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1.
Radiologia (Engl Ed) ; 64(5): 407-414, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36243440

RESUMO

BACKGROUND: The brainstem, situated in the posterior fossa, connects the brain to the spinal cord. Owing to its location, the nerves of the brainstem are closely related with vascular structures. OBJECTIVES: To correlate the finding of vascular loops in the cerebellopontine angle on imaging with symptoms indicative of vestibulocochlear involvement. MATERIALS AND METHODS: This retrospective descriptive study included all patients evaluated between 2011 and 2017 with findings suggestive of vascular loops in the cerebellopontine angle for whom the clinical history and imaging studies were available. RESULTS: A total of 102 patients (63 women and 39 men) had vestibulocochlear involvement. The most common clinical indication was dizziness (41.18%). A unilateral vascular loop was found in 43 patients (right: 21.57%, left: 20.59%) and bilateral loops were found in 59 (57.84%) patients. The most common type of vascular loop was type II (right: 69.14%; left: 58.75%). The most common origin of vascular loops was the anterior inferior cerebellar artery (right: 66.67%, left: 65.00%). No associations were observed between vascular loops and sensorineural hearing, nystagmus, or vertigo. There was an association with tinnitus. CONCLUSIONS AND SIGNIFICANCE: The presence of vascular loops is not associated with most auditory symptoms. Nevertheless, all findings on imaging studies must be reported. The interpretation of the findings of imaging studies must be correlated with the clinical symptoms after other more common causes that can explain the symptoms have been ruled out.


Assuntos
Ângulo Cerebelopontino , Zumbido , Artéria Basilar , Ângulo Cerebelopontino/irrigação sanguínea , Ângulo Cerebelopontino/diagnóstico por imagem , Feminino , Humanos , Masculino , Estudos Retrospectivos , Zumbido/diagnóstico por imagem , Zumbido/etiologia
2.
Radiología (Madr., Ed. impr.) ; 64(5): 407-414, Sep.-Oct. 2022. ilus, tab
Artigo em Espanhol | IBECS | ID: ibc-209916

RESUMO

Antecedentes: El tronco encefálico, situado en la fosa posterior, conecta el cerebro con la médula espinal. Debido a su ubicación, sus componentes nerviosos guardan una estrecha relación con estructuras vasculares. Objetivos: Describir una relación clínico-radiológica del asa vascular del ángulo pontocerebeloso en pacientes con síntomas indicativos de afectación vestibulococlear mediante evaluación por neuroimagen. Materiales y métodos: Se realizó un estudio retrospectivo y descriptivo. Se incluyeron todos los pacientes evaluados entre 2011 y 2017 con indicios de asa vascular del ángulo pontocerebeloso e historial clínico y estudios de diagnóstico por imagen disponibles. Resultados: 102 pacientes (63 mujeres y 39 hombres) presentaban afectación vestibulococlear. La indicación clínica más frecuente fue mareos (41,18%). Se halló asa vascular unilateral en 43 pacientes (derecho: 21,57%, izquierdo: 20,59%) y bilateral en 59 pacientes (57,84%). El tipo de asa vascular más frecuente fue el tipo II (derecho: 69,14%; izquierdo: 58,75%). El origen más frecuente fue la arteria cerebelosa anteroinferior (ACAI) (derecha: 66,67%, izquierda: 65,00%). No se observó ninguna asociación entre asas vasculares y pérdida de audición neurosensitiva, nistagmo o vértigo. Se halló una asociación con acúfenos. Conclusiones y significación: La presencia de asas vasculares no se asocia a la mayoría de los síntomas auditivos. No obstante, deben notificarse todos los hallazgos de los estudios por imagen. La interpretación de los hallazgos de los estudios por imagen debe correlacionarse con los síntomas clínicos después de excluir otras causas más frecuentes que puedan explicar la sintomatología.(AU)


Background: The brainstem, situated in the posterior fossa, connects the brain to the spinal cord. Owing to its location, the nerves of the brainstem are closely related with vascular structures. Objectives: To correlate the finding of vascular loops in the cerebellopontine angle on imaging with symptoms indicative of vestibulocochlear involvement. Materials and methods: This retrospective descriptive study included all patients evaluated between 2011 and 2017 with findings suggestive of vascular loops in the cerebellopontine angle for whom the clinical history and imaging studies were available. Results: A total of 102 patients (63 women and 39 men) had vestibulocochlear involvement. The most common clinical indication was dizziness (41.18%). A unilateral vascular loop was found in 43 patients (right: 21.57%, left: 20.59%) and bilateral loops were found in 59 (57.84%) patients. The most common type of vascular loop was type II (right: 69.14%; left: 58.75%). The most common origin of vascular loops was the anterior inferior cerebellar artery (right: 66.67%, left: 65.00%). No associations were observed between vascular loops and sensorineural hearing, nystagmus, or vertigo. There was an association with tinnitus. Conclusions and significance: The presence of vascular loops is not associated with most auditory symptoms. Nevertheless, all findings on imaging studies must be reported. The interpretation of the findings of imaging studies must be correlated with the clinical symptoms after other more common causes that can explain the symptoms have been ruled out.(AU)


Assuntos
Humanos , Masculino , Feminino , Ângulo Cerebelopontino , Tronco Encefálico , Neuroimagem , Correlação de Dados , Nervo Vestibulococlear , Transtornos Cerebrovasculares , Imageamento por Ressonância Magnética , Doenças do Nervo Vestibulococlear , Estudos Retrospectivos , Epidemiologia Descritiva , Radiologia , Diagnóstico por Imagem
3.
Radiologia (Engl Ed) ; 2020 Oct 08.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-33041072

RESUMO

BACKGROUND: The brainstem, situated in the posterior fossa, connects the brain to the spinal cord. Owing to its location, the nerves of the brainstem are closely related with vascular structures. OBJECTIVES: To correlate the finding of vascular loops in the cerebellopontine angle on imaging with symptoms indicative of vestibulocochlear involvement. MATERIALS AND METHODS: This retrospective descriptive study included all patients evaluated between 2011 and 2017 with findings suggestive of vascular loops in the cerebellopontine angle for whom the clinical history and imaging studies were available. RESULTS: A total of 102 patients (63 women and 39 men) had vestibulocochlear involvement. The most common clinical indication was dizziness (41.18%). A unilateral vascular loop was found in 43 patients (right: 21.57%, left: 20.59%) and bilateral loops were found in 59 (57.84%) patients. The most common type of vascular loop was type II (right: 69.14%; left: 58.75%). The most common origin of vascular loops was the anterior inferior cerebellar artery (right: 66.67%, left: 65.00%). No associations were observed between vascular loops and sensorineural hearing, nystagmus, or vertigo. There was an association with tinnitus. CONCLUSIONS AND SIGNIFICANCE: The presence of vascular loops is not associated with most auditory symptoms. Nevertheless, all findings on imaging studies must be reported. The interpretation of the findings of imaging studies must be correlated with the clinical symptoms after other more common causes that can explain the symptoms have been ruled out.

4.
An Pediatr (Barc) ; 77(6): 360-5, 2012 Dec.
Artigo em Espanhol | MEDLINE | ID: mdl-22119727

RESUMO

INTRODUCTION: Non-compaction of the ventricular myocardium (NCVM) is a rare congenital heart disease. Heightened awareness has resulted in increased detection of the morphological features of NCVM in routine clinical practice. PATIENTS AND METHODS: Multicentre study including paediatric patients affected by NCVM according to the echocardiographic criteria of Chin and Jenni. RESULTS: A total of 29 patients were included, 15 female and 14 male, the median age at diagnosis was 5 years and 7 months (birth to 17 years). Sixteen patients (55%) presented as an isolated lesion, 8 (27.5%) had a ventricular septal defect, one of them associated with aortic coarctation, 3 (10%) had an inborn error of metabolism, 1 (3.5%) had Juvenile Idiopathic Arthritis and 1 (3.5%) has a syndrome being studied. The location of the trabeculae has been predominantly at the apex, but also affected the left ventricle free wall in 11 patients (40%) and right ventricle in 2 (7%). No complications were present in 12 patients (41%), with cardiac failure in 12 patients (41%), an implantable cardioverter defibrillator was placed for ventricular arrhythmias in 2 patients (7%), stroke, 1 patient (3,5%) and death, 2 patients (7%), both of them less than 6 months of age (P<.05). Median follow up was 12 months (2 months to 8 years). Current treatment includes carvedilol, ACEI's and ASA, and one patient is waiting for a cardiac transplantation. CONCLUSIONS: Early onset of symptoms is associated with a poor prognosis. Clinical and prognostic heterogeneity is described.


Assuntos
Miocárdio Ventricular não Compactado Isolado/diagnóstico , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Prognóstico
7.
Foot Ankle Int ; 22(10): 775-8, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11642528

RESUMO

The use of retrospectively acquired preoperative AOFAS rating scores in clinical research to assess the outcomes of elective foot and ankle surgery has not been validated. The data obtained utilizing this methodology may misrepresent the results and lead to spurious conclusions. This investigation compared preoperative AOFAS Ankle-Hindfoot scores obtained before and after surgery from patients who had undergone elective surgery to determine if retrospectively acquired scores match those collected prospectively. Only two out of 47 patients (4%) recalled identical AOFAS scores. The mean difference between the preoperative scores (preoperative score obtained after surgery minus preoperative score obtained before surgery) was -5.3 points. Fifteen patients (32%) had preoperative scores that differed by 20 points or more. Kappa statistics found little agreement among the five elements that comprised the two preoperative scores when responses obtained before and after surgery were compared to one another. The results suggest that preoperative clinical rating scores obtained after elective surgery are a poor predictor of the patient's preoperative condition and that studies which employ retrospectively acquired preoperative AOFAS clinical rating scores may overestimate the benefit of surgery.


Assuntos
Tornozelo/cirurgia , Pé/cirurgia , Ortopedia , Avaliação de Resultados em Cuidados de Saúde , Sociedades Médicas , Adulto , Interpretação Estatística de Dados , Humanos , Satisfação do Paciente , Pesquisa , Estados Unidos , Caminhada
8.
J Lipid Res ; 42(2): 170-80, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11181745

RESUMO

The scavenger receptor class B type I (SR-BI), which is expressed in the liver and intestine, plays a critical role in cholesterol metabolism in rodents. While hepatic SR-BI expression controls high density lipoprotein (HDL) cholesterol metabolism, intestinal SR-BI has been proposed to facilitate cholesterol absorption. To evaluate further the relevance of SR-BI in the enterohepatic circulation of cholesterol and bile salts, we studied biliary lipid secretion, hepatic sterol content and synthesis, bile acid metabolism, fecal neutral sterol excretion, and intestinal cholesterol absorption in SR-BI knockout mice. SR-BI deficiency selectively impaired biliary cholesterol secretion, without concomitant changes in either biliary bile acid or phospholipid secretion. Hepatic total and unesterified cholesterol contents were slightly increased in SR-BI-deficient mice, while sterol synthesis was not significantly changed. Bile acid pool size and composition, as well as fecal bile acid excretion, were not altered in SR-BI knockout mice. Intestinal cholesterol absorption was somewhat increased and fecal sterol excretion was slightly decreased in SR-BI knockout mice relative to controls. These findings establish the critical role of hepatic SR-BI expression in selectively controlling the utilization of HDL cholesterol for biliary secretion. In contrast, SR-BI expression is not essential for intestinal cholesterol absorption.


Assuntos
Ácidos e Sais Biliares/metabolismo , Antígenos CD36/fisiologia , Colesterol/metabolismo , Absorção Intestinal , Fígado/metabolismo , Proteínas de Membrana , Receptores Imunológicos , Receptores de Lipoproteínas , Animais , Northern Blotting , Antígenos CD36/genética , Colesterol/sangue , Masculino , Camundongos , Camundongos Knockout , Receptores Depuradores , Receptores Depuradores Classe B
9.
Gastroenterology ; 119(6): 1708-19, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11113092

RESUMO

BACKGROUND & AIMS: Sterol carrier protein 2 (SCP-2) enhances sterol cycling and facilitates cholesterol translocation between intracellular organelles and plasma membrane in cultured cells, including hepatocytes. We examined the role of SCP-2 in hepatic cholesterol and lipid trafficking through the sinusoidal and canalicular secretory pathways of the liver in vivo. METHODS: Recombinant adenovirus-mediated SCP-2 gene transfer was used to obtain hepatic overexpression of SCP-2 in C57BL/6 mice. RESULTS: SCP-2 overexpression in the mouse liver resulted in an 8-fold increase of SCP-2 protein levels and determined various effects on lipid metabolism. It decreased high-density lipoprotein cholesterol and increased low-density lipoprotein (LDL) cholesterol concentrations. The expressions of hepatic LDL receptor, apolipoprotein (apo) A-I, apoB, and apoE were decreased. SCP-2 overexpression also increased hepatic cholesterol concentration, associated with decreased cholesterol neosynthesis. Increased biliary cholesterol and bile acid secretion, bile acid pool size, and intestinal cholesterol absorption were also observed. CONCLUSIONS: These results indicate that modulation of SCP-2 expression in the liver determines important modifications on lipoprotein metabolism, hepatic cholesterol synthesis and storage, biliary lipid secretion, bile acid metabolism, and intestinal cholesterol absorption.


Assuntos
Proteínas de Transporte/farmacologia , Metabolismo dos Lipídeos , Circulação Hepática/efeitos dos fármacos , Fígado/metabolismo , Proteínas de Plantas , Esteróis/sangue , Animais , Apolipoproteínas/metabolismo , Bile/metabolismo , Ácidos e Sais Biliares/metabolismo , Proteínas de Transporte/genética , Colesterol/metabolismo , Técnicas de Transferência de Genes , Absorção Intestinal/efeitos dos fármacos , Lipoproteínas LDL/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL
10.
Neurosci Lett ; 291(3): 155-8, 2000 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-10984630

RESUMO

Due to the hypothetical role of ovarian hormones, estrogen and progesterone, in cocaine-induced behavioral activity and self-administration, this study investigated the effects of cocaine, estrogen, and progesterone administration on monoamine levels in the medial prefrontal cortex of ovariectomized hormone-treated rats. Rats were given either 'binge' cocaine or saline, and one of four hormone treatments: vehicle, estrogen, progesterone, or estrogen+progesterone. The co-administration of progesterone and cocaine resulted in increased levels of serotonin when compared to saline-treated controls and cocaine-treated animals in the other hormone-treatment groups. Further, progesterone-treated rats had higher levels of 5-HIAA than vehicle or estrogen-treated rats. Although levels of dopamine, DOPAC, and homovanillic acid were decreased after cocaine, these alterations failed to reach significance. These results show an interaction between the endocrine environment and cocaine-induced alterations in serotonin system in the medial prefrontal cortex. Thus, these changes may contribute to previously reported gender and estrous cycle differences in behavioral responses to cocaine.


Assuntos
Cocaína/administração & dosagem , Ovariectomia , Córtex Pré-Frontal/efeitos dos fármacos , Progesterona/administração & dosagem , Serotonina/metabolismo , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Animais , Dopamina/metabolismo , Estrogênios/administração & dosagem , Feminino , Ácido Homovanílico/metabolismo , Ácido Hidroxi-Indolacético/metabolismo , Injeções Intraperitoneais , Injeções Subcutâneas , Norepinefrina/metabolismo , Córtex Pré-Frontal/metabolismo , Ratos , Ratos Endogâmicos F344
11.
Gastroenterology ; 118(4): 772-9, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10734029

RESUMO

BACKGROUND & AIMS: Because apolipoprotein E (apoE) is a key cholesterol transport molecule involved in the hepatic uptake of chylomicron cholesterol, it may play a critical role in controlling bile cholesterol elimination and cholesterol gallstone formation induced by dietary cholesterol. To test this hypothesis, we studied biliary lipid secretion and gallstone formation in apoE-deficient mice fed cholesterol-rich diets. METHODS: Bile lipid outputs and gallstone sequence events were analyzed in apoE-deficient mice fed a high-cholesterol diet or a lithogenic diet compared with control animals. RESULTS: A high-cholesterol diet increased biliary cholesterol secretion and gallbladder bile cholesterol concentration in wild-type mice; the increase in bile cholesterol secretion was significantly attenuated in apoE-deficient mice. ApoE knockout mice fed a high-cholesterol lithogenic diet had a markedly lower frequency of gallbladder bile cholesterol crystal and gallstone formation than wild-type mice, which was most likely a result of the decreased cholesterol saturation index found in gallbladder bile of apoE-deficient mice. CONCLUSIONS: These results show that apoE expression is an important factor for regulating both biliary secretion of diet-derived cholesterol as well as diet-induced cholesterol gallstone formation in mice.


Assuntos
Apolipoproteínas E/deficiência , Bile/metabolismo , Colelitíase/prevenção & controle , Colesterol na Dieta/administração & dosagem , Colesterol/metabolismo , Animais , Apolipoproteínas E/genética , Apolipoproteínas E/fisiologia , Ácidos e Sais Biliares/metabolismo , Colelitíase/etiologia , Colesterol/sangue , Colesterol na Dieta/farmacologia , Dieta , Vesícula Biliar/metabolismo , Metabolismo dos Lipídeos , Lipoproteínas/sangue , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout/genética
12.
Oncol Nurs Forum ; 25(6): 1049-55; quiz 1056-7, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9679263

RESUMO

PURPOSE/OBJECTIVES: To provide a comprehensive understanding of allogeneic peripheral blood stem cell transplantation (PBSCT), the new modality for treating advanced hematologic malignancies. DATA SOURCE: Journal articles/abstracts, published literature, clinical experience. DATA SYNTHESIS: Growth factor mobilization and apheresis is well tolerated by donors and supplies adequate numbers of stem cells for engraftment. Patients engraft sooner using PBSCT compared to bone marrow transplant (BMT). CONCLUSIONS: Allogeneic PBSCT is a safe alternative to BMT and has distinct advantages for donors and recipients. Faster engraftment results in fewer transfusions, shorter hospitalization, and decreased cost. Future research to determine if long-term side effects from growth factors will negatively affect donors is essential. Data regarding durability of hematopoiesis and incidence of graft versus host disease warrant further analysis. IMPLICATIONS FOR NURSING PRACTICE: Care for patients is similar to that of standard BMT; however, care for donors is unique. Shorter hospitalization requires nurses to alter content and timing of patient education and preparation for discharge.


Assuntos
Educação Continuada em Enfermagem , Transplante de Células-Tronco Hematopoéticas , Remoção de Componentes Sanguíneos , Custos e Análise de Custo , Doença Enxerto-Hospedeiro/enfermagem , Doença Enxerto-Hospedeiro/prevenção & controle , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Transplante de Células-Tronco Hematopoéticas/enfermagem , Humanos , Doadores de Tecidos , Transplante Homólogo , Resultado do Tratamento
13.
Plant Mol Biol ; 31(4): 937-43, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8806426

RESUMO

The L5 ribosomal protein gene (rpl5) and a S14 ribosomal protein pseudogene were identified by sequence analysis in the potato mitochondrial genome. The two genes are separated by one nucleotide and are found upstream of the apocytochrome b gene (cob), an arrangement conserved also in Arabidopsis and Brassica. The rpl5 gene has an intact open reading frame while the rps14 locus is disrupted by a five nucleotide duplication that introduces a frameshift in the reading frame. Editing of rpl5 and pseudorps14 cotranscripts has been studied by cDNA sequence analysis. Eight C residues are edited into U in the rpl5 coding region, resulting in eight amino acid changes that increase the homology between potato and other RPL5 polypeptides. Interestingly, the rps14 pseudogene sequence is not edited at any nucleotide position.


Assuntos
Genes de Plantas/genética , Pseudogenes/genética , Proteínas Ribossômicas/genética , Solanum tuberosum/genética , Sequência de Aminoácidos , Apoproteínas/genética , Sequência de Bases , Grupo dos Citocromos b/genética , Citocromos b , DNA Mitocondrial/genética , DNA de Plantas/genética , Mitocôndrias , Dados de Sequência Molecular , Fases de Leitura Aberta/genética , RNA/análise , Edição de RNA/fisiologia , RNA Mitocondrial , RNA de Plantas/análise , Mapeamento por Restrição , Análise de Sequência de DNA
15.
Curr Genet ; 27(6): 565-71, 1995 May.
Artigo em Inglês | MEDLINE | ID: mdl-7553943

RESUMO

The structure and expression of the potato mitochondrial gene rps10, encoding ribosomal protein S10, has been characterized. The RPS10 polypeptide of 129 amino acids is encoded by two exons of 307 bp and 80 bp respectively, which are separated by a 774-bp class-II intron. Editing of the complete rps10 coding region was studied by sequence analysis of spliced cDNAs. Four C residues are edited into U, resulting in the creation of a putative translational initiation codon, a new stop codon which eliminated ten carboxy-terminal residues, and two additional amino-acid alterations. All these changes increase the similarity between the potato and liverwort polypeptides. One additional C-to-U RNA editing event, observed in the intron sequence of unspliced cDNAs, improves the stability of the secondary structure in stem I (i) of domain I and may thus be required for the splicing reaction. All spliced cDNAs, and most unspliced cDNAs, were completely edited, suggesting that editing is an early step of rps10 mRNA processing and precedes splicing. Earlier work on potato rps10 (Zanlungo et al. 1994) is now known to comprise only a partial analysis of the gene, since the short downstream exon was not identified.


Assuntos
Proteínas de Plantas/genética , Edição de RNA/genética , Splicing de RNA/genética , Proteínas Ribossômicas/genética , Solanum tuberosum/genética , Solanum tuberosum/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Códon/genética , Primers do DNA/genética , DNA Complementar/genética , DNA Mitocondrial/genética , DNA de Plantas/genética , Éxons , Genes de Plantas , Íntrons , Dados de Sequência Molecular , Conformação de Ácido Nucleico , RNA de Plantas/química , RNA de Plantas/genética , RNA de Plantas/metabolismo , Homologia de Sequência de Aminoácidos , Transcrição Gênica
16.
J Histochem Cytochem ; 42(12): 1533-7, 1994 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7983354

RESUMO

We describe a novel double-labeling method to simultaneously investigate proliferation and apoptosis from plastic-embedded biopsy specimens (PEBs). Infusions of bromo- and/or iododeoxyuridine (BrdU/IudR) were given to 10 patients, five with acute myeloid leukemia (AML) and five with myelodysplastic syndromes (MDS), and S-phase cells were measured in PEBs using a monoclonal anti-IudR/BrdU antibody. Apoptosis was measured by in situ end-labeling (ISEL) of DNA. The results demonstrate that both AML and MDS are highly proliferative disorders but that there is almost no apoptosis in the former, whereas extensive apoptosis was observed in the latter. Double labeling revealed that large numbers of S-phase cells in MDS were simultaneously undergoing apoptosis. We conclude that the high cell death in MDS cancels the high cell birth, resulting in a functionally aplastic marrow and thus accounting for the observed ineffective hematopoiesis. On the other hand, AML is rapidly fatal, probably owing to high cell birth with no or minimal cell death. Therapeutic strategies to prevent intramedullary programmed cell death of hematopoietic precursors should be evaluated in MDS, and efficacy of chemotherapy in AML can be assessed by measuring the induction of apoptosis in post-treatment biopsy specimens.


Assuntos
Apoptose , Divisão Celular , Células-Tronco Hematopoéticas/patologia , Leucemia Mieloide/patologia , Síndromes Mielodisplásicas/patologia , Doença Aguda , Medula Óssea/patologia , Bromodesoxiuridina , DNA/análise , DNA de Neoplasias/análise , Humanos , Idoxuridina , Fase S
17.
Plant Mol Biol ; 25(4): 743-9, 1994 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8061325

RESUMO

The S10 ribosomal protein gene (rps10), which has not been previously reported in any angiosperm mitochondrial genome, was identified by sequence analysis in the potato mitochondrial DNA. This gene is found downstream of a truncated non-functional apocytochrome b (cob) pseudogene, and is expressed as multiple transcripts ranging in size from 0.8 to 5.0 kb. Southern hybridization analysis indicates that rps10-homologous sequences are not present in the wheat mitochondrial genome. Sequence analysis of a single-copy region of the pea mitochondrial genome located upstream of cox1 [11] shows that a non-functional rps10 pseudogene is present in this species. These results suggest that the functional genes coding for wheat and pea mitochondrial RPS10 polypeptides have been translocated to the nucleus.


Assuntos
DNA Mitocondrial/metabolismo , Genes de Plantas , Pseudogenes , Proteínas Ribossômicas/biossíntese , Solanum tuberosum/genética , Sequência de Aminoácidos , Sequência de Bases , Northern Blotting , Escherichia coli/metabolismo , Mitocôndrias/metabolismo , Dados de Sequência Molecular , Plantas/metabolismo , Mapeamento por Restrição , Proteínas Ribossômicas/genética , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido Nucleico , Solanum tuberosum/metabolismo , Transcrição Gênica
18.
Curr Genet ; 24(4): 344-8, 1993 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7504589

RESUMO

Editing of the complete coding region of cob transcripts from two genera of plants has been studied by cDNA sequence analysis. Eighteen and nine C residues are edited into U in the mitochondrial transcripts from wheat and potato respectively. Both systems share eight common editing sites; ten codons edited in wheat are "pre-edited" at the genomic level in potato, and one codon edited in potato is "pre-edited" in wheat. Most amino-acid modifications lead to hydrophobic residues and increase the homology between the COB polypeptides and the corresponding protein of other species. In two out of the nine potato cDNA clones, an additional C-to-T modification, which also leads to a change in the encoded amino acid, was identified. Heterogeneity observed at the carboxy-terminus of the COB open reading frame in Triticum aestivum and Triticum timopheevi is not corrected by editing.


Assuntos
Apoproteínas/genética , Grupo dos Citocromos b/genética , Plantas/genética , Edição de RNA , RNA/genética , Transcrição Gênica , Sequência de Bases , Citocromos b , DNA , Éxons , Mitocôndrias/metabolismo , Dados de Sequência Molecular , RNA Mitocondrial , Homologia de Sequência de Aminoácidos
19.
In. Sánchez Quiñonez, V. A; Toledo González, G. Estado convulsivo. Cienfuegos, Finlay, 1991. p.26-7.
Monografia em Espanhol | LILACS | ID: lil-267517
20.
Biochemistry ; 29(19): 4548-53, 1990 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-2196937

RESUMO

Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase [ATP:oxaloacetate carboxy-lyase (transphosphorylating), EC 4.1.1.49] is inactivated by the fluorescent sulfhydryl reagent N-(iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine (1,5-IAEDANS). The inactivation reaction follows pseudo-first-order kinetics with respect to active enzyme to less than 10% remaining enzyme activity, with a second-order inactivation rate constant of 2.6 min-1 mM-1 at pH 7.5 and 30 degrees C. A stoichiometry of 1.05 mol of reagent incorporated per mole of enzyme subunit was found for the completely inactivated enzyme. Almost complete protection of the enzyme activity and of dansyl label incorporation are afforded by MnADP or MnATP, thus suggesting that 1,5-IAEDANS interacts with an enzyme sulfhydryl group at the nucleotide binding site. The fluorescence decay of the AEDANS attached to the protein shows a single-exponential behavior with a lifetime of 18 ns. A comparison of the fluorescence band position and the fluorescence decay with those of the adduct AEDANS-acetylcysteine indicates a reduced polarity for the microenvironment of the substrate binding site. The quenching of the AEDANS moiety in the protein can be described in terms of a collisional and a static component. The rate constant for the collisional component is much lower than that obtained for the adduct in a medium of reduced polarity. These last results indicate that the AEDANS moiety is considerably shielded from the solvent when it is covalently attached to PEPCK.


Assuntos
Fosfoenolpiruvato Carboxiquinase (GTP)/metabolismo , Saccharomyces cerevisiae/enzimologia , Sítios de Ligação , Corantes Fluorescentes , Cinética , Naftalenossulfonatos/farmacologia , Nucleotídeos , Fosfoenolpiruvato Carboxiquinase (GTP)/antagonistas & inibidores , Espectrometria de Fluorescência
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