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Biomedical subjects

X Sun

Publications and source records attributed to X Sun.

At least 451 records · Page 25Linked to original sources
PubMed1995

Ovarian mesothelial and extramesothelial cells in interactive culture.

The ovarian mesothelium (OM) represents the tissue of origin of ovarian epithelial cancer. To gain insight into the regulation of this tissue, OM organoids and submesothelial ovarian stromal cells (SC) were isolated from New Zealand White rabbits by a stepwise tissue dispersal technique, while granulosa cells (GC) were aspirated from mature follicles (14 +/- 4 groups/animal). OM and SC dispersal were sequentially accomplished by: a) 1-h incubation in collagenase type I (300 U/ml), gentle scraping of the ovarian surface, and 1 g sedimentation of OM organoids (equivalent to 0.93 +/- 0.40 x 10(6) cells/animal) on 5% bovine serum albumin (BSA); b) 2-h incubation in pronase-collagenase (0.5%-300 U/ml) under periodical resuspension and gentle scraping of SC (1.40 +/- 0.25 x 10(6)/animal) from OM-denuded ovaries. After a week-long in vitro expansion, OM cells (OMC) were cultured alone and with SC or GC within monocameral vessels or bicameral transfilter vessels in serumless, fibronectinrich (4 micrograms/ml) HL-1 medium. After 7 d of contact cell-cell interaction, cytokeratin-positive OMC became surrounded by fibroblastoid, vimentin-positive SC or by cytokeratin and vimentin-weakly positive GC. Filter-bound OMC humorally interacting with underlying SC or GC displayed a biphasic, epithelioid and spindle, morphology with universal cytokeratin expression. Bromo-2'-deoxyuridine (BrdU) immunoperoxidase revealed mean cell proliferation indices of 14.88% for OMC cultured alone, 11.21% and 19.39% for OMC cultured with GC or SC in monocameral dishes, and 15.25% or 22.47% for OMC cultured in bicameral vessels over GC or SC, respectively. This model provides an experimental tool for investigating the unexplored role of stromal-mesothelial interaction in OM pathobiology.

Animals↗
PubMed1995

Luxury perfusion phenomenon in acute herpes simplex virus encephalitis.

In a patient with acute herpes simplex virus (HSV) encephalitis, positron emission tomography (PET) demonstrated increased cerebral blood flow in the affected temporal lobe accompanied by reduction in the cerebral oxygen extraction fraction and the cerebral metabolic rate of oxygen, i.e., luxury perfusion. Follow-up PET studies showed reduction in cerebral perfusion until it was more closely coupled with oxygen metabolism after the resolution of the acute inflammation. These findings support previous single photon emission computed tomographic data and provide a pathophysiological background for the occurrence of hyperperfusion in HSV encephalitis. This is an interesting example of the luxury perfusion phenomenon occurring in a disease other than cerebral ischemia.

Adult↗
PubMed1995

Non-iron mediated alteration in hepatic transferrin gene expression in the nephrotic rat.

Both transferrin and the iron it carries are lost in the urine in the nephrotic syndrome. Patients may develop hypochromic microcytic anemia and synthesis of transferrin, a protein regulated in large part by iron availability, is increased. Transferrin synthesis has also been reported to be increased in liver slices from rats with hereditary analbuminemia, and their plasma transferrin levels are increased, suggesting that transferrin synthesis may be stimulated by processes other than iron depletion in this hypoalbuminemic condition. Transferrin metabolism was studied in rats with Heymann nephritis (HN), in a strain of Sprague-Dawley (SD) rats with hereditary analbuminemia [Nagase analbuminemic rats (NAR)], and in normal SD rats. Plasma transferrin concentration and mass was decreased significantly in HN, but increased in NAR. Transferrin synthesis was increased both in NAR (measured either as the disappearance of [125I] labeled transferrin or as the incorporation of [3H] phenylalanine) and in HN (incorporation of [3H] phenylalanine). The fractional rate of transferrin catabolism was unchanged in NAR. Thus transferrin mass was increased in NAR entirely as a consequence of increased synthesis. Transferrin and albumin synthesis correlated with one another in both HN and SD (P < 0.001). Transferrin mRNA was increased in both HN and NAR and was unaffected by administration of iron to HN. Hepatic transferrin and albumin mRNA levels were also correlated positively in HN and SD, suggesting that increased hepatic synthesis of both proteins might be responding to the same stimuli. Transferrin gene transcription was increased in both HN and NAR and was unaffected by administration of iron to HN. Transferrin mRNA was not increased in the testis in either HN or NAR, suggesting that augmentation in transferrin gene expression is driven by a non-iron dependent process and is confined to the liver.

Albumins↗
PubMed1995

Identification of a novel p53 promoter element involved in genotoxic stress-inducible p53 gene expression.

p53 is recruited in response to DNA-damaging genotoxic stress and plays an important role in maintaining the integrity of the genome. We show that exposure of cells to various genotoxic agents, including anticancer drugs such as mitomycin and 5-fluorouracil, results in an increase in p53 mRNA levels and in p53 promoter activation, indicating that the p53 genotoxic stress response is partly regulated at the transcriptional level. The results of the p53 promoter analysis show that a novel p53 promoter element, termed a p53 core promoter element (from -70 to -46), is essential for basal p53 promoter activity and promoter activation induced by genotoxic agents such as anticancer drugs and UV. Although a kappa B motif partially overlaps with this element and those genotoxic agents activate NF-kappa B, it does not play a major role in p53 genotoxic stress response: NF-kappa B p65 expression did not induce significant p53 promoter activation, and NF-kappa B inhibitors (N-acetyl cysteine and I kappa B alpha) did not inhibit genotoxic stress-inducible p53 promoter activation. Finally, we characterized nuclear factors, the binding of which to the p53 core promoter element is essential for basal p53 promoter activity and p53 promoter activation induced by genotoxic agents.

Animals↗
PubMed1995

Low temperature growth, freezing survival, and production of antifreeze protein by the plant growth promoting rhizobacterium Pseudomonas putida GR12-2.

The plant growth promoting rhizobacterium Pseudomonas putida GR12-2 was originally isolated from the rhizosphere of plants growing in the Canadian High Arctic. Here we report that this bacterium was able to grow and promote root elongation of both spring and winter canola at 5 degrees C, a temperature at which only a relatively small number of bacteria are able to proliferate and function. In addition, the bacterium survived exposure to freezing temperatures, i.e., -20 and -50 degrees C. In an effort to determine the mechanistic basis for this behaviour, it was discovered that following growth at 5 degrees C, P. putida GR12-2 synthesized and secreted to the growth medium a protein with antifreeze activity. Analysis of the spent growth medium, following concentration by ultrafiltration, by SDS-polyacrylamide gel electrophoresis revealed the presence of one major protein with a molecular mass of approximately 32-34 kDa and a number of minor proteins. However, at this point it is not known which of these proteins contains the antifreeze activity.

Antifreeze Proteins↗
PubMed1995

Evolution of beta-cell dysfunction in the male Zucker diabetic fatty rat.

The molecular basis for the beta-cell dysfunction that characterizes non-insulin-dependent diabetes mellitus (NIDDM) is unknown. The Zucker diabetic fatty (ZDF) male rat is a rodent model of NIDDM with a predictable progression from the prediabetic to the diabetic state. We are using this model to study beta-cell function during the development of diabetes with the goal of identifying genes that play a key role in regulating insulin secretion and, thus, may be potential targets for therapeutic intervention aimed at preserving or improving beta-cell function. As a first step, we have characterized morphology, insulin secretion, and pattern of gene expression in islets from prediabetic and diabetic ZDF rats. The development of diabetes was associated with changes in islet morphology, and the islets of diabetic animals were markedly hypertrophic with multiple irregular projections into the surrounding exocrine pancreas. In addition, there were multiple defects in the normal pattern of insulin secretion. The islets of prediabetic ZDF rats secreted significantly more insulin at each glucose concentration tested and showed a leftward shift in the dose-response curve relating glucose concentration and insulin secretion. Islets of prediabetic animals also demonstrated defects in the normal oscillatory pattern of insulin secretion, indicating the presence of impairment of the normal feedback control between glucose and insulin secretion. The islets from diabetic animals showed further impairment in the ability to respond to a glucose stimulus. Changes in gene expression were also evident in islets from prediabetic and diabetic ZDF rats compared with age-matched control animals. In prediabetic animals, there was no change in insulin mRNA levels. However, there was a significant 30-70% reduction in the levels of a large number of other islet mRNAs including glucokinase, mitochondrial glycerol-3-phosphate dehydrogenase, voltage-dependent Ca2+ and K+ channels, Ca(2+)-ATPase, and transcription factor Islet-1 mRNAs. In addition, there was a 40-50% increase in the levels of glucose-6-phosphatase and 12-lipoxygenase mRNAs. There were further changes in gene expression in the islets from diabetic ZDF rats, including a decrease in insulin mRNA levels that was associated with reduced islet insulin levels. Our results indicate that multiple defects in beta-cell function can be detected in islets of prediabetic animals well before the development of hyperglycemia and suggest that changes in the normal pattern of gene expression contribute to the development of beta-cell dysfunction.

Animals↗
PubMed1995

[Tumor recurrence prevention using photodynamic therapy after treatment of bladder cancer].

Photodynamic therapy with hematoporphyrin derivative was given to 21 patients with recurrent transitional cell carcinoma of the bladder. Each patient received red light (630nm) derived from a gold-vapor laser machine into the bladder. The light dose was given to the whole bladder by using the bulb diffuser with power density ranging from 36 to 72J/cm2. All patients had a complete response at 6 months. Three of the 21 patients had tumor recurrence at 12 months. This new light delivery system appears to be effective in the prevention of bladder cancer. Photochemotherapy is as useful as bladder chemotherapy. Its preventive effect will be elevated if it is repeated 6-12 months after first treatment.

Aged↗
PubMed1995

[Clinical observation of posterior chamber lens implantation in children].

Extracapsular cataract extraction with posterior chamber intraocular lens (IOL) implantation was performed on 22 eyes of 16 patients with congenital or traumatic cataract and with ages ranging from 4 to 7 years old. The periods of follow-up were 1-2 years with a mean, 18 months. The postoperative reaction was mild, no untoward complications occurred in the remote follow-up and the postoperative visual acuities recovered well. The youngest age of IOL implantation, the choice of diopter of refraction and the management of intra- and post-operative complications were discussed.

Age Factors↗
PubMed1995

[Quality standards of effervescent granules for the treatment of cold pain].

Thin layer chromatography was performed to identify the ingredients of Effervescent Granules for arresting cold pain (Hantongding Paoteng Chongji). The limited doses of aconitine, granularity, moisture, acidity, sugar content, etc. were detected, and the contents of paeoniflorin, glycyrrhetinic acid and total alkaloids were determined. Thus, the quality standards for pharmaceutical preparation were preliminarily worked out.

Aconitine↗
PubMed1995

[Management of intestinal obstruction in advanced ovarian cancer an analysis of 57 cases].

The records of 532 patients with advanced ovarian cancer during March 1977 to February 1993 were retrospectively reviewed. Fifty-seven cases developed intestinal obstruction, and 54 cases died of this complication. The median survival period for all patients with obstruction was 110 days, and only 5 cases survived for more than one year. Twenty-three cases were treated mainly by surgery, 18 by chemotherapy, and 16 by conservative measures. The median survival periods for each group was 96 days, 120 days, and 81 days, respectively. Their survival times are not statistically different (P > 0.05). Of the patients surgically treated, 61% (14/23) benefited from operation, 26% (6/23) had inoperable disease at laparotomy, and 9% (2/23) developed fatal surgical complications. Even though the response rate in patients receiving chemotherapy was much higher than in those surgically treated (P < 0.05), the effect of chemotherapy was just temporary, and occurred only in patients who had never been treated with high dose PDD-based regimens. In this report, the individualized management of intestinal obstruction induced by ovarian cancers is suggested, and indications and contraindications for three treatment modalities are proposed.

Adolescent↗
PubMed1995

Significance of flow cytometry in the diagnosis and treatment of bladder tumors.

The results of application of flow cytometry (FCM) in analysis of 139 bladder irrigations of DNA contents in tumor cells from 52 cases of bladder tumors are reported. A comparison was made between this assay and cytological examinations as well as pathological grading. The results suggested that the accuracy of cytological analysis was apparently lower than the cell DNA measurement by flow cytometry, the higher the tumor pathological grading and the deeper the infiltration, the higher the heteroploid DNA contents in the tumor cells. Treatment of high heteroploid bladder tumor required radical cystectomy while the efficiency of simple electrosection or partial cystectomy appeared inferior. When FCM and the bladder tumor pathological grading had a high degree of correlation, especially in the high grading tumor, recurrence was high even when chemical treatment with bladder instillation of BCG was adopted. However, FCM cannot substitute for cystoscopy.

Adult↗
PubMed1995

[An analysis of causes of post-operative shallow anterior chamber in glaucoma filtering surgery].

131 eyes of 103 cases having undertaken glaucoma filtering surgeries were randomly selected to analyze retrospectively the causes of the post-operative shallow anterior chamber. The causes are choroidal detachment accounting for 75.6%, excessive filtration 13.3% and malignant glaucoma 11.1%. As the rate of discovery of the choroidal detachment under a direct ophthalmoscope was quite low, the definite diagnosis depended primarily on B-ultrasonography. It is discovered that in the analysis of the possible factors leading to choroidal detachment, the plasma level of fibronectin is correlated to the development of the post-operative choroidal detachment of a glaucoma filtering operation, suggesting the impairment of microcirculatory function be investigated to approach the causes of the choroidal detachment following anti-glaucoma and other intraocular surgeries.

Adult↗
PubMed1995

[The effect of prostaglandin E1 on myocardial ischemia reperfusion injury].

The effect of prostaglandin E1 (PGE1) on ischemia reperfusion injury (IRI) was investigated. The changes of leucocytes in venous blood and infarcted myocardial tissue and the level of lipid peroxide (LPO), superroxide dismutase (SOD) and catalase (CAT) were also studied in these animal models at the same time. The experimental results were as follows: the count and activity of leucocytes and the level of LPO in IRI were obviously increased. The activity of SOD and CAT in the untreated group was much lower than that in the treated group (P < 0.01). The infarcted size (IS) was larger in the untreated group. The count of leucocytes was positively related with the level of LPO and IS, but negatively related with the activity of SOD and CAT. However, the relationship disappeared after the administration of PGE1. These data suggested that leucocyte plays an important role in IRI. PGE1 can inhibit leucocyte activity, decrease peroxidation, reduce LPO production and increase the activity of SOD and CAT. It can decrease the infarct size. PGE1 takes the main role in protecting IRI.

Alprostadil↗
PubMed1995

[Influence of Cinnamomum migao H.W.Li oil on hemodynamic action in anesthetized cats].

Cinnamomum migao oil (CV-3) 0.2ml.kg-1 was intraduodenum given to anesthetized open-chest cats. Ninety minutes after treatment with the oil, the SAP and DAP were slowly reduced to 15.2% and 14.2%, respectively. At the sametime, the HR was slowed down and CO decreased. The left ventricular pressure (LVP), the left ventricular end diastolic pressure (LVEDP), dp/dtmax and Vmax were remarkably reduced respectively. The LVP-(dp/dtmax)P-1 loop was narrowed. Isosorbide dinitrate showed similar effects to CV-3.

Animals↗