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Biomedical subjects

Q Shi

Publications and source records attributed to Q Shi.

At least 145 records · Page 8Linked to original sources
PubMed1998

Suppression of tumorigenicity and metastasis of human renal carcinoma cells by infection with retroviral vectors harboring the murine inducible nitric oxide synthase gene.

The purpose of this study was to determine whether retrovirus-mediated transfer of the murine macrophage inducible nitric oxide synthase (iNOS) gene can inhibit tumorigenicity and metastasis of human renal cancer cells. Retroviral vectors encoding murine macrophage iNOS were constructed in the pLXSN retroviral vector with the iNOS gene under the control of a long terminal repeat promoter and a neomycin resistance gene under the control of an internal simian virus 40 promoter. Highly metastatic human renal carcinoma SN12PM6 cells were infected with control or iNOS retrovirus. Expression of iNOS was confirmed by Northern and Western blot analyses, and expression of the functional iNOS protein, i.e., production of nitric oxide (NO), was determined by measuring nitrite accumulation in culture supernatants. Noninfected or control cells produced large orthotopic tumors in the kidney of nude mice and a larger number of experimental lung metastases, whereas iNOS-infected cells produced small tumors in the kidneys and few to no lung metastases. The data indicate that the infection of human renal cancer cells by retroviruses harboring the murine iNOS gene can induce the production of high levels of NO, which is associated with autocytotoxicity, suppression of tumorigenicity, and abrogation of metastasis.

Animals↗
PubMed1998

[Determination of the polymorphism of DXS102 locus and its application in gene diagnosis].

OBJECTIVE: To determine the polymorphism of DXS102 and use it in gene diagnosis in hemophilia B. METHODS: Amp-FLP and linkage analysis on 234 chromosomes. RESULTS: Eight alleles were found at DXS102 locus. The number of AC dinucleotide repeats ranged from 13 to 21. And the observed heterozygosity, calculated heterozygosity and polymorphism information content(PIC) were 0.87, 0.80 and 0.80, respectively. It was noted that the difference of the allele frequencies of DXS102 in Chinese and European populations was significant. By using the linkage analysis of the DXS102 locus, a family with a hemophilia B patient receiving gene therapy in 1994 was analyzed and a carrier in that family was then detected. CONCLUSION: The polymorphism of DXS102 locus reveals significant difference between Chinese and European populations. DXS102 locus can be used as a promising marker for gene diagnosis in hemophilia B family.

Chromosome Mapping↗
PubMed1998

Neglect and constructive disorder.

A 61 year-old right handed man, who suffered from right cerebral infarction with evidences of visual-spatial neglect and constructive disorder, was reported. When copying simple geometric designs, he omitted to copy figures on the left side of the page; he tended to bisect the line to the right of the line's real center; after memorizing the familiar pictures he mainly mentioned the pictures on the right side of the page; when copying the "Rey Complex" he also ignored the structures on the left side. The relations of the neglect and construction disorder are discussed.

Apraxias↗
PubMed1998

Apparent blood stream origin of endothelial and smooth muscle cells in the neointima of long, impervious carotid-femoral grafts in the dog.

The purpose of this study was to determine whether endothelial and smooth muscle cells originating from the blood stream contribute to the endothelialization of impervious, small-caliber, long Dacron grafts used as extraanatomical bypasses in dogs. We implanted silicone-rubber-coated, permanently impervious grafts 64 to 77 cm long and 6 mm in diameter, made of externally supported knitted Dacron as unilateral carotid-femoral bypasses with distal femoral arteriovenous fistulae in 10 dogs for 3 months; sides were alternated between cases. Subjects received 162 mg/day of aspirin, and its effectiveness on platelet aggregation (PA) was evaluated and expressed as a PA score. Graft healing was studied by stereomicroscopy with silver nitrate staining, by light microscopy with hematoxylin-eosin and immunocytochemical staining for endothelial and smooth muscle cells, and by scanning and transmission electron microscopy. Five grafts were patent for 3 months and could be included in the healing study; the five occluded grafts thrombosed within 14 days. Although there was no transinterstitial tissue ingrowth from perigraft tissues into the impervious Dacron grafts, scattered islands of endothelial cells were conclusively demonstrated on graft flow surfaces 3 months after implantation. Average endothelial-like cell coverage of the flow surfaces was 15.6% +/- 3.8%, and alpha-actin-positive smooth muscle cells and microvessels were found beneath some of the endothelial islands. These findings suggest that blood stream-derived endothelial and smooth muscle cells play a role in the healing of the inner wall of Dacron grafts in the dog.

Animals↗
PubMed1998

Early flow surface endothelialization before microvessel ingrowth in accelerated graft healing, with BrdU identification of cellular proliferation.

The purpose of this report was to determine if flow surface endothelialization could precede microvessel ingrowth from the perigraft area in porous Dacron grafts, by using an accelerated graft healing model with short implant periods. Dacron grafts were implanted in the abdominal aorta of 22 dogs and wrapped in autogenous inferior vena cava (IVC), which provided excellent conditions for extramural angiogenesis, microvessel development, and ingrowth toward the graft. Retrieval times were 7 days (n = 4), 8 days (n = 5), 9 days (n = 4), 10 days (n = 3), 11 days (n = 4) and 12 days (n = 3) postoperatively. Graft surfaces were evaluated for thrombus coverage, cell coverage, and the number of micro-ostia. Components and cellular types in the graft wall and on the surface were studied and characterized with H&E, histochemical, and immunocytochemical staining. BrdU labeling was also used, to identify the areas where cells were actively proliferating. All grafts were patent. Although the degree of IVC/graft attachment varied, isolated islands of endothelial-like cells were found at the midgraft areas at each time period, and immunocytochemically confirmed as endothelial cells. There were two healing patterns: (1) surface endothelialization before microvessel/tissue ingrowth from the perigraft areas, and (2) surface endothelialization with full wall microvessel and tissue presence. Surface endothelialization was observed before perigraft tissue ingrowth, indicating that fallout healing is an independent source of endothelialization for porous grafts.

Animals↗
PubMed1998

The effect of flow shear stress on endothelialization of impervious Dacron grafts from circulating cells in the arterial and venous systems of the same dog.

The purpose of this report was to study effects of shear force and hemodynamic conditions that influence fallout healing in the arterial and venous systems of the same dog. Knitted Dacron grafts made impervious by a 1.5 mm thick coat of silicone rubber bonded to the external surface were implanted for 4 weeks during the same surgery in the descending thoracic aorta (DTA), abdominal aorta (AA) and inferior vena cava (IVC) of each of five dogs. Flow rates were measured during surgery and shear stresses calculated with the Hagen-Poiseuille formula. Full-wall thickness longitudinal tissue sections were embedded in resin and stained with hematoxylin and eosin for light microscopy, and in paraffin for immunocytochemistry studies with Factor VIII/von Willebrand factor, smooth muscle alpha-actin, collagen IV, laminin, and proliferating cell nuclear antigen. Scanning electron microscopy and transmission electron microscopy studies were also performed. AgNO3 was used to determine percentage of endothelial-like cell coverage on the flow surface. All grafts were patent, without hematoma or seroma. Endothelial-like cell coverage was highest in the IVC grafts and lowest in the DTA. Shear stress and flow velocity were significantly lower in IVC grafts than DTA and AA. Proliferating cell nuclear antigen indicated extensive cellular proliferation in the intima and in the interstices of the inner portion of the graft wall. The degree of fallout healing in knitted Dacron grafts made impervious by an external coat of silicone rubber varies inversely with the sheer force of blood flow in these grafts.

Animals↗
PubMed1998

Effect of skeletonizing dissection on the internal thoracic artery.

BACKGROUND: Skeletonization of the internal thoracic artery (ITA) produces greater length for coronary bypass grafting. We studied the effect of skeletonization on the morphology, histology, and tissue viability of the ITA wall. METHODS: Six mongrel dogs underwent unilateral ITA dissection; the contralateral ITA was the control. Study periods were 3 weeks (n=3) and 12 weeks (n=3). At sacrifice, the entire anterior chest wall was removed and dynamically fixed with formalin. Extensive histologic comparisons were performed on three tissue blocks taken from each ITA, 2, 8, and 24 cm from their origin. RESULTS: Flows at the end of the study were comparable to measurements taken during operation, immediately after skeletonization. Grossly, the ITA wall was not injured by skeletonization and there was no adventitial hematoma or bleeding from the sealed branch ends. Microscopic observations showed intact, normal wall structures. Histologic data showed no major significant difference between controls and skeletonized ITAs. CONCLUSIONS: Careful skeletonizing dissection is not detrimental to the integrity of ITAs, which justifies their use for myocardial revascularization.

Animals↗
PubMed1998

Effects of hyperventilation and hypoventilation on PaCO2 and intracranial pressure during acute elevations of intraabdominal pressure with CO2 pneumoperitoneum: large animal observations.

BACKGROUND: The side effects of acute elevations in intraabdominal pressure (IAP) are related to a multifactorial etiology. Previous studies have reported that acute elevations in IAP produce an immediate increase in intracranial pressure (ICP). This study was designed to analyze the reasons for increased ICP during acute elevations of IAP and to determine the combined effects of IAP and changes in ventilation indices on ICP and hemodynamic indices. STUDY DESIGN: Five pigs were studied. A subarachnoid screw was placed for ICP monitoring. The jugular vein, femoral vein, and femoral artery were cannulated. Mean arterial pressure (MAP), central venous pressure (CVP), ICP, and arterial pressure of carbon dioxide (PaCO2) were monitored before and after carbon dioxide pneumoperitoneum was established at 0, 10, and 20 mmHg of IAP Effects of hyperventilation and hypoventilation were recorded and compared with baseline ventilation. Cavography was performed to evaluate the morphology of the inferior vena cava (IVC) at different levels of IAP. Multiple regression and Student's t-test were used to examine the effects of IAP and ventilation on dependent variables. RESULTS: The IVC showed a progressive narrowing at the level of the diaphragm as IAP was increased. There was a simultaneous increase in CVP, MAP, and ICP. The mean changes in ICP with hypoventilation were significantly larger than with hyperventilation. CONCLUSIONS: Acutely increased IAP displaces the diaphragm cranially, narrowing the IVC and increasing intrathoracic pressure. This increases CVP and increases ICP by venous stasis and increased pressure in the sagittal sinus with decreased resorption of cerebrospinal fluid. Hemodynamic changes are directly related to the rise in ICP. Hypoventilation and hypercarbia significantly increase ICP when compared with hyperventilation and hypocarbia. Hyperventilation does not significantly decrease ICP during acute elevations of IAP.

Abdomen↗
PubMed1998

The effects of serum from patients with acute liver failure on the growth and metabolism of Hep G2 cells.

In many bioartificial liver systems currently being designed and evaluated for use in fulminant hepatic failure, direct contact is required between the patient's blood and the liver cells in the device. The efficacy of such devices will be influenced by the interaction of fulminant hepatic failure (FHF) patient serum with the cells. We have found that FHF serum inhibits the growth rate and the synthesis of DNA, RNA, and protein; disturbs glutathione homeostasis; and induces morphological changes in cultured human Hep G2 cells. These interactions should influence the design of bioartificial liver devices based on proliferating cell lines and indicate the requirement to pretreat FHF patient plasma to reduce the toxin load.

Animals↗
PubMed1998

Tribulusamide A and B, new hepatoprotective lignanamides from the fruits of Tribulus terrestris: indications of cytoprotective activity in murine hepatocyte culture.

Tribulusamides A (1) and B (2), new lignanamides embracing two cinnamic amide parts joined in a cis configuration, were isolated from the fruits of Tribulus terrestris, together with four known compounds, N-trans-feruloyltyramine (3), terrestriamide (4), N-trans-coumaroyltyramine (5), and beta-sitosterol. The structures were elucidated by 2D-NMR spectroscopy. Addition of compounds 1-5, especially 1 and 2, to primary cultured mouse hepatocytes significantly prevented cell death induced by D-galactosamine (D-GalN)/tumor necrosis factor alpha (TNF-alpha).

Animals↗
PubMed1998

Colcemid and econazole do not show aneugenicity in male mouse germ cells.

Colcemid (COM) and econazole (EZ) were tested for induction of mitotic arrest and C-mitotic effects in mouse bone marrow cells and for meiotic delay and induction of hyperploidy in mouse spermatocytes after single injection. Doses of 1 and 3 mg/kg COM were used and bone marrow and spermatocytes were sampled at 2, 6, 10, 14 and 18 h. For EZ a dose of 120 mg/kg and intervals of 6, 10, 14 and 18 h were chosen. At 2 h after COM treatment of bone marrow cells the mitotic index and C-mitotic effect were highest, then both decreased from 6 to 18 h. At 18 h the mitotic indices decreased to or significantly below the control level at doses of 1 and 3 mg/kg respectively, whereas the corresponding frequencies of C-mitotic cells were still significantly higher than in the controls. EZ also induced mitotic arrest and C-mitotic effects in mouse bone marrow cells. In contrast to COM, the effects of EZ were highest at 18 h after treatment. COM and EZ caused disturbances in progression from the first to second meiotic division, however, after COM treatment the ratios of MMII to MMI were significantly below the control. In contrast, after EZ treatment the ratios were significantly higher than in the controls. Such differences may result from the different mechanisms by which COM and EZ act on cell cycle progression. COM and EZ did not induce non-disjunction under the experimental conditions. However, EZ induced structural chromosomal aberrations.

Animals↗
PubMed1998

Castration differentially regulates nitric oxide synthase in the hypothalamus and pituitary.

Mammalian reproductive function is under control of the integrated hypothalamic-pituitary-gonadal (HPG) axis. Castration in male rats has been utilized as an effective tool to investigate hormonal interactions in the mammalian HPG axis. Recently, nitric oxide (NO) has been suggested to play a role in HPG hormonal regulation. In order to gain further insight into the function of the NO-NOS system in reproductive neuroendocrine control, particularly in the gonadal feedback regulation of the hypothalamic-pituitary unit, we examined steady state levels of nNOS mRNA, nNOS protein, and the important physiological index, NOS enzyme activity, of the intrinsic NOergic system in both hypothalamus and pituitary in castrated male rats and their sham-operated counterparts one week after surgery. In the pituitary, we found a significant four-fold increase in nNOS mRNA, p < 0.0003 compared to sham. Castration also resulted in a four-fold rise in pituitary nNOS protein, p < 0.02 compared to sham. Pituitary NOS enzyme activity was stimulated 2 fold, p < 0.003 after castration. In the hypothalamus, conversely, we observed no significant castration-modulated difference in either nNOS mRNA, nNOS protein or NOS enzyme activity. Thus, it appears that the hypothalamic NO-NOS system is either not required for hypothalamic adaptations to castration, although important in the release of LHRH under normal physiological conditions, or alternatively, the hypothalamus may become more sensitive to the effects of NO in the castrated state. In the pituitary, NO may attenuate the gonadotropin response to castration as a local balancing mediator.

Animals↗
PubMed1998

Recent progress in the development of tubulin inhibitors as antimitotic antitumor agents.

Tubulin protein is a major target of drug molecules, and consequently, tubulin inhibitors have attracted great attention as antimitotic antitumor agents for chemotherapeutic use. Hundreds of synthetic or semisynthetic tubulin inhibitors have been discovered and developed recently that are related to the natural products colchicine, vinblastine, and taxol. Representatives include allothiocolchicinoids, vinorelbine, and taxotere. This review will describe the recent progress being made in the development of novel antimitotic antitumor tubulin inhibitors. The emphasis has been placed on related research in the author's laboratory, including development of colchicine derivatives and other colchicine binding site drugs, such as flavonoids and quinolone derivatives. Syntheses and modifications of novel compounds, biological activity evaluation, and structural activity relationships will be discussed as well. Further research will undoubtedly lead to the discovery of additional tubulin inhibitors that have potential for use as anticancer drugs.

Antineoplastic Agents↗
PubMed1998

[Discovery of ten strains of non-O1 Vibrio cholerae pigmentogens].

OBJECTIVE: To study the distribution of non-O1 Vibrio cholerae pigmentogens in water and its biological characteristics and pathogenicity. METHODS: Samples were collected from local source of drinking water and cultured for pathogenic V. cholerae. Non-O1 V. cholerae was isolated and identified with nutrient agar slant instead of KIA. RESULTS: Ten strains of V. cholerae producing pigment with negative Gram's stain were detected in the source water in Lu' an Prefecture, Anhui Province during 1994 to 1997, which could all met the definition of non-O1 V. cholerae in morphology, cultural characteristics, biochemistry and serology, with systematic identification. Animal experiments showed that it had strong virulence. CONCLUSION: These strains of V. cholerae cultured in basic cholate agar, nutrient agar slant and blood agar could produce brown pigment, so it was called non-O1 V. cholerae pigmentogens.

Animals↗
PubMed1998

[The genomic characterization of the Cuban strain with a light cytopathic effect].

The genomic characterization of the strain of light cytopathic effect by nucleotide sequence is presented. It was possible to sequence 90% of the strain of light cytopathic effect. A close relationship with Coxsackie A9 was observed. The greatest mutations occurred in the region of the genome that codifies for the structural proteins. Therefore, it may be considered as a variant of Coxsackie A9 never reported before.

Animals↗
PubMed1998

[The changes of serum estrogen, progesterone and the function of immune system in intrahepatic cholestasis of pregnancy].

OBJECTIVE: To explore the effects of estrogen, progesterone and the function of immune system on intrahepatic cholestasis of pregnancy (ICP). METHODS: Fifty women with ICP and fifty normal pregnant women were enrolled in the study. The levels of their serum estradiol (E2) and progesterone (P) were measured and cellular immunity and humoral immunity were determined. Radioimmunoassay was used to detect the levels of E2 and P, and APAAP was used to detect cellular immunity. RESULTS: (1) The level of estrodiol was significantly increased in ICP group than those of normal control group (25.89 +/- 6.85 micrograms/L, 16.92 +/- 4.98 micrograms/L, P < 0.01). (2) The level of CD8+ was decreased (19.06 +/- 1.93%, 26.43 +/- 2.89%) and the ratio of CD4+/CD8+ was increased significantly in ICP group than those of control group (2.23 +/- 0.38, 1.73 +/- 0.23, P < 0.05). (3) There were negative correlation between E2 and CD8+, and positive correlation between E2 and the ratio of CD4+/CD8+. CONCLUSION: These results suggest that the high level of E2 of ICP patients may result in functional disorder of immune system by the means of estrogen receptor on CD8+. This may be a factor of ICP development.

Adult↗
PubMed1998

[A modified laryngectomy combined with radical neck dissection for late-staged supraglottic carcinoma].

8 cases of supraglottic or transglottic carcinoma with neck lymphatic metastasis received a modified laryngectomy or subtotal laryngectomy combined with radical neck dissection. Laryngeal function was reconstructed in 3 of them. No postoperative complication occurred. All cases survived uneventfully through a five-year following up, except one who died of neck lymphatic and lung metastasis. The indication, procedure and advantage of this operation are discussed in this article.

Aged↗