O2 activation by core–shell Ru13@Pt42 particles in comparison with Pt55 particles: a DFT study

The reaction of O₂ with a Ru₁₃@Pt₄₂ core–shell particle consisting of a Ru₁₃ core and a Pt₄₂ shell was theoretically investigated in comparison with Pt₅₅. The O₂ binding energy with Pt₅₅ is larger than that with Ru₁₃@Pt₄₂, and O–O bond cleavage occurs more easily with a smaller activation barrier (E_a) on Pt₅₅ than on Ru₁₃@Pt₄₂. Protonation to the Pt₄₂ surface followed by one-electron reduction leads to the formation of an H atom on the surface with considerable exothermicity. The H atom reacts with the adsorbed O₂ molecule to afford an OOH species with a larger E_a value on Pt₅₅ than on Ru₁₃@Pt₄₂. An OOH species is also formed by protonation of the adsorbed O₂ molecule, followed by one-electron reduction, with a large exothermicity in both Pt₅₅ and Ru₁₃@Pt₄₂. O–OH bond cleavage occurs with a smaller E_a on Pt₅₅ than on Ru₁₃@Pt₄₂. The lower reactivity of Ru₁₃@Pt₄₂ than that of Pt₅₅ on the O–O and O–OH bond cleavages arises from the presence of lower energy in the d-valence band-top and d-band center in Ru₁₃@Pt₄₂ than in Pt₅₅. The smaller E_a for OOH formation on Ru₁₃@Pt₄₂ than on Pt₅₅ arises from weaker Ru₁₃@Pt₄₂–O₂ and Ru₁₃@Pt₄₂–H bonds than the Pt₅₅–O₂ and Pt₅₅–H bonds, respectively. The low-energy d-valence band-top is responsible for the weak Ru₁₃@Pt₄₂–O and Ru₁₃@Pt₄₂–OH bonds. Thus, the low-energy d-valence band-top and d-band center are important properties of the Ru₁₃@Pt₄₂ particle.

In this theoretical study by DFT computations, characteristic features of the Ru₁₃@Pt₄₂ core–shell particle in O₂ activation are clearly discussed in comparison with Pt₅₅.     

Successful laparoscopic extirpation of a large omental lipoblastoma in a child

Omental lipoblastoma is extremely rare among benign tumors. We herein report the case of a child who underwent laparoscopic extirpation of a large omental lipoblastoma. A 4‐year‐old girl was diagnosed with an intra‐abdominal solid tumor. Abdominal imaging revealed a fat density mass that was well encapsulated and measured 18 × 15 × 7.5 cm in size. Considering the MRI findings and movability of the tumor, we strongly suspected that the lesion was an omental lipoblastoma. We initially decided to perform laparoscopic exploration and, if possible, extirpation of the solid tumor sequentially. A total of five trocars were used, and the tumor was found to originate from the omentum. We successfully performed complete resection of the tumor laparoscopically. A histological examination revealed lipoblastoma. For large abdominal tumors in children, the laparoscopic approach is recommended as the first procedure when the tumor is preoperatively considered to be benign and resectable.     

Sequential monitoring of serum IL-6, TNF-α, and IFN-γ levels in a CAEBV patient treated by plasma exchange and immunochemotherapy

We report the case of a female patient with chronic active Epstein?CBarr virus infection (CAEBV) accompanied by hemophagocytic syndrome (HPS). On admission, she presented with severe liver dysfunction and disseminated intravascular coagulation with elevation of serum IL-6, TNF-??, and IFN-?? levels. Plasma exchange (PE) followed by immunochemotherapy with prednisolone, cyclosporine A, and VP16 was performed. PE decreased serum cytokine levels dramatically and improved liver function. Following immunochemotherapy, CAEBV became inactive. Four months after discharge, however, CAEBV relapsed with HPS, and serum cytokine levels were extremely elevated again. There was no response to immunochemotherapy, and the patient died 1?day after admission. We examined the cytokines in five additional untreated-CAEBV patients and determined that they were elevated above the normal level in all patients. These results suggest that inflammatory cytokines may have roles in the development of CAEBV, and that their depletion can be an effective treatment for this disease.     

Beta-blocker stress echocardiography in an aortic stenosis patient with associated left ventricular outflow tract obstruction

An 80-year-old man visited our hospital because of dyspnea on exertion from 6 months ago. Echo Doppler study showed severe calcification in the aortic valve with restricted movement and the sigmoid septum causing obstruction at the LV outflow tract (LVOT). Considering the aortic valve area (AVA) might have been inaccurately estimated, we carried out beta-blocker stress echocardiography. The transaortic pressure gradient and AVA were respectively calculated as 52 mmHg and 0.90 cm² before propranolol administration and as 64 mmHg and 0.86 cm² after propranolol administration. Thus, beta-blocker stress echocardiography may provide an accurate assessment of AS if the LVOT obstruction is concomitant.     

Enhanced heat shock protein 25 immunoreactivity in cranial nerve motoneurons and their related fiber tracts in rats prenatally‐exposed to X‐irradiation

Alterations in histoarchitecture of the brainstem were examined immunohistochemically in 4‐week‐old rats with a single whole body X‐irradiation at a dose of 0.5, 1.0, or 1.5 Gy on embryonic day (ED) 15 using anti‐heat shock protein 25 (HSP25). HSP25 immunostaining was seen in the neuronal perikarya of cranial nerve motoneurons, that is, the motor and mesencephalic nuclei of the trigeminal nerve, facial nucleus, abducens nucleus and accessory facial nucleus in the pons, and the ambiguous nucleus, dorsal nucleus of vagus nerve and hypoglossus nucleus in the medulla oblongata of intact controls. In 0.5 to 1.5 Gy‐irradiated rats, HSP25 immunostaining in those neurons was more intense than in controls, while the most intense immunostaining was marked in 1.5 Gy‐irradiated rats. HSP25 immunostaining was also apparent in the spinal tract of the trigeminal nerve and facial nerve tracts in 0.5 to 1.5 Gy‐irradiated rats, but was faint in controls. Interestingly, HSP25 immunostaining was aberrantly enhanced in dendritic arbors in the magnocellular region of medial vestibular nucleus of 0.5–1.5 Gy‐irradiated rats. Those arbors were identified as excitatory secondary vestibulo‐ocular neurons by double immunofluorescence for HSP25 and SMI‐32. The results suggest an increase of HSP25 expression in cranial nerve motoneurons and their related fiber tracts from prenatal exposure to ionizing irradiation. This may be an adaptive response to chronic hypoxia due to malformed brain arteries caused by prenatal ionizing irradiation.     

Molecular cloning of infectious proviral genomes of bovine leukemia virus

Covalently closed circular DNA molecules of bovine leukemia virus were cloned in the lambda phage vector lambda gtWES-lambda B and subsequently in the plasmid vector pUC12. Proviral DNAs of 8.3 kb which have one copy of a long terminal repeat and uniform restriction endonuclease sites were preferentially obtained. Four randomly selected clones were examined for their biological activities by DNA transfection experiments. The ovine embryonic cells transfected with these clones formed syncytia which represent the expression of BLV genes. The infectious virions could be recovered from the transfectants.     

Vector potential of cockroaches for Helicobacter pylori infection

OBJECTIVES: The routes of human infection with Helicobacter pylori remain unclear. In the present study, we examined cockroaches as possible vectors for transmission of H. pylori. METHODS: We used a common species of cockroach (Periplaneta fuliginosa). After a 3-day fast, cockroaches were placed on agar plates containing freshly grown H. pylori (Sydney strain) (challenge group) or on sterile agar plates without H. pylori (control group). After 24 h of challenge, cockroaches were moved to disinfected containers, and sterile food and water were provided. The external surfaces (legs and body) and excreta of the cockroaches were sampled for culture, rapid urease test, and polymerase chain reaction (PCR). RESULTS: H. pylori were culturable from the excreta of the challenge group for 24 h postchallenge. Positive rapid urease test results were obtained up to day 3, and PCR analysis was positive for H. pylori DNA up to day 7 from the excreta. In contrast, H. pylori were not culturable from the external surfaces of the cockroaches. The rapid urease test was positive for only 8 h, and PCR analysis was positive for H. pylori DNA for 1 day from the external surface. CONCLUSIONS: Cockroaches usually live in unsanitary environments and may contaminate foods and food containment areas such as pantries. Transmission of H. pylori infection could be achieved via inadvertent ingestion of foods contaminated with cockroach excreta containing viable H. pylori.     

Dual-probe assay for rapid detection of drug-resistant Mycobacterium tuberculosis by real-time PCR

Mutations in particular nucleotides of genes coding for drug targets or drug-converting enzymes lead to drug resistance in Mycobacterium tuberculosis. For rapid detection of drug-resistant M. tuberculosis in clinical specimens, a simple and applicable method is needed. Eight TaqMan minor groove binder (MGB) probes, which discriminate one-base mismatches, were designed (dual-probe assay with four reaction tubes). The target of six MGB probes was the rpoB gene, which is involved in rifampin resistance; five probes were designed to detect for mutation sites within an 81-bp hot spot of the rpoB gene, and one probe was designed as a tuberculosis (TB) control outside the rpoB gene hot-spot. We also designed probes to examine codon 315 of katG and codon 306 of embB for mutations associated with resistance to isoniazid and ethambutol, respectively. Our system was M. tuberculosis complex specific, because neither nontuberculous mycobacteria nor bacteria other than mycobacteria reacted with the system. Detection limits in direct and preamplified analyses were 250 and 10 fg of genomic DNA, respectively. The system could detect mutations of the rpoB, katG, and embB genes in DNAs extracted from 45 laboratory strains and from sputum samples of 27 patients with pulmonary TB. This system was much faster (3 h from DNA preparation) than conventional drug susceptibility testing (3 weeks). Results from the dual-MGB-probe assay were consistent with DNA sequencing. Because the dual-probe assay system is simple, rapid, and accurate, it can be applied to detect drug-resistant M. tuberculosis in clinical laboratories.     

Pael receptor induces death of dopaminergic neurons in the substantia nigra via endoplasmic reticulum stress and dopamine toxicity, which is enhanced under condition of parkin inactivation

Selective loss of dopaminergic neurons is the final common pathway in Parkinson's disease. Expression of Parkin associated endothelin-receptor like receptor (Pael-R) in mouse brain was achieved by injecting adenoviral vectors carrying a modified neuron-specific promoter and Cre recombinase into the striatum. Upregulation of Pael-R in the substantia nigra pars compacta of mice by retrograde infection induced endoplasmic reticulum (ER) stress leads to death of dopaminergic neurons. The role of ER stress in dopaminergic neuronal vulnerability was highlighted by their decreased survival in mice deficient in the ubiquitin-protein ligase Parkin and the ER chaperone ORP150 (150 kDa oxygen-regulated protein). Dopamine-related toxicity was also a key factor, as a dopamine synthesis inhibitor blocked neuronal death in parkin null mice. These data suggest a model in which ER- and dopamine-related stress are major contributors to decreased viability of dopaminergic neurons in a setting relevant to Parkinson's disease.