Anastomosis technique and leakage rates in minimally invasive surgery for right-sided colon cancer. A retrospective national cohort study.

PURPOSE: The aim of this study was to describe the different techniques currently used in Denmark to construct right-sided ileocolic anastomoses in minimally invasive surgery, and investigate, compare and analyse the anastomotic configurations and their anastomotic leakage (AL) rates. METHODS: This was a retrospective register-based, study design using prospectively collected data from the Danish Colorectal Cancer Group (DCCG) database. All patients aged 18 years or older with a malignant colorectal tumour in Denmark in the period of 1 February 2015 until 31 December 2019, and who had an elective, curative, minimally invasive right hemicolectomy (MIRH) with ileocolic anastomosis, were included. RESULTS: Three thousand three hundred ninety-eight patients were included. The most commonly used anastomotic approach was the extracorporeal (EC) hand-sewn anastomosis (HA) with end-to-end configuration (59%) and the second most used was the EC stapled anastomosis (SA) side-to-side configuration (20%). The latter had a higher AL rate compared with the hand-sewn technique (3.8% vs. 1.3%), and had significantly higher odds ratio (OR) (OR: 2.85, 95% CI: 1.56-4.92, p < 0.0001) for AL in the adjusted regression model. The least used technique was the end-to-side HA which also had a significantly higher OR (OR: 3.05, 95% CI: 1.30-7.15, p = 0.010) compared with the end-to-end HA. Smoking was an independent factor associated with higher OR for AL. CONCLUSION: The ileocolic end-to-end HA was the most commonly used technique and had the lowest AL rate in MIRH for colon cancer. The EC SA technique and tobacco smoking were independent risk factors for leakage of the ileocolic anastomosis.

Prefrontal neuronal assemblies temporally control fear behaviour.

Precise spike timing through the coordination and synchronization of neuronal assemblies is an efficient and flexible coding mechanism for sensory and cognitive processing. In cortical and subcortical areas, the formation of cell assemblies critically depends on neuronal oscillations, which can precisely control the timing of spiking activity. Whereas this form of coding has been described for sensory processing and spatial learning, its role in encoding emotional behaviour remains unknown. Fear behaviour relies on the activation of distributed structures, among which the dorsal medial prefrontal cortex (dmPFC) is known to be critical for fear memory expression. In the dmPFC, the phasic activation of neurons to threat-predicting cues, a spike-rate coding mechanism, correlates with conditioned fear responses and supports the discrimination between aversive and neutral stimuli. However, this mechanism does not account for freezing observed outside stimuli presentations, and the contribution of a general spike-time coding mechanism for freezing in the dmPFC remains to be established. Here we use a combination of single-unit and local field potential recordings along with optogenetic manipulations to show that, in the dmPFC, expression of conditioned fear is causally related to the organization of neurons into functional assemblies. During fear behaviour, the development of 4 Hz oscillations coincides with the activation of assemblies nested in the ascending phase of the oscillation. The selective optogenetic inhibition of dmPFC neurons during the ascending or descending phases of this oscillation blocks and promotes conditioned fear responses, respectively. These results identify a novel phase-specific coding mechanism, which dynamically regulates the development of dmPFC assemblies to control the precise timing of fear responses.

Prefrontal parvalbumin interneurons shape neuronal activity to drive fear expression.

Synchronization of spiking activity in neuronal networks is a fundamental process that enables the precise transmission of information to drive behavioural responses. In cortical areas, synchronization of principal-neuron spiking activity is an effective mechanism for information coding that is regulated by GABA (γ-aminobutyric acid)-ergic interneurons through the generation of neuronal oscillations. Although neuronal synchrony has been demonstrated to be crucial for sensory, motor and cognitive processing, it has not been investigated at the level of defined circuits involved in the control of emotional behaviour. Converging evidence indicates that fear behaviour is regulated by the dorsomedial prefrontal cortex (dmPFC). This control over fear behaviour relies on the activation of specific prefrontal projections to the basolateral complex of the amygdala (BLA), a structure that encodes associative fear memories. However, it remains to be established how the precise temporal control of fear behaviour is achieved at the level of prefrontal circuits. Here we use single-unit recordings and optogenetic manipulations in behaving mice to show that fear expression is causally related to the phasic inhibition of prefrontal parvalbumin interneurons (PVINs). Inhibition of PVIN activity disinhibits prefrontal projection neurons and synchronizes their firing by resetting local theta oscillations, leading to fear expression. Our results identify two complementary neuronal mechanisms mediated by PVINs that precisely coordinate and enhance the neuronal activity of prefrontal projection neurons to drive fear expression.

Impact of an in-consult patient decision aid on treatment choices and outcomes of management for patients with an endoscopically resected malignant colorectal polyp: a study protocol for a non-randomised clinical phase II study.

INTRODUCTION: Management of an endoscopically resected malignant colorectal polyps can be challenging due to the risk of residual tumour and lymphatic spread. International studies have shown, that of those choosing surgical management instead of surveillance strategy, there are between 54% and 82% of bowel resections without evidence of residual tumour or lymphatic spread. As surgical management entails risks of complications and surveillance strategy entails risks of residual tumour or recurrence, a clinical dilemma arises when choosing a management strategy. Shared decision-making is a concept that can be used in preference-sensitive decision-making to facilitate patient involvement and empowerment to facilitate active patient participation in the decision-making process. METHODS AND ANALYSIS: This study protocol describes our clinical multi-institutional, non-randomised, interventional phase II study at Danish surgical departments planned to commence in the second quarter of 2024. The aim of this study is to examine whether shared decision-making and using a patient decision aid in consultations affect patients' choice of management, comparing with retrospective data. The secondary aim is to investigate patients' experiences, perceived involvement, satisfaction, decision conflict and other outcomes using questionnaire feedback directly from the patients. ETHICS AND DISSEMINATION: There are no conflicts of interest for principal or local investigators in any of the study sites. All results will be published at Danish and international meetings, and in English language scientific peer-reviewed journals. Our study underwent evaluation by the Regional Committees on Health Research Ethics for Southern Denmark (file number 20232000-47), concluding that formal approval was not required for this kind of research. TRIAL REGISTRATION NUMBER: NCT05776381.

Engineering 3D micro-compartments for highly efficient and scale-independent expansion of human pluripotent stem cells in bioreactors.

Human pluripotent stem cells (hPSCs) have emerged as the most promising cellular source for cell therapies. To overcome the scale-up limitations of classical 2D culture systems, suspension cultures have been developed to meet the need for large-scale culture in regenerative medicine. Despite constant improvements, current protocols that use microcarriers or generate cell aggregates only achieve moderate amplification performance. Here, guided by reports showing that hPSCs can self-organize in vitro into cysts reminiscent of the epiblast stage in embryo development, we developed a physio-mimetic approach for hPSC culture. We engineered stem cell niche microenvironments inside microfluidics-assisted core-shell microcapsules. We demonstrate that lumenized three-dimensional colonies significantly improve viability and expansion rates while maintaining pluripotency compared to standard hPSC culture platforms such as 2D cultures, microcarriers, and aggregates. By further tuning capsule size and culture conditions, we scale up this method to industrial-scale stirred tank bioreactors and achieve an unprecedented hPSC amplification rate of 277-fold in 6.5 days. In brief, our findings indicate that our 3D culture system offers a suitable strategy both for basic stem cell biology experiments and for clinical applications.

[Metastasis from a malignant melanoma presenting as a gall bladder polyp].

Gall bladder polyps larger than 10 mm hold an increased risk of malignancy. In this case report, a metastasis from a superficial spreading malignant melanoma level IV presented as a large gall bladder polyp in a 52-year-old woman. The melanoma had been surgically resected eight years earlier. The most frequent distant metastatic sites of malignant melanoma are soft tissue, lung, liver, skin and brain, but metastasis to the gallbladder is rare. It is important to refer patients with large gall bladder polyps to centres with expertise in liver surgery.

[Palliative treatment of malignant gastric outlet obstruction].

In gastric outlet obstruction (GOO) the passage from the stomach to the intestine is obstructed. The condition is referred to as malignant GOO if cancer is the reason. Self-expanding metal stents (SEMS) and gastrojejunostomy (GEA) are the therapeutic options for palliation, with SEMS often being recommended as first choice. However, no major difference in terms of clinical success has been shown between SEMS and GEA in comparative studies. Thus, the choice between SEMS and GEA should be made on an individual basis. If SEMS is chosen, covered and uncovered stents offer equal success rates.

4-Hz oscillations synchronize prefrontal-amygdala circuits during fear behavior.

Fear expression relies on the coordinated activity of prefrontal and amygdala circuits, yet the mechanisms allowing long-range network synchronization during fear remain unknown. Using a combination of extracellular recordings, pharmacological and optogenetic manipulations, we found that freezing, a behavioral expression of fear, temporally coincided with the development of sustained, internally generated 4-Hz oscillations in prefrontal-amygdala circuits. 4-Hz oscillations predict freezing onset and offset and synchronize prefrontal-amygdala circuits. Optogenetic induction of prefrontal 4-Hz oscillations coordinates prefrontal-amygdala activity and elicits fear behavior. These results unravel a sustained oscillatory mechanism mediating prefrontal-amygdala coupling during fear behavior.

Frequency of cocaine self-administration influences drug seeking in the rat: optogenetic evidence for a role of the prelimbic cortex.

High-frequency intake and high drug-induced seeking are associated with cocaine addiction in both human and animals. However, their relationships and neurobiological underpinnings remain hypothetical. The medial prefrontal cortex (mPFC), basolateral amygdala (BLA), and nucleus accumbens (NAc) have been shown to have a role in cocaine seeking. However, their involvement in regulating high-frequency intake and high cocaine-induced seeking is unclear. We manipulated frequency of cocaine self-administration and investigated whether it influenced cocaine seeking. The contribution of the aforementioned structures was evaluated using changes in expression of the immediate early gene c-Fos and targeted optogenetic manipulations. Rats that self-administered at High frequency (short inter-infusion intervals allowed by short time-out) showed higher cocaine-induced seeking than low frequency rats (long inter-infusions intervals imposed by long time-out), as measured with cocaine-induced reinstatement. c-Fos was enhanced in High frequency rats in the prelimbic (PL) and infralimbic (IL) areas of the mPFC, the BLA, and the NAc core and shell. Correlational analysis of c-Fos revealed that the PL was a critical node strongly correlated with both the IL and NAc core in High frequency rats. Targeted optogenetic inactivation of the PL decreased cocaine-induced reinstatement, but increased cocaine self-administration, in High frequency rats. In contrast, optogenetic activation of the PL had no effect on Low frequency rats. Thus, high-frequency intake promotes a PL-dependent control of cocaine seeking, with the PL exerting a facilitatory or inhibitory effect, depending on operant contingencies. Individual differences in cocaine-induced PL activation might be a source of vulnerability for poorly controlled cocaine-induced seeking and/or cocaine intake.