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Biomedical subjects

S Mercer

Publications and source records attributed to S Mercer.

At least 19 recordsLinked to original sources
PubMed2000

Biomechanics of the cervical spine. I: Normal kinematics.

UNLABELLED: This review constitutes the first of four reviews that systematically address contemporary knowledge about the mechanical behavior of the cervical vertebrae and the soft-tissues of the cervical spine, under normal conditions and under conditions that result in minor or major injuries. This first review considers the normal kinematics of the cervical spine, which predicates the appreciation of the biomechanics of cervical spine injury. It summarizes the cardinal anatomical features of the cervical spine that determine how the cervical vertebrae and their joints behave. The results are collated of multiple studies that have measured the range of motion of individual joints of the cervical spine. However, modern studies are highlighted that reveal that, even under normal conditions, range of motion is not consistent either in time or according to the direction of motion. As well, detailed studies are summarized that reveal the order of movement of individual vertebrae as the cervical spine flexes or extends. The review concludes with an account of the location of instantaneous centres of rotation and their biological basis. RELEVANCE: The fact and precepts covered in this review underlie many observations that are critical to comprehending how the cervical spine behaves under adverse conditions, and how it might be injured. Forthcoming reviews draw on this information to explain how injuries might occur in situations where hitherto it was believed that no injury was possible, or that no evidence of injury could be detected.

Atlanto-Axial Joint↗
PubMed1999

The ligaments and annulus fibrosus of human adult cervical intervertebral discs.

STUDY DESIGN: Descriptive, microdissection study. OBJECTIVE: To determine the morphology of the human adult cervical intervertebral disc and its ligaments. SUMMARY OF BACKGROUND DATA: Some studies indicate that the cervical disc is distinctly different from the lumbar intervertebral disc, yet most clinical and anatomic texts appear content with extrapolating data from the lumbar spine. A detailed three-dimensional description of the cervical intervertebral disc and its surrounding ligaments is currently unavailable. METHODS: Whole cervical spinal columns were freed from 12 human adult embalmed cadavers, and the posterior elements and soft tissues were removed. Using microdissection, the longitudinal ligaments and the fibrous components of 59 cervical intervertebral disc were resected systematically. The orientation, location, and attachments of each stripped bundle of collagen were recorded photographically and in sketches. RESULTS: The cervical anulus fibrosus does not consist of concentric laminae of collagen fibers as in lumbar discs. Instead, it forms a crescentic mass of collagen thick anteriorly and tapering laterally toward the uncinate processes. It is essentially deficient posterolaterally and is represented posteriorly only by a thin layer of paramedian, vertically orientated fibers. The anterior longitudinal ligament covers the front of the disc, and the posterior longitudinal ligament reinforces the deficient posterior anulus fibrosus with longitudinal and alar fibers. CONCLUSIONS: The three-dimensional architecture of the cervical anulus fibrosus is more like a crescentic anterior interosseous ligament than a ring of fibers surrounding the nucleus pulposus.

Adult↗
PubMed1999

Enabling and empowering certified nursing assistants for quality dementia care.

Currently, 1.2 million full-time equivalent employees (FTEs) care for more than 1.5 million residents in nursing homes where 75% of residents have dementia. By the year 2010, the number of residents in these institutions may double. Registered nurses (RNs) make up less than 7% of a home's total FTEs. In contrast, certified nursing assistants (CNAs) account for more than 40% of total FTEs. Thus, CNAs serve as the primary caregivers in nursing homes. Typically, CNAs have a high school education or less, and receive little more than minimum wage. Their extensive contact with residents has a tremendous impact on quality of life, but significant barriers limit their caregiving effectiveness. These barriers include poor pay, minimal long-term benefits, and insufficient training, recognition and support for their physically and emotionally labor-intensive care. This paper addresses the issues of training CNAs for dementia care by suggesting an organizational framework within which to view dementia training; providing an overview of barriers to empowering CNAs to provide quality care to dementia residents; reviewing research that has addressed a specific barrier; making recommendations for future research; and suggesting research approaches to address these recommendations.

Aged↗
PubMed1998

Nonpharmacological treatment for migraine: incremental utility of physical therapy with relaxation and thermal biofeedback.

The identification of musculoskeletal abnormalities in headache patients has led to the incorporation of physical therapy (PT) into treatment programs for chronic headache. The current studies: (i) investigated the efficacy of PT as a treatment for migraine, and (ii) investigated the utility of PT as an adjunct treatment in patients who fail to improve with relaxation training/thermal biofeedback (RTB). PT alone is not effective in reducing headache, with only 14% of subjects reporting significant headache reduction (mean reduction of 15.6% in comparison with 41.3% in RTB). However, PT may have been a useful adjunct, with 47% of a group of 11 subjects who had failed to improve with RTB reporting improvement with the addition of PT. It is recommended that RTB remain the nonmedical treatment of choice for migraine, and that PT may be a useful adjunct for patients who fail to improve after such treatment.

Adolescent↗
PubMed1994

Differences between American Indian and non-Indian children referred for psychological services.

The physical and social characteristics of 60 American Indian children referred for psychological services were compared to those of 60 matched, non-Indian controls. Data were obtained from detailed records available in a multidisciplinary, medical school-related child study clinic. Indian children exhibited more health and social risk factors, but were superior to non-Indians on a variety of motor variables. Interpretations are offered concerning better psychological services for American Indian children based on better understanding of their possible exposure to physical health and social risks which may be related to psychological development.

Adolescent↗
PubMed1993

Prevalence of canine distemper antibodies in the pagetic population.

Recent molecular evidence has implicated canine distemper virus (CDV) as a possible aetiologic agent in Paget's disease. However, previous serological studies have shown no differences in levels of anti-CDV antibodies between Paget's patients and controls. In this study, the technique of enzyme linked immunosorbent assay was used to measure anti-CDV antibodies in a group of Paget's patients from the North West of England. Some patients were undergoing treatment with 3-amino-hydroxypropylidene (APD), and the pre-treatment levels of antibody were compared with those following treatment. With several patients, it was also possible to compare the antibody levels with results from in situ hybridisation studies. No significant difference was found between the levels of anti-CDV antibodies in patients and controls. However, several patients and some of the controls did have markedly elevated levels of anti-CDV antibody. Antibody levels remained fairly constant following treatment with APD, except for two patients who showed marked changes. The patients positive for CDV by in situ hybridisation had significantly lower levels of anti-CDV antibodies when compared with those that were negative by in situ hybridisation. These results suggest that if CDV does cause Paget's disease, anti-CDV antibodies play little or no part in the disease pathogenesis. High levels of anti-CDV antibodies in both Paget's patients and controls suggest that a canine virus can infect humans. The fact that those patients that had CDV transcripts detectable in their bone cells had low levels of anti-CDV antibodies might suggest failure to clear the virus during an initial infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Intra-articular inclusions of the cervical synovial joints.

Two hundred and ten cervical synovial joints from 15 adult vertebral columns were studied by dissection to determine the form, dispositions and prevalence of intra-articular inclusions. Three types of inclusions were found. Fat pads occurred regularly in the atlanto-occipital joints but rarely in the zygapophysial joints. Capsular rims occurred occasionally at all levels. Fibro-adipose meniscoid occurred regularly in the atlanto-axial and zygapophysial joints. The function of fibroadipose meniscoids seems to be to protect the articular cartilages in gliding joints that subluxate during normal movement. Arguments are raised that these structures may act as a nidus for intra-articular fibrosis, and that meniscus extrapment may be a mechanism for torticollis.

Adipose Tissue↗
PubMed1991

Multiple paternity in wild common shrews (Sorex araneus) is confirmed by DNA-fingerprinting.

We have tested for the occurrence of multiple paternity in wild common shrews by karyotypic analysis and DNA-fingerprinting of five wild-caught females and their litters. Karyotypic data suggest that some litters were sired by more than one male, but provide no definitive evidence. By using DNA-fingerprinting, it was possible to establish that two males sired the litter of two females. The present report shows that multiple paternity is not a rare phenomenon in the common shrew and by using DNA-fingerprinting it is possible to assign individual offspring to different male parents even when none of the putative fathers are available for inspection.

Animals↗
PubMed1991

Caring for the cognitively impaired. Reconceptualizing disability and rehabilitation.

Rehabilitative interventions must be based on remaining cognitive and physical abilities while recognizing the presence of disabilities. Rehabilitation goals should be to provide the least restrictive environment using the least restrictive intervention, thus promoting independence. The use of behavioral strategies that support remaining abilities and compensate for cognitive deficits is recommended as a rehabilitative approach. The behavioral approach requires an assessment of the ADL steps, the range of activities a person is able to complete, and the kinds of caregiver assistance needed.

Activities of Daily Living↗
PubMed1991

Dressing for success. Promoting independence among cognitively impaired elderly.

In demented persons, activities of daily living skills may deteriorate more quickly than their cognitive decline warrants because caregivers do not allow them to perform ADLs to the full extent of their abilities. Caregiver actions that promote independent behaviors were used with subjects in home and nursing home settings. Four of five home subjects showed decreased caregiver assistance and increased ability to dress more independently. Although nursing home subjects did not show a decrease in caregiver assistance, observation showed that some nursing home caregivers did incorporate behavioral strategies, suggesting potential clinical efficacy of the strategies.

Activities of Daily Living↗
PubMed1988

Paradoxical intention and anti-exposure in a non-compliant, obsessive-compulsive ritualiser.

A woman with persistent obsessive-compulsive rituals showed limited improvement with exposure therapy, because of her refusal to comply fully with treatment and a lack of homework practice. She was negativistic towards therapists. Following a relapse, she was asked to try anti-exposure and to increase rituals. Paradoxically, this led to marked self exposure to the feared situation, and self-imposed response prevention, with resultant improvement, whereas anti-exposure instructions are generally anti-therapeutic in obsessive-compulsive disorder.

Adult↗
PubMed1988

Gastroschisis: ultrasonographic diagnosis, perinatal embryology, surgical and obstetric treatment and outcomes.

The embryology and onset time of gastroschisis are poorly understood. This paper reviews 22 cases of the condition seen at the Children's Hospital of Eastern Ontario between 1975 and 1986. Sixteen cases were judged to be of the perinatal and 6 of the early type. Ultrasonography revealed the actual time of development in one case and the probable time in another. In 20 cases the defect was closed primarily and in 2 by a staged procedure (Silon pouch). Nineteen infants (86.4%) survived. In all cases the umbilical vasculature was normal and all were right-sided. Other anomalies were rare and less important. Two clear examples of rupture of the umbilical ring are documented. Ultrasonography had been performed in 10 infants, usually for intrauterine growth retardation, and gastroschisis was diagnosed in 4 of these. Delivery was by cesarean section in six. Marked meconium staining occurred in 16 (73%), 7 of whom had subglottic aspiration of meconium. The average birth weight was 2480 g. Ultrasonography is recommended in all cases of intrauterine growth retardation with careful examination of the umbilical area to establish the presence and time of onset of gastroschisis. Vaginal delivery appears to be the route of choice for delivery.

Abdominal Muscles↗
PubMed1986

Insertion and deletion mutants of vaccinia virus.

Thirteen viable insertion mutants of vaccinia virus have been constructed. These mutants, containing coding sequences of the herpes simplex virus thymidine kinase (HSV-TK) gene, were generated by marker transfer via in vivo recombination. The mutants were identified using a replica filter plating technique by in situ hybridization using 32P-nick translated HSV-TK sequences and obtained as pure cultures by repeated plaque purification. Some of these insertion mutants were in turn used as substrates to generate viable deletion mutants of vaccinia virus in the presence of 5'-bromodeoxyuridine. An example of this approach resulting in a vaccinia virus deleted of approximately 1.5 kb of nonessential DNA is presented. Furthermore, the analysis of spontaneously occurring viable deletion mutants of vaccinia lacking approximately 21.4 kb of nonessential DNA is described.

Animals↗
PubMed1986

Nocturnal penile tumescence and serum testosterone levels.

Ten patients with chronic epilepsy were selected; five had high and five had low total serum testosterone levels. Each patient slept for two nights in the sleep laboratory. EEG monitoring and measurements of nocturnal penile tumescence were carried out during sleep. A clear relationship between both total and free serum testosterone levels were found with nocturnal penile tumescence. FSH, LH, SHBG, and prolactin showed no relationship. The five patients with low serum testosterone levels all showed reduced sexual activity.

Adolescent↗