Two methods are described for measuring the filtration coefficient of individually perfused frog mesenteric capillaries. Both methods involve the perfusion of capillaries via a micropipette with a solution in which a small number of human red cells are suspended. After a short period of perfusion, the capillary is occluded at a point some 500 ,um or more downstream from the point of cannulation. Movements of the red cells in the isolated capillary micropipette system are interpreted to be the consequence of fluid movements across the capillary wall. The filtration coefficient of the capillary is determined either (method I) from a series of different filtration rates measured at different capillary hydrostatic pressures when intracapillary colloid osmotic pressure is constant, or (method II) from the changes in filtration rate as the fluid within the capillary concentrates at a constant pressure. Values for the filtration coefficient obtained by both methods have a skewed distribution. Determinations made by method I at 14-16°C have a peak value of 2 x 10-3 vm.sec-1 . cm H20-1 and determinations made by method II at 22-26°C have a peak value of 5 x 10-3sjm . sec-. cm H20 -1.The assumptions underlying both methods are discussed and a mathematical model of the change in protein concentration in a closed off capillary at constant pressure is presented in the appendix.In 1927, Landis reported the first quantitative measurements of the rate of filtration and reabsorption of water across the capillary walls. He occluded single capillaries of the frog mesentery with a glass micro rod and observed that on some occasions red cells within the capillary moved towards the point of occlusion and on other occasions they moved away from it. He deduced that a red cell moved towards the point of occlusion when fluid was filtered across the capillary wall out of the column of plasma between that red cell and the point of occlusion. When fluid was reabsorbed from the tissues into the plasma, the column of plasma in an occluded capillary expanded leading the suspended red cells to move away from the site of occlusion. Measuring the capillary pressure by direct micropuncture, Landis was able to obtain a correlation between the rates of filtration and reabsorption of fluid across capillary walls and the capillary pressure. In this way he estimated an average figure for the filtration coefficient or hydraulic conductivity of the capillary wall for a population of capillaries.In

Background  Mental health problems are known to be hard to recognize in people with intellectual disabilities. One factor that may contribute to this is the diagnostic overshadowing bias, which describes the tendency of the clinicians to overlook symptoms of mental health problems in this client group and attribute them to being part of ‘having an intellectual disability’. Although a small amount of research has investigated this in the USA, very little has taken place in the UK. Materials and methods  Two clinical vignettes were produced. Both described identical clinical problems, except that one vignette described a man with an IQ of 58 and impaired social functioning (i.e. an intellectual disability) and one a man with an IQ of 108 and normal social functioning (i.e. non‐intellectually impaired). Psychiatrists (n = 274) and clinical psychologists (n = 412) throughout UK were randomly assigned to either the low IQ or normal IQ condition, and sent a corresponding clinical vignette. Results  One hundred and thirty‐three psychologists and 90 psychiatrists responded. Diagnostic overshadowing did appear to be present. Clinicians were more likely to recognize a range of symptoms in those with IQs in the normal range than those with intellectual disabilities. Furthermore, psychiatrists appeared more likely to make this error under some circumstances than clinical psychologists. Conclusions  Diagnostic overshadowing may contribute to the difficulties that mental health professionals commonly experience in identifying mental health problems in people with intellectual disabilities. However, the methodology commonly used in this type of research has a number of weaknesses, and would benefit from an alternative approach.

SUMMARY1. Individual capillaries of the transilluminated frog mesentery have been perfused with suspensions of human red cells in frog Ringer solution containing 1 -0 g albumin 100 ml.-'. The outer surface of the mesentery has been washed with normal frog Ringer solution and with frog Ringer solutions made hypertonic by addition of one of the following solutes: sodium chloride (100 m-mole. 1.-'); urea (100 m-mole. 1.-'); sucrose (20-50 m-mole. 1.-'); cyanocobalamin (8.5 m-mole. 1.-1). The temperature of the mesentery was between 14 and 160 C in all experiments.2. With the mesentery superfused with normal Ringer, the filtration coefficient was determined from measurements of the rate of fluid filtration across the capillary wall, at a series of known capillary pressures (Michel, Mason, Curry & Tooke, 1974). Filtration coefficient varied from 0-69 x 10-3 to 4-45 x 10-3 ,m. sec-'. cm H2 0-' with an average value of 1-87 x 10-3 ,um. sec-'. cm H20-1.3. When the superfusate was made hypertonic by the addition of a test solute, the osmotic reflexion coefficient (Ci) of the capillary wall to test solute was calculated from the additional rate of filtration, the concentration of test solute in the superfusate and the filtration coefficient. Average values for Ci were: sodium chloride, 0-068 + 0-03 (three capillaries); urea, 0-071 W0-015 (four capillaries); sucrose, 0-115+-0-023 (seven capillaries); cyanocobalamin, 0-100 + 0-03 (three capillaries).

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As the population of older adults increases, it is important to understand what may assist every older person to live well and longer. Using a systematic review, this study examined the longitudinal consequences of self-perceptions of aging (SPA), a measure of internalized stereotypes of aging, in participants 50 years or older. The sample comprised 21 studies published in English that used the Attitudes Toward Own Aging (ATOA) scale to measure SPA. Studies were conducted in the United States (10), Germany (7), Australia (2), and one each from Israel and Switzerland. Risk of bias was low, study design and assessment showed good to high quality, and the ATOA scale was reliable in all studies. Primary outcomes were physiological (N = 15; longevity and better health, health behaviors, and diseases) and psychological (N = 6; depression, cognitive function, and other psychological outcomes) rather than social. More positive SPA was consistently associated with healthier longitudinal outcomes, including better self-rated health and less obesity, greater longevity, better performance of the activities of daily living, less depression, and better cognitive functioning (including reductions in cognitive decline and incidence of dementia). These were both direct and indirect pathways and provide support for the consequences of aging stereotypes, providing support for Levy's Stereotype Embodiment theory. The results have public health implications, broadly as community messaging about the benefits of positive SPA and usual and healthy aging, and more narrowly in using ATOA to screen for middle-aged adults with negative SPA to prevent future physical and psychological decline.