Flow quantification of the non-occlusive excimer laser-assisted EC-IC bypass

Summary  Background. For six years, we used the Excimer laser-assisted nonocclusive anastomosis technique for high-flow revascularization of the brain in patients with either nonclippable and noncoilable giant aneurysms of the internal carotid or basilar artery or progressive stroke associated with occlusive disease of the internal carotid artery. The aim of this study is to assess the blood flow capacity of this type of Extra-Intracranial bypass and its haemodynamic behaviour over time.  Methods. Twenty-six patients with a giant aneurysms and 8 patients with occlusive disease of the internal carotid artery were treated with the nonocclusive Excimer laser assisted EC-IC bypass. intra-operatively, direct measurements of flow in the EC-IC bypass were performed in all patients (Transonic Systems, Inc., Ithaca, NY). Postoperatively, follow up measurements of flow were performed with MR angiography in 14 patients with a giant aneurysm after occluding the internal carotid artery, and 7 patients with occlusive carotid disease.  Results. The mean flow in the laser assisted bypasses in the group of patients with a giant aneurysm was 158 ml/min after ligation or balloon oclusion of the ICA. The mean flow of the laser assisted bypass in the group of patients with ICA occlusive disease was 130 ml/min. A comparison with data on flow capacity of conventional EC IC bypasses is made. A demonstrated increase of flow in the bypass during follow up is discussed from a haemodynamic point of view.  Conclusions. The results of this study demonstrate that the flow capacity of the nonoccluding excimer laser assisted bypass is much higher than the capacity of the conventional, more peripherally located conventional EC IC bypass, and should therefore be denoted as High-Flow EC IC bypass. Consequently, this type of bypass can be a powerful and safe tool in new revascularization strategies.     

Excimer laser-assisted bypass in aneurysm treatment: short-term outcomes

OBJECT: If clip application or coil placement for treatment of intracranial aneurysms is not feasible, the parent vessel can be occluded to induce thrombosis of the aneurysm. The Excimer laser-assisted anastomosis technique allows the construction of a high-flow bypass in patients who cannot tolerate such an occlusion. The authors assessed the complications of this procedure and clinical outcomes after the construction of high-flow bypasses in patients with intracranial aneurysms. METHODS: Data were retrospectively collected on patient and aneurysm characteristics, procedural complications, and functional outcomes in 77 patients in whom a high-flow bypass was constructed. Logistic regression analysis was used to quantify the relationships between patient and aneurysm characteristics on the one hand and outcome measures on the other. Fifty-one patients harbored a giant aneurysm, 24 patients suffered from a ruptured aneurysm, and 35 patients from an unruptured symptomatic aneurysm. In 22 patients (29%; 95% confidence interval [CI] 19-40%) a permanent deficit developed from an operative complication. At a median follow-up period of 2.5 months, 25 patients (32%; 95% CI 22-44%) were dependent or had died; in 10 of these patients (13% of all patients; 95% CI 6-23%) operative complications were the single cause of this poor outcome. Univariate analysis demonstrated that a poor clinical condition before treatment (odds ratio [OR] 4.7; 95% CI 1.7-13.3) and a history of cardiovascular disease (OR 4.1; 95% CI 1-16.2) increased the risk of poor outcome. Multivariate analysis demonstrated that only the clinical condition before treatment was significantly related to outcome (OR 4; 95% CI 1.3-11.9). CONCLUSIONS: In patients with an intracranial aneurysm that cannot be treated by clip application or coil placement, and in whom occlusion of the parent artery cannot be tolerated, the construction of a high-flow bypass should be considered. This procedure carries a considerable risk of complications, but this should be weighed against the disabling or life-threatening effects of compression, the high risk of rupture, and the substantial chance of poor outcome after the rupture of such aneurysms.     

Punishment of food rewarded lever holding in male and female rats

Up to now, better retention of passive avoidance behavior by male rats has been observed only in situations involving the re-entry into a compartment as the punished response. The present study is aimed at investigating whether this sex difference can be generalized to situations in which this spatial factor is unimportant. Male and female rats were trained to hold down a lever continuously for ten seconds to obtain a food pellet. After extensive training on this program, two sessions were scheduled in which both a food pellet and a foot shock were contingent to lever holding. Extinction of punishment was studied in twenty-four sessions in which animals again only received a food pellet upon meeting the requirement for reinforcement. Although the effects of punishment extinguished very slowly, females showed faster extinction than males. They emitted more responses and received more reinforcers during the postshock stage. In addition, male rats showed more abortive responding, i.e., in males a higher percentage of responses was terminated before meeting the requirement for reinforcement. Several hypotheses accounting for sex differences in aversively motivated learning are discussed. The present data are taken as support for the fear motivation hypothesis.     

Comparison of DRB sequence-based typing using different strategies

Sequence-based typing (SBT) has become an important tool in the identification of HLA alleles. In this study a comparison was made between SBT of DRB 1/3/4/5 alleles performed in two laboratories each using a different strategy for SBT. The laboratories in Utrecht and in Maastricht performed direct sequencing of PCR amplified genomic DNA from 30 selected samples. Primers and conditions for PCR amplification were different. Sequencing was either performed with T7 polymerase, using internal sequencing primers, or with cycle sequencing using an M13 tailed system. Two different automated DNA sequencers were used; the ALFexpress from Pharmacia and Applied Biosystems 373 A. We concluded that nor the method of sequencing nor the sequencing machine influences typing results. However the PCR reaction used for generating template DNA is the most critical step. Different primers and different conditions can lead to false negative reactions. The fact that these false negative reactions can occur with different alleles in different combinations but not in all, implicates that extensive quality control is needed to assure correct typing results.     

Global form perception: interactions between luminance and texture information.

PURPOSE: This experiment reports the independence of first- and second-order processing mechanisms in form perception. METHODS: Symmetrical dot patterns were created using either luminance-increment dots (luminance above background), or texture-defined dots (average luminance equal to background). The proportion of luminance increment or texture dots defining each pattern was varied among fields of noise dots of the same type to determine symmetry detection thresholds. RESULTS: Differences in detection thresholds were found between luminance- and texture-defined patterns. Further, symmetry detection thresholds for luminance-increment dot patterns were resistant to noise defined by dots of opposite contrast polarity (luminance-decrement dots) or texture, while texture-defined patterns were resistant to neither texture nor luminance-decrement noise. CONCLUSIONS: These data suggest that symmetry perception, along with other types of form perception, use both first- and second-order processing mechanisms. The data are compatible with a second-order system that includes a negative half-wave rectifying non-linearity.     

Description of a new DRB1*11 allele (DRB1*1132)

Abstract: We describe a new DRB1*11 allele which is similar to DRB1*11011 except at codon 74, where a GCG is changed for a GTG leading to an alanine/valine substitution. This new allele was carried by a Caucasian patient suffering from rheumatoid arthritis and by her healthy daughter. The motif at codon 74 of the new DRB1*11 is not found in any other known DRB alleles, nor among the published DQA1, DQB1, DPA1 or DPB1 alleles, and therefore suggests a mechanism of point mutation.     

DPB1*7601, a novel DPB1 variant in the Caucasoid population

Abstract: A new DPB1 allele has been identified in a Caucasoid individual, DPB1*7601. The sequence of the complete second exon has been confirmed by cloning and subsequent sequencing. This allele differs by one amino acid, at codon 36, from DPB1*1401, as indicated by SBT and PCR-SSP analysis. The amino-acid motif introduced by the change is shared by DPB1*0401 and some rare alleles. It remains unclear whether the change is due to interallelic microgen conversion or a single point mutation.     

Safety and biodegradability of a synthetic dural sealant patch (Liqoseal) in a porcine cranial model

BackgroundLiqoseal consists of a watertight layer of poly(ester)ether urethane and an adhesive layer containing polyethylene glycol‐N‐hydroxysuccinimide (PEG‐NHS). It is designed to prevent cerebrospinal fluid (CSF) leakage after intradural surgery. This study assessed the safety and biodegradability of Liqoseal in a porcine craniotomy model.MethodsIn 32 pigs a craniotomy plus durotomy was performed. In 15 pigs Liqoseal was implanted, in 11 control pigs no sealant was implanted and in 6 control pigs a control dural sealant (Duraseal or Tachosil) was implanted. The safety of Liqoseal was evaluated by clinical, MRI and histological assessment. The degradation of Liqoseal was histologically estimated.ResultsLiqoseal, 2 mm thick before application, did not swell and significantly was at maximum mean thickness of 2.14 (±0.37) mm at one month. The foreign body reaction induced by Liqoseal, Duraseal and Tachosil were comparable. Liqoseal showed no adherence to the arachnoid layer and was completely resorbed between 6 and 12 months postoperatively. In one animal with Liqoseal, an epidural fluid collection containing CSF could not be excluded.ConclusionLiqoseal seems to be safe for intracranial use and is biodegradable. The safety and performance in humans needs to be further assessed in clinical trials.