Search PubMed⌕ Search

Biomedical subjects

G Adams

Publications and source records attributed to G Adams.

At least 109 records · Page 6Linked to original sources
PubMed1991

Microwave blood plasma defroster.

A microwave blood plasma defroster capable of thawing up to four bags of frozen blood plasma at a time is described. The unit stops automatically when the plasma reaches a preset temperature, and all operating parameters are monitored for safety. Comparative testing showed that blood plasma thawed in this device was indistinguishable from plasma thawed in a water bath.

Equipment and Supplies↗
PubMed1989

Cochlear implant hearing performance at the University of Minnesota.

The hearing performance of six post-lingually deaf adults implanted with the Nucleus 22-channel device are presented. All patients achieved measurable open set speech recognition with implant alone. The best hearing performance was achieved with a combination of lipreading and cochlear implant. For this condition our group achieved an average open set speech discrimination score of 85% (CID sentences) and an average speech tracking rate of 70 words per minute. We attribute the success of our group to careful pre-operative selection, including attention to candidate motivation toward hearing rehabilitation.

Adult↗
PubMed1988

Kinetics and mechanisms of vinpocetine degradation in aqueous solutions.

Under stressed conditions, vinpocetine (1; ethyl apovincamin-22-oate) equilibrates with vincaminic acid ethyl ester (2) and 14-epivincaminic acid ethyl ester (3), and hydrolyzes to apovincaminic acid (4). Sequentially, 2 is equilibrated with 14-epivincaminic acid ethyl ester (3) and hydrolyzes to vincaminic acid (5), which equilibrates with 4 and 14-epivincaminic acid (6). At acidic pH, the major route of degradation is 1 in equilibrium 2----5. However, at neutral pH, the major route of degradation is 1----4 in equilibrium 5. The kinetics for the degradation of 1 in the pH 1-3 region is represented by a consecutive reaction with a reversible step (second-order), but the degradation of 1 in the pH 3.5-6.0 region follows pseudo first-order kinetics. Significant buffer catalysis is observed with acetate and phosphate buffers. Reactions are dependent on the ionic strength, pH, and temperature. No oxygen effect on the degradation of vinpocetine is found.

Buffers↗
PubMed1988

Preformulation study of pelrinone hydrochloride.

Pelrinone HCl is essentially nonhygroscopic. The pH-solubility profile exhibits a U-shaped curve, while the octanol-water partition coefficient-pH profile shows a bell-shaped curve. Two ionizable functions, with a pKa1 value of 4.71 and a pKa2 value of 8.94, produce the cationic and anionic forms, respectively. A weak ionic strength effect on solubility of the compound is observed: at pH 3.9 (0.1 M acetate buffer), the solubility increases with increasing ionic strength, while at pH 7.5 (Tris HCl buffer), the solubility decreases with increasing ionic strength. No gross incompatibility of the compound is seen with the 13 excipients selected, except povidone. The solubility phase diagram, X-ray diffraction pattern, and IR spectroscopy demonstrate the presence of polymorphs. The compound in solution is stable at various pH conditions under 500-foot-candle (ft-c) light at room temperature and at 80 degrees C for 64 d. In the solid state, no decomposition is observed at 80 degrees C and on exposure to 500-ft-c light for at least 112 d.

Cardiotonic Agents↗
PubMed1988

Structural and immunochemical aspects of Brucella abortus endotoxins.

Smooth lipopolysaccharide (sLPS) of Brucella abortus, which is the most immunodominant component among the antigens of B. abortus isolated, has been used for diagnosis for decades. High yields of sLPS can be prepared by a modification of the procedures of Moreno et al. (J. Bacteriol. 138:361-369, 1979). Washed B. abortus cells can be disrupted by 21 freeze-quick thaw cycles and ultrasonication to separate non-membrane-bound material; then phenol extraction is performed 3 times and the phenol fraction is washed with H2O intensively. The membrane-bound sLPS can be fractionated into 3 to 5 groups according to the extent of dialysis and centrifugation. These membrane bound sLPS fractions show marked individual differences in their precipitin profile and chemical composition. Their protein content varies from 16% to 42% as determined by dye binding test and 17 to 60% by Lowry phenol method using bovine serum albumin as the standard, which indicates that these proteins associated with LPS may play important roles in the immunochemical interactions, solubility, and the heterogeneity of B. abortus lipopolysaccharides. Compared to previously published methods, a higher yield of sLPS, ranging from 3.6% to 7.7% of dried bacteria, is obtained. Group f5A, which has a standard bell shaped curve in the precipitin assay, is one of the major fractions in all three strains (1119.3, 19, 2308). The protein free sLPS (less than 1% of Lowry reactive component) can be prepared by pronase digestion. The immunochemical reactivity remains about the same before and after this treatment. The O-chains of the major fraction (f5A) of B. abortus (Strains 2308 and 19) membrane bound smooth lipopolysaccharide (sLPS) are obtained by hydrolysis of f5A native sLPS in 1% acetic acid at 100 degrees C for 2 hours. After hydrolysis, the O-chains are separated from the lipid A protein complex by centrifugation, and from small fragments by ultrafiltration of a molecular weight cut-off (MWCO) of 1.0 x 10(3). These carbohydrate haptens can be identified by precipitin-inhibition assay and further fractionated by both membrane filtration and dialysis. The size distributions of carbohydrate haptens of the endotoxins (f5A) ranged from several oligosaccharides up to 1.0 x 10(4) MWCO. Three major fractions of MWCO 8.0-10.0 x 10(3), 3.5-5.0 x 10(3), and less than 1.0 x 10(3) for both strains 2308 and 19 contain more than 85% of the total immunreactive materials.(ABSTRACT TRUNCATED AT 400 WORDS)

Brucella abortus↗