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Biomedical subjects

Y C Zhang

Publications and source records attributed to Y C Zhang.

At least 19 recordsLinked to original sources

Optimum ratio of histidine in the piglet ideal protein model and its effects on body metabolism. I. Basal diet formulation based on digestible amino acids according to the ideal protein model for 10 to 20 kg piglets.

A 4 x 4 Latin square design was used to determine ileal apparent digestibility of amino acids (AAs) in corn, soybean meal, feather meal and dried whey in young pigs. The data were then to be used in formulating a basal diet for studies on AA metabolism in young pigs. Eight castrates T-cannulated at terminal ileum (average initial body weight 12.5 +/- 0.62 kg) were divided into 4 groups on the basis of body weight and transferred to individual metabolism crates. They were then fed four experimental diets containing the four feedstuffs to be tested (corn, soybean meal, feather meal and dried whey). The trial lasted 20 days, which included 4 five-day periods for ileal digesta collection. It was found that the digestibility of the AAs was similar to that reported in literature. Based on the findings a basal diet for this research was formulated according to an ideal protein model for the 10 to 20 kg piglet, on the basis of digestible AAs and containing 14.13 MJ/kg digestible energy, 18.22% crude protein, 1.04% digestible lysine and 0.23% digestible histidine.

Amino Acids↗

Extracting hidden information from knowledge networks.

We develop a method allowing us to reconstruct individual tastes of customers from a sparsely connected network of their opinions on products, services, or each other. Two distinct phase transitions occur as the density of edges in this network is increased: Above the first, macroscopic prediction of tastes becomes possible; while above the second, all unknown opinions can be uniquely reconstructed. We illustrate our ideas using a simple Gaussian model, which we study using both field-theoretical methods and numerical simulations. We point out a potential relevance of our approach to the field of bioinformatics.

Consumer Behavior↗

Adeno-associated virus vector-mediated IL-10 gene delivery prevents type 1 diabetes in NOD mice.

The development of spontaneous autoimmune diabetes in nonobese diabetic (NOD) mice provides for their use as a model of human type 1 diabetes. To test the feasibility of muscle-directed gene therapy to prevent type 1 diabetes, we developed recombinant adeno-associated virus (rAAV) vectors containing murine cDNAs for immunomodulatory cytokines IL-4 or IL-10. Skeletal muscle transduction of female NOD mice with IL-10, but not IL-4, completely abrogated diabetes. rAAV-IL-10 transduction attenuated the production of insulin autoantibodies, quantitatively reduced pancreatic insulitis, maintained islet insulin content, and altered splenocyte cytokine responses to mitogenic stimulation. The beneficial effects were host specific, as adoptive transfer of splenocytes from rAAV IL-10-treated animals rapidly imparted diabetes in naive hosts, and the cells contained no protective immunomodulatory capacity, as defined through adoptive cotransfer analyses. These results indicate the utility for rAAV, a vector with advantages for therapeutic gene delivery, to transfer immunoregulatory cytokines capable of preventing type 1 diabetes. In addition, these studies provide foundational support for the concept of using immunoregulatory agents delivered by rAAV to modulate a variety of disorders associated with deleterious immune responses, including allergic reactions, transplantation rejection, immunodeficiencies, and autoimmune disorders.

Adjuvants, Immunologic↗

[PLA2 activity in serum and cutaneous tissues in patients with psoriasis vulgaris].

We examined the activity of PLA2 by quick simple trace titration method in the serum and cutaneous tissues in patients with psoriasis vulgaris patients than that in the control group. The activity of PLA2 was significantly higher in psoriasis vulgaris patients than that in the control group. PLA2 activity in sera of psoriasis patients in the active stage or rash area > 30% was higher than that in the inactive stage or rash area < 30%. It is suggested that the sera PLA2 activity may be related to the disease activity in patients with psoriasis vulgaris, and PLA2 may play an important role in the pathogenesis of the psoriasis.

Adolescent↗

Relationship between phenotypes of cell-function differentiation and pathobiological behavior of gastric carcinomas.

AIM: To reveal the correlation between the functional differentiation phenotypes of gastric carcinoma cells and the invasion and metastasis by a new way of cell-function classification. METHODS: Surgically resected specimens of 361 gastric carcinomas(GC) were investigated with enzyme-, mucin-, and tumor-related marker immunohistochemistry. According to the direction of cell-function differentiation, stomach carcinomas were divided into five functionally differentiated types. RESULTS: (1) Absorptive function differentiation type (AFDT): there were 82 (22.7%) patients including 76 (92.7%) aged 45 years. Sixty-nine (84.1%) cases belonged to the intestinal type. Thirty-eight (46.3%) expressed CD44v6 and 9 (13.6%) of 66 male patients developed liver metastasis. The 5-year survival rate of patients in this group (58.5%) was higher than those with the other types (P<0.01). (2) Mucin secreting function differentiation type (MSFDT): 54 (15%) cases. Fifty-three (98.1%) tumors had penetrated the serosa, 12 (22.2%) expressed ER and 22 (40.7%) expressed CD44v6. The postoperative 5-year survival rate was 28.6%. (3) Absorptive and mucin-producing function differentiation type (AMPFDT): there were 180 (49.9%) cases, including 31 (17.2%) aged younger than 45 years. The tumor was more common in women (62, 34.4%,) and expressed more frequently estrogen receptors (ER) (129, 81.7%) than other types (P<0.01). Ovary metastasis was found in 12 (19.4%) out of 62 female subjects. The patients with this type GC had the lowest 5-year survival rate (24.7%) among all types. (4) Specific function differentiation type (SFDT): 13 (3.6%) cases. Nine (69.2%) tumors of this type derived from APUD system, the other 4 (30.7%) were of different histological differentiation. Sixty per cent of the patients survived at least five years. (5) Non-function differentiation type (NFDT): 32 (8.9%) cases. Nineteen (59.4%) cases had lymph node metastases but no one with liver or ovary metastasis. The 5-year survival rate was 28.1%. CONCLUSION: This new cell-function classification of GC is helpful in indicating the characteristics of invasion and metastasis of GC with different cell-function differentiation phenotypes. Further study is needed to disclose the correlation between the cell-functional differentiation phenotypes and the relevant genotypes and the biological behavior of gastric carcinoma.

Biomarkers, Tumor↗

[Study on the specificity of complement C5 for the postmortem diagnosis of myocardial infarction].

In order to explore the specificity of complement C5 in the postmortem diagnosis of myocardial infarction, changes of C5 staining in normal, infarcted and other non-infarcted myocardia with direct or indirect myocardial injuries (myocarditis, mechanical asphyxia, electrocution, hemorrhagic shock, cardiac contusion and organophosphate poisoning) were studied with immunohistochemistry and image analysis. The results showed that positive C5 staining could be observed in groups of myocardial infarction and myocarditis, but not in groups of mechanical asphyxia, electrocution, hemorrhagic shock, cardiac contusion, and organophosphate poisoning. It is indicated that positive reaction of C5 could only be affected by myocarditis, which means that it was more specific for the diagnosis of myocardial infarction.

Adolescent↗

[Immune functional changes in patients of acute Henoch-Schonlein purpura and regulatory effect of integrated Traditional Chinese and Western medicine on it].

OBJECTIVE: To observe the changes of immune function in children with acute Henoch-Schonlein purpura (AHSP) and the effects of integrated traditional Chinese and western medicine (TCM-WM) on it. METHODS: Immunological criteria in TCM-WM group (n = 35) treated by Yinfu Decoction (YFD) combined with transfer factor and 35 patients in the control group (n = 35) treated by conventional treatment were observed and compared before and after treatment. Also the criteria were compared with those of 40 healthy subjects. RESULTS: Before treatment, the levels of IgA, IgM, CD4, CD4/CD8 ratio, rosette forming rate of RBC-C3b receptor in patients were higher than those in the healthy subjects, but the levels of CD8 was obviously lower, the difference was significant (P < 0.01). The above-mentioned criteria were all improved in the two treated groups after treatment, and the improvement was more significant in the TCM-WM group than that in the control group (P < 0.05). Besides, the cure-markedly effective rate in the former was better than that in the latter significantly (P < 0.01). CONCLUSION: There exist multiple immune functional disturbance in AHSP patients. Combined treatment of YFD and transfer factor has obvious immune regulatory effect and is an effective therapy with few side-effects and low recurrence rate.

Adolescent↗

[Effects of fluid percussion injury on intracellular [Ca2+]i and pH in cultured rat neurons].

AIM: To study the change of intracellular [Ca2+]i and pH in cultured neurons after fluid percussion injury, and the therapeutic effect of drugs. METHODS: The neurons of Sprague Dawley rats were cultured for 8-14 days, then treated them with fluid percussion injury (2.5 kPa, 20 ms). Alterations of [Ca2+]i and pH in single neural cells following fluid percussion injury were measured by a laser scanning confocal microscope. After being injured for several hours the cultured neurons were treated with nimodipine or D-(-)-2-amino-5-phosphonovaleric acid (D-AP-5). Two hours later, the effects of drugs on intracellular [Ca2+]i and pH were studied. RESULTS: The Intracellular [Ca2+]i increased quickly after brain injury and reached peak in 12 hours. It then decreased gradually and became normal at 48 hours. The pH decreased slowly, reached minimum in 12 hours, and then kept at a lower level. It did not recover normal at 48 hours. Nimodipine and D-AP-5 decreased significantly the ascension of [Ca2+]i and the descent of pH. But nimodipine and D-AP-5 must be given within 10 hours after injury for a good therapeutic effect. CONCLUSION: According to the change of intracellular [Ca2+]i and pH, early use of nimodipine and D-AP-5, will get a better therapeutic effect.

2-Amino-5-phosphonovalerate↗

[Compound EPSPs and action potential of mauthner cell evoked by skin stimulation in crucian carp].

OBJECTIVE: To investigate the effects of afferent excitatory inputs from skin on the excitability of Mauthner cell (M cell) of crucian carp. METHODS: Multiple-site intracellular recordings on the soma and the ventral dendrite (VD) of M cell and direct current stimulation on the skin surface of the fish's trunk were employed. RESULTS: Direct stimulation of the skin evoked 3 groups of compound excitatory postsynaptic potentials (EPSPs) on soma and VD of M cell. Group a EPSP had the lowest amplitude (< or = 0.35 mV), which was insensitive to high-frequency stimulation. It had the shortest latency (mean 1.9 ms) and could be recorded on the soma and the proximal end of VD. Group b EPSP had the highest amplitude (< or = 9.7 mV), which was increased when the recording electrode was moved from the soma to the distal end of VD. The latency of Group b (mean 4.5 ms) was shorter than that of Group c, but longer than that of Group a. We firstly found that action potential could be induced on the basis of Group b in M cell by skin stimulation. Group c EPSP was our new finding, which could only be evoked by higher intensity (noxious) stimulus (> or = 100 V). It had the longest latency (mean 13.5 ms) with amplitude between those of a and b, and was very sensitive to high frequency stimulation. All the three groups of EPSPs were superimposed with spike-like transient potentials, which were believed to be the sign of electrical synapse activities. CONCLUSIONS: (1) Action potential can be induced on M cell by skin stimulation, which is in controversy with previous reports; (2) the noxious skin stimulation can induce a late EPSP (Group c) in M cell; (3) the neural pathway projecting from skin to M cell is composed of a set of neuronal chains with different number of synaptic relays, in which short chains projected concentrically to the soma and the proximal part of VD, while long chains projected mainly to the distal part of VD; (4) both electrical and chemical synapses may exist in short and long pathways.

Afferent Pathways↗

Ultrastructure of the post-corpus of Zeldia punctata (Cephalobina) for analysis of the evolutionary framework of nematodes related to Caenorhabditis elegans (Rhabditina).

The ultrastructure of the post-corpus of Zeldia punctata (Cephalobina) was compared with previous observations of Caenorhabditis elegans (Rhabditina) and Diplenteron sp. (Diplogastrina) with the goal of interpreting the morphological evolution of the feeding structures in the Secernentea. The post-corpus of Z. punctata consists of six marginal, 13 muscle, five gland and seven nerve cells. The most anterior of four layers of muscle cells consists of six mononucleate cells in Z. punctata. The homologous layer in C. elegans and Diplenteron consists of three binucleate cells, suggesting a unique derived character (synapomorphy) shared between the Rhabditina and Diplogastrina. Contrary to Diplenteron sp. where we observed three oesophageal glands, Z. punctata and C. elegans have five oesophageal glands. We question this shared character as reflecting a common evolution between the Cephalobina and Rhabditina, because there are strong arguments for functional (adaptive) convergence of the five glands in these bacterial feeders. Convergence is further suggested by the mosaic distribution of three versus five glands throughout the Nemata; this distribution creates difficulties in establishing character polarity. Although morphological data are often laborious to recover and interpret, we nevertheless view 'reciprocal illumination' between molecular and morphological characters as the most promising and robust process for reconstructing the evolution of the Secernentea and its feeding structures.

Animals↗

Antisense inhibition of beta(1)-adrenergic receptor mRNA in a single dose produces a profound and prolonged reduction in high blood pressure in spontaneously hypertensive rats.

BACKGROUND: beta-Blockers are the first line of therapy for hypertension. However, they are associated with side effects because of central nervous system (CNS) effects and beta(2)-adrenergic antagonism. To overcome these problems and provide a long-term beta(1)-blockade, antisense oligonucleotides against rat beta(1)-adrenergic receptor (beta(1)-AR) mRNA (beta(1)-AS-ODN) were designed and tested for the ability to inhibit cardiac beta(1)-ARs as well as lower blood pressure in spontaneously hypertensive rats (SHRs). METHODS AND RESULTS: Radioligand binding assay showed that a single intravenous injection of beta(1)-AS-ODN delivered in cationic liposomes significantly decreased cardiac beta(1)-AR density by 30% to 50% for 18 days (P<0.01), with no effect on beta(2)-ARs. This was accompanied by marked attenuation of beta(1)-AR-mediated positive inotropic response in isolated perfused hearts in vitro (P<0.02) and in conscious SHRs monitored by telemetry in vivo (P<0.02). Furthermore, the blood pressure of SHRs was reduced for 20 days, with a 38 mm Hg maximum drop. Heart rate was not significantly decreased. Quantitative autoradiography was performed to assess beta(1)-AS-ODN effects on the CNS, which demonstrated no changes in beta(1)-ARs in brain, in contrast to a significant reduction in heart and kidney (P<0.05). For comparison with beta-blockers, the effects of atenolol on cardiovascular hemodynamics were examined, which lowered blood pressure for only 10 hours and elicited appreciable bradycardia in SHRs. CONCLUSIONS: These results indicate that beta(1)-AS-ODN, a novel approach to specific beta(1)-blockade, has advantages over currently used beta-blockers in providing a profound and prolonged reduction in blood pressure without affecting heart rate, beta(2)-ARs, and the CNS. Diminished cardiac contractility resulting from less beta(1)-AR expression contributes to the antihypertensive effect.

Adrenergic beta-1 Receptor Antagonists↗

Protection against myocardial dysfunction induced by global ischemia-reperfusion by antisense-oligodeoxynucleotides directed at beta(1)-adrenoceptor mRNA.

Plasma catecholamine levels rise, and myocardial beta(1)-adrenoceptor (beta(1)-AR) sensitivity increases during ischemia. These factors enhance myocardial injury and cardiac dysfunction. beta(1)-AR blockers are clinically used to protect heart against ischemia and to improve cardiac dysfunction in patients with ischemic heart disease, but these agents often cause intolerable side effects. To examine the potential cardioprotective effect of therapy with antisense-oligodeoxynucleotides directed at beta(1)-AR mRNA (beta(1)-AS-ODNs) during myocardial ischemia-reperfusion, Sprague-Dawley rats were treated with beta(1)-AS-ODNs or inverted-oligodeoxynucleotides (IN-ODNs), each 200 microg/rat. Hearts were excised, perfused, and subjected to global ischemia (30 min) followed by reperfusion (30 min). Other rats were given selective beta(1)-AR blocker atenolol (2 mg/kg) or saline before excising the hearts. Ischemia-reperfusion resulted in cardiac dysfunction, indicated by an increase in coronary perfusion pressure and left ventricular end-diastolic pressure and a decrease in developed left ventricular pressure, as well as evidence of lipid peroxidation in saline-treated rats (all P <.05 versus control values). Administration of AS-ODNs or atenolol, but not IN-ODNs, protected hearts against functional deterioration and lipid peroxidation (P <.05 versus saline or IN-ODNs treatment). AS-ODNs therapy appeared to be equivalent to atenolol in these effects. Expression of beta(1)-AR protein as well as mRNA in the myocardium were markedly up-regulated after ischemia-reperfusion, and treatment with beta(1)-AS-ODNs, but not atenolol, decreased the rise in enhanced expression of beta(1)-AR. These observations imply that beta(1)-AS-ODNs can ameliorate cardiac dysfunction after ischemia-reperfusion by reducing the expression of beta(1)-AR in the ischemic-reperfused myocardium.

Animals↗

Adaptive response of thymocyte apoptosis and cell cycle progression induced by low dose X-ray irradiation in mice.

The dose-effect of adaptive response of thymocyte apoptosis and cell cycle progression induced by whole-body X-ray irradiation (WBI) was studied in male Kunming mice. The inductive doses (D1) were 25, 50, 75, 100 or 200 mGy 6 h before the challenging doses (D2) of 1.0, 1.5 or 2.0 Gy. The changes in the percentages of the thymocyte apoptotic bodies (TAB) and the cells in different phases of cell cycle were measured with flow cytometry. The percentages of TAB decreased, the arrests of G1 and G2 + M phases diminished, and the cells of DNA synthesis of S phase increased when the D1 + D2 groups was compared with the D2 groups. When D1 was 200 mGy, the adaptive response of thymocyte apoptosis and cell cycle progression were no longer induced by low dose radiation (LDR). In addition, the extracellular fluid from the splenocytes were cultured with Con A for 48 h in vitro 24 h after 75 mGy WBI was placed in the murine thymocyte suspension from mice irradiated with 2.0 Gy WBI and co-incubated. The thymocyte apoptosis decreased. Especially, noteworthy was that the percentages of TAB after the incubation for 72 h were significantly lower than those in 2.0 Gy irradiated thymocytes (P < 0.05). These results indicate that when the mice were irradiated with 25-100 mGy (D1, 12.5 mGy/min) 6 h before 1.0-2.0 Gy (D2, 0.287 Gy/min) exposure, an adaptive response of thymocyte apoptosis and cell cycle progression may be induced under the condition of WBI, and LDR (75 mGy) may change the microenvironment of immune cells and decrease the thymocyte apoptosis.

Animals↗

Upregulation of endothelial receptor for oxidized low-density lipoprotein (LOX-1) in cultured human coronary artery endothelial cells by angiotensin II type 1 receptor activation.

Cross talk between oxidized LDL (ox-LDL) and angiotensin II (Ang II) may be relevant in atherosclerosis. In this study, we examined the presence of a specific endothelial receptor for ox-LDL (LOX-1) and Ang II receptors in human coronary artery endothelial cells (HCAECs). In addition, we studied the effect of Ang II on LOX-1 gene and protein expression. LOX-1 was consistently identified in HCAECs by reverse transcriptase-polymerase chain reaction (RT-PCR), cDNA sequence, Western blot, and 125I-labeled ox-LDL binding assay (Bmax, 29.7 ng/mg protein). The HCAECs also exhibited Ang II receptors (AT1>AT2), as determined by RT-PCR and 125I-labeled Ang II binding assay (Bmax, 2.21 and 1.19 fmol/mg protein, respectively). Incubation of HCAECs with Ang II markedly increased LOX-1 mRNA (RT-PCR) and protein (Western blot) expression. The increase in LOX-1 expression was dependent on Ang II concentration (10(-12) to 10(-6) mol/L). Ang II caused a concentration-dependent increase in 125I-labeled ox-LDL uptake by HCAECs and enhanced ox-LDL-mediated cell injury, as evident from an increase in LDH release and a decrease in cell viability. These effects of Ang II were completely blocked by pretreatment of HCAECs with losartan, a specific AT1 blocker, but not by PD123319, a specific AT2 blocker. These observations indicate the following: (1) HCAECs possess abundant LOX-1 as well as Ang II (AT1>AT2) receptors, (2) Ang II upregulates LOX-1 receptor and ox-LDL uptake, (3) the effects of Ang II are mediated by AT1 activation, and (4) Ang II enhances ox-LDL-mediated injury to HCAECs.

Angiotensin II↗

Intravenous angiotensinogen antisense in AAV-based vector decreases hypertension.

Angiotensinogen (AGT) has been linked to hypertension. Because there are no direct inhibitors of AGT, we have developed antisense (AS) inhibition of AGT mRNA delivered in an adeno-associated virus (AAV)-based plasmid vector. This plasmid, driven by the cytomegalovirus promoter, contains a green fluorescent protein reporter gene and AS cDNA for rat AGT. Transfection of the plasmid into rat hepatoma cells brought a strong expression of the transgenes and a significant reduction in the level of AGT. In the in vivo study, naked plasmid DNA was intravenously injected into adult spontaneously hypertensive rats at different doses (0.6, 1.5, and 3 mg/kg). Expression of AGT AS mRNA was present in liver and heart, and it lasted longer in the liver. All three doses produced a significant decrease in blood pressure (BP). BP decreased for 2, 4, and 6 days, respectively. The lowest dose decreased BP by 12 +/- 3.0 mmHg, whereas the higher doses decreased BP by up to 22.5 +/- 5.2 mmHg compared with the control rats injected with saline (P < 0.01). The injection of the plasmid with liposomes produced a more profound and longer reduction (8 days) in BP. Consistent changes in plasma AGT level were observed. Sense plasmid had no effect. No liver toxicity was observed after injection of AS plasmid with or without liposomes. Our results suggest that the systemic delivery of AS against AGT mRNA by AAV-based plasmid vector, especially with liposomes, may have potential for gene therapy of hypertension and that further studies with the plasmid packaged into a recombinant AAV vector for a longer-lasting AS effect are warranted.

Angiotensinogen↗

Critical role of AT1 receptor expression after ischemia/reperfusion in isolated rat hearts: beneficial effect of antisense oligodeoxynucleotides directed at AT1 receptor mRNA.

To examine the relevance of angiotensin II type 1 receptor (AT1R) expression in the determination of myocardial function after ischemia/reperfusion, Sprague-Dawley rats were treated intravenously with antisense oligodeoxynucleotides (AS-ODNs) directed at AT1R mRNA (100 microg/rat, n=9) or scrambled antisense oligodeoxynucleotides (Scr-ODNs, 100 microg/rat, n=6). Both AS-ODNs and Scr-ODNs were given along with 300 microg/rat of liposome DOTAP/DOPE, a positive electron carrier (wt:wt= 1:1). The hearts from AS-ODN- or Scr-ODN-treated rats were excised 24 hours later, perfused in vitro, and subjected to 25 minutes of global ischemia followed by 30 minutes of reperfusion. Parallel groups of rats were given the specific AT1R antagonist losartan (10 mg/kg IV, n=6) or saline (n=7) 4 to 6 hours before excising the hearts. Ischemia/reperfusion resulted in a significant increase in myocardial AT1R expression (autoradiography and binding assay) and myocardial dysfunction, indicated by increases in coronary perfusion pressure and left ventricular end-diastolic pressure and a decrease in developed left ventricular pressure (all P<0.01 versus baseline) in the saline-treated group. AT1R protein and mRNA levels also increased in ischemic/ reperfused myocardial tissues. Administration of AS-ODNs or losartan, but not Scr-ODNs, preserved myocardial function and blocked the increased AT1R binding after ischemia/reperfusion (both P<0.01). Myocardial AT1R mRNA levels were not affected by either AS-ODNs or losartan, and the AT1R protein levels were significantly reduced by AS-ODN, but not losartan, treatment. Plasma angiotensin II levels increased after administration of losartan but not after administration of AS-ODNs. These observations imply a critical role of AT1R upregulation in determining myocardial function immediately after ischemia/reperfusion. AS-ODNs to AT1R mRNA may be more beneficial than losartan, because losartan does not affect the plasma angiotensin II level. The sustained increase in AT1R mRNA, but diminished protein expression, in rat hearts treated with AS-ODNs suggests that AS-ODNs block AT1R at the translational level.

Analysis of Variance↗