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Biomedical subjects

M Riedy

Publications and source records attributed to M Riedy.

4 recordsLinked to original sources
PubMed1991

Introduction of foreign genes into tissues of living mice by DNA-coated microprojectiles.

Foreign genes were expressed in liver and skin cells of live mice by using a new apparatus to accelerate DNA-coated microprojectiles into tissues. After introduction of a plasmid in which the firefly luciferase gene was controlled by the human beta-actin promoter, luciferase activity was detectable for up to 14 days in mouse tissues (skin and liver). In situ hybridization histochemistry revealed that microprojectiles penetrated through multiple cell layers without evidence of tissue injury and that 10-20% of the cells in the bombarded area expressed the foreign gene. An advantage of the new design is that internal organs, such as liver, can be transfected without subjecting the tissue to a vacuum. This procedure potentially is applicable to a wide variety of tissues and cell types for studies of transcriptional control elements and for expression of foreign proteins in intact animals.

Actins↗
PubMed1989

Cardiac adaptations to endurance training in rats with a chronic myocardial infarction.

The hemodynamic response to maximal exercise was determined in sedentary and trained rats with a chronic myocardial infarction (MI) produced by coronary artery ligation and in rats that underwent sham operations (SHAM). Infarct size in the MI groups of rats comprised 28-29% of the total left ventricle and resulted in both metabolic and hemodynamic changes that suggested that these animals had moderate compensated heart failure. The training regimen used in the present study produced significant increases in maximal O2 uptake (VO2max) when expressed in absolute terms (ml/min) or when normalized for body weight (ml.min-1.kg-1) and consisted of treadmill running at work loads that were equivalent to 70-80% of the animal's VO2max for a period of 60 min/day, 5 days/wk over an 8- to 10-wk interval. This training paradigm produced two major cardiocirculatory adaptations in the MI rat that had not been elicited previously when using a training paradigm of a lower intensity. First, the decrement in the maximal heart rate response to exercise (known as "chronotropic incompetence") found in the sedentary MI rat was completely reversed by endurance training. Second, the downregulation of cardiac myosin isozyme composition from the fast ATPase V1 isoform toward the slower ATPase (V2 and V3) isoforms in the MI rat was partially reversed by endurance training. These cardiac adaptations occurred without a significant increase in left ventricular pump function as an increase in maximal cardiac output (Qmax) and maximal stroke volume (SVmax) did not occur in the trained MI rat.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1979

Radiochemical plasma salicylamide assay using ring-labeled tritiated salicylamide.

A rat plasma salicylamide assay was developed using ring-labeled tritiated salicylamide, synthesized by reacting salicylamide with tritium oxide in the presence of heptafluorobutyric acid. The reaction yielded 3H-salicylamide of specific activity up to 8.41 mCi/mmole, 60% yield. Plasma containing 3H-salicylamide and its metabolites was extracted with a toluene-based scintillation fluid, which was subsequently counted. Specificity for free salicylamide was demonstrated by radio chemical and standard fluorescence plasma salicylamide level-time curves. Specificity resulted from nonextraction of the salicylamide sulfate and glucuronide metabolites. Sulfatase and beta-glucuronidase treatment allowed the analysis of plasma sulfate and glucuronide conjugates as free salicylamide. This procedure should be effective for the analysis of salicylamide and its metabolites in the presence of similar phenolic compounds.

Animals↗