Hippocampal pathology in refractory temporal lobe epilepsy: T2-weighted signal change reflects dentate gliosis.

BACKGROUND: The MR and pathologic features of hippocampal sclerosis (HS) are well described and include volume decrease and T2-weighted signal increase for MRI, and neuron cell loss and gliosis for pathology. OBJECTIVE: To confirm the established correlation between hippocampal volumes and neuron cell counts, and to study the still controversial association between signal change and gliosis. METHODS: The authors studied 44 patients (22 men and 22 women; mean age at surgery, 37 years) with refractory temporal lobe epilepsy. Quantitative assessment of hippocampal volumes and T2 relaxometry, and neuron and glial cell count in the region CA1 and molecular layer of the dentate gyrus was performed. The proportion of glial fibrillary acidic protein (GFAP)-positive glial cells (reactive astrocytes) was indicated. RESULTS: In a stepwise regression, the ipsilateral hippocampal volume was predicted best by the neuron cell count in the dentate gyrus (p = 0.005, r = 0.4). Hippocampal T2 time, however, was predicted best by the glial cell count in the dentate gyrus (p = 0.01, r = 0.4). None of the other cell counts contributed to either model. In the dentate, 31% of the glial cells were reactive astrocytes, whereas in CA1, 5% were reactive. CONCLUSION: The results confirmed the correlation between hippocampal volumes and neuron cell counts. T2-weighted signal increase in the hippocampus was mainly influenced by gliosis in the dentate gyrus, where a high proportion of glial cells show abnormal activity. This activity may reflect changes important in the development of hippocampal epileptogenicity.     

Histopathological features of congenital fundus lesions in familial adenomatous polyposis

We report the light and electron microscopic findings for two lesions from two patients who died of complications of familial adenomatous polyposis. In the first case microscopy of a small (100 to 200 mu), uniformly dark lesion (the commonest type seen in this condition) showed enlarged retinal pigment epithelial cells with an increased number of pigment granules. This is consistent with the term "hypertrophy of the retinal pigment epithelium", currently used to describe these lesions. In the second case we sectioned a larger (1000 to 1500 mu), oval, grey lesion from the posterior pole. The pigment epithelium was normal, but between it and outer retina was an unusual choristoma consisting largely of myelinated axons and astrocytes.     

Glomus vagale presenting as a supraclavicular mass: Magnetic resonance imaging findings

Glomus vagale are rare vascular tumours of the paraganglion cells of the vagus nerve, and they usually occur in the carotid space. Tumours can be familial, multicentric, malignant but rarely hormonally active. A rare case is reported of glomus vagale presenting as a supraclavicular mass.     

SDF‐1/CXCR4/CXCR7 is pivotal for vascular smooth muscle cell proliferation and chronic allograft vasculopathy

Chronic rejection remains a major obstacle in transplant medicine. Recent studies suggest a crucial role of the chemokine SDF‐1 on neointima formation after injury. Here, we investigate the potential therapeutic effect of inhibiting the SDF‐1/CXCR4/CXCR7 axis with an anti‐SDF‐1 Spiegelmer (NOX‐A12) on the development of chronic allograft vasculopathy. Heterotopic heart transplants from H‐2bm12 to B6 mice and aortic transplants from Balb/c to B6 were performed. Mice were treated with NOX‐A12. Control animals received a nonfunctional Spiegelmer (revNOX‐A12). Samples were retrieved at different time points and analysed by histology, RT‐PCR and proliferation assay. Blockade of SDF‐1 caused a significant decrease in neointima formation as measured by intima/media ratio (1.0 ± 0.1 vs. 1.8 ± 0.1, P < 0.001 AoTx; 0.35 ± 0.05 vs. 1.13 ± 0.27, P < 0.05 HTx). In vitro treatment of primary vascular smooth muscle cells with NOX‐A12 showed a significant reduction in proliferation (0.42 ± 0.04 vs. 0.24 ± 0.03, P < 0.05). TGF‐β, TNF‐α and IL‐6 levels were significantly reduced under SDF‐1 inhibition (3.42 ± 0.37 vs. 1.67 ± 0.33, P < 0.05; 2.18 ± 0.37 vs. 1.0 ± 0.39, P < 0.05; 2.18 ± 0.26 vs. 1.6 ± 0.1, P < 0.05). SDF‐1/CXCR4/CXCR7 plays a critical role in the development of chronic allograft vasculopathy (CAV). Therefore, pharmacological inhibition of SDF‐1 with NOX‐A12 may represent a therapeutic option to ameliorate chronic rejection changes.     

Modeling the Nonlinear Deformation of Highly Porous Cellular Plastics Filled with Clay Nanoplatelets

Rigid low-density plastic foams subjected to mechanical loads typically exhibit a nonlinear deformation stage preceding failure. At moderate strains, when the geometrical nonlinearity is negligible, such foam response is predominantly caused by the nonlinearity of deformation of their principal structural elements—foam struts. Orientational averaging of stresses in foam struts enables estimation of the stresses taken up by foams at a given applied strain. Based on a structural model of highly porous anisotropic cellular plastics filled with clay nanoplatelets and the orientational averaging, a method for calculating their nonlinear deformation is derived in terms of structural parameters of the porous material, the mechanical properties of the monolithic polymer, and filler particles and their spatial orientation. The method is applied to predicting the tensile stress-strain diagrams of organoclay-filled low-density rigid polyurethane foams, and reasonable agreement with experimental data is demonstrated.     

Obtaining lignocellulosic biomass-based catalysts and their catalytic activity in cellobiose hydrolysis and acetic acid esterification reactions

Global challenges prompt the world to modify its strategies and shift from a fossil-fuel-based economy to a bio-resource-based one with the production of renewable biomass chemicals. Different processes exist that allow the transformation of raw biomass into desirable bio-based products and/or energy. In this work different biochars that were obtained as a by-product from birch chip fast pyrolysis and carbonization were used as is or chemically/physically treated. These sulfonated carbon catalysts were compared to a commercially available sulfonated styrene-divinylbenzene macroreticular resin (Dowex 50W X8). Characterisation (water content and pH value, FTIR, base titration, element analysis and N₂ desorption) was done to evaluate the obtained sulfonated biocarbon catalysts. Catalytic activity was tested using cellobiose (CB) hydrolysis and acetic acid esterification. For the catalytic CB hydrolysis, we tested the reaction temperature, time and CB and catalyst mass ratios. The determined optimal conditions were 120 °C and 24 h, with CB and catalyst mass ratio 1 : 5. The highest glucose yield was observed for biochar obtained from the birch chip fast pyrolysis process (BC_Py-H₂SO₄) – 92% within 24 h for 120 °C. Comparably high glucose yield was observed for biochar that was obtained in birch chip carbonization (BC_Carbon-H₂SO₄) – 86% within 24 h for 120 °C.

In this work different biochars that were obtained as a by-product from birch chip fast pyrolysis and carbonization were used as is or chemically/physically treated. The characterisation was done using CB hydrolysis and acetic acid esterification.     

Children's perceptions of strategies for resolving community health problems

We examine children's perceptions of the strategies they would use to resolve community health problems. Qualitative analysis using a grounded theory approach showed that 9- to 10-year-old children could conceptualize a range of solutions to hypothetical community health problems. Children's responses reflected an egocentric perspective, one that was centered on self and peers acting on short-term solutions to the immediate problem. Less frequently, children conceptualized broader structural interventions aimed at removing the problem altogether. Children could name resource persons including their friends, family, school personnel and other people in the community. However, outside of their family and peers, their knowledge was non-specific, i.e. it is doubtful that they would actually be able to access the resources. In light of our findings we discuss several important implications for future research. We note that children are interested in changing community conditions that affect their heath. However, their recognition of their marginalized position in adult society and their perception that adults do not take them seriously may be significant barriers to their participation. We suggest that society must rethink the position and roles that are assigned to children so that their valuable potential is not lost.     

Coventry Award paper. Backsurface wear and deformation in polyethylene tibial inserts retrieved postmortem

Wear and deformation were characterized at the backsurface of 25 posterior cruciate-retaining total knee arthroplasty polyethylene inserts retrieved postmortem from 20 subjects. The mean implantation time was 64.1 months (range, 4-156 months). The backsurface of the inserts was inspected using a stereomicroscope with a digital optical system. Coronal histologic sections of 13 proximal tibias were inspected for the presence and extent of penetration of granuloma. Damage to the backsurface was limited. Polishing was recorded on 21 (84%) of the inserts and abrasive wear on five (20%) inserts. Pitting was present in 21 (84%) components, but involved less than 1% of the area in all but one of these components. Delamination and cracking were not observed. Extrusions were seen in all 10 of the components that had screw holes in the tibial tray. A correlation was found between the depth of penetration of the granuloma along the posteromedial screw and the height of the corresponding extrusion. The anteroposterior profiles showed a concave deformation of the backsurface in 24 (96 %) of the cases. The concave deformation of tibial inserts may facilitate accumulation and transportation of wear debris to the tibial bone-implant interface through the screw holes in implants designed for cementless fixation.     

Stem curvature and load angle influence the initial relative bone-implant motion of cementless femoral stems

A 6 df measurement system was used to investigate the initial relative bone-implant motion of two types of cementless total hip replacement femoral components—a straight stem and a curved stem. Five pairs of fresh frozen femurs from human cadavers were tested with loads applied to the femoral head at angles characteristic of level walking, stair-climbing, and rising from a chair. The most important findings were that (a) the resultant proximal translations were twice as high with the straight stem as with the curved stem at load angles encountered in stair-climbing and rising from a chair, (b) both stem types had more motion at load angles encountered in stair-climbing and rising from a chair than in level walking, with the increases ranging from 3 to 14-fold, (c) there was as much as 66-fold more motion distally than proximally, and (d) the amount of interface motion varied by 5-fold between the medial and lateral surfaces of the distal part of the implant because of the combined effects of translation and rotation. The amount of initial bone-implant motion of the femoral component was found to be particularly sensitive to off-axis loading; this suggests that stair-climbing and rising from a chair should be avoided in the early postoperative period when a cementless porous-coated femoral stem has been used.     

Hemicranial Volume Deficits in Patients with Temporal Lobe Epilepsy With and Without Hippocampal Sclerosis

Summary: Purpose: In patients with refractory temporal lobe epilepsy, studies have suggested volume deficits measured by MRI of brain structures outside the epileptogenic hippocampus. Hippocampal sclerosis (HS) is a frequent, but not obligate, finding in such patients. The present study examines the influence of the presence of HS on quantitative magnetic resonance imaging (MRI) measurements.
Methods: We analyzed 47 patients and 30 controls by quantitative MRI, including intracranial volume (ICV), hemicranial volume, hippocampal volume (HCV), and T₂relaxometry. MRI results were compared with histological findings in the resected temporal lobe.
Results: Histology documented HS in 35 patients (HS group) and other findings in 12 patients (no-HS group). In both groups, the hemicranial volume ipsilateral to the epileptogenic focus was significantly smaller than on the contralateral side (p <0.004). The HCV on both sides was smaller in the HS group compared with patients without HS (p ≥ 0.004). Unilateral hippocampal atrophy and increased T, value were found in 71% of patients with HS, and bilaterally normal HCV and T, value were found in 67% of patients without HS.
Conclusions: The smaller hemicranial volume on the focus side, irrespective of the presence or absence of HS suggests a different pathogenic mechanism for the additional hemicranial volume deficit, compared to HS itself. The contralateral HCV deficit depends on the presence of HS, indicating a pathogenic connection between damage to both hippocampi.