Biomedical subjects

X Cai

Publications and source records attributed to X Cai.

At least 55 records · Page 3Linked to original sources

PubMed2001

Inhibition of hepatitis B virus by oxymatrine in vivo.

AIM: To investigate the anti-HBV effect of oxymatrine (oxy) in vivo. METHODS: HBV transgenic mice were produced by micro-injection of a 4.2 kb fragment containing the complete HBV genomes. Expression level of HBsAg and HBcAg in the transgenic mice liver was determined by immunohistochemical assay. RESULTS: Four groups (6 mice in each group) were injected intraperitoneally with oxy at the dosage of 100, 200, and 300 mg/kg or with saline once a day for 30 days. Both HBsAg and HBcAg were positive in livers of all the six mice in the control group (injected with saline), and were positive in livers of two mice in 100mg/kg group and 300 mg/kg group. In 200 mg/kg group, HBsAg and HBcAg were negative in livers of all the six mice. Based on the results, 200mg/kg is the ideal dosage to explore the effect of oxy at different time points. According to the oxy treatment time, mice were divided into four groups: 10 d, 20 d, 30 d and 60 d (4 mice in each group). Each mouse underwent liver biopsy two weeks before the treatment of oxy. Down-regulation of HBsAg and HBcAg appeared after treatment of oxymatrine for 10 d and 20 d, Dane-like particles disappeared after the treatment of oxy for 20 d under electron microscopy, however, the expression level of HBsAg and HBcAg returned to normal 60 d later after oxy treatment. CONCLUSION: Oxymatrine can reduce the contents of HBsAg and HBcAg in transgenic mice liver,longer treatment time and larger dosage do not yield better effects.

Alkaloids↗

PubMed2001

[Effect of five kinds of vegetable seed oil on serum lipid and lipid peroxidation in rats].

The effects of vegetable seed oil on hyperlipidemia induced by high lipid diet in rats. Male adult Wistar rats were fed on the test diet containing 94% high lipid diet and 6% lard pinon seed oil, perilla seed oil, blackcurrent seed oil, borage seed oil and evening primrose seed oil respectively for 3 weeks. The results showed that the vale of trilyceride(TG), total cholesterol(TC), low density lipoprotein cholesterol (LDL-C), LDL-C/HDL-C(high density lipoprotein cholesterol) ratio increased and the vale of HDL-C/TC ratio and lecithin-cholesterol acyltransferase(LCAT) activity decreased in the groups with vegetable seed oil were less than that of the control group. The results suggested that all the five kinds of vegetable seed oil had the effect of regulating lipid metabolism of hyperlipidemia rats to some extent. Pinon seed oil and borage seed oil may be well suited for the prevention of atherosclerosis.

Animals↗

PubMed2001

Water scarcity and food security: alternative futures for the 21st century.

Water availability for agriculture--the major water user worldwide--is one of the most critical factors for food security in many regions of the world. The role of water withdrawals in irrigated agriculture and food security has been receiving substantial attention in recent years. This paper addresses key questions regarding water availability and food security, including: How will water availability and water demand evolve over the next three decades, taking into account availability and variability in water resources, the water supply infrastructure, and irrigation and nonagricultural water demands? What are the relationships among water scarcity, food production, and food security? How much of future food production will come from rainfed and irrigated areas? A global modeling framework, IMPACT-Water, is applied to explore answers to these questions using analysis.

Agriculture↗

PubMed2001

Arsenic trioxide induces multiple myeloma cell apoptosis via disruption of mitochondrial transmembrane potentials and activation of caspase-3.

OBJECTIVE: To investigate the response of multiple myeloma (MM) cells to arsenic trioxide (As2O3) and their possible mechanisms. METHODS: Two MM-derived cell lines RPMI8226 and U266 cells were used as in vitro models. Cell apoptosis was assessed by morphology, flow cytometry, and DNA gel electrophoresis. Mitochondrial transmembrane potentials (delta psi m) were evaluated by measuring cellular Rhodamine 123 staining intensity. Protein expression was analyzed using Western blot. RESULTS: Zero point one to 0.5 mumol/L As2O3 inhibited cell proliferation and 2.0 mumol/L As2O3 induced cell apoptosis, while 1.0 mumol/L As2O3 inhibited proliferation with a weak degree of apoptosis induction in RPMI8226 and U266 cell lines. As2O3-induced apoptosis was accompanied by mitochondrial transmembrane potentials (delta psi m) collapse and caspase-3 activation in the presence of intact membrane. Glutathione depleter buthionine sulfoximine enhanced, while disulfide bond-reducing agent dithiothreitol partially antagonized As2O3-induced delta psi m collapse and apoptosis in MM cells. All-trans retinoic acid (ATRA) could also induce apoptosis in RPMI8226 cells, but it did not show any cooperative effects with As2O3. CONCLUSION: As2O3 exerts apoptosis-inducing and growth-inhibiting effects on MM cells, and mitochondrium is a pivotal and common target of As2O3 for apoptosis induction.

Antineoplastic Agents↗

PubMed2001

Neuronal cdc-2 like kinase in developing kindling rat hippocampus.

OBJECTIVE: To test the hypothesis that neuronal cdc2-like kinase (Cdk5/p35nck5a) plays an important role in neuronal maturation and sprouting. METHODS: Changes kinase activity, expression levels and subcellular localizations of Cdk5 and p35nck5a in the rat hippocampus were studied during kindling progression by Western blot analysis, immunohistochemistry, immunoprecipitation and kinase assay. RESULTS: Kinase activity in kindling rats was significantly higher than that in normal adult rats. The kinase activity at stage 3 was most prominent among all stages of kindling progression. The changes in kinase activity coincided with those of p35nck5a expression in kindling rats. In contrast, the expression of Cdk5 was constant throughout the progression of kindling stages. However, subcellular localization of Cdk5 dramatically changed in the hippocampal neurons of kindling rats. Cdk5 was translocated from axon to soma when kinase activity was high. p35nck5a was always localized in the soma throughout kindling progression. CONCLUSIONS: Neuronal cdc2-like kinase plays an important role in synaptic reorganization, and the translocation of Cdk5 to the soma from the axon may be a novel regulatory mechanism to control kinase activity.

Animals↗

PubMed2001

Intracoronary stent implantation under intracoronary ultrasound guidance with aspirin and ticlopidine therapy.

OBJECTIVE: To observe the immediate angiographic and intravascular ultrasound (IVUS) results and their effects on one month clinical outcomes in forty-one patients who submitted to coronary stent deployment with IVUS guidance. METHODS: All patients were allocated to coronary stent implantation with high inflation pressure. After good angiographic results (< 20% residual stenosis), all patients underwent IVUS and higher-pressure dilatation would be necessary if criteria for optimal coronary stent implantation were not met. The optimal criterion of IVUS for stent implantation was the ratio of intrastent lumen cross-sectional area to the average of the proximal and distal reference lumen cross-sectional areas > or = 80%. All patients had aspirin and ticlopidine therapy on the day of angioplasty and during the one month follow-up period. RESULTS: Optimal criteria of IVUS were obtained without any further intrastent dilatation in twenty-five patients but intrastent higher-pressure dilatation was performed in fourteen patients whose ultrasound results did not reach the criteria. In these patients, we increased the minimal intrastent lumen area 25.7% (P < 0.05). Thirty-five patients (90%) had good minimal intrastent lumen area of IVUS. There were no deaths, myocardial infarction, acute stent thrombosis or need for revascularization during the study and the one month follow-up. CONCLUSIONS: Intracoronary stent deployment under IVUS guidance, including combining aspirin and ticlopidine therapy, had beneficial ultrasound results and good clinical outcomes after one month follow-up.

Aged↗

PubMed2001

Relationship between age and effect of early and long-term captopril treatment in patients with acute myocardial infarction.

OBJECTIVE: To analyse the relationship between age and treatment with captopril after acute myocardial infarction (AMI). METHODS: In a randomized trial, 822 patients with a first AMI received conventional medical treatment, including intravenous thrombolytic therapy and oral aspirin or metoprolol, and then were randomly allocated to captopril [dosage from the first 6.25 mg to 25 mg/t.i.d, 209 younger patients (< or = 64 years), 269 elderly patients (65-75 years)] or conventional treatment only (131 younger patients, 213 elderly). Survival in the four groups was calculated with the Kaplan-Meier method. Multivariate analysis was performed to understand the degree that multi-variables (including age) affect survival in patients taking captopril in the hospital or during long term follow-up. RESULTS: The survival of patients who took captopril correlated significantly with age (P < 0.001). The survival of the elderly patients on captopril treatment did increase (P < 0.0001), but not of the younger ones (P > 0.05) during hospitalization. During follow-up, the survival of patients who took captopril correlated insignificantly with age (P > 0.05), but both the elderly and the younger patients have good survival rates (all P < 0.01) and lower cardiac events (all P < 0.01) when they took captopril. CONCLUSIONS: Captopril exerts a weak effect on the younger patients but a beneficial effect on the elderly patients during hospitalization after AMI. However, there is no difference between the younger and the elderly in the prognosis, both having good survival and lower cardiac events when they take captopril long term during follow-up.

Adult↗

PubMed2001

A novel serine protease SNC19 associated with human colorectal cancer.

OBJECTIVE: To study the structure and function of a novel serine protease gene associated with human colorectal cancer SNC19. METHODS: The cDNA sequence was determined by both manual and automatic sequencing techniques. The full length cDNA sequence was obtained by the 5'-Rapid Amplification of cDNA Ends technique and web-based analysis. Open reading frame analysis and protein function prediction were also performed. Northern blot was used to detect the expression of SNC19 in various human normal tissues and tumor cell lines. Fluorescent in situ hybridization combined with fluorescent R-banding technique was employed to map the SNC19 gene on human chromosome. RESULTS: Full length SNC19 cDNA, size 3152 bp, encodes a protein highly homologous to a mouse serine protease epithin. In normal human tissues, high SNC19 expression levels were observed in the kidney, pancreas, prostate, small intestine and colon; moderate SNC19 expression levels were observed in the placenta, lung, liver, spleen thymus, testis and peripheral blood lymphocytes; and extremely low expression levels were observed in the heart, brain, skeletal muscle and ovary. In tumor cell lines, colorectal cancer cells SW480, SW620, SW1116 and Colo205, breast cancer cell Bcap37 and gastric cancer cells MKN28 and SGC7901 showed high levels of SNC19 expression; cervical cancer cell HeLa-S3, lung cancer PAA, oral epithelial cancer cell KB and lymphoma cell Raji showed moderate levels of SNC19 expression; and tongue squamous cancer cell Tca8113, leukemia cells HL-60, K562, MOLT-4, lung cancer cell A549 and melanoma cell G361 showed very low levels of SNC19 expression. SNC19 was mapped to human chromosome 11q24-25. CONCLUSION: SNC19 encodes a novel human serine protease with 855 amino acid residues. As a novel serine protease associated with human colorectal cancer, the expression of SNC19 in various tissues and cell lines may have very important impact on their phenotypes and biological behaviors.

Amino Acid Sequence↗

PubMed2001

[Mechanisms of arsenic trioxide-induced apoptosis in myeloma cells].

OBJECTIVE: To investigate the possible mechanisms of arsenic trioxide (As2O3)-induced apoptosis in multiple myeloma (MM) cell line, and the interactions between As2O3 and all-trans retinoic acid (ATRA) or interferon(IFN)-alpha. METHODS: Multiple myeloma cell lines RPMI 8226 and U266 were treated with As2O3 in combination with dithiothreitol (DTT), buthionine sulfoximine (BSO), ATRA and IFN-alpha. Cell viability was counted by trypan-blue exclusion. Apoptosis was assessed by cell morphology and flow cytometry. Mitochondrial transmembrane potentials (delta psi m) were measured by cellular rhodamine 123 staining intensity on flow cytometry. RESULTS: Glutathione depleting agent BSO at 1.0 mmol/L enhanced, while disulfide bond-reducing agent DTT at 0.2 mmol/L partially antagonized As2O3-induced decline of delta psi m and apoptosis in MM cells. ATRA also induced RPMI 8226 cell apoptosis, but it could not synergize with As2O3. On the other hand, As2O3-induced apoptosis did not occur in U266 cells. In addition, IFN-alpha itself did not inhibit the growth and viability of MM cells, nor did it influence the effects of As2O3 on MM cells. CONCLUSION: As2O3-induced apoptosis of RPMI 8226 multiple myeloma cells involves sulphyhydryl groups. ATRA and IFN-alpha do not synergize with As2O3 in the induction of apoptosis of MM cells.

Antineoplastic Agents↗

PubMed2001

Clinical application of tentorium cerebelli hiatus incision in treatment of severe and most severe brain injuries.

OBJECTIVE: To explore the role of tentorium cerebelli hiatus incision in treating severe and most severe brain injuries complicated by tentorial herniation. METHODS: From July 1994 to July 1999 tentorium cerebelli hiatus incision was done based on intracranial hematoma evacuation and bone flap craniectomy decompression in 70 cases of severe and most severe brain injuries complicated by tentorial herniation. RESULTS: Of the 70 cases, GCS 3-5 was in 23 and GCS 6-8 in 47; satisfactory recovery in 39 cases (55.7%), moderate disability in 12 (17.1%), severe deficit in 6 (8.6%), vegetative survival in 4 (5.7%) and 8 (11.4%) died. CONCLUSIONS: Tentoriun cerebelli incision is helpful in alleviating secondary brain stem injury from tentorial herniation and in reducing the disability and death rate of the patients.

Adolescent↗

PubMed2001

Early monitoring of P(ti)O(2), P(ti)CO(2), pH and brain temperature in patients with brain injuries and the clinical significance.

OBJECTIVE: To explore the regulation of early brain tissue metabolic changing after brain injuries and the clinical significance. METHODS: There were 17 patients with brain injuries. Early dire ct monitoring of P(ti)O(2), P(ti)CO(2), pH and brain temperature, dynamic observation of the relation between various parameters and clinics after brain injuries were performed. RESULTS: Early changes of P(ti)O(2), P(ti)CO(2) and pH were closely correlated with outcome. The death rate obviously increased when P(ti)O(2) was continuously lower than 9 mmHg within 24 hours after injuries. Secondary brain injury prolonged and aggravated brain tissue metabolic disturbance. When intracerebral pressure was over 30 mmHg P(ti)O(2) began to decrease. The brain temperature in brain death patients was evidently lower than axillary temperature. CONCLUSIONS: The direct monitoring of P(ti)O(2), P(ti)CO(2), pH and brain temperature is safe and accurate and can find early anoxia da mage to brain tissue and provide reliable basis for clinical therapy. It ha s an instructive significance in selecting and studying a new treatment method in brain injuries. And it can be taken as a criterion in clinical judging brain deaths.

Adult↗

PubMed2001

[Establishment of detective systems for GL-7ACA acylase expression].

Glutaryl-7-amino cephalosporanic acid (GL-7ACA) acylase catalyzes the conversion of GL-7ACA to 7-amino cephalosporanic acid (7-ACA). The product 7-ACA is a starting compound for semi-synthetic cephalosporin antibiotics in industry. In order to detect the expression and specific activity of protein-engineered GL-7ACA acylase accurately, two useful detective systems for its expression has been established, in which reporter genes xylE and lacZ were fused to the downstream the GL-7ACA acylase gene acy respectively and the activity of catechol dioxygenase or beta-galactosidase could indicate the amount of acy expression.

Catechol 2,3-Dioxygenase↗

PubMed2001

Studies on the development of DNA vaccine against Cysticercus cellulosae infection and its efficacy.

DNA vaccine against Cysticercus cellulosae infection was developed and its efficacy was tested. A pair of primers specific to antigen B gene of C. cellulosae was designed which amplified the gene successfully with RT-PCR. The gene was ligated to PV93 vector, and the recombinant of antigen B gene and PV93 was transformed to JM83 cells. The transformed JM83 cells were cultured in a large scale and the plasmid purified. Based on the recombinant plasmid. a DNA vaccine was developed and used to vaccinate two groups of experimental pigs. In each group, there was a routine vaccine, an enhanced vaccine and a control group. Groups 1 and 2 were challenged at 4 months and at 14 days post vaccination respectively with eggs of Taenia solium. The antibody response was also tested with ELISA. The results suggested that all animals vaccinated AgB gene DNA vaccine, no matter by routine or enhanced vaccine, their antibodies reached maximum peak 23 days post vaccination and decreased gradually. When the animals were challenged 4 months after vaccination, they had strong immunity and the parasites decrease rates were 91.2% and 93.1% respectively. When pigs vaccinated with AgB gene DNA vaccine were challenged 14 days post vaccination with 18,000 eggs/pig. The animals showed strong immunity and the parasite decrease rates were 99.5% and 84.9% respectively. However at that time, the antibodies did not reach the peak. While in the control group, the number of C. cellulosae was as many as 2,500. It was concluded that the pigs vaccinated with DNA vaccine had strong immunity against infection of eggs of T. solium.

Animals↗

PubMed2001

[Transfer and expression of tyrosinase gene of Pseudomonas maltophilia in Pseudomonas pseudoalcaligenes].

Pseudomonas pseudoalcaligenes is a notably killing maggots bacterium, which was isolated from natural dead maggots in the manure pits in the countryside of Yancheng. It easily die from effect of ultra-violet ray when it is exposed in the sun. Antiradiation effect of melanin is quite strong. Mel gene of P. maltophilia AT18 has been introduced into P. pseudoalcaligenes, and enabled it the ability of producing melanin steadily. Southern hybridization studies confirmed that the small fragment cloned in the P. pseudoalcaligenes comes from P. maltophilia DNA. SDS-PAGE analysis also revealed that an additional protein of 18 kD, which was equal to the size of the putative tyrosinase according to mel fragment, was exressed in the P. pseudoalcaligenes recombinant carrying the mel gene, The results of assay show that antiradiation effect of recombinant is quites strong, the effect time of killing maggats is longer than the recipient, the recombinant can't infect animals and fowls.

DNA, Bacterial↗

PubMed2001

[Melanin properties studies of the recombinant of Pseudomonas pseudoalcaligenes containing tyrosinase gene].

Pseudomonas pseudoalcaligenes is a notably killing maggots bacterium, which was isolated from natural dead maggots. Tyrosinase gene of P. maltophilia AT18 has been introduced into P. pseudoalcaligenes, and enabled it the ability of producing melanin steadily. Antiradiation effect of the melanin is quite strong. The melanin of the recombinant is nonfixiform material. It's solubility is very little in many sorts of organic or inorganic solvent. It's solubility is big in alkaline solution, but little in neutral or weak acid solution. It is deposited when pH < 4. It is oxidized by H2O2 or NaC10. It is also reduced by Ag+ or H2S. It has free radical and it can absorbs free radical generated by ultra-violent ray. It can absorbs ray of all sorts of wave length. The absorption rate of ultra-violet ray is the biggest in all sorts of wave length. It can effectively protects protein, DNA and other biomacromolecule matter against the damages by ultra-violet ray.

Free Radical Scavengers↗

PubMed2001

[Experimental study for repair of cranial defects with bone marrow stromal cells and modified alginate].

OBJECTIVE: The primary aim of this investigation was to determine whether expanded BMSCs in vitro mixed with modified alginate gelatin could repair critical defects in rats without the addition of exogenous growth or bone morphogenetic factors. METHODS: Bone marrow stem cells from syngeneic rats cultured in vitro and mixed with modified alginate gel to paint the cranial critical size defect. A full-thickness cranial plate defect was created without damage of dura mater. Modified alginate gelatin with or without BMSCs were painted over the cranial defects. Animals being made cranial defect but received no implant served as sham-operated controls. Craniotomy defects were divided into three groups, which included defects left unpainted (group I, n=6), defects painted with modified alginate gelatin alone (group II, n=6), and defects painted with a modified alginate mixed with BMSCs (group III, n=6). A total of 18 implant experiments were carried out, with postsurgical radiographic and histological analysis completed at 12 week. RESULTS: None of the implants exhibited extrusion or infection. Radiographs showed a likely increased calcification in group III, without finally new calcification in group I and in group II. Histology showed that group I and group II were featured by thinning of the bone at the edges of the defect margins with minimal bone growth inward and dense fibrous tissue with rudimentary alginate material spanning the intervenient gap. The results demonstrated that a great amount of new bone in growth took place in BMSCs-alginate group, stemming from cranial defect edges and proceeding inward. CONCLUSION: Transplantation of syngeneic BMSCs with alginate gel can serve as an example of a cell-based treatment for skeletal reformation and would be especially useful for augmenting or regenerating bone in skeletal defects. So syngeneic BMSCs with alginate gel demonstrate a potential technique to regenerate a variety of skeletal defects that occur in different clinical scenaries.

English Abstract↗

PubMed2000

Expression of semaphorins in developing and regenerating olfactory epithelium.

Semaphorins provide signals that guide growing axons to their appropriate destinations. The secreted semaphorin, Sema3A, mediates repulsive effects on axons from various neuronal populations in embryonic rats. The authors localized Sema3A mRNA expression in the primary olfactory pathway during development, in adult rats, and in adult rats that were subjected to a unilateral olfactory bulbectomy. Developing rats at ages from embryonic day 14 (E14) to E19 expressed Sema3A in the olfactory receptor neurons (ORNs) of the olfactory epithelium and in chondrogenic structures surrounding the nasal cavity. In vitro, ORN axons at E14 avoided substrate-bound Sema3A. Low levels of Sema3A expression persisted in the normal adult epithelium both in ORNs scattered throughout the epithelium and in small clusters. Three days after a unilateral olfactory bulbectomy, Sema3A transcript levels increased in regenerating neurons. High levels of Sema3A transcript were found at 1 week postbulbectomy, persisted for 2 weeks, and diminished by 3 weeks. Several other murine semaphorins (Sema4A, Sema4B, and Sema4C) were expressed differentially in the primary olfactory pathway both during development and regeneration. These findings suggest that Sema3A and perhaps other semaphorins play a role in directing ORNs out of the epithelium and to the olfactory bulb, their target structure, during both development and regeneration.

Age Factors↗

PubMed2000

Absence of proximal duct apoptosis in the ventral prostate of transgenic mice carrying the C3(1)-TGF-beta type II dominant negative receptor.

BACKGROUND: Prostatic epithelial cells are sensitive to the inhibitory effects of TGF-beta. However, TGF-beta signaling in the prostate is dependent on androgenic status. Under the in vivo conditions, it is difficult to dissociate the effect of TGF-beta from that of androgen on the prostate. METHODS: The objective of the present study was to create and verify a transgenic mouse system in which epithelial cells of the ventral prostate are insensitive to the actions of TGF-beta. By using a modified prostate-specific promoter, C3(1), the TGF-beta dominant negative receptor is only expressed in the epithelial cells of the ventral prostate, and these cells are resistant to TGF-beta. Morphology of transgenic animal prostates was compared to wild-type animal prostates by immunohistochemistry and microscopy. RESULTS: The prostate of transgenic mice exhibited an abnormal morphology with multiple layers of epithelial cells lining the proximal ducts, in contrast to the simple cuboidal monolayer of cells seen in the normal prostate. This observation was accompanied by a loss of apoptosis in this region, as seen by TUNEL assay. There was no significant difference in serum levels of testosterone between the wild-type and transgenic animals. CONCLUSIONS: These results demonstrated that a loss of sensitivity to TGF-beta results in the accumulation of multiple layers of epithelial cells in the proximal region of the ventral prostate. This abnormal growth illustrates that TGF-beta plays an important role in regulating prostate growth. The current transgenic system can be used as an experimental model to study the functional role of TGF-beta in prostatic growth and function.

Activin Receptors, Type I↗