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Laparoscopic sleeve gastrectomy (SG) is the most commonly performed bariatric procedure. The primary and insidious early post-SG complication is the gastric leak (GL). In literature, there are many studies describing the endoscopic stent placement as treatment of GL and few studies about stent placement performed by interventional radiology under fluoroscopic guide. Our aims were to describe the radiological stent placement technique, to compare endoscopic and radiological stent placement, to illustrate normal diagnostic features and summarise the incidence of complications after stent placement, removal, and their imaging features. This was a single centre retrospective study of 595 patients who underwent SG between 2011 and 2019. Inclusion criteria: patients who developed GL after SG and treated with gastro-oesophageal stent placement by endoscopy or interventional radiology; availability of medical history and imaging studies; follow-up time after stent removal (1 year). The rates of technical success, clinical success and complications after stent placement and removal were collected and compared between the two methods of stent positioning. A total of 17/595 (2.8%) patients developed a radiologically diagnosed GL after SG. The type II-III GLs (15/17) were treated with endoscopic or radiological stent placement. 9/15 (60%/Group A) patients underwent gastro-oesophageal stenting by interventional radiology and 6/15 (40%/Group B) were treated with endoscopic stent placement. The technical and clinical success rate was 100% for both groups. Stent migration occurred in 22% and 27% for Group A and B respectively. Post-extraction stenosis was the main late complication, occurring in 22% in Group A and 0% in Group B. Gastro-esophageal stent placement performed by interventional radiologists is a valid "mini-invasive" treatment for GL. This procedure is not inferior to endoscopic positioning regarding efficacy, periprocedural and postprocedural complication rate. It's necessary to be familiar with radiological findings after stent placement and removal. Computed tomography (CT) scan is the main radiological technique to identify stent placement complications. Upper gastrointestinal (UGI) series are the first radiological procedures used to detect late complications after stent removal., Competing Interests: The authors declare no conflict of interest., (© 2022 The Author(s).)

BACKGROUND Segmental arterial mediolysis (SAM) is an uncommon vascular pathology characterized by arteriopathy, mainly of medium-sized abdominal splanchnic vessels, without an atherosclerotic, inflammatory, infectious, or autoimmune underlying etiology. Segmental arterial mediolysis is clinically heterogeneous and symptoms may be completely nonspecific. The knowledge of radiological features of segmental arterial mediolysis and the exclusion of other pathologies should direct early diagnosis and refer patients for correct treatment. CASE REPORT In the last 2 years, we treated 2 different adult patients (an 89-year-old woman and a 52-year-old man) with spontaneous visceral bleeding, admitted to the Emergency Department due to acute onset of abdominal pain, anemia, and computed tomographic angiography (CTA) evidence of aneurysmatic, and stenotic alterations of splanchnic arteries. Based on clinical, laboratory, and radiological features, segmental arterial mediolysis was suspected. These 2 patients were referred to our Interventional Radiology Department and treated with super-selective transcatheter arterial embolization (TAE), performed by a minimally invasive approach, allowing an immediate clinical improvement with regression of symptoms and avoiding major surgical treatment. CONCLUSIONS In patients with clinical, laboratory, and radiological signs of acute and/or chronic abdominal bleeding and radiological findings suggesting segmental arterial mediolysis, mini-invasive endovascular treatment is a safe, extremely reliable, and secure procedure and appears to be the first-choice treatment when available. Since abdominal bleeding could have fatal consequences in these patients, timely diagnosis and endovascular therapy are essential to treat visceral vascular alterations due to segmental arterial mediolysis.

Introduction: Varicocele is a relatively complex pathology of the scrotum veins', known to be one of the easiest to treat. Modern treatment involves both surgical (open, laparoscopic and microsurgery) and interventional approach (either with coils and/or sclerosant injection). Our aim is to demonstrate the feasibility and the reliability of endovenous laser ablation (EVLA) of the spermatic vein for the treatment of varicocele., Materials and Methods: We consecutively and prospectively treated 11 patients (age range 24-45 years old, mean 31y) with left varicocele, phlebografically classified as Bahren type I and with indication for percutaneous treatment. Clinical success was evaluated by color doppler ultrasound (CDUS) one week, one months and three months after the procedures. We also evaluated the pain feeling for 48 h after the procedure on the basis of the visual analogue score (VAS) obtained through telephonic interview., Results: Technical success was achieved in all cases. In all cases varicocele disappeared at CDUS at 1 and three months with reflux abolition. Two cases of small vein laceration were noted without sequelae, no other complication has been described. All patients reported improvements either regarding symptoms and/or spermiographic parameters., Conclusions: In our experience, EVLA of spermatic vein is a feasible and safe treatment in patients with Bahren type I varicocele. The key advantage of this technique is the adoption of a standardized protocol, which remains one of the main problems in gaining scientific evidence in case of coil or sclerosant embolisation (type and number of coils, amount of sclerosant agent etc).

The dopamine D 3 receptor (D 3 R) is a molecular target for both first-generation and several recently-developed antipsychotic agents. Following stable expression of this mEGFP-tagged receptor, Spatial Intensity Distribution Analysis indicated that a substantial proportion of the receptor was present within dimeric/oligomeric complexes and that increased expression levels of the receptor favored a greater dimer to monomer ratio. Addition of the antipsychotics, spiperone or haloperidol, resulted in re-organization of D 3 R quaternary structure to promote monomerization. This action was dependent on ligand concentration and reversed upon drug washout. By contrast, a number of other antagonists with high affinity at the D 3 R, did not alter the dimer/monomer ratio. Molecular dynamics simulations following docking of each of the ligands into a model of the D 3 R derived from the available atomic level structure, and comparisons to the receptor in the absence of ligand, were undertaken. They showed that, in contrast to the other antagonists, spiperone and haloperidol respectively increased the atomic distance between reference α carbon atoms of transmembrane domains IV and V and I and II, both of which provide key interfaces for D 3 R dimerization. These results offer a molecular explanation for the distinctive ability of spiperone and haloperidol to disrupt D 3 R dimerization.

Systematic halogenation of two native opioid peptides has shown that halogen atoms can modulate peptide-receptor interactions in different manners. First, halogens may produce a steric hindrance that reduces the binding of the peptide to the receptor. Second, chlorine, bromine, or iodine may improve peptide binding if their positive σ-hole forms a halogen bond interaction with negatively charged atoms of the protein. Lastly, the negative electrostatic potential of fluorine can interact with positively charged atoms of the protein to improve peptide binding.

Background: Protein sequence alignments and database search methods use standard scoring matrices calculated from amino acid substitution frequencies in general sets of proteins. These general-purpose matrices are not optimal to align accurately sequences with marked compositional biases, such as hydrophobic transmembrane regions found in membrane proteins. In this work, an amino acid substitution matrix (GPCRtm) is calculated for the membrane spanning segments of the G protein-coupled receptor (GPCR) rhodopsin family; one of the largest transmembrane protein family in humans with great importance in health and disease., Results: The GPCRtm matrix reveals the amino acid compositional bias distinctive of the GPCR rhodopsin family and differs from other standard substitution matrices. These membrane receptors, as expected, are characterized by a high content of hydrophobic residues with regard to globular proteins. On the other hand, the presence of polar and charged residues is higher than in average membrane proteins, displaying high frequencies of replacement within themselves., Conclusions: Analysis of amino acid frequencies and values obtained from the GPCRtm matrix reveals patterns of residue replacements different from other standard substitution matrices. GPCRs prioritize the reactivity properties of the amino acids over their bulkiness in the transmembrane regions. A distinctive role is that charged and polar residues seem to evolve at different rates than other amino acids. This observation is related to the role of the transmembrane bundle in the binding of ligands, that in many cases involve electrostatic and hydrogen bond interactions. This new matrix can be useful in database search and for the construction of more accurate sequence alignments of GPCRs.

The dopamine D3 receptor is a class A, rhodopsin-like G protein-coupled receptor that can form dimers and/or higher order oligomers. However, the molecular basis for production of these complexes is not well defined. Using combinations of molecular modeling, site-directed mutagenesis, and homogenous time-resolved FRET, the interfaces that allow dopamine D3 receptor monomers to interact were defined and used to describe likely quaternary arrangements of the receptor. These were then compared with published crystal structures of dimeric β1-adrenoreceptor, μ-opioid, and CXCR4 receptors. The data indicate important contributions of residues from within each of transmembrane domains I, II, IV, V, VI, and VII as well as the intracellular helix VIII in the formation of D3-D3 receptor interfaces within homo-oligomers and are consistent with the D3 receptor adopting a β1-adrenoreceptor-like quaternary arrangement. Specifically, results suggest that D3 protomers can interact with each other via at least two distinct interfaces: the first one comprising residues from transmembrane domains I and II along with those from helix VIII and a second one involving transmembrane domains IV and V. Moreover, rather than existing only as distinct dimeric species, the results are consistent with the D3 receptor also assuming a quaternary structure in which two transmembrane domain I-II-helix VIII dimers interact to form a "rhombic" tetramer via an interface involving residues from transmembrane domains VI and VII. In addition, the results also provide insights into the potential contribution of molecules of cholesterol to the overall organization and potential stability of the D3 receptor and possibly other GPCR quaternary structures., (© 2015 by The American Society for Biochemistry and Molecular Biology, Inc.)

Unlike formyl peptide receptor 1 (FPR1), FPR2/ALX (FPR2) interacts with peptides of diverse sequences but has low affinity for the Escherichia coli-derived chemotactic peptide fMet-Leu-Phe (fMLF). Using computer modeling and site-directed mutagenesis, we investigated the structural requirements for FPR2 to interact with formyl peptides of different length and composition. In calcium flux assay, the N-formyl group of these peptides is necessary for activation of both FPR2 and FPR1, whereas the composition of the C-terminal amino acids appears more important for FPR2 than FPR1. FPR2 interacts better with pentapeptides (fMLFII, fMLFIK) than tetrapeptides (fMLFK, fMLFW) and tripeptide (fMLF) but only weakly with peptides carrying negative charges at the C terminus (e.g. fMLFE). In contrast, FPR1 is less sensitive to negative charges at the C terminus. A CXCR4-based homology model of FPR1 and FPR2 suggested that Asp-281(7.32) is crucial for the interaction of FPR2 with certain formyl peptides as its negative charge may be repulsive with the terminal COO- group of fMLF and negatively charged Glu in fMLFE. Asp-281(7.32) might also form a stable interaction with the positively charged Lys in fMLFK. Site-directed mutagenesis was performed to remove the negative charge at position 281 in FPR2. The D281(7.32)G mutant showed improved affinity for fMLFE and fMLF and reduced affinity for fMLFK compared with wild type FPR2. These results indicate that different structural determinants are used by FPR1 and FPR2 to interact with formyl peptides.

Background: The CWxP motif of transmembrane helix 6 (x: any residue) is highly conserved in class A GPCRs. Within this motif, W6.48 is a big star in the theory of the global "toggle switch" because of its key role in the activation mechanism of GPCRs upon ligand binding. With all footlights focused on W6.48, the reason why the preceding residue, C6.47, is largely conserved is still unknown. The present study is aimed to fill up this lack of knowledge by characterizing the role of C6.47 of the CWxP motif., Results: A complete analysis of available crystal structures has been made alongside with molecular dynamics simulations of model peptides to explore a possible structural role for C6.47., Conclusions: We conclude that C6.47 does not modulate the conformation of the TM6 proline kink and propose that C6.47 participates in the rearrangement of the TM6 and TM7 interface accompanying activation.

Context: TSH receptor (TSHR) and thyroid peroxidase (TPO) gene mutations occur independently. This is the first report of their coexistence in the same individuals., Objectives: The objective of the study was to evaluate the genotype-phenotype correlations when mutations in both genes are present alone or together in the same individual., Patients and Methods: Thirty subjects from an extended Arab kindred underwent clinical investigation and molecular studies of the mutant TSHRs., Results: A novel mutant TSHR was identified, involving four nucleotides at three sites on the same allele, c.267G>T (L89L), c.269/270AG>CT (Q90P), and c.790C>T (P264S). In addition, two known TPO gene mutations, G493S and R540X, were identified. Thirteen heterozygotes for the mutant TSHR allele had mild hyperthyrotropinemia. In nine of theses, the coexistence of a TPO mutation in one allele did not magnify the hyperthyrotropinemia. Homozygotes for the mutant TSHR and a compound heterozygote for the TPO mutations presented frank hypothyroidism. In vitro studies showed increasing loss of function for Q90P less than P264S less than Q90P/P264S TSHR mutants, the latter being that expressed in the subjects under investigation. The two interchangeably used WT TSHR vectors, L87 and V87, although functionally identical, differed in structure and function in the presence of the Q90P mutation., Conclusions: TSHR and TPO gene mutations were identified alone and together in individuals of a consanguineous kindred. Homozygotes for the TSHR and a compound heterozygote for the TPO mutations were hypothyroid. The mild hyperthyrotropinemia of heterozygotes for the mutant TSHR allele was not aggravated by the coexistence of a TPO defect in one allele.

Rhodopsin is a prototypical heptahelical family A G-protein-coupled receptor (GPCR) responsible for dim-light vision. Light isomerizes rhodopsin's retinal chromophore and triggers concerted movements of transmembrane helices, including an outward tilting of helix 6 (H6) and a smaller movement of H5, to create a site for G-protein binding and activation. However, the precise temporal sequence and mechanism underlying these helix rearrangements is unclear. We used site-directed non-natural amino acid mutagenesis to engineer rhodopsin with p-azido-l-phenylalanine residues incorporated at selected sites, and monitored the azido vibrational signatures using infrared spectroscopy as rhodopsin proceeded along its activation pathway. Here we report significant changes in electrostatic environments of the azido probes even in the inactive photoproduct Meta I, well before the active receptor state was formed. These early changes suggest a significant rotation of H6 and movement of the cytoplasmic part of H5 away from H3. Subsequently, a large outward tilt of H6 leads to opening of the cytoplasmic surface to form the active receptor photoproduct Meta II. Thus, our results reveal early conformational changes that precede larger rigid-body helix movements, and provide a basis to interpret recent GPCR crystal structures and to understand conformational sub-states observed during the activation of other GPCRs.

The receptors for TSH, LH/chorionic gonadotropin (CG), and FSH belong to the same subfamily of G protein-coupled receptors. The specificity of recognition of their cognate hormone involves a limited number of residues in the leucine-rich repeats present in the N-terminal ectodomain of the receptor. It is admitted that receptors of this subfamily coevoluted with their respective ligands. The secretion of CG is restricted to gestation of primates and Equidae. We hypothesized that, facing the challenge of a new hormone, the glycoprotein hormone receptors would have evolved differently in Equidae and human so that distinct residues are involved in hormone specificity. In particular, it is known that equine CG has a dual (FSH and LH) activity when administered to other species. In the present work, we cloned and characterized functionally the equine TSH receptor (TSHR), which shares 89% homology with the human TSHR. The equine TSHR is not responsive to equine CG but is more sensitive to human CG than the human TSHR. Three residues, at positions 60, 229, and 235 of the ectodomain, are responsible for this difference in sensitivity as shown by modelization and targeted mutagenesis, followed by in vitro functional characterization. The phylogenetic approach is a suitable approach to identify determinants of specificity of receptors.