The role of clinical parapapillary atrophy evaluation in the diagnosis of open angle glaucoma

Joshua R Ehrlich, Nathan M RadcliffeDepartment of Ophthalmology, Weill Cornell Medical College, New York, NY, USAPurpose: To determine if clinical evaluation of parapapillary atrophy (PPA) significantly improves the ability to distinguish open-angle glaucoma (OAG) patients from glaucoma suspects.Methods: Patients in this study were under evaluation for glaucoma and had open angles, at least one reliable 24-2 SITA-standard automatic perimetry, and digital stereophotographs of the optic disc. PPA was identified clinically as a parapapillary region of absent (βPPA) or hyper/hypopigmented (αPPA) retinal pigment epithelium. A single masked observer evaluated photos for: vertical cup-to-disc ratio (CDR), clock hours of total and βPPA, βPPA as percentage width of the optic disc, presence or absence of βPPA at each disc quadrant, and ordinal rating of total PPA. Generalized linear models were used to determine odds of an abnormal or borderline glaucoma hemifield test (GHT) as a function of PPA variables and covariates; model fit was assessed using the log-likelihood ratio test.Results: Of 410 consecutive patients, 540 eyes (of 294 patients) met inclusion criteria. Mean age was greater among patients with abnormal compared with normal GHT (P < 0.001), but sex and race/ethnicity did not differ between groups (P ≥ 0.22). Age, central corneal thickness (CCT) and CDR (P ≤ 0.006), but not intraocular pressure (IOP) (P = 0.71), were significant univariable predictors of the odds of an abnormal GHT. All PPA parameters significantly ­predicted GHT (P ≤ 0.03), except presence of temporal βPPA (P = 0.25). Adjustment for age, CCT, IOP, and CDR reduced the association between PPA and GHT, and model fit was not greatly improved by addition of PPA variables.Conclusions: Addition of most PPA parameters to a model already containing commonly assessed variables including age, CCT, IOP, and CDR does not significantly improve the ability to distinguish OAG patients from glaucoma suspects.Keywords: glaucoma, visual fields, parapapillary atrophy, optic nerv

Habitat conversion and global avian biodiversity loss

The magnitude of the impacts of human activities on global biodiversity has been documented at several organizational levels. However, although there have been numerous studies of the effects of local-scale changes in land use (e.g. logging) on the abundance of groups of organisms, broader continental or global-scale analyses addressing the same basic issues remain largely wanting. None the less, changing patterns of land use, associated with the appropriation of increasing proportions of net primary productivity by the human population, seem likely not simply to have reduced the diversity of life, but also to have reduced the carrying capacity of the environment in terms of the numbers of other organisms that it can sustain. Here, we estimate the size of the existing global breeding bird population, and then make a first approximation as to how much this has been modified as a consequence of land-use changes wrought by human activities. Summing numbers across different land-use classes gives a best current estimate of a global population of less than 100 billion breeding bird individuals. Applying the same methodology to estimates of original land-use distributions suggests that conservatively this may represent a loss of between a fifth and a quarter of pre-agricultural bird numbers. This loss is shared across a range of temperate and tropical land-use types

Functioning and Vision-Related Quality of Life in Severe Peripheral Field Loss due to Retinitis Pigmentosa: A Qualitative Study

Vision impairment and blindness are associated with disability and decreased social participation and independence. While vision rehabilitation may improve patients’ functional abilities, there is scarce data regarding the effectiveness of rehabilitation for patients with severe peripheral field loss (PFL). In order to evaluate rehabilitation strategies for individuals with severe PFL, a valid and reliable instrument to measure vision-dependent functioning and vision-related quality of life is needed. Accordingly, this qualitative study was the first phase in developing a patient-reported outcome (PRO) measure tailored to this population. Individuals with retinitis pigmentosa (RP) were recruited from the Kellogg Eye Center and the Association for the Blind and Visually Impaired. The study sample included 17 participants (53% female, mean age 48); median presenting visual acuity and Pelli-Robson contrast sensitivity were 20/40 and 1.2 log contrast sensitivity, respectively. The maximum horizontal extent of the Goldmann visual field was 11° in the better-seeing eye. Study participants completed a semi-structured qualitative interview, and two quality of life questionnaires. Interviews were recorded, transcribed and coded by two independent coders. Thematic analysis of the interview codes identified six vision-related quality of life themes across all RP participants: activity limitations, driving, emotional well-being, reading, mobility and social function. These themes will serve in the development of a PRO specific to severe PFL, which will facilitate evaluation and eventual evolution of low vision rehabilitation for patients with severe PFL

Modulation of Neuronal Signal Transduction Systems by Extracellular ATP

The secretion of ATP by stimulated nerves is well documented. Following repetitive stimulation, extracellular ATP at the synapse can accumulate to levels estimated to be well over 100 Μ M. The present study examined the effects of extracellular ATP in the concentration range of 0.1–1.0 m M on second-messenger-generating systems in cultured neural cells of the clones NG108-15 and NIE-115. Cells in a medium mimicking the physiological extracellular environment were used to measure 45 Ca 2+ uptake, changes in free intracellular Ca 2+ levels by the probes aequorin and Quin-2, de novo generation of cyclic GMP and cyclic AMP from intracellular GTP and ATP pools prelabeled with [ 3 H]guanosine and [ 3 H]adenine, respectively, and phosphoinositide metabolism in cells preloaded with [ 3 H]inositol and assayed in the presence of LiCI. Extracelluar ATP induced a concentration-dependent increase of 45 Ca 2+ uptake by intact cells, which was additive with the uptake induced by K + depolarization. The increased uptake involved elevation of intracellular free Ca 2+ ions, evidenced by measuring aequorin and Quin-2 signals. At the same concentration range (0.1–1.0 m M ), extracellular ATP induced an increase in [ 3 H]cyclic GMP formation, and a decrease in prostaglandin E 1 -stimulated [ 3 H]cyclic AMP generation. In addition, extracellular ATP (1 m M ) caused a large (15-fold) increase in [ 3 H]inositol phosphates accumulation, and this effect was blocked by including La 3+ ions in the assay medium. In parallel experiments, we found in NG 108–15 cells surface protein phosphorylation activity that had an apparent K m for extracellular ATP at the same concentration required to produce half-maximal effects on Ca 2+ uptake. Extracellular ATP at concentrations that can be produced in the synaptic cleft by repetitive stimulation but not during routine transmission can thus initiate a unique chain of events, which may play a role in the induction of long-term adaptive changes in neuronal function.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65952/1/j.1471-4159.1988.tb13263.x.pd

Bunge’s Mathematical Structuralism Is Not a Fiction

In this paper, I explore Bunge’s fictionism in philosophy of mathematics. After an overview of Bunge’s views, in particular his mathematical structuralism, I argue that the comparison between mathematical objects and fictions ultimately fails. I then sketch a different ontology for mathematics, based on Thomasson’s metaphysical work. I conclude that mathematics deserves its own ontology, and that, in the end, much work remains to be done to clarify the various forms of dependence that are involved in mathematical knowledge, in particular its dependence on mental/brain states and material objects

Solitonic-exchange mechanism of surface~diffusion

We study surface diffusion in the framework of a generalized Frenkel-Kontorova model with a nonconvex transverse degree of freedom. The model describes a lattice of atoms with a given concentration interacting by Morse-type forces, the lattice being subjected to a two-dimensional substrate potential which is periodic in one direction and nonconvex (Morse) in the transverse direction. The results are used to describe the complicated exchange-mediated diffusion mechanism recently observed in MD simulations [J.E. Black and Zeng-Ju Tian, Phys. Rev. Lett. {\bf 71}, 2445-2448(1993)].Comment: 22 Revtex pages, 9 figures to appear in Phys. Rev.

Underrecognition and undertreatment of asthma in Cape Town primary school children

Background. In view of the high local prevalence of asthma, the extent of recognition and appropriate managementof childhood asthma was studied in a large suburban area of Cape Town.Design. Cross-sectional study based on random community sample of schools.Method. 1955 parents of sub B pupils from 16 schools completed a questionnaire, followed by: (f) an interview of parents of 348 symptomatic children; and (if) bronchial responsiveness testing on 254 children. the final case group consisted of 242 children with reported asthma or multiple asthma symptoms on both questionnaires. Children in whom asthma was acknowledged were compared with those in whom it was not.Results. Overall, any past or current ('ever') asthma was acknowledged by respondents in only 53% of the children, and current asthma in only 37.1%. While most children had received treatment in the previous 12 months, 66.1% of therecognised group were on current treatment (23.2% on daily treatment), compared with 37% of the unrecognised group (3% daily). Salbutamol and theophylline syrups were the most common types of medication, while inhalers and antiinflammatory medications were underused. Only a minority of parents reported the child ever having used a peak flow meter, or volunteered knowledge of preventive measures. Current treatment, and to a lesser degree recognition of asthma by parents, were more common among children on medical aid and of higher socio-eonomic status.Conclusions. These findings suggest that ways need to be found: (i) to increase the use of current asthma treatment guidelines by practitioners; (ii) to provide access to comprehensive care by children not on medical aid; and (iii) to improve education of parents in home management measures such as severity assessment and avoidance of smoking, allergen and dietary triggers