Blur adaptation: clinical and refractive considerations

The human visual system is amenable to a number of adaptive processes; one such process, or collection of processes, is the adaptation to blur. Blur adaptation can be observed as an improvement in vision under degraded conditions, and these changes occur relatively rapidly following exposure to blur. The potential important future directions of this research area and the clinical implications of blur adaptation are discussed.     

General practitioners: child accident prevention and 'The Health of the Nation'

It has recently been suggested in the ‘Health of the Nation’that specific accident prevention activities should be undertakenby general practitioners. This study reports the findings froma survey of general practitioners in Nottinghamshire assessingknowledge, attitudes and current practices in accident prevention.The findings suggest that more than two-thirds of respondinggeneral practitioners are aware of the extent of childhood mortalityfrom accidental injuries and of the risk factors for accidentalinjury. Knowledge scores were higher for women, those aged 44years and under, those on the child health surveillance list,those with experience of hospital or community paediatrics,and those with postgraduate qualifications in paediatrics. Morethan 50% of general practitioners hold positive views towardsthe activities suggested in the ‘Health of the Nation’and more than 40% are already carrying out such activities.Positive attitudes are more commonly held in women and thoseon the child health surveillance list. There was a significantcorrelation between knowledge score and attitude score. Forall accident prevention activities covered in the questionnaire,fewer practitioners undertook an activity than held a positiveattitude towards that activity. Accident prevention work iscurrently more likely to be undertaken by general practitionerson an opportunistic basis than on a systematic population basis.If general practitioner intervention is demonstrated to be effective,a shift towards a population approach may be more successfulin reducing injury rates.     

A "grapple hook" technique using a deflectable tip catheter to facilitate complex proximal circumflex interventions.

We present two patients with angulated, proximal left circumflex lesions, one a chronic total occlusion and one an acute subtotal occlusion. In both cases, use of the deflectable tip Venture Catheter (Velocimed, Minneapolis, MN) facilitated guide wire passage and successful percutaneous coronary intervention (PCI) after prior attempts at guide wire passage with standard wires were unsuccessful.     

The Surgeon General's warnings in outdoor cigarette advertising. Are they readable?

Outdoor advertising media represent a major vehicle by which cigarette companies promote their products. We investigated the readability of the Surgeon General's warning in cigarette advertisements (ads) in two outdoor media: billboards and taxicab ads. In an experiment in metropolitan Atlanta under typical driving conditions, observers were able to read the entire health warning on 18 (46%) of 39 street billboards but on only two (5%) of 39 highway billboards. In contrast, the content of the ads (ie, brand name, other wording, and notable imagery) could be recognized under the same conditions on more than 95% of the billboards. In a similar study of 100 taxicab cigarette ads in New York City, observers were unable to read the health warning in any of the ads but were able to identify the brand name in all ads and notable imagery in 95% of the ads. Significant differences between the readability of the warning and identification of the advertising content persisted even when partially read warnings were considered to have been read. We conclude that the Surgeon General's warning is not readable in its current form in the vast majority of billboard and taxicab ads. Factors contributing to unreadability include the small size of the letters, the excessive length of the warnings, the distance between the viewers and the ads, and movement between the viewers and the ads.     

Injury prevention programmes in primary care: a high risk group or a whole population approach?

OBJECTIVE: To examine the relationship between risk factors for childhood unintentional injury and injury outcome and to assess the feasibility of using risk factors to identify children at high risk of injury. SETTING: One general practice in Nottingham, UK. METHOD: A postal questionnaire survey to all parents of children registered with the practice (n = 771) to obtain data on risk and sociodemographic factors. All children still registered with the practice one year later were followed up for occurrence of a medically attended injury. RESULTS: The response rate was 78%. The injury rate over the follow up year was 246 injuries per 1000 children. Previous medically attended injury was associated with each of the injury outcomes (odds ratio (confidence interval) for all attendances, 2.33 (1.37 to 4.05); for accident and emergency attendances, 2.27 (1.15 to 4.4); and for primary health care team attendances, 2.58 (1.33 to 5.0)). Male sex was associated only with accident and emergency department attendance (odds ratio 2.13 (1.06 to 4.2)). Maternal age and previous injury were associated with a higher number of injuries in the subsequent year on univariate and multivariate analyses. The sensitivity and positive predictive value of the risk factors were low, except for previous injury and male sex. The number of children needing an injury prevention intervention to prevent one injury as identified by the risk factors was not significantly different from that required if a whole population approach were to be used. CONCLUSION: Primary care based injury prevention programmes, at present, should not be targeted at children identified as being at 'high risk' of injury. Nevertheless, a larger study using a wider cross section of the population is needed to address this issue further.     

Importance of progesterone and estrogen priming for the induction of maternal behavior by vaginocervical stimulation in sheep: effects of maternal experience

The effects of treating ovariectomised nulliparous and multiparous ewes with progesterone and estrogen on maternal behavior with or without vagino-cervical stimulation were investigated. Following 48 h of estrogen treatment there was neither evidence for stimulation of maternal behavior, nor a reduction in aggressive behavior, towards lambs by either multiparous or nulliparous ewes compared with control treatment (injections of the oil vehicle). Following 5 min of mechanical vaginocervical stimulation, the multiparous estrogen-treated ewes showed both positive maternal responses (low pitch bleats, licking, sniffing and approaching the lamb) and a reduction in aggression (butts) and negative behavior (withdrawal from the lamb) towards the lambs, whereas the nulliparous ewes showed only a reduction in aggression and negative behavior. Neither group showed positive maternal responses following vaginocervical stimulation without steroid priming. When the ewes received two weeks of progesterone priming prior to estrogen treatment, both multiparous and nulliparous ewes showed reduced aggression towards, and withdrawal from, the lambs compared to the control condition, but no positive maternal responses apart from an increased sniffing of the lamb. After vaginocervical stimulation positive maternal responses showed by multiparous ewes were significantly potentiated compared to those shown following estrogen treatment alone. Nulliparous ewes remained unresponsive on positive maternal behaviors. These studies show that hormonal priming has little effect in inducing the onset of maternal behavior in multiparous or nulliparous sheep but is an essential prerequisite for vaginocervical stimulation to do so in multiparous animals.     

Vasoconstrictor Fibre Discharge to Skeletal Muscle,Kidney, Intestine and Skin at Varying Levels of Arterial Baroreceptor Activity in the Cat

Estimations of the average discharge rates in vasoconstrictor fibres to skeletal muscle, kidney, intestine and skin at varying levels of arterial baroreceptor activity were made by comparing quantitatively the reflexly induced vascular responses with those obtained with stimulations of the regional vasoconstrictor fibres at known frequencies. The results indicate that withdrawal of baroreceptor restraint was normally followed by a considerably lower firing rate in renal vasoconstrictor fibres than in e.g. skeletal muscle vasoconstrictor fibres. A complete elimination of the inhibitory influence induced vasoconstrictor fibre discharge rates up to 8 imp/s in skeletal muscle but only at most 4 imp/s in the kidney. Intestinal vasomotor fibres were found to be activated to approximately the same extent as those to skeletal muscle. The vasomotor fibres to the cutaneous arterio-venous anastomoses were evidently not activated when the baroreceptors were unloaded. The reason for this non-uniform activation of the different sets of vasoconstrictor fibres seems to be different levels of spontaneous activity in the respective “neuron pools” in the bulbar vasomotor centre. The renal vascular responses to baroreceptor unloading became augmented when the excitatory level in the vasomotor centre was enhanced, as e.g. when the animal became acidotic.