Regulation of extracellular matrix remodeling and MMP-2 activation in cultured rat adrenal medullary endothelial cells

We previously reported that short term exposure of cultured rat adrenal medullary endothelial cells (RAMEC) to thrombin enhances the subendothelial deposition of extracellular matrix (ECM) proteins fibronectin, laminin, and collagen types I (C-I) and IV (C-IV) (Papadimitriou et at., 1997). In this work, we extended our previous studies on factors that affect ECM protein deposition to include agents that activate or inhibit some of the most common intracellular signals such as cAMP, protein kinase C (PKC) and calcium. Furthemore, we investigated the possible link between the observed alterations in ECM protein deposition and the secretion of matrix metalloproteinase-2 (MMP-2). Forskolin (adenylyl cyclase activator) caused a dose-dependent increase in the deposition of all four ECM proteins studied. Isoproterenol (beta-adrenergic receptor agonist) and the membrane-permeant cAMP analogue dibutyryl-cAMP, significantly increased the deposited amounts of ECM proteins at low concentrations, and this increase was reversed at higher concentrations of both agents. All these agents had the opposite effect on MMP-2 secretion, increasing it at doses where they decreased ECM protein deposition and vice-versa. However, elevation of cAMP by the phosphodiesterase inhibitor IBMX had no effect neither on the deposited amounts of any of the ECM proteins studied nor on MMP-2 secretion. Activation of PKC by phorbol ester (PMA) resulted in a decrease in ECM protein deposition and an increase in MMP-2 secretion. Finally, chelation of intercellular calcium with BAPTA-AM resulted in an increased ECM deposition and a decrease in MMP-2 secretion, Our results show a complex pattern of regulation of ECM protein deposition by cAMP-mobilizing agents, and also indicate an inverse correlation between ECM protein deposition and secretion of MMP-2. The concerted regulation of both these processes is essential in the formation of new blood vessels and for the integrity of the vascular wall.

Donor lung pretreatment with surfactant in experimental transplantation preserves graft hemodynamics and alveolar morphology

In experimental lung transplantation, the reduction of endogenous surfactant properties occurs after graft preservation and transplant reperfusion. The aim of this study was to evaluate the efficacy of donor lung pretreatment with exogenous surfactant on graft damage after ischemia and reperfusion. Fourteen (control group A, n = 8; study group B, n= 6) young female white pigs (mean weight 27 +/- 3.5 kg) were used in a newly developed autotransplantation model within situcold ischemia. In study group B, before thoracotomy, 1.5 ml/kg surfactant apoprotein-A-free surfactant was administrated into the left main bronchus via flexible bronchoscopy. Belzer UW solution was used for lung preservation. Cold ischemia was achieved for 3 hr with interlobar lung parenchyma temperature at 8 +/- 1.3 degrees C, and central temperature maintained at 37.20 +/- 0.5 degrees C. Animals were sacrificed after 3 hr of graft reperfusion. At the end of reperfusion, pulmonary vascular resistance index (was 447.80 dyn/sec.cm(5).m(2)(+/-66.8) in group A vs 249.51 in group B (P< 0.001) and serum nitric oxide was adequately preserved. The mean alveolar surface area estimated by computerized morphometry was 5280.84 (4991.1) microm(2)(group A) vs 3997.89 (3284.70) microm(2)(group B;P< 0.005). Histology revealed milder macrophage and lymphocyte infiltration in group B at the end of reperfusion. Pretreatment of donor lung with an surfactant apoprotein-A -free surfactant agent appears to be beneficial in terms of maintaining serum NO and reducing hemodynamic disturbances. Furthermore, alveolar histology and stereomorphology are better preserved.

Crimean-Congo hemorrhagic fever in Albania, 2001

During the spring and summer of 2001, an outbreak of eight cases of Crimean-Congo hemorrhagic fever (CCHF) occurred in Albania. The epidemiological investigation, the clinical presentation of the cases, and the course of the disease are described. Seven of the cases were laboratory confirmed. A nosocomial infection and a cluster of cases within a family were observed. Genetic analysis of the CCHF virus strain that caused the outbreak showed that it was clustered together with other European CCHF virus strains except the Greek one (strain AP92). The Greek strain, which forms an independent clade, differed from the causative strain by 25.3% at the nucleotide level.

Nitration of cytoskeletal proteins in the chicken embryo chorioallantoic membrane

Protein tyrosine nitration is one of the post-translational modifications that alter the biological function of proteins. Two important mechanisms are involved: peroxynitrite formation and myeloperoxidase or eosinophil peroxidase (EPO) activity. In the present work we studied the nitration of proteins in the in vivo system of chicken embryo chorioallantoic membrane (CAM). 3-Nitrotyrosine was detected only in the insoluble fraction of the CAM homogenate. By immunoprecipitation, Western blot analysis, and double immunofluorescence, we identified two major polypeptides that were nitrated: actin and alpha-tubulin. Quantification of actin and alpha-tubulin nitration revealed that they are differentially nitrated during normal development of the chicken embryo CAM. After irradiation, although they were both increased, they required different time periods to return to the physiological levels of nitration. It seems that both peroxynitrite formation and EPO activity are involved in the in vivo tyrosine nitration of cytoskeletal proteins. These data suggest that tyrosine nitration of cytoskeletal proteins has a physiological role in vivo, which depends on the protein involved and is differentially regulated.

X-rays modulate extracellular matrix in vivo

X-rays have an antiangiogenic effect in the chicken embryo chorioallantoic membrane (CAM) model of in vivo angiogenesis. Our study demonstrates that X-rays induce an early apoptosis of CAM cells, modulate the synthesis and deposition of extracellular matrix (ECM) proteins involved in regulating angiogenesis and affect angiogenesis induced by tumour cells implanted onto the CAM. Apoptosis was evident within 1-2 hr, but not later than 6 hr after irradiation. Fibronectin, laminin, collagen type I, integrin alpha(v)beta3 and MMP-2 protein amounts were all decreased 6 hr after irradiation. In contrast, collagen type IV, which is restricted to basement membrane, was not affected by irradiation of the CAM. There was a similar decrease of gene expression for fibronectin, laminin, collagen type I and MMP-2, 6 hr after irradiation. The levels of mRNA for integrin alpha(v)beta3 and collagen type IV were unaffected up to 24 hr after irradiation. The decrease in both protein and mRNA levels was reversed at later time points and 48 hr after irradiation, there was a significant increase in the expression of all the genes studied. When C6 glioma tumour cells were implanted on irradiated CAMs, there was a significant increase in the angiogenesis induced by tumour cells, compared to that in non-irradiated CAMs. Therefore, although X-rays have an initial inhibitory effect on angiogenesis, their action on the ECM enhances new vessel formation induced by glioma cells implanted on the tissue.

Interactions of PC/Chol and PS/Chol liposomes with human cells in vitro

Interactions between phosphatidylcholine (PC) or phosphatidylserine (PS) liposomes and human umbilical vein endothelial cells (HUVEC) or human promyelocytic leukemia cells (HL60) were investigated. Pyramine encapsulating or rhodamine incorporating small unilamellar liposomes with mean diameters around 80 nm (demonstrated to retain encapsulated material and to be nontoxic under experimental conditions) were used. Liposome uptake by both types of cells increased when increasing amounts of vesicles were co-incubated. For both lipid compositions, the interaction with HUVEC was very fast (association reached a plateau within 5 min) and so was the release of internalized vesicles (90% within 10 min at 37 degrees C). The reduced association values at 4 degrees C and the punctuate fluorescence observed in the cell cytoplasm after interaction, were indicative of whole liposome internalization. This internalization was clathrin-independent, since it was not inhibited by sodium azide and deoxyglucose. Pre-treatment of HUVEC with filipin or NEM resulted in modification of the interaction, something that could be due to alterations in the biochemical characteristics of HUVEC membranes that inhibit vesicular processes. In HL-60 cells, a slower association and faster release of PC/Chol liposomes was demonstrated, while association of both liposomes with these cells was energy-and temperature-independent. Nevertheless, morphological studies revealed differences in the interactions: A bright fluorescent rim observed after interaction with PC/Chol liposomes, suggests that these liposomes were adsorbed on the surface of HL60 cells, while the uniform cytoplasmic fluorescence observed after incubation with PS/Chol liposomes was indicative of fusion as the interaction mechanism.

HARP induces angiogenesis in vivo and in vitro: implication of N or C terminal peptides

HARP (heparin affin regulatory peptide) is a growth factor displaying high affinity for heparin. In the present work, we studied the ability of human recombinant HARP as well as its two terminal peptides (HARP residues 1-21 and residues 121-139) to promote angiogenesis. HARP stimulates endothelial cell tube formation on matrigel, collagen and fibrin gels, stimulates endothelial cell migration and induces angiogenesis in the in vivo chicken embryo chorioallantoic membrane assay. The two HARP peptides seem to be involved in most of the angiogenic effects of HARP. They both stimulate in vivo angiogenesis and in vitro endothelial cell migration and tube formation on matrigel. We conclude that HARP has an angiogenic activity when applied exogenously in several in vitro and in vivo models of angiogenesis and its NH(2) and COOH termini seem to play an important role.

Endothelial cell proliferation induced by HARP: implication of N or C terminal peptides

HARP (Heparin Affin Regulatory Peptide) is a 18-kDa secreted protein displaying high affinity for heparin. It has neurite outgrowth-promoting activity, while there are conflicting results regarding its mitogenic activity. In the present work, we studied the effect of human recombinant HARP expressed in bacterial cells as well as two peptides (HARP residues 1-21 and residues 121-139) on the proliferation of three endothelial cell types derived from human umbilical vein (HUVEC), rat adrenal medulla (RAME), and bovine brain capillaries (BBC) either added as a soluble form in the cell culture medium or coated onto the culture plate. HARP added in a soluble form in the culture medium had no effect on the proliferation of BBC, HUVEC, and RAME cells. However, when immobilized onto the cell culture plate, HARP had a concentration-dependent mitogenic effect on both BBC cells and HUVEC. The peptides presented as soluble factor induced a significant concentration-dependent mitogenic effect on BBC cells but only a small effect on HUVEC and RAME cells. When they were immobilized onto the cell culture plate, the mitogenic effect was much greater. The most responsive cells were BBC that expressed and secreted in the culture medium the higher amounts of HARP.

HIV-1 co-receptor CCR5 and CCR2 mutations among Greeks

The frequency of CCR5 and CCR2 alleles in human immunodeficiency virus (HIV)-positive and HIV-negative populations of Northern Greece was investigated. The frequency of the CCR5Delta32 allele among the HIV-negative subjects was 0.052, while it was approximately two-fold lower among the seropositives, suggesting that the heterozygous genotype confers a partial resistance to the HIV infection. No significant difference in CCR2 allele frequency between the two groups was observed.

Nitric oxide synthase expression, enzyme activity and NO production during angiogenesis in the chick chorioallantoic membrane

In order to elucidate further the role of nitric oxide (NO) as an endogenous antiangiogenic mediator, mRNA expression of inducible nitric oxide synthase (iNOS), enzyme activity and production of NO were determined in the chick chorioallantoic membrane (CAM), an in vivo model of angiogenesis. In this model, maximum angiogenesis is reached between days 9 - 12 of chick embryo development. After that period, vascular density remains constant. Inducible NO synthase (iNOS) mRNA expression, determined by reverse transcriptase polymerase chain reaction (RT - PCR), increased from the 8th day reaching a maximum (70% increase) at days 10 - 11. NO synthase activity, determined as citrulline formation in the presence of calcium, also increased from day 8 reaching a maximum around day 10 (100% increase). Similar results were obtained in the absence of calcium suggesting that the NOS determined was the inducible form. Nitric oxide production, determined as nitrites, increased from day 8 reaching a maximum around day 10 (64% increase) and remaining stable at day 13. Finally, the bacterial lipopolysaccharide LPS (which activates transcriptionally iNOS), inhibited dose dependently angiogenesis in the CAM. These results in connection with previous findings from this laboratory, showing that NO inhibits angiogenesis in the CAM, suggest that increases in iNOS expression, enzyme activity and NO production closely parallel the progression of angiogenesis in the CAM, thus providing an endogenous brake to control this process. British Journal of Pharmacology (2000) 129, 207 - 213

Evidence that platelets promote tube formation by endothelial cells on matrigel

The involvement of platelets in neovascularization was investigated in the matrigel tube formation assay, an in vitro model of angiogenesis. Platelets promoted the formation of capillary-like structures (expressed as relative tube area) number- and time-dependently. Relative tube area increased from 0.98+/-0.02 (n = 8) in the presence of 6.25 x 10(4), to 3.21+/-0.12 (n=8) in the presence of 10(6) platelets/well compared to 0.54+/-0.04 (n=8) in their absence. This increase was unaffected by acetyl salicylic acid (ASA), apyrase, and hirudin. Photographs from representative experiments, showed that platelets adhered along the differentiating endothelium. Addition of alpha-thrombin (0.1-1 i.u. ml(-1)), the nitric oxide (NO) donor sodium nitroprusside (SNP; 1-100 microM) or the NO synthase inhibitor, L-NG-arginine-methylester (L-NAME, 30-300 microM) to the assay, had no effect on tube formation compared to that seen with platelets alone. Neuraminidase (0.01 i.u./10(7) platelets), which strips sialic acid residues from membrane glycoproteins, abolished the promoting effect of platelets on tube formation. The relative tube area in the presence of neuraminidase-treated platelets was 0.81+/-0.03 (n = 8), in the presence of untreated platelets 1.69+/-0.09, P<0.001 (n=8) and in the absence of platelets, 0.80+/-0.04 (n=8). The tetrapeptide Arg-Gly-Asp-Ser (RGDS; 20-200 microM) which inhibits von Willebrand factor, fibrinogen and fibronectin-mediated adhesion, had no effect on the promoting effect of platelets on tube formation. These results indicate that platelets promote angiogenesis in vitro. This effect is largely independent from activation by alpha-thrombin, is not modified by manipulating NO and prostaglandin metabolism and proceeds possibly through adhesion of the platelets to the differentiating endothelium.

The heat shock 70 gene family in the Mediterranean fruit fly Ceratitis capitata

The cloning and the characterization of the heat shock 70 (hsp70) genes of the medfly C. capitata, a major agricultural pest, are presented. Six genomic clones were isolated by screening a medfly genomic library with an hsp70 genomic fragment of Drosophila melanogaster. They form two 30 kb contigs, both of which map cytogenetically in a single major heat shock puff (3L:24C) of the salivary gland polytene chromosomes. Restriction mapping and blot hybridization indicated the presence of six putative hsp70 genes in these two closely linked regions. The sequence of one of these genes suggests that it is a heat-inducible hsp70 gene. The 638-codon open reading frame shows 84% identity at the amino acid level (73.5% at the nucleotide level), relative to corresponding D. melanogaster sequences. The 5' untranslated leader sequence, approximately 200 bp long, is not interrupted by introns and is very rich (48%) in adenine residues, resembling Drosophila heat-inducible hsp70 genes. Furthermore, the promoter of this gene contains two characteristic heat shock elements close upstream from the TATA box. The levels of the hsp70 transcripts are very low at 25-30 degrees C, increase significantly at 33 degrees C and reach maximum at 39 degrees C.

Cholera toxin stimulates human B-cell DR antigen biosynthesis at the level of translation

Cholera toxin (CT) exerts many diverse regulatory effects on cells of the immune system and is considered a potent adjuvant on gut mucosal immune responses to orally presented antigens. It has been previously described that CT induces surface DR expression in human resting B-cells. As a further step toward understanding this phenomenon, the molecular mechanisms underlying the regulation of DR expression were investigated. By the use of Western analysis, it is shown that CT increases the total levels of DR protein in highly purified human tonsillar cells. [35S]Methionine incorporation studies show that the aforementioned increase is due to de novo biosynthesis of DR protein at as early as 6 hr after CT stimulation and is completed by 24 hr. [3H]Uridine uptake experiments, nuclear transcription runoff assays, and Northern analysis show that CT does not exert its effect at a transcriptional level, indicating translational regulation. Anti-IgM, which mimics B-cell antigen binding, behaves in a manner similar to CT. The B subunit of CT (B-CT) and prostaglandin E2, either alone or in combination, do not induce DR protein biosynthesis nor do they exert any effect on the transcription of DR beta 1 gene. These results show that cAMP elevation as well as binding of B-CT to GM-1 ganglioside, by themselves, do not lead to DR protein biosynthesis suggesting that other activation pathways may be involved.

Thrombin modulates vectorial secretion of extracellular matrix proteins in cultured endothelial cells

We have identified a novel cellular action of thrombin on cultured rat adrenal medullary endothelial cells (RAMEC). Five-minute incubation of RAMEC with physiological concentrations of thrombin (<1 U/ml) caused within 3 h an increase in the basolateral deposition of the extracellular matrix (ECM) proteins fibronectin, laminin, and collagens IV and I, concomitant with a corresponding decrease in the apical release of these proteins into the medium. This shift in vectorial secretion of ECM proteins, quantitated with enzyme-linked immunoassays, was time dependent. Maximal stimulation of ECM protein deposition was observed after incubation of cells with thrombin for 5-15 min. Prolonged exposure (>1 h) to thrombin resulted in loss of proteins from the ECM. Thrombin-stimulated ECM protein deposition exhibited a bell-shaped dose dependence, peaking for all proteins at 0.25 U/ml of thrombin, and was independent of de novo mRNA or protein synthesis. Maximal amounts of deposited proteins increased between 2.5-fold (fibronectin) and 4-fold (collagen I) over baseline values. Similar results were obtained with thrombin receptor agonist peptide (TRAP), proteolytically active gamma-thrombin, and, to a lesser extent, other serine proteases such as trypsin and plasmin. A scrambled TRAP, proteolytically inactive PPACK-thrombin, DIP-thrombin, and type IV collagenase were ineffective. Together, these results suggest that the thrombin effects are mediated by proteolytic activation of the thrombin receptor. Possible involvement of the phospholipase C-signaling pathway in thrombin-mediated ECM protein deposition was also investigated. Inhibition or downregulation of protein kinase C (PKC) and chelation of intracellular or extracellular Ca2+ did not suppress, but rather enhanced, basal and thrombin-stimulated ECM protein deposition. Quantitative differences in augmentation of basolateral deposition by these treatments suggest differential regulatory pathways for individual ECM proteins. Our data indicate that, in cultured RAMEC, short-term activation of the thrombin receptor causes an increase in amounts of deposited ECM protein by a cellular signaling pathway that is independent of PKC activation and/or elevation of intracellular Ca2+.

Myoglobinuria due to quail poisoning

Quail poisoning is known to produce an acute myoglobinuric syndrome. The cause of this syndrome is still unknown. It has been suggested that a toxic effect or a genetic sensitivity plays a major role. Ten patients with a history of quail poisoning were examined to determine their present state and the course of the disease. A muscle biopsy was performed in 2 of these patients who complained of muscle cramps after exercise. The activities of several glycolytic mitochondrial and lipolytic enzymes were estimated. In all 10 patients the physical examination, electromyogram findings and conduction velocities were normal. Serum levels of CK, aldolase and lactic acid were also within normal range. In the 2 patients with cramps, all enzyme activities were normal in muscle tissue. Our findings possibly exclude a preexisting enzyme defect as a cause of myoglobinuria in quail poisoning. Considering that 4 of our patients continued the consumption of quails without further problems, we suggest that the major factor contributing to quail poisoning must be toxic.

Measurement of cell numbers in microtiter culture plates using the fluorescent dye Hoechst 33258

A sensitive fluorimetric assay based on DNA binding of the fluorescent dye Hoechst 33258 was developed to quantitate cell numbers in microtiter plates. The cells were fixed and incubated with the dye solution. The bound dye was extracted with ethanol and fluorescence was measured in a spectrofluorimeter. The method is sensitive for as little as a thousand cells and is particularly useful for the normalization of enzyme-linked immunoassay (ELISA) data obtained from the same cells. Another major advantage of this new technique is that in contrast to previously described methods, it requires commonly available, inexpensive equipment.

McArdle's disease: two clinical expressions in the same pedigree

Two patients with McArdle's disease within the same pedigree and with two different clinical forms are presented. The first patient suffered from progressive muscle weakness and atrophy. Muscle morphology was that of myopathy. Residual activity of phosphorylase was 28% and sodium dodecyl sulphate electrophoresis showed decreased protein. The second case was typical of McArdle's disease, clinically and biochemically. It was concluded that the first patient was a heterozygote (residual activity 28% of normal) and the second was a homozygote, the genetic transmission being autosomal recessive.

[Organization of a central supply system for nursing units]

The provision of supplies for a hospital, wards and nursing units, must be undertaken carefully. The financial side as well as the suitability and the quality of the equipment must be taken into consideration for an effective patient nursing care. A central supply system for a hospital is considered as a more economical and effective one. By this way nursing staff relieved from no nursing duties, thus they can devote more time to direct patient care in the unit.