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Biomedical subjects

Y L Yu

Publications and source records attributed to Y L Yu.

At least 109 records · Page 6Linked to original sources
PubMed1986

Computer-assisted myelography in cervical spondylotic myelopathy and radiculopathy. Clinical correlations and pathogenetic mechanisms.

A total of 53 patients with cervical spondylotic myelopathy and/or radiculopathy were studied with computer-assisted myelography following metrizamide myelography. Cervical cord deformities resulting from spondylotic protrusions were classified into four groups. The A shape (anterior central concavity) is the commonest and is often associated clinically with bilateral anterolateral and posterior column deficits. In the B shape (lateral deformity on one side), unilateral anterolateral column and root signs, usually mild, predominate. The symptomatology of the C shape (lateral deformity on both sides) and the D shape (flattened anterior surface) is bilateral, although not often symmetrical, and includes anterolateral and posterior column disturbances and root signs. Radiculopathy may, however, occur in the absence of cord deformity if the spondylotic lesion is close to or inside the intervertebral foramen. As there is some relationship between cord shapes and symptomatology, the decision as to whether a particular deformity is responsible for the clinical presentation may be made with more confidence. Moreover, the degree of cord deformity correlates well with the severity of symptomatology. Those with mild deformity had relatively few or mild cord signs, whereas in those with severe deformity cord signs were numerous and severe. Certain observations on cord deformity in vivo support the view that compression is an important pathogenetic mechanism in cervical spondylotic myelopathy. Most patients had anterior cord compression and the anterolateral signs were more frequent and marked. Severity of cord signs is associated with the degree of compression. Removal of the compression is followed by re-expansion of the cord and clinical improvement. In a small number of cases where cord compression by osteophytic protrusion was mild, and where clinical improvement followed the removal of the protrusion, the theory of cord traction and friction appears to apply. The contribution of other mechanical factors and of ischaemia to cord damage is also discussed.

Adult↗
PubMed1986

Spinal cord compression in multiple myeloma: who gets it?

Of 97 Chinese patients with multiple myeloma seen over a 12-year period, 23.7% were found to have cauda equina or spinal cord compression (SCC). Predictive features for SCC include paraprotein type, hemoglobin level, and the extent of bone lesion at initial hematological diagnosis. A discriminant function derived from this analysis can be used to predict the likelihood of SCC with 79% accuracy. It is postulated that when the cortex is more involved than the medulla in a vertebra, it will predispose to SCC while hemopoiesis is relatively preserved. Our patients presented late with advanced neurological deficit so that treatment was unsatisfactory. It is emphasised that early recognition of back pain and neurological symptoms is essential, as any delay would jeopardize the chance of neurological recovery.

Adult↗
PubMed1986

The use of lisuride in severe Parkinson's disease.

Four patients with severe Parkinson's disease were given a trial of lisuride. Two patients responded well, but the other 2 developed psychiatric complications which seemed to be a major limiting factor in the use of the drug. Otherwise, lisuride could be useful in difficult Parkinsonian patients who have a diminished response to levodopa.

Adult↗
PubMed1986

Cryptic miliary tuberculosis.

Fifteen patients with cryptic miliary tuberculosis seen over a six-year period in a large teaching hospital were reviewed. This form of tuberculosis tended to be difficult to diagnose and was most common in older people and those with underlying diseases such as malignancy or blood dyscrasias. Bacteriological investigation was of the little help in diagnosis while bone marrow and liver biopsies were more useful. The diagnosis was made during life in only seven (47 per cent) of the 15 cases, and the overall mortality was 80 per cent. Tuberculosis should be considered in all cases of pyrexia of unknown origin, and investigations performed to establish or exclude the diagnosis. A prompt and adequate therapeutic trial with antituberculous treatment even in the absence of definite evidence of tuberculosis can be life-saving.

Adolescent↗
PubMed1985

Morphology and measurements of the cervical spinal cord in computer-assisted myelography.

Thirty-six control subjects had computer assisted myelography (CAM) using the EMI CT 5005 scanner. The normal cervical cord is elliptical, more circular at the upper and lower ends and flatter in the mid-segments. Asymptomatic cord deformities, usually mild, were present in nine subjects (25%). Four measurements, namely, sagittal diameter (APD), transverse diameter (TD), area (a) and circumference (c) were made and two more parameters calculated i.e. APD/TD ratio and circularity (= 4 pi a/c2). These control values form the basis of qualitative and quantitative assessment of cord deformity. When cord measurements are to be used, control values should be obtained for each scanner and procedures should be standardized.

Adult↗
PubMed1985

Somatosensory evoked potentials in cervical spondylosis. Correlation of median, ulnar and posterior tibial nerve responses with clinical and radiological findings.

Somatosensory evoked potentials (SEPs) following median, ulnar and tibial nerve stimulation were recorded from sites over the shoulders, neck and scalp in 34 patients with cervical spondylosis. Twenty control subjects were matched for sex and age. Detailed clinical and radiological data were assembled, with particular attention to the sensory modalities impaired and the locus and severity of cord compression. The patients were divided clinically into 4 groups: combined myelopathy and radiculopathy (6 cases), myelopathy alone (15), radiculopathy (6) and neck pain (7). Four cases are described in detail. SEP abnormalities were strongly correlated with clinical myelopathy, but not with radiculopathy. Median and ulnar nerve responses were less often affected than tibial, even with myelopathy above C6 level. Tibial nerve SEP abnormalities were strongly correlated with posterior column signs on the same side of the body, but not with anterolateral column sensory signs. In myelopathy cases, the SEP examination appeared to be more sensitive to sensory pathway involvement than clinical sensory testing. SEP abnormalities were infrequent in cases of radiculopathy and neck pain, bearing no relation to the clinical locus of root lesions. Abnormal SEPs consistent with subclinical posterior column involvement, however, were recorded in 1 patient with radiculopathy and 2 with neck pain. Follow-up recordings made postoperatively in 7 myelopathy cases reflected the clinical course (improvement, deterioration or no change) in 4, but failed to reflect improvement in 3. The correlation of SEP findings with radiological data was generally poor. SEP abnormalities were detected in 6 out of 8 patients with clinical myelopathy but no radiological evidence of posterior cord compression, suggesting that impairment of the blood supply may be an important factor contributing to cord damage. An application for SEPs in the clinical management of cervical spondylosis may lie in the detection of posterior column involvement and the differential diagnosis from disorders such as multiple sclerosis and amyotrophic lateral sclerosis.

Adult↗
PubMed1985

Small cerebellar strokes may mimic labyrinthine lesions.

Thirty nine cases of cerebellar infarct and haemorrhage were seen over a period of 3 years. Of these, 69% had no impairment of consciousness. Six cases had nystagmus and gait ataxia as their only abnormal signs. Small cerebellar strokes may present with only vertigo, unsteady gait, and unidirectional nystagmus, thus mimicking labyrinthine lesions. Care in managing vertigo attacks in patients with risk factors for cerebrovascular disease appears to be warranted.

Adult↗
PubMed1984

Is there an increased risk of early side effects of metrizamide in post-myelogram computed tomography?

The safety of post-myelogram computed tomography (PMCT) as an additional diagnostic procedure to metrizamide myelography was evaluated. One hundred and four consecutive patients with suspected cervical cord lesions were studied prospectively; 50 had both myelography and PMCT, and the 54 acting as controls had only myelography. PMCT did not increase the incidence, severity or duration of common side effects and the majority of patients accepted this additional procedure. It is concluded that as long as care is taken to avoid the occurrence of excessive contrast in the intracranial subarachnoid space, PMCT is a safe procedure.

Adult↗
PubMed1984

A comparison of concentric needle electromyography, quantitative EMG and single fibre EMG in the diagnosis of neuromuscular diseases.

Conventional concentric needle electromyography, quantitative electromyography using automatic analysis (Quant-EMG) and single fibre electromyography (SFEMG) were compared in the right biceps muscle of 10 patients with anterior horn cell disease and 20 patients with primary muscle disease. Abnormalities were demonstrable by all 3 techniques in the majority of cases irrespective of whether the biceps was weak. SFEMG was found to be more sensitive than Quant-EMG in neurogenic cases and it also provided an indication of disease activity. In cases of myopathy Quant-EMG was of more diagnostic help and was easier to perform than SFEMG. Large amplitude potentials found in some cases of myopathy were associated with increase in the mean amplitude on Quant-EMG and these probably emanate from hypertrophied muscle fibres.

Adult↗
PubMed1984

Evidence of vascular disease from CT scanning in late onset epilepsy.

The CT scans of 74 patients presenting with late-onset epilepsy not due to cerebral tumour were compared with those of an age and sex-matched control group for evidence of cerebral vascular disease. Changes in the scan indicative of cerebral atrophy (enlarged ventricles and cortical sulci) were seen in similar numbers in both patients and controls. However, the scans revealed a highly significant excess of ischaemic lesions in the epileptic patients, in the form of discrete areas of infarction and low attenuation of the periventricular white matter. These changes, which were only seen in two of the controls, were present in 13 of the epileptic patients. The median age at the onset of epilepsy in the 13 patients with ischaemic lesions was 62 years, and they showed an increased incidence of systemic vascular disease and of abnormal neurological signs. In six of the 13 cases, however, clinical examination was normal and CT scanning provided the only evidence of underlying vascular disease.

Adult↗
PubMed1983

Direct determination of phenylalanine in serum extracts of phenylketonuria patients by reversed-phase high-performance liquid chromatography.

A method for direct determination of phenylalanine (Phe) in serum extract by reversed-phase high-performance liquid chromatography with an octadecylsilane column has been devised. Phe is monitored at 220 nm with a UV detector. The mobile phase is a mixture of methanol and water (10:90) with added phosphoric acid and potassium dihydrogen phosphate and has a pH value of 4.3. The minimum detectable amount is 6 ng. The average contents of Phe found for healthy adults and children are 12 and 15 micrograms/ml respectively. Phe contents of sera of three phenylketonuria children are about 10 to 15 times higher than these values.

Adult↗
PubMed1982

The clinical picture of ectasia of the intracerebral arteries.

Thirty-one patients with ectasia of intracranial arteries were studied. The carotid system was more frequently involved than the vertebrobasilar. The condition is relatively rare and usually occurs with other vascular disease. Ectasia presents with a variety of neurological symptoms, amongst which visual disorders are common. The overall mortality was 52%, but the prognosis was appreciably worse for the vertebrobasilar group, probably because of a higher incidence of compression of surrounding neural structures. Defects in the internal elastic lamina, with or without associated atheroma, are often found in the affected arteries.

Adult↗
PubMedDate not supplied

Chronic effects of phenytoin on brain-stem auditory evoked potentials in man.

The effects of phenytoin (PHT) on brain-stem auditory evoked potentials (BAEPs) were studied in 65 epileptic patients who received long-term PHT monotherapy at therapeutic and supra-therapeutic levels with no clinical evidence of brain-stem toxicity. Abnormal BAEPs were found in 7.5% and 33.3% of patients with therapeutic and supra-therapeutic PHT levels respectively. Serum PHT levels had a trend towards a positive relationship with the I-V interpeak latency (IPL), and a significant negative relationship with the amplitudes of waves I and V. At supra-therapeutic levels, both I-V and I-III IPLs were significantly prolonged while at therapeutic levels only I-III IPLs were prolonged. The absolute latency of wave I was prolonged in both the therapeutic and the supra-therapeutic groups. These results suggest that PHT acts both peripherally on either the auditory nerve or the cochlea, and centrally on brain-stem conduction.

Adolescent↗