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G Blumberg

Publications and source records attributed to G Blumberg.

25 records · Page 2Linked to original sources
PubMed1991

A comparison of the Puritan-Bennett 7200a ventilator's flow-by mode to the T-piece mode prior to extubation in postsurgical patients.

UNLABELLED: We compared flow-by ventilation (FB) via the Puritan-Bennett 7200a ventilator with T-piece ventilation (TP) during weaning from mechanical ventilation (MV). METHODS: We placed 22 consecutive postsurgical patients being weaned from MV on FB at base flows of 10 L/min and 20 L/min and then on TP. Blood pressure, pulse rate, respiratory rate, blood gases, tidal volume, and peak inspiratory flow were measured after at least 20 min in each mode. Statistical analysis of clinical status used a three-level, one-way analysis of variance with technique as a within-subjects factor. Setup costs of the three ventilatory modes were evaluated using relative value units for labor plus actual costs of added equipment and supplies. RESULTS: Although there was a statistically significant difference in PaCO2 among the ventilatory modes, this was not clinically important. No other differences were found. Each FB mode cost $2.55 to set up, whereas TP cost $11.90. CONCLUSIONS: FB and TP were clinically equivalent. However, the alarm and monitoring capabilities during FB are useful and may be worth the one-time cost ($1,000) of adding the optional flow-by software to the 7200a ventilator.

Costs and Cost Analysis↗
PubMed1982

Homocystine uptake in isolated rat renal cortical tubules.

Isolated rat renal cortical tubules were used to study the nature of homocystine entry into the tubule cell and its transport interactions with cystine and the dibasic amino acids. The uptake of homocystine with time was progressive, reaching a steady state after 60 min. of incubation. Analysis of the intracellular pool after 5 and 30 min. of incubation revealed that virtually all of the transported homocystine had been converted to other metabolites of the transsulfuration pathway. The major metabolite was cystathionine with a somewhat lesser, but still significant amount as S-adenosylhomocysteine. A kinetic analysis showed that two systems for cellular entry of homocysteine existed with a Km1 of 0.17 mM and a Km2 of 7.65 mM. Arginine and lysine inhibited homocystine uptake via the low Km, high affinity system, but appeared not to inhibit the high Km, low affinity system. Cystine inhibited the low Km, high affinity system, but had an indeterminate effect on the high Km, low affinity system. Homocystine inhibited the uptake of cystine, lysine and arginine by isolated rat renal cortical tubules. The inhibition of homocystine on cystine uptake appeared to occur on both the high and low Km system for tubule cell entry of cystine. The data suggest that the low Km system for homocystine transport is shared with cystine and the dibasic amino acids. These data extend the knowledge of homocystine metabolism and provide a rational basis for new approaches to the treatment of homocystinuria.

Amino Acids↗
PubMed1976

Distribution of bacteria in the velocity gradient centrifuge.

Cells in different parts of the cell cycle can be separated by brief centrifugation in a density stabilized gradient: the Mitchison-Vincent technique. The position of a cell in the tube depends upon its size, shape, and density, upon the gradients of density, viscosity, and centrifugal force through which it sediments, and upon time. A program to compute the velocities and integrate the velocity profile for particles of a particular size class is presented. Because enteric bacteria are a form intermediate between right cylinders and prolate ellipsoids of revolution, the program uses values for the frictional coefficient intermediate between those calculated for ellipsoids and for cylinders. The formula f=6pietab(a/b)1/2 possesses this property and because of its simplicity greatly speeds the calculations. A second program computes the distribution of masses and then of sedimentation constants for a bacterial population, expressed either as a frequency distribution or as total mass per s-class. The effect of the known variation in cell size at division is included in these calculations, which apply to organisms undergoing balanced, asynchronous growth in which mass increase is proportional to cell size. The two programs in conjunction compute the mass or cell-number profile in an arbitrary gradient. The programs have been used to design gradients to maximize the resolution of the technique.

Bacterial Physiological Phenomena↗