Nonlethal Molecular Nanomachines Potentiate Antibiotic Activity Against Gram-Negative Bacteria by Increasing Cell Permeability and Attenuating Efflux.

Antibiotic resistance is a pressing public health threat. Despite rising resistance, antibiotic development, especially for Gram-negative bacteria, has stagnated. As the traditional antibiotic research and development pipeline struggles to address this growing concern, alternative solutions become imperative. Synthetic molecular nanomachines (MNMs) are molecular structures that rotate unidirectionally in a controlled manner in response to a stimulus, such as light, resulting in a mechanical action that can propel molecules to drill into cell membranes, causing rapid cell death. Due to their broad destructive capabilities, clinical translation of MNMs remains challenging. Hence, here, we explore the ability of nonlethal visible-light-activated MNMs to potentiate conventional antibiotics against Gram-negative bacteria. Nonlethal MNMs enhanced the antibacterial activity of various classes of conventional antibiotics against Gram-negative bacteria, including those typically effective only against Gram-positive strains, reducing the antibiotic concentration required for bactericidal action. Our study also revealed that MNMs bind to the negatively charged phospholipids of the bacterial inner membrane, leading to permeabilization of the cell envelope and impairment of efflux pump activity following light activation of MNMs. The combined effects of MNMs on membrane permeability and efflux pumps resulted in increased antibiotic accumulation inside the cell, reversing antibiotic resistance and attenuating its development. These results identify nonlethal MNMs as pleiotropic antibiotic enhancers or adjuvants. The combination of MNMs with traditional antibiotics is a promising strategy against multidrug-resistant Gram-negative infections. This approach can reduce the amount of antibiotics needed and slow down antibiotic resistance development, thereby preserving the effectiveness of our current antibiotics.

[Antagonistic Effect and Mechanism of Nano Titanium Dioxide and Cadmium on the Growth of Scenedesmus obliquus].

The release of manufactured nanomaterials (MNMs) into the environment has raised concerns about combined toxicological risks, as MNMs could significantly alter the environmental behavior and fate of co-existing contaminants. Numerous studies have been published on the combined toxicity of MNMs and co-existing contaminants, but the potential mechanisms controlling the combined toxicity, especially the biological response mechanism, remain unclear. This study investigated the combined toxicity of nano-titanium dioxide (nTiO2), a typical MNM, and the heavy metal cadmium (Cd2+), using Scenedesmus obliquus as the test organism. The molecular mechanism was examined under different concentrations, using an equivalent dose (toxic ratio 1 ∶1) on S. obliquus. The results showed that the 72h-EC50 of nTiO2 and Cd2+ at the equivalent dose was significantly higher than that of single exposure, indicating an antagonistic effect. Further transcriptomics analysis revealed that the photosynthesis, chlorophyll metabolism, and starch and sucrose metabolism pathways involved in the energy metabolism of S. obliquus were significantly up-regulated in the presence of nTiO2. The arginine and proline metabolic pathways related to the anti-stress effect of algae cells also showed positive stimulation. The results of this study provide an important reference and a research basis for in-depth understanding of the environmental effects of MNMs and co-existing contaminants.

Nanopesticides: Physico-chemical characterization by a combination of advanced analytical techniques.

The recent application of manufactured nanomaterials (MNMs) in plant protection products (PPPs) enhances stability of the active substance (a.s.), minimizes application losses, reduces the quantities of a.s., increases coverage on leaf surface, improves precise application, etc. Besides offering benefits, there is high concern about the potential risk for human and environment associated with the use of nanopesticides. In this study, a panel of complementary methodologies were used to determine size distribution and chemical identification of four different formulations of nanopesticides. Measurements were performed by dynamic light scattering (DLS), transmission electron microscopy (TEM), asymmetric field flow fractionation-multi angle light scattering (AF4-FFF-MALS), gas/liquid chromatography with mass spectrometry (GC-MS/MS, LC-MS/MS) or diode array detector (HPLC-DAD) and inductively coupled plasma mass spectrometry (ICP-MS). Results indicated average size values in the ranges: 27.4-148.7 nm by DLS; 39.1-82.0 nm by AF4-FFF-MALS; and 42-90 nm by TEM. Linked to these nanosized particles both organic active ingredients and inorganic ones were identified. In addition, the obtained data revealed that all the four PPPs contained more than 50% of particles with number size distribution between 1 and 100 nm and, according to the European Commission definition, they can be defined as nanopesticides.

Biofriendly micro/nanomotors operating on biocatalysis: from natural to biological environments.

Micro/nanomotors (MNMs) are tiny motorized objects that can autonomously navigate in complex fluidic environments under the influence of an appropriate source of energy. Internal energy driven MNMs are composed of certain reactive materials that are capable of converting chemical energy from the surroundings into kinetic energy. Recent advances in smart nanomaterials design and processing have endowed the internal energy driven MNMs with different geometrical designs and various mechanisms of locomotion, with remarkable travelling speed in diverse environments ranging from environmental water to complex body fluids. Among the different design principals, MNM systems that operate from biocatalysis possess biofriendly components, efficient energy conversion, and mild working condition, exhibiting a potential of stepping out of the proof-of-concept phase for addressing many real-life environmental and biotechnological challenges. The biofriendliness of MNMs should not only be considered for in vivo drug delivery but also for environmental remediation and chemical sensing that only environmentally friendly intermediates and degraded products are generated. This review aims to provide an overview of the recent advances in biofriendly MNM design using biocatalysis as the predominant driving force, towards practical applications in biotechnology and environmental technology.

Pretreatment with the Free Radical Scavenger Edaravone Mitigates Kidney Glycogen Depletion and Neutrophil Infiltration after Leg Ischemia in a Rat Model: A Pilot Study.

Objective: We have previously shown that pretreatment with the free radical scavenger edaravone (Radicut®, Mitsubishi Tanabe Pharma Co., Japan) mitigated skeletal muscle damage due to ischemia reperfusion. In this study, we sought to validate its use in an experimental model of myonephropathic-metabolic syndrome (MNMS). Methods: Either edaravone (3.0 mg/kg; edaravone group; n=4) or saline (saline group; n=6) was intraperitoneally injected into male Lewis rats (508±31 g). Normal kidneys were harvested as control (n=3). MNMS was induced by bilaterally clamping the common femoral arteries for 5 h and declamping 5 h later. Kidney damage was evaluated by quantifying Periodic Acid Schiff (PAS)-positive area (glycogen storage) and esterase-positive cells (neutrophil infiltration). Results: The PAS-positive area in the saline group was significantly lower than that in the normal group (36.9±2.6 vs. 66.9±1.2%, P<0.01); the PAS-positive area in the edaravone group remained comparable to that in the normal group (52.9±0.9%, P<0.01). Esterase-positive cells in the saline group were significantly higher than in normal kidneys (62.4±5.6 vs. 17.5±2.4 cells/mm2, P<0.01), while they were significantly reduced in the edaravone group (32.8±5.7 cells/mm2, P<0.01). Conclusion: Edaravone pretreatment mitigates MNMS-induced kidney damage by reducing both glycogen depletion and neutrophil infiltration.

A Case of Acute Thrombosis of Abdominal Aortic Aneurysm / 日本心臓血管外科学会雑誌

An 80-year-old man felt a loss of strength and sharp pain in both lower limbs while playing gate-ball, consulted a nearby doctor, and was followed up. Because the sharp pains in both lower limbs became aggravated the next day, he was given a previously prescribed medication. Both femoral pulses were absent and acute arterial obstruction of the lower limbs was suspected. A contrast-enhanced CT scan showed a thrombosed infrarenal abdominal aortic aneurysm with a maximum transverse diameter of 37 mm, and both external iliac arteries were contrast imaged by collateral circulation pathways. We diagnosed acute thrombosis of an abdominal aortic aneurysm, and was urgently transported to our hospital. We classified his lower limbs as Balas grade III and TASC classification grade IIb and Rutherford classification grade IIb. He exhibited no abdominal symptoms and since we confirmed the blood flow of his lower limbs, we decided to perform revascularization. An extra-anatomical bypass (axillo-bifemoral bypass) was conducted because he had dementia, and was old. After the operation, myonephropathic metabolic syndrome (MNMS) did not develop, and the patient was discharged on foot on the 16th postoperative day. Acute thrombosis of an abdominal aortic aneurysm is a rare disease. Because the ischemic area widens, often causing serious MNMS after the revascularization, it has a poor prognosis. Here, we report a case in which one such patient was rescued.

Successful Open Graft Replacement for Acute Stanford Type B Aortic Dissection with Bilateral Lower Limb Ischemia and Postoperative Myonephropathic Metabolic Syndrome / 日本心臓血管外科学会雑誌

A 52-year-old man suddenly felt severe back pain and numbness in the lower extremities. Enhanced CT revealed an acute Stanford type B dissection. The true lumen of the left common iliac artery was severely compressed by the thrombosed false lumen. We performed a femoro-femoral bypass and symptoms in the lower limbs disappeared. On day 4 of hospitalization, the patient suddenly presented with pain at rest and cyanosis in both lower extremities. CT revealed nearly total occlusion of the abdominal aorta due to severe compression of the false lumen. We performed emergency open graft replacement in the infrarenal aorta. Although ischemia in the lower extremities improved, the patient developed myonephropathic metabolic syndrome (MNMS) and received continuous hemodiafiltration to treat acute renal insufficiency. The patient's ankle-branchial pressure index improved and he was weaned from continuous hemodiafiltration. The patient had no paralysis and was able to walk unassisted, so he was discharged on day 34 of hospitalization. In the event of acute aortic dissection and organ ischemia, emergency open graft replacement may be required and must be performed promptly as a lifesaving measure.

A Successful Treatment for Myonephropathic Metabolic Syndrome and Delayed Intestinal Ischemia after Operation of Acute Type B Aortic Dissection with Bilateral Lower Limb Ischemia / 日本心臓血管外科学会雑誌

A 20-year-old man suddenly complained of back pain and bilateral lower limb weakness. Computed tomography showed acute type B aortic dissection. The patent false lumen extended from distal arch to the left common iliac artery. The true lumen was severely compressed by the false lumen and both legs were ischemic. He underwent emergency fenestration of the abdominal aorta and stenting of the left iliac artery. Although the lower limbs ischemia was improved, he developed myonephropathic metabolic syndrome and received plasma exchange, continuous hemodialysis and endotoxin absorption therapy. Thirteen days after the operation, intestinal ischemia occurred and he underwent emergency bowel resection with creation of a stoma. Development of dissection to the superior mesenteric artery (SMA) and the malperfusion of SMA by severe compression of the true lumen were thought to cause intestinal ischemia.

Myonephropathic Metabolic Syndrome following Femoral Arterial Cannulation / 日本心臓血管外科学会雑誌

Between 1999 and 2004, 337 cardiovascular surgical procedures using cardiopulmonary bypass were conducted in our institution. Femoral arterial cannulation was performed in 130 cases (38.6%) and 3 of these cases, all men aged under 60, developed compartment syndrome in the ipsilateral leg. The ischemic time of the leg was between 240 and 294min. Two of them developed myonephropathic metabolic syndrome (MNMS) and underwent continuous hemodiafiltration. Two of the cases were ambulant on discharge from hospital but one died. Compartment syndrome and MNMS are serious complications, and must be prevented rather than treated. Young male patients are at increased risk of these complications, and are often reported in Japan. In order to prevent leg ischemia during femoral Cannulation, care should be taken not to disrupt deep femoral arterial flow (which is the collateral inflow) or superficial femoral arterial flow. When back flow from the profunda femoris artery is inadequate, peripheral perfusion should be performed to avoid leg ischemia.

Surgical Treatment of Acute Abdominal Aortic Occlusion / 日本心臓血管外科学会雑誌

Acute aortic occlusion is an infrequently observed but frequently fatal event requiring prompt surgical treatment. We encountered 4 cases of acute non-aneurysmal abdominal aortic occlusion caused by different mechanisms and reviewed the literature concerning surgical management. The patients consisted of 2 men and 2 women with a mean age of 68.7±5.7 years (range, 63 to 75 years). Three of the 4 patients had a history of atrial fibrillation. Clinical presentations included acute limb ischemia and neurological deficit in all 4 cases. The mechanisms of acute aortic occlusion were mainly divided into embolisms and thrombosis related to aortoiliac occlusive disease. Operation was done at mean intervals of 8.6h (range, 5 to 11h). Two patients underwent transfemoral thrombectomy under local anesthesia, one thromboendarterectomy under laparotomy on hemodialysis, and one axillobifemoral bypass procedure. One patient had to undergo fasciotomy immediately because of compartment syndrome, 2 other patients needed additional procedures (one had femoro-popliteal bypass and the other had mitral valve replacement). The perioperative mortality rate was 25%, related to massive cerebral infarction. The outcomes of these patients depend on prompt diagnosis, systemic heparinization and early revascularization by appropriate operation; initial attempt of transfemoral thrombectomy, and axillobifemoral bypass in high risk patients. After revascularization, patients must be carefully monitored for reperfusion syndrome, myonephropathic metabolic syndrome, acute renal failure and compartment syndrome.

Myonephropathic Metabolic Syndrome after Cardiac or Aortic Surgery / 日本心臓血管外科学会雑誌

Myonephropathic metabolic syndrome (MNMS) is a fatal complication following open-heart or aortic surgery. We evaluated 7 cases of MNMS following cardiac or aortic surgery. The patient's ages ranged from 43 to 81 years old. Of the 7 patients, four presented with myocardial infarction, which required coronary artery bypass grafting (CABG), and three presented with acute aortic dissection. Two patients with Stanford type A underwent total arch replacement and CABG and 1 patient with Stanford type B underwent a left axillo-femoral bypass. MNMS was caused by acute arterial occlusion due to intra-aortic balloon pumping (IABP) or percutaneous cardio-pulmonary support (PCPS) in patients who experienced myocardial infarction and acute lower limb ischemia in patients who experienced aortic dissection. The ratio of MNMS caused by IABP and PCPS, and acute aortic dissection was 1.4% and 4.2%, respectively. Four patients died; 3 had undergone CABG and 1 had undergone an aortic operation 18.5h after acute dissection. Both IABP and PCPS were removed early in possible cases. Limb wash-out was performed in 1 patient, and 5 were treated with hemodiafiltration. IABP and PCPS should be introduced via a prosthetic graft if limb ischemia is noticed. MNMS should be recognized as a disastrous complication of aortic dissection, and early bypass graft or limb amputation may become the treatment of choice. We emphasize that hemodiafiltration should begin as soon as MNMS is diagnosed.

A Case of Ischemic Limb Perfusion during Cardiopulmonary Bypass / 日本心臓血管外科学会雑誌

A 64-year-old woman with chest pain and intermittent claudication was admitted to our hospital. Unstable angina pectoris and arteriosclerosis obliterans (ASO) of both leg were diagnosed. Angiography indicated total occlusion of the right external iliac artery and severe stenosis of the left external iliac artery, in addition to significant stenoses of the three major coronary arteries. The ankle pressure index was 0.49 in her right leg, and 0.74 in the left. Because coronary stenting was unsuccessful, emergency coronary artery bypass grafting was performed prior to arterial reconstruction of the lower extremities. To prevent exacerbation of limb ischemia during cardiopulmonary bypass (CPB), selective limb perfusion was performed with a 14-gauge intravenous catheter inserted into the right superficial femoral artery. There were no complications related to limb ischemia during or after the operation. Selective limb perfusion was considered to be useful to prevent limb ischemia during CPB in patients with ASO of the legs.

A Case of Myonephropathic Metabolic Syndrome after Coronary Artery Bypass Grafting with Severe Arteriosclerosis Obliterans / 日本心臓血管外科学会雑誌

A 70-year-old man with a diagnosis of unstable angina pectoris (UAP) and arteriosclerosis obliterans (ASO) was admitted to our hospital with chest pain and intermittent claudication of both lower extremities. Coronary artery bypass grafting (CABG) was performed prior to peripheral arterial reconstruction due to UAP. He was in good condition after CABG, but he had sharp pain in both lower extremities suddenly on the 2nd postoperative day and the creatinine phosphokinase level increased to 17, 560IU/<i>l</i>. On the 3rd postoperative day axillo-bifemoral bypass was performed. However 5 hours after the revascularization, respiratory arrest and ventricular fibrillation occurred and he died in spite of attempted cardiopulmonary resuscitation.

The Role of Systemic Inflammatory Response Syndrome for Acute Arterial Occlusion of the Lower Limb / 日本心臓血管外科学会雑誌

Reperfusion injury occasionally occurred after revasculization of acute arterial occlusion (AAO). The most common reason of death is myonephropatic metabolic syndrome due to reperfusion injury. This paper focusses on the criterion of systemic inflammatory response syndrome (SIRS). From January 1987 to April 1996, we treated 89 patients (male 59/female 30) with lower limb AAO. The mean age was 68.5 (ranging from 16 to 94) years old. There were 59 cases of thrombosis, 25 of embolism, 2 trauma and 3 dissecting aneurysm of the aorta. These patients were divided into two groups according to whether or not they fulfilled the criterion of SIRS. Of these patients, 46 cases met the criterion of SIRS (SIRS group) but the other 43 did not (non-SIRS group). We compared the two groups. The mortality of the SIRS group (23.9%) was higher than the non-SIRS group (2.3%). The ischemic time of the SIRS group (83.1±113.3 hours) was longer than the non-SIRS group (37.5±38.2 hours). Complications of MNMS were more common in the SIRS group (15.3%) than in the non-SIRS group (2.3%). The ischemic area in the SIRS group was remarkably less than in the non-SIRS group. Conclusion: The criterion of SIRS as indicated by the measurement of interleukin 8 (IL-8) was a useful prognostic parameter for limb salvage rate and mortality of AAO patients.

The Role of ICAM-1 and IL-8 in Reperfusion Injury Following Acute Arterial Occlusion of the Extremities / 日本心臓血管外科学会雑誌

A model of reperfusion injury following acute arterial occlusion was made in Wistar strain rat. Using this model, changes in and the role of interleukin-8 (IL-8) and intercellular adhesion molecule-1 (ICAM-1) were estimated. The rats were divided into two groups as follows; the infra-renal aorta and the bilateral common femoral artery were ligated for six hours and released (reperfusion group, <i>n</i>: 4), and only preparation of these arteries with no clamp was performed in the control group (<i>n</i>: 4). CPK and IL-8 were measured, and various organs (heart, lung, kidney, femoral artery and carotid artery) were extracted, then ICAM-1 was evaluated immunohistochemistrically, using anti-rat ICAM-1 antibody (1A29). CPK showed a significantly high value in the reperfusion group. After the reperfusion, IL-8 increased significantly and remained high in the reperfusion group. Immunohistologically, the manifestation of ICAM-1 was recognized in the various organs of the reperfusion group. These results suggests that the high IL-8 values and the manifestation of ICAM-1 were caused by disorders in various organs by neutrophils, and these mechanisms may be related to the incidence of myonephropathic metabolic syndrome (MNMS), which is caused by acute arterial occlusion disease.

The Role of Leukocytes in Reperfusion Injury Following Acute Arterial Occlusion of the Lower Extremities / 日本心臓血管外科学会雑誌

<b>Purpose</b>. To determine the involvement of leukocytes in reperfusion injury following acute arterial occlusion of the lower extremities, the effect of leukocyte removal filters or leukotrien B4 (LTB4) antagonist was investigated using a canine acute arterial occlusion model. <b>Methods</b>. Twenty-eight mongrel dogs, weighing 15 to 20kg, underwent temporal occlusion of the infrarenal aorta and lumbar arteries followed by release of occlusion 12 hours later. Experimental groups consisted of the three following groups: Group I (<i>n</i>=12; control), dogs without any treatment; Group II (<i>n</i>=8), dogs treated with leukocyte removal filters from the onset of reperfusion until one hour after reperfusion; and Group III (<i>n</i>=8), dogs pretreated with LTB4 antagonist immediately before reperfusion. Serum myoglobin, CPK, and GOT were measured and compared among the three groups. <b>Results</b>. Values of serum myoglobin, CPK, and GOT, were significantly elevated after reperfusion in Group I as compared to those before reperfusion. However, increase in these values was significantly elevated after reperfusion in Group I as compared to those before reperfusion. However, increase in these values was significantly attenuated in Group II and Group III as compared to Group I. <b>Conclusions</b>. These data suggested leukocyte depletion injury following acute arterial occlusion of the lower extremities. Leukocytes appear to play a significant role in this type of reperfusion injury.

Acute Abdominal Aortic Occlusion: Two Cases of Successful Prophylaxis of Myonephropathic Metabolic Syndrome / 日本心臓血管外科学会雑誌

We report two cases, a 58-year-old male and a 60-year-old female with acute aortic occlusion probably ascribable to intracardiac thrombosis associated with atrial fibrillation. Thrombectomy was performed at about 5.5 hours and 4 hours respectively, after the onset of occlusion, and revascularization was successful. To prevent MNMS after revascularization, about 2, 000ml of blood was taken from the femoral vein of the male patient, and 1, 000ml of blood from the female patient, and this blood was returned in the form of abluted erythrocytes in transfusion through a cell saver to the patients. We suspected slight myoglobinuria after the operations, but they did not develop MNMS because a urine volume of about 3, 000ml was maintained by administration of infusion solution and diuretics and by replenishment of electrolytes and correction of acidosis. It was concluded that the technique involving the removal of a large volume of blood from distal veins and its transfusion through a cell saver was effective in preventing MNMS.

A Case Report of Abdominal Aortic Aneurysm with Acute Thrombosis / 日本心臓血管外科学会雑誌

A 58-year-old male was unable to walk because of progressive pain in both lower extremities that rapidly became cold and clammy. Femoral, popliteal and ankle pulses ware absent, and there was a pulsatile tumor in the abdomen. Abdominal CT showed an abdominal aortic aneurysm that measured 50mm in diameter. Aortogram revealed total infrarenal aortic occlusion. The patient underwent emergency aorto-bifemoral bypass with a bifurcated artificial graft. Several days after the operation, renal failure appeared because of MNMS. He was weaned from hemodialysis at one month and was discharged from hospital about 1 year after the operation.

Comparison between Arteriosclerotic Thrombosis and Embolism in Acute Arterial Occlusive Disease / 日本心臓血管外科学会雑誌

During the period between January 1975 and April 1991, 37 patients with acute arterial occulusion of the extremities were admitted to our department and were classified into 2 groups according to their causative factors, including thrombosis and embolism. Among 16 thrombosis patients with involvement of 17 limbs, 4 patients died and 6 limbs were amputated at the time of discharge. On the contrary, among 21 embolism patients with involvement of 25 limbs, 2 patients died and only one limb was amputated. Sixteen of 17 limbs with thrombosis were operated on. Arterial reconstruction was carried out initially on 5 limbs, resulting in successful limb salvage; 3 of 6 limbs which had undergone thrombectomy initially were occluded again soon after the procedure. In the end, 1 limb had to be amputated. On the other hand, 22 of 25 limbs were operated on. Three arterial reconstructions, 18 embolectomies and 1 amputation were carried out initially. All arterial reconstructions and embolectomies were successful. From these results, it was concluded that arterial reconstruction must be done initially for thrombosis patients. For the embolism patients, embolectomy is preferable.