Biomedical subjects

Y Xiao

Publications and source records attributed to Y Xiao.

At least 73 records · Page 4Linked to original sources

PubMed2001

Growth-hormone-stimulated dentinogenesis in Lewis dwarf rat molars.

In dentinogenesis, certain growth factors, matrix proteoglycans, and proteins are directly or indirectly dependent on growth hormone. The hypothesis that growth hormone up-regulates the expression of enzymes, sialoproteins, and other extracellular matrix proteins implicated in the formation and mineralization of tooth and bone matrices was tested by the treatment of Lewis dwarf rats with growth hormone over 5 days. The molar teeth were processed for immunohistochemical demonstration of bone-alkaline phosphatase, bone morphogenetic proteins-2 and -4, osteocalcin, osteopontin, bone sialoprotein, and E11 protein. Odontoblasts responded to growth hormone by more cells expressing bone morphogenetic protein, alkaline phosphatase, osteocalcin, and osteopontin. No changes were found in bone sialoprotein or E11 protein expression. Thus, growth hormone may stimulate odontoblasts to express several growth factors and matrix proteins associated with dentin matrix biosynthesis in mature rat molars.

Alkaline Phosphatase↗

PubMed2001

Effect of polyunsaturated fatty acid (PUFA) supplementation on intestinal inflammation and necrotizing enterocolitis (NEC) in a neonatal rat model.

Inasmuch as long-chain polyunsaturated fatty acids (PUFA, metabolites of the essential n-3 and n-6 fatty acids) are known to modulate inflammation, we hypothesized that supplementation of formula with these compounds would prevent necrotizing enterocolitis (NEC) and intestinal inflammation in our neonatal rat model. Newborn rats were stressed with asphyxia and formula feeding, and randomly assigned to control formula, control with PUFA supplementation, and PUFA with nucleotides. Animals were followed for 72--96 h and assessed for death, gross and histologic NEC, intestinal apoptosis, endotoxemia, and intestinal mRNA synthesis of phospholipase A(2)-II (rate-limiting enzyme for platelet activating factor production), platelet activating factor receptor, and inducible nitric oxide synthase. We found that PUFA reduced the incidence of death and NEC compared with the other groups (NEC 8 of 24 versus 17 of 24 control and 13 of 23 PUFA + nucleotides, p < 0.05). Furthermore, PUFA reduced plasma endotoxemia at 48 h (25 +/- 4 EU/mL versus 276 +/- 39 EU/mL in control and 170 +/- 28 EU/mL in PUFA + nucleotide), intestinal phospholipase A(2)-II expression at 24 h, and platelet activating factor receptor expression at 48 h. Formula supplementation had no effect on apoptosis of intestinal epithelium or intestinal inducible nitric oxide synthase expression. Addition of nucleotides with PUFA abrogated the beneficial effects of PUFA on intestinal inflammation. We conclude that PUFA reduces the incidence of NEC and intestinal inflammation in a neonatal rat model.

Animals↗

PubMed2001

Growth hormone induces bone morphogenetic proteins and bone-related proteins in the developing rat periodontium.

The hypothesis that growth hormone (GH) up-regulates the expression of enzymes, matrix proteins, and differentiation markers involved in mineralization of tooth and bone matrices was tested by the treatment of Lewis dwarf rats with GH over 5 days. The molar teeth and associated alveolar bone were processed for immunohistochemical demonstration of bone morphogenetic proteins 2 and 4 (BMP-2 and -4), bone morphogenetic protein type IA receptor (BMPR-IA), bone alkaline phosphatase (ALP), osteocalcin (OC), osteopontin (OPN), bone sialoprotein (BSP), and E11 protein (E11). The cementoblasts, osteoblasts, and periodontal ligament (PDL) cells responded to GH by expressing BMP-2 and -4, BMPR-IA, ALP, OC, and OPN and increasing the numbers of these cells. No changes were found in patterns of expression of the late differentiation markers BSP and E11 in response to GH. Thus, GH evokes expression of bone markers of early differentiation in cementoblasts, PDL cells, and osteoblasts of the periodontium. We propose that the induction of BMP-2 and -4 and their receptor by GH compliments the role of GH-induced insulin-like growth factor 1 (IGF-1) in promoting bone and tooth root formation.

Alkaline Phosphatase↗

PubMed2001

The expression of plasminogen activator system in a rat model of periodontal wound healing.

BACKGROUND: The plasminogen activator system has been proposed to play a role in proteolytic degradation of extracellular matrices in tissue remodeling, including wound healing. The aim of this study was to elucidate the presence of components of the plasminogen activator system during different stages of periodontal wound healing. METHODS: Periodontal wounds were created around the molars of adult rats and healing was followed for 28 days. Immunohistochemical analyses of the healing tissues and an analysis of the periodontal wound healing fluid by ELISA were carried out for the detection of tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), and 2 plasminogen activator inhibitors (PAI-1 and PAI-2). RESULTS: During the early stages (days 1 to 3) of periodontal wound healing, PAI-1 and PAI-2 were found to be closely associated with the deposition of a fibrin clot in the gingival sulcus. These components were strongly associated with the infiltrating inflammatory cells around the fibrin clot. During days 3 to 7, u-PA, PAI-1, and PAI-2 were associated with cells (particularly monocytes/macrophages, fibroblasts, and endothelial cells) in the newly formed granulation tissue. During days 7 to 14, a new attachment apparatus was formed during which PAI-1, PAI-2, and u-PA were localized in both periodontal ligament fibroblasts (PDL) and epithelial cells at sites where these cells were attaching to the root surface. In the periodontal wound healing fluid, the concentration for t-PA increased and peaked during the first week. PAI-2 had a similar expression to t-PA, but at a lower level over the entire wound-healing period. CONCLUSIONS: These findings indicate that the plasminogen activator system is involved in the entire process of periodontal wound healing, in particular with the formation of fibrin matrix on the root surface and its replacement by granulation tissue, as well as the subsequent formation of the attachment of soft tissue to the root surface during the later stages of wound repair.

Animals↗

PubMed2001

Effect of ischemia-reperfusion on the renal brush-border membrane sodium-dependent phosphate cotransporter NaPi-2.

To understand the mechanisms underlying ischemia-reperfusion-induced renal proximal tubule damage, we analyzed the expression of the Na+-dependent phosphate (Na+/Pi) cotransporter NaPi-2 in brush border membranes (BBM) isolated from rats which had been subjected to 30 min renal ischemia and 60 min reperfusion. Na+/Pi cotransport activities of the BBM vesicles were also determined. Ischemia caused a significant decrease (about 40%, P < 0.05) in all forms of NaPi-2 in the BBM, despite a significant increase (31+/-3%, P < 0.05) in the Na+/Pi cotransport activity. After reperfusion, both NaPi-2 expression and Na+/Pi cotransport activity returned to control levels. In contrast with Na+/Pi cotransport, ischemia significantly decreased Na+-dependent glucose cotransport but did not affect Na+-dependent proline cotransport. Reperfusion caused further decreases in both Na+/glucose (by 60%) and Na+/proline (by 33%) cotransport. Levels of NaPi-2 were more reduced in the BBM than in cortex homogenates, suggesting a relocalization of NaPi-2 as a result of ischemia. After reperfusion, NaPi-2 levels returned to control values in both BBM and homogenates. These data indicate that the NaPi-2 protein and BBM Na+/Pi cotransport activity respond uniquely to reversible renal ischemia and reperfusion, and thus may play an important role in maintaining and restoring the structure and function of the proximal tubule.

Animals↗

PubMed2001

Cocaine-mediated apoptosis in bovine coronary artery endothelial cells: role of nitric oxide.

The present study examined the role of nitric oxide in cocaine-induced apoptosis in bovine coronary artery endothelial cells (BCAECs). Cocaine produced a time-dependent decrease in cell viability and an increase in apoptosis in BCAECs, which were blocked by the nitric oxide donors DETA-NONOate (DETA-NO) and S-nitroso-N-acetyl-penicillamine. In accordance, cocaine decreased nitric oxide production in BCAECs at each time point of the study. Cocaine significantly increased caspase-3 activity that was blocked by the inhibitors of cytochrome c release (cyclosporin A), caspase-3 (Ac-DEVD-CHO), and caspase-9 (Z-LEHD-FMK), respectively. In addition, cocaine activated caspase-9, which was blocked by cyclosporin A and Z-LEHD-FMK. Ac-DEVD-CHO only partially blocked cocaine-induced caspase-9 activity. DETA-NO (20 microM) blocked cocaine-mediated activation of both caspase-9 and caspase-3. Cocaine decreased Bcl-2 protein levels, which was partially blocked by Ac-DEVD-CHO and Z-LEHD-FMK, but not by DETA-NO. Furthermore, cocaine induced a translocation of Bax from the cytosol to the mitochondria in BCAECs, and increased Bax levels in mitochondria by 2.2-fold. In accordance, cytosolic Bax levels decreased about 42%. Neither Ac-DEVD-CHO nor DETA-NO affected cocaine-induced translocation of Bax. We conclude that cocaine-induced Bcl-2 protein down-regulation and Bax translocation to the mitochondria are upstream signals of caspase-9 activation that precedes caspase-3. Cocaine-induced attenuation of nitric oxide plays a key role in the activation of the caspase cascade in BCAECs.

Animals↗

PubMed2001

Agonist regulation of rat alpha 3 beta 4 nicotinic acetylcholine receptors stably expressed in human embryonic kidney 293 cells.

Effects of agonists on rat alpha 3 beta 4 nicotinic acetylcholine receptors expressed in KX alpha 3 beta 4R2 cells [human embryonic kidney 293-derived cells] were studied. The potencies of seven agonists varied over a 7000-fold range, with a rank order of epibatidine >> A85380 > cytisine approximately 1,1-dimethyl-4-phenyl-piperazinium iodide (DMPP) approximately nicotine > acetylcholine > carbachol. The efficacies of all of the agonists studied here were similar except for DMPP, which seemed to be a partial agonist compared with nicotine and acetylcholine. Nicotine and carbachol desensitized the receptors in a time- and concentration-dependent manner. The EC(50) values for nicotine and carbachol to desensitize the receptors during a 60-min exposure were 3 and 51 microM, respectively, indicating that these agonists are more potent at desensitizing the receptors than at activating them. The function of the receptors recovered from agonist-induced desensitization rapidly and almost completely. The half-time for recovery of function from desensitization after a 60-min treatment with nicotine increased with the concentration of nicotine used to desensitize the receptors. In contrast, no such concentration dependence for time to recovery of function was found when carbachol was used to desensitize the receptors. We propose that this difference may be due to the cell permeability of nicotine, allowing it to enter and be sequestered inside of cells and then slowly diffuse out to maintain receptor desensitization. After a 5-day exposure to 100 microM nicotine, the receptors were completely desensitized, but receptor function recovered to 83% of control values with a half-time of about 10.5 min. Although the number of nicotinic receptor binding sites measured with (+/-)-[(3)H]epibatidine was increased during the chronic treatment with nicotine, no increase in function was detected.

Animals↗

PubMed2001

[Removal of NH4(+)-N from polluted water resources by bioremediation of biofilm process with elastic packing & micropore aerator].

The effect of NH4(+)-N removal in the polluted raw water of water sources by the bioremediation action of the biocontact oxidation process with the elastic packing and micropore aerator was studied in this paper. The research results showed the bioremediation process can reach a removal ratio of 64%-95% for NH4(+)-N of water sources under the condition of ordinary temperature 20 degrees C-27 degrees C, CODMn 7-14 mg/L, NH4(+)-N 0.7-2.0 mg/L in the water sources and the running parameters HRT 1.4 h, gas and water ratio 0.5:1, and DO 7-9 mg/L for the bioremediation process and a removal ratio of 40%-63% for NH4(+)-N of water sources under the condition of low temperature 7 degrees C-12 degrees C, CODMn 6-11 mg/L, NH4(+)-N 1.2-8.0 mg/L in the water sources and the running parameters HRT 1.4 h, gas and water ratio 0.5:1, and DO 8-10 mg/L for the bioremediation process.

Biofilms↗

PubMed2001

Blockade of rat alpha3beta4 nicotinic receptor function by methadone, its metabolites, and structural analogs.

The opioid agonist properties of (+/-)-methadone are ascribed almost entirely to the (-)-methadone enantiomer. To extend our knowledge of the pharmacological actions of methadone at ligand-gated ion channels, we investigated the effects of the two enantiomers of methadone and its metabolites R-(+)-2-ethyl-1,5-dimethyl-3,3-diphenylpyrrolinium perchlorate (EDDP) and R-(+)-2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline hydrochloride (EMDP), as well as structural analogs of methadone, including (-)-alpha-acetylmethadol hydrochloride (LAAM) and (+)-alpha-propoxyphene, on rat alpha3beta4 neuronal nicotinic acetylcholine receptors (nAChRs) stably expressed in a human embryonic kidney 293 cell line, designated KXalpha3beta4R2. (+/-)-methadone inhibited nicotine-stimulated 86Rb+ efflux from the cells in a concentration-dependent manner with an IC50 value of 1.9 +/- 0.2 microM, indicating that it is a potent nAChR antagonist. The (-)- and (+)-enantiomers of methadone have similar inhibitory potencies on nicotine-stimulated 86Rb+ efflux, with IC50 values of approximately 2 microM. EDDP, the major metabolite of methadone, is even more potent, with an IC50 value of approximately 0.5 microM, making it one of the most potent nicotinic receptor blockers reported. In the presence of (+/-)-methadone, EDDP, or LAAM, the maximum nicotine-stimulated 86Rb+ efflux was markedly decreased, but the EC50 value for nicotine stimulation was altered only slightly, if at all, indicating that these compounds block alpha3beta4 nicotinic receptor function by a noncompetitive mechanism. Consistent with a noncompetitive mechanism, (+/-)-methadone, its metabolites, and structural analogs have very low affinity for nicotinic receptor agonist binding sites in membrane homogenates from KXalpha3beta4R2 cells. We conclude that both enantiomers of methadone and its metabolites as well as LAAM and (+)-alpha-propoxyphene are potent noncompetitive antagonists of alpha3beta4 nAChRs.

Binding, Competitive↗

PubMed2001

[The impact of early diagnosis and thrombolytic-anticoagulant therapies on outcome of pulmonary embolism].

OBJECTIVE: To investigate the effect of early diagnosis and thrombolytic followed by anticoagulant therapy in pulmonary embolism (PE). METHODS: 46 patients diagnosed as PE were retrospectively analyzed. All the patients were treated with thrombolytic followed by anticoagulant therapy. Therapeutic effect was compared between two groups of patients with symptoms more or less than two weeks before establishment of diagnosis. RESULT: 36 patients were documented as PE by lung scan, 13 of 46 patients (28.3%) were misdiagnosed as other heart or lung diseases. All the patients had accompanying diseases, including leg deep vein thrombosis (DVT) (33/46, 71.7%) heart or lung diseases other than PE(23/46, 50%), and history of surgery (6/46, 3%). 93.1% of the patients with clinical history less than 2 weeks showed improvement, whereas only 52.9% of those with clinical history exceeding 2 weeks improved. There was significant difference between them. CONCLUSION: In order to diagnose PE early, we should pay more attention to the risk factors of PE, especially DVT. The success of thrombolysis appears to depend on the interval between the onset of symptoms and start of thrombolytic therapy. Patients with clinical symptoms less than 2 weeks show better improvement.

Adult↗

PubMed2001

[Influence of specimen processing method on Mycobacterium tuberculosis detection by PCR-reversed dot hybridization].

OBJECTIVE: To evaluate specimen processing with sodium dodecyl (lauryl) sulfate (SDS) on the detection of Mycobacterium tuberculosis by PCR-reversed dot hybridization. METHODS: Totally 266 specimens were collected from sputum, pleural fluid, ascites, urine or blood of patients with active tuberculosis and were treated with SDS or routine method. All specimens handled were tested for detecting M. tuberculosis by PCR-reversed dot hybridization. RESULTS: The detection rate of M. tuberculosis from specimens prepared by SDS method was 65.0% (173/266) as compared with 51.5% (136/168) by routine method. Results from two methods were considered statistically significant (chi(2) = 35.03, P < 0.001). CONCLUSION: The SDS processing method may be used to detect M. tuberculosis from clinical specimens by PCR and enhances the detection rate of M. tuberculosis.

Detergents↗

PubMed2001

Large public display boards: a case study of an OR board and design implications.

A compelling reason for studying artifacts in collaborative work is to inform design. We present a case study of a public display board (12 ft by 4 ft) in a Level-I trauma center operating room (OR) unit. The board has evolved into a sophisticated coordination tool for clinicians and supporting personnel. This paper draws on study findings about how the OR board is used and organizes the findings into three areas: (1) visual and physical properties of the board that are exploited for collaboration, (2) purposes the board was configured to serve, and (3) types of physical and perceptual interaction with the board. Findings and implications related to layout, size, flexibility, task management, problem-solving, resourcing, shared awareness, and communication are discussed in an effort to propose guidelines to facilitate the design of electronic, computer driven display boards in the OR environment.

Audiovisual Aids↗

PubMed2001

The operating room charge nurse: coordinator and communicator.

To achieve the potential inherent in the use of computer applications in distributed environments, we need to understand the information needs of users. The purpose of this descriptive study was to document the communication of an operating room charge nurse to inform the design of technological communication applications for operating room coordination. A data collection tool was developed to record: 1) the purpose of the communication, 2) mode of communication, 3) the target individual, and 4) the length of time taken for each occurrence. The chosen data collection categories provided a functional structure for data collection and analysis involving communication. Study findings are discussed within the context of application design.

Communication↗

PubMed2001

[The survey of HIV prevalence among children between 0 to 7 years old in one county in China].

OBJECTIVE: To estimate the HIV prevalence among children between 0 to 7 years old in one county with HIV epidemic. METHODS: In September 2000, finger tip blood samples were collected from 619 children between 0 to 7 years old in three districts of one county with high HIV prevalence and tested for HIV antibody and HBV antigen. RESULTS: Among those 619 children, 11 were found HIV positive, with the prevalence of 1.8% (11/169). The HIV prevalence of three districts were 5.9% (10/169), 0.5% (1/206), and 0% (0/244), respectively. The possible channel associated with the HIV infection was mother-to-child transmission since none of the infected children had the history of blood transfusion. Twenty-four tested children were found HBV positive and the prevalence was 4.3 (24/619). CONCLUSION: There was higher HIV prevalence in children between 0 to 7 years old in certain areas. More intervenes are needed in the future to prevent the HIV spreading through mother-to-child transmission.

Child↗

PubMed2001

[Effects of olive oil and fish oil on serum lipids and lipid peroxidation in rats].

The effects of olive oil and fish oil on serum lipids and lipid peroxidation were studied in rats. The rats were divided into four groups: negative control, high fat control, fish oil (high fat diet and tube feeding with fish oil 4 ml.kg-1.d-1) and olive oil (high fat diet and tube feeding with olive oil 4 ml.kg-1.d-1) groups. The results showed that the total serum cholesterol and the triglyceride decreased significantly both in fish oil group and olive oil group, and there was a significant increase of serum high-density-lipoprotein (HDL) cholesterol in fish oil group. Both fish oil and olive oil increased superoxide dismutase (SOD) in erythrocyte and decreased serum MDA.

Animals↗

PubMed2001

[A dietary intervention study on the hypertensive high risk population in a northern rural area of Beijing].

To investigate the relationship between optimal living mode, healthy dietary pattern and the incidence of primary hypertension, a dietary intervention study on hte hypertensive high risk population was carried out in Fangshan district of Beijing during 1997-1999. The subjects were divided into two groups: control group and intervention group. A 3-day-dietary-recall combined with weighing method and a healthy diet education program were used in the study. The results indicated that the dietary pattern was not reasonable in the hypertensive high risk population. After two-year-intervention, the dietary pattern of people in the intervention group has changed distinctively. Compared with the results in 1997, the dietary risk factors decreased obviously in the intervention group, but increased in control group, such as high energy, fat, oil and cholesterol which can promote hypertension. Furthermore, in the past two years, the number of over weight + obese people increased by 24.6% in control group, but was no change in the intervention group. The intervention group subjects experienced an average decline of 3.7 and 5.1 mmHg of systolic blood pressure(SBP) and diastolic blood pressure(DBP) respectively, and new cases of hypertension observed in the intervention group were significantly lower than in control group. Thus it can be considered that the dietary intervention may be effective for the high risk population and play a very important role in the prevention of hypertension.

Adult↗

PubMed2001

[Contents analysis of zinc, manganese, copper and iron in 7 kinds of treatment gastritis Chinese traditional medicines].

The contents of Zn, Mn, Cu and Fe in 7 kinds of treatment gastritis Chinese traditional medicines are determined by FAAS. The results show that element Fe in medicines is very rich, but element Cu is lower. The relationship between trace elements and the factor that causes gastritis is discussed. It provides useful reference data for discussing the relations of trace elements and treatment of gastroenteritis.

Copper↗

PubMed2000

Local blockade of allergic airway hyperreactivity and inflammation by the poxvirus-derived pan-CC-chemokine inhibitor vCCI.

Allergen-induced asthma is characterized by chronic pulmonary inflammation, reversible bronchoconstriction, and airway hyperreactivity to provocative stimuli. Multiple CC-chemokines, which are produced by pulmonary tissue in response to local allergen challenge of asthmatic patients or experimentally sensitized rodents, chemoattract leukocytes from the circulation into the lung parenchyma and airway, and may also modify nonchemotactic function. To determine the therapeutic potential of local intrapulmonary CC-chemokine blockade to modify asthma, a recombinant poxvirus-derived viral CC-chemokine inhibitor protein (vCCI), which binds with high affinity to rodent and human CC-chemokines in vitro and neutralizes their biological activity, was administered by the intranasal route. Administration of vCCI to the respiratory tract resulted in dramatically improved pulmonary physiological function and decreased inflammation of the airway and the lung parenchyma. In contrast, vCCI had no significant effect on the circulating levels of total or allergen-specific IgE, allergen-specific cytokine production by peripheral lymph node T cells, or peritoneal inflammation after local allergen challenge, indicating that vCCI did not alter systemic Ag-specific immunity or chemoattraction at extrapulmonary sites. Together, these findings emphasize the importance of intrapulmonary CC-chemokines in the pathogenesis of asthma, and the therapeutic potential of generic and local CC-chemokine blockade for this and other chronic diseases in which CC-chemokines are locally produced.

Administration, Intranasal↗