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Biomedical subjects

H M Jansen

Publications and source records attributed to H M Jansen.

At least 91 records · Page 5Linked to original sources
PubMed1996

Cytokine production by T-cell clones from bronchoalveolar lavage fluid of patients with asthma and healthy subjects.

Cytokines produced by T-lymphocytes play an important regulatory role in inflammation in the airways of asthmatic patients. Our aim was to analyse the cytokine production by T-cell clones from bronchoalveolar lavage fluid (BAL) of patients with allergic asthma and the cytokine production of clones from the patients' peripheral blood (PB), as well as from BAL and blood from healthy controls. In 75 randomly selected CD4+ T-cell clones, we assessed the production of interleukin (IL)-2, IL-4 and interferon-gamma (IFN-gamma). After stimulation with anti-CD3, the clones from the asthmatic patients' BAL (A-BAL) produced significantly more IL-4 and IFN-gamma (median 0.32 and 4.17 ng.mL-1, respectively) than clones from A-PB (0.11 and 1.12 ng.mL-1, respectively). No evidence was found for a dominance of a type 1 or type 2 T-helper cell (Th1- or Th2)-cytokine profile in any of the groups. In three out of nine clones tested, the stimulation with anti-CD2/CD28/phorbol myristate acetate (PMA) induced a shift of the IFN-gamma/IL-4 ratio towards a Th2-type cytokine profile. Our results suggest that the clones from the asthmatic patients' bronchoalveolar lavage were derived from a more differentiated T-cell population. In several clones, the cytokine profile was still modulated by the stimulus applied. Similarly, local conditions in the airways may be involved in directing the cytokine production of T-cells.

Adult↗
PubMed1996

Pharmacokinetics and dosimetry of cobalt-55 and cobalt-57.

UNLABELLED: The isotopes 55Co and 57Co have been evaluated for PET and SPECT imaging in several clinical brain studies. For clinical application of cobalt, it is important to know the delivered radiation dose. The biodistribution of 55Co in both rat and humans after intravenous (bolus)-administration was studied. Based on pharmacokinetic data, radiation dose calculations according to the MIRD system are presented. By combining present measurements with literature data on 60CoCl2, the radiation dose delivered by 56CoCl2 (T1/2 78.8 days) and 57CoCl2 (T1/2 = 270 days) could be assessed. METHODS: Whole-body Co-PET was performed in two healthy volunteers and one rat after intravenous injection of 37 and 3.7 MBq (1 resp. 0.1 mCi) 55Co, respectively. Blood samples were withdrawn during 300 min in humans. In seven rats the 55Co-biodistribution was determined by postmortem analysis. The residence time of the liver (critical organ) was determined in rats and humans. Blood partition-data of 55Co were assessed resulting in basic pharmacokinetic data in humans. Based on these kinetic data, radiation dose was calculated using the MIRD protocol. RESULTS: In both the humans and the rat, the liver and bladder retained the highest fractions of 55Co (about 50% resp. 40% of the administered dose). The liver residence time in humans was 8.6 hr. The free fraction 55Co in the human plasma was at maximum 12%. The total-body mean transit time was 152 min. The volume of the central compartment = 2.8 liter and the steady-state distribution volume = 48 liter. CONCLUSION: From these results, according to the WHO recommendations for class II studies, 22.2 MBq (0.6 mCi) 55Co and 14.8 MBq (0.4 mCi) 57Co (excluding any radionuclide contamination) can be used.

Adult↗
PubMed1995

Plasma protein leakage and local secretion of proteins assessed in sputum in asthma and COPD. The effect of inhaled corticosteroids.

Asthma and chronic obstructive pulmonary disease (COPD) are characterized by chronic airway inflammation with cell infiltration, increased plasma exudation and abnormal local secretion of proteins. We have analysed whether sputum differs in this respect between asthma (n = 9) and COPD (n = 9), and whether inflammatory markers in sputum are affected by treatment. In non-smoking asthma patients there was more plasma protein leakage, based on the relative coefficient of excretion Q alpha 2macroglobulin/QIgG (P = 0.03). There was less local secretion of sIgA and lactoferrin than in COPD (P < 0.05). Tryptase was slightly higher in sputum from asthma than from COPD (P < 0.05), whereas eosinophil cationic protein and myeloperoxidase were similar. After treatment with glucocorticosteroids, there was a reduction in the Q alpha 2macroglobulin/Qalbumin (P < 0.015), but no effect was seen on the levels of products from local cells. We conclude that sputum analysis is useful to study the local inflammatory process in asthma and COPD.

Administration, Inhalation↗
PubMed1995

Physical interaction between lung epithelial cells and T lymphocytes.

The present results support a role for epithelial cells in the activation of T cells in an apparent antigen-independent manner. The transient expression of CD25 indicates a short acting T cells activation. Possibly, this event primes T cells to respond swiftly upon antigen-specific stimulation or to synthesize mediators that affect the local milieu. The molecular mechanism of interaction, although not well defined possibly involves LFA3-CD2 interactions. In T cell activation, via LFA3-CD2 interaction, the density of presented LFA3 molecules is critical. With the increase in the level of expression of LFA3 by epithelial cells this critical density may have been reached. However, based on what is known about T cell activation and CD25 expression in particular it is likely that additional signals such as soluble mediators are required for T cell activation by epithelial cells. Whether this mode of activation occurs in vivo remains to be established by studying ex vivo and in situ material. Not much is known about the expression of LFA3 by epithelial cells in vivo, nor about the stimuli that induce the upregulation of LFA3. In preliminary experiments with fluorescence microscopy we found that neither TNF-alpha nor IL-1 beta induce LFA3 in the same fashion as IFN-gamma. In conclusion, T cell activation by epithelial cells could be an important feature in inflammatory and immunological processes in mucosal systems such as the bronchi and deserves further research.

Antigens, CD↗
PubMed1995

Cobalt-55 positron emission tomography in relapsing-progressive multiple sclerosis.

Multiple sclerosis (MS) is an immune-mediated disease of the white matter in the brain that can have a progressive course. However, the progression of relapsing-remitting (RR) MS into relapsing-progressive (RP) MS might represent a more fundamental change in disease activity, i.e. decay of vulnerable neurons and oligodendrocytes. In RP-MS, this may imply that the major loss of brain tissue structure is caused by a combination of demyelination and cellular loss, both of which are likely to cause disability in MS. We used the PET isotope cobalt-55 (Co) as a calcium (Ca) tracer to visualize brain tissue damage, based on the fact that Ca influx is essential in both cell death and T-lymphocyte activation in MS. The aim of this study was to determine whether Co-PET detects any RP-MS lesions and, if so, to assess any correlation with the progression rate (PR) of the disease and with MS lesions as detected by MRI. Seven RP-MS patients (Poser) with EDSS > 4.0 (Kurtzke) and 7 healthy controls underwent MRI (Miller, Barkhof) and Co-PET. Comparison of both image modalities was made by merging. Co-PET lesion frequency was assessed and correlated with the PR of the disease. Co-PET demonstrated significantly more lesions in the MS brain than in the healthy brain, both periventricular and cortical. Every single MRI lesion could be retrieved as a Co-PET lesion. The Co-PET lesion frequency correlated significantly with PR. Our pilot study possibly suggests Co-PET as a tool in estimating disease activity in RP-MS.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1995

Methodological and clinical comparison of the ACS prostate-specific antigen assay and the Tandem-E prostate-specific antigen assay in prostate cancer.

OBJECTIVES: The new ACS prostate-specific antigen (PSA) assay was methodologically and clinically compared with the established Tandem-E PSA assay. We intended to find a possible advantage in primary diagnosis and monitoring the recurrence of prostate cancer due to the additional better recognition of the free PSA form by the ACS PSA assay. METHODS: sera of 51 healthy men, 127 patients with hyperplasia, and 82 untreated patients with prostate cancer were analyzed by means of the Tandem-E PSA assay (Hybritech) and the ACS PSA assay (Ciba Corning). Follow-up was done on 12 cancer patients with recurrences. RESULTS: Both assays correlated very well (r = .98 for all studied men or hyperplasia patients or cancer patients). However, both assays did not yield comparable values: The ACS assay was characterized by nearly doubled values compared with the Tandem-E assay. At 95% specificity versus patients with benign hyperplasia, cutoff values were obtained as follows: 28.8 ng/mL for the ACS PSA assay and 15.2 ng/mL for the Tandem-E assay. At 95% specificity versus hyperplasia patients, we calculated sensitivities of 60% (ACS PSA) and 63% (Tandem-E PSA). Our longitudinal study revealed more prominent slopes for the ACS assay in patients with recurrent cancer disease. However, using either the ACS assay or the Tandem-E assay, the PSA increase started at the same time. In 1 patient, the increasing ACS PSA accelerated 3 months earlier than the increasing Tandem-E PSA did. CONCLUSIONS: The ACS assay has obviously higher PSA levels. The clinician is not familiar with such high PSA levels. The specificity-sensitivity profile nonetheless remains unchanged. If the PSA concentration is measured by the ACS assay, patients who relapse will reveal a more rapid PSA increase. Then, recurrent cancer disease may be detected earlier in some cases.

Adult↗
PubMed1995

Cobalt-57 SPET in relapsing-progressive multiple sclerosis: a pilot study.

Multiple sclerosis (MS) is predominantly a progressive immune-mediated disease of the white matter in the brain. We used single photon emission tomography (SPET) and cobalt-57 (57Co) as a calcium (Ca) analogue to visualize brain tissue damage, based on the fact that Ca influx occurs in both cell death and T-lymphocyte activation in MS. The aim of this study was to determine if 57Co-SPET detects MS lesions and, if so, to compare this with clinical data on the patient. Five MS patients underwent neurological examination including Expanded Disability Status Scale (EDSS) assessment and 57Co-SPET, using a single-headed camera. All available data were compared. The lesions were recognized as areas of increased signal intensity, although the poor count rate did not allow any statistical quantification. A relationship between one 57Co-SPET parameter (cobalt plaque load) and EDSS was demonstrated. In conclusion, this pilot study suggests that 57Co-SPET using a single-headed camera is not an appropriate imaging modality in MS. To obtain a more favourable signal-to-noise ratio, the use of a multi-headed camera, the administration of a higher activity of 57Co and a longer acquisition time are recommended. Validation of this method among a larger group of patients and a comparison with healthy volunteers is needed.

Brain↗
PubMed1995

HLA-DR expression is induced on keratinocytes in delayed hypersensitivity but not in allergen induced late-phase reactions.

In view of increasing evidence suggesting an active immunoregulatory role of the skin keratinocytes and the observation that the differentiation of allergen specific T lymphocytes is critical in the development of allergy, we evaluated epidermal expression of HLA-DR antigen in skin reactions induced with an atopen (house dust mite) and with an non-atopic antigen (Hemocyanin). Two groups of patients with house dust mite (Dermatophagoides pteronyssinus [Der p]) allergy were compared, one group was skin tested with Der p, the other group was immunized and subsequently skin tested with Helix pomatia Hemocyanin (HPH). Biopsy specimens taken at 48 h after the HPH (n = 11) and Der p (n = 11) tests were analysed immunohistologically. Reactions in both groups were comparable in size. Immunohistological analysis showed domination by CD4+ lymphocytes. Expression of HLA-DR antigen by epidermal keratinocytes was observed in six out of 11 of the HPH induced reactions, but in none of the Der p induced reactions. Eosinophils were spotted only throughout the Der p induced reactions, showing a good correlation with the number of CD4 positive lymphocytes. The lack of HLA-DR expression by keratinocytes during the allergen-induced reaction, compared with the Hemocyanin induced reaction can be the result of a difference in cytokine profile of the lymphocytes dominating the dermal infiltrate. On the other hand evidence exists that defective HLA-DR expression by keratinocytes enhances antigen induced lymphocyte activation, and may thus contribute to the development of allergen-specific T-lymphocytes.

Allergens↗
PubMed1995

PCR assay based on DNA coding for 16S rRNA for detection and identification of mycobacteria in clinical samples.

A PCR and a reverse cross blot hybridization assay were developed for the detection and identification of mycobacteria in clinical samples. The PCR amplifies a part of the DNA coding for 16S rRNA with a set of primers that is specific for the genus Mycobacterium and that flanks species-specific sequences within the genes coding for 16S rRNA. The PCR product is analyzed in a reverse cross blot hybridization assay with probes specific for M. tuberculosis complex (pTub1), M. avium (pAvi3), M. intracellulare (pInt5 and pInt7), M. kansasii complex-M. scrofulaceum complex (pKan1), M. xenopi (pXen1), M. fortuitum (pFor1), M. smegmatis (pSme1), and Mycobacterium spp. (pMyc5a). The PCR assay can detect 10 fg of DNA, the equivalent of two mycobacteria. The specificities of the probes were tested with 108 mycobacterial strains (33 species) and 31 nonmycobacterial strains (of 17 genera). The probes pAvi3, pInt5, pInt7, pKan1, pXen1, and pMyc5a were specific. With probes pTub1, pFor1, and pSme1, slight cross hybridization occurred. However, the mycobacterial strains from which the cross-hybridizing PCR products were derived belonged to nonpathogenic or nonopportunistic species which do not occur in clinical samples. The test was used on 31 different clinical specimens obtained from patients suspected of having mycobacterial disease, including a patient with a double mycobacterial infection. The samples included sputum, bronchoalveolar lavage, tissue biopsy samples, cerebrospinal fluid, pus, peritoneal fluid, pleural fluid, and blood. The results of the PCR assay agreed with those of conventional identification methods or with clinical data, showing that the test can be used for the direct and rapid detection and identification of mycobacteria in clinical samples.

Bacteriological Techniques↗
PubMed1995

Predisposing conditions to bacterial infections in chronic obstructive pulmonary disease.

In normal airways, invasion of small numbers of pathogenic bacteria will not give rise to injury or local colonization. In chronic obstructive pulmonary disease, however, local conditions are changed, which may impair local defense systems and facilitate infection. These include: (1) factors promoting bacterial adherence and growth like the observed damaged airway epithelium in chronic bronchitis. The consequent changes in the composition of the epithelial lining fluid and impaired mucociliary clearance may be the most important pathophysiologic airway sequele in this respect; (2) aggravating generalized airway obstruction including mucus secretion, increase in mucus viscosity, and proliferation of submucosal smooth muscles, resulting in significant changes in airway geometry. This may change local conditions dramatically and so sustain factors promoting bacterial infections; (3) subversion of normally protective defense mechanisms into damaging host tissue at the mucosal level. Activated epithelial cell layers induce increased submucosal vascular leakage, edema, and inflammatory cell infiltration with subsequent tissue injury by locally produced cell products like free elastase. Specific bacterial products but also generally produced bacterial endotoxins may induce a local immune response resulting in the local production of high concentrations of antibodies and an invasion of specific effector cells. The role of these reactive cells or proteins may even be a primary one, in that they attack on (cellular) proteins, which increase their susceptibility for dysfunction in the defense line. For the clinicians, the new insights in the role of these aggravating factors in the development of recurrent bacterial airway infections in chronic bronchitis may be of major importance.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Adhesion↗
PubMed1995

Virulence factors in the colonization and persistence of bacteria in the airways.

Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa are commonly isolated from sputum specimens of patients with lower respiratory tract infections. Haemophilus influenzae, S. pneumoniae, and M. catarrhalis have several pathogenic properties in common. These bacteria are able to interact with mucus, to exert ciliotoxic activity, to adhere to bronchial epithelial cells, and to invade airway epithelium. Haemophilus influenzae and S. pneumoniae strains persist for many months in the respiratory tract of patients with chronic obstructive pulmonary disease (COPD), despite the specific antibodies present in serum and sputum against the persistent strain. Especially during exacerbations persistent strains with changes in their antigenic composition are isolated. Among H. influenzae strains, the antigenic characteristics of the outer membrane protein composition vary. Variation in S. pneumoniae occurs in capsular polysaccharides, the major immunogens of this bacterium. Such variations affect the efficacy of the antibody-mediated defense mechanisms against the bacteria. Between exacerbations, particularly H. influenzae, S. pneumoniae strains are recovered from the sputum of patients with COPD. Recovery may continue for periods up to 2 yr, although not continuously. Besides ineffective antibody-mediated defense mechanisms, it is likely that hiding of the bacteria in tissue contributes to the persistence of these bacteria in patients with COPD.

Bacterial Infections↗
PubMed1995

Inhaled budesonide in pulmonary sarcoidosis: a double-blind, placebo-controlled study. Dutch Study Group on Pulmonary Sarcoidosis.

In a double-blind, placebo-controlled study, we assessed the efficacy of inhaled budesonide on the course of newly diagnosed pulmonary sarcoidosis and whether budesonide treatment could postpone oral corticosteroid treatment. We evaluated: 1) symptoms; 2) chest radiography; 3) angiotensin-converting enzyme (ACE) in serum; and 4) lung function. Patients with histologically confirmed pulmonary sarcoidosis with chest radiographic stages I, II or III, and with an abnormal lung function (inspiratory vital capacity (IVC) < 79% of predicted or transfer factor of the lungs for carbon monoxide (TL,CO) < 77% pred) were included. Patients with radiographic stage II or III but with normal lung function were included when more than 20% of the total cell population in bronchoalveolar lavage fluid (BALF) was lymphocytes. Forty seven patients received placebo or budesonide (1.2 mg) once daily via a Nebuhaler for 6 months, followed by 6 months without treatment. Based on predetermined criteria, 11 patients were excluded during the blind treatment period as they needed oral prednisone: seven (28%) patients in the placebo group (n = 25) and four (18%) patients in the budesonide group (n = 22). Patient's Global Clinical Impression (GCI) score showed a significant difference in favour of budesonide. IVC showed a significant difference of 7.9% predicted between the two groups during the active treatment period. This difference persisted during follow-up, when the difference was 9.4% pred. TL,CO remained nearly unchanged over time, with no difference between the groups. Improvements in chest radiographic appearance and changes in serum ACE were similar for the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1994

Characterization of cat dander-specific T lymphocytes from atopic patients.

Fel d I, the major cat dander allergen, is recognized by serum IgE of more than 80% of all cat-allergic patients. Because IgE synthesis by B lymphocytes is under the control of T lymphocytes, we studied the specificity and lymphokine production profiles of cat dander-specific T lymphocytes. Polyclonal cat dander-specific T cell lines were found to react with purified Fel d I, but not with cat albumin, the only other characterized cat allergen. Similarly, within a panel of CD4+ T lymphocyte clones (TLC) that was generated from these cat dander-specific T cell lines, 5 of 16 TLC were found to react with Fel d I, and 0 of 16 with cat albumin. The remaining 11 TLC were shown to recognize at least two different proteins. In general, the TLC had a high IL-4/IFN-gamma production ratio, and could recognize the cat dander extract in an HLA-DR, HLA-DQ, or HLA-DP restricted manner. In addition, five distinct T cell epitopes of Fel d I were identified by using a panel of overlapping synthetic peptides of both chains of Fel d I. The data presented here indicate that, even though multiple proteins in cat dander extract are recognized by T lymphocytes of allergic patients, Fel d I, the major IgE binding allergen, is also important in T cell activation. The fact that the cat-specific TLC are Th2-like indicates that these cells may play an important role in the pathophysiology of allergic responses to cat allergens. However, the diversity of HLA-class II restriction of cat dander- and Fel d I-specific TLC and the presence of multiple T cell epitopes in the allergen may complicate future immunotherapies.

Amino Acid Sequence↗
PubMed1994

Antigenic drift of non-encapsulated Haemophilus influenzae major outer membrane protein P2 in patients with chronic bronchitis is caused by point mutations.

The sequence of the gene encoding major outer membrane protein (MOMP) P2 of antigenic variants of non-encapsulated Haemophilus influenzae isolated from persistently infected chronic bronchitis patients was analysed. Antigenic drift was shown to result from single base changes in the P2 gene, all generating amino acid changes in the surface-exposed loops of MOMP P2, predominantly in loop 6. Similar single base changes were observed in H. influenzae persistently present in a subcutaneous cage implanted in rabbits, as well as in a spontaneous H. influenzae mutant that had survived MOMP P2 specific monoclonal-antibody-dependent bactericidal killing in vitro. We hypothesize that accumulation of point mutations under the selection pressure of immunity is a mechanism of antigenic drift of a surface-exposed protein during persistent H. influenzae infection.

Amino Acid Sequence↗
PubMed1994

Expression of activation markers by human lung T cells after adherence to lung epithelial cells.

Both increased T cell numbers and their increased activation state have implicated an important role for T cells in chronic inflammatory reactions seen in the airways of (allergic) asthmatics. Airway epithelial cells are frequently exposed to stimuli that cause the release of mediators and the expression of cell adhesion molecules. We have examined whether human airway epithelial cells can activate lung-derived T cells. Clonal lung T cells showed an increased adherence to transformed airway epithelial cells that had been exposed previously for 2 h to human recombinant interferon-gamma (IFN-gamma; 100 U/ml). After an additional 16-24 h of culturing in the absence or presence of epithelial cells, T cells expressed increased levels of both the alpha-chain of the interleukin-2 receptor (IL-2R, CD25) and the transferrin receptor (CD71), both markers of T cell activation. T cells apparently activated by epithelial cells, however, did not produce IFN-gamma or IL-4 nor showed an increased proliferation on the addition of IL-2 (5-50 U/ml). The induced adherence to and the activation of T cells by epithelial cells is mediated largely by CD2 and its ligand lymphocyte functional antigen-3, a pathway known to up- and downregulate T cell functions.

Antigens, CD↗