Biomedical subjects

Y Yao

Publications and source records attributed to Y Yao.

At least 145 records · Page 8Linked to original sources

PubMed1998

Direct formation of human interleukin-11 by cis-acting system of plant virus protease in Escherichia coli.

To produce a large amount of recombinant proteins in Escherichia coli, we constructed a unique cis-acting expression system using a plant virus protease. This new expression system could directly produce recombinant proteins, that had a biologically active form. A gene of nuclear inclusion-a (NIa), which had a specific amino acid sequence, was fused with a foreign protein gene at the same protein reading frame. One of the NIa-specific cleavage amino acid sequences, Gln-Ala, was also contained at the protein-protein junction. In the case of human interleukin-11 (hIL-11), a 23-kDa specific signal band was obtained from recombinant bacteria. N-terminal sequencing of the 23-kDa protein showed that NIa specifically cleaved the fusion protein at Gln-Ala, producing Ala-hIL-11. Furthermore, we could produce the mature rhIL-11 by extending the culture time. This 23-kDa protein had the same biological activity as hIL-11 in a mouse plasmacytoma, T1165. Combined with fermentation control, we produced mature rhIL-11 in E. coli.

DNA Primers↗

PubMed1998

Identification and case management in an HMO of patients at risk of preterm labor.

We carried out a study of pregnant patients in a health maintenance organization to identify and provide case management of women at risk of preterm labor and to determine important risk factors for preterm labor in a managed care population. Data were collected on 794 women who completed an initial prenatal care visit at HealthAmerica of Pittsburgh between July 15, 1994, and March 31, 1995, and delivered at a local Pittsburgh hospital. The patients were assessed during an initial call to schedule their first prenatal visit and also at the 8- to 15-week and 24- to 28-week prenatal visits. Patients scoring 10 or higher on the risk assessment form were referred to a nurse case manager who provided education and support. Results of a logistic regression analysis suggest that the risk assessment tool was effective in identifying women at risk for preterm labor. "Physical/stressful work", as assessed by the patient, history of a prior preterm birth, and multiple gestation were all statistically significant predictors of preterm birth. Further research is needed to confirm the finding that physical or stressful work is a significant predictor of preterm births and to determine which aspects of the work may increase the patient's risk. This study was based on 8 months of data; however, additional program implementation is needed to evaluate fully the potential long-term benefits of the program.

Case Management↗

PubMed1998

N-ras mutations in 43 Chinese cases of acute myeloid leukemia.

OBJECTIVE: To detect 3 kinds of N-ras mutations in Chinese patients with acute myeloid leukemia (AML). METHODS: In vitro DNA amplification followed by oligonucleotide dot analysis were used to study N-ras gene mutations in 43 cases of acute myeloid leukemia (AML). 25 healthy people were used as controls. Patients were selected in the Beijing district and consisted of 19 males and 24 females. The average age was 37. The controls were healthy individuals with the average age of 36.5 from the same region. 3 oligonucleotide probes were artificially synthesized to detect mutations in codon 12 and 13 of N-ras. RESULTS: Five out of 43 AML samples have been found contain G-->A mutation in codon 12.2 have G-->T mutation in codon 12. One has G-->A mutation in codon 13. The mutation rate was 18.6%. None of the controls presented these mutations. The frequency of mutation of N-ras in the AML samples showed statistical differences with that of the controls. CONCLUSION: Analysis of the results suggests the N-ras mutations may have some relationship with the etiology of acute myeloid leukemia.

Adult↗

PubMed1998

[Relationship between plasma D(-)-lactate levels and acute intestinal injury in rats following ischemia-reperfusion].

OBJECTIVE: To determine the kinetics of plasma D(-)-lactate levels in both portal and systemic circulations, and to examine whether elevated plasma D(-)-lactate would correlate to intestinal injury in rats subjected to acute intestinal ischemia-reperfusion. METHODS: Anesthetized rats underwent 75 minutes of superior mesenteric artery occlusion followed by 6 hours of reperfusion. Plasma D(-)-lactate levels were measured by an enzymatic spectrophotometric assay. RESULTS: It showed that intestinal ischemia for 75 minutes resulted in a significant elevation in D(-)-lactate levels in portal vein blood compared to baseline values (P < 0.05). Plasma D(-)-lactate levels had a tendency to further increase after reperfusion up to 6 hours. Similar alterations in D(-)-lactate were also found in systemic circulation, there were no significant differences between the portal and systemic circulation at any time point. Moreover, the histopathological evaluation scores were significantly correlated to the portal D(-)-lactate levels in animals at various time points (r = 0.415, P < 0.01). In addition, a remarkable rise of endotoxin concentration within portal vein was already found at the end of 75-minute ischemia (P < 0.05), reaching a peak at 2 hours post-reperfusion. CONCLUSION: These data suggest that acute intestinal ischemia is associated with failure of mucosal barrier resulting in increased plasma D(-)-lactate levels in both portal and systemic blood. The subsequent reperfusion might cause further increase in D(-)-lactate levels, which correlated to the histopathological alterations. Plasma D(-)-lactate may be a useful marker of intestinal injury following both ischemia and reperfusion insults.

Animals↗

PubMed1998

[Changes of cerebral blood flow during hypoxicischemic encephalopathy in newborn pigs].

This study was designed to explore the change of cerebral blood flow during hypoxic-ischemic encephalopathy (HIE). Sixteen newborn pigs were devided into four groups: the normal control, 15 minutes after HIE, 30 minutes after HIE and 60 minutes after HIE. The shapes of the cerebral blood vessels were obsessed by the prepared Chinese ink irrigation and the width and volume fraction of capillary were tested and analyzed by stereographic method respectively. The results showed the small blood vessels were interrupted with the passage of time. At the time of 60 minutes after HIE, capilaries almost disappeared from view, only a few ends of blood vessels in the sheap of a broken tree were seen. The width of capillaries and small veins became more and more narrow as time went on. The percentages of capillary volume fraction and small vein volume fraction became smaller and smaller (P < 0.05). These demonstrate that the fall of cerebral blood flow plays an important role in the development of HIE.

Animals↗

PubMed1998

[Follicular fluid from patients with endometriosis decreases the binding of human sperm to zona pellucida in hemizona assay].

OBJECTIVE: To evaluate the effects of follicular fluid (FF) from women with endometriosis and tubal factor on sperm binding to zona pellucida under hemizona assay(HZA). METHODS: Follicular fluid was collected at IVF from patients with endometriosis and without endometriosis (tubal factor infertility). The HZA was used to study the effect of FF from patients with endometriosis and tubal factor on sperm binding to zona pellucida using media (EBSS/BSA) as control. RESULTS: The mean number of sperm binding to zona in endometriosis specimens and tubal factor infertility was significantly fewer than the number treated by culture medium (91 +/- 21 vs 239 +/- 35, P < 0.001; 109 +/- 22 vs 211 +/- 42, P < 0.005). The hemizona index was lower when the incubation was performed with FF from endometriosis patients compared with sperm incubated in FF from tubal factor patients (36 +/- 4 vs 54 +/- 4, P < 0.005). CONCLUSIONS: The inhibiting effect of FF from endometriosis patients is stronger than those without endometriosis. The follicular fluid of patients with endometriosis could contribute to infertility through impairment of gamete interaction.

Adult↗

PubMed1998

[A model of nasopharyngeal carcinoma with spontaneous highly lymphatic metastasis in nude mice and its biological characteristics].

OBJECTIVES: To establish a model of nasopharyngeal carcinoma with spontaneous highly lymphatic metastasis in nude mice and to study its biological characteristics. METHODS: The clone cells of nasopharyngeal carcinoma(NPC), CNE-2Z-H5, were inoculated into nude mice. The cancer cells of lymph node metastatic foci were transplanted into nude mice again when the metastasis of nude mice were observed. After repetition of this procedure for 9 cycles, the metastatic rate and the metastatic paths were observed in nude mice of every passage; The changes were also observed in proliferation ability, expression of growth factor and its receptor in vitro, proliferation index(PI), and tumor weight and doubling time of the transplantable tumor in every passage in vivo. RESULTS: The lymphatic metastatic rates were higher than 85%. The metastatic paths were single, the proliferation ability was increased in cancer cells of every passage in vivo and vitro after passaging cancer cells of lymphatic metastatic foci for 9 cycles in nude mice. CONCLUSIONS: A model of nasopharyngeal carcinoma with spontaneous highly lymphatic metastasis has been established in nude mice, and the possibilities of metastasis and proliferation are increased after progression of NPC cells in nude mice. There is a close relationship between the metastasis and proliferation in NPC.

Animals↗

PubMed1998

Reevaluation of effect of albendazole on echinococcus multilocularis infection in mice and gerbils.

OBJECTIVE: To study the effect for albendazole therapy for alveolar echinococcus infection in gerbils and mice. METHODS: Mice and gerbils were infected of metacestode tissues by intraperitoneal (i.p.) transplantation and treated with albendazole-medicated feeds. The effects were evaluated by comparison of the treated and control groups in terms of host mortality, larval metastases to lungs and liver, final larval weight, histopathological, and ultrastructural examination of metacestode tissues. Viability of metacestode tissues at necropsy of treated animals was tested by intraperitoneal transplantation into uninfected animals. RESULTS: Albendazole-medicated feeds significantly inhibited larval growth of Echinococcus multilocularis (E. multilocularis) both in mice and gerbils with markedly reduced host mortality and pulmonary and liver metastases. Viability test showed that albendazole therapy was parasiticidal in early stage of experimental infection. Light microscopic and ultrastructural examination of metacestode tissues of the treated animals revealed severe destruction and massive necrosis with marked calcification of protoscoleces and residual tissues. CONCLUSION: Continuous long term albendazole therapy in animal models is parasiticidal against larval E. multilocularis especially in early stage of infection.

Albendazole↗

PubMed1998

The role of gut as a cytokine-generating organ in remote organ dysfunction after intestinal ischemia and reperfusion.

OBJECTIVE: To test the hypothesis that in a rat model of acute intestinal ischemia/reperfusion injury, endotoxemia from the gastrointestinal tract would play a role in mediating tumor necrosis factor (TNF) response and remote organ dysfunction. METHODS: Wistar rats underwent 45 minutes of superior mesenteric artery occlusion followed by 6 hours of reperfusion. The rats were treated intravenously with either TNF monoclonal antibody (MoAb) or saline solution 90 minutes prior to the onset of ischemia. RESULTS: Significant elevation of plasma TNF level in both portal and systemic circulation was detected immediately after the onset of reperfusion. The level peaked at two hours after reperfusion (P < 0.01). Similarly, a remarkable TNF mRNA expression in the intestine in controls was detected at 0.5 hour post-reperfusion, and sustained a marked elevation throughout the observation period (P < 0.05-0.01). TNF elevation was found associated with gut-origin endotoxemia, and the maximal TNF response occurred approximately 0.5-2 hours after the initial appearance of endotoxin in the portal vein. Concomitantly, multiple organ dysfunction in response to local ischemic insult was also observed in untreated controls upon reperfusion, but it was significantly attenuated by pretreatment with MoAb against TNF. CONCLUSIONS: Intestinal injury can result in the gut becoming a cytokine-liberating organ. The escape of endotoxin and bacteria from the gut may be responsible for the TNF expression and release, which would be an important mechanism underlying pathophysiological alterations associated with intestinal ischemia/reperfusion injury.

Animals↗

PubMed1998

[Comparative study on results of pulmonary tuberculosis surveillance before and during implementation of tuberculosis control project in Ningxia Hui autonomous region].

OBJECTIVE: To understand the effect of the World Bank-loaned tuberculosis control project in Ningxia Hui autonomous region. METHOD: Five counties which can reflect the situation of tuberculosis control in Ningxia were selected for observation, and the same method of surveillance was carried out. The subjects investigated were required to fill in the surveillance and the project forms at the same time, and the data of the tuberculosis control before (1990, 1991) and during (1995, 1996) implementation of the project were compared. RESULT: The registration rate of new smear-positive patients was 20.35 per 100,000 population during the implementation of the project, with a 3.06 times increase compared with that before implementation of the project. The proportion of new smear-positive patients increased from 21.37% to 61.70%, the smear-positive rate of newly registered patients from 22.80% to 35.32%, and the finding rate of new smear-positive patients from 7.97% to 31.11%. The mortality rate of pulmonary tuberculosis decreased by 58.36%. The total impact of finding and treatment increased from 7.60% to 31.90%. CONCLUSION: Satisfactory results have been achieved during the implementation of the project in Ningxia.

China↗

PubMed1998

[Effects of whole-body vibration on human tracking performance and visual-motor reaction].

Dual task test (light target tracking and visual-motor reaction of visual oddball mode) and pursuit aiming test were done in 17 male healthy subjects after 30min exposure to whole-body vibrations of 20 Hz 0.15 gz or 20 Hz 0.3 gz. Mean accuracy rate of visual-motor reaction and target stimulus reaction accuracy rate after 0.3 gz vibration were significantly lower than those of control group (P < 0.05), while after 0.15 gz vibration, the changes were not significant. Comparing with control group, the total number of right and wrong pointing, pointing speed in pursuit aiming test were significantly lower (P < 0.05) after vibration. However, light target tracking error, mean reaction time of visual-motor reaction and pointing accuracy rate of pursuit aiming test had no significant change after exposure to any kind of the vibrations. It may be concluded that some kinds of effect on human tracking performance and visual-motor reaction were observed after exposure to whole-body vibration.

Adult↗

PubMed1998

[Effect of repeated cerebral ischemia induced by lower body negative pressure on neuronal morphology and ions contents, ATPase activity of brain tissue in rats].

To investigate the effect of repeated + Gz-induced loss of consciousness on the brain and its mechanism, we observed the changes of ions contents, ATPase activity of brain tissues and neuronal morphology after repeated cerebral ischemia induced by lower body negative pressure(LBNP) in rats. Thirty male Sprague-Dawley rats were divided into 3 groups randomly. Rats were anesthetized and exposed to LBNP of -4 kPa at a rate of 0.67 kPa/s. The pressure rapidly returned to control level 2 min after EEG becomes isoelectric. Cortical Na(+)-K(+)-ATPase activity decreased significantly lh after one LBNP exposure (P < 0.05), While Na+, K+ and water contents of brain tissues showed a tendency to increase (P > 0.05). Na(+)-K(+)-ATPase activity decreased significantly while Na+, K+ and water contents increased significantly 1 h after three LBNP exposures, and ischemic changes were found in a few neurons. It suggested that three cerebral ischemia exposure induced by LBNP can result in disturbance of ion homeostasis and neuronal damage.

Animals↗

PubMed1998

[Effect of TNF-alpha monoclonal antibody on tissue lipopolysaccharide-binding protein mRNA expression in rats after thermal injury].

OBJECTIVE: To explore the effects of tumor necrosis factor-alpha (TNF-alpha) monoclonal antibody (MAb) on tissue TNF-alpha and lipopolysaccharide-binding protein (LBP) mRNA expression, and multiple organ dysfunction in rats after thermal injury. METHOD: 24 male Wistar rats were subjected to a 35% total body surface area full-thickness thermal injury. RESULT: The tissue TNF-alpha and LBP mRNA expressions of liver, lung, intestine, and kidney were markedly increased (P < 0.05 approximately equal 0.01) after thermal injury. Treatment with TNF-alpha MAb could significantly lower TNF-alpha mRNA expression of lung, intestine and kidney, but had no effect on liver TNF-alpha mRNA expression (P > 0.05). Similarly, the tissue LBP mRNA expression also decreased significantly (36.0% - 72.9%), and returned to normal in lung, intestine and kidney. In addition, biochemical parameters including GPT, TBiL, BUN, CK-MB, and LDH were markedly elevated after thermal injury, and decreased significantly after treatment with TNF-alpha MAb. CONCLUSION: The increase of tissue TNF-alpha gene expression caused by thermal injury might be associated with a marked elevation of tissue LBP mRNA expression, which could contribute to the development of multiple organ dysfunction. The early use of TNF-alpha MAb seems to be effective in inhibiting significant LBP mRNA expression in various tissues and ameliorating multiple organ damage after major thermal injury.

Acute-Phase Proteins↗

PubMed1998

[The significance of changes in serum soluble lipopolysaccharide receptor CD14 levels in burned patients with multiple organ dysfunction syndrome].

OBJECTIVE: To determine whether an increased soluble lipopolysaccharide receptor CD14 (sCD14) level is associated with the development of multiple organ dysfunction syndrome (MODS) in patients after major burns. METHOD: 22 patients with burns covering more than 70% of body surface area were studied. These patients were divided into two groups according to the occurrence of MODS (MODS group, n = 9; non-MODS group, n = 13). Blood samples were obtained from burned patients. Serum concentrations of sCD14 and tumor necrosis factor (TNF) were determined by sandwich ELISA. Plasma endotoxin was measured using a quantitative chromogenic LAL test. RESULT: Compared to the healthy volunteers, a significant increase in serum sCD14 levels was observed in 22 patients on day 7 postburn, which remained marked elevation up to 21 days after thermal insult (P < 0.01). The serum sCD14 levels of the MODS group were significantly higher than those of the non-MODS group on days 7, 14, and 21 postburn (P < 0.05). Additionally, the serum sCD14 and endotoxin levels were positively correlated in patients who developed MODs on days 7, 14 and 21 postburn (P < 0.05), whereas no correlation was found between sCD14 and TNF levels at any time point (P > 0.05). CONCLUSION: Our data suggest that sCD14 elevation is associated with the development of MODS after major burns, and endotoxin release may be involved in the activation of sCD14 under certain pathophysiological conditions.

Adolescent↗

PubMed1998

[Study on tissue culture of Poligonum multiflorum].

In the present thesis, suitable medium for callus inducement and relationship between culture time and callus growth of Poligonum multiflorum were studied by mono-factorial and orthogonal design test. The experiments showed that the best medium for callus inducement was MS + 2,4-D 1 mg/L + 6-BA 1 mg/L + IBA 0.5 mg/L, dark culture was better than light culture, callus grew fast when it was cultured 12 days, whole plant could be induced by callus, the induce rate was 95%.

Culture Media↗

PubMed1998

[Pharmacological studies of shundao granules on gastrointestinal track].

The traditional Chinese medicine Shundao Granules po markedly inhibited the formation of gastric ulcers induced by indomethacin, restraint and pyloric ligatin in rats. A decreased volume of gastric juice collected from pyloric ligated stomaches and a reduced level of gastric acid have been observed. The results showed that Shundao Granules had markedly analgesic action and significantly enhanced intestinal movement in mice, increased propulsive rate of small ingestion in mice.

Analgesics↗

PubMed1997

Topology of T cell receptor-peptide/class I MHC interaction defined by charge reversal complementation and functional analysis.

The molecular interactions between the CD8 co-receptor dependent N15 and N26 T cell receptors (TCRs) and their common ligand, the vesicular stomatitis virus octapeptide (VSV8) bound to H-2Kb, were studied to define the docking orientation(s) of MHC class I restricted TCRs during immune recognition. Guided by the molecular surfaces of the crystallographically defined peptide/MHC and modeled TCRs, a series of mutations in exposed residues likely contacting the TCR ligand were analyzed for their ability to alter peptide-triggered IL-2 production in T cell transfectants. Critical residues which diminished antigen recognition by 1000 to 10,000-fold in molar terms were identified in both N15 Valpha (alphaE94A or alphaE94R, Y98A and K99) and Vbeta (betaR96A, betaW97A and betaD99A) CDR3 loops. Mutational analysis indicated that the Rp1 residue of VSV8 is critical for antigen recognition of N15 TCR, but R62 of H-2Kb is less critical. More importantly, the alphaE94R mutant could be fully complemented by a reciprocal charge reversal at Kb R62 (R62E). This result suggests a direct interaction between N15 TCR Valpha E94R and Kb R62E residues. As Rp1 of VSV8 is adjacent to R62 in the VSV8/Kb complex and essential for T cell activation, this orientation implies that the N15 Valpha CDR3 loop interacts with the N-terminal residues of VSV8 with the Valpha domain docking to the Kb alpha2 helix while the N15 Vbeta CDR3 loop interacts with the more C-terminal peptide residues and the Vbeta domain overlies the Kb alpha1 helix. An equivalent orientation is suggested for N26, a second VSV8/Kb specific TCR. Given that genetic analysis of two different class II MHC-restricted TCRs and two crystallographic studies of class I restricted TCRs offers a similar overall orientation of V domains relative to alpha-helices, these data raise the possibility of a common docking mode between TCRs and their ligands regardless of MHC restriction.

Amino Acid Sequence↗

PubMed1997

Expression of interleukin-1beta in human breast carcinoma.

BACKGROUND: Interleukin 1beta (IL-1beta) is a multifunctional cytokine that up-regulates the inflammatory response. It is not known whether IL-1beta plays a major role in human malignancy. To determine whether IL-1beta might be involved in breast carcinoma progression, the authors measured the IL-1beta content in tissue extracts from >200 invasive breast carcinomas and smaller numbers of ductal carcinoma in situ (DCIS) and benign lesions. METHODS: IL-1beta content was measured by an enzyme-linked immunoadsorbent assay and analyzed to determine whether these values were correlated with the contents of scatter factor (SF) (an invasogenic and angiogenic cytokine), von Willebrand's factor (VWF) (a marker of endothelium), thrombospondin-1 (TSP1) (an antiadhesive and antiangiogenic glycoprotein), and tumor necrosis factor-alpha (TNF alpha) (another proinflammatory cytokine). Studies were also performed to determine whether IL-1beta content was correlated with other pathologic and immunochemical variables that have been utilized or proposed as prognostic indicators for breast carcinoma. RESULTS: The most important findings of these studies were: 1) immunoreactive IL-1beta was detected in approximately 90% of invasive breast carcinomas; 2) IL-1beta levels were significantly higher in invasive carcinomas than in a group of DCIS and benign lesions; 3) high IL-1beta content in invasive carcinomas was significantly associated with higher contents of SF, VWF, and TSP1, but not TNF alpha; and 4) there was a trend toward higher IL-1beta content in invasive carcinomas with a group of other parameters that suggest a biologically more aggressive tumor (estrogen receptor negativity, high tumor grade, p53 positivity, and bcl-2 negativity); and the proportion of invasive tumors with these characteristics was significantly increased in a subgroup of tumors having very high IL-1beta content. The authors also found a correlation between high IL-1beta content and CD68 positivity, suggesting that macrophages may account for some of the IL-1beta present in human breast carcinoma tissue. CONCLUSIONS: These findings suggest that significant titers of IL-1beta are present within the microenvironment of most breast carcinomas and that a high IL-1beta content is often associated with tumor invasiveness and with other pathologic features suggestive of an aggressive tumor biology.

Biomarkers↗