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Biomedical subjects

J J Nicholas

Publications and source records attributed to J J Nicholas.

At least 19 recordsLinked to original sources
PubMed2002

A genotypic association implicates myeloperoxidase in the progression of hepatic fibrosis in chronic hepatitis C virus infection.

The hepatitis C virus (HCV) is a major cause of liver disease and the complications of cirrhosis. Liver biopsies, performed prior to the development of liver cirrhosis, characteristically show an inflammatory cell infiltrate with varying degrees of fibrosis. Precisely how HCV infection induces hepatic fibrogenesis is unknown. Recent studies suggest the release of oxidants, cytokines and proteases from the host immune system are key to the development of fibrosis. Macrophages and neutrophils, cells heavily represented in the inflammatory cell response, contain the oxidant generating enzyme myeloperoxidase (MPO). Cellular levels of MPO can be influenced by a functional promotor polymorphism, -463G/A, which precedes the MPO gene. We examined the relationship between this MPO promotor genotype and the degree of fibrosis in 166 patients with chronic HCV infection. All patients had previously participated in clinical drug trials for the treatment of chronic HCV infection. The MPO genotype was determined from cryo-preserved lymphocytes obtained from patients prior to treatment. The degree of fibrosis was estimated from liver biopsy specimens obtained prior to treatment. We found that patients with the MPO GA/AA genotype were more likely to have advanced fibrosis scores compared with those with the GG genotype: Of the patients with GG genotype, 78% (79 of 102 cases) had lower Knodell Fibrosis scores of 0 or 1, compared to 56% (37 of 64 cases) of patients with GA/AA genotype (P < 0.05). The mechanism(s) by which MPO contributes to fibrosis progression remains to be determined.

Female↗
PubMed2001

A multifactorial study of age bias among rehabilitation professionals.

OBJECTIVES: To assess different dimensions of age bias among rehabilitation professionals and to determine the effect of patient gender and behavior on these biases. DESIGN: Between-subjects questionnaire study. SETTING: Randomly selected institutions accredited with the Commission on the Accreditation of Rehabilitation Facilities (CARF). PARTICIPANTS: Nine hundred seventy-four rehabilitation professionals from 9 disciplines at 23 CARF-accredited facilities. INTERVENTIONS: Each professional received a vignette case history of an amputation patient who varied in age (36yr, 76yr), gender (male, female), and patient behavior (ideal, depressed, noncompliant). The vignette was followed by the Professional Bias Questionnaire (PBQ), which included 25 questions assessing the professionals' responses to the patient. MAIN OUTCOME MEASURES: Main effects and interaction effects for age, gender, and behavior for the PBQ. RESULTS: Factor analysis of the PBQ questionnaire yielded 4 reliable scales: the professional's judgment of the patient's psychologic neediness, postdischarge potential, worthiness for rehabilitation, and their personal reaction to working with the patient. Analyses of variance resulted in significant age by behavior interaction effects for 3 of the 4 scales. Older patients were viewed more negatively than equivalent younger patients when they were noncompliant. Professionals also had a more negative personal reaction to depressed older patients compared with equivalent younger patients. In contrast, gender bias was only found in 1 specific situation and did not interact with age bias. CONCLUSION: Several forms of bias toward older adult patients were found among rehabilitation professionals, but they were present only when patient behavior was less than ideal. Age bias continues to be a critical issue in the equity of rehabilitation services and should be addressed with training and policy changes.

Adult↗
PubMed2000

The postpericardiotomy syndrome as a cause of pleurisy in rehabilitation patients.

Pleuritic chest pain in patients on a rehabilitation unit may be caused by several conditions. We report 2 cases of postpericardiotomy syndrome (PPS) as a cause of pleuritic pain. PPS occurs in 10% to 40% of patients who have coronary bypass or valve replacement surgery. The syndrome is characterized by fever, chest pain, and a pericardial or pleural friction rub. Its etiology is believed to be viral or immunologic. The syndrome can be a diagnostic challenge, and an increase in length of hospitalization because of it has been documented. Identified risk factors for PPS include age, use of prednisone, and a history of pericarditis. A higher incidence has been reported from May through July. Many patients undergo a battery of expensive procedures before PPS is diagnosed. The pain is sharp, associated with deep inspiration, and changes with position. Pleural effusions may be present and tend to occur bilaterally. Pericardial effusions are a documented complication. A pericardial or pleural rub may be present and is often transient. Serial auscultation is important. Laboratory work provides clues with a mild leukocytosis and an elevated erythrocyte sedimentation rate. However, this does not provide the definitive diagnosis. Cardiac enzymes are not reliably related to the syndrome. An electrocardiogram will show changes similar to those associated with pericarditis. The patient may have a fever, but it is rarely higher than 102.5 degrees F. Complications include pericardial effusions, arrhythmias, premature bypass graft closure, and cardiac tamponade. Treatment consists of a 10-day course of nonsteroidal anti-inflammatory drugs.

Aged↗
PubMed1998

The effect of lesions to cortical areas V4 or AIT on pupillary responses to chromatic and achromatic stimuli in monkeys.

We measured the pupillary response to achromatic and chromatic grating stimuli in left and right visual hemifields of two rhesus monkeys, who were trained to fixate the centre of a screen. After removing the rostral inferior temporal cortex of one hemisphere, the response to chromatically modulated gratings in the contralateral hemifield was abolished, whereas the response to the luminance modulated grating was unaffected. In one of the monkeys, in which area V4 of the other hemisphere was also removed, there was no effect on the pupillary response to either kind of grating presented in the hemifield contralateral to the V4 lesion. The results show that the cortical contribution to the response of the pupil to purely chromatic changes is mediated by rostral temporal cortex, not by area V4.

Animals↗
PubMed1998

"Naturalization" of the alien hand: case report.

The alien hand syndrome is an involuntary motor phenomenon that occurs infrequently and mostly in stroke patients. A case is reported of a 67-year-old man with left hemiparesis whose hand crept and crawled, especially at night, which caused him to awaken by grasping his collar. The disturbing nocturnal activity of the hand was stilled by placing it in a common oven mitt.

Aged↗
PubMed1998

Rehabilitation staff perceptions of characteristics of geriatric rehabilitation patients.

OBJECTIVE: To determine if professionals treating older rehabilitation patients regarded them as having different characteristics than younger rehabilitation patients, to derive factors from these perceptions, and to examine the impact of the discipline of the professional and other factors on these perceptions. DESIGN: Rehabilitation professionals at a random sample of facilities accredited by the Commission on Accreditation of Rehabilitation Facilities were surveyed to determine their level of agreement with 60 items addressing characteristics of older rehabilitation patients. The items were derived from focus groups with rehabilitation staff members. PARTICIPANTS: One thousand sixty-three rehabilitation professionals from nine disciplines (nursing, occupational therapy, physiatry, physical therapy, psychology, social work, speech pathology, therapeutic recreation, and vocational counseling) responded to the questionnaire and were included in the study. RESULTS: There was a wide range of agreement levels across the 60 items (range of median agreement, 12.7% to 93.5%). Factor analysis resulted in six categories of perceptions regarding older rehabilitation patients: (1) physical limitations, (2) motivational deficits, (3) psychological distress/need for support, (4) maturity and positive coping skills, (5) need for privacy/decreased adaptability, and (6) discharge complications. Significant differences across disciplines were found for five of six factors. Nurses agreed more strongly with the negative psychological factors (2, 3, and 5) compared to physical therapists, psychologists, and social workers. Physicians scored significantly higher than two other disciplines on the physical limitations factor. These differences may be related to the distinct role each discipline plays in the rehabilitation process. Older professionals also scored higher on four factors, likely because of personal rather than professional experience with aging. CONCLUSIONS: Treating professionals recognize differences between younger and older rehabilitation patients. Many of these perceived differences can be viewed as variables that require more effort and skill on the part of the treating professional. The training of rehabilitation professionals needs to better prepare individuals from all disciplines to adapt to age-specific differences.

Activities of Daily Living↗
PubMed1997

Anticipatory postural adjustments during standing in below-the-knee amputees.

OBJECTIVE: We studied the role of adaptive changes within the central nervous system in anticipatory postural adjustments seen in unilateral below-the-knee amputees. DESIGN: Changes in electromyographic and mechanical variables were compared during standardized tasks performed by standing subjects. BACKGROUND: Anticipatory postural adjustments represent an important mechanism of postural control which was expected to be changed in amputees because of both mechanical and secondary, neurological reasons. METHODS: Six patients after a below-the-knee amputation and six control subjects stood on a force platform and performed fast bilateral shoulder movements and also dropped or caught a load from (into) extended hands. Anticipatory changes in the background activity of postural muscles were analysed. RESULTS: In amputees, there were cases of marked asymmetry in anticipatory changes of the background muscle activity which were larger on the intact side of the body but were commonly small or absent on the side of the amputation. This asymmetry could lead to larger mediolateral forces and displacements of the centre of pressure. CONCLUSIONS: We suggest that asymmetrical patterns of anticipatory postural adjustments reflect central adaptive changes secondary to the amputation. Rehabilitation approaches would benefit from understanding and taking advantage of the adaptive changes within the central nervous system. RELEVANCE: We demonstrated asymmetries in patterns of anticipatory postural adjustments during voluntary arm movements and load manipulations by standing unilateral amputees. This finding is of potential importance for rehabilitation of amputees and their prosthetic training.

Journal Article↗
PubMed1996

Are there deficits in anticipatory postural adjustments in Parkinson's disease?

We studied anticipatory postural adjustments in patients with Parkinson's disease who dropped a load from extended arms while standing. Anticipatory postural adjustments were seen when load dropping was induced by a fast, bilateral shoulder abduction but not when it was induced by pressing a trigger with the right thumb. We conclude that anticipatory postural adjustments in patients with Parkinson's disease can change with the magnitude of an action which is used to trigger a predictable postural perturbation. Thus, the described deficits in anticipatory postural adjustments in patients with Parkinson's disease are likely to be of quantitative rather than qualitative nature.

Aged↗
PubMed1996

Contrast sensitivity in one-eyed subjects.

The effects of early monocular form deprivation on the developing mammalian visual system, and the anatomical and physiological consequences of early monocular enucleation, suggest that the remaining eye of human subjects who had the other eye removed early during development might be capable of supernormal performance. To test this inference, the achromatic contrast sensitivity of the remaining eye of subjects who had the other eye removed at different ages after birth was compared with that of normal subjects tested under monocular and binocular conditions. The results show that all subjects who had an eye removed during early development had a higher contrast sensitivity than the better eye of control subjects. Furthermore, the earlier in development that the eye was removed, the lower the spatial frequency at which contrast sensitivity is enhanced compared with measurements made in the better eye of control subjects, and the larger the range of spatial frequencies over which contrast sensitivity is supernormal.

Adolescent↗
PubMed1996

Bacterial discitis caused by limb gangrene requiring below-knee amputation.

Two patients presented with disabling back pain and were unable to participate in physical therapy activities after being admitted to an acute rehabilitation center. Both patients had bacterial discitis of the lumbar spine that was apparently caused by infected ischemic limb tissue, ultimately removed at below-knee amputation. The literature describes many cases of bacterial discitis infected from many sources, but not from ischemic limb tissue requiring subsequent amputation. Many such cases may exist, however, and earlier recognition of this condition will enable appropriate treatment before vertebral destruction and/or neurological sequelae.

Aged↗
PubMed1996

Paediatric urolithiasis in a remote Australian aboriginal community.

A retrospective study of Community Health Service patient records revealed 10 cases of urolithiasis in Aboriginal children under 5 years of age in a remote central Australian Aboriginal community over a 4 year period, out of a total under-5 population estimate of 62. The highest attack rate was in the 0-2 age group, where nearly one in 10 children presented per year. All children had significant associated morbidity. Two children underwent pyelolithotomy. Aboriginal children in the remote arid zone study community suffer exceptionally high rates of urolithiasis. Inadequate diet, dehydration and recurrent infectious disease are factors in pathogenesis. Further study may elucidate aetiology, but the implications of these data for improving environmental conditions and health service delivery in Aboriginal communities are urgent.

Age Distribution↗
PubMed1996

Behavioural and electrophysiological chromatic and achromatic contrast sensitivity in an achromatopsic patient.

OBJECTIVES: In cases of incomplete achromatopsia it is unclear whether residual visual function is mediated by intact striate cortex or results from incomplete lesions to extrastriate cortical visual areas. A patient with complete cerebral achromatopsia was tested to establish the nature of his residual vision and to determine the integrity of striate cortex function. METHODS: Behavioural contrast sensitivity, using the method of adjustment, and averaged visually evoked cortical potentials were measured to sinusoidally modulated chromatic and achromatic gratings in an achromatopsic patient and a normal observer. Eye movements were measured in the patient using a Skalar infrared monitoring system. RESULTS: The patient's chromatic contrast sensitivity was normal, indicating that despite his dense colour blindness his occipital cortex still processed information about spatial variations in hue. His sensitivity to achromatic gratings was depressed particularly at high spatial frequencies, possibly because of his jerk nystagmus. These behavioural results were reinforced by the nature of visually evoked responses to chromatic and achromatic gratings, in which total colour blindness coexisted with an almost normal cortical potential to isoluminant chromatic gratings. CONCLUSIONS: The results show that information about chromatic contrast is present in some cortical areas, and coded in a colour-opponent fashion, in the absence of any perceptual experience of colour.

Adult↗
PubMed1996

Motor control research in rehabilitation medicine.

Progress in rehabilitation medicine requires an understanding of the basic rules of motor coordination, as well as of the contribution of adaptive processes within the central nervous system to the patterns of impaired movements. We assume that patterns of voluntary movements reflect rules of coordination that are used by the intact central nervous system of healthy persons. In pathological conditions that may include cognitive, central neurological, and peripheral disorders, the central nervous system may reconsider these rules leading to different peripheral patterns of voluntary movements. In such conditions, changed motor patterns may be considered adaptive to a primary disorder. They may even be viewed as optimal for a given state of the system of movement production. We suggest that the emphasis of therapeutic approaches must be placed not on restoring the motor patterns to 'as close to normal as possible', but on assisting the central nervous system to develop optimal adaptive reactions to the original underlying problem.

Adaptation, Physiological↗
PubMed1995

Feedforward postural adjustments in a simple two-joint synergy in patients with Parkinson's disease.

Patients with Parkinson's disease, age-matched controls and young control subjects performed discrete elbow or wrist movements in a sagittal plane under the instruction to move one of the joints "as fast as possible." Relative stability of the other, postural joint was comparable in all 3 groups, while movement time was the highest in the patients and the lowest in young controls. Typically, EMG patterns in both muscle pairs acting at the joints demonstrated a commonly observed "tri-phasic" pattern. A cross-correlation analysis of the EMGs confirmed virtually simultaneous bursts in the wrist and elbow flexors and in the wrist and elbow extensors. In all 3 groups, there were no signs of anticipatory activation of postural muscles in about 90% of movements. We consider postural anticipation not a separate process, but a separate peripheral pattern of a single control process that may involve a number of joints and muscles. We conclude that the postural deficits in Parkinson's disease are not related to a basic deficit in the ability to generate feedforward postural adjustments but to other factors that may include the specificity of maintaining the vertical posture in the field of gravity.

Aged↗
PubMed1995

Anticipatory postural adjustments during self inflicted and predictable perturbations in Parkinson's disease.

This study investigated the relation between impaired anticipatory postural adjustments and bradykinesia in Parkinson's disease. Patients with Parkinson's disease and age matched controls stood on a platform. In one series of experiments, they performed fast, discrete shoulder flexion or extension movements. In another series, they were required to press a trigger with the right thumb and thus to release a load that was suspended from a bar which they were holding in front of them in extended arms. One more series included catching a load on the same bar. Anticipatory changes in the activity of postural muscles before fast voluntary movements occurred in patients and controls although the patients showed higher variability of anticipatory patterns. During load dropping and catching, control subjects had reproducible, although smaller, anticipatory changes in postural muscle activity. Such changes were absent in all but one patient. Two sources of these postural perturbations were analysed. The anticipatory postural adjustments in different muscle groups may counteract perturbations of different origin. The distal to proximal sequencing of joint involvement in postural reactions may be related to different reference points and working points associated with these tasks compared with reaching limb movements. The deficit in anticipatory postural adjustments in Parkinson's disease is likely to be unrelated to bradykinesia and is more likely to reflect the deficits in the basic processes of preparation and initiation of a motor act.

Aged↗
PubMed1994

The quality of life after orthotopic liver transplantation: an analysis of 166 cases.

We surveyed by questionnaire 346 patients who underwent orthotopic liver transplantation to determine their postoperative status. One hundred sixty-six patients returned the questionnaires, which were administered at least 12 months after the transplants. Universally, the patients could perform necessary activities of daily living, but 36.7% noted some extremity weakness, 18.1% noted pain in an extremity, and 40.4% noted "arthritis." Of the respondents, 41.3% rode a bike often, 28.4% swam, and endurance improved from 43.9% severely affected to 8.0% severely affected. Posttransplant employment was related to marital status (3.18 times more likely to be employed if married); duration of liver disease with patients having the disease more than 2 years 3.22 times more likely to be employed. Patients without pain, weakness, or arthritis were 7.8 times more likely employed. The exact nature of the musculoskeletal complaints remains to be defined.

Activities of Daily Living↗