Direct Comparison between Förster Resonance Energy Transfer and Light-Induced Triplet-Triplet Electron Resonance Spectroscopy.

To carry out reliable and comprehensive structural investigations, the exploitation of different complementary techniques is required. Here, we report that dual triplet-spin/fluorescent labels enable the first parallel distance measurements by electron spin resonance (ESR) and Förster resonance energy transfer (FRET) on exactly the same molecules with orthogonal chromophores, allowing for direct comparison. An improved light-induced triplet-triplet electron resonance method with 2-color excitation is used, improving the signal-to-noise ratio of the data and yielding a distance distribution that provides greater insight than the single distance resulting from FRET.

Peptaibol Analogs Show Potent Antibacterial Activity against Multidrug Resistant Opportunistic Pathogens.

New classes of antibacterial drugs are urgently needed to address the global issue of antibiotic resistance. In this context, peptaibols are promising membrane-active peptides since they are not involved in innate immunity and their antimicrobial activity does not involve specific cellular targets, therefore reducing the chance of bacterial resistance development. Trichogin GA IV is a nonhemolytic, natural, short-length peptaibol active against Gram-positive bacteria and resistant to proteolysis. In this work, we report on the antibacterial activity of cationic trichogin analogs. Several peptides appear non-hemolytic and strongly active against many clinically relevant bacterial species, including antibiotic-resistant clinical isolates, such as Staphylococcus aureus, Acinetobacter baumannii, and extensively drug-resistant Pseudomonas aeruginosa, against which there are only a limited number of antibiotics under development. Our results further highlight how the modification of natural peptides is a valuable strategy for obtaining improved antibacterial agents with potential therapeutic applications.

Anticancer and Targeting Activity of Phytopharmaceutical Structural Analogs of a Natural Peptide from Trichoderma longibrachiatum and Related Peptide-Decorated Gold Nanoparticles.

In the large field of bioactive peptides, peptaibols represent a unique class of compounds. They are membrane-active peptides, produced by fungi of the genus Trichoderma and known to elicit plant defenses. Among the short-length peptaibols, trichogin GA IV is nonhemolytic, proteolysis-resistant, antibacterial, and cytotoxic. Several trichogin analogs are endowed with potent activity against phytopathogens, thus representing a sustainable alternative to copper for plant protection. In this work, we tested the activity of trichogin analogs against a breast cancer cell line and a normal cell line of the same derivation. Lys-containing trichogins showed an IC50 below 12 µM, a peptide concentration not significantly affecting the viability of normal cells. Two analogs were found to be membrane-active but noncytotoxic. They were anchored to gold nanoparticles (GNPs) and further investigated for their ability to act as targeting agents. GNP uptake by cancer cells increased with peptide decoration, while it decreased in the corresponding normal epithelial cells. This work highlights the promising biological properties of peptaibol analogs in the field of cancer therapy either as cytotoxic molecules or as active targeting agents in drug delivery.

Synthesis, Conformational Analysis and Antitumor Activity of the Naturally Occurring Antimicrobial Medium-Length Peptaibol Pentadecaibin and Spin-Labeled Analogs Thereof.

Peptaibols are proteolysis-resistant, membrane-active peptides. Their remarkably stable helical 3D-structures are key for their bioactivity. They can insert themselves into the lipid bilayer as barrel staves, or lay on its surface like carpets, depending on both their length and the thickness of the lipid bilayer. Medium-length peptaibols are of particular interest for studying the peptide-membrane interaction because their length allows them to adopt either orientation as a function of the membrane thickness, which, in turn, might even result in an enhanced selectivity. Electron paramagnetic resonance (EPR) is the election technique used to this aim, but it requires the synthesis of spin-labeled medium-length peptaibols, which, in turn, is hampered by the poor reactivity of the Cα-tetrasubstituted residues featured in their sequences. After several years of trial and error, we are now able to give state-of-the-art advice for a successful synthesis of nitroxide-containing peptaibols, avoiding deleted sequences, side reactions and difficult purification steps. Herein, we describe our strategy and itsapplication to the synthesis of spin-labeled analogs of the recently discovered, natural, medium-length peptaibol pentadecaibin. We studied the antitumor activity of pentadecaibin and its analogs, finding potent cytotoxicity against human triple-negative breast cancer and ovarian cancer. Finally, our analysis of the peptide conformational preferences and membrane interaction proved that pentadecaibinspin-labeling does not alter the biological features of the native sequence and is suitable for further EPR studies. The nitroxide-containing pentadecaibins, and their synthetic strategy described herein, will help to shed light on the mechanism of the peptide-membrane interaction of medium-length peptaibols.

Correspondence between neurophysiological and clinical measurements of chemotherapy-induced peripheral neuropathy: secondary analysis of data from the CI-PeriNomS study.

Chemotherapy-induced peripheral neuropathy (CIPN) lacks standardized clinical measurement. The objective of the current secondary analysis was to examine data from the CIPN Outcomes Standardization (CI-PeriNomS) study for associations between clinical examinations and neurophysiological abnormalities. Logistic regression estimated the strength of associations of vibration, pin, and monofilament examinations with lower limb sensory and motor amplitudes. Examinations were classified as normal (0), moderately abnormal (1), or severely abnormal (2). Among 218 participants, those with class 1 upper extremity (UE) and classes 1 or 2 lower extremity (LE) monofilament abnormality were 2.79 (95% confidence interval [CI]: 1.28-6.07), 3.49 (95%CI: 1.61-7.55), and 4.42 (95%CI: 1.35-14.46) times more likely to have abnormal sural nerve amplitudes, respectively, compared to individuals with normal examinations. Likewise, those with class 2 UE and classes 1 or 2 LE vibration abnormality were 8.65 (95%CI: 1.81-41.42), 2.54 (95%CI: 1.19-5.41), and 7.47 (95%CI: 2.49-22.40) times more likely to have abnormal sural nerve amplitudes, respectively, compared to participants with normal examinations. Abnormalities in vibration and monofilament examinations are associated with abnormal sural nerve amplitudes and are useful in identifying CIPN.

The Therapeutic Effect of Botulinum Toxin Type A on Trigeminal Neuralgia: Are There Any Differences between Type 1 versus Type 2 Trigeminal Neuralgia?

BACKGROUND: Botulinum toxin type A is an effective treatment for trigeminal neuralgia. Moreover, its efficacy in type 2 trigeminal neuralgia and comparative studies between type 1 and type 2 trigeminal neuralgia (TN) still need to be improved. METHODS: We treated 40 TN patients with onabotulinumtoxinA; 18 had type 1 TN, and 22 had type 2 TN. We compared the baseline pain score with the Visual Analogue Scale (VAS) and paroxysm frequency (number per week) at the baseline with those obtained at 1-month and 3-month follow-ups. Nonetheless, we compared the baseline Penn Facial Pain Scale with the scores obtained at the 1-month follow-up. RESULTS: BoNT/A effectively reduced pain intensity and frequency at the 1-month and 3-month follow-ups. Moreover, the type 1 TN and type 2 TN groups had baseline pain scores of 7.8 ± 1.65 and 8.4 ± 1.1, respectively. Pain significantly improved (p < 0.001) in both groups to 3.1 ± 2.3 (type 1 TN) and 3.5 ± 2.3 (type 2 TN) at the 1-month follow-up and to 3.2 ± 2.5 (type 1 TN) and 3.6 ± 2.5 (type 2 TN) at the 3-month follow-up. There was no difference between the two groups (p 0.345). The baseline paroxysm frequencies (number per week) were 86.7 ± 69.3 and 88.9 ± 62.2 for the type 1 and type 2 TN groups, respectively; they were significantly reduced in both groups at the 1-month and 3-month follow-ups without significant differences between the two groups (p 0.902). The Pain Facial Pain Scale improved at the 1-month follow-up, and no significant differences were found between the two groups. There was a strong correlation between background pain and paroxysm pain intensity (r 0.8, p < 0.001). CONCLUSIONS: Botulinum toxin type A effectively reduced the pain, paroxysm frequency, and PFPS scores of type 1 and type 2 trigeminal neuralgia patients without statistically significant differences. Facial asymmetry was the only adverse event.

Pachymeningeal involvement in POEMS syndrome: MRI and histopathological study.

Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes (POEMS) syndrome is a rare plasma cell disease. Vascular endothelial growth factor (VEGF) seems to play a pathogenic role. Peripheral neuropathy is the main neurological feature. Cranial pachymeningitis has occasionally been reported, but no histopathological studies have been performed. The authors extensively evaluated the central nervous system MRI in 11 patients (seven men, four women; mean age at diagnosis 54.45 years) with POEMS syndrome. In two patients, meningeal histopathology with staining for VEGF and VEGF receptor was performed, and pachymeningeal involvement characterised at histopathological, immunohistochemical and confocal microscopy levels. Nine patients presented with cranial pachymeningitis. One patient suffered from migraine, and none complained of cranial nerve palsies or visual loss. None showed any MRI signs of spinal pachymeningitis. No correlation was found with disease duration and VEGF serum level. Histopathology showed hyperplasia of meningothelial cells, neovascularisation and obstructive vessel remodelling, without inflammation. VEGF and VEGF receptor were strongly coexpressed on endothelium, smooth-muscle cells of arterioles and meningothelial cells. In conclusion, POEMS patients present a high prevalence of meningeal involvement. The histological changes, different from those present in chronic pachymeningitis of other aetiology, suggest a possible VEGF role in the pathogenesis of the meningeal remodelling.

Reversible isolated sensory axonal neuropathy due to cobalamin deficiency.

Vitamin B(12) deficiency causes a wide range of hematological, gastrointestinal, and neurological manifestations. The most common neurological complication is subacute combined degeneration, sometimes associated with polyneuropathy. Isolated peripheral neuropathy due to cyanocobalamin deficiency is less frequent, and thus it may be overlooked. We describe 2 patients with isolated sensory axonal neuropathy secondary to vitamin B(12) deficiency who had complete clinical and electrophysiological recovery after cyanocobalamin replacement. Testing for serum vitamin B(12) and its metabolites should be done in any distal symmetric neuropathy.

Subcutaneous BoNT/A Injection for Intractable Pain and Disability in Complex Regional Pain Syndrome: A Case Report.

We treated a 51-year-old woman with refractory Complex Regional Pain Syndrome type I (CRPS-I) involving her left hand and forearm with subcutaneous injections of BoNT/A. The injections were performed every 3 months, with a total of six treatments. Each treatment was able to effectively improve pain and motor impairment; however, the duration of the effect was limited to only a few months. BoNT/A could improve patients' quality of life with CRPS; however, extensive clinical studies are needed to determine its role in clinical practice.

A Case Report of Pulsed Radiofrequency Plus Suboccipital Injection of the Greater Occipital Nerve: An Easier Target for Treatment of Cluster Headache.

Introduction: In cluster headache, the efficacy of suboccipital steroid injection is notable within a few days, although few data are available about the duration of efficacy. A combination treatment, consisting of suboccipital steroid injection plus pulsed radiofrequency, could potentially lead to long-term benefit. Evidence about pulsed radiofrequency of the greater occipital nerve is lacking. Patients and Methods: We retrospectively describe a series of four cluster headache patients treated with suboccipital steroid injection plus pulsed radiofrequency of the greater occipital nerve. Results: All patients achieved a 50% reduction in attack frequency in the 7 days after the first treatment. Moreover, a long pain-free remission period up to 15 months was noted. Conclusion: Suboccipital steroid injection plus pulsed radiofrequency of the greater occipital nerve might have both acute and prophylactic effects in cluster headache. The greater occipital nerve is more accessible to pulsed radiofrequency than other targets.

Lenalidomide long-term neurotoxicity: Clinical and neurophysiologic prospective study.

OBJECTIVE: To evaluate long-term lenalidomide neurotoxicity and correlation with cumulative dose and hematologic response. METHODS: Nineteen myeloma patients (7 men, mean age 63.2 years) underwent clinical and neurophysiologic assessment at baseline and at 2 (8 patients, group A) or 5 years (11 patients, group B) after starting lenalidomide therapy for relapsed/refractory multiple myeloma. Neuropathy was scored with Total Neuropathy Score clinical version (TNSc). Lenalidomide cumulative dose was correlated with severity of neuropathy and hematologic response. RESULTS: At enrollment, 7/19 patients (3 in group A, 4 in group B) had neurophysiologic signs of neuropathy secondary to previous chemotherapy, in 2 of them subclinical. Neurophysiologic evidence of sensory axonal neuropathy occurred in 4/8 patients at 2 years follow-up (group A) and in 3/11 patients at 5 years follow-up (group B). Dorsal sural nerve sensory action potential amplitude was the earliest neurophysiologic abnormality. No relevant (≥4) clinical changes were found in TNSc score. Hematologic overall response was 62% in group A and 100% in group B. No correlation was found between lenalidomide cumulative dose and neuropathy or between neuropathy and hematologic response. CONCLUSIONS: In our study, up to 50% of myeloma patients on long-term lenalidomide therapy developed sensory axonal neuropathy. Reduced dorsal sural nerve sensory action potential amplitude was the first neurophysiologic alteration. Neuropathy was usually subclinical or mild, however. Neurotoxicity was independent of lenalidomide cumulative dose and hematologic response.

Polyneuropathy with anti-sulfatide and anti-MAG antibodies: clinical, neurophysiological, pathological features and response to treatment.

IgM paraproteins often present reactivity to myelin-associated glycoprotein (MAG) and sulfatide. We describe the clinical and neurophysiological findings, and therapy response in 21 patients with IgM paraproteinemic neuropathy (15 with anti-MAG antibodies, 1 with anti-sulfatide antibodies, and 5 with both reactivity), and in 2 with anti-sulfatide positivity and no hematological disease. All patients complained of sensory symptoms, the majority had demyelinating neuropathy. Indirect immunofluorescence on human normal sural nerves disclosed different staining patterns. Eight of 13 patients (6 anti-MAG, 1 anti-sulfatide, 1 both anti-sulfatide and anti-MAG antibodies) improved after Rituximab. IVIg, steroids and plasma-exchange were also administered with different responses.

Pentraxin-3 and VEGF in POEMS syndrome: a 2-year longitudinal study.

Circulating Pentraxin 3 (PTX3) and vascular endothelial growth factor (VEGF) levels were measured longitudinally (mean follow-up 2 years) by ELISA in 6 patients with polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes (POEMS) syndrome and 16 controls. Expression of PTX3 was also assessed (immunohistochemistry) on sural nerve biopsies from POEMS and vasculitic neuropathy patients. No correlation was found between PTX3 and VEGF levels in POEMS or controls. Sural nerve biopsies from vasculitic neuropathy patients, but not those from POEMS syndrome, showed strong PTX3 staining. PTX3, expression of vessel inflammation/remodeling, and VEGF, crucial pro-angiogenic cytokine, appear to be independently regulated in POEMS syndrome.

Cobalamin deficiency: clinical picture and radiological findings.

Vitamin B12 deficiency causes a wide range of hematological, gastrointestinal, psychiatric and neurological disorders. Hematological presentation of cobalamin deficiency ranges from the incidental increase of mean corpuscular volume and neutrophil hypersegmentation to symptoms due to severe anemia, such as angor, dyspnea on exertion, fatigue or symptoms related to congestive heart failure, such as ankle edema, orthopnea and nocturia. Neuropsychiatric symptoms may precede hematologic signs and are represented by myelopathy, neuropathy, dementia and, less often, optic nerve atrophy. The spinal cord manifestation, subacute combined degeneration (SCD), is characterized by symmetric dysesthesia, disturbance of position sense and spastic paraparesis or tetraparesis. The most consistent MRI finding is a symmetrical abnormally increased T2 signal intensity confined to posterior or posterior and lateral columns in the cervical and thoracic spinal cord. Isolated peripheral neuropathy is less frequent, but likely overlooked. Vitamin B12 deficiency has been correlated negatively with cognitive functioning in healthy elderly subjects. Symptoms include slow mentation, memory impairment, attention deficits and dementia. Optic neuropathy occurs occasionally in adult patient. It is characterized by symmetric, painless and progressive visual loss. Parenteral replacement therapy should be started soon after the vitamin deficiency has been established.

NK cells and their receptors in naive and rituximab-treated patients with anti-MAG polyneuropathy.

BACKGROUND: Natural killer (NK) cells can bridge innate and acquired immunity, and play a role in autoimmunity. A few studies evaluated the distribution of NK cells and the expression of their receptors in chronic immune-mediated demyelinating polyneuropathies. We investigated NK cell distribution and NK cell receptor expression in 20 naïve patients with anti-MAG polyneuropathy (MAG-PN). METHODS: Using flow cytometry, we analysed NK cells and a series of NK cell receptors in the peripheral blood of patients with MAG-PN, and, as controls, in patients with chronic inflammatory demyelinating peripheral polyradiculoneuropathy (CIDP) and in healthy subjects. Six MAG-PN patients were also tested after rituximab treatment. RESULTS: At baseline the percentage of NK cells did not differ among the groups. KIR2DL2 receptor expression in MAG-PN patients was higher, andCD94/NKG2A receptor expression in both MAG-PN and CIDP patients was lower than in healthy controls. These abnormalities did not correlate with any clinical or demographic variable. No modification was found after rituximab therapy. CONCLUSIONS: The data suggest that MAG-PN shows abnormalities in NK cell receptors that characterise other autoimmune diseases, and cannot help in differential diagnosis with CIDP. The impairment of the relevant CD94/NKG2A inhibitory pathway, which might play a central role in the development and perpetuation of MAG-PN, warrants further functional investigations.