Factors influencing human leukocyte adherence in vitro

Studies were performed on factors influencing leucocyte adherence in vitro. Blood condensation was found to increase leukocyte adherence. Addition of heparin, dextran or ethanol caused a significant reduction of white blood cell count in blood samples in comparison with blood mixed with sodium EDTA or ACD solution. This suggests the existence of two granulocyte subpopulations; viz, rapidly adhering and slowly adhering. Heparin enhanced granulocyte adherence, while dextran and ethanol decreased it. Five-day storage of ACD blood led to a decrease in granulocyte adherence, while addition of heparin or histamine to ACD blood prevented this change to occur. The glucose concentration of 1,000 mg/dl augmented granulocyte adherence, while higher glucose concentrations induced its progressive fall below the control values. There was no significant change of lymphocyte adherence during the experiments.     

Factors influencing adherence of Candida spp. to host tissues and plastic surfaces

Attachment of Candida spp. to host tissues and plastic surfaces is the first and a crucial step that initiates colonization by yeast cells and subsequent development of disseminated fungal infection. These infections are associated with high degree of morbidity, mortality and extra cost. Modern trends have focused not only on how best to treat but also on how to prevent Candida infections. To achieve this goal, the factors that influence the adherence of Candida spp. to biological and non biological surfaces have been studied. C. albicans adheres at a degree higher than that of the other Candida spp. and C. tropicalis adheres to a lesser extent. This may reflect the higher pathogenicity of C. albicans compared to the other Candida spp. Germinated C. albicans cells adhere to host tissue more readily than do yeast-phase. Sugars play an important role in the adherence of Candida spp. Overall, galactose was found to promote the adherence of Candida spp. to host tissues and plastic surfaces more than any other mono or disaccharide. Amino sugars on the other hand inhibit the adherence of the yeast cells. Divalent ions such as Ca2+ and Mg2+ promote the adherence of Candida spp. more than monovalent ions. Candida spp. express on their surface receptors, which interact with a wide variety of host proteins including fibrinogen, fibronectin, lamanin, and type I and IV collagen thus binding Candida spp. To glycoproteinaceous conditioning film at the blood-polymer interface. Coaggregation of Candida spp. with other bacteria promotes colonization of yeast cells to oral biofilm, host tissues, and to surfaces of the indwelling vascular catheters. These factors form the basis for the interference with the adherence of Candida spp.     

Regulation of leukocyte glass adherence and tube leukocyte adherence inhibition (LAI) reactivity by serum factors in dogs with progressing or spontaneously regressing canine transmissible venereal sarcoma (CTVS)

Summary We examined the regulation of leukocyte glass adherence and tube leukocyte adherence inhibition (LAI) reactivity by serum factors in dogs with regressing or progressing canine transmissible venereal sarcomas (CTVS). Both regressor and progressor peripheral blood leukocytes (PBL), draining and nondraining lymph node cells (LNC), and splenic leukocytes were significantly responsive to CTVS antigen extract in tube LAI. In contrast, a significant decrease in basal glass adherence of progressor PBL, draining and nondraining LNC, and splenic leukocytes was observed. Normal glass adherence was restored to progressor leukocytes by extensive washing with warm serum-free media, while significant tube LAI responsiveness to CTVS antigen extract was maintained. Preincubation of regressor PBL and LNC with progressor sera in two-stage tube LAI decreased the basal glass adherence of treated leukocytes. This effect of progressor sera was heat labile, a characteristic of CTVS antigen. Collectively, these findings suggest that progessor leukocytes and progressor sera treated regressor leukocytes were activated by interaction with serum CTVS antigen and thus behaved in tube LAI as stimulated cells, even in the absence of CTVS antigen. Regressor but not progressor sera were shown to contain anti-CTVS IgG with specific arming activity for normal dog PBL, but not LNC in two-stage tube LAI. The nonadherent response of peripheral blood neutrophils in two-stage tube LAI was proportional to the concentration of arming IgG, whereas no change was observed in glass adherence of PBL. The results of this study define the role of progressor and regressor serum factors in the mechanism of tube LAI and demonstrate a relationship between leukocyte glass adherence and the clinical course of CTVS. These findings show that tube LAI is a simple and reproducible measure of active factors in the immune response to a tumor.This investigation was supported in part by grant, CA-23469, from the National Cancer Institute, DHHS, and is submitted as Scientific Contribution No. 1051, Storrs Agricultural Experiment Station, University of Connecticut, Storrs, CT 06268 USA     

Involvement of Minerals in Adherence of Legionella pneumophila to Surfaces

Legionella pneumophila is the causative agent of 90 % of Legionnaires’ disease cases. This bacterium lives naturally in fresh water and can colonize biofilms, which play an important role in the protection of Legionella against environmental stress factors. Relationship between the presence of minerals in water and Legionella adherence to surfaces is not well-known. In this study, we studied influence of minerals on bacterial adherence. For the first time, to our knowledge, this report shows that calcium and magnesium in a less extent, enhances the adherence of Legionella to surfaces compared to the bacteria behavior in distilled water. Treatment with proteinase K of live cells showed that surface proteins do not seem to play a crucial role in bacteria adherence to surfaces. Our results represent a first step in understanding effect of ions on Legionella adherence to surfaces. Such field of research could be helpful to better understand biofilm colonization by this bacterium to improve Legionella risk management in water networks.     

Determinants of Medication Adherence to Antihypertensive Medications among a Chinese Population Using Morisky Medication Adherence Scale

Background and Objectives

Poor adherence to medications is one of the major public health challenges. Only one-third of the population reported successful control of blood pressure, mostly caused by poor drug adherence. However, there are relatively few reports studying the adherence levels and their associated factors among Chinese patients. This study aimed to study the adherence profiles and the factors associated with antihypertensive drug adherence among Chinese patients.

Methods

A cross-sectional study was conducted in an outpatient clinic located in the New Territories Region of Hong Kong. Adult patients who were currently taking at least one antihypertensive drug were invited to complete a self-administered questionnaire, consisting of basic socio-demographic profile, self-perceived health status, and self-reported medication adherence. The outcome measure was the Morisky Medication Adherence Scale (MMAS-8). Good adherence was defined as MMAS scores greater than 6 points (out of a total score of 8 points).

Results

From 1114 patients, 725 (65.1%) had good adherence to antihypertensive agents. Binary logistic regression analysis was conducted. Younger age, shorter duration of antihypertensive agents used, job status being employed, and poor or very poor self-perceived health status were negatively associated with drug adherence.

Conclusion

This study reported a high proportion of poor medication adherence among hypertensive subjects. Patients with factors associated with poor adherence should be more closely monitored to optimize their drug taking behavior.     

Predictors of Adherence to Multiple Clinical Preventive Recommendations among Adults with Diabetes in Spain

ObjectiveThis study aims to describe adherence to seven clinical preventive services among Spanish adults with diabetes, to compare adherence with people without diabetes and to identify predictor of adherence to multiple practices among adults with diabetes.DesignCross-sectional study based on data obtained from the European Health Survey for Spain 2009 and the Spanish National Health Survey 2011. We analyzed those aged 40-69 years (n= 20,948). Diabetes status was self-reported. The study variables included adherence to blood pressure (BP) checkup, cholesterol measurement, influenza vaccination, dental examination, fecal occult blood test (FOBT), mammography and cytology. Independent variables included socio-demographic characteristics, variables related to health status and lifestyle factors.ResultsThe study sample included 1,647 subjects with diabetes and 19,301 without. Over 90% had measured their BP and cholesterol in the last year, 44.4% received influenza immunization, 36.4% had a dental checkup within the year and only 8.1% underwent a FOBT. Among diabetic women 75.4% had received a mammography and 52.4% a cytology in the recommended periods. The adherence to BP and cholesterol measurements and influenza vaccination was significantly higher among those suffering diabetes and cytology and dental checkup were lower. Only 63.4% of people with diabetes had fulfilled half or more of the recommended practices. Female sex, higher educational level, being married or cohabiting, higher number of chronic conditions and number of physician visits increased the adherence to multiple preventive practices. For each unhealthy lifestyle reported the probability of having a higher adherence level decreased.ConclusionsAcceptable adherence is found for BP and cholesterol checkups and mammography. Unacceptably low rates were found for influenza vaccine, dental care, cytology and FOBT. Moreover, preventive services are provided neither equitably nor efficiently so future research needs to identify individual and organizational factors that allow interventions to reach these subjects with diabetes.     

Prevention of biofilm formation by polymer modification

Bacterial biofilm formation on synthetic polymers plays an important role in industry and in modern medicine, leading, for example, to difficult-to-treat infections caused by colonized foreign bodies. Prevention of biofilm formation is a necessary step in the successful prophylaxis of such infections. One approach is to inhibit bacterial adherence by polymer surface modification. We have investigated polymer modification by glow discharge treatment in order to study the influence of the modified surface on bacterial adherence. Surface roughness, surface charge density and contact angles of the modified polymers were determined and related to the adherence ofStaphylococcus epidermidis KH6. Although no influence of surface roughness and charge density on bacterial adherence was noticed, a correlation between the free enthalpy of adhesion (estimated from contact angle measurements) and adherence was observed. There seems to exist a certain minimum bacterial adherence, independent of the nature of the polymer surface. Modified polymers with negative surface charge allow for bacterial adherence close to the adherence minimum. These polymers could be improved further by the ionic bonding of silver ions to the surface. Such antimicrobial polymers are able to prevent bacterial colonization, which is a prerequisite for biofilm formation. It is suggested that modification of polymers and subsequent surface coupling of antimicrobials might be an effective approach for the prevention of bacterial biofilm formation.     

Adherence induces selective mRNA expression of monocyte mediators and proto-oncogenes

Adherence is an important regulatory signal for several monokines and the proto-oncogenes c-fms and c-fos in human peripheral blood monocytes. Although there is little if any constitutive expression of the IL-1 beta, TNF-alpha and CSF-1 genes in freshly isolated monocytes, adherence is sufficient to induce high steady-state levels of mRNA for TNF and c-fos and more slowly that of CSF-1. Expression of mRNA for the CSF-1R gene, c-fms, was transiently down-regulated by 4 h. In contrast, the induction of high levels of IL-1 beta mRNA were achieved independent of culture conditions. Although all of these genes could be induced by adherence, actual secretion of the mediators required the exposure to a second signal derived from LPS. Thus adherence rapidly primes monocytes for a variety of inflammatory responses, the magnitude of which depends on the nature of a second "activating" signal. It is likely that some of these products act locally as paracrine or autocrine factors to further regulate the phenotype of the differentiating macrophage.     

Factors Influencing Antiretroviral Adherence and Virological Outcomes in People Living with HIV in the Highlands of Papua New Guinea

Adherence to antiretroviral therapy (ART) is paramount for virological suppression and positive treatment outcomes. ART has been rapidly scaled up in Papua New Guinea (PNG) in recent years, however clinical monitoring of HIV+ individuals on ART is limited. A cross-sectional study was conducted at two major sexual health clinics in high HIV prevalence provinces in the Highlands Region of PNG to assess ART adherence, factors affecting adherence and the relationship between ART adherence and virological outcomes. Ninety-five HIV+ individuals were recruited and administered a questionnaire to gather demographic and ART adherence information whilst clinical data and pill counts were extracted from patient charts and blood was collected for viral load testing. Bivariate analysis was performed to identify independent predictors of ART adherence. Fourteen percent (n = 12) of participants showed evidence of virological failure. Although the majority of participants self-reported excellent ART adherence in the last seven days (78.9%, 75/91), pill count measurements indicated only 40% (34/84) with >95% adherence in the last month. Taking other medications while on ART (p = 0.01) and taking ART for ≥1 year (p = 0.037) were positively associated with adherence by self-report and pill count, respectively. Participants who had never heard of drug resistance were more likely to show virological failure (p = 0.033). Misconception on routes of HIV transmission still persists in the studied population. These findings indicate that non-adherence to ART is high in this region of PNG and continued education and strategies to improve adherence are required to ensure the efficacy of ART and prevent HIV drug resistance.     

Lymphocyte-fibroblast adhesion induced by interferon-gamma

Adhesion of lymphocytes to vascular endothelium is thought to be of importance in regulating the passage of lymphocytes from the circulation to areas of inflammation. Evidence suggests the presence of site-specific lymphocyte receptor molecules on the endothelial cell surface which can be modulated by soluble immune factors. The factors responsible for maintaining lymphocyte infiltration at tissue sites are unknown. We have examined the adherence of human peripheral blood T lymphocytes to human fibroblast monolayers in vitro and the role of interferon-gamma in enhancing adherence. Treatment of fibroblasts with interferon-gamma resulted in an increase in the number of adherent T cells in a dose- and time-dependent manner. Enhanced adhesion was noted as early as 4 hr after interferon stimulation (291 +/- 7 T cells/field vs 51 +/- 10 without IFN stimulation) and binding was further increased by lengthening the exposure time of fibroblasts to interferon up to 72 hr (475 +/- 86 T cells/field). Kinetic and inhibition experiments using monoclonal antibody to HLA-DR demonstrated that adhesion of T lymphocytes to interferon-stimulated fibroblasts proceeds by a mechanism independent of DR induction. In addition, adherence was not histocompatibility antigen-restricted, as adherence to autologous and allogeneic fibroblast monolayers was not significantly different. Nonadherent T cells, collected at the end of adhesion assays, were deficient in their capacity to bind to a second interferon-treated monolayer, suggesting the depletion of a subpopulation of T cells responsible for adhesion. Alterations of fibroblasts in vivo by immune cell-derived cytokines may be an important mechanism for the localization of lymphocytes at sites of connective tissue inflammation.     

Characterization of an outer membrane protein associated with haemagglutination and adhesive properties of enteroaggregative Escherichia coli O111:H12

Diarrhoeagenic Escherichia coli strains of serotype O111:H12 are characterized by their aggregative pattern of adherence on cultured epithelial cells and thus are considered enteroaggregative E. coli (EAEC). We have previously shown that these EAEC strains lack the genes encoding the aggregative fimbriae I and II described in other heterologous EAEC strains. In this paper, we show compelling data suggesting that a plasmid-encoded outer membrane 58 kDa protein termed aggregative protein 58 (Ap58) produced by EAEC O111:H12 strains, is associated with the adherence capabilities and haemagglutination of animal red blood cells. This conclusion is supported by several lines of evidence: (i) adherent O111:H12 strains are able to produce Ap58; (ii) non-adherent O111:H12 strains are unable to produce Ap58; (iii) antibodies raised against Ap58 inhibited adherence and haemagglutination of epithelial and bovine red blood cells, respectively; (iv) a non-adherent E. coli K-12 host strain containing the ap58 gene determinant on plasmid pVM15 displayed abundant adherence to cultured HEp-2 cells; and (v) the purified Ap58 bound specifically to HEp-2 and bovine red blood cells. Our findings indicate that the aggregative adherence in the O111:H12 strains may be also mediated by non-fimbrial adhesins. We believe our data contribute to the understanding of the adherence mechanisms of these organisms.     

Effect of anticoagulation with citrate versus heparin on the adsorption of coagulation factors to blood purification resins with different charge

In liver failure, hydrophobic toxins accumulate in the blood circulation. To support hepatic function, extracorporeal blood purification systems have been developed, in which both cationic and neutral adsorbents are used to remove albumin-bound metabolites from blood. An issue of these systems is the additional removal of coagulation factors containing negatively charged γ-carboxyglutamate (Gla) domains, which, in physiological conditions, are shielded by calcium ions. We hypothesized that complexation of calcium ions by citrate leads to exposure of negative Gla domains, resulting in their binding to the positively charged adsorbents. The data presented here confirm that the binding of coagulation factors containing Gla domains to positively charged polymers is enhanced in the presence of citrate as compared to heparin. This effect increased with increasing charge density of the polymer and has important implications for the clinical application of positively charged polymers.     

Medication adherence in type 2 diabetes: the ENTRED study 2007, a French Population-Based Study

Background

Adherence to prescribed medications is a key dimension of healthcare quality. The aim of this large population-based study was to evaluate self-reported medication adherence and to identify factors linked with poor adherence in patients with type 2 diabetes in France.

Methodology

The ENTRED study 2007, a French national survey of people treated for diabetes, was based on a representative sample of patients who claimed reimbursement for oral hypoglycaemic agents and/or insulin at least three times between August 2006 and July 2007, and who were randomly selected from the database of the two main National Health Insurance Systems. Medication adherence was determined using a six-item self-administered questionnaire. A multinomial polychotomous logistic regression model was used to identify factors associated with medication adherence in the 3,637 persons with type 2 diabetes.

Principal Findings

Thirty nine percent of patients reported good medication adherence, 49% medium adherence and 12% poor adherence. The factors significantly associated with poor adherence in multivariate analysis were socio-demographic factors: age <45 years, non-European geographical origin, financial difficulties and being professionally active; disease and therapy-related factors: HbA_1c>8% and existing diabetes complications; and health care-related factors: difficulties for taking medication alone, decision making by the patient only, poor acceptability of medical recommendations, lack of family or social support, need for information on treatment, reporting no confidence in the future, need for medical support and follow-up by a specialist physician.

Conclusions

In a country with a high level of access to healthcare, our study demonstrated a substantial low level of medication adherence in type 2 diabetic patients. Better identification of those with poor adherence and individualised suitable recommendations remain essential for better healthcare management.     

Mechanism of cigarette smoke condensate induced adhesion of human monocytes to cultured endothelial cells

Cigarette smoking is ranked among the leading risk factors in the etiology of atherosclerotic vascular disease. The mechanisms, however, that link cigarette smoking to increased incidence of atherosclerosis are not understood. The adherence of circulating monocytes to the endothelium, migration into the subendothelium, and subsequent formation of foam cells are principal initial events in the development of atherosclerosis. We therefore determined whether cigarette smoke caused increased adherence of monocytes to endothelial cells and the cellular mechanism of this increased adherence. Cigrette smoke condensate (CSC), the particulate fraction of cigarette smoke derived from 2R1 standard research cigarettes, at a concentration of 25–30 μg/ml (average yield of CSC is 26.1 mg/cigarette), augmented (70–90%) basal adherence of human peripheral blood monocytes to a cultured monolayer of endothelial cells derived from bovine aorta (BAEC) and human umbilical vein (HUVEC). There was a concomitant increase in the expression of CD11b ligand on the surface of monocytes as determined by flow cytometry, utilizing FITC conjugated Mab MO-1 (CD11b). However, nicotine (1–15 μg/ml) and cadmium sulfate (10 μg/ml), constituents of CSC, individually or in combination had no effect either on CD11b expression or adherence of monocytes to endothelial cells. Treatment of HUVEC with CSC for 60 min also resulted in an increased expression of ICAM-1 and ELAM-1 as determined by mean fluorescence intensity of ICAM-1 and ELAM-1 labeled cells in flow cytometric analysis. The CSC induced expression of CD11b in monocytes was optimal at 25–30 min and was inhibited by protein kinase C inhibitors, staurosporine and H-7, and also by baicalein, a lipoxygenase inhibitor. Similarly, CSC induced ICAM-1 and ELAM-1 expression in HUVEC was inhibited by protein kinase C inhibitors. CSC stimulated the adherence of human monocytes but not the monocytic cell lines HL-60, U937, and THP-1 to endothelial cells. The CSC stimulated adherence of human monocytes was inhibited (80%) by MAb to CD11b and 50% by Mab to ICAM-1 and ELAM-1. These results suggest that cigarettee smoke particulate constituents activate protein kinase C, leading to increased surface expression of adhesive ligand CD11b on peripheral blood monocytes and counter receptor(s) ICAM-1 and ELAM-1 in endothelial cells. The expression of ligand and counter receptor leads to potentiated adherence of monocytes to endothelial cells, an initial event in the pathogenesis of cigarette smoke induced inflammatory response in the vessel wall. © 1994 Wiley-Liss, Inc.     

Adherence influencing factors in patients taking oral anticancer agents: A systematic review

BackgroundThe use of oral anticancer agents increased steadily in the last decades. Although oral anticancer agent adherence is important for a successful treatment, many patients are insufficiently adherent.PurposeTo evaluate adherence influencing factors in patients taking oral anticancer agents.MethodsA systematic literature search was performed in Medline and Embase. Titles and abstracts and in case of relevance, full-texts were screened according to predefined inclusion criteria. The risk of bias was assessed. Both were carried out independently by two reviewers. Relevant data on study characteristics and results were extracted in standardized tables by one reviewer and checked by a second. A meta-analysis was not performed because of clinical and methodological heterogeneity between the studies to avoid misleading results. Data were synthesized in narrative way using a standardized procedure.ResultsTwenty-two relevant studies were identified. The study quality was moderate. Especially the risk of bias regarding the measurement of influencing factors and adherence was mostly unclear. Social support, intake of aromatase inhibitors, and lower out-of-pocket costs for OACA seem to have a positive effect on adherence. Depression and the number of different medications seem to have a negative effect on adherence.Low age and very high age seem to be associated with lower adherence.The remaining factors showed either mostly no influence or were heterogeneous regarding the effect direction and statistical significance.ConclusionsThere are some factors that seem to have influence on adherence in patients taking OACA. However, due to the heterogeneity no general conclusions can be made also for these factors that can be applied to all indications, medications, settings, countries etc. The results should rather be considered as indications for factors that can have an influence on adherence to OACA.     

Influence of transition metal ions on NMR proton T1 relaxation times of serum, blood, and red cells

The spin-lattice relaxation rates (1/T1) of serum, whole blood, and red cells were measured vs several concentrations of transition metal ions. For comparative purposes, the similar experiments were repeated in water. The rates show a linear dependence on concentration of each ion for water, but nearly a linear dependence for blood and its constituents. The influence of each ion on 1/T1 in a sample was expressed by the slope (relaxivity) of the least-squares fitting of 1/T1 vs ion concentration. The relaxivities of Mn(II) in serum and of Fe(III) in serum and blood are greater than those in water, whereas the relaxivities of these ions in the other cases and of all the other ions in call cases are smaller than those in water. However, the relaxivity data show that Cr(III) in serum and blood affects the 1/T1 rates. The ratio of relaxivity of each sample to that of water is known as proton relaxation enhancement (PRR) factor (epsilon). The epsilon factors for present data suggest that the added ions are bound to proteins, and only Mn(II) in serum and Fe(III) in blood and serum are accessible to water.     

Methodology optimization and diversification for the investigation of virulence potential in Haemophilus influenzae clinical strains

Ten Haemophilus influenzae strains were isolated from patients aged between 1.6 - 24 years, with various diagnoses (acute meningitis, acute upper respiratory infection, otitis media and acute sinusitis). Identification was based on phenotypic and molecular characteristics; antibiotic susceptibility testing was performed by diffusion method according to CLSI standards 2011 for seven antibiotics. The results of molecular testing showed that all the studied strains produced an amplicon of 1000 bp with ompP2 primers indicating that all strains were H. influenzae. For six strains, the PCR amplicon obtained with bexA specific primers, proving that the strains were capsulated. The results of phenotypic testing showed that four strains were ampicillin nonsusceptible and (beta-lactamase-positive. The virulence potential of H. influenzae clinical strains was investigated by phenotypic methods, including the assessment of the soluble virulence factors on specific media containing the biochemical substratum for the investigated enzymatic factor, as well as the adherence and invasion capacity to HeLa cells monolayer using Cravioto modified method. The studied strains exhibited mainly a diffuse adherence pattern and different adherence indexes. Interestingly, two strains isolated from the same pacient (blood and CSF) showed a different degree of invasiveness, the strain isolated from blood being 20 times more invasive than the one isolated from CSF.     

Virus induced adherence of monocytes to endothelial cells

Abstract In this study we have demonstrated that infection of human umbilical vein endothelial cells (HUVEC) with Herpes simplex virus type 1 (HSV-1) resulted in an increased adherence of monocytes (MC). This enhanced adherence occurred at 3 h post infection (p.i.) when about 20% of the monolayer is infected and when there is no cytopathic effect observable in the monolayer. The adherence of human MC to virus-infected HUVEC monolayers proved to be effective and reproductible if a multiplicity of infection (MOI) of ten and a ratio of number of MC to number of HUVEC of 5 was used. The increased adherence was also induced by incubating non-infected HUVEC with the 'supernatant medium' of the HSV-1 infected cells, showing that soluble factors induced by viral infection are responsible for the increased adherence. The augmentation of MC adherence to infected endothelium was sensitive to tunicamycin treatment, suggesting that the MC adherence is probably mediated by glycoproteins expressed on the HUVEC membranes by virus infection.     

Virus induced adherence of monocytes to endothelial cells

In this study we have demonstrated that infection of human umbilical vein endothelial cells (HUVEC) with Herpes simplex virus type 1 (HSV-1) resulted in an increased adherence of monocytes (MC). This enhanced adherence occurred at 3 h post infection (p.i.) when about 20% of the monolayer is infected and when there is no cytopathic effect observable in the monolayer. The adherence of human MC to virus-infected HUVEC monolayers proved to be effective and reproducible if a multiplicity of infection (MOI) of ten and a ratio of number of MC to number of HUVEC of 5 was used. The increased adherence was also induced by incubating non-infected HUVEC with the 'supernatant medium' of the HSV-1 infected cells, showing that soluble factors induced by viral infection are responsible for the increased adherence. The augmentation of MC adherence to infected endothelium was sensitive to tunicamycin treatment, suggesting that the MC adherence is probably mediated by glycoproteins expressed on the HUVEC membranes by virus infection.