A nomogram to predict major adverse cardiovascular events of patients with acute chest pain, Non-ST-segment deviation, and normal troponin concentrations.

OBJECTIVE: To explore the potential indicators including patients' characteristics, electrocardiogram (ECG), echocardiography, and serological assay in predicting the major adverse cardiovascular events (MACE) within 1 year for patients with low-risk chest pain with a nomogram. PATIENTS AND METHODS: The detected indicators of patients with low-risk chest pain were obtained as the alternative predictors for MACE. After the 1-year follow-up, patients with MACE were enrolled in the MACE group while the remained patients were in the non-MACE group. A nomogram was constructed based on the multivariable Cox regression to link the independent predictors and the MACE within 1 year for patients with low-risk chest pain. RESULTS: The incidence of MACE within 1 year was 6.94% according to the follow-up result. Multivariate analysis revealed that risk factors of CAD, P-terminal force in lead V1 (PTFV1), C-reactive protein (CRP), and transmitral inflow early diastolic peak velocity (E wave) /peak early diastolic velocity (Em) (E/Em) were the independent predictors for the MACE. A nomogram incorporating these independent predictors with a good discrimination (0.79 in C-index) and calibration was constructed to predict the incidence of MACE within 1 year. It could be used to help select the patients with a high risk of MACE and develop preventive treatment strategies. CONCLUSIONS: Risk factors of CAD, PTFV1, CRP, and E/Em were the independent predictors for the MACE within 1 year in patients with low-risk chest pain. The present nomogram provides a user friendly tool in the prediction of MACE for these patients.

Protein-protein interaction network analysis of osteoarthritis-related differentially expressed genes.

The purpose of this study was to identify genes and pathways for osteoarthritis (OA) diagnosis and therapy. We downloaded the gene expression profile of OA from Gene Expression Omnibus (GEO) database including 10 early OA, 9 late OA, and 5 normal control samples. Next, we screened differentially expressed genes (DEGs) between early- and late-stage OA samples comparing with healthy control samples. Then, the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) software was used to construct protein-protein interaction (PPI) network, which was to predict the proteins that may interact with DEGs. The Gene Ontology (GO)-enrichment method was used to analyze the function of genes in the PPI networks. Meanwhile network module analysis was performed using Cytoscape. A total of 24 and 29 DEGs were identified for the early and late OA, respectively. TAC1 showed the highest degree in the PPI network. Functional annotation of the TAC1 network module indicated that this gene is associated with the G protein-coupled signal transduction pathway. In summary, TAC1, together with G protein-coupled receptors, appear to play a role in the biogenesis and progress of OA. Further analysis of this gene and pathway could therefore provide a potential target for the diagnosis and treatment of OA.

Effect of angiotensin II on STAT3 mediated atrial structural remodeling.

OBJECTIVE: Atrial fibrillation (AF) has been identified to contribute significantly to the morbidity and mortality of cardiovascular disease patients. The atrial structural remodeling is a hallmark of AF and the molecular mechanisms underlying this remain unclear. Hence the objective of the present study is to determine the role of angiotensin II (Ang-II)/Ang-II type 1 (AT1) receptor--STAT3 signaling pathway on--atrial structural remodeling. MATERIALS AND METHODS: The method of this study involves incubation of atrial myocytes, with Ang-II, to increase the level of apoptosis expressions by Tunel assay and the expression of apoptosis related factors like caspase 3 and 8 release of cytochrome C from mitochondria to cytosol by western blot test after OGD pre-treatment. RESULTS: Atrial myocytes were shown to simulate the ischemia, hypoxia and atrial fibrillation. When incubated with Ang-II, (inhibited by losartan) the improvement was observed in the expression of caspase-3 and caspase-8. Ang-II also significantly promoted the transfer of cytochrome C levels from the mitochondria to the cytoplasm and this transfer was observed to be inhibited by losartan and WP1066. Ang-II incubation showed improved transcriptions of collagens and MMP expressions in atrial fibroblasts. In cultured atrial myocytes and fibroblasts, Ang-II induced tyrosine and serine phosphorylation of STAT3 showing interaction with MMP1 and MMP2 and DNA promoter sequences in atrial fibroblasts. The complete sequence was observed to have an affinity to be inhibited by losartan and WP1066. CONCLUSIONS: Ang-II/AT1 receptor/STAT3 is an important signaling pathway in the atrial structural remodeling, Ang-II enhances the apoptosis of atrial parenchyma and deposition of atrial ECM, which might contributes to atrial fibrillation.

Changes in hippocampal synapses and learning-memory abilities in a streptozotocin-treated rat model and intervention by using fasudil hydrochloride.

Fasudil hydrochloride (FH), a Rho kinase inhibitor, is used to treat neurological diseases. This study aims to elucidate the anti-dementia role of FH in Alzheimer's disease. Twenty-four Sprague-Dawley rats were randomly divided into four groups: (1) sham-operated group (control), (2) sham-operated followed by FH administration group (sham+FH), (3) streptozotocin (STZ)-treated group (STZ), and (4) STZ treatment followed by FH administration group (STZ+FH). Rats in the STZ and STZ+FH groups received two divided doses of STZ (1.5 mg/kg) intracerebroventricularly on days 1 and 3, whereas control and sham+FH group rats were given citric acid/sodium citrate buffer. Rats in the sham+FH and STZ+FH groups were then treated intraperitoneally with FH (10 mg/kg) for 4 weeks, and rats in the STZ and control groups were treated with saline. Learning and memory were measured using the Morris water maze test. The synaptic ultrastructure in the CA1 region of the hippocampus was observed using electronic microscopy. The expression of synaptophysin (SYP) was measured using real-time polymerase chain reaction and western blot analyses; the expression of p-LIMK2 and p-cofilin were also detected using western blot analysis. The results indicate that STZ induced deficit in learning/memory, decrease in SYP expression, degeneration in synaptic structures, and increase in the expressions of p-LIMK2 and p-cofilin. These changes were reversed by the administration of FH, suggesting that FH has anti-dementia properties that protect synaptic structure and function. FH induced dephosphorylation (inactivation) of LIMK2 and subsequent dephosphorylation (activation) of cofilin, which may be responsible for the amelioration of neuronal synaptic structure and function.

[Relationship between insulin resistance and clustering of risk factors of cerebrovascular disease].

OBJECTIVE: To study the relationship between insulin resistance and clustering of risk factors of cerebrovascular disease. METHODS: The serum concentrations of fasting glucose, insulin, lipids, the activities of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1(PAI-1), and the level of blood pressure were measured in 159 patients with stroke and 40 healthy control subjects. RESULTS: All subjects were divided into 4 groups in the light of number of risk factors of cerebrovascular disease. As the number of risk factors increased, the insulin sensitivity index (ISI) in four groups gradually decreased. The ISI in the patients with cerebrovascular disease was negatively associated with increased levels of SBP, DBP, TG, APOB, and PAI-1 activity (P < 0.01) and positively with decreased level of HDL (P < 0.01). CONCLUSION: Insulin resistance is associated with clustering of risk factors of cerebrovascular disease, the more resistant, the more clustered.

[Kanamycin ototoxicity and melanin in the inner ear].

In order to clarify the relationship between ototoxicity of aminoglucoside and inner ear melanin, we have undergone observations on the cochleas of albino and pigmented guinea pigs with surface preparation, paraffin section. SEM and ECochG following chronic administration of kanamycin. The damage in the pigmented animal was more serious than that of the albino ones. It seems that the cochlea of the pigmented animal is more susceptible to kanamycin than that of the albino ones. It suggests that melanin may be implicated in the ototoxicity of aminoglucoside antibiotics that might be due to its capacity to take and accumulate the drug.

Monoclonal antibodies to ligand-occupied conformers of integrin alpha IIb beta 3 (glycoprotein IIb-IIIa) alter receptor affinity, specificity, and function.

Occupancy of integrin receptors induces conformational changes in the receptor, resulting in exposure of novel interactive sites termed ligand-induced binding sites (LIBS). We report here that Fab fragments of certain antibodies against LIBS on integrin alpha IIb beta 3 (platelet glycoprotein IIb-IIIa) block platelet aggregation. Thus, certain LIBS or the regions surrounding them may participate in events required for platelet aggregation. In addition, certain anti-alpha IIb beta 3 LIBS Fab fragments stimulated platelet aggregation. This was due to induction of fg binding to alpha IIb beta 3, apparently by shifting a conformational equilibrium between a "resting" and an "activated" state of alpha IIb beta 3. Some of the activating anti-LIBS Fab fragments also induced high affinity fibronectin binding to alpha IIb beta 3, whereas others did not. Thus, changes in the conformation of this integrin modulate both the specificity and affinity of ligand recognition.

Ligands "activate" integrin alpha IIb beta 3 (platelet GPIIb-IIIa).

Integrin alpha IIb beta 3 (platelet GPIIb-IIIa) binds fibrinogen via recognition sequences such as Arg-Gly-Asp (RGD). Fibrinogen binding requires agonist activation of platelets, whereas the binding of short synthetic RGD peptides does not. We now find that RGD peptide binding leads to changes in alpha IIb beta 3 that are associated with acquisition of high affinity fibrinogen-binding function (activation) and subsequent platelet aggregation. The structural specificities for peptide activation and for inhibition of ligand binding are similar, indicating that both are consequences of occupancy of the same site(s) on alpha IIb beta 3. Thus, the RGD sequence is a trigger of high affinity ligand binding to alpha IIb beta 3, and certain RGD-mimetics are partial agonists as well as competitive antagonists of integrin function.

Characterization of the binding domains on platelet glycoproteins Ib-IX and IIb/IIIa complexes for the quinine/quinidine-dependent antibodies.

Sera of 12 patients with quinine/quinidine-induced thrombocytopenia showed drug-dependent antibody binding to glycoprotein (GP) Ib-IX complex. The reaction with GPIb-IX complex of 11 of these 12 sera was strongly inhibited by the complex-specific monoclonal antibodies (MoAbs) AK1 and SZ1. The exception was a quinine-induced serum designated BU. The reaction of the six quinidine-induced sera was also partially blocked by an anti-GPIX MoAb, FMC25. Only 3 of the 12 patient sera showed drug-dependent antibody binding to GPIIb/IIIa, which was strongly inhibited by the anti-GPIIIa MoAb 22C4, and the anti-GPIIb alpha MoAb SZ22. With detergent-solubilized Serratia metalloprotease-treated platelets, quinine/quinidine-induced sera, except BU, immunoprecipitated a membrane-bound proteolytic fragment of GPIb-IX complex. In contrast, BU immunoprecipitated glycocalicin and a 40-Kd peptide tail fragment of GPIb alpha from the cell supernatant. Using purified GPIb-IX complex or its components as the target antigen, all the quinine-induced sera, except BU, immunoprecipitated GPIb-IX complex but failed to immunoprecipitate GPIb, GPIX, or the complex reformed from GPIb and GPIX. The quinidine-induced sera strongly immunoprecipitated purified GPIb-IX complex, weakly immunoprecipitated purified GPIX and the recombined complex, but did not immunoprecipitate purified GPIb. The combined data suggest that one quinine-dependent antibody (BU) recognizes an epitope in the peptide tail region of GPIb alpha and the other five quinine-dependent antibodies react with a complex-specific epitope on the membrane-associated region of GPIb-IX complex, whereas each of the six quinidine-induced sera contain two drug-dependent antibodies, one reactive with the GPIb-IX complex-specific epitope and the other reactive with GPIX. The binding domain(s) on GPIIb/IIIa for the quinine/quinidine-dependent antibodies appear to be sterically close to the epitopes for 22C4 and SZ22.

Affinity modulation of the alpha IIb beta 3 integrin (platelet GPIIb-IIIa) is an intrinsic property of the receptor.

To analyze the basis of affinity modulation of integrin function, we studied cloned stable Chinese hamster ovary cell lines expressing recombinant integrins of the beta 3 family (alpha IIb beta 3 and alpha v beta 3). Antigenic and peptide recognition specificities of the recombinant receptors resembled those of the native receptors found in platelets or endothelial cells. The alpha IIb beta 3-expressing cell line (A5) bound RGD peptides and immobilized fibrinogen (Fg) but not soluble fibrinogen or the activation-specific monoclonal anti-alpha IIb beta 3 (PAC1), indicating that it was in the affinity state found on resting platelets. Several platelet agonists failed to alter the affinity state of ("activate") recombinant alpha IIb beta 3. The binding of soluble Fg and PAC1, however, was stimulated in both platelets and A5 cells by addition of IgG papain-digestion products (Fab) fragments of certain beta 3-specific monoclonal antibodies. These antibodies stimulated PAC1 binding to platelets fixed under conditions rendering them unresponsive to other agonists. Addition of these antibodies to detergent-solubilized alpha IIb beta 3 also stimulated specific Fg binding. These data demonstrate that certain anti-beta 3 antibodies activate alpha IIb beta 3 by acting directly on the receptor, possibly by altering its conformation. Furthermore, they indicate that the activation state of alpha IIb beta 3 is a property of the receptor itself rather than of the surrounding cell membrane microenvironment.

Ristocetin-dependent reconstitution of binding of von Willebrand factor to purified human platelet membrane glycoprotein Ib-IX complex.

Whether the human platelet membrane glycoprotein (GP) Ib-IX complex is the receptor for ristocetin-dependent binding of von Willebrand factor (vWF) has been examined by reconstitution with the purified components using a solid-phase bead assay. Purified GP Ib-IX complex was bound and orientated on the beads via a monoclonal antibody, FMC 25, directed against the membrane-associated region of the complex. Specific binding of 125I-labeled vWF to the GP Ib-IX complex coated beads was strictly ristocetin dependent with maximal binding occurring at ristocetin concentrations greater than or equal to 1 mg/mL. Ristocetin-dependent specific binding of 125I-labeled vWF was saturable. The observed binding was specific to the interaction between vWF and the GP Ib-IX complex since there was no ristocetin-dependent specific binding of vWF if the physicochemically related platelet membrane glycoprotein, GP IIb, was substituted for the GP Ib-IX complex in a corresponding bead assay. Further, neither bovine serum albumin nor other adhesive glycoproteins, such as fibrinogen or fibronectin, specifically bound to the GP Ib-IX complex in the presence of ristocetin. Ristocetin-dependent binding of vWF to platelets and to GP Ib-IX complex coated beads was inhibited by monoclonal antibodies against a 45,000 molecular weight N-terminal region of GP Ib but not by monoclonal antibodies directed against other regions of the GP Ib-IX complex. Similar correspondence between platelets and purified GP Ib-IX complex with respect to the ristocetin-dependent binding of vWF was obtained with anti-vWF monoclonal antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on monoclonal antibodies against human platelets--a monoclonal antibody to human platelet glycoprotein I--SZ-2.

A monoclonal antibody, SZ-2, reacts specifically on human platelets and megakaryocytes. The platelets from 10 normal donors are bound to 15,200 +/- 4,100 SZ-2 molecules/platelet. The antigen recognized by SZ-2 is chymotrypsin-sensitive but neuraminidase-insensitive, and has been identified as glycoprotein Ib (GPIb) by an affinity chromatography technique. SZ-2 is different from other monoclonal antibodies to GPIb. It inhibits not only platelet aggregation induced by ristocetin, but also platelet aggregation induced by collagen (type I) and by PAF. SZ-2 also inhibits platelet serotonin and beta-thromboglobulin release in response to these stimuli.

A murine antiglycoprotein Ib complex monoclonal antibody, SZ 2, inhibits platelet aggregation induced by both ristocetin and collagen.

A new monoclonal antibody (MoAb), SZ 2, reactive with the human platelet glycoprotein Ib complex has been produced by the hybridoma technique. SZ 2 immunoprecipitated the components of the glycoprotein Ib complex, glycoprotein Ib and glycoprotein IX, from Triton-X-100-solubilized, periodate-labeled platelets. Western blot analysis indicated that the epitope for SZ 2 was on the alpha-subunit of glycoprotein Ib. Scatchard analysis of SZ 2 binding to formaldehyde-fixed, washed platelets revealed a single class of binding sites with Kd = 6.6 +/- 3.3 X 10(-10) mol/L and 15,200 +/- 4,100 binding sites per platelet (mean +/- SD, n = 10). Intact antibody and its purified (Fab')2 fragments not only inhibited the ristocetin-dependent binding of von Willebrand factor to platelets and ristocetin-induced platelet agglutination but also inhibited platelet aggregation induced by Type I collagen and platelet-activating factor (PAF). SZ 2 inhibited platelet serotonin and beta-thromboglobulin release in response to these stimuli and also platelet thromboxane A2 formation in response to ristocetin and collagen. SZ 2 was without effect on platelet aggregation or release in response to other platelet stimuli such as ADP, thrombin, or arachidonic acid. The inhibition by SZ 2 of collagen- and PAF-induced platelet aggregation is surprising in that Bernard-Soulier syndrome platelets, which lack the glycoprotein Ib complex, respond normally to both these stimuli. SZ 2 was unreactive toward Bernard-Soulier syndrome platelets, as evaluated by fluorescence-associated cell sorting, and had no effect on the collagen- and PAF-induced aggregation of Bernard-Soulier syndrome platelets. The combined results suggest that the inhibition by SZ 2 of collagen- and PAF-induced aggregation of normal platelets is steric and are consistent with the glycoprotein Ib complex and the platelet collagen and PAF receptor(s) being adjacent in the human platelet plasma membrane.