RESUMEN
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.
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Neoplasias Orofaríngeas/diagnóstico por imagen , Carcinoma de Células Escamosas de Cabeza y Cuello/diagnóstico por imagen , Adulto , Anciano , Conjuntos de Datos como Asunto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Estudios Retrospectivos , Tomografía Computarizada por Rayos X/métodosRESUMEN
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.
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Dexametasona/administración & dosificación , Mieloma Múltiple/tratamiento farmacológico , Oligopéptidos/administración & dosificación , Talidomida/análogos & derivados , Adulto , Anciano , Anciano de 80 o más Años , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Supervivencia sin Enfermedad , Femenino , Humanos , Lenalidomida , Masculino , Persona de Mediana Edad , Mieloma Múltiple/patología , Recurrencia Local de Neoplasia/tratamiento farmacológico , Recurrencia Local de Neoplasia/patología , Talidomida/administración & dosificación , Resultado del TratamientoRESUMEN
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.
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Anestesia General/efectos adversos , Pulmón/diagnóstico por imagen , Atelectasia Pulmonar/prevención & control , Ultrasonografía , Femenino , Humanos , Lactante , Masculino , Respiración con Presión Positiva , Estudios Prospectivos , Atelectasia Pulmonar/diagnóstico por imagenRESUMEN
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.
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Mucosa Intestinal/metabolismo , MicroARNs/metabolismo , Factor de Respuesta Sérica/metabolismo , Animales , Apoptosis , Diferenciación Celular , Proliferación Celular , Humanos , Intestinos/citología , Intestinos/patología , Ratones , Miocitos del Músculo Liso , Transducción de SeñalRESUMEN
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.
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Medicamentos Herbarios Chinos/administración & dosificación , Vaciamiento Gástrico/efectos de los fármacos , Enfermedades Gastrointestinales/prevención & control , Ghrelina/administración & dosificación , Estrés Psicológico/complicaciones , Antagonistas de Receptores Adrenérgicos alfa 2/farmacología , Animales , Enfermedades Gastrointestinales/complicaciones , Ghrelina/sangre , Masculino , Contracción Muscular/efectos de los fármacos , Oligopéptidos/farmacología , Periodo Posprandial/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Receptores de Ghrelina/antagonistas & inhibidores , Estrés Psicológico/inducido químicamente , Urocortinas , Yohimbina/farmacologíaRESUMEN
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.
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Exones/genética , Canales de Potasio con Entrada de Voltaje/genética , Transcripción Genética/genética , Secuencia de Aminoácidos , Secuencia de Bases , Encéfalo/metabolismo , Línea Celular , ADN Complementario/genética , ADN Complementario/metabolismo , Perfilación de la Expresión Génica , Histidina/genética , Histidina/inmunología , Humanos , Yeyuno/metabolismo , Potenciales de la Membrana/genética , Potenciales de la Membrana/fisiología , Microscopía Confocal , Datos de Secuencia Molecular , Miocardio/metabolismo , Conformación de Ácido Nucleico , ARN/química , ARN/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Eliminación de Secuencia , Temperatura , Moldes Genéticos , TransfecciónRESUMEN
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.
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Adenosina Trifosfato/metabolismo , Colon/fisiología , Miocitos del Músculo Liso/fisiología , Receptores Purinérgicos P2/fisiología , Secuencia de Aminoácidos , Animales , Encéfalo/fisiología , Perros , Humanos , Potenciales de la Membrana , Datos de Secuencia Molecular , Contracción Muscular/fisiología , Técnicas de Placa-Clamp , Isoformas de Proteínas/fisiología , ARN Mensajero/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Homología de SecuenciaRESUMEN
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.
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Diseño de Fármacos , Inhibidores de Fosfodiesterasa , Hidrolasas Diéster Fosfóricas , Enfermedad , Quimioterapia , Humanos , Modelos Moleculares , Inhibidores de Fosfodiesterasa/química , Inhibidores de Fosfodiesterasa/farmacología , Inhibidores de Fosfodiesterasa/uso terapéutico , Hidrolasas Diéster Fosfóricas/química , Hidrolasas Diéster Fosfóricas/efectos de los fármacos , Estructura Terciaria de Proteína , Relación Estructura-ActividadRESUMEN
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.
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Proteínas de Transporte de Catión , Proteínas de Unión al ADN , Regulación de la Expresión Génica , Yeyuno/metabolismo , Canales de Potasio con Entrada de Voltaje , Canales de Potasio/genética , Canales de Potasio/metabolismo , Transactivadores , Acetilcolina/farmacología , Empalme Alternativo , Secuencia de Aminoácidos , Secuencia de Bases , Benzopiranos/farmacología , Canales de Calcio/metabolismo , Relación Dosis-Respuesta a Droga , Canal de Potasio ERG1 , Canales de Potasio Éter-A-Go-Go , Humanos , Técnicas In Vitro , Potenciales de la Membrana/efectos de los fármacos , Contracción Muscular/efectos de los fármacos , Músculo Liso/metabolismo , Piperidinas/farmacología , Potasio/metabolismo , Cloruro de Potasio/farmacología , Piridinas/farmacología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Alineación de Secuencia , Factores de Tiempo , Regulador Transcripcional ERGRESUMEN
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.
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Transferasas Alquil y Aril/antagonistas & inhibidores , Antineoplásicos/química , Antineoplásicos/farmacología , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Imidazoles/química , Imidazoles/farmacología , Piperazinas/química , Piperazinas/farmacología , Animales , Relación Dosis-Respuesta a Droga , Diseño de Fármacos , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Concentración 50 Inhibidora , Ratones , Ratones Desnudos , Péptidos/química , Relación Estructura-Actividad , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
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.
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Transferasas Alquil y Aril/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Imidazoles/síntesis química , Pirroles/síntesis química , Diseño de Fármacos , Inhibidores Enzimáticos/química , Farnesiltransferasa , Imidazoles/farmacología , Concentración 50 Inhibidora , Pirroles/farmacología , Relación Estructura-ActividadAsunto(s)
Envejecimiento/genética , Colon/citología , Islas de CpG , Metilación de ADN , Proteínas de Homeodominio/genética , Proteína MioD/genética , Proteoglicanos/genética , Células Madre/citología , Factores de Transcripción/genética , Biglicano , Proteínas de la Matriz Extracelular , Proteína Homeótica Nkx-2.5 , Humanos , Modelos Biológicos , Modelos EstadísticosRESUMEN
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.
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Proteínas Quinasas Dependientes de GMP Cíclico/fisiología , Músculo Liso/fisiología , Óxido Nítrico/fisiología , Canales de Potasio de Dominio Poro en Tándem , Canales de Potasio/fisiología , Transmisión Sináptica/fisiología , Animales , Secuencia de Bases , Células COS , GMP Cíclico/farmacología , Cartilla de ADN , Ratones , Ratones Endogámicos BALB C , Músculo Liso/efectos de los fármacos , Músculo Liso/inervación , Mutagénesis Sitio-Dirigida , Nitroprusiato/farmacología , Técnicas de Placa-Clamp , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
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.
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Calcio/metabolismo , Colon/fisiología , Músculo Liso/fisiología , Canales de Potasio/metabolismo , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Células COS , Clonación Molecular , Perros , Humanos , Inmunohistoquímica , Ratones , Ratones Endogámicos BALB C , Datos de Secuencia Molecular , Técnicas de Placa-Clamp , Canales de Potasio/química , Canales de Potasio/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Alineación de Secuencia , Transmisión Sináptica/fisiología , Distribución TisularRESUMEN
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.
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Canales de Calcio Tipo L/fisiología , Colon/citología , Activación del Canal Iónico/fisiología , Músculo Liso/fisiología , Potenciales de Acción/efectos de los fármacos , Potenciales de Acción/fisiología , Animales , Bario/farmacología , Calcio/farmacocinética , Bloqueadores de los Canales de Calcio/farmacología , Canales de Calcio Tipo T/genética , Cesio/farmacología , Gadolinio/farmacología , Expresión Génica , Activación del Canal Iónico/efectos de los fármacos , Mibefradil/farmacología , Ratones , Ratones Endogámicos BALB C , Músculo Liso/citología , Músculo Liso/inervación , Inhibición Neural/fisiología , Nicardipino/farmacología , Níquel/farmacología , Técnicas de Placa-Clamp , Sodio/farmacología , TemperaturaRESUMEN
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.
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Dipéptidos/química , Imitación Molecular , Dipéptidos/síntesis química , Resonancia Magnética Nuclear Biomolecular , Estructura Secundaria de ProteínaRESUMEN
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%.
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Antibacterianos/farmacología , Enteritis/microbiología , Factores R , Salmonella/efectos de los fármacos , Humanos , Pruebas de Sensibilidad Microbiana , Salmonella/clasificación , Salmonella/aislamiento & purificaciónRESUMEN
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.
Asunto(s)
Éteres Cíclicos/síntesis química , Iminas/síntesis química , Fenilendiaminas/química , Éteres Cíclicos/química , Iminas/química , Modelos Moleculares , Conformación Molecular , Relación Estructura-Actividad , TermodinámicaRESUMEN
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.