A gene transfer agent and a dynamic repertoire of secretion systems hold the keys to the explosive radiation of the emerging pathogen Bartonella.

Gene transfer agents (GTAs) randomly transfer short fragments of a bacterial genome. A novel putative GTA was recently discovered in the mouse-infecting bacterium Bartonella grahamii. Although GTAs are widespread in phylogenetically diverse bacteria, their role in evolution is largely unknown. Here, we present a comparative analysis of 16 Bartonella genomes ranging from 1.4 to 2.6 Mb in size, including six novel genomes from Bartonella isolated from a cow, two moose, two dogs, and a kangaroo. A phylogenetic tree inferred from 428 orthologous core genes indicates that the deadly human pathogen B. bacilliformis is related to the ruminant-adapted clade, rather than being the earliest diverging species in the genus as previously thought. A gene flux analysis identified 12 genes for a GTA and a phage-derived origin of replication as the most conserved innovations. These are located in a region of a few hundred kb that also contains 8 insertions of gene clusters for type III, IV, and V secretion systems, and genes for putatively secreted molecules such as cholera-like toxins. The phylogenies indicate a recent transfer of seven genes in the virB gene cluster for a type IV secretion system from a cat-adapted B. henselae to a dog-adapted B. vinsonii strain. We show that the B. henselae GTA is functional and can transfer genes in vitro. We suggest that the maintenance of the GTA is driven by selection to increase the likelihood of horizontal gene transfer and argue that this process is beneficial at the population level, by facilitating adaptive evolution of the host-adaptation systems and thereby expansion of the host range size. The process counters gene loss and forces all cells to contribute to the production of the GTA and the secreted molecules. The results advance our understanding of the role that GTAs play for the evolution of bacterial genomes.

Subclinical epileptiform activity in children with electrical status epilepticus during sleep: effects on cognition and behavior before and after treatment with levetiracetam.

We performed a double-blind placebo-controlled crossover study of the effects of spike activity during sleep and when awake on learning, long-term memory, vigilance and behavior before and after treatment with levetiracetam in children with electrical status epilepticus during sleep. At baseline, verbal learning declined with increasing spike activity, but there were no relations between spike activity and memory, vigilance or behavior. Levetiracetam was effective in reducing sleep-related spike activity, but on a group level, this had no clear effects on behavior, vigilance or learning and memory. Our results do not allow firm conclusions whether to treat nocturnal epileptiform activity or not; larger samples and longer follow-up may be needed.

The effect of levetiracetam on focal nocturnal epileptiform activity during sleep--a placebo-controlled double-blind cross-over study.

Electric Status Epilepticus during Sleep (ESES) occurs in children with and without epilepsy. It may be related to disturbances as autism spectrum disorder, attention-deficit hyperactivity disorder and acquired aphasia (Landau-Kleffner syndrome). Antiepileptic drug (AED) treatment has been reported in small studies without placebo control. This study was designed to assess AED effect in a placebo-controlled double-blind cross-over study. Levetiracetam (LEV) was chosen based on clinical evidence. Eighteen patients fulfilled the inclusion criteria. The mean spike index at baseline was 56, falling to a mean of 37 at the end of the LEV treatment period. Assessed with a 2-way ANOVA, there is a significant treatment effect (p<0.0002). To the best of our knowledge, this is the first placebo-controlled double-blind cross-over study for any AED in patients with ESES. The effect of LEV is comparable with its effect in treatment of epileptic seizures.

Levetiracetam reduces the frequency of interictal epileptiform discharges during NREM sleep in children with ADHD.

BACKGROUND: Symptoms of attention deficit hyperactivity disorder (ADHD) are more common in children with epilepsy than in the general paediatric population. Epileptiform discharges in EEG may be seen in children with ADHD also in those without seizure disorders. Sleep enhances these discharges which may be suppressed by levetiracetam. AIM: To assess the effect of levetiracetam on focal epileptiform discharges during sleep in children with ADHD. METHOD: In this retrospective study a new semi-automatic quantitative method based on the calculation of spike index in 24-h ambulatory EEG recordings was applied. Thirty-five ADHD children, 17 with focal epilepsy, one with generalised epilepsy, and 17 with no seizure disorder were evaluated. Follow-up 24-h EEG recordings were performed after a median time of four months. RESULTS: Mean spike index was 50 prior to levetiracetam treatment and 21 during treatment. Seventeen children had no focal interictal epileptiform discharges in EEG at follow-up. Five children had a more than 50% reduction in spike index. Thus, a more than 50% reduction in spike index was found in 22/35 children (63%). Out of these an improved behaviour was noticed in 13 children (59%). CONCLUSION: This study shows that treatment with levetiracetam reduces interictal epileptiform discharges in children with ADHD. There is a complex relationship between epilepsy, ADHD and epileptiform activity, why it is a need for prospective studies in larger sample sizes, also to ascertain clinical benefits.

Attention-deficit hyperactivity disorder and nocturnal epileptiform activity in children with epilepsy admitted to a national epilepsy center.

The aim of this study was to determine if there exists a relationship between attention-deficit hyperactivity disorder (ADHD) and the quantity of focal nocturnal epileptiform activity on the EEG (FNEA) measured as the percentage of epileptiform activity during non-REM sleep (spike index). This was accomplished with a prospective study of children aged 6-14 years consecutively admitted to our center. Of 362 patients, 44 (12.2%) had previously been diagnosed with ADHD. Twenty-four-hour ambulatory EEG recording and assessment of ADHD according to DSM-IV were performed in 46 children suspected of having ADHD. ADHD was diagnosed in 30. We could not find any correlation between the spike index in 8 children with FNEA and the severity of their ADHD symptoms. This study is underpowered and should be considered a pilot study. There is a need for further investigation of a possible causal effect of FNEA on ADHD symptoms in larger cohorts of patients with FNEA.

Run-off replication of host-adaptability genes is associated with gene transfer agents in the genome of mouse-infecting Bartonella grahamii.

The genus Bartonella comprises facultative intracellular bacteria adapted to mammals, including previously recognized and emerging human pathogens. We report the 2,341,328 bp genome sequence of Bartonella grahamii, one of the most prevalent Bartonella species in wild rodents. Comparative genomics revealed that rodent-associated Bartonella species have higher copy numbers of genes for putative host-adaptability factors than the related human-specific pathogens. Many of these gene clusters are located in a highly dynamic region of 461 kb. Using hybridization to a microarray designed for the B. grahamii genome, we observed a massive, putatively phage-derived run-off replication of this region. We also identified a novel gene transfer agent, which packages the bacterial genome, with an over-representation of the amplified DNA, in 14 kb pieces. This is the first observation associating the products of run-off replication with a gene transfer agent. Because of the high concentration of gene clusters for host-adaptation proteins in the amplified region, and since the genes encoding the gene transfer agent and the phage origin are well conserved in Bartonella, we hypothesize that these systems are driven by selection. We propose that the coupling of run-off replication with gene transfer agents promotes diversification and rapid spread of host-adaptability factors, facilitating host shifts in Bartonella.

1.4Mb recurrent 22q11.2 distal deletion syndrome, two new cases expand the phenotype.

We report two new patients with the 1.4Mb recurrent 22q11.2 distal deletion syndrome. Features common to both children, as well as to several of the previously reported cases, include normal palate, smooth philtrum, hypoplastic alae nasi and delayed development. Both children are small but not growth retarded, and are microcephalic. Their developmental delay is global and most pronounced for language acquisition. One child has unilateral sensorineural hearing loss and encopresis, and the other child has treatment-responsive nocturnal epileptogenic activity. These two new cases confirm the recurrent nature of the deletion and help to further delineate the phenotype.

Mental health problems in children and adolescents referred to a national epilepsy center.

This study aimed to investigate the occurrence of psychiatric morbidity in children and adolescents referred to a tertiary national epilepsy center (inpatient unit) and the extent of the unmet need for psychiatric services in this group. Participants were 74 children and adolescents aged 9-15 referred from February 2001 to October 2002 (67% response rate). The multi-informant (parent, teacher, self-report) Strengths and Difficulties Questionnaires (SDQs) were answered before or at admission. Patients with severe mental retardation or pervasive developmental disorder were excluded. We found a large proportion (77%) with a possible or probable psychiatric disorder. The parents, teachers, and adolescents themselves had higher mean SDQ scores than a British community sample on total difficulties, emotional symptoms, conduct problems, hyperactivity-inattention, peer problems, and impairment, but not self-reported conduct problems. Nearly 80% of the children who probably had a psychiatric disorder had no contact with the psychiatric service.

[A ten-year old boy with progressive neurologic outcome]. / En ti år gammel gutt med progredierende nevrologiske utfall.

BACKGROUND: Rasmussen's encephalitis is a rare chronic inflammatory disease with unknown etiology. Patients with this condition have symptoms of intractable partial epilepsy, often with epilepsia partialis continua combined with a progressive hemiparesis. MATERIAL AND METHODS: The history of a Norwegian ten-year old boy with Rasmussen's encephalitis is described. RESULTS AND INTERPRETATION: The patient had clinical symptoms of Rasmussen's encephalitis. He had intractable partial epilepsy including epilepsia partialis continua. Cerebral MRI showed unilateral right-sided cerebral atrophy and foci of increased signal intensity in cortical grey and subcortical white matter. The boy was operated with right-sided hemispherectomy and is postoperatively seizure free. To our knowledge, this is the first published Norwegian child with Rasmussen's encephalitis. The disorder may be underdiagnosed in Norway. It is important to recognise this disease as early as possible.

[Vagal nerve stimulation in children with drug-resistant epilepsy]. / Vagusnervestimulering hos barn med farmakoresistent epilepsi.

BACKGROUND: To evaluate the clinical efficacy and side effects of vagal nerve stimulation (VNS) in Norwegian children with difficult-to-treat epilepsy. MATERIAL AND METHODS: We have performed an open retrospective study of 60 children with pharmaco-resistant epilepsy who had a VNS implantation between October 1996 and May 2003. The effects and side effects of VNS were evaluated on the basis of the medical records and a questionnaire filled in by the patients and/or their relatives. RESULTS: Forty-six patients (77%), 25 females and 21 males, aged 4-16 years at the time of implantation, filled in the questionnaire. All patients had tried > or = 6 antiepileptic drugs prior to the implantation. Five of them had undergone resective epilepsy surgery. After a mean of 2.5 years of follow up, 33 patients (72 %) reported positive effects of VNS. Twenty-nine patients (63%) reported decreased seizure frequency and/or less severe seizures, 20 (43%) achieved > or = 50 % seizure reduction, but only two became seizure free. Sixteen (35%) experienced a shorter and milder postictal phase. In 10 patients (22%) the need of diazepam treatment to terminate seizures was considerably reduced. Twenty-eight of the children (61%) experienced a positive effect of magnet activation. Twenty-three patients (50%) reported minor and waning side effects. Because most of the patients (32) had their antiepileptic medication changed after the implantation, the results should be interpreted with caution. CONCLUSIONS: A majority of the patients (72%) reported positive effects on seizure frequency and/or epilepsy-related symptoms. The side effects were modest. Our findings support previous reports about VNS being an effective additional treatment in children with refractory epilepsy.

[Epilepsia partialis continua (Kojevnikov's syndrome)]. / Epilepsia partialis continua (Kojevnikovs syndrom).

BACKGROUND: Lesions close to the central sulcus may give rise to focal motor seizures of long duration. This condition is called epilepsia partialis continua (Kojevnikov's syndrome). MATERIAL AND METHODS: Over the last two years, the National Centre for Epilepsy in Norway has treated 12 patients with epilepsia partialis continua. We discuss the occurrence, etiologies, semiology, findings from supplementary investigations, and therapeutic options on the basis of relevant literature and our own experience with these patients. RESULTS AND INTERPRETATION: Morphological lesions were found in 10 out of these 12 patients; cortical dysplasia in 3 patients, brain tumour in 2 patients, cerebral infarction in 2 patients, Rasmussen syndrome in 2 patients, and cerebral haemorrhage from an arteriovenous malformation in 1 patient. 9 patients had intermittent periods of jerking lasting from some hours to several days; the remaining 3 had permanent jerks. One of them had had this condition for 44 years. In 11 patients the jerks were localised to the face and/or the hand. The effect of antiepileptic drugs was disappointing; none became seizure-free. Five patients had undergone surgery. Surgical lesionectomy in this brain area is associated with a high risk of damage to eloquent cortex, but multiple subpial transections may have a seizure-blocking effect. One patient with Rasmussen's syndrome became seizure-free after a functional hemispherotomy.

The louse-borne human pathogen Bartonella quintana is a genomic derivative of the zoonotic agent Bartonella henselae.

We present the complete genomes of two human pathogens, Bartonella quintana (1,581,384 bp) and Bartonella henselae (1,931,047 bp). The two pathogens maintain several similarities in being transmitted by insect vectors, using mammalian reservoirs, infecting similar cell types (endothelial cells and erythrocytes) and causing vasculoproliferative changes in immunocompromised hosts. A primary difference between the two pathogens is their reservoir ecology. Whereas B. quintana is a specialist, using only the human as a reservoir, B. henselae is more promiscuous and is frequently isolated from both cats and humans. Genome comparison elucidated a high degree of overall similarity with major differences being B. henselae specific genomic islands coding for filamentous hemagglutinin, and evidence of extensive genome reduction in B. quintana, reminiscent of that found in Rickettsia prowazekii. Both genomes are reduced versions of chromosome I from the highly related pathogen Brucella melitensis. Flanked by two rRNA operons is a segment with similarity to genes located on chromosome II of B. melitensis, suggesting that it was acquired by integration of megareplicon DNA in a common ancestor of the two Bartonella species. Comparisons of the vector-host ecology of these organisms suggest that the utilization of host-restricted vectors is associated with accelerated rates of genome degradation and may explain why human pathogens transmitted by specialist vectors are outnumbered by zoonotic agents, which use vectors of broad host ranges.

A paradoxical effect of levetiracetam may be seen in both children and adults with refractory epilepsy.

The aim of this prospective, uncontrolled clinical study was to evaluate the tolerability and the efficacy of levetiracetam as add-on treatment in 78 adults and 44 children with intractable epilepsy. The patients' seizure frequency in the 8 weeks baseline period was compared to their seizure frequency after a mean follow-up of 8 months of treatment.A greater than 50% reduction in seizure frequency was achieved in 31 adults (40%) and 9 children (20%), of whom 7 adults (9%) and 3 children (7%) became seizure free. Most often levetiracetam was well tolerated, somnolence being the most frequently reported side effect (18% in adults and 7% in children). However, in 14 adults (18%) and 19 children (43%) levetiracetam was associated with an increase (>25%) in seizure frequency. Such a paradoxical effect, including the development of status epilepticus in three adults and four children, appeared most often in mentally retarded patients during the first 2 months of treatment, and on relatively high doses. Two children developed status epilepticus after 5 and 7 months, respectively. In conclusion, levetiracetam is usually well tolerated as add-on treatment in patients with difficult-to-treat partial onset seizures. By using a lower initial dose and a slower dose escalation than recommended by the manufacturer, a paradoxical effect may perhaps be avoided. In children, doses >20 mgkg(-1) per day should be introduced with caution.

50 million years of genomic stasis in endosymbiotic bacteria.

Comparison of two fully sequenced genomes of Buchnera aphidicola, the obligate endosymbionts of aphids, reveals the most extreme genome stability to date: no chromosome rearrangements or gene acquisitions have occurred in the past 50 to 70 million years, despite substantial sequence evolution and the inactivation and loss of individual genes. In contrast, the genomes of their closest free-living relatives, Escherichia coli and Salmonella spp., are more than 2000-fold more labile in content and gene order. The genomic stasis of B. aphidicola, likely attributable to the loss of phages, repeated sequences, and recA, indicates that B. aphidicola is no longer a source of ecological innovation for its hosts.