S4 Segment Research Articles

Isoleucine gate blocks K+ conduction in C-type inactivation.

Many voltage-gated potassium (Kv) channels display a time-dependent phenomenon called C-type inactivation, whereby prolonged activation by voltage leads to the inhibition of ionic conduction, a process that involves a conformational change at the selectivity filter toward a non-conductive state. Recently, a high-resolution structure of a strongly inactivated triple-mutant channel kv1.2-kv2.1-3m revealed a novel conformation of the selectivity filter that is dilated at its outer end, distinct from the well-characterized conductive state. While the experimental structure was interpreted as the elusive non-conductive state, our molecular dynamics simulations and electrophysiological measurements show that the dilated filter of kv1.2-kv2.1-3m is conductive and, as such, cannot completely account for the inactivation of the channel observed in the structural experiments. The simulation shows that an additional conformational change, implicating isoleucine residues at position 398 along the pore lining segment S6, is required to effectively block ion conduction. The I398 residues from the four subunits act as a state-dependent hydrophobic gate located immediately beneath the selectivity filter. By mutating I398 to Asparagine, ion permeation can be resumed in the kv1.2-kv2.1-3m channel, which was not a reversion C-type inactivation, since AgTxII fails to block the ionic permeation of kv1.2-kv2.1-3m_I398N. As a critical piece of the C-type inactivation machinery, this structural feature is the potential target of a broad class of QA blockers and negatively charged activators thus opening new research directions towards the development of drugs that specifically modulate gating-states of Kv channels.

Novel Expression of Apical Bile Acid Transport (ASBT) More Proximally Than Distal Ileum Contributing to Enhanced Intestinal Bile Acid Absorption in Obesity.

Dietary lipid absorption is facilitated by bile acids. In the Zucker rat (ZR) model of obesity, bile acid absorption, mediated by the apical sodium bile acid transporter (ASBT), was increased in villus cells from the distal ileum. However, whether ASBT may be de novo expressed more proximally in the small intestine during obesity to facilitate additional bile acid absorption is not known. For this, starting from the end of the ileum to the mid jejunum, caudal-orally, five intestinal segments of equal length (S1-S5) were separated from lean and obese ZRs (LZR and OZR). Intestinal mucosa obtained from these segments were used for total RNA extraction, RT-qPCR and 3H-TCA uptake. The results showed that bile acid absorption along with the mRNA expression of ASBT and FXR progressively decreased caudal-orally in both LZRs and OZRs but was significantly higher in all small intestinal segments in OZRs. The expression of GATA4 was absent in the distal ileum (S1) in both LZRs and OZRs, but steadily increased along the proximal length in both. However, this steady increase was significantly reduced in the comparative obese proximal intestinal segments S2, S3, S4 and S5. The expressions of bile acid-activated G-protein-coupled bile acid receptor TGR5 and S1PR2 were unaltered in segments S1-S4 but were significantly increased in OZR S5. The paradigm changing observation of this study is that ASBT is expressed more proximally in the small intestine in obesity. This likely increases overall bile acid absorption and thereby lipid absorption in the proximal small intestine in obesity.

Risk Factors for Locoregional Relapse After Segmentectomy: Supplementary Analysis of the JCOG0802/WJOG4607L Trial

IntroductionThe JCOG0802/WJOG4607L trial revealed superior overall survival in segmentectomy compared with lobectomy for small-peripheral NSCLC. Nevertheless, locoregional relapse (LR) is a major issue for segmentectomy. An ad hoc supplementary analysis aimed to determine the risk factors for LR and the degree of advantages of segmentectomy on the basis of primary tumor sites. MethodsParticipants in multi-institutional and intergroup, open-label, phase 3 randomized controlled trial in Japan were enrolled from August 10, 2009, to October 21, 2014. Risk factors for LR after segmentectomy and clinical features following the primary tumor site were investigated. ResultsOf 1105 patients, 576 and 529 underwent lobectomy and segmentectomy, respectively. The primary tumor site for segmentectomy was the left upper division, left lingular segment, left S6, left basal segment, right upper lobe, right S6, or right basal segment. Multivariable analysis in the segmentectomy group revealed that pure-solid appearance on thin-section computed tomography (OR = 3.230; 95% confidence interval [CI]: 1.559–6.690; p = 0.0016), margin distance less than the tumor size (OR = 2.682; 95% CI: 1.350–5.331; p = 0.0049), and male sex (OR = 2.089; 95% CI: 1.047–4.169; p = 0.0366) were significantly associated with LR. Patients with left lingular segment tumors (OR = 4.815; 95% CI: 1.580–14.672) tended to experience LR more frequently than those with left upper division tumors, although primary tumor sites were not statistically significant. ConclusionsThin-section computed tomography findings and margin distance are important factors to avoid LR in segmentectomy.

An Intelligent Mobile Search System

This article is devoted to the development of an intelligent mobile system used for humanitarian demining. At the same time, the problems of detection, localization and storage of the obtained data are solved. The system operation is based on the use of a synthetic aperture ground penetrating radar, which makes it possible to detect mines both on the earth's surface and underground. A quadcopter is used as a carrier. A set of technical means has been developed. The central and graphic processors are used as a processing unit. Intelligent elements for processing the obtained data are convolutional neural networks, for machine learning of which a synthetic dataset was used. The data is organized into S3 segments based on various parameters, such as date, location and sensor type. This organization facilitates data retrieval and management. Data is encrypted both during transmission and at rest using AWS Key Management Service to ensure confidentiality.

Characterization of a mammalian orthoreovirus isolated from the large flying fox, Pteropus vampyrus, in Indonesia.

Fruit bats serve as an important reservoir for many zoonotic pathogens, including Nipah virus, Hendra virus, Marburg virus and Lyssavirus. To gain a deeper insight into the virological characteristics, pathogenicity and zoonotic potential of bat-borne viruses, recovery of infectious viruses from field samples is important. Here, we report the isolation and characterization of a mammalian orthoreovirus (MRV) from a large flying fox (Pteropus vampyrus) in Indonesia, which is the first detection of MRV in Southeast Asia. MRV was recovered from faecal samples of three different P. vampyrus in Central Java. Nucleotide sequence analysis revealed that the genome of the three MRV isolates shared more than 99% nucleotide sequence identity. We tentatively named one isolated strain as MRV12-52 for further analysis and characterization. Among 10 genome segments, MRV12-52 S1 and S4, which encode the cell-attachment protein and outer capsid protein, had 93.6 and 95.1% nucleotide sequence identities with known MRV strains, respectively. Meanwhile, the remaining genome segments of MRV12-52 were divergent with 72.9-80.7 % nucleotide sequence identities. Based on the nucleotide sequence of the S1 segment, MRV12-52 was grouped into serotype 2, and phylogenetic analysis demonstrated evidence of past reassortment events. In vitro characterization of MRV12-52 showed that the virus efficiently replicated in BHK-21, HEK293T and A549 cells. In addition, experimental infection of laboratory mice with MRV12-52 caused severe pneumonia with 75% mortality. This study highlights the presence of pathogenic MRV in Indonesia, which could serve as a potential animal and public health concern.

Dual role of the S5 segment in type 1 ryanodine receptor channel gating

The type 1 ryanodine receptor (RyR1) is a Ca2+ release channel in the sarcoplasmic reticulum that is essential for skeletal muscle contraction. RyR1 forms a channel with six transmembrane segments, in which S5 is the fifth segment and is thought to contribute to pore formation. However, its role in channel gating remains unclear. Here, we performed a functional analysis of several disease-associated mutations in S5 and interpreted the results with respect to the published RyR1 structures to identify potential interactions associated with the mutant phenotypes. We demonstrate that S5 plays a dual role in channel gating: the cytoplasmic side interacts with S6 to reduce the channel activity, whereas the luminal side forms a rigid structural base necessary for S6 displacement in channel opening. These results deepen our understanding of the molecular mechanisms of RyR1 channel gating and provide insight into the divergent disease phenotypes caused by mutations in S5.

Atomistic mechanisms of the regulation of small-conductance Ca2+-activated K+ channel (SK2) by PIP2

Small-conductance Ca2+-activated K+ channels (SK, KCa2) are gated solely by intracellular microdomain Ca2+. The channel has emerged as a therapeutic target for cardiac arrhythmias. Calmodulin (CaM) interacts with the CaM binding domain (CaMBD) of the SK channels, serving as the obligatory Ca2+ sensor to gate the channels. In heterologous expression systems, phosphatidylinositol 4,5-bisphosphate (PIP2) coordinates with CaM in regulating SK channels. However, the roles and mechanisms of PIP2 in regulating SK channels in cardiomyocytes remain unknown. Here, optogenetics, magnetic nanoparticles, combined with Rosetta structural modeling, and molecular dynamics (MD) simulations revealed the atomistic mechanisms of how PIP2 works in concert with Ca2+-CaM in the SK channel activation. Our computational study affords evidence for the critical role of the amino acid residue R395 in the S6 transmembrane segment, which is localized in propinquity to the intracellular hydrophobic gate. This residue forms a salt bridge with residue E398 in the S6 transmembrane segment from the adjacent subunit. Both R395 and E398 are conserved in all known isoforms of SK channels. Our findings suggest that the binding of PIP2 to R395 residue disrupts the R395:E398 salt bridge, increasing the flexibility of the transmembrane segment S6 and the activation of the channel. Importantly, our findings serve as a platform for testing of structural-based drug designs for therapeutic inhibitors and activators of the SK channel family. The study is timely since inhibitors of SK channels are currently in clinical trials to treat atrial arrhythmias.

Hemangioendothelioma of the spleen and liver in a 1-year-old child.

Concurrent occurrence of hemangioendothelioma in the spleen and liver of a 1-year-old child is a rare clinical case.She had a history of good health. Laboratory tests showed elevated inflammatory markers, but all other parameters were within normal range.In this article, we exhibit the typical clinical presentation and Pathology imaging features of this disease.CT imaging revealed a 9.8 cm×8.6 cm mass in the spleen, with areas of non-enhancing liquefactive necrosis. The mass exhibited heterogeneous enhancement during the arterial phase and progressive enhancement during the venous phase. Multiple nodules were observed in liver segments S2 and S4, the largest being approximately 3.7 cm×3.5 mm, with enhancement patterns similar to the splenic lesion. The patient underwent splenectomy, left hemihepatectomy, and cholecystectomy. Intraoperatively, the splenic mass exhibited some areas appearing spongy. Multiple nodules were observed in the left liver, presenting as gray-brown solid masses with a spongy texture. Pathology confirmed a diagnosis of hemangioendothelioma, supported by positive immunohistochemical staining for CD31, CD34, ERG, and FLI-1.

Abstract P391: Role of Renal Dopamine D2 Receptor in Inverse Salt Sensitivity and Salt Sensitivity of Blood Pressure: Insights from Nephron Segment-Specific Deletion Models

The renal dopamine D2 receptor (D2R) is essential in renal and blood pressure (BP) homeostasis. In mice, global Drd2 deletion or renal-selective Drd2 silencing increases the renal expression of proinflammatory factors, renal injury markers, and BP. The D2R is expressed in several nephron segments, including the proximal and distal convoluted tubules. To study the differential effects of D2R in these segments, we generated two mouse models: one with Drd2 deletion only in the S1 and S2 segments of the proximal tubule P SGLT2 ::Cre+ Drd2 fl/fl ( Sglt2 cKO ) and their littermates as controls, P SGLT2 ::Cre- Drd2 fl/fl (Sglt2 WT) and another with deletion of the receptor in the whole nephron P CDHR16 ::Cre+ Drd2 fl/fl ( Cdhr16 cKO ) and their littermates as controls, P CDHR16 ::Cre- Drd2 fl/fl (Cdhr16 WT). In male Sglt2 cKO mice, compared with Sglt2 WT mice, D2R expression in the renal cortex was decreased by 25% (P<0.05, n=5-6/group). In Cdhr16 cKO mice, compared with Cdhr16 WT mice, D2R expression was decreased by 30% (P<0.05; n=3/group). In Sglt2 cKO mice, tubular lumen expansion, an indication of tubular damage, was higher on low salt (0.09%NaCl; LS) than on normal salt (0.4%NaCl; NS) (25.5±.8 vs. 11.4±.0.3; P<0.001) diet. In Cdhr16 cKO mice tubular lumen expansion was also higher on LS than NS (13.9±0.4 vs 8.7±0.2; P<0.001) diet. In Sglt2 cKO mice, BP (carotid artery under anesthesia) was higher on LS (130±2 mm Hg) than on NS (107±2 mm Hg) or HS (4% NaCl) (100±3 mm Hg) (n=10/group) (P<0.05) diet. In Cdhr16 cKO mice, BP (tail cuff, CODA under anesthesia, confirmed by telemetry) was higher on LS (110±8 mm Hg, P<0.02; n=4-5/group) and HS (119±9 mm Hg, P<0.05; n=4/group) diets than on NS diet (84±5 mmHg). On LS diet, UNaV was lower in Sglt2 cKO than Sglt2 WT (1±0.3 vs 7±2 µEq/24h; P< 0.05; n=4-6/group) mice. On LS diet, UNaV was also lower in Cdhr16 cKO than Cdhr16 WT (5±0.9 vs 34±14 µEq/24h; P<0.05; n=3-4/group) mice. These results indicate that a decrease in D2R expression only in the proximal tubule results in inverse salt sensitivity of BP, i.e., BP higher on LS than NS or HS diets, while downregulation of its expression in the whole nephron results in inverse salt sensitivity, as well as salt sensitivity.

Identification of multiple inter- and intra-genotype reassortment mammalian orthoreoviruses from Japanese black cattle in a beef cattle farm

Mammalian orthoreoviruses (MRVs), belonging to the genus Orthoreovirus in the family Spinareoviridae, possess a double-stranded RNA segmented genome. Due to the segmented nature of their genome, MRVs are prone to gene reassortment, which allows for evolutionary diversification. Recently, a genotyping system for each MRV gene segment was proposed based on nucleotide differences. In the present study, MRVs were isolated from the fecal samples of Japanese Black cattle kept on a farm in Japan. Complete genome sequencing and analysis of 41 MRV isolates revealed that these MRVs shared almost identical sequences in the L1, L2, L3, S3, and S4 gene segments, while two different sequences were found in the S1, M1, M2, M3, and S2 gene segments. By plaque cloning, at least six genetic constellation patterns were identified, indicating the occurrence of multiple inter- (S1 and M2) and intra- (M1, M3, and S2) reassortment events. This paper represents the first report describing multiple reassortant MRVs on a single cattle farm. These MRV gene segments exhibited sequence similarity to those of MRVs isolated from cattle in the U.S. and China, rather than to MRVs previously isolated in Japan. Genotypes consisting solely of bovine MRVs were observed in the L1, M1, and M2 segments, suggesting that they might have evolved within the cattle population.

Urinary GM2AP coincides with renal cortical damage and grades cisplatin nephrotoxicity severity in rats

Nephrotoxicity, including electrolytic disorders and acute kidney injury (AKI), limits the clinical dosage and utility of platinated antineoplastics such as cisplatin. Cisplatin nephrotoxicity embodies a tubulopathy involving the medullary S2 and S3 segments of the proximal and the distal tubules. Higher dosage extends damage over the cortical S1 segment and intensifies overall injury. However, the standard diagnosis based on plasma creatinine as well as novel injury biomarkers lacks enough pathophysiological specificity. Further granularity in the detection of renal injury would help understand the implications of individual damage patterns needed for personalized patient handling. In this article, we studied the association of urinary ganglioside GM2 activator protein (GM2AP) with the patterns of tubular damage produced by 5 and 10 mg/kg cisplatin in rats. Our results show that GM2AP appears in the urine only following damage to the cortical segment of the proximal tubule. The information provided by GM2AP is not redundant with but distinct and complementary to that provided by urinary neutrophil gelatinase-associated lipocalin (NGAL). Similarly, treatment with 150 mg/kg/day gentamicin damages the renal cortex and increases GM2AP urinary excretion; whereas renal ischemia, which does not affect the cortex, has no effect on GM2AP. Because of the key role of the cortical proximal tubule in renal function, we contend GM2AP as a potential diagnostic biomarker to stratify AKI patients according to the underlying damage and follow their evolution and prognosis. Prospectively, urinary GM2AP may help grade the severity of platinated antineoplastic nephrotoxicity by forming part of a non-invasive liquid biopsy.

Fully Endoscopic Transforaminal Approach for L5–S1 Foraminal Stenosis: A Narrative Review

Lumbar foraminal stenosis (LFS) is a fairly common degenerative condition of the spine that can often occur in the L5–S1 segment. Traditional surgical approaches for LFS can be categorized into microscopic foraminotomy via the Wiltse approach and interbody fusion. Microscopic foraminotomy via the Wiltse approach was previously considered the gold standard for treating LFS. However, with advancements in endoscopic equipment and techniques, fully endoscopic foraminotomy through various approaches is now widely performed for the treatment of LFS. Among these approaches, endoscopic foraminotomy via the transforaminal approach offers many advantages, but difficulties may be encountered when there are anatomical barriers, which are often present in the L5–S1 segment. This study aimed to explore the overall clinical outcomes and complications of transforaminal endoscopic lumbar foraminotomy, as well as the challenges specific to the L5–S1 segment and techniques to overcome them.

Experimental research on PPF anti-cracking effect in scale model of hollow rigid frame bridge

The hollow rigid frame bridge has many advantages, such as being lightweight, having strong spanning ability, and having slight deflection in span. This type of bridge has a broad potential for application in regions of many canyons and hills. While there has been less research into the application of this type of bridge, some of the bridges in early service have cracking problems. To satisfy the demand for cracking resistance of the Yunnanzhuang large-span hollow rigid frame bridge, our group proposed using Polypropylene Fibers (PPF) to enhance the strength of concrete against cracking. After analyzing the structure of the whole bridge, we gave the critical sections of the bridge and carried out a series of tests to give the PPF dosage that applies to the project. This paper focuses on the use of reduced-size bridge model tests to investigate the effect of PPF on the cracking resistance of hollow rigid frame bridges under bending.In this paper, the similarity criterion between the actual bridge and the model was calculated by the method of magnitude analysis, according to which scale-down model beams of the upper chord S4 segment and mid-span jointing segment of Yunnanzhuang Bridge were designed under the geometry of 1:5. We respectively made these models using the same C55 concrete as the actual bridge and Polypropylene Fibre Reinforced Concrete (PPFRC) with 0.3 % volumetric admixture of PPF in the same mix ratio, and three-point bending static load tests were performed on these models. To make up for the insufficiency of test groups, we performed a finite element analysis using ABAQUS and the CDP constitution, which led us to some reliable conclusions.Considering that concrete materials have size effect, directly using the results of model tests to predict the cracking stresses of the actual bridge is not accurate. In this paper, some theories on size effects were examined. Finally, the Size Effect Model (SEM), Boundary Effects Model (BEM), and Weibull's brittle strength theory were selected to correct the test results.The results show that PPF can increase the cracking load of the test beams, ranging from 11.22 % to 13.49 %. After using selected size effect theories to predict the cracking stresses in actual bridges, the results show that PPF can enhance the cracking strength of C55 concrete, with an increase ranging from 9.15 % to 18.75 %. Combined with the results of the structural analysis of the whole bridge, the critical section has a cracking stress between 2.6 MPa and 3.5 MPa when using C55 concrete, which has a certain risk of cracking. However, when using PPFRC, the cracking stress ranges from 3.1 MPa to 4.2 MPa, with no risk of cracking in most unfavorable cases, which can satisfy the demand for concrete cracking resistance of Yunnanzhuang Bridge.

Urologic Morbidity in Surgery of Placenta Accreta Spectrum in Universitas Andalas Hospital

Background: Hysterectomy for placenta accreta spectrum disorders is known to be associated with urologic morbidity, including intentional or unintentional cystostomy, ureteral injury, and bladder fistula. Case: A 32year old woman with urine retention post total hysterectomy on indications placenta accreta spectrum Grade 3 type 4 S2 segment- 9 days ago, referred to Universitas Andalas Hospital. The patient complained difficulty to urinate, hematuria and supra pubic pain. Physical examination sign of acute abdomen unclear. A Pelvic abdominal ultrasound was performed, the result were Acites and complex acites, left renal hydronefrosis, cystitis and sludge gallblader. From the laboratory result found anemia, leucocytosis, trombositosis, ureum, creatinine and albumin were in normal limit, hyponatremia, hypokalemia, hypocalsemia. The patient were given antibiotics, blood transfusion and natrium, kalium and calcium correction. Cystoscopy was performed to explore the bladder, the result were found adhesion and ruptured at the posterior wall of the bladder a long 3 cm then proceed with laparotomy to repair the bladder and adhesiolisis. During hospitalization, the patient’s condition was good, hemodynamics was stable with sufficient diuresis. The patient was discharged on day 4 after laparotomy of bladder repair with temporary urine catheter installed. Discussion: This patient diagnose previously is placenta accreta spectrum with percreta graded so had a high risk of urologic morbidity. The bladder ruptured occurred after 9th day of hysterectomy. This can occur because the injury during dissection of the uterine vesicular fold undergoes necrosis and then become opens on the 9th day after hysterectomy. A multidisciplinary team should be made in management of placenta accreta spectrum. A team comprising a consultant maternal fetal medicine with pelvic surgery experienced, a blood bank team, an anesthesiologist, a urologist skilled, an interventional radiologist and an experienced neonatologist is advised. Keywords: urologic complication, placenta accreta, urologic morbidity

Biophysical Analysis of a Minimalistic Kidney Model Expressing SGLT1 Reveals Crosstalk between Luminal and Lateral Membranes and a Plausible Mechanism of Isosmotic Transport.

We extended our model of the S1 tubular segment to address the mechanisms by which SGLT1 interacts with lateral Na/K pumps and tight junctional complexes to generate isosmotic fluid reabsorption via tubular segment S3. The strategy applied allowed for simulation of laboratory experiments. Reproducing known experimental results constrained the range of acceptable model outputs and contributed to minimizing the free parameter space. (1) In experimental conditions, published Na and K concentrations of proximal kidney cells were found to deviate substantially from their normal physiological levels. Analysis of the mechanisms involved suggested insufficient oxygen supply as the cause and, indirectly, that a main function of the Na/H exchanger (NHE3) is to extrude protons stemming from mitochondrial energy metabolism. (2) The water path from the lumen to the peritubular space passed through aquaporins on the cell membrane and claudin-2 at paracellular tight junctions, with an additional contribution to water transport by the coupling of 1 glucose:2 Na:400 H2O in SGLT1. (3) A Na-uptake component passed through paracellular junctions via solvent drag in Na- and water-permeable claudin-2, thus bypassing the Na/K pump, in agreement with the findings of early studies. (4) Electrical crosstalk between apical rheogenic SGLT1 and lateral rheogenic Na/K pumps resulted in tight coupling of luminal glucose uptake and transepithelial water flow. (5) Isosmotic transport was achieved by Na-mediated ion recirculation at the peritubular membrane.

Comparison of Ropivacaine with or without Fentanyl in Spinal Anaesthesia for Lower Limb Surgeries

Introduction: Spinal anaesthesia is a preferred technique used for lower limb orthopaedic surgeries. Ropivacaine with its short duration of motor blockade and provision for early ambulation along with addition of spinal additives has proven beneficial to the patient. This prospective, double-blind, randomized controlled study set out to evaluate the effects of 0.75% isobaric ropivacaine with fentanyl versus 0.75% isobaric ropivacaine during lower limb orthopaedic surgeries performed under spinal anaesthesia. Methods: The study enrolled 74 patients, aged 18-65 years of either sex, ASA PS I and II, planned for lower limb orthopaedic surgeries. Patients were randomly allocated to receive either 2.5 ml of 0.75% isobaric ropivacaine and 0.5ml of normal saline (Group R) or 2.5 ml of 0.75% isobaric ropivacaine and 0.5ml of fentanyl (25mcg) (Group RF). Results: The demographic profile, onset time of sensory block to T10 dermatome, time for complete motor blockade, maximum block height, duration of motor block, and haemodynamic parameters did not significantly differ between the two groups. Group R took 200.27 ± 21.28 minutes for the S2 dermatome segment regression, while Group RF took 284.59 ± 32.88 minutes (p-value<0.001). Group RF experienced analgesia for a longer duration (335.68±22.18 min) than Group R (240.00±28.28 min) (p-value<0.001). Conclusion: Fentanyl greatly extends the duration of S2 segment regression and analgesia when combined with ropivacaine; the effects on haemodynamics and motor blockade is clinically negligible and side effects are minimal.

A case of lung metastasis from gastric cancer presenting as ground-glass opacity dominant nodules

BackgroundMost metastatic lung tumors present as solid nodules on chest computed tomography (CT). In contrast, ground-glass opacity on chest computed tomography usually suggests low-grade malignant lesions such as adenocarcinoma in situ or atypical adenomatous hyperplasia of the lung.Case presentationA 75-year-old woman with a history of gastric cancer surgery approximately 5 years prior was referred to the Department of Thoracic Surgery at our hospital because of two newly appearing pulmonary ground-glass opacity-dominant nodules on chest computed tomography. She had two ground-glass opacities in the right lower lobe, one in the S6 segment was 12 mm and the other in the S10 segment was 8 mm. On chest computed tomography 15 months prior to referral, the lesion in the S6 segment was 8 mm, and the lesion in the S10 segment was 2 mm. She was suspected to have primary lung cancer and underwent wide-wedge resection of the nodule in the S6 segment. In the resected specimen, polygonal tumor cells infiltrated the alveolar septa, with some tumor cells exhibiting signet ring cell morphology. Based on morphological similarities to the tumor cells of previous gastric cancers and the results of immunostaining, the patient was diagnosed with lung metastases of gastric cancer.ConclusionsPulmonary nodules in patients with a history of cancer in other organs, even if ground-glass opacity is predominant, should also be considered for the possibility of metastatic pulmonary tumors if they are growing rapidly.

Peptides Derived from the SARS-CoV-2 S2-Protein Heptad-Repeat-2 Inhibit Pseudoviral Fusion at Micromolar Concentrations: The Role of Palmitic Acid Conjugation.

SARS-CoV-2 S-protein-mediated fusion is thought to involve the interaction of the membrane-distal or N-terminal heptad repeat (NHR) ("HR1") of the cleaved S2 segment of the protein and the membrane-proximal or C-terminal heptad repeat (CHR) ("HR2") regions of the protein. We examined the fusion inhibitory activity of a PEGylated HR2-derived peptide and its palmitoylated derivative using a pseudovirus infection assay. The latter peptide caused a 76% reduction in fusion activity at 10 µM. Our results suggest that small variations in peptide derivatization and differences in the membrane composition of pseudovirus preparations may affect the inhibitory potency of HR2-derived peptides. We suggest that future studies on the inhibition of infectivity of SARS-CoV-2 in both in vitro and in vivo systems consider the need for higher concentrations of peptide inhibitors.

Ferroptosis is involved in cisplatin sensitivity of the S3 segment of immortalized proximal tubule cells

Cisplatin (CDDP) is administered as an anticancer drug across a broad spectrum of cancer treatments, but it causes severe renal damage. Several studies have attempted to elucidate the cause of CDDP-induced renal injury, but the detailed mechanism remains unclear. We previously found that S3 cells are more sensitive to CDDP than S1 and S2 cells by using immortalized cells derived from S1, S2, and S3 segments of proximal tubules. In this study, we investigated the potential contribution of reactive oxygen species (ROS) to the sensitivity of S3 cells to CDDP. The results showed that S3 cells have high sensitivity to CDDP, paraquat (PQ) and three ROS substances. To examine the mechanisms underlying the sensitivity to ROS in S3 cells, we compared the cellular responses of CDDP- and PQ-exposed S3 cells. The results indicated that the levels of intracellular ROS and lipid peroxides were increased in S3 cells after CDDP and PQ exposure. The intracellular levels of antioxidant proteins such as thioredoxin, thioredoxin reductase 1 and glutathione peroxidase 4 were also increased by exposure to PQ, but these proteins were decreased by CDDP exposure in S3 cells. Furthermore, the levels of intracellular free Fe2+ were increased by CDDP exposure only in S3 cells but not S1 or S2 cells, and cytotoxicity by exposure to CDDP in S3 cells was suppressed by ferroptosis inhibitors. These results suggested that the induction of ferroptosis due to the ROS production through attenuation of the antioxidant system and elevated free Fe2+ is partly responsible for the sensitivity of S3 cells to CDDP.

#2858 Immunohistochemical study reveals increased GLUT1 expression in proximal tubules of patients with acute interstitial nephritis

Abstract Background and Aims Interstitial inflammation in acute interstitial nephritis can advance into tubular epithelial cells and produce proximal tubular dysfunction, which may be clinically expressed as renal glycosuria. Previous studies have shown that the presence of renal glycosuria in acute kidney injury is a diagnostic clue for acute interstitial nephritis (AIN) with an excellent specificity. Sodium-independent glucose transporter 1 (GLUT1) is localized in the basolateral membrane of epithelial cells along the entire length of the proximal tubule, mainly in the S3 segment, and it is involved in the transcellular glucose transport. The aim of this study was to examine renal expression of GLUT1 in the proximal tubules of patients with biopsy-proven AIN. Method We identified patients with biopsy-proven AIN. After excluding patients with diabetes mellitus and patients who had received steroid treatment previous to the kidney biopsy, we selected 10 patients with biopsy-proven AIN, and we selected 10 patients with acute tubular necrosis (ATN) matched for age, proteinuria and glomerular filtration rate as the control group. An immunohistochemical study for GLUT1 was performed on the biopsies of patients with AIN and ATN. Staining intensity was graded as 0 (negative), 1+ (weak), 2+ (moderate), and 3+ (strong). GLUT1 expression was defined as focal when <50% of epithelial cells stained positive, and diffuse when >50% of the tissue showed strong staining. Results Renal glycosuria was present in 60% of the selected patients with AIN, with a median glycosuria of 150 mg/dl (IQR 0-162 mg/dl), while only 1 patient (10%) with ATN presented glycosuria (p = 0.037). All patients with AIN showed moderate or strong cytoplasmic GLUT1 staining in the epithelial cells of proximal tubules, which was significantly more intense (2+; 20% vs 11%, 3+; 80% vs 33.3%, p = 0.008) and diffuse (80% vs 22.2%, p = 0.002) than in patients with ATN. There was a tendency for positive correlation between the concentration of glycosuria and the extension of GLUT1 staining (r = 0.316, p = 0.078). Conclusion We found higher expression of GLUT1 in the cytoplasm of proximal tubular cells in patients with AIN in comparison to ATN. These findings suggest that proximal tubular injury plays a key role in the pathogenesis of AIN, leading to renal glycosuria in some cases. We hypothesize that the localization of strong GLUT1 staining in the cytoplasm of proximal tubular cells may indicate a misallocation of GLUT1 from plasma membrane where it is functional and a reversed cell polarity which might account for the observed renal glycosuria.