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Biomedical subjects

J Whyte

Publications and source records attributed to J Whyte.

At least 19 recordsLinked to original sources
PubMed2005

Neuropsychological outcome and community re-integration following traumatic brain injury: the impact of frontal and non-frontal lesions.

PRIMARY OBJECTIVE: To examine the relationship between cortical lesion location and brain injury outcome. It was hypothesized that focal frontal lesions after traumatic brain injury (TBI) would result in decreased executive and memory functioning and poor community participation outcome. RESEARCH DESIGN: Three quasi-experimental, prospective studies employed a total of 643 patients with focal frontal, fronto-temporal, non-frontal or no lesions in CT scans. METHODS AND PROCEDURES: CT scan analysis, neuropsychological assessment, the Neurobehavioural Functioning Inventory (NFI), the Community Integration Questionnaire (CIQ). MAIN RESULTS: In study 1, frontal and fronto-temporal groups performed worse in executive functioning and better in constructional ability. Study 2 found no differences in neuropsychological and community re-integration measures at 1-year follow-up. Study 3 found comparable neuropsychological test score improvement across groups over 1 year. CONCLUSIONS: Results are consistent with previous findings and document the potential for test score improvement with rehabilitation and suggest that lesion location needs to be considered when individual rehabilitation plans are being implemented in the post-acute stage of TBI.

Accidental Falls↗
PubMed2004

Hemispatial neglect: Subtypes, neuroanatomy, and disability.

OBJECTIVE: To assess the relative frequency of occurrence of motor, perceptual, peripersonal, and personal neglect subtypes, the association of neglect and other related deficits (e.g., deficient nonlateralized attention, anosognosia), and the neuroanatomic substrates of neglect in patients with right hemisphere stroke in rehabilitation settings. METHODS: The authors assessed 166 rehabilitation inpatients and outpatients with right hemisphere stroke with measures of neglect and neglect subtypes, attention, motor and sensory function, functional disability, and family burden. Detailed lesion analyses were also performed. RESULTS: Neglect was present in 48% of right hemisphere stroke patients. Patients with neglect had more motor impairment, sensory dysfunction, visual extinction, basic (nonlateralized) attention deficit, and anosognosia than did patients without neglect. Personal neglect occurred in 1% and peripersonal neglect in 27%, motor neglect in 17%, and perceptual neglect in 21%. Neglect severity predicted scores on the Functional Independence Measure and Family Burden Questionnaire more accurately than did number of lesioned regions. CONCLUSIONS: The neglect syndrome per se, rather than overall stroke severity, predicts poor outcome in right hemisphere stroke. Dissociations between tasks assessing neglect subtypes support the existence of these subtypes. Finally, neglect results from lesions at various loci within a distributed system mediating several aspects of attention and spatiomotor performance.

Activities of Daily Living↗
PubMed2004

Patterns of spontaneous recovery of neglect and associated disorders in acute right brain-damaged patients.

OBJECTIVES: The evolutionary pattern of spontaneous recovery from acute neglect was studied by assessing cognitive deficits and motor impairments. Detailed lesion reconstruction was also performed to correlate the presence of and recovery from neglect to neural substrates. METHODS: A consecutive series of right brain-damaged (RBD) patients with and without neglect underwent weekly tests in the acute phase of the illness. The battery assessed neglect deficits, neglect-related deficits, and motor impairment. Age-matched normal subjects were also investigated to ascertain the presence of non lateralised attentional deficits. Some neglect patients were also available for later investigation during the chronic phase of their illness. RESULTS: Partial recovery of neglect deficits was observed at the end of the acute period and during the chronic phase. Spatial attention was impaired in acute neglect patients, while non spatial attentional deficits were present in RBD patients with and without acute neglect. A strong association was found between acute neglect and fronto-parietal lesions. Similar lesions were associated with neglect persistence. In the chronic stage, neglect recovery was paralleled by improved motor control of the contralesional upper limb, thus emphasising that neglect is a negative prognostic factor in motor functional recovery. CONCLUSIONS: These findings show that spatial attention deficits partially improve during the acute phase of the disease in less than half the patients investigated. There was an improvement in left visuospatial neglect at a later, chronic stage of the disease, but this recovery was not complete.

Acute Disease↗
PubMed2002

The minimally conscious state: definition and diagnostic criteria.

OBJECTIVE: To establish consensus recommendations among health care specialties for defining and establishing diagnostic criteria for the minimally conscious state (MCS). BACKGROUND: There is a subgroup of patients with severe alteration in consciousness who do not meet diagnostic criteria for coma or the vegetative state (VS). These patients demonstrate inconsistent but discernible evidence of consciousness. It is important to distinguish patients in MCS from those in coma and VS because preliminary findings suggest that there are meaningful differences in outcome. METHODS: An evidence-based literature review of disorders of consciousness was completed to define MCS, develop diagnostic criteria for entry into MCS, and identify markers for emergence to higher levels of cognitive function. RESULTS: There were insufficient data to establish evidence-based guidelines for diagnosis, prognosis, and management of MCS. Therefore, a consensus-based case definition with behaviorally referenced diagnostic criteria was formulated to facilitate future empirical investigation. CONCLUSIONS: MCS is characterized by inconsistent but clearly discernible behavioral evidence of consciousness and can be distinguished from coma and VS by documenting the presence of specific behavioral features not found in either of these conditions. Patients may evolve to MCS from coma or VS after acute brain injury. MCS may also result from degenerative or congenital nervous system disorders. This condition is often transient but may also exist as a permanent outcome. Defining MCS should promote further research on its epidemiology, neuropathology, natural history, and management.

Humans↗
PubMed2002

Morphometric study of testis of Wistar rat after open-ended vasectomy.

The effects on the testis of open-ended vasectomy in the Wistar rat have been assessed morphometrically and evaluated statistically at 1, 4, 12, and 24 weeks after operation, and compared to those in sham-operated controls. The open-ended technique, ie, without ligation of the epididymal end of the cut ductus deferens, allowed drainage of sperm into the spermatic cord. During the period of our study, it did not affect the structure of the testis; although the germinal epithelium, basement membrane, and the stroma and cells of the interstitial space all showed variations when compared to the control group, these were not statistically significant.

Animals↗
PubMed2001

Prediction of functional outcomes after traumatic brain injury: a comparison of 2 measures of duration of unconsciousness.

OBJECTIVE: To compare the usefulness of time until motor localization occurs versus time until commands are followed in predicting outcome after traumatic brain injury (TBI). DESIGN: A retrospective analysis of data from a prospective cohort study of subjects with severe TBI. SETTING: Seventeen Traumatic Brain Injury Model System programs. PARTICIPANTS: A total of 496 subjects, recruited through the TBI Model System programs, with loss of consciousness greater than 1 day, with no late neurosurgical complications, and complete data for all measures. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Time until Glasgow Coma Scale (GCS) motor score of 5 (time to motor localization) and time until GCS motor score of 6 (time until commands were followed) were abstracted from medical records. Functional outcomes were assessed at inpatient rehabilitation admission and discharge, along with acute and rehabilitation lengths of stay and charges. RESULTS: Time until commands were followed was a better predictor of all of the outcomes assessed than time until motor localization occurred. In multiple regression models, time until motor localization did not add significantly to the prediction provided by time until commands were followed. The predictive power of time to command following was superior even in the subgroup with poor language comprehension as measured by the Token Test. CONCLUSION: Despite the theoretical appeal of time to motor localization (eg, in persons with language comprehension problems), time to command following appears to be a more powerful predictor of outcome after severe brain injury.

Adult↗
PubMed2001

Long-term causes of death after traumatic brain injury.

OBJECTIVE: To determine which causes of death are more frequent in persons with traumatic brain injury (TBI), and by how much, compared with the general population. Our focus was the period beginning 1 yr after injury. DESIGN: Subjects were 2320 Californians with long-term mental disability after a TBI at age 10 yr or more, followed up between 1988 and 1997. The units of study were person-years, each linked to the subject's age, gender, level of ambulation, time since injury, and cause of death (if any) for the specific year. Observed numbers of cause-specific deaths were compared with numbers expected according to general population mortality rates. RESULTS: Mortality was higher between 1.0 and 5.0 yr postinjury than after 5.0 yr and was strongly related to reduced mobility. Death rates were elevated for circulatory diseases, respiratory diseases, choking/suffocation, and seizures, with seizure deaths being relatively frequent, even among the most ambulatory. CONCLUSIONS: Death rates for several causes are elevated in persons with long-term sequelae of TBI. The increased risk of choking/suffocation should be of interest to caregivers. Life expectancy seems to be reduced, even for patients who are fully ambulatory.

Activities of Daily Living↗
PubMed2001

Contribution to the development of the stapedius muscle structure in human fetuses.

The purpose of this report is to contribute to the knowledge of the morphogenesis of the human stapedius muscle. We have studied the stapedius structure development in 17 temporal bones from human fetuses. Chronological ages were from 48 days (21 mm) to 29 weeks (270 mm). Samples were fixed in 10% formol, decalcified with 2% nitric acid, embedded in Paraplast, sectioned in sequence of 7 microns and were stained with haematoxylin & eosin and Martins' trichrome. Four maturation stages were observed in the development of the stapedius muscle structure. First, the formation of the 'primordium muscularis' in the mesenchyme of the tympanic cavity (promyoblasts) was observed in a 36-mm embryo. Second, its differentiation into myoblasts, and its next cellular fusion to form muscle tubes, was seen in a 99-mm foetus. In the third stage, myofibrogenesis phenomena were developed, to synthesize, the myotube myoblasts, myofilaments, phenomena we observed that took place during the 14th to 17th weeks of development. The last stage was characterized by the presence of striated muscle fibres, at first intermingled with myotubes (18th to 26th weeks), until in the 29th week fetuses (270 mm) the skeletal muscle fibre was completely differentiated. We conclude that in the 29th week of development (270 mm) the stapedius muscle structure is completely differentiated, although the functional development is not complete until birth.

Embryonic and Fetal Development↗
PubMed2000

MHC class II associations with autoantibody and T cell immune responses to the scleroderma autoantigen topoisomerase I.

Topoisomerase I (topo I) is a major autoantigen recognized by autoantibodies in about 30% of sera from patients with systemic sclerosis (SSc). Certain HLA-DRB1 and HLA-DQB1 alleles have been reported to be associated with autoantibody and T-cell responses to topo I suggesting a T-cell dependent process. We have examined the MHC class II allele associations with anti-topo I antibodies in 16 patients with SSc compared to 250 healthy controls. Furthermore, we have studied the T cell responses to a recombinant full-length topo I molecule purified from a baculovirus expression system in eight patients with SSc and eight controls (five healthy and three with autoimmune disease). HLA-DR5 was significantly increased in patients with anti-topo I antibodies (P< 0.02). Proliferative peripheral blood mononuclear cell (PBMC) responses to soluble topo I were present in nine of 16 individuals (four of eight with SSc and five of eight controls), including the three SSc patients with anti-topo I antibodies. Homozygosity for HLA DQB1:30:Y alleles was present in five of nine responders (P< 0.03) compared to none of the non-responders. Our findings support the notion that the MHC class II background influences the ability to generate an autoimmune response to intracellular autoantigens to which the immune system may not have been tolerized. Additional factors associated with the generation of autoantibodies appear to be more intimately associated with the development of SSc.

Alleles↗
PubMed2000

The relation between lower extremity strength and shoulder overuse symptoms: a model based on polio survivors.

OBJECTIVE: To determine the relation between lower extremity weakness and shoulder overuse symptoms among polio survivors. We predicted that individuals with moderate weakness in their leg extensor muscles would use their arms to help compensate for this weakness and would be at high risk for developing symptoms of shoulder overuse. DESIGN: A cohort study of polio survivors recruited from the Einstein-Moss Postpolio Management Program (Philadelphia), the community, and the surrounding region. SETTING: A research laboratory at Moss Rehabilitation Research Institute, Philadelphia, PA. PARTICIPANTS: One hundred ninety-four polio survivors. Demographic and medical history data, symptom data, and strength data were obtained for each. MAIN OUTCOME MEASURES: Presence or absence of shoulder symptoms and ratings of pain by visual analogue scale were recorded. Strength was measured using a hand-held dynamometer and manual muscle testing. RESULTS: Shoulder symptoms could be grouped into two distinct clusters based on the type of testing used for assessment. Symptoms elicited by palpation were present in 26% of the subjects and were strongly related to knee extensor strength and weight. These symptoms were more common among women than men (42% and 10%, respectively). Symptoms elicited by resistance tests were present in 33% of the subjects and were seen with equal frequency in both sexes. These symptoms were also related to lower extremity strength, but the specific relationship was not as clear as for the palpation-related symptoms. CONCLUSIONS: Lower extremity weakness predisposes individuals to shoulder overuse symptoms. Sex and body weight are contributing factors. These results may be generalized to other populations with lower extremity weakness, including the elderly.

Adult↗
PubMed2000

Frequency and duration of inattentive behavior after traumatic brain injury: effects of distraction, task, and practice.

Traumatic brain injury (TBI) is associated with impairments of attention, most typically measured through tests of information processing, or by subjective symptom endorsement by patients, families, and clinicians. We have previously shown increased rates of off-task behavior among patients with TBI versus controls as defined by videotaped records of independent work in distracting environments. In this research, we report on a more detailed method of coding such videotaped records which allows measurement of the precise number of off-task behaviors, their durations, and their relationship to distracting events. Using this method, we studied 20 patients with recent moderate-to-severe TBI and 20 demographically comparable controls as they performed independent work tasks while being subjected to controlled distracting events. This research confirms that patients are markedly less attentive than controls both in the presence of distractions and in their absence, that distractions have an influence on off-task behavior in both groups, and that the disruptive impact of distractors wanes relatively quickly for controls but not for patients. The duration of distraction produced by various classes of distracting events appeared similar for patients and controls, although the power to detect differences in behavioral duration between groups was limited. The pattern of inattentiveness among patients showed minimal relationship to measures of injury severity within this sample.

Adolescent↗
PubMed2000

Phagocytosis of mycobacteria by U937 cells: a rapid method for monitoring uptake and separating phagocytosed and free bacteria by magnetic beads.

A human-derived monocytic cell line (U937) was induced to phagocytose Mycobacterium phlei by the addition of phorbol myristate acetate (PMA) to the culture medium for 50-60 h. Cells not treated with PMA were unable to phagocytose M. phlei. Magnetic beads enabled a rapid and highly efficient separation of phagocytosed and free bacteria to be achieved, an approach which is particularly useful if colony plating is used to enumerate bacterial survival within phagocytic cells. Fluorescence-activated cell sorting (FACS) analysis showed that 98% of U937 cells contained viable bacteria after 3 h.

Cell Separation↗
PubMed2000

Changes in strength over time among polio survivors.

OBJECTIVE: To study changes in the strength of different muscle groups in polio survivors over a period of approximately 9 months. DESIGN: Longitudinal study. SETTING: Moss Rehabilitation Research Institute. PARTICIPANTS: One hundred twenty subjects (57 men, 63 women) were studied on three occasions, each 3 to 5 months apart. Subjects were recruited through the Einstein-Moss Post-Polio Management Program. newspaper advertisements, and polio support groups. MAIN OUTCOME MEASURES: Isometric strength of 30 muscle groups (16 in upper extremities, 14 in lower extremities) was measured, using a hand-held dynamometer. RESULTS: Data were analyzed in two separate groups: upper-extremity muscles and lower-extremity muscles. Results for the upper-extremity muscles revealed evidence of a significant deterioration in strength. The amount of deterioration differed among muscles and increased with age. There was also evidence of deterioration in strength in the flexor muscles in the ankle, hip, and knee. However, the rate of deterioration in these muscles was not strongly related to age, time since polio, gender, symptom status, or history of residual weakness. CONCLUSIONS: Strength is deteriorating among polio survivors at a rate higher than that associated with normal aging. This deterioration is not occurring in the extensor, or so-called "weight-bearing" muscles, but is occurring in many of the upper-extremity muscle groups and in the flexor muscles in the lower extremities.

Adult↗
PubMed2000

Elastin variations implicating in vascular smooth muscle cells phenotype in human tortuous arteries.

The aim of the present work was to study the morphological implications between the elastin and the phenotypic expression of the vascular smooth muscle cells. For this purpose, sixty human tortuous arteries from different territories have been studied. We have measured the morphometric indexes Intimal Thickening Index and Elastolyse Index and they have been quantified with computer system analysis, image-colour corresponding to the orcein and Verhoëff reactions for detecting elastin and the alpha-actin in the smooth muscle cells. We compared both territorial arteries from the cranial and from abdominal origin. The elastin concentration was similar in both territories, but not its morphology according to its spatial distribution. We have observed a relationship between the elastin structural organisation from the media of arteries and of the internal elastic lamina in these territories and the variation of reactivity to the smooth muscle alpha-actin as a marker of the phenotypic state. Our results confirm the hypothesis that elastin, besides intervening in the architecture of the arterial wall, is a factor implicated in the phenotypic variability of the smooth muscle cells and in the development and evolution of the intimal thickenings in human atherosclerosis.

Adult↗
PubMed1999

An international study to assess reliability of the Migraine Disability Assessment (MIDAS) score.

BACKGROUND: The Migraine Disability Assessment (MIDAS) instrument is a five-item questionnaire developed to measure headache-related disability and improve doctor-patient communication about the functional consequences of migraine. OBJECTIVES: To examine the test-retest reliability and internal consistency of the five items and of the overall MIDAS score in population-based samples of migraine sufferers in two countries and to compare consistency across countries. METHODS: Using a clinically validated telephone interview, population-based samples of migraine-headache sufferers were identified in the United States (Baltimore, MD) and the United Kingdom (Merton and Sutton, Surrey). Eligible individuals completed the MIDAS questionnaire on two occasions an average of 3 weeks apart. The MIDAS score is derived from five questions about missed time from work and household work (one question each about missed days and days with at least 50% reduced productivity) and missed days of nonwork activities. RESULTS: A total of 97 migraine-headache sufferers from the United States and 100 from the United Kingdom completed the MIDAS questionnaire twice. Mean and median item values and overall MIDAS scores were similar between the United States and the United Kingdom. Test-retest Spearman correlations of individual items ranged from 0.46 to 0.78. No significant differences in item-specific correlations were observed between the United States and United Kingdom. The test-retest Pearson correlation of the MIDAS score (i.e., sum of lost days and reduced-effectiveness days in each domain) was 0.80 in the United States and 0.83 in the United Kingdom. The Cronbach alpha, a measure of internal consistency, was 0.76 in the United States and 0.73 in the United Kingdom. CONCLUSIONS: This is the first international population-based study to assess the reliability of a disability-related illness severity score for migraine. The reliability and internal consistency of the Migraine Disability Assessment score are similar to that of a previous questionnaire (Headache Impact Questionnaire). However, the Migraine Disability Assessment score requires fewer questions, is easier to score, and provides intuitively meaningful information on lost days of activity in three domains.

Adolescent↗