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D L Williams

Publications and source records attributed to D L Williams.

At least 217 records · Page 12Linked to original sources
PubMed1990

Abnormalities of the long arm of chromosome 6 in childhood acute lymphoblastic leukemia.

To determine the biologic significance of the structural rearrangements of the long arm of chromosome 6(6q) in acute lymphoblastic leukemia (ALL) at diagnosis, we studied 412 consecutive children whose leukemic cell chromosomes had been completely banded and identified 45 (11%) children with this abnormality. The 45 cases were divided into del(6q) only (n = 11), del(6q) and numerical abnormalities (n = 4), del(6q) and structural abnormalities (n = 23), and 6q translocations (n = 7). The breakpoints of del(6q) were subgrouped: del(6)(q15q21) in 11 cases, del(6) (q13q21) in six, del(6)(q21q23) in four, del(6)(q15) in four, del(6)(q15q23) in three, and other deletions in 10 cases. Notably, all these deletions encompassed the 6q21 band, suggesting that this might be the locus of a recessive tumor suppressor gene, the absence of which contributes to malignant transformation or proliferation. Among the seven children with 6q translocations, a previously unidentified nonrandom translocation, t(6;12)(q21;p13) was noted in two cases with an early pre-B immunophenotype. Clinical features and event-free survival were similar among children with or without 6q abnormalities. Overall, children with 6q abnormalities were less likely than those without the abnormality to have a pre-B immunophenotype (P = .03). T-cell immunophenotypes were equally represented in cases with or without 6q abnormalities. However, all four children with del(6q) and a 12p abnormality had early pre-B ALL and all three children with del(6q) and a 9p abnormality had a T-cell immunophenotype. The lack of specificity for a particular immunophenotype may imply that the gene or genes affected by 6q abnormalities are broadly active in the multistep process of lymphoid leukemogenesis. The relatively high frequency of microscopically visible del(6q) indicates the need for molecular studies to identify cases with submicroscopic deletions.

Child↗
PubMed1990

The 3'-untranslated region of apolipoprotein II mRNA contains two independent domains that bind distinct cytosolic factors.

The 3'-untranslated region of apolipoprotein II (apoII) mRNA contains target sites for mRNA breakdown (Binder, R., Hwang, S.-P. L., Ratnasabapathy, R., and Williams, D. L. (1989) J. Biol. Chem. 264, 16910-16918). Degradation occurs via endonucleolytic cleavage at 5'-AAU-3'/5'-UAA-3' elements in single-stranded loop domains of the 3'-untranslated region. Degradation target sites occur in two clusters that are localized within two larger domains of secondary structure. In this study, gel shift and label transfer assays were used to identify liver cytosolic factors that recognize the 3'-untranslated region of apoII mRNA. The results show preferential binding of cytosolic factors to the 3'-untranslated region as compared to the coding region. UV cross-linking experiments confirmed that cytosolic factors labeled by the 3'-untranslated region are a subset of proteins labeled by the entire mRNA. Two distinct binding domains were identified within the 3'-untranslated region. The upstream domain encompassing nucleotides 400-547 extends from the translation stop codon through the complex stem-loop D structure described previously. This domain labeled primarily a 34-kDa protein in UV cross-linking experiments. The downstream binding domain encompassing nucleotides 568-643 includes another region of secondary structure and terminates within the universal polyadenylation signal. The downstream domain labeled primarily a 60-kDa protein in UV cross-linking experiments. The upstream and downstream binding domains did not compete with each other in gel shift or cross-linking experiments. These results indicate that the 3'-untranslated region can form two independent messenger ribonucleoprotein complexes localized to domains that include target sites for apoII mRNA degradation. We speculate that these messenger ribonucleoprotein complexes may play a role in the degradation of apoII mRNA or in the regulation of this process.

Animals↗
PubMed1990

14q32 translocations are associated with mixed-lineage expression in childhood acute leukemia.

The frequency and characteristics of childhood acute leukemia with a 14q32 translocation [other than the t(8;14)(q24;q32)] were determined in 335 cases of newly diagnosed acute lymphoblastic leukemia (ALL) and 105 cases of acute nonlymphoblastic leukemia (ANLL). Ten children, representing 2.3% of the entire cohort, had this abnormality (1.5% of ALL patients and 4.8% of ANLL patients). By French-American-British (FAB) criteria, 4 cases were classified as L1, 1 as L2, 2 as M1, 1 as M2, and 2 as M5. Remarkably, mixed-lineage expression was found in 6 of these 10 cases, but in only 21 of the other 430 cases without a 14q32 translocation (P less than .001). Leukemic cells from 5 of these 6 cases (4 ANLL, and 1 ALL) coexpressed CD13, a myeloid-associated antigen, and CD2, a T-cell-associated antigen; blasts from the sixth case (ALL) coexpressed CD13 and CD19, a B-lineage-associated antigen. Thus, in addition to the well-described 11q23 translocations and t(9;22), 14q32 translocations also appear to be associated with mixed lineage antigen expression. Break-points of the reciprocal chromosomes from chromosome 14 were identified in five of these cases: 1q23, 6q23-q25, 7p15, 8q11, and 12q13. Of the four mixed-lineage cases that were tested, none showed rearrangement of the immunoglobulin heavy chain (IgH) gene. This suggests that the 14q32 breakpoint does not involve the IgH gene and that an unidentified important gene may reside on 14q32.

Adolescent↗
PubMed1990

Clinical presentation, karyotypic characterization, and treatment outcome of childhood acute lymphoblastic leukemia with a near-haploid or hypodiploid less than 45 line.

Cytogenetic and DNA flow cytometric analyses of leukemic cells from 2,184 children with newly diagnosed acute lymphoblastic leukemia (ALL) identified 27 cases (1.2%) that had a hypodiploid line with fewer than 45 chromosomes per cell. Had cytogenetic techniques been used alone, seven cases would have been missed, compared with five if only flow cytometry had been used. For comparative purposes, the 27 cases were divided into three groups: near-haploid (n = 10), hypodiploid 30-40 (n = 9), and hypodiploid 41-44 (n = 8). Blast cells from patients with near-haploid ALL lacked structural chromosomal abnormalities; showed nonrandom retention of two copies of chromosomes 8, 10, 14, 18, 21, and the sex chromosomes; and had a second leukemic line with exactly twice the number of chromosomes or DNA content. Karyotypic analysis of the hypodiploid 30-40 and hypodiploid 41-44 groups disclosed structural abnormalities in the stemline or sideline of most of the well-banded cases; those in the latter group were similar to findings in cases with 45 chromosomes. As in the near-haploid group, chromosome 21 and the sex chromosomes were preferentially retained in the hypodiploid 30-40 and 41-44 cases. Except for a slight excess of female patients in the near-haploid group and an older age at diagnosis in the hypodiploid 30-40 cases, there were no initial clinical features that distinguished these patients from the general ALL population. Despite intensive treatment and short follow-up, 17 of the 27 patients have relapsed. This study suggests that the poor treatment responsiveness of hypodiploid ALL is not limited to the more than 80% of the patients who have 45 chromosomes per leukemic cell and demonstrates that cytogenetic and flow cytometric analyses are complementary in the evaluation of children with ALL.

Aneuploidy↗
PubMed1990

Heterogeneity of presenting features and their relation to treatment outcome in 120 children with T-cell acute lymphoblastic leukemia.

Presenting features of 120 consecutive children with T-cell acute lymphoblastic leukemia (ALL), representing 15% of all patients diagnosed as having ALL during the study period, were analyzed to determine relationships with treatment outcome. Patients' ages ranged from 1.7 to 18.8 years (median, 10.3 years) and their leukocyte counts from 1.7 to 1,070 x 10(9)/L (median, 100 x 10(9)/L). Central nervous system (CNS) leukemia was present in 12.5% of the cases, a mediastinal mass in 61%, and L2 lymphoblast morphology in 32%. A relatively high proportion of cases, 26%, had normal karyotypes at presentation. Of the cases tested, membrane CD1 expression was found in 38% of cases, CD3 in 33%, CD4 in 50%, CD5 in 94%, CD8 in 55%, and CD10 in 35%. Four presenting features were found to confer an increased risk of treatment failure: age greater than or equal to 15 years, L2 lymphoblast morphology, abnormal karyotype, and membrane CD3 expression. This study illustrates the heterogeneity of presentations of childhood T-cell ALL and suggests that the relative importance of risk factors in ALL differs according to immunophenotype and treatment strategy.

Age Factors↗
PubMed1990

Kupffer cell:hepatocyte cocultures release nitric oxide in response to bacterial endotoxin.

Nitric oxide (NO.) is a short-lived intermediate in a biochemical pathway where L-arginine is converted to L-citrulline and nitrite/nitrate (NO2-/NO3-). This highly reactive molecule is the biologically active component of this inducible pathway in macrophages. Using a rat Kupffer cell:hepatocyte (KC:HC) coculture model, we have previously shown that this combination of cells produces large quantities of both citrulline and NO2-/NO3- if exposed to lipopolysaccharides (LPS) but we did not determine whether nitric oxide was produced or released. We had also shown that this L-arginine metabolism was associated with a profound decrease in total protein synthesis. In these experiments, we show that KC:HC cocultures release nitric oxide into the culture supernatant if exposed to LPS. NO. production by these cells requires L-arginine and is inhibited by NG-mono-methyl-L-arginine. In addition, the time course for NO. release by KC:HC cocultures parallels the previously reported time course for NO2-/NO3- synthesis and the decrease in protein synthesis, supporting the hypothesis that NO. is the reactive nitrogen intermediate of the pathway responsible for this inhibition of protein synthesis. Finally, we show that KC:HC cocultures release more NO. than KC alone in response to LPS, and we propose that the combination of KC and HC acts as a functional unit capable of generating large amounts of NO. from L-arginine in gram-negative sepsis.

Animals↗
PubMed1990

The use of a specific DNA probe and polymerase chain reaction for the detection of Mycobacterium leprae.

A DNA probe encoding approximately 80% of the 18-kDa protein gene of Mycobacterium leprae was isolated and tested for specificity by assessing hybridization of the probe to genomic DNA from taxonomically related and unrelated DNA samples. The 360-base-pair (bp) probe was specific for M. leprae DNA and did not hybridize with genomic DNA from 18 species of bacteria nor with DNA from human, murine, and armadillo sources. Oligonucleotide primers were synthesized corresponding to the 5' and 3' ends of the 360-bp fragment to yield a fragment of similar size on amplification of M. leprae DNA by the polymerase chain reaction (PCR). A simple procedure for DNA extraction from M. leprae-infected tissues was developed that provided suitable template DNA for amplification. The PCR test was specific for M. leprae DNA from human and murine sources and detected M. leprae DNA in biopsies from leprosy patients and from control and uninfected human skin biopsy preparations seeded with as few as 100 M. leprae.

Animals↗
PubMed1990

Geographically distinct isolates of Mycobacterium leprae exhibit no genotypic diversity by restriction fragment-length polymorphism analysis.

Differentiation of microorganisms for taxonomic purposes is based primarily on phenotypic characteristics, which are the direct or cumulative result of gene expression. Since expression of phenotypic characteristics usually relies on in vitro growth of a microorganism, non-cultivable organisms, such as Mycobacterium leprae, present major problems for the identification of potential variants based on phenotypic similarities or differences between individual isolates. We have employed the use of restriction fragment-length polymorphism (RFLP) analysis of chromosomal DNA of M. leprae isolates, including human isolates from geographically distinct regions of the world and isolates from a Sooty Mangabey monkey and an armadillo, to assess the relatedness among these isolates. Restriction endonuclease (EcoRI, BstEII, PstI, and PvuI) digests of chromosomal DNA were analysed using DNA probes encoding all or part of the 12 kD, 18 kD, 28 kD, 65 kD and 70 kD proteins of M. leprae as well as a probe containing an M. leprae-specific sequence repeated up to 20 times in the M. leprae chromosome. Comparison of the resulting autoradiographs showed that the RFLP patterns were all identical, indicating that these isolates contained no polymorphism with respect to the restriction endonuclease sites analysed. In addition, RFLP patterns of two separate human M. leprae isolates remained unchanged after three cycles of experimental infection in the armadillo model. These results indicated that the M. leprae isolates tested in this study were indistinguishable at the genotypic level, strongly suggesting homogeneity among members of this species.

Animals↗
PubMed1990

Cytogenetics of pre-B-cell acute lymphoblastic leukemia with emphasis on prognostic implications of the t(1;19).

In earlier studies of the cytogenetic characteristics of leukemic lymphoblasts from children with pre-B-cell acute lymphoblastic leukemia (ALL), we concluded that certain chromosomal abnormalities explain, in part, the increased presence of high-risk features at diagnosis and the less favorable response to therapy among patients with this immunologic subclass of ALL. With extended follow-up and a larger patient population, we have further evaluated the biologic and clinical aspects of pre-B leukemia. Of 686 cases of ALL with adequate immunophenotyping, 150 were classified as pre-B cell. Seventy-seven (69%) of the 112 pre-B cases with fully banded karyotypes had a translocation. The t(1;19) accounted for 28 (25%) of these pre-B cases and 31 (6.5%) of all 480 consecutively banded ALL cases. Three (2.6%) of the pre-B cases had a novel dicentric (7;9)(p1?3;p11) translocation. A t(9;22)(q34;q11) and a t(4;11)(q21;q23) were observed in seven (6%) and three (2.6%) of the cases, respectively. Within the pre-B subgroup, comparison of t(1;19) cases (n = 28) with those having other translocations (n = 49) or no identifiable translocations (n = 35) indicated that higher leukocyte counts (P = .002), absence of DNA indexes greater than 1.16 (P = .02), higher serum lactate dehydrogenase levels (P less than .0001), and a higher frequency of nonwhite race (P = .006) were significantly related to the t(1;19). Both the t(1;19) and other chromosomal translocations were associated with an adverse prognosis in the subset of patients treated from 1979 to 1984 (Total Therapy study X). In a more recent and more intensive chemotherapy program (Total Therapy study XI), neither the t(1;19) nor other chromosomal translocations has conferred an inferior outcome, suggesting that effective treatment can offset the negative impact of chromosomal rearrangements in cases of childhood pre-B ALL.

Child↗
PubMed1990

Expression of endogenous and transfected apolipoprotein II and vitellogenin II genes in an estrogen responsive chicken liver cell line.

A recently described chicken liver cell line, LMH, was characterized to evaluate responsiveness to estrogen. Expression of the endogenous apolipoprotein (apo) II gene was induced by 17 beta-estradiol when LMH cells were cultured with chicken serum. The response was low and yielded apoll mRNA at only 0.3% of the level seen in estrogenized rooster liver. Higher levels of apoll mRNA were achieved when LMH cells were transiently transfected with an expression plasmid for estrogen receptor. A transfected apoll gene was strongly expressed only when cotransfected with receptor. Expression of the endogenous vitellogenin (VTG) II gene was not detected. However, when cotransfected with a receptor expression plasmid, VTG II reporter plasmids were expressed in LMH cells in response to 17 beta-estradiol. These results suggest that estrogen responsiveness of LMH cells is limited by the availability of functional receptor. Low levels of estrogen receptor mRNA were detected in LMH cells, and receptor binding sites and mRNA were greatly increased following transient transfection with a receptor expression plasmid. Using this transient transfection protocol, several VTG II reporter plasmids were compared in LMH cells and chick embryo fibroblasts. A plasmid containing VTG II estrogen response elements linked to a heterologous promoter was regulated by estrogen in both cell types. In contrast, reporter plasmids containing the VTG II promoter were regulated by estrogen in LMH cells but were not expressed at all in chick embryo fibroblasts. These results suggest that regulation of the VTG II gene involves cell type-specific elements in addition to estrogen response elements.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Imaging and treatment of B-cell lymphoma.

Ten patients with non-Hodgkin's lymphoma have been evaluated as candidates for experimental radioimmunotherapy and five of those patients have been treated with a single high dose of iodine-131-(131I) labeled anti-pan B-cell antibodies. The evaluation protocol involved collecting biodistribution data by quantitation of gamma camera images and by tumor biopsy from trace labeled doses of antibody, to estimate the relative radiation dose delivered to normal organs and tumor sites. Each patient received up to three escalating mass doses (0.5 mg/kg, 2.5 mg/kg, and 10.0 mg/kg) of radioiodinated antibody for determination of the antibody amount that yielded the most favorable biodistribution for treatment. The millicuries of 131I-labeled to the optimal antibody dose for therapy was selected to deliver 1,000 rads (three patients) or 1,500 rads (two patients) to normal uninvolved organs. Because severe bone marrow toxicity was expected, all patients had their bone marrow cryopreserved prior to entry into the study. This report details the methods and results of quantitative imaging, biodistribution data collection, and absorbed radiation dose estimation in patients with lymphoma receiving high level radioimmunotherapy with 131I-labeled antibodies.

Antibodies, Monoclonal↗
PubMed1989

Kaempferol inhibits myosin light chain kinase.

Kaempferol, 3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one, was found to inhibit bovine aorta myosin light chain kinase with a Ki of 0.3-0.5 microM. It was found to be competitive with ATP and non-competitive with isolated myosin light chains. The specificity of this inhibitor was studied relative to protein kinase C and cAMP dependent protein kinase (IC50 = 15 microM and 150 microM, respectively). It appears not to interact strongly with calmodulin binding proteins, such as Ca2+-calmodulin dependent phosphodiesterase (IC50 = 45 microM), and had little effect on actin-activated myosin subfragment-1 ATPase activity (IC50 greater than 100 microM) or smooth muscle phosphatase activities (IC50 greater than 100 microM).

Animals↗
PubMed1989

Degradation of apolipoprotein II mRNA occurs via endonucleolytic cleavage at 5'-AAU-3'/5'-UAA-3' elements in single-stranded loop domains of the 3'-noncoding region.

Degradation intermediates of the estrogen-regulated apolipoprotein (apo) II mRNA were identified by S1 nuclease mapping and primer extension analysis. S1 mapping of poly(A)-RNA detected a series of mRNAs truncated at specific sites in the 3'-noncoding region. Many of these sites were also detected by primer extension analysis indicating that truncated molecules resulted from endonucleolytic cleavage in the 3'-noncoding region. Identical cleavage sites were seen with RNA from estrogen-treated animals or from animals withdrawn from hormone under conditions where apoII mRNA degraded in the slow (t1/2 = 13 h) or rapid (t1/2 = 1.5 h) decay mode. No differences were seen in poly(A) tail length or heterogeneity among these conditions. These results indicate that the estrogen-induced alteration in apoII mRNA turnover does not involve a new pathway of degradation, but, more likely, involves an increased targeting of the mRNA for degradation by a preexisting pathway. These data are consistent with a mechanism in which the initial step in apoII mRNA degradation is an endonucleolytic cleavage in the 3'-noncoding region without prior removal of the poly(A) tail. The endonucleolytic cleavage sites occurred predominantly at 5'-AAU-3' or 5'-UAA-3' trinucleotides found in single-stranded domains in a secondary structure model of the naked mRNA (Hwang, S-P. L., Eisenberg, M., Binder, R., Shelness, G. S., and Williams, D. L. (1989) J. Biol. Chem. 264, 8410-8418). The structure of the 3'-noncoding region in polyribosomal messenger ribonucleoprotein was examined by titrations of liver homogenates with dimethyl sulfate and cobra venom RNase. The results suggest that the typical cleavage site is a 5'-AAU-3' or 5'-UAA-3' trinucleotide in an accessible single-stranded loop domain. Single-stranded domains alone or accessible domains alone are not sufficient for cleavage. Similarly, 5'-AAU-3' or 5'-UAA-3' trinucleotides alone are not sufficient for cleavage. Localization of these trinucleotides to accessible single-stranded domains in the polyribosomal messenger ribonucleoprotein may provide the specificity for cleavage during targeted degradation.

Animals↗
PubMed1989

Cytogenetics of childhood acute nonlymphocytic leukemia.

Interest in more precise subclassification of the acute leukemias by cytogenetic criteria led us to identify and characterize the full range of chromosomal abnormalities in 121 children with de novo acute nonlymphocytic leukemia (ANLL). Only 21% of the cases had normal karyotypes; 62% had consistent or recurrent alterations, most commonly inv(16) or del(16), t(8;21), t(15;17), t(9;11), t(11;V) or del(11), and -7 or 7q-; and 17% had miscellaneous, apparently random, clonal abnormalities. Statistically significant associations between chromosomal abnormalities and the morphologic/cytochemical subtypes of ANLL, defined by criteria of the French-American-British (FAB) cooperative group were demonstrated for the t(8;21) in M1 and M2 leukemia, t(15;17) in M3, t(9;11) in M5, and translocations involving 11q23 other than t(9;11) [t(11;V)] or del(11q) in M4 and M5. The chromosome 16 inversion was not restricted to the M4 subtype, as is generally reported, and was not uniformly associated with increased and/or abnormal marrow eosinophils. None of these 121 cases were characterized by the Philadelphia chromosome, nor did any have the t(6;9), t(16;16), or inv(3), which have been noted previously in this disease. In addition to confirming several recognized correlations between recurrent structural chromosome abnormalities and FAB subtypes, this study identified novel abnormalities that have not been reported by others. It also disclosed an unusual heterogeneity of chromosome 16 abnormalities with respect to their distribution among FAB subtypes, their association with marrow eosinophilia, and their participation with other chromosomes in translocations.

Child↗