Plasma Exosomal microRNA Profile Reveals miRNA 148a-3p Downregulation in the Mucosal-Dominant Variant of Pemphigus Vulgaris

The mucosal-dominant variant of pemphigus vulgaris (MPV) is an autoimmune disease characterized by oral mucosal blistering and circulating pathogenic IgG antibodies against desmoglein 3 (Dsg3), resulting in life-threatening bullae and erosion formation. Recently, microRNAs (miRNAs) have emerged as promising players in the diagnosis and prognosis of several pathological states. For the first time, we have identified a different expression profile of miRNAs isolated from plasma-derived exosomes (P-EVs) of MPV patients positive for antibodies against Dsg3 (Dsg3-positive) compared to healthy controls. Moreover, a dysregulated miRNA profile was confirmed in MPV tissue biopsies. In particular, a strong downregulation of the miR-148a-3p expression level in P-EVs of MPV patients compared to healthy controls was demonstrated. Bioinformatics prediction analysis identifies metalloproteinase-7 (MMP7) as a potential miR-148a-3p target. An in vitro acantholysis model revealed that the miR-148a-3p expression level was dramatically downregulated after treatment with Dsg3 autoantibodies, with a concomitant increase in MMP7 expression. The increased expression of MMP7 leads to the disruption of intercellular and/or extracellular matrix adhesion in an in vitro cellular model of MPV, with subsequent cell dissociation. Overexpression of miR-148a-3p prevented cell dissociation and regressed MMP7 upregulation. Our findings suggest a pivotal role of P-EV cargo in regulating molecular mechanisms involved in MPV pathogenesis and indicate them as potential MPV therapeutic targets.

Regeneration of dentin-pulp complex: Effect of calcium-based materials on hDPSCs differentiation and gene expression

OBJECTIVE

Dentin-pulp complex is object of interest in the regenerative endodontic field as well as the natural function of human dental pulp stem cells (hDPSCs) that may differentiate into specific cells able to repair and/or regenerate both hard and soft dental structures. The aim of the present study was to evaluate the capacity of hDPSCs to differentiate in odontoblastic-like cells by evaluating the expression of specific odontogenic-related genes and to prove the ability of treatment with calcium-based materials such as calcium carbonate (CaCO3), calcium hydroxide (Ca(OH)₂), and mineral trioxide aggregate (MTA).

METHODS

hDPSCs were obtained and isolated from a third molar of a young patient. Odontogenic-related gene expression was assessed unti1 28 days of culture as well as alkaline phosphatase activity (ALP). hDPSCs were cultured in odontoblastic-induction medium used as control, and in presence of different concentrations of CaCO_3, Ca(OH)₂, and MTA.

RESULTS

The results demonstrated an upregulation in odontoblastic cell-related genes, in particular of the early differentiation marker known as matrix extracellular phosphoglycoprotein (MEPE), as well as increased ALP activity and the presence of calcium deposits, mainly by stimulation with calcium derivatives. In this regard, treatment of pulp tissue with CaCO₃, Ca(OH)₂ and even better with MTA seemed to be effective for dentinogenesis.

SIGNIFICANCE

The ease of isolation of hDPSCs from discarded or extracted teeth offers a promising source of autologous cells that may be applied for regenerative purpose in combination with selected bioactive materials. However, further investigations should be conducted to confirm the obtained results.

Polylactic Acid/Poly(vinylpyrrolidone) Co-Electrospun Fibrous Membrane as a Tunable Quercetin Delivery Platform for Diabetic Wounds

Diabetic wound infections (DWI) represent one of the most costly and disruptive complications in diabetic mellitus. The hyperglycemic state induces a persistent inflammation with immunological and biochemical impairments that promotes delayed wound healing processes and wound infection that often results in extended hospitalization and limb amputations. Currently, the available therapeutic options for the management of DWI are excruciating and expensive. Hence, it is essential to develop and improve DWI-specific therapies able to intervene on multiple fronts. Quercetin (QUE) exhibits excellent anti-inflammatory, antioxidant, antimicrobial and wound healing properties, which makes it a promising molecule for the management of diabetic wounds. In the present study, Poly-lactic acid/poly(vinylpyrrolidone) (PP) co-electrospun fibers loaded with QUE were developed. The results demonstrated a bimodal diameter distribution with contact angle starting from 120°/127° and go to 0° in less than 5 s indicating the hydrophilic nature of fabricated samples. The release QUE kinetics, analyzed in simulated wound fluid (SWF), revealed a strong initial burst release, followed by a constant and continuous QUE release. Moreover, QUE-loaded membranes present excellent antibiofilm and anti-inflammatory capacity and significantly reduce the gene expression of M1 markers tumor necrosis factor (TNF)-α, and IL-1β in differentiated macrophages. In conclusion, the results suggested that the prepared mats loaded with QUE could be a hopeful drug-delivery system for the effective treatment of diabetic wound infections.

Antimicrobial and Antibiofilm Activity of Curcumin-Loaded Electrospun Nanofibers for the Prevention of the Biofilm-Associated Infections

Curcumin extracted from the rhizome of Curcuma Longa has been used in therapeutic preparations for centuries in different parts of the world. However, its bioactivity is limited by chemical instability, water insolubility, low bioavailability, and extensive metabolism. In this study, the coaxial electrospinning technique was used to produce both poly (ε-caprolactone) (PCL)-curcumin and core-shell nanofibers composed of PCL and curcumin in the core and poly (lactic acid) (PLA) in the shell. Morphology and physical properties, as well as the release of curcumin were studied and compared with neat PCL, showing the formation of randomly oriented, defect-free cylindrical fibers with a narrow distribution of the dimensions. The antibacterial and antibiofilm potential, including the capacity to interfere with the quorum-sensing mechanism, was evaluated on Pseudomonas aeruginosa PAO1, and Streptococcus mutans, two opportunistic pathogenic bacteria frequently associated with infections. The reported results demonstrated the ability of the Curcumin-loading membranes to inhibit both PAO1 and S. mutans biofilm growth and activity, thus representing a promising solution for the prevention of biofilm-associated infections. Moreover, the high biocompatibility and the ability to control the oxidative stress of damaged tissue, make the synthesized membranes useful as scaffolds in tissue engineering regeneration, helping to accelerate the healing process.

pH-Responsive Resveratrol-Loaded Electrospun Membranes for the Prevention of Implant-Associated Infections

To date, the implant-associated infections represent a worldwide challenge for the recently reported bacterial drug resistance that can lead to the inefficacy or low efficacy of conventional antibiotic therapies. Plant polyphenolic compounds, including resveratrol (RSV), are increasingly gaining consensus as valid and effective alternatives to antibiotics limiting antibiotic resistance. In this study, electrospun polylactic acid (PLA) membranes loaded with different concentrations of RSV are synthesized and characterized in their chemical, morphological, and release features. The obtained data show that the RSV release rate from the PLA-membranes is remarkably higher in acidic conditions than at neutral pH. In addition, a change in pH from neutral to slightly acidic triggers a significant increase in the RSV release. This behavior indicates that the PLA-RSV membranes can act as drug reservoir when the environmental pH is neutral, starting to release the bioactive molecules when the pH decreases, as in presence of oral bacterial infection. Indeed, our results demonstrate that PLA-RSV2 displays a significant antibacterial and antibiofilm activity against two bacterial strains, Pseudomonas aeruginosa PAO1, and Streptococcus mutans, responsible for both acute and chronic infections in humans, thus representing a promising solution for the prevention of the implant-associated infections.

Cationic Polymer Nanoparticles-Mediated Delivery of miR-124 Impairs Tumorigenicity of Prostate Cancer Cells

MicroRNAs (miRNAs) play a pivotal role in regulating the expression of genes involved in tumor development, invasion, and metastasis. In particular, microRNA-124 (miR-124) modulates the expression of carnitine palmitoyltransferase 1A (CPT1A) at the post-transcriptional level, impairing the ability of androgen-independent prostate cancer (PC3) cells to completely metabolize lipid substrates. However, the clinical translation of miRNAs requires the development of effective and safe delivery systems able to protect nucleic acids from degradation. Herein, biodegradable polyethyleneimine-functionalized polyhydroxybutyrate nanoparticles (PHB-PEI NPs) were prepared by aminolysis and used as cationic non-viral vectors to complex and deliver miR-124 in PC3 cells. Notably, the PHB-PEI NPs/miRNA complex effectively protected miR-124 from RNAse degradation, resulting in a 30% increase in delivery efficiency in PC3 cells compared to a commercial transfection agent (Lipofectamine RNAiMAX). Furthermore, the NPs-delivered miR-124 successfully impaired hallmarks of tumorigenicity, such as cell proliferation, motility, and colony formation, through CPT1A modulation. These results demonstrate that the use of PHB-PEI NPs represents a suitable and convenient strategy to develop novel nanomaterials with excellent biocompatibility and high transfection efficiency for cancer therapy.

Meldonium improves Huntington's disease mitochondrial dysfunction by restoring peroxisome proliferator-activated receptor γ coactivator 1α expression

Mitochondrial dysfunction seems to play a fundamental role in the pathogenesis of neurodegeneration in Huntington's disease (HD). We assessed possible neuroprotective actions of meldonium, a small molecule affecting mitochondrial fuel metabolism, in in vitro and in vivo HD models. We found that meldonium was able to prevent cytotoxicity induced by serum deprivation, to reduce the accumulation of mutated huntingtin (mHtt) aggregates, and to upregulate the expression of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) in mHTT-expressing cells. The PGC-1α increase was accompanied by the increment of mitochondrial mass and by the rebalancing of mitochondrial dynamics with a promotion of the mitochondrial fusion. Meldonium-induced PGC-1α significantly alleviated motor dysfunction and prolonged the survival of a transgenic HD Drosophila model in which mHtt expression in the nervous system led to progressive motor performance deficits. Our study strongly suggests that PGC-1α, as a master coregulator of mitochondrial biogenesis, energy homeostasis, and antioxidant defense, is a potential therapeutic target in HD.

The carnitine system and cancer metabolic plasticity

Metabolic flexibility describes the ability of cells to respond or adapt its metabolism to support and enable rapid proliferation, continuous growth, and survival in hostile conditions. This dynamic character of the cellular metabolic network appears enhanced in cancer cells, in order to increase the adaptive phenotype and to maintain both viability and uncontrolled proliferation. Cancer cells can reprogram their metabolism to satisfy the energy as well as the biosynthetic intermediate request and to preserve their integrity from the harsh and hypoxic environment. Although several studies now recognize these reprogrammed activities as hallmarks of cancer, it remains unclear which are the pathways involved in regulating metabolic plasticity. Recent findings have suggested that carnitine system (CS) could be considered as a gridlock to finely trigger the metabolic flexibility of cancer cells. Indeed, the components of this system are involved in the bi-directional transport of acyl moieties from cytosol to mitochondria and vice versa, thus playing a fundamental role in tuning the switch between the glucose and fatty acid metabolism. Therefore, the CS regulation, at both enzymatic and epigenetic levels, plays a pivotal role in tumors, suggesting new druggable pathways for prevention and treatment of human cancer.

EML4-ALK translocation identification in RNA exosomal cargo (ExoALK) in NSCLC patients: a novel role for liquid biopsy

The introduction of druggable targets has significantly improved the outcomes of non-small cell lung cancer patients (NSCLC). EML4-ALK translocation represents 4–6% of the druggable alterations in NSCLC. With the approval of Crizotinib, first discovered drug for the EML4-ALK translocation, on first line treatment for patients with detected mutation meant a complete change on the treatment landscape. The current standard method for EML4-ALK identification is immunohistochemistry or FISH in a tumor biopsy. However, a big number of NSCLC patients have not tissue available for analysis and others are not suitable for biopsy due to their physical condition or the location of the tumor. Liquid biopsy seems the best alternative for identification in these patients that have no tissue available. Circulating free RNA has not been validated for the identification of this mutation. As a complementary tool, exosomes might represent a good tool for predictive biomarkers study, and due to their stability, they preserve the genetic material contained in them. Our group has described for the first time the translocation EML4-ALK in RNA isolated from exosomes derived from NSCLC patients using next generation sequencing.

Recent advances in “bioartificial polymeric materials” based nanovectors

This chapter analyzes the advantages of the use of bioartificial polymers as carriers and the main strategies used for their design. Despite the enormous progresses in this field, more studies are required for the fully evaluation of these nanovectors in complex organisms and for the characterization of the pharmacodynamic and pharmacokinetic of the loaded drugs. Moreover, progresses in polymer chemistry are introducing a wide range of functionalities in the bioartificial polymeric material (BPM) nanostructures leading to a second generation of bioartificial polymer therapeutics based on novel and heterogeneous architectures with higher molecular weight and predictable structures, in order to achieve greater multivalency and increased loading capacity. Therefore, research on bioartificial polymeric nanovectors is an “on-going” field capable of attracting medical interest.

Exosomes genetic cargo in lung cancer: a truly Pandora's box

Lung cancer is a highly lethal disease. Targeted therapies have been developed in last years, however survival rates are not improving due to the delay in the diagnosis, making biomarkers one of the most interesting fields of study in cancer. Liquid biopsy has raised as an alternative to tissue biopsy due to improvements in analytical techniques for circulating tumor cells (CTCs), cell free DNA and exosomes. Among all, exosomes have raised as one of the most promising tools to understand the tumor due to their stability in the blood and their similarity to the cells of origin. In the last years, different alterations have been described inside the exosomes derived from non-small cell lung cancer (NSCLC) cells mirroring the processes inside these tumoral cells, such as EGFR mutation, translocations or microRNA (miRNA) deregulation. All these studies have opened the window to a new world of possibilities in the study of tumor biomarkers.

c-Myc modulation: a key role in melanoma drug response

Understanding molecular mechanisms involved in melanoma resistance to drugs is a big challenge. Experimental evidences suggested a correlation between mutational status in B-RAF and melanoma cell susceptibility to drugs, such as paclitaxel, doxorubicin and temozolomide, which generate an accumulation of hydrogen peroxide (H2O2) in the cells. We investigated the survival phenotype and the protein level of c-myc, a B-RAF target molecule, in melanoma cells, carrying a different mutational status in B-RAF, upon paclitaxel, doxorubicin and H2O2 treatment. For the first time, we reported c-myc modulation is critical for melanoma drug response. It appeared drug-specific and post-transcriptionally driven through PP2A; in correlation, cell pre-treatment with okadaic acid (OA), a specific PP2A inhibitor, as well as PP2A silencing of melanoma cells, was able to increase melanoma cell drug-sensitivity and c-myc protein level. This is relevant for designing efficacious therapeutic strategies in melanoma.

Ran signaling in melanoma: implications for the development of alternative therapeutic strategies

We performed a comparative study between two human metastatic melanoma cell lines (A375 and 526), and melanocytes (FOM78) by gene expression profiling and pathway analysis, using Gene Set Enrichment Analysis (GSEA) and Ingenuity Pathway Analysis (IPA) software. Genes involved in Ran signaling were significantly over-represented (p ≤ 0.001) and up-regulated in melanoma cells. A melanoma-associated molecular pathway was identified, where Ran, Aurora Kinase A (AurkA) and TERT were up-regulated, while c-myc and PTEN were down-regulated. A consistent high Ran and AurkA gene expression was detected in about 48% and 53%, respectively, of 113 tissue samples from metastatic melanoma patients. AurkA down-regulation was observed in melanoma cells, by Ran knockdown, suggesting AurkA protein is a Ran downstream target. Furthermore, AurkA inhibition, by exposure of melanoma cells to MLN8054, a specific AurKA inhibitor, induced apoptosis in both melanoma cell lines and molecular alterations in the IPA-identified molecular pathway. These alterations differed between cell lines, with an up-regulation of c-myc protein level observed in 526 cells and a slight reduction seen in A375 cells. Moreover, Ran silencing did not affect the A375 invasive capability, while it was enhanced in 526 cells, suggesting that Ran knockdown, by AurkA down-regulation, resulted in a Ran-independent enhanced melanoma cell invasion. Finally, AurK A inhibition induced a PTEN up-regulation and its action was independent of B-RAF mutational status. These findings provide insights relevant for the development of novel therapeutic strategies as well as for a better understanding of mechanisms underlying therapy resistance in melanoma.

Atrial natriuretic peptide and vasopressin-presence in the ciliary body of eye in the pig (sus domesticus)

The aqueous humor is produced in the ciliary body, therefore in this study we investigated the Atrial natriuretic peptide (ANP) and vasopressin (VP)-presence in the ciliary body of the pig eye since these peptide are involved in the homeostasis of body fluids. The results show ANP-presence in the epithelial cells and in the endothelial cells of the blood vessels and VP-presence in the epithelial cells, in the endothelium of canal of Schelmm and in the muscle cells of the blood vessels. These peptides might regulate the synthesis and the composition of the aqueous humor and regulate the hydrodynamic flow and haemodynamic flow of the blood.

Validation of microarray data in human lymphoblasts shows a role of the ubiquitin-proteasome system and NF-kB in the pathogenesis of Down syndrome

BACKGROUND

Down syndrome (DS) is a complex disorder caused by the trisomy of either the entire, or a critical region of chromosome 21 (21q22.1-22.3). Despite representing the most common cause of mental retardation, the molecular bases of the syndrome are still largely unknown.

METHODS

To better understand the pathogenesis of DS, we analyzed the genome-wide transcription profiles of lymphoblastoid cell lines (LCLs) from six DS and six euploid individuals and investigated differential gene expression and pathway deregulation associated with trisomy 21. Connectivity map and PASS-assisted exploration were used to identify compounds whose molecular signatures counteracted those of DS lymphoblasts and to predict their therapeutic potential. An experimental validation in DS LCLs and fetal fibroblasts was performed for the most deregulated GO categories, i.e. the ubiquitin mediated proteolysis and the NF-kB cascade.

RESULTS

We show, for the first time, that the level of protein ubiquitination is reduced in human DS cell lines and that proteasome activity is increased in both basal conditions and oxidative microenvironment. We also provide the first evidence that NF-kB transcription levels, a paradigm of gene expression control by ubiquitin-mediated degradation, is impaired in DS due to reduced IkB-alfa ubiquitination, increased NF-kB inhibitor (IkB-alfa) and reduced p65 nuclear fraction. Finally, the DSCR1/DYRK1A/NFAT genes were analysed. In human DS LCLs, we confirmed the presence of increased protein levels of DSCR1 and DYRK1A, and showed that the levels of the transcription factor NFATc2 were decreased in DS along with a reduction of its nuclear translocation upon induction of calcium fluxes.

CONCLUSIONS

The present work offers new perspectives to better understand the pathogenesis of DS and suggests a rationale for innovative approaches to treat some pathological conditions associated to DS.

Presence of oxytocin, vasopressin and atrial natriuretic peptide and their modification in rat hypothalamic paraventricular nucleus during resistance training

Many studies have demonstrated the physiological effects of oxytocin (OT), atrial natriuretic peptide (ANP) and vasopressin (VP) in the homoeostasis of body fluids during physical exercise. However, a little information is available about the related immunohistochemical changes in hypothalamic magnocellular neurosecretory system during and after the training. The aim of the present work was to study the immunohistochemical changes in OT, ANP and VP levels in the hypothalamic paraventricular nucleus during and after resistance exercise protocol. Three groups of Wistar rats were trained by a rung ladder protocol for 15, 30 and 45 days, respectively; a fourth group was left to rest for 15 days after the training. Finally, four sedentary groups were used as controls. The results show that resistance training induces a significant reduction in the percentage of OT-positive neurons, compared with sedentary controls. In contrast, this protocol did not induce any change in VP levels, and ANP levels did not change significantly. However, VP increased after the resting period of 15 days. Our work shows that neurons of the paraventricular nucleus are involved in body fluid homoeostasis during and after resistance exercise. The functional significance of these changes in OT and VP levels, during and after the protocol, needs to be further investigated.

Indoor air quality at the Correr Museum, Venice, Italy

Two multidisciplinary field surveys, one in winter and the other in summer have monitored the indoor microclimate, air pollution, deposition and origin of the suspended particulate matter and microorganisms of the Correr Museum, Venice. In addition, this study was focused to identify the problems caused by the heating and air conditioning system (HAC) and the effects due to the presence of carpets. Heating and air conditioning systems (HACs), when chiefly designed for human welfare, are not suitable for conservation and can cause dangerous temperature and humidity fluctuations. Improvements at the Correr Museum have been achieved with the assistance of environmental monitoring. The carpet has a negative influence as it retains particles and bacteria which are resuspended each time people walk on it. The indoor/outdoor pollutants ratio is greater in the summertime, when doors and windows are more frequently open to allow for better ventilation, illustrating that this ratio is mainly governed by the free exchange of the air masses. The chemical composition, size and origin of the suspended particulate matter have been identified, as well as the bacteria potentially dangerous to the paintings. Some general suggestions for improving indoor air quality are reported in the conclusions.

The indoor environment of a modern museum building, the Sainsbury Centre for Visual Arts, Norwich, UK

A multi-disciplinary approach was used to investigate the indoor environment of a modern museum building, and its suitability for the conservation of the collection therein. Climate, gaseous and particulate pollution and the concentrations of bacteria were measured in summer and winter campaigns. While the environment overall was found to be an acceptable one, a number of drawbacks were highlighted, the most serious of these being the large temperature and humidity fluctuations that occurred in the summer.

Determination of organophosphorus pesticides in fruits by on-line size-exclusion chromatography-liquid chromatography-gas chromatography-flame photometric detection

The determination of organophosphorus pesticides in fruits by size-exclusion chromatography (SEC) on a polystyrene column coupled on-line to a gas chromatography (GC) system was unsatisfactory as a result of interfering peaks in GC. A liquid chromatography step on silica gel was therefore inserted between the SEC and GC steps to filter out polar by-products. Samples of fruit (apples, grapes and kiwi fruits) were extracted, then the extract filtered or centrifuged and injected into an automated on-line SEC-liquid chromatography-GC-flame photometric detection. Recoveries were about 95% and the detection limits about 1 ng/g.

[Therapy with bromocriptine and behavior of various hormones in psoriasis patients]

The activity of bromocriptin has been clinically tested on 18 patients suffering from psoriasis. The plasma levels of Human Growth Hormone (HGH), Human Adrenocorticotropic Hormone (ACTH), Thyroid Stimulating Hormone (TSH), Prolactin (PL), Aldosterone and Cortisol were investigated in these 18 patients along with 35 untreated psoriatic patients and 19 normal subjects. Bromocriptin was shown to be effective in 13 of our 18 psoriatic patients. Plasma levels of HGH, ACTH, and Aldosterone, measured in all 53 psoriatic patients, were found to be higher than normal in 11, 26 and 40 patients respectively (HGH and Aldosterone: p less than 0,005; ACTH: p less than 0,001).

[Cosmetic acne and a test of comedogenicity]

A comedogenic test was carried out on the internal ear canal of four adult, masculine, albino rabbits, using butter of cacao and linseed oil, both known to be present in various cosmetic products. Histologic observation after 14 days showed follicular hyperkeratosis conferming the validity of this test.

[Endothelial cell culture as a model for the study of wound healing]

Endothelial cells culture can be considered a reliable method for investigating about granulation tissue production in wound healing and for evaluating the pharmacological action of some chemicals on granulation tissue development. Endothelial cells have been obtained from human umbilical cords after trypsin treatment and their endothelial origin has been demonstrated by light microscopy, by immunofluorescence against factor VIII associated protein and by the platelet adhesion assay. The influence of fibronectin as substratum and of hyaluronic acid as soluble factor on adhesion and growth of endothelial cells has been investigated. Both these substances, but especially hyaluronate, determine a better attachment and an increase in the growth rate when compared with control cultures plated on plastic substratum and without hyaluronic acid in the culture medium.

[Differences in the culture of pigment cells from various sources]

In order to look for a new culture system suitable for investigating on melanocyte biology, in-vitro experiments have been carried out on pigmented basal cell carcinoma, pigmented seborrhoeic keratosis and melanocytic nevus. Melanocytes cultured from pigmented basal cell carcinoma and pigmented seborrheic keratosis are dendritic and DOPA positive. These cells can be considered similar to those of normal skin. Pigmented cells cultured from nevi are quite different. They are spindle-shaped and only to a little extent are DOPA positive. These findings suggest that nevus cells could be non mature melanocytes stopped at an intermediate stage of differentiation.

[Use of monoclonal antibody 225.28S in the study of nevus cells in culture]

The aim of this work is to identify and purify cultured nevus cells. We used for our study monoclonal antibody 225.28S. This antibody reacts with a surface antigen which is expressed by nevus cells and melanoma cells, but it does not react with normal melanocytes. We studied 10 dermic nevi and we observed that antigenic determinant survives in cultured nevus cells. These results allowed us to employ the method of panning for purify cultured nevus cells.

DNA-repair after UV-irradiation in skin fibroblasts from patients with actinic keratosis

Autoradiographic counting technique was utilized to measure the ultraviolet-induced unscheduled DNA synthesis of skin fibroblasts from 12 patients with chronic actinic keratosis and from 12 healthy donors of about the same age. In order to reveal a possible regional difference of DNA repair between the parts of the body ordinarily exposed and those parts unexposed to sunlight, two cell strains were used for each examined subject; one developed from the forehead skin and the other from the abdominal or axillary skin. Unscheduled DNA synthesis appeared depressed in actinic keratosis patients, as compared with controls. In all examined subjects however cell strains from exposed skin showed a DNA repair more active than cell strains from unexposed skin. These findings show that skin cancer may be promoted in actinic keratosis patients by a defect of DNA repair. The exalted DNA repair of chronically sun exposed skin is probably the consequence of a defensive process caused by enzymatic induction.

[Reconstructive surgery of the biliary tract]

Reconstructive surgery of the bile ways involves a great commitment owing to the technical difficulties, the diversity of the nature, site and extent of the alteration to be treated, and because of the particular anatomical structure of the formations which have to be operated. The conditions that can benefit most from this type of surgery are represented by preoperative lesions of the bile ways and particularly stenoses which but not only follow such lesions if they are not treated in time, but may also follow other processes of a benign nature such as calculosis, cholangitis, anomalies of the bile ways treated wrongly during previous cholecystectomy, and at times malignant processes. Reconstructive surgery in bile way surgery means direct re-establishment of the duct to enable bile to flow from the liver to the duodenum. It presupposes a number of local conditions, such as the circumscription of the condition so that the stenotic segment can be removed and long-lasting end-to-end anastomosis effected. When it is possible, this must be considered the ideal procedure since it offers anatomophysiological recovery of bile way function. Operations have also been performed using various vein, artery, appendix, fascia lata, etc. grafts and prostheses using foreign matter such as rubber, vitallium,dacron, etc. tubes but results have always been hazardous and debatable. Personal cases and techniques are reported.