Thomas Forrester

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Local regulation of microvascular blood flow is a complex process in which the needs of the tissue must be communicated to the vasculature, enabling the appropriate matching of O2 supply to demand. We hypothesize that the red blood cell is not only the major O2 carrier but also serves as an O2 sensor and affecter of changes in O2 delivery via its release of(More)
OBJECTIVE The aims were, first, to detect and quantify the release of ATP from human erythrocytes in response to a brief exposure to a hypoxic/hypercapnic environment, similar to that found in vigorously exercising skeletal or cardiac muscle; and second, to explore the mechanism of ATP release in response to hypoxia. METHODS Washed human erythrocytes(More)
1. Active frog sartorius muscle in vitro liberates a substance into the bathing solution which has a pronounced stimulatory action on the frog heart.2. The stimulatory effect is not due to an increase in the K(+) concentration of the bathing solution, nor is it due to the liberation of catecholamines.3. In a molecular sieve chromatography procedure the(More)
1. Human subjects performed a sustained contraction of the forearm muscles for 4 min in the presence of arterial and venous occlusion.2. The contraction was maintained at 5% of the maximum voluntary contraction, a tension during which the muscle blood flow might be expected to increase by about three times (Lind & McNicol, 1967).3. Adenosine triphosphate(More)
Curarized and non-curarized rat hemidiaphragm muscles were indirectly stimulated in vitro. 2. The fluid bathing the active curarized muscles was eluted through a dextran gel (Sephadex G-10), effecting a complete separation of ACh from curare. The acetylcholine fraction was then assayed on an isometric leech muscle preparation. 3. Prostaglandin (PGE1) in a(More)
Estradiol (E2) regulation of estrogen receptor (ER) concentrations has been shown to be both time- and dose-dependent. E2 concentrations of 0.5 mg/ml or greater contained in Silastic capsules suppressed uterine ER concentrations after one day's exposure. In this study, we looked at the effects of physiological (1.0 and 10.0 micrograms subcutaneous(More)
1. Adult rat heart cells were isolated enzymically and ATP was identified in the cell suspension using the firefly luminescence technique. Adenosine 5'-triphosphate (ATP) was not detected from cell suspensions obtained from hearts which had been left asystolic for 10 min.2. It was found that ATP 0.34 +/- 0.22 muM/mg protein was released by cells kept in an(More)
1. When diluted human plasma is perfused through a frog heart, a marked augmentation of the heartbeat is produced which is very similar in action to that of low concentrations of adenosine triphosphate (ATP) on the heart.2. It was established that the substance in the plasma responsible for the heart stimulation was ATP. The following tests were used: (a)(More)
1. A working rat heart preparation was used to study the release of adenosine-5'-triphosphate (ATP) into the coronary sinus effluent in response to hypoxia. 2. The left ventricle was set to pump against an hydrostatic pressure of 65 cm water; the left atrial filling pressure was kept constant at 10 cm water. The power output of the heart at these pressures(More)