RESUMO
Objectives: The neutropenic murine thigh infection model and a dose-fractionation approach were used to determine the pharmacokinetic/pharmacodynamic (PK/PD) relationship of LYS228, a novel monobactam antibiotic with activity against Enterobacteriaceae including carbapenem-resistant strains. Methods: Mice (n = 4 per group) were inoculated with Enterobacteriaceae strains via intramuscular injection. Two hours post-bacterial inoculation, treatment with LYS228 was initiated. Animals were euthanized with CO2 24 h after the start of therapy and bacterial counts (log10 cfu) per thigh were determined. PK parameters were calculated using free (f) plasma drug levels. Results: Following a dose-fractionation study, non-linear regression analysis determined that the predominant PK/PD parameter associated with antibacterial efficacy of LYS228 was the percentage of the dosing interval that free drug concentrations remained above the MIC (%fT>MIC). In a dose-dependent manner, LYS228 reduced the thigh bacterial burden in models established with Enterobacteriaceae producing ß-lactamase enzymes of all classes (e.g. ESBLs, NDM-1, KPC, CMY-2 and OXA-48). The range of the calculated static dose was 86-649 mg/kg/day for the isolates tested, and the magnitude of the driver of efficacy was 37-83 %fT>MIC. %fT>MIC was confirmed as the parameter predominantly driving efficacy as evidenced by a strong coefficient of determination (r2 = 0.68). Neutrophils had minimal impact on the effect of LYS228 in the murine thigh infection model. Conclusions: LYS228 is efficacious in murine thigh infection models using ß-lactamase-producing strains of Enterobacteriaceae, including those expressing metallo-ß-lactamases, ESBLs and serine carbapenemases, with the PK/PD driver of efficacy identified as %T>MIC.
Assuntos
Infecções por Enterobacteriaceae/tratamento farmacológico , Enterobacteriaceae/efeitos dos fármacos , Monobactamas/farmacologia , Monobactamas/farmacocinética , Animais , Contagem de Colônia Microbiana , Modelos Animais de Doenças , Enterobacteriaceae/isolamento & purificação , Feminino , Injeções Intramusculares , Camundongos , Testes de Sensibilidade Microbiana , Monobactamas/administração & dosagem , Resultado do TratamentoRESUMO
Allograft rejection represents a cytotoxic response mediated to a large degree by thymus-derived T lymphocytes (1). The study of such cell-mediated cytotoxic phenomena has been greatly facilitated by the discovery first noted by Hayry and Defendi (2) and Wunderlich and Cany (3), that a natural consequence of allogeneic stimulation in an unidirectional mixed lymphocyte culture (MLC) was the appearance of cytotoxic lymphocytes specific for antigens present on the stimulator cells. Subsequent studies have shown that such in vitro generation of cytotoxic lymphocytes was dependent on the proliferative response in an MLC (4), was genetically determined (5), and possibly required the interaction of several subpopulations of T cells (6). We now report that the surface active agent chlorpromazine: (a) inhibits allogeneic stimulation of the proliferative response in an MLC; (b) inhibits the MLC generation of cytotoxic lymphocytes, (c) has no effect on the recognition, binding, or lysis of target cells by already sensitized lymphocytes; and (d) blocks a postproliferative membrane-mediated event, independent of proliferation, and necessary for the MLC generation of cytotoxic lymphocytes.
Assuntos
Clorpromazina/farmacologia , Linfócitos/efeitos dos fármacos , Animais , Testes Imunológicos de Citotoxicidade , Depressão Química , Feminino , Ativação Linfocitária , Linfócitos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos , Fatores de TempoRESUMO
A metabolic pathway by which L-arginine (L-arg) is converted to the biologically active compound NO. has recently been described in macrophages (M phi) and endothelial cells. This report demonstrates that transferable products from activated Kupffer cells (KC) induce the conversion of large quantities of L-arg to nitrogen oxides within hepatocytes (HC). In M phi and endothelial cells, citrulline and NO2-/NO3- are the stable endproducts of this metabolic pathway. In contrast, HC L-arg metabolism resulted in significantly greater production of NO2-/NO3- than citrulline. The generation of NO. within HC was associated with a concurrent decrease in total protein synthesis.
Assuntos
Arginina/metabolismo , Inflamação/metabolismo , Células de Kupffer/fisiologia , Fígado/metabolismo , Óxidos de Nitrogênio/metabolismo , Animais , Células Cultivadas , Ferredoxinas/metabolismo , Técnicas In Vitro , Interferon gama/farmacologia , Lipopolissacarídeos/farmacologia , Biossíntese de Proteínas , Ratos , Fatores de TempoRESUMO
The hepatic failure associated with severe sepsis is characterized by specific, progressive, and often irreversible defects in hepatocellular metabolism (1). Although the etiologic microbe can often be identified, the direct causes and mechanisms of the hepatocellular dysfunction are poorly understood. We have hypothesized that Kupffer cells (KC), which interact with ambient septic stimuli, respond by providing signals to adjacent hepatocytes (HC) in sepsis . Furthermore, we have provided evidence (2, 3) that KC activated by LPS from Gram-negative bacteria can induce profound changes in the function of neighboring HC in coculture. In our model, coculture of either KC (2) or peritoneal macrophages (Mphi)(3) with HC normally promotes HC protein synthesis ([(3)H]leucine incorporation). The addition of LPS or killed Escherichia colt' to such cocultures induces a profound decrease in HC protein synthesis, as well as qualitative changes ([(35)S]methionine, SDS-gel electrophoresis) in protein synthesis without inducing HC death (2, 3) . In this report we show that the inhibition in protein synthesis is mediated via an L-arginine-dependent mechanism. The metabolism of L-arginine by activated Mphi to substances with cytostatic and even lethal effects on target cells is a relatively recent discovery. After the description by Stuehr and Marletta (4, 5) that LPS- triggered Mphi produced nitrite/nitrate (NO(2)(-)/NO(3)(-)), Hibbs et al. (6, 7) and Iyengar et al. (8) demonstrated that L-arginine was the substrate for the formation of both these nitrogen end products and citrulline. A role for the arginine-dependent mechanism in Mphi tumor cytotoxicity (6, 7) and microbiostatic activity (9) has been suggested. However, the in vivo functions of this novel Mphi mechanism have not yet been defined, but it is possible that there are both physiologic as well as pathologic roles. Our in vitro results raise the possibility that some metabolic responses to microbial invasion maybe partially mediated by the L-arginine-dependent mechanism. What other metabolic responses are affected and the possible pathologic consequences remain to be studied.
Assuntos
Arginina/farmacologia , Células de Kupffer/fisiologia , Fígado/fisiologia , Biossíntese de Proteínas , Animais , Citrulina/metabolismo , Técnicas In Vitro , Lipopolissacarídeos/farmacologia , Nitratos/metabolismo , Nitritos/metabolismo , Ratos , Ratos EndogâmicosRESUMO
Nitric oxide (NO) is a short-lived biologic mediator that is shown to be induced in various cell types and to cause many metabolic changes in target cells. Inhibition of tumor cell growth and antimicrobial activity has been attributed to the stimulation of the inducible type of the NO synthase (NOS). However, there is limited evidence for the existence of such inducible NOS in a human cell type. We show here the induction of NO biosynthesis in freshly isolated human hepatocytes (HC) after stimulation with interleukin 1, tumor necrosis factor (TNF), IFN-gamma, and endotoxin. Increased levels of nitrite (NO2-) and nitrate (NO3-) in culture supernatants were associated with NADPH-dependent NOS activity in the cell lysates. The production of NO2- and NO3- was inhibited by NG-monomethyl L-arginine and was associated with an increase in cyclic guanylate monophosphate release. The data presented here provide evidence for the existence of typical inducible NO biosynthesis in a human cell type.
Assuntos
Aminoácido Oxirredutases/biossíntese , Citocinas/farmacologia , Endotoxinas/farmacologia , Lipopolissacarídeos , Fígado/enzimologia , Arginina/análogos & derivados , Arginina/farmacologia , GMP Cíclico/biossíntese , Humanos , Fígado/efeitos dos fármacos , Nitratos/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase , Nitritos/metabolismo , Proteínas Recombinantes/farmacologia , ômega-N-MetilargininaRESUMO
Firmly established methylcholanthrene fibrosarcomas in syngeneic mice will totally disappear if the hosts are treated with living tumor cells that have been exposed to Vibrio cholerae neuraminidase in vitro. The effect is magnified by the simultanieous injection of a nonspecific immunostimulant, BCG. The rejection of the methylcholanthrene tumor is immunospecific and can be induced only with tumor cells, treated with Vibrio cholerae neuraminidase, identical in type with the growing tumor.
Assuntos
Fibrossarcoma/terapia , Imunização , Mycobacterium bovis/imunologia , Neoplasias Experimentais/terapia , Neuraminidase/farmacologia , Animais , Formação de Anticorpos , Feminino , Fibrossarcoma/induzido quimicamente , Fibrossarcoma/imunologia , Rejeição de Enxerto , Metilcolantreno , Camundongos , Transplante de Neoplasias , Neoplasias Experimentais/imunologia , Neuraminidase/análise , Imunologia de Transplantes/efeitos dos fármacos , Transplante Homólogo , Vibrio/enzimologiaRESUMO
A sustained decrease of plasma bilirubin concentrations occurred in homozygous recessive Gunn rats lacking the enzyme uridine diphosphate glucuronyltransferase following infusion into the portal vein of hepatocytes from heterozygous nonjaundiced Gunn rats possessing the enzyme. Transplantation of cells capable of continuous enzyme production could be an effective mode of therapy for congenital enzyme deficiency diseases.
Assuntos
Modelos Animais de Doenças , Glucuronosiltransferase/deficiência , Hexosiltransferases/deficiência , Hiperbilirrubinemia Hereditária/cirurgia , Transplante de Fígado , Animais , Bilirrubina/sangue , Heterozigoto , Homozigoto , Ratos , Transplante HomólogoRESUMO
The direct effects of pro-inflammatory cytokines on the contractility of mammalian heart were studied. Tumor necrosis factor alpha, interleukin-6, and interleukin-2 inhibited contractility of isolated hamster papillary muscles in a concentration-dependent, reversible manner. The nitric oxide synthase inhibitor NG-monomethyl-L-arginine (L-NMMA) blocked these negative inotropic effects. L-Arginine reversed the inhibition by L-NMMA. Removal of the endocardial endothelium did not alter these responses. These findings demonstrate that the direct negative inotropic effect of cytokines is mediated through a myocardial nitric oxide synthase. The regulation of pro-inflammatory cytokines and myocardial nitric oxide synthase may provide new therapeutic strategies for the treatment of cardiac disease.
Assuntos
Citocinas/farmacologia , Contração Miocárdica/efeitos dos fármacos , Óxido Nítrico/farmacologia , Animais , Arginina/análogos & derivados , Arginina/farmacologia , Células Cultivadas , Cricetinae , Relação Dose-Resposta a Droga , Interações Medicamentosas , Endocárdio/citologia , Epitélio/fisiologia , Interleucina-2/farmacologia , Interleucina-6/farmacologia , Microscopia Eletrônica , Fator de Necrose Tumoral alfa/farmacologia , ômega-N-MetilargininaRESUMO
A horse immunized with dog lynmphocytes produced an antiserum which agglutinated canine lymphocytes in vitro and caused prolonged lymphopenia in dogs in vivo. Renal transplants in dogs treated with this antiserum survived for long periods, two of the grafts surviving beyond 350 days with normal function and histologic appearance.
Assuntos
Soros Imunes , Transplante de Rim , Linfócitos , Imunologia de Transplantes , Transplante Heterólogo , Aglutinação , Animais , Cães , LeucopeniaRESUMO
The present study was designed to determine whether .N = O produced in vivo during the rejection of histoincompatible tissues might permit serum NO2-/NO3- levels to serve as markers of a rejection reaction. Rat syngeneic and allogeneic liver, heart, bone marrow/spleen cell, small bowel, skin, and sponge matrix grafts were performed and the stable end-products of .N = O, NO2-/NO3-, were serially assayed in the serum of the grafted animals. A significant rise of serum NO2-/NO3- levels in the allografted animals preceded the onset of clinical signs of rejection or graft-versus-host disease, with the exception of the skin and sponge matrix graft models, where elevated serum NO2-/NO3- levels were never observed. In all transplant models, normal serum NO2-/NO3- levels were observed at all times in animals that received syngeneic grafts. Furthermore, treatment of allograft recipients with the immunosuppressive agents FK 506 or cyclosporine A inhibited .N = O production. Determination of serum creatinine levels demonstrated that the elevated serum NO2-/NO3- levels were not caused by kidney dysfunction. Serum NO2-/NO3- levels might be useful early serum markers of the initiation of a rejection reaction or graft-versus-host disease when functional markers of graft dysfunction are not apparent.
Assuntos
Reação Enxerto-Hospedeiro , Reação Hospedeiro-Enxerto , Óxido Nítrico/metabolismo , Animais , Transplante de Medula Óssea/imunologia , Ciclosporina/farmacologia , Transplante de Coração/imunologia , Imunossupressores/farmacologia , Intestino Delgado/imunologia , Intestino Delgado/transplante , Transplante de Fígado/imunologia , Ratos , Ratos Endogâmicos , Transplante de Pele/imunologia , Baço/imunologia , Baço/transplante , Tacrolimo/farmacologia , Fatores de TempoRESUMO
Neuraminidase from Vibrio cholerae (VCN) was used to treat sheep red blood cells (SRBC) which were then incubated in vitro with murine peritoneal macrophages. The uptake of VCN-treated SRBC by macrophages was greater than the uptake of SRBC not treated with VCN. SRBC opsonized with normal mouse serum (NMS) were taken up to a greater extent than untreated SRBC. SRBC treated with VCN and opsonized with NMS were phagocytosed to a greater extent than untreated SRBC, VCN-treated SRBC, or opsonized SRBC. Evidence demonstrated that factors in serum from normal C3H/HeJ mice augmented the uptake of VCN-treated SRBC in greater amounts than of normal SRBC. These findings were discussed in relation to the increased immunogenicity of neuraminidase-treated cells.
Assuntos
Eritrócitos/efeitos dos fármacos , Macrófagos/imunologia , Neuraminidase/farmacologia , Proteínas Opsonizantes , Fagocitose , Animais , Epitopos , Eritrócitos/imunologia , Feminino , Camundongos , Camundongos Endogâmicos C3H , Ovinos , Vibrio cholerae/enzimologiaRESUMO
The timing within the estrous cycle of surgical removal of a transplanted murine mammary tumor profoundly influences the frequency of pulmonary metastases. We investigated the potential role of the immune response in this phenomenon by measuring splenic natural killer (NK) cell activity and interleukin-2 (IL-2) production in syngeneic tumor-free mice of two age groups at each of two circadian times and in each of four estrous stages. Estrous stage was determined by assessment of vaginal smear cellularity immediately prior to killing and spleen harvest. In a single-cell splenocyte preparation, NK cytotoxicity against a standard tumor cell target was assessed using a radiolabeled chromium release assay while IL-2 activity was determined in a bioassay utilizing the IL-2-dependent CTLL-2 cell line. Mice from the younger group were found to have eight-fold higher NK activity and 35% greater IL-2 production. After normalization of NK and IL-2 values for age, a highly statistically significant difference in NK activity was found among the four estrous and between the two circadian stages of sacrifice. NK activity was greater during the daily resting span across every estrous stage. IL-2 values were highest in diestrus and proestrus when sampled in the light span and in estrus-metestrus when sampled in the dark. The stages within the fertility cycle associated with lowest metastatic potential (proestrus/estrus) correspond precisely with those of highest splenocyte NK activity. These results indicate that an important component of the cellular immune response varies rhythmically both during the fertility and circadian cycles of the host. The rhythmic changes in NK activity may be in part responsible for the similarly rhythmic frequency of postsurgical metastatic dissemination.
Assuntos
Estro , Células Matadoras Naturais/imunologia , Metástase Neoplásica , Fatores Etários , Animais , Ritmo Circadiano , Feminino , Interleucina-2/biossíntese , Camundongos , Camundongos Endogâmicos C3HRESUMO
BACKGROUND: Toxicity to interleukin-2 (IL-2) tumor immunotherapy is manifested principally by the vascular leak syndrome, hypotension, and a hyperdynamic response with low systemic vascular resistance. Nitric oxide (.N = O), a recently discovered biological mediator of vascular smooth muscle relaxation, is produced in increased amounts by numerous cell types exposed to a number of inflammatory cytokines. PURPOSE: Our purpose was to determine if there is an increased production of .N = O in patients receiving IL-2 tumor immunotherapy, and, if so, whether increases in .N = O production correlate with hemodynamic instability. METHODS: Twelve patients undergoing immunotherapy trials with IL-2 and anti-CD3 monoclonal antibody-activated lymphocytes (T-AK cells) were studied. Plasma levels of nitrate (NO3-), the stable end metabolic product of .N = O synthesis, were measured before and at the end of IL-2 treatment cycles. RESULTS: We observed a ninefold increase in plasma levels of NO3- in patients after 7 days of treatment (P less than .0001). A significant decrease in both systolic and diastolic blood pressures was observed in all patients (P less than .001). CONCLUSIONS: We propose that mediated induction of .N = O synthase enzyme leads to progressive increases in .N = O production which, in turn, produces clinically significant hypotension. IMPLICATIONS: Since .N = O synthesis can be competitively inhibited by L-arginine analogues, a possible pharmacologic modulation of .N = O production could potentially contribute to better management of toxic side effects seen in IL-2 cancer therapies.
Assuntos
Antígenos de Diferenciação de Linfócitos T/imunologia , Pressão Sanguínea/efeitos dos fármacos , Imunoterapia , Interleucina-2/efeitos adversos , Linfócitos/imunologia , Neoplasias/terapia , Óxido Nítrico/sangue , Óxidos de Nitrogênio/sangue , Receptores de Antígenos de Linfócitos T/imunologia , Aminoácido Oxirredutases/biossíntese , Anticorpos Monoclonais/uso terapêutico , Antígenos CD/imunologia , Biomarcadores/sangue , Complexo CD3 , Indução Enzimática , Feminino , Radicais Livres/sangue , Humanos , Hipotensão/etiologia , Infusões Intravenosas , Injeções Intravenosas , Interleucina-2/administração & dosagem , Interleucina-2/uso terapêutico , Leucaférese , Ativação Linfocitária , Transfusão de Linfócitos , Masculino , Pessoa de Meia-Idade , Neoplasias/sangue , Neoplasias/imunologia , Neoplasias/fisiopatologia , Óxido Nítrico Sintase , Transplante AutólogoRESUMO
Six renal transplant recipients with abnormal lymphoproliferative disorders were studied in an attempt to define their clinical features and the role of Epstein-Barr virus (EBV) in their pathogenesis. Patients were either teenage (three) or in the sixth decade (three). The younger patients presented an average of 3 months after transplantation with fever, sore throat, and lymphadenopathy; had been markedly immunosuppressed; frequently had preceding or concomitant cytomegalovirus infections; and two of three had a rapidly fatal course. The older patients presented an average of 5 years after transplantation while on maintenance immunosuppressive drugs; in two of three cases with an oropharyngeal tumor; and had a more indolent, but frequently fatal, clinical course. The most frequent sites of biopsy-proven involvement in these patients were lymph nodes (three), the oropharynx (three), liver (three), bone marrow (three), transplanted kidney (three), colon (two), and central nervous system (two). EBV-specific antibody titers including anti-viral capsid antigen IgG, anti-viral capsid antigen IgM, anti-early antigen, and anti-Epstein-Barr nuclear antigen were serially measured in all patients. Four patients demonstrated serological evidence of a primary (one) or reactivation (three) EBV infection. No patient had significant changes in anti-early antigen or anti-Epstein-Barr nuclear antigen titers. All three patients tested for oropharyngeal shedding of EBV were positive. A touch imprint of one tumor was stained for the presence of Epstein-Barr nuclear antigen, and a majority of cells were positive. EBV complementary RNA/DNA filter hybridization and/or viral DNA/DNA reassociation analysis performed on tumor biopsy specimens in five patients demonstrated multiple EBV genome equivalents per cell in all eight specimens tested. Clinical, pathological, serological, and molecular hybridization studies provide substantial evidence that EBV was the cause of these lymphoproliferative disorders occurring after renal transplantation. Impaired host defenses allow the EBV-transformed B-lymphocytes to escape normal control mechanisms. This impairment is invariable and influenced by many factors resulting in the observed spectrum of disease. Cytogenetic changes, however, may also be important.
Assuntos
Herpesvirus Humano 4 , Transplante de Rim , Transtornos Linfoproliferativos/etiologia , Adolescente , Adulto , Idoso , Animais , Anticorpos Antivirais/análise , Linfócitos B , Capsídeo/imunologia , Genes Virais , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/imunologia , Humanos , Imunoglobulina G/análise , Imunoglobulina M/análise , Fígado/microbiologia , Linfonodos/microbiologia , Transtornos Linfoproliferativos/imunologia , Transtornos Linfoproliferativos/patologia , Pessoa de Meia-Idade , Faringe/microbiologia , Infecções Tumorais por Vírus/imunologiaRESUMO
Although nitric oxide (NO) induces neuronal cell death under some conditions, it also can prevent apoptosis resulting from growth factor withdrawal. We investigated the molecular mechanism by which NO protects undifferentiated and differentiated PC12 cells from trophic factor deprivation-induced apoptosis. PC12 cells underwent apoptotic death in association with increased caspase-3-like activity, DNA fragmentation, poly(ADP-ribose) polymerase (PARP) cleavage, and cytochrome c release after 24 hr of serum withdrawal. The apoptosis of PC12 cells was inhibited by the addition of NO-generating donor S-nitroso-N-acetylpenicillamine (SNAP) (5-100 microM) and the specific caspase-3-like protease inhibitor Ac-Asp-Glu-Val-Asp-aldehyde (Ac-DEVD-cho) but not the YVADase (or caspase-1-like protease) inhibitor N-acetyl-Tyr-Val-Ala-Asp-aldehyde (Ac-YVAD-cho). SNAP and Ac-DEVD-cho prevented the increase in DEVDase (caspase-3-like protease) activity. The SNAP-mediated suppression of DEVDase activity was only minimally reversed by the incubation of cell lysate with dithiothreitol, indicating that NO did not S-nitrosylate caspase-3-like proteases in PC12 cells. Western blot analysis showed that NO inhibited the proteolytic activation of caspase-3. The cGMP analog 8-bromo-cGMP (8-Br-cGMP) blocked apoptotic cell death, caspase-3 activity and activation, and cytochrome c release. The soluble guanylyl cyclase inhibitor 1-H-oxodiazol-[1,2,4]-[4,3-a] quinoxaline-1-one (CODQ) significantly attenuated NO-mediated, but not 8-Br-cGMP-dependent, inhibition of apoptotic cell death, PARP cleavage, cytochrome c release, and DEVDase activity. Furthermore, the protein kinase G inhibitor KT5823 reversed both SNAP- and 8-Br-cGMP-mediated anti-apoptotic events. All these apoptotic phenomena were also suppressed by NO production through neuronal NO synthase gene transfer into PC12 cells. Furthermore, similar findings were observed in differentiated PC12 cells stimulated to undergo apoptosis by NO donors and NGF deprivation. These findings indicate that NO protects against PC12 cell death by inhibiting the activation of caspase proteases through cGMP production and activation of protein kinase G.
Assuntos
Apoptose/fisiologia , Inibidores de Caspase , GMP Cíclico/metabolismo , Óxido Nítrico/fisiologia , Animais , Caspase 3 , Diferenciação Celular/fisiologia , Meios de Cultura Livres de Soro , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Grupo dos Citocromos c/metabolismo , Ativação Enzimática , Técnicas de Transferência de Genes , Fatores de Crescimento Neural/deficiência , Células PC12 , Peptídeo Hidrolases/metabolismo , Ratos , Transdução de Sinais/fisiologiaRESUMO
The successful outcome of a pregnancy in a juvenile diabetic after renal transplantation is reported. It is proposed that class T be added to the classification of pregnancies complicated by diabetes mellitus. Pregnancy prevention should be considered until significant longevity can be demonstrated in diabetics receiving renal transplants.
Assuntos
Diabetes Mellitus Tipo 1 , Transplante de Rim , Gravidez em Diabéticas , Adulto , Cegueira , Nitrogênio da Ureia Sanguínea , Catarata , Creatinina/metabolismo , Parto Obstétrico , Diabetes Mellitus Tipo 1/classificação , Estriol/metabolismo , Feminino , Humanos , Rim/fisiopatologia , Taxa de Depuração Metabólica , Testes de Função Placentária , Pré-Eclâmpsia , Gravidez , Proteinúria/urina , Transplante HomólogoRESUMO
Kidneys of patients with severe diabetic nephropathy demonstrate marked linear immunofluorescent staining of extracellular membranes, including the tubular and glomerular basement membranes (TBM and GBM) and Bowman's capsule. Immunofluorescent studies were carried out on kidney tissue obtained from 12 diabetic and 17 nondiabetic patients from two to 12 years following renal transplantation. The frequency and intensity of SgG and albumin staining of these membranes were significantly greater in the diabetic than in the nondiabetic patients (P less than 0.0005). TBM, GBM, and Bowman's capsule staining did not occur in any of the seven kidneys studies at the time of their transplantation into diabetic recipients. Thus, the abnormalities leading to the deposition or trapping of proteins in renal extracellular membranes occur early after the placement of normal kidneys into the abnormal metabolic environment of the diabetic transplant recipient. The present study supports the concept that basement membrane alterations in diabetes are a consequence of the biochemical perturbations of diabetes rather than a separately inherited genetically linked disorder.
Assuntos
Albuminas/metabolismo , Nefropatias Diabéticas/imunologia , Imunoglobulina A/metabolismo , Nefropatias/imunologia , Glomérulos Renais/imunologia , Transplante de Rim , Túbulos Renais/imunologia , Membrana Basal/imunologia , Neuropatias Diabéticas/patologia , Feminino , Imunofluorescência , Humanos , Rim/metabolismo , Rim/patologiaRESUMO
Lipopolysaccharide binding protein (LBP) is a plasma protein that plays an important intermediary role in host-endotoxin (LPS) interactions. LBP binds with high affinity to the lipid A portion of LPS and then interacts with the monocytic differentiation antigen CD14 to markedly up-regulate TNF-alpha production by mononuclear phagocytes. In the presence of LBP, 100-fold less LPS is required to trigger this cytokine response. LBP has been implicated in the interaction of LPS with both CD14+ (monocytes, macrophages, neutrophils) and CD14-cells (endothelial and epithelial cells) to promote such varying responses as secretion of cytokines and nitric oxide (NO), expression of adhesion molecules, production of tissue factor, and activation of neutrophils. Non-CD 14-bearing cells, such as endothelial cells, can also respond to LPS through this pathway via the soluble form of CD14, an interaction that is similarly enhanced by LBP. Recently, it has been proposed that LBP cannot only potentiate host responses to LPS but can also facilitate the neutralization of LPS under certain conditions. LBP has been described as acting as a lipoprotein transfer protein facilitating the transfer of LPS both to the target receptor (CD14) and lipoprotein (HDL).
Assuntos
Proteínas de Fase Aguda/farmacologia , Proteínas de Transporte/farmacologia , Lipopolissacarídeos/farmacologia , Ativação de Macrófagos/efeitos dos fármacos , Glicoproteínas de Membrana , Ativação de Neutrófilo/efeitos dos fármacos , Animais , HumanosRESUMO
Macrophage nitric oxide (NO) synthesis is an integral component of the host defense system. We have previously found that NO and prostaglandins interact in a variety of ways. NO modulates Kupffer cell prostaglandin E2 (PGE2) production and we have recently described the inhibitory effects of PGE2 on NO synthesis in both Kupffer cells and hepatocytes. Activated macrophages produce a number of prostaglandins but studies regarding the capacity of prostaglandins to regulate macrophage NO synthesis have yielded conflicting results. We found that exogenous PGE2 decreased lipopolysaccharide (LPS)-induced NO synthesis in murine resident peritoneal macrophages and in the RAW 264.7 murine macrophage cell line. PGE2 also suppressed NO synthesis in response to interferon-gamma (IFN-gamma) alone and a combination of LPS + IFN-gamma. Inhibition of endogenous PGE2 synthesis with indomethacin or ibuprofen had no effect on NO synthesis. PGE2 added with the activating stimulus was most effective. PGE2 lost the capacity to block NO synthesis if added more than 180 min after LPS. PGE2 decreased inducible NO synthesis (iNOS) mRNA and immunoreactive iNOS protein, consistent with the hypothesis that exogenous PGE2 inhibits macrophage iNOS expression but that the inhibition depends on the time and concentration of prostaglandin exposure.