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Resume Le travail en equipe est defini par la multidisciplinarite : il regroupe des personnes de categories socioprofessionnelles, formations et origines differentes, reunies pour atteindre un objectif commun. Nous questionnons dans cet article la notion du « faire-equipe » dans le domaine de la recherche en sciences de la vie et de la sante, domaine ayant subi de profonds changements au cours des dernieres annees. En effet, la diminution des ressources financieres recurrentes, les pressions a la productivite, la precarisation de l’emploi et les echeances a court terme reduisant les delais d’execution des tâches interviennent a un moment ou les institutions de recherche insistent sur la valorisation des travaux effectues ; introduisant une forme d’injonction contradictoire. Dans ce contexte, la place de chacun au sein de l’equipe (responsabilites, prerogatives), les aspirations professionnelles (engagement, reconnaissance/visibilite, projection dans l’avenir) et la qualite des interactions humaines (confiance, solidarite, echanges) apparaissent destabilisees et mouvantes, affectant le sens meme du metier de chercheur. Nous proposons une vision ethique du « faire-equipe » qui pourrait permettre de retrouver le partage de visions convergentes au sein de l’equipe de recherche en limitant les effets nefastes resultant des processus organisationnels actuels. En redonnant du sens au travail mene par chacun des membres de l’equipe, une reflexion ethique sur le « faire-equipe » suscitera un mode de fonctionnement plus harmonieux de la recherche dans le domaine des sciences de la vie et de la sante.

Severe trauma can produce a postinjury “metabolic self-destruction” characterized by catabolic metabolism and hyperglycemia. The severity of the hyperglycemia is highly correlated with posttrauma morbidity and mortality. Although no mechanism has been posited to connect severe trauma with a loss of autonomic control over metabolism, traumatic injury causes other failures of autonomic function, notably, gastric stasis and ulceration (“Cushing’s ulcer”), which has been connected with the generation of thrombin. Our previous studies established that proteinase-activated receptors (PAR1; “thrombin receptors”) located on astrocytes in the autonomically critical nucleus of the solitary tract (NST) can modulate gastric control circuit neurons to cause gastric stasis. Hindbrain astrocytes have also been implicated as important detectors of low glucose or glucose utilization. When activated, these astrocytes communicate with hindbrain catecholamine neurons that, in turn, trigger counterregulatory responses (CRR). There may be a convergence between the effects of thrombin to derange hindbrain gastrointestinal control and the hindbrain circuitry that initiates CRR to increase glycemia in reaction to critical hypoglycemia. Our results suggest that thrombin acts within the NST to increase glycemia through an astrocyte-dependent mechanism. Blockade of purinergic gliotransmission pathways interrupted the effect of thrombin to increase glycemia. Our studies also revealed that thrombin, acting in the NST, produced a rapid, dramatic, and potentially lethal suppression of respiratory rhythm that was also a function of purinergic gliotransmission. These results suggest that the critical connection between traumatic injury and a general collapse of autonomic regulation involves thrombin action on astrocytes.

Description Cutaneous abscesses are collections of pus resulting from skin and soft tissue bacterial infections. They clinically exhibit the four cardinal inflammatory signs of pain, warmth, swelling, and erythema. In patients with darkly pigmented skin, classically-associated erythema may be challenging to appreciate and can lead to missed or delayed diagnosis. We compare abscess presentations in different skin types. Recognition of varying presentations of cutaneous abscesses in diverse skin colors will help clinicians utilize additional clues to identify and diagnose this entity correctly.

Description Recent studies estimate that more than 8 million Americans have psoriasis. The prevalence of psoriasis in African Americans is 1.5% compared to 3.6% of Caucasians. Psoriasis is likely to be underdiagnosed among African Americans and other individuals with darker pigmented skin due to variations in clinical presentation in addition to disease distribution and severity. We present images of psoriasis vulgaris in a variety of Fitzpatrick skin types. Differences in the biology of skin pigmentation may explain the clinical masking of erythema in darker-skinned individuals. Recognition of this important difference will help clinicians utilize additional clues to identify and diagnose this entity correctly.

Description Inverse psoriasis is a clinical variant of psoriasis involving flexural or intertriginous areas of the body. Inverse psoriasis may be present in 3 to 36% of psoriasis patients. Lesions are clinically characterized as smooth, well-demarcated, erythematous plaques (raised, >1 cm) without the typical silvery scales of classic psoriasis. Differential diagnosis includes tinea infection, candidiasis, seborrheic dermatitis, or bacterial streptococcal infection. The clinical images in this review focus on identifying inverse psoriasis along the full spectrum of skin tones.

Objective Postpartum hemorrhage is a leading cause of maternal morbidity and mortality worldwide. Institutions are encouraged to have a standardized approach to the management of obstetric hemorrhage. The purpose of this quality improvement project was to investigate postpartum hemorrhage associated morbidity before and after implementing an obstetric hemorrhage checklist-based protocol. Study design In 2015, a resident-driven initiative for obstetric hemorrhage was initiated at a single institution using a checklist-based protocol for postpartum hemorrhage. The project included development of the obstetric hemorrhage checklist by a multidisciplinary team and implementation using low cost education and training strategies. Following implementation, a pre-and post-protocol retrospective analysis was performed measuring maternal morbidity surrogates and protocol compliance. During the 18 month study period, 422 women were identified for review and 147 met criteria in the pre-protocol group and 150 met criteria in the post-protocol group. Results There was a significant decrease in severe postpartum hemorrhage rates in the post-protocol group (p = 0.04) and all other surrogates for maternal morbidity decreased in the post-protocol group. Protocol compliance was 62.2% and compliance with screening using an assessment of hemorrhage risk was 75.7%. Conclusion The implementation of a checklist-based management protocol for postpartum hemorrhage has shown a promising trend in improving maternal morbidity, screening, early diagnosis, and healthcare delivery for obstetric hemorrhage at our institution and has been approved for larger scale implementation within our health system.

ObjectiveA retrospective cohort study comparing survival and perioperative outcomes of patients with early vulvar cancer who underwent sentinel lymph node biopsy versus standard lymphadenectomyMethodsPatients diagnosed between January 2012 and December 2015 with vulvar squamous cell carcinoma of less than 4 cm in size, with invasion of at least 1 mm, who underwent sentinel lymph node biopsy, lymphadenectomy, or both were identified from the National Cancer Database. Overall survival was evaluated following generation of Kaplan-Meier curves and compared with the log-rank test for patients who had at least 1 month of follow-up. A Cox model was constructed to control for confounders.ResultsA total of 1583 patients were identified; 304 patients (19.2%) underwent sentinel lymph node biopsy alone. Sentinel lymph node biopsy utilization increased 13.9% between 2012 and 2015. Patients who underwent sentinel node biopsy alone were less likely to have comorbidities compared with those undergoing lymphadenectomy only or sentinel node biopsy with lymphadenectomy (25.3% vs 32.9% vs 31.9%, p=0.042), had smaller tumors (median 1.6 vs 2.0 vs 2.0 cm, pConclusionsThe utilization of sentinel lymph node biopsy is increasing in the management of vulvar cancer and is associated with superior perioperative outcomes without impacting overall survival.

Peripheral viscerosensory afferent signals are transmitted to the nucleus tractus solitarii (nTS) via release of glutamate. Following release, glutamate is removed from the extrasynaptic and synaptic cleft via excitatory amino acid transporters (EAATs), thus limiting glutamate receptor activation or over activation, and maintaining its working range. We have shown that EAAT block with the antagonist threo-β-benzyloxyaspartic acid (TBOA) depolarized nTS neurons and increased spontaneous excitatory postsynaptic current (sEPSC) frequency yet reduced the amplitude of afferent (TS)-evoked EPSCs (TS-EPSCs). Interestingly, chronic intermittent hypoxia (CIH), a model of obstructive sleep apnea (OSA), produces similar synaptic responses as EAAT block. We hypothesized EAAT expression or function are downregulated after CIH, and this reduction in glutamate removal contributes to the observed neurophysiological responses. To test this hypothesis, we used brain slice electrophysiology and imaging of glutamate release and TS-afferent Ca(2+) to compare nTS properties of rats exposed to 10 days of normoxia (Norm; 21%O(2)) or CIH. Results show that EAAT blockade with (3S)-3-[[3-[[4-(trifluoromethyl)benzoyl]-amino]phenyl]methoxy]-l-aspartic acid (TFB-TBOA) in Norm caused neuronal depolarization, generation of an inward current, and increased spontaneous synaptic activity. The latter augmentation was eliminated by inclusion of tetrodotoxin in the perfusate. TS stimulation during TFB-TBOA also elevated extracellular glutamate and decreased presynaptic Ca(2+) and TS-EPSC amplitude. In CIH, the effects of EAAT block are eliminated or attenuated. CIH reduced EAAT expression in nTS, which may contribute to the attenuated function seen in this condition. Therefore, CIH reduces EAAT influence on synaptic and neuronal activity, which may lead to the physiological consequences seen in OSA and CIH. NEW & NOTEWORTHY Removal of excitatory amino acid transporter (EAAT) restraint increases spontaneous synaptic activity yet decreases afferent [tractus solitarius (TS)]-driven excitatory postsynaptic current (EPSC) amplitude. In the chronic intermittent hypoxia model of obstructive sleep apnea, this restraint is lost due to reduction in EAAT expression and function. Thus EAATs are important in controlling elevated glutamatergic signaling, and loss of such control results in maladaptive synaptic signaling.

Hindbrain catecholaminergic (CA) neurons are required for critical autonomic, endocrine, and behavioral counterregulatory responses (CRRs) to hypoglycemia. Recent studies suggest that CRR initiation depends on hindbrain astrocyte glucose sensors (McDougal DH, Hermann GE, Rogers RC. Front Neurosci 7: 249, 2013; Rogers RC, Ritter S, Hermann GE. Am J Physiol Regul Integr Comp Physiol 310: R1102–R1108, 2016). To test the proposition that hindbrain CA responses to glucoprivation are astrocyte dependent, we utilized transgenic mice in which the calcium reporter construct (GCaMP5) was expressed selectively in tyrosine hydroxylase neurons (TH-GCaMP5). We conducted live cell calcium-imaging studies on tissue slices containing the nucleus of the solitary tract (NST) or the ventrolateral medulla, critical CRR initiation sites. Results show that TH-GCaMP5 neurons are robustly activated by a glucoprivic challenge and that this response is dependent on functional astrocytes. Pretreatment of hindbrain slices with fluorocitrate (an astrocytic metabolic suppressor) abolished TH-GCaMP5 neuronal responses to glucoprivation, but not to glutamate. Pharmacologic results suggest that the astrocytic connection with hindbrain CA neurons is purinergic via P2 receptors. Parallel imaging studies on hindbrain slices of NST from wild-type C57BL/6J mice, in which astrocytes and neurons were prelabeled with a calcium reporter dye and an astrocytic vital dye, show that both cell types are activated by glucoprivation but astrocytes responded significantly sooner than neurons. Pretreatment of these hindbrain slices with P2 antagonists abolished neuronal responses to glucoprivation without interruption of astrocyte responses; pretreatment with fluorocitrate eliminated both astrocytic and neuronal responses. These results support earlier work suggesting that the primary detection of glucoprivic signals by the hindbrain is mediated by astrocytes.

Mitochondria undergo continuous cycles of fission and fusion to promote inheritance, regulate quality control, and mitigate organelle stress. More recently, this process of mitochondrial dynamics has been demonstrated to be highly sensitive to nutrient supply, ultimately conferring bioenergetic plasticity to the organelle. However, whether regulators of mitochondrial dynamics play a causative role in nutrient regulation remains unclear. In this study, we generated a cellular loss-of-function model for dynamin-related protein 1 (DRP1), the primary regulator of outer membrane mitochondrial fission. Loss of DRP1 (shDRP1) resulted in extensive ultrastructural and functional remodeling of mitochondria, characterized by pleomorphic enlargement, increased electron density of the matrix, and defective NADH and succinate oxidation. Despite increased mitochondrial size and volume, shDRP1 cells exhibited reduced cellular glucose uptake and mitochondrial fatty acid oxidation. Untargeted transcriptomic profiling revealed severe downregulation of genes required for cellular and mitochondrial calcium homeostasis, which was coupled to loss of ATP-stimulated calcium flux and impaired substrate oxidation stimulated by exogenous calcium. The insights obtained herein suggest that DRP1 regulates substrate oxidation by altering whole-cell and mitochondrial calcium dynamics. These findings are relevant to the targetability of mitochondrial fission and have clinical relevance in the identification of treatments for fission-related pathologies such as hereditary neuropathies, inborn errors in metabolism, cancer, and chronic diseases.

Previous studies identify a role for hypothalamic glia in energy balance regulation; however, a narrow hypothalamic focus provides an incomplete understanding of how glia throughout the brain respond to and regulate energy homeostasis. We examined the responses of glia in the dorsal vagal complex (DVC) to the adipokine leptin and high fat diet-induced obesity. DVC astrocytes functionally express the leptin receptor; in vivo pharmacological studies suggest that DVC astrocytes partly mediate the anorectic effects of leptin in lean but not diet-induced obese rats. Ex vivo calcium imaging indicated that these changes were related to a lower proportion of leptin-responsive cells in the DVC of obese versus lean animals. Finally, we investigated DVC microglia and astroglia responses to leptin and energy balance dysregulation in vivo: obesity decreased DVC astrogliosis, whereas the absence of leptin signaling in Zucker rats was associated with extensive astrogliosis in the DVC and decreased hypothalamic micro- and astrogliosis. These data uncover a novel functional heterogeneity of astrocytes in different brain nuclei of relevance to leptin signaling and energy balance regulation.

Astrocytic excitatory amino acid transporters (EAATs) are critical to restraining synaptic and neuronal activity in the nucleus tractus solitarii (nTS). Relief of nTS EAAT restraint generates two opposing effects, an increase in neuronal excitability that reduces blood pressure and breathing and an attenuation in afferent [tractus solitarius (TS)]-driven excitatory postsynaptic current (EPSC) amplitude. Although the former is due, in part, to activation of ionotropic glutamate receptors, there remains a substantial contribution from another unidentified glutamate receptor. In addition, the mechanism(s) by which EAAT inhibition reduced TS-EPSC amplitude is unknown. Metabotropic glutamate receptors (mGluRs) differentially modulate nTS excitability. Activation of group I mGluRs on nTS neuron somas leads to depolarization, whereas group II/III mGluRs on sensory afferents decrease TS-EPSC amplitude. Thus we hypothesize that EAATs control postsynaptic excitability and TS-EPSC amplitude via restraint of mGluR activation. To test this hypothesis, we used in vivo recording, brain slice electrophysiology, and imaging of glutamate release and TS-afferent Ca2+. Results show that EAAT blockade in the nTS with (3 S)-3-[[3-[[4-(trifluoromethyl)benzoyl]amino]phenyl]methoxy]-l-aspartic acid (TFB-TBOA) induced group I mGluR-mediated depressor, bradycardic, and apneic responses that were accompanied by neuronal depolarization, elevated discharge, and increased spontaneous synaptic activity. Conversely, upon TS stimulation TFB-TBOA elevated extracellular glutamate to decrease presynaptic Ca2+ and TS-EPSC amplitude via activation of group II/III mGluRs. Together, these data suggest an important role of EAATs in restraining mGluR activation and overall cardiorespiratory function.

Astrocytes generate robust cytoplasmic calcium signals in response to reductions in extracellular glucose. This calcium signal, in turn, drives purinergic gliotransmission, which controls the activity of catecholaminergic (CA) neurons in the hindbrain. These CA neurons are critical to triggering glucose counter-regulatory responses (CRRs) that, ultimately, restore glucose homeostasis via endocrine and behavioral means. Although the astrocyte low-glucose sensor involvement in CRR has been accepted, it is not clear how astrocytes produce an increase in intracellular calcium in response to a decrease in glucose. Our ex vivo calcium imaging studies of hindbrain astrocytes show that the glucose type 2 transporter (GLUT2) is an essential feature of the astrocyte glucosensor mechanism. Coimmunoprecipitation assays reveal that the recombinant GLUT2 binds directly with the recombinant Gq protein subunit that activates phospholipase C (PLC). Additional calcium imaging studies suggest that GLUT2 may be connected to a PLC-endoplasmic reticular-calcium release mechanism, which is amplified by calcium-induced calcium release (CICR). Collectively, these data help outline a potential mechanism used by astrocytes to convert information regarding low-glucose levels into intracellular changes that ultimately regulate the CRR.

Die bronchoalveolare Lavage [BAL] ist ein wichtiger diagnostischer Standard in der Diagnosestellung zahlreicher Lungenerkrankungen. Einen besonderen Stellenwert hat sie insbesondere bei den entzundlichen und interstitiellen Lungenparenchymerkrankungen. Fragestellung Im Rahmen der Diagnosestellung des Lungenkarzinoms ist der Zusatznutzen einer Bronchiallavage unklar. Daten zu einem moglicherweise typischen Verteilungsmuster in der Differenzialzytologie und in den Lymphozytenpopulationen in der BAL bei Lungenkrebspatienten fehlen. Insbesondere vor dem Hintergrund der mittlerweile beim nicht kleinzelligen Lungenkarzinom fest etablierten immunonkologischen Therapien, konnte es jedoch fur das Nebenwirkungsmanagement dieser Therapie von Bedeutung sein, ob Lungenkarzinome aufgrund einer Immunaktivierung ein typisches Verteilungsmuster in der BAL-Differenzialzytologie verursachen. Methodik Im Rahmen einer Hypothesen-generierenden retrospektiven Analyse untersuchten wir das Verteilungsmuster in der Differenzialzytologie der BAL von Lungenkrebspatienten im Rahmen der Erstdiagnose. Dabei wurden die BAL-Befunde von 38 Patienten im Rahmen der Erstdiagnose eines Lungenkarzinoms erfasst und ausgewertet. Ergebnis Es konnte eine Tendenz zu erhohten CD25-Lymphozytenanteilen und eine Erhohung DR-positiver Lymphozyten festgestellt werden. Beide gelten als Marker der Lymphozytenaktivierung. Ein typisches Verteilungsmuster konnte weder in der Differenzialzytologie noch in der Verteilung der Lymphozytensubpopulationen festgestellt werden. Moglicherweise konnten Untersuchungen zu microRNA-Mustern in Zukunft spezifische Veranderungen bei Lungenkrebspatienten zeigen, die dann die Diagnostik in Erstdiagnose und Nachsorge unterstutzen.

Hindbrain astrocytes are emerging as critical components in the regulation of homeostatic functions by either modulating synaptic activity or serving as primary detectors of physiological parameters. Recent studies have suggested that the glucose counter-regulation response (CRR), a critical defense against hypoglycemic emergencies, is dependent on glucoprivation-sensitive astrocytes in the hindbrain. This subpopulation of astrocytes produces a robust calcium signal in response to glucopenic stimuli. Both ex vivo and in vivo evidence suggest that low-glucose sensitive astrocytes utilize purinergic gliotransmission to activate catecholamine neurons in the hindbrain that are critical to the generation of the integrated CRR. Lastly, reports in the clinical literature suggest that an uncontrolled activation of CRR may as part of the pathology of severe traumatic injury. Work in our laboratory also suggests that this pathological hyperglycemia resulting from traumatic injury may be caused by the action of thrombin (generated by tissue trauma or bleeding) on hindbrain astrocytes. Similar to their glucopenia-sensitive neighbors, these hindbrain astrocytes may trigger hyperglycemic responses by their interactions with catecholaminergic neurons.

Proinflammatory cytokines impact islet β-cell mass and function by altering the transcriptional activity within pancreatic β-cells, producing increases in intracellular nitric oxide abundance and the synthesis and secretion of immunomodulatory proteins such as chemokines. Herein, we report that IL-1β, a major mediator of inflammatory responses associated with diabetes development, coordinately and reciprocally regulates chemokine and insulin secretion. We discovered that NF-κB controls the increase in chemokine transcription and secretion as well as the decrease in both insulin secretion and proliferation in response to IL-1β. Nitric oxide production, which is markedly elevated in pancreatic β-cells exposed to IL-1β, is a negative regulator of both glucose-stimulated insulin secretion and glucose-induced increases in intracellular calcium levels. By contrast, the IL-1β-mediated production of the chemokines CCL2 and CCL20 was not influenced by either nitric oxide levels or glucose concentration. Instead, the synthesis and secretion of CCL2 and CCL20 in response to IL-1β were dependent on NF-κB transcriptional activity. We conclude that IL-1β-induced transcriptional reprogramming via NF-κB reciprocally regulates chemokine and insulin secretion while also negatively regulating β-cell proliferation. These findings are consistent with NF-κB as a major regulatory node controlling inflammation-associated alterations in islet β-cell function and mass.

Severe autonomic dysfunction, including the loss of control of the cardiovascular, respiratory, and gastrointestinal systems, is a common comorbidity of stroke and other bleeding head injuries. Previous studies suggest that this collapse of autonomic control may be caused by thrombin acting on astrocytic protease-activated receptors (PAR1) in the hindbrain. Using calcium imaging and electrophysiological techniques, we evaluated the mechanisms by which astrocytic PAR1s modulate the activity of presynaptic vagal afferent terminals and postsynaptic neurons in the rat nucleus of the solitary tract (NST). Our calcium-imaging data show that astrocytic and neuronal calcium levels increase after brain slices are treated with the PAR1 agonist SFLLRN-NH2. This increase in activity is blocked by pretreating the slices with the glial metabolic blocker fluorocitrate. In addition, PAR1-activated astrocytes communicate directly with NST neurons by releasing glutamate. Calcium responses to SFLLRN-NH2in the astrocytes and neurons significantly increase after bath application of the excitatory amino acid transporter blockerdl-threo-β-benzyloxyaspartic acid (TBOA) and significantly decrease after bath application of the NMDA receptor antagonistdl-2-amino-5-phosphonopentanoic acid (dl-AP5). Furthermore, astrocytic glutamate activates neuronal GluN2B-containing NMDA receptors. Voltage-clamp recordings of miniature EPSCs (mEPSCs) from NST neurons show that astrocytes control presynaptic vagal afferent excitability directly under resting and activated conditions. Fluorocitrate significantly decreases mEPSC frequency and SFLLRN-NH2significantly increases mEPSC frequency. These data show that astrocytes act within a tripartite synapse in the NST, controlling the excitability of both postsynaptic NST neurons and presynaptic vagal afferent terminals.

Astrocytes have classically been associated with maintenance of neurons. However, since the late 1990s, there has been a dramatic shift in the recognition of the role of astrocytes in central nervous system (CNS) function from passive supporter to active participant (Araque et al. 1999, Bushong et al. 2002, Halassa et al. 2007, Halassa and Haydon 2010, Perea, Navarrete, and Araque 2009, Vance, Rogers, and Hermann 2015). The degree to which astrocytes are involved in regulating central nervous system-wide synaptic function is controversial (Agulhon, Fiacco, and McCarthy 2010, Smith 2010). However, the hindbrain astrocyte has emerged as a powerful component in homeostatic regulation (Agulhon et al. 2013, Funk 2010, Gourine and Kasparov 2011, Gourine et al. 2010, Hermann et al. 2009, Lin et al. 2013, McDougal, Hermann, and Rogers 2013, Vance, Rogers, and Hermann 2015). There are several reports of astrocyte involvement in the regulation of hindbrain synaptic activity (Accorsi-Mendonca, Bonagamba, and Machado 2012, Vance, Rogers, and Hermann 2015), neural inputs regulating astrocyte function (McDougal, Hermann, and Rogers 2011, Porter and McCarthy 1996), and astrocyte involvement as detectors of physiological parameters critical to the maintenance of homeostasis (Funk 2010, Gourine and Kasparov 2011, Accorsi-Mendonca, Bonagamba, and Machado 2012). This chapter reviews recent data that support a special function of astrocytes in the detection of hypoglycemic emergencies and initiation of the rapid, life-saving homeostatic adjustments to hypoglycemia together referred to as “counterregulation.”

Artemisia extracts have been used as remedies for a variety of maladies related to metabolic and gastrointestinal control. Because the vagal afferent-nucleus of the solitary tract (NST) synapse regulates the same homeostatic functions affected by Artemisia, it is possible that these extracts may have activity at the synaptic level in the NST. Therefore, we evaluated how extracts of three common medicinal Artemisia species, Artemisia santolinifolia (SANT), Artemisia scoparia (SCO), and Artemisia dracunculus L (PMI-5011), modulate the excitability of the glutamatergic vagal afferent-NST synapse. Our in vitro live cell calcium imaging data from prelabeled vagal afferent terminals show that SANT extract is a positive modulator of vagal afferent calcium levels, as the extract significantly increased the calcium signal relative to the time control. Neither SCO nor PMI-5011 extract altered the vagal calcium signals compared to the time control. Furthermore, whole cell voltage-clamp recordings from NST neurons corroborated the vagal terminal calcium data in that SANT extract also significantly increased miniature excitatory postsynaptic current (mEPSC) frequency in NST neurons. These data suggest that SANT extract could be a pharmacologically significant mediator of glutamatergic neurotransmission within the CNS.

Fasting and hypoglycemia elicit powerful gastrointestinal contractions. Whereas the relationship between utilizable nutrient and gastric motility is well recognized, the explanation of this phenomenon has remained incomplete. A relatively recent controversial report suggested that astrocytes in the dorsal hindbrain may be the principal detectors of glucoprivic stimuli. Our own studies also show that a subset of astrocytes in the solitary nucleus (NST) is activated by low glucose. It is very likely that information about glucopenia may directly impact gastric control because the hindbrain is also the location of the vago-vagal reflex circuitry regulating gastric motility. Our in vivo single unit neurophysiological recordings in intact rats show fourth ventricular application of 2-deoxyglucose (2-DG) inhibits NST neurons and activates dorsal motor nucleus (DMN) neurons involved in the gastric accommodation reflex. Additionally, as shown in earlier studies, either systemic insulin or central 2-DG causes an increase in gastric motility. These effects on motility were blocked by fourth ventricle pretreatment with the astrocyte inactivator fluorocitrate. Fluorocitrate administered alone has no effect on gastric-NST or -DMN neuron responsiveness, or on gastric motility. These results suggest that glucoprivation-induced increases in gastric motility are dependent on intact hindbrain astrocytes.

Objective St. John’s Wort (SJW) extract, which is commonly used to treat depression, inhibits the reuptake of several neurotransmitters, including glutamate, serotonin, norepinephrine, and dopamine. Glutamatergic visceral vagal afferents synapse upon neurons of the solitary tract (NST); thus, the aim of this study was to evaluate whether SJW extract modulates glutamatergic neurotransmission within the NST. Methods We used live cell calcium imaging to evaluate whether SJW and its isolated components hypericin and hyperforin increase the excitability of prelabeled vagal afferent terminals synapsing upon the NST. We used voltage-clamp recordings of spontaneous miniature excitatory postsynaptic currents (mEPSCs) to evaluate whether SJW alters glutamate release from vagal afferents onto NST neurons. Results Our imaging data show that SJW (50 μg/mL) increased the intracellular calcium levels of stimulated vagal afferent terminals compared with the bath control. This increase in presynaptic vagal afferent calcium by the extract coincides with an increase in neurotransmitter release within the nucleus of the solitary tract, as the frequency of mEPSCs is significantly higher in the presence of the extract compared with the control. Finally, our imaging data show that hyperforin, a known component of SJW extract, also significantly increases terminal calcium levels. Conclusion These data suggest that SJW extract can significantly increase the probability of glutamate release from vagal afferents onto the NST by increasing presynaptic calcium. The in vitro vagal afferent synapse with NST neurons is an ideal model system to examine the mechanism of action of botanical agents on glutamatergic neurotransmission.

Radical cystectomy (RC) and pelvic lymph node dissection (LND) are standard treatments for muscle-invasive urothelial carcinoma of the bladder. Lymph node staging is a prerequisite for clinical decision-making regarding adjuvant chemotherapy and follow-up regimens. Recently, the clinical and pathological nodal staging scores (cNSS and pNSS) were developed. Prior to RC, cNSS determines the minimum number of lymph nodes required to be dissected; pNSS quantifies the accuracy of negative nodal staging based on pT stage and dissected LNs. cNSS and pNSS have not been externally validated, and their relevance for prediction of cancer-specific mortality (CSM) has not been assessed. In this retrospective study of 2,483 RC patients from eight German centers, we externally validated cNSS and pNSS and determined their prediction of CSM. All patients underwent RC and LND. Median follow-up was 44 months. cNSS and pNSS sensitivities were evaluated using the original beta-binominal models. Adjusted proportional hazards models were calculated for pN0 patients to assess the predictive value of cNSS and pNSS for CSM. cNSS and pNSS both pass external validation. Adjusted for other clinical parameters, cNSS can predict outcome after RC. pNSS has no independent impact on prediction of CSM. The retrospective design is the major limitation of the study. In the present external validation, we confirm the validity of both cNSS and pNSS. cNSS is an independent predictor of CSM, thus rendering it useful as a tool for planning the extent of LND.