Scleral thickness in highly myopic eyes measured by enhanced depth imaging optical coherence tomography

PURPOSE

The purpose of this study was to determine the subfoveal scleral thickness in highly myopic eyes by enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT) and to identify the ocular parameters significantly associated with the scleral thickness.

METHODS

The subfoveal scleral thickness of myopic eyes (≥-8 diopters (D) or axial length ≥26.5 mm) was examined by EDI-OCT. The correlations between the thickness and the best-corrected visual acuity (BCVA), refractive error, axial length (AL), the subfoveal retinal thickness, choroidal thickness, and posterior staphyloma height 2 mm from the fovea were investigated.

RESULTS

A total of 75 eyes of 54 patients (21 men, 33 women; mean age, 62.3±11.3 years; mean AL, 30.2±1.68 mm) were studied. Eighteen eyes had no pathological retinochoroidal lesions, and 57 eyes had retinochoroidal lesion, that is, myopic schisis, choroidal neovascularization, and other retinochoroidal pathologies. The mean subfoveal scleral thickness was 284.0±70.4 μm, and the thickness was significantly correlated negatively with the absolute value of the nasal and overall average posterior staphyloma height (P<0.05 and P<0.01, respectively). The subfoveal scleral thickness was also significantly correlated negatively with the relative value of the superior, nasal, and overall average posterior staphyloma height (P<0.05, P<0.01, and P<0.001, respectively). Stepwise analyses showed that the factor most significantly associated with the scleral thickness was the average relative posterior staphyloma height (F=16.0, P<0.001). The scleral thickness was not significantly different between eyes with and without myopic retinochoroidal pathologies (P>0.05).

CONCLUSION

Posterior staphyloma formation was a key factor associated with a posterior scleral thinning in highly myopic eyes.

Postoperative transient reduced diffusion in the ipsilateral striatum and thalamus

BACKGROUND AND PURPOSE

Restriction of diffusion has been reported in the early phase of secondary neuronal degeneration, such as wallerian degeneration. The purpose of this study was to investigate postoperative transient reduced diffusion in the ipsilateral striatum and thalamus as a remote effect of surgery.

MATERIALS AND METHODS

Six hundred two postoperative MR imaging examinations in 125 patients after cerebral surgery were retrospectively reviewed, focusing on the presence of reduced diffusion in the striatum and/or thalamus. The distribution of reduced diffusion in the striatum was classified into 3 groups: anterior, central, and posterior. Reduced diffusion in the thalamus was also classified on the basis of the anatomic locations of the thalamic nuclei. Further follow-up MRI was available in all patients with postoperative reduced diffusion, and acute infarctions were excluded. The patient medical records were reviewed to evaluate neurologic status.

RESULTS

Restriction of diffusion was observed in the striatum and/or thalamus ipsilateral to the surgical site in 17 patients (13.6%). The distribution of signal abnormality correlated with the location of the operation, in concordance with the architecture of the striatocortical and thalamocortical connections. Reduced diffusion was observed from days 7 to 46 after the operation, especially during days 8-21. The signal abnormalities completely resolved on follow-up examinations. The median follow-up period was 202 days (interquartile range, 76-487 days).

CONCLUSIONS

Postoperative transient reduced diffusion in the ipsilateral striatum and/or thalamus likely represents an early phase of secondary neuronal degeneration based on its characteristic distribution and time course. Clinically, this reduced diffusion should not be mistaken for postoperative ischemic injury.

Cortactin, an actin binding protein, regulates GLUT4 translocation via actin filament remodeling

Insulin regulates glucose uptake into fat and skeletal muscle cells by modulating the translocation of GLUT4 between the cell surface and interior. We investigated a role for cortactin, a cortical actin binding protein, in the actin filament organization and translocation of GLUT4 in Chinese hamster ovary (CHO-GLUT4myc) and L6-GLUT4myc myotube cells. Overexpression of wild-type cortactin enhanced insulin-stimulated GLUT4myc translocation but did not alter actin fiber formation. Conversely, cortactin mutants lacking the Src homology 3 (SH3) domain inhibited insulin-stimulated formation of actin stress fibers and GLUT4 translocation similar to the actin depolymerizing agent cytochalasin D. Wortmannin, genistein, and a PP1 analog completely blocked insulin-induced Akt phosphorylation, formation of actin stress fibers, and GLUT4 translocation indicating the involvement of both PI3-K/Akt and the Src family of kinases. The effect of these inhibitors was even more pronounced in the presence of overexpressed cortactin suggesting that the same pathways are involved. Knockdown of cortactin by siRNA did not inhibit insulin-induced Akt phosphorylation but completely inhibited actin stress fiber formation and glucose uptake. These results suggest that the actin binding protein cortactin is required for actin stress fiber formation in muscle cells and that this process is absolutely required for translocation of GLUT4-containing vesicles to the plasma membrane.

The 5'-flanking region of the RP58 coding sequence shows prominent promoter activity in multipolar cells in the subventricular zone during corticogenesis

Pyramidal neurons of the neocortex are produced from progenitor cells located in the neocortical ventricular zone (VZ) and subventricular zone (SVZ) during embryogenesis. RP58 is a transcriptional repressor that is strongly expressed in the developing brain and plays an essential role in corticogenesis. The expression of RP58 is strictly regulated in a time-dependent and spatially restricted manner. It is maximally expressed in E15-16 embryonic cerebral cortex, localized specifically to the cortical plate and SVZ of the neocortex, hippocampus, and parts of amygdala during brain development, and found in glutamatergic but not GABAergic neurons. Identification of the promoter activity underlying specific expression patterns provides important clues to their mechanisms of action. Here, we show that the RP58 gene promoter is activated prominently in multipolar migrating cells, the first in vivo analysis of RP58 promoter activity in the brain. The 5.3 kb 5'-flanking genomic DNA of the RP58 coding region demonstrates promoter activity in neurons both in vitro and in vivo. This promoter is highly responsive to the transcription factor neurogenin2 (Ngn2), which is a direct upstream activator of RP58 expression. Using in utero electroporation, we demonstrate that RP58 gene promoter activity is first detected in a subpopulation of pin-like VZ cells, then prominently activated in migrating multipolar cells in the multipolar cell accumulation zone (MAZ) located just above the VZ. In dissociated primary cultured cortical neurons, RP58 promoter activity mimics in vivo expression patterns from a molecular standpoint that RP58 is expressed in a fraction of Sox2-positive progenitor cells, Ngn2-positive neuronal committed cells, and Tuj1-positive young neurons, but not in Dlx2-positive GABAergic neurons. Finally, we show that Cre recombinase expression under the control of the RP58 gene promoter is a feasible tool for conditional gene switching in post-mitotic multipolar migrating young neurons in the developing cerebral cortex.

Tuberothalamic artery infarctions following coil embolization of ruptured posterior communicating artery aneurysms with posterior communicating artery sacrifice

BACKGROUND AND PURPOSE

Ischemic complications after coil embolization of the PcomA aneurysms are not thoroughly understood, especially in cases in which the PcomA is sacrificed. Our purpose was to examine the preoperative angiographic features and pattern of postoperative cerebral infarctions exhibited by patients who underwent embolization of ruptured PcomA aneurysms with PcomA sacrifice.

MATERIALS AND METHODS

A retrospective review identified 14 patients with ruptured PcomA aneurysms who underwent embolization of the aneurysms in combination with PcomA sacrifice. Preoperative angiographic data, including the Allcock test, postoperative DWI, and neurologic status, were examined.

RESULTS

Elimination of the aneurysm was complete in all cases. Postoperative DWI indicated 7 cases with infarctions (infarction group) and 7 cases without infarctions (noninfarction group). All patients in the infarction group developed infarctions in the vicinity of the tuberothalamic artery. In all 14 cases, a preoperative Allcock test demonstrated a retrograde filling of the PcomA through the P1 segment. The incidence of negative visualizations of the P1 segment on vertebral angiograms was significantly higher in the infarction group (100%) than in the noninfarction group (0%; P = .00058). The mean PcomA diameters, PcomA/P1 ratios, and aneurysm sizes observed in the infarction group were significantly greater than those in the noninfarction group (P < .05, P < .01, and P < .02, respectively). Tuberothalamic artery infarction caused hemiparesis and memory disturbance, which were associated with unfavorable outcomes.

CONCLUSIONS

After the coil occlusion of ruptured PcomA aneurysms with PcomA sacrifice, tuberothalamic artery infarctions tended to occur in cases exhibiting negative visualization of the P1 segment, even when collateral flow was observed with the Allcock test.

Dynamic instability of central airways and peripheral airspace in rat lungs perfused with cold preservation solutions

BACKGROUND/AIMS

For lung preservation, one of two types of solutions is commonly employed: Euro-Collins (EC) or low potassium dextran glucose (LPDG). These two solutions have been compared regarding biological, morphometrical and physiological outcomes in many experiments. However, the dynamic mechanics of perfused lung are not well understood because the dynamic characteristics cannot be assessed under static conditions; hence, the primary goal of the present study was to assess this in perfused rat lungs during the preservation period, comparing EC with LPDG at 0 or 9 h at 4°C.

METHODS

Lung impedance was measured using a forced oscillation technique. Lung resistance and elastance values were obtained by the fast Fourier transform algorithm. The instability of central airways and heterogeneity of ventilation were estimated.

RESULTS

In the EC group, airway resistance and instability were high after perfusion, and the lung elastance was high and more heterogeneous after cold storage. In contrast, those parameters were stable in the LPDG group during cold storage.

CONCLUSION

Such dynamic stability might facilitate the handling of lung grafts and eliminate injurious cyclic ventilation stress after reperfusion. Thus, we conclude that the impedance frequency characteristic represents a novel informative parameter for investigating lung preservation techniques.

Claudin as a target for drug development

Tight junctions (TJs) play pivotal roles in the fence and barrier functions of epithelial and endothelial cell sheets. Since the 1980s, the modulation of the TJ barrier has been utilized as a method for drug absorption. Over the last decade, the structural and functional biochemical components of TJs, such as occludin and claudin, have been determined, providing new insights into TJ-based pharmaceutical therapy. For example, the modulation of the claudin barrier enhances the jejunal absorption of drugs, and claudin expression is deregulated in cancer cells. Claudin is a co-receptor for the hepatitis C virus. Moreover, claudin is modulated during inflammatory conditions. These findings indicate that claudins are promising drug targets. In this review, we discuss the seeds of claudin-based drug development, which may provide potential pharmaceutical breakthroughs in the future.

Genome-wide association study on bipolar disorder in the Bulgarian population

Bipolar disorder is a severe psychiatric disorder influenced by environmental and genetic factors. Genetic studies have implicated many variants in the disease's etiology but only few have been successfully replicated. We conducted a genome-wide association study (GWAS) on bipolar disorder in the Bulgarian population followed by a replication study of the top 100 single nucleotide polymorphisms (SNPs) showing the smallest P values. The GWAS was performed on 188 bipolar disorder patients and 376 control subjects genotyped on the Illumina 550 platform. The replication study was conducted on 122 patients and 328 controls. Although our study did not show any association P value that achieved genome-wide significance, and none of the top 100 SNPs reached the Bonferroni-corrected P value in the replication study, the plausible involvement of some variants cannot be entirely discarded. Three polymorphisms, rs8099939 [P = 2.12 × 10(-6), odds ratio (OR) = 1.95, 95% confidence interval (CI) = 1.43-2.67] in GRIK5, rs6122972 (P = 3.11 × 10(-6), OR = 2.02, 95% CI = 1.46-2.80) in PARD6B and rs2289700 (P = 9.14 × 10(-6), OR = 2.13, 95% CI = 1.53-2.95) in CTSH remained associated at a similar level after Mantel-Haenszel test for combining the results from the genome-wide and replication studies. A modest association was also detected for SNP rs1012053 (GWAS P = 4.50 × 10(-2)) in DGKH, which has already been reported as the most significant variant in a previous genome-wide scan on bipolar disorder. However, further studies using larger datasets are needed to identify variants with smaller effects that contribute to the risk of bipolar disorder.

A toxicological evaluation of a claudin modulator, the C-terminal fragment of Clostridium perfringens enterotoxin, in mice

Tight junctions (TJs) maintain cellular polarity between the apical and basolateral region of epithelial cells. Claudin, a tetra-transmembrane protein, plays a pivotal role in the barrier function of TJs. We previously found that a claudin modulator, the C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE), may be a promising candidate for improving the mucosal absorption of drugs. C-CPE is a fragment of enterotoxin, and putative CPE claudin receptors are highly expressed in liver and kidney. The safety and antigenicity of C-CPE must be evaluated for future clinical application. Therefore, we evaluated whether C-CPE administration in mice leads to tissue injury or production of antibodies. Intravenous administration of C-CPE at 5 mg/kg, which is a more than 25-fold higher dose than that used in a murine mucosal absorption model, did not increase biochemical markers of liver and kidney injury even after 11 injections once a week. Nasal C-CPE administration (2 mg/kg) once a week for 11 administrations also did not increase these biochemical markers, but 6 administrations of C-CPE resulted in elevation of C-CPE-specific serum IgG. These results indicate that development of a less antigenic claudin modulator will be essential for future clinical application of a C-CPE-based mucosal absorption enhancer.