Simulation model of renal replacement therapy: predicting future demand in England.

BACKGROUND: The demand for renal replacement therapy (RRT) in England has risen steadily, although from a lower base than many other developed countries. Predicting the future demand for RRT and the impact of factors such as the acceptance rate, transplant supply and patient survival, is required in order to inform the planning of such services. METHODS: A discrete event simulation model estimates the future demand for RRT in England in 2010 for a range of scenarios. The model uses current prevalence and current and projected future acceptance rates, survival rates and the transitions between modalities to predict future patient numbers. National population and mortality data, published literature and data from the UK Renal Registry and UK Transplant, are used to estimate unmet need for RRT, the impact of changing demography and incidence of Type 2 diabetes, patient haemodialysis (HD) survival and transplant supply. RESULTS: By 2010 the predicted prevalence will have increased from about 30,000 in 2000 to between 42 and 51,000 (900-1000 p.m.p.), an average annual growth of 4.5-6%. Changing transplant supply has a small effect on overall numbers but changes the proportion of patients with functioning graft by up to 8%. Even with an optimistic increase in transplant supply (11% p.a. for 5 years), numbers on HD will continue to rise substantially, especially in the elderly. The factors most influencing future patient numbers are the acceptance rate and dialysis survival. CONCLUSION: This model predicts a substantial growth in the RRT population to 2010 to a rate approaching 1000 p.m.p., particularly in the elderly and those on HD, with a steady state not being reached for at least 25 years.     

Uterine stromal sarcoma cell line. A cytogenetic and electron microscopic study.

Uterine sarcomas constitute approximately 3% of all malignant uterine corpus tumors. Of these, the tumors that originate solely in the stromal elements of the uterine wall are relatively infrequent and have not been well characterized cytogenetically. We report data from a low-grade endometrial stromal sarcoma both at the time of resection and after months in long-term tissue culture. Cytogenetic analysis showed a clonal population of cells with an abnormal karyotype of 46,XX,del(5)(q31.1),der(7)t(6;7)(p21;p22) which remained unchanged in long-term culture. Electron microscopy suggests that these cells are similar to other neoplastic cells in having immature-appearing nuclei surrounded by a relatively mature cytoplasm (with well-developed organelles). Determination of the specificity of these observations must await study of additional stromal sarcomas.     

Are there any successful men from criminogenic backgrounds?

In the Cambridge Study in Delinquent Development, a prospective longitudinal survey of 411 London males, a vulnerable group of 63 boys from criminogenic backgrounds was defined on the basis of the best nonbehavioral predictors of delinquency at age 8-10 (low family income, large family size, convicted parents, low intelligence, and poor parental child-rearing behavior). These males were followed up to age 32, and the more successful men were defined according to criteria such as the absence of convictions and of other deviant behavior, good relationships with wives and children, and good accommodation and employment histories. Hence, "success" here refers to satisfactory social adjustment. The more successful men were those who had been neurotic at age 10, those who had few or no friends at age 8, those without convicted parents or behavior problem siblings, those with mothers who had a high opinion of their sons, and those who did not spend their leisure time with their fathers. At age 8-10 they were already better behaved and less daring than those later judged as the unsuccessful men. There was some tendency for shyness to act as a protective factor against delinquency for non-aggressive boys but as an aggravating factor for aggressive boys.     

Serological Cross-Reaction between Legionella pneumophila and Citrobacter freundii in Indirect Immunofluorescence and Rapid Microagglutination Tests

We describe the first case in which a diagnostic rise in titers of antibody to formalinized Legionella pneumophila serogroup 1 yolk sac antigen was shown to be caused by a cross-reaction between L. pneumophila and another organism, Citrobacter freundii.     

Mast cell phagocytosis of red blood cells.

The prevalence of mast cells infiltrating bone marrow of different rats varied widely, as did the staining properties and size of their cytoplasmic granules. Bone marrow mast cells from several rats revealed large membrane-limited inclusions which stained metachromatically or orthochromatically and resembled inclusions in some macrophages. Ultrastructurally, mast cells varied widely in content of uniform dense granules or enlarged granules with less dense, fine grained content. Some of the large inclusions observed ultrastructurally in mast cells were heterophagic vacuoles which contained erythrocytes or reticulocytes, or remnants from other phagocytized cells, possibly neutrophils or unidentified homogeneous material. Smaller bodies, interpreted as fragments of erythrocytes, lay extracellularly near mast cells and occupied small, membrane-limited, heterophagic vacuoles in some mast cells. In other mast cells, communal vacuoles enclosed several specific cytoplasmic granules in various stages of disruption. The communal vacuoles occasionally opened to the extracellular space. A few large indeterminate vacuoles in mast cells contained amorphous flocculent matter which apparently derived either from coalescence of cytoplasmic granules through fusion of granule membranes or from endocytosis.     

Epidemiology of transmissible diseases after elimination

Elimination of an infectious disease is often understood to mean the total absence of cases in a population. This situation can occur only if the entire population is immune as a result of either natural disease or vaccination. However, this costly and unrealistic scenario is not necessary to ensure elimination, more appropriately defined as a situation in which sustained transmission cannot occur and secondary spread from importations of disease will end naturally, without intervention. The authors describe the size and duration of outbreaks caused by imported infections after indigenous transmission has been eliminated. They show that the status of the elimination process can be monitored by assessing the proportion of cases imported and the distribution of outbreak sizes. Measles in Canada, the United States, and the United Kingdom provides a good example of the relevance of these criteria. Surveillance of the size and duration of these outbreaks enables maintenance of elimination to be monitored.     

Epidemiology of juvenile violence

It is difficult to review the epidemiology of juvenile violence because few studies focus specifically on this topic as opposed to childhood aggression or delinquency in general. More research is needed specifically on juvenile violence, which is generally measured using official records or self-reports. Self-report research shows that a substantial fraction of the male juvenile population commits violence, and that very few violent acts are followed by arrests or convictions. Racial differences in violence may be explainable by reference to racial differences in community contexts. There is a great deal of versatility in juvenile violence. Juveniles who commit one type of violent offense also tend to commit other types and nonviolent offenses. Violent offenders tend to be persistent or frequent offenders, and there is little difference between violent offenders and nonviolent but equally frequent offenders. Nevertheless, there is some degree of specialization in violence. More research is needed to investigate whether risk factors exist for violence that are not risk factors for serious nonviolent delinquency (e.g., biologic factors). Violent juveniles tend to have co-occurring problems such as victimization, substance abuse, and school failure. Often, they might be described as multiple-problem youth. There is considerable continuity from childhood aggression to juvenile violence. An early age of onset of violence predicts a large number of violent offenses. The major long-term risk factors for juvenile violence are individual (high impulsiveness and low intelligence, possibly linked to the executive functions of the brain), family (poor supervision, harsh discipline, child physical abuse, a violent parent, large family size, poverty, a broken family), peer delinquency, gang membership, urban residence, and living in a high-crime neighborhood (characterized by gangs, guns, and drugs in the United States). More research is needed on interactions among risk factors, and especially on interactions between biologic and psychosocial risk factors. Important short-term situational factors include motives of potential offenders (e.g., anger, a desire to hurt), alcohol consumption, and actions leading to violent events (e.g., the escalation of a trivial altercation). More specific research is needed on protective factors against youth violence, for example, by investigating why aggressive children do not become violent juveniles. More research is also needed on the development and validation of risk assessment instruments. To investigate developmental and risk factors for juvenile violence, longitudinal studies are needed. Such studies should include multiple cohorts, to draw conclusions about different age groups, and should include both boys and girls and the major racial and ethnic groups. They should measure a wide range of risk and especially protective factors. They should be based on large, high-risk samples, especially in inner-city areas, incorporating screening methods to maximize the yield of violent offenders while simultaneously making it possible to draw conclusions about the total population. They should include long-term follow-up studies to permit conclusions about developmental pathways. They should make a special effort to study careers of violence and to link developmental and situational data. It will not be easy to mount new longitudinal studies focusing specifically on juvenile violence, but such studies are needed to advance knowledge about the epidemiology of juvenile violence, including risk factors and developmental pathways.