Treatment and outcome of the severely head injured child

Twenty-four children (aged 3 months to 14 years) with severe head injuries were treated by means of invasive neurointensive care for normalizing intracranial pressure (ICP) involving hyperventilation, control of body temperature, dexamethasone, barbiturates and continuous intracranial and arterial pressure monitoring. The Glasgow Coma Scale before initiation of treatment was 3-4 in 8, 5-6 in 9 and 7 in 7 patients. Moderately to severely elevated ICP was observed in 20 patients. Seven developed acute and subacute space occupying intracranial hematomas. Nineteen children (79%) survived, most often with good recovery and 5 (21%) died. Severely elevated ICP, presence of severe consumption coagulopathy and loss of components in brain auditory evoked potentials were significantly more frequent in the fatal group. We conclude that the prognosis of the severely head injured child can be improved by prompt resuscitation and aggressive neurointensive care but probably not, however, to the extent postulated in recent literature.

Retinoid-dependent recruitment of a histone H1 displacement activity by retinoic acid receptor

Targeted recruitment of histone acetyltransferase (HAT) activities by sequence-specific transcription factors, including the retinoic acid receptors (RARs) and retinoid X receptors (RXRs), has been proposed to lead to destabilization of nucleosomal cores by acetylation of core histones. However, biochemical evidence indicates that destabilization and depletion of linker H1 histones must also occur at the promoter regions of actively transcribing genes. Mechanisms by which nuclear receptors and other transcription factors affect the removal of histone H1 from transcriptionally silent chromatin have not been previously described. In this report, we show that RARs interact in a ligand-dependent manner with HMG-I, which is known to displace histone H1 from chromatin. We further show that HMG-I and a novel related protein, HMG-R, also interact with other transcription factors. Using sense and antisense constructs of HMG-I/R in transient transfection assays with a retinoid responsive reporter, we also demonstrate that HMG-I/R is important for retinoid dependent transcriptional activity of RAR. These findings suggest a step wise mechanism by which RARs and other transcription factors can cause a targeted unfolding of compact chromatin as a first step in transcriptional activation, which would then be followed by recruitment of HAT activity and subsequent events.

Dependence on external calcium for the noradrenaline contractility of the resistance vessels in spontaneously hypertensive and renal hypertensive rats, as compared with normotensive controls

Isolated hindquarters of rats were perfused at constant flow with a plasma substitute so that pressor responses to various concentrations of noradrenaline (NA) could be measured in consective sections of the vascular bed with normal (greater than 1.5 mM) or low (0.2 mM) Ca2+ in the perfusate. The animals used were 6-week-old spontaneously hypertensive rats of the Okamoto strin (SHRy), normotensive controls of the same age NCRy); 6--7-month-old SHR (SHRA) and NCR (NCRA); and rats made hypertensive by clipping of one renal artery (RHR) plus matched normotensive controls (NCRR). Concentration-response curves to NA showed that constrictor responses to NA become more dependent on external calcium as one proceeds peripherally in the vascular system in both SHRA and NCRA, with responses in proximal vessels being least and small pre- and postcapillary vessels being most dependent in both cases. In low calcium SHRA retained their responses better than NCRA, whereas RHR retained their responses to NA poorer than did NCRR. No significant differences in responses in low calcium were observed in SHRY compared to NCRY though a trend in the same direction as in SHRA could be traced. It is concluded that there is no evidence that altered handling of calcium initiates vascular hyperreactivity in SHR, but that the handling of vascular calcium in SHR differs from RHR and both differ from NCR.

Solution structure of cytochrome c6 from the thermophilic cyanobacterium Synechococcus elongatus

Cytochrome c6 is a small, soluble electron carrier between the two membrane-bound complexes cytochrome b6f and photosystem I (PSI) in oxygenic photosynthesis. We determined the solution structure of cytochrome c6 from the thermophilic cyanobacterium Synechococcus elongatus by NMR spectroscopy and molecular dynamics calculations based on 1586 interresidual distance and 28 dihedral angle restraints. The overall fold exhibits four alpha-helices and a small antiparallel beta-sheet in the vicinity of Met58, one of the axial heme ligands. The flat hydrophobic area in this cytochrome c6 is conserved in other c6 cytochromes and even in plastocyanin of higher plants. This docking region includes the site of electron transfer to PSI and possibly to the cytochrome b6f complex. The binding of cytochrome c6 to PSI in green algae involves interaction of a negative patch with a positive domain of PSI. This positive domain has not been inserted at the evolutionary level of cyanobacteria, but the negatively charged surface region is already present in S. elongatus cytochrome c6 and may thus have been optimized during evolution to improve the interaction with the positively charged cytochrome f. As the structure of PSI is known in S.elongatus, the reported cytochrome c6 structure can provide a basis for mutagenesis studies to delineate the mechanism of electron transfer between both.

Structure of Synechococcus elongatus [Fe2S2] ferredoxin in solution

Ferredoxins of the [Fe2S2] type function in photosynthetic electron transport as essential electron acceptors of photosystem I. The solution structure of the 97 amino acid ferredoxin from the thermophilic cyanobacterium Synechococcus elongatus was determined by nuclear magnetic resonance spectroscopy and restrained molecular dynamics calculations. The structure consists of a four-stranded parallel/ antiparallel beta-sheet, a short two-stranded antiparallel beta-sheet, and three short helices. The overall structure is similar to the structure of the ferredoxin from Anabaena. In contrast to related ferredoxins from mesophilic organisms, this thermostable protein contains a salt bridge inside a 17-amino acid hydrophobic core.

Posterior vertebral column resection in early onset spinal deformities

PURPOSE

Early onset spinal deformities (EOSD) can be life-threatening in very young children. In the growing spine, surgical intervention is often unavoidable and should be carried out as soon as possible. A deformed section of the spine not only affects the development of the remaining healthy spine, but also that of the chest wall (which influences pulmonary function), the extremities and body balance. Posterior vertebral column resection (PVCR) represents an effective surgical solution to address such problems. However, reports in the literature concerning PVCR are mostly limited to its use in adolescents or adults. The purpose of this study was to illustrate our experience with PVCR in EOSD and to describe the surgical technique with respect to the unique anatomy of young children.

MATERIALS AND METHODS

Four children [mean age 3.7 (range 2.5-5.2) years] with severe spinal deformity underwent PVCR through a single approach. Multimodal intraoperative monitoring was used in all cases. Surgery included one stage posterior circumferential resection of one vertebral body along with the adjoining intervertebral discs and removal of all posterior elements. A transpedicular screw-rod system was used for correction and stabilisation. Fusion was strictly limited to the resection site, allowing for later conversion into a growing rod construct at the remaining spine, if necessary. Relevant data were extracted retrospectively from patient charts and long spine radiographs.

RESULTS

The mean operation time was 500 (range 463-541) min, with an estimated blood loss of 762 (range 600-1,050) ml. Mean follow-up time was 6.3 (range 3.5-12.4) years. After PVCR, the mean Cobb angle for scoliosis was reduced from 69° (range 50-99°) to 29° (5-44°) and the sagittal curvature (kyphosis) from 126° (87-151°) to 61° (47-75°). The mean correction of scoliosis was 57 % (18-92°) and of kyphosis, 51 % (44-62°). There were no spinal cord-related complications. In three patients, spinal instrumentation for growth guidance (fusion less growing rod technique) was applied. Two patients had complications: one patient had a complication of anesthesia, halo pin failure, and revision surgery with extension of the instrumentation cranially due to loss of correction; the second patient had a postoperative infection, which required plastic reconstructive measures.

CONCLUSION

PVCR appears to be an effective technique to treat severe EOSD. There are important differences in its use in young children when compared with older patients. In patients with EOSD, additional surgical procedures are often necessary during growth, and hence non-fusion instrumentation beyond the vertebral resection site is advantageous, as it permits spinal growth and the later addition of fusion.

Identification of the AP1-antagonism domain of retinoic acid receptors

Retinoids are therapeutically effective in the treatment of psoriasis, photoaging, acne, and certain cancers. Some of the therapeutic actions of retinoids can be ascribed to retinoic acid receptor (RAR)-mediated antagonism of AP1-dependent gene expression. The increased activity of transcription factor AP1, a complex of oncoproteins Jun and Fos, is associated with cell growth and proliferation. Retinoids, on the other hand, inhibit cell proliferation and affect differentiation, activities that possibly stem from an antagonism of AP1-mediated gene expression by RARs. To gain insight into the molecular mechanism of RAR-AP1 interaction, we have identified the regions of the RAR required for AP1 antagonism. We demonstrate that the AP1 antagonism domain of RAR is a complex of the core of the DNA binding domain and the hydrophobic zipper region. Further, both monomeric RAR and RAR-RXR heterodimers inhibit the expression of an AP1 reporter. CREB binding protein (CBP) has been described as a cofactor for AP1, various nuclear hormone receptor proteins including RARs, and certain other transcription factors and is required for their transactivation properties. Therefore, CBP has been proposed as a common limiting cofactor that can account for inhibition of AP1-dependent gene expression by RARs. Interestingly, however, our results along with previously reported observations suggest that in addition to CBP, there may be other limiting cofactor(s) responsible for mutual transrepression of RAR and AP1.

Influence of learning on range expansion and adaptation to novel habitats

Learning has been postulated to 'drive' evolution, but its influence on adaptive evolution in heterogeneous environments has not been formally examined. We used a spatially explicit individual-based model to study the effect of learning on the expansion and adaptation of a species to a novel habitat. Fitness was mediated by a behavioural trait (resource preference), which in turn was determined by both the genotype and learning. Our findings indicate that learning substantially increases the range of parameters under which the species expands and adapts to the novel habitat, particularly if the two habitats are separated by a sharp ecotone (rather than a gradient). However, for a broad range of parameters, learning reduces the degree of genetically-based local adaptation following the expansion and facilitates maintenance of genetic variation within local populations. Thus, in heterogeneous environments learning may facilitate evolutionary range expansions and maintenance of the potential of local populations to respond to subsequent environmental changes.

Use of multimodal intra-operative monitoring in averting nerve injury during complex hip surgery

Peripheral nerve injury is an uncommon but serious complication of hip surgery that can adversely affect the outcome. Several studies have described the use of electromyography and intra-operative sensory evoked potentials for early warning of nerve injury. We assessed the results of multimodal intra-operative monitoring during complex hip surgery. We retrospectively analysed data collected between 2001 and 2010 from 69 patients who underwent complex hip surgery by a single surgeon using multimodal intra-operative monitoring from a total pool of 7894 patients who underwent hip surgery during this period. In 24 (35%) procedures the surgeon was alerted to a possible lesion to the sciatic and/or femoral nerve. Alerts were observed most frequently during peri-acetabular osteotomy. The surgeon adapted his approach based on interpretation of the neurophysiological changes. From 69 monitored surgical procedures, there was only one true positive case of post-operative nerve injury. There were no false positives or false negatives, and the remaining 68 cases were all true negative. The sensitivity for predicting post-operative nerve injury was 100% and the specificity 100%. We conclude that it is possible and appropriate to use this method during complex hip surgery and it is effective for alerting the surgeon to the possibility of nerve injury.

Evidence for a single-spin azimuthal asymmetry in semi-inclusive pion electroproduction

Single-spin asymmetries for semi-inclusive pion production in deep-inelastic scattering have been measured for the first time. A significant target-spin asymmetry of the distribution in the azimuthal angle straight phi of the pion relative to the lepton scattering plane was formed for pi(+) electroproduction on a longitudinally polarized hydrogen target. The corresponding analyzing power in the sinstraight phi moment of the cross section is 0.022+/-0.005+/-0.003. This result can be interpreted as the effect of terms in the cross section involving chiral-odd spin distribution functions in combination with a chiral-odd fragmentation function that is sensitive to the transverse polarization of the fragmenting quark.

Tools for evaluating research output. Are citation-based rankings of economics journals stable?

Journal rankings are important for evaluating research output, for academic promotions, and for allocating funds. Examining the assignment of economics journals to different quartiles of citation-based rankings, the authors found that about 60% of journals remain in the same quartile and about 95% of journals remain in the same or move in a neighborhood quartile within 5- to 10-year intervals. Top journal rankings exhibit even more inertia, which is a desirable property for decisions on promotion, tenure, or institutional evaluation. A reexamination of journal assignment to different quality categories every 5 or 10 years, therefore, suffices for practical evaluation purposes.

Intensive care after fresh water immersion accidents in children

Six children who remained in deep coma after immersion accidents in fresh water received therapy to maintain normal intracranial pressure (ICP). This involved controlled ventilation to ensure hypocapnia and hyperoxaemia, maintenance of low normothermia, fluid restriction, dexamethasone (1-1.5 mg/kg initially, 1-1.5 mg/kg/day as maintenance) and barbiturates (phenobarbitone and thiopentone). The latter were given in a wide range of dosage. Increased ICP was common to all patients, but could always be kept at acceptable levels. All patients suffered from pulmonary oedema; three developed broncho-pneumonia and two developed adult respiratory distress syndrome. All children survived with good recovery, two needed active rehabilitation for several months.

Static light scattering and small-angle neutron scattering study on aggregated recombinant gelatin in aqueous solution

Recombinant gelatins are currently evaluated as new excipients for pharmaceutical formulations. They can differ from nonrecombinant gelatins because of intentional alteration of the amino acid sequence and specific properties of the expression systems used. This may affect their solution behavior. In the present work, aqueous solutions of a histidine-containing recombinant gelatin (RG-15-His) were analyzed. Dynamic light scattering (DLS) and loss of absorbance at 200 nm upon centrifugation indicated the formation of aggregates within 1 day upon sample preparation. Static light scattering (SLS) and small-angle neutron scattering (SANS) experiments showed that the aggregate's size was > or =300 nm, and that aggregates are composed of thin, rigid rods of 37 +/- 5 nm in length. The observed aggregation was not detectable by circular dichroism (CD), Fourier transform infrared spectroscopy (FTIR), and cryo transmission electron microscopy (cryo-TEM). SANS experiments, which are not frequently used in the pharmaceutical field, provided additional morphological information about the recombinant gelatin in solution. The results show that combining SLS and SANS is a broadly applicable, complementary approach for detecting aggregation of proteins and other biomolecules and for obtaining structural information about the aggregates.

Social determinants of health influence disease activity and functional disability in Polyarticular Juvenile Idiopathic Arthritis

BACKGROUND

Social determinants of health (SDH) greatly influence outcomes during the first year of treatment in rheumatoid arthritis, a disease similar to polyarticular juvenile idiopathic arthritis (pJIA). We investigated the correlation of community poverty level and other SDH with the persistence of moderate to severe disease activity and functional disability over the first year of treatment in pJIA patients enrolled in the Childhood Arthritis and Rheumatology Research Alliance Registry.

METHODS

In this cohort study, unadjusted and adjusted generalized linear mixed effects models analyzed the effect of community poverty and other SDH on disease activity, using the clinical Juvenile Arthritis Disease Activity Score-10, and disability, using the Child Health Assessment Questionnaire, measured at baseline, 6, and 12 months.

RESULTS

One thousand six hundred eighty-four patients were identified. High community poverty (≥20% living below the federal poverty level) was associated with increased odds of functional disability (OR 1.82, 95% CI 1.28-2.60) but was not statistically significant after adjustment (aOR 1.23, 95% CI 0.81-1.86) and was not associated with increased disease activity. Non-white race/ethnicity was associated with higher disease activity (aOR 2.48, 95% CI: 1.41-4.36). Lower self-reported household income was associated with higher disease activity and persistent functional disability. Public insurance (aOR 1.56, 95% CI 1.06-2.29) and low family education (aOR 1.89, 95% CI 1.14-3.12) was associated with persistent functional disability.

CONCLUSION

High community poverty level was associated with persistent functional disability in unadjusted analysis but not with persistent moderate to high disease activity. Race/ethnicity and other SDH were associated with persistent disease activity and functional disability.

Transverse asymmetry AT' from the quasielastic 3He(e,e') process and the neutron magnetic form factor

We have measured the transverse asymmetry A(T') in 3He(e,e(')) quasielastic scattering in Hall A at Jefferson Laboratory with high precision for Q2 values from 0.1 to 0.6 (GeV/c)(2). The neutron magnetic form factor G(n)(M) was extracted based on Faddeev calculations for Q2 = 0.1 and 0.2 (GeV/c)(2) with an experimental uncertainty of less than 2%.

Carboxymethylcellulose as a new carrier substance for intravitreal injection of reproducible amounts of triamcinolone

BACKGROUND

Intravitreal application of triamcinolone acetonide has become increasingly popular for the treatment of various retinal disorders. However, dosage, mode of preparation and application differ worldwide. The aim of this study was to find a safe vehicle that would allow intravitreal injection of an exact amount of triamcinolone acetonide without potentially retinotoxic preservatives.

METHODS

Solutions of triamcinolone acetonide with a theoretical concentration of 4 mg/0.2 ml were prepared following one sedimentation (A) and two filtration (B, C) methods. In addition, a filtration method using carboxymethylcellulose 2% as a carrier (D) was established. During processing and after injection into an eye model, the crystals were quantified by weight and high-performance liquid chromatography (HPLC), and, hence, the rate of crystal loss during this process was determined.

RESULTS

The initial preparation contained 93-106% of the calculated quantity. Method A, containing the entire vehicle, delivered 45%+/-7.3% of the target quantity to the eye model, whereas the vehicle-free methods B and C delivered 15%+/-6.9% and 11%+/-3.2%, respectively. Using carboxymethylcellulose 2% as a preservative-free vehicle, we found 93%+/-3.7% of the calculated amount in the eye model. The missing crystals were mainly sticking to the walls of the syringes and needles used for transfer.

CONCLUSION

Common methods for preparing triamcinolone acetonide vary in the amount of drug actually injected intravitreally. Carboxymethylcellulose is an ideal carrier substance for intravitreal application of an exact dose of triamcinolone acetonide without preservatives.