体外厌氧条件下载铜蒙脱石杀菌效果的研究

载铜蒙脱石的杀菌作用通过脑心浸液肉汤 (BHI)二倍系列稀释法来判定其最小抑菌浓度 (MIC)。释放入肉汤和生理盐水中Cu2 的量通过原子吸收光谱仪测定。杀菌动力学研究采用改良的振荡瓶法。结果表明 :厌氧条件下 ,载铜蒙脱石具有很强的杀菌性能。载铜蒙脱石对放线共生放线杆菌的最小抑菌浓度为 2 .5 6mg/ml;对血液链球菌为 5 .12mg/ml。测得肉汤二倍稀释的载铜蒙脱石释放出的Cu2 量在 2 .39～ 38.6 5 ppm之间 ,在生理盐水中释放的Cu2 量为 1.85～ 15 .82ppm。本试验结果表明 ,蒙脱石无抗菌性能。     

饮食性缺铜、缺锌对小鼠细胞因子产生的影响

３周龄小鼠饲用６周缺铜饮食后，出现胸腺萎缩、肝脏肿大以及明显的缺铜指征，包括血清Ｃｐ活性、肝Ｃｕ含量、ＣＣＯ和Ｃｕ，Ｚｎ－ＳＯＤ活性明显下降。缺钢小鼠产生的ＴＮＦ－α、ＩＬ－１和ＩＬ－６水平明显低于正常组小鼠。小鼠饲予７周缺锌饮食后，出现明显脱毛，虽然肝Ｚｎ含量降低不明显，但ＴＮＦ－α、ＩＬ－１和ＩＬ－６活性明显降低，说明上述细胞因子是小鼠缺锌的敏感指征之一。本文结果显示正常Ｃｕ、Ｚｎ水平对ＴＮＦ－α、ＩＬ－１和ＩＬ－６产生的重要性，并提示这些细胞因子的改变可能是缺铜、缺锌引起的免疫功能损害的细胞、分子学机理之一。     

妊娠期血清微量元素的变化

目的探讨妊娠期血清微量元素的变化规律。方法以原子吸收分光光度法分别测定421例孕妇和128例正常对照妇女血清铜(Cu)、锌(Zn)、铁(Fe)等微量元素浓度和血清镁(Mg)、钙(Ca)浓度。结果血清铜(Cu)在整个孕期内无显著性变化,P>0.05;血清锌(Zn)、铁(Fe)、镁(Mg)、钙(Ca)随孕期的增加而降低,P均<0.05。结论孕妇在妊娠期内应根据不同孕期,合理补充微量元素。     

Preventing HIV-1 Tat-induced neuronal apoptosis using antioxidant enzymes: mechanistic and therapeutic implications

HIV-1 proteins, especially gp120 and Tat, elicit reactive oxygen species (ROS) and cause neuron apoptosis. We used antioxidant enzymes, Cu/Zn superoxide dismutase (SOD1) and glutathione peroxidase (GPx1) to study signaling and neuroprotection from Tat-induced apoptosis. SOD1 converts superoxide to peroxide; GPx1 converts peroxide to water. Primary human neurons were transduced with SV40-derived vectors carrying SOD1 and GPx1, then HIV-1 Tat protein was added. Both SV(SOD1) and SV(GPx1) delivered substantial transgene expression. Tat decreased endogenous cellular, but not transduced, SOD1 and GPx1. Tat rapidly increased neuron [Ca(2+)](i), which effect was not altered by SV(SOD1) or SV(GPx1). However, both vectors together blocked Tat-induced [Ca(2+)](i) fluxes. Similarly, neither SV(SOD1) nor SV(GPx1) protected neurons from Tat-induced apoptosis, but both vectors together did. Tat therefore activates multiple signaling pathways, in one of which superoxide acts as an intermediate while the other utilizes peroxide. Gene delivery to protect neurons from Tat must therefore target both.     

A dopamine receptor antagonist L-745,870 suppresses microglia activation in spinal cord and mitigates the progression in ALS model mice

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by a selective loss of motor neurons in the motor cortex, brainstem, and spinal cord. It has been shown that oxidative stress plays a pivotal role in the progression of this motor neuron loss. We have previously reported that L-745,870, a dopamine D4 receptor antagonist, selectively inhibits oxidative stress-induced cell death in vitro and exerts a potent neuroprotective effect against ischemia-induced neural cell damage in gerbil. To investigate the efficacy of L-745,870 in the treatment of ALS, we here conducted a chronic administration of L-745,870 to transgenic mice expressing a mutated form of human superoxide dismutase gene (SOD1^H46R); a mouse model of familial ALS, and assessed whether the mice benefit from this treatment. The pre-onset administration of L-745,870 significantly delayed the onset of motor deficits, slowed the disease progression, and extended a life span in transgenic mice. These animals showed a delayed loss of anterior horn cells in the spinal cord concomitant with a reduced level of microglial activation at a late symptomatic stage. Further, the post-onset administration of L-745,870 to the SOD1^H46R transgenic mice remarkably slowed the disease progression and extended their life spans. Taken together, our findings in a rodent model of ALS may have implication that L-745,870 is a possible novel therapeutic means to the treatment of ALS.     

Immunohistochemical study of the kidneys after severe muscular injury

Severe muscular injury sometimes causes renal failure, and myoglobin in skeletal muscle is known to induce toxic free oxygen radicals in the kidneys. The relationship between the immunohistochemical expression of myoglobin and the scavenger copper/zinc superoxide dismutase (Cu/Zn-SOD) was investigated in kidneys taken from two autopsy groups, a group with tourniquet shock (n = 4), and a group with severely injured skeletal muscle (n = 18). Paraffin-embedded kidney sections were used for immunohistochemical staining by the avidin-biotin-complex (ABC) method using antibodies against myoglobin and Cu/Zn-SOD. Detection of the two antigens was analyzed qualitatively. In most cases of tourniquet shock in which the survival time was considered to be relatively long, myoglobin staining was positive and Cu/Zn-SOD was negative. Among the seven cases of severely injured skeletal muscle in which the survival period was considered to be relatively short, positive staining was detected immunohistochemically for both myoglobin and Cu/Zn-SOD. Moreover, in most of the cases in this group that showed acute tubular necrosis, immunohistochemical staining was negative for both markers, whereas positive staining was found for most of the cases in which the kidneys were revealed to be normal by HE staining. These findings suggest that when myoglobin enters the kidneys via the circulation, Cu/Zn-SOD reacts to eliminate free radicals, but is depleted by consumption in the long run, and that there might be a relationship between these histological findings and immunohistochemical expression. Received: 2 December 1999 / Accepted: 22 May 2000     

Evaluation of striatal oxidative stress in patients with Parkinson's disease using [62Cu]ATSM PET

Introduction

To clarify the role of oxidative stress and mitochondrial dysfunction in the pathogenesis of Parkinson's disease (PD) in living patients, positron emission tomography (PET) with [⁶²Cu]diacetyl-bis(N⁴-methylthiosemicarbazone) ([⁶²Cu]ATSM) was applied to functional imaging of oxidative stress mainly due to mitochondrial dysfunction in the striata of patients with PD.

Methods

Fifteen PD patients who presented with lateral dominant symptoms at onset and six healthy controls underwent [⁶²Cu]ATSM PET. Dynamic PET data acquisition was performed, and standardized uptake values (SUVs) were obtained from the delayed phase of dynamic data by means of region of interest analysis. The striatum-to-cerebellum SUV ratio (S/C ratio) was calculated from the SUV in all subjects of the striatum and the cerebellar cortex.

Results

The mean S/C ratio of the bilateral striata of the patients (1.15±0.10) was significantly increased compared with that of the controls (1.08±0.02) (P<.05). In the patients, the S/C ratio of the bilateral striata showed a positive correlation with the Unified Parkinson's Disease Rating Scale (UPDRS) rating (r=0.52, P<.05), and the S/C ratio of the striatum contralateral to the initially affected body side showed a strong positive correlation with the UPDRS rating (r=0.62, P<.05).

Conclusions

[⁶²Cu]ATSM PET imaging demonstrated that striatal oxidative stress was enhanced in PD patients compared with the controls and increased with the progression of disease severity, particularly in the contralateral striatum. These findings indicated that oxidative stress associates with striatal neurodegeneration in PD.     

Attenuation effects of heparin–superoxide dismutase conjugate on bleomycin-induced lung fibrosis in vivo and radiation-induced inflammatory cytokine expression in vitro

In this study, the effects of heparin–superoxide dismutase conjugate (heparin–SOD) on bleomycin-induced pulmonary fibrosis in vivo and on inflammatory cytokine expression in vitro were evaluated. To investigate the effects of heparin–SOD on pulmonary fibrosis, heparin–SOD was administered to bleomycin (BLM)-treated mice by intraperitoneal injection once a day and the hydroxyproline content in lung was determined per 7 days. The degree of fibrosis was assessed quantitatively using histopathologic features. The results showed that heparin–SOD inhibited BLM-induced lung fibrotic lesions as reflected by the decrease of lung hydroxyproline content and lung fibrosis grade 28 days after BLM instillation. The in vitro effects on the cytokine level expressed by irradiated 3T3 fibroblasts showed that heparin–SOD significantly lowered the levels of transforming growth factor-β1 and interleukin-1β. These results strongly demonstrated that heparin–SOD might be useful in the prevention and treatment of pulmonary fibrosis.