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Biomedical subjects

W H Chen

Publications and source records attributed to W H Chen.

At least 37 records · Page 2Linked to original sources
PubMed2001

Heroin-induced rhabdomyolysis as a cause of reflex sympathetic dystrophy.

Reflex sympathetic dystrophy is an excessive or abnormal response of the sympathetic nervous system in an extremity to an injury or other condition. The authors describe a 37-year-old man who experienced constant pain and vasomotor instability in both feet after nontraumatic rhabdomyolysis secondary to smoking heroin. Three-phase bone scintigraphy was performed and revealed significantly increased blood-flow, blood-pool, and delayed-phase radioactivity. The follow-up three-phase bone scinitigram showed less radiotracer uptake that was consistent with a good response to calcitonin therapy. Heroin-induced rhabdomyolysis should be added to the list of precipitating conditions that can induce this syndrome.

Adult↗
PubMed2001

Comparison of transcranial color-coded sonography and magnetic resonance angiography in acute ischemic stroke.

BACKGROUND AND PURPOSE: This study was designed to assess the accuracy of transcranial color-coded sonography (TCCS) as compared to magnetic resonance angiography (MRA) for detecting intracranial arterial stenosis in patients with acute cerebral ischemia. METHODS: The authors prospectively identified 120 consecutive patients admitted with acute ischemic stroke and performed both TCCS and MRA with a mean interval of 1 day. TCCS data (sampling depth, peak systolic and end diastolic angle-corrected velocity, mean angle-corrected velocity, and pulsatility index) for middle cerebral arteries (MCAs) were compared to MRA data and classified into 4 grades: normal (grade 1): normal caliber and signal; mild stenosis (grade 2): irregular lumen with reduced signal; severe stenosis (grade 3): absent signal in the stenotic segment (flow gap) and reconstituted distal signal; and possible occlusion (grade 4): absent signal. The cutoffs were chosen to maximize diagnostic accuracy. RESULTS: Interobserver agreement for MRA grading resulted in a weighted-kappa value of 0.776. The rate of poor temporal window was 37% (89/240). Doppler signals were obtained in 135 vessels, and the angle-corrected velocities (peak systolic, end diastolic, mean) were significantly different (P = .001, P = .006, and P < .001) among the MRA grades: grade 1 (100, 47, 68 cm/s), grade 2 (171, 72, 110 cm/s), grade 3 (226, 79, 134 cm/s), grade 4 (61, 26, 39 cm/s). Additionally, an angle-corrected MCA peak systolic velocity > or = 120 cm/s correlates with intracranial stenosis on MRA (grade 2 or worse) with high specificity (90.5%; 95% confidence interval = 78.5%-96.8%) and positive predictive value (93.9%) but relatively low sensitivity (66.7%; 95% confidence interval = 61.2%-69.5%) and negative predictive value (55.1%). CONCLUSION: Elevated MCA velocities on TCCS correlate with intracranial stenosis detected on MRA. An angle-corrected peak systolic velocity > or = 120 cm/s is highly specific for detecting intracranial stenosis as defined by significant MRA abnormality.

Acute Disease↗
PubMed2001

Plasmapheresis in the treatment of ataxic sensory neuropathy associated with Sjögren's syndrome.

Sjögren's syndrome (SS) is an important but poorly recognized cause of peripheral neuropathy. Several forms of peripheral nerve dysfunction occur, including trigeminal sensory neuropathy, mononeuropathy multiplex, distal sensorimotor polyneuropathy and pure sensory neuronopathy. The pathological findings vary and the definite treatment is not known. Here we present 4 cases of acute ataxic sensory polyneuropathy with SS, and the experience of treatment with plasmapheresis (PP). The 4 patients were all females; ages ranged from 30 to 58 years. All had prominent loss of kinesthetic and proprioceptive sensation. The course ranged from acute to subacute onset. Patients were treated with 5-9 sessions of PP. Two patients with initiation of treatment within 2 weeks of onset showed dramatic and sustained responses after PP, while the other 2 had no detectable effects. Our experience showed that PP should be considered in patients who present with sensory neuropathy associated with SS, and the treatment should be given as early as possible.

Adult↗
PubMed2001

An unusual increase of blood anti-beta 2-glycoprotein-I antibody but not antiphospholipid antibody in cerebral ischemia--a case report.

An abnormal increase in anti-beta2-glycoprotein I antibodies (abeta2GPI) is capable of producing thrombosis and the vasculopathy-simulating antiphospholipid antibody (aPL). However, it is rarely described in cerebral ischemia without an association with aPL. The authors report a middle-aged man who experienced recurrent cerebral ischemia and diffuse cerebral stenosis without the apparent traditional cardiovascular risk factor. He was free of antiphospholipid/cofactor syndrome (APCS) and systemic lupus erythematosus (SLE). An increase of blood abeta2GPI was detected in serial measurements. The aPL, Venereal Disease Research Laboratory (VDRL) test, Coombs' test, and antinuclear factor were negative. Activated partial thromboplastin time was normal. This patient is a reminder to consider abeta2GPI in an unexplained recurrent cerebral thrombosis and cerebral artery stenosis even when the typical clinical manifestation or laboratory data of APCS is absent.

Antibodies, Antiphospholipid↗
PubMed2001

Bethlem myopathy in a Taiwanese family.

We report three cases of Bethlem myopathy from three consecutive generations of a Taiwanese family, including one woman aged 70, one man aged 40, and a boy aged 8. The clinical features of the patients included autosomal dominant inheritance, childhood or adolescent onset, mainly proximal and extensor involvement, early diffuse joint contractures, and absence of cardiac involvement. These features fulfilled the diagnostic criteria for Bethlem myopathy. Though the clinical course of the disease was once thought to be benign, our female patient became wheelchair-bound at the age of 53. This suggests that the disease process in Bethlem myopathy is slow but ongoing.

Adult↗
PubMed2001

Minilaparotomy for internal drainage of a symptomatic lymphocele after renal transplantation.

Development of a lymphocele after renal transplantation is a well-described complication that occurs with relative frequency. Management options include simple aspiration with sclerotherapy and operative marsupialization of the lymphoceles into the peritoneal cavity. Laparoscopic internal drainage has been favored in recent reports. Still, the laparoscopic procedure is associated with a number of potential problems, including difficulty in localizing lymphoceles if laparoscopic ultrasound is unavailable. In addition, lobulated lymphoceles are more difficult to completely dissect with laparoscopy, and lymphoceles always occur on the anterior and medial aspects of the graft which are easily approached directly from the anterior skin. We tried to resolve these complications by modifying traditional laparotomy and proved that laparoscopy is a progressive, popular procedure, and that fenestration with finger dissection of the lobulated lymphoceles through minilaparotomy is still a reliable, effective procedure.

Adult↗
PubMed2000

Transtentorial cerebellar c-jun expression after focal cerebral cortical injury in mice.

Delayed and remote effect of focal cerebral cortical lesion on cerebellum remains unclear. The c-Jun, an inducible transcription factor of cellular immediate early gene, is the predominant transcription factor and consistent marker for neurons that respond to stress or injury. We use a mouse cryogenic injury model to study the spatial and temporal changes of c-jun in the cerebellum after focal neocortical lesion. A transient and moderate expression of c-jun mRNA was found in the cerebellum with central dominance since 3 day postinjury and gradually subsided within 2 weeks. A distinct increment of c-Jun protein expression in Purkinje cells of the bilateral cerebellar hemispheres with focal connotation in the vermis was detected since 1 week postinjury. These findings suggest that the delayed and remote c-jun expression of the cerebellum, functionally connected with the cerebral cortex, indicate transneuronal gene activation.

Animals↗
PubMed2000

The six year experience of plasmapheresis in patients with myasthenia gravis.

Plasmapheresis (PP) effectively removes autoantibodies in various autoimmune diseases. The use of PP in the treatment of myasthenia gravis (MG) has been widely accepted since the 1970s. The treatment protocol, however, has not been standardized. For the last 6 years, we collected a total of 94 MG patients, 38 males and 56 females aged 14-80 years, who received 175 courses of PP treatment for a total of 823 sessions. The methods we used were double filtration plasmapheresis (DF), immunoadsorption plasmapheresis (IA), and plasma exchange (PE). There were 167 courses of DF, 6 courses of IA, and 2 courses of PE. Each course of treatment consists of 4 to 5 sessions of apheresis. The processed volume of plasma is 1 calculated plasma volume. All patients tolerated PP well although 2.3% of them experienced hypotension. Our experiences are summarized as follows. Both DF and IA effectively ameliorate symptoms and signs of MG. IA removes acetylcholine receptor antibody more effectively than DF does, but clinical effects between these 2 methods are similar. A daily schedule seems more effective than an alternate daily schedule. The optimal number of PP sessions for each course is 4. The factors correlating with better clinical response are high MG score, nonthymoma patients, younger age at onset, and higher removal rate for immunoglobulin G.

Adolescent↗
PubMed2000

An abnormal cholesterol profile in young adults with normocholesterolemic cerebral ischemia.

An abnormal cholesterol fraction can still be able to provoke cascades of lipidic atherogenesis even when the serum TC level is within normal range (< 200 mg%). However, there is a shortage of convincing data concerning cerebral atherogenesis in young Asians who have a different diet habit and living style from those in western countries. In this study, we examined the lipoprotein-cholesterol profile in young Taiwanese patients with noncardiac cerebral ischemia (NCCI) whose serum TC level was < 200 mg% and 200-250 mg%. The results showed a decrease of HDLC and an increase of VLDLC in patients with TC < 200 mg%, but only a decrease of HDLC in patients with TC = 200-250 mg%. The cholesterol fraction metabolism is obviously perplexed in NCCI subjects. These findings were not related to their associated risk factors. Accordingly, a derangement of cholesterol fraction with normal serum TC level can also incite lipidic cerebral atherogenesis in young Taiwanese adults. Therefore, a detailed evaluation of cholesterol profile should be born in mind in young eastern NCCI patients despite of a normal serum TC level. Tailored measure of diet and living should be modified to prevent lipidic atherogenesis in our society in future.

Adult↗
PubMed2000

[Studies on quantitative chromatographic retention-structure relationships].

Using quantum and molecular mechanics methods, 48 structural descriptors of alkylbenzene compounds such as atomic partial charge, dipole moment, molecular area, molecular volume etc. were calculated. GFA regression methods were applied to build a quantitative chromatographic retention-structure relationships equation. The equation have good fitness and strong predictivity. Principle structural factors that effect chromatographic retention of alkylbenzenes were discussed.

Alkylation↗
PubMed1999

Macrocyclic polyamine as a selective modifier in a bonded-phase capillary column for the electrophoretic separation of aromatic acids.

The use of a macrocyclic polyamine, 28[ane]-N6O2, as a selective modifier in a bonded-phase capillary column for the electrophoretic separation of 14 aromatic acids is described. Parameters that affect the performance of the separations, such as the type of buffer, the pH and concentration of buffer, the applied potential and the injection mode were studied. By changing the buffer pH (4.0-5.0), buffer concentration (10-50 mM) and applied potential (-10 approximately -20 kV), optimum conditions were obtained at -20 kV, using an acetate buffer (20 mM, pH 4.5), hydrodynamic injection with a vacuum at the buffer reservoir on the detector side and detection at 220 nm. The results showed that the separation was effective under these conditions. The plate number was greater than 4 x 10(4) m-l. Due to the wide variation in the mobilities of the test compounds, injection studies suggested that a vacuum at the buffer reservoir on the detector side would produce a result that is more representative of the initial sample composition. Benzoic acid in soy sauce, salicylic acid in Salic ointment and Aspirin were sampled and analyzed using the established conditions.

Acids↗
PubMed1999

Early metabolic inhibition-induced intracellular sodium and calcium increase in rat cerebellar granule cells.

1. Possible mechanisms responsible for the increases in intracellular calcium ([Ca2+]i) and sodium ([Na+]i) levels seen during metabolic inhibition were investigated by continuous [Ca2+]i and [Na+]i measurement in cultured rat cerebellar granule cells. An initial small mitochondrial Ca2+ release was seen, followed by a large influx of extracellular Ca2+. A large influx of extracellular Na+ was also seen. 2. The large [Ca2+]i increase was not due to opening of voltage-dependent or voltage-independent calcium channels, activation of NMDA/non-NMDA channels, activation of the Na+i-Ca2+o exchanger, or inability of plasmalemmal Ca2+-ATPase to extrude, or mitochondria to take up, calcium. 3. The large [Na+]i increase was not due to activation of the TTX-sensitive Na+ channel, the Na+i-Ca2+o exchanger, the Na+-H+ exchanger, or the Na+-K+-2Cl- cotransporter, or an inability of Na+-K+-ATPase to extrude the intracellular sodium. 4. Phospholipase A2 (PLA2) activation may be involved in the large influx, since both were completely inhibited by PLA2 inhibitors. Moreover, melittin (a PLA2 activator) or lysophosphatidylcholine or arachidonic acid (both PLA2 activation products) caused similar responses. Inhibition of PLA2 activity may help prevent the influx of these ions that may result in serious brain injury and oedema during hypoxia/ischaemia.

Animals↗
PubMed1999

Experience of double filtration plasmapheresis in the treatment of Guillain-Barré syndrome.

Therapeutic plasma exchange (TPE) is a standard treatment in Guillain-Barré syndrome. TPE may require exogenous fluid for replacement of plasma and, depending on the equipment used, varying extracorporeal volumes. Potential adverse effects include allergic reaction, infection, and hypotension. From September 1993 to December 1997, we treated 16 patients with Guillain-Barré syndrome by a newly developed method of automated double filtration plasmapheresis (DFPP). Patients (ten males and six females, age ranged from 16 to 73) suffering from acute ascending motor weakness and fulfilling the diagnostic criteria for GBS were chosen for DFPP. Each patient received at least five sessions of apheresis in 7 to 10 days and approximately 2.5 to 3.0 L of plasma was treated in each session. Patients were evaluated by disability grade according to a Hughes scale. The mean grade of disability was 3.62 at treatment and improved to 2.37 four weeks after the start of DFPP. The median time to grade 2 (walk without support) was 19 days. There were five patients (41.6%) in need of respirator support. The median time to weaning off the respirator was 9 days. Only two patients (12.5%) could not reach grade 2 at the end of 6 months. Our results were comparable to previously published results of TPE. We conclude that DFPP may be as effective as TPE in the treatment of GBS.

Adolescent↗
PubMed1999

Intracervical misoprostol as an effective method of labor induction at term.

OBJECTS: The purpose of this study was to evaluate the safety and effectiveness of intracervical misoprostol for the induction of labor at term. METHODS: Eighty-nine term pregnancies requiring induction of labor were treated intracervically with 50 microg of misoprostol. The dose was repeated every 4 h until adequate uterine contraction and cervical dilatation were achieved. Status of cervical ripening, uterine contraction, cervical dilatation, labor course and side effects were recorded and analyzed. RESULTS: Among the 89 patients, 58 had an unfavorable cervix (Bishop score < or = 4) and 31 had a favorable cervix (Bishop score > 4). Labor was successfully induced in all cases, most (93.3%) of which required a single dose of misoprostol. Seventy-two patients (81%) proceeded to spontaneous vaginal delivery, and 61 (85%) deliveries were achieved within 12 h. The other 17 cases received cesarean delivery with indications of fetopelvic disproportion (six cases), failure of induction (seven cases) and acute fetal distress (four cases). The mean duration from induction to regular uterine contraction and to delivery was 483+/-537 min and 79.2+/-38.2 min, respectively, with no significant difference between the two groups with differing status of cervical ripening. Complications of uterine contraction, including tachysystole (15 cases), hypertonus (one case) and hyperstimulation (10 cases) were more common in the group of unfavorable cervix (45%) than that of favorable cervix (23%) (P < 0.05). CONCLUSION: In addition to the oral and intravaginal routes of administration, intracervical misoprostol at a single dose of 50 microg appears to be an effective method for induction of labor at term, but caution should be taken with cases with unfavorable cervix.

Abortifacient Agents, Nonsteroidal↗
PubMed1999

A novel effect of cyclic AMP on capacitative Ca2+ entry in cultured rat cerebellar astrocytes.

One of the most important intracellular Ca2+ regulatory mechanisms in nonexcitable cells, "capacitative Ca2+ entry" (CCE), has not been adequately studied in astrocytes. We therefore investigated whether CCE exists in cultured rat cerebellar astrocytes and studied the roles of cyclic AMP (cAMP) and protein kinase C (PKC) in CCE. We found that (1) at least two different intracellular Ca2+ stores, the endoplasmic reticulum and mitochondria, are present in cerebellar astrocytes; (2) CCE does exist in these cells and can be inhibited by Ni2+, miconazole, and SKF 96365; (3) CCE can be directly enhanced by an increase in intracellular cAMP, as 8-bromoadenosine 3',5'-cyclic monophosphate (8-brcAMP), forskolin, and isobutylmethylxanthine have stimulatory effects on CCE; and (4) neither of the two potent protein kinase A (PKA) inhibitors, H8 and H89, nor a specific PKA agonist, Sp-adenosine 3',5'-cyclic monophosphothioate, had a significant effect on cAMP-enhanced Ca2+ entry. The [Ca2+]i increase was not due to a release from calcium stores, hyperpolarization of the membrane potential, inhibition of calcium extrusion, or a change in pHi, suggesting that cAMP itself probably acts as a novel messenger to modulate CCE. We also conclude that activation of PKC results in an increase in CCE. cAMP and PKC seem to modulate CCE by different pathways.

Animals↗
PubMed1999

Miller Fisher syndrome with central involvement: successful treatment with plasmapheresis.

Miller Fisher syndrome is characterized by external ophthalmoplegia, ataxia, and areflexia. Most researchers favor a peripheral origin while others suggest a brainstem inflammatory lesion or a combination of central and peripheral demyelination. We report 2 cases of Miller Fisher syndrome with the typical triad of ataxia, areflexia, and ophthalmoplegia. Strong clinical evidence of central involvement included initial drowsiness, bilateral Babinski sign, and quadriparesis. Evoked potential studies showed prolongation of central conduction time. Plasmapheresis was performed to relieve respiratory failure in Patient 1 and to shorten the duration of nasogastric tube feeding due to severe bulbar palsy in Patient 2. Significant improvement of electrophysiologic parameters was recorded after plasmapheresis. Abnormal evoked potentials, together with clinical evidence of central nervous system abnormalities, support the hypothesis that there is a combination of peripheral and central involvement in Miller Fisher syndrome in our patients. Plasmapheresis is highly effective in relieving the profound neurological deficits of this atypical syndrome.

Adult↗