred to as NI-58, has been produced. In immunofluorescence assay, this antibody reacted with myelomonocytes, EBV-B cells, Burkitt's lymphoma cells, T cell leukemia cells and peripheral blood mononuclear cells, but not with erythroid cells. The surface antigen on U937 cells recognized by NI-58 had a molecular size of 65 kDa as determined by immunoblotting analysis. As a biological function, NI-58 strongly inhibited the homotypic cell adhesion of LPS-stimulated U937 cells. It was found that the antigen defined by NI-58 was distinct from CD54 (intercellular adhesion molecule-1) in it's pattern of cellular expression and molecular weight, suggesting that NI-58 recognizes a new adhesion molecule and inhibits the homotypic cell adhesion of LPS-stimulated U937 cells.     

Thiol-dependent metal-catalyzed oxidation of copper, zinc superoxide dismutase

Superoxide dismutase (SOD) is a key enzyme in the antioxidant system of the cells. When exposed to a metal-catalyzed oxidation (MCO) system composed of Fe3+, O2, and thiol as an electron donor copper, zinc SOD (CuZnSOD) was susceptible to oxidative modification and damage as indicated by the loss of activity, fragmentation and aggregation of peptide as well as by the formation of carbonyl groups. Oxidative damage to CuZnSOD was inhibited by diethylenetriaminepentaacetic acid as well as by free radical scavengers and spin-trapping agents. The results of the present study indicate that hydrogen peroxide may be generated from a thiol/Fe3+/O2 system and that hydroxyl free radicals, produced by metal-catalyzed Fenton reactions, may be the ultimate species mediating the SOD damage. Incubation with the MCO system resulted in the release of Cu ions from CuZnSOD. Incubation with the thiol-MCO did not significantly increase the formation of 2-oxohistidine in CuZnSOD. The lack of formation of 2-oxohistidine, as well as the pronounced preventive effect of spin-traps on the thiol-MCO-mediated damage to CuZnSOD, indicates that inactivation might actually be predominantly due to global oxidation rather than a site-specific oxidation. The thiol-MCO-mediated damage to SOD may result in the perturbation of cellular antioxidant defense mechanisms and subsequently lead to a pro-oxidant condition.     

Estrogens, progestogens, normal breast cell proliferation, and breast cancer risk

Epidemiologic studies suggest that ovarian hormones contribute to the development of breast cancer at all stages. Early menopause and premenopausal obesity reduces the risk while postmenopausal obesity and menopausal estrogen replacement therapy increases the risk. Combined oral contraceptives and Depo-Provera do not reduce the risk. It appears that estrogens and progestogens act through and with proto-oncogenes and growth factors to affect breast cell proliferation and breast cancer etiology. Animal studies suggest that estrogen causes interlobular ductal cell division and progesterone causes increased terminal duct lobular unit cell division in the luteal phase. Most breast carcinomas originate from terminal duct lobular unit cells. During pregnancy, these cells fully multiply. Their reproduction is also increased during the luteal phase. Yet, there is considerable interpersonal variation. No studies examining breast cell division have compared cell division rates with serum hormone concentrations, however. The peak of mitosis occurs about 3 days before breast cell death in the late luteal and very early follicular phases. Other research suggests that breast stem cell proliferation is linked to breast cancer development. Endocrine therapy reduces mitotic activity, indicating the estrogen and progesterone receptor content of breast cancers. Hormone-dependent breast cancer cell lines are all estrogen-dependent. Progesterone can block the estrogen-dependent cell lines which act like endometrial cells. The results of the various breast cell proliferation studies in relation to breast cancer are unclear and research identifying a molecular explanation would help in understanding the different findings.     

Methylenetetrahydrofolate reductase polymorphism, dietary interactions, and risk of colorectal cancer

Glomangiosarcoma is a rare malignant variant of the glomus tumor (GT). It has been reported in different anatomical locations, with only 1 report of its localization to the hand, despite the fact that its benign counterpart is most frequently found there. There is only 1 report of glomangiosarcoma that has metastasized. Special attention should be paid to GTs that are not well circumscribed, since the possibility of persistence and malignant transformation is increased in these lesions. The treatment of choice for glomangiosarcomas is wide local excision.     

Effect of high dietary zinc on plasma ceruloplasmin and erythrocyte superoxide dismutase activities in copper-depleted and repleted rats

The effect of moderately high dietary zinc (Zn) on the activities of plasma (PL) ceruloplasmin (CP), and PL and erythrocyte (RBC) copper (Cu), Zn superoxide dismutase (SOD) was determined in weanling rats fed Cu-deficient (DEF; < 1 mg Cu/kg), marginal (MAR; 2 mg Cu/kg), or control (CON; 5 mg Cu/kg) copper diets containing normal or high Zn (HZn; 60 mg/kg) for 4 wk and supplemented with oral Cu (CuS; 5 mg/L) in drinking water for 0, 1, 3, or 7 d. PL Cu decreased (67% compared to CON; p < or = 0.05) in the DEF and increased to control level after 3 d of CuS; increased in the MAR group after 1 d of CuS. HZn reduced overall PL Cu by 27% in all groups, but did not alter the linear increase in PL Cu between 0 and 3 d of Cu S. PL CP activity altered concomitantly with PL Cu levels: The time course of increase in CP activity after 0-3 d of CuS was not influenced by HZn in the diet and CP declined in the DEF group by 92%. There was no correlation between dietary Cu level and PL CP. PL SOD activity decreased by 46% (p < or = .05) in the DEF group, increased to control activity after 1 d of CuS and declined slightly after 7 d; MAR diet did not alter PL SOD. HZn diet increased PL SOD activity in all groups by 150%, reduced activity in the DEF and MAR groups by 65 and 37% and delayed the recovery of PL SOD after CuS. RBC SOD declined in the DEF and MAR groups by 56 and 33% (p < or = 0.05) and did not respond to CuS; HZn diet did not influence RBC SOD activity. These data indicate that moderately high Zn in the diet reduces PL Cu, but not PL CP activity or the recovery of PL Cu or CP activity after oral CuS of Cu-deficient rats, modifies the response of PL SOD to dietary Cu, but does not influence RBC SOD activity.     

Physical activity in usual occupation and risk of breast cancer (United States)

OBJECTIVE: To identify whether the cause, site of ductal obstruction, and characteristics of fluid aspirates are associated with the cryosurvival and fertility after thawing of sperm obtained during reconstruction of the excurrent ducts with microsurgical epididymal sperm aspiration, vasal sperm aspiration, or both. DESIGN: Prospective study. SETTING: Andrology center at a tertiary care institution. PATIENT(S): Men undergoing reconstruction of the excurrent duct and sperm aspiration (n = 42) or microsurgical epididymal sperm aspiration (n = 11). INTERVENTION(S): Sperm were tested for an association with the cause and site of obstruction. Fertilization and pregnancy rates after sperm aspiration and intracytoplasmic sperm injection (ICSI) were evaluated for fresh and frozen aspirates. MAIN OUTCOME MEASURE(S): Motile sperm count and percentage motility after thawing. RESULT(S): The motile sperm count before freezing was significantly higher in the caput epididymis than in the corpus. The motile sperm count before freezing was related inversely to the distance from the caput where the sperm were aspirated. Sperm from clear and opaque fluid aspirates had better percent motility than those from cloudy and creamy fluid aspirates. High fertilization and pregnancy rates were achieved using both fresh and frozen epididymal sperm. CONCLUSION(S): None of the factors studied was associated with cryosurvival of aspirated epididymal or vasal spermatozoa. Because motility is low after thawing, these specimens are best used with ICSI.