Drug-free Vehicle Research Articles

A shea butter-based ketamine ointment: The antidepressant effects of transdermal ketamine in rats

The delayed onset of monoaminergic antidepressants and disadvantages of traditional administration routes created the need for alternative non-invasive delivery methods with rapid onset therapeutic effect. Ketamine attracted attention as a fast-acting glutamatergic antidepressant with ideal physiochemical properties for alternative routes of administration. However, there is no sufficient data for its transdermal use in depression. In this proof-of-concept study, we investigated the antidepressant effects of transdermal ketamine delivered via a novel ointment with skin protective, emulsifying and permeation enhancing properties. A shea butter-based 5% (w/w) ketamine ointment or a drug-free vehicle ointment were applied to the shaved dorsal skin of male Wistar rats for 2 days, twice a day. Behavioral despair, locomotor activity and anxiety-like behavior were respectively assessed in the forced swim test (FST), open field test (OFT), and elevated plus maze (EPM). The pharmacokinetic profile of the ointment was analyzed with high-performance liquid chromatography. Transdermal ketamine ameliorated behavioral despair without altering general locomotor activity and anxiety-like behavior, showing that skin-friendly drug carriers like shea butter may constitute promising alternatives to current routes of delivery for ketamine. Tested transdermal method aims to provide more sustainable drug delivery for long-term treatment schedules. Future studies can investigate its long-term use, side effects and abuse liability.

Reinforcing effects of fentanyl and sufentanil aerosol puffs in rats.

Rapidly evolving e-cigarette technology developed for self-administering nicotine aerosol has the potential to be utilized to self-administer other aerosolized drugs of abuse. Rodent models which mirror characteristics of human e-cigarette use are necessary to explore the degree to which this may be a public health concern. Our goal was to develop a highly translational model of discrete nose-only aerosol puff drug delivery to explore the reinforcing effects of fentanyl and sufentanil aerosols in rats. Male and female Sprague-Dawley rats were trained to perform a multiple schedule FR1 lever-press, 4-s (second) nose hold operant during which the subject's orofacial areas were exposed to drug-free glycerol/propylene glycol aerosol produced by a commercial e-cigarette at a power setting of 18 watts. Each completed 4-s drug-free vehicle aerosol exposure resulted in a 3-s presentation of a 0.1-ml dipper of sweetened milk solution. After training, rats were then allowed to self-administer 4-s nose-only puffs of fentanyl (100-6000µg/ml) or sufentanil (30-500µg/ml) aerosol in the absence of paired milk dipper reinforcers. All 31 rats learned the lever-press/nose-poke multiple schedule for milk dippers alone and 25 accepted exposure to 4s of 18watts of drug-free vehicle aerosol when paired with milk dipper presentations. In the absence of paired milk dipper presentations, fentanyl aerosol puffs at concentrations of 1000 and 3000µg/ml as well as 100µg/ml puffs of sufentanil served as reinforcers compared to both air puffs and drug-free vehicle aerosol puffs. There were no significant differences between males and females in number of fentanyl or sufentanil puffs self-administered. Discrete nose-only puffs of two potent opioids under exposure conditions comparable to puff durations in human e-cigarette users serve as reinforcers in rats. This outcome suggests that under appropriate conditions e-cigarettes might be a potential alternative delivery mechanism for illicit opioids.

Neuroprotective Effect of Alpha-asarone on the Rats Model of Cerebral Ischemia–Reperfusion Stroke via Ameliorating Glial Activation and Autophagy

Alpha-asarone, a major active component isolated from Acorus gramineus, can affect brain functions and behaviors by multiple mechanisms. However, the effect of alpha-asarone on cerebral ischemia–reperfusion (CIR) stroke has not been reported. The present study aimed to investigate the neuroprotective effect of alpha-asarone and the involved mechanisms against CIR stroke. Rats were subjected to middle cerebral occlusion (MCAO) for 2 h. Then the drug or drug-free vehicle was intravenously injected to corresponding groups. After reperfusion for 24 h, the infarct volume was evaluated by Triphenyl Tetrazolium Chloride (TTC) staining. The neurofunctional recovery and post-stroke epilepsy were evaluated. Nissl and Hematoxylin–Eosin (H&E) staining were used for histological observation. We investigated the protective mechanism of alpha-asarone against the stroke. The results showed that alpha-asarone exhibited a desirable neuroprotective effect, manifested as reducing infarct volume and post-stroke epilepsy and improving neurological function. Histological and flow cytometry analysis revealed that alpha-asarone treatment alleviated cell injury and apoptosis in vivo and in vitro. Furthermore, alpha-asarone decreased GFAP, Iba-1, and LC3II/LC3I expression and increased the expression of p62. These results suggested that alpha-asarone attenuated the CIR stroke injury via ameliorating glial activation and autophagy.

Differential Expression of Neuroinflammatory mRNAs in the Rat Sciatic Nerve Following Chronic Constriction Injury and Pain-Relieving Nanoemulsion NSAID Delivery to Infiltrating Macrophages.

The neuroinflammatory response to peripheral nerve injury is associated with chronic pain and significant changes in the molecular expression profiles of mRNAs in neurons, glia and infiltrating immune cells. Chronic constriction injury (CCI) of the rat sciatic nerve provides an opportunity to mimic neuropathic injury and quantitatively assess behavior and differential gene expression in individual animals. Previously, we have shown that a single intravenous injection of nanoemulsion containing celecoxib (0.24 mg/kg) reduces inflammation of the sciatic nerve and relieves pain-like behavior for up to 6 days. Here, we use this targeted therapy to explore the impact on mRNA expression changes in both pain and pain-relieved states. Sciatic nerve tissue recovered from CCI animals is used to evaluate the mRNA expression profiles utilizing quantitative PCR. We observe mRNA changes consistent with the reduced recruitment of macrophages evident by a reduction in chemokine and cytokine expression. Furthermore, genes associated with adhesion of macrophages, as well as changes in the neuronal and glial mRNAs are observed. Moreover, genes associated with neuropathic pain including Maob, Grin2b/NMDAR2b, TrpV3, IL-6, Cacna1b/Cav2.2, Itgam/Cd11b, Scn9a/Nav1.7, and Tac1 were all found to respond to the celecoxib loaded nanoemulsion during pain relief as compared to those animals that received drug-free vehicle. These results demonstrate that by targeting macrophage production of PGE2 at the site of injury, pain relief includes partial reversal of the gene expression profiles associated with chronic pain.

Effects of in vitro, acute and chronic treatment with fluoxetine on the sympathetic neurotransmission of rat vas deferens.

It is described that fluoxetine treatment is able to induce ejaculatory disorders. However, the exact mechanism is still not fully understood. Therefore, this study was carried out to further evaluate the anti-ejaculatory effects of fluoxetine, using different approaches (in vitro or in vivo treatments), on the sympathetic neurotransmission of the rat vas deferens. Vas deferens from male Wistar rats were used to check the in vitro effects of fluoxetine 10-6M, 3.10-6M or 10-5M. Animals were also acutely (20mg/kg, i.p. 4h or 24h) or chronically (10mg/kg, i.p., 30days) treated with fluoxetine or drug-free vehicle. The vas deferens from non-treated and treated animals were isolated and mounted in an isolated organ bath for the study of the contractions induced by adrenergic agonists, tyramine, 5-HT, Ca2+ or electrical field stimulation. In vitro or acute treatment with fluoxetine decreased the contraction induced by agonists, Ca2+ or electrical field stimulation. The chronic treatment with fluoxetine decreased the contractions induced agonists, tyramine or Ca2+, but did not modify the contractions induced by electrical field stimulation. We have shown that in vitro or in vivo fluoxetine treatment is able to alter the sympathetic neurotransmission of the rat vas deferens which could be related to alterations in the calcium signalling.

Iloprost reverses established fibrosis in experimental right ventricular failure.

Prostacyclin and its analogues improve cardiac output and functional capacity in patients with pulmonary arterial hypertension (PAH); however, the underlying mechanism is not fully understood. We hypothesised that prostanoids have load-independent beneficial effects on the right ventricle (RV). Angio-obliterative PAH and RV failure were induced in rats with a single injection of SU5416 followed by 4 weeks of exposure to hypoxia. Upon confirmation of RV dysfunction and PAH, rats were randomised to 0.1 μg·kg(-1) nebulised iloprost or drug-free vehicle, three times daily for 2 weeks. RV function and treadmill running time were evaluated pre- and post-iloprost/vehicle treatment. Pulmonary artery banded rats were treated 8 weeks after surgery to allow for significant RV hypertrophy. Inhaled iloprost significantly improved tricuspid annulus plane systolic excursion and increased exercise capacity, while mean pulmonary artery pressure and the percentage of occluded pulmonary vessels remained unchanged. Rats treated with iloprost had a striking reduction in RV collagen deposition, procollagen mRNA levels and connective tissue growth factor expression in both SU5416/hypoxia and pulmonary artery banded rats. In vitro, cardiac fibroblasts treated with iloprost showed a reduction in transforming growth factor (TGF)-β1-induced connective tissue growth factor expression, in a protein kinase A-dependent manner. Iloprost decreased TGF-β1-induced procollagen mRNA expression as well as cardiac fibroblast activation and migration. Iloprost significantly induced metalloproteinase-9 gene expression and activity and increased the expression of autophagy genes associated with collagen degradation. Inhaled iloprost improves RV function and reverses established RV fibrosis partially by preventing collagen synthesis and by increasing collagen turnover.

Meta-Analysis of Randomized Clinical Trials Investigating the Effect of TDT 064, a Gel-Based Formulation Containing Ultra-Deformable Phospholipid Vesicles, in Patients with Knee Osteoarthritis

Background: Ketoprofen-containing ultra-deformable phospholipid vesicles (IDEA-033) have been compared with drug-free vehicle (TDT 064) in randomized, controlled trials in knee osteoarthritis (OA). A pronounced treatment effect was reported for TDT 064, with an effect size (ES) comparable with celecoxib in one trial. Our meta-analysis determined whether these TDT 064 effects are beyond any expected placebo effect. Methods: Five randomized, placebo-controlled studies of IDEA-033 in knee OA using TDT 064 as a control were included. Change from baseline in Western Ontario and McMaster Universities (WOMAC) OA Index pain and function subscale scores from each study were standardized and the ES calculated at various times. We compared our results with previously reported data on placebo response using similar methodology in a meta-analysis of 198 randomized OA trials. Results: ES for pain relief at Week 6 was markedly higher for TDT 064 studies (ES: 1.04 [95% confidence interval (CI): 0.98–1.09]) than that previously reported for placebos in knee OA (ES: 0.54 [95% CI: 0.49–0.60]), as was the ES for function improvement (ES: 0.93 [95% CI: 0.87–0.98] vs ES: 0.49 [95% CI: 0.44–0.54], respectively). Higher ES for pain relief for TDT 064 studies was also reported with prior oral nonsteroidal anti-inflammatory drugs (NSAIDs) exposure (ES: 1.00 [95% CI: 0.93–1.07]), and in patients with high (ES: 1.08 [95% CI: 1.00–1.17]) or low baseline pain (ES: 1.03 [95% CI: 0.95–1.11]). Conclusions: The magnitude of the effect with TDT 064 indicates this is unlikely to be solely a result of a placebo response.

Abstract P6-04-08: Cytosolic phospholipase A2 (cPLA2) as a therapeutic target in basal-like breast cancer

Abstract Introduction: Basal-like breast cancer is frequently associated with triple negative phenotype, and there is a need for novel therapeutic strategies for this patient population. Inhibitors of cytosolic phospholipase A2 (cPLA2) have been suggested to block both MAPK and PI3K signalling and have a high potential for activity in basal-like breast cancer (Lin 1993, Wen 2013). In this study, we compared the expression of PLA2G4A between luminal B and basal-like breast cancer, both in patient-derived xenograft models (PDX) and human cancer tissue. In addition, we studied the effect of the novel cPLA2 inhibitor AVX235 on tumor growth in a basal-like PDX model. Materials and methods: Tumor tissue specimens were obtained from PDX models (n = 26) and a clinical breast cancer biobank (n = 32). Gene expression analysis was carried out on Agilent 8×60K microarrays. The expression of 54 genes directly involved in choline metabolism was examined. Differential expression of choline genes between basal-like and luminal B tumors was calculated by subtraction of log2 expression values. Mice carrying bilateral MAS98.12 basal-like xenografts (Bergamaschi 2009) were treated with the cPLA2 inhibitor AVX235 (30 mg/kg i.p. daily for 7 days then every second day for 14 days, n = 6) or drug-free vehicle (control group, n = 6). Results: The PDX models were subtyped into basal-like (n = 19) and luminal B (n = 7) subtypes based on the expression of 500 intrinsic genes [Sørlie 2003]. For the human cancer tissue, there were 18 basal-like and 14 luminal B tumors. There was a significant correlation between differential choline gene expression in basal-like vs luminal B tumors in PDX models and human cancer tissue (p<1.3*10−12). Both in PDX models (p<0.04) and human cancer tissue (p<0.0003), PLA2G4A was significantly higher expressed in basal-like than luminal B tumors. Treatment with AVX235 markedly reduced the growth rate of MAS98.12 xenografts compared to controls. After 19 treatmment days, the mean tumor volume (normalised to volume at start of treatment) in the treatment group was 36% of the tumor volume in the control group, the difference being statistically significant (p = 0.023). No signs of treatment-related adverse effects were observed. Conclusion: PLA2G4A is higher expressed in basal-like than in luminal B breast cancer. Treatment with the cPLA2 inhibitor AVX235 significantly inhibits tumor growth. These data suggest that cPLA2 inhibitors may be of particular value in treatment of basal-like breast cancer.

Abstract 2584: Inhibition of Mitochondrial Permeability Transition with NIM811 Improves Functional Recovery after Focal Cerebral Ischemia

Introduction: Mitochondrial dysfunction plays a seminal role in acute ischemic neuronal degeneration, the signature injury in stroke. A selective inhibitor of mitochondrial permeability transition (mPT) may prevent collapse of the mitochondrial membrane potential, thereby inhibiting the intrinsic pathway to neuronal death. Hypothesis: A novel mPT inhibitor, NIM811, will reduce infarct volume and improve functional recovery after focal cerebral ischemia. Methods: NIM811 was obtained as a gift from Novartis Pharma Ltd. (Basel, Switzerland). Focal cerebral ischemia was induced by unilateral carotid and middle cerebral artery occlusion for 2 hrs in male spontaneously hypertensive rats (SHRs). During post-ischemic reperfusion, animals received NIM811 (50 mg/kg at 1- and 24-hrs of post-ischemic reperfusion) or drug-free vehicle. Infarct volume was measured at 24 hrs or 7 days. Functional performance was assessed with 2 measures, fall latency time (FLT) in a Rotarod device and Removal Delay (RD) in a tape removal task, over 28 days. Results: When given after 1 hr of post-ischemic reperfusion, 50 mg/kg NIM811 reduced 24-hr infarct volume (63.6 ± 18.7 [SD] v. 89.3 ± 12.5 mm 3 in controls; n = 8 - 10/group; p ≤ 0.01; unpaired t -test). Serial dosing of NIM811 lowered 7-day infarct volume compared to controls (51.9 ± 7.4 v. 61.9 ± 10.3 mm 3 ; n = 13 - 16/group; p ≤ 0.01; unpaired t -test). In the Rotarod task, NIM811-treated animals had prolonged FLT over controls at all examination times up to 28 days (n = 7 per group; p ≤ 0.0001; ANOVA/Scheffe’s test). NIM811-treated SHRs also had shorter RD for discarding tape applied to the paretic forelimb, compared to controls (n = 7 per group; p ≤ 0.002; ANOVA/Scheffe’s test). Conclusions: Inhibition of mPT with NIM811 significantly reduced infarct volume, when given within a clinically relevant post-ischemic interval. Serial dosing of NIM811 achieved neuroprotective resilience at 7 days. Reductions in infarct volume by NIM811 were complemented by improved functional performance up to 28 days after ischemia. These promising results highlight the potential of NIM811 for neuroprotective treatment of stroke in man.

Abstract 9434: A Specific IKK Inhibitor Suppresses Experimental Autoimmune Myocarditis in Rats

Introduction: Nuclear factor-kappa B (NF-κB), which is regulated by the inhibitor NF-κB kinase (IKK), plays a critical role in the development of myocarditis. However, little is known about the role of IKK in its pathophysiology. Hypothesis: We assessed the hypothesis that IKK inhibition could attenuate cardiac inflammation in the progression of myocarditis. Methods: Lewis rats were immunized with porcine cardiac myosin to induce experimental autoimmune myocarditis (EAM). We administered the IKK inhibitor (IMD-0354, 15mg/kg/day, n=6) to EAM rats daily; the drug-free vehicle was used as untreated EAM control (n=7). We analyzed the therapeutic effects of IKK inhibition against EAM using echocardiography and pathological examination. Cytokine expression in the hearts and cell proliferation by myosin restimulation were also analyzed. Results: Echocardiogram revealed that the IKK inhibitor improved left ventricular fractional shortening (52.7±4.5%) in comparison to the untreated group (37.3±3.1%, p<0.05). Pathologically, severe myocardial cell infiltration was observed in the untreated EAM group (affected area per whole heart, 55.8±6.1%), while the IKK inhibitor treated group showed to suppress these changes (26.3±4.2%, p<0.05). In the IKK inhibitor treated group, mRNA expression of IFN-gamma (3.9 ±0.7 fold vs. untreated group, p<0.05) and MCP-1 (17.1±0.8 fold vs. untreated group, p<0.05) was significantly suppressed in comparison to the untreated EAM group (IFN-gamma: 14.5±2.7 fold, MCP-1: 51.4±3.9 fold). Moreover, the IKK inhibitor suppressed production of IL-2 and T cell proliferation in a dose dependent manner in vitro. Conclusion: In conclusion, the IKK inhibitor ameliorated EAM by suppressing cytokine production and attenuating inflammatory cell infiltration. IKK regulation is a promising treatment of clinical myocarditis.

The Inhibitor of NF-κB Kinase Plays a Pivotal Role in the Development of Autoimmune Myocarditis in Rats

Background: Nuclear factor-kappa B (NF-κB), which is regulated by inhibitor of NF-κB kinase (IKK), plays a critical role in the development of myocarditis. However, little is known about the role of IKK in its pathophysiology. We assessed the hypothesis that IKK inhibition could attenuate cardiac inflammation in the progression of myocarditis. Materials and Methods: We administered the IKK inhibitor (IMD-0354, 15mg/kg/day) to experimental autoimmune myocarditis (EAM) rats daily (n=6). The drug-free vehicle was used as control (n=6).

Antiretroviral nucleosides, deoxynucleotide carrier and mitochondrial DNA: evidence supporting the DNA pol γ hypothesis

Nucleoside reverse transcriptase inhibitors (NRTIs) exhibit mitochondrial toxicity. The mitochondrial deoxynucleotide carrier (DNC) transports nucleotide precursors (or phosphorylated NRTIs) into mitochondria for mitochondrial (mt)DNA replication or inhibition of mtDNA replication by NRTIs. Transgenic mice (TG) expressing human DNC targeted to murine myocardium served to define mitochondrial events from NRTIs in vivo and findings were corroborated by biochemical events in vitro. Zidovudine (3'-azido-2',3'-deoxythymidine; ZDV), stavudine (2', 3'-didehydro-2', 3'-deoxythymidine; d4T), or lamivudine ((-)-2'-deoxy-3'-thiacytidine; 3TC) were administered individually to TGs and wild-type (WT) littermates (35 days) at human doses with drug-free vehicle as control. Left ventricle (LV) mass was defined echocardiographically, mitochondrial ultrastructural defects were identified by electron microscopy, the abundance of cardiac mtDNA was quantified by real time polymerase chain reaction, and mtDNA-encoded polypeptides were quantified. Untreated TGs exhibited normal LV mass with minor mitochondrial damage. NRTI monotherapy (either d4T or ZDV) increased LV mass in TGs and caused significant mitochondrial destruction. Cardiac mtDNA was depleted in ZDV and d4T-treated TG hearts and mtDNA-encoded polypeptides decreased. Changes were absent in 3TC-treated cohorts. In supportive structural observations from molecular modeling, ZDV demonstrated close contacts with K947 and Y951 in the DNA pol gamma active site that were absent in the HIV reverse transcriptase active site. NRTIs deplete mtDNA and polypeptides, cause mitochondrial structural and functional defects in vivo, follow inhibition kinetics with DNA pol gamma in vitro, and are corroborated by molecular models. Disrupted pools of nucleotide precursors and inhibition of DNA pol gamma by specific NRTIs are mechanistically important in mitochondrial toxicity.

Early treatment with cGMP phosphodiesterase inhibitor ameliorates progression of renal damage

Chronic renal disease is associated with oxidative stress and reduced nitric oxide availability which, in turn, promotes hypertension and further progression of renal damage. Most actions of nitric oxide are mediated by cyclic 3',5' guanosine monophosphate (cGMP) which is rapidly degraded by phosphodiesterases (PDE). Therefore, we investigated if inhibition of PDE-5 would retard the progression of chronic renal failure. We studied rats with 5/6 nephrectomy treated with sildenafil (2.5 mg/kg(-1)/day(-1)) in two experimental protocols. In the first protocol, we started sildenafil therapy immediately after renal ablation and continued treatment for 8 weeks. Control groups consisted of rats with renal ablation treated with drug-free vehicle and sham-operated rats with and without sildenafil treatment. In these studies, sildenafil treatment prevented hypertension and deterioration of renal function, reduced histologic damage, inflammation and apoptosis, delayed the onset of proteinuria, and preserved renal capillary integrity. In the second protocol we compared sildenafil with losartan (7.5 mg/kg(-1)/day(-1)) and the combination of both drugs in established renal disease, starting these drugs 4 weeks after 5/6 nephrectomy. Delayed sildenafil treatment failed to improve proteinuria and glomerulosclerosis but ameliorated hypertension and azotemia. These observations suggest that currently available PDE-5 inhibitors have potential clinical value in the treatment of chronic renal disease.

Functional and structural reversibility of H-7 effects on the conventional aqueous outflow pathway in monkeys

To determine the mechanism of H-7-induced outflow resistance decrease, the reversibility of H-7 effects on outflow pathway was studied physiologically and morphologically in live monkey eyes. Total outflow facility was measured by two-level constant pressure perfusion before (baseline measurement) and after (post-drug measurement) anterior chamber (AC) exchange with 300 μ m H-7 or vehicle in opposite eyes of eight monkeys. H-7 was then removed by AC exchange with drug-free vehicle in both eyes, followed by a 2·5 hr waiting period, after which outflow facility was measured again with (Group 2; n=4) or without (Group 1; n=4) another preceding drug-free AC exchange. For morphological study, five monkeys were initially perfused similarly to Group 1 in physiology, but the facility measurement beginning 2·5 hr after drug removal was either omitted or replaced by gold solution infusion. Following baseline measurement, two of the five monkeys received H-7 or vehicle in opposite eyes, while three monkeys received H-7 in both eyes 2·5 hr apart, contributing one H-7-treated ‘recovery’ eye and one H-7-treated ‘acute’ eye. After perfusion, both eyes of all five monkeys were studied by light and electron microscopy. Outflow facility during post-drug measurement in the H-7-treated eye was significantly increased by two-fold. However, the facility increase was reduced when measured beginning 2·5 hr after drug removal, with the reduction being greater in Group 1. ‘Recovered’ outflow facility after drug removal gradually increased again under continuous AC infusion with drug-free vehicle. Morphologically, major changes in and around Schlemm's canal (SC) in the H-7-treated ‘acute’ eye included protrusion of the entire inner wall (IW) into SC, relaxation of the IW cells and reorganization of the IW cytoskeleton. The changes in IW cells and juxtacanalicular region of the H-7-treated ‘recovery’ eye were non-uniform, with areas resembling the vehicle-treated eye (‘contracted areas’) and areas resembling the H-7-treated ‘acute’ eye (‘relaxed areas’). The average junction-to-junction distances in the IW cells of the H-7-treated ‘recovery’ eye were intermediate between the vehicle-treated eye and the H-7-treated ‘acute’ eye. In conclusion, H-7’s effect on outflow facility seems reversible, but AC exchange or continuous infusion with drug-free vehicle can re-elevate the ‘recovered’ outflow facility. Major morphological changes in the TM immediately after H-7 include IW protrusion, cellular relaxation and cytoskeleton reorganization. The decrease in ‘relaxed areas’ in the TM, in conjunction with the reversed outflow facility, 2·5 hr after drug removal suggests that cellular relaxation in the TM is the structural basis for H-7-induced increase in outflow facility.

Anti-Irritative Effect of Methylrosaniline Chloride (Gentian Violet)

Background: There are no published studies of the effect of methylrosaniline chloride (MRC) on inflammation when used at the concentration recommended in the New German Formulary. A tissue-damaging effect has been described in animal studies and at higher concentrations in humans. Objective: To determine whether 0.5% MRC increases or reduces skin damage in irritative dermatitis. Methods: The study was carried out on the sodium lauryl sulfate (SLS) skin irritation model in 18 healthy volunteers. The impact of intermittent treatment with 0.5% MRC or drug-free vehicle on three SLS exposure effects was determined: reduction of stratum corneum water content (corneometry), increase in subpapillary blood flow (laser Doppler method) and barrier damage (transepidermal water loss). Results: MRC produced significant reductions in all three SLS exposure effects. Conclusions: Treatment of irritative dermatitis with 0.5% MRC is expected to produce a high clinical efficacy not only because of the compound’s established antimicrobial activity, but also because of its anti-irritative effect.

A clinical evaluation of a novel liposomal carrier for acyclovir in the topical treatment of recurrent herpes labialis

In a 2-armed, double-blind, randomized clinical study, the efficacy in the treatment of recurrent herpes labialis of 5% acyclovir in a novel liposomal carrier (ethosome) was evaluated in comparison with that of a commercial 5% acyclovir cream (Zovirax cream) and that of a drug-free vehicle. Data were based on 61 herpetic episodes in 40 subjects. In a crossover arm in which the 2 active preparations were compared, the time to crusting of lesions was significantly shorter ( P < .025) with the ethosomal acyclovir (1.8 days) than with the cream (3.5 days). Time to loss of crust was also significantly shorter (4.2 vs 5.9 days; P < .05). In a parallel arm in which all 3 preparations were compared, the time to crusting with the ethosomal acyclovir (1.6 days) was significantly shorter than the time with the acyclovir cream (4.3 days; P < .02) and the time with the drug-free vehicle (4.8 days; P < .005); in this arm, the shorter time to loss of crust for the ethosome (3.5 days), in comparison with the times for the cream (6.4 days) and the drug-free vehicle (6.1 days), did not reach statistical significance. Approximately 30% of all episodes treated with the ethosome were clinically abortive; this compared with 10% of those treated with the cream or the drug-free vehicle. No adverse effects were reported, other than minor burning sensations at the application site that lasted a few seconds after application and were evenly distributed between the investigated preparations. This pilot study suggests the improved clinical efficacy of the new liposomal preparation in comparison with Zovirax cream in the treatment of recurrent herpes labialis. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:700-5)

INHIBITION OF CYTOMEGALOVIRUS IN VITRO AND IN VIVO BY THE EXPERIMENTAL IMMUNOSUPPRESSIVE AGENT LEFLUNOMIDE

825 Despite progress in antiviral chemotherapy, cytomegalovirus (CMV) continues to complicate the clinical course of many allograft recipients. Enhancement of viral activity by requisite immune suppression frequently engages the clinician in a struggle to balance graft preservation with control of CMV disease. Leflunomide, an inhibitor of protein tryrosine kinase activity and pyrimidine synthesis, is an experimental immunosuppressive agent with demonstrated effectiveness against acute and chronic rejection in animal models. We have recently discovered that the active metabolite of this agent, A77 1726, inhibits the production of multiple isolates of human CMV in both human fibroblasts and endothelial cells in vitro. Viral plaque assays demonstrated a consistent dose-dependent reduction of virus yield over a range of concentrations equivalent to those which inhibit in vitro immune activation. Unlike anti-CMV drugs currently in use, A77 1726 has no effect upon viral DNA synthesis, as demonstrated by CMV-specific DNA dot blot analysis and direct biochemical assay of viral DNA polymerase activity. Rather, as indicated by transmission electron microscopy, this agent appears to act at the level of virion assembly by interfering with nucleocapsid tegumentation, possibly by inhibition of tegument protein phosphorylation. Likely as a consequence of this unique mechanism of action, A77 1726 is equally effective against drug-resistant isolates. To determine the effectiveness of leflunomide in the control of viral load in vivo, groups of immunodeficient nude rats were inoculated with rat CMV (RCMV, Maastricht strain, 105 plaque-forming units/animal, IP) and treated with either leflunomide (15 mg/kg/day for 14 days), ganciclovir (10 mg/kg/day for 5 days), or drug-free vehicle. Experiments also included uninfected control animals. Following euthanization at 14 days post-inoculation, viral infection was confirmed by histologic observation of typical cytomegalic ductal epithelium in salivary glands, and further verified by immunohistochemical detection of RCMV antigens in multiple tissues. Plaque assay of tissue homogenates prepared from salivary gland, spleen, and lung demonstrated 75-99% reduction in virus yield in organs harvested from leflunomide-treated animals, and 85-99% reduction in those harvested from ganciclovir-treated animals. No virus was ever recovered from uninfected control rats. Thus in addition to its in vitro antiviral activity, leflunomide is capable of reducing viral load in vivo. These findings imply that leflunomide, an effective immunosuppressive agent, shows potential to concurrently attenuate a major complication of immunosuppression, CMV disease, by a novel mechanism of antiviral activity.

Comparison of skin atrophy and vasoconstriction due to mometasone furoate, methylprednisolone and hydrocortisone

Topical glucocorticoids with improved benefit/risk ratio are of great interest in dermatology, but there are very few trials directly comparing the efficacy and side-effects of these new preparations. In our study the vasoconstrictor effect and side-effects of two of these new glucocorticoids were evaluated and blanching effect was determined by two-dimensional laser scanning. In a randomised, double blind intra-individual comparative trial, 10 subjects were treated with various glucocorticoids or drug-free vehicle. The test drugs were mometasone furoate (MF), methylprednisolone aceponate (MP) and hydrocortisone (OH-C). The preparations were tested for a period of 3 weeks with occlusion on the flexor side of the forearm. Skin thickness and vasoconstriction were determined using 20 MHz ultrasound scanning, laser Doppler scanning (LDS) and chromometry. No adverse effects were observed during the observation period. Only partial vasoconstriction occurred in most cases during the observation period. MP and MF produced maximal blanching between days 3 and 5 of treatment, while with OH-C clinically visible blanching did not occur. Ultrasound evaluation of skin thickness showed similar behaviour for all three steroids tested: there were no signs of skin atrophy in any of the cases. LDS evidenced hypoperfusion of a test area on the perfusion image in only a few patients and there were no significant differences between the steroids tested. On evaluation of vasoconstriction caused by the steroids tested using chromometry there was a significant difference between MF and OH-C on the L*a*b* scale (P < 0.005). Only at day 3 was a blanching effect caused by MP and MF demonstrable (a-value, P < 0.05). In summary, the synthetic steroids MF and MP presented side-effects similar to those of OH-C but much greater vasoconstrictor effect; after an application period of over 5 days under occlusion a blanching effect in our model was not demonstrable by means of chromometry. Two-dimensional laser scanning offers no advantage in the evaluation of the blanching effect in comparison to one-dimensional laser fluxmetry (LDF).

Comparison of skin atrophy and vasoconstriction due to mometasone furoate, methylprednisolone and hydrocortisone

Background/aims Topical glucocorticoids with improved benefit/risk ratio are of great interest in dermatology, but there are very few trials directly comparing the efficacy and side-effects of these new preparations. In our study the vasoconstrictor effect and side-effects of two of these new glucocorticoids were evaluated and blanching effect was determined by two-dimensional laser scanning.Methods In a randomised, double blind intra-individual comparative trial, 10 subjects were treated with various glucocorticoids or drug-free vehicle. The test drugs were mometasone furoate (MF), methylprednisolone aceponate (MP) and hydrocortisone (OH-C). The preparations were tested for a period of 3 weeks with occlusion on the flexor side of the forearm. Skin thickness and vasoconstriction were determined using 20 MHz ultrasound scanning, laser Doppler scanning (LDS) and chromometry.Results No adverse effects were observed during the observation period. Only partial vasoconstriction occurred in most cases during the observation period. MP and MF produced maximal blanching between days 3 and 5 of treatment, while with OH-C clinically visible blanching did not occur. Ultrasound evaluation of skin thickness showed similar behaviour for all three steroids tested: there were no signs of skin atrophy in any of the cases. LDS evidenced hypoperfusion of a test area on the perfusion image in only a few patients and there were no significant differences between the steroids tested. On evaluation of vasoconstriction caused by the steroids tested using chromometry there was a significant difference between MF and OH-C on the L*a*b* scale (P<0.005). Only at day 3 was a blanching effect caused by MP and MF demonstrable (a-value, P<0.05).Conclusion In summary, the synthetic steroids MF and MP presented side-effects similar to those of OH-C but much greater vasoconstrictor effect; after an application period of over 5 days under occlusion a blanching effect in our model was not demonstrable by means of chromometry. Two-dimensional laser scanning offers no advantage in the evaluation of the blanching effect in comparison to one-dimensional laser fluxmetry (LDF).

The thalamus as a site of action of antipsychotic drugs

Because recent data suggest that there are abnormalities of the thalamus in schizophrenia, the authors tested the effects of antipsychotic drugs on thalamic sites. Nine rats were given acute doses of the typical neuroleptic haloperidol (N = 3), the atypical neuroleptic clozapine (N = 3), or a drug-free vehicle (N = 3). Cellular activation was assessed by using immunohistochemistry to determine expression of the immediate response gene c-fos. Both antipsychotic drugs induced increased Fos immunoreactivity, suggesting increased activity in cells of the midline nuclei of the thalamus. The shared clinical effects of antipsychotic drugs may be mediated in part through actions on the thalamus.