Elicitation of Stilbenes and Benzofuran Derivatives in Hairy Root Cultures of White Mulberry (Morus alba)

Stilbene and benzofuran derivatives isolated from the root of white mulberry (Morus alba) have shown various biological activities, including anti-inflammatory, antioxidant, and antimicrobial properties. The objectives of this study were to develop hairy root cultures and assess the effect of multiple elicitors combinations including (I) methyl-β-cyclodextrin (CD), MgCl₂, methyl jasmonate (MeJA), and H₂O₂, (II) CD, MgCl₂, and MeJA and (III) CD, MgCl_2, and H₂O₂, on the production of these bioactive compounds. The highest yields of stilbenes and benzofurans were obtained upon co-treatment with 18 g/L CD, 3 mM H₂O₂ and 1 mM MgCl₂. The stilbenes oxyresveratrol, resveratrol, and 3'-prenylresveratrol accumulated up to 6.27, 0.61, and 5.00 mg/g DW root, respectively. Meanwhile, the aryl benzofurans moracin M and moracin C accumulated up to 7.82 and 1.82 mg/g DW root, respectively. These stilbenes and benzofurans accumulated in the culture medium of the elicited hairy root cultures. They were not detected in the root tissue. However, the oxyresveratrol diglucoside mulberroside A was only detected in the root tissue with yields up to 10.01 mg/g DW. The results demonstrated that co-treatment of white mulberry hairy root cultures with multiple elicitors can significantly enhance production and secretion of stilbenes and benzofurans in this controlled and sustainable axenic culture system.

Cometary science. The organic-rich surface of comet 67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta

The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 ± 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kÅ(-1)), and the broad absorption feature in the 2.9-to-3.6-micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun.

Seminal fluid promotes in vitro sperm-oviduct binding in the domestic cat (Felis catus)

From many endangered or threatened species which are expected to profit from assisted reproduction techniques, mainly epididymal sperm of dead or freshly castrated males are available. These sperm had contact to epididymal secretion products but not to seminal fluid components. Notably, products of accessory sex glands have been shown in domestic animals to condition sperm for fertilization, in particular by mediating sperm-oviduct interaction. We report for the first time that motile epididymal sperm from domestic cats are able to bind to fresh oviduct epithelial cell explants from preovulatory females (median [min, max] of 10 [8, 16] and 10 [8, 17] sperm per 0.01 mm(2) explant surface from both isthmic and ampullar regions, respectively). More sperm attach to the explants when epididymal sperm were preincubated for 30 minutes with seminal fluid separated from electroejaculates of mature tomcats (median [min, max] of 17 [13, 25] and 16 [12, 21] sperm per 0.01 mm(2) explant surface from isthmus and ampulla, respectively). The proportion of bound sperm increased from a median of 54% to 62% by seminal fluid treatment. Sperm-oviduct binding could be facilitated by the decelerated sperm motion which was observed in seminal fluid-treated samples or supported by seminal fluid proteins newly attached to the sperm surface. Seminal fluid had no effect on the proportion of sperm with active mitochondria. Extent and pattern of sperm interaction in vitro were independent of explant origin from isthmus or ampulla. Sperm were attached to both cilia and microvilli of the main epithelial cell types present in all explants. In contrast to published sperm-binding studies with porcine and bovine oviduct explants where predominantly the anterior head region of sperm was attached to ciliated cells, the tails of some cat sperm were firmly stuck to the oviduct cell surfaces, whereas the heads were wobbling. Whether this response is a preliminary step toward phagocytosis or a precondition to capacitation and fertilization remains to be determined. In conclusion, treatment of epididymal sperm with seminal fluid or particular protein components should be considered in future investigations for its potential to improve the outcome of artificial insemination in felids.

Effects of chemical stress and food limitation on the energy reserves and growth of turbot, Scophthalmus maximus

The objective of the present study is to examine the growth and energetic performance of juvenile turbot after exposure to contaminated sediment and during the subsequent recovery period with or without food limitation. We designed a two-step experiment by first exposing juvenile turbot to harbour sediment for 26 days and then transferring them to clean sea water with different frequencies of feeding for 35 days. Without food limitation, fish previously exposed to contaminated sediment compensated for weight, length and lipid reserve losses; we did not record any differences in size, Fulton's K condition index and triacylglycerol/sterol (TAG/ST) ratio after the 35-day depuration period compared to the reference fish. This result could be related to the compensatory growth mechanism observed in a wide range of fish species following a period of growth depression. With food limitation during the 35-day depuration period, recovery growth was not sufficient to restore length and weight values similar to the reference fish. Moreover, turbot previously exposed to contaminated sediment and subsequently fed twice or once a week exhibited extremely low TAG/ST ratios, but the reference fish submitted to the same restrictive feeding conditions did not. This study indicates that juvenile fish affected by chemical pollution can improve their biological performance if pollution events are followed by a period of abundant food. However, if pollution events occur during periods of food scarcity, e.g. in winter, storage of energy reserves will be compromised.

How to help the skin cope with glycoxidation

BACKGROUND

Protein glycation refers to the spontaneous reaction of reducing sugars with proteins and the subsequent formation of stable advanced glycation end products (AGEs). Glycation is linked with oxidative stress, and this association is called "glycoxidation". Glycoxidation alters the protein structure and function and causes tissue aging, as seen in human skin. Therefore, research on substances inhibiting glycoxidation appears to be crucial in the prevention of skin aging. With this aim, several plant extracts have been screened for antiglycation activity, and the results of the best candidates are presented in this article.

METHODS

Glycation was studied on human skin proteins (collagen, elastin, and albumin) and on a model of reconstructed skin. Oxidative stress has been addressed by testing the copper-induced low-density lipoprotein oxidation, ultraviolet irradiation of glycated dermis, and carbonyl activation of human dermal fibroblasts. A clinical test evaluated the extent of oxidative stress induced by ultraviolet A irradiation.

RESULTS

Among the tested products, several plant extracts have decreased the glycation effects on skin proteins collagen, elastin, and albumin. In addition, a plant extract has significantly inhibited the different forms of oxidative stress associated with protein glycation.

CONCLUSIONS

We have demonstrated that plant extracts can relieve the deleterious effects of glycation on human skin. Moreover, a plant extract rich in antioxidant molecules has also significantly preserved the human skin from glycoxidation attacks.

A combined measurement of metal bioaccumulation and condition indices in juvenile European flounder, Platichthys flesus, from European estuaries

Condition indices and metal bioaccumulation of early life stages of juvenile flounder (5-10 cm) were determined in three anthropogenic estuaries (the Scheldt, Seine and Loire) and compared to a reference site (the Canche). Significant correlations were found between metal concentrations in sediment and (i) fish liver for Cd, Cu, Ni, Pb, V and Zn and (ii) fish gills for Cd and Mn. Metal accumulation in juvenile flounder from the three anthropogenic estuaries coincided with significantly lower Fulton's K indices (from 0.99 ± 0.03 to 1.06 ± 0.01 mg mm(-3)) compared to those from the Canche estuary (from 1.02 ± 0.01 to 1.13 ± 0.01 mg mm(-3)). This discrepancy in fish condition index increased with fish size and therefore, strongly depends on the time juvenile spend in estuary. Muscle lipid contents and Triacylglycerol to Sterol ratios were significantly lower in fish collected in the Scheldt (lipid content: 21.3 ± 3.6%), Seine (17.9 ± 19.8%) and Loire (19.5 ± 2.4%) estuaries compared to those originating from the Canche (38.3 ± 4.6%). This study highlights that combined measures of both fish metal contents and condition indices gives a relevant assessment of juvenile fish health growing in anthropogenic estuaries.

A multibiomarker approach in juvenile turbot, Scophthalmus maximus, exposed to contaminated sediments

Juvenile turbot were exposed in laboratory conditions to a mixture of chemical contaminants associated with harbour and estuarine sediments for seven and 21 days. Several molecular biomarkers of exposure were then measured in fish liver: two biotransformation parameters [ethoxyresorufin-O-deethylase (EROD) and phase II glutathione S-transferase (GST) activities] and an antioxidant enzyme activity [catalase (CAT)]. Modifications at the histological level were analysed by the measurement of the number and size of melanomacrophage centres (MMCs) and disturbances to the immune function by the measurement of cytokine transforming growth factor-beta (TGF-β) and development of the thymus. The responses of these molecular and immunological biomarkers were correlated with metal and PAH concentrations measured in sediments and with the physiological performance of turbot analysed in a previous study on the same fish (growth rates, condition factor K, RNA:DNA ratio and lipid index). While no difference was found in thymus analysis, some molecular and immunological responses were observed in fish exposed to contaminated sediments. Weak relationships between molecular biomarkers' responses and PAH concentrations were recorded, while their responses were significantly correlated with some metals. MMC and aggregates were weakly related to chemical contaminants whereas some significant correlations were found between TGF-b1 responses and some metal concentrations. However, molecular and immunological biomarkers were weakly related to fish physiological damages since low responses were observed in the condition which led to the lowest growth and condition indices. These data suggest the complexity of cause-effect relationships between exposure to pollutants, metabolisms and health damages. Precautions should be considered in the use of molecular and immunological biomarkers alone in biomonitoring programs. Their complementary use with physiological biomarkers, such as fish growth and condition indices, could improve their utilisation.

Responses of juvenile sea bass, Dicentrarchus labrax, exposed to acute concentrations of crude oil, as assessed by molecular and physiological biomarkers

In the present study, juvenile sea bass were exposed for 48 and 96 h to an Arabian light crude oil and their responses were assessed at the molecular and physiological levels. The aim of the study was therefore to assess (i) the short term effects of crude oil exposure by the measurement of several molecular biomarkers, (ii) the consequences of this short term exposure on fish health by using growth and condition indices measured after a decontamination period of 28 and 26 d in seawater. Hydrocarbon petroleum concentrations was monitored during the 96 h experiments and an increase of PAH concentrations were found in fish following both exposure times. An 7-ethoxyresorufin-O-deethylase (EROD) induction was observed after 48 h of exposure, while a significant decrease in the sea bass specific growth rate in length and for the RNA:DNA ratio was observed 28 d after that exposure ceased. The EROD induction doubled after the 96 h exposure, and a significant increase in GST activities was observed. A significant decrease in the specific growth rates, the otolith recent growth, the RNA:DNA ratio and the Fulton's K condition index were then observed in sea bass 26 d after the 96 h exposure to mechanically dispersed crude oil compared to the control. The present study shows that growth and condition indices can prove useful in assessing fish health status following an oil spill. Their complementary analysis with sensitive molecular biomarkers as EROD could improve the determination of oil spill impact on fish populations.

Growth and condition indices of juvenile turbot, Scophthalmus maximus, exposed to contaminated sediments: effects of metallic and organic compounds

Since sediments have the potential to form associations with several classes of pollutants, they have been recognized as a possible and significant source of contamination for the benthic environment. Flatfish maintain a close association with sediments for food and cover, and are therefore more likely to be exposed to contaminated sediments, especially in coastal areas (e.g. nursery grounds). The assessment of these potential biological effects involves the use of adapted biomonitoring tools. The main objective of this study was to assess and compare the response of several physiological biomarkers measured on juvenile turbot (Scophthalmus maximus) exposed to contaminated sediments. Sediments were collected from three stations in a harbour in northern France (Boulogne-sur-Mer), in an anthropogenic French estuary (the Seine), and in a reference site (exposed sandy beach of Wimereux). Unexposed lab-reared juvenile turbots were exposed to sediments for 7 and 21 days in laboratory conditions. Sediments were analysed for metals, PAH and PCB contamination. Several fish growth and condition indices were individually analysed in fish according to the chemical contaminant availability in sediment, the metal concentrations in gills and the estimation of PAH metabolites in their bile. Significant decreases in growth rates, morphometric index, RNA:DNA ratio and the lipid storage index, based on the ratio of the quantity of triacylglycerols on sterols (TAG:ST), were observed with increasing level of chemical contamination. This decrease in the fish's physiological status could be related to the significant increase of several metal concentrations in contaminated fish gills and the significant increase of PAH metabolites in bile. In a field situation, such a reduction in growth and energetic status of juvenile fish could dramatically decrease their over-winter survival in contaminated nursery grounds.

Are biochemical biomarker responses related to physiological performance of juvenile sea bass (Dicentrarchus labrax) and turbot (Scophthalmus maximus) caged in a polluted harbour?

Biomarker responses to toxic exposure have been used for decades to indicate stress in aquatic organisms, or the magnitude of environmental pollution. However, little has been done to compare the simultaneous responses of both biochemical and physiological biomarkers. The purpose of this study was twofold. Firstly to analyse the responses of several biochemical biomarkers measured on juvenile sea bass and turbot caged in a northern France harbour at a reference and contaminated stations. Several biotransformation parameters (Ethoxyresorufin-O-deethylase - EROD - and Glutathione S-transferase -GST) and an antioxidant enzyme (Catalase -CAT) were analysed. Secondly, to compare their responses to several growth and condition indices, measured on the same fish. In the contaminated station, EROD and GST activities were found to be significantly higher, and a decrease of CAT activity was observed for both species. For individual sea bass, biochemical biomarkers showed numerous significant correlations with growth and condition indices, such as the Fulton's K condition index, the RNA:DNA ratio and the lipid storage index. On the contrary, there were only a few significant correlations for turbot, suggesting a species-specific response. Our study indicates that the analysis of the simultaneous responses of both biochemical and physiological biomarkers can be useful for monitoring complex exposure and to assess habitat quality.

[Skin tanning and skin bleaching: ethnic addictions complying with the latest fad]

Sun is at the origin of life and is responsible for death as well. In the past decades cutaneous melanoma has affected more and more young adults. In the White population, sun exposures and sunbeds are pointed out as the main culprits responsible for addictive behaviour. Preventive measures to be taken aim at avoiding the effects of ultraviolet light addiction. Sunlight exposure particularly in moderation is indeed beneficial through vitamin D3 synthesis and improved psychological wellbeing. Hence, we are facing the dilemma between too much and too little ultraviolet light exposure.In the Black population, the reverse situation is prevalent. It concerns skin depigmentation which may turn out to be a caricature in some subjects.

An unusual presentation of a glomus tumour

Glomus tumours are benign, soft tissue tumours, usually of fingertips. Classically they present with severe pain, temperature sensitivity and localised tenderness. The diagnosis is often delayed due to sometimes non-specific symptoms and rarity of the disorder. While usually a clinical diagnosis, imaging may be necessary for diagnosis and localisation. We present a case of glomus tumour of the fingertip with an unusual history.

[Primary and secondary prevention of skin cancers]

The occurrence of the vast majority of skin cancers depends on the environment, in particular on exposure to ultraviolet light radiations. Several modalities of primary and secondary prevention are possible. The first modality relies on proper covering or remaining hidden under shadow. Textiles exhibit some photoprotective function the efficacy of which depends on their nature and diverse modulating factors. Sun protection cream, some food habits, the intake of non steroidal anti-inflammatory drugs, and that of specific food complements are supposed to be beneficial at various levels.

[How I treat....psoriasis comorbidities by adalimumab (Humira) anti-TNFalpha]

Psoriasis is primarily a chronic inflammatory skin disease burdened by some comorbidities including psoriatic alopecia, arthropathies, Crohn's disease, the metabolic syndrome and some cardiovascular involvement. During the past years, several biologicals corresponding to monoclonal antibodies were offered to treat psoriasis refractory to other potent conventional treatments. We review the effects of biologicals, in particular adalimumab (Humira), on psoriatic comorbidities.

[Hurting the "black, yellow, red" dogma of leg ulcers]

The medical history of a leg ulcer is spangled with episodes contributing to its chronicity before leading to possible healing. The complexity of the involved biological factors is undisputable. In order to simplify the management of these lesions, some doctors and nurses summarize the evolution of a leg ulcer in 3 phases according to the colour of the wound bed: black, yellow and red. The latter stage is commonly considered as a favourable condition for skin healing. We criticize such a concept by showing the anatomo-functional heterogeneity of the red wound bed.

Nudging hair shedding by antidandruff shampoos. A comparison of 1% ketoconazole, 1% piroctone olamine and 1% zinc pyrithione formulations

Hair shedding and hair thinning have been reported to be affected by dandruff and seborrhoeic dermatitis. The present study was conducted in 150 men presenting with telogen effluvium related to androgenic alopecia associated with dandruff. They were randomly allocated to three groups receiving each one of the three shampoos in the market containing either 1% ketoconazole (KTZ), 1% piroctone olamine (PTO) or 1% zinc pyrithione (ZPT). Shampoos had to be used 2-3 times a week for 6 months. Hair shedding during shampoo was evaluated semiquantitatively. Hair density on the vertex was evaluated on photographs using a Dermaphot. Trichograms were used for determining the anagen hair percentage and the mean proximal hair shaft diameter using computerized image analysis. The sebum excretion rate (SER, mug cm(-2) h(-1)) was also measured using a Sebumeter. The three treatments cleared pruritus and dandruff rapidly. At end point, hair density was unchanged, although hair shedding was decreased (KTZ: -17.3%, PTO: -16.5%, ZPT: -10.1%) and the anagen hair percentage was increased (KTZ: 4.9%, PTO: 7.9%, ZPT: 6.8%). The effect on the mean hair shaft diameter was contrasted between the three groups of volunteers (KTZ: 5.4%, PTO: 7.7%, ZPT: -2.2%). In conclusion, telogen effluvium was controlled by KTZ, PTO and ZPT shampoos at 1% concentration. In addition, KTZ and PTO increased the mean hair shaft thickness while discretely decreasing the sebum output at the skin surface.

[Case of the month. Acute generalized exanthematous pustulosis due to an iodinated contrast radiodiagnostic agent]

Iodinated contrast agents are frequently involved in delayed polymorphic adverse skin reactions. Acute generalized exanthematous pustulosis following administration of iodinated contrast agents is a rare but severe form of such reactions. The disease is characterized by the sudden occurrence of an erosive and pustular erythroderma with fever, leukocytosis and sometimes peripheral adenopathies and liver involvement. This condition is considered as an immunologic reaction, primarily involving T lymphocytes. The overall mortality reaches about 1%. Elucidating the differential diagnosis with other acute paroxysmal drug eruptions (toxic epidermal necrolysis, Steven-Johnson syndrome and drug hypersensitivity syndrome) is of paramount importance for establishing the adequate treatment of PEAG.

[Angiosarcoma in chronic lymphoedema: a case of Stewart-Treves syndrome]

The Stewart-Treves Syndrome is defined as an angiosarcoma (very aggressive malignant tumor originating from endothelial cells) appearing in a specific clinical setting. This tumor develops in patients suffering from chronic lymphedema of the upper limb following mastectomy and axillary lymph node dissection for breast cancer. The diagnosis relies on medical history, clinical examination and a histological assesment (biopsy or resection). This syndrome represents a rare clinical entity. Unfortunately, the prognosis is poor. A large surgical resection is the treatment of choice if the patient is a candidate for a surgical resection with a curative intent Radiotherapy is sometimes used as a palliative local treatment. Chemotherapy is only used in more advanced cases, not curable by surgery alone.

Chronophysiologie circadienne du cuir chevelu

Biological rhythms are numerous and vary according to periodicity and amplitude. Variations over the course of a day, particularly circadian rhythms have been reported in the skin of the face and forearms. However, little information is available about daily biorhythms of the scalp. The aim of the present study was to explore the chronophysiology of the scalp. We report a series of diurnal rhythms in 8 Caucasian men using the plexogram method at 4-h intervals over a 5-day period. Statistically significant biorhythms were found for the colour, hydration, barrier function and pH of the skin, and for the sebum excretion as well. The early afternoon was the time of maximum increase in redness, hydration, pH and sebum output, combined with decreased skin barrier function. The amplitude of some of these biorhythms was so discrete that their clinical relevance remained uncertain even when they appeared statistically significant. In view of the apparent synchronization between them, it is likely that a central oscillator exerts a major influence. However, only rare subjects exhibited biorhythms for all the considered physiological parameters. Hence, peripheral reactivity and/or environmental synchronizers also play an important role to define the good and bad respondors to the potential biorhythms of each individual parameter.

[How I treat....A stoutness-associated intertrigo]

Intertrigo is a common inflammatory disorder of various origins. It can represent a single skin manifestation or be part of a disorder possibly exhibiting specific manifestations on other parts of the body. Hence, intertrigo may represent a sign of a peculiar disease. It may also result from physicochemical aggressions of the skin following occlusion of the large skinfolds particularly in case of stoutness. In this intance, a treatment similar to that of diaper dermatitis can be offered. A paste enriched or not with miconazole nitrate is indicated to prevent or treat most presentations of intertrigo.

[How I explore...cheilitis]

A cheilitis is an inflammatory disease confined to the lips. Several origins are recognized. Their nature is often different in children and adults. Some are spongiotic due to irritation or allergic reaction. Other lesions are keratotic and can evolve to leucoplasia and epidermoid carcinoma.

[How I treat...diaper dermatitis]

Diaper dermatitis is the most frequent skin disorder of the newborn. Several clinical types are distinguished. The most frequent type results from increased fragility of the newborn buttock skin when covered by diapers. According to the mechanisms involved and the severity of the dermatitis, one can distinguish the intertrigo of the chubby baby, and the so-called "W", "Y" and "red panties" types of diaper dermatitis. When the effects of occlusion are not controlled by adequate absorption by the diapers maceration of the stratum corneum occurs. As a result, degradation of the skin barrier function takes place. In addition, the value of the coefficient of friction of the skin increases with epidermal weakening to rubbing. In addition, fecal enzymes alter urines and skin. Judicious hygiene measures and a correct choice of care and diapers are mandatory. Cutaneous colonisation by microorganisms, in particular the yeasts Candida spp, is the main complication. Adequate preventive and curative measures can combat diaper dermatitis with confidence. A miconazole paste allows to improve the tribological properties of the interface between diapers and the skin. It also corrects the degradation of the skin barrier function, reduces inflammation and abates the impact of Candida spp. in the pathogenesis of the skin disorder.

[How I treat...topical treatment of plaque type psoriasis by the combination of calcipotriol and betamethasone dipropionate]

The combination of calcipotriol and betamethasone dipropionate in a single topical formulation is a recent advance in treatment of plaque type psoriasis. Studies rooted on evidence-based medicine have been recently published. We report a synthesis and a critical analysis, critical analysis of these investigations, and translate their data with a view to apply them in daily practice.

[The calcipotriol-betamethasone dipropionate association]

The topical treatment of psoriasis benefits from the alternate use of dermocorticosteroids and vitamin D3 analogues. A new galenic formulation allows to combine them in a single application. Dovobet (LEO Pharma) ointment is the association of calcipotriol 50 microg/g with betamethasone dipoprionate 0.5 mg/g. This formulation boosts the therapeutic activity of calcipotriol. It also decreases the irritative inflammatory reaction due to calcipotriol without increasing the atrophogenic risk of the dermocorticoid.

[Cutaneous photoprotection]

Physical or chemical photoprotection is mandatory in order to prevent some of the negative effects of ultraviolet light exposure.

[Genophotodermatoses]

Genophotodermatoses can result from a defect in melanin synthesis, a defect in DNA repair or a congenital photosensibility.

[Light therapy]

Some cutaneous disorders can be treated by light under specific modalities. Balneotherapy, UVA phototherapy, PUVAtherapy, TL 01 phototherapy, extracorporeal photochemotherapy and external photodynamic therapy are representatives of this group of treatment modalities.

[Clinical case of the month. Atypical mycobacteria and mesotherapy]

Cutaneous infections due to atypical mycobacteria are varied. Their prevalence appears on the rise. The contamination comes from the environment following a breaking, even minimal, of the cutaneous barrier. Mesotherapy, particularly when performed using a mechanical device, is a well recognized iatrogenic origin of this type of microorganism inoculation

[Laser and pulsed light treatments]

Numerous types of lasers can exert different and specific effects in the skin. Devices delivering high intensity of pulsed light can exert similar effect.

[Artificial sources of light]

The artificial light sources are numerous. They emit a more or less delimited spectrum of wavelengths. Ultraviolet light dosimetry allows to control the amount of delivered energy.