Predicting diagnostic conversion from major depressive disorder to bipolar disorder: an EHR based study from Colombia.

Bipolar Disorder (BD) is a severe and chronic disorder characterized by recurrent episodes of depression, mania, and/or hypomania. Most BD patients initially present with depressive symptoms, resulting in a delayed diagnosis of BD and poor clinical outcomes. This study leverages electronic health record (EHR) data from the Clínica San Juan de Dios Manizales in Colombia to identify features predictive of the transition from Major Depressive Disorder (MDD) to BD. Analyzing EHR data from 13,607 patients diagnosed with MDD over 15 years, we identified 1,610 cases of conversion to BD. Using a multivariate Cox regression model, we identified severity of the initial MDD episode, the presence of psychosis and hospitalization at first episode, family history of mood or psychotic disorders, female gender to be predictive of the conversion to BD. Additionally, we observed associations with medication classes (prescriptions of mood stabilizers, antipsychotics, and antidepressants) and clinical features (delusions, suicide attempt, suicidal ideation, use of marijuana and alcohol use/abuse) derived from natural language processing (NLP) of clinical notes. Together, these risk factors predicted BD conversion within five years of the initial MDD diagnosis, with a recall of 72% and a precision of 38%. Our study confirms many previously identified risk factors identified through registry-based studies (such as female gender and psychotic depression at the index MDD episode), and identifies novel ones (specifically, suicidal ideation and suicide attempt extracted from clinical notes). These results simultaneously demonstrate the validity of using EHR data for predicting BD conversion as well as underscore its potential for the identification of novel risk factors and improving early diagnosis.

Two New Compounds Containing Pyridinone or Triazine Heterocycles Have Antifungal Properties against Candida albicans.

Candidiasis, caused by the opportunistic yeast Candida albicans, is the most common fungal infection today. Resistance of C. albicans to current antifungal drugs has emerged over the past decade leading to the need for novel antifungal agents. Our aim was to select new antifungal compounds by library-screening methods and to assess their antifungal effects against C. albicans. After screening 90 potential antifungal compounds from JUNIA, a chemical library, two compounds, 1-(4-chlorophenyl)-4-((4-chlorophenyl)amino)-3,6-dimethylpyridin-2(1H)-one (PYR) and (Z)-N-(2-(4,6-dimethoxy-1,3,5-triazin-2-yl)vinyl)-4-methoxyaniline (TRI), were identified as having potential antifungal activity. Treatment with PYR and TRI resulted in a significant reduction of C. albicans bioluminescence as well as the number of fungal colonies, indicating rapid fungicidal activity. These two compounds were also effective against clinically isolated fluconazole- or caspofungin-resistant C. albicans strains. PYR and TRI had an inhibitory effect on Candida biofilm formation and reduced the thickness of the mannan cell wall. In a Caenorhabditis elegans infection model, PYR and TRI decreased the mortality of nematodes infected with C. albicans and enhanced the expression of antimicrobial genes that promote C. albicans elimination. Overall, PYR and TRI showed antifungal properties against C. albicans by exerting fungicidal activities and enhancing the antimicrobial gene expression of Caenorhabditis elegans.

TAEL 2.0: An Improved Optogenetic Expression System for Zebrafish.

Inducible gene expression systems are valuable tools for studying biological processes. We previously developed an optogenetic gene expression system called TAEL that is optimized for use in zebrafish. When illuminated with blue light, TAEL transcription factors dimerize and activate gene expression downstream of the TAEL-responsive C120 promoter. By using light as the inducing agent, the TAEL/C120 system overcomes limitations of traditional inducible expression systems by enabling fine spatial and temporal regulation of gene expression. In this study, we describe ongoing efforts to improve the TAEL/C120 system. We made modifications to both the TAEL transcriptional activator and the C120 regulatory element, collectively referred to as TAEL 2.0. We demonstrate that TAEL 2.0 consistently induces higher levels of reporter gene expression and at a faster rate, but with comparable background and toxicity as the original TAEL system. With these improvements, we were able to create functional stable transgenic lines to express the TAEL 2.0 transcription factor either ubiquitously or with a tissue-specific promoter. We demonstrate that the ubiquitous line in particular can be used to induce expression at late embryonic and larval stages, addressing a major deficiency of the original TAEL system. This improved optogenetic expression system will be a broadly useful resource for the zebrafish community.

Concentration-dependent effects of latex F1-protein fraction incorporated into deproteinized bovine bone and biphasic calcium phosphate on the repair of critical-size bone defects.

F1-protein fraction (F1) is a natural bioactive compound extracted from the rubber tree, Hevea brasiliensis, and has been recently studied for its therapeutic potential in wound healing. In this study, we investigated the concentration-dependent effects of F1 (0.01%, 0.025%, 0.05%, and 0.1%) incorporated into deproteinized bovine bone (DBB) and porous biphasic calcium phosphate (pBCP), on the repair of rat calvarial critical-size bone defects (CSBD). The defects were analyzed by 3D-microtomography and 2D-histomorphometry at 12 weeks postsurgery. The binding efficiency of F1 to pBCP (96.3 ± 1.4%) was higher than that to DBB (67.7 ± 3.3%). In vivo analysis showed a higher bone volume (BV) gain in all defects treated with DBB (except in 0.1% of F1) and pBCP (except in 0.05% and 0.1% of F1) compared to the CSBD without treatment/control group (9.96 ± 2.8 mm3 ). DBB plus 0.025% F1 promoted the highest BV gain (29.7 ± 2.2 mm3 , p < .0001) compared to DBB without F1 and DBB plus 0.01% and 0.1% of F1. In the pBCP group, incorporation of F1 did not promote bone gain when compared to pBCP without F1 (15.9 ± 4.2 mm3 , p > .05). Additionally, a small BV occurred in defects treated with pBCP plus 0.1% F1 (10.4 ± 1.4 mm3, p < .05). In conclusion, F1 showed a higher bone formation potential in combination with DBB than with pBCP, in a concentration-dependent manner. Incorporation of 0.25% F1 into DBB showed the best results with respect to bone formation/repair in CSBD. These results suggest that DBB plus 0.25% F1 can be used as a promising bioactive material for application in bone tissue engineering.

Metformin as an add-on to insulin improves periodontal response during orthodontic tooth movement in type 1 diabetic rats.

BACKGROUND: Type 1 diabetes (T1D) is associated with delayed tissue healing and bone loss. Periodontal tissues during tooth movement (OTM) in T1D and under diabetic treatment are poorly understood. We aimed to study the effect of metformin as an add-on to insulin therapy on periodontal structures during OTM in T1D rats. METHODS: Rats were divided into normoglycemic (NG, n = 20) and streptozotocin-induced diabetic groups that were untreated (T1D, n = 20), treated with insulin (I-T1D, n = 20), or treated with insulin plus metformin (IM-T1D, n = 20). After 7 days of treatment, the first right upper molar (M1) was moved mesially. At days 0, 3, 7 and 14, the pattern of OTM and the periodontal tissues were analyzed by micro-CT, histomorphometry, and immunohistochemistry for TRAP. RESULTS: In T1D, major osteoclastogenic activity and bone loss versus other groups were confirmed by a greater TRAP-positive cell number and reabsorption surface on both the pressure and tension sides for 14 days (p < 0.01). Additionally, we observed low bone volume density. Metformin plus insulin resulted in a daily insulin dose reduction and major glycemic control versus I-T1D. Although no significant differences were observed between I-T1D and IM-T1D, the tooth displacement and inclination, periodontal ligament thickness, and alveolar bone density on the pressure side in IM-T1D were similar to that of NG (p > 0.05). CONCLUSION: Antidiabetic treatment reduces severe periodontal damage during applied orthodontic force in T1D untreated rats. Metformin as an add-on to insulin therapy resulted in glycemic control and a periodontal tissue response to orthodontic forces that was similar to that of normoglycemic rats.

Green tea prevents vascular disturbs and attenuates periodontal breakdown in long-term hyperglycaemia in T1D rats.

AIM: The effects of green tea on the modulation of vascularization during the progression of spontaneous periodontitis in long-term hyperglycaemia in streptozotocin-induced type 1 diabetic (T1D) rats were evaluated. MATERIALS AND METHODS: Wistar rats normoglycaemic (NG) and T1D were divided into two control groups, which received water (NG-W and T1D-W) and two experimental groups that received green tea (NG-GT and T1D-GT). Periodontal structures were evaluated by microtomographic and histological analyses. Number of immunostained cells for VEGF (NcVEGF+/mm2 ) and CD31 (NcCD31+/mm2 ), as well microvessel density (MVD) in the periodontal ligament (PDL) were evaluated. RESULTS: Long-term hyperglycaemia in T1D-W rats induced vascular alterations in PDL with a reduction of 36% in MVD, a decrease of 33% in NcCD31+/mm2 and an increase of 53% in NcVEGF+/mm2 . Concomitantly, a severe degree of periodontitis with higher reduction in bone volume and periodontal bone level was observed. In T1D-GT, green tea maintained the MVD, NcCD31+/mm2 and NcVEGF+/mm2 in the PDL similar to normoglycaemic groups. Clinically, in T1D-GT rats, green tea reduced dental plaque accumulation and the degree of periodontitis when compared to T1D-W. CONCLUSION: Daily green tea consumption has a therapeutic effect on the diabetic vascular disorder in PDL and the progression of periodontitis in long-term hyperglycaemia in T1D rats.

TAEL: a zebrafish-optimized optogenetic gene expression system with fine spatial and temporal control.

Here, we describe an optogenetic gene expression system optimized for use in zebrafish. This system overcomes the limitations of current inducible expression systems by enabling robust spatial and temporal regulation of gene expression in living organisms. Because existing optogenetic systems show toxicity in zebrafish, we re-engineered the blue-light-activated EL222 system for minimal toxicity while exhibiting a large range of induction, fine spatial precision and rapid kinetics. We validate several strategies to spatially restrict illumination and thus gene induction with our new TAEL (TA4-EL222) system. As a functional example, we show that TAEL is able to induce ectopic endodermal cells in the presumptive ectoderm via targeted sox32 induction. We also demonstrate that TAEL can be used to resolve multiple roles of Nodal signaling at different stages of embryonic development. Finally, we show how inducible gene editing can be achieved by combining the TAEL and CRISPR/Cas9 systems. This toolkit should be a broadly useful resource for the fish community.

Efeito das drogas antidiabéticas na movimentação dentária em ratos diabéticos tipo 1: avaliação microtomográfica e histológica / Effect of antidiabetic drugs on tooth movement in type 1 diabetic rats: microtomographic and histological evaluation

A diabetes mellitus (DM) é um grupo de doenças metabólicas caracterizadas por hiperglicemia resultante do déficit na secreção e/ou ações de insulina. Dentre as muitas complicações da diabetes incluem a osteopenia diabética, que causa osteoporose e aumento do risco de fraturas ósseas. A patofisiologia da baixa resistência óssea associada a DM é considerada multifatorial, podendo ser decorrente da deficiência de insulina, resistência à insulina, insuficiência de osteoblastos, deficiência de vitamina D, formação e acúmulo dos produtos finais da glicação avançada e complicações microvasculares. Por isso, existe um interesse crescente no estudo da diabetes associada a outras alterações metabólicas e o efeito das drogas antidiabéticas, de forma a reverter os efeitos maléficos. O objetivo desse estudo foi avaliar a influência das drogas antidiabéticas na movimentação dentária ortodôntica e na densidade/microarquitetura óssea alveolar em ratos diabéticos. Assim, ratos Normoglicêmicos (NG,n=20) e Diabéticos induzidos pela estreptozotocina (DM1,n=60) foram divididos em: TinDM1(n=20) tratados com Insulina, TinmetDM1(n=20) tratados com Insulina+Metformina, e os STDM1(n=20) e STNG(n=20) que não receberam tratamento. Após 14 dias da indução, o 1o molar superior direito recebeu força ortodôntica (50g) em sentido mesial. Nos periodos experimentais de 0, 3, 7 e 14 dias, as maxilas foram coletadas e submetidas às análises microtomográficas para quantificar a movimentação dentária e a densidade óssea e histológica, para avaliar as alterações periodontais ocorridas durante a movimentação. Os dados microtomográficos foram submetidos à ANOVA a dois critérios e teste de Tukey (p<0,05). A indução com estreptozotocina induziu ao quadro de diabetes grave (glicemia de jejum de 325mg/dL) os quais foram acentuados com o tempo no grupo STDM1 (404mg/dL). A utilização de insulina e da associação insulina e metformina reduziram consideravelmente os níveis glicêmicos (127mg/dL)...

Diabetes mellitus (DM) is a group of metabolic diseases characterized by hyperglycemia resulting in deficits in the secretion and/or insulin action. Among the many complications of diabetes, it includes diabetic osteopenia that causes osteoporosis and increased risk of bone fractures. The pathophysiology associated with low bone strength in DM is considered multifactorial and may be due to insulin deficiency, insulin resistance, osteoblast deficiency, vitamin D deficiency, formation and accumulation of advanced glycation end products and microvascular complications. Therefore, there is a growing interest in the study of diabetes associated with other metabolic abnormalities and the effect of antidiabetic drugs, in order to reverse the deleterious effects. The objective of this study was to evaluate the influence of antidiabetic drugs in orthodontic tooth movement and alveolar bone density/microarchitecture in diabetic rats. Thus, normoglycemic rats (NG, n=20) and streptozotocin-induced diabetic (DM1, n=60) were divided into TinDM1 (n=20) treated by insulin, TinmetDM1 (n=20) treated by Insulin + Metformin and STDM1 (n = 20) and STNG (n = 20) that received no treatment. After 14 days of induction, the M1 received orthodontic force (50g) to move mesially. After 0, 3, 7 and 14 days jaws were collected and subjected to microtomographic images analysis to quantify, tooth movement and bone density and histological analysis to evaluate periodontal changes occurred during the movement. Microtomographic data were submitted to two-way ANOVA and Tukey test (p <0.05). The induction with streptozotocin induced severe diabetes frame (fasting blood glucose 325 mg/dL) which accentuated over the time of the disease in STDM1 group (404mg/dL). The use of insulin and insulin and metformin reduced blood glucose levels to satisfactory values (127mg/dL). The strength of 50g applied on M1 promoted linear tooth movement, being lower in STNG group...

A small library of synthetic di-substituted 1, 4-naphthoquinones induces ROS-mediated cell death in murine fibroblasts.

Synthesis of compound libraries and their concurrent assessment as selective reagents for probing and modulating biological function continues to be an active area of chemical biology. Microwave-assisted solid-phase Dötz benzannulation reactions have been used to inexpensively synthesize 2, 3-disubstituted-1, 4-naphthoquinone derivatives. Herein, we report the biological testing of a small library of such compounds using a murine fibroblast cell line (L929). Assessment of cellular viability identified three categories of cytotoxic compounds: no toxicity, low/intermediate toxicity and high toxicity. Increased levels of Annexin-V-positive staining and of caspase 3 activity confirmed that low, intermediate, and highly toxic compounds promote cell death. The compounds varied in their ability to induce mitochondrial depolarization and formation of reactive oxygen species (ROS). Both cytotoxic and non-cytotoxic compounds triggered mitochondrial depolarization, while one highly cytotoxic compound did not. In addition, all cytotoxic compounds promoted increased intracellular ROS but the cells were only partially protected from compound-induced apoptosis when in the presence of superoxide dismutase, catalase, or ascorbic acid suggesting utilization of additional pro-death mechanisms. In summary, nine of twelve (75%) 1, 4-naphthoquinone synthetic compounds were cytotoxic. Although the mitochondria did not appear to be a central target for induction of cell death, all of the cytotoxic compounds induced ROS formation. Thus, the data demonstrate that the synthesis regime effectively created cytotoxic compounds highlighting the potential use of the regime and its products for the identification of biologically relevant reagents.

Relationships between central and peripheral corneal thickness in different degrees of myopia.

PURPOSE: To analyze the relationship between the central corneal thickness (CCT) and mid-peripheral corneal thickness (PCT) with the degree of myopia [axial length (AL) and spherical equivalent refractive error (SE)]. METHODS: 175 right myopic eyes from 175 patients were divided according to the degree of SE: group #1 (n=76, <6.00 D), group #2 (n=72, between 6.00 and 12.00 D) and group #3 (n=27, >12.00 D). The CCT and PCT (3mm from the apex to the superior, inferior, nasal and temporal locations) were measured with the Orbscan-II. Relative peripheral index (RPI) was calculated by dividing the PCT by the CCT. The AL was measured with the IOL Master, and the SE was obtained with subjective refraction. RESULTS: AL was 25.18±1.16 mm, 26.59±1.26 mm and 29.45±2.58 mm and SE was -3.31±1.40 D, -8.32±1.64 D and -16.44±4.48 D for groups #1, #2 and #3, respectively. Non-statistically significant differences in central and peripheral corneal thickness were found between groups (P>0.05 ANOVA). Non-significant relationship was found between central and peripheral corneal thickness with the AL and SE in the three study groups and in the total sample (r<0.24; P>0.05). The RPI values were similar between groups without significant difference between groups (P>0.05 ANOVA). Linear relationship was found between RPI superior location in group #2 (r=-0.23; P=0.04) and RPI nasal location in group #3 with the EE (r=0.41; P=0.03). CONCLUSION: There are no significant differences among low, moderate and extremely myopic eyes related to the CCT and PCT. Corneal thickness is very similar in myopic eyes with small differences that are not clinically relevant to myopic patient management.

Culture and alcohol use: historical and sociocultural themes from 75 years of alcohol research.

OBJECTIVE: For the period of almost 75 years, we examined the literature for studies regarding the influences of culture on alcohol use and misuse. METHOD: This review is a chronology of research articles published from 1940 to 2013. From a structured literature search with select criteria, 38 articles were identified and 34 reviewed. RESULTS: This analysis revealed a progression across this period of research from studies that began as descriptive ethnographic evaluations of one or more indigenous societies or cultural groups, evolving to studies using complex multivariate models to test cross-cultural effects in two or more cultural groups. Major findings across this period include the assertions that (a) a function of alcohol use may be to reduce anxiety, (b) certain cultural groups possess features of alcohol use that are not associated with negative consequences, (c) the disruptive effects of acculturative change and the stressors of new demands are associated with an increase in alcohol consumption, (d) cultural groups shape expectations about the effects of alcohol use and their definition of drunkenness, and (e) the hypothesized relationships of culture with alcohol use and misuse have been demonstrated in multivariate model analyses. CONCLUSIONS: Across this 75-year period, the early proposition that culture is an important and prominent correlate of alcohol use and misuse has persisted. Within the current era of alcohol studies, this proposition has been supported by multivariate model analyses. Thus, the proposition that culture might affect alcohol use remains prominent and is as relevant today as it was when it was first proposed nearly 75 years ago.

An optogenetic gene expression system with rapid activation and deactivation kinetics.

Optogenetic gene expression systems can control transcription with spatial and temporal detail unequaled with traditional inducible promoter systems. However, current eukaryotic light-gated transcription systems are limited by toxicity, dynamic range or slow activation and deactivation. Here we present an optogenetic gene expression system that addresses these shortcomings and demonstrate its broad utility. Our approach uses an engineered version of EL222, a bacterial light-oxygen-voltage protein that binds DNA when illuminated with blue light. The system has a large (>100-fold) dynamic range of protein expression, rapid activation (<10 s) and deactivation kinetics (<50 s) and a highly linear response to light. With this system, we achieve light-gated transcription in several mammalian cell lines and intact zebrafish embryos with minimal basal gene activation and toxicity. Our approach provides a powerful new tool for optogenetic control of gene expression in space and time.

Basal values, intra-day and inter-day variations in tear film osmolarity and tear fluorescein clearance.

PURPOSE: The aim of this study was to determine the normal inter-day and intra-day variations in tear film osmolarity and the tear fluorescein clearance test (T-FCT) in healthy subjects. METHODS: Tear samples from 24 young, healthy adults were collected from 11:00 AM to 1:00 PM (midday) and 5:00 PM to 7:00 PM (evening) on three non-consecutive days. Tear osmolarity measurement and the T-FCT were performed to assess the basal values and inter-day and intra-day variations of the test results. A freezing point depression osmometer was used to analyze the tear osmolarity, and the T-FCT was performed using a fluorophotometer. RESULTS: The mean osmolarity value was 270 ± 4.4 mOsm/l and the mean T-FCT result was 2.97 ± 0.17 fluorescence arbitrary units. The inter-day or intra-day tear osmolarity values did not differ significantly. The T-FCT results varied significantly during the day, with significantly (p = 0.0004) higher results in the evening; no significant differences were found in the inter-day analysis. CONCLUSIONS: Tear osmolarity was unaffected by intra-day variations; however, the T-FCT showed an inter-day variation, which indicated that the time of day when the test is performed must be considered when it is used to evaluate the diagnosis of dry eye disease, disease progression or therapeutic effectiveness.

Blue light-induced dimerization of a bacterial LOV-HTH DNA-binding protein.

With their utilization of light-driven allostery to control biochemical activities, photosensory proteins are of great interest as model systems and novel reagents for use by the basic science and engineering communities. One such protein, the light-activated EL222 transcription factor, from the marine bacterium Erythrobacter litoralis HTCC2594, is appealing for such studies, as it harnesses blue light to drive the reorientation of light-oxygen-voltage (LOV) sensory and helix-turn-helix (HTH) effector domains to allow photoactivation of gene transcription in natural and artificial systems. The protein conformational changes required for this process are not well understood, in part because of the relatively short lifetime of the EL222 photoexcited state (τ ∼ 29 s), which complicates its characterization via certain biophysical methods. Here we report how we have circumvented this limitation by creating an EL222 variant harboring V41I, L52I, A79Q, and V121I point mutations (AQTrip) that stabilizes the photoactivated state. Using the wild-type and AQTrip EL222 proteins, we have probed EL222 activation using a combination of solution scattering, nuclear magnetic resonance (NMR), and electromobility shift assays. Size-exclusion chromatography and light scattering indicate that AQTrip oligomerizes in the absence of DNA and selects for an EL222 dimer-DNA complex in the presence of DNA substrates. These results are confirmed in wild-type EL222 with a high-affinity DNA-binding site that stabilizes the complex. NMR analyses of the EL222-DNA complex confirm a 2:1 stoichiometry in the presence of a previously characterized DNA substrate. Combined, these novel approaches have validated a key mechanistic step, whereby blue light induces EL222 dimerization through LOV and HTH interfaces.

Identification of natural and artificial DNA substrates for light-activated LOV-HTH transcription factor EL222.

Light-oxygen-voltage (LOV) domains serve as the photosensory modules for a wide range of plant and bacterial proteins, conferring blue light-dependent regulation to effector activities as diverse as enzymes and DNA binding. LOV domains can also be engineered into a variety of exogenous targets, allowing similar regulation for new protein-based reagents. Common to these proteins is the ability for LOV domains to reversibly form a photochemical adduct between an internal flavin chromophore and the surrounding protein, using this to trigger conformational changes that affect output activity. Using the Erythrobacter litoralis protein EL222 model system that links LOV regulation to a helix-turn-helix (HTH) DNA binding domain, we demonstrated that the LOV domain binds and inhibits the HTH domain in the dark, releasing these interactions upon illumination [Nash, A. I., et al. (2011) Proc. Natl. Acad. Sci. U.S.A. 108, 9449-9454]. Here we combine genomic and in vitro selection approaches to identify optimal DNA binding sites for EL222. Within the bacterial host, we observe binding at several genomic sites using a 12 bp sequence consensus that is also found by in vitro selection methods. Sequence-specific alterations in the DNA consensus reduce EL222 binding affinity in a manner consistent with the expected binding mode, a protein dimer binding to two repeats. Finally, we demonstrate the light-dependent activation of transcription of two genes adjacent to an EL222 binding site. Taken together, these results shed light on the native function of EL222 and provide useful reagents for further basic and applications research of this versatile protein.

A disease-associated polymorphism alters splicing of the human CD45 phosphatase gene by disrupting combinatorial repression by heterogeneous nuclear ribonucleoproteins (hnRNPs).

Alternative splicing is typically controlled by complexes of regulatory proteins that bind to sequences within or flanking variable exons. The identification of regulatory sequence motifs and the characterization of sequence motifs bound by splicing regulatory proteins have been essential to predicting splicing regulation. The activation-responsive sequence (ARS) motif has previously been identified in several exons that undergo changes in splicing upon T cell activation. hnRNP L binds to this ARS motif and regulates ARS-containing exons; however, hnRNP L does not function alone. Interestingly, the proteins that bind together with hnRNP L differ for different exons that contain the ARS core motif. Here we undertake a systematic mutational analysis of the best characterized context of the ARS motif, namely the ESS1 sequence from CD45 exon 4, to understand the determinants of binding specificity among the components of the ESS1 regulatory complex and the relationship between protein binding and function. We demonstrate that different mutations within the ARS motif affect specific aspects of regulatory function and disrupt the binding of distinct proteins. Most notably, we demonstrate that the C77G polymorphism, which correlates with autoimmune disease susceptibility in humans, disrupts exon silencing by preventing the redundant activity of hnRNPs K and E2 to compensate for the weakened function of hnRNP L. Therefore, these studies provide an important example of the functional relevance of combinatorial function in splicing regulation and suggest that additional polymorphisms may similarly disrupt function of the ESS1 silencer.

Depressed skull fracture by a three-pin head holder: a case illustration.

UNLABELLED: BACKGROUND AND CASE REPORT: Many surgical procedures require a rigid immobilization of the patients' head, which is usually achieved by using a pin-type head holder. We briefly illustrate the case of a 4-year-old girl who sustained a depressed skull fracture by penetration of a pin of the head holder. The fracture was noted at the end of the surgery performed for treatment of a cerebellar astrocytoma and was managed conservatively. DISCUSSION: Several factors seem to be involved in the production of this complication as are faulty application of the pins, excessive pin pressure, skull thinning, young patient's age, and pathological conditions that evolve with long-standing raised intracranial pressure. Prevention and management measures are briefly discussed.

The three Rs of transcription: recruit, retain, and recycle.

The dynamic protein interactions required for transcription are functionally important yet poorly understood; in this issue of Molecular Cell, Zobeck et al. (2010) resolve the sequential recruitment and selective recycling of transcription factors at an actively transcribing locus in Drosophila.

Context-dependent regulatory mechanism of the splicing factor hnRNP L.

Splicing regulatory proteins often have distinct activities when bound to exons versus introns. However, less clear is whether variables aside from location can influence activity. HnRNP L binds to a motif present in both CD45 variable exons 4 and 5 to affect their coordinate repression. Here, we show that, in contrast to its direct repression of exon 4, hnRNP L represses exon 5 by countering the activity of a neighboring splicing enhancer. In the absence of the enhancer, hnRNP L unexpectedly activates exon inclusion. As the splice sites flanking exon 4 and 5 are distinct, we directly examined the effect of varying splice site strength on the mechanism of hnRNP L function. Remarkably, binding of hnRNP L to an exon represses strong splice sites but enhances weak splice sites. A model in which hnRNP L stabilizes snRNP binding can explain both effects in a manner determined by the inherent snRNP-substrate affinity.