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Biomedical subjects

R Davis

Publications and source records attributed to R Davis.

At least 307 records · Page 17Linked to original sources
PubMed1991

Assessment of needs of adults with developmental disabilities in skilled nursing and intermediate care facilities in Illinois.

Findings are reported from a statewide assessment of the habilitation, medical, and behavioral training needs of adults with developmental disabilities in Illinois general nursing homes. Only 10% were determined to be appropriately placed in medical settings, and only 27% were enrolled in developmental training programs. A large proportion of those recommended for alternative residential settings had significantly more intense medical, adaptive behavior, self-care, and self-preservation needs than did residents who typically reside in residential facilities for persons with developmental disabilities. Historical barriers to addressing the residential and active treatment needs of the assessed residents were discussed as were recent program developments in Illinois and implications of this study for other states.

Activities of Daily Living↗
PubMed1991

Hemangiopericytoma of the sternum.

Hemangiopericytoma of the chest wall is a rare tumor. We describe a patient with malignant hemangiopericytoma of the sternum who was treated with primary surgical resection and discuss the clinical, radiographic, and histologic features of the case. Surgical resection is the primary mode of therapy. High-dose radiotherapy and chemotherapy with a doxorubicin hydrochloride-containing combination may be warranted in certain cases.

Aged↗
PubMed1990

Abnormal vitamin B6 status in childhood leukemia.

Vitamin B6 is involved in many biological processes of potential relevance to carcinogenesis and tumor growth, including DNA synthesis and maintenance of immunocompetence, yet very little information exists on B6 nutritional status in childhood leukemia. Using a radioenzymatic assay, the authors measured plasma pyridoxal 5'-phosphate (PLP), the biologically active form of B6, in 11 newly diagnosed untreated children with leukemia and 11 age-matched controls. The children with leukemia had significantly lower PLP levels than the controls. In 26 additional leukemia patients and 26 additional controls, a high-performance liquid chromatography assay also demonstrated lower plasma PLP levels in childhood leukemia compared with controls. These differences were significant for both acute lymphoblastic leukemia (ALL) and for acute nonlymphoblastic leukemia (ANLL). The PLP values did not correlate with indices of leukemia cell burden, but did correlate with reported B6 intake, suggesting that illness-related diet changes are at least partially responsible for the low PLP levels. Before any chemotherapy, overall nutritional status was suboptimal in 53% of ALL cases and 57% of ANLL cases. Newly diagnosed children with leukemia have suboptimal overall nutrition as well as suboptimal vitamin B6 status.

Adolescent↗
PubMed1990

Effects of low molecular weight B-cell growth factor on proliferation of leukemic cells from children with B-cell precursor-acute lymphoblastic leukemia.

Recently, low-molecular-weight B-cell growth factor (LMW-BCGF) has been reported to stimulate growth of leukemic cells from B-cell precursor-acute lymphoblastic leukemia (BCP-ALL). We further investigated the effects of LMW-BCGF on proliferation of leukemic clonogenic (progenitor) and nonclonogenic (progeny) cells from children with BCP-ALL (28 patients) and B-cell ALL (two patients). Patients were either at diagnosis (n = 18) or in relapse (n = 12). Response of leukemic progenitor cells was determined by culturing cells (10(5) cells/mL) in methylcellulose with 0.1 U/mL LMW-BCGF. Colonies (greater than 20 cells) were counted at day 7. The response of the leukemic progeny population was determined by DNA synthesis studies using tritiated-thymidine and by DNA quantitation with propidiumiodide for determination of cell-cycle status. LMW-BCGF supported growth of leukemic progenitor cells from 20 of 28 (71%) BCP-ALL and two of two B-cell ALL patients. Colony numbers ranged from 7 to 2,400 (mean 145, median 45). A dose-response effect in colony growth was noted, with an apparent plateau at approximately 2.0 U/mL LMW-BCGF. Colony cells were primarily of leukemic phenotype (CD19+/CD10+/-). LMW-BCGF also induced significant increases in leukemic progeny cell proliferation as measured by both thymidine incorporation (stimulation indexes of 1.6 to 34) and by cell-cycle assay (percentage S+ G2/M stimulation indexes of 1.6 to 6). LMW-BCGF was more effective in stimulating leukemic proliferation than three recombinant interleukins (rIL-2, rIL-3, rIL-4), although rIL-3 was able to support colony growth in 4 of 11 patients. These results indicate that LMW-BCGF and, to a lesser degree rIL-3, are able to stimulate proliferation of BCP-ALL progenitor and progeny cells, whereas rIL-2 and rIL-4 do not support progenitor cell proliferation and have only marginal effects on leukemic progeny cell proliferation.

Bone Marrow↗
PubMed1990

Assay of lymphokine-activated killer activity generated from bone marrow cells of children with acute lymphoblastic leukemia.

We recently reported that low molecular weight B-cell growth factor (LMW-BCGF) plus recombinant interleukin-2 (rIL-2) synergistically induced lymphokine-activated killer (LAK) activity from the bone marrow (BM) cells of children with acute lymphoblastic leukemia (ALL). The kinetics of cell growth, antigenic phenotype, and lytic activity of the generated effector cells were further analyzed in this study. BM cells from ALL patients with active disease and in complete remission (CR) were cultured with a combination of LMW-BCGF and rIL-2. Monoclonal antibodies (anti-CD3 and anti-Leu 19) and immunomagnetic beads were used to separate LAK cells into three subsets: CD3+/Leu 19-, CD3+/Leu 19+, and CD3-/Leu 19+. Cytotoxicity assays with different subsets were performed versus K562, Raji, and autologous leukemic cells, using a 3-hour 51Cr release test. There was a significant cell expansion of 54-fold (mean value) for CD3+ cells and 15-fold for Leu 19+ cells in culture with LMW-BCGF plus rIL-2 for 7 to 14 days, whereas no cell expansion was observed in culture with rIL-2 alone. Although NK activity (K562) was generated from leukemic BM cells in culture with rIL-2 alone, it is only about one third of that generated in culture with rIL-2 plus LMW-BCGF. Analysis of lytic activity of cells generated in the latter cultures demonstrated that CD3-/Leu 19+ cells expressed highest lytic activity against NK-sensitive K562 cells as well as against NK-resistant Raji cells. CD3+/Leu 19+ cells showed median cytotoxicity, and CD3+Leu 19- cells mediated only minimal cytotoxic activity. Also, lytic activity of CD3-/Leu 19+ cells against autologous leukemic blasts was noted in patients with active disease. Our results demonstrate that LAK activity generated from BM cells by LMW-BCGF and r-IL2 is mediated mainly by two types of Leu 19+ cells: CD3-/Leu 19+ NK cells and CD3-/Leu 19+ T cells. Although CD3+ T cells (both Leu 19+ and Leu 19-) mediated less antitumor cytotoxicity than CD3-/Leu 19+ cells, the former cells were the major expanding cell population in culture with LMW-BCGF and rIL-2. The new culture system may be effective in generation of cells with LAK activity for therapeutic use.

Adolescent↗
PubMed1990

Several types of adherent cells elaborate a dialyzable lymphopoietic cofactor (Abelson Growth Promoter).

We have cloned a stromal cell from mouse bone marrow selected on the basis of its ability to promote the growth of an Abelson virus-transformed pre-B cell line. These stromal cells have smooth muscle features, and the ultrafiltrate of stromal cell-conditioned medium has proliferative effects on all feeder layer-responsive mouse pre-B cell lines tested, as well as on normal pre-B cells. One of these low MW substances is a protease-resistant factor with an MW of approximately 450 Da which we designate Abelson Growth Promoter (AGP). AGP was initially characterized as an activity which promotes the growth of Abelson virus-transformed mouse pre-B cells, but it also promotes the growth of a ras-transformed pre-B cell line as a single agent and in synergistic fashion with recombinant interleukin (IL) 7. AGP as a single agent has no effect on normal pre-B cells, which have a brisk response to IL-7. In contrast, transformed pre-B cells display a blunted response to IL-7. We propose that AGP plays a role in normal lymphopoiesis by expanding clones of pre-B cells which have been activated by other stromal cell-derived signals, such as IL-7, and directly promotes the growth of nascently transformed pre-B cells.

Abelson murine leukemia virus↗
PubMed1990

Safe storage times for sterile dental packs.

Safe storage times were evaluated for three sterile packaging materials that are commonly used in dentistry. No significant differences were found among packaging materials. Only three packs of 300 produced positive cultures during the 1-year test period. There were no time-related trends. The contamination levels found were within the range that has been reported to occur as a result of inadvertent contamination during unpackaging and transfer of sterile instruments. The findings of this study support the proposal that contamination is event related, not time related; that is, sterile instrument packs remain sterile for at least 1 year unless a specific event causes contamination.

Dental Instruments↗
PubMed1990

Three-generation reproduction study with dioctyl sodium sulfosuccinate in rats.

Groups of 30 male and 30 female rats (F0) were fed diets containing 0, 0.1, 0.5, or 1.0% dioctyl sodium sulfosuccinate (DSS) for 10 and 2 weeks, respectively. The F0 animals were then mated to produce an F1 litter. Groups of 30 male and 30 female F1 animals were fed the same dose levels for at least 10 weeks postweaning, and the breeding program was repeated to produce F2 animals. F3 animals were produced from F2 animals by the same procedure. The study was terminated with the F3 weanlings. Test diets were fed continuously throughout the study. All F0, F1, and F2 adults and F3 weanlings (one/sex/litter) were necropsied and given a macroscopic examination. There were no effects on reproductive function for parental animals of either sex during any of the three generations in this study. At the highest dose level (1.0% DSS), body weights were lower than those of controls during the premating phase for males in all three generations and for F1 and F2 females. Body weights for F1 and F2 males and females in the 0.5% dose group were also low during the premating phase. Pup weights on Lactation Day 0 were significantly lower than those of controls only for the high-dose group during the third generation. However, lower pup weight gains in the mid- and high-dose groups resulted in significantly lower pup weights on Day 21 for all three generations. Perinatal pup survival across three generations ranged from 96 to 100% for the control and treated groups. Pup survival ranged from 95 to 100% for controls, from 98 to 100% for low- and mid-dose groups, and from 91 to 99% for the high-dose group. There were no treatment-related mortality and antemortem or macroscopic observations. In summary, DSS administered in the diet to three successive generations of rats at levels of 0.5 and 1.0% caused a reduction in body weights for parental males in all generations and for F1 and F2 females. Pup weights at the 0.5 and 1.0% dose levels were also lower than those of the control in all three generations. However, the reduced body weights did not interfere with development of normal reproductive performance. DSS at levels up to 1.0% had no effects on the reproductive function of either sex in any generation and produced no treatment-related antemortem or macroscopic observations.

Animals↗
PubMed1990

An investigation of vanishing bone disease.

Vanishing bone disease is a rare condition producing local deformity and instability. Fibrovascular tissue replaces bone completely but the mechanism of bone destruction and resorption is unknown and there is controversy regarding the presence or absence of osteoclasts in the disease. Radiography, clinical chemistry, light microscopy, transmission electron microscopy (TEM) and cytochemistry were used to investigate the condition of a young woman presenting early in the disease process. We detected atypical ultrastructure in osteoblasts and endothelial cells. The rare osteoclasts, numerous mononuclear phagocytes and vascular endothelium found in the condition reacted positively for the enzyme acid phosphatase. Aggressive local excision of diseased tissue and insertion of a free vascularized bone graft at an advanced stage of the disease, accompanied by subsequent radiotherapy for residual disease only were successful in rehabilitating the affected forearm and hand.

Adult↗