Biomedical subjects

C M Liu

Publications and source records attributed to C M Liu.

At least 19 recordsLinked to original sources

PubMed2001

Suggestive evidence for linkage of schizophrenia to markers at chromosome 15q13-14 in Taiwanese families.

In order to evaluate the linkage of schizophrenia to loci at chromosome 15q, we genotyped six microsatellite markers at chromosome 15q11-14 in 52 Taiwanese schizophrenic families. Two phenotype models (narrow: DSM-IV schizophrenia only; and broad: including schizophrenia, schizoaffective, and other nonaffective psychotic disorders) were used to define the disease phenotype. Maximum nonparametric linkage scores (NPL scores) of 3.33 (P = 0.0003) and 2.96 (P = 0.0008) were obtained at the marker D15S976 under broad and narrow models, respectively. Positive linkage results were also observed at the marker D15S1360, previously reported to have significant linkage to a neurophysiological deficit of schizophrenia, with NPL scores of 2.71 (P = 0.003) and 2.78 (P = 0.002) under broad and narrow models, respectively. The results provide suggestive linkage evidence of schizophrenia to loci at chromosome 15q13-14 in an ethnically distinct Taiwanese sample.

Chromosomes, Human, Pair 15↗

PubMed2001

Mechanisms involved in the inhibition of neointimal hyperplasia by abciximab in a rat model of balloon angioplasty.

Monoclonal antibodies raised against beta(3) integrin are able to inhibit the binding of ligands to certain beta(3) integrins such as alpha(IIb)beta(3) (glycoprotein IIb/IIIa complex) and alpha(v)beta(3) (vitronectin receptor) and as such are inhibitors of platelet aggregation and smooth muscle cell (SMC) migration, both of which are involved in neointimal hyperplasia. The present study was designed to explore the detailed mechanisms of abciximab (Reopro), a monoclonal antibody (mAb) raised against alpha(IIb)beta(3) integrin in neointimal hyperplasia. In this study, carotid arteries of Wistar rats were damaged, and neointimal hyperplasia and lumen occlusion was determined at different time points. Abciximab was administered intravenously by an implanted osmotic pump. Abciximab (0.25 mg/kg/day) time-dependently inhibited both neointimal hyperplasia and lumen occlusion after angioplasty in carotid arteries of rats. Furthermore, the electromicrographs highlighted that SMCs were phenotypically different from the typical contractile, spindle-shaped SMCs normally seen in uninjured vessel walls. Platelet-derived growth factor (PDGF)-BB was strongly produced in thrombus formation and neointimal SMCs after angioplasty, while abciximab significantly reduced PDGF-BB expression in vessel lumens and neointimal SMCs after angioplasty. Balloon angioplasty caused a significant increase of nitrate and cyclic GMP as compared with sham-operated rats. Infusion of abciximab (0.25 mg/kg/day) did not significantly change. Furthermore, the plasma level of thromboxane B(2) (TxB(2)) obviously increased after angioplasty, while abciximab markedly suppressed the elevation of plasma TxB(2) concentration. The results indicate that abciximab effectively prevents neointimal hyperplasia, possibly through the following 2 mechanisms: (1) Abciximab binds to alpha(IIb)beta(3) integrin on platelet membranes resulting in inhibition of platelet adhesion, secretion, and aggregation in injured arteries, followed by inhibition of thromboxane A(2) formation and PDGF-BB release from platelets. (2) Abciximab may also bind to alpha(v)beta(3) integrin on SMCs, thus, subsequently inhibiting cell migration and proliferation.

Abciximab↗

PubMed2001

Identification of a human brain-specific gene, calneuron 1, a new member of the calmodulin superfamily.

The calmodulin superfamily includes the calmodulins, calcium-binding proteins, and related genes. Herein, we describe the cloning and characterization of human calneuron 1 (CALN1). CALN1 encodes a novel neuron-specific protein that maps to chromosome 7q11. CALN1 spans a large genomic region (>360 kb). Sequence comparison shows significant similarity with the calmodulin superfamily of genes, especially in the two conserved EF-hand motifs. The mouse orthologous gene (Caln1) shows little prenatal expression, with highest expression at Postnatal Day 21. In situ hybridization to adult mouse brain shows high expression in the cerebellum, hippocampus, and cortex. The high expression of this gene exclusively in brain, the developmental changes in expression levels, the high homology with calmodulin which indicates a potential role in signal transduction, and the cellular localization of the mRNA suggest that CALN1 has a significant role in the physiology of neurons and is potentially important in memory and learning.

Amino Acid Sequence↗

PubMed2001

The effect of cricothyroid muscle action on the relation between subglottal pressure and fundamental frequency in an in vivo canine model.

The relation between subglottal pressure (Ps) and fundamental frequency (F0) in phonation was investigated with an in vivo canine model. Direct muscle stimulation was used in addition to brain stimulation. This allowed the Ps-F0 slope to be quantified in terms of cricothyroid muscle activity. Results showed that, for ranges of 0-2 mA constant current stimulation of the cricothyroid muscle, the Ps-F0 slope ranged from 10 Hz/kPa to 60 Hz/kPa. These results were compared to similar slopes obtained in a previous study on excised larynges in which the vocal fold length was varied instead of cricothyroid activation. A physical interpretation of the Ps-F0 slope is that the amplitude-to-length ratio of the vocal folds decreases with CT activity, resulting in a smaller time-varying stiffness. In other words, there is less dependence of F0 on amplitude of vibration when the vocal folds are long instead of short.

Animals↗

PubMed2001

Giant ethmoid osteoma with orbital extension, a nasoendoscopic approach using an intranasal drill.

OBJECTIVE: Ethmoid osteoma is a slow-growing, benign, and encapsulated bony tumor. Symptoms occur earlier than with osteomas of the frontal sinus because of the small volume of the ethmoid sinus. Interestingly, orbital extension is uncommon. Treatment remains controversial, with open procedures typically being used. In this article, we present a less invasive yet safe and effective approach to treatment. STUDY DESIGN: A nasoendoscopic approach using a Stammberger-Saches intranasal drill was developed for treatment of patients with ethmoid osteoma, with or without orbital extension. Between 1995 to 1999, seven patients underwent the new surgical procedure. METHODS: All procedures were performed under general anesthesia. Using 0 degrees and 30 degrees endoscopes, surface anesthesia of the nasal mucosa was performed, the anterior ethmoid cell was resected, and the whitish osteoma found. The osteoma was drilled out inferolaterally to superomedially. In the patient with orbital extension, a double-ended blunt elevator was used to separate the remaining osteoma from the lamina papyracea and to push the residual osteoma medially toward the nasal septum. With alternate drilling and elevation, the osteoma was gently removed. The surgical site was then packed. RESULTS: The method successfully treated all patients. There were no major complications. The single patient with orbital extension had mild postoperative periorbital ecchymoses. Nasoendoscopy showed normal epithelialization 4 to 6 weeks after surgery. Computed tomography showed no residual tumors 6 months after surgery. CONCLUSION: The 30 degrees nasoendoscopic approach using an intranasal drill provides a good operative field and is a safe and effective technique, with the potential to become the treatment of choice in selected cases.

Adult↗

PubMed2001

Matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 gene expressions and their differential regulation by proinflammatory cytokines and prostaglandin in nasal polyp fibroblasts.

Chronic inflammation of the paranasal sinus leads to nasal polyp (NP) formation. In this study, we investigated the effect of stimulation of the proinflammatory cytokines interleukin-1alpha (IL-1alpha) and tumor necrosis factor-alpha (TNF-alpha) and prostaglandin (PG) E2 on the production of messenger RNA (mRNA) of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-I (TIMP-1) in nasal polyp fibroblasts (NPFs) and nasal mucosa fibroblasts (NFs). The mRNAs of IL-1alpha, TNF-alpha, MMP-1, and TIMP-1 in 40 surgical specimens of NPs were studied by in situ hybridization to corroborate the in vitro findings. The results indicated a significant amount of constitutive MMP-1 mRNA in NPFs and cytokine-induced MMP-1 steady-state mRNAs in NFs. The effect of stimulation of cytokines on TIMP-1 mRNA synthesis was unremarkable in NPFs and NFs. Exogenous PGE2 enhanced cytokine-stimulated MMP-1 mRNA synthesis in NPFs. In situ hybridization revealed that cells expressing MMP-1 and TIMP-1 mRNAs (primarily plasma cells, fibroblasts, and endothelial cells) gathered around areas with loose stroma, suggestive of rapid extracellular matrix degradation. These data suggest that the pathogenesis of nasal polyposis could be related to production of MMP-1 and consequent promotion of matrix collagenolysis.

Cytokines↗

PubMed2001

Soluble adhesion molecules and cytokines in tumor-associated tissue eosinophilia of nasopharyngeal carcinoma.

The phenomenon of tumor-associated tissue eosinophilia (TATE) is seen in some cases of nasopharyngeal carcinoma (NPC) and is characterized by the eosinophils breaking through the vascular wall and pervading the tumor stroma. The margination and trans-endothelial migration of eosinophils in a typical inflammatory reaction depend on the activating effects of certain cytokines and the expression of adhesion molecules on the eosinophils and endothelial cells. In order to investigate whether the adhesion molecules and activating cytokines play a role in eosinophil tumor infiltration, we measured the serum levels of 3 adhesion molecules, intercellular adhesion molecule-1, E-selectin and vascular cell adhesion molecule-1, and 2 cytokines, IL-3 and IL-5, in 60 NPC patients and 40 normal healthy subjects. We found that the NPC patients had higher serum levels of all three soluble adhesion molecules than the normal subjects but the levels of adhesion molecules failed to correlate with the TATE phenomenon. The levels of IL-3 and IL-5 appeared not to differ between the NPC and control groups. We postulate that the three soluble adhesion molecules do not play a major role in TATE and that their elevation in serum may be due to local and/or systemic immune responses.

Adult↗

PubMed2001

Inducing vocal register transition in an in vivo evoked phonation canine model.

BACKGROUND AND PURPOSE: The nature of vocal registers is still a subject of controversy. The purpose of this study was to demonstrate the induction of timbre transition of vocal register in an in vivo evoked phonation canine model and thereby confirm vocal register transition as a laryngeal event. MATERIALS: A canine midbrain stimulation evoked phonation model was used in this study. To repeat a low-pitched evoked phonation in the model, the low activity of the thyroarytenoid (TA) muscle and coordinate actions of other intrinsic laryngeal muscles were kept in a consistent condition by stimulating the same midbrain point with the same electric current intensity at the same timing in the respiratory cycle. The cricothyroid (CT) muscle was activated with an electrical current delivered directly to the muscle during the evoked phonation. Under constant subglottal pressure, CT muscle activity was varied while changes in vocal register of the evoked phonation were monitored. RESULTS: The fundamental frequency (F0) of the evoked phonation increased as the stimulating current to the CT muscle increased. In addition to the increase in F0, data collected from six animals demonstrated that timbre register transition was induced by a stepwise increase of current to the CT muscle. The abrupt escalation of F0 and sudden change in sound quality, which could be verified perceptually, manifested the register transition. Frequency spectrum analysis showed that the sound in the modal register contained abundant harmonics that were different from those of the sound in the falsetto register, which contained fewer harmonics. CONCLUSION: The results of this study indicated that intrinsic laryngeal muscles (especially CT and TA muscle interactions) regulate timbre-register transition in a canine model.

Animals↗

PubMed2001

Nasal schwannoma: a case report and clinicopathologic analysis.

According to the literature, half of the schwannoma cases occur in the head and neck areas and only less than 4% occur in the sinonasal tract. In this case, a 39-year-old male patient, with a-year-long progressive left side nasal obstruction and purulent rhinorrhea, is presented. The CT reveals a mass filling the left nasal cavity and nasopharyngeal space, with bony erosion of the inferior turbinate and medial maxillary bone. During surgical intervention, the mass is found to originate from the medial side of the left middle turbinate with maxillary sinusitis and inferior turbinate atrophy. The pathological examination reveals a noncapsulated tumor with palisading cellular arrangement and high cellular density. The pathological findings and nervous origin of the tumor are discussed after an extensive review of the literature.

Humans↗

PubMed2001

Vocal fold abnormalities in laryngeal tension-fatigue syndrome.

This study sought to use videostrobolaryngoscopy to clarify possible biomechanical causes of dysphonia in patients with laryngeal tension-fatigue syndrome, a chronic functional dysphonia due to vocal abuse and misuse. The videostrobolaryngoscopic records of 301 laryngeal tension-fatigue syndrome patients were reviewed. The focus of observation was the visual characteristics of the mucus layer, vessel dilatation or neovascularization on the surface of vocal folds, abnormal glottal closure, and bilateral vibratory asymmetry. Abnormal findings on the vocal folds, especially during vibration, were noted in 270 cases (89.7%). Most patients (222, 73.8%) had multiple abnormalities. The results of this study suggest that chronic vocal overuse under excessive laryngeal muscle tension can cause phonotrauma and result in biomechanical property changes in the vocal fold's cover. These changes would hinder the regular vibration of the vocal folds, increase irregularities in voice signals, and worsen the symptoms of dysphonia.

Adolescent↗

PubMed2000

Evaluation of linkage of markers on chromosome 6p with schizophrenia in Taiwanese families.

Previous studies have indicated possible linkage of schizophrenia with chromosome 6p21-24. In an attempt to replicate these findings, we studied the linkage of schizophrenia with nine markers on chromosome 6p21-24 in 39 Taiwanese schizophrenic nuclear families with at least two affected siblings. Two diagnostic models (narrow: Diagnostic and Statistical Manual of Mental Disorders-IV schizophrenia only; and broad: including schizophrenia, schizoaffective, and other nonaffective psychotic disorders) were used to define the disease phenotypes. With the broad and narrow diagnostic models, the marker D6S296 produced maximum two-point lod scores of 1.46 (straight theta = 0.2) and 1.35 (straight theta = 0. 2), respectively, in the recessive inheritance model. Assuming locus heterogeneity, a multipoint lod score of 0.85 was obtained between markers D6S296 and D6S277 under the narrow/recessive model. Maximum nonparametric lod scores of 1.25 ( p= 0.09) and 1.36 (p = 0.08) were observed, but still not statistically significant, at D6S296 in the narrow and broad diagnostic models, respectively. Both two-point analysis of the dominant model (lod score 0.85) and nonparametric analysis (lod score 1.25) showed a mild peak lod score appeared at marker D6S 285 as well. The results add some support to the suggestive linkage of schizophrenia with markers in the regions of chromosome 6p22 and 6p24 in an ethnically distinct Taiwanese sample. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:74-78, 2000.

Adolescent↗

PubMed2000

Bacterial morphotypes and early cellular responses in clinically infected and non-infected sites after combination therapy of guided tissue regeneration and allograft.

OBJECTIVES: To compare the bacterial morphotypes and early cellular responses in periodontally treated sites with and without pus formation after a combination of guided tissue regeneration (GTR) and allograft therapy. METHODS: 45 subjects with 80 sites having periodontal lesions with moderate to deep pockets and angular bone defects participated. 28 treated sites in 25 patients were included in the studies. 14 sites suffered from symptoms and signs of infection with pus formation during the healing period were assigned to the pus (P) group. Another 14 sites had asymptomatic healing and were assigned to the non-pus (NP) group. The GTR membranes were retrieved 4-6 weeks after surgery and processed for SEM examination. The bacterial morphotypes on the membranes were observed and photographed. Bacterial adhesion score (BAS, 0-5) and the presence of leukocytes and fibroblasts were estimated from photographs. RESULTS: The results showed that large numbers of bacteria (high BAS) were present on both sides of the coronal 2/3 of the membrane in both groups, irrespective of clinical conditions. At the apical 1/3 of the membrane, moderate numbers of bacteria were still found on the outer side in the P group. The BAS of rod-shaped bacteria were significantly higher in the P group than that of the NP group on the outer coronal 2/3 of the membrane. The frequency of the presence of fibroblasts (18.5%) at the apical 1/3 of the inner (tooth facing) side of the P group was much lower than that of the same location (28.6-29.6%) in the NP group. The presence of leukocytes and fewer numbers of fibroblasts on the GTR membrane were associated with greater BAS for rod- and filament-shaped bacteria. CONCLUSIONS: GTR membranes are commonly colonized by oral bacteria during retention, even on uncomplicated and tissue covered portions. The overt infection clinically (pus group) of the membrane-allograft treated sites is associated with a significantly elevated BAS of rod-shaped bacteria, and may be closely related to the occurrence of its adverse early healing responses (inflammation, pus formation, fewer fibroblasts and greater accumulation of leukocytes).

Adult↗

PubMed2000

Bioequivalence study of tramadol by intramuscular administration in healthy volunteers.

Tramadol hydrochloride (CAS 36282-47-0) is a centrally acting analgesic agent binding to mu opiate receptors. The bioavailability of a new tramadol hydrochloride injection (Limadol) was compared with a commercially available reference product by intramuscular administration in twelve healthy Chinese male volunteers by a standard two-way cross-over trial. Each volunteer received a single 100 mg injection of tramadol HCl in each phase. The bioavailability was compared using the area under the plasma concentration-time curve from time 0 to 30 h (AUC0-30), the area under the plasma concentration-time curve from time 0 to infinity (AUC0-infinity), peak plasma concentration (Cmax), and time to reach peak plasma concentration (Tmax). No statistically significant difference was observed between the Tmax, Cmax, AUC0-30 and AUC0-infinity of the two preparations. It is concluded that test and reference formulations of tramadol hydrochloride are bioequivalent for both the extent and rate of absorption after a single intramuscular injection.

Absorption↗

PubMed2000

Biological effects of cementum and bone extracts on human periodontal fibroblasts.

BACKGROUND: Non-collagenous proteins of mineralized tissues play important roles in bone induction during mineralization and in regulating the activity of many types of mesenchymal cells. This study was conducted to determine the effects of acetic acid extracts of bone and cementum on alkaline phosphatase (ALPase) activity and in vitro mineralization of cultured human periodontal fibroblasts (hPF). METHODS: Alveolar bone and cementum obtained from clinically healthy subjects were extracted by a solution containing 0.5 M acetic acid and enzyme inhibitors. Osteoblastic phenotypes of hPF were assayed by ALPase activity, gene expression of bone marker proteins, and the ability to produce in vitro mineralization in culture media containing 50 microg/ml ascorbic acid, 10 mM sodium beta-glycerophosphate, and 10(-7) M dexamethasone. The effects of cementum and bone extracts on the expression of osteoblastic phenotypes in hPF were also determined. RESULTS: Many protein components, varying in molecular weight from 10 to 14 to 120 kDa, were detectable in 10% SDS-PAGE of both cementum and alveolar bone extracts. The hPF cells were found to exhibit a moderate ALPase activity when compared with rat osteosarcoma (ROS) 17/2.8 cells under the same experimental conditions. Gene expression for ALPase, osteocalcin bone sialoprotein, osteopontin, and BMP-7 at mRNA message was detected by RT-PCR in hPF and ROS 17/2.8 cells. The confluent hPF and ROS 17/2.8 cells showed evidence of calcium deposition in the extracellular milieu at 30 and 15 to 30 days' cultures, respectively, under a mineralization medium. The hPF appeared to form mineralized foci with morphological characteristics different from the mineralized nodules produced by ROS 17/2.8 cells. The addition of low concentrations (5 microg/ml) of either cementum or bone extract produced an increase in the size and number of mineralization spots, as well as greater ALPase activity in both hPF and ROS 17/2.8 cultures during the observation periods. CONCLUSIONS: These results suggest that hPF possess certain mineralizing phenotypes, and that acetic acid extracts of bone and cementum contain components capable of stimulating osteogenic differentiation of hPF.

Acetic Acid↗

PubMed2000

The clinical applications of Mini-Mental State Examination in geropsychiatric inpatients.

OBJECTIVE: This study investigated the association between Mini-Mental State Examination (MMSE) scores and diagnosis, computerized tomographic scans or electroencephalogram findings in geropsychiatric inpatients (age > or = 65). METHOD: We analyzed the MMSE records of patients sixty-five and older who had been hospitalized in our psychiatric ward during a nine-year period. Case data were collected by review of chart records. RESULTS: In these patients, MMSE scores were significantly different among the seven diagnostic groups included. Demented patients had the lowest MMSE scores. Patients who had abnormal findings on computerized tomographic scans or electroencephalogram had lower MMSE than patients with normal findings. CONCLUSION: Our findings suggest that the MMSE is a useful screening instrument for organicity in the geropsychiatric inpatients. However, because of the lower average MMSE score in geropsychiatric inpatients, the optimal cut-offpoint of MMSE for dementia should be lower than those used in other populations.

Aged↗

PubMed2000

Gel-filtrated fractions of alveolar bone extract contain factors promoting cell attachment and a mitogenic effect on periodontal ligament fibroblasts.

The purpose of this study was to investigate the effect of acetic acid-extracted bone proteins on human periodontal ligament fibroblasts (hPF) with respect to mitogenic and cell attachment promoting activity. Alveolar bone was harvested from healthy donors and subjected to 0.5 M acetic acid extraction, dialysis and lyophilization, and gel filtration. Promotion of cell attachment and stimulation of DNA synthesis by the crude extract and gel-filtrated fractions were studied in cultured hPE Many protein components, varying in molecular weight from 10-14 to 120 kDa, were detectable in 10% SDS-PAGE of the extract. Gel filtration of bone extract disclosed four fractions with molecular weights of 55, 34, 29 and 19-20 kDa. Both the 34 and 55 kDa fractions at a concentration of 5 microg/ml, but not the 29- or 19-20 kDa fractions, were found to promote cell attachment while only the 55 kDa fraction (5 microg/ml) stimulated DNA synthesis of hPF, Both mitogenic activity and the promotion of the cell attachment by gel-filtrated active fractions were resistant to thermal treatment (70 degrees C) and pH (4 to approximately 8) changes. These findings suggest that acetic acid extract of alveolar bone may contain components which are capable of modulating cell attachment and mitogenesis of hPF.

Acetic Acid↗

PubMed1999

Determination of clindamycin in human plasma by liquid chromatography-electrospray tandem mass spectrometry: application to the bioequivalence study of clindamycin.

A simple, sensitive and specific liquid chromatography-electrospray tandem mass spectrometry (LC-MS-MS) method for the determination of clindamycin (I) was developed. Both I and verapamil (II, internal standard) were analyzed using a C18 column with a mobile phase of 80% acetonitrile-0.01% trifluoroacetic acid. Column eluents were monitored by electrospray tandem mass spectrometry. Multiple reaction monitoring (MRM) using the parent to daughter combinations of m/z 425-->126 and 455-->165 was used to quantitate I. A limit of quantitation of 0.0500 microgram/ml was found. The assay exhibited a linear dynamic range of 0.0500-20.0 micrograms/ml and gave a correlation coefficient (r2) of 0.998 or better. The chromatographic run time was approximately 2 min. The intra-batch precision and accuracy of the quality controls (QCs, 0.0500, 0.150, 1.50, 15.0 and 20.0 micrograms/ml) were characterized by coefficients of variation (CVs) of 5.13 to 13.7% and relative errors (REs) of -4.34 to 4.58%, respectively. The inter-batch precision and accuracy of the QCs were characterized by CVs of 4.35 to 8.32% and REs of -10.8 to -4.17%, respectively. The method has successfully been applied to the analysis of samples taken up to 12 h after oral administration of 300 mg of I in healthy volunteers.

Anti-Bacterial Agents↗

PubMed1999

Elevated second-trimester maternal serum hCG in patients undergoing haemodialysis.

Prenatal Down syndrome screening with maternal serum alpha-fetoprotein (AFP) and human chorionic gonadotrophin (hCG) has become common. High levels of maternal serum hCG and low levels of AFP have been associated with an increased risk of fetal Down syndrome. In this paper, we report five pregnancies in patients undergoing long-term haemodialysis, all of whom had false-positive second-trimester Down syndrome screening results. All of our five patients had extremely high levels of maternal serum hCG, but normal AFP values for their gestational age, and all had serious complications during pregnancy.

Adult↗