Prevalence of visual impairment, cataract surgery and awareness of cataract and glaucoma in Bhaktapur district of Nepal: The Bhaktapur Glaucoma Study

Background

The present study investigates two different treatment options for convergence insufficiency CI for a group of children with reading difficulties referred by educational institutes to a specialist eye clinic in Vienna.

Methods

One hundred and thirty four subjects (aged 7-14 years) with reading difficulties were referred from an educational institute in Vienna, Austria for visual assessment. Each child was given either 8Δ base-in reading spectacles (n = 51) or computerised home vision therapy (HTS) (n = 51). Thirty two participants refused all treatment offered (clinical control group). A full visual assessment including reading speed and accuracy were conducted pre- and post-treatment.

Results

Factorial analyses demonstrated statistically significant changes between results obtained for visits 1 and 2 for total reading time, reading error score, amplitude of accommodation and binocular accommodative facility (within subjects effects) (p < 0.05). Significant differences were also demonstrated between treatment groups for total reading time, reading error score and binocular accommodative facility (between subjects effects) (p < 0.05).

Conclusions

Reading difficulties with no apparent intellectual or psychological foundation may be due to a binocular vision anomaly such as convergence insufficiency. Both the HTS and prismatic correction are highly effective treatment options for convergence insufficiency. Prismatic correction can be considered an effective alternative to HTS.     

The visual claustrum of the cat. III. Receptive field properties

The visual response properties of cells in the cat's dorsocaudal claustrum were studied physiologically. Quantitative observations were made of 55 cells, and qualitative observations were made on 228 others. The claustral cells formed a physiologically homogeneous population. The overwhelming majority were orientation selective, and most also showed a striking preference for long stimuli, their responses summating up to lengths of 40 degrees or more. Moving stimuli were always much more effective than stationary ones. In other respects, claustral cells were tolerant of wide variation in stimulus features. Their responses were about equally brisk to either direction of movement of a properly oriented stimulus, and the velocity of movement was likewise not critical. They appeared not to summate across the dimension of their receptive fields orthogonal to the preferred orientation so that narrow or broad slits, or edges, evoked similar responses. Dark slits on light backgrounds were as effective as light slits on dark backgrounds. Finally, a large majority of cells were driven equally well by either eye. These properties of claustral cells differ in several respects from those of their principal targets, cells in layer IV of visual cortex.     

The visual claustrum of the cat. II. The visual field map

Physiological and anatomical methods were used to study the representation of the visual field in the cat's dorsocaudal claustrum. In one set of experiments, the visual receptive fields of claustral neurons were plotted in multiple electrode penetrations. In another set of experiments, the termination of the corticoclaustral pathway was examined autoradiographically after the injection of [3H]proline at retinotopically defined sites in the visual cortex. Results obtained by the two methods were in close agreement. The claustrum was found to contain a single, orderly map of the contralateral hemifield and a small part of the ipsilateral field. High elevations are represented caudally and ventrally, low elevations rostrally and dorsally. The surface of the claustrum represents the periphery of the visual field, while the vertical meridian lies more ventrally, where the visual claustrum abuts the non-visual part of the nucleus. Visual field lines (isoazimuths or isoelevations) are represented as planes in the claustrum. The map is unusual in that isoazimuth planes are strongly curved and nested within each other, with peripheral ones enclosing those closer to the vertical meridian. This arrangement permits an expanded representation of the periphery compared with what is seen in visual cortex. The inputs from areas 17, 18, 19, 21a, and PMLS (posteromedial lateral suprasylvian area) are convergent, each projection retinotopically to the entirety of the claustral map.     

Accurate visual guidance despite severe neglect

Unilateral inactivation of the superior colliculus causes profound neglect. In cats, this neglect has been studied previously using tasks that require gaze orientation to, or detection of, a stimulus appearing somewhere in the visual field of an attentive animal. We investigated how neglect affects a completely different kind of task, visually guided foot placement while walking across a cluttered surface. We made muscimol injections into one superior colliculus, and performed perimetry to gauge the extent of the cat's neglect. Cats then walked repeatedly through a cluttered test alley. Most of the time, their gaze was deviated towards the side of the injection, so that they saw the alley floor ahead of them in their neglected hemifield. Surprisingly, they accurately avoided stepping on the densely scattered objects, just as they normally do. We surmise that cats process 'neglected' visual stimuli to guide foot placement even when they are unable to consciously perceive these stimuli.     

Contamination of operating room personnel during total arthroplasty

The authors prospectively evaluated the degree of contamination to the operating room team during 60 consecutive total joint arthroplasties. Each member of the team was required to wear a hood, mask, protective eyewear, and shoecovers. At the conclusion of each procedure, all members were assessed in terms of degree and location of contamination. One hundred percent of the surgeons and first assistants were exposed. The face and eyewear were noted to be the area of greatest contamination. The authors found orthopedic surgeons to be at significant risk of contamination with blood and body fluids during total joint arthroplasty.     

Flattening the cerebral cortex by computer.

A computer program was developed for unfolding the cerebral cortex so that it could be viewed as a 2-dimensional surface. Input to the program consisted of tissue sections cut in a standard plane of section. Each section was represented by one line, which corresponded to a contour line in the flattened map. From these data, the computer constructed a 3-dimensional surface representation, which it then flattened. Because the cerebral cortex has considerable intrinsic curvature, flattening required that some regions be expanded and others shrunken. These changes occurred as a natural consequence of local decisions made by the computer as it laid down successive contours. The user could intervene during both surfacing and flattening in order to shape the developing map. The program has been used to generate 37 flattened maps from various regions of cat cortex, and 1 from monkey cortex. The local topography of cortical features such as gyri, sulci, architectonic boundaries, and patches of transported tracer, appeared to be conserved fairly faithfully. Areal distortion was also modest, with an average change in surface area of only 12%.     

Health care services utilization stratified by virological and immunological markers of HIV: evidence from a universal health care setting

Objective

The aim of the study was to determine rates of utilization of in‐patient, out‐patient and laboratory services stratified by virological and immunological markers of HIV disease among patients on antiretroviral treatment in British Columbia, Canada.

Methods

We estimated resource utilization for in‐patient visits, out‐patient visits, and laboratory tests among patients initiating antiretroviral treatment between 1 April 1994 and 31 December 2000, with follow‐up to 31 March 2001. Resource use was stratified by CD4 cell count and plasma HIV viral load (pVL) at the time of utilization and rates per 100 patient‐years were calculated for each health care resource.

Results

A total of 2718 patients were included in our analyses. The overall rates of in‐patient visits, out‐patient visits, and laboratory tests were 902, 3001 and 840 per 100 patient‐years, respectively. Utilization was higher for patients with low CD4 cell counts and high pVLs when compared with patients with high CD4 cell counts and low pVLs.

Conclusions

Patients with low CD4 cell counts and high pVLs had the highest use of health care services. Regular follow‐up with health care providers in an out‐patient setting, allowing for proper monitoring and maintenance of HIV care, is important in minimizing unnecessary and potentially costly in‐patient care.     

Local delivery of sirolimus nanoparticles for the treatment of in‐stent restenosis

Transcatheter aortic valve implantation is a possible, although off‐label, alternative to conventional aortic valve replacement for high‐surgical‐risk patients with severe, non‐calcified aortic regurgitation (AR). To date, feasibility has only been demonstrated with the Medtronic CoreValve prosthesis (MCV). This prosthesis needs the aortic sinuses to have enough width to avoid coronary obstruction. We report a case of MCV implantation for severe AR where the narrow aortic root theoretically precluded the technique. Good procedural outcome was achieved thanks to a strategy of implantation with planned positioning of the prosthesis leaflets away from the coronary arteries. © 2013 Wiley Periodicals, Inc.     

Synthesis and biological evaluation of 1-aryl-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-one inhibitors of cyclin-dependent kinases

Using a high-throughput screening strategy, a series of 1-aryl-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-ones was identified that inhibit the cyclin-dependent kinase (CDK) 4/cyclin D1 complex-mediated phosphorylation of a protein substrate with IC(50)s in the low micromolar range. On the basis of preliminary structure-activity relationships (SAR), a model was proposed in which these inhibitors occupy the ATP-binding site of the enzyme, forming critical hydrogen bonds to the same residue (Val96) to which the amino group in ATP is presumed to bind. X-ray diffraction studies on a later derivative bound to CDK2 support this binding mode. Iterative cycles of synthesis and screening lead to a novel series of potent, CDK2-selective 6-(arylmethyl)pyrazolopyrimidinones. Placement of a hydrogen-bond donor in the meta-position on the 6-arylmethyl group resulted in approximately 100-fold increases in CDK4 affinity, giving ligands that were equipotent inhibitors of CDK4 and CDK2. These compounds exhibit antiproliferative effects in the NCI HCT116 and other cell lines. The potency of these antiproliferative effects is enhanced in anilide derivatives and translates into tumor growth inhibition in a mouse xenograft model.