Acute myocardial infarction and acute upper gastrointestinal bleeding are both critical internal medicine conditions. The incidence of acute upper gastrointestinal bleeding in patients with acute myocardial infarction ranges from 5.31% to 8.90%, with a mortality rate as high as 20.50% to 35.70%. The pathogenesis may be related to the use of antiplatelet and anticoagulant drugs, as well as stress-induced injury. In treatment, the contradiction between antiplatelet/anticoagulation therapy and bleeding has made this disease a significant challenge in modern medicine. Therefore, re-exploring the etiology, pathogenesis, treatment principles, and methods of traditional Chinese medicine(TCM) for acute myocardial infarction and acute upper gastrointestinal bleeding is of great clinical importance. The research team has been working year-round in the coronary care unit(CCU), managing a large number of such severe patients. By revisiting classic texts and delving into the foundational theories of TCM and historical medical literature, it has been found that this disease falls under the category of "distant blood" in the Synopsis of the Golden Chamber. In terms of etiology, it is primarily associated with weakness of healthy Qi and damage caused by drug toxicity. In terms of pathogenesis, in the acute stage, it mainly manifests as insufficient spleen Yang, deficiency of spleen Qi, and failure of the spleen to control blood. In the remission stage, it is characterized by deficiency of both heart Qi and spleen blood. For treatment, during the acute stage, Huangtu Decoction is used to warm Yang and restrain blood, while in the remission stage, Guipi Decoction is administered to tonify Qi and nourish blood. During the treatment process, for patients with acute myocardial infarction complicated with acute upper gastrointestinal bleeding, it is crucial to flexibly apply the treatment principles of "Nil per os" in western medicine and "where there is stomach Qi, there is life; where there is no stomach Qi, there is death" in TCM. Early intervention with Huangtu Decoction can also prevent bleeding, with large doses being key to achieving hemostasis. It is important to address the pathogenesis of heat syndrome in addition to the core pathogenesis of Yang deficiency bleeding and to emphasize the follow-up treatment with Guipi Decoction for a successful outcome.
Humans ; Gastrointestinal Hemorrhage/etiology* ; Myocardial Infarction/drug therapy* ; Drugs, Chinese Herbal/therapeutic use* ; Medicine, Chinese Traditional ; Acute Disease

This study aims to explore the protective effect of Chaihu Jia Longgu Muli Decoction on rats with heart failure after myocardial infarction, and to clarify its possible mechanisms, providing a new basis for basic research on the mechanism of classic Chinese medicinal formula-mediated inflammatory response in preventing and treating heart failure induced by apoptosis after myocardial infarction. A heart failure model after myocardial infarction was established in rats by coronary artery ligation. The rats were divided into sham group, model group, and low, medium, and high-dose groups of Chaihu Jia Longgu Muli Decoction, with 10 rats in each group. The low-dose, medium-dose, and high-dose groups of Chaihu Jia Longgu Muli Decoction were given 6.3, 12.6, and 25.2 g·kg~(-1) doses by gavage, respectively. The sham group and model group were given an equal volume of distilled water by gavage once daily for four consecutive weeks. Cardiac function was assessed using color Doppler echocardiography. Myocardial pathology was detected by hematoxylin-eosin(HE) staining, apoptosis was measured by TUNEL assay, and mitophagy was observed by transmission electron microscopy. The levels of tumor necrosis factor-α(TNF-α), interleukin(IL)-1β, and N-terminal pro-B-type natriuretic peptide(NT-proBNP) in serum were detected by enzyme-linked immunosorbent assay(ELISA). The expression of apoptosis-related proteins B-cell lymphoma 2(Bcl-2), Bcl-2-associated X protein(Bax), and cleaved caspase-3 was detected by Western blot. Additionally, the expression of phosphorylated nuclear transcription factor-κB(NF-κB) p65(p-NF-κB p65)(upstream) and nuclear factor kappa B inhibitor alpha(IκBα)(downstream) in the NF-κB signaling pathway was assessed by Western blot. The results showed that compared with the sham group, left ventricular ejection fraction(LVEF) and left ventricular short axis shortening(LVFS) in the model group were significantly reduced, while left ventricular end diastolic diameter(LVEDD) and left ventricular end systolic diameter(LVESD) increased significantly. Myocardial tissue damage was severe, with widened intercellular spaces and disorganized cell arrangement. The apoptosis rate was increased, and mitochondria were enlarged with increased vacuoles. Levels of TNF-α, IL-1β, and NT-proBNP were elevated, indicating an obvious inflammatory response. The expression of pro-apoptotic factors Bax and cleaved caspase-3 increased, while the anti-apoptotic factor Bcl-2 decreased. The expression of p-NF-κB p65 was upregulated, and the expression of IκBα was downregulated. In contrast, the Chaihu Jia Longgu Muli Decoction groups showed significantly improved of LVEF, LVFS and decreased LVEDD, LVESD compared to the model group. Myocardial tissue damage was alleviated, and intercellular spaces were reduced. The apoptosis rate decreased, mitochondrial volume decreased, and the levels of TNF-α, IL-1β, and NT-proBNP were lower. The expression of pro-apoptotic factors Bax and cleaved caspase-3 decreased, while the expression of the anti-apoptotic factor Bcl-2 increased. Additionally, the expression of p-NF-κB p65 decreased, while IκBα expression increased. In summary, this experimental study shows that Chaihu Jia Longgu Muli Decoction can reduce the inflammatory response and apoptosis rate in rats with heart failure after myocardial infarction, which may be related to the regulation of the IκBα/NF-κB signaling pathway.
Animals ; Apoptosis/drug effects* ; Drugs, Chinese Herbal/administration & dosage* ; Rats ; Myocardial Infarction/physiopathology* ; Male ; NF-kappa B/genetics* ; Heart Failure/etiology* ; Rats, Sprague-Dawley ; Signal Transduction/drug effects* ; NF-KappaB Inhibitor alpha/genetics* ; Humans ; Tumor Necrosis Factor-alpha/genetics*

In the present study, a mouse model of coronary artery ligation was employed to evaluate the effects of Jiming Powder on mitophagy in the mouse model of myocardial infarction and elucidate its underlying mechanisms. A mouse model of myocardial infarction post heart failure was constructed by ligating the left anterior descending branch of the coronary artery. The therapeutic efficacy of Jiming Powder was assessed from multiple perspectives, including ultrasonographic imaging, hematoxylin-eosin(HE) staining, Masson staining, and serum cardiac enzyme profiling. Dihydroethidium(DHE) staining was employed to evaluate the oxidative stress levels in the hearts of mice from each group. Mitophagy levels were assessed by scanning electron microscopy and immunofluorescence co-localization. Western blot was employed to determine the levels of key proteins involved in mitophagy, including Bcl-2-interacting protein beclin 1(BECN1), sequestosome 1(SQSTM1), microtubule-associated protein 1 light chain 3 beta(LC3B), PTEN-induced putative kinase 1(PINK1), phospho-Parkinson disease protein(p-Parkin), and Parkinson disease protein(Parkin). The results demonstrated that compared with the model group, high and low doses of Jiming Powder significantly reduced the left ventricular internal diameter in systole(LVIDs) and left ventricular internal diameter in diastole(LVIDd) and markedly improved the left ventricular ejection fraction(LVEF) and left ventricular fractional shortening(LVFS), effectively improving the cardiac function in post-myocardial infarction mice. Jiming Powder effectively reduced the levels of myocardial injury markers such as creatine kinase(CK), creatine kinase isoenzyme(CK-MB), and lactate dehydrogenase(LDH), thereby protecting ischemic myocardium. HE staining revealed that Jiming Powder attenuated inflammatory cell infiltration after myocardial infarction. Masson staining indicated that Jiming Powder effectively inhibited ventricular remodeling. Western blot results showed that Jiming Powder activated the PINK1-Parkin pathway, up-regulated the protein level of BECN1, down-regulated the protein level of SQSTM1, and increased the LC3Ⅱ/LC3Ⅰ ratio to promote mitophagy. In conclusion, Jiming Powder exerts therapeutic effects on myocardial infarction by inhibiting ventricular remodeling. The findings pave the way for subsequent pharmacological studies on the active components of Jiming Powder.
Animals ; Myocardial Infarction/physiopathology* ; Mitophagy/drug effects* ; Mice ; Drugs, Chinese Herbal/administration & dosage* ; Protein Kinases/genetics* ; Male ; Ubiquitin-Protein Ligases/genetics* ; Humans ; Disease Models, Animal ; Mice, Inbred C57BL ; Signal Transduction/drug effects*

The medicinal materials of Bawei Chenxiang Pills(BCPs) were extracted via three methods: reflux extraction by water, reflux extraction by 70% ethanol, and extraction by pure water following reflux extraction by 70% ethanol, yielding three extracts of ST, CT, and CST. The efficacy of ST(760 mg·kg~(-1)), CT(620 mg·kg~(-1)), and CST(1 040 mg·kg~(-1)) were evaluated by acute myocardial ischemia(AMI) and p-chlorophenylalanine(PCPA)-induced insomnia in mice, respectively. Western blot was further utilized to investigate their hypnosis mechanisms. The main chemical components of different extracts were identified by the UPLC-Q-Exactive-MS technique. The results showed that CT and CST significantly increased the ejection fraction(EF) and fractional shortening(FS) of myocardial infarction mice, reduced left ventricular internal dimension at end-diastole(LVIDd) and left ventricular internal dimension at end-systole(LVIDs). In contrast, ST did not exhibit significant effects on these parameters. In the insomnia model, CT significantly reduced sleep latency and prolonged sleep duration, whereas ST only prolonged sleep duration without shortening sleep latency. CST showed no significant effects on either sleep latency or sleep duration. Additionally, both CT and ST upregulated glutamic acid decarboxylase 67(GAD67) protein expression in brain tissue. A total of 15 main chemical components were identified from CT, including 2-(2-phenylethyl) chromone and 6-methoxy-2-(2-phenylethyl) chromone. Six chemical components including chebulidic acid were identified from ST. The results suggested that chromones and terpenes were potential anti-myocardial ischemia drugs of BCPs, and tannin and phenolic acids were potential hypnosis drugs. This study enriches the pharmacological and chemical research of BCPs, providing a basis and reference for their secondary development, quality standard improvement, and clinical application.
Animals ; Drugs, Chinese Herbal/isolation & purification* ; Mice ; Male ; Sleep Initiation and Maintenance Disorders/physiopathology* ; Humans ; Myocardial Infarction/drug therapy* ; Myocardial Ischemia/drug therapy*

This study employed a mouse model of coronary artery ligation to assess the effect and mechanism of Jiming Powder on mitochondrial autophagy in mice with myocardial infarction. The mouse model of heart failure post-myocardial infarction was established by ligating the left anterior descending coronary artery. The pharmacological efficacy of Jiming Powder was evaluated through echocardiographic imaging, hematoxylin-eosin(HE) staining, and Masson staining. The levels of malondialdehyde(MDA), Fe~(2+), reduced glutathione(GSH), and superoxide dismutase(SOD) in heart tissues, as well as MDA immunofluorescence of heart tissues, were measured to assess lipid peroxidation and Fe~(2+) levels in the hearts of mice in different groups. Ferroptosis levels in the groups were evaluated using scanning electron microscopy and Prussian blue staining. Western blot analysis was conducted to detect the levels of key ferroptosis-related proteins, including nuclear factor erythroid 2-related factor 2(NRF2), ferritin heavy chain(FTH), glutathione peroxidase 4(GPX4), solute carrier family 7 member 11(SLC7A11), heme oxygenase 1(HO-1), and Kelch-like ECH-associated protein 1(KEAP1). The results showed that compared with the model group, both the high-and low-dose Jiming Powder groups exhibited significantly reduced left ventricular internal diameter in systole(LVIDs) and left ventricular internal diameter in diastole(LVIDd), while the left ventricular ejection fraction(EF) and left ventricular fractional shortening(FS) were significantly improved, effectively enhancing cardiac function in mice post-myocardial infarction. HE staining revealed that Jiming Powder attenuated myocardial inflammatory cell infiltration post-infarction, and Masson staining indicated that Jiming Powder effectively reduced fibrosis in the infarct margin area. Treatment with Jiming Powder reduced the levels of MDA and Fe~(2+), indicators of lipid peroxidation post-myocardial infarction, while increasing GSH and SOD levels, thus protecting ischemic myocardium. Western blot results demonstrated that Jiming Powder reduced KEAP1 protein accumulation, activated the NRF2/HO-1/GPX4 pathway, and up-regulated the protein expression of FTH and SLC7A11, exerting an inhibitory effect on ferroptosis. This study reveals that Jiming Powder exerts a therapeutic effect on myocardial infarction by inhibiting ferroptosis through the NRF2/HO-1/GPX4 pathway, providing a foundation for subsequent research on the pharmacological effects of Jiming Powder.
Animals ; Ferroptosis/drug effects* ; Myocardial Infarction/physiopathology* ; NF-E2-Related Factor 2/genetics* ; Mice ; Drugs, Chinese Herbal/administration & dosage* ; Male ; Heme Oxygenase-1/genetics* ; Phospholipid Hydroperoxide Glutathione Peroxidase/genetics* ; Humans ; Mice, Inbred C57BL ; Signal Transduction/drug effects* ; Disease Models, Animal

Objective To investigate the impact of Astragaloside-IV (AS-IV) on the progression of myocardial infarction (MI) through macrophage-dependent mechanisms by regulating Snail1 lactylation and acetylation, as well as the transforming growth factor β (TGF-β) pathway. Methods Oxygen glucose deprivation (OGD) was used to establish an in vitro myocardial ischemia model in rat cardiomyocytes (H9c2), which were then treated with AS-IV. Cell viability was assessed using CCK-8, apoptosis was evaluated by flow cytometry, and LDH levels were measured to assess cellular damage. RAW246.7 cells were treated with LPS, and lactate levels in the supernatant were measured using ELISA, while expression of macrophage phenotype markers was evaluated using Western blot. RAW246.7 cell-conditioned medium (CM) was co-cultured with H9c2 cells to assess the protective effects of AS-IV on macrophage CM-mediated H9c2 damage. RAW246.7 cells were induced to differentiate into M1-like macrophages using LPS (100 ng/mL) + IFN-γ (20 ng/mL), and Snail1 was overexpressed in M1 macrophages. Transfected M1 macrophage CM was co-cultured with H9c2 cells to validate the mechanisms of AS-IV in MI. An MI rat model was established by ligation of the left anterior descending coronary artery (LAD), and was treated with AS-IV. Cardiac function, myocardial cell apoptosis, and cardiac tissue pathology were studied using echocardiography, TUNEL, and HE staining, respectively. Results Compared to the OGD group, AS-IV treatment promoted cell viability, reduced apoptosis and decreased LDH release. LPS upregulated lactate levels in the supernatant of RAW246.7 cell cultures and induced polarization of RAW246.7 cells to the M1 phenotype. AS-IV attenuated the damaging effects of RAW246.7 cell CM on H9c2 cells . Overexpression of Snail1 in M1 macrophages weakened the protective effects of AS-IV on H9c2 cells . In vivo study, results showed that, compared to the MI group, AS-IV treatment reduced lactate levels in the hearts of MI rats, improved cardiac function and myocardial injury and attenuated myocardial cell apoptosis. Conclusion AS-IV inhibits TGF-β pathway activation through the suppression of Snail1 lactylation and acetylation in a macrophage-dependent manner, thereby mitigating myocardial cell damage following MI.
Animals ; Myocardial Infarction/drug therapy* ; Rats ; Snail Family Transcription Factors/metabolism* ; Macrophages/cytology* ; Myocytes, Cardiac/metabolism* ; Triterpenes/pharmacology* ; Saponins/pharmacology* ; Acetylation/drug effects* ; Apoptosis/drug effects* ; Mice ; Cell Line ; RAW 264.7 Cells ; Transforming Growth Factor beta/metabolism*

OBJECTIVES: To investigate the effect of Shenge powder (SGP) on myocardial fibrosis in rats with heart failure after myocardial infarction and its relation with lysyl oxidase like protein 2 (LOXL2)/transforming growth factor-β1 (TGF-β1)/IL-11 signaling pathway. METHODS: Seventy-two SPF male SD rats were divided into blank control group, model control group, SGP small dose group, SGP large dose group, positive control group, SGP large dose+LOXL2 activator group, with 12 rats in each group. Except for the blank control group, post-myocardial infarction heart failure was induced by coronary constriction. Corresponding treatments were given immediately after successful modeling, once a day for 4 weeks. Left ventricular fractional shortening (LVFS) and left ventricular ejection fraction (LVEF) in rats were detected by color Doppler ultrasound imaging. Levels of IL-1β and IL-6 in serum were analyzed by ELISA method. Myocardial collagen volume fraction (CVF) was evaluated by Masson staining. Expressions of collagen Ⅰ and α-smooth muscle actin (α-SMA) in myocardial tissue were detected by immunohistochemical staining. The mRNA expressions of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) in myocardial tissue were detected by qRT-PCR. Expression of LOXL2, TGF-β1, and IL-11 proteins in myocardial tissue were detected by Western blotting. RESULTS: Compared with the blank control group, the LVFS and LVEF of the model control group decreased, the levels of serum IL-6 and IL-1β elevated, and the CVF value, the expressions of collagen Ⅰ and α-SMA in myocardial tissue, MMP-9 and TIMP-1 mRNA, and LOXL2, TGF-β1, IL-11 proteins increased (all P<0.05). Compared with the model control group, the LVFS and LVEF of SGP small dose group, SGP large dose group and positive control group increased, the levels of serum IL-6 and IL-1β decreased, and the CVF value, the expressions of collagen Ⅰ and α-SMA in myocardial tissue, MMP-9 and TIMP-1 mRNA, and LOXL2, TGF-β1, IL-11 proteins decreased (all P<0.05); while LOXL2 activator reversed the improvement effect of high-dose SGP on myocardial fibrosis in heart failure rats after myocardial infarction. CONCLUSIONS Shenge powder may inhibit myocardial fibrosis in heart failure rats after myocardial infarction by inhibiting the LOXL2/TGF-β1/IL-11 pathway.
Animals ; Male ; Rats, Sprague-Dawley ; Myocardial Infarction/complications* ; Transforming Growth Factor beta1/metabolism* ; Signal Transduction/drug effects* ; Drugs, Chinese Herbal/therapeutic use* ; Rats ; Heart Failure/pathology* ; Myocardium/metabolism* ; Fibrosis ; Amino Acid Oxidoreductases/metabolism* ; Interleukin-11/metabolism* ; Tissue Inhibitor of Metalloproteinase-1/metabolism* ; Matrix Metalloproteinase 9/metabolism*

Myocardial infarction is a cardiovascular disease with high morbidity and mortality rates. Hydrogel biomaterials mimicking the extracellular matrix have recently been shown to demonstrate excellent biocompatibility, low immunogenicity, favorable biodegradability, and multifunctionality, showcasing significant potential for treatment of myocardial infarction. Hydrogels can provide mechanical support to the damaged myo-cardium, alleviating pathological remodeling. Moreover, their porous structure makes them ideal carriers for localized and sustained drug delivery. Hydrogels derived from various matrices-including polysaccharides, polypeptides, proteins, decellularized extracellular matrix, and synthetic polymers-exhibit distinct properties in terms of biocompatibility, mechanical performance, and drug delivery capacity. These hydrogels support tissue regeneration and enable targeted release of diverse therapeutics, meeting the various therapeutic demands for myocardial repair. In the infarcted myocardial microenvironment, endogenous signals such as low pH, specific enzyme expression, and elevated levels of reactive oxygen species can trigger responsive drug release from hydrogels, while external physical stimuli-such as ultrasound, light, and magnetic fields-can also be employed to precisely control the release process, thereby enhancing therapeutic efficacy and reducing systemic side effects. This review summarizes recent advances in hydrogel-based drug delivery systems for treatment of myocardial infarction, focusing particularly on the characteristics and advantages of different hydrogel materials for myocardial repair. Furthermore, the responsive drug release behavior of hydrogels is analyzed in the context of the cardiac injury microenvironment, providing a reference for future research.
Hydrogels/chemistry* ; Myocardial Infarction/drug therapy* ; Humans ; Drug Delivery Systems/methods* ; Biocompatible Materials ; Drug Carriers

OBJECTIVE: To evaluate the association between erectile dysfunction (ED) and myocardial infarction (MI) using two sample Mendelian randomization. METHODS: A Mendelian randomization study was conducted using comprehensive data on ED and MI from extensive genome-wide association data. Using inverse variance weighted analysis for causal relationships, and correct for confounding factors using multivariate Mendelian randomization, the potential mediating effects were evaluated as well. Based on Genecard data, the genes related to ED and MI were identified. Molecular docking was used to reveal spontaneously bound drug molecules. RESULTS: Our study found that exposure to ED was a risk factor for MI (OR: 1.001 0, 95% CI: 1.000 2－1.001 8, P=0.017 7), which also held true in the validation dataset (OR: 1.028 5, 95% CI: 1.005 0－1.052 6, P=0.017 2). No statistically significant heterogeneity or horizontal pleiotropy was found. The results of reverse Mendelian randomization analysis showed any reverse causal relationship between ED and MI. In multivariate Mendelian randomization analysis, after excluding confounding factors (excluding triglycerides and high-density lipoprotein), the P-value remained less than 0.05, and the OR ranged from 1.000 1 to 1.000 7, indicating that ED was still a risk factor for MI. In the mediation analysis, it was found that the current mediation ratio of smoking to MI was 13.06%. In summary-data-based mendelian randomization analysis, it was found that the gene PTPN11 was a common target gene for MI and ED (OR=0.990, P<0.001). Subsequent molecular docking with sildenafil, clopidogrel, and dapoxetine could spontaneously bind to the PTPN11 gene receptor. CONCLUSION There is a causal relationship between ED and MI, with smoking as a potential mediating factor, and the gene PTPN11 being a co-target gene.
Humans ; Male ; Mendelian Randomization Analysis ; Myocardial Infarction/genetics* ; Erectile Dysfunction/complications* ; Risk Factors ; Genome-Wide Association Study ; Molecular Docking Simulation ; Polymorphism, Single Nucleotide

OBJECTIVE: To study incident and clinical characteristics of the coronary microcirculation dysfunction (CMD) in patients with acute myocardial infarction (AMI) after percutaneous coronary intervention (PCI) by myocardial contrast echocardiography (MCE) and to explore the predictive value of CMD for in-hospital acute heart failure event. METHODS: One hundred and forty five patients with AMI who had received PCI and completed MCE during hospitalization in Peking University People' s Hospital from November 2015 to July 2021 were enrolled in our study. The patients were divided into CMD group and normal group according to the coronary microcirculation status detected by MCE. Clinical data and MCE data of the two groups were collected and analyzed. The acute heart failure event during hospitalization was described. A multivariate Logistic regression model was built to analyze the risk of acute heart failure in patients with CMD. A receiver operating characteristic (ROC) curve was drawn to evaluate the value of CMD in predicting acute heart failure event. RESULTS: CMD detected by MCE occurred in 87 patients (60%). Compared with normal group, patients with CMD had higher troponin I (TnI) peak level [52.8 (8.1, 84.0) μg/L vs. 18.9 (5.7, 56.1) μg/L, P=0.005], poorer Killip grade on admission (P=0.030), different culprit vessel (P < 0.001) and more patients had thrombolysis in myocardial infarction (TIMI) flow pre-PCI less than grade 3 in culprit vessel (65.1% vs. 43.1%, P=0.025). Meanwhile, patients with CMD had poorer left ventricular ejection fraction (LVEF) [52% (43%, 58%) vs. 61% (54%, 66%)], poorer global longitudinal strain (GLS) [-11.2% (-8.7%, -14.0%) vs.-13.9% (-10.8%, -17.0%)] and worse wall motion score index (WMSI) (1.58±0.36 vs. 1.25± 0.24) (P all < 0.001). Acute left heart failure happened in 13.8% of the CMD patients, which were significant higher than that in the patients with normal coronary microcirculation perfusion (1.7%, P=0.013). After correcting for the culprit vessel, the TIMI flow pre-PCI in the culprit vessel and the peak TnI value, the risk of acute left heart failure in the patients with CMD was still high (OR=9.120, 95%CI: 1.152-72.192, P=0.036). The area under ROC curve (AUC) was 0.677 (95%CI: 0.551-0.804, P=0.035). CONCLUSION The incidence of CMD detected by MCE in patients with AMI post-PCI was 60%. Patients with CMD have a higher risk of acute left heart failure during hospitalization.
Humans ; Heart Failure/physiopathology* ; Microcirculation ; Percutaneous Coronary Intervention/adverse effects* ; Myocardial Infarction/complications* ; Male ; Female ; Hospitalization ; Middle Aged ; Aged ; Echocardiography ; Coronary Circulation ; Predictive Value of Tests ; Troponin I/blood*