Biomedical subjects
L A Wheeler
Publications and source records attributed to L A Wheeler.
Alpha-2 adrenergic receptor agonists are neuroprotective in experimental models of glaucoma.
PURPOSE: The glaucomas are characterized by chronic progressive ganglion cell loss over many years. A drug with neuroprotective activity should increase the resistance of retinal ganglion cells (RGC) to chronic stress or injury and therefore enhance survival. Brimonidine is a highly selective and potent alpha-2 adrenergic receptor agonist, which lowers intra-ocular pressure (IOP) and is neuroprotective. Immunohistochemistry data have shown that the specific receptor targets, the alpha-2 receptors, are located in the inner retina. METHODS: Brimonidine 0.1 mg/kg given intraperitoneally promoted RGC survival compared with vehicle using the optic nerve crush model even when administered up to 24 hours before injury. Using the chronic ocular hypertensive rat model, brimonidine 1 mg/kg/day (with osmotic pump) significantly prevented the loss of RGCs when compared with vehicle or timolol. This ability was due to the neuroprotective action of brimonidine, since it did not affect IOP. In addition, brimonidine 0.1 mg/day reached concentrations in the retina of Sprague-Dawley rats within 30 minutes of injection, which was sufficient to activate the alpha-2 receptor (> or = 2 nM) and maintained these concentrations for 6 hours. CONCLUSIONS: Having demonstrated that: a. the specific receptor target of brimonidine is located in the retina, which is important for optic neuroprotection, b. the agent shows neuroprotective ability in animal models, c. pharmacological concentrations of the drug can be reached in the retina, clinical trial has been initiated to determine whether brimonidine is neuroprotective in patients with nonarteritic ischaemic optic neuropathy.
From the lab to the clinic: activation of an alpha-2 agonist pathway is neuroprotective in models of retinal and optic nerve injury.
PURPOSE: The selective alpha-2 agonist brimonidine was used as a pharmacological probe to activate alpha 2 receptor-mediated neuroprotective signaling pathways and quantitate the enhancement of retinal ganglion cell survival and function in animals with ischemic retinal and optic nerve injury. METHODS: Two animal models were used to achieve different methods of neuronal insult. The first model involved mechanical injury of the rat optic nerve after treatment with a single intraperitoneal (i.p.) dose of brimonidine or a control vehicle. The second model involving acute retinal ischemic/reperfusion injury was used in a variety of experiments in which rats were treated with either intraperitoneal brimonidine or single dose topical brimonidine at various strengths. In all cases retinal ischemia was induced and maintained followed by reperfusion. In some cases, TUNEL staining was performed on histologic sections of the retinas of rats that had been sacrificed after 24 hours. To examine the activation of neuronal survival pathways at the molecular level, rats were injected with i.p. brimonidine followed by the isolation of mRNAs from whole retinas 24 hours after ischemic injury. RESULTS: Intraperitoneal brimonidine enhanced rat RGC survival and function in the partial crush injury model, and neuroprotection was dose-dependent. Topical application of brimonidine 1 hour before injury was effective in decreasing ischemic retinal injury. Ischemic retinas treated with brimonidine resulted with a large decrease in TUNEL staining. CONCLUSIONS: Treatment with the alpha 2 adrenoreceptor agonist brimonidine was found to confer neuroprotection to retinal ganglion cells in two distinct models of neuronal injury resulting from acute retinal ischemia/reperfusion and calibrated optic nerve compression.
Computer-planned menus for patients with diabetes mellitus.
A computer program has been developed that has the capability to plan menus for diabetic patients. Program input includes the patient's diet prescription, usual daily meal pattern, and food preferences. The program uses a food selection algorithm that combines patient food preferences and randomization to produce menus that include foods the patient likes and that vary from day to day. The amount of each food item served at a meal is determined by an integer programming algorithm that satisfies the dietary prescription. Program output includes daily menus, weekly nutrient summaries, and a weekly shopping list. The menus includes for each food item: food name, amount in household units, numbers and types of exchanges, calories, and a space in which to write exchanges. The menu serves as a diet plan, exchange concept instructional model, and diabetic diary.
Evaluation of computer-based diet education in persons with diabetes mellitus and limited educational background.
A study was conducted to determine whether computer-based techniques for meal planning and diet education could be an effective supplement to diabetes diet counseling in a group of inner-city subjects with limited educational background. Sixteen individuals with diabetes mellitus who were newly referred to an inner-city outpatient diet clinic and who demonstrated ninth-grade reading ability were given computer-based nutritional education. They received meal planning information through use of individualized computer-planned menus and education about the diabetes diet by computer-assisted instruction (CAI) combined with an interactive videodisc system (VIDEO). Total contact time was 180 min of CAI/VIDEO, 50 min of dietitian/patient education, and 20 min of dietitian/patient computer time (the last function could have been performed by a clerk). At the end of 4 wk, the group performance was improved in Exchange Lists knowledge (P less than 0.001), recognition of foods containing concentrated carbohydrate (P less than 0.05), and reduction of reported fat intake (P less than 0.05). In addition, average group weight declined by 4.6 lb (P less than 0.005). No improvement was found in food-measuring skills or in calorie-consumption compliance during a standardized buffet lunch. It appears that computer-based techniques are an acceptable supplement to traditional methods of education in this patient group and can improve the effectiveness of diabetes education programs without a significant increase in dietitian time.
How do older nurses perceive their clinical competence and the effects of age?
In 1996, the first of the baby boomer population bulge that includes registered nurses (RNs) will reach age 50. Considering the prevailing negative stereotypes about women, nurses, and older adults in general, it is necessary to understand the abilities and needs of older nurses. This qualitative study was the first stage of a needs assessment of professionally mature RNs. Eight female RNs, employed full-time in an acute care setting and over age 50, were interviewed to determine their perceptions, attitudes, and beliefs about their own professional competence and how they believed they were perceived by others. Results indicated that older RNs felt good about themselves and the profession, and valued traditional bedside nursing and professional behaviors. Of the eight recurring themes found, the need for continuing education generated the most discussion. Will the methods and resources of the past meet the educational needs of the older nurses? Further study is recommended to discover their needs and the needs of their employers.