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Biomedical subjects

J Oliver

Publications and source records attributed to J Oliver.

At least 19 recordsLinked to original sources
PubMed1992

The molecular defect in a family with mild atypical osteogenesis imperfecta and extreme joint hypermobility: exon skipping caused by an 11-bp deletion from an intron in one COL1A2 allele.

We have investigated a family with an autosomal dominantly inherited connective-tissue defect causing extreme joint hypermobility, premature osteoporosis and late-onset fractures. Analysis of collagenous proteins from affected individuals showed a deletion in some alpha 2(I) chains. Peptide mapping localized this to the CB peptide alpha 2CB4, which covers the N-terminal one-third of the protein chain. Polymerase chain reaction amplification and sequencing of cDNA derived from this region of the mRNA identified a heterozygous deletion of the 54 bp comprising exon 9. Similar analysis of the genomic DNA revealed an 11-bp deletion from bp3 to bp13 of IVS-9. This disrupts the consensus 5' splice signal (GTAAGT) and leads to exon skipping. In a family study of 13 affected and unaffected family members using both heteroduplex formation and direct analysis for the deletion, all of the affected, but no unaffected individuals, were found to carry the deletion. This generated a positive Lod score of 2.6 with the Liped programme.

Alleles↗
PubMed1992

Studies on the surface phenotype and functions of dendritic cells in parenchymal lung tissue of the rat.

Immunohistochemical analysis of frozen sections of rat lung tissue identified a widely distributed population of highly pleiomorphic Ia+ cells in alveolar septal walls, which are negative for the pan-macrophage marker ED4 and the related markers ED1, ED2 and ED9. Semi-purified dendritic cells (DC) prepared from lungs of rats exposed to an aerosol of ovalbumin (OA) triggered modest levels of proliferation of OA-immune T cells in vitro, demonstrating the potential of these cells in surveillance for inhaled antigens in vivo. Lung wall also exhibited modest stimulatory activity in mixed lymphocyte/leucocyte reaction (MLR) assays. Overnight incubation of the DC in T-cell culture supernatant markedly increased their T-cell stimulatory properties, concomitant with increased expression of Ia. These results suggest that analogous to epidermal Langerhans' cells, lung wall DC can effectively bind inhaled antigens in situ, but require additional maturation/activation signals before they can efficiently present the antigen to T cells.

Animals↗
PubMed1991

Preliminary investigation of crystals of the neutral lipase from Pseudomonas fluorescens.

The neutral lipase from the bacteria Pseudomonas fluorescens, marketed under the trade name LpL-200S, has been crystallized in a form suitable for X-ray diffraction analysis from 35% n-propanol at pH 8.5. The crystals are monoclinic prisms and are of space group C2 with a = 91.00 A, b = 47.17 A, c = 35.21 A and beta = 121.43 degrees. There is one molecule of the protein as the asymmetric unit of the crystals. The diffraction pattern extends to at least 1.6 A resolution and the crystals are extremely robust in terms of X-ray exposure.

Crystallization↗
PubMed1991

Preparation of representative homogenates of biological tissues: effect of salt on protein extraction.

A technique for the preparation of representative homogenates of tissues is described. For most soft tissues and biological fluids (liver, kidney, semen) more than 80% of protein was recovered after homogenization in isotonic buffer. With tissues that are harder to homogenize, such as heart, spleen, and skeletal muscle, however, only approximately 40-50% of protein was extracted in this medium. Inclusion of salt or salt plus detergent during the homogenization increased recovery of the protein to levels close to those recorded with soft tissues. The increase represented a true recovery and was not an artifact induced by salt/detergent. This situation is parallel to previously reported results for lipid-rich biological tissues.

Animals↗
PubMed1991

Studies on the density, distribution, and surface phenotype of intraepithelial class II major histocompatibility complex antigen (Ia)-bearing dendritic cells (DC) in the conducting airways.

Conventional immunohistochemical analysis of airway intraepithelial class II major histocompatibility complex (Ia) expression demonstrates a morphologically heterogeneous pattern of staining, suggestive of the presence of a mixed population of endogenous antigen presenting cells. Employing a novel tissue sectioning technique in conjunction with optimal surface antigen fixation, we now demonstrate that virtually all intraepithelial Ia staining throughout the respiratory tree in the normal rat, can be accounted for by a network of cells with classical dendritic cell (DC) morphology. The density of DC varies from 600-800 per mm2 epithelial surface in the large airways, to 75 per mm2 in the epithelium of the small airways of the peripheral lung. All the airway DC costain for CD4, with low-moderate expression of a variety of other leukocyte surface markers. Both chronic (eosinophilic) inflammation and acute (neutrophilic) inflammation, caused respectively by inhalation of chemical irritants in dust or aerosolised bacterial lipopolysaccharide (LPS), are shown to be accompanied by increased intraepithelial DC density in the large airways (in the order of 50%) and up to threefold increased expression of activation markers, including the beta chain of CD11/18. The kinetics of the changes in the DC network in response to LPS mirrored those of the transient neutrophil influx, suggesting that airway intraepithelial DC constitute a dynamic population which is rapidly upregulated in response to local inflammation. These findings have important theoretical implications for research on T cell activation in the context of allergic and infectious diseases in the respiratory tract.

Animals↗
PubMed1991

Structure of human glutathione S-transferase class Mu genes.

Nucleotide sequencing of a human cosmid clone shows that the exon-intron structures of a glutathione S-transferase multigene family are conserved between man and rat, that the human gene family is clustered and that gene conversion events have occurred within the cluster. In addition, between man and rat, there is a high degree of nucleotide sequence identity not only in exons but also in some introns. These conserved sequences are coincident with homologous sequences subject to gene conversion in both species, and hence the utilization of gene conversion by this gene family has itself been conserved. By using transient-expression assay the conserved/converted regions are shown to be capable of modulating transcriptional activity. The data suggest that DNA repair by gene conversion may be a chemical immunity mechanism. which could result in acquired resistance to toxins and, in particular, drug resistance due to glutathione S-transferase in tumours.

Amino Acid Sequence↗
PubMed1991

The mechanisms of action of lithium. I. Effects on serotoninergic and noradrenergic systems in normal subjects.

The effects of 2 weeks of lithium carbonate administration at therapeutic plasma levels were examined in 11 normal volunteers. Serotoninergic function before and after lithium administration was assessed using low-dose intravenous clomipramine hydrochloride challenge, while urinary and plasma metabolites of norepinephrine (NE) were used to assess noradrenergic systems. Long-term lithium administration in normal subjects did not significantly or consistently enhance serotonin-mediated neuroendocrine responses but did increase measures related to neuronal release of NE. No statistically significant effects of lithium on prolactin, corticotropin, or cortisol responses to serotoninergic challenge could be detected. The probability of a type II error was assessed, and a doubling of prolactin level was unlikely to have been missed, although more modest increases (less than 75%) could have been overlooked. After 2 weeks of lithium administration, there were significant increases in 24-hour urinary excretion of NE, normetanephrine, and fractional NE release, compatible with increased neuronal release of NE and a lithium-induced subsensitivity in alpha 2-adrenergic receptor function. These changes were not statistically significant after 1 week of administration, suggesting that increased NE release is characteristic of long- rather than short-term lithium administration. Since previous reports have demonstrated enhanced prolactin responses after short- but not long-term lithium use, the present study points to temporal specificity in lithium's effects on both serotoninergic and noradrenergic function. Lithium's effects on NE release were consistent but small (a 16% increase), while its effects on serotoninergic responses were larger (a 50% increase in prolactin responses) but quite inconsistent, suggesting that neither of these systems is the primary site of action of lithium.

Adrenocorticotropic Hormone↗
PubMed1991

Acute myocardial infarction after blunt chest trauma in young people: need for prompt intervention.

We describe four cases of acute myocardial infarction in young patients, secondary to blunt chest trauma. One case was treated with intracoronary thrombolysis and angioplasty, two cases received systemic thrombolysis, and the last one did not have any reperfusion therapy. The coronary angiograms of the left anterior descending artery showed thrombosis in two cases, coronary dissection in one case, and no morphological lesions in the other. We encourage the early performance of angiographic studies in these patients, adjusting the therapy to their pathophysiologic mechanism.

Accidents, Traffic↗
PubMed1991

Regulation of immune response to inhaled antigen by alveolar macrophages: differential effects of in vivo alveolar macrophage elimination on the induction of tolerance vs. immunity.

A single intratracheal instillation of liposomes containing dichloro methylene diphosphonate into rats eliminated greater than 80% of the alveolar macrophage (AM phi) population, and the population was not significantly renewed during the ensuing week. AM phi depletion markedly increased local antibody production in the lung wall in pre-primed animals exposed to antigen aerosols. However, AM phi depletion did not affect the normal development of protective tolerance (particularly in the IgE antibody class) to inhaled antigen in immunologically naive rats. These results are discussed in relation to regional control of immune responses in the upper vs. the lower respiratory tract.

Aerosols↗
PubMed1991

Ehlers-Danlos syndrome type VII: a single base change that causes exon skipping in the type I collagen alpha 2(I) chain.

We have examined the procollagens and collagens produced by skin fibroblasts from a patient with Ehlers-Danlos syndrome type VII. The patient was heterozygous for an abnormal alpha 2(I) chain migrating with the approximate size of pN alpha 2(I) chains after pepsin digestion. Peptide mapping suggested that the abnormality was located at the amino-terminus of the alpha 2(I) chain. Quantitative analysis of the alpha 2(I) mRNA indicated loss of the exon 6 sequences, and subsequent polymerase chain reaction amplification of cDNA demonstrated a deletion of the 54 bp of exon 6 from some of the alpha 2(I) mRNA. Analysis of genomic DNA from the patient revealed a single base change in one COL1A2 allele, substituting an A for a G as the first base of intron 6. This change mutates the obligate GT-dinulceotide splicing signal to AT and leads to exon skipping with splicing from exon 5 to exon 7. Loss of exon 6 sequences results in the loss of the procollagen-N-propeptidase cleavage site and a lysine residue that normally participates in covalent intermolecular crosslinking within collagen fibres.

Adult↗
PubMed1991

Cockroach allergenic activity: analysis of commercial cockroach and dust extracts.

Previous investigations demonstrated that cockroach whole bodies and feces are important sources of allergens in the induction/exacerbation of bronchial asthma. The current study investigated different cockroach source materials, commercial extracts, and house dust extracts for cockroach allergenic activity. In general, extracts from four different sources of either American or German cockroaches contained similar amounts of allergenic activity by RAST inhibition. Three commercial American cockroach extracts compared by RAST inhibition had similar allergenic activity on an equal protein basis. Skin test results correlated house dust reactivity to both commercial and inhouse cockroach wholebody extracts and to fecal extracts. Six different samples of house dust obtained from vacuum cleaners in the New Orleans area and three commercially obtained house dust extracts contained varying quantities of cockroach allergenic activity by RAST inhibition. These studies demonstrate that commercial cockroach extracts vary in allergenic activity and that all house dust extracts tested contain cockroach allergens.

Allergens↗
PubMed1991

Kinetic characterization of phosphofructokinase isolated from rat kidney cortex.

1. Phosphofructokinase from rat kidney cortex has been purified by affinity chromatography to a final specific activity of 15 units per mg of protein, measured at 25 degrees C and pH 8. 2. This lower spec. act., compared with that of the enzyme from other sources, shows the enzyme in proximal tubules to be less active, which would account for the main gluconeogenic role of these nephron sections. 3. The binding of fructose-6-phosphate to the enzyme is co-operative. ATP increases the Hill coefficient and produces a marked allosteric inhibition on the activity. 4. Fructose-2,6-bis-phosphate is a potent activator of the enzyme from this source. It reduces the Hill coefficient of the enzyme and the inhibition constant of ATP. A marked difference between this and the liver enzyme is that the activation is not co-operative.

Adenosine Triphosphate↗
PubMed1991

Distribution of arrestin-like protein and beta-subunit of GTP-binding proteins in quail choroid plexuses.

Monoclonal antibodies (Mabs) directed against retinal arrestin (S-antigen) were used to detect and characterize this protein in choroid plexus (CP) of quails maintained during eight days, either under long-day photoperiods or in constant darkness. Immunocytochemistry and Western blotting confirmed the presence and the distribution of an arrestin-like protein in quail CP. Arrestin-like immunoreactivities in CP were compared with those obtained with Mabs to beta 36-subunit of G proteins (G beta), alpha-subunit of transducin and rhodopsin. Rhodopsin-like and transducin-like proteins could not be detected in choroidal cells, whereas intense positive reactions were observed with anti-G beta and anti-arrestin Mabs. The strongest immunoreactivities were found in choroidal ependymocytes of the lateral and IIIrd ventricles. In CP epithelial cells lining the IVth ventricle, very weak or no immunoreactivity could be detected with Mabs to arrestin, while Mab against G beta subunit always provided a positive reaction. In quails maintained in constant darkness, arrestin- and G beta-immunoreactivities of CP epithelial cells displayed changes in cellular distribution and intensity (decrease or disappearance of the immunoreactions). The strong arrestin-like immunoreaction located in the apical region of ependymocytes suggests the preferential association of the protein with choroidal microvilli and a possible role in cerebrospinal fluid production assumed by CP cells.

Animals↗
PubMed1991

Distribution of pyruvate carboxylase along the rat nephron: an immunological and enzymatic study.

Antibodies against purified rat-kidney-cortex pyruvate carboxylase were raised in rabbits. These polyspecific antibodies recognize pyruvate carboxylase enzymes alone without cross reactivity with other carboxylases as detected by immunoblotting. The abundance of pyruvate carboxylase in the various renal fractions was measured by ELISA and its activity by the fixation of [14C]CO3H-. The results were corroborated by a combination of immunocytochemistry and transmission electron microscopy. A good correlation was found between the enzymatic activity and the quantity of enzyme contained in each fraction. The kidney-cortex pyruvate carboxylase was primarily located in proximal tubules, in accord with its important role in gluconeogenesis.

Animals↗
PubMed1991

Substitution of cysteine for glycine at residue 415 of one allele of the alpha 1(I) chain of type I procollagen in type III/IV osteogenesis imperfecta.

We have examined the type I collagen in a patient with type III/IV osteogenesis imperfecta. Two forms of alpha 1(I) chain were produced, one normal and the other containing a cysteine residue within the triple helical domain of the molecule. Cysteine is not normally present in this domain of type I collagen. Peptide mapping experiments localised the mutation to peptide alpha 1(I)CB3 which spans residues 403 to 551 of the triple helix. Subsequent PCR amplification of cDNA covering this region followed by sequencing showed a G to T single base change in the GGC codon for glycine 415 generating TGC, the codon for cysteine. The effect of the mutation on the protein is to delay secretion from the cell, reduce the thermal stability of the molecule by 2 degrees C, and cause excessive post-translational modification of all chains in molecules containing one or more mutant alpha 1(I) chains. The clinical phenotype observed in this patient and the position of the mutation conform to the recent prediction of Starman et al that Gly----Cys mutations in the alpha 1(I) chain have a gradient of severity decreasing from the C-terminus to the N-terminus.

Alleles↗
PubMed1991

Regulation of IgE responses to inhaled antigens: cellular mechanisms underlying allergic sensitization versus tolerance induction.

Previous research from our laboratory has established that the natural response of the respiratory mucosal immune system to inhaled allergens involves initial 'recognition' accompanied by transient low-level IgE production, followed by the development of protective immunological tolerance. Recent studies indicate that the crucial cellular events in this process occur at the level of the upper respiratory mucosa and in the local draining lymph nodes. Salient findings from ongoing studies, detailed below, include identification of a highly developed network of dendritic antigen-presenting cells within the airway epithelium which trap inhaled antigen, and definition of the surface phenotype of the suppressor T cells mediating tolerance as TcR gamma + delta +.

Administration, Oral↗