Addition of rituximab to fludarabine and cyclophosphamide in patients with chronic lymphocytic leukaemia: a randomised, open-label, phase 3 trial

BACKGROUND

On the basis of promising results that were reported in several phase 2 trials, we investigated whether the addition of the monoclonal antibody rituximab to first-line chemotherapy with fludarabine and cyclophosphamide would improve the outcome of patients with chronic lymphocytic leukaemia.

METHODS

Treatment-naive, physically fit patients (aged 30-81 years) with CD20-positive chronic lymphocytic leukaemia were randomly assigned in a one-to-one ratio to receive six courses of intravenous fludarabine (25 mg/m(2) per day) and cyclophosphamide (250 mg/m(2) per day) for the first 3 days of each 28-day treatment course with or without rituximab (375 mg/m(2) on day 0 of first course, and 500 mg/m(2) on day 1 of second to sixth courses) in 190 centres in 11 countries. Investigators and patients were not masked to the computer-generated treatment assignment. The primary endpoint was progression-free survival (PFS). Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00281918.

FINDINGS

408 patients were assigned to fludarabine, cyclophosphamide, and rituximab (chemoimmunotherapy group) and 409 to fludarabine and cyclophosphamide (chemotherapy group); all patients were analysed. At 3 years after randomisation, 65% of patients in the chemoimmunotherapy group were free of progression compared with 45% in the chemotherapy group (hazard ratio 0·56 [95% CI 0·46-0·69], p<0·0001); 87% were alive versus 83%, respectively (0·67 [0·48-0·92]; p=0·01). Chemoimmunotherapy was more frequently associated with grade 3 and 4 neutropenia (136 [34%] of 404 vs 83 [21%] of 396; p<0·0001) and leucocytopenia (97 [24%] vs 48 [12%]; p<0·0001). Other side-effects, including severe infections, were not increased. There were eight (2%) treatment-related deaths in the chemoimmunotherapy group compared with ten (3%) in the chemotherapy group.

INTERPRETATION

Chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab improves progression-free survival and overall survival in patients with chronic lymphocytic leukaemia. Moreover, the results suggest that the choice of a specific first-line treatment changes the natural course of chronic lymphocytic leukaemia.

FUNDING

F Hoffmann-La Roche.

Correlation of continuously monitored regional cerebral blood flow and brain tissue oxygen

BACKGROUND

The purpose of this study was to investigate the relationship between continuously monitored regional cerebral blood flow (CBF) and brain tissue oxygen (PtiO2).

METHODS

Continuous advanced multimodal neuromonitoring including monitoring of PtiO2 (Licox, GMS) and CBF (QFlow, Hemedex) was performed in eight patients after severe subarachnoid haemorrhage (n=5) and traumatic brain injury (n=3) for an average of 9.6 days. Parameters were measured using a flexible polarographic PtiO2-probe and a thermal diffusion CBF-microprobe.

FINDINGS

Regarding the whole monitoring period in all patients, the data indicated a significant correlation between CBF and PtiO2 (r=0.36). In 72% of 400 analysed intervals of 30 minutes duration with PtiO2 changes larger than 5 mmHg, a strong correlation between CBF and PtiO2 existed (r>0.6). In 19% of intervals a still statistically significant correlation was observed (0.3<r<0.6). During the remaining 9% no correlation was found (r<0.3). Regarding the clinical stability of the monitoring devices, the CBF monitoring system allowed monitoring of CBF in 64% of the time when PtiO2 monitoring was possible only. Phases of non-monitoring were mostly due to fever of the patient, when the system does not allow monitoring to avoid overheating of the cerebral tissue.

CONCLUSIONS

This study suggests a correlation between CBF and PtiO2. The level of PtiO2 seems to be predominately determined by regional CBF, since changes in PtiO2 were correlated in 90% of episodes to simultaneous changes of CBF.

Spot synthesis: observations and optimizations

Positionally addressable syntheses of peptides on continuous cellulose membranes (spot synthesis) have often been reported in detail, but important questions dealing with synthesis quality, reproducibility and subsequent binding assays have largely been under-emphasized. In this report we have investigated some of these problems. The most important results were: (i) the signal intensity of ligate binding to cellulose-bound peptides and the affinity of the corresponding soluble peptides show good correlation, illustrated by three different ligate binding assays; (ii) reducing peptide density on the cellulose avoids the 'ring spot' effect, i.e. where less binding is observed in the spot-center compared to the rim. We recommend a peptide density of 10 nmol/cm2 as a reasonable starting point for further optimization; (iii) statistical analysis of binding assay reproducibility with more than 15000 peptides resulted in a mean standard signal deviation of 0.18; and (iv) optimization of side-chain deprotection revealed that a 30-min pretreatment of the cellulose with 90% trifluoroacetic acid followed by the standard deprotection protocol resulted in higher purity of the synthesized products.

Revisiting adult neurogenesis and the role of erythropoietin for neuronal and oligodendroglial differentiation in the hippocampus

Recombinant human erythropoietin (EPO) improves cognitive performance in neuropsychiatric diseases ranging from schizophrenia and multiple sclerosis to major depression and bipolar disease. This consistent EPO effect on cognition is independent of its role in hematopoiesis. The cellular mechanisms of action in brain, however, have remained unclear. Here we studied healthy young mice and observed that 3-week EPO administration was associated with an increased number of pyramidal neurons and oligodendrocytes in the hippocampus of ~20%. Under constant cognitive challenge, neuron numbers remained elevated until >6 months of age. Surprisingly, this increase occurred in absence of altered cell proliferation or apoptosis. After feeding a ¹⁵N-leucine diet, we used nanoscopic secondary ion mass spectrometry, and found that in EPO-treated mice, an equivalent number of neurons was defined by elevated ¹⁵N-leucine incorporation. In EPO-treated NG2-Cre-ERT2 mice, we confirmed enhanced differentiation of preexisting oligodendrocyte precursors in the absence of elevated DNA synthesis. A corresponding analysis of the neuronal lineage awaits the identification of suitable neuronal markers. In cultured neurospheres, EPO reduced Sox9 and stimulated miR124, associated with advanced neuronal differentiation. We are discussing a resulting working model in which EPO drives the differentiation of non-dividing precursors in both (NG2+) oligodendroglial and neuronal lineages. As endogenous EPO expression is induced by brain injury, such a mechanism of adult neurogenesis may be relevant for central nervous system regeneration.

Phosphorylation of Ser-42 and Ser-59 in the N-terminal region of the tyrosine kinase p56lck

Ser-42 and Ser-59 in the N-terminal region have been identified as the major phorbol ester-induced phosphorylation sites of p56lck. Phosphorylation of Ser-59 results in a gel shift from 56 kDa to 61 kDa. Simultaneous phosphorylation of Ser-42 and Ser-59 results in a further gel shift to 63 kDa. In vitro kinase assays show that Ser-59 can be uniquely phosphorylated by mitogen-activated protein kinase and that Ser-42 can be phosphorylated by either protein kinase A or protein kinase C.

Global decrease of serotonin-1A receptor binding after electroconvulsive therapy in major depression measured by PET

Electroconvulsive therapy (ECT) is a potent therapy in severe treatment-refractory depression. Although commonly applied in psychiatric clinical routine since decades, the exact neurobiological mechanism regarding its efficacy remains unclear. Results from preclinical and clinical studies emphasize a crucial involvement of the serotonin-1A receptor (5-HT(1A)) in the mode of action of antidepressant treatment. This includes associations between treatment response and changes in 5-HT(1A) function and density by antidepressants. Further, alterations of the 5-HT(1A) receptor are consistently reported in depression. To elucidate the effect of ECT on 5-HT(1A) receptor binding, 12 subjects with severe treatment-resistant major depression underwent three positron emission tomography (PET) measurements using the highly selective radioligand [carbonyl-(11)C]WAY100635, twice before (test-retest variability) and once after 10.08±2.35 ECT sessions. Ten patients (~83%) were responders to ECT. The voxel-wise comparison of the 5-HT(1A) receptor binding (BP(ND)) before and after ECT revealed a widespread reduction in cortical and subcortical regions (P<0.05 corrected), except for the occipital cortex and the cerebellum. Strongest reductions were found in regions consistently reported to be altered in major depression and involved in emotion regulation, such as the subgenual part of the anterior cingulate cortex (-27.5%), the orbitofrontal cortex (-30.1%), the amygdala (-31.8%), the hippocampus (-30.6%) and the insula (-28.9%). No significant change was found in the raphe nuclei. There was no significant difference in receptor binding in any region comparing the first two PET scans conducted before ECT. This PET study proposes a global involvement of the postsynaptic 5-HT(1A) receptor binding in the effect of ECT.

A polymorphism (5-HTTLPR) in the serotonin transporter promoter gene is associated with DSM-IV depression subtypes in seasonal affective disorder

Serotonergic mechanisms are thought to play an important role in the pathogenesis of seasonal affective disorder (SAD). The expression of the serotonin transporter (5-HTT) is regulated in part by an insertion/deletion polymorphism in the serotonin transporter gene promoter region (5-HTTLPR). The 5-HTTLPR short allele (s) has been associated with anxiety-related personality traits and depression, and one study observed an association between the 5-HTTLPR s-allele and SAD and the trait of seasonality. We genotyped 138 SAD patients and 146 healthy volunteers with low seasonality for 5-HTTLPR. No difference between patients and controls was found for genotype distribution and s-allele frequency. However, genotype distribution and allele frequencies were strongly associated with DSM-IV depression subtypes. Melancholic depression was associated with the 5-HTTLPR long (l) allele and atypical depression with the 5-HTTLPR s-allele (two-sided Fisher's exact test: genotype distribution: P=0.0038; allele frequencies: P=0.007). Our data are compatible with the hypothesis of a disease process that is not causally related to 5-HTTLPR, but involves 5-HT neurotransmission and 5-HTTLPR somewhere on its way to phenotypic disease expression.

The first evaluation of brain shift during functional neurosurgery by deformation field analysis

Stereotactic surgery is based on a high degree of accuracy in defining and localising intracranial targets and placing surgical tools. Brain shift can influence its accuracy significantly. Deep brain stimulation of the subthalamic nucleus can markedly change the quality of life of patients with advanced Parkinson's disease, but the outcome depends on the quality of electrode placement. A patient is reported in whom the placement of the second electrode was not successful. Deformation field analysis of pre- and postoperative three dimensional magnetic resonance images showed an intraoperative brain movement of 2 mm in the region of the subthalamic nucleus (the target point). Electrode repositioning resulted in efficient stimulation effects. This case report shows the need to reduce risk factors for intraoperative brain movement and demonstrates the ability of deformation field analysis to quantify this complication.

Purification and characterization of a soluble catalytic fragment of the human transmembrane leukocyte antigen related (LAR) protein tyrosine phosphatase from an Escherichia coli expression system

A 350 amino acid soluble fragment of the intracellular catalytic domain of the human transmembrane leukocyte antigen related (LAR) protein tyrosine phosphatase has been purified 17-fold to greater than 90% purity from an Escherichia coli expression vector in quantities sufficient for kinetic and structural characterization. To assess substrate specificity, phosphotyrosine peptides corresponding to autophosphorylation sites of the two major classes of tyrosine kinases have been synthesized. Thus 6-12-residue phosphotyrosine peptides of the insulin receptor and epidermal growth factor receptor kinase domains and of the autophosphorylation and C-terminal regulatory sites of p60src and p56lck have been analyzed for kcat and KM by using a nonradioactive chromogenic assay for Pi release. The catalytic domain of LAR PTPase shows kcat values of 20-70 s-1 for phosphotyrosine peptides and affinities that vary 150-fold from 27 microM to 4.1 mM.

Treatment of tumours of the pineal region and posterior part of the third ventricle

The evaluation of tumours located in the posterior part of the third ventricle or pineal region is achieved best by magnet resonance imaging (MRI). It shows the exact localization and extent, the involvement of neighbouring structures like thalamus or quadrigeminal plate and the displacement of the large veins, the internal cerebral veins, the vein of Galen and the veins of Rosenthal. If only CT is available, angiography should be performed prior to operation to identify the course of the veins. In children with a pineal region tumour the "tumour markers" AFP and beta-HCG should be determined before operation. We approach the rare tumours entirely located within the posterior part of the third ventricle by the posterior interhemispheric transcallosal route with the patient in prone position with the head elevated. The same approach is used for pineal region tumours extending above the internal cerebral veins. Tumours arising from the posterior thalamus extending into the thalamus and ventricle as well, are better approached by the posterior transcortical transventricular route since the lateral view is rather limited by the midline approach. The most frequent tumours in the pineal region are approached if they are located below the internal veins by the infratentorial, supracerebellar route in the sitting position. A total of 60 cases are evaluated. If AFP and/or beta-HCG are positive a highly malignant nongerminomatous germ-cell tumour must be suspected. We recommend initial chemotherapy with a combination of Vinblastine, Ifosfamide and Cis-platin without biopsy to avoid tumour seeding. After the "markers" are normalized operative removal of the residual tumour and radiotherapy should be carried out. In a series of 13 children operated on for pineal region tumours a rigid neuropsychological and endocrine evaluation was performed with encouraging results. During the last 10 years we have performed 49 open operations and 11 stereotactic biopsies. 40% of the patients were children under the age of 18. 40% of the tumours in childhood and 60% in adults were benign. In childhood 24% were germinomas and 20% non-germinomatous germ cell tumours.

Chronic vagus nerve stimulation increases the latency of the thalamocortical somatosensory evoked potential

The Neurocybernetic Prosthesis (NCP) is a pacemaker-like device that has been designed to provide chronic intermittent vagus nerve stimulation. It is currently under study for the treatment of refractory partial onset epilepsy, and preliminary studies have indicated that partial onset seizures are improved by this therapy. The mechanisms by which it exerts its antiepileptic effect are not well understood. Although there are extensive pathways to the forebrain from the nuclei of the vagus nerve, the evidence that the NCP alters neural transmission outside the vagal system is limited. We prospectively examined somatosensory and brain stem auditory evoked potentials (BAEPs) in three patients receiving NCP implantation to determine if changes in these studies occur as a result of chronic vagus nerve stimulation. The results demonstrate a significant prolongation of the cervicomedullary to thalamocortical potential (N13-N20) interval on somatosensory evoked potential (SSEP) studies following activation of the device. No other significant changes were seen on SSEP or BAEP in the NCP implanted patients or normal controls. The findings suggest that chronic vagus nerve stimulation does alter neuronal networks outside of the brain stem vagus system, and may potentially provide a means to clinically monitor and titrate this therapy.

Intramedullary spinal cord tumors resected with CO2 laser microsurgical technique: recent experience in fifteen patients

We have operated upon 15 intramedullary spinal cord tumors with the aid of a CO2 laser attached to the microscope. The operative technique is described. Most of the tumors were localized within the cervical spinal cord. Nine tumors were benign gliomas: 4 ependymomas, 1 subependymoma, 3 astrocytomas, and 1 ganglioglioma. Six were removed totally, and 3 were removed subtotally. The remaining 6 tumors consisted of 3 hemangioblastomas, 1 intramedullary neurofibroma, 1 lipoma, and 1 primary intramedullary melanoma. Neurological function postoperatively compared to the preoperative function of the upper extremities was unchanged in 13 patients (86.5%), improved in 1, and worse in 1 patient. In the lower extremities, the preoperative neurological status was unchanged in 11 patients (73.3%), improved in 1 patient, and worse in 3 patients (20%). Magnetic resonance imaging was superior to myelography and computed tomography in localizing these lesions. Enhancement with paramagnetic substances (e.g., gadolinium-DTPA) helps to localize solid tumor within cysts. Histological evaluation of small tissue biopsies or frozen section histology is unreliable. The entire lesion should be exposed in all cases, and an attempt should be made to remove the tumor totally or, if this is not possible, to resect as much of the center of the tumor as is possible until the cord is decompressed. The decision to administer further treatment is based on the histological features of the tumor.

Modification of Ser59 in the unique N-terminal region of tyrosine kinase p56lck regulates specificity of its Src homology 2 domain

During T-cell activation, Ser59 in the unique N-terminal region of p56lck is phosphorylated. Mutation of Ser59 to Glu59 mimics Ser59 phosphorylation, and upon CD4 crosslinking, this mutant p56lck induces tyrosine phosphorylation of intracellular proteins distinct from those induced by wild-type p56lck. Mutant and wild-type p56lck have similar affinities for CD4 and similar kinase activities. In glutathione S-transferase fusion proteins, the p56lck Src homology 2 (SH2) domain with the SH3 domain and the unique N-terminal region (including Ser59) has a different binding specificity for phosphotyrosyl proteins than the SH2 domain alone. Either deletion of the unique N-terminal region or mutation of Ser59 to Glu59 in the fusion protein reverts the phosphotyrosyl protein binding specificity back to that of the SH2 domain alone. These results suggest that phosphorylation of Ser59 regulates the function of p56lck by controlling binding specificity of its SH2 domain.

Identification of residues in the cysteine-rich domain of Raf-1 that control Ras binding and Raf-1 activity

We have identified mutations in Raf-1 that increase binding to Ras. The mutations were identified making use of three mutant forms of Ras that have reduced Raf-1 binding (Winkler, D. G., Johnson, J. C., Cooper, J. A., and Vojtek, A. B. (1997) J. Biol. Chem. 272, 24402-24409). One mutation in Raf-1, N64L, suppresses the Ras mutant R41Q but not other Ras mutants, suggesting that this mutation structurally complements the Ras R41Q mutation. Missense substitutions of residues 143 and 144 in the Raf-1 cysteine-rich domain were isolated multiple times. These Raf-1 mutants, R143Q, R143W, and K144E, were general suppressors of three different Ras mutants and had increased interaction with non-mutant Ras. Each was slightly activated relative to wild-type Raf-1 in a transformation assay. In addition, two mutants, R143W and K144E, were active when tested for induction of germinal vesicle breakdown in Xenopus oocytes. Interestingly, all three cysteine-rich domain mutations reduced the ability of the Raf-1 N-terminal regulatory region to inhibit Xenopus oocyte germinal vesicle breakdown induced by the C-terminal catalytic region of Raf-1. We propose that a direct or indirect regulatory interaction between the N- and C-terminal regions of Raf-1 is reduced by the R143W, R143Q, and K144E mutations, thereby increasing access to the Ras-binding regions of Raf-1 and increasing Raf-1 activity.

Cross-reactive binding of cyclic peptides to an anti-TGFalpha antibody Fab fragment: an X-ray structural and thermodynamic analysis

The monoclonal antibody tAb2 binds the N-terminal sequence of transforming growth factor alpha, VVSHFND. With the help of combinatorial peptide libraries it is possible to find homologous peptides that bind tAb2 with an affinity similar to that of the epitope. The conformational flexibility of short peptides can be constrained by cyclization in order to improve their affinity to the antibody and their stability towards proteolysis. Two cyclic peptides which are cross-reactive binders for tAb2 were selected earlier using combinatorial peptide libraries. One is cyclized by an amide bond between the N-alpha group and the side-chain of the last residue (cyclo-SHFNEYE), and the other by a disulfide bridge (cyclo-CSHFNDYC). The complex structures of tAb2 with the linear epitope peptide VVSHFND and with cyclo-SHFNEYE were determined by X-ray diffraction. Both peptides show a similar conformation and binding pattern in the complex. The linear peptide SHFNEYE does not bind tAb2, but cyclo-SHFNEYE is stabilized in a loop conformation suitable for binding. Hence the cyclization counteracts the exchange of aspartate in the epitope sequence to glutamate. Isothermal titration calorimetry was used to characterize the binding energetics of tAb2 with the two cyclic peptides and the epitope peptide. The binding reactions are enthalpically driven with an unfavorable entropic contribution under all measured conditions. The association reactions are characterized by negative DeltaC(p) changes and by the uptake of one proton per binding site. A putative candidate for proton uptake during binding is the histidine residue in each of the peptides. Hydrogen bonds and the putative formation of an electrostatic pair between the protonated histidine and a carboxy group may contribute markedly to the favorable enthalpy of complex formation. Implications to cyclization of peptides for stabilization are discussed.

Epidemiology and socioeconomic impact of seasonal affective disorder in Austria

BACKGROUND

Seasonal affective disorder (SAD) is a subtype of recurrent depressive or bipolar disorder that is characterized by regular onset and remission of affective episodes at the same time of the year. The aim of the present study was to provide epidemiological data and data on the socioeconomic impact of SAD in the general population of Austria.

METHODS

We conducted a computer-assisted telephone interview in 910 randomly selected subjects (577 females and 333 males) using the Seasonal Health Questionnaire (SHQ), the Seasonal Pattern Assessment Questionnaire (SPAQ), and the Sheehan Disability Scale (SDS). Telephone numbers were randomly drawn from all Austrian telephone books and transformed using the random last digits method. The last birthday method was employed to choose the target person for the interviews.

RESULTS

Out of our subjects, 2.5% fulfilled criteria for the seasonal pattern specifier according to DSM-5 and 2.4% (95% CI=1.4-3.5%) were diagnosed with SAD. When applying the ICD-10 criteria 1.9% (95% CI=0.9-2.8%) fulfilled SAD diagnostic criteria. The prevalence of fall-winter depression according to the Kasper-Rosenthal criteria was determined to be 3.5%. The criteria was fulfilled by 15.1% for subsyndromal SAD (s-SAD). We did not find any statistically significant gender differences in prevalence rates. When using the DSM-5 as a gold standard for the diagnosis of SAD, diagnosis derived from the SPAQ yielded a sensitivity of 31.8% and a specificity of 97.2%. Subjects with SAD had significantly higher scores on the SDS and higher rates of sick leave and days with reduced productivity than healthy subjects.

CONCLUSIONS

Prevalence estimates for SAD with the SHQ are lower than with the SPAQ. Our data are indicative of the substantial burden of disease and the socioeconomic impact of SAD. This epidemiological data shows a lack of gender differences in SAD prevalence. The higher rates of females in clinical SAD samples might, at least in part, be explained by lower help seeking behaviour in males.

Association of Protein Distribution and Gene Expression Revealed by PET and Post-Mortem Quantification in the Serotonergic System of the Human Brain

Regional differences in posttranscriptional mechanisms may influence in vivo protein densities. The association of positron emission tomography (PET) imaging data from 112 healthy controls and gene expression values from the Allen Human Brain Atlas, based on post-mortem brains, was investigated for key serotonergic proteins. PET binding values and gene expression intensities were correlated for the main inhibitory (5-HT1A) and excitatory (5-HT2A) serotonin receptor, the serotonin transporter (SERT) as well as monoamine oxidase-A (MAO-A), using Spearman's correlation coefficients (rs) in a voxel-wise and region-wise analysis. Correlations indicated a strong linear relationship between gene and protein expression for both the 5-HT1A (voxel-wise rs = 0.71; region-wise rs = 0.93) and the 5-HT2A receptor (rs = 0.66; 0.75), but only a weak association for MAO-A (rs = 0.26; 0.66) and no clear correlation for SERT (rs = 0.17; 0.29). Additionally, region-wise correlations were performed using mRNA expression from the HBT, yielding comparable results (5-HT1Ars = 0.82; 5-HT2Ars = 0.88; MAO-A rs = 0.50; SERT rs = -0.01). The SERT and MAO-A appear to be regulated in a region-specific manner across the whole brain. In contrast, the serotonin-1A and -2A receptors are presumably targeted by common posttranscriptional processes similar in all brain areas suggesting the applicability of mRNA expression as surrogate parameter for density of these proteins.

Changes of clinical pattern in seasonal affective disorder (SAD) over time in a German-speaking sample

OBJECTIVE

The goals of this study are to provide estimates of clinical and demographic variables of patients with seasonal affective disorder (SAD) in Germany and Austria, to compare our results with those of previously published SAD studies, and to find out whether the clinical pattern of SAD remained stable over several years.

METHOD

We investigated 610 SAD patients from the outpatient clinics in Bonn (n = 190) and Vienna (n = 420). Patients in Bonn were recruited in the fall-winter season of the years 1989-1992, those in Vienna in the years 1993-2001.

RESULTS

We observed a change in the clinical pattern in our patients: patients from Bonn, who were diagnosed and treated about 5 years earlier, were more likely to suffer from melancholic depression, whereas Viennese patients rather suffered from atypical depression (chi(2) = 54.952, df = 2, p < 0.001). The symptoms of hypersomnia, daytime fatigue, increased eating and carbohydrate-craving were more frequent in the Viennese sample, anxiety and deterioration of patients' capacity to perform at work predominated in Bonn. In addition, patients from Vienna obtained a higher GSS (global seasonality score, measured by the SPAQ - Seasonal Pattern Assessment Questionnaire) than those from Bonn (15.7 +/- 3.3 and 14.6 +/- 4.1 respectively; t = 3.104, p = 0.002). Taken together, our results were in good accordance to other published SAD materials, but we were able to demonstrate that our patients reported "feeling worst" (measured by item 13H of the SPAQ) in November and December, whereas SAD patients in the USA clearly had their worst months in January and February.

CONCLUSIONS

We suggest that an increase in awareness of fall-winter depression in the last decade by both doctors, who referred patients, as well as patients or the entire population must have caused patients to sign up for light therapy at the Viennese SAD clinic because of having heard about the atypical symptom profile. This increased awareness of SAD can also be measured by a statistically significant reduction in the diagnostic latency (from the age of onset to the diagnosis of SAD) when comparing the two study locations.

Purification and initial characterization of the lymphoid-cell protein-tyrosine kinase p56lck from a baculovirus expression system

The lymphocyte-specific protein-tyrosine kinase p56lck has been purified 90-fold to approximately 30% purity in 30% yield from a baculovirus expression system by a two-column purification procedure. At least two forms of p56lck were isolated, differing in the extent of phosphorylation and migrating as 56- and 59-kDa species on SDS/PAGE but as a single 56-kDa band after treatment with potato acid phosphatase. Autophosphorylation of purified p56lck occurred at a rate of 25 fmol/min to a maximum incorporation of approximately 2 mol of phosphate per mol of p56lck with tyrosine-394 (but not tyrosine-505) and other, unidentified tyrosine residue(s) being the major sites of phosphorylation in vitro. Phosphorylation of tyrosine-containing peptides was monitored using an automated HPLC system. Although peptide substrate Km values were in the 1-5 mM range, the Vmax for the 13-amino acid peptide RRLIEDAEYAARG (modified p60src autophosphorylation site) was 120 min-1 (350 min-1 when adjusted for p56lck purity), suggesting that the enzyme purified from recombinant baculovirus-infected Sf9 cells has a high catalytic turnover compared with other tyrosine kinases.

Identification and characterization of mutations in Ha-Ras that selectively decrease binding to cRaf-1

The oncoprotein Ras transforms cells by binding to one or more effector proteins. Effector proteins have been identified by their ability to bind to Ras in the GTP but not GDP form, and by their requirement for the Ras effector domain for binding. The best understood Ras effectors are serine/threonine kinases of the Raf family, but other candidate Ras effectors, including a Ral guanine nucleotide dissociation stimulator and phosphatidylinositol 3-kinase (PI3 kinase) have also been identified. To investigate the mechanism of binding of cRaf-1 to Ras, and to investigate the roles of other candidate Ras effectors in transformation, we have isolated and characterized mutants of activated Ras with decreased binding to cRaf-1 relative to other candidate effectors. Examination of these mutants indicates that surface-exposed residues of Ras outside the minimal effector domain interact differentially with cRaf-1 and other Ras-binding proteins, and that fibroblast transformation correlates with cRaf-1 binding and mitogen-activated protein (MAP) kinase activation. Furthermore, activation of PI3 kinase can occur in the absence of significant MAP kinase activation, suggesting that PI3 kinase activation is a primary effect of Ras.

[Manipulator assisted endoscope guidance in functional endoscopic sinus surgery: proof of concept]

BACKGROUND

Functional endoscopic sinus surgery (FESS) is characterized by single-handed preparation and guidance of the endoscope by the nondominant hand. This results in an additional extension of operation time by up to 15% and ergonomic deficits. The aim of this study is the conception of an automated assistance system for FESS in view of the following questions: (1) Which degree of surgical automation is suitable for FESS? (2) Which design is suitable? (3) What are the properties of the technical system (planning, time, accuracy, precision) of the selected system? (4) Does the system offer potential for a clinical application?

METHODS

In all 49 FESS were analyzed for surgical workflows. Measurement of the maximum forces within FESS was performed with 40 trials on an anatomical model. Three different mechanical systems were used in ten FESS and evaluated using the ICCAS Human-Machine Evaluation Scale. For realization of automated endoscope guidance an engine-driven and -braked manipulator (PA10-6c, Mitsubishi, Japan) was used. The technical parameters determined were expenditure of time for the preoperative planning of workspace, surgical accuracy and precision of the intraoperative endoscope positioning, maximal forces, and time.

RESULTS

Concept-conditioned instrument changes amount to an average of 41.1 and 18.9% (5.21 min) time requirement for each FESS side. Maximum forces on the mucous membrane during a conventional FESS were measured at 9.8 N (5.9-9.8). Usability of the mechanical endoscope holder was estimated in 18 of 20 cases to be inferior to the standard procedure. The time needed for segmenting the intranasal workspace was 15.2 min (10.0-23.0). The maximum deviation of the automatically driven endoscope from a planned position amounted to 0.85 mm (manually 4.64 mm). The maximum force was measured with 1.1 N in the z direction (manually 9.8 N). Automated guidance of the endoscope to an intranasal position needed 7.25 s (6.4-7.9); manually 12.64 s (5.9-43.0).

CONCLUSION

Guidance of the endoscope for FESS by an automated motor-driven system is possible. The conception which is based on workflow analysis favors a system with automatic definition of the workspace and a manual movement of the endoscope. The examined system offers a potential for clinical application. Definition of the automation level and development of a man-machine interface is more important than selection or reconstruction of a special manipulator for endoscope guidance in FESS from a surgical point of view.

[Fusion of MRI, fMRI and intraoperative MRI data. Methods and clinical significance exemplified by neurosurgical interventions]

The aim of this work was to realize and clinically evaluate an image fusion platform for the integration of preoperative MRI and fMRI data into the intraoperative images of an interventional MRI system with a focus on neurosurgical procedures. A vertically open 0.5 T MRI scanner was equipped with a dedicated navigation system enabling the registration of additional imaging modalities (MRI, fMRI, CT) with the intraoperatively acquired data sets. These merged image data served as the basis for interventional planning and multimodal navigation. So far, the system has been used in 70 neurosurgical interventions (13 of which involved image data fusion--requiring 15 minutes extra time). The augmented navigation system is characterized by a higher frame rate and a higher image quality as compared to the system-integrated navigation based on continuously acquired (near) real time images. Patient movement and tissue shifts can be immediately detected by monitoring the morphological differences between both navigation scenes. The multimodal image fusion allowed a refined navigation planning especially for the resection of deeply seated brain lesions or pathologies close to eloquent areas. Augmented intraoperative orientation and instrument guidance improve the safety and accuracy of neurosurgical interventions.