Compensatory mechanisms of reduced interhemispheric EEG connectivity during sleep in patients with apnea

We performed a mathematical analysis of functional connectivity in electroencephalography (EEG) of patients with obstructive sleep apnea (OSA) (N = 10; age: 52.8 ± 13 years; median age: 49 years; male/female ratio: 7/3), compared with a group of apparently healthy participants (N = 15; age: 51.5 ± 29.5 years; median age: 42 years; male/female ratio: 8/7), based on the calculation of wavelet bicoherence from nighttime polysomnograms. Having observed the previously known phenomenon of interhemispheric synchronization deterioration, we demonstrated a compensatory increase in intrahemispheric connectivity, as well as a slight increase in the connectivity of the central and occipital areas for high-frequency EEG activity. Significant changes in functional connectivity were extremely stable in groups of apparently healthy participants and OSA patients, maintaining the overall pattern when comparing different recording nights and various sleep stages. The maximum variability of the connectivity was observed at fast oscillatory processes during REM sleep. The possibility of observing some changes in functional connectivity of brain activity in OSA patients in a state of passive wakefulness opens up prospects for further research. Developing the methods of hypnogram evaluation that are independent of functional connectivity may be useful for implementing a medical decision support system.

Heterologous chimpanzee adenovirus vector immunizations for SARS-CoV-2 spike and nucleocapsid protect hamsters against COVID-19

Available COVID-19 vaccine only provide protection for a limited time due in part to the rapid emergence of viral variants with spike protein mutations, necessitating the generation of new vaccines to combat SARS-CoV-2. Two serologically distinct replication-defective chimpanzee-origin adenovirus (Ad) vectors (AdC) called AdC6 and AdC7 expressing early SARS-CoV-2 isolate spike (S) or nucleocapsid (N) proteins, the latter expressed as a fusion protein within herpes simplex virus glycoprotein D (gD), were tested individually or as a mixture in a hamster COVID-19 SARS-CoV-2 challenge model. The S protein expressing AdC (AdC-S) vectors induced antibodies including those with neutralizing activity that in part cross-reacted with viral variants. Hamsters vaccinated with the AdC-S vectors were protected against serious disease and showed accelerated recovery upon SARS-CoV-2 challenge. Protection was enhanced if AdC-S vectors were given together with the AdC vaccines that expressed the gD N fusion protein (AdC-gDN). In contrast hamsters that just received the AdC-gDN vaccines showed only marginal lessening of symptoms compared to control animals. These results indicate that immune response to the N protein that is less variable than the S protein may potentiate and prolong protection achieved by the currently used S protein based genetic COVID-19 vaccines.

The effect of rapamycin and ibrutinib on antibody responses to adeno-associated virus vector-mediated gene transfer

Adeno-associated virus (AAV) vector-mediated gene transfer is lessening the impact of monogenetic disorders. Human AAV gene therapy recipients commonly mount immune responses to AAV or the encoded therapeutic protein, which requires transient immunosuppression. Most efforts to date have focused on blunting AAV capsid-specific T cell responses, which have been implicated in elimination of AAV transduced cells. Here we explore the use of immunosuppressants, rapamycin given alone or in combination with ibrutinib to inhibit AAV vector- or transgene product-specific antibody responses. Our results show that rapamycin or ibrutinib given alone reduce primary antibody responses against AAV capsid but the combination of rapamycin and ibrutinib is more effective, blunts recall responses, and reduces numbers of circulating antibody-secreting plasma cells. The drugs fail to lower B cell memory formation or to reduce the inhibitory effects of pre-existing AAV capsid-specific antibodies on transduction efficiency.

Stannyl radical-mediated synthesis of 6H-1,3-oxazin-6-ones from 2-acyloxyazirines or whether free radicals can open the azirine ring?

A fundamentally new radical cascade reaction of 2-acyloxyazirines underlays an effective one-step method for the preparation of 5-hydroxy-6H-1,3-oxazin-6-ones from methyl 2-acyloxy-2H-azirine-2-carboxylates using Bu3SnH/ACHN system as a source of stannyl radicals....

Hepatitis B virus polymerase-specific T cell epitopes shift in a mouse model of chronic infection

BACKGROUND

Chronic hepatitis B virus (HBV) infection (CHB) is a significant public health problem that could benefit from treatment with immunomodulators. Here we describe a set of therapeutic HBV vaccines that target the internal viral proteins.

METHODS

Vaccines are delivered by chimpanzee adenovirus vectors (AdC) of serotype 6 (AdC6) and 7 (AdC7) used in prime only or prime-boost regimens. The HBV antigens are fused into an early T cell checkpoint inhibitor, herpes simplex virus (HSV) glycoprotein D (gD), which enhances and broadens vaccine-induced cluster of differentiation (CD8)⁺ T cell responses.

RESULTS

Our results show that the vaccines are immunogenic in mice. They induce potent CD8⁺ T cell responses that recognize multiple epitopes. CD8⁺ T cell responses increase after a boost, although the breadth remains similar. In mice, which carry high sustained loads of HBV particles due to a hepatic infection with an adeno-associated virus (AAV)8 vector expressing the 1.3HBV genome, CD8⁺ T cell responses to the vaccines are attenuated with a marked shift in the CD8⁺ T cells' epitope recognition profile.

CONCLUSIONS

Our data show that in different stains of mice including those that carry a human major histocompatibility complex (MHC) class I antigen HBV vaccines adjuvanted with a checkpoint inhibitor induce potent and broad HBV-specific CD8⁺ T cell responses and lower but still detectable CD4⁺ T cell responses. CD8⁺ T cell responses are reduced and their epitope specificity changes in mice that are chronically exposed to HBV antigens. Implications for the design of therapeutic HBV vaccines are discussed.

T cell responses to adenoviral vectors expressing the SARS-CoV-2 nucleoprotein

SARS-CoV-2 vaccines aim to protect against COVID-19 through neutralizing antibodies against the viral spike protein. Mutations within the spike's receptor-binding domain may eventually reduce vaccine efficacy, necessitating periodic updates. Vaccine-induced immunity could be broadened by adding T cell-inducing antigens such as SARS-CoV-2's nucleoprotein (N). Here we describe two replication-defective chimpanzee adenovirus (AdC) vectors from different serotypes expressing SARS-CoV-2 N either in its wild-type form or fused into herpes simplex virus glycoprotein D (gD), an inhibitor of an early T cell checkpoint. The vaccines induce potent and sustained CD8⁺ T cell responses that are broadened upon inclusion of gD. Depending on the vaccine regimen booster immunizations increase magnitude and breadth of T cell responses. Epitopes that are recognized by the vaccine-induced T cells are highly conserved among global SARS-CoV-2 isolates indicating that addition of N to COVID-19 vaccines may lessen the risk of loss of vaccine-induced protection due to variants.

Intraoperative transesophageal assessment of coronary artery flow can predict 5 type myocardial infarction

Background

Stenosis of a coronary artery results in an increase in flow velocity in the pathologic segment. Effective grafting should decrease the stenotic native coronary velocity according to hemodynamic law. The range of decreased velocity before and after cardiac surgery can hypothetically reflect the effectiveness of a graft. The aim of the study is to determine if measuring coronary flow velocity changes during coronary artery bypass grafting (CABG) can predict intraoperative myocardial infarction.

Methods

One hundred sixty-six (166) consecutive patients (121 men, 64±9 years old) referred for cardiac surgery, were prospectively included in the study. A standard basic perioperative transesophageal echocardiography (TEE) examination was performed with additional scans of the left main, left anterior descending (LAD), and circumflex (LCx) arteries' proximal segments. Measurements of coronary flow velocities were performed before and after grafting in the same sites of the arteries. The maximal value of cardiac troponin I (cTnI) after CABG and the additive criteria were accounted for in the analysis as it is described in the expert consensus document for Type 5 myocardial infarction (MI) definition.

Results

One hundred sixty-three patients (98%) had arterial hypertension, 28 patients (17%) had diabetes mellitus, 35 patients (21%) were currently smokers. The feasibility of coronary flow assessment during cardiac operations was 95%. Before grafting, the mean velocity in the left main artery was 91±49 cm/s, in LAD 101±35 cm/s, and in LCx 117±49 cm/s.

There was a significant correlation between changes in coronary flow velocities during operation and the value of cTnI (R=0.34, p<0.0001). Ten patients met the criteria for Type 5 MI. There were no differences in age, body mass index, number of coronary arteries with stenoses, frequency of prior MI, ejection fraction or coronary flow velocity before surgery in patients with and without Type 5 MI. The group of patients with Type 5 MI had an increase in native artery velocities during surgery in comparison with patients without MI, who had a significant decrease in coronary flow velocity after grafting (30±48 vs. −10±30 cm/s; p<0.0006). Increases in native coronary velocities greater than 3 cm/s predicted Type 5 MI with 81% accuracy (sensitivity 88%, specificity 70%).

Conclusion

Coronary flow velocity assessment during cardiac surgery could predict an elevation of cardiac troponins and Type 5 MI.

Funding Acknowledgement

Type of funding source: None

P1564 Changes in coronary flow velocity measuring during coronary bypass grafting can predict elevation of cardiac troponin

Background

Stenosis of a coronary artery results in an increase in flow velocity in the pathologic segment. Effective grafting should decrease the stenotic native coronary velocity according to a hemodynamic law. The range of decreased velocity can hypothetically reflect the effectiveness of a graft. Grafting effect insufficiencies often cause elevations in periprocedural cardiac troponin (cTn) elevation. The aim of the study is to determine, if measuring coronary flow velocity changes during coronary artery bypass grafting (CABG) can predict further cTn elevation.

Methods and results

Consecutive 68 patients (48 men, 64 ± 9 years old), who were referred for CABG, were included into the study. A standard basic perioperative transesophageal echocardiography (TEE) examination was performed with additional scans of the left main, left anterior descending (LAD), and circumflex (LCx) arteries’ proximal segments. Measurements of coronary flow velocities was performed before and after grafting in the same sites of the arteries. The maximal value of cTnI within 48 hours after CABG was accounted for in the analysis. All patients had arterial hypertension, 15 patients (22%) had diabetes mellitus, 12 patients (18%) was current smokers. Forty-one patients (60%) had prior myocardial infarctions, 18 persons (26%) had previous coronary stenting. The ejection fraction before the operation was 56 ± 13%. Before grafting the mean velocity in the left main artery was 79 cm/s (25th-75th quartile, 42-111), in LAD 98 cm/s (25th-75th quartile, 71-125), and in LCx 116 cm/s (25th-75th quartile, 68-156).

There was a strong significant correlation between changes in coronary flow velocities and the value of cTnI (R = 0.56, p < 0.0004). The patients with and without significant elevations in cTnI had differences in coronary velocity changes before and after grafting (p < 0.009). Patients with elevated cTnI in more than 5 times, had, on average, an increase in the velocities for native arteries of 21 ± 19 cm/s.

Conclusion

Coronary flow velocity assessment during CABG could predict an elevation of cardiac troponins after cardiac surgery.

Abstract P1564 Figure.

An Azirine Strategy for the Synthesis of Alkyl 4-Amino-5-(trifluoromethyl)-1H-pyrrole-2-carboxylates

1-(3,3,3-Trifluoro-2,2-dihydroxypropyl)pyridin-1-ium bromide serves as a trifluoromethyl-containing building block for the preparation of trifluoromethyl-substituted aminopyrroles based on the 2H-azirine ring expansion strategy. The primary products, 3-aryl-2-(methoxycarbonyl)-4-(pyridin-1-ium-1-yl)-5-(trifluoromethyl)pyrrol-1-ides, can be hydrogenated by H2/PtO2 to form alkyl 3-aryl-4-(piperidin-1-yl)-5-(trifluoromethyl)-1H-pyrrole-2-carboxylates and transformed into alkyl 4-amino-3-aryl-1-methyl-5-(trifluoromethyl)-1H-pyrrole-2-carboxylates via methylation/hydrazinolysis.

Synthesis of Substituted Indole-3-carboxylates by Iron(II)-Catalyzed Domino Isomerization of 3-Alkyl/aryl-4-aryl-5-methoxyisoxazoles

The iron(II)-catalyzed domino isomerization of 3-alkyl/aryl-4-arylisoxazoles provides a selective access to a wide range of structurally diverse highly substituted indole-3-carboxylates. The operational simplicity, high atom efficiency, and the use of stable starting materials and an inexpensive and low-toxicity catalyst are some of the attractive features of this tandem double ring-opening–ring-closure strategy.

Optimization of the Synthesis of Superhydrophobic Carbon Nanomaterials by Chemical Vapor Deposition

Demand is increasing for superhydrophobic materials in many applications, such as membrane distillation, separation and special coating technologies. In this study, we report a chemical vapor deposition (CVD) process to fabricate superhydrophobic carbon nanomaterials (CNM) on nickel (Ni)-doped powder activated carbon (PAC). The reaction temperature, reaction time and H₂/C₂H₂ gas ratio were optimized to achieve the optimum contact angle (CA) and carbon yield (CY). For the highest CY (380%) and CA (177°), the optimal reaction temperatures were 702 °C and 687 °C, respectively. However, both the reaction time (40 min) and gas ratio (1.0) were found to have similar effects on CY and CA. Based on the Field emission scanning electron microscopy and transmission electron microscopy images, the CNM could be categorized into two main groups: a) carbon spheres (CS) free carbon nanofibers (CNFs) and b) CS mixed with CNFs, which were formed at 650 and 750 °C, respectively. Raman spectroscopy and thermogravimetric analysis also support this finding. The hydrophobicity of the CNM, expressed by the CA, follows the trend of CS-mixed CNFs (CA: 177°) > CS-free CNFs (CA: 167°) > PAC/Ni (CA: 65°). This paves the way for future applications of synthesized CNM to fabricate water-repellent industrial-grade technologies.

Metal-Catalyzed Isomerization of 5-Heteroatom-Substituted Isoxazoles­ as a New Route to 2-Halo-2H-azirines

A convenient gram-scale method for the preparation of 2-halo-2H-azirine-2-carboxylic acid esters, thioesters and amides via metal-catalyzed isomerization of 5-heteroatom-substituted 4-haloisoxazoles is developed. The formation of the esters and amides is efficiently catalyzed by Rh2(Piv)4, while FeCl2·4H2O is the catalyst of choice for the synthesis of the thioesters. In addition, rhodium catalysis is successfully applied in the synthesis of azirine-2-carboxylates from non-halogenated 5-alkoxyisoxazoles.

Temperature dependence of electro-optic effect and natural linear birefringence in quartz measured by low-coherence interferometry

Temperature dependencies of the half-wave voltage and natural linear birefringence in mechanically free quartz are measured at 1560 nm in the temperature range of 85-310 K. Measurements are carried out using a low-coherence interferometric scheme with a pair of identical quartz crystals independently linked with a scanning Michelson interferometer. Half-wave voltage V11 driven by an electro-optic coefficient r11 grows from 868 kV at 85 K to 923 kV at 310 K. The temperature derivative of natural linear birefringence Δn has nearly linear temperature dependence: ∂Δn/∂T=-7.260×10(-7)-9.93×10(-10)  T K(-1). Moderate temperature dependence of the electro-optic effect, along with other properties, makes quartz an appropriate sensing medium for electro-optic voltage sensors for the electric power industry.

5-Arylaminouracil Derivatives: New Inhibitors of Mycobacterium tuberculosis

Three series of 5-arylaminouracil derivatives, including 5-(phenylamino)uracils, 1-(4'-hydroxy-2'-cyclopenten-1'-yl)-5-(phenylamino)uracils, and 1,3-di-(4'-hydroxy-2'-cyclopenten-1'-yl)-5-(phenylamino)uracils, were synthesized and screened for potential antimicrobial activity. Most of compounds had a negative effect on the growth of the Mycobacterium tuberculosis H37Rv strain, with 100% inhibition observed at concentrations between 5 and 40 μg/mL. Of those, 1-(4'-hydroxy-2'-cyclopenten-1'-yl)-3-(4‴-hydroxy-2‴-cyclopenten-1‴-yl)-5-(4″-butyloxyphenylamino)uracil proved to be the most active among tested compounds against the M. tuberculosis multidrug-resistant strain MS-115 (MIC90 5 μg/mL). In addition, the thymidylate kinase of M. tuberculosis was evaluated as a possible enzymatic target.

Impact of field strength and iron oxide nanoparticle concentration on the linearity and diagnostic accuracy of off-resonance imaging

Off-resonance imaging (ORI) techniques are being increasingly used to image iron oxide imaging agents such as monocrystalline iron oxide nanoparticles (MION). However, the diagnostic accuracy, linearity, and field dependence of ORI have not been fully characterized. In this study, the sensitivity, specificity, and linearity of ORI were thus examined as a function of both MION concentration and magnetic field strength (4.7 and 14 T). MION phantoms with and without an air interface as well as MION uptake in a mouse model of healing myocardial infarction were imaged. MION-induced resonance shifts were shown to increase linearly with MION concentration. In contrast, the ORI signal/sensitivity was highly non-linear, initially increasing with MION concentration until T2 became comparable to the TE and decreasing thereafter. The specificity of ORI to distinguish MION-induced resonance shifts from on-resonance water was found to decrease with increasing field because of the increased on-resonance water linewidths (15 Hz at 4.7 T versus 45 Hz at 14 T). Large resonance shifts ( approximately 300 Hz) were observed at air interfaces at 4.7 T, both in vitro and in vivo, and led to poor ORI specificity for MION concentrations less than 150 microg Fe/mL. The in vivo ORI sensitivity was sufficient to detect the accumulation of MION in macrophages infiltrating healing myocardial infarcts, but the specificity was limited by non-specific areas of positive contrast at the air/tissue interfaces of the thoracic wall and the descending aorta. Improved specificity and linearity can, however, be expected at lower fields where decreased on-resonance water linewidths, reduced air-induced resonance shifts, and longer T2 relaxation times are observed. The optimal performance of ORI will thus likely be seen at low fields, with moderate MION concentrations and with sequences containing very short TEs.

Fluorescence tomography and magnetic resonance imaging of myocardial macrophage infiltration in infarcted myocardium in vivo

BACKGROUND

Fluorescence imaging of the heart is currently limited to invasive ex vivo or in vitro applications. We hypothesized that the adaptation of advanced transillumination and tomographic techniques would allow noninvasive fluorescence images of the heart to be acquired in vivo and be coregistered with in vivo cardiac magnetic resonance images.

METHODS AND RESULTS

The uptake of the magnetofluorescent nanoparticle CLIO-Cy5.5 by macrophages in infarcted myocardium was studied. Ligation of the left coronary artery was performed in 12 mice and sham surgery in 7. The mice were injected, 48 hours after surgery, with 3 to 20 mg of iron per kilogram of CLIO-Cy5.5. Magnetic resonance imaging and fluorescence molecular tomography were performed 48 hours later. An increase in magnetic resonance imaging contrast-to-noise ratio, indicative of myocardial probe accumulation, was seen in the anterolateral walls of the infarcted mice but not in the sham-operated mice (23.0+/-2.7 versus 5.43+/-2.4; P<0.01). Fluorescence intensity over the heart was also significantly greater in the fluorescence molecular tomography images of the infarcted mice (19.1+/-5.2 versus 5.3+/-1.4; P<0.05). The uptake of CLIO-Cy5.5 by macrophages infiltrating the infarcted myocardium was confirmed by fluorescence microscopy and immunohistochemistry.

CONCLUSIONS

Noninvasive imaging of myocardial macrophage infiltration has been shown to be possible by both fluorescence tomography and magnetic resonance imaging. This could be of significant value in both the research and clinical settings. The techniques developed could also be used to image other existing fluorescent and magnetofluorescent probes and could significantly expand the role of fluorescence imaging in the heart.

Transverse aortic constriction leads to accelerated heart failure in mice lacking PPAR-gamma coactivator 1alpha

Heart failure is accompanied by important defects in metabolism. The transcriptional coactivator peroxisome proliferator-activated receptor-gamma coactivator 1alpha (PGC-1alpha) is a powerful regulator of mitochondrial biology and metabolism. PGC-1alpha and numerous genes regulated by PGC-1alpha are repressed in models of cardiac stress, such as that generated by transverse aortic constriction (TAC). This finding has suggested that PGC-1alpha repression may contribute to the maladaptive response of the heart to chronic hemodynamic loads. We show here that TAC in mice genetically engineered to lack PGC-1alpha leads to accelerated cardiac dysfunction, which is accompanied by signs of significant clinical heart failure. Treating cardiac cells in tissue culture with the catecholamine epinephrine leads to repression of PGC-1alpha and many of its target genes, recapitulating the findings in vivo in response to TAC. Importantly, introduction of ectopic PGC-1alpha can reverse the repression of most of these genes by epinephrine. Together, these data indicate that endogenous PGC-1alpha serves a cardioprotective function and suggest that repression of PGC-1alpha significantly contributes to the development of heart failure. Moreover, the data suggest that elevating PGC-1alpha activity may have therapeutic potential in the treatment of heart failure.

Myostatin regulates cardiomyocyte growth through modulation of Akt signaling

Myostatin is a highly conserved, potent negative regulator of skeletal muscle hypertrophy in many species, from rodents to humans, although its mechanisms of action are incompletely understood. Transcript profiling of hearts from a genetic model of cardiac hypertrophy revealed dramatic upregulation of myostatin, not previously recognized to play a role in the heart. Here we show that myostatin abrogates the cardiomyocyte growth response to phenylephrine in vitro through inhibition of p38 and the serine-threonine kinase Akt, a critical determinant of cell size in many species from drosophila to mammals. Evaluation of male myostatin-null mice revealed that their cardiomyocytes and hearts overall were slightly smaller at baseline than littermate controls but exhibited more exuberant growth in response to chronic phenylephrine infusion. The increased cardiac growth in myostatin-null mice corresponded with increased p38 phosphorylation and Akt activation in vivo after phenylephrine treatment. Together, these data demonstrate that myostatin is dynamically regulated in the heart and acts more broadly than previously appreciated to regulate growth of multiple types of striated muscle.

Factor XIII deficiency causes cardiac rupture, impairs wound healing, and aggravates cardiac remodeling in mice with myocardial infarction

BACKGROUND

Identification of key molecular players in myocardial healing could lead to improved therapies, reduction of scar formation, and heart failure after myocardial infarction (MI). We hypothesized that clotting factor XIII (FXIII), a transglutaminase involved in wound healing, may play an important role in MI given prior clinical and mouse model data.

METHODS AND RESULTS

To determine whether a truly causative relationship existed between FXIII activity and myocardial healing, we prospectively studied myocardial repair in FXIII-deficient mice. All FXIII(-/-) and FXIII(-)(/+) (FXIII activity <5% and 70%) mice died within 5 days after MI from left ventricular rupture. In contradistinction, FXIII(-/-) mice that received 5 days of intravenous FXIII replacement therapy had normal survival rates; however, cardiac MRI demonstrated worse left ventricular remodeling in these reconstituted FXIII(-/-) mice. Using a FXIII-sensitive molecular imaging agent, we found significantly greater FXIII activity in wild-type mice and FXIII(-/-) mice receiving supplemental FXIII than in FXIII(-/-) mice (P<0.05). In FXIII(-/-) but not in reconstituted FXIII(-/-) mice, histology revealed diminished neutrophil migration into the MI. Reverse transcriptase-polymerase chain reaction studies suggested that the impaired inflammatory response in FXIII(-/-) mice was independent of intercellular adhesion molecule and lipopolysaccharide-induced CXC chemokine, both important for cell migration. After MI, expression of matrix metalloproteinase-9 was 650% higher and collagen-1 was 53% lower in FXIII(-/-) mice, establishing an imbalance in extracellular matrix turnover and providing a possible mechanism for the observed cardiac rupture in the FXIII(-/-) mice.

CONCLUSIONS

These data suggest that FXIII has an important role in murine myocardial healing after infarction.

Serum and Glucocorticoid-Responsive Kinase-1 Regulates Cardiomyocyte Survival and Hypertrophic Response

Background— Serum- and glucocorticoid-responsive kinase-1 (SGK1), a serine-threonine kinase that is highly expressed in the heart, has been previously reported to regulate sodium channels. Because SGK1 is a PI 3-kinase–dependent kinase with structural homology to Akt, we examined its regulation in the heart and its effects on cardiomyocyte (CM) apoptosis and hypertrophy in vitro.

Methods and Results— Rats were subjected to aortic banding, and expression of total and phosphorylated SGK1 was examined. Both phospho- and total SGK1 increased 2 to 7 days after banding. Phospho-SGK1 was also upregulated in CMs stimulated in vitro with IGF-I or phenylephrine. Infection of CMs with an adenoviral vector encoding constitutively active SGK1 (Ad.SGK1.CA) inhibited apoptosis after serum-deprivation or hypoxia ( P <0.05), whereas expression of kinase-dead SGK1 (Ad.SGK1.KD) increased it and partially mitigated the protective effects of IGF-I ( P <0.05). SGK1 activation was also sufficient to increase cell size, protein synthesis, sarcomere organization, and ANF expression both at baseline and in response to phenylephrine but was not necessary for the hypertrophic response to phenylephrine. Evaluation of potential downstream signaling pathways demonstrated that SGK1 induces phosphorylation of tuberin, p70s6kinase, and GSK3β in CMs, which may contribute to its effects.

Conclusions— SGK1 is dynamically regulated during acute biomechanical stress in the heart and inhibits CM apoptosis while enhancing the hypertrophic response.

Lipopolysaccharide improves cardiomyocyte survival and function after serum deprivation

Toll-like receptor-4 (TLR4) and its signaling molecule interleukin-1 receptor-associated kinase (IRAK-1) play an important role in host defense and tissue inflammation. Intriguingly, systemic administration of lipopolysaccharide (LPS), the agonist for TLR4, confers a cardio-protective effect against ischemic injury. However, the mechanisms leading to the cardiac protection remain largely unknown. The present study was designed to investigate the role of TLR4 activation by LPS in protecting cardiomyocytes (CM) against apoptosis in an in vitro model of ischemia and to explore the downstream mechanisms leading to the protective effect. Incubation with LPS led to activation of IRAK-1 and protected CMs against serum deprivation (SD)-induced apoptosis as demonstrated by DNA laddering, histone-DNA fragment enzyme-linked immunosorbent assay, and activation of caspase-3. Phosphatidylinositol 3-kinase/Akt, extracellular signal-regulated kinase 1/2, and IkappaB kinase beta appear to contribute to the anti-apoptotic effect of LPS since the specific inhibitors, wortmannin, PD98059, and dominant negative IKKbeta transgene expression reversed the LPS effect. To assess whether LPS improves CM function, we examined intracellular Ca(2+) transients and cell shortening in single adult rat CMs. SD for 6 h dramatically inhibited Ca(2+) transients and CM contractility. LPS at 500 ng/ml significantly improved the [Ca(2+)](i) transients and enhanced contractility in control CMs as well as in CMs subjected to SD. Importantly, transient ischemia led to rapid activation of IRAK-1 in cultured CMs and in adult rat myocardium. Adenovirus-mediated transgene expression of IRAK-1 but not its kinase-deficient mutant IRAK-1(K239S) protected CMs against SD-induced apoptosis. Taken together, these data suggest an important role of TLR4 signaling via IRAK-1 in protecting against SD-induced apoptosis.

[A methodological study in a space flight simulation context]

To study the effects of isolation and confinement on small groups during long space flights, it is habitual to use closed hyperbaric ground chambers. For the first time, the European Space Agency made use of a nautral environment taking advantage of an Antarctic winter-over at the French Dumont d'Urville Station. The main objective of that study ("International Antarctic Psychological Programme"), was to compare different Russian tests used for training cosmonauts to a W. European approach validated during previous winter studies and European ground chamber simulations. Russian techniques appeared to be oriented to a narrow range of phenomena and unsuited to discern the adjustment to stress conditions.

The significance of persistent ST elevation versus early resolution of ST segment elevation after primary PTCA

OBJECTIVES

To determine the prevalence and clinical significance of early ST segment elevation resolution after primary percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction (AMI).

BACKGROUND

Despite angiographically successful restoration of coronary flow early during AMI, adequate myocardial reperfusion might not occur in a substantial portion of the jeopardized myocardium due to microvascular damage. This phenomenon comprises the potentially beneficial effect of early recanalization of the infarct related artery (IRA).

METHODS

Included in the study were 117 consecutive patients who underwent angiographically successful [Thrombolysis in Myocardial Infarction (TIMI III)] primary PTCA. The patients were classified based on the presence or absence of reduction > or =50% in ST segment elevation in an ECG performed immediately upon return to the intensive cardiac care unit after the PTCA in comparison with ECG before the intervention.

RESULTS

Eighty-nine patients (76%) had early ST segment elevation resolution (Group A) and 28 patients (24%) did not (Group B). Group A and B had similar clinical and hemodynamic features before referring to primary PTCA, as well as similar angiographic results. Despite this, ST segment elevation resolution was associated with better predischarge left ventricular ejection fraction (LVEF) (44.7 +/- 8.0 vs. 38.2 +/- 8.5, p < 0.01). Group B patients, as compared with those of Group A, had a higher incidence of in-hospital mortality (11% vs. 2%, p = 0.088), congestive heart failure (CHF) [28% vs. 19%, odds ratio (OR) = 4, 95% confidence interval (CI) 1 to 15, p = 0.04], higher long-term mortality (OR = 7.3, 95% CI 1.9 to 28, p = 0.004 with Cox proportional hazard regression analysis) and long-term CHF rate (OR = 6.5, 95% CI 1.3 to 33, p = 0.016 with logistic regression).

CONCLUSIONS

Absence of early ST segment elevation resolution after angiographically successful primary PTCA identifies patients who are less likely to benefit from the early restoration of flow in the IRA, probably because of microvascular damage and subsequently less myocardial salvage.

Long-term effect of HU-211, a novel non-competitive NMDA antagonist, on motor and memory functions after closed head injury in the rat

HU-211 is a synthetic, non-psychotropic cannabinoid which acts as a non-competitive NMDA antagonist and antioxidant. We studied the drug's therapeutic window as well as its long-term effect on cognitive and motor functions in a model of closed head injury (CHI) in the rat. A weight-drop device was used to induce CHI in either anesthetized male rats. HU-211 (5 mg/kg) was administered i.v. to the experimental groups. For the therapeutic window study, drug was injected at 4 or 6 h after CHI. Edema (water content) and clinical status (neurological severity score, NSS) were evaluated at 24 h. Reduction of edema was slight, whereas improvement of NSS was significant when the drug was administered at 4 or 6 h (P = 0.0023 and 0.059, respectively). To determine the drug's long-term effect, it was administered 1 h after CHI and additional doses were later given. NSS was evaluated for a period of 30 d. A single dose of HU-211 given 1 h post-CHI improved the clinical outcome during the 30 d period (P < 0.01). Repetitive doses of HU-211 injected during the post traumatic period had similar effects. Cognitive functions were evaluated in the Morris water maze, with rats trained either before or after CHI. CHI resulted in a highly significant impairment of these abilities, whereas HU-211 treatment 1 h after CHI improved performance. Our results indicate that HU-211 is a potent cerebroprotective agent, with a therapeutic window of about 4 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Closed head injury triggers early production of TNF alpha and IL-6 by brain tissue

In a model of closed head injury (CHI) in the rat we have shown the activation of phospholipase A2 and the production of eicosanoids after injury: at 15 min, mainly 5-hydroxyeicosatetraenoic acid (5-HETE), and at 24 h, mainly prostaglandin E2. The present study was designed to test whether CHI can also trigger the production of cytokines in the brain. CHI was induced in ether-anesthesized rats by a weight-drop device falling over the exposed skull covering the left hemisphere, 1-2 mm lateral to the midline in the midcoronal plane. In the posttraumatic period (1-24 h), the rats were decapitated, cortical tissue from the injured zone of the contused and contralateral hemispheres was removed and sonicated, and cytokine activity was assessed. Whereas no tumor necrosis factor alpha (TNF alpha) activity was found in normal brain tissue, it was detectable in the contused hemisphere (approximately of 72 +/- 50 pg/mg protein) as early as 1 h post-CHI. TNF alpha levels increased at 2 h, peaked at 4 h, (approximately of 609 +/- 540 pg/mg protein), and declined thereafter. At parallel intervals, only low levels of TNF alpha were detected in the contralateral hemisphere. In normal brain, interleukin-6 (IL-6) was nondetectable. Following CHI, high levels of IL-6 were present, although their accumulation lagged behind that of TNF alpha by 2-4 h, peaking at 8 h (62 +/- 31 ng/mg protein). We suggest that the rapid production of TNF alpha and IL-6 following CHI is a local inflammatory response of brain tissue to primary insult.

Long term exposure to heat reduces edema formation after closed head injury in the rat

Cerebral edema is one of the major consequences of head trauma (HT); its evolution may cause secondary ischemia and neuronal damage. In a closed head injury model in rats, we have shown BBB disruption and edema formation during the post traumatic period. We have previously shown that chronic exposure to moderate heat improves clinical outcome of rats subjected to HT. Long term exposure to heat results in the achievement of a stable acclimated state, characterized by a lower metabolic rate and improved heat tolerance. In the present study, we investigated the effect of chronic exposure to heat on edema formation after HT. Rats were held at 24 degrees C (CON) or 34 degrees C (ACC) for one month. Injury was then induced under ether anesthesia by a weight drop device. Four or 48 hours later, they were sacrificed for evaluation of BBB integrity (Evans blue, EB, extravasation) or edema formation (specific gravity, SG, or percent water). We found that EB uptake by the contused hemisphere was 6 fold lower in the ACC rats as compared to CON (p < 0.001). Furthermore, edema measured at 48 h by both SG and percent water methods was significantly lower in the acclimated rats (p < 0.01). We suggest that heat acclimation offers protection to rats subjected to head injury, possibly by reduction of plasma proteins extravasation.

A nonpsychotropic cannabinoid, HU-211, has cerebroprotective effects after closed head injury in the rat

HU-211 is a synthetic, nonpsychotropic cannabinoid, which has been shown to act as a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist. The cerebroprotective effects of this compound were assessed in a model of closed head injury in rats. Head trauma (HT) was induced in ether-anesthetized rats by a weight-drop device; recovery was followed up to 48 h. The clinical status of the rats was evaluated at 1, 24, and 48 h after injury, and the extent of edema formation was determined by specific gravity (SG) and water content measurements at 24 or 48 h. The integrity of the blood-brain barrier (BBB) was investigated using Evans-Blue extravasation at 4 h after HT. HU-211 at a dose of 25 mg/kg in middle-chain triglycerides (MCT) oil was given intraperitoneally immediately and 1, 2, or 3 h after impact, and its effect on the various parameters was studied. The drug was found to be very effective in improving motor function recovery. When the drug was given 1 h after HT, the percent of rats able to perform beam walking task on 8.5- and 5-cm wide beams was increased from 30% and 0% to 79% (p = 0.0172) and 57% (p = 0.0029), respectively. The percent of rats able to balance on a 1.5-cm beam for 20 and 40 sec was also significantly increased, from 9% and 0% to 72% (p = 0.0037) and 50% (p = 0.078), respectively. The drug was also effective in reducing the BBB breakdown by more than four fold, as compared with control (548 +/- 94 versus 128 +/- 19 ng Evans blue/g tissue; p < 0.05) and attenuating cerebral edema. SG was 1.0367 +/- 0.0007 versus 1.0399 +/- 0.0005, and percent water content was 83.06 +/- 0.57 versus 80.78 +/- 0.36 (p < 0.05) in control and HU-211 treated rats, respectively. Similar significant protection was found when the drug was injected 2 h after the injury; however, at 3 h the effect was somewhat less pronounced. We suggest that this novel drug is a potential cerebroprotector in head trauma with a therapeutic window of at least 2 to 3 h.