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Biomedical subjects

F Zhou

Publications and source records attributed to F Zhou.

At least 73 records · Page 4Linked to original sources
PubMed1999

Apoptosis induced by oxysterol in CEM cells is associated with negative regulation of c-myc.

Previously we have demonstrated that treatment of the human lymphoblastic leukemic CEM cells with 25-hydroxycholesterol (25OHC) induces apoptosis. In the present study, we show that both c-myc mRNA and c-Myc protein levels are reduced only in oxysterol-sensitive and not in oxysterol-resistant cells after treatment with concentrations of 25OHC that kill the sensitive CEM cells. The repression of c-Myc protein precedes c-myc mRNA reduction, and both events occur before the onset of cell death. Our data suggest that 25OHC-induced suppression of c-myc gene expression in CEM cells results from posttranscriptional regulation. These results demonstrate the regulation by an oxysterol of a gene/gene product important for cell growth and viability and an association between oxysterol-induced apoptosis of CEM cells and the negative regulation of c-myc.

Apoptosis↗
PubMed1999

Brain TXA(2)and PGI(2)levels related to diffuse brain injury with secondary insults.

Secondary insults such as hypotension and hypoxia with head injury are associated with increased mortality and morbidity in comparison with head injury alone. In the present study the changes of brain thromboxane A(2)(TXA(2)) and prostacyclin (PGI(2)) levels in a Marmarou's rodent model of diffuse brain injury with hypotension and hypoxia were observed and the effect of diaspirin cross linked haemoglobin solution (DCLHb) were also investigated. Thirty-two male Sprague-Dawley (SD) rats were randomized into four groups: sham; head injury alone; head injury with secondary insults; and injury with insults followed by DCLHb administration. The results showed that there were no changes in TXB(2)and 6-keto-PFG(1a)(metabolites of TXA(2)and PGI(2)) levels in the injury alone group, while TXB(2)levels in the secondary insults group were elevated significantly; both TXB(2)and 6-keto-PGF(1a)levels in the injury with insults followed by DCLHb administration group were augmented significantly in comparison with the corresponding value of sham at 4 postimpact. The only increase in TXA(2)levels in the secondary insults rats suggests that an imbalance in TXA(2)-PGI(2)production contributes to the traumatic secondary processes, which include ischaemia and oedema. It is hypothesized that DCLHb may exert its protective properties through increasing PGI(2)production in injured brain by improving blood supply to injured blood vessels. Copyright 1999 Harcourt Publishers Ltd.

Journal Article↗
PubMed1999

Increased injury following intermittent fetal hypoxia-reoxygenation is associated with increased free radical production in fetal rabbit brain.

Hypoxia associated with perinatal events can result in brain damage in the neonate. In labor and eclampsia, hypoxia can be intermittent, which may result in more severe damage than sustained hypoxia. The pathogenesis of brain injury in sustained ischemia involves free radical production; therefore, we investigated whether higher levels of free radicals contribute to the greater injury induced by repetitive ischemia. Brains were obtained from fetuses of near-term, pregnant rabbits subjected to repetitive ischemia-reperfusion (RIR), sustained uterine ischemia-reperfusion (IR), or a control protocol. Compared with controls, fetal brains from RIR or IR groups had more brain edema. Brains from RIR fetuses exhibited higher levels of lipid peroxidation, 3-nitrotyrosine, and nitrogen oxides, and lower total antioxidant capacity and cortical cellular viability than those of IR or control fetuses. Maternal administration of antioxidants following RIR and fetal bradycardia resulted in lower levels of fetal cortical and hippocampal cell death. Coadministration of Trolox and ascorbic acid resulted in less brain edema and liquefaction, and fewer hippocampal ischemic nuclei as compared with the saline control. Higher free radical production may be responsible for the greater fetal brain injury following repetitive hypoxia-reoxygenation. Maternal antioxidant treatment resulted in transplacental passage of antioxidants and amelioration of brain injury, and may be a viable clinical option following diagnosis of fetal distress.

Animals↗
PubMed1999

[Comparison of endometrial histology and ultrastructure during different ovarian stimulation protocols in hamsters].

OBJECTIVE: To evaluate the influence of ovarian stimulation by pregnant mare's serum gonadotropin(PMSG) with or without gonadotropin releasing hormone agonist (GnRH-a) on endometrial histology and ultrastructure in hamsters. METHODS: Thirty hamsters were randomly allocated into 3 groups. (1) LA + PMSG group: Leuprolide acetate (LA) was given first for desensitizing the pituitary, then PMSG added for ovarian stimulation. (2) PMSG group was injected with PMSG only. (3) Control group was given with saline of same volume as groups LA + PMSG and PMSG on the same time schedule. Endometrial histology and ultrastructure were investigated by light microscope and electron microscope. RESULTS: Comparing to the controls, the changes of endometrial histology in group of LA + PMSG was not significantly different, but its ultrastructure had marked atterations: mitochondria swelling, undifferentiated crista and no basket-like structure. Delayed endometrial maturation was frequently found in group PMSG (P < 0.01), and the ultrastructure showed poorly developed mitochondria. CONCLUSION: The degree of endometrial maturation varied considerably with different ovarian stimulation protocols. Ovarian stimulation with GnRH-a was better than PMSG alone, because the protocol LA + PMSG, in hamsters, facilitated the formation of a physiologic endometrium. But the protocol with GnRH-a still had a negative effect on endometrial ultrastructure.

Animals↗
PubMed1999

[Analyses of the factors affecting the occurrence of polypronuclear embryos in in-vitro fertilization and embryo transfer].

OBJECTIVE: To investigate the factors affecting the occurrences of the polypronuclear embryos in in-vitro fertilization and embryo transfer (IVF-ET). METHODS: The data from 145 IVF-ET cycles and 1,168 oocytes were analyzed by logistic regression for multiple factors. The influences of the couple's age, the superovulation stimulation protocols, the number of the follicles punctured and the oocytes obtained, the preinseminational interval, the quality and quantity of seminal and inseminational sperms, and the oocyte fertilization ratio on the incidences of the polypronuclear embryos from the matured, and immature oocytes were examined respectively. RESULTS: The incidence of the polypronuclear embryos from matured oocytes was significantly negatively correlated with the women age and the number of the follicles punctured, and the incidence from immature oocytes was significantly positively correlated with the density of sperms at grade a and b and the oocyte fertilization ratio. CONCLUSIONS: The woman's age and the number of follicles are the main factors which influence the occurrence of polypronuclear embryos from matured oocytes, while the density of the seminal sperm with high motility and the fertilization ratio play important roles in the occurrence of polypronuclear embryos in immature oocytes. Stimulating greater number of follicles might be benefit for the reduction of occurrence of polypronuclear embryos.

Embryo Transfer↗
PubMed1999

[Relationship of nitric oxide and immunal function of the patients with acute hepatitis and hepatic cirrhosis].

The interleukin-12(IL-12), interleukin-10(IL-10), tumor necrosis factor(TNF) and nitric oxide (NO) levels in serum of 90 patients with hepatitis and cirrhosis were measured by the method of ELISA and colorimeter. The levels of IL-12, IL-10 and NO in serum of the patients with hepatitis were in close proximity to the level of healthy control, but the TNF level was significantly higher than that of healthy control. The IL-12, IL-10, TNF and NO levels in serum of the patients of hepatic cirrhosis were significantly higher than that of healthy control and patients with hepatitis. The results suggested that the NO level was not related with the hepatic damage of acute hepatitis. The dysfunction of immunology in the patients with cirrhosis was related with the increase of NO level.

Adult↗
PubMed1999

[Compression of the deep branch of ulnar nerve at the wrist].

OBJECTIVE: To investigate the compression factor and clinical manifestation of the compression of deep branch of the ulnar nerve at the wrist. METHODS: Anatomic study was done on both sides of 10 cadavers, the deep branch of ulnar nerve, the Guyon's canal and the flexor digiti minimi brevis pedis were observed. Then from Jan. 1990 to Jan. 1997, 5 patients with compression of the deep branch of ulnar nerve at the wrist were treated clinically. Among them, there were 4 males and 1 female, aged from 37 to 48 years and the course of disease ranged from 1 to 5 months. RESULTS: The motor branch of the ulnar nerve passed under the tendinous arcade of flexor digiti minimi brevis pedis. Occasionally, the branch of ulnar artery overpassed the motor branch. Clinically, the tendinous arcade compressed the motor branch was released, and after 2 to 4 years follow-up, the clinical results were satisfactory. CONCLUSION: The main compression factor of the ulnar nerve at the wrist is the tendinous arcade of the flexor digiti minimi brevis pedis, the tendinous arcade should be released sufficiently during the operation.

Adult↗
PubMed1999

[Pollen morphology identification of five species of medicinal sanguisorba with electron microscope].

OBJECTIVE: To approach a new evidence for identifying various species of Rosaceae Sanguisorba, especially for distinguishing S. applanata from S. sitchinese. METHOD: The pollens of five species S. officinalis, S. officinalis var. longifolia, S. applanata, S. applanata var. villosa and S. sitchinese were morphologically identified with electron microscope. RESULTS: The pollens are prolate or perprolate, having six colporates and featuring sculptures of small caverns and small granules combined. The species are closed to each other in pollen morphology, bur display differences in the diameter of pollens, clarity of pore membrane and presence or absence of irregular verrucous sculptures. CONCLUSION: This paper provides a new evidence for identifying the Sanguisorba.

Microscopy, Electron, Scanning↗
PubMed1999

[Immunohistochemical detection of hepatitis C virus antigen from hepatocellular carcinoma].

To investigate the infection of HCV and the expression of HCV antigen (HCAg) in HCC, immunohistochemical protocol was performed on tumorous liver tissues from 40 patients with HCC to detect HCAg and hepatitis B virus surface antigen (HBsAg) simultaneously. The results showed that the positive rates for HCAg and HBsAg were 17.5% (7/40) and 70% (28/40) respectively. HBsAg and HCAg were simultaneously detected in six of 40 cases and only one case had HCAg positive alone in the liver tumorous tissue. The positive signals were localized in diffuse cytoplasm of hepatocytes and the positively stained cells were mainly distributed in local pattern. The results suggested that HCV infection did exist in some cases of HCC, so HCV might be a viral risk factor in addition to HBV in the genesis of HCC in China.

Adult↗
PubMed1999

[Quantitative determination of cholic acid in Calulus Bovis].

OBJECTIVE: To establish a method to determine the Content of cholic acid in Calulus Bovis. METHOD: The content was determined by TLCS. RESULT: Recovery rate was 96.54%, RSD was 1.68%. CONCLUSION: Accurate and reproducible, this method can be used for the quality control of Calulus Bovis.

Animals↗
PubMed1998

Tetranucleotide GGGA motif in primary RNA transcripts. Novel target site for antisense design.

Selecting effective antisense target sites on a given mRNA molecule constitutes a major problem in antisense therapeutics. By trial-and-error, only 1 in 18 (6%) of antisense oligonucleotides designed to target the primary RNA transcript of tumor necrosis factor-alpha (TNF-alpha) strongly inhibited TNF-alpha synthesis. Subsequent studies showed that the area in RNA targeted by antisense oligonucleotides could be moved effectively 10-15 bases in either direction from the original area. We observed that only molecules that incorporated a tetranucleotide motif TCCC (complementary to GGGA on RNA) yielded potent antisense oligonucleotides against TNF-alpha. A comprehensive literature survey showed that this motif is unwittingly present in 48% of the most potent antisense oligonucleotides reported in the literature. This finding was prospectively used to predict the sequences of additional antisense oligonucleotides for the rat TNF-alpha primary RNA transcript. Over 50% of antisense constructs (13 of 22) containing the TCCC motif were found to effectively inhibit TNF-alpha synthesis. Marked reductions in mRNA were also observed. This motif was found to be most effective when targeting introns in the primary RNA transcript, suggesting a nuclear localization for the antisense action. Predicting target sites based on the presence of this motif in primary RNA transcripts should be of value in the development on new antisense pharmacotherapy.

Animals↗
PubMed1998

Hypoxia-reoxygenation is as damaging as ischemia-reperfusion in the rat liver.

OBJECTIVE: We hypothesized that the extent of injury and release of xanthine oxidase, an oxidant generator, into the circulation would be less in normal-flow hypoxia-reoxygenation than in equal duration no-flow ischemia-reperfusion. DESIGN: Randomized study. SETTING: University-based animal research facility. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: The livers were isolated, perfused, and then randomly subjected to 2 hrs of hypoxia (normal flow, low oxygen) or ischemia (no flow, no oxygen), and 2 hrs of reperfusion. Hepatocytes were also isolated, and were subjected to either: a) hypoxia (0, 2, 4, and 6 hrs); or b) hypoxia (2 and 4 hrs) with reoxygenation (2 hrs). MEASUREMENTS AND MAIN RESULTS: The extent of liver injury (as assessed by release of hepatocellular enzymes) and the release of xanthine oxidase were measured from isolated-perfused rat livers and cultured hepatocytes. The pattern of release of xanthine oxidase in isolated-perfused liver effluent was different in hypoxia-reoxygenation compared with ischemia-reperfusion. During hypoxia, xanthine oxidase gradually increased in the effluent; then, the xanthine oxidase decreased to low concentrations during reoxygenation. After ischemia, there was a sharp spike in xanthine oxidase at 1 min of reperfusion, with a rapid decrease to low concentrations. The total release of xanthine oxidase during hypoxia-reoxygenation was similar to that during ischemia-reperfusion. Lactate dehydrogenase and other markers of liver injury showed a pattern of release that was similar to that of xanthine oxidase, but the total release of markers was not different between the two groups. In hepatocytes, most of the release of enzymes occurred in hypoxia, and the rate of release was not different between hypoxia and hypoxia-reoxygenation. CONCLUSIONS: Hypoxia-reoxygenation results in as much damage to the liver as ischemia-reperfusion, and results in the release of a similar amount of oxidant-producing xanthine oxidase into the circulation.

Alanine Transaminase↗
PubMed1998

Sustained hypoxia-ischemia results in reactive nitrogen and oxygen species production and injury in the premature fetal rabbit brain.

Free radical-mediated injury is implicated in hypoxic-ischemic encephalopathy observed in neonates. We investigated in utero free radical production and injury following hypoxia-ischemia to premature fetal brain utilizing a rabbit model of acute placental insufficiency. Pregnant rabbits at 29 days gestation were randomized to uterine ischemia for 50 minutes (min) (hypoxia) or nonischemic controls. Fetal brains were obtained immediately after ischemia for oxidative and acute-injury markers or 24 hours (h) post-ischemia for histopathology. Nitrotyrosine formation, a marker of NO-derived species such as peroxynitrite, was observed only in hypoxic brains. Hypoxia resulted in a significant increase in nitrogen oxides, lipid peroxidation, and protein oxidation, with a concomitant decrease in total antioxidant capacity, compared with controls. Peroxynitrite addition to brain homogenate increased nitrogen oxides linearly (1:1), although protein carbonyls were unchanged. Concomitantly, in vitro cortical and hippocampal cell viability and ATP levels decreased, with an increase in brain edema in hypoxic brains. Fetuses delivered 24 h post-ischemia had increased hippocampal nuclear karyorrhexis on histology compared with controls. Antioxidant administration (ascorbic acid and Trolox) intraperitoneally ameliorated changes in cellular viability and brain edema. Acute fetal hypoxia-ischemia without reoxygenation results in increased nitrogen and oxygen free radical production that may cause brain injury. The merits of the described model are discussed.

Animals↗
PubMed1998

Molecular characterization of the oxalate oxidase involved in the response of barley to the powdery mildew fungus.

Previously we reported that oxalate oxidase activity increases in extracts of barley (Hordeum vulgare) leaves in response to the powdery mildew fungus (Blumeria [syn. Erysiphe] graminis f.sp. hordei) and proposed this as a source of H2O2 during plant-pathogen interactions. In this paper we show that the N terminus of the major pathogen-response oxalate oxidase has a high degree of sequence identity to previously characterized germin-like oxalate oxidases. Two cDNAs were isolated, pHvOxOa, which represents this major enzyme, and pHvOxOb', representing a closely related enzyme. Our data suggest the presence of only two oxalate oxidase genes in the barley genome, i.e. a gene encoding HvOxOa, which possibly exists in several copies, and a single-copy gene encoding HvOxOb. The use of 3' end gene-specific probes has allowed us to demonstrate that the HvOxOa transcript accumulates to 6 times the level of the HvOxOb transcript in response to the powdery mildew fungus. The transcripts were detected in both compatible and incompatible interactions with a similar accumulation pattern. The oxalate oxidase is found exclusively in the leaf mesophyll, where it is cell wall located. A model for a signal transduction pathway in which oxalate oxidase plays a central role is proposed for the regulation of the hypersensitive response.

Amino Acid Sequence↗
PubMed1998

Optimization of the processing of matrix pellets based on the combination of waxes and starch using experimental design.

An experimental design was used in order to optimize the one-step production process of matrix pellets based on the combination of waxes and starch. The parameters tested were the impeller speed (x1) and the mixing time (x2). Ibuprofen and theophylline were used as model drugs at a concentration of 60 and 70% (w/w), respectively. The 0.8-1.25 mm yield fraction of the matrix pellets was evaluated as the response factor Y. A quadratic equation was fitted to the experimental data and used to predict the response factor Y of the theophylline and the ibuprofen. The contour plots of both formulations revealed a flat and therefore rugged region from the upper left to the lower right of the domain investigated. The energy input into the system during the production process controlled the pellet growth, the impeller speed having a greater impact on the energy input compared to the mixing time.

Delayed-Action Preparations↗