An analysis of the effects of ramp slope on people with mobility impairments.

A study was conducted to evaluate the usability of the range of ramp slopes allowed under the current ADA accessibility guidelines. One hundred seventy-one subjects of all ages and using different types of mobility aids traversed a 30-foot ramp varying in slope from 1:8 to 1:20. Data were recorded for pulse rate, energy expenditure, rate of travel, distance traveled, and the location of rest stops. Findings show that among all subjects only a few manual wheelchair users had difficulty traversing all 30 feet in ascent, even on slopes as steep as 1:8. Based on these results, changes to the technical requirements for ramp slope and length cannot be recommended at this time.

People with mobility impairments in the United States today and in 2010.

This article presents a study undertaken to develop a population profile of people with mobility impairments in the U.S.A. today and to estimate the profile of people with mobility impairments in the year 2010. The profile was developed under contract to the U.S. Architectural and Transportation Barriers Compliance Board (Access Board) as part of a project to examine technical requirements for ramp slope and length. The profile was used to establish a representative (both today and in the future) sampling frame for human subjects in the current project, as well as to guide the Access Board in developing accessibility guidelines in the future. The present article highlights findings concerning mobility impairments in the population today and trends likely to influence the future prevalence of such impairments. The findings have implications for accessibility requirements and disability policy in general.

An evaluation of grab bars to meet the needs of elderly people.

This paper reports the findings of a study that evaluated the ability of 66 ambulatory and 50 nonambulatory older people to toilet independently and safely. A repeated measures research design included eight test trials in which participants got on and off a toilet using four different grab bar configurations each at two different toilet seat heights. Each trial was video-taped in order to determine patterns of grab bar use for each toilet height/grab bar configuration. In addition, pretrial and posttrial interviews were conducted to determine participant preferences and perceived safety. Results of this study indicate that some grab bar configurations that were not code-compliant were preferred and were used more often than configurations that were designed to meet Americans with Disabilities Act Accessibility Guidelines. These findings raise questions as to whether legally mandated grab bar requirements are appropriate for older individuals.

Human ceruloplasmin. Tissue-specific expression of transcripts produced by alternative splicing.

Ceruloplasmin (CP) is a plasma glycoprotein that transports copper throughout the body. In previous studies (Yang, F., Naylor, S., Lum, J., Cutshaw, S., McCombs, J., Naberhaus, K., McGill, J., Adrian, G., Moore, C., Barnett, D., and Bowman, B. (1986) Proc. Natl. Acad. Sci. U. S. A. 83, 3277-3261), two CP cDNA clones, CP-1 and CP-2, from a human cDNA library, differed from each other by the presence or absence, respectively, of 12 nucleotide bases encoding a deduced sequence of Gly-Glu-Tyr-Pro near the carboxyl-terminal region of the ceruloplasmin molecule. Examination of genomic DNA demonstrates that the two CP mRNAs are produced from a single gene by alternative spliced patterns. The additional amino acids deduced in CP-1 are products of alternative splicing within an intron of the CP gene at a site 12 nucleotide bases 3' to the commonly used site of CP-2. The CP-1 mRNA transcript encoding four extra amino acids appeared as a minor species accompanying CP-2 mRNA in placenta and chondrocytes. CP-1 mRNA was the predominant CP transcript in a lymphoblastic leukemia cell line, CEM. The mRNA examined from other tissues contained only CP-2 mRNA transcripts. These findings predict that alternative RNA splicing may lead to the differential expression of CP genomic sequences and produce alternate isoforms from a single CP gene in specific tissues.

Human oncogenes in mouse/human microcell hybrids.

DNA-mediated gene transfer has been used successfully in many experiments to identify and isolate transforming sequences from human tumors and tumor cell lines. This work was done to compare the efficiency of that technique to microcell-mediated chromosome transfer in the transformation of NIH 3T3 mouse fibroblast cells. Our hope was that oncogenes introduced into a cell in chromosomal form would also be effective in the transformation of NIH 3T3 cells. The study revealed, however, that microcells from cell lines that contain transforming sequences identified by DNA-mediated gene transfer were unable to transform NIH 3T3 cells, although other human genes were expressed in the microcell hybrids. Several possible mechanisms are given and discussed. This research may provide important insight into the possible control of oncogenes in intact human tumor cells.

General protocol for microcell-mediated chromosome transfer.

We have developed a general technique for making micronucleated cells to use in microcell-mediated chromosome transfer. Growing cells are blocked in mitosis with colcemid, placed in a hypotonic solution for 10 min, and returned to culture medium for 24 h. This treatment promotes the formation of micronuclei within lymphoblast or fibroblast cells. The microcells are generated by cytochalasin B treatment on a Percoll density gradient centrifuged at 43,500g. The resulting mixture of microcells, whole cells, and karyoplasts is filtered through 3-micron pores to obtain a pure microcell preparation. The microcells are fused to recipient whole cells using phytohemagglutinin-P and polyethylene glycol. Advantages of this technique are: donor cells need not be attached to a substrate; and cell lines which form micronuclei in low frequency can still be used efficiently as microcell donors.

Multidrug-resistant phenotype cosegregates with an amplified gene in somatic cell hybrids of drug-resistant Chinese hamster ovary cells and drug-sensitive murine cells.

Gene amplification has been associated with multidrug resistance (MDR) in several drug-resistant Chinese hamster ovary (CHO) cell lines which exhibit cross-resistance to other unrelated, cytotoxic drugs. In situ hybridization studies (Teeter et al., J. Cell Biol., in press) suggested the presence of an amplified gene associated with the MDR phenotype on the long arm of either of the largest CHO chromosomes (1 or Z1) in vincristine-resistant cells. In this study, somatic cell hybrids were constructed between these vincristine-resistant CHO cells and drug-sensitive murine cells to determine the functional relationship between the chromosome bearing the amplified sequences and the MDR phenotype. Hybrids exhibited primary drug resistance and MDR in an incomplete dominant fashion. Hybrid clones and subclones segregated CHO chromosomes. Concordant segregation between vincristine resistance, the MDR phenotype, the presence of the MDR-associated amplified sequences, overexpression of the gene located in those sequences, and CHO chromosome Z1 was consistent with the hypothesis that there is an amplified gene on chromosome Z1 of the vincristine-resistant CHO cells which is responsible for the MDR in these cells. A low level of discordance between CHO chromosomes Z8 and 2 and the drug resistance phenotype suggests that these chromosomes may contain genes involved with the MDR phenotype.