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Biomedical subjects

Wei-Hung Chen

Publications and source records attributed to Wei-Hung Chen.

At least 19 recordsLinked to original sources

Simplified electrodiagnostic criteria of diabetic polyneuropathy in field study (KCIS No. 14).

This study sought to determine the sensitivity of sural sensory action amplitude (SAP) and peroneal motor conduction velocity (MCV) for differentiating the status of other nerve conduction velocities and identifying important correlates of diabetic polyneuropathy. Subjects (n = 708) with type 2 diabetes from one community completed a preliminary questionnaire. Among the 298 subjects with positive questionnaire results, 272 completed nerve conduction tests. The means of 6 nerve conduction velocities of subjects with both SAP and MCV abnormalities were compared to those of normal controls. The mean conduction velocities of all motor and sensory nerves were slower (p < 0.05) in subjects with polyneuropathy than without polyneuropathy. Important known correlates of diabetic polyneuropathy can also be identified by this electrophysiological definition. The sural SAP and peroneal MCV together serve as a good diagnostic for diabetic polyneuropathy and can be used as a simplified criterion in field studies.

Action Potentials↗

Hemolysis in double-filtration plasmapheresis.

To evaluate the occurrence of hemolysis during double-filtration plasmapheresis (DFP) treatment and its causes, we prospectively treated 113 myasthenic patients and monitored transmembrane pressure (TMP), arterial line pressure (Pa), and venous line pressure (Pv) at 30-minute intervals (M30, M60, M90, and M120) during treatment. Laboratory and clinical parameters related to the development of hemolysis were also analyzed. The overall frequency of hemolysis was 35.4%. Peripheral venous access was associated with a higher rate of hemolysis (45.3%) The mean TMP increased significantly after M30 for the hemolysis group compared with the no hemolysis group. A similar trend was present for Pa. Pv did not differ between the 2 groups during treatments until M90 and M120. Pa and TMP changed significantly with time (both P < .0001). Vascular access through large veins and stable TMP during the procedure may help avoid hemolysis.

Adolescent↗

High titer of anticardiolipin antibody is associated with first-ever ischemic stroke in Taiwan.

BACKGROUND AND PURPOSE: The association between anticardiolipin antibody (aCL) and ischemic stroke is controversial, and there are few case-control studies of Asian populations. The aim of this study, therefore, was to determine whether aCL is an independent risk factor for ischemic stroke in Taiwanese patients over the age of 40 years. METHODS: Both the IgG and IgM isotypes of aCL were measured in 273 patients (> 40 years of age) hospitalized for first-ever ischemic stroke and in 181 non-stroke controls. Results were defined as: negative (< 10 IgG phospholipid units [GPL] or < 7.5 IgM phospholipid units [MPL]); low positive (10-20 GPL or 7.5-15 MPL); or, high positive (> 20 GPL or > 15 MPL). Odds ratios (OR) were estimated by logistic regression with adjustment for potential confounders. RESULTS: A high positive IgG aCL was present in 4.4% of the stroke patients and 1.2% of the controls. Age- and sex-adjusted analysis showed a borderline association between a high positive level for aCL IgG titer and stroke, with an OR of 4.01 (95% CI 0.87-18.37; p = 0.0739). Final analysis, with adjustments for age, sex, hypertension, diabetes, tobacco smoking, atrial fibrillation, left ventricular hypertrophy and hyperlipidemia, revealed an OR of 5.25 (95% CI 1.06-25.89; p = 0.0419). CONCLUSIONS: The results of this study suggest that elevated titer of aCL IgG (> 20 GPL) is associated with first-ever ischemic stroke in Taiwanese patients aged over 40 years. High positive aCL titer is related to ischemic stroke after adjustment for conventional cerebrovascular risk factors, indicating that it is probably an independent risk factor for ischemic stroke.

Adult↗

Tissue engineered cartilage using human articular chondrocytes immortalized by HPV-16 E6 and E7 genes.

Chondrocytes are useful as a cell culture system for studying arthritic degeneration in tissue engineered cartilage. However, primary chondrocytes have short in vitro lifespan and rapid shift of collagen phenotype. In this study, we used a high dosage of retroviral vector LXSN16E6E7 to transduce human primary chondrocytes and obtained an actively proliferating cell line, designated hPi, which expresses HPV-16 E6/E7 mRNA in early passages. Parental primary chondrocytes cease to grow after five passages, whereas hPi could be propagated beyond 100 passages without requiring additional cell elements in defined medium. After 48 passages, hPi can also give many profiles similar to those of parental primary chondrocyte, including type II collagen in mRNA and protein level, aggrecan in mRNA level, lacunae in type I collagen matrices, and morphology with GAG-specific Alcian blue staining. hPi has shown neoplastic transformation, as examined by NOD-SCID mice tumorigenicity assays for 3 months. Our results indicated that human primary chondrocytes could be immortalized by transduction with HPV-16 E6/E7, preserving stable cartilage-specific differentiation markers. The established chondrocyte cell line could provide a novel model to engineer cartilage in vitro and in vivo for cartilage repair research and clinical application.

Animals↗

Clearance studies during subsequent sessions of double filtration plasmapheresis.

To evaluate the optimal session of double filtration plasmapheresis (DFP) in terms of the maximal clearance rates for various serum substances, the laboratory parameters of 152 consecutive patients treated with different sessions of DFP following a standard protocol on an alternate-day basis was studied. Immunoglobulin M (IgM) and lipoprotein cholesterol had the most effective clearance by a minimum of two sessions of DFP treatment, and the clearance rates remained relatively constant despite the increase in the number of treatment sessions, while the clearance rates for other serum proteins increased steadily with further treatments. Using the clearance rate of the 2-session group as reference, the highest slopes for clearance of albumin, globulin, and triglyceride were found in the 4-session group, while the slopes for IgA and IgG were highest in the 5-session group. In conclusion, for the clearance of IgM and lipoprotein cholesterol, two sessions of DFP treatment are adequate. However, the best clearance of IgG and other globulins cannot be achieved until the fourth session of DFP treatment. Therefore, a minimum of 4 sessions of DFP treatment at 2-day intervals is needed for most immunological diseases.

Adolescent↗

Delayed hemopericardium with constrictive pericarditis after blunt trauma: a report of a surgical case.

Constrictive pericarditis (CP) following hemopericardium has been reported in the literature but its pathogenesis is open to question. Proposed mechanisms include trauma leading to damage of the mesothelial lining resulting in decreased fibrinolytic activity in the presence of blood. We present a patient who sustained blunt thoracoabdominal trauma in a car accident and subsequently developed delayed hemopericardium leading to constrictive pericarditis and impending cardiac tamponade. We performed a pericardiectomy to relieve the compression. Closely prolonged monitoring and emergent operation are suggested for such kinds of delayed complications.

Adult↗

Efficient and stereodivergent synthesis of deoxyimino sugars.

Both cis- and trans-2-substituted-1,2,3,6-tetrahydro-pyridin-3-ols have been prepared via an aldol condensation-ring-closing metathesis sequence. A stereodivergent synthesis of optionally functionalized deoxyimino sugars was achieved via asymmetric dihydroxylation or epoxidation/nucleophilic substitution of these tetrahydropyridines.

Crystallography, X-Ray↗

Prethymectomy plasmapheresis in myasthenia gravis.

Plasma exchange before thymectomy may decrease the time on mechanical ventilation (MV) and shorten the stay in the intensive care unit (ICU) for patients with myasthenia gravis (MG). This study evaluated the effects of prethymectomy plasmapheresis. A total of 29 myasthenic patients, 18 women and 11 men aged 20-73 years, were treated with double filtration plasmapheresis (DFP) for two to five consecutive sessions over a period between 2 and 21 days (mean 8.1 days) before transsternal thymectomy. Acetylcholine receptor antibody (AchRAb) titers, vital capacity (VC), maximal inspiratory pressure (Pimax), and MG score were measured before and after the course of DFP. Three outcome measures including duration of postoperative hospital stay, duration of ICU stay, and duration of MV were analyzed for correlation with clinical variables. The duration of MV ranged from 6 to 93 h, with a median of 21 h. The median ICU stay was one day and the median postoperative hospital stay was 10 days. A higher removal rate of AchRAb was associated with a shorter duration of ICU and postoperative hospital stay (P = 0.001 and 0.019, respectively). Postoperative hospital stay was strongly correlated with post-DFP Pimax (P = 0.010), and marginally correlated with pre-DFP VC (P = 0.047) and to a lesser extent with pre-DFP Pimax (P = 0.063). Univariate analysis using the log rank test revealed that removal rate of AchRAb <30% (P = 0.043) and pre-DFP Pimax <-60 cmH2O (P = 0.024) were significantly associated with prolonged ICU stay. Risk factors for prolonged postoperative stay included post-DFP Pimax <-60 cmH2O (P = 0.017), pre-DFP Pimax <-60 cmH2O (P = 0.031), and post-DFP VC < 1.0 L (P = 0.046). Our results confirmed the efficacy and safety of DFP in prethymectomy preparation for myasthenic patients.

Adult↗

Distal ulnar neuropathy in a golf player.

A 51-year-old right-handed amateur golfer has developed fasciculations in the left first dorsal interosseous muscle for 3 weeks. He did not have any pain or motor or sensory deficit. The nerve conduction study and electromyography showed that he had mononeuropathy of the deep palmar branch of the ulnar nerve in his left palm. The forceful grasp of golf club handle in the left palm contributes to this rare focal neuropathy. He was advised to change his grip on the golf club, and the symptom resolved almost immediately.

Action Potentials↗

AIDS with acute cerebral infarct: a case report.

A 38 year-old male presented with an acute onset of left hemiplegia. Brain magnetic resonance imaging (MRI) revealed a bright lesion by diffusion-weighted imaging with low apparent diffusion coefficient value in the right subcortical region, a finding compatible with an acute cerebral infarct. An old infarct was also noted in the same imaging. Both enzyme-linked immunosorbent assay and Western blot method were positive for human immunodeficiency virus infection. The white blood cell count was 2930 cells / mm3, and the subpopulation study for lymphocyte revealed a decreased cluster of differentiation 4+ count of 149 cells/mm3. Studies for prothrombotic states showed decreased protein S and increased anticardiolipin antibodies. We concluded that this was a case of acquired immunodeficiency syndrome (AIDS) with acute and old cerebral infarcts. This patient might be the first reported case in Taiwan. AIDS might be related with stroke in young patients, a condition probably under-recognized in Taiwan.

Acquired Immunodeficiency Syndrome↗

Cortical sensory loss in a patient with posterior cortical atrophy: a case report.

Patients with posterior cortical atrophy (PCA) who present with initial symptoms of higher visual function deficits eventually develop alexia, aphasia, and components of Balint's syndrome or Gerstmann's syndrome. Recently, pathological findings were reported for these patients that are generally suggestive of Alzheimer's disease even though Creutzfeldt-Jakob disease (CJD) was presumed as an alternative cause of some autopsy-diagnosed PCA cases. Here, we report a case with a four-year progression of cognitive and higher visual function deterioration, and with features not described in previously reported PCA cases (i.e., a distinct sensory complaint and early frontal lobe involvement). To summarize, this case belongs to perceptual-motor syndrome of asymmetric cortical degeneration and the underlying neuropathology is more suggestive of Alzheimer's disease than of Creutzfeldt-Jakob disease.

Atrophy↗

Complications of double-filtration plasmapheresis.

BACKGROUND: Double-filtration plasmapheresis (DFP) removes high-molecular-weight molecules semiselectively, thereby minimizing albumin loss, but with subsequent need for fluid substitution. The purpose of this study was to establish the overall incidence of complications during DFP and to analyze the possible contributory factors. STUDY DESIGN AND METHODS: From November 1993 to October 2003, a total of 2502 plasmapheresis procedures were performed during 515 courses of plasmapheresis in 335 patients. The medical and technical records for these patients were reviewed. RESULTS: The overall frequency of complications was 67.5 percent per patient, 60.0 percent per course, and 26.3 percent per procedure. The rate of major complications was 18.2 percent of patients, 13.2 percent of courses, and 2.7 percent of procedures. Hemolysis, the most common complication of DFP, occurred in 20 percent of patients. A total of 83 (3.3%) episodes of hypotension were documented in 63 patients. Vascular-access-related complications constituted approximately 17 percent of the total. There was one documented episode of clinically overt bleeding from laboratory coagulopathy necessitating infusion of fresh plasma to stop bleeding. There was no allergic reaction or mortality associated with the DFP procedures. The per-patient frequency of hypotension was higher in cases of chronic inflammatory neuropathy (35.1%) compared to the other illness categories (15.4%-17.3%), with marginal significance demonstrated (p = 0.0611). CONCLUSION: The safety of DFP treatment has been confirmed by this study. High-risk patients should be monitored carefully during treatment to minimize the occurrence of complications.

Guillain-Barre Syndrome↗

[Basic mechanism for generation of brain rhythms].

Study of the basic mechanism of brain rhythms adds to our understanding of the underlying processes of neuronal network within the human brain. Electroencephalography (EEG) records summated extracellular field potentials from large pyramidal neurons in the cerebral cortex. The characteristic rhythmic oscillation of brain rhythms are beststudied by sleep spindles, which are generated within the thalamus through a network of thalamic reticular cells, thalamocortical projection cells and cortical pyramidal cells. Fast rhythms including beta and gammaare present during arousal and focused attention. Besides a reflection of activation from the brainstem reticular activating system, fast rhythms also represent an activated state of the underlying neuronal network. Alpha waves are readily recognized brain waves during relaxed wakefulness; however, the origins of alpha rhythm are not well understood. It is presumed that alpha rhythms are generated by contingent pyramidal cell, and by intracortical connections, spread in the cortical layers. Rhythmic alpha spindles probably represent a de-activated state.

Cerebral Cortex↗