Characterization of a novel and selective cannabinoid CB1 receptor inverse agonist, Imidazole 24b, in rodents

We document in vitro and in vivo effects of a novel, selective cannabinoid CB(1) receptor inverse agonist, Imidazole 24b (5-(4-chlorophenyl)-N-cyclohexyl-4-(2,4-dichlorophenyl)-1-methyl-imidazole-2-carboxamide). The in vitro binding affinity of Imidazole 24b for recombinant human and rat CB(1) receptor is 4 and 10 nM, respectively. Imidazole 24b binds to human cannabinoid CB(2) receptor with an affinity of 297 nM; in vitro, it is a receptor inverse agonist at both cannabinoid CB(1) and CB(2) receptors as it causes a further increase of forskolin-induced cAMP increase. Oral administration of Imidazole 24b blocked CP-55940-induced hypothermia, demonstrating cannabinoid CB(1) receptor antagonist efficacy in vivo. Using ex vivo autoradiography, Imidazole 24b resulted in dose-dependent increases in brain cannabinoid CB(1) receptor occupancy (RO) at 2h post-dosing in rats, indicating that approximately 50% receptor occupancy is sufficient for attenuation of receptor agonist-induced hypothermia. Imidazole 24b administered to C57Bl/6 mice and to dietary-induced obese (DIO) Sprague-Dawley rats attenuated overnight food intake with a minimal effective dose of 10 mg/kg, p.o. Administration had no effect in cannabinoid CB(1) receptor-deficient mice. DIO rats were dosed orally with vehicle, Imidazole 24b (1, 3 or 10 mg/kg), or dexfenfluramine (3 mg/kg) for 2 weeks. At 3 mg/kg, Imidazole 24b reduced cumulative food intake, leading to a non-significant decrease in weight gain. Imidazole 24b at 10 mg/kg and dexfenfluramine treatment inhibited food intake and attenuated weight gain. These findings suggest that selective cannabinoid CB(1) receptor inverse agonists such as Imidazole 24b have potential for the treatment of obesity.     

A resident Golgi protein is excluded from peri-Golgi vesicles in NRK cells

To understand the structure and the function of the Golgi apparatus, it is essential to establish how resident Golgi enzymes are localized in only a few Golgi cisternae. In particular it is crucial to establish whether Golgi enzymes are retained specifically in cisternae, or if they are continuously transported from cisterna to cisterna. Here we report that a resident Golgi enzyme is largely excluded from peri-Golgi transport vesicles in normal rat kidney cells, a cell type in which conflicting results have been reported. Analysis of the lateral distribution of two markers within Golgi cisternae led to the same conclusion: a protein incorporated in vesicles (KDEL receptor) is concentrated at the rims of cisternae where vesicles form, while mannosidase II is not. These results suggest that localization of resident Golgi enzymes is achieved primarily by selective retention within cisternae and exclusion from transport vesicles. These observations cannot easily be reconciled with the vision of rapidly maturing Golgi cisternae as the principal means of intra-Golgi transport.     

Polyoxymethylene/silica/polylactic acid-grafted polyethylene glycol nanocomposites: structure,morphology, and mechanical properties and ozone and UV durability

Polyoxymethylene (POM) is a semicrystalline thermoplastic that displays high tensile strength, thermal stability, and chemical durability. However, its widespread application is limited by its low elongation at break and thermal durability. In the present study, nanosilica (NS) and polylactic acid-grafted polyethylene glycol (PELA) were used as enhancement additives to improve the performance of POM homopolymer. Specifically, the POM/PELA/NS nanocomposites with a fixed NS content and varying PELA contents were prepared by a melt mixing method. The influence of the additives on the processability, and dynamic thermo-mechanical and tensile properties of the nanocomposites was evaluated by comparing the torque, mixing energy at melt state, storage modulus, shear stress, loss modulus, tan δ, tensile strength, elongation at break and thermal degradation of the nanocomposites. The results showed that the combined addition of NS and PELA enhanced the thermal stability, tensile strength, elongation at break and chemical stability of the POM/PELA/NS nanocomposites owing to the good compatibility between PELA and the POM matrix. Furthermore, the morphology, and UV and ozone durability of POM and the nanocomposites were assessed and discussed.

The combined addition of nanosilica (NS) and polylactic acid-grafted polyethylene glycol (PELA) enhanced some properties of polyoxymethylene (POM).     

Regional synapse gain and loss accompany memory formation in larval zebrafish

Defining the structural and functional changes in the nervous system underlying learning and memory represents a major challenge for modern neuroscience. Although changes in neuronal activity following memory formation have been studied [B. F. Grewe et al., Nature 543, 670–675 (2017); M. T. Rogan, U. V. Stäubli, J. E. LeDoux, Nature 390, 604–607 (1997)], the underlying structural changes at the synapse level remain poorly understood. Here, we capture synaptic changes in the midlarval zebrafish brain that occur during associative memory formation by imaging excitatory synapses labeled with recombinant probes using selective plane illumination microscopy. Imaging the same subjects before and after classical conditioning at single-synapse resolution provides an unbiased mapping of synaptic changes accompanying memory formation. In control animals and animals that failed to learn the task, there were no significant changes in the spatial patterns of synapses in the pallium, which contains the equivalent of the mammalian amygdala and is essential for associative learning in teleost fish [M. Portavella, J. P. Vargas, B. Torres, C. Salas, Brain Res. Bull. 57, 397–399 (2002)]. In zebrafish that formed memories, we saw a dramatic increase in the number of synapses in the ventrolateral pallium, which contains neurons active during memory formation and retrieval. Concurrently, synapse loss predominated in the dorsomedial pallium. Surprisingly, we did not observe significant changes in the intensity of synaptic labeling, a proxy for synaptic strength, with memory formation in any region of the pallium. Our results suggest that memory formation due to classical conditioning is associated with reciprocal changes in synapse numbers in the pallium.

It is widely believed that memories are formed as a result of alterations in synaptic connections between axons and dendrites, an idea first proposed by Ramon y Cajal (1–4). Although synapse changes have been extensively studied in brain slices in the context of long-term potentiation (5, 6), less is known about how synapses in a living vertebrate are modified when a memory is formed.Memory formation has been widely studied using classical conditioning (CC), a robust and straightforward form of learning in which an animal is exposed to a neutral stimulus (conditioned stimulus, CS) paired with an appetitive or aversive stimulus (unconditioned stimulus, US) that evokes a specific behavioral response (UR, unconditioned response) (7, 8). As a result of the pairing, animals learn to associate the CS with the US, causing them to respond to the CS with a conditioned response (CR) identical to the UR, signifying memory retrieval (9, 10). Memory retrieval is also evoked by activating a cellular engram, a group of neurons active during memory formation and retrieval (11–18). The central locus of CC in mammals, the amygdala (19), is located in a relatively inaccessible area beneath the cortex (20). Thus, although numerous longitudinal imaging studies have documented experience-dependent changes in the structure of spines of cortical and hippocampal neurons (21, 22), few imaging studies have directly examined synaptic changes that occur in the amygdala during associative memory formation.Instead, synaptic changes that occur in the amygdala during CC (23) have been studied primarily using indirect measures of synaptic strength, such as the ratio of α-amino-3-hydroxy-5-methyl-4-isoxazoleproprionic acid receptor/N-methyl D-aspartate (AMPA/NMDA) currents in excitatory postsynaptic currents (EPSCs). Increases in AMPA/NMDA ratio in amygdalar neurons following auditory fear conditioning (FC), a type of CC (24–27), indicate that associative memory formation coincides with increases in synaptic strength. In addition, imaging experiments in brain regions beyond the amygdala have shown diverse effects following CC. For example, following contextual fear conditioning, engram neurons in the CA1 region of the hippocampus that receive inputs from CA3 engram neurons displayed spines that were larger and more densely packed than nonengram cells (28). Furthermore, experiments in which neuronal morphology was directly observed before and after FC found that neurons in the frontal association (29) and primary motor cortex (30) showed a decrease in the number of spines, whereas neurons in the auditory cortex showed an increase in spine number with memory formation (31).To obtain previously unavailable insight into memory formation within the central locus of associative memory storage, we developed a paradigm combining in vivo labeling and imaging with informatics and analysis tools. We used this paradigm to map synaptic changes that occur over time in the intact brain of a living vertebrate during memory formation. We imaged the pallium of teleost fish, which contains the putative homolog of the mammalian amygdala based on anatomy (32), gene expression (33), and function (34). The pallium is on the surface of the brain (35), and zebrafish larvae are highly transparent, allowing for intact, whole-brain imaging using selective plane illumination microscopy (SPIM) without the need for invasive intervention (36). In addition, while most studies of learning in zebrafish have used adults (37–40), at least one study showed that larval zebrafish can learn to associate a place with a positive valence US (41). These attributes suggest that larval zebrafish may be an ideal model organism for studying synaptic changes during memory formation due to CC. We have engaged this challenge by combining purpose-built experimental tools with data management software that enables transparent analyses of large and heterogeneous datasets. All data were characterized and stored at the time of creation in a customized data management system designed to conform to findability, accessibility, interoperability, and reusability (i.e., FAIR principles) (see Materials and Methods) (42).     

Clinical and genetic features of congenital bile acid synthesis defect with a novel mutation in AKR1D1 gene sequencing: Case reports

Rationale:Congenital bile acid synthesis defect (BASD) is a rare disease caused by mutations in the aldo-keto reductase 1D1 gene, which encodes the primary Δ4-3-oxosteroid 5β-reductase enzyme. Early disease diagnosis is critical for early treatment with bile acid replacement therapy, with an excellent chance for recovery. In contrast, protracted diagnosis and treatment may lead to poor outcomes, including decompensated hepatic cirrhosis, liver transplant, and even death.Patient concerns:Three clinical congenital bile acid synthesis defect cases in the Vietnamese population are herein reported. These pediatric patients presented with symptoms of prolonged postpartum jaundice and abnormal loose stool (mucus, lipids, and white). The clinical examinations showed hepatosplenomegaly. Urinalysis showed a very low fraction of primary bile acids and atypical 3-oxo-Δ4- bile acids in all three patients.Diagnoses:The patients were diagnosed with primary Δ4-3-oxosteroid 5β-reductase deficiency. Next-generation gene sequencing revealed two homozygous mutations in the aldo-keto reductase family 1 member D1 gene. The first is a documented variant, c.797G>A (p.Arg266Gln), and the second is a novel mutation at c.155T>C (p.Ile52Thr).Interventions:Immediately after diagnosis, patients were treated with oral chenodeoxycholate 5 mg/kg/d.Outcomes:The patients’ symptoms, signs, and primary bile acids levels improved significantly.Lessons:Clinicians should consider genetic disorders related to cholestasis for effective and life-saving treatment. A prompt genetic analysis by next-generation gene sequencing enables patients to access bile acid replacement therapy earlier, significantly improving short- and long-term outcomes.     

Characteristics of occult hepatitis B virus infection in the Solomon Islands

Hepatitis?B virus (HBV) infection is highly endemic in the Solomon Islands. However, little is known about the status of occult HBV infection in the Solomon Islands. This study aimed to investigate the prevalence of occult HBV infection and its clinical and virological features in the community of Solomon Islands. Blood samples were collected from a total of 564 asymptomatic individuals aged over 18 years in the Western province. The samples used in the present study consisted of 200 samples from 108 males and 92 females (mean age, 37.4 years; range, 18-71 years) that were randomly selected among the hepatitis?B surface antigen (HBsAg)-negative samples from all the participants enrolled in this study. HBV-DNA was detected by real-time?PCR in 25 (12.5%) of the 200 HBsAg-negative samples. Most of the HBV-DNA-positive individuals were infected with wild-type HBV, and only 3 strains demonstrated specific amino acid substitutions (P121X, T123N, C138S, P142S and D144E) in the α?determinant region. In conclusion, occult HBV infection was documented in 12.5% of individuals that demonstrated serologic evidence of resolved HBV infection in this study. The prevalence of occult infection was also influenced by ethnicity; it was more prevalent in Melanesians than Micronesians. In addition, occult HBV infection demonstrated a weak association with the S-variants.     

Integrated CT-PET imaging of esophageal cancer: unexpected and unusual distribution of distant organ metastases

CT-PET imaging is being increasingly used for the initial staging, assessment of treatment response, and follow-up of patients with esophageal carcinoma, primarily because of its superior detection of distant metastases compared to conventional methods. Our recent experience has shown that metastases from esophageal cancer can occur in unusual locations and have an unexpected presentation. Recognition of the distribution and appearance of esophageal metastases is important for optimal image interpretation in order to avoid confusion with more benign disease. This article reviews the location and appearance of metastases detected by CT-PET imaging in patients with esophageal cancer either at presentation or after preoperative or definitive chemoradiation therapy.     

Emergency Department Return Visits Within a Large Geographic Area

Background

Return visits to the emergency department (RTED) contribute to overcrowding and may be a quality of care indicator. Previous studies focused on factors predicting returns to and from the same center. Little is known about RTEDs across a range of community and specialty hospitals within a large geographic area.

Non‐invasive left ventricular myocardial work indices in healthy adolescents at rest

Global myocardial work (GMW) provides a metric of left ventricular (LV) function and energy consumption. Its non-invasive assessment by echocardiography correlates with invasive measures and normal values have been reported in healthy adults. We aimed to establish normal values in a healthy adolescent population. Fifty-two healthy adolescents (mean age?=?14.5?±?2.0 years, range 11–19 years, 62% male) with normal echocardiograms were included. Brachial cuff blood pressure was obtained immediately following apical imaging in the supine position. Post-processing of echocardiograms for speckle tracking strain measurement and derivation of global myocardial work indices from LV pressure–strain loops was performed. The mean global work index (GWI) was 1802.0?±?264.4 mmHg% with mean global work efficiency of 95.5?±?1.1%. The mean global constructive work (GCW) was 2054.5?±?297.3 mmHg%, and the mean global wasted work 83.8?±?28.1 mmHg%. On multivariable analysis, there were significant associations between both GWI and GCW with systolic blood pressure (β coefficient?=?0.57, p?<?0.001; β coefficient?=?0.67, p?<?0.001 respectively) and LV global longitudinal strain (GLS) (β coefficient = ? 0.56, p?<?0.001; β coefficient = ? 0.52, p?<?0.001 respectively). There were no associations with any of the work indices with age, sex, body surface area, heart rate or LV ejection fraction. This study provides echocardiographic reference ranges for non-invasive indices of GMW in normal adolescents.

     

Periodontal disease among the middle-aged Vietnamese population

Information about periodontal disease patterns among the populations of developing countries is limited. These populations may illustrate the natural history of the disease owing to low or virtually no access to dental care, contributing to a more complete understanding of the disease process. The present study aimed to describe the patterns of periodontal loss of attachment (LOA) among representative middle-aged Vietnamese adults. A multi-stage, stratified random sampling technique was employed in two randomly selected provinces. The US NIDR protocol with two sites per tooth for the whole mouth, excluding third molars, was used to assess LOA. A total of 575 subjects aged 35-44 years were interviewed and periodontally examined (response 84.6%). Data were re-weighted to reflect the population of the two provinces. Oral hygiene status was poor with high accumulation of plaque and calculus. The prevalence, extent of sites with pockets (PD), recession (GR) and LOA exceeding various thresholds and the severity of LOA were calculated. Almost all subjects presented with at least one site with LOA > or = 2 mm but the higher levels of the disease were skewed. The extent of sites with GR, PD and LOA > or = 4mm was 1.35, 5.04 and 11.81 per cent respectively. More buccal sites had GR, while more mesial sites had PD and LOA. Severity score of LOA was 2.5 (SD: 0.7). LOA of 4+mm were observed more at maxillary molar buccal sites, followed by mandibular incisor mesial sites. LOA was prevalent among middle-aged Vietnamese adults. The loss of periodontal support was positively skewed and varied between teeth and sites.