Social isolation shortens lifespan through oxidative stress in ants.

Social isolation negatively affects health, induces detrimental behaviors, and shortens lifespan in social species. Little is known about the mechanisms underpinning these effects because model species are typically short-lived and non-social. Using colonies of the carpenter ant Camponotus fellah, we show that social isolation induces hyperactivity, alters space-use, and reduces lifespan via changes in the expression of genes with key roles in oxidation-reduction and an associated accumulation of reactive oxygen species. These physiological effects are localized to the fat body and oenocytes, which perform liver-like functions in insects. We use pharmacological manipulations to demonstrate that the oxidation-reduction pathway causally underpins the detrimental effects of social isolation on behavior and lifespan. These findings have important implications for our understanding of how social isolation affects behavior and lifespan in general.

Novelty-induced memory consolidation is accompanied by increased Agap3 transcription: a cross-species study.

Novelty-induced memory consolidation is a well-established phenomenon that depends on the activation of a locus coeruleus-hippocampal circuit. It is associated with the expression of activity-dependent genes that may mediate initial or cellular memory consolidation. Several genes have been identified to date, however, to fully understand the mechanisms of memory consolidation, additional candidates must be identified. In this cross-species study, we used a contextual novelty-exploration paradigm to identify changes in gene expression in the dorsal hippocampus of both mice and rats. We found that changes in gene expression following contextual novelty varied between the two species, with 9 genes being upregulated in mice and 3 genes in rats. Comparison across species revealed that ArfGAP with a GTPase domain, an ankyrin repeat and PH domain 3 (Agap3) was the only gene being upregulated in both, suggesting a potentially conserved role for Agap3. AGAP3 is known to regulate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptor trafficking in the synapse, which suggests that increased transcription of Agap3 may be involved in maintaining functional plasticity. While we identified several genes affected by contextual novelty exploration, we were unable to fully reverse these changes using SCH 23390, a dopamine D1/D5 receptor antagonist. Further research on the role of AGAP3 in novelty-induced memory consolidation could lead to better understanding of this process and guide future research.

Brain region networks for the assimilation of new associative memory into a schema.

Alterations in long-range functional connectivity between distinct brain regions are thought to contribute to the encoding of memory. However, little is known about how the activation of an existing network of neocortical and hippocampal regions might support the assimilation of relevant new information into the preexisting knowledge structure or 'schema'. Using functional mapping for expression of plasticity-related immediate early gene products, we sought to identify the long-range functional network of paired-associate memory, and the encoding and assimilation of relevant new paired-associates. Correlational and clustering analyses for expression of immediate early gene products revealed that midline neocortical-hippocampal connectivity is strongly associated with successful memory encoding of new paired-associates against the backdrop of the schema, compared to both (1) unsuccessful memory encoding of new paired-associates that are not relevant to the schema, and (2) the mere retrieval of the previously learned schema. These findings suggest that the certain midline neocortical and hippocampal networks support the assimilation of newly encoded associative memories into a relevant schema.

Dynamics of neuronal oscillations underlying nociceptive response in the mouse primary somatosensory cortex.

Pain is caused by tissue injury, inflammatory disease, pathogen invasion, or neuropathy. The perception of pain is attributed to the neuronal activity in the brain. However, the dynamics of neuronal activity underlying pain perception are not fully known. Herein, we examined theta-oscillation dynamics of local field potentials in the primary somatosensory cortex of a mouse model of formalin-induced pain, which usually shows a bimodal behavioral response interposed between pain-free periods. We found that formalin injection exerted a reversible shift in the theta-peak frequency toward a slower frequency. This shift was observed during nociceptive phases but not during the pain-free period and was inversely correlated with instantaneous pain intensity. Furthermore, instantaneous oscillatory analysis indicated that the probability of slow theta oscillations increased during nociceptive phases with an association of augmented slow theta power. Finally, cross-frequency coupling between theta and gamma oscillations indicated that the coupling peak frequency of theta oscillations was also shifted toward slower oscillations without affecting coupling strength or gamma power. Together, these results suggest that the dynamic changes in theta oscillations in the mouse primary somatosensory cortex represent the ongoing status of pain sensation.

Reimbursement pricing for new medical devices in Japan: Is the evaluation of innovation appropriate?

OBJECTIVES: In Japan, strong reimbursement pricing control measures for existing medical device products have rendered new medical device reimbursement pricing critical for manufacturers. Few studies have been conducted on this aspect; therefore, this paper (1) clarifies whether evaluation of innovation is appropriate or not and (2), if not, investigates its background. METHODS: In this research, 319 C1/C2 government decisions for new medical devices in the 10 years from April 2008 to March 2018 were analyzed. Evaluation of innovation was considered in terms of the reimbursement price, as well as the foreign average price ratio. RESULTS: Considering the degree of evaluation of innovation, the average premium rate for the similar function category comparison method was 10.2% during 2008 to 2010 (this means the newly set reimbursement price was 10.2% higher than that of corresponded exiting categories); it declined consistently thereafter, to 3.2% during 2016 to 2018. Moreover, evaluation of innovation by the foreign average price (FAP) ratio was 1.04 in 2008 to 2010, consistently decreasing to 0.88 in 2016 to 2018. The period from product approval to the non-Special Designated Treatment Material (non-STM) (a part of technical fee) price listing is much longer than that of the STM (own reimbursement price) listing. CONCLUSION: Several reasons were considered for the decline in innovation evaluation: (1) the lowering of the FAP upper limit ratio, (2) the possibility that there was not enough evidence at the time of price listing, (3) and the more rigorous standards to create a new separate functional category. However, some aspects were attributable to reimbursement system reform.

Microfluidic Long-Term Gradient Generator with Axon Separation Prototyped by 185 nm Diffused Light Photolithography of SU-8 Photoresist.

We have developed a cast microfluidic chip for concentration gradient generation that contains a thin (~5 µm² cross-sectional area) microchannel. The diffusion of diffused 185 nm ultraviolet (UV) light from an inexpensive low-pressure mercury lamp exposed a layer of the SU-8 photoresist from the backside and successfully patterned durable 2 µm-high microchannel mold features with smooth bell-shaped sidewalls. The thin channel had appropriate flow resistance and simultaneously satisfied both the rapid introduction of test substance and long-term maintenance of gradients. The average height and width at the half height of the channel, defined by a 2 µm-wide line mask pattern, were 2.00 ± 0.19 µm, and 2.14 ± 0.89 µm, respectively. We were able to maintain the concentration gradient of Alexa Fluor 488 fluorescent dye inside or at the exit of the thin microchannel in an H-shaped microfluidic configuration for at least 48 h. We also demonstrated the cultivation of chick embryo dorsal root ganglion neuronal cells for 96 h, and the directional elongation of axons under a nerve growth factor concentration gradient.

A case of perinatal hypophosphatasia with a novel mutation in the ALPL gene: clinical course and review of the literature.

Hypophosphatasia (HPP) is a metabolic bone disease characterized by failure of bone calcification and vitamin B6 dependent seizures. It is caused by loss-of-function mutations in the ALPL gene. A newborn girl required respiratory support by nasal-directional positive airway pressure at birth, and pyridoxine hydrochloride administration for vitamin B6-dependent seizures observed from day two. Umbilical cord blood showed low alkaline phosphatase (ALP) activity and high pyridoxal phosphate levels. Radiographs showed severe rickets-like appearance of the bones. Genetic analysis of the ALPL gene revealed compound heterozygous mutations, c.1559delT/p.Ser188Pro. We diagnosed her with perinatal severe HPP, and started the patient on asfotase alfa from day six. Following enzyme replacement therapy (ERT), skeletal mineralization and respiratory insufficiency improved with no remarkable side-effects. Crying vital capacity (CVC) was used to evaluate respiratory status, which continuously improved from 13.3 mL/kg (day 22) to 20.6 mL/kg (day 113). Since no seizures occurred, pyridoxine hydrochloride was tapered off at one year of age. Strategies to manage perinatal severe HPP cases following ERT have not been established till date. A review of the literature shows that CVC may be a good indicator for weaning from ventilatory support. In addition, ERT will most likely enable withdrawal of pyridoxine treatment.

Atrial Fibrillation Had Less Impact on the Risk of Ischemic Stroke in Non-anticoagulated Patients Undergoing Hemodialysis: Insight from the RAKUEN study.

Objective The progress of non-anticoagulated patients with atrial fibrillation (AF) undergoing hemodialysis has not been determined. Using data from the RAKUEN (Registry of Atrial fibrillation in chronic Kidney disease Under hEmodialysis from Niigata) study, we examined the clinical characteristics and outcomes among hemodialysis patients with AF who were not receiving a vitamin K antagonist (VKA). Methods and Results Forty-three of 423 patients undergoing hemodialysis (-10%) were prescribed a VKA. The remaining 380 patients (age 64.8±12.8 years, male 70%) were enrolled in the present study. During a mean observation period of 36 months, AF (n=55) was independently associated with all-cause death (hazard ratio, 1.82; 95% confidence interval, 1.12-2.94; p=0.014), but was not associated with ischemic stroke (hazard ratio, 1.91; 95% confidence interval, 0.74-4.92; p=0.177) and major bleeding (hazard ratio, 1.80; 95% confidence interval, 0.80-4.08; p=0.150). The crude incidence rates of all-cause death and ischemic stroke in the AF patients were 15.75 (2.5-fold higher compared to the non-AF patients) and 3.63 (1.7-fold higher compared to the non-AF patients) per 100 person-years, respectively. Conclusion A great impact on death, but not ischemic stroke, was observed in non-anticoagulated hemodialysis patients with AF in comparison to those without AF from the analysis of the RAKUEN study.

Hippocampal-prefrontal theta-gamma coupling during performance of a spatial working memory task.

Cross-frequency coupling supports the organization of brain rhythms and is present during a range of cognitive functions. However, little is known about whether and how long-range cross-frequency coupling across distant brain regions subserves working memory. Here we report that theta-slow gamma coupling between the hippocampus and medial prefrontal cortex (mPFC) is augmented in a genetic mouse model of cognitive dysfunction. This increased cross-frequency coupling is observed specifically when the mice successfully perform a spatial working memory task. In wild-type mice, increasing task difficulty by introducing a long delay or by optogenetically interfering with encoding, also increases theta-gamma coupling during correct trials. Finally, epochs of high hippocampal theta-prefrontal slow gamma coupling are associated with increased synchronization of neurons within the mPFC. These findings suggest that enhancement of theta-slow gamma coupling reflects a compensatory mechanism to maintain spatial working memory performance in the setting of increased difficulty.

Developmental Inhibition of Gsk3 Rescues Behavioral and Neurophysiological Deficits in a Mouse Model of Schizophrenia Predisposition.

While the genetic basis of schizophrenia is increasingly well characterized, novel treatments will require establishing mechanistic relationships between specific risk genes and core phenotypes. Rare, highly penetrant risk genes such as the 22q11.2 microdeletion are promising in this regard. Df(16)A(+/-) mice, which carry a homologous microdeletion, have deficits in hippocampal-prefrontal connectivity that correlate with deficits in spatial working memory. These mice also have deficits in axonal development that are accompanied by dysregulated Gsk3ß signaling and can be rescued by Gsk3 antagonists. Here we show that developmental inhibition of Gsk3 rescues deficits in hippocampal-prefrontal connectivity, task-related neural activity, and spatial working memory behavior in Df(16)A(+/-) mice. Taken together, these results provide mechanistic insight into how the microdeletion results in cognitive deficits, and they suggest possible targets for novel therapies.

Molecular substrates of altered axonal growth and brain connectivity in a mouse model of schizophrenia.

22q11.2 deletion carriers show specific cognitive deficits, and ∼30% of them develop schizophrenia. One of the disrupted genes is ZDHHC8, which encodes for a palmitoyltransferase. We show that Zdhhc8-deficient mice have reduced palmitoylation of proteins that regulate axonal growth and branching. Analysis of axonal projections of pyramidal neurons from both Zdhhc8-deficient and Df(16)A(+/-) mice, which model the 22q11.2 deletion, revealed deficits in axonal growth and terminal arborization, which can be prevented by reintroduction of active ZDHHC8 protein. Impaired terminal arborization is accompanied by a reduction in the strength of synaptic connections and altered functional connectivity and working memory. The effect of ZDHHC8 is mediated in part via Cdc42-dependent modulation of Akt/Gsk3ß signaling at the tip of the axon and can be reversed by pharmacologically decreasing Gsk3ß activity during postnatal brain development. Our findings provide valuable mechanistic insights into the cognitive and psychiatric symptoms associated with a schizophrenia-predisposing mutation.

Cuprizone short-term exposure: astrocytic IL-6 activation and behavioral changes relevant to psychosis.

A growing body of evidence suggests the involvement of inflammatory processes in the pathophysiology of schizophrenia. Four- to 8-week exposure to cuprizone, a copper chelator, causes robust demyelination and has been used to build a model for multiple sclerosis. In contrast, we report here the effects of 1-week cuprizone exposure in mice. This short-term cuprizone exposure elicits behavioral changes that include augmented responsiveness to methamphetamine and phencyclidine, as well as impaired working memory. The cellular effects of 1-week cuprizone exposure differ substantially from the longer-term exposure; perturbation of astrocytes and microglia is induced without any sign of demyelination. Furthermore, the proinflammatory cytokine interleukin-6 was significantly up-regulated in glial fibrillary acidic protein (GFAP)-positive cells. We propose that this cuprizone short-term exposure may offer a model to study some aspects of biology relevant to schizophrenia and related conditions.

Prenatal stress inhibits neuronal maturation through downregulation of mineralocorticoid receptors.

Prenatal stress (PS) increases the risk of depressive disorders in adult offspring. The pathophysiology of depressive disorders has been linked to hippocampal dysfunction; however, whether and how PS attenuates the development and function of hippocampal networks remains unknown. Using a rat model of PS, in which pregnant mothers receive daily restraint stress during late gestation and their offspring exhibit depressive-like behavior later in life, we show that PS impairs the morphological and functional maturation of hippocampal granule cells in adult offspring via the downregulated expression of mineralocorticoid receptors. PS reduced the dendritic complexity and spine density of neonatal-generated granule cells, which persists into adulthood. These granule cells exhibited depressed synaptic responses to stimulation of the medial perforant path. We further revealed that the expression of mineralocorticoid receptors, which we found is necessary for proper dendritic maturation in this study, was significantly downregulated in granule cells after PS. These results suggest that PS-induced downregulation of mineralocorticoid receptors attenuates neuronal maturation, which results in dysfunction of neuronal network in adulthood.

Influence of brain-derived neurotrophic factor on pathfinding of dentate granule cell axons, the hippocampal mossy fibers.

Mossy fibers, the dentate granule cell axons, are generated throughout an animal's lifetime. Mossy fiber paths and synapses are primarily restricted to the stratum lucidum within the CA3 region. Brain-derived neurotrophic factor (BDNF), a neurotrophin family protein that activates Trk neurotrophin receptors, is highly expressed in the stratum lucidum in an activity-dependent manner. The addition of a Trk neurotrophin receptor inhibitor, K252a, to cultured hippocampal slices induced aberrant extension of mossy fibers into ectopic regions. BDNF overexpression in granule cells ameliorated the mossy fiber pathway abnormalities caused by a submaximal dose of K252a. A similar rescue was observed when BDNF was expressed in CA3 pyramidal cells, most notably in mossy fibers distal to the expression site. These findings are the first to clarify the role of BDNF in mossy fiber pathfinding, not as an attractant cue but as a regulator, possibly acting in a paracrine manner. This effect of BDNF may be as a signal for new fibers to fasciculate and extend further to form synapses with neurons that are far from active BDNF-expressing synapses. This mechanism would ensure the emergence of new independent dentate gyrus-CA3 circuits by the axons of new-born granule cells.

Neuronal hyperactivity sustains the basal dendrites of immature dentate granule cells: time-lapse confocal analysis using hippocampal slice cultures.

Dendritic morphogenesis is an essential process for the establishment of proper neural circuitry. In the epileptic hippocampus, mature dentate granule cells (GCs) possess basal dendrites (BDs), which is abnormal and is assumed to contribute to seizure progression. However, there is a lack of direct time-lapse evidence showing that neuronal hyperactivity regulates the dendritic development of GCs. In the present study, we carried out time-lapse confocal analysis of the dendritic morphogenesis of GCs in hippocampal slice cultures that were prepared from postnatal 6-day-old (P6) rats. By electroporating membrane-targeted green fluorescent protein at 5 days in vitro (DIV), we found that most of the Prox1-positive and calbindin-negative immature GCs possessed several BDs and filopodia-rich apical dendrites at 7 DIV. BDs were gradually eliminated from 7 to 9 DIV, and they completely vanished at 14 DIV in all the GCs examined. However, most BDs failed to retract from 7 to 9 DIV, when the GABA(A) receptor antagonist picrotoxin was chronically applied to induce epileptic conditions in the cultures. These effects were blocked by coapplying tetrodotoxin, a sodium channel blocker, thus convincing us that neuronal hyperactivity contributes to the maintenance of BDs. Further, in the picrotoxin-treated cultures, most of the GCs persistently exhibited several BDs even after 14 DIV. In contrast, neither the progressive pruning of the filopodia nor the branch dynamics of the apical dendrites during the culture periods was affected by picrotoxin. These results, for the first time, provide us with direct evidence that neuronal hyperactivity contributes to the stability of pre-existing BDs.

Multiple bilateral coronary-biventricular fistulas with elevated left ventricular end-diastolic pressure.

Arterioventricular fistulas are relatively rare abnormalities and the etiology may be congenital or traumatic. We report a case of a 51-year-old woman in which all three coronary arteries emptied into both ventricles via multiple small fistulas resulting in elevated left ventricular end-diastolic pressure.

Systolic dysfunction in urban Japan.

BACKGROUND: Heart failure (HF), which can be caused by left ventricular systolic dysfunction (LVSD), is a growing problem in developed countries with a large aging population. The aim of the present study was to characterize outpatients with LVSD in the adult population (45-84 years) in an urban Japanese community (Niigata City), and delineate their characteristics in comparison with those in a rural one (Sado). METHODS AND RESULTS: Over a 5-year period, 1,297 patients (67% males) with LVSD (defined as ejection fraction < or =50%) were extracted from 87,953 echocardiography records available in 15 hospitals in Niigata City. The proportion of LVSD increased progressively with age (p-for-trend <0.0001), reaching 1-2% in those aged > or =75 years. The prevalence of comorbidities was noticeable (47% had hypertension, 41% myocardial ischemia, 34% atrial fibrillation, 33% previous hospitalization because of congestive HF, 27% cerebral stroke). In comparison with Sado, Niigata patients were younger, with a higher prevalence of comorbidities (hypertension, diabetes, dyslipidemia, and cerebral stroke). CONCLUSIONS: As the proportion of LVSD cases increases progressively with age, it is expected to simulate a future epidemic. The differences between patients' characteristics and disease patterns in urban and rural communities may favor individually tailoring preventive strategies for HF in these areas.

A low-cost method for brain slice cultures.

Low-cost, simple procedures for organotypic tissue cultures are desirable for high-throughput biological experiments such as large-scale medical/drug screening. We present a practical and economical method to cultivate brain slices using hydrophilic filtration membranes. With a cost reduction of more than 90%, this technique allows us to prepare hippocampal slice cultures that are morphologically and functionally indistinguishable from those obtained by the widely used Millicell-CM method.

Transient exposure of fibroblast growth factor-2 induced proliferative but not destructive changes in mouse knee joints.

Fibroblast growth factor-2 (FGF-2) has the potential to regenerate damaged articular cartilage tissue due to its exerting anabolic effects on chondrocytes. However, FGF-2 is involved in pathogenesis of rheumatoid arthritis, where the joint is destructed. The study aims at clarifying the effects of FGF-2 on joints. When radiolabeled FGF-2 was injected into knee joints of C57Bl/10 mice, a transient binding was observed in the superficial and intermediate zones of the articular cartilage as well as in the synovium and perichondrium. An FGF-2 injection (5 microg) caused synovial hyperplasia adjacent to the articular cartilage on day 7, cartilage formation adjacent to the articular cartilage on day 14, and osteophyte on day 21. The intensity of safranin-O staining of the articular cartilage increased on day 14. These changes were dose-dependent. No destructive changes in the joints were observed. In a joint, transient exposure of FGF-2 caused proliferative changes, but not destructive changes.