Uncoordinated sleep replay across hemispheres in the zebra finch.

Bilaterally organized brain regions are often simultaneously active in both humans1,2,3 and animal models,4,5,6,7,8,9 but the extent to which the temporal progression of internally generated dynamics is coordinated across hemispheres and how this coordination changes with brain state remain poorly understood. To address these issues, we investigated the zebra finch courtship song (duration: 0.5-1.0 s), a highly stereotyped complex behavior10,11 produced by a set of bilaterally organized nuclei.12,13,14 Unilateral lesions to these structures can eliminate or degrade singing,13,15,16,17 indicating that both hemispheres are required for song production.18 Additionally, previous work demonstrated broadly coherent and symmetric bilateral premotor signals during song.9 To precisely track the temporal evolution of activity in each hemisphere, we recorded bilaterally in the song production pathway. We targeted the robust nucleus of the arcopallium (RA) in the zebra finch, where population activity reflects the moment-to-moment progression of the courtship song during awake vocalizations19,20,21,22,23,24 and sleep, where song-related network dynamics reemerge in "replay" events.24,25 We found that activity in the left and right RA is synchronized within a fraction of a millisecond throughout song. In stark contrast, the two hemispheres displayed largely independent replay activity during sleep, despite shared interhemispheric arousal levels. These findings demonstrate that the degree of bilateral coordination in the zebra finch song system is dynamically modulated by behavioral state.

Thalamus drives vocal onsets in the zebra finch courtship song.

While motor cortical circuits contain information related to specific movement parameters1, long-range inputs also have a critical role in action execution2,3. Thalamic projections can shape premotor activity2-6 and have been suggested7 to mediate the selection of short, stereotyped actions comprising more complex behaviours8. However, the mechanisms by which thalamus interacts with motor cortical circuits to execute such movement sequences remain unknown. Here we find that thalamic drive engages a specific subpopulation of premotor neurons within the zebra finch song nucleus HVC (proper name) and that these inputs are critical for the progression between vocal motor elements (that is, 'syllables'). In vivo two-photon imaging of thalamic axons in HVC showed robust song-related activity, and online perturbations of thalamic function caused song to be truncated at syllable boundaries. We used thalamic stimulation to identify a sparse set of thalamically driven neurons within HVC, representing ~15% of the premotor neurons within that network. Unexpectedly, this population of putative thalamorecipient neurons is robustly active immediately preceding syllable onset, leading to the possibility that thalamic input can initiate individual song components through selectively targeting these 'starter cells'. Our findings highlight the motor thalamus as a director of cortical dynamics in the context of an ethologically relevant behavioural sequence.

Carvedilol versus endoscopic band ligation for secondary prophylaxis of variceal bleeding-long-term follow-up of a randomised control trial.

BACKGROUND AND AIMS: Carvedilol reduces rates of variceal bleeding and rebleeding by lowering portal pressure. However, an associated pleiotropic survival benefit has been proposed. We aimed to assess long-term survival in a cohort of patients previously randomised to receive either carvedilol or endoscopic band ligation (EBL) following oesophageal variceal bleeding (OVB). METHODS: The index study randomised 64 cirrhotic patients with OVB between 2006 and 2011 to receive either carvedilol or EBL. Follow-up was undertaken to April 2020 by review of electronic patient records. The primary outcome was survival. Other outcomes including variceal rebleeding and liver decompensation events were compared. RESULTS: 26 out of 33 participants received carvedilol in the follow-up period and 28 out of 31 attended regular EBL sessions. The median number of follow-up days for all patients recruited was 1459 (SE = 281.74). On the intention to treat analysis, there was a trend towards improved survival in the carvedilol group (p = 0.09). On per-protocol analysis, carvedilol use was associated with improved long-term survival (p = 0.005, HR 3.083, 95% CI 1.397-6.809), fewer liver-related deaths (0% vs 22.57%, p = 0.013, OR ∞, 95%CI 1.565-∞) and fewer admissions with decompensated liver disease (12% vs 64.29%, p = 0.0002, OR 13.2, 95% CI 3.026-47.23) compared to the EBL group. There was no statistically significant difference in variceal rebleeding rates. CONCLUSION: Following OVB in cirrhotic patients, carvedilol use is associated with survival benefit, fewer liver-related deaths and fewer hospital admissions with decompensated liver disease. Further studies are needed to validate this finding.

The role of endoscopic ultrasound in the management of intraductal papillary mucinous neoplasms: a systematic update.

The widespread use of cross-sectional imaging has led to an increased frequency of incidentally detected pancreatic cysts. Neoplastic cysts such as mucinous lesions and solid pseudo-papillary neoplasms have malignant potential and therefore the early detection of these lesions presents an opportunity for prevention or early detection and management of pancreatic adenocarcinoma. Serous neoplastic lesions and non-neoplastic pancreatic cysts such as pseudocysts or walled off pancreatic necrosis and are not associated with malignant potential. It is important to identify those mucinous lesions with the highest potential of malignancy in order to direct management either towards surveillance or resection. The preoperative diagnosis of these cysts is a challenge as cross-sectional imaging alone is often inadequate at making the diagnosis. Endoscopic ultrasound (EUS) with or without fine-needle aspiration (FNA) can assess the morphology of cysts including identification of high risk characteristics of cysts as well as allowing aspiration of cyst fluid, which can be analyzed for cytology, mucin, tumor markers, amylase and molecular markers. Intraductal papillary mucinous neoplasms (IPMN) have three main subtypes; main duct IPMNs (MD-IPMN), branch duct IPMNs (BD-IPMN) and mixed type IPMNs which have feature of both the aforementioned. MD-IPMNs have the highest malignant potential and are often easier to identify on cross-sectional imaging due to the involvement of the main pancreatic duct. Current guidelines suggest that these lesions should generally be considered for resection without further evaluation. Several guidelines exist for the investigation and management of BD-IPMNs, which have a lower malignant potential and there has been much interest in more clearly defining the role of EUS and EUS-FNA in this group of patients. In this review article we discuss the role of EUS in the diagnosis, risk stratification and management of these lesions.

A prospective evaluation of the predictive value of faecal calprotectin in quiescent Crohn's disease.

BACKGROUND: Faecal calprotectin (FC) is a non-invasive marker of gastrointestinal inflammation. AIM: To determine whether higher FC levels in individuals with quiescent Crohn's disease are associated with clinical relapse over the ensuing 12 months. METHODS: A single centre prospective study was undertaken in Crohn's disease patients in clinical remission. The receiver operating characteristic (ROC) curve for the primary endpoint of clinical relapse by 12 months, based on FC at baseline, was calculated. Kaplan-Meier curves of time to relapse were based on the resulting optimal FC cutoff for predicting relapse. RESULTS: Of 97 patients recruited, 92 were either followed up for 12 months without relapsing, or reached the primary endpoint within that period. Of these, 10 (11%) relapsed by 12 months. Median FC was lower for non-relapsers, 96 µg/g (IQR 39-237), than for relapsers, 414 µg/g (IQR 259-590), (p=0.005). The area under the ROC curve to predict relapse using FC was 77.4%. An optimal cutoff FC value of 240 µg/g to predict relapse had sensitivity of 80.0% and specificity of 74.4%. Negative predictive value was 96.8% and positive predictive value was 27.6%, FC ≥240 µg/g was associated with likelihood of relapse by 12-months 12.18 (95% CI 2.55-58.2) times higher than lower values (p=0.002). CONCLUSIONS: In this prospective dataset, FC is a useful tool to help identify quiescent Crohn's disease patients at a low risk of relapse over the ensuing 12 months. FC of 240 µg/g was the optimal cutoff in this cohort.

Hemospray application in nonvariceal upper gastrointestinal bleeding: results of the Survey to Evaluate the Application of Hemospray in the Luminal Tract.

BACKGROUND: Hemospray TM (TC-325) is a novel hemostatic agent licensed for use in nonvariceal upper gastrointestinal bleeding (NVUGIB) in Europe. GOALS: We present the operating characteristics and performance of TC-325 in the largest registry to date of patients presenting with NVUGIB in everyday clinical practice. METHODS: Prospective anonymized data of device performance and clinical outcomes were collected from 10 European centers using the multicentre SEAL survey (Survey to Evaluate the Application of Hemospray in the Luminal tract). TC-325 was used as a monotherapy or as second-line therapy in combination with other hemostatic modalities at the endoscopists' discretion. RESULTS: Sixty-three patients (44 men, 19 women), median age 69 (range, 21 to 98) years with NVUGIB requiring endoscopic hemostasis were treated with TC-325. There were 30 patients with bleeding ulcers and 33 with other NVUGIB pathology. Fifty-five (87%) were treated with TC-325 as monotherapy; 47 [85%; 95% confidence interval (CI), 76%-94%] of them achieved primary hemostasis, and rebleeding rate at 7 days was 15% (95% CI, 5%-25%). Primary hemostasis rate for TC-325 in patients with ulcer bleeds was 76% (95% CI, 59%-93%). Eight patients, who otherwise may have required either surgery or interventional radiology, were treated with TC-325 as second-line therapy after failure of other endoscopic treatments, all of whom achieved hemostasis following the adjunct of TC-325. CONCLUSIONS: This multicentre registry identifies potentially useful characteristics of Hemospray (TC-325) when used either as monotherapy or as a rescue therapy in a wide variety of ulcer and nonulcer NVUGIB.

Investigation and management of pancreatic tumours.

Pancreatic cancer is the 10th most commonly diagnosed cancer in the UK and the fifth most common cause of cancer death. It remains one of the most aggressive cancers with over 95% of patients affected dying of their disease. Often presenting at an advanced stage of disease progression, there is currently no simple screening test available. Therefore a high clinical suspicion and prompt appropriate investigation is required from physicians when dealing with patients with symptoms in keeping with pancreatic cancer. The gastroenterology 2010 curriculum states that trainees should learn the presentation and multidisciplinary management of patients with pancreatic tumours. In this article we discuss the typical clinical presentations of common and less common pancreatic tumours followed by the investigation, staging and management required.

Utility of faecal calprotectin analysis in adult inflammatory bowel disease.

The inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis, are chronic relapsing, remitting disorders. Diagnosis, along with assessment of disease activity and prognosis present challenges to managing clinicians. Faecal biomarkers, such as faecal calprotectin, are a non-invasive method which can be used to aid these decisions. Calprotectin is a calcium and zinc binding protein found in the cytosol of human neutrophils and macrophages. It is released extracellularly in times of cell stress or damage and can be detected within faeces and thus can be used as a sensitive marker of intestinal inflammation. Faecal calprotectin has been shown to be useful in the diagnosis of IBD, correlates with mucosal disease activity and can help to predict response to treatment or relapse. With growing evidence supporting its use, over the last decade this faecal biomarker has significantly changed the way IBD is managed.