Short- and intermediate-interval cortical inhibition and facilitation assessed by navigated transcranial magnetic stimulation

One of the most widely utilized in vitro models of ischemia or oxygen glucose deprivation (OGD) is the hippocampal organotypical culture (HOTC). The HOTC is used not only for the study of the mechanisms of cell death, but also has been the cornerstone of synaptic physiology. Although the intact nature of the HOTC is one of its primary advantages, some studies require a dissociated preparation in order to distinguish cell type specific responses. Typically, primary dissociated neuronal cultures are prepared from embryonic tissue. Since the HOTC is prepared from postnatal pups, we wanted to establish a primary culture of hippocampus from postnatal pups to parallel our studies in the HOTC preparation. Mixed cultures were prepared by enzymatic dissociation of hippocampus from 7-day-old mouse pups. These cultures responded to OGD with a time course of delayed cell death that was similar to that reported in HOTC. Dual label immunocytochemical staining revealed that neurons, but not astrocytes, were dying from apoptosis following OGD. To examine this vulnerability further, we also prepared neuronal enriched cultures by treating mixed cultures with cytosine-β-d-arabinofuranoside (CBA). These neuronal cultures appear to be even more sensitive to OGD. In addition, we have established primary astrocyte-enriched cultures from the same age pups to examine the vulnerability of astrocytes to OGD. These three culture preparations are useful for comparison of the responses of the two major cell types in the same culture, and the enriched cultures will allow biochemical, electrophysiological and molecular studies of homogenous cell populations.     

Motor cortical plasticity is impaired in Unverricht–Lundborg disease

Patients with Unverricht–Lundborg disease, also referred to as progressive myoclonus epilepsy type 1, exhibit widespread motor symptoms and signs in addition to epileptic seizures, which suggest abnormal excitability of the primary motor pathways. To explore the plasticity of the sensory–motor cortex, we employed a modern neurophysiological method, the paired associative stimulation protocol, which resembles the concept of long‐term potentiation of experimental studies. Seven patients with genetically verified Unverricht–Lundborg disease and 13 healthy control subjects were enrolled in the study to characterize cortical sensory–motor plasticity. In the study protocol, peripheral electric median nerve stimulation preceded navigated transcranial magnetic stimulation targeted to the representation area of thenar musculature on the contralateral primary motor cortex. The protocol consisted of 132 transcranial magnetic stimulation trials at 0.2 Hz, preceded by peripheral sensory stimulation at 25 ms. Motor‐evoked potential amplitudes were analyzed at baseline and after the paired associative stimulation protocol at an intensity of 130% of the individual motor threshold. The patients with Unverricht–Lundborg disease exhibited an average decrease of 15% in motor‐evoked potential amplitudes 30 minutes after paired associative stimulation, whereas in the control subjects, a significant increase (101%) was observed (P < .05), as expected. The results indicate a lack of normal cortical plasticity in Unverricht–Lundborg disease, which stresses the role of abnormal motor cortical functions or sensorimotor integration as possible pathophysiological contributors to the motor symptoms. The impaired cortical plasticity may be associated with the previously reported structural and physiological abnormalities of the primary motor cortex. © 2011 Movement Disorder Society     

activated polyamine catabolism in acute pancreatitis: alpha-methylated polyamine analogues prevent trypsinogen activation and pancreatitis-associated mortality

Polyamines are essential for normal cellular growth and function. Activation of polyamine catabolism in transgenic rats overexpressing spermidine/spermine N(1)-acetyltransferase, the key enzyme in polyamine catabolism, results in severe acute pancreatitis. Here, we investigated the role of polyamine catabolism in pancreatitis and studied the effect of polyamine analogues on the outcome of the disease. Polyamine depletion was associated with arginine- and cerulein-induced pancreatitis as well as with human acute necrotizing and chronic secondary pancreatitis. Substitution of depleted polyamine pools with methylspermidine partially prevented arginine-induced necrotizing pancreatitis whereas cerulein-induced edematous pancreatitis remained unaffected. Transgenic rats receiving methylated polyamine analogues after the induction of pancreatitis showed less pancreatic damage than the untreated rats. Most importantly, polyamine analogues dramatically rescued the animals from pancreatitis-associated mortality. Induction of spermidine/spermine N(1)-acetyltransferase in acinar cells isolated from transgenic rats resulted in increased trypsinogen activation. Pretreatment of acini with bismethylspermine prevented trypsinogen activation, indicating that premature proteolytic activation is one of the effects triggered by polyamine depletion. Our data suggest that activation of polyamine catabolism is a general pathway in the pathogenesis of acute pancreatitis and that experimental disease can be ameliorated with stable polyamine analogues.     

Methylation of H19 and its imprinted control region (H19 ICR1) in Müllerian aplasia

Severe hypomethylation of the H19 imprinted control region (ICR1) in two patients with Silver-Russell syndrome (SRS) who have genital malformations has encouraged us to study DNA methylation in a cohort of 83 patients with Müllerian aplasia (MA). Site-specific methylation analyses of H19 ICR1 by quantitative real-time polymerase chain reaction in 80 clinically well-diagnosed Finnish MA patients showed no association between hypomethylation and the MA phenotype, but studies of the H19 locus in 38 patients showed aberrant methylation in 3/16 studied sites.     

Acute toxicity and outcome among pediatric allogeneic hematopoietic transplant patients conditioned with treosulfan-based regimens

Abstract

Treosulfan-based regimens constitute a feasible and increasingly used, but still myeloablative, conditioning in pediatric allogeneic hematopoietic stem cell transplantation (HSCT). We retrospectively analyzed the acute toxicity and outcome of all consecutive (2004–2015) pediatric HSCT patients prepared for HSCT with treosulfan in a single-center setting. We included HSCTs performed for both nonmalignant (n?=?23) and malignant diseases (n?=?11). The controls were patients with nonmalignant diseases or hematological malignancies conditioned with cyclophosphamide (Cy)-total body irradiation (TBI)-based (39 patients) or busulfan-based regimens (11 patients). The major toxicities of the treosulfan-based regimens were limited to oral mucosa and skin. 50% of the patients needed IV morphine for severe mucositis compared to 31% in patients conditioned with Cy-TBI (P?=?0.02). Other toxicities were rare. The disease-free survival (DFS) of patients transplanted for nonmalignant disorders was 88.9?±?7.5% at 2?years. The event-free survival (EFS) at 2?years in this small cohort for those with a malignant disease and a treosulfan-based conditioning was 54.5?±?1.5%. We conclude that a treosulfan-based conditioning regimen gives excellent DFS in pediatric HSCT performed for a nonmalignant disorder but with substantial mucosal toxicity. In a malignant disorder a treosulfan-based regimen looks promising but larger, preferably randomized, studies are needed to prove efficacy.     

Rare missense mutations in RECQL and POLG associate with inherited predisposition to breast cancer

Several known breast cancer susceptibility genes with moderate‐to‐high risk alleles encode proteins involved in DNA damage response (DDR). As these explain less than half of the hereditary breast cancer cases, additional predisposing alleles are likely to be discovered. Many of the previous studies utilizing massive parallel sequencing have focused on the protein‐truncating variants, and the role of rare missense mutations has remained poorly addressed. To identify novel susceptibility factors, we have systematically analyzed the data from our parallel sequencing of 796 DDR genes in 189 Northern Finnish hereditary breast cancer patients for rare missense variants, predicted as deleterious. Thirty‐five variants were studied here for the disease association using Finnish breast cancer case (n = 492–2,035) and control (n = 277–1,539) cohorts. As a result, two missense variants in genes involved in DNA replication, RECQL p.I156M and POLG p.L392V, the former involving genomic and the latter mitochondrial DNA replication, showed significant association with risk of breast cancer. Rare RECQL p.I156M allele was observed in breast cancer cases only (6/1,946, 0.3%, p = 0.043), whereas POLG p.L392V was two times more frequent in breast cancer cases (53/2,238, 2.4%) compared to controls (18/1,539, 1.2%, OR = 2.1, 95% CI 1.2–3.5, p = 0.010). Based on the current genetic data, both RECQL p.I156M and POLG p.L392V represent novel breast cancer predisposing alleles.     

11q13 is a susceptibility locus for hormone receptor positive breast cancer

A recent two-stage genome-wide association study (GWAS) identified five novel breast cancer susceptibility loci on chromosomes 9, 10, and 11. To provide more reliable estimates of the relative risk associated with these loci and investigate possible heterogeneity by subtype of breast cancer, we genotyped the variants rs2380205, rs1011970, rs704010, rs614367, and rs10995190 in 39 studies from the Breast Cancer Association Consortium (BCAC), involving 49,608 cases and 48,772 controls of predominantly European ancestry. Four of the variants showed clear evidence of association (P ≤ 3 × 10(-9) ) and weak evidence was observed for rs2380205 (P = 0.06). The strongest evidence was obtained for rs614367, located on 11q13 (per-allele odds ratio 1.21, P = 4 × 10(-39) ). The association for rs614367 was specific to estrogen receptor (ER)-positive disease and strongest for ER plus progesterone receptor (PR)-positive breast cancer, whereas the associations for the other three loci did not differ by tumor subtype.