Injectable Hyaluronan-Based Thermoresponsive Hydrogels for Dermatological Applications

Most marketed HA-based dermal fillers use chemical cross-linking to improve mechanical properties and extend their lifetime in vivo; however, stiffer products with higher elasticity require an increased extrusion force for injection in clinical practice. To balance longevity and injectability, we propose a thermosensitive dermal filler, injectable as a low viscosity fluid that undergoes gelation in situ upon injection. To this end, HA was conjugated via a linker to poly(N-isopropylacrylamide) (pNIPAM), a thermosensitive polymer using "green chemistry", with water as the solvent. HA-L-pNIPAM hydrogels showed a comparatively low viscosity (G' was 105.1 and 233 for Candidate1 and Belotero Volume^®, respectively) at room temperature and spontaneously formed a stiffer gel with submicron structure at body temperature. Hydrogel formulations exhibited superior resistance against enzymatic and oxidative degradation and could be administered using a comparatively lower injection force (49 N and >100 N for Candidate 1 and Belotero Volume^®, respectively) with a 32G needle. Formulations were biocompatible (viability of L929 mouse fibroblasts was >100% and ~85% for HA-L-pNIPAM hydrogel aqueous extract and their degradation product, respectively), and offered an extended residence time (up to 72 h) at the injection site. This property could potentially be exploited to develop sustained release drug delivery systems for the management of dermatologic and systemic disorders.

Effect of Different Crosslinking Technologies on Hyaluronic Acid Behavior: A Visual and Microscopic Study of Seven Hyaluronic Acid Gels

BACKGROUND

The mechanical, rheological, and pharmacological properties of hyaluronic acid (HA) gels differ by their proprietary crosslinking technologies.<BR />

OBJECTIVE

To examine the different properties of a range of HA gels using simple and easily reproducible laboratory tests to better understand their suitability for particular indications.<BR />

METHODS AND MATERIALS

Hyaluronic acid gels produced by one of 7 different crosslinking technologies were subjected to tests for cohesivity, resistance to stretch, and microscopic examination. These 7 gels were: non-animal stabilized HA (NASHA® [Restylane®]), 3D Matrix (Surgiderm® 24 XP), cohesive polydensified matrix (CPM® [Belotero® Balance]), interpenetrating network-like (IPN-like [Stylage® M]), Vycross® (Juvéderm Volbella®), optimal balance technology (OBT® [Emervel Classic]), and resilient HA (RHA® [Teosyal Global Action]).<BR />

RESULTS

Cohesivity varied for the 7 gels, with NASHA being the least cohesive and CPM the most cohesive. The remaining gels could be described as partially cohesive. The resistance to stretch test confirmed the cohesivity findings, with CPM having the greatest resistance. Light microscopy of the 7 gels revealed HA particles of varying size and distribution. CPM was the only gel to have no particles visible at a microscopic level.<BR />

CONCLUSION

Hyaluronic acid gels are produced with a range of different crosslinking technologies. Simple laboratory tests show how these can influence a gel's behavior, and can help physicians select the optimal product for a specific treatment indication.<BR /><BR /> Versions of this paper have been previously published in French and in Dutch in the Belgian journal <EM>Dermatologie Actualité</EM>. Micheels P, Sarazin D, Tran C, Salomon D. Un gel d'acide hyaluronique est-il semblable à son concurrent? <EM>Derm-Actu</EM>. 2015;14:38-43.<BR /><BR /> <EM>J Drugs Dermatol. 2016;15(5):600-606.</EM>.

Hyaluronic Acid Filler in HIV-Associated Facial Lipoatrophy: Evaluation of Tissue Distribution and Morphology with MRI

OBJECTIVE

This prospective observational study evaluated magnetic resonance imaging (MRI) findings of hyaluronic acid (HA) injections used for the correction of HIV-associated facial lipoatrophy.

METHODS

Ten consecutive males underwent subdermal HA injection (mean 1.3 ± 0.6 ml per side) and MRI examinations prior to and then 1, 6 and 12 months after injection. Two radiologists blinded to the clinical data assessed morphologic and quantitative changes.

RESULTS

MRI revealed HA deposition in the subdermal and deep fat compartments. A significant HA volume increase was observed 1 month after injection (mean increase 331%, p < 0.0001) as compared to the injected amount. No volume reduction occurred at 12 months (p = 0.9961). The measured bound water content did not change (p > 0.9991), whereas skin thickness and tissue vascularization increased during the first 6 months (p = 0.01).

CONCLUSION

Our data show that the cosmetic results of HA injections are caused by water binding in the deep facial fat and by a transient increase in vascularization and skin thickness.

Psychiatric blood biomarkers: avoiding jumping to premature negative or positive conclusions

Blood biomarkers may provide a scientifically useful and clinically usable peripheral signal in psychiatry, as they have been doing for other fields of medicine. Jumping to premature conclusions, negative or positive, can create confusion in this field. Reproducibility is a hallmark of good science. We discuss some recent examples from this dynamic field, and show some new data in support of previously published biomarkers for suicidality (SAT1, MARCKS and SKA2). Methodological clarity and rigor in terms of biomarker discovery, validation and testing is needed. We propose a set of principles for what constitutes a good biomarker, similar in spirit to the Koch postulates used at the birth of the field of infectious diseases.

Cntnap4 differentially contributes to GABAergic and dopaminergic synaptic transmission

Although considerable evidence suggests that the chemical synapse is a lynchpin underlying affective disorders, how molecular insults differentially affect specific synaptic connections remains poorly understood. For instance, Neurexin 1a and 2 (NRXN1 and NRXN2) and CNTNAP2 (also known as CASPR2), all members of the neurexin superfamily of transmembrane molecules, have been implicated in neuropsychiatric disorders. However, their loss leads to deficits that have been best characterized with regard to their effect on excitatory cells. Notably, other disease-associated genes such as BDNF and ERBB4 implicate specific interneuron synapses in psychiatric disorders. Consistent with this, cortical interneuron dysfunction has been linked to epilepsy, schizophrenia and autism. Using a microarray screen that focused upon synapse-associated molecules, we identified Cntnap4 (contactin associated protein-like 4, also known as Caspr4) as highly enriched in developing murine interneurons. In this study we show that Cntnap4 is localized presynaptically and its loss leads to a reduction in the output of cortical parvalbumin (PV)-positive GABAergic (γ-aminobutyric acid producing) basket cells. Paradoxically, the loss of Cntnap4 augments midbrain dopaminergic release in the nucleus accumbens. In Cntnap4 mutant mice, synaptic defects in these disease-relevant neuronal populations are mirrored by sensory-motor gating and grooming endophenotypes; these symptoms could be pharmacologically reversed, providing promise for therapeutic intervention in psychiatric disorders.

Correlations between photoactivable porphyrins' fluorescence, erythema and the pain induced by PDT on normal skin using ALA-derivatives

BACKGROUND

Photodynamic therapy (PDT) with precursors of photoactivable porphyrins is a well-established treatment modality for skin pathologies as well as hair removal. Pain is a major side effect thereof, and it affects the treatment compliance and acceptance.

METHODS

Five male subjects underwent a PDT procedure on normal skin, either with a diode laser (635 nm) or a lamp (405 nm), 3 or 6h after application of various precursors of photoactivable porphyrins (ALA 1M; Metvix(®) 1M; ALA-DGME 1M; ALA-DGME 3.66 M). Light doses ranged from 30 to 150 J/cm(2) and irradiances were 100 or 180 mW/cm(2). Fluorescence measurements were performed just before PDT, pain was quantified during PDT, and erythema was determined 24h afterwards.

RESULTS

Because precursor ALA-DGME was very selective for the pilosebaceous apparatus vs. the epidermis, we solely carried out the PDTs using this precursor. In the absence of light, no pain was reported. An increase in pain was observed when increasing the irradiance. A correlation was observed between the follicular fluorescence and the maximal pain score during PDT. A correlation was observed between follicular fluorescence and skin erythema, and between pain score and skin erythema.

CONCLUSIONS

With our well-controlled PDT parameters and homogenous subjects' conditions, we showed that pain could be reduced by reducing irradiance during PDT procedures. With the various correlations observed, we conclude that both pain and PaP fluorescence are useful tools to predict the post-PDT tissue effects (side effects and outcome). We suggest that A∂ nerve fibres would be the best candidate as first generators of PDT-induced pain.

Immunohistochemical detection of ribonucleotide reductase in human breast-tumors

Ribonucleotide reductase (RNR) consists of two non-identical subunits, R1 and R2 and is one of the key enzymes involved in DNA biosynthesis. RNR activity is considerably higher in malignant tumors than in normal tissues in the rat suggesting that RNR may play an important role in the pathogenesis of human tumors. In order to obtain immunological reagents to study the localization and level of expression of RNR in various human tissues, a synthetic peptide containing sequences corresponding to the COOH-terminal region of the human R2 subunit was used to generate rat monoclonal antibodies. The generated rat monoclonal antibodies (IgG) inhibited RNR enzymatic activity purified from murine P388 leukemia cells. These antibodies were used to immunohistochemically examine the distribution of RNR in a small panel of 8 malignant and 4 benign human breast tumors. Positive immunostaining for RNR was observed in the cytoplasm of human breast carcinoma cells in which a specific 44 kDa specific band of R2 subunit was also detected by Western blot analysis. The immunostaining was blocked by preabsorption of the antibody with an excess amount of the synthetic peptide immunogen. In 8 of 8 breast carcinomas, positive immunostaining for the R2 subunit was observed whereas noninvolved, adjacent breast tissue showed no staining with this antibody. In addition, few of the benign breast lesions exhibited staining with this antibody. These data indicate that these antibodies can immunohistochemically detect RNR in frozen or formalin-fixed, paraffin- embedded tissues and that there is a differential expression of RNR between breast tumors and non-involved breast tissue. Immunohistochemical detection of RNR using these antibodies may therefore be useful for the diagnosis of human breast tumors.

Immunohistochemical detection of cripto-1, amphiregulin and transforming growth-factor-alpha in human gastric carcinomas and intestinal metaplasias

The expression and localization of cripto-1 (CR-1), amphiregulin (AR) and transforming growth factor alpha (TGFalpha) were assessed by immunocytochemistry in 37 primary human gastric tumors, 30 noninvolved gastric mucosa samples that were adjacent to carcinoma but exhibited intestinal metaplasia and 37 adjacent, noninvolved gastric mucosa samples. Seventeen (46%), nineteen (51%) and twenty-one (57%) carcinomas showed staining for CR-1, AR and TGFalpha, respectively; whereas sixteen (53%), eight (26%) and five (17%) intestinal metaplasias were reactive with the anti-CR-1, anti-AR and anti-TGFalpha antibodies, respectively. In contrast, none of the normal, noninvolved gastric mucosa samples reacted with the TGFalpha antibody and only 1 (3%) of these samples showed weak staining with the anti-CR-1 antibody. However, 8 (21%) of the normal gastric mucosa samples showed moderate levels of staining with the AR antibody. Within the carcinomas, there was a slight trend for association between TGFalpha and CR-1 expression (p<0.05), but no correlation was found between epidermal growth factor receptor and CR-1 expression. Staining for p53 was observed in 26 (70%) of the carcinomas, 3 (10%) intestinal metaplasias and none of the gastric mucosa samples. This data demonstrate that CR-1, like TGFalpha, may be a tumor marker for a subset of gastric carcinomas in addition to being an important factor in the early stages of gastric cancer development.

Convergent functional genomics of schizophrenia: from comprehensive understanding to genetic risk prediction

We have used a translational convergent functional genomics (CFG) approach to identify and prioritize genes involved in schizophrenia, by gene-level integration of genome-wide association study data with other genetic and gene expression studies in humans and animal models. Using this polyevidence scoring and pathway analyses, we identify top genes (DISC1, TCF4, MBP, MOBP, NCAM1, NRCAM, NDUFV2, RAB18, as well as ADCYAP1, BDNF, CNR1, COMT, DRD2, DTNBP1, GAD1, GRIA1, GRIN2B, HTR2A, NRG1, RELN, SNAP-25, TNIK), brain development, myelination, cell adhesion, glutamate receptor signaling, G-protein-coupled receptor signaling and cAMP-mediated signaling as key to pathophysiology and as targets for therapeutic intervention. Overall, the data are consistent with a model of disrupted connectivity in schizophrenia, resulting from the effects of neurodevelopmental environmental stress on a background of genetic vulnerability. In addition, we show how the top candidate genes identified by CFG can be used to generate a genetic risk prediction score (GRPS) to aid schizophrenia diagnostics, with predictive ability in independent cohorts. The GRPS also differentiates classic age of onset schizophrenia from early onset and late-onset disease. We also show, in three independent cohorts, two European American and one African American, increasing overlap, reproducibility and consistency of findings from single-nucleotide polymorphisms to genes, then genes prioritized by CFG, and ultimately at the level of biological pathways and mechanisms. Finally, we compared our top candidate genes for schizophrenia from this analysis with top candidate genes for bipolar disorder and anxiety disorders from previous CFG analyses conducted by us, as well as findings from the fields of autism and Alzheimer. Overall, our work maps the genomic and biological landscape for schizophrenia, providing leads towards a better understanding of illness, diagnostics and therapeutics. It also reveals the significant genetic overlap with other major psychiatric disorder domains, suggesting the need for improved nosology.

Quantification of surviving cerebellar granule neurones and abnormal prion protein (PrPSc) deposition in sporadic Creutzfeldt-Jakob disease supports a pathogenic role for small PrPSc deposits common to the various molecular subtypes

AIMS

Neuronal death is a major neuropathological hallmark in prion diseases. The association between the accumulation of the disease-related prion protein (PrP(Sc) ) and neuronal loss varies within the wide spectrum of prion diseases and their experimental models. In this study, we investigated the relationships between neuronal loss and PrP(Sc) deposition in the cerebellum from cases of the six subtypes of sporadic Creutzfeldt-Jakob disease (sCJD; n=100) that can be determined according to the M129V polymorphism of the human prion protein gene (PRNP) and PrP(Sc) molecular types.

METHODS

The numerical density of neurones was estimated with a computer-assisted image analysis system and the accumulation of PrP(Sc) deposits was scored.

RESULTS

The scores of PrP(Sc) immunoreactive deposits of the punctate type (synaptic type) were correlated with neurone counts - the higher the score the higher the neuronal loss - in all sCJD subtypes. Large 5- to 50-µm-wide deposits (focal type) were found in sCJD-MV2 and sCJD-VV2 subtypes, and occasionally in a few cases of the other studied groups. By contrast, the highest scores for 5- to 50-µm-wide deposits observed in sCJD-MV2 subtype were not associated with higher neuronal loss. In addition, these scores were inversely correlated with neuronal counts in the sCJD-VV2 subtype.

CONCLUSIONS

These results support a putative pathogenic role for small PrP(Sc) deposits common to the various sCJD subtypes. Furthermore, the observation of a lower loss of neurones associated with PrP(Sc) type-2 large deposits is consistent with a possible 'protective' role of aggregated deposits in both sCJD-MV2 and sCJD-VV2 subtypes.

A randomized, controlled trial validates a peripheral supra-additive antihyperalgesic effect of a paracetamol-ketorolac combination

The combination of paracetamol with non-steroidal anti-inflammatory drugs (NSAIDs) is widely used; however, the nature and mechanism of their interaction are still debated. A double-blind, pharmacokinetic/pharmacodynamic, randomized, cross-over, placebo-controlled study was carried out in human healthy volunteers. The aim was to explore the existence of a positive interaction between paracetamol 1 g and ketorolac 20 mg administered intravenously on experimental pain models in human beings. The effects of the paracetamol-ketotolac combination were compared with similar doses of respective single analgesic and to placebo on the sunburn model (UVB-induced inflammation), cold pain tolerance and the nociceptive flexion reflex. The kinetics of the plasma concentrations of paracetamol and ketorolac were measured using 2D-liquid chromatography-mass spectrometry. Thirteen volunteers were screened, and 11 completed the study. Ketorolac significantly decreased primary hyperalgesia to heat stimuli compared with paracetamol (p < 0.014). The combination performed better than paracetamol (p < 0.001) and placebo (p < 0.042), increasing heat pain threshold by 1.5°C. The combination radically reduced primary hyperalgesia to mechanical stimulation (39%) compared with placebo (p < 0.002) and single agents (paracetamol p < 0.024 and ketorolac p < 0.032). The combination also reduced, slightly although significantly, the intensity of pain (10%) for the cold pressor test (versus placebo: p < 0.012, paracetamol: p < 0.019 and ketorolac p < 0.004). None of the treatments significantly affected the central models of pain at this dosage level. No pharmacokinetic interactions were observed. These results suggest a supra-additive pharmacodynamic interaction between paracetamol and ketorolac in an inflammatory pain model. The mechanism of this interaction could mainly rely on a peripheral contribution of paracetamol to the effect of NSAIDs.

[Lentigo maligna: a special melanoma]

Lentigo maligna (LM) and lentigo maligna melanoma (LMM) account for about 10% of all melanomas. They have distinct clinical and histological features as well as specific epidemiology, natural history, evolution, and genetics. Epidemiology of these tumors progressively concerns younger patients. Diagnostic and preparation of surgical removal of LM and LMM can now be optimized by new technologies of imaging, like dermoscopy or in vivo confocal reflectance microscopy. Surgery is the treatment of choice, but alternative options can be considered, especially for the elderly for whom the needs for efficiency and acceptability should be met.

[Evaluations and measures in dermatology: new approaches]

Advances in computing and digital imaging now make it possible to photograph and compare skin lesions at regular intervals. It is also possible to measure changes in the skin and observing the skin in vivo at the microscopic level. This article presents some of these techniques that are passed from the world of research to the clinic to monitor or diagnose melanocytic lesions.

Kaposi's sarcoma after repeated surgical procedures in an immunocompetent patient: the lymphatic hypothesis

A 63-year-old Swiss patient developed acquired nodules on his right palm after 3 localized surgeries, called 'needle fasciotomy', for Dupuytren's disease. Kaposi's sarcoma (KS) was diagnosed in a biopsy of a nodule. A positive immunolabeling and serology for human herpesvirus 8 has been found, but human immunodeficiency virus and hepatitis C identification remained negative. The nodules were limited to the surgically traumatized area. This first report of a nonimmunocompromised patient developing a KS after repeated surgeries in a unique peculiar localized area with a dense lymphatic network sustains the hypothesis that tissue alterations involving the lymphatic system could play a central role in the occurrence of KS.

[Honey: from Noe to wound care]

Honey with its high concentration of sugar constitute a hyperosmotic medium with antimicrobial properties. It contains different enzymes, including glucose-oxidase that generates hydrogen peroxide and gluconic acid in the presence of glucose and water. The viscosity and the hygroscopic qualities of honey permits its even spread on the wound bed, creating a favourable environment for wound healing. With these properties, honey when adequately prepared, is an efficient treatment of chronic wounds of the lower leg and also of abdominal wounds.

[Epidemiological surveillance of Creutzfeldt-Jakob in France]

INTRODUCTION

Transmissible spongiform encephalopathies (TSE) have been under epidemiological surveillance in France and in Europe since the early 1990s. The observation of iatrogenic Creutzfeldt-Jakob disease (CJD), the outbreak of bovine spongiform encephalopathy (ESB) and its probable transmission to many species gave rise to the surveillance which remains warranted by the emergence of a variant of CJD (vCJD), in 1996.

STATE OF ART

In France, epidemiological surveillance is coordinated by the InVS which receives input from cases notifications addressed to INSERM Unit 708 directly by clinicians or more often following requests for 14-3-3 detection in CSF. All suspected cases are followed up until a final diagnosis is established. Thanks to the effectiveness of the French network of neuropathology, autopsies are performed in more than half of patients who die with a diagnosis of suspected CJD. Diagnostic criteria allow comparison of the incidence of the different forms of the disease in all countries with a system of surveillance. Sporadic CJD is the most frequent form of the disease with more than 80% of the cases. Its origin remains unknown. To date, cases of iatrogenic CJD referred to the French surveillance network have been caused by dura mater grafts or human growth hormone treatments administrated in the 1980s. Ten percent of TSE are of genetic origin with an autosomic dominant transmission of a mutation or an insertion located on the PRNP gene. The most recent form of the disease is vCJD which is a new form, first described in the United Kingdom in 1994.

PROSPECT AND CONCLUSION

Active epidemiological surveillance remains a timely issue, particularly in France, because of the development of new cases of iatrogenic CJD after human growth hormone treatment. It is of importance in France and worldwide because of the emergence of post-transfusional cases of vCJD and the possible appearance of vCJD in persons with valine-valine or methionine-valine genotypes at codon 129.

[Focal hyperhidrosis: disease characteristics and treatments]

Hyperhidrosis is a disease defined by the eccrine sweat glands production exceeding the needs of thermoregulation. In most of the cases there is no underlying disease and hyperhidrosis is characterised by an intense sweating or flow in the axillae or palms. Hyperhidrosis results in an important psychologic effect that can lead to a major socio-professional impairement. In the severe forms of hyperhidrosis, conservative treatments often are disappointing. Botulinum toxin is a successful treatment used in hyperhidrosis for more than ten years. It is an important therapeutic discovery that leads to a dramatic decrease of sweat and to quick improvement in the quality of life.

Efficacy and tolerance of a hydrocolloid dressing containing hyaluronic acid for the treatment of leg ulcers of venous or mixed origin

OBJECTIVE

This study was aimed at comparing efficacy and tolerance of a new hydrocolloid dressing containing hyaluronic acid (HC + HA) to a reference hydrocolloid not containing hyaluronic acid (HC) in the treatment of leg ulcers of venous or mixed origin.

RESEARCH DESIGN AND METHODS

This was an open, prospective study, randomized in parallel groups, in which 125 patients were enrolled and treated for up to 42 days. The primary efficacy criterion was the reduction of the wound area; other efficacy criteria were the condition of the wound bed, and of the surrounding skin, and presence and severity of symptoms such as pain and itching.

RESULTS

After 42 days of treatment the median reduction of ulcer area was -42.6% (95% confidence interval [CI]: -66.6; -5.7) and -31.0% (95% CI: -51.6; -8.8) in the HC + HA group and in the reference HC group, respectively. The difference between treatments was not statistically significant. A reduction > or = 90% of the initial ulcer area was seen in 15 patients in the HC + HA dressing group and in only seven patients in the HC dressing group. Changes in wound bed condition in the two groups were not significantly different, except for a more marked reduction of fibrinous tissue in the HC + HA dressing group (p = 0.04), at Day 28. Both treatments were well tolerated.

CONCLUSIONS

The HC + HA dressing was equally well tolerated and with a trend to be more effective than the reference HC dressing in the treatment of leg ulcers of venous or mixed origin. Further research is needed to confirm these findings.

Treatment with an Interleukin 1 beta antibody improves glycemic control in diet-induced obesity

The proinflammatory cytokine Interleukin 1 beta (IL-1beta) is elevated in obese individuals and rodents and it is implicated in impaired insulin secretion, decreased cell proliferation and apoptosis of pancreatic beta cells. In this study we describe the therapeutic effects by an IL-1beta antibody to improve glucose control in hyperglycemic mice with diet-induced obesity. After 13 weeks of treatment the IL-1beta antibody treated group showed reduced glycated hemoglobin (( *)P=0.049), reduced serum levels of proinsulin (( *)P=0.015), reduced levels of insulin and smaller islet size (( *)P=1.65E-13) relative to the control antibody treated group. Neutralization of IL-1beta also significantly reduced serum amyloid A (SAA) which is an indicator of inflammation-induced acute phase response (( *)P=0.024). While there was no improvement of obesity, a significant improvement of glycemic control and of beta cell function is achieved by this pharmacological treatment which may slow/prevent disease progression in Type 2 Diabetes.

Comparison of ALA- and ALA hexyl-ester-induced PpIX depth distribution in human skin carcinoma

Photodynamic therapy (PDT) based on the use of photoactivable porphyrins, such as protoporphyrin IX (PpIX), induced by the topical application of amino-levulinic acid (ALA) or its derivatives, ALA methyl-ester (m-ALA), is a treatment for superficial basal cell carcinoma (BCC), with complete response rates of over 80%. However, in the case of deep, nodular-ulcerative lesions, the complete response rates are lower, possibly related to a lower bioavailability of PpIX. Previous in vitro skin permeation studies demonstrated an increased penetration of amino-levulinic acid hexyl-ester (h-ALA) over ALA. In this study, we tested the validity of this approach in vivo on human BCCs. An emulsion containing 20% ALA (w/w) and preparations of h-ALA at different concentrations were applied topically to the normal skin of Caucasian volunteers to compare the PpIX fluorescence intensities with an optical fiber-based spectrofluorometer. In addition, the PpIX depth distribution and fluorescence intensity in 26 BCCs were investigated by fluorescence microscopy following topical application of 20% ALA and 1% h-ALA. We found that, for application times up to 24h, h-ALA is identical to ALA as a PpIX precursor with respect to PpIX fluorescence intensity, depth of penetration, and distribution in basal cell carcinoma, but has the added advantage that much smaller h-ALA concentrations can be used (up to a factor 13). We observed a non-homogenous distribution in BCCs with both precursors, independent of the histological type and depth of invasion in the dermis.

Effect of intense pulsed-light exposure on lipid peroxides and thymine dimers in human skin in vivo

BACKGROUND

Intense pulsed light (IPL) generates high-intensity short flashes of visible light and has been used for about 10 years to improve dermatological conditions such as telangiectasia, pigmented lesions, and skin aging. Although these systems deliver a moderate dose (10-30 J/cm(2)) of visible light, this dose is delivered during a short pulse (2-5 milliseconds), which implies a very high fluence rate (approximately 4000 W/cm(2)). For this reason, we speculated whether the Bunsen-Roscoe law of reciprocity could still be valid in these conditions.

OBSERVATIONS

Nine healthy volunteers were exposed to IPL or UV-A or simulated solar UV radiation, and then thymine dimer and lipid peroxide concentrations were determined in skin biopsy specimens of the exposed sites. Only exposure to solar UV radiation (7-J/cm(2) UV-A + 80-mJ/cm(2) UV-B) produced measurable amounts of thymine dimers in DNA from skin biopsy specimens, whereas UV-A radiation (40 J/cm(2)) and IPL (9 J/cm(2)) induced 3-fold and 6-fold increases of cutaneous lipid peroxides, respectively.

CONCLUSIONS

These preliminary results indicate that IPL, although filtered for wavelengths shorter than 500 nm, can generate oxidative stress, a typical hallmark of UV-A, but does not induce thymine dimers. This emphasizes the need for long-term studies involving IPL before using this technique in a recurrent manner.

Épidémiologie de la variante de la maladie de Creutzfeldt-Jakob en France

Variant Creutzfeldt-Jakob disease (vCJD) is the only form of prion diseases linked to bovine spongiform encephalopathy (BSE). The disease was first described in the United-Kingdom (UK) and France is the second affected country with 21 cases. Clinical, genetic and neuropathological features are the same in both countries. Comparison of the total number of cases in France and in the UK, according to dates of onset, shows that, in France, the maximum incidence seems to be five years delayed and that, in the UK, the number of vCJD cases regularly decreases since 1999. Delayed exposure to contaminated beef products in France compared to the UK could explain this temporal gap. Three cases of vCJD after transfusion of labile blood products were observed in the UK. No such of cases were observed in France but three patients developing signs of vCJD in 2004 were blood donors. A total of 42 recipients were identified with 17 recipients still alive.

Kit and PDGFR-alpha activities are necessary for Notch4/Int3-induced tumorigenesis

Transgenic mice overexpressing Notch4 intracellular domain (Int3) under the control of the whey acidic protein (WAP) or mouse mammary tumor virus-long terminal repeat promoters, develop mammary tumors. Microarray analysis of these tumors revealed high levels of c-Kit expression. Gleevec is a tyrosine kinase inhibitor that targets c-Kit, platelet-derived growth factor receptors (PDGFRs) and c-Abl. This led us to speculate that tyrosine kinase receptor activity might be a driving force in the development of Int3 mammary tumors. WAP-Int3 tumor-bearing mice were treated with continuous release of Gleevec using subcutaneously implanted Alzet pumps. Phosphorylation of c-Kit, PDGFRs and c-Abl is inhibited in Int3 transgenic mammary tumors by Gleevec. Inhibition of these enzymes is associated with a decrease in cell proliferation and angiogenesis, and an induction of apoptosis. To examine the signaling mechanisms underlying Notch4/Int3 tumorigenesis, we employed small interfering RNA (siRNA) to knock down c-Kit, PDGFRs and c-Abl alone or in combination and observed the effects on soft agar growth of HC11 cells overexpressing Int3. Only siRNA constructs for c-Kit and/or PDGFR-alpha were able to inhibit HC11-Int3 colony formation in soft agar. Our data demonstrate an inhibitory effect of Gleevec on Int3-induced transformation of HC11 cells and mammary tumors and indicate an oncogenic role for c-Kit and PDGFR-alpha tyrosine kinases in the context of Int3 signaling.

Multiple cutaneous osteomas of the face associated with chronic inflammatory acne

Multiple miliary osteoma cutis of the face represents a rare and frequently unrecognized complication of chronic inflammatory acne. Their differentiation from microcomedones and macrocomedones may be challenging. The case of a 46-year-old Asian woman who suffered from chronic inflammatory acne is described. She had multiple papular lesions of the cheeks that did not respond to various topical and systemic therapies including oral isotretinoin. Light microscopy studies as well as ultrasound and computed tomography (CT) scan investigations demonstrated the presence of multiple osteoma cutis. Needle microincisions followed by mechanical extirpation of the bony formation resulted in a considerable cosmetic improvement of her skin disease. Knowledge of this rare complication of acne is mandatory, as its treatment is different from that of retentional and inflammatory acne and frequently relies on surgical modalities. Our novel technique consisting of needle microincisions with curettage of the lesions is simple and safe, leading to good cosmetic results.