Biomedical subjects

X Ye

Publications and source records attributed to X Ye.

At least 109 records · Page 6Linked to original sources

PubMed1999

3-Nitropropionic acid (3-NPA) produces hypothermia and inhibits histochemical labeling of succinate dehydrogenase (SDH) in rat brain.

3-Nitropropionic acid (3-NPA) is a toxin sometimes produced on moldy crops (sugarcane, peanuts, etc.) in amounts sufficient to cause severe neurological disorders when consumed by humans. In vitro, 3-NPA irreversibly inactivates SDH, a Complex II respiratory enzyme required for mitochondrial energy production. A single dose of 3-NPA (30 mg/kg s.c.) was given to singly-caged adult male Sprague-Dawley rats. Rectal temperature was measured after dosing as a potential biomarker of exposure to 3-NPA, and animals were sacrificed at various times after 3-NPA exposure for histochemical visualization of SDH activity. 3-NPA-treated rats experienced a progressive hypothermia, which reached a loss of 3 degrees C or more in core body temperature by 3 hours after dosing. The optical density of the SDH stain in brain was reduced according to a similar time-course, most prominently in the cerebellum and least sharply in the thalamus. The caudate nucleus had the greatest density of SDH staining that we measured in brain; it also has been reported to be the region most consistently lesioned by 3-NPA. However, within other areas of brain such as subdivisions of the hippocampus, neither endogenous SDH activity nor its sensitivity to inhibition by 3-NPA could predict the susceptibility to neurodegenerative changes. Although SDH activity remained significantly reduced in most areas of brain (except thalamus) for up to 5 days after dosing, core temperatures had returned to control values by 5 days suggesting that animals can utilize an alternate method of heat production to withstand insult by 3-NPA.

Animals↗

PubMed1999

Mechanism of gastroprotection by bismuth subsalicylate against chemically induced oxidative stress in cultured human gastric mucosal cells.

Reactive oxygen species (ROS) are implicated in the pathogenesis of chemically induced gastric mucosal injury. We have investigated the effects of ethanol, hydrochloric acid (HCl), and sodium hydroxide (NaOH) on: (1) enhanced production of ROS including superoxide anion and hydroxyl radicals, (2) modulation of intracellular oxidized states by laser scanning confocal microscopy, and (3) DNA fragmentation, indices of oxidative tissue, and DNA damage in a primary culture of normal human gastric mucosal cells (GC), which were isolated and cultured from Helicobacter pylori-negative endoscopic biopsies from human subjects. The induction of ROS and DNA damage in these cells following exposure to ethanol (15%), HCl (150 mM) and NaOH (150 mM) were assessed by cytochrome c reduction (superoxide anion production), HPLC detection for enhanced production of hydroxyl radicals, changes in intracellular oxidized states by laser scanning confocal microscopy, and DNA damage by quantitating DNA fragmentation. Furthermore, the protective ability of bismuth subsalicylate (BSS) was assessed at concentrations of 25, 50, and 100 mg/liter. Incubation of GC with ethanol, HCI, and NaOH increased superoxide anion production by approximately 8.0-, 6.1-and 7.1-fold and increased hydroxyl radical production by 13.3-, 9.6-, and 8.9-fold, respectively, compared to the untreated gastric cells. Incubation of GC with ethanol, HCl, and NaOH increased DNA fragmentation by approximately 6.7-, 4.3-, and 4.8-fold, respectively. Approximately 20.3-, 17.5-, and 13.1-fold increases in fluorescence intensities were observed following incubation of gastric cells with ethanol, HCl, and NaOH, respectively, demonstrating dramatic changes in the intracellular oxidized states of GC following exposure to these necrotizing agents. Preincubation of GC with 25, 50, and 100 mg/liter of BSS decreased ethanol-induced increases in intracellular oxidized states in these cells by 36%, 56%, and 66%, respectively, demonstrating a concentration-dependent protective ability by BSS. Similar results were observed with respect to BSS in terms of superoxide anion and hydroxyl radical production, and DNA damage. The present study demonstrates that ethanol, HCl, and NaOH induce oxidative stress and DNA damage in GC and that BSS can significantly attenuate gastric injury by scavenging these ROS.

Bismuth↗

PubMed1999

Neurotrophin dependence mediated by p75NTR: contrast between rescue by BDNF and NGF.

During development, neurons pass through a critical phase in which survival is dependent on neurotrophin support. In order to dissect the potential role of p75NTR, the common neurotrophin receptor, in neurotrophin dependence, we expressed wild-type and mutant p75NTR in cells that do not express endogenous p75NTR or Trk family members (NIH3T3). Expression of wild-type p75NTR created a state of neurotrophin dependence: cells could be rescued by nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), or neurotrophin-3 (NT-3), but not by a mutant NGF that binds well to Trk A but poorly to p75NTR. Similarly, expression of p75NTR in human prostate cancer cells in culture rendered a metastatic tumor cell line (PC-3) sensitive to the availability of neurotrophins for survival. Moreover, expression of mutant p75NTR's in another neurotrophin-insensitive cell line (HEK293T) showed that a domain within the intracellular domain governs alternate responses to neurotrophins: the carboxy terminus of the intracellular domain of p75NTR including the sixth alpha helix domain is necessary for rescue by BDNF, but not NGF. These results, when considered with previous studies of the timing of p75NTR expression, support the hypothesis that p75NTR is a mediator of neurotrophin dependence during the critical phase of developmental cell death and during the progression of carcinogenesis in prostate cancer.

3T3 Cells↗

PubMed1999

Analysis of genetic polymorphisms in the major histocompatibility complex of Japanese quail.

The restriction fragment length polymorphisms (RFLP) of the Japanese quail MHC were assayed in seven lines using PvuII-digested DNA and a chicken Class II probe. The lines of Japanese quail surveyed included a randombred control population (R1) and sublines of R1 divergently selected for 4-wk body weight (HW and LW lines) or plasma yolk precursor as measured by total plasma phosphorus (TPP) (HP and LP lines). In addition, two sublines (HW-HP and HW-LP) of the HW line were included in the analysis. Males of both sublines were selected for increased 4-wk body weight whereas the females were selected for increased (HW-HP) or decreased (HW-LP) TPP. The number of birds surveyed per line ranged from 13 to 16. The chicken probe used produced discernible bands or fragments using Southern blot analysis. There were 16 different RFLP patterns as well as 7 different heterozygote patterns detected in the various Japanese quail lines. The band or fragment number of each pattern varied from 7 to 15. A total of 28 different bands or fragments were seen in the RFLP patterns and only 2 bands or fragments were common to all 16 patterns. The distribution of the RFLP patterns differed greatly among the Japanese quail lines. The R1 line differed in frequency of the patterns from all of the selected lines. The divergently selected lines (HW vs LW; HP vs LP; and HW-HP vs HW-LP) also differed in the frequency of the various RFLP patterns. In the comparison of the HW and LW lines, there were no RFLP patterns in common between the two lines. The results of the present study indicated that the Japanese quail MHC Class II genes were highly polymorphic.

Animals↗

PubMed1999

Genetic relationship among lines and smooth muscle and ovarian follicular development within lines of Japanese quail in two long-term selection studies.

Smooth muscle tumor and ovarian follicular development were studied in lines of Japanese quail selected for increased 4-wk BW (HW, P, and T) and their randombred controls (C and R1). The lines studied were from long-term selection studies at The Ohio State University (HW and R1) and The University of Georgia (P, T, and C). To study the genetic relationship among the lines in the two selection studies, the C, P, HW, and R1 lines were DNA-fingerprinted by digestion of the DNA with the HaeIII restriction enzyme and using Jeffreys' 33.6 probe. The BW of females at 4 wk of age and at the end of a 240-d egg production period were similar for the C and R1 lines. The BW of the selected lines was ranked P > T > HW for both measurements. Smooth muscle tumors were found in the oviducal ligaments adjacent to the magnum. A greater percentage of hens from the BW-selected lines had smooth muscle tumors of greater weight than the randombred control lines, which did not differ in tumor incidence or weight. The P and T lines had a greater incidence of multiple-lobed tumors than the HW line. Based on bandsharing (BS) of DNA fingerprints, the Georgia and Ohio lines did not appear to be closely related, suggesting that, perhaps, the smooth muscle tumors in the BW-selected lines in the two studies might have resulted from pleiotrophic effects of genes affecting growth or to genes closely linked to the growth genes. The BW-selected lines in both selection studies had more ovarian follicles in rapid development, which were of greater weight, than the randombred control lines. The HW line had a larger number of ovarian follicles in rapid development than the P and T lines. The percentage of hens with atretic follicles was greater in the BW-selected lines. The results of the present study suggest that the effect of BW selection on ovarian follicular development may occur early in selection (within the first 30 generations) and is not influenced by additional genetic changes in BW.

Animal Husbandry↗

PubMed1999

QT dispersion in children with ventricular arrhythmia and a structurally normal heart.

In adults, increased QT dispersion has been shown to predict arrhythmic risk as well as risk of sudden death in several clinical settings. It is not known whether or not QT dispersion is increased in children with idiopathic ventricular arrhythmia. We studied three groups of children: (1) 20 patients with idiopathic VT (aged 3-18 years; mean 11.2 years); (2) 30 patients with benign PVCs (aged 1-20 years; mean 10.5 years); and (3) 30 control subjects (aged 4-17 years; mean 12 years). Standard ECGs were reviewed and the dispersion of both QT and JT intervals was compared. No patient had structural heart disease or long QT syndrome. The QT and QTc dispersion (QT delta, QTc delta) among the three groups did not differ: QTc delta of the VT group was 70 ms +/- 30 ms, QTc delta of PVC patients was 60 ms +/- 30 ms, and the QTc delta of the control group was 65 ms +/- 30 ms. The JTc delta among the three groups did not differ as well: JTc delta of the VT group was 70 ms +/- 30 ms, the JTc delta of the PVC group was 60 msec +/- 25 msec, and the JTc delta of the control group was 70 ms +/- 30 ms. We conclude that QT and JT dispersion are not significantly altered in children with idiopathic VT or benign PVCs when compared to control subjects. QT dispersion is not a reliable marker for arrhythmic risk in children with idiopathic ventricular arrhythmias and structurally normal hearts.

Case-Control Studies↗

PubMed1999

Correction of ureagenesis after gene transfer in an animal model and after liver transplantation in humans with ornithine transcarbamylase deficiency.

We report effects of gene transfer and liver transplantation on urea synthesis in ornithine transcarbamylase deficiency (OTCD). We measured the formation of [15N] urea after oral administration of 15NH4Cl in two girls with partial OTCD before and after liver transplantation. Ureagenesis was less than 20% of that observed in controls before transplantation, and was normalized afterward. Studies performed on the OTCD sparse fur (spf/Y) mouse showed discordance between OTC enzyme activity and ureagenesis with modest increases in OTC enzyme activity after gene transfer resulting in significant improvement in ureagenesis. This study suggests that both liver transplantation and gene therapy may be effective in improving ureagenesis in OTCD.

Animals↗

PubMed1999

Abnormal periodic acid-Schiff (PAS)-positive substance in the islets of Langerhans, pituitaries and adrenal glands of 139H scrapie-infected hamsters.

Previous studies showed that the 139H strain of scrapie injected intra-cerebrally in hamsters caused obesity, and extensive histopathological changes in islets of Langerhans and pituitaries. In the current study, we report that an abnormal granular substance, which stained positively with periodic acid-Schiff (PAS-positive substance; PPS), was found in the islets of Langerhans, pituitaries, adrenal glands, in the lumens of blood vessel cores (BVCs) and in blood vessels in 139H-infected hamsters, but not in either 263K-infected or control hamsters. This substance was found in the endocrine organs, forming grape-like or plaque-like structures, which were small, round to ovoid, and homogenous measuring up to 7 microns in diameter and usually grouped in clusters. PPS was not found in the brains of control or scrapie-infected hamsters. Using immunostaining for amyloid protein (PrP, beta A4), as well as Congo red and thioflavin-S stains, no evidence was found of amyloid plaque formation in the islets of Langerhans, the adrenal glands, or the pituitaries of 139H- or 263K-infected hamsters. PPS might relate to the pathological changes in the endocrine organs in 139H-infected hamsters.

Adrenal Glands↗

PubMed1999

Pyrrolidine dithiocarbamate prevents I-kappaB degradation and reduces microvascular injury induced by lipopolysaccharide in multiple organs.

Lipopolysaccharide (LPS) is a key mediator of multiple organ injury observed in septic shock. The mechanisms responsible for LPS-induced multiple organ injury remain obscure. In the present study, we tested the hypothesis that the LPS-induced injury occurs through activation of the transcription factor, nuclear factor-kappaB (NF-kappaB). We examined the effects of inhibiting NF-kappaB activation in vivo in the rat on LPS-induced: 1) gene and protein expression of the cytokine-inducible neutrophil chemoattractant (CINC) and intercellular adhesion molecule-1 (ICAM-1); b) neutrophil influx into lungs, heart, and liver; and c) increase in microvascular permeability induced by LPS in these organs. LPS (8 mg/kg, i.v.) challenge of rats activated NF-kappaB and induced CINC and ICAM-1 mRNA and protein expression. Pretreatment of rats with pyrrolidine dithiocarbamate (50, 100, and 200 mg/kg, i.p.), an inhibitor of NF-kappaB activation, prevented LPS-induced I-kappaBalpha degradation and the resultant NF-kappaB activation and inhibited, in a dose-related manner, the LPS-induced CINC and ICAM-1 mRNA and protein expression. Pyrrolidine dithiocarbamate also markedly reduced the LPS-induced tissue myeloperoxidase activity (an indicator of tissue neutrophil retention) and the LPS-induced increase in microvascular permeability in these organs. These results demonstrate that NF-kappaB activation is an important in vivo mechanism mediating LPS-induced CINC and ICAM-1 expression, as well as neutrophil recruitment, and the subsequent organ injury. Thus, inhibition of NF-kappaB activation may be an important strategy for the treatment of sepsis-induced multiple organ injury.

Animals↗

PubMed1999

Efficient mitochondrial import of newly synthesized ornithine transcarbamylase (OTC) and correction of secondary metabolic alterations in spf(ash) mice following gene therapy of OTC deficiency.

BACKGROUND: The mouse strain sparse fur with abnormal skin and hair (spf(ash)) is a model for the human ornithine transcarbamylase (OTC) deficiency, an X-linked inherited urea cycle disorder. The spf(ash) mouse carries a single base-pair mutation in the OTC gene that leads to the production of OTC enzyme at 10% of the normal level. MATERIALS AND METHODS: Recombinant adenoviruses carrying either mouse (Ad.mOTC) or human (Ad.hOTC) OTC cDNA were injected intravenously into the spf(ash) mice. Expression of OTC enzyme precursor and its translocation to mitochondria in the vector-transduced hepatocytes were analyzed on an ultrastructural level. Liver OTC activity and mitochondrial OTC concentration were significantly increased (300% of normal) in mice treated with Ad.mOTC and were moderately increased in mice receiving Ad.hOTC (34% of normal). The concentration and subcellular location of OTC and associated enzymes were studied by electron microscope immunolocalization and quantitative morphometry. RESULTS: Cytosolic OTC concentration remained unchanged in Ad.mOTC-injected mice but was significantly increased in mice receiving Ad.hOTC, suggesting a block of mitochondria translocation for the human OTC precursor. Mitochondrial ATPase subunit c [ATPase(c)] was significantly reduced and mitochondrial carbamy delta phosphate synthetase I (CPSI) was significantly elevated in spf(ash) mice relative to C3H. In Ad.mOTC-treated mice, the hepatic mitochondrial concentration of ATPase(c) was completely normalized and the CPSI concentration was partially corrected. CONCLUSIONS: Taken together, we conclude that newly synthesized mouse OTC enzyme was efficiently imported into mitochondria following vector-mediated gene delivery in spf(ash) mice, correcting secondary metabolic alterations.

Adenoviridae↗

PubMed1999

The cytotoxic effects of a novel IH636 grape seed proanthocyanidin extract on cultured human cancer cells.

Grape seed proanthocyanidins are natural antioxidants which possess a broad spectrum of chemoprotective properties against free radicals and oxidative stress. In this study, we have assessed the cytotoxicity of a novel IH636 grape seed proanthocyanidin extract (GSPE) against MCF-7 human breast cancer cells, A-427 human lung cancer cells, CRL-1739 human gastric adenocarcinoma cells and K562 chronic myelogenous leukemic cells at 25 and 50 mg/lit concentrations for 0-72 h using cytomorphology and MTT cytotoxicity assay. In addition, we compared the effects on normal human gastric mucosal cells and normal J774A.1 murine macrophage cells with the effects on the cancer cell lines. Concentration- and time-dependent cytotoxic effects of GSPE were observed on the MCF-7 breast cancer, A-427 lung cancer and gastric adenocarcinoma cells. Following incubation of the MCF-7 cells with 25 mg/lit of the GSPE approximately 6.5, 30 and 43% inhibitions in cell growth were observed at 24, 48 and 72 h of incubation, respectively, while incubation of the MCF-7 cells with 50 mg/lit of the GSPE resulted in 11, 35 and 47% inhibition in cell growth at these same points, respectively. Similar results were observed in the A-427 and gastric adenocarcinoma cells. GSPE exhibited no cytotoxicity toward the neoplastic K562 myelogenous leukemic cells. However, GSPE enhanced the growth and viability of the normal human gastric mucosal cells and J774A.1 murine macrophage cells. These data demonstrate that GSPE exhibited cytotoxicity towards some cancer cells, while enhancing the growth and viability of the normal cells which were examined.

Adenocarcinoma↗

PubMed1999

Effects of acupuncture on the levels of endothelin, TXB2, and 6-keto-PGF1 alpha in apoplexy patients.

In order to delve into the mechanism governing the treatment of apoplexy by acupuncture at yangming channel points as main points, we observed the changes in the endothelin (ET) level in plasma, TXB2 and 6-Keto-PGF1 alpha levels in urine in convalescent apoplexy patients during acupuncture treatment. The results showed that the ET level in plasma in convalescent apoplexy patients was significantly higher than that in healthy subjects (P < 0.05), and the ET level in plasma in patients was decreased after one course of acupuncture treatment. It was found that before treatment the TXB2 level in urine in apoplexy patients was significantly higher than in healthy subjects, and the 6-Keto-PGF1 alpha level in urine in the patients was significantly lower than that in healthy subjects, with an increased ratio of TXB2 to 6-Keto-PGF1 alpha. After acupuncture treatment, the TXB2 level in urine was lowered with a decrease in the ratio of TXB2 to 6-Keto-PGF1 alpha. All this indicated that one of the mechanisms governing acupuncture treatment of apoplexy acupuncture at yangming channel points as main points was that acupuncture could produce therapeutic effects by adjusting the imbalance of important vaso-active substances, ET, TXA2, and PGI2.

6-Ketoprostaglandin F1 alpha↗

PubMed1999

Social support and depressed mood: a structural analysis.

Current literature on social support identifies social structure as a source of distress. However, past efforts tend to operationalize structure in terms of demographic characteristics. The present paper argues that structure should be conceived of as participation and involvement in community and social relations. Structure may include community ties, social networks and intimate ties. We hypothesize that the three elements represent the outer layer (belongingness), the intermediary layer (bonding), and the inner layer (binding) of social relations and should exhibit differentiated effects on mental health. We further hypothesize that these structural elements, in sequence, provide functional (i.e., instrumental-expressive, perceived-received, and routine-non-routine) supports which, in turn, prevent or protect against distress. Using data from the 1993-1994 Albany survey, we construct measures for elements of structural and functional support to test the relationship between the two as well as their effects on depression. Results confirm that elements of structural support, as predicted, differentially affect functional supports, and that the elements of both structural and functional supports exert direct effects on depression. Further, structural supports also exert indirect effects on depression, mediated by functional supports.

Adult↗

PubMed1999

[The proper opportunity of surgery for rectal cancer after preoperative adjuvant chemotherapy].

OBJECTIVE: To discuss the proper opportunity of surgery for rectal cancer after preoperative intra-arterial chemotherapy. METHODS: Preoperative chemotherapy was performed on 27 rectal cancer cases at Dukes stage B and C. The therapy comprised of arterial infusion of 5-fluorouracil 600 mg/m(2), mitomycin 15 mg/m(2) and epirubicin 30 mg/m(2) for one course. Miles' or Dixon's operation was carried out 7 to 10 days later. The effects of chemotherapy were evaluated. Dynamic changes of proliferating cell nuclear antigen (PCNA) expression were studied by immunohistochemistry on paraffin-embedded sections. RESULTS: Hematochezia was remitted in 19 cases. Histologically, the effects of chemotherapy were considered as slight, moderate and marked in 9, 15 and 3 cases, respectively. Side effects were slight and recovered in 4 days. There was a high expression of PCNA in rectal cancer. On the 7th to the 10th day, proliferating index was significantly higher than that of before chemotherapy (46.48 +/- 10.62)%, P < 0.05. CONCLUSIONS: Preoperative adjuvant chemotherapy plays a role in the treatment of resectable rectal cancer. It is suggested that radical surgery should be carried out 5 to 6 days after intra-arterial chemotherapy.

Adult↗

PubMed1999

[The correlation of free radicals induced by cadmium toxicess with erythrocyte injury and band3 expression].

OBJECTIVE: To study the correlation of hydrogen peroxide induced by cadmium ion with erythrocyte injury and band3 expression. METHODS: It was application immunoscanning electronmicroscopy and cytochemistry and EDX methods. RESULT: Cadmium ion not only induced a lot of hydrogen peroxide but also caused serious distortion of erythrocyte. CONCLUSION: Cadmium ion-induced free radicals lead to oxygen free radical damage of membrane and crytoskelecton of erythrocyte, affecting the stability and deformability and band3 expression in erythrocyte.

Animals↗

PubMed1999

[Application of cerium cytochemical method in observation of renal injury caused by oxygen free radical with cadmium induction].

OBJECTIVE: To study acute renal injury caused by oxygen free radical with cadmium induction. METHODS: Electron microscopy cytochemical and energy dispersive X-ray (EDX) analysis techniques were used. RESULTS: Cadmium ions could enter the epithelial cells of renal proximal convoluted tubules. Excessive production of oxygen free radical was found in the kidney tissues, which located mainly in the endothelial cells of blood vessels, mitochondria of epithelial cells of renal proximal convoluted tubules, microvilli and basement membrane. Swelling of epithelial cells and mitochondria and drop of epithelial cells could occur in renal proximal convoluted tubules. CONCLUSION: It suggests that cadmium ions can induce the formation of large amount of oxygen free radical and cause renal injury.

Acute Kidney Injury↗

PubMed1999

[Experience of endoscopic sinus operation on 74 cases].

OBJECTIVE: To improve the curative effect of endoscopic sinus operation. METHOD: The clinical data of nasal cavity and nasal sinus via endoscopic sinus operation on 74 cases (115 sides) were in summary. Of those 74 cases, 65 were followed-up over six mothes. RESULT: It showed that 44 cases were cured, 18 were improved, 3 were ineffective. The effective rate was 95.4%. The disappearance rate of four symptons-nasal obstruction, headache, purulent nasal discharge and loss of smelling was 95.2%, 92%, 66.7% and 42.5%, respectively. The serious operative complication was absent. CONCLUSION: It helped to raise thd effect of anesthetization to apply nasal cavity surface anesthesia, nerve block anesthesia. Paying attention to the distinguish of dissection label can help to decrease the occurance of the serious complication of the sinus ethmoidal operation. The operation which was alternatively conducted between endoscope and cavascope, according to the operation requirement, can be carried out more thoroughly and more safely. Cleaning the operation cavity after operation can promote healing.

Adult↗

PubMed1999

[One-stage reconstruction with the pedicle skin flap of forehead for defective tissue of head-neck tumors dissection].

OBJECTIVE: To discuss the feasibility on reconstructing the defective tissue with the pedicle skin flap of forhead after head-neck tumors dissection. METHOD: 14 patients with advanced head-neck tumors were studied, whose defective tissues were reconstructed by their forehead skin flaps. The flap area ranged from 5 cm x 11 cm to 7 cm x 16 cm. RESULT: 2 cases of them were partial necrosis, 3 years and 5 years survival rates were 76.9% and 63.6% respectively. The function of breath through nose or mouth and the function of swallow were satisfactory. CONCLUSION: The forehead skin flap should be a good selection for the reconstruction of defective tissue after basicranial and nasalfacial dissection.

Adolescent↗