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1.
Scand J Gastroenterol ; 57(9): 1024-1029, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35450519

RESUMO

BACKGROUND: Esophageal adenocarcinoma (EAC) is the sixth leading cause of cancer-related death worldwide. It develops through Barrett's metaplasia - dysplasia sequence. However, the effectiveness of endoscopic surveillance is limited, since diagnosis of low-grade dysplasia (LGD) is known to be challenging for pathologists. Our aim was to compare the risk of Barrett's progression based on diagnoses of general and expert gastrointestinal (GI) pathologists in a population-based cohort. METHODS: A total of 60 patients with non-dysplastic metaplasia (BE) or LGD progressing to high grade dysplasia (HGD) or EAC during follow-up could be identified in the population. For comparison, series representing non-progressive BE (n = 56) and LGD cases (n = 54), matched for age, gender, and length of follow-up were collected. All available original HE stained slides (n = 292) were blindly re-evaluated by two experienced GI pathologists and patient groups of progressive non-progressive BE and LGD were formed according to revised diagnoses. RESULTS: Original diagnosis for each sample was changed in 25% of BE, 59% of LGD, and 33% of HGD diagnoses. Of the original LGD diagnoses, 53% were downgraded to BE or indefinite for dysplasia (ID). Of LGD diagnoses made by an expert GI pathologist, 61% were in the progressive LGD group, whereas only 42% of general pathologists' LGD diagnoses were in the progressive LGD group. CONCLUSION: Based on this retrospective case-control study, LGD is strongly over-diagnosed among general pathologists. LGD diagnosed by expert GI pathologists predicts progressive disease. Recommendation for consensus diagnosis by expert GI pathologists is justified also in the Finnish population-based setting.


Assuntos
Esôfago de Barrett , Neoplasias Esofágicas , Lesões Pré-Cancerosas , Adenocarcinoma , Esôfago de Barrett/patologia , Estudos de Casos e Controles , Progressão da Doença , Neoplasias Esofágicas/patologia , Finlândia , Humanos , Hiperplasia , Metaplasia , Patologistas , Lesões Pré-Cancerosas/patologia , Estudos Retrospectivos
2.
J Transl Med ; 11: 224, 2013 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-24060405

RESUMO

BACKGROUND: Antibodies binding to citrullinated proteins are a frequent finding in rheumatoid arthritis patients and may precede the onset of clinical symptoms several years. The antibodies are a predisposing factor for bone erosions but their origin is unknown. In this study we analyze in detail the levels of protein bound citrulline and homocitrulline in several tissue samples of a single erosive arthritic surgery patient. METHODS: Serum antibodies binding to CCP, MCV and citrulline- or homocitrulline-containing type I and II collagen carboxytelopeptides were measured. Tissue samples of a single RA patient, taken in two separate operations performed with two-year time span were hydrolyzed and analyzed for citrulline and homocitrulline content by HPLC. RESULTS: Protein-bound citrulline and homocitrulline were found in several joint tissues of a RA patient with ACPA-positive erosive disease. The amount of homocitrulline stayed relatively constant between the different tissues. The amount of citrulline in erosive tissue was 3-times higher than in non-erosive tissue in the first operation. In the samples of the second operation 3-4-times higher mean amounts of citrulline were found in two out of the six tissues investigated. CONCLUSIONS: Homocitrulline is present in rheumatoid nodule together with citrulline. There is more variation in the amount of citrulline than in the amount of homocitrulline between the tissues. The tissue sample containing the most citrulline was the most erosive.


Assuntos
Artrite Reumatoide/imunologia , Autoanticorpos/imunologia , Citrulina/análogos & derivados , Articulações do Pé/imunologia , Artrite Reumatoide/diagnóstico por imagem , Artrite Reumatoide/patologia , Artrite Reumatoide/cirurgia , Cromatografia Líquida de Alta Pressão , Citrulina/imunologia , Feminino , Articulações do Pé/diagnóstico por imagem , Articulações do Pé/patologia , Articulações do Pé/cirurgia , Humanos , Pessoa de Meia-Idade , Ligação Proteica , Radiografia
3.
Virchows Arch ; 481(3): 467-476, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35614270

RESUMO

Barrett's esophagus progresses to high-grade dysplasia or cancer along the well-established metaplasia-dysplasia-adenocarcinoma sequence. The aim of this study was to evaluate the value of p53, Ki67, and toll-like receptor 5 (TLR5) in prediction of malignant progression of Barrett's metaplasia and low-grade dysplasia. This was a retrospective matched case-control study based on Northern and Central Finland population. Patients diagnosed with esophageal high-grade dysplasia or adenocarcinoma were included. From these patients, all previous endoscopy samples were obtained along with original diagnostic HE-slides and clinical data. Age- and sex-matched patients with non-progressing Barrett's metaplasia and low-grade dysplasia confirmed with follow-up endoscopies were used as controls. Two gastrointestinal pathologist re-reviewed all original HE-slides, and newly made sections to confirm representative tissue material blinded from clinical data. p53, Ki67, and TLR5 were immunohistochemically stained. Final cohort included 45 patients with progressive Barrett's metaplasia (n = 21) or low-grade dysplasia (n = 24), and 92 patients with non-progressive Barrett's metaplasia (n = 52) or low-grade dysplasia (n = 40). In Barrett's metaplasia, aberrant p53 expression was observed in 6% of samples in progressors and 0% in non-progressors. In low-grade dysplasia, aberrant p53 was seen in 56% of samples in progressors and 17% in non-progressors (Odd's ratio 6.7, 95% CI 1.8-24.6). Ki67 or TLR5 showed no association with disease progression. In this matched case-control study, p53 expression associated with a high risk of malignant progression in Barrett's low-grade dysplasia. Routine staining of p53 is indicated in expert confirmed low-grade dysplasia.


Assuntos
Adenocarcinoma , Esôfago de Barrett , Neoplasias Esofágicas , Adenocarcinoma/patologia , Esôfago de Barrett/patologia , Estudos de Casos e Controles , Neoplasias Esofágicas/patologia , Humanos , Antígeno Ki-67/metabolismo , Metaplasia , Estudos Retrospectivos , Receptor 5 Toll-Like/metabolismo , Proteína Supressora de Tumor p53
4.
Cytotherapy ; 12(5): 593-604, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20513166

RESUMO

BACKGROUND AIMS: Congenital pseudarthrosis of the tibia (CPT) caused by neurofibromatosis type 1 (NF1) is a refractory disease occurring in childhood. We present two cases that had failed all earlier treatment attempts and, as a last treatment attempt, the patients were chosen to receive mesenchymal stromal cell (MSC) transplantation prior to amputation. METHODS: The MSC from bone marrow (BM) were harvested from the iliac crest and cultured in osteoinductive medium for 3 weeks. The cultured MSC were injected in solution into BM canals of the tibia and around the resection line or bone defect in a 3-dimensional collagen sponge scaffold. After the MSC transplantation, the patients were monitored during a 10-month follow-up period. In both cases, bone formation at the pseudarthrosis site was observed and two of three treated bone defects healed. For clinical reasons not related to cell transplantation, such as new infection and pseudarthrosis and severe shortening of the leg, both extremities were finally amputated and bone samples were analyzed to evaluate MSC therapy effect and safety. RESULTS: MSC transplantation normalized bone remodeling, promoted bone resorption and improved the overall structure of bone. The number of osteoclasts in the cortical bone was 2-fold higher compared with the monitored situation before MSC transfer. In addition, the mineral content of the bone improved after transplantation. We could see no sign of aberrant bone formation or malignant transformation. CONCLUSIONS: Our data suggest that MSC transplantation is a possibility for treatment of CPT caused by NF1 in less severe cases without adjunct defects.


Assuntos
Medula Óssea/patologia , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/metabolismo , Pseudoartrose/terapia , Tíbia/metabolismo , Remodelação Óssea , Calcificação Fisiológica , Células Cultivadas , Criança , Humanos , Masculino , Células-Tronco Mesenquimais/citologia , Neurofibromatose 1/genética , Neurofibromatose 1/fisiopatologia , Osteogênese , Pseudoartrose/congênito , Pseudoartrose/fisiopatologia , Células Estromais/citologia , Células Estromais/transplante , Tíbia/patologia , Tíbia/cirurgia , Alicerces Teciduais
5.
Arthritis Res Ther ; 18(1): 239, 2016 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-27765067

RESUMO

BACKGROUND: Seropositive rheumatoid arthritis (RA) is characterized by autoantibodies binding to citrullinated and homocitrullinated proteins. We wanted to study the expression patterns of these disease-associated protein forms and if the rheumatoid nodule and synovial tissue itself contain biologically active levels of citrullinating peptidyl arginine deiminases 2, 3 and 4 and homocitrullination-facilitating neutrophil enzyme myeloperoxidase. METHOD: Total of 195 synovial samples from metatarsal joints from five ACPA/RF-positive RA patients (n = 77), synovial samples from knees of eight seropositive RA (n = 60), seven seronegative RA (n = 33) and five osteoarthritis (n = 25) patients were analyzed for citrulline and homocitrulline contents using HPLC. The location of citrulline- and homocitrulline-containing proteins, PAD 2, 3, 4 and myeloperoxidase were shown by immunostaining. Myeloperoxidase and citrulline- or homocitrulline-containing proteins were stained on Western blot. RESULTS: Overall, necrosis was frequent in metatarsals of seropositive RA and absent in seronegative RA and osteoarthritis patients. In histological analysis, there was a significant local patterning and variation in the citrulline and homocitrulline content and it was highest in metatarsal synovial tissues of seropositive RA patients. We found peptidyl arginine deiminase 2, 3 and 4 in the lining and sublining layers of intact synovial tissue. Myeloperoxidase was found locally around necrotic areas. The tissues with necrosis contained the highest levels of citrulline and homocitrulline. CONCLUSIONS: Rheumatoid nodules and synovia contain significant amount of PAD2, 3 and 4 and myeloperoxidase enzymes. These enzymes could explain the levels of citrulline and homocitrulline in seropositive RA synovial and rheumatoid nodule tissues especially around necrotic tissue.


Assuntos
Artrite Reumatoide/imunologia , Artrite Reumatoide/metabolismo , Autoantígenos/imunologia , Autoantígenos/metabolismo , Idoso , Western Blotting , Cromatografia Líquida de Alta Pressão , Citrulina/análogos & derivados , Citrulina/imunologia , Citrulina/metabolismo , Feminino , Humanos , Hidrolases/metabolismo , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Peroxidase/metabolismo , Proteína-Arginina Desiminase do Tipo 2 , Desiminases de Arginina em Proteínas
6.
J Am Coll Cardiol ; 39(1): 96-101, 2002 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-11755293

RESUMO

OBJECTIVES: We sought to assess tenascin-C (TN-C) expression and its possible pathobiological impact in human aortic valve stenosis. BACKGROUND: Tenascin-C, a large extracellular matrix glycoprotein, has lately been increasingly connected to cardiovascular pathologies. As TN-C is a multifunctional protein implicated in cell proliferation, migration and differentiation, we investigated the pattern of its expression in diseased human aortic valves. METHODS: Fifty-five tricuspid, non-rheumatic stenotic aortic valves were collected from patients undergoing aortic valve replacement, and the controls consisted of four normal valves from individuals who had suffered traumatic death and one from a patient operated on because of a noncalcified purely regurgitant valve. A monoclonal mouse antibody to human TN-C (143DB7) was used as the primary antibody in immunostaining. To study the source of TN-C messenger RNA synthesis, some tissue samples were also examined using in situ hybridization. In order to identify smooth muscle cell differentiation, commercially available antibodies against alpha-smooth muscle actin were used, and immunophenotypic analysis of inflammatory cells was carried out by using the monoclonal mouse antibodies UCHL-1, L26 and PGM-1. RESULTS: In normal valves, TN-C expression was associated with the basement membrane beneath the endothelial cells, whereas stenotic valves showed no such expression but rather immunoreactivity in the deeper layers of the valves. This reactivity was associated with the characteristics typical of the stenosing process and the increased mechanical loading caused by hypertension. CONCLUSIONS: We hypothesize that the overexpression of TN-C in stenotic human aortic valves may emphasize that this disease is an active rather than a degenerative process.


Assuntos
Estenose da Valva Aórtica/metabolismo , Tenascina/metabolismo , Idoso , Idoso de 80 Anos ou mais , Progressão da Doença , Feminino , Humanos , Imuno-Histoquímica , Hibridização In Situ , Masculino , Pessoa de Meia-Idade , Regulação para Cima
7.
Eur J Cancer ; 41(17): 2645-54, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16239109

RESUMO

AIM OF THE STUDY: Previous work has indicated that quantification of inflammatory cell reaction is of prognostic value in colorectal cancer. We evaluated the prognostic significance of inflammatory cell reaction patterns in colorectal cancer and developed a grading method which could be used in the routine assessment of tumours. METHODS: The intensity of overall inflammatory cell reaction, numbers of neutrophilic and eosinophilic granulocytes, lymphoid cells and macrophages in both the central region and the invasive margin were estimated in 386 colorectal cancer patients. Prognostic significance was analysed by uni- and multivariate analysis. RESULTS: Our method for classification of inflammatory reaction was reliable. High-grade inflammation at the invasive margin in Dukes' stage A and B cancers (pT1-2N0 and pT3N0, respectively) was associated with better 5-year-survival (87.6%) than low-grade inflammation (47.0%). CONCLUSIONS: Inflammatory cell response at the invasive border is a relevant prognostic indicator and could be easily incorporated into the routine evaluation of histopathological specimens.


Assuntos
Colite/patologia , Neoplasias Colorretais/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/análise , Criança , Doença de Crohn/patologia , Intervalo Livre de Doença , Feminino , Humanos , Macrófagos/patologia , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Prognóstico
8.
APMIS ; 111(4): 451-7, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12780518

RESUMO

Even though the roles of different known or suggested prognostic factors in laryngeal cancer have been studied in detail, clinical stage at time of diagnosis and anatomic subsite of the tumour remain the only practical predictors of clinical outcome and offer the only guidelines in the planning of treatment. In this study, the relative roles of known demographic and clinical prognostic factors, in addition to four histopathological factors, were evaluated in a sample of 100 laryngeal carcinoma patients with multivariate analysis using the Cox regression model. In addition to advanced stage (stage III-IV) (relative hazard of death (HR) 8.9, p=0.01) and supraglottic disease (HR 5.6, p=0.02), high apoptotic index (HR 11.1, p=0.05) was significantly associated with poor survival. Cell proliferation, p53 and angiogenesis did not significantly affect the prognosis. In the future, high degree of apoptosis could be used to identify patients with poor prognosis in laryngeal cancer.


Assuntos
Apoptose/fisiologia , Carcinoma de Células Escamosas/irrigação sanguínea , Carcinoma de Células Escamosas/patologia , Antígeno Ki-67/metabolismo , Neoplasias Laríngeas/irrigação sanguínea , Neoplasias Laríngeas/patologia , Neovascularização Patológica/patologia , Proteína Supressora de Tumor p53/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/metabolismo , Feminino , Humanos , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Neoplasias Laríngeas/metabolismo , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Modelos de Riscos Proporcionais , Fumar , Proteína Supressora de Tumor p53/biossíntese , Proteína Supressora de Tumor p53/genética
9.
Anticancer Res ; 24(6): 4247-53, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15736480

RESUMO

BACKGROUND: Matrix metalloproteinases (MMPs) are involved with tumour invasion and metastasis. Controversial data exists concerning the prognostic value of MMP-9 in breast carcinoma. We examined, here, whether the MMP-9 immunoreactive protein would correlate with--the prognosis in breast carcinoma treated with hormonal adjuvant therapy. MATERIALS AND METHODS: The MMP-9 status was determined immunohistochemically from primary tumour specimens in 168 postmenopausal breast cancer patients with a locally advanced (N+) disease treated with antiestrogen for three years after the primary therapy. RESULTS: A positive immunostaining for MMP-9 was found in 61.3% of 168 primary tumours without any significant correlation to clinical stage, histology or hormone receptor status. MMP-9 immunoreactivity did not correlate with the survival when the entire study population was included in the analysis. There was, however, a compromised disease-free survival in a subgroup of patients presenting with an estrogen receptor-negative and MMP-9-positive tumour. The 5-year disease-free survival was only 37% in those patients, when it was 63% in the patients with a tumour negative for both estrogen receptor and MMP-9. CONCLUSION: We suggest that the prognostic value of MMP-9 immunoreactivity in the primary tumour is not generally strong in breast carcinoma, but it might correlate with the clinical benefit of an antiestrogen therapy, since MMP-9 positivity seemed to correlate with early recurrence in patients with an estrogen receptor-negative primary tumour.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/enzimologia , Moduladores de Receptor Estrogênico/uso terapêutico , Metaloproteinase 9 da Matriz/metabolismo , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos Hormonais/uso terapêutico , Neoplasias da Mama/patologia , Carcinoma Ductal/tratamento farmacológico , Carcinoma Ductal/enzimologia , Carcinoma Ductal/patologia , Quimioterapia Adjuvante , Intervalo Livre de Doença , Feminino , Humanos , Imuno-Histoquímica , Metástase Linfática , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/enzimologia , Recidiva Local de Neoplasia/patologia , Estadiamento de Neoplasias , Receptores de Estrogênio/metabolismo , Tamoxifeno/uso terapêutico , Toremifeno/uso terapêutico
10.
Cancer Epidemiol Biomarkers Prev ; 19(2): 381-7, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20142239

RESUMO

BACKGROUND: We assessed the performance and validity of cytology in the Finnish screening program by considering high-grade neoplasia and cervical cancer (CIN3+) rates as detected in the program and by reevaluating cases observed after a negative screening test. METHODS: This retrospective study included 915 screen-detected CIN3+ cases and 421 cases observed after a negative screen. Randomized and blinded reevaluation of potential false-negative screening tests covered 345 archival case smears from women without a referral to colposcopy, as well as 689 control smears for estimating performance and validity measures. RESULTS: The false-negative rate at the cutoff of low-grade squamous intraepithelial lesion or worse was 35% (95% confidence interval, 30-40%). In the subpopulation with original screening result of Pap I, the false-negative rate was 23% (18-28%). Sensitivity of screening laboratory rereading for detecting low-grade lesions or worse as atypical was 75% (67-82%) and specificity 93% (91-94%). Reproducibility of specific cytologic diagnoses was only fair. False negatives constituted 11% of all CIN3+ diagnoses in the screened population; those false negatives with an original Pap I screening result constituted 5%. CONCLUSIONS: Although screen failures in the form of diagnostic false negatives occur within the Finnish screening program, their effect on cancer incidence is fairly small and cannot be readily decreased without sacrificing the high specificity of screening or without high incremental costs. Feedback for the screening laboratories is needed, however, to improve the reproducibility of cytologic diagnoses to optimize the burden of intensified follow-up and treatment of precancerous lesions.


Assuntos
Carcinoma in Situ/diagnóstico , Carcinoma in Situ/epidemiologia , Neoplasias do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/epidemiologia , Adulto , Reações Falso-Negativas , Feminino , Finlândia , Humanos , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Estudos Retrospectivos , Sensibilidade e Especificidade , Esfregaço Vaginal
11.
Histol Histopathol ; 24(10): 1207-11, 2009 10.
Artigo em Inglês | MEDLINE | ID: mdl-19688689

RESUMO

UNLABELLED: Tendon tissue degeneration and changes in collagen composition play a role in spontaneous rupture of the human Achilles tendon. Tenascin-C has been shown to be present in the tissue pathology and changes in tissue loading. We made an immunohistological study of the expression of tenascin-C and type I and III collagens in ruptured human Achilles tendons. METHODS: Three tissue samples in ten individuals, one from the Achilles tendon rupture and two control samples from four and sixteen centimeters proximal in same tendon were collected at surgery. The specimen were fixed and labelled with specific antibodies to type I and III procollagens (PICP, PINP and PIIINP), mature type III collagen (IIINTP) and tenascin-C. The amount of reacting tissue was evaluated visually and graded on a semiquantitative scale. RESULTS: No difference in the expression of tenascin-C was found between the sites. Instead, mature type III collagen content (p=0.008) and type III collagen synthesis (p=0.016) were significantly increased at the rupture site relative to the control site 2. The amount of newly synthesized type I collagen (PINP, PICP) was relatively high at all sites, as expected. CONCLUSION: The expression of type III collagen is increased at the rupture site in the human Achilles tendon, but that of tenascin-C remains unchanged. This finding supports a tissue composition alteration background for Achilles tendon rupture, while the role of mechanical loading at the rupture site remains controversial.


Assuntos
Tendão do Calcâneo/lesões , Tendão do Calcâneo/metabolismo , Colágeno Tipo III/metabolismo , Colágeno Tipo I/metabolismo , Tenascina/metabolismo , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ruptura/metabolismo , Ruptura/patologia
12.
J Invest Dermatol ; 129(6): 1379-87, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19052563

RESUMO

Electron probe microanalysis was used to analyze elemental content of human epidermis. The results revealed that the calcium content of the basal keratinocyte layer was higher than that of the lowest spinous cell layer in normal epidermis. This was surprising, as it is generally accepted that the calcium level increases with cellular differentiation from the proliferative basal layer to the stratum corneum. Hailey-Hailey disease (HHD) and Darier disease (DD) are caused by mutations in Ca(2+)-ATPases with the end result of desmosomal disruption and suprabasal acantholysis. The results demonstrated three major aberrations in HHD and DD lesions. First, in HHD and DD lesions the calcium content in the basal layer was lower than in the normal skin. Second, adenosine triphosphate (ATP) receptor P2Y2 was not localized to plasma membrane in acantholytic cells, whereas P2X7 appeared in the plasma membrane, potentially mediating apoptosis. Third, transition of keratin 14 to keratin 10 was abnormal as demonstrated by the presence of keratinocytes expressing both cytokeratins, which are usually exclusive in normal epidermis. Our results provide to our knowledge previously unreported elements for understanding how the disturbed calcium gradient is linked to the alterations in ATP receptors and keratin expression, leading to the clinical findings in HHD and DD.


Assuntos
Cálcio/metabolismo , Doença de Darier/metabolismo , Epiderme/metabolismo , Pênfigo Familiar Benigno/metabolismo , Receptores Purinérgicos P2/metabolismo , Adulto , Idoso , ATPases Transportadoras de Cálcio/metabolismo , Membrana Celular/metabolismo , Humanos , Queratina-10/metabolismo , Queratina-14/metabolismo , Pessoa de Meia-Idade , Receptores Purinérgicos P2Y2 , Pele/patologia
13.
Mol Cell Biochem ; 229(1-2): 63-72, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11936848

RESUMO

The present study was prompted by findings in our laboratory showing that serum effectively inhibits scavenger receptor (SR)-mediated endocytosis in hepatic sinusoidal endothelial cells (SEC). Experiments with SEC in vitro showed that the presence of 20% human serum inhibited endocytosis of SR ligands, 125I-formaldehyde treated bovine serum albumin (FSA) and 125I-nidogen, by 30 and 50%, respectively, whereas pre-heated foetal bovine serum (10%) inhibited endocytosis of 125I-FSA by as much as 56%. Human, bovine and rat serum had similar inhibitory effect on endocytosis in SEC. Fractionation of foetal bovine and human serum on anion exchange chromatography demonstrated that the inhibitory principle co-purified with macromolecules of high negative charge. The serum fraction that most effectively inhibited SR-mediated endocytosis of 125I-FSA did not affect mannose receptor-mediated endocytosis of 125I-mannan to the same extent. Trap-labelled negatively charged serum fraction administered intravenously to rats was eliminated almost exclusively by liver, with a blood decay of 50% over the first 3 min after injection. Isolation of liver cells showed that the populations of Kupffer cells and SEC contained 39 and 61% of liver radioactivity 30 min after injection of trap-labelled negatively charged fractions prepared from pre-heated ('complement inactivated') foetal bovine sera. These findings suggest that the process of serum formation from native blood generates appreciable amounts of macromolecules that compete specifically with the SR for endocytosis in SEC. The inhibitory power of pre-heated serum is particularly great. For this reason pre-heated serum should be used with caution in studies of SR in SEC.


Assuntos
Sangue , Endocitose/fisiologia , Fígado/metabolismo , Proteínas de Membrana , Receptores Imunológicos/metabolismo , Receptores de Lipoproteínas , Animais , Bovinos , Cromatografia por Troca Iônica , Eletroforese em Gel de Poliacrilamida , Endotélio/metabolismo , Formaldeído/metabolismo , Humanos , Radioisótopos do Iodo/metabolismo , Ligantes , Masculino , Mananas/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores Depuradores , Receptores Depuradores Classe B , Soroalbumina Bovina/metabolismo
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