Cortical Thickness Changes Associated with Photoparoxysmal Response

Photoparoxysmal response (PPR) is an EEG trait of spike and spike-wave discharges in response to photic stimulation that is closely linked to idiopathic generalized epilepsy (IGE). In our previous studies we showed that PPR is associated with functional alterations in the occipital and frontal cortices. The aim of the present study was to determine structural changes associated with PPR. For this purpose we analysed the cortical thickness as derived from T1 MRI images in PPR-positive-subjects (n = 12; 15.5 ± 8.6 years; 4 males), PPR-positive-IGE-patients (n = 12; 14.9 ± 2.7 years; 4 males) and compared these groups with a group of PPR-negative-healthy-controls (HC, n = 17; 15.3 ± 3.6 years; 6 males). Our results revealed an increase of cortical thickness in the occipital, frontal and parietal cortices bilaterally in PPR-positive-subjects in comparison to HC. Moreover PPR-positive-subjects presented a significant decrease of cortical thickness in the temporal cortex in the same group contrast. IGE patients exhibited lower cortical thickness in the temporal lobe bilaterally and in the right paracentral region in comparison to PPR-positive-subjects. Our study demonstrates structural changes in the occipital lobe, frontoparietal regions and temporal lobe, which also show functional changes associated with PPR. Patients with epilepsy present changes in the temporal lobe and supplementary motor area.     

Linked selection and recombination rate variation drive the evolution of the genomic landscape of differentiation across the speciation continuum of Ficedula flycatchers

Speciation is a continuous process during which genetic changes gradually accumulate in the genomes of diverging species. Recent studies have documented highly heterogeneous differentiation landscapes, with distinct regions of elevated differentiation (“differentiation islands”) widespread across genomes. However, it remains unclear which processes drive the evolution of differentiation islands; how the differentiation landscape evolves as speciation advances; and ultimately, how differentiation islands are related to speciation. Here, we addressed these questions based on population genetic analyses of 200 resequenced genomes from 10 populations of four Ficedula flycatcher sister species. We show that a heterogeneous differentiation landscape starts emerging among populations within species, and differentiation islands evolve recurrently in the very same genomic regions among independent lineages. Contrary to expectations from models that interpret differentiation islands as genomic regions involved in reproductive isolation that are shielded from gene flow, patterns of sequence divergence (d_xy and relative node depth) do not support a major role of gene flow in the evolution of the differentiation landscape in these species. Instead, as predicted by models of linked selection, genome-wide variation in diversity and differentiation can be explained by variation in recombination rate and the density of targets for selection. We thus conclude that the heterogeneous landscape of differentiation in Ficedula flycatchers evolves mainly as the result of background selection and selective sweeps in genomic regions of low recombination. Our results emphasize the necessity of incorporating linked selection as a null model to identify genome regions involved in adaptation and speciation.Uncovering the genetic architecture of reproductive isolation and its evolutionary history are central tasks in evolutionary biology. The identification of genome regions that are highly differentiated between closely related species, and thereby constitute candidate regions involved in reproductive isolation, has recently been a major focus of speciation genetic research. Studies from a broad taxonomic range, involving organisms as diverse as plants (Renaut et al. 2013), insects (Turner et al. 2005; Lawniczak et al. 2010; Nadeau et al. 2012; Soria-Carrasco et al. 2014), fishes (Jones et al. 2012), mammals (Harr 2006), and birds (Ellegren et al. 2012) contribute to the emerging picture of a genomic landscape of differentiation that is usually highly heterogeneous, with regions of locally elevated differentiation (“differentiation islands”) widely spread over the genome. However, the evolutionary processes driving the evolution of the differentiation landscape and the role of differentiation islands in speciation are subject to controversy (Turner and Hahn 2010; Cruickshank and Hahn 2014; Pennisi 2014).Differentiation islands were originally interpreted as “speciation islands,” regions that harbor genetic variants involved in reproductive isolation and are shielded from gene flow by selection (Turner et al. 2005; Soria-Carrasco et al. 2014). During speciation-with-gene-flow, speciation islands were suggested to evolve through selective sweeps of locally adapted variants and by hitchhiking of physically linked neutral variation (“divergence hitchhiking”) (Via and West 2008); gene flow would keep differentiation in the remainder of the genome at bay (Nosil 2008; Nosil et al. 2008). In a similar way, speciation islands can arise by allopatric speciation followed by secondary contact. In this case, genome-wide differentiation increases during periods of geographic isolation, but upon secondary contact, it is reduced by gene flow in genome regions not involved in reproductive isolation. In the absence of gene flow in allopatry, speciation islands need not (but can) evolve by local adaptation, but may consist of intrinsic incompatibilities sensu Bateson-Dobzhansky-Muller (Bateson 1909; Dobzhansky 1937; Muller 1940) that accumulated in spatially isolated populations.However, whether differentiation islands represent speciation islands has been questioned. Rather than being a cause of speciation, differentiation islands might evolve only after the onset of reproductive isolation as a consequence of locally accelerated lineage sorting (Noor and Bennett 2009; Turner and Hahn 2010; White et al. 2010; Cruickshank and Hahn 2014; Renaut et al. 2014), such as in regions of low recombination (Nachman 2002; Sella et al. 2009; Cutter and Payseur 2013). In these regions, the diversity-reducing effects of both positive selection and purifying selection (background selection [BGS]) at linked sites (“linked selection”) impact physically larger regions due to the stronger linkage among sites. The thereby locally reduced effective population size (N_e) will enhance genetic drift and hence inevitably lead to increased differentiation among populations and species.These alternative models for the evolution of a heterogeneous genomic landscape of differentiation are not mutually exclusive, and their population genetic footprints can be difficult to discern. In the cases of (primary) speciation-with-gene-flow and gene flow at secondary contact, shared variation outside differentiation islands partly stems from gene flow. In contrast, under linked selection, ancestral variation is reduced and differentiation elevated in regions of low recombination, while the remainder of the genome may still share considerable amounts of ancestral genetic variation and show limited differentiation. Many commonly used population genetic statistics do not capture these different origins of shared genetic variation and have the same qualitative expectations under both models, such as reduced diversity (π) and skews toward an excess of rare variants (e.g., lower Tajima''s D) in differentiation islands relative to the remainder of the genome. However, since speciation islands should evolve by the prevention or breakdown of differentiation by gene flow in regions not involved in reproductive isolation, substantial gene flow should be detectable in these regions (Cruickshank and Hahn 2014) and manifested in the form of reduced sequence divergence (d_xy) or as an excess of shared derived alleles in cases of asymmetrical gene flow (Patterson et al. 2012). Under linked selection, predictions are opposite for d_xy (Cruickshank and Hahn 2014), owing to reduced ancestral diversity in low-recombination regions. Further predictions for linked selection include positive and negative relationships of recombination rate with genetic diversity (π) and differentiation (F_ST), respectively, and inverse correlations of the latter two with the density of targets for selection. Finally, important insights into the nature of differentiation islands may be gained by studying the evolution of differentiation landscapes across the speciation continuum. Theoretical models and simulations of speciation-with-gene-flow predict that after an initial phase during which differentiation establishes in regions involved in adaptation, differentiation should start spreading from these regions across the entire genome (Feder et al. 2012, 2014; Flaxman et al. 2013).Unravelling the processes driving the evolution of the genomic landscape of differentiation, and hence understanding how genome differentiation unfolds as speciation advances, requires genome-wide data at multiple stages of the speciation continuum and in a range of geographical settings from allopatry to sympatry (Seehausen et al. 2014). Although studies of the speciation continuum are emerging (Hendry et al. 2009; Kronforst et al. 2013; Shaw and Mullen 2014, and references therein), empirical examples of genome differentiation at multiple levels of species divergence remain scarce (Andrew and Rieseberg 2013; Kronforst et al. 2013; Martin et al. 2013), and to our knowledge, have so far not jointly addressed the predictions of alternative models for the evolution of the genomic landscape of differentiation. In the present study, we implemented such a study design encompassing multiple populations of four black-and-white flycatcher sister species of the genus Ficedula (Fig. 1A,B; Supplemental Fig. S1; for a comprehensive reconstruction of the species tree, see Nater et al. 2015). Previous analyses in collared flycatcher (F. albicollis) and pied flycatcher (F. hypoleuca) revealed a highly heterogeneous differentiation landscape across the genome (Ellegren et al. 2012). An involvement of gene flow in its evolution would be plausible, as hybrids between these species occur at low frequencies in sympatric populations in eastern Central Europe and on the Baltic Islands of Gotland and Öland (Alatalo et al. 1990; Sætre et al. 1999), although a recent study based on genome-wide markers identified no hybrids beyond the F₁ generation (Kawakami et al. 2014a). Still, gene flow from pied into collared flycatcher appears to have occurred (Borge et al. 2005; Backström et al. 2013; Nadachowska-Brzyska et al. 2013) despite premating isolation (for review, see Sætre and Sæther 2010), hybrid female sterility (Alatalo et al. 1990; Tegelström and Gelter 1990), and strongly reduced long-term fitness of hybrid males (Wiley et al. 2009). Atlas flycatcher (F. speculigera) and semicollared flycatcher (F. semitorquata) are two closely related species, which have been less studied, but may provide interesting insights into how genome differentiation evolves over time. Here, we take advantage of this system to identify the processes underlying the evolution of differentiation islands based on the population genetic analysis of whole-genome resequencing data of 200 flycatchers.Open in a separate windowFigure 1.A recurrently evolving genomic landscape of differentiation across the speciation continuum in Ficedula flycatchers. (A) Species’ neighbor-joining tree based on mean genome-wide net sequence divergence (d_A). The same species tree topology was inferred with 100% bootstrap support from the distribution of gene trees under the multispecies coalescent (Supplemental Fig. S1). (B) Map showing the locations of population sampling and approximate species ranges. (C) Population genomic parameters along an example chromosome (Chromosome 4A) (see Supplemental Figs. S2, S4 for all chromosomes). Color codes for specific–specific parameters: (blue) collared; (green) pied; (orange) Atlas; (red) semicollared. Color codes for d_xy: (green) collared-pied; (light blue) collared-Atlas; (blue) collared-semicollared; (orange) pied-Atlas; (red) pied-semicollared; (black) Atlas-semicollared. For differentiation within species, comparisons with the Italian (collared) and Spanish (pied) populations are shown. Color codes for F_ST within collared flycatchers: (cyan) Italy–Hungary; (light blue) Italy–Czech Republic; (dark blue) Italy–Baltic. Color codes for F_ST within pied flycatchers: (light green) Spain–Sweden; (green) Spain–Czech Republic; (dark green) Spain–Baltic. (D) Distributions of differentiation (F_ST) from collared flycatcher along the speciation continuum. Distributions are given separately for three autosomal recombination percentiles (33%; 33%–66%; 66%–100%) corresponding to high (>3.4 cM/Mb, blue), intermediate (1.3–3.4 cM/Mb, orange), and low recombination rate (0–1.3 cM/Mb, red), and the Z Chromosome (green). Geographically close within-species comparison: Italy–Hungary. Comparisons within species include the geographically close Italian and Hungarian populations (within [close]), and the geographically distant Italian and Baltic populations (within [far]). Geographically far within-species comparison: Italy–Baltic. (E) Differentiation from collared flycatcher along an example chromosome (Chromosome 11) (see Supplemental Fig. S3 for all chromosomes). Color codes for between-species comparisons: (green) pied; (orange) Atlas; (red) semicollared; (dark red) red-breasted; (black) snowy-browed flycatcher. Color codes for within-species comparisons: (cyan) Italy–Hungary; (blue) Italy–Baltic. Flycatcher artwork in panel A courtesy of Dan Zetterström.     

WAA apheresis registry in the Czech Republic: Two centers experience

Introduction

Hemaphereses are sophisticated procedures performed for many indications even in severely ill patients. Many authors consider quite necessary to register as many details as possible of treatments with therapeutic apheresis. WAA meets the requirement to compare data with centers not performing apheresis for the same diagnosis. In Czech Republic hemaphereses are used in a broad spectrum of indications. Since the year 2004 data on hemaphereses done in Czech Republic have been registered. In this paper we present a survey of our to date recordings.

Patients and methods

Data of performed therapeutic hemaphereses (plasma exchange, erythrocytapheresis, leukapheresis, thrombocytapheresis, photopheresis, immunopheresis, and rheopheresis) have been entered in WAA registry with many details. We have been evaluated 1289 procedures in 216 patients done in our two centers (center I, center II).

Results

Center I registered 129 procedures in 41 patients, center II 1260 procedures in 175 patients. The patients are divided according to centers specialization (center II has registered 12 long-term treated patients with LDL-apheresis; mean time of therapy 7.1 years and a median of 34 procedures/patient. Side-effects registered in center I and center II were 3.1% and 5.6% of the procedures, respectively. Most frequent side-effects were citrate toxicity, neurovegetative lability, problems with venous access and hypotension. All were easy to treat, no serious events or death occurred.

Conclusions

In Czech Republic hemaphereses are performed in a broad scale of indications and now it is nearly 5 years that data are registered in our two university centers. In 2004 we entered WAA registry because it meets the requirement to compare data with centers that do not perform aphereses for the same diagnosis. This comparison would certainly improve efficacy of the hemapheresis therapy even further. To enter WAA registry is easy, at no expense and without any problems.     

Autoantibodies to vasoactive peptides and angiotensin converting enzyme in patients with systemic diseases of the connective tissue

AIM: To estimate the level of natural autoantibodies (NAAb) to angiotensin-converting enzyme (ACE) and endogenic mediators affecting vascular tone (bradykinin--BK, angiotensin II--AII, vasopressin--VP) as well as the activity of serum ACE in patients with systemic diseases of the connective tissue. MATERIAL AND METHODS: Levels of NAAb were measured by enzyme immunoassay in sera from 30 patients with SLE, 19 patients with rheumatoid arthritis (RA) and 36 patients with scleroderma systematica (SS). Serum from donors served control. IgM NAAb to ACE were measured by a new technique. Serum ACE activity was determined by the initial velocity of hydrolysis reaction using spectrofluometry. RESULTS: IgM NAAb were detected in the sera of both patients and donors. SS patients had the level of NAAb to ACE in diffuse form significantly higher than in limited (p < 0.05). In SLE and SS patients ACE activity was significantly lower (p < 0.05) than in healthy subjects and RA patients. Levels of NAAb to BK was significantly elevated (p < 0.01) in patients with SLE and RA vs donors while to AII in SS patients it was lowered (p < 0.001). Patients with diffuse SS had NAAb to BK higher than patients with SS limited form (p < 0.01). In SLE the lowest levels of NAAb to all the mediators studied were observed in patients with nephritis, for NAAb to VP the differences were significant (p < 0.05). In patients with urinary syndrome concentration of NAAb to BK was significantly higher (p < 0.01), differences between their levels in patients with nephritis and urinary syndrome were also significant (p < 0.05). CONCLUSION: Further studies are needed for specification of physiological or pathological role of NAAb to endogenic mediators.     

Buried bumper syndrome:A complication of percutaneous endoscopic gastrostomy

Percutaneous endoscopic gastrostomy(PEG) is a widely used method of nutrition delivery for patients with longterm insufficiency of oral intake. The PEG complication rate varies from 0.4% to 22.5% of cases, with minor complications being three times more frequent. Buried bumper syndrome(BBS) is a severe complication of this method, in which the internal fixation device migrates alongside the tract of the stoma outside the stomach. Excessive compression of tissue between the external and internal fixation device of the gastrostomy tube is considered the main etiological factor leading to BBS. Incidence of BBS is estimated at around 1%(0.3%-2.4%). Inability to insert, loss of patency and leakage around the PEG tube are considered to be a typical symptomatic triad. Gastroscopy is indicated in all cases in which BBS is suspected. The depth of disc migration in relation to the lamina muscularis propria of the stomach is critical for further therapy and can be estimated by endoscopic or transabdominal ultrasound. BBS can be complicated by gastrointestinal bleeding, perforation, peritonitis, intra-abdominal and abdominal wall abscesses, or phlegmon, and these complications can lead to fatal outcomes. The most important preventive measure is adequate positioning of the external bolster. A conservative approach should be applied only in patients with high operative risk and dismal prognosis. Choice of the method of release is based on the type of the PEG set and depth of disc migration. A disc retained inside the stomach and completely covered by the overgrowing tissue can be released using some type of endoscopic dissection technique(needle knife, argon plasma coagulation, or papillotome through the cannula). Proper patient selection and dissection of the overgrowing tissue are the major determinants for successful endoscopic therapy. A disc localized out of the stomach(lamina muscularis propria) should be treated by a surgeon.     

Quantitative myotonia assessment with a commercially available dynamometer in myotonic dystrophy types 1 and 2

Introduction: The objective of this study was to develop a simple method for quantitative assessment of myotonia in patients with myotonic dystrophy type 1 (DM1) and DM2, to compare the myotonia severity, and to correlate this objective outcome with a subjective scale, the Myotonia Behaviour Scale (MBS). Methods: A commercially available dynamometer was used for all measurements. The relaxation time after voluntary contraction was measured in 20 patients with DM1, 25 patients with DM2, and 35 healthy controls. Results: The average relaxation time was 0.17 s in controls, 2.96 s in patients with DM1, and 0.4 s in patients with DM2. The correlation between relaxation time and MBS score was significant, 0.627 in patients with DM1 and 0.581 in patients with DM2. Discussion: Our method provides a valid and reliable quantitative measure of grip myotonia suitable as an outcome measure in clinical trials and as part of routine examinations to gather data on the natural history of myotonic disorders. Muscle Nerve 59:431–435, 2019     

Pre-implantation Genetic Diagnosis: The Road Forward in Canada

The use of pre-implantation genetic diagnosis (PGD) is increasing as the list of indications it can test for constantly expands. This raises new challenges for clinicians and prospective parents regarding possible uses and calls for guidance. Policy approaches towards PGD vary greatly worldwide. The 2004 Canadian Assisted Human Reproduction Act does not provide guidance, except for prohibiting non-medical sex selection. Criminal legislation is an unsuitable policy instrument to regulate human genetics and reproductive medicine. We call for professional societies to issue guidelines regarding the uses of PGD that would establish the standard of care and legal norms. Such guidelines should be based on a patient-centered approach and respect individual autonomy in reproductive decision-making. Canadian approaches to PGD should also consider issues related to equity of access. Moreover, since PGD often raises concerns about eugenic uses, guidelines should also consider its societal impact and its implementation should be accompanied by policies that maintain or increase social support for people with disabilities. Finally, public engagement could provide an evidence-base regarding Canadian societal values and concerns that should guide regulatory reform, for example, the regulation of non-medical sex selection through PGD.     

Does endoscopic puncture of ureterocele provide not only an initial solution,but also a definitive treatment in all children? Over the 26 years of experience

Purpose

We have retrospectively evaluated all patients who underwent endoscopic puncture (EP) of ureterocele over the last 26 years with special reference to the need in the second intervention and disease-free status.

Methods

78 (69%) of the 112 patients following EP and completed follow-up were included. 51 (65%) were diagnosed prenatally and 27 (35%) postnatally. 46 patients (60%) had intravesical, while 32 (40%) had ectopic ureterocele. Median age at time of puncture was 4 months. Median time of the follow-up was 12 years (range 1–26 years), while 23 (30%) followed over 10 years and 15 (19%) completed adolescent period.

Results

Four children with ectopic ureterocele required secondary puncture. Ectopic ureterocele children had significantly more postoperative UTIs (13 (40%) ectopic vs 4 (19%) intravesical p?=?0.047). 19 RRUs (44%) showed spontaneous resolution of VUR. 14 (18%) children required additional surgery: 7, endoscopic correction of VUR; 3, ureteral reimplantation and 4, partial nephrectomy. The need for additional surgery following puncture was higher in the group of children with ectopic ureterocele; however, this difference did not reach a statistical significance (p?=?0.716).

Conclusions

Our data show that EP of ureterocele is a durable and long-term effective procedure in vast majority of the children.