Redox agents regulate ion channel activity in vacuoles from higher plant cells

The ability of redox agents to modulate certain characteristics of voltage- and calcium-activated channels has been recently investigated in a variety of animal cells. We report here the first evidence that redox agents regulate the activation of ion channels in the tonoplast of higher plants. Using the patch-clamp technique, we have demonstrated that, in tonoplasts from the leaves of the marine seagrass Posidonia oceanica and the root of the sugar beet, a variety of sulphydryl reducing agents, added at the cytoplasmic side of the vacuole, reversibly favoured the activation of the voltage-dependent slow vacuolar (SV) channel. Antioxidants, like dithiothreitol (DTT) and the reduced form of glutathione, gave a reversible increase of the voltage-activated current and faster kinetics of channel activation. Other reducing agents, such as ascorbic acid, also increased the SV currents, although to a lesser extent in comparison with DTT and glutathione, while the oxidising agent chloramine-T irreversibly abolished the activity of the channel. Single channel experiments demonstrated that DTT reversibly increased the open probability of the channel, leaving the conductance unaltered. The regulation of channel activation by glutathione may correlate ion transport with other crucial mechanisms that in plants control turgor regulation, response to oxidative stresses, detoxification and resistance to heavy metals.

Effects of cytoplasmic Mg2+ on slowly activating channels in isolated vacuoles of Beta vulgaris

The slow vacuolar (SV) channel can mediate a large part of the ionic current in plant tonoplasts, but its actual physiological role is still unclear. We demonstrate that in vacuoles from the taproots of sugar beet (Beta vulgaris L.), besides Ca2+, cytoplasmic Mg2+ also plays an important role in promoting the activation of the SV channel. An increase in Mg2+ concentration decreases the time constants of channel activation and deactivation, and determines a consistent shift, towards negative voltages, of the conductance characteristic; as an example, when the free concentration of Mg2+ was increased from the micromolar range up to 10 mM the activation shifted by about -60 mV. The experimental results obtained, which are based on a fast perfusion procedure allowing us to change the solution bathing the vacuole in a few milliseconds, suggest that magnesium-binding is a faster process than the voltage-activation gating of the channel, which constitutes the rate-limiting step controlling channel opening. Interestingly, the activation of the channel mediated by Mg2+ depends on the cooperative binding of at least three magnesium ions. We verified that cytoplasmic magnesium favours the activation of SV channels in the presence of nanomolar cytoplasmic calcium concentrations. A critical discussion on the Calcium Induced Calcium Release (CICR) mechanism proposed for the SV channel is presented.

Effectiveness of a new cosmetic treatment for melasma

BACKGROUND

Melasma treatment is difficult due to extended treatment periods, suboptimal adherence, inconsistent results, and frequent relapses. Kojic acid has been shown to be effective in reducing melasma severity and is now increasingly used in cosmetic treatments.

AIMS

The purpose of the present study was to evaluate the effectiveness of a new cosmetic treatment for melasma at 45 and 90 days.

METHODS

Multicenter prospective study across 20 dermatology clinics/ambulatories. One hundred patients with mild-to-moderate melasma were evaluated. The primary endpoints were changes in mean modified melasma area and severity index (mMASI) score and patient-reported satisfaction at 45 and 90 days.

RESULTS

The mean age of patients was 45.19 ± 11.5 years. Most patients were female and Caucasian. Patients presented mixed (65%), epidermal (26%), and dermal (4%) types of melasma. Triggering factors were hormonal contraception (33%), pregnancy (31%), and pharmacological treatment (11%); mean disease duration was 6.7 ± 6.8 years. Overall, a statistically significant decrease in mean mMASI scores was seen at 45 (2.19 ± 0.182 vs 3.29 ± 0.267, P < .0001) and 90 days (1.27 ± 0.128 vs 3.29 ± 0.267, P < .00001). The highest reduction in mMASI scores was observed in patients with dermal melasma. IGA scores showed a statistically significant improvement in pigmentation at 90 days (P < .00001).

CONCLUSION

The novel cosmetic treatment was associated with the improvement of melasma, as assessed by mMASI.

Continuum source and a focusing technique for the 80-500-a spectral range: improvements

The performance of a triggered vacuum spark source, emitting continuum radiation in the vacuum uv down to 80 A, has been improved by adding a capillary made of insulating material and increasing the capacity of the condenser. A focusing system consisting of a toroidal mirror has been used in conjunction with the source and a grazing incidence spectrograph in the 500-80-A spectral range. The results obtained indicate considerable gains (of the order of a factor of 200) with respect to previously used sources, allowing photographic recording of spectra with only one flash while maintaining good spectral resolution.

Topical prebiotics/postbiotics and PRURISCORE validation in atopic dermatitis. International study of 396 patients

Aim: To investigate the efficacy and tolerability of a cream (Rilastil Xerolact PB) containing a mixture of prebiotics and postbiotics, and to validate the PRURISCORE itch scale in the management of atopic dermatitis.Methods: The study is based on 396 subjects of both sexes in three age groups (i.e., infants, children, adults) suffering from mild/moderate Atopic Dermatitis, recruited from 8 European countries and followed for 3 months.Results: The product demonstrated good efficacy combined with good/very good tolerability in all age groups. In particular, SCORAD, PRURISCORE and IGA scores decreased significantly over the course of the study. The PRURISCORE was preferred to VAS by the vast majority of patients.Conclusion: Even though the role of prebiotics and postbiotics was not formally demonstrated since these substances were part of a complex formulation, it can be reasonably stated that prebiotics and postbiotics have safety and standardization features that probiotics do not have. In addition they are authorized by regulatory authorities, whereas topical probiotics are not.

Probiotics and Prebiotics Orally Assumed as Disease Modifiers for Stable Mild Atopic Dermatitis: An Italian Real-Life, Multicenter, Retrospective, Observational Study

The role of the skin-gut axis in atopic dermatitis (AD) remains a subject of debate, limiting non-pharmacological interventions such as probiotics and prebiotics. To improve understanding of their potential as a monotherapy for stable mild cases, we conducted a real-life, multicenter, retrospective observational study in Italy. We administered three selected bacteria (Bifidobacterium animalis subsp. lactis BS01, Lactiplantibacillus plantarum LP14, and Lacticaseibacillus rhamnosus LR05) orally to patients with mild atopic dermatitis without a placebo control group, following up for 12 weeks. Clinical assessments using the Scoring Atopic Dermatitis (SCORAD), Eczema Area and Severity Index (EASI), and Three-Item Severity (TIS) score were conducted on 144 enrolled patients (average age: 25.1 ± 17.6 years). Notably, both pruritus and AD-related lesions (erythema, edema/papules, excoriation) exhibited significant clinical and statistical improvement (p < 0.001) after 12 weeks of exclusive probiotic and prebiotic use. These preliminary results suggest a potential link between the skin-gut microbiome and support the rationale for using specific probiotics and prebiotics in mild AD, even for maintenance, to reduce flares and dysbiosis.

[Treatment of histamine-dependent allergic dermatoses with a 120-mg terfenadine tablet once a day]

Terfenadine, an anti-H1-selective antihistaminic drug has been used in an experimental clinical study. The effectiveness and tolerance of the compound in the treatment of pruritic dermatitis such as urticaria, atopic dermatitis and topical dermatitis, have been evaluated. Terfenadine, administered in 120 mg tablets in a single daily dose in 30 patients demonstrated a fully satisfactory therapeutic activity and reliability of use.

Effects of FCE20700, a new PGE2 derivative, on gastric acid secretion and cytoprotective processes in man

The pharmacodynamic effects of FCE20700, a new PGE2 derivative, have been investigated in 6 healthy volunteers given single intragastric (i.g.) and intraduodenal (i.d.) doses of 1 and 2 mg and placebo, according to a double-blind, within-subjects design. For 30-270 min following i.g. administration the effect of FCE20700 on peptone-stimulated gastric acid secretion (AS) was assessed by i.g. titration, and serum gastrin (G) levels were also determined. For the same period after i.d. dosing the effect of the compound on pentagastrin-stimulated AS and on mucoproteins and bicarbonate content in the gastric juice was measured. Blood pressure (BP), heart rate and possible side-effects were monitored. Following i.g. administration there was a moderate, dose-related, significant inhibition of AS; significant inhibition of G levels was observed only after the highest dose. After i.d. administration there was a very modest though dose-related and significant inhibition of AS; a brief maximal increase in mucoproteins and in bicarbonate levels was apparent after the 1 mg dose. After i.d. but not after i.g. administration of 2 mg there was a modest but significant decrease in BP. No side-effects of clinical relevance were reported. The results appear to suggest a major activity of FCE20700 on cytoprotection rather than in inhibiting gastric acid secretion. The observed change in BP may indicate that after i.d. administration there will be some systemic effects of FCE20700.

[1% econazole hair-shampoo in the treatment of pityriasis capitis; a comparative study versus zinc-pyrithione shampoo]

On the basis of the assumption that Pityrosporum ovale is an important pathogenic factor in the aetiology of Pityriasis simplex capitis (dandruff), the Authors intended to evaluate the efficacy and tolerability of econazole (1% hair-shampoo) in the treatment of this scalp disease. Dandruff could be considered a problem more from a cosmetic than from a medical point of view; for this reason a conventional anti-dandruff hair-shampoo containing zinc-pyrithione was selected as a control. In this open controlled study, seventy patients suffering from different forms of Pityriasis simplex capitis were enrolled at the 1th Dermatological Institute, University of Milan, and randomly assigned to the econazole and zinc-pyrithione treatment groups, respectively. At the end of the four-weeks treatment (two applications/week) a marked decrease in signs (scaling, seborrhea, erythema) and symptoms (burning, itching) was observed in both groups. Regarding the antifungal efficacy, econazole hair-shampoo was slightly better than control. General evaluation on tolerability and cosmetical patterns was favourable for both formulations.

Unusual features of pyoderma gangrenosum: two atypical cases

Two cases of pyoderma gangrenosum are described that are atypical in the appearance of their skin lesions and their association with intestinal diseases.