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Biomedical subjects

W A Nix

Publications and source records attributed to W A Nix.

At least 19 recordsLinked to original sources
PubMed2004

Failure to detect enterovirus in the spinal cord of ALS patients using a sensitive RT-PCR method.

OBJECTIVE: To assess the association of enteroviruses (EV) with ALS by applying a sensitive seminested reverse transcription (RT) PCR protocol to the detection of enteroviral RNA in a blinded set of archived tissues from ALS and control cases. METHODS: The specimen set consisted of 24 frozen spinal cord samples from ALS cases, 17 frozen spinal cord samples from negative control (non-ALS) cases, and 5 frozen spinal cord positive control samples. The positive controls were two human spinal cord samples spiked with poliovirus (PV) and three spinal cords from PV-infected transgenic mice. A sensitive, EV-specific, seminested RT-PCR assay was used to detect EV genome in RNA extracted from the specimens and controls. RESULTS: The assay detected EV RNA in a 10(-5) dilution of infected mouse tissue. EV RNA was not detected in the ALS specimens or in specimens from control cases, despite the presence of amplifiable RNA as assessed by amplification with control primers, whereas all of the positive control specimens yielded the expected PV amplification product. CONCLUSION: The reported association between EV infection and ALS was not confirmed by testing this set of specimens with these sensitive methods.

5' Untranslated Regions↗
PubMed2003

Observer independent analysis of cerebral glucose metabolism in patients with chronic fatigue syndrome.

OBJECTIVES: To evaluate cerebral glucose metabolism, assessed by 18-fluorodeoxyglucose positron emission tomography (FDG-PET), in patients with chronic fatigue syndrome (CFS), using an observer independent analytical approach; and to characterise any observed alterations by correlating them with neuropsychological deficits. METHODS: 26 patients (13 female, 13 male) were examined. They all fulfilled the CDC diagnostic criteria for CFS. Their ages ranged from 26 to 61 years (mean (SD) age, 43 (9.3) years). They underwent extensive psychometric testing including the hospital anxiety and depression scale (HADS) and the short form 36 item health questionnaire (SF-36). Brain FDG-PET was done in all the subjects. After stereotactic normalisation, single subject comparisons with an age and sex matched normal database (n = 18) and a group comparison between the patients and normal controls were undertaken, along with additional correlation analyses between brain metabolism and psychometric test scores. RESULTS: 12 of the 26 patients showed no significant decrease in FDG uptake compared with the controls. Of the remaining 14, 12 showed hypometabolism bilaterally in the cingulate gyrus and the adjacent mesial cortical areas. Five of these 12 patients also had decreased metabolism in the orbitofrontal cortex. The two remaining patients had hypometabolism in the cuneus/praecuneus. Correlation analyses showed significant correlations between some test scores (anxiety, depression, health related quality of life) but not fatigue and regional reductions in glucose metabolism. CONCLUSIONS: Although abnormalities in FDG-PET were only detectable in approximately half the CFS patients examined, and no specific pattern for CFS could be identified, PET may provide valuable information in helping to separate CFS patients into subpopulations with and without apparent alterations in the central nervous system.

Adult↗
PubMed2001

A sporadic case of rippling muscle disease caused by a de novo caveolin-3 mutation.

OBJECTIVE: To determine the cause of sporadic rippling muscle disease (RMD) in a 24-year-old patient. BACKGROUND: RMD is a rare myopathy characterized by percussion-induced rapid muscle contractions (PIRC), muscle mounding, and rippling waves. We have recently found that autosomal dominant RMD is caused by mutations in the caveolin-3 gene (CAV3) on chromosome 3p25. Possibly, increased activity of neuronal nitric oxide synthase (nNOS) contributes to the clinical characteristics of increased mechanical muscle hyperexcitability. METHODS: Clinical examination, mutational analysis, and immunohistochemistry of muscle tissue were performed in a patient with sporadic RMD. RESULTS: The authors observed a de novo CAV3 missense mutation Arg26Gln. Immunohistochemistry showed reduced caveolin-3 surface expression in a muscle biopsy. In addition, the authors found normal sarcolemmal nNOS expression and a reduced expression of alpha-dystroglycan in muscle fibers. CONCLUSIONS: These data confirm that RMD is caused by CAV3 mutations. Moreover, there is evidence that CAV3 mutations may also be found in patients without a positive family history of RMD.

Adult↗
PubMed2001

Health-related quality of life in patients with chronic fatigue syndrome: an international study.

OBJECTIVE: Chronic fatigue syndrome (CFS) has been reported worldwide. Our objectives were to determine if patients from different countries have similar profiles of impairments. METHODS: Health-related quality of life (HRQoL) was assessed in 740 CFS patients in the US, 82 in the UK, and 65 in Germany using the eight subscales of the Short-Form General Health Survey (SF-36). To examine the internal structure, factor analyses were performed. RESULTS: Overall, there was a remarkable similarity in HRQoL among all CFS patients, regardless of location. Patients scored two to three standard deviations below normal on six subscales and one standard deviation below normal on the other two subscales. Factor analysis suggested a two-factor model where the same six subscales constitute the first factor and the two others the second factor. CONCLUSION: HRQoL is poor in CFS patients from three countries. This study is a first step towards conducting further comparative cross-cultural and international studies.

Adolescent↗
PubMed1998

[What is certain in pain therapy? The analgesic potency of neuroleptics in the treatment of chronic pain. A metaanalysis].

The wide variety of therapeutic effects make neuroleptics potent drugs in the treatment of pain. Until now there has been no proof of their analgesic potency; in spite of this fact, neuroleptics are used to treat chronic pain states on the assumption that they do have analgesic potency. A metaanalysis was performed and 48 publications reviewed. Thirty-four, the majority of the studies, are case reports, retrospective analyses or non-randomised cohort studies. Most of these reports attest to a positive effect. However, only ten out of fifteen studies with a higher statistical study power describe a possible analgesic effect. None of the studies could differentiate between the effects of analgesia and sedation of the drugs used. The metaanalysis provides no evidence of intrinsic analgesic properties of neuroleptics for their use as adjuvant analgesics.

English Abstract↗
PubMed1998

[Coping with illness in myasthenia gravis in comparison with other chronic neuromuscular diseases].

Seventy-nine patients with chronic neuromuscular diseases were examined by psychodiagnostic tests. The most frequently used coping strategies were "compliance and confidence in the physician", "self encouragement", "to relative by comparison" and "problem-solving". Comparison of the test sample and our total sampling group and the groups divided by diagnosis showed more common features than differences in the coping process. This might be caused by similar general problems in chronic diseases. Less "compliance and confidence in the physician" was the only significant difference between the myasthenic patients and the remaining test group. We supposed less treatment possibilities and/or longer duration of illness (remaining test group) to be responsible for this result. Duration of illness in common seems to have an influence on coping. Patients suffering a longer illness showed reduced values in "self encouragement". Common and specific problems and circumstances of illness seem to be more significant for the coping process than the diagnosis. The patients' mood, which we took as a measure for partial aspects of adaptivity of coping, correlated significantly with the strength of the complaints felt. Classification into adaptive and maladaptive coping forms is not possible.

Adaptation, Psychological↗
PubMed1997

[Indications and value of thymectomy in myasthenia gravis].

The therapeutic impact of thymectomy on the clinical course of myasthenia gravis is still a matter of debate. Issues in this discussion that are clinically relevant are reviewed. While the surgical procedure is accepted for thymomas its performance is controversial in cases with no thymomatous tissue. Outcome studies show a weak correlation between clinical course and thymus histology, but there is some doubt about the maximum age for thymectomy and about the therapeutic regimen following surgery. Retrospective studies show that thymectomy has a beneficial influence on the natural course of myasthenia. This positive effect is enhanced by appropriate immunosuppressive therapy together with anticholinesterase inhibitor substitution. Unfortunately, the different forms of myasthenia do not all respond in the same manner. Studies have shown that thymoma-associated myasthenia is more difficult to control than non-thymoma-associated myasthenic states. In both groups some patients go into remission after thymectomy alone, and the majority of patients with the institution of additional immunosuppression. In clinically mild cases thymectomy should not immediately be followed by immunosuppression. This will help to identify those patients responding with remission to thymectomy alone. Mostly these are young women with a hyperplastic thymus. Overall, thymectomy is beneficial and should be considered in all patients with generalized myasthenia who are still under 60 years of age.

Combined Modality Therapy↗
PubMed1997

Functional properties of motor units in motor neuron diseases and neuropathies.

The relationship between the size of single motor unit (MU) action potentials and their twitch properties was estimated in patients with spinal muscular atrophy (SMA, n = 5) and amyotrophic lateral sclerosis (ALS, n = 10), as well as in patients with peripheral nerve lesions (PNL, n = 9). The data obtained from these groups were compared to normal controls (n = 8). In controls, the single MU twitch force was highly correlated to the corresponding EMG potential size in terms of macro EMG area. An enlargement of MUs, due to collateral sprouting and reflected by increased potential size and twitch force, was found in regenerating PNL and in slowly progressing SMA. Both parameters were highly correlated which indicates a high functional quality of compensating mechanisms. However, in rapidly progressing forms of amyotrophic lateral sclerosis (ALS) this correlation is poor and reflects a disturbance of the contractile system. Contraction times and half relaxation times were not correlated in the different groups.

Action Potentials↗
PubMed1992

Single fiber macro versus concentric trigger macro EMG: a comparison of methods.

The values obtained from two different macro EMG methods were compared, and found to be different. Normally, macro electromyography (EMG) is performed with a modified single fiber (SF) needle using the SF potential as a trigger; a new method recommends a modified concentric needle and triggers on the concentric EMG signal. The concentric macro EMG has a 40% to 50% smaller amplitude and area values than data obtained with a SF macro EMG needle. The different values are the result of variant spatial relationships of the respective needles to the motor unit under study, and may be due to a recruitment-dependent bias resulting from different trigger properties of the two methods. The concentric macro EMG needle can be used to estimate motor unit size, to scan the unit, and to investigate its different concentric EMG signals.

Action Potentials↗
PubMed1992

Myoedema. A clinical and electrophysiological evaluation.

Stationary muscle mounding after muscle percussion without electrical muscle activity is called myoedema. Out of 105 patients with different neurological diseases, 88% had this phenomenon. Muscle conduction velocity and stimulated single fiber EMG disclosed no abnormalities. Myoedema is a normal physiological phenomenon, and its presence does not indicate a neuromuscular disorder.

Brain Ischemia↗
PubMed1992

Persistent unilateral tibialis anterior muscle hypertrophy with complex repetitive discharges and myalgia: report of two unique cases and response to botulinum toxin.

Unilateral enlargement of the tibialis anterior muscle associated with complex repetitive discharges occurred over several months in two patients and was preceded by pain and numbness in the lower leg. Neuroradiologic investigations excluded a compressive radiculopathy, but pharmacologic and neurophysiologic studies suggested a neurogenic basis for the muscle hypertrophy. Botulinum toxin A injection into the hypertrophied muscles led to a decreased muscle volume and cessation of muscle pain.

Adult↗
PubMed1991

[The relative value of electromyography (EMG) in the evaluation of the results of surgical repair of biceps tendon rupture in the arm].

Ten patients treated for rupture of a biceps tendon were re-evaluated 2 years or longer after surgery. Four patients complained of loss of strength and increased fatigue. The concentric EMG examination and the technically more demanding Macro EMG technique showed normal motor unit action potential patterns in the muscle operated on and in the contralateral muscle used as control. The symptom weakness could not be explained by myopathic or neurogenic muscle changes. Concentric EMG had the same diagnostic yield as Macro EMG in this study. Concentric EMG is sufficient to scan for pathological findings within the biceps muscle. If any are present they should initially be interpreted as evidence of a further pathologic condition and not as sequelae of the tendon rupture.

Aged↗
PubMed1991

[Diagnosis, therapy and results of biceps tendon ruptures].

During 1980 and 1988 a total of 29 male patients suffering from ruptures of the biceps tendons were treated operatively. In 21 cases the long tendon was involved, in two the short tendon, and in 6 cases the distal tendon. All ruptures of the long tendon and one of the short tendon had resulted from degeneration without any adequate trauma. Refixation of the long biceps tendon was performed with drill holes along the bicipital sulcus. In ruptures of the short and distal tendon various procedures were applied. Results of operative treatment were better in ruptures of the long biceps tendon than in ruptures of the short tendon. An operation may be successful even some months after injury.

Adult↗
PubMed1990

Effects of intermittent high frequency electrical stimulation on denervated EDL muscle of rabbit.

This study was performed to determine whether electrical stimulation can retard denervation-induced changes. The denervated extensor digitorum longus of the rabbit, a fast-twitch muscle, was stimulated at a rate mimicking its motoneuron firing pattern. The 100-Hz stimulation given intermittently subjected the muscle to a low mean total daily frequency of 1.6 Hz. Four weeks of stimulation resulted in no effect upon the denervated stimulated muscle. This stimulation protocol, therefore, is unable to substitute for the lost neuronal influence of the nerve. The muscle contralateral to the stimulated side showed physiological changes making it unsuitable to serve as a control.

Animals↗