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Biomedical subjects

J G Gallagher

Publications and source records attributed to J G Gallagher.

28 records · Page 2Linked to original sources
PubMed1977

Physical properties of the dimyristoylphosphatidylcholine vesicle and of complexes formed by its interaction with apolipoprotein C-III.

The structure of a single bilayer vesicle of dimyristoylphosphatidylcholine has been characterized by sedimentation, densimetry, and light-scattering measurements. The molecular weight, partial specific volume, Stokes radius, and degree by hydration were found to be 2.68 X 10(6), 0.972 cm3/g, 125 A, and 0.86 g/g, respectively. From these quantities, a spherically symmetrical model has been derived that features a phospholipid bilayer 35.5 A thick and a hydration shell 9.3 A thick. This particle was shown to bind apolipoprotein C-III (apoC-III) up to 0.08 g/g without loss of its original vesicular structure. At protein-lipid ratios in excess of 0.08 g/g, sedimentation, gel chromatography, and light-scattering measurement indicated a dramatic decrease in Stokes radius and molecular weight. The sedimentation data showed these parameters to become constant at protein-lipid ratios in excess of 0.25 g/g. In this region, the Stokes radius and molecular weight were found to be approximately 80 A and 442 000, respectively. Within the constraints of these values and other data, several models for this complex are discussed.

Apolipoproteins↗
PubMed1977

Investigation of the aggregation and activation of prothrombin using quasi-elastic light scattering.

The technique of quasi-elastic light scattering was used to measure the translational diffusion coefficient, D, of purified human prothrombin in buffered aqueous solutions and to monitor for the first time the fragmentation of this protein as it is converted to thrombin. The values of D20,w, measured at two different concentrations, are 4.72 X 10(-7) CM2/S at 2MG/CM3 and 4.51 X 10(-7) CM2/S at 5MG/CM3; the corresponding molecular weights (Mw of 92 000 and 120 000), obtained by combining sedimentation velocity measurements with the diffusion data, confirm the presence of molecular aggregates of prothrombin in these solutions. These results, as well as analysis of the intensity-intensity autocorrelation functions from two-component systems with various dimer conformations, indicated the presence of end-to-end dimers in these prothrombin solutions. The values obtained for D indicate a dimer weight fraction of 0.4 to 0.5 in the 2 mg/cm3 solution and 0.6 or greater in the 5 mg/cm3 solution. The fragmentation of prothrombin was monitored in a nonphysiologic activation system, containing taipan snake venom, dihexanoylphosphatidylcholine, and CaCl2. At a temperature of 15 degrees C, conversion to thrombin proceeded very slowly and was still incomplete after 90 h. A method for determing the percentage of converted prothrombin is an activated system containing aggregates from the average value of D and light scattering data is discussed.

Chemical Phenomena↗
PubMed1972

Adenovirus susceptibility to human interferon during one-step replication.

Susceptibility of adenovirus types 2, 7, and 12 to human interferon was measured in three human diploid cell strains during a single-cycle infection. Although the relative susceptibility of adenovirus to interferon varied in these cell strains, the final yield of each type in each cell strain decreased as the interferon dose increased. On the other hand, wide difference in interferon susceptibility of adenoviruses and vesicular stomatitis virus (VSV) was noted, as interferon doses above 100 units profoundly inhibited VSV but not the adenoviruses.

Adenoviridae↗
PubMedDate not supplied

Sudden hemiparesis as the presenting sign in cryptococcal meningoencephalitis.

A previously healthy young man presented with an acute stroke syndrome and was found to have cryptococcal organisms in the CSF. Though an initial CSF examination for an infectious etiology was negative, a second lumbar puncture was performed because of hypoglycorrhachia, which established the diagnosis. An uneventful recovery followed the administration of Amphotericin B and 5-Flucytosine. A literature search revealed only one previously reported case of cryptococcal meningoencephalitis presenting as a stroke. The need for performing a CSF examination on young patients presenting with a cerebrovascular event, and the aggressive investigation of unexplained hypoglycorrhachia are emphasized.

Adult↗
PubMedDate not supplied

Double-blind crossover trial of droperidol, metoclopramide, and prochlorperazine as antiemetics in cisplatin therapy.

Droperidol, metoclopramide, and prochlorperazine were compared in a double-blind crossover trial to determine their relative effectiveness in preventing and controlling the nausea and vomiting caused by cisplatin-containing chemotherapy. Twenty-five patients receiving cisplatin-containing chemotherapy for various malignancies were entered into this trial with 14 patients completing the three-drug randomization sequence. This was the patient's first exposure to cisplatin. Each antiemetic was administered in a diluted 50 ml i.v. injection over 15 minutes beginning 0.5 hour before cisplatin and 1.5, 3.5, 5.5, and 8.5 hours after cisplatin. Dosages of antiemetics for doses of cisplatin greater than or equal to 100 mg/sq m were droperidol 2.5 mg, metoclopramide 2 mg/kg, or prochlorperazine 5 mg in each infusion. For doses of cisplatin less than 100 mg/sq m, the dosages were droperidol 2.5 mg for the first two doses and 1.25 mg for subsequent doses, metoclopramide 1 mg/kg, or prochlorperazine 5 mg for each dose. The median number of emetic episodes for the first 24 hours were as follows: droperidol 3.2; metoclopramide 1.8; prochlorperazine 3.7. There was a significant difference in number of emetic episodes demonstrating antiemetic superiority of metoclopramide over both droperidol and prochlorperazine. For these 14 patients completing the trial, eight preferred metoclopramide, two preferred prochlorperazine, one preferred droperidol, and three had no preference. At the doses used in this study, the antiemetic efficacy of metoclopramide was superior to either droperidol or prochlorperazine.

Adult↗