B-cell lymphoproliferative disorders in children after bone marrow transplantation: radiologic manifestations

The radiographic findings in five pediatric patients in whom unregulated B-cell lymphoproliferative disorders developed following bone marrow transplantation are described. Four patients received T-cell-depleted bone marrow from mismatched donors and one received nondepleted marrow from a matched sibling donor. These disorders are similar to B-cell lymphoproliferative disorders that have been described in other immunosuppressed hosts. They are associated with Epstein-Barr virus and range from polyclonal proliferation without cytogenetic abnormalities to monoclonal lymphoma with clonal cytogenetic changes. Unlike other postallograft lymphoproliferative processes, B-cell lymphoproliferative disorders in these patients have not responded to antiviral therapy, immunologic therapy, or chemotherapy. The radiographic patterns of disease include diffuse or focal hepatic involvement; gallbladder wall thickening; and pulmonary, soft-tissue, and basal-ganglion masses. These radiologic findings are not specific and evaluation of tissue histology is required for diagnosis.     

预测急性呼吸窘迫综合征发生及死亡的临床指标:红细胞输注的潜在作用

急性呼吸窘迫综合征(acute respiraory distress syndrome,ARDS)是一种常见的严重肺功能紊乱的肺部并发症。常并发于脓毒血症、创伤和抽吸术等严重损伤后。ARDS的发生及死亡率可因发生ARDS损伤类型的不同而有差别,提示ARDS的发病机制和预后因临床风险因素而不同。最近,对重症病人进     

Comparison of inhibitors of superoxide generation in vascular smooth muscle cells

Background and purpose:

We compared the dose-dependent reductions in cellular superoxide anion (O₂⁻) by catalytic agents: superoxide dismutase (SOD), polyethylene glycol (PEG)-SOD and the nitroxide 4-hydroxy-2,2,6,6,-tetramethylpiperidine-1-oxyl (tempol) with uncharacterized antioxidants: 5,10,15,20-tetrakis (4-sulphonatophenyl) porphyrinate iron (III)(Fe-TTPS), (-)-cis-3,3′,4′,5,7-pentahydroxyflavane (2R,3R)-2-(3,4-dihydroxyphenyl)-3,4-dihydro-1(2H)-benzopyran-3,5,7-triol (-epicatechin), 2-phenyl-1,2-benzisoselenazol-3(2H)-one (ebselen) and N-acetyl-L-cysteine (NAC) with the spin trap nitroblue tetrazolium (NBT) and with the vitamins or their analogues: ascorbate, α-tocopherol and 6-hydroxy-2,5,7,8-tetramethylkroman-2-carboxy acid (trolox).

Experimental approach:

O₂⁻ was generated in primary cultures of angiotensin II-stimulated preglomerular vascular smooth muscle cells from spontaneously hypertensive rats and detected by lucigenin-enhanced chemiluminescence.

Key results:

SOD, PEG-SOD, NAC and tempol produced a similar maximum inhibition of O₂⁻ of 80–90%. -Epicatechin, NBT, ebselen and Fe-TTPS were significantly (P < 0.0125) less effective (50–70%), whereas trolox, α-tocopherol and ascorbate had little action even over 24 h of incubation (<31%). Effectiveness in disrupted and intact cells was similar for the permeable agents, PEG-SOD and tempol, but was enhanced for SOD. Generation of O₂⁻ was increased by NAC and NBT at low concentrations but reduced at high concentrations.

Conclusions and implications:

Maximum effectiveness against cellular production of O₂⁻ requires cell membrane permeability and catalytic action as exemplified by PEG-SOD or tempol. NAC and NBT have biphasic effects on O₂⁻ production. Vitamins C and E or analogues have low efficacy.     

Renal transplantation in the United Kingdom for patients from ethnic minorities

BACKGROUND: To investigate any differences in access to transplant and post-transplant outcomes for ethnic minority patients in the United Kingdom, national data on ethnicity of patients on the waiting list, those receiving a transplant, and deceased donors were analyzed. METHODS: Adult patients and donors were included. Ethnic origin was classified as white, Asian, black, or "other." National data were analyzed, and 2001 U.K. National census data were used for comparative purposes. Median waiting times to transplant were obtained from Kaplan-Meier estimates for patients registered 1998-2000. Transplant survival was estimated for patients transplanted from 1998 to 2003. RESULTS: A total of 92% of the U.K. population was white, compared with 77% of waiting list patients, 88% of transplant recipients, and 97% of deceased donors. Median waiting time to transplantation for white patients was 719 days (95% confidence interval 680-758) compared with 1368 (1131-1605) days for Asian patients and 1419 (1165-1673) days for black patients. The degree of human leukocyte antigen matching achieved was inferior for Asian and black patients. There is some evidence of inferior 3-year transplant survival for black patients compared with white and Asian patients (P=0.03). CONCLUSIONS: There are imbalances in the ethnic make up of the waiting list, the donor pool, and renal transplant recipients. There are significant differences in both post-transplant outcomes and time to transplantation between patients of different ethnic origin. Waiting times are influenced by allocation schemes, and the 2006 U.K. National Kidney Allocation Scheme is designed to achieve greater equity of access to transplant for all patients, regardless of geography, blood group, or ethnicity.     

Biochemistry of the induction and prevention of lipoperoxidative damage in human spermatozoa

Lipid peroxidation occurs in human sperm cells with damage to the cell plasma membrane, leading to loss of cytosolic components and hence to cell 'death'. The peroxidation may be induced at high rates in the presence of Fe2+ and ascorbate. It occurs at slower rates under physiological conditions as spontaneous lipid peroxidation, which has the following characteristics. The rate is constant over the time required for complete loss of motility in the cells of the sperm sample; one can thus use the time to complete loss of motility (TLM) as a ready measure of the rate. Loss of motility occurs at a characteristic extent of lipid peroxidation, assayed in terms of production of the peroxidative breakdown product, malonaldehyde (MA), that is independent of peroxidation rate. For human sperm, this extent corresponds to 0.1 nmol MA/10(8) cells. Human spermatozoa possess the anti-lipoperoxidative defence enzymes, superoxide dismutase (SOD) and glutathione peroxidase plus glutathione reductase (GPX/GRD). The SOD activity is highly variable between human sperm samples while the activities of GPX and GRD are rather more constant. The rates of production of superoxide anion, O2-, and hydrogen peroxide, H2O2, from human spermatozoa are variable, but their sum calculated in O2- equivalents as O2- + 2H2O2 is quite constant. The variability arises from the variability in SOD activity: all H2O2 produced is from O2- due to the action of SOD. The essential role of SOD as defence enzyme is inferred from the observation that TLM of a given sperm sample is directly proportional to the SOD activity of that sample. The essential role of GPX/GRD is inferred from the observation that inhibition of GPX, either with mercaptosuccinate or with complete oxidation of intracellular reduced glutathione, results in a 20-fold increase in peroxidation rate. The capacity of the GPX/GRD system appears to be limited by the glucose-6-phosphate dehydrogenase-catalysed rate of production of NADPH, the required reductive substrate for GRD. Human spermatozoa appear to have enough anti-lipoperoxidative defensive capacity for lifetimes long enough for fertilization but still short enough for ready removal from the female reproductive tract in good time. Too low a defence capacity could lead to male infertility.      

Knowledge,attitude and behaviour regarding dietary salt intake among medical students in Angola

High salt (sodium chloride) consumption is an important determinant of high blood pressure and cardiovascular risk. According to World Health Organisation (WHO) statistics, over 80% of cardiovascular disease (CVD) deaths take place in low-and middle-income countries, and elevated blood pressure levels were a major cause of these CVD deaths in those countries.1 Lifestyle factors such as unhealthy diet, physical inactivity, tobacco use and harmful use of alcohol have been considered the most important behavioural risk factors for heart disease and stroke.2Among dietary factors, high salt intake has been the most strongly associated with raised blood pressure and increased risk of stroke and CVD.3 Therefore dietary sodium restriction has been recommended as a non-pharmacological approach to blood pressure lowering,4-6 and for the prevention and control of non-communicable diseases at the population level.7,8Cumulative evidence has shown that even a modest reduction in salt intake was associated with blood pressure lowering and therefore with a significant reduction in incidence of cardiovascular events.9-12 Furthermore, data from the most recent systematic review and meta-analyses has shown the benefit of lowering sodium intake in apparently healthy adults and children,13 and in both hypertensive and normotensive individuals, irrespective of gender and ethnic group.9Since hypertension is associated with CVD worldwide, a public health intervention to reduce high blood pressure must target the role of lifestyle, particularly reduced sodium intake.7 Therefore, several countries have initiated strategies to reduce dietary salt intake in the general population by a combination of various procedures such as public education, food labelling, and collaboration with the food industry to reduce the salt content of processed food.14Among sub-Saharan African countries, only Nigeria and South Africa have developed dietary guidelines regarding salt intake.15 Recently, the South African government implemented important specific legislation towards decreasing salt intake in the population by reducing sodium content of processed foods by industries.16 Therefore, the current public health recommendation is that countries should launch national initiatives to reduce the over-consumption of salt as part of non-communicable disease prevention and healthy nutrition policies for limiting salt intake to less than 5 g/day for the general population including children.7 Despite of this guideline, however, high sodium intake remains prevalent around the world, with average daily salt intake varying from 5 to 18 g/day per person.17Although processed foods have been found to be the principal source of excessive dietary salt intake,18 sources of dietary sodium vary largely worldwide and may be influenced by cultural context and dietary habits of the population.19 In sub-Saharan African countries experiencing demographic and epidemiological transition, the rapid rise in prevalence of CVD (chiefly hypertension) has been attributed to lifestyle change, including high dietary sodium intake.20,21 However, consistent data from studies on risk factors are lacking for the majority of these countries.With regard to Angola, available data from a cross-sectional study reported a high prevalence of multiple cardiovascular risk factors, such as hypertension, sedentary lifestyle, electrocardiographic left ventricular hypertrophy,22 and high rate of the metabolic syndrome23 in an apparently healthy middle-aged population of university public employees living in urban and peri-urban areas.Determining the level of sodium intake in the population is crucial to establish intervention strategies and policy on reduction of sodium intake. For medical students in particular, it is very important to assess their awareness regarding dietary salt intake, since they are the future providers of healthcare information for the counselling of people about the need to reduce salt consumption. The aim of this study was to determine salt intake and to assess the knowledge, attitude and behaviour regarding dietary salt among medical students.