Effects of overexpansion on stents' recoil, symmetry/asymmetry, and neointimal hyperplasia in aortas of hypercholesterolemic rabbits.

BACKGROUND: It is not known whether overexpansion modifies stent recoil, symmetric distribution of struts, and neointimal hyperplasia. OBJECTIVES: The objectives were (a) to evaluate whether stent overexpansion modifies the geometric configuration of the stent in the arterial wall, (b) to determine the relationship between overexpansion and stent recoil, and (c) to evaluate the relationship between the distribution of struts and neointimal hyperplasia. METHODS: Twenty tubular stainless steel 316L stents (3.0 and 3.5 mm in diameter) were implanted at 20 and 10 atm, respectively, in the abdominal aorta of New Zealand rabbits fed a hypercholesterolemic diet (1% cholesterol). Sham operations were also performed in seven animals. Eight weeks after implantation or sham operation, an intravascular ultrasound (IVUS) study was performed to measure stent recoil and aid in stent classification (symmetric or asymmetric) according to strut distribution. The degree of injury and neointimal hyperplasia were also evaluated in hematoxylin-eosin stained sections. RESULTS: The symmetry/asymmetry of stents assessed by IVUS, as well as the neointimal hyperplasia, was similar in both groups. Stent recoil was significantly greater in the 3.0-mm stent (overexpanded) group (0.28+/-0.02 mm), as compared with stent recoil in the 3.5-mm stent group (0.10+/-0.01 mm, P<.05). The neointimal hyperplasia in histological slices, independent of the implant technique, was predominantly in zones with higher strut concentration as compared with zones with fewer struts. CONCLUSIONS: Stent overexpansion enhanced stent recoil and did not modify symmetric and asymmetric strut distribution. Neointimal hyperplasia was not modified by the implant technique. Interestingly, significant hyperplasia was observed in locations with greater strut concentration, independent of overexpansion.     

Porous Ti-6Al-4V alloy fabricated by spark plasma sintering for biomimetic surface modification

Porous compacts with both biological and biomechanical compatibilities and high strength were developed. Spherical powders of Ti-6Al-4V alloy, which were either as received or surface modified with the use of calcium ions by hydrothermal treatment (HTT), were fabricated by a spark plasma sintering process. The porous compacts of pure Ti were used as reference materials. Porosity was approximately 30%, and compressive strengths were 113 and 125 MPa for the as-received Ti alloy powders and those modified by the HTT process, respectively. The bending strength and elastic modulus of as-received Ti alloy powders were 128-178 MPa and 16-18 GPa, respectively. Each of the compacts was immersed in simulated body fluid (SBF). The amount of adsorption/precipitation of calcium phosphate through the compacts was measured by weight change and was observed by SEM. The compacts were covered with calcium phosphate after 2 weeks of immersion in SBF. The compacts of Ti alloy had plenty of precipitated apatite crystals, and modification by HTT accumulated more precipitation. Because calcium phosphate is a mineral component of bone, apatite, which is precipitated on the surface of the compacts, could adsorb proteins and/or drugs such as antibiotics. It is expected that a large amount of proteins and/or drugs could be impregnated when the porous compacts developed are used.     

COMPRI--an instrument to detect patients with complex care needs: results from a European study

The authors developed a screening instrument to detect patients in need of complex care coordination at admission to a general hospital. On the basis of a series of risk factors for care complexity, the authors constructed a short, care complexity prediction instrument (COMPRI) and assessed its qualities. The COMPRI is an easily administered screening instrument that detects patients at risk for complex care needs for whom care coordination is indicated. COMPRI's predictive power exceeds all currently available case-mix instruments.     

A novel isoform of the smooth muscle cell differentiation marker smoothelin

Studies on smooth muscle cell differentiation and those on vascular development in mouse and humans have long been hampered by the lack of suitable markers. Here we describe a novel, large isoform of smoothelin, a structural protein of differentiated, contractile smooth muscle cells. The protein, which is highly conserved in mouse and humans, shows homology with other cytoskeleton-associated smooth muscle cell proteins and contains an actinin-type actin-binding domain. Northern blot analysis from various mouse organs identified short and long smoothelin mRNA forms, which exhibit distinct tissue expression patterns. The short form is highly expressed in visceral muscle tissues such as intestine and stomach and is not detectable in brain, while the long mRNA form is expressed in all vascularized organs. These results may provide new tools and approaches to study both smooth muscle cell differentiation and proliferative vascular disease. Received: 25 August 1998 / Accepted: 19 October 1998     

The complete genome sequence of a new necrovirus isolated from <Emphasis Type="Italic">Olea europaea</Emphasis> L.

Summary. The complete nucleotide sequence of a virus isolated from Olea europaea L. (GP isolate), previously identified as an isolate of Tobacco necrosis virus D (TNV-D) based on its coat protein sequence, was determined. The viral RNA genome consists of 3683 nucleotides and contains five open reading frames. The putative RNA-dependent RNA polymerase shows 91.2% amino acid identity with that of an isolate of Olive latent virus 1 (OLV-1) and the coat protein reveals highest sequence identity with that of TNV-D. Based on the deduced genome organization and phylogenetic analysis of predicted functional translation products with that of other necroviruses, the GP isolate genome appears to represent an example of a new virus arisen by gene exchange and is proposed to be a new necrovirus, provisionally named Olive mild mosaic virus.     

Viral properties, primary structure and phylogenetic analysis of the coat protein of an Olive latent virus 1 isolate from Olea europaea L

An Olive latent virus 1 isolate designated GM6, obtained from a Portuguese olive tree, was characterized and the coat protein gene sequenced and analysed. The purified virus particles showed to be isometric with ca. 30 nm in diameter and contained a single-stranded RNA species with ca. 3.7 kb. The dsRNA profile obtained from infected tissues showed three major species with ca. 3.7, 1.5 and 1.3 kbp. SDS-PAGE analysis revealed a major peptide with an apparent molecular mass of 32 kDa identified as the coat protein. A viral genome region containing the coat protein gene was amplified by RT-PCR and the cDNA was cloned and sequenced. The coat protein gene revealed to be 813 nucleotides long and encode a peptide with 270 amino acid residues and an estimated Mr of 29,851. Alignment of the deduced amino acid sequence with that of other necroviruses showed a higher identity with OLV-1 tulip isolate (97.7%) than with OLV-1 citrus isolate (87.7%). The consensus pattern of the coat protein 'S' domain is conserved in GM6 isolate coat protein sequence, except in amino acid 151, leucine. This is the first report on the coat protein sequence of an OLV-1 olive isolate.     

Effect of pharmacological purging on natural killer cell number and activity in human bone marrow.

We assayed natural killer (NK) cell activity and phenotype from human bone marrow (BM) following "purge" with 4-hydroperoxycyclophosphamide (4HC) at 60 micrograms/ml for 30 min in vitro. In all cases studied, lytic activity against the K562 cell line was either significantly decreased or abolished following 4HC purge. Although NK activity was significantly affected by 4HC treatment, no major differences in the phenotype between the purged and unpurged population were seen. Further, while in vitro culture of BM with IL2 resulted in a significant increment of NK activity, no IL-2 responsive cells were found in the 4HC purged BM after 14 days of culture. This study demonstrates that pharmacological purging of bone marrow results in a persistent functional decline of NK cell activity and may serve as a useful model for the study of the ontogeny of NK cells.     

RPGRIP1s with distinct neuronal localization and biochemical properties associate selectively with RanBP2 in amacrine neurons

RPGR and RPGRIP1 are molecular partners with vital roles in retinal function. Mutations in RPGR are implicated in heterogeneous retinal phenotypes, while those in RPGRIP1 lead to Leber congenital amaurosis. RPGR and RPGRIP1s differentially localize in photoreceptors among species. This may contribute to phenotype disparities among species bearing mutations in RPGR. However, it cannot account for the phenotype heterogeneity associated with RPGR- and RPGRIP1-linked mutations in the human. The existence of RPGRIP1 isoforms with distinct cellular, subcellular localizations and biochemical properties in the retina is shown. High mass RPGRIP1 isoforms, p175/p150, enriched in the outer segment (OS) compartment of photoreceptors are identified. The remaining isoforms are present across subcellular fractions, including nuclei and are soluble. The p175/p150 are predominantly sequestered in the cytoskeleton-insoluble fraction of OS and nuclei. In selective amacrine cells, and in the transformed photoreceptor line, 661W, RPGRIP1s localize at restricted foci to nuclear pore complexes and/or the vicinity of these. Among the nucleoporins, RPGRIP1 isoforms selectively associate in vivo with RanBP2 (Nup358). RPGRIP1s also decorate microtubules in 661W cells and occasionally form coiled-like inclusion bodies in the perikarya. These results support distinct but complementary functions of RPGRIP1 isoforms in cytoskeletal-mediated processes in photoreceptors and amacrine neurons, and may explain the Leber phenotype linked to RPGRIP1 mutations in humans. Moreover, the data implicate a role of RanBP2 in the pathogenesis of neuro(retino)pathies and as a docking station to mediate the nucleocytoplasmic shuttling of RPGRIP1s and their interaction with other partners in amacrine and 661W neurons.