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Biomedical subjects

H J Bos

Publications and source records attributed to H J Bos.

At least 37 records · Page 2Linked to original sources
PubMed1990

Chemotaxis of the peritoneal cells and the detection of a chemo-attractant in the effluent from peritoneal dialysis patients.

The migration of peritoneal cells from 25 continuous ambulatory peritoneal dialysis patients and eight healthy women undergoing laparoscopy were studied. Peritoneal cells of continuous ambulatory peritoneal dialysis patients migrated to commonly used chemoattractants, like N-formyl-methionyl-leucyl-phenyl-alanine-methyl- ester and casein, but they also migrated to high concentrations of recombinant interleukin-1 alpha and to endotoxin (lipopolysaccharide). In the peritoneal effluent from continuous ambulatory peritoneal dialysis patients a rather heat stable chemoattractant was found with a molecular weight of 40-200 kDa with an optimal activity at approximately 125 kDa. The chemoattractant is a protein and is not complement factor 5a or interleukin-1 and was only found in peritoneal effluent from continuous ambulatory peritoneal dialysis patients, but not in peritoneal fluid from healthy women undergoing laparoscopy. Therefore, peritoneal dialysis might induce the generation of a chemoattractant. The optimal chemotactic response of peritoneal cells from continuous ambulatory peritoneal dialysis patients to N-formyl-methionyl-leucyl-phenyl-alanine-methyl- ester in medium could be enhanced by replacing the medium by peritoneal effluent. So the chemotaxis of peritoneal cells to the factor in the peritoneal effluent is caused by another mechanism, which might involve different cell surface receptor populations, than the chemotactic response to N-formyl-methionyl-leucyl-phenyl-alanine-methyl-ester.

Adult↗
PubMed1989

Isolation and partial characterisation of a potentially pathogenic cysteine proteinase from adult Dictyocaulus viviparus.

Dictyocaulus viviparus adult worms feed on pulmonary tissues and cause significant pathology in the bovine host. In this report, acidic extracts of these organisms were examined for cysteine proteinase activity. A soluble thiol-dependent proteinase with native molecular weight of approximately 25 kDa was isolated and partially purified. This enzyme had maximal activity at acidic pH and showed inhibitor susceptibilities similar to the vertebrate acidic cysteine proteinases. When stored at 4 degrees C, it was stable at pH 5.0 for at least 10 days and at pH 7.0 for at least 24 h. The D. viviparus cysteine proteinase was capable of degrading type I collagen and hemoglobin. It is suggested that this enzyme may be involved in the nutrition of this parasite and/or have the potential to contribute to bronchial pathology in cattle.

Animals↗
PubMed1989

Peritoneal dialysis fluid induces change of mononuclear phagocyte proportions.

Peritoneal macrophages from uninfected continuous ambulatory peritoneal dialysis (CAPD) patients in general show two different, endogenous peroxidase activity (PA) patterns: exudate and negative. This suggests, in accordance with the animal model, that these macrophages are changed proportionately in CAPD patients. This chronic change may be caused by mechanical stimulation alone (massage) or the composition of the dialysis fluid used. Therefore in the rat model both physiological saline and commercial dialysis fluid were intraperitoneally (i.p.) administrated. Our results on the PA-pattern of peritoneal macrophages do indicate that a single i.p. administration of commercial dialysis fluid induced an acute exudate, especially when compared with the minor saline effect. These results are confirmed by the percentage of macrophages positive for a differentiation antigen recognized by the monoclonal antibody ED2. In addition the percentage of Fc-receptor positive peritoneal cells is more enhanced after i.p. injection of dialysis fluid when compared with the saline effect. These findings strongly suggest that the dialysis fluid used in peritoneal dialysis patients is the inducer of exudate peritoneal macrophages in these patients.

Animals↗
PubMed1989

Most CD4+ T cells from human immunodeficiency virus-1 infected patients can undergo prolonged clonal expansion.

We have addressed the capacity of HIV-1 infection to alter the growth of primary CD4+ T cells, but at the clonal level. Single T cells were expanded in the presence of PHA, IL-2, and small numbers of accessory dendritic cells. We report two new findings. First, T cells from seropositive individuals, even those with AIDS and markedly reduced CD4+ counts, exhibit a normal cloning efficiency, and proliferative capacity. This result is in contrast to two prior reports of a low cloning efficiency in CD4+ T cells from HIV-1-infected patients. Second, when we added high doses of exogenous HIV-1 to T cell clones from control subjects, we observed infection but not cytotoxicity or loss of CD4+ cells, following addition of virus stocks at days 0, 3, and/or 7 of clonal growth. The same HIV-1 isolates markedly reduced CD4+ T cells in bulk mononuclear cultures. When tested at day 11, HIV-1 mRNA was expressed in some cells of exogenously infected clones by in situ hybridization; when tested at day 18, several clones could transactivate a TAT-sensitive cell line. These findings suggest that the loss of CD4+ T cells in infected individuals is not the inevitable result of the activation of latent infection, or spread of a productive infection, during clonal growth.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Cytotoxic effects of commercial continuous ambulatory peritoneal dialysis (CAPD) fluids and of bacterial exoproducts on human mesothelial cells in vitro.

Cultured human mesothelial cells were exposed to peritoneal dialysis fluids, supernatants from cultures of Staphylococcus aureus and S. epidermidis, and antibiotics. Mesothelial cell monolayer cultures were derived from surgically removed omentum. The cytotoxicity of various agents for the cultured mesothelial cells was measured by a 51 Cr-release assay. All brands of fresh peritoneal dialysis fluids induced a more than 50% 51 Cr-release after 18 h. Morphological changes observed included retraction and shrinking of cells, pyknosis of the nuclei and, finally, detachment of cells over an 18-h period. Neutralization of the acid (pH 5.2-5.5) fluids to pH 7.3 did not abolish the cytotoxicity. In contrast, effluent dialysis fluids were not toxic for mesothelial cells; neither was acid (pH 5.5) culture medium nor culture medium with glucose up to 2%. However, higher glucose concentrations induced increasing 51 Cr-release. Furthermore, filter-sterilized supernatants of S. aureus were cytotoxic for mesothelial cell monolayers in 4/7 (57%) strains of S. aureus tested. In contrast, only 4/29 (14%) strains of S. epidermidis produced cytotoxic exoproducts (p = 0.03). Antibiotics were not found to be cytotoxic, with the possible exception of erythromycin. We conclude that currently available peritoneal dialysis fluids are cytotoxic for mesothelial cells in vitro and that during episodes of peritonitis exoproducts of some bacterial strains may further reduce mesothelial cell viability.

Cell Survival↗
PubMed1989

The effect of dwell time on peritoneal phagocytic defense of chronic peritoneal dialysis patients.

We studied the phagocytic capacity of peritoneal macrophages (PM) isolated from effluents after 4 different dwell times (1.5 to 15 hours) in six stable CAPD patients. In addition IgG and C3 levels as well as opsonic activity of the effluents were measured. Both IgG levels and opsonic activity increased significantly with prolonged dwell times. The same held true for the number of phagocytes and their phagocytic capacity. Thus prolonged dwell time enhanced both opsonic activity and phagocytic capacity significantly. As in CCPD the dwell time period between (dis)connection procedures is much longer than in CAPD, this might play an important role in the lower peritonitis rate among CCPD-treated patients.

Cell Count↗
PubMed1988

Distinct subpopulations of elicited human macrophages in peritoneal dialysis patients and women undergoing laparoscopy: a study on peroxidatic activity.

The endogenous peroxidatic activity (PA) pattern of peritoneal macrophages from 24 continuous ambulatory peritoneal dialysis (CAPD) patients and from five healthy women undergoing laparoscopy was studied. In general, the macrophages showed two different PA patterns in vivo: exudate and negative macrophages. However, two of 24 CAPD patients showed resident macrophages, the first described in vivo in man. Since, in general, the examined human peritoneal macrophages are exudate and PA-negative, this suggests, in accordance with the animal model system, that a chronic sterile inflammation exists in the peritoneal cavity of CAPD patients and healthy women undergoing laparoscopy. After 2 hr culture, blood monocytes and peritoneal macrophages transformed into cells with the characteristics of exudate-resident and resident macrophages, so isolation procedures that include short periods of culture can change the developmental stage of human monocytes and macrophages.

Female↗
PubMed1986

Use of ELISA to assess lungworm infection in calves.

The enzyme-linked immunosorbent assay (ELISA) technique was applied to the detection of lungworm infections in calves. In experimentally infected animals different responses to larval and adult worm antigens were observed. The response to adult worm antigens was delayed in vaccinated animals when infection occurred by the gradual uptake of infective larvae from contaminated pasture. A serological survey in The Netherlands demonstrated a high incidence of lungworm infection in both vaccinated and unvaccinated herds. There was a good correlation between anti-adult worm and anti-larval ELISA-titres. ELISA appeared to be a useful technique for assessing the level of lungworm infection in a herd.

Animals↗
PubMed1985

Serodiagnosis of lungworm infection in calves using ELISA.

Soluble antigens were prepared from adult Dictyocaulus viviparus worms and from parasitic larval stages. Circulating antibody titres against these antigens were determined during experimental and field challenge studies. Stage-specific responses were found in vaccinated and non-vaccinated calves after challenge infection. Titre-values are probably correlated with the number of larvae reaching the lungs and the number of larvae developing into later larval resp. adult stages. The ELISA-technique appeared to be useful for diagnosis of lungworm infection level in cattle herds and has been applied in a sero-epidemiological survey in the Netherlands.

Animals↗
PubMed1981

A case of Acanthamoeba keratitis in The Netherlands.

A severe kerato-iritis of the right eye of a 36-year-old healthy man constituted a diagnostic and therapeutic problem. More than seven months after the onset of his complaints a cornea transplantation was carried out because a large abscess had developed in the stroma of the cornea and perforation was feared. Amoebae, belonging to the free-living genus Acanthamoeba, were found in the excised corneal disc. Similar infections have been described earlier in the USA, in England and in Germany. The case described here is the first well documented one in the Netherlands. The case history and identification of the amoeba are described. Data from the literature on epidemiology, pathogenicity and treatment are discussed.

Adult↗
PubMed1980

A seroepidemiological study of amebiasis in Surinam by the enzyme-linked immunosorbent assay (ELISA).

Sera from nine populations in Surinam, South America, were screened for antibodies against Entamoeba histolytica by the enzyme-linked immunosorbent assay (ELISA) technique and a precipitin test (gel diffusion or counterimmunoelectrophoresis). In two small surveys in 1974 and 1978, a high rate of clinically significant ELISA titers was found in a rather isolated group of Amerindians living near the Brazilian border, predominately in the youngest age groups. Amerindians living near the coast showed a low level of seropositivity. Low levels were also found in Bush Negro villages in the interior of Surinam and in Hindustani school children from the savannah area. A high frequency of ELISA titers greater than or equal to 320, indicating a high rate of invasive amebiasis, was detected in persons in a mental institution in Paramaribo. It is concluded that the ELISA, which is much more sensitive than the precipitin tests, is a useful screening test for assessing the prevalence of invasive amebiasis on an epidemiological scale.

Amebiasis↗
PubMed1980

Serum-inhibited toxicity of Entamoeba histolytica.

The cytopathogenic effect (CPD) of soluble antigens prepared from various strains of Entamoeba histolytica, differing in virulence, was assayed on monolayers of baby hamster kidney cells growing in microtiter plates. Serum-inhibited toxicity could be detected in all these strains and in E. invadens, but not in the Huff strain and in an Acanthamoeba species. Gel chromatography demonstrated a peak activity of the toxin in a fraction with M.W. between 35,000 and 45,000. Other experiments learned that the toxin is a heat-labile glycoprotein, stable between pH 4 and 10, degradable by trypsin, dependent in its activity on sulphydryl goups, and inhibited by anti-E. histolytica IgG and nonimmune serum factors with a M.W. between 50,000 and 100,000. It is also excreted by the ameba and this may explain the effect of serum on contact lysis, induced by intact amebae on BHK cells.

Cytotoxicity, Immunologic↗