Engineering a platform for nerve regeneration with direct application to nerve repair technology.

The development of effective treatment options for repair of peripheral nerves is complicated by lack of knowledge concerning the interactions between cells and implants. A promising device, the multichannel scaffold, incorporates microporous channels, aligning glia and directing axonal growth across a nerve gap. To enhance clinical outcomes of nerve repair, a platform, representative of current implant technology, was engineered which 1) recapitulated key device features (porosity and linearity) and 2) demonstrated remyelination of adult neurons. The in vitro platform began with the study of Schwann cells on porous polycaprolactone (PCL) and poly(lactide co-glycolide) (PLGA) substrates. Surface roughness determined glial cell attachment, and an additional layer of topography, 40 µm linear features, aligned Schwann cells and axons. In addition, direct co-culture of sensory neurons with Schwann cells significantly increased neurite outgrowth, compared to neurons cultured alone (naive or pre-conditioned). In contrast to the control substrate (glass), on porous PCL substrates, Schwann cells differentiated into a mature myelinating phenotype, expressing Oct-6, MPZ and MBP. The direct applicability of this platform to nerve implants, including its response to physiological cues, allows for optimization of cell-material interactions, close observation of the regeneration process, and the study of therapeutics, necessary to advance peripheral nerve repair technology.

Taxane-containing induction chemotherapy followed by definitive chemoradiotherapy. Outcome in patients with locally advanced head and neck cancer.

BACKGROUND: Induction chemotherapy followed by definitive chemoradiotherapy is an intensified treatment approach for locally advanced squamous cell carcinoma of the head and neck (HNSCC) that might be associated with high rates of toxicity. MATERIALS AND METHODS: The data of 40 consecutive patients who underwent induction chemotherapy with docetaxel-containing regimens followed by intensity-modulated radiotherapy (IMRT) and concomitant systemic therapy for unresectable locally advanced HNSCC were retrospectively analyzed. Primary objectives were RT-related acute and late toxicity. Secondary objectives were response to induction chemotherapy, locoregional recurrence-free survival (LRRFS), overall survival (OS), and influencing factors for LRRFS and OS. RESULTS: The median follow-up for surviving patients was 21 months (range, 2-53 months). Patients received a median of three cycles of induction chemotherapy followed by IMRT to 72 Gy. Three patients died during induction chemotherapy and one during chemoradiotherapy. Acute RT-related toxicity was of grade 3 and 4 in 72 and 3 % of patients, respectively, mainly dysphagia and dermatitis. Late RT-related toxicity was mainly xerostomia and bone/cartilage necrosis and was of grade 3 and 4 in 15 % of patients. One- and 2-year LRRFS and OS were 72 and 49 % and 77 and 71 %, respectively. CONCLUSION: Induction chemotherapy followed by chemoradiotherapy using IMRT was associated with a high rate of severe acute and late RT-related toxicities in this selected patient cohort. Four patients were lost because of fatal complications. Induction chemotherapy did not compromise the delivery of full-dose RT; however, the use of three cycles of concomitant cisplatin was impaired.

Major bleeding of the upper aerodigestive tract due to oral anticoagulant/antibiotic interactions.

INTRODUCTION: Although a well-known complication in certain medical specialties, major bleeding due to the interaction between oral anticoagulants and antibiotics has been rarely reported concerning the upper aerodigestive tract. We report three cases of life-threatening bleeding of the upper aerodigestive tract in a context of antibiotic therapy in patients treated with oral anticoagulants. CASE SERIES: Three male patients under coumadin anticoagulation therapy presented major bleeding in three different contexts (epistaxis, peritonsillar abscess and postoperative course after total laryngectomy). Surgical intervention for hemostasis was required in all cases, with coagulation correction in two. Complications were severe anemia (2/3) and chronic heart failure (1/3). DISCUSSION/CONCLUSIONS: Interactions between two drugs commonly used in otolaryngology can result in major bleeding. The goal of this article is to raise practitioners' awareness of a potentially fatal, although rare, complication. We also review the main preventive strategies.

Neuronal expression of Fig4 is both necessary and sufficient to prevent spongiform neurodegeneration.

FIG4 is a ubiquitously expressed phosphatase that, in complex with FAB1/PIKFYVE and VAC14, regulates the biosynthesis of the signaling lipid PI(3,5)P(2). Null mutation of Fig4 in the mouse results in spongiform degeneration of brain and peripheral ganglia, defective myelination and juvenile lethality. Partial loss-of-function of human FIG4 results in a severe form of Charcot-Marie-Tooth neuropathy. Neurons from null mice contain enlarged vacuoles derived from the endosome/lysosome pathway, and astrocytes accumulate proteins involved in autophagy. Other cellular defects include astrogliosis and microgliosis. To distinguish the contributions of neurons and glia to spongiform degeneration in the Fig4 null mouse, we expressed Fig4 under the control of the neuron-specific enolase promoter and the astrocyte-specific glial fibrillary acidic protein promoter in transgenic mice. Neuronal expression of Fig4 was sufficient to rescue cellular and neurological phenotypes including spongiform degeneration, gliosis and juvenile lethality. In contrast, expression of Fig4 in astrocytes prevented accumulation of autophagy markers and microgliosis but did not prevent spongiform degeneration or lethality. To confirm the neuronal origin of spongiform degeneration, we generated a floxed allele of Fig4 and crossed it with mice expressing the Cre recombinase from the neuron-specific synapsin promoter. Mice with conditional inactivation of Fig4 in neurons developed spongiform degeneration and the full spectrum of neurological abnormalities. The data demonstrate that expression of Fig4 in neurons is necessary and sufficient to prevent spongiform degeneration. Therapy for patients with FIG4 deficiency will therefore require correction of the deficiency in neurons.

[Radiation-induced xerostomia: prevention, treatment, perspectives]. / Xérostomie radio-induite: prevéntion, traitement, perspectives.

Most of head and neck cancer patients will undergo radiotherapy. Xerostomia is probably its most frequent side effect. Subjective and objective criteria allow evaluating and grading xerostomia. New radiotherapy techniques and use of cytoprotectants can help to preserve salivary gland function. Parasym-pathicomimetics and saliva substitutes reduce symptoms. Strict mouth cleaning and fluoride's use prevent teeth deterioration and infections. Important breakthroughs have been made in the pathophysiology of xerostomia and new treatments are developed.

[Uncommon position of a retropharyngeal impacted fishbone]. / Ungewöhnliche Lage einer retropharyngeal eingespiessten Fischgräte.

The case of a 34-year-old otherwise healthy woman with retropharyngeal abscess due to a fishbone injury and presenting with neck stiffness and aphagia without visualization of a pharyngeal mucosal lesion is reported. The case illustrates that sore throat with symptoms out of proportion to oropharyngeal findings should prompt a search for pathologies other than simple pharyngotonsillitis. Other typical symptoms of a retropharyngeal abscess are high fever, dysphagia, hot potato voice and, less commonly, dyspnea and sepsis. Retropharyngeal abscess in adults occurs most often as a complication of a spread of infection from a pharyngeal focus, a foreign body injury, an iatrogenic trauma due to tracheal intubation or endoscopy, and blunt or perforating neck trauma. Contrary to children, a retropharyngeal abscess in adults without loco-regional infection or preceding trauma is very rare. This case illustrates how important imaging investigations (CT-scan) are in order to locate foreign bodies and to decide on surgical management. Aetiology, presenting signs, symptoms, methods of diagnosis, treatment and complications of a retropharyngeal abscess are briefly discussed.

Impaired CD8+ T-cell reactivity against viral antigens in cancer patients with solid tumors.

BACKGROUND: Patients with hematological malignancies are at increased risk for various infections. In patients with solid cancer, a variety of immunosuppressive mechanisms affecting T-cell response are described. We hypothesized that patients with advanced solid tumors may exhibit an impaired recognition of viral antigens. To test this, the capability of CD8+ T cells to recognize recall antigens from influenza and vaccinia virus was compared in patients and healthy individuals. Since all patients and most of the healthy individuals had been vaccinated against vaccinia years ago, comparison of the two groups was expected to be especially informative with respect to distinct effector T-cell reactivity. MATERIALS AND METHODS: Our test population included 16 healthy individuals and 12 patients with advanced solid cancers who were currently not receiving chemotherapy. We stimulated peripheral blood mononuclear cells (PBMC) ex vivo with the well-characterized influenza A matrix 58-66 peptide and the immunogenic and HLA-A*0201 restricted peptide epitope SLSAYIIRV derived from the modified vaccinia virus Ankara (MVA). A specific CD8+ T-cell reactivity was determined by quantitative real-time polymerase chain reaction (qRT-PCR) measuring changes in interferon gamma (IFN-gamma) mRNA expression levels. RESULTS: We found that significantly fewer cancer patients than healthy individuals exhibited specific T-cell recognition of the vaccinia epitope (25% and 69%, respectively). In addition, strength of the T-cell responses against both viral peptides was significantly reduced in cancer patients. CONCLUSION: Patients with advanced tumors are Less likely to mount a T-cell response against viral epitopes. These findings may have implications for the design of immunotherapeutic interventions against virus-induced diseases, including tumors.

Ratings of overall olfactory function.

The aim of this study was to investigate the accuracy of self-reported ratings of olfactory function in 83 healthy subjects. Such ratings were compared with quantitative measures of olfactory function, as well as with ratings of nasal patency. In experiment 1 subjects rated olfactory function and nasal patency before olfactory testing, whereas in experiment 2 the reverse was the case. No feedback regarding test results were provided until after completion of the testing. The principal findings were: (i) when ratings preceded measurements of olfactory function, there was no significant correlation between the two parameters. However, ratings of olfactory function correlated significantly with ratings of nasal airway patency. (ii) In contrast, when measurements of olfactory function preceded the ratings, this constellation switched. Now ratings of olfactory function correlated significantly with measured olfactory function, whereas there was no significant correlation between ratings of nasal airway patency and ratings of olfactory function. In conclusion, these data suggest that ratings of olfactory function are unreliable in healthy, untrained subjects. The ratings seem to reflect changes of nasal airway patency to a larger degree than measurable olfactory function. The results further indicate that this is mainly due to the limited attention the sense of smell receives in daily life.

Comparison of once- versus twice-daily use of beclomethasone dipropionate aqueous nasal spray in the treatment of allergic and non-allergic chronic rhinosinusitis.

The aim of the study was to assess the efficacy and safety of nasal aqueous beclomethasone dipropionate (BDP), 400 micro g/day, given via a metered pump in a once-daily or twice-daily regimen following a double-blind, parallel group design over a 12-week period. Adult patients (n=112) with allergic or non-allergic chronic rhinosinusitis recorded their nasal and ocular symptoms for the 7-day run-in period and for the first 4 weeks of treatment. At baseline and after 4 weeks the airways' resistance via active anterior rhinomanometry and the volume and area section via acoustic rhinometry were measured. Morning serum cortisol was measured at baseline and at week 12. Adverse events were to be reported at each visit. Of the 112 randomised patients, three did not enter the ITT analysis and another 13 in total discontinued the treatment. Significant improvements over the baseline were reported in both groups for the primary variable sum of nasal scores (-53.7% in the once-daily group and -59.7 in the twice-daily group), as well as for each nasal and ocular symptoms, without differences between the groups. Because of a wider variability than expected, the 95% confidence interval (C.I.) for the difference between the least square means exceeded the pre-defined limit of +/-10% of the reference mean. Similar improvements in both groups were also reported for the nasal airway patency's parameters. The total number of drug-related adverse events was 26 in the once-daily group and 32 in the twice-daily group, with most of the events consisting of local effects at the site of application. No signs of adrenal suppression were observed, and serum morning cortisol values did not significantly change. The once-daily BDP dosing (400 micro g/day) therefore has a similar efficacy and safety profile as the same daily dose given in a twice-daily regimen.

Somato-sympathetic vasoconstriction to intranasal fluid administration with consecutive decrease in nasal nitric oxide.

AIM: Patients suffering from non-allergic chronic rhinosinusitis (NACRS) increasingly use intranasal saline sprays. They report better nasal comfort. METHODS: In order to better understand this phenomenon, we studied intranasal laser Doppler flowmetry (LDF) and nasal nitric oxide (NO) variations evoked by local administration of saline, histamine, N-acetylcysteine (NAC) and lidocaine at room temperature (22 degrees C). RESULTS: There was a significant (P < 0.05) 14 +/- 3.8% decrease in LDF signal after 30 s, which lasted for 60-90 s, for all the substances applied at 22 degrees C. This pharmaco-independent vasoconstriction was further studied in patients under general anaesthesia (GA), with saline at 37 degrees C and after intranasal adrenaline treatment. While GA did not influence the vasoconstriction, saline at 37 degrees C and adrenaline pre-treatment abolished it. Nasal NO is influenced by vasoconstriction. Therefore we investigated, whether the observed vasoconstriction also changes nasal NO. A significant (P < 0.001) 8.03 +/- 0.59% decrease in nasal NO was recorded 60 s after administration of all the substances, and under GA after 22 degrees C saline application. This NO decrease was absent after intranasal adrenaline pre-treatment. An additional experiment tested the effect of nose blowing on nasal NO concentration. We registered an NO decrease with a similar pattern than observed with the other substances. CONCLUSIONS: Intranasal fluid nebulization at 22 degrees C induces a sympathetic mediated, transient vasoconstrictor reflex response. This somato-sympathetic vasoconstriction induces a decrease in nasal NO. Both could be related to the subjective comfort experienced by NACRS patients using intranasal saline sprays.

Comparison of neurotrophin and repellent sensitivities of early embryonic geniculate and trigeminal axons.

Geniculate (gustatory) and trigeminal (somatosensory) afferents take different routes to the tongue during rat embryonic development. To learn more about the mechanisms controlling neurite outgrowth and axon guidance, we are studying the roles of diffusible factors. We previously profiled the in vitro sensitivity of trigeminal axons to neurotrophins and target-derived diffusible factors and now report on these properties for geniculate axons. GDNF, BDNF, and NT-4, but not NT-3 or NGF, stimulate geniculate axon outgrowth during the ages investigated, embryonic days 12-14. Sensitivity to effective neurotrophins is developmentally regulated and different from that of the trigeminal ganglion. In vitro coculture studies revealed that geniculate axons were repelled by branchial arch explants that were previously shown to be repellent to trigeminal axons (Rochlin and Farbman [1998] J Neurosci 18:6840-6852). In addition, some branchial arch explants and untransfected COS7 cells repelled geniculate but not trigeminal axons. Sema3A, a ligand for neuropilin-1, is effective in repelling geniculate and trigeminal axons, and antineuropilin-1, but not antineuropilin-2, completely blocks the repulsion by arch explants that repel axon outgrowth from both ganglia. Sema3A mRNA is concentrated in branchial arch epithelium at the appropriate time to mediate the repulsion. In Sema3A knockout mice, geniculate and trigeminal afferents explore medial regions of the immature tongue and surrounding territories not explored in heterozygotes, supporting our previous hypothesis that Sema3A-based repulsion mediates the early restriction of sensory afferents away from midline structures.

[Correlation between objective criteria and subjective evaluation of symptoms in chronic rhinosinusitis]. / Corrélation entre des critères objectifs et l'évaluation subjective des symptômes dans la rhinosinusite chronique.

INTRODUCTION: We evaluated the possible correlations between the extent of inflammatory infiltration of the nasal mucosa caused by mechanical irritation (septal deviation and hypertrophy of the middle turbinate) and nasal airway resistance measured by rhinomanometry and acoustic rhinometry. Subjective evaluation of the nasal obstruction, rhinorrhoea and headache was done by visual analogic scale and compared with the inflammation. PATIENTS AND METHODS: 40 patients with a more than 18 months' history of chronic rhinosinusitis associated with septal deviation and/or hypertrophy of the middle turbinate were included in the study. The density of inflammatory cells (graded from + to +3, where + means few and +3 abundant inflammatory cells) in the mucosa of the middle turbinate was evaluated histopathologically. RESULTS: We found a significant correlation between subjective intensity of nasal obstruction and inflammation (mainly lymphocytes) of the middle turbinate mucosa and the value of nasal airway resistance measured by rhinomanometry. No correlation was found between the other parameters studied. CONCLUSION: Mechanical stimulation at the level of turbinoseptal contact causes inflammation in the mucosa which correlates with both subjective nasal airway resistance and rhinomanometry values.

Neuropilin-2 is required in vivo for selective axon guidance responses to secreted semaphorins.

Neuropilins are receptors for class 3 secreted semaphorins, most of which can function as potent repulsive axon guidance cues. We have generated mice with a targeted deletion in the neuropilin-2 (Npn-2) locus. Many Npn-2 mutant mice are viable into adulthood, allowing us to assess the role of Npn-2 in axon guidance events throughout neural development. Npn-2 is required for the organization and fasciculation of several cranial nerves and spinal nerves. In addition, several major fiber tracts in the brains of adult mutant mice are either severely disorganized or missing. Our results show that Npn-2 is a selective receptor for class 3 semaphorins in vivo and that Npn-1 and Npn-2 are required for development of an overlapping but distinct set of CNS and PNS projections.

[Study of the enzyme peptidyl peptidase IV in nasal mucosa]. / Etude de l'enzyme dipeptidyl peptidase IV dans la muqueuse nasale.

INTRODUCTION: The endothelial serine protease dipeptidyl peptidase IV (DPP IV) cleaves the tyrosin-prolin dipeptide of several inflammatory mediators and neuropeptides, including neuropeptide Y (NPY), yielding the endogenous Y2-receptor agonist NPY (3-36) which modulates sensory and parasympathetic nerve activity. The aims of the study were to investigate the localisation of DPP IV in human nasal mucosa and to measure in vitro activity of DPP IV in nasal mucosa biopsies from patients suffering from chronic rhinosinusitis. PATIENTS AND METHODS: Using immunohistochemistry we have studied the localisation of DPP IV in human nasal biopsies. The activity of DPP IV was measured in vitro in nasal mucosa samples obtained from 45 patients suffering from chronic rhinosinusitis and compared with the density of inflammatory cell infiltration. RESULTS: Positive immunoreactivity for DPP IV was observed in the human nasal mucosa. Low activity of DPP IV was associated with high density of inflammatory cells in the mucosa of patients suffering from chronic rhinosinusitis. The regressive correlation was statistically significant (p < 0.001). CONCLUSION: Low level DPP IV activity is associated with inflammation of the nasal mucosa. This enzyme may be involved in the pathophysiological mechanism of nasal hyperreactivity and chronic rhinosinusitis.

Ectopic adenoviral vector-directed expression of Sema3A in organotypic spinal cord explants inhibits growth of primary sensory afferents.

Sema3A (Sema III, SemD, collapsin-1) can induce neuronal growth cone collapse and axon repulsion of distinct neuronal populations. To study Sema3A function in patterning afferent projections into the developing spinal cord, we employed the recombinant adenoviral vector technique in embryonic rat spinal cord slices. Virus solution was injected in the dorsal aspect of organotypic spinal cord cultures with segmentally attached dorsal root ganglia (sc-DRG). In cultures grown in the presence of nerve growth factor (NGF), injected either with the control virus AdCMVLacZ or with vehicle only, afferent innervation patterns were similar to those of control. However, unilateral injection of AdCMVSema3A/AdCMVLacZ in sc-DRG slices revealed a strong inhibitory effect on NGF-dependent sensory afferent growth. Ectopic Sema3A in the dorsal spinal cord, the target area of NGF-responsive DRG fibers in vivo, created an exclusion zone for these fibers and as a result they failed to reach and innervate their appropriate target zones. Taken together, gain of Sema3A function in the dorsal aspect of sc-DRG cultures revealed a dominant inhibitory effect on NGF-dependent, nociceptive sensory DRG afferents, an observation in line with the model proposed by E. K. Messersmith et al. (1995, Neuron 14, 949-959), suggesting that Sema3A secreted by spinal cord cells can act to repel central sensory fibers during the formation of lamina-specific connections in the spinal cord.

Expression of the gene encoding the chemorepellent semaphorin III is induced in the fibroblast component of neural scar tissue formed following injuries of adult but not neonatal CNS.

This study evaluates the expression of the chemorepellent semaphorin III (D)/collapsin-1 (sema III) following lesions to the rat CNS. Scar tissue, formed after penetrating injuries to the lateral olfactory tract (LOT), cortex, perforant pathway, and spinal cord, contained numerous spindle-shaped cells expressing high levels of sema III mRNA. The properties of these cells were investigated in detail in the lesioned LOT. Most sema III mRNA-positive cells were located in the core of the scar and expressed proteins characteristic for fibroblast-like cells. Neuropilin-1, a sema III receptor, was expressed in injured neurons with projections to the lesion site, in a subpopulation of scar-associated cells and in blood vessels around the scar. In contrast to lesions made in the mature CNS, LOT transection in neonates did not induce sema III mRNA expression within cells in the lesion and was followed by vigorous axonal regeneration. The concomitant expression of sema III and its receptor neuropilin-1 in the scar suggests that sema III/neuropilin-1-mediated mechanisms are involved in CNS scar formation. The expression of the secreted chemorepellent sema III following CNS injury provides the first evidence that chemorepulsive semaphorins may contribute to the inhibitory effects exerted by scars on the outgrowth of injured CNS neurites. The vigorous regrowth of injured axons in the absence of sema III following early neonatal lesions is consistent with this notion. The inactivation of sema III in scar tissue by either antibody perturbation or by genetic or pharmacological intervention could be a powerful means to promote long-distance regeneration in the adult CNS.

Patterning of cortical efferent projections by semaphorin-neuropilin interactions.

Cortical neurons communicate with various cortical and subcortical targets by way of stereotyped axon projections through the white matter. Slice overlay experiments indicate that the initial growth of cortical axons toward the white matter is regulated by a diffusible chemorepulsive signal localized near the marginal zone. Semaphorin III is a major component of this diffusible signal, and cortical neurons transduce this signal by way of the neuropilin-1 receptor. These observations indicate that semaphorin-neuropilin interactions play a critical role in the initial patterning of projections in the developing cortex.