Topical nanocrystalline silver cream suppresses inflammatory cytokines and induces apoptosis of inflammatory cells in a murine model of allergic contact dermatitis.

BACKGROUND: Nanocrystalline silver has both antimicrobial and anti-inflammatory properties. However, the exact mechanisms underlying these activities are not known. OBJECTIVES: The objectives of this study were to assess the anti-inflammatory effects of nanocrystalline silver using a murine model of allergic contact dermatitis, compare the effects with those of tacrolimus and a high potency steroid, and to relate the effects to modulation of pro-inflammatory cytokines and apoptosis of inflammatory cells. METHODS: Dermatitis was induced on the ears of BALB/c mice using dinitrofluorobenzene. Topical treatment, including vehicles, 1% nanocrystalline silver cream, tacrolimus ointment and a high potency steroid, was applied once a day for 4 days. Ear swelling was measured and the erythema was evaluated daily. After 4 days of treatment the mice were killed and samples from the ears were collected for histological and immunohistochemical examination, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labelling (TUNEL) staining and extraction of total RNA for reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: Significant reductions of ear swelling, erythema and histopathological inflammation in mice ears were observed after 4 days of treatment with 1% nanocrystalline silver cream, tacrolimus ointment or a high potency steroid with no significant difference among them. Both RT-PCR and immunohistochemical staining of sections from ear biopsies demonstrated that nanocrystalline silver, tacrolimus and steroid significantly suppressed the expression of tumour necrosis factor (TNF)-alpha and interleukin (IL)-12. TUNEL staining demonstrated a significant increase in the numbers of apoptotic cells in material from the group treated with nanocrystalline silver when compared with that from groups treated with vehicle, tacrolimus or steroid. CONCLUSIONS: This study demonstrates that nanocrystalline silver inhibits allergic contact dermatitis in mice, similar to steroid and tacrolimus. Nanocrystalline silver suppresses the expression of TNF-alpha and IL-12 and induces apoptosis of inflammatory cells; mechanisms by which nanocrystalline silver may exert its anti-inflammatory effects.

Anti-inflammatory effect of topical nanocrystalline silver cream on allergic contact dermatitis in a guinea pig model.

The anti-inflammatory activity of topical nanocrystalline silver cream was assessed and compared with the effects of topical steroids and currently available immunosuppressants using a guinea pig model of allergic contact dermatitis. Dermatitis was induced with dinitrochlorobenzene and treated with different concentrations of nanocrystalline silver, medium and high potency steroids, tacrolimus and pimecrolimus, or appropriate vehicles once daily for 5 days. Erythema was evaluated daily (on a score of 0 to 4, from absent to very severe) and histopathology of the skin biopsies was evaluated after 5 days of treatment. Prior to treatment, the average scores of erythema in all the groups were in the range of 3(+) to 4(+). In the no treatment and vehicles groups these scores remained at about this level for the subsequent 5 days of the study. Nanocrystalline silver reduced erythema within 1 day of treatment in a concentration-dependent manner with significant reduction at silver concentrations of 0.5% and 1% (P < 0.05) and this reduction progressed throughout the study period. Steroids and immunosuppressants produced similar decreases in erythema, with no significant differences compared to 0.5% and 1% nanocrystalline silver. In skin biopsies scored for degree of inflammatory response, effects of treatments mirrored erythema results. This study suggests that nanocrystalline silver cream may have therapeutic potential for topical treatment of inflammatory skin diseases.

A double-blind, placebo-controlled, efficacy and safety study of topical gel formulation of 1% alprostadil (Topiglan) for the in-office treatment of erectile dysfunction.

OBJECTIVES: To asses the efficacy and safety of Topiglan (1% alprostadil in a formulation with 5% SEPA [soft enhancer of percutaneous absorption]) or placebo gel (0.25 mL) applied to the glans penis only in 60 patients with moderate to severe erectile dysfunction in a two-visit, in-office clinical trial. METHODS: During the first visit, open-label placebo gel was applied. At the second visit, blind, random allocation to Topiglan (n = 31) or placebo gel (n = 29) occurred. Thirty minutes after application, an erotic movie showing heterosexual sex began; at 45 minutes, a penile vibrator was used. Audiovisual and tactile stimulation were discontinued at 65 minutes, and the patient was observed until 90 minutes after application. At the scheduled time points, the erection response was assessed by both the investigator and the patient and signs and symptoms of tolerance were evaluated. RESULTS: Topiglan produced a greater angle of erection (P = 0.003) and maximum rigidity (P = 0.033) compared with the placebo gel. The responses to Topiglan were greater than to placebo gel at all time points after application, with the greatest differences observed at 45 and 60 minutes. Of the 31 patients treated with Topiglan, 12 (38.9%) achieved an erection judged sufficient for vaginal penetration (P = 0.005); 2 (6.9%) of the 29 patients who received placebo gel did so. Penile erythema was more common with Topiglan; symptoms of minor to mild warmth or burning and, less commonly, tingling and coolness were reported by most patients after both Topiglan and placebo gel application. No significant changes in vital signs were noted. CONCLUSIONS: Topiglan applied to the glans penis increased penile rigidity and expectations regarding vaginal penetration in patients with erectile dysfunction.

Pharmacokinetics and tolerability of intravenous trecovirsen (GEM 91), an antisense phosphorothioate oligonucleotide, in HIV-positive subjects.

Trecovirsen, a 25-mer antisense phosphorothioate oligonucleotide targeted at the gag site of the HIV gene, was administered to HIV-positive volunteers as an i.v. infusion. Single doses ranged from 0.1 to 2.5 mg/kg in an ascending escalation in cohorts of 6 to 12 subjects. Plasma trecovirsen concentrations and pharmacokinetic parameters could be assessed at doses > or = 0.3 mg/kg. Peak plasma concentrations and AUC values increased disproportionately with increasing dose while elimination half-life increased and plasma clearance decreased, indicating a saturable process over this dose range. The only significant adverse event observed was an isolated, transitory increase in activated partial thromboplastin time at doses > or = 2.0 mg/kg that was related to plasma trecovirsen concentrations and is attributed to the polyanionic character of the molecule. Thus, trecovirsen administration was well tolerated in single i.v. doses up to 2.5 mg/kg.

Complement activation and hemodynamic changes following intravenous administration of phosphorothioate oligonucleotides in the monkey.

Rapid intravenous infusion of GEM 91, a 25-mer phosphorothioate oligonucleotide complementary to the gag site of HIV, in the monkey produces transient decreases in peripheral total WBC and neutrophil counts, hemoconcentration, and a brief increase followed by a prolonged decrease in arterial blood pressure. These changes are preceded by and are likely mediated by activation of C5 complement. These effects are dose and infusion rate dependent and can be avoided by administering GEM 91 by slow intravenous infusion. Similar hemodynamic effects are produced with rapid intravenous infusion of other phosphorothioate oligonucleotides varying in length from 20- to 33-mer, and are, therefore, not sequence specific but a property of this chemical structure.

Clinical relevance of measuring GABA concentrations in cerebrospinal fluid.

Determination of GABA concentrations in human cerebrospinal fluid can be used to assess GABAergic activity in the central nervous system. As CSF free GABA concentrations may vary with age, sex, CSF fraction, and collection and storage conditions, careful attention to these factors are necessary to allow interpretation of results. Longitudinal studies to investigate the influence of pharmacological agents on CSF GABA have proven especially useful to define clinical biochemical activity and have been utilized to attribute the anti-epileptic action of vigabatrin, a selective inhibitor of GABA-transaminase, to its effects on brain GABA metabolism.

Review: Normal and abnormal central nervous system GABA metabolism in childhood.

The metabolism and function of central nervous system GABA is briefly reviewed. Hereditary disorders of the GABA metabolism presenting in childhood are discussed with particular emphasis on the recently identified succinic semialdehyde dehydrogenase deficiency and GABA-transaminase deficiency, and on diseases associated with low CSF GABA which await further unravelling. Low CSF GABA concentrations are not always associated with convulsions. A separate section is devoted to the CSF as a tool in the diagnosis of these disorders. Finally, we present a few diagnostic and therapeutic guidelines.

[African trypanosomiasis in children treated with eflornithine. A case]. / Trypanosomiase africaine de l'enfant traitée par éflornithine. Un cas.

We report the case of a 14-year old African girl presenting with late-stage African T. gambiense trypanosomiasis. She was treated with eflornithine, an ornithine decarboxylase inhibitor which is a key enzyme in the biosynthesis of polyamine. Polyamines are essential to the multiplication of trypanosomes. Two treatment courses were necessary to achieve an apparent cure after one year; however, a longer follow up will be required to confirm whether or not the cure is permanent. Determination of drug concentrations in plasma and cerebrospinal fluid was performed during the second treatment course. Side-effects were easily controlled.

[A trial treatment with eflornithine of trypanosomiasis caused by Trypanosoma brucei gambiense in the Peoples Republic of the Congo]. / Essai de traitement de la trypanosomiase à Trypanosoma brucei-gambiense par l'eflornithine en République Populaire du congo.

In a multiclinic trial in Brazzaville, Congo, 14 patients with late-stage Trypanosoma brucei gambiense trypanosomiasis were treated with eflornithine. All cases had previously been treated with one or several courses of melarsoprol. Eflornithine treatment consisted of 400 mg/kg/day intravenously for 14 days followed by 300 mg/kg/day orally for 21 days. After treatment all patients had a disappearance of trypanosomes from cerebrospinal fluid (CSF), a normalization of CSF WBC count, and, where present prior to study, a clear, rapid and lasting amelioration of neurological signs. Neither clinical nor biological adverse effects necessitated modifying or discontinuing treatment. These encouraging results in melarsoprol-refractory cases demonstrate, despite certain logistical problems, the interest of eflornithine in the treatment of human African trypanosomiasis.

Cerebrospinal fluid parameters in healthy volunteers during serial lumbar punctures.

Lumbar punctures were performed on four occasions over a 5-day period (8:30 a.m. on days 1, 3, and 5; 2:30 p.m. on day 2) on 10 normal volunteers (five of each sex; mean age, 27.7 years) to assess, with repeated sampling, the day-to-day variation of selected CSF parameters. Two subjects abstained from the lumbar puncture on day 5 due to headache after the third puncture. Lumbar CSF was analyzed for concentrations of free and total gamma-aminobutyric acid (GABA), homocarnosine, homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), total protein, albumin, and immunoglobulin (Ig)G. No significant concentration differences were found between the afternoon and next morning samples. No differences were found in concentrations of free GABA, total GABA, homocarnosine, 5-HIAA, or albumin across the study. In contrast, HVA concentrations significantly increased by day 5, whereas total protein and IgG decreased during the study. The most likely explanation for these changes involves the known concentration gradients in the CSF column.

The effect of different vigabatrin treatment regimens on CSF biochemistry and seizure control in epileptic patients.

1. Vigabatrin, 50 mg kg-1, was administered orally as add-on therapy to 11 patients with drug-resistant complex partial epilepsy as a single dose, then once every third day for 2 months, every other day for 2 months and daily for 1 month. 2. Lumbar punctures were carried out prior to treatment and at the end of each dosage regimen and cerebrospinal fluid (CSF) evaluated for concentrations of free and total GABA, homocarnosine (GABA-histidine dipeptide), homovanillic acid (HVA), 5-hydroxyindole acetic acid (5-HIAA) and vigabatrin. 3. Each regimen resulted in significant increases in CSF concentrations of free and total GABA and homocarnosine compared with the immediately preceding regimen. 4. CSF concentrations of HVA significantly increased after a single vigabatrin dose but returned to pre-treatment levels with subsequent dosing schedules. In contrast, 5-HIAA concentrations also increased with the single dose but were significantly decreased, compared with pre-treatment values, following alternate day and daily vigabatrin administration. 5. Seizure frequency progressively decreased with decreasing dosing interval. Daily vigabatrin administration was associated with greater than 50% decrease in seizures in 8 of the 10 patients treated.

[The use of difluoromethylornithine in congenital trypanosomiasis due to Trypanosoma brucei-gambiense]. / Utilisation de la difluorométhylornithine dans la trypanosomiase congénitale à Trypanosoma brucei-gambiense.

The authors describe their experience with two cases of congenital Trypanosoma brucei-gambiense trypanosomiasis treated with orally administered difluoromethylornithine. The first case tolerated well his treatment (35 days of DFMO) and has probably been definitively cured. The second case, already in a desperate condition upon admission, died after only 4 days of difluoromethylornithine (DFMO). The authors hypothesize that difluoromethylornithine (DFMO) may be the drug of choice for congenital trypanosomiasis because of its good absorption by the oral route, its ability to penetrate the cerebrospinal fluid especially in presence of meningeal inflammation and its activity against Trypanosoma brucei-gambiense.

Clinical pharmacology of vigabatrin.

1. Upon oral administration vigabatrin is rapidly absorbed. Plasma elimination half-life ranges between 5 and 7 h in normal volunteers. Vigabatrin is eliminated primarily via the kidneys with about 65% of the administered dose found unchanged in the urine within 24 h. Kinetics are dose-linear within the range of usual therapeutic doses. 2. At therapeutic doses in man vigabatrin produces dose-related increases in CSF concentrations of free and total GABA, homocarnosine (the GABA-histidine dipeptide) and beta-alanine. These biochemical changes are consistent with an inhibition of GABA-transaminase activity in brain. 3. Thus, with systemic availability upon oral administration and biochemical activity in the CNS, the prerequisites for potential uses of vigabatrin in neurological disorders have been demonstrated in clinical pharmacological studies.

Pharmacokinetics of vigabatrin: implications of creatinine clearance.

The pharmacokinetics of both enantiomers of vigabatrin after a single oral dose in healthy young subjects (mean creatinine clearance 120 ml/min) were compared with kinetics in two groups of elderly subjects, one group aged 60 to 75 years (mean creatinine clearance 86 ml/min) and one group aged 76 to 97 years (mean creatinine clearance 30 ml/min). At a dose of 1500 mg, the group with the eldest subjects and the lowest creatinine clearance values showed mean increases of 3.3-fold in the time to reach the maximum concentration, 2.7-fold in the maximum concentration, and 9.8-fold in the AUC; a twofold prolongation of the t1/2; and reduced urinary excretion of the biologically and pharmacologically active S(+)-enantiomer. Changes in the intermediate group were qualitatively similar but quantitatively less. Parallel observations were made for the inactive R(-)-enantiomer. Most of these changes can be related to decreased renal clearance of vigabatrin. No interference of either enantiomer in the renal clearance of the other was noted. A nonlinear relationship between renal clearance and creatinine clearance for both enantiomers is suggested. Knowledge of the patient's renal function and an appropriate dose adjustment will minimize side effects during vigabatrin therapy, especially in elderly patients.

Effects of single doses of vigabatrin on CSF concentrations of GABA, homocarnosine, homovanillic acid and 5-hydroxyindoleacetic acid in patients with complex partial epilepsy.

Vigabatrin, as a single oral dose of 50 mg/kg, was administered to 11 patients with drug-refractory complex partial epilepsy. Serial lumbar punctures were performed prior to and 5 times within the first week following treatment. Cerebrospinal fluid (CSF) concentrations of total GABA, free GABA, homocarnosine, homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA) and vigabatrin were determined as well as blood vigabatrin levels. CSF GABA, homocarnosine, HVA and 5-HIAA concentrations increased by 6 h after the single dose and remained elevated for up to 5-7 days. In contrast, CSF and blood vigabatrin levels were maximal within the first 24 h and were no longer detectable thereafter. Hence, these results are consistent with vigabatrin acting as an irreversible inhibitor of GABA-transaminase and suggest that it may also increase biogenic amine turnover.

Design and early clinical evaluation of selective inhibitors of monoamine oxidase.

1. Selective inhibitors of the monoamine oxidase (MAO) isoenzymes, types A and B, are of potential therapeutic utility. Brain selectivity would overcome the risk of tyramine interactions which have been shown to occur with selective MAO-A but not MAO-B inhibitors. 2. (E)-3-Fluoroallylamines of general structure, FHC = C(R)CH2NH2 have been designed as enzyme-activated, irreversible inhibitors of these enzymes. Two compounds, MDL 72145 (R = 3,4 dimethoxyphenyl) and MDL 72974 (R = 4-fluorophenethyl), are selective and irreversible inhibitors of MAO type B which in vivo show high inhibitory potency against the rat brain enzyme (ED50 0.35 and 0.18 mg/kg p.o., respectively). In animals, these inhibitors do not potentiate the cardiovascular effects of tyramine and have no amphetamine-like effects. However, they do potentiate the central effects of L-Dopa and prevent the neurotoxic effects of MPTP in both mice and monkeys. 3. In early clinical studies, MDL 72145 has been shown to be a potent, long-acting inhibitor of MAO type B. Doses of 16 mg per patient totally inhibit platelet enzyme without potentiating the cardiovascular effects of oral tyramine. Compounds of this type should prove useful in Parkinson's disease. 4. Selective inhibition of brain MAO-A can be achieved by using the bioprecursor amino acid MDL 72394 (E-beta-fluoromethylene-m-tyrosine). This amino acid is decarboxylated by aromatic L-amino acid decarboxylase (AADC) to liberate MDL 72392 (R = 3-hydroxyphenyl), a potent irreversible inhibitor of MAO-A. Combination of MDL 72394 with a peripherally selective inhibitor of AADC (e.g., carbidopa) restricts MAO inhibition to the brain. Consequently, under these conditions, there is a greatly reduced propensity to potentiate the cardiovascular effects of tyramine. 5. This has been confirmed in human volunteers; MDL 72394 (8 mg), combined with carbidopa, substantially decreased urinary MHPG and plasma DHPG concentrations with minimal potentiation of the cardiovascular effects of i.v. tyramine. These results predict that such therapy has potential in the treatment of affective disorders.

[Treatment of human trypanosomiasis caused by Trypanosoma brucei gambiense using alpha-difluoromethylornithine. Results in 7 patients]. / Traitement de la trypanosomiase humaine à Trypanosoma brucei gambiense par l'alpha-difluorométhylornithine. Résultats chez 7 patients.

Alpha-difluoromethylornithine (DFMO, eflornithine) is a specific irreversible inhibitor of ornithine decarboxylase, shown to be curative in various Trypanosoma species infections of animals. In the present open study, the efficiency of DFMO was assessed in 7 patients (4 Africans, 3 Europeans) with Trypanosoma brucei gambiense (Tbg) infection, 4 in the advanced stage and 3 in the early phase of the disease. Treatment with DFMO at initial dosages ranging 300-500 mg/kg/day administered IV (except 1 case) for 10-15 days, followed by 200-300 mg/kg/day per os for 28-69 days was associated with clearing of trypanosomes from blood within 1-4 days, a trend towards normalisation or full normalisation of all altered biological values characterizing the disease and disappearance of clinical symptoms. Side effects of DFMO, including loose stools (5 cases), anemia (3 cases) and decreased hearing (1 case), were mild and transient requiring no treatment or interruption of the drug, except in one case. Pharmacokinetic studies carried out in 4 patients, demonstrate penetration of the drug into CNS. In 6 cases, no evidence of relapse was found at 24 months posttreatment follow-up indicating that DFMO can be curative in early and late-stage of Tbg sleeping sickness. In 1 case, no relapse could be detected after a follow-up of 6 months. Further studies are needed to confirm our encouraging results and to determine the optimal regimens of DFMO for the cure of the early and late-stage of sleeping sickness.

Difluoromethylornithine for arseno-resistant Trypanosoma brucei gambiense sleeping sickness.

26 patients with arseno-resistant Trypanosoma brucei gambiense trypanosomiasis were treated with difluoromethylornithine (eflornithine), an inhibitor of ornithine decarboxylase, given intravenously, then orally. There was rapid disappearance of trypanosomes in the cerebrospinal fluid (CSF), gradual decrease of CSF lymphocytosis, and parallel improvement in central nervous system status. Side-effects, including diarrhoea, anaemia, and hair loss, were common but tolerable and reversible. 5 patients died during or shortly after treatment. None of the 21 patients who completed therapy has had a relapse during the 6-30 month follow-up.

2-Pyrrolidinone in human cerebrospinal fluid: a major constituent of total gamma-aminobutyric acid.

2-Pyrrolidinone, the lactam of gamma-aminobutyric acid (GABA), is identified as the major constituent of total GABA in human CSF. Structural elucidation was done by mass spectrometry. In lumbar CSF of four patients, 2-pyrrolidinone represented about 54% of GABA found after acid hydrolysis, thus accounting for essentially all of the hitherto unknown GABA fraction in CSF.