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Biomedical subjects

L J Weber

Publications and source records attributed to L J Weber.

At least 19 recordsLinked to original sources
PubMed1989

Oxidation of cardiac myoglobin in vivo by sodium nitrite or hydroxylamine.

A non-vascularized fish heart model was used to assess the oxidation of cardiac myoglobin in vivo by compounds known to cause methemoglobinemia. Buffalo sculpin (Enophrys bison) were cannulated from the afferent branchial artery to permit repeated blood sampling and injected intraperitoneally with sodium nitrite, hydroxylamine or aniline. Methemoglobin was formed by sublethal levels of sodium nitrite or hydroxylamine. For hydroxylamine, the time to peak effect was less than 1 h. For sodium nitrite, the onset was less rapid and the effect more prolonged. Aniline had no effect on hemoglobin at any concentration tested. Cardiac myoglobin, assayed at the time of peak effect on hemoglobin, was oxidized in a dose-dependent manner by sodium nitrite or hydroxylamine. At high doses of sodium nitrite (50 and 100 mg/kg), the oxidation of myoglobin exceeded that of hemoglobin. The reverse was true of hydroxylamine at all concentrations tested. This study suggests that possibility that cardiac myoglobin is oxidized in occupational or other exposures to sodium nitrite, hydroxylamine and related compounds.

Animals↗
PubMed1989

Comparative oxygen affinity of fish and mammalian myoglobins.

Myoglobins from rat, coho salmon (Oncorhynchus kisutch), buffalo sculpin (Enophrys bison) hearts, and yellowfin tuna (Thunnus albacares) red skeletal muscle were partially purified and their O2 binding affinities determined. Commercially prepared sperm whale myoglobin was employed as an internal standard. Tested at 20 degrees C, myoglobins from salmon and sculpin bound O2 with lower affinity than myoglobins from the rat or sperm whale. Oxygen binding studies at 12 degrees C and 37 degrees C suggest that this difference is adaptive, permitting myoglobins from cold-adapted fish to function at physiologically relevant temperatures. Taken together, purification and O2 binding data obtained in this study reveal a previously unrecognized diversity of myoglobin structure and function.

Animals↗
PubMed1984

Effects of neuromuscular blocking agents and acetylcholinesterase inhibitors on the response of pectoral fin muscle of the sculpin (Enophrys bison) to indirect stimulation.

The neuromuscular junction of the buffalo sculpin (Enophrys bison) was characterized in situ by examining the effects of various neuromuscular blocking agents and acetylcholinesterase inhibitors (ACHE-I) on pectoral muscle response to indirect stimulation. The injection of either d-tubocurarine (350 micrograms/kg) or alpha-bungarotoxin (alpha-Butx) (1 mg/kg) resulted in a flaccid paralysis. The depolarizing agents, succinylcholine (11 micrograms/kg) and decamethonium (42 micrograms/kg), produced a spontaneous contraction. The administration of the ACHE-I, diisopropyl fluorophosphate (DFP), and eserine resulted in responses which were contrary to those expected based on similar experiments using mammalian skeletal muscle. Twitch potentiation did not occur and the ability to maintain a tetanic response was not abolished even after the administration of clearly lethal concentrations of ACHE-I.

Acetylcholinesterase↗
PubMed1977

An outbreak of infectious laryngotracheitis in commercial poultry flocks in Ontario.

An outbreak of infectious laryngotracheitis was observed in Ontario commercial poultry flocks from September 1974 to June 1975. Fifty-five flocks, totalling over 848,770 birds were clinically affected by this disease in the southern region of the province. Sixty-nine percent (38/55) of the exposed flocks were in Wentworth country and the regional municipality of Niagara. Hemorrhagic tracheitis with histological evidence of intranuclear inclusion bodies in syncytia of tracheal epithelial cells were the salient pathological findings.

Animals↗