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Biomedical subjects

C M Liu

Publications and source records attributed to C M Liu.

At least 37 records · Page 2Linked to original sources

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↗

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↗

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↗

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↗

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↗

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↗

Interleukin 1beta-secreting cells in inflamed gingival tissue of adult periodontitis patients.

Interleukin 1beta (IL-1beta) is a cytokine with a wide range of biological activities. It is produced by various cell types including macrophages, fibroblasts, and neutrophils. The inflammatory responses mediated by IL-1beta play an important role in periodontal tissue destruction. The purposes of this study were: (1) to determine the location of IL-1beta in inflamed human gingival tissues by the immunofluorescence method; and (2) to correlate this location to the concomitant presence of macrophage or neutrophils by immunohistochemistry. Five patients with moderate to advanced adult periodontitis receiving periodontal phase I therapy were included in this study. One month after phase I therapy, 15 sites with a probing pocket depth >/=5 mm and gingivitis index >/=1 were arranged for modified Widman flap operation. Another three sites with a probing pocket depth </=3 mm and gingivitis index=0 from two gingival healthy subjects who received crown-lengthening operation were also chosen as a control group. After clinical parameter recording, a biopsy of gingival tissues from all sites was obtained during the operation. The gingival specimens were frozen immediately for further immunofluorescent examination of IL-1beta and immunocytochemical localization of macrophages and neutrophils. The macrophages were found to be widely distributed in inflamed gingival connective tissue and near-by pocket wall tissue. The neutrophils were aggregated in pocket wall and were sparsely seen in connective tissue. IL-1beta immunofluorescent reaction was detected with high intensity in gingival connective tissue especially at the subepithelial region. IL-1beta immunofluorescence with low intensity was only occasionally seen in pocket wall tissue. There was a strong association between the presence of macrophages and IL-1beta expression. Similarly, there was a positive association between neutrophils and IL-1beta immunofluorecence. These results suggested that large amounts of IL-1beta are present in inflamed gingival tissues, and that both macrophages and neutrophils are predominate in IL-1beta production in inflamed gingival tissues.

Adult↗

Characterization of dental follicle cells in developing mouse molar.

Dental follicle has been implicated as the origin of alveolar bone, cementum and periodontal ligament, but there is no direct evidence of their cellular lineage. The present pilot study was designed to characterize the phenotype of cultured cells obtained from the dental follicle of neonatal mouse molars. Developing mandibular molars from 6-day-old CD-1 mice were subjected to 1% trypsin in Hank's balanced salt solution. After trypsinization, the dental follicle was enucleated from the tooth germ and separated from the associated epithelial root sheath. Pure dental follicle tissue was cultured in alpha-minimal essential medium containing 10% fetal bovine serum and antibiotics. The nature of the cultured follicle cells was determined in situ by immunocytochemical staining for type I and III collagen, fibronectin, and alkaline phosphatase expression. Earlier phenotypic markers for mineralization such as bone sialoprotein and osteopontin were also examined by in situ hybridization of matched molar tissues. The extracellular matrix proteins (such as type I collagen and fibronectin) were moderately expressed cytochemically. However, type III collagen was strongly stained. Gene expression of bone sialoprotein and osteopontin was detected in sections of mouse molars of similar age. The ALPase activity showed moderate to strong intensity in these primary cultured cells and responded to 1,25(OH)2 vitamin D3 treatment. Cytokeratin stains were not noted in these cells. In conclusion, the 6-day-old dental follicle cells exhibit partial characteristics of a mineralized tissue-forming phenotype even though the expression of osteopontin, type I collagen and fibronectin was low at this stage.

Alkaline Phosphatase↗

Circulating intercellular adhesion molecule 1 (ICAM-1), E-selectin and vascular cell adhesion molecule 1 (VCAM-1) in head and neck cancer.

The sera from patients with nasopharyngeal carcinoma (n = 30), oral carcinoma (n = 22) and laryngeal carcinoma (n = 22) was extracted before treatment. The concentration of circulating intercellular adhesion molecule 1 (ICAM-1), E-selectin and vascular cell adhesion molecule 1 (VCAM-1) was measured by enzyme-linked immunoassay and compared with those from normal subjects (n = 20). The concentration of circulating ICAM-1, E-selectin and VCAM-1 was significantly increased in nasopharyngeal carcinoma. Correspondingly, VCAM-1 and E-selectin were significantly increased in laryngeal carcinoma, whereas only E-selectin was elevated in oral carcinoma. The concentrations of these adhesion molecules did not significantly differ with respect to the early and late stages of these carcinomas. Elevated levels of soluble adhesion molecules in the sera of cancer patients at three different head and neck regions, although appearing to be implicated in these tumour formations, may be unrelated to tumour progression.

Adult↗

Antiandrogen hepatotoxicity in patients with chronic viral hepatitis.

OBJECTIVE: To assess whether patients with chronic viral hepatitis are at an increased risk for antiandrogen hepatotoxicity. METHODS: We retrospectively reviewed 121 prostate cancer patients who received long-term antiandrogen, either flutamide (n = 56) or cyproterone acetate (n = 65), and had normal pretreatment serum alanine aminotransferase (ALT) levels. Serological markers of hepatitis B and C viruses (HBV and HCV) were checked in 42 of the 121 patients. RESULTS: Twenty-two (18%) of the 121 patients had ALT elevations during antiandrogen therapy. Thirteen (59%) of the 22 patients were positive for either one of the two viral markers, including 7 for HBV, 4 for HCV, and 2 for both. This percentage was higher than the combined prevalence rate of positivity for HBV and/or HCV markers (<20%) in Taiwan. There was no significant differences in the percentage of positive makers among the two antiandrogen groups (p = 0.092). Although a higher incidence of hepatotoxicity was noted in the flutamide (13/56, 23%) than in the cyproterone acetate group (9/65, 14%), there were no significant differences between the two groups (p = 0.27). The time period between initiation of antiandrogen and first ALT elevation varied significantly (from 4 to 1,398 days with a median of 151 days). Half of the 14 HBV carriers and all of the 6 patients with anti-HCV developed antiandrogen hepatotoxicity. CONCLUSION: Our limited data suggested that patients with chronic viral hepatitis probably are at a higher risk of developing antiandrogen hepatotoxicity. Close monitoring of liver functions in patients with chronic viral hepatitis is advised if antiandrogen therapy is necessary. However, a large-scale study is necessary for a definitive conclusion.

Aged↗

Relationship of the subgingival microbiota to a chairside test for aspartate aminotransferase in gingival crevicular fluid.

BACKGROUND: The aim of the present study was to evaluate the association between the occurrence of certain specific periodontal pathogens and aspartate aminotransferase (AST) levels in gingival crevicular fluid (GCF). METHODS: Thirty systemically healthy subjects with moderate to advanced periodontitis were selected. Within each subject, the AST contents of GCF from sites with probing depth between 5 mm and 7 mm were measured using a chairside colorimetric test. AST-positive site refers to one that had an AST level > or = 800 microIU. Subgingival plaque samples from one AST-positive and one negative site were collected for microbiological examination. One site with probing depth < or = 3 mm and no gingival inflammation was selected as a healthy control. Clinical parameters of the chosen sites, including the plaque index and gingival index scores, probing depth, and clinical attachment level were measured. Culture and immunofluorescence (IF) were used for detecting common periodontal pathogens, including Actinobacillus actinomycetemcomitans, Peptostreptococcus micros, Campylobacter rectus, Eikenella corrodens, Fusobacterium nucleatum, Capnocytophaga species, Prevotella intermedia, Prevotella melaninogenica, and Porphyromonas gingivalis. Logistic regression was used to analyze the correlation between the AST test and certain specific pathogens. RESULTS: The GCF scores and total cultivable bacterial counts were higher in AST-positive sites than either AST-negative or healthy sites. The prevalence and proportions of specific periodontal pathogens such as C rectus, E. corrodens, F. nucleatum, Capnocytophaga species, P. intermedia, and P. gingivalis were significantly higher in positive than in negative sites. In analyzing the correlation of the proportion of 6 pathogens with the AST test by logistic regression, only P. gingivalis showed a significant positive correlation. The odds ratio of having a high proportion of P. gingivalis in the presence of a positive AST test was 1.21. CONCLUSIONS: The present study showed that at AST-positive sites, there is a higher prevalence and higher proportion of certain periodontal pathogens. Although only the correlation of P. gingivalis and AST values was statistically significant, the results imply that certain periodontal pathogens may be associated with elevation of AST levels in GCF.

Adult↗

Comparison of Nd:YAG laser versus scaling and root planing in periodontal therapy.

BACKGROUND: The Nd:YAG laser has recently been used in the treatment of periodontal disease. However, although a clinical reduction of probing depth and gingival inflammation to this new approach has been reported, it has not been fully evaluated. Interleukin-1 beta (IL- 1beta), a potent stimulator of bone resorption, has been identified in gingival crevicular fluid (GCF), which is closely associated with periodontal destruction. The aim of this study was to compare the effects of Nd:YAG laser treatment versus scaling/root planing (SRP) treatment on crevicular IL-1beta levels in 52 sampled sites obtained from 8 periodontitis patients. METHODS: One or 2 periodontitis-affected sites with a 4 to 6 mm probing depth and horizontal bone loss from 3 adjacent single-root teeth in each of 4 separate quadrants were selected from patients for clinical documentation and IL-1beta assay. Sampling site(s) from each diseased quadrant was randomly assigned to one of the following groups: 1) subgingival laser treatment (20 pps, 150 mJ) only; 2) SRP only; 3) laser treatment first, followed by SRP 6 weeks later; or 4) SRP first, followed by laser therapy 6 weeks later. The GCF was collected and the amount of IL-1beta was assayed by enzyme-linked immunosorbent assay (ELISA). Clinical parameters and GCF were measured at baseline and biweekly after therapy for 12 weeks. RESULTS: An obvious clinical improvement (marked decrease in the number of diseased sites with gingival index > or =2) and reduction of crevicular IL- 1beta were found in all groups. The level of IL- 1beta was significantly lower in the SRP group (P = 0.035) than in the laser therapy group for the duration of the 12 weeks. The laser combined SRP therapy group showed a further reduction of IL- 1beta (6 to 12 weeks after treatment) than either laser therapy alone or SRP combined laser therapy. CONCLUSIONS: Our data suggest that laser therapy appeared to be less effective than traditional SRP treatment. Of the 4 treatment modalities, inclusion of SRP was found to have a superior IL- 1beta response, when compared to other therapies without it. In addition, no additional benefit was found when laser treatment was used secondary to traditional SRP therapy.

Adult↗

Microbiological response of localized sites with recurrent periodontitis in maintenance patients treated with tetracycline fibers.

BACKGROUND: Whether adjunctive tetracycline fibers can provide an additive effect to scaling and root planing in treating non-responsive sites in maintenance subjects is still controversial. Recolonization of the bacteria from untreated sites or from the extracrevicular region may explain the insignificant response to local therapy. The purpose of the present study was to evaluate the microbiological response of sites treated with tetracycline fibers combined with scaling and root planing. METHODS: The study was conducted in a split-mouth design. Thirty patients on maintenance therapy having at least 2 non-adjacent sites in separate quadrants with probing depths between 4 to 8 mm with bleeding on probing, or aspartate aminotransferase enzyme levels > 800 microIU in the gingival crevicular fluid, were treated with scaling and root planing plus tetracycline fibers or with scaling and root planing only. Subgingival plaque samples were collected at baseline, and 1, 3, and 6 months following treatment. A. actino-mycetemcomitans, C. rectus, B. forsythus, E. corrodens, F. nucleatum, P. gingivalis, and P. intermedia were detected by culture, immunofluorescence, or PCR technique. RESULTS: There was a reduction of total bacterial cell count, as well as of certain periodontal pathogens, following treatment. The prevalence of A. actinomycetemcomitans, B. forsythus, and P. gingivalis and the mean proportions of C. rectus, P. intermedia, F. nucleatum, and P. gingivalis decreased after therapy, but there was no statistically significant difference between the 2 treatment groups with respect to bacterial proportions or the number of positive sites. Besides, the pathogens could not be eliminated from the periodontal pocket, and recolonization of the pocket was noted at 3 months post-treatment. CONCLUSIONS: Bacteria located within the cheek, tongue mucosa, saliva, or untreated sites may contribute to reinfection of the pockets and explain the insignificant response to local tetracycline therapy.

Adult↗

Transcriptional control of the pref-1 gene in 3T3-L1 adipocyte differentiation. Sequence requirement for differentiation-dependent suppression.

Preadipocyte factor-1 (Pref-1) is a transmembrane epidermal growth factor-like domain-containing protein highly expressed in 3T3-L1 preadipocytes, but is undetectable in mature fat cells; this down-regulation is required for adipocyte differentiation. We show here that pref-1 transcription is markedly suppressed during adipose conversion and results in decreased Pref-1 RNA levels. Using 3T3-L1 cells stably transfected with Pref-1 5'-deletion constructs truncated at -6000, -2100, -1300, -692, -300, -235, -193, -183, -170, -93, and -45 base pairs, we determined that the -183 to -170 region is responsible for the suppression of the pref-1 gene during adipogenesis. This is distinct from the -93 to -45 sequence important for pref-1 promoter activity in preadipocytes. The placement of a 40-base pair -193 to -154 pref-1 sequence containing the putative SAD (suppression in adipocyte differentiation) element upstream of the SV40 promoter decreased promoter activity by 85% upon adipocyte differentiation, compared with 40% observed with the SV40 promoter alone. The SAD element is therefore sufficient for adipocyte differentiation-dependent down-regulation of a heterologous promoter. A DNA-protein complex was observed when the -193 to -174 sequence was used with 3T3-L1 nuclear extracts in gel mobility shift assays. Competition with oligonucleotides harboring base substitution mutations identified a core sequence of -183AAAGA-179 as crucial for DNA-protein complex formation. UV cross-linking predicts that an approximately 63-kDa protein specifically binds the SAD element.

3T3 Cells↗

Soluble adhesion molecules and cytokines in perennial allergic rhinitis.

BACKGROUND: Increasing evidence suggests adhesion molecules and cytokines in patients with inflammatory airway diseases are involved in steps of entrapment and migration of inflammatory cells. Recently, soluble forms of adhesion molecules and cytokines have been detected in the sera and other body fluids of patients with various diseases. OBJECTIVE: Eosinophilia in nasal mucosa is characteristic of allergic rhinitis. Vascular adhesion molecules expressed on the endothelium are essential for eosinophils to move from the peripheral blood into the sites of inflammation. Herein, soluble forms of vascular adhesion molecules and eosinophil-activating cytokines are measured to investigate the significance of their appearance in the sera with eosinophil infiltration in the nasal mucosa of perennial allergic rhinitis. METHODS: With the quantitative sandwich enzyme immunoassay technique, the sera of 36 patients of perennial allergic rhinitis and 20 nonatopic subjects were used to measure the levels of soluble intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), E-selectin (endothelial leukocyte adhesion molecule-1, sELAM-1), interleukin-3 (IL-3), and interleukin-5 (IL-5). RESULTS: No significant differences in the levels of soluble vascular adhesion molecules were noted between the two groups. Eosinophil-activating cytokines, IL-3 and IL-5, were significantly increased in the group with perennial allergic rhinitis, and were correlated with eosinophil infiltration in nasal scrapings. CONCLUSION: Although the vascular adhesion molecules expressed on the endothelium are necessary for eosinophils to appear in allergic tissues, eosinophil-activating cytokines as IL-3 and IL-5 are likely to be essential for eosinophils to function in tissues. The elevated concentrations of IL-3 and IL-5 in allergic rhinitis may reflect the inflammatory response occurring in the T cell activation and in relation to manifestation of eosinophils.

Adolescent↗

The titan mutants of Arabidopsis are disrupted in mitosis and cell cycle control during seed development.

We describe in this report a novel class of mutants that should facilitate the identification of genes required for progression through the mitotic cell cycle during seed development in angiosperms. Three non-allelic titan (ttn) mutants with related but distinct phenotypes are characterized. The common feature among these mutants is that endosperm nuclei become greatly enlarged and highly polyploid. The mutant embryo is composed of a few giant cells in ttn1, several small cells in ttn2, and produces a normal plant in ttn3. Condensed chromosomes arrested at prophase of mitosis are found in the free nuclear endosperm of ttn1 and ttn2 seeds. Large mitotic figures with excessive numbers of chromosomes are visible in ttn3 endosperm. The ttn1 mutation appears to disrupt cytoskeletal organization because endosperm nuclei fail to migrate to the chalazal end of the seed. How double fertilization leads to the establishment of distinct patterns of mitosis and cytokinesis in the embryo and endosperm is a central question in plant reproductive biology. Molecular isolation of TITAN genes should help to answer this question, as well as related issues concerning cell cycle regulation, chromosome movement and endosperm identity in angiosperms.

Arabidopsis↗

Quantitative analysis of thuringiensin by high-performance liquid chromatography using adenosine monophosphate as an internal standard.

An analytical method for thuringiensin using adenosine monophosphate (AMP) as an internal standard is established. AMP, with high stability and availability, is an appropriate internal standard for thuringiensin quantitative analysis using high-performance liquid chromatography and ultraviolet absorbance detection at 260 nm. A good correlation between the concentration of thuringiensin and the peak-area ratios of thuringiensin to AMP is demonstrated. From this general equation of linear regression line, the concentration of thuringiensin can be assessed in fermentation broth or semi-purified product.

Adenosine↗