pH-Tolerant giant vesicles composed of cationic lipids with imine linkages and oleic acids

Giant vesicles (GVs) have attracted attention as functional materials because they can encapsulate both hydrophilic and hydrophobic compounds. For next generation functional GVs, both tolerance and stimuli-sensitivity are needed. So far, vesicles tolerant to acidic or basic conditions were generated using a mixture of cationic lipids and fatty acids. Here, to create functional GVs that are tolerant to a wide pH range but sensitively respond at below a specific pH, the behaviour of GVs composed of a cationic lipid with an imine bond and oleic acid was investigated. Even though the GVs prepared by the film swelling method were tolerant to strongly acidic conditions, GVs without oleic acid gradually shrank, accompanied by the generation of oil droplets at the same pH. ¹H NMR analysis revealed that during hydration of the film, the imine bond hydrolysed to provide a cationic surfactant and an oil component in the presence of oleic acid due to its own Lewis basicity, suggesting the dissociation of oleic acid. The results of fluorescence spectroscopy using an environment-responsive probe and IR spectroscopy indicated that the GV tolerance originated from the intermolecular interactions of cationic lipids and anionic oleate.

Giant vesicles composed of cationic lipids having an imine linkage and oleic acid were stable at strong acidic conditions.     

An autopsy case of isolated eosinophilic coronary periarteritis: a limited form of Churg-Strauss syndrome or a new entity?

A 52-year-old man without a history of asthma or allergic diseases died of ventricular fibrillation early in the morning. His autopsy revealed no significant findings, except for a mild mural-thickening localized at the proximal region of the right coronary artery. Microscopic examination showed periarteritis with infiltration of numerous eosinophils in the adventitia. No significant vasculitis was found in any other organs. Based on the findings this seems to be the second reported case of isolated eosinophilic coronary periarteritis.     

Infection mechanism of biofilm‐forming Staphylococcus aureus on indwelling foreign materials in mice

Indwelling foreign‐body infections are a critical medical problem, especially in immunocompromised patients. To examine the pathogenicity of biofilm‐forming bacteria settling on foreign materials, mice implanted with plastic discs were infected with Staphylococcus aureus. After opening a wide subcutaneous pocket on the dorsal side of mice with or without temporal leukocytopenia, a plastic sheet was placed in the left subcutaneous space; subsequently, bacteria in a planktonic state were dispersed over the subcutaneous space. Bacterial numbers were examined 7 days after inoculation. In subcutaneous tissue on the right, S. aureus was found only in leukocytopenic mice. Meanwhile, bacteria were detected on the plastic and neighbouring tissue in both leukocytopenic and normal mice; however, colony‐forming analysis indicated that leukocytopenic mice possessed significantly more bacteria. Tissue reaction against bacteria was pathologically examined. Invading S. aureus induced severe inflammation. In transient leukocytopenic mice, bacterial microcolonies formed on the plastic as well as in the developed necrotic tissue – both of which were shielded from inflammatory cell infiltration – result in bacteraemia. These results indicate that biofilm‐forming S. aureus settling on indwelling foreign material are tolerant against host immunity and assault neighbouring tissue, which may lead to chronic wound infection.     

Progressive nature of paroxysmal atrial fibrillation. Observations from a 14-year follow-up study.

BACKGROUND: Atrial fibrillation (AF) is believed to occur first as paroxysmal, then be gradually perpetuated, and finally become chronic as the end result. However, this presumed clinical course has not been well confirmed. METHODS AND RESULTS: The clinical course of recurrent paroxysmal AF (PAF) from its onset was examined in 171 patients (mean follow-up period: 14.1+/-8.1 years). This study population consisted of patients with no structural heart disease (n=88), ischemic heart disease (n=28), dilated or hypertrophic cardiomyopathy (n=17), valvular heart disease (n=35) or other cardiac diseases. The mean age at the onset of AF was 58.3 +/-11.8 years old. During the mean follow-up period of 14.1 years, PAF eventually developed into its chronic form in 132 patients under conventional antiarrhythmic therapy (77.2%, 5.5% of patients per year). The independent factors for early development into chronic AF were aging (hazard ratio (HR) 1.27 per 10 years, 95% confidence interval (CI) 1.06-1.47)), dilated left atrium (HR 1.39 per 10 mm, 95% CI 1.11-1.69), myocardial infarction (HR 2.33, 95% CI 1.13-4.81), and valvular diseases (HR 2.29, 95% CI 1.22-4.30). CONCLUSIONS: The present long-term observations definitely and quantitatively revealed the progressive nature of PAF.     

Significance of Pseudomonas aeruginosa colonization of the gastrointestinal tract

OBJECTIVE: This study was conducted to determine the association between gastrointestinal (GI) colonization and the development of invasive Pseudomonas aeruginosa infections and risk factors for acquisition of P. aeruginosa colonization in gut. METHODS: All stool specimens sent for microbiological examination were cultured for P. aeruginosa search for three years. PATIENTS AND MATERIALS: P. aeruginosa had been isolated from stool of 207 patients for three years. Of the 207 patients, 87 patients were identified P. aeruginosa-colonized patients. RESULTS: Forty-five (52%) were exposed to previous invasive procedures and eighty-three (95%) were prescribed antibiotics before the isolation of P. aeruginosa. Fourteen distinctive P. aeruginosa infections were developed in 13 patients (15%). Infections associated with GI colonization included 4 pneumonia, 4 urinary tract infection, 3 skin infection, and 3 bacteremia. The age, gender, underlying diseases, previous invasive procedures, and the duration of hospitalization were not significant. Twelve (34%) patients were diagnosed with ileus and three (9%) were undergoing gastrostomy during the acquisition of P. aeruginosa colonization in gut. CONCLUSION: Gastrointestinal disorders, especially obstruction and surgical interventions, are also important for the acquisition of by P. aeruginosa, in the GI tract.     

A case of pulmonary sarcoidosis with usual interstitial pneumonia-like lesions distributed predominantly in the lower lung fields]

In 2000, in a 75-year-old man, nodular and reticular opacities were detected in both lower lung fields. He was admitted to our hospital for further examination of these abnormal shadows. Bronchoscopic examination revealed pulmonary sarcoidosis. Prednisolone was prescribed because cardiac sarcoidosis was diagnosed as a clinical complication. In April 2002, the patient visited our hospital for dyspnea on effort. Chest radiography and computed tomography showed nodular and reticular opacities in the right upper lobe, and video-assisted thoracoscopic surgery was performed on the basis of a histological diagnosis. The histological findings of the biopsied specimens revealed a lesion of the type seen in usual interstitial pneumonia, whereas non-caseous granulomas were not detected. His symptoms and chest radiographic findings improved and stabilized with prednisolone and azathioprine. In the present case of pulmonary sarcoidosis, the reticular and nodular opacities predominantly distributed in both lower lung fields, and the histological findings obtained by video-assisted thoracoscopic surgery showed a usual interstitial pneumonia-like lesion. These findings may assist in the understanding of the process of development of pulmonary sarcoidosis.     

Effect of ethanol on endothelin-1 release from gastric vasculature

The effects of ethanol on gastric vasculature in isolated vascularly perfused rabbit stomach was investigated. The isolated stomach was perfused with Krebs-Henseleit solution containing 3% dextran bubbled with 95% O₂ and 5% CO₂ at a rate of 12 ml/min. After mixture and perfusion of 10 mM to 400 mM of ethanol, perfusion pressure and endothelin-1 concentration in effluent from gastric vasculature were measured. Perfusion pressure and endothelin-1 concentration in effluent increased in a dose-dependent manner with increasing ethanol concentrations. In conclusion, the data suggest that ethanol may stimulate the release of endothelin from gastric vasculature and may cause gastric ischemia due to vasoconstriction resulting in acute gastric mucosal injury.