Large-scale analysis of structural brain asymmetries during neurodevelopment: Associations with age and sex in 4265 children and adolescents.

Only a small number of studies have assessed structural differences between the two hemispheres during childhood and adolescence. However, the existing findings lack consistency or are restricted to a particular brain region, a specific brain feature, or a relatively narrow age range. Here, we investigated associations between brain asymmetry and age as well as sex in one of the largest pediatric samples to date (n = 4265), aged 1-18 years, scanned at 69 sites participating in the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) consortium. Our study revealed that significant brain asymmetries already exist in childhood, but their magnitude and direction depend on the brain region examined and the morphometric measurement used (cortical volume or thickness, regional surface area, or subcortical volume). With respect to effects of age, some asymmetries became weaker over time while others became stronger; sometimes they even reversed direction. With respect to sex differences, the total number of regions exhibiting significant asymmetries was larger in females than in males, while the total number of measurements indicating significant asymmetries was larger in males (as we obtained more than one measurement per cortical region). The magnitude of the significant asymmetries was also greater in males. However, effect sizes for both age effects and sex differences were small. Taken together, these findings suggest that cerebral asymmetries are an inherent organizational pattern of the brain that manifests early in life. Overall, brain asymmetry appears to be relatively stable throughout childhood and adolescence, with some differential effects in males and females.

Characterizing the metabolomic signature of attention-deficit hyperactivity disorder in twins.

Emerging evidence implicate the gut microbiota as a potential susceptibility factor in attention-deficit hyperactivity disorder (ADHD), a common multifactorial neurodevelopmental condition. However, little is known about the biochemical signature of ADHD, including the metabolic contribution of the microbiota via the gut-brain axis, and the relative contribution of genetics and environmental factors. Here, we perform unbiased metabolomic profiling of urine and fecal samples collected from a well-characterized Swedish twin cohort enriched for ADHD (33 ADHD, 79 non-ADHD), using 1H nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry. Our results highlight sex-specific patterns in the metabolic phenotype of individuals with ADHD. Specifically, the urine profile of males, but not females, with ADHD was characterized by greater excretion of hippurate, a product of microbial-host co-metabolism that can cross the blood-brain-barrier with bioactivity of potential relevance to ADHD. This trans-genomic metabolite was also negatively correlated with IQ in males and was significantly correlated with fecal metabolites associated with gut microbial metabolism. The fecal profile of ADHD individuals was characterized by increased excretion of stearoyl-linoleoyl-glycerol, 3,7-dimethylurate, and FAD and lower amounts of glycerol 3-phosphate, thymine, 2(1H)-quinolinone, aspartate, xanthine, hypoxanthine, and orotate. These changes were independent of ADHD medication, age, and BMI. Furthermore, our specific twins' models revealed that many of these gut metabolites had a stronger genetic influence than environmental. These findings suggest that metabolic disturbances in ADHD, involving combined gut microbial and host metabolic processes, may largely derive from gene variants previously linked to behavioral symptoms in this disorder. This article is part of the Special Issue on "Microbiome & the Brain: Mechanisms & Maladies".

Global and local visual processing in autism - a co-twin-control study.

BACKGROUND: Autism Spectrum Disorder (ASD) is associated with altered global and local visual processing. However, the nature of these alterations remains controversial, with contradictory findings and notions ranging from a reduced drive to integrate information into a coherent 'gestalt' ("weak central coherence" = WCC) to an enhanced perceptual functioning (EPF) in local processing. METHODS: This study assessed the association between autism and global/local visual processing, using a large sample of monozygotic (MZ) and dizygotic (DZ) twins (N = 290, 48% females, age = 8-31 years). The Fragmented Pictures Test (FPT) assessed global processing, whereas local processing was estimated with the Embedded Figures Test (EFT) and the Block Design Test (BDT). Autism was assessed both categorically (clinical diagnosis), and dimensionally (autistic traits). Associations between visual tasks and autism were estimated both across the cohort and within-twin pairs where all factors shared between twins are implicitly controlled. RESULTS: Clinical diagnosis and autistic traits predicted a need for more visual information for gestalt processing in the FPT across the cohort. For clinical diagnosis, this association remained within-pairs and at trend-level even within MZ twin pairs alone. ASD and higher autistic traits predicted lower EFT and BDT performance across the cohort, but these associations were lost within-pairs. CONCLUSIONS: In line with the WCC account, our findings indicate an association between autism and reduced global visual processing in children, adolescents and young adults (but no evidence for EPF). Observing a similar association within MZ twins suggests a non-shared environmental contribution.

Social Cognition in Autism and Other Neurodevelopmental Disorders: A Co-twin Control Study.

Alterations in social cognition (SC) are hypothesized to underlie social communication and interaction challenges in autism spectrum disorder (ASD). The aetiological underpinnings driving this association remain unclear. We examined SC in 196 twins with ASD, other neurodevelopmental disorders or typical development using the naturalistic Movie for the Assessment of Social Cognition. Autism and its severity were assessed with the Autism Diagnostic Observation Schedule-2, and autistic traits with the Social Responsiveness Scale-2. Using within twin-pair regression models, controlling for age, sex, IQ, and unmeasured familial confounders such as genetic background and shared-environment, SC correlated with ASD diagnosis, autism severity, and autistic traits. Our findings highlight the importance of SC alterations in autism and suggest a non-shared environmental impact on the association.

Chlamydia trachomatis genotypes A and B from urogenital specimens of patients in Spain: molecular characterization.

OBJECTIVES: Chlamydia trachomatis ompA genotypes A and B, primarily associated with trachoma, were unexpectedly detected in urogenital samples of patients in Spain, a trachoma-free country. In this study, we aimed to explain this finding using analysis of organotropism-related genes and a multilocus sequence typing (MLST) technique. METHODS: C. trachomatis genotypes A or B were detected in 8/930 (0.9%) infection episodes between 2006 and 2012. In these strains, organotropism-related genes (polymorphic membrane protein gene H, tryptophan synthase gene A, CTA0934, and cytotoxin) were studied. Further, the strains were analysed by MLST, using a polymerase chain reaction that amplifies five highly variable genomic loci (hctB, CT058, CT144, CT172, and pbpB). Amplicons were sequenced and phylogenetic analysis was conducted. RESULTS: Seven strains were detected in the eight infection episodes (in one patient, an identical strain being found in two episodes). Analysis of organotropism-related genes showed that these strains shared genetic features characteristic of genitotropic genotypes but not of trachoma strains. Three strains of genotype A showed a unique and new MLST-sequence type (ST551, allele profile 8-8-2-27-69). The four strains of genotype B belonged to ST138. CONCLUSIONS: C. trachomatis ompA genotypes A and B associated with trachoma, but detected sporadically in urogenital samples in trachoma-free countries, may be the result of recombination between strains adapted to trachoma and strains adapted to sexual transmission.

The danger of being inattentive - ADHD symptoms and risky sexual behaviour in Russian adolescents.

BACKGROUND: Prior research has indicated that attention-deficit/hyperactivity disorder (ADHD) symptoms may be associated with an increased likelihood of engaging in risky sexual behaviour (RSB). However, research on this association among adolescents has been comparatively limited and mainly confined to North America. The aim of this study was to examine if inattention and hyperactivity/impulsivity symptoms were linked to RSB in a community cohort sample of Russian adolescents. METHODS: The study was based on a group of 537 adolescents from Northern Russia. Information on inattention and hyperactivity/impulsivity as well as conduct problems was obtained through teacher ratings, while information on RSB (previous unprotected sex, number of sexual partners, sex while intoxicated and partner pregnancies), substance use, perception of risk, and parenting behaviour was based on students' self-reports. Binary logistic regression analysis was used to examine associations between the variables. RESULTS: Teacher-rated inattention symptoms predicted RSB, independently of co-morbid conduct problems, substance use, risk perception, and different parenting styles (parental warmth, involvement and control). In addition, male sex, binge drinking and a lower assessment of perceived risk were all significantly associated with RSB in an adjusted model. Neither teacher-rated hyperactivity/impulsivity symptoms nor conduct problems were linked to RSB in the full model. CONCLUSIONS: Deficits in planning and organizing behaviours, being easily distracted and forgetful seem to be of importance for RSB in Russian adolescents. This highlights the importance of discriminating between different ADHD symptoms in adolescence to prevent risk behaviours and their potentially detrimental outcomes on health and well-being.

High maternal cortisol levels during pregnancy are associated with more psychiatric symptoms in offspring at age of nine - A prospective study from Nicaragua.

Maternal exposure to stress or adversity during pregnancy has been associated with negative health effects for the offspring including psychiatric symptoms. Programming of the hypothalamic-pituitary-adrenal (HPA) axis has been suggested as one mediating process. In order to investigate possible long term effects of stressors during pregnancy, we followed 70 children and their mothers from pregnancy up to nine years aiming to investigate if maternal cortisol levels and distress/exposure to partner violence were associated with child psychiatric symptoms and child cortisol levels at follow-up. Maternal distress was evaluated using The Self Reporting Questionnaire, exposure to partner violence by an instrument from WHO and child psychiatric symptoms with Child Behavior Checklist (CBCL). We adjusted the analyses for gestational week, gender, SES, perinatal data and maternal distress/exposure to partner violence at child age of nine years. Elevated maternal cortisol levels during pregnancy, as a possible marker of maternal stress load, were correlated with higher CBCL-ratings, especially concerning externalizing symptoms. Maternal cortisol levels during pregnancy were not associated with child cortisol levels at child age of nine years. Maternal distress and exposure to partner violence during pregnancy were neither associated with child psychiatric symptoms nor child cortisol levels. To conclude, intrauterine exposure to elevated cortisol levels was associated with higher ratings on offspring psychopathology at nine years of age. The lack of association between maternal cortisol levels during pregnancy and child cortisol levels does not support the hypothesis of fetal programming of the HPA-axis, but reliability problems may have contributed to this negative finding.

The Pressure-Activation-Stress scale in relation to ADHD and cortisol.

The Pressure-Activation-Stress (PAS) scale is a self-report questionnaire for children concerning perceived stress. To explore behavioral and physiological correlates, we investigated if scores discriminate between a group prone to perceive high levels of stress [children with attention-deficit/hyperactivity disorder (ADHD)] and a healthy school sample, and if they are associated with diurnal cortisol levels. The PAS scale was filled in at home by children (11-17 years) with clinically confirmed ADHD (n = 102) and non-affected comparisons (n = 146). Saliva samples were collected four times during a regular school day for radioimmunoassay analysis of cortisol. Subtypes and severity of ADHD symptoms were determined using parental rating scales. Children with ADHD scored higher on the PAS scale than a school sample. The PAS scores were similar over ages in the ADHD group while they increased with age in the healthy group. Female sex was associated with higher stress in both groups but no gender interaction was found. No association was found between PAS scores and cortisol levels in neither group. Children in the ADHD group had a lower ratio of cortisol levels/perceived stress on all sampling occasions, built up both by the higher PAS scores and the lower cortisol levels in children with ADHD. The higher PAS scores in children with ADHD support the validity of the scale. The lack of association between PAS scores and diurnal cortisol levels is intriguing and illustrates the complexity of the stress concept. Stress-related fragility seems to accompany ADHD during childhood.

Long-term follow-up and cost analysis following surgery for small bowel obstruction caused by intra-abdominal adhesions.

BACKGROUND: This study examined the natural course of patients following surgery for small bowel obstruction (SBO) caused by abdominal adhesions. In addition, a cost analysis was performed. METHODS: A retrospective analysis was undertaken of 102 patients who underwent surgery between 1987 and 1992 for intestinal obstruction due to abdominal adhesions. RESULTS: Median follow-up was 14 years. The 102 patients experienced 273 episodes of intestinal obstruction after the index operation, of which 237 involved inpatient readmissions; 47.3 per cent of the episodes resulted in further surgery. Single band adhesions were more common in patients with no previous abdominal surgery (P < 0.001). Some 52.0 per cent of the patients had undergone only one operation for SBO. A mean of 2.7 episodes per patient occurred after the index operation. The cost of adhesion-related problems in this study was 1,588,594 euros or 6702 euros per inpatient episode. CONCLUSION: The readmission rate in a selected cohort of patients with proven intra-abdominal adhesions was higher than reported previously. The annual cost of adhesion-related problems in Sweden was estimated as 39.9-59.5 million euros, and the cost of inpatient readmissions was almost equal to that for gastric cancer.

Oxetane locked thymidine in the Dickerson-Drew dodecamer causes local base pairing distortions -- an NMR structure and hydration study.

The introduction of a North-type sugar conformation constrained oxetane T block, 1-(1',3'-O-anhydro-beta-D-psicofuranosyl) thymine, at the T(7) position of the self-complementary Dickerson-Drew dodecamer, d[(5'-C(1)G(2)C(3)G(4)A(5)A(6)T(7)T(8)C(9)G(10)C(11)G(12)-3')](2), considerably perturbs the conformation of the four central base pairs, reducing the stability of the structure. UV spectroscopy and 1D NMR display a drop in melting temperature of approximately 10 degrees C per modification for the T(7) oxetane modified duplex, where the T(7) block has been introduced in both strands, compared to the native Dickerson-Drew dodecamer. The three dimensional structure has been determined by NMR spectroscopy and has subsequently been compared with the results of 2.4 ns MD simulations of the native and the T(7) oxetane modified duplexes. The modified T(7) residue is found to maintain its constrained sugar- and the related glycosyl torsion conformations in the duplex, resulting in staggered and stretched T(7).A(6) and A(6).T(7) non-linear base pairs. The stacking is less perturbed, but there is an increased roll between the two central residues compared to the native counterpart, which is compensated by tilts of the neighboring base steps. The one dimensional melting profile of base protons of the T(7) and T(8) residues reveals that the introduction of the North-type sugar constrained thymine destabilizes the core of the modified duplex, promoting melting to start simultaneously from the center as well as from the ends. Temperature dependent hydration studies by NMR demonstrate that the central T(7).A(6)/A(6).T(7) base pairs of the T(7) oxetane modified Dickerson-Drew dodecamer have at least one order of magnitude higher water exchange rates (correlated to the opening rate of the base pair) than the corresponding base pairs in the native duplex.

A uniform mechanism correlating dangling-end stabilization and stacking geometry.

The geometry of the dangling base in 105 published structures (from X-ray/NMR) containing single-stranded overhangs has been analyzed and correlated to the thermodynamic stabilization found (UV) for the corresponding dangling base/closing basepair combination in short oligonucleotides. The study considers most combinations of closing basepairs, sequence and dangling base residue type, attached in both the 3'- and 5'-ends of both DNA and RNA. Linear regression analysis showed a straightforward correlation (R = 0.873) between the degree of screening for the hydrogen bonds of the closing basepair provided by the dangling base and the resulting thermodynamic stabilization in both DNA and RNA series with dangling ends either at the 3'- or at the 5'-terminus. Regression analysis of only the datasets from RNA gives an improved correlation, R = 0.934, showing that dangling ends on RNA are more ordered than the dangling ends on DNA, R = 0.376. This study highlights the gain in the free energy of stabilization owing to the favorable stacking between the dangling nucleobase and the neighboring basepair and the resulting strengthening of the hydrogen bond of the closing basepair. By acting as a hydrophobic cap on the terminal of the DNA or RNA duplex, the dangling-end residue restricts the bulk water access to the terminal basepair, thereby providing it with a microenvironment devoid of water, which consequently enhances its thermodynamic stability, making it energetically comparable to the corresponding internal basepair. Thus, one single structural model consisting of the interplay of the above electrostatic interactions can be used to explain the molecular basis of the observed thermodynamic effects for dangling-end attachment to the 3'- and 5'-ends of both DNA and RNA duplexes, which is a key step toward accurate dangling-end effect prediction.

Improved functional outcome after spinal cord injury in iNOS-deficient mice.

STUDY DESIGN: Functional outcome was evaluated following experimental compression-type spinal cord injury (SCI) in wild-type mice and knockout mice, lacking the inducible nitric oxide synthase (iNOS) gene. OBJECTIVES: To evaluate the role of the nitric oxide generating enzyme iNOS in SCI. METHODS: The experimental animals were subjected to an extradural compression of the thoracic spinal cord. Functional outcome was studied during the first 2 weeks post-injury using a scoring system for assessment of hind limb motor function. RESULTS: Injury resulted in initial paraplegia followed by gradual improvement of motor function in most cases. Mice lacking the iNOS gene (iNOS-/-) clearly tended to have a better functional outcome than wild-type mice. The difference was significant on day 14 after injury. CONCLUSION: In accordance with a few earlier experimental studies, showing beneficial effects of pharmacological iNOS inhibition, the present report would indicate a destructive influence of iNOS following spinal cord trauma.

Single-stranded adenine-rich DNA and RNA retain structural characteristics of their respective double-stranded conformations and show directional differences in stacking pattern.

The structural preorganization of isosequential ssDNA and ssRNA hexamers d/r(GAAAAC)(1) [J. Am. Chem. Soc. 2003, 125, 9948] have been investigated by NMR and molecular dynamics simulations. Analysis of the nuclear Overhauser effect spectrometry (NOESY) footprints in the aqueous solution has shown that there is a substantial population of ordered right-handed helical structure in both hexameric single-stranded DNA and RNA, which are reminiscent of their respective right-handed helical duplex form, despite the fact these single-stranded molecules are devoid of any intermolecular hydrogen bonds. The NMR-constrained molecular dynamics (1.5 ns) derived geometries of the adenine-adenine overlaps at each dinucleotide step of the hexameric ssDNA (1a) and ssRNA (1b) show that the relatively electron-rich imidazole stacks above the electron-deficient pyrimidine in 5' to 3' direction in ssDNA (1a) while, in contradistinction, the pyrimidine stacks above the imidazole in the 5' to 3' direction in ssRNA (1b). This also means that the pi-frame of the 5'-pyrimidine can interact with the relatively positively charged imino and amino protons in the 3' direction in ssRNA and in the 5' direction in ssDNA, thereby stabilizing the twist and slide observed in the stacked oligonucleotides. The differently preferred stacking geometries in ssDNA and ssRNA have direct physicochemical implications for self-assembly and pK(a) modulation by the nearest-neighbor interactions, as well as for the dangling-end stabilization effects and imino-proton reactivity.

Cognitive and histopathological outcome after weight-drop brain injury in the rat: influence of systemic administration of monoclonal antibodies to ICAM-1.

The aim of this study was to evaluate whether treatment with the anti-ICAM-1 antibody 1A29 influences functional or histopathological outcome following severe controlled cortical contusion in rats. The spatial learning deficits were studied using Morris water maze (MWM) paradigm in which the animals were given four daily acquisition trials for four consecutive days, starting on day 10 post-injury. Both 1A29-treated (n=8) and vehicle-treated (n=8) traumatized animals needed longer time than sham-operated rats (n=8) to find the hidden escape platform on days 11, 12 and 13. Compared to shams, significantly increased escape latency was noted on day 12 in vehicle-treated group and on days 12 and 13 in 1A29-treated animals. MWM performance did not differ significantly between the two trauma groups. Histopathological evaluation of the injured brains 15 days after trauma revealed ipsilateral cortical cavitation as well as ipsilateral hippocampal and thalamic lesions. MAP2 immunostaining showed a nonsignificant tendency towards more pronounced hippocampal injury in the 1A29-treated animals. Image analysis of glial fibrillary acidic protein- and ionized calcium binding adapter molecule 1-immunostained sections revealed astrocytic activation in the ipsilateral thalamus and microglial activation in both ipsilateral thalamus and hippocampus of traumatized animals, but no significant differences between the trauma groups. In summary, this study shows that spatial memory deficits occur following a weight-drop injury to the rat brain. Treatment with the anti-ICAM-1 antibody 1A29 did not significantly change the recorded functional or histopathological measures of outcome.

Do the 16 mer, 5'-GUGGUCUGAUGAGGCC-3' and the 25 mer, 5'-GGCCGAAACUCGUAAGAGUCACCAC-3', form a hammerhead ribozyme structure in physiological conditions? An NMR and UV thermodynamic study.

In a wide range of salt concentrations, 10-30 mM phosphate buffer containing up to 0.5 M Li2SO4 and 300 mM NaCl, 7.5 mM Mg2+, pH 5.5-7.5, a mixture of the 16 mer and the 25 mer RNA strands does not form a hammerhead in any amount detectable by NMR at 600 MHz. The imino-, amino-, aromatic- and anomeric protons in the NMR spectra of both the 16 mer and the 25 mer RNA have been assigned separately. Both the 16 mer and the 25 mer RNA both take up very stable hairpin structures, and when mixed together there is no major change of conformation in neither oligo-RNA.

White matter preservation after spinal cord injury in ICAM-1/P-selectin-deficient mice.

We have previously demonstrated that mice deficient in ICAM-1 and P-selectin (ICAM-1/PS-/-) have improved functional recovery after spinal cord injury (SCI), compared to injured controls. In this study the spinal cords from wild-type and ICAM-1/PS-/- mice were evaluated histopathologically 14 days after severe compression-type SCI. Following injury there was an atrophy of the spinal cord. Significant sparing of total cross-sectional area was noted in ICAM-1/PS-/- mice compared to injured controls at the site of compression and in the distal peri-injury zone. Likewise, significant preservation of white matter area, as measured by Luxol staining, was found in mutant mice at the site of injury and in the proximal peri-injury zone. Gray matter damage was investigated by microtubule-associated protein 2 immunohistochemistry. Following severe SCI, a trend of gray matter sparing was noticed in ICAM-1/PS-/- animals. Quantitation of iba1 immunohistochemistry revealed that microglial reaction was significantly suppressed in the mutant animals. Astroglial reaction, visualized by GFAP immunostaining, did not differ between groups. Our results indicate that ICAM-1 and P-selectin are involved in autodestructive events provoked by the initial injury but the precise underlying mechanisms remain obscure.

The first example of a Hoogsteen base-paired DNA duplex in dynamic equilibrium with a Watson-Crick base-paired duplex--a structural (NMR), kinetic and thermodynamic study.

A single-point substitution of the O4' oxygen by a CH2 group at the sugar residue of A6 (i.e. 2'-deoxyaristeromycin moiety) in a self-complementary DNA duplex, 5'-d(C1G2C3G4A5A6T7T8C9G10C11G12)2(-3), has been shown to steer the fully Watson-Crick basepaired DNA duplex (1A), akin to the native counterpart, to a doubly A6:T7 Hoogsteen basepaired (1B) B-type DNA duplex, resulting in a dynamic equilibrium of (1A)<==>(1B): Keq = k1/k(-1) = 0.56+/-0.08. The dynamic conversion of the fully Watson-Crick basepaired (1A) to the partly Hoogsteen basepaired (1B) structure is marginally kinetically and thermodynamically disfavoured [k1 (298K) = 3.9 0.8 sec(-1); deltaHdegrees++ = 164+/-14 kJ/mol; -TdeltaS degrees++ (298K) = -92 kJ/mol giving a deltaG degrees++ 298 of 72 kJ/mol. Ea (k1) = 167 14 kJ/mol] compared to the reverse conversion of the Hoogsteen (1B) to the Watson-Crick (1A) structure [k-1 (298K) = 7.0 0.6 sec-1, deltaH degrees++ = 153 13 kJ/mol; -TdeltaSdegrees++ (298K) = -82 kJ/mol giving a deltaGdegrees++(298) of 71 kJ/mol. Ea (k-1) = 155 13 kJ/mol]. Acomparison of deltaGdegrees++(298) of the forward (k1) and backward (k-1) conversions, (1A)<==>(1B), shows that there is ca 1 kJ/mol preference for the Watson-Crick (1A) over the double Hoogsteen basepaired (1B) DNA duplex, thus giving an equilibrium ratio of almost 2:1 in favour of the fully Watson-Crick basepaired duplex. The chemical environments of the two interconverting DNA duplexes are very different as evident from their widely separated sets of chemical shifts connected by temperature-dependent exchange peaks in the NOESY and ROESY spectra. The fully Watson-Crick basepaired structure (1A) is based on a total of 127 intra, 97 inter and 17 cross-strand distance constraints per strand, whereas the double A6:T7 Hoogsteen basepaired (1B) structure is based on 114 intra, 92 inter and 15 cross-strand distance constraints, giving an average of 22 and 20 NOE distance constraints per residue and strand, respectively. In addition, 55 NMR-derived backbone dihedral constraints per strand were used for both structures. The main effect of the Hoogsteen basepairs in (1B) on the overall structure is a narrowing of the minor groove and a corresponding widening of the major groove. The Hoogsteen basepairing at the central A6:T7 basepairs in (1B) has enforced a syn conformation on the glycosyl torsion of the 2'-deoxyaristeromycin moiety, A6, as a result of substitution of the endocyclic 4'-oxygen in the natural sugar with a methylene group in A6. A comparison of the Watson-Crick basepaired duplex (1A) to the Hoogsteen basepaired duplex (1B) shows that only a few changes, mainly in alpha, sigma and gamma torsions, in the sugar-phosphate backbone seem to be necessary to accommodate the Hoogsteen basepair.

Improved recovery after spinal cord injury in neuronal nitric oxide synthase-deficient mice but not in TNF-alpha-deficient mice.

Wild-type mice and mice lacking nitric oxide synthase (NOS) of neuronal type or TNF-alpha were subjected to an extradural compression of the thoracic spinal cord. The functional outcome of the hind limbs was assessed by using a motor function score (MFS). The injury resulted in paraplegia of the hind limbs in wild-type mice at day 1 after injury. Gradual recovery was observed during the following 14 days. Injured NOS -/- animals had an improved hind limb motor function during the entire observation period compared to wild-type controls. The difference was statistically significant on day 10 (p < 0.022) and day 14 (p < 0.048) after injury. At the site of injury, there was a trend of gray matter preservation in NOS -/- mice, as measured by MAP2 staining (p < 0.077). Injured mice lacking TNF-alpha had the lowest motor score among all the groups on day 1. During the following period, they had motor scores similar to those of wild-type controls and there was no significant difference at any time point. TNF-alpha -/- animals showed a trend of decreased white matter preservation compared to wild-type animals (p < 0.097). Our study shows that after spinal cord injury, mice lacking NOS have a better functional ability of their hind limbs than controls with the same degree of injury. This would indicate that the functional outcome is influenced in a negative way in wild mice by the presence of NO. The degree of secondary damage to the spinal cord might be attenuated in NOS-deficient mice.

Spinal cord injury in ICAM-1-deficient mice: assessment of functional and histopathological outcome.

Adhesion molecule-mediated adhesion and extravasation of leukocytes may constitute a mechanism of secondary tissue damage following spinal cord injury (SCI). The objective of the present study was to determine to what extent genetic deficiency in the adhesion molecule ICAM-1 influences functional and histopathological measures of outcome following SCI. ICAM-1-/- (n = 11) and wild-type (n = 9) mice were subjected to a compression-type SCI. Assessment of hind-limb motor function was done on days 1, 2, 4, 7, 10, and 14 after injury, using a motor function scoring system. Injury resulted in a drastically impaired hind limb motor function at day one after injury followed by a partial recovery during the observation period. No significant functional differences were found between the experimental groups at any time-point. Fourteen days after injury the animals were sacrificed and the spinal cords were processed for histopathological and immunohistochemical evaluation. Luxol-stained, MAP2-, GFAP- and iba-1-immunostained cross-sectional areas were quantitated using a computerized image analysis system to investigate white matter damage, neuronal loss, astrocytic response and microglial activation respectively. None of these parameters differed significantly between the groups. Separate experiments revealed that the early (24 h postinjury) infiltration of polymorphonuclear leukocytes was significantly reduced in white matter but not in the grey matter of ICAM-1-/- mice, compared to injured controls. In summary, these results do not support the concept that ICAM-1 alone mediates secondary tissue damage following traumatic SCI in the mouse.