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1.
Am J Transplant ; 19(1): 21-31, 2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-29956477

RESUMEN

The Lung session of the 2017 14th Banff Foundation for Allograft Pathology Conference, Barcelona focused on the multiple aspects of antibody-mediated rejection (AMR) in lung transplantation. Multidimensional approaches for AMR diagnosis, including classification, histological and immunohistochemical analysis, and donor- specific antibody (DSA) characterization with their current strengths and limitations were reviewed in view of recent research. The group also discussed the role of tissue gene expression analysis in the context of unmet needs in lung transplantation. The current best practice for monitoring of AMR and the therapeutic approach are summarized and highlighted in this report. The working group reached consensus of the major gaps in current knowledge and focused on the unanswered questions regarding pulmonary AMR. An important outcome of the meeting was agreement on the need for future collaborative research projects to address these gaps in the field of lung transplantation.


Asunto(s)
Anticuerpos/inmunología , Rechazo de Injerto/inmunología , Trasplante de Pulmón , Pulmón/inmunología , Aloinjertos , Complemento C4/inmunología , Perfilación de la Expresión Génica , Antígenos HLA/inmunología , Humanos , Inmunohistoquímica , Isoanticuerpos/inmunología , Fragmentos de Péptidos/inmunología , Sociedades Médicas , Donantes de Tejidos , Trasplante Homólogo
2.
Curr Oncol ; 24(2): 103-110, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28490924

RESUMEN

BACKGROUND: Although molecular testing has become standard in managing advanced nonsquamous non-small-cell lung cancer (nsclc), most patients undergo minimally invasive procedures, and the diagnostic tumour specimens available for testing are usually limited. A knowledge translation initiative to educate diagnostic specialists about sampling techniques and laboratory processes was undertaken to improve the uptake and application of molecular testing in advanced lung cancer. METHODS: A multidisciplinary panel of physician experts including pathologists, respirologists, interventional thoracic radiologists, thoracic surgeons, medical oncologists, and radiation oncologists developed a specialty-specific education program, adapting international clinical guidelines to the local Ontario context. Expert recommendations from the program are reported here. RESULTS: Panel experts agreed that specialists procuring samples for lung cancer diagnosis should choose biopsy techniques that maximize tumour cellularity, and that conservation strategies to maximize tissue for molecular testing should be used in tissue processing. The timeliness of molecular reporting can be improved by pathologist-initiated reflex testing upon confirmation of nonsquamous nsclc and by prompt transportation of specimens to designated molecular diagnostic centres. To coordinate timely molecular testing and optimal treatment, collaboration and communication between all clinicians involved in diagnosing patients with advanced lung cancer are mandatory. CONCLUSIONS: Knowledge transfer to diagnostic lung cancer specialists could potentially improve molecular testing and treatment for advanced lung cancer patients.

3.
Am J Transplant ; 16(4): 1229-37, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26730551

RESUMEN

Ex vivo lung perfusion (EVLP) is a platform to treat infected donor lungs with antibiotic therapy before lung transplantation. Human donor lungs that were rejected for transplantation because of clinical concern regarding infection were randomly assigned to two groups. In the antibiotic group (n = 8), lungs underwent EVLP for 12 h with high-dose antibiotics (ciprofloxacin 400 mg or azithromycin 500 mg, vancomycin 15 mg/kg, and meropenem 2 g). In the control group (n = 7), lungs underwent EVLP for 12 h without antibiotics. A quantitative decrease in bacterial counts in bronchoalveolar lavage (BAL) was found in all antibiotic-treated cases but in only two control cases. Perfusate endotoxin levels at 12 h were significantly lower in the antibiotic group compared with the control group. EVLP with broad-spectrum antibiotic therapy significantly improved pulmonary oxygenation and compliance and reduced pulmonary vascular resistance. Perfusate endotoxin levels at 12 h were strongly correlated with levels of perfusates tumor necrosis factor α, IL-1ß and macrophage inflammatory proteins 1α and 1ß at 12 h. In conclusion, EVLP treatment of infected donor lungs with broad-spectrum antibiotics significantly reduced BAL bacterial counts and endotoxin levels and improved donor lung function.


Asunto(s)
Antiinfecciosos/administración & dosificación , Trasplante de Pulmón/normas , Pulmón/microbiología , Perfusión/métodos , Obtención de Tejidos y Órganos/normas , Adulto , Antiinfecciosos/farmacología , Carga Bacteriana , Líquido del Lavado Bronquioalveolar/microbiología , Bronconeumonía/tratamiento farmacológico , Bronconeumonía/microbiología , Bronconeumonía/patología , Estudios de Casos y Controles , Circulación Extracorporea , Femenino , Estudios de Seguimiento , Humanos , Pulmón/efectos de los fármacos , Masculino , Persona de Mediana Edad , Pronóstico , Donantes de Tejidos
4.
Eur J Clin Microbiol Infect Dis ; 35(1): 67-74, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26492874

RESUMEN

Early eradication treatment with inhaled tobramycin is successful in the majority of children with cystic fibrosis (CF) with incident Pseudomonas aeruginosa infection. However, in 10-40 % of cases, eradication fails and the reasons for this are poorly understood. The purpose of this study was to determine whether specific microbial characteristics could explain eradication treatment failure. This was a cross-sectional study of CF patients (aged 0-18 years) with incident P. aeruginosa infection from 2011 to 2014 at the Hospital for Sick Children, Toronto, Canada. Phenotypic assays were done on all incident P. aeruginosa isolates, and eradicated and persistent isolates were compared using the Mann-Whitney test or the two-sided Chi-square test. A total of 46 children with CF had 51 incident P. aeruginosa infections. In 72 % (33/46) of the patients, eradication treatment was successful, while 28 % failed eradication therapy. Persistent isolates were less likely to be motile, with significantly less twitch motility (p=0.001), were more likely to be mucoid (p=0.002), and more likely to have a tobramycin minimum inhibitory concentration (MIC) ≥ 128 µg/mL (p=0.02) compared to eradicated isolates. Although biofilm production was similar, there was a trend towards more persistent isolates with deletions in quorum-sensing genes compared with eradicated isolates (p=0.06). Initial acquisition of P. aeruginosa with characteristics of chronic infection is associated with failure of eradication treatment.


Asunto(s)
Fibrosis Quística/complicaciones , Fenotipo , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/fisiología , Adolescente , Antibacterianos/uso terapéutico , Canadá , Niño , Preescolar , Estudios Transversales , Farmacorresistencia Bacteriana , Femenino , Eliminación de Gen , Humanos , Locomoción , Masculino , Pruebas de Sensibilidad Microbiana , Polisacáridos Bacterianos/metabolismo , Infecciones por Pseudomonas/tratamiento farmacológico , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/aislamiento & purificación , Pseudomonas aeruginosa/metabolismo , Percepción de Quorum , Tobramicina/uso terapéutico , Insuficiencia del Tratamiento
5.
Am J Transplant ; 13(6): 1586-93, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23601206

RESUMEN

The purpose of the study was to examine the effect of lentivirus-mediated IL-10 gene therapy to target lung allograft rejection in a mouse orthotopic left lung transplantation model. IL-10 may regulate posttransplant immunity mediated by IL-17. Lentivirus-mediated trans-airway luciferase gene transfer to the donor lung resulted in persistent luciferase activity up to 6 months posttransplant in the isograft (B6 to B6); luciferase activity decreased in minor-mismatched allograft lungs (B10 to B6) in association with moderate rejection. Fully MHC-mismatched allograft transplantation (BALB/c to B6) resulted in severe rejection and complete loss of luciferase activity. In minor-mismatched allografts, IL-10-encoding lentivirus gene therapy reduced the acute rejection score compared with the lentivirus-luciferase control at posttransplant day 28 (3.0 ± 0.6 vs. 2.0 ± 0.6 (mean ± SD); p = 0.025; n = 6/group). IL-10 gene therapy also significantly reduced gene expression of IL-17, IL-23, and retinoic acid-related orphan receptor (ROR)-γt without affecting levels of IL-12 and interferon-γ (IFN-γ). Cells expressing IL-17 were dramatically reduced in the allograft lung. In conclusion, lentivirus-mediated IL-10 gene therapy significantly reduced expression of IL-17 and other associated genes in the transplanted allograft lung and attenuated posttransplant immune responses after orthotopic lung transplantation.


Asunto(s)
Regulación hacia Abajo , Terapia Genética/métodos , Rechazo de Injerto/prevención & control , Interleucina-10/uso terapéutico , Interleucina-17/genética , Lentivirus/genética , Trasplante de Pulmón , Animales , Modelos Animales de Enfermedad , Femenino , Rechazo de Injerto/genética , Rechazo de Injerto/metabolismo , Supervivencia de Injerto/genética , Interleucina-10/genética , Interleucina-17/biosíntesis , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , ARN/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Trasplante Homólogo
6.
Curr Oncol ; 27(5): 244-249, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-33173375

RESUMEN

Background: Accurate classification of lung cancer subtypes has become critical in tailoring lung cancer treatment. Our study aimed to evaluate changes in diagnostic testing and pathologic subtyping of advanced non-small-cell lung cancer (nsclc) over time at a major cancer centre. Methods: In a review of patients diagnosed with advanced nsclc at Princess Margaret Cancer Centre between 2007-2009 and 2013-2015, diagnostic method, sample type and site, pathologic subtype, and use of immunohistochemistry (ihc) staining and molecular testing were abstracted. Results: The review identified 238 patients in 2007-2009 and 283 patients in 2013-2015. Over time, the proportion of patients diagnosed with adenocarcinoma increased to 73.1% from 60.9%, and diagnoses of nsclc not otherwise specified (nos) decreased to 6.4% from 18.9%, p < 0.0001. Use of diagnostic bronchoscopy decreased (26.9% vs. 18.4%), and mediastinal sampling procedures, including endobronchial ultrasonography, increased (9.2% vs. 20.5%, p = 0.0001). Use of ihc increased over time to 76.3% from 41.6% (p < 0.0001). Larger surgical or core biopsy samples and those for which ihc was performed were more likely to undergo biomarker testing (both p < 0.01). Conclusions: Customizing treatment based on pathologic subtype and molecular genotype has become key in treating patients with advanced lung cancer. Greater accuracy of pathology diagnosis is being achieved, including through the routine use of ihc.


Asunto(s)
Adenocarcinoma , Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma de Pulmón de Células no Pequeñas/diagnóstico , Carcinoma de Pulmón de Células no Pequeñas/genética , Femenino , Humanos , Inmunohistoquímica , Pulmón , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/genética , Masculino , Persona de Mediana Edad
7.
Science ; 251(5001): 1590-2, 1991 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-17793142

RESUMEN

An unusual distribution of particle sizes has been observed following the formation of molybdenum particles by argon ion sputtering. Many of the molybdenum particles produced by sputtering at the threshold pressure for particle formation in the vapor appear to be single crystalline cubes. There are two prominent peaks in the edge length distribution of the cubes, one centered at 4.8 nanometers with a halfwidth of approximately 1.3 nanometers and the other at 17.5 nanometers. The peak for the larger cubes is approximately square and has a total width of 7.0 nanometers. Evidence is presented that the larger cubes are formed by a 3 by 3 by 3 self-arrangement of the smaller cubes, which contain approximately 7000 atoms. Self-arrangement in inorganic structures is normally only observed when the building blocks are atoms, molecules, or clusters of less than 100 atoms.

8.
Science ; 247(4938): 57-9, 1990 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-17749491

RESUMEN

The defect structure of in situ pulsed, laser-deposited, thin films of the high-transition temperature superconductor Y-Ba-Cu-O has been observed directly by atomic resolution electron microscopy. In a thin film with the nominal composition YBa(2)Cu(3)O(7) (123), stacking defects corresponding to the cationic stoichiometry of the 248, 247, and 224 compounds have been observed. Other defects observed include edge dislocations and antiphase boundaries. These defects, which are related to the nonequilibrium processing conditions, are likely to be responsible for the higher critical currents observed in these films as compared to single crystals.

9.
Science ; 245(4916): 391-3, 1989 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-17744146

RESUMEN

Molecular beam epitaxy has been used to grow microcrystalline clusters of gallium arsenide (GaAs) in the size range from 2.5 to 60 nanometers on high-purity, amorphous silica supports. High-resolution transmission electron microscopy reveals that clusters as small as 3.5 nanometers have good crystalline order with a lattice constant equal to that of bulk GaAs. Study of the microcrystallite surfaces by x-ray photoelectron spectroscopy shows that they are covered with a shell (1.0 to 1.5 nanometers thick) of native oxides of gallium and arsenic (Ga(2)O(3) and As(2)O(3)), whose presence could explain the low luminescence efficiency of the clusters. Optical absorption spectra of the supported GaAs are consistent with the blue-shifted band edge expected for semiconductor microcrystallites in the quantum size regime.

10.
J Thorac Imaging ; 21(1): 50-3, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16538158

RESUMEN

Solitary fibrous tumor of the lung is a rare mesenchymal tumor entity that has been characterized histologically. Its CT features have not been described before in the radiologic literature. We present the clinical, radiologic, and imaging features of a solitary fibrous tumor of the lung. The lesion we describe demonstrated slow growth and well defined margins. Specifically, we demonstrate its avid heterogeneous enhancement following intravenous contrast administration. Although rare, the diagnosis should be considered in asymptomatic slow growing pulmonary nodules with similar features.


Asunto(s)
Neoplasias Pulmonares/diagnóstico , Neoplasias de Tejido Fibroso/diagnóstico , Nódulo Pulmonar Solitario/diagnóstico , Biopsia/métodos , Medios de Contraste/administración & dosificación , Diagnóstico Diferencial , Humanos , Pulmón/diagnóstico por imagen , Pulmón/patología , Pulmón/cirugía , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/cirugía , Masculino , Persona de Mediana Edad , Neoplasias de Tejido Fibroso/patología , Neoplasias de Tejido Fibroso/cirugía , Intensificación de Imagen Radiográfica/métodos , Enfermedades Raras , Nódulo Pulmonar Solitario/patología , Nódulo Pulmonar Solitario/cirugía , Tomografía Computarizada por Rayos X/métodos
11.
Biochim Biophys Acta ; 537(2): 284-92, 1978 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-31921

RESUMEN

Laser Raman spectra of cobrotoxin under various conditions have been obtained. Comparison of the spectra of native cobrotoxin in lyophilized form and in aqueous solution indicates that the secondary structures of cobrotoxin are not significantly affected by the removal of the aqueous solvent. On going from the native to the partially reduced and the completely reduced, carboxy-methylated forms, characteristic peaks of the C-S-S-C and tyrosine ring in the region of 500--900 cm-1 showed definite changes in structure. The partially reduced form gave two peaks at 502 and 524 cm-1, suggesting difference in the conformation of the remaining disulfide bonds. As indicated by the present work, the conformation of the main chain of cobrotoxin in the native unperturbed state, in the partially reduced and in the completely reduced forms are the coexistence of beta-pleated sheet with random-coil structure, predominantly random coil, and predominantly random coil with the existence of an alpha-helix type structure, respectively. The effect of pH on the conformation of cobrotoxin in solution appeared to give rise to the change of the local structure of two aromatic residues common to all snake neurotoxins.


Asunto(s)
Proteínas Neurotóxicas de Elápidos , Venenos Elapídicos , Animales , Disulfuros , Concentración de Iones de Hidrógeno , Oxidación-Reducción , Conformación Proteica , Especificidad de la Especie , Espectrometría Raman
12.
Biochim Biophys Acta ; 1305(3): 105-8, 1996 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-8597591

RESUMEN

During the large scale partial sequencing of human heart cDNA clones, a novel clone which is very similar to the rat ribosomal protein L29 in both DNA and amino acid sequences was found. The cDNA encodes a protein with a deduced molecular weight of 17751 (159 aa). It shows 80.4% homology to protein L29 from the large ribosomal subunit of rat and is related to yeast YL43. The putative protein was named human ribosomal protein L29 (hRPL29). hRPL29 has a large excess of basic residues over acidic ones. The large amount of charged residues makes the protein very hydrophilic and the protein has a deduced pI of 12.16. Internal repeats have been characterised in many ribosomal proteins and a tandem repeat of KAKAKAKA was found to be unique to hRPL29. Analysis of gene organisation by Southern blotting shows that of the approximate 10 copies of hrpL29, all but one are pseudogenes. Northern analysis indicated that the mRNA that encodes human L29 is approx. 800 base pairs in length. An intron of hrpL29 has also been cloned and sequenced by polymerase chain reaction using human genomic DNA as the template.


Asunto(s)
Proteínas Ribosómicas/biosíntesis , Proteínas Ribosómicas/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , ADN/aislamiento & purificación , Cartilla de ADN , ADN Complementario , Electroforesis en Gel de Agar , Humanos , Datos de Secuencia Molecular , Miocardio/metabolismo , Reacción en Cadena de la Polimerasa , Ratas , Secuencias Repetitivas de Ácidos Nucleicos , Proteínas Ribosómicas/química , Homología de Secuencia de Aminoácido
13.
J Clin Pathol ; 63(1): 38-46, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19858531

RESUMEN

With increasing numbers of lung transplants being performed worldwide, lung transplant allograft biopsies are becoming increasingly common. The evaluation of lung transplant biopsies typically focuses on the assessment of allograft rejection and infection, but other entities may also be seen in biopsy material. Presented here is an approach to lung transplant biopsies, in which there is an overview major diagnostic entities that may be encountered and discussion of findings that may present interpretive challenges.


Asunto(s)
Trasplante de Pulmón/patología , Pulmón/patología , Enfermedad Aguda , Biopsia/métodos , Bronquitis/patología , Enfermedad Crónica , Rechazo de Injerto/inmunología , Rechazo de Injerto/patología , Humanos , Trastornos Linfoproliferativos/patología , Complicaciones Posoperatorias/patología , Infecciones del Sistema Respiratorio/patología
14.
Can Respir J ; 17(3): e42-4, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20617213

RESUMEN

Primary or nonobstructive, endogenous lipoid pneumonia is a rare clinical entity usually associated with an underlying systemic disease. The present report describes a case involving a 21-year-old man with systemic-onset juvenile rheumatoid arthritis who developed primary endogenous lipoid pneumonia. Multiple treatment regimens were attempted; however, definitive management was only achieved through double-lung transplantation.


Asunto(s)
Artritis Juvenil/complicaciones , Neumonía/diagnóstico , Tos/etiología , Disnea/etiología , Humanos , Trasplante de Pulmón , Masculino , Neumonía/etiología , Neumonía/cirugía , Adulto Joven
15.
Br J Radiol ; 80(956): e162-6, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17762047

RESUMEN

Lymphomatoid granulomatosis is a rare lymphoproliferative disorder which affects extranodal sites, most commonly lung. Radiologically, it typically presents with multiple nodular opacities that may wax and wane. The reversed halo sign has previously been reported in cryptogenic organizing pneumonia and more recently in South American blastomycosis. We describe a case of histologically proven lymphomatoid granulomatosis in a patient who presented initially with the more typical nodular opacities, which subsequently progressed into the reversed halo sign. To the best of our knowledge, this association has not been previously described.


Asunto(s)
Enfermedades Pulmonares/diagnóstico por imagen , Granulomatosis Linfomatoide/diagnóstico por imagen , Femenino , Humanos , Persona de Mediana Edad , Tomografía Computarizada por Rayos X/métodos
16.
J Mol Cell Cardiol ; 26(10): 1329-33, 1994 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-7869393

RESUMEN

A human fetal heart cDNA library was constructed in the lambda gt22A expression vector. Polymerase chain reaction (PCR) was used to amplify the cDNA inserts. PCR products were purified and used in cycle sequencing reactions in the presence of a fluorescein-conjugated primer and electrophoresed on a Pharmacia A.L.F. Sequencer. Partial cDNA sequences, or expressed sequence tags (ESTs) were searched against the Genbank and EMBL databases to identify novel genes expressed in the human cardiovascular system.


Asunto(s)
Sistema Cardiovascular/metabolismo , ADN Complementario/genética , Corazón Fetal/química , Biblioteca de Genes , Genes , Análisis de Secuencia de ADN , Secuencia de Bases , Expresión Génica , Humanos , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Homología de Secuencia de Ácido Nucleico
17.
Taiwan Yi Xue Hui Za Zhi ; 88(5): 517-9, 1989 May.
Artículo en Inglés | MEDLINE | ID: mdl-2794953

RESUMEN

Non-traumatic colon perforations are usually caused by malignancy, diverticulum and colitis. They rarely result from stool impaction. A 74-year-old woman with stercoracous perforation of the colon is reported. She had a long history of constipation and hypertension treated irregularly with cathartics, enemas, diuretics and beta-blockers. Resection of the perforated colon with a proximal diverting colostomy and Hartman's procedure was performed. The patient tolerated the operation and subsequent reanastomosis 6 weeks later. In the case of elderly patients with constipation, early management of the constipation is mandatory, although this condition of stercoraceous perforation is rare.


Asunto(s)
Enfermedades del Colon/etiología , Impactación Fecal/complicaciones , Perforación Intestinal/etiología , Anciano , Enfermedades del Colon/patología , Femenino , Humanos , Perforación Intestinal/patología
18.
Gaoxiong Yi Xue Ke Xue Za Zhi ; 5(6): 309-13, 1989 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-2778865

RESUMEN

The management of obstructing left-sided colon cancer remains controversial. The advent of intraoperative antegrade colonic irrigation (I.A.C.I.) has allowed primary anastomosis to be performed in the obstructed bowel. From July 1985 to Feb. 1989, there were eleven patients with obstructing left-sided colon cancer admitted to Changhwa Christian Hospital. Eight of these patients, five men and three women, age ranged from 31 to 80 years old, accepted the I.A.C.I. procedure and followed by the one-staged operations. The I.A.C.I. procedure was advocated by Dudley et al in 1980. Postoperatively, there was no case which suffered from clinical leakage or sepsis, except two cases with mild wound infection. Consequently, there was no operative mortality.


Asunto(s)
Neoplasias del Colon/cirugía , Obstrucción Intestinal/cirugía , Adulto , Anciano , Femenino , Humanos , Cuidados Intraoperatorios , Masculino , Persona de Mediana Edad , Irrigación Terapéutica
19.
J Biol Chem ; 266(27): 17919-25, 1991 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-1717444

RESUMEN

Cys-cdc2(8-20), a synthetic peptide derived from p34cdc2, was previously reported to be a specific and efficient substrate of a pp60c-src-related tyrosine kinase isolated from bovine spleen (the spleen tyrosine kinase) (Litwin, C.M.E., Cheng, H.-C., and Wang, J.H. (1991) J. Biol. Chem. 266, 2557-2566). The longer peptide, cdc2(1-24), was found to be phosphorylated by the kinase with similar efficiency, and Tyr15 was the only amino acid residue phosphorylated. This indicated that the amino acid sequence of cdc2(8-20) peptide, EKI-GEGTYGVVYK, contained the structural features important for protein tyrosine kinase substrate activity. A stepwise procedure using synthetic peptides was employed to investigate such structural features. First, a computer search of protein sequences homologous to cdc2(8-20) uncovered five protein kinases containing homologous sequence with tyrosine at a position corresponding to Tyr15 of p34cdc2. Second, a peptide derived from ribosomal S6 protein kinase (rsk(436-456] was synthesized. The rsk(436-456) peptide contained a segment, ETIGVGSYSVCKR, which is highly homologous to that of cdc2(8-20). It was found to be a very poor substrate of the spleen tyrosine kinase. Third, peptide analogs of cdc2(6-20) with single substitutions of amino acid residues Lys9, Glu12, Thr14, Gly16, Val18, and Tyr19 by amino acid residues at corresponding positions of rsk were synthesized and tested as spleen tyrosine kinase substrates. Only Glu12 and Thr14 substituted peptide analogs showed decreased substrate activities. (The substrate activity of a peptide is the ability of the peptide to serve as the substrate of the spleen tyrosine kinase. It was determined of the spleen tyrosine kinase. It was determined either by the kinetic parameters (Km and Vmax) of phosphorylation of the peptide or by the initial phosphorylation rate of the peptide by the spleen tyrosine kinase.) An analog with double substitution at Glu12 An analog with double substitution at Glu12 and Thr14 was found to be almost as poor a substrate as the rsk peptide. In addition, peptide analogs with Tyr15 substituted by Phe or D-Tyr had poor substrate activities as well as weak inhibitory activities. Thus, Glu12, Thr14, and Tyr15 residues of p34cdc2 contained structural components essential for the efficient phosphorylation of the peptides derived from p34cdc2 by the pp60c-src-related spleen tyrosine kinase.


Asunto(s)
Proteína Quinasa CDC2/metabolismo , Proteínas Tirosina Quinasas/metabolismo , Proteínas Proto-Oncogénicas pp60(c-src)/metabolismo , Secuencia de Aminoácidos , Animales , Proteína Quinasa CDC2/análogos & derivados , Proteína Quinasa CDC2/síntesis química , Bovinos , Cromatografía Líquida de Alta Presión , Cinética , Datos de Secuencia Molecular , Fragmentos de Péptidos/síntesis química , Fragmentos de Péptidos/metabolismo , Fosforilación , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Bazo/enzimología
20.
J Mol Cell Cardiol ; 29(1): 281-7, 1997 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9040043

RESUMEN

The Zn2+-finger DNA-binding domain has been identified in several developmental control proteins, transcription factors and gene products associated with diseases, as well as in several RNA-binding proteins. We applied library screening, expressed sequence tagging (EST sequencing), Zn2+-binding assays and Northern blot hybridization, in order to characterize novel cDNA clones of the human cardiovascular system which contain Zn2+-finger motifs. An embryonic (8-10 weeks gestation) heart lambda ZAP Express cDNA library was screened with an oligonucleotide probe deduced from a consensus amino acid sequence which is highly conserved for Zn2+-finger proteins, and approximately 350 positive clones were isolated from 1 x 10(4) plaque-forming units (pfu) initially plated. The isolated clones were classified as known and novel following single pass automated DNA sequencing. Analysis of Northern blot hybridization delineated the tissue specificity of these clones, as well as their association with cardiac growth and development. Existence of Zn2+-finger motifs in the novel clones was confirmed by Zn2+-binding assay. In this report, we present the characterization of eight novel clones, including the complete cDNA sequences of one of these clones (HHZ-123).


Asunto(s)
Fenómenos Fisiológicos Cardiovasculares , ADN Complementario/genética , Biblioteca de Genes , Dedos de Zinc/genética , Secuencia de Aminoácidos , Secuencia de Bases , Mapeo Cromosómico , Clonación Molecular , Código Genético , Humanos , Datos de Secuencia Molecular , Sondas de Oligonucleótidos
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