On the nature of “Maculotoxin”, a toxin from the blue-ringed octopus (Hapalochlaena maculosa)

Two lethal fractions were prepared from the posterior salivary glands of Hapalochlaena maculosa by methanol extraction and chromatography on a silica gel column. These two fractions were compared with the lethal water extract of the glands, previously named maculotoxin (MTX), by thin layer and ion exclusion chromatography. It was concluded that the two methanol fractions contained the same active principle, that this was the same material as MTX, and that it closely resembled tetrodotoxin. No evidence for the existence of a second toxin in effective amounts was found.     

Use of quantitative EEG in infants with port-wine birthmark to assess for Sturge–Weber brain involvement

ObjectiveMany infants born with a facial port-wine (PW) birthmark will not develop brain involvement of Sturge–Weber syndrome (SWS). Previous studies have shown asymmetry in quantitative EEG (qEEG) correlates with degree of clinical impairment in children and adults with known SWS. We hope to determine if quantitative qEEG can be used as a method to predict which infants are most likely to develop SWS brain involvement on MRI. The current study looks at the ability of qEEG to differentiate between infants with radiographically demonstrated SWS and those without.MethodsWe first performed an observational study of qEEG results on eight infants with facial PW birthmark (four had SWS brain involvement). We recorded standard clinical EEGs and then derived a measure of asymmetry. We subsequently validated this threshold through a study of an additional nine infants with PW birthmark (five with SWS brain involvement).ResultsQuantitative EEG correctly identified infants with SWS brain involvement in all cases in the Validation cohort. This technique was at least as good as a pediatric electroencephalographer with extensive experience reading SWS EEGs.ConclusionsThis study demonstrates the ability for qEEG to discriminate between those infants with SWS brain involvement and those with neurologically asymptomatic PW birthmark.SignificanceThis study represents an important step toward the development of a qEEG technique able to predict which infants with PW birthmark will develop SWS brain involvement.     

Glykogenose 1non-a

Hintergrund. Die Glykogenose 1non-a ist durch einen Defekt des mikrosomalen Glukose-6-Phosphat-Transporters bedingt.     

Health impact assessment and short-term medical missions: A methods study to evaluate quality of care

Background  

Short-term medical missions (STMMs) are a well-established means of providing health care to the developing world. Despite over 250 million dollars and thousands of volunteer hours dedicated to STMMs, there is a lack of standardized evaluation to assess patient safety, quality control, and mission impact. The objective of this project is to design and implement an assessment tool that defines objective parameters of quality of care as identified by STMMs.     

Electrocorticographic gamma activity during word production in spoken and sign language.

OBJECTIVE: To investigate the functional-neuroanatomic substrates of word production using signed versus spoken language. METHODS: The authors studied single-word processing with varying input and output modalities in a 38-year-old woman with normal hearing and speech who had become proficient in sign language 8 years before developing intractable epilepsy. Subdural electrocorticography (ECoG) was performed during picture naming and word reading (visual inputs) and word repetition (auditory inputs); these tasks were repeated with speech and with sign language responses. Cortical activation was indexed by event-related power augmentation in the 80- to 100-Hz gamma band, and was compared with general principles of functional anatomy and with subject-specific maps of the same or similar tasks using electrical cortical stimulation (ECS). RESULTS: Speech outputs activated tongue regions of the sensorimotor cortex, and sign outputs activated hand regions. In addition, signed word production activated parietal regions that were not activated by spoken word production. Posterior superior temporal gyrus was activated earliest and to the greatest extent during auditory word repetition, and the basal temporal-occipital cortex was activated similarly during naming and reading, reflecting the different modalities of input processing. With few exceptions, topographic patterns of ECoG gamma were consistent with ECS maps of the same or similar language tasks. CONCLUSIONS: Spoken and signed word production activated many of the same cortical regions, particularly those processing auditory and visual inputs; however, they activated different regions of sensorimotor cortex, and signing activated parietal cortex more than did speech. This study illustrates the utility of electrocorticographic gamma for studying the neuroanatomy and processing dynamics of human language.     

Cardiac concomitants of performance monitoring: context dependence and individual differences

Feedback processing is an important aspect of cognitive control and decision-making. Several studies have shown that heart rate slows following feedback that indicates incorrect performance or loss of money. The current study was the first to investigate (1) whether this slowing reflects an evaluation of the valence of the outcome or a system that indicates that the feedback contains informative value, (2) whether the slowing is determined by the value of the outcome relative to the range of possible outcomes, and (3) whether highly anxious individuals have a hypersensitive feedback monitoring system. The results showed that heart rate only slows when the feedback is performance based. The information provided by negative feedback is processed in a context-sensitive manner, suggesting that heart rate slowing following feedback reflects a signal associated with informative value for subsequent performance adjustment. Highly anxious individuals showed larger heart rate slowing in response to feedback indicating high stakes, but they failed to respond to feedback in a context-sensitive manner. These results were interpreted to suggest that anxious individuals are generally more sensitive to performance outcomes. Heart rate changes following informative feedback proved to be a sensitive index of component processes associated with performance monitoring.     

Computationally efficient approaches to calculating significant ERD/ERS changes in the time-frequency plane

This paper addresses some practical issues related to the calculation, display and assessment of the significance of changes in the average time-frequency energy density of event-related brain activity. Using scalp EEG and subdural ECoG example datasets, parametric tests are evaluated as a replacement for previously applied computer-intensive resampling methods. The performance of different estimates of energy density, based on matching pursuit, scalogram and spectrogram, and their Box-Cox transformations is evaluated with respect to the assumption of normality required for the t-test, and the consistency of the final results.     

Identification of a unique gene expression signature that differentiates hepatocellular adenoma from well-differentiated hepatocellular carcinoma

It is often difficult to distinguish hepatocellular adenoma (HCA) from well-differentiated hepatocellular carcinoma (WDHCC) when limited tissue from a needle biopsy is evaluated. The aim of this study was to identify gene expression patterns that can distinguish HCA from WDHCC, with the ultimate goal of discovering novel diagnostic markers. Gene expression profile analysis was performed using Affymetrix U133Plus2 GeneChip microarrays on RNA isolated from frozen tissue of 6 HCA and 8 WDHCC specimens. Statistical analysis of microarray data identified 63 genes whose expression levels were significantly different between HCA and WDHCC. These included 57 genes overexpressed by HCA and 6 overexpressed by WDHCC. Eight genes were chosen for further analysis by quantitative RT-PCR on RNA derived from archived, paraffin-embedded tissue blocks of an independent validation set comprising 9 HCAs and 9 HCCs. Seven of the 8 genes demonstrated average expression differences between HCA and HCC that were concordant with the microarray findings, and their expression pattern correctly classified the 18 tumors into HCA and HCC using unsupervised clustering analysis. Furthermore, immunohistochemical staining performed on a third, independent set of 27 HCAs and 33 HCCs confirmed the expression differences at protein levels for 5 of the genes. Taken together, our data demonstrate significant molecular differences between HCA and WDHCC, despite their morphologic similarity. More importantly, we have identified a unique set of genes whose expression pattern can discriminate between these two types of hepatocellular neoplasms, suggesting the possibility of future development of ancillary molecular and immunohistochemical diagnostic methods.     

Recurrence of cerebral arteriovenous malformations in children: report of two cases and review of the literature

BACKGROUND: Angiography is considered the standard to assess the treatment success of cerebral arteriovenous malformations (AVMs). When postoperative angiograms show neither residual nidus nor early draining veins, patients are considered cured, and the risks of hemorrhage are eliminated. However, this notion is challenged by the development of recurrent AVMs in children. In our report, 2 children developed recurrent AVMs after undergoing complete resection, which was documented by postoperative angiography. We review other similar cases reported in the literature to help establish guidelines for postoperative monitoring. METHODS: In this retrospective review, 36 children underwent complete surgical resection of cerebral AVMs that were documented by intra- or postoperative angiography. After a follow-up period ranging from 1 to 17 years, rates of recurrence were assessed. RESULTS: Although angiographic documentation showed complete resection, 2 children developed recurrences 3 and 5 years later. Among these 36 children, the recurrence rate was 5.5% at follow-up (mean 9 years). CONCLUSIONS: Based on our data and review of the literature, intra- or early postoperative angiography is essential to exclude the presence of a residual nidus but does not ensure cure of the AVMs in children. If postoperative angiographic scans are obtained too early, postoperative changes may prevent the detection of a residual nidus. Therefore, we recommend that angiographic scans be obtained intraoperatively or early postoperatively to document complete resection and again at 1 and 5 years after surgical resection.