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Biomedical subjects

L Yang

Publications and source records attributed to L Yang.

At least 757 records · Page 42Linked to original sources
PubMed1992

[Treatment of double primary lung cancers in 23 patients].

Twenty-three patients with double primary lung cancers (10 synchronous, 13 metachronous) were diagnosed from 1967-1988 by operation, pathology or cytology. The incidence of double primary lung cancers was 1.5% (23/1527) among all lung cancers patients admitted during the same interval. Ten of these 23 patients (43.2%) received operative treatment. The synchronous double primaries were treated by limited resection. For the metachronous lesions, the first lung cancer was treated by the standard lobectomy and the second lesion by wedgectomy. The average survival time for the synchronous double lung cancers was 13 months which was similar to that of radiochemotherapy. For the metachronous cancers, the 5-year survival of 5 operated patients was 40%. Only one of the other 8 patients as treated by non-operative means survived for more than 3 years. This shows the superiority of surgery to the non-operative treatment. Pathologic classification of the lesions in this series showed that 10 (43%) had identical types with the majority (6 patients) being of squamous-squamous cell type. In the 13 patients (57%) with different pathologic types 7 were of squamous-adenocarcinomas. Diagnostic criteria, operative method and vigilance to the possibility of double primary lung cancers are also discussed.

Adenocarcinoma↗
PubMed1992

[The variations of PRL, LH, FSH and testosterone in renal disease].

Blood PRL was measured with RIA in 22 males and 19 females with various degrees of renal insufficiency. At the same time, blood LH, FSH, testosterone were studied in all the male patients and 20 sex-age matched healthy subjects. The results showed that the levels of PRL and LH were increased, and the level of testosterone was decreased significantly in male uremic patients. There was a significant negative correlation between PRL and testosterone. All the above parameters were measured again 8-25 days after continuous ambulatory peritoneal dialysis (CAPD) therapy in 5 male uremic patients. The BUN and Cr levels decreased and the clinical manifestations of uremia improved, but the levels of PRL, LH, FSH and testosterone showed no significant changes. The mechanisms of these variations were discussed.

Adolescent↗
PubMed1992

[Chemical constituents of Pedicularis muscicola Maxim].

It is one of the main components in an effective secret recipe for the treatment of snakebite in Mabian, an autonomaus county of the Yi nationality in Sichuan province. Four compounds have been isolated from the herb of Pedicularis muscicola. On the basis of spectrometric analysis and physico-chemical constants, they were identified as pediculariside, D-mannitol, arachidic acid and hentriacontane.

Drugs, Chinese Herbal↗
PubMed1992

A modified procedure for replica plating of mammalian cells allowing selection of clones based on gene expression.

The polyester cloth replica-plating technique for selection of mammalian cell clones was modified by growing cells in colonies on a flexible polytetrafluoroethylene membrane and then transferring them completely to polyester cloth (27-microns mesh), from which a replica was made by allowing cells to transfer to a cloth of smaller pore size (17-microns mesh). Using this technique, two phenotype selection methods are demonstrated here: in situ hybridization for detection of a specific mRNA and a photographic film assay for detection of luciferase expression. Cells were transfected with pSV2AL-A delta 5' in which firefly luciferase cDNA is under the control of the simian virus 40 promoter. The luciferase assay was adapted for colonies on polyester cloth; cells were permeabilized with digitonin to allow access of ATP and luciferin to the cell without disruption of colonies. Clones selected for expression or nonexpression of luciferase by the photographic film assay were positive or negative for expression after isolation from the cloth replica and subsequent growth under conventional culture conditions. The replica-plating procedure described here should be generally applicable to most mammalian cell types. The ability to produce replicas of colonies, combined with in situ hybridization or assays that can be adapted to in situ detection, provides phenotype selection for clones based on gene expression independent of growth characteristics.

Animals↗
PubMed1992

[Surgical treatment for carcinoma of gastric stump--a report on 13 patients].

Thirteen patients with carcinoma of gastric cardia after gastrectomy were treated in our hospital from 1981 to 1990. They comprised 1.3% of 932 cancers of the gastric cardia treated during the same interval. Partial esophagogastrectomy and esophagogastrectomy were performed under the aortic arch in 2 patients. Total gastrectomy was carried out in 8 patients with 7 Roux-Y and 1 end-to-side esophagojejunostomy. In the remaining 3 patients, only exploration was done. In the resected patients, two (20%) were complicated by anastomotic leak which was obviously higher than that by the conventional partial esophagogastrectomy for gastric cardia carcinoma. Due to reflux of bile and pancreatic juice, the incidence of gastric cardiac cancer in gastric stump after Billroth II operation was much higher than that following Billroth I type. Hence, Billroth I type should be the method of choice for patients to be operated by the distal partial gastrectomy. If Billroth I type was not feasible, Roux-Y anastomosis should be the alternative for Billroth II type in order to reduce the possibility of developing cancer in the proximal pouch. The route of entry, either left posterolateral thoracotomy or left thoracoabdominal incision should be resorted to in conformity with the size of the tumor.

Anastomosis, Roux-en-Y↗
PubMed1991

Activation of BPV-1 replication in vitro by the transcription factor E2.

Soluble extracts from uninfected murine cells supplemented with purified viral E1 and E2 proteins support the replication of exogenously added papilloma virus DNA. The E2 transactivator stimulates the binding of the E1 replication protein to the minimal origin of replication and activates DNA replication. These results support the concept that transcription factors have a direct role in the initiation of DNA replication in eukaryotes by participating in the assembly of a complex at the origin of replication.

Aphidicolin↗
PubMed1991

HIV-1 gag-specific cytotoxic T lymphocytes recognize multiple highly conserved epitopes. Fine specificity of the gag-specific response defined by using unstimulated peripheral blood mononuclear cells and cloned effector cells.

CTL directed at the highly conserved HIV-1 gag protein have been described in HIV-1 seropositive persons and may be an important host defense against this retrovirus. Presently only limited data are available regarding the specific epitopes recognized by these CTL. In this study, we have performed a detailed examination of the gag-specific CTL response in three HIV-1 seropositive subjects, using both unstimulated PBMC and cloned CTL. Lysis of gag-expressing targets was found to be mediated by CD3+CD8+ lymphocytes and restricted by class I Ag. Multiple class I Ag were found to restrict gag epitopes in each subject studied, with as many as three of these Ag involved in presenting gag CTL epitopes in a single subject. The majority of gag-specific CTL activity was found to be directed against epitopes in the p24 subunit of the gag protein, with at least seven different HLA class I-restricted CTL p24 epitopes identified in these three subjects. Less CTL activity was directed against p17 subunit of gag and two CTL epitopes were identified in this protein. Although as many as four different epitopes in gag were recognized using CTL from a single subject, none of the epitopes was recognized by CTL from more than one subject. Analysis of gag epitope recognition using cloned CTL demonstrated heterogeneity and specificity not appreciated using unstimulated PBMC. The identification of multiple relatively conserved epitopes in the HIV-1 gag protein and the heterogeneity of CTL responses to this protein may have important implications for vaccine development and our understanding of AIDS pathogenesis.

Amino Acid Sequence↗
PubMed1991

Gas chromatographic determination of aldicarb and its metabolites in urine.

A method is described for the determination of aldicarb and its metabolites (the sulphoxide and sulphone) in urine by gas chromatography with flame photometric detection (GC-FPD). The sample was concentrated with a column containing activated charcoal and Florisil, and then eluted with dichloromethane-acetone (1:1, v/v). The aldicarb and aldicarb sulphoxide in the eluate solution were oxidized to aldicarb sulphone and the total sulphone concentration was determined by GC-FPD after extraction with dichloromethane and clean-up with an activated charcoal column. The detection limit was 0.0024 mg/l. The mean recoveries from spiked urine in the range 0.04-0.12 mg/l were 90.9%, 86.6%, 92.6% for aldicarb, aldicarb sulphoxide and aldicarb sulphone, respectively.

Aldicarb↗
PubMed1991

The influence of limb alignment on the gait of above-knee amputees.

Biomechanical gait tests on above-knee amputees were conducted in which the alignment of the prosthesis was changed systematically. An eight-segment biomechanical model of the above-knee amputee was developed to analyse and present the three-dimensional kinematic and kinetic data obtained. The effects of alignment changes on the above-knee amputees' gait were studied in terms of the angular displacements of the lower limbs, ground reactions and intersegmental moments. It was found that following the alignment changes the angular displacement at the hip joint on the prosthetic side showed compensatory actions by the amputee. The ground reaction force was sensitive to alignment changes, and in particular, the changes in the characteristics of the fore-aft component of the ground force could be related to the alignment changes. The antero-posterior intersegmental moments at the prosthetic ankle and knee joints were evidently influenced by alignment.

Amputation Stumps↗
PubMed1991

Identification and analysis of discrete functional domains in the pro region of pre-pro-transforming growth factor beta 1.

A series of site-specific insertion and deletion mutants was prepared in the pro domain of transforming growth factor beta 1 (TGF beta 1) encoded by simian TGF beta 1 cDNA. These mutants were transiently expressed in COS-1 cells and the ability of each to be properly processed, folded correctly, and secreted was determined by immunoblot analysis of cells and culture supernatants. Insertions in regions corresponding to amino acid residues 50, 154, and 170 blocked secretion; culture supernatants from COS-1 cells showed no immunologically reactive proteins, whereas intact cells contained high levels of the mutant polypeptides. Insertions in the middle portion of the pro domain at residues 81, 85, and 144 affected disulfide maturation of the mature TGF beta 1. An insertion at residue 110, on the other hand, appeared to destabilize the mature TGF beta 1 polypeptide, resulting in degraded growth factor. Relatively small (10 amino acids) to large (125 amino acids) deletion mutations in the pro domain of TGF beta 1, when expressed as the full-length pre-pro-TGF beta 1, appeared to block secretion. By contrast, if the pro domain (designated beta 1-latency-associated peptide [beta 1-LAP]) was expressed independently, deletion mutants in the region 40-110 were readily secreted by the COS-1 cells, whereas deletions in residues 110-210 either destabilized the structure of the protein or blocked its intracellular transport. Cross-linking assays employing radioiodinated TGF beta 1 and biological assays indicate that residues 50-85 of beta 1-LAP are required for association with mature TGF beta 1.

Amino Acid Sequence↗
PubMed1991

Acetylcholine, Ca2+ overload and oscillatory potentials in isolated ventricular myocytes.

The events caused by overdrive-induced calcium overload were studied in guinea pig isolated ventricular myocytes. Overdrive may induce oscillatory potentials (Vos) and a prolonged depolarization (Vex), as well as the underlying currents (Ios and Iex, respectively). Acetylcholine (ACh) reduced or abolished these events, an action which was blocked by atropine. Norepinephrine exaggerated the effects of overdrive, and ACh markedly antagonized such an enhancement. Caffeine at low concentrations increased both Ios and Iex whereas at high concentrations caffeine abolished Ios but increased Iex. Quinacrine abolished both events. Voltage clamp depolarizing steps abolished Ios (and did not reverse it). Thus, the effects of Ca overload are antagonized by ACh in the absence and presence of sympathetic enhancement. Also, the mechanism underlying Ios appears to involve an electrogenic Ca extrusion and not an increase in a nonspecific conductance.

Acetylcholine↗
PubMed1991

[Identification of Yi nationality's secret recipe for treating snakebite].

The authors have investigated and found an effective secret recipe for the treatment of snakebite in Mabian, an autonomous county of the Yi nationality in Sichuan Province. Morphologic identification has shown that the recipe is composed of the herb of Pedicularis muscicola and the rhizome of Polygonum viviparum in the ratio of one to one. To facilitate further application, popularization and improvement of the recipe, its histological characteristics have also been studied microscopically.

Drugs, Chinese Herbal↗