Biomedical subjects
Publications and source records attributed to J Boer.
A qualitative cellular solid-phase binding assay for screening alpha 4 beta 7 integrin antagonists attached via photolinker to TentaGel Macrobeads has been developed. An activation of the integrins with Mn(2+) was necessary to achieve binding to the bead bound antagonists. The identification of the resin bound compounds was done by mass spectrometry.
Interactions of the integrins alpha(4)beta(7) with its cognate ligand mucosal addressin cell adhesion molecule-1 (MAdCAM-1) play a crucial role in the development of mucosa-associated lymphoid organs, in the generation of mucosal immune responses, and in diverse pathological processes such as chronic inflammatory bowel disease and type I diabetes. Using a previously developed spatial screening technique we describe the development of potent and selective alpha(4)beta(7) integrin antagonists based on the domain 1 Leu-Asp-Thr (LDT) sequence of MAdCAM-1 that is essential for alpha(4)beta(7) integrin binding. A library of homodetic cyclic penta- and hexapeptides was synthesized presenting the pharmacophoric LDT-sequence in different conformations. The cyclic hexapeptide P10 cyclo(Leu-Asp-Thr-Ala-D-Pro-Ala) inhibits alpha(4)beta(7) integrin mediated cell adhesion to MAdCAM-1 effectively. Further optimization of the lead structure P10 resulted in cyclic hexapeptides with enhanced activity. The compounds P25 cyclo(Leu-Asp-Thr-Ala-D-Pro-Phe), P28 cyclo(Leu-Asp-Thr-Asp-D-Pro-Phe), P29 cyclo(Leu-Asp-Thr-Asp-D-Pro-His), and P30 cyclo(Leu-Asp-Thr-Asp-D-Pro-Tyr) strongly inhibited alpha(4)beta(7) integrin mediated cell adhesion to MAdCAM-1, but they did not affect binding of the closely related alpha(4)beta(1) integrin to VCAM-1.
MOTIVATION: The technology of hybridization to DNA arrays is used to obtain the expression levels of many different genes simultaneously. It enables searching for genes that are expressed specifically under certain conditions. However, the technology produces large amounts of data demanding computational methods for their analysis. It is necessary to find ways to compare data from different experiments and to consider the quality and reproducibility of the data. RESULTS: Data analyzed in this paper have been generated by hybridization of radioactively labeled targets to DNA arrays spotted on nylon membranes. We introduce methods to compare the intensity values of several hybridization experiments. This is essential to find differentially expressed genes or to do pattern analysis. We also discuss possibilities for quality control of the acquired data. AVAILABILITY: http://www.dkfz.de/tbi CONTACT: M.Vingron@dkfz-heidelberg.de
BACKGROUND: Oral isotretinoin has been used to treat mild to severe hidradenitis suppurativa (HS). OBJECTIVE: We reviewed the results of low-dose isotretinoin for 4 to 6 months in the treatment of 68 patients with HS. METHODS: This is a retrospective study. Data are presented in terms of response rate, long-term follow-up, and the relation between response rate and severity. RESULTS: In 16 patients (23.5%), the condition completely cleared during initial therapy and 11 patients (16.2%) maintained their improvement during the follow-up period. Treatment was more successful in the milder forms of HS. CONCLUSION: Monotherapy with isotretinoin for patients with HS usually has a limited therapeutic effect.
1. Using a guinea-pig model of allergic asthma, we investigated the role of L-arginine limitation in the allergen-induced deficiency of nitric oxide (NO) and airway hyperreactivity (AHR) after the early asthmatic reaction, by examining the effects of various concentrations of the NO synthase (NOS) substrate on the responsiveness to methacholine of isolated perfused tracheae from unchallenged (control) animals and from animals 6 h after ovalbumin challenge. 2. Preparations from ovalbumin-challenged guinea-pigs showed a 1.9 fold increase in the maximal response (Emax) to intraluminal (IL) administration of methacholine compared to controls (P<0.001). A similar 2.0 fold (P<0.05) increase in Emax to methacholine was observed in control airways incubated with the NOS inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME; 0.1 mM, IL), while L-NAME had no further effect on the airways from ovalbumin-challenged animals. 3. In control airways, extraluminal (EL) administration of 0.3, 1.0 and 5.0 mM L-arginine all suppressed the Emax for methacholine by approximately 40% (P<0.01 all), whereas 5.0 mM D-arginine (EL) had no effect. 4. L-Arginine dose-dependently reduced the AHR to methacholine in tracheae from ovalbumin-challenged guinea-pigs, the responsiveness being normalized in the presence of 5.0 mM L-arginine. As in controls, 5.0 mM D-arginine was without effect. 5. The results demonstrate that deficiency of endogenous NO contributes to the allergen-induced AHR to methacholine after the early asthmatic reaction, which is reversed by exogenous administration of L-arginine. This indicates that limitation of substrate may underly the reduced cNOS activity and subsequent AHR after the acute asthmatic response.
Explore the source record for details and available documents.
The human CAN gene was first identified as a target of t(6;9)(p23;q34), associated with acute myeloid leukemia and myelodysplastic syndrome, which results in the expression of a DEK-CAN fusion gene. CAN, also called NUP214, is a nuclear pore complex (NPC) protein that contains multiple FG-peptide sequence motifs. It interacts at the NPC with at least two other proteins, the nucleoporin NUP88 and hCRM1 (exportin 1), which was recently shown to function as a nuclear export receptor. Depletion of CAN in knockout mouse embryonic cells results in cell cycle arrest in G2, followed by inhibition of nuclear protein import and a block of mRNA export. We overexpressed CAN and DEK-CAN in U937 myeloid precursor cells. DEK-CAN expression did not interfere with terminal myeloid differentiation of U937 cells, whereas CAN-overexpressing cells arrested in G0, accumulated mRNA in their nuclei, and died in an apoptotic manner. Interestingly, we found that hCRM1 and import factor p97/importin beta colocalized with the ectopically expressed CAN protein, resulting in depletion of both factors from the NPC. Overexpression of the C-terminal FG-repeat region of CAN, which contains the binding site for hCRM1, caused sequestering of hCRM1 in the nucleoplasm and was sufficient to inhibit cell growth and to induce apoptosis. These results confirm that CAN plays a crucial role in nucleocytoplasmic transport and imply an essential role for hCRM1 in cell growth and survival.
BACKGROUND: Variations at the DNA level with moderate effects on biochemical variables may be important for the occurrence of disease at the population level, if they are common. Two mutations in the LPL gene, N9 and S291, are associated with variation in fasting plasma concentrations of HDL cholesterol (HDL-C) and triglycerides (TG). We investigated whether these mutants were more frequent in offspring of cases with premature coronary disease and analyzed the effects on fasting plasma lipids and postprandial TG. METHODS AND RESULTS: Students with and without paternal history of myocardial infarction (cases and control subjects [controls]) were studied in the European Atherosclerosis Research Studies I and II (EARS-I and -II). Allelic frequencies for the N9 and S291 mutations did not differ between cases and control subjects. The N9 mutation was identified in 4.2% of all subjects in EARS-I, and carriers had higher fasting TG levels (P<.001) than noncarriers. In an oral fat tolerance test, there were no differences in postprandial TG between carriers and noncarriers of the N9 allele. The S291 mutation was identified in 3.1% of all subjects in EARS-I, and carriers had lower fasting HDL-C levels (P<.005) than noncarriers. There was a significant interaction between S291 genotype and body mass index on fasting TG levels (P<.01). In the cases, carriers of the S291 allele had higher TG levels 6 hours postprandially (P<.04) than did noncarriers. CONCLUSIONS: The two LPL mutations are common and may predispose to elevated TG and decreased HDL-C concentrations, even in young subjects. In the case of the S291 mutation, this effect appears to be mediated via delayed postprandial TG clearance. Moreover, even moderate obesity potentiates the TG-raising and HDL-lowering effects associated with the S291 allele.
Explore the source record for details and available documents.
The recurrent chromosomal translocation (6;9) is associated with acute myeloid leukemia and results in expression of the DEK-CAN fusion protein. This oncoprotein consists of almost the entire DEK protein fused to the C-terminal two-thirds of the CAN protein. In much the same way, CAN is fused to SET in a patient with acute undifferentiated leukemia, producing a SET-CAN fusion protein. Interestingly, CAN is associated with the nuclear pore complex (NPC) and we recently established its crucial role in nucleocytoplasmic transport processes and cell cycle progression. As a first step in the biochemical analysis of the oncogenic mechanism associated with translocation (6;9), we set out to identify proteins that interact with CAN and its fusion proteins. We found that two proteins specifically co-immunoprecipitate with CAN. One had a molecular mass of 88 kDa protein (CC88) and was determined to associate with the central region of CAN that contains several protein interaction motifs. A second protein of 112 kDa (CC112) was found to interact with the C-terminal nucleoporin-specific repeat of CAN, a region that is supposed to function in nucleocytoplasmic transport. CC112 also interacts with the DEK-CAN and SET-CAN fusion proteins. This finding suggests that CC112 may contribute an essential function to the leukemogenic effect of DEK-CAN and SET-CAN.
The vertebrate nucleopore complex (NPC) is a 125 MDa multiprotein assembly that mediates nucleocytoplasmic transport. One of its components, CAN/Nup214, is an FXFG repeat-containing protein known to be involved in myeloid leukemia in humans. We have devised a powerful genetic approach, using maternally derived protein in murine null embryos, to show that CAN/ Nup214 is essential for NPC function in vivo. We demonstrate that CAN-/- mouse embryonic stem (ES) cells are not viable and that CAN-/- embryos die in utero between 4.0 and 4.5 days postcoitum, following the depletion of their CAN from maternal sources. In 3.5-day-old mutant embryos, cultured in vitro, progressive depletion of CAN leads to cell cycle arrest in G2 phase, and eventually to blastocoel collapse, impaired NLS-mediated protein uptake and nuclear accumulation of polyadenylated RNA. Remarkably, these defective CAN-depleted embryos do not display any gross morphological abnormalities in their nuclear envelopes or NPCs. Our data suggest that CAN is critical to cell cycle progression and required for both nuclear protein import and mRNA export.
The pathogenesis of hidradenitis suppurativa (HS) has given rise to controversy about whether the central pathogenetic feature is an apocrine follicular occlusion (with subsequent bacterial infection) or it is a folliculitis with secondary involvement of both apocrine and eccrine sweat glands. Most previous concepts have focused on apocrine gland involvement. A prospective study of 27 consecutive patients (39 biopsies) was performed to investigate the immune-histological findings in early, newly formed lesions. Most of them were examined within 3 days of clinical onset. Histopathological findings showed that the initial lesion is an occluding spongiform infundibulo-folliculitis. Furthermore, it was found that T cells predominated in the lymphocytic cell population. A high percentage of HLA-DR positive lymphocytes was found in an inverse relationship with Leu-8 positive lymphocytes. Additionally, a sharp decline in the T-helper/suppressor ratio was observed after the initiation. These results reveal that the primary event in HS is an infundibulofolliculitis with secondary involvement of apocrine glands. Acne inversa would be a more appropriate name.
Fusion genes encoding the 3' part of the can gene are implicated in two types of leukemia. The dek-can fusion gene is present in t(6;9) acute myeloid leukemia and the set-can fusion gene is present in one case of acute undifferentiated leukemia. In order to obtain leads towards the molecular basis of these diseases, we have studied the cellular localization of the DEK-CAN and SET-CAN fusion proteins and their normal counterparts. DEK-CAN and SET-CAN were localized exclusively in the nucleus, and also DEK and SET were found to be nuclear proteins. However, CAN was mainly located at the nuclear and cytoplasmic face of the nuclear envelope. This observation is in accordance with the presence of an amino acid repeat in the C-terminal part of CAN, common to the family of nucleoporins. The C-terminal part also contains a nuclear location domain as shown by deletion analysis. This domain may be important for the presence of CAN at the nucleoplasmic side of the nuclear envelope. The relocation of the carboxyterminal part of CAN due to DEK-CAN and SET-CAN may reinforce a nuclear function of the CAN protein.
This study was aimed at investigating the effect of exercise on energy balance under dietary conditions differing by the relative lipid content of foods. Nine healthy men performed a 60-min treadmill exercise followed by a 48-h observation period during which they maintained their habitual daily activities and had free access to either a low-fat, a mixed, or a high-fat diet. Energy balance, summing up the excess of energy expended during exercise and the 48-h postexercise energy balance, was -6.4, -4.5, and 0.9 MJ under low-fat, mixed, and high-fat diet conditions, respectively. These observations suggest that exercise can induce a substantial energy deficit when a low-fat diet conforming to nutritional recommendations is consumed after exercise. They also suggest that the increase in energy intake associated with a high-fat diet is sufficient to fully compensate for the energy deficit resulting from the energy cost of exercise and the increase in postexercise energy expenditure.
In 8 female sports students (runners) aged 20 and 21 years and 10 women between 20 and 40 years of age, who regularly underwent body building training, serum levels of ethinylestradiol (EE2) and levonorgestrel (LNG) have been determined under conditions of exercise as well as in rest, prior to and following the intake of 1 tablet of Gravistat (0.05 mg EE2, 0.125 mg LNG). Blood samples were obtained at points 0, 2, 6 and 24 hours. Exercise (5000 meter running and intensive body building training of one hour duration, respectively) was started immediately after intake of the steroid combination. There were no significant differences in the serum concentration levels obtained during exercise and rest. But exercise consistently resulted in a slight decrease of EE2 and LNG serum concentrations and the area under curve values.
Pharmacokinetic investigations (c0h, c2h, c6h, c24h, AUC24) were carried out both in the first and last four days of a treatment cycle in patients of different ages, who used oral contraceptives at least for 12 months. 57 women took the preparation Trisiston (three-step-formulation with the components 0.03 mg ethinylestradiol (EE2) + 0.05 mg levonorgestrel (LNG), 0.04 mg EE2 + 0.075 mg LNG, 0.03 mg EE2 + 0.125 mg LNG), 23 subjects used Gravistat (0.05 mg EE2 + 0.125 mg LNG) and 17 patients were under Certostat, a preparation still in clinical evaluation (0.05 mg EE2 + 2.0 mg Dienogest (DNG)). The levels of EE2, LNG and DNG were measured by means of radioimmunoassays. Between the concentrations obtained after administration of a first and single tablet (earlier investigations) and those determined in long-time users during the first 4 days following the tablet-free interval no qualitative and quantitative differences were observed. Between the levels of EE2 and LNG determined in the first and last days of the treatment cycle, marked differences were found in patients under the formulations Trisiston and Gravistat, but not in those taking Certostat. It is concluded that a cyclic and reversible cumulating effect emerges under the influence of LNG-containing contraceptives, the mechanism of which cannot be explained solely by the increase of carrier protein capacity. It seems possibly due to an alteration of steroid metabolism resulting from the interaction between both components.
The administration of UVB phototherapy and low-dose acitretin (0.34-0.44 mg/kg body weight) was compared with the effect of acitretin alone and UVB phototherapy alone in 41 patients with plaque-type psoriasis. Of these patients, 32 received standard UVB phototherapy without acitretin. The other nine were treated with acitretin and the effect of UVB irradiation (Sylvania UV 21-tubes), applied to one half of the body, was assessed. Clearance was defined as 80-100% improvement and this occurred in eight out of the nine patients (89%) treated with acitretin-UVB (ReUVB) and, in two of them (23%), on the untreated side. Clearance occurred in 20 of the 32 (62.5%) patients given UVB alone. The improvement score was significantly higher for the ReUVB side than the acitretin side. Patients treated with ReUVB showed a statistically higher therapeutic score (95-100% clearance) than those receiving UVB alone. However, taking 80-100% improvement as the criterion, no significant difference was found. The number of treatments to clearance was significantly less for the patients treated with ReUVB than for the UVB (19.3 as compared with 24.9). The total UVB dose and the number of minimal erythema doses (MEDs) could be reduced by approximately 20% in the ReUVB group relative to the UVB group.
Jessner's lymphocytic infiltration of the skin is a well-known but poorly understood disorder. Some doubt still exists about whether it is a single entity or a heterogeneous group that can pass into polymorphous light eruption, discoid lupus erythematosus, or even malignant lymphoma. Therefore, a large number of patients with lymphocytic infiltration of the skin (N = 100; 46 male, 54 female) were examined to elucidate these questions. We conclude that lymphocytic infiltration of the skin is a single entity. Progression into polymorphous light eruption, discoid lupus erythematosus, or lymphoma was not observed. However, this study shows that lymphocytic infiltration of the skin and polymorphous light eruption cases occur simultaneously in 1 patient. In this study the cases of 10 patients with this combination are reported. An effective but harmless therapy is yet unknown. Intermittent use of topical steroids can be useful but is not effective in many patients.