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Biomedical subjects

D M Miller

Publications and source records attributed to D M Miller.

At least 199 records · Page 11Linked to original sources
PubMed1985

Evidence for two isozymes of leukocyte alkaline phosphatase in leukemic leukocytes.

Leukocyte alkaline phosphatase (LAP) is a granulocyte enzyme whose level of expression is markedly altered in various disease states. We have characterized LAP from normal cells and leukemic cells with a high level of LAP activity in order to determine whether increased enzyme levels are caused by increased levels of the same enzyme or induction of a different alkaline phosphatase. Leukocyte alkaline phosphatase was purified from normal granulocytes and from leukemic cells of a patient with chronic granulocytic leukemia (CGL) in blast phase with an elevated LAP level. LAP was partially purified utilizing diethylaminoethyl (DEAE)-cellulose ion exchange chromatography, gel filtration, and preparative electrophoresis. The sample prepared from normal granulocytes contained a single protein with LAP activity having a molecular weight of 61,000 as determined by SDS gel electrophoresis. The sample from the CGL blast-phase cells, however, demonstrated two proteins with alkaline phosphatase activity, one with a molecular weight of 61,000 (LAPs) and one with a molecular weight of 45,000 (LAPf). Differential heat inactivation and distinct isoelectric points of the two isozymes suggest that they are different proteins. We interpret our data to suggest two closely related LAP alleles whose expression is controlled independently. This may represent either genetic heterogeneity or induction of "tumor marker" gene expression.

Alkaline Phosphatase↗
PubMed1985

Noncaseating pulmonary granulomas associated with small cell carcinoma of the lung.

Noncaseating pulmonary granulomas are rarely associated with primary carcinoma of the lung. The patient described herein presented with constitutional symptoms and nodular pulmonary infiltrates associated with noncaseating granulomas without evident neoplasm in both transbronchial and open lung biopsy specimens. Despite corticosteroid therapy for presumed sarcoidosis, chest roentgenographic findings worsened and repeated transbronchial biopsy 12 months after the onset of initial symptoms revealed small cell carcinoma of the lung. Twenty-two months after initiation of chemotherapy, the patient is well with no evidence for carcinoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

Myosin and paramyosin are organized about a newly identified core structure.

Myosin isoforms A and B are differentially localized to the central and polar regions, respectively, of thick filaments in body wall muscle cells of Caenorhabditis elegans (Miller, D. M. III, I. Ortiz, G. C. Berliner, and H. F. Epstein, 1983, Cell, 34:477-490). Biochemical and electron microscope studies of KCl-dissociated filaments show that the myosin isoforms occupy a surface domain, paramyosin constitutes an intermediate domain, and a newly identified core structure exists. The diameters of the thick filaments vary significantly from 33.4 nm centrally to 14.0 nm near the ends. The latter value is comparable to the 15.2 nm diameter of the core structures. The internal density of the filament core appears solid medially and hollow at the poles. The differentiation of thick filament structure into supramolecular domains possessing specific substructures of characteristic stabilities suggests a sequential mode for thick filament assembly. In this model, the two myosin isoforms have distinct roles in assembly. The behavior of the myosins, including nucleation of assembly and determination of filament length, depend upon paramyosin and the core structure as well as their intrinsic molecular properties.

Animals↗
PubMed1985

Studies of Root Function in Zea mays: III. Xylem Sap Composition at Maximum Root Pressure Provides Evidence of Active Transport into the Xylem and a Measurement of the Reflection Coefficient of the Root.

The cut ends of excised Zea mays roots were sealed to a pressure transducer and their root pressures recorded. These rose approximately hyperbolically to a maximum value of 4.21 +/- 0.34 bar after 30 to 40 minutes. Xylem exudate could not be collected at this pressure since the flow rate was zero. Samples of exudate were collected at lower applied pressures (DeltaP), however, and Deltapi, the osmotic pressure difference between them and the solution bathing the root, was measured by freezing point depression. A plot of DeltaP/Deltapi against J(v)/Deltapi, where J(v) is the volume flux, proved to be a straight line whose intercept, equal to sigma, the reflection coefficient, was 0.853 +/- 0.016. The maximum xylem concentrations of various chemical species were found by a similar extrapolative method and compared with those in the cell sap. This indicated that (a) Ca(2+), Mg(2+), NO(3) (2-), SO(4) (2-), and most amino acids move from the cells to the xylem down an electrochemical potential gradient; (b) relative to these ions H(+), NH(4) (+), glutamine and asparagine are actively transported into the xylem; and (c) H(2)PO(4) (-), and K(+) are actively retained in the symplasm.

Journal Article↗
PubMed1985

Studies of Root Function in Zea mays: IV. Effects of Applied Pressure on the Hydraulic Conductivity and Volume Flow through the Excised Root.

The volume flux, J(v), and the osmotic driving force, sigma big up tri, openpi, across excised root systems of Zea mays were measued as a function of big up tri, openP, the hydrostatic pressure difference applied across the root, using the pressure jump method previously described (Miller DM 1980 Can J Bot 58: 351-360). J(v) varied from 5.3% to 142% of its value in intact transpiring plants as a result of the application of pressure differences from -2.4 to 2.4 bar. The calculated hydraulic conductivity was 5.9 x 10(-4) cubic centimeters per second per bar per gram root and was independent of pressure. A model of root function similar to those appearing in the literature failed to provide quantitative accord with the data. A proposed model, which includes the effect of volume flux on the distribution of solutes in the symplasm, predicts accurately J(v) big up tri, openpi, and the xylem solute concentration as a function of big up tri, openP.

Journal Article↗
PubMed1985

Control of lysozyme gene expression in differentiating HL-60 cells.

We have investigated the control of lysozyme gene expression in HL-60 cells induced to differentiate into macrophage-like cells with phorbol myristate acetate (PMA). Differentiation, as evidenced by cellular adherence, and morphological changes corresponded temporally to an increase in nonspecific esterase activity. The lysozyme concentration in the medium of uninduced HL-60 cells was 10 micrograms/10(7) cells, increasing to a maximum of 46 micrograms/10(7) cells after 48 h incubation with PMA (16 nM). At 72 h the lysozyme concentration decreased to 16 micrograms/10(7) cells. Intracellular lysozyme activity remained constant throughout differentiation. If HL-60 cells were exposed to PMA for 24 h, washed, then maintained in normal medium, they differentiated normally, confirming their irreversible commitment to differentiate. The increase in lysozyme secretion by these cells, however, is markedly blunted suggesting that continued PMA treatment of differentiated cells is required for their secretion of lysozyme. There is no change in the rate of extracellular degradation of lysozyme during differentiation. The level of lysozyme mRNA does not correlate directly with the amount of lysozyme secreted into the medium. Hybridization of uninduced HL-60 cell RNA with a chicken lysozyme cDNA probe demonstrates moderate hybridization. There is a modest (five-fold) increase in lysozyme mRNA between 0 and 36 h of exposure to PMA, corresponding to the burst of lysozyme secretion by these cells. The lysozyme mRNA decreases to a level which is lower than the original baseline by 72 h, when the cells are still secreting substantial amounts of lysozyme. These data suggest that both transcriptional and post-transcriptional controls are operative in the control of lysozyme gene expression during the differentiation of HL-60 cells. They also imply that lysozyme secretion is not a necessary component in the macrophage-monocyte differentiation of these cells.

Animals↗
PubMed1985

In vivo differentiation of blast-phase chronic granulocytic leukemia. Expression of c-myc and c-abl protooncogenes.

A patient with chronic granulocytic leukemia in acute blastic transformation was treated with mithramycin, an RNA synthesis inhibitor, after in vitro exposure of her leukemic cells to mithramycin showed differentiation to normal appearing granulocytes. Mithramycin therapy in vivo resulted in a prompt and dramatic hematologic response. Before therapy, the patient's leukemic cells had high levels of transcription of the cellular myc and abl protooncogenes. After initiation of therapy, protooncogene mRNA decreased rapidly. These observations indicate that mithramycin can induce differentiation both in vitro and in vivo and suggest that such changes may be associated with altered oncogene expression.

Adolescent↗
PubMed1985

Purification of functional RNA from human granulocytes.

The presence, in granulocytes, of high levels of nuclease activity makes it difficult to isolate intact RNA from these cells. We have developed a method that allows purification of functional RNA from normal granulocytes as determined by capability for reverse transcription and in vitro translation. We have shown that a considerable amount of ribonuclease activity remains in granulocyte lysates, even after the addition of heparin or vanadyl ribonucleoside complexes. RNA isolated from such lysates demonstrates only minimal binding to oligothymidylic-cellulose and does not serve as a template for reverse transcription or in vitro translation. However, the extraction of frozen granulocytes into phenol in the presence of both heparin and vanadyl ribonucleoside allows the purification of relatively large quantities of RNA, which serves as an excellent template for reverse transcription and in vitro translation. Purification of granulocyte RNA by this method will facilitate study of granulocyte gene expression.

Chromatography↗
PubMed1984

Transforming growth factor-beta controls receptor levels for epidermal growth factor in NRK fibroblasts.

NRK fibroblasts exposed to transforming growth factor-beta (TGF-beta) show increased binding of radiolabeled epidermal growth factor (EGF) relative to untreated cells. The binding of another growth factor, rat insulin-like growth factor-II, is unaffected. The increase in EGF binding induced by TGF-beta is not due to inhibition of EGF processing nor to an alteration in the affinity of plasma membrane EGF receptors. However, treatment of the cells with TGF-beta does cause a rapid increase in the number of plasma membrane receptors for EGF. TGF-beta has little effect on the rate of overall protein synthesis, but the increase it induces in EGF binding can be completely inhibited by cycloheximide and tunicamycin. Thus a selective synthetic mechanism underlies TGF-beta action. Cells incubated with TGF-beta also show altered down regulation of their EGF receptors in response to the ligand; concentrations of EGF that can induce strong biological responses no longer decrease the plasma membrane receptor level below the basal state. These results agree well with the known specificity and synergism of the interaction between TGF-beta and EGF. Moreover, they describe a mechanism of growth control in which bioactive peptides act coordinately through a regulatory effect on the number of cell-surface receptors.

Animals↗
PubMed1984

Interactions of maitotoxin with voltage-sensitive calcium channels in cultured neuronal cells.

The dinoflagellate toxin maitotoxin (MTX) stimulated 45Ca2+ uptake in cultured NG108-15 neuroblastoma X glioma cells. Depolarizing stimuli (e.g., 50 mM K+) produced an immediate stimulation in Ca2+ uptake, whereas that produced by MTX occurred only after a lag period of about 2 min. MTX did not stimulate Ca2+ uptake into fibroblasts. Both 50 mM K+- and MTX-stimulated Ca2+ uptake was blocked by organic calcium channel antagonists (nitrendipine, D-600, diltiazem) at very low concentrations. Cd2+ was also a potent blocker. The novel dihydropyridine BAY K8644 enhanced Ca2+ uptake in the presence of 50 mM K+ but had no effect in 5 mM Ca2+. However, in the presence of MTX, BAY K8644 stimulated Ca2+ uptake in 5 mM K+. The effects of MTX were not blocked by tetrodotoxin but were decreased in Na+-free medium. MTX did not stimulate Na+ uptake into NG108-15 cells and did not alter [3H]nitrendipine binding to rat brain cortical synaptosomes. It is concluded that MTX may alter the voltage dependence of calcium-channel activation.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1984

Caprine aflatoxicosis: serum electrophoresis and pathologic changes.

Pathologic changes and serum electrophoretic patterns were determined in 30 male goats given aflatoxin B1 (AFB1) orally at 4 dosage levels (mg/kg of body weight/day): 0.1 for 34 days; 0.2 for 18 days; 0.4 for 10 days; or 0.0 for 29 days. Goats given AFB1 had increased mean concentrations of gamma-globulins and most had decreased mean concentrations of beta-globulins, although these changes in serum proteins were not significant (P greater than 0.05). At necropsy, ascites, pale livers, petechial hemorrhages, nasal discharge, and icterus were present. Microscopic changes included bile ductule proliferation, hepatocytic karyomegaly, hepatocellular degeneration, pneumonia, rhinitis, and proximal renal tubular nephrosis. Goats given the 2 smaller dosage levels of AFB1 lived longer and had more severe lesions. Goats may be a good model for the study of ruminant aflatoxicosis.

Aflatoxin B1↗
PubMed1984

Caprine aflatoxicosis: experimental disease and clinical pathologic changes.

Groups of 8 male crossbreed domestic goats were given 3 dosage levels of aflatoxin B1 [(AFB1) mg/kg of body weight/day] orally: 0.1 for 34 days; 0.2 for 18 days; or 0.4 for 10 days. Clinical condition, feed consumption, and selected blood values were determined. Clinical signs of toxicosis included decreased feed consumption, slight-to-moderate loss of body weight, mucopurulent nasal discharge, dyspnea, coughing, lethargy, icterus, diarrhea (4 goats), and subnormal body temperature 24 to 48 hours before death. Clinicopathologic changes included increases in total RBC count, PCV, hemoglobin concentration, serum bilirubin concentration, and serum activities of aspartate aminotransferase, isocitric dehydrogenase, and ornithine carbamyl transferase. Goats given the 2 smaller dosage levels of AFB1 had slight increases of serum total protein (TP) concentration compared with control goats, but goats given the larger dosage levels of AFB1 initially had a slight decrease in TP. Aflatoxin had little effect on total WBC count. Serum alanine aminotransferase (ALT) activities in goats given the 2 larger dosage levels of AFB1 were similar to those of control goats, but goats given the smallest dosage level of AFB1 had increased serum ALT activities. Aflatoxin did not produce consistent dose-related changes in serum alkaline phosphatase activities. Seemingly, goats are susceptible to aflatoxin. Onset of clinical signs was dose-related. Onset and magnitude of increases in PCV, hemoglobin concentration, serum bilirubin concentration, and activities of serum aspartate aminotransferase, ornithine carbamyl transferase, and isocitric dehydrogenase were dose-related. Changes in TP and activities of serum ALT and alkaline phosphatase were neither dose-related nor were they potentially useful indicators of toxicosis.

Acute Disease↗
PubMed1984

Altered isozyme patterns of leucocyte alkaline phosphatase in disease states.

Leucocyte alkaline phosphatase (LAP) is a granulocyte enzyme whose concentration varies in disease states. In order to determine whether the pattern of expression is altered in leukaemic granulocytes, we have analysed the LAP isozyme pattern of a series of normal subjects and patients with various haematological diseases. Electrophoretic patterns of partially purified LAP samples were determined by polyacrylamide gel electrophoresis in the presence of Triton X-100. These patterns were reproducible on repeated samples from the same patient. Presence of the LAPf and LAPs isozymes were determined after staining with the dye Fast Blue BB. Granulocytes were obtained from 15 normal subjects. Thirteen of these samples had only the LAPs isozyme. The other two had LAPs, plus a small amount (less than or equal to 10% of total) of LAPf activity. Eight patients with stable phase chronic myelogenous leukaemia (CML) had only small amounts of the normal LAPs isozyme and no evidence of LAPf . Of 11 patients with CGL who clinically had blast crisis. 10 had both LAPs and LAPf . The eleventh patient who was Ph1 negative had only LAPs. Three of five patients with polycythaemia vera had only the LAPs isozyme while two had both isozymes. Six patients with non-malignant leucocytosis had only LAPs. We interpret this data to indicate that the increased levels of LAP activity in some CGL blast crisis patients are primarily related to synthesis of the LAPf isozyme.

Alkaline Phosphatase↗
PubMed1984

Hematologic and immunologic responses of Holstein calves to a fire ant toxicant.

Holstein calves (3 to 5 months of age) were used to develop an animal model sensitive to environmental toxicants. In the present study, the fire ant toxicant AMDRO was fed (113.5 g/day/calf) to weanling castrated calves (9 test and 9 controls) for 7 weeks. As early as 14 days after the start of the AMDRO feeding, leukopenia was observed. Differential counts revealed significant non-transient decreases in lymphocytes and eosinophils. Eosinopenia was observed from days 21 to 49 of AMDRO treatment. Variability in hematocrit and hemoglobin values in treated and control calves precluded making a determination of trends due to toxicant exposure. The AMDRO treatment did not produce significant decreases in primary or secondary antibody responses to keyhole limpet hemocyanin or to Brucella abortus vaccination. It also did not produce suppression of cellular immunity, as determined by delayed-type hypersensitivity response to bacille Calmette-Guérin. Potential effects of AMDRO on thermoregulatory mechanisms were indicated by significant depressions of rectal temperature observed after 25, 32, and 39 days' treatment.

Animals↗
PubMed1983

Rates of ligand binding to periplasmic proteins involved in bacterial transport and chemotaxis.

The ligand reactions of three binding proteins involved in bacterial transport and chemotaxis have been examined by stopped flow, rapid mixing techniques. The processes measured were: L-arabinose, D-galactose, and D-fucose binding to the Escherichia coli L-arabinose-binding protein; L-histidine binding to the Salmonella typhimurium L-histidine-binding protein; and D-maltose, maltotriose, cyclic maltohexaose, and cyclic maltoheptaose binding to the E. coli D-maltose-binding protein. Changes in tryptophan fluorescence were monitored, and the resultant time courses were analyzed quantitatively in terms of a simple one-step binding process. The fitted association rate constants for sugar binding are all about 1-3 X 10(7) M-1 s-1; variation in the affinity constants is expressed primarily by changes in the dissociation rate constants, 1-100 s-1. The sugar-binding proteins react at equal rates with the alpha and beta anomeric forms of their substrates. The ligand dissociation rates measured in vitro are consistent with the corresponding Vmax values observed for in vivo active transport. The association rate constant for the L-histidine-binding protein is 5-10 times greater than the corresponding rate constants for the sugar-binding proteins. A similar, large bimolecular rate, approximately 1 X 10(8) M-1 s-1, has been observed for the E. coli L-glutamine-binding protein (Weiner, J. H., and Heppel, L. A. (1971) J. Biol. Chem. 246, 6933-6941) and appears to reflect favorable electrostatic interactions between the charged amino acid and the surface of the protein molecule.

ATP-Binding Cassette Transporters↗
PubMed1983

Transforming growth factor-beta in human platelets. Identification of a major storage site, purification, and characterization.

Acidic ethanol extracts of human platelets induced non-neoplastic normal rat kidney fibroblasts to undergo anchorage-independent growth. Less than 100 ng/ml of the crude extract elicits 50% of the maximal biological response when assayed in the presence of epidermal growth factor (2.5 ng/ml). In the absence of epidermal growth factor, the potency of the extract decreased 1,000-fold. These results show that platelets contain a type beta transforming growth factor. The specific activity of the platelet extract is 100-fold greater than that of other non-neoplastic tissues. The growth factor was purified to homogeneity by sequential gel filtration on Bio-Gel P-60 columns, first in the absence and then in the presence of urea. As determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, this transforming growth factor-beta is a protein of 25,000 daltons. It is composed of two 12,500-dalton subunits held together by disulfide bonds. These results, as well as its amino acid composition and its lack of strong mitogenic activity, show that this protein is distinct from platelet-derived growth factor. When completely purified, transforming growth factor-beta elicits 50% of its maximal biological response at concentrations less than 5 x 10(-12) M.

Amino Acids↗