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Biomedical subjects

B Gunning

Publications and source records attributed to B Gunning.

11 recordsLinked to original sources
PubMed2000

Memory disturbances in "Ecstasy" users are correlated with an altered brain serotonin neurotransmission.

RATIONALE: Methylenedioxymethamphetamine (MDMA) is known to damage brain pre-synaptic serotonin (5-HT) neurons. Since loss of 5-HT neurons has been implicated in memory loss, it is important to establish whether MDMA use may produce changes in postsynaptic 5-HT receptors and memory function in humans. OBJECTIVES: To investigate whether MDMA use leads to compensative alterations in post-synaptic 5-HT2A receptors and whether there is a relation with memory disturbances. METHODS: Brain cortical 5-HT2A receptor densities were studied with [123I]-5-I-R91150 SPECT in five abstinent MDMA users and nine healthy controls. Memory performance was assessed using RAVLT. RESULTS: [123I]-5-I-R91150 binding ratios were significantly higher in the occipital cortex of MDMA users than in controls, indicating up-regulation. Mean cortical 5-HT2A receptor binding correlated positively with RAVLT-recall in MDMA users. CONCLUSION: Our preliminary results may indicate altered 5-HT neuronal function with correlated memory impairment in abstinent MDMA users.

Adult↗
PubMed1999

The effect of methylphenidate and clonidine on response inhibition and state regulation in children with ADHD.

The goal of this study was to evaluate the effect of methylphenidate (MPH) and clonidine in comparison with placebo on response inhibition and state regulation in children with Attention Deficit Hyperactivity Disorder (ADHD). The study utilised a double-blind cross-over design in which children were randomly assigned without replacement to placebo, MPH, and clonidine following baseline assessment. The primary dependent measures were derived from children's performance (reaction time and errors) on a GO-NO GO task under three conditions that altered the inter-stimulus interval (ISI) for presented GO-NO GO stimuli: ISI of 1 sec (fast condition), 4 sec (medium condition), and 8 sec (slow condition). Findings indicated no difference in task performance between groups treated for 7 weeks with placebo, MPH, and clonidine. We concluded that the state regulation problem in ADHD is resistant to MPH and clonidine.

Arousal↗
PubMed1985

Some biochemical properties of higher plant tubulins.

Tubulin was isolated by a combination of affinity (ethyl N-phenylcarbamate-Sepharose) and ion exchange (DEAE-Sephacel) chromatography from mung bean and cultured carrot suspension cells. SDS-PAGE (Blose 1981) of mung bean tubulin has shown it to consist of two major subunits (MBT1 and MBT2) and a minor subunit (MBT3). Tubulin isolated from carrot cells was resolved into only two bands on SDS-PAGE (slow moving subunit was named CT1). However, the faster moving subunit on SDS-PAGE was resolved into two bands (CT2 and CT3) on SDS-4M urea-PAGE. On SDS-4M urea-PAGE, CT1 migrated faster than CT2, CT3. By contrast in SDS-4M urea-PAGE, mung bean tubulin remains unresolved. Mammalian tubulin could be resolved into alpha and beta-subunits in both electrophoretic systems. Monoclonal antibodies to mammalian alpha and beta-tubulin subunits (MCA-T alpha and MCA-T beta, respectively) and Western blot analysis clearly demonstrated a cross-reactivity of MCA-T alpha with MBT2, MBT3, CT2 and CT3, while MCA-T beta showed cross-reactivity with MBT1 and CT1. Although MBT2, MBT3, CT2 and CT3 are immunologically related to the alpha-subunit of mammalian tubulin, their migration on SDS-PAGE was reversed with respect to MBT1 or CT1, which were immunologically related to the beta-subunit of mammalian tubulin. Peptide mapping patterns also supported above the results.

Antibodies, Monoclonal↗
PubMed1980

Observations on pre-prophase bands of microtubules in uniseriate hairs, stomatal complexes of sugar cane, and Cyperus root meristems.

Three aspects of the location and properties of pre-prophase bands of microtubules inplant tissues were examined. (i) Anatomical locations: Pre-prophase bands were found preceding mitosis in the basal meristematic cell of uniseriate hairs in Salvinia auriculata and in intercalary dividing cells in the uniseriate hairs of Tradescantia stamens. Previously they had only been found in 2- or 3-dimensional aggregates of cells. Other new locations were Tradescantia stamen filaments, and periclinal and anticlinal divisions in root and root cap meristems of Cuperus eragrostis. (ii) Prediction of the site of cytokinesis: Developing stomatal complexes of Saccharum officinarum were examined in view of recent reports that guard mother cells in this plant violate the otherwise general rule that the pre-prophase band predicts the line of fusion of the cell plate and the parental wall. The generality of the prediction phenomenon was upheld. (iii) Bisection of pre-prophase band sites: Evidence that the site of the pre-prophase band in the cell cortex is (at least approximately) bisected at cytokinesis was obtained for asymmetrical divisions in Cyperus roots, stomatal complexes of Saccharum, and Salvinia hairs, and symmetrical divisions in Tradescantia stamen hairs and Saccharum guard mother cells. The observations are discussed with particular reference to possible roles of the pre-prophase band site after its microtubules have disappeared at prophase.

Cell Cycle↗