Sapovirus infections in Japan before and after the emergence of the COVID-19 pandemic: An alarming update.

An increasing trend of sapovirus (SaV) infections in Japanese children during 2009-2019, particularly after the introduction of the voluntary rotavirus (RV)-vaccination program has been observed. Herein, we investigated the epidemiological situation of SaV infections from 2019 to 2022 when people adopted a precautionary lifestyle due to the emergence of the COVID-19 pandemic, and RV vaccines had been implemented as routine vaccines. Stool samples were collected from children who attended outpatient clinics with acute gastroenteritis and analyzed by reverse transcriptase-polymerase chain reaction to determine viral etiology. Among 961 stool samples, 80 (8.3%) were positive for SaV: 2019-2020 (6.5%), 2020-2021 (0%), and 2021-2022 (12.8%). The trend of SaV infection in Japanese children yet remained upward with statistical significance (p = 0.000). The major genotype was GI.1 (75%) which caused a large outbreak in Kyoto between December 2021 and February 2022. Phylogenetic, gene sequence and deduced amino acid sequence analyses suggested that these GI.1 strains detected in the outbreak and other places during 2021-2022 or 2019-2020 remained genetically identical and widely spread. This study reveals that SaV infection is increasing among Japanese children which is a grave concern and demands immediate attention to be paid before SaV attains a serious public health problem.

Examination and reliability of measuring muscle strength of ankle plantar flexion with knee extended.

[Purpose] A hand-held dynamometer (HHD) is less expensive than the isokinetic muscle strength measurement device, and research using HHD is gradually increasing. However, measurement is performed only at a low muscle strength level at which the heel does not take off or heel detachment occurs; therefore, fixation of the foot becomes a problem. This study aimed to determine the validation of measuring ankle plantar flexion strength (with the knee extended) using HHD. [Participants and Methods] Twenty healthy adults (14 males and 6 females) participated in this study. The chair used in this study was for swallowing videofluorography, which was fixed to a wall bar by the belt. The sensor was located at the third metatarsal head. After warming up, the participants sat in a long sitting position on the chair. We conducted the test two times. We used intraclass correlation coefficient (ICC) and Bland-Altman analysis to assess reliability. [Results] The ICC(1, 1) and ICC(2, 1) results were all greater than 0.9. No fixed and proportional errors were present. [Conclusion] The measurement method of this study was both intra- and inter-examiner reliabilities, which were high, and we suggest that sufficient clinical application is possible.

Prolonged central motor conduction time and pyramidal tract degeneration in amyotrophic lateral sclerosis.

Electrophysiological methods to detect the degeneration of the upper motor neuron system have not been fully established in patients with amyotrophic lateral sclerosis (ALS). This may be partly because the parallel demonstration of electrophysiology and a corresponding pathological abnormality is insufficient, and because a substantial number of patients with ALS do not exhibit upper motor neuron degeneration. Recently, we encountered 2 patients with ALS who had been examined for abnormal central motor conduction time (CMCT) using transcranial magnetic stimulation within a 20-day period prior to their death. Autopsy revealed that 1 patient had marked pyramidal degeneration with prolonged CMCT; in contrast, the other patient had no obvious pyramidal degeneration and showed normal CMCT. Both the patients with contrasting clinicopathological differences contributed to the identification that the prolongation of CMCT was possibly linked to the degeneration of the corticospinal tract. This report indicates that CMCT is useful for predicting the severity of upper motor neuron degeneration in patients with ALS.

IgG4-related brain pseudotumor mimicking CNS lymphoma. A case report.

Here, we report a case of IgG4-related brain pseudotumor (IgG4-BP) in a 39-year-old woman, mimicking central nervous system (CNS) lymphoma. She presented with headache, fever, and fatigue. Her medical history was notable for appearance of a tumefactive brain lesion seven years before. Brain biopsy performed at the age of 32 revealed nonspecific inflammatory changes, and her condition improved with oral low-dose steroid therapy. Magnetic resonance imaging performed at the age of 39 identified a hyperintensity lesion with edema located at the medial temporal lobe region adjacent to the inferior horn of the left lateral ventricle on fluid-attenuated inversion recovery images, which showed gadolinium-contrast enhancement on T1-weighted images and a slightly hyperintensity signal on diffusion-weighted images. Methionine-positron emission tomography (PET) depicted a high methionine uptake in the lesion. Additionally, soluble levels of interleukin (IL)-2 receptor (sIL-2R) and IL-10 were increased in cerebrospinal fluid (CSF). Based on these findings, we suspected CNS lymphoma and performed partial resection of the brain lesion. Pathological examination revealed prominent lymphocytic infiltration associated with plasma cell infiltration. Most of the plasma cells were immunoreactive for IgG4. Storiform fibrosis and partially obliterative phlebitis were concomitantly observed. Thus, the patient was diagnosed as having IgG4-BP. To the best of our knowledge, this is the first case report of IgG4-BP with detailed findings obtained by CSF testing, methionine-PET, and pathological examination. Because IgG4-related diseases can present as a pseudotumor that mimics CNS lymphoma, it is essential to carefully differentiate IgG4-BP from CNS lymphoma.

The Detection of Rotavirus Antigenemia by Immunochromatographic Kits: a Case Series.

BACKGROUND: Acute gastroenteritis is the most common cause of illness and death in infants and young children worldwide. Rotaviruses (RVs) are the major viruses that cause acute gastroenteritis in young children, especially in developing countries in Asia and Africa. METHODS: The presence of rotavirus antigens in sera of four unvaccinated pediatric patients, aged between 4 and 6 years with severe diarrhea and dehydration, were detected by using three immunochromatographic (IC) kits. In addition, the presence of anti-rotavirus IgG, IgA, and IgM antibodies and their concentrations in patient sera were also determined by enzyme immunoassay (EIA). RESULTS: All three kits could detect rotavirus antigen in patient sera with different intensity of the test lines. When patient sera were pretreated with anti-VP6 rotavirus mouse monoclonal antibody prior to testing, the rotavirus positive test lines disappeared, suggesting that all patient sera contained VP6 protein antigen of rotavirus. Assessment of antibody concentration in these patient sera revealed that all patient sera contained IgG, IgA, and IgM antibodies against rotavirus antigen at different concentrations. CONCLUSIONS: The sensitivity of rotavirus protein detection in the patient sera of one IC kit brand was comparable to those of the EIA, suggesting this IC kit could be an alternative screening method for rapid diagnosis of rotavirus infection.

Association of IgG4-Related Arteritis With Recurrent Stroke.

Immunoglobulin G4-related disease (IgG4)-related disease is a newly recognized form of immune-mediated disease, which is characterized by IgG4+ lymphoplasmacytic infiltration and fibrosis in the systemic organs. Although aortitis/periaortitis is a phenotype of IgG4-related disease, the relationship between cerebrovascular disease and IgG4-related disease remains unclear. Herein, we report the case of a 49-year-old man with recurrent stroke induced by IgG4-related arteritis. Case reports or studies examining the association between IgG4-related arteritis and stroke are limited. Although a definitive link between IgG4-related arteritis and stroke has not been established, IgG4-related arteritis should be considered as an etiology in patients with recurrent idiopathic stroke.

Lotus japonicus Triterpenoid Profile and Characterization of the CYP716A51 and LjCYP93E1 Genes Involved in Their Biosynthesis In Planta.

Lotus japonicus is an important model legume plant in several fields of research, such as secondary (specialized) metabolism and symbiotic nodulation. This plant accumulates triterpenoids; however, less information regarding its composition, content and biosynthesis is available compared with Medicago truncatula and Glycine max. In this study, we analyzed the triterpenoid content and composition of L. japonicus. Lotus japonicus accumulated C-28-oxidized triterpenoids (ursolic, betulinic and oleanolic acids) and soyasapogenols (soyasapogenol B, A and E) in a tissue-dependent manner. We identified an oxidosqualene cyclase (OSC) and two cytochrome P450 enzymes (P450s) involved in triterpenoid biosynthesis using a yeast heterologous expression system. OSC9 was the first enzyme derived from L. japonicus that showed α-amyrin (a precursor of ursolic acid)-producing activity. CYP716A51 showed triterpenoid C-28 oxidation activity. LjCYP93E1 converted ß-amyrin into 24-hydroxy-ß-amyrin, a metabolic intermediate of soyasapogenols. The involvement of the identified genes in triterpenoid biosynthesis in L. japonicus plants was evaluated by quantitative real-time PCR analysis. Furthermore, gene loss-of-function analysis of CYP716A51 and LjCYP93E1 was conducted. The cyp716a51-mutant L. japonicus hairy roots generated by the genome-editing technique produced no C-28 oxidized triterpenoids. Likewise, the complete abolition of soyasapogenols and soyasaponin I was observed in mutant plants harboring Lotus retrotransposon 1 (LORE1) in LjCYP93E1. These results indicate that the activities of these P450 enzymes are essential for triterpenoid biosynthesis in L. japonicus. This study increases our understanding of triterpenoid biosynthesis in leguminous plants and provides information that will facilitate further studies of the physiological functions of triterpenoids using L. japonicus.

The Prevalence of Mixed Hepatitis C Virus Genotype Infection and Its Effect on the Response to Direct-Acting Antivirals Therapy.

BACKGROUND: The incidence of mixed hepatitis C virus (HCV) genotype infection is variable, and a few reports exist regarding the efficacy of direct-acting antivirals (DAA) therapy for mixed genotype. We aimed to investigate the prevalence of mixed genotype and its impact on the virologic response to DAA therapy. METHODS: A total of 365 patients with chronic HCV infection who completed antiviral therapy were recruited. Nested polymerase chain reaction with universal and specific primers of genotypes 1b and 2 and direct sequencing were used for HCV genotyping. RESULTS: Direct sequencing with universal primers defined genotypes 1b (n = 230), 2a (n = 95), and 2b (n = 40). Direct sequencing of genotype 2 was performed in patients with genotype 1b, and direct sequencing of genotype 1b in patients with genotype 2. Four patients with genotype 1b underwent amplification for genotype 2, and direct sequencing identified genotypes 1b (n = 1), 2a (n = 1), and 2b (n = 2). None with genotype 2 underwent amplification for genotype 1b. Three cases were confirmed to have mixed genotype. CONCLUSIONS: Mixed genotype was rare, and hence the impact of mixed genotype on treatment outcome with DAA therapy is expected to be minimal.

p.N345K mutation in TARDBP in a patient with familial amyotrophic lateral sclerosis: An autopsy case.

We report the neuropathology of a patient with a family history of amyotrophic lateral sclerosis (ALS) and a p.N345K mutation in the transactivation response DNA-binding protein 43 kDa (TDP-43) gene (TARDBP). A 62-year-old man had bulbar palsy with progressive weakness in the extremities. Neurological examination revealed evident upper motor neuron signs and lower motor neuron involvement corroborated by needle electromyography. The patient was diagnosed as having probable ALS according to the revised El Escorial diagnostic criteria and was eventually diagnosed with familial ALS. At 65 years of age, respiratory failure became critical, and artificial ventilation was initiated. At 70 years of age, the patient died from a urinary tract infection. Histopathological investigation showed Bunina bodies in the remaining motor neurons and anterolateral funicular myelin pallor in the spinal cord. TDP-43-positive cytoplasmic inclusions were quite rare in the spinal cord motor neurons, being predominantly present in the glial cells (especially astrocytes) of the spinal cord anterior horn. Although the reason for the preferential vulnerability of spinal glial cells to TARDBP mutations remains unclear, our findings indicate that TARDBP p.N345K mutation could have an influence on the topography of TDP-43 aggregation.

Estimation of reduced walking speed using simple measurements of physical and psychophysiological function in community-dwelling elderly people: a cross-sectional and longitudinal study.

BACKGROUND: Early detection of reduced mobility function is important in elderly people. Usual walking speed is useful to assess mobility function, but is often not feasible in a community setting. AIMS: This study aimed to explore a simple surrogate indicator of usual walking speed in elderly people. METHODS: The participants were 516 community-dwelling elderly people. As a baseline survey, the usual walking speed and candidates of surrogate indicators including physical function and psychophysiological function were measured. After 2 years, the occurrence of mobility limitation was assessed. RESULTS: In cross-sectional analysis, a linear regression model with maximum step length, age, and sex presented the most favourable adjusted R2 of 0.426 for estimating usual walking speed. Maximum step length (MSL) also showed good predictive accuracy for usual walking speed < 0.8 m/s {area under the curve [AUC] 0.908 [95% confidence interval (CI) 0.811, 1.000]} and < 1.0 m/s [AUC 0.883 (95% CI) 0.832, 0.933)] in receiver-operating characteristic (ROC) analysis. In longitudinal analysis, the predictive accuracy of MSL for mobility limitation [AUC 0.813 (95% CI 0.752, 0.874)] was similar to that of usual walking speed [AUC 0.808 (95% CI 0.747, 0.869)] in ROC analysis. CONCLUSIONS AND DISCUSSION: The results of this study suggest that MSL may serve as a simple surrogate indicator of UWS in elderly people.

Ischemic Stroke due to Virologically-Confirmed Varicella Zoster Virus Vasculopathy: A Case Series.

BACKGROUND: Limited data are available regarding the characteristics and prognosis of patients with stroke due to varicella zoster virus (VZV) vasculopathy. METHODS: We studied 4 patients (2 men and 2 women; age, 38-63 years) from a single center who developed acute ischemic stroke due to VZV vasculopathy. The virological diagnosis was confirmed by detecting VZV DNA and/or the IgG antibody to VZV in the cerebrospinal fluid. RESULTS: Three patients were taking immunosuppressive agents, including prednisolone and/or methotrexate, at baseline. Each patient had a characteristic skin rash prior to stroke, with the interval from rash to stroke onset ranging from 13 to 122 days. Two patients experienced antecedent cranial nerve palsies; one had the third, seventh, ninth, and 10th nerve palsies and the other had the fourth nerve palsy before stroke. Cerebral infarctions were located in the anterior circulation lesion (n = 1), in the posterior circulation lesion (n = 2), and in both lesions (n = 1). Intracranial arterial stenosis was only identified in one patient on magnetic resonance angiography. A high plasma d-dimer level was detected in 1 patient, whereas high ß-thromboglobulin and platelet factor 4 levels were detected in 2 patients. As a result of combined therapies with acyclovir, steroid, and antithrombotic agents, neurological symptoms markedly improved in 3 patients, whereas 1 patient was left with moderate hemiplegia. CONCLUSIONS: Cranial nerve palsies may be prodromal symptoms of VZV-associated stroke. Increased levels of thrombotic markers may support the use of antithrombotic agents, although the benefit of combined treatment should be determined through larger studies.

CSF and clinical data are useful in differentiating CNS inflammatory demyelinating disease from CNS lymphoma.

BACKGROUND: It is often difficult to diagnose central nervous system (CNS) inflammatory demyelinating diseases (IDDs) because they are similar to CNS lymphoma and glioma. OBJECTIVE: To evaluate whether cerebrospinal fluid (CSF) analysis can differentiate CNS IDDs from CNS lymphoma and glioma. METHODS: We measured CSF cell counts; concentrations of proteins, glucose, interleukin (IL)-6, IL-10, soluble IL-2 receptor (sIL-2R), and myelin basic protein; and IgG index in patients with multiple sclerosis (MS, n = 64), neuromyelitis optica spectrum disorder (NMOSD, n = 35), tumefactive demyelinating lesion (TDL, n = 17), CNS lymphoma ( n = 12), or glioma ( n = 10). We detected diagnostic markers using logistic regression and receiver operating characteristic (ROC) analyses. RESULTS: Median CSF IL-10 and sIL-2R levels were higher in CNS lymphoma patients than in MS, NMOSD, or TDL patients. Logistic regression revealed that CSF sIL-2R levels predicted CNS lymphoma. In the ROC analysis of CSF sIL-2R levels, the area under the curve was 0.867, and the sensitivity and specificity were 83.3% and 90.0%, respectively. CONCLUSION: CSF sIL-2R levels can be used to differentiate CNS lymphoma from CNS IDDs. Further studies may identify other applications of CSF as a diagnostic biomarker.

Pregnancy-related relapse risk factors in women with anti-AQP4 antibody positivity and neuromyelitis optica spectrum disorder.

BACKGROUND: Few reports describe the influence pregnancy has on the annualized relapse rate (ARR) in neuromyelitis optica spectrum disorder (NMOSD). OBJECTIVE: To examine pregnancy-related attacks (attacks during pregnancy or within 1 year postpartum) and identify the risk factors for an attack in Japanese NMOSD patients. METHODS: We retrospectively reviewed 139 Japanese women whom had aquaporin-4 (AQP4) antibody-positive NMOSD. Among the 114 patients with information, 47 women had 56 pregnancies. We compared the ARR before, during and after pregnancy. RESULTS: Of the 47 NMOSD patients with pregnancy, 22 women (46.8%) had a pregnancy-related attack of the disease (either an onset event or a relapse). The ARR was significantly higher in the first 3 months postpartum (1.80 ± 2.04), than before the pregnancy (0.57 ± 1.16; p = 0.0043) and did not significantly decrease during pregnancy. The ARR before hospitalization and treatment was analyzable in 55 patients without pregnancy and was 1.09 ± 1.17. Among the 11 patients with onset before pregnancy, nine patients had a pregnancy-related attack with a relapse in the previous year, and their immunosuppression was discontinued or made to be at low doses; while the two patients on higher-dose therapies were relapse-free. CONCLUSION: In the present study, pregnancy-related attack was common in NMOSD, and unlike in multiple sclerosis, the ARR was not reduced during pregnancy. Discontinued or insufficient immunosuppression appeared to increase the risk of pregnancy-related attack.

The RNA-editing enzyme APOBEC1 requires heterogeneous nuclear ribonucleoprotein Q isoform 6 for efficient interaction with interleukin-8 mRNA.

Apolipoprotein B mRNA-editing enzyme, catalytic polypeptide 1 (APOBEC1) is an intestine-specific RNA-binding protein. However, inflammation or exposure to DNA-damaging agents can induce ectopic APOBEC1 expression, which can result in hepatocellular hyperplasia in animal models. To identify its RNA targets, FLAG-tagged APOBEC1 was immunoprecipitated from transfected HuH7.5 hepatocellular carcinoma cells and analyzed using DNA microarrays. The interleukin-8 (IL8) mRNA was the most abundant co-precipitated RNA. Exogenous APOBEC1 expression increased IL8 production by extending the half-life of the IL8 mRNA. A cluster of AU-rich elements in the 3'-UTR of IL8 was essential to the APOBEC1-mediated increase in IL8 production. Notably, IL8 mRNA did not co-immunoprecipitate with APOBEC1 from lysates of other cell types at appreciable levels; therefore, other factors may enhance the association between APOBEC1 and IL8 mRNA in a cell type-specific manner. A yeast two-hybrid analysis and siRNA screen were used to identify proteins that enhance the interaction between APOBEC1 and IL8 mRNA. Heterogeneous nuclear ribonucleoprotein Q (hnRNPQ) was essential to the APOBEC1/IL8 mRNA association in HuH7.5 cells. Of the seven hnRNPQ isoforms, only hnRNPQ6 enabled APOBEC1 to bind to IL8 mRNA when overexpressed in HEK293 cells, which expressed the lowest level of endogenous hnRNPQ6 among the cell types examined. The results of a reporter assay using a luciferase gene fused to the IL8 3'-UTR were consistent with the hypothesis that hnRNPQ6 is required for APOBEC1-enhanced IL8 production. Collectively, these data indicate that hnRNPQ6 promotes the interaction of APOBEC1 with IL8 mRNA and the subsequent increase in IL8 production.

Novel reporter system to monitor early stages of the hepatitis B virus life cycle.

A recombinant hepatitis B virus (HBV) expressing NanoLuc (NL) (HBV/NL) was produced by cotransfecting a plasmid containing a 1.2-fold HBV genome carrying the NL gene with a plasmid bearing a packaging-defective 1.2-fold HBV genome into a human hepatoma cell line, HepG2. We found that NL activity in HBV/NL-infected primary hepatocytes or sodium taurocholate cotransporting polypeptide-transduced human hepatocyte-derived cell lines increased linearly for several days after infection and was concordant with HBV RNA levels in the cells. Treatment of the virus-infected cells with HBV inhibitors reduced NL activity in a dose-dependent manner. Detection of HBV/NL infection, monitored by NL activity, was highly sensitive and less expensive than detection using the conventional method to evaluate HBV infection. In addition, because we also studied host factors, this system is applicable not only for studying the HBV life cycle, but also for exploring agent(s) that regulate HBV proliferation.

Quality control of plasma membrane proteins by Saccharomyces cerevisiae Nedd4-like ubiquitin ligase Rsp5p under environmental stress conditions.

In Saccharomyces cerevisiae, when a rich nitrogen source such as ammonium is added to the culture medium, the general amino acid permease Gap1p is ubiquitinated by the yeast Nedd4-like ubiquitin ligase Rsp5p, followed by its endocytosis to the vacuole. The arrestin-like Bul1/2p adaptors for Rsp5p specifically mediate this process. In this study, to investigate the downregulation of Gap1p in response to environmental stresses, we determined the intracellular trafficking of Gap1p under various stress conditions. An increase in the extracellular ethanol concentration induced ubiquitination and trafficking of Gap1p from the plasma membrane to the vacuole in wild-type cells, whereas Gap1p remained stable on the plasma membrane under the same conditions in rsp5(A401E) and Δend3 cells. A (14)C-labeled citrulline uptake assay using a nonubiquitinated form of Gap1p (Gap1p(K9R/K16R)) revealed that ethanol stress caused a dramatic decrease of Gap1p activity. These results suggest that Gap1p is inactivated and ubiquitinated by Rsp5p for endocytosis when S. cerevisiae cells are exposed to a high concentration of ethanol. It is noteworthy that this endocytosis occurs in a Bul1/2p-independent manner, whereas ammonium-triggered downregulation of Gap1p was almost completely inhibited in Δbul1/2 cells. We also found that other environmental stresses, such as high temperature, H2O2, and LiCl, also promoted endocytosis of Gap1p. Similar intracellular trafficking caused by ethanol occurred in other plasma membrane proteins (Agp1p, Tat2p, and Gnp1p). Our findings suggest that stress-induced quality control is a common process requiring Rsp5p for plasma membrane proteins in yeast.

[A CASE OF G-CSF PRODUCING SARCOMATOID CARCIONOMA OF URETER].

We report a case of sarcomatoid carcinoma of the ureter in a 82-year-old woman. She was admitted to our hospital with right hydronephrosis. A computed tomography (CT) and retrograde pyelography (RP) showed a solid tumor at right ureter with right hydronephrosis and 3 cm solid tumor on the right abdominal wall. She underwent laparoscopic nephroureterectomy and excision of abdominal subcutaneous tumor. Pathological diagnosis was urothelial carcinoma with sarcomatoid variant, pT3, grade 3 and abdominal wall metastasis. Other metastasis occured in left kidney and ileum about 1 month after the operation, and then she underwent laparoscopic partial nephrectomy and ileocecal resection. The histopathological diagnosis was sarcomatoid carcinoma with positive staining for granulocyte-colony stimulating factor (G-CSF). The paient died of multiple metastases 5 months after first operation. As far as we know, this is the first report of G-CSF producing infiltrating sarcomatoid carcinoma of the ureter in Japanese paper.

[Transesophageal Echocardiography Was Useful to Determine a Therapeutic Strategy for Coronary Artery Ischemia during Surgery for Acute Type A Aortic Dissection: A Case Report].

A 57-year-old woman presented with acute back pain, diagnosed with acute type A aortic dissection, and we performed emergency ascending aortic replacement. During surgery, until cardiopulmonary bypass was started, the dissection did not extend to the orifice of the both coronary arteries. When aortic replacement was completed and just after the return of spontaneous beating, ventricular fibrillation (Vf) suddenly occurred. At that time, transesophageal echocardiography (TEE) revealed that dissection extended from the left main trunk (LMT) to the left circumflex artery (LCX). Recurrent Vf and circulatory collapse necessitated the application of a percutaneous cardiopulmonary support system (PCPS), while the surgeons performed cardiac massage. Additional emergency coronary artery bypass surgery (CABG) was immediately implemented. After the CABG, TEE showed that the true lumens of the LMT and LCX were dilated, allowing an increased flow to the LAD and LCX. The patient was discharged 2 months later. Although rare, coronary ischemia can be a complication of acute aortic dissection, resulting in decreased survival. Development of dissection to the coronary artery can also occur both intra- and postoperatively. In such instances, rapid diagnosis and treatment are important to save the patient.

Reduced adult hippocampal neurogenesis and working memory deficits in the Dgcr8-deficient mouse model of 22q11.2 deletion-associated schizophrenia can be rescued by IGF2.

DiGeorge syndrome chromosomal region 8 (Dgcr8), a candidate gene for 22q11.2 deletion-associated schizophrenia, encodes an essential component for microRNA (miRNA) biosynthesis that plays a pivotal role in hippocampal learning and memory. Adult neurogenesis is known to be important in hippocampus-dependent memory, but the role and molecular mechanisms of adult neurogenesis in schizophrenia remain unclear. Here, we show that Dgcr8 heterozygosity in mice leads to reduced cell proliferation and neurogenesis in adult hippocampus, as well as impaired hippocampus-dependent learning. Several schizophrenia-associated genes were downregulated in the hippocampus of Dgcr8(+/-) mice, and one of them, insulin-like growth factor 2 (Igf2), rescued the proliferation of adult neural stem cells both in vitro and in vivo. Furthermore, IGF2 improved the spatial working memory deficits in Dgcr8(+/-) mice. These data suggest that defective adult neurogenesis contributes to the cognitive impairment observed in 22q11.2 deletion-associated schizophrenia and could be rectified by IGF2.

Enhanced electrical responsiveness in the cerebral cortex with oral melatonin administration after a small hemorrhage near the internal capsule in rats.

Intracerebral hemorrhage (ICH) can cause direct brain injury at the insult site and indirect damage in remote brain areas. Although a protective effect of melatonin (ML) has been reported for ICH, its detailed mechanisms and effects on remote brain injury remain unclear. To clarify the mechanism of indirect neuroprotection after ICH, we first investigated whether ML improved motor function after ICH and then examined the underlying mechanisms. The ICH model rat was made by collagenase injection into the left globus pallidus, adjacent to the internal capsule. ML oral administration (15 mg/kg) for 7 days after ICH resulted in significant recovery of motor function. Retrograde labeling of the corticospinal tract by Fluoro-Gold revealed a significant increase in numbers of positive neurons in the cerebral cortex. Immunohistological analysis showed that ML treatment induced no difference in OX41-positive activated microglia/macrophage at day 1 (D1) but a significant reduction in 8-hydroxydeoxyguanosin-positive cells at D7. Neutral red assay revealed that ML significantly prevented H2 O2 -induced cell death in cultured oligodendrocytes and astrocytes but not in neurons. Electrophysiological response in the cerebral cortex area where the number of Fluoro-Gold-positive cells was increased was significantly improved in ML-treated rats. These data suggest that ML improves motor abilities after ICH by protecting oligodendrocytes and astrocytes in the vicinity of the lesion in the corticospinal tract from oxidative stress and causes enhanced electrical responsiveness in the cerebral cortex remote to the ICH pathology.