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Biomedical subjects

S Bajada

Publications and source records attributed to S Bajada.

17 recordsLinked to original sources
PubMed1986

Peripheral sympathetic conduction velocity calculated from surface potentials.

A simple, non-invasive and well tolerated technique is described for measuring autonomic nerve conduction velocity (ANCV) using proximal and distal peripheral autonomic surface potential (PASP) recordings. ANCV were obtained in 90% of subjects, and are comparable to values measured by intraneural recording. This technique may have applications in the assessment of autonomic neuropathies and can be readily performed in a standard EMG laboratory.

Adult↗
PubMed1985

Peripheral autonomic surface potential. A quantitative technique for recording sympathetic conduction in man.

Using EMG equipment with time locked recording and standard averaging facilities we were able to record a previously poorly defined skin potential. The potential, termed by us the peripheral autonomic surface potential (PASP), was recorded from the palmar surface of the hand and the plantar surface of the foot in 30 normal subjects. The PASP usually consisted of a biphasic potential with an initial negative and a later positive peak. It was elicited by randomly timed electrical stimuli over the median nerve at the wrist. The mean palmar PASP latency was 1.52 +/- 0.13 s and the mean plantar PASP latency was 2.07 +/- 0.16 s. The mean palmar and plantar PASP amplitudes were 479 +/- 105 microV and 101 +/- 40 microV, respectively. A mean sympathetic conduction velocity was calculated to be 1.28 +/- 0.18 m/s. In 5 normal subjects a similar technique was used to record a PASP from the volar surface of the left middle finger. Iontophoresis of atropine into the skin under the recording site abolished the PASP in all subjects. Palmar and plantar PASPs were recorded in 10 diabetic patients. The amplitudes (palmar 179 +/- 158 microV, plantar 17 +/- 16 microV) were significantly reduced compared to normals (P less than 0.001). Five patients with unilateral lumbar or cervical sympathectomy were studied. The PASP was absent or markedly reduced on the side of the sympathectomy in all patients.

Adult↗
PubMed1985

Peripheral autonomic surface potential: a quantitative technique for recording autonomic neural function in man.

Using EMG equipment with time-locked recording and standard averaging facilities we were able to record a previously poorly studied skin potential. The potential, termed by us by the peripheral autonomic surface potential (PASP), was recorded from the palmar surface of the hand and the plantar surface of the foot in 20 normal subjects. The PASP consisted of a biphasic potential with an initial negative and a later positive peak. The mean palmar PASP latency was 1.51 +/- 0.19 seconds and the mean plantar PASP latency was 2.09 +/- 0.24 seconds. The mean palmar and plantar PASP amplitudes were 485 +/- 100 microV and 102 +/- 45 microV respectively. A mean central sympathetic conduction velocity was calculated at 1.2 +/- 0.21 m/s. In two patients with unilateral lumbar sympathectomy the ipsilateral plantar PASP was absent in one and of considerably reduced amplitude in the other. Both palmar and plantar PASPs were absent or of reduced amplitude in five patients with diabetes mellitus. The study indicates that the PASP may prove a useful quantitative test of central and peripheral autonomic function.

Adult↗
PubMed1981

Nerve conduction velocity in experimental diabetes in the rat and rabbit.

Tibial motor nerve conduction velocity was measured in rats, before and two months after the induction of diabetes with streptozotocin. A second group of diabetic animals was also administered 1% dietary myoinositol supplements. An analysis of variance was performed on these data. Myoinositol supplements had no effect whatsoever. The period of diabetes had a statistically significant and quantitatively marginal effect (a decrease of 2.2 m s-1) on conduction velocity. This is considerably less than in previous reports. The reasons for this are discussed. Tibial motor nerve conduction velocity was also measured in a group of alloxan-diabetic rabbits two months after the induction of diabetes and in an age-matched control group. Conduction velocity was again slightly but significantly less in the diabetic animals.

Animals↗
PubMed1981

Transcutaneous sympathetic stimulation: effects of autonomic nervous function.

In recent years the use of transcutaneous electrical nerve stimulation (TENS) for the treatment of painful disorders has been widely adopted. Minor side effects such as skin irritation are recognised but with appropriate safeguards the technique is considered free from permanent sequelae. This study examines the effects of TENS on hand skin temperature in 6 normal volunteers and 3 patients with alcoholic peripheral neuropathy. Changes of skin temperature were registered using thermocouples and a thermovision camera. Digital artery pulsation was recorded using the Doppler ultrasound technique. Stimulation at 5 to 10 per second of the ulnar nerve at the elbow and digital nerves in the fingers was maintained for 1 to 4 minutes. Profound cooling of the skin and decrease in arterial pulsation was observed and usually persisted for several minutes after cessation of stimulation. Digital arterial changes were not seen in the 3 patients with neuropathy. The possible physiological basis of the observations is discussed and the implications for TENS therapy considered.

Alcoholism↗
PubMed1980

Amyloid neuropathy and tremor in Waldenström's macroglobulinemia.

We report a case of Waldenström's macroglobulinemia with amyloid neuropathy and a parkinsonian syndrome. We describe the light and electron microscopic findings in a sural nerve biopsy specimen and discuss the possible pathogenic mechanisms in the production of the neuropathy. In contrast to a number of previous cases of neuropathy associated with Waldenström's macroglobulinemia, evidence of immunoglobulin deposition on nerve fibers was not found using immunofluorescent techniques.

Amyloidosis↗
PubMed1980

[Automatic analysis of the electromyogram: technique and results in healthy and ill subjects].

The EMG signal was recorded from the brachial biceps in 12 different needle positions, in control subjects and patients, all the subjects exerting a standard effort. The signal was automatically analysed, off-line, and 18 parameters were computed from the signal waves. These parameters described the electrical activity of the muscle. The comparison between results from control subjects and patients showed significant differences for 13 parameters. Eight of them allowed one to separate neurogenic and myogenic patients. For each parameter, the observed variations from the normal exhibited opposite values for neurogenic and myogenic subjects. Some neurogenic patients with apparently normal biceps had a pathological quantitative analysis. The method could thus be used to reveal early disturbances.

Adolescent↗
PubMed1980

Axoplasmic transport in vagal afferent fibres in normal and alloxan-diabetic rabbits.

Fast and slow components of anterograde axoplasmic transport have been studied in the sensory fibres of the vagus nerve of alloxan-diabetic rabbits and age-matched controls by incorporation of tritiated leucine into nodose ganglion cells. The diabetic rabbits were maintained for 2 months with blood glucose levels in the range 20--40 mmol/l. They showed growth retardation and one third developed cataracts. No alteration of either fast or slow axoplasmic transport was detected in the diabetic animals. These results are discussed in the light of the present understanding of the role of axoplasmic transport, of the findings in other axoplasmic transport studies, and of other data available on the pathogenesis of human and experimental diabetic neuropathy.

Animals↗
PubMed1980

Age changes in the tibial and plantar nerves of the rat.

Observations have been made on the changes in the myelinated fibres of the rat tibial and plantar nerves between 2 and 24 months of age. There is an initial rapid increase in fibre diameter followed by a later more gradual increase, which ceases after approximately 9 months of age in the tibial nerve but which continues for longer in the medial plantar nerve. The fibre size distribution remains substantially unimodal throughout. In both nerves maximal and average fibre diameter become reduced by 24 months. Total fibre number shows considerable variability between animals, but no definite systematic alteration with age is detectable. Teased fibre preparations demonstrate a low level of abnormality in the tibial nerve until after 18 months of age, but by 24 months approximately 30% of fibres display abnormalities. Although both paranodal and segmental demyelination and remyelination, and axonal degeneration and regeneration occur, the latter type of change predominates. By contrast, in the lateral plantar nerve paranodal and segmental demyelination become detectable to a significant extent from 6 months of age. Axonal degeneration and regeneration also become evident after 15 months, and by 24 months of age 55% of fibres show abnormalities. The possible explanation of these changes is discussed, as is their relevance to the frequent use of the tibial nerve for studies on experimental neuropathies.

Aging↗
PubMed1979

Dihydroergotamine therapy in symptomatic postural hypotension.

The clinical response to therapy with dihydroergotamine (DHE) has been evaluated in one patient with idiopathic orthostatic hypotension. The results of tests performed on the autonomic nervous system are recorded, and the evidence for a central defect in postural blood pressure control is presented. Tilt table testing over a two-month period confirmed the beneficial effect of the medication in preventing profound falls of blood pressure. The dose required (20 mg/day) was higher than previously reported.

Aged↗
PubMed1977

Resting tremor in alcoholic brain disease.

Two patients with signs of alcoholic brain disease of the Wernicke-Korsakoff type were found to have an unusual movement disorder manifested basically as a resting tremor. Electrographic recording showed that the tremor wave comprised multiple elements, though the rate of the basic tremor was stable. Though the tremor was qualitatively similar to documented rubral tremor, a mesencephalic lesion could be defined in only 1 patient.

Alcohol Amnestic Disorder↗
PubMed1976

Cerebellitis in glandular fever.

Cerebellitis as an unusual manifestation of infectious mononucleosis is reported for the first time in Australia. Complete recovery occurred, as has been the rule in previously described cases. The difficulty that may be encountered in early diagnosis is discussed, and screening for infectious mononucleosis is suggested for elusive neurological illnesses. The possible significance of cerebrospinal fluid antibodies is considered.

Adolescent↗
PubMedDate not supplied

[Digital computer analysis of the electromyogram: preliminary report (author's transl)].

This is a preliminary report of a method of digital computer analysis of the electromyogram recorded from twenty sites in biceps brachial during fixed voluntary effort. The method allows several EMG parameters to be studied. The results in a group of normal subjects have been compared with those in patients with neuromuscular disease. Three parameters have proved of value in differentiating normal subjects from those with neurogenic disease.

Adult↗