Oxidative stress and overexpression of manganese superoxide dismutase in patients with Alzheimer''s disease

Substantial evidence supports the hypothesis that oxygen free radicals are involved in various neurodegenerative disorders. To assess the presence of oxidative stress in Alzheimer's disease (AD) we examined the activity of the enzyme copper-zinc superoxide dismutase (CuZnSOD) in red blood cells, the levels of the mitochondrial inducible enzyme manganese superoxide dismutase (MnSOD) mRNA in lymphocytes, and the total radical-trapping antioxidant capacity (TRAP) in plasma of AD patients and in a group of age-matched non-demented controls. We found that CuZnSOD activity (P<0.01 vs. controls) was significantly increased as well as the MnSOD mRNA levels while the total antioxidant status (P<0.001 vs. controls) was decreased in AD patients. These findings support the role of oxidative alterations in the pathogenetic mechanism underlying AD neurodegeneration.     

Declining asthma prevalence in Hong Kong Chinese schoolchildren

BACKGROUND: Many studies have reported an increase in the prevalence of asthma and related atopic disorders. The lack of standardized methodologies and 'objective' measurements make reliable comparison and monitoring of trends of asthma very difficult. METHODS: In this study, a total of 3321 schoolchildren aged 13-14 years were recruited for study using the Phase III Protocol of the International Study of Asthma and Allergic disease in Childhood (ISAAC). The results were compared with those obtained in the Phase I ISAAC study (1994-95), which used the identical and validated core questionnaires. RESULTS: The prevalence rates of physicians' diagnosis of asthma were similar in the two surveys (11.2% and 10.2%), but the prevalence rates of wheeze (written questionnaire) in the past year have decreased from 12.4% in 1994-95 to 8.7% in 2002 (P<0.001). For the video questionnaire, all asthmatic symptoms in the preceding 12 months were significantly lower in 2002 when compared with those in 1994-95. Among the subjects with diagnosed asthma, the prevalence rates of wheeze in the past 12 months (written questionnaire) has decreased from 39.1% to 27.6% (P<0.001). The prevalence rates of having wheezing attack at least once per month (video questionnaire) has decreased from 10.5% to 5.6% (P=0.013). CONCLUSION: Using the same standardized and validated ISAAC questionnaire, the prevalence rates of asthma symptoms in Hong Kong Chinese schoolchildren have decreased since 1994. The exact reasons for such trend remain to be explored.     

Different mechanisms for the induction of copper-zinc superoxide dismutase and manganese superoxide dismutase by progesterone in human endometrial stromal cells

BACKGROUND: The present study was undertaken to investigate the cAMP-dependent regulation of copper-zinc superoxide dismutase (Cu,Zn-SOD) and manganese SOD (Mn-SOD) by ovarian steroids in human endometrial stromal cells (ESC). METHODS and RESULTS: To examine the effect of cAMP on SOD expression, ESC were incubated with dibutyryl-cAMP (db-cAMP, 0.5 mmol/l), forskolin (25 micromol/l), or estradiol (E(2), 10(-8) mol/l) + medroxyprogesterone acetate (MPA, 10(-6) mol/l), for 18 days. E(2) + MPA significantly increased Cu,Zn-SOD activity and mRNA concentrations, whereas db-cAMP and forskolin had no effect. On the other hand, Mn-SOD activity and mRNA concentration were significantly increased by all of these treatments. Insulin-like growth factor-binding protein-1, a marker of decidualization, was clearly induced by db-cAMP, forskolin or E(2) + MPA, accompanied by morphological changes characteristic of decidualization. To study whether the increase in Mn-SOD by db-cAMP or E(2) + MPA was mediated by cAMP-dependent protein kinase A (PKA), ESC were incubated with protein kinase inhibitor (PKI) (10 microg/ml), an inhibitor of PKA, in the presence of db-cAMP or E(2) + MPA. The increase in Mn-SOD activity following db-cAMP or E(2) + MPA was completely inhibited by PKI. CONCLUSIONS: In the process of decidualization, E(2) + MPA increases Mn-SOD expression via a cAMP-dependent pathway. Cu,Zn-SOD is also up-regulated by E(2) + MPA, but via a different pathway from that involving cAMP.     

锰超氧化物歧化酶基因Ala(-9)Val多态性与2型糖尿病视网膜病变的相关性

目的 探讨锰超氧化物歧化酶(manganese superoxide dismutase,Mn-SOD)基因Ala(-9)Val多态性与2型糖尿病视网膜病变发生的关联性.方法 应用PCR-直接测序方法检测了中国湖北地区汉族264例2型糖尿病患者和198名正常对照者的Mn-SOD基因Ala(-9)Val多态性(GCT→GTT).结果 (1)2型糖尿病组与正常对照组比较,VV基因型频率(72.7%vs 67.2%,P>0.05)与V等位基因频率(76.1%vs71.0%,P>0.05)差异无统计学意义.(2)在2型糖尿病者中,有糖尿病视网膜病变(diabetic retinopathy,DR)组 VV基因型频率为79.2%,与无糖尿病视网膜病变(non-diabetic retinopathy,NDR)组(66.9%)比较,差异有统计学意义(x2=5.015,P=0.025);V等位基因频率在DR组为82.4%,NDR组为70.5%,差异亦有统计学意义(x2=10.253,P=0.001);NDR组与正常对照组比较,VV基因型频率(66.9%vs67.2%,P>0.05)及V等位基因频率(70.5%vs 71.0%,P>0.05)差异无统计学意义,V等位基因与2型糖尿病视网膜病发生相关(OR=1.96,95%CI:1.29-2.97).(3)基因型为VV型的2型糖尿病患者其Nn-SOD水平较AA型、AV型患者低,差异有统计学意义(P=0.025),其总超氧化物歧化酶有增加趋势,但差异无统计学意义(P>0.05).结论 Mn-SOD基因Ala(-9)Val多态性与2型糖尿病发病无关,但可能参与了2型糖尿病视网膜病变的发生、发展过程.     

A pilot study of the association of manganese superoxide dismutase and glutathione peroxidase 1 single gene polymorphisms with prostate cancer and serum prostate specific antigen levels

Introduction

The aim of the study was to evaluate the potential association of single gene polymorphisms of the antioxidant enzymes manganese superoxide dismutase (MnSOD) and glutathione peroxidase (GPX1) with prostate cancer (PCa).

Material and methods

Manganese superoxide dismutase and glutathione peroxidase 1 genotypes and allele frequencies in 49 prostate cancer cases (PCa group) and 98 control subjects were determined. Analysis of genotypes in control group individuals were performed in two subgroups according to serum prostate-specific antigen levels: the control group (n = 49), with prostate specific antigen (PSA) level < 4 ng/ml; and the nonPCa-high PSA control group (n = 49), with serum PSA > 4 ng/ml. Determination of MnSOD Ala-9Val and GPX1 Pro198Leu polymorphisms was performed using real-time polymerase chain reaction amplification.

Results

No association was found between GPX1 polymorphisms and PCa in all groups (p > 0.05). In the PCa group, the frequency of homozygote Val allele carriers was significantly higher in comparison to nonPCa-high PSA control cases. Therefore, Val/Val genotype was found significantly suspicious for PCa risk (OR = 2.48; 95% CI: 1.37–4.48; p = 0.002). Furthermore, an overall protective effect of the Ala allele of the MnSOD polymorphism on PCa risk was detected. These findings in this small Turkish population suggested that individual risk of PCa may be modulated by MnSOD polymorphism especially in patients with high PSA, but GPX1 polymorphism seemed to have no effect on PCa risk.

Conclusions

The presence of genetic variants of antioxidant enzymes could have a potential influence on genesis of prostatic malignancy.     

Polymorphism of extracellular superoxide dismutase (EC-SOD) gene: relation to the mutation responsible for high EC-SOD level in serum

Summary Extracellular superoxide dismutase (EC-SOD) with amino acid substitution R213G generated by the nucleotide substitution 760C→G in the heparin binding domain is responsible for the high EC-SOD level in serum. We identified the two DNA polymorphic sites in the coding region of EC-SOD gene related to the 760C→G and determined the allele frequencies. The polymorphisms were A and G at nucleotide position (nt.) 241 and C and T at nt. 280 near the N-terminal. The haplotype frequencies in Japanese were 241A280C: 0.45, 241G280T: 0.37, and 241G280C: 0.18. The haplotype of 241A280T did not exist. The mutation 760C→G must occur on the allele having the haplotype of 241G280T.     

IL-4和IL-4受体基因多态性与成人变应性哮喘的关系

目的　研究白细胞介素 4 (IL 4 )、IL 4受体α链的 2个基因多态性位点与中国成人变应性哮喘的关系。方法　采用病例对照方法 ,用聚合酶链反应 限制性片段长度多态性方法 (PCR RFLP)对IL 4启动子区C - 5 89T和IL 4Rα链Q5 76R进行基因分型。结果　IL 4C - 5 89T与中国成人变应性哮喘无关 ,然而 ,变应性哮喘组IL 4Rα链 5 76R R频率显著性高于对照组 (χ2 =9.36 9,P <0 .0 1;OR =3.797) ,且与血浆高IgE相关。结论　IL 4Rα链 5 76R R基因型是中国成人变应性哮喘的基因危险因子     

Protective role of superoxide dismutase in human sperm motility: superoxide dismutase activity and lipid peroxide in human seminal plasma and spermatozoa.

The levels of superoxide dismutase (SOD), a highly specific scavenging enzyme for superoxide anion radicals (O2-), and lipid peroxide produced by oxygen free radicals were measured in human seminal plasma and spermatozoa. Seminal plasma contained 366.8 +/- 20.9 U/ml (mean +/- SE) of SOD activity. SOD activity in human spermatozoa showed a significant correlation to the number of motile spermatozoa, while the activity in seminal plasma did not relate to the sperm concentration or motility. The lipid peroxide concentration in seminal plasma was 6.22 +/- 0.46 nmol/ml and had no significant relationship to sperm concentration or motility. The malondialdehyde (MDA) concentration in spermatozoa was significantly related to the number of immotile spermatozoa. A decrease in the motility of spermatozoa incubated in medium without seminal plasma was observed after 120 min, while the MDA concentration of the spermatozoa increased. Addition of exogenous SOD (400 U/ml) to the sperm suspension significantly decreased this loss of motility and the increase of the MDA concentration. These data suggest a significant role for SOD in sperm motility. It seems that lipid peroxidation of human spermatozoa may cause loss of motility and that SOD may inhibit this lipid peroxidation. These results suggest that SOD may have a possible clinical application in the use of spermatozoa for in-vitro fertilization (IVF) or artificial insemination.     

Evaluation of the efficacy of a hospital-based asthma education programme in patients of low socioeconomic status in Hong Kong

BACKGROUND: Good asthma control requires optimal medical treatment in conjunction with appropriate self-management. In the West, the effectiveness of patient education on improving self-management has been well documented. However, data amongst Asian populations are lacking. We performed a pilot study to evaluate the efficacy of a hospital based education programme aimed at improving self-management skills and reducing morbidity in a Chinese population with low socioeconomic status and education level. METHODS: Our asthma education programme was a low-cost programme conducted in essence by specialist respiratory nurses. Patients attending our asthma clinic were instructed during a two-hour educational session on the pathophysiology of asthma, its potential triggers, the appropriate use of medications including proper inhaler techniques, and the self-management of their disease. These instructions were reinforced by video sessions at subsequent outpatient clinic attendance when patients' inhaler and peak flow techniques were checked by the same nurses and their self-management plan re-examined by the attending physicians. Asthma knowledge, inhaler technique, FEV1 and peak expiratory flow (PEF), and patients' self-rating of their asthma were determined at baseline, 6 months and 1 year after the intervention. Morbidity was assessed by the numbers of hospitalizations, unscheduled visits to family physicians and accident and emergency department attendance, courses of oral steroid used and days off work or school at baseline and 1 year. RESULTS: Two hundred and thirty patients were recruited for the study, 83% completing the entire assessment period. The group demonstrated significant improvements in lung function: the mean FEV1 +/- SD increased from 63.6 +/- 20.6% of predicted values at baseline to 68.5 +/- 22.3% at 6 months and 68.6 +/- 22.8% at 1 year (P < 0.05), and the mean PEF +/- SD increased from 64.6 +/- 23.0% of predicted values at baseline to 75.4 +/- 27.0% at 6 months and 76.8 +/- 24.5% at 1 year(P < 0.001). There were also significant improvements in inhaler technique (P < 0.01), asthma knowledge (P < 0.001), patients' self-rating of their asthma (P < 0.05), and reductions in the numbers of hospitalizations (P < 0.01), visits to family physicians (P < 0.001) and accident and emergency department attendance (P < 0.001) during the study period. Patients with moderate to severe asthma as defined by an FEV1 of < 80% of predicted values were most likely to benefit from the programme. CONCLUSIONS: We conclude that patient education is likely to be an essential component in the holistic approach to the management of asthma even amongst Asian populations of low socioeconomic status and education level. Further studies using randomised controlled trials are necessary to consolidate our findings.     

The suppressive effect of gelatin-conjugated superoxide dismutase on disease development and severity of collagen-induced arthritis in mice.

We studied the effect of superoxide dismutase (SOD) on murine collagen-induced arthritis (CIA), an animal model of human rheumatoid arthritis (RA). Among SOD derivatives studied, only gelatin-SOD conjugate which has prolonged half life in vivo was effective to suppress the development of CIA, while native SOD or gelatin carrier alone was ineffective. Interestingly, pyran polymer-conjugated SOD which also has a long half life showed no suppressive effect on the disease. No significant effect on immune response against type II collagen (CII) was found in any of the experimental groups. In addition, induction of suppressor cells was not detected in spleen or lymph node cells of the gelatin-SOD-treated group. Therefore, these results suggest that oxygen radicals may have an important role in the effector phase of the immune response to manifest this chronic autoimmune polyarthritis. Thus, the use of appropriate antioxidants for the treatment of human RA may be rationalized.     

溃疡性结肠炎患者血清超氧化物歧化酶及脂质过氧化物的变化

用黄嘌呤氧化法及硫代巴比妥酸反应产物比色法分别对120例溃疡性结肠炎患者血清超氧化物歧化酶（SOD）及脂质过氧化物（LPO）含量进行检测。结果表明：溃疡性结肠炎患者SOD明显低于对照组（P＜0．001）;LPO明显高于对照组（P＜0．001）。其中单纯湿热内蕴型或兼胃虚弱型或兼脾虚气滞血瘀型或兼阴虚气滞血瘀型血清SOD含量均明显低于对照组（P＜0．001）;而血清LPO含量均明显高于对照组（P＜0．001）。结果提示：以湿热内蕴型为主的溃疡性结肠炎患者清除氧自由基,保护细胞免受损伤的SOD降低,而间接反映细胞损伤的LPO升高。当伴有虚证时,尤以脾胃虚弱型或脾虚气滞血瘀型的溃疡性结肠炎患者SOD含量明显降低和LPO含量明显增高。     

Relationship between glutathione S-transferase gene polymorphisms and enzyme activity in Hong Kong Chinese asthmatics

BACKGROUND: Asthma is a disease associated with oxidative stress. The glutathione S-transferases (GST) are a group of enzymes that protect cells from oxidative stress. Functional genetic polymorphisms of GST genes (GSTT1, GSTM1 and GSTP1) have previously been reported. OBJECTIVE: To investigate the association of GST gene polymorphisms and its enzyme activity with the risk of asthma in Hong Kong Chinese adults. METHODS: An age- and smoking status-matched case-control study was carried out on 315 patients with asthma and 315 healthy controls. Genotyping was carried out on genomic DNA using the PCR and/or restriction fragment length polymorphism (PCR-RFLP). Plasma GST activity was measured by fluorometric assay. RESULTS: The distribution of various genotypes or alleles of the GSTT1, GSTM1 and GSTP1 was not significantly different between patients with asthma and healthy controls. The GSTM1 null genotype was found to be protective from the development of asthma in atopic subjects (odds ratios 0.55, 95% confidence interval 0.34-0.90; P=0.017). However, there was no association between GSTT1 and GSTM1 null genotypes and enzyme activity. GSTP1 codon 105 Val variants led to reduced plasma GST activity in healthy controls. Asthma patients had elevated plasma GST activity compared with healthy controls irrespective of their genotypes (P<0.001). CONCLUSION: Our data suggest that among atopic subjects, the GSTM1 null genotype is associated with a decreased risk for asthma despite increased level of plasma GST activity in asthma, but it could not distinguish whether this increase is a potentially protective compensatory effect or a pathogenic factor.     

The levels of superoxide dismutase,catalase, and carbonic anhydrase in erythrocytes of patients with Down's syndrome

Summary The levels of cytoplasmic superoxide dismutase (SOD₁), catalase (CAT'ase), and carbonic anhydrase isoenzymes (CA-B and CA-C) were determined in the erythrocytes from 11 male patients with Down's syndrome. The levels of SOD₁ and CAT'ase, as well as CA-B showed significant increases compared with those in normal controls, whereas the CA-C level did not change substantially. In addition, a positive correlation was noted between the levels of SOD₁ and of CAT'ase (r=0.764).Supported in part by a grant from the Japanese Ministry of Education     

Biochemical and electron paramagnetic resonance study of the iron superoxide dismutase from Plasmodium falciparum

Recombinant iron-containing superoxide dismutase (Fe-SOD) from Plasmodium falciparum was produced in a SOD-deficient strain of Escherichia coli, purified and characterised. The enzyme is a dimer, which contains 1.7 Fe equivalents and is sensitive to hydrogen peroxide (H(2)O(2)). Electron paramagnetic resonance (EPR) analysis showed two different signals, reflecting the presence of two different types of high-spin Fe sites with different symmetries. The role of the W71 residue during inactivation by H(2)O(2) of the P. falciparum Fe-SOD was studied by site-directed mutagenesis. First, the W71V mutation led to a change in the relative proportion of the two Fe-based EPR signals. Second, the mutant protein was almost as active as the wild-type (WT) protein but more sensitive to heat inactivation. Third, resistance to H(2)O(2) was only slightly increased indicating that W71 was marginally responsible for the sensitivity of Fe-SOD to H(2)O(2). A molecular model of the subunit was designed to assist in interpretation of the results. The fact that the parasite SOD does not belong to classes of SOD present in humans may provide a novel approach for the design of antimalarial drugs.     

Immunohistochemical study on tissue transglutaminase and copper-zinc superoxide dismutase in human myocardium: Its relevance to apoptosis detected by the nick end labelling method

The influence of free radicals on apoptosis was studied in the human heart; 45 autopsy cases were examined by the nick end labelling method (NELM) that detects DNA fragmentation. Immunostaining for copper-zinc superoxide dismutase (CuZn-SOD) and tissue transglutaminase (tTG) induced frequently during apoptosis were also studied. Positive immunoreaction for tTG was detected in mucinous degeneration of myocardial cells; these same cells were also positive for CuZn-SOD but negative for NELM. Myocardial cells showing basophilic alterations after haematoxylin and eosin staining were also positive for CuZn-SOD but negative for the other markers examined. Positive nuclear reaction by NELM was only observed in myocardial cells showing contraction band necrosis or irregularly shaped nuclei surrounding recent or long-standing infarcted foci. In these the other two markers were negative. Since mucinous degeneration lacks the distinguishing morphological features of apoptosis, immunoreactive tTG in this lesion may not imply that the cells are undergoing apoptosis. tTG can be induced in non-apoptotic conditions and may not be involved in apoptosis induced by infarction. Histological disassociation between CuZn-SOD expression and apoptosis suggests the possibility of a cytoprotective role played by endogenous CuZn-SOD against free radical generation in the human heart.