Biomedical subjects

W Hijmans

Publications and source records attributed to W Hijmans.

At least 37 records · Page 2Linked to original sources

PubMed1985

Light and electron microscopic studies of the rat hyalocyte after perfusion fixation.

The characteristic morphology of a not intentionally stimulated hyalocyte is described, using TEM and perfusion fixation. The best results were obtained by retrograde perfusion via the abdominal aorta with a glutaraldehyde- and formaldehyde-containing fixative. The cells, situated in the cortical area of the vitreous body, show mostly an indented nucleus, primary and secondary lysosomes, mitochondria, cisterna, clusters of free ribosomes and a Golgi apparatus. Bristle-coated micropinocytotic vesicles can also be distinguished and in some cells a centriole is visible. Sometimes the cells show many cytoplasmic protuberances. Morphologically the majority of those cells can be considered as resting macrophages.

Animals↗

PubMed1985

Subpopulations of mononuclear cells in ageing: expansion of the null cell compartment and decrease in the number of T and B cells in human blood.

Study of the immune system in ageing has yielded conflicting results. These controversies are mainly due to the selection of the subjects studied. We investigated the mononuclear cell subpopulations in the peripheral blood of subjects fulfilling strict admission criteria meant to exclude persons with diseases that influence the immune system. These criteria are described in the SENIEUR protocol devised by a working group in the framework of EURAGE, the Concerted Action Programme on Ageing of the European Community. We compared two groups of volunteers aged 25-34 years, and 75-84 years. Mononuclear cells were investigated by two-wavelength immunofluorescence combined with phase-contrast microscopy. We found a striking increase in the number of 'null' cells (non-T, non-B, non-monocyte) in the blood of the aged persons. The number of T cells was decreased, especially in the suppressor/cytotoxic subset. The number of B cells was slightly, but significantly, decreased; the number of monocytes did not change. The changes in these cell populations may be related to functional changes, and their quantification could be used to monitor attempts to reconstitute the immune defects in ageing. These findings can also serve as reference values in the study of aged persons not fulfilling the SENIEUR criteria, which, in turn, can contribute to the dissection of the influence of disease versus age on the immune system.

Adult↗

PubMed1985

[Problems of aging in China].

A WHO consultancy to the 'National Seminar on Geriatrics' in Beijing provided an opportunity to get some ideas about the problems of ageing in China. Since 1949 life expectancy has doubled and it has been estimated that between now and the end of the century the 65+ group will double to a total of approximately 100 million people. This will be the fastest growing ageing population in history. With more than 1000 million inhabitants China is the largest country in the world and also because of epidemiological facilities it offers unique opportunities to study for instance maximum life-span. Results sofar support the view that this will not exceed the generally accepted figure of 120 years. Institutional care is limited, but this is at least partly offset by the structure of society, having the family as the central unit. Preventive medicine scores high and one should hope that it will contribute to geriatrics, as it has contributed to other parts of medicine.

Aged↗

PubMed1984

Admission criteria for immunogerontological studies in man: the SENIEUR protocol.

Immunogerontological studies in man have often led to conflicting results. One of the main reasons is the selection of the subjects to be studied. Admission criteria such as "apparently healthy" or "without overt disease" seem insufficient to exclude underlying disease which might influence the immune system and thereby the results. In an attempt to solve this problem, the SENIEUR protocol described in this paper was developed by a working party in the framework of the EURAGE Concerted Action Programme on Ageing of the European Community. This protocol establishes strict admission criteria for immunogerontological studies in man based on clinical information and laboratory data, and it sets limits to pharmacological interference. The use of this protocol will lead to standardization between centers and also to a closer study of the influence of age as such on the immune system. These findings in the immunologically "optimally aged" can also serve as reference values for immunogerontological studies in subjects who do not meet the SENIEUR criteria. In this way the use of this protocol can contribute to the dissection of the influence of disease versus ageing on the immune system.

Adult↗

PubMed1984

Autoantibodies in highly aged humans.

The presence of 14 different autoantibodies was determined in 65 persons, aged 95 years and older, without overt disease. The prevalence of positive anti-immunoglobulin latex tests, of autoantibodies against nuclear components and against thyroid microsomes was significantly increased. This selective increase of autoantibodies of low titre and without cluster formation is considered to be the result of a loss of control within the immune system due to ageing, rather than as a sign of latent disease.

Aged↗

PubMed1984

Intracellular inclusion bodies in 14 patients with B cell lymphoproliferative disorders.

Two types of intracytoplasmic inclusion were detected by immunofluorescence microscopy in 12 patients with chronic lymphocytic leukaemia and two patients with a leukaemic phase of well differentiated lymphocytic lymphoma. Further analysis with light- and electron microscopy, showed that most inclusion bodies were rod-like crystalline structures. However, in three patients they consisted of amorphous vesicular precipitates. Immunological studies revealed the presence of immunoglobulins of the same class and type at the cell surface as well as in the inclusion bodies. The monoclonal immunoglobulins were all of lambda type except in two cases. The origin of immunoglobulin inclusion bodies in B cell malignancies is discussed in relation to published data and our own observation in one patient followed during treatment.

Aged↗

PubMed1984

Hairy cell leukemia: its place among the chronic B cell leukemias.

Hairy cell leukemia is a chronic B cell leukemia. The presence of surface Ig (SIg) of gamma or multiple isotypes on the cells locates HCL at a rather mature stage of B cell differentiation. The reactivity of HC with McAb is in accordance with this concept (T65-, OKM1+, FMC7+, BA-1-). To relate HCL to other chronic B cell leukemias, a morphologic classification was developed that distinguishes, besides HCL, five subtypes of chronic B cell leukemia. CLL showed weak staining for SIg of mu +/- delta class. The phenotype with McAb was T65+, OKM1-, FMC7-, BA-1+. Prolymphocytic transformation of CLL had essentially the same membrane phenotype. LPL often had brighter SIg of mu +/- delta class with gamma or multiple isotypes in about half of the cases. McAb gave a T65-or+, OKM1-or+, FMC7-or+, BA-1+ phenotype. The same surface-marker profile was found in CL. Finally, PLL showed bright SIg of gamma or multiple isotypes in the majority of cases and reactivity with McAb according to a T65-or+, OKM1+, FMC7+, BA-1+ pattern. The various immunologic phenotypes of the morphologic subtypes showed a considerable overlap. The various chronic B cell leukemias should be located in the scheme of B cell differentiation in the sequence CLL-LPL/CL-PLL-HCL.

Antibodies, Monoclonal↗

PubMed1984

Surface bound or cytoplasmic immunoglobulins: interpretation of the immunofluorescence observed in cytocentrifuge slides of human lymphocytes.

Results of immunofluorescence observations in the study of normal and malignant blood lymphocytes are described. Data which support the proposition that most membrane bound immunoglobulin molecules are stable enough to remain intact during cytocentrifuge slide preparation are presented. Therefore not all positive cells in a fixed cytocentrifuge slide should be considered as containing cytoplasmic immunoglobulins. A correct interpretation is essential because of its bearing on our concepts of B lymphocyte differentiation.

B-Lymphocytes↗

PubMed1984

Prognostic significance of immunologic phenotype in hairy cell leukemia.

Hairy cell leukemia (HCL) is a usually chronic B cell lymphoproliferative disorder. To evaluate the prognostic significance of the various heavy and light chain determinants of the surface immunoglobulins (slg), we analyzed the clinical data and immunologic phenotype of 64 patients with HCL. Sixty-two of the 64 patients showed slg, which was invariably of only one light chain type (kappa 33, lambda 29). The actuarial survival of the cases expressing kappa-light chains was significantly better than those with lambda-light chains (p less than 0.002). This difference persisted when only cases with gamma or alpha gamma heavy chains were considered. No differences between the kappa and lambda-subgroups were discovered with respect to parameters of clinical importance. The various heavy chain classes of slg did not correlate significantly with the survival time. These results suggest that the immunologic phenotype, in particular the light chain type, may be a prognostic factor in patients with HCL.

Adult↗

PubMed1983

[Immunity in the aged].

The function of most organs decline in function of ageing and the immune system forms no exception. It has been shown that atrophy of the thymus plays a central role in these diminished immune reactions and also in two other immunogerontological phenomena: auto-antibodies and idiopathic paraproteinaemia. Already at this stage of our knowledge the information is of practical value in geriatric medicine. Immunological research can also contribute to our understanding of diseases of ageing and further our insight into the process of ageing itself.

Aged↗

PubMed1982

Cell markers in hairy cell leukemia studied in cells from 51 patients.

To determine the maturation arrest of the neoplastic cells of hairy-cell leukemia (HCL) and the spectrum of the surface markers on these cells, a series of 51 patients with this disease was studied. The cells of all but two of the patients showed monoclonal surface Ig with respect to light chains. In about one-third of the cases, only gamma heavy chain determinants were present on the cells; the majority carried multiple heavy chain determinants as documented by the application of different fluorochromes. Two patients each showed two different clones of cells, both of the same light chain type. In one of these two patients, two paraproteins were present in the serum. Intracytoplasmic Ig was found in only 4 of 39 cases, in all instances being IgM. All cases studied concerned cells with FclgG receptors; however, the density of this receptor varied. FcIgM receptors also showed a spectrum of density, with some cases showing very few FcIgM-positive cells. Receptors C3 were not observed on the hairy cells. Serum immunoglobulin levels were normal or increased. Paraproteins were found in the sera of 4 of 38 patients. These data suggest that HCL is a neoplasm of B lymphocytes. The neoplastic cells are probably arrested at a more mature stage than the cells of chronic lymphocytic leukemia. The multiple isotypes on the cells indicate a block at the "switch" phase from the small micro-carrying lymphocyte to the larger Ig-producing lymphocyte or plasma cell.

Adult↗

PubMed1981

The specificity of commercial conjugates to human immunoglobulins: results of performance tests on monoclonal and polyclonal plasma cells and lymphocytes.

The activity and the specificity of 29 fluorochrome conjugated antisera against human immunoglobulin heavy and light chains were evaluated by performance testing with the direct technique of immunofluorescence using plasma cells and lymphocytes as biological substrates. Fifteen conjugates gave satisfactory results in the detection and classification of cytoplasmic and surface bound immunoglobulins and were therefore considered specific. Fourteen conjugates did not meet the required standards. The usefulness of the biological substrates for quality control tests is discussed.

Animals↗

PubMed1981

Regulation of the "spontaneous' (background) immunoglobulin synthesis.

The number of mature cytoplasmic immunoglobulin containing cells (C-Ig cells) in various lymphoid organs of the mouse was studied as a function of antigenic load and the presence of T cells. Both antigen and T-cell deprivation decreased the number of C-Ig cells (plasma blasts and plasma cells). The absolute C-Ig cell numbers were minimal in germfree nude mice, intermediate in specific pathogen-free (SPF) nude mice and in germ-free thymus-bearing mice, and the largest in SPF thymus-bearing mice. The bone marrow was the organ where this picture was most strikingly examplified. In germfree C3H mice raised on a synthetic diet the bone marrow of 3 out of 4 mice tested did not show any C-Ig cell. None of them had C-Ig cells in the mesenteric lymph nodes. The Ig class distribution of the C-Ig cells and the incidence of C-Ig cells positive for more than one Ig heavy-chain isotype ("double producers') were also highly dependent upon the antigenic load and the presence of T cells. C-IgM cells were well represented in all groups of mice. Appreciable numbers of C-IgA cells were only found in SPF thymus-bearing mice. The absolute number, but not the relative number, of C-IgG cells followed the same pattern. The percentages of double producers in the various lymphoid organs were largest in germfree nude mice, intermediate in SPF nude mice and in germfree thymus-bearing mice, and minimal in SPF thymus-bearing mice. From these studies we conclude that the background synthesis of IgG and IgA in not intentionally immunized mice is virtually completely dependent on stimulation of the immune system by external antigens, in contrast to the production of IgM.

Animals↗

PubMed1981

Multiple heavy chain isotypes on the membrane of the small B lymphocytes in human blood.

Small lymphocytes from adult human blood were examined for the presence of membrane-associated alpha, gamma, delta and mu Ig isotypes by means of a direct immunofluorescence technique. Since less than 10% of the small lymphocytes in blood are B cells as defined by positive reactivity with an anti-Fab conjugate, our experiments were performed on a T cell-depleted fraction in which about 80% of the small lymphocytes were B cells. With the two-wavelength immunofluorescence method, all of the double-isotype combinations were found. The percentage of cells bearing more than two isotypes was deduced. The delta mu and the alpha delta mu combinations were the most common, as previously found on tonsillar lymphocytes. In contrast with the tonsils, no lymphocytes bearing only delta were observed and the proportions of alpha gamma- and alpha gamma mu-bearing lymphocytes were very small. The presence of lymphocytes bearing four isotypes could practically be excluded.

Adult↗

PubMed1981

The bone marrow: the major source of serum immunoglobulins, but still a neglected site of antibody formation.

Immunoglobulin (Ig) secreting cells occur in all lymphoid tissues, including the bone marrow (BM). There are important differences between the various organs with respect to their number of Ig-secreting cells and the heavy chain isotype distribution of the secreted Igs. Furthermore, both distribution patterns depend on age. Early in life most Ig-secreting cells are localized in spleen and lymph nodes. In adults, however, the majority of all Ig-secreting cells of the individual are localized in the BM. Immunization can lead to the appearance of substantial numbers of antibody-forming cells in BM. The kinetics of the BM response are different from the response in the peripheral lymphoid tissues. Shortly after immunization most antibody-forming cells occur in the peripheral lymphoid tissues, but later on, especially during secondary type responses, most antibody-forming cells are localized in the BM. Apparently, antibody formation is regulated in such a way that peripheral lymphoid tissues respond rapidly, but only for a short period, whereas the BM response starts slowly, but takes care of a long-lasting massive production of antibodies to antigens which repeatedly challenge the organism.

Age Factors↗

PubMed1980

Presence of multiple isotypes on the surface of human tonsillar lymphocytes.

Formaldehyde-fixed small lymphocytes from human tonsils were investigated for the presence of the Ig heavy chain class isotypes alpha, gamma, delta and mu on their membranes by means of a direct immunofluorescence technique. About 50% of the small lymphocytes were defined as B cells with an anti-Fab antiserum. Most of the B lymphocytes carried more than one isotype on their membrane, and all combinations of two isotypes were observed. The existence of three or four isotypes on the membrane of individual lymphocytes was deduced. The sIgD, sIgM and sIgA, sIgD, sIgM combinations were the most common. The isotypes were present as separate molecules since they showed independent distribution patients undeesent as separate molecules since they showed independent distribution patterns under capping conditions.

Cell Membrane↗

PubMed1980

Identification of mononuclear cells in human blood. I. Qualitative and quantitative data on surface markers after formaldehyde fixation of the cells.

The technical details of a fixation procedure with formaldehyde which was applied in a direct membrane immunofluorescence technique to mononuclear cells from normal human blood are described. After separation of the cells with Ficoll--Isopaque according to Böyum (1963) they were washed and fixed with 0 . 04% formaldehyde in PBS for 10 min and washed again. This cell suspension can be stored at 4 degrees C for at least 24 hr and the slides prepared from them at -20 degrees C for at least some months. In practice, this fixation procedure not only appeared to be effective in the preservation of cells but also showed a number of additional advantages, such as the short handling period, including the fixation procedure and the avoidance of loss of cells. Moreover, true B lymphocytes, as defined by the synthesis of immunoglobulins and the incorporation of these molecules into their cell membrane, are recognized convincingly.

Blood Preservation↗

PubMed1980

Identification of mononuclear cells in human blood. II. Evaluation of morphological and immunological aspects of native and formaldehyde-fixed cell populations.

The presence of surface-associated immunoglobulins and Fc receptors on mononuclear cells from normal human blood was investigated by the direct immunofluorescence technique combined with phase-contrast microscopy. Formaldehyde-fixed cells were compared to unfixed cells and to cells preincubated at 37 degrees C. In the unfixed samples a separate population which showed Fc receptors in an immunofluorescence technique using a labelled antigen--antibody complex was detected. This cell population showed an atypical, i.e. not clearly membrane-associated, pattern of fluorescence with anti-Fab conjugates. This interaction most probably is due to autologous IgG molecules taken up by these cells from the donor serum. Using phase-contrast microscopy, these cells were morphologically distinct from lymphocytes and mature monocytes. They will be referred to as 'undefined mononuclear cells' (UMC). After formaldehyde fixation or preincubation at 37 degrees C the interaction of the UMC with anti-Fab conjugates could no longer be demonstrated. Mature monocytes show the same atypical fluorescence pattern with anti-Fab conjugates, but in contrast to the UMC the interaction persists after formaldehyde fixation or preincubation at 37 degrees C. No evidence was found for passive uptake of labelled IgG from conjugates by any mononuclear cell F(ab')2 fragments of IgG from antisera gave results similar to those obtained with intact IgG fractions. The morphology of the different cell subpopulations is described and their relative numbers in normal blood are given. Formaldehyde fixation proved to be a simple and useful procedure, especially for the determination of the number of B lymphocytes, because the Fc receptor of the undefined mononuclear cell does not give rise to confusion.

Antigen-Antibody Complex↗