Biomedical subjects

C C Lin

Publications and source records attributed to C C Lin.

At least 199 records · Page 11Linked to original sources

PubMed1999

Antioxidant activity of tannin components from Vaccinium vitis-idaea L.

Reactive oxygen molecules have been implicated as important pathological mediators in many clinical disorders and periodontal disease. To provide possible alternative treatment of periodontal disease, six tannins isolated from Vaccinium vitis-idaea L. were evaluated for anti-lipid peroxidation, anti-superoxide formation and free radical scavenging activity. The results showed that cinnamtannin B1 displayed the strongest anti-lipid peroxidation activity, proanthocyanidin A-1 displayed the strongest superoxide scavenging activity, and epicatechin-(4beta--> 6)-epicatechin-(4beta-->8, 2beta-->O--> 7)-catechin had the strongest anti-superoxide formation effect. We conclude that tannins isolated from V. vitis-idaea L. exhibited multiple antioxidant activity, and could be used for the treatment of periodontal disease.

Antioxidants↗

PubMed1999

The penetration of ceftibuten into the respiratory tract.

STUDY OBJECTIVE: To determine the penetration of ceftibuten into various respiratory tissues and fluids. DESIGN: Single-dose, open-label, pharmacokinetic study. SETTING: Veterans Administration Medical Center. PATIENTS: Twelve hospitalized men aged 34 to 75 years with a variety of noninfectious pulmonary symptoms/diseases. INTERVENTIONS: Patients received a single oral dose of ceftibuten, 200 mg, prior to undergoing diagnostic fiberoptic bronchoscopy. Plasma samples for the determination of ceftibuten concentrations were collected pretreatment and up to 12 h postdosing. Nasal secretions, tracheal secretions, BAL fluid, and lung tissue from a biopsy were obtained at bronchoscopy from 2 to 7 h postdosing. MEASUREMENTS AND RESULTS: Mean pharmacokinetic parameters for ceftibuten in plasma were the following: maximum observed plasma concentration (Cmax), 8.77 microg/mL; time to reach Cmax, 2.2 h; area under the plasma concentration-time curve extraploated to infinity, 49.21 microg/h/mL; and terminal elimination half-life, 3.17 h. These parameters were similar to those obtained in studies using healthy volunteers. Mean penetration of ceftibuten into nasal, tracheal, and bronchial secretions was 47%, 50%, and 30%, respectively. Mean penetration into BAL fluid was 81%, whereas penetration into lung tissue was 39%. No patient experienced any adverse effects related to ceftibuten. CONCLUSIONS: Ceftibuten penetrates well into various tissues and fluids of the upper and lower respiratory tracts. The results support the activity of ceftibuten in the treatment of upper and lower respiratory tract infections.

Adult↗

PubMed1999

A quantitative model for designing keyboard layout.

This study analyzed the quantitative relationship between keytapping times and ergonomic principles in typewriting skills. Keytapping times and key-operating characteristics of a female subject typing on the Qwerty and Dvorak keyboards for six weeks each were collected and analyzed. The results showed that characteristics of the typed material and the movements of hands and fingers were significantly related to keytapping times. The most significant factors affecting keytapping times were association frequency between letters, consecutive use of the same hand or finger, and the finger used. A regression equation for relating keytapping times to ergonomic principles was fitted to the data. Finally, a protocol for design of computerized keyboard layout based on the regression equation was proposed.

Adult↗

PubMed1999

Improved reliability of the rapid microtiter plate assay using recombinant enzyme in predicting CYP2D6 inhibition in human liver microsomes.

A higher throughput method of screening for the inhibition of recombinant CYP2D6 using a microtiter plate (MTP) assay was evaluated using 62 new chemical entities and compared to data from the dextromethorphan O-demethylase assay in human liver microsomes (HLM). The IC50 values for the two assays closely matched for 53 compounds (85%). Six of the variant nine compounds had higher IC50 values with the recombinant enzyme, whereas three had lower IC50 values with the recombinant enzyme. When the inhibition with the recombinant enzyme was determined at various time points, the IC50 values increased as the duration of the incubation increased for the six compounds with higher IC50 values in the MTP assay. The IC50 values at 10 min matched more closely the IC50 values in HLM (95% compared with 85%). For three compounds that showed comparable IC50 values in the two assays, and the three compounds with lower IC50 values in the MTP assay, the IC50 values did not change over time. These results suggest that the six compounds that showed higher IC50 values in the MTP assay at 45 min are substrates for CYP2D6. Using known CYP2D6 substrates, a similar phenomenon was observed, i.e., inhibition curves shifted to higher IC50 values as incubation time increased. These results indicate that the higher throughput MTP assay is more comparable to HLM if the IC50 values are determined at 10 min rather than the recommended 45 min. Furthermore, data acquisition at multiple time points may indicate if a compound is a potential substrate or metabolism/mechanism-based inhibitor for the enzyme.

Cytochrome P-450 CYP2D6↗

PubMed1999

Expression of nm23 in the primary tumor and the metastatic regional lymph nodes of patients with gastric cardiac cancer.

Tumor recurrence and distant metastasis are major causes of treatment failure in gastric cardiac cancer (GCC). Rapid growth of tumor cells and reduced expression of nm23, a metastatic suppressor gene, in tumor cells have been suggested as two important mechanisms for disease progression of GCC. Therefore, to determine the prognostic value of nm23 expression in GCC, we used immunohistochemistry to examine the expression of nm23 in the pathological sections of both gastric cancer and metastatic lymph nodes from 24 stage III patients. Twenty-two patients had total gastrectomy, and two patients had proximal subtotal gastrectomy with a D2 dissection. Postoperative adjuvant therapy was provided, and the clinical responses were followed routinely. Clinical correlation was evaluated by chi2 with Fisher's exact test and survival by log-rank test. Our results show that the reduced nm23 expression in the primary tumor and in the nodal metastasis is the most useful marker for the poor prognosis of GCC following surgery.

Adult↗

PubMed1999

Acinetobacter baumannii bloodstream infection: clinical features and antimicrobial susceptibilities of isolates.

The number of nosocomial infections caused by Acinetobacter baumannii has increased in recent years. The purposes of this study are to discover the risk factors of transmission to prevent the nosocomial infection of A. baumannii. We retrospectively studied 36 patients with A. baumannii bacteremia at China Medical College Hospital from January 1996 to December 1997. There were 23 males and 13 females. All bacteremia were acquired nosocomially. Malignancy (n = 8) and intracranial hemorrhage (n = 6) were the most common underlying diseases. Only one patient on arterial line disclosed intraarterial catheter-related A. baumannii bacteremia and 3 patients had evidence of A. baumannii pneumonia. Twenty-one patients (58%) had central venous catheters in place at the onset of bacteremia, but none was proven to be catheter-related infection. There were 32 patients (89%) with unknown portal of entry. Multivariate logistic regression analysis revealed that potential risk factors related to A. baumannii bacteremia were prior antimicrobial therapy (P < 0.05). The most common clinical features of A. baumannii bacteremia were, in descending order, fever, leukocytosis, thrombocytopenia and hypotension. Eleven patients (30.6%) died directly from A. baumannii bacteremia. All isolates were resistant to ampicillin, cephalothin, cefonicid and moxalactam. The most alarming evidence was that 19% of isolates showed resistance to imipenem. Our findings emphasized that A. baumannii bacteremia had the following characteristics: usually acquired nosocomially, unknown portal of entry, and high multiresistance, especially the increasing resistance rate to imipenem. Imipenem must be reserved as a last-line agent to treat A. baumannii infections, so we want to suggest that the treatment of choice for A. baumannii is gentamicin, amikacin or ceftazidime.

Acinetobacter Infections↗

PubMed1999

Interleukin-1 beta in oral submucous fibrosis, verrucous hyperplasia and squamous cell carcinoma tissues.

Interleukin-1 beta (IL-1 beta) has been proven to be a multi-effect mediator of inflammation including in the promotion of inflammatory cells to move from blood to inflamed tissues, the regulation of the synthesis and decomposition of extra-cellular matrix, and indirectly in causing bone resorption and inhibition of bone growth. In this study, the amounts of IL-1 beta in the biopsied specimens of normal oral mucosa, oral submucous fibrosis (OSF), oral squamous cell carcinoma (OSCC), and verrucous hyperplasia (VerH) were quantified by ELISA. The results showed that the amounts of IL-1 beta (pg per mg tissue, mean +/- SD) in normal oral mucosa, OSF, OSCC, and VerH were 1.07 +/- 0.53, 0.76 +/- 0.56, 4.37 +/- 0.87 and 3.97 +/- 1.93 respectively. There were no significant differences (p > 0.05, Mann-Whitney U Test) between the amounts of IL-1 beta in normal oral mucosa and OSF, and between VerH and OSCC. However, a significant difference in IL-1 beta level was found (p < 0.001) between normal oral mucosa and OSCC or VerH. Immunohistochemistry staining technique using antibody against IL-1 beta showed positive staining in hyperplastic epithelium (VerH) and tumor cells of OSCC. These results might suggest a correlation between the amounts of IL-1 beta in oral precancerous and cancerous lesions and cell transformation. On the other hand, the amount of IL-1 beta did not change significantly as OSF progressed. Thus, IL-1 beta levels may not be useful to gauge the seriousness of fibrosis, but the gradual increase in IL-1 beta level from normal oral mucosa through VerH to OSCC suggests that IL-1 beta may play an important role in oral carcinogenesis.

Adult↗

PubMed1999

Serum cholesterol levels and prevalence of hypercholesterolemia in school-aged Taiwanese children and adolescents: the Taichung Study.

BACKGROUND: Atherosclerosis has become one of the leading causes of death in Taiwan. Hypercholesterolemia is a major risk factor for coronary atherosclerosis. To evaluate the mean total cholesterol values and the prevalence of hypercholesterolemia in school-aged Taiwanese children and adolescents, an epidemiologic survey was conducted. METHODS: After two-stage sampling of 52 primary schools and 26 junior high schools in Taichung City, we randomly selected 3,924 children (2,070 boys and 1,854 girls). Blood total cholesterol (TC), triglyceride (TG) and high-density lipoprotein (HDL)-cholesterol were measured. Response rate was 86.8%. Subjects' ages ranged from seven to 14 years old. RESULTS: From this cross-sectional survey, the following characteristics (mean +/- SD) were documented for boys and girls, respectively: TC, 162 +/- 28 and 165 +/- 29 mg/dl; TG, 74 +/- 33 and 80 +/- 32 mg/dl; HDL-cholesterol, 61 +/- 13 and 59 +/- 12 mg/dl; and low-density lipoprotein (LDL)-cholesterol, 87 +/- 24 and 90 +/- 25 mg/dl. The mean TC across all age groups ranged from 149 to 172 mg/dl for boys and 157 to 170 mg/dl for girls. In boys, the TC concentration was highest at age 11 (172 mg/dl), and in girls was highest at age 7 (170 mg/dl). Borderline hypercholesterolemia (TC > 170 mg/dl) was found in 36.5% of boys (13.5-53.1%) and 39.7% of the girls (28.3-48.6%). Hypercholesterolemia (TC > 200 mg/dl) was found in 9.7% of males (3.1-16.6%) and 10.3% of the females (5.0-14.9%). CONCLUSIONS: The prevalence of borderline hypercholesterolemia was 38.0% for TC and 17.2% for LDL-C, and for hypercholesterolemia, it was 9.9% for TC and 5.8% for LDL-C. The higher TC levels in Taiwanese children were primarily due to higher HDL-C and TG levels.

Adolescent↗

PubMed1999

Porphyromonas gingivalis bacteremia and subhepatic abscess after renal transplantation: a case report.

A uremic patient developed subhepatic abscess, Porphyromonas gingivalis bacteremia and cytomegalovirus viremia after a renal transplantation in mainland China. P. gingivalis infection has been reported to cause gingivitis and periodontitis. Bacteremia due to P. gingivalis, however, has not been reported in the literature. We report herein a case of subhepatic abscess and bacteremia due to P. gingivalis in a renal transplant recepient who was treated successfully with the well functioning renal graft.

Abscess↗

PubMed1999

Association between serum uric acid and cardiovascular risk factors among elderly people in Taiwan.

In order to understand the distribution of serum uric acid and the relationship between serum uric acid and the cardiovascular risk factor among elderly people, a cross-sectional study was conducted in Chung-Shing-Shin-Tseun community in Taiwan in May 1998. All individuals aged 65 and over were collected. A total of 1123 persons, out of 1774 registered residents, were contacted by face-to-face interview. The response rate was 63.3%. However, only 586 respondents had blood tests and completed questionnaires. Analysis in this study was based on these 586 subjects. The mean uric acid values were 7.4 +/- 1.8 mg/dl in men and 6.3 +/- 1.6 mg/dl in women, respectively (p < 0.001). Multivariate linear regression showed that serum uric acid was significantly correlated with sex and body mass index. Simple correlation showed that serum uric acid was significantly correlated with diastolic pressure, total cholesterol, triglyceride and creatinine. Age, systolic pressure and fasting glucose were not related to serum uric acid. In our conclusion, the uric acid values are high among elderly people. The serum uric acid levels are significantly associated with the cardiovascular risk factors among elderly people.

Age Factors↗

PubMed1999

Recent advances in telemedicine.

With continuing advances in information technology, the applications of computers in medicine are increasing rapidly. Modern information technology not only affects the delivery of health care, but also significantly influences the doctor-patient relationship. Since the 1990s, technologic developments in high-bandwidth telecommunications systems and digitizing devices have led to a surge of interest in telemedicine. In recent years, the Internet, with its powerful penetration and scalability, has become an increasingly popular medical information resource and a new platform for telemedicine. The impact of modern technology on the advancement of telemedicine in Taiwan started with the 1995 National Information Infrastructure project, which uses networks of different bandwidths for teleconsultation and distance education programs. In 1998, National Taiwan University and Taipei Medical College in Taiwan, and the University of Pittsburgh and the University of Iowa in the USA, began cooperation on a new Cyber Medical Center (CMC) project that integrates the technologies of multimedia, database management, a multiple-site videoconferencing system, and the World Wide Web. The aim of the CMC is to create a multimedia network system for the management of electronic patient records, teleconsultation, online continuing medical education, and information services on the Web. In the future, telemedicine systems in Taiwan are expected to combine the Internet and cable television to connect clinics, hospitals, insurance organizations, and public health administrations; and, finally, to extend health services to every household.

Humans↗

PubMed1999

Isolation of Japanese encephalitis virus from mosquitoes collected in Northern Taiwan between 1995 and 1996.

Mosquito collections were carried out from May to October in 1995 and 1996 at Yingko and Sanhsia of Taipei County and Chunan of Miaoli County. A grand total of 13,576 mosquitoes consisting of 13 species in 407 pools were processed and inoculated into Aedes albopictus clone C6/36 cell cultures. One hundred thirty seven pools of these showed the presence of viral antigens in the infected C6/36 cell lysates which were identified by the indirect fluorescent antibody test using a monoclonal antibody against Japanese encephalitis (JE) virus. The postive pools, were divided into 97, 20, 1, 8, 1, 1, 7, and 2 pools from Culex tritaeniorhynchus Giles, Aedes albopictus Skuse, Aedes vexans nocturnus (Theobald), Armigeres subalbatus (Coquillett), Culex annulus Theobald, Culex fuscanus Wiedemann, Culex quinquefasciatus Say, and Culex sitiens Wiedemann respectively. The dominant species collected at night was Culex tritaeniorhynchus, while Aedes albopictus was the dominant species collected in daytime. Besides the pigpens, avian habitats are also a dominate source of JE virus in this study.

Animals↗

PubMed1998

Global spiral patterns in galaxies: complexity and simplicity.

A coherent exposition of the density wave theory of galactic spirals is presented in a recent monograph. It is centered on the working hypothesis of quasi-stationary spiral structure, a possibility first proposed by Bertil Lindblad. This hypothesis has since been found to be widely applicable in a number of physical contexts, including the explanation of the Hubble classification system and other categorical classes. Direct empirical support of this hypothesis has been provided especially by the regularity of the infrared images frequently observed in a number of galaxies (e.g., NGC 309), and by the observed amplitude modulation along the spiral arms (e.g., M51, M81, and NGC 1300). The present paper is a brief review of this theory with further clarification of the fundamentals and of certain specific issues raised in the literature. On the theoretical side, the likelihood for the validity of this hypothesis has been supported by modal studies. Emphasis is placed on the widely observed coexistence of a single regular structure in the Pop II objects and the more complex irregular structures in the Pop I objects, a contrast first discovered by Zwicky many years ago in the main disk of M51. It is pointed out that, in both barred and nonbarred spirals, this basic phenomenon may be understood by noting the fact that the microscale of the collisionless system of Pop II stars--i.e., the diameter of the epicycle--is typically on the same order of magnitude as the observed spacing between the spiral arms. The spiral pattern is thus a very compact structure which is unlikely to respond readily to internal and external disturbances of moderate magnitudes. This apparent robustness in structure is suggested by its observed regularity despite the impact from the coexisting Pop I objects with their strong irregular turbulent motions. This physical picture supports Oort's conjecture of a limited role for tidal interaction in most of the spiral structure of galaxies. It also enables us to place in proper perspective a controversy between two schools of thought, with different emphasis placed on intrinsic mechanisms and on tidal interaction. It is primarily a matter of applicability, or frequency of occurrence of the different scenarios proposed. There is, as yet, little observational evidence presented in the literature that would support the need of an interpretation of the global spiral structure in the galactic disk in terms of a fast evolving structure recently generated from a featureless initial state through tidal interaction. Dynamically, the likelihood for realizing such a scenario is also estimated to be quite low. The above discussions are placed in the context of a general point of view much advocated in current scientific literature; namely, the need to analyze alternative mathematical models for diverse physical contexts in the study of "complex" systems and to judge separately the merits of each model on the basis of its empirical confirmation in an appropriate physical context.

Journal Article↗

PubMed1998

Antitumor activity of SCH 66336, an orally bioavailable tricyclic inhibitor of farnesyl protein transferase, in human tumor xenograft models and wap-ras transgenic mice.

We have been developing a series of nonpeptidic, small molecule farnesyl protein transferase inhibitors that share a common tricyclic nucleus and compete with peptide/protein substrates for binding to farnesyl protein transferase. Here, we report on pharmacological and in vivo studies with SCH 66336, a lead compound in this structural class. SCH 66336 potently inhibits Ha-Ras processing in whole cells and blocks the transformed growth properties of fibroblasts and human tumor cell lines expressing activated Ki-Ras proteins. The anchorage-independent growth of many human tumor lines that lack an activated ras oncogene is also blocked by treatment with SCH 66336. In mouse, rat, and monkey systems, SCH 66336 has excellent oral bioavailability and pharmacokinetic properties. In the nude mouse, SCH 66336 demonstrated potent oral activity in a wide array of human tumor xenograft models including tumors of colon, lung, pancreas, prostate, and urinary bladder origin. Enhanced in vivo efficacy was observed when SCH 66336 was combined with various cytotoxic agents (cyclophosphamide, 5-fluorouracil, and vincristine). In a Ha-Ras transgenic mouse model, prophylactic treatment with SCH 66336 delayed tumor onset, reduced the average number of tumors/mouse, and reduced the average tumor weight/animal. In a therapeutic mode in which gavage treatment was initiated after the transgenic mice had developed palpable tumors, significant tumor regression was induced by SCH 66336 in a dose-dependent fashion. This was associated with increased apoptosis and decreased DNA synthesis in tumors of animals treated with SCH 66336. Enhanced efficacy was also observed in this model when SCH 66336 was combined with cyclophosphamide. SCH 66336 is presently being evaluated in Phase I clinical trials.

3T3 Cells↗

PubMed1998

Surveys of HIV-1, HTLV-I, and other sexually transmitted diseases in female sex workers in Taipei City, Taiwan, from 1993 to 1996.

Between 1993 and 1996 in Taipei, Taiwan, we studied the prevalences of HIV-1, HTLV-I, HSV-2, Chlamydia trachomatis, and syphilis infection in female commercial sex workers (CSW) and the pathogens' associated risk factors. Female CSW from nine massage parlors, two karaoke bars (KB), and 22 brothels in Taipei city participated in this study. Two of 557 (0.4%) KB CSWs from those who participated during the period from 1993 to 1994 had HIV-1 infection, whereas no KB CSWs in the periods 1994 to 1995 or 1995 to 1996 had HIV-1 infection. None of the 725 MP CSWs or 291 brothel CSWs who participated in the study between 1993 and 1996 had HIV-1 infection. In contrast, CSWs from brothels had elevated rates of both HTLV-I and active chlamydia infections compared with KB and MP CSWs (p < .05 and p < .005, respectively). KB CSWs showed an elevated rate of HSV-2 infection in the years 1993 and 1994 when compared with CSWs employed by brothels and MPs (p < .005). The prevalence rates of syphilis for CSWs from brothels dropped from 42.8% in the year 1993 to 1994 to 26.3% in the 1995 to 1996 period, whereas for KB and MP CSWs, the rates were < 6% in each of year studied.

Adult↗

PubMed1998

Inhibitors of farnesyl protein transferase. 4-Amido, 4-carbamoyl, and 4-carboxamido derivatives of 1-(8-chloro-6,11-dihydro-5H-benzo[5,6]- cyclohepta[1,2-b]pyridin-11-yl)piperazine and 1-(3-bromo-8-chloro-6,11- dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-yl)piperazine.

The synthesis of a variety of novel 4-amido, 4-carbamoyl and 4-carboxamido derivatives of 1-(8-chloro-6,11-dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-yl) piperazine to explore the SAR of this series of FPT inhibitors is described. This resulted in the synthesis of the 4- and 3-pyridylacetyl analogues 45a and 50a, respectively, both of which were orally active but were found to be rapidly metabolized in vivo. Identification of the principal metabolites led to the synthesis of a variety of new compounds that would be less readily metabolized, the most interesting of which were the 3- and 4-pyridylacetyl N-oxides 80a and 83a. Novel replacements for the pyridylacetyl moiety were also sought, and this resulted in the discovery of the 4-N-methyl and 4-N-carboxamidopiperidinylacetyl derivatives 135a and 160a, respectively. All of these derivatives exhibited greatly improved pharmacokinetics. The synthesis of the corresponding 3-bromo analogues resulted in the discovery of the 4-pyridylacetyl N-oxides 83b (+/-) and 85b [11S(-)] and the 4-carboxamidopiperidinylacetamido derivative 160b (+/-), all of which exhibited potent FPT inhibition in vitro. All three showed excellent oral bioavailability in vivo in nude mice and cynomolgus monkeys and exhibited excellent antitumor efficacy against a series of tumor cell lines when dosed orally in nude mice.

3T3 Cells↗

PubMed1998

Isolation of functional Golgi-derived vesicles with a possible role in retrograde transport.

Secretory proteins enter the Golgi apparatus when transport vesicles fuse with the cis-side and exit in transport vesicles budding from the trans-side. Resident Golgi enzymes that have been transported in the cis-to-trans direction with the secretory flow must be recycled constantly by retrograde transport in the opposite direction. In this study, we describe the functional characterization of Golgi-derived transport vesicles that were isolated from tissue culture cells. We found that under the steady-state conditions of a living cell, a fraction of resident Golgi enzymes was found in vesicles that could be separated from cisternal membranes. These vesicles appeared to be depleted of secretory cargo. They were capable of binding to and fusion with isolated Golgi membranes, and after fusion their enzymatic contents most efficiently processed cargo that had just entered the Golgi apparatus. Those results indicate a possible role for these structures in recycling of Golgi enzymes in the Golgi stack.

Adenosine Triphosphate↗

PubMed1998

Cementless Roy-Camille femoral component.

From 1984 to 1987, a complete, single-layered, porous-coated femoral component (Roy-Camille type) was used for primary cementless total hip replacement in 80 patients. Seventy-two patients (77 hips) with a minimal follow-up of 5 years (mean 7.2 years) were assessed clinically and radiographically. Thigh pain occurred in 4 hips. Osteolysis appeared in 5 hips. Cortical thinning around the femoral component was significant at the proximal and middle levels. In total, 6 femoral components failed, which led to reoperation due to aseptic loosening (4 hips) and septic loosening (2 hips). The hip rating score (modified d'Aubigne and Postel rating system) in the surviving hips progressed from 9.0 (range 6-10) preoperatively to 16.3 (range 12-18) points at the latest follow-up. From this study, we found that the complete, single-layered, porous-coated stem had a low loosening rate after 5 years. Bone ingrowth into the porous coating was found in most of the cases. A lower stress shielding effect in comparison with the complete, multi-layered, porous-coated prosthesis was also noted.

Adult↗