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Biomedical subjects

J C Lin

Publications and source records attributed to J C Lin.

At least 199 records · Page 11Linked to original sources
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↗
PubMed1991

Inhibitory effects of acyclic nucleoside phosphonate analogs, including (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine, on Epstein-Barr virus replication.

(S)-9-(3-Hydroxy-2-phosphonylmethoxypropyl)adenine [(S)-HPMPA], (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)-2,6-diaminopurine [(S)-HPMPDAP], cyclic (S)-HPMPA [(S)-cHPMPA], 9-(2-phosphonylmethoxyethoxyethyl)-2,6-diaminopurine (PMEDAP), and (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine [(S)-HPMPC] were examined for their inhibitory effects on Epstein-Barr virus (EBV) replication. The 50% effective concentrations for inhibition of viral DNA replication were 0.16, 0.03, 2.0, 1.5, and 0.08 microM for PMEDAP, (S)-HPMPC, (S)-HPMPDAP, (S)-cHPMPA, and (S)-HPMPA, respectively. The relative efficacies based on the in vitro therapeutic index was (S)-HPMPC (5,000) greater than PMEDAP (1,000) = (S)-HPMPA (1,000) greater than (S)-cHPMPA (136) greater than (S)-HPMPDAP (78). Certain ratios of combinations of (S)-HPMPC with 3'-azido-3'-deoxythymidine produced a synergistic inhibitory effect on EBV genome replication, but others exhibited an antagonistic effect. These results indicate that this series of acyclic nucleoside phosphonate analogs, and in particular (S)-HPMPC, are potent and selective anti-EBV agents in vitro.

Adenine↗
PubMed1991

Expression of the Epstein-Barr virus BamHI A fragment in nasopharyngeal carcinoma: evidence for a viral protein expressed in vivo.

A family of mRNAs that are transcribed rightward through the BamHI A fragment have been detected in C15, a nasopharyngeal carcinoma (NPC) which has been passaged in nude mice. Northern (RNA) blot hybridizations indicate that these RNAs are also expressed in three other NPCs which have been established in nude mice and in an NPC obtained at biopsy. Moreover, hybridization in situ detected transcription from BamHI A in 12 NPCs and 1 Epstein-Barr virus (EBV)-containing carcinoma of the parotid gland. In each case, transcription was detected in all of the malignant epithelial cells. Transcription was not detected in two cases of EBV-positive lymphoma biopsies by in situ hybridization nor in latently infected EBV-positive lymphoblastoid cell lines by Northern blot hybridization. The consistent transcription of these sequences in latently infected epithelial malignancy but not in lymphoid cells suggests that this viral function is associated with latent EBV infection of epithelial cells. Sequence analysis of a cDNA synthesized from the C15 tumor, representing the 3' end of BamHI A messenger RNA, revealed an open reading frame (ORF). Translation of this ORF in vitro produced several peptides that were immunoprecipitated with antisera from patients with NPC. The detection of antibodies to the protein encoded by the ORF present in the BamHI A cDNA indicates that BamHI A encodes a protein which is expressed in vivo and is antigenic.

Animals↗
PubMed1991

Identification and functional characterization of Epstein-Barr virus DNA polymerase by in vitro transcription-translation of a cloned gene.

In order to identify the gene encoding the Epstein-Barr virus (EBV) DNA polymerase, a portion of the BamHI-A fragment containing the fifth leftward open reading frame (BALF5) of the EBV genome was cloned into SP6 and T7 promoter-containing vectors for in vitro transcription-translation. The RNA synthesized in vitro was used to program rabbit reticulocyte lysates, which were analyzed for the synthesis of the putative polymerase polypeptide (110 kDa) and assayed directly for EBV DNA polymerase activity. The polypeptide synthesized by the full-length BALF5 genomic fragment had a molecular mass of 110 kDa. 5'-truncated BALF5 with the first and second ATGs deleted produced 95- and 83-kDa polypeptides, respectively. All three translation products were enzymatically active and displayed resistance to high salt concentrations. The identity of the largest polypeptide as the viral polymerase was established by (i) immunoprecipitation with EBV-positive sera from patients with nasopharyngeal carcinoma and by a rabbit polyclonal antiserum prepared with a synthetic peptide derived from the DNA sequence of BALF5; (ii) identification of a polypeptide of identical size (110 kDa) immunoprecipitated from superinfected Raji cell extracts by these antibodies; and (iii) salt-resistant enzymatic activity which was neutralized by the rabbit EBV antiserum. Thus, BALF5 encodes a functional polymerase identical to that induced in superinfected Raji cells.

Cell Line↗
PubMed1991

Perspectives on health effects of electric and magnetic fields.

Some epidemiological studies have fostered concern about cancers caused by electric and magnetic fields associated with distribution and use of electric power. At present, there is no scientific consensus as to which factors, the electric field and/or magnetic field, are biologically important. Similarly, there is no clear indication whether higher field levels are of greater risk than lower level fields. The complex scientific issues attending health effects of power-frequency electric and magnetic fields would be most effectively resolved through interdisciplinary research involving investigators from biological, medical and engineering research communities. A critical need, at present, is a significant increase in federal funding for research on interaction mechanisms and animal studies, while maintaining efforts in epidemiology but with greater emphasis on confounding factors and known cancer-causing agents.

Animals↗
PubMed1991

Renal osteodystrophy.

The term "renal osteodystrophy" is used to include skeletal disorders of patients with chronic renal failure: osteitis fibrosa, osteomalacia, osteosclerosis, osteoporosis and the frequently associated extraskeletal calcifications. It is the chronic glomerular disease with phosphate retention and resultant hyperphosphatemia on one hand and deficient 1,25 (OH)2 D3 and resultant hypocalcemia on the other to induce secondary hyperparathyroidism. The three most common causes of chronic renal failure in our patients are chronic glomerulonephritis, diabetic nephropathy, hypertensive nephropathy in decreasing frequency, polycystic renal disease occurs in five patients. Other miscellaneous causes include nephrotic syndrome, chronic pyelonephritis, systemic lupus erythematosus, periarteritis nodosa, interstitial nephritis and renal stones. The bone changes are similar in primary and secondary hyperparathyroidism and the incidence of brown tumor is about 3% in the former and 1.5 to 1.7% in the latter. We present one among the 94 dialyzed patients who has long-standing severe chronic renal failure from polycystic kidney disease and develops brown tumor in the mid ulna after 7 years on maintenance hemodialysis. The incidence of brown tumor in our series is about 1.1%. Because of increased longevity of the dialyzed patients, brown tumor from secondary hyperparathyroidism is now more commonly observed. Hyperphosphatemia with serum calcium-phosphate products exceeding plasma solubility of 60 to 75 mg/dl may induce soft tissue and vascular calcification. This explains the much higher incidence of soft tissue calcification in secondary than primary hyperparathyroidism; two of our patients with generalized Monckeberg's type arterial calcification and multiple periarticular calcifications in five patients have been observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[Lennox-Gastaut syndrome with band form heterotopia: a case report].

A 10-year-old girl with developmental delay, mental retardation and intractable seizures is reported. She manifested clinically as Lennox-Gastaut syndrome with unknown etiology before admission. Brain MRI revealed a band-like lesion over the bilateral subcortical region being later recognized as band-form heterotopia. This type of heterotopia may be overlooked easily due to its symmetrical distribution and mild degree of cortical convolutional anomaly. As it is often associated with intractable seizures and psychomotor retardation, the prognosis is poor. This patient responded poor to ketogenic diet and anticonvulsants. We present this case and review the related articles.

Brain Neoplasms↗
PubMed1991

Fournier's gangrene: experience of four cases.

Fournier's gangrene is an acute gangrenous inflammation of the male genitalia. In an 18-month period, four patients with Fournier's gangrene were treated at our hospital. Their ages ranged from 39 to 74 years (average 55.2). The presenting symptoms and signs included pain, swelling and necrosis of the scrotum and perineum, fever and jaundice were also noted. Three patients with the predisposing factor of urinary tract infection or perianal abscess recovered after surgical debridement and antibiotics treatment. Their hospital stay ranged between 13 and 50 days. One patient with diabetes, presenting severe septic shock at arrival, died one day after debridement. From the experience of our cases and review of the literature, early surgical debridement and antibiotics are mandatory for the treatment of Fournier's gangrene.

Adult↗
PubMed1991

[Production and characterization of monoclonal antibody against colon cancer associated antigen in Chinese].

Although many monoclonal antibodies have been made in human colon cancer, none of them are from the Chinese species. Recently, a colon cancer cell line CC-M2 established from a Chinese patient has been completely characterized and used as immunogen to produce monoclonal antibodies. Monoclonal antibodies were produced by standard hybridoma technique. The fusion rate was 95.8%. An isotype IgG1 of high proliferation named as Sam-2 was used in this study. The titers were measured around 10(4). Further studies on MoAb Sam-2 through indirect immunofluorescent and immunoperoxidase tests revealed its good specificity and sensitivity in colorectal cancer tissue. In CEA study, the result indicated that Sam-2 may react on a non-CEA related antigen. For further clinical application, the antigen was identified as a glycoprotein by chemical resistant test. In preliminary studies using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting techniques, Sam-2 could recognize two closed antigens or a dimer antigen with molecular weight 25.2 and 27 Kd respectively.

Animals↗
PubMed1990

Changes in intratumor pH by two heatings.

It is a known fact that pH in rodent tumors decline significantly upon heating most likely due to breakdown of the tumor blood circulation. We recently observed that tumor blood vessels become thermotolerant after being heated with a sublethal thermal dose. The purpose of the present study was to reveal whether heating can reduce intratumor pH when the tumor vessels are thermotolerant. When the SCK tumors of A/J mice were heated at 42.5 degrees C for 1 h, the tumor vessels became most thermotolerant at 18 h postheating, as measured with the 86Rb uptake method. The intratumor pH in the control SCK tumors was 7.05 +/- 0.14 (SD), and it significantly decreased to 6.70 +/- 0.08 (P less than 0.001) after heating at 44.5 degrees C for 1 h. However, when the tumor vessels were thermotolerant, i.e., 18 h after heating at 42.5 degrees C for 1 h, reheating at 44.5 degrees C for 1 h could not reduce the intratumor pH. We concluded that such a failure to increase tumor acidity by a second heating at temperatures as high as 44.5 degrees C was due to vascular thermotolerance developed by the first heating.

Animals↗