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Biomedical subjects

H C Liu

Publications and source records attributed to H C Liu.

At least 109 records · Page 6Linked to original sources
PubMed1999

Detection of PAX3-FKHR and PAX7-FKHR fusion transcripts in rhabdomyosarcoma by reverse transcriptase-polymerase chain reaction using paraffin-embedded tissue.

BACKGROUND: Alveolar rhabdomyosarcoma (RMS) is associated with a characteristic chromosomal translocation t(2;13)(q35;q14). The genes involved in this translocation are paired box (PAX)3 on chromosome 2 and forkhead in RMS (FKHR) on chromosome 13. An occasional variant translocation t(1;13)(p36;q14) affecting PAX7 and FKHR on chromosomes 1 and 13, respectively, has also been described. Chromosomal translocations in RMS are detected using conventional cytogenetic analysis, fluorescence in situ hybridization (FISH) or reverse transcriptase-polymerase chain reaction (RT-PCR) on fresh or frozen tissue samples. We describe the results of RT-PCR analysis of PAX3-FKHR and PAX7-FKHR chimeric messages in formalin-fixed, paraffin-embedded tissue samples from 17 RMS cases. METHODS: RNA was extracted from formalin-fixed, paraffin-embedded RMS tissue. Oligonucleotide primers corresponding to the regions of PAX3, PAX7 and FKHR were used for the detection of PAX3-FKHR and PAX7-FKHR chimeric messages. A seminested PCR of the PCR products was used to increase the sensitivity of detection. The amplified fragments were purified and directly sequenced to confirm the specificity of the methods. RESULTS: The PAX3-FKHR chimeric message was detected in all three cases of alveolar RMS but not in any of the 12 embryonal and two pleomorphic RMS cases. The PAX7-FKHR fusion transcript was detected in one case of embryonal RMS. CONCLUSIONS: The results indicate that the RT-PCR assay is a reliable method for the detection of the PAX3-FKHR fusion transcript of alveolar RMS in formalin-fixed, paraffin-embedded tissue. This simple method enables pathologists to identify chromosomal rearrangements in RMS as a diagnostic aid in cases where fresh or frozen tissue is not available.

DNA-Binding Proteins↗
PubMed1999

Neonatal vallecular cyst: report of eleven cases.

BACKGROUND: Vallecular cyst is fairly uncommon in neonates and infants. Although benign in nature, it may cause severe airway obstruction and even death. This study retrospectively analyzed the clinical manifestations of vallecular cyst in neonates and discussed its management. METHODS: From June 1993 through January 1997, 11 cases of vallecular cyst were collected and reviewed retrospectively. There were 8 male infants and 3 female infants. Their clinical manifestations, age at the onset of symptoms, age at diagnosis, and surgical management were analyzed. Fibrolaryngoscopy was used for preoperative diagnosis and postoperative follow-up. RESULTS: The infants' initial presentations were inspiratory stridor, respiratory distress, noisy breathing, feeding difficulty, and failure to thrive. There was a high incidence of patients with coexisting signs of laryngomalacia (10/11). Ten patients received laryngomicrosurgery with CO2 laser for deroofing the cyst. Additional supraglottoplasty was performed at the same time in 4 patients with laryngomalacia type A + C and in one patient with severe laryngomalacia type C. Their symptoms all resolved soon after surgery. The phenomenon of laryngomalacia also disappeared. There has been no recurrence up to the present. CONCLUSION: Although fairly uncommon, vallecular cyst should be included in the differential diagnosis of congenital laryngeal stridor in neonates. The use of fibroendoscopy can promptly diagnose vallecular cyst and any synchronous airway lesions. Although most of the synchronous laryngomalacia (type C) in this study was secondary to vallecular cyst, we suggest that supraglottoplasty be taken into consideration during cyst deroofing when the signs and symptoms of laryngomalacia type A are also present.

Cysts↗
PubMed1999

Mandibular osteomyelitis caused by Blastoschizomyces capitatus in a child with acute myelogenous leukemia.

A 6-year-old girl with acute myelogenous leukemia (AML) developed fungal mandibular osteomyelitis during chemotherapy. Blastoschizomyces capitatus was recognized histologically by its yeast-like morphology and formation of annelloconidia, and was confirmed by culture. The fungal osteomyelitis of the mandible was treated successfully with prolonged antifungal medication, extensive surgical debridement and an oral care program, without interrupting leukemia chemotherapy. B. capitatus osteomyelitis of the mandible may occur during chemotherapy in AML patients with poor dental condition. Successful treatment can be achieved by careful management without interruption of antineoplastic chemotherapy.

Child↗
PubMed1999

[Determination of acemetacin and indometacin in human serum by high performance liquid chromatography].

A method of HPLC for the quantitative determination of acemetacin and indometacin in human serum is described. After being extracted with diethyl ether, acemetacin and indometacin were analyzed by reversed-phase HPLC(Spherisorb-C8) and UV-detector(254 nm), with tolbutamide as internal standard. The mobile phase was a mixture of V(acetate buffer solution, pH 4.6):V(methyl alcohol):V(acetonitrile) = 55:5:40 and at a rate of 1.0 mL/min. Over the mass concentration range of 12.5 micrograms/L-1.6 mg/L, both the calibration curves were linear, r = 0.9996, n = 8. The average recoveries of acemetacin and indometacin were 77.2% and 86.7% respectively. The within-day and between-day RSD of acemetacin and indometacin were less than 5% and 10% respectively.

Adult↗
PubMed1998

Transcriptional regulation of mouse mu-opioid receptor gene.

Previously, the existence of dual promoters was reported in mouse mu-opioid receptor (mor) gene, with mor transcription in the mouse brain predominantly initiated by the proximal promoter. In this study, we further analyzed the proximal promoter region, base pairs -450 to -249, to identify cis-DNA regulatory elements and trans-acting protein factors that are important for mor promoter activity. The results revealed that a mor inverted GA (iGA) motif and a canonical Sp1 binding site are required for the promoter activity. Using electrophoretic mobility shift analysis, we identified nuclear proteins that specifically bind to the mor iGA motif and that are immunologically related to Sp1 and Sp3. Mutation of the mor iGA motif, resulting in a loss of Sp binding, led to a 50% decrease in activity. Mutation of the canonical Sp1 binding site yielded a lesser (approximately 25%) loss of activity. Mutation of both motifs together resulted in an approximately 70% decrease in activity. In cotransfection assays using Drosophila SL2 cells, Sp1 trans-activated the promoter in a manner dependent on the presence of mor iGA and canonical Sp1 binding motifs. Sp3 can also trans-activate the promoter, and furthermore, Sp1 and Sp3 can trans-activate the mor promoter additively. Our results suggest that combined or cooperative interaction of Sp transcription factors within the proximal promoter is necessary for activation of mor gene transcription.

Animals↗
PubMed1998

Enantiomeric inhibitors of cholesterol esterase and acetylcholinesterase.

Enantiomers of N-methyl-N,alpha-methylbenzylbutyramide (1), 1-butyl-3-methyl-3'-alpha-methylbenzylurea (2), 1,2,3, 4-tetrahydro-1-naphthyl-N-butylcarbamate (3), 1,1'-bi-2-naphthyl-2, 2'-di-N-butylcarbamate (4), 1, 1'-bi-2-naphthyl-2-ol-2'-N-butylcarbamate (5), and 1, 1'-bi-2-naphthyl-2-butyrate-2'-N-butylcarbamate (6) are inhibitors of porcine pancreatic cholesterol esterase-catalyzed hydrolysis of 4-nitrophenyl butyrate and of electric eel acetylcholinesterase-catalyzed hydrolysis of acetylthiocholine in the presence of 5,5'-dithiobis-2-nitrobenzoate. For competitive inhibitors, values of the inhibition constant (Ki) and the enantiomeric ratio (Ecomp.) are investigated. For active site-directed irreversible inhibitors, values of the inhibition constant (Ki), the carbamylation constant (k2), the bimolecular rate constant (ki), and the enantiomeric ratio (E) are investigated. Toward both enzymes, compounds 1 are poor competitive inhibitors (Ki=102-104 microM) but have good enantioselectivities (Ecomp.=10-50, the preference for R). R-2 and S-2 are competitive inhibitors of acetylcholinesterase with Ki=26 and 80 microM, respectively (the preference for R) but are active site-directed irreversible inhibitors of cholesterol esterase with ki=4 and 16 M-1 sec-1, respectively (the preference for S). For those competitive inhibitions, both leaving group hydrophilic and hydrophobic binding sites of cholesterol esterase or both anionic substrate binding site and peripheral anionic binding site of acetylcholinesterase bind to N,N-methyl-alpha-methylbenzyl disubstituted amide parts of these inhibitors and the enzyme does not catalyze the hydrolysis of these inhibitors. The opposite stereopreference (S) for the inhibition of cholesterol esterase by compounds 2 may be due to the fact that N, N-methyl-alpha-methylbenzyl disubstituted amide parts of these inhibitors bind to the alkyl chain binding site of the enzyme. Compounds 3-6 are active site-directed irreversible inhibitors of cholesterol esterase (ki=1-13000 M-1 s-1) and peripheral anionic binding site-directed irreversible inhibitors of acetylcholinesterase (ki=1.7-1300 M-1 s-1). Compounds 3 have low enantioselectivities (E=1.3-1.4) for both enzymes. The stereopreference for atropisomers 4 and 6 is S-form toward both enzymes (E=2-30) and is identical to that of cholesterol esterase-catalyzed hydrolysis of 1,1'-bi-2-naphthyl-2,2'-diacylate. This stereopreference (S) may be due to the fact that the butyryl group or one of two butylcarbamate groups of S-atropisomers binds more effectively to the leaving group hydrophobic binding site of cholesterol esterase or the peripheral anionic binding site of acetylcholinesterase than that of R-atropisomers. The opposite stereopreference (R) for atropisomers 5 toward both enzymes may be due to a favorable interaction between the hydroxyl group of the inhibitors and the leaving group hydrophilic binding site of cholesterol esterase or the peripheral anionic binding site of acetylcholinesterase.

Acetylcholinesterase↗
PubMed1998

Evolution of the avian sex chromosomes from an ancestral pair of autosomes.

Among the mechanisms whereby sex is determined in animals, chromosomal sex determination is found in a wide variety of distant taxa. The widespread but not ubiquitous occurrence, not even within lineages, of chromosomal sex determination suggests that sex chromosomes have evolved independently several times during animal radiation, but firm evidence for this is lacking. The most favored model for this process is gradual differentiation of ancestral pairs of autosomes. As known for mammals, sex chromosomes may have a very ancient origin, and it has even been speculated that the sex chromosomes of mammals and birds would share a common chromosomal ancestry. In this study we showed that the two genes, ATP5A1 and CHD1, so far assigned to the female-specific W chromosome of birds both exist in a very closely related copy on the Z chromosome but are not pseudoautosomal. This indicates a common ancestry of the two sex chromosomes, consistent with the evolution from a pair of autosomes. Comparative mapping demonstrates, however, that ATP5A1 and CHD1 are not sex-linked among eutherian mammals; this is also not the case for the majority of other genes so far assigned to the avian Z chromosome. Our results suggest that the evolution of sex chromosomes has occurred independently in mammals and birds.

Animals↗
PubMed1998

Association of apolipoprotein E genotype and intronic polymorphism of the presenilin-1 gene with Alzheimer's disease in elderly Taiwan Chinese.

We studied the apoliprotein E (apo-E) allele frequencies and intronic polymorphism of the presenilin-1 (PS-1) gene in 55 patients with late-onset Alzheimer's disease (AD) and 93 age- and sex-matched controls. The apoE epsilon4 allele frequency was significantly higher in the AD group than in the control group (0.255 versus 0.070, P<0.0001). The odds ratio for AD in individuals with either one or two epsilon4 alleles was 5.22 (95% confidence interval: 2.32-11.70). The polymorphism within the region composing intron 3' to exon 8 of the PS-1 gene showed a similar distribution between AD patients and controls. This is the first study on the intronic polymorphism of the PS-1 gene in Chinese. Our results support an association between apoE epislon4 and AD in Chinese, but not between the intronic polymorphism of the PS-1 gene and AD. However, the allele frequency of apo-E epsilon4 among Chinese is lower than that among Caucasians. The interaction between apo-E and PS-1 genotypes is still unclear.

Aged↗
PubMed1998

Influence of hydroxyapatite particle size on bone cell activities: an in vitro study.

Over the past decade, a large number of biomaterials have been proposed as artificial bone fillers for repairing bone defects. The material most widely used in clinical medicine is hydroxyapatite. The aim of our investigation was to study the effect of hydroxyapatite size mechanism on osteoblasts. The osteoblasts were cultured in vitro with 0.1% (1 mg/mL) of various sized hydroxyapatite particles (0.5-3.0, 37-63, 177-250, and 420-841 microm) for 1 h, 3 h, 1 day, 3 days, and 7 days. The results showed that adding hydroxyapatite particles to osteoblast cultures can significantly affect osteoblast cell count. Osteoblast populations decreased significantly. Osteoblast mean surface areas also changed significantly. Transforming growth factor-beta1 (TGF-beta1) concentrations in culture medium decreased significantly with the addition of hydroxyapatite particles. Prostaglandin E2 (PGE2) concentrations in medium increased significantly. The changes in TGF-beta1 and PGE2 concentration were more significant and persisted longer in smaller-particle groups. The inhibitory effects of hydroxyapatite particles on osteoblast cell cultures were mediated by the increased synthesis of PGE2. Caution should be exercised before using a hydroxyapatite product which could easily break down into fine particles.

Alkaline Phosphatase↗
PubMed1998

mu Opioid receptor knockout in mice: effects on ligand-induced analgesia and morphine lethality.

The mu opioid receptor gene (MOR) was mutated in mice by a gene targeting procedure. In these MOR-knockout mice, the analgesic effects of morphine, its major metabolites, morphine-6-glucuronide (M-6-G) and morphine-6-ethereal sulfate (M-6-S), and endomorphin-2, as well as morphine-induced lethality, were drastically reduced, whereas the effects of DPDPE and U50488 remained unchanged. It is concluded that analgesic effects of mu-specific opioid ligands and acute morphine lethality are mediated by the mu receptor.

Analgesics, Opioid↗
PubMed1998

High-dose cytarabine-containing chemotherapy with or without granulocyte colony-stimulating factor for children with acute leukemia.

We sought to determine the role of granulocyte colony-stimulating factor (G-CSF) as an adjunct therapy in high-dose cytarabine-containing chemotherapy (HD C/T) for children with acute leukemia. Seventeen patients, aged 9 months to 18 years old, 8 ALL and 9 AML, were treated with cytarabine (Ara-C) 1 g/m2 q12h for 8 doses with mitoxantrone, idarubicin, VP-16, or asparaginase. A total of 71 courses of HD C/T was given. G-CSF was not used in 14 courses (Group A). Prophylactic G-CSF was given in 57 courses (Group B) as 200 microg/m2/d SC started one day after the completion of HD C/T and continued until the neutrophil recovery was maintained. The incidences of sepsis per course in Group A and Group B were 35.7% (5/14) and 40.4% (23/57), respectively. While 2 patients in Group A died of sepsis or pneumonia, none in Group B died. The mortality and delay in chemotherapy were fewer in Group B (P = 0.037 and 0.0006, respectively, Fisher exact test). There was a shorter average number of days of neutrophil <500/cumm, antibiotic usage, fever, and hospital stay in Group B (11, 8, 5, 17 days in Group B vs. 21, 17, 10, 37 days in Group A; P = 0.0001, log-rank test; 0.0006, 0.0023, 0.0001, Wilcoxon rank sum test, respectively). The incidence of neutropenic fever was lower in Group B, but the difference did not reach statistical significance (P = 0.06, Fisher exact test). We conclude that G-CSF as an adjunct therapy in HD C/T is effective in reducing mortality, days of neutropenia, antibiotic usage, fever, hospital stay, and frequency of delay in chemotherapy. The efficacy of this treatment approach requires further testing in a randomized, controlled trial.

Acute Disease↗
PubMed1998

Characteristics of consecutive in vitro fertilization cycles among patients treated with follicle-stimulating hormone (FSH) and human menopausal gonadotropin versus FSH alone.

OBJECTIVE: To compare the endocrine responses of patients who first received hMG plus FSH, then were treated in a subsequent cycle with FSH alone. DESIGN: Retrospective study. SETTING: An academic research environment. PATIENT(S): Ninety-six women with pituitary down-regulation who underwent two sequential IVF treatments, the first with combined hMG and FSH and the second with FSH alone. MAIN OUTCOME MEASURE(S): Duration of stimulation, serum estradiol level on the day of hCG administration, amount of gonadotropin used, number of oocytes retrieved, number of oocytes fertilized, and selected preembryo morphologic features. RESULT(S): No difference in the mean duration of stimulation was observed between the treatment cycles among patients who received hMG and FSH (11.9 days) followed by FSH alone (11.7 days). The mean number of oocytes retrieved, the mean number of oocytes fertilized, the percentage of preembryo fragmentation, and the preembryo cell number at transfer did not differ significantly between the stimulation protocols. The cumulative amount of gonadotropin used during stimulation was slightly greater in the cycles stimulated with FSH alone, but this difference was not significant (29.4 ampules of hMG plus FSH versus 31.8 ampules of FSH alone). Serum estradiol levels measured on the day of hCG administration during stimulation with hMG and FSH (1,382 pg/mL) were higher than those measured during stimulation with FSH alone (1,149 pg/mL). CONCLUSION(S): Follicular response and preembryo quality were not significantly different when patients were treated first with hMG and FSH and then with FSH alone in a subsequent cycle. Similarities in ovarian response and preembryo characteristics, as well as differences in estradiol patterns seen in each stimulation setting, should be anticipated when patients receive these protocols.

Adult↗
PubMed1998

Human preembryo development on autologous endometrial coculture versus conventional medium.

OBJECTIVE: To evaluate the effect of autologous endometrial coculture versus conventional medium on preembryo development. DESIGN: Controlled systematic clinical study. SETTING: University-based IVF center. PATIENT(S): Women with a history of failed IVF-ET with poor preembryo quality. INTERVENTION(S): Patients underwent a luteal phase endometrial biopsy. The tissue then was digested enzymatically, and the stromal and glandular cells were separated by differential sedimentation rates. These cells were cultured to confluence, released, and then cryopreserved until the patient's IVF-ET cycle. All normally fertilized oocytes then were allocated systematically to growth on autologous endometrial coculture or conventional medium until transfer on day 3. MAIN OUTCOME MEASURE(S): Preembryo blastomere numbers and cytoplasmic fragmentation rates were measured. RESULT(S): Forty-two women underwent 44 cycles of IVF-ET. In the morning on day 3, the mean (+/-SD) number of blastomeres and cytoplasmic fragments per preembryo on coculture compared with conventional medium was 5.9+/-1.5 versus 5.5+/-1.4 and 21%+/-13% versus 24%+/-11. At transfer the mean (+/-SD) number of blastomeres per preembryo on coculture was 7.4+/-1.3 versus 6.7+/-1.9 on conventional medium. CONCLUSION(S): There was a significant improvement in the mean (+/-SD) number of blastomeres per preembryo and decrease in the fragmentation rate for preembryos on autologous endometrial coculture compared with noncocultured preembryos from the same patient.

Adult↗
PubMed1998

Prevalence and distribution of cervical dentin hypersensitivity in a population in Taipei, Taiwan.

The prevalence, distribution, and possible causal factors of cervical dentin hypersensitivity were studied in a population attending the Health Examination Center of National Taiwan University Hospital. A total of 780 patients were examined for the presence of cervical dentin hypersensitivity by means of a questionnaire and intraoral tests. There were 253 patients (32%) who claimed to have hypersensitive teeth at present and 90 patients (12%) who reported a history of hypersensitive teeth. The intraoral distribution of hypersensitivity showed that premolars and molars were the most common teeth sensitive to the air and probe stimuli, while the incisors were the least sensitive ones. The presence and history of dentin hypersensitivity were positively correlated with previous tooth-brushing and periodontal disease. Only a few of the patients who claimed to have dentin hypersensitivity had tried treatment with desensitizing tooth-pastes (11%) or sought professional help (5%).

Adult↗
PubMed1998

Biological effects and cytotoxicity of the composite composed by tricalcium phosphate and glutaraldehyde cross-linked gelatin.

The purpose of this study was to prepare and evaluate the feasibility and cytocompatibility of a composite (GTG) as a large defect bone substitute. The composite is combined with tricalcium phosphate ceramic particles and glutaraldehyde cross-linked gelatin. Gelatin had been reported as an adhesive and biocompatible binder that could accelerate the recovery of damaged soft tissue, but the effects of gelatin when acting on the bone tissue is not clear. Thus, it is necessary to determine if the substances released from the GTG composite can facilitate the growth of bone cells. The substances released from the GTG composites after being soaked in deionized distilled water were analyzed by gas chromatography (GC), ultraviolet and visible absorption spectroscopy (UV-VIS), and inductive-coupled plasma-atomic emission spectrometry (ICP-AES). The cytotoxicity of the GTG composites was assessed by coculture of rat osteoblasts in vitro. Extracts were obtained by soaking the GTG composites in deionized distilled water for 1, 2, 4, 7, 14, 28 and 42 d. The extract mixed with complete medium in a ratio of 1:1 was added into the cell culture wells containing 1 x 10(4) cells ml(-1) osteoblasts. After culturing for 2 days, the cells attached to the surface of wells were trypsinized and the number calculated by the Neubauer counting-chamber under the optical microscope. Finally, three samples in each GTG group were examined by scanning electron microscopy (SEM) to observe the morphology of the osteoblasts attached to the surfaces of GTG composites. The examinations of osteoblasts cocultured with the developed GTG composites were used to decide the ideal concentration of glutaraldehyde as a cross-linking agent. The results of extracts cocultured with osteoblasts showed that the extracts obtained from the 2, 4 and 8% glutaraldehyde cross-linked GTG composites would inhibit the growth of osteoblasts in the first 4 soaking days. During the 4-7 days soaking, the cell numbers quickly increased with the soaking time, thereafter, the cell numbers almost reached a constant value. In the analyses of substances released from the GTG composites, it was found that the gelatin and calcium were gradually released from the GTG composites, which were supposed to be nutritious for the growth of the osteoblast. The results of osteoblasts cocultured with the GTG composites showed that the concentration of glutaraldehyde used as a cross-linking agent should be lower than 8%. Compared to the GTF (composite combined with tricalcium phosphate ceramic particles and formaldehyde cross-linked gelatin), GTG composites were much suitable for a large defect bone substitute in the near future.

Animals↗
PubMed1998

mu-Opioid receptor-knockout mice: the role of mu-opioid receptor in gastrointestinal transit.

The role of mu-opioid receptor in gastrointestinal transit was investigated using mu-opioid receptor knockout mice (MOR-KO). Our result establishes unequivocally that inhibition of GI transit by morphine is a mu-opioid receptor mediated function. In addition, we show that neither delta nor kappa receptor agonist given supraspinally or peripherally are able to inhibit GI transit in MOR-KO animals. It was interesting to observe that basal GI motility was lower in MOR-KO (-/-) compared to heterozygous (+/-) and wild type (+/+) animals.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1998

Proton magnetic resonance spectroscopy in deep cerebral venous thrombosis.

A 63-year-old man developed a severe left frontal headache followed by an acute change of mentality 6 days later. Magnetic resonance imaging revealed bilateral thalamic ischemia. Angiography confirmed the occlusion of deep cerebral veins. Proton magnetic resonance spectroscopy (1H-MRS) of the thalami showed normal N-acetylaspartate (NAA) peak and the presence of lactate peak, indicating a relatively preserved neuronal viability. The patient improved during the follow-up period, and returned to work 45 days after the onset of the disease. With 1H-MRS, prognosis following venous infarctions may be feasible.

Humans↗