40-year old woman with a solitary cavitary lung lesion.
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Adult↗
Biomedical subjects
D E Williams
Publications and source records attributed to D E Williams.
Effects of flt3 ligand on acute myeloid and lymphocytic leukemic blast cells from children.
A ligand for the flt3 tyrosine kinase receptor (flt3R) has recently been cloned. Forty-three cases of childhood acute myeloid leukemia (AML) and 27 cases of childhood acute lymphocytic leukemia (ALL) were examined by flow cytometric analysis for cell-surface flt3R and proliferative response in vitro to flt3 ligand (flt3L). Flt3R was commonly expressed on the cell surface of leukemic cells from all AML subclasses and B-ALL, but we did not detect cell-surface flt3R on T-ALL. Flt3L alone induced the proliferation of the monocytic AML-M5 cells and some erythroleukemic AML-M6 cells. Some isolated instances of weak proliferative responses were also noted in other AML subclasses. Interleukin-4 (IL-4) alone inhibited the proliferation of a group of AML-M5 cells and, when combined with flt3L, suppressed the proliferative effect of flt3L. In general, B-ALL and T-ALL cells failed to respond to flt3L alone or in the presence of combinations of IL-2, IL-3, or IL-7.
Acute Disease↗
Dietary indole-3-carbinol inhibits FMO activity and the expression of flavin-containing monooxygenase form 1 in rat liver and intestine.
Indole-3-carbinol (I3C), a naturally occurring component of cruciferous vegetables, has been shown to be an effective cancer chemopreventative agent in a number of animal models, and is currently being evaluated in human clinical trials. One proposed mechanism of action for I3C involves binding of I3C acid condensation products (formed in the stomach) to the Ah receptor, with resultant induction of both Phase I and Phase II enzymes. We have previously shown that dietary administration of I3C to male Fischer 344 rats markedly induces hepatic levels of CYP1A1, and to a lesser degree CYP1A2, CYP2B1/2, and CYP3A1/2. We now report that such treatment concurrently inhibits both the activity and expression of flavin-containing monooxygenase (FMO) form 1 in rat liver and intestine. This inhibition demonstrates both a time and dose dependency, resulting in an 8-fold reduction in expression of FMO1 in liver, and almost total ablation of FMO1 in intestinal tissues at the highest dietary I3C levels examined. There are many examples of xenobiotics that are metabolized by both the CYP and FMO monooxygenase systems. In many cases these enzyme systems produce different metabolites, which often have strikingly disparate toxicological and/or therapeutic properties. Therefore, the marked shift in the ratio of FMO/CYP levels in the livers (and other tissues) of rats fed I3C may result in significant alterations in the metabolism, disposition, and toxicity of xenobiotics. Testing for a similar phenomenon in humans would seem advisable before wide-spread administration.
Animals↗
Effect of flt3 ligand on the ex vivo expansion of human CD34+ hematopoietic progenitor cells.
A ligand for the tyrosine kinase receptor flt3/flk-2, referred to here as flt3 ligand (flt3L), was recently cloned. The effect of flt3L on purified human CD34+ progenitor cells was examined. flt3 receptor (flt3R) was detected on the surface of human bone marrow cells that were enriched for CD34 expression. The effects of flt3L and the c-kit ligand Steel factor (SLF) on hematopoietic progenitors were compared in clonal colony assays. Both factors synergized with Pixy321 (interleukin-3 [IL-3]-granulocyte-macrophage colony-stimulating factor fusion protein) to induce granulocytic-monocytic (GM) and high proliferative potential (HPP) colonies and synergized with Pixy321 + erythropoietin (EPO) to induce multipotent granulocytic-erythroid-monocytic-megakaryocytic colonies. Although SLF had a potent effect on colony formation of erythroid restricted progenitor cells (burst-forming unit-erythroid), no effect by flt3L was observed. The addition of flt3L to irradiated long-term marrow cultures seeded with CD34+ cells augmented both total and progenitor cell production. Ex vivo expansion studies with isolated CD34+ bone marrow cells from normal donors showed that flt3L alone supported maintenance of both GM and HPP progenitors for 3 to 4 weeks in vitro. The addition of flt3L to a growth factor combination of IL-1 alpha + IL-3 + IL-6 + EPO resulted in a synergistic effect on progenitor cell expansion comparable to that observed with the addition of SLF to IL-1 alpha + IL-3 + IL-6 + EPO. These data show a function for flt3L in the regulation of both primitive multipotent and lineage-committed hematopoietic progenitor cells.
Antigens, CD34↗
In vivo biologic effects of PIXY321, a synthetic hybrid protein of recombinant human granulocyte-macrophage colony-stimulating factor and interleukin-3 in cancer patients with normal hematopoiesis: a phase I study.
PIXY321 is a novel fusion protein of recombinant human granulocyte-macrophage colony-stimulating factor and interleukin-3 that exhibits biologic effects of both its parent cytokines in vitro and in preclinical studies. To evaluate the clinical safety and hematopoietic effects of this hybrid cytokine, PIXY321 was administered by subcutaneous injection twice daily at doses of 25 to 1,000 micrograms/m2/day over 14 days to 24 patients with sarcoma before chemotherapy as part of a phase I trial. The treatment was associated with significant increases in white blood cell, neutrophil, platelet, and reticulocyte counts (all P < .001). The increase in neutrophil count was dose-related and was seen during treatment with the cytokine, whereas the increase in platelet count was gradual and peaked after the cessation of the cytokine treatment and was not clearly dose related. PIXY321 treatment also increased bone marrow (BM) cellularity and the percentage of BM cells in S phase (P < .001). In addition, there was a significant increase in the number of CD34+ cells and committed and multipotential progenitors in the peripheral blood. The ex vivo expansion capacity of peripheral blood and BM progenitor cells was preserved after the in vivo treatment with PIXY321. The treatment was well tolerated, with the most common side-effect being injection site reactions. The results of this study show the biologic and clinical activity of a genetically engineered fusion molecule of two hematopoietic cytokines in humans with normal hematopoietic function.
Agranulocytosis↗
Quantitation of digoxigenin-labeled DNA hybridized to DNA and RNA slot blots.
Quantitation of message from low-abundance mRNAs and limited availability of tissues requires sensitive methods for probe detection, accurate methods for quantitation of signal, and the ability to strip and reprobe membranes. A random-primed, digoxigenin-labeled probe from cDNA of FMO1, an isoform of the flavin-containing monooxygenase gene family, from rabbit was used in the evaluation and optimization of the Genius system for quantitation of signal from DNA and RNA slot blots. Criteria for optimization were a low signal to noise ratio, a linear increase in density of signal vs nuclei acid concentration of bands on X-ray film, complete stripping of membranes, and reproduction of the initial banding pattern upon rehybridization. A low signal-to-noise ratio was obtained with an aqueous prehybridization/hybridization solution. DNA slot blots were successfully quantitated before and after alkaline stripping from positively charged membranes. RNA slot blots were subject to excessive and uneven loss of RNA from the membranes during stripping procedures. Reliable quantitation for more than one cycle of detection required highly charged nylon membranes, and careful tailoring of RNA fixation methods and alkaline stripping conditions.
Animals↗
c-kit ligand gene expression in normal and sublethally irradiated mice.
The c-kit ligand (KL; Steel factor, mast cell growth factor, stem cell factor) is a hematopoietic factor that has been shown to act as a potent cofactor for hematopoietic growth and differentiation in vitro. The in vivo effects of KL, however, have been variable. To study the hematopoietic role of KL in vivo, we evaluated KL gene expression in both normal mice and mice recovering from myelosuppressive radiation exposure using the reverse transcriptase-polymerase chain reaction (RT-PCR) technique. In a single RNA sample, we found that the RT-PCR technique has high precision (co-efficient of variation, 15.7%). Amplifications of serial 1:2 dilutions of template RNA precisely correlated with starting RNA concentrations at 20 cycles or at 25 cycles, depending on the level of expression. Amplification of individual normal bone marrow and spleen cell RNA showed basal expression in all normal bone marrows but irregular expression in normal spleens. On day 2 after a sublethal 7.75-Gy (0.4 Gy/min) 60Co irradiation, splenic KL gene expression increased approximately 2.5-fold (P = .011), and bone marrow expression increased 15-fold (P = .004). During a 28-day postirradiation recovery period, KL expression increased in bone marrow on days 2 through 7. Splenic expression during the same period was more variable. In conclusion, the KL gene is invariably expressed in normal murine spleens. Postirradiation, recovering bone marrow and spleen both express increased levels of KL mRNA at day 2 and continue to express increased levels for several days postexposure. These data support a role for KL in the endogenous recovery of hematopoiesis after hypoplastic injury.
Animals↗
Developmental regulation of flavin-containing monooxygenase (FMO) isoforms 1 and 2 in pregnant rabbit.
Mammalian flavin-containing monooxygenase (FMO, EC 1.14.13.8) metabolizes a vast number of structurally diverse xenobiotics containing a soft-nucleophile, typically a nitrogen or sulfur. FMO is not inducible by the classical cytochrome P450 (CYP) inducers, such as phenobarbital, polycyclic aromatic hydrocarbons, ethanol or macrolide antibiotics. Evidence does exist from a number of laboratories, however, for developmental and hormonal regulation of FMO. Our laboratory has confirmed previous observations of enhanced FMO activity during mid- and late-gestation in maternal rabbit lung and have demonstrated that this response is due to increased protein and catalytic activity associated with FMO2. The time course of expression of FMO2 during mid- and late-gestation correlates to plasma peaks of progesterone or cortisol. FMO2 also peaks at parturition in maternal kidney, coincident with plasma cortisol levels. FMO2 is induced by s.c. administration of either progesterone or dexamethasone in lung, or by dexamethasone in kidney. Correlation of plasma progesterone or cortisol levels during gestation and postpartum support a role for progesterone, but not cortisol in regulation of FMO2 in maternal rabbit lung. The levels of FMO1 also appear to be increased during mid- and late-gestation in liver. FMO1 in liver may also be regulated during gestation by progesterone or glucocorticoids as administration of these steroids enhanced FMO1 mRNA levels 4-fold.
Animals↗
The anticarcinogen 3,3'-diindolylmethane is an inhibitor of cytochrome P-450.
Dietary indole-3-carbinol inhibits carcinogenesis in rodents and trout. Several mechanisms of inhibition may exist. We reported previously that 3,3'-diindolylmethane, an in vivo derivative of indole-3-carbinol, is a potent noncompetitive inhibitor of trout cytochrome P450 (CYP) 1A-dependent ethoxyresorufin O-deethylase with Ki values in the low micromolar range. We now report a similar potent inhibition by 3,3'-diindolylmethane of rat and human CYP1A1, human CYP1A2, and rat CYP2B1 using various CYP-specific or preferential activity assays. 3,3'-Diindolylmethane also inhibited in vitro CYP-mediated metabolism of the ubiquitous food contaminant and potent hepatocarcinogen, aflatoxin B1. There was no inhibition of cytochrome c reductase. In addition, we found 3,3'-diindolylmethane to be a substrate for rat hepatic microsomal monooxygenase(s) and tentatively identified a monohydroxylated metabolite. These observations indicate that 3,3'-diindolylmethane can inhibit the catalytic activities of a range of CYP isoforms from lower and higher vertebrates in vitro. This broadly based inhibition of CYP-mediated activation of procarcinogens may be an indole-3-carbinol anticarcinogenic mechanism applicable to all species, including humans.
Aflatoxin B1↗
Treatment of a vocal tic by differential reinforcement.
The purpose of this study was to investigate the effectiveness of differential reinforcement of the absence of a chronic vocal tic in a 9-year-old male. This procedure was used after problems in the application of a simplified habit reversal procedure were encountered, and when it became evident that a reinforcement procedure was more acceptable to the patient. Once differential reinforcement was implemented, a substantial decrease (to near zero frequency) in coughing and throat clearing resulted. The reduction of coughing and throat clearing was seen within and outside the treatment session. Treatment effects were maintained after fading the reinforcement and throughout posttreatment (50 weeks).
Awareness↗
Tissue distribution and clearance of tritium-labeled dihydromicrocystin-LR epimers administered to Atlantic salmon via intraperitoneal injection.
The two epimers of [3H]dihydromicrocystin-LR (spec. act. 32.6 microCi/mumole) were synthesized by reduction of microcystin-LR, a cyclic heptapeptide hepatotoxin, with sodium boro[3H]hydride. In Atlantic salmon, following an i.p. injection of the epimers (0.1 mg of toxin/100 g), the toxins were; after 2 hr, concentrated in the liver and pyloric caeca and intestine; after 5 and 22 hr, concentrated in the liver; and after 46 hr concentrated in the liver and kidney. The maximum concentration in the liver, 4.9 +/- 0.5% of the injected dose, was observed at 5 hr. At 46 hr the incorporation of tritium in the liver was 2.4%. The total whole body incorporation of tritium label at 2, 5, 22 and 46 hr was 67.9 +/- 7.3%, 78.4 +/- 3.1%, 54.5 +/- 6.6% and 12.2%, respectively. The per cent levels of incorporation are significantly lower and the clearance rates are significantly higher than those observed in mice. The ratio of relative concentrations of radiolabel observed in the livers and flesh indicates that extremely low levels of microcystin-LR would be present in the flesh of fish afflicted with 'netpen liver disease'. Coupled with further evidence, it is suggested that the consumption of Atlantic salmon suffering from 'netpen liver disease' does not represent a potential human health hazard.
Animals↗
Regulation of hepatic cytochrome P4501A by indole-3-carbinol: transient induction with continuous feeding in rainbow trout.
This study investigated the kinetics of hepatic cytochrome P-4501A (CYP1A) induction in rainbow trout by indole-3-carbinol (I3C), a natural tumour modulator from cruciferous vegetables, and its low pH reaction products 3,3'-diindolylmethane (I33'), 5,6,11,12,17,18-hexahydrocyclononal[1,2-b:4,5-b':7,8-b"]triindo le cyclic trimer (CT), and the unresolved I3C acid reaction mixture (RXM). RXM, CT and I33' were potent inducers of total embryonic CYP1A following direct microinjection, and of fingerling hepatic CYP1A following ip exposure, whereas I3C itself produced only a transient and relatively weak induction. It is also reported for the first time that dietary I3C induced hepatic CYP1A and its associated ethoxyresorufin O-deethylase (EROD) activity in trout but, again, the induction was weak and transient even with continuous I3C feeding. Mechanism studies and mixed exposures with the Ah agonist beta-naphthoflavone indicated that transient induction by I3C was not due to diet ageing, but appears to involve inactivation of the Ah inductive pathway and irreversible inactivation of CYP1A-mediated EROD activity by I3C-derived metabolites. Thus, I3C derivatives exhibit dual capacities for CYP1A induction and inhibition in trout.
Animals↗
Mechanisms of indole-3-carbinol (I3C) anticarcinogenesis: inhibition of aflatoxin B1-DNA adduction and mutagenesis by I3C acid condensation products.
Possible inhibitory mechanisms of indole-3-carbinol (I3C) against aflatoxin B1 (AFB1), a potent hepatocarcinogen, were examined in rainbow trout. In the Salmonella assay using a trout post-mitochondrial activation system, I3C itself was not an antimutagen against AFB1. The study also evaluated: the antimutagenic ability of I3C oligomers; an acid reaction mixture (RXM) of I3C, generated at low pH to simulate I3C products formed under acidic conditions of the stomach; 3,3-diindolylmethane (I33'), the major derivative of I3C found in trout liver; and 5,6,11,12,17,18- hexahydrocyclononal [1,2-b:4,5-b':7,8-b"]triindole , the cyclic trimer of I3C (CT), a derivative of I3C in liver and one of the major components of RXM. Concentrations of 3.5 microM and greater of I33', CT or RXM showed about 80% inhibition compared with the control. Higher concentrations (70 microM) of the various I3C oligomers also inhibited (to a maximum of 55%) mutagenesis of synthetic AFB1-8,9-epoxide added to the Salmonella assay, in the absence of activating enzymes. I33' inhibited total microsome catalysed AFB1-DNA binding in vitro in an apparently non-competitive manner (Kis = 27.6 +/- 9.4 microM, Kii = 37.5 +/- 32.2 microM). These results suggest that the anticarcinogenic effect of I3C against AFB1 in rainbow trout, and perhaps other species, is due in part to inhibition of AFB1 bioactivation enzymes and to scavenging of the activated AFB1-8,9-epoxide.
Aflatoxin B1↗
Induction of hepatic CYP1A by indole-3-carbinol in protection against aflatoxin B1 hepatocarcinogenesis in rainbow trout.
This study examined the significance of hepatic cytochrome P4501A (CYP1A) induction in the inhibition of aflatoxin B1 (AFB1)-DNA adduction by indole-3-carbinol (I3C) in rainbow trout. I3C, fed prior to [3H]AFB1 exposure, provided dose-dependent inhibition of hepatic AFB1-DNA binding, which appeared to vary inversely with hepatic CYP1A-mediated ethoxyresorufin O-deethylase (EROD) activity (r = -0.81, P = 0.051). However, 1000 ppm dietary 13C inhibited AFB1-DNA adduction without detectably inducing CYP1A protein or EROD activity. Dietary I3C was found to inhibit AFB1-DNA adduction by approximately 50%, whether [3H]AFB1 was injected ip 1, 2, 3, 5 or 7 days after the onset of I3C feeding, yet hepatic EROD activity was only transiently induced over this period and was not correlated with AFB1-DNA inhibition. Microsome-catalysed AFB1-DNA binding in vitro did correlate inversely with EROD activity in microsomes from control- and I3C-treated trout (r = -0.955, P = 0.01), but data obtained using microsomes from beta-naphthoflavone-treated trout suggest that this observation may not be indicative of a cause-and-effect relationship. I3C-mediated reduction in covalent binding was not due to I3C derivatives in the microsomal preparation or to reduced CYP protein levels, but may reflect a lower microsomal catalytic capacity for AFB1 epoxidation as a result of enzyme inactivation. In addition, the major I3C derivative found in liver, 3,3'-diindolylmethane, has been shown to be a non-competitive inhibitor of EROD, and of enzymes that catalyse AFB1 epoxidation. These findings indicate little, if any, role for CYP1A induction in the inhibition of AFB1 carcinogenicity in rainbow trout by levels of I3C likely to be encountered in cruciferous vegetables.
Aflatoxin B1↗
Inhibition of in vitro aflatoxin B1-DNA binding in rainbow trout by CYP1A inhibitors: alpha-naphthoflavone, beta-naphthoflavone and trout CYP1A1 peptide antibody.
Rainbow trout cytochrome P450 (CYP)1A detoxifies aflatoxin B1 (AFB1) to aflatoxin M1 (AFM1), whereas CYP2K1 activates AFB1 to AFB1-8,9-epoxide. We report that alpha-naphthoflavone (ANF) and beta-naphthoflavone (BNF) both strongly inhibit CYP1A-mediated ethoxyresorufin O-deethylase (EROD) activity (Ki = 9.1 +/- 0.8 and 7.6 +/- 1.1 nM, respectively). These inhibitors (selective for mammalian CYP1A at low concentrations), as well as rabbit polyclonal antibody to a trout CYP1A1 peptide (residues 277-294), also strongly inhibited trout microsome-catalyzed AFB1-DNA binding and lauric acid (omega-1) hydroxylation in vitro, reactions previously established to be CYP2K1-dependent. ANF at 0.5, 5, 50 and 500 microM inhibited liver microsome-catalyzed AFB1-DNA binding by 22, 58, 84 and 91%, respectively, whereas BNF at the same concentrations inhibited 22, 74, 78 and 81%, respectively. The CYP1A1 peptide and CYP2K1 polyclonal antibodies (10 mg IgG/mg microsomal protein) inhibited AFB1-DNA binding by 84 and 66%, respectively, compared with pre-immune IgG. Lauric acid (omega-1) hydroxylation was inhibited 61% by 5 microM ANF, 69% by 5 microM BNF and 100% by either antibody at 12 mg IgG/mg microsomal protein. These results demonstrate that mammalian CYP1A inhibitors also inhibit trout microsomal AFB1-DNA binding and lauric acid (omega-1) hydroxylation, catalyzed primarily by CYP2K1. In the absence of evidence that trout CYP1A can catalyze AFB1-DNA binding, the results suggest configuration similarities at, or near, the active sites for these two fish enzymes that result in antibody crossreaction and loss of the inhibitor specificity observed with mammalian CYP1A.
Aflatoxin B1↗
Dehydroepiandrosterone is a complete hepatocarcinogen and potent tumor promoter in the absence of peroxisome proliferation in rainbow trout.
Dehydroepiandrosterone (DHEA), fed for 30 weeks to rainbow trout after initiation with the hepatocarcinogen aflatoxin B1 (AFB1), produced a dose-dependent enhancement of carcinogenesis as measured by increased tumor incidence, multiplicity and size. Significant enhancement was observed at 222 p.p.m., which corresponds to a daily dosage one-half that previously administered to humans in clinical trials. DHEA was also capable of acting as a complete carcinogen in this model, producing liver tumors at doses as low as 222-444 p.p.m. Tumors isolated from trout treated with DHEA alone contained mutations in Ki-ras, primarily codon 12[1] G-->A transitions, providing the first suggestive evidence that DHEA could be a genotoxic carcinogen. The carcinogenicity of DHEA in trout is independent of peroxisome proliferation, as measurements of peroxisomal beta-oxidation and catalase activity support previous observations that trout, like humans, are weak responders to peroxisome proliferators.
Aflatoxin B1↗
Biology and potential clinical applications of flt3 ligand.
The flt3 ligand is a member of a small family of growth factors that stimulate the proliferation of hematopoietic cells. Other members of this family include Steel factor (also known as mast cell growth factor, stem cell factor, and kit ligand) and colony-stimulating factor 1. These proteins function by binding to and activating unique tyrosine kinase receptors. Both flt3 ligand and Steel factor stimulate the proliferation of early progenitor or stem cells. Neither of these factors exhibits much biologic activity by itself, but each factor can synergize with a wide range of other colony-stimulating factors and interleukins. One major difference between the two factors appears to be their effect on mast cells, which Steel factor stimulates, but flt3 ligand does not. Although flt3 ligand and Steel factor each act on early hematopoietic cells, differences in their activities suggest that they are not redundant and are both required for normal hematopoiesis. There are a number of clinical settings in which the flt3 ligand may prove quite useful.
Animals↗
The Behavior Problem Inventory: a further replication of its factor structure.
The Behavior Problem Inventory was administered to a random sample of people living in a state school. The scores from all items and from self-injury items only were factor analysed. The three scales of the Behavior Problem Inventory were highly internally consistent. Factor analysis of all the items showed some similarities to previous studies, and factor analysis of the self-injury items showed a very close correspondence to two previous studies. The results are discussed in terms of the design of this instrument, the possible multi-factorial nature of self-injury and future research on the design of measures of assessments of maladaptive behaviours in people with developmental disabilities.
Adolescent↗