Access-Site Complications in Mechanical Thrombectomy for Acute Ischemic Stroke: A Review of Prospective Trials.

BACKGROUND: A shift has occurred in interventional cardiology from transfemoral to transradial access due to a 70%-80% decrease in complications. This shift has not yet taken place in other interventional specialties, perhaps owing to the lack of generalizability of findings in the cardiology data. PURPOSE: Our aim was to assess data from the recent mechanical thrombectomy prospective trials to better understand the access-site complication rate. DATA SOURCES: Articles were systematically sourced from the National Center for Biotechnology Information PubMed archive. STUDY SELECTION: According to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, prospective, randomized controlled trials published after 2008 with mention of major and/or minor femoral access-site complications in neuroendovascular mechanical thrombectomies were included. DATA ANALYSIS: Major and minor femoral access-site complications were extracted. A total complication rate was calculated with major access-site complications alone and combined with minor access-site complications. DATA SYNTHESIS: Seven prospective studies of 339 total screened met the inclusion criteria. Eleven major access-site complications were identified in of 660 total interventions, revealing a major access-site complication rate of 1.67% for patients undergoing mechanical thrombectomy with transfemoral access. If minor access-site complications were included, 35 total incidents were detected in 763 interventions, resulting in a total complication rate of 4.59%. LIMITATIONS: Multiple unspecified vessel and procedure-related complications were mentioned in the studies. CONCLUSIONS: The overall rate of major access-site complications was 1.67% in this review, which is not low and poses a risk to patients. We suggest further investigation into the feasibility and complication rates of alternative access sites for neurointerventional procedures.

Detection of human immunodeficiency virus type 1 after infection of unstimulated peripheral blood mononuclear cells.

Application of a highly sensitive PCR-based reverse transcriptase (RT) assay to the analysis of the infection of CD4+ cell lines with human immunodeficiency virus type 1 (HIV-1) demonstrated that virus production can be detected as early as 24 h after infection. Most of the signal at 24 h was due to virus production, as it could be substantially reduced by prior treatment with the RT inhibitor zidovudine. Virus production at 24 and 48 h was unaffected by the protease inhibitor indinavir. Infection of unstimulated peripheral blood mononuclear cells (PBMC) with a macrophage-tropic HIV-1 isolate yielded increasing virus production for 2-3 weeks, while infection with a T-cell line-tropic isolate yielded only low and sporadic virus production. Productive infection of unstimulated PBMC by the macrophage-tropic virus required functional Gag matrix and Vpr proteins; therefore, the monocyte-derived macrophage is probably the virus-producing cell in these cultures.

A broad cytotoxic T lymphocyte response to influenza type B virus presented by multiple HLA molecules.

The HLA restriction and epitope specificity of cytotoxic T lymphocytes (CTL) involved in recovery from influenza type B infection have not been extensively characterized. Here lymphocytes obtained from a healthy individual contained virus-specific CTL restricted by class I HLA molecules, HLA-A1, A2, B7 and B8, and the class II HLA molecules, HLA-DR1 and DR3. Four conserved viral epitopes were predicted from allele-specific motifs for peptides interacting with HLA-B8 and HLA-DR1. Bulk CTL recognized three 9mer HLA-B8-restricted peptides from nucleoprotein, residues 30-38, 263-271 and 413-421, and a 13mer HLA-DR1-restricted peptide from hemagglutinin, residues 308-320. The epitopes presented by HLA-A1, HLA-B7 and HLA-DR3 remain undefined. Peptide-specific CTL lines recognized influenza type B virus-infected cells indicating the peptides are representative of naturally processed epitopes. A hemagglutinin peptide-specific CD4 CTL clone expressed approximately 200 molecules of perforin mRNA/cell, suggestive of a functional perforin pathway for target cell lysis. The results indicate a broad CTL response composed of both CD8 CTL and CD4 CTL recognizing viral epitopes presented by multiple HLA molecules.

Human serum-sensitive Trypanosoma brucei rhodesiense: a comparison with serologically identical human serum-resistant clones.

Trypanosoma brucei rhodesiense clones, which are susceptible to lysis by normal human serum, were isolated from 3 different human serum-resistant clones originally derived from strain ETat 1.10. Serologically, these pairs of serum-sensitive and serum-resistant clones displayed the same variant surface glycoprotein (VSG) on their surface. Acquisition of human serum sensitivity correlated with susceptibility to lysis by human high density lipoprotein, a trypanocidal factor in normal human serum. Analysis of these paired populations by two-dimensional gel electrophoresis of whole trypanosomes and various subcellular fractions failed to reveal any differences in mobility of VSG and other proteins. Northern blot analysis of mRNAs from serum-sensitive and serum-resistant clones showed no differences when probed with a previously described resistance-specific probe. In addition, the ethanolamine membrane transport system and the overall membrane lipid fluidity did not reveal any detectable biochemical or biophysical differences in membrane properties. If resistance to lysis is indeed mediated by membrane changes at the enzymatic or structural level, the data presented suggest that the gene product(s) responsible for this change in human serum sensitivity may be present in very small quantities.

Failure of immunization with trypanosome endocytotic vesicle membrane proteins to provide nonvariant immunoprotection against Trypanosoma brucei.

Purified trypanosome endocytotic vesicles were subjected to Triton X-114 phase separation to obtain a fraction enriched in putative parasite receptors for adsorptive endocytosis. Rabbits immunized with this material produced antibodies that recognized many parasite proteins, including nonvarying epitopes on the parasite's endocytotic surface, the flagellar pocket membrane, as well as on membranes of endosomes and lysosome-like structures. These antibodies were unable to stimulate in vitro complement-mediated lysis of trypanosomes, and in an in vitro test of parasite growth inhibition they actually marginally enhanced parasite proliferation. No effect was observed on the parasite prepatent period or parasitemia in mice injected with antibody purified from the rabbit antisera, but their survival with the infection was significantly shortened. Finally, little difference was detected in parasitologic or hematologic parameters between immunized and control rabbits upon challenge with T. brucei infection.

Glycosome-associated tyrosine-phosphorylated protein in Trypanosoma brucei.

Phosphorylation of protein at tyrosine residues is an important mechanism for regulating protein function in eukaryotic cells. In this report we have identified by immunoblotting the target for tyrosine phosphorylation in the protozoan parasite Trypanosoma brucei as a doublet band of protein with molecular masses of 200 and 220 kDa. Ultrastructurally, the tyrosine-phosphorylated protein was localized to the microbody-like organelles unique to kinetoplastid protozoa, called glycosomes. Inhibition of multiplication by the tyrosine kinase inhibitor genistein appeared to have very different kinetics in procyclic and blood-stream stage parasites. This is consistent with a glycosomal location for the target of tyrosine kinase as these life cycle stages differ substantially in their dependence on glycolysis which occurs in this organelle.

Canine IgA glomerulonephropathy.

Three young intact male dogs housed together in a canine blood donor facility developed immune complex glomerulonephropathy within 2 years of each other. All three had membranoproliferative glomerulonephritis with varying clinical presentation and progression. Two dogs had subendothelial, and one dog subepithelial, electron microscopic dense deposits. Immunoperoxidase staining indicated that the primary antibody involved in the glomerular disease of these three dogs was IgA. The nature of the electron dense deposits was further studied by eluting and identifying immunoglobulin from affected kidneys of one dog. The primary antibody identified had a molecular weight greater than 300,000 Da and was determined to be IgA. Although IgA glomerulonephropathy is a common cause of glomerular disease in humans, this study represents the first documentation of the clinical syndrome of IgA glomerulonephropathy in the dog.

Analysis of host components in hydatid cyst fluid and immunoblot diagnosis of human Echinococcus granulosus infection.

To improve serodiagnosis of cystic hydatidosis, immunoblotting studies were performed to look for a highly specific parasite antigen(s). First, commercially available hydatid cyst fluid antigen preparations were characterized by SDS-PAGE and by immunoblotting with sera specific for parasite and host animal proteins. One preparation, designed for use in complement fixation tests, did not appear to be suitable for immunoblotting because of the low concentrations of parasite antigens. Several host proteins, including serum albumin and IgG, were detected in the cyst fluid. Sera from patients with Echinococcus granulosus infections and other parasitic diseases were examined by immunoblotting for antibodies against specific cyst fluid parasite antigens. Several parasite antigens were variably recognized. Only one antigen, a 40 kDa protein, was recognized by all E. granulosus-infected patients. Reactivity against this antigen was also observed in all sera from E. multilocularis, cysticercosis, and schistosomiasis patients as well as in some filariasis cases. Two E. granulosus antigens, molecules of 12.5 and approximately 17 kDa, were only recognized by antibodies from some E. granulosus patients.

Identification of an acute-phase reactant in murine infections with Trypanosoma brucei.

A 42-kDa protein appeared at a much higher concentration in plasma from Trypanosoma brucei-resistant (C57BL/6) mice after infection than in plasma from trypanosome-susceptible (C3H/He) mice. This protein was purified by sequential steps of gel filtration, protein A-Sepharose affinity chromatography, isoelectric focusing, and ammonium sulfate precipitation. The purified protein was identified as a subunit of the acute-phase reactant haptoglobin. Causes of elevated plasma haptoglobin and its implications for resistance to trypanosomiasis are discussed.

Evidence of tyrosine kinase activity in the protozoan parasite Trypanosoma brucei.

Phosphorylation of proteins at tyrosine is an important mechanism for regulating cell growth and proliferation in metazoan organisms. In this report, we have demonstrated that Trypanosoma brucei, a protozoan parasite, possesses a tyrosine kinase that plays a role in regulation of proliferation of this protozoan. Genistein, a tyrosine kinase inhibitor, prevented multiplication of the parasite. An in vitro kinase assay demonstrated the presence of a kinase capable of phosphorylating an exogenous substrate at tyrosine, and genistein was able to reduce trypanosome-mediated phosphorylation of this substrate. An alkali digestion of 32P-labeled trypanosome proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated several proteins phosphorylated at tyrosine. These results indicate that T. brucei has a tyrosine kinase that is involved in proliferation or growth regulation of the parasite and provide further evidence for the possibility of growth factor regulation and signal transduction in trypanosomes.

Trypanosoma brucei: a membrane-associated protein in coated endocytotic vesicles.

Membrane proteins were isolated from purified Trypanosoma brucei coated endocytotic vesicles by phase separation with Triton X-114. The largest abundant membrane protein was a doublet band with a molecular mass of about 77 kDa. A specific antiserum was prepared against this protein by immunization with antigen bands excised from sodium dodecyl sulfate-polyacrylamide gels. Immunoblot analyses with this antiserum showed that the 77-kDa protein was present in other T. brucei, in T. congolense, and in T. vivax bloodstream-stage parasites but absent from procyclic (tsetse fly midgut)-stage trypanosomes. Antigenically related molecules of 58, 300, and 15.5 kDa were also detected. The 300- and 15.5-kDa molecules were not in purified coated vesicles; they were detected in whole bloodstream- and procyclic-form T. brucei organisms. Immunofluorescent studies localized the antigen to the region between the flagellar pocket and the nucleus of bloodstream-form parasites. Ultrastructurally, the antigen was detected on membranes of endosomes and lysosome-like structures that contained endocytosed markers.

Coated vesicles from the protozoan parasite Trypanosoma brucei: purification and characterization.

A procedure was developed to purify a coated vesicle fraction from the protozoan parasite Trypanosoma brucei. Electron microscopy revealed a difference between T. brucei coated vesicles and clathrin-coated vesicles from other eukaryotes: trypanosome vesicles were larger (100 to 150 nm in diameter) and contained an inner coat of electron-dense material in addition to the external coat. Evidence suggests that the internal coat is the parasite's variant surface glycoprotein (VSG) coat. The SDS-PAGE analysis shows the major protein of T. brucei coated vesicles has a molecular mass of 61 kD, similar to VSG; this protein was recognized in an immunoblot by anti-VSG serum. Trypanosome coated vesicles also contain a protein which comigrates with the major protein (clathrin) of coated vesicles purified from rat brains. However, this protein is a minor component and it is not serologically cross-reactive with mammalian clathrin. Immunoblot analysis demonstrated that the parasite vesicles contained host IgG, IgM, and serum albumin.

Analysis of Propionibacterium acnes-induced non-specific immunity to Trypanosoma brucei in mice.

Mice treated with dead Propionibacterium acnes (previously called Corynebacterium parvum), up to 30 days before infection with any of three strains of Trypanosoma brucei, were more able to limit the level of first-wave parasitaemia than untreated controls. Reduced parasitaemia was not due to enhanced phagocytosis of input parasites and was associated with a dramatic reduction in the proportion of multiplying T. brucei in the blood of treated as compared to control mice. For 4 days after P. acnes treatment, T. brucei growth-inhibitory molecules, assayed by their effect on T. brucei multiplication under axenic culture conditions, were detected in the serum of recipient mice. The molecules were released by macrophages collected from the peritoneal cavity of P. acnes-treated mice, and similar molecules were produced in vitro by macrophages from normal mice after incubation with P. acnes. Accessory studies suggested that the molecules were breakdown products of P. acnes and were unlikely to be responsible for the long-term in-vivo effects of the P. acnes treatment. It was also shown that monokines and lymphokines which are likely to be induced by in-vivo P. acnes treatment, i.e. IL-1, IL-2, TNF alpha, INF alpha, INF beta, INF gamma, PGE1, PGE2, PGF2 alpha and biological mediators present in Con-A and LPS-induced spleen cell supernatants (collected 20, 40, 60 or 80 h after mitogen stimulation) had no influence on T. brucei growth under axenic culture conditions over a wide range of concentrations. The studies suggest that the P. acnes effect was not due to a direct interaction of these biological mediators with the T. brucei. We suggest that the reduction in T. brucei parasitaemia in P. acnes-treated mice reflects secondary physiological effects of one or more unidentified biological mediators.

Acquired resistance to ixodid ticks induced by tick cement antigen.

Antisera from guinea pigs made resistant to infestation with an ixodid tick of east and central Africa, Rhipicephalus appendiculatus, were used to identify the tick antigens they recognized by immunoblotting. Most of the antigens were found in tick salivary glands and in tick attachment cement. Antisera from R. appendiculatus-resistant guinea pigs also recognized some salivary-gland antigens in ticks of other species (R. pulchellus, R. evertsi, Amblyomma variegatum and A. gemma). Antibodies against the most strongly recognized R. appendiculatus antigen, a 20-kDa molecule, were only poorly reactive with similar-sized molecules in the other ticks. A 94-kDa antigen, which appeared to have broader cross-reactivity, was purified from R. appendiculatus attachment cement, and a monospecific rabbit serum was raised against it. This antiserum clearly recognized a molecule of similar molecular weight in R. pulchellus and R. evertsi. Intravenous inoculation of rabbits with the purified molecule elicited delayed-type hypersensitivity to the antigen. The hypersensitive rabbits demonstrated resistance to feeding of R. appendiculatus ticks but slight enhanced feeding of R. pulchellus ticks. These results are discussed with respect to their relevance for artificial induction of tick-feeding resistance.

Biochemical characterization of activation-associated bovine class I major histocompatibility complex antigens.

Utilizing a 'sandwich' ELISA assay we have been able to demonstrate that mAb W6/32, B1G6 and IL-A19 are reactive with three different monomorphic determinants on bovine class I major histocompatibility complex (MHC) molecules. Sequential immunoprecipitations performed with the mAb revealed that class I molecules on PBM comprise a single population with respect to reactivity with the mAb in that the beta 2m-associated proteins bear all three epitopes. By contrast, TCGF-driven lymphoblasts and cells transformed by Theileria parva (Tp) additionally express molecules of Mr 45000 bound to beta 2m which are recognized by mAb B1G6 and IL-A19 but not by W6/32. These two subclasses of molecules were further distinguished on the basis that, when tunicamycin was added to cultures in the preparation of cells for analysis, mAb W6/32 precipitated class I heavy chains of Mr 39000 while the extra molecules detected only by mAb B1G6 and IL-A19 were of Mr 37000 and 39000. On thymocytes, the mAb W6/32-non-reactive class I molecules are present in low amounts and are expressed by cells in the medulla area, unlike BoT1 (analogous to human CD1) molecules which are expressed by the cortical cells. Our studies also revealed that the supposed beta 2m-specific mAb B1G6 does not recognize the beta 2m-associated molecules (BoT1) precipitated by mAb TH97A and thus the specificity of mAb B1G6 in cattle is for an epitope on bovine beta 2m which is strongly influenced by the nature of the heavy chain with which the beta 2m is associated.

Elimination of the detection of an artefactual 65 kDa keratin band from immunoblots.

Contamination of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) samples with skin keratin has produced a recurrent problem of artefactual bands when highly sensitive detection methods, such as silver staining, have been used. Such an artefact also can be a problem in immunoblots because some sera appear to contain antibodies that react with a human skin keratin. A simple method for the removal of these antibodies with keratin immobilized on an affinity chromatography substrate is described.

A simple method for the production of specific antiserum to protein encoded in cloned genes. Immunization with precipitin lines.

A simple technique for raising specific antisera to protein encoded by cloned genes is described. The procedure involves preparation of an antiserum to Escherichia coli beta-galactosidase and the use of that serum to immunoprecipitate a fusion protein in a crossed immunoelectrophoresis gel followed by immunization with fusion protein precipitin arcs. An antiserum was prepared against protein encoded by an open reading frame in a dispersed repeated DNA sequence found in the protozoan Trypanosoma brucei. This serum recognized a polypeptide doublet of 33.5 and 32.5 kDa on immunoblots prepared from extracts of T. brucei. The method described should be applicable to other investigations where an immunochemical reagent against protein encoded by a cloned gene is desired.