Cellular senescence induction leads to progressive cell death via the INK4a-RB pathway in naked mole-rats.

Naked mole-rats (NMRs) have exceptional longevity and are resistant to age-related physiological decline and diseases. Given the role of cellular senescence in aging, we postulated that NMRs possess unidentified species-specific mechanisms to prevent senescent cell accumulation. Here, we show that upon induction of cellular senescence, NMR fibroblasts underwent delayed and progressive cell death that required activation of the INK4a-retinoblastoma protein (RB) pathway (termed "INK4a-RB cell death"), a phenomenon not observed in mouse fibroblasts. Naked mole-rat fibroblasts uniquely accumulated serotonin and were inherently vulnerable to hydrogen peroxide (H2 O2 ). After activation of the INK4a-RB pathway, NMR fibroblasts increased monoamine oxidase levels, leading to serotonin oxidization and H2 O2 production, which resulted in increased intracellular oxidative damage and cell death activation. In the NMR lung, induction of cellular senescence caused delayed, progressive cell death mediated by monoamine oxidase activation, thereby preventing senescent cell accumulation, consistent with in vitro results. The present findings indicate that INK4a-RB cell death likely functions as a natural senolytic mechanism in NMRs, providing an evolutionary rationale for senescent cell removal as a strategy to resist aging.

Impact of Reinfection with SARS-CoV-2 Omicron Variants in Previously Infected Hamsters.

The diversity of SARS-CoV-2 mutations raises the possibility of reinfection of individuals previously infected with earlier variants, and this risk is further increased by the emergence of the B.1.1.529 Omicron variant. In this study, we used an in vivo, hamster infection model to assess the potential for individuals previously infected with SARS-CoV-2 to be reinfected with Omicron variant and we also investigated the pathology associated with such infections. Initially, Syrian hamsters were inoculated with a lineage A, B.1.1.7, B.1.351, B.1.617.2 or a subvariant of Omicron, BA.1 strain and then reinfected with the BA.1 strain 5 weeks later. Subsequently, the impact of reinfection with Omicron subvariants (BA.1 and BA.2) in individuals previously infected with the BA.1 strain was examined. Although viral infection and replication were suppressed in both the upper and lower airways, following reinfection, virus-associated RNA was detected in the airways of most hamsters. Viral replication was more strongly suppressed in the lower respiratory tract than in the upper respiratory tract. Consistent amino acid substitutions were observed in the upper respiratory tract of infected hamsters after primary infection with variant BA.1, whereas diverse mutations appeared in hamsters reinfected with the same variant. Histopathology showed no acute pneumonia or disease enhancement in any of the reinfection groups and, in addition, the expression of inflammatory cytokines and chemokines in the airways of reinfected animals was only mildly elevated. These findings are important for understanding the risk of reinfection with new variants of SARS-CoV-2. IMPORTANCE The emergence of SARS-CoV-2 variants and the widespread use of COVID-19 vaccines has resulted in individual differences in immune status against SARS-CoV-2. A decay in immunity over time and the emergence of variants that partially evade the immune response can also lead to reinfection. In this study, we demonstrated that, in hamsters, immunity acquired following primary infection with previous SARS-CoV-2 variants was effective in preventing the onset of pneumonia after reinfection with the Omicron variant. However, viral infection and multiplication in the upper respiratory tract were still observed after reinfection. We also showed that more diverse nonsynonymous mutations appeared in the upper respiratory tract of reinfected hamsters that had acquired immunity from primary infection. This hamster model reveals the within-host evolution of SARS-CoV-2 and its pathology after reinfection, and provides important information for countermeasures against diversifying SARS-CoV-2 variants.

SARS-CoV-2 ORF8 is a viral cytokine regulating immune responses.

Many patients with severe COVID-19 suffer from pneumonia and the elucidation of the mechanisms underlying the development of this severe condition is important. The in vivo function of the ORF8 protein secreted by SARS-CoV-2 is not well understood. Here, we analyzed the function of ORF8 protein by generating ORF8-knockout SARS-CoV-2 and found that the lung inflammation observed in wild-type SARS-CoV-2-infected hamsters was decreased in ORF8-knockout SARS-CoV-2-infected hamsters. Administration of recombinant ORF8 protein to hamsters also induced lymphocyte infiltration into the lungs. Similar pro-inflammatory cytokine production was observed in primary human monocytes treated with recombinant ORF8 protein. Furthermore, we demonstrated that the serum ORF8 protein levels are well-correlated with clinical markers of inflammation. These results demonstrated that the ORF8 protein is a SARS-CoV-2 viral cytokine involved in the immune dysregulation observed in COVID-19 patients, and that the ORF8 protein could be a novel therapeutic target in severe COVID-19 patients.

Prednisolone improves hippocampal regeneration after trimethyltin-induced neurodegeneration in association with prevention of T lymphocyte infiltration.

The endogenous regenerative capacity of the brain is quite weak; however, a regenerative reaction, the production of new neurons (neurogenesis), has been reported to occur in brain lesions. In addition, leukocytes are well known to infiltrate brain lesions. Therefore, leukocytes would also have a link with regenerative neurogenesis; however, their role has not been fully elucidated. In this study, we investigated leukocyte infiltration and its influence on brain tissue regeneration in a trimethyltin (TMT)-injected mouse model of hippocampal regeneration. Immunohistochemically, CD3-positive T lymphocytes were found in the hippocampal lesion of TMT-injected mice. Prednisolone (PSL) treatment inhibited T lymphocyte infiltration and increased neuronal nuclei (NeuN)-positive mature neurons and doublecortin (DCX)-positive immature neurons in the hippocampus. Investigation of bromodeoxyuridine (BrdU)-labeled newborn cells revealed the percentage of BrdU/NeuN- and BrdU/DCX-positive cells increased by PSL treatment. These results indicate that infiltrated T lymphocytes prevent brain tissue regeneration by inhibiting hippocampal neurogenesis.

Hepatitis C virus modulates signal peptide peptidase to alter host protein processing.

Immunoevasins are viral proteins that prevent antigen presentation on major histocompatibility complex (MHC) class I, thus evading host immune recognition. Hepatitis C virus (HCV) evades immune surveillance to induce chronic infection; however, how HCV-infected hepatocytes affect immune cells and evade immune recognition remains unclear. Herein, we demonstrate that HCV core protein functions as an immunoevasin. Its expression interfered with the maturation of MHC class I molecules catalyzed by the signal peptide peptidase (SPP) and induced their degradation via HMG-CoA reductase degradation 1 homolog, thereby impairing antigen presentation to CD8+ T cells. The expression of MHC class I in the livers of HCV core transgenic mice and chronic hepatitis C patients was impaired but was restored in patients achieving sustained virological response. Finally, we show that the human cytomegalovirus US2 protein, possessing a transmembrane region structurally similar to the HCV core protein, targets SPP to impair MHC class I molecule expression. Thus, SPP represents a potential target for the impairment of MHC class I molecules by DNA and RNA viruses.

Exploring feasibility criteria for stereotactic radiosurgical treatment of multiple brain metastases using five linac machines.

PURPOSE: This study aimed to find descriptors that correlates with normal brain dose to determine the feasibility of performing fractionated stereotactic radiosurgery (SRS) for multiple brain metastases (BMs) using five linac machines. METHODS: Thirty-two patients with 1-30 BMs were enrolled. Treatment plans were created using TrueBeam, Novalis Tx, TrueBeam Edge, Halcyon, and Tomotherapy linacs. The sum of all planning target volumes (PTVs) was defined as PTVall, and the brain region excluding PTVall was defined as normal brain. The total surface area (TSA) of the PTV was calculated from the sum of the surface areas of the equivalent spheres for each PTV. Volumes receiving more than 5, 12, and 18 Gy (V5Gy, V12Gy, and V18Gy, respectively) were used for evaluation of normal brain dose. Correlations between normal brain dose and each tumor characteristic (number, PTVall, and TSA) were investigated using the Spearman rank correlation coefficient. RESULTS: Correlations between each characteristic and normal brain dose were statistically significant (p < 0.05) across all machines. The correlation coefficients between each characteristic and V18Gy for the five machines were as follows: tumor number, 0.39-0.60; PTVall, 0.79-0.93; TSA, 0.93-0.99. The fit equations between TSA and V18Gy exhibited high coefficients of determination, ranging from 0.92 to 0.99 across five machines. CONCLUSION: This study devised fractionated SRS plans using for 1-30 BMs across five linac machines to find descriptors for determining SRS feasibility based on normal brain dose. TSA proved to be a promising descriptor of SRS feasibility for treating multiple BMs.

Chimeric flavivirus causes vascular leakage and bone marrow suppression in a mouse model.

Previously, we demonstrated the utility of a recombinant chimeric flavivirus (DV2ChimV), which carries the premembrane (prM) and envelope (E) genes of a type 2 DENV clinical (Thai) isolate on a backbone of Japanese encephalitis virus, for evaluating the protective efficacy of antidengue envelope antibodies both in vitro and in vivo. Here, to assess the potential use of this model for pathological studies, we aimed to characterize interferon-α/ß-γ-receptor double-knockout mice (IFN-α/ß/γR dKO mice) infected with DV2ChimV. Vascular leakage and bone marrow suppression are unique features of severe dengue. In the current model, DV2ChimV caused vascular leakage in the liver and intestine at the moribund stage. High levels of virus were detected in the bone marrow, and strong bone marrow suppression (i.e., disappearance of megakaryocytes and erythroblastic islets) was observed. These observations suggest that the DV2ChimV-infected mouse model mimics the vascular leakage and bone marrow suppression observed in human cases.

Disseminated histiocytic sarcoma in a squirrel monkey (Saimiri sciureus).

A 14-years-old squirrel monkey was euthanized due to weakness. Histopathological examination revealed multifocal growth of oval cells with severe atypia in the liver, spleen, and bone marrow. The neoplastic cells were positive for histiocytic markers (Iba1, HLA-DR, CD204). This is the fourth case of histiocytic sarcoma in non-human primates.

Optimal threshold of a control parameter for tomotherapy respiratory tracking: A phantom study.

BACKGROUND: Radixact Synchrony® , a real-time motion tracking and compensating modality, is used for helical tomotherapy. Control parameters are used for the accurate application of irradiation. Radixact Synchrony® uses the potential difference, which is an index of the accuracy of the prediction model of target motion and is represented by a statistical prediction of the 3D distance error. Although there are several reports on Radixact Synchrony® , few have reported the appropriate settings of the potential difference threshold. PURPOSE: This study aims to determine the optimal threshold of the potential difference of Radixact Synchrony® during respiratory tumor-motion-tracking irradiation. METHODS: The relationship among the dosimetric accuracy, motion tracking accuracy, and control parameter was evaluated using a moving platform, a phantom with a basic respiratory model (the fourth power of a sinusoidal wave), and several irregular respiratory model waveforms. The dosimetric accuracy was evaluated by gamma analysis (3%, 1 mm, 10% dose threshold). The tracking accuracy was measured by the distance error of the difference between the tracked and driven positions of the phantom. The largest potential difference for 95% of treatment time was evaluated, and its correlation with the gamma-pass ratio and distance error was investigated. The optimal threshold of the potential difference was determined by receiver operating characteristic (ROC) analysis. RESULTS: A linear correlation was identified between the potential difference and the gamma-pass ratio (R = -0.704). A linear correlation was also identified between the potential difference and distance error (R = 0.827). However, as the potential difference increased, it tended to underestimate the distance error. The ROC analysis revealed that the appropriate cutoff value of the potential difference was 3.05 mm. CONCLUSION: The irradiation accuracy with motion tracking by Radixact Synchrony® could be predicted from the potential difference, and the threshold of the potential difference should be set to ∼3 mm.

Dose difference between anisotropic analytical algorithm (AAA) and Acuros XB (AXB) caused by target's air content for volumetric modulated arc therapy of head and neck cancer.

Background: We clarified the dose difference between the anisotropic analytical algorithm (AAA) and Acuros XB (AXB) with increasing target's air content using a virtual phantom and clinical cases. Materials and methods: Whole neck volumetric modulated arc therapy (VMAT) plan was transferred into a virtual phantom with a cylindrical air structure at the center. The diameter of the air structure was changed from 0 to 6 cm, and the target's air content defined as the air/planning target volume (PTV) in percent (air/PTV) was varied. VMAT plans were recalculated by AAA and AXB with the same monitor unit (MU) and multi-leaf collimator (MLC) motions. The dose at each air/PTV (5%-30%) was compared between each algorithm with D98%, D95%, D50% and D2% for the PTV. In addition, MUs were also compared with the same MLC motions between the D95% prescription with AAA (AAA_D95%), AXB_D95%, and the prescription to 100% minus air/PTV (AXB_D100%-air/PTV) in clinical cases of head and neck (HNC). Results: When air/PTV increased (5-30%), the dose differences between AAA and AXB for D98%, D95%, D50% and D2% were 3.08-15.72%, 2.35-13.92%, 0.63-4.59%, and 0.14-6.44%, respectively. At clinical cases with air/PTV of 5.61% and 28.19%, compared to AAA_D95%, the MUs differences were, respectively, 2.03% and 6.74% for AXB_D95% and 1.80% and 0.50% for AXB_D100%-air/PTV. Conclusion: The dose difference between AAA and AXB increased as the target's air content increased, and AXB_D95% resulted in a dose escalation over AAA_D95% when the target's air content was ≥ 5%. The D100%-air/PTV of PTV using AXB was comparable to the D95% of PTV using AAA.

Highly feasible procedure for laparoscopic transplantation of cell sheets under pneumoperitoneum in porcine model.

INTRODUCTION: Cell sheet technology is one of the most successful methodologies in regenerative medicine. Various applications of cell sheets have been introduced in first-in-human studies in several clinical fields. When transplanting a cell sheet into internal organs, a relatively large incision is required for delivery due to difficulty handling the sheet. We developed a laparoscopic delivery procedure for safe and easy transplantation of cell sheets in a porcine model. METHODS: Pneumoperitoneum was established by inflation with CO2. First, to increase the strength during handling, fibrin was sprayed onto the surface of the cell sheet, and then a myoblast sheet was placed onto the newly developed carrier. The sheets were pinched with laparoscopic forceps to insert into the abdominal cavity through the laparoscopic port. Myoblast sheets were then applied to the surface of the liver, colon, small intestine, and stomach, and procedure times were measured. At three days post transplantation, a histopathological examination was performed to confirm engraftment of the sheet. The function and engraftment were also analyzed in a duodenal endoscopic submucosal dissection (ESD) model. RESULTS: The fibrin-processed myoblast sheet was able to be managed with conventional laparoscopic forceps without breaking. Despite the drastic change in air pressure by passing through the laparoscopic port, the sheets suffered no apparent damage. The transplantation procedure times did not markedly differ among transplant sites. A histopathological examination revealed thin-layered, desmin-positive cells at each transplant site. With transplantation following ESD, the engrafted myoblast sheets effectively prevented delayed perforation. CONCLUSIONS: Our procedure is simple, and the system involves a carrier made of medically fit silicon, commercially available fibrin glue and conventional laparoscopic forceps. Our procedure is a powerful tool for laparoscopical cell sheet transplantation.

Histopathological Characterization of Cases of Spontaneous Fatal Feline Severe Fever with Thrombocytopenia Syndrome, Japan.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tickborne infectious disease caused by SFTS virus (SFTSV). We report 7 cases of spontaneous fatal SFTS in felines. Necropsies revealed characteristic lesions, including necrotizing lymphadenitis in 5 cases and necrotizing splenitis and SFTSV-positive blastic lymphocytes in all cases. We detected hemorrhagic lesions in the gastrointestinal tract in 6 cases and lungs in 3 cases, suggesting a more severe clinical course of SFTS in felids than in humans. We noted necrotic or ulcerative foci in the gastrointestinal tract in 3 cases, the lung in 2 cases, and the liver in 4 cases. We clarified that blastic lymphocytes are predominant targets of SFTSV and involved in induction of necrotic foci. We also found that thymic epithelial cells were additional targets of SFTSV. These results provide insights for diagnosing feline SFTS during pathological examination and demonstrate the similarity of feline and human SFTS cases.

Cell-cell fusion induced by reovirus FAST proteins enhances replication and pathogenicity of non-enveloped dsRNA viruses.

Fusogenic reoviruses encode fusion-associated small transmembrane (FAST) protein, which induces cell-cell fusion. FAST protein is the only known fusogenic protein in non-enveloped viruses, and its role in virus replication is not yet known. We generated replication-competent, FAST protein-deficient pteropine orthoreovirus and demonstrated that FAST protein was not essential for viral replication, but enhanced viral replication in the early phase of infection. Addition of recombinant FAST protein enhanced replication of FAST-deficient virus and other non-fusogenic viruses in a fusion-dependent and FAST-species-independent manner. In a mouse model, replication and pathogenicity of FAST-deficient virus were severely impaired relative to wild-type virus, indicating that FAST protein is a major determinant of the high pathogenicity of fusogenic reovirus. FAST-deficient virus also conferred effective protection against challenge with lethal homologous virus strains in mice. Our results demonstrate a novel role of a viral fusogenic protein and the existence of a cell-cell fusion-dependent replication system in non-enveloped viruses.

Smith-Purcell radiation based on the transmission enhancement of a subwavelength hole array with inner tunnels.

The use and control of the extraordinary optical transmission through subwavelength hole arrays has enormous application potential in photonic devices. In this paper, we propose a subwavelength hole array with inner tunnels, for which the Smith-Purcell radiation (SPR) with this enhanced transmission phenomenon in THz is excited when the transmission peak locates in the SPR band. The SPR is monitored using particle-in-cell simulations in order to analyze the mechanisms responsible for improving the radiation coherence. Analysis of the electron energy loss reveals that the proposed subwavelength hole array with inner tunnels outperforms a conventional subwavelength grating array with respect to SPR generation efficiency. As SPR plays a significant role in research on particle diagnosis and terahertz radiation sources, the performance of the proposed structure suggests that it has high application potential.

Bioengineering of a CLiP-derived tubular biliary-duct-like structure for bile transport in vitro.

The integration of a bile drainage structure into engineered liver tissues is an important issue in the advancement of liver regenerative medicine. Primary biliary cells, which play a vital role in bile metabolite accumulation, are challenging to obtain in vitro because of their low density in the liver. In contrast, large amounts of purified hepatocytes can be easily acquired from rodents. The in vitro chemically induced liver progenitors (CLiPs) from primary mature hepatocytes offer a platform to produce biliary cells abundantly. Here, we generated a functional CLiP-derived tubular bile duct-like structure using the chemical conversion technology. We obtained an integrated tubule-hepatocyte tissue via the direct coculture of hepatocytes on the established tubular biliary-duct-like structure. This integrated tubule-hepatocyte tissue was able to transport the bile, as quantified by the cholyl-lysyl-fluorescein assay, which was not observed in the un-cocultured structure or in the biliary cell monolayer. Furthermore, this in vitro integrated tubule-hepatocyte tissue exhibited an upregulation of hepatic marker genes. Together, these findings demonstrated the efficiency of the CLiP-derived tubular biliary-duct-like structures regarding the accumulation and transport of bile.

Chemical conversion of aged hepatocytes into bipotent liver progenitor cells.

AIM: In the aging society, understanding the influence of hepatocyte age on hepatocyte donation may inform efforts to expand alternative cell sources to mitigate liver donor shortage. A combination of the molecules Y27632, A-83-01, and CHIR99021 has been used to reprogram rodent young hepatocytes into chemically induced liver progenitor (CLiP) cells; however, whether it could also reprogram aged hepatocytes has not yet been elucidated. METHODS: Primary hepatocytes were isolated from aged and young donor rats, respectively. Hepatic histological changes were evaluated. Differences in gene expression in hepatocytes were identified. The in vitro reprogramming plasticity of hepatocytes as evidenced by CLiP conversion and the hepatocyte and cholangiocyte maturation capacity of reprogrammed CLIPs were analyzed. The effect of hepatocyte growth factor (HGF) on cell propagation was also investigated. RESULTS: The histological findings revealed ongoing liver damage with inflammation, fibrosis, senescence, and ductular reaction in aged livers. Microarray analysis showed altered gene expression profiles in hepatocytes from aged donors, especially with regard to metabolic pathways. Aged hepatocytes could be converted into CLiPs (Aged-CLiPs) expressing progenitor cell markers, but with a relatively low proliferative rate compared with young hepatocytes. Aged-CLiPs possessed both hepatocyte and cholangiocyte maturation capacity. HGF facilitated CLiP conversion in aged hepatocytes, which was partly related to the activation of Erk1 and Akt1 signaling. CONCLUSIONS: Aged rat hepatocytes have retained reprogramming plasticity as evidenced by CLiP conversion in culture. HGF promoted proliferation and CLiP conversion in aged hepatocytes. Hepatocytes from aged donors may be used as an alternative cell source to mitigate donor shortage.

Minocycline prevents depression-like behavior in streptozotocin-induced diabetic mice.

Diabetes mellitus is a group of metabolic diseases characterized by hyperglycemia. Diabetic patients are known to have a higher prevalence and a higher risk of depression compared with the general population. The pathogenesis of diabetes-related depression is unclear, and the treatment is not well-established. Therefore, the prevention of diabetes-related depression is important for improving the quality of life of diabetic patients. Minocycline, a second-generation tetracycline antibiotic, has recently gained attention as a new agent for depression. In this study, we investigated the effect of minocycline on diabetes-related depression in a streptozotocin-induced mouse model of diabetes. Eight-week-old male C57BL/6 mice were injected with streptozotocin (200 mg/kg, i.p.). Seven days after injection, the mice received minocycline treatment through drinking water. We compared these mice with vehicle-treated control mice and diabetic mice not receiving minocycline treatment. On day 34, depression-like behavior was investigated using the forced swim test. On the following day, brain samples were collected, and formalin-fixed, paraffin-embedded specimens were prepared for immunohistochemistry. Compared with the control group, the diabetic mice not receiving minocycline treatment showed a prolonged duration of immobility in the forced swim test, the observation being interpreted as a depression-like behavior. Immunohistochemistry revealed an increase in microglia with an activated morphology in the diabetic mice without minocycline treatment. The expression of tumor necrosis factor alpha in microglia was increased. In addition, a decrease in the number of doublecortin-positive immature neurons was found in the hippocampus of diabetic mice. Minocycline treatment of diabetic animals prevented the depression-like behavior and microglial activation; however, minocycline did not reverse impaired hippocampal neurogenesis. These results indicate that minocycline has a preventive effect on diabetes-related depression. Inhibition of microglial activation would be a critical target for the antidepressant mechanism of minocycline. Impaired hippocampal neurogenesis was observed in diabetic mice; however, this may not be involved in the pathogenesis of depression.

Mismatch repair deficiency in canine neoplasms.

The DNA mismatch repair (MMR) system preserves genomic stability by identifying and repairing mismatched nucleotides in the DNA replication process. The dysfunction of the MMR system, also known as mismatch repair deficiency (dMMR), is implicated as a predictive biomarker for the efficacy of immune checkpoint blockade therapy regardless of the tumor type in humans. This study aimed to evaluate the immunolabeling of MMR proteins in canine tumors and to identify the types of tumors having dMMR. First, we performed immunohistochemistry in 8 different canine tumors (oral malignant melanoma, high-to-intermediate grade lymphoma, mast cell tumor, malignant mammary gland tumor, urothelial carcinoma, hepatocellular carcinoma, osteosarcoma, and hemangiosarcoma) with 15 samples each to analyze the immunolabeling of canine mismatch repair proteins (MSH2, MSH6, and MLH1) using anti-human monoclonal antibodies. We found that more than half of canine oral malignant melanoma (60%) and hepatocellular carcinoma (53%) samples and fewer of the other canine tumors had loss of immunolabeling in ≥1 MMR protein (ie, evidence of defective MMR proteins, based on the definition of dMMR in the humans). Antibodies against human MSH2, MSH6, and MLH1 were cross-reactive with the corresponding canine protein as confirmed using MMR gene knockout canine cell lines. Further studies are required to investigate the clinical outcomes in canine spontaneous tumors with dMMR to determine the potential for immune checkpoint blockade therapy for these tumor types.

Impact of mechanical stability on the progress of bone ongrowth on the frame surfaces of a titanium-coated PEEK cage and a 3D porous titanium alloy cage: in vivo analysis using CT color mapping.

PURPOSE: To determine the impact of mechanical stability on the progress of bone ongrowth on the frame surfaces of a titanium-coated polyether ether ketone (TCP) cage and a three-dimensional porous titanium alloy (PTA) cage following posterior lumbar interbody fusion (PLIF) until 1 year postoperatively. METHODS: A total of 59 patients who underwent one- or two-level PLIF for degenerative lumbar disorders since March 2015 were enrolled. Bone ongrowth of all cage frame surfaces (four surfaces per cage: TCP, 288 surfaces and PTA, 284 surfaces) was graded by 6-month and 1-year postoperative computed tomography color mapping (grade 0, 0‒25% of bone ongrowth; grade 1, 26‒50%; grade 2, 51‒75%; and grade 3, 76‒100%). RESULTS: Bone ongrowth (≥ grade 1) was observed on 58.0% and 69.0% of the surfaces of TCP and PTA cages 6 months postoperatively and on 63.5% and 75.0% of those 1 year postoperatively, respectively. In the TCP cages, bone ongrowth grade increased from 6 months to 1 year postoperatively only in the union segments (median, 1 [interquartile range, IQR, 0-2] to 1 [IQR, 0-3], p = 0.006). By contrast, in the PTA cages, it increased at 6 months postoperatively in the union (1 [IQR, 1-2] to 2 [IQR, 1-3], p = 0.003) and non-union (0.5 [IQR, 0-2] to 1 [IQR, 0-2.75], p = 0.002) segments. CONCLUSION: Early postoperative mechanical stability has a positive impact on the progress of bone ongrowth on both the TCP and PTA cage frame surfaces after PLIF.

Genetic and plastic variation in opsin gene expression, light sensitivity, and female response to visual signals in the guppy.

According to the sensory drive model, variation in visual properties can lead to diverse female preferences, which in turn results in a range of male nuptial colors by way of sexual selection. However, the cause of variation in visual properties and the mechanism by which variation drives female response to visual signals remain unclear. Here, we demonstrate that both differences in the long-wavelength-sensitive 1 (LWS-1) opsin genotype and the light environment during rearing lead to variation in opsin gene expression. Opsin expression variation affects the visual sensitivity threshold to long wavelengths of light. Moreover, a behavioral assay using digitally modified video images showed that the expression of multiple opsin genes is positively correlated with the female responsiveness to images of males with luminous orange spots. The findings suggest that genetic polymorphisms and light environment in habitats induce variations in opsin gene expression levels. The variations may facilitate variations in visual sensitivity and female responsiveness to male body colors within and among populations.