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Biomedical subjects

C J Jones

Publications and source records attributed to C J Jones.

At least 109 records · Page 6Linked to original sources
PubMed1995

Changes in glycan distribution within the porcine interhaemal barrier during gestation.

Changing patterns of glycan distribution are described in porcine placentae at 15, 19, 26, 43, 58, 69 and 109 days gestation, using a carefully selected panel of lectins that allowed partial analysis of saccharide classes and sequences. The lectins used were from Galanthus nivalis, Pisum sativum, Phaseolus vulgaris (leukohaemagglutinin), Triticum vulgaris, Tetragonolobus purpureus, Ulex europaeus-1, Arachis hypogaea, Erythrina cristagalli, Glycine max, Maclura pomifera, Wisteria floribunda, Dolichos biflorus, Maackia amurensis, Sambucus nigra and Limax flavus. During the course of gestation the trophoblast developed from a smooth to a deeply folded membrane, while enlarging fetal and maternal capillaries grew closer to each other. The fetomaternal interface expressed many classes of saccharide, both O- and N-linked, but failed to bind DBA, MAA and SNA. Many granules were present in the maternal epithelium, and a striking feature was the appearance of staining with DBA and UEA-1 by day 43. This stage of pregnancy was also associated with changes in trophoblast glycan expression, with a diminution in staining intensity of AHA, MPA and LTA, but an increased intensity with ECA, SBA and WFA. Changes in lectin binding throughout gestation are correlated with previous ultrastructural findings and their relevance to the immunological and functional aspects of pregnancy is discussed.

Animals↗
PubMed1995

Real-time measurement of pulse wave velocity from arterial pressure waveforms.

Instrumentation for the real-time clinical measurement of pulse wave velocity (PWV) from intra-arterial pressure waveforms is presented. This time delay between pressure waveforms (obtained from two intra- arterial catheter-mounted transducers 5 cm apart) is calculated by a transputer using multiple comparisons between discrete sections of the waveforms. The method is validated by analysis of digital and analogue signals with known time delays and is used to measure changes in PWV in the right common iliac artery (RCIA) during infusions of acetylcholine (2.4, 24 and 240 micrograms ml-1) in six healthy subjects. The system measures the delay between digitally shifted triangular waveforms and pressure waveforms to a precision of about 50 microseconds, and it is superior to measurements performed by hand using a high-performance digital storage oscilloscope. When used to measure the effects of acetylcholine on the RCIA, dose-dependent reductions in PWV are recorded (-85%, -11.6%, -14.5%). It is concluded that the instrumentation enables PWV to be measured with high accuracy and precision in real time, if the pressure signals are of high fidelity and the relative amplification of the signals is carefully balanced.

Algorithms↗
PubMed1995

Trophoblast differentiation during formation of anchoring villi in a model of the early human placenta in vitro.

In human implantation sites, formation of the cytotrophoblast shell and morphogenesis of anchoring villi occur during the 2nd and 3rd week of pregnancy. When placental villous tissue from 8-12 weeks was co-cultured with decidua parietalis, morphogenetic changes were observed specifically at sites of heterotypic contact, generating structures that closely resembled first trimester anchoring villi. Local breakdown of the syncytium and cytotrophoblast proliferation occurred, producing columns of cytotrophoblast. These columns showed complex changes of cell surface phenotype that replicate precisely the extravillous trophoblast differentiation pathway seen in vivo, including induction of integrin alpha 5 beta 1, loss of integrin alpha 6 beta 4 and expression of the HLA class I framework epitope recognized by monoclonal antibody W6/32. Extracellular matrix components including laminin, collagen type IV, fibrin and fibronectin were detected in intercytotrophoblastic spaces in the nascent columns. Spreading over the surface of the decidua and infiltration by cytotrophoblast were observed. We conclude that: (i) fist trimester floating villi retain the capacity to differentiate into anchoring villi; (ii) contact with decidua stimulates local breakthrough of the syncytium and cytotrophoblast proliferation; (iii) the resulting cytotrophoblast columns show phenotypic changes characteristic of these structures in vivo; and (iv) parietal decidua is capable of supporting implantation site-specific changes in a manner similar to the basal decidua.

Antigens, Surface↗
PubMed1995

Ultrastructure of the materno-embryonic interface in the first trimester of pregnancy.

During early pregnancy, the absence of fully developed internal organs means that the embryo is dependent on highly differentiated adnexal structures such as the secondary yolk sac and free-floating amniotic membrane as well as the placental trophoblast. In this review, we describe and illustrate the ultrastructural characteristics of these different cellular barriers which separate maternal and embryonic tissues during the first trimester of pregnancy. Samples of chorionic plate, umbilical cord, secondary yolk sac and amniotic membrane have been obtained from intact gestational sacs of pregnancies between 6 and 11 weeks and examined at the ultrastructural level. Features indicating intense biosynthetic activity were found in the syncytiotrophoblast of the chorionic plate, the endoderm of the secondary yolk sac and mesenchymal cells of the amniotic membrane. Barriers in the form of a well-developed basal lamina were present between the trophoblast and mesenchyme of the chorionic plate and beneath the epithelium of the amniotic membrane and umbilical cord, but were incomplete between the mesenchymal tissues of the yolk sac and mesothelial and endodermal layers, and also around the capillaries of the chorionic plate. Basement membrane thickening and interactions with the underlying stroma were observed with increasing gestational age in connection with amniotic epithelial differentiation and development of basal foot processes. After 9 weeks, the yolk sac showed a marked degeneration of surface cells, accompanied by increased fibrosis of the mesenchyme. These findings are discussed with reference to the biological functions of the adnexal structures in the development of the growing embryo, and their possible role is assessed in the physiology of exchange during the first trimester of pregnancy.

Amnion↗
PubMed1995

The physiological load imposed on basketball players during competition.

In this study, the intensities of activity and movement patterns during men's basketball were investigated by videoing the movements and monitoring the heart rate and blood lactate responses of eight elite players during competition. The results are expressed according to 'live time', which is actual playing time, and 'total time', which includes live time as well as all stoppages in play. The mean (+/- S.D.) frequency of all activities was 997 +/- 183, with a change in movement category every 2.0 s. A mean total of 105 +/- 52 high-intensity runs (mean duration 1.7 s) was recorded for each game, resulting in one high-intensity run every 21 s during live time. Sixty percent of live time was spent engaged in low-intensity activity, while 15% was spent in high-intensity activity. The mean heart rate (HR) during live time was 169 +/- 9 beats min-1 (89 +/- 2% peak HR attained during laboratory testing); 75% of live time was spent with a HR response of greater than 85% peak HR. The mean blood lactate concentration was 6.8 +/- 2.8 mM, indicating the involvement of glycolysis in the energy demands of basketball. It is concluded that the physiological requirements of men's basketball are high, placing considerable demands on the cardiovascular and metabolic capacities of players.

Adolescent↗
PubMed1995

Marfan syndrome: fibrillin expression and microfibrillar abnormalities in a family with predominant ocular defects.

We have found abnormal fibrillin microfibrils isolated from tissues and cell cultures from two cousins with Marfan syndrome whose major clinical abnormality is bilateral ectopia lentis, but who also have skeletal involvement but no cardiovascular defects. Ultrastructural analysis of ciliary zonules showed the presence of abundant loose microfibril bundles which in many places appeared disorganised. Microfibrils isolated from ciliary zonules and vitreous were highly fragmented when examined by rotary shadowing electron microscopy. Investigation of microfibrils elaborated by patient dermal fibroblasts showed remarkable variations in periodicity and packing. The synthesis and secretion of fibrillin by these cells was confirmed electrophoretically with the identification of metabolically labelled immunoprecipitated fibrillin (M(r) 300,000) in medium and cell layer compartments. These data show that fibrillin expression is normal but that assembled microfibrils are manifestly abnormal both morphologically and functionally. The occurrence of microfibrils with variable periodicities and susceptibility to fragmentation suggests that structural weakness is probably the primary cause of lens dislocation in these patients.

Actin Cytoskeleton↗
PubMed1995

Studies of hemidesmosomes in human amnion: the use of a detergent extraction protocol for compositional and ultrastructural analysis and preparation of a hemidesmosome-enriched fraction from tissue.

A method is described for the sequential detergent and high ionic strength extraction of human amnion with the progressive enrichment of the intermediate filament (IF) cytoskeleton and its associated structures including hemidesmosomes (HD). TEM of the extracted epithelium in situ reveals IF bundles beneath the apical cell surface, around the nucleus and at the lateral edges of the cells where association with desmosomes occurs. IF bundles are also very prominent within basal cell processes where they loop through the cytoplasm adjacent to the HDs. A novel connecting filament network is observed running between the IFs and the hemidesmosomal dense plaque. The adjacent IF network contains both cytokeratin and vimentin, the latter revealed much more fully as a result of the extraction protocol. The hemidesmosomal plasma membrane contains integrin subunits alpha 6 and beta 4 and these are quantitatively retained as the basal cell surface during extraction, while nonjunctional plasma membrane is solubilised. Integrin beta 1 is found at the basolateral cell surface but, like actin, is extracted quantitatively and is not present in HDs. The extracted epithelial cells may be recovered by scraping and the IF network depolymerised to produce a particulate fraction containing short residual IFs, associated thin filaments and plaque material. This fraction contains immunoreactive cytokeratin and vimentin. Integrin alpha 6 beta 4 has been used as a biochemical criterion of the presence of HD material in the fraction. Both subunits are highly enriched. The fraction also contains the hemidesmosomal components HD1, BP230 and BP180. This method is likely to be useful in further characterisation of the HD.

Actins↗
PubMed1995

The convergence of the California Q-set and the California Psychological Inventory: gender as a critical variable.

Clinician-report California Q-set and self-report California Psychological Inventory data were compared to explore convergence and divergence between these two modes of personality assessment. Based on responses from a sample of 215 approximately 50-year-old men and women, the self-report California Psychological Inventory data were converted to California Q-set item values using previously determined redundancy analysis formulae. These data were then correlated with composite clinicians' ratings, using the same California Q-set items. Substantial convergence was found for both genders on four of six derived components--Empowerment, Intellectuality, Nonconformity, and Outgoingness. Two additional components--Psychological Health and Bodily Concern--showed convergence for women only. We argue analysis of item content and scores must be done for each gender separately.

Adult↗
PubMed1995

Glycans of the early human yolk sac.

The pattern of glycan distribution in the early human yolk sac has been investigated using a panel of lectins. Two 6-week and one 8-week human yolk sacs, and one 8-week fetal liver from live, ectopic pregnancies were fixed and embedded in epoxy resin. Lectin histochemistry was carried out on sections of these tissues using 23 biotinylated lectins and an avidin-biotin peroxidase revealing system. Mesothelial surfaces expressed most subsets of N-glycans (other than high mannose types), N-acetyl-lactosamine, sialic acid, and alpha 1,6-N-acetylgalactosamine. Endodermal surface and lateral membranes resembled those of mesothelium, but showed a preponderance of alpha 2,6-sialyl residues. Most intracellular granules contained N-glycan. There was a marked heterogeneity of granules in the endodermal cells, with different subsets varying in both staining and positional characteristics. The mesenchymal matrix bound most of the lectins used in the study, and expressed fucosyl residues which were also detected in the endothelium. Fetal liver parenchyma showed very similar staining patterns to those seen in the endoderm except for the distribution of N-acetylglucosamine, which was sparse. Despite some common features, each germ cell layer had a distinct 'glycotype', with some saccharides showing extreme topographical restriction.

Biotin↗
PubMed1995

Glycoconjugates of the human trabecular meshwork: a lectin histochemical study.

Twelve specimens of resin-embedded human trabecular meshwork were probed with a panel of 21 biotinylated lectins, using an avidin-biotin peroxidase revealing system, in order to determine the normal pattern of saccharide expression in this tissue. High-mannose, intermediate and hybrid N-linked glycans, and complex N-linked bisected and non-bisected bi/tri-antennate glycans, as shown by the binding of Canavalia ensiformis (ConA), Pisum sativum (PSA), Lens culinaris (LCA) agglutinins and Phaseolus vulgaris erythroagglutinin (ePHA), were strongly expressed by the canal of Schlemm endothelium and juxtacanalicular tissue, but less so by the corneoscleal meshwork. Highly branced complex glycans were not found, as there was no binding by Phaseolus vulgaris leukoagglutinin (IPHA). Sialyl residues, especially those alpha 2,6-linked as demonstrated by strong Sambucus nigra (SNA) lectin staining, were also abundant in this area. N-acetyllactosamine sequences and some O-linked glycans were present in the trabecular meshwork, as shown by Solanum tuberosum (STA), Datura stramonium (DSA), and Jacalin (Jac) lectin binding, while fucose residues were not detected by Tetragonolobus purpureas (LTA) or Ulex europaeus-1 (UEA-1) agglutinins. These results indicate similarities with renal glomerular and vascular endothelium, although the lack of binding with UEA-1 agglutinin suggests differences which may relate to the specialized function of the trabecular meshwork. This study provides a baseline for comparative analysis of the glycans of human trabecular meshwork in pathological conditions such as primary open-angle glaucoma.

Adult↗
PubMed1994

Human urokinase receptor expression is inhibited by amiloride and induced by tumor necrosis factor and phorbol ester in colon cancer cells.

The modulation of urokinase plasminogen activator receptor (uPAR) gene expression by tumor necrosis factor alpha (TNF alpha), phorbol ester (PMA) and amiloride was studied in three colon cancer cell lines. uPAR mRNA and protein were induced by TNF alpha and by PMA but were inhibited by amiloride at concentrations of 0.1 to 1 mM in the presence or absence of TNF alpha and PMA. Nuclear run-on transcription assay indicated that the effects of amiloride and TNF alpha were mediated at least in part at the transcriptional level, whereas PMA may act in part via a posttranscriptional mechanism. These results suggested that uPAR gene expression is modulated by multiple signal transduction pathways.

Amiloride↗
PubMed1994

Lectin-histochemical analysis of glycans in ovine and bovine near-term placental binucleate cells.

Chorionic binucleate cells (BNC) occur in several ruminants including cow, deer, goat and sheep. They migrate through the chorionic tight junction to fuse with uterine epithelial cells and discharge their granules into maternal connective tissue. We have compared the BNC of near-term, resin-embedded, ovine and bovine placentae using 15 biotinylated lectins and an avidinperoxidase revealing system. There was pronounced conservation of saccharides between the two species. Several sub-types of N-glycan were present, with highly branched structures being abundant, as shown by Galanthus nivalis, Pisum sativum and Phaseolus vulgaris (leuko) agglutinins. Among the non-reducing terminal saccharides conserved were GalNAc alpha 1,3(Fuc alpha 1,2)-Gal beta 1,4GlcNAc beta 1-, GalNAc alpha 1,6Gal beta 1-, Gal beta 1-, Gal beta 1,4GlcNAc- and Gal beta 1,3GalNAc alpha 1- shown by Dolichos biflorus, Wisteria floribunda, Erythrina cristagalli, and Maclura pomifera agglutinins, respectively. Arachis hypogaea and Glycine max agglutinins tended to bind to bovine BNC at different stages of maturity, while fucosyl residues detectable by Tetragonolobus purpureus and Ulex europaeus-1 agglutinins were not observed in either species. The only major difference related to sialyl residues, with alpha 2,3-linked sialic acid being present in bovine (Maackia amurensis, Limax flavus) and alpha 2,6 sialic acid being present in ovine (Sambucus nigra agglutinin) cells. This conservation of glycan may be related to glycosylation of peptide hormones in the granules, and may thus be important in the targeting of these hormones to their receptors.

Animals↗
PubMed1994

Na+ transport, H+ concentration gradient dissipation, and system A amino acid transporter activity in purified microvillous plasma membrane isolated from first-trimester human placenta: comparison with the term microvillous membrane.

Our purpose was to isolate microvillous plasma membrane from first-trimester placenta and to measure its transport properties with regard to Na+, H+, and a neutral amino acid. Microvillous membrane was isolated from first-trimester (10 to 13 weeks) and term (38 to 42 weeks) placenta and the purity determined. Uptake of 22Na+ was measured in the presence of an outwardly directly H+ gradient in the presence or absence of amiloride (0.5 mmol/L). The rate of dissipation of an H+ concentration gradient was determined with the H(+)-sensitive fluorescent probe 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein. 14C-methylaminoisobutyric acid uptake was measured in the presence and absence of an inwardly directed Na+ gradient. Purity, vesicle volume, vesicle orientation, and electron micrographic appearance of the first-trimester membranes were similar to those obtained from term placenta, but vesicle protein recovery was lower. Amiloride-sensitive Na+ uptake and Na(+)-dependent 14C-methylaminoisobutyric acid uptake was threefold to fourfold lower by first-trimester than by term membranes. The rate of H+ concentration gradient dissipation was greater in the former. The first-trimester microvillous membrane has similar general characteristics to that from term placenta, but its transport activity is quite different.

Amino Acid Transport Systems↗
PubMed1994

Analysis of cells harboring a putative DNA repair gene reveals a lack of evidence for a second independent xeroderma pigmentosum group A correcting gene.

The UV hypersensitivity of xeroderma pigmentosum (XP) complementation group A cells is restored to near-normal by transfection of the XPA gene located on human chromosome 9. However, it has been reported that a cosmid related to a cDNA on chromosome 8 is also able to partially correct the UV sensitivity of XP-A cells. We describe here an investigation of a representative cosmid transfectant, denoted 2-0-A2. Whole cell extracts prepared from 2-0-A2 cells carried out DNA repair synthesis in vitro that was in the normal range, consistent with their UV-resistant phenotype. Immunoblotting indicated that 2-0-A2 cells expressed full-length XPA protein. This was unexpected because the 2-0-A2 cell line was thought to have been isolated by transfection of a cell line derived from patient XP2OS, and a known homozygous mutation in XP2OS prevents expression of XPA gene product. This mutation creates an AlwNI restriction endonuclease cleavage site in XPA and was not present in 2-0-A2. These results prompted an RFLP analysis which revealed that the 2-0-A2 cell line was not derived from XP2OS but from another line that fails to express XPA protein, XP12BE. It appears that the significant UV-resistance and DNA repair capacity of 2-0-A2 can be ascribed to the re-expression of XPA in XP12BE, and it is unnecessary to postulate a second XP-A complementing gene to explain the results.

Base Sequence↗
PubMed1994

Non-invasive measurement of pulse wave velocity using transputer-based analysis of Doppler flow audio signals.

A system for the measurement of arterial pulse wave velocity is described. A personal computer (PC) plug-in transputer board is used to process the audio signals from two pocket Doppler ultrasound units. The transputer is used to provide a set of bandpass digital filters on two channels. The times of excursion of power through thresholds in each filter are recorded and used to estimate the onset of systolic flow. The system does not require an additional spectrum analyser and can work in real time. The transputer architecture provides for easy integration into any wider physiological measurement system.

Arteries↗
PubMed1994

Addition of morphine to intra-articular bupivacaine does not improve analgesia after day-case arthroscopy.

We conducted a randomized, double-blind, controlled study in patients undergoing day-case knee arthroscopy to evaluate the analgesic effect, for 36 h after operation, of the addition of either 2 mg or 5 mg of morphine to intra-articular bupivacaine. Patients in group BM5 (n = 20) received 0.25% bupivacaine 40 ml with morphine 5 mg; patients in group BM2 (n = 20) received 0.25% bupivacaine 40 ml with morphine 2 mg and patients in group B0 (n = 18) received 0.25% bupivacaine 40 ml only. The drugs were given by intra-articular injection by the surgeon at the end of the operation and the tourniquet released 10 min later. Preoperative and postoperative pain was assessed over the ensuing 36 h, at rest and with movement, using a 100-mm visual analogue scale. There were no significant differences in pain scores, consumption of additional analgesia, or time to first request for analgesia between any of the groups. We conclude that, after day-case knee arthroscopy, no additional analgesic effect was afforded by the addition of morphine to intra-articular bupivacaine.

Adolescent↗