PubMed Health⌕ Search

Biomedical subjects

Z Shi

Publications and source records attributed to Z Shi.

At least 109 records · Page 6Linked to original sources
PubMed1998

Kinetic alterations of angiotensin-II and nitric oxide in radiation pulmonary fibrosis.

We studied the kinetic alterations of angiotensin-II (A-II) and nitric oxide (NO) in radiation pulmonary fibrosis (RPF) to determine the roles of these two types of vasoactive substances in the pathogenesis of RPF. We irradiated the right hemithorax of male Wistar rats with single doses of 0, 15, and 30 Gy of 60Co gamma rays and we examined the lung parenchyma at 1, 3, 5, and 7 months following the radiation. The rats were killed at the stated intervals and samples were obtained from the right lung. We measured types I and III procollagen mRNA by in situ hybridization and demonstrated the synthesis and distribution of A-II in the pulmonary tissue by immunohistochemistry. The formation and kinetic alterations of types I and III collagen were analyzed under polarized light microscope using Sirius Red stain. The hydroxyproline (Hyp) content was measured in the pulmonary tissue after digestion with HCl. A-II radiation immunoactivity (RIA) was assayed in pulmonary tissue homogenate. Pulmonary NO content, NO synthase (NOS), and the angiotensin converting enzyme (ACE) activities were also measured. Our results showed that types I and III collagen genes began to be expressed 1 month after irradiation. Type I collagen gene increased significantly, reaching its peak 3 months after irradiation. As the irradiation dosage was increased from 15 to 30 Gy, the type I collagen gene content increased significantly, while type III significantly decreased. The Hyp content increased with the passage of time after irradiation. Pulmonary A-II RIA increased significantly with the dose of irradiation and was chiefly produced by fibroblasts and macrophages in the interstitium, bronchiolar epithelium, and the anteriolar wall. Pulmonary NO and NOS activities decreased following irradiation. One month following irradiation, the expression of the type I collagen gene begins to increase, with a significant increase in both Hyp and type I collagen 3 months after irradiation. The histogenesis of RPF may be related to A-II. The interstitial cells, the bronchiolar epithelium, and the arteriolar wall can produce A-II and need not pass through the ACE pathway. Our results suggest that the A-II increase and NO decrease may have a role in the pathogenesis of RPF.

Angiotensin II↗
PubMed1998

[Application of chromosome painting to analysis of structural aberration in five cases].

OBJECTIVE: This article reports that competitive hybridization using entire chromosome specific libraries as probe and human genomic DNA as the competitor allows intense and specific fluorescent staining of human chromosome in metaphase. This general approach is called "chromosome painting". METHODS: The probes comprising chromosomes 2, 5, 6, 7, 13, 14, X specific libraries were used to analyse five cases which had been suspected of subtle translocation and deletion in karyotype analysis by G-banding of metaphase cells. The authors selected entire chromosome-specific DNA libraries hybridizing with the five cases. Unlabeled human genomic DNA was used to inhibit the hybridization of sequences in the library that bind to multiple chromosome. RESULTS: The target chromosome was made at least 20 times brighter parunit length than the others. Translocations and deletions were detected clearly in metaphase and were consistent with G-banding. However, the result was clearer and the detection easier, compared with G-banding. CONCLUSION: Chromosome painting is very powerful for identification of chromosome structural aberrations. Translocation and deletion involving these chromosomes can be strikingly visualized. The hybridization intensity and specificity are such that even very small portions of the involved chromosome can be detected. This technique is especially useful in settings where high-quality banding is difficult.

Adult↗
PubMed1997

Overexpression of adenovirus-encoded transgenes from the cytomegalovirus immediate early promoter in irradiated tumor cells.

Efficient expression of therapeutic genes in irradiated tumor cells would facilitate the conversion of a malignant tumor nodule into a cancer vaccine in situ. We reported previously that transgene expression from an adenoviral vector could be markedly enhanced by treating transduced tumor cells with butyrate. In this study, we demonstrated that a similar butyrate effect could be achieved in irradiated tumor cells. In addition, irradiating cells at doses of 2-40 Gy prior to transduction could also amplify recombinant adenoviral transgene products in a cell-type-specific manner. This suggests that adenovirus-mediated gene therapy, radiation therapy, and butyrate-mediated cancer therapy may potentially be formulated into one synergistic protocol for cancer treatment.

Adenoviridae↗
PubMed1997

Strain-specific differences in mouse hepatic wound healing are mediated by divergent T helper cytokine responses.

Hepatic fibrosis represents the generalized response of the liver to injury and is characterized by excessive deposition of extracellular matrix. The cellular basis of this process is complex and involves interplay of many factors, of which cytokines are prominent. We have identified divergent fibrosing responses to injury among mouse strains and taken advantage of these differences to examine and contrast T helper (Th)-derived cytokines during fibrogenesis. Liver injury was induced with carbon tetrachloride, fibrosis was quantitated, and Th1/Th2 cytokine mRNAs measured. Liver injury in BALB/c mice resulted in severe fibrosis, whereas C57BL/6 mice developed comparatively minimal fibrosis. Fibrogenesis was significantly modified in T and B cell-deficient BALB/c and C57BL/6 severe combined immunodeficient (SCID) mice compared with wild-type counterparts, suggesting a role of Th subsets. Fibrogenic BALB/c mice exhibited a Th2 response during the wounding response, whereas C57BL/6 mice displayed a Th1 response, suggesting that hepatic fibrosis is influenced by different T helper subsets. Moreover, mice lacking interferon gamma, which default to the Th2 cytokine pathway, exhibited more pronounced fibrotic lesions than did wild-type animals. Finally, shifting of the Th2 response toward a Th1 response by treatment with neutralizing anti-interleukin 4 or with interferon gamma itself ameliorated fibrosis in BALB/c mice. These data support a role for immune modulation of hepatic fibrosis and suggest that Th cytokine subsets can modulate the fibrotic response to injury.

Animals↗
PubMed1997

Characterization of colorectal-cancer-related cDNA clones obtained by subtractive hybridization screening.

In an attempt to seek out new factors that are related to colorectal carcinogenesis at the molecular level, subtractive hybridization between cDNA of normal mucosal tissues and mRNA of colorectal carcinoma tissues was performed. Subsequent screenings of the cDNA libraries, constructed from normal mucosal tissues, using the "subtractive probes" generated a total of 46 clones that were expressed in normal mucosa but were either expressed at a significantly reduced level or not expressed at all in cancer tissues. Partial nucleotide sequences of all of these cDNA clones were determined, and sequence homology analyses were performed with the Genbank database. Of the 46 cDNA samples, 44 contained substantial sequence homologies with 32 immunoglobulin gene fragments, a helix-loop-helix basic phosphoprotein gene, an acidic ribosomal phosphoprotein P2 gene, a BLR1 gene for Burkitt's lymphoma receptor 1 gene, D5S419 DNA segment containing (C-A) repeats, a glucokinase (GCK) gene, a Na+, K+-ATPase alpha-subunit gene, a histocompatibility system HLA-DR heavy-chain gene, a dystrophic gene, a mucin (MUC2) gene, a mu-glutathione S-transferase gene, a Menkes disease protein gene, and a 40-kDa keratin intermediate filament precursor gene. The remaining two cDNA clones (now registered under GenBank accession numbers U17714 and U20428) showed few (less than 60%) sequence homologies with any known sequences in the GenBank database and, therefore, may represent novel genes whose expression was down-regulated in human colorectal carcinomas. The possible clinical significance of these findings and the involvement of these two genes in the carcinogenesis of colorectal as well as other cancers are being investigated.

Base Sequence↗
PubMed1997

[Expression of human papillomavirus 16, 18 E6 protein of cervical squamous cell carcinoma].

OBJECTIVE: To investigate the expression of human papillomavirus (HPV) 16, 18 E6 protein of cervical squamous cell carcinoma and to assess the practical value of HPV 16, 18 E6 antibody. METHODS: Immunohistochemistry SP method was used to examine HPV 16, 18 E6 protein expression in 40 cases of squamous cell carcinoma of uterine cerivx, 30 cases of chronic cervicitis and 30 cases of normal cervical epidermal tissue. RESULTS: 27/40 carcinoma cases and 1/30 chronic cervicitis showed positive staining. None of the normal epithelium specimens gave positive results. The difference between malignant and benign groups was significant. CONCLUSION: A close relation between high risk HPV 16, 18 E6 antibody could be a good indicator for HPV 16, 18 infection and early diagnosis of cervical carcinoma.

Carcinoma, Squamous Cell↗
PubMed1997

[Comparison of changes of bone mass, parathyroid hormone and calcitonin between two animal models of bone loss].

The changes in bone mass, blood parathyroid hormone (PTH) and calcitonin (CT) between rats suspended for 14 and 21 days, simulated weightlessness, and rats ovariectomized (OVX) for 30 and 60 days were observed. The results revealed that mineral density of T6 and L3 was significantly increased in rats suspended for 14 days. T6 mineral density was also significantly increased in rats suspended for 21 days, but L3 mineral density was significantly decreased. T6 mineral density had no change in OVX rats, but L3 mineral density was significantly decreased in them both for 30 and 60 days. Mineral content at proximal 1/3 of femur shaft was significantly decreased in rats suspended for 14 and 21 days, and in rats OVX for 60 days. Bone biomechanical properties of suspended rats were more seriously deteriorated than that in OVX rats. There was no change in blood PTH, but CT was significantly increased in rats suspended for 14 and 21 days. Blood PTH and CT were significantly decreased in rats OVX for 30 and 60 days. The results indicate that the mineral redistribution and bone loss are presented in trabecular bone of suspended rats, but not in OVX rats. The deterioration of bone quality was more seriously in suspended rats than that in OVX rats. Both the cortical and trabecular bone in the two models were affected.

Animals↗
PubMed1997

[The effect of epithelium on inhibition of histamine-induced contraction of guinea-pig isolated trachea by potassium channel opener Rp 52891].

To evaluate whether the relaxant effect of Rp 52891 on isolated normal or sensitized guinea-pigs trachea is influenced by the removal of airway epithelium, twenty-four normal and sensitized guinea-pigs were randomly divided into two groups: epithelium-intact trachea and epithelium-denuded trachea. The effect of Rp 52891 on contraction elicited by histamine in epithelium-intact and epithelium-denuded trachea was investigated, and it was compared with that of aminophylline or isoprenaline. The results revealed that there was no significant difference in histamine-induced contractile response between normal and sensitized isolated trachea. The inhibitory effect of Rp 52891 on the contractile response of histamine was significantly reduced by removing the epithelium but that of aminophylline or isoprenaline was not changed. These results suggested that Rp 52891 may directly relax the airway smooth muscle of guinea-pigs in vitro, the epithelium of guinea-pigs trachea may modulate the relaxant effect of Rp 52891.

Aminophylline↗
PubMed1997

Clinical therapeutic effect of drug-separated moxibustion on chronic diarrhea and its immunologic mechanisms.

In the present paper it was reported that 24 cases of ulcerative colitis and 23 cases of chronic colitis were treated by drug-separated moxibustion and the total effective rates were 95.83% and 95.65% respectively, which were markedly superior to that of western medicine group. Observation in 15 cases of ulcerative colitis showed that drug-separated moxibustion could inhibit humoral immunity and elevate cellular immune function. The therapy possibly regulated the abnormal ratio of T-lymphocyte subgroups and corrected the abnormal state of autoimmunity of patients, so that pathological changes of intestinal mucosa were corrected effectively.

Adult↗
PubMed1997

[Effect of recombinant bactericidal/permeability-increasing protein on pulmonary cytokine mRNA expression in rats following hemorrhage and resuscitation].

To determine the possible mechanisms underlying beneficial effect of recombinant bactericidal/permeability-increasing protein (rBPI) on acute lung injury response to blood loss, we used reverse transcription polymerase chain reaction to measure pulmonary tumor necrosis factor (TNF), interleukin 6 (IL-6) mRNA expression in a rat model of prolonged hemorrhagic shock (4.00 kPa, 180 min) followed by adequate resuscitation. The results showed that systemic plasma endotoxin concentrations elevated rapidly after a 180-min hemorrhagic insult (P < 0.05), and TNF, IL-6 mRNA expression in the lung were significantly increased at 2, 8 hours after resuscitation respectively. However, treatment with rBPI resulted in almost neutralization of plasma endotoxin values, remarkable reduction of TNF, IL-6 mRNA levels following hemorrhage/resuscitation. Also, it was found that rBPI administration markedly blunted the increase in pulmonary Evans blue dye extravasation, concomitant with a significant decrease in lung myeloperoxidase activity compared with the control group (P < 0.05-0.01). These data suggest that local proinflammatory cytokine mRNA expression associated with gut origin endotoxemia may be an important mechanism contributing to the development of hemorrhage-induced lung injury. Treatment with rBPI is effective in inhibiting marked TNF, IL-6 mRNA expression and ameliorating acute lung injury secondary to severe hemorrhagic shock.

Animals↗
PubMed1997

[Chest CT and its assessment of resectability in lung cancer].

OBJECTIVE: To evaluate chest CT and its relation to possible surgical resection in lung cancer patients. METHODS: Ninty-five patients who were diagnosed and confirmed as having lung cancers by surgery and pathology were divided into three groups: (1) Radical resection group; (2) Palliative resection group and (3) Thoractomy group. The diameter of the tumor, the proximity to mediastinum and/or the hilum and the invasion of their lymph nodes were measured. Meanwhile, the changes in the mediastinum and thoracic cavity on the chest CT were noted in these three groups. RESULTS: The diameter of the tumor in each group was 4.10 +/- 1.75, 3.90 +/- 1.20, 5.20 +/- 3.66 (cm, mean +/- s, P > 0.05). The proximity to the mediastinum and/or the hilum and the invasion of their lymph nodes was 2.68 +/- 1.60, 4.02 +/- 1.56, 4.85 +/- 3.28 (cm, mean +/- s, P < 0.01, P < 0.05). The characteristic change in the thoractomy group is deformity in the lymph nodes in the mediastinum and hilum. CONCLUSION: There is no obvious relation between the diameter of the lumg tumor and surgical resection, but the proximity to the mediastinum and/or the hilum and the invasion of their lymph nodes is an important factor. It is possible to perform a radical resection when its contact is less than 2.68 +/- 1.60 cm. Obvious deformity of the mediastinal structures and the hilum is a contraindication for lung cancer surgery.

Adenocarcinoma↗
PubMed1997

[Matched case control study for investigating of the association between psychosocial factors and TMJDS].

A 1:1 matched case control study was carried out in 81 cases with temporomandibular joint dysfunction syndrome (TMJDS) who came to a TMJ clinic of a tertiary dental centre for help and 81 controls without TMJDS to investigate the association between psychosocial factors and TMJDS. The results showed that anxiety and depression might be one of the risk factors of TMJDS. Trait anxiety and Eysenck's neuroticism might be the inherent personality factor of anxiety, and the later might be the basis of depression. Life events and social support might be the external factors of TMJDS.

Adolescent↗
PubMed1997

Changes in bone noncollagenous proteins and bone mineral loss in lumbar vertebrae of tail-suspended rats.

The purpose of the study is to clarify whether the noncollagenous proteins play a role in bone mineral loss and whether the quality of osteocalcin (OC) is deteriorated in simulated weightlessness. Noncollagenous proteins, such as OC and albumin, have been shown to be effective in promoting bone mineralization. In this study, the contents of OC, albumin, and mineral in the third lumbar vertebra (L3) were determined in rats suspended by tail for 21 days. The concentration of serum-immunoreactive osteocalcin (irOC) were also measured before and after adsorption to hydroxylapatite. The results showed that the contents of mineral, osteocalcin, and albumin in L3 were significantly decreased in suspended rats. The concentration of serum irOC and serum irOC with a high affinity to hydroxylapatite (irOCbound) were significantly decreased, but the low affinity (irOCfree) remained unaffected. The data suggest that the mineral loss in L3 of suspended rats is related to the decreased contents of osteocalcin, and albumin in bone mass. The incomplete gamma-carboxylation of osteocalcin in suspended rats is also one of the important causes of bone loss.

Albumins↗
PubMed1997

Screening and identification of down-regulated genes in colorectal carcinoma by subtractive hybridization: a method to identify putative tumor suppressor genes.

OBJECTIVE: To search for new putative tumor suppressor genes in colorectal carcinoma. METHODS: Subtractive hybridization technologies were applied to screen and select genes, the expression of which was down-regulated in colorectal carcinoma. mRNAs uniquely expressed in normal cells but not in colorectal carcinoma were recovered as cDNA (sub-cDNA) after two rounds of subtractive hybridization with mRNA prepared from colorectal carcinoma. The sub-cDNAs were then used as probes to screen a normal human colon cDNA library constructed in lambda-Zap II phage. The DNAs of positive clones were in vivo excised, and partial DNA sequences were analyzed and compared with DNA sequence database Genbank. RESULTS: A total of 46 different clones with an average of about 1 kilobases in transcript size was recovered. Among these 46 down-regulated genes in colorectal carcinoma were genes encoding immunoglobulin (n = 32), 40-kDa keratin intermediate filamentous protein or IFP (n = 1), major histocompatibility complex-related protein (n = 1), unrelated structural proteins (n = 10) and gene products yet to be identified (n = 2). RNA dotblot hybridizations confirmed that all 46 clones contained genes that were down-regulated and have not been reported before in colorectal carcinoma. CONCLUSION: The results of this study suggested that the 46 clones were down-regulated in colorectal carcinoma, they should be further studied as new putative tumor suppressor genes and could be used as new tumor markers of colorectal carcinoma.

Colorectal Neoplasms↗
PubMed1997

Oxygen free radical injury and its relation to bacterial and endotoxin translocation after delayed fluid resuscitation: clinical and experimental study.

OBJECTIVE: To examine whether there is generation of oxygen free radicals (OFR) and lipid peroxidation of cell membrane after volume replacement for burn shock, and to study the relationship between OFR injury and enterogenous endotoxemia. METHODS: Forty-seven burn patients were involved in this study. Among them, 18 had delayed fluid resuscitation (DR) and the others had early fluid resuscitation (ER) within 6 hours postburn. Sixty-six gnotobiotic rats were used in a collaborating experiment as burn models. They were divided into 4 groups: sham injury (n = 6), early resuscitation (n = 24), late resuscitation (n = 24) and vitamins E and C treatment group (n = 12). All the rats, except those in the sham injury group, were inflicted with 40% total body surface area (TBSA) third-degree burns. OFR was determined in the blood of patients with electron spin resonance (ESR). S/W ratio and tau c values of patients' erythrocytes were measured with ESR spectrometer. Blood superoxide dismutase (SOD) and glutathione peroxidase (GSHPx) activities, malondialdehyde contents and plasma endotoxin levels were assayed. Rats were sacrificed at the 12th, 24th, 48th and 72nd hour after injury. Plasma endotoxin levels, mucosal SOD, GSHPx and malondialdehyde (MDA), as well as diamine oxidase activity of ileum were determined. Cultures of mesenteric lymph nodes (MLN), liver, spleen, heart, lung, kidney and blood were done. RESULTS: A significant increase in blood OFR contents and plasma MDA, and a significant decline in blood SOD and GSHPx were found after resuscitation in DR group as compared with those in ER group. Both strong to weak spectra component (S/W) ratio and tau c value were higher in DR group in contrast with those in ER group. Higher elevation in plasma endotoxin level in DR group was seen. In DR group, plasma MDA content was correlated with S/W ratio, tau c value and plasma endotoxin level. In rats, the level of mucosal MDA, plasma endotoxin and incidence of bacterial translocation (BT) were significantly higher. Mucosal SOD, GSHPx and diamine oxidase (DAO) activity were significantly lower in DR group as compared with those in ER group. In DR group, mucosal MDA content was negatively correlated with mucosal DAO activity, while the latter was negatively correlated with BT. After treatment with vitamins E and C, mucosal MDA content decreased, plasma endotoxin and BT significantly declined and mucosal DAO heightened. CONCLUSIONS: Tissue reperfusion might induce the production of OFR, resulting in lipid peroxidation injury, especially to intestinal mucosa, and resulting in disruption of mucosal barrier function followed by endotoxemia and BT.

Adolescent↗
PubMed1997

[Effects of TIMP-2 gene transfection on biological behaviors of a metastatic human lung carcinoma cell line].

OBJECTIVES: To explore the suppressive effects of tissue inhibitor of metalloproteinase 2 (TIMP-2) on malignant phenotype of human carcinoma cells and to evaluate its potential application in cancer gene therapy. METHODS: A man malian expression vector containing TIMP-2 cDNA was constructed and transfected into a metastatic human lung carcinoma cell line PG. In vitro and in vivo tests such as Northern blotting, immunohistochemistry as well as x enografting in nude mice experiment were used to analyse expression levels of TIMPs and MMPs, in vitro and in vivo behaviors of the tumor cells before and after the gene transfection. RESULTS: After transfection, the TIMP-2 mRNA expression was upregulated significantly. Changes, in some malignant phenotypes of the transfectants were seen. For instance, the abilities of in vitro invasion through Matrigel, colony formation on soft agar, tumorigenecity as well as spontaneous metastasis in nude mice were remarkably decreased. Immunohistochemical staining and in situ hybrydization showed that MMP2, MMP9, TIMP-1 and TIMP-2 were expressed by both tumor cells and stromal cells, with stronger staining at the site of tumor invasion. CONCLUSION: Up-regulation of TIMP-2 in tumor cells could suppress their expression of malignant phenotype and could be used for cancer therapy.

Animals↗