Predominant role of catalase in the disposal of hydrogen peroxide within human erythrocytes

Purified enzymes were mixed to form a cell-free system that simulated the conditions for removal of hydrogen peroxide within human erythrocytes. Human glutathione peroxidase disposed of hydrogen peroxide (H2O2) at a rate that was only 17% of the rate at which human catalase simultaneously removed hydrogen peroxide. The relative rates observed were in agreement with the relative rates predicted from the kinetic constants of the two enzymes. These results confirm two earlier studies on intact erythrocytes, which refuted the notion that glutathione peroxidase is the primary enzyme for removal of hydrogen peroxide within erythrocytes. The present findings differ from the results with intact cells, however, in showing that glutathione peroxidase accounts for even less than 50% of the removal of hydrogen peroxide. A means is proposed for calculating the relative contribution of glutathione peroxidase and catalase in other cells and species. The present results raise the possibility that the major function of glutathione peroxidase may be the disposal of organic peroxides rather than the removal of hydrogen peroxide.     

The identification of urinary bile alcohols by gas chromatography–mass spectrometry in patients with liver disease and in healthy individuals

Abstract. The neutral steroid fractions in the urine of eleven patients suffering from various forms of liver disease with cholestasis and of ten healthy individuals were studied by glass capillary gas chromatography-mass spectrometry. The steroid conjugates in urine were enzymatically solvolysed, the liberated steroids extracted and transformed into the trimethylsilylether for measurements.
The excretion rates of androstane and pregnane metabolites of patients with liver disease were far lower than those of healthy persons. The main compounds in the urine of the former were the bile alcohols 27 - nor -3α, 7α, 12α, 24, 25 - pentahydroxy - 5β - cholestane and 3α, 7α, 12α, 25, 26 - pentahydroxy - 5β - cholestane. Our data suggest a correlation between the excretion rates of these bile alcohols and the serum levels of bilirubin. While the excretion rate of the two bile alcohols in the urine of healthy individuals was approximately 0.24 mg/24 h (0.6 μmol/24 h) a patient with a serum bilirubin of 841 μmol/1 excreted 4 mg/24 h (9 μmol/24 h). The accumulation of bile alcohols described in this study possibly indicates alternative pathways of cholic acid formation in liver disease.     

Neurovascular coupling in humans: Physiology,methodological advances and clinical implications

Neurovascular coupling reflects the close temporal and regional linkage between neural activity and cerebral blood flow. Although providing mechanistic insight, our understanding of neurovascular coupling is largely limited to non-physiological ex vivo preparations and non-human models using sedatives/anesthetics with confounding cerebrovascular implications. Herein, with particular focus on humans, we review the present mechanistic understanding of neurovascular coupling and highlight current approaches to assess these responses and the application in health and disease. Moreover, we present new guidelines for standardizing the assessment of neurovascular coupling in humans. To improve the reliability of measurement and related interpretation, the utility of new automated software for neurovascular coupling is demonstrated, which provides the capacity for coalescing repetitive trials and time intervals into single contours and extracting numerous metrics (e.g., conductance and pulsatility, critical closing pressure, etc.) according to patterns of interest (e.g., peak/minimum response, time of response, etc.). This versatile software also permits the normalization of neurovascular coupling metrics to dynamic changes in arterial blood gases, potentially influencing the hyperemic response. It is hoped that these guidelines, combined with the newly developed and openly available software, will help to propel the understanding of neurovascular coupling in humans and also lead to improved clinical management of this critical physiological function.     

Molecular characterization of Wilms' tumor from a resource-constrained region of sub-Saharan Africa

Sub-Saharan African children have an increased incidence of Wilms' tumor (WT) and experience alarmingly poor outcomes. Although these outcomes are largely due to inadequate therapy, we hypothesized that WT from this region exhibits features of biological aggressiveness that may warrant broader implementation of high-risk therapeutic protocols. We evaluated 15 Kenyan WT (KWT) for features of aggressive disease (blastemal predominance and Ki67/cellular proliferation) and treatment resistance (anaplasia and p53 immunopositivity). To explore the additional biological features of KWT, we determined the mutational status of the CTNNB1/β-catenin and WT1 genes and performed immunostaining for markers of Wnt pathway activation (β-catenin) and nephronic progenitor cell self-renewal (WT1, CITED1 and SIX2). We characterized the proteome of KWT using imaging mass spectrometry (IMS). The results were compared to histology- and age-matched North American WT (NAWT) controls. For patients with KWT, blastemal predominance was noted in 53.3% and anaplasia in 13%. We detected increased loss to follow-up (p = 0.028), disease relapse (p = 0.044), mortality (p = 0.001) and nuclear unrest (p = 0.001) in patients with KWT compared to controls. KWT and NAWT showed similar Ki67/cellular proliferation. We detected an increased proportion of epithelial nuclear β-catenin in KWT (p = 0.013). All 15 KWT specimens were found to harbor wild-type CTNNB1/β-catenin, and one contained a WT1 nonsense mutation. WT1 was detected by immunostaining in 100% of KWT, CITED1 in 80% and SIX2 in 80%. IMS revealed a molecular signature unique to KWT that was distinct from NAWT. The African WT specimens appear to express markers of adverse clinical behavior and treatment resistance and may require alternative therapies or implementation of high-risk treatment protocols.     

聚焦超声与低温等离子治疗后兔鼻黏膜形态学分析

目的 观察聚焦超声与低温等离子对鼻黏膜形态学的影响程度及意义.方法 运用聚焦超声技术,在设定的剂量参数下对兔鼻甲进行直线扫描;运用低温等离子射频消融术对免鼻甲进行处理,在1个月及3个月后对两种方法处理后兔鼻甲切片及正常兔鼻甲切片进行对比观察,通过大体形态、光镜下观察对两种治疗方法兔鼻黏膜组织形态学的改变进行比较.结果 两种方法处理后1个月及3个月后兔鼻甲在外观和色泽无明显改变,光镜下显示兔鼻黏膜上皮层完整;运用低温等离子射频消融术处理后兔鼻甲外观较正常缩小,色泽灰白,且有分泌物存在,光镜下显示兔鼻黏膜上皮层断裂,部分切片上皮层完全消失.结论 在设定参数下聚焦超声可不破坏鼻黏膜上皮,可使鼻黏膜黏液纤毛系统功能得以完全保留.     

Ciliated hepatic foregut cysts in children

Ciliated hepatic foregut cyst (CHFC) is a rare foregut developmental malformation usually diagnosed in adulthood; however, rare cases have been reported in the pediatric population. CHFC can transform into a squamous cell carcinoma resulting in death despite surgical resection of the isolated malignancy. We report the presentation, evaluation, and surgical management of a symptomatic 17-year-old girl found to have a 6.5 × 4.5 cm CHFC and suggest that all patients with suspected CHFC undergo prompt evaluation and complete cyst excision.     

多轴向螺钉-棒椎弓根固定系统植入治疗寰枢椎损伤的特征

目的:总结应用多轴向钛螺钉-棒系统椎弓根钉植入技术治疗寰枢椎损伤的特点。方法:选择山东省东营市人民医院、加拿大脊柱外科中心、山东省立医院脊柱外科1999-01/2004-01治疗的寰枢椎损伤患者。应用后路多轴向钛螺钉-棒系统固定融合手术治疗38例,固定位置为寰椎(C1)的双侧块和枢椎(C2)的椎弓根,并与46例采用关节突螺钉复合后方椎板下钢丝固定植骨融合进行对比分析。结果:84例患者全部进入结果分析。①治疗组脊髓损伤的治愈率和总有效率(治愈 有效)高于对照组,但差异无显著性(92%,85%,χ2=0.29,P>0.05)。②治疗组对椎动脉孔的入侵率明显低于对照组(5%,30%,χ2=6.99,P<0.05)。③治疗组对椎管的入侵率明显低于对照组(5%,28%,χ2=6.02,P<0.05)。④术后治疗组α角(寰枢椎角)为(26.8±5.42)°,对照组α角为(25.6±5.82)°,两组对比差异无显著性(t=1.27,P>0.05)。⑤治疗组1例轻度错位(≤7mm),1例神经轻度放射痛,术后5个月取出内固定后消失,余无固定松动、椎动脉损伤、神经压迫征发生,3个月融合28例,6个月全部融合。对照组4例出现骨折所致不稳,3例半脱位,5例不融合,6例神经痛。结论:对急性寰、枢椎损伤患者进行C1双侧块和C2椎弓根后路多轴向钉-棒系统固定融合手术治疗方法简单、易于避开椎动脉,定位准确,直视下进行操作,安全性高,固定可靠。     

Personal genome testing: Test characteristics to clarify the discourse on ethical, legal and societal issues

Background

As genetics technology proceeds, practices of genetic testing have become more heterogeneous: many different types of tests are finding their way to the public in different settings and for a variety of purposes. This diversification is relevant to the discourse on ethical, legal and societal issues (ELSI) surrounding genetic testing, which must evolve to encompass these differences. One important development is the rise of personal genome testing on the basis of genetic profiling: the testing of multiple genetic variants simultaneously for the prediction of common multifactorial diseases. Currently, an increasing number of companies are offering personal genome tests directly to consumers and are spurring ELSI-discussions, which stand in need of clarification. This paper presents a systematic approach to the ELSI-evaluation of personal genome testing for multifactorial diseases along the lines of its test characteristics.

Discussion

This paper addresses four test characteristics of personal genome testing: its being a non-targeted type of testing, its high analytical validity, low clinical validity and problematic clinical utility. These characteristics raise their own specific ELSI, for example: non-targeted genetic profiling poses serious problems for information provision and informed consent. Questions about the quantity and quality of the necessary information, as well as about moral responsibilities with regard to the provision of information are therefore becoming central themes within ELSI-discussions of personal genome testing. Further, the current low level of clinical validity of genetic profiles raises questions concerning societal risks and regulatory requirements, whereas simultaneously it causes traditional ELSI-issues of clinical genetics, such as psychological and health risks, discrimination, and stigmatization, to lose part of their relevance. Also, classic notions of clinical utility are challenged by the newer notion of 'personal utility.'

Summary

Consideration of test characteristics is essential to any valuable discourse on the ELSI of personal genome testing for multifactorial diseases. Four key characteristics of the test - targeted/non-targeted testing, analytical validity, clinical validity and clinical utility - together determine the applicability and the relevance of ELSI to specific tests. The paper identifies and discusses four areas of interest for the ELSI-debate on personal genome testing: informational problems, risks, regulatory issues, and the notion of personal utility.     

Congenital diaphragmatic hernia repair on extracorporeal life support: a decade of lessons learned

Congenital diaphragmatic hernia (CDH) is a vexing anomaly that manifests with variable pulmonary compromise in neonates. More than one-third of neonates with CDH require extracorporeal membrane oxygenation (ECMO) for refractory pulmonary hypertension (PHN). To assess the outcome of neonates having CDH repair on ECMO, we reviewed our experience for babies treated between 1992 and 2003. Of 97 neonates with CDH, 40 required ECMO, and 30 were repaired on bypass. Eighteen were supported by veno-venous bypass (VV) and 12 by veno-arterial bypass (VA). While on ECMO, transfusion requirements increased twofold postoperatively (15 to 33 cc x kg(-1) day(-1), P = 0.03) and then significantly decreased after decannulation (1.5 cc x kg(-1) x day(-1), P < 0.01). Non-intracranial hemorrhage occurred in 7 (23%) infants and intracranial hemorrhage in 3 (10%). Twelve (40%) infants died; one (3%) on ECMO secondary to refractory PHN. The mean length of stay for the 18 (60%) survivors was 48 days. Comparisons between survivors and nonsurvivors showed a significantly increased mortality for infants placed on VA bypass (P < 0.01). However, no other variable was predictive of survival. We conclude that CDH repair on ECMO is technically feasible, shows similar survival to the Extracorporeal Life Support Organization (ELSO) registry, and is associated with few bleeding complications.