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Biomedical subjects

L C Cerny

Publications and source records attributed to L C Cerny.

10 recordsLinked to original sources

A potential blood substitute from a tetronic polyol and a modified hemoglobin.

This investigation reports a new potential blood substitute. An acellular fluid is formed between a Tetronic polyol and a modified hemoglobin. It was possible to stabilize the hemoglobin with glutaric acid. The subsequent reaction with the alcohols of the Tetronic polyol resulted in a useful resuscitative fluid. Exchange transfusion experiments in rats was possible at the 75% replacement level with an excellent survival rate. This was apparently possible because of the effective transport properties of this material. Histological sections of the liver, kidney and lungs showed little or no permanent damage to the organs. The Tetronic polyol - modified hemoglobin complex was not excreted in the urine in contrast to the modified hemoglobin by itself and a solution of unmodified hemoglobin. These preliminary studies indicate that this combination of a polymer and modified hemoglobin has a potential use as a red cell substitute.

Alcohols

Stabilized hemoglobins as acellular resuscitative fluids.

This study reports some recent work dealing with the stabilization of the tetramers of hemoglobin. It is shown that by using a variety of diacids, it is possible to increase the P50 above that of stroma free hemoglobin. In order to lengthen the retention times in the circulatory system, the stabilized hemoglobins were complexed with both hydroxyethyl starch polymers and polyol tetronic polymers. The resulting hemoglobin-polymer compounds were then freeze-dried. It was possible to reconstitute the powder by the addition of physiological saline when needed. The methods presented here appear to be appear to be as effective as using pyridoxal phosphate but at a fraction of the cost.

Animals

Resonance Raman spectroscopy of chemically modified hemoglobins.

Hemoglobin obtained from out-dated human blood was stripped of 2,3-diphosphoglycerate and modified with the crosslinking agents glyoxalic acid, 1,2-cyclohexadione, or fumarate to stabilize the tetramer. The resulting hemoglobins, which show alterations in their oxygen transport capability, have been studied in their oxy, deoxy and fluoro-met forms using resonance Raman spectroscopy with Soret excitation. The resonance Raman spectra of oxy-hemoglobins cross linked with glyoxalic acid and 1,2-cyclohexadione show that these cross linking agents force the heme into a high spin structure. The resonance Raman spectra of the fluoro-met hemoglobins, however, indicate that the same cross linking agents force the heme into a lower spin structure. Absorption spectroscopy and molecular orbital considerations suggest that protein constraints at the sixth ligand of the heme can account for the change in spin state in the glyoxalic acid and 1,2-cyclohexadione cross linked hemoglobins.

Blood Substitutes

Population screening for beta-thalassemia minor. Report of cooperative trials based on two approaches.

In a cooperative intrastate program based upon experience with sickle-cell anemia screening, the authors explored the feasibility of applying hemoglobin electrophoresis for detection of beta-thalassemia gene carriers. Initially, blood samples collected in capillary tubes were analyzed by cellulose acetate electrophoresis with densitometric quantitation of hemoglobin A2 (Hb A2), followed by selective spectrophotometric quantitation. This approach proved insufficiently specific or reproducible. Follow-up hematologic and family studies of presumptive beta-thalassemia gene carriers indicated that coordinate measurement of erythrocytic indices and Hb A2 values would have discriminated a subpopulation with a high incidence of beta-thalassemia trait more specifically. This approach was tested prospectively by the use of 731 venous blood samples collected in a county with a large population of Mediterranean ancestry. Of 31 individuals (4.2%) with presumptive thalassemia trait, 13 returned for a repeat testing, and the initial results for 11 were confirmed. These findings lend support to an empirical screening sequence suggested by Pearson (erythrocytic indices followed by Hb A2 quantitation), but they also indicate that a significant subpopulation of beta-thalassemia gene carriers with limited phenotypic expression may elude detection in any single-pass approach.

Blood Protein Electrophoresis

Quantitative osmotic fragility and disease states: a preliminary study.

The Kalmedic D-3 Fragiligraph was used to obtain both cumulative and derivative osmotic fragility data. Several instrumental modifications and several procedural changes combined to make the data more reproducible and more easily obtained. An analytical expression employing but two parameters was found to give excellent fits for the cumulative data, and when differentiated, reproduced the experimental derivative data equally well. The curve fitting procedure used is given in detail. Data obtained on a limited number of subjects with beta-thalassemia or multiple sclerosis are presented. The interpretation of these data by techniques common to the literature is compared with the procedure developed in this paper.

Hemolysis