Impact of augmented renal clearance on anticoagulant therapy in critically ill patients with coronavirus disease 2019: A retrospective cohort study.

INTRODUCTION: This study aimed to determine the impact of augmented renal clearance (ARC) on anticoagulation therapy in critically ill patients with coronavirus disease 2019 (COVID-19). METHODS: This retrospective cohort study included adult patients with severe COVID-19 with ARC who had been treated at our hospital between 2020 and 2021. We measured the estimated glomerular filtration rate calculated by the Chronic Kidney Disease Epidemiology Collaboration formula (eGFRCKD-EPI) every morning, and ARC condition was defined as eGFRCKD-EPI ≥ 130 mL/min/1.73 m2. Multivariate regression analysis with Huber-White sandwich estimator was performed to examine the association of unfractionated heparin (UH) dosage between blood test timings with activated partial thromboplastin time (APTT) compared with and without ARC. RESULTS: We identified 38 enrolled patients: seven and 31 in the ARC and non-ARC groups, respectively. In the ARC coexisting condition, a higher dose of UH, which corresponded to the total dose in 24 h from the previous day, was required to achieve the same APTT prolongation, with a significant difference (p < 0.001). CONCLUSIONS: Our study suggests that careful monitoring and consideration of higher UH doses in critically ill patients with COVID-19 is necessary because anticoagulation failure can occur during ARC.

Synergy by Ristocetin and CXCL12 in Human Platelet Activation: Divergent Regulation by Rho/Rho-Kinase and Rac.

CXCL12, belonging to the CXC chemokine family, is a weak agonist of platelet aggregation. We previously reported that the combination of CXCL12 and collagen at low doses synergistically activates platelets via not CXCR7 but CXCR4, a specific receptor for CXCL12 on the plasma membrane. Recently, we reported that not Rho/Rho kinase, but Rac is involved in the platelet aggregation induced by this combination. Ristocetin is an activator of the von Willebrand factor that interacts with glycoprotein (GP) Ib/IX/V, which generates thromboxane A2 via phospholipase A2 activation, resulting in the release of the soluble CD40 ligand (sCD40L) from human platelets. In the present study, we investigated the effects of a combination of ristocetin and CXCL12 at low doses on human platelet activation and its underlying mechanisms. Simultaneous stimulation with ristocetin and CXCL12 at subthreshold doses synergistically induce platelet aggregation. A monoclonal antibody against not CXCR7 but CXCR4 suppressed platelet aggregation induced by the combination of ristocetin and CXCL12 at low doses. This combination induces a transient increase in the levels of both GTP-binding Rho and Rac, followed by an increase in phosphorylated cofilin. The ristocetin and CXCL12-induced platelet aggregation as well as the sCD40L release were remarkably enhanced by Y27362, an inhibitor of Rho-kinase, but reduced by NSC23766, an inhibitor of the Rac-guanine nucleotide exchange factor interaction. These results strongly suggest that the combination of ristocetin and CXCL12 at low doses synergistically induces human platelet activation via Rac and that this activation is negatively regulated by the simultaneous activation of Rho/Rho-kinase.

Recombinant Antithrombin Attenuates Acute Respiratory Distress Syndrome in Experimental Endotoxemia.

Sepsis-induced endothelial acute respiratory distress syndrome is related to microvascular endothelial dysfunction caused by endothelial glycocalyx disruption. Recently, recombinant antithrombin (rAT) was reported to protect the endothelial glycocalyx from septic vasculitis; however, the underlying mechanism remains unknown. Here, we investigated the effect of rAT administration on vascular endothelial injury under endotoxemia. Lipopolysaccharide (LPS; 20 mg/kg) was injected intraperitoneally into 10-week-old male C57BL/6 mice, and saline or rAT was administered intraperitoneally at 3 and 24 hours after LPS administration. Subsequently, serum and/or pulmonary tissues were examined for inflammation and cell proliferation and differentiation by histologic, ultrastructural, and microarray analyses. The survival rate was significantly higher in rAT-treated mice than in control mice 48 hours after LPS injection (75% versus 20%; P < 0.05). Serum interleukin-1ß was increased but to a lesser extent in response to LPS injection in rAT-treated mice than in control mice. Lectin staining and ultrastructural studies showed a notable attenuation of injury to the endothelial glycocalyx after rAT treatment. Microarray analysis further showed an up-regulation of gene sets corresponding to DNA repair, such as genes involved in DNA helicase activity, regulation of telomere maintenance, DNA-dependent ATPase activity, and ciliary plasm, after rAT treatment. Thus, rAT treatment may promote DNA repair, attenuate inflammation, and promote ciliogenesis, thereby attenuating the acute respiratory distress syndrome caused by endothelial injury.

Amyloid ß protein negatively regulates human platelet activation induced by thrombin receptor-activating protein.

Amyloid ß protein deposition in cerebral vessels, a characteristic of Alzheimer's disease, is a risk factor for intracerebral hemorrhage. Amyloid ß protein directly modulates human platelet function; however, the exact mechanism of action is unclear. Therefore, we investigated the effects of amyloid ß protein on human platelet activation using an aggregometer with laser scattering. Amyloid ß protein decreased platelet aggregation induced by thrombin receptor-activating protein, but not by collagen and ADP. Amyloid ß protein also suppressed platelet aggregation induced by SCP0237 and A3227. Platelet-derived growth factor-AB secretion and phosphorylated-heat shock protein 27 release by thrombin receptor-activating protein were inhibited by amyloid ß protein. Additionally, thrombin receptor-activating protein-induced phosphorylation of JNK and p38 MAP kinase was reduced by amyloid ß protein. Collectively, our results strongly suggest that amyloid ß protein negatively regulates protease-activated receptor-elicited human platelet activation. These findings may indicate a cause of intracerebral hemorrhage due to amyloid ß protein.

Relationship between the Responsiveness of Amyloid ß Protein to Platelet Activation by TRAP Stimulation and Brain Atrophy in Patients with Diabetes Mellitus.

Type 2 DM is a risk factor for dementia, including Alzheimer's disease (AD), and is associated with brain atrophy. Amyloid ß protein (Aß) deposition in the brain parenchyma is implicated in the neurodegeneration that occurs in AD. Platelets, known as abundant storage of Aß, are recognized to play important roles in the onset and progression of AD. We recently showed that Aß negatively regulates platelet activation induced by thrombin receptor-activating protein (TRAP) in healthy people. In the present study, we investigated the effects of Aß on the TRAP-stimulated platelet activation in DM patients, and the relationship between the individual responsiveness to Aß and quantitative findings of MRI, the volume of white matter hyperintensity (WMH)/intracranial volume (IC) and the volume of parenchyma (PAR)/IC. In some DM patients, Aß reduced platelet aggregation induced by TRAP, while in others it was unchanged or rather enhanced. The TRAP-induced levels of phosphorylated-Akt and phosphorylated-HSP27, the levels of PDGF-AB and the released phosphorylated-HSP27 correlated with the degree of platelet aggregability. The individual levels of not WMH/IC but PAR/IC was correlated with those of TRAP-stimulated PDGF-AB release. Collectively, our results suggest that the reactivity of TRAP-stimulated platelet activation to Aß differs in DM patients from healthy people. The anti-suppressive feature of platelet activation to Aß might be protective for brain atrophy in DM patients.

Olive polyphenol reduces the collagen-elicited release of phosphorylated HSP27 from human platelets.

Hydroxytyrosol (HT) and oleuropein (OLE) are natural polyphenols found in extra virgin olive oil. Accumulating evidence indicates that ingestion of olive oil contributes to reduce the risk of cardiovascular diseases and stroke. It has been reported that HT and OLE inhibit human platelet aggregation. We have shown that collagen induces the phosphorylation of heat shock protein 27 (HSP27) in human platelets, resulting in the release of HSP27, an extracellular pro-inflammatory agent. In this study, we investigated the effects of HT and OLE on the collagen-stimulated human platelet activation. The PDGF-AB secretion and the soluble CD40 ligand (sCD40L) release by collagen were reduced by HT or OLE. HT and OLE significantly suppressed the phosphorylation of HSP27 and the release of phosphorylated-HSP27. These findings suggest that olive polyphenol reduces the collagen-stimulated phosphorylation of HSP27 in human platelets and the release. Our results may provide a novel anti- inflammatory effect of olive polyphenol.

Rac Regulates the TRAP-Induced Release of Phosphorylated-HSP27 from Human Platelets via p38 MAP Kinase but Not JNK.

BACKGROUND/AIMS: Thrombin induces the activation of human platelets through protease-activated receptor (PAR) 1 and PAR4, and Rac, a member of the Rho family of small GTPases, is implicated in PAR activation. We previously reported that phosphorylated-heat shock protein 27 (HSP27) is released from the thrombin receptor-activating peptide (TRAP)-stimulated platelets of diabetic patients. In the present study, we investigated the role of Rac in the TRAP-elicited release of phosphorylated-HSP27 from human platelets. METHODS: Platelet aggregation was measured using an aggregometer with laser scattering. Protein phosphorylation was analyzed by Western blotting. The levels of phosphorylated-HSP27 and platelet-derived growth factor-AB (PDGF-AB) were measured by enzyme-linked immunosorbent assays. RESULTS: NSC23766, an inhibitor of Rac-guanine nucleotide exchange factor interaction, suppressed the TRAP-elicited release of phosphorylated-HSP27 as well as platelet aggregation. The TRAP-induced phosphorylation of HSP27, p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) was attenuated by NSC23766. SB203580, a p38 MAPK inhibitor, but not SP600125, a JNK inhibitor, suppressed the release of phosphorylated-HSP27 in addition to HSP27 phosphorylation. On the other hand, both SB203580 and SP600125 reduced the TRAP-stimulated secretion of PDGF-AB. CONCLUSION: Our results strongly suggest that Rac acts as a positive regulator of the PAR-elicited release of phosphorylated-HSP27 from human platelets via p38 MAPK but not JNK.

Three-dimensional ultrastructure of capillary endothelial glycocalyx under normal and experimental endotoxemic conditions.

BACKGROUND: Sugar-protein glycocalyx coats healthy endothelium, but its ultrastructure is not well described. Our aim was to determine the three-dimensional ultrastructure of capillary endothelial glycocalyx in the heart, kidney, and liver, where capillaries are, respectively, continuous, fenestrated, and sinusoidal. METHODS: Tissue samples were processed with lanthanum-containing alkaline fixative, which preserves the structure of glycocalyx. RESULTS: Scanning and transmission electron microscopy revealed that the endothelial glycocalyx layer in continuous and fenestrated capillaries was substantially thicker than in sinusoids. In the heart, the endothelial glycocalyx presented as moss- or broccoli-like and covered the entire luminal endothelial cell surface. In the kidney, the glycocalyx appeared to nearly occlude the endothelial pores of the fenestrated capillaries and was also present on the surface of the renal podocytes. In sinusoids of the liver, glycocalyx covered not only the luminal side but also the opposite side, facing the space of Disse. In a mouse lipopolysaccharide-induced experimental endotoxemia model, the capillary endothelial glycocalyx was severely disrupted; that is, it appeared to be peeling off the cells and clumping. Serum concentrations of syndecan-1, a marker of glycocalyx damage, were significantly increased 24 h after administration of lipopolysaccharide. CONCLUSIONS: In the present study, we visualized the three-dimensional ultrastructure of endothelial glycocalyx in healthy continuous, fenestrated, and sinusoidal capillaries, and we also showed their disruption under experimental endotoxemic conditions. The latter may provide a morphological basis for the microvascular endothelial dysfunction associated with septic injury to organs.

Hyperbaric oxygenation therapy for crush injuries reduces the risk of complications: research report.

BACKGROUND: Hyperbaric oxygen (HBO2) therapy has been adopted for crush injuries, but there are few studies supporting its use. We therefore investigated the effects of HBO2 on management of patients with complicated crush injuries. METHODS: This historic cohort study included patients with crush injuries and open fractures with severities greater than or equal to Gustilo class IIIA. We divided the patients into two groups: Control and HBO2. The control group received conventional treatment, while the HBO2 group received conventional treatment plus HBO2. We compared the groups with respect to the incidence of infection, need for additional surgery, and length of intensive care unit (ICU) and hospital stays. RESULTS: There were 16 patients in the HBO2 group and 13 in the control group. There were no patients with infections in the HBO2 group, whereas in the control group six patients had infections and five needed another drainage procedure. These incidences were significantly lower in the HBO2 group (p = 0.003 and 0.013). However, the durations of ICU and hospital stays were similar across the two groups. CONCLUSIONS: HBO2 is effective in the management of crush injuries from the viewpoint of reducing complications and reoperations. These observations should be verified in additional studies with larger sample sizes because the patient number is limited.

Inverse relationship between platelet Akt activity and hippocampal atrophy: A pilot case-control study in patients with diabetes mellitus.

BACKGROUND: Akt plays diverse roles in humans. It is involved in the pathogenesis of type 2 diabetes mellitus (T2DM), which is caused by insulin resistance. Akt also plays a vital role in human platelet activation. Furthermore, the hippocampus is closely associated with memory and learning, and a decrease in hippocampal volume is reportedly associated with an insulin-resistant phenotype in T2DM patients without dementia. AIM: To investigate the relationship between Akt phosphorylation in unstimulated platelets and the hippocampal volume in T2DM patients. METHODS: Platelet-rich plasma (PRP) was prepared from the venous blood of patients with T2DM or age-matched controls. The pellet lysate of the centrifuged PRP was subjected to western blotting to analyse the phosphorylation of Akt, p38 mitogen-activated protein (MAP) kinase and glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Phosphorylation levels were quantified by densitometric analysis. Hippocampal volume was analysed using a voxel-based specific regional analysis system for Alzheimer's disease on magnetic resonance imaging, which proposes the Z-score as a parameter that reflects hippocampal volume. RESULTS: The levels of phosphorylated Akt corrected with phosphorylated p38 MAP kinase were inversely correlated with the Z-scores in the T2DM subjects, whereas the levels of phosphorylated Akt corrected with GAPDH were not. However, this relationship was not observed in the control patients. CONCLUSION: These results suggest that an inverse relationship may exist between platelet Akt activation and hippocampal atrophy in T2DM patients. Our findings provide insight into the molecular mechanisms underlying T2DM hippocampal atrophy.

Spinal injury with spinal ankylosing disorders as a primary cause of death: report of two cases.

BACKGROUND: Spinal ankylosing disorders (SADs) refer to a group of conditions resulting in spontaneous or postsurgical ossification and fusion of the spinal segments. The spine becomes increasingly susceptible to injury over time such that even low-energy trauma can cause a spinal injury. We report two cases of SADs, associated with massive thoracic hemorrhage. CASE PRESENTATION: The first patient was an 85-year-old male, who suffered from a vehicular crash. He was diagnosed with a fracture of the first lumbar vertebra, accompanied by SADs. Intubation was required, and thoracic drainage tubes were inserted. The patient underwent a massive transfusion and thoracotomy with packing. Despite prompt treatment, the hemorrhage from the vertebral fracture was uncontrolled, and the patient died 180 min after the injury. The second case features an 88-year-old male who fell from a height. He was diagnosed with flail chest, hemothorax, pneumothorax, and a fracture of the eighth thoracic vertebra with SADs. After intubation, four thoracic drainage tubes were placed, and a massive transfusion was conducted. He died after 3 days due to hypoxemia secondary to persistent bleeding of the vertebral fracture for 24 h. CONCLUSIONS: The patients died of persistent thoracic hemorrhage, and the sources of bleeding were the fracture site of the spine fractures. Controlling spinal hemorrhage is difficult due to the absence of a bleeding artery, which is managed via trans-arterial embolization. This report emphasized that fracture of SADs could be a fatal disease that requires prompt intervention.

Serum syndecan-1 concentration in hemolysis, elevated liver enzymes, and low platelets syndrome: A case report.

Background: Hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome occurs in pregnant and postpartum individuals. We observed serum syndecan-1 (SDC-1) levels, which is a component of the glycocalyx, in a patient with HELLP syndrome from admission to the postpartum period and examined their association as reflecting the pathophysiology related to endothelial injury. Case presentation: A 31-year-old primiparous female patient without a previous medical history at a gestational age of 37 weeks and 6 days was transferred to our hospital the morning after a visit to a previous hospital with headache and nausea. Elevated transaminase, platelet count, and proteinuria were noted. Head magnetic resonance imaging revealed a caudate nucleus hemorrhage and posterior reversible encephalopathy syndrome. After she delivered her newborn through an emergency cesarean section, she was admitted to the intensive care unit. On day 4 post-delivery, the patient's D-dimer concentration was elevated, and contrast-enhanced computed tomography was performed. The results indicated pulmonary embolism, and heparin administration was initiated. The serum SDC-1 level was highest on day 1 post-delivery and quickly decreased subsequently; however, it remained elevated during the postpartum period. Her condition gradually improved, and she was extubated on day 6 and discharged from the ICU on day 7 post-delivery. Conclusion: We measured SDC-1 concentration in a patient with HELLP syndrome and found that the clinical course correlated with SDC-1 levels, indicating that SDC-1 is elevated immediately before and after pregnancy termination in patients with HELLP syndrome. Therefore, SDC-1 fluctuations, combined with the elevation of the D-dimer level, may be a potential marker for the early detection of HELLP syndrome and estimation of the syndrome's severity in the future.

Atypical drug-induced hypersensitivity syndrome with multiple organ failure rescued by combined acute blood purification therapy: a case report.

BACKGROUND: Drug-induced hypersensitivity syndrome (DIHS), including Stevens-Johnson syndrome (SJS), is a severe rash that often develops 2-6 weeks after the intake of the causative drug; however, its diagnosis is sometimes difficult. This article describes a case in which a patient with DIHS-induced multiple organ failure was successfully treated with blood purification therapy. CASE PRESENTATION: A male patient in his 60s was admitted to our hospital with autoimmune encephalitis. The patient was treated with steroid pulse therapy, acyclovir, levetiracetam, and phenytoin. From the 25th day, he presented with fever (≥ 38 °C) as well as miliary-sized erythema on the extremities and trunk, followed by erosions. DIHS and SJS were suspected; accordingly, levetiracetam, phenytoin, and acyclovir were discontinued. On the 30th day, his condition further deteriorated, and he was admitted to the intensive care unit for ventilatory management. The next day, he developed multi-organ failure and was started on hemodiafiltration (HDF) for acute kidney injury. Although he presented with hepatic dysfunction and the appearance of atypical lymphocytes, he did not meet the diagnostic criteria for DIHS or SJS/toxic epidermal necrolysis. Therefore, he was diagnosed with multi-organ failure caused by severe drug eruption and underwent a 3-day treatment with plasma exchange (PE) in addition to HDF. Accordingly, the patient was diagnosed with atypical DIHS. After being started on blood purification therapy, the skin rash began to disappear; moreover, the organ damage improved, with a gradual increase in urine output. Eventually, the patient was weaned off the ventilator and transferred to the hospital on the 101st day. CONCLUSIONS: HDF + PE could effectively treat multi-organ failure caused by atypical DIHS, which is difficult to diagnose.

Tramadol regulates the activation of human platelets via Rac but not Rho/Rho-kinase.

Tramadol is a useful analgesic which acts as a serotonin and noradrenaline reuptake inhibitor in addition to µ-opioid receptor agonist. Cytoplasmic serotonin modulates the small GTPase activity through serotonylation, which is closely related to the human platelet activation. We recently reported that the combination of subthreshold collagen and CXCL12 synergistically activates human platelets. We herein investigated the effect and the mechanism of tramadol on the synergistic effect. Tramadol attenuated the synergistically stimulated platelet aggregation (300 µM of tramadol, 64.3% decrease, p<0.05). Not morphine or reboxetine, but duloxetine, fluvoxamine and sertraline attenuated the synergistic effect of the combination on the platelet aggregation (30 µM of fluvoxamine, 67.3% decrease, p<0.05; 30 µM of sertraline, 67.8% decrease, p<0.05). The geranylgeranyltransferase inhibitor GGTI-286 attenuated the aggregation of synergistically stimulated platelet (50 µM of GGTI-286, 80.8% decrease, p<0.05), in which GTP-binding Rac was increased. The Rac1-GEF interaction inhibitor NSC23766 suppressed the platelet activation and the phosphorylation of p38 MAPK and HSP27 induced by the combination of collagen and CXCL12. Tramadol and fluvoxamine almost completely attenuated the levels of GTP-binding Rac and the phosphorylation of both p38 MAPK and HSP27 stimulated by the combination. Suppression of the platelet aggregation after the duloxetine administration was observed in 2 of 5 patients in pain clinic. These results suggest that tramadol negatively regulates the combination of subthreshold collagen and CXCL12-induced platelet activation via Rac upstream of p38 MAPK.

Clinical characteristics of patients with snow sports trauma transported to a trauma care center: A retrospective observational study.

BACKGROUND: Snow sports are a popular recreational activity; however, the incidence of injury of snow sports can be high for skiers and snowboarders. Our hospital receives severe trauma cases from snow resorts and hospitals throughout the region. This study aimed to determine whether the risk of snow sports-related major trauma that requires emergency surgery under general anesthesia varies by the equipment and injury mechanism. METHODS: This retrospective cohort study included patients with snow sports trauma referred to Gifu University Hospital, Japan between November 2010 and March 2020. We analyzed the need for emergency operation under general anesthesia within 24 h using Fisher's exact test. We identified 106 patients: (1) 90 in the snowboarders' group and 16 in the skiers' group or (2) 46 in the fall after jumping group (jumping group), 27 in the collide with other people and obstacle group (collision group), and 33 in the fall during gliding group (gliding group). RESULTS: Snowboarders were nearly twice as likely as skiers to require emergency surgery under general anesthesia (44% vs. 25%; p = 0.236]. No significant associations were found between emergency surgery under general anesthesia and injury mechanism, but half of the patients in the jumping group required emergency surgery. CONCLUSIONS: Snowboard as equipment and falls after jumping as a mechanism of injury tended to be associated with emergency surgery under general anesthesia, with no significant differences. In order to provide adequate resources for snow sports trauma, the cause of the patient's injury is strongly related to the urgency of the condition, and transport to a trauma center should be actively considered. Further studies are warranted with respect to the effects of personal protective equipment and skill level.

Corrigendum: Retrospective cohort study to determine the effect of preinjury antiplatelet or anticoagulant therapy on mortality in patients with major trauma.

[This corrects the article DOI: 10.3389/fmed.2022.1089219.].

Oncostatin M reduces the synthesis of macrophage-colony stimulating factor stimulated by TGF-ß via suppression of p44/p42 MAP kinase and JNK in osteoblasts.

Bone fracture is an important trauma frequently encountered into emergency medicine as well as orthopedics reflecting an aging society. Oncostatin M, an inflammatory cytokine produced by osteal macrophages, has been considered to play a crucial role in fracture healing. Macrophage colony-stimulating factor (M-CSF) secreted from osteoblasts is essential in osteoclastgenesis, and the secretion is stimulated by transforming growth factor-ß (TGF-ß). The aim of this study is to elucidate the effects of oncostatin M on the TGF-ß-induced M-CSF synthesis in osteoblast-like MC3T3-E1 cells and the underlying mechanisms. Oncostatin M attenuated the TGF-ß-stimulated M-CSF release and the mRNA expressions. SMAD3 inhibitor SIS3, p38 MAP kinase inhibitor SB203580, MEK1/2 inhibitor PD98059, and SAPK/JNK inhibitor SP600125 significantly suppressed the M-CSF release. Oncostatin M suppressed the TGF-ß-induced phosphorylation of p44/p42 MAP kinase and SAPK/JNK, but failed to affect the phosphorylation of SMAD3 and p38 MAP kinase. Oncostatin M attenuated the TGF-ß-stimulated vascular endothelial growth factor (VEGF) release and the TGF-ß-induced mRNA expressions of VEGF. These results strongly suggest that oncostatin M downregulates TGF-ß signaling upstream of p44/p42 MAP kinase and SAPK/JNK, but not SMAD 2/3 and p38 MAP kinase, in osteoblasts, leading to the attenuation of M-CSF synthesis. Our findings might provide a new therapeutic strategy for the acceleration of fracture healing process.

Thrombopoietin and collagen in low doses cooperatively induce human platelet activation.

Aim: In acute medicine, we occasionally treat life-threatening conditions such as sepsis and trauma, which cause severe thrombocytopenia. Serum thrombopoietin levels have been reported to increase under the condition of thrombocytopenia related to severity. Collagen is a crucial activator of platelets, and Rho family members, such as Rho/Rho-kinase and Rac, play roles as active molecules involved in the intracellular signaling pathways in platelet activation. The present study aimed to elucidate the effects of thrombopoietin (TPO) on subthreshold low-dose collagen-stimulated human platelets in terms of Rho/Rho-kinase and Rac. Methods: Platelet-rich plasma donated from healthy volunteers was stimulated by the subthreshold low-dose of collagen after pretreatment with TPO and/or NSC23766, an inhibitor of the Rac-guanine nucleotide exchange factor interaction, or Y27632, an inhibitor of Rho-kinase. Platelet aggregation was measured using an aggregometer based on laser-scattering methods. Proteins involved in intracellular signaling were analyzed using western blotting, and the secretion of platelet-derived growth factor-AB from activated platelets was determined using an enzyme-linked immunosorbent assay. Results: Under the existence of TPO, the low dose of collagen remarkably elicited the aggregation and platelet-derived growth factor-AB secretion of platelets, which were suppressed by NSC23766 and Y27632. The combination of TPO and collagen considerably induced a transient increase of guanosine triphosphate (GTP)-binding Rac and GTP-binding Rho followed by an increase of phosphorylated cofilin, a Rho-kinase substrate. Conclusion: These results strongly suggest that TPO and collagen in low doses cooperatively potentiate human platelet activation through both Rac and Rho/Rho-kinase mediated pathways.

Leriche syndrome diagnosed due to polytrauma: a case report.

BACKGROUND: Leriche syndrome is caused by atherosclerosis and is often characterized by symptoms such as intermittent claudication and numbness and coldness of the lower limbs. Its exact prevalence and incidence are unknown because it is a rare disease. We report a case of Leriche syndrome diagnosed incidentally on trauma pan-scan computed tomography (CT). CASE PRESENTATION: A 61-year-old Asian male was driving a passenger car and had a head-on collision with a dump truck that required an emergency call. The patient was transported to our hospital in a doctor's helicopter. Physical examination revealed the following vital signs: respiratory rate, 23 breaths per min; SpO2, 98% under a 10-L administration mask; pulse rate, 133 beats per min; blood pressure, 142/128 mmHg; Focused Assessment with Sonography for Trauma, positive; Glasgow Coma Scale assessment, E3V5M6; and body temperature, 35.9 °C. Trauma pan-scan CT showed bilateral mandibular fractures, bilateral multiple rib fractures, bilateral pneumothorax, sternal fractures, hematoma around thoracic spine, small bowel perforation, mesenteric injury, right clavicle fracture, right ankle debridement injury, and thrombotic occlusion from just above the abdominal aortic bifurcation to the bilateral common iliac arteries. Although thrombotic occlusion needed to be differentiated from traumatic aortic injury, the presence of collateral blood vessels led to the diagnosis of Leriche syndrome, and conservative treatment was performed. Damage control surgery was required for the small bowel injuries. From the second day of admission, the patient was treated with continuous intravenous heparin and prostaglandin preparations. However, impaired blood flow and reperfusion injury in the right lower extremity progressed. On the fifth day of admission, right thigh amputation was performed. The patient required renal replacement therapy for 2 weeks starting from the third day of admission. CONCLUSIONS: In this case, conservative therapy was initially chosen for Leriche syndrome. However, the complex factors in the acute phase of trauma led to development of hemorrhagic necrosis, requiring amputation of the lower extremity. Our findings indicate the need to carefully consider the unique factors affecting Leriche syndrome patients when considering treatment indications and choices for trauma.

Hypergranulation over a meshed split-thickness skin graft, a complication of negative-pressure wound therapy: a case report.

BACKGROUND: We present a case of a rare complication of negative-pressure wound therapy (NPWT) wherein there was fixation of a meshed split-thickness skin graft (STSG), suspected as a failure by hypergranulation. However, the meshed STSG was integrated within 5 days of NPWT cessation. CASE PRESENTATION: A 22-year-old Asian man sustained 25% total-body-surface-area flame burns. After multiple operations, an ulcer was present on the proximal left thigh. On day 37 after admission, the ulcer was debrided, and an 11/1000-inch (0.28 mm) skin graft was taken from the ipsilateral thigh and meshed, using a 1:1.5 ratio. NPWT was applied to the donor and recipient sites with a continuous negative pressure of 125 mmHg. On day 43, NPWT was discontinued. The skin grafts were not identified on the surface of the granulation tissue. With topical ointment therapy, rapid epithelialization of the ulcer was observed as the granulation tissue regressed. On day 48, the recipient site had completely epithelialized. CONCLUSIONS: The hypergranulation tissue rarely covered the meshed STSGs when the grafts were fixed by NPWT. In that case, immediate debridement should be avoided, and conservative treatment should be initiated.