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Biomedical subjects

K M Chan

Publications and source records attributed to K M Chan.

275 records · Page 16Linked to original sources
PubMedDate not supplied

Testing for drugs of abuse in meconium of newborn infants.

A reliable and sensitive screening procedure has been developed for drugs of abuse (amphetamines, cocaine metabolites, opiates, and phencyclidine [PCP]) in meconium from infants. The substances in meconium were extracted with chloroform-isopropanol (3:1) and screened by enzyme multiplied immunoassay technique (EMIT). The lower detection limits of the EMIT for benzoylecgonine, d-methamphetamine, morphine, and PCP were 250 ng/g, 730 ng/g, 110 ng/g, and 100 ng/g, respectively. This method was applied to meconium from 50 infants born to mothers suspected of using the drugs of abuse during pregnancy. Of the 50, 12 were positive for benzoylecgonine, seven for opiates, and one for PCP. The presence of benzoylecgonine and PCP in meconium was confirmed by gas chromatography/mass spectrometry and that of opiates by thin-layer chromatography. The routine analysis of meconium for drugs of abuse is recommended in cases where (A) urine can not be obtained or (B) urinalysis is negative for the substances despite a strong suspicion of maternal use of the substances during pregnancy.

Cocaine↗
PubMedDate not supplied

Functional electrical stimulation using microstimulators to correct foot drop: a case study.

This paper presents a case study that tested the feasibility and efficacy of using injectable microstimulators (BIONs) in a functional electrical stimulation (FES) device to correct foot drop. Compared with surface stimulation of the common peroneal nerve, stimulation with BIONs provides more selective activation of specific muscles. For example, stimulation of the tibialis anterior (TA) and extensor digitorum longus (EDL) muscles with BIONs produces ankle flexion without excessive inversion or eversion of the foot (i.e., balanced flexion). Efficacy was assessed using a 3-dimensional motion analysis of the ankle and foot trajectories during walking with and without stimulation. Without stimulation, the toe on the affected leg drags across the ground. BION stimulation of the TA muscle and deep peroneal nerve (which innervates TA and EDL) elevates the foot such that the toe clears the ground by 3 cm, which is equivalent to the toe clearance in the less affected leg. The physiological cost index (PCI) measured effort during walking. The PCI equals the change in heart rate (from rest to activity) divided by the walking speed; units are beats per metre. The PCI is high without stimulation (2.29 +/- 0.37, mean +/- SD) and greatly reduced with surface (1.29 +/- 0.10) and BIONic stimulation (1.46 +/- 0.24). Also, walking speed increased from 9.4 +/- 0.4 m/min without stimulation to 19.6 +/- 2.0 m/min with surface and 17.8 +/- 0.7 m/min with BIONic stimulation. These results suggest that FES delivered by a BION is an alternative to surface stimulation and provides selective control of muscle activation.

Adult↗
PubMedDate not supplied

What about tetanus?

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Clostridium tetani↗