'Root-food' and the rhizosphere microbial community composition.
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Bacteria↗
Biomedical subjects
W de Boer
Publications and source records attributed to W de Boer.
EGRET excess of diffuse galactic gamma rays interpreted as a signal of dark matter annihilation.
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Comment↗
Management issues in dyspepsia: current consensus and controversies.
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Breath Tests↗
Psychological distress in chronic craniomandibular and cervical spinal pain patients.
Recent studies to chronic pain have shown that the number of painful body areas is related to the level of psychological distress. Therefore, the first aim of this study was to analyse differences in level of psychological distress between craniomandibular pain patients with or without cervical spinal pain. In this analysis, the number of painful body areas below the cervical spine was also taken into account. The second aim was to determine psychological differences between subgroups of craniomandibular pain patients. In this study, 103 out of 250 persons with or without craniomandibular pain were included in the final analyses. Patients who suffered from both craniomandibular and cervical spinal pain showed higher levels of psychological distress, as measured with the Symptom Checklist 90 (SCL-90) than patients with local craniomandibular pain and persons without pain. Further, a positive relationship was found between the number of painful body areas below the cervical spine, as measured on a body drawing, and the SCL-90 scores. No psychological differences were found between myogenous and arthrogenous craniomandibular pain patients. In conclusion, chronic craniomandibular pain patients with a coexistent cervical spinal pain showed more psychological distress compared to patients with only a local craniomandibular pain and asymptomatic persons.
Adult↗
Prevalence of cervical spinal pain in craniomandibular pain patients.
It has often been suggested that patients with a craniomandibular disorder (CMD) more often suffer from a cervical spine disorder (CSD) than persons without a CMD. However, in most studies no controlled, blind design was used, and conclusions were based on differing signs and symptoms. In this study, the recognition of CMD and CSD was based upon the presence of pain. The aim of this study was to determine the prevalence of cervical spinal pain in persons with or without craniomandibular pain, using a controlled, single-blind design. From 250 persons, a standardised oral history was taken, and a physical examination of the masticatory system and the neck was performed. Three classification models were used: one based on symptoms only; a second on signs only; and a third one based on a combination of symptoms and signs. The CMD patients were also subdivided in three subgroups: patients with mainly myogenous pain; mainly arthrogenous pain; and both myogenous and arthrogenous pain. Craniomandibular pain patients more often showed cervical spinal pain than persons without craniomandibular pain, independent of the classification model used. No difference in the prevalence of cervical spinal pain was found between the three subgroups of craniomandibular pain patients.
Adult↗
Assessment of Helicobacter pylori vacA and cagA genotypes and host serological response.
Helicobacter pylori strains can be distinguished by genotyping of virulence-associated genes, such as vacA and cagA. Because serological discrimination between strain types would reduce the need for endoscopy, 61 patients carrying H. pylori were studied by vacA and cagA genotyping of H. pylori in gastric biopsy specimens and by detection of specific serum antibodies. Serological responses to H. pylori were determined by Helicoblot (versions 2.0 and 2.1). Antibodies to CagA also were determined by a rapid anti-CagA assay (Pyloriset screen CagA) as well as by two noncommercially developed enzyme immunoassays, each using a recombinant CagA protein. Assessment of performance of the Helicoblot assays indicated substantial interobserver variation, with kappa values between 0.20 and 0.93. There was no relationship between the serological profiles on the Helicoblot and the genotypes from the same patients, except for strong associations between the presence of anti-CagA and the cagA-positive and vacA s1 H. pylori genotypes. Detection of anti-CagA by the five different assays varied considerably, with kappa values ranging from 0.21 to 0.78. Using the cagA genotype as the "gold standard," the sensitivity and specificity of the anti-CagA assays varied from 71.4 to 85.7% and from 54.2 to 100%, respectively. Thus, serological profiles of antibodies to H. pylori are heterogeneous and, with the exception of anti-CagA antibodies, show no relation to the H. pylori vacA and cagA genotypes. Detection of anti-CagA antibodies is strongly dependent on the test used.
Antibodies, Bacterial↗
Degradation of ethinyl estradiol by nitrifying activated sludge.
Degradation of ethinyl estradiol (EE2) by nitrifying activated sludge was studied with micro-organisms grown in a reactor with feedback of sludge fed with only a mineral salts medium containing ammonium as the sole energy source. Ammonium was oxidised by this sludge at a rate of 50 mg NH4+ g(-1) DW h(-1). This activated sludge was also capable of degrading EE2 at a maximum rate of 1 microg g(-1) DW h(-1). Using sludge with an insignificant nitrifying capacity of 1 mg NH4+ g(-1) DW h(-1), no degradation of EE2 was detected. Oxidation of EE2 by nitrifying sludge resulted in the formation of hydrophilic compounds, which were not further identified. Most probably degradation by nitrifying sludge results in a loss of estrogenic activity, as hydroxylated derivatives of EE2 are known to have a substantially lower pharmacological activity than EE2.
Estradiol Congeners↗
Clinical tests in distinguishing between persons with or without craniomandibular or cervical spinal pain complaints.
The recognition of a craniomandibular or cervical spinal pain is usually based upon the pain complaint of the patient, reported during an oral history, and the pain responses provoked in a clinical examination. Often used clinical tests are palpation, and function tests like dynamic/static tests or active movements. The relative importance of these tests for the recognition of the musculoskeletal pain is important. Therefore, it was the aim of the present study to determine which test, or combination of tests, best discriminates between persons with or without craniomandibular and/or cervical spinal pain complaints. Two hundred and fifty persons participated. From each person, a standardized oral history was taken. Then, in a randomized order and using a blind design, physical examinations of the craniomandibular system and of the neck were performed. Forward stepwise logistic regression analyses showed that the dynamic/static tests discriminated better between persons with and without pain complaints than the other tests did. In conclusion, in studies to the coexistence of craniomandibular and cervical spinal pain, it may be a good choice to base the recognition of these disorders on the pain complaints reported in the oral history which are verified by the pain response of the dynamic/static tests.
Adult↗
Clinical relevance of the cagA, vacA, and iceA status of Helicobacter pylori.
BACKGROUND & AIMS: Clinical outcome of Helicobacter pylori infection may be associated with specific virulence-associated bacterial genotypes. The aim of this study was to assess the relationships between H. pylori cagA, vacA, and iceA status and severity of disease. METHODS: Gastric biopsy specimens from 94 patients in The Netherlands were analyzed by polymerase chain reaction and reverse hybridization. RESULTS: cagA was present in 63 (67%) of 94 cases and was associated with peptic ulcer disease (P = 0.0019). vacA geno-types s1a/m1, s1b/m2, s1b/m1, s1b/m2, and s2/m2 were found in 36.2%, 23.4%, 2.1%, 5.3%, and 20.2%, respectively. Ten isolates (10.6%) contained multiple vacA genotypes. The presence of peptic ulcers was associated with type s1 strains (P = 0.0006) but not with the m type (P = 0.2035). cagA and vacA s1 were strongly associated (P < 10(-5)). iceA1 was found in 53 (56.4%) and iceA2 in 25 (26.6%) of the 94 cases. In 14 isolates (14.9%), both iceA alleles were found, and 2 (2.1%) were negative for both iceA1 and iceA2. iceA1 was also associated with peptic ulcer disease (P = 0.0042). The iceA allelic type was independent of the cagA and vacA status. CONCLUSIONS: vacA s1, cagA, and iceA1 are markers of H. pylori strains that are more likely to lead to ulcer disease.
Adult↗
Molecular biology and biochemistry of human recombinant follicle stimulating hormone (Puregon).
Follicle stimulating hormone (FSH) is a heterodimeric glycoprotein hormone produced in the anterior pituitary gland. The hormone is essential in the regulation of reproductive processes, such as follicular development and ovulation. It is clinically used for treatment of anovulation and in assisted reproduction technologies such as in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). Until recently, the only source for human FSH has been the urine from post-menopausal women. Such a natural source implies limited availability and potential product variability. Thus, we have cloned the genes encoding the alpha- and beta-subunits of human FSH and transfected these into Chinese hamster ovary (CHO) cells. A CHO-clone was isolated capable of secreting intact glycosylated FSH with identical amino acid sequences to natural FSH. This cell line was grown in perfusion culture and enabled us to isolate highly pure FSH (> 99%). The complexity of the charge distribution of human recombinant FSH was demonstrated by Isoelectric focusing. The observed microheterogeneity is caused by the large number of carbohydrate chain structures which are added to the four potential glycosylation sites in the alpha beta-dimer. Furthermore, the carbohydrates show a variation in their degree of sialylation which reflects the different pl values of the individual isohormones. Despite the complexity of post-translational modification, the isoform distribution of recombinant FSH produced in a CHO-cell line and grown in perfusion culture is surprisingly similar to that observed with pituitary FSH and urinary FSH. In conclusion, we have shown that FSH-gene transfected CHO-cells are capable of stable serum-free production of recombinant FSH. A process has been developed which assures the consistent and reproducible production of highly-purified recombinant FSH.
Animals↗
Comparative analysis of gene sequences encoding ammonia monooxygenase of Nitrosospira sp. AHB1 and Nitrosolobus multiformis C-71.
DNA encoding ammonia monooxygenase from two phylogenetically related autotrophic nitrifying bacteria, Nitrosospira sp. AHB1 and Nitrosolobus multiformis C-71, was amplified by PCR. The resulting products were cloned into the vector pCR-Script. A continuous region of DNA of about 1.5 kb for strain AHB1 and 1.24 kb for N. multiformis C-71 was analysed. These comprised the major part of the gene amoA encoding the active site polypeptide and, directly downstream, the 5' portion of the amoB gene. The identity values for these sequences at the amino acid level were 93.0% for amoA and 96.1% for amoB. The corresponding values for the nucleic acid sequences were 86.7% and 88.8%, respectively. The identity of the 16S rRNA gene of strain AHB1 to that of N. multiformis C-71 was at least 98.5%. The different degree of sequence conservation between the 16S rDNA and the genes encoding for ammonia monooxygenase facilitates the application of the latter as a molecular tool for a fine-scale differentiation of autotrophic nitrifying bacteria, at the species or strain level, in both environmental and cultivation studies.
Amino Acid Sequence↗
Effect of acid suppression on efficacy of treatment for Helicobacter pylori infection.
Eradication of Helicobacter pylori from the stomach by triple therapy with bismuth, tetracycline, and metronidazole cures peptic ulcer disease. We investigated whether concomitant acid inhibition with omeprazole would improve the results of triple therapy. 108 consecutive patients with peptic-ulcer disease and biopsy-proven H pylori infection were randomised to 7 days of triple therapy with or without omeprazole 20 mg twice daily. Patients in the omeprazole-treated group were pretreated with 3 days of omeprazole. Eradication of H pylori was assessed by 10 endoscopic biopsies for urease test, histology, and culture 4-6 weeks after treatment. 53 of 54 (98.1%) patients treated with omeprazole were cured compared with 45 of 54 (83.3%) of those not treated (p = 0.02), a difference in efficacy of 14.8% (95% Cl 4.2-25.4%). Most side effects were mild and did not interfere with compliance; 105 patients (97.2%) finished treatment. Gastro-intestinal side effects were significantly fewer in the omeprazole group. We conclude that the addition of omeprazole to triple therapy improves efficacy, lessens side effects, and is sufficiently efficacious to obviate the need for a diagnostic test of cure in compliant patients.
Adult↗
Lung transplantation in The Netherlands: first results of the medical technology assessment.
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Adult↗
Quantitative Determination of the Spatial Distribution of Nitrosomonas europaea and Nitrobacter agilis Cells Immobilized in kappa-Carrageenan Gel Beads by a Specific Fluorescent-Antibody Labelling Technique.
A novel technique, combining labelling and stereological methods, for the determination of spatial distribution of two microorganisms in a biofilm is presented. Cells of Nitrosomonas europaea (ATCC 19718) and Nitrobacter agilis (ATCC 14123) were homogeneously distributed in a kappa-carrageenan gel during immobilization and allowed to grow out to colonies. The gel beads were sliced in thin cross sections after fixation and embedding. A two-step labelling method resulted in green fluorescent colonies of either N. europaea or N. agilis in the respective cross sections. The positions and surface areas of the colonies of each species were determined, and from that a biomass volume distribution for N. europaea and N. agilis in kappa-carrageenan gel beads was estimated. This technique will be useful for the validation of biofilm models, which predict such biomass distributions.
Journal Article↗
Isolation and structure determination of the intact sialylated N-linked carbohydrate chains of recombinant human follitropin expressed in Chinese hamster ovary cells.
Biologically active recombinant human follitropin has been expressed in Chinese hamster ovary cells. The carbohydrate chains of the recombinant glycoprotein hormone were enzymatically released by peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F. The oligosaccharides were separated from the N-deglycosylated protein by gel-permeation chromatography on Bio-Gel P-100, and fractionated by a combination of FPLC on Mono Q and HPLC on Lichrosorb-NH2. The structures of the carbohydrate chains were determined by 500- or 600-MHz 1H-NMR spectroscopy. The following types of carbohydrates occur: monosialylated diantennary (10%), disialylated diantennary (43%), disialylated tri-antennary (5%), trisialylated tri-antennary (13%), trisialylated tri'-antennary (8%), and tetrasialylated tetraantennary (12%) N-acetyllactosamine type of carbohydrate chains, all bearing exclusively alpha 2-3-linked N-acetylneuraminic acid (Neu5Ac). Previously, for pituitary follitropin mono-, di-, tri-, tri'-, and tetra-antennary oligosaccharides containing alpha 2-3- as well as alpha 2-6-linked Neu5Ac residues were reported. The bisecting GlcNAc residues present in native follitropin were not detected in the recombinant glycoprotein. Of the oligosaccharides 29% have an alpha 1-6-linked Fuc residue at the asparagine-bound GlcNAc, whereas this amount is about 50% in pituitary follitropin. In some of the tri-, tri'- and tetra-antennary oligosaccharide fractions small amounts (less than 5%) of compounds were detected having one or more additional N-acetyllactosamine units.
Animals↗
Structure and function of the androgen receptor.
The androgen receptor in several species (human, rat, calf) is a monomeric protein with a molecular mass of 100-110 kDa. The steroid binding domain is confined to a region of 30 kDa, while the DNA-binding domain has the size of approx. 10 kDa. A 40 kDa fragment containing both the DNA and steroid binding domain displayed a higher DNA binding activity than did the intact 100 kDa molecule. cDNA encoding the major part of the human androgen receptor was isolated. The cDNA contains an open reading frame of 2,277 bp but still lacks part of the 5'-coding sequence. Homology with the progesterone and glucocorticoid receptor was about 80% in the DNA binding domain and 50% in the steroid binding domain. The present data provide evidence that the androgen receptor belongs to the superfamily of ligand responsive transcriptional regulators and consists of three distinct domains each with a specialized function.
Amino Acid Sequence↗
Mechanism of androgen action: recent observations on the domain structure of androgen receptors and the induction of EGF-receptors by androgens in prostate tumor cells.
In this paper two different aspects of androgen action are reviewed. Polyacrylamide gel electrophoresis of androgen receptors, photoaffinity labeled with R1881 showed that receptors isolated from both human prostate cells and calf uterine cytosol cells are proteins with a molecular mass of approx 110 kD. Purification to homogeneity of this form of the receptor from calf uterus also yielded a 110 kD protein. A molecular model for the DNA-binding form of the receptor is presented in which one polypeptide comprises three active domains: one for ligand binding, one for interaction with nuclear acceptor sites, and a third domain which modulates nuclear interaction. Mild digestion with chymotrypsin or a protease from rat prostates removes the modulating domain and leaves the ligand binding and nuclear interaction domain intact. Trypsin treatment yields a fragment of lower molecular mass containing the ligand binding domain with some affinity for RNA, but not DNA. In vitro studies with a human prostate tumor cell line (LNCaP), suggest that androgens not only directly effect cell growth, but also act indirectly. Both epidermal growth factor (EGF) and androgens stimulate cell growth. In addition androgens stimulate synthesis of receptors for EGF. Thus androgens effect tumor cell growth by autocrine or paracrine mechanisms by making the cells more sensitive for growth factor mediated stimuli.
Androgens↗
Transformation (4S to 5S) of the nuclear estrogen receptor is reversible but not accompanied by a change in the affinity for DNA.
The nuclear estrogen receptor from calf uterus was used to investigate the possible relationship between receptor transformation (4S to 5S) and receptor activation (DNA binding). Receptors extracted from nuclei after exposure of uterine tissue tc [3H]estradiol sedimented at 5.2S, the characteristic value of the transformed receptor. After storage at -20 degrees C the receptor sedimented at 4.0S, indicating conversion of the 5S form into the non-transformed 4S form. Upon reincubation at 28 degrees C the 4S form transformed into the 5S form following second-order kinetics. The rate constant obtained was 4.3 x 10(7) M-1 min-1, a value identical to that reported for the cytosol receptor. These data show that receptor transformation is reversible. Molybdate (10-50 mM) was not able to prevent receptor transformation in the nuclear extract, but was inhibitory in cytosol. This suggests that molybdate does not prevent receptor transformation, but rather inhibits disaggregation of the 8S oligomer into the 4S monomer. In DNA-binding assays (DNA-cellulose or nuclei) the non-transformed (4S) and transformed (5S) states of the nuclear estrogen receptors displayed identical affinities for DNA. The present data show that 4S to 5S transformation of nuclear receptors follows a readily reversible process, but this process is not an essential step for the exposure of the receptors' DNA-binding site. Although the physiological function of the 5S form remains unclear it may be important for the recognition of specific gene regulatory sites.
Animals↗