{"title":"Perspectives: on being a visiting scientist.","authors":"R. Zhao","doi":"10.1067/MLC.2002.123659","DOIUrl":"https://doi.org/10.1067/MLC.2002.123659","url":null,"abstract":"","PeriodicalId":23085,"journal":{"name":"The Journal of laboratory and clinical medicine","volume":"16 1","pages":"192-3"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84292141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Investigations on the effects of serotonin (5-HT) and the serotonin transporter (5-HTT) on the pulmonary circulation are of special interest because of the reported increased risk of primary pulmonary hypertension (PPH) in patients who used some appetite suppressants that interfere with 5-HT. In addition to its vasoactive effects, 5-HT exerts mitogenic and comitogenic effects on pulmonary artery smooth muscle cells (PASMCs). These mitogenic and comitogenic effects require 5-HT internalization by the high-affinity 5-HTT, which can be competitively inhibited by specific drugs such as fluoxetine and paroxetine. In a recent study, we showed that hypoxia increases the rate of 5-HTT gene transcription in PASMCs and potentiates the growth-promoting effect of 5-HT on these cells. An increase in the levels of 5-HTT messenger ribonucleic acid was observed in smooth-muscle cells from remodeled pulmonary arteries in rats subjected to long-term hypoxia. Two series of especially relevant data further support the idea that 5-HT plays a key role in PASMC proliferation in vivo: (1) treatments that increase plasma 5-HT levels aggravate pulmonary hypertension in rats subjected to long-term hypoxia, and this effect can be prevented by combined simultaneous treatment with 5-HTT inhibitors; and (2) knockout mice with disruption of the 5-HTT gene exhibit lesser degree of hypoxic pulmonary hypertension and pulmonary vascular remodeling than control mice despite increased hypoxic pulmonary vasoconstriction. These observations indicate that 5-HTT expression, activity, or both in PASMCs contribute to pulmonary vascular remodeling and that the inducing effects of some appetite suppressants on pulmonary hypertension may be related to possible effects of these drugs on 5-HTT expression, activity, or both.
{"title":"Is the serotonin transporter involved in the pathogenesis of pulmonary hypertension?","authors":"S. Eddahibi, B. Raffestin, M. Hamon, S. Adnot","doi":"10.1067/MLC.2002.122181","DOIUrl":"https://doi.org/10.1067/MLC.2002.122181","url":null,"abstract":"Investigations on the effects of serotonin (5-HT) and the serotonin transporter (5-HTT) on the pulmonary circulation are of special interest because of the reported increased risk of primary pulmonary hypertension (PPH) in patients who used some appetite suppressants that interfere with 5-HT. In addition to its vasoactive effects, 5-HT exerts mitogenic and comitogenic effects on pulmonary artery smooth muscle cells (PASMCs). These mitogenic and comitogenic effects require 5-HT internalization by the high-affinity 5-HTT, which can be competitively inhibited by specific drugs such as fluoxetine and paroxetine. In a recent study, we showed that hypoxia increases the rate of 5-HTT gene transcription in PASMCs and potentiates the growth-promoting effect of 5-HT on these cells. An increase in the levels of 5-HTT messenger ribonucleic acid was observed in smooth-muscle cells from remodeled pulmonary arteries in rats subjected to long-term hypoxia. Two series of especially relevant data further support the idea that 5-HT plays a key role in PASMC proliferation in vivo: (1) treatments that increase plasma 5-HT levels aggravate pulmonary hypertension in rats subjected to long-term hypoxia, and this effect can be prevented by combined simultaneous treatment with 5-HTT inhibitors; and (2) knockout mice with disruption of the 5-HTT gene exhibit lesser degree of hypoxic pulmonary hypertension and pulmonary vascular remodeling than control mice despite increased hypoxic pulmonary vasoconstriction. These observations indicate that 5-HTT expression, activity, or both in PASMCs contribute to pulmonary vascular remodeling and that the inducing effects of some appetite suppressants on pulmonary hypertension may be related to possible effects of these drugs on 5-HTT expression, activity, or both.","PeriodicalId":23085,"journal":{"name":"The Journal of laboratory and clinical medicine","volume":"110 1","pages":"194-201"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79601992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lydia Nikasinovic-Fournier, J. Just, N. Seta, F. Callais, F. Sahraoui, A. Grimfeld, I. Momas
The prevalence of respiratory allergies has increased over the last 20 years, highlighting the need for a simple and noninvasive tool to investigate, in a clinical and epidemiological context, airway-inflammation mechanisms encountered in allergic and inflammatory processes. The nose, as the first region of the respiratory tract to come in contact with airborne pollutants, is easily explored with the use of nasal lavage (NL). We evaluated an NL method for adults and children, along with its reproducibility and capacity to separate different subgroups. NL reproducibility, assessed in 10 healthy, nonsmoking adults on three different occasions, was determined with the use of the intraclass coefficient of correlation for such inflammatory markers as total cell count, albumin, urea, neutrophil elastase, alpha(1)-antitrypsin, interleukin-6, and interleukin-8. Using this NL method, we analyzed nasal markers of 50 healthy adults (smokers and nonsmokers) and 12 healthy children. Our NL method demonstrated high reproducibility with regard to total cell count, albumin, urea, and alpha(1)-antitrypsin (intraclass correlation coefficient > 0.75). Compared with NL results in nonsmokers, NL in heavy smokers revealed significant increased concentrations of total cell counts and interleukin-8 and significant decreased concentrations of interleukin-6. These findings suggest that NL can be used as a tool in the assessment of inflammation because it has the correct reproducibility and can discriminate between heavy smokers and nonsmokers. Moreover, the use of this standardized method in children is feasible.
{"title":"Nasal lavage as a tool for the assessment of upper-airway inflammation in adults and children.","authors":"Lydia Nikasinovic-Fournier, J. Just, N. Seta, F. Callais, F. Sahraoui, A. Grimfeld, I. Momas","doi":"10.1067/MLC.2002.121661","DOIUrl":"https://doi.org/10.1067/MLC.2002.121661","url":null,"abstract":"The prevalence of respiratory allergies has increased over the last 20 years, highlighting the need for a simple and noninvasive tool to investigate, in a clinical and epidemiological context, airway-inflammation mechanisms encountered in allergic and inflammatory processes. The nose, as the first region of the respiratory tract to come in contact with airborne pollutants, is easily explored with the use of nasal lavage (NL). We evaluated an NL method for adults and children, along with its reproducibility and capacity to separate different subgroups. NL reproducibility, assessed in 10 healthy, nonsmoking adults on three different occasions, was determined with the use of the intraclass coefficient of correlation for such inflammatory markers as total cell count, albumin, urea, neutrophil elastase, alpha(1)-antitrypsin, interleukin-6, and interleukin-8. Using this NL method, we analyzed nasal markers of 50 healthy adults (smokers and nonsmokers) and 12 healthy children. Our NL method demonstrated high reproducibility with regard to total cell count, albumin, urea, and alpha(1)-antitrypsin (intraclass correlation coefficient > 0.75). Compared with NL results in nonsmokers, NL in heavy smokers revealed significant increased concentrations of total cell counts and interleukin-8 and significant decreased concentrations of interleukin-6. These findings suggest that NL can be used as a tool in the assessment of inflammation because it has the correct reproducibility and can discriminate between heavy smokers and nonsmokers. Moreover, the use of this standardized method in children is feasible.","PeriodicalId":23085,"journal":{"name":"The Journal of laboratory and clinical medicine","volume":"27 1","pages":"173-80"},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82973566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Platelets are the first cells to adhere to a surface in contact with blood and are capable of mediating several different responses after contact with different protein-coated surfaces. They are the main source of growth factors such as platelet-derived growth factor and are therefore important in the healing process. In this study, initial platelet adhesion to and spread on hydrophilic and hydrophobic (methylized) glass and titanium with similar wettability were investigated. Whole coagulating blood was used to simulate the in vivo situation shortly after implantation, in which bleeding precedes inflammation and wound healing. Several different antibodies directed against platelet integrins and receptors (CD9, FcgammaRII, GPIIb/IIIa, vitronectin receptor, GPIb/V/IX) were used in an attempt to block platelet adhesion to the surfaces. Immunofluorescence results show that initial platelet adhesion to all the surfaces we investigated can be almost completely inhibited (approximately 95%) by clone M148, an antibody against the GPIIb/IIIa complex (integrin alpha(IIb)beta(3); CD41/CD61), but not with other antibodies to the separate parts of the integrin. Antibodies known to inhibit fibrinogen binding to GPIIb/IIIa after adenosine diphosphate- and collagen- induced aggregation had very little effect on initial platelet adhesion. None of the other integrins were found to have such an effect on initial platelet adhesion. Antibody clone M148 was furthermore found to inhibit platelet spreading. This study shows that regardless of wettability and the biomaterial used, initial adhesion of platelets appears to be mediated by GPIIb/IIIa binding to surface adsorbed fibrinogen.
{"title":"GpIIb/IIIa is the main receptor for initial platelet adhesion to glass and titanium surfaces in contact with whole blood.","authors":"M. Broberg, C. Eriksson, H. Nygren","doi":"10.1067/MLC.2002.121604","DOIUrl":"https://doi.org/10.1067/MLC.2002.121604","url":null,"abstract":"Platelets are the first cells to adhere to a surface in contact with blood and are capable of mediating several different responses after contact with different protein-coated surfaces. They are the main source of growth factors such as platelet-derived growth factor and are therefore important in the healing process. In this study, initial platelet adhesion to and spread on hydrophilic and hydrophobic (methylized) glass and titanium with similar wettability were investigated. Whole coagulating blood was used to simulate the in vivo situation shortly after implantation, in which bleeding precedes inflammation and wound healing. Several different antibodies directed against platelet integrins and receptors (CD9, FcgammaRII, GPIIb/IIIa, vitronectin receptor, GPIb/V/IX) were used in an attempt to block platelet adhesion to the surfaces. Immunofluorescence results show that initial platelet adhesion to all the surfaces we investigated can be almost completely inhibited (approximately 95%) by clone M148, an antibody against the GPIIb/IIIa complex (integrin alpha(IIb)beta(3); CD41/CD61), but not with other antibodies to the separate parts of the integrin. Antibodies known to inhibit fibrinogen binding to GPIIb/IIIa after adenosine diphosphate- and collagen- induced aggregation had very little effect on initial platelet adhesion. None of the other integrins were found to have such an effect on initial platelet adhesion. Antibody clone M148 was furthermore found to inhibit platelet spreading. This study shows that regardless of wettability and the biomaterial used, initial adhesion of platelets appears to be mediated by GPIIb/IIIa binding to surface adsorbed fibrinogen.","PeriodicalId":23085,"journal":{"name":"The Journal of laboratory and clinical medicine","volume":"100 1","pages":"163-72"},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79499958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Porcelli, L. Terzuoli, B. Frosi, R. Pagani, L. Montomoli, R. Romeo, P. Sartorelli
{"title":"Blood concentrations of lead and erythropoietin.","authors":"B. Porcelli, L. Terzuoli, B. Frosi, R. Pagani, L. Montomoli, R. Romeo, P. Sartorelli","doi":"10.1067/MLC.2002.121333","DOIUrl":"https://doi.org/10.1067/MLC.2002.121333","url":null,"abstract":"","PeriodicalId":23085,"journal":{"name":"The Journal of laboratory and clinical medicine","volume":"68 1","pages":"125"},"PeriodicalIF":0.0,"publicationDate":"2002-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76858863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Birk, Darya Bubman, M. Broekman, H. Robertson, J. Drosopoulos, A. Marcus, H. Szeto
Ecto- and exoenzymes that metabolize extracellular adenosine diphosphate (ADP), the major promoter of platelet activation and recruitment, are of potential clinical importance because they can metabolically prevent excessive thrombus growth. An ecto-ADPase (CD39, NTPDase1) has been identified on endothelial cells. We demonstrate that ADP and adenosine triphosphate (ATP) are rapidly metabolized to adenosine monophosphate (AMP) in sheep plasma at pH 7.4. This hydrolysis is sensitive to P(1), P(5)-di-(adenosine-5') pentaphosphate (Ap(5)A), and ethylene glycol bis (beta-aminoethyl ether) - N, N, N(-), N(-) tetra-acetate (EGTA) but insensitive to tetramisole (an alkaline phosphatase inhibitor). A specific phosphodiesterase substrate, p -nitrophenol-5'-thymidine monophosphate (TMP) (p -Nph-5'-TMP), was readily hydrolyzed in sheep plasma at a rate of approximately 0.25 nmol/min/mg protein, and this hydrolysis was inhibited by ADP, ATP, and Ap(5)A. Furthermore, 200-fold purified p -Nph-5'-TMP-hydrolyzing activity also hydrolyzed ATP and ADP directly to AMP. When ADP was preincubated in plasma, its ability to induce platelet aggregation was inhibited in a time-dependent manner. This effect was abolished by Ap(5)A. The inhibitory effects on platelet aggregation correlated with hydrolysis of the ADP in plasma. These data suggest that the endogenous soluble plasma phosphohydrolase metabolizes ATP and ADP by means of cleavage of the alpha-beta-phosphodiester bond of nucleoside 5'-phosphate derivatives. This novel biochemical activity inhibits platelet reactivity through hydrolysis of extracellular nucleotides released by activated platelets during (patho)physiological processes, serving a homeostatic and antithrombotic function in vivo.
代谢细胞外二磷酸腺苷(ADP)的外泌酶和外泌酶是血小板活化和募集的主要启动子，它们具有潜在的临床重要性，因为它们可以代谢防止血栓过度生长。在内皮细胞上发现了一种外泌adpase (CD39, NTPDase1)。我们证明了ADP和三磷酸腺苷(ATP)在pH为7.4的绵羊血浆中迅速代谢为一磷酸腺苷(AMP)。这种水解对P(1)， P(5)-二-(腺苷-5')五磷酸(Ap(5)A)和乙二醇双(β -氨基乙醚)- N, N, N(-)， N(-)四乙酸酯(EGTA)敏感，但对四唑(一种碱性磷酸酶抑制剂)不敏感。一种特殊的磷酸二酯酶底物对硝基苯酚-5′-胸苷单磷酸(p -Nph-5′-TMP)在绵羊血浆中以大约0.25 nmol/min/mg蛋白的速率容易水解，这种水解被ADP、ATP和Ap(5)A抑制。此外，200倍纯化的p -Nph-5'- tmp水解活性还能将ATP和ADP直接水解为AMP。当ADP在血浆中预孵育时，其诱导血小板聚集的能力以时间依赖性的方式受到抑制。这种效应被Ap(5)A所消除。对血小板聚集的抑制作用与血浆中ADP的水解有关。这些数据表明内源性可溶性血浆磷酸水解酶通过裂解核苷5'-磷酸衍生物的α - β -磷酸二酯键来代谢ATP和ADP。这种新的生化活性通过水解活化血小板在(病理)生理过程中释放的细胞外核苷酸来抑制血小板反应性，在体内具有稳态和抗血栓功能。
{"title":"Role of a novel soluble nucleotide phospho-hydrolase from sheep plasma in inhibition of platelet reactivity: hemostasis, thrombosis, and vascular biology.","authors":"A. Birk, Darya Bubman, M. Broekman, H. Robertson, J. Drosopoulos, A. Marcus, H. Szeto","doi":"10.1067/MLC.2002.121334","DOIUrl":"https://doi.org/10.1067/MLC.2002.121334","url":null,"abstract":"Ecto- and exoenzymes that metabolize extracellular adenosine diphosphate (ADP), the major promoter of platelet activation and recruitment, are of potential clinical importance because they can metabolically prevent excessive thrombus growth. An ecto-ADPase (CD39, NTPDase1) has been identified on endothelial cells. We demonstrate that ADP and adenosine triphosphate (ATP) are rapidly metabolized to adenosine monophosphate (AMP) in sheep plasma at pH 7.4. This hydrolysis is sensitive to P(1), P(5)-di-(adenosine-5') pentaphosphate (Ap(5)A), and ethylene glycol bis (beta-aminoethyl ether) - N, N, N(-), N(-) tetra-acetate (EGTA) but insensitive to tetramisole (an alkaline phosphatase inhibitor). A specific phosphodiesterase substrate, p -nitrophenol-5'-thymidine monophosphate (TMP) (p -Nph-5'-TMP), was readily hydrolyzed in sheep plasma at a rate of approximately 0.25 nmol/min/mg protein, and this hydrolysis was inhibited by ADP, ATP, and Ap(5)A. Furthermore, 200-fold purified p -Nph-5'-TMP-hydrolyzing activity also hydrolyzed ATP and ADP directly to AMP. When ADP was preincubated in plasma, its ability to induce platelet aggregation was inhibited in a time-dependent manner. This effect was abolished by Ap(5)A. The inhibitory effects on platelet aggregation correlated with hydrolysis of the ADP in plasma. These data suggest that the endogenous soluble plasma phosphohydrolase metabolizes ATP and ADP by means of cleavage of the alpha-beta-phosphodiester bond of nucleoside 5'-phosphate derivatives. This novel biochemical activity inhibits platelet reactivity through hydrolysis of extracellular nucleotides released by activated platelets during (patho)physiological processes, serving a homeostatic and antithrombotic function in vivo.","PeriodicalId":23085,"journal":{"name":"The Journal of laboratory and clinical medicine","volume":"66 8 1","pages":"116-24"},"PeriodicalIF":0.0,"publicationDate":"2002-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81697669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Hershko, G. Link, A. Konijn, M. Huerta, E. Rosenmann, C. Reinus
Although the beneficial effects of deferoxamine (DFO) on iron-associated morbidity and mortality are well documented, the role of deferiprone (L1) in the management of transfusional iron overload is controversial. This debate involves not only the question of efficacy but also of safety, with particular emphasis on the risk of a paradoxical aggravation of iron toxicity by L1. We used the iron-loaded gerbil model introduced by Carthew et al to compare the chelating efficacy of L1, DFO, or both in two gerbil strains treated by means of weekly iron-dextran injections: Psammomys obesus and pathogen-free Mongolian gerbils (Meriones unguiculatus). The difference between the high mortality and advanced hepatocellular necrosis observed in iron-loaded P obesus and the absence of mortality and limited morbidity encountered in pathogen-free Mongolian gerbils is most likely explained by the prevention of coincidental laboratory infections in the latter group. Iron-chelating treatment in all experimental groups resulted in a significant decrease in hepatic iron concentrations and normalization of mitochondrial respiratory enzyme activities, with combined L1 and DFO treatment being the most efficient, followed, in decreasing order, by DFO and L1 as single-drug treatments. Judged by tissue iron concentrations, mitochondrial enzyme activity, and hepatic histology, we could find no evidence of a paradoxical aggravation of iron toxicity by L1 in either of the two series of studies. Although these data appear to be reassuring, the present controversy related to the role of L1 in the development of hepatic cirrhosis should be eventually settled by clinical studies evaluating the effects of long-term iron-chelating treatment.
{"title":"The iron-loaded gerbil model revisited: effects of deferoxamine and deferiprone treatment.","authors":"C. Hershko, G. Link, A. Konijn, M. Huerta, E. Rosenmann, C. Reinus","doi":"10.1067/MLC.2002.120364","DOIUrl":"https://doi.org/10.1067/MLC.2002.120364","url":null,"abstract":"Although the beneficial effects of deferoxamine (DFO) on iron-associated morbidity and mortality are well documented, the role of deferiprone (L1) in the management of transfusional iron overload is controversial. This debate involves not only the question of efficacy but also of safety, with particular emphasis on the risk of a paradoxical aggravation of iron toxicity by L1. We used the iron-loaded gerbil model introduced by Carthew et al to compare the chelating efficacy of L1, DFO, or both in two gerbil strains treated by means of weekly iron-dextran injections: Psammomys obesus and pathogen-free Mongolian gerbils (Meriones unguiculatus). The difference between the high mortality and advanced hepatocellular necrosis observed in iron-loaded P obesus and the absence of mortality and limited morbidity encountered in pathogen-free Mongolian gerbils is most likely explained by the prevention of coincidental laboratory infections in the latter group. Iron-chelating treatment in all experimental groups resulted in a significant decrease in hepatic iron concentrations and normalization of mitochondrial respiratory enzyme activities, with combined L1 and DFO treatment being the most efficient, followed, in decreasing order, by DFO and L1 as single-drug treatments. Judged by tissue iron concentrations, mitochondrial enzyme activity, and hepatic histology, we could find no evidence of a paradoxical aggravation of iron toxicity by L1 in either of the two series of studies. Although these data appear to be reassuring, the present controversy related to the role of L1 in the development of hepatic cirrhosis should be eventually settled by clinical studies evaluating the effects of long-term iron-chelating treatment.","PeriodicalId":23085,"journal":{"name":"The Journal of laboratory and clinical medicine","volume":"115 1","pages":"50-8"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80858624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biliary stent placement is a well-established method of relieving obstructive jaundice. However, a frequent complication is occlusion of the stent caused by bacterial biofilm formation and sludge accumulation. In this study we investigated the possible effect of bile mucin on bacterial adherence to biliary stents at the initial stage of biofilm formation. By means of an in vitro bile-perfusion system, polyethylene stents were perfused with pig gallbladder bile infected with Escherichia coli. The concentrations of mucin in the pig bile were adjusted with purified mucin. The amount of bacteria adhering to the inner surface of the stents was measured and compared for stents perfused with bile containing various concentrations of mucin. Furthermore, we conditioned the stent inner surface with purified pig bile mucin and observed the effect of the conditioning on subsequent bacterial adherence. In addition, a common method for assaying bacterial adhesion with polystyrene microtiter plates was also used in this study. The results demonstrated that more bacteria adhered to the inner surface of stents perfused with bile containing 5 mg/mL mucin than of those perfused with bile containing 0.5 and 0 mg/mL mucin. Increased bacterial adherence was demonstrated on the stent surfaces conditioned with purified mucin compared with that seen on the nonconditioned stent surfaces. The optical densities indicating bacterial adhesion in the microtiter plate wells precoated with mucin were higher than those in non-coated plate wells. The in vitro results indicate that when a biliary stent is implanted in vivo, mucin in bile may condition the stent inner surface, modulate subsequent bacterial adherence to the surface, and participate in stent occlusion.
{"title":"Role of bile mucin in bacterial adherence to biliary stents.","authors":"Hongjun Zhang, T. Tsang, C. A. Jack, J. Pollack","doi":"10.1067/MLC.2002.120257","DOIUrl":"https://doi.org/10.1067/MLC.2002.120257","url":null,"abstract":"Biliary stent placement is a well-established method of relieving obstructive jaundice. However, a frequent complication is occlusion of the stent caused by bacterial biofilm formation and sludge accumulation. In this study we investigated the possible effect of bile mucin on bacterial adherence to biliary stents at the initial stage of biofilm formation. By means of an in vitro bile-perfusion system, polyethylene stents were perfused with pig gallbladder bile infected with Escherichia coli. The concentrations of mucin in the pig bile were adjusted with purified mucin. The amount of bacteria adhering to the inner surface of the stents was measured and compared for stents perfused with bile containing various concentrations of mucin. Furthermore, we conditioned the stent inner surface with purified pig bile mucin and observed the effect of the conditioning on subsequent bacterial adherence. In addition, a common method for assaying bacterial adhesion with polystyrene microtiter plates was also used in this study. The results demonstrated that more bacteria adhered to the inner surface of stents perfused with bile containing 5 mg/mL mucin than of those perfused with bile containing 0.5 and 0 mg/mL mucin. Increased bacterial adherence was demonstrated on the stent surfaces conditioned with purified mucin compared with that seen on the nonconditioned stent surfaces. The optical densities indicating bacterial adhesion in the microtiter plate wells precoated with mucin were higher than those in non-coated plate wells. The in vitro results indicate that when a biliary stent is implanted in vivo, mucin in bile may condition the stent inner surface, modulate subsequent bacterial adherence to the surface, and participate in stent occlusion.","PeriodicalId":23085,"journal":{"name":"The Journal of laboratory and clinical medicine","volume":"97 1","pages":"28-34"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77808052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lysophosphatidic acid (LPA) is a glycerophospholipid released from platelets that has multiple biologic effects. The present study evaluated the potential of LPA to modulate tissue repair and remodeling by modifying human lung fibro-blast-mediated contraction of three-dimensional collagen gels. The contraction of native collagen gels caused by human fetal lung fibroblasts was augmented by LPA in a concentration-dependent manner. The estimated median effective concentration was 3 x 10(-7) mol/L, which was well below the concentrations likely released by platelets in tissues. LPA-augmented contraction was not blocked by pertussis toxin or cholera toxin but was inhibited by inhibition of phospholipase C. Neither calcium mobilization nor protein kinase C appeared to play a role. In contrast, the effect of LPA appeared to depend on a kinase inhibited by staurosporine but not by genistein or GF109203X, suggesting a process that depends on phospholipase C and may involve a novel protein kinase. By modulating fibroblast-mediated remodeling, LPA could play a role in the tissue remodeling that characterizes wound repair.
{"title":"Lysophosphatidic acid augments fibroblast-mediated contraction of released collagen gels.","authors":"T. Mio, Xiangde Liu, M. Toews, S. Rennard","doi":"10.1067/MLC.2002.120650","DOIUrl":"https://doi.org/10.1067/MLC.2002.120650","url":null,"abstract":"Lysophosphatidic acid (LPA) is a glycerophospholipid released from platelets that has multiple biologic effects. The present study evaluated the potential of LPA to modulate tissue repair and remodeling by modifying human lung fibro-blast-mediated contraction of three-dimensional collagen gels. The contraction of native collagen gels caused by human fetal lung fibroblasts was augmented by LPA in a concentration-dependent manner. The estimated median effective concentration was 3 x 10(-7) mol/L, which was well below the concentrations likely released by platelets in tissues. LPA-augmented contraction was not blocked by pertussis toxin or cholera toxin but was inhibited by inhibition of phospholipase C. Neither calcium mobilization nor protein kinase C appeared to play a role. In contrast, the effect of LPA appeared to depend on a kinase inhibited by staurosporine but not by genistein or GF109203X, suggesting a process that depends on phospholipase C and may involve a novel protein kinase. By modulating fibroblast-mediated remodeling, LPA could play a role in the tissue remodeling that characterizes wound repair.","PeriodicalId":23085,"journal":{"name":"The Journal of laboratory and clinical medicine","volume":"103 1","pages":"20-7"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88410436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Kohyama, X. Liu, F. Wen, H. J. Kim, H. Takizawa, S. Rennard
Fibroblast production of extracellular matrix is crucial not only for normal tissue development and maintenance of tissue structure but also for the repair and remodeling processes after injury. Thromboxane A(2) (TXA(2)) is a potent mediator in inflammatory processes. The aim of this study was to investigate the effect of TXA(2) on chemotaxis of human fetal lung (HFL-1) fibroblasts induced by human plasma fibronectin or platelet-derived growth factor BB (PDGF-BB). By using the blindwell chamber technique, the TXA(2) agonist U-46619 alone had no chemotactic activity. However, U-46619 (200 nmol/L) stimulated HFL-1 fibroblast chemotaxis to human plasma fibronectin (20 microg/mL; 161.8% +/- 13.4%; P <.005) and to PDGF-BB (10 ng/mL; 188.5% +/- 7.0%; P <.005). Checkerboard analysis of human plasma fibronectin-directed migration confirmed that the TXA(2) agonist increased both chemotaxis and chemokinesis. The stimulatory effect of the TXA(2) agonist was concentration dependent and increased with time. Another agent known for stimulating the protein kinase C pathway, phorbol 12-myristate 13-acetate (10(-8) mol/L), had a similar effect, stimulating chemotaxis to fibronectin (146.2% +/- 8.6%). The stimulatory effect of the TXA(2) agonist on HFL-1 fibroblast chemotaxis was inhibited by the synthetic thromboxane receptor antagonist SQ29,548 (10(-5) mol/L) and the protein kinase C inhibitor calphostin (10(-7) mol/L). In summary, TXA(2) appears to stimulate fibroblast chemotaxis to fibronectin and PDGF, perhaps by modulating the rate of fibroblast migration. Such an effect may contribute to regulation of wound healing and the development of fibrotic disorders.
{"title":"Potentiation of human lung fibroblast chemotaxis by the thromboxane A(2) analog U-46619.","authors":"T. Kohyama, X. Liu, F. Wen, H. J. Kim, H. Takizawa, S. Rennard","doi":"10.1067/MLC.2002.120540","DOIUrl":"https://doi.org/10.1067/MLC.2002.120540","url":null,"abstract":"Fibroblast production of extracellular matrix is crucial not only for normal tissue development and maintenance of tissue structure but also for the repair and remodeling processes after injury. Thromboxane A(2) (TXA(2)) is a potent mediator in inflammatory processes. The aim of this study was to investigate the effect of TXA(2) on chemotaxis of human fetal lung (HFL-1) fibroblasts induced by human plasma fibronectin or platelet-derived growth factor BB (PDGF-BB). By using the blindwell chamber technique, the TXA(2) agonist U-46619 alone had no chemotactic activity. However, U-46619 (200 nmol/L) stimulated HFL-1 fibroblast chemotaxis to human plasma fibronectin (20 microg/mL; 161.8% +/- 13.4%; P <.005) and to PDGF-BB (10 ng/mL; 188.5% +/- 7.0%; P <.005). Checkerboard analysis of human plasma fibronectin-directed migration confirmed that the TXA(2) agonist increased both chemotaxis and chemokinesis. The stimulatory effect of the TXA(2) agonist was concentration dependent and increased with time. Another agent known for stimulating the protein kinase C pathway, phorbol 12-myristate 13-acetate (10(-8) mol/L), had a similar effect, stimulating chemotaxis to fibronectin (146.2% +/- 8.6%). The stimulatory effect of the TXA(2) agonist on HFL-1 fibroblast chemotaxis was inhibited by the synthetic thromboxane receptor antagonist SQ29,548 (10(-5) mol/L) and the protein kinase C inhibitor calphostin (10(-7) mol/L). In summary, TXA(2) appears to stimulate fibroblast chemotaxis to fibronectin and PDGF, perhaps by modulating the rate of fibroblast migration. Such an effect may contribute to regulation of wound healing and the development of fibrotic disorders.","PeriodicalId":23085,"journal":{"name":"The Journal of laboratory and clinical medicine","volume":"67 1","pages":"43-9"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89052589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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