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Biomedical subjects

A K Williams

Publications and source records attributed to A K Williams.

35 records · Page 2Linked to original sources
PubMed1991

Comparison of cytopathic and noncytopathic isolates of bovine viral diarrhea virus by oligonucleotide fingerprinting.

The molecular technique of RNA fingerprinting was used to characterize the genomes of 5 isolates of bovine viral diarrhea virus (BVDV): 2 viral pairs from the same animal, BVD-ILN/BVD-ILC and BVD-TGAN/BVD-TGAC, and the cytopathic viral prototype, BVD-NADL. Oligonucleotide patterns from the viruses were compared, and unique and overlapping oligonucleotides were identified. A comparison of the fingerprints indicated that the genome of each virus was distinguishable by the T1 RNase oligonucleotide fingerprinting technique. The greatest similarity observed was between oligonucleotides from BVD-ILC and BVD-ILN. Eighteen large oligonucleotides were conserved in all 5 BVDV isolates studied. We found that within a pair of BVDV, the cytopathic fingerprint was different from the noncytopathic fingerprint, indicating that cytopathic and noncytopathic BVDV may be distinct viruses.

Animals↗
PubMed1991

AIDS: knowledge and attitudes of student nurses in Australia and Canada.

In summary it would appear that Australian and Canadian nursing students, at least in these limited samples, generally have similar knowledge and attitudes regarding AIDS. This study, with its acknowledged limitations, could be regarded as a pilot study for future collaborative comparative research, targeting a wider population of nursing students in two very similar countries.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Rehabilitation of chronic stroke patients: changes in functional performance.

Forty stroke patients who were at least one year post-onset completed a one-month intensive rehabilitation program. The month before the program served as a control period. During the program, patients received individual sessions in occupational and physical therapy four days a week, and they participated in group activities on the fifth day. Therapy emphasized instruction in motor planning, balance and weight shift, and the use of adaptive equipment; these motor abilities were then practiced within real life situations. The patients demonstrated significant improvement in the outcome measures of weight shift, balance, and ADL scores after the one-month rehabilitation program (weight shift: F = 16.1, p = .0001; balance: F = 6.26, p = .0007; ADL: F = 13.8, p = .0001). They retained these new skills during a three-month follow-up period.

Activities of Daily Living↗
PubMed1988

Association of pain and physical dependency with depression in physically ill middle-aged and elderly persons.

To investigate the relationship of pain and physical dependency to depression, the authors conducted a panel survey of 133 middle-aged and elderly persons with recent exacerbations of various physical illnesses. Of the original 133 subjects, 114 participated in two in-depth personal interviews conducted about three months apart. Variables that were measured included age, income, social support, physical dependency, pain, and depression. Physical dependency was moderately associated with depression (r = .27). A multiple regression analysis performed to control for the other variables, however, revealed that physical dependency had little effect on depression (R2 change = .03). Correlation (r = .41) and regression (R2 change = .13) analyses indicated that pain was an important factor in level of depression even after controlling for all of the other variables.

Activities of Daily Living↗
PubMed1984

Oligodendrocyte proliferation and CNS myelination in cultures containing dissociated embryonic neuroglia and dorsal root ganglion neurons.

In this report we have described several aspects of glial development in cultures containing dissociated DRG neurons and glial cells obtained from dissociated spinal cord at least a week prior to the onset of in vivo myelination. With time in culture the dissociated neurons and glia interact and become organized into 3-dimensional structures possessing many features characteristic of developing CNS in vivo. We have presented evidence that some of the glial cells proliferate and differentiate into galactocerebroside positive (GC+) cells and that some produce myelin sheaths. Thymidine was incorporated into precursors of GC+ cells, but not into cells which were already GC+. Nearly all the astrocytes in areas where neurons were present participated in the formation of large fascicles, and it was within such fascicles that most myelin was formed, suggesting a possible role for astrocytes in creating a favorable microenvironment for myelination. Both the formation of myelin sheaths and the morphological maturity of the oligodendrocytes within the fascicles indicated that oligodendrocyte differentiation proceeded practically to completion in these cultures. In conclusion we believe that the culture system herein described provides an excellent model for in vitro studies of CNS development, while retaining some of the advantages of dissociated cell cultures as well as the possibility of separating and re-uniting the various cell types of interest.

Animals↗
PubMed1980

Comparison of nerve cell and nerve cell plus Schwann cell cultures, with particular emphasis on basal lamina and collagen formation.

The availability of cultures of normal cells (NCs) and Schwann cells (SCs) with and without fibroblasts has allowed us to investigate the sources of endoneurial and perineurial constituents of peripheral nerve. NCs cultured alone, devoid of ensheathment but healthy in appearance, lack basal lamina and extracellular fibrils. In contrast, when SCs accompany NCs, basal lamina and extracellular fibrils are consistently visible around SCs in outgrowth areas formed de novo in culture. These fibrils average 18 nm in diameter, exhibit a repeating banding pattern, and are trypsin-resistant and collagenase-sensitive. Collagen synthesis is also indicated by the incorporation of [14C]proline into peptide-bound hydroxy-proline in NC + SC or SC cultures. That the [14C]hydroxyproline polypeptides formed in NC + SC cultures are collagenous was determined in part by pepsin digestion-ammonium sulfate precipitation-polyacrylamide gel electrophoresis techniques; the 14C-polypeptides migrate to the positions of alpha 1 (I), alpha 2, alpha 1 (III), and alpha B chains of type I, type III, and A-B collagens. Also formed are thin, ruthenium red-preserved strands interconnecting basal laminae. SC ensheathment of axons is similar to that found in the animal; one SC is related to a number of unmyelinated axons or a single myelinated axon. This proclivity to ensheathe and myelinate axons indicates that SC function is not lost during the preparative procedures or after lengthy isolation in culture and provides the most reliable means for SC identification. Perineurial ensheathment and macrophages are lacking in NC + SC culture preparations divested of fibroblasts. We conclude that SCs do not form perineurium or the larger diameter collagen fibrils typical of endoneurium but that in combination with neurons they generate biochemically detectable collagens and morphologically visible basal lamina and thin collagenous fibrils.

Animals↗
PubMed1980

Studies of Schwann cell proliferation. II. Characterization of the stimulation and specificity of the response to a neurite membrane fraction.

When prepared by methods utilized in our laboratory, pure populations of Schwann cells in culture do not divide, but, after recombination with peripheral sensory neurons or their processes, proliferate rapidly (Wood and Bunge, 1975, Nature (Lond.) 256:661--664). In this paper, we demonstrate that a membrane fraction prepared from sensory ganglion neurites is also mitogenic for Schwann cells and increases the labeling index (assessed by autoradiography after incubation of cells with tritiated thymidine) from less than 0.2 to 10% for primary cells, and from 0.4 to 18--19% for replated cells. The increased responsiveness of replated cells may reflect their greater access to the neurite membranes which is a consequence of the elimination of multiple cell layers after replating and the removal of the basal lamina. This stimulation was specific; addition of membrane preparations from other cell types (3T3, C1300, etc.) was not mitogenic. Ultrastructural analysis demonstrated apparent binding of neurite membranes to Schwann cells as well as significant phagocytosis of the membranes by the cells. The uptake of nonmitogenic membranes suggests that phagocytosis per se is not the stimulus of proliferation.

Axons↗
PubMedDate not supplied

HIV/AIDS: knowledge and attitudes of accident and emergency healthcare professionals.

The knowledge and attitudes of healthcare professionals in accident and emergency departments in Australia are poorly understood. The authors assessed knowledge of and attitudes toward HIV/AIDS and homophobia were assessed in a convenience sample of 111 healthcare professionals in three New South Wales teaching hospitals. Results indicated that respondents with low knowledge of HIV/AIDS used the media as their major source of education and had higher levels of fear of infection than their colleagues with higher knowledge. The study findings imply that quality health care for people with HIV/AIDS requires programs that provide correct information and address the fear of infection.

Emergency Service, Hospital↗