Concentration measurements of bubbles in a water column using an optical tomography system.

Optical tomography provides a means for the determination of the spatial distribution of materials with different optical density in a volume by non-intrusive means. This paper presents results of concentration measurements of gas bubbles in a water column using an optical tomography system. A hydraulic flow rig is used to generate vertical air-water two-phase flows with controllable bubble flow rate. Two approaches are investigated. The first aims to obtain an average gas concentration at the measurement section, the second aims to obtain a gas distribution profile by using tomographic imaging. A hybrid back-projection algorithm is used to calculate concentration profiles from measured sensor values to provide a tomographic image of the measurement cross-section. The algorithm combines the characteristic of an optical sensor as a hard field sensor and the linear back projection algorithm.

Intraarterial thrombolysis for thromboemboli associated with endovascular aneurysm coiling. Report of five cases.

SUMMARY: With the rapidly developing applications of GDC endovascular aneurysm embolization, the recognition and treatment of potential intra-procedural complications is crucial to reducing the morbidity and mortality of this procedure. Thromboembolic complications occur with an incidence of 2-11% with endovascular aneurysm coiling. We describe five cases in which the intraarterial use of thrombolytics was applied to disrupt a fresh clot and recanalize the occluded vessels with variable angiographic and clinical success. Five cases are presented in which thromboembolic complications occurred during or shortly after GDC endovascular aneurysm occlusion. The complication was recognized while depositing coils in two cases, on post-embolization angiogram in one, and a few hours following embolization in two cases in which a new neurologic deficit developed in the ICU. In those cases recognized while the microcatheter was near the aneurysm site, immediate thrombolysis was performed at the site of occlusion. The patients who developed a new neurologic deficit were returned to the endovascular suite and the site of occlusion was noted to be distal to the coiled aneurysm. Clot disruption was performed with the microcatheter before delivering intraarterial thrombolytics. Thromboembolic complications of GDC aneurysm embolization are fortunately rare and can be managed with delivery of thrombolytic therapy at the site of occlusion. Intraarterial thrombolysis of fresh clot caused by GDC aneurysm occlusion can successfully open the occluded vessels but not without serious risk of hemorrhage.

Zebrafish colourless encodes sox10 and specifies non-ectomesenchymal neural crest fates.

Waardenburg-Shah syndrome combines the reduced enteric nervous system characteristic of Hirschsprung's disease with reduced pigment cell number, although the cell biological basis of the disease is unclear. We have analysed a zebrafish Waardenburg-Shah syndrome model. We show that the colourless gene encodes a sox10 homologue, identify sox10 lesions in mutant alleles and rescue the mutant phenotype by ectopic sox10 expression. Using iontophoretic labelling of neural crest cells, we demonstrate that colourless mutant neural crest cells form ectomesenchymal fates. By contrast, neural crest cells which in wild types form non-ectomesenchymal fates generally fail to migrate and do not overtly differentiate. These cells die by apoptosis between 35 and 45 hours post fertilisation. We provide evidence that melanophore defects in colourless mutants can be largely explained by disruption of nacre/mitf expression. We propose that all defects of affected crest derivatives are consistent with a primary role for colourless/sox10 in specification of non-ectomesenchymal crest derivatives. This suggests a novel mechanism for the aetiology of Waardenburg-Shah syndrome in which affected neural crest derivatives fail to be generated from the neural crest.

Rupture of intracranial aneurysms during endovascular coiling: management and outcomes.

OBJECTIVE: In this study, the incidence, etiologies, and management with respect to clinical outcome of patients with iatrogenic aneurysmal rupture during attempted coil embolization of intracranial aneurysms are reviewed. METHODS: A retrospective analysis was conducted of 274 patients with intracranial aneurysms treated with Guglielmi detachable coils over a 6-year period from 1994 to 2000. Patient medical records were examined for demographic data, aneurysm location, the number of coils deployed preceding and after aneurysmal rupture, the etiology of the rupture, and the clinical status on admission and at the time of discharge. RESULTS: Of 274 patients with intracranial aneurysms treated with coil embolization, six (2%) had an intraprocedural rupture. Of these six, two were women and four were men. The mean age was 67 years (range, 52-85 yr). Mean follow-up time was 8 months (range, 0-25 mo). Aneurysmal rupture resulted from detachment of the last coil in three patients, detachment of the third coil (of four) in one patient, and insertion of the first coil in another patient. In one patient, the aneurysmal rupture was a result of catheter advancement before detachment of the last coil. The Glasgow Outcome Scale score at last follow-up examination was 1 in two patients, 2 in two patients, and 5 in two patients. CONCLUSION: The rate of rupture of aneurysms during coil embolization is approximately 2 to 4%. The clinical outcome may be related to the timing of the rupture and the number of coils placed before rupture. If extravasation of contrast agent is seen, which suggests intraprocedural rupture, further coil deposition should be attempted if safely possible.

Transluminal stent-assisted angiplasty of the intracranial vertebrobasilar system for medically refractory, posterior circulation ischemia: early results.

OBJECTIVE: Symptomatic vertebrobasilar artery stenosis portends a poor prognosis, even with medical therapy. Surgical intervention is associated with considerable morbidity, and percutaneous angioplasty alone has demonstrated mixed results, with significant complications. Recent advances in stent technology have allowed for a novel treatment of symptomatic, medically refractory, vertebrobasilar artery stenosis. We report on a series of patients with medically refractory, posterior circulation stenosis who were treated with transluminal angioplasty and stenting at two medical centers in the United States. METHODS: A retrospective analysis of data for 11 consecutive patients with symptomatic, medically refractory, intracranial, vertebral or basilar artery stenosis was performed. All patients were treated with percutaneous transluminal angioplasty and stenting. Short-term clinical and angiographic follow-up data were obtained. RESULTS: Among 11 patients who were treated with stent-assisted angioplasty of the basilar or vertebral arteries, there were three periprocedural deaths and one delayed death after a pontine stroke. Other complications included a second pontine infarction, with subsequent residual diplopia. The remaining seven patients (64%) experienced symptom resolution and have resumed their preprocedural activities of daily living. Angiographic follow-up examinations demonstrated good patency of the stented lesions for five of seven survivors (71%); one patient exhibited minimal intrastent intimal hyperplasia, and another patient developed new stenosis proximal to the stent and also developed an aneurysm within the stented portion of the basilar artery. The last patient exhibited 40% narrowing of the treated portion of the vessel lumen. CONCLUSION: Recent advances in stent technology allow negotiation of the proximal posterior circulation vasculature. Although the treatment of vertebrobasilar artery stenosis with angioplasty and stenting is promising, long-term angiographic and clinical follow-up monitoring of a larger patient population is needed.

Microbiological quality of Australian sheep meat.

Microbiological quality of sheep carcasses and boneless sheep meat produced in Australia was surveyed during the period June to November 1998. Sponge samples were collected from 917 carcasses, and meat samples were drilled from 467 cartons of frozen boneless meat. Carcass and boneless meat samples were respectively collected from 7 and 10 establishments that concentrated on export, and from 36 and 5 establishments supplying the Australian domestic market of which 31 were very small plants slaughtering cattle and sheep but no more than 1,200 sheep equivalents per week. The mean log total viable counts were 3.55/cm2 and 3.30/g for carcasses and boneless meat, respectively. Escherichia coli was detected on 29.2% of carcasses and 24.5% of boneless meat samples and coagulase-positive staphylococci on 24.1% of carcasses, and 38.6% of boneless meat samples. Salmonella was detected on 0.1% of carcasses and 1.3% of boneless meat samples. E. coli O157:H7 was recovered from 0.7% of carcasses and 1.3% of boneless sheep meat. There were statistically significant differences between establishment types for some microbiological criteria, although there were no significant differences in prevalence of Salmonella or E. coli O157:H7 between establishment types. While there were differences in sampling and microbiological techniques between this study and another conducted in 1993 to 1994 that require detailed consideration, there were small but significant improvements in several microbiological criteria for boneless meat. While data that would allow for comparison of carcass data were not gathered, it is unlikely that improvements in the microbiological quality of boneless sheep meat could accrue without improvements to carcasses.

Microbiological quality of Australian beef.

A survey of the microbiological quality of beef carcasses and boneless beef produced in Australia was conducted during the period June to November 1998. Sponge samples were collected from 1,275 carcasses, and meat samples were drilled from 990 cartons of frozen boneless beef. Carcass and boneless beef samples were respectively collected from 21 and 27 establishments that concentrated on export and from 38 and 3 establishments supplying the Australian domestic market of which 31 were very small plants slaughtering no more than 150 cattle equivalents per week. The mean log total viable counts (TVCs) were 2.42/cm2 and 2.52/g for carcasses and boneless meat, respectively. Escherichia coli was detected on 10.3% of carcasses and 5.1% of boneless beef samples and coagulase-positive staphylococci on 24.3% of carcasses and 17.5% of boneless beef. Salmonella was detected on 0.2% of carcasses and 0.1% of boneless beef and E. coli O157:H7 recovered from 0.1% of carcasses but not detected on 990 boneless beef samples. Mean log TVCs/cm2 differed significantly (P < 0.05) between establishment types. They were lower on carcasses from export establishments (2.20) compared with domestic (2.61) and very small plants (3.10). There were no significant differences in prevalence of Salmonella or E. coli O157:H7 between establishment types. Excision samples were taken from 670 carcasses to make comparisons with the first baseline study of Australian meat, carried out in 1993 to 1994. While there were differences in sampling and microbiological techniques between the two studies that require detailed consideration, there were small but significant improvements in several microbiological criteria for carcasses and boneless meat.

Do threatening stimuli draw or hold visual attention in subclinical anxiety?

Biases in information processing undoubtedly play an important role in the maintenance of emotion and emotional disorders. In an attentional cueing paradigm, threat words and angry faces had no advantage over positive or neutral words (or faces) in attracting attention to their own location, even for people who were highly state-anxious. In contrast, the presence of threatening cues (words and faces) had a strong impact on the disengagement of attention. When a threat cue was presented and a target subsequently presented in another location, high state-anxious individuals took longer to detect the target relative to when either a positive or a neutral cue was presented. It is concluded that threat-related stimuli affect attentional dwell time and the disengage component of attention, leaving the question of whether threat stimuli affect the shift component of attention open to debate.

Expression of zebrafish fkd6 in neural crest-derived glia.

The zebrafish fkd6 gene is a marker for premigratory neural crest. In this study, we analyze later expression in putative glia of the peripheral nervous system. Prior to neural crest migration, fkd6 expression is downregulated in crest cells. Subsequently, expression appears initially in loose clusters of cells in positions corresponding to cranial ganglia. Double labelling with a neuronal marker shows that fkd6-expressing cells are not differentiated neurones and generally lie peripheral to neurones in ganglia. Later, expression appears associated with the posterior lateral line and other cranial nerves. For the posterior lateral line nerve, we show that fkd6-labeling extends caudally along this nerve in tight correlation with lateral line primordium migration and axon elongation. Expression in colourless mutant embryos is consistent with these cells being satellite glia and Schwann cells.

Aneurysm retreatment after Guglielmi detachable coil and nondetachable coil embolization: report of nine cases and review of the literature.

OBJECTIVE: Guglielmi detachable coil embolization of cerebral aneurysms is becoming increasingly used to manage certain intracranial lesions based on aneurysm geometry, patient condition, and patient and surgeon preferences. Aneurysm recurrences or incomplete initial treatments are not uncommon, making repeat treatment necessary using either surgical or endovascular techniques. METHODS: Between January 1993 and June 1998, 1025 cerebral aneurysms were managed by the authors at a single hospital. One hundred twenty-four of these lesions were treated using Guglielmi detachable coils, and one was managed with nondetachable coils. During the follow-up period, eight patients who underwent embolization at our institution and one who underwent embolization elsewhere received repeat treatment. Five were approached surgically, and four underwent re-embolization. All charts and films were reviewed retrospectively to determine patient outcome and clinical success. RESULTS: No patient in the subgroup of this clinical study suffered a permanent complication from initial aneurysm coiling, no episodes of subsequent bleeding occurred, and no complications resulted from any subsequent therapies. The anatomic results were excellent, and all aneurysms were totally or near totally obliterated. CONCLUSION: Subtotal initial coil embolization of aneurysms can be managed safely using a variety of surgical and endovascular techniques. Our approach to this predicament, lessons we have learned, and a review of the literature are herein discussed.

Assessment of Complication Types and Rates Related to Diagnostic Angiography and Interventional N euroradiologic Procedures. A Four Year Review (1993-1996).

SUMMARY: We determined the types and rates of complications related to diagnostic angiography and neuroradiologic interventional procedures at a centre that carries out the full spectrum of angiographic procedures. The occurrence of immediate and delayed complications in 1929 neuroangiographic procedures (1358 diagnostic and 571 interventional) performed between the years 1993-1996 was prospectively identified and recorded on a daily basis. A retrospective review of all charts of patients having procedures conducted during the study period was also carried out to ensure that no complications were missed. The overall complication rate for diagnostic cerebral angiography was 2.2%. Puncture site complications ranged from 0 - 0.1 %. Vessel injury distal to the puncture site ranged from 0.2 - 0.6%. The temporary neurologic complication rate was 0.3%, while the permanent rate was 0.4%. There were no contrast reactions. The death rate was 0.1 %. Interventional procedures had higher incidences of complications with overall rates ranging from 5.3 - 33%. Temporary and permanent neurologic deficits occurred at a rate of 0 - 10.5% depending upon the procedure involved. Individual complication and death rates and complication categories are provided for arteriovenous malformation embolisation, tumour embolisation, temporary balloon occlusion tests, detachable balloon vessel sacrifice, urokinase infusion, angioplasty, papavarine infusion, GDC embolisation, and carotid cavernous fistula embolisation. When carried out in experienced hands, neuroangiography and neurointervention are relatively safe with low incidences of neurologic and non-neurologic complications. Knowledge of these rates is important when counselling patients prior to treatments or deciding upon the risk-benefit ratio of preoperative procedures.

The thrill of victory, the complexity of defeat: self-esteem and people's emotional reactions to success and failure.

Low self-esteem people are assumed to have more severe emotional reactions to failure than are high self-esteem people, but this assumption has not received consistent empirical support. In this article the authors report 2 investigations that found that self-esteem differences of this sort emerge for emotions that directly implicate the self (e.g., pride, humiliation) but not for emotions that do not directly implicate the self (e.g., happiness, unhappiness). Additional evidence suggested that this occurs, in part, because low self-esteem people overgeneralize the negative implications of failure. The relevance of these findings for understanding the nature and functions of self-esteem is considered.

CO2 sensitivity changes during the menstrual cycle.

A study of the changes in CO2 sensitivity at rest was undertaken in 20 regularly menstruating females in an attempt to determine the influence of the menstrual cycle on this variable. A biphasic oral temperature graph was used to signify fertility and demarcate three phases of the cycle. A CO2-rebreathing test was conducted 3 times/wk for 6 wk to obtain CO2 sensitivity and CO2 threshold measures. An analysis of variance was used to compare the results collected in each phase of the cycle for each of the variables. A significant increase was found in the sensitivity to CO2 between the follicular and luteal phases, a significant decrease between the luteal and menstrual phases, and no significant difference between the follicular and menstrual phases. The change between follicular and luteal phases was attributed to the effect of progesterone, which is elevated during the luteal phase. No significant change was found in the CO2 threshold level.

Reliability of the Cobb angle index derived by traditional and computer assisted methods.

The reliability of the traditional Cobb angle index, which at present exhibits a wide range of reported values, was determined in this study and amounted to a within subject error of +/-4.3 degrees and a between subject error of +/-4.9 degrees. An attempt to pinpoint the source of this variability by investigating the influence of choice of end vertebrae proved inconclusive. The reliability of a computer assisted Cobb angle index, developed to improve measurement accuracy, was also examined and an estimated within subject error of +/-1.5 degrees and a between subject error of +/-1.6 degrees obtained. A comparison of the traditional and computer assisted methods indicates a high correlation between the Cobb angle derived using the two methods when measuring like curves and an improved reliability obtained by the computer method. Such an improvement is worth implementing clinically but of course the availability of a computer and digitizer and a little extra time for an operator to input the X-ray coordinates may be a barrier to its general use.