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T Bamba

Publications and source records attributed to T Bamba.

At least 19 recordsLinked to original sources

Interleukin-17 stimulates chemokine (interleukin-8 and monocyte chemoattractant protein-1) secretion in human pancreatic periacinar myofibroblasts.

BACKGROUND: Interleukin (IL)-17 is a newly identified T-cell-derived cytokine that can regulate the functions of a variety of cell types. In this study, we investigated the effects of CD4+ T-cell-derived cytokines on chemokine secretion in human pancreatic periacinar myofibroblasts. METHODS: The secretion of IL-8 and monocyte chemoattractant protein (MCP)-1 was evaluated by ELISA and Northern blot. The expression of IL-17 receptor (R) was analyzed by Northern blot and a binding assay using 125I-labeled IL-17. The activation of nuclear factor-kappaB (NF-kappaB) was assessed by an electrophoretic gel mobility shift assay (EMSA). RESULTS: IL-17 induced a dose-dependent increase in IL-8 and MCP-1 secretion. The effects of IL-17 on IL-8 and MCP-1 mRNA abundance reached a maximum as early as 3 h. and then gradually decreased. IL-17 and IFN-gamma synergistically increased IL-8 secretion and additively enhanced MCP-1 secretion. IFN-gamma induced a weak increase in IL-17R mRNA abundance, but incubation with IFN-gamma for 24 h had no effects on 125I-labeled IL-17-binding, indicating that the co-stimulatory effects of IL-17 and IFN-gamma were not regulated by the modulation of IL-17R expression. Furthermore, IL-17 induced a rapid increase in NF-kappaB DNA-binding activity, and the combination of IL-17 and IFN-gamma further enhanced NF-kappaB DNA-binding activity. CONCLUSIONS: In conclusion, it becomes clear that IL-17 is an inducer of IL-8 and MCP-1 secretion in human pancreatic periacinar myofibroblasts. The combination of IL-17 with IFN-gamma further enhances chemokine secretion. These findings indicate a linkage between T-cell-mediated immunity and inflammatory responses in the pancreas.

Blotting, Northern↗

Application of 2-aminopyridine fluorescence labeling in the analysis of in vivo and in vitro metabolism of dextran sulfate sodium by size-exclusion high-performance liquid chromatography.

The present study describes a size-exclusion high-performance liquid chromatographic method for the separation and quantification of sulfated polysaccharides, such as dextran sulfate sodium (DSS). Pyridylamination of DSS was achieved without difficulty using 2-aminopyridine as a fluorometric label. In addition, 0.1-0.2 M phosphate buffer (pH 3.0) was found to be the mobile phase which produced the best separation. In vitro enzymatic degradation of the pyridylamino-DSS (PA-DSS5000, Mr 5000) using alpha-amylase and the in vivo metabolism in the rat feces after oral administration of PA-DSS5000 were then evaluated. Two small peaks of approximately Mr 380 and 600 appeared after co-incubation with alpha-amylase, indicating PA-DSS5000 may be considerably depolymerized. In vivo, however, PA-DSS5000 excreted in the feces was mainly of PA-DSS5000 polymer. No peaks of less than Mr 5000 were not clearly detectable in the feces because of background fluorescence attributable to gut lumen contents. This method of fluorometric analysis allows fairly selective detection of sulfated polysaccharides in biological materials.

Aminopyridines↗

Oxidative stress increases MICA and MICB gene expression in the human colon carcinoma cell line (CaCo-2).

The human major histocompatibility complex class I chain-related A gene (MICA) and the MICB gene are newly identified members of the major histocompatibility complex class I chain-related gene family. We demonstrate here that oxidative stress, induced by H(2)O(2), promoted MICA (2.2-fold) and MICB (3.8-fold) gene expression using the human colon carcinoma cell line (CaCo-2) and semi-quantitative RT-PCR.

Caco-2 Cells↗

High-resolution analysis of polyprenols by supercritical fluid chromatography.

A high-resolution analysis of polyprenol mixtures was achieved by supercritical fluid chromatography (SFC). The separation of polyprenols was examined on an octadecylsilane-packed column with liquid carbon dioxide as the mobile phase and ethanol as modifier. Using this chromatography system, the resolution of separation (Rs) between octadecaprenol (prenol 18) and nonadecaprenol (prenol 19) was two times higher than that using conventional reversed-phase high-performance liquid chromatography. Our SFC technique allows the advantage of baseline separation of polyprenol samples containing hydrophobic components such as terpenes or fatty acids that are unfavorable for good separation. This method is very useful for the analysis of structurally close polyprenol analogues of rubber plant metabolites.

Chromatography, Liquid↗

Inhibitory effect of troglitazone on glucuronidation catalyzed by human uridine diphosphate-glucuronosyltransferase 1A6.

OBJECTIVE: Troglitazone is a useful new thiazolidinedione oral antidiabetic agent, but it is unpredictably hepatotoxic in about 1.9% of patients. In vitro studies of drug interactions are important in understanding the basis for the pharmacological and toxicological actions of drugs. In the present study, we investigated whether troglitazone inhibits uridine diphosphate (UDP)-glucuronosyltransferase 1A6 (UGT1A6) activity. METHODS: Human cDNA-expressed UGT1A6 was coincubated with troglitazone (inhibitor) and 1-naphthol (substrate). The glucuronidation of 1-naphthol was determined to establish a 50% inhibitory concentration (IC50) and an inhibition (Ki) value. RESULTS: Troglitazone inhibited UGT1A6 activity with an IC50 of 28 microM at a 1-naphthol concentration of 20 microM. The inhibition was a mixed-type mechanism with a Ki value of 20 microM. CONCLUSION: Inhibitory effect of troglitazone is weak, however, co-administration of troglitazone might carry a drug concentration into the toxic range when the concentration approaches a threshold of toxicity by an inherent reduction of UGT1A6 activity.

Chromans↗

Medium-chain triglyceride-rich enteral nutrition is more effective than low-fat enteral nutrition in rat colitis, but is equal in enteritis.

BACKGROUND: Although enteral nutrition (EN) therapy for Crohn's disease has been confirmed to be as effective as steroid therapy, the precise mechanism responsible for the effects of EN remains unclear, although some of the therapeutic effects of EN are believed to be due to a low dietary fat content. In order to elucidate the influence of fat in EN, it is important to investigate not only the quantity of fat, but also the source of the fat. METHODS: We compared two enteral nutritional formulae: Elental (Ajinomoto) (elemental diet; ED), which contains only 1.5% fat, provided as long-chain triglycerides (LCT), versus Twinline (Snow Brand Milk Products) (TL), which contains a high percentage of fat (20.4%), provided mainly as medium-chain triglycerides (MCT). These formulae were tested on rat enteritis and rat colitis induced by trinitrobenzene sulfonic acid (TNBS). RESULTS: Both ED and TL reduced the manifestations of enteritis. TL had a stronger anti-inflammatory effect than ED for colitis. TL also had nutritional advantages as compared with ED, as shown by the total serum protein in the TL group being significantly higher than that in the ED group. CONCLUSION: The results indicate that intraluminal MCT is suitable as a fat energy source during intestinal inflammation in rats. We suggest that Twinline may be more useful to improve nutritional status and to reduce the mucosal inflammation in rat colitis, but that Twinline is equal in effect to Elental for rat enteritis.

Animals↗

The occurrence of geometric polyprenol isomers in the rubber-producing plant, Eucommia ulmoides Oliver.

The chain length and geometric isomerism of polyprenols from Eucommia ulmoides Oliver were analyzed using supercritical fluid chromatography. After intensive effort to establish separation conditions for geometric isomers, a phenyl-bonded silica gel-packed column was found that cleanly separated poly-trans and -cis prenols. The presence of long-chain poly-trans prenols (>9 mers) was confirmed for the first time in plants. Trans isomers were found in the leaf, seed coat, and root, but not in the bark and seed. Poly-trans prenols in this plant may act as intermediates for trans-polyisoprene biosynthesis.

Chromatography, High Pressure Liquid↗

Simultaneous signalling through c-mpl, c-kit and CXCR4 enhances the proliferation and differentiation of human megakaryocyte progenitors: possible roles of the PI3-K, PKC and MAPK pathways.

We assessed the effect of signalling through CXCR4 on the proliferation and differentiation of human megakaryocytic progenitor cells (CFU-Meg) in the presence or absence of stem cell factor (SCF) and/or thrombopoietin (TPO), using peripheral blood-derived CD34(+)IL-6R(-) cells as a target. TPO alone induced a significant number of CFU-Meg colonies. Although stromal cell-derived factor-1 (SDF-1) or SCF alone did not support CFU-Meg colony formation, these factors had a synergistic effect on CFU-Meg colony formation in the presence of TPO. The combination of SDF-1, SCF and TPO induced twice as many CFU-Meg colonies as TPO alone. To investigate the mechanism of this synergistic action, we examined the effects of various protein kinase inhibitors on CFU-Meg colony formation. LY294002 and GF109203X (inhibitors of PI3-K and PKC respectively) completely or partially inhibited this synergistic action. In contrast, a MEK inhibitor (PD98059) did not inhibit CFU-Meg colony formation. It significantly increased the higher ploidy classes (16N to 64N) of megakaryocytes supported by TPO, TPO + SCF, TPO + SDF-1, and TPO + SCF + SDF-1, whereas it abolished the effect of SDF-1 on the increase of higher ploidy classes of megakaryocytes supported by TPO. These results suggest that MAPK may negatively or positively regulate the nuclear maturation of megakaryocytes, known as endomitosis. In the presence of PD98059, proplatelet formation (PPF) was significantly augmented, suggesting that the MAPK pathway may also inhibit the initiation of PPF. In conclusion, simultaneous activation of three signals through c-mpl, c-kit and CXCR4 can induce the in vitro proliferation and differentiation of CFU-Meg, and SDF-1 is a potentiator of human megakaryocytopoiesis.

Cell Cycle Proteins↗

Prevention of murine acute graft-versus-host disease by staphylococcal enterotoxin B treatment.

Retroviral superantigens such as minor lymphocyte stimulating (Mls) antigen play an important role in the pathogenesis of acute graft-versus-host disease (GVHD). However, it remains unclear how exogenous bacterial superantigens modulate acute GVHD. In this study, we tested the effects of staphylococcal enterotoxin B (SEB) on the development of acute GVHD in a model involving the systemic transfer of parental C57Bl/6 spleen cells into BDF1 mice. SEB treatment suppressed the expansion of donor-derived T cells and blocked the decrease in the number of host cells. Impaired haematopoiesis was actually rescued by treatment with SEB. In SEB-treated mice, both spontaneous proliferation and IL-2 production in T cells were suppressed on day 2 after parental cell infusion. On day 21, the number of donor-derived CD4+ Vbeta8+ T cells markedly decreased in the spleen of SEB-treated mice. Donor-derived CD4+ T cells failed to proliferate in response to host alloantigens, and both donor- and host-derived T cells were unable to produce IL-2 in response to concanavalin A stimulation, suggesting that SEB treatment induced a general immunosuppressive state. Our results indicate that SEB treatment prevents the development of acute GVHD by leading to unresponsiveness of donor-derived T cells against host alloantigens in a Vbeta-restricted and unrestricted manner.

Acute Disease↗

Mechanism of NK cell activation induced by coculture with dendritic cells derived from peripheral blood monocytes.

Dendritic cells (DCs) have been regarded as one of the effective antigen-presenting cells, but the relationship between DCs and lymphocytes, in particular natural killer (NK) cells, remains unclear. In this study, we evaluated how DCs interact with both lymphocytes and NK cells using a coculture system. The number of lymphocytes increased significantly when cocultured with DCs (1.8-fold increase). In particular, the proliferation of NK cells was prominent. Furthermore, the coculture of DCs with lymphocytes induced a marked increase in IL-12 and IFN-gamma secretion. When contact between the DCs and lymphocytes was prevented, the secretion of both IL-12 and IFN-gamma was markedly reduced. IFN-gamma production was completely blocked by an anti-IL-12 antibody, indicating that IFN-gamma secretion was dependent on IL-12 secretion. The stimulating effect of the DCs on the proliferation of the lymphocytes was partially suppressed by anti-IL-12 antibodies, and was completely attenuated when cellular contact was prevented. Furthermore, the NK cell proliferation induced by coculture with DCs was significantly blocked by the inhibition of the interaction of either CD40-CD40L or CD28-B7 molecule. The coculture with DCs enhanced NK activity by 40%, and this was partially suppressed by anti-IL-12 antibodies and was completely blocked by the inhibition of cell-to-cell contact. These results indicate that the activation of NK cells by DCs is partially mediated by IL-12 secretion, and that direct contact between DCs and NK cells play a major role in this response.

CD56 Antigen↗

Cooperation of interleukin-17 and interferon-gamma on chemokine secretion in human fetal intestinal epithelial cells.

Interleukin (IL)-17 is a newly identified T cell-derived cytokine that can regulate the functions of a variety of cell types. In this study, we investigated the effects of IL-17 and interferon (IFN)-gamma on chemokine secretion in human fetal intestinal epithelial cells. IL-8 and monocyte chemoattractant protein (MCP)-1 secretion by the human fetal intestinal epithelial cell line, intestine-407, was evaluated by ELISA and Northern blot. The expression of IL-17 receptor (R) was analysed by a binding assay using [(125)I]-labelled IL-17. The activation of nuclear factor-kappa B (NF-kappa B), NF-IL6 and AP-1 was assessed by an electrophoretic gel mobility shift assay (EMSA). IL-17 induced a dose-dependent increase in IL-8 and MCP-1 secretion. The inducing effects of IL-17 on IL-8 and MCP-1 mRNA abundance reached a maximum as early as 3 h, and then gradually decreased. IL-17 and IFN-gamma synergistically increased IL-8 and MCP-1 secretion and mRNA abundance. IFN-gamma induced a weak increase in IL-17 R mRNA abundance, and incubation with IFN-gamma for 24 h enhanced [(125)I]-labelled IL-17-binding by 2.4-fold. IL-17 rapidly induced the phosphorylation and degradation of I kappa B alpha molecules, and the combination of IL-17 and IFN-gamma induced a marked increase in NF-kappa B DNA-binding activity as early as 1.5 h after the stimulation. Furthermore, this combination induced an increase in NF-IL-6 and AP-1 DNA-binding activity. In conclusion, it becomes clear that IL-17 is an inducer of IL-8 and MCP-1 secretion by human fetal intestinal epithelial cells. The combination of IL-17 with IFN-gamma synergistically enhanced chemokine secretion. These effects of IL-17 and IFN-gamma might play an important role in the inflammatory responses in the intestinal mucosa.

Cell Line↗

A case of toxic shock-like syndrome presenting with serious hypoproteinaemia because of a protein-losing gastroenteropathy.

A 37-year-old man was admitted to our hospital because of toxic shock-like syndrome (TSLS) induced by Streptococcus pyogenes. After the pathogenic bacteria had been eradicated, serious diarrhoea appeared and a protein-losing gastroenteropathy developed. An immunohistochemical study of the biopsy specimens of both small and large intestines revealed the infiltration of T-lymphocytes, predominantly CD8+ cells, into the lamina propria of affected mucosa, villus atrophy and crypt hyperplasia. Considering these histological findings, some immunological mechanism which lead the activation of cytotoxic T-lymphocytes may play an important role in the pathogenesis of this rare intestinal manifestation of TSLS.

Adult↗

Dietary fiber fraction of germinated barley foodstuff attenuated mucosal damage and diarrhea, and accelerated the repair of the colonic mucosa in an experimental colitis.

BACKGROUND AND AIMS: Germinated barley foodstuff (GBF) contains protein and insoluble dietary fiber. We have previously shown in ulcerative colitis patients and a colitis model that GBF feeding attenuates mucosal damage by increasing luminal butyrate levels. However, the detailed mechanism remains unclear because of its heterogeneous nature. The present study was carried out to: (i) evaluate the active ingredient in GBF; and (ii) examine its effect on the repair process in colonic inflammation by using a dextran sulfate sodium (DSS) colitis model. METHODS: Colitis was induced by feeding a diet containing 0.5-3.5% DSS to male Sprague-Dawley rats. (i) Active ingredient: GBF was fractionated enzymatically into fiber- and protein-rich fractions. Each fraction was administered to DSS-colitis rats. Clinical signs, cecal short chain fatty acid concentrations and serum alpha1-acid glycoprotein (AAG) levels were determined. (ii) Effect on mucosal repair: GBF with or without salazosulfapyridine (SASP), or SASP alone was administered to rats after the onset of colitis. Seven days after initial treatment, the number of epithelial cells in HE sections was evaluated morphologically in a blind fashion and serum AAG was determined. RESULTS: (i) Germinate barley foodstuff and GBF-fiber significantly attenuated the clinical signs of colitis and decreased serum AAG levels, with a significant increase in cecal butyrate production, while GBF-protein did not. (ii) Treatment with GBF alone and GBF plus SASP significantly accelerated colonic epithelial repair and improved clinical signs. CONCLUSIONS: These findings suggest that the fiber fraction of GBF may effectively enhance luminal butyrate production, and thereby accelerate colonic epithelial repair in colitis.

Animals↗

Evaluation of intestinal mucosal function by measuring expired (14)CO(2) after oral administration of (14)C-putrescine.

BACKGROUND: Diamine oxidase (DAO) is the enzyme that degrades putrescine, the key main product of polyamine metabolism, and reflects enterocytic maturity of absorption because diamine oxidase activity is highest in the small intestine. We have already shown that expired (14)CO(2) after oral administration of (14)C-putrescine correlated with intestinal DAO activity. However, the influence of food composition and the mucosal adaptation after intestinal resection have not been elucidated. METHODS: Male Wistar rats were fed normal chow or an elemental diet (ED) for 2 weeks. Resected rats underwent 50% jejunectomy or 50% ilectomy. Expired (14)CO(2) levels, following oral administration of (14)C-putrescine were measured in all rats, and compared with the intestinal DAO activity and other mucosal parameters. RESULTS: In the ED group, the (14)CO(2) levels reached a peak earlier, and values were 2.9-fold higher than in the group fed with normal chow. Mucosal alkaline phosphatase (ALP) and DAO activity in the ED group were also higher than in the group fed normal chow, although the mucosal wet weight was significantly lower in the ED group. In the resection groups, all expired (14)CO(2) values increased during measurement. The peak (14)CO(2) values in the jejunectomy group shifted earlier in the postoperative period. The mucosal DAO activity in both the resection groups was higher than it was in the control group at the fifth and 10th postoperative day. However, there were no differences among the three groups at the 15th postoperative day. CONCLUSIONS: Our studies suggested that expired (14)CO(2) after oral administration of (14)C-putrescine correlates with mucosal DAO activity, and that it also reflects intestinal function.

Administration, Oral↗

Ligation of the Fas antigen stimulates chemokine secretion in pancreatic cancer cell line PANC-1.

BACKGROUND AND AIM: The role of chemokines in the process of immune cell infiltration into pancreatic cancer tissue has been reported. In this study, we investigated the induction of chemokines (interleukin (IL)-8 and monocyte chemoattractant protein (MCP)-1) by Fas antigen (Ag)-stimulation in a human pancreatic cancer cell line, PANC-1. METHODS: The chemokine secretion was evaluated by using an ELISA and a northern blot, and the activation of nuclear factor-kappa B (NF-kappa B) was assessed by using an electrophoretic gel mobility shift assay (EMSA). RESULTS: The Fas antigen (Ag) stimulation clearly induced an increase in IL-8 and MCP-1 secretion in PANC-1 cells. This effect was also observed at the mRNA level. The induction of chemokine secretion by Fas Ag stimulation required de novo gene expression and protein synthesis. The pretreatment with interferon (IFN)-gamma markedly enhanced the effects of Fas Ag stimulation; IFN-gamma pretreatment and Fas Ag stimulation synergistically induced not only apoptosis but also IL-8 and MCP-1 secretion. Flow cytometric analysis demonstrated that IFN-gamma significantly enhanced Fas Ag expression. In addition, Fas Ag stimulation actually evoked NF-kappa B activation in this cell line. CONCLUSION: Our results indicate that Fas Ag stimulation can induce chemokine secretion in PANC-1 cells, suggesting the contribution of Fas stimulation to the accumulation of immune cells in pancreatic cancer tissue.

Adenocarcinoma↗

Sequential changes in luminal microflora and mucosal cytokine expression during developing of colitis in HLA-B27/beta2-microglobulin transgenic rats.

BACKGROUND: Transgenic rats expressing HLA-B27 and human beta2-microglobulin (HLA-B27 rats) spontaneously develop chronic colitis resembling human inflammatory bowel disease. We investigated the sequential changes in the luminal bacterial flora and mucosal cytokine mRNA expression in this model. METHODS: HLA-B27 rats were maintained in a specific pathogen-free environment, and luminal microflora was evaluated by standard bacterial culture technique. The expression of mucosal cytokine mRNA was analysed by RT-PCR methods. RESULTS: Clinical symptoms of colitis appeared at 8 weeks of age. The total number of obligate anaerobes was higher than those of facultative anaerobes during the experimental period. At 6 weeks of age, the colonization of Bacteroides spp., Bifidobacterium spp. and Lactobacillus spp. was already detectable at high concentrations, whereas Clostridium spp. and Eubacterium spp. were not detected. The expression of proinflammatory cytokines (IL-Ibeta, IL-8 and TNF-alpha) appeared at 8 weeks of age, and these were detectable until 17 weeks. A similar pattern was observed in the expression of Th1 cytokines (IL-2, IL-12 and IFN-gamma). On the other hand, the expression of Th2 cytokines (IL-4, IL-10 and TGF-beta) was weak. IL-4 mRNA expression was weakly detectable only at 6 and 8 weeks of age. The expression of IL-10 and TGF-beta mRNA was scarcely detectable throughout the experimental period. CONCLUSION: The development of colitis may be mediated by both the predominant expression of Th1 cytokines and the weakness of Th2 cytokine expression in the mucosa. The colonization of anaerobic bacteria, especially Bacteroides spp., may be initiating and promoting these cytokine responses.

Animals↗

Hydrophilic and hydrophobic bile acids exhibit different cytotoxicities through cytolysis, interleukin-8 synthesis and apoptosis in the intestinal epithelial cell lines. IEC-6 and Caco-2 cells.

BACKGROUND: Bile acids have been shown to exhibit varying degrees of cytotoxicity, depending on their hydrophobic-hydrophilic balance. We have recently reported the strong cytotoxicity of hyodeoxycholic acid (HDCA), and the aim of the present study is to investigate the mechanisms underlying the cytotoxicity of HDCA. METHODS: The intestinal cell lines IEC-6 and Caco-2 cells were used. The cytotoxicities of various bile acids were evaluated using the MTS assay; their cytolytic effects were measured using the LDH release assay. The induction of apoptosis was determined by the specific figure changes in the cellular cytoplasm and nucleus, including DNA ladder formations. IL-8 synthesis induced by the bile acids was measured using an ELISA assay. RESULTS: The bile acids induced cytotoxic effects, LDH release, IL-8 synthesis and apoptosis, depending on their hydrophobic properties. On the other hand, HDCA induced strong cytotoxicity, apoptosis and IL-8 synthesis but not cytolysis, although HDCA has a hydrophilic nature. In addition, HDCA exerted the strongest effects on dispersing monolayer cells. CONCLUSIONS: These results strongly suggest that HDCA induces cytotoxicity through its ability to induce apoptosis rather than its detergent effect.

Apoptosis↗

Effects of synthetic serine protease inhibitors on proliferation and collagen synthesis of human pancreatic periacinar fibroblast-like cells.

Protease inhibitors are currently used as therapeutic agents for chronic pancreatitis in Japan. We previously reported that human pancreatic periacinar fibroblast-like cells (hPFCs) could be cultured from isolated pancreatic acini, and those are thought to play a crucial role in pancreatic fibrosis correlating with platelet-derived growth factor (PDGF) and transforming growth factor beta1 (TGF-beta1) (Pancreas 1997;14: 373-82). The present study was designed to examine the effects of synthetic serine protease inhibitors (FOY-007 and FOY-305) on proliferation and collagen synthesis of hPFCs under cytokine stimulation. The cell proliferation and collagen synthesis were evaluated using assays of [3H]-thymidine incorporation and procollagen type I c-terminal peptide (PIP), and [14C]-proline incorporation to de novo synthesized collagen, respectively. The cell proliferation stimulated by PDGF was inhibited by the application of FOY-007 dose dependently (1-100 microM) and FOY-305 at 100 microM. FOY-007 attenuated the collagen synthesis and PIP production stimulated by TGF-beta1 dose dependently, but FOY-305 inhibited only PIP production. Both protease inhibitors demonstrated no effect on the proliferation and collagen synthesis of hPFCs when they were not stimulated by PDGF or TGF-beta1. Thus, serine protease inhibitors act on hPFCs to diminish the effects of PDGF on proliferation and the effects of TGF-beta1 on collagen synthesis.

Cell Division↗