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S Lazary

Publications and source records attributed to S Lazary.

At least 55 records · Page 3Linked to original sources
PubMed1987

Rapid data acquisition from a microtiter plate fluorescence reader and applications in kinetic measurements.

Programs written in Applesoft BASIC for the rapid acquisition and evaluation of data from a commercially available microtiter plate fluorescence reader are presented. Using the data acquisition program, the relative fluorescence readings from all 96 wells of the microtiter plate (one read cycle of the fluorescence reader) can be stored in each of up to 90 consecutively numbered files on a single-sided diskette. A simple timer circuit is described which, when used in conjunction with the above program, initiates the fluorescence reading process at preset time intervals, thus making automatic acquisition of data possible. A further program plots the data from consecutive files on the computer monitor and prints a hard copy if required. The feasibility of applying the above system and software to kinetic measurements in enzyme systems is demonstrated using methylumbelliferyl phosphate and an alkaline phosphatase/immunoglobulin conjugate. In addition, its use in following the formation of extracellular hydrogen peroxide by stimulated polymorphonuclear leukocytes using horseradish peroxidase-coupled oxidation of the fluorescent compound 7-hydroxy-6-methoxy-coumarin (scopoletin) is described.

Enzyme-Linked Immunosorbent Assay↗
PubMed1987

Bovine leukocyte phagocytosis and bacteria killing monitored by intracellular acridine orange fluorescence and extracellular fluorescence quenching.

The time course of phagocytosis and intracellular killing of serum-opsonized Escherichia coli K12 and Staphylococcus aureus SG511 by glass-adherent bovine peripheral blood polymorphonuclear leukocytes (PMNLs) and cultured monocytes (macrophages) was monitored by fluorescence microscopy of single cells using the acridine orange (AO)/crystal violet (CV) technique. After interaction of glass-adherent leukocytes (20, 40, 60 min, 37 degrees C) with opsonized bacteria, cells were stained with the fluorescent dye AO. Living bacteria stained green, dead bacteria stained orange. The addition of CV to AO-stained bacteria quenched the fluorescence of extracellular bacteria only. CV does not penetrate living bovine PMNLs which allows the discrimination of ingested (fluorescent) and extracellular (nonfluorescent) bacteria during attachment and phagocytosis of bacteria by adherent PMNLs. We investigated quantitatively phagocytosis and intracellular killing of serum-opsonized bacteria by bovine PMNLs from 22 bulls of 4 different Swiss dairy breeds. Within 60 min maximum uptake (approximately 12 bacteria/PMNL) and killing (approximately 80%) of serum-opsonized Escherichia coli K12 and Staphylococcus aureus SG511 were achieved. The AO/CV technique was also used to quantify the uptake and intracellular killing of serum-opsonized Escherichia coli K12 by cultured monocytes (macrophages). Within 60 min maximum uptake of bacteria (approximately 16/MO) was achieved; approximately 83% of bacteria were killed.

Acridine Orange↗
PubMed1986

Equine leukocyte antigens: relationships with sarcoid tumors and laminitis in two pure breeds.

Frequencies of equine leukocyte antigen distribution were determined by complement-mediated cytotoxicity testing among populations of Thoroughbred and Standardbred horses, including animals affected with equine sarcoid and laminitis. A highly significant association is described between the presence or history of sarcoid lesions in Thoroughbreds and the expression of the major histocompatibility complex (MHC)-encoded antigens, W3 and B1. No association was found between antigenic expression frequencies and laminitis in either breed. These findings suggest that a strong relationship exists between the equine MHC and a predisposition to sarcoid.

Animals↗
PubMed1986

Joint report of the Third International Workshop on Lymphocyte Alloantigens of the Horse, Kennett Square, Pennsylvania, 25-27 April 1984.

The Third International Workshop on Lymphocyte Alloantigens of the Horse was held on 25-27 April 1984 in Kennett Square, Pennsylvania. Twelve laboratories from five countries participated. The principal purpose of this Workshop was to determine the phenotypic and gene frequencies of the 10 equine lymphocyte antigens (ELA) and a non-ELA lymphocyte antigen, ELY-2.1, in several breeds of horse. A total of 86 alloantisera characterized in previous workshops were tested against lymphocytes from 1179 horses. In addition, several experimental antisera were also tested against the same panel of lymphocytes. As a result of analysis of these data, the Workshop recognized two new equine lymphocyte alloantigens: W11 of the ELA system, and ELY-1.1, an antigen not linked to the ELA system.

Animals↗
PubMed1986

Equine leucocyte antigen system. IV. Recombination within the major histocompatibility complex (MHC).

A case of recombination between the putative class I ELA antigen series and the structure(s) governing mixed lymphocyte reactivity in an informative horse family is described. The results of serological typing, 'lysostripping' and mixed lymphocyte culture tests strongly suggest that the recombination took place between two loci and is not intragenic. An alloantigenic membrane structure, provisionally called B1, which does not belong to the known ELA series, was also involved in the cross-over. The B1 antigen resembles the class II gene products of other species in two respects: it is not present on platelets, and alloantiserum with specificity for B1 inhibits the stimulatory effect of B1-carrying cells in mixed lymphocyte cultures. The B1 antigen does not follow the classical distribution, however, being expressed on both B and T lymphocytes. The finding of separate loci for the first series of ELA antigens and the MLR governing structure(s) demonstrates the similarity of the genetic organization of the horse MHC to that in other species.

Animals↗
PubMed1985

The swine histocompatibility system SLA: serological studies in the common Swiss and Danish swine breeds.

Alloantisera were produced in common Swiss and Danish swine breeds by immunization with leucocytes or skin-grafts. Out of the 126 antisera, 66 were chosen for further study based on titrations employing lymphocytes from unrelated pigs typed with French SLA antisera (Vaiman, Chardon & Renard, 1979). The 66 selected antisera and the French reagents defining 26 SLA specificities were used to type lymphocytes from 595 unrelated pigs of the common Swiss and Danish breeds. The reaction-patterns of the French, Swiss and Danish antisera were adequately correlated for the French SLA specificities Nos FJ 2, 3, 6, 7, 8, 9, 11, 14, 19, 20 and 24 and for the haplotypes FJ 15.1.18 and FJ 5.4. In addition, a cluster of correlated Danish and Swiss antisera characterized a new specificity, provisionally designated CPH 31. This specificity was frequent in the Danish Landrace pigs. Using the reagents identified in this report, the segregation of SLA markers was studied. Back-cross families demonstrated segregation of 15 distinct SLA haplotypes of which 14 are common in French Landrace or Large White. Differences were found in haplotype frequencies in both the Swiss and the Danish Landrace and Large White breeds.

Animals↗
PubMed1985

Equine lymphocyte antigens in four major Belgian horse populations. Contribution to serology and antigen distribution.

158 Belgian Saddlebreds, 130 Belgian Trotters, 108 Belgian Draft horses and 92 Shetland ponies have been typed for serologically defined antigens at the ELA and ELY systems. Gene frequencies were estimated in each breed for the internationally established ELA, ELY-1 and ELY-2 alleles as well as for locally assigned additional ELA markers and for subtypes of ELA-W3, W9 and W11. The distribution of ELA alleles was in agreement with the expected Hardy-Weinberg equilibrium for the 4 horse breeds described here. Differences in gene frequencies between these main Belgian horse populations were observed.

Alleles↗
PubMed1985

Equine leucocyte antigens in sarcoid-affected horses.

The distribution of equine leucocyte antigens (ELA) in horses affected by equine sarcoid tumours was determined and compared with unaffected controls. ELA-haplotype W3,B1 occurred more frequently in affected riding horses of Irish, Swiss and French background. The combined data for the three breeds resulted in a chi 2 value of 20.35 (P less than 0.0005 after correction). Simultaneously, ELA-specificity W11 was more frequently found in horses of Irish background, while W5 was found in Swiss and French horses with sarcoids. The combined data for haplotype W3,B1 and/or W5 specificity demonstrated, in the genetically closely-related Swiss and French horses, a highly significant difference in the occurrence of these haplotypes between affected horses and healthy controls (chi 2 = 28.69, P less than 0.00001 after correction). Thus, the results strongly suggest that the predisposition of horses to sarcoid is associated with or linked to the major histocompatibility complex.

Animals↗
PubMed1982

Equine leucocyte antigen system. III. Non-MHC linked alloantigenic system in horses.

A new, non-MHC linked alloantigenic membrane antigen on the equine lymphocytes is described. This antigen was characterized with alloantisera in the two-stage microcytotoxicity test and designated as ELy-1 antigen. The frequency of ELy-1 antigen positive animals in various populations is close to 50%. ELy-1 shows an autosomal, dominant inheritance. Since an allelic antigen (s) could not be demonstrated in family studies, it is assumed that only two alleles ELy-1+ and ELy-1- exist. The ELy-1 antigen in positive animals is expressed on both T and B lymphocytes but it is not present on erythrocytes and thrombocytes. The incidence of ELy-1 antigen positive animals is significantly higher in horse groups suffering from chronic bronchitis or from laminitis, compared to clinically healthy controls.

Animals↗
PubMed1980

Equine leukocyte antigen system. I. Serological studies.

Lymphocytotoxic alloantibodies have been recognized in primiparous mare sera and colostra using the two-step microcytotoxicity test. The antigens detected on the leukocyte membrane do not occur on the erythrocytes. After testing on a cell panel from unrelated horses, absorptions with leukocytes were carried out. The subsequent retesting of the serum reagents on a cell panel including cells from 24 families rendered possible a grouping of preliminary monospecific reagents characterizing 18 antigen specificities on the cell membrane.

Animals↗
PubMed1980

Equine leukocyte antigen system. II. Serological and mixed lymphocyte reactivity studies in families.

Mono- and oligospecific lymphocytotoxic alloantibodies from primiparous mares were tested on cells from horse families of various breeds in the two-step microcytotoxicity assay. The results showed that the detected antigens were inherited co-dominantly and autosomally as simple Mendelian traits. The membrane antigens showed different linkage with one or more other antigens and seem to be coded by a limited number of loci (at least three) from one chromosome. In the families tested one recombinant for the serologically defined antigens was recognized. The mixed leukocyte reactions of cells from horse families compared with the serologically recognized antigens showed that the two systems are inherited with the same chromosome. A homozygote for both antigen systems was recognized in a family.

Alleles↗
PubMed1978

Lymphokines. VI. Factors in human and other heterologous sera inhibiting the migration of guinea pig macrophages.

Different heterologous sera including human, rabbit, bovine and fetal calf serum (FCS) showed a strong inhibiting effect on the migration of guinea pig peritoneal macrophages (GPPM), compared to the migration of GPPM in homologous guinea pig serum. The inhibiting effect of these sera on the migration of horse monocytes on the other hand was much less marked. Fractionation of human and rabbit serum showed the 4 S fraction to be most inhibitory on GPPM migration. The migration inhibiting effect of heterologous sera on GPPM was prevented by addition of homologous (GP) serum, by absorption of the sera by various guinea pig cells, by heating at 56 degrees and by addition of alpha-L-fucose. Human sera were found to be strongly cytotoxic for 51Cr-labelled guinea pig erythrocytes and lymphocytes, but not for horse lymphocytes. Upon absorption with guinea pig erythrocytes, lymphocytes and kidney cells, the cytotoxicity of the human sera was strongly reduced. Accordingly, the role of heterophilic antibodies and/or of heat-labile MIF-like factors in heterologous sera has to be considered in al macrophage migration experiments where heterologous sera are being used. These factors may differ from the heat-stable MIF activity generated upon antigen- or mitogen-induced stimulation of cultured lymphocytes.

Animals↗
PubMed1976

Production of migration inhibitory factor and blast cell transformation by cord blood lymphocytes.

Cord blood lymphocytes from 29 normal infants of 28-41 weeks gestational age were tested for blast cell transformation and migration inhibitory factor (MIF) production. Cultures were stimulated with phytohemagglutinin (PHA) and purified protein derivative of tuberculin (PPD) for transformation; with purified PHA, soluble and insoluble concanavalin A as well as PPD for MIF production. 3H-thymidine incorporation by cord blood and by adult lymphocytes were similar in magnitude after PHA stimulation, but differed significantly after PPD stimulation, with negligible increased incorporation by the former and marked increased incorporation by the adult lymphocytes. With the exception of PPD, the stimulating agents used led to MIF production by cord blood lymphocytes. No dissociation was observed between proliferative response and MIF production. Both functions seem to be fully developed at birth.

Concanavalin A↗
PubMed1976

Lymphokines. II. Use of horse monocytes as indicator cells for human MIF.

Peritoneal exudate macrophages in guinea pigs and peripheral blood monocytes in man are the most readily available cells sensitive to the migration-inhibiting factor(s) (MIF) induced by tuberculin or insoluble concanavalin A in supernatants of stimulated lymphocyte cultures. The scarcity of MIF-sensitive cells is probably the main reason for the unsatisfactory results obtained with direct and indirect MIF tests when using white blood cells as indicator cells. Isolated horse monocytes represent an alternative sensitive source of indicator cells for human MIF assays, whereas guinea pig peritoneal exudate macrophages appear to be less sensitive and to show large individual variations in sensitivity to human MIF. The species specificity of MIF from various origins shows various patterns and is briefly discussed.

Animals↗
PubMed1976

The effect of Leishmania tropica on stimulation of lymphocytes with phytohaemagglutinin.

Cell-mediated immune (CMI) responses are important in the immunity against leishmanial infections. However, infection persists in the presence of CMI for unknown reasons. Evidence is presented that L. tropica and its products are capable of inhibition of the stimulation of lymphocytes by PHA. This inhibition is dose dependent, and not dependent on competition for nutrients in the medium, nor on neutralization of PHA. The inhibition is observed on the lymphocytes of species susceptible to leishmanial infection, and not operative in resistant species. The mechanisms of the lymphocyte suppression are discussed.

Animals↗