Motor training promotes both synaptic and intrinsic plasticity of layer V pyramidal neurons in the primary motor cortex

Layer V neurons in the primary motor cortex (M1) are important for motor skill learning. Since pretreatment of either CNQX or APV in rat M1 layer V impaired rotor rod learning, we analysed training-induced synaptic plasticity by whole-cell patch-clamp technique in acute brain slices. Rats trained for 1 day showed a decrease in small inhibitory postsynaptic current (mIPSC) frequency and an increase in the paired-pulse ratio of evoked IPSCs, suggesting a transient decrease in presynaptic GABA release in the early phase. Rats trained for 2 days showed an increase in miniature excitatory postsynaptic current (mEPSC) amplitudes/frequency and elevated AMPA/NMDA ratios, suggesting a long-term strengthening of AMPA receptor-mediated excitatory synapses. Importantly, rotor rod performance in trained rats was correlated with the mean mEPSC amplitude and the frequency obtained from that animal. In current-clamp analysis, 1-day-trained rats transiently decreased the current-induced firing rate, while 2-day-trained rats returned to pre-training levels, suggesting dynamic changes in intrinsic properties. Furthermore, western blot analysis of layer V detected decreased phosphorylation of Ser^408-409 in GABA_A receptor β₃ subunits in 1-day-trained rats, and increased phosphorylation of Ser⁸³¹ in AMPA receptor GluA1 subunits in 2-day-trained rats. Finally, live-imaging analysis of Thy1-YFP transgenic mice showed that the training rapidly recruited a substantial number of spines for long-term plasticity in M1 layer V neurons. Taken together, these results indicate that motor training induces complex and diverse plasticity in M1 layer V pyramidal neurons. KEY POINTS: Here we examined motor training-induced synaptic and intrinsic plasticity of layer V pyramidal neurons in the primary motor cortex. The training reduced presynaptic GABA release in the early phase, but strengthened AMPA receptor-mediated excitatory synapses in the later phase: acquired motor performance after training correlated with the strength of excitatory synapses rather than inhibitory synapses. As to the intrinsic property, the training transiently decreased the firing rate in the early phase, but returned to pre-training levels in the later phase. Western blot analysis detected decreased phosphorylation of Ser^408-409 in GABA_A receptor β₃ subunits in the acute phase, and increased phosphorylation of Ser⁸³¹ in AMPA receptor GluA1 subunits in the later phase. Live-imaging analysis of Thy1-YFP transgenic mice showed rapid and long-term spine plasticity in M1 layer V neurons, suggesting training-induced increases in self-entropy per spine.

Clinical trajectory and outcomes of patients with heart failure with preserved ejection fraction with normal or indeterminate diastolic function

Background

Heart failure (HF) with preserved ejection fraction (HFpEF) is a chronic and progressive disease, but limited therapeutic strategies are currently available. Although left ventricular diastolic dysfunction (DD) is a prominent mechanism of HFpEF, a certain number of patients with HFpEF have a normal diastolic function (ND) or indeterminate diastolic function (ID). With the progressive nature of HFpEF, diastolic function may change over time. However, the change of diastolic function, its predictor and prognosis in patients with clinically established HFpEF remains unknown.

Purpose

To investigate the clinical trajectory and outcomes of patients with HFpEF with ND or ID and to identify factors associated with progression from ND or ID at discharge to DD at 1-year follow-up.

Methods

Using data from a prospective multicenter observational study of patients with HFpEF, we extracted 289 patients with HFpEF with ND or ID at discharge who had echocardiographic data at 1-year follow-up for the re-evaluation of diastolic function. Diastolic function was assessed according to the 2016 American Society of Echocardiography recommendations. Patients were classified according to the absence or presence of progression from ND or ID to DD at 1 year. The primary endpoint was a composite of all-cause death and HF rehospitalization.

Results

Median age was 81 years, and 138 (47.8%) patients were female. At 1 year, 107 (37%) patients progressed to DD. During a median follow-up of 709 days, the composite endpoint occurred in 90 (31.1%) patients. Compared to patients without progression to DD, those with progression to DD had a significantly higher cumulative incidence rate of the composite endpoint (incidence rate: 11.7/100 person-year versus 23.3/100 person-year, P<0.001). Progression to DD (adjusted HR: 2.014, 95% CI: 1.239–3.273, P=0.005) was independently associated with the composite endpoint. Age (adjusted OR: 1.046, 95% CI: 1.008–1.087, P=0.018), body mass index (BMI) (adjusted OR: 1.107, 95% CI: 1.029–1.192, P=0.006), and serum albumin (adjusted OR: 0.459, 95% CI: 0.216–0.974, P=0.042) were independently associated with progression from ND or ID to DD at 1 year.

Conclusion

More than one-third of patients with HFpEF with ND or ID progressed to DD at 1 year and had poor clinical outcomes. Age, BMI, and serum albumin were independently associated with this progression.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by grants from Japan Society for the Promotion of Science KAKENHI (No. JP 17K09496) and Japan Agency for Medical Research and Development (No. JP16lk1010013).

Association between prognosis and the use of angiotensin-converting enzyme inhibitors and/or angiotensin II receptor blocker in frail patients with heart failure with preserved ejection fraction

Background

The effectiveness of angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin II receptor blockers (ARB) has not been demonstrated in patients with heart failure with preserved ejection fraction (HFpEF). We recently reported significant interaction between the use of ACE-I and/or ARB (ACE-I/ARB) and frailty on prognosis in patients with HFpEF.

Purpose

In the present study, we examined the association between ACE-I/ARB and prognosis in patients with HFpEF stratified by the presence or absence of frailty.

Methods

We examined the association between the use of ACE-I/ARB and prognosis according to the presence (Clinical Frailty Scale (CFS) ≥5) or absence (CFS ≤4) of frailty in patients with HFpEF in a post-hoc analysis of registry data. Primary endpoint was the composite of all-cause mortality and heart failure admission. Secondary endpoints were all-cause mortality and heart failure admission.

Results

Of 1059 patients, median age was 83 years and 45% were male. Kaplan-Meier analysis showed that the risk of composite endpoint (log-rank P=0.001) and all-cause death (log-rank P=0.005) in patients with ACE-I/ARB was lower in those with CFS ≥5, but similar between patients with and without ACE-I/ARB in patients with CFS ≤4 (composite endpoint: log-rank P=0.830; all-cause death: log-rank P=0.192). In a multivariable Cox proportional hazards model, use of ACE-I/ARB was significantly associated with lower risk of the composite endpoint (hazard ratio = 0.52, 95% CI: 0.33–0.83, P=0.005) and heart failure admission (hazard ratio = 0.45, 95% CI: 0.25–0.83, P=0.010) in patients with CFS ≥5, but not in patients with CFS ≤4 (composite endpoint: hazard ratio = 1.41, 95% CI: 0.99–2.02, P=0.059; heart failure admission: hazard ratio = 1.43, 95% CI: 0.94–2.18, P=0.091). The association between ACE-I or ARB and prognosis did not significantly differ by CFS (CFS ≤4: log-rank P=0.562; CFS ≥5: log-rank P=0.100, for with ACE-I vs. ARB, respectively). Adjusted HRs for CFS 1–4 were higher than 1.0, but were less than 1.0 at CFS 5.

Conclusions

In patients with HFpEF, use of ACE-I/ARB was associated with better prognosis in patients with frailty as assessed with the CFS, but not in those without frailty.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Roche

Premature atrial contraction on Holter electrocardiogram predicts the recurrence of atrial fibrillation after catheter ablation

Introduction

It is important to detect the recurrence of atrial fibrillation (AF) after catheter ablation (CA) early, but the method of detection has not been established. The purpose of this study is to determine whether 24-h Holter electrocardiogram (ECG) can predict the recurrence of AF after CA.

Methods

We studied 336 patients of 497 patients enrolled in EARNEST-PVI trial to investigate whether the total number of premature atrial contraction (PAC) and the maximum number of PAC run by 24-h Holter ECG at 6 months after CA predicted AF recurrence after 6 months. We excluded 86 patients with recurrence by 6 months after CA and 75 patients without Holter ECG at 6 months after CA.

Results

Median age was 66 years, male were 77% and median follow-up period was 1138 days. Receiver operating characteristic curve analysis identified the total number of PAC ≥270 beats and the maximum number of PAC run ≥8 beats as the optimal cutoff for prediction of AF recurrence. Kaplan-Meier analysis showed patients with the total number of PAC ≥270 beats had more frequent AF recurrence than those without (Kaplan-Meier estimated 3-year AF recurrence rate 34% vs. 17%, Log-rank P=0.001) and patients with the maximum number of PAC run ≥8 beats had more frequent AF recurrence than those without (Kaplan-Meier estimated 3-year AF recurrence rate 33% vs. 20%, Log-rank P=0.006). Multivariate analysis revealed that the total number of PAC ≥270 beats and the maximum number of PAC run were significantly associated with AF recurrence (hazard ratio [95% confidence interval] 1.83 [1.16–2.91], P=0.01 and 1.01 [1.01–1.02], P=0.001, respectively)

Conclusion

The total number of PAC and the maximum number of PAC run on the Holter ECG may be useful in predicting AF recurrence after CA.

Funding Acknowledgement

Type of funding sources: None.

Usefulness of the synthesized 18-lead ECG in identify the origin of premature ventricular contractions

Background

There are have been reports on the 12-lead ECG waveforms used to identify ventricular premature contractions (VPCs), but there are not enough algorithms. On the other hand, the synthesized 18-lead ECG adds the right-side chest leads (V3R, V4R, and V5R) and back leads (V7, V8, and V9) to the 12-lead ECG.

Purpose

This aim of this study was to evaluate whether the waveforms of the 18-lead ECG are useful in predicting the origin of VPCs.

Methods

We studied 86 consecutive patients (age :61.8±16.0 years, male: 54.5%) enrolled from multicenter who underwent radiofrequency catheter ablation for VPCs. We retrospectively investigated the association between origin of the VPCs and characteristics of the synthetic 18-leads ECG.

Results

The 18-lead ECG showed a specific pattern for the VPC originating near the His-bundle. In 17 cases, the QRS morphology in V5R exhibited a QS pattern, and 13 of 17 cases had VPCs originating near the His-bundle. In the other 69 cases, V5R did not exhibit a QS pattern. ROC curve analysis showed that the QS pattern in V5R predicted VPC originating near the His-bundle with high accuracy: sensitivity 100.0%, specificity 94.5%, and AUC 0.98. Furthermore, the positive predictive value was 76.5% and negative predictive value 100.0%.

Conclusion

The QS pattern shown in V5R of the 18-lead ECG was a useful parameter for identifying VPCs originating near the His-bundle, which might be a good reference indicator during radiofrequency catheter ablation for VPCs.

Funding Acknowledgement

Type of funding sources: None.

Prognostic factors in patients with acute myocardial infarction underwent extracorporeal membrane oxygenation in hospital or out-of-hospital cardiac arrest

Background

Patients with acute myocardial infarction (AMI) who require extracorporeal membrane oxygenation (ECMO) have worse outcomes than those who do not, and patients with AMI with out-of-hospital cardiac arrest (OHCA) also have worse outcomes than those without OHCA. However, there have been still unclear points regarding the prognostic factors of AMI patients who underwent ECMO with or without OHCA. The aim of this study was to investigate the prognostic factors of AMI patients who underwent ECMO with and without OHCA, respectively.

Methods/Results

Ninety-eight consecutive patients (age:67±11 years, male:83.7%) who underwent ECMO for AMI were enrolled from November 2008 to December 2020. The primary endpoint was in-hospital mortality within 30-day, and we investigated the risk factors associated with 30-day mortality in AMI patients underwent ECMO with or without OHCA, respectively. In the group with OHCA (n=47), 30-day death occurred in 22 patients (47%). BMI, lactate and serum creatinine levels after the introduction of ECMO were significantly greater in patients with than without 30-day death (27.0±5.2 vs 21.0±2.9 kg/m2, p<0.001, 12.1±4.3 vs 7.5±3.6 mmol/L, p<0.001, 1.68±1.24 vs 1.41±1.07 mg/dL, p=0.039, respectively). The multivariate regression analysis showed that lactate level was independently associated with the poor outcome (Odds ratio: 1.32, 95% CI: 1.11–1.57, p<0.001). ROC curve analysis showed that the cut-off values: 7.8mmol/L of lactate had moderate accuracy to predict 30-day mortality (sensitivity:76%, specificity:86%, AUC:0.81). In the group without OHCA (n=51), 30-day death occurred in 20 patients (39%). The frequency of ventricular tachycardia / fibrillation (VT/VF) at initiation of ECMO was significantly higher (61.3% vs 25.0%, p=0.021), the frequency of mechanical complication was significantly lower (6.5% vs 30.0%, p=0.045) in patients without 30-day death than with 30-day death. The multivariate regression analysis showed that VT/VF at initiation of ECMO was independently associated with good outcome (Odds ratio: 0.21, 95% CI: 0.06–0.73, p=0.01).

Conclusions

With OHCA, increased lactate was the risk factor that was significantly associated with poor outcome in AMI patients underwent ECMO. Without OHCA, AMI patients who underwent ECMO due to rhythm trouble such as VT/VF had a good outcome. ECMO patients with AMI may have different prognostic factors with or without OHCA.

Funding Acknowledgement

Type of funding sources: None. Patient characteristics

Cardiac factors as well as non-cardiac factors were associated with frailty in patients with heart failure with preserved ejection fraction

Background

Frailty is associated with malnutrition and poor prognosis in patients with heart failure with preserved ejection fraction (HFpEF). However, the cardiac factors associated with frailty have not been fully examined in patients with HFpEF.

Purpose

The purpose of this study is to clarify the cardiac factors related to frailty in patients with HFpEF.

Methods

Of the 756 patients who registered prospective, multicenter, observational study of patients with HFpEF (PURSUIT-HFpEF) registry, 481 cases with clinical frailty score (CFS) and prognosis after discharge were examined. Frailty was defined as CFS ≥5. Outcomes were composite endpoint of all-cause death and heart failure readmission, and all-cause mortality. We compared outcomes between patients without and with frailty, and sought to identify factors which were associated with increase in clinical frailty score by the correlation analysis and linear regression analysis.

Results

Of 481 patients, 131 patients (27.2%) were frail. Male gender was less in patients with frailty than those without frailty (26.7% vs 73.3%, P<0.001). Frail patients had higher age (85.2±7.3 vs 78.7±9.4 years, P<0.001). During follow-up period of 396 [343, 697] days, composite endpoint (Kaplan-Meier event rate estimates, 77% vs. 60%; log-rank P<0.001), and all-cause mortality (Kaplan-Meier event rate estimates, 57% vs. 28%; log-rank P<0.001) was higher in patients with frailty than those without frailty. Multivariate Cox regression analysis revealed frailty was significantly and independently associated with mortality (HR=1.40, 95% CI=1.17–1.68, P<0.001). CFS was significantly correlated with age (r=0.401, P<0.001), sex (r=0.223, P<0.001), body mass index (r=−0.146, P=0.001), hemoglobin (r=−0.148, P=0.001), albumin (r=−0.222, P<0.001), left ventricular diastolic diameter (r=−0.184, P<0.001), interventricular septum thickness (r=−0.124, P=0.008), left ventricular mass (r=−0.217, P<0.001), tricuspid annular plane systolic excursion (r=−0.165, P=0.001), and tricuspid regurgitation pressure gradient (TRPG) (r=0.189, P<0.001). Multivariate linear regression analysis using these factors as covariates revealed age (standardized β: 0.337, P<0.001), sex (standardized β: 0.120, P=0.014), albumin (standardized β: −0.151, P=0.003) and TRPG (standardized β: 0.129, P=0.005) were significantly and independently associated with increase in clinical frailty score.

Conclusion

Our results suggest that not only nutritional factors but also a cardiac factor were associated with frailty, and frailty was associated with mortality in patients with HFpEF. Improvement of hemodynamics in HFpEF patients as well as improvement of nutrition might contribute to alleviation of frail in HFpEF patients.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Roche Diagnostics K.K.; Fuji Film Toyama Chemical Co. Ltd.

Learning Promotes Subfield-Specific Synaptic Diversity in Hippocampal CA1 Neurons

The hippocampus is functionally heterogeneous between the dorsal and ventral subfields with left–right asymmetry. To determine the possible location of contextual memory, we performed an inhibitory avoidance task to analyze synaptic plasticity using slice patch-clamp technique. The training bilaterally increased the AMPA/NMDA ratio at dorsal CA3–CA1 synapses, whereas the training did not affect the ratio at ventral CA3–CA1 synapses regardless of the hemisphere. Moreover, sequential recording of miniature excitatory postsynaptic currents and miniature inhibitory postsynaptic currents from the same CA1 neuron clearly showed learning-induced synaptic plasticity. In dorsal CA1 neurons, the training dramatically strengthened both excitatory and inhibitory postsynaptic responses in both hemispheres, whereas the training did not promote the plasticity in either hemisphere in ventral CA1 neurons. Nonstationary fluctuation analysis further revealed that the training bilaterally increased the number of AMPA or GABA_A receptor channels at dorsal CA1 synapses, but not at ventral CA1 synapses, suggesting functional heterogeneity of learning-induced receptor mobility. Finally, the performance clearly impaired by the bilateral microinjection of plasticity blockers in dorsal, but not ventral CA1 subfields, suggesting a crucial role for contextual learning. The quantification of synaptic diversity in specified CA1 subfields may help us to diagnose and evaluate cognitive disorders at the information level.

P5734The outcome of intra-aortic balloon pumping support for acute myocardial infarction with extracorporeal membrane oxygenation therapy

Background

It has been reported that intra-aortic balloon pumping (IABP) support for acute myocardial infarction (AMI) with cardiogenic shock did not reduce short and long-term mortality. However, the significance of IABP support for AMI patients with extracorporeal membrane oxygenation (ECMO) therapy remains unclear. The aim of this study was to investigate the effect of IABP support for the short and long-term outcome in AMI patients who received ECMO.

Methods

Using the database of the Osaka Acute Coronary Insufficiency Study (OACIS), 12,093 consecutive AMI patients were enrolled in this analysis. Among these, we analyzed 520 patients with ECMO. We classified the patients into two groups, patients who received IABP support [IABP group (n=460)] and patients who did not [no IABP group (n=60)]. Primary outcome was all-cause death.

Results

Study patients had following baseline clinical characteristics, age: 66.8±12.0 year old, male: 78.3%, diabetes mellitus: 41.0%, Killip class≥II: 66.2%, multi-vessel disease: 72.3%, peak creatine phosphokinase >3000IU/L: 68.1%. During a mean follow-up period of 349±625 days, Kaplan-Meier analysis revealed that the all-cause death was significantly lower in IABP group than no IABP group for 30-day (45.5% vs 72.7%, log-rank p<0.001) and long-term (66.2% vs 78.4%, Log rank p=0.005) follow-up period. Cox multivariate analysis revealed that IABP support was significantly associated with a reduced risk of mortality (Hazard ratio 0.445, 95% confidence interval 0.289 to 0.687, p<0.001).

Conclusions

IABP support for AMI patients with ECMO was significantly associated with reduced risks of the short and long-term mortality, suggesting that IABP support might contribute to improvement of the survival in AMI patients with ECMO.

A cross-sectional study to quantify the prevalence of avian influenza viruses in poultry at intervention and non-intervention live bird markets in central Vietnam, 2014

In Vietnam, live bird markets are found in most populated centres, providing the means by which fresh poultry can be purchased by consumers for immediate consumption. Live bird markets are aggregation points for large numbers of poultry, and therefore, it is common for a range of avian influenza viruses to be mixed within live bird markets as a result of different poultry types and species being brought together from different geographical locations. We conducted a cross-sectional study in seven live bird markets in four districts of Thua Thien Hue Province in August and December, 2014. The aims of this study were to (i) document the prevalence of avian influenza in live bird markets (as measured by virus isolation); and (ii) quantify individual bird-, seller- and market-level characteristics that rendered poultry more likely to be positive for avian influenza virus at the time of sale. A questionnaire soliciting details of knowledge, attitude and avian influenza practices was administered to poultry sellers in study markets. At the same time, swabs and faecal samples were collected from individual poultry and submitted for isolation of avian influenza virus. The final data set comprised samples from 1,629 birds from 83 sellers in the seven live bird markets. A total of 113 birds were positive for virus isolation; a prevalence of 6.9 (95% CI 5.8-8.3) avian influenza virus-positive birds per 100 birds submitted for sale. After adjusting for clustering at the market and individual seller levels, none of the explanatory variables solicited in the questionnaire were significantly associated with avian influenza virus isolation positivity. The proportions of variance at the individual market, seller and individual bird levels were 6%, 48% and 46%, respectively. We conclude that the emphasis of avian influenza control efforts in Vietnam should be at the individual seller level as opposed to the market level.

Roles of basophils and mast cells infiltrating the lung by multiple antigen challenges in asthmatic responses of mice

BACKGROUND AND PURPOSE

Mast cell hyperplasia has been observed in the lungs of mice with experimental asthma, but few reports have studied basophils. Here, we attempted to discriminate and quantify mast cells and basophils in the lungs in a murine asthma model, determine if both cells were increased by multiple antigen challenges and assess the roles of those cells in asthmatic responses.

EXPERIMENTAL APPROACH

Sensitized Balb/c mice were intratracheally challenged with ovalbumin four times. Mast cells and basophils in enzymatically digested lung tissue were detected by flow cytometry. An anti-FcεRI monoclonal antibody, MAR-1, was i.p. administered during the multiple challenges.

KEY RESULTS

The numbers of both mast cells (IgE(+) C-kit(+) ) and basophils (IgE(+) C-kit(-) CD49b(+) ) increased in the lungs after three challenges. Treatment with MAR-1 completely abolished the increases; however, a late-phase increase in specific airway resistance (sRaw), and airway eosinophilia and neutrophilia were not affected by the treatment, although the early-phase increase in sRaw was suppressed. MAR-1 reduced antigen-induced airway IL-4 production. Basophils infiltrating the lung clearly produced IL-4 after antigen stimulation in vitro; however, histamine and murine mast cell protease 1 were not increased in the serum after the challenge, indicating that mast cell activation was not evoked.

CONCLUSION AND IMPLICATIONS

Both mast cells and basophils infiltrated the lungs by multiple intratracheal antigen challenges in sensitized mice. Neither mast cells nor basophils were involved in late-phase airway obstruction, although early-phase obstruction was mediated by basophils. Targeting basophils in asthma therapy may be useful for an early asthmatic response.

The infection of mouse preimplantation embryos to Sendai virus (parainfluenza I)

To provide information on the susceptibility of mouse embryos to Sendai virus, it was investigated if viral replication occurs in the preimplantation embryo at different stages of development, with or without the zona pellucida (ZP). Mice were induced to superovulate, and embryos were collected on Days 2, 3 and 4 after mating. The ZP was removed by digestion with 0.5% pronase. Embryos were exposed to Sendai virus, washed, and allowed to develop in fresh culture medium. The presence of viral antigen in the embryonic cells was examined by the fluorescent antibody test (FAT). Specific immunofluorescence was demonstrated in the ZP-free morula and ZP-intact blastocyst. However, viral antigen was not detected in the ZP-intact two-cell, four-cell, eight-cell or morula stage embryos. Infected embryos developed normally to expanded blastocysts. These findings show that mouse embryonic cells are permissive hosts to Sendai virus replication and that the ZP played the role of a barrier against the virus.

Roles of aquaporin-3 water channels in volume-regulatory water flow in a human epithelial cell line

Membrane water transport is an essential event not only in the osmotic cell volume change but also in the subsequent cell volume regulation. Here we investigated the route of water transport involved in the regulatory volume decrease (RVD) that occurs after osmotic swelling in human epithelial Intestine 407 cells. The diffusion water permeability coefficient (Pd) measured by NMR under isotonic conditions was much smaller than the osmotic water permeability coefficient (Pf) measured under an osmotic gradient. Temperature dependence of Pf showed the Arrhenius activation energy (Ea) of a low value (1.6 kcal/mol). These results indicate an involvement of a facilitated diffusion mechanism in osmotic water transport. A mercurial water channel blocker (HgCl(2)) diminished the Pf value. A non-mercurial sulfhydryl reagent (MMTS) was also effective. These blockers of water channels suppressed the RVD. RT-PCR and immunocytochemistry demonstrated predominant expression of AQP3 water channel in this cell line. Downregulation of AQP3 expression induced by treatment with antisense oligodeoxynucleotides was found to suppress the RVD response. Thus, it is concluded that AQP3 water channels serve as an essential pathway for volume-regulatory water transport in, human epithelial cells.

Brain lesions in young broiler chickens naturally infected with a mesogenic strain of Newcastle disease virus

Thirty-nine 4- to 5-week-old broiler chickens from an outbreak of Newcastle disease (ND) in Japan were examined pathologically. The causative agent was identified as a mesogenic strain of ND virus. Predominant gross lesions included haemorrhage in the lungs, congestion of the trachea, splenomegaly, atrophy of the thymus and bursa of Fabricius, and whitish discolouration of the brain. Microscopically, there was mild haemorrhagic pneumonia, catarrhal tracheitis, lymphoid necrosis in the spleen, thymus, bursa of Fabricius and caecum and diffuse non-suppurative encephalitis. Lesions associated with encephalitis were characterized by multifocal perivascular cuffing, malacia, demyelination and proliferative vasculitis. Malacic lesions occurred in the hyperstriatum, neostriatum, subleptomeningeal and periventricular regions of the cerebrum, whereas demyelination was seen mainly in the brain stem. The morphological changes that occurred in the brain in these cases were distinctive and the lesions in the lymphoid tissues were related to concurrent infection with infectious bursal disease virus.

Carboxyl terminus of the 34 kDa protein of Mycobacterium paratuberculosis shares homologous B-cell epitopes with Mycobacterium avium and Mycobacterium intracellulare

Monoclonal antibodies (mAbs) against a recombinant carboxyl terminus of the 34 kDa protein of Mycobacterium paratuberculosis were produced in mice. Two of the mAbs cross-reacted with Mycobacterium avium and Mycobacterium intracellulare in both an elisa and immunoblot. The recombinant protein also reacted with polyclonal sera produced in rabbits against all three mycobacteria, indicating the presence of cross-reactive epitopes in the protein. To determine the reactivity of cattle sera against epitopes recognised by the mAbs, competition assays between bovine sera and the mAbs were carried out. Two mAbs were significantly inhibited by sera from cattle that were naturally infected with M paratuberculosis. The results indicate that epitopes on the carboxyl terminus of the 34 kDa protein common to M paratuberculosis, M avium and M intracellulare readily induce antibody production in naturally infected cattle. These epitopes reduce the diagnostic specificity of the carboxyl terminus of the 34 kDa protein, which was originally thought to contain only M paratuberculosis-specific epitopes.

Development of an immunochromatographic test kit for rapid detection of bovine viral diarrhea virus antigen

An immunochromatographic test was developed for rapid diagnosis of bovine viral diarrhea virus (BVDV) infections using monoclonal antibodies against the nonstructural protein, NS3, of the virus. The kit detected specifically the NS3 of various BVDV strains. Using the kit, leukocyte extracts of cattle infected persistently with BVDV were found positive while those of healthy cattle were negative. The sensitivity and specificity of this kit in compared with virus isolation were 100% and 97.2%, respectively. Furthermore, the test also gave positive results for calves infected acutely with BVDV in experimental infection. The BVDV antigen was detected in 1 ml of blood using a relatively simple procedure. This test kit should be useful for rapid diagnosis of BVD.

Pathogenicity of a highly pathogenic avian influenza virus, A/chicken/Yamaguchi/7/04 (H5N1) in different species of birds and mammals

Outbreaks of highly pathogenic avian influenza (HPAI) have been occurring in domestic poultry in Asia since 1996. In the beginning of 2004, HPAI outbreaks were caused by H5N1 virus in two farms and a group of pet chickens in different areas of Japan. In the present study, the pathogenicity of A/chicken/Yamaguchi/7/04 (H5N1), which had been isolated from a dead chicken during the first outbreak in Japan, was assessed in chickens, quails, budgerigars, ducklings, mice, and miniature pigs by experimental infection. The virus was highly pathogenic to all the birds tested. Mice were susceptible to infection with a low mortality rate and miniature pigs were resistant to infection with the virus.

Library of influenza virus strains for vaccine and diagnostic use against highly pathogenic avian influenza and human pandemics

To prepare for the emergence of pandemic influenza in birds and mammals including humans, we have carried out global surveillance of avian influenza. Influenza A viruses of 48 combinations of 15 HA and 9 NA subtypes out of 135 theoretical combinations have been isolated from faecal samples of ducks in Alaska, Siberia, Mongolia, Taiwan, China and Japan. So far, viruses of 73 other combinations have been generated by genetic reassortment in chicken embryos. Thus, avian influenza viruses of 121 combinations of HA and NA subtypes have been stocked for use in vaccine and diagnosis. Their pathogenicity, antigenicity, genetic information, and yield in chicken embryo have been analysed and registered in the database.

Whether or not prophylactic excision of the extrahepatic bile duct is appropriate for patients with pancreaticobiliary maljunction without bile duct dilatation

BACKGROUND/AIMS

The standard treatment for patients with a pancreaticobiliary maljunction (PBM) without bile duct dilatation remains controversial.

METHODOLOGY

We followed up 29 patients with such PBM who mainly underwent a cholecystectomy alone. The ages of the patients ranged from 3 to 76 years (average age 47.3 years) and the ratio of males to females was 8 vs. 21. When the diameter of the common bile duct was less than 10mm, such bile ducts were diagnosed to have no dilatation. The main clinical indications for surgery were cholecystolithiasis in 15 patients, choledocholithiasis in 3, cholecystocholedocholithiasis in 2, gallbladder polyp in 2, adenomyomatosis in 2, cholecystitis in 2, and protein plug in 1.

RESULTS

The amylase levels of gallbladder bile in 20 patients ranged from 115 to 460,200 IU/mL (a mean of 191,698 IU/mL). One patient died of gastric cancer 182 months after surgery and two patients died of other diseases 153, 171 months after surgeries, respectively. The remaining 26 patients have all been doing well for 36 months to 326 months after surgery (a median follow-up period, 160.5 months). The 10- and 15-year survival rates were 100% and 89.7%.

CONCLUSIONS

In conclusion, a prophylactic resection of the extrahepatic bile duct and biliary diversion could be unnecessary for patients with PBM without bile duct dilatation.

Genetic recombination at different points in the Npro-coding region of bovine viral diarrhea viruses and the potentials to change their antigenicities and pathogenicities

Cytopathogenic (cp) bovine viral diarrhea virus (BVDV) strain KS86-1 cp was isolated from a cow persistently infected with non-cytopathogenic (ncp) BVDV strain KS86-ncp after development of mucosal disease by superinfection with cp BVDV strain Nose. cp BVDV strains 799cp and 839cp were also isolated from independent cattle that developed mucosal disease by superinfection with cp BVDV KS86-1cp. In the present study, genetic analysis revealed that the genes of cp BVDV strains 799cp and 839cp were chimeras between the genes of the persisting ncp BVDVs and that of superinfecting KS86-1cp. The genetic recombination that generates 799cp occurred between the identical points in the N(pro) gene region, whereas genetic recombination that generates 839cp occurred between different points in the N(pro) gene region. Both 799cp and 839cp were inherited Jiv gene of KS86-1cp strain and envelope protein genes of the persisting viruses. In addition, neutralization test disclosed that antigenicities of 799cp, 839cp, and KS86-1cp were also similar to each persisting virus. These findings indicate that exogenous cp BVDV containing insertion of Jiv gene in the 5 terminal region can induce genetic recombination with the original ncp BVDV at different points in the N(pro) gene region, and those viruses have high potential to change those antigenicities and pathogenicities by RNA recombination.

Pathogenicity of H5 influenza viruses for ducks

Four H5N1 highly pathogenic avian influenza (HPAI) viruses and an avirulent reassortant H5N1 virus were tested for their pathogenicity in domestic ducks. A/chicken/Yamaguchi/7/04 (H5N1) (Ck/Yamaguchi/04) isolated from a dead bird during the HPAI outbreak in Japan and A/duck/Yokohama/aq-10/03 (H5N1) (Dk/Yokohama/03) isolated from duck meat at a quarantine inspection for importation from China replicated in multiple organs including the brain of ducks. The ducks infected with Ck/Yamaguchi/04 did not show any clinical signs, while those infected with Dk/Yokohama/03 showed neurological signs. The ducks infected either with A/Hong Kong/483/97 (H5N1) or A/tern/South Africa/61 (H5N3), or with an avirulent H5N1 reassortant, did not show any clinical signs. Virus-specific antibodies were detected in the sera of the ducks infected with each of the five strains tested, indicating that all of the viral strains infected and replicated in the birds. Dk/Yokohama/03 grew in multiple organs more rapidly than did Ck/Yamaguchi/04. Considerable titers of virus were detected in the brain of the ducks infected with Dk/Yokohama/03 and these birds showed neurological signs. The present results demonstrate that the pathogenicity of influenza viruses for ducks does not correlate with that for chickens and that replication of the virus in the brain is critical for ducks to show neurological signs.

Co-infection of Staphylococcus aureus or Haemophilus paragallinarum exacerbates H9N2 influenza A virus infection in chickens

H9N2 influenza viruses are frequently isolated from chicken meat and bone marrow imported from China to Japan since 2001. These isolates were experimentally inoculated into specific pathogen-free chickens intranasally. Viruses were recovered from the meat and bone marrow of birds showing no overt signs. On the other hand, chickens co-infected with H9N2 virus and either Staphylococcus aureus or Haemophilus paragallinarum showed clinical signs severer than those shown by birds infected only with the virus alone or each of the bacteria alone. In addition, H9N2 viruses were more efficiently recovered from the chickens co-infected with S. aureus or H. paragallinarum than those from the birds infected with only the virus. The present results indicate that co-infection of H9N2 influenza virus with S. aureus or H. paragallinarum enhances the replication of the virus in chickens, resulting in exacerbation of the H9N2 virus infection.

The vagus nerve is one route of transneural invasion for intranasally inoculated influenza a virus in mice

Intranasally inoculated neurotropic influenza viruses in mice infect not only the respiratory tract but also the central nervous system (CNS), mainly the brain stem. Previous studies suggested that the route of invasion of virus into the CNS was via the peripheral nervous system, especially the vagus nerve. To evaluate the transvagal transmission of the virus, we intranasally inoculated unilaterally vagectomized mice with a virulent influenza virus (strain 24a5b) and examined the distribution of the viral protein and genome by immunohistochemistry and in situ hybridization over time. An asymmetric distribution of viral antigens was observed between vagal (nodose) ganglia: viral antigen was detected in the vagal ganglion of the vagectomized side 2 days later than in the vagal ganglion of the intact side. The virus was apparently transported from the respiratory mucosa to the CNS directly and decussately via the vagus nerve and centrifugally to the vagal ganglion of the vagectomized side. The results of this study, thus, demonstrate that neurotropic influenza virus travels to the CNS mainly via the vagus nerve.

Persistence of viral RNA segments in the central nervous system of mice after recovery from acute influenza A virus infection

One-hundred thirty-seven BALB/c mice were intranasally inoculated with neurotropic avian influenza A virus (H5N3). Thirty-nine of these mice died within 16 days post-inoculation (PID) and 98 of the mice recovered from the infection. To investigate whether viral antigens and genomes persist in the central nervous system (CNS) of recovered mice, immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) methods were performed. Histopathologically, mild interstitial pneumonia and non-suppurative encephalomyelitis restricted to the basal part of the frontal lobe of the cerebrum, brain stem and thoracic spinal cord were observed in BALB/c mice until 40 PID. Small amounts of viral antigens were detected in the brain and spinal cord and some viral RNA segments (NA, NP, M, PA, HA, NS, PB1) were intermittently detected in the CNS until 48 PID. Immunosuppression of these mice by dexamethazone (DEX) treatment did not increase the frequency of detection of the lesions, viral antigens or genomes. These findings suggest that viral genomes of neurovirulent influenza virus persist with restricted transcriptive activity in the CNS of the mice even after clinical recovery from the infection.

Induction of interferon-inducible protein-10 and monokine induced by interferon-gamma from human endothelial cells infected with Influenza A virus

Primary human umbilical vein endothelial cells (HUVECs) were infected with Influenza virus A/Aichi/2/68 (H3N2) in order to determine the role of endothelial cells in mediating inflammation induced upon virus infection. Structural proteins of the virus and mRNA of the M2 protein were detected in the infected cells, indicating that virus infection had occurred in HUVECs. The Influenza A virus-infected HUVECs showed elevated levels of gene expression of interferon (IFN)-inducible protein (IP)-10 and monokine induced by IFN-gamma (Mig), while heat-, formalin- and diethyl ether-inactivated viruses did not enhance the IP-10 and Mig gene expression. The results thus indicate that infection of live Influenza A virus is responsible for elevation of IP-10 and Mig gene expression. The elevation of IP-10 and Mig gene expression in infected HUVECs was not accompanied by the elevation of IFN-gamma gene expression, indicating that the elevation of IP-10 and Mig gene expression was independent of the IFN-gamma pathway.