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D Chong

Publications and source records attributed to D Chong.

7 recordsLinked to original sources
PubMed1995

The relationship between glycine and gephyrin in synapses of the rat spinal cord.

In order to examine the relationship between gephyrin (the peripheral membrane protein associated with glycine receptors) and glycinergic boutons, we have carried out a post-embedding immunogold study of glycine-like immunoreactivity on sections of rat lumbar spinal cord which had previously been reacted with monoclonal antibody to gephyrin. In all three areas examined (laminae I and II, lamina III and lamina IX) the majority of profiles which were presynaptic at gephyrin-immunoreactive synapses were enriched with glycine-like immunoreactivity. It was estimated that at least 83% of profiles presynaptic to gephyrin-immunoreactive synapses in the superficial dorsal horn (laminae I and II) were glycine-immunoreactive, while for lamina III and the ventral horn (lamina IX) the proportions were at least 91% and 98% respectively. This provides strong evidence that glycine is a transmitter at those synapses where gephyrin- and glycine-like immunoreactivities are both present, but suggests that gephyrin may sometimes be expressed at non-glycinergic synapses and indicates the need for caution in using gephyrin-immunoreactivity as a marker for glycinergic synapses within the spinal cord. By reacting serial sections of dorsal horn with antisera to glycine and GABA, we have shown that many boutons in laminae I-III of the dorsal horn show both types of immunoreactivity and are therefore likely to use both amino acids as inhibitory transmitters. Many of the boutons which were presynaptic at axoaxonic synapses in the ventral part of lamina II and in lamina III were glycine- and GABA-immunoreactive and in many cases the postsynaptic element was the central axon of a type II synaptic glomerulus. Taken together with pharmacological evidence, this suggests that inhibitory interneurons in the dorsal horn which use both GABA and glycine may be important in controlling the flow of information from hair follicle afferents to other spinal neurons.

Afferent Pathways↗
PubMed1994

Serum potassium concentrations in trauma patients.

Hypokalemia occurs in 50% to 68% of trauma patients. To investigate the pathophysiology of these changes in serum potassium, we prospectively studied 133 trauma patients. Among the patients who had hypokalemia, the serum potassium usually decreased within 1 hour of trauma and returned to normal within 24 hours without significant potassium replacement. In bivariant analysis, age, admission systolic blood pressure, cardiac injury, and serum epinephrine level were associated with admission serum potassium value (K1), whereas sex, mechanism of injury, number of organ systems injured, blood glucose, serum alcohol, arterial pH, Injury Severity Score, trauma score, estimated blood loss, and urine potassium were not significantly related to K1. But in a multiple regression model, the only significant independent variables were age, arterial pH, and serum epinephrine level.

Adult↗
PubMed1989

Polycarbonate membranes: a novel surface for solid-phase determinations with utility in field format serological assays.

A dipstick suitable for immunoassay procedures has been developed, and its utility demonstrated by the development of tests for the determination of immunoglobulin levels in newborn bovine blood, and for the detection of bovine antibodies against Brucella abortus. The dipstick is of simple design, consisting of three components: a polycarbonate membrane, an adhesive, and a support material. The polycarbonate membrane is a porous filter material upon which the immunoassay is undertaken. Biomolecules bind to the membrane with sufficient affinity to permit the development of useful immunoassay procedures; however, this membrane exhibits low non-specific binding of reagents. Collectively, these properties make polycarbonate a useful material for solid-phase immunoassay procedures.

Animals↗
PubMedDate not supplied

Attentional processing in hyperthyroid children before and after treatment.

To determine whether specific components of attentional processing may be differentially disrupted during thyrotoxicosis, nine children with hyperthyroidism were assessed for intelligence and attention before and after one year of therapy. The attention test allowed for measurement of sustain, disengage, and shift subcomponents of attentional processing. Comparison with pediatric controls revealed lower nonverbal intelligence during thyrotoxicosis, which improved to normal following euthyroidism. On the attention task, an effect was observed during thyrotoxicosis only on the shift and disengage functions of attentional processing but not sustain. Attention results were unrelated to self-reported anxiety at time of testing. Results are discussed in terms of thyroid hormone activation of the prefrontal cortex, which is thought to be the cerebral substrate underlying the shift and disengage functions of attentional processing.

Anxiety↗