Adsorption of tetrakis(p-sulfonatophenyl)porphyrin on kaolinite

The surface modification of kaolinite to introduce the adsorption sites for anionic species was reported. The introduction of an anion exchange site was as follows; intercalation of 2-aminoethanol into kaolinite by using dimethyl sulfoxide-kaolinite intercalation compound as a precursor and subsequent hydrochlorination of 2-aminoethanol-kaolinite in 1,4-dioxane. The hydrochlorination of 2-aminoethanol-kaolinite was confirmed by the increase in the basal spacing (0.2 nm, corresponding to the diameter of chlorine) and the appearance of the infrared absorption bands due to ammonium groups. The modified kaolinite adsorbed an anionic dye, tetrakis(p-sulfonatophenyl)porphyrin, from a N,N-dimethylformamide solution. Initial slope of the adsorption isotherm of tetrakis(p-sulfonatophenyl)porphyrin on the hydrochlorinated 2-aminoethanol-kaolinite was steep, showing strong adsorbate-adsorbent interactions. The gallery height after the adsorption of tetrakis(p-sulfonatophenyl)porphyrin was close to the thickness of the porphyrin ring, suggesting that tetrakis(p-sulfonatophenyl)porphyrin was intercalated as a monomolecular layer and that chlorine simultaneously deintercalated.     

Inhibition of rat platelet aggregation by mycalolide-B, a novel inhibitor of actin polymerization with a different mechanism of action from cytochalasin-D

In vitro effects of mycalolide-B (MB), isolated from marine sponge, were investigated with regard to the activation of rat platelets. Collagen-induced platelet aggregation in platelet-rich plasma (PRP) was slightly but significantly potentiated by lower concentrations of MB (0.3 and 1 microM) but was inhibited by higher concentrations (3 and 10 microM). ADP-induced platelet aggregation in PRP was also significantly prevented by MB (1-10 microM). Potentiation of ADP-induced aggregation by MB (0.3 microM) was hardly observed. G-actin contents, determined by DNase I inhibition assay, were increased in resting washed platelets incubated with MB (3 microM). In contrast, cytochalasin-D (CD) at 3 microM slightly reduced G-actin contents in resting platelets. After platelet aggregation with collagen (3 microg/ml) or ADP (10 microM), G-actin contents in platelets were reduced, indicating de novo actin polymerization. MB (3 microM) and CD (3 microM) abolished both ADP (10 microM)- and collagen (3 microg/ml)-induced platelet aggregation and actin polymerization in washed platelets. MB (1-10 microM) had no effects on intracellular Ca2+ concentrations in ADP (10 microM)-stimulated platelets. [125I]-fibrinogen binding to activated platelets with ADP (10 microM)(was inhibited by MB (0.3-3 microM) in a concentration-dependent manner. Thrombin-induced platelet-fibrin clot retraction was inhibited by MB (1 and 10 microM). These results suggest that MB inhibits platelet activation by interfering with actin polymerization through a different mechanism of action from CD. MB may be a useful tool for studying the role of actin polymerization in various cells.     

Clinical application of a magneto-optical disk image filing system/image save and carry (ISAC) system.

We propose the utilization of portable magneto optical disks for image filing. The main problems in PACS are the need for a high-speed local area network (LAN) and a large mass storage device. An image filing system--image save and carry (ISAC)--is one solution for these problems in present PACS and requires minimal additional hardware and cost for the installation. Whenever a patient is examined, the clerk carries the medical record and the ISAC magneto-optical disk for recording image data, and after inspection records the image data into the magneto-optical disk. We investigated the number of image retrievals done for inpatients and outpatients in 1988 at our radiation therapy department. The data storage requirements were on the average 18.5 MB for outpatients and 173.9 MB for inpatients. An ISAC display console needs also an easy-to-use man/machine interface for specifying images and image display characteristics in order to realize the ISAC system.     

40 Gbit/s×35 ch (1.4 Tbit/s aggregate capacity) WDMtransmission over 85 km standard singlemode fibre

The first successful transmission of 35 channels each at 40 Gbit/s line rate (1.4 Tbit/s aggregate capacity) over 85 km of standard singlemode fibre is reported. Error-free transmission was achieved using a dispersion compensation technique     

Simultaneous optimization of wet granulation process involving factor of drug content dependency on granule size

Computer optimization technique was applied to the simultaneous optimization of wet granulation process by a high-speed mixer granulator. Four pharmaceutical properties, including yield, drug content uniformity, geometrical mean diameter of granules, and uniformity of granule size, were selected to evaluate the quality of the granules. In particular, dependence of drug content uniformity on granule size was investigated using two model drugs, ascorbic acid and ethenzamide. An appreciable dependence of ascorbic acid content on granule size was not observed in model formulations. On the other hand, ethenzamide was contained more in small-size granules, and its content was decreased with an increase in amounts of hydroxypropyl cellulose (HPC-L; used as a binder) and binder solution. These observations suggested that drug content uniformity is influenced not only by drug solubility in the binder solution, but also by the use of HPC-L. A simultaneous optimal point incorporating four pharmaceutical properties was obtained using the generalized distance function. The experimental values of the four response variables obtained in newly prepared granules were found to correspond well with the predicted values of both granules containing ascorbic acid and ethenzamide. These results suggested that computer optimization would benefit the wet granulation process even if drug content segregation was involved in the process. Further, data obtained from computer optimization, in particular the contour diagram, will be valuable in the process validation.     

Seroprevalence of infectious bursal disease virus in free-living wild birds in Japan

Serum samples collected from 739 free-living wild birds of 44 species from Gifu, Mie and Hyogo Prefectures in Japan during the period 1989 to 1997 were tested for antibodies to infectious bursal disease virus (IBDV) serotypes 1 and 2 by a virus neutralization test. Serological evidence of infection with serotypes 1 and 2 was found in 15 (2%) of the sera of 6 species and 36 (4.9%) of the sera of 11 species, respectively. Antibodies to IBDV were detected from both sedentary and migratory species. These findings suggest that free-living wild birds have an important role in the natural history of IBDV. These findings raise the possibility that the IBDV prevalent in the breeding grounds of these birds in other countries could be imported by the migratory species. This is the first report of an extensive serological survey of IBDV in wild birds.     

Preconditioning enhances myocardial resistance to postischaemic myocardial stunning via adenosine receptor activation

OBJECTIVE: The aim was to test a hypothesis that ischaemic preconditioning attenuates myocardial stunning via adenosine receptor activation. METHODS: Myocardial stunning was induced in male rabbits by a transient 5 or 10 min coronary artery occlusion, and alteration of regional systolic thickening fraction (TF) was measured by using an epicardial Doppler sensor before and after the regional ischaemia. Rabbits were either untreated, preconditioned with 1 min ischaemia, given 8-phenyltheophylline (8-PT, 10 mg.kg-1 intravenously), or given 8-PT plus 1 min ischaemic preconditioning. Preconditioning and 8-PT were given 5 min and 20 min before stunning the heart, respectively. RESULTS: Postischaemic recovery of the thickening fraction was significantly improved by preconditioning with 1 min ischaemia. TF (% baseline) after 10 min ischaemia/30 min reperfusion was 84.3(SEM 5.0)% in the preconditioned group, which was significantly higher than the value of 51.3(8.1)% in the control rabbits. Treatment with 8-PT alone did not significantly alter the recovery of TF from 10 min ischaemia [TF = 45.0(7.4)%,], but 8-PT treatment completely abolished the effect of 1 min preconditioning [TF = 51.3(6.4)%]. Attenuation of myocardial stunning by 1 min preconditioning was also observed when the stunning was induced by 5 min ischaemia [92.2(1.3)% in preconditioned group v 75.9(3.2)% in controls]. CONCLUSIONS: These findings suggest that preconditioning protects the myocardium against stunning through activation of the adenosine receptors.     

Development of a dissecting aneurysm on the vertebral artery immediately after occlusion of the contralateral vertebral artery: a case report

A 49 year old female presented with subarachnoid hemorrhage due to a ruptured dissecting aneurysm on the left vertebral artery (VA). Following an occlusion test, we performed proximal occlusion of the left VA with detachable balloons. However, a dissecting aneurysm on the right VA developed three weeks later. After an occlusion test had showed no change in cerebral blood flow, auditory brain stem response, or neurological status, proximal occlusion of the right VA was performed. The patient has returned to normal life without neurological deficits. Bilateral dissecting aneurysms of the VA are quite common, but de novo VA dissecting aneurysms or enlargement of such aneurysms after occlusion of contralateral VA are rare. This case suggests that hemodynamics stress may be a causal factor in the development of VA dissecting aneurysms. Careful pre- and post-operative neuroradiological examination of the contralateral VA are required in patients undergoing VA occlusion for dissecting aneurysms.