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Biomedical subjects

F Wu

Publications and source records attributed to F Wu.

At least 127 records · Page 7Linked to original sources
PubMed1998

[Induction of apoptosis of CD34+ cells by serum from two patients with severe aplastic anemia].

OBJECTIVE: To explore the relationship between the hematopoietic inhibitor and apoptosis of CD34+ cells in patients with severe aplastic anemia (SAA). METHODS: The inhibiting activity to the growth of both BFU-E and CFU-GM was analysed by in vitro methylcellulose culture and CD34+ cell apoptosis was assayed with a kit of programmed cell death assay and flow cytometry. RESULTS: Sera from two SAA patients suppressed the growth of normal hematopoietic progenitor cells and induced CD34+ cell apoptosis. Serum immunoglobulin fraction assay showed that the inhibiting activity was in the IgG fraction which bound specifically to CD34+ cells. CONCLUSION: There was an inhibitive IgG fraction, which induced CD34+ cell apoptosis, in the serum of SAA patients and CD34+ cell apoptosis might be a part of the pathogenesis of SAA.

Adolescent↗
PubMed1998

[Comparative study on the effect of gossypol and T7 on human spermatozoa ATPase activity].

OBJECTIVE: A comparative study was carried out on the effect of two kinds of male contraceptive drugs, gossypol and the abstract of tripterygium wilfordii T7, on the human spermatozoa ATPase activity. METHODS: The specific activity of total ATPase and Na-K ATPase of spermatozoa was assayed in this experiment. RESULTS: (1) The effect of gossypol on the human spermatozoa ATPase activity is inhibitory and concentration-dependent; and (2) The abstract of tripterygium wilfodii T7 has no effect on the human spermatozoa ATPase activity. CONCLUSIONS: The antifertility effects of gossypol and T7 are different.

Adenosine Triphosphatases↗
PubMed1998

[The chemical constituents of Goniothalamus howii Merr].

Two new compounds were isolated from the chloroform soluble fraction of ethanolic extract of bark of Goniothalamus howii Merr. On the basis of their chemical properties and spectral data (MS, UV, IR, 1H and 13CNMR) they were identified as 6S (1R-hydroxy-2R-cinnamyloxyphenethyl) 5, 6-dihydro-5S-hydroxy-2-pyrone named Howiinol A and 6S-(1S, 2R-epoxyphenethyl-5S-cinnamyloxy) 5, 6-dihydro-2-pyrone named Howiinin A. Howiinol A showed significant antitumor activities toward human tumor cell in vitro and in vivo and less toxic.

Animals↗
PubMed1998

[The transfection and morphological changes of human embryonic nasopharyngeal epithelia infected by Epstein-Barr virus cooperated with promoter in vitro and in vivo].

In order to detect the ability of EBV on transfecting and transforming human nasopharyngeal epithelia(HNE) isolated from human embryo, the HNE was cultured in vitro and then transplanted into nude mice. HNEs were treated by EBV, EBV + TPA and TPA in vitro, respectively. The mice transplanted with HNE tissues were injected subdermally by EBV, EBV + TPA and distilled water several times, respectively. The morphological changes indicated that EBV induced not only enhancement of foci and N/C ratio in cultured HNE which are important characteristics of malignant transformation, but also carcinogenesis of transplanted HNE, all of the carcinoma were EBV positive. TPA seems to increase EBV transfection rate (EBV PCR positive rate) in vitro, especially in the early stage. TPA alone did not exert effect on malignant transformation Cooperating with TPA, EBV induced early invasive carcinoma in vivo.

Animals↗
PubMed1998

Distribution of thioltransferase (glutaredoxin) in ocular tissues.

PURPOSE: A new redox regulating enzyme, thioltransferase (TTase), has been found in the lens. The authors investigated whether TTase is also present in other ocular tissues. METHODS: Fresh enucleated bovine eyes were obtained from a local abattoir 4 hours after death. The eyes were processed immediately to remove corneal epithelial cells, conjunctiva, corneal endothelial cells, iris, ciliary body, lens epithelial cells, vitreous body, and retina. Other than conjunctiva and vitreous body, which were collected from a single eye, all other tissues were pooled from three bovine eyes. Each sample was homogenized in 0.1 M phosphate buffer, pH 7.4, and centrifuged at 10,000 g for 20 minutes, and the supernatant was assayed for TTase activity. Total RNA from each tissue sample was extracted and used for slot blot hybridization using cDNA from pig liver TTase with beta-actin as control. RESULTS: Among all the ocular tissues tested, iris showed the highest TTase activity (35 mU/mg protein) followed by conjunctiva, corneal epithelial cells, and corneal endothelial cells. Ciliary body, lens epithelial cells, and retina had moderate activity. No activity could be detected in vitreous body. The presence of this enzyme transcript in these ocular tissues was further confirmed by the positive slot blot hybridization with the pig liver TTase cDNA. Here again, iris showed the highest TTase mRNA expression, followed by ciliary body, lens epithelial cells, corneal endothelial cells, conjunctiva, retina, and corneal epithelial cells. The whole lens showed the lowest TTase mRNA expression, and no TTase mRNA was found in the vitreous body. CONCLUSIONS: TTase was found in most ocular tissues and was concentrated in the anterior segment of the eye. Highest activity was found in the iris, conjunctiva, corneal epithelial, and endothelial cells. TTase was absent in the vitreous body.

Animals↗
PubMed1998

In vitro and animal validation of bromine-76-bromodeoxyuridine as a proliferation marker.

UNLABELLED: The potential of 76Br-bromodeoxyuridine as a PET tracer for characterizing proliferation potential was investigated in multicellular tumor aggregates and in healthy rats and pigs. METHODS: Bromine-76-bromide was produced by proton irradiation of a 76Se-enriched target using a 17-MeV cyclotron and recovered by thermal diffusion. Bromine-76-BrdU was prepared from the corresponding trimethylstannate by an oxidative bromination. Multicellular aggregates from a carcinoid cell line and two bladder cancer cell lines were co-incubated with 76Br-BrdU and 3H-thymidine and the uptake and DNA incorporation analyzed. About 0.5 MBq 76Br-BrdU were injected in the tail vein of unanaesthetised Sprague-Dawley rats. Two to 36 hr later they were decapitated and the radioactivity concentration and fraction of radioactivity incorporated into DNA determined in five different organs and the blood. Parallel studies were performed in animals pretreated with hydroxyurea. In separate experiments, rats were given an injection of 76Br-bromide and organ uptake was evaluated after 20 hr. PET studies were performed in two pigs and the uptake in different organs was investigated after injection of 76Br-BrdU. In these studies, diuresis was induced by furosemide and mannitol and radioactivity in blood and organs was followed during 10 hr. RESULTS: In the cell aggregates, 30%-90% of the radioactivity was extracted in the DNA fraction. A good correlation was found between 76Br-BrdU and 3H-thymidine with respect to total uptake and DNA fraction. The DNA fraction increased from 2-10 hr after incubation. With in vivo injection in the rat, relatively high uptake of radioactivity was found in all organs, unrelated to the degree of DNA synthesis. However, inhibition by hydroxyurea occurred only in the spleen and intestines, organs which also showed a high degree of incorporation of 76Br-BrdU into DNA. In the pig, the highest in vivo uptake was observed in the red bone marrow and the intestines. In these organs, 70%-80% of the radioactivity was recovered in the DNA fraction. The concentration of radioactivity in the heart, liver and kidney was 3-10 times lower, and here the DNA fraction accounted for 10%-20% of the radioactivity. The decay-corrected radioactivity in blood and nonproliferating organs decreased with diuresis with a half-life of 13 and 16 hr, respectively. CONCLUSION: It is suggested that the radioactivity uptake as seen after the administration of 76Br-BrdU, is constituted by two parts: one relating to incorporation into DNA and one existing as free 76Br- or metabolites of 76Br-BrdU. If sufficient time has passed, 76Br- dominates other metabolites. A correct assessment of DNA-incorporated radioactivity using PET with 76Br-BrdU is not trivial and can only be made with due correction for 76Br-, using either a complementary investigation after hydroxyurea pretreatment (in animal studies) or a separate 76Br-bromide investigation. Alternatively, the free bromide can be eliminated partially through forced diuresis.

Animals↗
PubMed1997

Telomerase activity and survival of patients with node-positive breast cancer.

BACKGROUND: Shortening of telomeres (specialized structures at the ends of chromosomes) beyond a certain length may signal a cell to stop dividing and to enter senescence. A ribonucleoprotein enzyme, telomerase, is a key component in maintaining telomere length. Because the majority of cancers express telomerase but most normal somatic tissues do not, we measured the level of telomerase expression in primary breast cancer specimens for correlation with traditional prognostic indicators and disease outcome. METHODS: Telomerase activity was measured in frozen human breast cancer specimens by use of the Telomeric Repeat Amplification Protocol (TRAP) assay. The level of telomerase activity was expressed as total product generated (TPG) and was corrected for specimen cellularity by expressing it as a ratio of TPG to the sample's 28S ribosomal RNA content. RESULTS: A preliminary study of 150 breast cancer specimens demonstrated that telomerase activity correlated with the fraction of cells in S phase of the cell cycle (r(sp) = .23). In a larger prognostic study of 398 tumors from patients with lymph node-positive breast cancer, telomerase expression correlated with S-phase fraction, progesterone receptor level, DNA ploidy, and lymph node status. After correcting for sample cellularity, increasing TPG levels were associated with decreased disease-free survival (P = .041) and overall survival (P = .009) of the patients. The telomerase activity level remained strongly predictive of death (P = .027) and marginally predictive of disease recurrence (P = .08) after adjustment for other prognostic factors. All P values are two-sided. CONCLUSIONS: Telomerase activity in human breast cancers is associated with a more aggressive tumor phenotype in patients.

Adult↗
PubMed1997

Advances in quantification and characterization of telomerase activity by the telomeric repeat amplification protocol (TRAP).

The telomeric repeat amplification protocol (TRAP) assay has been used to test telomerase activity in numerous cancer specimens. We describe primers, controls and quantification methods for the TRAP assay to accurately measure the level of telomerase activity in clinical samples. The assay is reliable and reproducible in routine analyses and can be used to estimate the processivity of telomerase activity.

DNA Primers↗
PubMed1997

Site-specific and sensory neuron-dependent increases in postsynaptic glutamate sensitivity accompany serotonin-induced long-term facilitation at Aplysia sensorimotor synapses.

Long-term changes in the efficacy of Aplysia sensory neuron (SN) connections accompany behavioral training or applications with 5-HT. The changes evoked by training or 5-HT include formation of new SN varicosities and transmitter release sites. Because new synapse formation requires proper alignment of presynaptic structures with postsynaptic zones containing a high density of transmitter receptors, we examined whether changes in postsynaptic sensitivity to the presumed SN transmitter (glutamate) were correlated with formation and distribution of new SN varicosities in contact with motor cell L7 in cell culture. The formation of stable SN connections after 4 d in culture did not significantly change overall responses to focal applications of glutamate. However, specific sites along L7's axon apposed to SN varicosities expressed larger responses to glutamate compared with adjacent sites with few SN varicosities. After treatments with 5-HT that evoked long-term changes in both the structure and the function of SN-L7 synaptic interaction, glutamate responses increased selectively at sites along the surface of L7's axon with preexisting or new SN varicosities. Increases in postsynaptic response to glutamate 24 hr after 5-HT treatment required interaction with an SN. These results suggest that new synapse formation between neurons, either with regeneration or after external stimuli that evoke increases in synaptic efficacy, involves site-specific changes in expression of functional neurotransmitter receptors on the postsynaptic cell that is regulated by interaction with the presynaptic neuron.

Animals↗
PubMed1997

Pathway-specific synaptic plasticity: activity-dependent enhancement and suppression of long-term heterosynaptic facilitation at converging inputs on a single target.

To explore mechanisms of long-term, pathway-specific synaptic plasticity, we examined consequences of differential stimulation of Aplysia sensorimotor connections in culture where two sensory neuron (SN) inputs converge on a single target motor cell L7. A single pairing of tetanus in one SN with bath application of 5-HT evoked long-term (24 hr) increase in efficacy of the SN connection given paired stimulation that was comparable in magnitude to the increase in synaptic efficacy evoked with repeated applications of 5-HT. Repeated pairing of tetanus in one SN with applications of 5-HT evoked a significant increase in efficacy of the SN connection given paired stimuli, and significant reduction in facilitation that is normally evoked by repeated applications of 5-HT in the unpaired SN connection. Hyperpolarization of L7 or incubation with APV interfered with both enhancement of facilitation with paired stimulation and suppression of facilitation with unpaired stimulation, but without interfering with long-term facilitation evoked either by repeated applications of 5-HT or by a single pairing. The results suggest that a single connection can undergo at least two forms of activity-dependent, pathway-specific facilitation lasting more than 24 hr. One form, evoked with a single pairing, is initiated and maintained primarily by activity in the presynaptic neuron. The other form, evoked with repeated paired stimuli, requires target-dependent activity that differentially modulates long-term heterosynaptic facilitation at the converging inputs.

2-Amino-5-phosphonovalerate↗
PubMed1997

Liver injury model induced in mice by a cellular immunologic mechanism--study for use in immunopharmacological evaluations.

Various drugs for clinical hepatitis were applied to a new model of liver injury induced in mice by delayed-type hypersensitivity to picryl chloride (PCI-DTH). The hepatoprotective agent, biphenyl dimethyl dicarboxylate showed a remarkable improvement against the elevation of serum transaminase levels as well as the histopathological changes when given during the induction phase but not during the effector phase of DTH reaction. Cyclophosphamide (Cy), an immunosuppressive agent, significantly inhibited the enzymatic elevation given in both induction and effector phases. However, Cy did not affect the sustaining of liver injury 4 weeks after the liver injury eliciting. Moreover, the consecutive administration of prednisolone (Pred), in both induction phase and sustaining process of liver injury, conversely caused a more severe liver damage. Such exacerbation by Pred might be resulted from its toxic action to hepatocytes. As an immunomodulatory and antiinflammatory agent, glycyrrhizin remarkably improved the sustaining process but not the acute phase of the liver injury. Krestin and malotilate also showed an improving effect on the sustaining development of liver injury. These findings that most of above drugs showed an improving action in their respective manner suggest that this model may be useful for the pharmacological evaluation of drugs especially immunomodulating agents for hepatitis.

Acute Disease↗
PubMed1997

Anti-inflammatory activity of the aqueous extract from Rhizoma smilacis glabrae.

Our previous paper has reported that the aqueous extract from Rhizoma smilacis glabrae (RSG) (RSG ext) selectively inhibited the effector phase of delayed-type hypersensitivity (DTH) without suppressing humoral immune response. In the present study, a remarkable inhibitory activity was exhibited by the extract against both primary and secondary hind paw swelling of adjuvant arthritis in rats. RSG ext also significantly reduced the inflammatory edema induced by carrageenan in either naive or bilaterally adrenalectomized rats, suggesting the independence of the anti-inflammatory action on the function of pituitary-adrenal axis. The PGE2 content in the carrageenan-induced inflammatory tissue was also decreased remarkably by the extract. Furthermore, RSG ext showed a distinct inhibition on the formation of cotton-induced granuloma formation. However, as compared with a steroidal agent, prednisolone, the extract did not affect the vitamin C content in adrenal gland as well as the weights of some organs. These results suggest that RSG ext may act as a therapeutic agent of immunoinflammatory diseases through a selective suppression on the cellular immune response involved in inflammations as well as through a direct anti-inflammatory mechanism including inhibiting PGE2.

Adrenal Glands↗
PubMed1997

A new strategy for regulating the immunological liver injury--effectiveness of DTH-inhibiting agents on DTH-induced liver injury to picryl chloride.

Aqueous extracts from various crude drugs showing a selective inhibition on the induction or effector phase of delayed-type hypersensitivity (DTH) reaction were applied to the new model of liver injury induced in mice by picryl chloride(PCl)-induced DTH. The inhibiting drugs to the induction phase of DTH, Fructus Triburi (FT) and Er-Miao-San (EMS), showed a remarkable improvement against the elevation in serum transaminase levels as well as in histopathological changes when given during this phase. The administration in the effector phase by Rhizoma Smilacis Glabrae (RSG) and Cortex Dictamni (CD), selectively inhibiting the phase of DTH, also significantly improved the liver damage. In addition, RSG and CD showed an almost complete recovery of serum alkaline phosphatase from a persistent decrease in the sustaining process of liver injury when given consecutively for 4 weeks after the elicitation of liver injury. Cyclophosphamide, an immunosuppressive agent, significantly inhibited the enzymatic elevation given in either phase, while it did not affect the ability to sustain liver injury. When the above extracts were given in a combined manner to the same mouse during these two phases, respectively, FT with RSG and EMS with CD showed a distinct synergism against the liver injury. RSG or CD also enhanced the activity of prednisolone in suppressing PCl-induced ear contact sensitivity. These findings suggest that this immunological liver injury may be regulated by a set of selective suppressants to DTH reaction and the suitable application of such agents may pave the way for a new strategy in treating liver damage.

Animals↗
PubMed1997

One-shot delayed-type hypersensitivity reaction in the mouse liver causes a sustained liver injury to picryl chloride.

The developmental characteristics of liver injury induced by a delayed-type hypersensitivity (DTH) mechanism against picryl chloride were examined for 9 consecutive weeks in 3 mouse strains, BALB/c, Kunming and ICR mice. The changes of most biochemical parameters were similar in these three strains, namely, the activities of serum transaminases, lactic dehydrogenase, and prolidase were elevated significantly on day 1, during the first several weeks, and almost throughout the duration, respectively, of liver injury. The content of liver hydroxyproline was also increased after 1-9 weeks of liver injury. In addition, a significant decrease of liver weight, serum alkaline phosphatase and albumin level was observed in BALB/c and Kunming mice. Similar changes in liver histology were also found in the three strains. The hepatocellular necrosis and inflammatory infiltration into the portal area were the predominant features on day 1 and were still distinct during the subsequent several weeks. The mild or moderate hepatocellular degeneration, regeneration and connective tissue hyperplasia were observed after 1 or 3 weeks. A bridging necrosis between portal and portal was observed in several BALB/c and ICR mice, reflecting the possibility of exacerbation of liver injury. These results suggest that the liver injury could be caused and sustained by a one-shot DTH reaction to picryl chloride. The chronicity of the biochemical and histopathological characteristics may be helpful in elucidating the mechanisms of chronic development of liver injury.

Animals↗
PubMed1997

Targeted damage effects of high intensity focused ultrasound (HIFU) on liver tissues of Guizhou Province miniswine.

HIFU can pass through tissues and accurately damage target tissues inside organisms. This article reports on the oriented damage effects of HIFU upon miniswine internal and external liver tissues, and suggests a new conception of the 'biological focal field'. The results revealed that: (1) HIFU can be used to damage accurately liver tissues under the guide of a B-modal ultrasound device; (2) the scope of the injury is connected with sound intensity and irradiation time; and (3) the different layers of tissue through which the ultrasound has passed remain undamaged.

Animals↗
PubMed1997

Epidemiological and clinical studies on an outbreak of trichinosis in central China.

An outbreak of trichinosis occurred in the city of Zhengzhou, central China, between December 1995 and February 1996, affecting 85 of the administrative units into which the city is split. Of 297 subjects from eight of the affected units, 54% were seropositive for Trichinella and 41% had symptoms consistent with acute trichinosis. Of the 490 subjects who had eaten at one particular dumpling restaurant 1-5 weeks before the outbreak and who were traced, 291 (59%) were seropositive and 212 (43%) had been or were ill. MOst of the infections were in manual workers, cadres and merchants aged 20-49 years. Most of those who had been infected failed to develop gastro-intestinal symptoms or a cutaneous rash. Eyelid oedema was only seen in the early stages of the infection, the main clinical manifestations being fever of long duration of tiredness. Surprisingly, six cases had no marked symptoms after repeated infection. Eosinophilia (eosinophils > 7% of leucocytes) was noted in 71 (55%) of the 130 cases in which blood cells were counted. When 212 sera were tested for antibodies to Trichinella, seropositivities were found to increase from 89.1% (IFAT) of 87.7% (microprecipitation test) at presentation to 100% (both tests) 1 week after treatment with albendazole. All those treated were cured. The outbreak was one of the most extensive, single-source outbreaks ever recorded in China, probably with > 600 infections and > 300 clinical cases. The entire episode was attributed to the ingestion of undercooked pork dumplings at one restaurant.

Adolescent↗
PubMed1997

Hyperoxia inhibits fetal rat lung fibroblast proliferation and expression of procollagens.

The direct effects of hyperoxia on collagen production by fetal lung fibroblasts are unknown and would be important to the understanding of the molecular mechanisms involved in bronchopulmonary dysplasia in premature infants. We studied the effect of hyperoxia on 1) proliferation, 2) mRNA levels for type I and III procollagens, and 3) net collagen production in primary cultures of fetal rat lung fibroblasts. Fibroblasts from 19-day-old rat fetuses (term is 22 days) were obtained. Test plates were incubated in hyperoxia and controls in room air for varying time periods. Cell viability in both conditions was >97% as determined by trypan blue exclusion. Fibroblast proliferation in nonconfluent cultures was found to be significantly reduced with exposure to hyperoxia (P < 0.001). Steady-state levels of type I and III procollagen mRNAs, analyzed on Northern blots hybridized to [32P]cDNA probes, were significantly decreased in hyperoxia (P < 0.01). This effect was noted as early as 4 h of exposure to hyperoxia and persisted for 5 days. There was a significant inverse correlation between duration of exposure to O2 and steady-state levels of mRNA for alpha1(I)-procollagen (r = -0.904) and alpha1(III)-procollagen (r = -0.971). There were no significant changes in steady-state levels of beta-actin mRNA. We also found a significant decrease in collagen synthesis in hyperoxia-exposed fibroblasts (P < 0.05). We conclude that hyperoxia directly effects a reduction in fetal lung fibroblast proliferation and net collagen production at a pretranslational level.

Animals↗