Albert W. Van Toorenenbergen

Pharmacokinetics of intravenous immunoglobulin and outcome in Guillain-Barré syndrome.

Intravenous immunoglobulin (IVIg) is the first choice treatment for Guillain‐Barré syndrome (GBS). All patients initially receive the same arbitrary dose of 2g per kg body weight. Not all patients, however, show a good recovery after this standard dose. IVIg clearance may depend on disease severity and vary between individuals, implying that this dose is suboptimal for some patients. In this study, we determined whether the pharmacokinetics of IVIg is related to outcome in GBS.

The role of topical negative pressure in wound repair: Expression of biochemical markers in wound fluid during wound healing

The clinical effects of topical negative pressure therapy (TNP) on wound healing are well described in numerous articles. While the mechanism(s) of action are not completely understood, it is postulated that reduction of local and interstitial tissue edema, increased perfusion of the (peri‐) wound area, changed bacterial composition, and mechanical stimulation of the woundbed contribute to the clinical success. Our hypothesis is that with the removal of excessive fluid, proteolytic enzymes negatively influencing the healing process are removed. Our aim was to assess whether the concentrations of albumin, matrixmetalloproteinase‐9 (MMP‐9), and tissue inhibitor of metalloproteinase (TIMP‐1) were different between wounds treated with TNP and conventional gauze therapy. We analyzed wound fluid samples of 33 wounds treated with either TNP therapy (n=15) or conventional therapy (n=18) on albumin, pro‐ and activated MMP‐9, TIMP‐1, and the ratio of total MMP‐9/TIMP‐1. Albumin levels were found to increase significantly in acute wounds compared with chronic wounds; however, no difference could be found on comparing TNP with conventional therapy. We did find significantly lower levels of pro‐MMP‐9 and lower total MMP‐9/TIMP‐1 ratio in TNP‐treated wounds during the follow‐up of 10 days. These data strongly suggest that TNP therapy influences the microenvironment of the wound.

Prevalence of sensitization to the predatory mite Amblyseius cucumeris as a new occupational allergen in horticulture

Background: Protection against thrips, a common pest in bell pepper horticulture is effectively possible without pesticides by using the commercially available predatory mite Amblyzeius cucumeris (Ac). The prevalence of sensitization to Ac among exposed greenhouse employees and its clinical relevance was studied.

Prevalence of natural rubber latex allergy (Type I and Type IV) in laboratory workers in The Netherlands

The objective of the study was to study the prevalence of Type IV and Type I allergy to natural rubber latex (NRL) in a population at risk in the Netherlands. Laboratory workers regularly using gloves were invited to complete a questionnaire and to be tested. We performed patch tests with standard contact allergens, rubber additives, glove powder and pieces of 4 gloves; prick tests with inhalant allergens, glove extracts, glove powder and fruit extracts; and RASTs. Glove‐related hand dermatitis was reported in 36.9% of the individuals interviewed. A positive patch test result for rubber additives was seen in only 6.6%. Glove‐related urticaria, rhinoconjunctivitis and/or asthma were reported in 24.6% of all cases. Confirmation of an IgE‐mediated reaction was achieved in 8.3% by prick test with glove extracts and 5.0% by RAST No reaction to glove powder was noticed in patch testing or in prick testing. A high prevalence rate of glove‐related symptoms and NRL Type I allergy was found in laboratory workers exposed to rubber gloves. Surprisingly, there was no co‐existence of Type I and Type IV allergy in this population.

Value of urinary N-methylhistamine measurements in childhood mastocytosis

BACKGROUND Histamine is an indicator of mast cell activation. N-methylhistamine (NMH) is a metabolite of histamine that can be measured in urine. OBJECTIVE Our purpose was to assess the usefulness of determining urinary NMH levels for the diagnosis and follow-up of patients with mastocytosis. METHODS Urinary NMH levels were determined in 44 patients and were correlated with disease activity and extension. The control group consisted of 24 children without mastocytosis or any other skin disease. RESULTS A significant negative correlation was found between NMH and age in patients with active mastocytosis and in the control group. Adjusted for age, NMH values were significantly higher in patients with active mastocytosis. There was a significant difference in NMH values between patients with diffuse cutaneous mastocytosis, patients with active urticaria pigmentosa, and patients with active mastocytomas. However, there was a substantial overlap of NMH values in the different subgroups. CONCLUSION Urinary NMH values tend to decrease with age. Urinary NMH values correlated with the extent and the activity of the disease. High NMH values suggest more extensive involvement.

Plasma matrix metalloproteinase-9 levels and blood pressure in short children born small for gestational age and effects of growth hormone treatment

Context  Short small‐for‐gestational‐age (SGA) children have an increased systolic blood pressure (BP) that decreases during long‐term GH treatment. The underlying mechanism is still unknown. Matrix metalloproteinases (MMPs) are zinc‐dependent endoproteinases that are involved in the remodelling of the extracellular matrix (ECM) and are thought to play a role in atherosclerosis. High MMP‐9 levels are found in hypertensive patients and predict cardiovascular mortality.

Selective effect of levocabastine on histamine receptor and histamine release from human leukocytes and guinea pig isolated tissue

BACKGROUND Levocabastine is a potent histamine H1 receptor antagonist used topically in the treatment of patients with allergic rhinitis. It has been suggested that antihistamines also have anti-inflammatory properties. OBJECTIVE The present study was performed to investigate whether levocabastine, in addition to the anti-H1 receptor activity, has anti-inflammatory properties and thus is able to modulate the release of histamine and cytokines, such as interleukin 5 from human leukocytes and isolated tissues. METHODS Leukocytes suspensions were prepared by dextran sedimentation of peripheral venous blood drawn from allergic and healthy volunteers. Leukocytes obtained from allergic volunteers were preincubated for 30 minutes with levocabastine (doses 10(-8) M to 10(-6) M) and thereafter incubated with allergen. Leukocytes obtained from healthy volunteers were incubated for zero to three hours with levocabastine (doses 10(-14) M to 10(-3) M). Histamine release was measured by an automated fluorometric method. Interleukin-5 release was measured by enzyme linked immunoassay. Contractile responses to histamine on guinea pig trachea and lung parenchyma as well as the release of histamine and interleukin-5 by the tissues were investigated in the absence or presence of levocabastine and/or the histamine H2 receptor antagonist cimetidine. RESULTS Levocabastine did not influence allergen-induced histamine release from leukocytes obtained from allergic volunteers. High concentrations (10(-4)and 10(-3) M) of levocabastine, however, caused release of histamine from leukocytes obtained from healthy volunteers as well as guinea pig airway smooth muscle tissues. Pretreatment with levocabastine dose-dependently decreased the contractile response to histamine, showing an irreversible competitive mechanism. Interleukin 5 release from human leukocytes and by guinea pig airway smooth muscle was not detectable. CONCLUSIONS These findings indicate that the H1 receptor blocker, levocabastine, has probably no anti-inflammatory properties, measured as histamine release, and that the histamine release from both human leukocytes and guinea pig trachea and lung parenchyma is significantly increased by the drug only at high concentrations.

Long‐term GH treatment is not associated with disadvantageous changes of inflammatory markers and adipocytokines in children born small for gestational age

Context  Low birth weight is associated with increased risks for adult cardiovascular disease (CVD) and diabetes mellitus type 2 (DM2). Adiponectin and resistin are hormones, considered, respectively, protective and disadvantageous regarding these risks. No data exist on the effect of long‐term GH treatment on these hormones and inflammatory markers in children born small for gestational age (SGA).

Immunoblot and radioallergosorbent test inhibition studies of allergenic cross-reactivity of the predatory mite Amblyseius cucumeris with the house dust mite Dermatophagoides pteronyssinus

BACKGROUND In 1999, an extensive study among bell pepper growers showed that a predatory mite, Amblyseius cucumeris, is a potentially relevant source of occupational allergens because 23% of the population had positive skin prick test reactions. OBJECTIVE To investigate whether cross-reactivity between A. cucumeris and Dermatophagoides pteronyssinus is responsible for the cosensitization to both mite species found in 58.7% of A. cucumeris-sensitized greenhouse workers. METHODS Fifteen serum samples from greenhouse workers with work-related inhalant allergy and a positive radioallergosorbent test (RAST) reaction to A. cucumeris or D. pteronyssinus were selected for immunoblot analysis using extracts of both mites. A subselection (n = 5) was used for RAST and immunoblot inhibition to investigate potential cross-reactivity. RESULTS On immunoblot, 2 distinct patterns were observed: one pattern showed common protein bands in A. cucumeris and D. pteronyssinus blots suggestive of cross-reactivity between A. cucumeris and D. pteronyssinus and the other pattern showed no shared protein bands. Dermatophagoides pteronyssinus RAST inhibition with A. cucumeris extract was low in 4 serum samples (<25% inhibition) and nearly absent in 1 serum sample; A. cucumeris RAST inhibition with D. pteronyssinus extract was high in 1 serum sample (75% inhibition), low in 2 serum samples (35% and <15% inhibition), and absent in 2 serum samples. These results were confirmed by immunoblot inhibition experiments. CONCLUSIONS Amblyseius cucumeris, a new occupational allergen, has species-specific antigens and common antigens that are cross-reactive with the house dust mite D. pteronyssinus.

IgE-Mediated Hypersensitivity: Patients with Complex Regional Pain Syndrome Type 1 (CRPS1) vs the Dutch Population. A Retrospective Study

OBJECTIVE To investigate whether hypersensitivity is more common in Complex Regional Pain Syndrome type 1 (CRPS1) patients than in the general population. In a recent study, the level of tryptase, a specific marker for mast cells, was significantly higher in blister fluid from the involved extremity of CRPS1 patients. This suggested that mast cells may play a role in the pathophysiology of CRPS1. Mast cells are major effectors in allergic reactions, and are also involved in a variety of noninfectious inflammatory diseases. Patients. Sixty-six Dutch patients with CRPS1 in one extremity were included. OUTCOME MEASURES Allergy information was obtained from the medical history and a modified questionnaire based on the Europees Luchtweg Onderzoek Nederland 1 study. Total IgE and allergen-specific IgE were measured from blood samples. Also tryptase, as a marker for mast cells, was measured. The data from the questionnaire were compared with that of the general Dutch population, and the plasma levels were compared with reference values and data in the literature. RESULTS The medical history did not differ from information provided in the questionnaire by the CRPS1 group. There was no significant difference between the answers to the questionnaire between the CRPS1 patients and the general population. The total IgE levels were elevated in 30% of the CRPS1 patients compared with 15-24% of the general population, and allergen-specific IgE and tryptase levels were comparable with the reference values. CONCLUSIONS Based on the medical history, an allergy questionnaire, and objective laboratory findings we conclude that IgE-mediated hypersensitivity is not more common in CRPS1 patients than in the general population.