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D H Jones

Publications and source records attributed to D H Jones.

At least 55 records · Page 3Linked to original sources
PubMed1998

Triggering in the mucopolysaccharidoses.

Upper limb dysfunction, particularly in relation to skeletal dysplasia and median nerve dysfunction, is well recognized in the mucopolysaccharidoses and mucolipidoses. This is of increasing importance because bone marrow transplantation has dramatically improved survival without changing the musculoskeletal manifestations. Triggering at the A1 pulley and more distally has been described in these patients. We report two such cases and four other patients who were noted to have triggering at the carpal tunnel in association with carpal tunnel syndrome. Five of the six patients consented to surgical intervention with favorable outcomes.

Adolescent↗
PubMed1998

Protective immunity induced by oral immunization with a rotavirus DNA vaccine encapsulated in microparticles.

DNA vaccines are usually given by intramuscular injection or by gene gun delivery of DNA-coated particles into the epidermis. Induction of mucosal immunity by targeting DNA vaccines to mucosal surfaces may offer advantages, and an oral vaccine could be effective for controlling infections of the gut mucosa. In a murine model, we obtained protective immune responses after oral immunization with a rotavirus VP6 DNA vaccine encapsulated in poly(lactide-coglycolide) (PLG) microparticles. One dose of vaccine given to BALB/c mice elicited both rotavirus-specific serum antibodies and intestinal immunoglobulin A (IgA). After challenge at 12 weeks postimmunization with homologous rotavirus, fecal rotavirus antigen was significantly reduced compared with controls. Earlier and higher fecal rotavirus-specific IgA responses were noted during the peak period of viral shedding, suggesting that protection was due to specific mucosal immune responses. The results that we obtained with PLG-encapsulated rotavirus VP6 DNA are the first to demonstrate protection against an infectious agent elicited after oral administration of a DNA vaccine.

Administration, Oral↗
PubMed1998

Oral delivery of micro-encapsulated DNA vaccines.

Oral delivery of vaccines is an attractive alternative to injection. It is a non-invasive procedure which allows access to the gut-associated lymphoid tissues (GALT). Immunisation at GALT results in mucosal immune responses, which may be of particular importance in protection against infection at mucosal surfaces, as well as systemic immune responses. Vaccine antigens can be protected in the gut by encapsulation in poly(DL-lactide-co-glycolide) (PLG) microparticles. Their uptake into the immune inductive tissues of the GALT is mediated by M cells, which selectively phagocytose particles less than 10 microns in diameter. We have developed a method for the PLG encapsulation of plasmid DNA. Encapsulated DNA, expressing the insect protein luciferase under the transcriptional control of the human cytomegalovirus immediate early promoter, was administered to mice by intraperitoneal injection or oral gavage. Intraperitoneal injection of encapsulated DNA elicited good serum IgG and IgM responses and a modest IgA response. Oral administration stimulated good serum antibody titres in all three classes, and in addition, significant levels of mucosal IgA. PLG encapsulation thus has the ability to protect plasmid DNA against degradation after administration, and to facilitate its uptake into appropriate cells for the subsequent expression and presentation of antigen, in such a way as to elicit both systemic and mucosal antibody responses. This may have major implications for the design of novel vaccines and delivery strategies.

Administration, Oral↗
PubMed1997

Embryonic expression of the putative gamma subunit of the sodium pump is required for acquisition of fluid transport capacity during mouse blastocyst development.

The sodium/potassium pump, Na+,K+-ATPase, is generally understood to function as a heterodimer of two subunits, a catalytic alpha subunit and a noncatalytic, glycosylated beta subunit. Recently, a putative third subunit, the gamma subunit, was cloned. This small protein (6.5 kD) coimmunoprecipitates with the alpha and beta subunits and is closely associated with the ouabain binding site on the holoenzyme, but its function is unknown. We have investigated the expression of the gamma subunit in preimplantation mouse development, where Na+, K+-ATPase plays a critical role as the driving force for blastocoel formation (cavitation). Using reverse transcriptase-polymerase chain reaction, we demonstrated that the gamma subunit mRNA accumulates continuously from the eight-cell stage onward and that it cosediments with polyribosomes from its time of first appearance. Confocal immunofluorescence microscopy revealed that the gamma subunit itself accumulates and is localized at the blastomere surfaces up to the blastocyst stage. In contrast with the alpha and beta subunits, the gamma subunit is not concentrated in the basolateral surface of the polarized trophectoderm layer, but is strongly expressed at the apical surface as well. When embryos were treated with antisense oligodeoxynucleotide complementary to the gamma subunit mRNA, ouabain-sensitive K+ transport (as indicated by 86Rb+ uptake) was reduced and cavitation delayed. However, Na+, K+-ATPase enzymatic activity was unaffected as determined by a direct phosphorylation assay ("back door" phosphorylation) applied to plasma membrane preparations. These results indicate that the gamma subunit, although not an integral component of Na+,K+-ATPase, is an important determinant of active cation transport and that, as such, its embryonic expression is essential for blastocoel formation in the mouse.

Animals↗
PubMed1997

Panhandle polymerase chain reaction amplifies MLL genomic translocation breakpoint involving unknown partner gene.

We used a new approach called panhandle polymerase chain reaction (PCR) to clone an MLL genomic translocation breakpoint in a case of acute lymphoblastic leukemia of infancy in which karyotype analysis was technically unsuccessful and did not show the translocation partner. Panhandle PCR amplified known MLL sequence 5' of the breakpoint and 3' sequence from the unknown partner gene from a DNA template with an intrastrand loop schematically shaped like a pan with a handle. The 7-kb panhandle PCR product contained the translocation breakpoint in MLL intron 8. The partner DNA included unique nonrepetitive sequences, Alu and mammalian apparent LTR-retrotransposon (MaLR) repetitive sequences, and a region of homology to expressed sequence tags. MaLR sequences have not been found before near leukemia-associated translocation breakpoints. The nonrepetitive sequences were not homologous to known partner genes of MLL. Screening of somatic cell hybrid and radiation hybrid lines by PCR and fluorescence in situ hybridization analysis of normal metaphase chromosomes mapped the partner DNA to chromosome band 4q21. Reverse transcriptase-PCR identified an MLL-AF-4 chimeric mRNA, indicating that panhandle PCR identified a fusion of MLL with a previously uncharacterized AF-4 intronic sequence. Panhandle PCR facilitates cloning translocation breakpoints and identifying unknown partner genes.

Base Sequence↗
PubMed1997

Oligomerization of the EGF receptor transmembrane domain: a 2H NMR study in lipid bilayers.

During the course of a previous study by wideline 2H NMR, we noted spectral features suggesting the possibility of monitoring homodimer/oligomer interactions between transmembrane domains of the EGF receptor in lipid bilayers [Rigby, A. R., Shaw, G. S., Barber, K. R., & Grant, C. W. M. (1996) Biochemistry 35, 12591-12601]. In the present work this possibility was explored using the 34-residue peptide EGFRtm. The peptide sequence included the 23 amino acid hydrophobic stretch thought to span the membrane (Ile622-Met644 of the EGF receptor), plus the first 10 amino acids of the receptor's cytoplasmic domain (Arg645-Thr654). Selective deuteration was carried out at sites corresponding to Ala623, Met644, and Val650. Samples were studied from 12 to 65 degrees C by 2H NMR in fluid membranes having low peptide concentration (1 mol %) or high peptide concentration (6 mol %). Methyl groups proved to be technically particularly attractive probe locations. Reversible homodimer/oligomer interactions were detected in membranes of the common natural phospholipid 1-palmitoyl-2-oleoylphosphatidylcholine (POPC), without cholesterol. Effects on the EGF receptor transmembrane domain included alterations in peptide backbone motional order and/or conformation at the site of Ala623 within the membrane, and alterations in motional properties of the Val650 side chain in the cytoplasmic domain. There was little spectral evidence of stable oligomer formation except at the lowest temperature studied. Addition of 33% cholesterol to these membranes was accompanied by spectral changes consistent with the formation of more stable peptide oligomers, and by evidence that peptide-peptide interactions were sensed at all three probe locations. Peptide-peptide interactions remained easily reversible, particularly at higher temperatures. Freeze-fracture electron microscopy of the NMR samples demonstrated peptide-related intramembranous particles traversing the membranes. To our knowledge, this is the first electron microscopy description of receptor tyrosine kinases or their fragments in model membranes. In the presence of cholesterol, the peptide-related particles were generally larger, more sharply demarcated, and showed a tendency to cluster. These observations relate to models of receptor lateral association as an aspect of signal transduction, and to forces that may determine protein sorting and organization in cell membranes. We suggest that the cholesterol effects reflect a general phenomenon rather than one specific to the EGF receptor.

Dimerization↗
PubMed1997

Panhandle PCR strategy to amplify MLL genomic breakpoints in treatment-related leukemias.

Panhandle PCR amplifies genomic DNA with known 5' and unknown 3' sequences from a template with an intrastrand loop schematically shaped like a pan with a handle. We used panhandle PCR to clone MLL genomic breakpoints in two pediatric treatment-related leukemias. The karyotype in a case of treatment-related acute lymphoblastic leukemia showed the t(4;11)(q21;q23). Panhandle PCR amplified the translocation breakpoint at position 2158 in intron 6 in the 5' MLL breakpoint cluster region (bcr). The karyotype in a case of treatment-related acute myeloid leukemia was normal, but Southern blot analysis showed a single MLL gene rearrangement. Panhandle PCR amplified the breakpoint at position 1493 in MLL intron 6. Screening of somatic cell hybrid and radiation hybrid DNAs by PCR and reverse transcriptase-PCR analysis of the leukemic cells indicated that panhandle PCR identified a fusion of MLL intron 6 with a previously uncharacterized sequence in MLL intron 1, consistent with a partial duplication. In both cases, the breakpoints in the MLL bcr were in Alu repeats, and there were Alu repeats in proximity to the breakpoints in the partner DNAs, suggesting that Alu sequences were relevant to these rearrangements. This study shows that panhandle PCR is an effective method for cloning MLL genomic breakpoints in treatment-related leukemias. Analysis of additional pediatric cases will determine whether breakpoint distribution deviates from the predilection for 3' distribution in the bcr that has been found in adult cases.

Adult↗
PubMed1997

Globoside as a membrane receptor: a consideration of oligosaccharide communication with the hydrophobic domain.

Recognition of macromolecules by glycosphingolipids is closely correlated with the nature of the glycolipid carbohydrate; however, it is also thought to be secondarily modulated by the structure of the single fatty acid. In the present work, we sought insight into what physical effect a change in this fatty acid has on the extramembranous portion of globosides at liposomal surfaces mimicking systems for which modulated receptor function has been recorded in the past. Protons of the exocyclic hydroxymethyl group on the terminal Gal residue of globotriaosylceramide (Gb3) were replaced with deuterium. In this location, the nonperturbing probe nuclei sampled cumulative conformational and orientational characteristics of the oligosaccharide chain at a sugar residue that is critical in specific binding of verotoxins. Deuterated Gb3 having 18:1 fatty acid was compared to the same species having 22:1 fatty acid, at 6.3 mol % in unsonicated bilayers of dipalmitoylphosphatidylcholine/cholesterol. Both produced narrow, apparently axially asymmetric 2H NMR spectra over a wide temperature range. Motional properties of the terminal sugar were measurably influenced by the fluidity of the host matrix; however, evidence was not found for conformational or orientational variation in this sugar brought about by the fatty acid alteration. In related experiments, acetate protons on the terminal N-acetyl galactosamine (GalNAc) residue of globotetraosylceramide (Gb4) were substituted with deuterium, and the natural fatty acid was replaced with 18:0 or 24:0 species deuterated at C2. Once again, species with short vs long fatty acid were examined for evidence of headgroup differences. Spectra of Gb4 were compared at 10 mol % in unsonicated fluid bilayers of 1-palmitoyl-2-oleoylphosphatidylcholine, and at 5 mol % in membranes containing 33 mol% cholesterol. Spectral splittings reflecting cumulative effects on conformation and order at the terminal deuterated sugar remained unchanged between species having 18:0 vs 24:0 fatty acid in POPC/cholesterol. In a pure POPC host matrix, there was clear evidence of a motional difference between the two--the longer chain Gb4 demonstrating spectral asymmetry--but the spectral width was unchanged. Transverse relaxation times, T2, were measured. Our findings appear to help correlate the conclusions of a number of workers dealing with the molecular basis of crypticity. We suggest that changes in glycolipid receptor function based on ceramide fatty acid variation have a major origin in the fatty acid's ability to determine the thermodynamics of interaction with the host matrix, as reflected in such parameters as glycolipid motional properties, local membrane curvature, and likely glycolipid time-dependent lateral associations. The result at low concentrations of glycolipid may often be only a subtly altered collective surface epitope, best detected by a specific recognition event.

Carbohydrate Sequence↗
PubMed1997

Activity of L-phenylalanine ammonia-lyase in organic solvents.

L-Phenylalanine ammonia-lyase (EC 4.3.1.5), (PAL) was shown to be active in a monophasic non-aqueous medium for the first time. Ultraviolet absorbance spectra of trans-cinnamic acid were shown to be similar in both water and n-octanol. High catalytic rates were observed only when the enzyme was placed in solvents containing high concentrations of water. PAL forward reaction was observed only when the water concentration in n-octanol exceeded 2.0% (v/v), which corresponds to a value of 0.8 in thermodynamic water activity (aw) terms. In n-octanol containing either 2.0 or 3.5% (v/v) H2O (and 2 mM L-phenylalanine), lyophilized and aw = 0.113 pre-equilibrated PAL powder exhibited catalytic rates 0.02 and 1.75% of the value observed in aqueous solution respectively. A freshly lyophilized (non-equilibrated) PAL preparation incubated in water-saturated n-octanol (measured [H2O] = 3.6% (v/v), L-phenylalanine concentration approximately 6.8 mM) gave catalytic activity values 17% of those observed in aqueous solution. This is the first demonstration of catalytic activity of an amino acid ammonia-lyase in monophasic organic solvent.

1-Octanol↗
PubMed1997

Pilin C-terminal peptide binds asialo-GM1 in liposomes: a 2H-NMR study.

Wideline 2H-NMR observations are described demonstrating the interaction of a synthetic peptide (PAK), representing residues 128-144 of the binding domain of pilin surface protein from Pseudomonas aeruginosa, with a complex glycosphingolipid thought to be its natural receptor. The receptor glycolipid (asialo-GM1) carried 2H probe nuclei on the terminal and next-to-terminal carbohydrate residues and was present as a minor component in fluid phosphatidylcholine liposomes. The peptide induced spectral changes that could be understood as arising from receptor motional changes, without receptor immobilization on the NMR time scale of 10(4) s-1. Spectral effects were reversed by reduction of the single peptide disulfide bond--a structural feature previously shown to be a determinant of PAK conformation (Campbell AP, McInnes C, Hodges RS, Sykes BD. 1995. Biochemistry 34:16255-16268). This is the first demonstration of PAK interaction with its epithelial cell receptor in liposomes.

Amino Acid Sequence↗
PubMed1997

Poly(DL-lactide-co-glycolide)-encapsulated plasmid DNA elicits systemic and mucosal antibody responses to encoded protein after oral administration.

We have developed a method for the encapsulation of plasmid DNA in poly(DL-lactide-co-glycolide) microparticles. Encapsulated DNA, expressing the insect protein luciferase under the transcriptional control of the human cytomegalovirus immediate early promoter, was administered to mice by intraperitoneal injection or oral gavage. Intraperitoneal injection of encapsulated DNA elicited good serum IgG and IgM responses, and a modest IgA response. Oral administration stimulated good serum antibody responses in all three classes, and in addition, significant levels of mucosal IgA. PLG encapsulation thus has the ability to protect plasmid DNA against degradation after administration, and to facilitate its uptake into appropriate cells for the subsequent expression and presentation of antigen, in such a way as to elicit both systemic and mucosal antibody responses. These findings may have major implications for the design of novel vaccines and delivery strategies.

Administration, Oral↗
PubMed1997

Socioeconomic and racial/ethnic factors affecting non-fatal medically attended injury rates in US children.

OBJECTIVE: Using a representative survey of US children, the purpose was to evaluate separate effects of socioeconomic and racial/ethnic factors, including access to care, on medically attended non-fatal injury rates. METHODS: Multivariate linear regression models were used to determine associations between injuries and health care coverage (insurance or Medicaid), having a place to go for care, race/ethnicity, maternal education, number of adults and children in the household, poverty, and urbanicity. The 1988 Child Health Supplement to the National Health Interview Survey included questions on medically attended injuries, and their cause, location, and effects on the child. Injury categories included total, consequential, occurrence at home or school, falls, and being struck or cut. RESULTS: Lack of health care coverage was consistently associated with lower medically attended injury rates in non-Hispanic blacks or whites and Mexican-Americans, but affected total rates for each group differently due to unequal distribution of health care coverage. Injuries occurred about 40% more frequently to children and adolescents living in single adult households compared with two adult homes for all injury categories except for injuries occurring at school. CONCLUSIONS: Preventive interventions targeted to specific populations based on assumptions that poverty, lack of education, or minority status result in greater risks for injuries require a closer look. Efficient targeting should address underlying factors such as differences in exposures and environments associated with single adult homes or recreational activities. Data sources used to target high risk populations for interventions need to address bias due to access to care.

Adult↗
PubMed1997

Carpal tunnel syndrome in the mucopolysaccharidoses and mucolipidoses.

Children with a mucopolysaccharidosis or mucolipidosis suffer progressive disability of the hands, particularly in relation to dysfunction of the median nerve. This is an increasing problem because bone-marrow transplantation has dramatically improved survival without apparently changing the musculoskeletal manifestations. We have reviewed 48 children with these syndromes who required carpal tunnel decompression, recording symptoms, signs, radiological, electrophysiological and operative findings, histology and upper-limb function. In these children the carpal tunnel syndrome differs from that seen in adults. Symptoms are rare but signs such as decreased sweating, pulp atrophy, thenar wasting and manual clumsiness are much more common. At operation, the flexor retinaculum was thickened and a mass of white tenosynovium engulfed the flexor tendons. Most patients had some definite nerve constriction with a thickened epineurium. Functional improvement was seen after early decompression, with some benefit from simultaneous tendon release. Regular physiotherapy helped to maintain increased hand movement. We describe our assessment protocol, the physiotherapy and operative regime and the standard functional review which helps to maximise function in the hands and upper limbs of these children.

Adolescent↗
PubMed1997

Epitope mapping and tagging by recombination PCR mutagenesis.

We describe a rapid PCR method that directly inserts an epitope tag into an open reading frame (ORF) to facilitate protein detection. This project was performed within a varicella-zoster virus (VZV) system. In earlier work, we produced a monoclonal antibody (MAb 3B3) to one VZV ORF called gE. MAb 3B3 bound to its epitope under extreme denaturing conditions. To further characterize the epitope, we devised a technique that identified the epitope by its insertion into another protein of interest. The 3B3 epitope was mapped to 11 residues (residues 151-161; QRQYGDVFKGD) in the gE ectodomain by using the technique of recombination PCR. At the same time, the 3B3 epitope was inserted in-frame into another VZV protein for which no MAb was available. The end result, VZV gL3B3.11, was a unique construct possessing a 33-bp insertion that expresses gL-3B3 protein recognized by the MAb 3B3. The 3B3 epitope was verified to be both highly functional and stable. An important advantage of this recombination PCR method of epitope mapping and tagging is that the epitope sequence can be inserted anywhere along the nucleotide sequence of an ORF, regardless of existing restriction sites.

Amino Acid Sequence↗
PubMed1997

An iterative and regenerative method for DNA sequencing.

This paper presents, to our knowledge, the first iterative DNA sequencing method that regenerates the product of interest during each iterative cycle, allowing it to overcome the critical obstacles that impede alternative iterative approaches to DNA sequencing: loss of product and the accumulation of background signal due to incomplete reactions. It can sequence numerous double-stranded (ds) DNA segments in parallel without gel resolution of DNA fragments and can sequence DNA that is almost entirely double-stranded, preventing the secondary structures that impede sequencing by hybridization. This method uses ligation of an adaptor containing the recognition domain for a class-IIS restriction endonuclease and digestion with a class-IIS restriction endonuclease that recognizes the adaptor's recognition domain. This generates a set of DNA templates that are each composed of a short overhang positioned at a fixed interval with respect to one end of the original dsDNA fragment. Adaptor ligation also appends a unique sequence during each iterative cycle, so that the polymerase chain reaction can be used to regenerate the desired template-precursor before class-IIS restriction endonuclease digestion. Following class-IIS restriction endonuclease digestion, sequencing of a nucleotide in each overhang occurs by template-directed ligation during adaptor ligation or through a separate template-directed polymerization step with labeled ddNTPs. DNA sequencing occurs in strides determined by the number of nucleotides separating the recognition and cleavage domains for the class-IIS restriction endonuclease encoded in the ligated adaptor, maximizing the span of DNA sequenced for a given number of iterative cycles. This method allows the concurrent sequencing of numerous dsDNA segments in a microplate format, and in the future it can be adapted to biochip format.

Base Sequence↗
PubMed1997

Amplification of 4-9-kb human genomic DNA flanking a known site using a panhandle PCR variant.

We present a method for the in vitro amplification of > 6.0 kb of DNA flanking a known site. This is accomplished by ligating an oligonucleotide to create an inverted repeat of a portion of the known sequence, followed by single-primer polymerase chain reaction (PCR) amplifications. This method generates a panhandle template following primer extension on the strand of interest. It does not involve template-directed extension from the ligated oligonucleotide, and it is carried out without DNA extractions. We have used this method to amplify 4.5-9.4 kb of DNA flanking the original primer annealing sites directly from human genomic DNA.

Base Sequence↗