Indications and outcomes of strabismus repair in visually mature patients

OBJECTIVE: To identify and examine the indications, outcomes and potential risks of strabismus surgery in visually mature patients. DESIGN: Case series. SETTING: University-based referral practice in Edmonton. PATIENTS: A total of 222 patients (115 females and 107 males) aged 9 to 69 (mean 29) years who underwent strabismus surgery for various types of strabismus (as grouped by original diagnosis). All patients were followed for at least 6 weeks postoperatively. OUTCOME MEASURES: Previous surgery and deviation in prism dioptres (delta) (distance and near), sensory status (measured by the Titmus stereotest at near) and the presence of symptoms (diplopia, abnormal head posture or asthenopia), recorded preoperatively, 6 weeks postoperatively and at the last postoperative visit. RESULTS: The patients were followed for an average of 14 months postoperatively. At the last postoperative visit 187 patients (84%) were aligned to within 15 delta of orthotropia. Overall, 116 patients (52%) demonstrated some degree of stereopsis postoperatively, compared with 78 (35%) preoperatively. A total of 116 patients (52%) had symptoms preoperatively, including diplopia, abnormal head posture or asthenopia; 88 (76%) of the 116 had complete resolution of their symptoms. Six patients (4%) without diplopia preoperatively were found to have this symptom postoperatively. CONCLUSIONS: The findings suggest that most visually mature patients under-going strabismus surgery can expect functional benefits, including improvement of alignment, preservation and occasionally restoration of sensory fusion, and elimination of diplopia, abnormal head posture and asthenopia.     

Chemically dependent doctors

Overcoming denial and admitting to having a chemical dependency problem is a hurdle that is extraordinarily difficult for anyone to handle without professional assistance. Addicted health care professionals often become even more deeply enmeshed in denial of their problem. They refuse help because they see themselves as educated beyond the level of those who are attempting to help them, and because they fear professional humiliation. Dental professionals who become aware of a colleague's chemical dependence, have an ethical duty to intervene in a constructive way. Reporting to a dental society wellness committee will accomplish this goal while protecting patients, the profession, the addicted provider, and the provider's family. Nonetheless, assisting chemically dependent colleagues to seek treatment can be an enormous burden. Thus, the dental hygienist in the case presented has few choices. She clearly has sufficient evidence of the dentist's chemical dependency problem and, ethically, she must act to prevent harm to patients. If a wellness program is available, it will help her. However, she should not expect gratitude from the dentist at the time of her intervention. Addicted persons rarely thank those who try to help them until much later and whistle-blowers are rarely appreciated. As is often the case, doing the right thing may be a challenge that risks losing a relationship or, as in the case presented, a job.     

Study of polymer electrolytes with grafted Au–γ-Fe2O3 nanoparticles

The work is aimed at enhancing the Li⁺ ion-conduction properties of polymer electrolytes (PE) for thin-film solid-state batteries. The research exploits novel ideas of structuring ionically conducting polymers or molecular polyether building blocks with grafted magnetic nanoparticles with the use of magnetic field, in order to enhance ionic conductivity along oriented helical PE chains. The experimental route being tested is based on the chemisorption of thiolated PEO on core–shell gold-coated maghemite. It was found that casting, under a gradient magnetic field (GMF), of concentrated PEs containing very small concentration – 0.5%(w/w) dithiol-connected Fe₂O₃/Fe₃O₄–Au nanoparticles results in enhancement of the total ionic conductivity by more than an order of magnitude.     

The Sleep Heart Health Study: design, rationale, and methods

The Sleep Heart Health Study (SHHS) is a prospective cohort study designed to investigate obstructive sleep apnea (OSA) and other sleep-disordered breathing (SDB) as risk factors for the development of cardiovascular disease. The study is designed to enroll 6,600 adult participants aged 40 years and older who will undergo a home polysomnogram to assess the presence of OSA and other SDB. Participants in SHHS have been recruited from cohort studies in progress. Therefore, SHHS adds the assessment of OSA to the protocols of these studies and will use already collected data on the principal risk factors for cardiovascular disease as well as follow-up and outcome information pertaining to cardiovascular disease. Parent cohort studies and recruitment targets for these cohorts are the following: Atherosclerosis Risk in Communities Study (1,750 participants), Cardiovascular Health Study (1,350 participants), Framingham Heart Study (1,000 participants), Strong Heart Study (600 participants), New York Hypertension Cohorts (1,000 participants), and Tucson Epidemiologic Study of Airways Obstructive Diseases and the Health and Environment Study (900 participants). As part of the parent study follow-up procedures, participants will be surveyed at periodic intervals for the incidence and recurrence of cardiovascular disease events. The study provides sufficient statistical power for assessing OSA and other SDB as risk factors for major cardiovascular events, including myocardial infarction and stroke.     

Dopamine D3 receptor mutant mice exhibit increased behavioral sensitivity to concurrent stimulation of D1 and D2 receptors

The dopamine D3 receptor is expressed primarily in regions of the brain that are thought to influence motivation and motor functions. To specify in vivo D3 receptor function, we generated mutant mice lacking this receptor. Our analysis indicates that in a novel environment, D3 mutant mice are transiently more active than wild-type mice, an effect not associated with anxiety state. Moreover, D3 mutant mice exhibit enhanced behavioral sensitivity to combined injections of D1 and D2 class receptor agonists, cocaine and amphetamine. However, the combined electrophysiological effects of the same D1 and D2 agonists on single neurons within the nucleus accumbens were not altered by the D3 receptor mutation. We conclude that one function of the D3 receptor is to modulate behaviors by inhibiting the cooperative effects of postsynaptic D1 and other D2 class receptors at systems level.     

Response map properties of units in the dorsal cochlear nucleus of barbiturate-anesthetized gerbil (Meriones unguiculatus)

The response map scheme introduced by Evans and Nelson (1973) and modified by others, including Davis et al. (1996) for use with gerbils, has been used primarily for classifying units recorded in the cochlear nucleus of unanesthetized decerebrate preparations. Units lacking spontaneous activity (SpAc) have been classified as either type I/III or type II units based on the relative strength of their responses to broad-band noise compared to their responses to best-frequency (BF) tones. The relative noise index (rho), a ratio of these responses after SpAc is subtracted out, provides a convenient measure of this relative strength. In this paper, responses of 320 units recorded in the dorsal cochlear nucleus (DCN) of barbiturate-anesthetized gerbils to short-duration BF tones and broad-band noise were recorded. Since 87.5% of these units lacked SpAc, their response maps resembled those of type II and type I/III units. Units were characterized by rho and the normalized slope (m) of a best line fit to the BF rate versus level plot starting from the sound level corresponding to the first inflection point of the rate curve (typically its maximum value or the start of its sloping saturation). The distributions of rho and m values do not form distinct clusters as they do for units in the decerebrate preparation. Thus, the criteria developed for classifying DCN units in the decerebrate preparation do not appear appropriate for units in the barbiturate-anesthetized preparation. Deposits of horseradish peroxidase were used to locate 52 units. Most of the low SpAc units, 56% with poor noise responses (5/9) and nearly 70% with strong noise responses (25/36), and nearly all of the high SpAc units (6/7), were located either within or below the fusiform cell layer.     

Kinetic and spectroscopic properties of the YZ* radical in Ca2+- and Cl--depleted photosystem II preparations

Depletion of Ca2+ and/or Cl- ions from PSII membranes blocks the electron-transfer reactions that precede O2 evolution on the oxidizing side of the enzyme. Illumination of these inhibited preparations at 273 K generates a paramagnetic species that is detectable by low-temperature (T < 20 K) EPR as a signal in the g = 2 region, 90-230 G wide, depending on the treatment that PSII has undergone. This signal has recently been assigned to YZ* in magnetic interaction with the manganese cluster in its S2 state [Gilchrist et al. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 9545-9549]. This view, however, is not universal, owing, in part, to the fact that its spectroscopic properties depend on the preparation and the experimental conditions used for its study and, in part, to uncertainties as to the room temperature behavior of YZ* in inhibited preparations. Here, we report time-resolved and conventional EPR data showing that, at room temperature and at 273 K, YZ* can be accumulated in its 20 G form in high yields in both Ca2+-depleted and acetate-inhibited preparations, and that the kinetics of its decay match the decay kinetics of the low-temperature signal generated in corresponding samples. The properties of the YZ* signal, however, are shown to depend on the polypeptide content, the temperature, and the electron donors and acceptors present in the sample under examination. Our results support assignment of the EPR signal in inhibited preparations to S2 YZ* and demonstrate a protective role of the 17 and 23 kDa extrinsic polypeptides for the manganese cluster against externally added reductants.     

Preservation of global cardiac function in the rabbit following protracted ischemia/reperfusion using monophosphoryl lipid A (MLA)

Monophosphoryl lipid A (MLA), a derivative of the minimal substructure of lipopolysaccharide (lipid A) possesses immunomodulatory activity of the parent lipid A yet enjoys reduced toxicity. It has previously been reported that pretreatment with MLA reduces myocardial infarct size and stunning in dogs following ischemia and reperfusion. The aim of this study was to evaluate the ability of monophosphoryl lipid A (MLA) to preserve global cardiac function and peripheral hemodynamics in a rabbit model of prolonged regional ischemia (90 min), and reperfusion (6 h). An evaluation of potential mechanisms by which MLA may preserve cardiac function was also undertaken. Single dose pretreatment with MLA (35 micrograms/kg i.v.) 24 h prior to ischemia resulted in significant improvement in left ventricular developed pressure, dP/dt, rate-pressure product and mean arterial pressure during reperfusion (P < 0.05 v control). Although in this model of prolonged ischemia MLA pretreatment did not reduce infarct size (54.5 +/- 11.4% in control v 63.3 +/- 8.3% in MLA, P = N.S.), evaluation of myocardial adenylate and adenosine catabolite pools at the end of ischemia indicated a preservation of ATP and ADP and a decreased production of downstream adenosine catabolites including inosine, xanthine and uric acid. Adenosine kinase, but not 5'-nucleotidase (5'-NTase) or adenosine deaminase activity determined following reperfusion was 76% and 60% higher (P < 0.05) in non-risk and post-ischemic myocardium of MLA pretreated rabbits compared with controls. Although there was a trend toward lower tissue myeloperoxidase activity in post-ischemic myocardium from treated rabbits, the results were not significantly different from control animals. These results suggest that a 24-h pretreatment with MLA, without further treatment during ischemia or reperfusion was associated with: (1) preservation of global myocardial function during reperfusion; (2) preservation of myocardial high energy adenylates and reduced formation of adenosine catabolites during ischemia; (3) elevated myocardial adenosine kinase activity. Increased recycling of adenosine to phosphorylated nucleotides may result from MLA's affect on adenosine kinase, which could explain the drugs effect on adenylate and adenosine metabolite pools.