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Biomedical subjects

C T Lin

Publications and source records attributed to C T Lin.

At least 55 records · Page 3Linked to original sources
PubMed2000

Ultrasonographic measurement of tongue movement during swallowing.

Previous ultrasonographic studies on tongue functions were limited by the possibility of artifacts caused by movement of the submental area during function. Consequently, tongue movements were misinterpreted. A dynamic tongue imaging technique, the cushion-scanning technique, was used to overcome this problem. Later, swallowing was investigated and divided into five phases using cushion-scanning technique-aided M-mode ultrasonograms. In this study, cushion-scanning technique in combination with the B-mode and M-mode ultrasonography was applied to investigate and measure the tongue movement during swallowing in 55 normal persons. The average duration, range of motion and speed of swallowing were found to be 2.43 s, 24.06 mm, and 10.34 mm/s, respectively. The computer-aided B-mode plus M-mode ultrasonography in combination with the cushion-scanning technique is a valuable tool for study of tongue functions.

Adolescent↗
PubMed2000

High-risk HPV DNA detection by Hybrid Capture II. An adjunctive test for mildly abnormal cytologic smears in women > or = 50 years of age.

OBJECTIVE: To determine whether high-risk human papillomavirus (HPV) DNA testing could improve the detection of cervical intraepithelial neoplasia (CIN) and cancer in older women (> or = 50 years old) with mildly abnormal results on conventional cytology. STUDY DESIGN: The study was based on 119 patients aged over 50 (median, 62; range, 50-78) referred for colposcopy with Pap smears reported as atypical squamous cells of undetermined significance (ASCUS) or low grade squamous intraepithelial lesion (LSIL) from February 1997 to September 1998. The presence of high-risk HPV DNA (including HPV types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59 and 68) was determined with the Hybrid Capture II (Digene, Inc., Silver Spring, Maryland) microplate method. Cytologic examination by Pap smear was based on the Bethesda System and, cervical biopsy was done via colposcopy. RESULTS: High-risk HPV DNA was demonstrated in 75.6% (34/45) of patients with LSIL and 52.7% (39/74) with ASCUS. Those who were HPV positive were significantly more likely to have CIN or cancer (odds ratio, 33.40; 95% confidence interval, 11.89-93.97; P < .0001). The sensitivity of HPV assay for detection of lesions more severe than CIN 2 was 100%, specificity 64.8%, positive predictive value 66.7% and negative predictive value 100%. CONCLUSION: The addition of a high-risk HPV DNA assay to cytologic examination appears to provide excellent sensitivity and negative predictive value for early detection of high grade CIN or cancer in older women with minimally abnormal Pap smears.

Age Factors↗
PubMed2000

Patient desire and reasons for specialist referral in a gatekeeper-model managed care plan.

OBJECTIVE: To describe patient desire and reasons for specialist referrals in a gatekeeper-model managed care plan. STUDY DESIGN: Cross-sectional prospective study. PATIENTS AND METHODS: We developed a patient questionnaire to gather demographic data and to gauge patients' desire for specialist referral and their reasons for seeking such referral. The survey was administered at 2 sites--an ambulatory care facility of a university hospital and an internal medicine clinic in a suburban ambulatory care site. Patients asked to complete the questionnaire at the university hospital site were enrolled in a gatekeeper-model managed care plan (called CU Gold); those seen at the internal medicine clinic were enrolled in a group-model health maintenance organization. Patients were asked to complete the 1-page questionnaire in the waiting room before being seen by their primary care physician. RESULTS: Among the 860 CU Gold patients who met the inclusion criteria during the 3-month study period (September to December 1997), 112 (13%) reported a definite desire to see a specialist and 274 (32%) indicated a possible desire to see a specialist at the time of their primary care visit. Compared with the CU Gold patients, significantly fewer patients in the health maintenance organization indicated a definite desire to see a specialist (3% versus 13%), but a similar percentage expressed a possible desire to see a specialist (30% versus 32%). The difference in definite desire for referral between the 2 groups could not be explained by patient or primary care physician characteristics. The principal health concerns for which patients sought referral were musculoskeletal, genitourinary or gynecologic, or dermatologic problems. Need for reassurance (cited by 67% of patients), seeing a specialist before (56%), and believing the primary care physician lacked expertise (49%) were the primary reasons patients sought referral. Seventy-four percent of patients referred by their primary care provider and 54% of those not referred agreed it was a good idea to see their primary care physician first before seeing a specialist. CONCLUSIONS: Patients have a significant desire for specialist referral, driven by their need for reassurance, previous specialist referral, and belief that their primary care physician does not have the requisite expertise. Patients' expectations for referral varied significantly, depending on the healthcare system (academic primary care clinic or health maintenance organization) in which they were enrolled.

Adult↗
PubMed1999

Plasmid linking number change induced by topoisomerase I-mediated DNA damage.

The state of cellular chromatin in response to DNA damage has been examined by monitoring the change in the linking number of circular episomes. COS cells transfected with an SV40-based vector were treated with camptothecin (CPT), a eukaryotic DNA topoisomerase I (TOP1) poison which induces TOP1-mediated DNA damage. Within minutes, a large increase in the linking number (over 10 linking number) of a small fraction (5-15%) of the episomal DNA was observed. A similar CPT-induced increase in plasmid DNA linking number was observed in Saccharomyces cerevisae expressing human DNA TOP1. In this case, the majority of the plasmid DNA can undergo rapid relaxation. The large increase in the plasmid linking number suggests major chromatin structural reorganization in response to TOP I-mediated DNA damage.

Animals↗
PubMed1999

Inhibition of hTAFII32-binding implicated in the transcriptional repression by central regions of mutant p53 proteins.

We previously identified a movable and regulable inactivation function within the central region (CRts247) of a temperature-sensitive p53 (p53(ts)) mutant, p53(N247I). Here we showed that central regions from several p53(ts) mutants behaved similarly, i.e. they repressed a neighboring activation domain only when existing in the mutant status. Using chimeric protein GAL4VP16-CRts247 as an example, we demonstrated that de novo protein synthesis was not required for the reactivation of the chimeric protein, indicating that a post-translational mechanism was involved in the control of CRts247 activity. The CRts247-conferred thermo-regulability did not work via a mechanism demanding either an alteration of the subcellular compartmentalization of or the inactivation of DNA-binding activity of the GAL4 chimera. Further, CRts247 did not function in trans, eliminating the possibility that the observed repression was because of the competition for a putative factor(s) by the mutant p53 domain. Rather, CRts247 bestowed temperature-dependent interaction with hTAFII32 to the VP16 activation domain. In a parallel experiment, CRts247 also caused a large reduction in the affinity of hTAFII32 to the p53 activation domain at the nonpermissive temperature. These results strongly suggested that inhibition of hTAFII32 binding could be one of the mechanisms responsible for the transcriptional repression by mutant p53 central regions.

Mutation↗
PubMed1999

Inversion/dimerization of plasmids mediated by inverted repeats.

In contrast with earlier studies on the lambda and Escherichia coli genomes, recombination between inverted repeats on plasmids is highly efficient and shown to be recA-independent. In addition, the recombination product is exclusively a head-to-head inverted dimer. Here, we show that this recombination/rearrangement event can occur on different plasmid replicons and is not specific to the particular sequence within the inverted repeats. Transcription readthrough into the inverted repeats has little effect on this event. Genetic analysis has also indicated that most known recombination enzymes are not involved in this process. Specifically, single or double mutants defective in Holliday junction resolution systems (RuvABC and/or RecG/RusA) do not abolish this recombination/rearrangement event. This result does not support the previous models (i.e. the reciprocal-strand-switching and the cruciform-dumbbell models) in which intermediates containing Holliday junctions are proposed. Further analysis has demonstrated that the recombination/rearrangement frequency is dramatically (over 1000-fold) reduced if mismatches (2.8 %) are present within the inverted repeats. Mutations in dam, mutH and mutL genes partially or completely restored the recombination/rearrangement frequency to the level exhibited by the perfect inverted repeats, suggesting the formation of heteroduplexes during recombination/rearrangement. Sequencing analysis of the recombination/rearrangement products have indicated that the majority of the products do not involve crossing-over. We discuss a possible mechanism in which blockage of the lagging strand polymerase by a hairpin triggers recombination/rearrangement mediated by inverted repeats.

Base Sequence↗
PubMed1999

A study of diagnostic failure of loop conization in microinvasive carcinoma of the cervix.

OBJECTIVE: The aim of this study was to evaluate the specimen adequacy and the histological interpretation of loop conization for microinvasive cervical carcinoma. METHODS: We retrospectively reviewed the histopathological findings of the original cone specimens together with the final hysterectomy specimens in patients with microinvasive carcinoma of the cervix. From 1990 to 1995, 63 consecutive patients with microinvasive carcinoma of the cervix were included in the study, of which 35 patients underwent loop conization and 28 underwent cold-knife conization. All patients had a hysterectomy. RESULTS: The mean width, depth, and cone volume of the conization specimens were 2.44 cm, 2.15 cm, and 3.96 cm3, respectively, in the loop group versus 2.3 cm, 2.35 cm, and 4.38 cm3 in the cold-knife group. No significant differences were seen between the two groups. The application of loop conization was completed in a single slice in 27 patients (77.1%) and multiple slices by the loop in 8 (22.9%), in spite of the attempt to perform conization in a one-pass application when possible. In assessing these cone specimens microscopically, the rate of transection of tissue was significantly higher in the loop cone than in the cold-knife cone (17.1% versus 0%, P = 0.02). Because of transection of tissue and misorientation, pathologic determination of the depth and width of stromal invasion was undetermined in two loop cone specimens compared with none in the cold-knife cones. CONCLUSION: Our study suggests that cold-knife conization is a preferred method in assessing microinvasive carcinoma of the cervix if multiple applications of loop conization are inevitable.

Adult↗
PubMed1999

Characterization of the dimer-monomer equilibrium of the papaya Copper/Zinc superoxide dismutase and its equilibrium shift by a single amino acid mutation.

The coding region of the copper/zinc superoxide dismutase (Cu/Zn SOD) cDNA from papaya fruit, Carica papaya L. cv. Tainong 2, was cloned into an expression vector, pET-20b(+). The Cu/Zn SOD was expressed in Escherichia coli and purified by His-tag technique. Two active forms of the enzyme (30% dimer and 70% monomer) in equilibrium were observed. The activity of the dimeric enzyme was higher than that of the monomeric form. The thermal inactivation rate constant K(d) values calculated for the dimer and monomer at 90 degrees C were -0.0203 and -0.0216 min(-1), and the half-lives for inactivation were 41.9 and 31.8 min, respectively. This indicated that the dimeric enzyme was more stable than its monomeric form. The dimerization of the enzyme was inhibited under acidic pH (below 3.0) or imidazole buffer (above 0.5 M), whereas it was not affected under alkaline pH (above 9.0). Both activity and forms of the enzyme were not affected by 1-4% SDS. Furthermore, the dimeric enzyme was much more resistant to proteolytic attack after 3 h of incubation at 37 degrees C with trypsin or chymotrypsin. In addition, mutation of the papaya Cu/Zn SOD at position 48 from Leu to Phe (L48F) affected the association of monomer, whereas a mutant with Lys substitution (L48K) at the same position tended to dissociate into monomeric form.

Amino Acid Sequence↗
PubMed1999

A method for custom-contoured cushion design using interface pressure measurements.

The interface pressure distributions between flat foam cushions and the buttocks of seated test subjects were compared to custom-contoured cushion surface shapes generated with a seated-buttock contour gauge. Our hypothesis was that pressure measurements could be used to generate a contour equivalent to that obtained with a force-deflection contour gauge. The study was performed in a university medical center using spinal cord injured (SCI) (12) and elderly (30) test subjects. Interface pressure was measured using a pressure mapping pad. Contour shape was measured using an electronic force-deflection contour gauge. Pressure and contour information were reduced prior to analysis using singular value decomposition. Polynomial regressions were performed on the values in the first singular vectors of the corresponding pressure and contour decompositions. Relationships best described by cubic polynomials were detected between pressure and contour shape suggesting that interface pressure predicts optimal contour shape.

Aged↗
PubMed1999

Suspected nasopharyngeal carcinoma in three workers with long-term exposure to sulphuric acid vapour.

Sulphuric acid vapour has been suspected of being an industrial carcinogen. In this study, a cluster is presented of three patients with nasopharyngeal carcinoma (NPC) who worked in the same building of a telecommunications conveyance station in southern Taiwan with long term exposure to sulphuric acid vapour concentrations as high as 0.18 mg/m3. All three workers were diagnosed with NPC within a 5 month period between September 1992, and March 1993. Compared with 19 other healthy workers from the same building, these three workers with NPC had worked significantly longer in this building than had the others (mean (SD) (years): 12.7 (0.6) v 7.4 (4.4); p = 0.01). With an in situ nucleic acid hybridisation and immunostaining method for colocalised Epstein-Barr virus (EBV) and secretory component (SC) protein among biopsy specimens of these three patients with NPCs, it was found that some tumour cells did not contain EBV and SC protein staining signals. These results indicate that EBV infection is not the only risk factor for NPC and long term exposure to relatively low concentrations of sulphuric acid vapour may be associated with the development of NPC.

Adult↗
PubMed1999

A space-time delay neural network for motion recognition and its application to lipreading.

Motion recognition has received increasing attention in recent years owing to heightened demand for computer vision in many domains, including the surveillance system, multimodal human computer interface, and traffic control system. Most conventional approaches classify the motion recognition task into partial feature extraction and time-domain recognition subtasks. However, the information of motion resides in the space-time domain instead of the time domain or space domain independently, implying that fusing the feature extraction and classification in the space and time domains into a single framework is preferred. Based on this notion, this work presents a novel Space-Time Delay Neural Network (STDNN) capable of handling the space-time dynamic information for motion recognition. The STDNN is unified structure, in which the low-level spatiotemporal feature extraction and high-level space-time-domain recognition are fused. The proposed network possesses the spatiotemporal shift-invariant recognition ability that is inherited from the time delay neural network (TDNN) and space displacement neural network (SDNN), where TDNN and SDNN are good at temporal and spatial shift-invariant recognition, respectively. In contrast to multilayer perceptron (MLP), TDNN, and SDNN, STDNN is constructed by vector-type nodes and matrix-type links such that the spatiotemporal information can be accurately represented in a neural network. Also evaluated herein is the performance of the proposed STDNN via two experiments. The moving Arabic numerals (MAN) experiment simulates the object's free movement in the space-time domain on image sequences. According to these results, STDNN possesses a good generalization ability with respect to the spatiotemporal shift-invariant recognition. In the lipreading experiment, STDNN recognizes the lip motions based on the inputs of real image sequences. This observation confirms that STDNN yields a better performance than the existing TDNN-based system, particularly in terms of the generalization ability. In addition to the lipreading application, the STDNN can be applied to other problems since no domain-dependent knowledge is used in the experiment.

Algorithms↗
PubMed1999

Extrasplenic pseudoaneurysm. The role of color flow Doppler ultrasound in diagnosis.

Pseudoaneurysm of the splenic artery has been rarely reported and the Doppler echocardiographic finding seldom described. Herein we report a rare case of huge extrasplenic pseudoaneurysm, which was detected by color flow Doppler ultrasonography and successfully treated by ligation of the splenic artery and resection of the pseudoaneurysm.

Aged↗
PubMed1999

Superior vena cava syndrome as a complication of transvenous permanent pacemaker implantation.

Venous thrombosis induced by a transvenous permanent pacemaker is a common complication. However, superior vena cava (SVC) syndrome caused by pacemaker leads is only occasionally seen and its prevalence has been estimated to be less than 1 in 1000 pacemaker patients. Herein, we report a Taiwanese patient of high grade AV block, who presented with SVC syndrome 2 years after transvenous permanent pacemaker implantation. This case features fibrotic stenosis of the junction of right brachiocephalic trunk and SVC, and an extensive thrombus formation resulting in complete obliteration of the left brachiocephalic vein. The collateral circulation was so delicate that he still could lead a rather normal life, even if anticoagulant therapy proved to be ineffective from an angiographic point of view.

Female↗
PubMed1999

E-, P-, and N-cadherin are co-expressed in the nasopharyngeal carcinoma cell line TW-039.

The cadherin/catenin complex plays a key role in the initiation of cell-cell recognition, and adhesion, and the elaboration of structural and functional organization in multicellular tissues and organs. It is associated with tumor metastasis and also acts as an "invasion suppressor" of cancer cells. Nasopharyngeal carcinoma (NPC) is notorious for its highly metastatic nature. The expression of the E-cadherin/catenin complex is down-regulated in NPC tumor specimens. To obtain better insight into the intercellular adhesive property of NPC cells, we used immunofluorescence microscopy, immunoprecipitation, and immunoblot analysis to examine the expression of the classical cadherins and beta-catenin in a NPC cell line, TW-039. The results demonstrate a change in the distribution of E-cadherin from cytosolic flakes to cell-cell contacts with increasing time in culture. Between days 1 and 5 after plating, the detergent-insoluble fraction of E-cadherin increased from 20% to 37% of total E-cadherin, and that for P-cadherin increased from 33% to 40%. By contrast, the values for beta-catenin remained unchanged (26% and 25%). Both immunofluorescence and immunoblot studies suggested that P-cadherin may be involved in pioneer contact adhesion of TW-039 cells. Interestingly, E-, P-, and N-cadherin are co-expressed in this cell line. Immunoprecipitation studies also showed that other members of the cadherin family may be involved in the contact adhesion of TW-039 cells.

Blotting, Western↗
PubMed1999

High-risk human papillomavirus deoxyribonucleic acid as an adjunct marker in cervical cytology.

BACKGROUND: This study was designed to determine whether screening for high-risk human papillomaviruses testing could improve the detection of cervical dysplasia and cancer in assistance with conventional Papanicoloau (Pap) smears. METHODS: The study was based on 114 patients with abnormal Pap smears referred for colposcopy from Feb. 1997 to Dec. 1997. The presence of high-risk human papillomavirus (HPV) DNA was determined with the Hybrid Capture method (including HPV types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68). Cytologic examination by Papanicolaou smear was based on the Bethesda system and cervical biopsy was done via colposcopy. RESULTS: Cytologic examination demonstrated high-grade squamous intraepithelial lesions (HSIL) in 24 patients with HPV positive (75%), low-grade squamous intraepithelial lesions (LSIL) in 38 with 61% HPV positive, and atypical squamous cells of undetermined significance (ASCUS) in 52 with 37% HPV positive. Among patients with a cytologic diagnosis of borderline abnormalities (ASCUS or LSIL), those with who were HPV positive were significantly more likely to have cervical dysplasia (both p < 0.05). The sensitivity of combined HPV assay and/or cytology for detection of noninvasive precursor (91%) was significantly greater than those of cytology (68%) or HPV assay (81%) alone. CONCLUSION: The addition of the hybrid capture high-risk HPV DNA assay to cytologic examination of cervical smears appears to increase the sensitivity of cervical screening. Our findings suggest that HPV DNA may be a useful adjunct marker for early detection of cervical dysplasia in women with minimally abnormal Pap smears (ASCUS/low-grade SIL).

Biomarkers↗
PubMed1999

Radical resection and intraoperative radiotherapy for a recurrent endometrial cancer after prolonged remission following aggressive salvage therapy: case report.

The prognosis of recurrent endometrial carcinomas is generally poor, except for isolated vaginal relapse. We report a case of recurrent endometrial cancer in a 58-year-old woman who initially received a type I extended hysterectomy with bilateral salpin-go-oophorectomy and bilateral para-aortic and pelvic lymph node dissection. The first recurrence occurred in the left parametrium 7 months after the primary surgery. The salvage therapy consisted of radiotherapy combined with hormonal therapy (tamoxifen and Megace). Complete remission was achieved initially. Subsequently, the patient accepted six courses of chemotherapy (cisplatin and Adriamycin) for progressive elevation of cancer antigen 125 (CA-125). The CA-125 levels remained elevated with titers fluctuating around 100 U/ml until a second recurrence at the left iliac 75 months following salvage therapy. The second salvage treatment consisted of maximal debulking of the pelvic mass and intraoperative radiotherapy (IORT) followed by four courses of chemotherapy with paclitaxel and carboplatin. Complete remission was again accomplished, with clinical investigations and molecular markers returning to normal. The patient has been clinically free of disease for more than 2 years since the second relapse of cancer. In this particular case, we found that repeated recurrence could occur after a long complete remission following salvage therapy; however, the disease could be recontrolled with further aggressive salvage efforts. A multimodality approach with combinations of radical resection, IORT, and paclitaxel-based chemotherapy can be offered to patients with localized recurrent or repeatedly recurrent endometrial carcinoma after previous cisplatin-based chemotherapy and pelvic radiation.

CA-125 Antigen↗
PubMed1998

G protein beta subunit is closely associated with microtubules.

Previously, we have identified the association of G protein beta subunit (Gbeta) with mitotic spindles in various mammalian cells. Since microtubules are the main component of mitotic spindles, here we have isolated bovine brain microtubules and purified Gbeta subunit to identify the close association of Gbeta subunit with purified brain microtubules and have shown the direct incorporation of Gbeta subunit into the microtubules both in vitro and in vivo. It was found that: (1) microtubular fraction isolated from bovine brain contained Gbeta subunit, (2) coimmunoprecipitation demonstrated that Gbeta subunit could be coprecipitated with tubulin, (3) addition of purified Gbeta subunit into cytosolic extract for microtubule assembly caused direct incorporation of Gbeta subunit into assembled microtubules and increased the association of microtubule-associated proteins with microtubules, and (4) incubation of exogenous Gbeta subunit with detergent-permeabilized cells resulted in direct incorporation of Gbeta subunit into microtubule fibers and depolymerized tubulin molecules. We conclude that G protein beta subunit is closely associated with microtubules and may play an important role in the regulation of microtubule formation in addition to its regulatory role in cellular signal transduction.

Animals↗