Influence of chitin nanofibrils ultrasonic treatment on structure and properties of chitosan-based composite materials.

The influence of ultrasonic treatment parameters of chitin nanofibrils aqueous suspension on structure, strength and deformation properties of chitosan-based composite films and fibers was investigated. Model calculations of ultrasound-induced cavitation parameters in the aqueous suspension of the chitin nanofibrils showed that an increase in the field power up to 630 W led to destruction of the cavity, to an increase in the temperature in the vicinity of cavitation area (up to 507 °C) and, as a consequence, to destruction of chitin glycoside ring (which is confirmed by the IR data). The results of light scattering, IR spectroscopy, and electron microscopy investigations indicated that the optimal duration of ultrasonic treatment of the chitin nanofibrils aqueous solution was 4-10 min (depending on oriented state of the scaffold). Tensile strength of the composites was 130 ± 11 MPa (films), 226 ± 4.8 MPa (fibers); deformation at break was 43 ± 7.5% (films), 10 ± 0.6% (fibers).

Influence of surface morphology of chitosan films modified by chitin nanofibrils on their biological properties.

The paper is devoted to the study of influence of chitin nanofibrils on the structure, surface morphology, mechanical properties, and electrical conductivity of chitosan-based composite films intended for use in biomedical technologies. It was demonstrated that the optimal concentration of chitin nanofibrils in the composite film is 5 wt.%. For the films of this composition, we observed orientation of structural elements on film surface, enhanced mechanical properties as well as an increase in both specific conductivity and proliferative activity of skin fibroblasts on film surface. These results are related to the appearance of oriented structure in nanocomposites and to self-organization of chitosan macromolecules on the surface of chitin nanofibrils. It was revealed that increase in surface energy and surface hydrophilicity did not facilitate effective adhesion, viability and proliferative activity of cells during cultivation on the surface of composite films.

New chitin complexes and their anti-aging activity from inside out.

BACKGROUND: Nutritional and topical antioxidants and immuno-modulant compounds play a key role in maintaining healthy skin. However, little is known about the combined effects antioxidant cosmeceuticals and nutricosmetics can have on the appearance of aging skin. OBJECTIVE: The clinical trial was designed to study the combined effects on skin hydration, superficial lipids, elasticity, peroxidation and global clinical appearance, of melatonin, Vit. E and Betaglucan (MEB) complexed with chitin nano-crystals administered both topically and orally. Clinical examinations were conducted by dermatologists. DESIGN: By a randomized placebo-controlled, 12 week multicenter study on 70 healthy subjects, affected with skin photo-aging, the anti-aging efficacy and tolerability of the combined activity of topical emulsion and oral hard capsules, containing MEB complexed with chitin nano-crystals (CN) was evaluated clinically and by biophysical non-invasive measurements at week 4,8 and 12. RESULTS: The effects of MEB intake resulted significantly higher (p<0.005) than placebo for all the parameters evaluated by biophysical and clinical measurements. The values resulted higher when the active ingredients MEB were complexed with CN, whether used topically, orally or a combination of both (p<0.05). The positive results, observed since week 4, were accompanied by no side-effects throughout the entire study. CONCLUSION: The combined topical and oral use of MEB was associated with reduced wrinkling, better skin appearance and general overall wellness. When MEB were complexed with CN, the obtained results were statistically more positive (p<0.05) for all the biophysical and clinical parameters considered.

Topical clindamycin 1% vs. linoleic acid-rich phosphatidylcholine and nicotinamide 4% in the treatment of acne: a multicentre-randomized trial.

It has been shown that topical linoleic acid rich-phosphatidylcholine seems to be effective in normalization of follicular hyperkeratinization, whereas nicotinamide has an interesting anti-inflammatory effect. However, little is known about their combined effect on acne. A multicentre, double-blind, 12-week randomized vehicle and parallel-active control study was conducted by clinical and biophysical non-invasive measurements to evaluate the efficacy, tolerability and safety of a 4% nicotinamide-phospholipidic (N-PHCL) emulsion vs. 1% topical clindamycin phosphate applied once daily. Four percentage N-PHCL cosmetic treatment resulted slightly superior to topical clindamycin with all the parameters studied for its better compliance and the global clinical improvement.

Transforming nanostructured chitin from crustacean waste into beneficial health products: a must for our society.

Chitin, obtained principally from crustacean waste, is a sugar-like polymer that is available at low cost. It has been shown to be bio- and ecocompatible, and has a very low level of toxicity. Recently, it has become possible to industrially produce pure chitin crystals, named "chitin nanofibrils" (CN) for their needle-like shape and nanostructured average size (240 × 5 × 7 nm). Due to their specific chemical and physical characteristics, CN may have a range of industrial applications, from its use in biomedical products and biomimetic cosmetics, to biotextiles and health foods. At present, world offshore disposal of this natural waste material is around 250 billion tons per year. It is an underutilized resource and has the potential to supply a wide range of useful products if suitably recycled, thus contributing to sustainable growth and a greener economy.

Beneficial long-term effects of combined oral/topical antioxidant treatment with the carotenoids lutein and zeaxanthin on human skin: a double-blind, placebo-controlled study.

BACKGROUND: The skin is exposed to numerous environmental assaults that can lead to premature aging. Of these agents, perhaps none is more ubiquitous than the ultraviolet (UV) wavelengths of sunlight. The primary immediate defense against environmental skin damage is the antioxidant capacity of the skin. However, this defense system can be compromised by moderate exposure to UV light. Therefore, bolstering the antioxidant defense system of the skin is a potentially important strategy for reducing environmentally induced skin damage. AIM OF THE STUDY: This clinical trial was designed to study the efficacy of lutein and zeaxanthin, two potentially important antioxidants found naturally in the skin, upon five skin physiology parameters (surface lipids, hydration, photoprotective activity, skin elasticity and skin lipid peroxidation - malondialdehyde) of human subjects. These xanthophyllic carotenoids were administered either orally, topically, or in combination (both oral and topical routes). RESULTS: The results obtained indicate that the combined oral and topical administration of lutein and zeaxanthin provides the highest degree of antioxidant protection. However, oral and topical administration of these antioxidants individually also provides significant activity in the skin. In addition, oral administration of lutein may provide better protection than that afforded by topical application of this antioxidant when measured by changes in lipid peroxidation and photoprotective activity in the skin following UV light irradiation.

Role of topical and nutritional supplement to modify the oxidative stress.

BACKGROUND: Evidence suggests that signs of skin ageing such as wrinkling, ragging and actinic lentigines, may be connected to cumulative oxidative damage incurred throughout our lifetimes. To counteract this oxidative injury, skin is equipped with a network on enzymatic and non-enzymatic antioxidant systems, such as tocopherols, ascorbate polyphenols. All these compounds administered topically by cosmetics or by oral route by diet supplements, have been shown to exert an antioxidant/protective effect in skin or skin cells. OBJECTIVE: The object of this study was to evaluate both in vitro and in vivo the activity performed by different topical antioxidants and nutritional supplements. METHODS: A randomized double-blind placebo-controlled study was carried out for 8 weeks on 30 dry-skinned elderly volunteers, women aged between 48 and 59 years, with moderate xerosis and photoageing. Surface skin lipids, skin hydration and MDA determination were topically detected by 3C System. ROS was evaluated on the blood serum and on IL-3 stimulated human leukocytes by ROS Meter System at 505 nm. All the subjects applied twice a day for 2 months a nanocolloidal gel and/or take a diet supplement by oral route at the quantity of two capsules per day. All the formulations used were antioxidant-enriched (ascorbic acid, tocopherol, alpha-lipoic acid, melatonin, emblica). RESULTS: Oxidative stress and consequently lipids peroxidation decreased from 30 to 40% (P < 0.005) in blood serum of all the subjects treated with antioxidant compounds topically and by oral route. Both free radicals recovered in blood serum and on skin (in vivo) and ROS induced by irradiation of leucocytes with UVB light (in vitro), appear sensibly lower in subjects antioxidant-treated. CONCLUSIONS: From the obtained data, it seems possible to conclude that all the compounds used play interesting role as topical and systemic photoprotectants, thanks to their interesting antioxidant property. Moreover, the antioxidant treatment seems to be a promising therapeutic approach also in reducing the oxidative stress of people affected by photoaging.

Biochemical studies of a natural antioxidant isolated from rosemary and its application in cosmetic dermatology.

Oxidative damage to DNA, RNA, proteins and cell membranes occurs when the cellular concentration of reactive oxygen species exceeds the capacity of the cell to eliminate them. Aerobic prokaryotic and eukaryotic organisms have developed a set of cell defense systems to mitigate the damaging effects of reactive oxygen species. Epithelial surfaces contain antioxidants that could be expected to provide a defence against environmental stress caused by reactive oxygen and nitrogen species. Skin, which has a highly differentiated and complex structure, is particularly vulnerable to free radical damage because of its contact with oxygen and with other environmental stimuli. Fruit and vegetables contain several classes of compounds that when ingested can potentially contribute to endogenous modulation of antioxidant defences. The purpose of this study was to investigate the effectiveness of a natural extract derived from rosemary to protect free radical-induced skin damage. We provide evidence that an alcoholic extract of rosemary leaves, Rosm1, is endowed with strong antioxidant activity and, as evaluated by both in vitro and in vivo systems, is capable of inhibiting oxidative alterations to skin surface lipids. The present study provides a preclinical perspective on the interface between the biochemical properties of a natural extract isolated from rosemary leaves, a better understanding of the endogenous antioxidant potential of skin and the real validity of natural antioxidant biotechnology in antiaging skin management.

New data on skin photoprotection.

Absorbed ultraviolet (UV) radiation is responsible for photochemical degradation of the skin. Erythema is the most apparent result of the sunburn reaction, but the most serious results are photoaging and photocarcinogenesis, largely mediated by reactive oxygen species (ROS). To prevent these light-induced reactions, effective protection against both UVB and UVA radiations are essential. The aim of this study was to evaluate the protective efficacy against both UVB and UVA rays of three sunscreen preparations (two creams and one lotion), evaluating also their water resistance. For this purpose SPF (Sun Protection Factor) and UVA protection were tested, respectively, on 40 and 20 pre-selected volunteers (male and female, < 22-years-old with skin types I, II and III) by the Colipa test method and the Mark et al. methodology. A wash-off test was also conducted to determine the resistance to water. Results obtained showed that the three formulations studied underline interesting SPF values from about 20-30 with an excellent correlation between visual and colorimetric results obtained (P < 0.05). The controlled decrease in effectiveness of only 20% after 10 min washing proved that the vehicle is also an important factor in determining the protective efficacy. From the obtained data, the studied formulations seem to have an high SPF and UVA protection efficacy together with a good water resistance. According to several other studies, it is possible to confirm therefore that the regular use of these sunscreens may certainly reduce the harmful effect caused by long-term exposure to UVB and UVA radiation.

An ex vivo biochemical model to study the antioxidant clinical properties of cosmetic products in human antiaging skin care.

It is generally accepted that lipid peroxides play an important role in the pathogenesis of free radical-induced cellular injury and that endogenous thiols are vital in cellular defense against oxidative stress. The purpose of this study was to investigate in cultured human skin fibroblasts the effect of oxidative stress on the synthesis of heat shock protein (HSP70) and on the sulfhydryl group content in the absence and presence of alpha-tocopherol as an antioxidant compound. The interesting observation emerging from this study was a marked increase in malonaldehyde and fluorescent peroxide levels associated with a significant thiol depletion and induction of HSP70 stress proteins observed in primary cultures of normal human skin fibroblasts subjected to heat shock or incubated with hydrogen peroxide. These changes were significantly reduced in the presence of alpha-tocopherol. Our findings suggest a correlation between the mechanisms of oxidative stress, antioxidants and HSP70 induction, which can be assessed to evaluate either the perturbation of skin oxidant/antioxidant balance or the protection afforded by antioxidant test compounds.

Extraction and analysis of cosmetic active ingredients from an anti-cellulitis transdermal delivery system by high-performance liquid chromatography.

A new transdermal delivery system that controls cellulitis is evaluated using reversed-phase high-performance liquid chromatography coupled with photodiode array detection. An extraction procedure and the validation of the analytical method to assay the active excipients from the Centella asiatica plant (asiaticoside, madacessic acid, and asiatic acid) are described. Excellent results ae obtained in terms of linearity, accuracy, and specificity of the analytical method.

Oxidative stress and antioxidants at skin biosurface: a novel antioxidant from lemon oil capable of inhibiting oxidative damage to the skin.

Atmospheric pollutants are an important source of oxidative and nitrosative stress both to terrestrial plants and to animals. Skin, which has a highly differentiated and certainly complex organizational structure, is particularly vulnerable to free radical damage because of its contact with oxygen and with other environmental stimuli. Fruit and vegetables contain several classes of compounds that when ingested can potentially contribute to antioxidant defenses. In the present study we employed a novel gas chromatographic method to assess the antioxidant properties of a natural compound isolated from lemon oil, which we have called Lem1. We provide experimental evidence that Lem1 is endowed with a strong antioxidant activity and that it is capable of inhibiting free radical-mediated reactions, as evaluated in vitro and in vivo. The present study extends our previous findings and demonstrates that topical application of Lem1 in healthy volunteers significantly increases the antioxidative potential of skin biosurface, thus highlighting the effectiveness of a natural antioxidant biotechnology in the antiaging management of skin.

[Delivery after previous cesarean section. Experience with 173 patients]. / Il parto nella precesarizzata. Esperienza relativa a 173 pazienti.

We have taken into consideration the obstetric outcome in 173 women, with prior cesarean section, who were delivered in our hospital between june 1988 and january 1991. This group of patients represented 5.3% of our obstetric population. Overall 64 patients (37%) achieved vaginal delivery and 109 (63%) underwent an iterative cesarean section. Considering the 76 patients (44%) admitted to trial of labour, 64 (84.2%) achieved vaginal delivery and 12 (15.8%) were delivered with iterative cesarean section. No maternal or neonatal complications occurred, even though the silent dehiscence of the uterine scar, found during cesarean section, seems to occur four times (12%) more frequently than that reported in recent literature. It follows that vaginal delivery after prior cesarean section is, in our experience, lacking in risks, and we think that such management may be widely adopted. In 1986 iterative cesarean section represented 35% of cesarean section indications, in 1990 this rate was reduced to 23.7% by the introduction of a policy to allow women to undergo trial of labour.

[Gelatin-cystine, keratogenesis and structure of the hair]. / Gelatina-cistina, cheratogenesi e struttura pilifera.

It is known how noticeable modifications may be induced in the high sulphur content proteins of wool, by enrichment of the diet of sheep with cysteine or sulphur amino acids. It is also well known how the oral ingestion of gelatin significantly increases hair diameter and the degree of hardness of finger and toe nails. To the end of verifying the possible stimulating selective action performed by cystine and gelatin in the keratinization processes of the hairy structures, it was controlled: amino acids content in hair of normal rat after oral ingestion of a controlled quantity of gelatin-cystine added in the diet. The same experiments have been carried out on rats in which the condition of sufference of the hair was induced by means of a biotin-free diet. From the obtained data it seems that gelatin-cystine, added in the diet of normal or suffering rats, helps to modify the cysteine content of the sulphur-rich hair proteins (+ 50% abt.). The diet supplement bring about a considerable increasing of CYS (+ 35%) with a decreasing of GLY (- 15%).