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Biomedical subjects

H C Chiu

Publications and source records attributed to H C Chiu.

At least 109 records · Page 6Linked to original sources
PubMed1990

Vibratory perception threshold in diabetic neuropathy.

A total of 263 diabetic patients and 129 normal controls were enrolled in a study of vibratory perception threshold (VPT) using an electromagnetic vibrometer at two sites, the dorsum of the metacarpal bone of the index finger (IF) and the dorsomedial aspect of the metatarsal bone of the great toe (GT). The results showed that the mean values of VPT for both IF and GT were significantly higher in diabetics than in normal subjects. In both control and diabetic groups, the VPT values at GT only were elevated with increasing age. Furthermore, the mean VPTs at both IF and GT were related to the duration of illness and the severity of diabetes mellitus in the patient group. Eighty cases of diabetes mellitus received nerve stimulation tests including motor and sensory nerve conduction velocities of the upper and lower limbs. The results from these cases demonstrated good correlation between VPT and motor conduction velocity (MCV), but not between VPT and sensory conduction velocity (SCV). There was a negative correlation between VPT at IF and median MCV (p less than 0.0005) in the upper limbs, as well as VPT at GT and tibial MCV (p less than 0.0005) in the lower limbs. For clinical applications, VPT values seemed to be more sensitive than MCV in detecting neuropathic change in diabetic patients. Hence, impairment of vibratory perception can be taken as a subtle clinical sign of diabetic neuropathy, and measurement of VPT can be used as an index of a patient's current subclinical state.

Adolescent↗
PubMed1990

Molecular analysis of 25 Chinese families with Duchenne/Becker muscular dystrophy.

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are allelic X-linked progressive neuromuscular diseases. We have collected 25 Chinese families each with at least one DMD/BMD patient for DNA analysis in the Xp21 region. Eight genomic probes, 6 within and 2 flanking the DMD gene, and 7 restriction enzymes were used to detect 9 restriction fragment length polymorphisms (RFLPs): C7-EcoRV, J-Bir-BamHI, pERT87-30-BglII, pERT87-15-BamHI, pERT87-15-XmnI, pERT87-1-XmnI, XJ1.1-TaqI, XJ5.1-SphI, and 754-PstI. From analysis of unrelated subjects, we found that the 4 most informative RFLPs in the linkage study were pERT87-15-XmnI, pERT87-1-XmnI, XJ5.1-SphI and J-Bir-BamHI. Two flanking markers, C7 and 754, were noninformative in most families. Three families (12%) had gene deletion: family M-25 at pERT87-1 to 87-30; M-105 at XJ 5.1, 1.1, pERT87-1, and 87-15; and M-110 at XJ5.1, 1.1, and pERT87-1 to 87-30. Two recombinations were detected: M-10 between C7 and pERT87-15; and M-39 between J-Bir and pERT87-15. In the 25 mothers with affected sons, 2 had gene deletion, 1 was homozygous at all 9 polymorphic loci and the other 22 were heterozygous at more than one locus. Twenty-four at-risk female siblings were studied for carriership. Nine were classified as at high risk of carriership, 13 at low risk of carriership by haplotyping, and the remaining two were uncertain, with one due to recombination and the other to maternal homozygous haplotypes. Gene deletion and RFLP analysis are very useful in genetic counseling of Chinese DMD/BMD.

Chromosome Deletion↗
PubMed1990

Cutaneous thermal thresholds in normal subjects and diabetic patients without symptoms of peripheral neuropathy.

An automated system operating on the Peltier principle and using a two-alternative forced-choice testing technique was applied to measure the heat and cold thermal thresholds (HT and CT) in 63 normal subjects and 68 diabetic patients who had no clinical symptoms of peripheral neuropathy. To compare large and small nerve fiber functions, 34 of the diabetic group were also tested for vibration perception threshold (VPT) and nerve conduction velocity (NCV). The testing algorithm of the devices selected for used, including reference temperature and number of turns, was investigated for assessment of variability and reliability. The age effect on thermal thresholds was found in the normal group (p less than 0.001). There was a significant difference between HT and CT in an individual (p less than 0.01). CT was greater than HT in 68% of the subjects. The diabetic group had significantly higher thermal thresholds than the normal group (HT, 0.30 +/- 0.32 degree C vs 0.10 +/- 0.05 degree C, p less than 0.005; CT, 0.39 +/- 0.43 degree C vs 0.15 +/- 0.09 degree C, p less than 0.005). Thermal thresholds greater than the linear regression estimate for age plus three standard errors of estimate were defined as abnormal. The abnormality rate in diabetics was 33.8% for HT and 22.1% for CT. Of the 34 patients, 91.1% had abnormal results in at least one of the three tests: 47.1% abnormal for HT or CT, 67.6% for VPT, and 26.4% for NCV. No correlation existed between the thermal threshold and VPT (p greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Association of HLA antigens with myasthenia gravis in Chinese on Taiwan.

HLA phenotypes were studied in 82 Chinese patients with myasthenia gravis (MG) and 202 healthy controls, using standard microcytotoxicity assay. The patients showed significant increase in HLA-Bw46 (46.3% vs 17.3%, chi 2 = 25.7, p less than 0.001), HLA-DR9 (56.1% vs 15%, chi 2 = 35.7, p less than 0.001) and HLA-DQw3 (89% vs 63.6%, chi 2 = 15.9, p less than 0.001). The HLA-DR3 was decreased (2.4% vs 32.7%, chi 2 = 27.0, p less than 0.001). Both HLA-Bw46 and -DR9 were increased in all subgroups except the over 40 at age of onset group. In thymectomised patients, no association with HLA antigen was found in the thymoma group, whereas both involuted and hyperplasic thymus groups had HLA DR9 association and only the hyperplasic thymus group showed HLA Bw46 association. No association with HLA antigens was noted in patients with low antibody titer, however, patients with antibody titers between 0.2 to 2 n mole/1, had an association with HLA Bw46 and DR9. The HLA DQw3 was associated with the group of female MG patients, age onset below 10 and with ocular myasthenia. Finally, the HLA A2, Bw46 and DR9 combination was also significantly increased in patients [24.3% (20/82) vs 7.4% (8/107), chi 2 = 10.5, p less than 0.001], especially in the subgroup of male MG, age onset below 10 and with ocular myasthenia.

Asian People↗
PubMed1990

The effects of myasthenic immunoglobulin G on the ultrastructure of mouse motor endplate.

The effects of immunoglobulin G (IgG), taken from a patient with myasthenia gravis (MG), were studied on the ultrastructure of mouse diaphragm. IgG from a normal patient served as control. After chronic intraperitoneal injection of IgG isolated from the normal patient, the axon terminal of the mouse diaphragm was filled with numerous synaptic vesicles, mitochondria as well as occasional bundles of fine neurofilaments and neurotubules. Primary and secondary synaptic clefts appeared normal. Similar results showed in the axon terminal of the mouse chronically injected with IgG from MG patient. No significant ultrastructure changes were found in the motor endplate of mouse injected chronically with IgG from a MG patient compared with the motor endplate of mouse injected chronically with IgG from normal patient. It is postulated that IgG from MG may not exert morphological changes on the mouse diaphragm, even after chronic intraperitoneal injection.

Animals↗
PubMed1990

[Cerebrospinal fluid study in Chinese patients with multiple sclerosis].

The demonstration of intrathecally synthesized IgG had been known to be one of the most important aids in diagnosis of multiple sclerosis (MS). Three quantitative methods (CSF IgG, IgG index, de novo IgG synthesis rate) and qualitative detection of oligoclonal band (OB) were used in this study. We collected CSF and serum samples from 22 patients, including 14 with clinically definite MS (DMS) and 8 with clinically possible MS (PMS). The 3 quantitative CSF IgG index were significantly increased in DMS group (p less than 0.05) as compared with normal control group, but not in PMS group. There was no difference in the positive rate of OB between DMS and PMS (both are 50%). The relationship between IgG index and various clinical condition in DMS patients are as following: The 3 CSF IgG index were increased only in the patients with younger age onset, shorter duration, higher relapsing rate, spinal form and disease in relapsing stage. The positive rate of OB was increased only in the patients with longer duration and higher relapsing rate. The follow-up study showed the presence of OB was not change while the disease was remissive. It was concluded that CSF IgG, IgG index, de novo IgG synthesis rate had good correlation with clinical diagnosis, and were good reference for clinical course, disease activity, and therapeutic effect in Chinese patients with MS.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Short- and long-latency median nerve somatosensory evoked potentials in stroke patients.

Short- and long-latency somatosensory evoked potentials (SEPs) were elicited by stimulation of the median nerve in 104 stroke patients, 59 men and 45 women. Their ages ranged from 25 to 90 years, with a mean age of 68 years. All of the patients presented with acute unilateral motosensory or sensory deficits. Based on CT findings, the patients were divided into four groups: thalamic hemorrhage (52 cases), thalamic infarct (21 cases), putaminal hemorrhage or infarct (13 cases) and infarction in the corona radiata or subcortical white matter (18 cases). The criteria for abnormal SEP responses were as follows: (1) absence of N18, (2) prolongation of central conduction time, (3) delay in peak latency of N32, (4) delay in peak latency of N60, and (5) decrease in response amplitude. In patients with thalamic stroke, the abnormality rate of SEPs was 93% (68 out of 73 cases). When the lesions were located primarily in the posterolateral thalamus, all SEP components, particularly the N18 (short-latency) component, were affected. Lesions in other thalamic areas caused changes in the N32 (mid-latency) and the N60 (long-latency) components. In putaminal, corona radiata and subcortical lesions, the abnormality rate of SEPs was 84% (26 out of 31 cases). The N18 component was absent in 3 patients with putaminal hemorrhage. Infarct in the corona radiata and subcortex tended to affect the mid- and long-latency components with relative preservation of the short-latency components.

Adult↗
PubMed1989

Myasthenia gravis and insulin-dependent diabetes mellitus in two adolescents.

Insulin-dependent diabetes mellitus (IDDM) has rarely, if ever, been reported to be an autoimmune disease associated with myasthenia gravis (MG). Two Chinese patients, one of whom was successfully treated with cyclosporin A (CyA) are reported, with discussion of pathophysiologic mechanisms involved and rationale for the treatment used.

Adolescent↗
PubMed1988

Waldenstróm's macroglobulinemia with peripheral neuropathy--the role of IgM M-protein in autoimmune mechanism.

A total of 11 cases of Waldenstróm's Macroglobulinemia (WM) have been investigated to study the association of the disease with neuropathy. A 53-year-old female patient (Wu) had a pronounced peripheral neuropathy, in which the role of IgM M-protein could be observed. Sections of Wu's biopsied sural nerve were subjected to light and electron microscopy and direct immunofluorescence (IF). Myelin degeneration with axonal change was found, while fluorescence reaction occurred in epineurium only. Sections of a healthy dog's sciatic nerve were submitted to purified IgM M-proteins from Wu and another WM patient (Kon) without neuropathy, respectively. Indirect IF showed a deposit of fluorescence on the myelin sheath by Wu's, but not by Kon's, M-proteins. It is proposed that an autoimmune mechanism underlies the peripheral neuropathy in the WM patient.

Animals↗
PubMed1987

Myasthenia gravis: population differences in disease expression and acetylcholine receptor antibody titers between Chinese and Caucasians.

Clinical features and anti-acetylcholine receptor (AChR) titers were compared in Chinese (n = 258) and Caucasian (n = 258) myasthenia gravis populations. The former had more early onset and ocular cases, lacked the Caucasian late onset peak, and had fewer severe cases. The distribution of anti-AChR titers was broadly similar in the two populations, and their sera reacted equally well with AChR in both races. The significantly lower (chi 2 = 14.6; p less than 0.001) median anti-AChR titer in the Chinese population can be accounted for by the higher frequency of ocular cases and lower frequency of moderate or severely affected cases.

Adolescent↗
PubMed1987

Epitope mapping of functional domains of human factor Va with human and murine monoclonal antibodies. Evidence for the interaction of heavy chain with factor Xa and calcium.

We have purified a unique neutralizing IgG1, kappa monoclonal antibody (MAb) against factor V (F-V) from a patient's plasma. This MAb (H2) demonstrated specificity for human F-V heavy chain (D), mol wt 105,000. Using an enzyme-linked immunosorbent assay (ELISA) we assessed the competitive binding to F-Va of H2, H1 (human MAb directed to light chain, F1F2), and two murine MAbs, B38 (to F1F2) and B10 (to activation peptide C1). All four antibodies are of high affinity with KD varying from 0.17 to 1.17 X 10(-10) mol/L. They recognized distinct epitopes in F-V. F-Xa competed in a concentration-dependent fashion for binding of H1, H2, and B38 but not B10 to F-V/Va in the absence of phospholipids or platelets. Thus both F1F2 and D polypeptides of F-Va but not C1 interacted with F-Xa. All MAbs bound to F-V/Va in the absence of Ca++. However, free Ca++ (0.1 to 4.0 mmol/L) increased the amount of H1 and H2 bound to factor V/Va, 1.65-fold and 3.65-fold, respectively but had little effect on the binding of either murine MAbs. Prothrombin (20 micrograms/mL to 400 micrograms/mL) in the absence of phospholipid did not inhibit the binding of MAbs. These studies provide evidence for the first time for a direct interaction between human F-Va heavy chain and F-Xa and Ca++ and for the direct binding of F-Xa to F-Va in the absence of phospholipids or platelets and enhance our understanding of functional F-V domains.

Alkaline Phosphatase↗
PubMed1987

The effects of myasthenic immunoglobulin G on neuromuscular transmission in mouse diaphragm.

The effect of immunoglobulin G (IgG) from a patient with myasthenia gravis (MG) on neuromuscular transmission of an isolated mouse diaphragm preparation was studied by using electrophysiological methods. The frequency and amplitude of miniature endplate potentials (MEPPs) of the diaphragms obtained from mice injected intraperitoneally with purified IgG from MG patient were reduced by about 13% and 20%, respectively in comparison with results from normal mouse diaphragms. The amplitude of endplate potential (EPP) and the quantal content of EPPs were also reduced by about 21% and 7%, respectively. No significant changes in EPP and MEPP amplitudes were seen in the diaphragms of mice injected with normal IgG serum. It is postulated IgG from myasthenia gravis acts to interfere with both the receptor and the nerve terminal functions.

Animals↗