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Biomedical subjects

C Siew

Publications and source records attributed to C Siew.

29 records · Page 2Linked to original sources
PubMed1984

Gingiva as a site for xenobiotic metabolism in rats.

NADPH-dependent N-demethylation of aminopyrine and tripelennamine and hydroxylation of aniline, phenytoin and tripelennamine occurred in rat gingival homogenates. The metabolic profile in gingiva appeared to be similar to that in liver, the major organ in the body for the metabolism of these xenobiotics.

Aminopyrine↗
PubMed1978

Osmotic minipumps for administration of barbital to mice: demonstration of functional tolerance and physical dependence.

Sodium barbital was administered to mice at a constant rate by miniature osmotic pumps implanted subcutaneously. Each pump delivered approximately 0.25 mg/hr. With two pumps per mouse, blood barbital levels of 20 to 30 microgram/ml could be maintained for various periods. Barbital was assayed by gas chromatography. Functional tolerance was shown by a significant decrease in sleep time after a challenge dose of barbital administered 24 hours after withdrawal. Physical dependence was demonstrated by withdrawal hyperexcitability as measured either with pentylenetetrazol or by convulsions elicited by handling.

Animals↗
PubMedDate not supplied

Examination of blood levels of mercurials in practicing dentists using cold-vapor atomic absorption spectrometry.

The toxicity of mercury compounds in dentistry has been an issue of increasing concern. Relatively few data are available concerning the possible in vivo biotransformation of elemental mercury from dental amalgam into more toxic organic mercurials. The present study was designed to evaluate the existence of this in vivo pathway in dentists who work in a confined environment where metallic mercury vapor is constantly present. Two hundred five practicing dentists and 24 nondental controls were asked to participate in this study. The total, inorganic, and organic mercury contents of blood were determined by syringe-injection cold-vapor atomic absorption spectrometry. The student t-test indicates that the total and inorganic mercury levels in blood are significantly different between dentists and nondental controls at the significant level of p less than or equal to 0.05. The organomercurial levels are, however, insignificant at the same test level. This implies that high total and inorganic mercury levels are not correlated with high organomercurial levels in the blood of practicing dentists. Therefore, significant enzymatic conversion of inorganic to organic mercury compounds does not occur in vivo.

Dentists↗