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Biomedical subjects

M Aubry

Publications and source records attributed to M Aubry.

At least 19 recordsLinked to original sources

Ross River virus transmission, infection, and disease: two and a half decades of research progress-an updated cross-disciplinary review.

SUMMARYRoss River virus (RRV) causes the most mosquito-borne disease notifications in Australia and a considerable burden of non-fatal, yet frequently prolonged rheumatic illness across the Australia-Pacific region, reflected in thousands of notifications each year and notable economic and quality-of-life losses. Research on RRV spans multiple disciplines, encompassing viral genomics, immunopathology, transmission ecology, epidemiology, entomology, and environmental science. This review synthesizes two decades of cross-disciplinary investigations to present an integrated perspective on the biological, clinical, ecological, and environmental dimensions of RRV infection. By consolidating findings from diverse fields, the review enhances understanding of the complex factors influencing RRV transmission and disease outcomes throughout its endemic range.

Humans

The KRAB zinc finger gene ZNF74 encodes an RNA-binding protein tightly associated with the nuclear matrix.

We previously cloned ZNF74, a developmentally expressed zinc finger gene commonly deleted in DiGeorge syndrome. Here, the intron/exon organization of the human gene and the functional properties of the expressed protein are presented. This zinc finger gene from the transcription factor IIIA/Kruppel family contains three exons. A truncated Kruppel-associated box (KRAB) located at the N terminus of the predicted 64-kDa zinc finger protein is encoded by exon 2. The remainder of the protein including the zinc finger domain as well as the 3'-untranslated region (UTR) is encoded by exon 3. Both 5'-UTR (exon 1) and 3'-UTR contain repetitive Alu elements. In vitro translation of a cDNA encoding the entire ZNF74 coding region produced a 63-kDa protein as determined on sodium dodecyl sulfate-polyacrylamide gel. A bacterially expressed fusion protein shown to bind tightly to 65zinc was used to test the nucleic acid binding properties of ZNF74. By RNA binding assays, ZNF74 was found to bind specifically to poly(U) and poly(G) RNA homopolymers. The restricted binding to these homopolymers and not to poly(A) and poly(C) suggested that ZNF74 displays RNA sequence preferences. RNA binding was mediated by the zinc finger domain. Immunofluorescence studies on transfected cells revealed ZNF74 nuclear localization. The labeling pattern observed in the nuclei clearly excluded the nucleoli. The zinc finger region lacks a classical nuclear localization signal but was found to be responsible for nuclear targeting. Subcellular and in situ sequential fractionations further showed that ZNF74 is associated with the nuclear matrix. The RNA binding properties of this protein and its tight association with the nuclear matrix, a subnuclear compartment involved in DNA replication as well as RNA synthesis and processing, suggest a role for ZNF74 in RNA metabolism.

Amino Acid Sequence

Excess of deletions of maternal origin in the DiGeorge/velo-cardio-facial syndromes. A study of 22 new patients and review of the literature.

We have determined the parental origin of the deleted chromosome 22 in 29 cases of DiGeorge syndrome (DGS) using a CA-repeat mapping within the commonly deleted region, and in one other case by using a chromosome 22 short arm heteromorphism. The CA-repeat was informative in 21 out of 29 families studied and the deleted chromosome was of maternal origin in 16 cases (72%). When these data are pooled with recent results from the literature, 24 de novo DGS, velo-cardio-facial syndrome (VCFS) and isolated conotruncal cardiac disease deletions are found to be of maternal origin and 8 of paternal origin, yielding a chi 2 of 8 with a probability level lower than 0.01. These data, and review of the literature on familial DGS/VCFS and isolated conotruncal cardiopathies suggest that there is a strong tendency for the 22q11.2 deletions to be of maternal origin.

Chromosome Deletion

Isolation of a zinc finger gene consistently deleted in DiGeorge syndrome.

DiGeorge syndrome is a human developmental disorder resulting in hypoplasia of the thymus and parathyroids, and conotruncal heart defects. We recently isolated four genes with zinc finger DNA binding motifs mapping to chromosome 22q11.2 DiGeorge critical region. We now report that one of them, ZNF74 gene, is hemizygously deleted in 23 out of 24 DiGeorge syndrome patients tested. ZNF74 mRNA transcripts are detected in human and mouse embryos but not in adult tissues. Sequence analysis of a corresponding cDNA reveals an an open reading frame encoding 12 zinc finger motifs of the Kruppel/TFIIIA type as well as N-terminal and C-terminal non-zinc finger domains. These results suggest that changes in the dosage of a putative transcription factor through ZNF74 hemizygous deletion may be critical for DiGeorge developmental anomalies.

Adolescent

Cloning of six new genes with zinc finger motifs mapping to short and long arms of human acrocentric chromosome 22 (p and q11.2).

Zinc finger genes encode proteins containing tandemly repeated zinc-mediated folded structures that are found in several transcriptional regulatory proteins. To identify new zinc finger genes, we have screened at low stringency human cosmid libraries enriched in chromosome 22 sequences with a probe derived from the finger region of the mouse Kruppel-like gene, mKr2. We identified 23 nonoverlapping human cosmids cross-hybridizing with the probe. All sequences obtained from cosmid subclones hybridizing with the probe revealed Kruppel-type consensus sequences. Hybridizations to somatic cell hybrid panels and to metaphase chromosomes revealed that 2 nonoverlapping zinc finger cosmids map to chromosome 22p and 4 map to 22q11.2. The 17 other nonoverlapping cosmids most likely map to other chromosomes. The short arms of acrocentric chromosomes are thought to encode only ribosomal RNA genes. Therefore, the identification of two zinc finger genes on chromosome 22p represents an unexpected finding of unknown significance. The four zinc finger genes that map to 22q11.2 are within the cat eye and DiGeorge syndrome regions and thus provide us with potential candidate genes for these developmental malformations.

Amino Acid Sequence

Tubulin is phosphorylated at tyrosine by pp60c-src in nerve growth cone membranes.

We show here that tubulin is the major in vivo substrate of the tyrosine-specific protein kinase pp60c-src in nerve growth cone membranes. Phosphotyrosine antibodies were used to demonstrate phosphotyrosyl residues in a subpopulation of alpha- and beta-tubulin that was highly enriched in a subcellular fraction of growth cone membranes from fetal rat brain. The presence of phosphotyrosine-modified isoforms of alpha- and beta-tubulin in vivo was confirmed by 32p labeling of rat cortical neurons in culture. Tubulin in growth cone membranes was phosphorylated at tyrosine in endogenous membrane phosphorylation reactions (0.068 mol phosphotyrosine/mol alpha-tubulin and 0.045 mol phosphotyrosine/mol beta-tubulin), and phosphorylation was specifically inhibited by antibodies directed against pp60c-src, which is localized in the growth cone membranes. pp60c-src was capable of directly phosphorylating tubulin as shown in immune complex kinase assays with purified brain tubulin. Phosphopeptide mapping revealed a limited number of sites of tyrosine phosphorylation in alpha- and beta-tubulin, with similar phosphopeptides observed in vivo and in vitro. These results reveal a novel posttranslational modification of tubulin that could regulate microtubule dynamics at the growth cone.

Animals

Monoclonal antibodies as probes for the transmembrane structure of neutral endopeptidase 24.11 ('enkephalinase').

The neutral endopeptidase (EC 3.4.24.11) ('enkephalinase') is a membrane-bound metalloendopeptidase that is present in large amounts in the microvilli of the kidney proximal tubules. By immunizing mice with purified rabbit kidney brush-border membranes, we have obtained four different monoclonal antibodies that recognize this enzyme in dot-blot and Western-blot assays and can be used for immunoprecipitation of neutral endopeptidase from crude kidney solubilizates. One of these monoclonal antibodies (2B12) allows the labeling of proximal tubule cells with colloidal gold particles. This monoclonal antibody also binds to native brush-border membrane vesicles (which are mostly in the right-side-out configuration) and recognizes an epitope which is destroyed after reduction and alkylation of the protein. By contrast, all three other monoclonal antibodies (21G10, 23B11 and 22E2) compete for another epitope of neutral endopeptidase that is not exposed at the extracytoplasmic surface either in intact cells or in sealed brush-border vesicles. Permeabilization of the vesicles with digitonin, however, restores the full binding activity. Binding of these antibodies is not altered by prior reduction and alkylation of the protein. Taken together, these results strongly suggest that the 2B12 monoclonal antibody binds a conformational epitope located on the ectodomain of the enzyme, whereas the three others (21G10, 23B11 and 22E2) bind to a common or to overlapping epitopes located on the cytosolic domain. These results also demonstrate unambiguously the transmembrane nature of neutral endopeptidase.

Animals

Determination of brush border membrane vesicle orientation using monoclonal antibodies recognizing extracytoplasmic and cytoplasmic domains of neutral endopeptidase-24.11.

A method for determination of the orientation and integrity of brush border membrane vesicles is described. The method takes advantage of the availability of two monoclonal antibodies, 23B11 and 2B12, which recognize a cytoplasmic and an extracytoplasmic domain, respectively, of the neutral endopeptidase-24.11. Specific binding of the antibodies to intact kidney brush border vesicles or to vesicles permeabilized by digitonin is detected by fluorescence using an anti-mouse immunoglobulin G-fluorescein isothiocyanate conjugate. The method allows discrimination between right side out, inside out, and unsealed vesicles. It requires limited amounts of material and can be completed the day of the brush border vesicle preparation. Application to rabbit kidney brush border membranes freshly prepared led to values of 89, 8, and 3% for right side out, inside out, and unsealed vesicles, respectively. Storage at low temperature was associated with a marked increase in the proportion of unsealed vesicles.

Animals

c-src gene product in developing rat brain is enriched in nerve growth cone membranes.

Differentiating rat neurons express high levels of the protooncogene product pp60c-src, a 60-kDa tyrosine kinase of unknown function encoded by c-src. pp60c-src was found to be concentrated at least 9-fold in membranes from a subcellular fraction of nerve growth cones, the motile tips of outgrowing neuronal processes. Indirect immunofluorescence staining of cultured chick retinal explants showed pp60c-src in neuronal growth cones and processes, with the antigen particularly concentrated in growth cones of long neurites. pp60c-src in growth cone membranes was an active tyrosine-specific protein kinase with elevated tyrosine-specific protein kinase activity and reduced electrophoretic mobility characteristic of the form of pp60c-src in central nervous system neurons. pp60c-src was present at lower levels in subcellular fractions from mature rat brain but synaptosomal membranes were not enriched. Preferential localization of an active form of pp60c-src in nerve growth cone membranes and persistence of pp60c-src in mature neurons suggest that this tyrosine kinase is important in growth cone-mediated neurite extension and synaptic plasticity.

Animals

The use of a monoclonal antibody for the rapid purification of kidney neutral endopeptidase ("enkephalinase") solubilized in octyl glucoside.

The neutral endopeptidase ("enkephalinase") of the rabbit brush border membrane has been purified to homogeneity by a rapid immunoaffinity method using a monoclonal antibody. In contrast with other methods used so far, a complete extraction of enkephalinase from the brush border membrane can be achieved with octyl glucoside, without loss of activity. The solubilized enzyme can be selectively separated from the other proteins in a single step using an immunoaffinity column consisting of the monoclonal antibody covalently linked to Sepharose CL-4B. It is demonstrated that enkephalinase can then be recovered in an active form by elution at low pH. The purified enzyme obtained by this method is completely inhibited by thiorphan and appears as a single 94,000 dalton protein after polyacrylamide gel electrophoresis under denaturing and reducing conditions.

Animals

[Study and treatment of erection disorders. Value of intracavernous injections].

A multidisciplinary study of 57 patients with erection disorders included in addition to standard examinations: clinical, hormonal, vascular using Doppler and nervous with determination of latency time of bulbocavernous reflex, evaluation of effects of intracavernous papaverine injections completed by a manometric study of cavernous body filing by perfusion. A clear positive result of the papaverine test is considered to reflect integrity of vascularization of corpus cavernosum structure, and renders value less the continuation of vascular investigations. The appearance of an almost normal but delayed erection requiring high-dose papaverine administration is interpreted as being due to insufficiency of arterial origin without anomaly of venous return. The absence of erection after papaverine injection, whether in the presence or absence of an increase in penis volume, results from excessive venous return, insufficient arterial supply or both. Absence of erection despite a cavernous perfusion of more than 70 ml/min is due to excessive venous return that requires localization by cavernography. The onset of erection during cavernous body filling eliminates excessive venous return and results from arterial insufficiency that necessitates pelvic arteriography. A therapeutic attitude of logical consequence is proposed.

Clinical Trials as Topic

[Comparative study on the digestion of radiolabelled vicilin, legumin and lectin of Pisum sativum in the rat].

Storage proteins, vicilin, legumin as well as the lectin, purified from pea seed proteins, were radiolabelled with [14C]- or [3H]-formaldehyde, then mixed with the pea flour which was incorporated in a liquid meal and given to rats through a gastric tubing. Radiolabelled casein (75% of the total proteins in the meal) and triolein were added to the meal and the animals were killed after 2 and 7 h. Samples were taken from the stomach and intestinal contents and from the intestinal mucosa and the liver. 2 h: gastric emptying and intestinal absorption from vicilin and legumin materials were as high as for casein. 7 h: in the colon contents an excess of labelled vicilin and legumin (2.9 and 2.6% of the radioactive dose from the meal) was observed compared to casein (1.5%). The pea lectin disappeared slowlier from the intestinal contents than did the three other radiolabelled proteins (2 h) which gave the highest radioactive materials in the livers. The lectin did not interact with the intestinal mucosa but it was less hydrolysed than the three other proteins tested and 15% of the dose reached the colon (7 h). This lectin could have been adsorbed on pancreatic enzymes such as a lipase, but radiolabelled triolein did not produce radioactive material in the colon, demonstrating that lectin or other pea proteins, in these experiments did not inhibit this lipase. Short-time experiments (2 h, 7 h) were sufficient to describe and compare the digestion of three radiolabelled pea proteins.

Animals

Homozygous hemoglobin Knossos (alpha 2 beta 227(B9) Ala----Ser): a new variety of beta (+)-thalassemia intermedia associated with delta (0)-thalassemia.

Hb Knossos (beta 27 (B9) Ala----Ser) is a recently discovered hemoglobin variant endowed with beta-thalassemic properties (1,2) We present the first homozygous cases. The propositus, a 19-year-old man is originally from northeast Algeria, but is unrelated to other Algerians who have hemoglobin Knossos. He has a beta(+)-thalassemia intermedia syndrome, including microcytic, hypochromic anemia, enlargement of the spleen, and an increase in the number of reticulocytes. The reduction of beta-chain synthesis is pronounced (alpha/non alpha:2.76). Whole cells containing Hb Knossos have a dramatically low oxygen affinity (P50:38 mm Hg). The propositus also has homozygous delta(0)-thalassemia. The chromosome carrying these mutations is characterized by the DNA haplotype I.

Adult

The production and characterization of a monoclonal antibody specific for the 94,000 dalton enkephalin-degrading peptidase from rabbit kidney brush border.

We have prepared a monoclonal antibody specific for a major 94,000 dalton protein from the brush border membrane of rabbit kidney cortex. The monoclonal antibody was used for the immunoaffinity purification of this protein after solubilization of brush border membranes with octylglucoside. The 94,000 dalton protein is a peptidase capable of cleaving the Gly3-Phe4 bond of methionine-enkephalin. Identification of this peptidase as a previously described 94,000 dalton enkephalinase of kidney cortex was confirmed by its sensitivity to EDTA and inhibitors such as thiorphan and phosphoramidon.

Aminopeptidases

[The multi-family approach to the psychiatric hospital].

The authors describe a clinical experiment of a year of multifamily pedagogical and therapeutic sessions in a psychiatric hospital. The families were those of inpatients, most of them psychotic. The theoretical frame was the systemic and contextual approach of the family. The experiment showed that this therapeutic level can be efficient and useful with families often described as rigid and closed to external interventions.

Family Therapy