RESUMO
AIMS: To test the hypothesis that 1-h plasma glucose in an oral glucose tolerance test is a better predictor of the development of diabetes than 2-h plasma glucose, independently of indices of insulin secretion or action in Japanese adults. METHODS: A historical cohort study was conducted in 1445 Japanese workers who did not have diabetes. The association between 1-h plasma glucose and the development of Type 2 diabetes was analysed. RESULTS: Overall, 95 of the study participants developed Type 2 diabetes during a mean follow-up of 4.5 years. The area under the receiver-operating characteristic curve for 1-h plasma glucose for future diabetes [0.88 (95% CI 0.84-0.91)] was greater than that for 2-h plasma glucose [0.79 (95% CI 0.74-0.84)], and for insulinogenic [0.73 (95% CI 0.68-0.78)] and disposition indices [0.79 (95% CI 0.74-0.84); P < 0.05]. Compared with the first quartile, the hazard ratio for future diabetes in the fourth quartile of 1-h plasma glucose was 42.5 [95% CI 5.7-315.2 (P < 0.05)] and the hazard ratio in the fourth quartile of 2-h plasma glucose was 4.4 [95% CI 1.8-10.8 (P < 0.05)], after adjustments for covariates including fasting plasma glucose. The significance of the elevated hazard ratio in the fourth quartile of 1-h plasma glucose was maintained after adjustments for 2-h plasma glucose, insulinogenic index or disposition index, whereas the elevation of the hazard ratio in the fourth quartile of 2-h plasma glucose was diminished and was no longer significant after adjustments for 1-h plasma glucose. CONCLUSIONS: One-hour plasma glucose had a greater association with the future development of Type 2 diabetes than did 2-h plasma glucose, independently of oral glucose tolerance test-derived indices of insulin action in a Japanese population.
Assuntos
Glicemia/análise , Diabetes Mellitus Tipo 2/diagnóstico , Estado Pré-Diabético/sangue , Estado Pré-Diabético/diagnóstico , Adulto , Povo Asiático , Estudos de Coortes , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/etnologia , Progressão da Doença , Feminino , Seguimentos , Intolerância à Glucose/sangue , Intolerância à Glucose/diagnóstico , Intolerância à Glucose/etnologia , Teste de Tolerância a Glucose/métodos , Humanos , Japão , Masculino , Estado Pré-Diabético/etnologia , Valor Preditivo dos Testes , Fatores de TempoRESUMO
BACKGROUND: Giant cell tumor of bone (GCTB) is a rare primary bone tumor, characterized by osteoclast-like giant cells that express receptor activator of nuclear factor-kappa B (RANK), and stromal cells that express RANK ligand (RANKL), a key mediator of osteoclast activation. A RANKL-specific inhibitor, denosumab, was predicted to reduce osteolysis and control disease progression in patients with GCTB. PATIENTS AND METHODS: Seventeen patients with GCTB were enrolled. Patients were treated with denosumab at 120 mg every 4 weeks, with a loading dose of 120 mg on days 8 and 15. To evaluate efficacy, objective tumor response was evaluated prospectively by an independent imaging facility on the basis of prespecified criteria. RESULTS: The proportion of patients with an objective tumor response was 88% based on best response using any tumor response criteria. The proportion of patients with an objective tumor response using individual response criteria was 35% based on the modified Response Evaluation Criteria in Solid Tumors (RECIST) criteria, 82% based on the modified European Organization for Research and Treatment of Cancer (EORTC) criteria, and 71% based on inverse Choi criteria. The median time of study treatment was 13.1 months. CONCLUSION: The findings demonstrate that denosumab has robust clinical efficacy in the treatment of GCTB.
Assuntos
Conservadores da Densidade Óssea/uso terapêutico , Neoplasias Ósseas/tratamento farmacológico , Denosumab/uso terapêutico , Tumor de Células Gigantes do Osso/tratamento farmacológico , Recidiva Local de Neoplasia/tratamento farmacológico , Adolescente , Adulto , Idoso , Neoplasias Ósseas/patologia , Feminino , Seguimentos , Tumor de Células Gigantes do Osso/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Estadiamento de Neoplasias , Prognóstico , Estudos Prospectivos , Adulto JovemRESUMO
SUMMARY: A 12-month extension phase of DIRECT in Japanese subjects with osteoporosis showed that total 3 years of denosumab treatment in Japanese postmenopausal women and men with osteoporosis was associated with low fracture rates, persistent bone turnover marker (BTM) reductions, continuous bone mineral density (BMD) increases, and a favorable overall benefit/risk profile. INTRODUCTION: The DIRECT trial demonstrated that 2 years of treatment with denosumab 60 mg subcutaneously every 6 months significantly reduced the incidence of vertebral fracture compared to placebo in Japanese postmenopausal women and men with osteoporosis. The purpose of this study is to evaluate the efficacy and safety of denosumab treatment for up to 3 years. METHODS: This study includes a 2-year randomized, double-blind, placebo-controlled phase and a 1-year open-label extension phase in which all subjects received denosumab. The data correspond to 3 years of denosumab treatment in subjects who received denosumab (long-term group) and 1 year of denosumab treatment in subjects who received placebo (cross-over group) in the double-blind phase. RESULTS: Eight hundred and ten subjects who completed the double-blind phase enrolled into the extension phase, and 775 subjects completed the study. All subjects received denosumab with daily supplements of calcium and vitamin D. The cumulative 36-month incidences of new or worsening vertebral fractures and new vertebral fractures were 3.8 and 2.5 %, respectively, in the long-term group. In this group, the BMD continued to increase, and the reduction in BTMs was maintained. In the cross-over group, comparable BMD increases and BTMs reductions to those of in their first year of the long-term group were confirmed. Adverse events did not show a notable increase with long-term denosumab administration. One event of osteonecrosis of the jaw occurred in the cross-over group. CONCLUSIONS: Three-year denosumab treatment in Japanese subjects with osteoporosis showed a favorable benefit/risk profile.
Assuntos
Conservadores da Densidade Óssea/administração & dosagem , Denosumab/administração & dosagem , Osteoporose/tratamento farmacológico , Fraturas por Osteoporose/prevenção & controle , Idoso , Biomarcadores/sangue , Densidade Óssea/efeitos dos fármacos , Conservadores da Densidade Óssea/efeitos adversos , Conservadores da Densidade Óssea/uso terapêutico , Remodelação Óssea/efeitos dos fármacos , Remodelação Óssea/fisiologia , Cálcio/uso terapêutico , Denosumab/efeitos adversos , Denosumab/uso terapêutico , Método Duplo-Cego , Esquema de Medicação , Quimioterapia Combinada , Feminino , Humanos , Injeções Subcutâneas , Masculino , Pessoa de Meia-Idade , Osteoporose/complicações , Osteoporose/fisiopatologia , Osteoporose Pós-Menopausa/complicações , Osteoporose Pós-Menopausa/tratamento farmacológico , Osteoporose Pós-Menopausa/fisiopatologia , Fraturas por Osteoporose/etiologia , Fraturas por Osteoporose/fisiopatologia , Fraturas da Coluna Vertebral/etiologia , Fraturas da Coluna Vertebral/fisiopatologia , Fraturas da Coluna Vertebral/prevenção & controle , Vitamina D/uso terapêuticoRESUMO
AIMS: Mineralocorticoid receptor (MR) blockade is an effective treatment for hypertension and diabetic nephropathy. There are no data on the effects of MR blockade on diabetic peripheral neuropathy (DPN). The aim of this study was to determine whether MRs are present in the peripheral nerves and to investigate the effectiveness of MR blockade on DPN in streptozotocin (STZ)-induced diabetic rats. METHODS: Expression of MR protein and messenger RNA (mRNA) was examined in the peripheral nerves using Western blot analysis and RT-PCR. We next studied the effects of the selective MR antagonist eplerenone and the angiotensin II receptor blocker candesartan on motor and sensory nerve conduction velocity (NCV), morphometric changes and cyclooxygenase-2 (COX-2) gene and NF-κB protein expression in the peripheral nerves of STZ-induced diabetic rats. RESULTS: Expression of MR protein and mRNA in peripheral nerves was equal to that in the kidney. Motor NCV was significantly improved by 8 weeks of treatment with either eplerenone (39.1 ± 1.2 m/s) or candesartan (46.4 ± 6.8 m/s) compared with control diabetic rats (33.7 ± 2.0 m/s) (p < 0.05). Sensory NCV was also improved by treatment with candesartan or eplerenone in diabetic rats. Eplerenone and candesartan caused significant improvement in mean myelin fibre area and mean myelin area compared with control diabetic rats (p < 0.05). COX-2 mRNA and NF-κB protein were significantly elevated in the peripheral nerves of diabetic rats compared with control rats, and treatment with eplerenone or candesartan reduced these changes in gene expression (p < 0.05). CONCLUSION: MR blockade may have neuroprotective effects on DPN.
Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Benzimidazóis/farmacologia , Diabetes Mellitus Experimental/tratamento farmacológico , Nefropatias Diabéticas/prevenção & controle , Antagonistas de Receptores de Mineralocorticoides , Nervos Periféricos/efeitos dos fármacos , Espironolactona/análogos & derivados , Tetrazóis/farmacologia , Animais , Compostos de Bifenilo , Western Blotting , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/fisiopatologia , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/fisiopatologia , Eplerenona , Masculino , Antagonistas de Receptores de Mineralocorticoides/farmacologia , NF-kappa B/metabolismo , Nervos Periféricos/fisiopatologia , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real , Receptores de Mineralocorticoides/genética , Receptores de Mineralocorticoides/metabolismo , Espironolactona/farmacologiaRESUMO
Missense mutations in the human presenilin-1 (PS1) gene, which is found on chromosome 14, cause early-onset familial Alzheimer's disease (FAD). FAD-linked PS1 variants alter proteolytic processing of the amyloid precursor protein and cause an increase in vulnerability to apoptosis induced by various cell stresses. However, the mechanisms responsible for these phenomena are not clear. Here we report that mutations in PS1 affect the unfolded-protein response (UPR), which responds to the increased amount of unfolded proteins that accumulate in the endoplasmic reticulum (ER) under conditions that cause ER stress. PS1 mutations also lead to decreased expression of GRP78/Bip, a molecular chaperone, present in the ER, that can enable protein folding. Interestingly, GRP78 levels are reduced in the brains of Alzheimer's disease patients. The downregulation of UPR signalling by PS1 mutations is caused by disturbed function of IRE1, which is the proximal sensor of conditions in the ER lumen. Overexpression of GRP78 in neuroblastoma cells bearing PS1 mutants almost completely restores resistance to ER stress to the level of cells expressing wild-type PS1. These results show that mutations in PS1 may increase vulnerability to ER stress by altering the UPR signalling pathway.
Assuntos
Retículo Endoplasmático/metabolismo , Proteínas de Choque Térmico , Proteínas de Membrana/metabolismo , Mutação/genética , Dobramento de Proteína , Transdução de Sinais , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Calcimicina/farmacologia , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Morte Celular/efeitos dos fármacos , Linhagem Celular , Retículo Endoplasmático/efeitos dos fármacos , Chaperona BiP do Retículo Endoplasmático , Endorribonucleases , Proteínas de Choque Térmico HSP70/metabolismo , Humanos , Membranas Intracelulares/metabolismo , Proteínas de Membrana/genética , Camundongos , Camundongos Transgênicos , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Neuroblastoma , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Fosforilação , Presenilina-1 , Ligação Proteica , Desnaturação Proteica , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transfecção , Tunicamicina/farmacologiaRESUMO
Osteoclast-activating factor (OAF), a powerful stimulator of osteoclastic bone resorption, is released by peripheral blood mononuclear cells on exposure to phytohemagglutinin (PHA) or a specific antigen to which the leukocytes have been previously exposed. Both lymphocytes and monocytes are required in the leukocyte population for OAF release to occur. In this study we examined the relationship between the lymphocyte and monocyte in OAF production. Biological activity, as a result of OAF, was assessed by a bioassay based on the release of previously incorporated 45Ca from fetal rodent long bones in organ culture. We found that an enriched lymphocyte population depleted of monocytes by serial adherence does not release OAF after stimulation with PHA, although the cells are activated as assessed by [3H]thymidine and 3H-amino acid incorporation. When conditioned media harvested from adherent cells which did not contain OAF was added to the enriched lymphocytes, OAF release occurred. Media harvested from adherent cells which were cultured with indomethacin (10 microM), an inhibitor of prostaglandin synthesis, did not permit OAF release by activated lymphocytes. When PGE1 and PGE2 (0.1 microM) were added exogenously to the enriched lymphocyte population, OAF release occurred after stimulation with PHA. These results indicate that, (a) the activated lymphocyte is the cell or origin of OAF, (b) prostaglandins produced by monocytes are necessary for OAF production by activated lymphocytes, and (c) monocyte prostaglandins can influence bone resorption indirectly by regulating OAF production as well as directly by osteoclast activation. The interactions of OAF and prostaglandins at bone resorbing sites may be important in inflammatory and neoplastic diseases associated with bone destruction.
Assuntos
Reabsorção Óssea , Monócitos/metabolismo , Prostaglandinas/biossíntese , Células Cultivadas , Humanos , Indometacina/farmacologia , Linfócitos/imunologia , Linfocinas , Monócitos/imunologia , Osteoclastos , Fito-HemaglutininasRESUMO
The production of osteoclast-activating factor (OAF) by normal human peripheral blood leukocytes stimulated by phytohemagglutinin was inhibited by a series of structurally unrelated inhibitors of prostaglandin synthetase. Inhibition of OAF production by these agents was reversed by adding prostaglandins of the E series back to the leukocyte suspension. These results indicate that prostaglandin synthesis is necessary for OAF production.
Assuntos
Reabsorção Óssea/efeitos dos fármacos , Inibidores de Ciclo-Oxigenase , Leucócitos/metabolismo , Linfocinas/biossíntese , Osteoclastos/efeitos dos fármacos , Prostaglandinas E/farmacologia , Ácido Flufenâmico/farmacologia , Humanos , Indometacina/farmacologia , Leucócitos/efeitos dos fármacos , Fito-Hemaglutininas/farmacologiaRESUMO
c-src deletion in mice leads to osteopetrosis as a result of reduced bone resorption due to an alteration of the osteoclast. We report that deletion/reduction of Src expression enhances osteoblast differentiation and bone formation, contributing to the increase in bone mass. Bone histomorphometry showed that bone formation was increased in Src null compared with wild-type mice. In vitro, alkaline phosphatase (ALP) activity and nodule mineralization were increased in primary calvarial cells and in SV40-immortalized osteoblasts from Src(-/-) relative to Src(+/+) mice. Src-antisense oligodeoxynucleotides (AS-src) reduced Src levels by approximately 60% and caused a similar increase in ALP activity and nodule mineralization in primary osteoblasts in vitro. Reduction in cell proliferation was observed in primary and immortalized Src(-/-) osteoblasts and in normal osteoblasts incubated with the AS-src. Semiquantitative reverse transcriptase-PCR revealed upregulation of ALP, Osf2/Cbfa1 transcription factor, PTH/PTHrP receptor, osteocalcin, and pro-alpha 2(I) collagen in Src-deficient osteoblasts. The expression of the bone matrix protein osteopontin remained unchanged. Based on these results, we conclude that the reduction of Src expression not only inhibits bone resorption, but also stimulates osteoblast differentiation and bone formation, suggesting that the osteogenic cells may contribute to the development of the osteopetrotic phenotype in Src-deficient mice.
Assuntos
Proteínas de Neoplasias , Osteoblastos/citologia , Osteogênese/genética , Proteínas Proto-Oncogênicas pp60(c-src)/genética , Fosfatase Alcalina/biossíntese , Animais , Reabsorção Óssea/genética , Diferenciação Celular , Divisão Celular , Células Cultivadas , Subunidade alfa 1 de Fator de Ligação ao Core , Regulação da Expressão Gênica/efeitos dos fármacos , Camundongos , Camundongos Mutantes , Oligonucleotídeos Antissenso/farmacologia , Osteopetrose/genética , Hormônio Paratireóideo/biossíntese , Fenótipo , Receptores de Hormônios Paratireóideos/biossíntese , Crânio/citologia , Fatores de Transcrição/biossíntese , Transcrição GênicaRESUMO
Osteoclasts are multinucleated cells of hemopoietic origin that are responsible for bone resorption during physiological bone remodeling and in a variety of bone diseases. Osteoclast development requires direct heterotypic cell-cell interactions of the hemopoietic osteoclast precursors with the neighboring osteoblast/stromal cells. However, the molecular mechanisms underlying these heterotypic interactions are poorly understood. We isolated cadherin-6 isoform, denoted cadherin-6/2 from a cDNA library of human osteoclast-like cells. The isolated cadherin-6/2 is 3,423 bp in size consisting of an open reading frame of 2,115 bp, which encodes 705 amino acids. This isoform lacks 85 amino acids between positions 333 and 418 and contains 9 different amino acids in the extracellular domain compared with the previously described cadherin-6. The human osteoclast-like cells also expressed another isoform denoted cadherin-6/1 together with the cadherin-6. Introduction of cadherin-6/2 into L-cells that showed no cell-cell contact caused evident morphological changes accompanied with tight cell-cell association, indicating the cadherin-6/2 we isolated here is functional. Moreover, expression of dominant-negative or antisense cadherin-6/2 construct in bone marrow-derived mouse stromal ST2 cells, which express only cadherin-6/2, markedly impaired their ability to support osteoclast formation in a mouse coculture model of osteoclastogenesis. Our results suggest that cadherin-6 may be a contributory molecule to the heterotypic interactions between the hemopoietic osteoclast cell lineage and osteoblast/bone marrow stromal cells required for the osteoclast differentiation. Since both osteoclasts and osteoblasts/bone marrow stromal cells are the primary cells controlling physiological bone remodeling, expression of cadherin-6 isoforms in these two cell types of different origin suggests a critical role of these molecules in the relationship of osteoclast precursors and cells of osteoblastic lineage within the bone microenvironment.
Assuntos
Caderinas/fisiologia , Osteoclastos/metabolismo , Células Estromais/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Caderinas/genética , Caderinas/metabolismo , Diferenciação Celular , Células Cultivadas , Clonagem Molecular , DNA Complementar , Expressão Gênica , Hematopoese , Humanos , Camundongos , Modelos Biológicos , Dados de Sequência Molecular , Oligonucleotídeos Antissenso , Conformação Proteica , RNA Mensageiro , Homologia de Sequência de AminoácidosRESUMO
An established line of mesenchymal cells from the human embryonic palate is highly sensitive to the stimulatory effect of epidermal growth factor on growth, labeled thymidine incorporation, and ornithine decarboxylase activity. The results suggest that epidermal growth factor may play a key role in development of various human embryonic and fetal tissues.
Assuntos
Fator de Crescimento Epidérmico/farmacologia , Palato/fisiologia , Peptídeos/farmacologia , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Replicação do DNA/efeitos dos fármacos , Embrião de Mamíferos , Feminino , Humanos , Insulina/farmacologia , Cinética , Especificidade de Órgãos , Ornitina Descarboxilase/metabolismo , Palato/efeitos dos fármacos , GravidezRESUMO
Dlx5 plays an important role in the embryonic development of mineralized tissues. We hypothesized that Dlx5 also functions in regulating post-natal bone formation in mice. To prove this hypothesis, we infected 5-day-old bone sialoprotein (BSP)/avian retroviral receptor gene (TVA) transgenic mice with replication-competent retroviral vectors expressing wild-type Dlx5 (RCAS-Dlx5WT) and mutated Dlx5 at arginine (R) 31 of its homeodomain (RCAS-Dlx5RH). Immunohistochemistry indicated that RCAS-Dlx5WT increased BSP and osteopontin (OPN) expression, whereas it decreased that of osteocalcin (OC). RCAS-Dlx5RH mediated opposite effects. Semi-quantitative RT-PCR confirmed these results. Ex vivo overexpression of RCAS-Dlx5WT in BSP/TVA calvarial cells promoted, whereas that of RCAS-Dlx5RH inhibited, mineralized nodule formation as compared with that in control cells. Our results suggest that Dlx5 promotes expression of early markers of osteogenic differentiation and increases mineralization post-natally.
Assuntos
Osso e Ossos/metabolismo , Proteínas de Homeodomínio/genética , Osteogênese/genética , Animais , Arginina/genética , Proteínas Aviárias/genética , Calcificação Fisiológica/genética , Proteínas da Matriz Extracelular/genética , Regulação da Expressão Gênica/genética , Vetores Genéticos/genética , Sialoproteína de Ligação à Integrina , Camundongos , Camundongos Transgênicos , Mutação/genética , Osteocalcina/genética , Osteopontina/genética , Fenótipo , Receptores Virais/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sialoglicoproteínas/genéticaRESUMO
Dendritic localization of the alpha subunit of Ca2+/calmodulin-dependent protein kinase II (alphaCaMKII) mRNA in CNS neurons requires its 3' untranslated region (3'UTR). We investigated this targeting mechanism by identifying two cis-acting elements in the 3'UTR. One is a 30-nucleotide element that mediated dendritic translocation. A homologous sequence in the 3'UTR of neurogranin, transcripts of which also reside in dendrites, also funtioned in cis to promote its dendritic transport. Other putative elements in the alphaCaMKII mRNA inhibit its transport in a resting state. This inhibition was removed in depolarized neurons, and such activity-dependent derepression was a primary requirement for their dendritic targeting.
Assuntos
Proteínas Quinases Dependentes de Cálcio-Calmodulina/genética , Proteínas de Ligação a Calmodulina/genética , Dendritos/genética , Proteínas do Tecido Nervoso/genética , RNA Mensageiro/genética , Animais , Sequência de Bases/genética , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina , Proteínas de Ligação a Calmodulina/metabolismo , Células Cultivadas , Clonagem Molecular/métodos , Dendritos/metabolismo , Embrião de Mamíferos , Perfilação da Expressão Gênica/métodos , Hipocampo , Memória/fisiologia , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/metabolismo , Neurogranina , Ratos , Ratos WistarRESUMO
BACKGROUND AND PURPOSE: Although the clinical importance of cortical microinfarcts has become well-recognized recently, the evolution of cortical microinfarcts on MR imaging is not fully understood. The aim of this study was to examine the temporal changes in acute cortical microinfarcts using susceptibility-weighted imaging and conventional MR imaging. MATERIALS AND METHODS: Patients with acute infarcts located in the cortical and/or juxtacortical region measuring ≤10 mm in axial diameter based on diffusion-weighted imaging who had a follow-up 3T MR imaging were retrospectively included in the study. All lesions did not show hypointensity on initial T2*WI. For cortical and/or juxtacortical microinfarcts detected on initial DWI, 2 neuroradiologists evaluated the follow-up MR imaging (T2WI, FLAIR, T2*WI, and SWI) and assessed lesion signal intensities and locations (cortical microinfarcts or microinfarcts with juxtacortical white matter involvement). RESULTS: On initial DWI, 2 radiologists observed 180 cortical and/or juxtacortical microinfarcts in 35 MR imaging examinations in 25 patients; on follow-up, the neuroradiologists identified 29 cortical microinfarcts (16%) on T2WI, 9 (5%) on FLAIR, 4 (2%) on T2*, and 97 (54%) on SWI. All cortical microinfarcts detected with any follow-up MR imaging showed hyperintensity on T2WI/FLAIR and/or hypointensity on T2*WI and SWI. CONCLUSIONS: SWI revealed conversion (paramagnetic susceptibility changes) of acute cortical microinfarcts, suggesting that a substantial number of cortical microinfarcts may contain hemorrhagic components.
Assuntos
Infarto Encefálico/diagnóstico por imagem , Infarto Encefálico/patologia , Adulto , Idoso , Feminino , Seguimentos , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Estudos RetrospectivosRESUMO
We previously demonstrated that human embryonic mesenchymal cells derived from the palate (HEMP cells) retain alkaline phosphatase (ALP) content and capacity for collagen synthesis after long-term culture, and their growth is markedly stimulated by epidermal growth factor (EGF). There was a dramatic decrease in ALP content and capacity to synthesize collagen in HEMP cells (HEMP-RV cells) persistently infected with rubella virus (RV). EGF increased ALP activity and decreased collagen synthesis in HEMP cells, whereas EGF showed no effect on these activities in HEMP-RV cells. Growth of HEMP-RV cells was slightly reduced compared with that of HEMP cells. EGF stimulated growth of HEMP cells and to a lesser extent of HEMP-RV cells. Binding of 125I-EGF to cell-surface receptors in HEMP-RV cells was, to our surprise, twice as much as that in HEMP cells. However, internalization of bound 125I-EGF in HEMP-RV cells was profoundly diminished. Thus, persistent RV infection causes not only changes in HEMP cell growth and differentiation but a decrease in or loss of HEMP cell responsiveness to EGF. The effects of persistent RV infection on palatal cell differentiation as well as growth may be responsible for the pathogenesis of congenital rubella. Furthermore, since HEMP cells appear to be closely related to osteoblasts, these results suggest a mechanism for RV-induced osseous abnormalities manifested in congenital rubella patients.
Assuntos
Fator de Crescimento Epidérmico/farmacologia , Palato/patologia , Rubéola (Sarampo Alemão)/patologia , Fosfatase Alcalina/análise , Desenvolvimento Ósseo , Diferenciação Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Células Cultivadas , Colágeno/biossíntese , Fator de Crescimento Epidérmico/metabolismo , Receptores ErbB , Humanos , Radioisótopos do Iodo , Palato/efeitos dos fármacos , Palato/embriologia , Receptores de Superfície Celular/análise , Rubéola (Sarampo Alemão)/congênitoRESUMO
Targeted disruption of the c-src proto-oncogene in mice has shown that src expression is required for normal bone resorption, since the src-deficient mutants develop osteopetrosis. To evaluate the mechanisms by which src-deficiency affects osteoclast function, we treated src-deficient mice with the stimulants of bone resorption, IL-1, parathyroid hormone, and parathyroid hormone-related protein, and analyzed the effects by quantitative bone histomorphometry and electron microscopy. Increased numbers of multinucleated cells with the morphological characteristics of osteoclasts appeared on bone surfaces, but these cells did not form ruffled borders or normal resorption lacunae. To confirm these in vivo findings, we cultured src-mutant bone marrow cells on dentine slices in the presence of 1,25 dihydroxyvitamin D3. Increased numbers of multinucleated cells were formed, but unlike normal murine bone marrow cells, they did not form resorption pits. These results indicate that osteoclasts appear in the absence of pp60c-src, but that pp60c-src expression is required for mature osteoclasts to form ruffled borders and resorb bone.
Assuntos
Reabsorção Óssea/etiologia , Osteoclastos/fisiologia , Proteínas Proto-Oncogênicas pp60(c-src)/fisiologia , Animais , Interleucina-1/farmacologia , Camundongos , Osteoclastos/efeitos dos fármacos , Hormônio Paratireóideo/farmacologia , Proteína Relacionada ao Hormônio Paratireóideo , Proteínas/farmacologiaRESUMO
A critical step in bone resorption is the fusion of mononuclear osteoclast precursors to form multinucleated osteoclasts. However, little is known of the molecular mechanisms that are responsible for this important process. Since the expression of proteins in the cadherin family of homophilic calcium-dependent cell adhesion molecules is involved in the fusion process for certain other cells, we examined their role in osteoclast formation. Immunohistochemical examination of human and mouse bone using monoclonal antibodies to human and mouse E-cadherin clearly demonstrated positive staining in osteoclasts. N- and P-cadherin were not detected. In cultures of murine marrow mononuclear cells in which osteoclasts form by cell fusion, E-cadherin expression determined by Western blotting reached the highest levels as fusion was taking place. Expression of E-cadherin gene fragment was also detected in the marrow cultures by polymerase chain reaction. To study the functional role of E-cadherin expression in osteoclastic differentiation, neutralizing monoclonal antibodies were examined for their effects on osteoclast formation. The antibodies decreased the number of tartrate-resistant acid phosphatase (a marker of murine osteoclast)-positive multinucleated cell (TRAP-positive MNC) by inhibiting the fusion of mononuclear osteoclast precursors, but not proliferation of these cells or their attachment to plastic dish surfaces. This inhibitory effect was reversible. Furthermore, synthetic peptides containing the cell adhesion recognition sequence of cadherins also decreased TRAP-positive MNC formation. The antibodies and peptides inhibited not only osteoclast formation but also bone resorption. Antibodies to other types of cadherins and control rat IgG had no effects in these culture systems. Our findings suggest that E-cadherin expression may be involved in fusion (differentiation) of hemopoietic osteoclast precursors into mature multinucleated osteoclasts.
Assuntos
Células da Medula Óssea , Caderinas/fisiologia , Osteoclastos/citologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais , Reabsorção Óssea , Calcitriol/farmacologia , Adesão Celular , Diferenciação Celular , Células Cultivadas , Humanos , Técnicas Imunoenzimáticas , Técnicas In Vitro , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Oligopeptídeos/químicaRESUMO
Recently, we have established a human squamous cell carcinoma of the maxilla (called MH-85) associated with hypercalcemia, leukocytosis, and cachexia in culture. MH-85 tumor cells caused the same paraneoplastic syndromes in tumor-bearing nude mice. We found that there was a sixfold increase in splenic size in MH-85 tumor-bearing mice. This increase paralleled tumor growth and was reversed by surgical removal of the tumor. Splenectomy in nude mice 1 wk before or 6 wk after tumor inoculation resulted in a decrease in tumor growth, and impairment of hypercalcemia, leukocytosis, and cachexia. In MH-85 tumor-bearing animals that had been pretreated by splenectomy, intravenous injection of fresh normal spleen cells caused an immediate reversal of leukocytosis, hypercalcemia, and cachexia. Since the presence of cachexia in both the patient and the mice carrying the tumor suggested tumor necrosis factor (TNF) may be overproduced, we injected polyclonal neutralizing antibodies raised against murine TNF into tumor-bearing mice. There was a rapid and reproducible decrease in blood ionized calcium, accompanied by suppression of osteoclast activity. No changes in blood ionized calcium were seen in mice injected with normal immune sera. In addition, there was an increase in body weight and decrease in white cell count. Plasma immunoreactive TNF was increased almost fourfold in tumor-bearing nude mice compared with control nude mice. Although TNF activity was undetectable in MH-85 culture supernatants, cells of the macrophage lineage, including spleen cells, released increased amounts of TNF when cultured with MH-85 tumor-conditioned media. These results suggest that splenic cytokines such as TNF may influence the development of the paraneoplastic syndromes of hypercalcemia, leukocytosis, and cachexia in these animals, as well as tumor growth. They also show that paraneoplastic syndromes may be due to factors produced by normal host cells stimulated by the presence of the tumor.
Assuntos
Caquexia/fisiopatologia , Carcinoma de Células Escamosas/fisiopatologia , Hipercalcemia/fisiopatologia , Leucocitose/fisiopatologia , Síndromes Paraneoplásicas/fisiopatologia , Fator de Necrose Tumoral alfa/fisiologia , Animais , Peso Corporal , Carcinoma de Células Escamosas/sangue , Humanos , Macrófagos/fisiologia , Camundongos , Camundongos Nus , Monócitos/fisiologia , Transplante de Neoplasias , Baço/fisiopatologia , Transplante HeterólogoRESUMO
Multiple steps are involved in the metastasis of cancer cells from primary sites to distant organs. These steps should be considered in the design of pharmacologic approaches to prevent or inhibit the metastatic process. In the present study, we have compared the effects of inhibiting several steps involved in the bone metastatic process individually with inhibition of both together. The steps we chose were matrix metalloproteinase (MMP) secretion, likely involved in tumor cell invasion, and osteoclastic bone resorption, the final step in the process. We used an experimental model in which inoculation of human estrogen-independent breast cancer MDA-231 cells into the left cardiac ventricle of female nude mice causes osteolytic lesions in bone. To inhibit cancer invasiveness, the tissue inhibitor of the MMP-2 (TIMP-2), which is a natural inhibitor of MMPs, was overexpressed in MDA-231 cells. To inhibit bone resorption, a potent bisphosphonate, ibandronate (4 microg/mouse) was daily administered subcutaneously. Nude mice received either; (a) nontransfected MDA-231 cells; (b) nontransfected MDA231 cells and ibandronate; (c) TIMP-2-transfected MDA-231 cells; or (d) TIMP-2-transfected MDA-231 cells and ibandronate. In mice from group a, radiographs revealed multiple osteolytic lesions. However, in mice from group b or group c, osteolytic lesions were markedly decreased. Of particular note, in animals from group d receiving both ibandronate and TIMP-2-transfected MDA-231 cells, there were no radiologically detectable osteolytic lesions. Survival rate was increased in mice of groups c and d. There was no difference in local enlargement in the mammary fat pad between nontransfected and TIMP-2-transfected MDA-231 cells. These results suggest that inhibition of both MMPs and osteoclastic bone resorption are more efficacious treatment for prevention of osteolytic lesions than either alone, and suggest that when therapies are designed based on the uniqueness of the bone microenvironment and combined with several common steps in the metastatic process, osteolytic bone metastases can be more efficiently and selectively inhibited.
Assuntos
Neoplasias Ósseas/prevenção & controle , Neoplasias Ósseas/secundário , Neoplasias da Mama/patologia , Difosfonatos/uso terapêutico , Osteólise/prevenção & controle , Biossíntese de Proteínas , Animais , Antineoplásicos , Reabsorção Óssea , Sobrevivência Celular/efeitos dos fármacos , Feminino , Terapia Genética , Ventrículos do Coração , Humanos , Ácido Ibandrônico , Camundongos , Camundongos Nus , Invasividade Neoplásica , Tíbia , Inibidor Tecidual de Metaloproteinase-2 , Transfecção , Transplante Heterólogo , Células Tumorais CultivadasRESUMO
Since absence of expression of the c-src gene product in mice indicates that the pp60c-src tyrosine kinase is required and essential for osteoclastic bone resorption, we tested the effects of the antibiotic herbimycin A, which is an inhibitor of pp60c-src on osteoclastic bone resorption in vitro and on hypercalcemia in vivo. We examined the effects of herbimycin A on the formation of bone resorbing osteoclasts in mouse long-term marrow cultures, on isolated rodent osteoclasts and on bone resorption in organ cultures of fetal rat long bones stimulated by parathyroid hormone. We found that herbimycin A in concentrations of 1-100 ng/ml inhibited bone resorption in each of these systems. We determined the effects of herbimycin A (100 ng/ml) on src tyrosine kinase activity in mouse marrow cultures and found that it was decreased. Herbimycin A also decreased elevated blood calcium levels that were induced either by repeated subcutaneous injections of recombinant human interleukin-1 alpha or by a human tumor. There was no evidence for toxicity in any of these culture systems or in mice treated with herbimycin A. A different tyrosine kinase inhibitor that does not inhibit pp60c-src was used as a control and caused none of these effects. These data suggest that pp60c-src tyrosine kinase inhibitors may be useful pharmacologic inhibitors of osteoclastic bone resorption and hypercalcemia.