Expression of functional CXCR4 chemokine receptors on human colonic epithelial cells.

In addition to their role as regulators of leukocyte migration and activation, chemokines and their receptors also function in angiogenesis, growth regulation, and HIV-1 pathogenesis--effects that involve the action of chemokines on nonhematopoietic cells. To determine whether chemokine receptors are expressed in human colonic epithelium, HT-29 cells were examined by RT-PCR for the expression of the chemokine receptors for lymphotactin, fractalkine, CCR1-10, and CXCR1-5. The only receptor consistently detected was CXCR4 (fusin/LESTR), although HT-29 cells did not express mRNA for its ligand, stromal cell-derived factor (SDF-1alpha). Flow cytometric analysis with anti-CXCR4 antibody indicated that the CXCR4 protein was expressed on the surface of roughly half of HT-29 cells. CXCR4 was also expressed in colonic epithelial cells in vivo as shown by immunohistochemistry on biopsies from normal and inflamed human colonic mucosa. The mRNA for SDF-1alpha and other CC and CXC chemokines was present in normal colonic biopsies. The CXCR4 receptor in HT-29 cells was functionally coupled, as demonstrated by the elevation in [Ca2+]i, which occurred in response to 25 nM SDF-1alpha and by the SDF-1alpha-induced upregulation of ICAM-1 mRNA. Sodium butyrate downregulated CXCR4 expression and induced differentiation of HT-29 cells, suggesting a role for CXCR4 in maintenance and renewal of the colonic epithelium. This receptor, which also serves as a coreceptor for HIV, may mediate viral infection of colonic epithelial cells.

Normal and neoplastic human plasma cells express bcl-2 antigen.

The bcl-2 (B-cell leukaemia/lymphoma 2) proto-oncogene is associated with the 14;18 translocation in follicular lymphoma juxtaposing bcl-2 with the immunoglobulin heavy chain region. bcl-2 has been cloned and sequenced and a monoclonal antibody to amino acids 41 to 54 of the bcl-2 protein has been raised. The expression of bcl-2 in follicular lymphoma has been demonstrated by immunohistological staining and also in normal lymphocytes. The presence of the bcl-2 onco-protein has been demonstrated by immunofluorescence using conventional and confocal microscopy in normal and malignant plasma cells from myeloma patients and myeloma cell lines. Plasma cells from 8/8 normal donors were positive, although the proportion of positive cells and the intensity of staining varied. Eight of 10 patients with myeloma or plasma cell leukaemia had positive plasma cells, and 6/11 plasma cell lines and one lymphoma cell line also expressed the onco-protein. bcl-2 expression is a feature of normal plasma cells and data from the cell lines confirm that expression is not dependent on the presence of the 14;18 translocation.

Endothelium-dependent relaxation of rat aorta and main pulmonary artery by the phytoestrogens genistein and daidzein.

OBJECTIVE: The dietary phytoestrogens genistein and daidzein have been shown to relax agonist-preconstricted arteries in vitro; the mechanisms of relaxation remain incompletely understood. This study aimed to determine whether the relaxation of phenylephrine (PE)-constricted rat aorta and main pulmonary artery by genistein and daidzein was endothelium-dependent. METHODS: Effects of endothelial-denudation, and pretreatment with with 100 microM L-N(G)-nitroarginine methyl ester (L-NAME) and/or 10 microM indomethacin on relaxation of PE (1 microM)-preconstricted contractures by genistein (1-100 microM) and daidzein (3-100 microM) were assessed by measuring isometric force development by rat arterial rings. The effect of L-NAME on relaxation to 17beta-estradiol (10 microM) was also measured in aorta. RESULTS AND CONCLUSIONS: Genistein and daidzein caused concentration-dependent relaxation of aorta rings preconstricted with PE (1 microM). The IC50 values were 5.7 microM (n=8, 95% confidence limits 4.3-7.7 microM) and 36.7 microM (n=12, 95% confidence limits 25.7-44.1 microM), respectively. Removal of the endothelium and pretreatment with L-NAME (100 microM) significantly inhibited relaxation at 3, 10 and 30 microM genistein and 10 and 30 microM daidzein. The contracture evoked in rat aorta by depolarization with 75 mM K+ solution was similarly relaxed by genistein in a partially endothelium-dependent manner. 17Beta-estradiol (10 microM) caused a 48.7+/-5.0% (n=11) relaxation of the PE contracture, which was significantly reduced to 25.1+/-5.3% (n=7) by L-NAME. Relaxations brought about by 17beta-estradiol, genistein, and daidzein were not significantly affected by the genomic estrogen receptor antagonist ICI 182,780 (10 microM). Similar endothelium-dependent effects of genistein were observed in the main pulmonary artery. The results show that the relaxation of these rat arteries by concentrations of genistein and daidzein which overlap those present in human plasma after ingestion of soybean-containing meals is largely endothelium dependent.

Modified low density lipoprotein and cytokines mediate monocyte adhesion to smooth muscle cells.

Monocyte adhesion to the arterial wall is a key event in the atherosclerotic process. We studied the interactions between human coronary arterial intimal smooth muscle cells (SMCs) and monocytes by examining (i) whether SMCs mediate monocyte adhesion when stimulated by oxidatively modified low density lipoprotein (LDL) or by the cytokines TNF alpha and IL-1, and (ii) the role of the adhesion molecules VCAM-1 and ICAM-1 (vascular cell and intercellular adhesion molecule, respectively) in this process. Preincubation of SMCs with both TNF alpha and IL-1 caused a significant 2-fold increase in VCAM-1 and ICAM-1 expression and a more than 9-fold increase in monocyte adhesion. The latter was significantly inhibited (by 1/3) by neutralising antibodies to VCAM-1 and ICAM-1. Modified LDL also induced a significant 3-fold increase in monocyte adhesion to SMCs, but did not induce VCAM-1 or ICAM-1 expression, nor was this adhesion inhibited by neutralising antibodies to VCAM-1 or ICAM-1. Oxidatively modified LDL, like the proinflammatory cytokines TNF alpha and IL-1, has the ability to enhance monocyte adhesion to human SMCs in vitro. LDL-induced monocyte adhesion to SMCs is distinct from that induced by TNF alpha and IL-1 in its lack of dependence on the classical adhesion pathways involving smooth muscle VCAM-1 and ICAM-1. SMCs are identified as a new cell population which may play an active role in recruiting monocytes to the arterial intima and atherosclerotic plaque.

Gonadal regulation of pituitary hormone mRNA levels in male rats.

The control of anterior pituitary hormone gene expression by testosterone in male rat pituitaries in vivo was investigated using dot-blot mRNA-cDNA hybridization assays. Common alpha subunit mRNA levels doubled by 2 days after orchidectomy and rose progressively to reach plateau levels three to four times intact control values by 2 weeks. LH-beta mRNA increased significantly (congruent to 50%) within 12 h, and thereafter progressively to seven times intact control values by 3 weeks after orchidectomy. The changes in alpha mRNA were likely to have occurred in gonadotrophs and not thyrotrophs, since TSH-beta mRNA levels were unaltered by orchidectomy. LH subunit mRNA changes were accompanied by an initial (1-4 days) decrease in pituitary LH content; thereafter, pituitary LH increased in parallel with and by a similar magnitude to the LH-beta mRNA. Serum LH rises occurred before significant increases in LH subunit mRNA after orchidectomy. The lack of temporal correlation between mRNA levels and serum and pituitary LH in the early stages after removal of testosterone feedback contrasts with the good correlation when a new steady state was achieved after 3-4 weeks, and indicates differing kinetics for changes in these aspects of gonadotroph function. An inhibitory effect of testosterone on LH subunit gene expression was confirmed by prevention of the rise in alpha and LH-beta mRNAs when treatment commenced immediately after castration. However, pituitary LH content and serum LH levels were reduced relative to control values, suggesting additional inhibitory actions of testosterone on translational and post-translational events in gonadotrophs.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of LH subunit mRNA levels by gonadal hormones in female rats.

To determine the physiological role of the ovaries in regulation of LH subunit gene expression, levels of cytoplasmic mRNA were measured in a cDNA-RNA dot-blot hybridization assay. An increase (twofold) in alpha mRNA was first detected 8 days after ovariectomy and then remained stable for 4 weeks. In contrast, LH-beta mRNA increased by 60-79% within 12 h of removing the ovaries and then rose progressively to six times the intact values at 3 and 4 weeks. Increases in LH-beta mRNA were always greater than those of alpha mRNA. Oestradiol, and oestradiol plus progesterone, but not progesterone alone, prevented the rise in alpha and LH-beta mRNA 10 days after ovariectomy. Three days after ovariectomy, alpha mRNA, but not LH-beta mRNA, was suppressed to below intact control values by oestradiol and oestradiol plus progesterone, indicating greater sensitivity of alpha mRNA to oestradiol inhibition at this stage. A single injection of oestradiol (1 microgram s.c.) to rats ovariectomized 14 days previously transiently suppressed alpha and LH-beta mRNA levels and serum LH concentrations in parallel for 1-8 h, after which high preinjection values were restored. However, pituitary LH content remained suppressed after LH mRNA levels had returned to the control values of ovariectomized rats. In most instances there was a qualitative positive correlation between changes in alpha and LH-beta mRNA, pituitary LH content and serum LH concentrations. LH content reflected LH-beta mRNA changes more closely than those of alpha mRNA. However, in oestradiol-treated rats ovariectomized 10 days previously, LH content remained increased despite normalization of the LH-beta and alpha mRNA levels, suggesting differential sensitivity to oestradiol of the gene expression and translational processes. Thus divergence of pre- and post-translational regulation of LH biosynthesis was demonstrated. These results imply an important physiological role for female sex hormones in the control of LH gene expression and LH biosynthesis. Prolactin mRNA fell by 30-50% for the first 2 weeks after ovariectomy, but by 3 and 4 weeks values were similar to those of intact controls. Serum and pituitary prolactin levels were reduced by 50% or more at all time-points, despite normalization of mRNA. Treatment of ovariectomized rats for 10 days with oestradiol and progesterone, either alone or combined, reversed the fall in prolactin mRNA and serum and pituitary prolactin levels. These changes in prolactin gene expression and synthesis were opposite to those of LH subunits in response to the same in-vivo hormone manipulations.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of the pretranslational regulation of FSH synthesis by gonadal steroids in rats and mice.

There are significant differences between rats and mice in the gonadal regulation of several aspects of gonadotroph function. To investigate whether these extend to the pretranslational regulation of FSH synthesis by gonadal steroids, we have measured FSH-beta mRNA levels following gonadectomy and sex-steroid replacement and have related these to serum and pituitary FSH as a reflection of overall hormone synthesis. In ovariectomized rats, FSH-beta mRNA levels increased by 8 h, decreased, and then rose progressively over the next 28 days. A similar pattern of response was observed in orchidectomized rats. In mice, there were progressive increases in FSH-beta mRNA levels in both males and females following gonadectomy, without evidence of the early peaks observed in rats. In both species, the change in FSH-beta mRNA levels after gonadectomy was greater in females than in males. These changes in FSH-beta mRNA following gonadectomy were paralleled by changes in the serum FSH concentration. In ovariectomized female rats and mice, pituitary FSH stores increased by 8 h and 3 days respectively, whereas in male rats, pituitary FSH content did not rise until 10 days after orchidectomy. The most striking species difference was the marked and prolonged reduction of pituitary FSH after orchidectomy of mice. Treatment of rats and mice from the time of ovariectomy, with a dose of oestradiol that prevents increases in serum LH, only partially attenuated the rises in FSH-beta mRNA and serum FSH and did not prevent the increase in pituitary FSH content. Treatment of intact or orchidectomized rats with testosterone suppressed FSH-beta mRNA levels to 50% below intact control values without affecting pituitary FSH content.(ABSTRACT TRUNCATED AT 250 WORDS)

Cyclosporine and cremaphor modulate von Willebrand factor release from cultured human endothelial cells.

Cyclosporine has been associated with microangiopathic hemolysis (MAHA) and other thrombotic complications of bone marrow and renal transplantation. MAHA is characterized by intravascular platelet aggregation, which, in some situations, is thought to be mediated by hyperactive high molecular weight von Willebrand factor (vWF). We have hypothesized that transplant-related MAHA may be caused by CsA-mediated release of von Willebrand factor from endothelial cells. This hypothesis was tested by studying vWF release from human umbilical vein endothelial cells primed with either CsA or cremophor EL. CsA and cremophor alone did not increase vWF release until toxic concentrations were reached (50-100 micrograms/ml). However, at therapeutic concentrations (0.1-5 micrograms/ml) vWF release by cells stimulated with thrombin, histamine, PMA, and the calcium ionophore A23187 was enhanced by both CsA and cremophor in a concentration-dependent manner. In single isolated endothelial cells, the thrombin-induced increase in cytosolic free calcium was enhanced by both CsA and cremophor. Preincubation for 24 hr with CsA but not cremophor suppressed vWF release after thrombin stimulation. These observations were mirrored by a concentration-dependent suppression of [3H]thymidine uptake by CsA. We conclude that CsA vehicle, cremophor, enhances stimulated vWF release in vitro, probably by processes dependent upon increased cytosolic free calcium. This suggests a possible mechanism for thrombotic transplant complications.

Cyclic adenosine nucleotides and growth hormone-releasing factor increase cytosolic growth hormone messenger RNA levels in cultured rat pituitary cells.

The cellular mechanisms involved in GH biosynthesis have been investigated by the measurement of steady-state levels of cytosolic GH messenger RNA (mRNA) in primary cultures of rat pituitary cells using an RNA-complementary DNA (cDNA) hybridization assay. Growth hormone mRNA-cDNA hybridization increased in a linear manner with increasing cytosol concentration. Cellular GH mRNA levels rose by an average of 2.4-fold (range, 1.6-3.3; n = five experiments) after exposure to GH-releasing factor (GRF(1-40); 10 nmol/l) for 3 days. Treatment with GRF increased the release of GH into the culture medium, and depleted the cellular GH content by 40%. Total GH (in the medium plus cells) after GRF treatment increased by between 1.5- and 3.8-fold, a magnitude similar to the increase in GH mRNA levels. Treatment of cells with dibutyryl adenosine 3':5'-cyclic monophosphate (1 mmol/l) or forskolin (5 mumol/l) increased the levels of cytosolic GH mRNA by between 1.6- and 4.7-fold. These agents increased GH release into the medium, depleted cellular GH content and increased total GH in the system to the same extent as GRF (10 nmol/l). These data demonstrate that cyclic adenosine nucleotides may mediate the GRF induction of GH gene transcription. In addition, we have shown that increases in the levels of cellular GH mRNA are reflected by increased GH biosynthesis, suggesting that the regulation of hormone gene transcription is one cellular site for the control of hormone biosynthesis and, ultimately, hormone available for release.

Castration increases luteinizing hormone subunit messenger RNA levels in male rat pituitaries.

The effect of castration on pituitary common alpha and LH-beta subunit mRNA levels was examined in adult male rats in a dot-blot hybridization assay using cytosolic mRNA and 32P labelled plasmids containing cDNA encoding sequences of the subunits. Orchidectomy increased alpha subunit mRNA levels threefold by day 4 with no further rise at 2 months. The LH-beta subunit mRNA levels increased by threefold at 2 months. Serum LH levels increased by up to fortyfold (2 months). Pituitary LH content increased by fourfold at 2 months, though was reduced at 4 days after castration. These results suggest that transcription of the alpha and LH-beta genes are similarly regulated after castration. However the greater magnitude of serum LH increase after castration than that of both LH subunit mRNA levels and the bidirectional changes in pituitary LH content implies additional translational/post-translational control of gonadotrophin biosynthesis by gonadal hormones.

Dissociation between pituitary GnRH binding sites and LH response to GnRH in vitro.

Experiments were performed to study gonadotroph responsiveness to gonadotrophin releasing hormone (GnRH) in vitro in dispersed pituitary cells from ovariectomised rats and mice when GnRH binding sites were increased or reduced, respectively. Maximal/basal LH release after GnRH treatment of intact female rat pituitary cells was 4.7 to 9.7-fold (range n = 3 expts.) compared to 3.4 to 5.0-fold for cells from ovariectomised rat donors. Both basal and maximal GnRH-stimulated LH release from ovariectomised (OVX) rat pituitary cells were 1.5 to 3-fold greater than from intact rat cells, which corresponded to increased LH content of the cells. There was no significant change in the GnRH ED50 concentration (intact = 2.3 +/- 0.03 X 10(-10) M; OVX = 3.3 +/- 0.08 X 10(-10) M (mean +/- SEM, n = 3 expts.)), despite a 57-88% increase in GnRH binding sites in ovariectomised rat pituitary cells. Basal and maximal LH release from ovariectomised mouse pituitary cells was 1.5 to 3-fold greater than that from intact mouse pituitary cells. There was no change in the GnRH ED50 concentration (intact = 4.3 +/- 2.3 X 10(-9) M; OVX = 3.4 +/- 0.9 X 10(-9) M (mean +/- SEM, n = 3 expts.)), even though GnRH binding sites were reduced by 40-73% in the cells from ovariectomised mice. These data indicate that changes in GnRH binding sites of the magnitude observed after ovariectomy play no part in the regulation of gonadotroph responsiveness to GnRH, which is determined by changes in post-receptor events, one of which is an increase in cellular LH.

Extent of oxidative modification of low density lipoprotein determines the degree of cytotoxicity to human coronary artery cells.

OBJECTIVE: To assess whether the extent of LDL oxidation influences its cytotoxic effects, thus contributing to its atherogenic potential. DESIGN AND SETTING: The effects of native and modified LDL on cultured human coronary artery smooth muscle cells (SMC) and endothelial cells (ECs) were investigated. MAIN OUTCOME MEASURES: Four indices of cytotoxicity were studied: (i) chromium-51 release; (ii) 5-bromo-2'-deoxyuridine (BrDUrd) uptake; (iii) morphological appearance; and (iv) EC migration. RESULTS: (i) Minimally modified (mm) LDL (400 micrograms/ml) causes significant 51Cr release; the cytotoxic effect was significantly greater for copper oxidised (ox) LDL (400 micrograms/ml). Native LDL had no effect. (ii) BrDUrd uptake studies showed significant inhibition of cell proliferation by 100 micrograms/ml of oxLDL and to a lesser extent by mmLDL; native LDL had no effect. (iii) Morphological appearance was not altered by native LDL. Changes in cell morphology were induced by mmLDL (400 micrograms/ml), and were more pronounced with oxLDL in concentrations of > or = 200 micrograms/ml. (iv) EC migration was significantly inhibited by oxLDL (100 micrograms/ml), but not by native or mmLDL. CONCLUSION: The extent of oxidation of LDL determined its cytotoxicity to coronary artery cells. Native LDL had no cytotoxic effect. In contrast, oxLDL and to a lesser extent mmLDL caused cytotoxicity at concentrations to which cells in vivo might be exposed. This may contribute to the atherogenicity of modified LDL by enhancing cellular injury and inflammation, and by inhibiting re-endothelialisation of areas of coronary artery damaged during the atherogenic process.

From Beijing to Istanbul: the Super Coalition on Women, Homes and Community.

PIP: In 1994, the Super Coalition on Women, Homes, and Community was formed from four worldwide networks so that women working on community development could be involved in Habitat II planning and could incorporate human settlement issues into the Fourth World Conference on Women (WCW) and it attendant NGO (nongovernmental organization) Forum. The Super Coalition paved the way for grassroots women to contribute ideas to the Preparatory Committee for Habitat II. When the women discovered that many of the gains achieved at the WCW were not reflected in the Habitat agenda, they drafted amendments that were later discussed by official bodies. The women also lobbied delegations and governmental groups on gender issues and found that many of their concerns were included in bracketed paragraphs for further consideration during Habitat II. Another success occurred when the Secretary-General of Habitat II appointed many women to the newly-created Huairou Commission, which will offer advice on gender issues and highlight women's concerns during Habitat II.^ieng

Propionate-induced relaxation in rat mesenteric arteries: a role for endothelium-derived hyperpolarising factor.

Short chain fatty acids, including propionate, are generated in the caecum and large intestine, and when absorbed may elicit localised increases in intestinal blood flow. We sought to assess the mechanism by which propionate caused vasorelaxation. Propionate-mediated relaxation of noradrenaline-preconstricted rat mesenteric small arteries (RMSAs, i.d. 200-300 microm) was studied using small vessel myography. Propionate (1-30 mM) produced a concentration-dependent relaxation. Relaxation induced by 10 mM propionate (the approximate EC50) was almost abolished by endothelial denudation, although a marked relaxation to a very high concentration of propionate (50 mM) persisted in the absence of the endothelium. In endothelium-intact RMSAs, relaxation to 10 mM propionate was almost abolished by elevating [K+]o to 25 mM, but was unaffected by 100 microM N(omega)-nitro-L-arginine methyl ester (L-NAME) (68 +/- 4 vs. 66 +/- 3% in controls, n = 35), or by 1 microM indomethacin (60 +/- 4 vs. 61 +/- 7 % in controls, n = 15). In the presence of L-NAME, relaxation to 10 mM propionate was significantly and markedly (i.e. > 50 %) inhibited by 50 microM Ba2+ and by the combination of 100 nM charybdotoxin and 100 nM apamin. A similar effect on propionate-mediated relaxation was also exerted by 100 microM ouabain, and by the combination of 50 microM barium with ouabain. Relaxation was also significantly and markedly inhibited by pre-treatment of RMSAs with 100 nM thapsigargin or 10 microM cyclopiazonic acid (CPA). The results demonstrate that 10 mM propionate relaxes RMSAs via endothelium-derived hyperpolarising factor (EDHF). The observation that relaxation by propionate is inhibited by thapsigargin and CPA suggests that this action of propionate involves the release of endothelial cell Ca2+ stores.

Variations in the distribution of motor end-plates in the avian pectoralis.

Most avian muscles consist of serially arranged, overlapping fibers that do not extend the length of the muscle. This condition appears to be plesiomorphic with respect to diapsid reptiles. The presence of this serialfibered architecture is evidenced by bands of stained motor end-plates (meps) perpendicular to the columns of fibers and dividing each column into a series of "segments." The avian pectoralis was chosen for a study of variation in the distribution of meps within a single muscle. We report the interspecific variation for 158 specimens in 63 species. We also use additional specimens to examine intraspecific variation. Setting aside hummingbirds, which have an unique and clearly derived condition, the number of mep bands along a column of fibers near the shoulder falls within a remarkably small range. The number of segments is not obviously related to phylogenetic relatedness or to any characteristic of flight or ecology and is only slightly related to size. The largest specimens do average more segments per column, but there are no trends among small to medium-sized species, suggesting that there is an upper limit to fiber length. However, the shape of the sternum and pattern of connective tissue in the pectoralis alleviate the need for additional fibers in many large birds. These findings suggest that the architecture of the avian pectoralis is subject to some as yet unexplained selection that stabilizes the number of myofibers and/or motor neurons. The findings provide few clues as to whether the significant factors are phylogenetic, functional, ontogenetic, or some combination of these. © 1993 Wiley-Liss, Inc.

Mechanics of glochidial attachment (Mollusca: Bivalvia: Unionidae).

Glochidia are third-class levers in which the valves form the lever arms and the single adductor muscle produces the force. In this study the lengths of the lever arms and the areas of glochidial valves and adductor muscles were determined for 57 species of unionid glochidia. The position of the adductor muscle relative to the dorsal margin of the larval valve was also determined for each species. From these data and an analysis of the possible configurations of adductor muscle and valve dimensions, we determined that most of the glochidia within the Unionidae emphasize area of sweep during valve adduction. These glochidia possess long resistance arms and short force arms and generally had small-diameter adductor muscles. Other glochidia, however, were found to possess one or all of the following: short resistance arms, long force arms, and large-diameter adductor muscles. It is suggested that these glochidia are adapted for strength of valve adduction and that for these larvae a trade-off exists between strength of valve adduction and acceptable valve gape. Furthermore, this study suggests that the mode of attachment employed by glochidia has played a major role in the development of these bivalve larvae and has produced convergence in valve shape and adductor muscle size.

Isolation and culture of synovial microvascular endothelial cells. Characterization and assessment of adhesion molecule expression.

OBJECTIVE: In vitro studies investigating the role of the synovial endothelium in the pathogenesis of rheumatoid arthritis (RA) have, until recently, been performed using cultured endothelial cells of nonsynovial macrovascular origin. In an attempt to more correctly model in vivo conditions, a method for the isolation and culture of synovial microvascular endothelial cells (SMEC) has been developed. METHODS: SMEC were isolated, primarily, by the use of lectin-coated (Ulex europaeus agglutinin type I), magnetizable polystyrene beads. RESULTS: Isolated cells exhibit classic endothelial "cobblestone" morphology, express von Willebrand factor, metabolize acetylated low-density lipoprotein, and exhibit a cytokine (interleukin-1)-mediated expression of endothelial leukocyte adhesion molecule type 1 (ELAM-1) and intercellular adhesion molecule type 1 (ICAM-1). ELAM-1 levels were significantly elevated in SMEC, compared with human umbilical vein endothelial cells, over a range of interleukin-1 concentrations. CONCLUSION: This increased expression of ELAM-1 by SMEC may be a potentiating step in the pathogenesis of RA.

Modulation of arachidonic acid release and membrane fluidity by albumin in vascular smooth muscle and endothelial cells.

Albumin is the major plasma protein circulating in blood. Albumin potently decreases capillary permeability, although the mechanisms are not understood completely. Albumin also effectively binds arachidonic acid (AA), which increases capillary permeability. To investigate the interactions of BSA and AA with the cell membrane, the effect of these substances on [3H]AA release and membrane fluidity was studied in vascular myocytes and endothelial cells. BSA (0.2 and 1 mg . mL-1) stimulated a significant release of [3H]AA from both intact rat aorta and cultured smooth muscle cells. This effect was not mimicked by gamma-globulin or myoglobin (both 1 mg . mL-1) in intact tissue. BSA, but not gamma-globulin and myoglobin, decreased the membrane fluidity (assessed as changes in the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3, 5-hexatriene) in a concentration-dependent manner with a half-maximum concentration between 0.007 and 0.4 mg . mL-1 in both freshly isolated and cultured rat aortic myocytes and human umbilical vein endothelial cells. AA (1 to 200 micromol/L) caused the opposite effect, increasing membrane fluidity and antagonizing the effect of BSA. BSA modified at its arginine residues, which are thought to be important in AA binding, did not stimulate [3H]AA release and was significantly less potent than native BSA in altering the membrane fluidity. The effect of BSA can be explained by a high-affinity binding of AA to the protein and extraction of AA from the cell membrane. The interaction between BSA and AA could play a role in the regulation of vascular permeability.

Biased utilization of immunoglobulin variable region heavy- and light-chain genes by the malignant CD5- B lymphocytes from patients with Burkitt's lymphoma.

Twenty-six established Burkitt's lymphoma (BL) cell lines from endemic or sporadic groups of patients were examined for the expression of cross-reactive idiotypes (CRI) associated with VHI, VHIII, VHIV, VHVI, VKIIIa and VKIIIb heavy- and light-chain gene products, using a panel of anti-CRI and anti-subgroup monoclonal antibodies (MAbs). Membrane, cytoplasmic and secreted immunoglobulins (Ig) were analysed by immunofluorescence, immunoperoxidase and ELISA respectively. While 35% of the lines expressed either of the VHIV-associated CRI, recognised by the MAbs 9G4 or LCI, none expressed the other VH-associated CRI included in our study. Of the kappa light chain expressing BL lines 54% and 46% belonged to the VKIII subgroup and VKIIIb sub-subgroups respectively. None, however, was found to express the VKIIIa or VKIIIb-associated CRI, recognised by the 6B6.6 and 17-109 MAbs. A significant association has been observed between the expression of the VHIV-associated CRI and the VKIII subgroup within the BL lines derived from the sporadic group of patients as compared with their endemic counterparts. Our results suggest that the expressed repertoire of Ig variable region genes within the malignant B lymphocytes of BL is not random and that a highly selective mechanism(s) may operate on this subset of B lymphocytes, as evidenced by the expression of the VH and VK gene products.