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Biomedical subjects

C C Huang

Publications and source records attributed to C C Huang.

At least 73 records · Page 4Linked to original sources
PubMed2001

Working memory of school-aged children with a history of febrile convulsions: a population study.

OBJECTIVE: A prospective, population-based, case-control study was performed to ascertain whether febrile convulsion (FC) in early childhood is associated with specific working memory characteristics in school age. METHODS: From a population survey of 4,340 live-birth newborns in Tainan City, Taiwan, 103 children with confirmed FC by age 3 years were followed-up until they were at least 6 years old. Three analogous searching tasks dissociating the mnemonic and executive aspects of performances were administered to 87 of these school-aged children and to 87 randomly selected age-matched control subjects to assess the learning, spatial, and sequential working memory. RESULTS: The FC group performed significantly and consistently better than control subjects on all but one working memory measure, jumping errors. Multivariate analysis using linear regression revealed that the onset of FC before age 1 year was the only significant risk factor for deficits in mnemonic function. Prior neurodevelopmental delay was the only significant risk factor for deficits in executive function. Factors such as socioeconomic status, family predisposition for seizures, complex FC, recurrent FC, and subsequent unprovoked seizures were not risk factors for working memory deficits. CONCLUSION: The authors found that school-aged children with a history of FC demonstrated significantly better mnemonic capacity, more flexible mental processing, and higher impulsivity than their age-matched control subjects. The underlying mechanism for the facilitated working memory function in children with a history of FC needs further delineation.

Child↗
PubMed2001

[Efficacy of prostaglandin E1 in the treatment of chronic pulmonary heart disease in the elderly people at the acute stage].

OBJECTIVE: To investigate the effects of prostaglandin E1 (PGE1) in the treatment of chronic pulmonary heart disease in the elderlys at the acute stage. METHODS: Forty cases of chronic pulmonary heart disease at the acute stage were treated with PGE1 at the dosage of 100 micrograms.d-1 for 7 days by intravenous drop, other 40 patients with the same disease were treated without PGE1, and 20 healthy subjects were selected as controls. The level of plasma D-dimer and serum fibrin degradation products (FDP), and blood PaO2 and PaCO2 were determined. The patients' symptoms and signs were observed before and after the treatment. RESULTS: The levels of plasma D-dimer and serum FDP were significantly increased (P < 0.01) in both the PGE1 group and the control group (no PGE1) compared to the healthy subjects. In PGE1 and no PGE1 groups the levels of plasma D-dimer and serum FDP were significantly decreased (P < 0.01) after the treatment. The level of PaO2 was increased and there was no significant difference (P > 0.05) between the two groups, but the level of PaCO2 was significantly decreased (P < 0.01) in both PGE1 and no PGE1 groups, but the decreasing in the PGE1 group was lower than that in the no PGE1 group. The symptoms and signs in PGE1 group were more markedly improved than those in the no PGE1 group. CONCLUSIONS: PGE1 is effective in the treatment of chronic pulmonary heart disease in old people at the acute stage.

Aged↗
PubMed2001

Time-dependent reversal of long-term potentiation by low-frequency stimulation at the hippocampal mossy fiber-CA3 synapses.

Using mouse hippocampal slices, we studied the induction of depotentiation of long-term potentiation (LTP) at the mossy fiber synapses onto CA3 pyramidal neurons. A long train of low-frequency (1 Hz/900 pulses) stimulation (LFS) induced a long-term depression of baseline synaptic transmission or depotentiation of previously established LTP, which was reversible and was independent of NMDA receptor activation. This LFS-induced depotentiation was observed when the stimulus was delivered 1 or 10 min after LTP induction. However, when LFS was applied at 30 min after induction, significantly less depotentiation was found. The induction of depotentiation on one input was associated with a heterosynaptic reverse of the LTP induced previously on a separate pathway. In addition, this LFS-induced depotentiation appeared to be mediated by the activation of group 2 metabotropic glutamate receptors (mGluRs), because it was mimicked by the bath-applied group 2 agonist (2S,2'R,3'R)-2-(2', 3'-dicarboxycyclopropyl) glycine and was specifically inhibited by the group 2 antagonists (S)-alpha-methyl-4-carboxyphenylglycine and (alphaS)-alpha-amino-alpha-(1S,2S)-2-carboxycyclopropyl-9H-xanthine-9-propanic acid. Moreover, the induction of depotentiation was entirely normal when synaptic transmission is blocked by glutamate receptor antagonist kynurenic acid and was associated with a reversal of paired-pulse facilitation attenuation during LTP expression. Pretreatment of the hippocampal slices with G(i/o)-protein inhibitor pertussis toxin (PTX) prevented the LFS-induced depotentiation. These results suggest that the activation of presynaptic group 2 mGluRs and in turn triggering a PTX-sensitive G(i/o)-protein-coupled signaling cascade may contribute to the LFS-induced depotentiation at the mossy fiber-CA3 synapses.

Animals↗
PubMed2001

Optical studies of the smectic-C(*)(alpha) phase layer structure in free-standing films.

The layer structure of the smectic-C(*)(alpha) phase of one liquid-crystal compound has been acquired from both differential optical reflectivity and ellipsometry measurements in the free-standing film geometry. The data from both techniques display characteristic oscillations as a function of temperature, which can be described by a model for the film consisting of surface anticlinic layers and an interior short-pitched azimuthal helix. These results are consistent with those found previously for another compound. Depolarized reflected light microscopy is used to study the films when the unique features of the aforementioned oscillations occur.

Journal Article↗
PubMed2001

Presynaptic mechanisms underlying cannabinoid inhibition of excitatory synaptic transmission in rat striatal neurons.

The striatum is a crucial site of action for the motor effects of cannabinoids (CBs). However, the electrophysiological consequences of activation of CB receptors on the striatal neurons have not been established. Here we report for the first time that the cannabimimetic aminoalkylindole WIN 55,212-2 and the endogenous cannabinoid anandamide substantially depress corticostriatal glutamatergic synaptic transmission onto striatal neurons in the brain slice preparation. The selective CB1 receptor antagonist SR 141716 effectively reversed this inhibition. WIN 55,212-2 significantly increased the paired-pulse facilitation of synaptically evoked EPSCs, while having no effect on the sensitivity of postsynaptic neurons to [alpha]-amino-3-hydroxy-5-methylisoxazole-4-propionic acid. WIN 55,212-2 also reduced the frequency of spontaneous, action potential-dependent EPSCs (sEPSCs) without altering their amplitude distribution. Superfusion of WIN 55,212-2 elicited a membrane hyperpolarization accompanied by a decrease in input resistance. Both effects were blocked by intracellular caesium. In contrast, intracellular caesium failed to affect WIN 55,212-2-mediated synaptic inhibition. The WIN 55,212-2-mediated synaptic inhibition was blocked by the Gi/o protein inhibitor pertussis toxin (PTX), but not by the GABA(A) receptor antagonist bicuculline or GABA(B) receptor antagonist SCH 50911. Pretreatment with the N-type Ca2+ channel antagonist [omega]-conotoxin GVIA selectively abolished the WIN-55,212-2-mediated synaptic inhibition. These results suggest that cannabinoids depress the corticostriatal glutamatergic synaptic transmission through the activation of presynaptic CB1 receptors to inhibit N-type Ca2+ channel activity, which in turn reduces glutamate release. The presynaptic action of cannabinoids is mediated by a PTX-sensitive Gi/o protein-coupled signalling pathway.

Action Potentials↗
PubMed2001

Unusual thickness-dependent thermal behavior and anticlinic coupling in chiral smectic free-standing liquid-crystal films.

We observe, in free-standing films of a chiral smectic liquid crystal, a series of discrete transitions in the relative orientation of the tilt of the interior and surface layers. These transitions include a remarkable reentrant synclinic-anticlinic-synclinic ordering sequence of the film surfaces in the presence of an electric field upon cooling. The profiles of the associated heat-capacity anomalies are found to be strongly thickness dependent and exhibit a novel crossover behavior in reduced dimensions. We measure the anticlinic coupling between tilted surface layers in the smectic- A phase.

Journal Article↗
PubMed2001

Optical studies of the liquid crystal B2 phase formed by banana-shaped molecules.

Null-transmission ellipsometry and depolarized light microscopy have been performed on free-standing films of three achiral banana-shaped compounds in the B2 phase. Our results support a two-layer unit cell previously proposed to explain the observed antiferroelectricity in thin films and bulk samples. We have studied thicker films than previously reported and have found no deviations in the film structure from the earlier findings. Moreover, we can determine the layer spacing, the molecular tilt from the layer normal, and the three principal indices of refraction in the molecular reference frame.

Journal Article↗
PubMed2001

Domain specific monoclonal anti-factor VIII antibodies generated by inclusion body-renatured factor VIII peptides.

Production of monoclonal anti-factor VIII (FVIII) antibodies was hampered by the availability of FVIII proteins devoid of albumin and the von Willebrand factor (vWF). We showed a successful way to generate domain specific anti-FVIII antibodies by using a series of Escherichia coli expressed FVIII fusion peptides. A total of eight fusion peptides were synthesized to cover almost the entire coding region of FVIII. All except one of the fusion peptides were insoluble and became aggregated as inclusion bodies. Purification and refolding of the peptides were accomplished by solublizing them with denaturants and dialyzing them in appropriate buffers, this being followed by chromatography of the refolded fractions on a metal-ion chelating column. These purified FVIII fusion peptides were used individually or as a pool to immunize mice and generate antibodies. Three monoclonal antibodies, D2, E6 and B12, were obtained. D2 recognizes a region (residues 1680-1703) of the light chain of FVIII, E6 recognizes a fragment (residues 744-1021) in the heavy chain, and B12, the A1 domain (residues 89-326). Both D2 and B12 inhibited >80% FVIII function. The affinities (k(A)) of the antibodies for FVIII were 1.62x10(7) M(-1) for D2 and 2.2x10(8) M(-1) for E6. Although B12 is inhibitory, it did not show a strong binding affinity with FVIII. The specificity of D2 and E6 for FVIII was demonstrated by immunoprecipitation of the FVIII protein in full-length recombinant FVIII (rFVIII) supplemented FVIII-deficient plasma, but not in FVIII-deficient plasma alone. An enzyme-linked immunosorbant assay (ELISA) using D2 or E6 was designed to detect plasma FVIII. The system may be useful in monitoring FVIII in cultured supernatants and in mouse models for gene therapy experiments.

Animals↗
PubMed2001

Computed free energy differences between point mutations in a collagen-like peptide.

We studied the results of mutating alanine --> glycine at three positions of a collagen-like peptide in an effort to develop a computational method for predicting the energetic and structural effects of a single point genetic mutation in collagen, which is associated with the clinical diagnosis of Osteogenesis Imperfecta (OI). The differences in free energy of denaturation were calculated between the collagen-like peptides [(POG)(4)(POA)(POG)(4)](3) and [(POG)(10)](3) (POG: proline-hydroxyproline-glycine).* Our computational results, which suggest significant destabilization of the collagen-like triple-helix upon the glycine --> alanine mutations, correlate very well with the experimental free energies of denaturation. The robustness of our collagen-like peptide model is shown by its reproduction of experimental results with both different simulation paths and different lengths of the model peptide. The individual free energy for each alanine --> glycine mutation (and the reverse free energy, glycine --> alanine mutation) in the collagen-like peptide has been calculated. We find that the first alanine introduced into the triple helix causes a very large destabilization of the helix, but the last alanine introduced into the same position of an adjacent chain causes a very small change in the peptide stability. Thus, our results demonstrate that each mutation does not contribute equally to the free energy. We find that the sum of the calculated individual residues' free energy can accurately model the experimental free energy for the whole peptide.

Carrier Proteins↗
PubMed2001

Outcome after treatment for papillary thyroid cancer.

BACKGROUND: To evaluate the results of treatment and the prognostic variables of papillary thyroid carcinoma patients after long-term follow-up. PATIENTS AND METHODS: Retrospective review of 1,373 thyroid cancer patients. Of the 1,016 papillary thyroid cancer patients, 394 patients received follow-up for more than 5 years, including 305 women (mean age, 38.4 +/- 13.7 years) and 89 men (mean age, 44.0 +/- 13.4 years). Of these papillary thyroid carcinoma patients, 227, 76, 68, and 23 patients were categorized in clinical stages I, II, III, and IV, respectively, at the time of diagnosis. RESULTS: After treatment, 36 (9.1%) patients died. Only 23 (5.8%) of them died of papillary thyroid carcinoma. The 1-, 5-, 10-, and 20-year survival rates were 0.980, 0.951, 0.901, and 0.731. Mortality factors of the papillary thyroid carcinoma patients related to age, gender, tumor size, and postoperative serum thyroglobulin (Tg) levels. Twenty-four patients progressed from clinical stages I, II, and III to stage IV during the follow-up period. Of these 24 patients, 12 died during the follow-up period. In this study, age, gender, 131I accumulated dose, postoperative serum Tg levels, and the survival rate were demonstrated to be statistically significant between the patients in early stage and advanced stage groups after treatment. CONCLUSION: Twenty-four of the 47 papillary thyroid cancer patients with distant metastases were diagnosed during the follow-up period. This study suggests that distant metastasis may occur at a serum Tg level of 2.3 ng/mL with thyroxine replacement. Postoperative long-term close follow-up of these patients is recommended.

Adult↗
PubMed2001

Maximization of injection volumes for DNA analysis in capillary electrophoresis.

We report concentration and separation of DNA in the presence of electroosmotic flow (EOF) using poly(ethylene oxide) (PEO) solution. DNA fragments migrating against EOF stacked between the sample zone and PEO solution. To maximize the injection volume, several factors, such as concentrations of Tris-borate (TB) buffer and PEO solution, capillary size, and matrix, were carefully evaluated. The use of 25 mM TB buffers, pH 10.0, containing suitable amounts (less than 10 mM) of salts, such as sodium chloride, sodium phosphate, and sodium acetate, to prepare DNA is essential for the concentration of large-volume samples. In the presence of salts, the peaks also became sharper and the fluorescence intensity of DNA complexes increased. Using 2.5% PEO and a 150 microm capillary filled with 400 mM TB buffer, pH 10.0, up to 5 microL DNA samples (phiX 174 RF DNA-HaeIII digest or the mixture of pBR 322/HaeIII, pBR 328/Bg/I, and pBR 328/HinfI digests) have been analyzed, resulting in more than 400-fold improvements in the sensitivity compared to that by conventional injections (ca. 36 nL). Moreover, this method allows the analysis of 3.5 microL PCR products amplified after 17 cycles without any sample pretreatment.

Buffers↗
PubMed2001

Effects of calcium, calmodulin, protein kinase C and protein tyrosine kinases on volume-activated taurine efflux in human erythroleukemia cells.

The effects of calcium, calmodulin, protein kinase C (PKC) and protein tyrosine kinase (PTK) modulators were examined on the volume-activated taurine efflux in the erythroleukemia cell line K562. Exposure to hypoosmotic solution significantly increased taurine efflux and intracellular calcium concentration ([Ca2+]i). The Ca2+ channel blockers La3+ (1 mM), verapamil (200 microM) and nifedipine (100 microM) inhibited the hypoosmotically-induced [Ca2+]i increase by more than 90%, while the volume-activated taurine efflux was inhibited by 61.3 +/- 9.5, 74.1 +/- 9.3 and 38.0 +/- 1.5%, respectively. Furthermore, the calmodulin inhibitors W7 (50 microM) and trifluoperazine (10 microM) and the Ca2+/calmodulin-dependent protein kinase II inhibitor KN-62 (2 microM) significantly blocked the volume-activated taurine efflux by 93.4 +/- 2.7, 77.9 +/- 3.5 and 61.3 +/- 15.8%, respectively. In contrast, the PKC inhibitor staurosporine (200 nM) or the PKC activator phorbol 12-myristate 13-acetate (100 nM) did not have significant effects on the volume-activated taurine efflux. However, pretreatment with PTK inhibitors genistein, tyrphostin A25, and tyrphostin A47 blocked the volume-activated taurine efflux. These results suggest that the volume-activated taurine efflux in K562 cells may not directly involve Ca2+, but may require the presence of calmodulin and/or PTK.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2001

High-resolution cranial ultrasound in the shaken-baby syndrome.

With limited near-field resolution and accessible acoustic windows, sonography has not been advocated for assessing central nervous system injuries in the shaken-baby syndrome. Our purpose was to correlate high-resolution ultrasonographic characteristics of central nervous system injuries in whiplash injuries and the shaken-baby-syndrome with MRI and CT. Ultrasonographic images of 13 infants, aged 2-12 months, with whiplash or shaking cranial trauma were reviewed and compared with MRI in 10 and CT in 10. Five patients had serial ultrasonography and MRI or CT follow-up from 1 to 4 months after the initial injury. With ultrasonography we identified 20 subdural haematomas. MRI and CT in 15 of these showed that four were hyperechoic in the acute stage, three were mildly echogenic in the subacute stage, and that one subacute and seven chronic lesions were echo-free. Five patients had acute focal or diffuse echogenic cortical oedema which evolved into subacute subcortical hyperechoic haemorrhage in four, and well-defined chronic sonolucent cystic or noncystic encephalomalacia was seen at follow-up in two. Using ultrasonography we were unable to detect two posterior cranial fossa subdural haematomas or subarachnoid haemorrhage in the basal cisterns in three cases, but did show blood in the interhemispheric cistern and convexity sulci in two. U1-trasonography has limitations in demonstrating abnormalities remote from the high cerebral convexities but may be a useful adjunct to CT and MRI in monitoring the progression of central nervous system injuries in infants receiving intensive care.

Battered Child Syndrome↗
PubMed2001

Differences in 99mTc-HMPAO brain SPET perfusion imaging between Tourette's syndrome and chronic tic disorder in children.

Early differential diagnosis between Tourette's syndrome and chronic tic disorder is difficult but important because both the outcome and the treatment of these two childhood-onset diseases are distinct. We assessed the sensitivity and specificity of brain single-photon emission tomography (SPET) perfusion imaging in distinguishing the two diseases, and characterized their different cerebral perfusion patterns. Twenty-seven children with Tourette's syndrome and 11 with chronic tic disorder (mean age 9.5 and 8.6 years, respectively) underwent brain SPET with technetium-99m hexamethylpropylene amine oxime (HMPAO). Visual interpretation and semiquantitative analysis of SPET images were performed. On visual interpretation, 22 of 27 (82%) of the Tourette's syndrome group had lesions characterized by decreased perfusion. The left hemisphere was more frequently involved. None of the children with chronic tic disorder had a visible abnormality. Semi-quantitative analysis showed that, compared with children with chronic tic disorder, children with Tourette's syndrome had significantly lower perfusion in the left lateral temporal area and asymmetric perfusion in the dorsolateral frontal, lateral and medial temporal areas. In conclusion, using the visual approach, brain SPET perfusion imaging is sensitive and specific in differentiating Tourette's syndrome and chronic tic disorder. The perfusion difference between the two groups, demonstrated by semi-quantitative analysis, may be related more to the co-morbidity in Tourette's syndrome than to tics per se.

Adolescent↗
PubMed2001

Congenital prepubic sinus: a variant of dorsal urethral duplication suggested by immunohistochemical analysis.

PURPOSE: Congenital prepubic sinus is a rare disorder of uncertain etiology. Immunohistochemical staining is used to elucidate the etiology of the sinus. MATERIALS AND METHODS: We treated 5 patients with congenital prepubic sinus. A sinogram delineated the tract, which was then excised. In addition to routine hematoxylin and eosin stain of the 5 specimens, immunohistochemical analysis was also performed with smooth muscle and sarcomeric actin, high (34betaE12) and low molecular weight cytokeratin (35betaH11), and cytokeratin 7 antibodies. RESULTS: The 2 females and 3 males were 1 month to 14 years old. All patients had presented with purulent discharge from the sinus opening. Hematoxylin and eosin stain demonstrated transitional and squamous epithelium lining the sinus. Immunohistochemical study showed that the stain with 3 cytokeratin antibodies was moderately to strongly positive in all patients at the proximal end, low molecular weight cytokeratin weakly to moderately positive and cytokeratin 7 weakly positive to negative in 4 at the distal end. The results suggested that the lining epithelium was transitional proximally and squamous distally. An exception was a female patient who had the shortest tract lined with squamous epithelium only. Furthermore, smooth muscle but not sarcomeric actin demonstrated smooth muscle bundles around the sinus tract in 4 patients. CONCLUSIONS: The existence of transitional epithelium in the proximal part of the sinus and presence of smooth muscle bundles around it reinforce the theory that congenital prepubic sinus is a variant form of dorsal urethral duplication.

Adolescent↗
PubMed2001

Spontaneous rupture of hepatocellular carcinoma during pregnancy.

BACKGROUND: Hepatocellular carcinoma associated with pregnancy is unusual. CASE: A 33-year-old woman presented at 25 weeks' gestation with sudden, severe epigastric pain for 6 hours. Abdominal ultrasonography and magnetic resonance imaging showed multiple liver tumors with a small amount of ascites. Exploratory laparotomy revealed an unresectable ruptured liver tumor that was treated by packing. Although a biopsy was nondiagnostic, ultrasound-guided needle biopsy 6 days after cesarean delivery at 41 weeks' gestation showed hepatocellular carcinoma, which was treated with transarterial embolization. At 3.5 years posttherapy, both mother and infant are well. CONCLUSION: Ruptured hepatocellular carcinoma during pregnancy is rare but should be included in the differential diagnosis of sudden, severe epigastric pain.

Abdomen, Acute↗
PubMed2001

Trace metals in different species of mollusca, water and sediments from Taiwan coastal area.

Since October 1994, a long-term program of Asia/Pacific Mussel Watch: Taiwan Regional Studies has been carried out. The results indicate that trace metal contents in mollusca varied among 30 different species and the environments (water and sediments) along the Taiwan coast. The orders of bioaccumulation of trace metals in mollusca were: Cu (over 200 microg/g), Thais clavigera > Isognomon legumen > Clibanarius rivescens > Crassostrea gigas; Zn (over 700 microg/g), Moruta granulata > C. gigas > Asiatica cypraea arabica > T. clavigera; Cd (over 5 microg/g), Trochus hanleyanus > Acanthopleura japonica > Nerita albicilla > Patella flexuosa; Pb (over 2 microg/g), P. flexuosa > C. gigas > T. hanleyanus > T. clavigera > C. gigas > Capiyulum mitella; Ni (over 10 microg/g), Meretrix lusoria > Philine sp. > Littoraria scabra > Tridacna squamosa > T. hanleyanus; Cr (over 30 microg/g), Littoraria undulata > T. hanleyanus > N. albicilla > Nerita chamaelor > M. granulata; As (over 20 microg/g), Perna viridis > L. scabra; and Sn (over 5 microg/g), P. viridis > L. undulata> C. mitella> C. gigas. Their seasonal and regional variations as well as their correlation are evaluated and discussed.

Animals↗