c-src gene product in developing rat brain is enriched in nerve growth cone membranes.

Differentiating rat neurons express high levels of the protooncogene product pp60c-src, a 60-kDa tyrosine kinase of unknown function encoded by c-src. pp60c-src was found to be concentrated at least 9-fold in membranes from a subcellular fraction of nerve growth cones, the motile tips of outgrowing neuronal processes. Indirect immunofluorescence staining of cultured chick retinal explants showed pp60c-src in neuronal growth cones and processes, with the antigen particularly concentrated in growth cones of long neurites. pp60c-src in growth cone membranes was an active tyrosine-specific protein kinase with elevated tyrosine-specific protein kinase activity and reduced electrophoretic mobility characteristic of the form of pp60c-src in central nervous system neurons. pp60c-src was present at lower levels in subcellular fractions from mature rat brain but synaptosomal membranes were not enriched. Preferential localization of an active form of pp60c-src in nerve growth cone membranes and persistence of pp60c-src in mature neurons suggest that this tyrosine kinase is important in growth cone-mediated neurite extension and synaptic plasticity.     

The human atrial strength-interval relation. Influence of cycle length and procainamide

We defined the atrial strength-interval relation in 23 patients at cycle lengths of 600, 450, and 300 msec before and after procainamide. The atrial diastolic threshold was similar at cycle lengths of 600 and 450 msec, but the threshold at 300 msec was significantly higher than that determined at 600 and 450 msec both before and after procainamide. Procainamide significantly increased the diastolic threshold only at a cycle length of 300 msec. The strength-interval relation was nonlinear, showing progressively decreasing decrements in the measured refractory period as the stimulating current was increased. Progressive decreases in the drive cycle length from 600 to 450 to 300 msec caused similar decreases in refractory periods. The shape of the curves was similar at cycle lengths of 600 and 450 msex. However, at low current strengths, the slope of the curve determined at 300 msex was significantly more vertical than the slopes of the curves at the longer drive cycle lengths. Procainamide caused similar increases in apparent refractory periods at each paced cycle length. Procainamide did not alter the shape of the curves at any paced cycle length. These observations confirm the importance of stimulation frequency on atrial excitability. They suggest that the effects of procainamide on the effective refractory period of the atrium are not cycle length dependent, although the drug effects on threshold are dependent on the drive cycle length.     

Treatment of infections of cerebrospinal fluid shunts

There is no unanimity at present concerning the best method of treatment of cerebrospinal fluid shunt-related infections. The most frequently used method includes removal of the shunt followed by antibiotic therapy and later replacement of the shunt. The experience at the University of Cincinnati during the past 15 years indicates that many shunt infections can be effectively treated without shunt removal. This report summarizes experiences with 11 consecutive ventriculoperitoneal shunt infections. These were treated by externalization of the peritoneal catheter followed by intraventricular and systemic antimicrobial therapy and by later replacement of the peritoneal catheter. The advantages of this method include the avoidance of two major operative procedures and the elimination of a period in which the intracranial pressure is not controlled. The need for externalization of the peritoneal catheter relates to the occurrence of localized peritoneal infection and pseudocyst formation, which prevents cure of the infection in many instances if the catheter is left in place. After follow-up periods of four months to five years, 10 of the 11 patients have apparently been cured of their infection.     

Radiotherapy for benign disease; assessing the risk of radiation-induced cancer following exposure to intermediate dose radiation

Most radiotherapy (RT) involves the use of high doses (>50 Gy) to treat malignant disease. However, low to intermediate doses (approximately 3–50 Gy) can provide effective control of a number of benign conditions, ranging from inflammatory/proliferative disorders (e.g. Dupuytren''s disease, heterotopic ossification, keloid scarring, pigmented villonodular synovitis) to benign tumours (e.g. glomus tumours or juvenile nasopharyngeal angiofibromas). Current use in UK RT departments is very variable. This review identifies those benign diseases for which RT provides good control of symptoms with, for the most part, minimal side effects. However, exposure to radiation has the potential to cause a radiation-induced cancer (RIC) many years after treatment. The evidence for the magnitude of this risk comes from many disparate sources and is constrained by the small number of long-term studies in relevant clinical cohorts. This review considers the types of evidence available, i.e. theoretical models, phantom studies, epidemiological studies, long-term follow-up of cancer patients and those treated for benign disease, although many of the latter data pertain to treatments that are no longer used. Informative studies are summarized and considered in relation to the potential for development of a RIC in a range of key tissues (skin, brain etc.). Overall, the evidence suggests that the risks of cancer following RT for benign disease for currently advised protocols are small, especially in older patients. However, the balance of risk vs benefit needs to be considered in younger adults and especially if RT is being considered in adolescents or children.     

Geriatric Care Boot Camp: An Interprofessional Education Program for Healthcare Professionals

In response to the need for interprofessional geriatrics education, a half‐day geriatric care boot camp for healthcare professionals was held that covered core concepts in geriatric medicine: delirium and dementia, medication management, palliative care, ethics, and a general overview of older adults. Aspects of the curriculum focused on interprofessional education, and the attendees and presenters were healthcare professionals from a wide variety of fields. Primary objectives were to determine changes in knowledge of core concepts in geriatrics and level of comfort in caring for older adults. Secondary objectives assessed whether participants found the interprofessional approach beneficial and whether they used or shared this information with others in their professional activities. Participants completed pre‐ and postassessment surveys. Changes in participant understanding of each core concept were statistically significant, as was the change in comfort level of participants in caring for older adults. Furthermore, attendees found the multidisciplinary perspective of the boot camp beneficial. A 3‐month follow‐up survey assessed whether attendees applied and shared information learned in their own professional activities. Half of the respondents who reported sharing universally shared core concepts. Delirium and dementia information was most frequently shared. Information was most frequently shared with students, nurses, and patients’ families. Attendees less frequently shared, or did not share, with physicians, physician assistants, social workers, physical and occupational therapists, nutritionists, and dentists. The healthcare professionals who may benefit greatly from future education programs are those with whom the boot camp information was least frequently shared; thus, they are appropriate targets for advertisements for future programs.     

Association between children's exposure to a violent event and objectively and subjectively measured sleep characteristics: a pilot longitudinal study

Although sleep disturbances are commonly reported among children exposed to violence, objective evidence of such disturbances is rare. This longitudinal, home‐based study assessed the effects of a known community‐ or family‐violence incident on both actigraphy‐derived and subjectively reported sleep outcomes of an ethnically mixed, urban sample of children aged 8–16 years. We hypothesized that increased event severity (child physical assault, witnessed homicide) would be associated with lower sleep duration and poorer sleep quality both at baseline and at 3‐month follow‐up. Covariate‐adjusted analyses based on a generalized estimating equations approach showed that children physically assaulted during the event showed lower sleep duration and sleep efficiency and greater wake after sleep onset than those not physically assaulted. Physically assaulted children were more likely to have a later bedtime than non‐assaulted children, but this difference decreased at 3 months. Children witnessing a homicide showed greater wake after sleep onset at baseline and reported greater sleep problems than those witnessing a non‐homicide event, but these differences decreased at 3 months. They were also somewhat more likely to have greater nightly variation in sleep duration. Collectively, results suggest that violence exposure influences children's sleep, but that specific dimensions of sleep may exhibit different susceptibility to different characteristics of violence, especially over time.