Heparin-binding EGF-like growth factor mRNA is upregulated in the peri-infarct region of the remnant kidney model: in vitro evidence suggests a regulatory role in myofibroblast transformation

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a potent fibroblast and epithelial cell mitogen that may be important in wound healing. The aim of this study was to determine its distribution and possible function in segmental renal infarction. At day 1 postinfarction, in situ hybridization showed that HB-EGF mRNA was markedly increased by tubular epithelial cells bordering the infarcted zone. At day 3, typical myofibroblasts expressing alpha-smooth muscle actin (alpha-SMA) were present in large numbers at the peri-ischemic border and, over succeeding days, were also seen within the infarcted area. Some of these cells expressed HB-EGF mRNA by in situ hybridization suggesting possible autocrine stimulation. Endothelial cells appeared to be more resistant to ischemia than tubules because some capillaries at the periphery of the infarct, surrounded by infarcted tubules, also expressed HB-EGF mRNA. The staining intensity of HB-EGF mRNA in individual tubules and endothelial cells was maximal at day 5 after infarction, although Northern blots of tissue from the peri-infarct area only showed significantly increased expression of HB-EGF mRNA at days 1 and 3, perhaps reflecting a smaller area of greater intensity of expression at day 5. Because tubular cells expressing high levels of HB-EGF mRNA were directly apposed to myofibroblasts, an attempt was made to determine whether HB-EGF contributed to upregulation of alpha-SMA by human fibroblasts. Although stimulation of the fibroblast cell line MRC-5 with transforming growth factor-beta1 (TGF-beta1) increased alpha-SMA, HB-EGF reduced expression. HB-EGF also strongly inhibited the increased expression of alpha-SMA due to TGF-beta1. Because HB-EGF is a potent fibroblast mitogen and TGF-beta is usually antiproliferative, this study suggests that HB-EGF may contribute to a local balance between fibroblast proliferation and differentiation into myofibroblasts during scarring.     

Heparin-binding epidermal growth factor-like growth factor in experimental models of membranous and minimal change nephropathy

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a recently described member of the epidermal growth factor (EGF) family. It binds to heparan sulfate proteoglycans via a cationic domain and is a potent mitogen for epithelial cells, fibroblasts and vascular smooth muscle cells. In the present study we have attempted to identify changes in quantity and distribution of HB-EGF in two models of acute glomerular epithelial cell injury, using Western blotting, immunohistochemistry and in situ hybridization. Prior to disease induction, Western blots showed some expression of HB-EGF protein within glomeruli. Within the first three days in the acute puromycin aminonucleoside (PAN) and passive Heymann nephritis (PHN) models, immunohistochemistry and in situ hybridization demonstrated an up-regulation of HB-EGF mRNA and protein in glomerular epithelial cells (GEC). In both cases, increased protein and mRNA was found prior to the onset of proteinuria and continued until day 21 post-induction, the last time point studied. Early in the course of the models, HB-EGF was localized to the cytoplasm of glomerular epithelial cells. At day 21, however, HB-EGF protein was distributed in a nodular pattern within GEC and along the glomerular basement membrane (GBM) in both models, suggesting that the secreted form might bind to the membrane. The increase in HB-EGF protein within glomeruli was confirmed by Western blots of glomerular membrane protein which, however, demonstrated a single 29 kDa species, consistent with the transmembrane form. These data are not consistent with binding of the secreted form of HB-EGF to the GBM. The transmembrane form of HB-EGF is able to signal in a juxtracrine fashion, so increased expression of HB-EGF mRNA and protein by GEC might contribute to the genesis of proteinuria through the initiation of abortive GEC mitogenesis.     

Heparin-binding EGF-like growth factor is cytoprotective for intestinal epithelial cells exposed to hypoxia

BACKGROUND: During recovery from intestinal ischemic injury, there is rapid growth of intestinal epithelia with regeneration of damaged villi. This study examines the effects of heparin-binding EGF-like growth factor (HB-EGF) on the recovery of intestinal epithelial cells exposed to hypoxia. METHODS: The cytoprotective effects of HB-EGF were analyzed by placing IEC-18 cells in an anaerobic chamber with various timed HB-EGF treatments (prehypoxia, posthypoxia, pre- and posthypoxia, and no treatment). After 10 hours of hypoxia, lactate dehydrogenase (LDH) release, actin-filament (structural) integrity, adenosine triphosphate (ATP) levels, and posthypoxia proliferative activity were evaluated. RESULTS: LDH analysis showed that HB-EGF exerted a cytoprotective effect during hypoxia. Pretreated cells had a significantly lower death rate during recovery (7.48%) compared with cells with no HB-EGF treatment (22.19%, P < .009). Confocal microscopic structural analysis of posthypoxia cells showed that F-actin structure was maintained in treated cells, whereas nontreated cells showed increased structural deterioration. ATP levels were significantly higher in the HB-EGF-treated cells compared with nontreated cells at 48 hours (P < .05). Finally, HB-EGF-treated cells had a significantly improved proliferative ability compared with nontreated cells during recovery from hypoxia (P < .05). CONCLUSIONS: HB-EGF is a mitogenic growth factor for intestinal epithelial cells. Moreover, HB-EGF appears to protect intestinal epithelial cells from hypoxia, in part via maintenance of cytoskeletal structure and ATP stores. Finally, HB-EGF-treated cells also appear to have better proliferative abilities during recovery from hypoxia.     

Polyvinyl alcohol as a defined substitute for serum in vitrification and warming solutions to cryopreserve ovine embryos at different stages of development

The purpose of this study was to assess the viability of ovine embryos after replacing fetal calf serum (FCS) with polyvinyl alcohol (PVA) in vitrification and warming solutions. Ovine embryos were obtained from superovulated Sardinian breed ewes at 4, 5, 6, and 7 days after insemination. All vitrification and warming solutions were prepared using buffered saline solution with 20% FCS (group a) or 0.1% PVA (group b). Embryos were vitrified in 20 microliters of glycerol 3.4 M + ethylene glycol 4.6 M and loaded into the centre of 0.25 ml straws between two columns of sucrose solution (0.5 M), and plunged immediately into liquid nitrogen. After being warmed in a water bath at 35 degrees C for 10 s, the vitrified embryos were moved to 0.25 M sucrose solution for 3 min. Embryos were cultured in TCM-199 after washing with 10% FCS and sheep oviductal epithelial cells up to hatching or re-expansion of the blastocoelic cavity. No significant difference in the viability rates was observed between embryos vitrified/warmed in PVA or FCS solutions. In both groups, the rate of in vitro viability was (P < 0.01) lower at the precompacted and compacted morula stages than at the expanded, hatching or hatched blastocyst stage. In both groups, early blastocysts were less viable than expanded (P < 0.01), hatching or hatched blastocyst (P < 0.05). There was no significant difference in survival rates at days 14 (79 and 76%) and 45 (63 and 59%) after transfer into sychronised recipients between vitrified expanded blastocysts of groups a and b, respectively. These results suggest that it is possible replace serum with PVA in vitrification and warming solutions without reducing in vivo and in vitro viability.     

Basic fibroblast growth factor and insulinlike growth factor I support the growth of human septal chondrocytes in a serum-free environment

OBJECTIVE: To determine if insulinlike growth factor I (IGF-I) and basic fibroblast growth factor (bFGF), individually or in combination, support the growth and viability of human septal chondrocytes in a serum-free medium (SFM) and a serum-enhanced culture medium. DESIGN: Chondrocytes were recovered from enzymatically digested human septal cartilage and were plated for monolayer culture in a newly developed medium. The medium included Dulbecco modified Eagle medium mixed 1:1 with Ham F12 medium and a supplement of known amounts of 2 growth factors-bFGF (100 ng/mL) and IGF-I (100 ng/mL)-used in combination and separately. RESULTS: The combination of IGF-I and bFGF enhanced chondrocyte growth and maintained a high degree of viability in SFM and 10% fetal calf serum. After an initial lag, the SFM, augmented with both growth factors, produced a comparable number of viable cells (4.25+/-0.31 x 10(4)) to that of the medium with 10% fetal calf serum (4.64+/-0.35 x 10(4)) by the seventh day of the experiment. Combined with the 2 growth factors, 10% fetal calf serum provided the greatest proliferation by the end of the experiment. However, the overall mean cell counts for the IGF-I- and bFGF-enhanced SFM were not statistically different. CONCLUSIONS: The combination of IGF-I and bFGF in a serum-free and a serum-supplemented environment supports the growth and viability of human septal chondrocytes in short-term culture. In an SFM, the results obtained approximate those produced in a medium enhanced with 10% fetal calf serum.     

Differential effect of ethanol on PC12 cell death

Our goal was to examine the effects of ethanol on cell death using rat pheochromocytoma (PC12) cells as a neuronal model. Withdrawal of serum for 24 hr increased the number of PC12 cells labeled with ethidium homodimer indicating an increase in cell death. Inclusion of 50 mM ethanol during the serum deprivation further increased the amount of ethidium fluorescence by 39%. Although reducing the serum concentration from the usual 15 to 4% did not alter cellular viability, a significant increase in the amount of ethidium fluorescence was observed in PC12 cells incubated for 24 hr in the presence of 4% serum and 150 mM ethanol. No change in viability was observed in cells exposed to either 150 mM ethanol in the presence of 15% serum or 50 mM ethanol in the presence of 4% serum. Inclusion of ethanol during serum deprivation increased the amount of soluble DNA found in the 15,000 x g supernatant. Similarly, using the terminal deoxynucleotidyl transferase dUTP nick-end labeling method to visualize DNA fragmentation in situ, ethanol caused a 213% increase in the number of PC12 cells labeled during serum withdrawal. Agarose gel electrophoresis of the DNA isolated from cells maintained in the absence of serum yielded the classical DNA laddering pattern of 180 to 200 bp fragments suggestive of apoptosis. Ethanol caused a concentration-dependent increase in the amount of DNA laddering in cells deprived of serum. Furthermore, ethanol significantly potentiated the DNA laddering of cells maintained in 4% serum. In contrast to the ethanol-induced increase in cell death when serum factors were reduced or withdrawn, 150 mM ethanol lowered by 34% the number of ethidium-labeled PC12 cells observed after a 30-min exposure to 2 mM H2O2. Similarly, agarose gel electrophoresis of the DNA from H2O2-treated cells did not display DNA laddering. This study demonstrates that: 1) ethanol antagonizes the trophic action of serum factors; 2) pharmacologically relevant ethanol concentrations significantly potentiate apoptosis after serum withdrawal and 3) this enhancement appears specific for apoptosis.     

Vectorial competence of Glossina tachinoides Westwood and Glossina palpalis gambiensis Vanderplank infected by Trypanosoma brucei brucei EATRO 1125]

In this work the relationship between the proliferation of bovine corneal epithelial cells and PGE2 has been studied. Our data indicate that PGE2 plays an important role in the growth of corneal epithelial cells. Actually, epithelial cells cultured on a keratocyte feeder-layer and exposed to indomethacin, a cyclooxygenase inhibitor, have shown a decrease in growth rate at drug concentrations which otherwise did not induce a reduction in the viability of the keratocytes as well as in epithelial cells in separate cultures. This effect has been reversed by an exogenous PGE2 addition to the culture media. Moreover, significant increases have been found in the growth of epithelial cells cultured in the presence of keratocytes, with basal medium and with conditioning medium after adding exogenous PGE2 at concentrations equal to or lower than 10(-6) M. Significant decreases in the dimensions of the corneal epithelial cells have been found only when PGE2 has been added to basal and to conditioning medium, suggesting that the autacoid maintains cell dimension and morphology. The appearance of keratins with high molecular weight (54 and 57 kDa) coupled with the tendency to stratification of the cells cultivated with media supplemented with PGE2, indicates that the autacoid could favour cell differentiation. The action of PGE2 on the corneal epithelial cells does not seem to be influenced by the presence of the fibroblasts and their products, since PGE2 has induced increases in cell growth and morphological variations, independent of cultural conditions and therefore also only in the presence of basal medium.     

Role of epidermal growth factor receptor and STAT-3 activation in autonomous proliferation of SUM-102PT human breast cancer cells

This report describes the isolation and characterization of a new human breast cancer cell line, SUM-102PT, obtained from a minimally invasive human breast carcinoma. SUM-102PT cells have a near diploid karyotype, and early-passage cells had minor chromosomal abnormalities including a 5, 12 and a 6, 16 reciprocal translocation. The cells were isolated and have been continually cultured in three defined media, one of which contains exogenous epidermal growth factor (EGF). SUM-102PT cells have also been carried in an EGF-free medium supplemented with progesterone. All SUM-102PT cells require EGF receptor (EGFR) activation for continuous growth, because incubation of the cells with EGFR-neutralizing antibodies or with EGFR kinase inhibitors blocks growth of these cells. Southern analysis indicates that the EGFR gene is not amplified in these cells; however, these cells express high levels of EGFR mRNA. Thus, SUM-102PT is representative of a class of human breast cancers characterized by high level EGFR expression in the absence of gene amplification. SUM-102PT cells cultured in EGF-free, progesterone-containing medium express high levels of constitutively active EGFR. Conditioned medium from SUM-102PT cells contains an EGF-like mitogen that binds to a heparin-agarose affinity matrix with high affinity. Northern analysis for various EGF family members indicates that SUM-102PT cells synthesize heparin binding (HB)-EGF mRNA. HB-EGF protein is detectable on the surface of these cells by immunohistochemistry, and SUM-102PT cells are killed by diphtheria toxin, which acts by binding to HB-EGF. Furthermore, HB-EGF antibodies partially neutralize the mitogenic activity of the conditioned medium. Thus, EGFR activation in SUM-102PT cells is mediated, at least in part, by autocrine/juxtacrine stimulation by HB-EGF. SUM-102PT cells also express constitutively active STAT-3 homodimers. Constitutively tyrosine-phosphorylated STAT-3 homodimers were also detected in another breast cancer cell line, MDA468, which has an EGFR amplification and also has constitutive EGFR activity. Thus, SUM-102PT is a new human breast cancer cell line that expresses activated EGFR as a result of an autocrine/juxtacrine interaction with HB-EGF which, in turn, results in activation of STAT-3.     

The effects of combined antifolates on inhibition of growth of murine leukemia cells cultured in vitro

PURPOSE: Long-term patency of cryopreserved vascular grafts is determined by maintained cellular and tissue viability, which implies preservation of various biochemical, smooth muscle, and endothelial functions. Therefore, it was investigated whether the presence of fetal calf serum (FCS) in the cryomedium improves the postthaw contractile and endothelial function of human arteries. METHODS: Rings from human mesenteric (HMA) and left circumflex coronary arteries (HCA) obtained from organ donors were randomized into three groups and studied either unfrozen or after storage for 3 to 6 weeks at -196 degrees C while suspended in Krebs-Henseleit solution without or with 20% FCS as the vehicles and 1.8 mol/L dimethyl sulfoxide and 0.1 mol/L sucrose as cryoprotecting agents. The samples were slowly frozen to -70 degrees C and then stored in liquid nitrogen. Before use, the tissues were thawed within 3 minutes in a 40 degrees C water bath. RESULTS: After thawing the sensitivity to various agonists and maximal responses to the endothelium-independent relaxing agent sodium nitroprusside were unchanged. However, after cryopreservation of HMA was performed without and with FCS, maximal contractile responses to noradrenaline were significantly reduced to 10.1 +/- 0.7 gm and 9.9 +/- 0.9 gm compared with 13.3 +/- 0.6 gm in unfrozen HMA (mean +/- SEM, n = 15). After cryopreservation of HCA was performed without and with FCS, maximal contractile responses to prostaglandin F2 alpha (6.9 +/- 0.4 gm in unfrozen HCA) were significantly reduced to 4.3 +/- 0.3 gm and 3.8 +/- 0.2 gm (mean +/- SEM, n = 6). In both types of arteries cryopreservation also attenuated significantly the endothelium-dependent relaxant responses to bradykinin during U46619 (10 nmol/L)-induced tone. In HMA the maximal bradykinin-induced relaxation (85% +/- 4%) was significantly diminished to 29% +/- 7% and 38% +/- 9% after cryopreservation without and with FCS (mean +/- SEM, n = 6). In HCA maximal bradykinin-induced relaxation (88% +/- 4%) was significantly diminished to 26% +/- 10% and 36% +/- 11% after cryopreservation without and with FCS (mean +/- SEM, n = 6). This result was reflected by a marked endothelial denudation in all groups of cryopreserved arteries. Neither functional nor morphologic preservation of the endothelial cell lining was significantly improved by FCS supplementation of the cryomedium. CONCLUSIONS: Cryopreservation diminished contractile and endothelium-dependent relaxant responses of human arteries. The presence of FCS in the cryomedium did not modify these changes.     

A case of advanced gastric cancer that responded to long-term administration of low-dose 5''-DFUR]

Muscle glycogen synthesis is modulated by physiologically relevant changes in cell volume. We have investigated the possible involvement of integrin-extracellular matrix interactions in this process using primary cultures of rat skeletal muscle subject to hypo- or hyper-osmotic exposure with integrin binding peptide GRGDTP to disrupt integrin actions and the inactive analogue GRGESP as control. Osmotically induced increases (77%) and decreases (34%) in glycogen synthesis (D-[14C]glucose incorporation into glycogen) were prevented by GRGDTP (but not GRGESP) without affecting glucose transport. Cytoskeletal disruption with cytochalasin D or colchicine had similar effects to GRGDTP. Osmotically induced modulation of muscle glycogen synthesis involves integrin-extracellular matrix interactions and cytoskeletal elements, possibly as components of a cell-volume 'sensing' mechanism.     

A cloned human germ cell tumor-derived cell line differentiating in culture

We have derived a clonal cell line (HGCT-1) from a lymph node metastasis of a primary testicular germ cell tumor (GCT). The tumor was negative for the embryonal carcinoma (EC) cell marker BerH2 but positive for vimentin, cytokeratin (CK) and desmin. Comparative genomic hybridization (CGH) revealed a high-level amplification at 12p that was observed in both the metastatic tumor and in the cultured HGCT-1 cells. In vitro, the phenotype of HGCT-1 cells was modulated by the culture conditions. In the presence of 10% fetal calf serum (FCS), the majority of HGCT-1 cells lacked CK and desmin. If cultured in 0.5% FCS, HGCT-1 cells acquired a uniform co-expression of vimentin, CK and desmin. Upon treatment with retinoic acid (RA), HGCT-1 cells lost the expression of desmin, but exhibited abundant CK filaments. Simultaneously, they started to express desmoplakin, form desmosomes and flatten on the culture substratum. The RA-induced changes were irreversible, whereas those following the culture in 0.5% FCS were at least partially reversible. When xenografted into an immunosuppressed rat, HGCT-1 cells formed a tumor consisting of epithelial- and mesenchymal-like structures. HGCT-1 cells thus represent a pluripotential cell system with a capacity for reversible phenotypic modulation and for irreversible differentiation into epithelial-type cells. The behavior of this novel cell line, distinct from established EC cell models, suggests a complex regulation of GCT cell differentiation.     

Cell cycle-dependent tumor necrosis factor apoptosis

To determine if tumor necrosis factor (TNF)-mediated apoptosis affects cells at defined stages of the cell cycle, WEHI-164/2F (WEHI) cells were synchronized at G0-G1 after 3-day cultures in medium containing RPMI 1640 and 0.5% FCS (RPMI-0.5% FCS). The arrested WEHI cells (60-75% in G0-G1) showed increased sensitivity to TNF killing, measured as 48-h 3-(5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assays, and 15-h apoptosis by propidium iodide staining and flow cytometry analysis. The TNF killing kinetics of G0-G1-arrested cells was similar to controls, and TNF did not accelerate or retard cell cycle progression of the arrested cells after feeding with fresh RPMI-0.5% FCS. However, TNF inhibited WEHI DNA synthesis as early as 1 h after treatment, and inhibition was proportionate to sensitivity to TNF-induced apoptosis. WEHI cells treated with TNF showed a higher percentage of cells in S phase with concomitant decrease in G0-G1 and G2-M. When cultured for 3-18 h in fresh RPMI-0.5% FCS to allow progression of the G0-G1-arrested cells toward the G1-S boundary, WEHI cells became more sensitive to TNF killing, especially at the 3-9 h time points. Moreover, TNF did not degrade [125I]5-iodo-2'-deoxyuridine-labeled WEHI DNA if the labeled cells were precultured for 9 h in fresh RPMI-0.5% FCS to allow them to pass S phase before the addition of TNF. These results show that TNF-induced apoptosis of WEHI cells is connected to cell cycle events; WEHI targets receive the TNF cytotoxic signal mainly at the G1-S boundary and begin to die by apoptosis as they exit from S phase.     

Concentrations of specific epithelial growth factors in the urine of interstitial cystitis patients and controls

PURPOSE: Interstitial cystitis (IC) is a chronic bladder disease for which the etiology is unknown. Because the bladder epithelium is often abnormal in IC, we determined whether the levels of specific urine growth factors postulated to be important for bladder epithelial proliferation are altered in IC. MATERIALS AND METHODS: ELISAs were used to determine levels of epidermal growth factor (EGF), insulin-like growth factor 1 (IGF1), insulin-like growth factor binding protein 3 (IGFBP3), and heparin binding epidermal growth factor-like growth factor (HB-EGF) in urine specimens from women with IC, asymptomatic women without bladder disease, and women with bacterial cystitis. RESULTS: Urine HB-EGF levels were specifically and significantly decreased in IC patients as compared to asymptomatic controls or patients with bacterial cystitis, whether expressed as concentration (amount per volume of urine) or the amount relative to urine creatinine in each specimen. In contrast, urine EGF, IGF1, and IGFBP3 levels were all significantly elevated in IC patients compared to asymptomatic controls. Further, the amounts of urine EGF and IGF1 were also elevated in IC patients as compared to patients with bacterial cystitis, and urine IGFBP3 levels were significantly elevated when expressed per milligram of urine creatinine. CONCLUSIONS: These findings indicate that complex changes in the levels of urine epithelial cell growth factors (EGF, IGF1, and HB-EGF) and a growth factor binding protein (IGFBP3) are associated with IC. While EGF, IGF1, and IGFBP3 levels are either the same or increased in the urine of IC patients as compared to patients with bacterial cystitis or asymptomatic controls, HB-EGF levels are significantly decreased in the urine of IC patients. Understanding the reasons for these changes may lead to understanding the pathogenesis of this disorder.     

Hepatocyte growth factor releases epithelial and endothelial cells from growth arrest induced by transforming growth factor-beta1

Human lung fibroblasts and Mv1Lu mink lung epithelial cells were used as a model to study the role of extracellular matrix in epithelial-mesenchymal interactions. Extracellular matrices of fibroblasts were found to contain growth promoting activity that reduced the sensitivity of Mv1Lu cells to the growth inhibitory effects of transforming growth factor-beta (TGF-beta). The majority of the activity was identified as hepatocyte growth factor/scatter factor (HGF) by inhibition with specific antibodies and by reconstitution of the effect by recombinant HGF. HGF induced cell proliferation when contact-inhibited Mv1Lu cells were trypsinized and plated in the presence of TGF-beta1. The effect was valid also in assays where Madin-Darby canine kidney epithelial cells or bovine capillary endothelial cells were used. The multiplication of chronically TGF-beta1 inhibited Mv1Lu cells was also induced by HGF. In addition, HGF induced anchorage independent growth of Mv1Lu cells that was refractory to TGF-beta1 growth inhibition. Immunoprecipitation analysis indicated that HGF prevented the suppression of Cdk4 and Cdk2, but not the induction of p21, by TGF-beta1. Since both TGF-beta1 and HGF require proteolysis for activation, the results imply that proteolytic activity of epithelial and endothelial cells directs their responses to signals from mesenchymal-type extracellular matrices, and that during development, matrix-bound growth and invasion promoting and suppressing factors are activated in a coordinated manner.     

Total knee arthroplasty kinematics. Computer simulation and intraoperative evaluation

Early diagnosis of rejection is a pivotal problem in renal transplantation. Recent advances in urinary cell analysis using flow cytometry are still burdened with difficulties concerning urine lymphocyte (UL) isolation. The analysis of lymphocytes washed out with the urine from the kidney transplant offers a tool to monitor noninvasively the intragraft immune response. However, the demand for optimal isolation of UL with high viability and good separation of other cell types has not, as yet, been met. The present study was undertaken to evaluate the optimal conditions for harvesting UL in order to perform adequate UL analysis by flow cytometry. We found that UL viability is mainly dependent on the time of urine harvesting. Low UL viability was caused by high urine osmolality due to high concentrations of urea and glucose. In contrast, high protein concentrations protected UL viability. Hence, the following algorithm of adequate UL isolation for flow cytometric analysis was established: (1) Collection of morning urine directly onto foetal calf serum (FCS: 30% v/v): (2) UL isolation within 2 h; (3) Erythrocyte lysis with subsequent two-step density gradient isolation of UL from residual erythrocytes, granulocytes (Ficoll-Isopaque, 1.077 g/cm3) and from uroepithelial cells (30% methylglucamine 3,5-diacetomido-2,4,6-triiodobenzoicum, 1.085 g/cmn3); (4) Flow cytometric analysis of UL using the 'live gate' setting in the area of blood lymphocyte cluster. Adequate UL isolation and special settings of the flow cytometer may provide a useful tool for early diagnosis and the noninvasive monitoring of renal transplant rejection.     

Expression of sialyltransferase is not required for interaction of Neisseria gonorrhoeae with human epithelial cells and human neutrophils

Sialyltransferase (Stase) in Neisseria gonorrhoeae organisms (gonococci [GC]) transfers sialic acid (N-acetylneuraminic acid [NANA]) from cytidine 5'-monophospho-N-acetylneuraminic acid (CMP-NANA) mainly to the terminal galactose (Gal) residue in the Gal beta-1,4 N-acetylglucosamine (Gal-GlcNAc)-R lipooligosaccharide (LOS) structure. Sialylated GC resist killing by normal human serum, sometimes show reduced invasion of epithelial cells, and have reduced adhesion to and stimulation of human neutrophils. We questioned whether Stase itself modulates the interactions of GC with human epithelial cells and neutrophils in the absence of exogenous CMP-NANA. To that end, we treated strain F62 with ethyl methanesulfonate and grew approximately 175,000 colonies on CMP-NANA plates, and screened them with monoclonal antibody 1B2-1B7 (MAb 1B2). MAb 1B2 is specific for Gal-GlcNAc and reacts only with asialylated GC. We isolated 13 MAb 1B2-reactive mutants, including five null mutants, that had Stase activities ranging from barely detectable to fivefold less than that of wild-type (WT) F62. The LOS phenotype of Stase null mutants was identical to that of WT F62, yet the mutants could not sialylate their LOS when grown with CMP-NANA. The Stase null phenotype was rescuable to Stase+ by transformation with chromosomal DNA from WT F62. Stase null mutants remained serum sensitive even when grown with CMP-NANA. One Stase null mutant, ST94A, adhered to and invaded the human cervical epithelial cell line ME-180 at levels indistinguishable from that of WT F62 in the absence of CMP-NANA. In human neutrophil studies, ST94A stimulated the oxidative burst in and adhered to human neutrophils at levels similar to those of WT F62. ST94A and WT F62 were also phagocytically killed by neutrophils at similar levels. These results indicate that expression of Stase activity is not required for interaction of GC with human cells.     

In vitro cultivation of Trypanosoma acomys: production of insect stages and bloodstream forms

When Trypanosoma acomys bloodstream forms were cultivated at 37 degrees C in Schneider's Drosophila medium supplemented with 20% (v/v) heat-inactivated foetal calf serum (FCS), with Microtus agrestis embryonic fibroblasts in RPMI 1640 medium supplemented with 20% FCS or in Baltz's medium supplemented with 10% FCS, the parasites transformed and largely remained as epimastigotes. Epimastigotes were also usually the commonest stage observed when the parasites were co-cultivated with a mosquito cell line at 27 degrees C. However, if these cultures were initiated with the supernatant suspensions from fibroblast cultures that had been cryopreserved, trypomastigotes, including bloodstream-like forms, were the predominant stage for the first 4 days of culture. It is suggested that the glycerol supplement or the temperature changes stimulated this unusual morphogenesis. At 27 degrees C, T. acomys was incapable of multiplying and died when cultured in fresh Schneider's Drosophila medium supplemented with 20% FCS, but co-cultivation with the mosquito cell lines or cultivation in cell-free supernatants from 1-week-old mosquito cell cultures was successful at this temperature; most of the parasites multiplied as epimastigotes.     

The Epstein-Barr virus latent membrane protein 1 induces expression of the epidermal growth factor receptor

The Epstein-Barr virus (EBV)-encoded LMP1 protein is an important component of the process of transformation by EBV. LMP1 is essential for transformation of B lymphocytes, most likely because of its profound effects on cellular gene expression. Although LMP1 is expressed in the majority of nasopharyngeal carcinoma (NPC) tumors, the effect of LMP1 on cellular gene expression and its contribution to the development of malignancy in epithelial cells is largely unknown. In this study the effects of LMP1 on the expression and tyrosine kinase activity of the epidermal growth factor receptor (EGFR) were investigated in C33A human epithelial cells. Stable or transient expression of LMP1 in C33A cells increased expression of the EGFR at both the protein and mRNA levels. In contrast, expression of the EGFR was not induced by LMP1 in EBV-infected B lymphocytes. Stimulation of LMP1-expressing C33A cells with epidermal growth factor (EGF) caused rapid tyrosine phosphorylation of the EGFR (pp170) as well as several other proteins, including pp120, pp85, pp75, and pp55, indicating that the EGFR induced by LMP1 is functional. LMP1 also induced expression of the A20 gene in C33A epithelial cells. In C33A cells, LMP1 expression increased the proliferative response to EGF, as LMP1-expressing C33A cells continued to increase in number when plated in serum-free media supplemented with EGF, while the neo control cells exhibited very low levels of viability and did not proliferate. Immunoblot analysis of protein extracts from nude mouse-passaged NPC tumors also demonstrated that the EGFR is overexpressed in primary NPC tumors as well as those passaged in nude mice. This study suggests that the alteration in the growth patterns of C33A cells expressing LMP1 is a result of increased proliferative signals due to enhanced EGFR expression, as well as protection from cell death due to LMP1-induced A20 expression. The induction of EGFR and A20 by LMP1 may be an important component of EBV infection in epithelial cells and could contribute to the development of epithelial malignancies such as NPC.     

Characterization of the embryotrophic activity of exogenous protein-free oviduct-conditioned medium used in culture of cattle embryos

Bovine zygotes, obtained after in vitro maturation and fertilization of oocytes from slaughtered cow ovaries, were cultured in droplets of nonconditioned or conditioned medium on bovine oviduct cell monolayers. The media tested were Medium 199 alone and Medium 199 supplemented with 10% fetal calf serum (FCS). Oviduct conditioning increased both early cleavage and development to blastocysts. Only the effect on early cleavage was mimicked by FCS. The blastocysts obtained in serum-free conditioned medium (SFCM) appeared morphologically normal and had the same cell number as those produced in conditioned medium containing serum. Their hatching rates did not differ. Transfer of 16 blastocysts developed in SFCM to 16 synchronized recipients resulted in five pregnancies (31%), indicating good embryonal viability. Boiling of SFCM resulted in a total loss of activity, while heating at 56 degrees C for 30 min had no deleterious effect. A 10-kDa ultrafiltration of SFCM removed the blastocyst development-supporting activity from the filtrate but not the early cleavage-favoring activity. This allows us to conclude that at least two different factors are present in SFCM: one of low molecular mass (< approximately 10 kDa), needed to obtain the 5-8 cell stage and mimicked by FCS, and another of higher molecular mass allowing embryos to develop from the 8-cell to blastocyst stage.