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A Sokoloff

Publications and source records attributed to A Sokoloff.

12 recordsLinked to original sources
PubMed2003

Risk factors of early and late complications in patients undergoing endovascular aneurysm repair.

OBJECTIVES: to identify pre-operative factors that could predict complications following from transluminal repair of abdominal aortic aneurysms (AAA). METHODS: during a 5-year period, 96 consecutive patients underwent elective endovascular treatment of a AAA. In all patients, helical CT and/or Magnetic Resonance Imaging (MRI), and plain abdominal roentgenogram were performed at 1, 3, 6, 12, 18, and 24 months and yearly thereafter. Angiography was performed systematically 1 year after the stent-graft implantation, or earlier if helical CT or MRI diagnosed an increase in the maximal transverse diameter or a high flow endoleak. RESULTS: early (<30 days) morbidity (12%) was significantly increased by pre-operative renal insufficiency (p < 0.01). Early mortality (2%) correlated with ASA score (p = 0.01). Median follow-up was 27 months (range 3-66). Mortality (12%) during follow-up was correlated to the pre-operative coronary status (p = 0.01). A type I endoleak was diagnosed in 18 patients (19%). Common iliac artery diameter was correlated with the presence of type I endoleak (p < 0.001). A type II endoleak was diagnosed in 47 (49%) patients. The diagnostic of type II endoleak was significantly increased (p = 0.001) in patients with pre-operative patent IMA associated with more than four patent lumbar arteries. The anatomic characteristics of the aneurysm were correlated to the additional endovascular procedures during stentgraft implantation (p = 0.01), and to the implantation of a complementary iliac limb extension during follow-up (p = 0.01). CONCLUSIONS: the risk factors determined by this statistical analysis could help surgeons to select more accurately patients suitable for endovascular treatment.

Aged↗
PubMed1998

Membrane fusion mediated by baculovirus gp64 involves assembly of stable gp64 trimers into multiprotein aggregates.

The baculovirus fusogenic activity depends on the low pH conformation of virally-encoded trimeric glycoprotein, gp64. We used two experimental approaches to investigate whether monomers, trimers, and/or higher order oligomers are functionally involved in gp64 fusion machine. First, dithiothreitol (DTT)- based reduction of intersubunit disulfides was found to reversibly inhibit fusion, as assayed by fluorescent probe redistribution between gp64-expressing and target cells (i.e., erythrocytes or Sf9 cells). This inhibition correlates with disappearance of gp64 trimers and appearance of dimers and monomers in SDS-PAGE. Thus, stable (i.e., with intact intersubunit disulfides) gp64 trimers, rather than independent monomers, drive fusion. Second, we established that merger of membranes is preceded by formation of large (greater than 2 MDa), short-lived gp64 complexes. These complexes were stabilized by cell-surface cross-linking and characterized by glycerol density gradient ultracentrifugation. The basic structural unit of the complexes is stable gp64 trimer. Although DTT-destabilized trimers were still capable of assuming the low pH conformation, they failed to form multimeric complexes. The fact that formation of these complexes correlated with fusion in timing, and was dependent on (a) low pH application, (b) stable gp64 trimers, and (c) cell-cell contacts, suggests that such multimeric complexes represent a fusion machine.

Animals↗
PubMed1994

The N-ethylmaleimide-sensitive protein thiol groups necessary for sea-urchin egg cortical-granule exocytosis are highly exposed to the medium and are required for triggering by Ca2+.

It is known that sea-urchin egg cortical-granule exocytosis is inhibited by agents such as N-ethylmaleimide (NEM) which modify thiol groups. The fusion-related proteins modified by these agents have yet to be identified, nor is there information regarding the topography of these thiol groups. Furthermore, the step in cortical-granule exocytosis at which these thiol groups participate is unknown. In this study we have investigated the topological properties of, and the temporal requirement for the function of, the fusion-related thiol groups by treating the isolated exocytotic apparatus with high-molecular-mass dextrans and BSA carrying thiol-reactive 3-(2-pyridyldithio)propionate groups. The dextran derivatives inhibited exocytosis. The BSA derivative was much less inhibitory. Inhibition was reversed by treatment with dithiothreitol. When NEM was added to the dextran-derivative-treated exocytotic apparatus, treatment with dithiothreitol completely reversed inhibition, indicating that the dextran derivatives inhibit by reacting at the NEM-sensitive sites. A pulse of Ca2+ applied in the presence of inhibitors did not trigger any fusion following the removal of the inhibitor by dithiothreitol. These data show that the thiol groups, the modification of which by NEM inhibits exocytosis, are exposed to the medium in terms of their accessibility to macromolecules. They also show that the fusion-related thiol groups are required during the Ca(2+)-dependent stage of exocytosis.

Animals↗
PubMed1993

Lysolipids reversibly inhibit Ca(2+)-, GTP- and pH-dependent fusion of biological membranes.

Membrane fusion in exocytosis, intracellular trafficking, and enveloped viral infection is thought to be mediated by specialized proteins acting to merge membrane lipid bilayers. We now show that one class of naturally-occurring phospholipids, lysolipids, inhibits fusion between cell membranes, organelles, and between organelles and plasma membrane. Inhibition was reversible, did not correlate with lysis, and could be attributed to the molecular shape of lysolipids rather than to any specific chemical moiety. Fusion was arrested at a stage preceding fusion pore formation. Our results are consistent with the hypothesis that biological fusion, irrespective of trigger, involves the formation of a highly bent intermediate between membranes, the fusion stalk.

Animals↗
PubMed1989

Musculotopic innervation of the primary flight muscles, the pectoralis (Pars thoracicus) and supracoracoideus, of the pigeon (Columba livia): a WGA-HRP Study.

The distribution of motoneurons innervating the primary depressor and elevator muscles of the wing of the domestic pigeon (Columba livia) was studied by using the retrograde axonal tracer lectin-conjugated horseradish peroxidase (WGA-HRP). Injection of WGA-HRP into the pectoralis (pars thoracicus) labeled neurons in the ventromedial corner of the lateral motor column of the spinal cord. These neurons were arranged in a column extending from spinal segment X or XI to spinal segment XII or XIII. The pectoralis, the primary depressor muscle of the wing, consists of two parts which are anatomically and functionally distinct, the sternobrachialis (SB) and thoracobrachialis (TB). Injection into the SB labeled neurons in the rostral and middle regions of the pectoralis motoneuron column. In contrast, injection into the TB labeled neurons in the middle and caudal regions of the pectoralis motoneuron column. Injection into the primary elevator muscle of the wing, the supracoracoideus, labeled neurons in the lateral motor column in spinal segments X and XI. These motoneurons were located dorsolateral to motoneurons labeled following pectoralis injection. These data demonstrate musculotopic segregation of the motoneurons innervating the primary flight muscles in the pigeon and, further, illustrate that the SB and TB subregions of the pectoralis are innervated by discrete aggregations of motoneurons.

Animals↗
PubMed1967

Tribolium castaneum: morphology of "aureate" revealed by the scanning electron microscope.

Counts of setae in "aureate" (au), spontaneous autosomal recessive mutation of good penetrance and viability, show that the au gene causes a three-fold increase in setation over the normal in the visible abdominal sternites but not in the membranous wings of the tenebrionid flour beetle Tribolium castaneum. Micrographs taken with the scanning electron microscope demonstrate that the au gene increases setation throughout the body.

Animals↗
PubMed1965

Odorous secretion of normal and mutant Tribolium confusum.

An autosomal recessive mutant characterized by "melanotic stink glands" has been found in the tene-brionid flour beetle, Tribolium confusum. The contents of the reservoirs of both pairs of odoriferous glands become modified in two ways as the beetles age. (i) The quinones (2-ethyl- and 2-methyl-1,4-benzoquinone) present in the secretion are reduced to 1/20 of that normally found in the wild type. (ii) The contents may be modified into a high-molecular-weight polymeric substance, which becomes visible through the exoskeleton and, upon dissection, appears as a black solid lump. The medium in densely populated cultures of the mutant becomes moldy while that containing normal beetles remains particulate. This difference suggests that one of the functions of the secretions of the odoriferous glands is to prevent the growth of fungi or bacteria in the nutrient flour.

Aging↗
PubMedDate not supplied

Horned gena, an atavistic sex-linked dominant mutation in Tribolium confusum.

Horned gena (Hg), a sex-linked dominant mutation with semilethal effects in the imago stage, was found in Tribolium confusion. The Hg mutant is characterized by a pair of horns of variable size and shape that arises from the genoclypeal suture in mildly expressed beetles or a more pronounced horn-like structure resulting from a folding of the genal shelf near the compound eyes. In these beetles there is considerable stress on the exoskeleton of the head so that the cranium is fragmented between the eyes, leaving large, irregularly shaped areas of the head unprotected by cranial exoskeleton. These beetles die presumably because of bacterial infection or because they cannot retain moisture within their bodies. This mutation differs from the mutation V-Grube found in another tenebrionid, Tenebrio molitor. Taxonomic, genetic, and cytological evidence is presented suggesting that Hg is a gene of ancient origin, having existed at least since the genera of Tenebrionidae were being evolved.

Animals↗