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Biomedical subjects

J G van Dam

Publications and source records attributed to J G van Dam.

7 recordsLinked to original sources
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

Acute primary infection with cytomegalovirus (CMV) in kidney transplant recipients results in the appearance of a phenotypically aberrant CD8+ T cell population.

Human cytomegalovirus (CMV) is a beta-herpesvirus that causes a chronic subclinical infection in healthy man. The immune system is unable to eliminate the virus completely, allowing virus to persist in a latent state. In the immunocompromised host, this equilibrium is disturbed, resulting in a clinical infection. In immunocompromised rats, clinical CMV infection is associated with an increase in NK cells and CD8+ T cells, including a phenotypically aberrant CD8+ T cell population. Using flow cytometry, we examined the effect of acute CMV infection on the composition of leukocyte subsets in immunocompromised patients. Therefore, we used peripheral blood of CMV seronegative patients receiving a kidney from a seronegative (control group) or a seropositive donor. Of the patients receiving a seropositive kidney, only the patients undergoing acute CMV infection were included (experimental group). Special attention was paid to the phenotype of the cytotoxic T cells. The development of acute CMV infection resulted in an increased NK cell number and an activation of both CD4+ and CD8+ T cells, as determined by HLA-DR expression. An aberrant CD8+ T cell subset with decreased expression of CD8 and TCR alphabeta appeared in the infected patients. Furthermore, the size of this subpopulation of CD8+ T cells is positively correlated with the viral load.

Acute Disease↗
PubMed1999

Pharmacokinetics and metabolism of rectally administered paracetamol in preterm neonates.

AIM: To investigate the pharmacokinetics, metabolism, and dose-response relation of a single rectal dose of paracetamol in preterm infants in two different age groups. METHODS: Preterm infants stratified by gestational age groups 28-32 weeks (group 1) and 32-36 weeks (group 2) undergoing painful procedures were included in this study. Pain was assessed using a modified facies pain score. RESULTS: Twenty one infants in group 1 and seven in group 2 were given a single rectal dose of 20 mg/kg body weight. Therapeutic concentrations were reached in 16/21 and 1/7 infants in groups 1 and 2, respectively. Peak serum concentrations were significantly higher in group 1. Median time to reach peak concentrations was similar in the two groups. As serum concentration was still in the therapeutic range for some infants in group 1, elimination half life (T1/2) could not be determined in all infants: T1/2 was 11.0 +/- 5.7 in 11 infants in group 1 and 4.8 +/- 1.2 hours in group 2. Urinary excretion was mainly as paracetamol sulphate. The glucuronide:sulphate ratio was 0.12 +/- 0.09 (group 1) and 0.28 +/- 0.35 (group 2). The pain score did not correlate with therapeutic concentrations. CONCLUSIONS: A 20 mg/kg single dose of paracetamol can be safely given to preterm infants in whom sulphation is the major pathway of excretion. Multiple doses in 28-32 week old neonates would require an interval of more than 8 hours to prevent progressively increasing serum concentrations.

Acetaminophen↗
PubMed1997

Infection with rat cytomegalovirus (CMV) in the immunocompromised host is associated with the appearance of a T cell population with reduced CD8 and T cell receptor (TCR) expression.

Infection with human cytomegalovirus (HCMV) mostly results in a chronic subclinical infection; the immune system is unable to eliminate the virus and is apparently in equilibrium with the persistent virus. In the immunosuppressed host this equilibrium is disturbed, resulting in clinical infection. Rat cytomegalovirus (RCMV) infection in its host can be used as a model for HCMV infection. Using flow cytometry we examined the effect of acute RCMV infection on the composition of leucocyte subsets in the peripheral blood of both immunocompetent and immunosuppressed (5 Gy total body irradiation) Lewis rats. Special attention was paid to the natural killer (NK) cells and the CD8+ T cells known to be involved in the control of viral infections. Furthermore, we determined the presence of leucocyte subsets in the internal organs by immunohistochemistry. In immunocompetent rats, infection caused a small increase in NK cells and a large increase in CD8+ T cells. In contrast, infection of immunosuppressed rats caused a marked increase in NK cells and a small increase in CD8+ T cells, consisting of T cells with reduced expression of both CD8 and TCR. This phenomenon is characteristic of anergic CD8+ T cells, possibly explaining the ability of the virus to escape elimination by the immune system. The increase of NK cells in the peripheral blood of immunosuppressed, RCMV-infected rats could also be detected in kidney, liver, lung and pancreas, but not in salivary gland. This could explain the long persistence of infectious virus in the salivary gland.

Animals↗
PubMed1992

[Ibuprofen meningitis].

A case of aseptic meningitis in an otherwise healthy women aged 47 yr after taking one tablet containing 400 mg ibuprofen is reported. The patient recovered in a few days.

Female↗