Variability and genetic basis for migratory behaviour in a spring population of the aphid, Aphis gossypii Glover in the Yangtze River Valley of China

The population dynamics, development of gonads, takeoff and flight behaviour of Aphis gossypii Glover were investigated in order to test whether there was variation of migratory ability in the spring population. Field surveys showed that not all the aphids overwintering on hibiscus migrated to the secondary host plants, and the host-alternating and host-specific life-cycle forms coexisted in Nanjing, China. Substantial variation in flight capacity of winged individuals, development of gonads and takeoff behaviour were found within the spring population. The frequency distribution of flight duration and the number of ovarioles per individual alatae exhibited two peaks, representing the migratory and sedentary genotypes, respectively. Significant response to directional selection on takeoff behaviour demonstrated the additive genetic component of this variation. Selection for 'takeoff' individuals caused a significant increase in takeoff angle from 39.8 degrees in the first selection to 68.7 degrees in the fifth; and, hence, screened out the migratory genotype (M), while selection for the sedentary individuals increased the rate of non-takeoffs significantly, and screened out the sedentary genotype (S). The reciprocal cross, M(female) x S(male), produced hybrid offspring performing significantly steeper takeoff angles compared with those from the cross S(female) x M(male), suggesting the presence of a maternal effect. On the other hand, takeoff rate was ranked as M(female) x S(male)=S(female) x M(male)>M>S, involving no sex-linkage and maternal effect. The coexistence of host-alternating and host-specific life-cycle forms of A. gossypii on the primary host has, as deduced from the present studies, a genetic basis.

[Evaluation on the indirect economic burden of stroke using combination of disability-adjusted life years and human capital method]

OBJECTIVE

Using the indirect economic burden of stroke in a rural population to develop rational allocation of future health resources, in Hanzhong area.

METHODS

Cluster sampling which involved 53 natural villages with a total number of 75,000 people selected from the 'stroke monitoring base' of rural population was adopted in this study in the Hanzhong area. All of the 164 stroke cases were studied through a self-designed questionnaire. In calculating disability-adjusted life years (DALYs), fixed value was used in accordance with the value of GBD. The disability assessment was simplified in DALYs calculation and modified Barthel's ADL was used in disability assessment of stroke patients. In indirect economic burden analysis, the human capital method combined with DALYs was adopted with the formula as: indirect economic burden = GNP per capita x DALYs x productivity weight.

RESULTS

The total DALYs were 598.88, with an average DALY of stroke as 3.65 per case. The total indirect economic burden of stroke patients in rural areas was 1,993,977.8 RMB and the average of indirect economic burden of stroke was 12,158.4 RMB per case with the largest seen in the 45-59 age group, accounted for 74.4%.

CONCLUSION

In our study, the use of method in combining the human capital with DALYs was the first time being adopted in calculation of the indirect economic burden of stroke in rural population in China. The burden seemed to be much lower than literature cited from other countries. It was reasonable to evaluate indirect economic burden of stroke using method in integrating DALYs with human capital, but it was difficult to calculate the DALYs.

Identification of genetic differences between two clinical isolates of Streptococcus mutans by suppression subtractive hybridization

Streptococcus mutans is generally considered to be the principal aetiological agent for dental caries. Phenotypic variation in strains is often associated with differences in gene content, so the isolation of DNA fragments from these genes or associated regions is illuminating. The S. mutans strains 9-1 and 9-2, which both colonized the same oral cavity, were selected after screening for the possession of suspected virulence traits. Genomic DNA of strain 9-1 was used as the tester, and that of 9-2 was used as the driver. Suppression subtractive hybridization (SSH) was applied between the tester and the driver DNAs. The subtractive products were cloned into a pCR2.1 vector. Clone libraries representing sequence differences were obtained. The subtractive fragments that were found specifically in strain 9-1 but not in strain 9-2 were identified by dot blotting and then sequenced. BLASTn and BLASTx sequence homology analyses were subsequently performed. Twenty-seven sequences were found in the genome of strain 9-1 that were not in 9-2. Among them, three revealed no homology to published nucleotide sequences while the remaining sequences showed 81-100% homology to known genes of S. mutans strain UA159. These sequences are involved in competence development, signal transduction and transcriptional regulation, repairing stress damage, transport, carbohydrate catabolism, biochemical synthesis, or unknown functions. Differences exist in the genomes of different S. mutans isolates. SSH is effective in screening for S. mutans strain specific DNA sequences.

Gender differences in limonin pharmacokinetics in rats

In the present study, the pharmacokinetics of limonin (LM) were investigated in male and female rats. LM concentrations in the plasma were determined after the oral administration of 36 mg/kg LM or after intravenous (i.v.) injection of LM 3.6 mg/kg respectively. Concentrations in the tissues, urine, feces and bile were also analyzed following the oral administration of 36 mg/kg of the test product. It was found that the plasma concentrations of LM in female rats were significantly higher (P < 0.01) than those in male rats. Assessment of the effects of limonin based on the C(max) and AUC in female rats showed that levels were about 50-fold higher than those in male rats after oral administration of 36 mg/kg LM. Furthermore, after i.v. administration of 3.6 mg/kg LM, the C(max) and AUC in female rats was found to be about 3-fold higher than those in male rats. The total excretion of LM in the urine and bile of female rats was also found to be significantly higher than in male rats, which displayed lower concentrations of LM in the tissues, amounting to around one-half to one-tenth of those in female rats, apart from levels in the rectum and duodenum. In conclusion, the present results demonstrate the existence of marked gender difference in LM pharmacokinetics in rats.

Red blood cells increase secretion of matrix metalloproteinases from human lung fibroblasts in vitro

Tissue remodeling is an important process in many inflammatory and fibrotic lung disorders. RBC may in these conditions interact with extracellular matrix (ECM). Fibroblasts can produce and secrete matrix components, matrix-degrading enzymes (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Imbalance in matrix synthesis/degradation may result in rearrangement of tissue architecture and lead to diseases such as emphysema or fibrosis. Neutrophil elastase (NE), a protease released by neutrophils, is known to activate MMP. We hypothesized that RBC can stimulate secretion of MMPs from human lung fibroblasts and that NE can augment this effect. Human fetal lung fibroblasts were cultured in floating collagen gels with or without RBC. After 4 days, the culture medium was analyzed with gelatin zymography, Western blot, and ELISA for MMP-1, -2, -3 and TIMP-1, -2. RBC augmented NE-induced fibroblast-mediated collagen gel contraction compared with NE alone (18.4+/-1.6%, 23.7+/-1.4% of initial gel area, respectively). A pan-MMP inhibitor (GM-6001) completely abolished the stimulating effect of NE. Gelatin zymography showed that RBC stimulated MMP-2 activity and that NE enhanced conversion to the active form. Addition of GM-6001 completely inhibited MMP-2 activity in controls, whereas it only partially altered RBC-induced MMP activity. Western blot confirmed the presence of MMP-1 and MMP-3 in fibroblasts stimulated with RBC, and ELISA confirmed increased concentrations of pro-MMP-1. We conclude that stimulation of MMP secretion by fibroblasts may explain the ability of RBC to augment fibroblast-mediated collagen gel contraction. This might be a potential mechanism by which hemorrhage in inflammatory conditions leads to ECM remodeling.

Correlation between quinolone uptakes by BCECs in vitro and brain-to-plasma concentration ratios in rats

Transport of 11 quinolones at the blood-brain barrier (BBB) was studied in vitro by using primarily cultured rat brain capillary endothelial cells (BCECs) and in vivo brain-to-plasma concentration ratios. In vitro, when cells reached confluence, a time course of quinolone uptake was recorded by incubation with a medium contraining quinolones 20 microg/ml at 37 degrees C. A simple two-compartment model was used for fitting the uptake time course and corresponding uptake parameters were estimated. In vivo rats were anesthetized, after in 10 mg/kg of quinoloes followed by infusion of 4 mg/kg/h for 2 hours, the drug concentrations in plasma and brain were measure and brain-to-plasma concentration ratios were calculated. Result showed that sparfloxacin and prulifloxacin have higher uptakes by BCECs and brain-to-plasma concentration ratios, compared with other quinolones, which indicated that the two drugs more easily penetrate into BBB. A good correlation between uptakes by BCECs and brain-to-plasma concentration ratios was found. These results demonstrated uptakes by BCECs in vitro might give prediction of brain-to-plasma ratio for quinolones.

Different effect of erythromycin on absorption kinetics of nimodipine in male and female rats

Effect of erythromycin (ERY) on oral absorption of nimodipine (NMD) in female and male rat was investigated in vivo and in vitro. In vivo, at 15 min following oral dose of 50 mg/kg ERY, an oral dose 20 mg/kg NMD was given to rats, plasma concentrations of NMD were determined. In vitro, everted jejunum sac and ileum sac were used, NMD transport from mucosal side to serol side was measured, in absences of ERY and cyclosprin A (CSA) or in presence of ERY and CSA. Large gender difference was found after oral dose NDM. Male rats had lower plasma concentration than female rat did. AUC180 and Cmax in male rats were less than 5-folds and 3-folds than those in female rats, respectively. Co-administrating ERY may increase plasma concentrations of NMD in rats. AUC180 in male rats and female rats were 2.2-folds and 1.9-folds of those NMD alone, respectively. Cmax was about 3-folds of that NMD alone. The NMD transport in intestine showed a regional variation and gender differences. In female rat, transport rate in the jejunum was about 1.3 higher than ileum. Both ERY and CSA significant increases transport of NMD. Contrast to female, NMD transport in jejunum was lower that that in ileum. Bothe ERY and CSA had little effect on NMD transport in intestine. These results indicated that there existed gender difference in oral absorption of NMD and effect of ERY on oral absorption kinetics of NMD in female rats was different from that in male rat.

Effect of P-glycoprotein inhibitors erythromycin and cyclosporin A on brain pharmacokinetics of nimodipine in rats

Effect of P-glycoprotein (P-gp) inhibitors erythromycin (Ery) and cyclosporin A(CsA) on brain pharmacokinetics of nimodipine (NMD) in rats was studied. NMD concentrations in rat plasma and brain were determined after iv 2 mg/kg NMD alone, co-administration with Ery and CsA, respectively. It was found that concentrations of NMD in plasma of the three groups had a little difference, but brain concentrations of NMD in rats co-administrated with Ery and CsA were significantly higher than those in rats NMD alone. Significances of NMD in rat brain were found at 20, 40, 60 and 90 min after iv NMD. The brain T(1/2) in rat treated with ery(75.0 min) and CsA(79.0 min) were larger than that (44.2 min) in rats NMD alone. The results indicated that P-gp inhibitors Ery and CsA may increase concentration in rat brain by inhibiting elimination of NMD from brain.

Isospin diffusion and the nuclear symmetry energy in heavy ion reactions

Using symmetric 112Sn+112Sn, 124Sn+124Sn collisions as references, we probe isospin diffusion in peripheral asymmetric 112Sn+124Sn, 124Sn+112Sn systems at an incident energy of E/A=50 MeV. Isoscaling analyses imply that the quasiprojectile and quasitarget in these collisions do not achieve isospin equilibrium, permitting an assessment of isospin transport rates. We find that comparisons between isospin sensitive experimental and theoretical observables, using suitably chosen scaled ratios, permit investigation of the density dependence of the asymmetry term of the nuclear equation of state.

Expression of butyrate response factor 1 in HTLV-1-transformed cells and its transactivation by tax protein

Tax oncoprotein of Human T-lymphotropic virus 1 (HTLV-1) has been proposed to dysregulate the expression of a number of cellular genes, many of which play a critical role for cell proliferation. Our initial data demonstrated that the immediate-early gene butyrate response factor 1 ( BRF1) was upregulated in HTLV-1-infected cells. The ensuing studies revealed that the effect of Tax was mediated through two transcription elements. The more proximal element, located in the vicinity of TATA box, accounted for the main Tax transactivating effect, and it appeared to be a novel transcription factor-binding site. It involved the CCTCCTC sequence (nt -59/-53, relative to transcription start site) and was dubbed BRF1 Tax-responsive site (BTRS). The cellular protein(s) recruited into the formation of DNA-protein complex at this binding site were not identified. The other element, located further upstream, was a consensus cAMP-responsive site (CRE) TGACGTCA, spanning positions -400 to -393. CRE-binding protein (CREB) was found to mediate the transactivating effect of Tax at this site. Our results present the first evidence that the Tax transactivator has a capability to modulate the expression of BRF1 and that this effect is mediated by CRE and a novel BTRS motifs.

Atmospheric aerosol concentration level and chemical characteristics of water-soluble ionic species in wintertime in Beijing, China

Total suspended particulate (TSP) samples were collected during wintertime from November 24, 1998 to February 12, 1999 in Beijing. Ionic species including Cl-, NO3(-), SO4(2-), Na+, NH4(+), K+, Mg2+ and Ca2+ were determined by Ion Chromatography (IC). The sum average concentration of all the determined ions accounted for 18.9% of the TSP concentration, and SO4(2-) appeared the dominant ion with an average concentration of 30.84 microg m(-3); the sum mass concentration of SO4(2-), NO3(-), Ca2+ and NH4(+) accounted for about 83.2% of all the eight ions measured. The study indicated that the chemical form of sulfate and ammonium varies with TSP concentration levels. During heavy pollution periods, the average TSP concentration was 0.66 mg m(-3), and the NH4(+)/SO4(2-) molar ratio was low (0.58). It indicated that sulfate may present as CaSO4 and (NH4)2SO4 x CaSO4 x 2H2O. When TSP concentration (average 0.186 mg m(-3)) was relatively low, the NH4(+)/SO4(2-) molar ratio was 1.94, close to the theoretical ratio of 2 of (NH4)2SO4. Under this condition (NH4)2SO4 is expected to exist as the major form of sulfate. When the TSP concentration level was medium (average 0.35 mg m(-3)), the NH4+/SO4(2-) molar ratio appeared an average value (1.27), (NH4)2SO4, (NH4)2SO4 x CaSO4 x 2H2O and CaSO4 are expected to be present in those aerosol particles. Meteorological conditions including wind speed and wind direction were related to the TSP concentration level.

Red blood cells stimulate human lung fibroblasts to secrete interleukin-8

Following lung injury, red blood cells (RBC) may interact with extracellular matrix (ECM). Fibroblasts, the resident cell in the ECM, have the capacity to produce and secrete a variety of mediators including interleukin-8 (IL-8). In the present study we hypothesized that RBC, or soluble factors released from them, may stimulate IL-8 production by fibroblasts. Fibroblasts were cultured in a three-dimensional collagen gel culture system in the presence or absence of RBC or conditioned medium from RBC (RBC-CM). IL-8 release from fibroblasts was significantly increased when cultured with RBC or RBC-CM and both tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) further stimulated this IL-8 secretion. The enhanced production of IL-8 within fibroblasts was accompanied by increased IL-8 mRNA expression. To evaluate whether RBC-fibroblast interaction may lead to recruitment of neutrophils, a functional migration assay was performed. RBC and RBC-CM, in the presence of IL-1beta and TNF-alpha, increased the transmigration of neutrophils. Our results indicate that RBC, when interacting with ECM, may participate in the recruitment of inflammatory cells by stimulating fibroblasts to secrete IL-8. This might be an important mechanism regulating tissue repair after injury.

Gender difference in ranolazine pharmacokinetics in rats

Pharmacokinetics of ranolazine (RAN) in both female and male rats was studied. RAN concentrations in plasma were determined after oral administration of 12.5, 25 and 50 mg/kg RAN. Concentrations in tissues, recoveries of RAN in urine and bile were also analyzed following oral dose of 25 mg/kg. It was found that plasma concentrations of RAN in female rats were significantly higher than those in male rats. Drug exposures based on Cmax and AUC in female rats were roughly 2-to 3-fold of those in male rats. Terminate half-life T1/2 and MRT in male rats were shorter than those in female rats. The recoveries in urine and bile of female rats were also markedly higher than those in male rats'. Tissue concentrations of RAN in female rats were also markedly higher than those in male rats. These results demonstrated existence of marked gender difference in RAN pharmacokinetics in rats.

Characterization of structure and diffusion behaviour of Ca-alginate beads prepared with external or internal calcium sources

Ca-alginate beads were prepared with either external or internal calcium sources. The structures of both beads were investigated with the aid of scanning electron microscopy (SEM) and confocal microscopy. It was shown that the beads with internal calcium source had a looser structure and bigger pore size than those with external calcium source. The attempts to interpret the difference were carried out by determining the Ca content within the beads at various times, which indicated that it was the different gelation mechanisms that caused the difference of structures of both beads. Furthermore, it was also found that the diffusion rate of haemoglobin (Hb) within the beads with an internal calcium source was faster than that of the beads with an external one, which was consistent with the observation of their structures.

Red blood cells stimulate fibroblast-mediated contraction of three dimensional collagen gels in co-culture

OBJECTIVE AND DESIGN

Following injury, red blood cells (RBC) may interact with extracellular matrix (ECM). In the present study we hypothesised that RBC, and soluble factors from RBC, might mediate remodelling of ECM by affecting fibroblast-mediated contraction of three dimensional collagen gels.

MATERIALS AND METHODS

Human lung fibroblasts (HFL-1), were cultured together with isolated RBC, conditioned medium from RBC (RBC-CM) and hemolysed RBC in type I collagen gels. Gel contraction was determined by an image analyser.

RESULTS

Both RBC, RBC-CM and hemolysed RBC stimulated gel contraction by fibroblasts (P < 0.001), compared to fibroblasts alone. The RBC-CM stimulated (P < 0.01) gel contraction in a time and concentration dependent manner. A similar effect was observed when supernatant from hemolysed RBC was tested. The production of fibronectin was increased (P < 0.01) in the co-culture system, compared to fibroblasts cultured alone.

CONCLUSIONS

The present study shows that RBC can interact with mesenchymal cells in vitro. The ability of RBC to modulate fibroblast-mediated contraction in vitro, might therefore be an important mechanism regulating repair processes after injury.

Prostaglandin D2 inhibits fibroblast migration

Fibroblasts play an important role in the repair and remodelling processes following injury. Prostaglandin D2 (PGD2) is a potent mediator in inflammatory processes. In this study, the effect of the PGD2 on human foetal lung fibroblasts (HFL-1) chemotaxis induced by human plasma fibronectin (HFn) was investigated using the blindwell chamber technique. PGD2 inhibited HFL-1 chemotaxis to HFn (20 microg x mL(-1)) by 20.8 +/- 3.8% (p<0.05). Checkerboard analysis of HFn-directed migration confirmed that PGD2 inhibited both chemotaxis and chemokinesis. The effect of PGD2 was concentration-dependent and the inhibitory effect diminished with time. The PGD2 receptor (DP) agonist BW245C (500 nM) had a similar effect, inhibiting chemotaxis to 39.4 +/- 6.3%. The inhibitory effects of both PGD2 and BW245C on HFL-1 chemotaxis were blocked by the DP receptor antagonist AH6809 (2 microM). The inhibitory effect of PGD2 on fibroblast chemotaxis was also blocked by the cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) inhibitor, KT5720, suggesting a DP receptor-initiated, cAMP-dependent effect mediated by PKA. Prostaglandin D2 appears to inhibit fibroblast chemotaxis, perhaps by modulating the rate of fibroblast migration. Such an effect may contribute to regulation of the wound healing response following injury in asthma patients.

Persistence of TGF-beta1 induction of increased fibroblast contractility

Fibroblast contraction of collagen gels is regarded as a model of wound contraction. Transforming growth factor (TGF)-beta added to such gels can augment contraction consistent with its suggested role as a mediator of fibrotic repair. Since fibroblasts isolated from fibrotic tissues have been suggested to express a "fibrotic phenotype," we hypothesized that TGF-beta exposure may lead to a persistent increase in fibroblasts' contractility. To evaluate this question, confluent human fetal lung fibroblasts were treated with serum-free Dulbecco modified Eagle medium (DMEM), with or without 100 pM [corrected] TGF-beta1, TGF-beta2, or TGF-beta3 for 48 h. Fibroblasts were then trypsinized and cast into gels composed of native type I collagen isolated from rat tail tendons. After 20 min for gelation, the gels were released and maintained in serum-free DMEM. TGF-beta-pretreated fibroblasts caused significantly more rapid gel contraction (52.5+/-0.6, 50.9+/-0.2, and 50.3+/-0.5% by TGF-beta1, -beta2, and -beta3 pretreated fibroblasts, respectively) than control fibroblasts (74.0+/-0.3%, P < 0.01). This effect is concentration dependent (50-200 nM), and all three isoforms had equal activity. The effect of TGF-beta1, however, persisted for only a short period of time following the removal of TGF-beta, and was lost with sequential passage. These observations suggest that the persistent increase in collagen-gel contractility, mediated by fibroblasts from fibrotic tissues, would not appear to be solely due to previous exposure of these cells to TGF-beta.

Synergistic neutrophil elastase-cytokine interaction degrades collagen in three-dimensional culture

Proteolytic degradation of extracellular matrix is thought to play an important role in many lung disorders. In the current study, human lung fibroblasts were cast into type I collagen gels and floated in medium containing elastase, cytomix (combination of tumor necrosis factor-alpha, interleukin-1beta, and interferon-gamma), or both. After 5 days, gel collagen content was determined by measuring hydroxyproline. Elastase alone did not result in collagen degradation, but in the presence of fibroblasts, elastase reduced hydroxyproline content to 75.2% (P < 0.01), whereas cytomix alone resulted in reduction of hydroxyproline content to 93% (P < 0.05). The combination of elastase and cytomix reduced hydroxyproline content to 5.2% (P < 0.01). alpha(1)-Proteinase inhibitor blocked this synergy. Gelatin zymography and Western blot revealed that matrix metalloproteinase (MMP)-1, -3, and -9 were induced by cytomix and activated in the presence of elastase. Tissue inhibitor of metalloproteinase (TIMP)-1 and -2 were also induced by cytomix but were cleaved by elastase. We conclude that a synergistic interaction between cytomix and elastase, mediated through cytokine induction of MMP production and elastase-induced activation of latent MMPs and degradation of TIMPs, can result in a dramatic augmentation of collagen degradation. These findings support the notion that interaction among inflammatory mediators secreted by mononuclear cells and neutrophils can induce tissue cells to degrade extracellular matrix. Such a mechanism may contribute to the protease-anti-protease imbalance in emphysema.

Prediction of drug clearance in humans from laboratory animals based on body surface area

The object of the study was to develop a new allometric equation for clearance from laboratory animals to humans based on body surface area (BSA allometric method). Human clearances for 30 drugs were predicted from animal data obtained from the literature. The results predicted with the method were compared with those observed. The results were also compared with values predicted with clearance versus body weight (BW simple allometric method), the product of brain weight and clearance versus body weight (Cl x BRW method) and the product of maximum life span potential and clearance versus body weight (Cl x MLP method), respectively. Good predictions were found in 21 out of 30 with the BAS allometric method. Both BSA allometric method and BW simple allometric method can give good predictions of clearance in humans for many drugs. Similarly to BW simple allometric method, Cl x BRW method and Cl x MLP method, BSA allometric method may be used to accurately predict human clearance from laboratory animal data.

Cytokine inhibition of fibroblast-induced gel contraction is mediated by PGE(2) and NO acting through separate parallel pathways

Contraction of three-dimensional collagen gels is a model of the contraction that characterizes normal healing and remodeling after injury. In the current study, we evaluated the hypothesis that a number of inflammatory factors, including tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, and interferon (IFN)-gamma, modulate this process by induction of prostaglandin (PG) E(2) and nitric oxide (NO) production and that these secondary mediators function in an autocrine or paracrine manner to modulate contraction. Human fetal lung fibroblasts (HFL) were cultured in type I collagen gels and floated in medium containing TNF-alpha, IL-1 beta, or IFN-gamma alone or in combination (cytomix). All cytokines inhibited the contraction significantly. The potency order was IL-1 beta, TNF-alpha, IFN-gamma. The cytomix was no more potent than was IL-1 beta alone. PGE(2) production was increased by TNF-alpha (5.0 versus 0.16 ng/ml, P < 0.01), IL-1 beta (5.3 versus 0.16 ng/ml, P < 0.01), and cytomix (5.9 versus 0.16 ng/ml, P < 0.01), and was completely inhibited by indomethacin. Indomethacin (P < 0.05) and L-NG-monomethyl arginine citrate (L-NMMA) (P < 0.05) alone both partially attenuated the inhibition of contraction caused by cytokines alone or by cytomix. Indomethacin and L-NMMA together attenuated inhibition more than either alone (P < 0.05). Exogenous PGE(2) and exogenous NO donors (DETA nononate and 5-amino-3-(4-morpholinyl)-1,2,3-oxadiazolium chloride) inhibited the contraction significantly. The protein kinase A inhibitor KT5270 and the protein kinase G inhibitor Rp-pCPT-cGMPS attenuated the inhibition induced by PGE(2) and NO, respectively. In summary, PGE(2) and NO appear to function in parallel as autocrine/paracrine mediators of cytokine-driven fibroblast inhibition of the contraction of collagen gels and may contribute to remodeling during repair and inflammation in lung disorders.

[Construction of CgA gene antisense transgenic mice]

In order to get CgA gene antisense DNA transgenic mouse, we constructed the CgA gene antisense DNA plasmid pCAS2C and microinjected it into the female pronucleus of fertilized mouse eggs, and transplanted them into oviduct of the foster. Every offspring of the fosters was determined by the PCR method. The positive mice had a 300 bp DNA electrophoresis band. We selected two male positive mice from 50 offspring survived of the pseudomother. Then, two positive mice crossed with normal mice respectively to reproduce offspring of F1. All offspring of F1 were determined by PCR to select positive offspring. Positive offspring of F1 carried only one allele of pCAS2C (heterozygous pCAS2C/-). Positive F1 offspring were selfcrossed, 1/4 offspring of F2 carrying two unites of one allele pCAS2C (pCAS2C/pCAS2C) are homozygous. Then, all offspring of homozygous F2 crossed with normal mice, could produce 300 bp DNA electrophoresis band by PCR. Total RNA of brain tissue of transgenic mouse was used to RT-PCR method, the 300 bp DNA product was obtained. The result indicates that the reading frame of CgA antisense DNA of pCAS2C has expressed in the transgenic mice.

Glucocorticoids and TGF-beta1 synergize in augmenting fibroblast mediated contraction of collagen gels

TGF-beta plays a central role in the initiation and progression of pulmonary fibrosis. Glucocorticoids are frequently used to treat fibrotic diseases, but beneficial effects are often modest. Both TGF-beta and glucocorticoids have been reported to increase fibroblast contraction of native collagen gels, a model of fibrotic tissue remodeling. Therefore, we sought to determine how glucocorticoids interact with TGF-beta in this system. In this study, human fetal lung fibroblasts (HFL-1) were pretreated with or without TGF-beta for 72 h before they were cast into type I collagen gels. Various concentrations of glucocorticoids (budesonide or hydrocortisone) were added at the time of casting. Gel size was then monitored at different times after gel release. The surrounding media were collected for the assay of prostaglandin E2 (PGE2) and the cell lysates were analyzed for cyclooxygenase (COX) expression by immunoblot. Glucocorticoids alone significantly enhanced fibroblast-mediated contraction of collagen gels (P < 0.01) and dose-dependently inhibited PGE2 release by HFL-1 fibroblasts. TGF-beta significantly augmented gel contraction but also induced a 30% increase in PGE2 release and increased the expression of COX-1. Glucocorticoids inhibited TGF-beta1 induced-PGE2 release, and enhanced TGF-beta augmented gel contraction without significantly affecting TGF-beta augmented COX-1 expression. Indomethacin, a COX inhibitor, increased TGF-beta augmented gel contraction but had no further effect when added together with glucocorticoids. Thus, glucocorticoids can synergize with TGF-beta in augmenting fibroblast mediated collagen gel contraction through the inhibition of PGE2 production. Such interactions between glucocorticoids and TGF-beta may account, in part, for the lack of response of fibrotic diseases to glucocorticoids.

Cigarette smoke inhibits osteogenic differentiation and proliferation of human osteoprogenitor cells in monolayer and three-dimensional collagen gel culture

Cigarette smoke is a risk factor not only for emphysema but also for other disorders characterized by deficient tissue repair, including osteoporosis. We hypothesized, therefore, that smoke might directly impair bone cell repair processes. To evaluate this, bone marrow osteoprogenitor cells were isolated from normal subjects and cultured in monolayer and in three-dimensional type I collagen gel culture. Human osteoprogenitor cells could be induced to differentiate toward osteoblast-like cells in both culture conditions by osteogenic supplements. Under both culture conditions, cigarette smoke extract (CSE) inhibited the proliferation of osteoprogenitor cells in a concentration-dependent manner. CSE also inhibited differentiation of osteoprogenitor cells toward osteoblast-like cells as assayed by alkaline phosphatase activity and calcium incorporation into cell layer. Cells in monolayer culture were more sensitive to the effect of smoke than cells in three-dimensional gel culture. Similar results were obtained with osteoblast-like cells derived from osteosarcomas. This study, therefore, demonstrates that cigarette smoke may affect bone progenitor cells directly and in this manner may contribute to the development of osteoporosis.

Co-cultured human mast cells stimulate fibroblast-mediated contraction of collagen gels

In the current study, we asked whether mast cells might modulate remodeling of extracellular matrix by affecting fibroblast-mediated contraction of three-dimensional collagen gels. Mast cells and human lung fibroblasts were co-cultured in floating type I collagen gels. The area of the gels was measured by an image analyzer. Mast cells in co-culture augmented fibroblast contractility (P < 0.001) in a time- and concentration dependent manner. The tryptase inhibitor bis(5-amidino-2-benzimidazo-lyl)methane (BABIM) were unable to block the augmented fibroblast contractility induced by co-cultured mast cells and tryptase added alone in the culture system had no effect on contractility, suggesting that other mediators besides tryptase might be involved. The amount of collagen in dissolved gels, measured as hydroxyproline, did not change after co-culture indicating that degradation of collagen may not be a major mechanism. Our findings support the hypothesis that the activity of mast cells may drive rearrangement of extracellular matrix and this and could subsequently lead to fibrosis and tissue dysfunction.