The prefusion structure of herpes simplex virus glycoprotein B.

Cell entry of enveloped viruses requires specialized viral proteins that mediate fusion with the host membrane by substantial structural rearrangements from a metastable pre- to a stable postfusion conformation. This metastability renders the herpes simplex virus 1 (HSV-1) fusion glycoprotein B (gB) highly unstable such that it readily converts into the postfusion form, thereby precluding structural elucidation of the pharmacologically relevant prefusion conformation. By identification of conserved sequence signatures and molecular dynamics simulations, we devised a mutation that stabilized this form. Functionally locking gB allowed the structural determination of its membrane-embedded prefusion conformation at sub-nanometer resolution and enabled the unambiguous fit of all ectodomains. The resulting pseudo-atomic model reveals a notable conservation of conformational domain rearrangements during fusion between HSV-1 gB and the vesicular stomatitis virus glycoprotein G, despite their very distant phylogeny. In combination with our comparative sequence-structure analysis, these findings suggest common fusogenic domain rearrangements in all class III viral fusion proteins.

Role of the Streptomyces spore wall synthesizing complex SSSC in differentiation of Streptomyces coelicolor A3(2).

A crucial stage of the Streptomyces life cycle is the sporulation septation, a process were dozens of cross walls are synchronously formed in the aerial hyphae in a highly coordinated manner. This process includes the remodeling of the spore envelopes to make Streptomyces spores resistant to detrimental environmental conditions. Sporulation septation and the synthesis of the thickened spore envelope in S. coelicolor A3(2) involves the Streptomyces spore wall synthesizing complex SSSC. The SSSC is a multi-protein complex including proteins directing peptidoglycan synthesis (MreBCD, PBP2, Sfr, RodZ) and cell wall glycopolymer synthesis (PdtA). It also includes two eukaryotic like serin/threonine protein kinases (eSTPK), PkaI and PkaH, which were shown to phosphorylate MreC. Since unbalancing phosphorylation activity by either deleting eSTPK genes or by expressing a second copy of an eSTPK gene affected proper sporulation, a model was developed, in which the activity of the SSSC is controlled by protein phosphorylation.

Live-cell imaging of Streptomyces conjugation.

Time-lapse imaging of conjugative plasmid transfer in Streptomyces revealed intriguing insights into the unique two-step conjugation process of this Gram+ mycelial soil bacterium. Differentially labelling of donor and recipient strains with distinct fluorescent proteins allowed the visualization of plasmid transfer in living mycelium. In nearly all observed matings, plasmid transfer occurred when donor and recipient hyphae made intimate contact at the lateral walls. Plasmid transfer does not involve a complete fusion of donor and recipient hyphae, but depends on a pore formed by the FtsK-like DNA translocase TraB. Following the initial transfer at the contact site of donor and recipient, the plasmids spread within the recipient mycelium by invading neighboring compartments, separated by cross walls. Intra-mycelial plasmid spreading depends on a septal cross wall localized multi-protein DNA translocation apparatus consisting of TraB and several Spd proteins and is abolished in a spd mutant. The ability to spread within the recipient mycelium is a crucial adaptation to the mycelial life style of Streptomyces, potentiating the efficiency of plasmid transfer.

Anatomical subgroup analysis of the MERIDIAN cohort: posterior fossa abnormalities.

OBJECTIVE: To assess the diagnostic and clinical contribution of fetal magnetic resonance imaging (MRI) in fetuses of the MERIDIAN cohort diagnosed with abnormalities of the posterior fossa as the only intracranial abnormality recognized on antenatal ultrasound. METHODS: This was a subgroup analysis of the MERIDIAN study of fetuses with abnormalities of the posterior fossa (with or without ventriculomegaly) diagnosed on antenatal ultrasound in women who had MRI within 2 weeks of ultrasound and for whom outcome reference data were available. The diagnostic accuracy of ultrasound and MRI is reported, as well as indicators of diagnostic confidence and effects on prognosis and clinical management. Appropriate diagnostic confidence was assessed by the score-based weighted average method, which combines diagnostic accuracy with diagnostic confidence data. RESULTS: Abnormalities confined to the posterior fossa according to ultrasound were found in 81 fetuses (67 with parenchymal and 14 with cerebrospinal fluid-containing lesions). The overall diagnostic accuracy for detecting an isolated posterior fossa abnormality was 65.4% for ultrasound and 87.7% for MRI (difference, 22.3% (95% CI, 14.0-30.5%); P < 0.0001). There was an improvement in 'appropriate' diagnostic confidence, as assessed by the score-based weighted average method (P < 0.0001), and a three-fold reduction in 'high confidence but incorrect diagnosis' was achieved using MRI. Prognostic information given to the women changed after MRI in 44% of cases, and the overall effect of MRI on clinical management was considered to be 'significant', 'major' or 'decisive' in 35% of cases. CONCLUSIONS: Our data suggest that any woman whose fetus has a posterior fossa abnormality as the only intracranial finding on ultrasound should have MRI for further evaluation. This is on the basis of improved diagnostic accuracy and confidence, which impacts substantially on the prognostic information given to women as well as their clinical management. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Anatomical subgroup analysis of the MERIDIAN cohort: failed commissuration.

OBJECTIVE: To assess the contribution of fetal magnetic resonance imaging (MRI) in fetuses of the MERIDIAN cohort diagnosed with either agenesis or hypogenesis of the corpus callosum (referred to collectively as failed commissuration) on antenatal ultrasound. METHODS: This was a subgroup analysis of the MERIDIAN study of fetuses with failed commissuration (with or without ventriculomegaly) diagnosed on ultrasound in women who had MRI assessment within 2 weeks of ultrasound and for whom outcome reference data were available. The diagnostic accuracy of ultrasound and MRI was studied, as well as indicators of diagnostic confidence and effects on prognosis/clinical management. Appropriate diagnostic confidence was assessed by the score-based weighted average method, which combines diagnostic accuracy with diagnostic confidence data. RESULTS: In the MERIDIAN cohort, 79 fetuses were diagnosed with failed commissuration on ultrasound (55 with agenesis and 24 with hypogenesis of the corpus callosum). The diagnostic accuracy for detecting failed commissuration was 34.2% for ultrasound and 94.9% for MRI (difference, 60.7% (95% CI, 47.6-73.9%), P < 0.0001). The diagnostic accuracy for detecting hypogenesis of the corpus callosum as a discrete entity was 8.3% for ultrasound and 87.5% for MRI, and for detecting agenesis of the corpus callosum as a distinct entity was 40.0% for ultrasound and 92.7% for MRI. There was a statistically significant improvement in 'appropriate' diagnostic confidence when using MRI as assessed by the score-based weighted average method (P < 0.0001). Prognostic information given to the women changed in 36/79 (45.6%) cases after MRI and its overall effect on clinical management was 'significant', 'major' or 'decisive' in 35/79 cases (44.3%). CONCLUSIONS: Our data suggest that any woman whose fetus has failed commissuration as the only intracranial finding detected on ultrasound should have MRI examination for further evaluation. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Anatomical subgroup analysis of the MERIDIAN cohort: ventriculomegaly.

OBJECTIVE: To assess the contribution of fetal magnetic resonance imaging (MRI) in fetuses of the MERIDIAN cohort diagnosed with ventriculomegaly (VM) as the only abnormal intracranial finding on antenatal ultrasound. METHODS: This was a subgroup analysis of the MERIDIAN study of fetuses with only VM diagnosed on ultrasound in women who had a subsequent MRI examination within 2 weeks and for whom outcome reference data were available. The diagnostic accuracy of ultrasound and MRI was reported in relation to the severity of VM. The difference in measurements of trigone size on the two imaging methods and the clinical impact of adding MRI to the diagnostic pathway were also studied. RESULTS: In 306 fetuses with VM, ultrasound failed to detect 31 additional brain abnormalities, having an overall diagnostic accuracy of 89.9% for ultrasound, whilst MRI correctly detected 27 of the additional brain abnormalities, having a diagnostic accuracy of 98.7% (P < 0.0001). There were other brain abnormalities in 14/244 fetuses with mild VM on ultrasound (diagnostic accuracy, 94.3%) and MRI correctly diagnosed 12 of these (diagnostic accuracy, 99.2%; P = 0.0005). There was a close agreement between the size of trigones measured on ultrasound and on MRI, with categorical differences in only 16% of cases, showing that MRI did not systematically overestimate or underestimate trigone size. Complete prognostic data were available in 295/306 fetuses and the prognosis category changed after MRI in 69/295 (23.4%) cases. The overall effect of MRI on clinical management was considered to be 'significant', 'major' or 'decisive' in 76/295 (25.8%) cases. CONCLUSION: Our data suggest that a woman carrying a fetus with VM as the only intracranial finding on ultrasound should be offered an adjuvant investigation by MRI for further evaluation. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Global Precipitation Measurement (GPM) Mission Products and Services at the NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC).

This article describes NASA/JAXA Global Precipitation Measurement (GPM) mission products and services at the NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC). Built on the success of the Tropical Rainfall Measuring Mission (TRMM), the next generation GPM mission consists of new precipitation measurement instruments and a constellation of international research and operational satellites to provide improved measurements of precipitation globally. To facilitate data access, research, applications, and scientific discovery, the GES DISC has developed a variety of data services for GPM. This article is intended to guide users in choosing GPM datasets and services at the GES DISC.

Advanced fiber tracking in early acquired brain injury causing cerebral palsy.

BACKGROUND AND PURPOSE: Diffusion-weighted MR imaging and fiber tractography can be used to investigate alterations in white matter tracts in patients with early acquired brain lesions and cerebral palsy. Most existing studies have used diffusion tensor tractography, which is limited in areas of complex fiber structures or pathologic processes. We explored a combined normalization and probabilistic fiber-tracking method for more realistic fiber tractography in this patient group. MATERIALS AND METHODS: This cross-sectional study included 17 children with unilateral cerebral palsy and 24 typically developing controls. DWI data were collected at 1.5T (45 directions, b=1000 s/mm(2)). Regions of interest were defined on a study-specific fractional anisotropy template and mapped onto subjects for fiber tracking. Probabilistic fiber tracking of the corticospinal tract and thalamic projections to the somatosensory cortex was performed by using constrained spherical deconvolution. Tracts were qualitatively assessed, and DTI parameters were extracted close to and distant from lesions and compared between groups. RESULTS: The corticospinal tract and thalamic projections to the somatosensory cortex were realistically reconstructed in both groups. Structural changes to tracts were seen in the cerebral palsy group and included splits, dislocations, compaction of the tracts, or failure to delineate the tract and were associated with underlying pathology seen on conventional MR imaging. Comparisons of DTI parameters indicated primary and secondary neurodegeneration along the corticospinal tract. Corticospinal tract and thalamic projections to the somatosensory cortex showed dissimilarities in both structural changes and DTI parameters. CONCLUSIONS: Our proposed method offers a sensitive means to explore alterations in WM tracts to further understand pathophysiologic changes following early acquired brain injury.

Diffusion MRI in corticofugal fibers correlates with hand function in unilateral cerebral palsy.

UNLABELLED: Diffusion MRI improves detection of abnormalities in white matter tracts in cerebral palsy (CP). Relationships between diffusion measurements and hand function are largely unexplored. We aimed first to assess microstructure of corticofugal fibers, and second to explore associations between tract injury as assessed by quantitative analysis of diffusion MRI and hand function in children with unilateral CP. METHODS: In this cross-sectional study, 15 children with unilateral CP (6 boys, median age 12.4 years, min 7.2, max 17) and 24 controls were included (9 boys, median age 12.7 years, min 8.8, max 17.3). Hand function was assessed with the Box and Blocks (B&B) test. Magnetic resonance diffusion data (b value = 1,000 s/mm(2), 45 directions) were collected on a 1.5-T scanner. Fractional anisotropy (FA), mean diffusivity (MD), and tensor eigenvalues were measured bilaterally in the cerebral peduncle (ROI1), the posterior limb of the internal capsule (PLIC, ROI2), and corticofugal fibers connecting these regions. RESULTS: In children with CP, FA in both ROIs and the partial tract corresponding to the affected hand was significantly lower compared to controls. This was caused by an increase in diffusivity perpendicular to the tract. After controlling for age, mean FA contralateral to the affected hand correlated with B&B scores, which was independent of lesion type or number of voxels in the partial tract, cerebral peduncle, or PLIC. CONCLUSIONS: FA in corticofugal fibers is a sensitive marker of damage to the motor system and correlates with hand function in CP. Using FA may improve early prediction of outcome.

Comparison of two different odorants in an olfactory detection threshold test of the Sniffin’ Sticks.

The olfactory test battery Sniffin' Sticks is a test of nasal chemosensory function that is based on pen-like devices for odour presentation. It consists of three olfactory subtests: threshold, discrimination, and identification. The detection threshold can be measured using two different odorants--n-butanol or PEA (phenylethyl alcohol). Both tasks are commonly applied in published studies, but little is known about the formal comparison of values obtained using them. Unlike the Sniffin' Sticks with n-butanol as odorant, there is poor validation for the threshold subtest with the odorant PEA. The purpose of this study was to compare these two different odorants. Both odorants were applied to 100 normosmic, healthy subjects (50 females). The experiment was divided into two sessions performed on two different days. After each threshold test the discrimination and identification subtests were conducted. We obtained significant differences in detection thresholds of PEA and n-butanol. The mean score of PEA threshold and PEA TDI (sum of threshold, discrimination, identification) was significantly higher compared to n-butanol. No significant correlation between individual PEA and n-butanol thresholds was observed. The differences between both odorants indicate that a formal validation of the Sniffin' Sticks with PEA as odorant for probing olfactory thresholds may be required.

Developmental changes in cerebral grey and white matter volume from infancy to adulthood.

In order to quantify human brain development in vivo, high resolution magnetic resonance images of 158 normal subjects from infancy to young adulthood were studied (age range 3 months-30 years, 71 males, 87 females). Data were analysed using algorithms based on voxel-based morphometry (VBM) (an objective whole brain processing technique) to generate global volume measures of whole brain, grey matter (GM) and white matter (GM). Gender-specific development of WM and GM volumes is characterised using a piecewise polynomial growth curve model to account for the non-linear nature of human brain development, implemented using Markov chain Monte Carlo simulation. The statistical method employed in this study proved to be successful and robust in the characterisation of brain development. The resulting growth curve parameter estimates lead to the following observations: total brain volume is demonstrated to undergo an initial rapid spurt. The total GM volume peaks during childhood and decreases thereafter, whereas total WM volume increases up to young adulthood. Relative to brain size, GM decreases and WM increases markedly over this age range in a non-linear manner, resulting in an increasing WM-to-GM ratio over much of the observed age range. In addition, significant gender differences are found. In general, brain volume and total white and grey matter volume are larger in males than in females, with a time-dependent difference over the age range studied. Over part of the observed age range females tend to have more GM volume relative to brain size and lower WM-to-GM ratio than males. The presented findings should be taken into account when investigating physiological and pathological changes during brain development.

Chemosensory properties of human sweat.

Human sweat contains a mixture of odorants with trigeminal as well as olfactory properties. It has been shown that trigeminal perception is necessary to localize odors and that humans are not able to localize substances that only activate the olfactory system. To analyze the chemosensory properties of human sweat, we studied humans' ability to localize sweat stimuli to the different nostrils. Human sweat was collected during a bicycle workout (20 males) and was then applied to 34 different subjects (17 females) during odor detection and localization experiments by using an olfactometer. During the detection experiment, subjects were instructed to discriminate between sweat stimuli (20) and blanks (10). During the localization experiment, they were assigned to allocate the stimuli to either the right (15) or the left nostril (15). We found that subjects were able to detect the sweat stimuli with moderate to high sensitivity. However, they failed to localize the sweat stimuli to the accurate nostril above chance level. Due to this inability to localize the stimuli, we conclude that human sweat does not activate the intranasal trigeminal system but only the olfactory system.

Hydrops fetalis in three male fetuses of a female with incontinentia pigmenti.

OBJECTIVES: Careful investigation of hydrops fetalis (HF) is important with regard to genetic counselling and prenatal diagnosis. HF is known to be associated with various genetic disorders. To date there has been only one report of a male fetus in whom incontinentia pigmenti (IP) was associated with generalised oedema. We describe a family who had a girl with clinical signs of IP after three consecutive miscarriages of three male fetuses due to HF. RESULTS: Molecular genetic analysis showed a mutation in the NEMO/IKK(chi) gene in the girl and the mother, which confirmed the diagnosis of IP in both cases. In the two fetuses that could be investigated, inheritance of the affected maternal X chromosome could be demonstrated retrospectively by linkage analysis. CONCLUSION: The present findings suggest that IP might be an X-linked dominant trait causing HF in male fetuses. In cases of recurrent HF in male fetuses, minimal signs of IP in the maternal line should therefore be carefully investigated in order to be able to perform mutational analysis and to offer appropriate genetic counselling.

The clinical phenotype of succinic semialdehyde dehydrogenase deficiency (4-hydroxybutyric aciduria): case reports of 23 new patients.

OBJECTIVES: To further define the clinical spectrum of the disease for pediatric and metabolic specialists, and to suggest that the general pediatrician and pediatric neurologist consider succinic semialdehyde dehydrogenase (SSADH) deficiency in the differential diagnosis of patients with (idiopathic) mental retardation and emphasize the need for accurate, quantitative organic acid analysis in such patients. PATIENTS: The clinical features of 23 patients (20 families) with SSADH deficiency (4-hydroxybutyric acid-uria) are presented. The age at diagnosis ranged from 3 months to 25 years in the 11 male and 12 female patients; consanguinity was noted in 39% of families. OUTCOME MEASUREMENTS: The following abnormalities were observed (frequency in 23 patients): motor delay, including fine-motor skills, 78%; language delay, 78%; hypotonia, 74%; mental delay, 74%; seizures, 48%; decreased or absent reflexes, 39%; ataxia, 30%; behavioral problems, 30%; hyperkinesis, 30%; neonatal problems, 26%; and electroencephalographic abnormalities, 26%. Associated findings included psychoses, cranial magnetic resonance or computed tomographic abnormalities, and ocular problems in 22% or less of patients. Therapy with vigabatrin proved beneficial to varying degrees in 35% of the patients. Normal early development was noted in 30% of patients. CONCLUSIONS: Our data imply that two groups of patients with SSADH deficiency exist, differentiated by the course of early development. Our recommendation would be that accurate, quantitative organic acid analysis in an appropriate specialist laboratory be requested for any patients presenting with two or more features of mental, motor, or language delay and hypotonia of unknown cause. Such analyses are the only definitive way to diagnose SSADH deficiency; the diagnosis can be confirmed by determination of enzyme activity in white cells from whole blood. We think that increased use of organic acid determination will lead to increased diagnosis of SSADH deficiency and a more accurate representation of disease frequency. As additional patients are identified, we should have a better understanding of both the metabolic and clinical profiles of SSADH deficiency.

[Perinatally-induced hypoxic-ischemic encephalopathy? Possibilities of retrospective evaluation from the neuropediatric viewpoint]. / Perinatal verursachte hypoxisch-ischämische Enzephalopathie? Möglichkeiten der retrospektiven Beurteilung aus neuropädiatrischer Sicht.

This paper analyzes the feasibility of determining retrospectively, from a neuropediatric standpoint, whether an existing neurological disorder can be traced back to a perinatal hypoxic-ischemic encephalopathy. In principal, we can assume that there is a correlation between this time and pathogenesis of the brain injury on the one hand and the neurological symptoms on the other if these conditions are fulfilled 1. In the first days of live term infants revealed cerebral symptoms (like abnormality of muscle tone and consciousness and seizures) which manifest themselves in a typical sequence and are combined with involvement of other organ systems. In pre-term infants the clinical signs are often not clearly definable. 2. The subsequent neurological disorder after the primary symptoms must be a spastic-less commonly in term infants a dyskinetic one. 3. Lesions typical for the child's gestational age are visible on magnetic resonance imaging.

Enzymatic and immunologic identification of succinic semialdehyde dehydrogenase in rat and human neural and nonneural tissues.

We have identified succinic semialdehyde dehydrogenase protein in rat and human neural and nonneural tissues. Tissue localization was determined by enzymatic assay and by western immunoblotting using polyclonal antibodies raised in rabbit against the purified rat brain protein. Although brain shows the highest level of succinic semialdehyde dehydrogenase activity, substantial amounts of enzyme activity occur in mammalian liver, pituitary, heart, and ovary. We further demonstrate the absence of succinic semialdehyde dehydrogenase enzyme activity and protein in brain, liver, and kidney tissue samples from an individual affected with succinic semialdehyde dehydrogenase deficiency, thereby verifying the specificity of our antibodies.

Bilateral spastic cerebral palsy--MRI pathology and origin. Analysis from a representative series of 56 cases.

MRI of the brain was performed on 56 children with bilateral spastic cerebral palsy (CP) at a mean age of 10.7 years. Specific pathology was found in 91 per cent; periventricular leukomalacia was present in 42 per cent of term- and 87 per cent of preterm-born children. Parasagittal subcorticocortical injury, multicystic encephalomalacia and basal ganglia lesions were identified in 16 per cent, in all but one associated with severe peri-/neonatal events at term or near term. Maldevelopment comprised 9 per cent, all but one found in term-born children. MRI morphology correlated strikingly with outcome. Periventricular leukomalacia was associated with more severe disability in term- than preterm-born children.

Pre- and postnatal diagnosis of succinic semialdehyde dehydrogenase deficiency using enzyme and metabolite assays.

We report our cumulative experience for the prenatal diagnosis of succinic semialdehyde dehydrogenase (SSADH) deficiency in seven 'at-risk' pregnancies from four unrelated families. Prenatal diagnosis was performed by determination of 4-hydroxybutyric acid (4-HBA) concentration in amniotic fluid using isotope-dilution gas chromatography-mass spectrometry in conjunction with assay of SSADH activity in biopsied chorionic villus and/or cultured amniocytes. In three of four pregnancies predicted as affected, confirmation was obtained by demonstration of deficient SSADH activity in fetal tissues. Our results suggest that determination of 4-HBA concentration in amniotic fluid combined with enzyme determination in cultured or biopsied tissue represents a reliable method for the prenatal diagnosis of SSADH deficiency.,

[Laser thermal venous obliteration: experimental results in the rat model]. / Laserthermische Venenobliteration: experimentelle Ergebnisse am Rattenmodell.

In an animal study, thermal laser application was tested for inducing venous thrombosis. In 54 rats, metal-tipped laser catheters ("hot tip") were trans-jugularly inserted into the distal inferior caval vein which was thermally damaged by laser pulses of 4-7 W. Suitable energy levels were defined in an acute experiment in 25 rats. Chronic experiment with 29 rats included survival time of two weeks after laser application, autopsy and histological work-up of the caval vein. In 27 rats, laser application was successfully performed and induced thrombosis in 17 animals. Perforation of the caval vein occurred in 10 rats. Thermal laser application is capable of inducing venous thrombosis. The power ranges inducing thrombosis or thermal perforation are, however, too narrow to allow safe clinical application of this technique.