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Biomedical subjects

B Wold

Publications and source records attributed to B Wold.

46 records · Page 3Linked to original sources
PubMed1988

Constitutive and metal-inducible protein:DNA interactions at the mouse metallothionein I promoter examined by in vivo and in vitro footprinting.

A method of high resolution in vivo footprinting has been developed and used to survey the mouse metallothionein I (MT-I) promoter for protein : DNA interactions associated with basal-level transcription and with high-level metal-induced transcription. This promoter and its associated regulatory region is structurally complex. It contains multiple potential binding sites for metal regulatory factors and for other transcription factors, including SP1 and MLTF. In several cases potential recognition sites overlap, and the experiments reported here provide a view of which sites are utilized in vivo. These data also show how the pattern of protein : DNA contacts changes when cells are shifted from basal-level expression to metal-induced expression. The noninduced footprint pattern consists of interactions at basal elements that are thought to be responsible for the moderate transcription of this gene in the absence of added metals. These interactions remain unchanged upon metal induction. When MT-I expression is increased by exposing cells to zinc or cadmium, a new footprint pattern is observed. It includes the basal interactions and a new set of metal-dependent footprints that are positioned over all five genetically defined metal responsive elements (MREs), MRE-A--MRE-E. In addition, these data identify a sixth probable MRE, MRE-F, which displays a dimethylsulfate (DMS) footprint similar to that at other MREs.

Alkylating Agents↗
PubMed1988

Dental health habits in Austria, England, Finland and Norway.

Individually, people can prevent dental caries by sugar restriction and periodontal disease by toothbrushing. The aim of this study was to determine the toothbrushing frequency and consumption of sweets and soft drinks in some European countries. The data were obtained during the winter of 1983-84 from schoolchildren aged 11.5, 13.5 and 15.5 in Austria, England, Finland and Norway. Except for England, the samples were nationally representative. The questionnaires were completed at school. Dental health habits apparently were best in Norway, as the toothbrushing frequency was highest and the consumption of sweets and soft drinks was lowest. The toothbrushing frequency of boys was lowest in Finland. The consumption of sweets and soft drinks was very high in Austria and England. Such international comparisons should be used when evaluating and directing national programmes of preventive dentistry.

Adolescent↗
PubMed1987

Poly-L-ornithine-mediated transformation of mammalian cells.

Poly-L-ornithine has been used to introduce DNA and RNA into mammalian cells in culture. Ornithine-mediated DNA transfer has several interesting and potentially useful properties. The procedure is technically straightforward and is easily applied to either small or large numbers of recipient cells. The efficiency of transformation is high. Under optimal conditions, 1 to 2% of recipient mouse L cells take up and continue to express selectable marker genes. DNA content of transformants can be varied reproducibly, yielding cells with just one or two copies of the new gene under one set of conditions, while under a different set of conditions 25 to 50 copies are acquired. Cotransformation and expression of physically unlinked genes occur at high efficiency under conditions favoring multiple-copy transfer. Polyornithine promotes gene transfer into cell lines other than L cells. These include Friend erythroleukemia cells and NIH 3T3 cells. Both are transformed about 1 order of magnitude more efficiently by this procedure than by standard calcium phosphate products. However, the method does not abolish the large transformation efficiency differences between these cell lines that have been observed previously by other techniques. (vi) mRNA synthesized in vitro was also introduced into cells by this method. The RNA was translated resulting in a transient accumulation of the protein product.

Adenine Phosphoribosyltransferase↗
PubMed1980

Altering genotype and phenotype by DNA-mediated gene transfer.

Transformation, or DNA-mediated gene transfer, permits the introduction of new genetic information into a cell and frequently results in a change in phenotype. The transforming DNA is ultimately integrated into a recipient cell chromosome. No unique chromosomal locations are apparent, different lines contain the transforming DNA on different chromosomes. Expression of transformed genes frequently results in the synthesis of new polypeptide products which restore appropriate mutant cells to the wild-type phenotype. Thus transformation provides an in vivo assay for the functional role of DNA sequence organization about specific genes. Transforming genes coding for selectable functions, such as adenine phosphoribosyltransferase or thymidine kinase, have now been isolated by utilizing transformation in concert with molecular cloning. Finally, transformation may provide a general approach to the analysis of complex heritable phenotypes by permitting the distinction between phenotypic changes without concomitant changes in DNA and functional genetic rearrangements.

Adenine Phosphoribosyltransferase↗
PubMed1979

Introduction and expression of a rabbit beta-globin gene in mouse fibroblasts.

The cloned chromosomal rabbit beta-globin gene has been introduced into mouse fibroblasts by DNA-mediated gene transfer (transformation). In this report, we examine the expression of the rabbit gene in six independent transformants that contain from 1 to 20 copies of the cloned globin gene. Rabbit globin transcripts were detected in two of these transformants at steady-state concentrations of 5 and 2 copies per cell. The globin transcripts from one cell line are polyadenylylated and migrate as 9S RNA on methylmercury gels. These transcripts reflect correct processing of the two intervening sequences but lack 48 +/- 5 nucleotides present at the 5' terminus of rabbit erythrocyte globin mRNA.

Animals↗
PubMedDate not supplied

Managers' perceptions of radiographers' skills: current and future needs.

As the healthcare delivery system changes, it is imperative to assess the skills of practitioners to ensure consistency between educational preparation and work place needs. The purpose of this study was to examine radiology managers' perception of selected workplace skills and new radiography graduates' ability to perform them. A random sample of 1,932 members of the American Healthcare Radiology Administrators (AHRA) received a questionnaire containing 35 skills categorized as basic, intermediate or advanced. Skills were ranked by the magnitude of the difference between managers' rating of importance of each skill and their rating of graduates' ability to perform that skill satisfactorily. In the basic skill area, the four top-ranked skills represented problem-solving ability or critical thinking. Of the five highest-ranked intermediate skills, the top three were patient care skills: venipuncture, taking vital signs and monitoring patient equipment. In the advanced skill area, six skills exhibited high values for the difference between importance and ability. Two of those related to patient care, three were non-technical and the sixth was the ability to perform CT in addition to basic radiography. Employers and educators should work together to seek educational methods that produce radiographers who are better prepared for the fast-changing workplace.

Adult↗
PubMedDate not supplied

A comparison of student radiographic reject rates.

Educators and administrators often are called upon to estimate the economic considerations of students in radiology departments for clinical education. Yet, little has been written about student radiographic reject rates. This study assessed the radiographic reject rate of 320 first- and second-year students from 21 hospital- and college-sponsored programs in 18 states.

Humans↗
PubMedDate not supplied

An analysis of radiographic repeat and reject rates.

A literature search of the past 20 years of publications on radiographic repeat/reject rates located 11 reports of 48 studies. A significant unpublished 12th report added a 49th. This article evaluates these studies to propose mean radiographer repeat/reject rates and reasons for economic uses in administrative evaluations. A comprehensive bibliography provides a resource for future repeat rate studies.

Quality Control↗