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Biomedical subjects

S Wei

Publications and source records attributed to S Wei.

At least 163 records · Page 9Linked to original sources
PubMed1995

Changes of immune functions after radiation, burns and combined radiation-burn injury in rats.

The changes of several immune functions were observed in rats after they were inflicted with 6 Gy gamma rays irradiation, 15% TBSA full thickness brun and the combination of the 2 injuries. It was found that the functions of thymocytes and splenoctyes suffered the most severe suppression in the 24th to 72nd hour after radiation injury and began to recover on the 7th day. In the rats with burn injury, the suppression on thymocytes and splenocytes were significantly less severe than that after radiation and recovered more rapidly. The effects of combined radiation-burn injury showed several characteristics. The suppression on the thymocytes was more severe with slower recovery as compared with that after single radiation injury only. The suppression on the splenocytes as a whole was similar to that after single radiation injury, but in the early stage after combined injury, the suppression was far more severe than that after radiation. Escharectomy and skin grafting on the burn wounds on the 1st day after combined injury could accelerate the recovery on both the thymocytes and splenocytes. Our findings indicated that the severity of the suppression on the immune functions due to combined radiation-burn injury might depend on the size of the burn wounds.

Animals↗
PubMed1995

A two-year experience with laparoscopic cholecystectomy--a report of 1475 cases from Kunming, China.

Over a 2-year period, from 12 September 1991 to 11 September 1993, laparoscopic cholecystectomy was performed on 1475 patients with benign gallbladder disease in Kunming General Hospital, Yunnan, China. Of these, 28 cases (1.9%) were converted to open surgery. Various complications were documented in 27 instances including extrahepatic bile duct injury in 4 cases (0.3%), postoperative haemorrhage requiring laparotomy in 3 cases (0.2%) and bile leak from cystic duct stump in 1 case (0.07%). There was 1 (0.07%) death in the series. The junction between the gallbladder infundibulum and the cystic duct is an important landmark which laparoscopic surgeons must identify in the course of the procedure. Because the junction remains a comparatively constant landmark, in difficult laparoscopic cholecystectomy, excessive dissection of the bile duct would be unnecessary. During dissection of the hepatic hilus, blund dissection is recommended and the blind use of cautery and haemostasis should be avoided.

Bile Ducts, Extrahepatic↗
PubMed1995

Human T-cell receptor V beta gene polymorphism and multiple sclerosis.

Population-based genetic associations have been reported between RFLPs detected with probes corresponding to the genes encoding the beta chain of the T-cell receptor for antigen (TCRB) and a variety of autoimmune disorders. In the case of multiple sclerosis (MS), these studies have localized a putative disease-associated gene to a region of approximately 110 kb in length, located within the TCRB locus. In the current study, all 14 known TCRBV (variable region) genes within the region of localization were mapped and identified. The nucleotide sequences of these genes were determined in a panel of six MS patients and six healthy controls, who were human-leukocyte antigen and TCRB-RFLP haplotype matched. Nine of the 14 TCRBV genes studied showed evidence of polymorphism. PCR-based assays for each of these polymorphic genes were developed, and allele and genotype frequencies were determined in a panel of DNA samples from 48 MS patients and 60 control individuals. No significant differences in allele, genotype, or phenotype frequencies were observed between the MS patients and controls for any of the 14 TCRBV-gene polymorphisms studied. In light of the extensive linkage disequilibrium across the region studied, the saturating numbers of polymorphisms examined, and the direct sequence analysis of all BV genes in the region, these results suggest that it is unlikely that germ-line polymorphism in the TCRBV locus makes a major contribution to MS susceptibility.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

[Conservative surgery and radiation therapy in the treatment of operable breast cancer].

Forty-five patients with breast cancer were treated in our hospital by conservative surgery and radiation therapy from 1985 to 1994. There were 22 patients in stage I and 23 in stage II. All the patients were received breast-preserved operation including segmental resection and axillary node dissection. Routine postoperative irradiation was given to the patients with or without regional lymphatic melastasis. The indications of chemotherapy and endocrinotherapy were as same as those of Halsted's radical mastectomy. The duration of following-up was 3-5 years. The 5-year local recurrence was 8.8%. The 5-year OS was 94.1%, and DFS 94.1%.

Adenocarcinoma↗
PubMed1995

[An analysis of ocular manifestations in cases with tumors of accessory nasal sinuses].

The ocular manifestations of 60 cases with tumors of accessory nasal sinuses were reported. They were proptosis, impairment of ocular movement, diplopia, decrease or loss of visual acuity, ptosis, etc. Of them, 42 patients came to the ophthalmology department first. All the patients were diagnosed by computerized tomography (CT scan) and pathological findings. Operative treatment was applied in 48 cases. 32 cases had improvement in ocular symptoms. Particular attention was paid to the analysis of the causes of the patients, ocular symptoms and signs. They are due to the close anatomical relationship between accessory nasal sinuses and the orbit and optic nerve canal. CT scan is helpful to the early diagnosis of the disease.

Adolescent↗
PubMed1994

Expression of interleukin-2 receptor gamma chain on human neutrophils.

The interleukin-2 (IL-2) receptor gamma is an indispensable functional component of IL-2, IL-4, and IL-7 receptors, and thus, is denoted the common gamma chain, gamma c. The present study was undertaken to determine whether human polymorphonuclear neutrophils (PMNs) expressed gamma c chain. Reverse transcription-polymerase chain reaction and Northern blot analysis showed that fresh human PMN constitutively expressed a remarkable level of gamma c mRNA, which is of the size and intensity of that from the peripheral blood mononuclear cells (PBMCs). Granulocyte macrophage-colony stimulating factor, IL-2, and IL-8, which are known to activate PMN functions, failed to regulate the gamma c gene expression. Western blot analysis with a rabbit anti-gamma c polyclonal antibody identified 64-, 58-, and 50-kD gamma c bands in lysates from PMN, but only 64- and 58-kD bands from PBMCs. After the PMNs and PBMCs were treated with tunicamycin to prevent N-linked glycosylation, Western blot analysis detected a single 39-kD band, which is equal to the calculated molecular weight from the cloned cDNA. Thus, our results indicate that PMNs constitutively express high levels of gamma c and the three forms detected are caused by different glycosylation of a protein translated from a single mRNA species.

Base Sequence↗
PubMed1994

A multiple assay for vitamin D metabolites without high-performance liquid chromatography.

We describe a multiple assay of the three main vitamin D metabolites, 25OHD, 24,25(OH)2D, and 1,25(OH)2D, in 0.5 ml of serum, which does not require high-performance liquid chromatography. The assay involves extracting the serum with acetonitrile, separation and purification on a C-18/OH cartridge and a Sep-Pak silica cartridge, and quantitation using 1,25(OH)2D receptors from calf mammary gland for 1,25(OH)2D, and vitamin D binding protein for 25OHD and 24,25(OH)2D. For 25OHD, 24,25(OH)2D, and 1,25(OH)2D, the method is sensitive to 0.125 ng/tube, 0.025 ng/tube, and 0.5 pg/tube, with the B50 occurring at 1 ng/tube, 0.2 ng/tube, and 8 pg/tube, respectively. The coefficients of variation (SD/mean x 100%) intraassay (n = 8) were 5.4, 12.8, and 6.6% and interassay (n = 6) 12.3, 10.8, and 8.6%. The overall recovery was 80.4 +/- 5.5, 58.0 +/- 6.3, and 77.4 +/- 5.6% (mean +/- SD, n = 40). The validity of the assay was confirmed by dilution test, analytical recovery of added vitamin D metabolites, and comparison with a standard assay using HPLC. This assay offers a simple, rapid, and precise method with which to determine the three main vitamin D metabolites in small serum samples, so it should be particularly useful in studies of pediatrics or small animals.

Acetonitriles↗
PubMed1994

Level of human TCRBV3S1 (V beta 3) expression correlates with allelic polymorphism in the spacer region of the recombination signal sequence.

One of the causes of variations in the expressed human T cell receptor (TCR) BV (V beta) repertoire is genetic variation in the germline DNA. Herein evidence is provided that allelic polymorphism may affect recombination frequency for a specific V gene. Two alleles of the TCR BV3 differ only at a single nucleotide position (C/T) within the 23-bp spacer region of the recombination signal sequence. These alleles are associated with variable percentages of BV3 cells in the peripheral blood, as shown in families and in unrelated normal donors. Individuals homozygous for allele 2 have a mean of 8.1% BV3 cells, heterozygous individuals have a mean of 4.7% BV3 cells, and homozygotes for allele 1 have a mean of 1.2% BV3 cells in CD3+ CD4+ peripheral blood T cells. Since the correlation is tight in unrelated individuals and other genetic differences were not found in the vicinity of BV3, we suggest that the spacer region sequence itself modifies recombination efficiency. This allelic system provides an example of a novel mechanism by which cis-acting genetic elements may affect recombination in a natural in vivo system.

Alleles↗
PubMed1994

Molecular cloning of APRF, a novel IFN-stimulated gene factor 3 p91-related transcription factor involved in the gp130-mediated signaling pathway.

Acute-phase response factor (APRF) is a transcription factor that binds to the interleukin-6 (IL-6)-responsive elements identified in the promoters of various acute-phase protein genes. We report here the purification and cloning of APRF. APRF exhibits a 52.5% overall homology at the amino acid level with p91, a component of the interferon (IFN)-stimulated gene factor 3 complexes. The cloned APRF protein is tyrosine phosphorylated and translocated into the nucleus in response to IL-6, but not in response to IFN-gamma. Tyrosine phosphorylation was also observed in response to other cytokines, such as leukemia inhibitory factor, oncostatin M, and ciliary neurotrophic factor, whose receptors share the IL-6 receptor signal transducer gp130. In contrast, we observed that p91 is not tyrosine phosphorylated in response to IL-6. These results suggest that this novel p91-related protein may play a major role in the gp130-mediated signaling pathway and that selective activation of p91-related factors may explain the diversity of cellular responses to different cytokines.

Amino Acid Sequence↗
PubMed1994

Induction of IL-8 gene expression in human polymorphonuclear neutrophils by recombinant IL-2.

Induction of IL-8 gene expression was investigated in IL-2-stimulated circulating peripheral blood polymorphonuclear neutrophils (PMN). Brief exposure of normal PMN to human rIL-2 enhanced both transcriptional and translational expression of IL-8. The IL-8 mRNA was first detectable by 3 h, followed by a continuous maintenance of high mRNA levels up to 18 h. Maximal transcription was obtained with 1000 U/ml of IL-2, which achieved the level observed with known neutrophil-activating factors such as granulocyte macrophage-CSF and Candida albicans. The protein synthesis inhibitor, cycloheximide, had no detectable effect on levels of IL-8 mRNA expression in PMN incubated in medium alone; however, cycloheximide could selectively modulate IL-8 mRNA transcription in PMN, depending on the cytokine used. Cycloheximide did not affect or alter IL-8 mRNA induction in IL-2-treated PMN but abrogated it in granulocyte macrophage-CSF-treated PMN and super-induced the level of IL-8 mRNA in C. albicans-treated PMN. Of significance was the observation that IL-2 has no direct chemotactic effect on PMN, whereas the cell-free supernatants from IL-2-stimulated PMN show potent chemotaxis for freshly isolated PMN, which can be specifically blocked by anti-IL-8 Abs. These findings suggested that the induction of IL-8 gene expression in PMN by IL-2 may be involved in the recruitment of PMN into tissues during local IL-2 therapy in human cancer and in part contribute to tumor rejection.

Chemotaxis, Leukocyte↗
PubMed1994

Interleukin-2 prevention of apoptosis in human neutrophils.

Evidence is presented that interleukin (IL)-2 maintains viability of human polymorphonuclear cells (PMN) in culture by preventing these cells from undergoing programmed cell death (PCD) and induces the synthesis of new RNA and protein. Our laboratory has recently discovered that human PMN constitutively express IL-2 beta receptor and more importantly, PMN are able to respond functionally to IL-2 by enhanced growth inhibitory activity against an opportunistic fungal pathogen, Candida albicans. We now report that IL-2 was able to interfere with the PCD process and reduce the number of apoptotic PMN to < 40% in 72-h culture. Freshly isolated PMN usually underwent a time-dependent aging process and > 80% of PMN cultured in medium alone for 72 h showed morphologic features of PCD as depicted by hematoxylin and eosin staining as well as by electron microscopy. During the PCD process, untreated PMN not only exhibited condensed nuclear structure and decrease in cell size, but also displayed DNA fragmentation. DNA fragmentation in PMN was prevented by IL-2. Prevention of PCD by IL-2 was associated with an increase in new RNA and protein synthesis in PMN, which may reflect cytokine induction, such as tumor necrosis factor, as we have recently shown. Thus, our data expands our current understanding of PMN in that they may be an active component of the immune system, with a longer life-span when activated than expected.

Apoptosis↗
PubMed1994

Restoration of lytic function in a human natural killer cell line by gene transfection.

NK cells can recognize and lyse target cells without restriction by the MHC. The molecular interaction responsible for NK cell recognition is poorly understood. It has been frequently suggested that the loss of beta 2 integrin in immune competent cells may lead to dysfunction due to inadequate cell-cell interaction. We examined the role of lymphocyte functional adhesion molecule-1 in the function of a human natural killer leukemia cell line, YT-1. A mutant YT-1(-) cell subclone showed an absence of killing activity against a B lymphoma cell line, compared with that against a CD11a/CD18 positive parental cell line, YT-1(+) cells. We found that this loss of cytotoxicity was correlated with lack of surface expression of CD11a/CD18 molecules due to the mutation of the CD18 gene. Using gene transfer experiments, we provide strong evidence demonstrating that CD18 transfection to this mutant NK cell line, YT-1(-), restored the surface expression of CD11a/CD18, and this restoration was accompanied by reexpression of cytotoxic function.

Antigens, CD↗
PubMed1994

The extent of the human germline T-cell receptor V beta gene segment repertoire.

An assessment of the size of the human TCRBV gene segment repertoire based on the identification of TCRBV gene segments in genomic DNA was undertaken. PCR amplification from cloned and uncloned genomic DNA sources, nucleotide sequencing, Southern blot hybridization, and cosmid cloning were used to identify TCRBV gene segments in multiple unrelated individuals. The key advantages to this approach were: 1) TCRBV gene segments which are expressed only at very low levels in cDNA libraries were still detectable, and 2) it was possible to discriminate between alleles at the same locus vs products of different loci. A total of 63 unique TCRBV gene segments were identified and sequenced. Six of these TCRBV gene segments had not been previously described. Thirty-four cosmid clones containing 51 of the 63 identified TCRBV gene segments were isolated and screened for the presence of additional novel TCRBV subfamily members. These results, obtained by a variety of complementary approaches, indicate that the human TCRBV germline repertoire encodes at least 63 TCRBV gene segments of which 52 are functional. The availability of the majority of these TCRBV gene segments on cosmid clones should facilitate further investigation of germline TCRBV gene segment polymorphism and putative disease associations.

Base Sequence↗