Longitudinal Stability of Intellectual Functioning in Autism Spectrum Disorder: From Age 3 Through Mid-adulthood

Intelligence (IQ) scores are used in educational and vocational planning for individuals with autism spectrum disorder (ASD) yet little is known about the stability of IQ throughout development. We examined longitudinal age-related IQ stability in 119 individuals with ASD (3-36 years of age at first visit) and 128 typically developing controls. Intelligence measures were collected over a 20-year period. In ASD, Full Scale (FSIQ) and Verbal (VIQ) Intelligence started lower in childhood and increased at a greater rate with age relative to the control group. By early adulthood, VIQ and working memory stabilized, whereas nonverbal and perceptual scores continued to change. Our results suggest that in individuals with ASD, IQ estimates may be dynamic in childhood and young adulthood.

Increased Functional Connectivity After Listening to Favored Music in Adults With Alzheimer Dementia

BACKGROUND

Personalized music programs have been proposed as an adjunct therapy for patients with Alzheimer disease related dementia, and multicenter trials have now demonstrated improvements in agitation, anxiety, and behavioral symptoms. Underlying neurophysiological mechanisms for these effects remain unclear.

METHODS

We examined 17 individuals with a clinical diagnosis of Alzheimer disease related dementia using functional MRI following a training period in a personalized music listening program.

RESULTS

We find that participants listening to preferred music show specific activation of the supplementary motor area, a region that has been associated with memory for familiar music that is typically spared in early Alzheimer disease. We also find widespread increases in functional connectivity in corticocortical and corticocerebellar networks following presentation of preferred musical stimuli, suggesting a transient effect on brain function.

CONCLUSIONS

Findings support a mechanism whereby attentional network activation in the brain's salience network may lead to improvements in brain network synchronization.

Functional MRI connectivity of children with autism and low verbal and cognitive performance

Background

Functional neuroimaging research in autism spectrum disorder has reported patterns of decreased long-range, within-network, and interhemispheric connectivity. Research has also reported increased corticostriatal connectivity and between-network connectivity for default and attentional networks. Past studies have excluded individuals with autism and low verbal and cognitive performance (LVCP), so connectivity in individuals more significantly affected with autism has not yet been studied. This represents a critical gap in our understanding of brain function across the autism spectrum.

Methods

Using behavioral support procedures adapted from Nordahl, et al. (J Neurodev Disord 8:20–20, 2016), we completed non-sedated structural and functional MRI scans of 56 children ages 7–17, including LVCP children (n = 17, mean IQ = 54), children with autism and higher performance (HVCP, n = 20, mean IQ = 106), and neurotypical children (NT, n = 19, mean IQ = 111). Preparation included detailed intake questionnaires, video modeling, behavioral and anxiety reduction techniques, active noise-canceling headphones, and in-scan presentation of the Inscapes movie paradigm from Vanderwal et al. (Neuroimage 122:222–32, 2015). A high temporal resolution multiband echoplanar fMRI protocol analyzed motion-free time series data, extracted from concatenated volumes to mitigate the influence of motion artifact. All participants had > 200 volumes of motion-free fMRI scanning. Analyses were corrected for multiple comparisons.

Results

LVCP showed decreased within-network connectivity in default, salience, auditory, and frontoparietal networks (LVCP < HVCP) and decreased interhemispheric connectivity (LVCP < HVCP=NT). Between-network connectivity was higher for LVCP than NT between default and dorsal attention and frontoparietal networks. Lower IQ was associated with decreased connectivity within the default network and increased connectivity between default and dorsal attention networks.

Conclusions

This study demonstrates that with moderate levels of support, including readily available techniques, information about brain similarities and differences in LVCP individuals can be further studied. This initial study suggested decreased network segmentation and integration in LVCP individuals. Further imaging studies of LVCP individuals with larger samples will add to understanding of origins and effects of autism on brain function and behavior.

Electronic supplementary material

The online version of this article (10.1186/s13229-018-0248-y) contains supplementary material, which is available to authorized users.

Longitudinal development of thalamic and internal capsule microstructure in autism spectrum disorder

The thalamus is a key sensorimotor relay area that is implicated in autism spectrum disorder (ASD). However, it is unknown how the thalamus and white-matter structures that contain thalamo-cortical fiber connections (e.g., the internal capsule) develop from childhood into adulthood and whether this microstructure relates to basic motor challenges in ASD. We used diffusion weighted imaging in a cohort-sequential design to assess longitudinal development of the thalamus, and posterior- and anterior-limbs of the internal capsule (PLIC and ALIC, respectively) in 89 males with ASD and 56 males with typical development (3-41 years; all verbal). Our results showed that the group with ASD exhibited different developmental trajectories of microstructure in all regions, demonstrating childhood group differences that appeared to approach and, in some cases, surpass the typically developing group in adolescence and adulthood. The PLIC (but not ALIC nor thalamus) mediated the relation between age and finger-tapping speed in both groups. Yet, the gap in finger-tapping speed appeared to widen at the same time that the between-group gap in the PLIC appeared to narrow. Overall, these results suggest that childhood group differences in microstructure of the thalamus and PLIC become less robust in adolescence and adulthood. Further, finger-tapping speed appears to be mediated by the PLIC in both groups, but group differences in motor speed that widen during adolescence and adulthood suggest that factors beyond the microstructure of the thalamus and internal capsule may contribute to atypical motor profiles in ASD. Autism Res 2018, 11: 450-462. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

LAY SUMMARY

Microstructure of the thalamus, a key sensory and motor brain area, appears to develop differently in individuals with autism spectrum disorder (ASD). Microstructure is important because it informs us of the density and organization of different brain tissues. During childhood, thalamic microstructure was distinct in the ASD group compared to the typically developing group. However, these group differences appeared to narrow with age, suggesting that the thalamus continues to dynamically change in ASD into adulthood.

High-throughput synthesis and characterization of nanocrystalline porphyrinic zirconium metal-organic frameworks

We describe and employ a high-throughput screening method to accelerate the synthesis and identification of pure-phase, nanocrystalline metal-organic frameworks (MOFs). We demonstrate the efficacy of this method through its application to a series of porphyrinic zirconium MOFs, resulting in the isolation of MOF-525, MOF-545, and PCN-223 on the nanoscale.

Multivariate characterization of white matter heterogeneity in autism spectrum disorder

The complexity and heterogeneity of neuroimaging findings in individuals with autism spectrum disorder has suggested that many of the underlying alterations are subtle and involve many brain regions and networks. The ability to account for multivariate brain features and identify neuroimaging measures that can be used to characterize individual variation have thus become increasingly important for interpreting and understanding the neurobiological mechanisms of autism. In the present study, we utilize the Mahalanobis distance, a multidimensional counterpart of the Euclidean distance, as an informative index to characterize individual brain variation and deviation in autism. Longitudinal diffusion tensor imaging data from 149 participants (92 diagnosed with autism spectrum disorder and 57 typically developing controls) between 3.1 and 36.83 years of age were acquired over a roughly 10-year period and used to construct the Mahalanobis distance from regional measures of white matter microstructure. Mahalanobis distances were significantly greater and more variable in the autistic individuals as compared to control participants, demonstrating increased atypicalities and variation in the group of individuals diagnosed with autism spectrum disorder. Distributions of multivariate measures were also found to provide greater discrimination and more sensitive delineation between autistic and typically developing individuals than conventional univariate measures, while also being significantly associated with observed traits of the autism group. These results help substantiate autism as a truly heterogeneous neurodevelopmental disorder, while also suggesting that collectively considering neuroimaging measures from multiple brain regions provides improved insight into the diversity of brain measures in autism that is not observed when considering the same regions separately. Distinguishing multidimensional brain relationships may thus be informative for identifying neuroimaging-based phenotypes, as well as help elucidate underlying neural mechanisms of brain variation in autism spectrum disorders.

Intact Prototype Formation but Impaired Generalization in Autism

Cognitive processing in autism has been characterized by a difficulty with the abstraction of information across multiple stimuli or situations and subsequent generalization to new stimuli or situations. This apparent difficulty leads to the suggestion that prototype formation, a process of creating a mental summary representation of multiple experienced stimuli that go together in a category, may be impaired in autism. Adults with high functioning autism and a typically developing comparison group matched on age and IQ completed a random dot pattern categorization task. Participants with autism demonstrated intact prototype formation in all four ways it was operationally defined, and this performance was not significantly different from that of control participants. However, participants with autism categorized dot patterns that were more highly distorted from the category prototypes less accurately than did control participants. These findings suggest, at least within the constraints of the random dot pattern task, that although prototype formation may not be impaired in autism, difficulties may exist with the generalization of what has been learned about a category to novel stimuli, particularly as they become less similar to the category's prototype.

Functional connectivity targeting for deep brain stimulation in essential tremor

BACKGROUND AND PURPOSE

Deep brain stimulation of the thalamus has become a valuable treatment for medication-refractory essential tremor, but current targeting provides only a limited ability to account for individual anatomic variability. We examined whether functional connectivity measurements among the motor cortex, superior cerebellum, and thalamus would allow discrimination of precise targets useful for image guidance of neurostimulator placement.

MATERIALS AND METHODS

Resting BOLD images (8 minutes) were obtained in 58 healthy adolescent and adult volunteers. Regions of interest were identified from an anatomic atlas and a finger movement task in each subject in the primary motor cortex and motor activation region of the bilateral superior cerebellum. Correlation was measured in the time series of each thalamic voxel with the 4 seeds. An analogous procedure was performed on a single subject imaged for 10 hours to constrain the time needed for single-subject optimization of thalamic targets.

RESULTS

Mean connectivity images from 58 subjects showed precisely localized targets within the expected location of the ventral intermediate nucleus of the thalamus, within a single voxel of currently used deep brain stimulation anatomic targets. These targets could be mapped with single-voxel accuracy in a single subject with 3 hours of imaging time, though targets were reproduced in different locations for the individual than for the group averages.

CONCLUSIONS

Interindividual variability likely exists in optimal placement for thalamic deep brain stimulation targeting of the cerebellar thalamus for essential tremor. Individualized thalamic targets can be precisely estimated for image guidance with sufficient imaging time.

Reproducibility of single-subject functional connectivity measurements

BACKGROUND AND PURPOSE

Measurements of resting-state functional connectivity have increasingly been used for characterization of neuropathologic and neurodevelopmental populations. We collected data to characterize how much imaging time is necessary to obtain reproducible quantitative functional connectivity measurements needed for a reliable single-subject diagnostic test.

MATERIALS AND METHODS

We obtained 100 five-minute BOLD scans on a single subject, divided into 10 sessions of 10 scans each, with the subject at rest or while watching video clips of cartoons. These data were compared with resting-state BOLD scans from 36 healthy control subjects by evaluating the correlation between each pair of 64 small spheric regions of interest obtained from a published functional brain parcellation.

RESULTS

Single-subject and group data converged to reliable estimates of individual and population connectivity values proportional to 1 / sqrt(n). Dramatic improvements in reliability were seen by using ≤25 minutes of imaging time, with smaller improvements for additional time. Functional connectivity "fingerprints" for the individual and population began diverging at approximately 15 minutes of imaging time, with increasing reliability even at 4 hours of imaging time. Twenty-five minutes of BOLD imaging time was required before any individual connections could reliably discriminate an individual from a group of healthy control subjects. A classifier discriminating scans during which our subject was resting or watching cartoons was 95% accurate at 10 minutes and 100% accurate at 15 minutes of imaging time.

CONCLUSIONS

An individual subject and control population converged to reliable different functional connectivity profiles that were task-modulated and could be discriminated with sufficient imaging time.

Decreased left posterior insular activity during auditory language in autism

BACKGROUND AND PURPOSE

Individuals with autism spectrum disorders often exhibit atypical language patterns, including delay of speech onset, literal speech interpretation, and poor recognition of social and emotional cues in speech. We acquired functional MR images during an auditory language task to evaluate systematic differences in language-network activation between control and high-functioning autistic populations.

MATERIALS AND METHODS

Forty-one right-handed male subjects (26 high-functioning autistic subjects, 15 controls) were studied by using an auditory phrase-recognition task, and areas of differential activation between groups were identified. Hand preference, verbal intelligence quotient (IQ), age, and language-function testing were included as covariables in the analysis.

RESULTS

Control and autistic subjects showed similar language-activation networks, with 2 notable differences. Control subjects showed significantly increased activation in the left posterior insula compared with autistic subjects (P < .05, false discovery rate), and autistic subjects showed increased bilaterality of receptive language compared with control subjects. Higher receptive-language scores on standardized testing were associated with greater activation of the posterior aspect of the left Wernicke area. A higher verbal IQ was associated with greater activation of the bilateral Broca area and involvement of the prefrontal cortex and lateral premotor cortex.

CONCLUSIONS

Control subjects showed greater activation of the posterior insula during receptive language, which may correlate with impaired emotive processing of language in autism. Subjects with autism showed greater bilateral activation of receptive-language areas, which was out of proportion to the differences in hand preference in autism and control populations.

Chronic stability and selectivity of four-contact spiral nerve-cuff electrodes in stimulating the human femoral nerve

This study describes the stability and selectivity of four-contact spiral nerve-cuff electrodes implanted bilaterally on distal branches of the femoral nerves of a human volunteer with spinal cord injury as part of a neuroprosthesis for standing and transfers. Stimulation charge threshold, the minimum charge required to elicit a visible muscle contraction, was consistent and low (mean threshold charge at 63 weeks post-implantation: 23.3 +/- 8.5 nC) for all nerve-cuff electrode contacts over 63 weeks after implantation, indicating a stable interface with the peripheral nervous system. The ability of individual nerve-cuff electrode contacts to selectively stimulate separate components of the femoral nerve to activate individual heads of the quadriceps was assessed with fine-wire intramuscular electromyography while measuring isometric twitch knee extension moment. Six of eight electrode contacts could selectively activate one head of the quadriceps while selectively excluding others to produce maximum twitch responses of between 3.8 and 8.1 N m. The relationship between isometric twitch and tetanic knee extension moment was quantified, and selective twitch muscle responses scaled to between 15 and 35 N m in tetanic response to pulse trains with similar stimulation parameters. These results suggest that this nerve-cuff electrode can be an effective and chronically stable tool for selectively stimulating distal nerve branches in the lower extremities for neuroprosthetic applications.

Origin of synchronized low-frequency blood oxygen level-dependent fluctuations in the primary visual cortex

BACKGROUND AND PURPOSE

Low-frequency (<0.08 Hz) fluctuations in spontaneous blood oxygen level-dependent (BOLD) signal intensity show synchronization across anatomically interconnected and functionally specific brain regions, suggesting a neural origin of fluctuations. To determine the mechanism by which high-frequency neural activity results in low-frequency BOLD fluctuations, I obtained measurements of the effects of neurovascular coupling on the frequency content of BOLD fluctuations.

MATERIALS AND METHODS

3T recordings of BOLD signal intensity in the primary visual cortex were obtained in response to visual stimuli presented at varying temporal frequencies to determine which stimulus frequencies were successfully transmitted to BOLD signal intensity. Additional BOLD time series recordings were performed in a resting state and during natural visual stimulation, and frequencies comprising BOLD fluctuations were measured. Magnetoencephalographic (MEG) time series recordings were obtained in a resting state to measure which components of MEG signal intensity best correlated in frequency distribution to observed BOLD fluctuations.

RESULTS

Visually driven oscillations in BOLD signal intensity were observed up to 0.2 Hz, representing a mismatch between low-pass filter properties of neurovascular coupling and observed frequencies of spontaneous BOLD fluctuations, which are <0.05 Hz in the primary visual cortex. Visual stimulation frequencies of >0.2 Hz resulted in frequency-dependent increases in mean BOLD response. Amplitude modulation of high-frequency neural activity was measured in MEG time series data, which demonstrated 1/frequency distribution with the greatest power comprising frequencies <0.05 Hz, consistent with the distribution of observed BOLD fluctuations.

CONCLUSION

Synchronized low-frequency BOLD fluctuations likely arise from a combination of vascular low-pass filtering and low-frequency amplitude modulation of neural activity.

Blind sampling is superior to anoscope guided sampling for screening for anal intraepithelial neoplasia

OBJECTIVES

Anal cytology smears are either collected "blind" (swab inserted 4 cm into anal canal and rotated) or guided through an anoscope (transformation zone visualised and then sampled). We compared these smear techniques with respect to sample quality and patient acceptability.

METHODS

Using a paired, random sequence clinical trial, 151 homosexual men (n = 95 HIV positive) underwent both smear techniques at a single visit; smear order was randomised and specimens were read blind. Both techniques utilised a Dacron swab, with water lubrication. Cytological specimens were prepared using a liquid based collection method (ThinPrep). The outcome measures were cytological specimen adequacy, cytological classification, presence of rectal columnar, squamous and metaplastic cells, contamination, patient comfort and acceptability, and volume of fluid that remained after the ThinPrep procedure.

RESULTS

Regardless of smear order, guided smears were less likely to detect higher grade abnormalities than blind smears (15 v 27 cases, p = 0.001). Controlling for smear order, guided smears were more likely to be assessed as "unsatisfactory" for cytological assessment (OR 6.93, 95% CI 1.92 to 24.94), and contain fewer squamous (OR 0.20, 95% CI 0.04 to 0.94) and metaplastic cells (OR 0.12, 95% CI 0.03 to 0.54) than blind smears; there were no other statistically significant differences between techniques. Regardless of smear technique, first performed smears were more likely to detect a higher grade abnormality than second performed smears (23 v eight cases, p < 0.001).

CONCLUSIONS

Blind cytology smears are superior to anoscope guided smears for screening for anal neoplasia in homosexual men.

PROSPECT improves cis-acting regulatory element prediction by integrating expression profile data with consensus pattern searches

Consensus pattern and matrix-based searches designed to predict cis-acting transcriptional regulatory sequences have historically been subject to large numbers of false positives. We sought to decrease false positives by incorporating expression profile data into a consensus pattern-based search method. We have systematically analyzed the expression phenotypes of over 6000 yeast genes, across 121 expression profile experiments, and correlated them with the distribution of 14 known regulatory elements over sequences upstream of the genes. Our method is based on a metric we term probabilistic element assessment (PEA), which is a ranking of potential sites based on sequence similarity in the upstream regions of genes with similar expression phenotypes. For eight of the 14 known elements that we examined, our method had a much higher selectivity than a naïve consensus pattern search. Based on our analysis, we have developed a web-based tool called PROSPECT, which allows consensus pattern-based searching of gene clusters obtained from microarray data.

Dynamics of the orientation-tuned membrane potential response in cat primary visual cortex

Neurons in the primary visual cortex are highly selective for stimulus orientation, whereas their thalamic inputs are not. Much controversy has been focused on the mechanism by which cortical orientation selectivity arises. Although an increasing amount of evidence supports a linear model in which orientation selectivity is conferred upon visual cortical cells by the alignment of the receptive fields of their thalamic inputs, the controversy has recently been rekindled with the suggestion that late cortical input--delayed by multiple synapses--could lead to sharpening of orientation selectivity over time. Here we used intracellular recordings in vivo to examine temporal properties of the orientation-selective response to flashed gratings. Bayesian parameter estimation demonstrated that both preferred orientation and tuning width were stable throughout the response to a single stimulus.

Signalling and non-caveolar rafts

Rafts are small membrane domains containing discrete subsets of lipids and proteins. Although microscopic raft structures termed 'caveolae' were described nearly 50 years ago, the importance of rafts, particularly signalling within rafts, is only beginning to be understood. Our studies focus on receptor-dependent phosphoinositide signalling. Using their characteristic buoyancy in density gradients, we and others found that the epidermal growth factor (EGF) receptor, phosphatidylinositol 4-kinase and phosphoinositides are localized within a caveolin-rich fraction of A431 carcinoma cells. We subsequently found that membrane fragments containing the EGF receptor and most cellular phosphoinositides can be separated from caveolae. Consequently, components of EGF-dependent phosphoinositide signalling localize to one or more novel types of raft, the composition of which we are currently determining. A key component is the type II phosphatidylinositol 4-kinase, which, for many years, has proven difficult to purify and clone. We describe our recent purification from rafts and cloning of this elusive enzyme, and discuss how the structure sheds light on the rafting of this enzyme.

Cloning of a human type II phosphatidylinositol 4-kinase reveals a novel lipid kinase family

Phosphoinositide lipids regulate numerous cellular processes in all eukaryotes. The versatility of this phospholipid is provided by combinations of phosphorylation on the 3', 4', and 5' positions of the inositol head group. Two distinct structural families of phosphoinositide (PI) kinases have so far been identified and named after their prototypic members, the PI 3-kinase and phosphatidylinositol (PtdIns) phosphate kinase families, both of which have been found to contain structural homologues possessing PI 4-kinase activity. Nevertheless, the prevalent PtdIns 4-kinase activity in many mammalian cell types is conferred by the widespread type II PtdIns 4-kinase, which has so far resisted molecular characterization. We have partially purified the human type II isoform from plasma membrane rafts of human A431 epidermoid carcinoma cells and obtained peptide mass and sequence data. The results allowed the cDNA containing the full open reading frame to be cloned. The predicted amino acid sequence revealed that the type II enzyme is the prototypic member of a novel, third family of PI kinases. We have named the purified protein type IIalpha and a second human isoform, type IIbeta. The type IIalpha mRNA appears to be expressed ubiquitously in human tissues, and homologues appear to be expressed in all eukaryotes.

The phylogenetic trunk: maximal inclusion of taxa with missing data in an analysis of the lepospondyli (Vertebrata, Tetrapoda)

The importance of fossils to phylogenetic reconstruction is well established. However, analyses of fossil data sets are confounded by problems related to the less complete nature of the specimens. Taxa that are incompletely known are problematic because of the uncertainty of their placement within a tree, leading to a proliferation of most-parsimonious solutions and "wild card" behavior. Problematic taxa are commonly deleted based on a priori criteria of completeness. Paradoxically, a taxon's problematic behavior is tree dependent, and levels of completeness are not directly associated with problematic behavior. Exclusion of taxa on the basis of completeness eliminates real character conflict and, by not allowing incomplete taxa to determine tree topology, diminishes the phylogenetic hypothesis. Here, the phylogenetic trunk approach is proposed to allow optimization of taxonomic inclusion and tree stability. The use of this method in an analysis of the Paleozoic Lepospondyli finds a single most-parsimonious tree, or trunk, after the removal of one taxon identified as being problematic. Moreover, the 38 trees found at one additional step from this primary trunk were reduced to 2 by removal of one additional taxon. These trunks are compared with the trees that were found by excluding taxa with various degrees of completeness, and the effects of incomplete taxa are explored with regard to use of the trunk. Correlated characters associated with limblessness are discussed regarding the assumption of character independence; however, inclusion of intermediate taxa is found to be the single best method for breaking down long branches.

Prediction of orientation selectivity from receptive field architecture in simple cells of cat visual cortex

From the intracellularly recorded responses to small, rapidly flashed spots, we have quantitatively mapped the receptive fields of simple cells in the cat visual cortex. We then applied these maps to a feedforward model of orientation selectivity. Both the preferred orientation and the width of orientation tuning of the responses to oriented stimuli were well predicted by the model. Where tested, the tuning curve was well predicted at different spatial frequencies. The model was also successful in predicting certain features of the spatial frequency selectivity of the cells. It did not successfully predict the amplitude of the responses to drifting gratings. Our results show that the spatial organization of the receptive field can account for a large fraction of the orientation selectivity of simple cells.

Membrane potential and conductance changes underlying length tuning of cells in cat primary visual cortex

Spike responses for many cells of cat primary visual cortex are optimized for the length of a drifting grating stimulus. Stimuli that are longer or shorter than this optimal length elicit submaximal spike responses. To investigate the mechanisms responsible for this length tuning, we have recorded intracellularly from visual cortical neurons in the cat while presenting drifting grating stimuli of varying lengths. We have found that the membrane potential responses of the cells also exhibit length tuning, but that the suppression of spike responses at lengths longer than the preferred is 30-50% stronger than the corresponding suppression of the membrane potential responses. This difference may be attributed to the effects of spike threshold. Furthermore, using steady injected currents, we have measured changes in the excitatory and inhibitory components of input conductance evoked by stimuli of different lengths. We find that, compared with optimal stimuli, long stimuli evoke both an increase in inhibitory conductance and a decrease in excitatory conductance. These two mechanisms differ in their contrast sensitivity, resulting in stronger end stopping and shorter optimal lengths for high-contrast stimuli. These patterns suggest that response suppression for long stimuli is generated by a combination of active inhibition from stimuli outside the excitatory receptive field, as well as decreased excitation from other cortical cells that are themselves end-inhibited.

Thyroglobulin messenger ribonucleic acid levels in the peripheral blood of children with benign and malignant thyroid disease

Reverse transcriptase-PCR has identified thyroglobulin mRNA (Tg mRNA) in peripheral blood of normal adults and adults with thyroid cancer. However, no children were studied. The primary objective of this study was to determine whether whole blood Tg mRNA levels differ between benign and malignant thyroid disease in children. The secondary goals were to determine whether whole blood Tg mRNA levels vary with age or pubertal development among children with thyroid disease. Whole blood Tg mRNA levels were determined in 38 children (29 girls, nine boys; median age, 14.5 y; range, 4.8-20.4 y) with benign and malignant thyroid disease and correlated with diagnosis, age, pubertal status, thyroid size, and serum levels of free thyroxine, TSH, and Tg protein. Tg mRNA levels ranged from 3.3 to 104 pg Eq/microg total thyroid RNA (mean, 28 +/- 20.2 pg Eq/microg total thyroid RNA) and were similar in benign and malignant disorders (p = 0.67). However, in children with previously treated papillary thyroid cancer, Tg mRNA levels directly correlated with total body (131)I uptake (p = 0.026) and serum Tg protein (p = 0.037). There was no difference between boys and girls, and no change with pubertal maturation. In children with benign thyroid disease, Tg mRNA levels correlated with serum TSH (p = 0.031), but not with diagnosis, age, Tanner stage, or thyroid size. We conclude that Tg mRNA levels are similar in children with benign and malignant thyroid disease and unchanged by age or pubertal status, but correlated with tumor burden in previously treated papillary thyroid cancer.

The contribution of noise to contrast invariance of orientation tuning in cat visual cortex

Feedforward models of visual cortex appear to be inconsistent with a well-known property of cortical cells: contrast invariance of orientation tuning. The models' fixed threshold broadens orientation tuning as contrast increases, whereas in real cells tuning width is invariant with contrast. We have compared the orientation tuning of spike and membrane potential responses in single cells. Both are contrast invariant, yet a threshold-linear relation applied to the membrane potential accurately predicts the orientation tuning of spike responses. The key to this apparent paradox lies in the noisiness of the membrane potential. Responses that are subthreshold on average are still capable of generating spikes on individual trials. Unlike the iceberg effect, contrast invariance remains intact even as threshold narrows orientation selectivity. Noise may, by extension, smooth the average relation between membrane potential and spike rate throughout the brain.

Cooperative ordering in homeodomain-DNA recognition: solution structure and dynamics of the MATa1 homeodomain

The mating type homeodomain proteins, MATa1 and MATalpha2, combine to form a heterodimer to bind DNA in diploid yeast cells. The a1-alpha2 heterodimer tightly and specifically binds haploid-specific gene operators to repress transcription. On its own, however, the a1 homeodomain does not bind DNA in a sequence-specific manner. To help understand this interaction, we describe the solution structure and backbone dynamics of the free a1 homeodomain. Free a1 in solution is an ensemble of structures having flexible hinges at the two turns in the small protein fold. Conformational changes in the a1 homeodomain upon ternary complex formation are located in the loop between helix 1 and helix 2, where the C-terminal tail of alpha2 binds to form the heterodimer, and at the C-terminus of helix 3, the DNA recognition helix. The observed differences, comparing the free and bound a1 structures, suggest a mechanism linking van der Waals stacking changes to the ordering of a final turn in the DNA-binding helix of a1. The tail of alpha2 induces changes in loop 1 of a1 that push it toward a properly folded DNA binding conformation.

Orientation tuning of input conductance, excitation, and inhibition in cat primary visual cortex

The input conductance of cells in the cat primary visual cortex (V1) has been shown recently to grow substantially during visual stimulation. Because increasing conductance can have a divisive effect on the synaptic input, theoretical proposals have ascribed to it specific functions. According to the veto model, conductance increases would serve to sharpen orientation tuning by increasing most at off-optimal orientations. According to the normalization model, conductance increases would control the cell's gain, by being independent of stimulus orientation and by growing with stimulus contrast. We set out to test these proposals and to determine the visual properties and possible synaptic origin of the conductance increases. We recorded the membrane potential of cat V1 cells while injecting steady currents and presenting drifting grating patterns of varying contrast and orientation. Input conductance grew with stimulus contrast by 20-300%, generally more in simple cells (40-300%) than in complex cells (20-120%), and in simple cells was strongly modulated in time. Conductance was invariably maximal for stimuli of the preferred orientation. Thus conductance changes contribute to a gain control mechanism, but the strength of this gain control does not depend uniquely on contrast. By assuming that the conductance changes are entirely synaptic, we further derived the excitatory and inhibitory synaptic conductances underlying the visual responses. In simple cells, these conductances were often arranged in push-pull: excitation increased when inhibition decreased and vice versa. Excitation and inhibition had similar preferred orientations and did not appear to differ in tuning width, suggesting that the intracortical synaptic inputs to simple cells of cat V1 originate from cells with similar orientation tuning. This finding is at odds with models where orientation tuning in simple cells is achieved by inhibition at off-optimal orientations or sharpened by inhibition that is more broadly tuned than excitation.

Quantitative reverse transcription-polymerase chain reaction of circulating thyroglobulin messenger ribonucleic acid for monitoring patients with thyroid carcinoma

Patients with thyroid cancer are monitored for disease recurrence by measurement of serum thyroglobulin (Tg) and iodine-131 (131I) scanning. To enhance sensitivity and to circumvent antibodies that interfere with Tg immunoassays, we have developed RT-PCR assays that detect circulating thyroid messenger RNA (mRNA) transcripts. We now report results using a sensitive quantitative Tg mRNA assay (Taqman; ABI, Foster City, CA) in comparison with immunoassay in patients previously treated for thyroid cancer. We evaluated 107 patients: 84 during T4 therapy, 14 after T4 withdrawal, and 9 at both time points. All patients had near-total thyroidectomy, and 92% received postoperative 131I. Serum TSH, Tg protein, and Tg mRNA were measured. Patients were grouped based on most recent 131I scan or pathologically confirmed disease as having no detectable thyroid tissue (n = 33), thyroid bed uptake (n = 37), cervical/regional adenopathy (n = 21), or distant metastases (n = 16). During T4 therapy, median (range) Tg mRNA values (pg Tg Eq/microg thyroid RNA) for the groups were 1.5 (0-26.8), 9.4 (0.5-90.0), 15.4 (0.2-92), and 12.4 (1.9-16.6), respectively. Using a value of 3 pg Tg Eq/microg thyroid RNA as cut-point, Tg mRNA was positive in 38% of patients with no uptake, 75% with thyroid bed uptake, 84% with cervical/regional disease, and 94% with distant metastases. The median Tg mRNA value for patients with no uptake was lower than the median values for patients with thyroid bed uptake (P = 0.009) or with detectable thyroid tissue at any site (P = 0.010). Patients with negative 131I whole body scans were also less likely to have detectable Tg mRNA levels than were patients with thyroid bed uptake (P < 0.001) or any detectable thyroid tissue at any location (P < 0.001). Similar differences between these groups were seen after T4 withdrawal and for the 23 patients with circulating anti-Tg antibodies, when analyzed separately. Eight of the nine patients studied with low and high TSH concentrations displayed greater amounts of circulating Tg mRNA after T4 withdrawal. In three patients followed prospectively, the amount Tg mRNA correlated with the presence and absence of cervical metastases. In conclusion, we have demonstrated that a quantitative Tg mRNA assay can identify thyroid cancer patients with recurrent or residual thyroid tissue with greater sensitivity and similar specificity to Tg immunoassay during T4 therapy. The assay was unaffected by anti-Tg antibodies, responded to TSH-stimulation, and was reduced after surgical removal of metastases. These data suggest that this quantitative Tg mRNA assay may be a sensitive marker of tumor recurrence or response to therapy, particularly in patients with anti-Tg antibodies.

Quantitative reverse transcription-PCR measurement of thyroglobulin mRNA in peripheral blood of healthy subjects

BACKGROUND

Thyroglobulin mRNA can be detected qualitatively in the peripheral blood of patients with metastatic thyroid cancer, thyroid cancer patients with residual thyroid bed uptake, and individuals with no known thyroid disease with intact thyroid glands by use of a lengthy, highly sensitive extraction technique. To improve and broaden the clinical usefulness of this assay, we developed a quantitative reverse transcription (RT)-PCR assay for thyroglobulin mRNA, using RNA recovered from whole blood with a simplified extraction technique.

METHODS

Whole blood was drawn from 32 healthy subjects in standard EDTA blood collection tubes. Total RNA was extracted from whole blood, using the PUREscript RNA Isolation Kit. RT-PCR using intron-spanning primers was used to quantitatively amplify thyroglobulin mRNA, using the ABI PRISM 7700 Sequence Detection System with a fluorescent-labeled, thyroglobulin-specific oligonucleotide probe. Thyroid RNA calibration curves were created using total RNA recovered from a single nondiseased thyroid gland.

RESULTS

Qualitative RT-PCR demonstrated the presence of thyroglobulin mRNA in the whole blood sample of each healthy subject. The mean concentration of thyroglobulin mRNA detected in these subjects was 433 +/- 69 ng of total thyroid RNA per liter of whole blood (range, 26-1502 ng/L). Overall assay imprecision (CV) was 24% for five samples analyzed 10 times each in separate analytical runs on different days.

CONCLUSIONS

Thyroglobulin mRNA can be accurately detected and quantified in peripheral blood from healthy subjects. This new quantitative technique may improve the clinical utility of circulating thyroglobulin mRNA detection in patients with thyroid disease.

Joubert's syndrome and prenatal hydrocephalus

Joubert's syndrome is an autosomal-recessive condition characterized by dysgenesis of the cerebellar vermis, hypotonia, developmental delay, a respiratory pattern of alternating tachypnea and apnea, and abnormal eye movements. Radiologic findings include a midline cerebellar cleft in place of the vermis and a characteristic shape of the fourth ventricle. Prenatal hydrocephalus has been proposed as a possible etiology for the cerebellar abnormalities but has not previously been described in association with this syndrome. The authors report a patient with clinical and radiographic features consistent with Joubert's syndrome who presented with congenital hydrocephalus.

Tarsal abnormalities: a new grading system

PURPOSE

The 5-stage scale currently used to grade tarsal conjunctiva is limited with respect to precisely describing the tissue condition and accurately following small changes. We conducted two preliminary studies to evaluate a new 8-stage, photographic tarsal conjunctival grading system.

METHODS

We conducted a retrospective review of the records of 145 individuals in Denmark who had successfully worn Acuvue lenses for at least six months on a daily wear basis. Patients wore Acuvue lenses on a two-week replacement schedule and used one of four different care systems (AOSEPT, OPTI-FREE, OXYSEPT, and RENU). Tarsal conjunctiva and lens cleanliness were graded by the investigators. Comfort, vision, and simplicity of care system were rated by the patients. In the second, prospective study, a group of 30 patients who had successfully worn Acuvue lenses and used the OPTI-FREE care system for at least six months were followed for three months to test the repeatability of the new grading system.

RESULTS

In the first study, patients using RENU were found to have significantly higher scores than AOSEPT and OPTI-FREE patients when comparing tarsal scores based on the 5-stage scale (P < 0.05). When comparing scores based on the 8-stage scale, significant differences were detected between RENU and all three of the other care systems, with RENU scores being higher (P < 0.05). Numerous differences were found among care systems in lens cleanliness and subjective patient ratings of comfort, vision, and simplicity of use. In the second study, tarsal scores did not change over time in the patients followed for three months.

CONCLUSIONS

These initial studies suggest that the new grading scale may allow for more precise determination of the condition of the tarsal conjunctiva and provide for a greater ability to detect differences among lens care regimens in tarsal conjunctival scores. Early indications are that the scale is reliable and repeatable.

The crk3 gene of Leishmania mexicana encodes a stage-regulated cdc2-related histone H1 kinase that associates with p12

A cdc2-related protein kinase gene, crk3, has been isolated from the parasitic protozoan Leishmania mexicana. Data presented here suggests that crk3 is a good candidate to be the leishmanial cdc2 homologue but that the parasite protein has some characteristics which distinguish it from mammalian cdc2. crk3 is predicted to encode a 35.6-kDa protein with 54% sequence identity with the human cyclin-dependent kinase cdc2 and 78% identity with the Trypanosoma brucei CRK3. The trypanosomatid CRK3 proteins have an unusual, poorly conserved 19-amino acid N-terminal extension not present in human cdc2. crk3 is single copy, and there is 5-fold higher mRNA in the replicative promastigote life-cycle stage than in the non-dividing metacyclic form or mammalian amastigote form. A leishmanial suc-binding cdc2-related kinase (SBCRK) histone H1 kinase, has previously been described which binds the yeast protein, p13(suc1), and that has stage-regulated activity (Mottram J. C., Kinnaird, J., Shiels, B. R., Tait, A., and Barry, J. D. (1993) J. Biol. Chem. 268, 21044-21051). CRK3 from cell extracts of the three life-cycle stages was found to bind p13(suc1) and the leishmanial homologue p12(cks1). CRK3 fused with six histidines at the C terminus was expressed in L. mexicana and shown to have SBCRK histone H1 kinase activity. Depletion of histidine-tagged CRK3 from L. mexicana cell extracts, by Ni-nitrilotriacetic acid agarose selection, reduced histone H1 kinase activity binding to p13(suc1). These data imply that crk3 encodes the kinase subunit of SBCRK. SBCRK and histidine-tagged CRK3 activities were inhibited by the purine analogue olomoucine with an IC50 of 28 and 42 microM, respectively, 5-6-fold higher than human p34(cdc2)/cyclinB.

The 3' to 5' degradation of yeast mRNAs is a general mechanism for mRNA turnover that requires the SKI2 DEVH box protein and 3' to 5' exonucleases of the exosome complex

One major pathway of mRNA decay in yeast occurs by deadenylation-dependent decapping, which exposes the transcript to 5' to 3' exonucleolytic degradation. We show that a second general pathway of mRNA decay in yeast occurs by 3' to 5' degradation of the transcript. We also show that the SKI2, SKI3, SKI6/RRP41, SKI8 and RRP4 gene products are required for 3' to 5' decay of mRNA. The Ski6p/Rrp41p protein has homology to the Escherichia coli 3' to 5' exoribonuclease RNase PH, and both the Ski6p/Rrp41p and Rrp4p proteins are components of a multiprotein complex, termed the exosome, that contains at least three polypeptides with 3' to 5' exoribonuclease activities. These observations suggest that the exosome may be the nucleolytic activity that degrades the body of the mRNA in a 3' to 5' direction, and the exosome's activity on mRNAs may be modulated by Ski2p, Ski3p and Ski8p. Blocking both 3' to 5' and 5' to 3' decay leads to inviability, and conditional double mutants show extremely long mRNA half-lives. These observations argue that efficient mRNA turnover is required for viability and that we have identified the two major pathways of mRNA decay in yeast.

Protein-tyrosine phosphatase SHP-1 is dispensable for FcgammaRIIB-mediated inhibition of B cell antigen receptor activation

The inhibitory Fc receptor, FcgammaRIIB, provides a signal that aborts B cell antigen receptor activation, blocking extracellular calcium influx. Because the protein-tyrosine phosphatase SHP-1 binds tyrosyl phosphorylated FcgammaRIIB and FcgammaRIIB-mediated inhibition is defective in motheaten (me/me) mice, which do not express SHP-1, it was proposed that SHP-1 mediates FcgammaRIIB signaling in B cells (D'Ambrosio, D., Hippen, K. L., Minskoff, S. A., Mellman, I., Pani, G., Siminovitch, K. A., and Cambier, J. C. (1995) Science 268, 293-297). However, SHP-1 is dispensable for FcgammaRIIB-mediated inhibition of FcepsilonRI signaling in mast cells (Ono, M., Bolland, S., Tempst, P., and Ravetch, J. V. (1996) Nature 383, 263-266), prompting us to re-examine the role of SHP-1 in FcgammaRIIB signaling in B cells. We generated immortalized sIgM+, FcgammaRIIB+ cell lines from me/me mice and normal littermates. Co-ligation of FcgammaRIIB and the sIgM antigen receptor inhibits calcium influx in both cell lines. Inhibition is reversed by preincubation with anti-FcgammaRIIB antibodies, indicating that it is mediated by FcgammaRIIB. The inositol 5' phosphatase SHIP is recruited to tyrosyl-phosphorylated FcgammaRIIB in both cell lines. FcgammaRIIB-mediated CD19 dephosphorylation also occurs in the presence or the absence of SHP-1. Our results establish that SHP-1 is dispensable for FcgammaRIIB-mediated inhibition of sIgM antigen receptor signaling.

The quality of life of persons with chronic fatigue syndrome

This descriptive study used a between-methods triangulation design to analyze the multiple dimensions of quality of life in persons with chronic fatigue syndrome (CFS). This method, which refers to the combination of both quantitative and qualitative methods in the same study, allowed the authors to obtain more comprehensive and robust data than could be obtained by either method alone. A convenience sample of 110 persons with CFS completed the quality of life index and CFS questionnaire, and a subset of 22 persons were interviewed regarding their lived experience with CFS. Overall scores on the quality of life index were significantly lower in CFS than for other chronic illness groups. Subjects reported the lowest quality of life scores in health and functioning domain. Indepth interviews provided a more complete understanding of the quality of life in CFS and further explained the low ratings that were found on the quality of life index. The findings suggest that quality of life is particularly and uniquely disrupted in CFS.

Arterial cannulation: how to do it

The use of arterial lines is now common in the care of critically ill patients. Intra-arterial cannulation with continuous blood pressure transduction and display remains the accepted standard for comprehensive arterial blood pressure monitoring. This article will illustrate a technique for percutaneous radial artery cannulation as well as outlining the indications, contraindications and possible complications of arterial cannulation.

Biosynthesis of teichuronic acid in the bacterial cell wall. Purification and characterization of the glucosyltransferase of Micrococcus luteus

This report describes what is, to our knowledge, the first purification to near homogeneity of an enzyme involved in the biosynthesis of the teichuronic acid of Micrococcus luteus cell walls. The glucosyltransferase of M. luteus, which participates in the biosynthesis of teichuronic acid, was solubilized from cytoplasmic membrane fragments by extraction with buffer solutions containing the detergents Thesit (dodecyl alcohol polyoxyethylene ether; 1 mg/ml) and 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (0.5 mg/ml). The detergent-solubilized enzyme was purified 150-fold, with a recovery of 13% by adsorbent column chromatography, ion-exchange chromatography, gel filtration, and preparative nondenaturing gradient polyacrylamide gel electrophoresis. On the basis of its mobility on native gradient gel, the glucosyltransferase was estimated to have a molecular mass of 440 kDa. The purified native enzyme was a multisubunit protein consisting of subunits of two sizes; their molecular masses were determined to be 52.5 and 54 kDa, respectively, by observation of the mobility of the protein bands in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point of the enzyme was approximately 5.

An essential role for Bruton's [corrected] tyrosine kinase in the regulation of B-cell apoptosis

Mutations of the Bruton's tyrosine kinase (btk) gene cause X-linked agammaglobulinemia (XLA) in humans and X-linked immune deficiency (Xid) in mice. To establish the BTK role in B-cell activation we examined the responses of wild-type and Xid B cells to stimulation through surface IgM and CD40, the transducers of thymus independent-type 2 and thymus-dependent activation, respectively. Wild-type BTK was necessary for proliferation induced by soluble anti-IgM (a prototype for thymus independent-type 2 antigen), but not for responses to soluble CD40 ligand (CD40L, the B-cell activating ligand expressed on T-helper cells). In the absence of wild-type BTK, B cells underwent apoptotic death after stimulation with anti-IgM. In the presence of wild-type but not mutated BTK, anti-IgM stimulation reduced apoptotic cell death. In contrast, CD40L increased viability of both wild-type and Xid B cells. Importantly, viability after stimulation correlated with the induced expression of bcl-XL. In fresh ex vivo small resting B cells from wild-type mice there was only barely detectable bcl-XL protein, but there was more in the larger, low-density ("activated") splenic B cells and peritoneal B cells. In vitro Bcl-XL induction following ligation of sIgM-required BTK, was cyclosporin A (CsA)-sensitive and dependent on extracellular Ca2+. CD40-mediated induction of bcl-x required neither wild-type BTK nor extracellular Ca2+ and was insensitive to CsA. These results indicate that BTK lies upstream of bcl-XL in the sIgM but not the CD40 activation pathway. bcl-XL is the first induced protein to be placed downstream of BTK.

Regional differences in bone density of young men involved in different exercises

In this cross-sectional, retrospective study, the bone mineral content (BMC) and density (BMD) of the whole skeleton, upper limbs, lower limbs, femoral neck, and lumbar vertebrae were measured using dual photon absorptiometry and the results compared in healthy young males involved in: weight-lifting, running, cross-training, or recreational exercises. When adjusted for body weight, the upper limb BMD was highest in those engaged solely in weight-lifting (mean 1.021, SE 0.019, and 95% CI 0.981-1.061) and lowest in runners (mean 0.908, SE 0.019 and 95% CI 0.869-0.946). These differences were significant (P = 0.0004). There were no significant differences in upper limb BMD between weight-lifters and cross-trained athletes and between runners and those engaged in recreational exercises. Significant differences in BMD were observed between weight-lifters and recreational athletes (P = 0.001) and between cross-trained athletes and runners (P = 0.03). No other significant differences were observed. These data suggest that healthy, young, adult males reporting a history of intensive weight-lifting had significantly greater bone mass of the upper limb bones than those reporting a history of non-weight-lifting exercises. These results imply a specific versus generalized effect of mechanical load on bones of the skeleton.

Structural requirements for the interaction between tissue factor and factor VII: characterization of chymotrypsin-derived tissue factor polypeptides

Tissue Factor (TF) is the cellular receptor for coagulation Factor VII/VIIa (FVII/VIIa). TF binds to FVIIa and promotes the rapid activation of the zymogen substrates Factors IX and X (FIX and FX) to the respective serine proteinases. In order to probe structure-function relationships in TF, we have subjected the truncated membrane-bound variant, TF 1-243, to proteolytic digestion in SDS-containing gels. Three major polypeptide fragments were generated by proteolysis of TF 1-243 with chymotrypsin, producing cleavages C-terminal to residues 34, 76 and 103. All three polypeptides, TF 35-243, 77-243 and 104-243, bound biotinylated human FVII in a highly specific ligand blot assay. High-performance electrophoretic chromatography was used to isolated chymotrypsin-derived fragments of TF. These purified fragments bound FVII in ligand blots, and two of the three polypeptides exhibited much reduced, but significant, procoagulant activity in a chromogenic assay for the generation of Factor Xa in the presence of FVIIa and Ca2+. The smallest chymotrypsin-derived TF polypeptide, TF 104-243, showed reduced binding of FVII in ligand blot analyses, inhibited the activity of the full-length molecule, but had no procoagulant activity. These data suggest that a part of the binding site for FVII is contained within the TF sequence 104-243. The sequence TF 1-34 either contains a part of the FVII-binding domain or its removal leads to dysfunctional folding, disrupting binding sites elsewhere in the molecule.

Effects of angiotensin converting enzyme inhibition with cilazapril on intimal hyperplasia in injured arteries and vascular grafts in the baboon

To determine the importance of angiotensin converting enzyme (ACE) activity in the development of arterial proliferative lesions in a primate model, the response to vascular injury was studied in five baboons treated with oral cilazapril (20 mg/kg/day) and in five untreated control animals. Each animal underwent three procedures: 1) carotid artery endarterectomy, 2) balloon catheter deendothelialization of the superficial femoral artery, and 3) surgical placement of bilateral aorto-iliac expanded polytetrafluoroethylene (Gore-Tex) vascular grafts. Cilazapril therapy was initiated 1 week preoperatively and continued throughout the study interval. At 1 and 3 weeks postoperatively, plasma ACE activity was inhibited by more than 96% versus control values. After animals were killed at 3 months, injured vessel and graft segments were evaluated morphometrically. Although the response between animals was variable, average cross-sectional areas of neointima did not differ between the cilazapril-treated and control groups at sites of carotid endarterectomy (0.26 +/- 0.12 versus 0.34 +/- 0.17 mm2, respectively; p greater than 0.5), femoral artery ballooning (0.15 +/- 0.08 versus 0.11 +/- 0.01 mm2; p greater than 0.5), or at graft anastomoses (1.86 +/- 0.50 versus 1.72 +/- 0.50 mm2; p greater than 0.5). Thus, cilazapril did not reduce intimal thickening over 3 months in these primate arterial injury models. However, a possible beneficial effect of cilazapril, which might be apparent at earlier time points or with larger animal groups, cannot be excluded.

Purification and characterization of factor VII 304-Gln: a variant molecule with reduced activity isolated from a clinically unaffected male

Factor VII (FVII) is the plasma serine protease zymogen which, on binding to its cellular receptor tissue factor (TF), initiates blood coagulation. A 47-year-old man with no clinical bleeding tendency was found to have undetectable plasma FVII activity when tested in a one-stage assay using rabbit brain TF, but 0.3 U/mL using recombinant human TF and 1.04 U/mL FVII antigen. Variant FVII purified from his plasma showed an identical migration on sodium dodecyl sulfate-polyacrylamide gel electrophoresis to wild-type zymogen. By enzyme kinetic analysis the Km of the variant using FX as a substrate was 12-fold higher than that of normal FVII. Also, the variant FVII was unable to compete with wild-type FVII for limited rabbit TF binding sites. A ligand blot procedure was used to directly demonstrate reduced binding of recombinant human TF to the variant FVII compared with normal FVII. Genetic analysis of leukocyte DNA showed a G to A mutation in the propositus' gene at codon 304 that results in the substitution of a glutamine for an arginine residue in the catalytic domain of the protease. We conclude that this region of the FVII molecule is important for its function.

Brain tumor resection aided with markers placed using stereotaxis guided by magnetic resonance imaging and computed tomography

In the operative resection of brain tumors, defining and locating edges of deep-seated tumors or those with indistinct color and consistency can be difficult. This report presents a simple yet precise, alternative method, using the basic Brown-Roberts-Wells or Cosman-Roberts-Wells stereotactic frame, for placement of visual markers to aid in tumor resections. The method can also be extended to the Leksell system. Using routine computed tomographic scanning or magnetic resonance imaging after stereotactic frame application, multiple points along tumor edges were used as target points. In the operating room, standard techniques were used for the skin incision, removal of the bone flap, and opening the dura. At each target point, after opening the dura and using stereotactic coordinates and equipment, a microbiopsy forceps was used to place "micropatties" (each with a string tail) or small catheters with pledgets or catheter tips located at tumor edges. After removing the arc, the tumor resection was accomplished in a conventional nonstereotactic manner by simply following string tails or catheters to the tumor. Gross tumor edges were determined from positions of actual patties or catheter tips. These simple but accurate techniques offer the possibility of tumor resections under stereotactic guidance with equipment readily available to most neurosurgeons. The fidelity of marker placement is also maintained in relation to tumor edges despite shifts in the tumor and/or brain as cystic areas are drained or large amounts of the tumor are resected.

Primary CNS malignant rhabdoid tumor (MRT): report of two cases and review of literature

Primary CNS rhabdoid tumor is an enigmatic and extremely rare malignant tumor of early childhood, probably embryonal, that has often been histopathologically classified together with rhabdoid tumor of kidneys or other organs in infants. Only four previously documented cases of primary CNS malignant rhabdoid tumor (MRT) were found in the literature. We report two cases of primary CNS MRT with biopsy and complete autopsy findings that share close clinicopathologic, immunohistochemical and ultrastructural similarities between the two. It is concluded that the primary CNS MRT is an entity which is extremely malignant, easily mistaken as a primitive neuroectodermal tumor, and potentially derives from a meningothelial precursor cell which is embryonally equal to the serosal mesothelial precursor cells which surround the kidneys and other organs. Hence, it tends to anatomically occur at the location of abundant meningeal infoldings such as the cerebellar cortex and may be diffuse or multicentric in its meningeal involvement. Furthermore, it may concurrently or multicentrically occur in association with MRT originating from the serosal membrane of other organs, such as the kidney.

Biosynthetic elongation of isolated teichuronic acid polymers via glucosyl- and N-acetylmannosaminuronosyltransferases from solubilized cytoplasmic membrane fragments of Micrococcus luteus

Cytoplasmic membrane fragments of Micrococcus luteus catalyze in vitro biosynthesis of teichuronic acid from uridine diphosphate D-glucose (UDP-glucose), uridine diphosphate N-acetyl-D-mannosaminuronic acid (UDP-ManNAcA), and uridine diphosphate N-acetyl-D-glucosamine. Membrane fragments solubilized with Thesit (dodecyl alcohol polyoxyethylene ether) can utilize UDP-glucose and UDP-ManNAcA to effect elongation of teichuronic acid isolated from native cell walls. When UDP-glucose is the only substrate supplied, the detergent-solubilized glucosyltransferase incorporates a single glucosyl residue onto each teichuronic acid acceptor. When both UDP-glucose and UDP-ManNAcA are supplied, the glucosyltransferase and the N-acetylmannosaminuronosyltransferase act cooperatively to elongate the teichuronic acid acceptor by multiple additions of the disaccharide repeat unit. As shown by polyacrylamide gel electrophoresis, low-molecular-weight fractions of teichuronic acid are converted to higher-molecular-weight polymers by the addition of as many as 17 disaccharide repeat units.

The Medical Outcomes Study Instrument (MOSI)--use of a new health status measure in Britain

The Medical Outcomes Study Instrument (MOSI), a 20 item functional health status measure was sent to all women aged 30-40 years (n = 486) in a General Practice (list size 6447). There was a 73% response rate to two mailings. Lower scores on all six dimensions of the MOSI were associated with the number of diagnoses and identified mental illness on the patient summaries, unemployment and with positive scores on the Nottingham Health Profile. In two categories, General Health Perceptions and Mental Health, the scores were lower for those on long-term medication. The paper suggests that the MOSI may be a candidate for Health Status measurement in research and audit in primary care, but further research is required.