Superoxide dismutase activity of normal murine liver, regenerating liver, and H6 hepatoma.

By means of both direct assay and gel electrophoresis, normal A/J mouse liver was shown to possess both Cu-Zn and Mn superoxide dismutase (SD) activity. H6 hepatoma cells contained Cu-Zn SD activity, but no Mn SD activity was detectable. Isolated mitochondria from normal liver contained both forms of the enzyme, but isolated mitochondria from H6 hepatoma cells contained no SD activity. To ascertain whether this loss of Mn SD activity was characteristic of these tumor cells or was simply a property of rapidly dividing cells, SD activity was measured in regenerating liver. Mn SD activity was present in the regenerating liver at all times after surgery. Hence loss of the Mn SD activity seemed to be a characteristic of some tumor cells but not of corresponding rapidly dividing normal cells.     

中频交变磁场照射后小鼠的行为学变化

目的:目前电磁辐射对生物体行为学方面的研究还很薄弱,设立不同磁场的强度和不同照射的周期,观察中频领域磁场照射对小鼠的自主活动和学习记忆的影响。方法:实验于2007-05-10/06-15在清华大学医学院和中国医学科学院药用植物研究所完成。①实验材料:磁场发生装置:中频交变磁场发生装置由清华大学工程物理系医学物理与工程研究所自主研发,可产生频率为40kHz,场强为28.8A/m,28.8kA/m的中频交变磁场。自主活动测试箱:中国医学科学院药用植物研究所提供,为一可封闭的金属箱,内置摄像头。4只黑色塑料测试桶分别置于箱子四角。水迷宫测试箱:中国医学科学院药用植物研究所提供。②实验动物及方法:将80只小鼠随机分为不同场强照射组和对照组。强磁场照射1组:11.6kA/m/40kHz,1h/d,连续照射7d。强磁场照射2组:11.6kA/m/40kHz,2h/d,连续照射7d。强磁场照射3组:11.6kA/m/40kHz,2h/d连续照射15d。弱磁场照射组:28.8kA/m/40kHz,2h/d,连续照射7d。对照组除了未放入磁场照射,其他条件与照射组一致。实验过程中对动物处置符合动物伦理学要求。③实验评估:观察其一般活动的改变,并采用自主活动测试箱和水迷宫测试箱进行测试,观察各组小鼠的自主活动和学习记忆的改变。结果:①一般行为观察:与对照组小鼠对比,经过中频交变磁场照射过的各组小鼠活跃度减低,毛色较差。强磁场照射3组(145G,2h/d,连续15d)于第11天和13天分别死亡1只。②自主活动检测结果:强磁场照射2,3组小鼠的运动路程、运动速度、运动时间明显低于对照组(P<0.05)。③水迷宫测试结果:在学习记忆检测阶段撤掉平台,发现各组动物2min内穿越平台原来所在象限的次数没有明显差别(P>0.05)。结论:中频交变磁场照射会给小鼠的自发活动造成一定影响,对学习记忆没有影响。     

Evaluation of the role of reactive oxygen species in doxorubicin hydrochloride nephrosis

In subcellular systems, doxorubicin hydrochloride (ADR) leads to the generation of reactive oxygen species such as superoxide anion. Because reactive oxygen species have been shown to be important mediators of glomerular injury in several animal models, we sought to determine whether reactive oxygen species play a significant role in the pathogenesis of ADR-induced nephrotic syndrome in the rat. Rats pretreated with a variety of free radical scavengers (superoxide dismutase conjugated to polyethylene glycol [PEGSOD], catalase, catalase plus PEGSOD, dimethylsulfoxide, desferoxamine, or n-acetyl cysteine) had no significant reduction in proteinuria at 3 weeks after ADR administration when compared with rats receiving ADR in the absence of scavengers. No evidence was seen of increased lipid peroxidation or depletion of reduced glutathione in renal cortex tissue obtained up to 24 hours after administration of ADR. No changes were seen in the renal cortical levels of either enzyme activity or immunoreactive protein for the endogenous antioxidant enzymes superoxide dismutase (either the Mn or CuZn forms) or catalase after ADR. Total and MnSOD activities in glomeruli isolated from rats after ADR administration fell significantly, though CuZnSOD activity was increased. The effect of ADR on cultured rat mesangial or epithelial cells was also evaluated. ADR inhibited growth of both cell types at concentrations of approximately 5 to 10 mumol/L, an order of magnitude below the reported Michaelis-Menten constant for ADR-induced superoxide production. The growth inhibitory effect could not be prevented in either cell type by treatment with PEGSOD, catalase, or PEGSOD plus catalase. This combination of results from in vivo and in vitro studies provides no evidence for an important role of reactive oxygen species in ADR nephrosis and suggests that other known mechanisms of ADR cytotoxicity, such as interference with DNA metabolism, mediate the glomerular injury.     

Titanium elastic nailing in femoral diaphyseal fractures of children in 6-16 years of age

Background:

Management of femoral diaphyseal fractures in the age group of 6-16 years is controversial. There has been a resurgence worldwide for operative fixation.

Materials and Methods:

Twenty-two children (18 boys, 4 girls) aged 6-16 years with recent (> 3 days) femoral diaphyseal fractures (20 closed, 2 open) were stabilized with Titanium Elastic Nail (TEN). These fractures were in proximal third (n=3), middle third (n=15) and in the distal third (n=4) 17 patients underwent surgery within seven days of their injury. The results were evaluated using Flynn''s scoring criteria. Statistical analysis was done using Fischer''s exact test.

Results:

All 22 patients were available for evaluation after a mean of 26 months (14-36 months) of followup. Radiological union in all cases were achieved in a mean time of 8.7 weeks. Full weight bearing was possible in a mean time of 8.8 weeks. Mean duration of hospital stay was 9.8 days. The results were excellent in 13 patients (59.0%), successful in six (27.2%) and poor in three patients (13.6%). All patients had early return to school.

Conclusion:

Intramedullary fixation titanium elastic nailing is an effective treatment of diaphyseal fractures of the femur in properly selected patients of the 6-16 years age group.     

Anterior compartment pressure measurement in closed fractures of leg

Background:

Compartment syndrome is a potentially devastating condition. Increased intracompartmental pressure has been incriminated as the primary pathogenic factor in compartment syndrome. The purpose of this prospective study was to monitor the anterior compartmental pressure and differential pressure to minimize the incidence of acute compartment syndrome.

Materials and Methods:

Seventy-five consecutive cases of closed fractures of leg presenting within six hours of injury were taken for measurement of anterior compartment pressure at the level of fracture and at 5 cm and 10 cm away from the fracture site, using the Whitesides'' infusion technique. A differential pressure of less than 30 mm Hg was taken as the criterion for diagnosis of compartment syndrome.

Results:

Two patients (2.67%) developed acute compartment syndrome. The mean anterior compartment pressures were highest at the level of the fracture and went on decreasing as we went away from the fracture site, which was found to be statistically significant (P < 0.001).

Conclusion:

Compartment pressure measurement is the most reliable and objective method for early diagnosis of compartment syndrome. Whitesides'' infusion technique is a relatively easy and inexpensive method to come to a diagnosis of compartment syndrome in a developing country like India. Differential pressure is more reliable than absolute pressure in predicting the development of an impending compartment syndrome.     

A case study in planning for public health education: the organ and tissue donation experience.

The chasm between the supply and demand of donated organs and tissues continues to grow despite widespread public awareness of transplantation and numerous efforts to educate the public about organ donation. It is fast becoming a significant public health problem in this country. The need for more effective public education is well documented in the literature on transplantation and is a primary objective of organizations in the transplant field. In response to this need, the Division of Organ Transplantation in the Health Resources and Services Administration of the Public Health Service initiated a project to examine the nature and scope of donation education initiatives throughout the country, to identify shortcomings, and to suggest ways the Federal Government could contribute to the effectiveness of public education in organ and tissue donation. The project resulted in the development of a protocol that also is applicable to other health education programs. Its major steps consisted of assessing the status of donation-related public education in the United States, identifying existing needs in donation education by applying principles learned from other public health education programs, and identifying roles that could be assumed to help strengthen the American public''s commitment to organ and tissue donation. These roles, which could be adopted by an transplant-related organization, were as broker of knowledge, producer of educational strategies, energizer through communications research, and catalyst by bringing together other groups. This approach to needs assessment and planning may provide useful insights both for those concerned with transplants and for professionals conducting education campaigns related to other public health issues.     

Morphologic assessment of oxidative damage: A review

Biochemical studies have indicated changes in anti-oxidant enzyme activities and increased oxidative damage products in many disease states, particularly aging and diseases associated with aging, such as neurodegenerative diseases and cancer. To try to determine cellular and subcellular localization of oxidative damage, our laboratory has developed quantitative light and electron microscopy immunogold techniques using specific antibodies to oxidative damage products. Results from studies of different pathologic processes are presented, illustrating that both localization and quantitation of oxidative damage products is possible. These analyses give important insights into the nature of various pathologic processes.