PubMed Health⌕ Search

Biomedical subjects

V Stolc

Publications and source records attributed to V Stolc.

At least 19 recordsLinked to original sources
PubMed1991

Down's syndrome and mixed acute leukemia in infants.

The routine use of panels of monoclonal antibodies has been complementary to the French-American-British (FAB) leukemia classification, and has unmasked the occurrence of mixed acute leukemia (myeloid-lymphoid). It is widely accepted that children with Down's syndrome (DS) have a high incidence of acute leukemia. There is an extensive body of literature emphasizing the cytogenetic findings in these children. However, information as to the immunophenotype is often limited to the lymphoid surface determinants. The authors report two children with DS whose leukemic blasts were studied with a panel of 17 monoclonal antibodies (myeloid, lymphoid, and megakaryocytic) by flow cytometric examination and were classified as biphenotypic acute leukemia. The blast population coexpressed myeloid and T-cell surface markers. The lymphoid origin was ruled out on the basis of negative terminal deoxynucleotidyl transferase and molecular analysis demonstrating germline configuration for the JH and beta TCR genes.

Antibodies, Monoclonal↗
PubMed1991

Detection of rearrangement of immunoglobulin heavy chain and T-cell receptor beta chain in leukemic cells by restricted polymerase chain reaction.

Rearrangement of the immunoglobulin heavy chain and of the T-cell receptor beta subunit was analyzed by using restricted polymerase chain reaction (PCR). To differentiate between the germline configuration and the rearranged genome in a DNA sample extracted from lymphocytes, we compared the ratio of the amplified products. The intensity of amplification of the intron region (JHF) upstream of the first joining region was compared to the intensity of joining region 6 of the immunoglobulin heavy chain. The number of the amplification cycles in the PCR was designated in such a way that the ratio of JHF/JH6 was less than one in the rearranged configuration. As the concentration of clonal B-lymphocytes with the rearranged genome in the sample increased the amplification of the JHF intron proportionally decreased. We used the same approach for the two constant regions of the T-cell receptor beta chain. As one of the intron regions of the constant sequence became depleted by rearrangement so the amplification of the particular region decreased. Therefore, the absence or decreased concentration of a particular product of amplification indicated deletion and thus rearrangement of the genome in the leukemic B- or T-lymphocytes. The threshold of detection of cells with the rearranged genome on a photograph of agarose gel loaded with the particular amplified regions and staining with the ethidium bromide is less than 10% by densitometric tracing and 25-50% by visual evaluation. This novel approach allows the detection of the rearranged DNA sequences in a 2 day span. Hence, it can serve as a diagnostic tool for the identification of clonal expansion of lymphocytes in acute leukemias and lymphomas in particular and for the detection of deleted genomic regions in general.

Amino Acid Sequence↗
PubMed1991

Polymorphism of cyclic 3',5'-adenosine monophosphate stimulation in rat erythrocytes.

Significant differences were found in the cyclic 3',5'-adenosine monophosphate (cAMP) levels in (-)-isoproterenol-stimulated rat erythrocytes. The BN strain had the highest level (13.1 +/- 1.29 pmol cAMP/10 mg Hb) and the LEW strain had the lowest cAMP level (3.29 +/- 1.76 pmol cAMP/10 mg Hb) in the erythrocytes. The high levels were inherited in three intercrosses in a dominant fashion. The results of the backcross breeding suggested diallelic inheritance. However, the polygenic effect was not ruled out.

1-Methyl-3-isobutylxanthine↗
PubMed1989

Immunophenotyping in the classification of acute leukemia in adults. Interpretation of multiple lineage reactivity.

Fifty-nine adult patients with acute leukemia were classified using a combination of the French-American-British (FAB) criteria and characterization by immunophenotyping using flow cytometric study. The authors identified 51 patients with acute myeloblastic leukemia and eight with acute lymphoblastic leukemia. This procedure permitted lineage assignment in leukemias that otherwise might have been unclassifiable. In addition, the authors demonstrated that the leukemic blasts of 29% of patients with myeloblastic disease exhibited one or more T-cell antigens on their surface. The use of immunophenotyping has greatly enhanced the authors' ability to correctly identify the lineage of acute leukemias. The data, however, must be interpreted with caution with respect to diagnosing acute mixed lineage leukemias and must be integrated with the morphologic and cytochemical evaluation of traditional classification schemes. The possible significance of T-cell markers in myeloblastic leukemia is discussed.

Adult↗
PubMed1989

Microgranular promyelocytic leukemia: a multiparameter examination.

Six cases of microgranular variant acute promyelocytic leukemia (M3v) were studied by use of a multiparameter approach including morphology, cytochemistry, flow cytochemistry, flow cytometry, cytogenetics, and gene rearrangement. Three of six cases demonstrated both myeloid and monocytoid associated surface markers by flow cytometry. One of six cases had strong alpha-naphthyl-butyrate esterase (alpha-NBE) activity in addition to myeloperoxidase activity. There was no correlation between percentage of positive monocytoid surface markers and intensity of cytoplasmic alpha-NBE activity. Four of six cases also had a T-cell-associated surface antigen. Further studies indicated that the T-cell markers appeared to be on the promyelocytes and that the T-B receptor gene was not rearranged. Similarly, cytogenetics studies indicated only one clonal abnormality t(15q+; 17q-). Whether these cases represent true "lineage infidelity" remains to be answered. Future important studies are needed on normal hematopoietic progenitor cells at early stages of development and childhood to study lineage-specific characteristics and to determine whether co-expression normally exists during early development.

Adult↗
PubMed1989

Regulation of total leukocyte, neutrophil and lymphocyte concentrations in human blood by major effectors.

Commingling analysis of total leukocyte, neutrophil and lymphocyte concentrations in human blood suggested the effect of major regulatory factors affecting each type of white blood cells. Our results showed two distributions for the total leukocyte and lymphocyte concentrations. The values of the low and high phenotypes were 5.8 and 8.4 x 10(9)/l of total leukocytes and 2.0 and 4.6 x 10(9)/l of total lymphocytes. On the other hand, the neutrophil concentration in blood is probably regulated by equally penetrant factors. The means of the three phenotypes were 2.6, 4.2 and 6.5 x 10(9)/l. The evidence of two or three phenotypes, although consistent with the effect of a single-factor hypothesis (genetic or environmental), must be confirmed by segregation analysis of families.

Adolescent↗
PubMed1987

A polymorphic variant of the lactate dehydrogenase B subunit in the rat.

A new electrophoretic variant of the lactate dehydrogenase B subunit was found in the erythrocytes of the COP strain of the rat. The location of the band after the electrophoresis suggested a product of the structural gene for the B subunit. Two alleles that regulated the high amount (Ldh-2a) or the low amount (Ldh-2b) of the B subunit were found and segregated in Mendelian fashion. The activity was regulated by the closely linked (less than 1 cM) regulatory gene Ldr-1.

Alleles↗
PubMed1987

Interleukin-2 receptor levels are increased in blood of heart transplant patients during infections.

Increased levels of soluble interleukin-2 (IL-2) receptor were found in plasma of six patients after the heart transplantation. The levels peaked the first week after transplantation and then gradually decreased to normal levels. The moderate episodes of heart transplant rejection did not affect the IL-2 receptor levels in comparison to transplant recipients without the rejection episodes. However, the transplant patients with pneumonia had the IL-2 receptor levels ten times higher than healthy controls. Hence, the IL-2 receptor levels in plasma might be a valuable indicator of the dynamics of the acute infection in heart transplant recipients.

Fever↗
PubMed1979

Inhibition of 14C-labeled amino acid incorporation into protein by particles and surface-active agents in human granulocytes.

Contact of human polymorphonuclear leukocytes with latex or zymosan particles resulted in inhibition of incorporation of 14C-labeled amino acids into protein in the phagocytosing cells. The surface-active agents, concanavalin A and digitonin, exerted the same inhibitory activity on 14C-labeled amino acid incorporation into protein in human granulocytes. The inhibition of 14C label incorporation was dose dependent and the half-maximal effect per 10(7) cells was found at 0.8 mg of latex (0.79 micrometer in diameter), 0.25 mg of serum-coated zymosan and 35 microgram of digitonin/ml of the incubation medium. Amino acid transport (14C-labeled amino acids or amino[14C]isobutyrate) was the same in the resting and phagocytosing granulocytes. These results suggest that the incorporation of 14C-labeled amino acids into protein in human granulocytes is in some way connected to alteration in the cell plasma membrane.

Amino Acids↗
PubMed1979

Characterization of iodoproteins secreted by phagocytosing human polymorphonuclear leukocytes.

Several proteins, glycoproteins, and iodoproteins are secreted from human polymorphonuclear leukocytes during phagocytosis of inert latex particles. The amount of 125I-labeled proteins increases during 10 to 60 min of incubation. The 125I-iodoproteins secreted into the incubation medium during the phagocytosis were first separated on Sephadex G-150 column and then characterized by column chromatography on Sepharose 4B, Sephadex G-200, and G-100. Three 125I-iodoproteins were found with the molecular weights of 580,000, 100,000, and 22,000. The molecular mass of 15 protein subunits calculated after sodium dodecyl sulfate-polyacrylamide gel electrophoresis ranged from 11,000 to 86,000 daltons. Four of the protein subunits were labeled with 125I. Their molecular weights were 63,000 to 69,000, 44,000 to 49,000, 22,000, and 11,000. In addition to iodoproteins, several 125I-labeled peptides and compounds were found by column chromatography on Bio-Gel P-2 and P-10. The 125I-iodoproteins are not secreted from resting or boiled granulocytes, and their production is 92 to 98% inhibited by 1 mM KCN or 1 mM sodium azide. The double-labeling technique with [125I]- and [131I]-iodine suggests that the iodoproteins formed in the phagocytosing granulocytes or secreted into the incubation medium are not identical.

Granulocytes↗
PubMed1979

Serum ferritin and bone marrow iron stores. I. Correlation with absence of iron in biopsy specimens.

Serum iron, total iron-binding capacity, and percentage saturation of transferrin have classically been used to demonstrate a hypoferremic state; however, these tests may not discriminate between depleted iron stores and conditions associated with defective reticuloendothelial release of iron. Estimation of stainable iron in the bone marrow biopsy specimen is then the most practical way to assess body iron stores. With the availability of a radioimmunoassay procedure for serum ferritin, we undertook a prospective study to determine whether serum ferritin concentrations might replace assessment of the marrow biopsy iron stores as an indicator of hypoferremia. Iron stores were absent from bone marrow biopsy specimens from 104 patients. A good correlation between low serum ferritin levels and absence of iron stores in biopsy specimens was found for 91 patients (87.5%). Thirteen (12.5%) had normal serum ferritin concentrations with absence of biopsy iron. These individuals had hematopoietic malignancies or active hepatic disease, or were receiving iron therapy. In this group, a bone marrow biopsy would still be necessary for evaluation of a hypoferremic state, even though the serum ferritin concentration might be normal.

Adult↗
PubMed1979

Effect of colchicine on PGE1 stimulation of cAMP1 formation in human lymphoblastoid and normal lymphocytes.

PGE1 increased cAMP level in human lymphoblastoid cells (RPMI 1788) after 5-60 min of incubation at 37 degrees C. A gradual decrease of cAMP concentration was found at the later time intervals. Colchicine significantly potentiated the stimulatory effect of PGE1, although it did not have any effect on cAMP level in control lymphoblastoid cells. The maximal effect of colchicine on PGE1 stimulation of cAMP formation was at the 0.1-1.0 microM level. Human lymphocytes also responded with increased cAMP formation to colchicine addition. In contrast, no stimulatory effect of colchicine was found in human granulocytes.

Cell Line↗
PubMed1977

Mechanism of regulation of adenylate cyclase activity in human polymorphonuclear leukocytes by calcium, guanosyl nucleotides, and positive effectors.

This study presents the results of a kinetic investigation of adenylate cyclase in human polymorphonuclear leukocytes. In the presence of a saturating concentration of substrate (1 mM), the basal activity was increased severalfold by increasing Mg2+ from 1 to 25 mM. A Hill coefficient of 1.9 was obtained for Mg2+ or ATP. The data suggest cooperative interactions between the substrate binding sites in the neutrophil adenylate cyclase complex. It has been observed that guanyl-5'-yl imidodiphosphate (Gpp(NH)p) (S0.5 = 10 MUM) significantly increased and Ca2+ (S0.5 = 0.5 MM) significantly decreased only the Vmax without affecting the Hill coefficient or S0.5 for ATP. The Hill coefficients for Ca2+ or Gpp(NH)p were 0.9 and 0.8, respectively. The Hill coefficient for Ca2+ was not changed by the increased Gpp(NH)p concentrations. It appears that neutrophil adenylate cyclase has distinct binding sites for Gpp(NH)p and Ca2+, one for each compond. The binding of ligands is not changed by the other effectors and the action is directed only toward the Vmax of the enzyme. The stimulatory action of positive effectors (prostaglandin E1, isoproterenol, histamine) was enhanced by Gpp(NH)p and depressed by Ca2+. No preferential stimulation by Gpp(NH)p nor inhibition by Ca2+ of the action of the positive effectors has been found. The data suggests that only one type of catalytic subunit responds to the action of several positive effectors. Extracellular Gpp(NH)p or Ca2+ do not affect the cyclic adenosine 3':5'-monophosphate (cAMP) level in whole neutrophils and the effect of positive effectors on cAMP production is also not significantly changed by 5 mM Ca2+ or 0.1 mM Gpp(NH)p. Ionophore A23187 in the presence of 5 mM Ca2+ enhances Ca2+ entry into cells and decreases the basal cAMP formation. It appears that Gpp(NH)p or Ca2+ act only at the intracellular site of the adenylate cyclase complex.

Adenosine Triphosphate↗