The concepts of successful and positive ageing.

Social scientists frequently refer to the 'greying' of the population in the west, the extension of the average lifespan to around the age of 76, and the projected increases in the numbers of people aged 85 and over, with the ensuing problems of chronic illness and disability that often accompany very old age. Increasing interest is being expressed in positive aspects of ageing: given the increases in life expectancy during this century, is it resulting in a life worth living? Concern is heightened by the estimate that, although most people aged 65+ live in their own homes and are relatively healthy and independent, years of disability can begin as early as 60 years. Conversely, some researchers and policy makers feel that enough time has been spent on the negative aspects of ageing and that the balance should be addressed by analysing successful, or positive ageing (sometimes defined in terms of an overlapping but separate dimension 'health-related quality of life'), with the aim of promoting well-being for future generations.

Nitric oxide is a mediator of the decrease in cytochrome P450-dependent metabolism caused by immunostimulants.

Bacterial lipopolysaccharide (LPS) and a diverse array of other immunostimulants and cytokines suppress the metabolism of endogenous and exogenous substances by reducing activity of the hepatic cytochrome P450 mixed-function oxidase system. Although this effect of immunostimulants was first described almost 40 yr ago, the mechanism is obscure. Immunostimulants are now known to cause NO overproduction by cells via induction of nitric oxide synthase.

Physiological characteristics of elite and club level female triathletes during running.

Most studies of the triathlon have looked at male triathletes with respect to the longer distance events such as the Hawaii Ironman Triathlon. The purpose of this study was to investigate and compare the physiological characteristics and training protocols of elite and competitive (club) women triathletes who compete at Olympic distance (1.5 km swim, 40 km cycle, 10 km run) to examine the relationship between these factors and running performance in the triathlon.

Development of specific antibody and in vivo response to antigen in different rat strains: effect of dexamethasone and importance of endogenous corticosteroids.

Endogenous glucocorticoids undoubtedly play a role in the control of immune responses: their contribution to inter-strain variation is unknown. The development of specific IgG and IgE was measured following inoculation with ovalbumin in Lewis, Fischer, Wistar and Brown Norway rats. The Lewis gives a smaller IgG and IgE response than the other strains and the response in vivo to antigen injected into the paw correlates with the titre of specific antibody.

Nifedipine inhibits accumulation of LDL and cholesterol in the aorta of the normocholesterolemic rabbit.

The effect of 5 days of oral nifedipine treatment (approximately 1 mg/kg per day in drinking water) on low density lipoprotein (LDL) and cholesterol accumulation in rabbit arteries was determined. Compared with control aortas, nifedipine treatment (n = 5) significantly reduced homologous 125I-tyramine cellobiose-LDL accumulation (control versus nifedipine: 45.93 +/- 4.

Investigations into the mechanism of vasoconstrictor action of the topical steroid betamethasone-17-valerate in the rat.

1. The effect of topical betamethasone upon skin blood flow was investigated in the rat. Two types of vasodilator stimuli were used; local heating to the surface of the skin and intradermal application of inflammatory agents.

Clonal heterogeneity in delayed decrease of plating efficiency of irradiated HeLa cells.

The clonogenic potential of progeny of irradiated HeLa cells was studied at different times after single doses of 4-12 Gy. The dose-dependent decrease in plating efficiency that was observed resembled the effect termed "delayed lethal mutation" by Seymour et al. (1986).

Effect of chronic capsaicin and guanethidine treatment on skin blood flow of the rat.

Using a non-invasive laser Doppler velocimetry technique to measure skin blood flow in the rat skin, we have shown that chronic treatment with capsaicin inhibited the vasodilator response to a non-pathological, local heat (44 degrees C, 20 min duration) stimulus. However, sympathectomy, accomplished with chronic treatment of guanethidine, had no effect on this heat-induced vasodilation. Topical steroids have also been shown to inhibit this response thus, since the heat-dilator response appears from these results to be brought about by the release of sensory neuropeptides, the sensory neuron may be a target for topical steroid action.

The effect of formal instruction in ophthalmoscopy on medical student performance.

Ophthalmoscopy is an essential part of a complete clinical examination of a patient. However specific formal instruction in fundoscopy is rarely given to medical students. We decided to determine the value of explicit teaching of ophthalmoscopy and devised and validated a rating scale for assessing performance which was used to evaluate 29 first year clinical medical student volunteers at St.

The effect of whole-body gamma-irradiation on localized beta-irradiation-induced skin reactions in mice.

The combined effects of whole-body radiation and localized radiation trauma have received scant experimental attention. However, in the recent accidents at Chernobyl and Goiania skin damage from beta-contamination was combined with total-body radiation and in many cases the skin lesions which covered large surfaces of the body were severe and recovery was prolonged. This paper models the immunosuppressive effects of whole-body gamma-radiation in the sublethal to lethal range (1-11 Gy) on the skin reactions produced by 50 Gy of superficial beta-radiation.

[The differences between interstitial pneumonia following whole-body irradiation and radiation-induced pneumonitis].

Clinical observations and experimental results suggest that radiation pneumonitis occurring after localised lung irradiation and interstitial pneumonia occurring after localised lung irradiation and interstitial pneumonia occurring after total body irradiation and bone marrow transplantation (no matter whether or not associated with cytomegalovirus infection) are two different pathological entities. They differ with regard to latency, pathogenesis, dose dependence, and probably dose distribution. Based on these considerations some recommendations on the planning of total body irradiation are made.

Lipolysis of triglyceride-rich lipoproteins activates coagulant factor XII: a study in familial lipoprotein-lipase deficiency.

A high factor VII coagulant activity (VIIc), a marker of increased risk of coronary heart disease, is frequently found in types IIb and IV hyperlipidaemia, but its cause is not fully understood. Factor VII can be activated by factor XIIa, generated from factor XII upon activation of the contact system of coagulation. Ten patients with familial lipoprotein-lipase (LPL) deficiency and 10 healthy control subjects were therefore compared to explore the hypothesis that high concentrations of unesterified fatty acids (UFA), released from triglyceride-rich lipoproteins by LPL, are a source of factor XII activation and hence the increased VIIc that is observed post-prandially and in non-LPL-deficient hypertriglyceridaemic states.

Second trimester amniotic fluid oestriol, dehydroepiandrosterone sulphate, and human chorionic gonadotrophin levels in Down's syndrome.

Objective: To investigate the reason for low maternal serum unconjugated oestriol (uE3) and raised human chorionic gonadotrophin (hCG) levels in Down's syndrome pregnancies.

Design: Measurement of uE3, total oestriol (tE3), dehydroepiandrosterone sulphate (DHEAS), a precursor of oestriol, and hCG in 15-20 week amniotic fluid samples from pregnancies with and without Down's syndrome.

Setting: The retrieval and use of stored amniotic fluid samples collected from women who had had an amniocentesis for antenatal diagnosis.

Rapid repopulation in radiotherapy: a debate on mechanism. Accelerated repopulation in tumours and normal tissues.

Accelerated repopulation is a well established response pattern of normal epithelial to fractionated irradiation. It is delayed until the tissue recognises functional injury. It is well regulated to maintain a steady state and continues until integrity of the tissue is restored.

Trends in prevalence and survival of very low birthweight infants, England and Wales: 1983-7.

Between 1983 and 1987 over 99% of all infants born in England and Wales had their birth weights recorded when the birth was registered. Trends in occurrence and one year survival of those who weighed under 1500 g at birth have been calculated in 100 g groups, separately for single and multiple births. By 1987 singleton live births in England and Wales who weighed between 700 and 799 g had a 43% chance of surviving to 1 year compared with a 32% chance five years earlier; those who weighed 800 to 899 g had a 55% chance compared with 46%.

Diphenylene iodonium, an inhibitor of free radical formation, inhibits platelet aggregation.

Diphenylene iodonium is an inhibitor of the enzyme NADPH-oxidase and prevents the generation of oxygen-derived free radicals in neutrophils (Cross and Jones, 1986). Here we show that diphenylene iodonium (0.25-2 microM) inhibited, according to the dose, thrombin-induced platelet-aggregation in human washed platelets and ADP-induced platelet aggregation in platelet-rich plasma.

Are our babies becoming bigger?

I have tried to show, using a contemporary international data set, the overall consistency in shape of curves of national birthweight distributions which reflect the biological and social characteristics of the population from which they are derived, and the effects of changes in these characteristics. For several countries, including the United States and England and Wales, the trends in recent years have been such as to shift the main distribution upwards, so that the median weight has increased. Also shown has been the close and specific relationship within each population group between infant mortality and birthweight, with sharp falls of mortality with increasing birthweight.

Maternal serum alpha-fetoprotein screening for open neural tube defects in twin pregnancies.

Data on maternal serum alpha-fetoprotein (AFP) levels at 13-24 weeks' gestation in 46 twin pregnancies with open neural tube defects (22 with anencephaly, 24 with open spina bifida) and 169 unaffected twins were used to estimate the detection and false-positive rates associated with different cut-off levels. Using the conventional cut-off level of 2.5 multiples of the median (MoM) for unaffected singleton pregnancies of the same gestation and laboratory, the detection rate in twins was 99 per cent for anencephaly and 89 per cent for open spina bifida, with a false-positive rate of 30 per cent.

Anti-thrombotic drugs in the treatment of coronary heart disease: the present situation with aspirin.

The most important clinical studies of acetylsalicylic acid in coronary heart disease are compiled. In early 1970 trials unnecessarily high doses have been used. Since 1980 acetylsalicylic acid was given in a dose of about 1000 mg/day.

Evidence of conformational changes in the non-equivalent binding sites of human serum transferrin.

Samples of monoferric human serum transferrin have been prepared in which the iron occupies predominantly the N-site (sample A) and the C-site (sample B). 111In was then added in concentrations small enough to ensure that there was always an excess of specific binding sites. Because of the presence of apo-transferrin in both the samples, the occupancy by 111In in the two sites was only 75-78% C-site in sample A and only 61-65% N-site in sample B.

Some optimum conditions for proton induced ultrasoft x-ray production.

The proton beam from an AN700 van de Graaff accelerator has been used to bombard solid targets of C, TiB2, SiC, SiN, Al and Au in the energy range 250-700 keV. A study of target surface contamination, the nature of the angular dependence in the x-ray emission and the dependence of the x-ray yield on proton energy has been undertaken. Our findings suggest that the optimum target angle is 30 degrees with respect to the incident proton direction and the detector angle 90 degrees to the target surface.

Cell kinetics and longitudinal bone growth in birds.

The theory that links cell division in epiphyseal cartilage plates to overall growth of long bones has been extended from linear growth systems to those in which proliferating and hypertrophied cells are not arranged in columns. Consideration has also been given to the analysis of non-parallel growth systems. The theory is illustrated by examples from the growth of chicken bones.

Application of an individually predicted dosage of amitriptyline to the treatment of depression.

The treatment of depressed patients with a fixed dose of amitriptyline is compared to treatment with an individualized dose calculated by means of a simple pharmacokinetic test. Clinical response and the development of side-effects are compared between the two groups of patients. Although the numbers in the groups were small, the clinical results lend little support to the concept of a therapeutic range of plasma drug concentrations for amitriptyline, and none of the plasma concentrations was high enough to produce serious toxic effects.