Radiation dose intensification in pre-operative chemo-radiotherapy for locally advanced rectal cancer.

BACKGROUND: To assess the role of radiation dose intensification with simultaneous integrated boost guided by 18-FDG-PET/CT in pre-operative chemo-radiotherapy (ChT-RT) for locally advanced rectal cancer. METHODS: A prospective study was approved by the Internal Review Board. Inclusion criteria were: age >18 years old, World Health Organization performance status of 0-1, locally advanced histologically proven adenocarcinoma of the rectum within 10 cm of the anal verge, signed specific informed consent. High-dose volumes were defined including the hyper-metabolic areas of 18-FDG-PET/CT of primary tumor and the corresponding mesorectum and/or pelvic nodes with at least a standardized uptake values (SUV) of 5. A dose of 60 Gy/30 fractions was delivered. A total dose of 54 Gy/30 fractions was delivered to prophylactic areas. Capecitabine was administered concomitantly with RT for a dose of 825 mg/mq twice daily for 5 days/every week. RESULTS: Between September 2011 and July 2015 fortypatients were recruited. At the time of the analysis, median follow up was 20 months (range 5-51). The median interval from the end of ChT-RT to surgery was 9 weeks (range 8-12). Thirty-seven patients (92.5 %) were submitted to sphincter preservation. Tumor Regression Grade (Mandard scale) was recorded as follows: grade 1 in 7 (17.5 %), grade 2 in 17 (42.5 %), grade 3 in 15 (37.5 %) and grade 4 in 1 (2.5 %). Post-surgical circumferential resection margin was negative in all patients. A tumor downstaging was reported in 62.5 % (95 % CI: 0.78-0.47). A nodes downstaging was registered in 85 % (95 % CI: 0.55-0.25). 18-FDG-PET/CT was not able to predict pCR. No correlation was found between pre-treatment SUV-max values and pCR. A metabolic tumor volume >127 cc was related to ypT ≥2 (p 0.01). Patients with TRG >2 had higher tumor lesion glycolysis values (p 0.05). CONCLUSION: Preliminary results did not confirm some advantages in terms of primary tumor downstaging/downsizing compared to conventional schedules reported in historical series. The role of 18-FDG-PET/CT in neoadjuvant rectal cancer management needs to be confirmed in further investigations. Long terms results are necessary.

Applying radiobiological plan ranking methodology to VMAT prostate SBRT.

The impact of a rectal spacer and an increased near maximum target dose in VMAT prostate SBRT is studied. For a group of 11 patients (35Gy-in-five-fractions VMAT prostate SBRT) a set of 4 plans were generated, namely two VMAT plans, with D2%⩽37.5Gy (Hom) and with D2%⩽40.2Gy (Het), were created for each of two CT scans taken before (NoSpc) and after (Spc) transperineal spacer insertion. Consequently the methodology for parameter invariant TCP (tumor control probability) plan ranking was applied for comparison of the plans in terms of tumor control. NTCPs (normal tissue complication probabilities) were calculated for rectum and bladder using Lyman's model. For all 11 patients the TCP plan ranking has shown that the Het plans would perform considerably better in TCP terms than the Hom ones. The plans without rectal spacer were ranked worse compared to those with rectal spacer except for one set of Hom plans. The calculated NTCPs for rectum produced by the Het plans were quite similar to the NTCPs of the Hom ones. The rectal NTCPs of the Hom Spc plans were always lower than the NTCPs of the Hom NoSpc plans. The NTCP values for bladder were extremely low in all cases. The use of rectal spacer leads in general to lower risk of rectal complications, as expected, and even to better tumor control. Plans with increased near maximum target dose (D2%⩽40.2Gy) are expected to perform much better in terms of tumor control than those with D2%⩽37.5Gy.

Cachexia induces head and neck changes in locally advanced oropharyngeal carcinoma during definitive cisplatin and image-guided volumetric-modulated arc radiation therapy.

BACKGROUND/OBJECTIVES: Cancer cachexia is a syndrome characterized by weight loss (WL) and sarcopenia. Aim of the study was to assess the impact of cachexia on head and neck changes during definitive cisplatin and image-guided volumetric-modulated arc radiation therapy in a series of locally advanced oropharyngeal cancer. SUBJECTS/METHODS: Volume variations of sternocleidomastoid muscle (SCM) were considered as surrogate of muscle changes related to sarcopenia. Two head and neck diameters, encompassing the cranial limits of II and III nodal levels (defined as 'head diameter' and 'neck diameter', respectively), were measured. All parameters were defined retrospectively by means of on-board cone beam computed tomography images at 1-8th to 15-22th and at last fraction (fx) of radiotherapy (RT). Cachexia was defined as WL >5% during treatment. Analysis was conducted correlating the parameter changes with three WL ranges: <5, 5-9 and>10%. RESULTS: Thirty patients were evaluated. One hundred and fifty contoured SCMs and three hundred diameters were collected. Median WL was 6.5% (range, 0-16%). The most significant SCM shrinkage was recorded at 15th fx (mean 1.6 cc) related to WL 5-9% and WL >10% (P 0.001). For 'head diameter', the peak reduction was recorded at the 15th fx (mean 8 mm), statistically correlated to WL >10% (P 0.001). The peak reduction in 'neck diameter' was registered at the 22th fx (mean 6 mm), with a gradual reduction until the end of treatment for WL >5%. CONCLUSIONS: In a homogeneous cohort of patients, present study quantified the impact of cachexia on head and neck changes. Present data could provide adaptive RT implications for further investigations.

The impact of prostate gland dimension in genitourinary toxicity after definitive prostate cancer treatment with moderate hypofractionation and volumetric modulated arc radiation therapy.

PURPOSE: To analyze clinical-dosimetric predictors of genitourinary (GU) toxicity in a cohort of prostate cancer (PC) patients treated with moderate hypofractionation and simultaneous integrated boost (SIB) using volumetric modulated arc therapy (VMAT) technique. MATERIALS AND METHODS: 60 patients were selected. Patients were stratified into low (43 %), intermediate (30 %) and high-risk (27 %) groups. Low-risk patients received 73.5 Gy to PTV1; intermediate-risk received 73.5 Gy to PTV1 and 60 Gy to PTV2; high-risk received 73.5 Gy to PTV1, 60 Gy to PTV2, and 54 Gy to PTV3. All patients were treated in 30 fractions. Androgen deprivation therapy (ADT) was prescribed upfront in intermediate and high-risk categories. Toxicity was scored according to Common Terminology Criteria for Adverse Events v4.0 scoring system. RESULTS: Median follow-up was 30 months (range 16-36 months). GU acute toxicity was recorded as followS: G0 = 16/60 (27 %), G1 = 18/60 (30 %); G2 = 26/60 (43 %). GU late toxicity was recorded as follows: G0 = 20/60 (34 %); G1 = 29/60 (48 %); G2 = 11/56 (18 %). The risk of acute G2 GU toxicity was three times higher for prostate volume ≥80 cc. In 60 % of the patients with a prostate volume ≥80 cc, the first 3 weeks are at particular risk for toxicity onset. In the late setting, no statistical significance was found between GU toxicity and prostate gland dimension. CONCLUSION: Prostate volume ≥80 cc resulted a predictive factor of acute G2 GU toxicity, in moderate hypofractionation and volumetric modulated arc radiation therapy for definitive PC.

The MAP3K ZAK, a novel modulator of ERK-dependent migration, is upregulated in colorectal cancer.

Often described as a mediator of cell cycle arrest or as a pro-apoptotic factor in stressful conditions, the MAP3K ZAK (Sterile alpha motif and leucine zipper-containing kinase) has also been proven to positively regulate epidermal growth factor receptor (EGFR) and WNT signaling pathways, cancer cell proliferation and cellular neoplastic transformation. Here, we show that both isoforms of ZAK, ZAK-α and ZAK-ß are key factors in cancer cell migration. While ZAK depletion reduced cell motility of HeLa and HCT116 cells, its overexpression triggered the activation of all three mitogen-activated protein kinases (MAPKs), extracellular signal-regulated kinase (ERK), c-JUN N-terminal kinase (JNK) and p38, as well as an increase in cell motion. On the contrary, the kinase-dead mutants, ZAK-α K45M and ZAK-ß K45M, were not able to provoke such events, and instead exerted a dominant-negative effect on MAPK activation and cell migration. Pharmacological inhibition of ZAK by nilotinib, preventing ZAK-autophosphorylation and thereby auto-activation, led to the same results. Activated by epidermal growth factor (EGF), we further showed that ZAK constitutes an essential element of the EGF/ERK-dependent cell migration pathway. Using public transcriptomic databases and tissue microarrays, we finally established that, as strong factors of the EGFR signaling pathway, ZAK-α and/or ZAK-ß transcripts and protein(s) are frequently upregulated in colorectal adenoma and carcinoma patients. Notably, gene set enrichment analysis disclosed a significant correlation between ZAK+ colorectal premalignant lesions and gene sets belonging to the MAPK/ERK and motility-related signaling pathways of the reactome database, strongly suggesting that ZAK induces such pro-tumoral reaction cascades in human cancers.

Intensity modulated radiation therapy with simultaneous integrated boost in early breast cancer irradiation. Report of feasibility and preliminary toxicity.

PURPOSE: To investigate the feasibility and tolerance in the use of adjuvant intensity modulated radiation therapy (IMRT) and simultaneous integrated boost in patients with a diagnosis of breast cancer after breast-conserving surgery. PATIENTS AND METHODS: Between September 2011 to February 2013, 112 women with a diagnosis of early breast cancer (T1-2, N0-1, M0) were treated with IMRT and simultaneous integrated boost after breast-conserving surgery in our institution. A dose of 50Gy in 25 fractions was prescribed to the whole breast and an additional dose of radiation was prescribed on the tumour bed. A dose prescription of 60Gy in 25 fractions to the tumour bed was used in patients with negative margins after surgery, whereas if the margins were close (<1mm) or positive (without a new surgical resection) a dose of 64Gy was prescribed. All patients were followed with periodic clinical evaluation. Acute and late toxicity were scored using the EORTC/RTOG radiation morbidity score system. Both patient and physician recorded cosmetic outcome evaluation with a subjective judgment scale at the time of scheduled follow-up. RESULTS: The median follow-up was 28 months (range 24-40 months). The acute skin grade toxicity during the treatment was grade 0 in 8 patients (7%), grade 1 in 80 (72%), grade 2 in 24 cases (21%). No grade 3 or higher acute skin toxicity was observed. At 12 months, skin toxicity was grade 0 in 78 patients (70%), grade 1 in 34 patients (30%). No toxicity grade 2 or higher was registered. At 24 months, skin toxicity was grade 0 in 79 patients (71%), grade 1 in 33 patients (29%). No case of grade 2 toxicity or higher was registered. The pretreatment variables correlated with skin grade 2 acute toxicity were adjuvant chemotherapy (P=0.01) and breast volume ≥700cm(3) (P=0.001). Patients with an acute skin toxicity grade 2 had a higher probability to develop late skin toxicity (P<0.0001). In the 98% of cases, patients were judged to have a good or excellent cosmetic outcome. The 2-year-overall survival and 2-year-local control were 100%. CONCLUSION: These data support the feasibility and safety of IMRT with simultaneous integrated boost in patients with a diagnosis of early breast cancer following breast-conserving surgery with acceptable acute and late treatment-related toxicity. A longer follow-up is needed to define the efficacy on outcomes.

Dose-volume-related dysphagia after constrictor muscles definition in head and neck cancer intensity-modulated radiation treatment.

OBJECTIVE: Dysphagia remains a side effect influencing the quality of life of patients with head and neck cancer (HNC) after radiotherapy. We evaluated the relationship between planned dose involvement and acute and late dysphagia in patients with HNC treated with intensity-modulated radiation therapy (IMRT), after a recontouring of constrictor muscles (PCs) and the cricopharyngeal muscle (CM). METHODS: Between December 2011 and December 2013, 56 patients with histologically proven HNC were treated with IMRT or volumetric-modulated arc therapy. The PCs and CM were recontoured. Correlations between acute and late toxicity and dosimetric parameters were evaluated. End points were analysed using univariate logistic regression. RESULTS: An increasing risk to develop acute dysphagia was observed when constraints to the middle PCs were not respected [mean dose (Dmean) ≥50 Gy, maximum dose (Dmax) >60 Gy, V50 >70% with a p = 0.05]. The superior PC was not correlated with acute toxicity but only with late dysphagia. The inferior PC was not correlated with dysphagia; for the CM only, Dmax >60 Gy was correlated with acute dysphagia ≥ grade 2. CONCLUSION: According to our analysis, the superior PC has a major role, being correlated with dysphagia at 3 and 6 months after treatments; the middle PC maintains this correlation only at 3 months from the beginning of radiotherapy, but it does not have influence on late dysphagia. The inferior PC and CM have a minimum impact on swallowing symptoms. ADVANCES IN KNOWLEDGE: We used recent guidelines to define dose constraints of the PCs and CM. Two results emerge in the present analysis: the superior PC influences late dysphagia, while the middle PC influences acute dysphagia.

Guanine nucleotide exchange factor Dock7 mediates HGF-induced glioblastoma cell invasion via Rac activation.

BACKGROUND: Glioblastoma multiforme (GBM), a highly invasive primary brain tumour, remains an incurable disease. Rho GTPases and their activators, guanine nucleotide exchange factors (GEFs), have central roles in GBM invasion. Anti-angiogenic therapies may stimulate GBM invasion via HGF/c-Met signalling. We aim to identify mediators of HGF-induced GBM invasion that may represent targets in a combination anti-angiogenic/anti-invasion therapeutic paradigm. METHODS: Guanine nucleotide exchange factor expression was measured by microarray analysis and western blotting. Specific depletion of proteins was accomplished using siRNA. Cell invasion was determined using matrigel and brain slice assays. Cell proliferation and survival were monitored using sulforhodamine B and colony formation assays. Guanine nucleotide exchange factor and GTPase activities were determined using specific affinity precipitation assays. RESULTS: We found that expression of Dock7, a GEF, is elevated in human GBM tissue in comparison with non-neoplastic brain. We showed that Dock7 mediates serum- and HGF-induced glioblastoma cell invasion. We also showed that Dock7 co-immunoprecipitates with c-Met and that this interaction is enhanced upon HGF stimulation in a manner that is dependent on the adaptor protein Gab1. Dock7 and Gab1 also co-immunoprecipitate in an HGF-dependent manner. Furthermore, Gab1 is required for HGF-induced Dock7 and Rac1 activation and glioblastoma cell invasion. CONCLUSIONS: Dock7 mediates HGF-induced GBM invasion. Targeting Dock7 in GBM may inhibit c-MET-mediated invasion in tumours treated with anti-angiogenic regimens.

Pacemaker activity in hydra is modulated by glycine receptor ligands.

In the mammalian central nervous system, the neurotransmitter, glycine, acts both on an inhibitory, strychnine-sensitive receptor (GlyR) and an excitatory, strychnine-insensitive site at the NMDA receptor. Here we present electrophysiological evidence that the strychnine-sensitive glycine agonists, glycine and taurine, and the antagonist, strychnine, affect the endodermal rhythmic potential (RP) system and that the ectodermal contraction burst (CB) pacemaker system is modulated by glycine and strychnine in hydra. The RP and CB pacemaker systems are responsible for the respective elongation and contraction of hydra's body column. Activity of the CB system, quantified by the rate of contraction bursts (CBs), the number of pulses per contraction burst (P/CB), and the duration of bursts, was decreased by glycine. Glycine, coadministered with the strychnine-insensitive glycine site blocker, indole-2-carboxylic acid (I2CA), decreased RPs but not CBs or P/CB. The effect was mimicked by taurine. Strychnine increased the duration of RP production, and decreased CB duration. The effect of glycine with I2CA was counteracted by strychnine. The results support the idea that a vertebrate-like GlyR may be involved in modulating activity of the endodermal RP system and suggest that a glycine site on an NMDA receptor may be involved in the CB system.

Cognitive impairment in patients suffering from relapsing-remitting multiple sclerosis with EDSS < or = 3.5.

OBJECTIVES: Previous papers have mainly demonstrated the presence and the frequency of cognitive impairment in patients suffering from relapsing-remitting multiple sclerosis. The purpose of this study was to investigate subjects with the relapsing-remitting form of the disease and mild clinical disability (EDSS < or = 3.5), so as to quantify this deficit when the illness does not yet interfere with daily living and the ability to work. METHODS: Fifty patients and 50 healthy controls were submitted to a wide neuropsychological battery, including Wechsler Memory Scale I- (WMS), Benton Visual Retention Test D- (BVRT), Raven Coloured Progressive Matrices (RCPM), Kohs' test (KT), Judgement of Lines Orientation H- (JLO), Facial Recognition (FR) and Aachner Aphasie Test (AAT). They also underwent Clinical Depression Scale (CDQ) and State-Trait Anxiety Inventory (STAI). RESULTS: The results show the presence of significant memory impairment on both WMS (P = 0.000) and BVRT (P = 0.000) in patients compared with controls. Patients were also impaired in abstract reasoning and problem-solving deficit (KT P = 0.003; RCPM P = 0.000) and in FR (P = 0.019). Cognitive decline correlated with illness duration (r = 0.761), but was independent of EDSS (r = 0.085). CONCLUSION: Cognitive decline was present even when physical disability was not yet severe, but it was mild and did not limit patients' ability to work. The cognitive impairment outlined was of the subcortical type and correlated with illness duration. This study emphasizes the importance of cognitive examination in clinical practice. It is suggested that a complete neurological examination include tests on memory and abstract reasoning.

Legal and assistance aspects of Alzheimer's disease: analysis of 100 cases.

Caring for patients with disabling cognitive diseases, such as Alzheimer's disease (AD) and other progressive dementias, has a number of legal and social welfare implications. The two main problems to be discussed with patients and caregivers are the need for a legal guardian and requests for government financial support, both of which depend on the patient's progressive loss of autonomy and increasing need for assistance. In order to study the presence of these two support measures, we considered 100 AD patients (56 women and 44 men) divided in four groups on the basis of the stage of the disease: mild (25), moderate (34) and severe (32), or death (9). We investigated the number of caregivers for each patient (and their relationship with the patient), the presence of a legal guardian, and whether government financial support had been obtained. The number of caregivers increased for each patient as the disease advanced (54% with moderate and 67% with severe disease had > or =1 caregiver), but only 11% of the patients had a guardian. The caregivers were most likely to be family members (70% were spouses, 45% offspring). Only 23% of the patients with moderate and 62% with severe disease received government financial support. Our data concerning the care of incompetent people (as AD patients progressively become) in juridical (guardianship/trusteeship/proxy/power of attorney) and social terms (government financial support) show that such aspects are not sufficiently taken into account until the patients reach a severe disease or have died.

Long-term interferon-beta treatment for multiple sclerosis.

The aim of our study was to analyze the dropout rate in patients with relapsing-remitting multiple sclerosis (RRMS) under long-term treatment with the three commercially available interferon beta (IFNbeta) preparations. According to the drug taken, we divided 122 RRMS patients into 4 groups: Betaferon group, 56 patients taking INFbeta-1b (24 MIU weekly, subcutaneous injections); Avonex group, 38 patients taking IFNbeta-1a (6 MIU weekly, intramuscularly); Rebif group, 18 patients taking INFbeta-1b (18 MIU subcutaneously). Ten patients who shifted from Betaferon to Avonex were included in a fourth group. Dropouts were registered every trimester with the related cause. Data were evaluated using Kaplan-Meier survival analysis and log-rank test. During the observation period of five years, 48 patients (39.9%) dropped out: 48% of the patients in Betaferon group withdrew at a median of 758 days, 26% of the Avonex group at 356 days; 38% of the Rebif group at 421 days, and 40% of those who shifted from Betaferon to Avonex at 259 days. The differences between groups were not significant on survival analysis. Patients receiving higher dose treatment (Betaferon and Rebif groups) dropped out mainly for clinical adverse events; conversely, patients receiving lower dose therapy (Avonex group) dropped out most often for inefficacy. Patients who shifted to a lower dose treatment (fourth group) had a dropout rate similar to that of the initial treatment. Our data showed that one-third of the patients stopped the therapy, mostly for adverse events and then for inefficacy, while the remaining two-thirds were still on treatment without problems up to 5 years of follow-up. Compliance seems related to the dose of the drug, but further analysis is needed to confirm our data.

Pancreatic encephalopathy: a 7-year follow-up case report and review of the literature.

Pancreatic encephalopathy is a rare complication of acute pancreatitis. Clinical features include focal neurological signs and acute onset of dementia. This picture can fluctuate over time: cyclic progression with remission and relapses has been described. We present the case of a 43-year-old man who, after an acute episode of pancreatitis, experienced five relapses, with alternating focal signs. The patient has improved, but cognitive impairment persists after a 7-year follow-up.

Clinical evaluation of thallium-201 single photon emission computed tomography in equivocal neuroradiological supratentorial lesions.

BACKGROUND: We performed cerebral 201Tl SPECT study on 38 presurgical patients with equivocal neuroradiological supratentorial lesions to detect differences in 201Tl uptake index between tumor/non-tumor and high-grade/low-grade samples. METHODS: Authors identified 38 cases with presurgical equivocal neuroradiological supratentorial mass lesions. All cases were submitted to histological confirmation of the lesion by biopsy, sub-total or gross-total removal of the tumor. Between 23 patients suffering from gliomas, 13 were histologically classified as being of low-grade malignant tumors and 10 were classified as being of high-grade malignancy. Fifteen non-tumor histopathological specimens were also detected. The 201Tl index was defined as the ratio of average counts per pixel in the lesion to these in the opposite region. Analysis of variance (ANOVA) and unpaired Student's OtO-test statistical methods were applied. Actuarial survival time from the date of diagnosis was calculated using the Kaplan-Meier method. Follow-up evaluation and survival time were obtained through referring physicians. Cerebral CT or MR images were obtained every three months after discharged, or more often if indicated. RESULTS: Results showed that the 201Tl uptake index ranged from 1.10 to 3.00 in the tumors lesions (mean+/-SD: 1.68+/-0.51) and from 0.80 to 1.40 in the non-tumors lesions (mean+/-SD: 1.07+/-0.17), (alpha < 0.0006 percent;). The 201Tl uptake index ranged from 1.10 to 2.30 in 13 patients with low-grade tumors (mean+/-SD: 1.45+/-0.34) and from 1.30 to 3.00 in 10 patients with high-grade tumors (mean+/-SD: 1.98+/-0.55), (alpha < 0.5 percent;). CONCLUSIONS: Our results demonstrate the clinical utility of 201Tl brain SPECT to differentiate equivocal neuroradiological supratentorial lesions and to correlate relationship between preoperative diagnosis, histological tumor grade and prognosis.

The small GTPase Rac suppresses apoptosis caused by serum deprivation in fibroblasts.

BACKGROUND: The small GTPase Rac1 is a key signaling protein that mediates a number of important physiologic functions including the organization of the actin cytoskeleton, lipid metabolism, and gene transcription. Rac1 has also been implicated in oncogenic transformation. Expression of constitutively active Rac1 in Rat1 fibroblasts elicits serum- and anchorage-independent growth and causes tumorigenicity in nude mice. The signaling pathways that mediate the role of Rac in cell transformation remain to be identified. Here, we study the role of Rac in cell survival in the absence of serum. MATERIALS AND METHODS: The cell lines used in this study are Ratl fibroblasts that express constitutively active or dominant negative mutants of Rac1. We used long-term video time-lapse microscopy to analyze the effects of these Rac1 mutants on mitogenicity and apoptosis. RESULTS: We show that the increase in viability, which is stimulated by Rac1 in the absence of serum, is predominantly caused by an inhibition of apoptosis, with a minor increase in cell division. We also show that Rac1-stimulated cell viability in serum-starved cells is inhibited by chemical inhibition of phosphatidylinositol 3-kinase. CONCLUSIONS: Our observations indicate a role for Rac1 in survival signaling, possibly via activation of phosphatidylinositol 3-kinase. We propose that Rac1-stimulated cell survival may contribute to the role of Rac1 in serum-independent growth and cell transformation.

Apolipoprotein E and intronic polymorphism of presenilin 1 and alpha-1-antichymotrypsin in Alzheimer's disease and vascular dementia.

Apolipoprotein E (ApoE) genotypes, presenilin 1 (PS-1) and alpha(1)-antichymotrypsin (ACT) polymorphism and the association of the genotypes were examined in patients with Alzheimer's disease (AD, n = 121) or vascular dementia (VD, n = 68) in comparison with elderly controls (n = 125). The frequency of the ApoE epsilon 4 allele was significantly increased both in late-onset AD (0.35) and in VD (0.17); the frequency of ApoE epsilon 2 was significantly reduced in AD, but it was similar in VD and controls. The presence of the allele 1 of PS-1 intronic polymorphism was not associated with AD or VD and was not influenced by the ApoE genotypes. Also, the frequency of allele A of the intronic polymorphism of ACT was similar in AD, VD and controls and it was not altered by ApoE or PS-1 genotypes. The results confirm the association between ApoE epsilon 4 and AD and indicate an increase in ApoE epsilon 4 in Vd, too. A potential protective role of ApoE epsilon 2 is also suggested for late-onset AD but not for VD. No association was shown between ACT allele A and PS-1 allele 1 in AD or VD.

Therapeutic considerations in cerebellopontine angle lipomas inducing hemifacial spasm.

Lipoma is a very rare tumour at the cerebellopontine angle. We report a case of incomplete hemifacial spasm, associated with a lipoma involving and compressing both facial and acoustic nerves at their origin in the brainstem. The patient was treated with medical therapy (botulinum toxin A) and surgery. We present a review of the last ten years of the literature, with particular regard to management.

Platelet-derived growth factor and fibronectin-stimulated migration are differentially regulated by the Rac and extracellular signal-regulated kinase pathways.

Directed cell migration is essential for a variety of important biological processes ranging from development and angiogenesis to metastasis. Ras plays a pivotal role in the signaling cascade that governs chemotaxis of fibroblasts toward platelet-derived growth factor-BB (PDGF-BB). Ras activates multiple downstream pathways, which include the extracellular signal-regulated kinase (ERK), Rac, and Ral signaling cascades. We therefore investigated the role of the Rac and ERK pathways in cell migration. We showed that migration of fibroblasts toward PDGF-BB is inhibited by expression of dominant negative Asn-17 Rac1. Blocking of the ERK pathway by either expression of dominant negative Ala-218/Ala-222-mitogen-activated protein kinase kinase (A218/A222-MEK1) or by a MEK-specific inhibitor did not inhibit migration toward PDGF-BB. In contrast, migration toward soluble fibronectin was suppressed by inhibition of the ERK pathway but not by Asn-17 Rac1 expression. These results indicate that directed cell migration mediated by different receptor classes in response to different ligands differentially utilizes the Rac and ERK pathways and suggest that Rac might play a critical role in pathological processes such as angiogenesis and metastasis.

Binding of 14-3-3 proteins to the protein kinase Raf and effects on its activation.

To identify proteins that may participate in the activation of the protein kinase Raf, proteins that interact with Raf were selected in a two-hybrid screen. Two members of the 14-3-3 protein family were isolated that interacted with both the amino terminal regulatory regions of Raf and the kinase domain of Raf, but did not compete with the guanine nucleotide-binding protein Ras for binding to Raf. 14-3-3 proteins associated with Raf in mammalian cells and accompanied Raf to the membrane in the presence of activated Ras. In yeast cells expressing Raf and MEK, mammalian 14-3-3 beta or 14-3-3 zeta activated Raf to a similar extent as did expression of Ras. Therefore, 14-3-3 proteins may participate in or be required for the regulation of Raf function. These findings suggest a role for 14-3-3 proteins in Raf-mediated signal transduction.

Raf-1 interferes with Ras and Rap1A effector functions in yeast.

Raf-1 is a serine/threonine kinase that acts downstream of Ras in mitogenic signal transduction pathways, but the mechanism by which Ras transmits signals to Raf-1 is not known. We have examined the interaction between Raf-1 and human H-ras in three different systems that utilize H-ras-induced phenotypes in Saccharomyces cerevisiae. In each system, the effects of H-ras depend on guanosine triphosphate and appear to be mediated through the H-ras effector binding region. H-ras effector function was blocked in each case by expression of the N-terminal regulatory domain of Raf-1. These inhibitory effects did not require the Raf-1 kinase domain. Raf-1 also blocked Rap1A effector function in S. cerevisiae. Raf-1, therefore, appears to interact with H-Ras and Rap1A in these in vivo systems with properties that suggest it is an immediate downstream effector.