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.     

The impact of AIDS on state and local health departments: issues and a few answers.

Owing to large differences in the incidence of AIDS (acquired immunodeficiency syndrome) and in public health resources and priorities, the impact of AIDS on state and local health departments has been variable. Nonetheless, health departments everywhere are being held responsible for surveillance and control of the HIV (human immunodeficiency virus) epidemic which we believe requires, at minimum, convenient, free HIV testing and counseling; expanded HIV services in sexually transmitted diseases clinics and substance treatment centers; locally oriented AIDS information/education; notification of persons unknowingly exposed to HIV; restrictive measures for HIV-infected persons who, after counseling, persist in exposing others; regulation or closure of public establishments in which HIV transmission is likely to result; and confidential reporting of all HIV test results to public health departments. In Colorado new legislation was passed to require reporting of HIV test results, to provide the reports with near absolute protections against unauthorized disclosure, and to modify quarantine statues to incorporate rights to due process, appeals, and confidentially. States in which there is a legal basis for discrimination against gay men will need to rectify this problem first. There is no evidence that reporting of HIV infections in Colorado has adversely affected the rate at which persons with HIV risk behaviors volunteer to be tested. For Denver and Colorado Departments of Health, more than 70 per cent of the estimated $2,796,000 expended in AIDS activities during 1987 was federal.     

Age-dependent Responses to Thermal Hyperalgesia and Mechanical Allodynia in a Rat Model of Acute Postoperative Pain

Background: Developmental differences in short- and long-term responses to pain, especially surgical pain, have received minimal attention. The purpose of the present study was to examine postoperative responses in rats of developmental ages paralleling the infant to young adult human.

Methods: The withdrawal threshold to von Frey filament testing and withdrawal latency to hind-paw radiant heating were determined before and for various times after hind-paw incision in rats 2, 4, and 16 weeks of age. Control rats of these ages were observed serially without surgery.

Results: In control animals, younger rats were more sensitive to mechanical stimulation and less sensitive to thermal stimulation. Paw incision resulted in similar changes to both types of stimulation in all age groups, peaking 4 h after surgery. However, the return to normal sensitivity to mechanical stimulation, as measured by return of threshold to 80% of normal, occurred more quickly in 2-week-old than in 4- and 16-week-old animals. In contrast, there was no age difference for time to return to normal sensitivity to thermal stimulation after surgery.     

Membrane structure, toxins and phospholipase A2 activity.

The phospholipid-hydrolyzing enzyme phospholipase A2 (PLA2) (EC 3.1.1.4) exists in several forms which can be located in the cytosol or on cellular membranes. We review briefly cellular regulatory mechanisms involving covalent modification by protein kinase C and the action of Ca2+, cytokines, G proteins and other cellular proteins. The major focus is the role of phospholipid structure on PLA2 activity, including (1) the mechanism of PLA2 action on synthetic phospholipid bilayers, (2) perturbation of synthetic and cellular membranes with lipophilic agents and membrane-interactive peptides and (3) the ability of these agents to activate endogenous PLA2 activity, with emphasis on the venom and plant toxins melittin, cardiotoxin and Pyrularia thionein.     

Change management in a group dental practice. A consideration of management issues that may arise in a larger dental practice.

The drive for quality assurance in general dental practice has arisen as a response to changing standards and demands. Dentists need to develop skills in change management in this new culture of change. Groups of practitioners often encounter difficulties when managing change, yet it is essential that they lead the process. Such problems are common among groups of professionals. A wide range of topics is presented that may, from one point of view, represent challenging or problem areas (obstacles) for a group practice but may also, from a different point of view, provide a framework of opportunities for improvement, and facilitate the management processes within the practice and the management of change in particular (tools). The range of skills required to assist a professional group is such that individual dentists or advisers may not be able to achieve much on their own. The best way forward may be to interpret the problems as a professional training need and to organise training as a group. These issues will be considered under the following headings: partners and teams; introduction: the need for change management; the challenge for group practices; obstacles and tools; conclusion: the way forward--a case for training.