RESUMEN
Case detection, diagnosis and treatment of tuberculosis 1 B) in children are challenging issues vorldwide. This study in Afghanistan aimed to evaluate paediatric TB case management, including contact investigation, at health facilities where all diagnostic processes were available. In 7 out of 8 regions of the country 1 province was selected. Documents used for management of paediatric TB cases were reviewed in 15 distinct hospitals and 8 provincial hospitals in the selected provinces. The key issues which emerged were: a low suspect rate among total outpatients (0.4%) and a very low suspect rate among children aged < 5 years; low performance of suspect management (68.5% suspects received further examinations); low utilization of other diagnostic methods; a high early defaulter rate (14.0%); and insufficient coverage of contact management (74.0%). This survey indicated that the Afghanistan national TB programme needs to develop plans to improve the quality of diagnosis, suspect management and contact management in paediatric TB cases.
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Hospitales de Enfermedades Crónicas , Hospitales de Distrito , Tuberculosis/tratamiento farmacológico , Adolescente , Afganistán/epidemiología , Niño , Preescolar , Humanos , Lactante , Sistema de Registros , Estudios Retrospectivos , Tuberculosis/diagnóstico , Tuberculosis/epidemiologíaRESUMEN
OBJECTIVES: Recently, the standard of care for advanced urothelial cancer (UC) has been changed by developing immune-checkpoint inhibitors (ICIs). However, its response rate is limited to 20-30%. The identification of biomarkers to predict the therapeutic effects of ICIs is urgently needed. The present study explored the association between immunohistochemical biomarkers and clinical outcomes in UC patients treated with pembrolizumab. PATIENTS AND METHODS: A total of 85 patients with UC who received pembrolizumab after chemotherapy from January 2018 to May 2020 were retrospectively reviewed. Tumor tissues were obtained for immunohistochemical study from 47 out of 85 patients. The protein expressions of PD-L1, WT1, Nectin-4, CD4, CD8, Foxp3, and CD68 in tumor cells and/or tumor infiltrating lymphocytes were immunohistochemically examined. The associations between protein expressions and overall survival (OS), progression-free survival (PFS), and disease control rate (DCR) were statistically analyzed. RESULTS: Patients with positive PD-L1 in tumor cells showed significantly worse OS (Log-rank test: HR 5.146, p = 0.001, Cox regression analysis: HR 4.331, p = 0.014) and PFS (Log-rank test: HR 3.31. p = 0.022), along with significantly lower DCR (14.3%) compared to the PD-L1 negative patients (67.5%). In addition, patients with strong expression of Nectin-4 in tumor cells showed significantly higher DCR (100%) than the other patients (50%). CONCLUSION: PD-L1 expression in tumor cells was associated with poor prognosis (OS and PFS) and low DCR. Interestingly, the strong expression of Nectin-4 was correlated with high DCR. PD-L1 and Nectin-4 expression in tumor cells could be prognostic biomarkers useful for pembrolizumab in patients with advanced UC.
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Anticuerpos Monoclonales Humanizados/uso terapéutico , Antineoplásicos Inmunológicos/uso terapéutico , Antígeno B7-H1/biosíntesis , Carcinoma de Células Transicionales/tratamiento farmacológico , Carcinoma de Células Transicionales/metabolismo , Moléculas de Adhesión Celular/biosíntesis , Neoplasias Urológicas/tratamiento farmacológico , Neoplasias Urológicas/metabolismo , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
ObjectivesRecently, the standard of care for advanced urothelial cancer (UC) has been changed by developing immune-checkpoint inhibitors (ICIs). However, its response rate is limited to 2030%. The identification of biomarkers to predict the therapeutic effects of ICIs is urgently needed. The present study explored the association between immunohistochemical biomarkers and clinical outcomes in UC patients treated with pembrolizumab.Patients and methodsA total of 85 patients with UC who received pembrolizumab after chemotherapy from January 2018 to May 2020 were retrospectively reviewed. Tumor tissues were obtained for immunohistochemical study from 47 out of 85 patients. The protein expressions of PD-L1, WT1, Nectin-4, CD4, CD8, Foxp3, and CD68 in tumor cells and/or tumor infiltrating lymphocytes were immunohistochemically examined. The associations between protein expressions and overall survival (OS), progression-free survival (PFS), and disease control rate (DCR) were statistically analyzed.ResultsPatients with positive PD-L1 in tumor cells showed significantly worse OS (Log-rank test: HR 5.146, p = 0.001, Cox regression analysis: HR 4.331, p = 0.014) and PFS (Log-rank test: HR 3.31. p = 0.022), along with significantly lower DCR (14.3%) compared to the PD-L1 negative patients (67.5%). In addition, patients with strong expression of Nectin-4 in tumor cells showed significantly higher DCR (100%) than the other patients (50%).ConclusionPD-L1 expression in tumor cells was associated with poor prognosis (OS and PFS) and low DCR. Interestingly, the strong expression of Nectin-4 was correlated with high DCR. PD-L1 and Nectin-4 expression in tumor cells could be prognostic biomarkers useful for pembrolizumab in patients with advanced UC.
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Humanos , Persona de Mediana Edad , Anticuerpos Monoclonales Humanizados/uso terapéutico , Antineoplásicos/uso terapéutico , Antígeno B7-H1/biosíntesis , Moléculas de Adhesión Celular/biosíntesis , Neoplasias Urológicas/tratamiento farmacológico , Neoplasias Urológicas/metabolismo , Carcinoma , Estudios RetrospectivosRESUMEN
Reduced expression in immortalized cells (REIC/Dkk-3), a member of the human Dickkopf (Dkk) family, is a growth suppressor in human and canine mammary tumours. Mammary gland tumours are common neoplasms with high malignancy in female cats. The purpose of this study was to clone the feline REIC/Dkk-3 homolog, investigate its expression in cell lines established from feline mammary gland tumours, and test its tumour suppressor function. Western blot analysis revealed that expression of the REIC/Dkk-3 protein was reduced in feline mammary carcinoma cell lines. Forced expression of REIC/Dkk-3 induced apoptosis in feline mammary tumour cell lines. These results demonstrate that REIC/Dkk-3 expression, which is downregulated in feline mammary tumour cell lines, results in the induction of apoptosis in these cells. Our findings suggest that feline REIC/Dkk-3 represents a potential molecular target for the development of therapies against feline mammary cancers.
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Péptidos y Proteínas de Señalización Intercelular/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Animales , Apoptosis , Enfermedades de los Gatos/metabolismo , Gatos , Línea Celular Tumoral/metabolismo , Clonación Molecular , Femenino , Neoplasias Mamarias Animales/metabolismoRESUMEN
To access the saliva level of 3-methoxy-4-hydroxy-phenylglycol (sMHPG) as an index of mental health in normal volunteers, we investigated the relationship between the sMHPG and the scores on the general health questionnaire-28 (GHQ-28). A total of 270 normal volunteers answered the GHQ-28 and the sMHPG levels were determined. The sMHPG levels in women and men were comparable. There was a significant negative correlation between the social dysfunction score on the GHQ-28 and sMHPG levels in women (P=0.0035), but not in men. Moreover, the sMHPG levels also correlated with the total GHQ-28 score (P=0.0205), the anxiety and the insomnia score (P=0.0306) in women. These data indicate a high social dysfunction score on the GHQ-28 to be associated with a reduced noradrenergic neuronal tone thus possibly reflecting psychomotor retardation in women.
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Metoxihidroxifenilglicol/metabolismo , Inventario de Personalidad/estadística & datos numéricos , Saliva/metabolismo , Adulto , Anciano , Ansiedad/fisiopatología , Ansiedad/psicología , Nivel de Alerta/fisiología , Trastorno Depresivo/fisiopatología , Trastorno Depresivo/psicología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Norepinefrina/fisiología , Psicometría/estadística & datos numéricos , Desempeño Psicomotor/fisiología , Valores de Referencia , Factores Sexuales , Trastornos del Inicio y del Mantenimiento del Sueño/fisiopatología , Trastornos del Inicio y del Mantenimiento del Sueño/psicología , Ajuste Social , Trastornos Somatomorfos/fisiopatología , Trastornos Somatomorfos/psicología , Estadística como AsuntoRESUMEN
Immunohistologic studies of 8 patients with squamous cell carcinoma (SCC) were undertaken using a series of monoclonal antibodies. In all of the patients, over 70% of the dermal infiltrates reacted with OKT3 and OKIal (HLA-DR), with a slight predominance of the OKT8+ suppressor/cytotoxic T subset (the mean OKT4/OKT8 ratio was 0.85). Both OKT4+ and OKT8+ subsets could be seen in contact with individual cancer cells. The percentage of OKB7+ (B) cells was less than 29% of the dermal infiltrates. Some Leu-7+ cells (less than 9% of the infiltrates) were seen in close association with individual cancer cells and none of these cells was present apart from the cancer cells. Few OKT6+ cells were observed in the papillary dermis and these had no relation to cancer cells. In the epidermis, OKT6+ dendritic cells remained within normal proportions. Staining with OKM1 revealed sporadic reactive cells. These results strongly suggest that besides T and B lymphocytes, Leu-7+ (natural killer) cells participate in a significant defense mechanism against SCC proliferation.
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Antígenos de Neoplasias/análisis , Antígenos de Superficie/análisis , Carcinoma de Células Escamosas/inmunología , Células Asesinas Naturales/inmunología , Neoplasias Cutáneas/inmunología , Anticuerpos Monoclonales , Antígenos de Diferenciación de Linfocitos T , Carcinoma de Células Escamosas/patología , Diferenciación Celular , Antígenos HLA-DR/análisis , Humanos , Inmunidad Celular , Neoplasias Cutáneas/patología , Linfocitos T/inmunologíaRESUMEN
The regulation of collagen gene expression in normal diploid human fetal fibroblasts (KMS-6 cells), and fibroblasts immortally transformed by treatment of KMS-6 with Co-60 gamma rays (KMST-6 cells) was compared to that of ones tumorigenically transformed by treatment of KMST-6 cells with Harvey murine sarcoma virus (KMST-6-Ras cells). Synthesized collagenous protein decreased to approximately 30% of that of normal fetal fibroblasts in both transformed cell lines, and the relative rate of collagen synthesis to total protein synthesis decreased about sixfold in KMST-6 cells and twelvefold in KMST-6-Ras cells. The m-RNA levels of type I collagen in both of these cell lines decreased to approximately 20% of that of the control fibroblasts, whereas type III collagen m-RNA levels decreased to only 9% of that of the control. The copy number of the collagen gene in both transformed cell lines was unaltered. The transcriptional rates of collagen alpha 1(I) and collagen alpha 1(III) in both cell lines decreased to 20% and 7% respectively of that of control. These data indicate that collagen synthesis was reduced at the transcriptional level in these transformed human fibroblasts.
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Colágeno/genética , Fibroblastos/fisiología , Línea Celular Transformada , Regulación de la Expresión Génica , Humanos , ARN/genética , ARN Mensajero/genética , Transcripción Genética/genéticaRESUMEN
Polyclonal activation of lymphocytes due to an unknown cause is considered to be one of the most important findings of systemic autoimmune disorders including systemic lupus erythematosus (SLE). In order to confirm the expression of the C-Myc protooncogene in lesional skin, tissue specimens from SLE were examined by the histo in situ hybridization method and a histochemical method using a specific antibody reactive with C-Myc related products. Twenty-two cases of SLE, six cases of DLE, one case of lupus erythematosus profundus, two cases of lichen planus, and five skin specimens from healthy volunteers were selected for the examination. In the SLE group, further comparative examination of diseased skin and normal skin from the same patient, and of diseased skin in an active stage and a stable stage in the same SLE patient with renal involvement, were carried out. In most of the active SLE cases, protooncogene expression had apparently increased as compared with the expression in the groups of inactive and treated SLE, active DLE, active lichen planus, and those with healthy skin. Even in normal-appearing skin from active SLE without other organic failure, the protooncogenes were not expressed very strongly.
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Genes myc , Lupus Eritematoso Sistémico/genética , Piel/metabolismo , Adolescente , Adulto , Femenino , Humanos , Lupus Eritematoso Sistémico/metabolismo , Masculino , Persona de Mediana Edad , Hibridación de Ácido Nucleico , Proteínas Proto-Oncogénicas c-myc/análisis , ARN Mensajero/análisisRESUMEN
Although Werner's syndrome (WS) is a premature aging disease and its fibroblasts typically grow poorly in culture, WS may cause abnormalities in connective tissue metabolism that are seldom seen in normal aging, such as scleroderma-like skin. In a preliminary report, we described increased collagen synthesis in fibroblasts derived from two WS patients. The present study was undertaken to determine the degree of the regulation of collagen gene expression in dermal fibroblasts from two other patients. Overproduction of collagenase sensitive protein was observed in WS fibroblasts. Collagen m-RNA levels, that were determined by hybridization of RNA blots with specific cDNA were about 2 times greater than those in the control cells. These results suggest that control of collagen synthesis in WS fibroblasts is altered at the transcriptional level.
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Colágeno/biosíntesis , Fibroblastos/análisis , ARN Mensajero/análisis , Síndrome de Werner/metabolismo , Síndrome de Werner/patología , Células Cultivadas , Colágeno/genética , Femenino , Humanos , Masculino , Persona de Mediana Edad , Transcripción GenéticaRESUMEN
One cause of the excessive deposition of collagen in systemic sclerosis is thought to be abnormal functioning of fibroblasts. The purpose of this study is to determine whether there is decreased expression of collagenase in systemic sclerosis fibroblasts. In this study, we analyzed collagen and collagenase expression in dermal fibroblasts derived from eight patients with systemic sclerosis and compared the findings with those from nine sex- and age-matched healthy subjects. Increased collagen synthesis accompanying enhanced mRNA levels was observed in two of eight strains, whereas all eight strains showed remarkable decreases in collagenase activity and production. There were no differences in the levels of collagenase mRNA between the systemic sclerosis strains and the normal strains. Results suggest that decreased collagenase expression is a characteristic of systemic sclerosis fibroblasts, and both increased collagen expression and decreased collagenase expression in systemic sclerosis fibroblasts may result in the excessive accumulation of collagen in patients with systemic sclerosis. It is also suggested that decreased collagenase expression is altered at translational and/or post-translational levels.
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Colagenasas/metabolismo , Esclerodermia Sistémica/enzimología , Esclerodermia Sistémica/patología , Piel/enzimología , Piel/patología , Adulto , Células Cultivadas , Femenino , Fibroblastos/enzimología , Humanos , Immunoblotting , Persona de Mediana EdadRESUMEN
The application of hapten to the skin of mice can induce contact sensitivity (CS). It has also been well established that draining lymph node (DLN) cells can induce CS to the hapten used for skin painting when injected into naive mice. This is true for DLN cells recovered about 24 h after skin painting with hapten. It is unclear, however, whether DLN cells recovered shortly after hapten application have the same ability. By using an adoptive transfer assay system, we examined the ability of DLN cells recovered from mice at various times after skin painting with hapten to induce CS. DLN cells harvested 18-24 h after the application of fluorescein isothiocyanate (FITC) or 2,4-dinitrofluorobenzene (DNFB) induced strong CS when injected into naive mice. DLN cells harvested 3-6 h after the application of FITC or DNFB induced either only weak or no CS but induced suppression of the subsequent immunization to the two haptens. The suppression was hapten-specific, MHC restricted, and associated with the appearance of splenic suppressor T lymphocytes. Analyses with antibodies and ultraviolet (UV) B radiation demonstrated that suppression-inducing cells in DLNs were Ia+, Thy-1(-), and functionally UV-sensitive. These data suggest that epicutaneous sensitization with hapten first induces immunologically specific suppressor activity in the draining lymph nodes, whereas immunogenic activity becomes predominant later.
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Dermatitis por Contacto/inmunología , Ganglios Linfáticos/citología , Linfocitos T Reguladores/inmunología , Traslado Adoptivo , Animales , Supervivencia Celular , Epítopos , Femenino , Haptenos/inmunología , Haptenos/farmacología , Tolerancia Inmunológica/inmunología , Activación de Linfocitos , Recuento de Linfocitos , Mesenterio/citología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C3H , Piel/inmunología , Bazo/citología , Linfocitos T Reguladores/citología , Linfocitos T Reguladores/efectos de la radiación , Rayos UltravioletaRESUMEN
Our previous work demonstrated that collagenase mRNA levels are increased in fibroblasts derived from patients with cutis laxa (CL). To pursue the mechanism of the upregulation of collagenase expression, we investigated transcriptional levels of the collagenase gene in CL fibroblasts. Fibroblasts cultured from the skin of three congenital CL patients were studied. Northern blot hybridization revealed 2.8- to 7.3-fold increases in collagenase mRNA levels in CL fibroblasts compared with normal cells. Nuclear run-off experiments demonstrated that the transcription rate of the collagenase gene in nuclei isolated from the same cells was 5.1- to 10.2-fold higher in the CL fibroblasts than in the controls. Transient transfection of a normal collagenase promoter-CAT construct into the cells further showed significantly enhanced transcriptional activity in CL but not in normal fibroblasts. Experiments of transient transfection of deleted or small substituted collagenase promoter-CAT constructs indicated that collagenase transcription in CL fibroblasts was activated the TPA-responsive element site of the collagenase promoter gene. Although the levels of Jun and Fos gene expression did not differ from those observed in normal fibroblasts, AP-1-binding activity, as measured by the ability to bind to an oligonucleotide containing a TPA-responsive element, was significantly elevated in CL fibroblasts as compared with normal fibroblasts. These data suggest that collagenase expression is upregulated at the transcriptional level by endogenous activation of DNA binding of AP-1 in CL fibroblasts [corrected].
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Colagenasas/genética , Cutis Laxo/enzimología , Regulación Enzimológica de la Expresión Génica , Regiones Promotoras Genéticas , Acetato de Tetradecanoilforbol/farmacología , Células Cultivadas , Preescolar , Femenino , Fibroblastos/enzimología , Humanos , Metaloproteinasa 3 de la Matriz , Metaloendopeptidasas/genética , Factor de Transcripción AP-1/metabolismo , Transcripción GenéticaRESUMEN
The fate of allogeneic (strains 13, 2, and JY-1) and autologous epidermal cell (EC) suspensions injected intradermally was investigated histologically in JY-1 strain guinea pigs. Epidermal cells were found to proliferate actively in the dermis and form EC nests with central keratinization. The significant reject reaction associated with necrosis of the epidermal structures was seen in due time in the animals implanted with allogeneic ECs. We attempted to assess the effect of cyclosporin A (CYA) on skin allograft survival by observing the fate of strain 13 ECs implanted intradermally into the CYA-treated JY-1. Successful prolongation of allograft survival with CYA was clearly demonstrated by this method. This is considered to be a useful experimental way for evaluation of skin allograft survival and to be suitable for routine use.
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Supervivencia de Injerto , Trasplante de Piel , Animales , Ciclosporinas/farmacología , Células Epidérmicas , Epidermis/trasplante , Estudios de Evaluación como Asunto , Supervivencia de Injerto/efectos de los fármacos , Cobayas , Inyecciones Intradérmicas , Masculino , Piel/citología , Trasplante HomólogoRESUMEN
Collagen metabolism was studied in cutis laxa by analyzing collagen and collagenase gene expression in three dermal fibroblast strains from patients with congenital cutis laxa and comparing them with fibroblasts obtained from age-matched healthy subjects. Normal collagen synthetic activity was observed in the cutis laxa fibroblasts. An increased level of collagenase mRNA and unaltered levels of alpha 1(I) and alpha 1(III) collagen mRNA were found in all cutis laxa cell strains by dot blot hybridization. Reduced levels of elastin mRNA were also detected in these strains. However, no qualitative differences in these mRNA transcripts were detected between the control and cutis laxa fibroblasts by Northern blot analysis. Collagenase activity in fibroblast culture supernatants was then measured using fluorescein isothiocyanate (FITC)-labeled type I collagen. Increased collagenolytic activity in cutis laxa fibroblast culture supernatants was also found. These data suggest that increased collagenase expression of fibroblasts is related to the structural abnormality of dermal connective tissue in cutis laxa.
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Colágeno/metabolismo , Cutis Laxo/metabolismo , Cutis Laxo/patología , Fibroblastos/metabolismo , Colagenasa Microbiana/genética , Colágeno/genética , Cutis Laxo/genética , Fibroblastos/enzimología , Expresión Génica , Humanos , ARN Mensajero/análisisRESUMEN
Gene expression of collagens VI, I, and III in Werner's syndrome was studied by measuring messenger RNA (mRNA) and protein production levels in four fibroblast strains from patients with Werner's syndrome and comparing them with age-matched healthy subjects. Levels of type VI collagen mRNA were decreased in all Werner's syndrome fibroblast strains and the decreases were in parallel in all three chains (alpha 1, alpha 2, and alpha 3) of type VI collagen. A coordinate increase of the alpha 1(I) and alpha 1(III) collagen mRNA levels was observed in three of the four Werner's syndrome fibroblast strains. However, no qualitative abnormality of these mRNA transcripts in Werner's syndrome fibroblasts were found by Northern blot analysis. Changes in type VI and type I collagen mRNA correlated well with production levels of corresponding proteins, as determined by immunologic assays. These data suggest that there are changes in expression of multiple connective tissue constituents in Werner's syndrome fibroblasts.
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Colágeno/genética , Expresión Génica , Síndrome de Werner/genética , Adulto , Colágeno/química , Femenino , Fibroblastos/química , Fibroblastos/metabolismo , Humanos , Masculino , Persona de Mediana Edad , ARN Mensajero/análisis , Síndrome de Werner/patologíaRESUMEN
SSA/Ro antigen is a soluble cellular component to which antibodies are frequently produced in patients with Sjögren's syndrome and systemic lupus erythematosus. Its exact location within the cell has yet to be determined. In this study we report the expression of SSA/Ro antigen in simian virus 40 (SV40)-transformed keratinocytes. The locations of SSA/Ro, U1RNP, and DNA antigens were studied by indirect immunofluorescence using monospecific antibodies. SSA/Ro antigen was detected in both the nucleus and cytoplasm of SV40-transformed keratinocytes tested with three monospecific sera. Primary cultured keratinocytes derived from adult human skin showed localized immunofluorescent staining within the nucleus. When Ca++ concentration of the medium was switched to 0.05 mM, these cells expressed cytoplasmic SSA/Ro antigens within 48 h. Depletion of the antibody activity with insolubilized human spleen extract abolished the staining. Surface expression of this antigen could not be detected in either primary or transformed cells. Localization of U1RNP and DNA was not altered. These results indicate that expression of SSA/Ro antigen in human keratinocytes is modulated by SV40 infection and that this antigen is expressed to a greater degree in cells that are less differentiated, transformed, or proliferating.
Asunto(s)
Autoantígenos/análisis , Transformación Celular Viral , Epidermis/inmunología , ARN Citoplasmático Pequeño , Ribonucleoproteínas , Humanos , Queratinas , Virus 40 de los SimiosRESUMEN
Involvement of protein kinases in the stimulation of cGMP-inhibited cAMP phosphodiesterase (PDE) activity by orthovanadate (vanadate) was studied. When the fat pads were incubated with 2 mM vanadate or 10 nM insulin, the stimulation of myelin basic protein kinase (MBPK) activity in the particulate by vanadate reached a maximum at 60 min. In contrast, insulin showed a transient increase at 20 min. A 60-min incubation of the fat pads with vanadate stimulated all activities of protein tyrosine kinase (PTK), MBPK, and PDE in the particulate, in a similar dose-dependent manner. Amiloride, a PTK inhibitor, inhibited the stimulations of three enzymes by vanadate in a similar concentration range. Enzyme fractions, which were separated from the solubilized particulate, were subjected to the immunoblot analysis. A fraction of MBPK was identified to contain a major protein of mol wt (44K) and a minor one (42K), both of which are immunoreactive with a mitogen-activated protein kinase (MAPK) antibody. The partially purified PDE activity was stimulated by the addition of the partially purified MBPK. The further stimulation was observed with the PTK-activated MBPK. These results suggest that vanadate stimulates in part the PDE activity through the activation of the particulate MBPK, probably MAPKs, by PTK sensitive to vanadate.
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3',5'-AMP Cíclico Fosfodiesterasas/metabolismo , Tejido Adiposo/enzimología , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , GMP Cíclico/farmacología , Proteínas Tirosina Quinasas/metabolismo , Vanadatos/farmacología , 3',5'-AMP Cíclico Fosfodiesterasas/aislamiento & purificación , Animales , Proteínas Quinasas Dependientes de Calcio-Calmodulina/aislamiento & purificación , Activación Enzimática , Fluoruros/farmacología , Glicerofosfatos/farmacología , Glucógeno Sintasa Quinasa 3 , Masculino , Modelos Biológicos , Compuestos de Potasio/farmacología , Proteínas Tirosina Quinasas/aislamiento & purificación , Ratas , Ratas WistarRESUMEN
When isolated rat fat pads were incubated with vanadate, the low Michaelis-Menten constant (Km) cAMP phosphodiesterase (PDE) activity in the microsomal fraction was increased in a time- and dose-dependent manner with vanadate. 3',5'-Cyclic GMP inhibited the vanadate-stimulated PDE activity with similar profile to the insulin-stimulated one. The stimulatory effect of vanadate was inhibited by inhibitors of tyrosine kinases such as amiloride, biochanin A, and genistein to various extents. Vanadate and insulin both showed the full effect in the absence of either K+, N+, or Ca2+ in the medium, while preincubation of the fat pads with a chelator of intracellular Ca2+ inhibited the vanadate action in a dose-dependent manner. The insulin action was not inhibited by it at tested concentrations. These results suggest that the vanadate action, in contrast to the insulin one, is dependent on the intracellular level of Ca2+. Preincubation of the fat pads with inhibitors of protein kinase C such as 1-(5-isoquinoline sulfonyl)-2-methylpiperazine (H-7) and staurosporine inhibited, in part, the vanadate action but did not inhibit the insulin one. Furthermore, vanadate increased the protein kinase C activity in fat pads but insulin did not increase. H-7 and amiloride showed a significant inhibition of stimulation of protein kinase C activity by vanadate. These results suggest that vanadate stimulates, in part, the 3',5'-cyclic GMP-inhibited low Km cAMP PDE activity in the microsomal fraction of fat pads through the activation of tyrosine kinase and protein kinase C-mediated processes.
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3',5'-AMP Cíclico Fosfodiesterasas/metabolismo , Tejido Adiposo/enzimología , GMP Cíclico/farmacología , Vanadatos/farmacología , 1-(5-Isoquinolinesulfonil)-2-Metilpiperazina , Alcaloides/farmacología , Amilorida/farmacología , Animales , Relación Dosis-Respuesta a Droga , Activación Enzimática/efectos de los fármacos , Insulina/farmacología , Isoquinolinas/farmacología , Cinética , Masculino , Microsomas/enzimología , Piperazinas/farmacología , Proteína Quinasa C/antagonistas & inhibidores , Proteína Quinasa C/metabolismo , Proteínas Tirosina Quinasas/metabolismo , Ratas , Ratas Endogámicas , Receptor de Insulina/efectos de los fármacos , Receptor de Insulina/fisiología , Estaurosporina , Vanadatos/administración & dosificaciónRESUMEN
Although it is considered that the lipoprotein metabolism in tumor plays an important role in growth and multiplication, it is not clear as to the details. Lipoprotein lipase (LPL) is a key enzyme responsible for the hydrolysis of lipoprotein-triacylglyceride. In this study, we examined the regulatory step of LPL in lipoprotein metabolism of Ehrlich ascites tumor and especially the enzyme-release from the tumor cells. When LPL was stimulated to release from the tumor cells by the low molecular weight dextran sulfate (3.2 kDa), cyclic AMP content in the tumor cells was observed to increase rapidly in a time-dependent manner up to 30 s; its maximal effect was 1.5-fold higher than the basal level of cyclic AMP. The increase in cyclic AMP content was more enhanced in the presence of isobutylmethylxanthine and was never suppressed by propranolol. Moreover, cyclic AMP-dependent protein kinase (PKA) activity in the tumor cells was also recognized to elevate in a time- and dose-dependent manner. In addition, the release of LPL activity from the tumor cells was inhibited by 2',5'-dideoxyadenosine. These results suggest that LPL in the tumor cells is released through a pathway involving an activation of PKA associated with the rapid increase in cyclic AMP content.
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AMP Cíclico/biosíntesis , Lipoproteína Lipasa/metabolismo , 1-Metil-3-Isobutilxantina/farmacología , Animales , Carcinoma de Ehrlich/metabolismo , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Sulfato de Dextran/farmacología , Masculino , Ratones , Propranolol/farmacologíaRESUMEN
Silica and related substances such as silicate have been proven to possess "adjuvant effects". We have previously reported a finding of polyclonal human T cell activation induced by silicate as a superantigen in vitro. In this study, we observed activation-induced cell death in human lymphocytes after stimulation with chrysotile, a kind of silicate. Apoptotic cells were detected flow cytometrically using the TUNEL assay, and the maximum appearance of TUNEL positive cells occurred on day 4 of incubation. Simultaneously the manifestation of small-sized cells in the specimens increased implying apoptosis. Fas expression on lymphocytes increased to day 3 of incubation with chrysotile, and then spontaneously decreased on day 4 when remarkable apoptosis could be detected. Based on these results it is conceivable that activation-induced cell death occurred through Fas-Fas ligand interaction in lymphocytes after stimulation with silicate in a concentration with which no acute cytotoxicity has been detected. Whether and how the repeated apoptosis in definite clones of lymphocytes causes the induction of sFas synthesis need clarification.