PubMed Health⌕ Search

Biomedical subjects

N J Witt

Publications and source records attributed to N J Witt.

7 recordsLinked to original sources
PubMed1992

Forearm P-31 nuclear magnetic resonance spectroscopy studies in oculopharyngeal muscular dystrophy.

Five siblings with autosomal dominant oculopharyngeal muscular dystrophy (OPMD) underwent P-31 Nuclear Magnetic Resonance Spectroscopy studies of forearm flexor muscles. Mean values of PCr/(PCr+Pi) in the patients were reduced (p = 0.01) and pH elevated (p = 0.02) in resting muscle when compared to controls. During exercise PCr/PCr+Pi) fell quickly to values less than controls (p less than 0.0001) despite submaximal exercise output and developed exercise-induced acidosis which exceeded that of controls (p = 0.05). Acidosis recovered slowly despite relatively normal recovery of PCr/(PCr+Pi) following exercise. Within the patient group, however, one member had normal resting, exercise and recovery values. The studies suggest that OPMD is a more widespread disorder of striated muscle than clinically appreciated. The pattern of findings observed in OPMD differs from those identified in denervation, disuse and mitochondrial myopathy.

Acidosis, Lactic↗
PubMed1991

Peripheral nerve function in sepsis and multiple organ failure.

Forty-three patients who had sepsis and multiple organ failure (critical illness) were studied prospectively to determine the incidence and severity of peripheral nerve function and to correlate such function with a number of variables. Electrophysiologic studies indicated a primary axonal degeneration of motor and sensory fibers in 30 (70 percent). Fifteen (30 percent) had the clinical signs of difficulty in weaning from assisted ventilation, weakness of limb muscles, and reduced or absent deep tendon reflexes. Full recovery from the polyneuropathy occurred among the 23 (53 percent) who survived, except three who had a very severe polyneuropathy. A peripheral nerve function index, computed from electrophysiologic measurements, showed statistically significant (p less than 0.01) negative correlations with the time in the critical care unit, and the serum glucose value; the serum albumin level showed a positive correlation. Multiple regression analyses indicated all three factors accounted for 47 percent (r2 = 0.4678) of all potential variables. In a separate analysis, the nerve function index correlated with the amplitude of the diaphragm compound muscle action potential (p less than 0.01). The results were consistent with the polyneuropathy being due to the same mechanisms that are currently postulated to cause dysfunction in this syndrome of other organ systems (including the neuromuscular respiratory system).

Bacterial Infections↗
PubMed1990

Treatment of refractory Parkinson's disease with adrenal medullary autografts utilizing two-stage surgery.

Treatment of refractory PD with autologous adrenal medullary implants utilizing two-stage surgery warrants further investigation. This transplantation technique is associated with prolonged transplant area BBB disruption which may require a change in medical treatment strategies including the withdrawal of peripheral dopa decarboxylase inhibitors and possible intravenous or intraventricular dopamine therapy. Of 5 patients receiving adrenal medullary transplants, 3 have demonstrated varying degrees of clinical improvement which has persisted for the duration of the study. The positive correlation between clinical outcome and caudate function (i.e., 6-fluorodopa PET scans) suggests a positive influence of the transplantation procedure on the diseased striatum. Whether or not the grafted tissue remains viable for an extended period is currently being investigated utilizing 6-FDG-PET studies. Because of the presence of persistent BBB disruption, we surmise that at least viability of implanted fenestrated adrenal medullary capillaries exists. We conclude that this prolonged leakage is the result of the implanted tissue rather than the cavitation procedure as prolonged BBB disruption was not witnessed in a control group of patients with post-traumatic cerebral contusions or in Parkinson's patients subjected to thalamotomies. Whether two-stage surgery results in increased graft viability, and host neuronal sprouting, leading to prolonged clinical improvement and slowing the progression of PD awaits continued longitudinal (greater than 24 months) studies.

Adrenal Medulla↗
PubMed1988

Neuromuscular disorders and thymoma.

We describe a patient who had asymmetrical atrophy of limb muscles and myasthenic weakness of neck, facial, and bulbar muscles. Electrophysiological tests indicated myasthenia gravis of facial muscles and changes consistent with an asymmetrical motor neuropathy as a cause of the muscle atrophy. Both conditions occurred as complications of a locally invasive thymoma, and both failed to improve after surgery and radiation but substantially improved with subsequent treatment by corticosteroids, azathioprine, and plasmapheresis. Review of the literature disclosed that several neuromuscular conditions may be associated with thymoma, the commonest being myasthenia gravis. Muscle atrophy may occur in 10% of patients who have myasthenia gravis, whether associated with or without thymoma. Its mechanism is debated, and further studies are needed, but observations in our patient suggest the atrophy is due to a motor neuropathy. Primary treatment of the thymoma by surgery, irradiation if the tumor is invasive, and immunosuppressive therapy for neuromuscular complications offers a relatively good prognosis for this group of patients.

Action Potentials↗
PubMed1986

Critically ill polyneuropathy: electrophysiological studies and differentiation from Guillain-Barré syndrome.

A polyneuropathy of varying severity has been observed in association with sepsis and critical illness in 15 patients. Since clinical evaluation is often difficult, electrophysiological studies provided definitive evidence for polyneuropathy. These revealed reductions in the amplitudes of compound muscle and sensory nerve action potentials, the most marked abnormality. Near-nerve recordings confirmed such reductions for sensory fibres. Needle electromyography revealed signs of denervation of limb muscles. Phrenic nerve conduction and needle electromyographic studies of chest wall muscles suggested that the polyneuropathy partially explained difficulties in weaning patients from the ventilator, an early clinical sign. No defect in neuromuscular transmission was demonstrated, despite the use of aminoglycoside antibiotics in some patients. In those who survived the critical illness, clinical and electrophysiological improvement occurred. The 15 critically ill polyneuropathy patients were compared with 16 Guillain-Barré syndrome patients observed during the same period. The analysis showed that the two polyneuropathies are likely to be separate entities that can be distinguished in most instances by the predisposing illness, electrophysiological features and cerebrospinal fluid results.

Aged↗
PubMed1984

Are right-hemisphere lesions really larger? Lesion size and laterality in meningioma patients.

Patients with pathologically confirmed diagnoses of meningioma were examined to investigate the hypothesis that left-hemisphere lesions are smaller or declared earlier than right-hemisphere lesions. 77 patients were examined with regard to age at presentation and nature of symptoms. In addition CAT scan films of 47 patients were obtained for measurement of lesion size. There were no differences between right and left lesion groups with regard to size of lesion or age at presentation. Subgroups of patients with lesions in frontal association areas also did not differ. Some relationships were discovered between lesion location and nature of symptoms.

Brain↗