Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 29
Filtrar
2.
Lupus ; 22(5): 497-503, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23554038

RESUMEN

SH2D1A, also known as signaling lymphocytic activation molecule (SLAM)-associated protein (SAP), is an adaptor protein. Recently, it was reported that SAP deficient mice were protected from systemic lupus erythematosus (SLE). In this study, we postulated SH2D1A gene to be a candidate susceptibility gene for SLE and analyzed its association with SLE. A case-control association study was conducted on 5 tag single nucleotide polymorphisms (SNPs) in SH2D1A region in 506 Japanese female SLE patients and 330 healthy female controls. The luciferase assay was performed to determine the functional role of the SNP associated with SLE. One SNP in the intron 2, rs2049995, showed association with SLE (p=0.0110, odds ratio (OR) 1.97, 95% confidence interval (CI) 1.16-3.34, under the dominant model). The association of rs2049995 seemed to be stronger in the subset with the age of onset less than 20 years (p=0.0067, OR 2.65, 95% CI 1.28-5.46). Functional evaluation of rs2049995 showed that reporter gene activity was increased 1.9-fold for the susceptible allele compared with the resistant allele. An intronic SNP of SH2D1A is associated with SLE.


Asunto(s)
Péptidos y Proteínas de Señalización Intracelular/genética , Lupus Eritematoso Sistémico/genética , Adulto , Pueblo Asiatico , Estudios de Casos y Controles , Femenino , Predisposición Genética a la Enfermedad , Humanos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Intrones , Japón , Células Jurkat , Leucocitos Mononucleares/metabolismo , Leucocitos Mononucleares/patología , Luciferasas , Lupus Eritematoso Sistémico/metabolismo , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple , Proteína Asociada a la Molécula de Señalización de la Activación Linfocitaria
3.
J Clin Pharm Ther ; 37(1): 117-21, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21128990

RESUMEN

WHAT IS KNOWN AND OBJECTIVE: Tumour necrosis factor-α (TNF-α)-blocking agents are increasingly used in the management of refractory rheumatoid arthritis (RA). Although effective, they are associated with rare but potentially fatal adverse effects, including interstitial lung disease (ILD). In patients with pre-existing ILD, eternacept (ETN) monotherapy is often regarded as a suitable choice. Other anti-TNF-α blockers such as infliximab and adalimumab, are used in combination therapy with methotrexate (MTX) in most of the cases. We report on a case of fatal exacerbation of ILD in a patient given ETN monotherapy and review the literature on ETN-associated ILD. METHODS: We report on a case of a 75-year-old male with RA who developed severe ILD after the introduction of ETN, and we undertook a literature search to identify other reports of similar cases. We then critically assessed those reports. RESULTS AND DISCUSSION: In addition to our case, 11 other patients have been reported to have developed ILD in association with the use of ETN. Six patients had pre-existing ILD. Although four patients received MTX, eight patients developed severe ILD without MTX. Ten patients recovered after termination of ETN, although two patients died. WHAT IS NEW AND CONCLUSION: Although ETN is often regarded as safe for patients with ILD, our case and the literature reports suggest that caution is still required.


Asunto(s)
Antirreumáticos/uso terapéutico , Artritis Reumatoide/tratamiento farmacológico , Inmunoglobulina G/uso terapéutico , Enfermedades Pulmonares Intersticiales/complicaciones , Receptores del Factor de Necrosis Tumoral/uso terapéutico , Adulto , Anciano , Antirreumáticos/efectos adversos , Artritis Reumatoide/complicaciones , Etanercept , Resultado Fatal , Femenino , Humanos , Inmunoglobulina G/efectos adversos , Enfermedades Pulmonares Intersticiales/etiología , Enfermedades Pulmonares Intersticiales/fisiopatología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Índice de Severidad de la Enfermedad
5.
Biochim Biophys Acta ; 773(1): 83-90, 1984 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-6329280

RESUMEN

Sarcolemmal fractions of vascular smooth muscles were prepared from porcine thoracic aortae by differential and sucrose density gradient centrifugation. In these fractions, there was a high activity of 5'-nucleotidase, a putative marker enzyme of plasma membrane, and a low activity of rotenone insensitive NADH-cytochrome c reductase a marker of sarcoplasmic reticulum. In these fractions, the Ca2+ uptake was ATP-dependent. A low concentration of saponin which inhibited Ca2+ uptake by the plasma membrane but not by the sarcoplasmic reticulum, inhibited 65% of the Ca2+ uptake of this fraction. The Ca2+ uptake of this fraction was enhanced by cAMP- and cGMP-dependent protein kinases, and by calmodulin. The cAMP-dependent protein kinase enhanced the phosphorylation of 28 and 22 kDa proteins, while the cGMP-dependent protein kinase phosphorylated the 35 kDa protein. The phosphorylation of 100, 75, 65, 41 and 22 kDa proteins was enhanced by Ca2+ and calmodulin. These results indicate that cAMP- and cGMP-dependent protein kinases as well as calmodulin play important roles in Ca2+ transport in the sarcolemma, and that the phosphorylated proteins may be associated with an enhancement of Ca2+ transport in the sarcolemma.


Asunto(s)
Calcio/metabolismo , Calmodulina/farmacología , Músculo Liso Vascular/metabolismo , Proteínas Quinasas/metabolismo , Sarcolema/metabolismo , Animales , Aorta Torácica/metabolismo , Transporte Biológico Activo/efectos de los fármacos , AMP Cíclico/farmacología , GMP Cíclico/farmacología , Cinética , Fosforilación , Porcinos
6.
Biochim Biophys Acta ; 763(4): 339-45, 1983 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-6652113

RESUMEN

Effects of N-formyl chemotactic peptides on the Ca2+ influx and efflux were investigated in guinea-pig peritoneal macrophages using an isotope tracer. fMet-Leu-Phe did not enhance the influx of 45Ca2+ into macrophages, whereas it stimulated the efflux of 45Ca2+ from macrophages at concentrations ranging from 10(-10) M to 10(-7) M. fMet-Met-Met and fMet-Leu also stimulated the 45Ca2+ efflux, albeit at much higher concentrations, while there was no stimulation with fMet. The mitochondrial inhibitors, oligomycin and NaN3, did not modify the 45Ca2+ efflux induced by the chemoattractants, yet they did induce the release of 45Ca2+ from the mitochondria. On the other hand, higher concentrations of the calmodulin antagonists, chlorpromazine and trifluoperazine, induced the release of 45Ca2+ from the NaN3-insensitive Ca2+ store site and mimicked the enhancement of the 45Ca2+ efflux by N-formyl chemotactic peptides. Thus, N-formyl chemotactic peptides appear to increase the levels of intracellular free Ca2+ in guinea-pig peritoneal macrophages, probably by inducing the release of Ca2+ from the NaN3-insensitive Ca2+ store site.


Asunto(s)
Calcio/metabolismo , Macrófagos/metabolismo , N-Formilmetionina Leucil-Fenilalanina/farmacología , Animales , Transporte Biológico Activo/efectos de los fármacos , Factores Quimiotácticos/farmacología , Clorpromazina/farmacología , Cobayas , Cinética , Macrófagos/efectos de los fármacos , Relación Estructura-Actividad
7.
Am J Hypertens ; 3(12 Pt 2): 291S-298S, 1990 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-2078315

RESUMEN

It is generally acknowledged that calcium plays a major role in the generation of vascular tone. However, in recent years it has become increasingly evident that relatively calcium-insensitive pathways of excitation-contraction coupling also exist in the vascular smooth muscle cell. Possible mechanisms of vascular smooth muscle contraction and their possible role in the pathophysiology of hypertension are reviewed. The rationale for the use of calcium channel blockers in the treatment of hypertension is discussed.


Asunto(s)
Calcio/fisiología , Tono Muscular/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , Bloqueadores de los Canales de Calcio/uso terapéutico , Humanos , Hipertensión/tratamiento farmacológico , Hipertensión/fisiopatología
8.
J Biochem ; 94(4): 1155-63, 1983 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-6654849

RESUMEN

Passive permeability of the endoplasmic reticulum of saponin-treated macrophages to Ca2+ was studied by the filtration method using 45Ca. The Ca2+ release from the endoplasmic reticulum of macrophages was enhanced by the presence of submicromolar concentrations of Ca2+ in the medium. The Ca2+ release was enhanced by caffeine, and suppressed by MgCl2. These phenomena are similar to the Ca2+-induced Ca2+ release reported for the sarcoplasmic reticulum of skeletal muscle. On the other hand, adenine suppressed the Ca2+ release from the endoplasmic reticulum, while it reportedly enhanced the Ca2+-induced Ca2+ release of the skeletal muscle. The threshold concentration of Ca2+ for the Ca2+-induced Ca2+ release was approximately 10(-8) M in the presence of 0.95 mM MgCl2 in macrophages. The spontaneous spreading of macrophages and spontaneous migration of macrophages were inhibited by adenine, and also by caffeine in spite of the enhancement of the Ca2+-induced Ca2+ release.


Asunto(s)
Calcio/metabolismo , Retículo Endoplásmico/metabolismo , Macrófagos/metabolismo , Animales , Calcio/farmacología , Cobayas , Cinética , Macrófagos/efectos de los fármacos , Macrófagos/ultraestructura , Microscopía Electrónica , N-Formilmetionina Leucil-Fenilalanina/farmacología , Neutrófilos/metabolismo , Permeabilidad , Saponinas/farmacología , Retículo Sarcoplasmático/efectos de los fármacos
9.
J Biochem ; 97(6): 1575-82, 1985 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-3875610

RESUMEN

Inositol 1,4,5-trisphosphate (InsP3) releases Ca2+ from the non-mitochondrial Ca2+ store site of various types of cells. To study the mechanisms of the Ca2+ release from the store site, the effect of InsP3 on the passive Ca2+ release and influx, and the active Ca2+ uptake in the presence of oxalate, was examined using saponin-treated guinea pig peritoneal macrophages. InsP3 stimulated the passive Ca2+ release and influx. Although InsP3 slightly inhibited the active Ca2+ uptake in the presence of oxalate, it seems unlikely that the Ca2+ release by this agent is caused by the inhibition of the Ca2+ uptake, because the addition of apyrase or hexokinase (which removes ATP within 30 s, so that no more Ca2+ can be accumulated) or vanadate (which inhibits the Ca2+ uptake) resulted in very slow release of Ca2+. These results suggest that the Ca2+ permeability of the Ca2+ store membrane is increased by InsP3. InsP3 did not cause an increase in the Ca2+ permeability of phospholipid vesicles (liposomes), indicating that this agent may bring about Ca2+ release by a specific effect on the physiologically relevant Ca2+ channels or carriers in the non-mitochondrial Ca2+ store site. The passive Ca2+ release by InsP3 was enhanced by ATP and an unhydrolyzable ATP analogue, 5'-adenylyimidodiphosphate, but not by ADP or AMP. The passive Ca2+ release by InsP3 was observed even at 0 degree C.


Asunto(s)
Calcio/metabolismo , Fosfatos de Inositol/farmacología , Membranas Intracelulares/metabolismo , Macrófagos/metabolismo , Saponinas/farmacología , Fosfatos de Azúcar/farmacología , Adenosina Trifosfato/fisiología , Animales , Eritrocitos/metabolismo , Cobayas , Humanos , Técnicas In Vitro , Inositol 1,4,5-Trifosfato , Membranas Intracelulares/efectos de los fármacos , Liposomas/metabolismo , Cavidad Peritoneal , Permeabilidad , Vanadatos , Vanadio/farmacología
10.
Intern Med ; 38(7): 547-55, 1999 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10435360

RESUMEN

OBJECT: We describe the characteristics of three patients with CD56+CD7+ stem cell leukemia/lymphoma. METHODS: These blasts were analyzed for morphologic, karyotypic, immunophenotypic, and immunogenotypic features using Southern blot and polymerase chain reaction analysis. MATERIALS: Peripheral blood, bone marrow aspirates, or biopsied mediastinal tumor specimens of three CD56+CD7+ stem cell leukemia/lymphoma patients were investigated. RESULTS: The bone marrow of all patients showed myeloperoxidase (MPO) negative blast cells with basophilic cytoplasm and distinct nucleoli with no azurophilic granules. The blasts of two patients were classified as acute lymphoblastic leukemia (L2). The liver, spleen, and lymph nodes were unaffected in all patients. All had an aggressive clinical course. The blasts were strongly positive for both CD7 and CD56 but negative for other T-lineage associated antigens, including CD1, CD2, surface membrane CD3, cytoplasmic CD3c (2/2), CD4, CD5 and CD8. The additional antigens were recognized as follows: CD19 (1/3 cases) as a B lineage, CD33 (1/3) as a myeloid marker, CD34 (2/3) as a stem cell, CD38 (1/1) and HLA-DR (2/3). When the patients relapsed, the phenotypes changed to blasts positive for CD5, CD10 and CD13 in patient 1, CD5 in patient 2, and CD33 in patient 3. MPO, however, remained negative. Cytogenetic analysis showed no common abnormal karyotype. All had a common D2-Jdelta1 induced by T-cell specific enhancer. Rearrangement of TCR beta and gamma genes occurred in patient 2, and IgH and TCR beta underwent rearrangement in patient 3. CONCLUSION: Although a more comprehensive case analysis is necessary, these data suggest the possibility that the blasts of the present cases come from a common lymphoid precursor (T, NK, and B cell) or from a NKT precursor as the fourth lymphoid lineage.


Asunto(s)
Antígenos CD7/metabolismo , Antígeno CD56/metabolismo , Reordenamiento Génico de la Cadena delta de los Receptores de Antígenos de los Linfocitos T , Leucemia/genética , Leucemia/inmunología , Linfoma/genética , Linfoma/inmunología , Células Madre Neoplásicas/inmunología , Enfermedad Aguda , Adulto , Linfocitos B/inmunología , Linfocitos B/patología , Secuencia de Bases , Citogenética , Cartilla de ADN/genética , Reordenamiento Génico de Cadena Pesada de Linfocito B , Reordenamiento Génico de la Cadena beta de los Receptores de Antígenos de los Linfocitos T , Reordenamiento Génico de la Cadena gamma de los Receptores de Antígenos de los Linfocitos T , Genotipo , Humanos , Inmunofenotipificación , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/patología , Leucemia/patología , Linfoma/patología , Masculino , Persona de Mediana Edad , Células Madre Neoplásicas/patología , Linfocitos T/inmunología , Linfocitos T/patología
11.
Jpn J Antibiot ; 49(12): 1049-61, 1996 Dec.
Artículo en Japonés | MEDLINE | ID: mdl-9032592

RESUMEN

One hundred and nine patients with infections concurrent with hematopoietic disorders were treated with imipenem/cilastatin sodium (IPM/CS) either alone (IPM/CS monotherapy) or in combination with other antimicrobial drugs (IPM/CS combination therapy). The following results were obtained. 1. One hundred and nine patients were allocated at random to two groups: 53 patients to IPM/CS monotherapy and 56 patients to IPM/CS combination therapy. Fourteen patients (6 and 8 in the 2 groups, respectively) were excluded from the clinical evaluation. There were not significant differences between the two groups with respect to the background. 2. The efficacy rates of the 2 treatments against bacterial infections were as follows: in the IPM/CS monotherapy group, 62.5% in 8 patients with sepsis, 75.0% in 23 patients with fever of undetermined origin (FUO), 50.0% in 10 patients with pneumonia, and 68.3% in the 47 patients, and in the IPM/CS combination group, 85.7% in 7 patients with sepsis, 63.6% in 24 patients with FUO, 50.5% in 8 patients with pneumonia, and 67.4% in the 48 patients. The differences between the two groups were not significant. 3. Among the drugs used in combination with IPM/CS, antibiotics other than penicillins, cephalosporins, and aminoglycosides were used in 12 patients and a high efficacy rate of 91.7% was obtained. 4. Bacteriologically, 19 and 17 strains were isolated from the IPM/CS monotherapy and combination therapy groups respectively, and the eradication rates were 100% and 88.9% respectively. 5. Side effects were noted in 2 patients in the IPM/CS monotherapy group and 7 in the combination therapy group, but all of these resolved after discontinuation or completion of the treatment. The efficacies against severe bacterial infections in the presence of hematopoietic disorders were not different between IPM/CS alone and IPM/CS in combination with other antibiotics. Adverse reactions were uncommon with the monotherapy.


Asunto(s)
Infecciones Bacterianas/tratamiento farmacológico , Quimioterapia Combinada/administración & dosificación , Enfermedades Hematológicas/complicaciones , Infecciones Oportunistas/tratamiento farmacológico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Aminoglicósidos , Antibacterianos/administración & dosificación , Infecciones Bacterianas/complicaciones , Cefalosporinas/administración & dosificación , Cilastatina/administración & dosificación , Combinación Cilastatina e Imipenem , Combinación de Medicamentos , Femenino , Humanos , Imipenem/administración & dosificación , Huésped Inmunocomprometido , Masculino , Persona de Mediana Edad , Infecciones Oportunistas/complicaciones , Penicilinas/administración & dosificación
12.
Rinsho Ketsueki ; 30(8): 1294-8, 1989 Aug.
Artículo en Japonés | MEDLINE | ID: mdl-2601048

RESUMEN

We describe two cases of gastrointestinal lymphoma associated with rapid bone marrow dissemination after surgical resection. Case 1: A 73-year-old male was diagnosed as having malignant lymphoma originating from ileocaecal region (diffuse medium-sized, B cell type). Tumor (8 x 8 cm) was resected but infiltrated to the peritoneum and curative operation could not be done. Two weeks after operation, elevation of LDH, pancytopenia and bone marrow infiltration of lymphoma cells developed and he died of respiratory failure. Case 2: A 69-year-old female was diagnosed as having remnant gastric lymphoma (diffuse large, B cell type). Tumor size was 5 x 4 cm and swelling of the third lymph nodes was found, so curative operation could not be done. Two months after operation bone marrow infiltration of lymphoma cells was observed and she is now undergoing chemotherapy. Surgical resection is performed in the majority of patients with localized gastrointestinal lymphoma. But the operation of the advanced case must be carefully done, because the operative procedure may sometimes facilitate growth and metastasis of tumor.


Asunto(s)
Médula Ósea/patología , Neoplasias Gastrointestinales/patología , Linfoma/patología , Anciano , Linfocitos B , Femenino , Neoplasias Gastrointestinales/cirugía , Humanos , Linfoma/cirugía , Masculino , Metástasis de la Neoplasia , Periodo Posoperatorio
13.
Rinsho Ketsueki ; 30(5): 746-51, 1989 May.
Artículo en Japonés | MEDLINE | ID: mdl-2795886

RESUMEN

We describe a case of adult T-cell leukemia (ATL) with vertebral bone invasion, who developed acute paraplegia and responded well to irradiation and combined chemotherapy. A 36-year-old man born in Tsushima Island was admitted to our hospital in May 1987, because of a sudden onset of paraplegia, hypesthesia below the level of 7th thoracic vertebra and vesicorectal disturbance. The white blood cell count was 9,500/microliter with 16% of abnormal lymphocytes showing lobulated nuclei. The surface marker analysis revealed that CD3, CD4, CD8 and CD25 positive cells were 88.1, 83.9, 6.4 and 1.3% of the peripheral mononuclear cells, respectively. Anti-ATLA antibody was positive. Serum calcium level was elevated. Bone scintigraphy showed multiple vertebral bone lesions. Vertebral bone mass and a compressed spinal cord in the 7th thoracic level were confirmed by CT scanning and MR imaging. Cerebral spinal fluid was negative for tumor cells. A diagnosis of ATL was made. Irradiation and combination chemotherapy improved bone lesions and neurological signs and the disease was well controlled by maintenance chemotherapy up to the present (August, 1988).


Asunto(s)
Leucemia-Linfoma de Células T del Adulto/complicaciones , Enfermedades de la Médula Espinal/etiología , Neoplasias de la Columna Vertebral/complicaciones , Enfermedad Aguda , Adulto , Humanos , Leucemia-Linfoma de Células T del Adulto/patología , Masculino , Invasividad Neoplásica , Neoplasias de la Columna Vertebral/patología , Vértebras Torácicas
14.
Fukuoka Igaku Zasshi ; 81(11): 384-9, 1990 Nov.
Artículo en Japonés | MEDLINE | ID: mdl-2272600

RESUMEN

We report two cases of mosaic karyotype (45XO/46XiXq) Turner's syndrome with unique bone appearance. The cases were 44 and 34 year-old women and latter was complicated by Hashimoto's thyroiditis (hypothyroidism). Following the systemic bone surveys, we found the patients showed not only osteoporotic bone change and short stature, but also spondyloepiphyseal dysplasia (SED) like bone appearance (thinness of vertebral bodies, irregularity of vertebral end-plates, shortness of femoral necks, Coxa valga, Coxa magna and hypoplasia of acetabula). Those findings can not be explained by degenerative bone changes like osteoporosis, rather are suggestive the sequelae of malgrowth of the bone system in Turner's syndrome.


Asunto(s)
Osteocondrodisplasias/etiología , Síndrome de Turner/complicaciones , Adulto , Femenino , Humanos
17.
Biochem Biophys Res Commun ; 120(2): 481-5, 1984 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-6610416

RESUMEN

Effects of inositol 1,4,5- trisphosphate , extracted from human erythrocyte ghosts, on Ca2+ release from intracellular store sites were studied in saponin-treated single muscle cells of the porcine coronary artery. Application of micromolar concentrations of inositol 1,4,5- trisphosphate released Ca2+ from the intracellular non-mitochondrial store sites, within 1 min. However, when the concentrations of free Ca2+ were over 1.5 X 10(-6) M, the release of Ca2+ by this agent was inhibited. The Ca2+ releasing mechanism differed from that seen with A23187, therefore this release of Ca2+ from store sites was not due to Ca2+ ionophore actions. This agent may play the role of messenger in increasing the cytosolic Ca2+, provoking pharmaco-mechanical coupling, and thus producing the contraction.


Asunto(s)
Calcio/metabolismo , Vasos Coronarios/metabolismo , Fosfatos de Inositol/farmacología , Fosfatos de Azúcar/farmacología , Animales , Arterias/metabolismo , Calcio/farmacología , Vasos Coronarios/efectos de los fármacos , Membrana Eritrocítica/análisis , Humanos , Inositol 1,4,5-Trifosfato , Cinética , Contracción Muscular , Saponinas/farmacología , Porcinos
18.
J Physiol ; 440: 85-93, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-1839559

RESUMEN

1. The effects of the vasodilators atrial natriuretic peptide (ANP) and forskolin were determined on isometric force, intracellular ionized Ca2+ concentration ([Ca2+]i) as indicated by aequorin, and myosin light chain (MLC) phosphorylation in ferret aorta. 2. Atrial natriuretic peptide (10(-7) M) inhibited intrinsic tone with an associated significant decrease in [Ca2+]i. ANP also inhibited the contraction induced by KCl with a significant decrease in [Ca2+]i. MLC phosphorylation induced by KCl was inhibited by ANP. 3. Forskolin (10(-6) M) decreased the intrinsic tone without significantly decreasing [Ca2+]i, although MLC phosphorylation was significantly decreased. 4. A calcium-force curve was constructed by plotting the calibrated aequorin light signal against the resulting force. The control (potassium-generated) calcium-force curve was not shifted by ANP, but was significantly shifted to the right by forskolin. Forskolin also shifted the phosphorylation-calcium curve to the right without changing the phosphorylation-force curve. 5. We conclude that the vasodilatory effect of ANP on vascular smooth muscle is mainly due to a decrease in [Ca2+]i. On the other hand, the effect of forskolin is via both a decrease in [Ca2+]i and a change in the Ca2+ requirement for MLC phosphorylation.


Asunto(s)
Calcio/fisiología , Relajación Muscular/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , Miosinas/metabolismo , Animales , Aorta Torácica/efectos de los fármacos , Factor Natriurético Atrial/farmacología , Colforsina/farmacología , Técnicas de Cultivo , Hurones , Masculino , Relajación Muscular/fisiología , Fosforilación/efectos de los fármacos
19.
Am J Physiol ; 261(2 Pt 1): C253-8, 1991 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-1872370

RESUMEN

The mechanism of contraction of vascular smooth muscle by prostaglandin F2 alpha (PGF2 alpha) was examined by simultaneous measurement of the intracellular Ca2+ concentration [( Ca2+]i), force, and myosin light-chain (MLC) phosphorylation in ferret aorta. In the presence of 2.5 mM extracellular Ca2+, PGF2 alpha (10(-5)M) produced a tonic contraction with a transient spike in [Ca2+]i, followed by a relatively small sustained increase in [Ca2+]i (from a basal level of 2.32 +/- 0.07 x 10(-7) to 2.72 +/- 0.05 x 10(-7) M). In Ca(2+)-free bathing media, PGF2 alpha also produced a tonic contraction with a small spike in [Ca2+]i, indicating a release of Ca2+ from intracellular store sites, followed by no significant increase in [Ca2+]i. Ca(2+)-force curves were constructed by plotting the calibrated steady-state aequorin light signal against the resulting steady-state force. The curve was significantly shifted to the left by PGF2 alpha. PGF2 alpha also shifted the Ca(2+)-phosphorylation curve to the left. These results suggest that PGF2 alpha causes contraction by both elevating [Ca2+]i and decreasing the Ca2+ requirement for MLC phosphorylation. The data are consistent with a mechanism where there is either an increase in activity of MLC kinase or a decrease in phosphatase activity. Additionally, there was a smaller, but statistically significant, effect to increase force at any one phosphorylation level, pointing to the possibility of regulation of contractile force separate from MLC phosphorylation.


Asunto(s)
Calcio/fisiología , Dinoprost/metabolismo , Miosinas/metabolismo , Animales , Aorta/metabolismo , Hurones , Masculino , Contracción Muscular/fisiología , Concentración Osmolar , Fosforilación , Potasio/farmacología , Análisis de Regresión
20.
Proc Soc Exp Biol Med ; 197(2): 201-7, 1991 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-2031056

RESUMEN

We examined the effect of silver ion on Ca2+ mobilization from intracellular stores in permeabilized HL-60 cells using a filtration method and 45Ca2+. In HL-60 cells preloaded with Ca2+ in the presence of ATP, micromolar concentrations of AgNO3 elicited marked Ca2+ release within 1 min. The AgNO3-induced Ca2+ release was not affected by the free Ca2+ concentration in the medium. Equivalent concentrations of AgNO3 inhibited energy-dependent Ca2+ uptake as well as oxalate-supported Ca2+ uptake. In passive Ca2+ release experiments when ATP was completely depleted in the solution, AgNO3 also triggered Ca2+ release. Sulfhydryl protecting agents such as 2-mercaptoethanol, dithiothreitol, and glutathione (reduced form) blocked the AgNO3-induced Ca2+ release. From these results, we conclude that the apparent Ca2+ release induced by AgNO3 is mainly due to inhibition of the Ca2+ pump with increased permeability for Ca2+ and partly due to a direct effect on the Ca2+ release channel, probably by modification of sulfhydryl groups on these proteins.


Asunto(s)
Calcio/metabolismo , Saponinas/farmacología , Nitrato de Plata/farmacología , Línea Celular , Permeabilidad de la Membrana Celular , Granulocitos/efectos de los fármacos , Granulocitos/metabolismo , Humanos , Compuestos de Sulfhidrilo/farmacología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA