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Background Social media platforms such as YouTube™ have become a widely popular source for information regarding health-related issues about medical and dental issues. The simplicity of online watching has concealed the drawback that these videos are not regularly reviewed or checked for their suitability as educational resources for dental professionals and students. Aim The purpose of the current study was to evaluate the content and quality of videos on YouTube™ regarding maxillofacial prosthesis as a source of learning by dental professionals. Materials and Methods Fifty-one videos satisfying inclusion criteria were watched and carefully reviewed. After that, the following data were recorded in terms of domain in maxillofacial prosthesis: number of views, likes, comments, subscribers of the channel, viewing rate, duration since upload of video, video length/duration, primary purpose of videos, video sources, target group of video, video content, video content usefulness score, modified discern instrument score, and global quality score. Results No misleading video about said topic was uploaded during the period. Only 5.9% of the YouTube™ videos on maxillofacial prostheses were good. Conclusions There is a dearth of good-quality videos and videos about maxillofacial prosthesis maintenance, which raises questions if maxillofacial videos on YouTube™ would be equally beneficial for patients.

Abstract Aim The current study emphasizes the impact of adverse drug reactions (ADRs) and Drug-Related Problems (DRPs) caused by supportive care medications administered with chemotherapy. Method This is a longitudinal observational study carried out at the Ramaiah Medical College Hospital in Bengaluru, Karnataka, India, at the Department of Oncology. The data was recorded using a specifically created data collecting form. Based on the PCNE (Pharmaceutical Care Network Europe), DRPs are identified. The WHO probability scale, Modified Hartwig and Siegel for ADR severity assessment, Naranjo's algorithm for causality assessment, Rawlins and Thompson for predictability assessment, and Modified Shumock and Thornton for preventability assessment were all utilized. The OncPal guideline was considered in terms of the precision of supportive care medications regarding the reduction of ADRs in cancer patients. Result We enrolled 302 patients,166 (55%) female and 136 (45%) male (SD 14.378) (mean 49.97), patients with one comorbidity 59(19.6%) and multimorbidity (two or more) 45(14.9%), the DRPs identified were found to be 153 (50.6%); only P2 (safeties of drug therapy PCNE) were considered in this study. ADRs which are identified 175(57.9%) contributed/caused by the supportive care medications. WHO probability scale: 97 (32.1%) possible and 60 (19.9%) unlikely; Naranjo’s algorithm: 97 (32.1%) unlikely and 69 (22.8%) possible; ADR severity assessment scale (Modified Hartwig and Siegel): 95 (31.5%) mild and 63 (20.9%) moderates; Rawlins and Thompson for determining predictability of an ADR: 33 (10.9%) predictable and 137 (45.5%) non-predictable; and Modified Shumock and Thornton for determining preventability of an ADR: 81 (26.8%) probably preventable and 90 (29.8%) non-preventable. The statistical comparison through preforming t-test and measuring Chi-Square between group with ADRs and without ADRs shows in some variables, significantly (Alcohol consumption status, P = .019) and Easter Cooperative Oncology Group (ECOG) performance status P

Urbanization and climate change increase the frequency of urban floods worldwide which in turn poses a great challenge in the management of the urban stormwater drain system. This study investigated the impact of climate change and surface imperviousness in the urban stormwater runoff and the impact of washed off pollutants load in the conduit efficiency for two census wards Triplicane (ward 116) and Valasaravakkam (ward 152) in Chennai City. The climate change data for the study area wards were taken from the regional climate model (RCM) of Representative Concentration Pathway (RCP) 4.5. Storm Water Management Model (SWMM) with quality and quantity scenarios were developed and the results of the present year scenario were validated using a questionnaire survey. Intensity Duration Frequency (IDF) curves were generated to forecast the observed rainfall and climate model data for various return periods, i.e., 2, 5, 10, 50, and 100 years for future climatic scenarios (2030s and 2050s). The model results show that infiltration is only 3–7% of the total rainfall in the study areas and the maximum blockage and reduction in conduit capacity were estimated to be 65 and 40%, respectively. This paper presents the observations and suggestions for improving the conduit efficiency from an Integrated Water Management Approach (IWMA). HIGHLIGHTS Imperviousness of the study area was calculated based on LULC classification using Google Earth.; Bias correction was carried out for the climate data using observed rain gauge data.; Evaluation of the impact of pollutants load in the conduit carrying capacity using the SWMM.; Questionnaire survey outcomes were used to understand the past extreme events and also used in conjunction with the model outputs to derive suggestions.;

Production of waste cooking oil in big cities is a problem for public health in different countries around the world. A feasible solution is employing as raw material for biodiesel production. However, the problem is the high content of free fatty acids, moisture and solid particles presented in the oil. Therefore, this article analyses a process to treat Colombian waste cooking oils, by filtrating with a cellulose filter, drying with silica gel, and esterifying with methanol. For removing of particles it was standardized a process of filtration employing paper filter. With this process the solids remotion was 78.63%. After filtration oil was submitted to adsorption with silica gel. The experimental design was two concentration of adsorbent (0.025 g silica gel/ml oil and 0.11 g silica gel /ml oil) and two temperatures (15° C – 60°C). The best condition was temperature of 15 °C and a relation of 0.11 g silica gel /ml oil. The last step evaluated was esterification which to transform free fatty acid in methyl esters. In this reaction were evaluated two temperatures (40 °C and 60 °C), two concentration of sulfuric acid (1% w/w and 3% w/w) and two alcohol:oil molar relations (4:1 and 6:1). According to experimental results the best conditions were 60°C, 1% w/w sulfuric acid with 4:1 alcohol:oil molar relation during 2 hours. Finally oil obtained had less of 1% of moisture, 0.25% of solids suspended and1.38 mg KOH/g oil of acid value. These attributes satisfactorily meet with ASTM and ISO standards, so it will be possible to use as raw material for biodiesel production.

Single neutral pion production via muon antineutrino charged-current interactions in plastic scintillator (CH) is studied using the MINERvA detector exposed to the NuMI low-energy, wideband antineutrino beam at Fermilab. Measurement of this process constrains models of neutral pion production in nuclei, which is important because the neutral-current analog is a background for ν¯e appearance oscillation experiments. The differential cross sections for π0 momentum and production angle, for events with a single observed π0 and no charged pions, are presented and compared to model predictions. These results comprise the first measurement of the π0 kinematics for this process.

Several cylindrical specimens and dental implants, presenting diagonal lattice structures with different cell sizes (600, 900 and 1200 μm) were additively manufactured by selective laser melting process. Then they were implanted for two months in a sheep. After removal, they were studied by Archimedes’ method as well as X-ray computed tomography in order to assess the penetration of bone into the lattice. We observed that the additive manufactured parts were geometrically conformed to the theoretical specifications. However, several particles were left adhering to the surface of the lattice, thereby partly or entirely obstructing the cells. Nevertheless, bone penetration was clearly visible. We conclude that the 900 μm lattice cell size is more favourable to bone penetration than the 1200 μm lattice cell size, as the bone penetration is 84% for 900 μm against 54% for 1200 μm cell structures. The lower bone penetration value for the 1200 μm lattice cell could possibly be attributed to the short residence time in the sheep. Our results lead to the conclusion that lattice implants additively manufactured by selective laser melting enable better bone integration.

In order to test the validity of ultraviolet index (UVI) satellite products and UVI model simulations for general public information, intercomparison involving three satellite instruments (SCIAMACHY, OMI and GOME-2), the Chemistry and Transport Model, Modélisation de la Chimie Atmosphérique Grande Echelle (MOCAGE), and ground-based instruments was performed in 2008 and 2009. The intercomparison highlighted a systematic high bias of ~1 UVI in the OMI clear-sky products compared to the SCIAMACHY and TUV model clear-sky products. The OMI and GOME-2 all-sky products are close to the ground-based observations with a low 6 % positive bias, comparable to the results found during the satellite validation campaigns. This result shows that OMI and GOME-2 all-sky products are well appropriate to evaluate the UV-risk on health. The study has pointed out the difficulty to take into account either in the retrieval algorithms or in the models, the large spatial and temporal cloud modification effect on UV radiation. This factor is crucial to provide good quality UV information. OMI and GOME-2 show a realistic UV variability as a function of the cloud cover. Nevertheless these satellite products do not sufficiently take into account the radiation reflected by clouds. MOCAGE numerical forecasts show good results during periods with low cloud covers, but are actually not adequate for overcast conditions; this is why Météo-France currently uses human-expertised cloudiness (rather than direct outputs from Numerical Prediction Models) together with MOCAGE clear-sky UV indices for its operational forecasts. From now on, the UV monitoring could be done using free satellite products (OMI, GOME-2) and operational forecast for general public by using modelling, as long as cloud forecasts and the parametrisation of the impact of cloudiness on UV radiation are adequate.

Context.—: Increased band neutrophils in blood smear differential counts ("bandemia") are entrenched in medicine as a flag for sepsis. However, laboratory hematology experts have long advocated for discontinuation of reporting bands separately from segmented neutrophils because of poor sensitivity and specificity, poor interobserver agreement, and availability of alternative biomarkers for sepsis., Objective.—: To describe band neutrophil reporting practices and reproducibility of band classification among laboratories participating in the College of American Pathologists (CAP) proficiency testing (PT) program., Design.—: A survey questionnaire was distributed to hematology PT participants. A subsequent morphologic challenge included 12 preselected cell identifications of segmented neutrophils, bands, and metamyelocytes, and a 100-cell manual differential count of a digitally scanned blood smear., Results.—: Among laboratories that reported manual differentials, most respondents reported bands (4554 of 5268; 86.4%). Only 3222 of 4412 respondents (73.0%) provided band reference ranges. Though participants classified "easy" band neutrophils well (78.0%-98.3%), categorization of cell identifications for "moderate" and "difficult" bands was poor (3.1%-39.0% of laboratories), with classification instead as segmented neutrophils. This pattern was seen regardless of laboratory demographic characteristics. Marked variability in band counts was observed on the 100-cell differential count for both CAP PT participants and CAP Hematology and Clinical Microscopy Committee (HCMC) members (coefficients of variation, 55.8% and 32.9%, respectively). Variability was significantly improved when segmented and band neutrophils were grouped together (coefficients of variation, 6.2% and 5.0%, respectively)., Conclusions.—: Most CAP PT-participating laboratories report band counts, many without reference ranges. The survey confirms significant interlaboratory variability of band enumeration when bands are separately identified from segmented neutrophils. This study reaffirms the CAP Hematology and Clinical Microscopy Committee's strong recommendation to group segmented and band neutrophils together in manual differential counts., Competing Interests: All authors are past or present members of the College of American Pathologists Hematology and Clinical Microscopy subcommittee., (© 2024 College of American Pathologists.)

FMS-like tyrosine kinase 3 ( FLT3 ) mutations are detected in approximately 20-30% of patients with acute myeloid leukemia (AML), with the presence of a FLT3 internal tandem duplication ( FLT3 -ITD) mutation being associated with an inferior outcome. Assessment of FLT3 mutational status is now essential to define optimal upfront treatment in both newly diagnosed and relapsed AML, to support post-induction allogeneic hematopoietic stem cell transplantation (alloSCT) decision-making, and to evaluate treatment response via measurable (minimal) residual disease (MRD) evaluation. In view of its importance in AML diagnosis and management, the Canadian Leukemia Study Group/Groupe canadien d'étude sur la leucémie (CLSG/GCEL) undertook the development of a consensus statement on the clinical utility of FLT3 mutation testing, as members reported considerable inter-center variability across Canada with respect to testing availability and timing of use, methodology, and interpretation. The CLSG/GCEL panel identified key clinical and hematopathological questions, including: (1) which patients should be tested for FLT3 mutations, and when?; (2) which is the preferred method for FLT3 mutation testing?; (3) what is the clinical relevance of FLT3 -ITD size, insertion site, and number of distinct FLT3 -ITDs?; (4) is there a role for FLT3 analysis in MRD assessment?; (5) what is the clinical relevance of the FLT3 -ITD allelic burden?; and (6) how should results of FLT3 mutation testing be reported? The panel followed an evidence-based approach, taken together with Canadian clinical and laboratory experience and expertise, to create a consensus document to facilitate a more uniform approach to AML diagnosis and treatment across Canada.

Background: Preeclampsia (PE) is a hypertensive disorder during pregnancy that results in significant adverse maternal and neonatal outcomes. Platelet activation is present in PE and contributes to the thrombo-hemorrhagic states of the disorder. However, the mechanisms that initiate and/or sustain platelet activation in PE are ill-defined., Objectives: We aimed to characterise this mechanism and the procoagulant potentials of platelets in PE., Methods: In this quantitative observational study, we analyzed platelet procoagulant membrane dynamics in patients with PE (n = 21) compared with age-matched normotensive pregnancies (n = 20), gestational hypertension (n = 10), and non-pregnant female controls (n = 19). We analyzed fluorescently labeled indicators of platelet activation, bioenergetics, and procoagulation (phosphatidylserine exposure and thrombin generation), coupled with high-resolution imaging and thrombelastography. We then validated our findings using flow cytometry, immunoassays, classical pharmacology, and convolutional neural network analysis., Results: PE platelets showed significant ultra-structural remodeling, are more extensively preactivated than in healthy pregnancies and can circulate as microaggregates. Preactivated platelets of PE externalized phosphatidylserine and thrombin formed on the platelet membranes. Platelets' expression of facilitative glucose transporter-1 increased in all pregnant groups. However, PE platelets additionally overexpress glucose transporter-3 to enhance glucose uptake and sustain activation and secretion events. Although preeclampsia platelets exposed to subendothelial collagen showed incremental activation, the absolute hemostatic response to collagen was diminished, and likely contributed to greater blood loss perioperatively., Conclusions: We revealed 2 bioenergetic mediators in the mechanism of sustained platelet procoagulation in preeclampsia. Although glucose transporter-1 and glucose transporter-3 remain elusive antiprocoagulant targets, they may be sensitive monitors of PE onset and progression., Competing Interests: Declaration of competing interests E.O.A. holds a patent “Facilitative Glucose Transporters 1 And 3 as an Anti-Thrombotic and Diagnostic Target” US Prov (US 63/275767); and Canadian Patent Applic #: (3,137,826). Other authors report no competing interests., (Copyright © 2023 International Society on Thrombosis and Haemostasis. Published by Elsevier Inc. All rights reserved.)

Carpal tunnel syndrome (CTS) is common in patients with transthyretin amyloidosis (ATTR), and many experience residual symptoms and/or develop recurrent disease following routine carpal tunnel release (CTR). An extended CTR with median nerve neurolysis is recommended for thorough nerve decompression. Tissue confirmation of amyloidosis can be performed at the time of CTR with biopsies of the transverse carpal ligament and/or tenosynovium., Methods: We describe a retrospective, single-center experience performing an extended CTR technique including unilateral and bilateral cases for 13 consecutive patients (18 wrists) with ATTR and symptomatic median neuropathy at the wrist., Results: The mean patient age was 83 (range 67-90) years and 11 (85%) were men. Notable intraoperative findings in all cases included thickened tenosynovium and median nerve epineurium, and adherence of the median nerve to the deep surface of transverse carpal ligament. Pathology findings were positive for amyloidosis from both the transverse carpal ligament and the tenosynovium biopsies in all patients., Conclusions: Extended CTR with simultaneous wrist tissue biopsy can be safely performed for ATTR patients with CTS. Characteristic intraoperative findings should increase clinical suspicion for undiagnosed ATTR and prompt performance of biopsy for diagnostic confirmation. Volar wrist tenosynovial biopsy is our preferred tissue for confirmation of ATTR, for patients with and without CTS, given its safety profile and 100% pathological yield in our series., Competing Interests: Disclosure: The authors have no financial interest to declare in relation to the content of this article., (Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)

Severe acute respiratory syndrome coronavirus (SARS-CoV2) and associated COVID-19 infection continue to impact patients globally. Patients with underlying health conditions are at heightened risk of adverse outcomes from COVID-19; however, research involving patients with rare health conditions remains scarce. The amyloidoses are a rare grouping of protein deposition diseases. Light-chain and transthyretin amyloidosis are the most common disease forms, often present with systemic involvement of vital organs including the heart, nerves, kidneys, and GI tracts of affected individuals. The Amyloidosis Program of Calgary examined 152 ATTR patients and 103 AL patients analyzing rates of vaccination, COVID-19 testing, infection outcomes, influence referrals, and excess deaths. Results showed 15 total PCR-confirmed COVID-19 infections in the tested population of amyloid patients, with a higher frequency of infections among patient with AL compared to the ATTR cohort (26.2% vs 5.1%). Four patients (26.6%) required hospital admission for COVID-19 infection, 2 ATTR, and 2 AL patients. Of the confirmed cases, 1 (0.07%) unvaccinated ATTR patient died of a COVID-19 infection. An excess of deaths was found in both the ATTR and AL cohorts when comparing pre-pandemic years 2018 and 2019 to the pandemic years of 2020 and 2021. The finding suggests that amyloidosis patients are likely at a high risk for severe COVID-19 infection and mortality, especially those of advanced age, those on an active treatment with chemotherapy, and those with concomitant B-cell or plasma cell disorder. The impact of virtual healthcare visits and pandemic measures on the excess of deaths observed requires further research., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Context.—: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly infectious agent, with the propensity to cause severe illness. While vaccine uptake has been increasing in recent months, many regions remain at risk of significant coronavirus disease 19 (COVID-19)-related health care burden. Health systems will continue to benefit from the availability of a variety of clinical and laboratory models when other triaging models are equivocal., Objective.—: To validate previously reported clinical laboratory abnormalities seen in COVID-19 patients and identify what laboratory parameters might be outcome predictive., Design.—: We undertook an observational study of hospital-admitted COVID-19 patients (n = 113), looking at a broad selection of clinical, laboratory, peripheral blood smear, and outcome data during discrete discovery and validation periods from March 2020 to November 2020., Results.—: We confirmed the findings of previous studies noting derangement of a variety of laboratory parameters in COVID-19 patients, including peripheral blood morphologic changes. We also devised a simple-to-use decision tree by which patients could be risk stratified on the basis of red blood cell count, creatinine, urea, and atypical plasmacytoid lymphocyte ("covidocyte") count. This outcome classifier performed comparably to the World Health Organization clinical classifier and the neutrophil-lymphocyte ratio., Conclusions.—: Our data add to the increasing number of studies cataloguing laboratory changes in COVID-19 and support the clinical utility of incorporating blood morphologic assessment in the workup of hospitalized COVID-19 patients.

Dipeptidyl peptidase-4 inhibitors have been suspected to induce bullous pemphigoid (BP). The objective of this study was to compare the observed frequency of gliptin intake in a large sample of 1,787 BP patients diagnosed between 2012 and 2015 in France, with the expected frequency after indirect age standardization on 225,412 individuals extracted from the database of the National Healthcare Insurance Agency. The secondary objective was to assess the clinical characteristics and the course of gliptin-associated BP, depending on whether gliptin was continued or stopped. The observed frequencies of intake of the whole gliptin class and that of vildagliptin in the BP population were higher than those in the general population after age standardization (whole gliptin class: 6.0%; 95% confidence interval = 4.9-7.1% vs. 3.6%, observed-to-expected drug intake ratio = 1.7; 95% confidence interval = 1.4-2.0; P < 0.0001; vildagliptin = 3.3%; 95% confidence interval = 2.5-4.1% vs. 0.7%, ratio = 4.4; 95% confidence interval = 3.5-5.7; P < 0.0001). The association of any gliptin+metformin was also higher than in the general population, ratio = 1.8 (95% confidence interval = 1.3-2.4; P < 0.0001). Gliptin-associated BP had no specific clinical characteristics. Gliptin was stopped in 48 (45.3%) cases. Median duration to achieve disease control, rate, and delay of relapse were not different whether gliptin was stopped or continued. This study strongly supports the association between gliptin intake, particularly vildagliptin, and the onset of BP., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Hemophagocytic lymphohistiocytosis (HLH) is an uncommon systemic inflammatory condition that can result from infections, autoimmune diseases and malignancies. It is a rarely reported life threatening complication of an acute HIV infection, with only ten documented case reports per our literature search. We present a case of HLH secondary to acute HIV infection with a negative HIV antibody-based assay and high plasma viral load., Case Presentation: A 45 year old male with a past medical history of well controlled hypertension presented with fever, dizziness and non-bloody diarrhea. Initial lab work revealed a new thrombocytopenia, marked renal failure and an elevated creatine kinase, ferritin, lactate dehydrogenase and D-dimer. A bone marrow biopsy revealed HLH. As part of the work up for thrombocytopenia, a rapid HIV antibody based assay was done and was negative. The sample was later routinely tested with a fourth generation antigen/antibody assay as per local protocol and was strongly positive. The plasma RNA viral load was >10,000,000 copies /mL confirming the diagnosis of an acute HIV infection. The patient was urgently started on antiretroviral therapy and recovered., Conclusion: This case illustrates a diagnostic approach to HLH which is an uncommon but life threatening multisystem disease, requiring the involvement of a multidisciplinary team of experts. Following any diagnosis of HLH, rapid identification and treatment of the underlying condition is critical. A negative rapid HIV antibody test can be misleading in the context of early HIV infection and the additional use of fourth generation antigen/antibody test or plasma RNA viral load may be required within the right clinical context for diagnosis.

Background: Correlation of intraoperative frozen section diagnosis with final diagnosis can be an important component of an institution's quality assurance process., Methods: We performed a quality assurance review of 1207 frozen section diagnoses from 812 surgical cases performed in the Hamilton Regional Laboratory Medicine Programme during a 6-month period in 2007. We reviewed the frozen section and permanent slides from all potentially discordant cases using a multiheaded microscope to arrive at a consensus pertaining to the type and reason for error. We reviewed the clinical record to determine whether there had been a potential adverse impact on immediate clinical management., Results: Frozen sections were most commonly requested for head and neck, nervous system and female genital tract specimens. Twenty-eight frozen sections (3%) were deferred. We identified 24 discordant diagnoses involving 3% of cases and 2% of specimens. The organ systems showing the greatest frequency of discordance relative to the total number from that system were the nervous system, head and neck, and the lungs. Of the errors identified, most occurred owing to diagnostic misinterpretation, followed by problems related to tissue sampling. There was a potential adverse impact on immediate clinical management in 14 cases., Conclusion: Our results add to the Canadian data on the correlation between frozen sections and permanent sections; we note comparability to the concordance rates reported in the literature.

We report a case of littoral cell angioma (LCA) diagnosed by percutaneous core needle biopsy during the workup of a patient with multiple splenic lesions. Splenectomy was not performed. The patient has remained asymptomatic during 4 years of follow-up. Our findings raise interesting questions about the feasibility of core needle biopsy for the diagnosis of LCA. Clinicians should be aware of LCA as an unusual benign entity in the differential diagnosis of multiple splenic lesions.

Giant cell arteritis is a granulomatous vasculitis of large and medium sized arteries manifesting as temporal arteritis and/or polymyalgia rheumatica. The histological assessment of temporal artery biopsies is frequently encountered in anatomical pathology and has important diagnostic consequences in patients clinically suspected of having giant cell arteritis. We present an intriguing case of giant cell arteritis associated with a Basal cell carcinoma and discuss the ongoing controversy pertaining to the association of giant cell arteritis/polymyalgia rheumatica with malignancy.

The ovary shows an innate potential for markedly variable histogenesis, including squamous differentiation. Although not uncommon, squamous differentiation in ovarian lesions can be present in several diagnostic contexts, both benign and malignant. We present a review of the literature pertaining to squamous lesions of the ovary. In particular, we summarize the relevant clinical features, workup, gross findings and histopathologic features, differential diagnosis, treatment, and prognostic features of both the common and rare squamous entities found in the ovary.

A wide variety of noninfectious lesions have been identified in association with HIV infection. Many hematolymphoid lesions are possible in this patient group, both reactive and neoplastic. Epidemiologic data suggests that lymphoid malignancies are among the most common neoplasms in patients with HIV. We present a selective case series assembled over a 5-year period from the relatively low HIV-prevalence Hamilton Regional Laboratory Medicine Program (HRLMP), a tertiary care referral centre in Southern Ontario. This series serves to demonstrate the wide variety of lymphoid lesions that may be encountered in patients with HIV. In addition to outlining the pathologic work-up necessary in these cases, we discuss characteristics that distinguish the HIV-associated lesions from the pathobiologically similar non-HIV-associated lymphoid lesions.

The study of antagonist-binding domains of the human V1a vasopressin receptor was performed using a radioiodinated photoreactive peptide antagonist. This ligand displayed a high affinity for the receptor expressed in Chinese hamster ovary cell membranes, and specifically labeled two protein bands with apparent molecular mass at 85-90 and 46 kDa. Our results clearly show that the V1a receptor is degraded during incubation with the ligand and that the 46-kDa species is probably the result of the 85-90-kDa species proteolytic cleavage. Truncation of the receptor was then confirmed by deglycosylation with N-glycosidase F. A monoclonal antibody directed against a c-Myc epitope added at the receptor NH2 terminus allowed immunoprecipitation of the 85-90-kDa photolabeled species. The 46-kDa photolabeled protein never immunoprecipitated, indicating that the truncated form of the receptor lacks the NH2 terminus region. To localize photolabeled domains of the receptor, the 46-kDa protein was cleaved with V8 and/or Lys-C endoproteinases. The identity of the smallest photolabeled fragment, observed at approximately 6 kDa, was then confirmed by mutation of the potential V8 cleavage sites. Our results indicate that covalent labeling of the vasopressin V1a receptor with the photoreactive antagonist occurs in a region including transmembrane domain VII (residues Asn327-Lys370).

We report the isolation, characterization, and total synthesis of a small peptide ligand for nicotinic acetylcholine receptors (nAChRs). It is highly active against the neuromuscular receptor in frog but not in mice. In contrast, it induces seizures when injected centrally in mice and rats, suggesting that it may target neuronal nAChRs in mammals. Although such receptors may be important in both normal cognition and the pathophysiology of several neuropsychiatric disorders, there are few ligands to discriminate between the multiple receptor subtypes. The new peptide is a highly divergent alpha-conotoxin from the snail Conus imperialis, which preys on polychaete worms. In this article, the purification, structural analysis, synthesis, and preliminary physiological characterization of alpha-conotoxin ImI (alpha-CTx-ImI) are reported. The sequence of the peptide is: Gly-Cys-Cys-Ser-Asp-Pro-Arg-Cys-Ala-Trp-Arg-Cys-NH2. The peptide shows striking sequence differences from all alpha-conotoxins of fish-hunting Conus, but its disulfide-bridging is similar: [2-8; 3-12]. We suggest that cone venoms may provide an array of ligands with selectivity for various neuronal nAChR subtypes.