[Features phase transfer catalytic glycosylation of aromatic hydroxy acids]

The catalytic phase transfer reactions of per acetylated alpha-D-glucosaminyl chloride with isomeric hydroxybenzoic, 1-hydroxy-2-naphthoic acids in solid potassium carbonate--acetonitrile were studied. It was found that the composition and yields of reaction products are determined by the nature of the source ofcarboxylic acids, lipophilic phase transfer catalyst, temperature. For the first time found that the O-beta-glycosyl esters of ortho-hydroxyaromatic acids in the presence of potassium carbonate can anomerizovatsya in 1,2-cis derivatives. The structure of the synthesized compounds proved 1H NMR spectroscopy. In in vivo experiments it was established that glycosyl esters of salicylic acid and per acetylated 2-carboxy phenylglucosaminide exhibit analgesic activity similar to aspirin.

An evaluation of the benefits of a topical treatment in the improvement of photodamaged hands with age spots, freckles, and/or discolorations

BACKGROUND

Photoaging of the hands is common due to frequent exposure to environmental factors.

OBJECTIVE

To evaluate the efficacy of a topically applied cream formulated with an alpha-hydroxy acid, depigmenting agents, and antioxidants to improve the appearance of characteristics associated with photodamaged hands.

METHODS

This was a single-site, open-label study of a proprietary topical treatment (Vivité Vibrance Décolleté, Allergan, Inc.) in adult female subjects with moderate-to-severe photoaging of the hands. The treatment was administered to the hands twice daily over an 8-week period. Treatment efficacy was assessed at baseline and weeks 4 and 8 using the Investigator Global Assessment (IGA) score based on the percentage coverage and color depth of photodamaged areas. The severity of age spots, freckles, and hand skin discoloration were also assessed; digital and ultraviolet photography of the hands was performed. Subject-reported assessments of treatment efficacy were evaluated using a questionnaire administered at week 8. Statistical significance was defined with an α set at P≤.05.

RESULTS

Thirty-five subjects were enrolled with a mean age of 55.6 years; 33 subjects completed the study. The IGA of the appearance of hand photodamage improved from a mean (standard deviation) score of 5.0 (0.8) at baseline to 3.1 (1.5) and 2.6 (1.3) at weeks 4 and 8, respectively (1=mild; 9=severe). Based on expert-grader evaluation, subjects demonstrated statistically significant improvements from baseline in IGA at weeks 4 and 8 in age spots and freckling at weeks 4 and 8, (P<.0003) and in skin discolorations at week 8 (P<.05). The majority of subjects reported that they perceived improvements in each of the 9 parameters associated with skin appearance. No adverse events were reported.

CONCLUSIONS

The appearance of age-related hand pigmentation characteristics were significantly improved at 4 and 8 weeks of treatment. Subjects reported post-treatment improvements in other characteristics associated with healthy skin.

A double-blind, randomized clinical trial of 20% alpha/poly hydroxy acid cream to reduce scaling of lesions associated with moderate, chronic plaque psoriasis

BACKGROUND

Salicylic acid is a topical keratolytic agent used to reduce scaling and hyperkeratosis associated with psoriasis vulgaris. However, its use is limited due to potential systemic toxicity. Hydroxyacids also modulate keratinization and desquamation. Therefore, they may serve a beneficial role in the treatment of hyperkeratotic conditions. To date, there are no clinical studies in the literature regarding the efficacy of hydroxyacids for psoriasis treatment.

PURPOSE

To evaluate the therapeutic efficacy of topical 20% alpha-hydroxy/polyhydroxy acid versus standard salicylic acid to reduce scaling in patients with moderate, chronic psoriasis.

METHODS

Twenty-five subjects with moderate, chronic psoriasis were enrolled in a 2-week, double-blind, left-right, randomized, bilateral comparison clinical trial to compare the efficacy of 20% alpha-hydroxy/polyhydroxy acid emollient versus 6% salicylic acid cream and 24 were randomized/completed. Clinical evaluations to assess the severity of psoriasis and scaling were performed using a 6-point scale prior to treatment, as well as following 1 and 2 weeks of therapy.

RESULTS

Twenty-four participants completed the study. Both 20% alpha-hydroxy/polyhydroxy acid emollient and 6% salicylic acid cream were efficacious in reducing scale of psoriatic lesions. The topical 20% alpha-hydroxy/polyhydroxyacid reduced scaling at a faster rate; however, following 2 weeks of treatment the efficacy of both products were relatively the same.

CONCLUSION

20% alpha-hydroxy/polyhydroxyacid is as efficacious as salicylic acid in regards to the de-scaling of psoriatic plaques. Additionally, 20% alpha-hydroxy/polyhydroxyacid cream may yield quicker results and less toxicity than salicylic acid.

Local therapy as basic anti-aging prevention

Skin, the largest organ of the body, is the organ in which changes associated with aging are most visible. Intrinsic (chronologic) skin aging is characterized by atrophy of the skin with loss of elasticity and slowed metabolic activity. With superposition of environmental damage, particularly exposure to ultraviolet radiation (photodamage) on the intrinsic aging, the process results, at least initially, in hypertrophic repair response with thickened epidermis and increased melanogenesis. Even more striking changes occur in the dermis, i.e., massive elastosis (deposition of abnormal elastic fibers), collagen degeneration, and twisted, dilated microvasculature. Regular use of a sunscreen alone appears to allow for some repair as well as protection from further photodamage. Local anti-aging therapy has been shown to partially reverse the clinical and histologic changes induced by the combination of sunlight exposure and chronologic aging. Histologic changes in the epidermis and dermis noted after 12 months suggest repair of photodamage by reconstitution of rete pegs, repair of keratinocyte ultrastructural damage, more even distribution of melanocytes and melanin pigment, deposition of new papillary dermal collagen, and improvements in vasculature. Hyperkeratinization is normalized, while epidermal thickness and dermal glycosaminoglycan content are increased. Briefly, many of the unwanted changes can be improved by topical therapy.

The role of cosmeceuticals in antiaging therapy

As baby boomers get older, they have shown an increasing interest in maintaining a youthful appearance. As a result, there has been a corresponding increase in topical antiaging formulations, which are commonly referred to as cosmeceuticals. These products come with a seemingly limitless number of key active ingredients and claims of reducing the signs of aging and/or maintaining a youthful appearance. This paper reviews the more common cosmeceutical ingredients.

Systemic administration of diazoxide induces delayed preconditioning against transient focal cerebral ischemia in rats

Diazoxide is the prototypical opener of mitochondrial ATP-sensitive potassium channels (mitoK(ATP)) and protects neurons in vivo and in vitro against chemical and anoxic stresses. While we have previously shown that diazoxide administration induces acute preconditioning against transient cerebral ischemia in rats, the potential for delayed preconditioning of diazoxide has not been examined. The purpose of this study was to determine whether diazoxide promotes delayed preconditioning following 90 min of middle cerebral artery occlusion (MCAO) in male Wistar rats. Diazoxide (10 mg/kg) or vehicle was injected intraperitoneally 24 h before MCAO. Infarct volumes were measured 72 h after reperfusion. In animals anesthetized with halothane, treatment with diazoxide exhibited a 35% reduction (48.3+/-3.0% to 31.3+/-4.8%) and 18% reduction (35.1+/-2.2% to 28.9+/-2.1%) in cortical and subcortical infarct volumes, respectively. Administration of the mitoK(ATP) blocker 5-hydroxydecanoate attenuated this beneficial effect. In contrast, diazoxide did not induce delayed preconditioning in isoflurane-anesthetized rats. These findings support the concept that diazoxide produces delayed preconditioning via mitoK(ATP) activation but that physiological status can affect induction of preconditioning.

Managing acne vulgaris effectively

The management of acne is a gratifying experience. Available treatments are effective, relatively nontoxic and generally safe. However, there is no quick fix. Antibiotics, hormone therapies and topical therapies are maintenance treatments. Isotretinoin can induce remission, as can some of the newer physical modalities of lights, lasers and radiofrequency devices. Effective management of acne often requires using a combination of treatments that act on different parts of the pathogenic process of acne development.

Effects of alpha-hydroxy acids on the human skin of Japanese subjects: the rationale for chemical peeling

Alpha-hydroxy acid (AHA) agents, such as glycolic acid and lactic acid, have been used as therapeutic agents for more than a quarter of a century. Recently, they have been used as agents to rejuvenate photo-aged skin. It is believed that these AHA agents induce the epidermis to remodel and accelerate desquamation, thus exerting their therapeutic effects. In this study, we investigated the histological differences in skin treated with glycolic, lactic, citric and acetic acids once daily for 6 weeks. The melanin pigments in the basal layer were less prominent in the glycolic and lactic acid-treated skin than in the citric and acetic acid-treated skin. The melanin deposits in the horny layers were equal for all AHA. However, the melanin deposits in the squamous layers were less prominent in the glycolic and lactic acid-treated skins than in the citric and acetic acid-treated skins; this was analogous to observations of the basal layers. Collagen I and procollagen I were increased after treatment with glycolic, lactic and citric acid in the upper dermis, but were not increased with acetic acid treatment. However, the staining of the epidermis and dermis for matrix metalloproteinase-1 (MMP-1) after treatment was not significantly different among the agents. Our data suggest that longer treatment intervals with glycolic and lactic acid can cause improvements in both the epidermal and dermal components and support the usefulness of AHA for rejuvenating photo-damaged skin.

Inhibition of cardiac contractility by 5-hydroxydecanoate and tetraphenylphosphonium ion: a possible role of mitoKATP in response to inotropic stress

This study investigates the role of the mitochondrial ATP-sensitive K+ channel (mitoKATP) in response to positive inotropic stress. In Langendorff-perfused rat hearts, inotropy was induced by increasing perfusate calcium to 4 mM, by adding 80 microM ouabain or 0.25 microM dobutamine. Each of these treatments resulted in a sustained increase in rate-pressure product (RPP) of approximately 60%. Inhibition of mitoKATP by perfusion of 5-hydroxydecanoate (5-HD) or tetraphenylphosphonium before induction of inotropic stress resulted in a marked attenuation of RPP. Inhibition of mitoKATP after induction of stress caused the inability of the heart to maintain a high-work state. In human atrial fibers, the increase in contractility induced by dobutamine was inhibited 60% by 5-HD. In permeabilized fibers from the Langendorff-perfused rat hearts, inhibition of mitoKATP resulted, in all cases, in an alteration of adenine nucleotide compartmentation, as reflected by a 60% decrease in the half-saturation constant for ADP [K1/2 (ADP)]. We conclude that opening of cardiac mitoKATP is essential for an appropriate response to positive inotropic stress and propose that its involvement proceeds through the prevention of stress-induced decrease in mitochondrial matrix volume. These results indicate a physiological role for mitoKATP in inotropy and, by extension, in heart failure.

Activation of mitochondrial ATP-sensitive potassium channels improves rotenone-related motor and neurochemical alterations in rats

Our previous studies revealed that activation of mitochondrial ATP-sensitive potassium channels exerted protective effects on rotenone-treated rats and cultured cells. The aim of the present study is to examine the potential therapeutic effects of iptakalim, an ATP-sensitive potassium-channel opener, and diazoxide, a selective mitochondrial ATP-sensitive potassium-channel opener, on Parkinsonian symptoms in rats induced by rotenone. Rats were treated with rotenone (2.5 mg/kg s.c.) daily for 4 wk. This treatment caused a depletion of dopamine in the striatum and substantia nigra. Behaviourally, rotenone-infused rats exhibit Parkinsonian symptoms. Catalepsy was estimated by a 9-cm bar test. Treatment with L-dopa (10 mg/kg.d p.o.), iptakalim (0.75, 1.5, 3.0 mg/kg.d p.o.) and diazoxide (3.0 mg/kg.d p.o.) for 2 wk improved behavioural dysfunction and elevated dopamine contents in the striatum and substantia nigra of rotenone-treated rats. Studies also found that iptakalim and diazoxide could reduce the enzymic activities and mRNA levels of inducible nitric oxide synthase elicited by chronic administration of rotenone. All neurorestorative effects by both iptakalim and diazoxide were abolished by 5-hydroxydecanoate, a selective mitochondrial ATP-sensitive potassium-channel blocker. Collectively, the data suggested that mitochondrial ATP-sensitive potassium channels play a key role in improving both Parkinsonian symptoms and neurochemistry alterations of rotenone model rats, and selective activation of mitochondrial ATP-sensitive potassium channels may provide a new therapeutic strategy for treatment of early Parkinson's disease.

A role of opening of mitochondrial ATP-sensitive potassium channels in the infarct size-limiting effect of ischemic preconditioning via activation of protein kinase C in the canine heart

The opening of mitochondrial ATP-sensitive K+ (mitoK(ATP)) channels triggers or mediates the infarct size (IS)-limiting effect of ischemic preconditioning (IP). Because ecto-5'-nucleotidase related to IP is activated by PKC, we tested whether the opening of mitoK(ATP) channels activates PKC and contributes to either activation of ecto-5'-nucleotidase or IS-limiting effect. In dogs, IP procedure decreased IS and activated ecto-5'-nucleotidase, both of which were mimicked by transient exposure to either cromakalim or diazoxide, and these effects were blunted by either GF109203X (a PKC inhibitor) or 5-hydroxydecanoate (a mitoK(ATP) channel blocker), but not by HMR-1098 (a surface sarcolenmal K(ATP) channel blocker). Either cromakalim or diazoxide activated both PKC and ecto-5'-nucleotidase, which was blunted by either GF109203X or 5-hydroxydecanoate, but not by HMR-1098. We concluded that the opening of mitoK(ATP) channels contributes to either activation of ecto-5'-nucleotidase or the infarct size-limiting effect via activation of PKC in canine hearts.

Intrahippocampal administration of the branched-chain α-hydroxy acids accumulating in maple syrup urine disease compromises rat performance in aversive and non-aversive behavioral tasks

Maple syrup urine disease (MSUD) is an inherited metabolic disease predominantly characterized by neurological dysfunction. Although a variable degree of psychomotor/delay/mental retardation is found in a considerable number of MSUD patients, the mechanisms underlying the neuropathology of this disorder are yet not defined. The present study investigated the effect of acute intrahippocampal administration of the branched-chain alpha-hydroxy acids (BCHA) accumulating in MSUD on rat behavior in non-aversive (open field) and aversive (inhibitory avoidance) tasks. Cannulated 60-day-old male Wistar rats received bilateral intrahippocampal injection of alpha-hydroxyisocaproic acid (HIC, 1.5 micromol), alpha-hydroxyisovaleric acid (HIV, 2.5 micromol), alpha-hydroxy-beta-methyl-n-valeric acid (HMV, 1.5 micromol), or NaCl (2.5 micromol)(controls) immediately after or 10 min before training. Testing session was performed 24 h later. Administration of the hydroxy acids immediately after training caused no effect on the cognitive performance of the rats. In contrast, HIV and HMV administered 10 min before training provoked a habituation deficit in the open field task. Motor activity, assessed by crossing responses, was the same for the groups infused with BCHA and NaCl. The effect of MK-801, succinate, creatine, and the antioxidants ascorbic acid plus alpha-tocopherol on the behavioral alterations provoked by HIV in the open field task revealed that only the energetic substrates (succinate and creatine) prevented these effects, reflecting a possible compromise of brain energy production by HIV. We also observed that rats pretreated with HIC, HIV, or HMV did not increase their latency in the testing session in the step-down inhibitory avoidance task, revealing an impairment of retrieval (memory retention or acquisition) in this task. Furthermore, no differences between controls and rats receiving BCHA were detected in the latency to leave the platform in the training test, suggesting similar motor activity of all groups. The data indicate that the alpha-hydroxy acids accumulating in MSUD impair cognition and may be implicated in the neuropathology and psychomotor delay/mental retardation observed in the affected patients.

Sevoflurane depolarizes pre-synaptic mitochondria in the central nervous system

BACKGROUND

Volatile anaesthetics protect the heart from ischaemic injury by activating mitochondrial signalling pathways. The aim of this study was to test whether sevoflurane, which is increasingly used in neuroanaesthesia, affects mitochondrial function in the central nervous system by altering the mitochondrial membrane potential (DeltaPsi(m)).

METHODS

In order to correlate free cytosolic Ca(2+) ([Ca(2+)](i)) and DeltaPsi(m), rat neural presynaptic terminals (synaptosomes) were loaded with the fluorescent probes fura-2 and JC-1. During sevoflurane exposure, 4-aminopyridine (4-AP) 500 micro M to induce pre-synaptic membrane depolarization or carbonylcyanide-p-(trifluoromethoxy)-phenylhydrazone (FCCP) 1 micro M to induce maximum mitochondrial depolarization was added. In order to block mitochondrial ATP-regulated K(+)-channels (mitoK(ATP)), the antagonist 5-hydroxydecanoate (5-HD) 500 micro M was added.

RESULTS

In Ca(2+)-containing medium, both sevoflurane 1 and 2 MAC gradually decreased the normalized JC-1 ratio from 0.96 +/- 0.01 in control to 0.92 +/- 0.01 and 0.89 +/- 0.01, representing a depolarization of DeltaPsi(m) (n = 9, P < 0.05). Sevoflurane 2 MAC increased [Ca(2+)](i). In Ca(2+)-depleted medium, sevoflurane 1 and 2 MAC depolarized DeltaPsi(m), while [Ca(2+)](i) remained unaltered. Sevoflurane 2 MAC attenuated the 4-AP-induced depolarization of DeltaPsi(m). When mitoK(ATP) was blocked, the sevoflurane-induced depolarization of DeltaPsi(m) was attenuated, but not blocked. The depolarizing effect of sevoflurane on DeltaPsi(m) compared with FCCP was calculated to 13.2 +/- 1.3% in Ca(2+)-containing and 15.1 +/- 1.2% in Ca(2+)-depleted medium (n = 7).

CONCLUSIONS

Sevoflurane depolarizes DeltaPsi(m) in rat synaptosomes, and the effect is not dependent on Ca(2+)-influx to the cytosol. Opening of mitoK(ATP) is partly responsible for the depolarizing effect of sevoflurane.

The use of polyhydroxy acids (PHAs) in photoaged skin

The beneficial effects of alpha-hydroxyacids (AHAs) on skin were discovered by Drs. Van Scott and Yu in the early 1970s, including exfoliation, skin smoothing, and antiaging effects. A new generation of AHAs, called polyhydroxy acids (PHAs), was discovered that provide similar effects as AHAs but do not cause the sensory irritation responses that can limit the use of classical AHAs. PHAs have been found to be compatible with clinically sensitive skin, including rosacea and atopic dermatitis, and can be used after cosmetic procedures. PHAs provide additional humectant and moisturization properties compared with AHAs and can enhance stratum corneum barrier function, therefore increasing the skin's resistance to chemical challenge. Most PHAs also possess antioxidant properties. PHAs such as gluconolactone or lactobionic acid may be used in combination with other products, ingredients, or procedures such as laser and microdermabrasion to provide additional benefits to therapy or to enhance the therapeutic effect. Several studies were conducted in support of this, and methods and results are discussed. In summary, PHA-containing products were used in combination with retinoic acid in treating adult facial acne and were found to be well tolerated. PHAs plus retinyl acetate (pro-vitamin A) in a cream base exhibited significant antiaging skin benefits such as skin smoothing and plumping. PHAs plus hydroquinone showed excellent improvement in antiaging and skin lightening parameters. Finally, PHA-containing products were shown to be compatible with African American, Caucasian, and Hispanic/Asian skin and provided significant improvements in photoaging in these populations.

Cardiomyocyte mitochondrial KATP channels participate in the antiarrhythmic and antiinfarct effects of KATP activators during ischemia and reperfusion in an intact anesthetized rabbit model

Recent evidence suggests that the mitochondrial K(ATP) channels may be involved as a subcellular mediator in cardioprotection afforded by ischemic and pharmacological preconditioning by K(ATP) activators. The present study investigated the effects of administration of non-hypotensive doses of ATP-sensitive K(+) channel (K(ATP)) openers, nicorandil (NIC) and pinacidil (PIN), and specific blockers of mitochondrial (5-hydroxydecanoate) and sarcolemmal (1-[5-[2-(5-chloro-o-anisamido)ethyl]-2-methoxyphenyl]sulfonyl-3-methyl-thiourea, HMR 1883) K(ATP) channels prior to and during coronary occlusion and post-ischemic reperfusion on survival rate, ischemia- and reperfusion-induced arrhythmias and myocardial infarct size in anesthetized rabbits. In Group I, myocardial ischemia-induced arrhythmias were provoked by tightening a ligature over the left main coronary artery for 30 min. In Group II, arrhythmias were induced by reperfusion following a 20 min ligation of the same artery. Both in Group I and Group II, early iv administration of NIC (0.47 mg/kg), PIN (0.1 mg/kg), HMR 1883 (3 mg/kg)/NIC and HMR 1883/PIN just prior to and during ischemia increased survival rate (75%, 86%, 75% and 75%, respectively, vs. 55% in the control in Group I; 75%, 75%, 75% and 67%, respectively, vs. 50% in the control in Group II), significantly decreased the incidence and severity of life-threatening arrhythmias and significantly decreased myocardial infarct size. However, late iv administration of NIC or PIN just prior to reperfusion did not increase survival rate nor confer any antiarrhythmic or cardioprotective effects. The antiarrhythmic and cardioprotective effects were abolished by pretreating rabbits with 5-hydroxy-decanoate (5 mg/kg, iv bolus). In the present study, higher levels of malondialdehyde and lower levels of reduced glutathione and superoxide dismutase in necrotic zone of myocardium in all subgroups in Group II suggest little anti-free radical property of NIC and PIN. Therefore, it may be assumed that mitochondrial K(ATP) channel opening leads to mitochondrial generation and release of ROS providing for IPC and antiarrhythmic activity. The mitochondrial rather than sarcolemmal K(ATP) channel may represent a potential site of cardioprotection and antiarrhythmic activity.

Mitochondrial K ATP channel activation is important in the antiarrhythmic and cardioprotective effects of non-hypotensive doses of nicorandil and cromakalim during ischemia/reperfusion: a study in an intact anesthetized rabbit model

The roles of cardiomyocyte sarcolemmal ATP-sensitive K(+) (K(ATP)) and mitochondrial K(ATP) channels in the cardioprotection and antiarrhythmic activity induced by K(ATP) channel openers remain obscure, though the mitochondrial K(ATP) channels have been proposed to be involved as a subcellular mediator in cardioprotection afforded by ischemic preconditioning. In the present study, we investigated the effects of administration of non-hypotensive doses of ATP-sensitive K(+) channel (K(ATP)) openers (nicorandil and cromakalim), a specific mitochondrial K(ATP) channel blocker (5-hydroxydecanoate (5-HD)) and a specific sarcolemmal K(ATP) channel blocker (HMR 1883; (1-[5-[2-(5-chloro-o-anisamido)ethyl]-2-methoxyphenyl]sulfonyl-3-methylthiourea) prior to and during coronary occlusion as well as prior to and during post-ischemic reperfusion on survival rate, ischemia-induced and reperfusion-induced arrhythmias and myocardial infarct size in anesthetized albino rabbits. The thorax was opened in the left 4th intercostal space and after pericardiotomy the heart was exposed. In Group I (n=80), occlusion of the left main coronary artery and hence, myocardial ischemia-induced arrhythmias were achieved by tightening a previously placed loose silk ligature for 30min. In Group II (n=184), arrhythmias were induced by reperfusion following a 20 min ligation of the left main coronary artery. Both in Groups I and II, early intravenous infusion of nicorandil (100 micro g/kg bolus+10 micro g/kg/min), cromakalim (0.2 micro g/kg/min), HMR 1883 (3mg/kg)/nicorandil and HMR 1883 (3mg/kg)/cromakalim just prior to and during ischemia increased survival rate (75%, 67%, 86% and 75% versus 60% in the control subgroup in Group I; 75%, 75%, 75% and 67% versus 50% in the control subgroup in Group II), significantly decreased the incidence and severity of life-threatening arrhythmias and significantly decreased myocardial infarct size. However, late intravenous administration of nicorandil or cromakalim at the onset and during reperfusion did neither increase survival rate nor confer any antiarrhythmic or cardioprotective effects. The antiarrhythmic and cardioprotective effects of both nicorandil and cromakalim were abolished by pretreating the rabbits with 5-HD (5mg/kg, i.v. bolus), a selective mitochondrial K(ATP) channel blocker but not by HMR 1883 (3mg/kg). In the present study, higher levels of malondialdehyde (MDA) and lower levels of reduced glutathione (GSH) and superoxide dismutase (SOD) in necrotic zone of myocardium in all the 16 subgroups in Group II suggest little anti-free radical property of nicorandil and cromakalim.We, therefore, conclude that intervention by intravenous administration of nicorandil and cromakalim (through the selective activation of mitochondrial K(ATP) channels), increased survival rate and exhibited antiarrhythmic and cardioprotective effects during coronary occlusion and reperfusion in anesthetized rabbits when administered prior to and during coronary occlusion. The mitochondrial K(ATP) channel may be a potential site of cardioprotection and antiarrhythmic activity.

Topical glycolic acid enhances photodamage by ultraviolet light

BACKGROUND

Alpha-hydroxy acids (AHAs) are widely used as ingredients in cosmetics. Several studies suggest that AHAs can increase the sensitivity of skin to ultraviolet (UV) light.

PURPOSE

This study was performed in order to determine whether short-term dermal treatment with glycolic acid, a representative AHA, can enhance the damaging effects of UV light. The duration of the effect of AHAs on the sensitivity of skin to UV light was also examined.

METHODS

The backs of 29 Caucasian subjects were treated, once daily, 6 days per week with either 10% glycolic acid (pH 3.5) or placebo in a randomized double-blinded study. At the end of 4 weeks, sites within each treated area were exposed to 1.5 MED of UV light, determined on previously untreated skin. Specimens were obtained for enumeration of sunburn cells (SBCs) in the first group of subjects (n = 16), whereas cyclobutyl pyrimidine dimers (CPDs) in DNA were determined in the second group (n = 13). The minimal erythema dose (MED) in each site was also determined in the first group of subjects. Sunburn cells and MEDs were re-evaluated in the first group 1 week after discontinuing AHA applications.

RESULTS

Glycolic acid caused enhanced sensitivity to UV light measured as increased SBC induction and lowered MEDs. Cyclobutyl pyrimidine dimers were elevated but not to a statistically significant level. No differences in SBCs or MEDs were evident after a week of discontinued treatments.

CONCLUSION

Short-term application of 10% glycolic acid sensitizes the skin to the damaging effects of UV light. This photosensitivity is reversed within a week of terminating treatments.

Hydroxycarboxylic Acids, N -Acetylamino Sugars, and N -Acetylamino Acids

Most alpha-hydroxyacids and polyhydroxy acids are physiologic, natural, and nontoxic substances. All members of the group promote normal keratinization and desquamation. Those with multiple hydroxyl groups are moisturizing antioxidants, and are especially gentle for sensitive skin. Alpha-hydroxyacids and polyhydroxy acids can increase biosynthesis of glycosaminoglycans and collagen fibers, and cause substantial skin plumping and increased dermal thickness. Formulation of alpha-hydroxyacids and polyhydroxy acids in combination with pharmaceutical agents can enhance efficacy and diminish or eliminate side effects and drug resistance. N-acetylamino sugars and N-acetylamino acids are two other categories of physiologic substances that can: 1) increase skin thickness; 2) improve wrinkles and photoaged skin; and 3) eradicate itch in senile and eczematous dermatitis.

Chemical peels

A chemical peel is a procedure in which a topically applied wounding agent creates smooth, rejuvenated skin by way of an organized repair process. This article describes the indications, classifications, operative procedure, and complications of chemical resurfacing. In addition, alternatives to chemoexfoliation are discussed.

A hairless mouse model for assessing the chronic toxicity of topically applied chemicals

An enormous number of synthetic chemicals are incorporated in topical drugs, cosmetics and toiletries. These have the potential to cause irritant reactions when chronically applied to human skin. In predictive tests for assessing the irritancy potential of these chemicals, haired species, especially rabbits, guinea pigs and mice, have figured prominently. Customarily these tests, including the renowned Draize rabbit test, have entailed a single acute exposure or at most daily exposures over a few weeks. Estimation of inflammation and tissue injury in these models have relied on visual assessment. We submit that this approach is no longer acceptable. Visual assessments are unreliable. Reactions which are scored equivalently by the naked eye may differ strikingly when examined histologically. Moreover, tissue injury may be present in clinically normal skin. Short-term results. even when abetted by routine histological evaluations, cannot predict the degree of injury from long-term exposures. Cosmetics and toiletries, for example, are used daily for decades, often over most of the lifespan of persons who are well groomed. We present the hairless mouse as a convenient, reliable model for assessing the chronic toxicity of diverse chemicals. Histological examination enables a detailed description of the different tissue components which participate in the complex cascade of changes that comprise the inflammatory response.

An evaluation of the effect of an alpha hydroxy acid-blend skin cream in the cosmetic improvement of symptoms of moderate to severe xerosis, epidermolytic hyperkeratosis, and ichthyosis

A number of genetic, intrinsic, and extrinsic factors can cause conditions of problem dry skin, marked by unusual dryness, rough texture, and extreme flaking and scaling, that are generally not controlled by conventional moisturizers. A study was undertaken to evaluate the safety and efficacy of two novel alpha hydroxy acid (AHA)-containing creams in reducing the appearance and symptoms of problem dry skin on subjects with a range of dry skin conditions, including xerosis, epidermolytic hyperkeratosis, and ichthyosis. Twenty subjects completed a course of treatment with either regular or extra strength AHA-blend cream on a test site, compared with a currently marketed, non-AHA moisturizing lotion on a control site. Subjects were treated for 4 weeks, with clinical evaluations performed at weeks 0, 2, and 4. The test for mulations reduced symptoms and improved cosmetic appearance following 2 weeks of use, with continued improvement following 4 weeks of use. Improvements were significant compared to baseline and compared to sites treated with the control lotion. Some patients experienced mild to moderate local adverse effects; all subjects were able to continue using the test product for the duration of the study.

Topical treatment of the aging face

This article discusses the various over-the-counter and prescription products available to help improve sun-damaged skin, as well as superficial peeling agents. Practical suggestions for treating patients are given.

Citric acid increases viable epidermal thickness and glycosaminoglycan content of sun-damaged skin

BACKGROUND

Recently, there has been an exponential increase in the use of alpha-hydroxy acids in dermatologic practice. Their inclusion in a myriad of cosmetic preparations underscores their popularity. Among the clinical effects of alpha-hydroxy acids are their ability to prevent the atropy resulting from potent topical corticosteroids, improve the appearance of photoaged skin, and correct disorders of keratinization. Despite this range of desirable effects, very little is known about the specific changes produced by various alpha-hydroxy acid preparations in the epidermis and dermal extracellular matrix. Previous work by others has demonstrated the ability of another alpha-hydroxy acid to increase viable epidermal thickness, and dermal glycosaminoglycans.

OBJECTIVE

In this study, we examined the effect of 20% citric acid lotion, as compared with vehicle alone, on skin thickness, viable epidermal thickness, and dermal glycosaminoglycan content. Biopsy samples were harvested after 3 months of treatment.

RESULTS

Image analysis of biopsy sections revealed increases in viable epidermal thickness and dermal glycosaminoglycans in treated skin.

CONCLUSIONS

Topical citric acid produces changes similar to those observed in response to glycolic acid, ammonium lactate, and retinoic acid including increases in epidermal and dermal glycosaminoglycans and viable epidermal thickness. Further studies of citric acid and other alpha-hydroxy acids are warranted to clarify their clinical effects and mechanisms of action.

Dermo-epidermal stimulation elicited by a beta-lipohydroxyacid: a comparison with salicylic acid and all-trans-retinoic acid

Although ageing has been thought to be irreversible, studies made during the last decade have shown that a few topical compounds may limit or improve the age-related skin damages. The efficacy of tretinoin (all-trans-retinoic acid) in treating photoageing is well established. Identifying other compounds with similar effect and improved tolerance would be greatly valued. In this double-blind study, a new beta-lipohydroxyacid compound was evaluated. To address a comparison between products, 6 volunteers completed a 4-week study using twice daily 0.025% tretinoin, 5% salicylic acid, 1.5% beta-lipohydroxyacid or vehicle. Immunohistochemistry and computerized image analysis were performed on skin sections from biopsies taken after treatment. We searched for changes in epidermal renewal (Ki-67 labeling), modifications in cytokeratin (56-65 kD) and filaggrin patterns, and in tumor necrosis factor alpha (TNF-alpha), Ulex europaeus and factor XIIIa expressively. The vehicle- and salicylic-acid-treated areas had an aspect similar to untreated control sites. Both beta-lipohydroxyacid and tretinoin induced enhanced epidermal proliferation and thickness with activation of factor XIIIa+dendrocytes. The effects were more pronounced at the tretinoin-treated site. We speculate that TNF-alpha might mediate some of the dermal effects. The beta-lipohydroxyacid mimics some of the stimulatory effects of tretinoin on the epidermis and dermis. This new compound should be listed among topical products boosting the skin tissues affected by ageing.

Epidermal and dermal effects of topical lactic acid

BACKGROUND

Many alpha-hydroxy acid products, containing low- or high-acid concentrations, are being used. It is not known whether different products perform differently or whether they modulate changes in both the epidermis and dermis.

OBJECTIVE

The purpose was to examine whether treatment with 5% and 12% lactic acid produces different cosmetic results and produces changes in the epidermis and dermis.

METHODS

Test participants applied either 5% or 12% lactic acid twice a day for 3 months. Changes in skin smoothness and texture, the depth and number of lines and wrinkles, and epidermal and dermal firmness and thickness were determined.

RESULTS

Treatment with 12% lactic acid resulted in increased epidermal and dermal firmness and thickness and clinical improvement in skin smoothness and in the appearance of lines and wrinkles. No dermal changes were observed after treatment with 5% lactic acid; however, similar clinical and epidermal changes were noted.

CONCLUSION

The results demonstrate that cosmetic benefits from the use of alpha-hydroxy acids are caused by modification of the skin surface, the epidermis and the dermis. Although 5% lactic acid modulates surface and epidermal changes, 12% lactic acid influences both the epidermis and the dermis.

Increased factor XIIIa transglutaminase expression in dermal dendrocytes after treatment with alpha-hydroxy acids: potential physiologic significance

BACKGROUND

Topical alpha-hydroxy acids (AHAs) have been shown to improve photoaging in human skin.

OBJECTIVE

We studied factor XIIIa transglutaminase expression in dermal dendrocytes (DDs) and mast cell degranulation after treatment of the skin with AHAs.

METHODS

Skin biopsy specimens obtained from patients after 4 to 8 months of treatment with lotions containing 25% AHAs were evaluated for factor XIIIa transglutaminase expression with immunoperoxidase and electron microscopy. Immunoperoxidase-stained sections were studied by means of semiquantitative methods and image analysis. Mast cell degranulation was studied by image analysis.

RESULTS

Increased factor XIIIa transglutaminase expression was seen after treatment with AHAs. All treated sites had increased scores compared with control sites by semiquantitative methods. Seventy-five percent of treated sites showed an increased mean area over control sites of factor XIIIa transglutaminase positivity with image analysis. These results correlated with an increased level of mast cell degranulation in treated sites and with activation of DDs as seen by electron microscopy.

CONCLUSION

Treatment of the skin with AHAs leads to mast cell degranulation and increased expression of factor XIIIa transglutaminase by activated DDs. Mast cell degranulation may lead to activation of DDs and increased factor XIIIa transglutaminase expression, via the action of tumor necrosis factor-alpha. We speculate that clinical and histologic improvement in photoaged skin after treatment with AHAs may be somehow related to this process.

[Effect of non-steroidal anti-inflammatory drugs on inflammatory reaction. An animal experiment study]

Previous investigations indicate that the application of a cyclooxygenase inhibitor alone can lead to amplification of the inflammatory process. To prevent this response a combination of flurbiprofen and leukotriene receptor antagonist (S 872419 A, Hoechst AG, Frankfurt/Main) were tested in an animal model. The right eye of 48 rabbits was burned with alcali (0.25 mol/l sodium hydroxide). Thirty animals were treated with (0.03% flurbiprofen sodium eye drops and 1% S872419 A eye drops, five times daily). Eighteen animals received no therapy for up to 14 days. Hyperemia of the limbal vessels, corneal vascularization, the number of PMNLs in the cornea and the prostacyclin level in the anterior chamber of the eye (ELISA) served as criteria. On day 3, after the chemical burn only the therapy group showed a significant decrease in hyperemia of the limbal vessels (14th day: score with therapy 0.3, without 2.17, P < 0.05). Without therapy corneal vascularization filled a much larger area from the 6th day on (14th day: area with therapy 3.5 mm2, without 63.7 mm2, P < 0.05). The number of PMNLs was effectively limited by therapy in the superficial stromal layers of the cornea and with therapy showed 2.4 cells/0.014 mm2 and without 18 cells/0.014 mm2 after 48 h. Without Therapy the level of prostacyclin was up to 15 times higher than with (12-h value with therapy) 607 pg/ml, without 9094 pg/ml, P < 0.05). Suppression of cyclo- and lipoxygenase-mediated inflammatory responses is possible with the combination of flurbiprofen and S 872419 A when two arachidonic by inhibition of prostanoid synthesis and leukotriene receptor block at the same time.

Pharmacokinetics, safety and tolerability of the orally administered receptor antagonist of cysteinyl-leukotrienes BAY x 7195 in single-dose escalation studies

BAY x 7195 is a novel receptor antagonist of cysteinyl-leukotrienes currently under development for the treatment of asthma. It is effective in antagonizing the leukotriene-D4 induced bronchoconstriction in healthy volunteers following oral administration. The pharmacokinetics, safety and tolerability of the drug were investigated in six partially placebo-controlled studies in healthy volunteers with single oral administration of a 50, 100, 250, 500 and 1000 mg dose as a tablet. The drug was well tolerated. The only remarkable adverse event was diarrhea in one volunteer receiving the highest dose of 1000 mg. There were no additional clinically relevant changes in any safety parameter including laboratory values. Concentrations of BAY x 7195 were determined in plasma and urine by high performance liquid chromatography with fluorescence detection and plasma-concentrations were further evaluated by compartmental and non-compartmental methods. The concentration vs time profiles of the drug were biphasic with a dominant t1/2 of 0.5-2 h and a terminal t1/2 of 5-10 h. Pharmacokinetics were linear in the investigated range of doses. In spite of substantial inter-subject variability intra-individual variability in AUC and Cmax was reasonable. In general, the concentration vs time profiles could be described with a 2-compartment body model. However, in some cases the occurrence of second and third concentration maxima necessitated the use of a multiple segment absorption model to accomplish a good fit to the data. Enterohepatic recirculation following glucuronidation of the drug is the likely reason for the multiple peaks. Urinary excretion of BAY x 7195 and its glucuronide metabolite was negligible the amount excreted into urine from 0 to 48 h being < 0.1% of the dose. The low renal clearance of BAY x 7195 (< or = 0.07 ml/min) is suggestive of significant reabsorption in the renal tubuli taking into account that the expected renal clearance for a drug with 99.5% protein binding is about 0.6 ml/min.

Blockade of ATP-sensitive potassium channels by 5-hydroxydecanoate suppresses monophasic action potential shortening during regional myocardial ischemia

We tested 5-hydroxydecanoate (5-HD), a specific blocker of ATP-sensitive potassium channels (IK.ATP), to determine if mitigates electrophysiologic changes produced by regional myocardial ischemia in vivo. A sequence of 5-minute occlusion of the distal LAD and 30-minute reperfusion was repeated while recording the monophasic action potential (MAP) and bipolar electrogram (EG) from the epicardial center of the ischemic myocardium in anesthetized dogs. 5-HD (30 mg/kg, i.v.) or glibenclamide (0.15 or 0.3 mg/kg, i.v.) was administered before the third occlusion, and the data were compared to the second occlusion data. 5-HD did not affect baseline MAP duration at 90% and 50% repolarization (APD90, APD50) before LAD occlusion but suppressed occlusion-induced shortening of APD90 (16 +/- 2% during the second occlusion vs. 5 +/- 3% during the third occlusion, n = 8, p < 0.01) and APD50 (16 +/- 3% vs. 10 +/- 3%, n = 8, p < 0.05). Pretreatment with glibenclamide also suppressed occlusion-induced MAP shortening and eliminated an additional effect of 5-HD (n = 3). 5-HD did not affect the occlusion-induced increase in duration and activation time of EG. 5-HD, as well as glibenclamide, suppressed regional ischemia-induced MAP shortening, probably by blocking activation of IK.ATP, without affecting conduction delay. These differential effects of 5-HD on repolarization and conduction during the early phase of regional ischemia might have the potential to suppress reentrant ventricular arrhythmias.