New findings on venous thrombogenesis

Venous thrombosis (VT) is the third most common cause of cardiovascular death worldwide. Complications from VT and pulmonary embolism are the leading cause of lost disability-adjusted life years. Risks include genetic (e.g., non-O blood group, activated protein C resistance, hyperprothrombinemia) and acquired (e.g., age, surgery, cancer, pregnancy, immobilisation, female hormone use) factors. Pathophysiologic mechanisms that promote VT are incompletely understood, but involve abnormalities in blood coagulability, vessel function, and flow (so-called Virchow's Triad). Epidemiologic studies of humans, animal models, and biochemical and biophysical investigations have revealed contributions from extrinsic, intrinsic, and common pathways of coagulation, endothelial cells, leukocytes, red blood cells, platelets, cell-derived microvesicles, stasis-induced changes in vascular cells, and blood rheology. Knowledge of these mechanisms may yield new therapeutic targets. Characterisation of mechanisms that mediate VT formation and stability, particularly in aging, are needed to advance understanding of VT.

Clinical efficacy of sustained-release buprenorphine with meloxicam for postoperative analgesia in beagle dogs undergoing ovariohysterectomy

The goal of the current study was to compare the efficacy, adverse effects, and plasma buprenorphine concentrations of sustained-release buprenorphine (SRB) and buprenorphine after subcutaneous administration in dogs undergoing ovariohysterectomy. In a prospective, randomized, blinded design, 20 healthy adult female Beagle dogs underwent routine ovariohysterectomy and received multimodal analgesia consisting of meloxicam and one of two buprenorphine formulations. Dogs were randomly assigned to receive either SRB (0.2 mg/kg SC, once) or buprenorphine (0.02 mg/kg SC every 12 h for 3 d). Blinded observers assessed all dogs by using sedation scores, pain scores, temperature, HR, RR, and general wellbeing. Dogs were provided rescue analgesia with 0.02 mg/kg buprenorphine SC if the postoperative pain score exceeded a prede- termined threshold. Blood samples were collected, and mass spectrometry was used to determine plasma buprenorphine concentrations. Data were analyzed with a linear mixed model and Tukey-Kramer multiple comparison. Age, body weight, anesthetic duration, surgical duration, sevoflurane concentration, and cardiorespiratory variables did not differ significantly between groups. Dogs in both formulation groups had comparable postoperative sedation and pain scores. One dog from each formulation group had breakthrough pain requiring rescue analgesia. Plasma buprenorphine concentrations remained above a hypothesized therapeutic concentration of 0.6 ng/mL for 136.0 ± 11.3 and 10.67 ± 0.84 h for SRB and buprenorphine, respectively. Based on the results of this study, multimodal analgesic regimens consisting of meloxicam and either buprenorphine or SRB are equally efficacious in managing pain associated with an ovariohysterectomy and show comparable side effects.

Contribution of endothelial injury and inflammation in early phase to vein graft failure: the causal factors impact on the development of intimal hyperplasia in murine models

OBJECTIVES

Autologous veins are preferred conduits in by-pass surgery. However, long-term results are hampered by limited patency due to intimal hyperplasia. Although mechanisms involved in development of intimal hyperplasia have been established, the role of inflammatory processes is still unclear. Here, we studied leukocyte recruitment and intimal hyperplasia in inferior vena cava grafts transferred to abdominal aorta in mice.

METHODS AND RESULTS

Several microscopic techniques were used to study endothelium denudation and regeneration and leukocyte recruitment on endothelium. Scanning electron microscopy demonstrated denudation of vein graft endothelium 7 days post-transfer and complete endothelial regeneration by 28 days. Examination of vein grafts transferred to mice transgenic for green fluorescent protein under Tie2 promoter in endothelial cells showed regeneration of graft endothelium from the adjacent aorta. Intravital microscopy revealed recruitment of leukocytes in vein grafts at 7 days in wild type mice, which had tapered off by 28 days. At 28 and 63 days there was significant development of intimal hyperplasia. In contrast; no injury, leukocyte recruitment nor intimal hyperplasia occurred in arterial grafts. Leukocyte recruitment was reduced in vein grafts in mice deficient in E- and P-selectin. In parallel, intimal hyperplasia was reduced in vein grafts in mice deficient in E- and P-selectin and in wild type mice receiving P-selectin/E-selectin function-blocking antibodies.

CONCLUSION

The results show that early phase endothelial injury and inflammation are crucial processes in intimal hyperplasia in murine vein grafts. The data implicate endothelial selectins as targets for intervention of vein graft disease.

Glycosaminoglycan sulodexide modulates inflammatory pathways in chronic venous disease

Inflammation represents an important epiphenomenon in the etiopathogenesis of chronic venous disease, a worldwide debilitating condition affecting millions of subjects. The pathophysiology of chronic venous disease (CVD) is based on the hemodynamic abnormalities in conjunction to alterations in cellular and extracellular matrix biocompounds. The endothelial dysfunction results from early perturbation in the endothelium linked to glycocalyx injury and promoted by inflammatory cells and mediators (such as matrix metalloproteinases and interleukins), which lead to progressive dilation of the vein resulting in chronic venous insufficiency. Activated leukocytes during the inflammatory process release enzymes, free radicals, chemokines and inflammatory cytokines in the vessel microenvironment, which are responsible for the changes of the venous wall and venous valve, reflux and venous hypertension, and the development/progression of tissue destruction and skin changes. Sulodexide, a highly purified mixture of glycosaminoglycans composed by 80% fast moving heparin and 20% of dermatan sulphate, exhibits anti-thrombotic and profibrinolytic properties, restoring also the essential endothelial glycocalyx. Glycosaminoglycan sulodexide has been also characterized to reduce the release of inflammatory cytokines/chemokines and to inhibit the matrix metalloproteinases-related proteolytic cascades, counteracting endothelial dysfunctions. The pleiotropic effects of sulodexide set the basis for a very promising agent in treating the spectrum of CVD.

Low levels of a natural IgM antibody are associated with vein graft stenosis and failure

BACKGROUND

All humans have natural, protective antibodies directed against phosphorylcholine (PC) epitopes, a common inflammatory danger signal appearing at sites of cell injury, oxidative stress, and on bacterial capsules. In large human cohorts, low levels of anti-PC IgM were associated with a significantly increased risk of stroke or myocardial infarction. However, it is not known if these antibodies protect against the premature closure of arterial reconstructions.

METHODS

A prospective, observational study of patients undergoing elective, infrainguinal, autogenous vein bypasses for atherosclerotic occlusive disease of the legs was conducted. Clinical data were recorded prospectively, and preoperative levels of anti-PC IgM measured with the CVDefine kit from Athera Biotechnologies (Solna, Sweden). The principal clinical end point was the loss of primary patency (loss of graft flow, or any intervention for stenosis). Patients were followed regularly by duplex ultrasound at 1, 3, 6, 12, 18 months, and yearly thereafter.

RESULTS

Fifty-six patients were studied, for an average of 1.3 years. Indications for surgery were claudication (33.9%), ischemic rest pain (17.9%), and ischemia with ulceration or gangrene (48.2%). Seventeen (30.4%) patients experienced loss of primary patency (10 graft occlusions, seven surgical or endovascular revisions of graft stenoses). Kaplan-Meier survival analysis showed that the quartile of patients with the lowest anti-PC IgM levels had significantly worse primary graft patency (log-rank test, P = .0085). Uni- and multivariate Cox proportional hazards analysis revealed that the preoperative anti-PC IgM level was an important predictor of graft failure. Patients with IgM values in the lowest quartile had a 3.6-fold increased risk of graft failure (95% confidence interval: 1.1-12.1), even after accounting for other significant clinical or technical factors such as indication for surgery, site of distal anastomosis, or vein graft diameter.

CONCLUSIONS

A naturally occurring IgM antibody directed against the proinflammatory epitope PC may be protective against vein graft stenosis and failure, through anti-inflammatory mechanisms. Measurement of this antibody may be a useful prognostic indicator, although larger studies of more diverse populations will be needed to confirm these results. The biological actions of anti-PC IgM suggest it may be useful in developing immunotherapies to improve bypass longevity.

Accelerated immunopathological response of mice infected with Mycobacterium tuberculosis disrupted in the mce1 operon negative transcriptional regulator

Mycobacterium tuberculosis causes a variety of clinical outcomes determined by host as well as bacterial factors. M. tuberculosis disrupted in the mce1 operon causes increased mortality in immunocompetent mice. This operon is negatively regulated by mce1R (Rv0165c). We studied the role of mce1R in infection outcome in mice. At 5 x 10(4) tail vein infectious dose, the median survival time (MST) of mice infected with the mce1R mutant M. tuberculosis H37Rv was 293 days, while mice infected with the wild-type H37Rv survived more than 350 days (P < 0.0001). At a higher dose (5 x 10(6)), the MST of mutant-infected mice was 32 days, compared with 127 days for wild type-infected mice (P < 0.0001). With either tail vein or aerosol infection, mutant-infected mice developed larger granulomatous lesions in their lungs than mice infected with the wild type. Mutant-infected mice were unable to control the bacterial burden in the first 4 weeks of infection, but even after achieving control later, these mice succumbed to granulomatous pneumonia. These observations suggest that the early deregulated expression of the mce1 operon products determines later granulomatous tissue response. mce1 operon may homeostatically regulate the cell wall architecture in vivo that elicits a steady-state granuloma tissue response permitting M. tuberculosis to establish a long-term infection.

Mitochondrial reactive oxygen species regulate spatial profile of proinflammatory responses in lung venular capillaries

Cytokine-induced lung expression of the endothelial cell (EC) leukocyte receptor P-selectin initiates leukocyte rolling. To understand the early EC signaling that induces the expression, we conducted real-time digital imaging studies in lung venular capillaries. To compare receptor- vs nonreceptor-mediated effects, we infused capillaries with respectively, TNF-alpha and arachidonate. At concentrations adjusted to give equipotent increases in the cytosolic Ca(2+), both agents increased reactive oxygen species (ROS) production and EC P-selectin expression. Blocking the cytosolic Ca(2+) increases abolished ROS production; blocking ROS production abrogated P-selectin expression. TNF-alpha, but not arachidonate, released Ca(2+) from endoplasmic stores and increased mitochondrial Ca(2+). Furthermore, Ca(2+) depletion abrogated TNF-alpha responses partially, but arachidonate responses completely. These differences in Ca(2+) mobilization by TNF-alpha and arachidonate were reflected in spatial patterning in the capillary in that the TNF-alpha effects were localized at branch points, while the arachidonate effects were nonlocalized and extensive. Furthermore, mitochondrial blockers inhibited the TNF-alpha- but not the arachidonate-induced responses. These findings indicate that the different modes of Ca(2+) mobilization determined the spatial patterning of the proinflammatory response in lung capillaries. Responses to TNF-alpha revealed that EC mitochondria regulate the proinflammatory process by generating ROS that activate P-selectin expression.

Antigen uptake and immunoglobulin production in Atlantic cod (Gadus morhua L.) after intraperitoneal injection of Vibrio anguillarum

Atlantic cod (Gadus morhua L.) were injected intraperitoneally with formalin-killed Vibrio anguillarum bacteria. Immunostaining revealed uptake of V. anguillarum antigens especially in the spleen after intraperitoneal (i.p.) administration. The uptake was time dependent in the interval 1-24 h. Most of the antigen uptake in the spleen was concentrated in areas around small blood vessels, while immunoglobulin producing cells were localised to some thick walled arteries. There was apparently little or no co-localisation of antigens and antibody producing cells. In the heart, some of the high endocardial endothelial cells of the atrium contained bacterial antigens and in head kidney some macrophage-like cells were stained. Very little antigen was found in the pigmented loose connective tissues of the peritoneum. In contrast, endothelial cells of the underlying blood vessels contained substantial amounts. In the heart, peritoneum and anterior kidney the number of antigen positive cells did not seem to change in the time interval 1-24 h. After i.p. immunisation with a mixture of V. anguillarum and Freunds complete adjuvant, the humoral immune response in Atlantic cod was low when tested 21, 42 and 105 days later. There was apparently no enhanced number of immunoglobulin synthesising cells caused by the antigen stimulation.

[Regulation of innate immunity during xenogenic changes in blood circulation]

Calcium-dependent innate immune response with participation of the superfamily of immunoglobulins to several intra- and extracorporal xenobiotics were studied at 216 recipients during synthetic cardiac valves implantation or veins transplantation in coronary arteries. It was shown that immediate immune response to xenobiotics was manifested by generation of the antitissue anodical autoprecipitin with specificity to the surface cell membrane component. This reaction initiated and regulated the subsequent dynamics of the two different fibrinogen autoimmune complexes formation, resulting in development of the immunogenic damages of blood circulation. Correction of these rapid innate immune responses is important for prevention and normalisation of the xenogenic damages of blood circulation during trans- and implantation on the heart impaired with endocarditis or aterosclerosis.

[Anti-endothelial cell antibodies in chronic leg ulcer: prevalence and significance]

BACKGROUND

Anti-endothelial cell antibodies are detected in auto-immune vasculitis and connective tissue diseases such as scleroderma, with possible pathogenic involvement. We looked for these antibodies in patients presenting chronic ulcers.

PATIENTS AND METHODS

Eighty patients were tested: 35 presented vascular ulcers (27 of venous origin and 8 arterial). A control group of 14 patients with connective tissue disease and vasculitis was formed, and a third group included 31 patients without vascular or immune disease. Their sera were tested by ELISA technique on EAhy 926 cell (obtained from hybridization of human endothelial and line A 549/8 cells).

RESULTS

Blood tests were positive in 37.5 p. 100 of patients. Antibodies were present in 48.5 p. 100 of patients with leg ulcers (of which 59 p. 100 (16/27) venous ulcers). Fifty-seven per cent of the autoimmune group and 12 p. 100 of the third group were positive. Association with anti-phospholipid antibodies was observed twice in leg ulcers. The level of antibodies was higher in patients with leg ulcers.

COMMENTS

The presence of high levels of anti-endothelial cells antibodies in 48.5 p. 100 of patients presenting leg ulcers shows that these antibodies are not specific to autoimmune diseases. Since they are involved in coagulation, inflammation (enhancing of adhesion molecules and tissue lysis) and apoptosis of endothelial cells, their significance in chronic ulcers, both as a consequence and/or possible cofactor merits discussion.

Expression of beta 1 integrins in human dental pulp in vivo: a comparative immunohistochemical study on healthy and chronic marginal periodontitis samples

AIM

The objective of this study was to determine the tissue distribution of beta 1 integrin chains in sound human dental pulps and to compare the findings with connective tissue compartments of other organs and to pulp tissue in teeth extracted due to periodontal disease.

METHODOLOGY

Freshly frozen pulp tissue samples from teeth extracted for orthodontic reasons were examined and compared to samples from teeth extracted due to chronic (marginal) periodontitis. beta 1 integrin chains were determined using an indirect-immunoperoxidase technique. Seven monoclonal antibodies recognizing alpha 1, alpha 2, alpha 3, alpha 4, alpha 5, alpha 6 and beta 1 chains of Very Late Activation Antigen (VLA) integrins were used for this purpose.

RESULTS

VLA-1, VLA-2, VLA-3 and VLA-5 were expressed by vascular endothelium and vascular smooth muscle in varying intensities in both groups. VLA-6 reactivity was observed in the basal surfaces of arterial, venous and capillary endothelia. Our results indicate that there was no significant difference in the expression of VLA integrins in sound pulp tissue when compared to the samples from chronic (marginal) periodontitis and the connective tissue compartments of other viscera.

CONCLUSION

The present findings suggest that human dental pulp tissue is not different from other connective tissue compartments in the body with respect to VLA integrin expression, and chronic marginal periodontitis does not affect pulp tissue to a histopathologically detectable extent.

[The humoral reactions of bioincompatibility in the early period after the heterotopic autograft of veins into the coronary bed and the implantation of synthetic heart valves]

Humoral manifestations of bioincompatibility were studied at early stages (during several hours and days) after operations using non-peculiar to heart trans- and implants: aortocoronary bypass at 102 patients with coronarosclerosis and implantation of artificial cardiac valves at 145 patients with endocarditis. In the various postoperation stages the formation of the structurally and functionally different types of the nonclonal specific autoprecipitins to autological membranocellular components was revealed at recipients by methods of double immunodiffusion and immunoelectrophoresis. These autoprecipitins such as: early, activated and tardly, synthesized under effect of alien agent--may be useful as diagnostic and prognostic indicators of bioincompatibility and its clinical consequences at the earliest period after cardiac operations using trans- and implants.

Characteristics of gastric-vein lymphocytes with regard to the immune response to Helicobacter pylori

BACKGROUND

Between peripheral blood and tissue-infiltrating lymphocytes there is an intermediate compartment, the blood of the organ-draining vessels, which could show unusual features. The aim of the present study was to analyse the characteristics of the lymphocytes from the stomach-draining vessels and the cytokine secretion by these lymphocytes. The CagA-mediated lymphocyte activation in Helicobacter pylori-infected subjects and the humoral response to this antigen were evaluated and correlated with clinical data.

METHODS

We studied lymphocyte proliferation either with mitogens or with the CagA antigen and cytokine production and IgG anti-CagA by means of an enzyme-linked immunosorbent assay in peripheral blood and gastric-vein blood obtained during surgical intervention.

RESULTS

We showed higher proliferative response and cytokine production in lymphocytes from the gastric vein. The mitogenic response to the CagA antigen was highly specific but poorly sensitive for the H. pylori infection in both the compartments. The overall cytokine profile in our patients affected by non-ulcer disease was of the Th0 type.

CONCLUSIONS

Gastric-vein-derived lymphocytes seem to show unusual features, as they behave like peripheral blood lymphocytes but show higher responses to all the tested stimuli. It is possible that the interaction of the lymphocytes with the mucosal environment could activate the synthetic mechanisms, making the cells more 'responsive' to the stimulation. The CagA antigen is able to induce a specific T-lymphocyte response and is therefore a valid candidate antigen for the development of a vaccine.

Mast cells are augmented in deep vein thrombosis and express a profibrinolytic phenotype

A number of recent data suggest that mast cells (MC) and their products are involved in the pathophysiology of thrombosis. In the current study, we have evaluated the number, distribution, and phenotype of MC in patients with deep vein thrombosis of the lower limb (DVT) (n = 15). Contralateral nonthrombosed limb veins served as control (CO). MC were examined by Giemsa staining and by immunohistochemistry using antibodies against tryptase, chymase, tissue-type plasminogen activator (tPA), urokinase (uPA), urokinase receptor (uPAR), and plasminogen activator inhibitors (PAI-1, PAI-2). We found an increase in the number of tryptase-positive MC in DVT compared with CO (DVT: 9.1+/-1.0 v CO: 4.7+/-0.6 MC/mm2, P < .05). Most of these MC appeared to accumulate in the adventitia of the thrombosed veins, in vicinity of the vasa vasorum. In both DVT and CO, MC reacted with monoclonal antibodies to c-kit, tryptase, and chymase. MC also stained positive for tPA and urokinase receptor, but did not express detectable PAI-1 or PAI-2. As compared with CO, a decreased proportion of MC in DVT was found to stain positive for chymase and tPA. Together, our results show that MC increase in number in DVT and express a profibrinolytic phenotype. We hypothesize that MC and MC-derived profibrinolytic molecules play a role in the pathophysiology of DVT.

Epithelial- and endothelial-cell specificity of renal graft infiltrating T cells

Previously, we have shown that rejecting renal allografts are infiltrated by tissue-specific T cells that in vitro kill proximal tubular epithelial cells (PTEC), while donor-derived splenocytes are not affected. In the current unique study we assessed the reactivity of graft-infiltrating T cells (GIC) for three different donor-derived cell types. Cytotoxicity of GIC was tested against PTEC, as well as donor-derived gonadal vein endothelial cells (GOVEC) and splenocytes. T cells lysed PTEC, GOVEC and splenocytes expressing a mismatched donor HLA antigen, HLA-A29(19). Interestingly, PTEC and GOVEC, not splenocytes, expressing none of the donor HLA antigens were also killed. T cell clones, obtained by limiting dilution cloning of the GIC line, could be divided into different categories: clones recognizing both PTEC and GOVEC expressing the mismatched HLA-A29(19), clones recognizing either PTEC or GOVEC expressing the mismatched HLA-A29(19) and also clones specifically recognizing PTEC or GOVEC independent of donor HLA antigen expression. In conclusion, T cell clones with specificities for either epithelial or endothelial cells exist, leaving a role for tissue-specific antigens in allograft rejection.

Evolution of the schistosomes (Digenea: Schistosomatoidea): the origin of dioecy and colonization of the venous system

Trematodes of the family Schistosomatidae are considered venous system specialists whose sister group is the vascular system generalists (Spirorchidae) of turtles. Colonization of homeotherms by vascular trematodes required precision egg laying near the conduit for egg passage to the external environment and avoidance of pathogenesis that might result in the premature death of the host. Evolution of dioecy from the hermaphroditic condition may have proceeded through androdioecy in which hermaphrodites were specialized for precision egg placement in the vascular system and larger adults became functional males. The evolution of nuclear genes suppressing female function along with cytoplasmic genes suppressing male function could then have resulted in the origin of dioecious, dimorphic populations. Schistosomes compensated for the reduction in potential reproductive partners by (1) increased overdispersion in the vertebrate host, (2) reduced egg hatching time in the external environment, (3) formation of permanent pairs mimicking the hermaphroditic condition, (4) increased longevity in the definitive host, and (5) increased fecundity. Colonization of the venous system was necessitated by (1) evolutionary radiation into terrestrial vertebrates and (2) the increased immunopathology associated with the high, constant body temperature of homeothermic vertebrates. The immune response to spirorchid and schistosome eggs appears to be qualitatively similar in their respective hosts. The arterial dwelling spirorchids release eggs in the direction of blood flow, resulting in a wide dissemination of eggs within the host. The lower body temperature of poikilotherms accompanied by the seasonal nature of the immune response in these hosts would result in a quantitatively reduced pathogenesis. Hosts that did succumb to the infection would most likely die in water, where eggs could be released by predation, scavengers, or decomposition and develop successfully. Colonization of the venous system by schistosomes would require precision egg placement because eggs are released against blood flow. Eggs are sequestered within the portal system of homeotherms, thus restricting egg dispersal and resulting pathogenesis to less sensitive organs. A significant number of eggs may escape into the external environment before a heavily infected host is incapacitated by, or dies from, the infection.

Comparison of capillary blood versus venous blood samples in the assessment of immunity to measles

Seroepidemiological investigations are essential for assessing the efficacy of measles vaccination programmes. However, when large-scale sampling is needed, a major difficulty is the problem of taking venous blood, especially in children. An alternative method is the collection of capillary blood samples spotted on filter papers. The eluted extract from these 'blood' spots can be used instead of serum samples for measles laboratory diagnosis or investigations. Measles antibody detection is readily carried out by ELISA on serum samples. The same technique can be used on eluates from capillary blood spots. Measles antibody titres determined on matched serum and blood spot samples from 27 children were compared. A strong correlation was found between the results obtained with the two methods of blood sampling.

Vascular adhesion molecules and immunogenicity in blood vessels used as coronary artery bypass grafts

OBJECTIVE

The performance of coronary bypass grafts can be affected by a variety of circulating cell types. The initial event in any biological effect of such cells is adherence to the vascular endothelium prior to migration into the perivascular space. We aimed to investigate the expression of molecules that regulate cell adhesion in blood vessels employed as bypass conduits.

METHODS

Segments of human saphenous vein, internal mammary artery, gastroepiploic artery and inferior epigastric artery were stained using specific monoclonal antibodies against the endothelial workers EN-4, Pal-E, von Willebrand factor small (vWF), and the cell adhesion molecules platelet-endothelium cell adhesion molecule (PECAM), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin, the leucocyte marker (CD45) and major histocompatibility complex (MHC) class I and II antigens, with visualisation by ABC immunoperoxidase method.

RESULTS

All vessels had a strong expression of the endothelial specific antigens EN4, vWF, and PECAM as well as MHC class I. However, there was less expression of Pal-E, ICAM-1, E-Selectin and of the DR determinant of MHC class II. VCAM-1, DP and DQ determinants of MHC class II were expressed to a weaker extent. There were no marked differences in the expression of all the molecules examined between the four vessel types.

CONCLUSION

Thus vessels used as bypass grafts are immunogenic and possess the potential to attract and interact with blood elements. Definition of the molecules responsible could offer opportunities for modulating the response to such interactions.

Effects of cryopreservation upon vein function in vivo

This review covers experimental and clinical experiences with transplantation of allogeneic veins processed by slow rate cooling with 2.5% (W/V) chondroitin sulfate and 1 M dimethylsulfoxide. These results are contrasted with the results obtained using dimethylsulfoxide alone. The short-term patency of experimental autologous (100%) and allogeneic (70-100%) cryopreserved veins may be attributed to the combination of "no-touch" procurement techniques employing the smooth muscle relaxant papaverine, the chondroitin sulfate preservation method, and recipient therapy. Explanted autografts retain many cell and tissue functions. In contrast, explanted allografts demonstrate short-term loss of endothelial cells and smooth muscle function, both of which subsequently return. Clinically there have been positive short-term correlations between good initial runoff from the graft site and 1-year patency (68-74%) and limb salvage (94%) rates. In contrast, grafts with poor initial runoff, composite grafts, or grafts requiring secondary reconstruction resulted in lower 1-year patency (40-44%) and limb salvage (64%) rates. More experience, larger study groups, and longer follow-up are necessary to evaluate the clinical performance of chondroitin sulfate-preserved grafts. In the meantime, chondroitin sulfate-preserved veins are reserved for coronary artery bypass or peripheral bypass patients in the absence of suitable autologous vessels.

[The demonstration by immunofluorescence of inframicrobial antigens on samples of peripheral blood vessels (artery and vein) from subjects with different vascular diseases]

The presence of fourteen inframicrobial agents was investigated by the immunofluorescence technique using specific antisera on 345 samples of arteries and veins collected during operation from patients with chronic vascular diseases (arteritis, varicosity) and on 50 samples of umbilical cord. Results indicated a positivity rate of 75.45%; most of the cases had associations of two to five antigens. Coxsackie A virus and mycoplasmas were the agents most frequently found.

Demonstration of interleukin-1 beta on perifollicular endothelial cells in the thyroid glands of patients with Graves' disease

We examined the presence of interleukin-1 (IL-1) in the thyroid glands of 20 patients with Graves' disease and 10 control subjects, using anti-IL-1 monoclonal antibodies in conjunction with immunohistochemical techniques. In 13 (65%) Graves' disease patients, IL-1 beta, but not IL-1 alpha, was demonstrated on the capillary endothelial cells (EC) around follicles (perifollicular EC). However, the EC of arteries and veins were negative for both IL-1 beta and IL-1 alpha. In the control group, none of the thyroid glands showed positive staining for IL-1 beta or IL-1 alpha. There was a significant correlation (P less than 0.025) between the presence of IL-1 beta on perifollicular EC and the presence of serum antimicrosomal antibodies. These results provide an important insight into the involvement of IL-1 beta in the development of Graves' disease.

Lymphaticovenous differentiation in Kaposi's sarcoma. Cellular phenotypes by stage

The histogenesis of Kaposi's sarcoma was investigated by immunohistochemical staining of 20 skin specimens that represented four main histologic stages. The early phase of Stage 1 contained lymphatic-like clefts lined by endothelial cells with thin, discontinuous basement membranes shown by anti-laminin, absent Factor VIII-related antigen reactivity (FVIIIRAg), and only rare staining with dilute Ulex europaeus agglutinin I (UEA-I). In the late phase of Stage 1, the clefts developed into anastomosing, blood-filled channels, and the basement membrane became complete. Endothelial marker reactivities were not definitive, but weak staining with UEA-I and variable staining for FVIIIRAg characterized the spindle cells of Stage 2. However, spindle cells in monomorphic nodules were individually enclosed by immunoreactive laminin. The sequence of events, particularly in light of previous angiographic findings of lymphaticovenous union, suggests a disturbance in lymphaticovenous differentiation in Kaposi's sarcoma. Sclerotic closure of channels unable to maintain competent blood flow may select against lymphendothelial traits in the developing spindle cell nodule.

Induction of an activation antigen on postcapillary venular endothelium in human skin organ culture

We studied the effects of the immune mediators interleukin 1, interleukin 2, tumor necrosis factor, immune interferon, and lipopolysaccharide on the expression of the endothelial activation antigen recognized by the murine monoclonal antibody H4/18 in short term organ cultures of newborn foreskins. No endothelial staining was detectable before culture. Interleukin 1, tumor necrosis factor, and lipopolysaccharide each induced 2+ to 3+ H4/18 staining of microvascular endothelium at 6 hr. Combining mediators produced additive (3+ to 4+) effects, and reactivity was lost or markedly diminished by 24 hr. Incubation with culture medium alone resulted in 1+ to 2+ H4/18 staining at 6 hr, and medium conditioned by cultured foreskins, but not mock-conditioned medium, could induce H4/18 binding in cultured human umbilical vein endothelial cells. The spontaneous expression of microvascular staining in the foreskins was markedly inhibited by cyclosporin A, but not polymyxin B sulfate or dexamethasone; cyclosporin A did not inhibit induction of staining by exogenous mediators. Both light level and immunoultrastructural studies demonstrated H4/18 expression to be associated predominantly with postcapillary venular endothelial cells of the superficial vascular plexus. We conclude that microvascular endothelium of skin can undergo activation in response to exogenous and endogenous cytokines, with the greatest changes occurring in those portions of the vessels most involved in leukocyte and lymphocyte trafficking.

Expression of I-region-associated antigen (Ia) and interleukin 1 by subcultured human endothelial cells

Activation of T cells requires three signals from an antigen-presenting cell: antigen, Ia determinants (HLA-D region determinants in man), and interleukin 1 (IL-1). Recent evidence has suggested that macrophages, dendritic cells, epidermal Langerhan's cells, and endothelial cells can each function as antigen-presenting cells (APC). If these cell types can independently function as APC, they should synthesize Ia determinants and secrete IL-1. To determine if endothelial cells fulfill these requirements, we have propagated human umbilical vein endothelial cells by serial subculture for extended periods of time and assessed Ia expression and IL-1 secretion. The endothelial cells were subcultured for 8 months (approximately 20 subcultures) and were found to display classic morphology and immunofluorescent staining for the endothelial cell-specific marker Factor VIII-related antigen. In a separate paper we have shown that these subcultured endothelial cells can present antigen to T cells in a HLA-D region-restricted fashion (C. R. Wagner, R. M. Vetto, and D. R. Burger, Subcultured human endothelial cells can independently function as fully competent antigen-presenting cells, accepted for publication, Hum. Immunol.). In this paper we present evidence demonstrating that extensively subcultured endothelial cells biosynthesize both HLA-DR and HLA-DS molecules after exposure to T cells and antigen or to a supernatant from antigen-activated T cells. Evidence is also presented that when endothelial cells are cultured in the presence of lipopolysaccharide they secrete a molecule(s) with IL-1 activity as assayed by LBRM-33-IA5 cell line production of interleukin 2.

Immunological characterisation of plasminogen activators in the human vessel wall

A histochemical technique was used to identify the activity of the plasminogen activator (PA) in the vessel wall of veins. Antibodies against melanoma cell activator and urokinase (UK), both raised in goats, were mixed into the fibrin film. The PA activity was quenched by the antibodies against melanoma activator but remained unchanged when antibodies against UK, or an IgG preparation of normal goat serum, was mixed in the fibrin film. The results of this study show that the PA activity in the vein vessel wall is immunologically similar to or identical to the PA derived from melanoma cells which has previously been shown to cross-react with the tissue-like PA. No UK-like activity was present in the vessel wall.

Cellular cytotoxicity against canine endothelial cells. Analysis of determinants recognized by CTL

A method is described which permits culture of both arterial and venous canine endothelial cells. Cell-mediated cytotoxicity against cultured endothelial cells has been studied. A 51Cr-release assay was used to detect CTL generated in MLC. Both arterial and venous endothelial cells are lysed by CTL specifically. Cold target inhibition experiments have been performed to analyse the CTL-recognized antigens on arterial and venous endothelial cells. Different antigens are recognized by CTL on venous endothelial cells and PHA-blasts; it is possible that CTL recognize venous endothelial cells through class II antigens or E-M antigens. Arterial endothelial cells and PHA-blasts share CTL-recognized antigens.

[Ability of isoelectric focusing to separate antitetanus antibodies in venous blood]

In a previous study, we have showed a great heterogeneity of antitetanus antibodies using polyacrylamide thin layer isoelectrofocusing. In this study, we have improved the resolution of the focused antitetanus antibodies by electrofocusing in sucrose density gradients, which is a suitable procedure for preparative work. After isoelectrofocusing the elution is performed according to any pH variation. For each fraction, we have determined pH, absorbance at 280 nm, protein level by method of Lowry, IgG concentration using immunonephelometric method and antitetanus antibodies concentration by radioimmunoassay. Furthermore, the purity of each fraction is verified by polyacrylamide slab gel isoelectrofocusing. It is concluded that the isoelectric point of antitetanus antibodies is alkaline range between 7.5 and 8.5. This precise knowledge could afford an opportunity for the industrial preparation of antitetanus antibodies.

Antigenicity of venous allografts

With isolated exceptions, the clinical use of venous allografts has been disappointing. Considerable evidence indicates that allograft antigenicity plays a major role in the failure of venous allografts when used as arterial replacements. Recent reports suggest that DMSO-cryopreservation of venous allografts may reduce allograft antigenicity while preserving allograft viability. The present study examines the effect of modifications of vein allografts on subsequent allograft antigenicity. Skin grafts were transplanted from ACI to Lewis inbred strains of male rats. Primary skin graft rejection occurred in 9.0 +/- 1.0 days. Subcutaneous implantation of fresh inferior vena cava from ACI rate into Lewis rats resulted in subsequent skin graft rejection in 5.0 +/- 1.0 days, confirming the antigenicity of venous tissue. Cryopreservation of ACI inferior vena cava for seven days prior to implantation, with or without 15% DMSO, resulted in subsequent skin graft rejection in 5.0 +/- 1.0 days. Treatment of ACI inferior vena cava with 0.30% gluteraldehyde for 20 minutes prior to implantation in Lewis rats resulted in skin graft rejection in 9.0 +/- 1.0 days, the same time as a first set rejection. This study indicates that unmodified veins are normally antigenic and that this antigenicity is not eliminated by cryopreservation with or without DMSO. Gluteraldehyde treatment appears to reduce allograft antigenicity, but results in a nonviable graft. At the present time, there is no known way to reduce the antigenicity of viable venous allografts.

Comparison of the immunologic reactions of arterial transplants in the arterial system and of venous transplants in the venous system using inbred strains of rats

(1) Arterial transplants used as arterial replacements induce sensitization of the recipient in the weakly as well as in the strongly allogeneic systems (afferent limb). (2) Venous transplants used as venous replacements induce sensitization of the recipient (afferent limb). (3) Arterial transplants show increasingly severe rejection reactions paralleling the degree of immunogenetic difference (efferent limb). (4) Veins transplanted as venous replacements are tolerated even in the strongly allogeneic systems (efferent limb).

IgG in the walls of the post-capillary venules of mouse lymphatic tissue

IgG was demonstrated in the endothelium of the post-capillary venules of the axillary and abdominal lymph nodes as well as of the Peyer's patches in DBA/2 mice by using a direct immunoperoxidase technique. The significance of this IgG in the regulation of T-lymphocyte passage through the endothelium of the post-capillary venules was discussed.

Endothelium-associated IgG in the post-capillary venules of the lymphatic tissues in mice bearing experimental neoplasia

Post-capillary venules (PVC) of the lymph nodes and Peyer's patches were studied in frozen sections stained with an indirect immunoperoxidase technique to demonstrate their endothelium-associated IgG in DBA/2 mice bearing mastocytoma. The previously established three types of IgG-distribution (luminal, intraendothelial and basement membrane site), each confined to one of the three PCV grades (graded on the basis of the endothelial cell height), were found in these tumor-bearing mice, too. This finding shows that the tool applied in T-lymphocyte deprivation, be it a tumor or anti-theta-globulin, does not influence the behavior of this IgG-distribution profile. This fact lends further support to the thesis that the endothelium-associated IgG could be involved in the regulation of the T-cell passage through the wall of the post-capillary venules.

Paracortical post-capillary venules of human lymph nodes with special reference to the distribution of their endothelial IgG

The distribution of IgG in the endothelium of the paracortical post-capillary venules (PCV) of human lymph nodes was studied in frozen sections by using an indirect immunoperoxidase technique. Three different patterns of distribution could be differentiated (luminal site, intraendothelial and basement membrane site). Each of these patterns was characteristically encoutered in association with one of three grades of PCV (graded on the basis of the height of their endothelial cells). The significance of this close relationship between the IgG distribution and the changes in PCV endothelium was discussed in regard to the T-lymphocyte recirculation. A hypothesis was introduced describing the possible sequence of events involved in the traversing of T-lymphocyte through the PCV endothelium.

[Comparative immunological and morphological studies following transplantation of fresh and preserved allogeneic vein and artery segments in rat experiments]

Immunological and morphological investigations were carried out on immunogenetically different strain combinations of inbred rats following transplantation of fresh allogeneic and implantation of formalin preserved vein segments. In contrast to vital allogeneic transplants, which evoke an immunological response depending on immunogenetic difference between donor and recipient, there is neither humoral nor cellular immunological response after implantation of formalin fixed vein segments. Therefore, from an immunological standpoint, strongly allogeneic vein implants preserved by formalin can be used for replacement of arteries.

IgG in the walls of the post-capillary venules of human lymph nodes

IgG immunoglobulin was demonstrated in the wall of the post-capillary venules of human para-aortal lymph nodes by using a direct immunoperoxidase technique. The relationship of this immunoglobulin to the recirculation of the small lymphocytes is discussed.

Immunological studies with aortic and venous tissue antigens. III. Examination of cell-mediated and humoral immune response induced by human vascular antigens

The effects of human vascular antigens on the cell-mediated and the humoral immune response were studied in guinea pigs. In animals immunized with buffer extracts of aortic and venous wall a well measurable cell-mediated and humoral immune response were developed. Between the two kinds of vascular extracts in the skin tests, migration inhibition tests and antibody-production tests a cross-reactivity was observed, whereas the induction of desoxyribonucleic acid-synthesis proved to be specific. No cellular or humoral immune response to vascular extracts was detectable in the control animals. Analysing the time-kinetics of the cell-mediated and humoral immune response it was found, that with the increased production of antibodies the cellular immune reactions did not cease until the ninth week.

Immunological studies with aortic and venous tissue antigens. I. The antigen structure of vascular tissues

Fractionation of intact and arteriosclerotic aortic and venous intimas was performed. The distribution of the obtained fractions (CTC, CSC, collagen, SGP and elastin), their disc-electrophoretic and immunological behaviour was studied. With the process of arteriosclerosis a decrease of the structural proteins (collagen, SGP, elastin) and an increase in the amount of some proteins of plasmatic origin could be demonstrated. By the use of absorbed immune sera in the immunoelectrophoretic patterns of aortic and venous CTC-extracts two vessel wall specific arcs were found.

Immunological studies with aortic and venous tissue antigens. II. Antibodies to vascular antigens

In the sera of patients with different clinical manifestations of arteriosclerosis antibodies were demonstrated against the CTC-extract in about 50 p. 100 of the cases. Using venous CTC-extracts positive results were obtained in patients with phlebothrombosis in 70 p. 100 of the cases. Cross reactions between the aortic and venous tissues were not detected.

Properties of canine tissue thromboplastins from brain, lung, arteries, and veins

Properties of the protein moieties of canine tissue thromboplastins (TTP's) from brain (BTTP), lung (LTTP), arteries (ATTP), AND VEINS (VTTP) were determined. The maximum specific activity of each protein moiety after its relipidation was obtained when the phospholipid-delipidated TTP ratio was 0.32 and was 1,395 U/mg BTTP, 1,130 U/mg LTTP, 630 U/mg VTTP, and 435 U/mg ATTP. The amino acid contents of the protein moieties of LTTP, ATTP, and VTTP were closely similar, but that of BTTP was significantly different. The Ouchterlony analysis showed that BTTP did not react at all with the antibody against VTTP, but that three other TTP's did and showed the reaction of complete identity. Then, the reactivity of 125-I-labeled TTP's with the anti-VTTP antibody was studied. The results showed that 0.79 +/- 0.01 (SD) % of [125I]BTTP, 10.24 +/- 0.5 (SD) % of [125I]LTTP, 19.4 +/- 0.2 (SD) % of [125I]VTTP, and 5.88 +/- 0.4 (SD) % of [125I]ATTP added were bound to the antibody in 2 h. Next, the molecular weight of each was determined by Sephadex G-200 filtration, which averaged 80,000 +/- 4,000 (SD) ([125I]BTTP), 113,000 +/- 5,000 (SD) ([125I]LTTP), 62,000 +/- 3,000 (SD) ([125I]ATTP), and 47,000 +/- 2,000 (SD) ([125I]VTTP). Finally, the plasma behavior of each was studied in four dogs. The plasma half-life averaged 8.1 +/- 0.24 (SD) h ([125I]BTTP), 14.6 +/- 0.5 (SD) h ([125I]LTTP), 7.38 +/- 0.48 (SD) h ([1252]ATTP), and 24.3 +/- 0.9 (SD) h ([125I]VTTP). These results indicate that the protein moieties of canine TTP's from brain, lung, arteries, and veins are closely similar in some aspects but dissimilar in others and are definitely not identical.