PubMed Health⌕ Search

Biomedical subjects

G S Ferguson

Publications and source records attributed to G S Ferguson.

6 recordsLinked to original sources
PubMed2001

Integration of bulk and interfacial properties in a polymeric system: rubber elasticity at a polybutadiene/water interface.

Oxidation of the surface of cross-linked 1,4-polybutadiene provided a hydrophilic substrate that reconstructed against hot water to become more hydrophobic. Subsequent equilibration against water at room temperature returned its original hydrophilicity. These temperature-dependent changes in the relative concentrations of hydrophobic and hydrophilic moieties at the polymer/water interface are interpreted as arising from the entropic influence of chain extension, associated with rubber elasticity. As expected, the magnitude of this effect depended on the cross-link density of the polymer and the degree of oxidation of the surface. The reversibility of the reconstruction when the water was cycled between high and low temperature damped out only gradually over many cycles.

Journal Article↗
PubMed1997

Dorsal approach to presacral biopsy: technical case report.

OBJECTIVE AND IMPORTANCE: Biopsy of the presacral space is often awkward, technically difficult, and unrewarding when the sacrum is intact and the procedure is performed either by open operation or with computed tomographic guidance through the abdomen or perineum. CLINICAL PRESENTATION: We describe a patient with metastatic adenocarcinoma who presented with leg pain and computed tomographic evidence of a high, small mass anterior to an intact sacrum. TECHNIQUE: By drilling a hole through the sacrum lateral to the canal and between the roots, a biopsy of such a mass may be performed easily, safely, and quickly. CONCLUSION: A dorsal approach to presacral biopsy may be easily performed with readily available technology.

Adenocarcinoma↗
PubMed1986

Rapid and brief tolerance to (+)- and (-)-nicotine in unanesthetized rats.

When given intravenously to unanesthetized rats as a bolus dose, (-)-nicotine produced a dose-related rise in blood pressure and fall in heart rate in the dose range of 5-40 micrograms/kg. Tolerance did not develop when doses were given at 30 min intervals. At the highest dose, the effects on heart rate persisted. In addition, severe arrhythmias and apnea were observed. (+)-Nicotine at 100 micrograms/kg produced effects similar to 10 micrograms/kg of (-)-nicotine. When given at 1 min intervals, tolerance quickly developed after only 6 injections at 5 micrograms/kg and after 4 injections at 10 micrograms/kg. Tolerance to (+)-nicotine also developed rapidly and was no longer evident at 5 min. The results suggest the tolerance is related to frequency of administration and dose. The implication of these results are discussed with regard to cardiovascular disease and dependence. In addition, we postulate that the relatively low degree of biological stereoselectivity of the optical isomers of nicotine, compared with that of the enantiomers of morphine, is due to the simplicity and flexibility of the nicotine molecule. It can be shown using Dreiding models that the nitrogen atoms in the enantiomers are nearly superimposable.

Animals↗
PubMed1978

Treatment and traumatic hemobilia with angiographic embolization.

Hemobilia is an uncommon but devastating complication of liver trauma. The recommended treatment is surgical resection of the involved liver lobe, but this is associated with high mortality and morbidity. An alternate treatment using emboli directed selectively into the involved hepatic artery was successful in obliterating the false aneurysm and eliminating the liver cavity. Since arteriography is generally performed during the diagnostic workup of such patients, embolization may provide a simple, safe, and effective treatment for hemobilia.

Adult↗