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Biomedical subjects

N S Chu

Publications and source records attributed to N S Chu.

At least 37 records · Page 2Linked to original sources
PubMed1998

X-linked recessive bulbospinal neuronopathy: clinical and molecular studies in a Taiwanese family.

We describe clinical, biochemical, and molecular studies on a Taiwanese family with X-linked recessive bulbospinal neuronopathy. There were three probands and five female carriers among the 23 members examined. The clinical manifestations included progressive muscle weakness, diffuse fasciculation, postural tremor, muscle cramps, dysarthria, dysphagia, diabetes, and gynecomastia. Phenotypic expression varied among the affected subjects. Two carriers also had postural tremor and perioral fasciculation. Endocrine tests were normal except for a mild increase in serum testosterone and/or growth hormone in one patient and one carrier. Type IV hyperlipoproteinemia was observed in two patients, one carrier, and one healthy offspring. Molecular genetic studies confirmed elongation of the CAG triplet repeat in exon 1 of the gene for the androgen receptor. Sequence analysis showed that there were 42 to 43 CAG repeats in the three probands and 42 to 45 in the five carriers. The mutant allele had a tendency to increase by one or two repeats from one generation to the next. The length of CAG repeats at which the mutant allele became unstable was shorter in our family than in previous reports. The normal allele was also unstable and had a tendency to shrink by one of five repeats during transmission. These findings suggest that the number of CAG triplet repeats is variable in both the mutant and normal alleles.

Adolescent↗
PubMed1997

Childhood-onset autosomal-dominant limb-girdle muscular dystrophy with cardiac conduction block.

We report childhood-onset autosomal-dominant limb-girdle muscular dystrophy (LGMD) in a Chinese family with complete atrioventricular conduction block in the adult members. Six patients, including 5 men and 1 woman with an age of onset from 3 to 7 years, were affected. The grandfather had exercise intolerance since childhood and complete heart block with pace-maker placement at age 52. Three siblings had proximal muscle weakness and/or wasting since age 5 and heart block in their 40s. Two grandsons at the ages 7 and 3 showed exercise intolerance, and proximal muscle weakness and wasting. Sinus bradycardia was present in the elder grandson. Muscle enzymes were elevated in 3, particularly in childhood. Muscle biopsies from the proband showed myopathic changes with fatty degeneration, whorled fibers, and rimmed vacuoles. In adult patients, muscle magnetic resonance imaging scans disclosed atrophic changes and fatty degeneration in the gluteal, quadriceps, adductors, hamstrings, gastrocnemius, and soleus muscles, while in child probands the early atrophic changes were seen in the gluteal and hamstrings muscles. We conclude that this distinct family is characterized by childhood-onset autosomal-dominant LGMD with heart block and that prevention of sudden death in these patients is important.

Adolescent↗
PubMed1997

Patterns of sympathetic skin response in palmar hyperhidrosis.

Sympathetic skin responses (SSRs) were studied in 44 patients with palmar hyperhidrosis. The mean age was 19 +/- 4 years and the mean age of onset 9.1 +/- 3.6 years. Palmar SSRs were evoked by median nerve stimulation and by magnetic stimulation of the neck. Four types of SSR were identified: normal response, small-amplitude response, multiphasic response and absent response. Four palmar conditions were also identified: warm-wet in 26 patients, warm-dry in seven, cold-wet in seven, and cold-dry in four. Normal SSRs were present in about 25% of patients and absent SSRs in another 25%. The other two types of SSR were evenly distributed among patients, except those with cold-dry palms, who only had absent responses. There was no apparent difference between centrally and peripherally activated SSRs. It is concluded that skin temperature and moisture of the palms play an important role in producing different types of SSR in palmar hyperhidrosis.

Adolescent↗
PubMed1997

Autonomic involvement in Wilson's disease: a study of sympathetic skin response and RR interval variation.

Autonomic nervous system involvement in Wilson's disease (WD) was studied in 25 patients by sympathetic skin response (SSR) and RR interval variation (RRIV). The control group consisted of age-matched healthy subjects. Palmar SSRs were obtained by central activation from median nerve stimulation and by activation of sympathetic trunk from magnetic stimulation of the neck. Electric SSRs were prolonged in 11 patients and absent in 2; magnetic SSRs were delayed in 4 and absent in 1; and the sympathetic central conduction time was prolonged in 3. The mean latencies and mean central conduction of the SSRs were all significantly prolonged in WD when compared to the control group. On the other hand, parasympathetic function was abnormal in 3 patients only during forced deep breathing, and as a group only mean D% was significantly reduced. The present findings suggest that autonomic dysfunction may occur in WD, and that sympathetic function is predominantly affected, mainly due to central involvement.

Adolescent↗
PubMed1997

Evoked potentials in liver diseases.

Evoked potentials are objective and quantitative methods capable of evaluating functions of both peripheral and central nervous systems (PNS and CNS). During the past 8 years, we have been using somatosensory, brainstem auditory, and pattern-reversal visual evoked potentials (SEP, BAEP, VEP) to study hepatic encephalopathy (HE) as well as functional status of the PNS and CNS in various liver diseases including viral hepatitis B, alcoholic liver disease and Wilson's disease (WD). In HE irrespective of its etiologies, there is a sequential prolongation and eventual disappearance of cortical components of the median nerve evoked SEP while there is no change in BAEP, suggesting that HE is primarily due to a disturbance in cerebral cortical function and that median SEP may be used for early detection of HE and for monitoring its clinical course. In addition, absence of the N20-P25 component, or presence of only the N20 component of the wave complex in fulminant hepatic failure is associated with high mortality, whereas presence of late cortical components in HE is usually associated with reversibility of clinical course. Central conduction time (CCT) of the BAEP is prolonged in patients with WD, alcoholic liver disease and liver cirrhosis due to hepatitis B. Furthermore, BAEP abnormality is most severe in WD, followed by alcoholic liver disease, and finally hepatitis B. Peripheral nerve conduction as determined by the N9 latency of SEP is slowed in alcoholic liver disease and liver cirrhosis of chronic hepatitis B, but normal in WD. Our studies, therefore, suggest that evoked potentials may be useful in the evaluation of both CNS and PNS functions in various liver diseases and also in the diagnosis and monitoring of HE.

Evoked Potentials, Auditory, Brain Stem↗
PubMed1997

Peripheral neuropathy in mitochondrial encephalomyopathies.

Seven patients with mitochondrial encephalomyopathies were studied for peripheral neuropathy by clinical, electrophysiological and pathological examinations. The clinical manifestation of neuropathy varied from asymptomatic to mild and moderate sensorimotor symptoms with painful paresthesia. Five patients (2 with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes, and 3 with myoclonic epilepsy and ragged-red fibers, MERRF) had clinical symptoms and signs of polyneuropathy associated mainly with decreased amplitudes of the compound muscle or nerve action potentials in an electrophysiological study indicating axonal degeneration. Sural nerve biopsy from 1 MERRF patient, also confirmed an axonal degeneration with reduction of large myelinated fibers. Mitochondrial DNA analysis of the sural nerve from this patient showed a point mutation from A to G transition at the nucleotide position 8344 with 80% mtDNA mutation. The results of this study suggest that peripheral neuropathy is not uncommon in mitochondrial encephalomyopathies and is predominantly due to axonal degeneration.

Adolescent↗
PubMed1997

Coenzyme Q10 treatment in mitochondrial encephalomyopathies. Short-term double-blind, crossover study.

We report a short-term double-blind, crossover study of CoQ10 in 8 patients with mitochondrial encephalomyopathies. Four patients had myoclonus epilepsy with ragged-red fibers syndrome, 3 had mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes syndrome, and 1 had chronic progressive external ophthalmoplegia with myopathy. A trend of effectiveness of CoQ10 in several parameters was noted. Fatigability of daily activities was alleviated. The endurance to muscle exercise was augmented. Global muscle strength scored by Medical Research Council scale was increased. The extent of elevation in serum lactate and pyruvate levels after exercise was decreased. However, only the global MRC index score had a statistical significance (p < 0.05). There were no side effects during therapy. The serum CoQ10 levels were significantly lower in patients than in normal controls before CoQ10 treatment and increased significantly after treatment.

Activities of Daily Living↗
PubMed1997

Presynaptic and postsynaptic striatal dopaminergic function in patients with manganese intoxication: a positron emission tomography study.

We performed PET on four patients with chronic industrial Mn intoxication; presynaptic and postsynaptic dopaminergic function were measured with [18F]6-fluoro-L-dopa (6FD) and [11C]raclopride (RAC). All patients had a rigid-akinetic syndrome; they had no sustained benefit from L-dopa. Influx constants (Ki) of 6FD were normal in the caudate and putamen. RAC binding was mildly reduced in the caudate and normal in the putamen. We conclude that nigrostriatal dopaminergic dysfunction is not responsible for the parkinsonism caused by chronic Mn intoxication. The pathology is likely to be downstream of the dopaminergic projection.

Adult↗
PubMed1997

Neuroimaging in intractable complex partial seizures.

We retrospectively analyzed 19 patients with intractable complex partial seizures who underwent temporal lobectomy and compared the usefulness of various imaging techniques in diagnosis and localization. Pathologic findings consistent with mesial temporal sclerosis were found in 12 patients arteriovenous malformations in four, tumors in three, and coexistence of a tumor and mesial temporal sclerosis in one. Electroencephalography and single photon emission computed tomography detected lateralized functional abnormality in two patients when computed tomography (CT) and magnetic resonance imaging (MRI) showed equivocal results. Both CT and MRI showed all arteriovenous malformations and tumors. CT detected only four cases of mesial temporal sclerosis, while MRI showed nine cases. Detection, delineation and diagnosis of lesions responsible for complex partial seizures are essential for good surgical results. Thus, the importance of image studies, especially MRI, should be emphasized in patients with complex partial seizures.

Adolescent↗
PubMed1997

Occupational neurotoxic diseases in Taiwan: a review of the outbreaks and clinical features.

In the past 20 years, several outbreaks of neurotoxic disease due to occupational exposure have occurred in Taiwan. The most notorious outbreaks were 'Yu-cheng' due to contamination of polychlorinated biphenyls in cooking oil, lead poisoning in battery manufacturers and workers in a ship-scrapping yard, tile factory and battery recycling plants, and n-Hexane intoxication in press-proffers and ball-manufacturers. In addition, there were manganese intoxication in ferromanganese smelters, mercury intoxication in lamp-socket workers, carbon disulfide intoxication in viscose rayon workers and hydrogen sulfide intoxication in chemical synthetic plants. Although the incidence of occupational neurotoxic diseases has increased, the real incidence is probably still underestimated. The reasons for the underestimation include: 1) the education for workers in industrial hygiene is inadequate; 2) high risk workers are not screened well; 3) physicians are not well trained in early diagnosis of occupational diseases; 4) material safety data information is not readily available in the factories; and 5) the threshold limit values for toxic substances are relatively high in Taiwan, compared with other developed countries.

Carbon Disulfide↗
PubMed1997

Proton magnetic resonance spectroscopy in patients with complex partial seizures.

We prospectively studied eight patients with complex partial seizures, using single-voxel proton magnetic resonance spectroscopy (MRS). Control data from 12 healthy volunteers were obtained with the same MRS protocol. The ratios between the peak areas of N-acetylaspartate, creatine and phosphocreatine (Cr), and choline-containing compounds (Cho) were analyzed. The results showed statistically significant lower N-acetylaspartate:Cr, N-acetylaspartate:Cho, and N-acetylaspartate: Cho + Cr ratios, and a higher Cho:Cr ratio in the mesial temporal lobes of the patient group than in healthy controls. Because N-acetylaspartate is located in the neurons and Cho and Cr in the glial cells, these observations represent the underlying neuronal loss and reactive astrocytosis in the epileptogenic foci. MRS can detect abnormal metabolic changes in most complex partial seizure patients with normal electroencephalography and magnetic resonance images. MRS can also identify bitemporal abnormalities which are a common feature in patients with complex partial seizures. Proton MRS could not confirm the specific location of seizure foci. Further investigation with quantitative spectral analysis and correlation with surgical outcome is needed to improve the contribution of MRS to the diagnosis and localization of seizure foci.

Adult↗
PubMed1996

Current perception thresholds in toe-to-digit transplantation and digit-to-digit replantation.

Recovery of digital nerve function in toe-to-digit transplantation and digit-to-digit replantation was evaluated by transcutaneous constant current sine wave stimulation at 5-, 250-, and 2000-Hz frequencies to determine the current perception thresholds (CPT). For toe transplantation and digit replantation, the mean interval between injury and surgery was 9 months and 7 h, respectively, while the mean interval between surgery and CPT study was 52 months and 20 months, respectively. Control CPTs evoked by three frequency stimuli were obtained from contralateral corresponding normal finger and normal toe. Normal finger had significantly lower 250- and 2000-Hz CPTs than normal toe, but the 5-Hz CPT was not different between them. Replanted digit achieved nearly complete recovery of these three frequency CPTs when compared to normal finger. In toe transplantation, 2000-Hz CPT was comparable to normal finger, while 5- and 250-Hz CPTs were comparable to normal toe. The present findings suggest that the transplanted toe was intermediate between normal finger and normal toe, but more like normal toe than normal finger with regard to detection thresholds of the current-evoked sensation.

Adult↗
PubMed1996

Recovery of sympathetic skin responses after digit-to-digit replantation and toe-to-digit transplantation in humans.

Sympathetic skin response was utilized to study recovery of sudomotor function in 8 patients who had digit-to-digit replantation and 9 patients who had toe-to-digit transplantation. Sympathetic skin responses evoked by median nerve stimulation or magnetic stimulation of the neck were recorded from the tip of the replanted digits or transplanted toes. The contralateral normal fingers served as controls. The mean intervals between surgery and study were 33 and 37 months, respectively, for digit replantation and toe transplantation. In normal subjects, the sympathetic skin responses recorded from the fingertip were abolished by local anesthesia or cooling of the finger, while those recorded from the palm were not affected. Ischemia of the finger only transiently affected the digit sympathetic skin responses. These data indicate that the digit responses were locally generated and mediated by unmyelinated fibers. After digit replantation, the palm and digit sympathetic skin responses were not different between replanted and normal sides. After toe transplantation, palm sympathetic skin responses were normal, but digit ones had prolonged latency and reduced amplitude. The present findings suggest that recovery of sympathetic sudomotor activity can be nearly complete in digit replantation but less satisfactory in toe transplantation.

Adolescent↗
PubMed1996

Carbon disulfide induced polyneuropathy: sural nerve pathology, electrophysiology, and clinical correlation.

We report the clinical features, electrophysiological studies, sural nerve pathology and recovery course of carbon disulfide-(CS2) induced polyneuropathy in a 48-year-old man who worked in a viscose rayon plant. Sural nerve biopsy 2 years later still showed degeneration of both axon and myelin with a predominant loss of large myelinated fibers and remyelination. Electrophysiologic studies revealed mixed axonal and demyelinating polyneuropathy. To our knowledge, this is the first human report of sural nerve pathology in the recovery stage due to CS2 intoxication. After diagnosis, the patient was removed from the toxic environment. In the following three years, he showed part recovery predominantly in motor function compatible with the serial nerve conduction studies. We conclude that CS2 polyneuropathy may partly recover years after cessation of exposure.

Axons↗
PubMed1996

Recurrent hypokalemic muscle weakness as an initial manifestation of Wilson's disease.

A 24-year-old man had several episodes of hypokalemic muscle weakness of undetermined etiology since the age of 13 years. Wilson's disease (WD) was not diagnosed until the age of 18 when wing-beating tremor in the left upper limb was noted. Renal function study revealed incomplete proximal renal tubular acidosis. The hypokalemic muscle weakness and wing-beating tremor had subsided after long-term penicillamine therapy. The present case indicates that recurrent hypokalemic paralysis due to renal tubular acidosis is a rare initial presentation of WD and may respond to penicillamine therapy.

Acidosis, Renal Tubular↗