Multifunctional Effect of Fe Substitution in Na Layered Cathode Materials for Enhanced Storage Stability

Developing stable cathode materials that are resistant to storage degradation is essential for practical development and industrial processing of Na-ion batteries as many sodium layered oxide materials are susceptible to hygroscopicity and instability upon exposure to ambient air. Among the various layered compounds, Fe-substituted O3-type Na(Ni1/2Mn1/2)1-xFexO2 materials have emerged as a promising option for high-performance and low-cost cathodes. While previous reports have noted the decent air-storage stability of these materials, the role and origin of Fe substitution in improving storage stability remain unclear. In this study, we investigate the air-resistant effect of Fe substitution in O3-Na(Ni1/2Mn1/2)1-xFexO2 cathode materials by performing systematic surface and structural characterizations. We find that the improved storage stability can be attributed to the multifunctional effect of Fe substitution, which forms a surface protective layer containing an Fe-incorporated spinel phase and decreases the thermodynamical driving force for bulk chemical sodium extraction. With these mechanisms, Fe-containing cathodes can suppress the cascades of cathode degradation processes and better retain the electrochemical performance after air storage.

Structural, magnetic, and magnetocaloric properties of R2NiMnO6 (R = Eu, Gd, Tb)

The crystal structure, cryogenic magnetic properties, and magnetocaloric performance of double perovskite Eu₂NiMnO₆ (ENMO), Gd₂NiMnO₆ (GNMO), and Tb₂NiMnO₆ (TNMO) ceramic powder samples synthesized by solid-state method have been investigated. X-ray diffraction structural investigation reveal that all compounds crystallize in the monoclinic structure with a P2₁/n space group. A ferromagnetic to paramagnetic (FM-PM) second-order phase transition occurred in ENMO, GNMO, and TNMO at 143, 130, and 112 K, respectively. Maximum magnetic entropy changes and relative cooling power with a 5 T applied magnetic field are determined to be 3.2, 3.8, 3.5 J/kgK and 150, 182, 176 J/kg for the investigated samples, respectively. The change in structural, magnetic, and magnetocaloric effect attributed to the superexchange mechanism of Ni²⁺–O–Mn³⁺ and Ni²⁺–O–Mn⁴⁺. The various atomic sizes of Eu, Gd, and Tb affect the ratio of Mn⁴⁺/Mn³⁺, which is responsible for the considerable change in properties of double perovskite.

Process Engineering to Increase the Layered Phase Concentration in the Immediate Products of Flame Spray Pyrolysis

Flame-spray-pyrolysis (FSP) is a robust and scalable process to synthesize particles at the commodity-scale. FSP has been used to produce the precursor powders which were converted to the layered structure (R3̅m phase) by a postannealing step in making nickel-rich cathode materials (NCMs). Theoretically, the high flame temperature (normally >1500 K) in FSP can provide adequate energy for the phase conversion from rock-salt to layered structures and potentially enables one-step synthesis. However, the high flame temperature is a critical issue to cause lithium loss and structural degradation, preventing the formation of the layered phase. In this work, guided by the gaseous nucleation theory, we implemented several FSP processes with different solution recipes. The layered phase concentration in the as-burned products can be increased with the solution enthalpies. By adding a rapid quench step to suppress the lithium loss and phase degradation, the layered phase can be further increased. This work contributes new ideas to innovating process regarding the process efficiency and throughput of manufacturing cathode materials at a large scale.

Voltage decay and redox asymmetry mitigation by reversible cation migration in lithium-rich layered oxide electrodes

Despite the high energy density of lithium-rich layered-oxide electrodes, their real-world implementation in batteries is hindered by the substantial voltage decay on cycling. This voltage decay is widely accepted to mainly originate from progressive structural rearrangements involving irreversible transition-metal migration. As prevention of this spontaneous cation migration has proven difficult, a paradigm shift toward management of its reversibility is needed. Herein, we demonstrate that the reversibility of the cation migration of lithium-rich nickel manganese oxides can be remarkably improved by altering the oxygen stacking sequences in the layered structure and thereby dramatically reducing the voltage decay. The preeminent intra-cycle reversibility of the cation migration is experimentally visualized, and first-principles calculations reveal that an O2-type structure restricts the movements of transition metals within the Li layer, which effectively streamlines the returning migration path of the transition metals. Furthermore, we propose that the enhanced reversibility mitigates the asymmetry of the anionic redox in conventional lithium-rich electrodes, promoting the high-potential anionic reduction, thereby reducing the subsequent voltage hysteresis. Our findings demonstrate that regulating the reversibility of the cation migration is a practical strategy to reduce voltage decay and hysteresis in lithium-rich layered materials.

Gut Microbial Metabolites Induce Changes in Circadian Oscillation of Clock Gene Expression in the Mouse Embryonic Fibroblasts

Circadian rhythm is an endogenous oscillation of about 24-h period in many physiological processes and behaviors. This daily oscillation is maintained by the molecular clock machinery with transcriptional-translational feedback loops mediated by clock genes including Period2 (Per2) and Bmal1. Recently, it was revealed that gut microbiome exerts a significant impact on the circadian physiology and behavior of its host; however, the mechanism through which it regulates the molecular clock has remained elusive. 3-(4-hydroxyphenyl)propionic acid (4-OH-PPA) and 3-phenylpropionic acid (PPA) are major metabolites exclusively produced by Clostridium sporogenes and may function as unique chemical messengers communicating with its host. In the present study, we examined if two C. sporogenes-derived metabolites can modulate the oscillation of mammalian molecular clock. Interestingly, 4-OH-PPA and PPA increased the amplitude of both PER2 and Bmal1 oscillation in a dosedependent manner following their administration immediately after the nadir or the peak of their rhythm. The phase of PER2 oscillation responded differently depending on the mode of administration of the metabolites. In addition, using an organotypic slice culture ex vivo, treatment with 4-OH-PPA increased the amplitude and lengthened the period of PER2 oscillation in the suprachiasmatic nucleus and other tissues. In summary, two C. sporogenes-derived metabolites are involved in the regulation of circadian oscillation of Per2 and Bmal1 clock genes in the host's peripheral and central clock machineries.

Kisspeptin Neuron-Specific and Self-Sustained Calcium Oscillation in the Hypothalamic Arcuate Nucleus of Neonatal Mice: Regulatory Factors of its Synchronization

INTRODUCTION

Synchronous and pulsatile neural activation of kisspeptin neurons in the arcuate nucleus (ARN) are important components of the gonadotropin-releasing hormone pulse generator, the final common pathway for central regulation of mammalian reproduction. However, whether ARN kisspeptin neurons can intrinsically generate self-sustained synchronous oscillations from the early neonatal period and how they are regulated remain unclear.

OBJECTIVE

This study aimed to examine the endogenous rhythmicity of ARN kisspeptin neurons and its neural regulation using a neonatal organotypic slice culture model.

METHODS

We monitored calcium (Ca2+) dynamics in real-time from individual ARN kisspeptin neurons in neonatal organotypic explant cultures of Kiss1-IRES-Cre mice transduced with genetically encoded Ca2+ indicators. Pharmacological approaches were employed to determine the regulations of kisspeptin neuron-specific Ca2+ oscillations. A chemogenetic approach was utilized to assess the contribution of ARN kisspeptin neurons to the population dynamics.

RESULTS

ARN kisspeptin neurons in neonatal organotypic cultures exhibited a robust synchronized Ca2+ oscillation with a period of approximately 3 min. Kisspeptin neuron-specific Ca2+ oscillations were dependent on voltage-gated sodium channels and regulated by endoplasmic reticulum-dependent Ca2+ homeostasis. Chemogenetic inhibition of kisspeptin neurons abolished synchronous Ca2+ oscillations, but the autocrine actions of the neuropeptides were marginally effective. Finally, neonatal ARN kisspeptin neurons were regulated by N-methyl-D-aspartate and gamma-aminobutyric acid receptor-mediated neurotransmission.

CONCLUSION

These data demonstrate that ARN kisspeptin neurons in organotypic cultures can generate synchronized and self-sustained Ca2+ oscillations. These oscillations controlled by multiple regulators within the ARN are a novel ultradian rhythm generator that is active during the early neonatal period.

Multidisciplinary clinic approach improves overall survival outcomes of patients with metastatic germ-cell tumors

Background

To report our experience utilizing a multidisciplinary clinic (MDC) at Indiana University (IU) since the publication of the International Germ Cell Cancer Collaborative Group (IGCCCG), and to compare our overall survival (OS) to that of the National Cancer Institute (NCI) Surveillance, Epidemiology, and End Results (SEER) Program.

Patients and methods

We conducted a retrospective analysis of all patients with metastatic germ-cell tumor (GCT) seen at IU from 1998 to 2014. A total of 1611 consecutive patients were identified, of whom 704 patients received an initial evaluation by our MDC (including medical oncology, pathology, urology and thoracic surgery) and started first-line chemotherapy at IU. These 704 patients were eligible for analysis. All patients in this cohort were treated with cisplatin-etoposide-based combination chemotherapy. We compared the progression-free survival (PFS) and OS of patients treated at IU with that of the published IGCCCG cohort. OS of the IU testis cancer primary cohort (n = 622) was further compared with the SEER data of 1283 patients labeled with 'distant' disease. The Kaplan-Meier method was used to estimate PFS and OS.

Results

With a median follow-up of 4.4 years, patients with good, intermediate, and poor risk disease by IGCCCG criteria treated at IU had 5-year PFS of 90%, 84%, and 54% and 5-year OS of 97%, 92%, and 73%, respectively. The 5-year PFS for all patients in the IU cohort was 79% [95% confidence interval (CI) 76% to 82%]. The 5-year OS for the IU cohort was 90% (95% CI 87% to 92%). IU testis cohort had 5-year OS 94% (95% CI 91% to 96%) versus 75% (95% CI 73% to 78%) for the SEER 'distant' cohort between 2000 and 2014, P-value <0.0001.

Conclusion

The MDC approach to GCT at high-volume cancer center associated with improved OS outcomes in this contemporary dataset. OS is significantly higher in the IU cohort compared with the IGCCCG and SEER 'distant' cohort.

Recent Progress in Organic Electrodes for Li and Na Rechargeable Batteries

Organic rechargeable batteries, which use organics as electrodes, are excellent candidates for next-generation energy storage systems because they offer design flexibility due to the rich chemistry of organics while being eco-friendly and potentially cost efficient. However, their widespread usage is limited by intrinsic problems such as poor electronic conductivity, easy dissolution into liquid electrolytes, and low volumetric energy density. New types of organic electrode materials with various redox centers or molecular structures have been developed over the past few decades. Moreover, research aimed at enhancing electrochemical properties via chemical tuning has been at the forefront of organic rechargeable batteries research in recent years, leading to significant progress in their performance. Here, an overview of the current developments of organic rechargeable batteries is presented, with a brief history of research in this field. Various strategies for improving organic electrode materials are discussed with respect to tuning intrinsic properties of organics using molecular modification and optimizing their properties at the electrode level. A comprehensive understanding of the progress in organic electrode materials is provided along with the fundamental science governing their performance in rechargeable batteries thus a guide is presented to the optimal design strategies to improve the electrochemical performance for next-generation battery systems.

Tin Sulfide-Based Nanohybrid for High-Performance Anode of Sodium-Ion Batteries

Nanohybrid anode materials for Na-ion batteries (NIBs) based on conversion and/or alloying reactions can provide significantly improved energy and power characteristics, while suffering from low Coulombic efficiency and unfavorable voltage properties. An NIB paper-type nanohybrid anode (PNA) based on tin sulfide nanoparticles and acid-treated multiwalled carbon nanotubes is reported. In 1 m NaPF₆ dissolved in diethylene glycol dimethyl ether as an electrolyte, the above PNA shows a high reversible capacity of ≈1200 mAh g^-1 and a large voltage plateau corresponding to a capacity of ≈550 mAh g^-1 in the low-voltage region of ≈0.1 V versus Na⁺ /Na, exhibiting high rate capabilities at a current rate of 1 A g^-1 and good cycling performance over 250 cycles. In addition, the PNA exhibits a high first Coulombic efficiency of ≈90%, achieving values above 99% during subsequent cycles. Furthermore, the feasibility of PNA usage is demonstrated by full-cell tests with a reported cathode, which results in high specific energy and power values of ≈256 Wh kg^-1 and 471 W kg^-1 , respectively, with stable cycling.

Advanced hybrid supercapacitor based on a mesoporous niobium pentoxide/carbon as high-performance anode

Recently, hybrid supercapacitors (HSCs), which combine the use of battery and supercapacitor, have been extensively studied in order to satisfy increasing demands for large energy density and high power capability in energy-storage devices. For this purpose, the requirement for anode materials that provide enhanced charge storage sites (high capacity) and accommodate fast charge transport (high rate capability) has increased. Herein, therefore, a preparation of nanocomposite as anode material is presented and an advanced HSC using it is thoroughly analyzed. The HSC comprises a mesoporous Nb2O5/carbon (m-Nb2O5-C) nanocomposite anode synthesized by a simple one-pot method using a block copolymer assisted self-assembly and commercial activated carbon (MSP-20) cathode under organic electrolyte. The m-Nb2O5-C anode provides high specific capacity with outstanding rate performance and cyclability, mainly stemming from its enhanced pseudocapacitive behavior through introduction of a carbon-coated mesostructure within a voltage range from 3.0 to 1.1 V (vs Li/Li(+)). The HSC using the m-Nb2O5-C anode and MSP-20 cathode exhibits excellent energy and power densities (74 W h kg(-1) and 18,510 W kg(-1)), with advanced cycle life (capacity retention: ∼90% at 1000 mA g(-1) after 1000 cycles) within potential range from 1.0 to 3.5 V. In particular, we note that the highest power density (18,510 W kg(-1)) of HSC is achieved at 15 W h kg(-1), which is the highest level among similar HSC systems previously reported. With further study, the HSCs developed in this work could be a next-generation energy-storage device, bridging the performance gap between conventional batteries and supercapacitors.

Ischemic preconditioning and nicorandil pretreatment improve donor heart preservation

The present study investigated the effects of ischemic preconditioning (IPC) and nicorandil pretreatment on myocardial storage in a donor heart preservation model. Isolated rat hearts were separated into groups: group 1, non-preconditioned control group; group 2, 2.5 min of normothermic ischemia followed by 15 min of normothermic Langendorff perfusion (one IPC cycle); and group 3, 2 cycles of IPC. All hearts were subsequently stored in University of Wisconsin solution at 4 degrees C for 2, 4 and 6h, and the concentrations of high-energy phosphate metabolites were measured for each time point. Heart function parameters (aortic flow, coronary flow and cardiac output) were measured when the heart was reperfused following the 2, 4 or 6 h of preservation. The effects of nicorandil, an ATP-sensitive potassium channel opener, on heart function following preservation were also evaluated. Nicorandil was injected intravenously before heart harvesting. The results showed that the energy status was well preserved in the IPC groups. The 2-cycle IPC group showed better recovery of heart function following preservation. Pretreatment with nicorandil also improved functional recovery of the heart following preservation. The present study showed that IPC of the rat heart resulted in improved myocardial energy metabolism and functional recovery after hypothermic preservation, and that nicorandil has potential for pharmacological preconditioning in heart preservation for transplantation.

Postischemic reperfusion injury can be attenuated by oxygen tension control

Oxygen-derived free radicals cause cytotoxic damage during reperfusion after a period of ischemia and the production of these free radicals may be proportionate to oxygen tension (PO2). The present study tested the hypothesis that oxidative damage may be limited by maintaining a more physiologic PO2 following ischemia. An experimental study in Wistar rats were mounted on a Langendorff apparatus was conducted to estimate baseline aortic flow (AF), coronary flow (CF), cardiac output (CO), systolic pressure (SP), heart rate (HR), and the rate-pressure product (RPP: HRxSP). The hearts were divided into 3 groups (n=7, hearts/group): group 1, hypoxic (PO2=300+/-50 mmHg) reperfusion; group 2, middleoxic (PO2=500+/-50 mmHg) reperfusion; and group 3, hyperoxic (PO2=700+/-50 mmHg) reperfusion. Following 30 min of warm ischemia, hearts in all groups were reperfused at each oxygen pressure. The recovery of cardiac function of each heart was measured at the end of reperfusion. Concentrations of lactate (LAC), lactate dehydrogenase (LDH), and creatine kinase (CK) in the coronary perfusate during reperfusion were measured. The recovery rate of CO, SP, and RPP in group 2 were all significantly better than in the other 2 groups. CK leakage in group 2 was significantly lower than in group 3. A clinical study was also conducted during elective coronary artery bypass grafts in 16 consecutive patients who underwent either hyperoxic (n=8, PO2=450-550 mmHg) or more physiologic (n=8, PO2=200-250 mmHg) cardiopulmonary bypass after aortic unclamping. The clinical study assessed CK-MB, LDH, LAC, and malondialdehyde (MDA) in patient blood prior to starting the surgical procedure and at 30 min and 3, 9, and 21 h after unclamping. Cardiac index (CI), central venous pressure, pulmonary capillary wedge pressure, systolic arterial pressure, and the dose of cathecholamines were also measured. Although no significant differences were present in the dose of cathecholamines, the CI in the more physiologic oxygen tension group was significantly higher than in the hyperoxic group at 3 and 6 h after unclamping. The levels of MDA in the more physiologic PO2 group was significantly lower at 30 min after aortic unclamping than in the hyperoxic group. The present results suggest that in the experimental as well as in the clinical study, high PO2 leads to myocardial reperfusion damage; however, maintaining a more physiologic PO2 during reperfusion following ischemia may attenuate reperfusion injury.

[Renal autotransplantation in a patient with acute renal infarction following surgery for a dissecting aneurysm]

A 58-year-old woman experienced a sudden onset of severe chest and back pain and thus visited our center in October 1999. Contrast-enhanced computed tomography (CT) revealed a Stanford type A acute aortic dissection. The CT also demonstrated a 50 mm ascending aorta and dissection from the ascending aorta via the abdominal aorta to the level of the left renal artery. The perioperative transesophageal echocardiogram showed an intimal tear in the ascending aorta without valvular abnormality. Therefore, we performed graft replacement of the ascending aorta. On the first postoperative day, she developed oliguria and showed a sudden rise in serum creatinine (Cr) and blood urea nitrogen (BUN) levels, necessitating hemodialysis. She required daily hemodialysis or hemofiltration for twenty days. Thereafter, renal function recovered and dialysis was no longer performed. However, on postoperative day 26, the patient complained of sudden lumber pain. Unheralded oliguria was associated with worsening renal function. A CT scan at this point revealed infarction of the left kidney. During surgery, the left kidney was excised for heterotopic autotransplantation. Extensive thrombosis within a true lumen of the left renal artery was revealed. Following removal of the thrombus and perfusion with heparinized cold saline, renal autotransplantation to a heterotopic site in the pelvis were performed. Although the patient required hemodialysis for five days, renal function recovered gradually. She was discharged five months later. In our experience, it appears that heterotopic renal autotransplantation by which normal arterial perfusion distal to the dissection is reestablished is a good therapeutic option for reperfusion of the ischemic kidney compromised by a progressive dissection of the thoracoabdominal aorta.

Mammary lipogenic enzyme activity, trans fatty acids and conjugated linoleic acids are altered in lactating dairy cows fed a milk fat-depressing diet

The objectives of the present study were to examine the effect of a milk fat-depressing (MFD) diet on: 1) the activity of mammary acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS), 2) ACC mRNA relative abundance and 3) distributions of conjugated linoleic acids (CLA) and trans-18:1 fatty acids (tFA) in milk fat. Twelve lactating Holstein cows were used in a single reversal design. Two diets were fed: a control diet (60:40% forage/concentrate) and an MFD diet (25:70% forage/concentrate, supplemented with 5% soybean oil). The MFD diet decreased (P: < 0 0.001) milk fat by 43% and ACC and FAS activity by 61 and 44%, respectively. A reduced ACC mRNA relative abundance (P: < 0.001) corresponded with the lower ACC activity. The fatty acids synthesized de novo were decreased (P: < 0. 002), whereas tFA were increased from 1.9 to 15.6% due predominantly to a change in trans-10-18:1 isomer (P: < 0.001). With the MFD diet, the trans-7, cis-9 and trans-10, cis-12 CLA isomers were elevated (P: < 0.001), in contrast to the decrease in trans-11-18:1 (P: < 0. 001) and cis-9, trans-11-18:2. The data were consistent with a dietary effect on mammary de novo FA synthesis mediated through a reduction in ACC and FAS activity and in ACC mRNA abundance. The results were compatible with a role of trans-10, cis-12 CLA in milk fat depression, but alterations noted in tFA and other CLA isomers suggest that they also may be important during diet-induced milk fat depression.

Heart preservation in HTK solution: role of coronary vasculature in recovery of cardiac function

BACKGROUND

Poor myocardial tolerance to prolonged cold ischemia remains a major concern in heart transplantation. In this study, we estimated superiority of Histidine-Tryptophan-Ketoglutarate (HTK) over University of Wisconsin (UW) as a cardiac preservation solution.

METHODS

Isolated rat hearts were mounted on a Langendorff apparatus to estimate the baseline cardiac function. The hearts were arrested and stored at 4 degrees C in UW and HTK solution for 8 hours, and then reperfused. The aortic flow, coronary flow, cardiac output, rate pressure product, and left ventricular dp/dt in the HTK group recovered significantly more than the UW group. The values of myocardial total adenine nucleotides and the adenosine triphosphate to adenosine diphosphate ratio were higher in the HTK than in the UW group. We also examined coronary vascular responsiveness using left coronary arteries dissected from the rat hearts before flushing, before storage, after storage, and after reperfusion.

RESULTS

The maximal relaxation response to acetylcholine was significantly higher in the HTK than in the UW group after reperfusion, although there were no significant differences at each stage before reperfusion. In addition, the endothelium-independent relaxation response to sodium nitroprusside in the HTK group was also well preserved after reperfusion.

CONCLUSIONS

These results indicate that HTK is superior to UW solution for cardiac preservation. HTK protects coronary vasculature during preservation, which together with reperfusion might lead to improved functional cardiac recovery following preservation.

Beneficial effects of omega-3 fatty acid treatment on the recovery of cardiac function after cold storage of hyperlipidemic rats

Cardiac effects of omega-3 polyunsaturated fatty acids (PUFAs) were studied in female Wister rats fed a standard diet (control [C] diet) or a high-cholesterol (HC) diet. Subgroups of rats from these groups were treated with eicosapentaenoic acid-E (EPA) or docosahexaenoic acid-95E (DHA) for 5 weeks. Although plasma total cholesterol (TC) and triglyceride (TG) levels were higher in each group fed the HC diet versus each group fed the C diet, EPA administration with the HC diet (HC + EPA) significantly (P < .05) reduced these levels. An isolated working-heart preparation was used to determine cardiac function. Cardiac output (CO) was lower in rats fed the HC diet and HC + DHA versus any of the groups fed the C diet (P < .05). In addition, left ventricular (LV) maximum differentiation of pressure-time curve (dp/dt) was lower in the rats fed the HC diet versus any of the C diet groups (P < .05). After evaluation of cardiac function in each rat, the heart was stored in a histidine-tryptophan-ketoglutarate solution for 8 hours at 4 degrees C. The heart was then reperfused, and recovery of cardiac function was evaluated. No significant differences were observed for post-preservative cardiac function within the C diet groups. However, within the HC diet groups, HC + EPA significantly (P < .05) improved the recovery of cardiac function. In addition, HC + DHA also significantly (P < .05) improved the recovery of coronary flow (CF) and LV dp/dt. No significant differences were observed for plasma TC and TG concentrations in the C diet groups. EPA administration significantly decreased cardiac levels of palmitic, oleic, and linoleic acids in the HC diet groups. No significant differences were observed for cardiac levels of free fatty acids (FFAs) within the C diet groups. Cardiac EPA and DHA levels were significantly (P < .05) elevated in EPA- or DHA-treated rats compared with the other diet-fed rats. Cardiac EPA levels were also elevated in DHA-treated rats compared with untreated rats (P < .05). These results suggest that EPA attenuates coronary and myocardial preservation injuries through an increase in serum lipids and an accumulation of myocardial FFAs resulting from a HC diet.

Refractoriness to platelet transfusion following double valve replacement in an ITP patient who had undergone splenectomy

Reports of patients with idiopathic thrombocytopenic purpura (ITP) undergoing cardiac surgery are rare, and almost all of the reported cases required platelet transfusion. ITP patients, especially those having a history of splenectomy or a history of heavy bleeding, may have to undergo multiple platelet transfusions. Such transfusions may induce alloimmunization against the human leukocyte antigen (HLA) and result in refractoriness to subsequent platelet transfusions. We report a case of a 63-year-old female with ITP, with a history of splenectomy and multiple platelet transfusions, who underwent aortic and mitral valve replacement. Although corticosteroid administration, high-dose immunoglobulin therapy, and repeated platelet transfusion led to a temporary increase in platelet count and successful hemostasis, refractoriness to platelet transfusion occurred postoperatively because of the presence of the anti-HLA antibody. In addition, the patient showed complications of pyothorax. Corticosteroids might have exerted an inhibitory influence on the occurrence of pyothorax.

Synthesis and cytotoxicity of methyl-4,8-dihydrobenzo[1,2-b:5,4-b']dithiophene-4,8-dione derivatives

2- and 3-Methyl-4,8-dihydrobenzo[1,2-b:5,4-b']dithiophene-4,8-dione and related derivatives were synthesized and evaluated in vitro by NCI against eight cancer types. Compounds 12-15 showed significant activity against melanoma, NCI-H23 non-small cell lung cancer, and MDA-MB-435 and MDA-N breast cancer cell lines; 2-hydroxymethyl-4,8-dihydrobenzo[1,2-b:5,4-b']dithiophene-4,8-dion e (13) showed the highest activity against melanoma (mean log GI50 = -7.74) and the highest overall potency (mean log GI50 = -6.99).

Abdominal aortic aneurysm rupture in systemic lupus erythematosus

Many cardiovascular complications have been described in systemic lupus erythematosus (SLE), however, aortic involvement is very rare. We are reporting abdominal aortic aneurysm rupture in a 47-year old woman with SLE. The patient was admitted to our hospital with severe abdominal pain. Emergency computed tomography of the abdomen demonstrated ruptured abdominal aortic aneurysm. The restoration of aortic flow with vascular prosthesis was performed in emergency. Postoperative course was uneventful.

Protective effects of nicaraven, a new hydroxyl radical scavenger, on the endothelial dysfunction after exposure of pig coronary artery to hydroxyl radicals

Recently, we have reported that a new synthetic compound, 1,2bis(nicotinamido)-propane (nicaraven), improved cardiac function following preservation and reperfusion. In this study, we investigated the efficacy of nicaraven as a radical scavenger by using an in vitro model of oxidative stress, to clarify mechanisms of the protective effect of this new compound on reperfusion injury in rat heart. Ring segments of epicardial right coronary arteries (RCA) of pig were suspended in organ chambers and exposed to hydroxyl radicals (.OH), generated (by two different systems) by 0.28 mM FeSO4/0.28 mM H2O2 and DHF/Fe3+-ADP (2.4 mM, 43 nM, and 1.56 uM, respectively) to the bathing solution for 60 min. Prior exposure of the coronary arteries to .OH significantly produced right-ward shift of the dose-response curves of the bradykinin-induced endothelium-dependent relaxations (an increase in the ED50 value for bradykinin by 4.37 and 1.98 times than control in two different .OH generating systems, respectively), but did not affect the maximum relaxation responses. The presence of nicaraven (10(-4) and 10(-5) M) in the .OH generating system, shifted the dose-response curves to bradykinin to the control level, suggesting a significant hydroxyl radical scavenging effect of the drug. These results indicate that nicaraven, a new hydroxyl radical scavenger, exhibits a protective effect on hydroxyl radical-induced endothelial dysfunctions of pig coronary artery.

Prolonged hypothermic cardiac storage with histidine-tryptophan-ketoglutarate solution: comparison with glucose-insulin-potassium and University of Wisconsin solutions

BACKGROUND

The purpose of this study was to compare the efficacy of histidine-tryptophan-ketoglutarate (HTK) solution after prolonged cold storage with that of the conventional glucose-insulin-potassium (GIK) and University of Wisconsin (UW) solutions in experimental heart preservation. GIK solution was chosen as a control to mimic current clinical regimens. Variables of cardiac function, myocardial tissue water, and adenine nucleotide pool metabolites were used to assess prolonged myocardial preservation in the isolated rat heart model.

METHODS

Hearts isolated from male Wistar rats were mounted on a Langendorff apparatus to estimate baseline cardiac function. The hearts were divided into three groups (n=6 per group) according to each preservation solution used: group 1, GIK solution; group 2, UW solution; and group 3, HTK solution. The hearts were then arrested and stored in each solution for 6, 8, and 12 hr at 4 degrees C. After storage, the hearts were reperfused and recovery of cardiac function and myocardial tissue water content were evaluated. Myocardial adenylate contents just after storage in each group (n=5 hearts/group) were also measured.

RESULTS

The hearts stored in HTK solution showed maintenance of cardiac function at up to 8 hr of almost 80% of prepreservative baseline function; however, recovery of cardiac function of the hearts stored in UW solution revealed an initial loss of function at 6 hr of almost 60% and a decline to 50% at 8 hr. Furthermore, recovery of cardiac function of the hearts stored in GIK solution revealed a progressive loss of function at 6 hr of storage of almost 50% and a decline to 30% at 8 hr of storage. The myocardial ATP/ADP ratios after 6 hr of storage in HTK and UW solutions were significantly higher than the ratio found in GIK solution. Although the myocardial ATP/ADP ratio after 8 hr of storage in HTK solution was maintained above 50%, the ratios in GIK and UW solutions declined to 15%. In addition, the myocardial energy charge values of the hearts stored in HTK solution were sufficiently maintained until 8 hr of storage, whereas the values in UW and GIK solutions declined to below 50% at 6 hr of storage and 20% at 8 hr of storage. Although there were no significant differences in tissue water contents after 6 and 8 hr of storage among the three groups, the water contents of the hearts after 12 hr of storage in HTK and UW solutions were significantly lower than that of the hearts stored in GIK solution.

CONCLUSIONS

Our results suggest that HTK solution is much more effective than UW and GIK solutions for isolated rat heart preservation; however, successful cold storage of the heart is highly energy-dependent, and a dramatic breakdown of myocardial energy level, which causes a crucial decline in cardiac function, occurs between 8 and 12 hr of storage.

[Tricuspid valve replacement for infectious endocarditis associated with ventricular septal defect--report of three cases]

We reported two male and one female patient (17, 36 and 47 years old, respectively) who presented infectious endocarditis (IE) in association with ventricular septal defect (VSD). In all cases, surgical treatment was performed in the acute stage of IE for persistent sepsis, pulmonary embolisms, and for giant vegetations. Because the tricuspid valve apparatus was severely damaged, valve replacement with the Carpentier-Edwards pericardial bioprosthesis was done and small VSD was directly closed in all cases. In one case, a complete heart block occurred, which necessitated postoperative implantation of a permanent pacemaker. All patients recovered and resumed their original social activities without the relapse of endocarditis.

Influences of dietary omega-3 polyunsaturated fatty acids on the recovery of cardiac and renal functions after preservation in hyperlipidemic rats

BACKGROUND

The effects of a soybean oil diet and a high-cholesterol oil (HC) diet, and an HC diet with eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) supplementation, on basal and postpreservative cardiac function of the hearts and on postpreservative renal function of the kidneys from older rats were examined.

METHODS

Groups 1 through 4 of 100-week-old rats were fed either soybean oil, HC, HC with EPA, or HC with DHA, respectively, for 12 weeks. Blood was collected for analysis of plasma fatty acids, and the heart and left kidney were removed from the rat. In experiment 1, the heart was perfused on a Langendorff apparatus. After evaluation of the cardiac function of each rat, the heart was stored in histidine-tryptophan-ketoglutarate solution for 8 hr at 4 degrees C. The heart was reperfused and the recovery of cardiac function was evaluated. The coronary perfusate during reperfusion was collected to measure 6-keto prostaglandin F1alpha and thromboxane B2. Coronary flow (CF) perfused with Krebs-Henseleit bicarbonate (KHB) solution containing 5-hydroxytryptamine (5-HT) and nitroglycerin were evaluated in the Langendorff mode with atrial pacing (330 beats/min). In experiment 2, the excised left kidney was immediately flushed and preserved with University of Wisconsin solution for 8 hr at 4 degrees C. The kidney was then reperfused with KHB solution and renal function was evaluated.

RESULTS

The plasma and cardiac EPA levels in group 3 were significantly higher than the levels found in the other groups. The plasma and cardiac ratios of EPA to arachidonic acid were significantly higher in groups 3 and 4 than in groups 1 and 2. There were no significant differences in basal cardiac function among any of the diet-fed rats. The percentage values of the recovery of aortic flow, cardiac output (CO), and left ventricular max dp/dt in group 3 and CO in group 4 were significantly higher than in group 2. In addition, the recovery of CF in group 3 tended to be higher than in group 2 (P=0.07). The percentage values of the recovery of aortic flow, CF, CO, and left ventricular max dp/dt in group 1 were significantly lower than in the other dietary groups. CF reperfused with KHB solution containing 5-HT was significantly higher in group 3 than in groups 1 and 2. CF reperfused with KHB solution containing 5-HT was significantly higher in group 4 than in group 1. CF reperfused with KHB solution containing nitroglycerin in group 3 tended to be higher than in groups 1 and 2 (P=0.07). The thromboxame B2 concentrations in the coronary perfusate during reperfusion in groups 3 and 4 were significantly lower than in groups 1 and 2. Fractional sodium reabsorption in group 3 was significantly higher than in group 2. Inulin clearance in groups 3 and 4 was significantly higher than in group 1. The postpreservative urinary flow in group 3 was significantly higher than in groups 1 and 2. The urinary flow was significantly higher in group 4 than in group 1.

CONCLUSIONS

These results suggest that EPA administration may attenuate preservation and reperfusion injury and improve the recovery of cardiac and renal functions in hyperlipidemic and older rats. DHA administration may also show beneficial effects on kidney preservation in hyperlipidemic rats.

Long-term follow-up (8 to 17 years) after thromboexclusion operation for thoracic aortic aneurysms

BACKGROUND

It has been reported that the thromboexclusion operation is a good method for managing certain difficult thoracic aortic aneurysms.

METHODS

Forty-four patients underwent graft replacement (group 1) and 14, the thromboexclusion operation (group 2). We reviewed the long-term results of the thromboexclusion operation and compared them with those of graft replacement in our institutions.

RESULTS

The hospital mortality rate in groups 1 and 2 was 29.5% (13 patients) and 35.7% (4 patients), respectively. In group 1, the one late death (2.3%) was due to heart failure and in group 2, three of the four late deaths (28.6%) were due to rupture of the excluded thoracic aorta, and one late death was due to heart failure. Long-term follow-up was possible for 23 patients in group 1 and 5 patients in group 2. Survival 3 years after operation was significantly better in group 1 than in group 2 (p < 0.05). Long-term follow-up with blood pressure measurements, chest roentgenograms, electrocardiograms, and echocardiograms showed no significant differences between the preoperative and postoperative findings. However, in group 2, left ventricular hypertrophy and hypertension, which had not been present preoperatively, were found in all of the patients. Also, 1 patient has had persistent hemoptysis.

CONCLUSIONS

The thromboexclusion operation has introduced unanticipated problems that were recognized at long-term follow-up.

Antithrombotic effects of endocardial endothelial cells-comparison with coronary artery endothelial cells

The purpose of this study was to assess the anti-platelet properties of endocardial endothelial cells (EECs) by measuring platelet aggregation after a brief incubation with cultured EECs. EECs were isolated from the right ventricles of porcine hearts and coronary artery endothelial cells (C-ECs) were also isolated from the same animals. After brief incubations (2-min) of platelet suspensions with cultured EEC and CEC monolayers, platelet aggregation in response to thrombin and 6-keto-PGF1 alpha (a stable metabolite of PGI2) content of platelet suspensions were measured. Platelet aggregation was significantly inhibited by a brief incubation of platelet suspensions with EEC and C-ECs monolayers. Pretreatment of EECs and C-ECs with indomethacin (5 x 10(-5) M) restored platelet activity, but pretreatment with N omega-nitro-L-arginine methyl ester (L-NAME, 5 x 10(-5) M) or hemoglobin (1 x 10(-6) M) did not. Platelet/EEC interactions multiplicatively increased the 6-keto-PGF1 alpha content of platelet suspensions and the 6-keto-PGF1 alpha content of platelet suspensions after incubations with EECs correlated significantly with the inhibition of platelet aggregation. Both the anti-aggregation properties and 6-keto-PGF1 alpha production were significantly greater in EECs than in C-ECs. A brief incubation (2-min) with PDGF (10 ng/ml) or TGF-beta (1 and 10 ng/ml) stimulated 6-keto-PGF1 alpha production in EECs but not in C-ECs, although these growth factors stimulated 6-keto-PGF1 alpha production in C-ECs after a longer incubation time (30 or 60 min). In this study, after a brief incubation (2-min) with platelet suspensions, EECs inhibited platelet aggregation mainly through the release of PGI2 but not EDRF. As this anti-aggregation property was significantly greater in EECs than in C-ECs, it is suggested that endocardial endothelial PGI2 may inhibit both intracardiac and intracoronary artery thrombus formation, contributing to the prevention of myocardial ischemia.

The effects of transmural pressure on prostacyclin release from porcine endocardial endothelial cells--comparison with vascular endothelial cells

We assessed the effect of pressure on the release of prostacyclin (PGI2) from cultured endocardial endothelial cells (EECs) and vascular endothelial cells (VECs). EECs were harvested from the right ventricle (RV) and left ventricle (LV) of porcine hearts, and VECs from pulmonary artery (PA), aorta (Ao) and coronary artery (CA). Confluent EECs and VECs were incubated for 30 min under various pressures (0, 50, 100, 150 mmHg) and PGI2 release from each cell was measured. Pressure-induced PGI2 release from LV-EECs was larger than that from RV-EECs. Pressure also increased PGI2 release from both PA- and Ao-VECs, but not from CA-VECs. These findings suggest that endocardium can produce PGI2 in response to pressure and PGI2 released into the coronary blood from the ventricle may play an important role in the prevention of myocardial ischemia.

Hydroxyl radical scavenging effect of nicaraven in myocardial and coronary endothelial preservation and reperfusion injury

OBJECTIVE

We investigated the efficacy of nicaraven in reducing myocardial as well as coronary endothelial preservation-reperfusion (P/R) injury.

METHODS

In experiment I, isolated rat hearts were mounted on a Langendorff (L) apparatus to estimate the baseline cardiac function. Group 1, 8- and 12-h storage in histidine-tryptophan-ketoglutarate (HTK) solution; group 2, 8- and 12-h storage in HTK solution with superoxide dismutase (2.5 x 10(5) U/I) and catalase (2 x 10(5) U/I); group 3, 8- and 12-h storage in HTK solution with nicaraven (10(-3) M). Following storage for 8 and 12 h at 4 degrees C, they were reperfused and post-preservative cardiac function was evaluated. The hearts were then switched back to L-mode and paced at 330 beats/min. Coronary flow (CF) following perfusion with KHB solution containing 5-hydroxytryptamine (5-HT) and nitroglycerin was also measured. In experiment 2, segments of pig coronary artery were suspended in organ chambers and exposed to hydroxyl radicals in the presence or absence of nicaraven. The sensitivity of relaxation response to bradykinin of the prior-exposed rings was measured.

RESULTS

The recovery of CF and LV dp/dt following 8 h of storage in group 3 was higher than that in group 1, although there were no significant differences in the other parameters of cardiac functional recovery among the groups. The absolute values of cardiac function following 12 h of storage in groups 1-3 were as follows: 6.6 +/- 2.4, 9.1 +/- 0.8, 15.6 +/- 3.1 ml/min of cardiac output (CO); 1.9 +/- 0.9, 2.3 +/- 0.4, 6.0 +/- 2.3 ml/min of aortic flow (AF); 4.5 +/- 1.3, 6.0 +/- 0.5, 9.5 +/- 0.8 ml/min of CF, respectively. The recovery of CO, AF, CF, SP, MP, and left ventricular (LV) dp/dt were significantly improved in group 3, compared with those in group 1. CF and CO in group 3 were higher than those in group 2.5-HT caused vasoconstriction in all groups, but the vasoconstriction in group 3 was less than in group 1. Prior exposure to FeSO4/H2O2 produced significant endothelial damage as reflected by the right-ward shift of the dose-response curve of bradykinin-induced endothelium-dependent relaxation. In the presence on nicaraven, the dose-response curve recovered to the control level.

CONCLUSIONS

Nicaraven may improve coronary endothelial and myocardial function following P/R by its hydroxyl radical scavenging activity.

The role of a hydroxyl radical scavenger (nicaraven) in recovery of cardiac function following preservation and reperfusion

We investigated the efficacy in reducing myocardial preservation and reperfusion (P/R) injury of direct hydroxyl radical scavenging by nicaraven as compared with scavenging of both superoxide radicals and hydrogen peroxides by superoxide dismutase (SOD) and catalase (CAT), respectively. Isolated rat hearts were mounted on a Langendorff (L) apparatus to estimate the baseline aortic flow (AF), coronary flow (CF), cardiac output (CO), systolic pressure (SP), aortic mean pressure (MP), rate pressure product, and LV dp/dt. They were divided into 3 groups: group 1, 12 hr storage in HTK solution; group 2, 12 hr storage in HTK solution containing 2.5x10(5) U/L SOD and 2x10(5) U/L mg/L CAT; and Group 3, 12 hr storage in HTK solution containing 10(-3) M nicaraven. SOD, CAT, and nicaraven were administered intraperitoneally before harvesting. Hearts were stored in each preservation solution at 4, and then reperfused. Postpreservative function and concentrations of leaked enzymes were measured. The hearts were switched back to the L-mode and paced at 330 beats/min. CF following perfusion with Krebs-Henseleit bicarbonate buffer (KHB) solution containing 10(-6) M 5-hydroxytryptamine (5-HT) or 10(-5) M nitroglycerin (NTG) then evaluated. The myocardial water content also was measured. The recovery of CF, CO, SP, MP, and LV dp/dt was significantly greater in group 3 than in group 1. The recovery of CF was superior to that in group 2 (P<0.05). There were no significant differences in the recovery of cardiac function between groups 1 and 2. 5-HT caused a decrease in CF in each group, however, CF in group 3 was higher than that in group 1 (P<0.05). NTG caused no significant differences among the groups. There were no significant differences in leaked enzymes and myocardial water content among the three groups. These results suggest that nicaraven protects against myocardial P/R injury through its hydroxyl radical scavenging activity, and that therapy with oxygen-free radical scavengers should be directed toward inactivation of hydroxyl radicals rather than superoxide radicals and/or hydrogen peroxides.

The effects of omega-3 polyunsaturated (correction of polyunsatulated) fatty acids on the recovery of cardiac function following cold preservation and reperfusion in hyperlipidemic rats

We examined the effects of supplementation with eiosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), major components of omega-3 polyunsaturated (correction of polyunsatulated) fatty acids (PUFAs), on basal cardiac function and recovery of cardiac function of "donor hearts" from adults (30 week) rats following cold preservation and reperfusion (P/R). In groups 1, 2, 3, and 4, respectively, 30-week-old rats were fed a soybean oil diet, a high-cholesterol oil (HC) diet, an HC diet with EPA, or an HC diet with DHA for 5 weeks. After collecting blood to analyze plasma levels of fatty acids among each group, the heart was excised and perfused on a Langendorff apparatus. Following evaluation of each rat's cardiac function, each heart was stored in HTK solution for 8 hr at 4 degrees C. The heart was then reperfused and the coronary perfusate was collected to evaluate enzyme that had leaked. After cardiac functional recovery was estimated, myocardial fatty acids were measured. EPA supplementation significantly increases the plasma and cardiac levels of EPA as well as the ratio of EPA to arachidonic acid (AA). EPA supplementation also led to improved recovery of cardiac function following P/P, compared with that of rats who received soybean oil, high-cholesterol oil, and DHA. DHA supplementation significantly increased the plasma and cardiac levels of DHA as well as the ratio of DHA to AA--however, the cardiac functional recovery was almost identical to that of the rats who received high-cholesterol oil and was higher only than that of the rats who received soybean oil. There were no significant differences in enzyme that had leaked and myocardial water content among each group. These results suggest that alterations in the myocardial phospholipid composition by EPA supplementation may be profoundly responsible for attenuating myocardial I/R injuries. In contrast, DHA supplementation may not exert a cardioprotective effect following cold P/R. DHA supplementation alone may not increase the myocardial level of EPA enough to cause a protective effect against P/R injury. EPA supplementation to hyperlipidemic patients may be clinically warranted for increasing the potential number of donors.

Cyclic AMP-dependent and -independent protein kinases and protein phosphorylation in human promyelocytic leukemia (HL60) cells induced to differentiate by retinoic acid

The human leukemia cell line HL60 which resembles promyelocytes can be induced to differentiate to cells displaying features of the mature myeloid phenotype by a variety of agents including retinoic acid (RA) and agents that elevate intracellular adenosine 3:5 cyclic monophosphate (cyclic AMP) levels, e.g., 8-bromo-cyclic adenosine 3:5 monophosphate (8-Br-cyclic AMP), cholera toxin. Since most, if not all the effects of cyclic AMP, are mediated by adenosine 3:5 cyclic monophosphate-dependent protein kinase (cyclic AMP-dPK), we investigated the role of cyclic AMP-dPK and adenosine 3:5 cyclic monophosphate-independent protein kinase (cyclic AMP-iPK) in the induced differentiation of HL60 cells. Marked stimulation of cyclic AMP-dPK and cyclic AMP-iPK appears to be intimately involved with and specific for HL60 myeloid differentiation as evidenced by: (1) Stimulation of cyclic AMP-dPK and cyclic AMP-iPK early during HL60 myeloid differentiation and prior to phenotypic changes. (2) RA and dimethylformamide (DMF), agents that induce differentiation along the myeloid pathway, cause a marked increase in the type l cytosolic cyclic AMP-dPK and cyclic AMP-iPK (protamine kinase) while no such increases are noted in cells treated with 12-0-tetradecanoyl-phorbol-13-acetate (TPA) which induces differentiation along the monocyte/macrophage pathway. (3) Both native polyacrylamide gel electrophoresis as well as photoaffinity labeling with 8-azido-cyclic AMP demonstrate marked increases in type l cyclic AMP-dPK in the cytosols of cells exposed to agents that induce myeloid differentiation but no increase in TPA-differentiated cells. (4) The appearance and disappearance of specific cyclic AMP-dependent and -independent protein phosphorylations are associated with the induced myeloid differentiated state.