Searching for new molecules involved in Anopheles mosquitoes' response to Plasmodium infection.

Plasmodium parasites within mosquitoes are exposed to various physiological processes, such as blood meal digestion activity, the gonotrophic cycle, and host responses preventing the entry of parasites into the midgut wall. However, when in vitro-cultured ookinetes are injected into the hemocoel of mosquitoes, Plasmodium parasites are not affected by the vertebrate host's blood contents and do not pass through the midgut epithelial cells. This infection method might aid in identifying mosquito-derived factors affecting Plasmodium development within mosquitoes. This study investigated novel mosquito-derived molecules related to parasite development in Anopheles mosquitoes. We injected in vitro-cultured Plasmodium berghei (ANKA strain) ookinetes into female and male Anopheles stephensi (STE2 strain) mosquitoes and found that the oocyst number was significantly higher in males than in females, suggesting that male mosquitoes better support the development of parasites. Next, RNA-seq analysis was performed on the injected female and male mosquitoes to identify genes exhibiting changes in expression. Five genes with different expression patterns between sexes and greatest expression changes were identified as being potentially associated with Plasmodium infection. Two of the five genes also showed expression changes with infection by blood-feeding, indicating that these genes could affect the development of Plasmodium parasites in mosquitoes.

Formation of free oocysts in Anopheles mosquitoes injected with Plasmodium ookinetes.

Malaria needs new strategies for its control. Plasmodium spp., the causative agent of malaria, is transmitted by mosquitoes. These parasites develop into oocysts and sporozoites in the body of the mosquitoes. A deeper understanding of oocysts that produce the infectious form of the parasite, sporozoites, can facilitate the development of novel countermeasures. However, the isolation of Plasmodium oocysts is challenging as these are formed between midgut epithelial cells and basal lamina after gametocytes enter the mosquito's body through blood feeding. Further research on oocysts has been impeded by issues related to oocyst isolation. Therefore, in this study, we injected Plasmodium into mosquitoes-an artificial and unique method-and aimed to clarify how oocysts were formed in mosquitoes after Plasmodium injection and whether free oocysts were formed from the mosquito tissue. Plasmodium berghei (ANKA strain) ookinetes cultured in vitro were injected into the thoracic body cavity (hemocoel) of female and male Anopheles stephensi mosquitoes. Oocysts were formed in the body of female and male mosquitoes at 14 days post injection. In addition, oocysts formed as a result of injection developed into sporozoites, which were infectious to mice. These findings suggest that P. berghei can complete its developmental stage in mosquitoes by injection. Some of the oocysts formed were free from mosquito tissue, and it was possible to collect oocysts with minimal contamination of mosquito tissue. These free oocysts can be used for investigating oocyst proteins and metabolism.

Olfactory marker protein contains a leucine-rich domain in the Ω-loop important for nuclear export.

Olfactory marker protein (OMP) is a cytosolic protein expressed in mature olfactory receptor neurons (ORNs). OMP modulates cAMP signalling and regulates olfactory sensation and axonal targeting. OMP is a small soluble protein, and passive diffusion between nucleus and cytoplasm is expected. However, OMP is mostly situated in the cytosol and is only sparsely detected in the nuclei of a subset of ORNs, hypothalamic neurons and heterologously OMP-expressing cultured cells. OMP can enter the nucleus in association with transcription factors. However, how OMP is retained in the cytosol at rest is unclear. Because OMP is proposed to affect cell differentiation, it is important to understand how OMP is distributed between cytoplasm and nucleus. To elucidate the structural profile of OMP, we applied several bioinformatics methods to a multiple sequence alignment (MSA) of OMP protein sequences and ranked the evolutionarily conserved residues. In addition to the previously reported cAMP-binding domain, we identified a leucine-rich domain in the Ω-loop of OMP. We introduced mutations into the leucine-rich region and heterologously expressed the mutant OMP in HEK293T cells. Mutations into alanine increased the nuclear distribution of OMP quantified by immunocytochemistry and western blotting. Therefore, we concluded that OMP contains a leucine-rich domain important for nuclear transport.

Olfactory marker protein is unlikely to be cleaved by calpain 5.

Olfactory maturation marker protein (OMP) is expressed in olfactory receptor neurons and hypothalamic neurons. OMP is a nested gene located in the intron of calpain 5 (CAPN5), a Ca2+-dependent cysteine protease. Despite being located at the same genomic locus, genetic regulation of the reciprocal expression of OMP and CAPN5 has been suggested. By performing a motif search, we detected possible calpain cleavage sites in OMP. However, the direct proteolytic regulation of OMP by CAPN5 is unclear. Here, we generated OMP fused with Myc-tag and His-tag at its N- and C-termini and examined whether CAPN5 cleaves OMP into fragments by detecting immunoreactivity against Myc, OMP and His. Western blotting demonstrated that OMP was unlikely to be cleaved even in the presence of Ca2+ in vitro. We expressed OMP and CAPN5 in HEK293T cells and applied a calcium ionophore under physiological conditions in cellulo, which resulted in no apparent fragmentation of OMP. We also applied liquid chromatography/mass spectrometry to the electrophoresed fractions smaller than the uncut Myc-OMP-His signals, which demonstrated no significant fragmentation of OMP. These results collectively indicate that OMP is unlikely to be cleaved by CAPN5.

Changes in postural sway during upright stance after short-term lower limb physical inactivity: A prospective study.

Previous studies have reported that motor behavior is affected by short-term physical inactivity using cast immobilization; however, the effects of inactivity on postural sway are not well-understood. This study aimed to investigate the effects of short-term lower limb disuse on postural sway in the upright position after cast removal. Twenty-two healthy young adults were enrolled, and each participant's lower limb on one side was fixed with a soft bandage and medical splint made from metal and soft urethane for 10 h. Fluctuations in the center of pressure (COP) were measured before and after immobilization; the total trajectory length, mean velocity, COP root mean square (RMS) area, mean medial-lateral (M-L) COP, and mean anterior-posterior (A-P) COP were selected as evaluation parameters. Compared with the postural sway before cast application, we noted an increase and shift (from the fixed to the nonfixed side) in the postural sway after cast removal. Our results therefore suggest that short-term disuse may cause acute changes in COP movements during quiet standing. Moreover, patients may maintain their standing posture by adopting a compensatory strategy involving lateral control, similar to individuals with stroke and patients who have undergone total knee arthroplasty.

Olfactory receptor 78 is expressed in hypothalamic vasopressin/oxytocin neurons, parenchymal microglia and choroidal macrophages in mice.

Olfactory receptors have been detected in extraolfactory organs. Olfactory receptor 78 (Olfr78), proposed to respond to small organic acids, is widely expressed in the kidney, arterioles, colon, and prostate. However, its expression patterns in the brain remain largely unknown. Using immunohistochemistry, we revealed that Olfr78 was densely expressed in the hypothalamus and choroid plexus and sparsely expressed throughout the parenchyma. By costaining with cellular markers, we further found that Olfr78 was expressed in the somata and axons of vasopressin/oxytocin neurons in the hypothalamic paraventricular/supraoptic nuclei. Olfr78 was also strongly expressed in macrophages in the choroid plexus and moderately expressed in microglia near the parenchymal vasculature. Considering that these brain regions should communicate with cerebral blood flow, Olfr78 could contribute to sensing the humoral conditions surrounding the cerebrovascular system.

PDGFRα+ subepithelial interstitial cells act as a pacemaker to drive smooth muscle of the guinea pig seminal vesicle.

Smooth muscle cells (SMCs) of the guinea pig seminal vesicle (SV) develop spontaneous phasic contractions, Ca2+ flashes and electrical slow waves in a mucosa-dependent manner, and thus it was envisaged that pacemaker cells reside in the mucosa. Here, we aimed to identify the pacemaker cells in SV mucosa using intracellular microelectrode and fluorescence Ca2+ imaging techniques. Morphological characteristics of the mucosal pacemaker cells were also investigated using focused ion beam/scanning electron microscopy tomography and fluorescence immunohistochemistry. Two populations of mucosal cells developed spontaneous Ca2+ transients and electrical activity, namely basal epithelial cells (BECs) and subepithelial interstitial cells (SICs). Pancytokeratin-immunoreactive BECs were located on the apical side of the basement membrane (BM) and generated asynchronous, irregular spontaneous Ca2+ transients and spontaneous transient depolarisations (STDs). The spontaneous Ca2+ transients and STDs were not diminished by 10 µM nifedipine but abolished by 10 µM cyclopiazonic acid (CPA). Platelet-derived growth factor receptor α (PDGFRα)-immunoreactive SICs were distributed just beneath the basal side of the BM and developed synchronous Ca2+ oscillations and electrical slow waves, which were suppressed by 3 µM nifedipine and abolished by 10 µM CPA. In SV mucosal preparations in which some smooth muscle bundles remained attached, SICs and residual SMCs developed temporally correlated spontaneous Ca2+ transients. Neurobiotin injected into SICs spread not only to neighbouring SICs but also to neighbouring SMCs or vice versa. These results suggest that PDGFRα+ SICs electrotonically drive the spontaneous contractions of SV smooth muscle. KEY POINTS: In many visceral smooth muscle organs, spontaneous contractions are electrically driven by non-muscular pacemaker cells. In guinea pig seminal vesicles (SVs), as yet unidentified mucosal cells appear to drive neighbouring smooth muscle cells (SMCs). Two populations of spontaneously active cells are distributed in the SV mucosa. Basal epithelial cells (BECs) generate asynchronous, irregular spontaneous Ca2+ transients and spontaneous transient depolarisations (STDs). In contrast, subepithelial interstitial cells (SICs) develop synchronous Ca2+ oscillations and electrical slow waves. Pancytokeratin-immunoreactive (IR) BECs are located on the apical side of the basement membrane (BM), while platelet-derived growth factor receptor α (PDGFRα)-IR SICs are located on the basal side of the BM. Spontaneous Ca2+ transients in SICs are synchronised with those in SV SMCs. Dye-coupling between SICs and SMCs suggests that SICs act as pacemaker cells to drive the spontaneous contractions of SV smooth muscle.

Conversion from dose length product to effective dose for the CT component of whole-body PET/CT.

OBJECTIVE: For dose management of CT, the ratio of effective dose (ED) to dose length product (DLP) is often used to convert DLP to ED. We evaluated this ratio in the CT component of whole-body PET/CT performed under various imaging conditions to determine a practical method for ED estimation applicable to PET/CT. METHODS: In total, 400 patients who underwent whole-body PET/CT were enrolled. The imaging conditions were variable in terms of the scanner model, setting of automatic exposure control (AEC) setting and arm positioning. The scan range was divided into six anatomical regions. DLP was calculated for each region, and multiplied by the conversion factor for the respective region to determine regional ED. The six regional EDs were summed together to determine ED by the regional DLP method (EDrDLP). Additionally, regional ED was assessed using CT-Expo, software dedicated to CT dose estimation, and the total of six regional EDs were defined as ED by the CT-Expo method (EDCT-Expo). EDrDLP/DLP and EDCT-Expo/DLP were calculated using DLP automatically provided by the scanner. RESULTS: EDrDLP/DLP ranged from 0.0121 to 0.0128 mSv/mGy/cm with the arms up and from 0.0127 to 0.0134 mSv/mGy/cm with the arms down. Putting the arms down slightly increased EDrDLP/DLP, presumably due to an increased contribution of the chest and abdomen to total radiation exposure. The AEC setting and scanner model also influenced EDrDLP/DLP significantly but slightly. EDCT-Expo/DLP showed apparent scanner dependence, which appeared mainly attributable to differences in the constants used for DLP calculation between the scanner and CT-Expo. CONCLUSION: Multiplication of scanner-derived DLP by a conversion factor of 0.013 mSv/mGy/cm provides acceptable ED estimates.

Clinical trials of Cry j 1 and Cry j 2 T-cell epitope peptide-expressing rice in patients with Japanese cedar pollinosis.

BACKGROUND: In allergic models, administration of rice that expresses a hybrid peptide consisting of 7 major T cell epitopes of Cry j 1 and Cry j 2 (7Crp), suppressed allergic symptoms, IgE elevation and specific T cell response to Japanese cedar pollen. OBJECTIVE: To evaluate the efficacy and safety of 7Crp-expressing rice in patients with Japanese cedar pollinosis. METHODS: A 24-week randomized, double-blind, placebo-controlled study was performed to see the efficacy of 7Crp on allergic symptoms using scoring systems, in which 45 patients were assigned to take either 5 g, 20 g test rice, or placebo daily. A 96-week open study was also conducted to determine its inhibitory effect on serum IgE and T cell proliferative response for Japanese cedar pollen, in which 10 patients consumed 5 g test rice daily. RESULTS: No adverse events associated with the test rice occurred, and the intake rate was more than 96%. The test rice did not show suppression of symptoms related to Japanese cedar pollinosis within 24 weeks. However, intake of 5 g test rice led to a significant decrease in T cell response to Japanese cedar pollen during and after the second disperse season in a 96-week open trial, whereas the specific IgE titer remained unchanged. CONCLUSIONS: Tolerability and safety of 7Crp-expressing rice was accepted. Daily intake of up to 20 g transgenic rice did not provide beneficial effects on Japanese cedar pollinosis within 24 weeks, however, continuous intake of 5 g rice might reduce allergen specific T cell response.

Evaluation of potential underuse of cardiac resynchronization therapy for heart failure with reduced ejection fraction.

BACKGROUND: The number of patients with chronic heart failure is increasing in Japan. However, the annual number of patients with heart failure who receive cardiac resynchronization therapy (CRT) has been constant in the last few years. In this study, we evaluated patients who did not receive CRT despite being eligible for this treatment to elucidate the clinical impact of CRT administration. METHODS: We assessed 214 patients with a left ventricular ejection fraction (LVEF) ≤ 50% (excluding patients treated with CRT) who underwent transthoracic echocardiography between January and May 2020 at our institution. The patients were stratified into two groups: Group A (n = 26; patients eligible for CRT) and Group B (n = 188; patients ineligible for CRT); however, all patients only received pharmacological therapy. We retrospectively analyzed the prognosis of these patients with respect to the cumulative number of hospitalizations for heart failure and cardiogenic deaths. RESULTS: We observed no significant between-group differences in age, sex, and severity/diagnosis of organic heart disease. Group A had a significantly higher number of hospitalizations for heart failure and cardiogenic deaths than Group B (log-rank test, P < .01; hazard ratio, 3.05; 95% confidence interval, 1.31-7.09; average follow-up period, 675 days). CONCLUSIONS: This study shows that 12% of patients were eligible for CRT. However, the implantation rate was low and no one was implanted. CRT is underutilized in patients who have heart failure with reduced LVEF. Therefore, we strongly recommend CRT for patients with indications for CRT.

Long-term oral administration of transgenic rice containing cedar pollen T-cell epitopes potentially improves medication- and allergy-related quality-of-life scores.

Background: We previously developed a transgenic rice that contains seven linked human predominant T-cell epitopes (7Crp) derived from Japanese cedar (JC) pollen allergens Cry j 1 and Cry j 2. Oral administration of 80 g of transgenic rice for 20 weeks suppressed allergen-specific T-cell proliferation in participants with JC pollinosis, but their clinical symptoms did not improve. Objective: We examined the clinical efficacy of low-dose (5 g and 20 g) intake of the transgenic rice administered for two successive seasons. Methods: In this randomized, double-blind, placebo controlled study, transgenic rice seeds (5 g or 20 g) were orally administered to the participants for 24 weeks in each of two successive JC pollen seasons. We analyzed T-cell proliferation and cytokine expression, and monitored symptom and medication scores during the pollen season. Quality of life (QOL) was evaluated by using the Japanese Allergic Rhinitis Quality of Life Standard Questionnaire (JRQLQ). Results: Specific T-cell proliferation after stimulation with 7Crp, Cry j 1, and Cry j 2 was significantly suppressed in the second JC pollen season. No significant differences were found among the three groups (5 g, 20 g, and placebo) with regard to clinical symptoms or medication scores in the first season. However, the medication scores and face scale for overall condition of JRQLQ improved in the 5-g transgenic rice group in the second season, although careful re-examination with a large sample size is necessary to confirm the results. Conclusion: Low-dose oral administration of transgenic rice that contains 7Crp significantly reduced allergen-specific T-cell responses and improved medication scores during the second season of administration. Thus, oral intake of the transgenic rice has the potential to induce immune tolerance to JC pollen allergens when administered for at least two successive seasons.

Polymorphic Ventricular Tachycardia with QT Interval Prolongation Due to a Brain Tumor.

We herein report the case of a 20-year-old man with a history of epilepsy who presented with frequent transient loss of consciousness (T-LOC) and polymorphic ventricular tachycardia (VT) with QT interval prolongation. Blood investigations revealed panhypopituitarism. Following a biopsy, he was diagnosed with brain germinoma. During the biopsy, he had an episode of polymorphous VT with QT prolongation. There was no recurrence of T-LOC following chemotherapy and hormone replacement therapy. This case indicates the importance of checking the QT interval in patients with T-LOC, including those with seizures and brain tumors, to ensure appropriate treatment.

Olfactory marker protein interacts with adenosine nucleotide derivatives.

Olfactory marker protein (OMP) is a genetic signature for mature olfactory receptor neurons (ORNs). Recently, it has been proposed that OMP directly captures odour-induced cAMP to swiftly terminate the olfactory signal transduction to maintain neuronal sensitivity. In the present study, we show that OMP can also interact with other adenosine nucleotides as ATP, ADP and AMP with different affinities. We performed bioluminescent resonant energy transfer (BRET) assay to measure the binding actions of the adenosine nucleotide derivatives in competition to cAMP. Amongst all, ATP showed the bell-shape affinity to OMP in the presence of cAMP; ADP and AMP showed fewer affinities to OMP than ATP. In the absence of cAMP analogues, ATP alone bound to OMP in a dose dependent manner with a lower affinity than to cAMP. Thus, OMP possessed different affinities to ATP in the presence or absence of cAMP. OMP may interact differentially with ATP and cAMP depending on its supply and demand along the cAMP-associated signalling in the limited spaces of cilia of ORNs.

Immunological and Symptomatic Effects of Oral Intake of Transgenic Rice Containing 7 Linked Major T-Cell Epitopes from Japanese Cedar Pollen Allergens.

BACKGROUND: A rice-based peptide vaccine containing 7 linked human predominant T-cell epitopes (7Crp) derived from Japanese cedar (JC) pollen allergens, Cry j 1 and Cry j 2, was developed. Here, we examined the efficacy and safety of this transgenic rice in JC pollinosis patients. METHODS: Transgenic rice (5, 20, and 80 g) was administered orally. We measured the T-cell proliferative activity against 7Crp, Cry j 1, and Cry j 2; the cytokine expression levels; and specific IgE and IgG4 production levels. In addition, the symptom and medication scores were monitored during the pollen season, and quality of life (QOL) was evaluated. RESULTS: T-cell proliferative activities to Cry j 1, Cry j 2, and 7Crp were significantly depressed in a dose-dependent manner. Oral intake of 80 g transgenic rice for 20 weeks resulted in significant suppression of allergen-specific T-cell proliferation with downregulation of IL-13 and upregulation of IL-10 levels but no changes to specific IgE and IgG4 levels. The QOL symptom scores for allergic rhinitis were not significantly improved. CONCLUSIONS: Allergen-specific T-cell responses were significantly reduced by oral intake of transgenic rice in a dose-dependent manner. However, neither medication score nor QOL symptom scores could be improved during the JC pollen season with oral intake of transgenic rice for 20 weeks.

SUBOPTIMAL MODULATION OF RADIATION DOSE IN THE COMPUTED TOMOGRAPHY COMPONENT OF WHOLE-BODY POSITRON EMISSION TOMOGRAPHY/COMPUTED TOMOGRAPHY.

Radiation exposure in computed tomography (CT) is automatically modulated by automatic exposure control (AEC) mainly based on scout images. To simulate the whole-body positron emission tomography/CT, CT images of a phantom were obtained using the posteroanterior scout image alone (PA scout) or the posteroanterior and lateral images (PA + Lat scout). Old and new versions of the AEC software were compared. Using the old version of the software and the PA scout, a markedly high dose at the top of the head was observed, which varied depending on the position of the phantom. This issue was resolved in the new version of the software. Radiation dose in the shoulder region was much higher using the PA scout than using the PA + Lat scout, even with the new version of the software. AEC may cause unreasonably high radiation exposure locally, and the appropriateness of the dose modulation pattern should be examined at each facility.

Olfactory marker protein contributes to the evaluation of odour values by olfactory glomerular processing.

Olfaction starts from olfactory receptor neurons (ORNs) that express olfactory marker protein (OMP). OMP deficit results in various behavioural phenotypes indicating olfactory dysfunction due to the impaired responses of ORNs. Recently, OMP was demonstrated to maintain strong olfaction by buffering olfactory cAMP signalling. However, the impact of OMP on olfaction behaviours, the assessment of which requires time to evaluate odour values, remains largely unexplained. Here, we examined the behaviour of heterozygous OMP+/GFP (HET) mice vs. homologous GFP-knock-in OMP-deficient OMP GFP/ GFP (KI) mice during the olfactory investigation of odours with different values. When a swab containing an organic odour was presented, both HET and KI mice swiftly approached and investigated the swab with gradual habituation over test sessions. However, when another similar odour was presented, KI mice investigated the new swab much less intensively than HET mice. Next, mice were placed in a chamber with an aversive odour source in one corner of a test chamber. KI mice more frequently approached the compartment containing the aversive odour source than HET mice. Finally, we trained mice to associate two odours with solutions by utilizing reward-penalty values. HET mice stayed close to the reward-associated odour, while KI mice initially approached the reward-associated odour, occasionally turned towards the penalty-associated odour source and eventually stayed in the reward-odour compartment. Histologically, c-Fos-expressing juxtaglomerular cells were fewer and more broadly distributed around glomeruli in KI mice than HET mice. In conclusion, OMP contributes to the evaluation of odour values by glomerular processing during an olfactory investigation task.

Virus database annotations assist in tracing information on patients infected with emerging pathogens.

The global pandemic of SARS-CoV-2 has disrupted human social activities. In restarting economic activities, successive outbreaks by new variants are concerning. Here, we evaluated the applicability of public database annotations to estimate the virulence, transmission trends and origins of emerging SARS-CoV-2 variants. Among the detectable multiple mutations, we retraced the mutation in the spike protein. With the aid of the protein database, structural modelling yielded a testable scientific hypothesis on viral entry to host cells. Simultaneously, annotations for locations and collection dates suggested that the variant virus emerged somewhere in the world in approximately February 2020, entered the USA and propagated nationwide with periodic sampling fluctuation likely due to an approximately 5-day incubation delay. Thus, public database annotations are useful for automated elucidation of the early spreading patterns in relation to human behaviours, which should provide objective reference for local governments for social decision making to contain emerging substrains. We propose that additional annotations for past paths and symptoms of the patients should further assist in characterizing the exact virulence and origins of emerging pathogens.

Comparison in Clinical Outcomes Between Leadless and Conventional Transvenous Pacemaker Following Transcatheter Aortic Valve Implantation.

OBJECTIVES: Atrioventricular block is a common complication of transcatheter aortic valve implantation (TAVI). Although conventional transvenous dual-chamber (DDD) pacemaker (PM) is ideal for atrioventricular block, leadless PM, which is less invasive, may be suitable for frail TAVI patients. Little is known about clinical outcomes of this newer device following TAVI. METHODS: A total of 330 consecutive patients undergoing TAVI were reviewed. Of these, PM cases without atrial fibrillation were studied. Indication for leadless PM was based on heart team discussion. RESULTS: PM implantations were performed in 30 patients (9.1%), and 24 patients (7.3%) had no atrial fibrillation. These 24 patients had 14 DDD-PMs and 10 leadless PMs, and formed the two study groups. Baseline characteristics were similar except for ejection fraction: median ages were 83.0 years (IQR, 81.0-87.0 years) vs 86.5 years (IQR, 83.5-90.3) (P=.18); 11 (78.6%) vs 8 (80%) were women (P=.67); Society of Thoracic Surgeons scores were 5.1% (IQR, 3.8%-5.9%) vs 5.3% (IQR, 3.4%-8.5%) (P=.82); and ejection fractions were 68.0% (IQR, 66.0%-70.5%) vs 59.0% (IQR, 52.8%-69.3%) (P=.049), for the DDD-PM and leadless PM groups, respectively. There was 1 case of atrial lead dislodgment in the DDD-PM group; otherwise, no complications related to the implantation procedure were found. The leadless PM group showed numerically shorter hospital stay: 12.5 days (range, 9.0-17.8 day) in the DDD-PM group vs 10.5 days (range, 7.8-15.3 days) in the leadless PM group (P=.44). Six-month follow-up revealed no significant differences in incidence of heart failure rehospitalizations or deaths: 2 (14.3%) in the DDD-PM group vs 2 (25%) in the leadless PM group (P=.47); and 2 (14.3%) in the DDD-PM group vs 0 (0%) in the leadless PM group (P=.39), respectively. CONCLUSIONS: Patients with leadless PM following TAVI may have shorter hospital stays, and clinical outcomes can be comparable with DDD-PMs. Leadless PMs may therefore be a reasonable option for frail TAVI patients.

Expression of the pacemaker channel HCN4 in excitatory interneurons in the dorsal horn of the murine spinal cord.

In the central nervous system, hyperpolarization-activated, cyclic nucleotide-gated (HCN1-4) channels have been implicated in neuronal excitability and synaptic transmission. It has been reported that HCN channels are expressed in the spinal cord, but knowledge about their physiological roles, as well as their distribution profiles, appear to be limited. We generated a transgenic mouse in which the expression of HCN4 can be reversibly knocked down using a genetic tetracycline-dependent switch and conducted genetically validated immunohistochemistry for HCN4. We found that the somata of HCN4-immunoreactive (IR) cells were largely restricted to the ventral part of the inner lamina II and lamina III. Many of these cells were either parvalbumin- or protein kinase Cγ (PKCγ)-IR. By using two different mouse strains in which reporters are expressed only in inhibitory neurons, we determined that the vast majority of HCN4-IR cells were excitatory neurons. Mechanical and thermal noxious stimulation did not induce c-Fos expression in HCN4-IR cells. PKCγ-neurons in this area are known to play a pivotal role in the polysynaptic pathway between tactile afferents and nociceptive projection cells that contributes to tactile allodynia. Therefore, pharmacological and/or genetic manipulations of HCN4-expressing neurons may provide a novel therapeutic strategy for the pain relief of tactile allodynia.