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Biomedical subjects

J Ryder

Publications and source records attributed to J Ryder.

30 records · Page 2Linked to original sources
PubMed1982

Perceived symmetry and visual matching.

The effects of perceived symmetry on physical-matching latency was evaluated. The stimuli were letter pairs made from the letters F, G, J, L. and R in either normal, reversed, or inverted orientations. When the same letter was used twice to form a pair, the different orientation-combinations produced four types of symmetry: rotational, vertical-axis bilateral, and translational symmetry, as well as a distorted version of horizontal-axis bilateral symmetry. Perceptual organization in the form of symmetry inhibited physical matching.

Discrimination Learning↗
PubMedDate not supplied

Effects of selective spinal cord lesions on the spinal motor evoked potential (MEP) in the rat.

The effects of selective spinal cord lesions on the motor evoked potential (MEP) in 21 rats were investigated. No significant change in peak amplitude was observed following lesions of the pyramidal tract. There was a significant decrease in peaks 1 and 2 with ventral funiculi lesions. All 4 peaks of the MEP were significantly reduced following lesions of the lateral funiculus. The most marked decrease in peak amplitude followed lateral funiculi lesions that involved the lateral grey of the spinal cord. In one animal where the lesion was confined to the grey matter in the cord there was a marked decrease in all peaks of the MEP. In 3 additional animals interruption of the descending tracts of the spinal cord via bilateral hemisections of the spinal cord failed to completely abolish the MEP. Increases in peak latency were also noted following spinal lesions. In some animals the increase in latency occurred in the absence of significant peak amplitude changes. The findings in this study refute the previously held position that the MEP in the rat arises from pyramidal tract activation. The role of the reticulospinal and propriospinal tracts in the generation and propagation of the MEP are discussed.

Animals↗
PubMedDate not supplied

Dynamic Recovery: comparative study of therapeutic communities in homeless shelters for men.

The Dynamic Recovery Project examined relationships between homelessness, substance abuse, and recovery, and investigated the effectiveness of the therapeutic community (TC) treatment model in helping homeless drug users move toward stable, drug-free living. This project compared two short-term TCs that were situated within pre-existing homeless shelters with a clean and sober dormitory. In a separate condition, peer counselors and staff were provided additional training in TC philosophy and practice to reduce program dropout. Dramatic decreases in drug and alcohol use at follow-up were verified by urinalysis. Length of time in treatment rather than specific program accounted for decreased alcohol and drug use. Important decreases in posttreatment criminality for both treatment programs were documented. The comparison group, starting with low criminality, experienced smaller, nonsignificant decreases unrelated to type of program or time in treatment. Major declines in Beck Depression Scores were evident, but were unrelated to groups or time in treatment. Training had no measurable impact on client retention or outcomes and there were no significant differences between TCs and the comparison group on posttreatment drug use, criminality, or depression. This report documents that short-term therapeutic communities can be successfully implemented in public shelters for homeless men.

Adolescent↗
PubMedDate not supplied

Hematological neoplasms with first presentation as spinal cord compression syndromes: a 10-year retrospective series and review of the literature.

CONTEXT: The epidural space is a well-known, albeit uncommon, location for lymphomatous involvement, estimated to occur in less than 3% of all systemic lymphomas. Initial presentation of the patient with disease in this site (i.e. primary spinal epidural lymphoma) has been considered to be "rare". When it has been reported, many studies have emphasized the occurrence of aggressive lymphomas with a poor prognosis. DESIGN: A 10-year retrospective search of our files generated 7 patients who presented initially with back pain, incontinence and/or lower extremity weakness, and by neuroimaging studies were found to have masses causing spinal cord compression syndromes necessitating neurosurgical intervention. RESULTS: The 7 patients included 4 males and 3 females with thoracic and lumbar epidural masses. Tumor types included high-grade non-Hodgkin lymphoma, B cell type (n = 4), indolent B cell lymphoma (n = 1), nodular sclerosing Hodgkin lymphoma (n = 1) and plasmacytoma (n = 1). Advanced disease (stage 4) was subsequently identified in all 7 patients. Despite this, survival varied greatly with therapy, from 3 weeks to almost 6 years, underscoring the need for correct classification of the lymphoma in order to optimize chemotherapeutic choices. The epidural space was the site of presentation of disease in 4% of all lymphomas diagnosed at our institution. CONCLUSIONS: Combining all reports in the literature, epidural presentation of lymphoma is not rare. Epidural lymphomas are distinct from both primary central nervous system lymphomas and from primary dural lymphomas. A broad range of systemic hematological tumor types can present as epidural masses. A full work-up for lymphoma classification may only be possible from the tissues received at the time of the neurosurgical decompression or biopsy procedure.

Adult↗
PubMedDate not supplied

Some home truths.

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Ill-Housed Persons↗