Effect of antibiotics on the generation of reactive oxygen species

Two randomized phase III clinical trials evaluating anti-inflammatory dose doxycycline (40-mg doxycycline, USP capsules) administered once daily for treatment of rosacea

BACKGROUND

Doxycycline monotherapy at antimicrobial doses has been shown to be effective for the treatment of rosacea.

OBJECTIVE

To evaluate the efficacy and safety of once-daily anti-inflammatory dose doxycycline for the treatment of rosacea.

METHODS

In two phase III, parallel-group, multicenter, randomized, double-blind, placebo-controlled studies (studies 301 and 302), patients received 40-mg of controlled-release doxycycline (n = 269) or placebo (n = 268) for 16 weeks. The primary efficacy end point was the mean change from baseline in facial inflammatory lesion count.

RESULTS

The mean lesion count at baseline was approximately 20 in each study arm. At week 16, the mean change from baseline in lesion count in the active-treatment groups was -11.8 in study 301 and -9.5 in study 302 compared with -5.9 and -4.3, respectively, in the placebo groups (P < .001 for both comparisons). Anti-inflammatory dose doxycycline was well tolerated; the most common adverse events were nasopharyngitis (4.8%), diarrhea (4.4%), and headache (4.4%).

LIMITATIONS

In both studies, the reduction of inflammatory lesion counts did not plateau within the 16-week time frame in either treatment group. Rosacea is often treated for a period of months or years. The duration of the studies did not allow for assessment of safety beyond 16 weeks or whether the progressive improvement seen with active treatment would continue beyond 16 weeks. Neither study assessed the effect of treatment in patients with only erythematotelangiectatic (subtype 1) rosacea.

CONCLUSION

Once-daily anti-inflammatory dose doxycycline appears to be effective and safe for the treatment of rosacea.

The effect of azithromycin on reactive oxygen species in rosacea

BACKGROUND

Recent evidence suggests that inflammation in rosacea is associated with generation of reactive oxygen species (ROS) that are released by inflammatory cells. The efficacy of current therapeutic agents for rosacea such as tetracyclines and metronidazole has also been attributed to their antioxidant properties. Recently, a macrolide antibiotic, azithromycin, has been found to be an effective alternative in the treatment of rosacea.

AIM

We planned a study to evaluate the antioxidant effects of azithromycin on ROS in rosacea. We compared basal ROS concentrations measured in the facial skin of patients with rosacea with the post-treatment levels and with those of healthy controls.

METHODS

Facial skin biopsies of 17 papulopustular patients with rosacea and 25 healthy controls were taken. Rosacea patients were assigned to receive oral azithromycin 500 mg on three consecutive days each week for 4 weeks. The total number of inflammatory lesions (the sum of papules and pustules) on the face of each patient with rosacea was counted at each visit. The luminol- and lucigenin-enhanced chemiluminescence (CL) levels of patients with rosacea were measured before and after 4 weeks of treatment and compared with those of healthy controls.

RESULTS

Rosacea patients had higher ROS levels than healthy controls (P < 0.001). A statistically significant decrease of both luminol- and lucigenin-enhanced CL levels were observed in patients with rosacea after treatment with azithromycin (t = 4.602, P < 0.001; vs. t = 4.634, P < 0.001, respectively).

CONCLUSION

Rosacea patients have higher ROS levels than healthy controls. The results of our study support the antioxidant properties of azithromycin in rosacea.

Reactive oxygen and nitrogen species: Implications for cardiovascular device engineering

The development of medical devices for cardiovascular applications has suffered due to lack of understanding of why vascular wall cells act nonphysiologically when exposed to biomaterials. One possible reason might be the chemical environment associated with cardiovascular disease. An improved understanding of cellular and subcellular mechanisms may assist in future device design to account for the disease environment. Reactive oxygen and nitrogen species (ROS/RNS) are produced through normal cellular metabolism and are rendered harmless by enzymatic systems. However, during a disease process, these systems may act aberrantly, and either fail to convert ROS and RNS to harmless substances or by producing more oxidants. There is indirect evidence that the implantation of biomedical materials may also be responsible for the triggering of these aberrant pathways that may lead to the eventual failure of the device. The understanding of how the vascular environment may be changed at the subcellular level by the presence of a biomaterial is critical. In the following pages, we hope to review the current thinking within vascular biology regarding ROS and RNS, how they are measured, and how they may impact vascular cells.

Paraquat-induced Oxidative Stress in Drosophila melanogaster: Effects of Melatonin, Glutathione, Serotonin, Minocycline, Lipoic Acid and Ascorbic Acid

The efficacy of melatonin, glutathione, serotonin, minocycline, lipoic acid and ascorbic acid in counteracting the toxicity of paraquat in Drosophila melanogaster was examined. Male Oregon wild strain flies were fed for 5 days with control food or food containing the test substance. They were transferred in groups of five to vials containing only filter paper soaked with 20 mM paraquat in 5% sucrose solution. Survival was determined 24 and 48 h later. All the substances assayed increased the survival of D. melanogaster. At equimolar concentrations (0.43 mM) melatonin was more effective than serotonin, lipoic acid and ascorbic acid. However, lower concentrations of glutathione (0.22 mM) and minocycline (0.05 mM) were as efficient as melatonin. The highest survival rate (38.6%) after 48 h of paraquat treatment was found with 2.15 mM of lipoic acid. No synergistic effect of melatonin with glutathione, serotonin, minocycline, lipoic acid and ascorbic acid was detected.

Anti-amyloidogenic effects of antioxidants: Implications for the prevention and therapeutics of Alzheimer's disease

Alzheimer's disease (AD) is one of the most common dementing disorders and has profound medical and social consequences. The initiating molecular event is unknown, and its pathophysiology is highly complex. However, free radical injury appears to be a fundamental process contributing to the neuronal death seen in this disorder, and many studies using surrogate markers of oxidative damage have provided evidence supporting this hypothesis. Various compounds with antioxidant ability attenuated the oxidative stress induced by amyloid beta-protein (Abeta) in studies done in vitro and in vivo. Moreover, various antioxidants have been reported to inhibit the formation and extension of beta-amyloid fibrils (fAbeta), as well as to destabilize preformed fAbeta in vitro. In cell culture experiments, destabilized fAbeta were suggested to be less toxic than intact fAbeta. In transgenic mice model studies, some antioxidant compounds reduced plaque burden in vivo. In this article, we review the recent advances in the research on the antioxidants that inhibit the formation of fAbeta, as well as destabilize preformed fAbeta. Although the mechanisms by which these compounds inhibit fAbeta formation from Abeta, and destabilize preformed fAbeta are still unclear, they could be key molecules for the development of preventives and therapeutics for AD.

Antioxidant compounds have potent anti-fibrillogenic and fibril-destabilizing effects for alpha-synuclein fibrils in vitro

The aggregation of alpha-synuclein (alphaS) in the brain has been implicated as a critical step in the development of Lewy body diseases (LBD) and multiple system atrophy (MSA). Various antioxidants not only inhibit the formation of beta-amyloid fibrils (fAbeta), but also destabilize preformed fAb in vitro. Using fluorescence spectroscopy with thioflavin S and electron microscopy, here we examined the effects of the antioxidants nordihydroguaiaretic acid, curcumin, rosmarinic acid, ferulic acid, wine-related polyphenols [tannic acid, myricetin, kaempferol (+)-catechin and (-)-epicatechin], docosahexaenoic acid, eicosapentaenoic acid, rifampicin and tetracycline on the formation of alphaS fibrils (falphaS) and on preformed falphaS. All molecules, except for docosahexaenoic acid and eicosapentaenoic acid, dose-dependently inhibited the formation of falphaS. Moreover, these molecules dose-dependently destabilized preformed falphaS. The overall activity of the molecules examined was in the order of: tannic acid=nordihydroguaiaretic acid=curcumin=rosmarinic acid=myricetin>kaempferol=ferulic acid>(+)-catechin=(-)-epicatechin>rifampicin=tetracycline. These compounds with anti-fibrillogenic as well as antioxidant activities could be key molecules for the development of preventives and therapeutics for LBD and MSA as well as Alzheimer's disease.

Alpha-lipoic acid exhibits anti-amyloidogenicity for beta-amyloid fibrils in vitro

Inhibition of the formation of beta-amyloid fibrils (fAbeta), as well as the destabilization of preformed fAbeta in the CNS would be attractive therapeutic targets for the treatment of Alzheimer's disease (AD). Using fluorescence spectroscopic analysis with thioflavin T and electron microscopic studies, we examined the effects of alpha-lipoic acid (LA) and the metabolic product of LA, dihydrolipoic acid (DHLA), on the formation, extension, and destabilization of fAbeta at pH 7.5 at 37 degrees C in vitro. LA and DHLA dose-dependently inhibited fAbeta formation from amyloid beta-protein, as well as their extension. Moreover, they destabilized preformed fAbetas. LA and DHLA could be key molecules for the development of therapeutics for AD.

Minocycline fails to protect cerebellar granular cell cultures against malonate-induced cell death

Experimental and clinical studies support the view that the semisynthetic tetracycline minocycline exhibits neuroprotective roles in several models of neurodegenerative diseases, including ischemia, Huntington, Parkinson diseases, and amyotrophic lateral sclerosis. However, recent evidence indicates that minocycline does not always present beneficial actions. For instance, in an in vivo model of Huntington's disease, it fails to afford protection after malonate intrastriatal injection. Moreover, it reverses the neuroprotective effect of creatine in nigrostriatal dopaminergic neurons. This apparent contradiction prompted us to analyze the effect of this antibiotic on malonate-induced cell death. We show that, in rat cerebellar granular cells, the succinate dehydrogenase inhibitor malonate induces cell death in a concentration-dependent manner. By using DFCA, monochlorobimane and 10-N-nonyl-Acridin Orange to measure, respectively, H2O2-derived oxidant species and reduced forms of GSH and cardiolipin, we observed that malonate induced reactive oxygen species (ROS) production to an extent that surpasses the antioxidant defense capacity of the cells, resulting in GSH depletion and cardiolipin oxidation. The pre-treatment for 4 h with minocycline (10-100 microM) did not present cytoprotective actions. Moreover, minocycline failed to block ROS production and to abrogate malonate-induced oxidation of GSH and cardiolipin. Additional experiments revealed that minocycline was also unsuccessful to prevent the mitochondrial swelling induced by malonate. Furthermore, malonate did not induce the expression of the iNOS, caspase-3, -8, and -9 genes which have been shown to be up-regulated in several models where minocycline resulted cytoprotective. In addition, malonate-induced down-regulation of the antiapoptotic gene Bcl-2 was not prevented by minocycline, controversially the mechanism previously proposed to explain minocycline protective action. These results suggest that the minocycline protection observed in several neurodegenerative disease models is selective, since it is absent from cultured cerebellar granular cells challenged with malonate.

Tropical sprue

Tropical sprue (TS) is a clinical entity of unknown etiology characterized by an acquired chronic diarrheal illness and malabsorption that affects indigenous inhabitants and expatriates, either long-term residents or short-term visitors, in the tropical countries. The exact pathogenetic sequence of TS remains incompletely characterized. Bacterial overgrowth, disturbed gut motility, and hormonal and histopathologic abnormalities contribute to the development of TS in a susceptible host. Treatment with tetracycline and folate is effective in some patients, although relapses after treatment are common. Research in the areas of microbial factors, pathogenesis, immunogenetics, and hormonal and immune regulation, using modern diagnostic techniques, may be able to settle some of the unanswered issues and open new venues for diagnosis, prevention, and treatment of tropical sprue.

Antioxidant properties of minocycline: neuroprotection in an oxidative stress assay and direct radical-scavenging activity

Minocycline is neuroprotective in animal models of a number of acute CNS injuries and neurodegenerative diseases. While anti-inflammatory and anti-apoptotic effects of minocycline have been characterized, the molecular basis for the neuroprotective effects of minocycline remains unclear. We report here that minocycline and a number of antioxidant compounds protect mixed neuronal cultures in an oxidative stress assay. To evaluate the role of minocycline's direct antioxidant properties in neuroprotection, we determined potencies for minocycline, other tetracycline antibiotics, and reference antioxidant compounds using a panel of in vitro radical scavenging assays. Data from in vitro rat brain homogenate lipid peroxidation and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays show that minocycline, in contrast to tetracycline, is an effective antioxidant with radical scavenging potency similar to vitamin E. Our findings suggest that the direct antioxidant activity of minocycline may contribute to its neuroprotective effects in some cell-based assays and animal models of neuronal injury.

Neuroprotective effects of minocycline against in vitro and in vivo retinal ganglion cell damage

The purpose of this study was to determine whether minocycline, a semi-synthetic tetracycline derivative, reduces (a) the in vitro neuronal damage occurring after serum deprivation in cultured retinal ganglion cells (RGC-5, a rat ganglion cell line transformed using E1A virus) and/or (b) the in vivo retinal damage induced by N-methyl-D-aspartate (NMDA) intravitreal injection in mice. In addition, we examined minocycline's putative mechanisms of action against oxidative stress and endoplasmic reticulum (ER) stress. In vitro, retinal damage was induced by 24-h serum deprivation, and cell viability was measured by Hoechst 33342 staining or resazurin reduction assay. In cultures of RGC-5 cells maintained in serum-free medium for up to 24 h, the number of cells undergoing cell death was reduced by minocycline (0.2-20 microM). Serum deprivation resulted in increased oxidative stress, as revealed by an increase in the fluorescence intensity for 5-(and-6)-chloromethyl-2', 7'-dichlorodihydrofluorescein diacetate (CM-H2DCFDA), a reactive oxygen species (ROS) indicator. Minocycline at 2 and 20 microM inhibited this ROS production. However, even at 20 microM minocycline did not inhibit the retinal damage induced by tunicamycin (an ER stress inducer). Furthermore, in mice in vivo minocycline at 90 mg/kg intraperitoneally administered 60 min before an NMDA intravitreal injection reduced the NMDA-induced retinal damage. These findings indicate that minocycline has neuroprotective effects against in vitro and in vivo retinal damage, and that an inhibitory effect on ROS production may contribute to the underlying mechanisms.

Minocycline partially inhibits caspase-3 activation and photoreceptor degeneration after photic injury

PURPOSE

To evaluate the possible role of caspase-3 in retinal photic injury, and to investigate whether minocycline can ameliorate light-induced photoreceptor degeneration.

METHODS

Retinal photic injury was induced in rats by exposure to intense light. Expression of caspase-3 was studied using Western blot analysis, immunohistochemical staining and enzyme activity assay. Apoptotic photoreceptor cells were detected by the TdT-dUTP terminal nick-end labeling (TUNEL) method. Minocycline (15, 30 or 45 mg/kg) was administered before or after photic injury in rats randomly assigned to pretreatment and posttreatment groups. Minocycline and vehicle-treated retinas subjected to photic injury were compared with respect to Western blotting, enzyme activity assay, quantitative counts of TUNEL stains, morphometry of the outer nuclear layer (ONL) thickness and histopathological examination.

RESULTS

After light exposure, active caspase-3 and poly-adenosine diphosphate-ribose-polymerase were upregulated in the retinas and increased caspase-3 immunoreactivity was observed in the ONL. Caspase-3 enzyme activity increased in the retinas that underwent photic injury, and this increase was significantly reduced in minocycline pretreated (30 and 45 mg/kg) and posttreated (45 mg/kg) groups. Intraperitoneal administration of minocycline before or after photic injury in rats also resulted in less TUNEL-positive photoreceptors, as assessed by the quantitative TUNEL counts. The degree of retinal degeneration, measured by the ONL thickness 14 days after photic injury, was significantly improved in minocycline pretreatment (45 mg/kg) rats.

CONCLUSIONS

We demonstrate that increased caspase-3 activities localize specifically within the ONL after photic injury, and that minocycline partially inhibits caspase-3 activation and photoreceptor degeneration in this animal model.

Effects of minocycline on Fas-mediated fulminant hepatitis in mice

1. Minocycline has anti-inflammatory and antiapoptotic effects on cartilage, neurons and periodontal tissues, and both properties are central to the pharmaceutical treatment of liver diseases. We investigated the effects of minocycline on fulminant hepatitis in C57BL/6J mice induced by lethal challenge of the activating anti-Fas antibody, Jo2. 2. Intraperitoneal injection of Jo2 (0.6 microg g(-1)) to mice resulted in fulminant hepatitis, as evidenced by increase of serum alanine/aspartate transaminase activities and histopathological alterations in liver sections, as well as animal death. Nevertheless, mice pretreated with three doses of minocycline (5 mg kg(-1)) resisted this lethal effect significantly. Minocycline treatment improved the survival kinetics, although to a lesser extent, when mice were challenged simultaneously with Jo2 or even treated 30 min after the lethal challenge. 3. Jo2-induced activation of caspase-3 or -9 in liver tissues was inhibited by minocycline pretreatment, and yet the direct addition of minocycline to liver extracts from Jo2-challenged mice failed to block caspase activation in vitro. Moreover, minocycline efficiently suppressed the release of cytochrome c from mitochondria of the liver tissues from Jo2-challenged mice. In contrast, caspase-8 activation and Bid truncation triggered by Jo2 were not diminished by minocycline pretreatment in mouse livers. 4. Our results suggest that easing of Fas-triggered fulminant hepatitis by minocycline may involve a mitochondrial apoptotic pathway, probably through preventing cytochrome c release and thereby blocking downstream caspase activation.

Minocycline inhibits oxidative stress and decreases in vitro and in vivo ischemic neuronal damage

The neuroprotective effects of minocycline-which is broadly protective in neurologic-disease models featuring cell death and is being evaluated in clinical trials-were investigated both in vitro and in vivo. For the in vivo study, focal cerebral ischemia was induced by permanent middle cerebral artery occlusion in mice. Minocycline at 90 mg/kg intraperitoneally administered 60 min before or 30 min after (but not 4 h after) the occlusion reduced infarction, brain swelling, and neurologic deficits at 24 h after the occlusion. For the in vitro studies, we used cortical-neuron cultures from rat fetuses in which neurotoxicity was induced by 24-h exposure to 500 microM glutamate. Furthermore, the effects of minocycline on oxidative stress [such as lipid peroxidation in mouse forebrain homogenates and free radical-scavenging activity against diphenyl-p-picrylhydrazyl (DPPH)] were evaluated to clarify the underlying mechanism. Minocycline significantly inhibited glutamate-induced cell death at 2 microM and lipid peroxidation and free radical scavenging at 0.2 and 2 microM, respectively. These findings indicate that minocycline has neuroprotective effects in vivo against permanent focal cerebral ischemia and in vitro against glutamate-induced cell death and that an inhibition of oxidative stress by minocycline may be partly responsible for these effects.

The Contribution of Meibomian Disease to Dry Eye

The tear film lipid layer is the major barrier to evaporation from the ocular surface. A decrease in its thickness or functional integrity may cause evaporative dry eye (EDE). Obstructive meibomian gland dysfunction (MGD) is the most common cause of EDE and occurs as a primary disorder or secondary to acne rosacea, seborrheic or atopic dermatitis, and with cicatrizing conjunctival disorders, such as trachoma, erythema multiforme, and cicatricial pemphigoid. MGD may be an incidental finding in asymptomatic eyes, or it may be responsible for irritative lid symptoms in the absence of dry eye. MGD-dependent EDE is diagnosed on the basis of a defined degree of MGD in a symptomatic patient showing typical ocular surface damage in the absence of an aqueous tear deficiency. When MGD occurs in a background of aqueous tear deficiency (ATD), then an additional evaporative component may assumed, depending on the extent of meibomian obstruction. However, definitive criteria are not yet established. The clinical severity of dry eye is greatest when ATD and EDE occur together, particularly in Sjogren syndrome. A hypothesis is proposed to explain the steps leading to primary, simple MGD and subsequent EDE.

Roxithromycin decreases ultraviolet B irradiation-induced reactive oxygen intermediates production and apoptosis of keratinocytes

BACKGROUND

In addition to their antimicrobial action, roxithromycin (RXM), a new 14-membrane macrolide antibiotics, have immunomodulatory, anti-inflammatory and anti-oxidative activity. Ultraviolet B (UVB) irradiation induces reactive oxygen intermediates and apoptosis of keratinocytes.

OBJECTIVE

To examine the anti-apoptotic and anti-oxidative effect of RXM on UVB-irradiated keratinocytes.

METHODS

UVB-induced apoptosis was determined by cell death assay using crystal violet staining, and DNA fragmentation assay. Superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), and calatase activities were measured in UVB-irradiated SV40-trasnformed human keratinocytes (SVHK cells). Detection of superoxide was performed histologically using hydroethidine and colorimetric quantitative assay using ferrous irons. H(2)O(2) was measured by colorimetrical assay.

RESULTS

RXM suppressed UVB-induced apoptosis of SVHK cells. UVB-irradiated SVHK cells showed decreased SOD, GPx, GR, and catalase activities. RXM pretreatment suppressed the decrease in these enzyme activities with the maximal effect detected at 10microM of RXM. The effect was associated with suppression of UVB-induced superoxide and H(2)O(2) production.

CONCLUSION

The present study demonstrated that RXM has anti-apoptotic and anti-oxidative effects against UVB-irradiated keratinocytes.

Macrolide antibiotics inhibit prostaglandin E2 synthesis and mRNA expression of prostaglandin synthetic enzymes in human leukocytes

We investigated the action of macrolide antibiotics, which are considered to have anti-inflammatory activity, on lipopolysaccharide (LPS)-stimulated prostaglandin (PG) E2 synthesis and the expression of mRNAs for cytosolic phospholipase A2 (cPLA2), cyclooxygenase (COX)-1, and COX-2 in human leukocytes. The production of LPS-stimulated PGE2 was significantly increased in peripheral polymorphonuclear leukocytes (PMNLs) and in mononuclear leukocytes (MNLs). Amounts of mRNAs for COX-2 and cPLA2, but not for COX-1, were enhanced by LPS in PMNLs and MNLs. The LPS-enhanced PGE2 synthesis and the expression of cPLA2 and COX-2 mRNAs were inhibited by clarithromycin, azithromycin and dexamethasone in PMNLs and MNLs. The mRNA expression of COX-1 in PMNLs was decreased by clarithromycin and azithromycin. Macrolide antibiotics inhibited PGE2 synthesis in human leukocytes by suppressing cPLA2, COX-1, and COX-2 mRNA expression. These data indicate one mechanism of macrolide anti-inflammatory activity.

The rationale for using a topical retinoid for inflammatory acne

Both comedogenesis and the development of inflammatory lesions in acne vulgaris appear to be related to genetic as well as immune processes. The key regulatory cytokine, interleukin-1alpha, has recently been documented as playing a major role in both the hypercornification and the orchestration of immune factors, ultimately resulting in noninflammatory and inflammatory lesions. Topical retinoids, such as tretinoin, and topical retinoid analogs, such as adapalene and tazarotene, help normalize the abnormal follicular keratinocyte desquamation - a key pathophysiologic factor in comedogenesis. This normalization also helps mitigate against the development of a propitious microenvironment for Propionibacterium acnes. Preclinical data suggest that topical retinoids and retinoid analogs may also have direct anti-inflammatory effects. A wealth of clinical data confirms that topical retinoids and retinoid analogs significantly reduce inflammatory lesions. Comparative clinical trials also demonstrate that adapalene has the best cutaneous tolerability profile of all these agents. Optimal therapy for inflammatory acne would involve the use of topical retinoids or retinoid analogs combined with oral or topical antibacterials.

Increased hydrogen peroxide generation by neutrophils from patients with acne inflammation

BACKGROUND

Reactive oxygen species generated by neutrophils are closely correlated with the pathogenesis of a variety of inflammatory skin diseases. The aim of this study was to investigate the possible role of reactive oxygen species generated by neutrophils in the mediation of acne inflammation.

METHODS

Bacterial phagocytotic stimuli, mediated by opsonin activity, were applied to whole blood, and neutrophil hydrogen peroxide production was measured.

RESULTS

Patients with acne inflammation showed a significantly increased level of hydrogen peroxide produced by neutrophils compared to patients with acne comedones and healthy controls. There were no marked differences in the level of hydrogen peroxide produced by neutrophils between patients with acne comedones and healthy controls. In addition, patients with acne inflammation treated by oral administration of minocycline hydrochloride, a drug that inhibits hydrogen peroxide generation by neutrophils, showed a significant decrease in the ability of neutrophils to produce hydrogen peroxide in accordance with a decrease in the inflammatory activity of acne lesions.

CONCLUSIONS

The present study seems to suggest that acne inflammation is mediated in part by hydrogen peroxide generation by neutrophils.

Lupoid sycosis of pubic area

Lupoid sycosis is a rare cicatricial form of chronic folliculitis commonly seen in men after puberty. It usually involves the beard area and is refractory to treatment. We here report two cases of lupoid sycosis; one had additional involvement of the pubic area. Both patients showed complete clearance with minocycline.

Minocycline blocks 6-hydroxydopamine-induced neurotoxicity and free radical production in rat cerebellar granule neurons

Neurotoxicity induced by 6-hydroxydopamine (6-OHDA) is believed to be due, in part, to the production of reactive oxygen species (ROS). Anti-oxidants by inhibiting free radical generation, protect neurons against 6-OHDA-induced neurotoxicity. In this study, we investigated whether or not minocycline, a neuroprotective compound, could directly protect neurons against 6-OHDA-induced neurotoxicity and inhibit 6-OHDA-induced free radical production in cultured rat cerebellar granule neurons (CGN). We now report that exposure of CGN to 6-OHDA (100 microM) resulted in a significant increase in free radical production with death of 86% of CGN. Pretreatment with minocycline (10 microM) for 2 h prevented 6-OHDA-induced free radical generation and neurotoxicity. Furthermore, minocycline also attenuated H(2)O(2)-induced neurotoxicity. Our results suggest that minocycline blocks 6-OHDA-induced neuronal death possibly by inhibiting 6-OHDA-induced free radical generation in CGN. Both the antioxidative and neuroprotective effects of minocycline may be beneficial in the therapy of Parkinson's disease and other neurodegenerative diseases.

Tissue reparative effects of macrolide antibiotics in chronic inflammatory sinopulmonary diseases

It is well established that macrolide antibiotics are efficacious in treating sinopulmonary infections in humans. However, a growing body of experimental and clinical evidence indicates that they also express distinct salutary effects that promote and sustain the reparative process in the chronically inflamed upper and lower respiratory tract. Unlike the anti-infective properties, these distinct effects are manifested at lower doses, usually after a relatively prolonged period (weeks) of treatment, and in the absence of an identifiable, viable pathogen. Long-term, low-dose administration of macrolide antibiotics has been used most commonly for sinusitis, diffuse panbronchiolitis, asthma, bronchiectasis, and cystic fibrosis. It is associated with down-regulation of nonspecific host inflammatory response to injury and promotion of tissue repair. Although large-scale trials are lacking, the prolonged use of these drugs has not been associated with emergence of clinically significant bacterial resistance or immunosuppression. Long-term, low-dose administration of 14- and 15-membered ring macrolide antibiotics may represent an important adjunct in the treatment of chronic inflammatory sinopulmonary diseases in humans.

Addition of a 2-month low-dose course of levofloxacin to long-term erythromycin therapy in sinobronchial syndrome

BACKGROUND

We previously reported that a 6-month low-dose course of ofloxacin combined with long-term low-dose erythromycin therapy (EM therapy) was superior to EM therapy alone for sinobronchial syndrome (SBS), especially during the initial 2 months of treatment. However, there was no data as to whether discontinuation of low-dose ofloxacin after 2 months results in symptom relapse. This study was designed to clarify this issue.

METHODOLOGY

Twenty-three patients with SBS received a 2-month course of levofloxacin (LVFX) therapy (100 mg once a day) concurrent with a 6-month course of EM therapy (200 mg three times a day) (group A). Eighteen other patients were given the EM therapy alone (group B). Clinical parameters, including quantity of morning sputum, were recorded in a daily symptom diary, and reviewed by each doctor in charge at 2-4 week intervals.

RESULTS

The quantity of morning sputum decreased more rapidly in group A than in group B. No relapse of symptoms was recognized after discontinuation of LVFX in group A.

CONCLUSIONS

A 2-month low-dose course of LVFX in conjunction with long-term EM therapy may be efficacious for the treatment of SBS, as evidenced by rapid improvement of expectoration without any relapse after LVFX discontinuation.

Inhibitory action of a macrolide antibiotic, roxithromycin, on co-stimulatory molecule expressions in vitro and in vivo

OBJECTIVE

The influence of a macrolide antibiotic, roxithromycin (RXM), on co-stimulatory molecule expression was examined in vitro and in vivo.

MATERIALS AND METHODS

Spleen cells obtained from BALB/c mice 10 days after immunization with 8.0 microg of hemocyanin absorbed to 4.0 mg of aluminum hydroxide were cultured in the presence of 100.0 microg/ml of hemocyanin and various concentrations of RXM. We first examined the influence of RXM on cell activation by examining the proliferative response of cells and cytokine production. We also examined the influence of RXM on co-stimulatory molecule (CD40, CD80 and CD86) expressions on cultured splenic B-lymphocytes induced by in vitro antigenic stimulation using flow cytometry. In the second part of experiments, non-immunized and immunized mice were treated orally with 2.5 mg/kg of RXM once a day for 4 or 8 weeks. Splenic B lymphocytes were obtained from these mice 24 h after antigenic challenge, and co-stimulatory molecule expressions were examined by flow cytometer.

RESULTS

Cell activation induced by in vitro antigenic stimulation was suppressed by RXM when cells were cultured in the presence of more than 5.0 microg/ml of the agent. Addition of RXM at a concentration of 5.0 microg/ml into cell cultures also suppressed co-stimulatory molecule (CD40, CD80 and CD86) expressions on splenic B lymphocytes, which was enhanced by antigenic stimulation in vitro. Oral RXM administration for 4 weeks clearly suppressed the enhancement of CD40 and CD86 (but not CD80) expressions on splenic B lymphocytes induced by antigenic stimulation in vivo. This suppressive activity of RXM on co-stimulatory molecule (CD40 and CD86) expressions was further strengthened by the treatment of mice for 8 weeks. Long-term treatment with oral RXM also suppressed CD80 expressions, which was not suppressed by 4-week treatment.

CONCLUSION

The present results suggest that RXM exerts its immunomodulating effects through suppression of both cell activation and co-stimulatory molecule expressions induced by antigenic stimulation. These suppressive activities of RXM might contribute, in part, to the therapeutic mode of action of RXM on inflammatory diseases.

In vitro response of human gingival epithelioid S-G cells to minocycline

Minocycline, a broad-spectrum antibiotic used in the treatment of acne and periodontal disease and to control inflammatory diseases such as rheumatoid arthritis, has recently been shown to induce a spectrum of adverse health effects. In the light of these contradictory data, this research was directed to provide basic information on the toxicology of minocycline, using in vitro cell culture models, and to evaluate its efficacy in periodontal therapies, particularly for wound healing. The human gingival epithelioid S-G cell line was used as the bioindicator. The greater toxicity of minocycline over doxycycline and tetracycline, related antimicrobial agents, probably correlated with its higher lipophilicity. The cytotoxicity of minocycline was unaffected by an S9 hepatic microsomal fraction, indicating that it is a direct-acting, rather than a metabolism-mediated, cytotoxicant. In comparative toxicity studies, much variation in the degree of sensitivity to minocycline was noted for different cell types. No correlation in the extent of sensitivity to minocycline and the physiologic state of the bioindicator cell (normal, transformed or malignant) was noted. The toxicity of minocycline to the S-G cells was dependent on its concentration and length of exposure. For a continuous 3-day exposure of the S-G cells to minocycline, the midpoint cytotoxicity (or, NR(50)) value, as quantified in the neutral red (NR) assay, was 204 microg/ml on day 1, 84 microg/ml on day 2, and 59 microg/ml on day 3. For a 1-h exposure of the S-G cells in phosphate buffered saline (PBS), the NR(50) value was 780 microg/ml minocycline. Although a 1-h exposure in PBS to 200 microg/ml minocycline exerted some toxicity, the S-G cells recovered on exposure to growth medium; irreversible, progressive damage occurred at 400 microg/ml minocycline and greater. Minocycline, at 50 microg/ml, enhanced attachment of the S-G cells to a gelatin-coated surface and cell migration towards an immobilized fibronectin gradient, both biologic parameters important in periodontal wound healing. Minocycline generally had little or no effect on production of the pro-inflammatory cytokines, interleukin-6 (IL-6) and interleukin-8 (IL-8), by non-activated S-G cells, the exception being stimulation of IL-6 at 48 h. IL-1beta, however, greatly stimulated IL-6 and IL-8 production, which was further increased by concurrent exposure to minocycline. This suggested that minocycline may enhance the ability of gingival epithelial cells to participate in the early, inflammatory phase of periodontal wound healing. The limitation of minocycline efficacy to a rather narrow window of concentration, centering about 50 microg/ml, and primarily for short-term exposures may possibly explain, in part, the contradictory clinical data on the health effects of this drug.

Influence of a macrolide antibiotic, roxithromycin, on mast cell growth and activation in vitro

BACKGROUND

Long-term administration of macrolide antibiotics is recognized to be able to favorably modify the clinical condition of inflammatory diseases, such as diffuse panbronchiolitis and cystic fibrosis. However, the precise mechanisms by which macrolide antibiotics could improve clinical conditions of the patients are not well understood.

AIM

The present study was designed to examine the influence of macrolide antibiotics on effector cell functions responsible for inflammation through the choice of roxithromycin (RXM) and mast cell.

METHODS

Mast cells were induced by long-term culture of splenocytes from BALB/c mice. RXM was added to the cultures at seeding and then every 4-5 days, when the culture medium was replaced with a fresh one. The influence of RXM on mast cell growth was evaluated by counting the number of cells grown on the 16th day. We also examined the influence of RXM on mast cell activation by examining histamine release and inflammatory cytokine secretion.

RESULTS AND CONCLUSION

RXM could not inhibit mast cell growth, even when splenocytes were exposed to 100 microg/ml of RXM throughout the entire culture periods. RXM also could not suppress histamine release from cultured mast cells in response to non-immunological and immunological stimulations. However, RXM could suppress inflammatory cytokine, interleukin-1beta, interleukin-6, granulocyte macrophage-colony stimulating factor and tumor necrosis factor-alpha, secretions induced by concanavalin A stimulation at a concentration of as little as 0.5 microg/ml. These results may suggest that RXM modulated the ability of mast cells to secrete inflammatory cytokines and results in improvement of clinical condition of chronic inflammatory diseases.

Anti-inflammatory capabilities of macrolides

Macrolide antibiotics play a significant role in clinical practise due not only to their antibacterial activity, but also to their accompanying anti-inflammatory effect that is independent of their antibiotic action. Several studies reported in literature show that macrolides affect several inflammatory processes, such as migration of neutrophils, the oxidative burst in phagocytes and production of pro-inflammatory cytokines, although the precise mechanisms are not clear. They also inhibit eosinophilic inflammation and may be useful in the treatment of patients with steroid-dependent asthma. Macrolides are also effective in diffuse panbronchiolitis, chronic sinusitis and inflammatory skin diseases.

Modulation of Th2 type cytokine production from human peripheral blood leukocytes by a macrolide antibiotic, roxithromycin, in vitro

The influence of a macrolide antibiotic, roxithromycin (RXM), on Th1 and Th2 cytokine productions from human peripheral blood T cells was examined under stimulation with co-stimulatory molecules. Peripheral blood T cells prepared from both healthy and allergic rhinitis donors were cultured in the presence of RXM on anti-CD3 mAb and anti-CD26 mAb-coated wells, anti-CD3 mAb and anti-CD28 mAb-coated wells, and anti-CD3 and PMA. T-cell proliferation, along with the concentration of interleukin (IL)-2, interferon (IFN)-gamma, IL-4 and IL-5 were measured. RXM did not affect T-cell proliferation induced by several ways of co-stimulatory activation as assessed by 3H-thymidine incorporation into DNA. RXM also had no effect on IL-2 and IFN-gamma secretion by T cells prepared from both healthy and allergic rhinitis donors. On the other hand, RXM markedly inhibited both IL-4 and IL-5 secretions under each of the co-stimulatory conditions in a dose-dependent manner. These results indicate that RXM inhibits specifically Th2 cytokine secretion from T cells induced by co-stimulatory molecule stimulations. This inhibitory action of RXM may be partially responsible for attenuating effect of the agent on the inflammatory diseases.

Effect of palmitic acid on neutrophil functions in vitro

BACKGROUND

It has been shown that in acne comedones the proportion of linoleic acid is markedly decreased, while palmitic acid is significantly increased. We previously reported that the decreased proportion of linoleic acid, which markedly suppresses neutrophil reactive oxygen species (ROS) generation and phagocytosis, contribute to the worsening of acne inflammation. The aim of this study was to examine the effect of palmitic acid on neutrophil functions in vitro.

METHODS

We investigated the effect of palmitic acid on inflammatory parameters such as neutrophil chemotaxis, phagocytosis, and ROS generation. Reactive oxygen species generation in a cell-free, xanthine-xanthine oxidase system was also assessed. The species examined were superoxide radical anion (O2-), hydrogen peroxide (H2O2), and hydroxyl radical (OH.).

RESULTS

Palmitic acid significantly decreased H2O2 generation both by neutrophils and in the xanthine-xanthine oxidase system, while neutrophil chemotaxis and phagocytosis as well as O2- and OH. generation by both systems were not markedly affected in the presence of palmitic acid.

CONCLUSIONS

The present study suggests that palmitic acid may be involved in the pathogenesis of acne inflammation from a standpoint of oxidative tissue injury.

Potential anti-androgenic activity of roxithromycin in skin

Since acne formation is a multistep process accelerated by androgens, we examined whether a new anti-acne antibiotic roxithromycin (RXM) may act as anti-androgen using transient transfection assays in human skin fibroblasts. The result showed no significant effect of 0.5, 1 and 5 microg/ml RXM on 10(-9) M R1881-induced androgen receptor (AR) transcriptional activity. While the cotransfection of exogenous ARA55, a novel AR coactivator, increased AR transactivation up to 2.59-fold, this increase was attenuated by 5 microg/ml RXM to 64.7%. Semiquantitative RT-PCR results showed that 0.1 mM H(2)O(2) treatment increased ARA55 mRNA expression level, indicating that reactive oxygen species increase the expression of ARA55 in skin. These results suggest that RXM may serve as anti-androgen only in the hypersensitive state to androgen, but not in the physiological state, through modulating end-organ hypersensitive condition to androgen possibly involving the pathway from reactive oxygen species to ARA55.

Suppression of co-stimulatory molecule expressions on splenic B lymphocytes by a macrolide antibiotic, roxithromycin in vitro

The influence of a macrolide antibiotic, roxithromycin (RXM), on co-stimulatory molecule expression was examined using in vitro cell culture technique. Spleen cells obtained from BALB/c mice 10 days after immunization with 8.0 micrograms of haemocyanin absorbed to 4.0 mg aluminum hydroxide were cultured in the presence of 100.0 micrograms/ml haemocyanin and various concentrations of RXM for 72 h. Low concentrations (1.0 and 2.5 micrograms/ml) of RXM did not influence cell activation induced by antigenic stimulation, whereas RXM showed a suppressive effect on blastic activity of the cells when the agent was added to the cultures at more than 5.0 micrograms/ml. RXM did not affect blastic activity of splenic T cells by anti-CD3 monoclonal antibody stimulation even when the cells were cultured in the presence of 10.0 micrograms/ml RXM. Addition of anti-CD80 and anti-CD86 monoclonal antibody to cell cultures caused significant suppression of cell activation by antigenic stimulation. We next examined the influence of RXM on co-stimulatory molecule expressions on splenic B cells in response to antigenic stimulation. Addition of RXM at a concentration of 5.0 micrograms/ml into cell cultures remarkably suppressed co-stimulatory molecule, CD40, CD80 and CD86, expressions, which enhanced by antigenic stimulation in vitro.

Is acne an infection of blocked pilosebaceous follicles? Implications for antimicrobial treatment

A model is proposed which is based on the assumption that acne is due to infection of functionally blocked pilosebaceous follicles by propionibacteria. Noninflamed lesions, which are first visible during the adrenarche in acne-prone individuals, do not contain propionibacteria. Comedogenesis appears to be independent of bacterial infection and may be driven by high levels of bioactive interleukin-1 alpha derived from ductal hyperkeratinocytes. The stimulus which triggers interleukin-1 alpha production is unknown. Formalin killed Propionibacterium acnes failed to stimulate production of the cytokine by cultured human keratinocytes in vitro. Inflamed lesions are thought to arise from microcomedones, but the initiating events are unknown. Evidence that propionibacteria are involved in the generation of inflammatory lesions is inconclusive. The cellular infiltrate is consistent with a type IV hypersensitivity response to one or more persistent lesional antigens, not necessarily bacterial. The potent adjuvant activity of P. acnes would up-regulate the immune response to any antigen which came into contact with the mononuclear cell infiltrate. Antibiotics are widely used in the treatment of acne, and their effects in selecting a predominantly resistant commensal population are well recognized. Although they reduce numbers of propionibacteria on the skin, other modes of action may contribute to or explain their therapeutic efficacy. At a time when there is global concern that antibiotic resistance rates in common bacterial pathogens may threaten our future ability to control bacterial infections, practices which promote the spread of antibiotic-resistant bacteria must be fully justified. A thorough reappraisal of the role of propionibacteria in acne is overdue. It is likely that further experimental work is needed to confirm or refute that P. acnes is aptly named.

Suppressive activity of a macrolide antibiotic, roxithromycin on co-stimulatory molecule expression on mouse splenocytes in vivo

The influence of roxithromycin (RXM) on the expression of co-stimulatory molecules, CD40, CD80 and CD86, was examined in vivo. When BALB/c mice were immunized intraperitoneally with two doses of dinitrophenylated ovalbumin (DNP-OVA) at 1 week intervals, intraperitoneal administration of RXM at 250 microg/kg once a day for 14 days strongly suppressed IgE contents in sera obtained from mice 22 days after the first immunization. In addition, RXM treatment of mice suppressed endogenous IL-4 contents in aqueous spleen extracts, which were enhanced by DNP-OVA immunization. We next examined the influence of RXM on co-stimulatory molecule expression on splenic lymphocytes. RXM treatment of the immunized mice caused suppression of CD40 expression, but this treatment did not affect CD80 and CD86 expression.

Roxithromycin down-modulates antigen-presenting and interleukin-1 beta-producing abilities of murine Langerhans cells

The immunomodulatory effect of the macrolide antibiotic, roxithromycin (RXM) on Langerhans cells (LC) was studied in mice. RXM inhibited the ability of LC to present superantigen and hapten to T cells at 100 microM. The superantigen-presenting activity of LC was more profoundly abrogated by RXM than the hapten-presenting activity. This functional reduction was partly attributed to an RXM-induced decrease in promotion of the expression of major histocompatibility complex class II molecules on LC. On the other hand, RXM down-modulated the production of interleukin-1 beta by LC at a lower concentration of 10 microM than concentrations that inhibited antigen presentation. These results imply that RXM exerts therapeutic effectiveness via not only bacteriocidal action but also inhibitory effect on the LC ability in T-cell-mediated cutaneous diseases that can be exacerbated by skin-colonized Staphylococcus aureus.

Roxithromycin, clarithromycin, and azithromycin attenuate the injurious effects of bioactive phospholipids on human respiratory epithelium in vitro

The effects of the bioactive phospholipids (PL), platelet-activating factor (PAF), lyso-PAF, and lysophosphatidylcholine (LPC) on the beat frequency and structural integrity of human ciliated respiratory epithelium were studied in vitro, in the presence or absence of polymorphonuclear leukocytes (PMNL), the antimicrobial agents, roxithromycin, clarithromycin, and azithromycin and the antioxidative enzymes catalase and superoxide dismutase (SOD). All three PL caused dose-dependent slowing of ciliary beat frequency (CBF) and epithelial damage (ED) at concentrations > or = 1 microgram/ml, which were unaffected by inclusion of the antimicrobial agents and antioxidative enzymes. When epithelial strips were exposed to the combination of PMNL and PL, there was significant potentiation of ciliary dysfunction and ED, which was ameliorated by pretreatment of the PMNL with the antimicrobial agents or by inclusion of catalase, but not SOD. These results demonstrate that LPC, PAF, and lyso-PAF cause epithelial damage by direct mechanisms which are oxidant-independent, as well as by indirect mechanisms involving phagocyte-derived reactive oxidants. Macrolides and azalide antimicrobial agents may have beneficial effects on airway inflammation in asthma and microbial infections by protecting ciliated epithelium against oxidative damage inflicted by PL-sensitized phagocytes.

Effect of keigai-rengyo-to, a Japanese kampo medicine, on neutrophil functions: a possible mechanism of action of keigai-rengyo-to in acne

On the basis of recent reports that keigai-rengyo-to (TJ-50), an oral Japanese Kampo (herb) medicine, is clinically effective in treating acne, and that tetracyclines are effective against acne by acting directly as an antioxidant on infiltrated neutrophils, we investigated the effect of TJ-50 on the generation of reactive oxygen species (ROS), using human neutrophils and a cell-free, xanthine-xanthine oxidase system. The species investigated were superoxide radical anion (O2-), hydrogen peroxide (H2O2), and hydroxyl radical (OH.). In addition, neutrophil chemotaxis, phagocytosis and calcium concentration, [Ca2+]i in neutrophils were also assessed. TJ-50 significantly decreased neutrophil-generated O2-, H2O2 and OH. in a dose-dependent manner. Three kinds of ROS generated in the cell-free system were also reduced in the presence of TJ-50. On the other hand, the medicine did not markedly affect neutrophil chemotaxis, phagocytosis or [Ca2+]i in neutrophils. Our results indicate that the clinical effectiveness of TJ-50 in the treatment of acne may be due partly to its antioxidant action on infiltrated neutrophils.

Are the reactive oxygen-derived species (ROS) interactive properties of the many therapeutic drugs from various categories pertinent to their beneficial effects?

Many pathologic states are known to involve the generation of reactive oxygen species, (ROS). It is not known at present to what extent these phenomena are due to ROS formation, or if their formation is a result of the disease. Many therapeutic drugs either scavenge ROS or inhibit their formation. The purpose of this review is to match the drugs used for certain diseases with their anti-ROS actions. This attempted correlation is made to try to give an answer to the title question.

Membrane-stabilizing, anti-inflammatory interactions of macrolides with human neutrophils

The effects of the macrolide antimicrobial agents azithromycin, clarithromycin, erythromycin and roxithromycin on the prooxidative activity of stimulated human neutrophils have been investigated in vitro. Superoxide generation by activated neutrophils was measured by lucigenin-enhanced chemiluminescence. At the concentrations used (2.5-80 micrograms/ml) none of the test agents was cytotoxic, nor did they possess superoxide-scavenging properties. Treatment of neutrophils with all 4 macrolides was accompanied by dose-related inhibition of superoxide production by cells activated with FMLP or the calcium ionophore (A23187), while the responses activated by phorbol myristate acetate (PMA) or opsonized zymosan were minimally affected. The anti-oxidative interactions of roxithromycin with FMLP-activated neutrophils were neutralized by pretreatment of the cells with low, non-cytotoxic concentrations (0.5 microgram/ml) of the prooxidative, proinflammatory bioactive phospholipids, lysophosphatidylcholine (LPC), platelet-activating factor (PAF) and lyso-PAF (LPAF). Using an assay of membrane-stabilizing activity, the macrolides antagonized the membrane-disruptive effects of LPC, PAF and LPAF, without affecting enzymes involved in their synthesis. These membrane-stabilizing interactions of macrolides with neutrophils may counteract the proinflammatory, prooxidative activity of several bioactive lipids which have been implicated in the pathogenesis of bronchial asthma.

Effect of pyridone carboxylic acid anti-microbials on the generation of reactive oxygen species in vitro

The effects of ofloxacin, ciprofloxacin and balofloxacin on the reactive oxygen species (ROS) levels generated by human neutrophils was examined in vitro; ROS generated in a cell-free, xanthine-xanthine oxidase system was also assessed. The species investigated were superoxide radical anion (O2-), hydrogen peroxide (H2O2) and hydroxyl radical (OH*). Both ofloxacin and ciprofloxacin markedly decreased the levels of O2-, H2O2 and OH* generated by human neutrophils. On the other hand, these drugs did not affect any of the ROS examined in the xanthine-xanthine oxidase system. Balofloxacin showed no significant effect on ROS generated by either system. The present study indicates that ofloxacin and ciprofloxacin may exert an anti-inflammatory action by reducing the potent ROS species excessively generated by neutrophils at the sites of inflammation.

Effect of macrolide antibiotics on macrophage functions

Macrolide antibiotics have a variety of actions other than antimicrobial activities. Recently, it has been suggested that macrolide antibiotics act as immunomodulators. In this study, we evaluated the effects of macrolide antibiotics on macrophage functions. For the macrophage, we used the mouse macrophage cell line J774.1. The following effects of macrolide antibiotics on macrophage functions were evaluated: the effect of macrolide antibiotics on macrophage growth; the phagocytosis of beads; cytocidal activity against Candida albicans; and chemotaxis to lipopolysaccharide (LPS). Macrolide antibiotics except for azithromycin significantly stimulated the growth of the macrophage. In addition, pretreatment with macrolide antibiotics except for roxithromycin significantly stimulated the macrophage phagocytosis of beads, macrophage chemotaxis to LPS, and macrophage cytocidal activity against Candida albicans. These results suggest that macrolide antibiotics stimulate macrophage functions.

Treatment of actinic prurigo in Chimila Indians

BACKGROUND

Actinic prurigo has a high prevalence in women of child-bearing age. Its treatment has been, among others, with thalidomide. To avoid the deleterious effects of this drug on the embryo, therapeutic alternatives have been sought. Among these, tetracycline and vitamin E have been investigated as to their influence on the symptoms of actinic prurigo. Both these drugs affect superoxide radicals that are thought to be involved in the pathogenesis of actinic prurigo.

MATERIALS AND METHODS

Patients (Chimila Indians with a high prevalence of actinic prurigo) received either (a) tetracycline, 500 mg three times daily, for 6 months, or (b) vitamin E, 100 IU daily, for 6 months. The patients were seen once monthly. There were eight patients in each group.

RESULTS

Both drugs used were effective. Pruritus was remarkably improved by either treatment. None of the side effects were severe enough to lead to interruption of treatment, but the observation period posttreatment was relatively short, 4 months for tetracycline and 2 months for vitamin E. The improvement occurred in spite of the continuation of extensive exposure to the sun.

CONCLUSIONS

Tetracycline and vitamin E are efficacious in relieving the pruritus of actinic prurigo. Preliminary trials of a combination treatment with these two drugs is a new avenue which has shown in preliminary trials to yield synergistic effects which might allow the dosage of tetracycline to be reduced.

Clinical evaluation of roxithromycin in patients with acne

On the basis of reports that erythromycin is effective in the treatment of acne, we investigated whether roxithromycin (ROM), a new derivative of erythromycin, might also be effective in treating acne. Roxithromycin was administered to 30 patients with acne for 8 weeks. General improvement was assessed 8 weeks after the initiation of the therapy with a six-graded scale as follows; 1: good improvement, 2: moderate improvement, 3: slight improvement, 4: no change, 5: worsening, and 6: no assessment. The percentage of good or moderate improvement was 73.3%, and that of good improvement alone was 20.0%. Our results suggest that ROM is effective in the treatment of acne.