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1.
Diabetologia ; 52(7): 1369-80, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19418039

RESUMO

AIMS/HYPOTHESIS: We measured serum C-peptide (at least 0.167 nmol/l) in 54 of 141 (38%) patients with chronic type 1 diabetes and sought factors that might differentiate those with detectable C-peptide from those without it. Finding no differences, and in view of the persistent anti-beta cell autoimmunity in such patients, we speculated that the immunosuppression (to weaken autoimmune attack) and euglycaemia accompanying transplant-based treatments of type 1 diabetes might promote recovery of native pancreatic beta cell function. METHODS: We performed arginine stimulation tests in three islet transplant and four whole-pancreas transplant recipients, and measured stimulated C-peptide in select venous sampling sites. On the basis of each sampling site's C-peptide concentration and kinetics, we differentiated insulin secreted from the individual's native pancreatic beta cells and that secreted from allografted beta cells. RESULTS: Selective venous sampling demonstrated that despite long-standing type 1 diabetes, all seven beta cell allograft recipients displayed evidence that their native pancreas secreted C-peptide. Yet even if chronic immunosuppression coupled with near normal glycaemia did improve native pancreatic C-peptide production, the magnitude of the effect was quite small. CONCLUSIONS/INTERPRETATION: Some native pancreatic beta cell function persists even years after disease onset in most type 1 diabetic patients. However, if prolonged euglycaemia plus anti-rejection immunosuppressive therapy improves native pancreatic insulin production, the effect in our participants was small. We may have underestimated pancreatic regenerative capacity by studying only a limited number of participants or by creating conditions (e.g. high circulating insulin concentrations or immunosuppressive agents toxic to beta cells) that impair beta cell function.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 1 , Imunossupressores/uso terapêutico , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/transplante , Transplante das Ilhotas Pancreáticas , Adulto , Biomarcadores/sangue , Peptídeo C/sangue , Peptídeo C/metabolismo , Doença Crônica , Diabetes Mellitus Tipo 1/imunologia , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/cirurgia , Feminino , Veias Hepáticas , Humanos , Insulina/sangue , Insulina/metabolismo , Secreção de Insulina , Transplante de Rim , Masculino , Pessoa de Meia-Idade , Transplante de Pâncreas , Veia Porta , Regeneração/fisiologia , Transplante Homólogo
2.
Biomacromolecules ; 2(1): 32-6, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11749152

RESUMO

A lower critical solution temperature (LCST) in an aqueous environment has been observed with poly(N-isopropylacrylamide) (pNIPAM) deposited onto solid surfaces from a plasma glow discharge of NIPAM vapor. The synthesis and spectroscopic data (ESCA, FTIR) for the plasma polymerized NIPAM (ppNIPAM) shows a remarkable retention of the monomer structure. The phase transition at 29 degrees C was measured by a novel AFM method. The phase transition was surprising because of the expectation that the plasma environment would destroy the specific NIPAM structure associated with the thermal responsiveness. The phase change of ppNIPAM is also responsible for the changes in the level of the meniscus when coated capillaries are placed in warm and cold water. Plasma polymerization of NIPAM represents a one-step method to fabricate thermally responsive coatings on real-world biomaterials without the need for specially prepared substrates and functionalized polymers.


Assuntos
Acrilamidas/química , Polímeros/síntese química , Microscopia de Força Atômica , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termodinâmica
3.
Blood ; 98(6): 1687-94, 2001 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-11535498

RESUMO

Delayed donor red cell engraftment and pure red cell aplasia (PRCA) are well-recognized complications of major ABO-incompatible hematopoietic stem cell transplantation (SCT) performed by means of myeloablative conditioning. To evaluate these events following reduced-intensity nonmyeloablative SCT (NST), consecutive series of patients with major ABO incompatibility undergoing either NST (fludarabine/cyclophosphamide conditioning) or myeloablative SCT (cyclophosphamide/high-dose total body irradiation) were compared. Donor red blood cell (RBC) chimerism (initial detection of donor RBCs in peripheral blood) was markedly delayed following NST versus myeloablative SCT (median, 114 versus 40 days; P <.0001) and strongly correlated with decreasing host antidonor isohemagglutinin levels. Antidonor isohemagglutinins declined to clinically insignificant levels more slowly following NST than myeloablative SCT (median, 83 versus 44 days; P =.03). Donor RBC chimerism was delayed more than 100 days in 9 of 14 (64%) and PRCA occurred in 4 of 14 (29%) patients following NST, while neither event occurred in 12 patients following myeloablative SCT. Conversion to full donor myeloid chimerism following NST occurred significantly sooner in cases with, compared with cases without, PRCA (30 versus 98 days; P =.008). Cyclosporine withdrawal appeared to induce graft-mediated immune effects against recipient isohemagglutinin-producing cells, resulting in decreased antidonor isohemagglutinin levels and resolution of PRCA following NST. These data indicate that significantly delayed donor erythropoiesis is (1) common following major ABO-incompatible NST and (2) associated with prolonged persistence of host antidonor isohemagglutinins. The clinical manifestations of these events are affected by the degree and duration of residual host hematopoiesis.


Assuntos
Sistema ABO de Grupos Sanguíneos , Doadores de Sangue , Eritropoese , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Aplasia Pura de Série Vermelha/etiologia , Condicionamento Pré-Transplante , Sistema ABO de Grupos Sanguíneos/imunologia , Eritrócitos/fisiologia , Doença Enxerto-Hospedeiro/etiologia , Hemaglutininas/metabolismo , Humanos , Imunoglobulinas/biossíntese , Cinética , Aplasia Pura de Série Vermelha/sangue , Aplasia Pura de Série Vermelha/diagnóstico , Quimeras de Transplante
4.
Transplantation ; 72(4): 720-6, 2001 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-11544437

RESUMO

BACKGROUND: Polymorphisms in the regulatory regions of cytokine genes affect protein production and are associated with allograft outcome. Ethnic origin has been identified as a significant prognostic factor for several immune-mediated diseases and for outcome after allotransplantation. A clear relationship between cytokine polymorphisms and ethnicity has not been shown. METHODS: One hundred sixty subjects including 102 whites and 43 African-Americans were studied. Using polymerase chain reaction-based assays and, in some cases, restriction enzyme digestion, we determined genetic polymorphisms for the cytokines interleukin (IL) -2, IL-6, IL-10, tumor necrosis factor-alpha, transforming growth factor-beta, and interferon-gamma (IFN-gamma). Genetic polymorphism frequencies were then compared to ethnicity using chi-square analysis and Fisher's exact two-tailed tests. RESULTS: For both the IL-2 and IL-6 genes, we found that whites and African-Americans differed significantly (P <0.05) in their allelic distribution and genotype frequency. A trend toward ethnic distribution was noted among the alleles and genotypes for the IL-10 and IFN-gamma genes. We found no correlation between ethnicity and either allelic distribution or genotype frequency for the tumor necrosis factor-alpha or transforming growth factor-beta genes. When comparisons were made between patients with or without a history of kidney failure, the allelic or genotypic distributions for the IL-6 and IFN-gamma genes were found to significantly differ. CONCLUSIONS: Our work demonstrates a correlation between ethnicity and polymorphisms in several cytokine genes. In addition, we found that patients requiring renal transplantation differ from the general population with regard to certain cytokine gene polymorphisms. These findings may have relevance in making prognostic determinations or tailoring immunomodulatory regimens after renal transplantation.


Assuntos
População Negra/genética , Citocinas/genética , Interleucina-2/genética , Interleucina-6/genética , Polimorfismo Genético , População Branca/genética , Negro ou Afro-Americano , Alelos , Feminino , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Humanos , Falência Renal Crônica/genética , Masculino
5.
Am J Physiol Cell Physiol ; 281(2): C544-54, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11443053

RESUMO

Expression of endothelial nitric oxide synthase (eNOS) in transfected U-937 cells upregulates phorbol 12-myristate 13-acetate (PMA)-induced tumor necrosis factor-alpha (TNF-alpha) production through a superoxide (O(2)(-))-dependent mechanism. Because mitogen-activated protein kinases (MAPK) have been shown to participate in both reactive oxygen species signaling and TNF-alpha regulation, their possible role in eNOS-derived O(2)(-) signal transduction was examined. A redox-cycling agent, phenazine methosulfate, was found to both upregulate TNF-alpha (5.8 +/- 1.0 fold; P = 0.01) and increase the phosphorylation state of p42/44 MAPK (3.1 +/- 0.2 fold; P = 0.01) in PMA-differentiated U-937 cells. Although S-nitroso-N-acetylpenicillamine, a nitric oxide (NO) donor, also increased TNF-alpha production, NO exposure led to phosphorylation of p38 MAPK, not p42/44 MAPK. Upregulation of TNF-alpha production by eNOS transfection was associated with increases in activated p42/44 MAPK (P = 0.001), whereas levels of phosphorylated p38 MAPK were unaffected. Furthermore, cotransfection with Cu/Zn superoxide dismutase, which blocks TNF-alpha upregulation by eNOS, also abolished the effects on p42/44 MAPK. Expression of Gln(361)eNOS, a mutant that produces O(2)(-) but not NO, still resulted in p42/44 MAPK phosphorylation. In contrast, two NADPH binding site deletion mutants of eNOS that lack oxidase activity had no effect on p42/44 MAPK. Finally, PD-98059, a p42/44 MAPK pathway inhibitor, blocked TNF-alpha upregulation by eNOS (P = 0.02). Thus O(2)(-) produced by eNOS increases TNF-alpha production via a mechanism that involves p42/44 MAPK activation.


Assuntos
Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Óxido Nítrico Sintase/fisiologia , Transdução de Sinais/fisiologia , Superóxidos/metabolismo , Arginina/metabolismo , Sítios de Ligação/genética , Linhagem Celular , Ativação Enzimática/fisiologia , Deleção de Genes , Humanos , Metilfenazônio Metossulfato/farmacologia , Proteína Quinase 3 Ativada por Mitógeno , Mutação/fisiologia , N-Formilmetionina Leucil-Fenilalanina/farmacologia , NADP/metabolismo , Óxido Nítrico Sintase Tipo III , Oxirredução/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Explosão Respiratória/fisiologia , Fator de Necrose Tumoral alfa/metabolismo
6.
J Biol Chem ; 275(22): 16899-903, 2000 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-10747895

RESUMO

Reactive oxygen species can function as intracellular messengers, but linking these signaling events with specific enzymes has been difficult. Purified endothelial nitric-oxide synthase (eNOS) can generate superoxide (O(2)) under special conditions but is only known to participate in cell signaling through NO. Here we show that eNOS regulates tumor necrosis factor alpha (TNFalpha) through a mechanism dependent on the production of O(2) and completely independent of NO. Expression of eNOS in transfected U937 cells increased phorbol 12-myristate 13-acetate-induced TNFalpha promoter activity and TNFalpha production. N(omega)-Methyl-l-arginine, an inhibitor of eNOS that blocks NO production but not its NADPH oxidase activity, did not prevent TNFalpha up-regulation. Likewise, Gln(361)eNOS, a competent NADPH oxidase that lacks NOS activity, retained the ability to increase TNFalpha. Similar to the effect of eNOS, a O(2) donor dose-dependently increased TNFalpha production in differentiated U937 cells. In contrast, cotransfection of superoxide dismutase with eNOS prevented TNFalpha up-regulation, as did partial deletion of the eNOS NADPH binding site, a mutation associated with loss of O(2) production. Thus, eNOS may straddle a bifurcating pathway that can lead to the formation of either NO or O(2), interrelated but often opposing free radical messengers. This arrangement has possible implications for atherosclerosis and septic shock where endothelial dysfunction results from imbalances in NO and O(2) production.


Assuntos
Óxido Nítrico Sintase/metabolismo , Espécies Reativas de Oxigênio , Transdução de Sinais , Superóxidos/metabolismo , Sítios de Ligação , Glicina/química , Glicina/metabolismo , Humanos , NADP/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/química , Óxido Nítrico Sintase Tipo III , Deleção de Sequência , Fator de Necrose Tumoral alfa/metabolismo , Células U937
7.
Medicine (Baltimore) ; 79(1): 9-26, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10670406

RESUMO

Systematic review of the available information with a modified, largely quantitative method of research synthesis disclosed that an initial trial of thyroid hormone suppression therapy leads to clinically significant (> or = 50%) reduction of nodule size or arrest of nodule growth in a subset of patients with benign solitary thyroid nodules. In fact, in addition to objective improvements due to decreasing nodule size, L-T4 suppression therapy may benefit patients by reducing perinodular thyroid volume. Consequently, both pressure symptoms and cosmetic complaints may improve (9, 68). Additional studies for the assessment of the risks versus benefits of supraphysiologic doses of L-T4, the optimal level of thyroid suppression and the dose needed to achieve this magnitude of reduction, the optimal length of the initial trial, and the conditions for the continuation of L-T4 thyroid suppression therapy, as well as the identification of markers for patients most likely to respond to this therapy, are warranted. Finally, quantitative assessment of available evidence as described here may be applicable to the review of other controversial issues as well.


Assuntos
Antitireóideos/administração & dosagem , Nódulo da Glândula Tireoide/tratamento farmacológico , Adulto , Ensaios Clínicos como Assunto , Conferências para Desenvolvimento de Consenso de NIH como Assunto , Humanos , Pesquisa , Tiroxina/antagonistas & inibidores , Estados Unidos
8.
J Biol Chem ; 274(47): 33190-3, 1999 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-10559188

RESUMO

Regulation of gene transcription is an incompletely understood function of nitric oxide (NO). Human leukocytes produce increased amounts of tumor necrosis factor alpha (TNF-alpha) in response to NO. This effect is associated with decreases in intracellular cAMP, suggesting that NO might regulate gene transcription through promoter sequences sensitive to cAMP such as cAMP response elements (CRE) and Sp1 binding sites. Here we report that a Sp1 binding site in the TNF-alpha promoter conveys NO responsiveness. Human U937 cells were differentiated for TNF-alpha production with phorbol 12-myristate 13-acetate. NO donors and H89, an inhibitor of cAMP-dependent protein kinase increased, while dibutyryl cAMP (Bt(2)cAMP) decreased TNF-alpha promoter activity. Deletion or mutation of the proximal Sp1 site, but not the CRE site, abolished the activating effects of NO donors and H89. Further, NO- and H89-mediated increases in TNF-alpha promoter activity were associated with decreased Sp1 binding. The insertion of Sp1 sites into a minimal cytomegalovirus promoter conferred NO responsiveness, an effect blocked by Bt(2)cAMP. Mutation of these inserted Sp1 sites prevented this heterologous promoter from responding to NO, H89 and Bt(2)cAMP. These results identify the Sp1 binding site as a promoter motif that allows NO to control gene transcription.


Assuntos
Óxido Nítrico/metabolismo , Regiões Promotoras Genéticas , Fator de Transcrição Sp1/metabolismo , Fator de Necrose Tumoral alfa/genética , Sequência de Bases , Sítios de Ligação , Proteínas Quinases Dependentes de AMP Cíclico/antagonistas & inibidores , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , DNA/metabolismo , Primers do DNA , Ativação Enzimática , Humanos , Mutagênese Sítio-Dirigida , Óxido Nítrico/fisiologia , Ligação Proteica , Fator de Transcrição Sp1/genética , Fator de Necrose Tumoral alfa/fisiologia , Células U937
9.
J Leukoc Biol ; 64(4): 511-8, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9766632

RESUMO

Interleukin-8 (IL-8) priming was studied in neutrophils to examine its dependency on altered calcium fluxes and for similarity to lipopolysaccharide (LPS). IL-8 caused a rapid rise in [Ca2+]i that returned to baseline values by 20 min. Peak [Ca2+]i transients in response to N-formyl-methionyl-leucyl-phenylalanine (fMLP) were unaltered in IL-8-primed compared with unprimed cells. In comparison to LPS and tumor necrosis factor (TNF), IL-8 was a much weaker priming agent as measured by either O2- or H2O2 production. Despite their large disparity in potency, IL-8 and LPS printing were additive using fMLP, a receptor-dependent stimulator, and synergistic using the post-receptor, protein kinase C activator, phorbol 12-myristate 13-acetate (PMA) to trigger the respiratory burst. In contrast, IL-8 and TNF priming were synergistic for fMLP (P = 0.05), but completely nonadditive when PMA was used as the neutrophil stimulant (P = 0.05 for subadditivity). Thus, lasting alterations in [Ca2+]i are not a necessary characteristic of IL-8-primed cells. IL-8 and LPS appear to prime by non-overlapping pathways, whereas IL-8 and TNF appear to share mechanisms distal to protein kinase C activation. IL-8 and LPS may independently contribute to neutrophil-mediated host defense or injury by priming through distinct pathways.


Assuntos
Cálcio/sangue , Interleucina-8/farmacologia , Lipopolissacarídeos/farmacologia , Neutrófilos/fisiologia , Explosão Respiratória/fisiologia , Análise de Variância , Complemento C5a/farmacologia , Relação Dose-Resposta a Droga , Interações Medicamentosas , Sinergismo Farmacológico , Humanos , Peróxido de Hidrogênio/sangue , Técnicas In Vitro , Cinética , Medições Luminescentes , N-Formilmetionina Leucil-Fenilalanina/farmacologia , Neutrófilos/efeitos dos fármacos , Explosão Respiratória/efeitos dos fármacos , Superóxidos/sangue , Acetato de Tetradecanoilforbol/farmacologia , Fator de Necrose Tumoral alfa/farmacologia
10.
J Infect Dis ; 177(1): 116-26, 1998 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9419178

RESUMO

The effects of nitric oxide (NO) on human neutrophil chemotactic responses and release of interleukin (IL)-8 was studied. Neutrophils exposed to chemoattractants (IL-8, FMLP, leukotriene B4, and C5a) failed to show increases in intracellular guanosine 3',5'-cyclic monophosphate (cGMP), an indicator of NO production. Although NO increased cGMP in neutrophils, neither of two NO donors (sodium nitroprusside and 3-morpholino-sydonimine) nor a NO synthase inhibitor (N omega-nitro-L-arginine) altered FMLP- or IL-8-elicited neutrophil chemotaxis (P > .25 for all). However, lipopolysaccharide-induced IL-8 production was increased in a dose-dependent manner by a combination of sodium nitroprusside and N-acetylcysteine (P = .03) or by S-nitrosoglutathione (P = .004). NO-augmented IL-8 release was not reproduced by treating neutrophils with dibutyryl-cGMP. Up-regulation of IL-8 release by NO was associated with increased IL-8 mRNA levels (P = .009). These data suggest that NO does not directly affect neutrophil chemotaxis but may indirectly alter chemotactic responses by increasing IL-8 production via a cGMP-independent pathway.


Assuntos
Quimiotaxia , Interleucina-8/metabolismo , Neutrófilos/metabolismo , Óxido Nítrico/metabolismo , Acetilcisteína/farmacologia , Células Cultivadas , Complemento C5a/farmacologia , GMP Cíclico/metabolismo , Dibutiril GMP Cíclico/farmacologia , Relação Dose-Resposta a Droga , Ferricianetos/farmacologia , Glutationa/análogos & derivados , Glutationa/farmacologia , Humanos , Interleucina-8/farmacologia , Leucotrieno B4/farmacologia , Lipopolissacarídeos/farmacologia , Molsidomina/análogos & derivados , Molsidomina/farmacologia , N-Formilmetionina Leucil-Fenilalanina/farmacologia , Óxido Nítrico Sintase/metabolismo , Nitroprussiato/farmacologia , Compostos Nitrosos/farmacologia , RNA Mensageiro/metabolismo , S-Nitrosoglutationa , Regulação para Cima , ômega-N-Metilarginina/farmacologia
11.
Blood ; 90(3): 1160-7, 1997 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-9242548

RESUMO

Various functions of human phagocytes are modulated by nitric oxide (NO). We transfected the human U937 monoblastoid cell line with an expression vector containing human endothelial NO synthase (eNOS) or murine inducible NOS (iNOS) cDNA to study the regulatory role of NO without the nonspecific effects associated with exogenous NO sources. Western blot confirmed expression of eNOS or iNOS in respectively transfected cells, but not in naive or empty-vector transfected cells. Transfectants expressing iNOS, a calcium-independent enzyme, but not eNOS, a calcium-dependent enzyme, spontaneously produced NO (P < .001). The NO release from iNOS-transfected cells, as measured by nitrite and nitrate accumulation and by cyclic guanosine monophosphate (cGMP) increases in rat reporter cells, was inhibitable (P < .01 for both) with N(omega)-methyl-L-arginine (L-NMA), a NOS inhibitor. The eNOS transfectants were shown to contain functional enzyme by the conversion of L-arginine to L-citrulline in fractionated cells (P = .0001) and by exposing intact cells to calcium ionophore using the cGMP reporter cell assay (P = .0001). After differentiation with phorbol-12-myristate-13-acetate (PMA), iNOS transfectants produced more tumor necrosis factor-alpha (TNF-alpha) (124.9 +/- 25.4 pg/5 x 10(5) cells per 24 hours) than did empty-vector transfected cells (21.9 +/- 1.9 pg/5 x 10(5) cells per 24 hours; P = .02). This effect was inhibited by 500 micromol/L L-NMA (54.4 +/- 3.1 pg/5 x 10(5) cells per 24 hours; P = .05). However, in the presence of high concentrations of lipopolysaccharide (1 microg/mL), which further increased NO production in iNOS transfected cells (P = .044), TNF-alpha production was similar comparing PMA-differentiated iNOS and empty-vector transfectants (12.2 +/- 0.8 and 13.1 +/- 1.7 ng/5 x 10(5) cells per 24 hours, respectively; P = .5). The results show that under certain conditions endogenously produced NO can upregulate TNF-alpha production in human phagocytes.


Assuntos
Regulação Neoplásica da Expressão Gênica , Linfoma Difuso de Grandes Células B/patologia , Proteínas de Neoplasias/biossíntese , Óxido Nítrico/fisiologia , Fator de Necrose Tumoral alfa/biossíntese , Animais , Arginina/metabolismo , Diferenciação Celular/efeitos dos fármacos , Citrulina/metabolismo , GMP Cíclico/fisiologia , DNA Complementar/genética , Indução Enzimática/efeitos dos fármacos , Vetores Genéticos , Humanos , Camundongos , Proteínas de Neoplasias/genética , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase/metabolismo , Ratos , Proteínas Recombinantes de Fusão/metabolismo , Sistemas do Segundo Mensageiro/fisiologia , Acetato de Tetradecanoilforbol/farmacologia , Transfecção , Células Tumorais Cultivadas , Fator de Necrose Tumoral alfa/genética , ômega-N-Metilarginina/farmacologia
12.
J Biol Chem ; 272(9): 5959-65, 1997 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-9038216

RESUMO

Nitric oxide (NO) increases tumor necrosis factor (TNF) synthesis in human peripheral blood mononuclear cells by a cGMP-independent mechanism. NO has been shown to inhibit adenylate cyclase in cell membranes. Since cAMP down-regulates TNF transcription, we examined the possibility that NO enhances TNF synthesis by decreasing cAMP. U937 cells were induced to differentiate using phorbol myristate acetate (100 nM for 48 h) and then were incubated for 24 h with sodium nitroprusside (SNP) or S-nitroso-N-acetylpenicillamine (SNAP). These NO donors increased TNF production (7.0- and 15.6-fold, respectively, at 500 microM) in a dose-dependent manner (p = 0.002). However, SNP and SNAP did not elevate cGMP levels in U937 cell cultures, and the cGMP analog, 8-bromo-cGMP, had no effect on TNF production. In contrast, SNP (p = 0.001) and SNAP (p = 0.009) decreased intracellular cAMP levels by up to 51.5% over 24 h and, in the presence of a phosphodiesterase inhibitor, blunted isoproterenol-stimulated increases in cAMP by 21.8% (p = 0.004) and 27.6% (p = 0.008), respectively. H89, an inhibitor of cAMP-dependent protein kinase, dose dependently increased TNF production in phorbol myristate acetate-differentiated U937 cells in the absence (6.5-fold at 30 microM; p = 0.035), but not in the presence (p = 0.77) of SNAP. Conversely, the cAMP analog dibutyryl cAMP (Bt2cAMP) blocked SNAP-induced TNF production (p = 0.001). SNP and SNAP (500 microM) increased relative TNF mRNA levels by 57.5% (p = 0.045) and 66.2% (p = 0.001), respectively. This effect was prevented by Bt2cAMP. These results indicate that NO up-regulates TNF production by decreasing intracellular cAMP.


Assuntos
AMP Cíclico/metabolismo , Óxido Nítrico/farmacologia , Fator de Necrose Tumoral alfa/biossíntese , Bucladesina/farmacologia , Diferenciação Celular , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , GMP Cíclico/análogos & derivados , GMP Cíclico/farmacologia , Humanos , Penicilamina/análogos & derivados , Penicilamina/farmacologia , RNA Mensageiro/metabolismo , S-Nitroso-N-Acetilpenicilamina , Acetato de Tetradecanoilforbol/farmacologia , Vasodilatadores/farmacologia
13.
Pharmacotherapy ; 16(6): 1103-10, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8947984

RESUMO

We conducted a prospective, randomized, controlled trial to assess whether hospital formulary restrictions involving limiting dosage strengths of levothyroxine affect physicians' ability to manage patients effectively and provide pharmacy cost savings in a tertiary care federal government research hospital. Thirty-three endocrinologists were randomly assigned to prescribe levothyroxine from a restrictive (dosage strengths of 25, 50, 100, 125, and 150 micrograms) or a nonrestrictive (dosage strengths of 25, 50, 75, 100, 112, 125, 150, 175, 200, and 300 micrograms) formulary through a central computer system. Their 241 respective outpatients' laboratory results and drug compliance were outcome measures. Achievement of treatment objectives was measured by thyroid function tests (free and total thyroxine, total triiodothyronine, thyrotropin), number of clinic visits, and compliance (survey method). Additional measures were drug distribution patterns, drug costs, and pharmacy inventory costs. Restriction of levothyroxine's dosage strength did not significantly alter therapeutic outcomes. However, the restricted formulary was associated with more complex dosing regimens, and resulted in no significant cost savings. It is not known whether such restriction would adversely affect the care of patients of nonspecialists. Prospective studies are required to verify presumed cost-containment measures before such measures are adopted for widespread application.


Assuntos
Hospitais Federais/economia , Padrões de Prática Médica/economia , Doenças da Glândula Tireoide/tratamento farmacológico , Tiroxina/administração & dosagem , Tiroxina/economia , Adulto , Controle de Custos , Feminino , Formulários de Hospitais como Assunto , Humanos , Masculino , Maryland , Pessoa de Meia-Idade , National Institutes of Health (U.S.) , Cooperação do Paciente , Estudos Prospectivos , Estados Unidos
14.
J Immunol ; 152(8): 4102-9, 1994 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-8144975

RESUMO

We studied the effect of nitric oxide on LPS-induced TNF-alpha production by human neutrophils. Human neutrophils exposed to LPS and IFN-gamma did not show measurable increases in intracellular cyclic GMP (cGMP). However, cGMP increased upto 30-fold (p < 0.01) in neutrophils incubated with both sodium nitroprusside (SNP), an exogenous source of nitric oxide, and N-acetylcysteine (NAC), which increases the bioavailability of nitric oxide; this increase indicates that neutrophils contain a nitric oxide-sensitive guanylate cyclase. SNP, with or without NAC, did not increase TNF-alpha production in human neutrophils cultured in medium alone. However, LPS-dependent TNF-alpha production was increased by exposure to SNP (p < 0.05); this effect was further increased by the addition of NAC (p < 0.02). IFN-gamma greatly increased LPS-mediated TNF-alpha production by human neutrophils (p < 0.01), and SNP plus NAC was found to further augment this production (p < 0.01). The up-regulation of TNF-alpha production by nitric oxide was not associated with increased amounts of LPS-induced TNF-alpha mRNA, and was not reproduced by exposing neutrophils to cGMP analogues. These data suggest that nitric oxide released by endothelial and vascular smooth muscle cells may exert a paracrine effect on human neutrophils and augment the inflammatory response in sepsis by increasing the production of cytokines. Although the mechanism of this effect remains unknown, it does not seem to be dependent on cGMP or increased levels of TNF-alpha mRNA.


Assuntos
Neutrófilos/metabolismo , Óxido Nítrico/farmacologia , Fator de Necrose Tumoral alfa/biossíntese , Acetilcisteína/farmacologia , GMP Cíclico/metabolismo , Expressão Gênica/efeitos dos fármacos , Humanos , Técnicas In Vitro , Interferon gama/farmacologia , Lipopolissacarídeos/farmacologia , Macrófagos/metabolismo , Neutrófilos/efeitos dos fármacos , Nitroprussiato/farmacologia , RNA Mensageiro/genética , Fator de Necrose Tumoral alfa/genética
15.
Arch Pathol Lab Med ; 116(8): 847-55, 1992 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-1497467

RESUMO

We classified 159 cases of rhabdomyosarcoma (RMS) according to the conventional scheme adopted by the World Health Organization and a modified conventional scheme established at the National Cancer Institute (NCI), Bethesda, Md. The major modification in the NCI scheme was the inclusion of compact round-cell RMS with scant myogenesis in the group of alveolar RMS despite lack of an alveolar architecture. These tumors were previously considered to be embryonal RMS, but their cytologic features are quite different from those seen in embryonal RMS and are indistinguishable from those encountered in alveolar RMS. These tumors are referred to as "solid alveolar RMS." Survival curves were constructed with the method of Kaplan-Meier and compared with the unstratified and stratified methods of Mantel-Haenszel (with stratification factors being stage, site, and age) and with the Cox regression analysis. Both histologic schemes showed a statistically significant prognostic value in unstratified analyses, but the NCI scheme demonstrated prognostic value even in stratified analyses and in the Cox regression analysis in our series of cases. The data indicate that the NCI scheme can serve as a highly predictive, independent prognostic factor in RMS and that the alveolar category should be expanded to include the solid round-cell RMS, even in the absence of a classic alveolar architecture.


Assuntos
Rabdomiossarcoma/classificação , Adolescente , Criança , Pré-Escolar , Humanos , Lactente , Análise Multivariada , National Institutes of Health (U.S.) , Prognóstico , Análise de Regressão , Rabdomiossarcoma/patologia , Estatística como Assunto , Estados Unidos , Organização Mundial da Saúde
16.
Chest ; 99(1): 169-75, 1991 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-1984950

RESUMO

To evaluate the incidence, pattern and clinical importance of endotoxemia in septic shock, frequent, serial endotoxin determinations were made prospectively in patients with shock. Detectable endotoxin occurred in 43 of 100 patients with septic shock, but in only one of ten patients with shock due to nonseptic causes. During septic shock, endotoxemia frequently occurred in the absence of Gram-negative bacteremia. Using a logistic regression model, multiple organ failure occurred 10.3 times more frequently and depression of left ventricular ejection fraction (less than or equal to 45 percent) 4.8 times more frequently in endotoxemic patients. In patients with positive blood cultures, endotoxemia was associated with a high mortality. We conclude that endotoxemia occurs frequently in septic shock and is associated with severe manifestations of this syndrome, including cardiac depression and multiple organ failure. This study suggests that endotoxin is an important mediator of septic shock and supports efforts to develop anti-endotoxin therapies for treating patients with this disease.


Assuntos
Infecções Bacterianas/sangue , Endotoxinas/sangue , Bactérias Gram-Negativas , Choque Séptico/sangue , Infecções Bacterianas/mortalidade , Feminino , Humanos , Incidência , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Insuficiência de Múltiplos Órgãos/mortalidade , Análise Multivariada , Estudos Prospectivos , Choque/sangue , Choque Séptico/mortalidade , Função Ventricular Esquerda/fisiologia
17.
Infect Control Hosp Epidemiol ; 11(7): 351-6, 1990 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-2376660

RESUMO

An anonymous national survey of a representative population of healthcare workers who were thought likely to have frequent and intensive exposures to blood and other body fluids (certified nurse-midwives [CNMs]), was conducted to assess the type and frequency of self-reported occupational exposures to blood and body fluids experienced, the extent to which barrier precautions and other infection control measures were used, whether or not reported use of barriers was associated with a lower perceived rate of exposures and factors that influenced the use of infection control procedures. Of those responding, 74% had soiled their hands with blood at least one time in the preceding six months, 51% had splashed blood or amniotic fluid in their faces and 24% reported one or more needlestick injuries during that same period. Our study also found evidence of an association between the practice of needle recapping and the occurrence of needlestick injury (p = .003). Despite a high level of training and knowledge, only 55% reported routinely practicing universal precautions (UPs). Several factors that potentially influenced the use of UPs were studied, including healthcare worker perceptions of risk of occupational bloodborne infection, knowledge of routes of transmission of bloodborne pathogens and rationale for not using appropriate barriers. Our data suggest that occupational exposures occur frequently and that healthcare workers' (HCWs') perceptions of risk for occupational infection play an important role in influencing use of UPs. This study emphasizes the importance of developing new strategies for UP training.


Assuntos
Síndrome da Imunodeficiência Adquirida/prevenção & controle , Exposição Ambiental , Conhecimentos, Atitudes e Prática em Saúde , Hepatite B/prevenção & controle , Enfermeiros Obstétricos , Síndrome da Imunodeficiência Adquirida/transmissão , Certificação , Hepatite B/transmissão , Humanos , Fatores de Risco , Inquéritos e Questionários
18.
J Nurse Midwifery ; 34(6): 309-17, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2614519

RESUMO

A questionnaire was designed with these objectives: (1) to determine the frequency and type of adverse exposures experienced by certified nurse-midwives (CNMs); (2) to determine the extent to which CNMs used recommended precautions to prevent such incidents; and (3) to identify the sources used for obtaining information on AIDS. The questionnaire was mailed to all CNMs with the exception of associate and student members of the American College of Midwives. A response rate of 1,784/2,963 (60.2%) was obtained. These midwives reported frequent exposures to blood and body fluids. Sixty-five percent reported being soaked to the skin with blood or amniotic fluid; 50.7% had face-splashes with blood or amniotic fluid; and 24.0% experienced one or more needlestick(s). Only 55.1% reported using Universal Precautions (UP). Interference with the midwife-client relationship was identified most frequently as the reason for not using UP. Strategies need to be developed for midwives that will increase the use of UP and minimize the frequency of adverse exposures, while maintaining a caring midwife-client relationship.


Assuntos
Síndrome da Imunodeficiência Adquirida/prevenção & controle , Exposição Ambiental , Enfermeiros Obstétricos/estatística & dados numéricos , Síndrome da Imunodeficiência Adquirida/transmissão , Atitude do Pessoal de Saúde , Desinfecção das Mãos , Humanos , Agulhas , Roupa de Proteção/estatística & dados numéricos , Inquéritos e Questionários , Estados Unidos
19.
N Engl J Med ; 321(5): 280-7, 1989 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-2664516

RESUMO

Marked abnormalities in cardiovascular function accompany septic shock, and bacterial endotoxin is believed to be one of the principal mediators of these abnormalities. To evaluate the cardiovascular effects of endotoxemia in humans, we measured hemodynamic variables in nine normal subjects given an intravenous bolus dose of endotoxin (Escherichia coli, 4 ng per kilogram of body weight) and in six normal subjects given a bolus dose of saline, before and three hours after administration. All the subjects then underwent volume loading with normal saline (mean, 2217 ml) during the fourth and fifth hours after administration of the bolus, and the measurements were repeated. Three hours after the administration of endotoxin and before volume loading, the cardiac index had increased by 53 percent and the heart rate by 36 percent (both changes were significant; P less than or equal to 0.008), and the systemic vascular-resistance index had decreased by 46 percent (P = 0.004). After volume loading (five hours after the administration of endotoxin), the left ventricular ejection fraction decreased by 1 percent of the base-line value in the subjects given endotoxin, but increased by 14 percent in the controls (P = 0.008). The left ventricular end-diastolic and end-systolic volume indexes increased by 18 percent (P = 0.07) and 24 percent (P = 0.042), respectively. Left ventricular performance, as measured by the ratio of the peak systolic pressure to the end-systolic volume index, was depressed (a decrease of 0.90 in the subjects given endotoxin vs. an increase of 0.76 in the controls; P = 0.024). We conclude that the administration of endotoxin to normal subjects causes a depression of left ventricular function that is independent of changes in left ventricular volume or vascular resistance. The changes in function are similar to those observed in septic shock and suggest that endotoxin is a major mediator of the cardiovascular dysfunction in this condition.


Assuntos
Endotoxinas/toxicidade , Coração/efeitos dos fármacos , Hemodinâmica/efeitos dos fármacos , Adulto , Pressão Sanguínea/efeitos dos fármacos , Cálcio/sangue , Escherichia coli , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino , Choque Séptico/fisiopatologia , Volume Sistólico/efeitos dos fármacos , Toxemia/fisiopatologia , Fator de Necrose Tumoral alfa/análise , Resistência Vascular/efeitos dos fármacos
20.
Cell Immunol ; 104(2): 366-76, 1987 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-3493081

RESUMO

The control of malignancy disseminated within the peritoneal cavity is an important problem in the management of low-grade gastrointestinal and ovarian neoplasms. A model of peritoneal carcinomatosis in the mouse was used to investigate the potential of lymphokine-activated killer (LAK) cells and exogenous interleukin 2 (IL-2) to control intraperitoneal tumor. LAK cells are splenocytes activated in vitro by IL-2. C57BL/6 mice were injected intraperitoneally with a lethal inoculum of syngeneic MCA-105 tumor. Three days later, the established tumor was treated with adoptively transferred LAK cells and/or exogenous IL-2 administration. LAK cells alone were ineffective in reducing intraperitoneal tumor. Administration of IL-2 alone resulted in limited tumor reduction. Treatment with exogenous IL-2 in conjunction with LAK cells resulted in the greatest reduction of intraperitoneal tumor. The larger the number of LAK cells given, the greater the reduction in tumor. Frequent intraperitoneal bolus administration of IL-2 was more effective than a single daily intraperitoneal injection and intraperitoneal administration of IL-2 and LAK was more effective than systemic treatments. Marked prolongation of life was seen in mice treated with LAK cells plus exogenous IL-2. We conclude that intraperitoneal LAK cells plus exogenous IL-2 is an effective treatment regimen for reducing intraperitoneal tumor in this murine model.


Assuntos
Interleucina-2/uso terapêutico , Células Matadoras Naturais/imunologia , Linfocinas/imunologia , Neoplasias Peritoneais/terapia , Animais , Relação Dose-Resposta Imunológica , Esquema de Medicação , Imunoterapia , Interleucina-2/administração & dosagem , Camundongos
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