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Biomedical subjects

M Luzzana

Publications and source records attributed to M Luzzana.

50 records · Page 3Linked to original sources

Fractionation of carrier ampholytes for isoelectric focusing.

A simple method for fractionating synthetic carrier ampholytes is reported, based on the principle of continuous-flow isoelectric focusing in gel-stabilized layers. An 8% ampholyte solution, encompassing the pH range 3-9.5, is separated into 12 fractions in a chamber filled with Sephadex G-100 by a continuous-flow technique. We are thus able to obtain ampholytes of narrow pH range, encompassing approximately 2 pH units, whose resolving power is comparable with that obtained with commercial Ampholine covering similar pH ranges.

Animals↗

Continuous determination of the oxygen dissociation curve for whole blood.

We report here the development of a new method that allows continuous determination of the oxygen dissociation curve for microsamples (600 mul) of whole blood under conditions of pH, pCO2, methemoglobin concentration, and 2,3-diphosphoglycerate content closely approaching those found in the circulatory system. The method consists of gradually oxygenating a blood sample by adding H2O2 in the presence of catalase (EC 1.11.1.6), to produce the reaction H2O2 leads to H2O + 1/2 O2. Because the total oxygen content of blood can be derived from the known rate of H202 addition and the pO2 is determined in the liquid phase by an oxygen electrode, the two functions (total O2 content) and (% oxygen saturation) vs. pO2 are simple to calculate. pCO2 and pH are controlled by adding base simultaneously with the gradual oxygenation of blood. The method described thus avoids the direct measurement of oxygen saturation of whole blood.

Autoanalysis↗

Oxygen affinity and electrolyte distribution of human blood: changes induced by propranolol.

Propranolol causes a massive leakage of potassium ions from red cells, which results in an alteration of the Gibbs-Donnan equilibrium across the red cell membrane. According to such a mechanism, the presence of propranolol significantly increases the hydrogen ion activity of the interior of the red cell, causing a decreased oxygen affinity of hemoglobin according to the classical Bohr effect. No release of 2,3-diphosphoglycerate which may be bound to the membrane is thus necessary to explain the effect of propranolol on the oxygen dissociation curve of blood.

Diphosphoglyceric Acids↗

An integrated system for the automation of the clinical chemistry laboratory.

A user programmable microcomputer-based integrated system for automatic analysis in the clinical chemistry laboratory is presented. Friendly user-instrument interaction helps the operator when defining tests and analytical conditions or entering sample data and test requests. Quality control data are retained for the automatic production of various statistical lists and graphs. Routine operator intervention is limited to reagent preparation, sample loading onto the autosampler plate, definition of the tests to be performed on each of the samples and data validation before the generation of reports. Finally, connection with an existing laboratory management system is provided by means of a standard serial interface.

Automation↗

Simplified computerization of data-base for diabetic patients.

A computerized data-base for the management of the out-patient clinic for diabetes and of the hospital diabetic patients has been developed by means of low cost commercial microcomputer. The program is able to supply lists of sets of patients chosen from user-defined characteristics. The system also allows the selected listin of recall letters for periodic examinations, the printing of registers for medical and administrative use and for statistical analysis. The system is easy to learn and easy to use. The operator-computer interaction is colloquial through the use of a video-terminal, permitting the use by nominally-trained staff.

Computers↗