Incidence and Clinical Significance of Acute Reocclusion after Emergent Angioplasty or Stenting for Underlying Intracranial Stenosis in Patients with Acute Stroke.

BACKGROUND AND PURPOSE: A major concern after emergent intracranial angioplasty in cases of acute stroke with underlying intracranial stenosis is the acute reocclusion of the treated arteries. This study reports the incidence and clinical outcomes of acute reocclusion of arteries following emergent intracranial angioplasty with or without stent placement for the management of patients with acute stroke with underlying intracranial atherosclerotic stenosis. MATERIALS AND METHODS: Forty-six patients with acute stroke received emergent intracranial angioplasty with or without stent placement for intracranial atherosclerotic stenosis and underwent follow-up head CTA. Acute reocclusion was defined as "hypoattenuation" within an arterial segment with discrete discontinuation of the arterial contrast column, both proximal and distal to the hypoattenuated lesion, on CTA performed before discharge. Angioplasty was defined as "suboptimal" if a residual stenosis of ≥50% was detected on the postprocedural angiography. Clinical and radiologic data of patients with and without reocclusion were compared. RESULTS: Of the 46 patients, 29 and 17 underwent angioplasty with and without stent placement, respectively. Acute reocclusion was observed in 6 patients (13%) and was more frequent among those with suboptimal angioplasty than among those without it (71.4% versus 2.6%, P < .001). The relative risk of acute reocclusion in patients with suboptimal angioplasty was 27.857 (95% confidence interval, 3.806-203.911). Furthermore, a good outcome was significantly less frequent in patients with acute reocclusion than in those without it (16.7% versus 67.5%, P = .028). CONCLUSIONS: Acute reocclusion of treated arteries was common after emergent intracranial angioplasty with or without stent placement in patients with acute stroke with intracranial atherosclerotic stenosis and was associated with a poor outcome. Suboptimal results of angioplasty appear to be associated with acute reocclusion, irrespective of whether stent placement was performed.

Verification of endotracheal tube placement using electrical stimulation through electrodes placed on the endotracheal tube cuff.

BACKGROUND: Current methods for verification of endotracheal intubation can fail, particularly in emergency settings. We investigated whether a verification method using electrical stimulation through electrodes placed on the endotracheal tube cuff could distinguish endotracheal and esophageal intubations in an experimental setting. METHODS: During three sequential sessions simulating emergency intubation without paralysis, rapid sequence intubation (RSI) with neuromuscular blockade, and intubation during cardiopulmonary resuscitation, eight pigs were intubated with an endotracheal tube fitted with two electrodes exposed on the cuff of the tube, first in the esophagus and next in the trachea or in reverse sequence. Cuff pressure was monitored during a 5-s electrical stimulation (20 mA, 80 Hz, 500 µs), and delta pressure was calculated as the difference between baseline cuff pressure and maximum cuff pressure during the electrical stimulation. RESULTS: Delta pressure was significantly higher in esophageal than in tracheal placements in all three sequential sessions (86.0 [78.3-89.7] vs. 6.5 [2.0-7.9] mmHg, P = 0.001; 16.6 [13.2-22.8] vs. 0.8 [0.3-2.6] mmHg, P = 0.004; 66.1 [60.0-84.7] vs. 2.7 [0.7-9.7] mmHg, P = 0.001). The delta pressure did not overlap between tracheal and esophageal intubations except for the session simulating RSI with neuromuscular blockade, in which one of eight esophageal placements showed a delta pressure within the delta pressure range of tracheal placements. CONCLUSION: Electrical stimulation through electrodes placed on the endotracheal tube cuff produced remarkably greater increases in cuff pressure in esophageal intubations than in tracheal intubations in an experimental setting.

Outcomes Are Not Different between Patients with Intermediate and High DWI-ASPECTS after Stent-Retriever Embolectomy for Acute Anterior Circulation Stroke.

BACKGROUND AND PURPOSE: Questions remain as to what benefits embolectomy provides to patients presented with considerable early ischemic changes on baseline imaging studies. This study aimed to investigate the impact of the Alberta Stroke Program Early CT Score applied to DWI on treatment outcomes in patients with acute stroke undergoing stent-retriever embolectomy. MATERIALS AND METHODS: We retrospectively analyzed the clinical and DWI data from 171 patients with acute anterior circulation stroke who were treated with stent-retriever embolectomy within 6 hours of symptom onset. DWI-ASPECTS scores were analyzed with the full scale or were dichotomized (4-6 versus 7-10). Patients with DWI-ASPECTS ≤3 were excluded from the study. Associations between outcome and clinical and radiologic factors were determined with a multivariate logistic regression analysis. A good outcome was defined as a modified Rankin Scale score of 0-2 at 3 months. RESULTS: The median DWI-ASPECTS was 7 (interquartile range, 6-8). The rates of good outcome, symptomatic hemorrhage, and mortality were not different between high DWI-ASPECTS (scores of 7-10) and intermediate DWI-ASPECTS (scores of 4-6) groups. In patients with an intermediate DWI-ASPECTS, good outcome was achieved in 46.5% (20/43) of patients with successful revascularization, whereas no patients without successful revascularization had a good outcome (P = .016). In multivariate logistic regression analysis, independent predictors of good outcome were age and successful revascularization. CONCLUSIONS: Our study suggested that there were no differences in outcomes between patients with a high DWI-ASPECTS and those with an intermediate DWI-ASPECTS who underwent stent-retriever embolectomy for acute anterior circulation stroke. Thus, patients with an intermediate DWI-ASPECTS otherwise eligible for endovascular therapy may not be excluded from stent-retriever embolectomy or stroke trials.

Histologic Analysis of Retrieved Clots in Acute Ischemic Stroke: Correlation with Stroke Etiology and Gradient-Echo MRI.

BACKGROUND AND PURPOSE: It is unclear whether clot composition analysis is helpful to predict a stroke mechanism in acute large vessel occlusion. In addition, the relationship between early vessel signs on imaging studies and clot compositions has been poorly understood. The purpose of this study was to elucidate the relationship between clot composition and stroke etiology following mechanical thrombectomy and to investigate the effect of varied clot compositions on gradient-echo MR imaging of clots. MATERIALS AND METHODS: Histopathologic analysis of retrieved clots from 37 patients with acute MCA occlusion was performed. Patients underwent gradient-echo imaging before endovascular therapy. Retrieved clots underwent semiquantitative proportion analysis to quantify red blood cells, fibrin, platelets, and white blood cells by area. Correlations between clot compositions and stroke subtypes and susceptibility vessel signs on gradient-echo imaging were assessed. RESULTS: Stroke etiology was classified as cardioembolism in 22 patients (59.4%), large-artery atherosclerosis in 8 (21.6%), and undetermined in 7 (18.9%). The clots from cardioembolism had a significantly higher proportion of red blood cells (37.8% versus 16.9%, P = .031) and a lower proportion of fibrin (32.3% versus 48.5%, P = .044) compared with those from large-artery atherosclerosis. The proportion of red blood cells was significantly higher in clots with a susceptibility vessel sign than in those without it (48.0% versus 1.9%, P < .001), whereas the proportions of fibrin (26.4% versus 57.0%, P < .001) and platelets (22.6% versus 36.9%, P = .011) were significantly higher in clots without a susceptibility vessel sign than those with it. CONCLUSIONS: The histologic composition of clots retrieved from cerebral arteries in patients with acute stroke differs between those with cardioembolism and large-artery atherosclerosis. In addition, a susceptibility vessel sign on gradient-echo imaging is strongly associated with a high proportion of red blood cells and a low proportion of fibrin and platelets in retrieved clots.

Negative Susceptibility Vessel Sign and Underlying Intracranial Atherosclerotic Stenosis in Acute Middle Cerebral Artery Occlusion.

BACKGROUND AND PURPOSE: The role of MR imaging in predicting underlying intracranial atherosclerotic stenosis before endovascular stroke therapy has not been studied. Our aim was to determine the diagnostic value of the negative susceptibility vessel sign on T2*-weighted gradient-echo MR imaging for predicting underlying intracranial atherosclerotic stenosis in patients with acute MCA occlusion. MATERIALS AND METHODS: Ninety-one consecutive patients with acute stroke because of MCA occlusion underwent gradient-echo MR imaging and MRA before endovascular therapy. The negative susceptibility vessel sign was defined as an absence of a hypointense signal change within the occluded MCA on gradient-echo imaging. Underlying intracranial atherosclerotic stenosis was determined by conventional angiography. The sensitivity, specificity, predictive values, and accuracy of the negative susceptibility vessel sign for predicting the presence of underlying intracranial atherosclerotic stenosis were assessed. RESULTS: The negative susceptibility vessel sign was identified in 42 (46.1%) of 91 patients, and 18 (19.8%) patients had an underlying intracranial atherosclerotic stenosis responsible for acute ischemic symptoms. The negative susceptibility vessel sign was more frequently observed in patients with intracranial atherosclerotic stenosis than in those without it (100% versus 32.9%, P < .001). In the prediction of an underlying intracranial atherosclerotic stenosis, the negative susceptibility vessel sign had 100% sensitivity, 67.1% specificity, 42.9% positive predictive value, 100% negative predictive value, and an accuracy of 73.6%. CONCLUSIONS: The negative susceptibility vessel sign on gradient-echo MR imaging is a sensitive marker with a high negative predictive value for the presence of an underlying intracranial atherosclerotic stenosis in patients with acute ischemic stroke because of MCA occlusions. The susceptibility vessel sign can be used in decision-making when performing subsequent endovascular revascularization therapy in patients with acute MCA occlusions.

Sustained manual abdominal compression during cardiopulmonary resuscitation in a pig model: a preliminary investigation.

OBJECTIVES: The present study was undertaken to determine whether sustained manual abdominal compression (SMAC) using left paramedian compression technique can improve coronary perfusion pressure (CPP) during cardiopulmonary resuscitation (CPR) and resuscitation outcomes without causing liver laceration. METHODS: Ventricular fibrillation was induced in 14 pigs, and circulatory arrest was maintained for 6 min. Animals were resuscitated either by standard CPR (control group) or by standard CPR with SMAC (SMAC-CPR group). RESULTS: Mean blood pressure, aortic diastolic pressure and right atrial diastolic pressure in the SMAC-CPR group were significantly greater than in the control group throughout simulated basic life support. However, since the increases in aortic and right atrial diastolic pressures were similar, no significant intergroup difference was found in terms of CPP. Return of spontaneous circulation (ROSC) was attained in four of seven animals in the control group and in six of seven animals in the SMAC-CPR group (p = 0.55). Three animals in the control group and four in the SMAC-CPR group survived 24 h after ROSC (p = 1.00). Two of the seven animals in the SMAC-CPR group had a ruptured liver, but no such injury occurred in the control group. CONCLUSIONS: SMAC using left paramedian compression technique failed to improve CPP during CPR and resuscitation outcomes. Furthermore, this method could not avoid liver laceration.

A potential role of the heparan sulfate in the hepatitis C virus attachment.

Several putative cell surface receptors have been identified in the Hepatitis C virus (HCV) infection including CD81, low-density lipoprotein (LDL) receptor, scavenger receptor class B type I (SR-BI), and highly sulfated heparan sulfate (HS). In this study, we showed that the binding of soluble heparin to the envelope glycoprotein E2 (E2) of HCV was dependent on the dose and conformation of E2. On the other hand, the binding of E2 to the cell surface after treatment with soluble heparin was not markedly inhibited, what was different from other viruses utilizing cellular HS as the primary receptor. However, the enzymatic removal of HS from the cell surface led to a significant reduction in the binding of E2 to the cells. These facts imply that E2 was bound to cellular HS but might also have another route for cell attachment. Monoclonal antibodies with neutralizing activity against E2 did not completely block the binding of E2 to the cell surface, but their neutralization activity was greatly enhanced in the presence of soluble heparin. Taken together, the cellular HS could act as an alternative receptor for HCV and the interaction of E2 with HS could play a distinct role in escaping of HCV from the humoral immunity.

Alleviation of osteoarthritis by calycosin-7-O-beta-D-glucopyranoside (CG) isolated from Astragali radix (AR) in rabbit osteoarthritis (OA) model.

OBJECTIVE: This work was undertaken to assess the protective effect of an isoflavonoid, calycosin-7-O-beta-D-glucopyranoside (CG), isolated from Astragali radix (AR) on the pathogenesis of osteoarthritis (OA)-like lesion in a rabbit model. METHODS: Nine rabbits underwent an anterior cruciate ligament and menisectomy transection (ACLMT) of the rear knee joints to induce OA-like lesion. They were randomly divided into three groups (n=6/group): a negative control group treated with 200 microl of 0.5% (v/v) dimethyl sulfoxide (DMSO), a positive control group treated with 200 microl of 100 microM piroxicam, and a test group treated with 100 microg/500 microl of CG, where the test agents were administered by injection once a week for 4 weeks starting from the third week. Rabbits were then sacrificed to observe the progression of OA-like lesion. The synovial fluid was analyzed for the amounts of total proteins, glycosaminoglycans (GAG) and prostaglandin E(2) (PGE(2)). In addition, histopathologic analyses were performed on the OA-like articular cartilage with or without therapeutic treatments. RESULTS: The total synovial fluid volume (P<0.05) was most strikingly reduced by the treatment with CG. Moreover, the CG treatment also significantly alleviated the OA-induced accumulation of prostaglandin (PG) (P<0.001) and total proteins (P<0.001) in the synovial fluid. The histopathologic analyses revealed that the CG treatment reduced the severity of the OA-like structural damages in the cartilage. However, the level of PGE(2), a pathologic inflammatory molecule, was not diminished by CG or piroxicam. CONCLUSION: These results indicate that the isoflavonoid CG isolated from AR significantly alleviated the pathologic changes in the OA-like rabbit knee joints. This suggests that CG from AR could be a promising treatment for the therapy of OA.

Thin layer chromatographic determination of organic acids for rapid identification of bifidobacteria at genus level.

This study presents a simple and fast method for the identification of bifidobacteria using a thin layer chromatographic (TLC) analysis of the short chain fatty acids in a culture broth. When the chromatogram was sprayed with the indicator solution (methyl red-bromophenol blue in 70% ethanol), lactic acid exhibited two red spots, and acetic acid, propionic acid, and butyric acid all produced blue spots. Succinic acid and citric acid produced yellow and dark yellow spot, respectively. In addition, these organic acids showed different R(f) values. The total time taken to analyze the organic acids in the 10 bacterial culture broths using the proposed method was approximately 50 min. The proposed TLC method was used to analyze the organic acids in culture broths of the following strains, five Bifidobacterium species. (Bifidobacterium longum, B. breve, B. infantis, B. bifidum, and B. adolescentis) and five other lactic acid bacteria strains (Lactobacillus casei, L. bulgaricus, L. acidophilus, Streptococcus thermophilus, and S. lactis). Both spots of lactic acid and acetic acid were detected on all the TLC plates from the five bifidobacterial culture broths. The five other lactic acid bacterial culture broths, however, only exhibited lactic acid spots. Accordingly, the proposed TLC method would appear to be a useful tool for rapid identification of Bifidobacterium spp. at the genus level.

Pretreatment of whole blood for use in immunochromatographic assays for hepatitis B virus surface antigen.

Immunochromatographic assays (ICAs) are also referred to as rapid tests, since they are simple and the results can be obtained within minutes after manually loading a few drops of a sample into each sample well of the test device. However, whole blood cannot be tested with ICA kits due to the visual hindrance caused by the color of red blood cells (RBCs), unless a cell-removing device such as a filter is mounted on the kits. Thus, when testing with blood, the advantage of the ICA kit is lost because of the additional time and machines required to coagulate and separate whole blood before preparing the serum. To overcome this limitation, whole-blood samples were added to a pretreatment solution to decolor the RBCs; the resulting mixtures were then loaded into the sample wells of the test device. The pretreating solution was composed of hydrogen peroxide (H(2)O(2)) to decolor the RBCs, Sag 471 (Osi Specialties) to restrain the mixture from vigorous foaming, sodium azide (NaN(3)) to inhibit the enzyme, which generates excessive foam at the beginning of decolorization, and EDTA as a chelating agent. As a result of this pretreatment, whole blood could be used with the ICA kit without reducing its simplicity and rapidity.

Survival of Bifidobacterium longum immobilized in calcium alginate beads in simulated gastric juices and bile salt solution.

Bifidobacterium longum KCTC 3128 and HLC 3742 were independently immobilized (entrapped) in calcium alginate beads containing 2, 3, and 4% sodium alginate. When the bifidobacteria entrapped in calcium alginate beads were exposed to simulated gastric juices and a bile salt solution, the death rate of the cells in the beads decreased proportionally with an increase in both the alginate gel concentration and bead size. The initial cell numbers in the beads affected the numbers of survivors after exposure to these solutions; however, the death rates of the viable cells were not affected. Accordingly, a mathematical model was formulated which expressed the influences of several parameters (gel concentration, bead size, and initial cell numbers) on the survival of entrapped bifidobacteria after sequential exposure to simulated gastric juices followed by a bile salt solution. The model proposed in this paper may be useful for estimating the survival of bifidobacteria in beads and establishing optimal entrapment conditions.