Use of pupil size and reaction to detect orbital trauma during and after surgery

We describe how pupillary reactions, used as an index of optic nerve function, can be elicited using only one working pupil. This is to challenge the conclusion of a study that did not appreciate this physiological phenomenon and thus gave rise to erroneous conclusions that might otherwise limit the scope of pupil measurements during and after surgery. For suitable cases, non-opioid anaesthesia and further clinical development of pupillometry are suggested by us as measures to monitor optic nerve function.     

Molecular and clinical epidemiology of vancomycin-resistant Enterococcus faecalis

OBJECTIVES: With the recent emergence of vancomycin-resistant (VR) Staphylococcus aureus, subsequent to the suggested transfer of the vanA resistance gene from Enterococcus faecalis, we sought to determine risk factors for acquisition of VR E. faecalis and to evaluate the molecular epidemiology of this less-prevalent and less-studied species of VR enterococcus. METHODS: We compared clinical isolates of VR E. faecalis from 71 patients, collected over 12 years in a large community teaching hospital, with isolates from 126 patients with vancomycin-susceptible E. faecalis. RESULTS: Risk factors for VR E. faecalis acquisition by multivariate analysis were nursing home residence (P = 0.0005), haemodialysis (P = 0.009), decubitus ulcers (P = 0.03) and receipt of parenteral vancomycin (P = 0.0002). Twenty-one percent of VR E. faecalis demonstrated vanA and 79% vanB resistance. The number of VanA isolates increased over time. Molecular analysis showed vanA or vanB in multiple PFGE groups. CONCLUSIONS: The results of this study suggest gene dissemination among some isolates and intra-hospital spread of other isolates. The risk factors identified clearly suggest that VR E. faecalis is a nosocomial pathogen and should be considered in infection control practices. Further surveillance of VR E. faecalis is warranted, due to the potential spread of vancomycin resistance among enterococci and staphylococci.     

Percutaneous nephrolithotomy in children before school age: experience of a Pakistani centre

OBJECTIVE: To review our experience of percutaneous nephrolithotomy (PCNL) in children before school age, and determine its efficacy and safety in this age group. PATIENTS AND METHODS: The records of children aged < or = 5 years undergoing PCNL were reviewed. Variables assessed included stone number, size, location and type. The PCNL puncture site and number were also recorded. We reviewed stone clearance with PCNL, ancillary procedures used, complication rates and follow-up status of the children. RESULTS: There were 30 renal units in 29 children (median age 3.8 years, range 1.4-5). Because of poor growth the mean (SD) body weight of the children was only 12.2 (2.8) kg, which is near the 50th percentile for children of mean age 3.5 years. The median (range) stone burden was 2.35 (1.3-6) cm; 60% of the patients had single stones while 28% had more than five. There were five staghorn stones. All PCNL was primary and with one puncture, using a 17 F angled nephroscope; stones were fragmented using a pneumatic lithoclast. After PCNL stones were completely cleared in 60% of the renal units, which increased to 100% after combining it with extracorporeal shockwave lithotripsy. The median (range) follow-up was 24.9 (4-51) months; the overall complication rate was 6%. In the long follow-up hypertension was not detected in any child and isotopic renograms in 17 kidneys detected no new scarring or loss of renal function. CONCLUSION: PCNL is a safe and effective for treating renal stones in very young children.     

Criteria for improving visual acuity in ischaemic branch retinal vein occlusion using argon laser

PURPOSE: To re-assess the value of argon laser treatment for macular oedema in ischaemic branch retinal vein occlusion (I-BRVO). METHODS: Case series consisting of three patients with macular oedema following I-BRVO. Three patients were studied including two patients where ischaemia extended to include the foveal avascular zone (FAZ), with additional retinal neovascularisation in one of these. Heavy, overlapping areas of treatment were applied to the ischaemic retina up to 500 microns from the fovea. RESULTS: All cases in the series benefited from significantly improved visual acuity. In one case laser was given several years after the initial retinal vasculopathy. CONCLUSIONS: Argon laser treatment may improve visual acuity in I-BRVO even with severe ischaemia extending into the FAZ. Treatment intensity must be sufficient to destroy ischaemic retina. Visual benefit may last for several years, and treatment can be undertaken several years after I-BRVO. The benefit to visual acuity of argon laser treatment in I-BRVO needs to be re-assessed in a prospective study.     

Three-dimensional shape from non-homogeneous textures: carved and stretched surfaces

We examined the perception of 3D shape for surfaces folded, carved, or stretched out of textured materials. The textures were composed of sums of sinusoidal gratings or of circular dots, and were designed to differentiate between orientation and frequency information present in perspective images of the surfaces. Correct perception of concavities, convexities, saddles, and slants required the visibility of signature patterns of orientation modulations. These patterns were identical to those identified previously for developable surfaces (A. Li & Q. Zaidi, 2000; Q. Zaidi & L. Li, 2002), despite the fact that textures were statistically homogeneous on developable surfaces but not on carved or stretched surfaces. Frequency modulations in the image were interpreted as cues to distance from the observer, which led to weak but qualitatively correct percepts for some carved and stretched surfaces but to misperceptions for others, similar to the misperceptions for developable surfaces (A. Li & Q. Zaidi, 2003). Irrespective of whether texture on the surface is homogeneous or non-homogeneous, similar neural modules can be used to locate signature orientation modulations and thus extract shape from texture cues.     

Illuminant color perception of spectrally filtered spotlights

The color perceived to belong to the illumination of objects is often based on cues from the scene within which the objects are perceived, instead of being based on any view of the source itself. We present measurements of illuminant color estimation by human observers for moving, spectrally filtered spotlights. The results show that when only one illuminant is in the field of view, estimates of illuminant color are seriously biased by the chromaticities of the illuminated surfaces. When the surround of the spotlight is illuminated by a dimmer second light, spotlight matching moves toward veridical in most conditions. Simulations show that a gray-world model cannot be rejected as an adequate explanation for illuminant color estimation and provides as good a fit as a model that gives greater weights to the brightest surfaces. When the surrounding illuminant is brighter than the spotlight, the situation is similar to that of a moving filter. Spotlight matches are close to veridical, and the results can be fit by a model based on estimating both illuminants.     

Runx2 control of organization, assembly and activity of the regulatory machinery for skeletal gene expression

We present an overview of Runx involvement in regulatory mechanisms that are requisite for fidelity of bone cell growth and differentiation, as well as for skeletal homeostasis and the structural and functional integrity of skeletal tissue. Runx-mediated control is addressed from the perspective of support for biological parameters of skeletal gene expression. We review recent findings that are consistent with an active role for Runx proteins as scaffolds for integration, organization and combinatorial assembly of nucleic acids and regulatory factors within the three-dimensional context of nuclear architecture.     

New oligodendrocytes are generated after neonatal hypoxic-ischemic brain injury in rodents

Neonatal hypoxic-ischemic (HI) white matter injury is a major contributor to chronic neurological dysfunction. Immature oligodendrocytes (OLGs) are highly vulnerable to HI injury. As little is known about in vivo OLG repair mechanisms in neonates, we studied whether new OLGs are generated after HI injury in P7 rats. Rats received daily BrdU injections at P12-14 or P21-22 and sacrificed at P14 to study the level of cell proliferation or at P35 to permit dividing OLG precursors to differentiate. In P14 HI-injured animals, the number of BrdU+ cells in the injured hemisphere is consistently greater than controls. At P35, sections were double-labeled for BrdU and markers for OLGs, astrocytes, and microglia. Double-labeled BrdU+/myelin basic protein+ and BrdU+/carbonic anhydrase+ OLGs are abundant in the injured striatum, corpus callosum, and the infarct core. Quantitative studies show four times as many OLGs are generated from P21-35 in HI corpora callosa than controls. Surprisingly, the infarct core contains many newly generated OLGs in addition to hypertrophied astrocytes and activated microglia. These glia and non-CNS cells may stimulate OLG progenitor proliferation or induce their migration. At P35, astrogliosis and microgliosis are dramatic ipsilaterally but only a few microglia and some astrocytes are BrdU+. This finding indicates microglial and astrocytic hyperplasia occurs shortly after HI but before the P21 BrdU injections. Although the neonatal brain undergoes massive cell death and atrophy the first week after injury, it retains the potential to generate new OLGs up to 4 weeks after injury within and surrounding the infarct.     

Successful treatment of systemic and central nervous system lymphomatoid granulomatosis with rituximab

Lymphomatoid granulomatosis (LYG) is a rare lymphoproliferative disorder with a mortality rate approaching 60% in the first year. The median survival is 14 months from the time of diagnosis. Although a variety of chemotherapeutic regimens have been utilized, there is no standard treatment. Studies have shown that in most cases the malignant cells are B-cells, which induce massive infiltration of reactive T-lymphocytes in the background. The disease is therefore considered as a T-cell rich B-cell lymphoproliferative disorder. We report a case of LYG with pulmonary, hepatic, central and peripheral nervous system involvement that was successfully treated with the anti-CD20 (B-cell) monoclonal antibody, Rituximab.