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Biomedical subjects

L W Lee

Publications and source records attributed to L W Lee.

77 records · Page 5Linked to original sources
PubMedDate not supplied

Identification of kinetic differences between fallers and nonfallers in the elderly.

Falls are a major cause of decreased mobility and disability in the elderly. Multiple factors are believed to contribute to falling. Among these, gait abnormalities have drawn attention as a possible risk factor. Although previous studies have revealed few differences in gait parameters compared with similar aged controls, it was hypothesized that because of intrinsic differences in balance and motor control, we would observe differences in joint kinetics. In this study, 15 subjects (mean age, 77 +/- 9 yr), who had at least 2 mo of repeated falls from an unclear cause, were evaluated in a gait laboratory and were compared with a control group of 15 subjects (mean age, 75 +/- 5 yr) with no history of falls. Analysis of data demonstrated a significantly greater peak torque in the falls group for the following: hip flexion, hip adduction, knee extension, knee varum, ankle dorsiflexion, and ankle eversion (P < 0.003 in each comparison). Also, ankle plantarflexion torque was significantly decreased in the falls group (P = 0.001). Joint powers showed different absorption at the knee and ankle in the falls group. The discovery of these kinetic differences may provide further insight into the mechanism of falls in the elderly and, more importantly, lead to identifiable markers to detect those who may be susceptible to falls.

Accidental Falls↗
PubMedDate not supplied

Inhibitory mechanisms of naloxone on human platelets.

1. In the present study, naloxone was tested for its antiplatelet activities in human platelet-rich plasma (PRP). In human PRP, naloxone (0.1-0.5 mmol/L) inhibited aggregation stimulated by a variety of agonists (i.e. collagen, adenosine diphosphate (ADP), U46619 and adrenaline). 2. Naloxone (0.1-0.5 mmol/L) did not significantly affect cyclic adenosine monophosphate and cGMP levels in human washed platelets, whereas naloxone (0.5 mmol/L) significantly inhibited thromboxane B2 formation stimulated by collagen (5 micrograms/mL) in human washed platelets. 3. Naloxone (0.5 mmol/L) significantly inhibited [3H]-inositol monophosphate formation of [3H]-myoinositol-loaded platelets stimulated by collagen and U46619. Moreover, naloxone did not influence the binding of 125I-triflavin to platelet membranes. Triflavin is an Arg-Gly-Asp-containing specific fibrinogen receptor antagonist. 4. Addition of naloxone (0.5 mmol/L) to platelet preparations tagged with diphenylhexatriene (DPH) resulted in a considerable decrease in relative fluorescence intensity. 5. It is suggested that the anti-platelet effects of naloxone may be caused, at least partly, by the induction of conformational changes in the platelet membrane initially, followed by the inhibition of thromboxane A2 formation and phosphoinositide breakdown of platelets stimulated by agonists.

Blood Platelets↗
PubMedDate not supplied

Energy metabolism during brain ischemia. Stability during reversible and irreversible damage.

The permissible duration of brain ischemia without sustaining damage is short. Less clear are the mechanisms accounting for the vulnerability of brain to ischemic insults. Neurochemical factors implicated include impairment of energy synthesis by mitochondria and of energy-dependent processes such as synaptic transmission, ATPase activity, membrane conductance and altered protein and lipid synthesis. To clarify the vulnerability of energy metabolism, we investigated energy availability and synthesis in our model of global cerebral ischemia. Our studies evaluated in vitro mitochondrial ATP synthesis and the in vivo quantitation of the cortical adenylate pool. Results of our investigations support a growing body of evidence showing the energy state to be relatively stable to ischemia. We conclude that an energy-dependent process of brain is primarily vulnerable to ischemia.

Adenosine Diphosphate↗
PubMedDate not supplied

The role of temperament in pediatric pain response.

This study explores the role of temperament in pediatric pain perception and responses. The sample consisted of 3- to 7-year-olds (N = 137) who required preoperative blood test by venipuncture. Blood sampling procedures were videotaped. Children's pain responses were measured by their behaviors, pulse oximetry, and self-report of pain. Parents reported their child's usual pain behaviors, previous pain experiences, and temperament. The temperament category threshold was found to relate to self-report and distress behaviors during the preparation phase. The temperament categories of activity, mood, approach, adaptability, intensity, and threshold related to children's previous pain responses and usual pain behaviors. These previous behaviors were strong predictors for their responses to venipuncture pain.

Child↗