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Biomedical subjects

C C Huang

Publications and source records attributed to C C Huang.

At least 199 records · Page 11Linked to original sources
PubMed1999

Tissue mosaicism in the skeletal muscle and sural nerve biopsies in the MELAS syndrome.

We describe a clinically full-blown MELAS patient, who had an A3243G point mutation of mitochondrial DNA (mtDNA) in muscle and blood cells, and his family members. From the proband two muscle biopsies from the vastus lateralis muscle were analysed; one had typical ragged red fibers and focal cytochrome c oxidase deficiency and the other was completely normal. He also had a peripheral neuropathy confirmed by nerve conduction velocity and sural nerve biopsy studies. Axonal degeneration, relative loss of large myelinated fibers and paracrystalline inclusion bodies in the Schwann cells were noted. Intriguingly, the A3243G mutation of mtDNA was not found in the sural nerve biopsy. Therefore, we conclude that tissue mosaicism is present in the muscle fibers and that the mtDNA mutation may not be detected in the nerve involved as proved by pathology. We also suggest that the involvement of specific tissues in patients with mitochondrial diseases should be further determined by single fiber mtDNA analysis.

Adult↗
PubMed1999

Pulmonary mechanics in patients with prolonged mechanical ventilation requiring tracheostomy.

This study was performed to assess the changes in pulmonary mechanics before and after tracheostomy in patients with prolonged mechanical ventilation and to detect pre-tracheostomy physiologic factors that predict the outcome of weaning from mechanical ventilation. Pulmonary mechanics were recorded before and after tracheostomy in 20 patients. Work of breathing, mean airway resistance and pressure/time product showed no significant differences after tracheostomy. Peak inspiratory pressure was significantly reduced (pre 33.4 +/- 11.8 vs post 28.6 +/- 9.2 mmHg). There was no difference in age or duration of mechanical ventilation between two different groups according to the outcome (weaned and not-weaned). Pre-tracheostomy intrinsic positive end expiratory pressure (PEEPi) was significantly lower in the weaned group (1.1 +/- 1.6 vs 2.7 +/- 1.4 mmHg). A significant difference was also found in pre-tracheostomy compliance (Cstatic) (47.3 +/- 36.9 vs 28.8 +/- 16.5 ml/cmH2O). We concluded that tracheostomy changed pulmonary mechanics very little except for a fall in peak inspiratory pressure. Patients who had better underlying lung mechanics (higher Cstatic and lower PEEPi) had better chances of weaning from mechanical ventilation after tracheostomy.

Adult↗
PubMed1999

Basic fibroblast growth factor in experimental and clinical bacterial meningitis.

Basic fibroblast growth factor (bFGF), a neurotrophic factor in the CNS, is expressed at high levels in response to seizures or strokes. We examined the expression of bFGF during experimental bacterial meningitis and the levels of bFGF in the cerebrospinal fluid (CSF) of children with bacterial meningitis. For the experimental study, a mouse model of meningitis was established by intracranial injection of Streptococcus pneumoniae. Twenty-four hours after induced meningitis, the brains were sectioned and stained immunohistochemically for bFGF. Neutrophils and macrophages infiltrating the leptomeninges and the ventricles exhibited strong bFGF immunoreactivity. The neurons in the areas adjacent to the inflamed ventricles also showed enhanced bFGF expression. For the clinical study, we used an enzyme immunoassay to measure bFGF in CSF in 18 children with bacterial meningitis, 12 with aseptic meningitis, and 18 controls. The CSF levels of bFGF were twice as high in children with bacterial meningitis (medians 6.75-7.21 pg/mL) compared with those who had aseptic meningitis (2.9 pg/mL) or in control subjects (2.65 pg/mL, p < 0.0001, respectively). In patients with bacterial meningitis who survived, CSF bFGF decreased significantly after 24-50 h of antibiotic therapy (p < 0.0005). Patients who developed major sequelae or died had much higher levels of CSF bFGF than those without (134.9 pg/mL versus 7.38 pg/mL, p < 0.05). These findings of enhanced immunoreactivity of bFGF in experimental bacterial meningitis and an association of CSF levels of bFGF with disease severity in childhood bacterial meningitis suggest a biologic role for this neurotrophic factor in the pathophysiology of bacterial meningitis.

Animals↗
PubMed1999

Pre-dialysis glycemic control is an independent predictor of mortality in type II diabetic patients on continuous ambulatory peritoneal dialysis.

OBJECTIVE: To evaluate the impact of pre-dialysis glycemic control on clinical outcomes for type II diabetic patients on continuous ambulatory peritoneal dialysis (CAPD). MATERIALS AND METHODS: One hundred and one type II diabetic patients receiving CAPD for at least 3 months were enrolled in a single institute. The patients were classified into two groups according to status of glycemic control. In the good glycemic control group, more than 50% of blood glucose determinations were within 3.3-11.0 mmol/L and glycosylated hemoglobin (HbA1C) levels were within 5%-10% at all times. In the poor glycemic control group, less than 50% of blood glucose determinations were within 3.3-11.0 mmol/L, or HbA1C levels were above 10% at least 6 months before peritoneal dialysis was started. In addition to glycemic control status, pre-dialysis serum albumin, cholesterol levels, residual renal function, peritoneal membrane function, and modes of glycemic control were also recorded. RESULTS: The patients with good glycemic control had significantly better survival than those with poor glycemic control (p < 0.01). There was no significant difference in pre-dialysis morbidity between two groups. No significant differences were observed in patient survival between patients with serum albumin above 30 g/L and those with serum albumin under 30 g/L; between those with cholesterol levels above or below 5.2 mmol/L; and between those with different peritoneal membrane solute transport characteristics as evaluated by a peritoneal equilibration test (PET). Furthermore, there was no significant difference in survival between patients who controlled blood sugar by diet and those who controlled it by insulin. Cardiovascular disease and infection are the major causes of death in both groups. Although good glycemic control predicts better survival, it does not change the pattern of mortality in diabetic patients maintained on CAPD. CONCLUSIONS: Glycemic control before starting dialysis is a predictor of survival for type II diabetic patients on CAPD. Patients with poor glycemic control predialysis are associated with increased morbidity and shortened survival.

Blood Glucose↗
PubMed1999

Molecular epidemiologic study of mitochondrial DNA mutations in patients with mitochondrial diseases in Taiwan.

We report an 8-year molecular study of mitochondrial DNA (mtDNA) mutations in patients with mitochondrial diseases in Taiwan. One hundred and seventy-seven patients met the diagnostic criteria of mitochondrial disease and were recruited into the study. The results showed that 32 patients, including 25 with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome, one with Kearns-Sayre syndrome (KSS), one with diabetes mellitus and deafness, and five with chronic progressive external ophthalmoplegia (CPEO), harbored the A3243G mtDNA mutation. The A8344G mutation was found in nine patients, all of whom suffered from myoclonic epilepsy and ragged-red fibers (MERRF) syndrome. The G11778A mtDNA mutation was found in 18 of 22 patients with Leber's hereditary optic neuropathy. The T8993C and T8993G mutations were found, respectively, in one and two patients with Leigh syndrome. Large-scale deletions of mtDNA were found in 17 patients with CPEO, one with KSS, one with MELAS, and two with MERRF syndrome. The mtDNA mutations in patients with each of the mitochondrial diseases found in Taiwan were restricted mainly to a single site, while those reported for the same diseases in other ethnic groups occurred in many sites. Furthermore, significant levels of additional mtDNA mutations occurred in some patients with mitochondrial encephalomyopathies. We suggest that these additional (or secondary) mtDNA mutations are generated as a consequence of the preexisting primary mtDNA mutations and may contribute to the age-dependent progressive deterioration characteristic of mitochondrial diseases.

Adolescent↗
PubMed1999

Comparison of indoor allergens, allergic scores, and demographic data in Taiwanese adults with asthma or allergic rhinitis, or both.

We examined the relationships between exposure to different indoor allergens and demographic factors in 515 adult Taiwanese patients with allergic diseases such as asthma and rhinitis. Patients who had positive screening results on an immunoglobulin E (IgE) test were recruited from the outpatient clinics of Chang Gung Memorial Hospital. Patients were divided into the following three groups: asthma (n = 332), combined asthma and allergic rhinitis (n = 165), and allergic rhinitis (n = 18). Serum samples were analyzed for IgE by enzyme-linked immunosorbent assay. Significantly elevated titer of dust mite-specific IgE were found in all three groups, with markedly higher levels in the combined asthma and allergic rhinitis group (p < 0.05). Allergen scores were significantly related to the demographic variables of older age (> or = 65 years), female gender, and spring season, with significantly lower scores (p < 0.05). No significant difference in allergen scores was found among cigarette smoking subjects and subjects from residential areas. Multiple linear regression analysis revealed significant allergic contributors to be, in order of importance, age, gender, and atopic disease category. We conclude that mite allergen exposure is the most significant factor associated with asthma and/or allergic rhinitis in Taiwan. Younger subjects and males had a higher rate of asthma and/or allergic rhinitis.

Adolescent↗
PubMed1999

Tracheal neurilemmoma mimicking bronchial asthma--a dilemma of difficult diagnosis: case report.

Tracheal tumors are often overlooked as a cause of pulmonary symptoms until they reach an advanced state. They are often presented with a prolonged cough and shortness of breath. Most tracheal tumors in adults are cancerous (80% to 90%). Benign tracheal tumors are rare in adult patients. A case history is presented of a 19-year-old patient with a rare tracheal neurilemmoma. He was treated as having bronchial asthma initially, but his signs and symptoms did not improve with traditional therapy. The possibility of the presence of an upper airway obstruction was not raised until the typical "inspiratory tubular sound" was heard. Flow-volume loop testing, bronchoscopy, and three-dimensional computed tomography (3-D CT) confirmed the diagnosis of upper airway obstruction caused by a tracheal tumor. Therefore, surgical intervention rather than bronchoscopic removal was performed without difficulty. The patient was leading a stable life 8 months after a surgical resection. The presence of an upper airway obstruction can be proven by flow-volume loop testing and 3-D CT. Further pathologic confirmation can be accomplished by bronchoscopy. High suspicion of an upper airway obstruction such as a tracheal lesion should be raised when bronchial asthma patients fail to respond to conventional treatment.

Adult↗
PubMed1999

Hepatocellular carcinoma with mediastinal and pericardial invasion: report of two cases.

Mediastinal invasion with pericardial involvement in hepatocellular carcinoma (HCC) is rarely described. We report two patients with hepatitis-C-related HCC, who, after several courses of transcatheter arterial chemoembolization (TACE), developed mediastinal and pericardial neoplastic growth. Both patients presented with clinical manifestations of exertional dyspnea, chest pain and orthopnea. The diagnosis of HCC with pericardial involvement, through direct invasion of the anterior mediastinum, was established by computerized tomography and magnetic resonance imaging. These patients' symptoms were relieved after they received radiotherapy with a total dosage of 3,000 and 4,000 cGy over a three-week and four-week period, respectively. We suggest that direct mediastinal invasion with pericardial involvement should be considered when evaluating patients with advanced HCC who developed precordial distress following palliative TACE. Early recognition of this unusual complication is important in the management of HCC.

Aged↗
PubMed1999

[Hypothyroid myopathy: a case report].

Though proximal muscle weakness is characteristic of polymyositis, other agents may also lead to proximal muscle weakness, such as drugs, endocrine diseases, or infections. Here, we report a thirty year-old female suffering from proximal weakness which initially was thought to be a case of polymyositis with high serum creatine phosphokinase level. Very low thyroid hormone levels were found as the history inquiry revealed constipation, hoarseness and cold intolerance. The muscle biopsy showed no obvious inflammation. After thyroxine therapy, her muscle weakness recovered. Up to now, hypothyroid myopathy with muscle mitochondrial abnormalities shown by electron microscopic examination has not been reported in the medical literature in Taiwan. Hypothyroid myopathy, though it is rare, may be misdiagnosed as polymyositis clinically. Therefore, it is recommended that hypothyroid myopathy should be considered in the differential diagnosis of proximal muscle weakness.

Adult↗
PubMed1998

Generation of destabilized green fluorescent protein as a transcription reporter.

The green fluorescent protein (GFP) is a widely used reporter in gene expression and protein localization studies. GFP is a stable protein; this property allows its accumulation and easy detection in cells. However, this stability also limits its application in studies that require rapid reporter turnover. We created a destabilized GFP for use in such studies by fusing amino acids 422-461 of the degradation domain of mouse ornithine decarboxylase (MODC) to the C-terminal end of an enhanced variant of GFP (EGFP). The fusion protein, unlike EGFP, was unstable in the presence of cycloheximide and had a fluorescence half-life of 2 h. Western blot analysis indicated that the fluorescence decay of EGFP-MODC-(422-461) was correlated with degradation of the fusion protein. We mutated key amino acids in the PEST sequence of EGFP-MODC-(422-461) and identified several mutants with variable half-lives. The suitability of destabilized EGFP as a transcription reporter was tested by linking it to NFkappaB binding sequences and monitoring tumor necrosis factor alpha-mediated NFkappaB activation. We obtained time course induction and dose response kinetics similar to secreted alkaline phosphatase obtained in transfected cells. This result did not occur when unmodified EGFP was used as the reporter. Because of its autofluorescence, destabilized EGFP can be used to directly correlate gene induction with biochemical change, such as NFkappaB translocation to the nucleus.

Amino Acid Sequence↗
PubMed1998

H-Ras peptide and protein substrates bind protein farnesyltransferase as an ionized thiolate.

The zinc metalloenzyme protein farnesyltransferase (FTase) catalyzes the alkylation of a cysteine residue of protein substrates with a 15 carbon farnesyl group. We have developed fluorescence assays to directly measure the affinity of the enzyme for peptide and protein (Ras) substrates. A peptide corresponding to the carboxyl terminus of H-Ras binds to FTase in the microM range (KD = 4 microM) at physiological pH; however, the peptide affinity is enhanced approximately 70-fold in a ternary complex with an enzyme-bound farnesyl diphosphate (FPP) analogue, indicating that the two substrates bind synergistically. The pH dependence of substrate binding was also investigated, and two ionizations were observed: for the ternary complex, the pKa values are 8.1, reflecting ionization of the thiol of the free peptide, and 6.4. The pH dependence of the ligand-metal charge-transfer band in the optical absorption spectra of a Co2+-substituted FTase ternary complex suggests that a metal-coordinated thiol ionizes with a pKa of 6.3. These data indicate that metal coordination of the peptide sulfur with the zinc ion in FTase lowers the pKa of the thiol resulting in formation of a bound thiolate at physiological pH.

Alkyl and Aryl Transferases↗
PubMed1998

Protein kinase C inhibitors block generation of anoxia-induced long-term potentiation.

The aim of this study was to study the possible intracellular mechanisms underlying the anoxia-induced long-term potentiation (anoxic LTP) in the CA1 neurons of rat hippocampal slices using extra- and intracellular recording techniques. Superfusion of the hippocampal slices with the protein kinase C (PKC) inhibitors NPC-15437 (20 microM) or H-7 (20 microM) specifically prevented the induction of anoxic LTP. Moreover, the anoxic LTP was completely abolished in neurons intracellularly recorded with the selective PKC inhibitor PKCI 19-36 (50 microM). The specific cAMP-dependent protein kinase (PKA) inhibitor Rp-cyclic adenosine 3',5'-monophosphate (Rp-cAMPS, 25 microM) had no effect on the anoxic LTP. It is concluded that induction of anoxic LTP requires the activation of postsynaptic PKC.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1998

Potentiation of N-methyl-D-aspartate currents by isoproterenol in the acutely dissociated rat amygdalar neurons.

Whole-cell patch-clamp recordings in the acutely dissociated amygdalar neurons were performed to investigate the effect of isoproterenol (Iso) on NMDA currents. Bath application of Iso selectively enhanced the NMDA currents without affecting the AMPA currents. Iso potentiated the NMDA currents to the same extent at various holding potentials and the reversal potential for the NMDA response was not altered. These results suggest that adrenergic innvervations in this area may play an important role in synaptic plasticity.

Amygdala↗
PubMed1998

Urinary levels of inorganic and organic arsenic metabolites among residents in an arseniasis-hyperendemic area in Taiwan.

In order to elucidate whether urinary levels of inorganic and organic arsenic metabolites are associated with previous exposure to high-arsenic artesian well water, a total of 302 residents of age 30 yr or older were recruited from three arseniasis-hyperendemic villages in Taiwan. Most study subjects had stopped consuming high-arsenic artesian well water for more than 20 yr. The mean total arsenic (Ast) determined by inductively coupled plasma mass spectrometer (ICPMS) was 267.05 +/- 20.95 microg/L, and the mean level of inorganic arsenic and its metabolites (Asi) was 86.08 +/- 3.43 microg/L. In the multivariate analysis, urinary dimethylarsinic acid (DMA) levels were significantly inversely associated with age, with women exhibiting significantly lower urinary amounts of arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMA), organic arsenic (Aso), and Ast compared to men. After adjustment for age and sex, previous cumulative arsenic exposure through consumption of artesian well water was significantly associated with elevated urinary levels of MMA and DMA, but not As(III) + As(V), Aso and Ast. In the multivariate analysis, the percentage of Aso in Ast was significantly higher in men than women, but this was not significantly associated with age. The percentage of As(III) + As(V) in Asi increased significantly with age, while the reverse was noted with DMA in Asi. Women had a significantly higher DMA percentage but lower As(III) + As(V) and MMA percentages in Asi than men. After adjustment for age and sex, the percentages of As(III) + As(V) in Asi were significantly inversely associated with previous arsenic exposure through consumption of artesian well water. Data suggested that women seem to possess a more efficient arsenic methylation capability than men, and aging diminishes this methylation capability; furthermore, the higher the cumulative arsenic exposure, the greater is the body burden of inorganic arsenic, mainly in the form of MMA and DMA.

Adult↗
PubMed1998

Selective enhancement of P-type calcium currents by isoproterenol in the rat amygdala.

We investigated activation of beta-adrenergic receptor-adenylyl cyclase-cAMP cascade on the whole-cell voltage-dependent Ca2+ currents (ICa) in acutely isolated rat basolateral amygdala neurons. Application of beta-receptor agonist isoproterenol (Iso) caused a long-term enhancement of ICa. The effect of Iso was blocked by concurrent application of beta-receptor antagonist propranolol. However, delayed application of propranolol after the ICa enhancement did not affect Iso-induced potentiation, suggesting that the sustained effect was not caused by a slow washout of Iso. Nimodipine and omega-conotoxin-GVIA reduced the ICa by approximately 35 and approximately 29%, respectively, without reducing enhancement of ICa by Iso significantly. The modulation appeared to involve P-type current, because the enhancement was abolished after pretreatment with omega-agatoxin-IVA. Forskolin, an adenylyl cyclase activator, mimicked the action of Iso in enhancing ICa, and this effect was blocked by an inhibitor of cAMP cascade, indicating a cAMP-dependent mechanism. Iso also induced a long-term potentiation (LTP) of synaptic transmission, which could be prevented by P-type Ca2+ channel blockers. These results suggest that P-type Ca2+ channels were selectively upregulated in the basolateral amygdala neurons, and enhancement of P-type currents could contribute to presynaptic form of LTP.

Adrenergic beta-Agonists↗
PubMed1998

Inhibition of Na+, K+-ATPase activates swelling-induced taurine efflux in a human neuroblastoma cell line.

The Na+ pump (Na+, K+-ATPase) has been implicated in the regulation of many cellular functions, including cell volume regulation. The effects of inhibiting Na+ pump activity on cell volume and taurine efflux were evaluated in the human neuroblastoma cell line CHP-100. Cell volume changes monitored with the Coulter Multisizer technique and confocal microscopy showed that neuroblastoma cells exposed to ouabain swelled by 22 +/- 4% (n = 5). The rapid cell swelling was followed by regulatory volume decrease (RVD). In cells treated with ouabain, 14C-taurine efflux increased by 183 +/- 11% compared with controls. However, cells exposed simultaneously to ouabain and hypoosmotic solution resulted in a 14C-taurine efflux of 207 +/- 18%. Western blot and immunofluorescence microscopy with specific monoclonal antibodies for the catalytic alpha isoforms of Na+, K+-ATPase demonstrated high levels of the ubiquitously expressed alpha1 and the neuronal-specific alpha3. Ouabain-binding data showed that CHP-100 cells express approximately 3 x 10(5) pump units/cell. The present data indicate that efflux of taurine may be involved during volume recovery subsequent to blockade of Na+, K+-ATPase in CHP-100 cells.

Biological Transport↗
PubMed1998

High-level expression of rat farnesyl:protein transferase in Escherichia coli as a translationally coupled heterodimer.

Farnesyl:protein transferase (FPTase) catalyzes the transfer of a 15-carbon farnesyl isoprenoid group from farnesyl diphosphate to the CaaX cysteine of a variety of cellular proteins. Since FPTase is a large (95-kDa) heterodimeric protein and is inactive unless the alpha- and beta-subunits are coexpressed, large-scale overexpression of active enzyme has been challenging. We report the design of a translationally coupled expression system that will produce FPTase at levels as high as 30 mg/L Escherichia coli. Heterodimeric expression of FPTase was achieved using a translationally coupled operon from the T7 promoter of the pET23a (Novagen) expression plasmid. The beta-subunit-coding sequence was placed upstream of the alpha-subunit coding sequence linked by overlapping beta-subunit stop and alpha-subunit start codons. Additionally, the initial 88 codons of the alpha-subunit gene were altered, removing rare codons and replacing them with codons used in highly expressed proteins in E. coli. Since previous attempts at recombinantly expressing FPTase in E. coli from a translationally coupled system have demonstrated that initiation of translation of the alpha-subunit is poor, we propose that the optimization of the codons at the start of the alpha-subunit gene leads to the observed high level of recombinant expression.

Alkyl and Aryl Transferases↗