Single layer graphene induces load-bearing molecular layering at the hexadecane-steel interface

The influence of a single layer graphene on the interface between a polished steel surface and the model lubricant hexadecane is explored by high-resolution force microscopy. Nanometer-scale friction is reduced by a factor of three on graphene compared to the steel substrate, with an ordered layer of hexadecane adsorbed on the graphene. Graphene furthermore induces a molecular ordering in the confined lubricant with an average range of 4-5 layers and with a strongly increased load-bearing capacity compared to the lubricant on the bare steel substrate.

Randomized clinical trial of prophylactic transanal irrigation versus supportive therapy to prevent symptoms of low anterior resection syndrome after rectal resection

Background

Low anterior resection syndrome (LARS) is a frequent problem after rectal resection. Transanal irrigation (TAI) has been suggested as an effective treatment in patients who have developed LARS. This prospective RCT was undertaken to evaluate the effect of TAI as a prophylactic treatment to prevent symptoms of LARS.

Methods

Patients who had undergone ultralow rectal resection were randomized to start TAI on a daily basis, or to serve as a control with supportive therapy only after ileostomy closure. All patients were seen after 1 week, 1 month and 3 months, and the maximum number of defaecation episodes per day and night documented during follow‐up. Wexner score, LARS score and Short Form 36 questionnaire responses were evaluated in both groups.

Results

Thirty‐seven patients could be evaluated according to protocol (TAI 18, control 19). The maximum number of stool episodes per day and per night was significantly lower among patients who underwent TAI at 1 month (median 3 versus 7 episodes/day in TAI versus control group, P = 0·003; 0 versus 3 episodes/night, P = 0·001) and 3 months (3 versus 5 episodes per day, P = 0·006; 0 versus 1 episodes/night, P = 0·002). LARS scores were significantly better in the TAI group after 1 month (median 16 versus 32 in control group; P = 0·044) and 3 months (9 versus 31; P = 0·001). A significantly better result in terms of Wexner score was seen in the TAI group after 3 months (median 2 versus 6 in controls; P = 0·046).

Conclusion

Prophylactic TAI led to a significantly better functional outcome compared with supportive therapy for up to 3 months. Registration number: DRKS00011752 ( http://apps.who.int/trialsearch/).

Cognitive-behavioral screening in elderly patients with new-onset epilepsy before treatment

OBJECTIVES

Cognitive comorbidity at epilepsy onset reflects disease severity and provides a baseline estimate of reserve capacities with regard to the effects of epilepsy and its treatment. Given the high incidence of epilepsy at an older age, this study analyzed objective and subjective cognition as well as quality of life in elderly patients with new-onset focal epilepsy before initiation of anti-epileptic treatment.

MATERIALS AND METHODS

A total of 257 untreated patients (60-95 years of age) with new-onset epilepsy underwent objective assessment of executive function (EpiTrack) and performed subjective ratings of cognition (Portland Neurotoxicity Scale) and quality of life (QoL; QOLIE-31).

RESULTS

According to age-corrected norms, 58% of patients (N=257) demonstrated deficits in executive function; major determinants were cerebrovascular etiology, neurological comorbidity, and higher body mass index. Subjective ratings indicated deficits in up to 27% of patients. Self-perceived deficits were associated with neurological, cardiovascular, and/or psychiatric comorbidity, whereas poorer QoL was related to neurological comorbidity and female gender. Objectively assessed executive functions correlated with subjective social functioning, energy, motor function, and vigilance.

CONCLUSIONS

We found a relatively high QoL, a low rate of subjective impairment, but a high incidence of objective executive deficits in untreated elderly patients with new-onset epilepsy. Neurological status and body mass index, rather than seizure frequency or severity, were risk factors for cognitive impairment. Given the relevance of cognition in the course of epilepsy and its treatment, routine screening before treatment initiation is highly recommended.

[Drug treatment of epilepsy]

Modern medical treatment of epilepsy renders two out of three newly diagnosed epilepsy patients seizure-free. More than 20 drugs are currently available and even for epilepsy specialists it may not be easy to select the drug which is best suited for the individual patient. Current guidelines recommend drugs with proven efficacy and optimal tolerability that address the individual needs of the patient. Non-enzyme-inducing agents are preferred if possible, to protect the patient from loss of efficacy when taking other medications for life-threatening disorders. In one out of three patients, seizure freedom is currently not possible due to drug-resistance, which requires a prompt diagnostic and therapeutic reevaluation of the epilepsy.

[Primary brain tumors and brain metastases. Symptomatic epilepsy and driving ability - systematic review and expert opinion]

PURPOSE

Primary brain tumors and metastases are common causes of symptomatic epilepsy. Seizures, neurological and neuropsychological deficits can interfere with driving ability. The present paper aims to systematically review the incidence of epileptic seizures in brain tumor patients and to discuss driving ability in the context of the current German guidelines and expert opinions.

METHODS

To evaluate the incidence of epileptic seizures which occur at the beginning and in the course of the disease, we performed a systematic literature research in PubMed from 1960 to 2007. Additionally on the basis of this data we performed a survey collecting expert opinions regarding the driving ability of brain tumor patients from members of the German working groups "Arbeitsgemeinschaft für prächirurgische Epilepsiediagnostik und operative Epilepsietherapie" (Working Group for Presurgical Epilepsy Diagnostics and Operative Epileptic Therapy) and "Neuroonkologische Arbeitsgemeinschaft" (Neuro-oncological Working Group).

RESULTS

The incidence of epileptic seizures depends on the entity, dignity and localization of the tumor. The driving ability of brain tumor patients is not explicitly regulated in Germany. Of the interviewed experts 72% judged the guidelines to be precise enough and 44% did not want to deprive the patients of their driving ability without a first seizure, independent of the individual risk.

DISCUSSION

The available studies are methodologically insufficient and show that a further evaluation is necessary to assess the driving ability. Possible restrictions of the driving ability in patients with a high risk of seizures in the course of the disease have to take into account the balance between individual rights and the interests of the general public.

Association between structural abnormalities and fMRI response in the amygdala in patients with temporal lobe epilepsy

OBJECTIVE

The goal of this study was to investigate whether dysplastic amygdalae show an impaired response as revealed by functional MRI (fMRI).

METHODS

A fearful face fMRI paradigm using video sequences, as we have recently applied, was used in 25 patients with temporal lobe epilepsy (TLE): 24 had mesial TLE (14 right-, nine left-sided, one bilateral); one left lateral neocortical TLE. T1-, T2-weighted and fluid attenuated inversion recovery (FLAIR) MRI sequences were assessed for the detection and categorisation of structural amygdalar abnormalities according to size and MR signal intensity. Of the 25 patients, five patients had probable dysplastic amygdala (pDA): two right- and three left-sided.

RESULTS

A fearful face paradigm led to significant amygdalar activation in all but one patient (p<0.05). In 15 (60%) of the patients amygdalar activation was found contralateral and in four (16%) ipsilateral to the side of seizure onset. Bilateral amygdalar activation was registered in five (20%) patients. In two patients with right-sided and one with left-sided pDA, fMRI activation was observed only in the contralateral amygdala. In two out of three patients with left-sided pDA we found significant ipsilateral amygdalar fMRI-responses.

CONCLUSION

Unilateral pDA does not necessarily affect the amygdalar fMRI BOLD-response.

Oxcarbazepine treatment in male epilepsy patients improves pre-existing sexual dysfunction

OBJECTIVE

To collect data on sexual dysfunction in a larger population of male patients with epilepsy treated with oxcarbazepine in a naturalistic setting.

PATIENTS AND METHODS

Six hundred seventy-three adult male patients with partial epilepsy in whom monotherapy with oxcarbazepine was indicated were evaluated at baseline and after approximately 12 weeks of treatment with regard to the number of seizures and occurrence of any adverse drug reactions. All patients were questioned regarding their sexual function.

RESULTS

Out of 228 patients with pre-existing sexual function impairment at baseline, an improvement was observed in 181 (79.4%) patients, 23 (10.1%) patients experienced no impairment at the final visit. The improvements were more marked in those patients, who were pretreated with enzyme-inducing antiepileptic drugs. No worsening of the sexual dysfunction was observed.

CONCLUSIONS

Oxcarbazepine was found to have beneficial effects on sexual dysfunction and to be effective and well tolerated in male patients with partial epilepsy.

Current approaches to the use of generic antiepileptic drugs

Generic substitution is encouraged as a cost containment strategy for the management of health care resources. However, in epilepsy, the consequences of loss of symptom control are important, and antiepileptic drugs have narrow therapeutic indices. For this reason, generic substitution may be problematic, and certain health authorities have excluded antiepileptic drugs from overall policy recommendations on generic prescribing. The absence of bioequivalence data among generic forms and the relatively broad criteria for bioequivalence with the branded drug allow differences in drug exposure to arise that may be clinically relevant and necessitate monitoring of plasma levels when switching formulations to avoid loss of seizure control or emergence of side effects. Management of these issues carries a significant cost, which should be weighed carefully against the cost savings acquired when purchasing the drug. Both physicians and patients have a right to be informed and approve before pharmacists make a generic substitution or switch between generics.

[Neuropsychological outcome following intrauterine exposure to valproate]

A number of recent studies suggest a link between in utero exposure to valproate (VPA) and low IQ and behavioural disorders in children of mothers with epilepsy. In this review, a commission of the German Section of the International League Against Epilepsy discusses the evidence in the literature and practical recommendations for the use of VPA in women of childbearing potential. It is concluded that despite methodological shortcomings--largely due to the complexity of the problem and small case numbers in prospective studies--the existing data are sufficiently alarming to require great caution in the use of VPA in women who could become pregnant. The underlying mechanisms of how antiepileptic drugs may lead to neurodevelopmental problems are unclear. Further prospective studies are urgently needed to clarify this clinically important issue, and a collaborative study is suggested based on the international network established by the European Registry of Antiepileptic Drugs and Pregnancy.

Levetiracetam: a long-term follow-up study of efficacy and safety

OBJECTIVES

To evaluate the efficacy and safety of long-term add-on treatment with levetiracetam 1,000-4,000 mg/day.

PATIENTS AND METHODS

In this multicenter, open-label follow-up study, 505 patients, from 10 European countries, who had benefited from previous add-on treatment with levetiracetam in a clinical trial or compassionate-use program were enrolled; 274 (54.3%) stayed to the end. Most then continued levetiracetam by prescription or in a named patient program, where it was not yet commercially available. Mean treatment duration was 1,045 days (range: 24 days to >7 years). Median daily dosage was 3,000 mg/day (range: 250-6,000 mg/day), with 250 (49.5%) patients receiving levetiracetam for >3 years.

RESULTS

Median total and partial seizure frequency per week over the evaluation period were 0.8 and 0.7; seizure frequency per week was generally stable over time and remained low. There was a probability of 6.6% of remaining seizure-free for the first 3 years, and of 18.9% of having a seizure-free period of at least 3 years at any time. Most adverse events were mild or moderate and unrelated to study drug. Levetiracetam was well tolerated, and provided stable seizure control during long-term treatment.

Role of valproate across the ages. Treatment of epilepsy in the elderly

In June 2005, a team of experts participated in a workshop with the objective of reaching agreement on several important aspects of valproate in the treatment of elderly patients with epilepsy. Epilepsy in the elderly is relatively common and its incidence increases for each decade after age 60. The aetiology and manifestations of epilepsies in the elderly are complex because of comorbidity and other underlying risk factors. A consensus was reached that elderly patients who present with a seizure disorder should be referred rapidly to a specialist and that diagnosis should be improved by using a multidisciplinary team of cardiologists, neurologists and epilepsy experts (syncope, falls and seizure specialists). This is especially important to avoid mistreatment with antiepileptic drugs (AEDs). There was consensus that the elderly are generally more susceptible to the adverse effects of AEDs than younger adults. For these reasons, in older persons AEDs should be started at low dosages, and titrated slowly according to clinical response. Some of the most troublesome side effects of AEDs in the elderly include sedation and cognitive side effects, as well as osteoporosis. Drug-drug interactions should be given special consideration. There was consensus that the pharmacokinetics of all AEDs are altered in the elderly, and that the most significant change common to all AEDs is a moderate reduction in renal and metabolic clearance. Predicting pharmacokinetic changes in the individual, however, can be very difficult because multiple factors contribute to a high inter-patient variability. There was agreement on the advantages and disadvantages of the use of valproate in the elderly, and consensus that valproate is a useful option in this population. There was no consensus, however, on whether valproate should be considered among the preferred first-line treatments in the elderly.

Amygdala fMRI lateralizes temporal lobe epilepsy

OBJECTIVE

To characterize the clinical value of an fMRI task activating the amygdala in controls and patients with mesial temporal lobe epilepsy (MTLE).

METHODS

A fearful face fMRI paradigm using video sequences was developed and investigated in 17 patients with epilepsy (12 had MTLE [6 right- and 6 left-sided]) and 17 healthy control subjects. Reproducibility was demonstrated by reimaging 12 of the control subjects. In addition, parahippocampal activation was measured using Roland's Hometown Walking Task within the same session in all patients and in nine of the control subjects.

RESULTS

A fearful face paradigm led to significant amygdala activation (p < 0.001) in all subjects. Amygdala activation was bilateral in control subjects and clearly lateralized in patients with MTLE. Dissociated amygdala and parahippocampal activation was found in three MTLE patients. A combination of results from both fMRI paradigms improved the lateralization of the side of seizure onset in patients with MTLE.

CONCLUSIONS

fMRI activation of the amygdala evoked by an animated fearful face paradigm is strong, reproducible, and specific in individual subjects. The combination of the fearful face paradigm and Roland's Hometown Walking Task provides a more reliable presurgical mapping of mesial temporal lobe structures.