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Biomedical subjects

G Pan

Publications and source records attributed to G Pan.

At least 73 records · Page 4Linked to original sources
PubMed1998

[Repair of large articular cartilage defect of hip with allograft of skull periosteum].

It is very difficult to repair large articular cartilage defect of the hip. From May 1990 to April 1994, 47 hips in 42 patients of large articuler cartilage defects were repaired by allograft of skull periosteum. Among them, 14 cases, whose femoral heads were grade. IV necrosis, were given deep iliac circumflex artery pedicled iliac bone graft simultaneously. The skull periosteum had been treated by low tempreturel (-40 degrees C) before and kept in Nitrogen (-196 degrees C) till use. During the operation, the skull periosteum was sutured tightly to the femoral head and sticked to the accetabulum by medical ZT glue. Thirty eight hips in 34 patients were followed up for 2-6 years with an average of 3.4 years. According to the hip postoperative criteria of Wu Zhi-kang, 25 cases were excellent, 5 cases very good, 3 cases good and 1 case fair. The mean score increased from 6.4 before operation to 15.8 after operation. The results showed, in compare with autograft of periosteum for biological resurface of large articular defect, this method is free of donor-site morbidity. Skull periosteum allograft was effective for the treatment of large articular cartilage defects in hip.

Adolescent↗
PubMed1998

[Risk of lung cancer among iron and steel workers in Anshan, China--case-control study].

A case-control interview study on 610 lung cancer patients and 959 controls was conducted among male workers in Anshan Iron-steel Complex. After adjusting for non-occupational risk factors, such as smoking, pulmonary disease, family history of cancer and the consumption of fruit, risks for lung cancer were significantly higher in workers engaged in smelting and rolling (OR = 1.5, 95% CI = 1.1-2.2), in the fire-resistant brick factory (OR = 2.9, 95% CI = 1.4-5.9), in general loading (OR = 2.5 95% CI = 1.0-6.1), and in coking (OR = 3.4, 95% CI = 1.4-8.5) for 15 or more years. Significant dose-response was observed for exposure to total dust and B[a]P, but not for specific chemical components of dust. The lung cancer risk increased 40% in iron and steel workers with long term occupational exposure.

Adult↗
PubMed1998

[The establishment of TNBS-induced experimental colitis].

OBJECTIVE: To explore the pathogenesis of inflammatory bowel disease (IBD) and to establish some indices monitoring the activity and severity of IBD. METHODS: A rat model of experimental colitis was induced by administration of the hapten 2, 4, 6-trinitrobenzenesulfonic acid (TNBS, 30 mg) in 50% ethanol 0.25 ml as the "barrier breaker". And it then recurs only after 10 mg TNBS administration. Inflammation was assessed by gross appearance using a grading scale and by histology. Myeloperoxidase(MPO) and superioxide dismutase(SOD) activities were also measured to evaluate the severity of inflammation. RESULTS: An acute inflammation with ulcers and neutrophil infiltration developed that evolved into a chronic inflammation with luminol narrowing and abundant fibrous connective tissue hypertrophy at 21 days. Crypt abcess were observed in some rats killed in 1 week. MPO activity was significantly elevated, while SOD decreased, in mucosa from all treated groups at all time intervals when macroscopic and microscopic mucosal injury was evident. CONCLUSIONS: These results indicate that this model affords an opportunity to study the pathogenesis of colonic inflammatory disease and may be used to evaluate new treatments potentially applicable to IBD in humans. In addition, MPO and SOD activities could be regarded as two markers which may evaluate the severity of colonic inflammation.

Animals↗
PubMed1998

[The effect of interleukin-1 beta interleukin-8 in the pathogenesis of experimental colitis and evaluation of interleukin-1 receptor antagonist therapy].

OBJECTIVE: To study the effect of interleukin-1 beta and interleukin-8 in the pathogenesis of colitis and evaluate the therapeutic effect of interleukin-1 receptor antagonist(IL-1ra). METHODS: A rat model of chronic experimental colitis was induced by administration of trinitrobenzenesulfonic acid (TNBS, 30 mg) in 50% ethanol 0.25 ml. IL-1ra was then administered intravenously with a dosage of 7 mg/kg at different times. Hydrocortisone (3 mg) i.v. administration was served as control. Tissue expression of IL-1 beta mRNA and IL-8 mRNA was then studied by in situ hybridization before and after IL-1ra administration. Histological examination and tissue myeloperoxidase (MPO) and superoxide dismutase (SOD) activities detection were also made to assess the severity of colitis. RESULTS: An acute inflammation with ulcers, neutrophil infiltration and crypt abscess developed that evolved into a chronic inflammation with abundant fibrous connective tissue hypertrophy at 21 days. And it then recurs only after 10 mg TNBS administration. Activities of MPO and SOD correlated with severity of inflammation. Expression of IL-1 beta mRNA was detected in macrophages in lamina propria and submucosa during the whole period of inflammation. It could be also present in epithelial cells in the 3rd day of colitis. While IL-8 mRNA expression appeared at the 3rd day, and disappeared at 21th day when colitis turned into chronic. After IL-1ra administration, the expression of these two interleukins could not be detected, accompanied with alleviation of histological manifestation, decrease of MPO activity and elevation of SOD activity. CONCLUSIONS: IL-1 beta and IL-8 were involved in the pathogenesis of colitis. IL-1ra has preventive and therapeutic effect to colitis.

Animals↗
PubMed1998

[p53 gene mutation in hepatocellular carcinoma].

OBJECTIVE: To study the relationship between mutation of p53 gene and hepatocellular carcinoma (HCC). METHOD: Sixty-five cases of HCC from Nanning prefecture of high aflatoxin (AFB1) exposure were studied by polymerase chain reaction and restrictive fragment length polymorphism (PCR-RFLP) analysis to examine the exon 7 of p53 gene in HCC. RESULT: 58.5% of the cases were found to show mutation at codon 249 of p53 gene; 63.6% for the HCCs with HBsAg negative, and 57.4% for those with HBsAg positive; 88.9% for those with metastasis, and 46.8% for those with no metastasis. The mutation rate of p53 gene was 10.0%, 55.2% and 80.8% in the well-, moderately- and poorly-differentiated HCC respectively. CONCLUSION: AFB1 is the most important agent for the mutation at the hot-spot, and hepatitis B virus is the synergistic risk factor. Further study indicated that the p53 gene mutation is correlated with the differentiation and the metastasis of HCC and may serve as an important prognostic factor.

Aflatoxin B1↗
PubMed1997

Interaction of elongation factors TFIIS and elongin A with a human RNA polymerase II holoenzyme capable of promoter-specific initiation and responsive to transcriptional activators.

Affinity chromatography on columns containing the immobilized monomeric transcriptional elongation factor TFIIS or the essential large subunit, Elongin A, of the trimeric elongation factor, Elongin, was used to purify a human RNA polymerase II holoenzyme from HeLa whole cell extract. This holoenzyme contained nearstoichiometric amounts of all the general transcription factors, TFIIB, TFIID (TBP + TAFIIs), TFIIE, TFIIF, and TFIIH, required to accurately initiate transcription in vitro at the adenovirus major late promoter. It behaved as a large complex, slightly smaller than 70 S ribosomes, during gel filtration chromatography, and contained nearly half the TFIID that was present in the extract used for the affinity chromatography. It also contained the cyclin-dependent kinase CDK8, a human homologue of the Saccharomyces cerevisiae holoenzyme subunit SRB10, and many other polypeptides. Efficient interaction of holoenzyme with TFIIS or Elongin A required only the amino-terminal region of either protein. These regions are similar in amino acid sequence but dispensable for TFIIS or Elongin to regulate elongation in vitro by highly purified RNA polymerase II. The transcriptional activators GAL4-VP16 and GAL4-Sp1 activated transcription in vitro by purified holoenzyme in the absence of any additional factors.

Amino Acid Sequence↗
PubMed1997

An antagonist decoy receptor and a death domain-containing receptor for TRAIL.

TRAIL, also called Apo2L, is a cytotoxic protein that induces apoptosis of many transformed cell lines but not of normal tissues, even though its death domain-containing receptor, DR4, is expressed on both cell types. An antagonist decoy receptor (designated as TRID for TRAIL receptor without an intracellular domain) that may explain the resistant phenotype of normal tissues was identified. TRID is a distinct gene product with an extracellular TRAIL-binding domain and a transmembrane domain but no intracellular signaling domain. TRID transcripts were detected in many normal human tissues but not in most cancer cell lines examined. Ectopic expression of TRID protected mammalian cells from TRAIL-induced apoptosis, which is consistent with a protective role. Another death domain-containing receptor for TRAIL (designated as death receptor-5), which preferentially engaged a FLICE (caspase-8)-related death protease, was also identified.

Amino Acid Sequence↗
PubMed1997

Test for qualitative interaction of clinical significance.

We generalize the problem of detecting qualitative interaction between treatments and subsets in a two treatment clinical trial to the more practical problem of detecting a qualitative interaction greater than a non-negative value d, corresponding to the minimal treatment difference of clinical significance. We develop a test based on simultaneous confidence intervals for the generalized problem under the assumption of normality. The proposed test is easy to implement, either by hand calculation or through the use of virtually any existing statistical software. We derive explicit power function for the proposed test and give examples to illustrate the procedures.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

The receptor for the cytotoxic ligand TRAIL.

TRAIL (also known as Apo-2L) is a member of the tumor necrosis factor (TNF) ligand family that rapidly induces apoptosis in a variety of transformed cell lines. The human receptor for TRAIL was found to be an undescribed member of the TNF-receptor family (designated death receptor-4, DR4) that contains a cytoplasmic "death domain" capable of engaging the cell suicide apparatus but not the nuclear factor kappa B pathway in the system studied. Unlike Fas, TNFR-1, and DR3, DR4 could not use FADD to transmit the death signal, suggesting the use of distinct proximal signaling machinery. Thus, the DR4-TRAIL axis defines another receptor-ligand pair involved in regulating cell suicide and tissue homeostasis.

Adaptor Proteins, Signal Transducing↗
PubMed1997

The C-terminal domain of RNA polymerase II couples mRNA processing to transcription.

Messenger RNA is produced by RNA polymerase II (pol II) transcription, followed by processing of the primary transcript. Transcription, splicing and cleavage-polyadenylation can occur independently in vitro, but we demonstrate here that these processes are intimately linked in vivo. We show that the carboxy-terminal domain (CTD) of the pol II large subunit is required for efficient RNA processing. Splicing, processing of the 3' end and termination of transcription downstream of the poly(A) site, are all inhibited by truncation of the CTD. We found that the cleavage-polyadenylation factors CPSF and CstF specifically bound to CTD affinity columns and copurified with pol II in a high-molecular-mass complex. Our demonstration of an association between the CTD and 3'-processing factors, considered together with reports of a similar interaction with splicing factors, suggests that an mRNA 'factory' exists which carries out coupled transcription, splicing and cleavage-polyadenylation of mRNA precursors.

Animals↗
PubMed1997

Relationship between Asbestos Exposures and 8-Hydroxydeoxyguanosine Levels in Leukocytic DNA of Workers at a Chinese Asbestos-material Plant.

The objective of the study was to evaluate the level of 8-hydroxydeoxyguanosine (8-OHdG) in DNA of peripheral-blood leukocytes as a biological marker of asbestos exposure and/or its fibrotic effects in an occupational population exposed to asbestos. The setting was a large-scale asbestos plant in China producing brake linings, asbestos rubber, and textile using chrysotile. From a base population of active and retired workers with various levels of cumulative exposure to asbestos and grades of asbestosis, 39 study subjects were randomly selected to reflect incremental grades of asbestosis based on Chinese diagnostic standards. They consisted of 19 "normal" (control) and ten "suspected" and ten "definite" asbestosis-grade subjects, group-matched for age and sex. Leukocytic DNA was extracted from 5-mL samples of peripheral blood and 8-OHdG level measured by high-pressure liquid chromatography. A cumulative asbestos exposure index (CEI) was calculated for each subject as the summed product of duration and level of asbestos exposure per job, incorporating a job-exposure matrix. Geometric mean 8-OHdG levels showed a positive gradient in relation to increasing grades of asbestosis (control: 1.78, suspected: 2.21, definite: 2.58), with a significant difference between the control and definite-asbestosis subgroups (p < 0.05). The 8-OHdG level of the two subgroups combined as one "asbestosis" group was significantly higher than that of the control group (control: 1.78, asbestosis: 2.39, p = 0.01). Further, 8-OHdG levels were moderately correlated with CEIs for all subjects (r = 0.35, p < 0.05) and with grades of asbestosis for all (r = 0.47, p < 0.01) and for male subjects (r = 0.43, p < 0.05). In multiple regression analyses, grade of asbestosis explained 27% of the total variation in 8-OHdG and was a better predictor than CEI or duration of exposure. Thus, the 8-OHdG level in leukocytic DNA is related to grade of asbestosis and to individual cumulative exposure and may serve as a biologic marker reflecting the status of oxidative DNA damage by asbestos.

Journal Article↗
PubMed1997

[GC-MS analysis of constituents of essential oils from stems of Ephedra sinica Stapf, E. intermedia Schrenk et C.A. Mey. and E. equisetina Bge].

The essential oils from the dried stems of Ephedra sinica, E. intermedia and E. equisetina were analyzed by GC-MS qualitatively and GC quantitatively. One hundred and twenty-seven constituents were identified, l-alpha-terpineol (31.64%) in E. sinica, 1,4-cineole (12.80%) in E. intermedia and hexadecanoic acid (26.22%) in E. equisetina being the main constituents.

Cycadopsida↗
PubMed1997

[Potential role of gut peptides in stress-induced colonic motor disorder].

OBJECTIVE: To explore the potential role of gut peptide in stress-induced colonic motor disorder. METHODS: In 9 conscious Wistar rats pre-equipped with strain-gauge transducers on ascending and descending colon, colonic motility was recorded before, during and after stress. And colonic transit was evaluated by instilling Cr into the cecum through chronically implanted cannula in each group of 16 rats with or without stress, and then calculating the geometric center (GC) of radioactivity. The contents of VIP, SP, NT, SST, MOT and Leu-ENK in plasma, colonic mucosa and muscle layer were assessed in 16 stressed and 16 control rats. Exogenous peptides (VIP, SP, SST, NT) were intravenously administered in 9 rats to determine the colonic motor response. Also, the effects of peptides on colonic circular muscle strips were investigated. RESULTS: Motor activity was increased after stress, whereas colonic transit was delayed. In the stressed rats, plasma levels of VIP and Leu-ENK were higher than those in controls. The content of Leu-ENK in muscle tissue decreased. Both in vivo and in vitro studies showed that SP and NT excited, whereas VIP and SST inhibited colonic motor activity. CONCLUSION: Release of certain peptides is altered by stress. Increased release of ENK and VIP may be involved in stress-induced colonic motor disorder and in the regulation of "stress hormone" release.

Animals↗
PubMed1996

Characterization of the interaction between the acidic activation domain of VP16 and the RNA polymerase II initiation factor TFIIB.

Contact between a transcriptional activator and one or more components of the RNA polymerase II transcription initiation machinery is generally believed important for activators to function. Several different molecular targets have been suggested for direct contact by herpes simplex virus virion protein VP16, including the general initiation factor TFIIB. In this report we have used several strategies to critically assess this interaction between VP16 and TFIIB. Affinity columns of VP16 bound TFIIB activity from HeLa cell extracts and the binding was reduced by mutations in the activation domain of VP16. In assays of direct binding, VP16 bound recombinant human TFIIB but not Drosophila or yeast TFIIB. Unlike binding from an extract, however, we found that the interaction between VP16 and recombinant human TFIIB was not affected by mutations in VP16 that reduce transactivation. Point mutations within human TFIIB that reduce transactivation by VP16 have been shown to reduce VP16 binding, but we show here that these same mutations critically affect both the important TBP-TFIIB interaction and the ability of TFIIB to support activator-independent basal transcription in vitro. Taken together our results suggest more evidence is needed to support the notion that TFIIB is a functionally important target for the activator VP16.

Animals↗
PubMed1996

The syndrome of lung hemorrhage and nephritis is usually an ANCA-associated condition.

BACKGROUND: In the absence of evidence of arteritis or Wegener's granulomatosis, the syndrome of lung hemorrhage and nephritis has been commonly associated with anti-glomerular basement membrane (GBM) antibodies. However, it has been increasingly recognized that many cases are associated with antineutrophil cytoplasmic antibodies (ANCAs). OBJECTIVE: To review available clinical and pathologic findings to determine the diseases accounting for lung hemorrhage and nephritis. METHODS: We studied the records of 750 patients from whom serum samples were sent to our laboratory for anti-GBM antibody assays between 1981 and 1993 and found 88 patients with evidence of lung hemorrhage and nephritis. Serum samples were retested, using current methods, for anti-GBM antibodies (against noncollagenous 1 domain of the alpha 3 chain of type IV collagen) and for antibodies to proteinase 3 and myeloperoxidase--the two types of ANCA of diagnostic value. RESULTS: Of 88 patients with evidence of lung hemorrhage and nephritis, 48 had ANCAs, six had anti-GBM antibodies, and seven had both. In 48 patients with ANCAs, the pathologic findings that accounted for the pulmonary renal syndrome were pauci-immune necrotizing and crescentic glomerulonephritis and pulmonary capillaritis. Only eight had convincing evidence (during life) of Wegener's granulomatosis and only one other had documented arteritis. In 27 patients without ANCAs or anti-GBM antibodies, a variety of unrelated renal and pulmonary diseases were found. CONCLUSIONS: The largest group of patients who present with the syndrome of lung hemorrhage and nephritis have ANCAs and not anti-GMB antibodies. Appropriate tests for antibodies to proteinase 3, antibodies to myeloperoxidase, and anti-GBM antibodies provide reliable guides for making a diagnosis in patients with this pulmonary renal syndrome.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1996

Subset selection with additional order information.

Traditional subset selection procedures were developed without assuming any order information about the response variable. However, in some applications there is additional, even though incomplete, order information about the treatment effects at increasing treatment levels. One important example is the up-then-down umbrella ordering with an unknown peak. This type of additional order information is utilized explicitly in this paper to construct subset selection procedures for several settings studied in the literature where only order restricted tests are known to exist. This paper also proposes a straightforward algorithm to compute the isotonic regression with respect to umbrella orderings, which can be used to carry out the proposed procedures. Examples are given to illustrate the procedures and algorithm.

Algorithms↗
PubMed1996

[Diagnosis of chylous ascites with oral administration of 13C-palmitic acid].

12 cases of chylous ascites in PUMC hospital in the recent 30 years were analysed. The etiology of this disease includes non-traumatic (83.3%) and traumatic (16.7%) causes. All the patients received isotope examination or lymphangiography, but only in 8 patients the site of the lesion was found. As these two kinds of examination can only show the lesions in the right and left lumbar lymph trunks, cisterna chyli and throacic duct but not the intestinal lymph truck, the authors set up a method by administering orally 13C-palmitic acid to detect the lesion of intestinal lymph trunk. Palmitic acid is a long-chain fatty acid, which enters directly into the intestinal lymph trunk after absorption. Palmitic acid labelled with 13C could be detected in the ascitic fluid if there is a leak from intestinal lymph trunk. This new method was used to examine a patients who had negative results with isotope examination and lymphangiography; 13C could be detected in the ascitic fluid 30 minutes after oral administration but not in exhaled air. It can be concluded that cyhle leaked into the peritoneal cavity from the intestinal lymph trunk. This method is also of help to determine the possible site of leakage and the degree of obstruction, so it is quite useful for the diagnosis of chylous ascities.

Administration, Oral↗