A neural circuit mechanism for mechanosensory feedback control of ingestion.

Mechanosensory feedback from the digestive tract to the brain is critical for limiting excessive food and water intake, but the underlying gut-brain communication pathways and mechanisms remain poorly understood1-12. Here we show that, in mice, neurons in the parabrachial nucleus that express the prodynorphin gene (hereafter, PBPdyn neurons) monitor the intake of both fluids and solids, using mechanosensory signals that arise from the upper digestive tract. Most individual PBPdyn neurons are activated by ingestion as well as the stimulation of the mouth and stomach, which indicates the representation of integrated sensory signals across distinct parts of the digestive tract. PBPdyn neurons are anatomically connected to the digestive periphery via cranial and spinal pathways; we show that, among these pathways, the vagus nerve conveys stomach-distension signals to PBPdyn neurons. Upon receipt of these signals, these neurons produce aversive and sustained appetite-suppressing signals, which discourages the initiation of feeding and drinking (fully recapitulating the symptoms of gastric distension) in part via signalling to the paraventricular hypothalamus. By contrast, inhibiting the same population of PBPdyn neurons induces overconsumption only if a drive for ingestion exists, which confirms that these neurons mediate negative feedback signalling. Our findings reveal a neural mechanism that underlies the mechanosensory monitoring of ingestion and negative feedback control of intake behaviours upon distension of the digestive tract.

Peroneus Longus Tendon Autograft May Present a Viable Alternative for Anterior Cruciate Ligament Reconstruction: A Systematic Review.

PURPOSE: To examine the available literature to better understand the objective and patient-reported outcomes using peroneus longus tendon (PLT) autograft compared with more commonly used autografts, such as the quadrupled hamstring tendons (HT), in patients undergoing primary for anterior cruciate ligament reconstruction (ACLR). METHODS: A comprehensive search of published literature in PubMed, Web of Science, Cochrane Library, Ovid, and EMBASE databases was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria included patients undergoing ACLR with PLT autograft, inclusion of patient-recorded outcome measures, and availability in English language. Publications that included only biomechanical analysis or ACLR with use of allograft or combination grafts were excluded. RESULTS: A total of 16 studies (Level of Evidence range: I-IV) met inclusion criteria, with follow-up ranging from 3 months to 5 years. In the available case series, patient-reported outcomes ranged from Lysholm = 80.7 to 95.1, International Knee Documentation Committee 78.1 to 95.7. In prospective cohorts and randomized controlled trials, PLT performance was comparable with HT autografts (PLT/HT: Lysholm = 88.3-95.1/86.5-94.9, International Knee Documentation Committee = 78.2-92.5/87.4-93.4). The majority of PLT grafts diameters were equal or greater than HT counterparts with a mean of >8 mm (PLT/HT: 7.0-9.0 mm/7.65-8.5 mm). There was minimal donor-site morbidity associated with PLT harvest. CONCLUSIONS: Although limitations exist within the available literature, existing evidence suggests that PLT autograft routinely produces adequately sized grafts with comparable early outcomes to HT autograft and low risk of donor-site morbidity. However, the PLT autograft is yet to demonstrate superiority to any of the more-traditional autograft selections. LEVEL OF EVIDENCE: Level IV, systematic review of Level I-IV studies.

Use of a dual-purpose implant scan body to obtain both digital and analog records for complete arch fixed implant restorations.

A technique is described for capturing relative dental implant positions for an implant-supported fixed prosthesis in a completely edentulous arch with a novel implant indexing apparatus that also functions as a scannable verification device. A series of intraoral scans are made to record the contours and occlusal records of the existing prosthetics and soft tissue. The individual scans are aligned by using a dental software program to design either an interim or definitive prosthesis. The technique reduces the time needed to gather the records dental laboratory technicians require to fabricate a complete arch implant-supported prosthesis.

Disparities in the prevalence of cigarette smoking among bisexual people: a systematic review, meta-analysis and meta-regression.

OBJECTIVE: To review the bisexual-specific prevalence and likelihood of cigarette smoking relative to lesbian/gay and heterosexual individuals. DATA SOURCES: We searched MEDLINE, PsycInfo, CINAHL, Scopus and LGBT Life databases (from 1995 to September 2019) for studies reporting cigarette smoking among bisexuals versus their comparators. STUDY SELECTION: Observational, quantitative, peer-reviewed studies providing estimates for lifetime, past 30 days or current cigarette smoking among bisexuals and any of the two comparators were selected. DATA EXTRACTION: Data on sexual orientation groups, cigarette smoking, sample type and mechanism, data collection mode, country and median year, as well as gender and age groups were extracted. DATA SYNTHESIS: Random-effects meta-analysis was used to estimate the pooled OR (95% CIs) of cigarette smoking. Meta-regression was used to examine the difference in the prevalence of cigarette smoking by study and sample characteristics. Of 4663 unduplicated records, 47 unique studies were included (14, 23 and 22 studies on lifetime, past 30 days and current cigarette smoking, respectively). Compared with lesbians/gays and heterosexuals, bisexuals were 1.25 (1.15 to 1.37) and 2.18 (1.84 to 2.59) times more likely to report lifetime smoking, 1.17 (1.08 to 1.27) and 2.49 (2.20 to 2.83) times more likely to report past 30 days smoking and 1.19 (1.00 to 1.43) and 2.26 (1.97 to 2.59) times more likely to report current smoking. Gender was a significant covariate in the meta-regression models. CONCLUSIONS: Cigarette smoking was more prevalent among bisexuals than lesbians/gays and heterosexuals, with the estimates showing a greater magnitude among bisexual women relative to all other sexual orientation/gender subgroups.

Large-Scale 3D Optical Mapping and Quantitative Analysis of Nanoparticle Distribution in Tumor Vascular Microenvironment.

Nanoparticles (NPs) are a promising carrier for cancer therapeutics. Systemically administered NPs are transported to tumor tissues via the bloodstream, extravasated from microvessels, and delivered to cancer cells. The distribution of NPs in the tumor vascular microenvironment critically determines the therapeutic efficacy of NP-delivered drugs, but its precise assessment in 3D across a large volume remains challenging. Here, an analytical platform-termed OMNIA (for Optical Mapping of Nanoparticles and Image Analysis)-integrating tissue clearing, high-resolution optical imaging, and semiautomated image analysis is presented, which enables accurate, unbiased, and quantitative analysis of the distribution of NPs in relation to the vasculature across a large 3D volume. Application of OMNIA to tumor tissues revealed higher accumulation and more efficient extravasation of NPs in the tumor periphery than the core. Time-course analysis demonstrated that the accumulation of NPs in tumor peaked at 24 h after injection, but the relative distribution of NPs from the vasculature remained remarkably stable over time. Comparisons between 45- and 200-nm-sized NPs showed a lower accumulation of smaller NPs in tumors relative to the liver, yet better vessel permeation. Together, our results demonstrate that OMNIA facilitates precise and reliable evaluation of NP biodistribution, and mechanistic investigations on NP delivery to tumor tissues.

Statistical Fragility Analysis of Open Reduction Internal Fixation vs Primary Arthrodesis to Treat Lisfranc Injuries: A Systematic Review.

BACKGROUND: There is a lack of consensus in the use of open reduction internal fixation (ORIF) vs primary arthrodesis (PA) in the management of Lisfranc injuries. Statistical fragility represents the number of events needed to flip statistical significance and provides context to interpret P values of outcomes from conflicting studies. The current study evaluates the statistical fragility of existing research with an outcome-specific approach to provide statistical clarity to the ORIF vs PA discussion. We hypothesized that statistical fragility analysis would offer clinically relevant insight when interpreting conflicting outcomes regarding ORIF vs PA management of Lisfranc injuries. METHODS: All comparative studies, RCTs, and case-series investigating ORIF vs PA management of Lisfranc injuries published through October 5, 2023, were identified. Descriptive characteristics, dichotomous outcomes, and continuous outcomes were extracted. Fragility index and continuous fragility index were calculated by the number of event reversals needed to alter significance. Outcomes were categorized by clinical relevance, and median FI and CFI were reported. RESULTS: A total of 244 studies were screened. Ten studies and 67 outcomes (44 dichotomous, 23 continuous) were included in the fragility analysis. Of the 10 studies, 4 studies claimed PA to correlate with superior outcomes compared to ORIF with regard to functional scores and return to function outcomes. Of these 4 studies, 3 were statistically robust. Six studies claimed PA and ORIF to have no differences in outcomes, in which only 2 studies were statistically robust. CONCLUSION: The overall research regarding ORIF vs PA is relatively robust compared with other orthopaedic areas of controversy. Although the full statistical context of each article must be considered, studies supporting PA superiority with regard to functional scores and return to function metrics were found to be statistically robust. Outcome-specific analysis revealed moderate fragility in several clinically relevant outcomes such as functional score, return to function, and wound complications.

HSP27 Inhibitory Activity against Caspase-3 Cleavage and Activation by Caspase-9 Is Enhanced by Chaperone O-GlcNAc Modification in Vitro.

One of the O-GlcNAc modifications is the protection of cells against a variety of stressors that result in cell death. Previous experiments have focused on the overall ability of O-GlcNAc to prevent protein aggregation under stress as well as its ability to affect stress-response signaling pathways. Less attention has been paid to the potential role for O-GlcNAc in the direct inhibition of a major cell-death pathway, apoptosis. Apoptosis involves the sequential activation of caspase proteases, including the transfer of cell-stress information from initiator caspase-9 to effector caspase-3. Cells have multiple mechanisms to slow the apoptotic cascade, including heat shock protein HSP27, which can directly inhibit the activation of caspase-3 by caspase-9. We have previously shown that O-GlcNAc modification increases the chaperone activity of HSP27 against amyloid aggregation, raising the question as to whether this modification may play important roles in other facets of HSP27 biology. Here, we use protein chemistry to generate different versions of O-GlcNAc modified HSP27 and demonstrate that the modification enhances this antiapoptotic function of the chaperone, at least in an in vitro context. These results provide additional molecular insight into how O-GlcNAc functions as a mediator of cellular stress with important implications for human diseases like cancer and neurodegeneration.

O-GlcNAc Modification Alters the Chaperone Activity of HSP27 Charcot-Marie-Tooth Type 2 (CMT2) Variants in a Mutation-Selective Fashion.

Increased O-GlcNAc is a common feature of cellular stress, and the upregulation of this dynamic modification is associated with improved survival under these conditions. Likewise, the heat shock proteins are also increased under stress and prevent protein misfolding and aggregation. We previously linked these two phenomena by demonstrating that O-GlcNAc directly increases the chaperone of certain small heat shock proteins, including HSP27. Here, we examine this linkage further by exploring the potential function of O-GlcNAc on mutants of HSP27 that cause a heritable neuropathy called Charcot-Marie-Tooth type 2 (CMT2) disease. Using synthetic protein chemistry, we prepared five of these mutants bearing an O-GlcNAc at the major site of modification. Upon subsequent biochemical analysis of these proteins, we found that O-GlcNAc has different effects, depending on the location of the individual mutants. We believe that this has important implications for O-GlcNAc and other PTMs in the context of polymorphisms or diseases with high levels of protein mutation.

Brain circuits for promoting homeostatic and non-homeostatic appetites.

As the principal means of acquiring nutrients, feeding behavior is indispensable to the survival and well-being of animals. In response to energy or nutrient deficits, animals seek and consume food to maintain energy homeostasis. On the other hand, even when animals are calorically replete, non-homeostatic factors, such as the sight, smell, and taste of palatable food, or environmental cues that predict food, can stimulate feeding behavior. These homeostatic and non-homeostatic factors have traditionally been investigated separately, but a growing body of literature highlights that these factors work synergistically to promote feeding behavior. Furthermore, recent breakthroughs in cell type-specific and circuit-specific labeling, recording, and manipulation techniques have markedly accelerated the discovery of well-defined neural populations underlying homeostatic and non-homeostatic appetite control, as well as overlapping circuits that contribute to both types of appetite. This review aims to provide an update on our understanding of the neural circuit mechanisms for promoting homeostatic and non-homeostatic appetites, focusing on the function of recently identified, genetically defined cell types.

A forebrain neural substrate for behavioral thermoregulation.

Thermoregulatory behavior is a basic motivated behavior for body temperature homeostasis. Despite its fundamental importance, a forebrain region or defined neural population required for this process has yet to be established. Here, we show that Vgat-expressing neurons in the lateral hypothalamus (LHVgat neurons) are required for diverse thermoregulatory behaviors. The population activity of LHVgat neurons is increased during thermoregulatory behavior and bidirectionally encodes thermal punishment and reward (P&R). Although this population also regulates feeding and caloric reward, inhibition of parabrachial inputs selectively impaired thermoregulatory behaviors and encoding of thermal stimulus by LHVgat neurons. Furthermore, two-photon calcium imaging revealed a subpopulation of LHVgat neurons bidirectionally encoding thermal P&R, which is engaged during thermoregulatory behavior, but is largely distinct from caloric reward-encoding LHVgat neurons. Our data establish LHVgat neurons as a required neural substrate for behavioral thermoregulation and point to the key role of the thermal P&R-encoding LHVgat subpopulation in thermoregulatory behavior.

Expansion Microscopy with a Thermally Adjustable Expansion Factor Using Thermoresponsive Biospecimen-Hydrogel Hybrids.

Expansion microscopy (ExM) is a technique in which swellable hydrogel-embedded biological samples are physically expanded to effectively increase imaging resolution. Here, we develop thermoresponsive reversible ExM (T-RevExM), in which the expansion factor can be thermally adjusted in a reversible manner. In this method, samples are embedded in thermoresponsive hydrogels and partially digested to allow for reversible swelling of the sample-gel hybrid in a temperature-dependent manner. We first synthesized hydrogels exhibiting lower critical solution temperature (LCST)- and upper critical solution temperature (UCST)-phase transition properties with N-alkyl acrylamide or sulfobetaine monomers, respectively. We then formed covalent hybrids between the LCST or UCST hydrogel and biomolecules across the cultured cells and tissues. The resulting hybrid could be reversibly swelled or deswelled in a temperature-dependent manner, with LCST- and UCST-based hybrids negatively and positively responding to the increase in temperature (termed thermonegative RevExM and thermopositive RevExM, respectively). We further showed reliable imaging of both unexpanded and expanded cells and tissues and demonstrated minimal distortions from the original sample using conventional confocal microscopy. Thus, T-RevExM enables easy adjustment of the size of biological samples and therefore the effective magnification and resolution of the sample, simply by changing the sample temperature.

Hidradenitis suppurativa for the nondermatology clinician.

Hidradenitis suppurativa (HS) is a chronic, recurrent inflammatory skin condition resulting in the formation of nodules, sinus tracts, and abscesses typically in intertriginous regions. HS management is often difficult and involves a multimodal approach, evaluating the benefit of both medical and surgical treatment options, along with treating associated pain and medical comorbidities that present concomitantly with the disease. In this article, we synthesize for the nondermatology clinician the evidence for various HS treatments, along with the diagnostic and therapeutic guidelines for HS published by the British Association of Dermatologists, US and Canadian HS Foundations, HS ALLIANCE, Canadian Dermatology Association, and Brazilian Society of Dermatology. Management of HS requires an individualized, patient-centered approach due to the lack of rigorous evidence for many interventions.