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Biomedical subjects

T Wen

Publications and source records attributed to T Wen.

9 recordsLinked to original sources
PubMed1992

[Hepatic segmentectomy using microwave tissue coagulator].

Hepatic segmentectomy using a microwave tissue coagulator guided by intraoperative ultrasonography is a new operative procedure, which our research unit was the first to start using from 1990. Up to now we have performed this kind of operation with success in 26 cases. Our results suggested that the new procedure simplified the original operation and greatly reduced the risk of hemorrhage and iatrogenic spread of the cancer cells during operation. Besides, this operation as a kind of definite anatomic hepatectomy can minimally resect the tumor bearing tissue in a radical fashion, while maximally preserve the tumor-free tissue of the liver.

Adult↗
PubMed1992

The Zavanelli maneuver: a different perspective.

Some obstetricians recommend the Zavanelli maneuver to resolve shoulder dystocia. Descriptions in the literature report an almost automatic ease in performance of the maneuver. We report a case of severe shoulder dystocia in which management with the Zavanelli maneuver and immediate cesarean was extremely difficult. The procedure involved exact reversal of all the cardinal movements of labor, and the delivery required terbutaline, general anesthesia, and added personnel to ensure successful extraction of the fetus. A delivery requiring the Zavanelli maneuver can be difficult to perform and may be worsened by insufficient personnel and inexact reversal of all the cardinal movements of labor.

Adolescent↗
PubMed1991

Clonality and methylation status of the Epstein-Barr virus (EBV) genomes in in vivo-infected EBV-carrying chronic lymphocytic leukemia (CLL) cell lines.

Directly growing Epstein-Barr virus (EBV)-carrying cell lines were established from a chronic lymphocytic leukemia (CLL) patient (PG) on repeated occasions. The lines carried the same ring chromosome 15 as the leukemia cells in vivo and were similarly trisomic for chromosome 12. They all showed the same JH rearrangement, indicating that they had arisen from the same B-cell progenitor. They also had the same single EBV-terminal repeat (TR), indicating that they had been generated by a single EBV infection event. It may be surmised that a single CLL cell had been infected by EBV in vivo and established itself subsequently as a subclone within the CLL population. This subpopulation persists in vivo but does not appear to expand with time. After explantation, it transforms into lymphoblastoid cells and proliferates selectively as immortalized lines. The leukemia-representative CLL lines were phenotypically indistinguishable from the B95-8 virus-transformed normal diploid cells of the patient, established in parallel by in vitro infection. They grew as typical LCL clusters and expressed the same B-cell activation markers. The methylation status of EBV-DNA was different in the CLL lines and the B95-8-virus-transformed LCLs. When Hpall- and Mspl- digested DNA was probed with BamHI C, E, H and W fragments, the CLL lines showed a mixture of methylated and unmethylated restriction fragments as in certain EBV-carrying Burkitt lymphoma (BL) lines. In contrast, the EBV-DNA of B95-8 virus-transformed normal diploid cells was completely unmethylated, as in other LCLs.

Antigens, CD↗
PubMed1991

Predominant rearrangements of the T cell receptor beta-chain gene in blood lymphocyte populations stimulated with autologous tumor cells suggest clonal T cell expansion in two of fourteen cases.

T cell responses against autologous tumors with samples from patients with a variety of tumors were examined. The abilities of T lymphocytes to lyse the autologous tumor cells were analyzed after short-term mixed lymphocyte/tumor cell cultures (MLTC). Southern blot analysis was used to evaluate whether particular rearrangements of the TCR beta-chain gene predominate in these cultures. Tumor specific lysis could be induced in a proportion of the mixed cultures. In two cases enrichment of T lymphocytes with similar TCR beta-chain gene rearrangements was detected after repeated stimulations with autologous tumor cells.

Blotting, Southern↗
PubMed1990

Presence of clonal T cell populations in chronic B lymphocytic leukemia and smoldering myeloma.

Clonality in the non-neoplastic T cell population was investigated in 21 patients with B cell chronic leukemic (B-CLL) or multiple myeloma (MM) by probing for TCR beta chain gene rearrangements using Southern blot analysis. In three patients with a benign form of B-CLL (stage 0), and in one patient with smoldering MM, evidence was found for predominant T cell clones. As cellular immunity against the malignant cells may be important in leukemia, the results are discussed in view of the potential role of T cell immunity in B-CLL and MM.

Aged↗
PubMed1988

A reevaluation of the amino acid sequence of human follitropin beta-subunit.

A collaborative study from two laboratories has been undertaken to re-evaluate the human follitropin beta-subunit sequence (hFSH beta), since areas of uncertainty remain in the wake of two earlier reports. The first report was by Shome and Parlow (1974). The second, by Saxena and Rathnam (1976), proposed revisions for sequence not definitively placed in the first study, as well as some differences in other placements. We have re-examined the sequence of the hFSH beta with more recent methodology. This has led to revision of certain areas of the sequence and resolution of differences between the two earlier proposals. Specifically, an -Ile-Ser- is established at 21-22, Asp at 41, Arg at 44, Lys at 46, and Glu at 111. These were areas of disagreement in the earlier proposals. A definitive placement of the residues around tryptophan-27 has now been obtained by three laboratories. C-terminal heterogeneity was observed with subunits ending at residue 107, 109, or 111. N-terminal heterogeneity has been observed in all preparations examined to date. A significant population of molecules with a proteolytic nick between residues 38-39 is noted. This is very likely an artifact of the collection and processing. The preparations examined in the present studies showed no evidence of residues 112-118 proposed by Saxena and Rathnam.

Amino Acid Sequence↗
PubMed1987

Sulfate and phosphate analysis in glycoproteins and other biologic compounds using ion chromatography. Application to glycoprotein hormones and sugar esters.

An ion chromatography procedure was devised for the simultaneous determination of phosphate and sulfate in the same sample. In order to eliminate interference from zwitterionic compounds (particularly amino acids and peptides) generated during hydrolysis of the phosphate- or sulfate-containing compounds a pretreatment step with a cation-exchange column was required. The detection of sulfate is approximately twice as sensitive as phosphate on a molar basis. The useful working range for sulfate was 200 pmole to 35 nmole with the ion chromatography employed; the range for phosphate was 400 pmole to 65 nmole. Linearity in this range was very satisfactory. Representative analyses are presented for hydrolyzates of several glycoprotein hormones and sugar sulfates and phosphate esters. Replicate analyses were +/- 3.0% or better. The glycoprotein hormone analyses for sulfate did not indicate whole integers per mole, suggesting mixtures of isohormones as has been found by others using chromatofocusing or isoelectric focussing and immunoassay.

Animals↗
PubMed1986

Characterization of cleavage products in selected human lutropin preparations. A protease-sensitive site in human lutropin beta subunit.

Low molecular weight fragments derived from the beta subunit of human lutropin have been frequently observed. These fragments are detected by polyacrylamide gel electrophoresis in sodium dodecyl sulfate following reduction of the disulfide bonds. A sample of human lutropin was identified that had a major portion of its beta subunit showing this proteolytic nick. Over 83% of the subunit was nicked based on reduction, carboxymethylation, and isolation of the low molecular weight fragments. This preparation had 53% of the activity of an intact human lutropin (radioligand assay). The proteolytic nick in the subunit was shown by N-terminal sequencing of the C-terminal fragments to be derived from three clips in a hexapeptide region (residues 44-49) characterized by hydrophobic alkyl side chains. Specific clips were on the amino side of Leu-45 (8%), Val-48 (45%) and Leu-49 (47%). Thus the proteolytic activity, presumably derived from the pituitary during processing, has a substrate specificity reminiscent of the bacterial protease, thermolysin.

Alkylation↗