P01.08.A Perioperative Levetiracetam for seizure prophylaxis in seizure naive brain tumor patients with focus on neurocognitive functioning

Background

In seizure-naive brain tumor patients, the efficacy of perioperative prophylactic antiepileptic drugtreatment remains controversial. In case of administration, the common preferred drug is levetiracetam (LEV) because of its favorable pharmacological profile. Research to date has not sufficiently determined how LEV affects cognition in the short term as it does in the perioperative period. The objective of this prospective study was to examine the neurocognitive functioning of seizure-naive brain tumor patients after receiving LEV perioperatively.

Material and methods

Patients with supratentorial brain tumor undergoing surgery received LEV three days before until seven days after surgery as seizure prophylaxis. Cognitive functioning (NeuroCogFX), LEV plasma-levels, hematotoxicity, side-effects, as well as health-related quality of life (HRQoL, Qolie31), were recorded preoperatively before (Baseline) and after onset of LEV (Pre-Op), 4-6 days postoperatively (Post-Op) and 21 days postoperatively (Follow-Up).

Results

No significant changes in cognitive functioning and HRQoL were seen after onset of preoperative LEV. There was a significant improvement of NeuroCogFX total-score at Follow-Up (p=0.004) compared to Baseline. The overall-score Qolie31 showed simultaneous improvement patterns as cognitive functioning (p< 0.001). The most frequent side effect related to study drug was somnolence (in 24% of patients).

Conclusion

Following LEV therapy, a significant improvement of cognitive functioning, as well as an improvement in HRQoL, were detected postoperatively. This is presumably due to the debulking effect of the surgery. Nevertheless, LEV has no detrimental effect on cognitivefunctioning in the perioperative phase in seizure-naive brain tumor patients.

The Course of Migraine—A Diary Study in Unselected Patients

The course of disease and the predictive value of depression and anxiety in patients with migraine were prospectively examined. We recruited 393 migraineurs through articles in newspapers and performed a follow-up examination 30 months later. At baseline and follow-up, patients underwent a semi-structured interview, filled out the Headache Impact Test (HIT-6), Self-rating Depression Scale (SDS) and Self-rating Anxiety Scale (SAS) and they kept a headache diary for 30 days. One hundred and fifty-one patients (38.6%) were seen at follow-up. The baseline data of patients with and without follow-up were comparable. At follow-up the number of headache days per month had decreased from 9.6 ± 5.8 to 8.1 ± 6.3 ( P < 0.001) and the proportion of patients with chronic headache (15.4%) and medication overuse (13%) had remained stable. SDS and SAS scores were associated with a high migraine frequency and high initial SDS scores predicted high migraine frequency at follow-up. This longitudinal study in unselected patients with migraine not excluding subjects with chronic headache, medication overuse, depression or anxiety does not point towards migraine as a progressive disease in the vast majority of patients and confirms the importance of psychiatric comorbidity.

Constitutive expression of the defense-related Rir1b gene in transgenic rice plants confers enhanced resistance to the rice blast fungus Magnaporthe grisea

The Rirlb gene of rice (Oryza sativa) is one of a set of putative defense genes whose transcripts accumulate upon inoculation of rice with the non-host pathogen Pseudomonas syringae pv. syringae. It belongs to a family of genes encoding small extracellular proteins so far only identified in cereals. To assess the function of the Rirlb gene in rice blast resistance, it was placed under the control of the CaMV 35S promoter and transferred into rice plants of the japonica variety Taipei 309 by biolistic transformation of immature embryos. Two out of 12 hygromycin-resistant regenerated plants (OE1 and OE3) were fertile. DNA gel blot analysis suggested that these two T0 plants were independent transformants, each of which had stably incorporated one complete copy of the transgene into the genome. In addition, the OE1 plant appeared also a contain a rearranged copy or incomplete copy. T1 plants homozygous for the transgene were identified by DNA gel blot analysis of individual T2 progeny and further propagated. Expression analysis of the transgene showed that the transgene was active both in T1 plants and homozygous decendants. Challenge inoculation of homozygous transgenic plants with Magnaporthe grisea, the causal agent of rice blast disease, revealed that both independent transgenic lines were more resistant than the untransformed wild type, suggesting that over-expression of the Rirlb gene confers partial resistance against this important pathogen.

Syringolin-mediated activation of the Pir7b esterase gene in rice cells is suppressed by phosphatase inhibitors

Inoculation of rice plants (Oryza sativa) with the nonhost pathogen Pseudomonas syringae pv. syringae leads to the activation of defense-related genes and ultimately to induced resistance against the rice blast fungus Pyricularia oryzae. One of the molecular determinants of P. syringae pv. syringae that is recognized by the plant cells and evokes these defense responses is syringolin A, an elicitor that is secreted by the bacteria under appropriate conditions. In order to investigate signal transduction events elicited by syringolin A, the response of cultured rice cells to syringolin A application was analyzed. Cultured rice cells were able to sense syringolin A at concentrations in the nanomolar range as observed by the transient accumulation of Pir7b esterase transcripts. Syringolin A-mediated Pir7b transcript accumulation was inhibited by cycloheximide, indicating that de novo protein synthesis was required. Calyculin and okadaic acid, two protein phosphatase inhibitors, blocked Pir7b gene induction, whereas the serine/threonine protein kinase inhibitors staurosporine and K-252a had no effect on Pir7b transcript levels. Actin transcript levels were essentially not affected by inhibitor treatments over the experimental time span. These results imply that dephosphorylation of a phosphoprotein is an important step in the syringolin A-triggered signal transduction pathway.

Characterization of the rice pathogen-related protein Rir1a and regulation of the corresponding gene

In rice (Oryza sativa L.), local acquired resistance against Pyricularia oryzae (Cav.), the causal agent of rice blast, can be induced by a preinoculation with the non-host pathogen Pseudomonas syringae pv. syringae. We have cloned a cDNA (Rir1a) and a closely related gene (Rir1b) corresponding to transcripts that accumulate in leaf tissue upon inoculation with P. syringae pv. syringae. The cDNA encodes a putative 107 amino acid protein, Rir1a, that exhibits a putative signal peptide cleavage site in its hydrophobic N-terminal part and a C-terminal part that is relatively rich in glycine and proline. The Rir1b gene contains a Tourist and a Wanderer miniature transposable element in its single intron and encodes a nearly identical protein. Rir1a is similar in sequence (ca. 35% identical and ca. 60% conservatively changed amino acids) to the putative Wir1 family of proteins that are encoded by pathogen-induced transcripts in wheat. Using antibodies raised against a Rir1a-fusion protein we show that Rir1a is secreted from rice protoplasts transiently expressing a 35S::Rir1a construct and that the protein accumulates in the cell wall compartment of rice leaves upon inoculation with P. syringae pv. syringae. Possible roles of Rir1a in pathogen defense are discussed.

Organelle transfer by microfusion of defined protoplast-cytoplast pairs

Defined cybridization was performed by one-to-one electrofusion (microfusion) of preselected protoplast-cytoplast pairs of male-fertile, streptomycin-resistant Nicotiana tabacum and cytoplasmic male-sterile, streptomycin-sensitive N. tabacum cms (N. bigelovii), followed by microculture of the fusion products until plant regeneration. Dominant selectable markers, namely, kanamycin resistance (nptII) and hygromycin B resistance (hpt) genes had been previously integrated in the nuclear genomes of the otherwise almost fully isogenic parental strains using direct gene transfer to protoplasts. In addition to chromosome counts indicating the expected allotetraploid tobacco count of 48, the absence of the nucleus from the cytoplast donor line was confirmed by Southern blot hybridization using nptII and hpt probes, as well as by an in vitro selection test with leaf expiants and the corresponding enzyme assays for 30 cybrids. The cytoplasmic composition of the cybrids obtained was analyzed for chloroplast type using the streptomycin resistance/sensitivity locus. The fate of mitochondria in cybrids was checked by species-specific patterns in Southern analysis of restriction endonuclease digests of total DNA with N. sylvestris mitochondrial DNA probes.

Somatic hybridization by microfusion of defined protoplast pairs in Nicotiana: morphological, genetic, and molecular characterization

Somatic hybrid/cybrid plants were obtained by microfusion of defined protoplast pairs from malefertile, streptomycin-resistant Nicotiana tabacum and cytoplasmic male-sterile (cms), streptomycin-sensitive N. tabacum cms (N. bigelovii) after microculture of recovered fusants. Genetic and molecular characterization of the organelle composition of 30 somatic hybrid/cybrid plants was performed. The fate of chloroplasts was assessed by an in vivo assay for streptomycin resistance/ sensitivity using leaf explants (R0 generation and R1 seedlings). For the analysis of the mitochondrial (mt) DNA, species-specific patterns were generated by Southern hybridization of restriction endonuclease digests of total DNA and mtDNA, with three DNA probes of N. sylvestris mitochondrial origin. In addition, detailed histological and scanning electron microscopy studies on flower ontogeny were performed for representative somatic hybrids/cybrids showing interesting flower morphology. The present study demonstrates that electrofusion of individually selected pairs of protoplasts (microfusion) can be used for the controlled somatic hybridization of higher plants.