Biomedical subjects

P de Wilde

Publications and source records attributed to P de Wilde.

12 recordsLinked to original sources

PubMed1998

[Kimura's disease].

An Asian man aged 42 had a pre-auricular swelling on the left with local skin itching. Owing to the highly probably benign nature at examination, surgical treatment was refrained from. One year later, the swelling had increased while the itching was unchanged, so that surgical excision was performed. Morbid-anatomical examination revealed angiolymphoid hyperplasia with eosinophilia, compatible with Kimura's disease. Kimura's disease is a chronic inflammatory disorder which is very rare in Europe, but which is frequently diagnosed in Asian countries and in immigrants from these countries. Tumours in the head and neck region, enlarged lymph nodes and increased eosinophil counts are typical signs. The IgE level is increased. The cause of this disease is so far not clear, although there are indications that an inflammatory reaction to an unknown allergen plays a part. It is essential that this disease should be distinguished in the diagnostic work-up from presence of a malignancy. Fine-needle aspiration cytology is often inconclusive; as a rule the diagnosis can only be made after surgical excision of the tumour. There is no consensus on the treatment of this disease, but symptomatic therapy usually suffices.

Adult↗

PubMed1998

The Rhizobium sp. BR816 nodD3 gene is regulated by a transcriptional regulator of the AraC/XylS family.

Rhizobium sp. BR816 contains four nodD alleles of which nodD3 is the most important transcriptional regulator for nodulation of Phaseolus vulgaris. Upstream of nodD3 an open reading frame, orf816, was identified. The deduced ORF816 protein shows homology with transcriptional regulators of the AraC/XylS family. The DNA binding domain and the consensus motif, characteristic of the C-terminal region of the members of this family of transcriptional regulators, are present in the deduced ORF816 protein. Activation of nodA gene expression and nodulation of P. vulgaris by Rhizobium sp. NGR234nodD1::omega (Nod-) complemented with the Rhizobium sp. BR816 nodD3 gene were significantly increased in the presence of orf816. This increased nodulation and nod gene induction are mediated through positive regulation of nodD3 expression by ORF816. Expression of orf816 itself is partially RpoN dependent. The role of this transcriptional regulator in the complex cascade regulation of the Rhizobium sp. nodD3 gene is discussed.

AraC Transcription Factor↗

PubMed1998

The Rhizobium etli rpoN locus: DNA sequence analysis and phenotypical characterization of rpoN, ptsN, and ptsA mutants.

The rpoN region of Rhizobium etli was isolated by using the Bradyrhizobium japonicum rpoN1 gene as a probe. Nucleotide sequence analysis of a 5,600-bp DNA fragment of this region revealed the presence of four complete open reading frames (ORFs), ORF258, rpoN, ORF191, and ptsN, coding for proteins of 258, 520, 191, and 154 amino acids, respectively. The gene product of ORF258 is homologous to members of the ATP-binding cassette-type permeases. ORF191 and ptsN are homologous to conserved ORFs found downstream from rpoN genes in other bacterial species. Unlike in most other microorganisms, rpoN and ORF191 are separated by approximately 1.6 kb. The R. etli rpoN gene was shown to control in free-living conditions the production of melanin, the activation of nifH, and the metabolism of C4-dicarboxylic acids and several nitrogen sources (ammonium, nitrate, alanine, and serine). Expression of the rpoN gene was negatively autoregulated and occurred independently of the nitrogen source. Inactivation of the ptsN gene resulted in a decrease of melanin synthesis and nifH expression. In a search for additional genes controlling the synthesis of melanin, an R. etli mutant carrying a Tn5 insertion in ptsA, a gene homologous to the Escherichia coli gene coding for enzyme I of the phosphoenolpyruvate:sugar phosphotransferase system, was obtained. The R. etli ptsA mutant also displayed reduced expression of nifH. The ptsN and ptsA mutants also displayed increased sensitivity to the toxic effects of malate and succinate. Growth of both mutants was inhibited by these C4-dicarboxylates at 20 mM at pH 7.0, while wild-type cells grow normally under these conditions. The effect of malate occurred independently of the nitrogen source used. Growth inhibition was decreased by lowering the pH of the growth medium. These results suggest that ptsN and ptsA are part of the same regulatory cascade, the inactivation of which renders the cells sensitive to toxic effects of elevated concentrations of malate or succinate.

Amino Acid Sequence↗

PubMed1997

Isolation and characterization of the Azospirillum brasilense trpE(G) gene, encoding anthranilate synthase.

The Azospirillum brasilense trpE gene has been isolated by DNA hybridization and by genetic complementation of an Escherichia coli trpE deletion mutant. DNA sequence analysis of a 3.1-kb PstI restriction fragment of A. brasilense revealed the presence of an open reading frame encoding a putative TrpE(G) fusion protein. Previously an A. brasilense clone containing trpGDC was identified (Zimmer et al. Mol Gen Genet 229:41-51, 1991). It can, therefore, be concluded that A. brasilense contains two trpG genes. A putative leader peptide is found upstream of trpE(G), containing three consecutive tryptophan residues. Putative terminator and anti-terminator loops have also been identified. The LLESX10S motif, which is responsible for feedback inhibition by tryptophan in other TrpE proteins, is absent in the A. brasilense TrpE(G) fused protein.

Amino Acid Sequence↗

PubMed1997

HoxA is a transcriptional regulator for expression of the hup structural genes in free-living Bradyrhizobium japonicum.

A chromosomally integrated Bradyrhizobium japonicum hoxA mutant is unable to oxidize hydrogen in free-living conditions. Derepressing conditions that induce hydrogenase activity in free-living, wild-type B. japonicum cells cannot induce expression of the hydrogenase structural genes in the hoxA mutant. The DNA-binding capacity of HoxA at the hup promoter region was studied by means of gel retardation. Both heterotrophically growing cells and cells induced to express hydrogenase activity contain a protein that specifically binds to the hup promoter region. Crude protein extracts isolated from a B. japonicum hoxA mutant do not contain this binding compound. The HoxA protein was overexpressed in E. coli and isolated in the form of a maltose-binding protein (MBP)-HoxA fusion. The MBP-HoxA hybrid protein specifically bound to a 50 bp region of the hupSL promoter known to be important for regulation of hupSL expression.

Bacterial Proteins↗

PubMed1997

The arginine deiminase pathway in Rhizobium etli: DNA sequence analysis and functional study of the arcABC genes.

Sequence analysis upstream of the Rhizobium etli fixLJ homologous genes revealed the presence of three open reading frames homologous to the arcABC genes of Pseudomonas aeruginosa. The P. aeruginosa arcABC genes code for the enzymes of the arginine deiminase pathway: arginine deiminase, catabolic ornithine carbamoyltransferase (cOTCase), and carbamate kinase. OTCase activities were measured in free-living R. etli cells and in bacteroids isolated from bean nodules. OTCase activity in free-living cells was observed at a different pH optimum than OTCase activity in bacteroids, suggesting the presence of two enzymes with different characteristics and different expression patterns of the corresponding genes. The characteristics of the OTCase isolated from the bacteroids were studied in further detail and were shown to be similar to the properties of the cOTCase of P. aeruginosa. The enzyme has a pH optimum of 6.8 and a molecular mass of approximately 450 kDa, is characterized by a sigmoidal carbamoyl phosphate saturation curve, and exhibits a cooperativity for carbamoyl phosphate. R. etli arcA mutants, with polar effects on arcB and arcC, were constructed by insertion mutagenesis. Bean nodules induced by arcA mutants were still able to fix nitrogen but showed a significantly lower acetylene reduction activity than nodules induced by the wild type. No significant differences in nodule dry weight, plant dry weight, and number of nodules were found between the wild type and the mutants. Determination of the OTCase activity in extracts from bacteroids revealed a strong decrease in activity of this enzyme in the arcA mutant compared to the wild-type strain. Finally, we observed that expression of an R. etli arcA-gusA fusion was strongly induced under anaerobic conditions.

Acetylene↗

PubMed1996

Different La/SS-B mRNA isoforms are expressed in salivary gland tissue of patients with primary Sjögren's syndrome.

Recently we isolated a La/SS-B mRNA isoform from a cDNA library made from peripheral blood lymphocytes of a patient with primary Sjögren's Syndrome. In the La/SS-B mRNA isoform the exon 1 was replaced. The alternative exon was termed exon 1'. Genomic analysis showed that the exon 1' La mRNA was the result of a promoter-switch in combination with alternative splicing. Due to the unusual structure of the exon 1' La/SS-B mRNA, the function and the behaviour under physiological and pathophysiological conditions in tissue of patients with primary Sjögren's syndrome or Systemic Lupus Erythematosus remained obscure. Therefore assays were established allowing a qualitative and quantitative estimation of expression of the exon 1 and 1' La mRNA form, including in situ and dot blot hybridization as well as reversed PCR. Both mRNA forms were found to represent finally processed cytoplasmic mRNAs belonging to the abundant class of mRNAs. They were expressed and regulated in parallel. A ratio exon 1 to 1' between 1:1 and 5:1 was determined. Both mRNA forms were downregulated in quiescent cells and upregulated in activated and proliferating cells including non-keratized stratified squamous epithelial, endothelial, salivary gland as well as infiltrating cells.

Autoantigens↗

PubMed1996

Early electrocardiographic signs in acute massive pulmonary embolism.

As a result of the increasing accuracy in diagnosing acute pulmonary embolism by isotopic ventilation-perfusion scintigraphy and pulmonary arterial angiography, the electrocardiographic changes associated with acute cor pulmonale are being abandoned as a diagnostic tool for this life-threatening disease. Nevertheless, certain electrocardiographic findings can raise the suspicion of pulmonary embolism. In our view the electrocardiogram does have some merits in the emergency work-up of a patient with a high suspicion of pulmonary embolism. In this case report we emphasize the importance of the electrocardiographic findings which forwarded the diagnosis of pulmonary embolism. Hence the necessary invasive diagnostic and therapeutic measures, i.e. pulmonary arterial angiography and thrombolytic therapy, can be taken immediately after admission to the emergency department.

Acute Disease↗

PubMed1995

Induction of Plasmodium falciparum sporozoite-neutralizing antibodies upon vaccination with recombinant Pfs16 vaccinia virus and/or recombinant Pfs16 protein produced in yeast.

Pfs16 is a sexual stage/sporozoite-specific antigen of Plasmodium falciparum and is a potential candidate for a sporozoite-neutralizing vaccine. To obtain more information on the function of Pfs16 and to investigate its role during transmission and hepatocyte invasion, immunization experiments were performed with both a Pfs16-specific recombinant vaccinia virus and virus-like particles produced in yeast composed of the hepatitis B surface antigen (HBsAg) and antigen Pfs16 fused to HBsAg. Upon transformation of yeast cells, harbouring a genomic copy of the HBsAg gene, with a plasmid carrying the fusion gene Pfs16-HBsAg (Pfs16-S) virus-like hybrid particles composed of HBsAg and Pfs16-S were formed of a size similar to those present in human sera after infection with the hepatitis B virus. Cells infected with recombinant Pfs16 vaccinia virus synthesized a polypeptide of approx. 16 kDa that reacted with a Pfs16-specific polyclonal antibody. Animals vaccinated with the yeast hybrid particles and/or recombinant vaccinia virus both produced Pfs16-specific antibodies. These antibodies showed no transmission-blocking activity, but they efficiently diminished or abolished in vitro invasion of sporozoites into human hepatoma cells (HepG2-A16) and primary human hepatocytes.

Amino Acid Sequence↗

PubMed1993

Selective laryngeal abductor reinnervation in cats using a phrenic nerve transfer and ORG 2766.

Reinnervation of the recurrent laryngeal nerve following nerve injury often leads to laryngeal synkinesis. Selective reinnervation of adductor and abductor muscles might be able to avoid synkinesis. This study presents the results of selective abductor reinnervation in cats, using a phrenic nerve transfer to the recurrent laryngeal nerve and directing all reinnervating axons toward the abductor muscle. Simultaneously, a blind, placebo-controlled, pilot study was performed to evaluate the capacity of ORG 2766, administered subcutaneously (25 micrograms/kg per 48 hours), to facilitate reinnervation by stimulation of axon sprouting. Reinnervation surgery was performed in 10 cats. Postoperative evaluation included videolaryngoscopy, electromyography, histological examination, and quantification of reinnervating axons. Nine cats could be evaluated, of which eight demonstrated electromyographic and laryngoscopic activity as soon as 6 weeks following surgery. The one cat showing no abduction was found to have an inadequate nerve anastomosis and was marked as a surgical failure. After 10 weeks, near-normal or more than normal abduction was seen in the eight cats, and histological proof of reinnervation was obtained in seven of them; one cat could not be evaluated histologically owing to unsuccessful fixation. Although no conclusive evidence was obtained concerning the effect of ORG 2766, the tendencies found warrant further experiments with this compound on laryngeal reinnervation.

Adrenocorticotropic Hormone↗

PubMed1983

Oral granular cell lesions. An immunohistochemical study with emphasis on intermediate-sized filaments proteins.

Six cases of oral granular cell lesions were studied with respect to intermediate-sized filaments (IF), peanut lectin binding (PNL) and muramidase activity by means of the peroxidase antiperoxidase technique. The tumours included three granular cell myoblastomas of the tongue (GCM) two cases of congenital gingival granular cell tumour (CGGT) and one granular cell ameloblastoma (GCA). Every tumour studied showed intracytoplasmic PNL binding whereas muramidase was negative in all cases. Vimentin expression was demonstrated in the CGGT and to a lesser extent in the GCM, but was absent in the GCA which was positive for keratin. Desmin and glial fibrillary acidic protein (GFAP) were not present in any of the lesions. These data demonstrate that PNL binding might be considered to be a common feature of granular cells regardless of their histogenesis. Lysosomes are supposed to represent the intracellular binding sites for this marker. Moreover it is shown that histomorphological identity between the granular cells of CGGT and GCA does not signify identity in histogenesis since the former are of mesenchymal derivation while the latter, from their intermediate filament protein types appear to originate from epithelium.

Ameloblastoma↗

PubMed1979

Cardiac tamponade with renal failure due to hemangioma of the heart.

In a 18 year-old woman, an isolated benign hemangioma of the right atrium led to cardiac tamponade and acute renal failure. After 8 days of anuria, the tumor was excised and replaced by a pericardial patch. The persistence of severe renal shutdown necessitated further hemodialysis during 22 days postoperatively. The patient was discharged on the 45th day in good hemodynamic and renal condition. Thirteen cases of benign hemangioma of the heart have been reported in the literature: 12 were found at autopsy; only 4 were complicated by hemopericardium but none of these survived.

Acute Kidney Injury↗