An analysis of the impact of annual cancer genetic testing guideline updates on a past patient population.

Germline genetic testing for cancer predisposition genes has become an essential component of cancer treatment and risk reduction. The National Comprehensive Cancer Network (NCCN) releases annual genetic testing guidelines that identify characteristics of patients that could be affected by a hereditary cancer syndrome. These guidelines have broadened over time and the implications for past patients of cancer genetics clinics are not well understood. This study is a retrospective chart review aimed at determining the percentage and characteristics of past patients that meet updated NCCN guidelines (Breast, Ovarian, and Pancreas [BOP] v1.2022 and Colorectal [CRC] v1.2021), patients that attended a follow-up appointment, and patients who went on to receive genetic testing. Clinical data and characteristics were compared between the study population as a whole and the cohort of patients that met updated NCCN guidelines BOP v1.2022 and CRC v1.2021. The study population consisted of 280 patients with 76 (27.1%) patients meeting updated NCCN guidelines BOP v1.2022 and CRC v1.2021. The year of initial cancer genetic counseling appointment was statistically significant (p = 0.023) with patients more likely to meet NCCN guidelines BOP v1.2022 and CRC v1.2021 with earlier initial cancer genetic counseling appointments. In the cohort that met updated NCCN guidelines BOP v1.2022 and CRC v1.2021, the most common reason was a change in the NCCN guidelines (BOP or CRC) (54/76, 71.1%) with triple-negative breast cancer diagnosed at any age being the most impactful guideline change (19/54, 35.2%). Twenty-one patients attended a follow-up appointment (7.5%) and of those that received genetic testing (17/21, 81%) most received negative results (13/17, 61.9%), with one pathogenic, low penetrance result (1/17, 5.9%, CHEK2 p.I157T). Provider-initiated follow-up was attributed to most follow-up appointments (16/21, 76.2%) implying patients do not tend to follow-up on their own. Education to non-genetics providers as well as targeted implementation of follow-up protocols possibly managed by genetic counseling assistants and utilizing electronic medical record (EMR) patient messaging could lead to improved patient follow-up.

Case Report: 2-Year-old With Wilms Tumors, Familial Heterozygous DIS3L2 Mutation, and Cutis Marmorata Telangiectatica Congenita.

Biallelic variants in DI3SL2 cause Perlman Syndrome, associated increased risk for Wilms tumor. Cutis Marmorata Telangiectatica Congenita (CMTC) is a rare congenital disorder characterized by cutaneous vascular anomalies. We report a 2-year-old boy with both Wilms tumor and CMTC. Genetic testing, prompted by his complex presentation, revealed 1 somatic mutation and 1 familial germline mutation in the DIS3L2 gene, suggesting a 2-hit causation of Wilms tumor. Separately, a single GNA11 somatic mutation was identified to explain the CMTC. We suggest that genetic testing for germline mutations associated with Wilms tumor susceptibility be considered even in cases without known family history.

Systematic review and meta-analysis for the impact of rod materials and sizes in the surgical treatment of adult spine deformity.

PURPOSE: To assess clinical and safety outcomes associated with different rod materials and diameters in adult spinal deformity (ASD) surgery. METHODS: A systematic literature review and meta-analysis evaluated ASD surgery using pedicle screw fixation systems with rods of different materials and sizes. Postoperative outcomes (i.e., Cobb, sagittal vertical axis, and pelvic tilt angle) and complications (i.e., pseudarthrosis and rod breakage) were assessed. Random effects models (REMs) pooled data for outcomes reported in ≥ 2 studies. RESULTS: Among 50 studies evaluating ASD surgery using pedicle screw fixation systems, 17 described rod material/diameter. Postoperative outcomes did not statistically differ between cobalt-chromium (CoCr) vs. titanium (Ti) rods (n = 2 studies; mean [95% confidence interval (CI)] sagittal vertical axis angle: CoCr 37.00° [18.58°-55.42°] and Ti 32.58° [24.62°-40.54°]; mean [95% CI] pelvic tilt angle: CoCr 26.20° [22.87°-29.53°] and Ti 20.15° [18.0°-22.31°]). The pooled proportion (95% CI) of pseudarthrosis was 15% (7-22%) for CoCr and 12% (- 8-32%) for stainless steel (SS) (n = 2 studies each; Chi2 = 0.07, p = 0.79). The pooled proportion (95% CI) of broken rods was 12% (1-22%) for Ti (n = 3 studies) and 10% (2-19) for CoCr (n = 1 study). Among 6.0-6.35 mm rods, the pooled (95% CI) postoperative Cobb angle (n = 2) was 12.01° (9.75°-14.28°), sagittal vertical axis angle (n = 4) was 35.32° (30.02°-40.62°), and pelvic tilt angle was 21.11° (18.35°-23.86°). CONCLUSIONS: For ASD patients undergoing posterior fixation and fusion, there are no statistically significant differences in postoperative outcomes or complications among rods of varying materials and diameters. Benchmark postsurgical outcomes and complication rates by rod material and diameter are provided. LEVEL OF EVIDENCE: III.

Systematic review and meta-analysis for the impact of rod materials and sizes in the surgical treatment of adolescent idiopathic scoliosis.

PURPOSE: To assess surgical and safety outcomes associated with different rod materials and diameters in adolescent idiopathic scoliosis (AIS) surgery. METHODS: A systematic literature review and meta-analysis evaluated the surgical management of AIS patients using pedicle screw fixation systems (i.e., posterior rods and pedicle screws) with rods of different materials and sizes. Postoperative surgical outcomes (e.g., kyphosis and coronal correction) and complications (i.e., hyper/hypo-lumbar lordosis, proximal junctional kyphosis, revisions, reoperations, and infections) were assessed. Random-effects models (REMs) pooled data for outcomes reported in ≥ 2 studies. RESULTS: Among 75 studies evaluating AIS surgery using pedicle screw fixation systems, 46 described rod materials and/or diameters. Two studies directly comparing titanium (Ti) and cobalt-chromium (CoCr) rods found that CoCr rods provided significantly better postoperative kyphosis angle correction vs. Ti rods during a shorter follow-up (0-3 months, MD = - 2.98°, 95% CI - 5.79 to - 0.17°, p = 0.04), and longer follow-up (≥ 24 months, MD = - 3.99°, 95% CI - 6.98 to - 1.00, p = 0.009). Surgical infection varied from 2% (95% CI 1.0-3.0%) for 5.5 mm rods to 4% (95% CI 2.0-7.0%) for 6 mm rods. Reoperation rates were lower with 5.5 mm rods 1% (95% CI 0.0-3.0%) vs. 6 mm rods [6% (95% CI 2.0-9.0%); p = 0.04]. Differences in coronal angle, lumbar lordosis, proximal junctional kyphosis, revisions, and infections did not differ significantly (p > 0.05) among rods of different materials or diameters. CONCLUSION: For AIS, CoCr rods provided better correction of thoracic kyphosis compared to Ti rods. Patients with 5.5 mm rods had fewer reoperations vs. 6.0 and 6.35 mm diameter rods. LEVEL OF EVIDENCE: III.

Novel SMC1A frameshift mutations in children with developmental delay and epilepsy.

Cornelia de Lange syndrome (CdLS) is a rare dominantly inherited genetic multisystem developmental condition with considerable phenotypic and allelic heterogeneity. Missense and in-frame deletions within the SMC1A gene can be associated with epilepsy and milder craniofacial features. We report two females who presented with developmental delay and developed isolated medically refractory seizures with unrevealing initial laboratory, imaging and genetic evaluations. Whole exome sequencing (WES) analyses were performed and were instrumental in uncovering the genetic etiology for their conditions. WES identified two novel de novo heterozygous frameshift mutations in the SMC1A gene [c.2853_2856delTCAG (p.Ser951Argfs*12) and c.3549_3552dupGGCC (p.Ile1185Glyfs*23)]. We also observed marked skewing of X-inactivation in one patient. The individual with the p.Ser951Argfs*12 mutation represents an extreme on the CdLS phenotypic spectrum, with prominent neurological involvement of severe developmental delay and refractory epilepsy, with mild craniofacial features. Both individuals eventually had incomplete clinical responses to therapy with valproic acid. We review previous reports of SMC1A mutations with epilepsy. SMC1A should be included in clinical gene panels for early infantile and early childhood epileptic encephalopathy.

Function of loud calls in wild bonobos.

Under the social origins hypothesis, human language is thought to have evolved within the framework of non-human primate social contexts and relationships. Our two closest relatives, chimpanzees and bonobos, however, have very different social relationships and this may be reflected in their use of loud calls. Much of loud calling in the male-bonded and aggressive chimpanzee functions for male alliance formation and intercommunity aggression. Bonobos, however, are female bonded and less aggressive and little is known on the use and function of their loud calls. Data on frequencies, context, and locations of vocalizations were collected for wild bonobos, Pan paniscus, at the Lomako Forest study site in the Democratic Republic of the Congo from 1983 to 2009. Both males and females participated in loud calls used for inter-party communication. Calling and response rates by both males and females were higher during party fusion than party fission and were common at evening nesting. The distribution of loud calls within the community range of loud calls was not random with males calling significantly more towards the periphery of the range and females calling significantly more in central areas. Calling and party fission were common at food patches. Responses were more frequent for female calls than for male calls. Calling, followed by fusion, was more frequent when a small party called from a large patch. We conclude that bonobo females and males loud calls can function in inter-party communication to call others to large food patches. Females call to attract potential allies and males call to attract potential mates. Our results support the social hypothesis of the origin of language because differences in the function and use of loud calls reflect the differing social systems of chimpanzees and bonobos. Bonobo loud calls are important for female communication and function in party coordination and, unlike chimpanzees, are less important in male cooperative aggression.

Bone regeneration with BMP-2 delivered from keratose scaffolds.

Infuse(®) is used clinically to promote bone repair. Its efficacy is dependent on a crosslinked collagen carrier/scaffold system that has come under scrutiny due to an inability to control BMP-2 release, which may result in unwanted outcomes such as heterotopic ossification. In this study, keratose biomaterial was evaluated as a new carrier/scaffold. Keratose was mixed with BMP-2, fabricated into a scaffold, and implanted into a critical-size rat femoral defect. This construct showed bridging as early as 4 weeks and induced trabecular morphology characteristic of a remodeling hard fracture callus at 16 weeks. Compared to the normal cortical bone, the regenerated tissue had greater volume and mineral content but less density and ultimate shear stress values. Moreover, µ-CT, biomechanics, FTIR-ATR spectroscopy, and polarized light microscopy data showed regeneration using keratose was similar to an Infuse control. However, unlike Infuse's collagen carrier system, in vitro analysis showed that BMP-2 release correlated with keratose scaffold degradation. Surprisingly, treatment with keratose only led to deposition of more bone outgrowth than the untreated negative control at the 8-week time point. The application of keratose also demonstrated a notable reduction of adipose tissues within the gap. While not able to induce osteogenesis on its own, keratose may be the first biomaterial capable of suppressing adipose tissue formation, thereby indirectly enhancing bone regeneration.

Spinal nerve ligation decreases γ-aminobutyric acidB receptors on specific populations of immunohistochemically identified neurons in L5 dorsal root ganglion of the rat.

This study examined the distribution of γ-aminobutyric acid (GABA)(B) receptors on immunohistochemically identified neurons, and levels of GABA(B(1)) and GABA(B(2)) mRNA, in the L4 and L5 dorsal root ganglia (DRG) of the rat in the absence of injury and 2 weeks after L5 spinal nerve ligation. In uninjured DRG, GABA(B(1)) immunoreactivity colocalized exclusively with the neuronal marker (NeuN) and did not colocalize with the satellite cell marker S-100. The GABA(B(1)) subunit colocalized to >97% of DRG neurons immunoreactive (IR) for neurofilament 200 (N52) or calcitonin gene-related peptide (CGRP), or labeled by isolectin B4 (IB4). Immunoreactivity for GABA(B(2)) was not detectable. L5 spinal nerve ligation did not alter the number of GABA(B(1)) -IR neurons or its colocalization pattern in the L4 DRG. However, ligation reduced the number of GABA(B(1)) -IR neurons in the L5 DRG by ≈38% compared with sham-operated and naïve rats. Specifically, ligation decreased the number of CGRP-IR neurons in the L5 DRG by 75%, but did not decrease the percent colocalization of GABA(B(1)) in those that remained. In the few IB4-positive neurons that remained in the L5 DRG, colocalization of GABA(B(1)) -IR decreased to 75%. Ligation also decreased levels of GABA(B(1)) and GABA(B(2)) mRNA in the L5, but not the L4 DRG compared with sham-operated or naïve rats. These findings indicate that the GABA(B) receptor is positioned to presynaptically modulate afferent transmission by myelinated, unmyelinated, and peptidergic afferents in the dorsal horn. Loss of GABA(B) receptors on primary afferent neurons may contribute to the development of mechanical allodynia after L5 spinal nerve ligation.

Mechanical and biological properties of keratose biomaterials.

The oxidized form of extractable human hair keratin proteins, commonly referred to as keratose, is gaining interest as a biomaterial for multiple tissue engineering studies including those directed toward peripheral nerve, spinal cord, skin, and bone regeneration. Unlike its disulfide cross-linked counterpart, kerateine, keratose does not possess a covalently cross-linked network structure and consequently displays substantially different characteristics. In order to understand its mode(s) of action and potential for clinical translatability, detailed characterization of the composition, physical properties, and biological responses of keratose biomaterials are needed. Keratose was obtained from end-cut human hair fibers by peracetic acid treatment, followed by base extraction, and subsequent dialysis. Analysis of lyophilized keratose powder determined that it contains 99% proteins by mass with amino acid content similar to human hair cortex. Metallic elements were also found in minute quantities. Protein oxidation led to disulfide bond cleavage and drastic reduction of free thiols due to conversion of sulfhydryl to sulfonic acid, chain fragmentation, and amino acid modifications. Mass spectrometry identified the major protein constituents as a heterogeneous mixture of 15 hair keratins (type I: K31-35 and K37-39, and type II: K81-86) with small amounts of epithelial keratins which exist in monomeric, dimeric, multimeric, and even degraded forms. Re-hydration with PBS enabled molecular assembly into an elastic solid-like hydrogel. Highly-porous scaffolds formed by lyophilization of the gel had the compression behavior of a cellular foam material and reverted back to gel upon wetting. Cytotoxicity assays showed that the EC50 for various cell lines were attained at 8-10 mg/mL keratose, indicating the non-toxic nature of the material. Implantation in mouse subcutaneous tissue pockets demonstrated that keratose resorption follows a rectangular hyperbolic regression with 92% degradation by an 8-week time point. Keratose was shown to integrate with the host tissue as evidenced by infiltration of leukocytes and fibroblasts, bulk material angiogenesis, and minimal fibrous encapsulation. Tissue response benchmarks were superior in keratose compared to the control PLGA 90:10 mesh. Finally, the degraded keratose was observed to remodel with the natural collagen extracellular matrix, verifying the benefit of using keratose as a temporary matrix for regenerative medicine applications.

Cardiac and pulmonary function variability in Duchenne/Becker muscular dystrophy: an initial report.

The Duchenne and Becker forms of muscular dystrophy are associated with dilated cardiomyopathy and are diseases in which pulmonary function peaks and then progressively declines. In this report, the authors quantify cardiopulmonary function variability among brothers. Brothers in 3 of 7 eligible sibships had discordant pulmonary function, with significant differences between the brothers' peak forced vital capacities and their vital capacities at last comparable age. There was no relationship between pulmonary and cardiac function among the siblings. The authors concluded that despite identical genetic mutations, cardiac and pulmonary function variability was common among brothers in their clinic with Duchenne or Becker muscular dystrophy. If confirmed by larger studies, these results have negative implications for the use of genetic testing to predict cardiopulmonary course and response to therapies in Duchenne or Becker muscular dystrophy.

Regional genomic instability predisposes to complex dystrophin gene rearrangements.

Mutations in the dystrophin gene (DMD) cause Duchenne and Becker muscular dystrophies and the majority of cases are due to DMD gene rearrangements. Despite the high incidence of these aberrations, little is known about their causative molecular mechanism(s). We examined 792 DMD/BMD clinical samples by oligonucleotide array-CGH and report on the junction sequence analysis of 15 unique deletion cases and three complex intragenic rearrangements to elucidate potential underlying mechanism(s). Furthermore, we present three cases with intergenic rearrangements involving DMD and neighboring loci. The cases with intragenic rearrangements include an inversion with flanking deleted sequences; a duplicated segment inserted in direct orientation into a deleted region; and a splicing mutation adjacent to a deletion. Bioinformatic analysis demonstrated that 7 of 12 breakpoints combined among 3 complex cases aligned with repetitive sequences, as compared to 4 of 30 breakpoints for the 15 deletion cases. Moreover, the inversion/deletion case may involve a stem-loop structure that has contributed to the initiation of this rearrangement. For the duplication/deletion and splicing mutation/deletion cases, the presence of the first mutation, either a duplication or point mutation, may have elicited the deletion events in an attempt to correct preexisting mutations. While NHEJ is one potential mechanism for these complex rearrangements, the highly complex junction sequence of the inversion/deletion case suggests the involvement of a replication-based mechanism. Our results support the notion that regional genomic instability, aided by the presence of repetitive elements, a stem-loop structure, and possibly preexisting mutations, may elicit complex rearrangements of the DMD gene.

Protein kinase A anchoring via AKAP150 is essential for TRPV1 modulation by forskolin and prostaglandin E2 in mouse sensory neurons.

Phosphorylation-dependent modulation of the vanilloid receptor TRPV1 is one of the key mechanisms mediating the hyperalgesic effects of inflammatory mediators, such as prostaglandin E(2) (PGE(2)). However, little is known about the molecular organization of the TRPV1 phosphorylation complex and specifically about scaffolding proteins that position the protein kinase A (PKA) holoenzyme proximal to TRPV1 for effective and selective regulation of the receptor. Here, we demonstrate the critical role of the A-kinase anchoring protein AKAP150 in PKA-dependent modulation of TRPV1 function in adult mouse dorsal root ganglion (DRG) neurons. We found that AKAP150 is expressed in approximately 80% of TRPV1-positive DRG neurons and is coimmunoprecipitated with the capsaicin receptor. In functional studies, PKA stimulation with forskolin markedly reduced desensitization of TRPV1. This effect was blocked by the PKA selective inhibitors KT5720 [(9S,10R,12R)-2,3,9,10,11,12-hexahydro-10-hydroxy-9-methyl-1-oxo-9,12-epoxy-1H-diindolo[1,2,3-fg:3',2',1'-kl]pyrrolo[3,4-i][1,6]benzodiazocine-10-carboxylicacid hexyl ester] and H89 (N-[2-(p-bromo-cinnamylamino)-ethyl]-5-isoquinoline-sulfon-amide 2HCl), as well as by the AKAP inhibitory peptide Ht31. Similarly, PGE(2) decreased TRPV1 desensitization in a manner sensitive to the PKA inhibitor KT5720. Both the forskolin and PGE(2) effects were strongly impaired in DRG neurons from knock-in mice that express a mutant AKAP150 lacking the PKA-binding domain (Delta36 mice). Protein kinase C-dependent sensitization of TRPV1 remained intact in Delta36 mice. The PGE(2)/PKA signaling defect in DRG neurons from Delta36 mice was rescued by overexpressing the full-length human ortholog of AKAP150 in these cells. In behavioral testing, PGE(2)-induced thermal hyperalgesia was significantly diminished in Delta36 mice. Together, these data suggest that PKA anchoring by AKAP150 is essential for the enhancement of TRPV1 function by activation of the PGE(2)/PKA signaling pathway.

Localization of the serotonergic terminal fields modulating seizures in the genetically epilepsy-prone rat.

Serotonin (5-HT) has been shown to exert antiepileptic effects in a variety of generalized convulsive seizure models, particularly the genetically epilepsy-prone rat (GEPR). The present study was designed to identify the region/site(s) where 5-HT exerts anticonvulsant effects in the GEPR-9, a model in which sound-evoked generalized tonic-clonic seizures (GTCS) are highly sensitive to manipulations in 5-HT concentration. Because the 5-HT reuptake inhibitor, fluoxetine, was known to exert anticonvulsant effects in GEPR-9s via a 5-HT-dependent mechanism, we utilized selective regional 5-HT depletion in combination with systemic fluoxetine administration to find the site where a 5-HT deficit would prevent the anticonvulsant action of fluoxetine. Widespread destruction of serotonergic terminal fields or regionally specific terminal field destruction was achieved using intracerebroventricular and more target specific infusions of 5,7-dihydroxytryptamine. The capacity of fluoxetine to suppress seizures in GEPR-9s following a loss of 5-HT was then examined. The present findings show the anticonvulsant action of fluoxetine is markedly attenuated following the loss of midbrain 5-HT, particularly in the region of the superior colliculus, while forebrain and spinal cord 5-HT do not appear to play a role in the action of fluoxetine. The importance of the deep layers of the SC was confirmed by demonstrating that direct microinfusion of fluoxetine into the SC can suppress seizures in rats pretreated with the 5-HT(1A) receptor antagonist pindolol.

Displacement of alpha-actinin from the NMDA receptor NR1 C0 domain By Ca2+/calmodulin promotes CaMKII binding.

Ca2+ influx through the N-methyl-d-aspartate (NMDA)-type glutamate receptor triggers activation and postsynaptic accumulation of Ca2+/calmodulin-dependent kinase II (CaMKII). CaMKII, calmodulin, and alpha-actinin directly bind to the short membrane proximal C0 domain of the C-terminal region of the NMDA receptor NR1 subunit. In a negative feedback loop, calmodulin mediates Ca2+-dependent inactivation of the NMDA receptor by displacing alpha-actinin from NR1 C0 upon Ca2+ influx. We show that Ca2+-depleted calmodulin and alpha-actinin simultaneously bind to NR1 C0. Upon addition of Ca2+, calmodulin dislodges alpha-actinin. Either the N- or C-terminal half of calmodulin is sufficient for Ca2+-induced displacement of alpha-actinin. Whereas alpha-actinin directly antagonizes CaMKII binding to NR1 C0, the addition of Ca2+/calmodulin shifts binding of NR1 C0 toward CaMKII by displacing alpha-actinin. Displacement of alpha-actinin results in the simultaneous binding of calmodulin and CaMKII to NR1 C0. Our results reveal an intricate mechanism whereby Ca2+ functions to govern the complex interactions between the two most prevalent signaling molecules in synaptic plasticity, the NMDA receptor and CaMKII.

Activity-driven postsynaptic translocation of CaMKII.

Ca2+ influx through the NMDA receptor and subsequent activation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) are crucial for learning and one of its physiological correlates, long-term potentiation (LTP). Ca2+/calmodulin promotes CaMKII binding to several postsynaptic proteins, including the NMDA receptor. These interactions strategically place CaMKII at locations where Ca2+ influx through the NMDA receptor is highest for further activation of CaMKII and for phosphorylation of nearby AMPA receptors and of other proteins that are important for LTP. Ca2+-dependent postsynaptic CaMKII clustering is of specific interest because LTP is synapse specific: only synapses that experience LTP-inducing high-frequency activity exhibit LTP. Ca2+-driven protein binding ensures that CaMKII accumulates only at those synapses undergoing LTP. This selectivity is economical and could contribute to the synapse specificity of LTP because downstream effects of CaMKII will occur mainly at synapses that accumulate CaMKII. In this article, we provide an overview of recent progress in postsynaptic CaMKII anchoring and discuss its implication in synaptic plasticity and the etiology and potential treatments of neurological diseases.

Brainstem seizure severity regulates forebrain seizure expression in the audiogenic kindling model.

PURPOSE: Although sound-induced (audiogenic) seizures in the genetically epilepsy-prone rat (GEPR) initially occur independent of the forebrain, repeated audiogenic seizures recruit forebrain seizure circuits in a process referred to as audiogenic kindling. In GEPR-3s, audiogenic kindling results in facial and forelimb (F&F) clonic seizures that are typical of forebrain seizures. However, in GEPR-9s, audiogenic kindling produces posttonic all-limb clonus not usually observed during forebrain seizures. We hypothesized that the more severe brainstem seizures of the GEPR-9 prevent the expression of F&F clonic seizures during audiogenic kindling. Therefore attenuation of audiogenic seizures during audiogenic kindling in GEPR-9s should allow F&F clonic seizures to be expressed. Likewise, intensifying audiogenic seizure severity in GEPR-3s should inhibit audiogenically kindled F&F clonic seizures. We have tested this hypothesis in the present study. METHODS: Lesions of the superior colliculus or treatment with low-dose phenytoin were used to suppress audiogenic seizure severity in GEPR-9s. Depletion of brain serotonin was used to increase the seizure severity in GEPR-3s. All GEPRs were then subjected to audiogenic kindling. Behavioral and electrographic seizures were assessed. RESULTS: Suppression of audiogenic seizure severity during audiogenic kindling in GEPR-9s increased the incidence forebrain seizure behavior. Kindled GEPR-9s that continued to display full tonic seizures did not exhibit forebrain convulsions, but did show posttonic clonus and forebrain seizure activity in the EEG. GEPR-3s chronically depleted of brain serotonin, along with displaying tonic brainstem seizures, tended to display less severe forebrain seizures during audiogenic kindling. CONCLUSIONS: These findings support the concept that severe brainstem seizures prevent the behavioral expression of forebrain seizures in audiogenically kindled GEPR-9s. It appears that the severe brainstem seizure of the GEPR-9 does not allow the forebrain seizure to manifest its typical behavioral concomitants despite electrographic evidence that spike-wave discharge is occurring in the forebrain.

Apo-calmodulin binds with its C-terminal domain to the N-methyl-D-aspartate receptor NR1 C0 region.

Calmodulin (CaM) is the major Ca2+ sensor in eukaryotic cells. It consists of four EF-hand Ca2+ binding motifs, two in its N-terminal domain and two in its C-terminal domain. Through a negative feedback loop, CaM inhibits Ca2+ influx through N-methyl-D-aspartate-type glutamate receptors in neurons by binding to the C0 region in the cytosolic tail of the NR1 subunit. Ca2+ -depleted (apo)CaM is pre-associated with a variety of ion channels for fast and effective regulation of channel activities upon Ca2+ influx. Using the NR1 C0 region for fluorescence and circular dichroism spectroscopy studies we found that not only Ca2+ -saturated CaM but also apoCaM bound to NR1 C0. In vitro interaction assays showed that apoCaM also binds specifically to full-length NR1 solubilized from rat brain and to the complete C terminus of the NR1 splice form that contains the C0 plus C2' domain. The Ca2+ -independent interaction of CaM was also observed with the isolated C-but not N-terminal fragment of calmodulin in the independent spectroscopic assays. Fluorescence polarization studies indicated that apoCaM associated via its C-terminal domain with NR1 C0 in an extended conformation and collapsed to adopt a more compact conformation of faster rotational mobility in its complex with NR1 C0 upon addition of Ca2+. Our results indicate that apoCaM is associated with NR1 and that the complex of CaM bound to NR1 C0 undergoes a dramatic conformational change when Ca2+ binds to CaM.

Disruption of the NMDA receptor-PSD-95 interaction in hippocampal neurons with no obvious physiological short-term effect.

PSD-95 binds to and co-localizes with NMDA receptors at postsynaptic sites. Their co-expression in COS7 cells induces the formation of aggregates containing both proteins. These findings have lead to the hypothesis that PSD-95 helps to cluster NMDA receptors at postsynaptic sites. In addition, PSD-95 binds various regulatory proteins including Src, Pyk2, SynGAP, and nNOS and may recruit signaling proteins to NMDA receptors. We tested whether synaptic transmission or plasticity was affected by acute dissociation of the PSD-95-NMDA receptor interaction with various peptides that bound to the first two PDZ domains of PSD-95 and its homologs and with antibodies directed against the very C-terminus of the NR2A and NR2B subunits of the NMDA receptor. Membrane-impermeable peptides injected via whole cell patch electrodes distributed within minutes throughout dendritic branches into spines in acute hippocampal slices and membrane-permeable peptides containing 11 arginine residues effectively accumulated in neurites in slices and primary hippocampal cultures. Neither peptides nor antibodies showed any effect on basal synaptic transmission or induction of long-term potentiation (LTP) in hippocampal slices. Pharmacologically isolated NMDA receptor activity was also not affected. However, the membrane-permeable peptide disrupted the NMDA receptor-PSD-95 interaction in slices as tested by immunoprecipitation and subsequent immunoblotting. These findings suggest that acute dissociation of PSD-95 and its homologs from the NMDA receptor and likely from other protein complexes does not result in any easily detectable physiological effects in hippocampal slices. However, we cannot exclude a role of PSD-95 in early events that lead to clustering of NMDA receptors or of other proteins including stargazin and AMPA receptors at postsynaptic sites nor do these experiments address the possibility of long-term changes in the slices. In fact, incubation of primary hippocampal cultures with the membrane-permeable peptide lead to a moderate decrease in the number of dendritic clusters of PSD-95 and NMDA receptors and their colocalization by 20-30%, suggesting some role of PSD-95 and its homologs in NMDA receptor clustering.

Role of the superior colliculus and the intercollicular nucleus in the brainstem seizure circuitry of the genetically epilepsy-prone rat.

PURPOSE: The neuronal network responsible for the convulsive behavior associated with sound-induced seizures in genetically epilepsy-prone rats (GEPRs) is believed to include the inferior colliculus and other brainstem structures such as the deep layers of the superior colliculus (DLSC), periaqueductal gray, and pontine reticular formation. However, previous studies also suggested that the DLSC and the nearby intercollicular nucleus (ICN) are part of a midbrain anticonvulsant zone capable of suppressing tonic convulsions when activated with bicuculline. Our aim in this study was to investigate the role of the superior colliculus (SC) and the ICN in generalized tonic-clonic seizures (GTCSs). METHODS: Bilateral lesions of the SC and the ICN as well as bicuculline infusions into the ICN were used to assess the role of this dorsal midbrain region in brainstem seizures induced by sound stimulation in GEPR-9s and GEPR-3s. RESULTS: Lesions of the SC markedly attenuated audiogenic seizure (AGS) severity by abolishing all behavioral components except the wild running. Lesions of the ICN significantly reduced seizure severity in GEPR-9s, but were somewhat less effective than SC lesions. Bicuculline infusion into the deep layers of the SC and/or the ICN produced audiogenic-like seizures in GEPR-9s. CONCLUSIONS: These findings support the hypothesis that the SC and ICN are important components of the brainstem seizure network, but suggest they are not necessary for the wild-running component of the seizure. The results further indicate that stimulation of the tectum facilitates GTCSs. Thus these findings suggest that the dorsal midbrain, when stimulated, is proconvulsant rather than anticonvulsant regarding brainstem seizures in GEPRs.

Orangutan cultures and the evolution of material culture.

Geographic variation in some aspects of chimpanzee behavior has been interpreted as evidence for culture. Here we document similar geographic variation in orangutan behaviors. Moreover, as expected under a cultural interpretation, we find a correlation between geographic distance and cultural difference, a correlation between the abundance of opportunities for social learning and the size of the local cultural repertoire, and no effect of habitat on the content of culture. Hence, great-ape cultures exist, and may have done so for at least 14 million years.