Ultrafine magnetic metal dispersed carbons prepared from anisotropic pitch and metal acetylacetonate complexes

Transition metal (Fe, Co or Ni) dispersed carbon composites were prepared using the mixtures of metal acetylacetonate complex as a source of metal particles and an anisotropic coal-tar pitch as a carbon matrix precursor by heat treatment at the temperatures up to 1000°C. Mixing of the metal complexes and the pitch by dissolving in quinoline permitted the notable fine dispersion of the complex in the pitch. Then the resulting mixtures were easily converted to the metal dispersed carbons by pyrolysis under an inert atmosphere. The appeared particles were Fe₃O₄/-Fe/Fe₃C, -Co or Ni when using the corresponding metal complex. Besides, their particle diameters were much less than 30 nm and distributed evenly throughout the carbon matrix. The magnetic properties of the metal dispersed carbons were evaluated with a vibrating sample magnetometer, and it was found that saturation magnetization and coercive force ranged from 1.03 × 10^–5 to 5.65 × 10^–5 Wb · m/kg and from 0.21 × 10⁴ to 3.06 × 10⁴ A/m, respectively.     

Fluorophotometric quantitation of oxidative stress in the retina in vivo

PURPOSE: To establish a new fluorophotometric method to quantitate oxidative stress in the retina in vivo with a hydrogen peroxide (H2O2)-sensitive fluorescent dye. METHODS: For in vitro fluorophotometric study, nonfluorescent 2',7'-dichlorofluorescein (DCFH) was incubated with H2O2 (10 pM to 100 nM), and the production of fluorescent 2',7'-dichlorofluorescein (DCF) was measured with fluorophotometric analysis. The inhibitory effect of catalase was also examined. For in vivo fluorophotometric study, rabbit eyes received vitrectomy and were perfused with 5 microM 2',7'-dichlorofluorescein diacetate (DCF-DA) or 2',7'-dichlorofluorescein diacetate (DCFH-DA). For oxidative stress, 300 microM H2O2 was infused after perfusion of DCFH-DA. Fluorophotometric measurements of the chorioretinal peak were performed. The eyes were enucleated for fluorescent microscopic examination to determine the localization of DCF fluorescence. RESULTS: H2O2 converted DCFH to DCF in a dose-dependent manner, which was inhibited by catalase dose dependently. In vivo fluorophotometric study showed DCF-DA and DCFH-DA caused production of 2006 +/- 274 picomole/ml (mean +/- SD, n = 5) and 8.35 +/- 1.11 picomole/ml (n = 5), respectively, in the chorioretinal peak. DCFH-DA with stimulation by H2O2 induced 30.7 +/- 13.1 (n = 4) picomole/ml DCF. Fluorescent microscopy showed DCF production in the retina was significant in the eye treated with DCF-DA and minimal in the eye treated with DCFH-DA. Moderate DCF production in the nerve fiber layer was observed in the eye treated with DCFH-DA and H2O2. CONCLUSIONS: This new fluorophotometric method with DCFH-DA may be useful in quantitatively evaluating oxidative stress in the retina in vivo.     

Estimation of conduction velocity distribution byregularized-least-squares method

A novel technique for estimating the distribution of the conduction velocity of peripheral nerve fibers is described in this paper. In order to overcome the sensitivity of present methods to noisy data, a regularized-least-squares (RLS) method with a smoothing constraint and a self-adaption of regularization parameter was adopted. The simulation results demonstrated that the improved technique maybe applied in clinical diagnosis because it yielded reliable and almost undistorted results even when the simulated data are severely contaminated by noise     

Characteristics of meso-carbon microbeads separated from pitch

Mesophase spherules separated by solvent fractionation from heat-treated coal-tar pitch and from heat-treated asphalt at 430°C are named “meso-carbon microbeads”. Characteristics of these mesophase microbeads were studied. The meso-carbon microbeads are classified into three types, type C, type M and type P, corresponding to the raw pitch materials. The chemical composition of type C and type M consists of high molecular weight aromatic hydrocarbons having short side chains of aliphatic hydrocarbons, and that of type P consists of small ring number aromatic hydrocarbons having long side chains of aliphatic hydrocarbons. The shapes of the meso-carbon microbeads are classified into lemon-like and spherical by their shape. The meso-carbon microbeads do not fuse or melt by heat-treatment. The graphitizability of heat-treated meso-carbon microbeads is not high. When the meso-carbon microbeads are heat-treated at 300–500°C in a medium of polynuclear aromatic hydrocarbons (anthracene, pyrene, chrysene and pitch) their behavior is similar to that of mesophase spherules in pitch. However, when the ratio of the meso-carbon microbeads to the polynuclear aromatic hydrocarbon was changed, the behavior of the microbeads was peculiar.     

The use of multimedia in patient care.

A personal computer based system was constructed to assess the use of various forms of information (multimedia) in patient record keeping. A patient's file with his records kept in a multimedia fashion was made by using the system. We describe the hardware and software construction of the system together with the results and the memory requirements of each type of media. Potential usage of the system in the future is discussed especially in connection with the Picture Archiving and Communications Systems (PACS).     

Evaluation of Novapath assay for direct detection in patient stool of Vero toxin and Vero toxin-producing Escherichia coli]

We evaluated two kits which detect either Verotoxin (Novapath EHEC) or EHEC O157 (Novapath O157) directly from stool specimens and compared with the result of PCR. The tests can be completed in 3 hrs. All fecal specimens from 18 healthy volunteers showed negative results with both kits and PCR. Specimens from patients of EHEC O157 outbreak in Okayama Prefecture and asymptomatic families of patients of outbreak in Sakai City of Japan were also analyzed. Fecal specimens from which EHEC O157 was isolated showed positive results with both kits and PCR. Some specimens which were culture negative showed positive results with either Novapath EHEC or Novapath O157 or both. The sensitivity of Novapath O157 was lower than PCR to detect O157 organisms but took shorter time to get result. Novapath EHEC showed very high sensitivity in detecting Vero toxin. These results suggest that Novapath EHEC especially can be used clinically for rapid diagnosis.     

Contribution of peripheral chemoreceptor drive in exercise hyperpnea in humans

The peripheral chemoreceptors play a dominant role in the respiratory compensation of lactic acidosis during heavy exercise of humans. Our object was to determine the contribution of peripheral chemoreceptors to exercise hyperpnea during mild to moderate and heavy exercise above the anaerobic threshold. We used a hyperoxic suppression test in six normal male subjects. Inspired gas was abruptly changed without the subject's knowledge from air to pure oxygen for 5 to 6 breaths. The maximal ventilatory depression after O2 breathing was 5.5 +/- 1.7 L/min (BTPS) at mild exercise, and the depression increased with increasing exercise intensity up to 12.8 +/- 4.1 L/min (BTPS). The relative contribution of the peripheral chemoreceptors to ventilation in terms of percentage of the maximal ventilatory depression was maintained, being 20% throughout the entire work ranges studied. The contribution of the peripheral chemoreceptors to total ventilation is hardly altered by lactic acidosis caused by heavy exercise above the anaerobic threshold according to our data. These results suggested that the peripheral chemoreceptors may not be solely responsible for excessive hyperventilation, or residual activities of peripheral chemoreceptors still exist after O2 breathing especially during heavy exercise above the anaerobic threshold.     

Case report: intrahepatic cholangiocarcinoma with rhabdoid transformation

Sarcomatous transformation is found in approximately 5% of patients with intrahepatic cholangiocarcinoma. According to previous reports, sarcomatous cholangiocarcinomas are composed of spindle-shaped cells and/or multinucleated giant cells. Usually, vimentin is expressed by these sarcomatoid cells. We report a case of intrahepatic cholangiocarcinoma with an element of rhabdoid cells that occurred in a 61-year-old woman admitted for back pain. Various imaging techniques demonstrated multiple liver masses. Histologically, these tumours formed in both sarcomatous and ordinary tubular adenocarcinomatous areas. The sarcomatoid areas were occupied mainly by loosely arranged, eosinophilic rhabdoid cells, which expressed both keratin and vimentin. These findings suggest that rhabdoid cells may occur in an undifferentiated stage of cholangiocarcinoma and possess a strong tendency to metastasize.     

Distribution of plasmalemmal Ca(2+)-pump and caveolin in the corneal epithelium during the wound healing process

PURPOSE: Caveolae are small plasmalemmal invaginations which are assumed to play various physiological functions. In the present study, distribution of two caveolae-specific proteins, the plasmalemmal Ca(2+)-pump and caveolin, was examined in the corneal epithelium in the normal state and after artificial wounding. METHODS: A central epithelial ablation was made in the mouse cornea by a razor blade. After various intervals, the corneas were excised, fixed, and rapidly frozen. The specimens were subjected to immunofluorescence microscopy and immunoelectron microscopy, using antibodies against the plasmalemmal Ca(2+)-pump or caveolin. RESULTS: In the normal corneal epithelium, both plasmalemmal Ca(2+)-pump and caveolin were observed along the cell surface by immunofluorescence microscopy, and were localized to caveolae by immunogold electron microscopy. In the regenerating epithelium, 12-18 h after injury, plasmalemmal Ca(2+)-pump was seen as many dots in the cytoplasm by immunofluorescence microscopy; in contrast, caveolin persisted along the cell surface. Immunoelectron microscopy revealed that the labeling for the plasmalemmal Ca(2+)-pump was located around membranous structures in the cytoplasm and was scarce along the plasma membrane, while caveolin remained in caveolae. The Ca(2+)-pump regained normal distribution when the wound was closed. By quantitation in electron micrographs, the number of caveolae per unit plasma membrane length was found to be decreased in the wounded corneal epithelium. CONCLUSIONS: The present results indicate that caveolae undergo compositional modification during the wound healing process of the corneal epithelium. Considering putative caveolar functions, the phenomenon may be related to possible fluctuations of the intracellular Ca(2+)-concentration in the regenerating epithelium.