RESUMEN
Objective: To explore the value of optical coherence tomography (OCT) imaging system in evaluating cervical lesions in vivo. Methods: A total of 1 214 patients with cervical lesions were collected from January 2020 to December 2021 in the Third Affiliated Hospital of Zhengzhou University, Maternal and Chlid Heaith Hospital of Gushi County, Xinyang City, Henan Province, and Maternal and Chlid Heaith Hospital of Sui County, Shangqiu City, Henan Province. The age of the patients was (38.9±10.5) years (range: 16-77 years). All patients underwent in vivo cervical OCT examination and cervical biopsy pathology examination, and summarized the OCT image features of in vivo cervical lesions. Using the pathological diagnosis as the "gold standard", the accuracy, specificity, sensitivity, positive predictive value (PPV) and negative predictive value (NPV) of OCT image interpretation results were evaluated, as well as the consistency of OCT image diagnosis and pathological diagnosis. At the same time, the in vivo cervical OCT imaging system, as a newly developed screening tool, was compared with the traditional combined screening of human papillomavirus (HPV) and Thinprep cytologic test (TCT), to assess the screening effect. Results: By comparing the OCT images of the cervix in vivo with the corresponding HE images, the OCT image characteristics of the normal cervix and various types of cervical lesions in vivo were summarized. The accuracy, sensitivity, specificity, PPV and NPV of OCT image in the diagnosis of high-grade squamous intraepithelial lesion (HSIL) and above (HSIL+) were 93.4%, 88.5%, 95.0%, 85.0% and 96.2%, respectively. The accuracy, sensitivity, specificity, PPV and NPV of OCT for low-grade squamous intraepithelial lesion (LSIL) were 84.7%, 61.7%, 96.3%, 89.3% and 83.2%, respectively. The consistency between OCT image diagnosis and pathological diagnosis was strong (Kappa value was 0.701).The accuracy, sensitivity and specificity of OCT screening, HPV and TCT combined screening were 83.7% vs 64.9% (χ²=128.82, P<0.001), 77.8% vs 64.5% (χ²=39.01, P<0.001), 91.8% vs 65.4% (χ²=98.12, P<0.001), respectively. The differences were statistically significant. Conclusions: OCT imaging system has high sensitivity and specificity in the evaluation of cervical lesions in vivo, and has the characteristics of non-invasive, real-time and high efficiency. OCT examination is expected to become an effective method for the diagnosis of cervical lesions and cervical cancer screening.
Asunto(s)
Cuello del Útero , Sensibilidad y Especificidad , Tomografía de Coherencia Óptica , Neoplasias del Cuello Uterino , Humanos , Femenino , Tomografía de Coherencia Óptica/métodos , Adulto , Neoplasias del Cuello Uterino/diagnóstico por imagen , Neoplasias del Cuello Uterino/patología , Neoplasias del Cuello Uterino/diagnóstico , Persona de Mediana Edad , Cuello del Útero/diagnóstico por imagen , Cuello del Útero/patología , Adolescente , Anciano , Displasia del Cuello del Útero/diagnóstico por imagen , Displasia del Cuello del Útero/patología , Displasia del Cuello del Útero/diagnóstico , Infecciones por Papillomavirus/diagnóstico , Adulto Joven , Frotis Vaginal , Biopsia , Valor Predictivo de las Pruebas , Detección Precoz del Cáncer/métodosRESUMEN
Objective: To investigate the morphological features, diagnosis and differential diagnosis of extrapleural sarcomatoid malignant mesothelioma (SMM). Methods: Six cases of extrapleural SMM were evaluated for their clinical, histological, immunohistochemical features, and prognosis. Results: Patients included 3 men and 3 women, with a median age of 60 years (range 41-75 years). All patients had no asbestos exposure in history and no pleural lesions. The tumors involved peritoneum (3 cases), bone (2 cases), and neck soft tissue (1 case). Histologically, the tumors were mainly composed of slender to plump spindle cells with occasional polymorphic cells, arranged in fascicular to storiform pattern or haphazardly organized, closely resembling those of fibromatosis, fibrosarcoma or malignant fibrous histiocytoma. The tumor cells were imunohistochemically positive for cytokeratin (pan, 6/6), calretinin (5/6), podoplanin (6/6), D2-40 (4/6), vimentin (6/6), WT1 (4/6), CD10 (3/6), SMA (4/6), and variably positive for CK7, and CK8/18, but were negative for other linage-specific markers. The Ki-67 proliferation indexes ranged from 25% to 55%, consistent with the diagnosis of malignant mesothelioma of the sarcomatous type. Ultrastructurally, the tumor cells possessed discontinuous external lamina, cytoplasmic processes, microfilaments and desmosomal intercellular junctions. Local recurrence or metastasis was seen in 1 case and 4 cases, respectively, after surgery, and all the patients died of the disease within 9 months. Conclusions: Extrapleural SMM, although rare, should be considered as a differential diagnosis among other benign or malignant sarcomatoid tumors and sarcomas. Along with clinical and radiological presentation, the combination of broad-spectrum cytokeratin, vimentin, and a series of mesothelial markers are useful for diagnosis of SMM.
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Neoplasias Óseas/patología , Neoplasias de Cabeza y Cuello/patología , Mesotelioma/patología , Neoplasias Peritoneales/patología , Adulto , Anciano , Biomarcadores de Tumor/análisis , Neoplasias Óseas/química , Calbindina 2/análisis , Diagnóstico Diferencial , Femenino , Fibrosarcoma/patología , Neoplasias de Cabeza y Cuello/química , Humanos , Inmunohistoquímica , Queratinas/análisis , Masculino , Mesotelioma/química , Mesotelioma/diagnóstico , Persona de Mediana Edad , Recurrencia Local de Neoplasia , Neoplasias Peritoneales/química , Pronóstico , Sarcoma/patología , Vimentina/análisisRESUMEN
Primary ovarian carcinoid tumors are rare entities, they may appear with other teratomatous components, and can be often being mistaken as part of mature cystic teratomas. Consistent with their rarity and low incidence, imaging clues that could have led to suspicion of this tumor are not well-documented. Herein, the authors present a rare case of primary ovarian carcinoid tumor in a mature cystic teratoma, who initially presented with complaints of abdominal distension for months. Contrast-enhanced computerized tomography (CT) demonstrated a multilobular mass with different density components including fat, soft tissue, and calcification materials, as well as rich vascular supply from the right ovarian vein. Serum tumor markers were within normal limits. Bilateral salpingo-oophorectomy was performed and the pathological diagnosis was mature cystic teratoma with coexisting primary ovarian carcinoid tumor, insular type. The patient has remained well with no residual disease for over one year of follow-up.
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Tumor Carcinoide/diagnóstico , Neoplasias Primarias Múltiples/diagnóstico , Neoplasias Ováricas/diagnóstico , Teratoma/diagnóstico , Anciano , Tumor Carcinoide/patología , Femenino , Humanos , Neoplasias Primarias Múltiples/patología , Neoplasias Ováricas/patología , Teratoma/patologíaRESUMEN
BACKGROUND: In addition to lipid lowering, further pleotropic effects of statins have been postulated. We aimed to study if the various pleotropic effects are due indirectly to the modulation of adipocytokines. MATERIALS AND METHODS: We studied the effect of atorvastatin on insulin sensitivity and the plasma adiponectin and leptin concentrations. Our randomized open labeled study had 29 hyperlipidemic Type 2 diabetic patients (14 females, 15 males, mean age 60.0+/-2.2 yr). They were randomized into three 12-week atorvastatin intervention types. Each day patients were given either 10 mg (no.=10), 20 mg (no.=10) or 40 mg (no.=9). Evaluations were performed before and after intervention. RESULTS: All baseline characteristics were statistically identical in the 3 groups. Drop in total cholesterol, LDL-cholesterol, and triglyceride levels were measured at the end. With 10 mg the drop was 30%, 37%, and 30%. The 20 mg group was 43%, 54%, and 34%. The 40 mg group was 42%, 51%, and 27%. Groups had no significant change of body mass index, HDLcholesterol, and glycated hemoglobin levels. Also, levels of insulin, adiponectin, leptin, homeostasis model assessment index (HOMA) and Quantitative Insulin Sensitivity Check Index (QUICKI) stayed the same. Pooled parameters of all 29 patients showed no difference in levels of insulin, adiponectin, leptin, HOMA, and QUICKI before and after treatment. CONCLUSIONS: Atorvstatin does not affect insulin sensitivity and the adiponectin or leptin levels in hyperlipidemic Type 2 diabetes.
Asunto(s)
Adiponectina/sangre , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Ácidos Heptanoicos/farmacología , Ácidos Heptanoicos/uso terapéutico , Hiperlipidemias/tratamiento farmacológico , Resistencia a la Insulina , Leptina/sangre , Pirroles/farmacología , Pirroles/uso terapéutico , Anciano , Anticolesterolemiantes/farmacología , Anticolesterolemiantes/uso terapéutico , Atorvastatina , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/complicaciones , Relación Dosis-Respuesta a Droga , Femenino , Hemoglobina Glucada/análisis , Ácidos Heptanoicos/administración & dosificación , Humanos , Hiperlipidemias/sangre , Hiperlipidemias/complicaciones , Masculino , Persona de Mediana Edad , Pirroles/administración & dosificaciónRESUMEN
BACKGROUNDS AND AIMS: Endoscopic sphincterotomy is a widely accepted treatment for patients with common bile duct stones. Despite improvement in this technique, endoscopic sphincterotomy is still associated with some biliary complications. Endoscopic balloon dilatation is a less traumatic and sphincter preserving method for removal of common bile duct stones. However, the results of controlled studies in comparison with these two methods are contradictory. The aim of this study is to compare the safety and efficacy of endoscopic balloon dilatation and endoscopic sphincterotomy in Chinese patients. PATIENTS AND METHODS: A total of 104 patients with common bile duct stones on endoscopic retrograde cholangiopancreatography were enrolled. They were randomly assigned to endoscopic balloon dilatation or endoscopic sphincterotomy. Endoscopic balloon dilatation was performed by using a balloon dilator to dilate the sphincter for 5 min. The common bile duct stones were then removed by a Dormia basket after endoscopic balloon dilatation or endoscopic sphincterotomy. Mechanical lithotripsy was performed if the stones were difficult to remove by Dormia basket. After discharge, patients were regularly followed up for biliary complications. RESULTS: The successful bile duct stone clearance rate was 94.1% in endoscopic balloon dilatation group and 100% in endoscopic sphincterotomy group. Post-procedural significant haemorrhage was higher in endoscopic sphincterotomy group than in endoscopic balloon dilatation group (14/53 versus 1/48, P < 0.001). The bleeding patient from endoscopic balloon dilatation group was a case of uremia and bleeding occurred 48 h after endoscopic balloon dilatation. All the patients with post-procedural haemorrhage were controlled endoscopically. The post-procedural serum amylase level showed no significant difference in both groups and none of them developed clinical pancreatitis. After a mean 16 months follow-up, three patients (6.3%) in endoscopic balloon dilatation group and four patients (7.5%) in endoscopic sphincterotomy group developed recurrent common bile duct stones. The recurrent common bile duct stones were multiple and muddy in consistency. They were successfully removed endoscopically. CONCLUSION: Both endoscopic balloon dilatation and endoscopic sphincterotomy are safe and effective techniques for the treatment of common bile duct stones. Endoscopic balloon dilatation can be safely applied in patients with coagulopathy and does not increase the incidence of pancreatitis or bleeding.
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Cateterismo , Colangiopancreatografia Retrógrada Endoscópica , Cálculos Biliares/terapia , Esfinterotomía Endoscópica , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Cálculos Biliares/cirugía , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Recurrencia , Resultado del TratamientoRESUMEN
Critical issues in apoptosis include the importance of caspases versus organelle dysfunction, dominance of anti- versus proapoptotic BCL-2 members, and whether commitment occurs upstream or downstream of mitochondria. Here, we show cells deficient for the downstream effectors Apaf-1, Caspase-9, or Caspase-3 display only transient protection from "BH3 domain-only" molecules and die a caspase-independent death by mitochondrial dysfunction. Cells with an upstream defect, lacking "multidomain" BAX, BAK demonstrate long-term resistance to all BH3 domain-only members, including BAD, BIM, and NOXA. Comparison of wild-type versus mutant BCL-2, BCL-X(L) indicates these antiapoptotics sequester BH3 domain-only molecules in stable mitochondrial complexes, preventing the activation of BAX, BAK. Thus, in mammals, BH3 domain-only molecules activate multidomain proapoptotic members to trigger a mitochondrial pathway, which both releases cytochrome c to activate caspases and initiates caspase-independent mitochondrial dysfunction.
Asunto(s)
Apoptosis/fisiología , Mitocondrias/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Animales , Proteínas Reguladoras de la Apoptosis , Factor Apoptótico 1 Activador de Proteasas , Proteína Proapoptótica que Interacciona Mediante Dominios BH3 , Proteína 11 Similar a Bcl2 , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Caspasas/genética , Caspasas/metabolismo , Línea Celular , Grupo Citocromo c/metabolismo , Precursores Enzimáticos/genética , Precursores Enzimáticos/metabolismo , Immunoblotting , Proteínas de la Membrana/metabolismo , Estructura Terciaria de Proteína , Proteínas/genética , Proteínas/metabolismo , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteína Destructora del Antagonista Homólogo bcl-2 , Proteína X Asociada a bcl-2 , Proteína Letal Asociada a bcl , Proteína bcl-XRESUMEN
Multiple death signals influence mitochondria during apoptosis, yet the critical initiating event for mitochondrial dysfunction in vivo has been unclear. tBID, the caspase-activated form of a "BH3-domain-only" BCL-2 family member, triggers the homooligomerization of "multidomain" conserved proapoptotic family members BAK or BAX, resulting in the release of cytochrome c from mitochondria. We find that cells lacking both Bax and Bak, but not cells lacking only one of these components, are completely resistant to tBID-induced cytochrome c release and apoptosis. Moreover, doubly deficient cells are resistant to multiple apoptotic stimuli that act through disruption of mitochondrial function: staurosporine, ultraviolet radiation, growth factor deprivation, etoposide, and the endoplasmic reticulum stress stimuli thapsigargin and tunicamycin. Thus, activation of a "multidomain" proapoptotic member, BAX or BAK, appears to be an essential gateway to mitochondrial dysfunction required for cell death in response to diverse stimuli.
Asunto(s)
Apoptosis/fisiología , Proteínas de la Membrana/metabolismo , Mitocondrias/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2 , Proteínas Proto-Oncogénicas/metabolismo , Animales , Anticuerpos , Proteína Proapoptótica que Interacciona Mediante Dominios BH3 , Biopolímeros , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Células Cultivadas , Grupo Citocromo c/metabolismo , Retículo Endoplásmico/metabolismo , Etopósido/farmacología , Hepatocitos/citología , Hepatocitos/metabolismo , Membranas Intracelulares/metabolismo , Proteínas de la Membrana/genética , Ratones , Estructura Terciaria de Proteína , Proteínas Proto-Oncogénicas/genética , Transducción de Señal , Estaurosporina/farmacología , Transfección , Rayos Ultravioleta , Proteína Destructora del Antagonista Homólogo bcl-2 , Proteína X Asociada a bcl-2 , Receptor fas/inmunología , Receptor fas/fisiologíaRESUMEN
Multiple apoptotic pathways release cytochrome c from the mitochondrial intermembrane space, resulting in the activation of downstream caspases. In vivo activation of Fas (CD95) resulted in increased permeability of the mitochondrial outer membrane and depletion of cytochrome c stores. Serial measurements of oxygen consumption, NADH redox state and membrane potential revealed a loss of respiratory state transitions. This tBID-induced respiratory failure did not require any caspase activity. At early time points, re-addition of exogenous cytochrome c markedly restored respiratory functions. Over time, however, mitochondria showed increasing irreversible respiratory dysfunction as well as diminished calcium buffering. Electron microscopy and tomographic reconstruction revealed asymmetric mitochondria with blebs of herniated matrix, distended inner membrane and partial loss of cristae structure. Thus, apoptogenic redistribution of cytochrome c is responsible for a distinct program of mitochondrial respiratory dysfunction, in addition to the activation of downstream caspases.
Asunto(s)
Apoptosis , Grupo Citocromo c/farmacología , Mitocondrias/efectos de los fármacos , Animales , Calcio/metabolismo , Femenino , Ratones , Ratones Endogámicos C57BL , Mitocondrias/enzimología , Mitocondrias/metabolismo , Transducción de Señal , Receptor fas/metabolismoRESUMEN
Many apoptotic molecules relocate subcellularly in cells undergoing apoptosis. The pro-apoptotic protein BID underwent posttranslational (rather than classic cotranslational) N-myristoylation when cleavage by caspase 8 caused exposure of a glycine residue. N-myristoylation enabled the targeting of a complex of p7 and myristoylated p15 fragments of BID to artificial membranes bearing the lipid composition of mitochondria, as well as to intact mitochondria. This post-proteolytic N-myristoylation serves as an activating switch, enhancing BID-induced release of cytochrome c and cell death.
Asunto(s)
Apoptosis , Proteínas Portadoras/metabolismo , Membranas Intracelulares/metabolismo , Mitocondrias/metabolismo , Ácido Mirístico/metabolismo , Aciltransferasas/genética , Aciltransferasas/metabolismo , Animales , Proteína Proapoptótica que Interacciona Mediante Dominios BH3 , Proteínas Portadoras/química , Caspasa 8 , Caspasa 9 , Caspasas/metabolismo , Grupo Citocromo c/metabolismo , Humanos , Células Jurkat , Liposomas/metabolismo , Ratones , Fragmentos de Péptidos/metabolismo , Conformación Proteica , Procesamiento Proteico-Postraduccional , Estructura Terciaria de Proteína , Transporte de Proteínas , Proteínas Recombinantes de Fusión/metabolismoRESUMEN
The presence of heavy metals (Cr, Cd, Pb and Zn) in feedstock increases the partitioning of polycyclic aromatic hydrocarbons (PAHs) in the solid as well as in the gaseous phases, which has been reported in our previous study. However, the partitioning of PAHs in air-pollution control equipment (APCE) has not been investigated thus far. Hence, the present work was conducted to study the partitioning of PAHs in APCE and the effect of heavy metals on PAHs formation by varying the target heavy metals in the feedstock.A fluidized bed incineration system which includes a primary combustion chamber (sand bed), a secondary combustion chamber (freeboard), and an APCE (cyclone and scrubber) was utilized in this study. The feedstock that contained various heavy metals was fed into the incinerator, and then the PAHs in the cyclone and scrubber were analyzed to determine the effect of heavy metals on PAHs partitioning. The results indicate that the presence of Pb and Zn in feedstock facilitates the formation of PAHs.
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Metales Pesados/farmacocinética , Hidrocarburos Policíclicos Aromáticos/farmacocinética , Incineración , Eliminación de Residuos/métodosRESUMEN
TNFR1/Fas engagement results in the cleavage of cytosolic BID to truncated tBID, which translocates to mitochondria. Immunodepletion and gene disruption indicate BID is required for cytochrome c release. Surprisingly, the three-dimensional structure of this BH3 domain-only molecule revealed two hydrophobic alpha-helices suggesting tBID itself might be a pore-forming protein. Instead, we demonstrate that tBID functions as a membrane-targeted death ligand in which an intact BH3 domain is required for cytochrome c release, but not for targeting. Bak-deficient mitochondria and blocking antibodies reveal tBID binds to its mitochondrial partner BAK to release cytochrome c, a process independent of permeability transition. Activated tBID results in an allosteric activation of BAK, inducing its intramembranous oligomerization into a proposed pore for cytochrome c efflux, integrating the pathway from death receptors to cell demise.
Asunto(s)
Proteínas Portadoras/metabolismo , Grupo Citocromo c/metabolismo , Proteínas de la Membrana/metabolismo , Regulación Alostérica , Animales , Proteína Proapoptótica que Interacciona Mediante Dominios BH3 , Biopolímeros , Membrana Celular/metabolismo , Ratones , Proteína Destructora del Antagonista Homólogo bcl-2RESUMEN
We review data supporting a model in which activated tBID results in an allosteric activation of BAK, inducing its intramembranous oligomerization into a proposed pore for cytochrome c efflux. The BH3 domain of tBID is not required for targeting but remains on the mitochondrial surface where it is required to trigger BAK to release cytochrome c. tBID functions not as a pore-forming protein but as a membrane targeted and concentrated death ligand. tBID induces oligomerization of BAK, and both Bid and Bak knockout mice indicate the importance of this event in the release of cytochrome c. In parallel, the full pro-apoptotic member BAX, which is highly homologous to BAK, rapidly forms pores in liposomes that release intravesicular FITC-cytochrome c approximately 20A. A definable pore progressed from approximately 11A consisting of two BAX molecules to a approximately 22A pore comprised of four BAX molecules, which transported cytochrome c. Thus, an activation cascade of pro-apoptotic proteins from BID to BAK or BAX integrates the pathway from surface death receptors to the irreversible efflux of cytochrome c. Cell Death and Differentiation (2000) 7, 1166 - 1173
Asunto(s)
Apoptosis/fisiología , Proteínas Portadoras/metabolismo , Grupo Citocromo c/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2 , Proteínas Proto-Oncogénicas/metabolismo , Transducción de Señal/fisiología , Animales , Proteína Proapoptótica que Interacciona Mediante Dominios BH3 , Humanos , Mitocondrias/metabolismo , Mitocondrias/ultraestructura , Proteína Destructora del Antagonista Homólogo bcl-2 , Proteína X Asociada a bcl-2RESUMEN
Progression of cells through the G1 phase of the cell cycle requires cyclin D:Cdk4/6 and cyclin E:Cdk2 complexes; however, the duration and ordering of these complexes remain unclear. To address this, we synthesized a peptidyl mimetic of the Cdk4/6 inhibitor, p16INK4a that contained an NH2-terminal TAT protein transduction domain. Transduction of TAT-p16 wild-type peptides into cells resulted in the loss of active, hypophosphorylated pRb and elicited an early G1 cell cycle arrest, provided cyclin E:Cdk2 complexes were inactive. We conclude that cyclin D:Cdk4/6 activity is required for early G1 phase cell cycle progression up to, but not beyond, activation of cyclin E:Cdk2 complexes at the restriction point and is thus nonredundant with cyclin E:Cdk2 in late G1.
Asunto(s)
Quinasas CDC2-CDC28 , Inhibidor p16 de la Quinasa Dependiente de Ciclina/fisiología , Quinasas Ciclina-Dependientes/fisiología , Ciclinas/fisiología , Fase G1/fisiología , Proteínas Serina-Treonina Quinasas/fisiología , Proteínas Proto-Oncogénicas , Proteína de Retinoblastoma/metabolismo , Línea Celular , Ciclina D , Ciclina E/fisiología , Quinasa 2 Dependiente de la Ciclina , Quinasa 4 Dependiente de la Ciclina , Quinasa 6 Dependiente de la Ciclina , Humanos , Queratinocitos , Fosforilación , TransfecciónRESUMEN
"BH3 domain only" members of the BCL-2 family including the pro-apoptotic molecule BID represent candidates to connect with proximal signal transduction. Tumor necrosis factor alpha (TNFalpha) treatment induced a caspase-mediated cleavage of cytosolic, inactive p22 BID at internal Asp sites to yield a major p15 and minor p13 and p11 fragments. p15 BID translocates to mitochondria as an integral membrane protein. p15 BID within cytosol targeted normal mitochondria and released cytochrome c. Immunodepletion of p15 BID prevents cytochrome c release. In vivo, anti-Fas Ab results in the appearance of p15 BID in the cytosol of hepatocytes which translocates to mitochondria where it releases cytochrome c. Addition of activated caspase-8 to normal cytosol generates p15 BID which is also required in this system for release of cytochrome c. In the presence of BCL-XL/BCL-2, TNFalpha still induced BID cleavage and p15 BID became an integral mitochondrial membrane protein. However, BCL-XL/BCL-2 prevented the release of cytochrome c, yet other aspects of mitochondrial dysfunction still transpired and cells died nonetheless. Thus, while BID appears to be required for the release of cytochrome c in the TNF death pathway, the release of cytochrome c may not be required for cell death.
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Proteínas Portadoras/metabolismo , Caspasas/metabolismo , Grupo Citocromo c/metabolismo , Mitocondrias/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Secuencia de Aminoácidos , Antígenos CD/metabolismo , Apoptosis , Proteína Proapoptótica que Interacciona Mediante Dominios BH3 , Proteínas Portadoras/química , Cicloheximida/farmacología , Citosol/metabolismo , Hidrólisis , Mitocondrias/efectos de los fármacos , Mitocondrias/enzimología , Datos de Secuencia Molecular , Receptores del Factor de Necrosis Tumoral/metabolismo , Receptores Tipo I de Factores de Necrosis Tumoral , Factor de Necrosis Tumoral alfa/farmacología , Proteína bcl-X , Receptor fas/metabolismoRESUMEN
Expression of the pro-apoptotic molecule BAX has been shown to induce cell death. While BAX forms both homo- and heterodimers, questions remain concerning its native conformation in vivo and which moiety is functionally active. Here we demonstrate that a physiologic death stimulus, the withdrawal of interleukin-3 (IL-3), resulted in the translocation of monomeric BAX from the cytosol to the mitochondria where it could be cross-linked as a BAX homodimer. In contrast, cells protected by BCL-2 demonstrated a block in this process in that BAX did not redistribute or homodimerize in response to a death signal. To test the functional consequence of BAX dimerization, we expressed a chimeric FKBP-BAX molecule. Enforced dimerization of FKBP-BAX by the bivalent ligand FK1012 resulted in its translocation to mitochondria and induced apoptosis. Caspases were activated yet caspase inhibitors did not block death; cytochrome c was not released detectably despite the induction of mitochondrial dysfunction. Moreover, enforced dimerization of BAX overrode the protection by BCL-XL and IL-3 to kill cells. These data support a model in which a death signal results in the activation of BAX. This conformational change in BAX manifests in its translocation, mitochondrial membrane insertion and homodimerization, and a program of mitochondrial dysfunction that results in cell death.
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Apoptosis/fisiología , Caspasas , Mitocondrias/fisiología , Proteínas Proto-Oncogénicas/química , Proteínas Proto-Oncogénicas/metabolismo , Clorometilcetonas de Aminoácidos/farmacología , Animales , Caspasa 3 , Caspasa 9 , Línea Celular , Cisteína Endopeptidasas/metabolismo , Inhibidores de Cisteína Proteinasa/farmacología , Citosol/metabolismo , Dimerización , Activación Enzimática , Humanos , Interleucina-3/fisiología , Ligandos , Potenciales de la Membrana , Ratones , Proteínas Proto-Oncogénicas c-bcl-2/fisiología , Ratas , Proteínas Recombinantes de Fusión , Tacrolimus/análogos & derivados , Tacrolimus/farmacología , Proteína X Asociada a bcl-2 , Proteína bcl-XRESUMEN
In cycling cells, the retinoblastoma protein (pRb) is un- and/or hypo-phosphorylated in early G1 and becomes hyper-phosphorylated in late G1. The role of hypo-phosphorylation and identity of the relevant kinase(s) remains unknown. We show here that hypo-phosphorylated pRb associates with E2F in vivo and is therefore active. Increasing the intracellular concentration of the Cdk4/6 specific inhibitor p15(INK4b) by transforming growth factor beta treatment of keratinocytes results in G1 arrest and loss of hypo-phosphorylated pRb with an increase in unphosphorylated pRb. Conversely, p15(INK4b)-independent transforming growth factor beta-mediated G1 arrest of hepatocellular carcinoma cells results in loss of Cdk2 kinase activity with continued Cdk6 kinase activity and pRb remains only hypo-phosphorylated. Introduction of the Cdk4/6 inhibitor p16(INK4a) protein into cells by fusion to a protein transduction domain also prevents pRb hypo-phosphorylation with an increase in unphosphorylated pRb. We conclude that cyclin D:Cdk4/6 complexes hypo-phosphorylate pRb in early G1 allowing continued E2F binding.
Asunto(s)
Proteínas de Ciclo Celular , Quinasas Ciclina-Dependientes/metabolismo , Ciclinas/metabolismo , Proteínas de Unión al ADN , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas , Proteína de Retinoblastoma/metabolismo , Proteínas Supresoras de Tumor , Proteínas Portadoras/metabolismo , Línea Celular , Ciclina D , Quinasa 4 Dependiente de la Ciclina , Quinasa 6 Dependiente de la Ciclina , Inhibidor p15 de las Quinasas Dependientes de la Ciclina , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , Factores de Transcripción E2F , Fase G1 , Humanos , Fosforilación , Proteína 1 de Unión a Retinoblastoma , Transducción de Señal , Factor de Transcripción DP1 , Factores de Transcripción/metabolismo , Factor de Crecimiento Transformador beta/farmacología , Células Tumorales CultivadasRESUMEN
BACKGROUND: Severe paraquat poisoning causes considerable morbidity and mortality. High doses of cyclophosphamide and dexamethasone have been used to treat patients with paraquat poisoning, but with mixed results. The use of pulse methylprednisolone and cyclophosphamide was investigated in the treatment of moderately severe paraquat poisoning. METHODS: During a six-year period 87 patients with paraquat poisoning were admitted to hospital, of whom 33 had moderate to severe intoxication. Seventeen patients received conventional treatment and served as historical controls, and 16 received intravenous infusions of cyclophosphamide 1 g daily for two days and methylprednisolone 1 g daily for three days. RESULTS: There were no differences between the groups in age, sex, severity of paraquat poisoning (as assessed by urine dithionite tests), or in the time elapsed from ingestion to presentation at hospital or to the beginning of haemoperfusion. No differences were seen in biochemical measurements on the third day after paraquat poisoning. The mortality in the pulse therapy group was lower than that in the control group (4/16 (25%) versus 12/17 (70.6%), p = 0.01). All fatalities were from progressive respiratory failure. CONCLUSIONS: Pulse therapy with cyclophosphamide and methylprednisolone may be effective in preventing respiratory failure and reducing mortality in patients with moderate to severe paraquat poisoning. Further controlled studies are needed to confirm this and to establish the mechanisms.
Asunto(s)
Antiinflamatorios/uso terapéutico , Antídotos/uso terapéutico , Ciclofosfamida/uso terapéutico , Metilprednisolona/uso terapéutico , Paraquat/envenenamiento , Adulto , Antiinflamatorios/administración & dosificación , Antiinflamatorios/efectos adversos , Antídotos/administración & dosificación , Antídotos/efectos adversos , Ciclofosfamida/administración & dosificación , Ciclofosfamida/efectos adversos , Quimioterapia Combinada , Femenino , Humanos , Masculino , Metilprednisolona/administración & dosificación , Metilprednisolona/efectos adversos , Intoxicación/tratamiento farmacológico , Intoxicación/mortalidad , Intoxicación/patologíaRESUMEN
Pulmonary siderosis is one kind of pneumoconiosis caused by the long term inhalation of iron dust. It occurs in a number of occupations including steel rolling and grinding, welding, polishing, casting, boiler scaling, iron ore mining and emery working. Here we report a case of pulmonary siderosis. A 49-year-old male who had worked in an iron foundry for 30 years was admitted because diffuse micronodular lesions were seen in both lung fields on a routine chest radiographic study. A pulmonary function test disclosed a mildly restrictive ventilatory defect. Transbronchial lung biopsy revealed a significant amount of iron dust deposited within a fibrous nodule by which confirmed the diagnosis of pulmonary siderosis.