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Biomedical subjects

M Stastny

Publications and source records attributed to M Stastny.

14 recordsLinked to original sources
PubMed1991

A chemiluminescent immunoassay for urinary thromboxane B2.

Because of the vasoactive properties of thromboxane A2 and other related prostaglandins, much research has been conducted on drugs which alter their levels. Urinary levels of thromboxane B2 and 2,3-dinor thromboxane B2 (major urinary metabolite of thromboxane B2) are used as an indication of thromboxane production in-vivo. In order to accurately measure urinary TXB2 levels of subjects on investigative drugs which lower TXA2 and subsequently TXB2, a simple and sensitive analytical tool becomes necessary. We have thus developed a non-radioisotopic (chemiluminescent) assay for urinary TXB2. Sensitivity has been demonstrated to 5 pg/ml. The method correlates well with gas chromatography/mass spectrometry (the accepted reference method) even without column chromatographic purification prior to the conduct of the chemiluminescent assay (r = 0.96). In addition, we have demonstrated feasibility for a chemiluminescent assay to measure urinary 2,3-dinor TXB2.

Acridines↗
PubMed1988

Solid-phase radioimmunoassay of human complement fragment C5a.

In this competitive RIA for determining concentrations of human C5a in biological fluids and in buffers, labeled C5a and sample are allowed to compete for binding to a limited amount of goat antibody to human C5a in solution. Free and bound tracer are then separated by a second antibody (rabbit anti-goat IgG) immobilized on paramagnetic particles. Total incubation time for this assay is 70 min. Sensitivity, precision, and analytical recovery of this assay compare well with those of a reference method.

Binding, Competitive↗
PubMed1987

Immunochemiluminometric assay of creatine kinase MB with a monoclonal antibody to the MB isoenzyme.

Previous two-site immunometric assays for creatine kinase (CK; EC 2.7.3.2) MB isoenzyme have been based on formation of a "sandwich" complex involving CK-MB and antibodies that recognize the CK-MM and the CK-BB isoenzymes. Single-incubation model assays of CK-MB with these antibodies were susceptible to interferences by CK-MM and CK-BB. We produced two anti-CK-MB monoclonal antibodies and studied their suitability for two-site assays. Both antibodies were compatible with anti-CK-MM and anti-CK-BB, but not with each other. Using anti-CK-MB as the tracer antibody eliminated the interference by both CK-MM and CK-BB. Labeling anti-CK-MB with acridinium ester and immobilizing anti-CK-BB on paramagnetic particles, we developed a rapid and highly sensitive chemiluminescent/magnetic separation CK-MB assay. As little as 1 microgram of CK-MB per liter was detectable after 10- or 30-min incubation at room temperature, and the standard curve was linear up to 400 micrograms/L. Results for serum samples by the new assay correlated well (r = 0.94) with those by Corning electrophoretic and the Hybritech Tandem-E immunoenzymometric CK-MB methods. Sera containing macro CK-1 or high concentrations of CK-MM and CK-BB did not interfere. The combined advantages of a more-specific antibody, paramagnetic solid phase, and chemiluminescent label endow this two-site CK-MB assay with performance characteristics and ease of use superior to those of previous assays.

Acridines↗
PubMed1979

Stabilized Romanowsky blood stain.

It has been shown that the degradation of thiazine dyes which normally occurs in methanolic solution, as in the case of Romanowsky blood stains, can be prevented by making the solution acidic. In a certain range of acidity, the stain precipitates in the form of monothiazine eosinate, but by making the solution sufficiently acidic, eosin is protonated and the precipitate cannot form. These observations have been used to develop a blood stain which is stable, even at elevated temperatures, for several months. For use the stain is neutralized by a specially formulated fixative solution.

Blood Cells↗
PubMed1977

The analysis of some commercial dyes and Romamowsky stains by high-performance liquid chromatography.

High-performance liquid chromatography has been used to quantitate batch variations in commericial samples of thiazine dyes, thiazine eosinates, and Romanowsky-type blood stains. It has been observed that all the dyes and eosinates examined, only methylene blue chloride and thionin were reasonably free of their methylated, demethylated, or oxidized homologs. Large variations in composition were observed between most of the samples of each type examined. In several instances the labeled compound was a minority species. In one instance a dye was apparently mislabeled. Large compositional variation was found between various batches of Wright and Giemsa stains, whereas significant differences between the thiazine composition of these two stain types were minor. Very little compositional variation was observed between the lots of LARC stain examined. The thiazine composition of Ames stain was similar for the three lots examined. Ames stain, however, was found to contain several components of unknown composition which have been linked to degradation products formed when stains are aged in methanolic solution.

Chromatography, High Pressure Liquid↗
PubMed1977

The degradation of Romanowsky-type blood stains in methanol.

The oxidative demethylation of Romanowsky-type stains in methanol has been examined quantitatively with respect to its effect upon the staining of blood smears. Spectral changes in bound dye, observed through two color filters, have been measured for the nuclei and cytoplasm of segmented neutrophils and monocytes utilizing the LARC automated differential analyzer. Stain decomposition in methanol results in a large loss in staining intensity with little change in color. The loss in intensity has been correlated with the observed spectral changes in the degraded stain. High-performance liquid chromatographic analysis of degraded stain samples has shown the products of methanolic degradation to be different from those obtained in aqueous polychroming reactions. To maintain a stain of defined thiazine dye composition and thus defined staining properties, refrigeration is recommended.

Blood Cells↗
PubMed1976

The analysis of Romanowsky blood stains by high-performance liquid chromatography.

A high-performance liquid chromatographic procedure has been developed for separating and quantitating the components of thiazine dyes and compound blood stains. In terms of speed, quantitation, and component resolution, the assay reported here is superior to other reported chromatographic methods of cationic dye separation. The components present in commercial samples of thiazine dyes and LARCTM stain, a modified Wright-Giemsa stain, have been resolved in 25-40 min on a 5-mum microparticulate silica column using a methanol-water-glycine/acetic acid mobile phase. The mechanism of separation is demonstrated to be based predominantly upon the weak ion-exchange properties of silica.

Blood↗
PubMed1970

Estrogenic induction of ornithine decarboxylase in vivo and in vitro.

Injection of estrogens (17beta-estradiol or diethylstilbestrol) into immature chicks results in a marked (30- to 50-fold) increase in the ornithine decarboxylase activity of oviductal homogenates within a 4-hour period. Similar stimulations were obtained when estrogen was injected into hypophysectomized or castrated rats and the uterus was examined for decarboxylase activity. An elevation of decarboxylase activity was obtained in vitro when oviducts from immature chicks were incubated in the presence of estrogen. These data indicate a direct action of estrogen on oviduct tissue to promote a rapid increase in the activity of a specific enzyme and represent the first example of a completely in vitro enzyme response to estrogen.

Animals↗