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Biomedical subjects

M Woods

Publications and source records attributed to M Woods.

At least 163 records · Page 9Linked to original sources
PubMed1979

An intraspinal sympathetic preganglionic pathway: physiologic evidence in the cat.

Electrical stimulation of the zona intermedia of the lower thoracic/upper lumbar cat spinal cord resulted in increases of heart rate (HR), blood pressure (BP) and cardiac contractility (dp/dt). Sites of maximal cardiovascular response (SMCR) were localized histologically to the intermediolateral nucleus (ILN). The inotropic and chronotropic responses were abolished by spinal cord transection or hemisection two to three segments rostral to the site of stimulation. Discrete electrolytic lesions in the white matter adjacent to the ILN were also shown to markedly decrease or abolish the chronotropic and inotropic responses elicited by stimulation of a more caudal SMCR. Longitudinal spinal section resulted in decreased cardiovascular responses from an SMCR; these changes were larger on the left side and greatest for BP as compared to HR and dp/dt. These findings indicate the existence of an ascending intraspinal cardiovascular pathway located in the deep white matter adjacent to the ILN. They further suggest that this is the intraspinal sympathetic preganglionic pathway recently described anatomically.

Animals↗
PubMed1979

Marrow autotransplantation accelerates haematological recovery in patients with malignant melanoma treated with high-dose melphalan.

In a Phase I study, melphalan 140 mg/m2 was administered to 8 patients with disseminated malignant melanoma. Marrow was removed from the patients immediately before melphalan administration and returned i.v. 8 h later. Studies on marrow culture and melphalan pharmacokinetics predicted that this was a safe time to administer non-cryopreserved marrow. Four patients received lower doses of i.v. melphalan without autologous marrow. In the group receiving autologous marrow the time for recovery of peripheral-blood granulocytes to 800/mm2 or greater was significantly less (P = 0.01) than in those not receiving marrow. In 7 patients the tumour showed evidence of response to the drug and there was 1 complete remission. This treatment deserves investigation in patients with tumours more sensitive to drugs than melanoma.

Adult↗
PubMed1978

Inhibition of erythrocyte sickling in vitro by pyridoxal.

To test the antisickling activity of pyridoxal, we compared the oxygen affinity and the percent sickling at low PO2 of untreated erythrocytes with values for cells from the same blood sample incubated with pyridoxal, glyceraldehyde, or pyridoxine. Pyridoxal increased oxygen affinity much more than glyceraldehyde. 20 mM pyridoxal and glyceraldehyde had equivalent antisickling activity. At PO2 levels above 20 mm Hg, both agents reduced sickling to less than 2%. In samples examined by electron microscopy, pyridoxal reduced the percent sickled cells and the percent cells that contain hemoglobin S fibers by the same amount (from 74 to 3%). Pyridoxine had no effect on oxygen affinity or sockling. Pyridoxal reacts with intracellular hemoglobin to increase oxygen affinity, which inhibits hemoglobin S polymerization and sickling.

Anemia, Sickle Cell↗
PubMed1977

The influence of coronary arterial pH on myocardial oxygen demand.

The purpose of this study was to examine the magnitude of the influence of coronary arterial pH (pHa) on myocardial oxygen uptake (MV 02). In order to isolate and control the recognized determinants of MV02, a perfused heart preparation was developed which permitted control of heart rate and pressure and flow work. A perfusion system was used which allowed independent regulation of O2 N2 and CO2 flow to a membrane lung and precise control of coronary blood flow. Myocardial oxygen delivery (Ca02 x flow) could be held constant (+/- 1%) during 4 hours of perfusion. Catheter decompression of both ventricles prevented any external pressure or flow work. Blood temperature was maintained at 37.27 +/- 0.07degrees C. Perfusing blood pH was related initially to spontaneous heart rate in five dogs: pulse = 82 pH - 487. In 12 subsequent animals heart rate was fixed. MV02 was directly and significantly related to coronary arterial pH in all animals studied: MVO2% = 109 pH - 143 (r = 0.823). An increase in pHa of 0.1 will increase MV02 by 10.9%. This study isolates pH as a determinant of myocardial oxygen uptake and indicates that progressive alkalosis induces increased myocardial oxygen uptake. This must be recognized in the treatment of patients with compromised myocardial function and rerional areas of ischemia.

Alkalosis↗
PubMed1976

Tracheal stenosis. A method of dilation with use of the fiberoptic bronchoscope.

Tracheal stenosis is not an uncommon sequel of prolonged endotracheal intubation. In some cases, immediate reconstruction is not feasible. We use the flexible fiberoptic bronchoscope and a lucent, tapered endotracheal tube for tracheal dilation. The fiberoptic bronchoscope is passed through a special T connector into the endotracheal tube and used to guide the tube under direct vision through the stricture.

Adult↗
PubMed1976

The influence of oxyhemoglobin affinity on tissue oxygen consumption.

In an intact animal or patient, any shift in oxyhemoglobin affinity is inevitably associated with concurrent fluctuation in numerous other determinants of oxygen delivery. For this reason, the influence of hemoglobin affinity for oxygen on tissue oxygen consumption has been incompletely evaluated. The purpose of this study was to investigate the influence of oxyhemoglobin affinity as the sole variable of oxygen delivery in an isolated perfused canine hindlimb. A membrane lung system which allowed precise control of blood flow, temperature, arterial oxygen content and arterial pH was established. Twelve isolated canine hindlimbs were alternatively perfused with autologous stored (left-shifted) and fresh (right-shifted) blood in paralled perfusion systems. The 2,3-DPG concentrations, P50 and oxygen consumptions were significantly different in the two paralled perfusion systems. A decreased hemoglobin affinity for oxygen appeared to permit increased oxygen off-loading at the tissue level.

Animals↗