Biomedical subjects

P J van Munster

Publications and source records attributed to P J van Munster.

At least 19 recordsLinked to original sources

PubMed1991

Familial selective IgA deficiency with circulating anti-IgA antibodies: a distinct group of patients?

Two families were investigated in which the mothers had selective IgA deficiency and circulating class-specific anti-IgA antibodies. Both gave birth to two children who were found to be IgA deficient. Three of these children developed anti-IgA antibodies before puberty. In vitro immunoglobulin production studies performed in the children of both families revealed an IgA B cell defect combined with IgA-specific excessive T suppressor function in all four. The mechanisms by which transplacental passage of maternal anti-IgA antibodies could have interfered with the developing IgA system in the offspring are discussed.

Adult↗

PubMed1989

Screening for microalbuminuria in patients with diabetes mellitus: frozen storage of urine samples decreases their albumin content.

The influence of storage on urinary albumin concentration was prospectively studied with use of overnight urine specimens (Albustix negative) from 73 diabetic patients. From each urine sample four aliquots were taken. One was stored at 4 degrees C and assayed within two weeks, the other three were stored at -20 degrees C and assayed within two weeks and after two and six months. Albumin concentration was measured with laser immunonephelometry. The detection limit, 1 mg/L, suffices for the screening of diabetic patients for microalbuminuria. After storage for two and six months at -20 degrees C, significantly lower albumin concentrations were found. The difference was mainly caused by lower concentrations found in urine samples in which a precipitate had formed, which was the case in 22 and 25 samples, respectively. Thus, freezing of urine samples for determination of low concentrations of albumin may yield falsely low results. Urine samples are best stored at 4 degrees C and assayed within two weeks.

Albuminuria↗

PubMed1988

Prednisolone can increase glomerular permeability to proteins in nephrotic syndrome.

In patients with a nephrotic syndrome administration of prednisolone causes an increase of proteinuria. To elucidate the mechanism of this effect we have studied the acute proteinuric effect of prednisolone, 125 to 150 mg intravenously, in nine patients (7 M, 2F) with a nephrotic syndrome. Mean age (+/- SD) of the patients was 53 +/- 6 years, mean endogenous creatinine clearance 104 +/- 30 ml/min, and mean proteinuria 7.7 +/- 3.0 g/24 hr. After administration of prednisolone, urinary total protein excretion rose in all patients from a mean (+/- SEM) of 4.89 +/- 0.59 mg/min before to 9.09 +/- 0.99 mg/min at five hours after administration (P less than 0.01). Glomerular filtration rate (inulin clearance), effective renal plasma flow (PAH clearance), and filtration fraction did not change significantly. The increases of urinary excretion of albumin (median %: +92%), IgG (median %: +88%), and transferrin (median %: +76%) were comparable and correlated significantly. Urinary excretion of beta 2-microglobulin did not change significantly however. We conclude that intravenous administration of prednisolone to patients with a nephrotic syndrome causes an increase in urinary protein excretion rate which cannot be explained by changes in renal hemodynamics or tubular protein reabsorption, and which therefore must be the result of a change in glomerular permselectivity characteristics.

Capillary Permeability↗

PubMed1988

[The significance of determining humoral defense factors: Ig isotypes, specific antibodies and complement].

The diagnosis of an immunodeficiency is made after detailed clinical and laboratory investigations. To guide these investigations the Dutch Working Group on Immunodeficiencies had made a protocol for evaluating the functioning of the immune system of patients. The protocol is based on the report 'Immunodeficiency' from a WHO scientific group. This paper discusses the value of laboratory investigations on the following aspects of the immune system: immunoglobulins and their subclasses, primary and secondary antibody responses in vivo, and the complement system. The evaluation of these components of the defense system can firmly establish possibly occurring severe immunodeficiency states. Some cases of chronic and/or recurrent infections, however, remain enigmas that have to be resolved by future investigations on the interactions of infectious agents with the immune system.

Antibodies↗

PubMed1988

[Immunodeficiency and chromosome instability].

In this paper, a survey is given of the immunological disturbances in some chromosome instability disorders (e.g. Bloom syndrome, ataxia teleangiectasia and Nijmegen Breakage syndrome). Further, the clinical symptoms and the diagnostic approach will be discussed.

Antibody Formation↗

PubMed1987

Enrichment of subgingival microflora on human serum leading to accumulation of Bacteroides species, Peptostreptococci and Fusobacteria.

This study was undertaken to identify ecological factors that favour opportunistic pathogenic species in the subgingival microflora. In a first approach, human serum as a substitute for gingival exudate, was used for batch-wise enrichment of subgingival plaque. The microflora resulting after 5-6 enrichment steps consisted of black-pigmented and non-black-pigmented Bacteroides species, Peptostreptococcus micros and Fusobacterium nucleatum as the main organisms. It is noted that the same group of species was found to be enriched independent upon the origin of the subgingival plaque sample. It was suggested that these organisms are favoured by the increased flow of gingival exudate during inflammation. The consortium of organisms was capable of selective degradation of serum (glyco-)proteins. Four different types of degradation occurred. After a prolonged period of growth complete degradation of immunoglobulins, haptoglobin, transferrin and complement C3c was observed. Partial degradation of immunoglobulins, haptoglobin, transferrin, albumin, alpha 1-antitrypsin and complement C3c and C4 was generally observed after 48 h of growth. Besides, immunoglobulin protease activity yielding Fc and Fab fragments was found. The consortium was also capable of consuming carbohydrate side-chains as indicated by an altered electrophoretic mobility of the serum glycoproteins.

Bacteroides↗

PubMed1986

Posttraumatic complications and inflammatory mediators.

In a series of 71 patients with trauma, we measured weekly the blood levels of a number of complement proteins and activation products. We also measured the following: leukocytes, platelets, granulocyte enzyme elastase, alpha 1-antitrypsin, total protein, albumin, haptoglobin, and fibronectin. The intensity of complement activation and the blood levels of elastase correlated with the following factors: injury severity (especially the severity of limb injury), development of adult respiratory distress syndrome, development and severity of multiple organ failure, and probability of a fatal outcome. The plasma elastase level seemed to be the best predictor of adult respiratory distress syndrome and the best correlate of injury severity and multiple organ failure severity. Our findings support the hypothesis that posttraumatic activation of the complement system leads to activation of granulocytes, followed by microvascular injury and finally by organ failure.

Adolescent↗

PubMed1986

Nephelometry of the kappa/lambda light-chain ratio in serum of normal and diseased children.

We determined, immunonephelometrically, the ratio between the two types of light chains of immunoglobulins, kappa and lambda, in serum of 94 children, ages 0.4 to 14 years, with no manifest immunological disorders. Children with an abnormal protein pattern by immunoelectrophoresis show other values for this ratio than do children in this reference group. We also determined the ratios for children with IgA deficiency (I), juvenile rheumatic arthritis (II), and acute lymphoblastic leukemia (III). Children with I show the same kappa/lambda ratios as for the children in the reference group. Children with II also show the same mean kappa/lambda ratios, but a significantly wider range of ratios. In children with III, the ratio during chemotherapy is slightly depressed, significantly lower than after cessation of therapy. All groups--healthy children and patients--show an increase in kappa-chain-bearing immunoglobulins with age, but the concentration of lambda-chain-bearing immunoglobulins remains relatively constant.

Adolescent↗

PubMed1986

Immunological investigations in individuals with selective IgA deficiency.

Concentrations of IgG2, IgG4 and IgE were low in 16, 24 and 20% of 25 persons with selective IgA deficiency. Fifty-two per cent had IgD concentrations below 5 iu/ml. Trends for association between any of these parameters and the presence of clinical symptoms were not significant. All patients, except one, had normal amounts of Ig-bearing lymphocytes in the blood. IgG1 antibodies against casein were increased in titre and frequency, whereas IgG4 antibodies were normal. Similar results were found in other sera from persons with selective IgA deficiency.

Adolescent↗

PubMed1984

Radioimmunoassay (RIA) for prostatic acid phosphatase in patients with prostatic carcinoma.

In recent years radioimmunological measurements of prostatic acid phosphatase have been proposed for the diagnosis, follow-up and prognosis of prostatic carcinoma. The possibility of screening male populations at risk has even been suggested. The present paper deals with the current position of this method. We studied the specificity and sensitivity of the radioimmunoassay (RIA) for prostatic acid phosphatase in three groups of patients: a normal population, patients with benign prostatic hyperplasia, and patients with untreated prostatic carcinoma. The conclusions of this study are that the RIA is a specific method but the sensitivity is much too low to use the RIA for diagnosis and screening of patients. Comparison with the enzymatic method indicates that under good laboratory conditions the latter is preferable except for patients with metastatic disease and normal enzymatic acid phosphatases.

Acid Phosphatase↗

PubMed1984

Effects of angiotensin II blockade in the canine puppy under different salt-intake.

The objective of this study was to investigate the relationship between the high activity of the renin-angiotensin-aldosterone system (RAAS) and the control of blood pressure and aldosterone in the canine puppy. The effect of the angiotensin II analog saralasin on arterial pressure (MAP), plasma renin activity (PRA), plasma renin concentration (PRC), and aldosterone (PA) was studied in unanesthetized normal, salt-loaded and salt-depleted puppies aged 9 to 30 days. Salt-loading was performed by daily intraperitoneal administration of 10 mEq sodium/kg body weight for 5 days and salt-depletion by furosemide injections. Saralasin infusion, 6 micrograms/kg/min, during 60 min significantly decreased MAP and increased PRC not only in salt-depleted puppies, as has been observed in adult salt-depleted dogs, but also in normal puppies (mean fall, 6.6 mm Hg). Although any developmental changes in the RAAS and MAP and in their relationship could not be ascertained, the fall in MAP during saralasin in normal puppies was significantly correlated to presaralasin renin values (r = 0.76, P less than 0.01, N = 11). PA did not change in both groups of puppies. In salt-loaded puppies saralasin caused no change of MAP, PRC, and PA. We conclude that the high renin levels at young age contribute to the basal arterial pressure in puppies.

Aldosterone↗

PubMed1984

Antibody responses in vivo in chromosome instability syndromes with immunodeficiency.

The primary IgG, IgM and IgA antibody responses to Helix pommatia haemocyanin (HPH) were defective in patients with ataxia telangiectasia (AT) and Nijmegen breakage syndrome (NBS). The results in patients with Bloom's syndrome (BS) were heterogeneous, but all showed abnormal kinetics of the IgG response. The secondary response to diphtheria, tetanus and polio vaccine was normal in patients with AT and BS, but disturbed in the patients with NBS. The abnormalities of antibody response of AT and NBS are similar, although more profound in NBS; BS is different.

Adolescent↗

PubMed1983

Growth pattern of tumor xenografts in Wistar rats after treatment with cyclophosphamide, total lymphoid irradiation and/or cyclosporin A.

Wistar rats treated with cyclophosphamide, total lymphoid irradiation (TLI), and/or cyclosporin A (CSA) develop a state of immune suppression permitting the growth of tumor xenografts. Experiments were carried out on this newly developed model to investigate the growth patterns of a mouse osteosarcoma and a human colon adenocarcinoma. The combination of cyclophosphamide and CSA permitted a limited period of growth of the mouse osteosarcoma with a tumor take rate of 66%. No takes were observed with the human adenocarcinoma. The combination of cyclophosphamide and TLI resulted in a period of immunosuppression followed by recovery of the immune status. During the period of immunosuppression, tumor xenografts showed a 100% take rate. The most efficient immunosuppression was achieved by a combination of cyclophosphamide, TLI and CSA administered on alternate days. Wistar rats subjected to this treatment showed prolonged tolerance to mouse osteosarcoma and human adenocarcinoma xenografts. There was no alteration in the tumor doubling time or histological morphology of the xenografts in the adapted host as compared with those in the donor tumors. The tumor growth curve showed a pattern of initial growth, a period of stagnation, followed by a steady but slower growth phase. The significance of the results and the advantages of the rat model described in this paper for human tumor xenotransplantation are discussed.

Adenocarcinoma↗

PubMed1983

The primary immune response in patients with selective IgA deficiency.

The primary immune response in vivo of 20 patients with selective IgA deficiency was studied and compared to controls. The primary cellular immune response tested by dinitrochlorobenzene (DNCB) was decreased in many patients. The primary humoral immune response was elicited by immunization with the test immunogen Helix pomatia haemocyanin (HPH). Using a direct ELISA technique antibodies against HPH of the IgA, IgG and IgM class were measured. Two weeks after immunization no response of IgA anti-HPH was seen except in three patients who showed a low but detectable antibody level. In spite of normal or even elevated serum IgG and IgM levels there was a significantly lower response of the IgG and IgM anti-HPH antibodies at 2 weeks after immunization as compared to the controls followed by a further decline at 6 weeks. We conclude that selective IgA deficiency is often accompanied by more general disturbances in humoral and cellular immunity to newly encountered antigens.

Adolescent↗

PubMed1982

Recovery of immune function after cessation of maintenance therapy in acute lymphoblastic leukemia (ALL) of childhood.

In previously healthy children, serum immunoglobulin levels at diagnosis of acute lymphoblastic leukemia (ALL) were entirely in the normal range. After antileukemic therapy had been given for 26-27 months, serum immunoglobulin levels were low. In 32 children these parameters could be followed for periods up to 3 years after cessation of therapy, the patients remaining in unmaintained remission. At cessation of therapy serum immunoglobulin levels were at the tenth centile of the normal range or slightly below. IgG promptly returned to normal levels and then remained in the normal range. IgA levels were restored much more slowly. Most striking was the slow and incomplete return of serum IgM to normal levels. Even after a follow-up of 3 years the mean was still subnormal. This was not accompanied by clinical signs of disturbed immunity. Our study points out that in assessing the long-term immunosuppressive effects of anticancer therapy the follow-up period must be sufficiently long.

Adolescent↗

PubMed1982

Tumor xenotransplantation in Wistar rats after treatment with cyclophosphamide and total lymphoid irradiation.

Three-month-old male Wistar rats were treated with cyclophosphamide and total lymphoid irradiation, and C22LR mouse osteosarcoma was transplanted into the rats. The effects of immunosuppression were monitored by lymphocyte counts, serum IgG determinations, phytohemagglutinin (PHA) and concanavalin A (Con A) responses, measurement of the proportion of B cells, and histopathological studies of the lymphoid organs. At eight days after treatment, the lymphocyte counts, IgG levels, and PHA and Con A values were decreased. Mitotic activity started in the depleted B and T cell areas of the peripheral lymphatic organs two weeks after treatment. There was a 94% graft take of the osteosarcoma. It was determined that the optimum time for tumor xenograft transplantation is 4 days after treatment. The duration of growth was 11 days, and this was followed by regression up to day 21.

Animals↗

PubMed1982

Low-renin, low-aldosterone hypertension and abnormal cortisol metabolism in a 19-month-old child.

A 19-month-old boy presented with failure to thrive and polydipsia. Low-renin hypertension was diagnosed by the presence of hypertension, hypokalaemic alkalosis, suppressed plasma renin activity and low plasma aldosterone. Plasma levels and urinary excretion of other mineralocorticoids and glucocorticosteroids were low or normal. Urinary tetrahydrocortisol (THF) was increased relative to tetrahydrocortisone (THE) and also the plasma cortisol to cortisone ratio was elevated. These findings are suggestive of a decreased activity of cortisol-11 beta-hydroxysteroid dehydrogenase. Hypertension and hypokalaemia were not influenced by spironolactone and dexamethasone. Triamterene normalised serum potassium, but addition of furosemide was required for lowering blood pressure. With this treatment catch-up growth was observed.

Aldosterone↗

PubMed1981

A new chromosomal instability disorder: the Nijmegen breakage syndrome.

A 10-year-old boy with microcephaly, stunted growth, mental retardation, café-au-lait spots and immunodeficiency is described. An older brother of the patient had the same clinical symptoms and a more severe immunodeficiency. Cytogenetic studies in the proband revealed a typical form of chromosome instability with multiple rearrangements of chromosomes 7 and 14. Such abnormalities were also present, though in very low frequencies, in the father and three of the phenotypically normal sibs. The similarity of the symptoms in the two sibs, the close consanguinity of their parents and the results of the cytogenetic studies in the family favour the hypothesis that the disorder is an inherited one. The clinical features and the chromosome aberrations as present in the proband are usually found in chromosomal breakage syndromes, but it was possible to exclude each of the classical chromosomal breakage syndromes on clinical and/or cytogenetic grounds.

Adolescent↗