Effect of chronic administration of ostruthin on depression-like behavior in chronically stressed mice.

We have previously shown that a single dose of a TREK-1 channel activator, ostruthin, exhibited antidepressant and anxiolytic effects in acute behavioral test models in mice. To assess the potential clinical application, it is essential to evaluate the effects of long-term administration of ostruthin in a chronically stressed mouse model, which is considered to be similar to the clinical condition of major depression in humans. Here, we tested the effects of a single and a 7-day administration of ostruthin on mice that were subjected to chronic unpredictable mild stress (CUMS). A single administration of ostruthin showed antidepressive effects in the tail suspension and forced swim tests of CUMS-treated mice. Unexpectedly, the 7-day administration exhibited only insignificant antidepressive and anxiolytic effects. The 7-day regimen did not affect food intake or body-weight gain, suggesting the absence of apparent cytotoxicity. The mice receiving the 7-day administration had significantly lower blood concentrations of ostruthin compared to those receiving a single dose, suggesting an upregulation of drug-metabolizing activities. These findings suggest that there is a need for stable TREK-1 channel activators that are not affected by drug metabolism.

Single-Cell Labeling Strategies to Dissect Neuronal Structures and Local Functions.

The brain network consists of ten billion neurons and is the most complex structure in the universe. Understanding the structure of complex brain networks and neuronal functions is one of the main goals of modern neuroscience. Since the seminal invention of Golgi staining, single-cell labeling methods have been among the most potent approaches for dissecting neuronal structures and neural circuits. Furthermore, the development of sparse single-cell transgenic methods has enabled single-cell gene knockout studies to examine the local functions of various genes in neural circuits and synapses. Here, we review non-transgenic single-cell labeling methods and recent advances in transgenic strategies for sparse single neuronal labeling. These methods and strategies will fundamentally contribute to the understanding of brain structure and function.

Traditional Chinese medicine for promoting mental health of patients with COVID-19: a scoping review.

This study aimed to systematically review and depict the current studies of traditional Chinese medicine for the mental health of patients with coronavirus disease 2019 (COVID-19). Methods: A scoping review was conducted by searching PubMed, Web of Science, CNKI, Wanfang database, VIP database, and SinoMed, with the retrieval time being from the establishment of the database to April 18, 2022. The basic information of the included studies, objective, design, types of patients, interventions, outcomes, etc., was reviewed and summarized narratively. Methodological quality was assessed using the Cochrane Risk of Bias assessment tool, the methodological index for non-randomized studies or the Newcastle-Ottawa scale. Results: We identified 30 traditional Chinese medicine (TCM) studies from six databases. Among them, finished randomized controlled trials (n = 16) accounted for most of the studies, followed by single-arm studies (n = 9). In terms of study theme, 20 studies defined the mental health of patients with COVID-19 as the research theme. Psychological assessment was included in the inclusion criteria (performed before participation) of nine studies, whereas the other studies only mentioned the mental outcomes. TCM interventions included TCM exercises (Yijinjing, Baduanjin, Liuzijue, Taichi), acupoint stimulation (auricular and body points), moxibustion, decoction, or granules based on TCM syndrome differentiation, decoction, or granules with fixed formulae (Baidu Jieduan granules, Xuanfei Baidu decoction, and Qingfei Paidu decoction), Chinese patent medicine (Jinhua Qinggan granules), TCM psychological therapy (TCM ideological therapy, TCM five-tone therapy, and TCM psychological sand table), and TCM nursing (dialectical care, dialectical diet, and psychological counseling). Anxiety and depression were the main outcomes evaluated in regard to mental health in patients with COVID-19. The limitations of methodological quality were predominantly from follow-up, blinding, and registration. Positive results were reported by 27 studies (90%, n = 30). Conclusion: We summarized the existing literature about the impact of TCM on mental health in patients with COVID-19. The number of studies evaluating the impact of TCM on mental health is encouraging, but overall methodological quality was low. Several TCM interventions warrant further evaluation, particularly among populations outside of China, for the purpose of establishing supporting evidence. More importantly, research with stronger methodological quality needs to be developed. Graphical abstract: http://links.lww.com/AHM/A36.

Antidepressive effect of an inward rectifier K+ channel blocker peptide, tertiapin-RQ.

Renal outer medullary K+ channel, ROMK (Kir1.1, kcnj1) is expressed in the kidney and brain, but its role in the central nervous system remains unknown. Recent studies suggested an involvement of the ROMK channel in mental diseases. Tertiapin (TPN) is a European honey bee venom peptide and is reported to selectively block the ROMK channel. Here, we have chemically synthesized a series of mutated TPN peptides, including TPN-I8R and -M13Q (TPN-RQ), reported previously, and examined their blocking activity on the ROMK channel. Among 71 peptides tested, TPN-RQ was found to block the ROMK channel most effectively. Whole-cell patch-clamp recordings showed the essential roles of two disulfide bonds and the circular structure for the blockade activity. To examine the central role, we injected TPN-RQ intracerebroventricularly and examined the effects on depression- and anxiety-like behaviors in mice. TPN-RQ showed an antidepressive effect in tail-suspension and forced swim tests. The injection of TPN-RQ also enhanced the anxiety-like behavior in the elevated plus-maze and light/dark box tests and impaired spontaneous motor activities in balance beam and wheel running tests. Administration of TPM-RQ suppressed the anti-c-Fos immunoreactivity in the lateral septum, without affecting immunoreactivity in antidepressant-related nuclei, e.g. the dorsal raphe nucleus and locus coeruleus. TPN-RQ may exert its antidepressive effects through a different mechanism from current drugs.

The management of compensatory sweating after thoracic sympathectomy.

OBJECTIVE: The main therapeutic method of treatment for local hyperhidrosis is endoscopic thoracic sympathectomy. Generally, resections of the sympathetic trunk or ganglia are performed between the second rib and sixth rib. However, this procedure can result in compensatory sweating, in which excess sweating occurs on the back, chest, and abdomen. Compensatory sweating has been regarded as a thermoregulatory response and thought to be untreatable. This study suggests that compensatory sweating is not a physiologic reaction and is indeed treatable. METHODS: Eight patients with severe compensatory sweating were treated by observing blood perfusion of the skin with laser speckle flowgraphy, which determines the sympathetic nerves related to the area of skin with compensatory sweating. When intraoperative monitoring with laser speckle flowgraphy indicated the position of compensatory sweating by electrical stimulation of the sympathetic ganglion, ganglionectomy was performed. RESULTS: The skin domain that each sympathetic nerve controls was able to be detected by laser speckle flowgraphy. In all patients, compensatory sweating was resolved after interruption of the ganglia or sympathetic nerves related to compensatory sweating. CONCLUSIONS: Our results demonstrate that compensatory sweating is caused by denatured sympathetic nerves influenced by endoscopic thoracic sympathectomy and is not the result of a physiological response. With laser speckle flowgraphy, the sympathetic nerve related to the sweating of various parts of the body could be identified. The treatment of compensatory sweating on the back, chest, and stomach was previously considered to be difficult; however, compensatory sweating is demonstrated to be treatable with this technique.

Pore-forming spider venom peptides show cytotoxicity to hyperpolarized cancer cells expressing K+ channels: A lentiviral vector approach.

Recent studies demonstrated the upregulation of K+ channels in cancer cells. We have previously found that a pore-forming peptide LaFr26, purified from the venom of the Lachesana sp spider, was selectively incorporated into K+ channel expressing hyperpolarized cells. Therefore, it is expected that this peptide would have selective cytotoxicity to hyperpolarized cancer cells. Here we have tested whether LaFr26 and its related peptide, oxyopinin-2b, are selectively cytotoxic to K+ channel expressing cancer cells. These peptides were cytotoxic to the cells, of which resting membrane potential was hyperpolarized. The vulnerabilities of K+ channel-expressing cell lines correlated with their resting membrane potential. They were cytotoxic to lung cancer cell lines LX22 and BEN, which endogenously expressed K+ current. Contrastingly, these peptides were ineffective to glioblastoma cell lines, U87 and T98G, of which membrane potentials were depolarized. Peptides have a drawback, i.e. poor drug-delivery, that hinders their potential use as medicine. To overcome this drawback, we prepared lentiviral vectors that can express these pore-forming peptides and tested the cytotoxicity to K+ channel expressing cells. The transduction with these lentiviral vectors showed autotoxic activity to the channel expressing cells. Our study provides the basis for a new oncolytic viral therapy.

Antidepressive and anxiolytic effects of ostruthin, a TREK-1 channel activator.

We screened a library of botanical compounds purified from plants of Vietnam for modulators of the activity of a two-pore domain K+ channel, TREK-1, and we identified a hydroxycoumarin-related compound, ostruthin, as an activator of this channel. Ostruthin increased whole-cell TREK-1 channel currents in 293T cells at a low concentration (EC50 = 5.3 µM), and also activity of the TREK-2 channel (EC50 = 3.7 mM). In contrast, ostruthin inhibited other K+ channels, e.g. human ether-à-go-go-related gene (HERG1), inward-rectifier (Kir2.1), voltage-gated (Kv1.4), and two-pore domain (TASK-1) at higher concentrations, without affecting voltage-gated potassium channel (KCNQ1 and 3). We tested the effect of this compound on mouse anxiety- and depression-like behaviors and found anxiolytic activity in the open-field, elevated plus maze, and light/dark box tests. Of note, ostruthin also showed antidepressive effects in the forced swim and tail suspension tests, although previous studies reported that inhibition of TREK-1 channels resulted in an antidepressive effect. The anxiolytic and antidepressive effect was diminished by co-administration of a TREK-1 blocker, amlodipine, indicating the involvement of TREK-1 channels. Administration of ostruthin suppressed the stress-induced increase in anti-c-Fos immunoreactivity in the lateral septum, without affecting immunoreactivity in other mood disorder-related nuclei, e.g. the amygdala, paraventricular nuclei, and dorsal raphe nucleus. Ostruthin may exert its anxiolytic and antidepressive effects through a different mechanism from current drugs.

Sympathetic ganglionectomy for facial blushing using application of laser speckle flow graph.

OBJECTIVE: Endoscopic thoracic sympathectomy at the second rib level is considered effective as a therapeutic treatment for facial blushing. However, 10% to 15% of patients do not benefit from this intervention. No additional procedure has been developed for this disorder. Recently, ganglionectomy using application of laser speckle flow graph has been evaluated for the treatment of compensatory sweating. We report our results of ganglionectomy for facial blushing as a redo surgery. METHODS: Between August 2012 and April 2017, 8 patients with facial blushing who underwent an initial sympathectomy reported symptom recurrence. Seven patients had undergone transection of the sympathetic trunk at the second rib and 1 patient had undergone transection of the sympathetic trunk at the second and third ribs. These patients were treated using ganglionectomy guided by application of laser speckle flow graph. After temporary decreases in facial skin blood perfusion were confirmed by stimulating the sympathetic ganglions, ganglionectomy was performed. RESULTS: All patients' symptoms improved. There were no side effects, including deterioration of compensatory sweating, worsening of gustatory sweating, or Horner syndrome. There were no cases of mortality or conversion to open surgery. CONCLUSIONS: This study shows the effectiveness of ganglionectomy for the treatment of facial blushing, representing a new treatment option for this condition. Considering the mechanism of facial blushing, it is important to recognize that ganglionectomy is effective after the interception of the sympathetic trunk on the cranial side.

A New Device of Needlescopic Thoracic Sympathectomy Through a Skin Incision.

We describe a new technique of performing sympathectomy with a new device. A single skin incision 3 mm long was made in the armpit. The device enables complete resection of the sympathetic segment through a single skin incision, whereas sympathectomy is limited by the use of the conventional needle technique. Even if sympathetic nerves and blood vessels were overlapping, separation of the two organs was performed safely. This device increases the possibility of planning surgical procedures for patients with difficult anatomies.

Involvement of intracellular transport in TREK-1c current run-up in 293T cells.

The TREK-1 channel, the TWIK-1-related potassium (K+) channel, is a member of a family of 2-pore-domain K+ (K2P) channels, through which background or leak K+ currents occur. An interesting feature of the TREK-1 channel is the run-up of current: i.e. the current through TREK-1 channels spontaneously increases within several minutes of the formation of the whole-cell configuration. To investigate whether intracellular transport is involved in the run-up, we established 293T cell lines stably expressing the TREK-1c channel (K2P2.1) and examined the effects of inhibitors of membrane protein transport, N-methylmaleimide (NEM), brefeldin-A, and an endocytosis inhibitor, pitstop2, on the run-up. The results showing that NEM and brefeldin-A inhibited and pitstop2 facilitated the run-up suggest the involvement of intracellular protein transport. Correspondingly, in cells stably expressing the mCherry-TREK-1 fusion protein, NEM decreased and pitstop2 increased the cell surface localization of the fusion protein. Furthermore, the run-up was inhibited by the intracellular application of a peptide of the C-terminal fragment TREK335-360, corresponding to the interaction site with microtubule-associated protein 2 (Mtap2). This peptide also inhibited the co-immunoprecipitation of Mtap2 with anti-mCherry antibody. The extracellular application of an ezrin inhibitor (NSC668394) also suppressed the run-up and surface localization of the fusion protein. The co-application of these inhibitors abolished the TREK-1c current, suggesting that the additive effects of ezrin and Mtap2 enhance the surface expression of TREK-1c channels and the run-up. These findings clearly showed the involvement of intracellular transport in TREK-1c current run-up and its mechanism.

Increase in the titer of lentiviral vectors expressing potassium channels by current blockade during viral vector production.

BACKGROUND: High titers of lentiviral vectors are required for the efficient transduction of a gene of interest. During preparation of lentiviral the vectors, the protein of interest is inevitably expressed in the viral vector-producing cells. This expression may affect the production of the lentiviral vector. METHODS: We prepared lentiviral vectors expressing inwardly rectifying potassium channel (Lv-Kir2.1), its dominant-negative form (Lv-Kir-DN), and other K(+) channels, using the ubiquitously active ß-actin and neuron-specific synapsin I promoters. RESULTS: The titer of Lv-Kir-DN was higher than that of Lv-Kir2.1, suggesting a negative effect of induced K(+) currents on viral titer. We then blocked Kir2.1 currents with the selective blocker Ba(2+) during Lv-Kir2.1 production, and obtained about a 5-fold increase in the titer. Higher extracellular K(+) concentrations increased the titer of Lv-Kir2.1 about 9-fold. With a synapsin I promoter Ba(2+) increased the titer because of the moderate expression of Kir2.1 channel. Channel blockade also increased the titers of the lentivirus expressing Kv1.4 and TREK channels, but not HERG. The increase in titer correlated with the K(+) currents generated by the channels expressed. CONCLUSION: In the production of lentivirus expressing K(+) channels, titers are increased by blocking K(+) currents in the virus-producing cells. This identifies a crucial issue in the production of viruses expressing membrane channels, and should facilitate basic and gene therapeutic research on channelopathies.

A pore forming peptide from spider Lachesana sp. venom induced neuronal depolarization and pain.

BACKGROUND: Arachnoid venoms contain numerous peptides with ion channel modifying and cytolytic activities. METHODS: We developed a green fluorescent protein (GFP)-based assay that can monitor the changes in currents through overexpressed inwardly rectifying K(+) channels (Kir2.1), in which GFP expression was increased by blockade of Kir2.1 current. Using this assay, we screened venom of many spider species. A peptide causing GFP decreasing effect was purified and sequenced. Electrophysiological and pain-inducing effects of the peptide were analyzed with whole-cell patch-clamp recordings and hot-plate test, respectively. RESULTS: Among venoms we screened, soluble venom from Lachesana sp. decreased the GFP expression. Purification and sequencing of the peptide showed that the peptide is identical to a pore-forming peptide purified from Lachesana tarabaevi venom. Whole cell patch-clamp recordings revealed that the peptide had no effect on Kir2.1 current. Instead, it induced a current that was attributable to the pore-formation of the peptide. The peptide was selectively incorporated into hyperpolarized, i.e., Kir2.1 expressing, cells and for this reason the peptide decreased GFP expression in our Kir2.1 assay. The pore-formation positively shifted the reversal potential and induced burst firings in the hippocampal neurons in a synaptic current-independent way. The application of the Lachesana sp. peptide induced pain-related behavior in mice. CONCLUSIONS: The peptide, which was found in Lachesana sp. venom, formed pores and thereby depolarized neurons and induced pain. GENERAL SIGNIFICANCE: Our data suggested an additional physiological role of the pore-forming peptides.

The degradation of the inwardly rectifying potassium channel, Kir2.1, depends on the expression level: examination with fluorescent proteins.

The expression of ion channels is regulated by their synthesis as well as degradation, and some ion channels are degraded in an expression level-dependent way. Recently, new techniques of fluorescent proteins have been developed and seem to be useful to study protein degradation. To examine the regulation of the degradation of strongly inwardly rectifying potassium channel (Kir2.1) and the usefulness of the fluorescent proteins, we constructed Kir2.1 fusion proteins with SNAP tag and fluorescent timer (FT). The SNAP tag, which covalently binds to a specific membrane-permeable fluorescent dye, enables a pulse-chase experiment with fluorescence. When the SNAP-Kir2.1 proteins were expressed in 293T cells by low and high expression plasmids, the half-life of the fusion protein expressed by a high-expression plasmid was shorter (18.2±1.9 h) than that expressed by a low-expression plasmid (35.1+2.3h). The addition of Ba(2+), a selective blocker of Kir2.1, slowed the degradation, suggesting a current-dependency of degradation. Consistently, patch-clamp recording showed that cultivation in the presence of Ba(2+) increased the whole cell conductance of SNAP-Kir2.1. Since the fluorescence of FT changes gradually changes from green to red, the green/red ratio should allow us to monitor the changes in the degradation rate of FT-Kir2.1. Using this method, we confirmed the slower degradation by Ba(2+). The results suggest a homeostatic regulation of the degradation of Kir2.1 in the 293T cells, and the usefulness of fluorescence-based methods for examining the degradation of ion channels.

Lentiviral and Moloney retroviral expression of green fluorescent protein in somatotrophs in vivo.

Previous studies have shown that the locus control region (LCR) and the promoter of the growth hormone (GH) gene can control the expression of GH. Therefore, lenti- and retro-viral vectors with these elements might be useful to monitor the activation of the GH gene and the development of newborn somatotrophs. To test this, we first constructed a lentiviral vector, which expresses green fluorescent protein (GFP) under the control of these elements, and injected them into rat pituitaries in situ and in vivo. The lentiviral vector expressed GFP specifically in the anterior lobe, and nearly all GFP-positive cells were anti-GH immunoreactive. The GFP expression was upregulated by the administration of growth hormone releasing hormone and an IGF-1 receptor blocker. Furthermore, the social isolation stress, which was shown to decrease the GH secretion, decreased the GFP expression. Second, we injected the retroviral vector into neonatal rat pituitaries in vivo. At 30 days postinjection (DPI), almost all GFP-positive cells were anti-GH positive and anti-prolactin negative as the lentiviral expression. However, GFP was transiently expressed by developing lactotrophs at 8 and 16 DPI, suggesting that our vector lacks an element(s) which suppresses the expression. Meanwhile, the retrovirally labeled cells tended to cluster with the cells of same type. An analysis of cell numbers in each cluster revealed some features of cell proliferation. These viral vectors are shown to be useful tools to monitor the activation of the GH gene and the development of somatotrophs.

Clinical application of laser treatment for cardiovascular surgery.

BACKGROUND: Recently, several kinds of lasers have been widely employed in the field of medicine and surgery. However, laser applications are very rare in the field of cardiovascular surgery throughout the world. So, we have experimentally tried to use lasers in the field of cardiovascular surgery. There were three categories: 1) Transmyocardial laser revascularization (TMLR), 2) Laser vascular anastomosis, and 3) Laser angioplasty in the peripheral arterial diseases. By the way, surgery for ischemic heart disease has been widely performed in Japan. Especially coronary artery bypass grafting (CABG) for these patients has been done as a popular surgical method. Among these patients there are a few cases for whom CABG and percutaneous coronary intervention (PCI) could not be carried out, because of diffuse stenosis and small caliber of coronary arteries. Materials and methods of TMLR: A new method of tranasmyocardial revascularization by CO2 laser (output 100 W, irradiation time 0.2 sec) was experimentally performed to save severely ill patients. In this study, a feasibility of transmyocardial laser revascularization from left ventricular cavity through artificially created channels by laser was precisely evaluated. RESULTS: In trials on dogs laser holes 0.2mm in diameter have been shown microscopically to be patent even 3 years after their creation, thus this procedure could be used as a new method of transmyocardial laser revascularization. Clinical application of TMLR: Subsequently, transmyocardial laser revascularization was employed in a 55-year-old male patient with severe angina pectoris who had undergone pericardiectomy 7 years before. He was completely recovered from severe chest pain. Conclusions of TMLR: This patient was the first successful case in the world with TMLR alone. This method might be done for the patients who percutaneous coronary intervention and coronary artery bypass grafting could be carried out. Laser vascular anastomosis: At present time, in vascular surgery there are some problems to keep long-term patency after anastomosis of the conventional suture method, especially for small-caliber vessels. Materials and methods of Laser vascular anastomosis: From these standpoints, a low energy CO2 laser was employed experimentally in vascular anastomosis for small-caliber vessels. Resullts of Laser vascular anastomosis: From preliminary experiments it could be concluded that the optimal laser output was 20-40 mW and irradiation time was 6-12 sec/mm for vascular anastomosis of small-caliber vessels in the extremities. And then, histologic findings and intensity of the laser anastomotic sites were investigated thereafter. Subseqently, good enough intensity and good healing of laser anastomotic sites as well as the conventional suture method could be observed. There were no statistic differences between laser and suture methods. A feasibility of laser anastomosis could be considered and clinical application could be recognized. Clinical applications of Laser vascular anastomosis: On February 21, 1985, arterio-venous laser anastomosis for the patient with renal failure was smoothly done and she could accept hemodialysis. Conclusions of Laser vascular anastomosis: This patient was the first clinical successful case in the world. Thereafter, Laser vascular anastomosis were in 111 patients with intermittent claudication, refractory crural ulcer, and coronary disorders. Thereafter, they are going well. Laser angioplasty: Laser angioplasty for peripheral arterial diseases. There are many methods to treat peripheral arterial diseases such as balloon method, atherectomy, laser technique and stenting graft in the field of endovascular treatment. Recent years, minimal invasive treatment should be employed even in the surgical treatment. However, there are different images between these methods. Materials and methods of Laser angioplasty: We have chosen to use laser for endovascular treatment for peripheral arterial diseases. We have tried to check between laser energy and vessel wall. Results of Laser angioplasty: Subsequently, it could be concluded that optimal conditions for laser angioplasty were 6 W in output and irradiation time was 5 sec. And with another method of feedback control system, temperature of metal tip probe was 200°C and irradiation time was 5 sec for each shot. And histological study and feasibility of angioscopic guidance could be done and clinical application was started. Until now, 115 patients were successfully treated with their life longevity. Conclusions of Laser angioplasty: Thus, laser applications were useful methods to treat a lot of patients with some ischemic problems.

Voltage-dependent block by internal spermine of the murine inwardly rectifying K+ channel, Kir2.1, with asymmetrical K+ concentrations.

Effects of internal spermine on outward single-channel currents through a strongly inwardly rectifying K(+) channel (Kir2.1) were studied at asymmetrical K(+) concentrations (30 mm external and 150 mm internal K(+)). The current-voltage (I-V) relation for the single channel was almost linear and reversed at -37 ± 3 mV (V(R); n = 19). The channel conductance was 26.3 ± 1.3 pS (n = 24). The open-time and closed-time histograms were fitted with a single exponential function. Internal spermine at a concentration of 1-100 nm reduced the open time of the outward currents in a concentration-dependent manner and produced a blocked state. The steady-state open probability of the outward current decreased with larger depolarizations in both the absence and presence of internal spermine. The steady-state open probability with asymmetrical K(+) and symmetrical (150 mm external and internal K(+)) concentrations plotted against driving force (V - V(R)) coincided with smaller depolarizations in the absence of spermine and larger depolarizations and higher spermine concentrations in the presence of spermine. The blocking rate constants and unblock rates with 30 mm and 150 mm external K(+) were similar at the same driving force. The dissociation constant-membrane potential relation for 30 mm external K(+) was shifted in the negative direction from that for 150 mm external K(+) by 36 mV. These results suggested that the blocking kinetics depends on driving force to produce driving force-dependent inward rectification when the equilibrium potential for K(+) is altered by changing external K(+) and that the energy barriers and wells for blocking ions from passing or lodging are not stable but affected by external K(+) ions.

Genetically increased cell-intrinsic excitability enhances neuronal integration into adult brain circuits.

New neurons are added to the adult brain throughout life, but only half ultimately integrate into existing circuits. Sensory experience is an important regulator of the selection of new neurons but it remains unknown whether experience provides specific patterns of synaptic input or simply a minimum level of overall membrane depolarization critical for integration. To investigate this issue, we genetically modified intrinsic electrical properties of adult-generated neurons in the mammalian olfactory bulb. First, we observed that suppressing levels of cell-intrinsic neuronal activity via expression of ESKir2.1 potassium channels decreases, whereas enhancing activity via expression of NaChBac sodium channels increases survival of new neurons. Neither of these modulations affects synaptic formation. Furthermore, even when neurons are induced to fire dramatically altered patterns of action potentials, increased levels of cell-intrinsic activity completely blocks cell death triggered by NMDA receptor deletion. These findings demonstrate that overall levels of cell-intrinsic activity govern survival of new neurons and precise firing patterns are not essential for neuronal integration into existing brain circuits.

Aortocavitary fistula without aneurysm and transient incomplete atrioventricular block due to infective endocarditis.

A 67-year-old man with persistent fever and moderate aortic valve regurgitation was transferred. He suffered from incomplete atrioventricular block (AVB), and temporary pacing was needed. Left-to-right shunt flow from the aorta to the right atrium was found without an aneurysm. Operative findings indicated that the aortic valve was highly calcified. The orifice of an aortocavitary fistula (ACF) was detected in the sinus of Valsalva and the right atrium. Patch repair of the aortic annulus with complete débridement of the abscess cavity was performed, a procedure that consisted of aortic valve replacement directly to the Gore-Tex patch and aortic root replacement. His postoperative course was uneventful, but a pacemaker was implanted owing to complete AVB. To our knowledge, this is a rare case in which infective endocarditis was complicated by ACF without an aneurysm of the sinus of valsalva (SV) on the noncoronary cusp to the right atrium and transient incomplete AVB (Mobitz type II) occurring simultaneously.

Coronary artery bypass grafting with bilateral internal thoracic arteries for Bland-White-Garland syndrome in an adult.

A 46-year-old man with anomalous origin of the left coronary artery from the pulmonary artery (Bland-White-Garland syndrome) is reported. We successfully performed coronary artery bypass grafting with the use of bilateral internal thoracic arteries and ligation of the anomalous left coronary artery. The patient was discharged from the hospital after an uneventful postoperative course and postoperative coronary angiography, which revealed patent internal thoracic arteries and no leakage of blood flow from the anomalous left coronary artery to the pulmonary artery. This surgical procedure is technically simple and useful for adult patients with Bland-White-Garland syndrome. To our knowledge, this is one of only a few reports on coronary artery bypass grafting with bilateral internal thoracic arteries as a treatment of Bland-White-Garland syndrome.