RESUMEN
Essentials Reduction of three disulfide bonds in factor (F) XI enhances chromogenic substrate cleavage. We measured FXI activity upon reduction and identified a bond involved in the enhanced activity. Reduction of FXI augments FIX cleavage, probably by faster conversion of FXI to FXIa. The Cys362-Cys482 disulfide bond is responsible for FXI enhanced activation upon its reduction. SUMMARY: Background Reduction of factor (F) XI by protein disulfide isomerase (PDI) has been shown to enhance the ability of FXI to cleave its chromogenic substrate. Three disulfide bonds in FXI (Cys118-Cys147, Cys362-Cys482, and Cys321-Cys321) are involved in this augmented activation. Objectives To characterize the mechanisms by which PDI enhances FXI activity. Methods FXI activity was measured following PDI reduction. Thiols that were exposed in FXI after PDI reduction were labeled with 3-(N-maleimidopropionyl)-biocytin (MPB) and detected with avidin. The rate of conversion of FXI to activated FXI (FXIa) following thrombin activation was assessed with western blotting. FXI molecules harboring mutations that disrupt the three disulfide bonds (C147S, C321S, and C482S) were expressed in cells. The antigenicity of secreted FXI was measured with ELISA, and its activity was assessed by the use of a chromogenic substrate. The effect of disulfide bond reduction was analyzed by the use of molecular dynamics. Results Reduction of FXI by PDI enhanced cleavage of both its chromogenic substrate, S2366, and its physiologic substrate, FIX, and resulted in opening of the Cys362-Cys482 bond. The rate of conversion of FXI to FXIa was increased following its reduction by PDI. C482S-FXI showed enhanced activity as compared with both wild-type FXI and C321S-FXI. MD showed that disruption of the Cys362-Cys482 bond leads to a broader thrombin-binding site in FXI. Conclusions Reduction of FXI by PDI enhances its ability to cleave FIX, probably by causing faster conversion of FXI to FXIa. The Cys362-Cys482 disulfide bond is involved in enhancing FXI activation following its reduction, possibly by increasing thrombin accessibility to FXI.
Asunto(s)
Factor XI/química , Proteína Disulfuro Isomerasas/química , Sitio Alostérico , Animales , Avidina/química , Sitios de Unión , Coagulación Sanguínea , Coagulantes/química , Cricetinae , Cisteína/química , Disulfuros/química , Factor IX/química , Humanos , Lisina/análogos & derivados , Lisina/química , Simulación de Dinámica Molecular , Mutación , Pliegue de Proteína , Trombina/químicaRESUMEN
Unexpectedly, a post-translational modification of DNA-binding proteins, initiating the cell response to single-strand DNA damage, was also required for long-term memory acquisition in a variety of learning paradigms. Our findings disclose a molecular mechanism based on PARP1-Erk synergism, which may underlie this phenomenon. A stimulation induced PARP1 binding to phosphorylated Erk2 in the chromatin of cerebral neurons caused Erk-induced PARP1 activation, rendering transcription factors and promoters of immediate early genes (IEG) accessible to PARP1-bound phosphorylated Erk2. Thus, Erk-induced PARP1 activation mediated IEG expression implicated in long-term memory. PARP1 inhibition, silencing, or genetic deletion abrogated stimulation-induced Erk-recruitment to IEG promoters, gene expression and LTP generation in hippocampal CA3-CA1-connections. Moreover, a predominant binding of PARP1 to single-strand DNA breaks, occluding its Erk binding sites, suppressed IEG expression and prevented the generation of LTP. These findings outline a PARP1-dependent mechanism required for LTP generation, which may be implicated in long-term memory acquisition and in its deterioration in senescence.
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Región CA1 Hipocampal/fisiología , Región CA3 Hipocampal/fisiología , Regulación de la Expresión Génica , Potenciación a Largo Plazo , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Poli(ADP-Ribosa) Polimerasa-1/metabolismo , Animales , Ratones , Ratones Noqueados , Unión ProteicaRESUMEN
Activity-dependent neuroprotective protein (ADNP), essential for brain formation, is a frequent autism spectrum disorder (ASD)-mutated gene. ADNP associates with microtubule end-binding proteins (EBs) through its SxIP motif, to regulate dendritic spine formation and brain plasticity. Here, we reveal SKIP, a novel four-amino-acid peptide representing an EB-binding site, as a replacement therapy in an outbred Adnp-deficient mouse model. We discovered, for the first time, axonal transport deficits in Adnp(+/-) mice (measured by manganese-enhanced magnetic resonance imaging), with significant male-female differences. RNA sequencing evaluations showed major age, sex and genotype differences. Function enrichment and focus on major gene expression changes further implicated channel/transporter function and the cytoskeleton. In particular, a significant maturation change (1 month-five months) was observed in beta1 tubulin (Tubb1) mRNA, only in Adnp(+/+) males, and sex-dependent increase in calcium channel mRNA (Cacna1e) in Adnp(+/+) males compared with females. At the protein level, the Adnp(+/-) mice exhibited impaired hippocampal expression of the calcium channel (voltage-dependent calcium channel, Cacnb1) as well as other key ASD-linked genes including the serotonin transporter (Slc6a4), and the autophagy regulator, BECN1 (Beclin1), in a sex-dependent manner. Intranasal SKIP treatment normalized social memory in 8- to 9-month-old Adnp(+/-)-treated mice to placebo-control levels, while protecting axonal transport and ameliorating changes in ASD-like gene expression. The control, all d-amino analog D-SKIP, did not mimic SKIP activity. SKIP presents a novel prototype for potential ASD drug development, a prevalent unmet medical need.
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Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Microtúbulos/fisiología , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Secuencias de Aminoácidos , Animales , Trastorno del Espectro Autista/etiología , Trastorno del Espectro Autista/genética , Transporte Axonal/genética , Transporte Axonal/fisiología , Encéfalo/metabolismo , Canales de Calcio/metabolismo , Canales de Calcio Tipo R/genética , Canales de Calcio Tipo R/metabolismo , Proteínas de Transporte de Catión/genética , Proteínas de Transporte de Catión/metabolismo , Espinas Dendríticas/metabolismo , Femenino , Hipocampo/metabolismo , Masculino , Memoria , Ratones , Microtúbulos/metabolismo , ARN Mensajero/metabolismo , Factores Sexuales , Tubulina (Proteína)/metabolismo , Moduladores de Tubulina/metabolismoRESUMEN
Hypotrichosis with juvenile macular dystrophy (HJMD) and ectodermal dysplasia, ectrodactyly and macular dystrophy (EEM) are both caused by mutations in the CDH3 gene. In this report, we describe a family with EEM syndrome caused by a novel CDH3 gene mutation and review the mutation spectrum and limb abnormalities in both EEM and HJMD. A protein structure model showing the localization of different mutations causing both syndromes is presented. The CDH3 gene was sequenced and investigation of the mutations performed using a protein structure model. The conservation score was calculated by ConSurf. We identified a novel CDH3 gene mutation, p.G277V, which resides in a conserved residue located on a ß-strand in the second cadherin domain. Review of the data on previously published mutations showed intra-familial and inter-familial variations in the severity of the limb abnormalities. Syndactyly was the most consistent clinical finding present in all the patients regardless of mutation type. The results of our study point to a phenotypic continuum between HJMD and EEM. It is important for genetic counseling to keep in mind the possible clinical/phenotypic overlap between these 2 syndromes and to be aware of the possible risk of limb abnormalities in future pregnancies in families with HJMD syndrome. CDH3 gene mutation screening is recommended in patients with both these syndromes as part of the work-up in order to offer appropriate genetic counseling.
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In 1988 the Department of Family Medicine at Ben Gurion University of the Negev in Israel developed a course that helps residents to acquire the attitudes and skills required for practicing patient-centered medicine. In the patient-centered approach, the physician relates to patients according to their needs rather than the doctor's own agenda, moving from professional control to patient empowerment. Though there are many elements to this method, certain basic orientations and skills are essential and must be taught, modeled, and reinforced in trainees. To accomplish these aims, a three-year course was developed, which is largely based on directed reading, open discussion, case presentations, role-plays, and Balint groups. It is composed of four levels, each of which must be mastered before residents can move to the next. The levels are (1) doctor-patient communication; (2) family-systems theory-concepts; (3) family-systems theory-practical applications; and (4) multidimensional approaches to simulated patients. In this article, the authors describe the course's concepts and content, and some indicators as to its influence on graduates.
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Curriculum , Medicina Familiar y Comunitaria/educación , Internado y Residencia , Atención Dirigida al Paciente , Humanos , Simulación de Paciente , Relaciones Profesional-Familia , Estados UnidosRESUMEN
BACKGROUND: The study presents the advantages of the psychiatric liaison-attachment scheme, by analyzing the psychiatric consultations of a 12 months period (1995), in an urban family medicine clinic in Israel. METHOD: Family physicians filled a questionnaire about all patients who had been seen at the consultation. RESULTS: The consulting psychiatrist saw 46 patients. The reasons for consultation were mostly to confirm a diagnosis and to decide upon medications. Medical diagnoses most often made were depression and personality disorder. The psychiatrist referred 35% of patients for further therapy in the psychiatric clinic. The family physicians would have referred 45% of patients to psychiatric clinics, if they had no psychiatric consultation available. All patients referred complied with the recommended referral. Family physicians saw accessibility as the main advantage of this consultation strategy. LIMITATIONS: This study was done in a unique setting, a teaching family medicine clinic, with nine specialized family physicians working in the psychiatric liaison-attachment scheme for as long as 10 years and more. Therefore the results of this study may not be generalized to other clinics. CONCLUSIONS: We conclude that the advantages of the psychiatric liaison-consultation method were for the patients, the family physicians and the psychiatric consultant. The main advantages for the family physicians, as stated by them, were the accessibility, the non-stigmatic availability of a psychiatrist in the clinic, and the good compliance with referral to psychiatric therapy. For the consulting psychiatrist, the advantages were the valuable information from the family physicians and the social worker, the better follow-up of patients and the team work with the family practice team.
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Atención Primaria de Salud , Psiquiatría , Derivación y Consulta , Adulto , Femenino , Humanos , Israel , Masculino , Trastornos Mentales/diagnósticoRESUMEN
The present study seeks to show the influence of biographical experiences of Holocaust survivors on the sense of coherence (SOC), in Antonovsky's theory, a construct which has been shown to be linked to health status. It was postulated that three central biographical issues--(1) the existence of an intimate environment; (2) the fulfillment of developmental tasks; and (3) engagement in a meaningful major activity--would be related to the survivor's present SOC. A structured interview was designed to cover different experiences of the survivors, focusing on these three issues at five age periods (6, 15, 24 and 45), in World War II and at present. Interviews were conducted with 20 elderly survivors born between 1920 to 1925. Quality of experience biographical scores at each age and in each of the three areas were assessed. Respondents also completed the SOC scale independently. A high correlation between the overall "Biography" score and the SOC was found. "Meaningful major activity" seems to play a more significant role in the subsequent development of a strong SOC than do the other two life issues. No significant correlations between any of the five specific ages and the SOC were found.
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Adaptación Psicológica , Holocausto/psicología , Judíos , Medio Social , Sobrevida/psicología , Anciano , Femenino , Humanos , Relaciones Interpersonales , Entrevistas como Asunto , Masculino , Memoria , Modelos Psicológicos , Diferencial Semántico , Encuestas y Cuestionarios , Grabación en CintaRESUMEN
We describe the process of planning and developing a questionnaire and conducting a patient satisfaction survey in a neighbourhood clinic in Beer-Sheva, Israel. The project was conducted by the clinic staff members, patient representatives and a medical sociologist. The satisfaction survey was conducted in patients' homes, with a 67% response rate. General satisfaction and satisfaction with specific components of service are described. Patient satisfaction was higher among men than among women, and negatively correlated with family size. The strongest predictor of general satisfaction was satisfaction with physicians' services. Implications of the survey results were decided upon by active collaboration between the clinic staff and the patient representatives. The inferences drawn from the patients' replies and the changes introduced as a result of them, are discussed. Health care consumers should be active participants in carrying out surveys of satisfaction on a regular basis.
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Grupo de Atención al Paciente , Satisfacción del Paciente , Atención Primaria de Salud , Adolescente , Adulto , Anciano , Centros Comunitarios de Salud , Participación de la Comunidad , Femenino , Humanos , Israel , Masculino , Persona de Mediana Edad , Garantía de la Calidad de Atención de Salud , Ciencias SocialesRESUMEN
Normal human serum effectively inhibits a bioassay for erythropoietin based on DNA synthesis by rabbit erythroid precursors. This heat-sensitive inhibitory activity is readily lost on dilution of serum, revealing the presence of erythropoietin-potentiating activity. Inhibitory activity is caused by a rapid cytotoxic effect on rabbit bone marrow cells; mouse cells are less sensitive. Cytotoxic activity is removed from serum by adsorption to protein A, is not expressed at 4 degrees C, and is neutralized by anti-C3c complement antibody. Cytotoxicity is inhibited by EGTA; the effect of EGTA is reversed by addition of Ca2+ ions. These findings show that cytotoxicity is exerted through an antibody via the classical pathway of complement-dependent cell lysis. Although serum from healthy, adult human donors consistently contains cytotoxic activity, no such activity is observed in most serum samples from neonates, parturients, and patients with severe anemia. Patients with polycythemia or chronic renal failure occasionally lack cytotoxic activity in their serum. Serum samples lacking cytotoxic activity were found to be deficient in the antibody component in 34 out of 35 cases examined. These results show that an antibody directed against rabbit cells is constitutively present in normal human serum but is absent in a number of pathologic situations as well as being absent in neonates and parturients.