LACC1 polymorphisms in inflammatory bowel disease and juvenile idiopathic arthritis

The function of the Laccase domain-containing 1 (LACC1) gene is unknown, but genetic variation at this locus has been reported to consistently affect the risk of Crohn's disease (CD) and leprosy. Recently, a LACC1 missense mutation was found in patients suffering from monogenic forms of CD, but also systemic juvenile idiopathic arthritis. We tested the hypothesis that LACC1 single nucleotide polymorphisms (SNPs), in addition to CD, are associated with juvenile idiopathic arthritis (JIA, non-systemic), and another major form of inflammatory bowel disease, ulcerative colitis (UC). We selected 11 LACC1 tagging SNPs, and tested their effect on disease risk in 3855 Swedish individuals from three case-control cohorts of CD, UC and JIA. We detected false discovery rate corrected significant associations with individual markers in all three cohorts, thereby expanding previous results for CD also to UC and JIA. LACC1's link to several inflammatory diseases suggests a key role in the human immune system and justifies further characterization of its function(s).

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.

Emerging infectious diseases represent an increasing human health problem with many examples of disease outbreaks caused by transmissions from animals to humans, such as, most recently, the bird flu virus. Genes involved in virulence and antibiotic resistance are often carried by mobile elements like plasmids and viruses, which mediate transfer between cells at an amazing speed. Rodents represent a major carrier of infectious agents, and it is therefore particularly important to study the gene transfer processes in bacteria that use rodents as their natural host reservoir. We have studied the genome of a bacterium that is naturally adapted to mice and identified many more putative host-interaction genes than were observed in previously recognized human pathogens. Furthermore, most of these genes are located in a segment of about 25% of the genome, which was massively amplified and packaged into viral particles. This is the first demonstration of targeted packaging of a portion of the bacterial chromosome into viral particles, and we propose that this is a novel strategy for increased exchange of genes involved in the infectious process.

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.

[Vagal nerve stimulation in children with drug-resistant epilepsy]

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.

[A ten-year old boy with progressive neurologic outcome]

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.

[Epilepsia partialis continua (Kojevnikov's syndrome)]

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.

Elevation of cytokines in peritoneal fluid and blood in patients with liver cirrhosis

BACKGROUND/AIMS

Liver cirrhosis, described as the endstage of a necroinflammatory process, is often accompanied by ascites formation. The rationale for this study was the hypothesis that patients with liver cirrhosis have a low-grade chronic inflammatory response, which leads to an increased amount of proinflammatory cytokines accumulated in ascites. Twenty-five patients with liver cirrhosis complicated by ascites and twelve healthy volunteers were prospectively included in the study.

METHODOLOGY

Ascites and blood samples from the patients were obtained for analysis of inflammatory cytokines using enzyme-linked immunosorbent assay methodology. Blood samples were taken from the healthy volunteers to obtain reference values.

RESULTS

Plasma and ascites concentrations of interleukin-1alpha, interleukin-6, and tumor necrosis factor-alpha were significantly elevated in the patients compared with plasma levels in the group of healthy controls. Significant elevation of interleukin-10 concentrations was found in ascites but not in plasma in the patients. There was no significant difference in interleukin-10 levels between patient and control plasma.

CONCLUSIONS

The findings suggest that elevated cytokine concentrations in ascites and serum could perpetuate an inflammatory reaction that may be a source of preservation of an ongoing systemic inflammatory reaction. This may contribute to the maintenance, and even progress, of the liver dysfunction, leading to exaggerated ascites development.

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.

Effect of age and body weight on neurohumoral variables in healthy Cavalier King Charles spaniels

OBJECTIVE

To evaluate the effect of age and body weight on several neurohumoral variables that are commonly altered in heart failure in Cavalier King Charles Spaniels.

ANIMALS

17 healthy privately owned Cavalier King Charles Spaniels, 10 males and 7 females, ranging in age from 0.4 to 9.7 years, and ranging in body weight from 6.6 to 12.2 kg.

PROCEDURE

The clinical condition of the dogs was evaluated by physical examination, thoracic radiography, and echocardiography. Plasma nitrate and nitrite (P-NN), N-terminal atrial natriuretic and brain natriuretic peptides (NT-ANP and BNP, respectively), endothelin (ET-1), urine cyclic guanosine monophosphate (U-cGMP), and urine nitrate and nitrite (U-NN) concentrations were analyzed.

RESULTS

Plasma concentrations of NT-ANP and P-NN increased significantly with age, but plasma NT-ANP and P-NN also correlated significantly, irrespective of age. A modest increase of left atrial size did not explain the increase of NT-ANP and P-NN with age. Concentration of ET-1 correlated positively with heart rate; heart rate did not change with age. Weight had a negative impact on NT-ANP, P-NN, and U-cGMP concentrations and left atrial relative size.

CONCLUSIONS AND CLINICAL RELEVANCE

Age-matched controls are essential for evaluation of NT-ANP and P-NN concentrations and left atrial size. Weight may alter reference values of plasma NT-ANP, P-NN, and urine cGMP concentrations. Natriuretic peptides can be used as further evidence that heart failure exists. The increased plasma concentrations of NT-ANP (but not BNP) and P-NN with aging reflect neurohumoral physiologic changes that must be distinguished from pathologic changes in patients with heart failure.

The effect of lamotrigine on epileptiform discharges in young patients with drug-resistant epilepsy

PURPOSE

In a double-blind crossover study with lamotrigine (LTG), we investigated a possible relationship between the clinical responses and changes of the amount of epileptiform activity in EEG.

METHODS

Twelve patients, aged 4-21 years, with generalized drug-resistant epilepsy who had responded to LTG, completed the study. Twenty-four-hour video-EEGs were taken during control, placebo, and drug phases. The amounts of epileptiform discharges were estimated and compared with the clinical effects.

RESULTS

The duration of periods of repeated epileptiform discharges was significantly reduced during the LTG phase compared with the placebo phase (n = 12, p = 0.04). Ten patients showed a reduction of the amount of epileptiform discharges in the LTG phase by a mean of 81% (range, 17-100%). Periods of repeated epileptiform discharges with duration longer than 30 s were significantly reduced in length (p = 0.03) and number (p = 0.04) during the LTG phase compared with the placebo phase. Shorter periods of epileptiform discharges and the numbers of single epileptiform discharges were not affected. In five patients there was a seizure reduction (>/=50%) concomitant with the reduction of epileptiform discharges in the EEG. The behavior improved during LTG treatment in all patients. The patients became more alert, and their concentration and performance improved, according to their parents and the medical personnel.

CONCLUSIONS

LTG in dosages of 1-8 mg/kg body weight was found to depress relatively long episodes of interictal, repetitive, epileptiform activity in young patients with drug-resistant epilepsy, whereas short episodes were not affected. It depressed seizures in about half of the patients studied but gave improvements of behavior in all patients.

Analysis of CSF amino acids in young patients with generalised refractory epilepsy during an add-on study with lamotrigine

The effect of add-on administration of lamotrigine (1-12 mg/kg per day, 2-12 months) on the levels of neurotransmission related amino acids including gamma-aminobutyric acid (GABA), glutamate, aspartate, glycine and antiepileptic drugs (AEDs) in lumbar cerebrospinal fluid (CSF) was studied in 22 children and young adults with generalised therapy resistant epilepsy. Two lumbar punctures were performed, one prior to, and one following a mean of 5 months (2-12 months) of lamotrigine treatment. Lamotrigine decreased seizure incidence and severity in 12 of the 22 patients without influencing CSF GABA, glutamate, aspartate or glycine levels. Lamotrigine did not alter the concentrations of AEDs in CSF or plasma. However, CSF GABA levels were 86% higher in those patients also treated with gamma-vinyl-GABA (vigabatrin, GVG) compared with patients treated with other combinations and this was not altered by co-medication with lamotrigine. The proposed mechanism of action of lamotrigine, namely that it may inhibit glutamate release in the CNS, is not reflected by changes in CSF glutamate levels. The present findings indicate that CSF GABA, glutamate, aspartate and glycine levels may not be useful as in vivo neurochemical markers in young patients responding to the therapeutic dose of lamotrigine used in this study.

The genome sequence of Rickettsia prowazekii and the origin of mitochondria

We describe here the complete genome sequence (1,111,523 base pairs) of the obligate intracellular parasite Rickettsia prowazekii, the causative agent of epidemic typhus. This genome contains 834 protein-coding genes. The functional profiles of these genes show similarities to those of mitochondrial genes: no genes required for anaerobic glycolysis are found in either R. prowazekii or mitochondrial genomes, but a complete set of genes encoding components of the tricarboxylic acid cycle and the respiratory-chain complex is found in R. prowazekii. In effect, ATP production in Rickettsia is the same as that in mitochondria. Many genes involved in the biosynthesis and regulation of biosynthesis of amino acids and nucleosides in free-living bacteria are absent from R. prowazekii and mitochondria. Such genes seem to have been replaced by homologues in the nuclear (host) genome. The R. prowazekii genome contains the highest proportion of non-coding DNA (24%) detected so far in a microbial genome. Such non-coding sequences may be degraded remnants of 'neutralized' genes that await elimination from the genome. Phylogenetic analyses indicate that R. prowazekii is more closely related to mitochondria than is any other microbe studied so far.

The Rickettsia prowazekii genome: a random sequence analysis

We describe here the first general survey of the genomic content and the coding capacity of the 1.1 Mb genome of Rickettsia prowazekii based on an analysis of a total of 200 kb of unique sequence data collected in a random manner. Based on nucleotide distribution profiles, we estimate that the R. prowazekii genome may have a coding density of 60%-70% and that it may contain a total of circa 800 genes. Here, we have tentatively identified and classified 173 of these genes. Our analysis suggests that the R. prowazekii genome is a highly derived, reduced genome that has lost many genes involved in amino acid biosynthetic pathways and regulatory functions. Furthermore, the R. prowazekii genome seems to lack glycolytic genes, but it does contain genes encoding components of the tricarboxylic acid cycle as well as of the electron transport system. We have also encountered a family of homologous genes coding for ATP/ADP translocases, as observed in several mitochondrial genomes. We relate these findings to previous phylogenetic studies that suggest that Rickettsia and mitochondria share a common ancestor.

The efficacy of lamotrigine in children and adolescents with refractory generalized epilepsy: a randomized, double-blind, crossover study

PURPOSE

We report a double-blind, placebo-controlled crossover study of lamotrigine (LTG) as add-on treatment in therapy-resistant, generalized epilepsy in children and adolescents (n = 30).

METHODS

Twenty patients had Lennox-Gastaut syndrome. Each patient acted as his or her own control. LTG and placebo were randomly added to existing antiepileptic medication (AEDs). The LTG dosage was individualized in an open phase preceding the placebo/treatment phase. Patients who responded to LTG in the open phase went on to the double-blind phase. "Responders " were defined as patients with a >50% seizure reduction or less severe seizures or both, or improved behavior or improved motor skills or both. "Nonresponders" were defined as children who showed no positive effects of LTG with plasma levels of < or = 10 microg/ml or children who had adverse events during the open phase.

RESULTS

There was a clear statistically significant reduction of seizure frequency in LTG compared with placebo treatment. None of the children studied showed abnormal biochemical or hematologic findings, or changes in plasma levels of concomitantly administered AEDs.

CONCLUSIONS

LTG is a well-tolerated and effective treatment in children with intractable generalized epilepsies, including those with Lennox-Gastaut syndrome. The study design allowed a double-blind placebo-controlled assessment of LTG although the participating children used 19 different AED combinations at entry.

No increase in carbamazepine-10,11-epoxide during addition of lamotrigine treatment in children

It has been suggested that lamotrigine (LTG) may enhance the toxicity of carbamazepine (CBZ) by increasing the concentration of the active metabolite carbamazepine-10,11-epoxide (CBZ-E) in adult patients. The authors investigated this hypothesis in an add-on study in 11 children and 3 adolescents, aged 6-22 years, who had been treated for more than 1 year with CBZ in monotherapy or with CBZ in combination with one or two other antiepileptic drugs. The LTG dosage was increased step by step until clinical response or side effects were observed. The plasma concentrations of LTG, CBZ, and CBZ-E were monitored during steady state conditions before and after the addition of LTG. It was found that LTG had no effect on mean CBZ concentrations and that it decreased rather than increased the mean plasma concentration of CBZ-E from 6.4 +/- 2.6 to 4.9 +/- 2.4 mumol/l (mean +/- SD, n = 14, P = 0.019). Observed side effects were diplopia in two children, agitation in two, and increased number of seizures in one. None of these five patients had unusually high CBZ-E levels when the side effect developed. It is concluded that addition of lamotrigine in children treated with carbamazepine children does not result in a pharmacokinetic interaction with a toxic accumulation of carbamazepine-10,11-epoxide.

Leukocyte hydrogen peroxide production in a surgical wound in mice. The effects of an amide local anaesthetic

The oxygen metabolism of polymorphonuclear leukocytes (PMN) is of importance in local tissue repair processes. Amide local anaesthetics are commonly used to relieve surgical wound pain. The cellular effects of local anaesthetics in vivo is poorly described in the literature. However, interactions between amide local anaesthetics and the oxygen metabolism of leukocytes have been reported. To extend that knowledge, this paper investigates the influence of lidocaine treatment on the production of hydrogen peroxide (H2O2) by leukocyte oxygen metabolism. A soft tissue chamber model in the mouse was used, allowing measurements of the H2O2 production spontaneously and after phorbol myristate acetate (PMA) addition, from two different leukocyte pools. Exudate leukocytes were generally more reactive to PMA stimulation in comparison to tissue chamber adherent leukocytes. Topically administered lidocaine significantly influenced the number of leukocytes in the wound exudate at 24 h postoperatively. Exudate leukocytes, topically exposed to lidocaine, showed an enhanced H2O2 production in comparison to leukocytes receiving lidocaine systemically. At 6 days, the viability and the H2O2 production differed significantly between the group receiving topically applied lidocaine in comparison to placebo. We conclude that the wound healing process may be effected by topically applied lidocaine, administered in clinical doses, at least via interference with leukocyte oxygen metabolism.

Pharmacokinetic interactions between lamotrigine and other antiepileptic drugs in children with intractable epilepsy

PURPOSE

We wished to determine the oral pharmacokinetics of lamotrigine LTG and to assess possible interactions with other AEDs in an unselected population of children. Concentration data in plasma and in CSF for lamotrigine as well as for the other AEDs are presented.

METHODS

Thirty-one children, children and young adults aged > 2 years with intractable generalized epilepsy despite adequate duration and dose of at least three conventional AEDs were studied.

RESULTS

There was a linear relation between the dose administered and the maximal plasma concentration, indicating that saturation of absorption or elimination mechanisms did not occur in the dose range studied. The median elimination half-life (t1/2) in patients receiving concomitant valproate (VPA) was 43.3 h; in patients receiving carbamazepine (CBZ) and/or phenobarbital (PB), it was 14.1 h; and in patients receiving both VPA and CBZ/ PB or other antiepileptic drugs (AEDs), it was 28.9 h. No clinically important changes in the plasma levels of CBZ, VPA, valproate, ethosuximide, or PB were observed in the follow-up period (2-12 months). No dose adjustments of concomitant AEDs were necessary. The plasma concentration of clonazepam (CZP) was reduced when LTG was introduced.

CONCLUSIONS

The complex interaction between LTG and other AEDs in children with intractable epilepsy makes therapeutic drug monitoring (TDM) desirable.

Monocyte activation on titanium-sputtered polystyrene surfaces in vitro: the effect of culture conditions on interleukin-1 release

The release of interleukin-1 alpha (IL-1 alpha) by human peripheral blood monocytes cultured for 24 and 48 h on polystyrene (PS) and titanium-sputtered polystyrene (Ti) was evaluated. Magnetron sputtering of the PS surfaces resulted in a formation of a 50-nm-thick coat, consisting of an outer layer of TiO2. Monocytes released IL-1 alpha without the addition of exogenous stimuli. A doubling of the culture time from 24 to 48 h did not have a major effect on the amount of IL-1 alpha released. The IL-1 alpha levels were increased by addition of lipopolysaccharide (LPS). High concentrations of PS particles (1 and 3 microns diameter) were equally effective stimuli for IL-1 alpha release as LPS. Preadsorption of fibronectin to culture plates augmented LPS-stimulated IL-1 alpha secretion, whereas preadsorbed fibrinogen had an inhibitory effect. Our observation indicate a direct activation of monocytes by PS and Ti, resulting in IL-1 alpha secretion, which is modified by protein adsorption and exogenous stimuli.

Ex vivo analysis of leukocyte hydrogen peroxide production using a bi-plate model in mice

Implantation of artificial materials is followed by inflammation and wound healing, where phagocytic cells play an important role. The mechanisms whereby the implant surface may elicit and modulate leukocyte functions in vivo are not understood, partly due to the technical difficulties of examining the local inflammatory events in vicinity of the material-tissue interface with conventional biochemical and immunological techniques. In the present study a newly developed biplate implant was inserted subcutaneously in the mouse. Leukocytes from the local inflammatory exudate and leukocytes associated to the surface of the implants were retrieved after 1 and 6 days and separately assayed with respect to hydrogen peroxide (H2O2) production ex vivo. Implantation caused a local accumulation of predominantly mononuclear cells in the surrounding subcutaneous tissue. The H2O2 production was found to be low in both the subcutaneous exudate and the implant-associated leukocytes, irrespective of implant material and implantation times. However, ex vivo-stimulation with phorbol myristate acetate (PMA) caused an enhanced H2O2 production. These observations show that biplate implants do not maximally activate the oxidative metabolism of the recruited leukocytes. The exudate leukocytes were more responsive to PMA stimulation in comparison with implant-associated leukocytes, indicating that properties of the implant surface and possibly surface-associated proteins could modify the responsiveness of the phagocytic cells at the implant site. Our results suggest that the present biplate model may be suitable for further studies on local production of oxygen metabolites and function of leukocytes at implanted biomaterials.

Leukocyte recruitment and turnover in an experimental inflammatory exudate

The turn-over of leukocytes at sites of inflammation in vivo is to a large extent uninvestigated, mainly due to the technical difficulties associated with sampling and analysis of the inflammatory exudate. This paper investigates the immigration of fluorescently labeled granulocytes into exudate chambers at 8 h and at 1, 3, and 6 days after implantation into abdominal muscle of rat. In each experiment, the circulating granulocytes were labeled by intravenous administration of the DNA-labeling fluorochrome Hoechst 33342 and allowed to migrate into the chamber during 6 h before harvesting the chamber exudate. The rate of granulocyte immigration into the chamber varied considerably over time, showing a minimum at 3 days after implantation. The resulting kinetic pattern of granulocyte numbers in the exudate showed a two-step appearance, different from that of earlier determinations in soft tissue. A comparison between the calculated rates of granulocyte immigration and the total number of granulocytes present in the exudate at different times indicated that all immigrated cells survived in the chamber for the entire observation period of 6 days.

Flunarizine of limited value in children with intractable epilepsy

Fourteen ambulatory children and adolescents with intractable epilepsy were studied in an open phase II study to investigate the pharmacokinetics and pharmacodynamics of flunarizine as an add-on treatment. Flunarizine was given in increasing doses starting with 0.1-0.3 mg/kg/day until effect was observed or a steady-state plasma concentration of 50-60 ng/ml was reached. Treatment was continued for 3 months at steady state. Pharmacokinetics were determined during the immediate posttreatment period. Positive antiepileptic effect (> or = 50% reduction in seizure frequency) was observed in 4 of 14 patients (29%; 95% CI: 52-5). Independently of antiepileptic effect, 10 of 14 parents (71.4%; 95% CI: 95-48) observed positive cognitive effects. In all patients treatment was withdrawn due to either lack of effect or weight gain. Flunarizine was rapidly absorbed; mean time of peak concentration (Tmax) was 2.7 hours (range: 1-8). The mean terminal half-life was 23.2 days (range: 7-48), the total plasma clearance of flunarizine per fraction of the dose absorbed (CLp/F) was 0.28 ml/min/kg (range: 0.07-042), and the volume of distribution of flunarizine per fraction of the dose absorbed (Vd/F) was 187 L/kg (range: 99-348). We conclude that flunarizine (0.1-0.3 mg/kg/day) seems to be of limited antiepileptic value in children with intractable epilepsy. The pharmacokinetic profile of flunarizine complicates its clinical use.

Leucocyte accumulation and leukotriene B4 release in response to polyglactin 910 and expanded polytetrafluoroethylene in hollow chambers in the rat

The acute inflammatory reaction elicited after implantation of polymer membranes used clinically to promote bone healing and augmentation was studied in a soft tissue titanium chamber model. The two materials compared were non-degradable expanded polytetrafluoroethylene (ePTFE) and degradable polyglactin 910, a copolymer of 90% polyglycolic acid and 10% polylactic acid. The membranes were implanted in the titanium chamber for 24 h and 6 d. The number of leucocytes increased for both materials, whereas the leukotriene B4 (LTB4) content decreased over time. In both groups polymorphonuclear granulocytes predominated. The number of leucocytes was significantly higher in chambers with polyglactin 910 than ePTFE. In contrast, the LTB4 content was higher in chambers with ePTFE than polyglactin 910. No differences in cell viability were observed between the materials tested. This study shows that both degradable and non-degradable polymers elicit a marked influx and activation of inflammatory cells during early healing in soft tissues.

Inhibitory effects of amide local anaesthetics on stimulus-induced human leukocyte metabolic activation, LTB4 release and IL-1 secretion in vitro

The anti-inflammatory effects of the amide local anaesthetics lidocaine and bupivacaine were evaluated in vitro by examination of the metabolic activation and secretory responses of human polymorphonuclear granulocytes (PMNGs) and mononuclear cells. Pretreatment with lidocaine or bupivacaine had a dose-dependent inhibitory effect on PMNG luminol-amplified chemiluminescence stimulated by bovine serum albumin (BSA)/anti-BSA immune complexes (IC) or by serum-opsonized zymosan (SOZ) particles. Both lidocaine and bupivacaine inhibited the release of the inflammatory mediators leukotriene B4 (LTB4) and interleukin-1 (IL-1) evaluated by radioimmunoassay (RIA). Pretreatment of suspended PMNGs and monocytes with the anaesthetics caused a marked inhibition of LTB4 release when the cells were stimulated with SOZ. In short-term (24 h) cultures of mononuclear cells the addition of lidocaine or bupivacaine reduced, in a dose-dependent manner, the level of IL-1 detected after stimulation with lipopolysaccharide (LPS). In all three assays (chemiluminescence, LTB4 and IL-1 RIA) bupivacaine was found to be more potent than lidocaine. The present results show that amide local anaesthetics have marked suppressive effects on the metabolic activation and secretory functions of leukocytes stimulated by different agonists. Although the detailed mechanisms for these effects are not known, they may explain part of the potent anti-inflammatory actions of local anaesthetics previously described in vivo.

Influence of lidocaine on leukocyte function in the surgical wound

The inflammatory response of the wound is mediated to a large extent by leukocytes, which play an important role in the wound healing process. Local anesthetics, which are routinely administered before minor skin surgery and for postoperative pain relief, have been shown to have diverse effects on wound healing. Local anesthetics have also been reported to induce potent inhibition of leukocytes in vitro, although their effects on leukocyte activity in the surgical wound have not been elucidated. The present study investigated the in vivo effects of lidocaine on leukocyte function in the surgical wound of rats by sampling leukocytes from hollow titanium implants. The surgical wound was treated with lidocaine or placebo after implantation of the titanium chamber and before skin closure. Leukocyte metabolic activity was measured by chemiluminescence. Cell count was analyzed in a Bürker chamber. Results showed progressive increase in leukocyte counts in the wounds of control animals and significantly lower cell counts in the wounds of lidocaine-treated animals 48 h (P less than 0.05) and 72 h (P less than 0.05) after surgery. A pronounced inhibition of the metabolic response to serum-opsonized zymosan was seen after 8 h in the lidocaine-treated animals versus controls (P less than 0.05). After 24 h, leukocyte metabolic activity decreased dramatically in the control group and remained at a low level until 72 h after surgery. In the lidocaine-treated group, the leukocyte response to zymosan remained constantly low throughout the study. The effects of lidocaine were not a result of impaired leukocyte viability.(ABSTRACT TRUNCATED AT 250 WORDS)

Leukotriene B4, interleukin 1 and leucocyte accumulation in titanium and PTFE chambers after implantation in the rat abdominal wall

The inflammatory reaction elicited after implantation of non-biologic materials was studied by analysis of the exudate in pure titanium or polytetrafluorethylene chambers 1-9 d after insertion in the abdominal wall of the rat. In chambers made of pure titanium, the number of leucocytes increased about twofold from 1.8 x 10(6)/ml to 4.1 x 10(6)/ml between 24 h and 6 d, whereas a larger increase from 2.1 x 10(6)/ml to 8.3 x 10(6)/ml was observed in the polytetrafluorethylene chambers. Irrespective of implant material, polymorphonuclear granulocytes constituted the vast majority of leucocytes (greater than 81%). After 24 h the leukotriene B4 content was slightly higher in polytetrafluorethylene chambers than in titanium chambers. In contrast to the titanium chambers, a marked increase in leukotriene B4 levels was detected in polytetrafluorethylene chambers 6 d after insertion, whereas the greatest amount of leukotriene B4 in titanium chambers was measured at 9 d. Interleukin 1 was only detected in both types of chambers after 6 d. The present study, together with previous findings, shows that the materials used in this study elicit different degrees of inflammatory reactions in the chamber exudate. Since the number of leucocytes in the exudate retrieved from the chambers correlated well with the leukotriene B4 levels, it is suggested that leukotriene B4, but not interleukin 1, may be an important mediator for polymorphonuclear granulocyte migration into the implant-tissue interface.(ABSTRACT TRUNCATED AT 250 WORDS)

Hollow implants in soft tissues allowing quantitative studies of cells and fluid at the implant interface

In order to study the early cellular response in the fluid phase found close to implants in soft tissues, an experimental method using a hollow implant was developed. The fluid present in an interior chamber communicating with the exterior of the implant was analysed. Polymorphonuclear granulocytes (PMNGs) were predominant during the study (1-9 days). In titanium implants a slight increase in cell numbers with time was noted, whereas in polytetrafluoroethylene (PTFE) implants, a sharp increase in cell numbers was observed. Preliminary studies showed that sufficient amounts of fluid and cells could be retrieved for analysis of protein composition and inflammatory cell activation.