Acefylline activates filaggrin deimination by peptidylarginine deiminases in the upper epidermis.

BACKGROUND: Peptidylarginine deiminases (PADs) catalyze deimination (or citrullination), a calcium-dependent post-translational modification involved in several physiological processes and human diseases, such as rheumatoid arthritis and cancer. Deimination of filaggrin (FLG) by PAD1 and PAD3 during the last steps of keratinocyte differentiation is a crucial event for the epidermis function and homeostasis. This allows the complete degradation of FLG, leading to the production of free amino acids and their derivatives that are essential for epidermal photoprotection and moisturizing of the stratum corneum. OBJECTIVE: To increase the flux of this catabolic pathway, we searched for activators of PADs. METHODS: A large chemical library was screened first in silico and then by using an automated assay based on an indirect colorimetric measurement of recombinant human PAD activity. Potential activators were then confirmed using a recombinant human FLG as a substrate, and secondly after topical application at the surface of three-dimensional reconstructed human epidermis. RESULTS: The data obtained after the library screening pointed to xanthine derivatives as potential PAD activators. Among seven xanthine derivatives tested at 50-300µM, caffeine, theobromine and acefylline proved to be the most potent enhancers of in vitro deimination of FLG by PAD1 and PAD3. After topical application of a gel formulation containing 3% acefylline at the surface of reconstructed epidermis, immunoblotting analysis showed an increase in the total amount of deiminated proteins, and confocal microscopy showed an enhanced deimination in the stratum corneum. This demonstrated the activation of PADs in living cells. CONCLUSION: As a PAD activator, acefylline will be useful to study the role of deimination and could be proposed to increase or correct the hydration of the cornified layers of the epidermis.

Therapeutic efficiency of everolimus and lapatinib in xenograft model of human colorectal carcinoma with KRAS mutation.

KRAS mutation is a negative predictive prognostic factor during metastatic colorectal cancer treatment with antiepidermal growth factor receptor antibodies. For affected patients, new therapeutics must be explored. Our objective was to study efficacy of two drugs with different mechanisms of action, everolimus (mTOR inhibitor) and lapatinib (tyrosine kinase inhibitor), in a mouse xenograft model. We chose a model obtained after engraftment of a tumor originating from a human tumor collection. The patient was affected by a metastasis colorectal carcinoma resistant to cetuximab with KRAS mutation. From a previous study in mice, we know that everolimus is a P-glycoprotein (P-gp) substrate and that a lapatinib pretreatment increases significantly (2.6-fold) everolimus AUC by inhibiting its intestinal P-gp efflux. We hence tested the effect of these drugs alone or combined. Mice bearing the xenografts were divided in four groups: control, lapatinib, everolimus, and L/E group (L/E: 2 days of lapatinib 200 mg/kg and then 3 days of everolimus 1 mg/kg). Tumor volumes and treatment toxicities were evaluated. Sixteen days after treatment initiation, the group L/E was the first one in which tumor volume average was significantly lower than the one of control group (193 ± 90 vs. 395 ± 171 mm(3) ; P = 0.0025). After 4 weeks of treatment, inhibition of tumor growth in lapatinib, everolimus, and L/E groups reached, respectively, 49, 53, and 57%. Each drug showed significant antitumor activity. Only moderate hematologic toxicity signs were observed. These results lead to new perspectives for new oral drugs in metastatic KRAS-mutated colorectal cancer resistant to standard chemotherapy.

Disposable diapers biodegradation by the fungus Pleurotus ostreatus.

This research assesses the feasibility of degrading used disposable diapers, an important component (5-15% in weight) of urban solid waste in Mexico, by the activity of the fungus Pleurotus ostreatus, also known as oyster mushroom. Disposable diapers contain polyethylene, polypropylene and a super absorbent polymer. Nevertheless, its main component is cellulose, which degrades slowly. P. ostreatus has been utilized extensively to degrade cellulosic materials of agroindustrial sources, using in situ techniques. The practice has been extended to the commercial farming of the mushroom. This degradation capacity was assayed to reduce mass and volume of used disposable diapers. Pilot laboratory assays were performed to estimate the usefulness of the following variables on conditioning of used diapers before they act as substrate for P. ostreatus: (1) permanence vs removal of plastic cover; (2) shredding vs grinding; (3) addition of grape wastes to improve structure, nitrogen and trace elements content. Wheat straw was used as a positive control. After 68 days, decrease of the mass of diapers and productivity of fungus was measured. Weight and volume of degradable materials was reduced up to 90%. Cellulose content was diminished in 50% and lignine content in 47%. The highest efficiency for degradation of cellulosic materials corresponded to the substrates that showed highest biological efficiency, which varied from 0% to 34%. Harvested mushrooms had good appearance and protein content and were free of human disease pathogens. This research indicates that growing P. ostreatus on disposable diapers could be a good alternative for two current problems: reduction of urban solid waste and availability of high protein food sources.

Recombinant interleukin-2 pre-treatment increases anti-tumor response to paclitaxel by affecting lung P-glycoprotein expression on the Lewis lung carcinoma.

The aim of the present study was to examine modifications of anti-tumor activity and toxicity of paclitaxel (PLX) when given p.o. after recombinant interleukin-2 (rIL-2) to Lewis lung carcinoma-bearing mice. PLX was given orally to mice at the dose of 15 mg/kg on day 8 and 30 mg/kg on day 15, either alone or after 16.5 microg of rIL-2 given i.p. twice a day either 1 or 3 days before. The anti-tumor activity was higher and PLX hematological toxicity not increased if orally administered PLX was given after a 3-day rIL-2 pre-treatment rather than if given alone. Lung metastasis was significantly lower and s.c. tumors were smaller in the PLX+rIL-2 group than in the PLX or rIL-2 or non-treated groups. In addition, a decrease in lung P-glycoprotein expression (investigated by Western blot analysis) was observed 1 h after the last administration of rIL-2 on day 7.

Pharmacokinetics and neutrophil toxicity of paclitaxel orally administered in mice with recombinant interleukin-2.

PURPOSE: Intrinsic P-glycoprotein (P-gp) expression in the gut limits paclitaxel uptake and, thus, its bioavailability when administered orally. Interleukin-2 has been reported to be a P-gp modulator in vitro and in vivo in mice. In the work described here, the effects of interleukin-2 pretreatment on pharmacokinetics and toxicity of paclitaxel orally administered were investigated. METHODS: For the pharmacokinetic study, 96 mice were allocated to two groups receiving either 10 mg/kg of paclitaxel by the oral route alone or 16.5 microg of human recombinant interleukin-2 (rIL2) by the intraperitoneal route twice daily for 3 days and then paclitaxel. Pharmacokinetic profiles were analysed first by the Bailer method, and then using a compartmental approach. For the toxicity study, 90 Swiss mice were allocated to three groups receiving paclitaxel (10 mg/kg orally), rIL2 alone (16.5 microg i.p. twice daily for 3 days, control group), or both treatments. Haematological parameters were measured and the three groups were compared using the Bailer method. A Bonferroni correction was applied to the test. RESULTS: A complex absorption of paclitaxel was revealed. The Bailer method showed that the mean area under the curve (AUC) values over 0-24 h were not significantly different in the two groups, despite a trend to reduced AUC in the pretreated group. The AUC over 0-0.5 h was significantly higher in the group pretreated with rIL2, but represented only a fraction of total exposure. These results were confirmed by the compartmental analysis. The elimination rate constant remained the same across both groups. rIL2 thus increased paclitaxel absorption for the 15 min following oral intake of the drug but did not enhance the overall exposure. CONCLUSION: We found that a 3-day pretreatment with rIL2 had some in vivo inhibitory effects on P-gp activity for a short period after oral dosing of paclitaxel. Those results encourage further investigation of the effect of rIL2 on the overall exposure of paclitaxel. On the other hand, it seems that the joint administration of the two drugs did not increase the risk of myelosuppression, which might be worth knowing to treat advanced cancers.

Effects of electromagnetic fields on the immune systems of occupationally exposed humans and mice.

The authors examined immunological disorders in 6 individuals who had been exposed occupationally to environmental electromagnetic fields. Comparable effects on mice exposed in a similar environment were also investigated. The human subjects had worked 8 hr/day for 5 yr in a laboratory located above electrical transformers and high-tension cables, and in which there were low-frequency electromagnetic fields of 0.2-6.6 microtesla (microT). The 6 control subjects (matched for socioeconomic parameters, sex, and age) had worked away from the immediate vicinity of transformers and high-tension cables. The authors found statistically significantly lower total lymphocyte, CD4, and CD3 counts, and significantly increased natural killer (NK) cells, in exposed subjects vs. controls. Six months after exposure had ceased, total lymphocyte counts had increased, as had CD4, CD3, and CD19 counts (+13%, +28%, +22%, and +17%, respectively), and NK cell counts were decreased by 26% (not significant) in the same human subjects. In the second part of this study, 12 Swiss male mice housed in cages were exposed in the same room in which the human subjects had been exposed (i.e., 5-microT, 50-Hz magnetic field) for 109 days; 12 additional mice were used as unexposed controls. The total lymphocyte, leukocyte, polymorphonuclear neutrophil, CD4, and NK counts of the exposed mice at 109 days were significantly lower than those of controls. In addition, plasma glucose levels (at 30 days) and amylase activity (at 109 days) were significantly lower, whereas plasma sodium and chloride levels were significantly elevated at 109 days. Results from this study suggest that chronic exposure to a 0.2-6.6-microT magnetic field can lead to decreased immunological parameters (total lymphocytes and CD4 counts) in both humans and mice. The increase in some values once exposure was terminated suggests a causal relationship with exposure to electromagnetic fields, as do the changes in mice, particularly the changes in total lymphocyte and CD4 counts.

Marker rhythms of circadian system function: a study of patients with metastatic colorectal cancer and good performance status.

Cancer patients may exhibit normal or altered circadian rhythms in tumor and healthy tissues. Four rhythms known to reflect circadian clock function were studied in 18 patients with metastatic colorectal cancer and good performance status. Rest-activity was monitored by wrist actigraphy for 72 h before treatment, and its circadian rhythm was estimated by an autocorrelation coefficient at 24h and a dichotomy index that compared the activity level when in and out of bed. Blood samples (9-11 time points, 3-6 h apart) were drawn on day 1 and day 4 of the first course of chronochemotherapy (5-fluorouracil: 800 mg/m2/day; folinic acid: 300 mg/m2/day; oxaliplatin: 25 mg/m2/day). Group 24h rhythms were validated statistically for plasma concentrations of melatonin, 6-alpha-sulfatoxymelatonin, and cortisol and for lymphocyte counts. Significant individual 24h rhythms were displayed in melatonin by 15 patients, cortisol by seven patients, lymphocytes by five patients, and prominent circadian rhythms in activity were displayed by 10 patients; only one patient exhibited significant rhythms in all the variables. The results suggest the rhythms of melatonin, cortisol, lymphocytes, and rest/activity reflect different components of the circadian system, which may be altered differently during cancer processes. Such 24h rhythm alterations appeared to be independent of conventional clinical factors.

Diseño, construcción e instalación de un lisimetro

Investiga la contaminación por el lixiviado de relleno sanitario y la falta de seguridad en los cálculos para el diseño y construcción de los mismos. Señala la caracterización del biogás y de los lixiviados generados en los rellenos sanitarios y determina los parámetros nacionales para su diseño. Propone instalar tres prototipos o lisimetros con las mismas características de construcción y de relleno. Este trabajo describe el diseño, construcción e instalación del primer lisimetro