S4 Segment Research Articles

Modeling the Structure-Activity Relationship of Arbidol Derivatives and Other SARS-CoV-2 Fusion Inhibitors Targeting the S2 Segment of the Spike Protein.

Umifenovir (Arbidol) has been reported to exhibit some degree of efficacy in multiple clinical trials for the treatment of COVID-19 as a monotherapy. It has also demonstrated synergistic inhibition of SARS-CoV-2 with other direct-acting antivirals such as Remdesivir. A computational approach was used to identify the most favorable binding site to the SARS-CoV-2 Spike S2 segment and to perform virtual screening. Compounds selected from modeling were evaluated in a live SARS-CoV-2 infection assay. An Arbidol (ARB) derivative with substitutions at both the C-4 and C-6 positions was found to exhibit a modest improvement in activity and solubility properties in comparison to ARB. However, all of the derivatives were found to only be partial inhibitors, rather than full inhibitors in a virus-induced cytopathic effect-based assay. The binding mode is also corroborated by parallel modeling of a series of oleanolic acid trisaccharide saponin fusion inhibitors shown to bind to the S2 segment. Recently determined experimental structures of the Spike protein allowed atomic resolution modeling of fusion inhibitor binding as a function of pH, and the implications for the molecular mechanism of direct-acting fusion inhibitors targeting the S2 segment are discussed.

Infantile hemangiomas: risk factors for complications, recurrence and unaesthetic sequelae

BackgroundInfantile hemangiomas (IH) occur in approximately 4% to 10% of the pediatric population. The identification of clinical subtypes and conditions that indicate increased risk for complications is essential for therapeutic success. ObjectivesTo identify risk factors for complications, recurrence and unaesthetic sequelae. MethodsRetrospective cohort of patients with infantile hemangiomas undergoing follow-up at the Dermatology Service of Universidade Federal de Ciências da Saúde de Porto Alegre, between 2006 and 2018. Results190 patients were included; 24% had some type of complication, ulceration being the most frequent, and 86% required treatment. On correlation, ulceration was statistically related to mixed IH (p = 0.004), segmental IH (p < 0.01) and location in the gluteal region (p = 0.001). The mean time of treatment with propranolol was 12.7 months. Patients with PHACES syndrome and segmental infantile hemangioma required longer treatment (p < 0.001 and p = 0.0407, respectively), as well as those who started treatment after five months of life (p < 0.0001). Recurrence occurred in 16.6% of the treated patients, all-female; 94% were located on the head and neck (mainly on the upper eyelid, cyrano, S3 segment, and with parotid involvement); 61% and 38.8% were of the mixed and deep subtypes, respectively. Approximately 1/3 of the patients had some unaesthetic sequelae. Study limitationsAs this is a retrospective study, data and photos of some patients were lost. ConclusionsMixed and segmental hemangiomas are risk factors for ulceration and sequelae. Recurrence occurs more often in females and segmental hemangiomas. Segmental infantile hemangioma and PHACES syndrome require a longer time of treatment. Specific protocols are required for infantile hemangiomas with a high risk of recurrence.

Applicable safety analysis and biomechanical study of iliosacral triangular osteosynthesis

BackgroundThe aim of this study was to investigate the applicable safety and biomechanical stability of iliosacral triangular osteosynthesis (ITO) through 3D modeling and finite element (FE) analysis.MethodsPelvic CT imaging data from 100 cases were imported into Mimics software for the construction of 3D pelvic models. The S2-alar-iliac (S2AI) screws and S2 sacroiliac screws were placed in the S2 segment with optimal distribution and their compatibility rate on the S2 safe channel was observed and analyzed. In the FE model, the posterior pelvic ring was fixed with two transsacral screws (TTS), triangular osteosynthesis (TO) and ITO, respectively. Four different loading methods were implemented in sequence to simulate the force in standing, flexion, right bending, and left twisting, respectively. The relative displacement and change in relative displacement of the three fixing methods were recorded and analyzed.ResultsThe theoretical compatibility rate of S2AI screw and S2 sacroiliac screw in S2 segment was 94%, of which 100% were in males and 88% in females. In the FE model, in terms of overall relative displacement, TTS group showed the smallest relative displacement, the ITO group showed the second smallest, and the TO group the largest relative displacement. The change in relative displacement of the TTS group displayed the smaller fluctuations in motion. The change in relative displacement of the TO group under right bending and left twisting displayed larger fluctuations, while the ITO group under flexion displayed larger fluctuations.ConclusionsThe simultaneous placement of S2AI screw and S2 sacroiliac screw in the S2 segment is theoretically safe. Although the biomechanical stability of ITO is slightly lower than TTS, it is better than TO, and can be used as a new method for the treatment of posterior pelvic ring injuries.

Voltage sensor movements of CaV1.1 during an action potential in skeletal muscle fibers

In excitation-contraction coupling (ECC), when the skeletal muscle action potential (AP) propagates into the transverse tubules, it modifies the conformational state of the voltage-gated calcium channels (CaV1.1). CaV1.1 serves as the voltage sensor for activation of calcium release from the sarcoplasmic reticulum (SR); however, many questions about this function persist. CaV1.1 α1 subunits contain four distinct homologous domains (I-IV). Each repeat includes six transmembranal helical segments; the voltage-sensing domain (VSD) is formed by S1-S4 segments, and the pore domain is formed by helices S5-S6. Because, in other voltage-gated channels, individual VSDs appear to be differentially involved in specific aspects of channel gating, here we thus hypothesized that not all the VSDs in CaV1.1 contribute equally to calcium-release activation. Yet, the voltage-sensor movements during an AP (the physiological stimulus for the muscle fiber) have not been previously measured in muscle. Reorientation of VSDs I-IV in CaV1.1 during an AP should generate a small but measurable electrical current. Still, neither the voltage-sensor charge movement during the AP nor the contribution of the individual VSDs to voltage-gated calcium release have been previously monitored. Here, we electrically monitor VSD movements using an AP voltage-clamp technique applied to muscle fibers. We introduce AP-fluorometry, a variant of the functional site-directed fluorescence, to track the movement of each VSD via a cysteine substitution on the extracellular region of S4 of each VSD and its labeling with a cysteine-reacting fluorescent probe, which served as an optical reporter of local rearrangements. Independent optical recordings of AP and calcium transients were performed to establish the temporal correlation between AP, AP-elicited charge movement, VSDs conformational changes, and calcium release flux. Our results support the hypothesis that not all VSDs in CaV1.1 contribute to ECC.

CaV1.1 defects in hypokalemic periodic paralysis and harnessing multiple approaches for therapeutic intervention

The recurrent attacks of weakness in hypokalemic periodic paralysis (HypoPP) are caused by failure to maintain the resting potential, with paradoxical depolarization in low K+. Remarkably, 24 out of 25 HypoPP mutations are R/X substitutions in S4 segments of voltage-sensing domains of CaV1.1 (70% of cases) or NaV1.4 (10% of cases). Expression studies in oocytes and murine muscle show anomalous gating pore leakage currents (ω-pore) for six of eight CaV1.1-HypoPP mutations, with one exception being the charge-conserving R897K. The proposed consensus pathomechanism, whereby a gating pore leak predisposes to paradoxical depolarization in low K+, is now verified by continuous recording of Vm. Selective measurement of voltage-dependent Ca2+ release, in "healthy appearing" HypoPP fibers, shows only a modest decrease in the Ca2+-dependent peak fluorescence (Oregon green 488/EGTA), and supports the notion that stabilizing Vrest will be sufficient to prevent low-K+-induced loss of force. In our knockin mouse models of HypoPP (CaV1.1-R528H and NaV1.4-R669H), pretreatment with K+-channel openers protects against the loss of force with a 2 mM K+ challenge. Alternatively, gene editing offers the possibility of sustained protection from attacks of weakness, and may prevent the late-onset permanent myopathy. In a proof-of-principle study of cultured myoblasts and in vivo electroporation, we show selective editing of the mutant HypoPP allele, without compromise of the WT allele, using CRISPR/Cas-mediated indel formation to destroy the HypoPP allele or a CRISPR/Cas base editor to correct the missense mutation.

Social Media Validation for Pre-Screened Ontologies As a Driver for Biomolecular Interaction Significance in COVID-19 and Hematological Malignancies

With the rise of social media use during the COVID-19 pandemic, impressions from online content can affect behavioral changes resulting in exacerbating disparities in care. Thus, there exists a need to utilize social media platforms, like Twitter, to help augment preparedness, especially at the intersection between oncology and COVID-19, where tweets could help hint at potential biomolecular interactions.To address this, a study was developed to assess relationship and ontologies on the interaction between hematological malignancies and COVID-19 on Twitter. Ontologies are groupings of terms and related identifiers, such as genes, for general search terms, such as “Blood Cancer”, were found utilizing the Human Phenotype Ontology. These were combined with the term “COVID-19” and used as search terms for Twitter's Standard Search API. The resulting tweets were cross-checked to assess if they included any of the other terms or genes related to the starting ontologies to then determine how many terms or genes each tweet was associated with. Once the most associated tweets to the ontologies were found, the genes related to those ontologies were utilized to find biological structures within the AlphaFold EMBL database, before being used in binding using HEX Docking software's shape based binding tool in 3D. Finally, Root Mean Square (RMS) Deviations were performed between the top 2000 conformations for each bound structure to determine if the binding was statistically significant.Results showed strong clustering of top tweets around keyword combinations. In the case of the starting entry, “Blood COVID-19”, the ontologies that were found were linked to 45 terms that each had 100 or more tweets linked to them (Figure 1a). One such term of significance was Acute Myeloid Leukemia, which was linked to the gene BRCA1. The biological significance of the molecular interaction between BRCA1 and SARS CoV-2 was determined using the predicted protein structure from the AlphaFold-EMBL database for BRCA1 and the RCSB Protein Bank structure for the SARS CoV-2 spike (PDB# 6VSB), which can be found in Figure 1b. This interaction was found to be significant based on the average RMS Deviation of 82.97 Angstroms that ranged across the top 2000 conformation. Each model had an average RMS of 85.05 Angstroms between BRCA1 and the COVID-19 spike, with binding occurring on the spike's carbohydrate recognition domain within its S1 segment that is typically used for cell entry. Thus, human phenotype ontology was effective in classifying tweets to specific biomolecular interactions.Therefore, this approach could be utilized to proactively influence treatment designs for blood cancer patients infected with COVID-19, as well as in other areas where medical illnesses are already well defined by ontologies or other literature data. Forward looking, future studies will help to ensure that terms that are not well characterized by ontologies can still be utilized in this type of analysis by employing de novo ontology production methods. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Anatomic Risk Factors for S1 Segment Superior Cerebellar Artery Aneurysm Rupture: A Radiologic Study on 81 Consecutive Patients

Due to treatment associated risks, it is still debatable which unruptured aneurysm should be treated. Anatomic and morphologic characteristics may aid to predict the rupture risk of superior cerebellar artery (SCA) aneurysm and possibly support in decision- making during treatment. To identify morphologic characteristics that could predict the rupture of SCA aneurysms. A retrospective analysis of computed tomography angiography images of 81 consecutive patients harboring SCA aneurysm who were treated between 1980 to 2014 at Helsinki University Hospital was performed. Of the 81 analyzed SCA aneurysms, 30 (37%) were unruptured and remaining 51 (63%) presented with subarachnoid hemorrhage. The mean ± SD size of unruptured SCA aneurysms was 6.2 ± 6.3 mm; mean sizeofruptured SCA aneurysms was 5.9 ± 5.4 mm. The mean±SD aspect ratio was 0.9 ± 0.3 in unruptured and 1.14 ± 0.44 in ruptured SCA aneurysms. The mean ± SD degree angle between basilar artery and aneurysm was 74.7 ± 24.4 in unruptured and 65.9 ± 23 ruptured SCA aneurysms. Patients with ruptured SCA aneurysm showed significantly higheraspect ratio (Mann-Whitney U, P=0.01) and smalleraneurysm to basilar artery angle (Mann-Whitney U, P= 0.039). Aspect ratio >1.1 had 2.3 times higher risk of rupture (odds ration [OR] 2.3, 95% confidence interval [CI] 0.84-6.34). An aneurysm to basilar angle <70 degrees had 2.8 times higher risk of rupture (OR 2.75, 95% CI 1.086-6.96). Ruptured SCA aneurysms are usually small in size. Higher aspect ratio and smaller angle between SCA aneurysm and basilar artery had significantly higher risk of SCA (S1 segment) aneurysm rupture.

Early initial video-electro-encephalography combined with variant location predict prognosis of KCNQ2-related disorder

BackgroundThe clinical features of KCNQ2-related disorders range from benign familial neonatal seizures 1 to early infantile epileptic encephalopathy 7. The genotype-phenotypic association is difficult to establish.ObjectiveTo explore potential factors in neonatal period that can predict the prognosis of neonates with KCNQ2-related disorder.MethodsInfants with KCNQ2-related disorder were retrospectively enrolled in our study in Children’s Hospital of Fudan University in China from Jan 2015 to Mar 2020. All infants were older than age of 12 months at time of follow-up, and assessed by Bayley Scales of Infant and Toddler Development-Third Edition (BSID-III) or Wechsler preschool and primary scale of intelligence-fourth edition (WPPSI-IV), then divided into three groups based on scores of BSID-III or WPPSI-IV: normal group, mild impairment group, encephalopathy group. We collected demographic variables, clinical characteristics, neuroimaging data. Considered variables include gender, gestational age, birth weight, age of the initial seizures, early interictal VEEG, variant location, delivery type. Variables predicting prognosis were identified using multivariate ordinal logistic regression analysis.ResultsA total of 52 infants were selected in this study. Early interictal video-electro-encephalography (VEEG) (β = 2.77, 1.20 to 4.34, P = 0.001), and variant location (β = 2.77, 0.03 to 5.5, P = 0.048) were independent risk factors for prognosis. The worse the early interictal VEEG, the worse the prognosis. Patients with variants located in the pore-lining domain or S4 segment are more likely to have a poor prognosis.ConclusionsThe integration of early initial VEEG and variant location can predict prognosis. An individual whose KCNQ2 variant located in voltage sensor, the pore domain, with worse early initial VEEG background, often had an adverse outcome.

Binding Sites and the Mechanism of Action of Propofol and a Photoreactive Analogue in Prokaryotic Voltage-Gated Sodium Channels

Propofol, one of the most commonly used intravenous general anesthetics, modulates neuronal function by interacting with ion channels. The mechanisms that link propofol binding to the modulation of distinct ion channel states, however, are not understood. To tackle this problem, we investigated the prokaryotic ancestors of eukaryotic voltage-gated Na+ channels (Navs) using unbiased photoaffinity labeling (PAL) with a diazirine derivative of propofol (AziPm), electrophysiological methods, and mutagenesis. AziPm inhibits Nav function in a manner that is indistinguishable from that of the parent compound by promoting activation-coupled inactivation. In several replicates (8/9) involving NaChBac and NavMs, we found adducts at residues located at the C-terminal end of the S4 voltage sensor, the S4-S5 linker, and the N-terminal end of the S5 segment. However, the non-inactivating mutant NaChBac-T220A yielded adducts that were different from those found in the wild-type counterpart, which suggested state-dependent changes at the binding site. Then, using molecular dynamics simulations to further elucidate the structural basis of Nav modulation by propofol, we show that the S4 voltage sensors and the S4-S5 linkers shape two distinct propofol binding sites in a conformation-dependent manner. Supporting the PAL and MD simulation results, we also found that Ala mutations of a subset of adducted residues have distinct effects on gating modulation of NaChBac and NavMs by propofol. The results of this study provide direct insights into the structural basis of the mechanism through which propofol binding promotes activation-coupled inactivation to inhibit Nav channel function.

Single-Nucleus RNA Sequencing Identifies New Classes of Proximal Tubular Epithelial Cells in Kidney Fibrosis.

Proximal tubular cells (PTCs) are the most abundant cell type in the kidney. PTCs are central to normal kidney function and to regeneration versus organ fibrosis following injury. This study used single-nucleus RNA sequencing (snRNAseq) to describe the phenotype of PTCs in renal fibrosis. Kidneys were harvested from naïve mice and from mice with renal fibrosis induced by chronic aristolochic acid administration. Nuclei were isolated using Nuclei EZ Lysis buffer. Libraries were prepared on the 10× platform, and snRNAseq was completed using the Illumina NextSeq 550 System. Genome mapping was carried out with high-performance computing. A total of 23,885 nuclei were analyzed. PTCs were found in five abundant clusters, mapping to S1, S1-S2, S2, S2-cortical S3, and medullary S3 segments. Additional cell clusters ("new PTC clusters") were at low abundance in normal kidney and in increased number in kidneys undergoing regeneration/fibrosis following injury. These clusters exhibited clear molecular phenotypes, permitting labeling as proliferating, New-PT1, New-PT2, and (present only following injury) New-PT3. Each cluster exhibited a unique gene expression signature, including multiple genes previously associated with renal injury response and fibrosis progression. Comprehensive pathway analyses revealed metabolic reprogramming, enrichment of cellular communication and cell motility, and various immune activations in new PTC clusters. In ligand-receptor analysis, new PTC clusters promoted fibrotic signaling to fibroblasts and inflammatory activation to macrophages. These data identify unrecognized PTC phenotype heterogeneity and reveal novel PTCs associated with kidney fibrosis.

Spectral analysis of heart sounds associated with coronary artery disease

Objective. The aim of this study was to find spectral differences of diagnostic interest in heart sound recordings of patients with coronary artery disease (CAD) and healthy subjects. Approach. Heart sound recordings from three studies were pooled, and patients with clear diagnostic outcomes (positive: CAD and negative: Non-CAD) were selected for further analysis. Recordings from 1146 patients (191 CAD and 955 Non-CAD) were analyzed for spectral differences between the two groups using Welch’s spectral density estimate. Frequency spectra were estimated for systole and diastole segments, and time-frequency spectra were estimated for first (S1) and second (S2) heart sound segments. An ANCOVA model with terms for diagnosis, age, gender, and body mass index was used to evaluate statistical significance of the diagnosis term for each time-frequency component. Main results. Diastole and systole segments of CAD patients showed increased energy at frequencies 20–120 Hz; furthermore, this difference was statistically significant for the diastole. CAD patients showed decreased energy for the mid-S1 and mid-S2 segments and conversely increased energy before and after the valve sounds. Both S1 and S2 segments showed regions of statistically significant difference in the time-frequency spectra. Significance. Results from analysis of the diastole support findings of increased low-frequency energy from previous studies. Time-frequency components of S1 and S2 sounds showed that these two segments likely contain heretofore untapped information for risk assessment of CAD using phonocardiography; this should be considered in future works. Further development of features that build on these findings could lead to improved acoustic detection of CAD.

Global Sagittal Alignment and Clinical Outcomes after 1-3 Short-Segment Lumbar Fusion in Degenerative Spinal Diseases.

Study DesignLevel III retrospective study.PurposeWe investigated the impact of short-segment lumbar fusion on the restoration of global sagittal alignment and the correlations between spino-pelvic parameters and clinical outcomes.Overview of LiteratureSagittal imbalance leads to energy consumption and pain in maintaining a standing position. For adult spinal deformity, it is critical to create optimal lumbar lordosis (LL) in order to achieve restoration of sagittal imbalance. However, surgeons do not pay attention to correcting LL in short-segment lumbar fusion.MethodsA total of 69 patients with transforaminal lumbar interbody fusion (TLIF) for degenerative spinal disease were evaluated with a minimum 2-year follow-up. All patients underwent TLIF with hyper-lordotic angle cages to achieve higher LL. Radiological spino-pelvic parameters including sagittal vertical axis (SVA) and clinical outcomes using the Oswestry Disability Index (ODI) and Numeric Rating Scale (NRS) were evaluated.ResultsThe average LL was 35.8°±9.9° before surgery, 42.3°±9.3° 1 year after surgery, and 40.3°±10.2° 2 years after surgery (p<0.01). The average SVA was 43.1±6.2 mm before surgery, 21.2±4.9 mm 1 year after surgery, and 34.0±4.7 mm 2 years after surgery (p<0.01). The average LL and SVA improved in two- or three-segment fusion, but not in one-segment fusion. The correlation between ΔLL and ΔSVA was significant in all segment fusions. The correlation between ΔLL and ΔSVA was more significant at the L4–5 and L5–S1 segments than at L3–4. ODI was significantly correlated with SVA (p<0.05). NRS showed no correlation with the radiological parameters.ConclusionsTwo- or three-segment lumbar fusion using hyper-lordotic angle cages improved LL and SVA. A significant correlation between the correction of LL and SVA was found. Higher correction of LL using hyper-lordotic angle cages is thus recommended in short-segment lumbar fusion, since postoperative improvements of SVA significantly affect clinical outcomes.

Negative biomechanical effects of large grade nuclectomy in the transforaminal endoscopic discectomy increased the risk of adjacent segment diseases: A finite element study

PurposeThe protection of articular processes (AP) in the transforaminal endoscopic discectomy (TED) was proven to optimise post-operative biomechanical environments. Published studies reported a large grade of nuclectomy leading to poor prognosis, but the underlying biomechanical mechanism was unclearly illustrated. This study aimed to investigate the changes of biomechanical environments after an in-out TED with intact AP and a large grade of nuclectomy and an out-in TED with limited foraminoplasty and a smaller grade of nuclectomy. MethodsA previously constructed and validated lumbo–sacral model was used in this study, and in-out TED with intact AP and out-in TED with limited foraminoplasty, a smaller grade of nuclectomy was simulated. Biomechanical changes in the L5–S1 segment related to the degeneration acceleration were computed under different directional loading conditions. ResultsPost-operative biomechanical changes after the out-in TED with limited foraminoplasty were slight, except for the facet contact pressure under the extension position. By contrast, significant biomechanical deterioration, both in the adjacent disc and zygapophyseal joints, is observed under extension in the model after the in-out TED with large nuclectomy. ConclusionA large grade of nuclectomy is regarded as an independent risk factor of adjacent segment disease in the caudal functional spinal unit after the in-out TED.

Mutation location and IKs regulation in the arrhythmic risk of long QT syndrome type 1: the importance of the KCNQ1 S6 region.

Mutation type, location, dominant-negative IKs reduction, and possibly loss of cyclic adenosine monophosphate (cAMP)-dependent IKs stimulation via protein kinase A (PKA) influence the clinical severity of long QT syndrome type 1 (LQT1). Given the malignancy of KCNQ1-p.A341V, we assessed whether mutations neighbouring p.A341V in the S6 channel segment could also increase arrhythmic risk. Clinical and genetic data were obtained from 1316 LQT1 patients [450 families, 166 unique KCNQ1 mutations, including 277 p.A341V-positive subjects, 139 patients with p.A341-neighbouring mutations (91 missense, 48 non-missense), and 900 other LQT1 subjects]. A first cardiac event represented the primary endpoint. S6 segment missense variant characteristics, particularly cAMP stimulation responses, were analysed by cellular electrophysiology. p.A341-neighbouring mutation carriers had a QTc shorter than p.A341V carriers (477 ± 33 vs. 490 ± 44 ms) but longer than the remaining LQT1 patient population (467 ± 41 ms) (P < 0.05 for both). Similarly, the frequency of symptomatic subjects in the p.A341-neighbouring subgroup was intermediate between the other two groups (43% vs. 73% vs. 20%; P < 0.001). These differences in clinical severity can be explained, for p.A341V vs. p.A341-neighbouring mutations, by the p.A341V-specific impairment of IKs regulation. The differences between the p.A341-neighbouring subgroup and the rest of LQT1 mutations may be explained by the functional importance of the S6 segment for channel activation. KCNQ1 S6 segment mutations surrounding p.A341 increase arrhythmic risk. p.A341V-specific loss of PKA-dependent IKs enhancement correlates with its phenotypic severity. Cellular studies providing further insights into IKs-channel regulation and knowledge of structure-function relationships could improve risk stratification. These findings impact on clinical management.

Geodynamic and plate kinematic context of South China Sea subduction during Okinawa trough opening and Taiwan orogeny

The geodynamics and plate tectonics of the South China Sea (SCS)-Taiwan region since Miocene times are uncertain because the former extent and tectonic configuration of the subducted easternmost SCS along the Manila trench is uncertain. Here we unravel the regional kinematic context from main offshore constraints including published unfolding of the Manila slab from seismic tomography, which provides insight on restoring the subducted part of the SCS. We reconstruct a bayonet-shaped, stepped northern SCS continent-ocean boundary (COB) that consists of a northeastern SCS COB segment we call ‘S3’, trending N070° that roughly parallels the present SCS shelf; a 350-km long ~N-S trending segment S2 that steps north to Hualien; and, a third segment S1 that extends from east of Hualien beneath the Ryukyu subduction zone trending N085° that ends near Miyako Island in the Ryukyus.The distance between present COB and S1 gives extension through time in the Okinawa trough, with a maximum of ~100 ± 20 km extension since late Miocene (10 Ma). We interpret S1 as a zone of weakness since ~18 Ma that ruptured from Miyako Island to east of Hualien as a tear fault, with the Huatung basin-Philippine Sea plate (HB-PSP) subducting northwestward between the two sides of the tear fault. The Manila transcurrent fault initiated ~18 Ma ago at the onset of the tear and progressively moved eastward, creating the intra-oceanic Luzon arc, which began collision ~7 Ma ago along the EU margin. From ~7 to 6.5 Ma Taiwan was uplifted west of the Longitudinal valley. The Luzon arc and forearc basins were shortened within the Coastal range. Plate kinematic reconstructions from ~18 Ma to Present are synthesized in terms of continental or oceanic nature of the main PSP-HB and EU entities before their subduction that provide new understanding on Taiwan, PSP-SCS kinematics, and regional histories.

Drug Repurposing Patent Applications April–June 2021

Drug Repurposing Patent Applications April–June 2021

Voltage-gated calcium channels (Ca&lt;sub&gt;V&lt;/sub&gt;) in GtoPdb v.2021.3

Ca2+ channels are voltage-gated ion channels present in the membrane of most excitable cells. The nomenclature for Ca2+channels was proposed by [127] and approved by the NC-IUPHAR Subcommittee on Ca2+ channels [70]. Most Ca2+ channels form hetero-oligomeric complexes. The α1 subunit is pore-forming and provides the binding site(s) for practically all agonists and antagonists. The 10 cloned α1-subunits can be grouped into three families: (1) the high-voltage activated dihydropyridine-sensitive (L-type, CaV1.x) channels; (2) the high- to moderate-voltage activated dihydropyridine-insensitive (CaV2.x) channels and (3) the low-voltage-activated (T-type, CaV3.x) channels. Each α1 subunit has four homologous repeats (I-IV), each repeat having six transmembrane domains (S1-S6) and a pore-forming region between S5 and S6. Voltage-dependent gating is driven by the membrane spanning S4 segment, which contains highly conserved positive charges that respond to changes in membrane potential. All of the α1-subunit genes give rise to alternatively spliced products. At least for high-voltage activated channels, it is likely that native channels comprise co-assemblies of α1, β and α2-δ subunits. The γ subunits have not been proven to associate with channels other than the α1s skeletal muscle Cav1.1 channel. The α2-δ1 and α2-δ2 subunits bind gabapentin and pregabalin.

Abstract P160: Deficiency Of Angiotensin-converting Enzyme In Renal Proximal Convoluted Tubules Does Not Attenuate Atherosclerosis In Mice

Objective: Angiotensin-converting enzyme (ACE) is the enzyme to generate Angiotensin II (AngII), an important contributor to atherosclerosis. ACE is present in all 3 segments (S1, S2, and S3) of proximal tubular cells (PTCs), and AngII concentrations are higher in kidney than in plasma. The purpose of this study was to determine whether ACE in PTCs contributes to atherosclerosis in mice. Approach and Results: Female ACE floxed mice and male Ndrg1-Cre ERT2 +/- transgenic mice were bred to generate ACE f/f x Ndrg1-Cre ERT2 -/- (PTC-ACE +/+ ) and ACE f/f x Ndrg1-Cre ERT2 +/- (PTC-ACE -/- ) littermates. Male PTC-ACE +/+ (n=7) and PTC-ACE -/- (n=10) littermates in an LDL receptor -/- background were used for atherosclerosis study. After Cre genotyping using tail DNA, mice (both Cre ERT2 -/- and Cre ERT2 +/- ) were injected with 150 mg/kg/day of tamoxifen for 5 consecutive days at the age of 4-6 weeks. Two weeks after the last injection of tamoxifen, mice were fed a Western diet (Envigo, Diet #TD.88137) for 12 weeks to induce hypercholesterolemia. Blood pressure was measured using a tail-cuff system. No difference of blood pressure was detected between the two genotypes (PTC-ACE +/+ vs. PTC-ACE -/- : 126 ± 4 vs. 125 ± 3 mmHg; P = 0.763). All study mice were hypercholesterolemic, but plasma cholesterol concentrations were not different between the two genotypes (PTC-ACE +/+ vs. PTC-ACE -/- : 1376 ± 119 vs. 1543 ± 93 mg/dl; P = 0.28). PTC-specific deletion of ACE was confirmed after termination using immunostaining of ACE. In mice with Ndrg1-Cre ERT2 transgene, immunostaining of ACE in kidney section showed an absence of ACE in S1 and S2 of PTCs, but ACE protein in S3 remained. Deletion of ACE in S1 and S2 of PTCs did not change hypercholesterolemia-induced atherosclerosis in the ascending and aortic arch regions (PTC-ACE +/+ vs. PTC-ACE -/- : 9.6 ± 0.9% vs. 7.0 ± 1.9%; P = 0.13 by Mann-Whitney Rank Sum Test), as measured using an en face method. Conclusion: ACE deficiency in S1 and S2 of renal proximal tubular cells had no effect on atherosclerosis in hypercholesterolemic mice. Since ACE is more abundant in S3 than in S1 and S2 of PTCs, it would be important to determine the role of ACE in the S3 segment.

Iliosacral screw corridors in Japanese subjects: a study using reconstruction CT scans.

Objectives:To investigate the characteristics of iliosacral (IS) screw corridors of Japanese pelves.Methods:Computer tomography images of 42 adult Japanese subjects without any pelvic injury were analyzed at a workstation. Using the manual reconstruction function, the width of a simulated horizontal corridor for an IS screw on the true coronal and true axial planes in the upper (S1), second (S2), and the third (S3) sacral segments was measured. For pelves without an adequate S1 corridor, a cranially tilted corridor was sought. A corridor was defined as “adequate” if its width on both planes was 10 mm or more.Results:An adequate horizontal corridor was found in S1 in 17 (40.5%) subjects, in S2 in 29 (69.0%) subjects, and in S3 in no subject. An independent factor affecting the adequacy of the S1 corridor was the adequacy of the S2 corridor (OR: 0.09). Similarly, an independent factor affecting S2 adequacy was S1 adequacy (OR: 0.10). A tilted, 10 mm diameter corridor was found in all 25 subjects who did not have an adequate horizontal corridor in the S1 segment. The angle required to obtain a 10 mm diameter corridor inversely correlated with the diameter of a horizontal corridor on the true coronal plane (R = −0.713, P = .000).Conclusions:The characteristics of IS screw corridors in the 42 Japanese subjects were similar to those reported in previous studies conducted in the West. The importance of preoperative planning using reliable techniques, such as three-dimensional reconstruction, should be emphasized.Level of evidence: Diagnostic Level III. See Instructions for Authors for a complete description of level of evidence.

Open-state structure and pore gating mechanism of the cardiac sodium channel

The heartbeat is initiated by voltage-gated sodium channel NaV1.5, which opens rapidly and triggers the cardiac action potential; however, the structural basis for pore opening remains unknown. Here, we blocked fast inactivation with a mutation and captured the elusive open-state structure. The fast inactivation gate moves away from its receptor, allowing asymmetric opening of pore-lining S6 segments, which bend and rotate at their intracellular ends to dilate the activation gate to ∼10Å diameter. Molecular dynamics analyses predict physiological rates of Na+ conductance. The open-state pore blocker propafenone binds in a high-affinity pose, and drug-access pathways are revealed through the open activation gate and fenestrations. Comparison with mutagenesis results provides a structural map of arrhythmia mutations that target the activation and fast inactivation gates. These results give atomic-level insights into molecular events that underlie generation of the action potential, open-state drug block, and fast inactivation of cardiac sodium channels, which initiate the heartbeat.