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Calreticulin (CRT) is a major calcium-binding luminal resident protein on the endoplasmic reticulum that can also be released extracellular as well as anchored on surface of cells. Previously, we demonstrated that soluble recombinant CRT fragment 39-272 (CRT/39-272) exhibited potent immunostimulatory effects as well as immunoregulation effects on immune cells. Here, we constructed stable B16 melanoma cell lines expressing recombinant CRT/39-272 on the membrane (B16-tmCRT/39-272) to investigate the roles of cell surface CRT on tumor progression. We found that B16-tmCRT/39-272 cells subcutaneously inoculated into C57BL/6 mice exhibited stronger tumorigenicity than the B16-EGFP control cells. The tumor associated macrophages infiltrated in tumors were mainly M2 phenotype. Regulatory T cells (Tregs) were also expanded more in bearing mice. Consistent with the in vivo results, B16-tmCRT/39-272 promoted macrophage polarization toward F4/80+CD206+ M2 macrophages and promoted transforming growth factor beta (TGF-β) secretion in vitro, which could promote naïve CD4+T cell differentiation into Tregs. These results imply that the tmCRT/39-272 could accelerate tumor development by enhancing M2 macrophage polarization to induce TGF-β secretion, and then promoted Treg differentiation in the tumor microenvironment. Our data may provide useful clues for better understanding of the potentiating roles of CRT in tumorigenesis. [ABSTRACT FROM AUTHOR]

An endoplasmic reticulum resident protein, calreticulin (CRT), participates in many cellular processes. CRT is a tumor-associated antigen with an important role in antitumor immunity. Previously, we reported that the recombinant CRT fragment 39-272 (CRT/39-272) exhibited superior immunobiological activity, activating macrophages to release cytokines and promoting dendritic cell (DC) maturation. However, the effect of CRT/39-272 in vivo, especially its adjuvant effect on in vivo antitumor immune responses, was not fully investigated. In this study, we constructed a fusion protein linking CRT/39-272 to an ovalbumin (OVA) peptide (residues 182-297, OVAp) and used the fusion protein (OVAp-CRT) to examine the adjuvant effect of CRT. We investigated whether CRT/39-272 could induce bone marrow-derived DC maturation and strongly promote the proliferation of OVA-specific T cells in vitro. Compared with OVAp, OVAp-CRT induced stronger antigen-specific T lymphocyte responses, including antigen-specific T cell proliferation, interferon-γ secretion, and cytotoxic T lymphocyte responses. OVAp-CRT-immunized mice generated significantly increased OVAp-specific antibody and CD4+/CD8+ memory T cells, which mediated long-term protective effects. OVAp-CRT upregulated CD40, CD80, and CD86 expressions in splenic conventional DCs. Furthermore, OVAp-CRT protected immunized mice against OVA-expressing B16 melanoma cells in vivo. Moreover, mice that were adoptively transferred with OVAp-CRT-pulsed DCs showed inhibited tumor growth and prolonged mouse survival. Our results demonstrate that CRT/39-272 can be used as a potential new adjuvant for tumor vaccines, and this finding may be useful in tumor vaccine development. [ABSTRACT FROM AUTHOR]

Much evidence suggests that trained immunity is inappropriately activated in the synovial tissue in rheumatoid arthritis (RA), but the underlying mechanism remains unclear. Here, we describe how RA-specific autoantibody deposits can train human monocytes to exert the hyperactive inflammatory response, particularly via the exacerbated release of tumor necrosis factor α (TNFα). Comparative transcriptomic analysis by plate-bound human IgG (cIgG) or β-glucan indicated that metabolic shift towards glycolysis is a crucial mechanism for trained immunity. Moreover, the cIgG-trained gene signatures were enriched in synovial tissues from patients with ACPA- (anticitrullinated protein antibody-) positive arthralgia and undifferentiated arthritis, and early RA and established RA bore a great resemblance to the myeloid pathotype, suggesting a historical priming event in vivo. Additionally, the expression of the cIgG-trained signatures is higher in the female, older, and ACPA-positive populations, with a predictive role in the clinical response to infliximab. We conclude that RA-specific autoantibodies can train monocytes in the inflamed lesion as early as the asymptomatic stage, which may not merely improve understanding of disease progression but may also suggest therapeutic and/or preventive strategies for autoimmune diseases. [ABSTRACT FROM AUTHOR]

Soluble lactoferrin (LTF) is a versatile molecule that not only regulates the iron homeostasis, but also harbors direct microbicidal and immunomodulating abilities in mammalian body fluids. In contrast, little is known about the function of membrane-bound LTF (mbLTF), although its expression on human polymorphonuclear leukocytes (huPMNs) has been reported for decades. Given that LTF/anti-LTF antibodies represent a potential diagnostic/prognostic biomarker and a therapeutic target in patients with immune disorders, we wished, in the present study, to generate a novel human LTF- (huLTF-) specific mAb suitable for detailed analyses on the expression and function of mbLTF as well as for deciphering the underlying mechanisms. By using the traditional hybridoma cell fusion technology, we obtained a murine IgG1 (kappa) mAb, M-860, against huLTF. M-860 recognizes a conformational epitope of huLTF as it binds to natural, but not denatured, huLTF in ELISA. Moreover, M-860 detects mbLTF by FACS and captures endogenous huLTF in total cell lysates of huPMNs. Functionally, M-860 induces the activation of huPMNs partially through TLR4 but independently of phagocytosis. M-860 is thus a powerful tool to analyze the expression and function of human mbLTF, which will further our understanding of the roles of LTF in health and disease. [ABSTRACT FROM AUTHOR]

Adeno-associated virus ( AAV) has become one of the most promising gene transfer tools for gene therapy. This work aims to evaluate tropism, gene transfer efficiency and safety of AAV9 vectors produced with recombinant baculovirus ( rBac)-based system. AAV9- CMV- GFP and AAV9- CBA- GFP were produced using a rBac system, 1 × 1011 particles of each vectors were administered intravenously (i.v.) into mice and animals were killed at 1, 2, 3, 4, 5 and 8 weeks after administration. The GFP expression in different organs was analyzed by fluorescence imaging and Western blot. Viral genomic quantities were measured using qPCR. In vitro transduction efficiency of AAV9 vectors in primary cardiomyocytes and hepatocytes was determined by flow cytometry. Toxicity of AAV9 vectors was evaluated by determining certain cardiac and liver injury biomarkers and renal function test in vivo and TUNEL analysis in vitro. The data showed that AAV9 viral particles packaged by the rBac system were fully functional in vivo and in vitro. The CMV promoter predominantly induced higher cardiac GFP transgene expression and DNA copy numbers while the CBA promoter resulted in robust GFP expression and high vector DNA copy numbers in mouse liver, both in a time-dependent increased manner. Such distinct preferential effects were also observed in the heart and liver as early as 3 and 5 days after co-infection. Both the AAV9- CMV and AAV9- CBA viral packages did not induce heart, liver and renal damage and cell apoptosis. These results indicated that AAV9- CMV can efficiently and safely direct cardiac gene transfer, whereas AAV9- CBA is preferential for liver gene delivery. [ABSTRACT FROM AUTHOR]

β-adrenergic activation and angiogenesis are pivotal for myocardial function but the link between both events remains unclear. The aim of this study was to explore the cardiac angiogenesis profile in a mouse model with cardiomyocyte-restricted overexpression of β2-adrenoceptors ( β2- TG), and the effect of cardiac pressure overload. β2- TG mice had heightened cardiac angiogenesis, which was essential for maintenance of the hypercontractile phenotype seen in this model. Relative to controls, cardiomyocytes of β2- TGs showed upregulated expression of vascular endothelial growth factor ( VEGF), heightened phosphorylation of cAMP-responsive-element-binding protein ( CREB), and increased recruitment of phospho- CREB, CREB-binding protein ( CBP), and p300 to the VEGF promoter. However, when hearts were subjected to pressure overload by transverse aortic constriction ( TAC), angiogenic signaling in β2- TGs was inhibited within 1 week after TAC. β2- TG hearts, but not controls, exposed to pressure overload for 1-2 weeks showed significant increases from baseline in phosphorylation of Ca2+/calmodulin-dependent kinase II (Ca MKIIδ) and protein expression of p53, reduction in CREB phosphorylation, and reduced abundance of phospho- CREB, p300 and CBP recruited to the CREB-responsive element ( CRE) site of VEGF promoter. These changes were associated with reduction in both VEGF expression and capillary density. While non- TG mice with TAC developed compensatory hypertrophy, (2- TGs exhibited exaggerated hypertrophic growth at week-1 post- TAC, followed by LV dilatation and reduced fractional shortening measured by serial echocardiography. In conclusion, angiogenesis was enhanced by the cardiomyocyte (2 AR/ CREB/ VEGF signaling pathway. Pressure overload rapidly inhibited this signaling, likely as a consequence of activated Ca MKII and p53, leading to impaired angiogenesis and functional decompensation. [ABSTRACT FROM AUTHOR]

Background and Purpose: The β1-adrenoceptor has at least two binding sites, high and low affinity sites (β1H and β1L, respectively), which mediate cardiostimulation. While β1H-adrenoceptor can be blocked by all clinically used β-blockers, β1L-adrenoceptor is relatively resistant to blockade. Thus, chronic β1L-adrenoceptor activation may mediate persistent cardiostimulation, despite the concurrent blockade of β1H-adrenoceptors. Hence, it is important to determine the potential significance of β1L-adrenoceptors in vivo, particularly in pathological situations.Experimental Approach: C57Bl/6 male mice were used. Chronic (4 or 8 weeks) β1L-adrenoceptor activation was achieved by treatment, via osmotic mini pumps, with (-)-CGP12177 (10 mg·kg(-1)·day(-1)). Cardiac function was assessed by echocardiography and micromanometry.Key Results: (-)-CGP12177 treatment of healthy mice increased heart rate and left ventricular (LV) contractility. (-)-CGP12177 treatment of mice subjected to transverse aorta constriction (TAC), during weeks 4-8 or 4-12 after TAC, led to a positive inotropic effect and exacerbated fibrogenic signalling while cardiac hypertrophy tended to be more severe. (-)-CGP12177 treatment of mice with TAC also exacerbated the myocardial expression of hypertrophic, fibrogenic and inflammatory genes compared to untreated TAC mice. Washout of (-)-CGP12177 revealed a more pronounced cardiac dysfunction after 12 weeks of TAC.Conclusions and Implications: β1L-adrenoceptor activation provides functional support to the heart, in both normal and pathological (pressure overload) situations. Sustained β1L-adrenoceptor activation in the diseased heart exacerbates LV remodelling and therefore may promote disease progression from compensatory hypertrophy to heart failure. [ABSTRACT FROM AUTHOR]

Background and Purpose The β1-adrenoceptor has at least two binding sites, high and low affinity sites (β1H and β1L, respectively), which mediate cardiostimulation. While β1H-adrenoceptor can be blocked by all clinically used β-blockers, β1L-adrenoceptor is relatively resistant to blockade. Thus, chronic β1L-adrenoceptor activation may mediate persistent cardiostimulation, despite the concurrent blockade of β1H-adrenoceptors. Hence, it is important to determine the potential significance of β1L-adrenoceptors in vivo, particularly in pathological situations. Experimental Approach C57Bl/6 male mice were used. Chronic (4 or 8 weeks) β1L-adrenoceptor activation was achieved by treatment, via osmotic mini pumps, with (-)- CGP12177 (10 mg·kg−1·day−1). Cardiac function was assessed by echocardiography and micromanometry. Key Results (-)- CGP12177 treatment of healthy mice increased heart rate and left ventricular ( LV) contractility. (-)- CGP12177 treatment of mice subjected to transverse aorta constriction ( TAC), during weeks 4-8 or 4-12 after TAC, led to a positive inotropic effect and exacerbated fibrogenic signalling while cardiac hypertrophy tended to be more severe. (-)- CGP12177 treatment of mice with TAC also exacerbated the myocardial expression of hypertrophic, fibrogenic and inflammatory genes compared to untreated TAC mice. Washout of (-)- CGP12177 revealed a more pronounced cardiac dysfunction after 12 weeks of TAC. Conclusions and Implications β1L-adrenoceptor activation provides functional support to the heart, in both normal and pathological (pressure overload) situations. Sustained β1L-adrenoceptor activation in the diseased heart exacerbates LV remodelling and therefore may promote disease progression from compensatory hypertrophy to heart failure. [ABSTRACT FROM AUTHOR]

Although caltreticulin ( CRT) is mainly a residential ER protein, it is also expressed on the membrane surface of various types of cells exhibiting multiple functions. We report here that intraperitoneal administration of a soluble recombinant CRT fragment (r CRT/39-272) led to a substantial decrease in delayed type hypersensitivity (DTH) responses in BALB/c mice and EAE in C57 BL/6 mice. In the recall response against keyhole limpet hemocyanin (KLH) in vitro, draining lymph node cells from the rCRT/39-272-treated mice produced less IFN-γ but more IL-4 as compared with the cells from the control group. The immunomodulating effect of intraperitoneally administered r CRT/39-272 was attributed to anti- CRT Abs thereby induced, because, in passive transfer experiments, the CRT-specific antiserum could suppress DTH in BALB/c mice. B-cell-deficient μ MT mice were not susceptible to r CRT/39-272-mediated DTH suppression. Furthermore, CRT appears on the surface of murine T cells soon after activation and remains detectable (at relatively low level) by flow cytometry for approximately 5 days in vitro. Anti- CRT Abs were able to inhibit AKT phosphorylation, proliferation, and cytokine production by activated murine T cells. We propose that cell surface CRT could play a role in the function of effector T cells and may be considered a target for immunological manipulation. [ABSTRACT FROM AUTHOR]

ABSTRACT Fragment 450-650 of the spike (S) protein (S450-650) of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) contains epitopes capable of being recognized by convalescent sera of SARS patients. Vaccination of mice with recombinant S450-650 (rS450-650) can induce Abs against SARS-CoV, although the titer is relatively low. In the present study, a fusion protein linking a fragment (residues 39-272) of murine calreticulin (CRT) to S450-650 in a prokaryotic expression system was created. Compared with target antigen alone, the recombinant fusion product (rS450-650-CRT) has much improved hydrophilicity and immunogenicity. The S450-650-specific IgG Abs of BALB/c mice subcutaneously immunized with rS450-650-CRT were in substantially higher titer (approximately fivefold more). Furthermore, the fusion protein, but not rS450-650 alone, was able to elicit S450-650-specific IgG responses in T cell deficient nude mice. Given that rCRT/39-272 can drive the maturation of bone-marrow-derived dendritic cells, directly activate macrophages and B cells, and also elicit helper T cell responses in vivo, we propose that fragment 39-272 of CRT is an effective molecular adjuvant capable of enhancing target Ag-specific humoral responses in both a T cell-dependent and independent manner. Fusion protein rS450-650-CRT is a potential candidate vaccine against SARS-CoV infection. [ABSTRACT FROM AUTHOR]

1. Transition from compensated left ventricular (LV) hypertrophy to decompensated heart failure was characterized using a pressure-overload induced model to elucidate the temporal relationship between cardiomyocyte apoptosis and survival signalling in this transition. 2. Mice were subjected to transverse aortic constriction (TAC) or sham operation for 1–16 weeks and were studied by echocardiography, catheterization and histology. Relevant gene expression and phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, Akt and glycogen synthase kinase (GSK)-3β were determined. 3. Transverse aortic constriction resulted in myocyte hypertrophy and fibrosis from Week 4 and a progressive increase in left ventricular (LV) dimensions and wall thicknesses with maintained contractile function by Week 12. However, a sharp decline in contractile function and elevated LV end-diastolic pressure from 12 to 16 weeks were observed after TAC, indicating functional decompensation. 4. Following TAC, mRNA levels of atrial natriuretic peptide, B-type natriuretic peptide, β-myosin heavy chain (MHC) and transforming growth factor-β1 were increased time dependently, whereas mRNA expression of α-MHC, sarcoplasmic/endoplasmic reticulum calcium ATPase 2a and Bcl-2 were decreased. The ratio of Bcl-2/Bax was decreased and this was consistent with progressively increased myocyte apoptosis demonstrated by terminal deoxyribonucleotidyl transferase-mediated dUTP–digoxigenin nick end-labelling staining. Phosphorylation of ERK1/2 was increased by Week 4, but decreased thereafter. Levels of phosphorylated Akt declined from Week 8, whereas GSK3β phosphorylation increased from 1 to 8 weeks, then decreased from Week 12 after TAC. 5. In conclusion, TAC resulted in early concentric and late eccentric hypertrophy with eventual development of LV dysfunction. This transition was temporally associated with a progressive increase in cell size, fibrosis and myocyte apoptosis. Downregulation of ERK1/2, Akt and GSK3β and enhanced cardiomyocyte apoptosis are implicated as important mechanisms in the transition from compensated hypertrophy to heart failure. [ABSTRACT FROM AUTHOR]

As a hallmark of heart disease, cardiac fibrosis contributes to the development of heart failure and arrhythmias and forms a key therapeutic target. There is a major unmet need for selective, potent, and safe antifibrotic drugs. Earlier studies revealed a cardiac fibrosis phenotype in relaxin-1-deficient mice. Recent studies in several rodent models of cardiac fibrosis have documented reversal of fibrosis by treatment with relaxin peptide or virally mediated relaxin gene delivery. In mice with surgically induced transmural myocardial infarction, relaxin therapy inhibited scar density. In these studies, however, functional benefits achieved by relaxin therapy were limited or less explored. Collectively, there is good experimental evidence that relaxin is able to reverse cardiac fibrosis due to distinct mechanisms. Future research needs to explore functional improvement following fibrosis reversal by relaxin and the usefulness of relaxin in antiarrhythmic or stem cell-based therapy. [ABSTRACT FROM AUTHOR]

The 'Yang'-promoting traditional Chinese medicines (TCM) are used to boost vigor and enhance immunity in humans. In this study, the immunopotentiating effect of VI-28, a 'Yang'-promoting TCM formula containing extracts of radix ginseng, cornu Cervi pantotrichum and radix Salvia miltiorrhizae, was investigated. Groups of 8-month-old female ex-breeder BALB/c mice were fed on ordinary mouse food or food containing a low (0.5%) or high (2%) dose VI-28 for up to 18 weeks. From week 6, mice on the TCM-containing diet were much healthier, stronger and more alert than those on the normal mouse food. Furthermore, their thymuses were significantly bigger and heavier than those of the control mice. Histological examination revealed structural changes typical of thymic involution in mice of the control group, whilst the microstructure of thymuses from mice taking TCM-containing food was comparable to that of mice of a much younger age, indicating a positive effect of VI-28 on slowing down thymic involution. Functional analysis of splenocytes from mice of different groups suggested that oral administration of VI-28 corrected the hyporesponsiveness of T lymphocytes in aged mice. These results have important implications for our understanding of the mechanisms of the immunoboosting effect of TCM. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

1: Ivabradine selectively reduces heart rate (HR) by inhibiting the cardiac pacemaker If current, thus prolonging the duration of spontaneous depolarization in the sinus node. The activity of ivabradine under conditions of enhanced sympathoadrenergic activity has been addressed by investigating the effects of repeated oral administration in mice with sympathoadrenergic activation due to either stress, cardiac-restricted overexpression of ß2-adrenergic receptors (ß2AR), or ß-agonist administration. HR and left ventricular fractional shortening (FS) were determined by echocardiography. 2: Initial experiments showed that the conscious restrained state was associated with stress-mediated sympathetic activation, while sympathetic withdrawal occurred under anaesthetized conditions. In wild-type mice, ivabradine reduced HR under both conscious and anaesthetized states, with a similar degree in absolute reduction under both states. FS was unchanged by the treatment. 3: Ivabradine was similarly effective in reducing HR in the ß2AR transgenic mice. Further, ivabradine at 10?mg?kg-1?day-1 reduced the maximal HR increase in response to the ß-agonist isoproterenol, without modifying the response of contractile parameters. 4: These data indicate that oral administration of ivabradine in mice reduces HR while ventricular performance is maintained. This specific HR-reducing action of ivabradine is well preserved under conditions that are associated with significant activation of the sympathoadrenergic system.British Journal of Pharmacology (2004) 142, 107-112. doi:10.1038/sj.bjp.0705696 [ABSTRACT FROM AUTHOR]

The ribosomal DNA transcription-specific factor, UBF, is a key target for the regulation of ribosomal RNA synthesis and hypertrophic growth of isolated neonatal cardiomyocytes. In this study, we have examined whether UBF expression is also an important determinant of cardiac growth rates in vivo. We show that rDNA transcription, rRNA synthesis and UBF expression in left ventricular myocytes isolated from mice 1–6 weeks following transverse aortic constriction were significantly increased (2.5–3.5-fold) compared to the levels in myocytes from the left ventricle of sham-operated mice. [Copyright &y& Elsevier]

Transgenic (TG) mice with cardiac specific 200-fold overexpression of beta(2)-adrenoceptors (beta(2)-AR) have a facilitated development of heart failure following thoracic aortic constriction (TAC). We have studied the alterations of intracellular Ca(2+) transients and myocyte size in wild-type (WT) and TG mice after TAC. Cardiomyocytes were isolated from mice 9 weeks after TAC or sham operation, and incubated with Fura 2/AM. The Ca(2+) transients were determined by Spex dual wavelength Spectrometer during electrical stimulation. The cell size was also determined planimetrically. Cells of sham operated TG mice displayed higher systolic Ca(2+) amplitude than respective WT group (DeltaF(340)/F(380) ratio: 1.05+/-0.08 vs. 0.63+/-0.05; P<0.01), a finding in keeping with enhanced ventricular contractility in the TG mice. However, hypertrophied and failing myocytes of TG animals showed a fall in Ca(2+) transients from sham-operated control levels and there was no difference between TG and WT groups following TAC. In sham-operated groups, the cell size of TG mice was significantly bigger than in WT animals (3212+/-139 vs. 2605+/-162 microm(2); P<0.05). The cell size increased to a similar extent in both groups after TAC (4715+/-216 vs. 5027+/-365 microm(2), P=n.s.). In summary, hypertrophy of cardiomyocytes was present in beta(2)-AR TG mice under baseline conditions. A further hypertrophy occurred during pressure overload to an extent similar to that in WT animals. However, the increased intracellular Ca(2+) transient, seen in sham-operated TG mice, was no longer detectable following development of severe hypertrophy and heart failure. These findings provide explanation on the lack of hemodynamic benefit in beta(2)-AR TG mice subjected to pressure overload. [ABSTRACT FROM AUTHOR]

Transgenic (TG) mice with cardiac specific 200-fold overexpression of β2-adrenoceptors (β2-AR) have a facilitated development of heart failure following thoracic aortic constriction (TAC). We have studied the alterations of intracellular Ca2+ transients and myocyte size in wild-type (WT) and TG mice after TAC. Cardiomyocytes were isolated from mice 9 weeks after TAC or sham operation, and incubated with Fura 2/AM. The Ca2+ transients were determined by Spex dual wavelength Spectrometer during electrical stimulation. The cell size was also determined planimetrically. Cells of sham operated TG mice displayed higher systolic Ca2+ amplitude than respective WT group (ΔF340/F380 ratio: 1.05±0.08 vs. 0.63±0.05; P<0.01), a finding in keeping with enhanced ventricular contractility in the TG mice. However, hypertrophied and failing myocytes of TG animals showed a fall in Ca2+ transients from sham-operated control levels and there was no difference between TG and WT groups following TAC. In sham-operated groups, the cell size of TG mice was significantly bigger than in WT animals (3212±139 vs. 2605±162 μm2; P<0.05). The cell size increased to a similar extent in both groups after TAC (4715±216 vs. 5027±365 μm2, P=n.s.). In summary, hypertrophy of cardiomyocytes was present in β2-AR TG mice under baseline conditions. A further hypertrophy occurred during pressure overload to an extent similar to that in WT animals. However, the increased intracellular Ca2+ transient, seen in sham-operated TG mice, was no longer detectable following development of severe hypertrophy and heart failure. These findings provide explanation on the lack of hemodynamic benefit in β2-AR TG mice subjected to pressure overload. [Copyright &y& Elsevier]

SUMMARY 1. The aims of the present study were to characterize cardiac output (CO) in transgenic mice that overexpress the β2-adrenoceptor and to evaluate ultrasonic flowmetery for continuous CO measurement in the mouse in vivo. 2. Under conditions of anaesthesia, open chest and positive ventilation, CO was determined with a transonic flowmeter at baseline and during dobutamine administration and intravenous volume loading in wild-type mice (n = 17) and β2-adrenoceptor transgenic (n = 9) and wild-type mice with chronic myocardial infarct (n = 16). 3. Compared with wild-type mice, β2-adrenoceptor transgenic mice with markedly enhanced ventricular contractility had a significantly higher CO, heart rate (HR) and maximal acceleration of aortic flow. Both dobutamine and volume loading increased CO in the two groups and higher levels of CO were measured in transgenic mice during the interventions. At baseline or during interventions, stroke volume was similar between β2-adrenoceptor transgenic and wild-type mice. Infarcted mice with impaired cardiac function had a significantly lower CO under basal and stress conditions. 4. Thus, β2-adrenoceptor transgenic mice revealed higher CO that was largely attributable to a significantly higher HR but not to an increase in stroke volume. Transonic flowmetery can detect differences in CO among mice in various functional states and is suitable for evaluation of cardiac functional reserve in mice in vivo by continuous monitoring of CO responses to different interventions. [ABSTRACT FROM AUTHOR]

Summary It is known that T-cell vaccination (TCV) elicits cellular immune responses against the immunizing T cells in vivo . However, it is still unclear whether similar anti-T-cell responses are also induced in individuals responding to foreign antigen (Ag) challenge. This study was undertaken to characterize and compare anti-T-cell cellular and humoral responses of BALB/c mice after ovalbumin (OVA) immunization or TCV. Splenocytes from OVA-primed BALB/c mice proliferated in response to stimulation with a syngeneic OVA-specific T-cell clone, OVA-T3, and secreted interferon-γ (IFN-γ) but not interleukin-4 (IL-4). Cytotoxic T-lymphocyte (CTL) activity against the T-cell clone was also observed. Serum samples from these animals discriminated between activated and resting murine T cells, as determined by indirect immunofluorescence staining. Vaccination of BALB/c mice with OVA-T3 cells induced similar, but stronger, cellular and humoral responses. TCV-induced antibodies were not only able to distinguish between activated and resting syngeneic T cells but also positively stained allogeneic T cells from BXSB mice. Furthermore, TCV resulted in hyporesponsiveness of BALB/c mice to subsequent Ag challenge, and antisera from the immunized animals inhibited T-cell proliferation in vitro . Our data suggest that anti-T-cell antibodies, and CD4+ and CD8+ regulatory T lymphocytes may form a complex and co-ordinated regulatory network that plays an important role in regulating the adaptive immune responses in vivo . Implications of this observation for our understanding of the immunoregulation and peripheral tolerance are discussed. [ABSTRACT FROM AUTHOR]

Background: Early diagnosis and knowledge of infarct size is critical for the management of acute myocardial infarction (MI). We evaluated whether early elevated plasma level of macrophage migration inhibitory factor (MIF) is useful for these purposes in patients with ST-elevation MI (STEMI)., Methods and Results: We first studied MIF level in plasma and the myocardium in mice and determined infarct size. MI for 15 or 60 minutes resulted in 2.5-fold increase over control values in plasma MIF levels while MIF content in the ischemic myocardium reduced by 50% and plasma MIF levels correlated with myocardium-at-risk and infarct size at both time-points (P < 0.01). In patients with STEMI, we obtained admission plasma samples and measured MIF, conventional troponins (TnI, TnT), high sensitive TnI (hsTnI), creatine kinase (CK), CK-MB, and myoglobin. Infarct size was assessed by cardiac magnetic resonance (CMR) imaging. Patients with chronic stable angina and healthy volunteers were studied as controls. Of 374 STEMI patients, 68% had elevated admission MIF levels above the highest value in healthy controls (> 41.6 ng/mL), a proportion similar to hsTnI (75%) and TnI (50%), but greater than other biomarkers studied (20% to 31%, all P < 0.05 versus MIF). Only admission MIF levels correlated with CMR-derived infarct size, ventricular volumes and ejection fraction (n = 42, r = 0.46 to 0.77, all P < 0.01) at 3 day and 3 months post-MI., Conclusion: Plasma MIF levels are elevated in a high proportion of STEMI patients at the first obtainable sample and these levels are predictive of final infarct size and the extent of cardiac remodeling.

1. The traditional antegrade wire-guided percutaneous transcatheter approach is not ideal in closing some types of patent ductus arteriosus (PDA) with abnormal morphology. The aim of the present study was to evaluate the efficacy of a retrograde wire-guided transcatheter approach for closure of some types of PDA using the Amplatzer duct occluder (ADO). 2. Nineteen patients with abnormal PDA morphology, including a smaller ostium of the side of the pulmonary artery compared with the side of the descending aorta, severe calcification or tortuosity, were included in the present study. In these patients, after the antegrade approach failed to cross a wire from the pulmonary artery via the PDA to the descending aorta, a retrograde guidewire was passed through the PDA in the opposite direction, from the descending aorta to the pulmonary artery, to establish a femoral arteriovenous loop that assisted the deployment of the ADO in all 19 patients. The size of the PDA, as determined by angiography, was 3.1 +/- 1.1 mm and the diameter of the ADO selected was 6.5 +/- 1.5 mm. 3. In 16 cases, systolic murmur disappeared after the procedure. Systolic murmur (less than Grade II) and angiographic residual shunt remained in three cases immediately after the procedure, but disappeared 1 month later. Mean pulmonary arterial pressure decreased from 33 +/- 8 to 22 +/- 4 mmHg in all 19 patients (P < 0.01). There were no complications during or after the procedure. 4. The retrograde wire-guided technique offers an alternative approach to facilitate closure of a PDA that cannot be achieved by traditional antegrade wire-guided methods due to morphological abnormalities in the PDA.