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Biomedical subjects

T T Chen

Publications and source records attributed to T T Chen.

At least 163 records · Page 9Linked to original sources
PubMed1983

Identification and characterization of estrogen-responsive gene products in the liver of rainbow trout.

Injection of male rainbow trout with estradiol induced the production of a major serum protein, vitellogenin (VG), of molecular weight (MW) 170 000. This protein is immunoprecipitable by an antiserum raised against lipovitellin from the eggs. Labelling by incubation of liver cubes of estradiol-treated fish with [35S]methionine and analysis of immunospecific products showed incorporation into two polypeptides of MW 170 000 and 160 000. The peptide patterns generated from these two polypeptides by Staphylococcus aureus V8 protease digestion were identical. Cytoplasmic poly(A)+ RNA of estradiol-treated male liver directs the synthesis of a polypeptide of 160 000 daltons in the reticulocyte cell-free protein-synthesizing system or in Xenopus oocytes. This polypeptide is chemically, immunologically, and electrophoretically identical to the authentic VG polypeptide of 160 000 daltons. Changes in mRNA populations in the liver of male fish following estradiol treatment were detected on gels and by hybridization. On methylmercuric hydroxide gels, a polyadenylated RNA species of about 6300 nucleotides was found in estradiol-treated fish which was absent from the control fish. Data from R omicron t analysis revealed the presence of at least two mRNA sequences of the high frequency class in the RNA of hormone-induced fish and their sizes were determined by Northern blot analysis to be 6300 and 1800 nucleotides, respectively. These observations are consistent with the induction of vitellogenins and at least another estrogen-responsive gene product by estradiol as reported in other egg-laying vertebrates.

Animals↗
PubMed1983

Management of patients with metastatic adenocarcinoma of unknown origin: a Southwest Oncology Group study.

The Southwest Oncology Group evaluated 51 patients with a histologic diagnosis of metastatic adenocarcinoma and an occult primary tumor. Even though all patients received an extensive diagnostic evaluation, only six (12%) primary sites were found. Thirty-six patients whose primary tumor sites remained occult were randomized to receive either 5-FU or combination chemotherapy (5-FU, doxorubicin, and cyclophosphamide [FAC]). There were no responses in either group. The median survival with 5-FU was 105 days and with FAC was 95 days. Toxicity with FAC was more common and more severe.

Adenocarcinoma↗
PubMed1982

Adrenocorticotropin administration during early gestation on conceptus development in swine.

The purpose of this study was to examine the effect of exogenous adrenocorticotropin (ACTH), administered to gilts during early stages of gestation, upon fetal survival and various maternal and conceptus parameters. Forty-eight gilts of approximately 6-7 months of age were bred by means of artificial insemination after detection of the second estrus and randomly allotted to one of 12 treatment-period groups. Treatment consisted of a daily intramuscular injection of 0, 40 or 80 U.S.P. units of a long acting ACTH preparation for a period of five days. The injection periods were 1-5, 6-10, 11-15 or 16-20 days of gestation with day one corresponding to 48 hours post-estrus detection. All gilts were slaughtered at approximately 37 days of gestation. Forty-two of the 48 inseminated gilts conceived. Conception rate was not different (P>.10) among the 12 treatment-period combinations. Percent fetal survival was greater (P<.09) in gilts receiving 80 U.S.P. units of ACTH (82 +/- 4.3%; X +/- SEM ) than in gilts receiving 40 U.S.P. units of ACTH (68.8 +/- 4.5%). The percent fetal survival in the control group (71.7 +/- 3.9%) was not different (P>.10) from either of the two ACTH treatment groups. A significant (P<.05) treatment by period interaction for percent fetal survival was observed. The lowest percent fetal survival (48.0 +/- 9.0%) was observed in gilts receiving 40 U.S.P. units of ACTH on day 11-15 of gestation. No significant (P>.10) differences were detected among the 12 treatment-period combinations for any of the maternal or conceptus parameters measured.

Journal Article↗
PubMed1981

A comparative endoscopic evaluation of the damaging effects of nonsteroidal anti-inflammatory agents on the gastric and duodenal mucosa.

Twenty-five normal volunteers were randomized into five equal parallel groups. Groups I received ibuprofen (2,400 mg./day); group II received tolmetin (2,000 mg./day); group III received indomethacin (150 mg./day); group IV received naproxen (750 mg./day) and group V received placebo (four tablets daily). All drugs were given on a q.i.d. basis except naproxen which was given b.i.d. The doses selected represented the manufacturer's highest recommended dosage for the treatment of arthritic disorders. A single-blind technic was used in which the investigators were unaware of which drug each volunteer was taking. Upper gastrointestinal endoscopy and photography were carried out before and after seven days of administration of each medication. Gastric and duodenal mucosal injury was graded on a 0-4 + scale. Three of the four drugs studied produced essentially equal gastric and duodenal mucosal injury with tolmetin producing the most damage followed by naproxen and indomethacin. Ibuprofen produced gastric mucosal injury equivalent to that seen with naproxen and indomethacin but no duodenal mucosal injury was seen with this drug. Extremely poor correlation was found between subjective symptomatology and endoscopic findings.

Adult↗
PubMed1979

Double Latin square study to determine variability and relative bioavailability of methylprednisolone.

The variability and relative bioavailability of methylprednisolone tablets were evaluated utilizing a double Latin square crossover design in which each of 20 subjects was given four of five treatments. Three different lots of methylprednisolone tablets exhibited virtually identical absorption, with similar ranges and coefficients of variation of some selected bioavailability parameters indicative of lot-to-lot uniformity in bioavailability. Within-lot and between-lot uniformities in bioavailability also were similar, suggesting that the observed variability in serum methylprednisolone levels was not due to manufacturing process variables. With respect to intra-versus intersubject variability, no differences were found for the absorption rate or terminal half-life. In contrast, between-subject variability associated with extent of absorption was greater than that within subjects. Relative to an aqueous suspension, methylprednisolone tablets were fully bioavailable.

Adult↗
PubMed1979

The effects of ibuprofen, indomethacin, aspirin, naproxen, and placebo on the gastric mucosa of normal volunteers: a gastroscopic and photographic study.

The effects of various nonsteroidal antiinflammatory drugs on the gastric mucosa were endoscopically evaluated in 40 normal volunteers. Eight groups, each containing five subjects were designed: aspirin (3600 mg/d); placebo; ibuprofen (1600 mg/d); ibuprofen (2400 mg/d); indomethacin (100 mg/d); indomethacin (150 mg/d); naproxen (500 mg/d); and naproxen (750 mg/d). All volunteers took medication for seven days and gastroscopy was carried out on day one and day eight. All findings were documented by photography. Severe gastric mucosal injury occurred with aspirin (P less than 0.05), both doses of indomethacin, and the higher dose of naproxen. Lesser changes were seen with the lower dose of naproxen, both doses of ibuprofen and placebo. The higher doses of ibuprofen, indomethacin, and naproxen caused a greater degree of gastric mucosal injury, but statistical significance was achieved only with naproxen (P less than 0.01). Subjective gastrointestinal complaints generally correlated with endoscopic pathology; however, nine volunteers had evidence of severe injury to the gastric mucosa with no symptomatology. This was confined to the patients on indomethacin, naproxen, and ibuprofen. Aspirin patients all had some degree of symptomatology but to a lesser degree than expected in view of the endoscopic findings.

Adult↗
PubMed1975

Quantitative cloning of malignant human glioma cells by conditioned medium.

The use of conditioned medium (CM) obtained from monolayer cultures of human glioma cells induced colony formation from single glioma cells in culture. In contrast, no colonies were observed in cultures incubated with nonconditioned standard Eagle's basal medium. The number of colonies formed closely depended on the concentration of CM. The glioma CM not only stimulated colony formation but also induced the formation of fibrillary cell extensions. Culture conditions influencing the production of colony-stimulating factors included cell density and duration of culture medium contact with glioma cells. The colony-stimulating activity (CSA) was stable after freezing and thawing, but decreased 30-40% when CM was exposed to temperatures over 66 degrees C for 30 minutes. In addition, the CSA was filtratable (0.45 mu), dialyzable, and passable through an Amicon PM10 filter, which indicated a molecular weight less than 10,000. The use of CM provided an improved method for quantitative assays of neural tumor cells, based on their colony formation in culture.

Cell Line↗