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Biomedical subjects

L C Cerny

Publications and source records attributed to L C Cerny.

14 recordsLinked to original sources
PubMed1992

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↗
PubMed1992

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↗
PubMed1990

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↗
PubMed1988

The erythrocyte sedimentation rates: some model experiments.

In order to obtain a better understanding of the erythrocyte sedimentation rate (ESR), several models are presented. The first directs attention to the importance of geometrical models to represent the structure of mixtures. Here it is our intention to understand the effect of the structure on the packing of red blood cells. In this part of the study, "Cheerios" (trademark General Mills) are used as a macroscopic model. It is interesting that a random sampling of "Cheerios" has the same volume distribution curve that is found for erythrocytes with a Coulter Sizing Apparatus. In order to examine the effect of rouleaux formation, the "Cheerios" are stacked one on top of another and then glued. Rouleaux of 2,3,4,5, 7 and 10 discs were used. In order to examine a more realistic biological model, the experiments of Dintenfass were used. These investigations were performed in a split-capillary photo viscometer using whole blood from patients with a variety of diseases. The novel part of this research is the fact that the work was performed at 1g and at near zero gravity in the space shuttle "Discovery." The size of the aggregates and/or rouleaux clearly showed a dependence upon the gravity of the experiment. The purpose of this model was to examine the condition of self-similarity and fractal behavior. Calculations are reported which clearly indicate that there is general agreement in the magnitude of the fractal dimension from the "Cheerios" model, the "Discovery" experiment with those determined with the automatic sedimentimeter. The final aspect of this work examines the surface texture of the sedimention tube. A series of tubes were designed with "roughened" interiors. A comparison of the sedimentation rates clearly indicates a more rapid settling in "roughened" tubes than in ones with a smooth interior surface.

Blood Sedimentation↗
PubMed1988

The sedimentation potential and the boycott effect.

The sedimentation potential or the Dorn effect occurs when heavy particles fall in a liquid. An electrode near the bottom of the vessel acquires a potential difference with respect to another identical electrode placed near the upper surface of the solution. The Boycott phenomenon enhances the sedimentation in inclined vessels. In this investigation, fixed erythrocytes at 2-3% concentration were studied. The shapes include discs, oblate spheroids, spheres and spindles. From the sedimentation potentials, the zeta potentials were calculated and compared with those determined by laser Doppler velocity. By using a technique of reduced variables, it is shown that all of the data could be placed on a single curve, combining particle flexibility, shape, concentration and angle of inclination.

Blood Sedimentation↗
PubMed1987

Expression of myosin heavy chain isoforms in regenerating myotubes of innervated and denervated chicken pectoral muscle.

Monoclonal antibodies were prepared to stage-specific chicken pectoral muscle myosin heavy chain isoforms. From comparison of serial sections reacted with these antibodies, the myosin heavy chain isoform composition of individual myofibers was determined in denervated pectoral muscle and in regenerating myotubes that developed following cold injury of normal and denervated muscle. It was found that the neonatal myosin heavy chain reappeared in most myofibers following denervation of the pectoral muscle. Regenerating myotubes in both innervated and denervated muscle expressed all of the myosin heavy chain isoforms which have thus far been characterized in developing pectoral muscle. However, the neonatal and adult myosin heavy chains appeared more rapidly in regenerating myotubes compared to myofibers in developing muscle. While the initial expression of these isoforms in the regenerating areas was similar in innervated and denervated muscles, the neonatal myosin heavy chain did not disappear from noninnervated regenerating fibers. These results indicate that innervation is not required for the appearance of fast myosin heavy chain isoforms, but that the nerve plays some role in the repression of the neonatal myosin heavy chain.

Animals↗
PubMed1986

Contractile activity is required for the expression of neonatal myosin heavy chain in embryonic chick pectoral muscle cultures.

The expression of neonatal myosin heavy chain (MHC) was examined in developing embryonic chicken muscle cultures using a monoclonal antibody (2E9) that has been shown to be specific for that isoform (Bandman, E., 1985, Science (Wash. DC), 227: 780-782). After 1 wk in vitro some myotubes could be stained with the antibody, and the number of cells that reacted with 2E9 increased with time in culture. All myotubes always stained with a second monoclonal antibody that reacted with all MHC isoforms (AG19) or with a third monoclonal antibody that reacted with the embryonic but not the neonatal MHC (EB165). Quantitation by ELISA of an extract from 2-wk cultures demonstrated that the neonatal MHC represented between 10 and 15% of the total myosin. The appearance of the neonatal isoform was inhibited by switching young cultures to medium with a higher [K+] which has been shown to block spontaneous contractions of myotubes in culture. Furthermore, if mature cultures that reacted with the neonatal antibody were placed into high [K+] medium, neonatal MHC disappeared from virtually all myotubes within 3 d. The effect of high [K+] medium was reversible. When cultures maintained in high [K+] medium for 2 wk were placed in standard medium, which permitted the resumption of contractile activity, within 24 h cells began to react with the neonatal specific antibody, and by 72 h many myotubes were strongly positive. Since similar results were also obtained by inhibiting spontaneous contractions with tetrodotoxin, we suggest that the development of contractile activity is not only associated with the maturation of myotubes in culture, but may also be the signal that induces the expression of the neonatal MHC.

Animals↗
PubMed1978

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↗
PubMed1977

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↗