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Showing papers by "University of Amsterdam published in 1989"




Journal ArticleDOI
TL;DR: The results of this study support the need for a long-term clinical, endoscopic, and histologic follow-up program in patients with Barrett's esophagus with an incidence of carcinoma of 1 in 52 patient-years, a 125-fold increase compared with the general Dutch population.

869 citations


Journal ArticleDOI
01 Oct 1989-Blood
TL;DR: Levels of IL-6 on admission appeared to be of prognostic significance: levels were higher in septic patients who subsequently died than in those who survived, in particular when only patients with septic shock were considered.

763 citations


Journal ArticleDOI
TL;DR: It is concluded that in infants with severe congenital hypothyroidism, substantial amounts of T4 are transferred from mother to fetus during late gestation.
Abstract: The fact that neonates who subsequently have severe hypothyroidism have no evidence of the condition at birth suggests the possibility of the placental transfer of thyroid hormones. Recent studies have demonstrated the existence of such transfer in hypothyroid rats. To determine whether there is a transfer of thyroxine (T4) from mother to fetus, we studied 25 neonates born with a complete inability to iodinate thyroid proteins and therefore to synthesize T4. This total organification defect is an autosomal recessive disorder with an incidence of approximately 1 in 60,000 neonates in the Netherlands. In the cord serum of affected neonates, T4 levels ranged from 35 to 70 nmol per liter. Since these patients were unable to produce any T4, the T4 must have originated in their mothers. The estimated biologic half-life of serum T4 was 3.6 days (95 percent confidence interval, 2.7 to 5.3). In 15 neonates with thyroid agenesis, the serum levels and the disappearance kinetics of T4 were the same as those in the neonates with a total organification defect, suggesting that in these infants, the T4 also had a maternal origin. We conclude that in infants with severe congenital hypothyroidism, substantial amounts of T4 are transferred from mother to fetus during late gestation.

694 citations


Journal ArticleDOI
TL;DR: Findings indicate that variability in the biological properties of HIV isolates is one of the factors influencing the course of HIV infection.
Abstract: Sequential human immunodeficiency virus (HIV) isolates, recovered from a panel of longitudinally collected peripheral blood mononuclear cells obtained from 20 initially asymptomatic HIV-seropositive homosexual men, were studied for differences in replication rate, syncytium-inducing capacity, and host range. Eleven individuals remained asymptomatic; nine progressed to acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC) at the time point at which the last HIV isolate was obtained. In 16 individuals, only non-syncytium-inducing (NSI) isolates, with a host range restricted to mononuclear cells, were observed. From four individuals, high-replicating, syncytium-inducing (SI) isolates that could be transmitted to the H9, RC2A, and U937 cell lines were recovered. From two of these four individuals, SI isolates were obtained throughout the observation period. In the two others, a transition from NSI to SI HIV isolates was observed during the period of study. Three of these four individuals developed ARC or AIDS 9 to 15 months after the first isolation of an SI isolate. With the exception of the two individuals in whom a transition from NSI to SI isolates was observed, within a given individual the replication rate of sequential HIV isolates was constant. A significant correlation was found between the mean replication rate of isolates obtained from an individual and the rate of CD4+ cell decrease observed in this individual. In individuals with low-replicating HIV isolates, no significant CD4+ cell loss was observed. In contrast, recovery of high-replicating isolates, in particular when these were SI isolates, was associated with rapid decline of CD4+ cell numbers and development of ARC or AIDS. These findings indicate that variability in the biological properties of HIV isolates is one of the factors influencing the course of HIV infection.

668 citations


Journal ArticleDOI
TL;DR: Zidovudine treatment in the symptom-free period seemed to delay the onset of AIDS in all risk groups, although stabilisation of CD4+ cell numbers was observed only in individuals with non-syncytium-inducing HIV variants.

610 citations


Journal ArticleDOI
TL;DR: In this article, a detailed analysis of the Lateglacial type section from Usselo has been carried out and the results show that the most probable age limits of the Earlier Dryas in the Netherlands are 12,150±100 and 11,900±50 B.P.

562 citations


Journal ArticleDOI
TL;DR: A retrospective study testing the efficacy of this classification found that patients with an activity score of 3 or more at the beginning of therapy responded well to anti-inflammatory drugs, while those with a lower activity score mostly did not.
Abstract: Patients with serious inflammatory Graves' ophthalmopathy should be treated with anti-inflammatory drugs or radiotherapy to prevent complications like fibrosis, while those with non-inflammatory ophthalmopathy may be treated by surgery immediately. It is often difficult, however, to distinguish inflammatory from non-inflammatory Graves' disease. We therefore present a simple clinical classification here to differentiate between these two conditions. This classification is based on the classical signs of inflammation--pain, redness, swelling, and impaired function. After two consecutive clinical examinations an 'activity score' can be determined, ranging from 0 to 10 points. In a retrospective study testing the efficacy of this classification we found that patients with an activity score of 3 or more at the beginning of therapy responded well to anti-inflammatory drugs, while those with a lower activity score mostly did not. Comparing the pretreatment activity score with the degree of enlargement of the extraocular muscles on the CT scan, we found a significant correlation between these two parameters: the higher the activity score, the more the enlargement of the muscles. We conclude that this classification facilitates the proper selection of patients for treatment.

539 citations


Journal ArticleDOI
TL;DR: In this paper, the authors discuss the definition, detection, and explanation of item bias, and four strategies are described: qualitative, correlational, quasi-experimental, and experimental research.

474 citations


Journal ArticleDOI
TL;DR: Experimental kinematic and kinetic data on jumping and cycling show that the temporally ordered sequence in timing of leg muscle activation patterns as well as co-activation of mono-articular hip and knee extensor muscles and their bi-Articular antagonists are in concert with these constraints.

Journal ArticleDOI
TL;DR: This paper gives the view of what a distributed system is, and describes the three main characteristics that distinguish distributed programming languages from traditional sequential languages, namely, how they deal with parallelism, communication, and partial failures.
Abstract: When distributed systems first appeared, they were programmed in traditional sequential languages, usually with the addition of a few library procedures for sending and receiving messages. As distributed applications became more commonplace and more sophisticated, this ad hoc approach became less satisfactory. Researchers all over the world began designing new programming languages specifically for implementing distributed applications. These languages and their history, their underlying principles, their design, and their use are the subject of this paper.We begin by giving our view of what a distributed system is, illustrating with examples to avoid confusion on this important and controversial point. We then describe the three main characteristics that distinguish distributed programming languages from traditional sequential languages, namely, how they deal with parallelism, communication, and partial failures. Finally, we discuss 15 representative distributed languages to give the flavor of each. These examples include languages based on message passing, rendezvous, remote procedure call, objects, and atomic transactions, as well as functional languages, logic languages, and distributed data structure languages. The paper concludes with a comprehensive bibliography listing over 200 papers on nearly 100 distributed programming languages.

Journal ArticleDOI
TL;DR: It is concluded that even low levels of cadmium in soil may endanger the functioning of some sensitive soil animal species and a three-step procedure of risk assessment for soil contaminants is proposed.

Journal ArticleDOI
TL;DR: The liposomes are ingested by the macrophages which are then destroyed following phospholipase-mediated disruption of the liposomal bilayers and release of the Cl2MDP.

Journal ArticleDOI
TL;DR: It is suggested that IL-6 produced by osteogenic cells may be a mediator in PTH-stimulated osteoclastic bone resorption and this action is exerted probably through an effect on the formation of osteoclasts (osteoclastogenesis) rather than on the activation of already existing mature osteoclabs.

Journal ArticleDOI
TL;DR: SDF is a formalism for the definition of syntax which is comparable to BNF in some respects, but has a wider scope in that it also covers the definitionof lexical and abstract syntax.
Abstract: SDF is a formalism for the definition of syntax which is comparable to BNF in some respects, but has a wider scope in that it also covers the definition of lexical and abstract syntax. Its design and implementation are tailored towards the language designer who wants to develop new languages as well as implement existing ones in a highly interactive manner. It emphasizes compactness of syntax definitions by offering (a) a standard interface between lexical and context-free syntax; (b) a standard correspondence between context-free and abstract syntax; (c) powerful disambiguation and list constructs; and (d) an efficient incremental implementation which accepts arbitrary context-free syntax definitions. SDF can be combined with a variety of programming and specification languages. In this way these obtain fully general user-definable syntax.

Journal ArticleDOI
TL;DR: It is concluded that single-drug therapy with prednisone is more effective than cyclosporine in patients with severe Graves' ophthalmopathy and the combination can be effective in patients who do not respond to either drug alone.
Abstract: It is uncertain what is the most appropriate medical therapy for patients with severe Graves' ophthalmopathy. Therefore, we carried out a single-blind, randomized clinical trial to compare the efficacy of prednisone with that of cyclosporine in 36 patients who had been euthyroid for at least two months. The two groups, each consisting of 18 patients, were similar in age, sex, and the duration and severity of ophthalmopathy. The initial dose of cyclosporine was 7.5 mg per kilogram of body weight per day, and that of prednisone was 60 mg per day, which was subsequently tapered to 20 mg per day. During the 12-week treatment period, 11 prednisone-treated and 4 cyclosporine-treated patients responded to therapy (61 percent vs. 22 percent; P = 0.018); response was manifested by decreases in eye-muscle enlargement and proptosis and improved visual acuity and total and subjective eye scores. There were no differences at base line between the patients who later responded and those who did not. Prednisone was tolerated less well than cyclosporine. After 12 weeks, patients who did not respond were treated for another 12 weeks with a combination of cyclosporine and a low dose of prednisone. Among the 9 patients who initially received prednisone, the addition of cyclosporine resulted in improvement in 5 (56 percent); among the 13 patients who received cyclosporine initially, 8 (62 percent) improved after the addition of prednisone. Combination therapy was better tolerated than prednisone treatment alone. We conclude that single-drug therapy with prednisone is more effective than cyclosporine in patients with severe Graves' ophthalmopathy. The combination can be effective in patients who do not respond to either drug alone.

Journal ArticleDOI
TL;DR: The data demonstrate the abilities of IL-1 beta and TNF-alpha to induce IL-6 production in vivo and indicate that LPS induction ofIL-6 may be mediated, at least partially, through T NF-alpha action and suggest that IL- 6 may be an important effector in the manifestation of TNF -alpha and IL- 1 beta actions in vivo.

Journal Article
TL;DR: Observations suggest that a specific in situ immune mediated hypersensitivity reaction is associated with the development of atherosclerosis.

Journal ArticleDOI
TL;DR: These experiments clearly define a second group of major dust mite allergens that demonstrate extensive structural and antigenic homology.
Abstract: Monoclonal antibody affinity chromatography was used to purify two homologous mite allergens, Der f 11 from Dermatophagoides farinae and Der p 11 from D. pteronyssinus . They have the same molecular weight (MW) (15 kd) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, they have similar amino acid compositions, and their N -terminal amino acid sequences differ in only four of the first 35 residues. An excellent correlation was observed between IgE antibody to Der f II and Der p 77 measured in sera from 65 mite-allergic patients ( r = 0.94; p Der f 11, Der f 111, and previously purified Der f 1 (MW 24 kd) was detected in 92%, 16%, and 78% of the sera by radioimmunoassay, respectively. Most patients, 41151 (80%), demonstrated IgE antibody to more than one allergen. With monoclonal antibodies fully cross-reactive with Der f 11 and Der p II, a two-site immunoassay was developed for measuring absolute quantities (nanograms or micrograms) of these allergens. In extracts rich in mite fecal material (n = 5), Der f 1 and Der p I (group I allergens) and Der f II and Der p 11 (group 11 allergens) were measured in ratios of 11:1 to 35: 1. Lower ratios (1.1:1 to 7:1) were observed in mite body extracts ( n = 6). These experiments clearly define a second group of major dust mite allergens that demonstrate extensive structural and antigenic homology.

Journal ArticleDOI
TL;DR: In this article, it was shown that there are two causes for a strong interaction between nickel species and the support: incorporation of nickel ions in the surface layers of the support during impregnation, and solid-state diffusion during calcination of the catalysts.

Journal ArticleDOI
TL;DR: In this paper, a modified fused-silica capillaries were wall modified with γ-glycidoxypropyltrimethoxysilane and polyethylene glycol 600 to decrease the influence of wall adsorption in capillary zone electrophoretic separations of proteins.

Journal ArticleDOI
TL;DR: The authors showed that the differences between first language and second language learners are due to UG principles guiding L1, but not L2 acquisition, and they also showed that alternative ways of accounting for the differences are not successful.
Abstract: There is a considerable amount of recent evidence that stable principles of Universal Grammar (UG) are available to adult second language (L2) learners in structuring their intuitions about the target language grammar. In contrast, however, there is also evidence from the acquisition of word order, agreement and negation in German that there are substantial differences between first language (L1) and L2 learners. In our view, these differences are due to UG principles guiding L1, but not L2 acquisition. We will show that alternative ways of accounting for the L1/L2 differences are not successful. Finally we will deal with the question of how our view can be reconciled with the idea that L2 learners can use UG principles to some extent in the evaluation of target sentences.

Journal ArticleDOI
TL;DR: In this article, the choice between self-employment and paid employment is analyzed empirically using a so-called endogenous switching model, which features beside the choice equation earnings, equations for self-employed individuals and employees and is estimated using a two stage structural probit method.

Journal ArticleDOI
TL;DR: Patients with acute promyelocytic leukaemia were randomised either to tranexamic acid (TA group) or to placebo for 6 days to see whether inhibition of fibrinolysis would reduce haemorrhage and transfusion requirements.

Journal ArticleDOI
TL;DR: In this paper, the distinction between good and bad planning is made, and three views of the planning process are distinguished, with their associated criteria of the quality of plans: planning as con...
Abstract: This paper concerns the distinction between ‘good’ and ‘bad’ planning. Three views of the planning process are distinguished, with their associated criteria of the quality of plans: planning as con...

Journal ArticleDOI
TL;DR: The presence of α1-antichymotrypsin, complement factors and P component, but not of common serum proteins in both the amorphous and congophilic plaques, indicates that these three proteins may have a pathogenetic role in amyloid formation.
Abstract: This study was designed to investigate the role of serum proteins, microglia, glial fibrillary acidic protein (GFAP) positive cells and dystrophic neurites in the genesis of cerebral amyloid Using A4 protein antisera, we found an amorphous non-congophilic, form of plaque, which was not seen in Bielschowsky silver staining or Bodian impregnations GFAP-positive glial cells, cells immunolabelled for some macrophage markers and dystrophic neurites were detected in congophilic plaques with crystalline amyloid, but not in the amorphous, non-congophilic plaques The presence of alpha l-antichymotrypsin, complement factors and P component, but not of common serum proteins in both the amorphous and congophilic plaques, indicates that these three proteins may have a pathogenetic role in amyloid formation Amorphous plaques may be the earlier forms of plaque and consequently, the presence of reactive cells and dystrophic neurites may be secondary phenomena

Journal ArticleDOI
TL;DR: The ready availability and extreme popularity of Western pharmaceuticals in developing countries poses important general issues for medical anthropology as mentioned in this paper, and they facilitate particular social and symbolic processes that facilitate communication about experiences that may be difficult to express.
Abstract: The ready availability and extreme popularity of Western pharmaceuticals in developing countries poses important general issues for medical anthropology. In attempting to explain why medicines are so attractive in so many different cultures, this article suggests that they facilitate particular social and symbolic processes. The key to their charm is their con-creteness; in them healing is objectified. As things, they allow therapy to be disengagedfrom its social entanglements. Medicines are commodities which pass from one context of meaning to another. As substances, they are “good to think with” in both metaphoric and metonymic senses. They enhance the perception of illness as something tangible, and they facilitate communication about experiences that may be difficult to express. In the course of their transaction, they bear with them associations to authoritative professionals and the potency and potential of other cultural contexts of which they once were a part.

Journal ArticleDOI
TL;DR: The organization and expression of the genes encoding the flavonoid-biosynthetic enzyme dihydroflavonol-4-reductase (DFR) in Petunia hybrida is described and it is postulated that the An6 locus contains the DFR structural gene.
Abstract: In this paper we describe the organization and expression of the genes encoding the flavonoid-biosynthetic enzyme dihydroflavonol-4-reductase (DFR) in Petunia hybrida. A nearly full-size DFR cDNA clone (1.5kb), isolated from a corolla-specific cDNA library was compared at the nucleotide level with the pallida gene from Antirrhinum majus and at the amino acid level with enzymes encoded by the pallida gene and the A1 gene from Zea mays. The P. hybrida and A. majus DFR genes transcribed in flowers contain 5 introns, at identical positions; the three introns of the A1 gene from Z. mays coincide with first three introns of the other two species. P. hybrida line V30 harbours three DFR genes (A, B, C) which were mapped by RFLP analysis on three different chromosomes (IV, II and VI respectively). Steady-state levels of DFR mRNA in the line V30 follow the same pattern during development as chalcone synthase (CHS) and chalcone flavanone isomerase (CHI) mRNA. Six mutants that accumulate dihydroflavonols in mature flowers were subjected to Northern blot analysis for the presence of DFR mRNA. Five of these mutants lack detectable levels of DFR mRNA. Four of these five also show drastically reduced levels of activity for the enzyme UDPG: flavonoid-3-O-glucosyltransferase (UFGT), which carries out the next step in flavonoid biosynthesis; these mutants might be considered as containing lesions in regulatory genes, controlling the expression of the structural genes in this part of the flavonoid biosynthetic pathway. Only the an6 mutant shows no detectable DFR mRNA but a wild-type level for UFGT activity. Since both an6 and DFR-A are located on chromosome IV and DFR-A is transcribed in floral tissues, it is postulated that the An6 locus contains the DFR structural gene. The an9 mutant shows a wild-type level of DFR mRNA and a wild-type UFGT activity.

Journal ArticleDOI
TL;DR: A new CD40 monoclonal antibody is produced and characterized, mAb 89, which in the presence of anti‐IgM antibodies co‐stimulates to induce B cell proliferation, and the activating properties of anti-CD40 are likely to explain its co-stimulatory effect on B cells.
Abstract: We have produced and characterized a new CD40 monoclonal antibody, mAb 89, which in the presence of anti-IgM antibodies co-stimulates to induce B cell proliferation. mAb 89 activates resting B cells as shown by an increase in cell volume and an enhanced subsequent proliferation of B cells in response to anti-IgM antibody. However, mAb 89 does not prepare B cells to respond to the growth-promoting activity of interleukin (IL) 2 or IL 4. Unlike IL 2 and IL 4, mAb 89 only weakly stimulates the proliferation of anti-IgM pre-activated B cells. Thus, the activating properties of anti-CD40 are likely to explain its co-stimulatory effect on B cells. Interestingly, the anti-CD40 mAb 89 was found to act in synergy with IL 4, but not with IL 2, in co-stimulation and restimulation assays. In this respect, anti-CD40 does not induce a significant increase of B cell surface IL 4 receptors while IL 4, but not IL 2, induces a twofold increase of the CD40 antigen expression. Thus the synergistic interaction between IL 4 and anti-CD40 may be related to the IL 4-dependent increase of CD40 antigen expression.