Bortezomib-induced peripheral neurotoxicity: a neurophysiological and pathological study in the rat

Bortezomib is a new proteasome inhibitor with a high antitumor activity, but also with a potentially severe peripheral neurotoxicity. To establish a preclinical model and to characterize the changes induced on the peripheral nerves, dorsal root ganglia (DRG) and spinal cord, bortezomib was administered to Wistar rats (0.08, 0.15, 0.20, 0.30 mg/kg/day twice [2q7d] or three times [3q7d] weekly for a total of 4 weeks). At baseline, on days 14, 21 and 28 after the beginning the treatment period and during a 4-week follow-up period sensory nerve conduction velocity (SNCV) was determined in the tail of each animal. Sciatic nerve, DRG and spinal cord specimens were processed for light and electron microscope observations and morphometry. At the maximum tolerated dose bortezomib induced a significant reduction in SNCV, with a complete recovery at the end of the follow-up period. Sciatic nerve examination and morphometric determinations demonstrated mild to moderate pathological changes, involving predominantly the Schwann cells and myelin, although axonal degeneration was also observed. Bortezomib-induced changes were also observed in DRG and they were represented by satellite cell intracytoplasmatic vacuolization due to mitochondrial and endoplasmic reticulum damage, closely resembling the changes observed in sciatic nerve Schwann cells. Only rarely did the cytoplasm of DRG neurons has a dark appearance and clear vacuoles occurring in the cytoplasm. Spinal cord was morphologically normal. This model is relevant to the neuropathy induced by bortezomib in the treatment of human malignancies and it could be useful in increasing our knowledge regarding the mechanisms underlying bortezomib neurotoxicity.     

Multiple sclerosis and anti-Plasmodium falciparum innate immune response

Several epidemiological investigations conducted in Sardinia, insular Italy, indicate that the strong selective pressure of malaria along the centuries may have concurred to the elevated genetic MS-risk in this region. To test such hypothesis in an experimental setting, we have compared the immune response to P. falciparum (the causative agent of malaria) in Sardinian MS patients relative to their ethnic healthy controls and control MS patients of different ethnicity. To this purpose, the P. falciparum-driven peripheral mononuclear cell proliferation, the production of pro-inflammatory cytokines of the innate immunity such as TNF-alpha, IL-6 and IL-12 and the ability to inhibit the parasite growth have been tested in relation to HLA-DR alleles and TNF promoter polymorphisms known of being associated to MS. We found that P. falciparum-induced proliferation, cytokine production and parasite killing are significantly augmented in Sardinian MS patients as compared to controls (p<0.01). Additionally, a correlation is found with genes associated to Sardinian MS, namely the TNF(-376A) promoter polymorphism and the class II HLA-DRB1*0405 allele. In conclusion, we have found evidences that some genetic traits formerly selected to confer a protective responses to P. falciparum now partially contribute to the elevated MS susceptibility amongst Sardinians.     

Slow repetitive TMS for drug-resistant epilepsy: clinical and EEG findings of a placebo-controlled trial

PURPOSE: To assess the effectiveness of slow repetitive transcranial magnetic stimulation (rTMS) as an adjunctive treatment for drug-resistant epilepsy. METHODS: Forty-three patients with drug-resistant epilepsy from eight Italian Centers underwent a randomized, double-blind, sham-controlled, crossover study on the clinical and EEG effects of slow rTMS. The stimulus frequency was 0.3 Hz. One thousand stimuli per day were given at the resting motor threshold intensity for 5 consecutive days, with a round coil at the vertex. RESULTS: "Active" rTMS was no better than placebo for seizure reduction. However, it decreased interictal EEG epileptiform abnormalities significantly (p < 0.05) in one-third of the patients, which supports a detectable biologic effect. No correlation linked the rTMS effects on seizure frequency to syndrome or anatomic classification, seizure type, EEG changes, or resting motor threshold (an index of motor cortex excitability). CONCLUSIONS: Although the antiepileptic action was not significant (p > 0.05), the individual EEG reactivity to "active" rTMS may be encouraging for the development of more-powerful, noninvasive neuromodulatory strategies.     

Gender differences in bipolar disorder type 1: a 48-week prospective follow-up of 72 patients treated in an Italian tertiary care center

To explore gender differences in bipolar I disorder, we compared the longitudinal treatment outcome and baseline demographic and clinical characteristics of 27 male and 45 female adult subjects who were treated for an acute affective episode and longitudinally followed for a period of up to 48 weeks. Females were more likely to report a history of suicidal gestures and a comorbid panic disorder; males were more likely to present with a comorbid obsessive-compulsive disorder, and there was a trend for a more frequent history of alcohol or substance abuse. No significant differences were found between the genders for the time to remission from the index episode, number of recurrences, and time spent with any clinical or subclinical mood symptom during the 48 weeks of maintenance treatment. Although differences may exist between bipolar I male and female subjects, prospective course does not seem to reveal differences in a 48-week period, at least when similar treatment strategies are adopted.     

Impaired endothelial antithrombotic activity following short-term interruption of continuous subcutaneous insulin infusion in type 1 diabetic patients

Review of literature has shown an increased rate of thrombotic complications in diabetic patients with frequent episodes of hyperketonemia. However, the mechanisms by which ketosis promotes vascular disease in diabetic patients are unclear. It was the aim of this study to investigate early changes in haemostatic parameters and oxidative stress markers during the hyperketonemic status which follows the interruption of continuous subcutaneous insulin infusion (CSII) in type I diabetic patients. Eight CSII-treated type I diabetic patients underwent a 4-hour pump arrest. Blood glucose, insulin and 3-hydroxybutirate were measured to verify the metabolic response. A vein-occlusive (VO) test was performed for the determination of tPA and PAI-1 activities and their antigen levels before and after the CSII arrest. Coagulation factor VII and VIII were evaluated by one-stage PT and PTT method, respectively. TF, vWF, tPA and PAI-1 antigens were determined by ELISA, whereas tPA and PAI-1 activities using chromogenic methods. Plasma malondialdehyde (MDA) and protein carbonyl groups (PCG) levels were determined by HPLC and spectrophotometry, respectively. After the insulin deprivation phase, post-VO tPA antigen level significantly decreased (P = 0.0391), whereas TF and post-VO PAI-1 activity and antigen levels significantly increased (P = 0.0156 and P = 0.0234, respectively). Plasma MDA and PCG levels were 1.88-fold and 1.74-fold higher than baseline values, respectively. In conclusion, the impairment of the fibrinolytic potential and the increases in TF, MDA and PCG levels may enhance the risk of both arterial and venous thrombosis during ketosis. Thus, early detection of hyperketonemia in DM patients could contribute to the prevention of life-threatening vascular events.     

Cleavage of cystatin C is not associated with multiple sclerosis

Recently, Irani and colleagues proposed a C-terminal cleaved isoform cystatin C (12.5 kDa) in cerebrospinal fluid as a marker of multiple sclerosis. In this study, we demonstrate that the 12.5 kDa product of cystatin C is formed by degradation of the first eight N-terminal residues. Moreover, such a degradation is not specific in the cerebrospinal fluid of multiple sclerosis, but rather is given by an inappropriate sample storage at -20 degrees C. We conclude that the use of the 12.5 kDa product of cystatin C in cerebrospinal fluid might lead to a fallacious diagnosis of multiple sclerosis. Preanalytical validation procedure is mandatory for proteomics investigations.     

Hormonal replacement therapy in women with Parkinson disease and levodopa-induced dyskinesia: a crossover trial

Eleven postmenopausal women with Parkinson disease and levodopa-induced peak-dose dyskinesias underwent a double-blind, placebo-controlled, crossover study. The active treatment consisted of estrogen replacement therapy for 12 weeks, followed by medroxyprogesterone acetate for 2 weeks. Estrogen replacement therapy-medroxyprogesterone acetate administration significantly improved peak-dose dyskinesia without worsening motor disability, thus suggesting a possible benefit on dyskinesias in postmenopausal women with Parkinson disease.     

Craniodigital syndrome of Scott: clinical and neuroradiological features of a new case

We report on a girl presenting with mental retardation, craniofacial dysmorphisms, and syndactyly. The child's mother and maternal grandfather presented bilateral syndactyly of toes 2 and 3. These manifestations, falling within the ambit of what has been termed the craniodigital syndromes, were first reported by Scott et al (1971) in 3 brothers.     

Unawareness of motor impairment and emotions in right hemispheric stroke: a preliminary investigation

BACKGROUND: Awareness may lack in some stroke patients who are not capable of evaluating the nature and severity of illness. Thus, unawareness may have different forms such as anosognosia, neglect, and alexithymia or unawareness of emotions. In this study we investigated the relationship among anosognosia, neglect, alexithymia, and cognition. METHODS: Fifty consecutive right stroke inpatients were approached within the first 3 months from the acute event. Anosognosia was measured with the Bisiach scale, alexithymia with the TAS-20 scale and neglect with line crossing, letter cancellation, figure and shape copying, and line bisection tests. A neuropsychological test battery was used to measure different areas of cognition. RESULTS: despite the strong comorbidity rate among the different forms of unawareness, there are patients who suffer from pure forms of these types of lack of awareness. A multivariate logistic regression model evidenced that presence of neglect (OR = 10.3; 95% CI = 1.4-76.3; p = 0.023) and more difficulty in describing feelings (TAS-20 F2 subscore; OR = 1.3; 95% CI = 1.1-1.7; p = 0.014) were the only predictors of anosognosia. In addition, anosognosics with alexithymia performed worst in a frontal task such as the verbal fluency task (p = 0.042) and in the verbal span forward task (p = 0.026) than pure anosognosics. CONCLUSIONS: Anosognosia for motor impairment is strictly associated with a specific form of unawareness of emotions. Future studies have to clarify if frontal cognitive impairment previously described in anosognosics is a manifestation of unawareness of emotions or anosognosia for motor impairment.     

Pentylenetetrazol kindling alters adenine and guanine nucleotide catabolism in rat hippocampal slices and cerebrospinal fluid

Pentylenetetrazol (PTZ) is commonly used as a convulsant drug. The enhanced seizure susceptibility induced by kindling is probably attributable to plastic changes in the synaptic efficacy. Adenosine and guanosine act both as important neuromodulators and neuroprotectors with mostly inhibitory effects on neuronal activity. Adenosine and guanosine can be released per se or generated from released nucleotides (ATP, ADP, AMP, GTP, GDP, and GMP) that are metabolized and rapidly converted to adenosine and guanosine. The aim of this study was to evaluate nucleotide hydrolysis by ecto- and soluble nucleotidases (hippocampal slices and CSF, respectively) after PTZ-kindling (stages 3, 4, or 5 seizures) or saline treatment in rats. Additionally, the levels of purines in rat cerebrospinal fluid (CSF), as well as ecto-NTPDases (1, 2, 3, 5, 6 and 8) and ecto- 5'-nucleotidase expression were determined. Ecto-enzyme assays demonstrated that ATP, AMP, GDP, and GMP hydrolysis enhanced when compared with controls. In addition, there was an increase of ADP, GDP, and GMP hydrolysis by soluble nucleotidases in PTZ-kindling rats compared to control group. The HPLC analysis showed a marked increase in PTZ-kindled CSF concentrations of GTP, ADP, and uric acid, but GDP, AMP, and hypoxanthine concentrations were decreased. Such alterations indicate that the modulatory role of purines in CNS could be affected by PTZ-kindling. However, the physiological significance of these findings remains to be elucidated.