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1.
AJNR Am J Neuroradiol ; 41(5): 859-865, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32327436

RESUMO

BACKGROUND AND PURPOSE: The Neck Imaging Reporting and Data System was introduced to assess the probability of recurrence in surveillance imaging after treatment of head and neck cancer. This study investigated inter- and intrareader agreement in interpreting contrast-enhanced CT after treatment of oral cavity and oropharyngeal squamous cell carcinoma. MATERIALS AND METHODS: This retrospective study analyzed CT datasets of 101 patients. Four radiologists provided the Neck Imaging Reporting and Data System reports for the primary site and neck (cervical lymph nodes). The Kendall's coefficient of concordance (W), Fleiss κ (κF), the Kendall's rank correlation coefficient (τB), and weighted κ statistics (κw) were calculated to assess inter- and intrareader agreement. RESULTS: Overall, interreader agreement was strong or moderate for both the primary site (W = 0.74, κF = 0.48) and the neck (W = 0.80, κF = 0.50), depending on the statistics applied. Interreader agreement was higher in patients with proved recurrence at the primary site (W = 0.96 versus 0.56, κF = 0.65 versus 0.30) or in the neck (W = 0.78 versus 0.56, κF = 0.41 versus 0.29). Intrareader agreement was moderate to strong or almost perfect at the primary site (range τB = 0.67-0.82, κw = 0.85-0.96) and strong or almost perfect in the neck (range τB = 0.76-0.86, κw = 0.89-0.95). CONCLUSIONS: The Neck Imaging Reporting and Data System used for surveillance contrast-enhanced CT after treatment of oral cavity and oropharyngeal squamous cell carcinoma provides acceptable score reproducibility with limitations in patients with posttherapeutic changes but no cancer recurrence.


Assuntos
Neoplasias Orofaríngeas/diagnóstico por imagem , Carcinoma de Células Escamosas de Cabeça e Pescoço/diagnóstico por imagem , Adulto , Idoso , Conjuntos de Dados como Assunto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos
2.
QJM ; 113(11): 807-808, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32251500
3.
Blood Cancer J ; 7(4): e554, 2017 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-28430175

RESUMO

Carfilzomib, a proteasome inhibitor, is approved as monotherapy and in combination with dexamethasone or lenalidomide-dexamethasone (Rd) for relapsed or refractory multiple myeloma. The approval of carfilzomib-lenalidomide-dexamethasone (KRd) was based on results from the randomized, phase 3 study ASPIRE (NCT01080391), which showed KRd significantly improved progression-free survival (PFS) vs Rd (median 26.3 vs 17.6 months; hazard ratio (HR)=0.690; P=0.0001). This subgroup analysis of ASPIRE evaluated KRd vs Rd by number of previous lines of therapy and previous exposure to bortezomib, thalidomide or lenalidomide. Treatment with KRd led to a 12-month improvement in median PFS vs Rd after first relapse (HR 0.713) and a 9-month improvement after ⩾2 previous lines of therapy (HR 0.720). Treatment with KRd led to an approximate 8-month improvement vs Rd in median PFS in bortezomib-exposed patients (HR 0.699), a 15-month improvement in thalidomide-exposed patients (HR 0.587) and a 5-month improvement in lenalidomide-exposed patients (HR 0.796). Objective response and complete response or better rates were higher with KRd vs Rd, irrespective of previous treatment. KRd had a favorable benefit-risk profile and should be considered an appropriate treatment option for patients with 1 or ⩾2 previous lines of therapy and those previously exposed to bortezomib, thalidomide or lenalidomide.


Assuntos
Dexametasona/administração & dosagem , Mieloma Múltiplo/tratamento farmacológico , Oligopeptídeos/administração & dosagem , Talidomida/análogos & derivados , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Intervalo Livre de Doença , Feminino , Humanos , Lenalidomida , Masculino , Pessoa de Meia-Idade , Mieloma Múltiplo/patologia , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/patologia , Talidomida/administração & dosagem , Resultado do Tratamento
4.
Anaesthesia ; 72(2): 214-222, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27804117

RESUMO

Atelectasis occurs in the majority of children undergoing general anaesthesia. Lung ultrasound has shown reliable sensitivity and specificity for diagnosing anaesthesia-induced atelectasis. We assessed the effects of a recruitment manoeuvre on atelectasis using lung ultrasound in infants undergoing general anaesthesia. Forty infants, randomly allocated to either a recruitment manoeuvre group or a control group, received volume-controlled ventilation with 5 cmH2 O positive end-expiratory pressure. Lung ultrasound examination was performed twice in each patient, the first a minute after starting mechanical ventilation of the lungs and the second at the end of surgery. Patients in the recruitment manoeuvre group received ultrasound-guided recruitment manoeuvres after each lung ultrasound examination. The incidence of significant anaesthesia-induced atelectasis at the second lung ultrasound examination was less in the recruitment manoeuvre group compared with the control group (25% vs. 80%; p = 0.001; odds ratio (OR) 0.083; 95% confidence interval (CI): 0.019-0.370). The median (IQR [range]) lung ultrasound scores for consolidation and B-lines on the second examination were lower in the recruitment manoeuvre group compared with the control group; 6.0 (3.0-9.3 [0.0-14.0]) vs. 13.5 (11.0-16.5 [8.0-23.0]); p < 0.001 and 6.5 (3.0-12.0 [0.0-28.0]) vs. 15.0 (10.8-20.5 [7.0-28.0]); p < 0.001, respectively. The lung ultrasound scores for consolidation on the first and second examinations showed a negative correlation with age (r = -0.340, p = 0.008; r = -0.380, p = 0.003). We conclude that ultrasound-guided recruitment manoeuvres with positive end-expiratory pressure proved useful in reducing the incidence of anaesthesia-induced atelectasis in infants, although 5 cmH2 O positive end-expiratory pressure alone was not sufficient to eliminate it. In addition, the younger the patient, the more susceptible they were to atelectasis.


Assuntos
Anestesia Geral/efeitos adversos , Pulmão/diagnóstico por imagem , Atelectasia Pulmonar/prevenção & controle , Ultrassonografia , Feminino , Humanos , Lactente , Masculino , Respiração com Pressão Positiva , Estudos Prospectivos , Atelectasia Pulmonar/diagnóstico por imagem
5.
Cell Death Dis ; 6: e2011, 2015 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-26633717

RESUMO

Serum response factor (SRF) is a transcription factor known to mediate phenotypic plasticity in smooth muscle cells (SMCs). Despite the critical role of this protein in mediating intestinal injury response, little is known about the mechanism through which SRF alters SMC behavior. Here, we provide compelling evidence for the involvement of SRF-dependent microRNAs (miRNAs) in the regulation of SMC apoptosis. We generated SMC-restricted Srf inducible knockout (KO) mice and observed both severe degeneration of SMCs and a significant decrease in the expression of apoptosis-associated miRNAs. The absence of these miRNAs was associated with overexpression of apoptotic proteins, and we observed a high level of SMC death and myopathy in the intestinal muscle layers. These data provide a compelling new model that implicates SMC degeneration via anti-apoptotic miRNA deficiency caused by lack of SRF in gastrointestinal motility disorders.


Assuntos
Mucosa Intestinal/metabolismo , MicroRNAs/metabolismo , Fator de Resposta Sérica/metabolismo , Animais , Apoptose , Diferenciação Celular , Proliferação de Células , Humanos , Intestinos/citologia , Intestinos/patologia , Camundongos , Miócitos de Músculo Liso , Transdução de Sinais
6.
Neurogastroenterol Motil ; 27(8): 1089-97, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26088415

RESUMO

BACKGROUND: Functional dyspepsia (FD) is one of the most common disorders of gastrointestinal (GI) diseases. However, no curable treatment is available for FD because the detailed mechanism of GI dysfunction in stressed conditions remains unclear. We aimed to clarify the association between endogenous acylated ghrelin signaling and gastric motor dysfunction and explore the possibility of a drug with ghrelin signal-enhancing action for FD treatment. METHODS: Solid gastric emptying (GE) and plasma acylated ghrelin levels were evaluated in an urocortin1 (UCN1) -induced stress model. To clarify the role of acylated ghrelin on GI dysfunction in the model, exogenous acylated ghrelin, an endogenous ghrelin enhancer, rikkunshito, or an α2 -adrenergic receptor (AR) antagonist was administered. Postprandial motor function was investigated using a strain gauge force transducer in a free-moving condition. KEY RESULTS: Exogenous acylated ghrelin supplementation restored UCN1-induced delayed GE. Alpha2 -AR antagonist and rikkunshito inhibited the reduction in plasma acylated ghrelin and GE in the stress model. The action of rikkunshito on delayed GE was blocked by co-administration of the ghrelin receptor antagonist. UCN1 decreased the amplitude of contraction in the antrum while increasing it in the duodenum. The motility index of the antrum but not the duodenum was significantly reduced by UCN1 treatment, which was improved by acylated ghrelin or rikkunshito. CONCLUSIONS & INFERENCES: The UCN1-induced gastric motility dysfunction was mediated by abnormal acylated ghrelin dynamics. Supplementation of exogenous acylated ghrelin or enhancement of endogenous acylated ghrelin secretion by rikkunshito may be effective in treating functional GI disorders.


Assuntos
Medicamentos de Ervas Chinesas/administração & dosagem , Esvaziamento Gástrico/efeitos dos fármacos , Gastroenteropatias/prevenção & controle , Grelina/administração & dosagem , Estresse Psicológico/complicações , Antagonistas de Receptores Adrenérgicos alfa 2/farmacologia , Animais , Gastroenteropatias/complicações , Grelina/sangue , Masculino , Contração Muscular/efeitos dos fármacos , Oligopeptídeos/farmacologia , Período Pós-Prandial/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Receptores de Grelina/antagonistas & inibidores , Estresse Psicológico/induzido quimicamente , Urocortinas , Ioimbina/farmacologia
7.
Biochem Biophys Res Commun ; 345(4): 1342-9, 2006 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-16723117

RESUMO

K(V)11.1 (HERG) channels contribute to membrane potential in a number of excitable cell types. We cloned a variant of K(V)11.1 from human jejunum containing a 171 bp deletion spanning exons 3 and 4. Expression of a full-length cDNA clone containing this deletion gave rise to protein that trafficked to the cell membrane and generated robust currents. The deletion occurred in a G/C-rich region and identical sequence elements of UGGUGG were located at the deletion boundaries. In recent studies these features have been implicated to cause deletions via template switching during cDNA synthesis. To examine this possibility we compared cDNAs from human brain, heart, and jejunum synthesized at lower (42 degrees C) and higher temperatures (70 degrees C). The 171 bp deletion was absent at the higher temperature. Our results suggest that the sequence and secondary structure of mRNA in the G/C rich region leads to template switching producing a cDNA product with a 171 bp deletion.


Assuntos
Éxons/genética , Canais de Potássio de Abertura Dependente da Tensão da Membrana/genética , Transcrição Gênica/genética , Sequência de Aminoácidos , Sequência de Bases , Encéfalo/metabolismo , Linhagem Celular , DNA Complementar/genética , DNA Complementar/metabolismo , Perfilação da Expressão Gênica , Histidina/genética , Histidina/imunologia , Humanos , Jejuno/metabolismo , Potenciais da Membrana/genética , Potenciais da Membrana/fisiologia , Microscopia Confocal , Dados de Sequência Molecular , Miocárdio/metabolismo , Conformação de Ácido Nucleico , RNA/química , RNA/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Deleção de Sequência , Temperatura , Moldes Genéticos , Transfecção
8.
Neurogastroenterol Motil ; 17(4): 575-84, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16078947

RESUMO

Adenosine triphosphate (ATP) mediates excitatory junction potentials through P2X receptors in many smooth muscles. However, relatively little is known about postjunctional intestinal P2X receptors. We examined the effect of exogenous ATP on circular and longitudinal myocytes of canine colon using the patch clamp technique at 32 degrees C. In both cell types, ATP induced inward currents (I(ATP)) at -70 mV in a concentration-dependent manner. The potency profile of ATP analogues in circular myocytes was: ATP approximately 2-methylthio-ATP > alpha,beta-methylene ATP, and that in longitudinal myocytes was: alpha,beta-methylene ATP approximately ATP > 2-methylthio-ATP. Pretreatment of circular myocytes with alpha,beta-methylene ATP inhibited the response to subsequent ATP, suggesting receptor desensitization. I-V relationships of I(ATP) were linear with inward rectification and E(rev) of -13 mV. I(ATP) at -70 mV was carried predominantly by Na+ as determined by shifts in E(rev) when extracellular Na+ was lowered. In RT-PCR, circular myocytes expressed mRNAs encoding P2X2, 3 and 4, while longitudinal myocytes expressed mRNAs for P2X3 and 5. P2X7 was absent in both cells. Fragments of each subtype were cloned and sequenced. We failed to clone P2X1 and P2X6 genes. Overall, different P2X receptor subtypes are expressed in circular and longitudinal canine colonic myocytes. Their activation produces non-selective cation currents that can depolarize and excite muscles of both layers.


Assuntos
Trifosfato de Adenosina/metabolismo , Colo/fisiologia , Miócitos de Músculo Liso/fisiologia , Receptores Purinérgicos P2/fisiologia , Sequência de Aminoácidos , Animais , Encéfalo/fisiologia , Cães , Humanos , Potenciais da Membrana , Dados de Sequência Molecular , Contração Muscular/fisiologia , Técnicas de Patch-Clamp , Isoformas de Proteínas/fisiologia , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência
9.
Cell Mol Life Sci ; 62(11): 1198-220, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15798894

RESUMO

Phosphodiesterases (PDEs) are essential regulators of cyclic nucleotide signaling with diverse physiological functions. Because of their great market potential and therapeutic importance, PDE inhibitors became recognized as important therapeutic agents in the treatment of various diseases. Currently, there are seven PDE inhibitors on the market, and the pharmacological and safety evaluations of many drug candidates are in progress. Three-dimensional (3D) structures of catalytic domains of PDE 1, -3, -4, -5 and -9 in the presence of their inhibitors are now available, and can be utilized for rational drug design. Recent advances in molecular pharmacology of PDE isoenzymes resulted in identification of new potential applications of PDE inhibitors in various therapeutic areas, including dementia, depression and schizophrenia. This review will describe the latest advances in PDE research on 3D structural studies, the potential of therapeutic applications and the development of drug candidates.


Assuntos
Desenho de Fármacos , Inibidores de Fosfodiesterase , Diester Fosfórico Hidrolases , Doença , Tratamento Farmacológico , Humanos , Modelos Moleculares , Inibidores de Fosfodiesterase/química , Inibidores de Fosfodiesterase/farmacologia , Inibidores de Fosfodiesterase/uso terapêutico , Diester Fosfórico Hidrolases/química , Diester Fosfórico Hidrolases/efeitos dos fármacos , Estrutura Terciária de Proteína , Relação Estrutura-Atividade
10.
Am J Physiol Gastrointest Liver Physiol ; 284(6): G883-95, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12736144

RESUMO

Previous studies suggest that ether-a-go-go related gene (ERG) KCNH2 potassium channels contribute to the control of motility patterns in the gastrointestinal tract of animal models. The present study examines whether these results can be translated into a role in human gastrointestinal muscles. Messages for two different variants of the KCNH2 gene were detected: KCNH2 V1 human ERG (HERG) (28) and KCNH2 V2 (HERG(USO)) (13). The amount of V2 message was greater than V1 in both human jejunum and brain. The base-pair sequence that gives rise to domains S3-S5 of the channel was identical to that previously published for human KCNH2 V1 and V2. KCNH2 protein was detected immunohistochemically in circular and longitudinal smooth muscle and enteric neurons but not in interstitial cells of Cajal. In the presence of TTX (10(-6) M), atropine (10(-6) M). and l-nitroarginine (10(-4) M) human jejunal circular muscle strips contracted phasically (9 cycles/min) and generated slow waves with superimposed spikes. Low concentrations of the KCNH2 blockers E-4031 (10(-8) M) and MK-499 (3 x 10(-8) M) increased phasic contractile amplitude and the number of spikes per slow wave. The highest concentration of E-4031 (10(-6) M) produced a 10-20 mV depolarization, eliminated slow waves, and replaced phasic contractions with a small tonic contracture. E-4031 (10(-6) M) did not affect [(14)C]ACh release from enteric neurons. We conclude that KCNH2 channels play a fundamental role in the control of motility patterns in human jejunum through their ability to modulate the electrical behavior of smooth muscle cells.


Assuntos
Proteínas de Transporte de Cátions , Proteínas de Ligação a DNA , Regulação da Expressão Gênica , Jejuno/metabolismo , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Canais de Potássio/genética , Canais de Potássio/metabolismo , Transativadores , Acetilcolina/farmacologia , Processamento Alternativo , Sequência de Aminoácidos , Sequência de Bases , Benzopiranos/farmacologia , Canais de Cálcio/metabolismo , Relação Dose-Resposta a Droga , Canal de Potássio ERG1 , Canais de Potássio Éter-A-Go-Go , Humanos , Técnicas In Vitro , Potenciais da Membrana/efeitos dos fármacos , Contração Muscular/efeitos dos fármacos , Músculo Liso/metabolismo , Piperidinas/farmacologia , Potássio/metabolismo , Cloreto de Potássio/farmacologia , Piridinas/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Alinhamento de Sequência , Fatores de Tempo , Regulador Transcricional ERG
11.
Bioorg Med Chem Lett ; 11(23): 3069-72, 2001 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-11714612

RESUMO

Design, synthesis and structure-activity relationship of a class of aryl pyrroles as farnesyltransferase inhibitors are described. In vitro and in vivo evaluation of a panel of these inhibitors led to identification of 2 (LB42908) as a highly potent (IC(50)=0.9 nM against H-Ras and 2.4 nM against K-Ras) antitumor agent that is currently undergoing preclinical studies.


Assuntos
Alquil e Aril Transferases/antagonistas & inibidores , Antineoplásicos/química , Antineoplásicos/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Imidazóis/química , Imidazóis/farmacologia , Piperazinas/química , Piperazinas/farmacologia , Animais , Relação Dose-Resposta a Droga , Desenho de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Concentração Inibidora 50 , Camundongos , Camundongos Nus , Peptídeos/química , Relação Estrutura-Atividade , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
12.
Bioorg Med Chem Lett ; 11(22): 2963-5, 2001 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-11677136

RESUMO

Design, synthesis and structure-activity relationship of a class of 3-aryl-4-aryloyl-1-(1H-imidazol-5-yl)methylpyrroles as farnesyltransferase inhibitors are described. Compound 7 inhibits farnesyltransferase with an IC(50) value of 4.6 nM.


Assuntos
Alquil e Aril Transferases/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Imidazóis/síntese química , Pirróis/síntese química , Desenho de Fármacos , Inibidores Enzimáticos/química , Farnesiltranstransferase , Imidazóis/farmacologia , Concentração Inibidora 50 , Pirróis/farmacologia , Relação Estrutura-Atividade
14.
J Biol Chem ; 276(47): 44338-46, 2001 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-11560940

RESUMO

Potassium channels activated by membrane stretch may contribute to maintenance of relaxation of smooth muscle cells in visceral hollow organs. Previous work has identified K(+) channels in murine colon that are activated by stretch and further regulated by NO-dependent mechanisms. We have screened murine gastrointestinal, vascular, bladder, and uterine smooth muscles for the expression of TREK and TRAAK mRNA. Although TREK-1 was expressed in many of these smooth muscles, TREK-2 was expressed only in murine antrum and pulmonary artery. TRAAK was not expressed in any smooth muscle cells tested. Whole cell currents from TREK-1 expressed in mammalian COS cells were activated by stretch, and single channel recordings showed that the stretch-dependent conductance was due to 90 pS channels. Sodium nitroprusside (10(-6) or 10(-5) m) and 8-Br-cGMP (10(-4) or 10(-3) m) increased TREK-1 currents in perforated whole cell and single channel recordings. Mutation of the PKG consensus sequence at serine 351 blocked the stimulatory effects of sodium nitroprusside and 8-Br-cGMP on open probability without affecting the inhibitory effects of 8-Br-cAMP. TREK-1 encodes a component of the stretch-activated K(+) conductance in smooth muscles and may contribute to nitrergic inhibition of gastrointestinal muscles.


Assuntos
Proteínas Quinases Dependentes de GMP Cíclico/fisiologia , Músculo Liso/fisiologia , Óxido Nítrico/fisiologia , Canais de Potássio de Domínios Poros em Tandem , Canais de Potássio/fisiologia , Transmissão Sináptica/fisiologia , Animais , Sequência de Bases , Células COS , GMP Cíclico/farmacologia , Primers do DNA , Camundongos , Camundongos Endogâmicos BALB C , Músculo Liso/efeitos dos fármacos , Músculo Liso/inervação , Mutagênese Sítio-Dirigida , Nitroprussiato/farmacologia , Técnicas de Patch-Clamp , Reação em Cadeia da Polimerase Via Transcriptase Reversa
15.
Am J Physiol Gastrointest Liver Physiol ; 281(4): G964-73, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11557517

RESUMO

Small-conductance Ca2+-activated K+ (SK) channels are important participants in inhibitory neurotransmission in gastrointestinal smooth muscles. Three isoforms of an SK channel family were cloned from murine proximal colon smooth muscle. The transcripts encoding these subunits (SK1, SK2, and SK3) were detected in murine proximal colon and other peripheral tissues. The mRNA of each subunit was expressed at different levels in murine and canine colonic smooth muscles. The mRNA quantitative ratio of SK transcriptional expression in murine proximal colon is SK2 > SK3 > SK1; transcriptional expression of SK isoforms in canine proximal colon is minimal. SK3 immunohistochemical localization in murine small intestine (jejunum) and proximal colon showed immunoreactivity in circular and longitudinal muscularis. In transversely sectioned muscularis, staining was localized at the cell membrane in smooth muscle cells. Immunoreactivity was more intense in myenteric ganglia between longitudinal and circular muscularis and neuronal processes in circular and longitudinal muscularis. Transient expression of mSK1, mSK2, and mSK3 in COS cells resulted in Ca2+-activated voltage-independent channels. mSK1 is less sensitive to apamin compared with SK2 and showed intracellular Ca2+ sensitivity (10(-8) to 10(-6) M) in asymmetrical K+ (5/140 mM K+) gradients. Our results suggest that SK channel expression varies in colonic myocytes from different species and may contribute differentially to inhibitory junction potentials.


Assuntos
Cálcio/metabolismo , Colo/fisiologia , Músculo Liso/fisiologia , Canais de Potássio/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Células COS , Clonagem Molecular , Cães , Humanos , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Técnicas de Patch-Clamp , Canais de Potássio/química , Canais de Potássio/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Transmissão Sináptica/fisiologia , Distribuição Tecidual
16.
J Physiol ; 533(Pt 2): 341-55, 2001 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-11389196

RESUMO

1. Two components of voltage-gated, inward currents were observed from murine colonic myocytes. One component had properties of L-type Ca(2+) currents and was inhibited by nicardipine (5 x 10(-7) M). A second component did not 'run down' during dialysis and was resistant to nicardipine (up to 10(-6) M). The nicardipine-insensitive current was activated by small depolarizations above the holding potential and reversed near 0 mV. 2. This low-voltage-activated current (I(LVA)) was resolved with step depolarizations positive to -60 mV, and the current rapidly inactivated upon sustained depolarization. The voltage of half-inactivation was -65 mV. Inactivation and activation time constants at -45 mV were 86 and 15 ms, respectively. The half-recovery time from inactivation was 98 ms at -45 mV. I(LVA) peaked at -40 mV and the current reversed at 0 mV. 3. I(LVA) was inhibited by Ni(2+) (IC(50) = 1.4 x 10(-5) M), mibefradil (10(-6) to 10(-5) M), and extracellular Ba(2+). Replacement of extracellular Na(+) with N-methyl-D-glucamine inhibited I(LVA) and shifted the reversal potential to -7 mV. Increasing extracellular Ca(2+) (5 x 10(-3) M) increased the amplitude of I(LVA) and shifted the reversal potential to +22 mV. I(LVA) was also blocked by extracellular Cs(+) (10(-4) M) and Gd(3+) (10(-6) M). 4. Warming increased the rates of activation and deactivation without affecting the amplitude of the peak current. 5. We conclude that the second component of voltage-dependent inward current in murine colonic myocytes is not a 'T-type' Ca(2+) current but rather a novel, voltage-gated non-selective cation current. Activation of this current could be important in the recovery of membrane potential following inhibitory junction potentials in gastrointestinal smooth muscle or in mediating responses to agonists.


Assuntos
Canais de Cálcio Tipo L/fisiologia , Colo/citologia , Ativação do Canal Iônico/fisiologia , Músculo Liso/fisiologia , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Animais , Bário/farmacologia , Cálcio/farmacocinética , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo T/genética , Césio/farmacologia , Gadolínio/farmacologia , Expressão Gênica , Ativação do Canal Iônico/efeitos dos fármacos , Mibefradil/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Músculo Liso/citologia , Músculo Liso/inervação , Inibição Neural/fisiologia , Nicardipino/farmacologia , Níquel/farmacologia , Técnicas de Patch-Clamp , Sódio/farmacologia , Temperatura
17.
Bioorg Med Chem ; 9(7): 1837-41, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11425585

RESUMO

We have attempted to design a model dipeptide (acetyl dipeptide amide, Ac-CA1-CA2--NH(2)) that can adopt specifically typical torsion angles of the beta-I turn (phi(i+1), psi(i+1), phi(i+2), psi(i+2)=-60 degrees, -30 degrees, -90 degrees, 0 degrees ). The key of the design is the combination of constrained amino acids that prefer to adopt the desired torsion angles. We chose Aib (aminoisobutyric acid) as the first residue of which phi and psi angles must be -60 degrees and -30 degrees, respectively. Then, we selected an azaamino acid as the second residue since previous studies have indicated that they prefer to adopt +/-90 degrees of phi angle and 0 degrees or 180 degrees of psi angle. The conformational preference of the resulting Ac-Aib-AzGly--NH(2) is investigated using ab initio methods. The conformations implying beta-I and beta-I' turns are energetically most favorable, as we expected. Thus, we synthesized the designed molecule on the solid phase considering the future generation of combinatorial libraries using an automatic peptide synthesizer. Then, NMR spectroscopy was carried out to confirm their conformational preference in solution was carried out. The results indicated that the Ac-Aib-AzGly--NH(2) adopt beta-I or beta-I' turns in solution forming an intramolecular hydrogen bonding between Ac--C(O) and terminal NH(2). We believe that such a small peptidomimetic template is highly useful for the design of drug candidates and molecular devices.


Assuntos
Dipeptídeos/química , Mimetismo Molecular , Dipeptídeos/síntese química , Ressonância Magnética Nuclear Biomolecular , Estrutura Secundária de Proteína
18.
Kansenshogaku Zasshi ; 74(10): 816-23, 2000 Oct.
Artigo em Japonês | MEDLINE | ID: mdl-11109763

RESUMO

Using 92 Salmonella strains isolated from patients suspected of having infectious diseases of the intestinal tract who visited 13 hospitals in Japan during the six years between 1991 and 1996, we investigated the drug susceptibility, prevalence of conjugative R plasmid, and the plasmid profiles. 1) Of the bacterial isolates tested, 52.2% showed drug-resistance. Regarding the drug-resistance patterns, 70.8% of the isolates were resistant to a single drug, while 29.2% were multi drug-resistant. 2) Dividing the resistance patterns by the serotypes, among Salmonella Enteritidis isolates, single-drug resistance to SM was the most frequent, being detected in 27 isolates. Single-drug resistance to NA and two-drug resistance to SM/TC were the second-most frequent, each being detected in isolates. Among Salmonella Hadar isolates, four isolates showed two-drug resistance to SM/TC, and one isolate showed single-drug resistance to TC. Among Salmonella Typhimurium isolates, one isolate each showed three-drug resistance to ABPC/CER/KM and KM/TC/CP. Among Salmonella Agona isolates, one isolate each showed two-drug resistance to SM/TC and single-drug resistance to SM. Among Salmonella Derby isolates, two isolates showed single-drug resistance to SM. 3) The prevalence of conjugative R plasmid was investigated in 48 drug-resistant isolates, and six isolates (12.5%) contained the plasmid. 4) The prevalence of the plasmid was investigated in 29 drug-resistant S. Enteritidis isolates, and 22 isolates (75.9%) contained the plasmid. These isolated were classified by the plasmid profiles into types H1 to H7. 5) Regarding the plasmid profiles of the S. Enteritidis isolates, a position corresponding to 60 Kbp was the most frequently detected in 90.5%.


Assuntos
Antibacterianos/farmacologia , Enterite/microbiologia , Fatores R , Salmonella/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Salmonella/classificação , Salmonella/isolamento & purificação
19.
Org Lett ; 2(16): 2411-4, 2000 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-10956509

RESUMO

The reversible nature of the imine bond formation in CDCl(3) solution has been exploited to exchange substituted for unsubstituted m-phenylenediamine (MPD) units in hemicarcerand octaimines. Moreover, acid-catalyzed imine exchange has been shown to provide a novel mechanism whereby ferrocene (Fc) can be released as an entrapped guest from the hemicarceplex C(2)B(4)&crcldt;Fc dissolved in CDCl(3) to give the hemicarcerand C(2)B(4) when excess of both MPD and trifluoroacetic acid are present.


Assuntos
Éteres Cíclicos/síntese química , Iminas/síntese química , Fenilenodiaminas/química , Éteres Cíclicos/química , Iminas/química , Modelos Moleculares , Conformação Molecular , Relação Estrutura-Atividade , Termodinâmica
20.
J Pept Res ; 56(1): 35-46, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10917455

RESUMO

The structural perturbation induced by C(alpha)-->N(alpha) exchange in azaamino acid-containing peptides was predicted by ab initio calculation of the 6-31G* and 3-21G* levels. The global energy-minimum conformations for model compounds, For-azaXaa-NH2 (Xaa=Gly, Ala, Leu) appeared to be the beta-turn motif with a dihedral angle of phi= +/- 90 degrees, psi=0 degrees. This suggests that incorporation of the azaXaa residue into the i+2 position of designed peptides could stabilize the beta-turn structure. The model azaLeu-containing peptide, Boc-Phe-azaLeu-Ala-OMe, which is predicted to adopt a beta-turn conformation was designed and synthesized in order to experimentally elucidate the role of the azaamino acid residue. Its structural preference in organic solvents was investigated using 1H NMR, molecular modelling and IR spectroscopy. The temperature coefficients of amide protons, the characteristic NOE patterns, the restrained molecular dynamics simulation and IR spectroscopy defined the dihedral angles [ (phi i+1, psi i+1) (phi i+2, psi i+2)] of the Phe-azaLeu fragment in the model peptide, Boc-Phe-azaLeu-Ala-OMe, as [(-59 degrees, 127 degrees) (107 degrees, -4 degrees)]. This solution conformation supports a betaII-turn structural preference in azaLeu-containing peptides as predicted by the quantum chemical calculation. Therefore, intercalation of the azaamino acid residue into the i+2 position in synthetic peptides is expected to provide a stable beta-turn formation, and this could be utilized in the design of new peptidomimetics adopting a beta-turn scaffold.


Assuntos
Compostos Aza/síntese química , Oligopeptídeos/síntese química , Compostos Aza/química , Compostos Aza/metabolismo , Dipeptídeos/química , Desenho de Fármacos , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética , Modelos Químicos , Modelos Moleculares , Estrutura Molecular , Oligopeptídeos/química , Oligopeptídeos/metabolismo , Estrutura Secundária de Proteína , Solventes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
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