Coexistent coronary and cerebrovascular disease: a place for carotid stenting.
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Aged↗
Biomedical subjects
J Theron
Publications and source records attributed to J Theron.
Towards a molecular phototyping system for allelic variants of MICA, encoded by polymorphisms in exons 2, 3 and 4 of MHC class I chain-related genes.
In this study we have developed a polymerase chain reaction-sequence-specific primer (PCR-SSP) or phototyping system to analyse the polymorphism of the human MICA gene locus. By scrutinising the reported MICA sequence variations in exons 2, 3 and 4 which encode the extracellular protein domains, we have selected and tested 20 MICA-specific primer mixes that should discriminate between the majority of homozygous and heterozygous combinations of MICA alleles 001-016. We have tested this scheme on DNA prepared from a large number of well-characterised tissue culture cell lines with previously reported MICA nucleotide sequences and found an excellent correlation with the observed PCR-SSP phototypes. We believe that this scheme can also be modified to detect new MICA alleles when they are characterised, as well as be incorporated into standard phototyping protocols to generate allele and haplotype profiles of both classical and non-classical HLA gene loci in test DNA samples.
Alleles↗
Non-penetrating subclavian artery trauma: management by selective transluminally placed stent device.
Non-penetrating injury to the subclavian artery has not often been reported. The limited experience of surgeons with this type of trauma and the difficult vascular control required for its management make it a surgical challenge. We report on two cases, one after blunt trauma and the other with a subclavian artery aneurysm following anterior dislocation of the shoulder. Percutaneous stent implantation in the subclavian artery was successfully performed with, in the second case, coil embolization of the aneurysm. Follow-up Doppler sonography and angiogram demonstrated patency and luminal integrity of the involved artery. This less invasive procedure may be a significant advance and a new approach in the conservative management of traumatic subclavian injury for selected cases.
Aged↗
False aneurysm of the internal carotid artery in Behçet's disease: successful combined endovascular treatment with stent and coils.
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Aneurysm, False↗
The occurrence of Theileria and Cowdria parasites in African buffalo (Syncerus caffer) and their associated Amblyomma hebraeum ticks.
The polymerase chain reaction and oligonucleotide probing were used to detect Theileria and Cowdria species in DNA extracted from blood and ticks recovered from 24 African buffalo during a gamecapture operation in the Kruger National Park, South Africa. Species-specific probing indicated that all but one of the buffalo were carrying at least one Theileria species. Indirect fluorescent antibody (IFA) serology indicated that all animals had been exposed to Theileria parva infection but only 33% were positive for T. parva by probing. Twelve (50%) of the animals but only six of the 214 adult Amblyomma hebraeum ticks examined (2.8%) were probe-positive for Cowdria. Only one Cowdria 16S genotype was detected in the animals and ticks.
Animals↗
Complications of carotid angioplasty and stenting.
The authors report the complications that occurred in their experience with performing recanalization procedures in the internal carotid artery and present their treatment strategies. The complications can be classified into those that were periprocedural and those that were postprocedural. The former include complications related to the vascular-approach access site of and those associated with the dilation and stenting procedure. Other complications observed included embolic events, dissection, vascular spasm, bradycardia, inappropriate dilation, occlusion of the external carotid artery, and rare, unusual complications such as the occurrence of iatrogenic cavernous carotid fistula. Postprocedure complications occurred in the hours and days following the procedure in the form of embolic and occlusive events, and hypotension and bradycardia were seen as late complications in the months following the procedure. The authors discuss how such complications occur and provide suggestions on how to avoid them. The role of stent placement and the potential use of protective devices are explored. Overall, adequate use of currently available systems allows for safe application of endovascular treatment techniques that avoid altogether or treat these potential complications. A reduced incidence of complications related to the initial individual learning curve may be obtained with preclinical training, in which use of invitro models should be considered. Surgical standby no longer seems required; however, early posttreatment surveillance in intensive care unit is mandatory to avoid the remaining primary complications.
Journal Article↗
Endovascular treatment of a traumatic subclavian artery aneurysm.
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Accidental Falls↗
Stable protein-RNA interaction involves the terminal domains of bluetongue virus mRNA, but not the terminally conserved sequences.
The interaction of bluetongue virus (BTV) proteins with viral RNA was investigated in vitro by means of a biochemical approach. By subjecting cytoplasmic extracts from virus-infected baby hamster kidney cells and in vitro synthesized radiolabeled RNA to ultraviolet cross-linking assays, we demonstrated that, of all the BTV proteins, NS2 becomes most intimately associated with the labeled viral RNA. Competition binding studies indicated that NS2 has the greatest affinity for the 3' region of the viral transcripts. By analyzing the binding efficiency of NS2 to mutant RNA transcripts which lacked the fully conserved 5'- and/or 3'-terminal hexanucleotides, we have established that these sequences are not necessary for optimal binding. The specificity of the NS2-RNA interaction was investigated by competition experiments with unlabeled BTV-specific homologous and heterologous competitor RNAs as well as with viral double-stranded RNA (dsRNA). Although apparent differences in the ability of NS2 to bind to the different RNA transcripts were observed, it did not bind to the dsRNA.
Animals↗
Asymptomatic carotid stenosis in patients undergoing major cardiac surgery: can percutaneous carotid angioplasty be an alternative?
OBJECTIVE: As the mortality associated with coronary artery bypass grafts has fallen, morbidity has become an increasing problem. The improvement of transluminal carotid angioplasty is enlarged to patients with asymptomatic severe carotid stenosis (> 85%) requiring coronary surgery. METHODS: Between January 1993 and January 1995, 10 patients underwent percutaneous carotid angioplasty prior to cardiac surgery (17.4 days). Mean age was 71 +/- 4.3 years. Four patients showed a contralateral occlusion of the internal carotid artery. Transluminal carotid angioplasty was carried out with a triple coaxial catheter system. Six angioplasties required a Strecker stent. RESULTS: Mean follow-up was 11.4 months. No mortality was observed. Only one patient showed a transient hemianopsia. All patients underwent angiography at four months. Two patients required a new procedure of carotid angioplasty completed with a Strecker stent in one case and by dilatation of a stent in another patient. CONCLUSION: The results of transluminal carotid angioplasty, in this short series, are encouraging in this group of high-risk morbidity and mortality (elderly patients, bilateral carotid lesions, multiple coronary arterial grafts).
Aged↗
Site-specific mutations in the NS2 protein of epizootic haemorrhagic disease virus markedly affect the formation of cytoplasmic inclusion bodies.
The importance of a conserved amino acid motif in the nonstructural protein NS2 of different orbiviruses was investigated with regard to virus inclusion body (VIB) formation. A number of epizootic haemorrhagic disease virus NS2 deletion and substitution mutants were prepared and expressed as baculovirus recombinants. Deletion of the motif or substitution of at least three residues within the region, had a detrimental effect on VIB formation in insect cells. Furthermore, these NS2 mutants were not complexed with single-stranded RNA in infected cells and appeared to be cytotoxic. Cumulatively, the results suggest that this motif is an essential structural determinant for NS2 function.
Amino Acid Sequence↗
Identification of a short domain within the non-structural protein NS2 of epizootic haemorrhagic disease virus that is important for single strand RNA-binding activity.
The role that a conserved amino acid motif, found in the non-structural protein NS2 of orbiviruses, plays in the interaction of this protein with single stranded (ss) RNA was investigated by mutation analysis of the NS2 of epizootic haemorrhagic disease virus. An NS2 mutant in which this motif (amino acids 75 to 83) was deleted was expressed in Spodoptera frugiperda cells by a recombinant baculovirus and found to be unable to bind to poly(U)-Sepharose. The deletion mutant also differed from wild-type NS2 in that it did not appear to be complexed with ssRNA in cells infected with the baculovirus recombinant. Furthermore, the deletion exerted an adverse effect on the ability of NS2 to form inclusion bodies in the cytoplasm of baculovirus-infected insect cells. To further characterize the role of this motif in RNA-binding, specific residues within the region were substituted by site-directed mutagenesis and the mutants were expressed in Escherichia coli as fusion proteins. Analysis of the different mutant proteins indicated that in each case ssRNA-binding was impaired relative to that of the wild-type NS2 control. The degree of impairment corresponded to the number of amino acid substitutions and the largest effects were associated with non-conserved substitutions. It is suggested that the conserved motif is an important structural determinant in the interaction of NS2 with ssRNA.
Amino Acid Sequence↗
[Acute carotid occlusion: thrombolytic treatment].
The occurrence of a neurologic deficit at the time of an acute obstruction of the internal carotid does not equate with neurons death. The size of the residual infarct depend on the duration and the depth of ischemia. The goal of fibrinolytic therapy is to obtain a fast reperfusin of the ischemic areas to limit the size of the residual infarct. The risk of reperfusion depend on the depth of the blood-brain barrier ischemia. The indications of reperfusion in emergency settings are based on pretherapeutic CTscan and angiographic assessment with cerebral digitalized parenchymography. Between 1984 and 1994, 100 ischemic strokes have been treated on emergency by local intra-arterial thrombolysis. The results depend on the condition of lenticulostriate arteries: --when the lenticulostriate arteries are not involved in the occlusion, arterial thrombolysis is very efficient (75% good results; 0% bad results) and has been performed up to the 12th hour. --when the lenticulostriate arteries are involved, the results are not as good (58% good results; 23% bad results); the hemorrhagic risk has dramatically dropped in this group when the decision was taken to do not treat the patients after the 5th hour (16.7% to 2.3%). There has been 7 deaths, 6 were due to non efficient revascularization of the parenchyma with vasogenic oedema. In conclusion, we think that ischemic stroke is an emergency; the cerebral digitalized parenchymography appears to be a major diagnostic and prognostic tool; intra-arterial thrombolysis is a very efficient technique when used at the right site and time.
Acute Disease↗
[Protected carotid angioplasty and carotid stents].
PURPOSE: Endovascular treatment of carotid stenoses. MATERIAL AND METHOD: 259 angioplasties of carotid stenosis are reported. The stenosis was an inflammatory stenosis or a restenosis post endarterectomy in 71 cases, atherosclerotic stenosis in 188 cases. Angioplasty was performed without cerebral protection in 123 cases including a group of 38 with atherosclerotic bifurcation stenosis. A cerebral protection (triple coaxial catheter) was used in 136 atherosclerotic bifurcation stenoses. RESULTS: There has been no complication related to the procedure in the 71 cases of nonatherosclerotic stenosis and the 14 cases of proximal carotid and siphon atherosclerotic stenosis. There has been 5% of dissection and 8% embolic complication in the group of 38 atherosclerotic bifurcation cases treated without cerebral protection. There has been no embolic complication in the 136 atherosclerotic bifurcation cases treated with cerebral protection. There has been 5% dissection in this group before stents and 0% after stents have been used in less then satisfactory results (61 stents placed). Restenosis has also decreased after stents (15% to 4%). CONCLUSION: Endovascular approach can now be considered for all types of carotid stenosis. A cerebral protection with temporary carotid occlusion is mandatory in atherosclerotic carotid bifurcation cases to rule out embolic complication. Complementary stents, when necessary, have reduced the immediate risk of dissection and of restenosis later on.
Adult↗
The multimeric nonstructural NS2 proteins of bluetongue virus, African horsesickness virus, and epizootic hemorrhagic disease virus differ in their single-stranded RNA-binding ability.
The structure and single-stranded (ss) RNA-binding by the nonstructural protein NS2 of three different orbiviruses were studied and compared. African horsesickness virus (AHSV), bluetongue virus (BTV), and epizootic hemorrhagic disease virus (EHDV) were analyzed in recombinant baculovirus-infected cells and in cells infected with BTV and AHSV. Sedimentation analysis and nonreducing SDS-PAGE revealed that NS2 of all three orbiviruses is a 7S multimer with both inter- and intramolecular disulfide bonds, probably consisting of six or more NS2 molecules. The 7S NS2 multimer of all three viruses binds ssRNA but there is a marked disparity in the ssRNA-binding ability between the three proteins. At physiological salt concentration, BTV NS2 binds ssRNA very efficiently, whereas AHSV NS2 shows only a low efficiency for binding ssRNA. EHDV NS2 binds with intermediate efficiency. The result was the same irrespective of whether poly(U)-Sepharose or viral mRNA was used, indicating that ssRNA-binding by NS2 is nonspecific. The difference in RNA-binding ability may be related to the alpha-helix content of the respective proteins. NS2 of BTV has the highest predicted alpha-helix content followed by EHDV and AHSV. The ability of the NS2 proteins to form virus inclusion body-like structures in baculovirus-infected cells is not affected by the ssRNA-binding disparity.
African Horse Sickness Virus↗
[Dural fistula of the cavernous sinus. Treatment through an intravenous approach apropos of 4 cases].
The authors report 4 cases of symptomatic dural fistula of the carotid cavernous sinus treated by transvenous coils. The objectives of dural fistula treatment are now clearly established and several methods are available. Abstention is the rule for asymptomatic forms, whereas symptomatic forms with ophthalmological complications may respond to manual compression of the jugular vein and the carotid artery, arterial embolization, radiotherapy or venous embolization. Arterial embolization results in complete cure in 72% to 78% of the cases, but it is limited by the meningeal supply of the internal carotid artery, with the microcatheter the transvenous route make it possible to treat the meningeal supply from the internal and external carotids without affecting the arterial system, but this technique is restricted by the anatomy of each patient.
Aged↗
Comparison of the expression and phosphorylation of the non-structural protein NS2 of three different orbiviruses: evidence for the involvement of an ubiquitous cellular kinase.
The non-structural protein NS2 of epizootic haemorrhagic disease (EHD), bluetongue (BT) and African horsesickness (AHS) viruses has each been expressed to high levels using a baculovirus vector gene expression system. It was found that the recombinant baculovirus-expressed EHDV NS2 protein was resolved as a doublet following PAGE. Peptide mapping of these protein bands indicated that they were identical. The difference in the sizes of the NS2 protein bands could not be attributed to the phosphorylation of NS2 or other posttranslational modification such as N-glycosylation and remains obscure. The EHDV, BTV and AHSV baculovirus-expressed NS2 proteins were all phosphorylated in vitro without the addition of an exogenous kinase. An unphosphorylated form of EHDV NS2, obtained by expressing the NS2 gene as a fusion protein in Escherichia coli cells, could be phosphorylated in vitro by a protein kinase associated with the cytoplasm of insect cells. The phosphorylated version of this protein was found to be significantly less efficient in binding ssRNA, compared to the unphosphorylated version.
Animals↗
Rotavirus in Saanen goats.
Rotavirus particles were detected in the stools of 8 out of 12 Saanen kids with either diarrhoea or an increased rectal temperature. No other pathogenic organisms could be recovered from these kids. This is believed to be the first report of rotavirus infection in goats in southern Africa.
Africa, Southern↗
Current status of the Strecker stent.
Knitted flexible tantalum stents proved to be a valuable adjunct to percutaneous transluminal angiplasty (PTA) in the case of insufficient PTA results, and their use was established in the distal aorta, the iliac, the femoro-popliteal, the renal, and the coronary arteries. Recently, long arterial occlusions were defined as new indications for primary stenting; stent indications were further extended to the subclavian, the carotid, and the splanchnic arteries. Due to higher incidence of acute and late complications after stent treatment of small diameter arteries, patients have to be selected thoroughly. Newly designed drug-releasing stents tested in animal experiments promised to be suitable to diminish the incidence of late restenosis due to intinal hyperplasia, thus providing better long-term patency.
Angioplasty, Balloon↗