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BACKGROUND: Disseminated intravascular coagulation (DIC) has been recognized as an urgent and critical condition in patients with sepsis. Therefore, unfamiliar and time-consuming tests or a complex scoring system are not suitable for diagnosis. Sepsis-induced coagulopathy (SIC), a newly proposed category delineated by a few global coagulation tests, has been established as an early warning sign for DIC. The purpose of this study was to elucidate the characteristics of SIC, especially in relation to the score of the International Society on Thrombosis and Haemostasis (ISTH) for overt DIC. METHOD: A data set for 332 patients with sepsis who were suspected to have DIC, antithrombin activity <70%, and treated with antithrombin substitution was utilized to examine the relationship between SIC and overt DIC. The performance of SIC calculated at baseline (ie, before treatment) as well as on days 2, 4, or 7 was analyzed in terms of its ability to predict 28-day mortality and overt DIC. RESULTS: At baseline, 149 (98.7%) of 151 patients with overt DIC according to the ISTH definition were diagnosed as having SIC. Of the 49, 46 (93.9%) patients who developed overt DIC between days 2 and 4 had received a prior diagnosis of SIC. The sensitivity of baseline SIC for the prediction of death was significantly higher than that of overt DIC (86.8% vs 64.5%, P < .001). The sensitivity of SIC on days 2, 4, and 7 was significantly higher than those of overt DIC (96.1%, 92.3%, and 84.4% vs 67.1%, 57.7%, and 50.0%, P < .001, .001, and .001, respectively), although the specificity of SIC was lower at all time points.
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Testes de Coagulação Sanguínea/estatística & dados numéricos , Cuidados Críticos/estatística & dados numéricos , Coagulação Intravascular Disseminada/diagnóstico , Sepse/mortalidade , Índice de Gravidade de Doença , Idoso , Idoso de 80 Anos ou mais , Antitrombinas/sangue , Testes de Coagulação Sanguínea/métodos , Cuidados Críticos/métodos , Resultados de Cuidados Críticos , Coagulação Intravascular Disseminada/etiologia , Coagulação Intravascular Disseminada/mortalidade , Diagnóstico Precoce , Feminino , Fibrinolíticos/uso terapêutico , Humanos , Masculino , Valor Preditivo dos Testes , Vigilância de Produtos Comercializados , Sepse/complicaçõesRESUMO
The 25 bitter taste receptors (T2Rs) in humans perform a chemosensory function. However, very little is known about the level of expression of these receptors in different tissues. In this study, using nCounter gene expression we analyzed the expression patterns of human TAS2R transcripts in cystic fibrosis bronchial epithelial (CuFi-1), normal bronchial epithelial (NuLi-1), airway smooth muscle (ASM), pulmonary artery smooth muscle (PASM), mammary epithelial, and breast cancer cells. Our results suggest a specific pattern of TAS2R expression with TAS2R3, 4, 5, 10, 13, 19, and 50 transcripts expressed at moderate levels and TAS2R14 and TAS2R20 (or TASR49) at high levels in the various tissues analyzed. This pattern of expression is mostly independent of tissue origin and the pathological state, except in cancer cells. To elucidate the expression at the protein level, we pursued flow cytometry analysis of select T2Rs from CuFi-1 and NuLi-1 cells. The expression levels observed at the gene level by nCounter analysis correlate with the protein levels for the T2Rs analyzed. Next, to assess the functionality of the expressed T2Rs in these cells, we pursued functional assays measuring intracellular calcium mobilization after stimulation with the bitter compound quinine. Using PLC inhibitor, U-73122, we show that the calcium mobilized in these cells predominantly takes place through the Quinine-T2R-Gαßγ-PLC pathway. This report will accelerate studies aimed at analyzing the pathophysiological function of T2Rs in different extraoral tissues.
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Brônquios/metabolismo , Regulação da Expressão Gênica/fisiologia , Músculo Liso/metabolismo , Receptores Acoplados a Proteínas G/biossíntese , Mucosa Respiratória/metabolismo , Sinalização do Cálcio/fisiologia , Humanos , Especificidade de Órgãos/fisiologiaRESUMO
Fabry disease is a rare inherited X-linked metabolic disorder in which deficient alpha-galactosidase A activity causes progressive build-up of globotriaosylceramide (Gb3) and multi-system dysfunction. Following approval of agalsidase alfa for Fabry disease in Japan in 2006, an 8-year all-case post-marketing surveillance (PMS) showed that the treatment was well tolerated and effective for managing disease progression in adult Japanese patients. The present nationwide prospective observational study extended the initial PMS by enrolling patients who continued agalsidase alfa treatment after the initial 8-year period in a 6.5-year extension survey. Patient information from the initial PMS and the extension survey was evaluated as a single data set (observation period: February 2007-September 2021). Of 493 patients in the initial PMS, 129 (45.0% male classic, 6.2% male non-classic, 48.8% female heterozygous phenotype) consented to participate in the extension survey and were included in the analysis. The mean duration of treatment was 9.6 years. A total of 145 adverse drug reactions (ADRs) occurred in 31 patients (24%), and 22 serious ADRs occurred in 12 patients (9.3%). Although serious cardiac, renal, or cerebrovascular adverse events decreased in frequency over time in male patients, serious cardiac events continued to occur in female patients, who showed higher incidence of cardiac complications at baseline. No new safety concerns were identified. Additionally, long-term agalsidase alfa treatment sustained the initial reduction in Gb3 concentrations without increasing the rate of anti-agalsidase antibody positivity. These findings suggest that agalsidase alfa treatment demonstrates continued safety and sustains patients' clinical course over the long term.
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Objective The efficacy of maintenance intravenous immunoglobulin (IVIg) therapy has been established to prevent relapse in chronic inflammatory demyelinating polyneuropathy (CIDP). This prospective post-marketing surveillance study evaluated the treatment duration, efficacy, and safety of maintenance IVIg therapy in Japanese patients with CIDP. Methods Patients were registered between June 2017 and December 2018. After induction of IVIg therapy (0.4 g/kg/day for 5 consecutive days), patients received maintenance IVIg (1.0 g/kg every 3 weeks). The observation period was 18 months. Efficacy in preventing relapse was assessed using the Inflammatory Neuropathy Cause and Treatment (INCAT) disability score. Relapse was defined as a worsening of the INCAT score by ≥1 from baseline. Patients The efficacy population comprised 103 patients (80 with typical CIDP and 23 with CIDP variants). Results During the observation period, 86 (83%) patients were scheduled to continue maintenance IVIg therapy during the observation period, and the relapse rate was 24% (21/86). In the remaining 17 patients who showed continuous remission, maintenance IVIg therapy was stopped (mean, 136 days after the start), and the relapse rate was 24% (4/17). One serious adverse drug reaction of cardiac failure was reported. Conclusion In this post-marketing surveillance, most (83%) patients with CIDP were scheduled to continue maintenance IVIg for 18 months, with a relapse rate of 24%, indicating long-term efficacy. Maintenance IVIg therapy was rarely withdrawn, and the relapse rate after withdrawal was 24%. Further studies are required to determine the optimal maintenance IVIg dose and duration.
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BACKGROUND: In Japan, intravenous immunoglobulin (IVIG) has been approved for corticosteroid-unresponsive bullous pemphigoid (BP); however, its usage, efficacy, and safety in clinical settings remain unclear. OBJECTIVE: To elucidate IVIG efficacy, we examined the improvement in disease severity based on the Bullous Pemphigoid Disease Area Index (BPDAI). METHODS: In this 3-year (April 2016-March 2019), prospective, post-marketing, observational surveillance study, we enrolled 379 patients (51.3 % men; mean age, 74.5 years) with corticosteroid-unresponsive BP treated with IVIG from 143 institutions in Japan (720 treatment cycles). The percentage of patients who improved by at least one severity stage or whose symptoms completely resolved based on the BPDAI score was evaluated at 15, 30, and 60-90 days. RESULTS: The improvement rates at 15, 30, and 60-90 days after initial treatment in the 328 IVIG-naïve patients were 70.7 %, 83.5 %, and 84.3 %, respectively. The BPDAI score decreased rapidly and significantly by 15 days compared with that observed during pre-treatment. Further improvement was observed at 30 and 60-90 days. The corticosteroid dose and anti-BP180 antibody titers decreased significantly post-treatment (both, p < .001). Approximately 25 % of IVIG-naïve patients underwent multiple treatment cycles. The improvement rate at 30 days after the final dose was 88 %, and the symptoms completely resolved in 44 % of patients. The incidence of adverse drug reactions per cycle was 8.34 %; the most common reaction was transient thrombocytopenia. CONCLUSION: Most patients showed improvement in severity and decrease in corticosteroid dose and anti-BP180 antibody levels post-treatment, indicating that IVIG is useful for corticosteroid-unresponsive BP treatment.
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Penfigoide Bolhoso , Masculino , Humanos , Idoso , Feminino , Imunoglobulinas Intravenosas/uso terapêutico , Estudos Prospectivos , Japão , Autoanticorpos , Corticosteroides/uso terapêutico , Vigilância de Produtos Comercializados , AutoantígenosRESUMO
Sequence analysis of the class A G protein-coupled receptors (GPCRs) reveals that most of the highly conserved sites are located in the transmembrane helices. A second level of conservation exists involving those residues that are conserved as a group characterized by small and/or weakly polar side chains (Ala, Gly, Ser, Cys, Thr). These positions can have group conservation levels of up to 99% across the class A GPCRs and have been implicated in mediating helix-helix interactions in membrane proteins. We have previously shown that mutation of group-conserved residues present on transmembrane helices H2-H4 in the ß(2)-adrenergic receptor (ß(2)-AR) can influence both receptor expression and function. We now target the group-conserved sites, Gly315(7.42) and Ser319(7.46), on H7 for structure-function analysis. Replacing Ser319(7.46) with smaller amino acids (Ala or Gly) did not influence the ability of the mutant receptors to bind to the antagonist dihydroalprenolol (DHA) but resulted in ~15-20% agonist-independent activity. Replacement of Ser319(7.46) with the larger amino acid leucine lowered the expression of the S319L mutant and its ability to bind DHA. Both the G315A and G315S mutants also exhibited agonist-independent signaling, while the G315L mutant did not show specific binding to DHA. These data indicate that Gly315(7.42) and Ser319(7.46) are stabilizing ß(2)-AR in an inactive conformation. We discuss our results in the context of van der Waals interactions of Gly315(7.42) with Trp286(6.48) and hydrogen bonding interactions of Ser319(7.46) with amino acids on H1-H2-H7 and with structural water.
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Aminoácidos/metabolismo , Estrutura Secundária de Proteína , Receptores Adrenérgicos beta 2/metabolismo , Relação Estrutura-Atividade , Agonistas Adrenérgicos beta/metabolismo , Agonistas Adrenérgicos beta/farmacologia , Antagonistas Adrenérgicos beta/metabolismo , Antagonistas Adrenérgicos beta/farmacologia , Substituição de Aminoácidos , Aminoácidos/química , Aminoácidos/genética , Animais , Sítios de Ligação/genética , Células COS , Chlorocebus aethiops , Cricetinae , AMP Cíclico/metabolismo , Di-Hidroalprenolol/metabolismo , Di-Hidroalprenolol/farmacologia , Glicina/química , Glicina/genética , Glicina/metabolismo , Células HEK293 , Humanos , Ligação de Hidrogênio , Isoproterenol/metabolismo , Isoproterenol/farmacologia , Modelos Moleculares , Mutação , Ligação Proteica/efeitos dos fármacos , Estrutura Terciária de Proteína , Ensaio Radioligante , Receptores Adrenérgicos beta 2/química , Receptores Adrenérgicos beta 2/genética , Serina/química , Serina/genética , Serina/metabolismoRESUMO
PURPOSE: The change in the sequential organ failure assessment (SOFA) score from the entry day, a delta-SOFA (SOFAΔ), has been proposed as a better indicator for predicting mortality, and potentially as an endpoint in clinical trials. However, there are some concerns that the value of the absolute SOFA score has not been considered. The purpose of the study is to examine whether the addition of an absolute SOFA score can increase the predictive performance of SOFAΔ. MATERIALS AND METHODS: Data obtained from 297 patients with sepsis-associated disseminated intravascular coagulopathy (DIC) in multiinstitutional post-marketing surveys were analyzed retrospectively. The SOFAComb (SOFAΔ score + absolute SOFA score) and SOFAΔ were calculated, and the performance of each indicator was analyzed in terms of predictive ability for 28-day mortality. RESULTS: The area under the receiver operating curve (AUC) for the mortality of SOFAComb on day 2, 4, 7 were significantly greater compared to those of SOFAΔ (P <0.001, =0.002, <0.001, respectively). In addition, the accuracy [(True positive + True negative) / total number at the best cutoff points] of SOFAComb was better than that of SOFAΔ. CONCLUSIONS: SOFAComb is simple to calculate and provides better predictive performance compared to SOFAΔ for predicting mortality.
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Escores de Disfunção Orgânica , Sepse , Humanos , Prognóstico , Curva ROC , Estudos RetrospectivosRESUMO
The primary end point for sepsis trial is 28-day mortality. However, additional methods for determining the efficacy may have benefits. The purpose of this study was to search a useful indicator of anticoagulant therapy in patients with sepsis with disseminated intravascular coagulation (DIC). Data from 323 patients with sepsis with coagulopathy treated with antithrombin supplementation were analyzed. The changes in the Sequential Organ Failure Assessment (Δ SOFA) score, the overt-DIC (Δ overt-DIC) score, and the Japanese Society for Acute Medicine DIC (Δ JAAM DIC) score from baseline to day 7 were retrospectively analyzed in relation to the 28-day mortality. Significant correlations were found between the 28-day mortality and Δ SOFA, Δ overt-DIC score, and Δ JAAM DIC score. The accuracy of the prediction was higher for Δ SOFA (80.5%) than for Δ overt-DIC (66.7%, P < .001). The areas under the curve for mortality calculated using a receiver operating characteristic curve analysis were 0.812 for Δ SOFA, 0.655 for Δ overt-DIC, and 0.693 for Δ JAAM DIC. The mortality rate was significantly lower among cases with an improved SOFA score compared to those without an improvement. The Δ SOFA had the strongest association with the 28-day mortality in patients with sepsis and DIC.
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Coagulação Intravascular Disseminada/mortalidade , Escores de Disfunção Orgânica , Sepse/mortalidade , Idoso , Coagulação Intravascular Disseminada/sangue , Feminino , Humanos , Masculino , Mortalidade , Sepse/sangueRESUMO
For success in clinical trials, eliminating inclusion of patients with irreversible recovery is important. The purpose of this study was to identify the patient population who do not survive for more than 3 days. A total of 449 patients with sepsis suspected of having disseminated intravascular coagulation (DIC) and treated with antithrombin were examined. The patient characteristics, baseline sequential organ failure assessment (SOFA) score, DIC score, and hemostatic markers were retrospectively analyzed in relation to early death (died within 3 days). At the end of day 3, a total of 419 patients had survived and 30 patients had died. A logistic regression analysis revealed a significant association between early death and the baseline prothrombin time-international normalized ratio PT-INR (P <.05) and the total SOFA score (P <.01). In contrast, neither the platelet count, fibrinogen/fibrin degradation products, and antithrombin activity nor the DIC score was associated with early death. Although the accuracy for predicting early death defined by either baseline PT-INR of ≥1.57 or total SOFA score of more than 13 was not high enough, that of "high-risk of early death (PT-INR ≥ 1.57 and SOFA score ≥ 13)" was 83.5%. Furthermore, the negative predictive of this category was 96.0%. The baseline SOFA score and PT-INR were associated with early death among patients with sepsis-associated coagulation disorders. Patients who do not meet the "high-risk of early death" criteria were likely to survive for more than 3 days and therefore should be considered for future therapeutic clinical trials.
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Antitrombinas/administração & dosagem , Coagulação Intravascular Disseminada , Sepse , Idoso , Idoso de 80 Anos ou mais , Antitrombinas/farmacocinética , Coagulação Intravascular Disseminada/sangue , Coagulação Intravascular Disseminada/diagnóstico , Coagulação Intravascular Disseminada/tratamento farmacológico , Coagulação Intravascular Disseminada/mortalidade , Feminino , Produtos de Degradação da Fibrina e do Fibrinogênio , Humanos , Coeficiente Internacional Normatizado , Masculino , Escores de Disfunção Orgânica , Contagem de Plaquetas , Valor Preditivo dos Testes , Tempo de Protrombina , Sepse/sangue , Sepse/diagnóstico , Sepse/tratamento farmacológico , Sepse/mortalidadeRESUMO
Disseminated intravascular coagulation (DIC) in patients with sepsis represents a critical condition. Thus, a simple and rapid diagnosis is required. The purpose of this study was to compare the performances of a recently developed Sepsis-Induced Coagulopathy (SIC) with the Japanese Association for Acute Medicine (JAAM) DIC. Four hundred nine patients with sepsis having coagulopathy and antithrombin activity of less than 70% and treated with antithrombin were retrospectively analyzed, and the SIC and JAAM-DIC criteria on days 1 (before treatment), 2, 4, and 7 were compared. The prevalence of JAAM-DIC on day 1 was significantly higher than that of SIC (91.4% vs 81.8%, P = .003), but there were no differences on days 2, 4, and 7. The mortality rates in the SIC and JAAM-DIC groups were both 23.3%. The specificity to 28-day mortality on day 1 was higher in the SIC group (15.8% vs 9.2%, P = .013). There were no differences in sensitivity on days 1, 2, 4, and 7. Mortality was significantly different between SIC-positive and SIC-negative groups on days 2, 4, and 7 ( P < .01, respectively), while significant differences were seen between JAAM-DIC-positive and JAAM-DIC-negative groups only on days 4 and 7 ( P < .05, .01, respectively). In summary, the SIC characteristics were similar to the JAAM-DIC group, and the classifications were comparable in terms of mortality prediction. The SIC scoring system is simple, easy to use, and adaptable to the new sepsis definitions and offers an important approach to evaluating patients in emergency and critical care settings.
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Antitrombinas/uso terapêutico , Transtornos da Coagulação Sanguínea/complicações , Coagulação Intravascular Disseminada/sangue , Sepse/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Povo Asiático , Feminino , Humanos , Masculino , Sepse/sangueRESUMO
Over the past decade tremendous progress has been made in understanding the functional role of bitter taste receptors (T2Rs) and bitter taste perception. This review will cover the recent advances made in identifying the role of T2Rs in pathophysiological states. T2Rs are widely expressed in various parts of human anatomy and have been shown to be involved in physiology of respiratory system, gastrointestinal tract and endocrine system. Empirical evidence has shown T2Rs to be an integral component of antimicrobial immune responses in upper respiratory tract infections. The studies on human airway smooth muscle cells have shown that a potent bitter tastant induced bronchodilatory effects mediated by bitter taste receptors. Clinical data suggests a role for T2R38 polymorphism in predisposition of individuals to chronic rhinosinusitis. The role of genetic variation in T2Rs and its impact on disease susceptibility have been investigated in various other disease risk factors such as alcohol dependence, head and neck cancers. Preliminary reports have demonstrated differential expression of functional T2Rs in breast cancer cell lines. Studies on the role of T2Rs in pathophysiology of diseases including chronic rhinosinusitis, asthma, cystic fibrosis, and cancer have been promising. However, research in this field is in its nascent stages, and more confirmatory studies on animal models and in clinical settings are required.
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Doença , Receptores Acoplados a Proteínas G/metabolismo , Animais , Humanos , Receptores Acoplados a Proteínas G/químicaRESUMO
[reaction: see text] Bicyclo[4.3.0]nonanes (hydrindanes) and bicyclo[3.3.0]octanes (octahydropentalenes) are easily synthesized by palladium-catalyzed cycloalkenylations. Additionally, benzo-fused bicyclo[3.3.0]octanes are prepared for the first time through intramolecular coupling between silyl enol ethers and aromatic rings in the presence of catalytic palladium acetate.
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This study evaluated the pulpal response and in-vivo microleakage of a flowable composite bonded with a self-etching adhesive and compared the results with a glass ionomer cement and amalgam. Cervical cavities were prepared in monkey teeth. The teeth were randomly divided into three groups. A self-etching primer system (Imperva FluoroBond, Shofu) was applied to the teeth in one of the experimental groups, and the cavities were filled with a flowable composite (SI-BF-2001-LF, Shofu). In the other groups, a glass ionomer cement (Fuji II, GC) or amalgam (Dispersalloy, Johnson & Johnson) filled the cavity. The teeth were then extracted after 3, 30 and 90 days, fixed in 10% buffered formalin solution and prepared according to routine histological techniques. Five micrometer sections were stained with hematoxylin and eosin or Brown and Brenn gram stain for bacterial observation. No serious inflammatory reaction of the pulp, such as necrosis or abscess formation, was observed in any of the experimental groups. Slight inflammatory cell infiltration was the main initial reaction, while deposition of reparative dentin was the major long-term reaction in all groups. No bacterial penetration along the cavity walls was detected in the flowable composite or glass ionomer cement except for one case at 30 days in the glass ionomer cement. The flowable composite bonded with self-etching adhesive showed an acceptable biological com- patibility to monkey pulp. The in vivo sealing ability of the flowable composite in combination with the self-etching adhesive was considered comparable to glass ionomer cement. Amalgam restorations without adhesive liners showed slight bacterial penetration along the cavity wall.
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Materiais Biocompatíveis/química , Resinas Compostas/química , Cobre/química , Amálgama Dentário/química , Colagem Dentária , Adesivos Dentinários/química , Cimentos de Ionômeros de Vidro/química , Análise de Variância , Animais , Ligas Dentárias/química , Corrosão Dentária , Infiltração Dentária/classificação , Infiltração Dentária/microbiologia , Polpa Dentária/patologia , Dentina Secundária/patologia , Macaca , Teste de Materiais , Distribuição Aleatória , Fatores de TempoRESUMO
Pulp tissue reactions to a fluoride-releasing all-in-one resin bonding system (Reactmer Bond and Reactmer Paste) in non-exposed monkey teeth were histopathologically evaluated at three, 30, and 90 days after restoration. No serious inflammatory reactions of the pulp, such as necrosis or abscess formation, were observed. At 90 days in the Reactmer group, odontoblastic change and inflammatory cell infiltration were not observed, and slight irritation dentin formation was formed. The pulpal response of the Reactmer group was minimally different from that of the control group. Consequently, the Reactmer system was determined as being biologically compatible with vital pulps.
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Cariostáticos/farmacologia , Colagem Dentária , Polpa Dentária/efeitos dos fármacos , Fluoretos/farmacologia , Cimentos de Ionômeros de Vidro/química , Abscesso/classificação , Análise de Variância , Animais , Materiais Biocompatíveis/química , Cariostáticos/química , Resinas Compostas/química , Intervalos de Confiança , Necrose da Polpa Dentária/classificação , Restauração Dentária Permanente , Dentina Secundária/efeitos dos fármacos , Fluoretos/química , Macaca , Odontoblastos/efeitos dos fármacos , Pulpite/classificação , Distribuição Aleatória , Cimentos de Resina/química , Estatística como Assunto , Estatísticas não Paramétricas , Fatores de TempoRESUMO
PURPOSE: To evaluate an auto-cured resin as a direct pulp capping material on exposed pulp with or without a self-etching primer. MATERIALS AND METHODS: Class V cavities were prepared on the facial surfaces of 90 intact monkey teeth, and the pulps were intentionally exposed with a carbide bur through the cavity floor. Each exposed pulp was capped with a commercially available adhesive resin system (Clearfil Liner Bond 2V: Group LB) or an auto-cured sealant resin (Teethmate-S) with and without the use of a self-etching primer (Group TMP and Group TM, respectively). The cavities were restored with an adhesive resin and a hybrid resin-based composite (Clearfil AP-X). Inflammatory cell infiltration and dentin bridge formation of the exposed pulp as well as protrusion of the exposed pulp tissue into the cavities were evaluated histologically at 3, 30 and 90 days. RESULTS: Slight inflammatory cell infiltration was the main inflammatory reaction of the exposed pulp, and the exposed area became occluded with dentin bridges as the observation period increased. However, significantly higher incidence of slight inflammatory cell infiltration was found in Group TM than in Group LB at 30 days (P<0.05). Group TM showed significantly higher incidence of protrusion of pulp tissue than Groups LB and TMP through all tested periods (P<0.05).
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Materiais Biocompatíveis/farmacologia , Cimentos Dentários/farmacologia , Capeamento da Polpa Dentária/métodos , Polpa Dentária/efeitos dos fármacos , Selantes de Fossas e Fissuras/farmacologia , Condicionamento Ácido do Dente , Animais , Materiais Biocompatíveis/uso terapêutico , Resinas Compostas/farmacologia , Polpa Dentária/patologia , Capeamento da Polpa Dentária/efeitos adversos , Exposição da Polpa Dentária/terapia , Dentina Secundária/efeitos dos fármacos , Estudos de Avaliação como Assunto , Haplorrinos , Inflamação/patologia , Teste de Materiais , Metacrilatos/farmacologia , Resistência à TraçãoRESUMO
G-protein coupled receptors (GPCRs) are transmembrane signaling molecules, with a majority of them performing important physiological roles. beta(2)-Adrenergic receptor (beta(2)-AR) is a well-studied GPCRs that mediates natural responses to the hormones adrenaline and noradrenaline. Analysis of the ligand-binding region of beta(2)-AR using the recently solved high-resolution crystal structures revealed a number of highly conserved amino acids that might be involved in ligand binding. However, detailed structure-function studies on some of these residues have not been performed, and their role in ligand binding remains to be elucidated. In this study, we have investigated the structural and functional role of a highly conserved residue valine 114, in hamster beta(2)-AR by site-directed mutagenesis. We replaced V114 in hamster beta(2)-AR with a number of amino acid residues carrying different functional groups. In addition to the complementary substitutions V114I and V114L, the V114C and V114E mutants also showed significant ligand binding and agonist dependent G-protein activation. However, the V114G, V114T, V114S, and V114W mutants failed to bind ligand in a specific manner. Molecular modeling studies were conducted to interpret these results in structural terms. We propose that the replacement of V114 influences not only the interaction of the ethanolamine side-chains but also the aryl-ring of the ligands tested. Results from this study show that the size and orientation of the hydrophobic residue at position V114 in beta(2)-AR affect binding of both agonists and antagonists, but it does not influence the receptor expression or folding.
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Receptores Adrenérgicos beta 2/química , Valina/química , Adenilil Ciclases/metabolismo , Antagonistas Adrenérgicos beta/farmacologia , Alprenolol/farmacologia , Animais , Sítios de Ligação , Células COS , Chlorocebus aethiops , Cricetinae , AMP Cíclico/metabolismo , Modelos Moleculares , Mutagênese Sítio-Dirigida , Ligação Proteica/efeitos dos fármacos , Receptores Adrenérgicos beta 2/genética , Receptores Adrenérgicos beta 2/metabolismo , Valina/metabolismoRESUMO
A metal-free acetylide was observed by using NMR spectroscopy. Metal-free acetylides are closely related to reactive intermediates (carbanions) in solution; therefore, they have been regarded as unobservable species. However, we generated this highly reactive and unstable species through the deprotonation of phenylacetylene by using the strong nonmetallic phosphazene base tBu-P4. In the presence of tBu-P4, the J coupling between the ethynyl carbon and hydrogen nuclei (1J(C,H)) of phenylacetylene disappeared; this indicates the deprotonation of the alkyne terminal. Furthermore, a large low-field shift (approximately 90 ppm) of the alkyne carbon resonance was observed. We concluded that we have observed a metal-free carbanion with a formal charge on an sp-hybridized carbon atom for the first time.