Factor VIII A3 domain residues 1793-1795 represent a factor IXa-interactive site in the tenase complex.

BACKGROUND: Factor (F)VIII functions as a cofactor in the tenase complex responsible for conversion of FX to FXa by FIXa. Earlier studies indicated that one of the FIXa-binding sites is located in residues 1811-1818 (crucially F1816) of the FVIII A3 domain. A putative, three-dimensional structure model of the FVIIIa molecule suggested that residues 1790-1798 form a V-shaped loop, and juxtapose residues 1811-1818 on the extended surface of FVIIIa. AIM: To examine FIXa molecular interactions in the clustered acidic sites of FVIII including residues 1790-1798. METHODS AND RESULTS: Specific ELISA's demonstrated that the synthetic peptides, encompassing residues 1790-1798 and 1811-1818, competitively inhibited the binding of FVIII light chain to active-site-blocked Glu-Gly-Arg-FIXa (EGR-FIXa) (IC50; 19.2 and 42.9 µM, respectively), in keeping with a possible role for the 1790-1798 in FIXa interactions. Surface plasmon resonance-based analyses demonstrated that variants of FVIII, in which the clustered acidic residues (E1793/E1794/D1793) or F1816 contained substituted alanine, bound to immobilized biotin labeled-Phe-Pro-Arg-FIXa (bFPR-FIXa) with a 1.5-2.2-fold greater KD compared to wild-type FVIII (WT). Similarly, FXa generation assays indicated that E1793A/E1794A/D1795A and F1816A mutants increased the Km by 1.6-2.8-fold relative to WT. Furthermore, E1793A/E1794A/D1795A/F1816A mutant showed that the Km was increased by 3.4-fold and the Vmax was decreased by 0.75-fold, compared to WT. Molecular dynamics simulation analyses revealed the subtle changes between WT and E1793A/E1794A/D1795A mutant, supportive of the contribution of these residues for FIXa interaction. CONCLUSION: The 1790-1798 region in the A3 domain, especially clustered acidic residues E1793/E1794/D1795, contains a FIXa-interactive site.

The spleen is the major site for the development and expansion of inhibitor producing-cells in hemophilia A mice upon FVIII infusion developing high-titer inhibitor.

BACKGROUND: Hemophilia A (HA) is a hereditary bleeding disorder caused by defects in endogenous factor (F)VIII. Approximately 30 % of patients with severe HA treated with FVIII develop neutralizing antibodies (inhibitors) against FVIII, which render the therapy ineffective. The managements of HA patients with high-titter inhibitors are especially challenging. Therefore, it is important to understand the mechanism(s) of high-titer inhibitor development and dynamics of FVIII-specific plasma cells (FVIII-PCs). AIMS: To identify the dynamics of FVIII-PCs and the lymphoid organs in which FVIII-PCs are localized during high-titer inhibitor formation. METHODS AND RESULTS: When FVIII-KO mice were intravenously injected with recombinant (r)FVIII in combination with lipopolysaccharide (LPS), a marked enhancement of anti-FVIII antibody induction was observed with increasing FVIII-PCs, especially in the spleen. When splenectomized or congenitally asplenic FVIII-KO mice were treated with LPS + rFVIII, the serum inhibitor levels decreased by approximately 80 %. Furthermore, when splenocytes or bone marrow (BM) cells from inhibitor+ FVIII-KO mice treated with LPS + rFVIII were grafted into immune-deficient mice, anti-FVIII IgG was detected only in the serum of splenocyte-administered mice and FVIII-PCs were detected in the spleen but not in the BM. In addition, when splenocytes from inhibitor+ FVIII-KO mice were grafted into splenectomized immuno-deficient mice, inhibitor levels were significantly reduced in the serum. CONCLUSION: The spleen is the major site responsible for the expansion and retention of FVIII-PCs in the presence of high-titer inhibitors.

Modified expi293 cell culture system using piggyBac transposon enables efficient production of human FVIII.

Human blood coagulation factor VIII (hFVIII) is used in hemostatic and prophylactic treatment of patients with hemophilia A. Biotechnological innovations have enabled purification of the culture medium of rodent or human cells harboring the hFVIII expression cassette. However, cell lines express hFVIII protein derived from an exogenous expression vector at a lower level than most other proteins. Here, we describe hFVIII production using piggyBac transposon and the human-derived expi293F cell line. Use of a drug selection protocol, rather than transient expression protocol, allowed cells harboring hFVIII expression cassettes to efficiently produce hFVIII. In heterogeneous drug-selected cells, the production level was maintained even after multiple passages. The specific activity of the produced hFVIII was comparable to that of the commercial product and hFVIII derived from baby hamster kidney cells. We also applied codon optimization to the hFVIII open reading frame sequences in the transgene, which increased production of full-length hFVIII, but decreased production of B-domain-deleted human FVIII (BDD-hFVIII). Low transcriptional abundance of the hF8 transgene was observed in cells harboring codon-optimized BDD-hFVIII expression cassettes, which might partially contribute to decreased hFVIII production. The mechanism underlying these distinct outcomes may offer clues to highly efficient hFVIII protein production.

Communicating Syringomyelia.

BACKGROUND: Communicating syringomyelia can develop in association with hydrocephalus, with communication between syringomyelia and the fourth ventricle a representative neuroimaging finding. CASE DESCRIPTION: A 51-year-old woman presented with slowly progressive bladder dysfunction and scoliosis. She had a nonfunctioning cerebrospinal fluid shunt that had been placed after birth for neonatal hydrocephalus. Tetraventricular enlargement and a holocord syrinx were noted in neuroimaging findings, while phase contrast magnetic resonance imaging and ventriculography revealed communication between the syrinx and fourth ventricle via a dilated central canal. Placement of a de novo ventriculoperitoneal shunt led to collapse of the syringomyelia, though apparent improvement of clinical symptoms was not obtained. CONCLUSIONS: Communicating syringomyelia can develop as a late complication in patients with shunted hydrocephalus. In the majority of reported cases, shunt revision has been shown to be effective, though some cases require posterior fossa decompression and exploration.

Functional connectivity analysis and prediction of cognitive change after carotid artery stenting.

OBJECTIVE: The neurocognitive course of patients who have undergone cerebral revascularization has been the subject of many studies, and the reported effects of carotid artery stenting (CAS) on cognitive function have varied from study to study. The authors hypothesized that cognitive amelioration after CAS is associated with alteration of the default mode network (DMN) connectivity, and they investigated the correlation between functional connectivity (FC) of the DMN and post-CAS changes in cognitive function in order to find a clinical marker that can be used to predict the effect of cerebral revascularization on patients' cognitive function in this preliminary exploratory study. METHODS: The authors examined post-CAS changes in cognitive function in relation to FC in patients treated for unilateral carotid artery stenosis. Resting-state functional MRI (rs-fMRI) was performed with a 3-T scanner before and 6 months after CAS in 8 patients. Neuropsychological tests (Wechsler Adult Intelligence Scale III and Wechsler Memory Scale-Revised) were administered to each patient before and 6 months after CAS. The DMN was mapped for each patient through independent component analysis of the rs-fMR images, and the correlation between FC of the DMN and post-CAS change in cognitive function was analyzed on a voxel level. Multivariable regression analysis was performed to identify preoperative factors associated with a post-CAS change in cognitive function. RESULTS: Post-CAS cognitive function varied between patients and between categories of neuropsychological tests. Although there was no significant overall improvement in Working Memory scores after CAS, post-CAS Working Memory scores changed in negative correlation with changes in FC between the DMN and the precentral/superior frontal gyrus and between the DMN and the middle frontal gyrus. In addition, the preoperative FC between those areas correlated positively with the post-CAS improvement in working memory. CONCLUSIONS: FC between the DMN and working memory-related areas is closely associated with improvement in working memory after CAS. Preoperative analysis of FC of the DMN may be useful for predicting postoperative improvement in the working memory of patients being treated for unilateral stenosis of the extracranial internal carotid artery.Clinical trial registration no.: UMIN000020045 (www.umin.ac.jp/ctr/index.htm).

Application of Freeze-Dried Powders of Genetically Engineered Microbial Strains as Adsorbents for Rare Earth Metal Ions.

The adsorption behaviors of the rare earth metal ions onto freeze-dried powders of genetically engineered microbial strains were compared. Cell powders obtained from four kinds of strains, Bacillus subtilis 168 wild type (WT), lipoteichoic acid-defective (ΔLTA), wall teichoic acid-defective (ΔWTA), and cell wall hydrolases-defective (EFKYOJLp) strains, were used as an adsorbent of the rare earth metal ions at pH 3. The adsorption ability of the rare earth metal ions was in the order of EFKYOJLp > WT > ΔLTA > ΔWTA. The order was the same as the order of the phosphorus quantity of the strains. This result indicates that the main adsorption sites for the ions are the phosphate groups and the teichoic acids, LTA and WTA, that contribute to the adsorption of the rare earth metal ions onto the cell walls. The contribution of WTA was clearly greater than that of LTA. Each microbial powder was added to a solution containing 16 kinds of rare earth metal ions, and the removals (%) of each rare earth metal ion were obtained. The scandium ion showed the highest removal (%), while that of the lanthanum ion was the lowest for all the microbial powders. Differences in the distribution coefficients between the kinds of lanthanide ions by the EFKYOJLp and ΔWTA powders were greater than those of the other strains. Therefore, the EFKYOJLp and ΔWTA powders could be applicable for the selective extraction of the lanthanide ions. The ΔLTA powder coagulated by mixing with a rare earth metal ion, although no sedimentation of the WT or ΔWTA powder with a rare earth metal ion was observed under the same conditions. The EFKYOJLp powder was also coagulated, but its flocculating activity was lower than that of ΔLTA. The ΔLTA and EFKYOJLp powders have a long shape compared to those of the WT or ΔWTA strain. The shapes of the cells will play an important role in the sedimentation of the microbial powders with rare earth metal ions. As the results, three kinds of the genetically engineered microbial powders revealed unique adsorption behaviors of the rare earth metal ions.

Cilostazol minimizes venous ischemic injury in diabetic and normal rats.

We evaluated the effects of cilostazol on venous infarction produced by a photothrombotic two-vein occlusion (2VO) model in diabetic and control rats. The cerebral blood flow (CBF) between the occluded veins was measured by laser Doppler flowmetry for 4 hours after 2VO. Infarct size and immunohistochemistry were evaluated 24, 48, 96, and 168 hours after 2VO. Cilostazol was administered 1 hour after 2VO, and thereafter at a continuous oral dose of 60 mg/kg per day. Cilostazol reduced the infarct size, and the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)-positive apoptotic and B-cell lymphoma 2-associated X protein (Bax)-positive cells, and improved the CBF in control rats. In diabetic rats, cilostazol reduced the infarct size, and the number of TUNEL-positive apoptotic and Bax-positive cells, 96 and 168 hours after 2VO, but did not improve the CBF 4 hours after 2VO. Cilostazol increased the number of B-cell lymphoma 2 (Bcl-2)-positive cells in both strains 48, 96, and 168 hours after 2VO, but did not improve vessel wall thickness or collagen deposits. Cilostazol appeared to limit venous infarcts by improving the penumbral CBF in nondiabetic rats, and inhibited pro-apoptotic changes through Bcl-2 overexpression, without improving the CBF in diabetic rats.

Neuroprotection with intraventricular brain-derived neurotrophic factor in rat venous occlusion model.

BACKGROUND: The increasing number of neurosurgical procedures for elderly patients and the development of skull base neurosurgery have increased interest in cerebral venous injury that might occur in a neurosurgical setting. Brain-derived neurotrophic factor (BDNF) may have neuroprotective effects against cerebral venous ischemia. OBJECTIVE: To investigate the intraventricular effects of BDNF infusion on infarct size, suppression of apoptosis, and regional cerebral blood flow (rCBF) in cerebral venous ischemic lesions in a rat 2-vein occlusion model. METHODS: Thirty-three male Wistar rats were randomly divided into BDNF-treated and vehicle control groups; each group was further randomly divided into 2-day and 7-day postocclusion groups. BDNF (2.1 µg/day) or vehicle was delivered continuously via intraventricular infusion pumps. Two adjacent contralateral cortical veins were then photochemically occluded. Two and 7 days after occlusion, we histologically measured ratios of infarct volume to contralateral hemisphere volume and counted (2-day group) terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)-positive apoptotic cells in the penumbra. rCBF was measured via full-field laser perfusion imaging. RESULTS: The mean infarct volume after venous occlusion was significantly smaller in BDNF-treated rats than in controls at 2 days (1.49 ± 1.44% vs 3.66 ± 1.51%; P < .05) and 7 days (0.93 ± 0.47% vs 1.69 ± 0.58%; P < .05). Two days after occlusion, there were significantly fewer TUNEL-positive apoptotic cells in the BDNF-treated rats (17.0 ± 15.1) than in the controls (39.0 ± 19.6; P < .05). There were no differences in rCBF. CONCLUSION: After 2-vein occlusion, continuous intraventricular administration of BDNF protected the cerebral cortex against apoptosis and reduced infarct size without affecting rCBF.

Enhanced cerebral ischemic lesions after two-vein occlusion in diabetic rats.

The two-vein occlusion (2VO) model is known to be useful for ischemic penumbra studies in vivo. It was applied here to examine sequential changes of regional cerebral blood flow (CBF) and cerebral venous infarction in normal (Long-Evans Tokushima Otsuka, LETO) and diabetic (Otsuka Long-Evans Tokushima Fatty, OLETF) rats. The aim of our study was to examine and compare the ischemic pathogenesis related to regional changes in cerebral blood flow (CBF) induced with 2VO in diabetic OLETF and non-diabetic LETO rats. Two cortical veins were occluded photochemically by using rose bengal dye in 10 OLETF and 10 LETO rats. All animals were killed with perfusion fixation at 48 h after 2VO. Bax and Bcl-2 staining was performed along with the terminal deoxynucleotidyl transderase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay to examine the relationship to single-cell death. Smooth muscle actin and Van Gieson's elastic staining were done for assessment of thickening of the vessel walls. Not only the volume of cerebral cortex affected by 2VO-induced venous infarction was increased in diabetic OLETF rats, but we also observed significantly reduced CBF at 90 min after 2VO, coupled with increased apoptosis in and around ischemic lesions. Morphologically, OLETF rats demonstrated marked thickening of the walls in the small cerebral vessels with perivascular fibrosis, indicating more severe cerebral microvascular atherosclerotic changes as compared to their non-diabetic LETO counterparts. The OLETF rat thus appears to be an excellent animal model for studying the diabetic enhancement of venous ischemia induced by 2VO.

[Case report of spontaneous cervical epidural hematoma in elderly].

Spontaneous spinal epidural hematomas (SSEH) are relatively rare clinical entities and associated with coagulopathies, tumors, or vascular malformation. In addition, these are often neurosurgical emergencies; therefore, prompt diagnosis and treatment are paramount. We reported a case of an 87-year-old woman with spontaneous cervical epidural hematoma. She presented with the sudden onset of neck pain, rt. upper arm sensory disturbance and rt. hemiparesis. MRI revealed a C3-Th1 dorsally placed extradural lesion. The lesion was iso-to hypointense on T1-weighted images and was hyperintense on T2-weighted images. She underwent surgery within 9 hours after symptom onset, removal of hematoma through the right hemilaminectomy was performed. She was a very high age, but she was discharged from the hospital without neurological deficit. To obtain good prognosis for patients with SSEH, early diagnosis and treatment are important. We also review the current literature concerning diagnosis and treatment of SSEH.

Prefabrication of vascularized bone graft using guided bone regeneration.

This article describes the prefabrication of a vascularized bone graft composed of autologous particulate cancellous bone and marrow (PCBM), a vessel bundle, and a biodegradable membrane. The PCBM was placed around the saphenous vessel bundle of rats and rolled with a biodegradable membrane of L-lactide-epsilon-caprolactone copolymer to prepare the prefabricated vascularized bone graft (group A). As controls, combinations of PCBM and membrane (group B), vessel bundle and membrane (group C), and PCBM and vessel bundle (group D) were prepared. A radiographic study revealed radio-opacity in the implantation site of group A 1 week later, in contrast to the other groups. Newly formed bone in the membrane roll was histologically confirmed, and neomicrovasculature circulating from the vessel bundle through the newly formed bone tissue was observed. The increase in alkaline phosphatase activity and osteocalcin content was significant for the group A preparation compared with the other groups. We concluded that the combination of autologous PCBM, a vessel bundle, and a biodegradable membrane was promising in the prefabrication of vascularized bone with good blood circulation.