MRI study of atherosclerotic plaque progression using ultrasmall superparamagnetic iron oxide in Watanabe heritable hyperlipidemic rabbits

OBJECTIVE

The purpose of this study was to evaluate plaque progression by using MRI with ultrasmall superparamagnetic iron oxide (USPIO) and by histopathological studies.

METHODS

We divided 12 Watanabe heritable hyperlipidemic (WHHL) rabbits into 4 groups based on their age (3, 9, 14 and 26 months) and injected them intravenously with 0.8 mmol (Fe) kg(-1) of USPIO (size, 32 nm; concentration, 15 mg dl(-1)). On the fifth post-injection day, they were again given an intravenous injection with 40 μmol kg(-1) of the same USPIO, and MR angiography (MRA) was performed. The signal-to-noise ratio (SNR) in regions of interest in the wall of the upper abdominal aorta was calculated on coronal images. Specimens from the same level of the aorta were subjected to iron staining and RAM-11 immunostaining and used for histopathological study. For statistical analysis of the MRA and histopathological findings, we used analysis of variance [Tukey's honest significant difference (HSD) test].

RESULTS

In 9-month-old rabbits, the SNR was significantly lower than in rabbits of the other ages (p < 0.01), and the area of RAM-11 (DAKO Corporation, Glostrup, Denmark) and iron uptake in the aortic wall was significantly larger (RAM-11, p < 0.01; iron, p < 0.05). These areas were the smallest in 3-month-old rabbits.

CONCLUSION

Histopathologically, the number of macrophages was the greatest in 9-month-old rabbits. Our findings indicate that the SNR on MRI scans reflects the number of macrophages in the aortic wall of WHHL rabbits.

ADVANCES IN KNOWLEDGE

USPIO-enhanced MRI visualized the accumulation of macrophages in early atherosclerotic plaques of WHHL rabbits in the course of natural progression.

Development of an MR-compatible configurable brush stimulation device

In order to evaluate sensory disturbance, a subjective method is performed, so that the evaluation result is influenced by subjective factors. fMRI is used for observing brain activity objectively. Therefore the brain response to a stimulation measured by fMRI could become a useful identification tool for the objective evaluation of the sensory disturbance. The purpose of this study is to develop an MR-compatible sensory stimulation device capable of providing brush stimulation to several positions with separate modules, and to confirm the feasibility of the device by a basic operation experiment and an fMRI experiment. The developed device consists of both an MR-compatible stimulator placed inside the MRI room, a tube-rod mechanism and a driver placed outside the MRI room. The tube-rod mechanism is adopted for power transmission from the driver to the stimulator. Also, in order to provide the stimulation to several positions in the limited space, the device consists of the stimulation module and the positioning module that moves the stimulation module. For the basic operation experiment, we measure a variation of the automated and manual brush stimulation period. For the fMRI experiment, the brush stimulation is provided to the middle fingertip and the palm of a subject in a trial using the developed device. As a result, the standard deviations of the automated brush stimulation period is less than 7.0 ms. This result was smaller than that of the manual stimulation period. Also, the brush stimulation to the fingertip and the palm activated the somatosensory areas respectively. In conclusion, we confirmed the feasibility of the developed device through the experiments.

Visible-light-controlled homo- and copolymerization of styrenes by a bichromophoric Ir–Pd catalyst

Visible-light-controlled polymerization was achieved by a bichromophoric organopalladium catalyst which possesses a naphthyl-substituted cyclometallated Ir(iii) light-absorbing moiety.

Exceptionally high glucose current on a hierarchically structured porous carbon electrode with "wired" flavin adenine dinucleotide-dependent glucose dehydrogenase

This article introduces a carbon electrode designed to achieve efficient enzymatic electrolysis by exploiting a hierarchical pore structure based on macropores for efficient mass transfer and mesopores for high enzyme loading. Magnesium oxide-templated mesoporous carbon (MgOC, mean pore diameter 38 nm) was used to increase the effective specific surface area for enzyme immobilization. MgOC particles were deposited on a current collector by an electrophoretic deposition method to generate micrometer-scale macropores to improve the mass transfer of glucose and electrolyte (buffer) ions. To create a glucose bioanode, the porous-carbon-modified electrode was further coated with a biocatalytic hydrogel composed of a conductive redox polymer, deglycosylated flavin adenine dinucleotide-dependent glucose dehydrogenase (d-FAD-GDH), and a cross-linker. Carbohydrate chains on the peripheral surfaces of the FAD-GDH molecules were removed by periodate oxidation before cross-linking. The current density for the oxidation of glucose was 100 mA cm(-2) at 25 °C and pH 7, with a hydrogel loading of 1.0 mg cm(-2). For the same hydrogel composition and loading, the current density on the MgOC-modified electrode was more than 30 times higher than that on a flat carbon electrode. On increasing the solution temperature to 45 °C, the catalytic current increased to 300 mA cm(-2), with a hydrogel loading of 1.6 mg cm(-2). Furthermore, the stability of the hydrogel electrode was improved by using the mesoporous carbon materials; more than 95% of the initial catalytic current remained after a 220-day storage test in 4 °C phosphate buffer, and 80% was observed after 7 days of continuous operation at 25 °C.

Characterization of Membrane-bound Spermidine Dehydrogenase ofCitrobacter freundii

Spermidine dehydrogenase found in the membrane fraction of Citrobacter freundii IFO 12681 was solubilized with Triton X-100 and further purified to homogeneity. The properties of the membrane enzyme were almost identical to those obtained from the soluble fraction of the organism with respect to molecular and catalytic properties. Thus, binding properties of the enzyme to the bacterial membrane were checked. The ratio of enzyme activity found in the soluble fraction to the membrane fraction was dependent on salt concentration during cell disruption. A hydrophobic interaction was largely involved in anchoring the enzyme to the membrane fraction. Purified spermidine dehydrogenase from the soluble fraction was readily adsorbed into the membrane fraction in the presence of salt. Spermidine dehydrogenase appeared to be a membrane-bound enzyme localized in the cytoplasmic membranes in a manner that makes a partial release of the enzyme possible during mechanical cell disruption. When spermidine oxidation was done with the resting cells of C. freundii, a stoichiometric formation of two reaction products, 1,3-diaminopropane and gamma-aminobutyraldeyde, was observed without any lag time. These facts indicate that the enzyme is localized on the outer surface of the cytoplasmic membranes or in the periplasmic space of the organism.

Preparation And Characterization Of Some Nickel 1,2-Dithiolene Complexes As Single-Component Semiconductors

The unsymmetrical (mixed-ligand) nickel 1,2-dithiolene complexes Ni(pddt)(dmio) and Ni(pddt)(dmit) (where pddt is 6,7-dihydro-5H-1,4-dithiepin-2,3-dithiolate, dmio is 1,3-dithiol-2-one- 4,5-dithiolate, and dmit is 1,3-dithiol-2-thione-4,5-dithiolate) were synthesized and characterized. The new complexes were found to be soluble in organic solvents, from which single crystals and/or thin deposits can be obtained. In the solid state, the compounds behave as single-component semiconductors with low room temperature conductivity values

RISK FACTORS FOR DISLOCATION OF THE ULNAR NERVE AFTER SIMPLE DECOMPRESSION FOR CUBITAL TUNNEL SYNDROME

Anterior dislocation of the ulnar nerve is occasionally encountered after simple decompression of the nerve for treatment of cubital tunnel syndrome. The purpose of this study was to determine whether the incidence of dislocation of the nerve following simple decompression of the nerve is correlated with the patient's preoperative characteristics and/or elbow morphology. We studied 51 patients with cubital tunnel syndrome who underwent surgery at our institution. Intraoperatively, we simulated dislocation of the nerve after simple decompression by flexing the elbow after releasing the nerve in each patient. Univariate and multiple logistic regression analysis showed that young age and a small ulnar nerve groove angle are positively correlated with dislocation of the nerve. Our results suggest that patients who are young and/or have a sharply angled ulnar nerve groove identified radiographically have a high probability of experiencing anterior dislocation of the ulnar nerve after simple decompression.

Small Indian mongooses and masked palm civets serve as new reservoirs of Bartonella henselae and potential sources of infection for humans

The prevalence and genetic properties of Bartonella species were investigated in small Indian mongooses and masked palm civets in Japan. Bartonella henselae, the causative agent of cat-scratch disease (CSD) was isolated from 15.9% (10/63) of the mongooses and 2.0% (1/50) of the masked palm civets, respectively. The bacteraemic level ranged from 3.0 × 10¹ to 8.9 × 10³ CFU/mL in mongooses and was 7.0 × 10³ CFU/mL in the masked palm civet. Multispacer typing (MST) analysis based on nine intergenic spacers resulted in the detection of five MST genotypes (MSTs 8, 14, 37, 58 and 59) for the isolates, which grouped in lineage 1 with MST genotypes of isolates from all CSD patients and most of the cats in Japan. It was also found that MST14 from the mongoose strains was the predominant genotype of cat and human strains. This is the first report on the isolation of B. henselae from small Indian mongooses and masked palm civets. The data obtained in the present study suggest that these animals serve as new reservoirs for B. henselae, and may play a role as potential sources of human infection.

Long-term follow-up of periarterial sympathectomy for chronic digital ischaemia

This study investigates long-term clinical results (> 10 years) of periarterial sympathectomy in chronic ischaemic digits compared with intermediate-term results (3 years). Periarterial sympathectomy via the palm and volar wrist was carried out on 11 hands of seven patients with digital ischaemia but no gangrene or severe ulceration. The aetiology of ischaemia was Buerger's disease in four hands, collagen disease in three hands, and repetitive digital trauma in four hands. Subjective symptoms were evaluated at a mean follow-up period of 12 years. The efficacy of surgery was assessed objectively using thermography and plethysmography. Although five of seven patients continued on oral vasodilators and antiplatelet agents until the final follow-up, improvement of symptoms was maintained in all patients between intermediate- and long-term evaluations. Our results suggest that periarterial sympathectomy via the palm and wrist could prevent long-term aggravation of symptoms of chronic digital ischaemia when combined with adequate postoperative drug therapy.

Reflux esophagitis after esophagectomy: impact of duodenogastroesophageal reflux

Reflux esophagitis (RE) is a known complication disturbing patients' quality of life after esophageal resection. It is generally recognized that bile reflux as well as acid reflux cause RE. However, the clinical influence of acid and bile reflux, and Helicobacter pylori (H. pylori) infection on RE in the cervical esophagus after esophagectomy is not yet clarified. Sixty patients who underwent cervical esophagogastrostomy following esophagectomy were enrolled in this study. They underwent examination for H. pylori infection, endoscopic examination, and continuous 24-hour pH and bilirubin monitoring, at 1 month after surgery. The influence of acid and/or bile reflux, H. pylori infection, and others on the development of RE were investigated. RE was observed in 19 patients (32%) at 1 month after esophagogastrostomy, mild RE in 16 (27%), and severe RE in 3 (5%). The percentage of time duration of both acid and bile reflux into the cervical esophagus was higher in patients with RE than in those without (P = 0.027, P < 0.001). A significant difference in %time pH < 4 acid reflux was found between mild RE and severe RE (P = 0.014), and a statistical difference in %time abs. > 0.14 between non-RE and mild RE (P = 0.017). Acid and/or bile reflux was observed in 31 patients (52%), acid-only reflux in 6 (10%), bile-only reflux in 15 (25%), and acid-and-bile reflux in 10 (17%). Severe RE was observed only in patients having acid-and-bile reflux. On the univariate analysis, no infection of H. pylori, acid reflux, and bile reflux were determined to be the influencing factors to RE among the clinical factors including age, gender, route of esophageal reconstruction, H. pylori infection, and acid-and-bile reflux. In the subanalysis using the logistic model, there were significant correlations between bile reflux and RE irrespective of the presence of H. pylori infection (P = 0.016, P = 0.007). On the other hand, there was a significant correlation between acid reflux and RE only in patients without H. pylori infection (P = 0.039). In the early period after esophagogastrostomy, bile reflux could cause RE irrespective of H. pylori infection, while acid reflex could cause RE only in patients without H. pylori infection. There is a possibility that bile reflux plays an important role in the development of RE after esophagectomy.