Biomedical subjects

C A Bruggeman

Publications and source records attributed to C A Bruggeman.

At least 19 recordsLinked to original sources

PubMed2003

[Transmural care for HIV-seropositive drug users: experiences from Southeast Limburg, the Netherlands].

In 1999 the decision was taken to start a transmural consultation service for HIV-seropositive drug users at the Consultation Office for Alcohol and Drugs [Dutch acronym: CAD] in Heerlen, the Netherlands. This consultation service was run by an AIDS consultant from Maastricht University Hospital together with the addiction physician from the CAD. In the period 1 November 1998-30 April 2002 29 HIV-seropositive drug users made use of this consultation service. Highly active antiretroviral therapy was prescribed to 23 patients during an average of 21 months (range: 4-51). Eighteen patients responded well to this therapy (viral load < 50 copies/ml) after 12-24 weeks of treatment and thereafter during 21 months. Direct observed therapy (DOT) was applied to 16 patients. Therapeutic failure due to poor compliance was observed in 3 patients. Two of them had initially been successfully treated with medication whilst under supervision but the treatment failed when they became responsible for taking their own medication. It seems that involving the Consultation Office for Alcohol and Drugs in the treatment and DOT has a favourable effect on the treatment of HIV-positive drug users.

Antiretroviral Therapy, Highly Active↗

PubMed2003

Chlamydia pneumoniae infection induces an unstable atherosclerotic plaque phenotype in LDL-receptor, ApoE double knockout mice.

OBJECTIVES: To study whether Chlamydia pneumoniae (Cpn) infection affects atherosclerotic plaque morphology in atherogenic (LDLr/ApoE(-/-)) mice. METHODS: In mice sacrificed 20 or 40 weeks after Cpn infection aortic arch sections were analysed for lesion and fibrous cap area and the presence of matrix metalloproteinases (MMP)-2 and -9. RESULTS: All infected mice seroconverted, demonstrated Cpn DNA in their aortas on PCR and developed atherosclerotic plaques. Infection was not associated with changes in lesion area or type, but was associated with reduced the fibrous cap area and increased MMP-2 and -9 immunoreactivity. CONCLUSION: These findings suggest that Cpn infection may predispose to plaque instability.

Actins↗

PubMed2003

Performance of five serological chlamydia antibody tests in subfertile women.

BACKGROUND: Micro-immunofluorescence (MIF) is widely used for chlamydia antibody testing (CAT). Recently a species-specific MIF and three enzyme-linked immunosorbent assay (ELISA) tests have been introduced. We compared five commercially available CAT tests, using laparoscopy as a reference, and evaluated whether combinations of tests could improve the predictive value of CAT. METHODS: In a consecutive cohort of 315 subfertile women, results of the five CAT tests were correlated to findings at laparoscopy. Likelihood and odds ratios (OR) were calculated for single tests and for combinations of tests. RESULTS: Of the tests evaluated, MIF Labsystems had the best diagnostic performance (OR 15.7), while pELISA Medac (OR 8.2) was the best of the three ELISA tests. Stepwise logistic regression analysis showed that performance of MIF Labsystems could not be improved by adding a second test. Significant cross-reactivity with C. pneumoniae antibodies was found in all tests evaluated, except in pELISA Medac. CONCLUSIONS: In screening for tubal factor subfertility, MIF Labsystems was superior to the ELISA tests evaluated, and combining two CAT tests did not improve its predictive value. Economic analysis will show whether serial testing by pELISA Medac, and retesting positive samples by MIF Labsystems, is most cost-effective. In CAT, cross-reactivity with C. pneumoniae antibodies is still a major concern.

Antibodies, Bacterial↗

PubMed2003

Dissemination of rat cytomegalovirus through infected granulocytes and monocytes in vitro and in vivo.

The role of leukocytes in the in vivo dissemination of cytomegalovirus was studied in this experiment. Rat cytomegalovirus (RCMV) could be transferred to rat granulocytes and monocytes by cocultivation with RCMV-infected fibroblasts in vitro. Intravenous injection of purified infected granulocytes or monocytes resulted in a systemic infection in rats, indicating that our model is a powerful tool to gain further insight into CMV dissemination and the development of new antivirals.

Animals↗

PubMed2003

Virally encoded G protein-coupled receptors: targets for potentially innovative anti-viral drug development.

Various herpes- and poxviruses contain DNA sequences encoding proteins with homology to cellular chemokine receptors, which belong to the family of G protein-coupled receptors (GPCRs). Since GPCRs play a crucial role in cellular communication and chemokine receptors play a prominent role in the immune system, the virally encoded GPCRs may be crucial determinants of viral action. The Kaposi's sarcoma-associated herpesvirus (KSHV, or human herpesvirus 8), implicated in the pathogenesis of Kaposi's sarcoma (KS), a highly vascularized tumor, encodes a GPCR, referred to as ORF74. This virally encoded receptor was found to induce tumorigenesis and transgenic expression of ORF74 induces an angioproliferative disease resembling KS. Cytomegalovirus (CMV), suggested to play a role in atherosclerosis, encodes four GPCRs, among which US28. This virally encoded GPCR is able to induce migration of smooth muscle cells, a feature essential for the development of atherosclerosis. Remarkably, the KSHV and some CMV-encoded GPCRs display constitutive activity, while their cellular homologs do not. It remains to be determined whether this phenomenon contributes to the pathogenesis of viral action. Also, the family of poxviruses encodes GPCRs of which the function is not clear yet. In this review we will give an overview of the different virally encoded GPCRs, and discuss their putative role in viral action and potential as drug target.

Antiviral Agents↗

PubMed2002

A rat cytomegalovirus strain with a disruption of the r144 MHC class I-like gene is attenuated in the acute phase of infection in neonatal rats.

We previously generated an RCMV strain in which the r144 gene, encoding a major histocompatibility complex class I homolog, had been deleted (RCMVdelta r144). To investigate the role of r144 during acute infection of neonatal rats, we infected three days-old neonatal rats with either RCMVdelta r144 or wild type (wt) RCMV and the presence of infectious virus as well as viral DNA in various organs was determined at either 3, 5 or 21 days p.i.. In addition, we assessed both type and number of inflammatory cells in these organs. Interestingly, a significantly lower concentration of infectious virus as well as viral DNA was found in spleens of RCMVdelta r144-infected rats than in those of wt RCMV-infected animals at 3 days p.i.. At the same time point, a significantly lower amount of infiltrating NK cells and monocytes/macrophages was seen in the spleens of RCMVdelta r144-infected rats than in spleens of rats infected with wt RCMV. At 21 days p.i., RCMVdelta r144-infected rats were found to have lower virus titers in the salivary glands than wt RCMV-infected animals. Significant differences between RCMVdelta r144- and wt RCMV-infected rats were detected neither at other time points nor at other sites. We conclude that after infection of neonatal rats, the replication of RCMVdelta r144 is severely restricted compared to wt RCMV.

Acute Disease↗

PubMed2002

Chlamydophila pneumoniae (Chlamydia pneumoniae) accelerates the formation of complex atherosclerotic lesions in Apo E3-Leiden mice.

OBJECTIVE: Atherosclerosis is an inflammatory process and is characterised by the presence of T-lymphocytes in the lesions. To study the role of Chlamydophila pneumoniae (C. pneumoniae) in this process and the effect of infection on T-cell influx, we infected Apo E3-Leiden mice with C. pneumoniae and investigated the effect on lesion development and T-cell influx in atherosclerotic lesions at different time points post infection (pi). METHODS: Nine week old mice, fed an atherogenic diet, were either mock-infected or infected with C. pneumoniae and sacrificed at 1, 6 and 9 months pi. Longitudinal sections of the aortic arches of the mice were stained with hematoxylin-eosin for atherosclerotic lesion type and lesion area analysis, or with rabbit-anti-CD3(+) to detect the presence of T-cells in the atherosclerotic lesions. T-cell influx was expressed as number of T-lymphocytes/lesion area. RESULTS: At 1 month pi, type 1, 2 and 3 lesions were present. At other time points pi, more complex lesion types 4, 5a and 5b were also present. Although infection did not influence the total lesion number or area, we observed an effect of C. pneumoniae infection on lesion type. Infection resulted in a significant shift in lesion formation from type 3 to type 4 (P=0.022) at 6 months pi, and from type 4 to type 5a (P=0.002) at 9 months pi. T-cells were observed at every time point pi. At 1 month pi, a significant increase in T-cell influx in the C. pneumoniae-infected atherosclerotic lesions was observed (P=0.0005). CONCLUSION: This study shows that C. pneumoniae infection enhances the inflammatory process by increasing T-lymphocytes in the plaque and accelerates the formation of complex lesions.

Animals↗

PubMed2001

Prevention of cytomegalovirus infection-enhanced experimental obliterative bronchiolitis by antiviral prophylaxis or immunosuppression in rat tracheal allografts.

In this study, the prevention of rat cytomegalovirus (RCMV) infection-enhanced experimental obliterative bronchiolitis in rat tracheal allografts was investigated. RCMV infection markedly enhanced cell proliferation and histological changes of obliterative bronchiolitis, a form of chronic rejection after lung transplantation. These alterations were linked to increased interleukin (IL)-2 and tumor necrosis factor-alpha (TNF-alpha) immunoreactivity, and reduction of IL-10 expression. In recipient rats with acute RCMV infection, prophylaxis with either ganciclovir (DHPG) or hyperimmune serum (HIS) totally prevented RCMV infection-enhanced tracheal occlusion. DHPG treatment initiated during acute RCMV infection also reduced lesion development but markedly less than DHPG prophylaxis. Treatment of acute RCMV infection with HIS alone or in combination with DHPG had no significant effect on tracheal occlusion. Inhibition of the transcription of cytokines by high doses of cyclosporine A significantly reduced RCMV infection-enhanced tracheal obliteration. In rats with chronic RCMV infection, obliterative alterations were prevented by DHPG prophylaxis initiated at the time of transplantation. Prophylaxis either with DHPG or HIS did not affect the amount of infectious RCMV recovered from host salivary glands, nor were there differences seen in RCMV major immediate early DNA expression in tracheal allografts between different antiviral drug regimens. Immunohistochemical analysis of allografts revealed that inhibition of tracheal occlusion by antiviral prophylaxis was associated with a reduction in the number of ED1(+) macrophages and cells staining for Th1 cytokines and TNF-alpha, while immune modulation by cyclosporine A up-regulated IL-10 production. In conclusion, the results of the present study suggest that the CMV infection-enhanced chronic rejection develops independently of viral load but requires both immune activation and simultaneous CMV gene expression beyond immediate early genes.

Acute Disease↗

PubMed2001

Cytomegalovirus infection, viral DNA, and immediate early-1 gene expression in rejecting rat liver allografts.

BACKGROUND: Cytomegalovirus (CMV) infection has been linked to acute and chronic rejection. We have previously shown that concomitant rat cytomegalovirus (RCMV) infection increases portal inflammation and bile duct destruction in rejecting rat liver allografts. Many of the pro-inflammatory effects of CMV have been attributed to the immediate early (IE) proteins of CMV. We wanted to investigate whether RCMV and IE-1 gene expression persist in the liver graft in our model. METHODS: Liver transplantations were performed from PVG (RT1c) into BN (RT1n) rats. One day after transplantation, the rats were infected with RCMV. No immunosuppression was given. The graft infection was studied by viral culture, immunofluorescence, DNA in situ hybridization and RT-PCR for the detection of IE-1 mRNA at various time points. RESULTS: RCMV caused an active infection from 5 days to 2 weeks after transplantation, during which infectious virus was found in the graft. Thereafter the cultures were negative. RCMV antigens and DNA were found in hepatocytes, endothelial, inflammatory, and bile duct cells during the active infection. At 4 weeks, RCMV DNA positive hepatocytes, endothelial, inflamma tory, and bile duct cells could still be found, but in much smaller quantities. IE-1 mRNA expression was, however, only detected during the active infection, not at 4 weeks postinfection. CONCLUSIONS: RCMV IE-1 expression does not persist in the graft after the active infection, although some viral DNA can be detected in the graft up to 4 weeks. In our model, the CMV-induced increase in graft damage does not seem to require the continued expression of IE-1.

Animals↗

PubMed2001

Immune evasion by human cytomegalovirus: lessons in immunology and cell biology.

The human cytomegalovirus (HCMV) has dedicated a significant part of its genome to genes encoding molecules that modulate the host immune response. Many of these genes have homologues in the host genome. Others, however, are unique in the sense that no obvious primary sequence identity is found in the available databases. The HCMV gene products interfere with the activation of MHC class I and class II restricted T cells and NK cells, modify the function of cytokines and their receptors, interact with complement factors and modulate signal transduction and transcription factor activity, in addition to interference with many other cellular functions. Investigation of these evasion strategies has not only improved our understanding of HCMV pathogenesis, but has also provided unexpected, novel insights into basic cell biological and immunological processes.

Amino Acid Sequence↗

PubMed2001

Rat cytomegalovirus open reading frame R44 is an early-late gene that encodes a nuclear protein.

Rat cytomegalovirus (RCMV) open reading frame R44 is the homolog of human cytomegalovirus gene UL44, which encodes the DNA polymerase accessory protein. Here, we show that R44 is transcribed as a 3.6-kb mRNA within the early and late phases of infection in vitro. In order to find potential monoclonal antibodies (MoAbs) directed against the R44-encoded protein (pR44), a panel of anti-RCMV MoAbs was screened for binding to pR44 recombinant proteins. Thus, an anti-pR44 MoAb, termed RCMV8, was identified. By using this MoAb, pR44 could be detected as early as 8 h after RCMV infection in vitro. The pR44 protein was determined to have a molecular mass of approximately 55 kDa and was found to be localized to the nucleus of RCMV-infected cells.

Animals↗

PubMed2001

The role of cytomegalovirus-encoded homologs of G protein-coupled receptors and chemokines in manipulation of and evasion from the immune system.

Cytomegaloviruses (CMVs) have the ability to persist lifelong within the infected host. This ability implies that these viruses are highly adapted to their hosts. Most importantly, they will have to employ strategies to remain hidden from the host's immune system. Virus genes predicted to be involved in these strategies include genes encoding homologs of cellular immune effector or regulatory proteins, such as chemokine (CK) receptor-like G protein-coupled receptors (GPCRs), CKs and MHC class I molecules. These genes may have been pirated by the virus during the long co-evolution of pathogen and host. In light of the crucial roles that GPCRs, CKs and MHC class I molecules play in the normal physiology of the host, it is to be expected that the CMV homologs of these proteins may have a profound impact on this physiology and, at the same time, serve vital functions in maintenance as well as replication of the virus within the infected host. As a consequence, these viral homologs can be envisaged as attractive targets for novel anti-viral strategies. The aim of this report is to present an overview of the current state of knowledge on the (putative) functions of the CMV homologs of GPCRs and CKs.

Amino Acid Sequence↗

PubMed2001

Different profiles of cytomegalovirus RNA transcripts and anti-cytomegalovirus IgM antibodies in renal transplant recipients.

BACKGROUND: A difference in anti-cytomegalovirus IgM antibody profile has been found between sera from acutely cytomegalovirus (CMV)-infected patients and sera from CMV-infected patients with subclinical infection. OBJECTIVES: The aim of this study is to investigate whether such different IgM antibody responses are correlated with differences in the expression of CMV immediate early and late mRNAs. STUDY DESIGN: We have investigated the anti-CMV IgM response in 46 renal transplant recipients by employing two commercially available IgM kits (AxSYM and IMX) as well as two novel enzyme-linked immunosorbent assays (ELISAs), which were developed using recombinant ppUL32 (pp150) and pUL80a (p38), respectively. The results were compared with four direct CMV diagnostic tests: pp65 antigenemia, viral culture and nucleic acid sequence-based amplification (NASBA), detecting either CMV immediate early 1 (IE1) mRNA (IE1-NASBA), or CMV pp67 (late) mRNA (pp67-NASBA). RESULTS: Analysis of all CMV-infected recipients (n=28) showed that in 16 recipients (group I) more than one direct test became positive after transplantation, while in the other 12 recipients (group II), IE1-NASBA was the only direct test to become positive. In group I, 100, 81, 100 and 50% of the recipients were IgM-positive with AxSYM, IMX, p38 and pp150, respectively. In group II, 100, 83, 17 and 83% of the recipients were IgM-positive with AxSYM, IMX, p38 and pp150, respectively. CONCLUSIONS: Our data indicate that the IgM-response against p38 and pp150 differs significantly (P<0.01) between group I recipients with productive CMV infection, and group II recipients with a non-productive CMV infection which may be of diagnostic and prognostic relevance.

Antibodies, Viral↗

PubMed2001

Chlamydia pneumoniae and screening for tubal factor subfertility.

Chlamydia antibody testing (CAT) by micro-immunofluorescence (MIF) tests has been introduced into the fertility work-up as a screening test for tubal factor subfertility. In this study the role of C. pneumoniae antibodies, as a cause for false positive CAT results due to cross-reactivity with C. trachomatis antibodies in the MIF test, has been evaluated. In 240 subfertile women serological data were compared to laparoscopy findings. The prevalence of C. pneumoniae antibodies using enzyme-linked immunosorbent assay (ELISA) was 75% and did not differ between patients with and without tubal pathology. C. pneumoniae antibodies were found in 87% of women with a positive MIF test (> or =32), and in 66% with a negative MIF test (P < 0.0005). Using ELISA instead of MIF for the detection of C. trachomatis antibodies, C. pneumoniae antibodies were found in 87% of C. trachomatis positive women, and in 69% of C. trachomatis negative women (P < 0.0005). Patients without tubal factor subfertility but a positive MIF test showed C. pneumoniae antibodies more frequently than patients without tubal factor subfertility and a negative MIF test. Therefore it was suggested that C. pneumoniae antibodies may be the cause of false positive CAT results. Remarkably, tubal pathology was more common in patients who had antibodies to both C. trachomatis and C. pneumoniae.

Adult↗

PubMed2000

Rat cytomegalovirus R89 is a highly conserved gene which expresses a spliced transcript.

In all sequenced herpesvirus genomes, a homolog of the herpes simplex virus type 1 UL15 gene has been identified. This gene encodes a protein that is involved in viral genome maturation. Although transcription of the alphaherpesvirus UL15 gene has been analyzed in detail, not much is known about the expression of its betaherpesvirus homologs. We therefore set out to characterize transcription of the rat cytomegalovirus counterpart of UL15, R89. Here we report that R89 consists of two exons separated by a 4.7-kb intron. The spliced R89 transcript, which is expressed at late times postinfection (p.i.), has the capacity to encode a protein of 670 amino acids with a calculated molecular mass of 77.1 kDa. The predicted amino acid sequence of this protein is highly similar to that of the proteins predicted to be encoded by the human cytomegalovirus UL89 and murine cytomegalovirus M89 genes (64.3 and 84.5% overall identity, respectively). The region between R89 exon 1 and exon 2 was found to contain five additional genes, r90, R91, R92, R93 and R94, the latter two of which are conserved among all herpesviruses. We show that these genes are transcribed in a highly complex fashion, resulting in numerous mono- and polycistronic mRNAs.

Amino Acid Sequence↗

PubMed2000

Rat cytomegalovirus infection in kidney allograft recipients is associated with increased expression of intracellular adhesion molecule-1 vascular adhesion molecule-1, and their ligands leukocyte function antigen-1 and very late antigen-4 in the graft.

BACKGROUND: Cytomegalovirus (CMV) infection is suggested to be a risk factor for chronic rejection. We have recently shown that rat CMV (RCMV) increases the inflammatory response and accelerates chronic rejection in a model of rat kidney allograft. In this study, the early inflammatory response and time-related expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and their ligands, leukocyte function antigen-1 (LFA-1) and very late antigen-4 (VLA-4), in the grafts were investigated in RCMV-infected rats and compared to noninfected rats developing chronic rejection. METHODS: Transplantations were performed in a rat strain combination of DA (RT1a)->BN (RT1n) receiving triple drug immunosuppression. One group of rats was infected with RCMV, and the other was left uninfected. The grafts were harvested at different time points after transplantation. The adhesion molecules, their ligands and activation markers, MHC class II antigens and interleukin-2-receptors (IL-2-R), were demonstrated by monoclonal antibodies and immunoperoxidase staining from frozen sections of the grafts. Graft histology was evaluated according to the Banff criteria. RESULTS: RCMV caused a significant, prolonged increase of VCAM-1 and ICAM-1 expression in the vascular endothelium compared to the noninfected grafts. Also, the number of cells expressing activation markers, LFA-1 and VLA-4 was significantly enhanced in these animals. Significantly enhanced histological changes of chronic rejection were seen in the RCMV-infected group. CONCLUSIONS: Prolonged, increased expression of ICAM-1 and VCAM-1, and increased numbers of inflammatory cells expressing their ligands in the CMV infected grafts, were associated with accelerated chronic allograft nephropathy.

Animals↗

PubMed2000

Effects of cytomegalovirus infection and prolonged cold ischemia on chronic rejection of rat renal allografts.

Previous studies have demonstrated that both cytomegalovirus (CMV) infection and prolonged cold ischemia of the allograft (CI) are associated with chronic rejection of renal transplants. The purpose of this study is to investigate the effect of CMV infection, of CI and of the combination of both, on the progression of chronic rejection, and to obtain a more detailed insight in their effects on the expression of adhesion molecules. Therefore, a rat transplantation model was used. Lewis recipients of renal allografts (with and without CI) from MHC-incompatible Brown Norway rats were inoculated with rat CMV or left uninfected. CMV infection alone resulted in an increased influx of CD4+ cells and macrophages early after infection, and in an increase in glomerular sclerosis and intima proliferation. CI caused an increase in infiltrating NK cells and an effect on intimal proliferation, glomerular sclerosis, and tubular atrophy. When CMV infection and CI were combined, an additive effect could be measured. This was however not the case for the function of the kidney. The creatinin showed a synergistic effect of the two influencing factors. Due to the CMV infection, an increase in CD49d cells was detected. CI resulted in an increase in CD18 cells and an increase in the expression of CD62P on vessels, and CD54 and CD44 on tubules. When CMV infection and CI were combined, all the effects caused by CMV and CI alone were present in an additional way. The results of the present study suggest that special attention should be paid to the recipient of an ischemically injured graft when either the donor or the recipient is CMV-infected. The patterns seen in histology, the infiltration of leukocytes and the expression of adhesion molecules, suggest that CI and CMV infection both have an effect on rejection, but act by different mechanisms.

Animals↗

PubMed2000

Rat cytomegalovirus replication in the salivary glands is exclusively confined to striated duct cells.

The salivary gland is the preferred organ for cytomegalovirus (CMV) replication and viral persistence. In order to identify the nature of infected cells and to study viral replication in more detail, several experiments were conducted. Using the rat CMV (RCMV) model, acutely infected young adult rats (6 weeks of age) and new-born rats (3 days of age) were infected, and submandibular, parotid and sublingual glands were harvested at different time points after infection. For identification of the nature of infected cells, immunohistochemistry, in situ hybridisation and electron microscopic techniques were used. In young adult animals, the submandibular gland was the preferred organ for RCMV replication. The parotid and sublingual glands contained fewer viruses than the submandibular gland. In contrast, in new-born rats, the main site of RCMV replication was the sublingual gland, while the submandibular and parotid glands contained low amounts of virus. No virus could be detected in the parotid glands. In all glands of RCMV-infected animals, the infection was exclusively confined to striated duct cells. Infection resulted in a cellular inflammatory response which was mostly located in the interlobular duct region, whereas only few inflammatory cells were found in the neighbourhood of infected striated duct cells. This phenomenon may contribute to the long persistence of the virus in this organ.

Animals↗