Using ethnography to investigate life scientists'' information needs

Although several liver diseases of childhood, particularly biliary atresia (BA) and cystic fibrosis (CF) liver disease (CFLD) are characterized by hepatic fibrosis, the pathogenesis of this process is incompletely understood. The cytokine transforming growth factor-beta1 (TGF-beta1) has been implicated in hepatic fibrosis in experimental animals, in which both the hepatic expression and plasma concentration of this cytokine are increased. The objective of our study was to determine whether there are similar alterations of TGF-beta1 in patients with hepatic fibrosis secondary to either BA and/or CFLD. The study design was as follows. In study 1, plasma TGF-beta1 was assessed by ELISA in 9 children with BA undergoing liver transplantation, 11 patients with CFLD, and appropriate control subjects. In study 2, hepatic expression of TGF-beta1 protein (assessed immunohistochemically) and hepatic fibrosis were scored semiquantitatively, on a 1-3 scale, by blinded investigators, in archival liver biopsy specimens from 10 children with BA, 10 with CFLD, and from 10 older children with normal hepatic histology, as well as in 4 patients with liver diseases of various etiologies. Simultaneous plasma and liver TGF-beta1 studies were performed in 8 patients with liver disease. Results were as follows. Plasma TGF-beta1 values were inversely correlated with age in healthy subjects (r=-0.54, p < 0.0001). The plasma TGF-beta1 protein of children with BA was decreased (13+/-2 ng/mL) compared with values for healthy children (42+/-6 ng/mL, n=10, p < 0.005). Similarly, the plasma TGF-beta1 concentration in patients with CFLD was also decreased compared with values for children with CF and normal serum liver profiles (n=14) (2+/-1 ng/mL versus 12+/-1, p < 0.05). However, the plasma TGF-beta1 concentration was increased in two patients with other types of liver disease. The hepatic expression of TGF-beta1 was increased in the presence of hepatic fibrosis in all types of liver diseases studied. Forty-six percent of patients had both marked hepatic fibrosis and marked TGF-beta1 labeling; 86% of samples without fibrosis showed no TGF-beta1 labeling, p=0.007. In conclusion, these studies have established the association of hepatic TGF-beta1 protein and hepatic fibrosis in several common liver diseases of childhood. Our data also suggest that, in children, plasma TGF-beta1 does not appear to be a useful marker of hepatic expression of this cytokine.     

Serum hyaluronate predicts response to interferon-alpha therapy in patients with chronic hepatitis C

BACKGROUND/AIMS: The response to interferon therapy for chronic hepatitis is known to decrease with progression of the hepatic fibrosis. On the other hand, serum hyaluronate reflects hepatic sinusoidal capillarization or liver cirrhosis, and also serum type IV collagen, which is one of the main components of the basement membrane, rises with the progression of hepatic fibrosis. In this study, the relationship between the degree of hepatic fibrosis and the response to interferon-alpha was determined retrospectively in patients with chronic hepatitis C. In addition, whether the measurement of serum hyaluronate and type IV collagen before interferon-alpha therapy was useful for predicting the response to interferon-alpha therapy in chronic hepatitis C was determined. MATERIALS AND METHODS: Thirty-seven patients with elevated serum ALT levels for at least 6 months and histologically determined chronic hepatitis were studied. All patients were positive for anti-HCV and negative for hepatitis B surface antigen. Twenty-eight healthy adults with normal blood biochemical data, who were negative for hepatitis B antigen and HCV antibody tests, had limited alcohol intake were used as controls. The test group was given IFN-alpha by intramuscular injection for 14 days, and then were treated 3 times per week for 24 weeks. RESULTS: The extent of hepatic fibrosis, particularly, perisinusoidal fibrosis (P < 0.01) was significantly greater in nonresponders than in responders. The mean serum hyaluronate and type IV collagen levels were more elevated in nonresponders than in responders, especially, the serum hyaluronate level showed a significant difference (P < 0.01). Most of the patients having a serum hyaluronate level of more than 100 ng/ml were nonresponders who had chronic active hepatitis with bridging necrosis on liver biopsy. Serum hyaluronate and type IV collagen levels showed significant positive correlation with degree of the portal fibrosis (P < 0.01), perisinusoidal fibrosis (P < 0.001) and focal necrosis (P < 0.01) in histological findings of liver biopsy specimens. CONCLUSION: These results suggest that serum hyaluronate and type IV collagen levels reflect the extent of the hepatic fibrosis in chronic hepatitis C and also that serum hyaluronate level predicts the response to interferon-alpha therapy in patients with chronic hepatitis C.     

The role of gap junctional intercellular communication (GJIC) disorders in experimental and human carcinogenesis

BACKGROUND: To evaluate the effect of plasminogen activator inhibitor type 1 (PAI-1) levels on the clearance of total tissue plasminogen activator (TPA) antigen, we studied the clearance of active TPA and TPA/PAI-1 complex in subjects with low (181+/-109 pmol/L; n=7) and high (1166+/-322 pmol/L; n=4) baseline active PAI-1. METHODS AND RESULTS: A 5-microg/kg bolus of TPA was infused over a 15-second period followed by measurement of TPA activity, TPA antigen, TPA/PAI-1, TPA/C1 inhibitor, PAI-1 activity, and PAI-1 antigen over a 4-hour period. alpha-Phase clearance of total TPA antigen was faster in subjects with low PAI-1 (t(1/2) of 3.5+/-0.7 minutes) versus high PAI-1 (t(1/2) of 5.3+/-0.9 minutes) (P=.006). Clearance of all factors was best fit by a two-compartment pharmacokinetic model based on a computer-simulated human circulatory system. The average hepatic clearance fraction in the two-compartment model was greater for active TPA (89+/-10%, t(1/2) of 2.4+/-0.3 minutes) than for TPA/PAI-1 complex (48+/-17%, t(1/2) of 5.0+/-1.8 minutes) (P=.0006). CONCLUSIONS: Plasma clearance of active TPA was faster than clearance of TPA/PAI-1 complex. High levels of active PAI-1 converted more TPA into TPA/PAI-1 complex, effectively slowing the clearance of total TPA antigen and explaining in part why high levels of PAI-1 activity are associated with increases in total TPA antigen.     

Pharmacokinetics of terbinafine and five known metabolites in children, after oral administration

BACKGROUND: Deferiprone is an orally active iron-chelating agent that is being evaluated as a treatment for iron overload in thalassemia major. Studies in an animal model showed that prolonged treatment is associated with a decline in the effectiveness of deferiprone and exacerbation of hepatic fibrosis. METHODS: Hepatic iron stores were determined yearly by chemical analysis of liver-biopsy specimens, magnetic susceptometry, or both. Three hepatopathologists who were unaware of the patients' clinical status, the time at which the specimens were obtained, and the iron content of the specimens examined 72 biopsy specimens from 19 patients treated with deferiprone for more than one year. For comparison, 48 liver-biopsy specimens obtained from 20 patients treated with parenteral deferoxamine for more than one year were similarly reviewed. RESULTS: Of the 19 patients treated with deferiprone, 18 had received the drug continuously for a mean (+/-SE) of 4.6+/-0.3 years. At the final analysis, 7 of the 18 had hepatic iron concentrations of at least 80 micromol per gram of liver, wet weight (the value above which there is an increased risk of cardiac disease and early death in patients with thalassemia major). Of 19 patients in whom multiple biopsies were performed over a period of more than one year, 14 could be evaluated for progression of hepatic fibrosis; of the 20 deferoxamine-treated patients, 12 could be evaluated for progression. Five deferiprone-treated patients had progression of fibrosis, as compared with none of those given deferoxamine (P=0.04). By the life-table method, we estimated that the median time to progression of fibrosis was 3.2 years in deferiprone-treated patients. After adjustment for the initial hepatic iron concentration, the estimated odds of progression of fibrosis increased by a factor of 5.8 (95 percent confidence interval, 1.1 to 29.6) with each additional year of deferiprone treatment. CONCLUSIONS: Deferiprone does not adequately control body iron burden in patients with thalassemia and may worsen hepatic fibrosis.     

Postoperative plasma concentrations of procalcitonin after different types of surgery

Transforming growth factor (TGF)-beta 1 is an important cytokine involved in the pathobiology of tissue fibrosis through its stimulation of the production of, and inhibition of the degradation of, extracellular matrix proteins. We examined the clinical usefulness of plasma TGF-beta 1 concentration as a marker of fibrogenesis in patients with chronic viral hepatitis. Thirty-five patients, 11 with minimal chronic hepatitis, 14 with mild chronic hepatitis and 10 with moderate chronic hepatitis and 20 healthy subjects were studied. Transforming growth factor-beta 1 concentrations in platelet-poor plasma were measured with a TGF-beta 1 enzyme-linked immunosorbent assay system kit after acid-ethanol extraction. Plasma TGF-beta 1 levels were significantly elevated in patients with mild and moderate chronic hepatitis, but not in those with minimal chronic hepatitis, compared with the levels in the controls. Plasma TGF-beta 1 levels were increased in parallel with the histological degree of necroinflammation and of liver fibrosis. Plasma TGF-beta 1 levels were positively correlated with blood levels of procollagen type III N-peptide, and 7S fragment and central triple-helix of type IV collagen. These results suggest that plasma TGF-beta 1 level is a useful marker in assessing the situation of liver active fibrogenesis in patients with chronic viral hepatitis.     

Plasma levels of fibronectin in patients with chronic viral and alcoholic liver disease

BACKGROUND/AIMS: Plasma fibronectin levels are reportedly decreased in patients with cirrhosis, while increases are associated with acute and chronic hepatitis. We studied 101 patients with chronic liver disease to determine the relationship between disease etiology and plasma fibronectin levels. METHODOLOGY: Plasma fibronectin levels and standard liver function parameters were measured in all patients and 11 healthy controls. Antipyrine metabolism was also evaluated in 39 patients. Results were analyzed according to etiology (HBV, HCV, alcohol abuse) and histological findings (chronic active hepatitis (CAH) with/without fibrosis, steatosis, cirrhosis). RESULTS: The fibronectin levels were similar in patients with HBV, HCV and alcohol-related disease. Analysis of the groups based on histological features showed that fibronectin levels in cirrhotics (mean 270.69 microg/ml) were significantly lower than those of the control (mean 372.00 microg/ml) and other patient groups (steatosis: 470.37 microg/ml; CAH: 417.93 microg/ml; CAH and fibrosis: 426.72 microg/ml). Plasma fibronectin displayed a positive correlation with antipyrine metabolism and parameters of hepatic synthesis. CONCLUSIONS: Plasma fibronectin appears to be an index of hepatic parenchymal function but shows no relation to the etiology of the liver disease.     

Initiation of a fibrinolytic system in hepatic resection: the roles of tissue-type plasminogen activator and plasminogen activator inhibitor-1

The factors related to the initiation of fibrinolysis, especially with regard to the tissue-type plasminogen activator (tPA) and the plasminogen activator inhibitor-1 (PAI-1), were investigated in 15 patients who underwent hepatic resection, and the findings were compared between those with normal livers and those with diseased livers. It was found that tPA increased before hepatic division, whereas PAI-1 increased after hepatic division and reached a peak immediately following the operation. Plasminogen decreased during hepatectomy, reaching its lowest point on postoperative day 1, and increasing later. Decreased levels of both plasminogen and the alpha 2-plasmin inhibitor were considered to be partly due to plasmin formation in the blood. Patients with a diseased liver tended to have higher intraoperative values of euglobulin lysis activity and higher postoperative values of plasminogen activator, but significantly lower postoperative values of alpha 2-plasmin inhibitor than those with a normal liver. The results of this study suggest that activation of the fibrinolytic system occurs both during hepatectomy and in the early postoperative period, and that patients with a diseased liver are prone to develop hyperfibrinolysis during hepatectomy. Moreover, the increased levels of both tPA and PAI-1 can serve as one of the most sensitive markers for the vital reaction against surgical stress.     

Blood flow and leukocyte adhesiveness are reduced in the microcirculation of a peritoneal disseminated colon carcinoma

BACKGROUND/AIMS: Transforming growth factor-beta1 (TGF-beta1) is considered the most important mediator of hepatic fibrogenesis. At the same time, TGF-beta1 is an immunosuppressive cytokine. Development of fibrosis, often rapid, is a characteristic of autoimmune hepatitis, as is spontaneous systemic immunosuppression. The aim of our study was therefore to define the role of TGF-beta1 in autoimmune hepatitis. METHODS/RESULTS: Using the MV 1Lu bioassay, we found markedly elevated serum levels of TGF-beta1 (median 109 ng/ml) in active autoimmune hepatitis, which normalised when patients reached biochemical remission following immunosuppressive therapy (median 34 ng/ml; p=0.0001 compared to active disease). With a newly established ELISPOT-assay for TGF-beta1-producing cells, we could exclude an increase in TGF-beta1-producing peripheral blood cells as a source of the elevated TGF-beta1. However, by in situ hybridisation and immunohistochemistry, we found strong TGF-beta1 expression in the inflamed liver. In addition to non-parenchymal and infiltrating cells, many hepatocytes showed strong staining for TGF-beta1. TGF-beta1 expression in the liver normalised in remission, yet was still somewhat increased in patients with biochemical remission but remaining histological disease activity. CONCLUSIONS: These results suggest that TGF-beta1 is an important mediator in active autoimmune hepatitis. They support the theory that immunosuppressive therapy needs to be guided by histology, as prevention of the development of cirrhosis presumably requires near complete suppression of TGF-beta1 in the liver; this is only found when there is no longer any histological evidence of inflammation.     

Enhanced urokinase plasminogen activation in chronic pancreatitis suggests a role in its pathogenesis

BACKGROUND & AIMS: Urokinase plasminogen activator (uPA) regulates plasmin generation from plasminogen. The aim of this study was to analyze the role of the plasminogen activator/plasmin system in chronic pancreatitis (CP). METHODS: Using Northern blot analysis, in situ hybridization, and immunohistochemistry, the expression of uPA, its receptor (uPAR), plasminogen activator inhibitor 1 (PAI-1), and transforming growth factor beta 1 (TGF-beta 1) was studied in 14 patients undergoing pancreatic resection for CP. Normal control pancreatic tissue was obtained through an organ donor program. RESULTS: Eight of 14 CP samples showed concomitant increased expression (P < 0.001) of uPA (5.2-fold), uPAR (5.9-fold), and TGF-beta 1 (8.8-fold) messenger RNA (mRNA) compared with normal controls. PAI-1 mRNA expression was increased (6.5-fold; P < 0.001) in all CP samples. By in situ hybridization, moderate to strong mRNA staining of all four factors was present in acinar cells, some ductal cells, and areas with ductal metaplasia in CP samples. A similar staining pattern was found by immunohistochemistry. Intense mRNA and immunostaining for all of these factors in CP samples was associated with a higher degree of pancreatic damage. CONCLUSIONS: uPA and its receptor may contribute to the lytic damage observed in CP by plasmin generation. Similarly, increased amounts of plasmin may activate latent TGF-beta, thereby leading to the accumulation of fibrotic tissue.     

Urethrolysis after surgical cure of stress urinary incontinence using colpopexy: surgical technics

Vitronectin (VN) is an obligatory cofactor for the inhibition of thrombin by plasminogen activator inhibitor 1 (PAI-1). It accelerates the rate of association between thrombin and PAI-1 more than two orders of magnitude. In contrast, VN does not accelerate the association between tissue-type plasminogen activator (t-PA) and PAI-1. Previously, we reported that the anti-PAI-1 monoclonal antibody (MoAb) CLB-2C8 binds to a short stretch of amino acids of PAI-1, located between residues 128 and 145, and prevents PAI-1 binding to VN. Furthermore, MoAb CLB-2C8 fully blocks the inhibitory activity of PAI-1 towards t-PA, emphasizing the importance of this area for the interaction with t-PA. Here, we show that this area is also required for the interaction between thrombin and PAI-1, since MoAb CLB-2C8 fully prevents inhibition of thrombin by PAI-1. In spite of similar structural requirements for the interaction between t-PA, PAI-1 and VN and between thrombin, PAI-1 and VN, the intermediate reaction products are clearly distinct. By employing surface plasmon resonance (SPR), using the BIAcore equipment, and by immunoprecipitation we demonstrate that, in the presence of VN, t-PA and PAI-1 form exclusively equimolar binary t-PA/PAI-1 complexes. Thrombin, PAI-1 and VN generate equimolar, binary thrombin/PAI-1 complexes and in addition equimolar, ternary complexes and multimers.     

High levels of transforming growth factor beta 1 in patients with colorectal cancer: association with disease progression

BACKGROUND & AIMS: Contribution of transforming growth factor beta 1 (TGF-beta 1) to tumor progression has been suggested. However, little is known about the role of TGF-beta 1 in colorectal cancer. Plasma TGF-beta 1 levels and its expression were analyzed in patients with colorectal cancer. METHODS: Plasma TGF-beta 1 levels were measured in 22 patients with colorectal cancer using a TGF-beta 1 enzyme-linked immunosorbent assay. Expression of TGF-beta 1 messenger RNA and immunohistochemical distribution of the protein in colorectal cancer tissues were examined. RESULTS: Plasma TGF-beta 1 levels in patients with colorectal cancer (14.8 +/- 8.4 ng/mL) were significantly higher than in normal controls (1.9 +/- 1.4; n = 22) (P < 0.001). After curative surgical resection, plasma TGF-beta 1 levels decreased in examined patients from 11.9 +/- 6.7 to 3.8 +/- 1.2 ng/mL (P < 0.01). TGF-beta 1 messenger RNA was about 2 1/2 times more abundant in colorectal cancer tissues than in control (P < 0.01). TGF-beta 1 was detected in the cytoplasm of colorectal cancer cells immunohistochemically. Both TGF-beta 1 messenger RNA expression in colorectal adenocarcinoma tissues and its plasma levels were associated with tumor stage of Dukes' classification (P < 0.05). CONCLUSIONS: These results suggest that plasma TGF-beta 1 levels may reflect overexpression of the gene in colon cancer tissues and are associated with disease progression.     

Assembly of an active enzyme by the linkage of two protein modules

BACKGROUND & AIMS: Oxidative stress mediates activation and stimulates collagen production of cultured hepatic stellate (Ito) cells. The aim of this study was to assess whether oxidative stress contributes to hepatic fibrogenesis in chronic hepatitis C. METHODS: In liver biopsy specimens of patients with chronic hepatitis C, the following fibrogenesis cascade was analyzed: (1) oxidative stress, determined by the presence of malondialdehyde protein adducts; (2) activation of stellate cells as indicated by their expression of alpha-smooth muscle actin; (3) stimulation of c-myb expression in stellate cells, a critical step in the activation of these cells; and (4) induction of collagen gene expression as detected by in situ hybridization. RESULTS: Treatment with d-alpha-tocopherol (1200 IU/day for 8 weeks) in 6 of these patients, who were refractory to interferon therapy, prevented the fibrogenesis cascade observed before antioxidant treatment. In addition, d-alpha-tocopherol treatment significantly decreased the carbonyl modifications of plasma proteins, a sensitive index of oxidative stress. However, 8 weeks of d-alpha-tocopherol treatment did not significantly affect serum alanine aminotransferase levels, hepatitis C virus titers, or histological degree of hepatocellular inflammation or fibrosis. CONCLUSIONS: These data suggest that enhanced oxidative stress initiates a fibrogenesis cascade in the liver of patients with chronic hepatitis C.     

Prognostic significance of febrile episodes in lung cancer patients receiving chemotherapy

AIM: To evaluate the prevalence of iron overload in chronic hepatitis C and its relationship with liver histology. PATIENTS AND METHODS: Serum iron, unsaturated iron binding capacity and ferritin levels were determined in 204 consecutive anti-hepatitis C virus positive subjects, whereas hepatic iron concentration, hepatic histological grading and staging, hepatitis C virus genotypes were further assessed in a subgroup of 50 patients who underwent liver biopsy for chronic hepatitis. RESULTS: An increase in the serum markers of iron metabolism was more frequently found in subjects with aminotransferase activities above the normal range, whereas hepatic iron overload, established by direct hepatic iron determination, was found only in 9/50 (18%) patients with chronic hepatitis C. No serum iron marker could reliably predict hepatic iron stores. Patients with mild iron overload usually showed active hepatitis and fibrosis, whereas iron overload was not present in patients without fibrosis or with very mild fibrosis. Two out of nine patients with iron overload were shown to be beta thalassaemia heterozygous, and two were heterozygous carriers of a putative haemochromatosis gene mutation (His63Asp). CONCLUSIONS: Many anti-hepatitis C virus positive patients with elevated aminotransferase activities have serum ferritin levels above the normal range, but only a minority of patients with chronic hepatitis C have a mild iron overload. In chronic hepatitis C, a relationship does exist between hepatic iron content and liver fibrosis.     

Immunohistochemical characterization of the plasminogen activator system in psoriatic epidermis

The relative topographical distribution of urokinase-type plasminogen activator (uPA), tissue-type PA (tPA), PA-inhibitor-1 (PAI-1), PA-inhibitor-2 (PAI-2), plasmin(ogen), alpha 2-antiplasmin, and alpha 2-macroglobulin was studied in lesional epidermis of psoriasis vulgaris, and in normal epidermis, by immunohistochemistry. In psoriatic epidermis, tPA predominated, although uPA was found in some biopsies. PAs were not detected in normal epidermis. PAI-1 was not detected in normal epidermis and was only present in a proportion of biopsies of psoriatic lesions. PAI-2 was found in normal and psoriatic epidermis. Plasmin(ogen) was confined to the basal cell layer of normal epidermis, whereas in lesional psoriatic skin it was scattered throughout the epidermis. Alpha 2-antiplasmin and alpha 2-macroglobulin were not found in the epidermis of normal skin. In psoriatic epidermis alpha 2-antiplasmin was confined to the subcorneal layer, whereas staining for alpha 2-macroglobulin was found only in a proportion of biopsies, in the upper epidermis. Our immunohistological findings indicate that colocalization of tPA and its substrate plasminogen may allow efficient generation of plasmin, and that the focal absence of plasmin inhibitors may then favour the persistence of plasmin activity.     

Dissociation between anxiolytic and hypomnestic effects for combined extracts of zingiber officinale and ginkgo biloba, as opposed to diazepam

Extrahepatic biliary atresia is a severe neonatal liver disease resulting from a sclerosing cholangiopathy of unknown etiology. Although biliary obstruction may be surgically corrected by a "Kasai" hepatoportoenterostomy, most patients still develop progressive hepatic fibrosis, although the source of increased collagen deposition is unclear. This study examined the role of hepatic stellate cells (HSCs) and assessed the source of transforming growth factor-beta (TGF-beta) production in hepatic fibrogenesis in patients with biliary atresia. Liver biopsies from 18 biliary atresia patients (including 5 pre- and post-Kasai) were subjected to immunohistochemistry for alpha-smooth muscle actin and in situ hybridization for either procollagen alpha1 (I) mRNA or TGF-beta1 mRNA. Sections were also subjected to immunohistochemistry for active TGF-beta1 protein. The role of Kupffer cells in TGF-beta1 production was assessed by immunohistochemistry for CD68. Procollagen alpha1 (I) mRNA was colocalized to alpha-smooth muscle actin-positive HSCs within the region of increased collagen protein deposition in fibrotic septa and surrounding hyperplastic bile ducts. The number of activated HSCs was decreased in only one post-Kasai biopsy. TGF-beta1 mRNA expression was demonstrated in bile duct epithelial cells and activated HSCs and in hepatocytes in close proximity to fibrotic septa. Active TGF-beta1 protein was demonstrated in bile duct epithelial cells and activated HSCs. This study provides evidence that activated HSCs are responsible for increased collagen production in patients with biliary atresia and therefore play a definitive role in the fibrogenic process. We have also shown that bile duct epithelial cells, HSCs, and hepatocytes are all involved in the production of the profibrogenic cytokine, TGF-beta1.     

Role of urokinase in the activation of macrophage-associated TGF-beta in silica-induced lung fibrosis

Since tumor growth factor beta (TGF-beta) and its receptor are ubiquitously expressed and because latent TGF-beta cannot bind to the cell surface receptor, the ability of a cell to activate latent TGF-beta upon secretion represents an important regulatory mechanism of TGF-beta action. In vivo, the protease plasmin is considered to be one of the main enzymes operative in the proteolytic cleavage of the latency-associated peptide moiety from TGF-beta, which converts it into the biologically active form. The TGF-beta response was characterized in alveolar macrophages during pulmonary inflammation (d 3) and fibrosis (d 120) induced by a single intratracheal instillation of silica particles (5 mg/mouse). To appreciate the role of urokinase-type plasminogen activator (uPA) in the activation of TGF-beta, the production of total, active and latent TGF-beta by explanted alveolar macrophages was compared in uPA-deficient (uPA-/-) mice and their normal counterparts (uPA+/+). At d 3 and 120 after silica treatment, a significant increase in cell-associated PA activity was found in uPA+/+ mice compared to that of saline controls. As expected, this response was almost totally absent in uPA-/- mice. Alveolar macrophages from uPA+/+ controls were found to release TGF-beta mainly expressed in a biologically active form. In response to silica treatment, inflammatory cells were found to upregulate, especially at the fibrotic stage, their secretion of total and bioactive TGF-beta. No significant difference was found between uPA-/- and uPA+/+ silica-treated animals for the expression of total, active, or latent TGF-beta. Although it has previously been reported that macrophage surface activation of TGF-beta is dependent on both plasmin generation and uPA cell surface receptor, no evidence was found to support this hypothesis in the present study.     

Effects of platelet-activating factor (PAF) receptor blockage on mucous glycoprotein secretion in cultured chinchilla middle ear epithelium

The relationship between liver steatosis, evaluated by ultrasonography, and various plasma haemostatic factors was examined in 64 apparently healthy males, aged 38 years. Plasma levels of factor VII clotting activity (F-VIIc), plasminogen activator inhibitor-1 (PAI-1) activity and antigen, tissue-type plasminogen activator (t-PA) activity significantly differed in men with liver steatosis (n = 31) as compared with those without steatosis (n = 33). No significant differences were found in t-PA antigen and F-VII antigen. The men with liver steatosis also had significantly higher body mass index (BMI), plasma triglyceride and 2 h post-load insulin concentrations. While the differences in plasma haemostatic factors were substantially unchanged after adjustment for BMI, they totally disappeared when further allowance was made for plasma triglyceride and 2 h insulin concentrations. In conclusion, these results indicate that liver steatosis correlates specifically with increased PAI-1, F-VIIc and decreased t-PA levels, and suggest that such a relation is largely mediated by concomitant alterations in plasma triglyceride and insulin concentrations.     

The study of individual differences as a method for dividing into stages the acquisition of a complex reflex

Cultured hepatic stellate cells (HSCs), the cell type primarily involved in the progression of liver fibrosis, secrete insulin-like growth factor-I (IGF-I) and IGF binding protein (IGFBP) activity. IGF-I exerts a mitogenic effect on HSCs, thus potentially contributing to the fibrogenic process in an autocrine fashion. However, IGF-I action is modulated by the presence of specific IGFBPs that may inhibit and/or enhance its biologic effects. Therefore, we examined IGFBP-1 through IGFBP-6 mRNA and protein expression in HSCs isolated from human liver and activated in culture. Regulation of IGFBPs in response to IGF-I and other polypeptide growth factors involved in the hepatic fibrogenic process was also assessed. RNase protection assays and ligand blot analysis demonstrated that HSCs express IGFBP-2 through IGFBP-6 mRNAs and release detectable levels of IGFBP-2 through IGFBP-5. Because IGF-I, platelet-derived growth factor-BB (PDGF-BB), and transforming growth factor-beta (TGF-beta) stimulate HSC proliferation and/or matrix production, we tested their effect on IGFBPs released by HSCs. IGF-I induced IGFBP-3 and IGFBP-5 proteins in a time-dependent manner without an increase in the corresponding mRNAs. IGFBP-4 protein levels decreased in response to IGF-I. TGF-beta stimulated IGFBP-3 mRNA and protein but decreased IGFBP-5 mRNA and protein. In contrast, PDGF-BB failed to regulate IGFBPs compared with controls. Recombinant human IGFBP-3 (rhIGFBP-3) was then tested for its effect on IGF-I-induced mitogenesis in HSCs. rhIGFBP-3 inhibited IGF-I-stimulated DNA synthesis in a dose-dependent manner, with a peak effect observed at 25 nM IGFBP-3. Because TGF-beta is highly expressed in cirrhotic liver tissue, we determined whether IGFBP-3 mRNA expression is increased in liver biopsies obtained from patients with an active fibroproliferative response due to viral-induced chronic active hepatitis. In the majority of these samples, IGFBP-3 mRNA was increased compared with normal controls. These findings indicate that human HSCs, in their activated phenotype, constitutively produce IGFBPs. IGF-I and TGF-beta differentially regulate IGFBP-3, IGFBP-4, and IGFBP-5 expression, which, in turn, may modulate the in vitro and in vivo action of IGF-I.