RESUMEN
PURPOSE: The aim of the present study was to evaluate the role of hypothyroidism as a cause of hyponatremia in a clinical model of iatrogenic acute hypothyroidism due to thyroid hormone withdrawal prior to ablative radioactive iodine (RAI) therapy after total thyroidectomy. METHODS: The study group consisted of 101 differentiated thyroid cancer (DTC) patients (77 women and 24 men). Plasma concentration of thyroid-stimulating hormone ([TSH]) and sodium ([Na+]) was evaluated before total thyroidectomy (pre[TSH] and pre[Na+]) and on the day of RAI therapy (post[TSH] and post[Na+]). RESULTS: The frequency of hypothyroidism-associated hyponatremia was 4 % (4/101). Pre[Na+] was significantly higher than post[Na+] (140.7 ± 1.6 vs 138.7 ± 2.3 mEq/L, p = 0.012). Moreover, a linear correlation was identified between pre[Na+] and post[Na+]. CONCLUSIONS: Iatrogenic acute hypothyroidism-related hyponatremia is uncommon. However, because of the significant reduction of [Na+] in the transition from euthyroidism to iatrogenic hypothyroidism, the value of pre[Na+] should be viewed as a parameter to be considered. Since it acts as an independent risk factor for the development of hyponatremia, patients with a pre[Na+] close to the lower limit of normal range may deserve a closer monitoring of [Na+].
Asunto(s)
Hiponatremia/radioterapia , Hipotiroidismo/radioterapia , Radioisótopos de Yodo/uso terapéutico , Complicaciones Posoperatorias/radioterapia , Neoplasias de la Tiroides/cirugía , Tiroidectomía/efectos adversos , Enfermedad Aguda , Femenino , Humanos , Hiponatremia/etiología , Hipotiroidismo/etiología , Enfermedad Iatrogénica , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Retrospectivos , Neoplasias de la Tiroides/complicacionesRESUMEN
OBJECTIVE: Insulin sensitivity and secretion during early and late pregnancy were assessed in women with normal glucose tolerance and gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS: The oral glucose tolerance test (OGTT) was performed in 903 women at 16-20th gestational week, of whom 37 had GDM (GDM1 group), and 859 repeated the OGTT at wk 26-30. At the second test, 55 had GDM (GDM2 group); the others remained normotolerant (ND group). Insulin sensitivity from OGTT (as quantitative insulin sensitivity check index and OGTT insulin sensitivity) and beta-cell function (as the ratio of the areas under the insulin and glucose concentration curves, adjusted for insulin sensitivity) were assessed in both tests. RESULTS: In early pregnancy the quantitative insulin sensitivity check index was not different in the three groups, whereas OGTT insulin sensitivity was lowest in GDM2, intermediate in GDM1, and highest in ND. In late pregnancy both indices were reduced in GDM compared with ND and lower than in early pregnancy. In early pregnancy GDM1, but not GDM2, had lower beta-cell function than ND. During the late visit, GDM2 also showed impaired beta-cell function compared with ND; furthermore, the adaptation to the increase to insulin resistance from early to late pregnancy was defective in GDM2. CONCLUSIONS: In early pregnancy insulin sensitivity, as assessed from the OGTT but not from fasting measurements, is impaired in women who developed GDM. beta-Cell function impairment is evident only when GDM is manifest and is characterized by inappropriate adaptation to the pregnancy induced increase in insulin resistance.
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Diabetes Gestacional/metabolismo , Resistencia a la Insulina , Células Secretoras de Insulina/fisiología , Femenino , Prueba de Tolerancia a la Glucosa , Humanos , Estudios Longitudinales , EmbarazoAsunto(s)
Puntaje de Gravedad del Traumatismo , Heridas y Lesiones/mortalidad , Femenino , Humanos , MasculinoRESUMEN
BACKGROUND: The adoption of the International Diabetes Federation (IDF) criteria for metabolic syndrome (MS), in comparison with the National Cholesterol Educational Program (NCEP) criteria, produces different changes in estimates of prevalence in diverse populations. Few data are available in Caucasian non-diabetic subjects. PATIENTS AND METHODS: The prevalence of NCEP- and IDF-defined MS was assessed in a sample of 2,945 individuals, aged 55.2+/-11.5 yr, enrolled in a screening program for diabetes. Association of different definitions of MS with glucose intolerance (120-min glucose 7.8 mmol/l after a 75 g-oral glucose load) and hyperuricemia (>0.38 mmol/l) was also assessed. RESULTS: The prevalence of MS was 16.6% and 29.7% with NCEP and IDF definitions, respectively. The prevalence of NCEP-defined MS was higher than IDF-MS through all age ranges; among those aged >60 yr, the prevalence of IDF-MS reached 52.8% (vs 33.1% for NCEP-MS). Both NCEP- and IDF-MS were associated with glucose intolerance and hyperuricemia. Individuals fulfilling IDF, but not NCEP criteria for MS, showed a prevalence of glucose intolerance (22.7%) significantly (p<0.05) lower than those fulfilling NCEP criteria only (31.6%) or both sets of criteria (31.8%). CONCLUSION: In Caucasian subjects without known diabetes, IDF criteria produce a relevant increase in estimates of prevalence of MS, particularly in older subjects, when compared with NCEP criteria. NCEP-MS seems to be more effective than IDF-MS in the identification of glucose intolerant subjects.
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Síndrome Metabólico/diagnóstico , Síndrome Metabólico/epidemiología , Programas Nacionales de Salud , Adulto , Anciano , Estudios de Cohortes , Diabetes Mellitus/sangre , Diabetes Mellitus/diagnóstico , Diagnóstico Diferencial , Femenino , Intolerancia a la Glucosa/sangre , Intolerancia a la Glucosa/diagnóstico , Humanos , Hiperuricemia/sangre , Hiperuricemia/diagnóstico , Italia/epidemiología , Masculino , Tamizaje Masivo , Síndrome Metabólico/fisiopatología , Persona de Mediana Edad , Prevalencia , Relación Cintura-CaderaRESUMEN
BACKGROUND: Skeletal muscle disorders associated with mutations of lamin A/C gene include autosomal Emery-Dreifuss muscular dystrophy and limb girdle muscular dystrophy 1B. The pathogenic mechanism underlying these diseases is unknown. Recent data suggest an impairment of signalling mechanisms as a possible cause of muscle malfunction. A molecular complex in muscle cells formed by lamin A/C, emerin, and nuclear actin has been identified. The stability of this protein complex appears to be related to phosphorylation mechanisms. OBJECTIVE: To analyse lamin A/C phosphorylation in control and laminopathic muscle cells. METHODS: Lamin A/C N-terminal phosphorylation was determined in cultured mouse myoblasts using a specific antibody. Insulin treatment of serum starved myoblast cultures was carried out to evaluate involvement of insulin signalling in the phosphorylation pathway. Screening of four Emery-Dreifuss and one limb girdle muscular dystrophy 1B cases was undertaken to investigate lamin A/C phosphorylation in both cultured myoblasts and mature muscle fibres. RESULTS: Phosphorylation of lamin A was observed during myoblast differentiation or proliferation, along with reduced lamin A/C phosphorylation in quiescent myoblasts. Lamin A N-terminus phosphorylation was induced by an insulin stimulus, which conversely did not affect lamin C phosphorylation. Lamin A/C was also hyperphosphorylated in mature muscle, mostly in regenerating fibres. Lamin A/C phosphorylation was strikingly reduced in laminopathic myoblasts and muscle fibres, while it was preserved in interstitial fibroblasts. CONCLUSIONS: Altered lamin A/C interplay with a muscle specific phosphorylation partner might be involved in the pathogenic mechanism of Emery-Dreifuss muscular dystrophy and limb girdle muscular dystrophy 1B.
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Lamina Tipo A/metabolismo , Distrofia Muscular de Emery-Dreifuss/metabolismo , Mioblastos/metabolismo , Procesamiento Proteico-Postraduccional , Animales , Diferenciación Celular , Línea Celular , Humanos , Insulina/metabolismo , Lamina Tipo A/genética , Ratones , Fibras Musculares Esqueléticas/metabolismo , Distrofia Muscular de Cinturas/genética , Distrofia Muscular de Cinturas/metabolismo , Distrofia Muscular de Cinturas/patología , Distrofia Muscular de Emery-Dreifuss/genética , Fosforilación , Transducción de SeñalRESUMEN
Previous investigations have demonstrated the existence of an autonomous intranuclear inositide cycle endowed with conventional lipid kinases and phospholipase C (PLC) which is the isoform beta in Swiss 3T3 cells, PC12 pheochromocytoma cells, human osteosarcoma SaOS-2 cells, and rat liver. The presence of PLC has been investigated in nuclei of Friend erythroleukemia cells. Both beta and gamma isoforms are present in these nuclei. When Friend cells undergo terminal erythroid differentiation in the presence of dimethyl sulfoxide the PLC beta isoform is down-regulated as shown by immunochemical and immunocytochemical analysis, by determination of enzymatic activity directly and in the presence of neutralizing monoclonal antibodies and also by Northern blot for PLC beta message. By contrast, the amount of PLC gamma and its activity are unaffected by erythroid differentiation. Thus, the presence of a nuclear PLC beta, the activity and expression of which are modulated during differentiation of erythroleukemia cells, implicates a role for nuclear phosphoinositide signaling in the processes of cell determination and indicates the nuclear PLC beta as a key enzyme of the cycle in relation to the erythroid differentiative commitment of murine erythroleukemia cells.
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Núcleo Celular/enzimología , Virus de la Leucemia Murina de Friend , Isoenzimas/metabolismo , Leucemia Eritroblástica Aguda/enzimología , Leucemia Eritroblástica Aguda/patología , Fosfolipasas de Tipo C/metabolismo , Animales , Anticuerpos Monoclonales , Western Blotting , Diferenciación Celular , Regulación hacia Abajo , Ratones , ARN Mensajero/metabolismo , Células Tumorales CultivadasRESUMEN
OBJECTIVES: The recent guideline for the evaluation and management of Chronic Kidney Disease recommends assessing GFR employing equations based on serum creatinine; despite this, creatinine clearance 24-hour urine collection is used routinely in many settings. In this study we compared the classification assessed from CrCl (creatinine clearance 24h urine collection) and e-GFR calculated with CKD-EPI or MDRD formulas. DESIGN AND METHODS: In this retrospective study we analyze consecutive laboratory data: creatinine clearance 24h urine collection, serum creatinine and demographic data such as sex and age from 15,777 patients >18 years of age collected from 2011 to 2013 in our laboratory at Careggi Hospital. The results were then compared to the estimated GFR calculated with the equations according to the recent treatment guidelines. Consecutive and retrospective laboratory data (creatinine clearance 24h urine collection, serum creatinine and, demographic data such as sex and age) from 15,777 patients >18 years of age seen at Careggi Hospital were collected. RESULTS: Comparison between e-GFR calculated with CKD-EPI or MDRD formulas and GFR according CrCl determinations and bias [95% CI] were 11.34 [-47,4/70.1] and 11.4 [-50.2/73] respectively. The concordance for 18/65 years aged group when compared with e-GFR classification between MDRD vs CKDEPI, MDRD vs CrCl and CKD-EPI vs CrCl were 0.78, 0.34, and 0.41 respectively, while in the 65/110years aged group the concordance Kappas were 0.84, 0.38, and 0.36 respectively. CONCLUSIONS: The use of CrCl provides a different classification than the estimation of GFR using a prediction equation. The CrCl is unreliable when it is necessary to identify CKD subjects with decrease of GFR of 5ml/min/1.73m(2)/year.
Asunto(s)
Creatinina/orina , Fallo Renal Crónico/clasificación , Adulto , Anciano , Femenino , Tasa de Filtración Glomerular , Humanos , Fallo Renal Crónico/fisiopatología , Fallo Renal Crónico/orina , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
OBJECTIVE: To evaluate the effects of metformin on glucagon-like peptide 1 (GLP-1) and leptin levels. RESEARCH DESIGN AND METHODS: A total of 10 obese nondiabetic male patients were studied before and after a 14-day treatment with 2,550 mg/day metformin and were compared with 10 untreated obese control subjects. On days 0 and 15, leptin and GLP-1(7-36)amide/(7-37) levels were assessed before and after an oral glucose load during a euglycemic hyperinsulinemic clamp to avoid the interference of variations of insulinemia and glycemia on GLP-1 and leptin secretion. The effects of metformin on GLP-1(7-36)amide degradation in human plasma and in a buffer solution containing dipeptidyl peptidase IV (DPP-IV) were also studied. RESULTS: Leptin levels were not affected by the oral glucose load, and they were not modified after metformin treatment. Metformin induced a significant (P < 0.05) increase of GLP-1(7-36)amide/(7-37) at 30 and 60 min after the oral glucose load (63.8 +/- 29.0 vs. 50.3 +/- 15.6 pmol/l and 75.8 +/- 35.4 vs. 46.9 +/- 20.0 pmol/l, respectively), without affecting baseline GLP-1 levels. No variations of GLP-1 levels were observed in the control group. In pooled human plasma, metformin (0.1-0.5 microg/ml) significantly inhibited degradation of GLP-1(7-36)amide after a 30-min incubation at 37 degrees C; similar results were obtained in a buffer solution containing DPP-IV. CONCLUSIONS: Metformin significantly increases GLP-1 levels after an oral glucose load in obese nondiabetic subjects; this effect could be due to an inhibition of GLP-1 degradation.
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Leptina/sangre , Metformina/uso terapéutico , Obesidad/sangre , Obesidad/tratamiento farmacológico , Fragmentos de Péptidos/sangre , Péptidos/sangre , Adolescente , Adulto , Glucemia/metabolismo , Glucagón , Péptido 1 Similar al Glucagón , Péptidos Similares al Glucagón , Técnica de Clampeo de la Glucosa , Humanos , Hipoglucemiantes/uso terapéutico , Masculino , Persona de Mediana EdadRESUMEN
The MDR1 gene product P-glycoprotein is a plasma membrane efflux pump which is responsible for multiple drug resistance of cancer cells. Although the ability of multidrug-resistant cells to exclude drugs from the nucleus is a distinctive and possibly the main mechanism for resistance against a number of drugs, including doxorubicin, this phenomenon is not entirely understood. In this paper, the relationship between doxorubicin subcellular distribution and P-glycoprotein activity at different cell sites has been investigated by different techniques. Cytofluorometry and confocal microscopy were used to study doxorubicin subcellular distribution in U-2 OS human osteosarcoma cells and in the multidrug-resistant variant U-2 OS/DX580. Stable levels of doxorubicin accumulation were found in the nuclei of sensitive cells, whereas the absence of detectable levels of drug in the nuclei of resistant cells could be attributed to an energy-dependent mechanism. Moreover, in resistant cells, inhibition of P-glycoprotein activity was able to induce drug accumulation in the nuclei of resistant cells and to achieve cytotoxic effects comparable to those observed in sensitive cells. Similar results were also found in isolated nuclei from U-2 OS/DX580 cells. The expression of P-glycoprotein in U-2 OS/DX580 and in two other multidrug-resistant cell lines (SW948-R-300 and LoVo-R-100) was investigated by confocal microscopy and immunoelectron microscopy, by using a panel of monoclonal antibodies directed against this protein. Higher levels of P-glycoprotein expression, not only in the plasma membrane and inside the cytoplasm, but also in the nucleus, were found in U-2 OS/DX580 and in LoVo-R-100 multidrug-resistant cells compared to their corresponding sensitive cells. SW948-R-300 cells, featuring increased amounts of MDR1 mRNA but lacking P-glycoprotein expression at the cell surface, showed a higher P-glycoprotein immunolabeling only in the nucleus and in the cytoplasm. The localization of P-glycoprotein in the nucleus of multidrug-resistant cells was confirmed also by studies on isolated nuclei and nuclear matrices, and by Western blot analysis on total cell and isolated nuclear extracts. These findings, suggesting the possible involvement of nuclear P-glycoprotein in the regulation of subcellular doxorubicin distribution in multidrug-resistant cells, open new insights on the mechanisms of P-glycoprotein-mediated resistance to anticancer drugs.
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Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/análisis , Antibióticos Antineoplásicos/farmacocinética , Núcleo Celular/química , Doxorrubicina/farmacocinética , Resistencia a Múltiples Medicamentos/fisiología , Carcinoma , Neoplasias del Colon , Doxorrubicina/toxicidad , Humanos , Matriz Nuclear/química , Osteosarcoma , Células Tumorales Cultivadas , Verapamilo/farmacologíaRESUMEN
The existence of a signal transduction system in the nucleus, based on polyphosphoinositide breakdown mediated by specific phosphoinositidases (PLC), has been widely documented. In different cell systems, nuclear PLCs can be modulated, in response to agonists, either by enhancing or by down-regulating their activity, thus leading to DNA replication or to cell differentiation. Friend cells, induced to erythroid differentiation by dimethyl sulfoxide (DMSO), show a down-regulation of PLC beta 1 isoform, as indicated by the reduction of the transcription of its mRNA and of the in vitro synthesis of its translation product. The intracellular localization and the amount of different PLC isoforms have been evaluated by electron microscope immunocytochemistry. In untreated Friend cells, PLC beta 1 and gamma 1 isoforms are both present within the nucleus, whereas mainly the gamma 1 isoform is detected in the cytoplasm. The small amount of cytoplasmic PLC beta 1 is probably representative only of the newly synthesized enzyme. Quantitative immunolabeling analyses demonstrate that erythroid differentiation is associated with a significant decrease of the PLC beta 1 amount in the nucleus and with an almost complete disappearance of that isoform in the cytoplasm, whereas the PLC gamma 1 isoform is unaffected. The two PLC isoforms, moreover, appear to be differently associated with the nuclear components, PLC beta 1 being steadily bound to the inner nuclear matrix, whereas PLC gamma 1 is almost completely soluble.
Asunto(s)
Núcleo Celular/enzimología , Isoenzimas/metabolismo , Leucemia Eritroblástica Aguda/metabolismo , Fosfolipasas de Tipo C/metabolismo , Animales , Diferenciación Celular/efectos de los fármacos , Dimetilsulfóxido , Isoenzimas/genética , Leucemia Eritroblástica Aguda/patología , Ratones , Microscopía Inmunoelectrónica , Fosfolipasa C beta , Fosfolipasa C gamma , Biosíntesis de Proteínas/efectos de los fármacos , ARN Mensajero/biosíntesis , Células Tumorales Cultivadas , Fosfolipasas de Tipo C/genéticaRESUMEN
Fibronectin is one of the main components of the extracellular matrix and associates with a variety of other matrix molecules including collagens. We demonstrate that the absence of secreted type VI collagen in cultured primary fibroblasts affects the arrangement of fibronectin in the extracellular matrix. We observed a fine network of collagen VI filaments and fibronectin fibrils in the extracellular matrix of normal murine and human fibroblasts. The two microfibrillar systems did not colocalize, but were interconnected at some discrete sites which could be revealed by immunoelectron microscopy. Direct interaction between collagen VI and fibronectin was also demonstrated by far western assay. When primary fibroblasts from Col6a1 null mutant mice were cultured, collagen VI was not detected in the extracellular matrix and a different pattern of fibronectin organization was observed, with fibrils running parallel to the long axis of the cells. Similarly, an abnormal fibronectin deposition was observed in fibroblasts from a patient affected by Bethlem myopathy, where collagen VI secretion was drastically reduced. The same pattern was also observed in normal fibroblasts after in vivo perturbation of collagen VI-fibronectin interaction with the 3C4 anti-collagen VI monoclonal antibody. Competition experiments with soluble peptides indicated that the organization of fibronectin in the extracellular matrix was impaired by added soluble collagen VI, but not by its triple helical (pepsin-resistant) fragments. These results indicate that collagen VI mediates the three-dimensional organization of fibronectin in the extracellular matrix of cultured fibroblasts.
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Colágeno Tipo VI/metabolismo , Matriz Extracelular/metabolismo , Fibroblastos/metabolismo , Fibronectinas/metabolismo , Animales , Células de la Médula Ósea/citología , Células de la Médula Ósea/metabolismo , Células Cultivadas , Colágeno Tipo VI/genética , Fibroblastos/citología , Humanos , Ratones , Ratones Noqueados , Ratones DesnudosRESUMEN
Emerin is a nuclear membrane-anchored protein which is absent or mutated in patients affected by Emery-Dreifuss muscular dystrophy. In this study, we induced apoptosis in cultured mouse myoblasts to evaluate emerin fate during the nuclear destabilization involved in programmed cell death. Emerin proteolysis was observed in myocytes during the apoptotic process. Myoblast apoptosis and emerin degradation were associated with chromatin compaction and detachment from the nuclear lamina, as detected by electron microscopy. In vivo specific inhibition of caspase 3 or caspase 6 activity completely abolished emerin proteolysis. These results show that the process of programmed cell death in muscle cells leads to emerin proteolysis, which appears to be related to caspase 6 activation and to cleavage of other nuclear envelope proteins, that share sequence homologies or functional features with emerin.
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Caspasas/metabolismo , Proteínas de la Membrana/metabolismo , Músculos/efectos de los fármacos , Músculos/metabolismo , Procesamiento Proteico-Postraduccional/efectos de los fármacos , Estaurosporina/farmacología , Timopoyetinas/metabolismo , Animales , Apoptosis/efectos de los fármacos , Caspasa 3 , Inhibidores de Caspasas , Línea Celular , Medio de Cultivo Libre de Suero , Cinética , Ratones , Microscopía Electrónica , Microscopía Fluorescente , Músculos/enzimología , Músculos/ultraestructura , Proteínas Nucleares , Factores de TiempoRESUMEN
Interleukin 1 (IL-1) delivers a stimulatory signal which increases the expression of a set of genes by modulating the transcription factor NF-kappaB. The IL-1 receptors are transmembrane glycoproteins which lack a catalytic domain. The C-terminal portion of the type I IL-1 receptor (IL-IRI) is essential for IL-1 signalling and for IL-1 dependent activation of NF-kappaB. This portion contains a putative phosphatidylinositol 3-kinase (PI 3-kinase) binding domain (Tyr-E-X-Met), which is highly conserved between the human, mouse and chicken sequences, as well as the related cytoplasmic domain of the Drosophila receptor Toll. This observation prompted us to investigate the role of PI 3-kinase in IL-1 signalling. Here we report evidence that PI 3-kinase is recruited by the activated IL-IRI, causing rapid and transient activation of PI 3-kinase. We also show that the receptor is tyrosine phosphorylated in response to IL-1. Expression of a receptor mutant lacking the putative binding site for p85 demonstrates that Tyr479 in the receptor cytoplasmic domain is essential for PI 3-kinase activation by IL-1. Our results indicate that PI 3-kinase is likely to be an important mediator of some IL-1 effects, providing docking sites for additional signalling molecules.
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Interleucina-1/farmacología , Fosfatidilinositol 3-Quinasas/metabolismo , Receptores de Interleucina-1/metabolismo , Sitios de Unión , Secuencia de Consenso , Activación Enzimática , Humanos , Interleucina-1/metabolismo , FN-kappa B/metabolismo , Osteosarcoma , Fosforilación , Fosfotirosina/metabolismo , Pruebas de Precipitina , Unión Proteica , Receptores de Interleucina-1/química , Receptores Tipo I de Interleucina-1 , Activación Transcripcional , Transfección , Células Tumorales Cultivadas , Tirosina/metabolismo , Dominios Homologos src/fisiologíaRESUMEN
Elucidation of the pathophysiology of Emery-Dreifuss muscular dystrophy, caused by mutations in emerin or lamin A/C, will require deciphering the role of these proteins in the functional organization of the nuclear envelope. This review focuses on nuclear envelope related mechanisms that modulate chromatin arrangement and control of gene transcription, both potential targets of the disease process in Emery-Dreifuss muscular dystrophy. Interactions of these proteins with chromatin- and nuclear matrix-associated proteins are now of particular interest, since chromatin alterations occur in cells in Emery-Dreifuss muscular dystrophy. Both emerin and lamin A/C interact with nuclear actin, a component of the chromatin remodeling complex associated with the nuclear matrix, suggesting that either chromatin arrangement, or gene transcription, or both, might be impaired in the disease.
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Núcleo Celular/fisiología , Cromatina/genética , Distrofia Muscular de Emery-Dreifuss/fisiopatología , Animales , Núcleo Celular/metabolismo , Expresión Génica , Humanos , Proteínas de la Membrana/genética , Distrofia Muscular de Emery-Dreifuss/genética , Distrofia Muscular de Emery-Dreifuss/metabolismo , Membrana Nuclear/metabolismo , Membrana Nuclear/fisiología , Matriz Nuclear/metabolismo , Matriz Nuclear/fisiología , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Transducción de Señal/genética , Transducción de Señal/fisiología , Transcripción Genética , Cromosoma XRESUMEN
Emerin, the protein whose production is altered in the X-linked form of Emery-Dreifuss muscular distrophy, has been hypothesized to be associated with the nuclear matrix on the basis of biochemical studies. In addition, immunocytochemical data reported its localization at the nuclear periphery, on the nuclear lamina, in sections of several normal tissues. We investigated the association of emerin with the nuclear matrix, by using cultured cells (SaOS-2, MG63 and HeLa-S3) and their in situ extracted matrix as a model, and immunocytochemical methods, both at the light and electron microscope level. Our results show a normal presence of emerin in the cultured cells and the specific persistence of emerin on the lamina of the in situ extracted nuclear matrix. This suggests a tight binding between emerin and the nuclear lamina independently from the interactions between the C-terminal hydrophobic domain of the protein and the inner nuclear membrane.
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Núcleo Celular/metabolismo , Proteínas de la Membrana/metabolismo , Distrofias Musculares/metabolismo , Timopoyetinas/metabolismo , Núcleo Celular/ultraestructura , Células Cultivadas , Técnica del Anticuerpo Fluorescente Directa , Células HeLa , Humanos , Inmunohistoquímica , Proteínas de la Membrana/genética , Microscopía Electrónica , Distrofias Musculares/genética , Distrofias Musculares/patología , Proteínas Nucleares , Timopoyetinas/genéticaRESUMEN
Emery-Dreifuss muscular dystrophy (EMD) is an inherited myopathy characterised by muscle contractures, progressive muscle wasting and weakness, with humeroperoneal distribution. Cardiac arrhythmia and heart conduction block are also important characteristics of this disease. The X-linked form of EMD is caused by the absence of emerin, encoded by the STA gene (Xq28). Emerin is normally localized in muscle and other tissues at the nuclear rim. Currently, muscle and skin biopsies are used for the immunohistochemical diagnosis. We demonstrate that emerin is present in the cheek oral mucosa, in the exfoliating epithelial cells, and we propose the collection of these cells as a new method for the diagnosis of X-linked EMD patients and the detection of carriers by immunofluorescence techniques: smears from healthy subjects contained about 98% emerin-positive cells, those from X-linked EMD patients contained none and those from carriers contained about 45%. The technique is completely non-invasive, simple, repeatable and inexpensive.
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Tamización de Portadores Genéticos , Ligamiento Genético , Mucosa Bucal/patología , Distrofias Musculares/genética , Cromosoma X , Adolescente , Adulto , Estudios de Casos y Controles , Mejilla , Niño , Citodiagnóstico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Distrofias Musculares/patología , Distrofia Muscular de Emery-DreifussRESUMEN
Phosphatidylinositol 4,5-bisphosphate (PIP2) is a key element of signal transduction, being the preferential substrate of specific phospholipases that produce second messengers such as inositol trisphosphate (IP3) and diacylglycerol (DG). Because PIP2 has been cytochemically identified by monoclonal antibodies not only in the cytoplasmic membranes but also in the nuclear envelope and within the nucleus, we performed a study by immunoblotting and by confocal and electron microscopic immunocytochemistry to identify the nuclear sites of PIP2 localization and to exclude any cross-reactivity of the antibody with other nuclear molecules. The results confirm the specificity of the immunolabeling and indicate that PIP2 is localized at precise intranuclear sites both in in situ and in isolated nuclei. They also show that a significant amount of the phospholipid is retained by the cytoskeleton and by the inner nuclear matrix in in situ matrix preparations. Moreover the sensitivity of the immunocytochemical reaction is capable of detecting quantitative variations of PIP2 nuclear content induced by agonists that modulate the signal transduction system at the nuclear level.
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Núcleo Celular/química , Fosfotransferasas (Aceptor de Grupo Alcohol)/análisis , Células 3T3 , Animales , Reacciones Cruzadas , Histonas/inmunología , Immunoblotting , Ratones , Microscopía Confocal , Microscopía Inmunoelectrónica , Matriz Nuclear/química , Fosfotransferasas (Aceptor de Grupo Alcohol)/inmunología , Pruebas de Precipitina , Células Tumorales CultivadasRESUMEN
OBJECTIVE: Leptin. a protein secreted by white adipocytes, plays a relevant role in the regulation of body weight and food intake. A possible role for sex hormones in the regulation of leptin secretion has been suggested; however, the effect of variations in oestrogen concentration on serum leptin levels has not been described so far. METHODS: In study 1, serum leptin concentrations were measured on days 3, 10, 17 and 24 of the menstrual cycle in 18 healthy, lean, regularly menstruating women, aged 18-35 years. Serum oestradiol, progesterone, testosterone. Delta4-androstenedione, dehydroepiandrosterone sulphate (DHEAS). LH and FSH concentrations were also determined. In study 2, serum leptin and oestradiol levels were measured on the 5th and 7th day of ovarian stimulation with human FSH (225 IU daily) during an in vitro fertilisation programme for infertility in 20 women aged 25-45 years. RESULTS: The results from study 1 show a physiological fluctuation of leptin levels during the menstrual cycle, which has not been described previously. Leptin levels are significantly lower in the early follicular phase. The results of study 2 show a parallel increase in serum oestrogen and leptin concentrations during FSH administration. CONCLUSIONS: The fluctuation in leptin levels during the menstrual cycle observed in study 1 is compatible with the hypothesis of a stimulatory effect of oestrogen on leptin secretion. The results of study 2 support the hypothesis of a relevant role for oestrogen in the regulation of leptin secretion. Leptin fluctuations during the menstrual cycle are consistent with reported perimenstrual variations in food craving and consumption.
Asunto(s)
Estrógenos/sangre , Proteínas/metabolismo , Adolescente , Adulto , Estrógenos/metabolismo , Femenino , Hormona Folículo Estimulante/administración & dosificación , Humanos , Inyecciones Intramusculares , Leptina , Ciclo Menstrual/sangre , Ciclo Menstrual/efectos de los fármacos , Persona de Mediana Edad , Obesidad/sangre , Progesterona/sangre , Progesterona/metabolismo , Proteínas/efectos de los fármacosRESUMEN
STUDY OBJECTIVE: To review the clinical and laboratory findings in a large number of patients with pneumococcal bacteremia in the 1980s and identify risk factors associated with increased mortality. DESIGN: Retrospective review of medical records identified by blood culture logbooks and ICD-9 codes. SETTING: Three community teaching hospitals affiliated with a medical school in northeastern Ohio. PATIENTS: 385 inpatients with pneumococcal bacteremia admitted between Jan 1, 1980 and Dec 31, 1989. MEASUREMENTS: Important clinical and laboratory information was abstracted from patients' medical records, compiled, computerized, and analyzed. MAIN RESULTS: The patients' mean age was 48 years. The overall mortality was 25 percent. The mortality increased with age, reaching 42 percent in patients over 65 years old. For these elderly patients, the mortality was higher (55 percent) for patients admitted from nursing homes than patients from the community (36 percent). Higher mortality was also associated with congestive heart failure (p = 0.001), alcoholism/cirrhosis (p = 0.02), diabetes mellitus (p = 0.05), and malignancy (p = 0.02). A platelet count less than 150,000/mm3, renal dysfunction (serum creatinine > 2 mg/dl), and the number of lobes involved were also associated with mortality. Patients receiving standard therapy (penicillin, ampicillin, erythromycin, or cephalosporins) had lower mortality. Of the previously specified risk factors for mortality, only age, whether standard therapy was administered, the number of lobes involved, and the serum creatinine level proved to be independent risk factors according to logistic regression. CONCLUSIONS: The overall mortality from pneumococcal bacteremia has not decreased during the past 40 years. Risk factors associated with increased mortality were identified. Prevention by immunization with polyvalent pneumococcal polysaccharide vaccine should be practiced more widely.
Asunto(s)
Bacteriemia , Infecciones Neumocócicas , Adolescente , Adulto , Anciano , Bacteriemia/complicaciones , Bacteriemia/microbiología , Bacteriemia/mortalidad , Bacteriemia/terapia , Niño , Preescolar , Femenino , Hospitalización , Hospitales Comunitarios , Hospitales de Enseñanza , Humanos , Lactante , Masculino , Infecciones Neumocócicas/complicaciones , Infecciones Neumocócicas/mortalidad , Infecciones Neumocócicas/terapia , Análisis de Regresión , Estudios Retrospectivos , Factores de Riesgo , Tasa de SupervivenciaRESUMEN
A five-year review (1979 to 1983) of 41 patients with active tuberculosis at the time of death was performed to determine the cause of death. Twenty deaths (49 percent) were directly attributed to tuberculosis. Overwhelming tuberculous disease was the cause of death for seven patients, and among them the majority had strikingly low serum levels of albumin. Ten patients died of either massive hemoptysis or respiratory failure. Only two patients died due to progressive drug-resistant disease in an area where drug resistance is common. The majority of patients (21/41; 51 percent) died of common medical problems unrelated to tuberculosis. Eleven patients died from cardiopulmonary disease (five pulmonary emboli, one respiratory failure due to chronic obstructive pulmonary disease, two acute myocardial infarctions, and two primary dysrhythmias). Three deaths were the result of gastrointestinal bleeding, and three patients died as a result of bacterial superinfection. Our data indicate that patients still die of tuberculosis in the era of effective antituberculosis therapy. It is imperative that clinicians are aware that pulmonary emboli, arteriosclerotic heart disease, bacterial superinfection, and gastrointestinal bleeding cause approximately 50 percent of the deaths among patients who have tuberculosis and that prompt recognition and treatment of those diseases might decrease the mortality from tuberculosis.