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Biomedical subjects

M Yoder

Publications and source records attributed to M Yoder.

At least 19 recordsLinked to original sources
PubMed2001

Marrow-derived cells populate scaffolds composed of xenogeneic extracellular matrix.

INTRODUCTION: The source of cells that participate in wound repair directly affects outcome. The extracellular matrix (ECM) and other acellular biomaterials have been used as therapeutic scaffolds for cell attachment and proliferation and as templates for tissue repair. The ECM consists of structural and functional proteins that influence cell attachment, gene expression patterns, and the differentiation of cells. OBJECTIVE: The objective of this study was to determine if the composition of acellular matrix scaffolds affects the recruitment of bone marrow-derived cellular elements that populate the scaffolds in vivo. METHODS: Scaffolds composed of porcine tissue ECM, purified Type I collagen, poly(L)lactic coglycolic acid (PLGA), or a mixture of porcine ECM and PLGA were implanted into subcutaneous pouches on the dorsum of mice. The origin of cells that populated the matrices was determined by first performing bone marrow transplantation to convert the marrow of glucose phosphate isomerase 1b (Gpi-1(b)) mice to cells expressing glucose phosphate isomerase 1a (Gpi-1(a)). RESULTS: A significant increase in Gpi-1(a) expressing cells was present in sites implanted with the porcine ECM compared to sites implanted with either Type I collagen or PLGA. Use of recipient mice transplanted with marrow cells that expressed beta-galactosidase confirmed that the majority of cells that populated and remodeled the naturally occurring porcine ECM were marrow derived. Addition of porcine ECM to the PLGA scaffold caused a significant increase in the number of marrow-derived cells that became part of the remodeled implant site. CONCLUSION: The composition of bioscaffolds affects the cellular recruitment pattern during tissue repair. ECM scaffolds facilitate the recruitment of marrow-derived cells into sites of remodeling.

Animals↗
PubMed1999

Regulation of the BBB during viral encephalitis: roles of IL-12 and NOS.

Intranasal infection of mice by Vesicular Stomatitis Virus (VSV) often leads to breakdown of the blood-brain barrier (BBB). The role of Interleukin 12 (IL-12) and nitric oxide synthase (NOS) was examined here. Wild-type (WT), NOS-1 knockout (KO), and NOS-3 KO mice were infected with VSV and treated with either IL-12 or medium. IL-12 treatment of uninfected hosts did not result in pathology. In contrast with WT and NOS-1 KO mice, where extensive gross and ultrastructural correlation of BBB breakdown were evident following infection, in NOS-3 KO mice, integrity of the BBB was observed. Thus NOS-3 activity in astrocytes, endothelial cells, or ependymal cells may play an essential role in regulating the BBB.

Animals↗
PubMed1999

Interaction between bacteriophage PBS1 and clay minerals and transduction of Bacillus subtilis by clay-phage complexes.

Bacteriophage PBS1 of Bacillus subtilis was rapidly adsorbed on montmorillonite (M) and kaolinite (K), and adsorption was maximal after 30min on both clays. There was no correlation between adsorption and the cation exchange capacity of the clays. Studies with sodium metaphosphate (a polyanion that interacts with positively charged sites on clay) indicated that positively charged sites on K were primarily responsible for the adsorption of the phage, whereas other mechanisms appeared to be involved in adsorption of the phage on M. X-ray diffraction and electron microscopic analyses showed that the phage partially intercalated M. Survival of the phage was increased by adsorption on the clays, and adsorbed phage maintained its ability to transduce bacterial cells for at least 30 days (the longest time studied) after the preparation of the clay-phage complexes. Electron microscopic observations indicated that transduction by the clay-phage complexes was primarily the result of the phage detaching from the clays in the presence of host cells.

Adsorption↗
PubMed1999

The Cummins model: a framework for teaching nursing students for whom English is a second language.

The health care system requires nurses with the language ability and the cultural knowledge to meet the health care needs of ethnic minority immigrants. The recruitment, admission, retention, and graduation of English as a Second Language (ESL) students are essential to provide the workforce to meet the demands of the multicultural community. Yet, ESL students possess language difficulties that affect their academic achievement in nursing programs. The application of the Cummins Model of language proficiency is discussed. The Cummins Model provides a framework for nursing faculty to develop educational support that meets the learning needs of ESL students.

Cultural Diversity↗
PubMed1998

Forced expression of Genesis, a winged helix transcriptional repressor isolated from embryonic stem cells, blocks granulocytic differentiation of 32D myeloid cells.

We recently isolated and characterized a novel member of the winged helix (formerly HNF-3/Forkhead) transcriptional regulatory family, termed Genesis. Genesis was found to be a transcriptional repressor expressed almost exclusively in embryonic stem cells or embryonal carcinoma cells. This expression rapidly declined when these cells were stimulated to differentiate. This expression pattern suggested that Genesis may play a role in cellular differentiation. To explore that possibility in a heterologous system of differentiation, Genesis was stably transduced into the IL-3-dependent myeloid cell line 32D using a retroviral expression vector. 32D cells overexpressing Genesis failed to mature normally when stimulated with G-CSF but continued to proliferate and maintained a primitive phenotype. This finding implicates Genesis in the regulation of development, and also implies that there may be common transcription pathways for many developing tissues.

Blotting, Northern↗
PubMed1996

Transport of CaM kinase along processes elicited by neuronal contact evokes an inhibition of arborization and outgrowth in D. melanogaster cultured neurons.

Transgenic Drosophila strains expressing an inhibitory peptide of Ca2+/calmodulin dependent protein kinase II (CaM kinase), or a constitutively activated CaM kinase, show altered neuronal process morphology compared to wild type in scanning electron microscopy (SEM) of cultured mature neurons from embryonic neuroblasts. We observed significantly enhanced process growth in cells with inhibited enzyme, and reduced process growth in cells with activated enzyme, suggesting that active CaM kinase is involved in the inhibition of neurite growth during development. The subcellular distribution of CaM kinase in wild type neuronal cultures was determined using a gold particle labeling procedure which allowed the mapping of the enzyme directly in the scanning electron microscope (SEM). Before neuronal contact there was little labeling of processes, but after connections had been made the processes were heavily labeled. Our results suggest that the major transport of CaM kinase to the terminals does not occur until after or during the formation of neuronal connections when a functional synapse might be formed. Taken together, these results suggest a target-dependent transport of the enzyme along processes and an inhibitory role for CaM kinase on neurite branching.

Animals↗
PubMed1996

Endogenously inhibited protein kinase C in transgenic Drosophila embryonic neuroblasts down regulates the outgrowth of type I and II processes of cultured mature neurons.

Embryonic neurons were cultured from transgenic Drosophila melanogaster expressing a highly specific pseudosubstrate inhibitor of protein kinase C (PKC). Flies homozygous for this transgene, which is under the control of the yeast UAS promoter, were crossed to flies homozygous for the yeast heat shock inducible transcription factor GAL 4. Following heat shock, the progeny express the pseudosubstrate inhibitor at high levels. This strategy, which has the advantage of avoiding the non-specific effects of drugs, was used to study the role of PKC in process growth of cultured, differentiating neuroblasts. An external gold particle labeling procedure using a cell surface antigen expressed by mature neurons and processes was used to visualize neuronal processes directly in the scanning electron microscope. We observed that cell cultures expressing a low concentration of the pseudosubstrate inhibitor showed a significant decrease in the number of type I and II processes as compared to control cultures, while the proportions of neuroblasts, ganglion mother cells (GMCs), and mature neurons in the clusters were little affected.

Amino Acid Sequence↗
PubMed1996

Ten steps to create an innovative community-based pediatric experience as part of a clinical practicum: a model.

Innovative and alternative learning experiences are needed for students to obtain essential parts of the pediatric nursing clinical experience. This article presents a Ten Step approach guide for nurse educators to develop and implement a community-based pediatric primary health care model in a clinical practicum. The community pediatric primary health care experience is part of the San Jose State University School of Nursing's Nurse Managed Centers. Our approach focuses on providing community-based primary health care by faculty and nursing students to culturally diverse, underserved children and families in community settings in and around the university.

Child↗
PubMed1993

Evaluating treatment efficacy by triangulation.

The project 'Efficacy of Support Groups for Mexican American Widows' was evaluated by triangulating results collected from different points of view. These included changes after one year in (1) measurement scores of standardized instruments, (2) assessment of adjustment to role of widow by the outsider and (3) evaluation by the widow herself. When subjects were categorized by their assignment to experimental or control groups, the scores on standardized instruments including the Beck Depression Inventory (BDI), the Center for Epidemiologic Study of Depression (CES-D), Anxiety State, Life Satisfaction and new scales measuring Somatic symptoms and Emotional symptoms had decreased from time 1 to time 5 for all widows. However, the widows participating in support groups showed significantly improved changes in these scores. The outsiders found the women who participated in the support groups to have a far better change to the role of widow than the control widows. The support group widows themselves described more positive changes in themselves than did control widows.

Adolescent↗
PubMed1992

Growth characteristics and expansion of human umbilical cord blood and estimation of its potential for transplantation in adults.

We estimated whether single collections of cord blood contained sufficient cells for hematopoietic engraftment of adults by evaluating numbers of cord blood and adult bone marrow myeloid progenitor cells (MPCs) as detected in vitro with steel factor (SLF) and hematopoietic colony-stimulating factors (CSFs). SLF plus granulocyte-macrophage (GM)-CSF detected 8- to 11-fold more cord blood GM progenitors [colony-forming units (CFU)-GM] than cells stimulated with GM-CSF or 5637 conditioned medium (CM), growth factors previously used to estimate cord blood CFU-GM numbers. SLF plus erythropoietin (Epo) plus interleukin 3 (IL-3) enhanced detection of cord blood multipotential (CFU-GEMM) progenitors 15-fold compared to stimulation with Epo plus IL-3. Under the same conditions, bone marrow CFU-GM and CFU-GEMM were only enhanced in detection 2- to 4- and 6- to 8-fold. Increased detection of cord blood CFU-GEMM correlated directly with decreased detection of cord blood erythroid burst-forming units (BFU-E). In contrast, adult bone marrow CFU-GEMM and BFU-E numbers were both enhanced by SLF plus Epo plus IL-3. This suggests that most cord blood BFU-E may actually be CFU-GEMM. Cord blood collections (n = 17) contained numbers of MPCs (especially CFU-GM) similar to the number found in nine autologous bone marrow collections. To assess additional sources of MPCs, the peripheral blood of 1-day-old infants was assessed. However, average concentrations of MPCs circulating in these infants were only 30-46% that in their cord blood. Expansion of cord blood MPCs was also evaluated. Incubation of cord blood cells for 7 days with SLF resulted in 7.9-, 2.2-, and 2.7-fold increases in numbers of CFU-GM, BFU-E, and CFU-GEMM compared to starting numbers; addition of a CSF with SLF resulted in even greater expansion of MPCs. The results suggest that cord blood contains a larger number of early profile MPCs than previously recognized and that there are probably sufficient numbers of cells in a single cord blood collection to engraft an adult. Although the expansion data must be considered with caution, as human marrow repopulating cells cannot be assessed directly, in vitro expansion of cord blood stem and progenitor cells may be feasible for clinical transplantation.

Age Factors↗
PubMed1987

Hot and cold in women's ethnotherapeutics: the American-Mexican West.

The purpose of this paper is to report the current status of hot/cold principles in the ethnotherapeutics of women of southwestern U.S.A., northwestern Mexico. The paper presents a secondary data analysis from three studies, including a data bank of Women's Ethnotherapeutic Agents derived from literature searches, interviews of women in research of Mexican American Grandmothers as Health Care Advisors, and research in the historical roots of the ethnotherapeutic agents used in contemporary domestic medicine. This report presents women's home remedies, what these remedies are believed to do, and the sources of this domestic therapy knowledge. It concentrates on persistence and change in one aspect of the theoretical base of these remedies, their humoral complexional classification. In the analysis of data from these studies, continuation of aspects of the hot/cold theory is demonstrated. It is suggested that the persistence is tacit, with the lack of articulated knowledge of humoral theory today stemming from the content of contemporary remedy books. Instead of arguing either diffusion or independent invention, commonly held ethnophysiological concepts are offered as a possible explanation for the persistence of hot and cold therapy practices.

Cold Temperature↗
PubMed1985

Bulk preparation and crystallization of the Escherichia coli elongation factor Tu-Ts complex.

A simple procedure for the preparation of 10-500 mg of the Escherichia coli elongation Tu-Ts complex is described. The protocol is based on the separate purification and quantitation of EF-Tu-GDP and EF-Ts, followed by mixing of equimolar amounts of each protein and removal of the displaced GDP by dialysis. Single crystals grown from the final product have been analyzed by X-ray diffraction techniques. The procedure is also applicable to the bulk preparation and crystallization of the trypsin-modified Tu-Ts complex. Quantitation of the elongation factors by three methods is presented.

Chromatography, Gel↗
PubMed1984

An improved bulk purification method for Escherichia coli elongation factor, Ts.

A bulk purification procedure has been designed to maximize the yield of Escherichia coli elongation factor, Ts, with a minimum of effort and time. The enzyme purification is achieved by DEAE-Sepharose and elongation factor Tu-affinity chromatographies. The typical yield is 150 mg/kg of E. coli (B) cells.

Chromatography, Affinity↗
PubMed1984

Affinity purification of aminoacyl-tRNA.

A procedure for separating Escherichia coli aminoacyl-tRNA from unacylated tRNA or components of the aminoacylation reaction, thereby achieving an aminoacyl-tRNA product with a very high specific activity, is described. The method utilizes the specific recognition of aminoacyl-tRNA for E. coli protein synthesis elongation factor Tu which has been immobilized on an affinity matrix. The application of the affinity procedure as a means of purifying a single aminoacyl-tRNA from an unfractionated mixture of tRNAs is also discussed.

Chemical Phenomena↗
PubMed1980

Inhibition of polymorphonuclear leukocyte adherence by prostacyclin.

The adherence of human PMNs to nylon fibers or endothelial cells is inhibited by exposure in vitro of the phagocytic cells to PGl2. The impaired adherence is transient and correlates with a rise in intracellular levels of cyclic AMP. Similarly, stimulation of human endothelial cells with sodium arachidonate, a precursor of PGl2, leads to impaired PMN adherence. On the other hand, PGl2 failed to alter O2- release and the bactericidal capacity of the PMNs. These findings suggest that PGl2 may play a role in regulating PMN adhesiveness to endothelial cells without compromising host defense.

Cell Adhesion↗