PubMed Health⌕ Search

Biomedical subjects

J C Lin

Publications and source records attributed to J C Lin.

At least 19 recordsLinked to original sources
PubMed1992

Epstein-Barr viral latency and cell immortalization as targets for antisense oligomers.

The approach of using an antisense oligonucleotide to oppose the synthesis of a single selected viral gene product needed to maintain the EBV episome in non-virus-producing cells appears to be promising not only for possible cure of latent viral infection, but also for reversal of EBV-driven cell proliferation. It is also possible that targeting multiple latent viral genes might mount a synergistic effect that would prove to be more efficient at curing latent infection. However, further work is needed to identify the reasons for the variable results that are observed as well as to prove specificity of the inhibitory effects. Finally, we are also working on other assays and methods to screen compounds rapidly.

Antigens, Viral↗
PubMed1992

Microwave sensing of physiological movement and volume change: a review.

The ability non-invasively to detect and monitor the movement of tissues and organs from outside the body provides many worthwhile areas of potential biomedical applications. Several non-invasive microwave techniques for contact and remote sensing of circulatory and respiratory movements and volume changes have been developed. In general, these systems consist of a microwave generator, a sampling device, a transmitting-receiving antenna, a set of signal-conditioning and processing devices, and a display unit. They operate at continuous-wave frequencies between 1 and 35 GHz and make use of amplitude and phase information derived from the received signal. The average power density of energy radiated by present systems ranges from approximately 0.001-1.0 mW/cm2. These systems are capable of registering instantaneous changes in fluid volume, pressure pulse, heart rate, and respiration rate in contact with body surface or at distances greater than 30 m, or behind thick layers of non-conductive walls.

Blood Circulation↗
PubMed1992

Canadian multicenter randomized clinical trial of chorion villus sampling and amniocentesis. chromosome mosaicism in CVS and amniocentesis samples.

Data on 1040 chorionic villus and 969 amniotic fluid samples were collected from women studied in the Canadian Multicentre Randomized Clinical Trial of Chorion Villus Sampling and Amniocentesis. Cytogenetic results were obtained from 98.0 per cent of chorionic villus samples and from 99.9 per cent of amniotic fluid samples. Level I mosaicism (a single cell with an abnormal karyotype) occurred frequently in both chorionic villus and amniotic fluid samples and appeared to have no clinical significance. Level II mosaicism occurred in 0.9 per cent of CVS mesenchyme and 1.5 per cent of amniotic fluid cultures and in general was not perceived to be of sufficient concern to warrant cytogenetic follow-up studies. Level III mosaicism was reported in 18 CVS cases (15 cytotrophoblast, 1 mesenchyme, and 2 with both cell methods) and in one amniotic fluid case. In all cases but one (fetus with trisomy 18), level III mosaicism was confined to the placenta. Maternal cell contamination occurring with a frequency of 6.4 per cent in the mesenchyme analyses was a concern. This study supports the final report of the Canadian Multicentre Randomized Clinical Trial of Chorion Villus Sampling and Amniocentesis. Cytogenetic analysis of chorionic villus samples appears to be an acceptable alternative to the analysis of amniotic fluid samples. However, because of mosaicism and maternal cell contamination concerns, the examination of both cytotrophoblast preparations and mesenchyme cultures from chorionic villus samples is recommended.

Adult↗
PubMed1992

Unusual causes of obstructive jaundice in children: diagnosis on CT.

Three cases are presented with unusual causes of obstructive jaundice diagnosed on abdominal CT in children under the age of 15 years. All the cases were initially examined by ultrasound which was inconclusive. CT studies were subsequently performed were diagnostic. These cases included hepatocellular carcinoma, a common bile duct web and duodenal hematoma. The first two cases were surgically confirmed, while the third case was proved by clinical follow-up.

Adolescent↗
PubMed1992

Structure-activity relationship between (E)-5-(2-bromovinyl)- and 5-vinyl-1-beta-D-arabinofuranosyluracil (BV-araU, V-araU) in inhibition of Epstein-Barr virus replication.

The structure-activity relationship between (E)-5-(2-bromovinyl)- and 5-vinyl-1-beta-D-arabinofuranosyluracil (BV-araU and V-araU) in inhibition of Epstein-Barr virus (EBV) was evaluated. Both V-araU and BV-araU effectively inhibited EBV replication in virus-producer P3HR-1(LS) cells, as determined by DNA-DNA hybridization. The 50% effective doses (ED50) for viral DNA replication were 0.005 and 0.3 microM for V-araU and BV-araU, respectively. The in vitro therapeutic index was 4000 for V-araU and 1300 for BV-araU. Synthesis of EBV-induced polypeptides with molecular weights of 145,000 (145, 140, 130, and 110 kDa) was significantly inhibited by both drugs. Only V-araU inhibited the synthesis of 85-, 55-, and 32-kDa polypeptides by approx. 50%. Kinetic analysis of inhibition and reversibility of EBV DNA replication after removal of the drugs indicated that BV-araU has a more prolonged inhibitory effect than V-araU. These results indicate that the substitution of H by Br in the 5-vinyl group results in marked reduction in anti-EBV activity while prolonging the drug effect and diminishing cytotoxicity.

Antiviral Agents↗
PubMed1992

Relationship between vascular thermotolerance and intratumor pH.

The changes in blood flow, intratumor pH, and clonogenicity of tumor cells after one and two heatings were studied in SCK tumors of A/J mice. When SCK tumors were heated at 42.5 degrees C for 1 hr, vascular thermotolerance promptly developed and peaked at 18 hr post-heating. The intratumor pH was 7.05 +/- 0.14 (mean +/- S.D.) in control SCK tumors of A/J mice, with a significant decrease (p less than or equal to 0.001) to 6.86 +/- 0.08 and 6.70 +/- 0.08 when heated for 1 hr at 43.5 degrees C and 44.5 degrees C, respectively. However, when the vascular thermotolerance was at its peak, heating at the same doses caused little change in the intratumor pH. When SCK tumors were heated for the first time at 44.5 degrees C for 1 hr and left in situ, the number of clonogenic cells significantly declined. Such a secondary cell death could be attributed to the deterioration of the intratumor environment ensuing from the vascular damage. When the tumor vessels were thermotolerant, however, virtually no secondary cell death occurred after heating.

Animals↗
PubMed1992

Microwave effects on input resistance and action potential firing of snail neurons.

Excitable tissues have been reported to respond to weak microwave (MW) fields, possibly by nonlinear perturbation of a cellular process such as ion conduction across membranes. We sought effects of MW (continuous wave, 2.45 GHz, specific absorption rates 12.5 or 125 mW/g) on input resistances and action potential (AP) intervals of neurons in ganglia of snails (Helix aspersa), at 20.9 +/- 0.1 degrees C. At 12.5 mW/g, input resistance did not change during irradiation, but increased (p < 0.05) afterward. At 125 mW/g, input resistance during irradiation was lower than in unirradiated controls. Serial correlograms changed marginally more frequently in MW experiments than in controls, but the changes had no consistent pattern. The AP firing rate was affected by MW, but the direction was not consistent across cells. When AP generation was modeled as being due to a neuronal input current, MW did not affect its mean, standard deviation, or autocorrelation. Unlike MW, temperature changes caused neurons to respond robustly and reversibly. Threshold for changing input resistance was 0.63 degree C. The data suggest that MW may enhance degenerative effects such as metabolic rundown or loss of ion channel patency, but do not indicate a specific mechanism for MW interaction with neurons.

Action Potentials↗
PubMed1992

Early CT findings of acute cerebral infarction in the middle cerebral artery territory.

For an early and definitive diagnosis of acute cerebral infarction by computed tomography (CT), we retrospectively analyzed the initial CT findings of 14 patients with proven acute middle cerebral artery (MCA) infarction within 4 hours after stroke onset. The following results were obtained: (a) abnormal CT findings could be recognized quite early in 13 patients (92.9%), (b) the most common and earliest finding was loss of defination of the gray-white interface at the lateral margins of the insula. This sign was recognized in 12 patients (85.7%) and could be detected as early as 1 hour after stroke onset, (c) the next common finding was narrowing or blurring of the Sylvian fissure in 10 patients (71.4%) and could be detected 1.5 hours after stroke onset, (d) an obscured outline or partial disappearance of the lentiform nucleus was recognized in 7 patients (50%) and could be detected 1.5 hours after stroke onset, (e) effacement of the cerebral sulci was found in 6 patients (42.9%) and could be detected 2.5 hours after stroke onset, (f) increased density in MCA or its major branches was not seen in our patients.

Acute Disease↗
PubMed1992

Epithelial neoplasm of the colorectum: correlation of histopathological features with cytogenetic studies.

Seven cases of primary rectosigmoid epithelial neoplasm, including a tubular adenoma, a villous adenoma with malignant change and five adenocarcinomas, were cytogenetically studied with short-term cultivation and GTG-banding. The tubular adenoma showed karyotypic normality. The other six malignant tumors were hyperdiploid in chromosomal modal number and showed multiple aberrations. The complexity of chromosomal aberrations increased proportionally to the pathologic stage. No common chromosome change to all of the tumors was found. The most common recurrent chromosome changes were extra gains of chromosomes #7 and #8q, which were found respectively in four of the six malignant tumors. Two recurrent structurally abnormal chromosomes were i(8q) and der(10)t(10;?)(p15;?). No case showed sex chromosome change, except one tumor from a male patient who obtained an extra X chromosome. All these chromosome changes found were consistent with the results reported by other investigators. Deletions of #5q and #17 were nevertheless only found in one and two of our six malignant cases, respectively. No cases showed a deletion of #18q. The possible molecular mechanisms of these recurrent chromosome aberrations were also discussed.

Adenocarcinoma↗
PubMed1992

Postoperative radiotherapy for glioblastoma multiforme.

Between July 1983 and December 1990, 39 patients with pathologically documented glioblastoma multiforme were treated with radiotherapy after biopsy (5 patients) or resection (34 patients). There were 30 males and 9 females ranging in age from 9 to 68 years (median 52). All but one of the 39 patients were treated with 10 MV photons. Whole brain irradiation was delivered through lateral parallel opposed fields for the first 40 Gy, followed by reduced portals to boost the tumor bearing area. The range of tumor dose was 58 to 70 Gy, with a median dose of 64 Gy (33 patients). Treatment was executed at 2 Gy per fraction, 5 days per week for all patients except 2 who received 1.8 Gy per fraction. Eight patients underwent reoperation at least once after radiotherapy due to suspicion of recurrence of the disease. No patients were lost to follow-up: 35 patients had died and 4 were still alive. The median survival time was 11.8 months. The 1- and 2-year survival rates were 49% and 12% respectively. A prognostic factor analysis shows that treatment response and the pre-irradiation Karnofsky status were statistically significant variables influencing survival. The median survival was 28.7 months for patients with complete response, compared with 9.8 months for those with partial response or stable disease (p = 0.002). The median survivals were 13.5 and 9.0 months in high (> or = 70%) and low Karnofsky performance scale (p = 0.04). Smaller tumors, a larger extent of resection, reoperation and younger age were favorable factors with borderline significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Brachial plexus neuropathy associated with scrub typhus: report of a case.

We report on a 20-year-old man who had scrub typhus with the unusual neurologic complication of brachial plexus neuropathy. The clinical features of fever, headache, pneumonitis, eschar, high Weil-Felix OX-K agglutination and Rickettsia tsutsugamushi immunofluorescence titers confirmed the diagnosis of scrub typhus. Brachial plexus neuropathy was proven by an electrophysiologic examination. He had a nearly complete recovery after adequate medical treatment.

Adult↗
PubMed1992

[An animal model for colon cancer metastases to the lung and establishment of metastatic cancer cell line].

Death, in most colon cancer patients, is not caused by their primary tumors. Instead, metastasis is the major cause of morbidity and death. There are few appropriate animal models to investigate the complexity of the metastatic process. Therefore, the pathogenesis of the metastasis process is not clearly understood. We injected SW480 cells into the cecal wall of athymic nude mice to develop an animal model for colon cancer metastasis and to produce a metastasizing tumor. After metastatic foci formed in the murine lung, we established a metastatic cancer cell line, named CC-ML1, by in vitro primary culture. The characteristics of CC-ML1 were (1) a shorter doubling time; (2) a slightly higher metastatic rate and number of colonies; and (3) less morphological variation than those of SW480. Our research suggests that a higher metastatic potential may be found in CC-ML1 than in SW480 after the advanced cycles of the metastatic process. Thus, the primary animal model in this study may be useful in future studies of cells with a high metastatic potential in the pathogenesis of colon cancer metastases.

Animals↗
PubMed1992

Carcinoma of the external auditory canal and middle ear.

Fifty-three patients with carcinoma arising in the external auditory canal and/or middle ear seen at Veterans General Hospitals, Taipei and Taichung in the period between January 1970 and December 1988 were retrospectively reviewed. There were 49 males and 4 females. Their ages ranged from 5 to 80 years, the average being 58 and the median 59 years. In 10 patients the primary site of the tumor was located in the middle ear, in 32 patients it was the external auditory canal, and in the remaining 11, both areas. The most common cancer which occurred in this area was the squamous cell type, accounting for 85% of our cases. The majority of patients had an otorrhea history with duration from 6 months to more than 40 years. Nine patients received surgery alone, 8 irradiation alone, 31 a combination of surgery and radiotherapy. Initial complete regression of the tumor was noted in 100% of the combined therapy group. This was better than surgery (56%) or irradiation alone (60%). Bleeding and infection caused by surgery, and osteonecrosis caused by radiation were the most frequent and severe complications. The actual 5-year survival rate was 33%. Life table analysis showed that only the extent of the disease affected survival significantly. The 5-year survival rates were 23% and 51% for advanced and early stages respectively (p < 0.05). Combined therapy resulted in better local control and survival than operation or radiotherapy alone, but the benefit did not reach a significant level (p = 0.09).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

An animal model for colon cancer metastatic cell line with enhanced metastasizing ability. Establishment and characterization.

We have developed an animal model for colon cancer metastasis and produced a metastasizing tumor after using a microinjection technique to inject SW480 cells into the cecal wall of athymic nude mice during "minilaparotomy." After the metastatic foci formed in murine lung, an in vitro primary culture was performed and a new metastatic cancer cell line, which was designated as CC-ML3, was established. The studies included: 1) the comparison between SW 480 and CC-ML3 in morphology, growth kinetics, seeding and plating efficiency, and karyotype; and 2) carcino-embryonic antigen determination, origination, and metastatic ability of CC-ML3. The results showed that CC-ML3 was significantly different from SW480 in vitro and possessed a high metastatic potential in vivo. This newly developed animal model may thus be useful for studying the biology and pathogenesis of metastasis of human colonic cancer.

Animals↗
PubMed1991

Human papillomavirus type-related DNA and c-myc oncogene alterations in colon cancer cell lines.

Although squamous-cell epithelium is the most frequent target site of human papillomavirus (HPV) infection, a similar infection is demonstrated in columnar epithelial cells in this paper. The papillomavirus expression in three cell lines was detected in colorectal adenocarcinoma of Chinese patients. The HPV-16 and HPV-18 DNA sequences were found in colorectal cancer cell lines, which might suggest the correlation of HPV to the etiology of colorectal cancers. In addition, c-myc oncogene was identified by amplification in all three colorectal cancer cell lines, but only normal germ-line fragments were found in control tissue. The correlation between HPV and c-myc, and the implications of these findings in colorectal cancers are also discussed.

Adenocarcinoma↗