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W M Miller

Publications and source records attributed to W M Miller.

14 recordsLinked to original sources
PubMed1992

Beneficial effects of reduced oxygen tension and perfusion in long-term hematopoietic cultures.

Growth of hematopoietic stem and progenitor cells found in the MNC fraction of human cord blood was evaluated under atmospheres containing reduced (5%) and normal (20%) oxygen tension. Reduced oxygen tension increased total cell numbers by as much as 5-fold in cord blood suspension cultures, but this effect was less pronounced in cultures containing an irradiated bone marrow stromal cell layer. However, reduced oxygen tension resulted in a substantial increase in both the number and frequency of colony-forming cells observed in both types of LTHC studied. Under low oxygen, CFU-C progenitor cell numbers were as much as 10-fold higher. Finally, reduced oxygen tension slowed the rate of irradiated stromal layer degeneration, as judged by cell counts and microscopic examination. These results indicate that low oxygen, which better approximates the in vivo environment, enhances the growth and maintenance of human stromal and progenitor cells in vitro. These low oxygen findings were then applied to a murine model LTHC perfusion system. In this system, irradiated 3T3 stromal layer integrity was improved under low oxygen and was substantially further improved with continuous medium perfusion. Cell counts and flow cytometry analysis indicated that the total cell production and the production of immature cells from murine bone marrow MNC on irradiated 3T3 cells were significantly enhanced under low oxygen with perfusion. After three weeks of culture, a 24-fold higher number of Thy1.2lo F4/80- MAC1- cells (indicative of murine stem and progenitor cells) was observed in the perfusion system as compared with static culture under ambient oxygen.

Animals↗
PubMed1992

Modulation of glutathione level in CHO cells. Effects of oxygen concentration and prior exposure to hypoxia.

A microtiter-plate assay has been developed for total intracellular glutathione that facilitates multiple-sample analysis and reduces the amount of time and chemicals required. Sonication time, pH, and storage conditions were identified as key parameters that affect the accuracy of the assay. Using this assay, it was found that CHO cells increase their glutathione level under higher oxygen tension. This adaptive response suggests that a rise in glutathione may be used as an indicator of oxidative stress. Based on this criterion, it was found that hypoxic and anoxic cells are sensitized to reoxygenation. This sensitization could not be attributed to a drop in glutathione during low oxygen exposure because the glutathione content reached a basal level at a PO2 of about 40 torr.

Animals↗
PubMed1992

Effects of synergistic cytokine combinations, low oxygen, and irradiated stroma on the expansion of human cord blood progenitors.

Expansion of hematopoietic progenitor cells in the mononuclear cell (MNC) fraction of human cord blood was evaluated under atmospheres containing reduced (5%) and normal (20%) oxygen tensions. Cells were cultured with synergistic cytokine combinations in suspension (without stroma) and on irradiated bone marrow stroma. Addition of interleukin (IL)-3 and IL-6 (IL-3/IL-6) provided a greater expansion of both total and progenitor cells than IL-1 and IL-3 (IL-1/IL-3). IL-3/IL-6 maintained a higher level of progenitors throughout the 8-week culture period, whereas progenitors disappeared earlier from cultures with IL-1/IL-3. This indicates that an earlier cell type was affected by IL-3/IL-6, and/or that IL-3/IL-6 favored self-renewal while IL-1/IL-3 induced differentiation. Reduced oxygen tension enhanced the productivity of these long-term hematopoietic cultures (LTHC) under all conditions tested. In suspension cultures, reduced oxygen increased cumulative total cell production by 125% and 167%, and cumulative progenitor production by 68% and 21%, with IL-1/IL-3 and IL-3/IL-6, respectively. The presence of irradiated stroma increased cumulative progenitor cell production almost threefold in cultures without cytokines. In cultures with cytokines, the beneficial effect of stroma was less significant, but was greater under 20% O2 than 5% O2. Cultures under 5% O2 provided more progenitors and often maintained progenitors for 1 to 2 weeks longer than those under 20% O2. To quantitate more precisely the shift in cell populations induced by IL-3/IL-6 and stroma in cultures under 5% O2, flow cytometry analysis was used. By week 3, the addition of IL-3/IL-6 stimulated a 15-fold and 25-fold expansion of promyelocytes (CD15+CD11b-) in suspension and stromal cultures, respectively. Addition of IL-3/IL-6 also increased mature granulocyte (CD15hiCD11b+) and monocyte (CD15loCD11b+) numbers, while no effect was seen on T-(CD3+) or B- (CD19+) lymphocytes. Endogenous production of IL-6 was significantly higher under 5% O2 in both suspension and stromal cultures, and IL-6 production was increased threefold by the addition of IL-1/IL-3. Very little IL-1 beta was produced in these cultures, and endogenous IL-3 and tumor necrosis factor (TNF)-alpha were undetectable by enzyme-linked immunosorbent assay (ELISA) analysis.

Cell Division↗
PubMed1992

UDP-N-acetylhexosamine modulation by glucosamine and uridine in NCI N-417 variant small cell lung cancer cells: 31P nuclear magnetic resonance results.

Small cell lung cancer (SCLC) occurs as two neuroendocrine subtypes, SCLC-C (classic) and SCLC-V (variant). One reported difference is elevated levels of diphosphodiesters (DPDE) in the more differentiated SCLC-C subtype. DPDE have been identified as primarily UDP-N-acetylhexosamines (UDP-NAH) in a variety of tumors, and changes in DPDE levels have been observed during experiments designed to induce cell differentiation. UDP-NAH synthesis is controlled by negative feedback regulation of glutamine:fructose-6-P amidotransferase (EC 2.6.1.16), which can be circumvented by glucosamine. Using 31P nuclear magnetic resonance analysis of extracts and perfused cells, we have identified UDP-N-acetylglucosamine and UDP-N-acetylgalactosamine as the primary metabolites in the DPDE spectral region of SCLC-V N-417 cells. Glucosamine addition causes a rapid increase in UDP-NAH levels. At glucosamine: glucose ratios of 1:1 and 10:1 formation of the UDP-NAH intermediates N-acetylglucosamine 6-phosphate and UDP-N-acetylglucosamine 1-phosphate is also observed, indicating UTP limitation. Subsequent uridine addition results in depletion of the intermediates and increased UDP-NAH formation. Moreover, N-417 cells retain the capacity to rapidly convert uridine to UTP despite low ATP and phosphocreatine levels. This expansion of the uridine pool may represent an additional metabolic reserve not yet addressed in the design of therapy options.

Carcinoma, Small Cell↗
PubMed1992

Reduced oxygen tension increases hematopoiesis in long-term culture of human stem and progenitor cells from cord blood and bone marrow.

Growth of hematopoietic stem and progenitor cells found in the mononuclear cell (MNC) fraction of human cord blood and bone marrow was evaluated under atmospheres containing reduced (5%) and normal (20%) oxygen tension. Cord blood MNC were grown in suspension and on preestablished irradiated bone marrow stromal layers, whereas bone marrow MNC were used to initiate one-step long-term bone marrow cultures (LTBMC). Reduced oxygen tension resulted in a substantial increase in both the number and frequency of colony-forming cells observed in all three types of long-term hematopoietic cultures (LTHC) studied. At various time points under low oxygen, progenitor cell numbers were as much as 12-fold, 3-fold, and 4-fold higher for granulocyte-macrophage colony-forming units (CFU-GM), erythroid burst-forming units (BFU-E), and granulocyte erythrocyte macrophage megakaryocyte colony-forming units (CFU-GEMM), respectively. In addition to these numerical increases, progenitor cells were maintained for 1-2 weeks longer under low oxygen conditions. Reduced oxygen tension also increased total cell numbers by as much as fivefold in cord blood suspension cultures, but this effect on total cell numbers was less pronounced in cultures containing a stromal layer. The rate of irradiated stromal layer degeneration, as judged by cell counts and microscopic examination, was reduced under low oxygen. Finally, the beneficial effect of reduced oxygen was comparable to the effect of an irradiated stromal layer for maintaining cord blood progenitor cells in LTHC. These results indicate that low oxygen, which better approximates the in vivo environment, enhances the growth and maintenance of both stromal and progenitor cells for a longer period of time in vitro.

Bone Marrow↗
PubMed1991

Effect of wet or dry corn gluten feed on nutrient digestibility and milk yield and composition.

A 22-wk trial was conducted to determine variations in nutrient concentrations of wet and dry corn gluten feed and their effect on nutrient digestibility and milk yield and composition. Holstein cows (n = 48) were blocked at parturition by parity and assigned randomly within block to one of three diets. All cows were fed a control TMR containing corn silage, ground corn, and commercial concentrate plus 2.3 kg/d of alfalfa hay during the 2-wk adjustment period. Thereafter, control diet was fed as wet or dry corn gluten feed substituted for 27% of dietary DM supplied by the control diet. Each cow received TMR for ad libitum consumption. Variations in nutrient concentrations of corn gluten feed were observed throughout the trial. The coefficient of variation was highest for ADIN, and standard deviation was highest for NDF. Intake of CP and NDF and apparent digestibility of DM were greatest when wet or dry corn gluten feed was fed. No differences in DMI, milk yield, and percentages of milk protein, lactose, or SNF were observed, but milk fat percentage was lowest when dry corn gluten feed was fed. Results indicate that corn gluten feed can replace 27% of dietary DM without altering milk yield, but new deliveries should be sampled regularly and amounts fed adjusted to compensate for varying nutrient concentrations.

Animal Feed↗
PubMed1977

Metabolic fate of [14C]cefamandole, a parenteral cephalosporin antibiotic, in rats and dogs.

The biotransformation of the parenterally effective cephalosporin antibiotic cefamandole nafate (I) has been studied in rats and dogs. After rapid in vivo hydrolysis of the nafate pharmaceutical form to cefamandole (II), the antibiotic was found to be very resistant to metabolic degradation in both species. In dogs, cefamandole escaped metabolism and was eliminated as unaltered antibiotic almost exclusively by renal excretion. In rats, cefamandole was somewhat labile to metabolism; however, a major portion of the administered antibiotic was eliminated unchanged principally by renal excretion.

Animals↗
PubMed1977

Progressive hypereosinophilia with lung nodules due to thyroid carcinoma.

An elderly woman had dyspnea, a thyroid mass and multiple lung nodules on chest radiographs. She developed hypereosinophilia over a three-month period in which multiple diagnostic procedures were performed, without definition of the disease process. At post-mortem examination, the primary lesion was found to be a poorly differentiated carcinoma of the thyroid, metastatic to lung. This is the second case of hypereosinophilia related to metastatic thyroid carcinoma. The intensity of the hypereosinophilia in this case was increased by the administration of thyroid-stimulating hormone and by the development of necrosis of the lung nodules.

Aged↗
PubMed1976

Reaction pathways of in vivo stereoselective conversion of ethylbenzene to (-)-mandelic acid.

1. Mandelic acid formed in vivo from ethylbenzene as well as from various oxidation intermediates was laevo mandelic acid and was of surprisingly high optical purity. 2. Reaction sequences are proposed for the stepwise oxidation of ethylbenzene to mandelic acid. 3. Although the initial hydroxylation of ethylbenzene to methylphenyl-carbinol is stereoselective, the optical activity of mandelic acid is not established at this point since the optical centre is destroyed in the second step, dehydrogenation to acetopheneone. 4. Acetophenone appears to be a precursor of not only mandelic acid and benzoylformic acid but benzoic acid as well. 5. The route from acetophenone involves conversion to omega-hydroxyacetophenone and subsequent reduction to glycol and/or oxidation to phenylglyoxal. 6. The configuration of mandelic acid is determined either during reduction of hydroxyacetophenone or reduction of phenylglyoxal.

Animals↗