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Biomedical subjects

B R Brown

Publications and source records attributed to B R Brown.

113 records · Page 7Linked to original sources
PubMed1966

The leaf tannin of willow-herb [Chamaenerion angustifolium (L.) Scop.].

1. The leaf tannin of willow-herb [Chamaenerion angustifolium (L.) Scop.] has been isolated and separated into two fractions of differing solubility. 2. The tannin contains a penta-O-galloyl-beta-d-glucose core to which further galloyl groups are depsidically bound. 3. The unfractionated tannin contains an average of 10.5 galloyl groups/glucose molecule; the soluble fraction has on average 7.6 galloyl groups/glucose molecule and the less soluble fraction has 12.4. 4. The tannin is a mixture of molecules ranging at least from hepta- to trideca-galloyl-beta-d-glucose. 5. The tannin forms complexes with proteins and the fact that it is a hydrolysable gallotannin has a bearing on the release of nitrogen from the protein of the dead leaf.

Chemical Phenomena↗
PubMedDate not supplied

Sevoflurane degradation product concentrations with soda lime during prolonged anesthesia.

STUDY OBJECTIVES: To evaluate the decomposition of sevoflurane in soda lime during prolonged sevoflurane anesthesia in humans. To evaluate for evidence of renal or hepatotoxicity as a result of exposure to these sevoflurane degradation compounds. DESIGN: Prospective evaluation in healthy volunteers. SETTING: Clinical research unit and postanesthesia care unit of a university hospital. PATIENTS: Six healthy male volunteers. INTERVENTIONS: Subjects were anesthetized with sevoflurane 1 to 1.2 minimum alveolar concentration for greater than 9 hours with a semiclosed circuit anesthetic technique (5-liter total flow) with fresh soda lime as the absorbent. MEASUREMENTS AND MAIN RESULTS: Laboratory tests of renal and hepatic function were performed before anesthesia and 1 and 5 days after anesthesia. During sevoflurane anesthesia, inhalation and exhalation circuit limb gas samples were obtained for degradation compound analysis. Only one degradation product, fluoromethyl-2,2-difluoro-1-(trifluoromethyl) vinyl ether (compound A), was detected. Inhalation concentration was maximal (7.6 +/- 1.0 ppm) at 2 hours and did not increase further after this time point. There were no differences in preanesthesia and postanesthesia tests of hepatic and renal function. CONCLUSIONS: Levels of the degradation compound (compound A) produced in semiclosed circuit sevoflurane anesthesia with soda lime are well below potential toxic levels and thus appear safe. When sevoflurane is administered under these conditions for prolonged anesthesia, concentrations of compound A do not continue to increase throughout anesthesia.

Adsorption↗
PubMedDate not supplied

Detection of covalently bound halothane metabolites in the hypoxic rat model for halothane hepatotoxicity.

Using a non-radiometric technique, halothane metabolites have been shown to covalently bind to rat hepatic tissue with the production of a lesion. The conditions required for optimizing the lesion (hypoxia and biotransformation enzyme induction) also optimizes the binding of fluorinated halothane residues to hepatic tissue. The maximal binding of fluorinated halothane residues to the liver of rats precedes the development of the hepatic lesion. Female rats, which are resistant to the halothane initiated lesion, have one-third as much covalently bound halothane residue. Biotransformation inhibitors (SKF-525A, metyrapone), which inhibited lesion formation, also inhibit the covalent binding of halothane to hepatic tissue. Cystamine and cysteine, sulfhydryl agents which can inhibit hepatic lesion development when administered four hr after halothane exposure, also suppressed the amount of halothane metabolites covalently bound to hepatic tissue. Using this non-radioactive method for measuring the covalent binding of halothane to hepatic tissue, it appears that the bioactivation of halothane was a necessary event for the appearance of a halothane initiated hepatic lesion.

Animals↗
PubMedDate not supplied

Anecdotal episodes on Surgical Eye Expeditions (S.E.E.).

1. It is important to share your skills with international colleagues. 2. S.E.E. International offers participants global opportunities and challenges. 3. You can enrich your personal and professional life by helping blind patients to see.

Adaptation, Psychological↗