Connectivity of the intracytoplasmic membrane of Rhodobacter sphaeroides: a functional approach.

The photosynthetic apparatus in the bacterium Rhodobacter sphaeroides is mostly present in intracytoplasmic membrane invaginations. It has long been debated whether these invaginations remain in topological continuity with the cytoplasmic membrane, or form isolated chromatophore vesicles. This issue is revisited here by functional approaches. The ionophore gramicidin was used as a probe of the relative size of the electro-osmotic units in isolated chromatophores, spheroplasts, or intact cells. The decay of the membrane potential was monitored from the electrochromic shift of carotenoids. The half-time of the decay induced by a single channel in intact cells was about 6 ms, thus three orders of magnitude slower than in isolated chromatophores. In spheroplasts obtained by lysis of the cell wall, the single channel decay was still slower (~23 ms) and the sensitivity toward the gramicidin concentration was enhanced 1,000-fold with respect to isolated chromatophores. These results indicate that the area of the functional membrane in cells or spheroplasts is about three orders of magnitude larger than that of isolated chromatophores. Intracytoplasmic vesicles, if present, could contribute to at most 10% of the photosynthetic apparatus in intact cells of Rba. sphaeroides. Similar conclusions were obtained from the effect of a ∆pH-induced diffusion potential in intact cells. This caused a large electrochromic response of carotenoids, of similar amplitude as the light-induced change, indicating that most of the system is sensitive to a pH change of the external medium. A single internal membrane and periplasmic space may offer significant advantages concerning renewal of the photosynthetic apparatus and reallocation of the components shared with other bioenergetic pathways.

AntihypoxamiR functionalized gramicidin lipid nanoparticles rescue against ischemic memory improving cutaneous wound healing.

Peripheral vasculopathies cause severe wound hypoxia inducing the hypoxamiR miR-210. High level of miR-210, persisting in wound-edge tissue as ischemic memory, suppresses oxidative metabolism and inhibits cell proliferation necessary for healing. In wound-edge tissue of chronic wound patients, elevated miR-210 was tightly associated with inhibition of epidermal cell proliferation as evident by lowered Ki67 immunoreactivity. To inhibit miR-210 in murine ischemic wound-edge tissue, we report the formulation of antihypoxamiR functionalized gramicidin lipid nanoparticles (AFGLN). A single intradermal delivery of AFGLN encapsulating LNA-conjugated anti-hypoximiR-210 (AFGLNmiR-210) lowered miR-210 level in the ischemic wound-edge tissue. In repTOP™mitoIRE mice, AFGLNmiR-210 rescued keratinocyte proliferation as visualized by in vivo imaging system (IVIS). 31P NMR studies showed elevated ATP content at the ischemic wound-edge tissue following AFGLNmiR-210 treatment indicating recovering bioenergetics necessary for healing. Consistently, AFGLNmiR-210 improved ischemic wound closure. The nanoparticle based approach reported herein is effective for miR-directed wound therapeutics warranting further translational development.

Effect of sofosbuvir and daclatasvir on lipid profile, glycemic control and quality of life index in chronic hepatitis C, genotype 3 patients.

OBJECTIVES: The management of hepatitis C has progressed from interferon-based therapy to oral direct acting antiviral therapy. Deranged lipid levels (total cholesterol, triglyceride) after treatment with interferon-based therapy are well known. There is a paucity of data on changes in lipid profile, glycemic parameters and alteration in quality of life with the newer regimen. This study was designed to assess the changes in lipid profile, glycemic parameters, quality of life in chronic hepatitis C patients with genotype 3 after treatment with sofosbuvir and daclatasvir. METHODS: The study was a single-centre, prospective study, conducted at tertiary care hospital from January 2017 to December 2017. Fifty patients, who received sofosbuvir (400 mg) and daclatasvir (60 mg) orally once daily for a period of 12 weeks for chronic hepatitis C and genotype 3, were recruited. RESULTS: Total cholesterol levels (166.9 ± 23.8 to 192.4 ± 34.5 mg/dL, p-value < 0.0001) and low-density cholesterol (LDL) levels (100.9 ± 22.8 to 121.6 ± 37.2, p-value < 0.0001) were elevated after the treatment. A significant decrease in median levels of glycated hemoglobin (HbA1c) was observed (5.57% to 5.41%, p-value < 0.002). Quality of life markedly improved in all domains, i.e. physical, physiological, environmental, and social relationships according to an abbreviated form of World Health Organization quality of life assessment named WHOQOL-BREF questionnaire. Treatment was found to be effective with sustained virological response (SVR) achieved in 94% patients. CONCLUSIONS: Our study reports a substantial increment in total cholesterol, and low-density lipoprotein with sofosbuvir and daclatasvir treatment though it achieved SVR in 94% of patients and improved their quality of life.

Topical ciprofloxin versus topical framycetin-gramicidin-dexamethasone in Australian aboriginal children with recently treated chronic suppurative otitis media: a randomized controlled trial.

BACKGROUND: Chronic suppurative otitis media (CSOM) affects many children in disadvantaged populations. The most appropriate topical antibiotic treatment in children with persistent disease is unclear. METHODS: Children with CSOM despite standard topical treatment were randomized to 6-8 weeks of topical ciprofloxacin (CIP) versus topical framycetin-gramicidin-dexamethasone (FGD). Otoscopic, audiologic, and microbiologic outcomes were measured using standardized assessments and blinding. RESULTS: Ninety-seven children were randomized. Ear discharge failed to resolve at the end of therapy in 70% children regardless of allocation [risk difference = -2%; (95% CI: -20 to 16)]. Healing of the tympanic membrane occurred in one of 50 children in the CIP group and none of 47 children in the FGD group. Severity of discharge failed to improve in more than 50% children in each group, and mean hearing threshold (38 dB and 35 dB) and proportion of children with greater than 25 dB hearing loss (98% and 88%) were not significantly different between the CIP and FGD groups. Side effects were rare. CONCLUSIONS: This study showed a similarly low rate of improvement or cure in children with persistent CSOM for both CIP and FGD topical therapies. Complications and side effects were insufficient to cease therapy or inform prescribing of either therapy.

Growth inhibition of Plasmodium falciparum in in vitro cultures by selective action of tryptophan-N-formylated gramicidin incorporated in lipid vesicles.

We studied the differential effect of tryptophan-N-formylated gramicidin on uninfected and Plasmodium falciparum-infected erythrocytes. Trp-N-formylated gramicidin induces a much faster leakage of K+ from infected cells than from uninfected cell whereas, and at an even lower concentration, gramicidin A' causes a rapid K+ leakage from both uninfected and infected cells. We also studied the effect of Trp-N-formylated gramicidin and gramicidin A' incorporated in liposomes on the growth of Plasmodium falciparum in an in vitro culture. Incorporation of Trp-N-formylated gramicidin in the membranes of so-called 'stealth' vesicles strongly decreases the concentration needed to induce 50% inhibition of parasite growth. Moreover, no decrease in the K+ content of uninfected cells was observed when cells were exposed to liposome-incorporated Trp-N-formylated gramicidin at a concentration which causes full inhibition of parasite growth. These observations strongly suggest that Trp-N-formylated gramicidin incorporated in 'stealth' vesicles ends up specifically in the infected cell, thereby inhibiting the growth of the growth of the malaria parasite.

Effectiveness of combined antibiotic ophthalmic solution in the treatment of hordeolum after incision and curettage: a randomized, placebo-controlled trial: a pilot study.

The presented pilot study compared the effectiveness of combined antibiotic ophthalmic solution (neomycin sulfate, polymyxin B sulfate and gramicidin) with a placebo (artificial tear) in the treatment of hordeolum after incision and curettage (I&C). A randomized, placebo-controlled trial with patients and investigators blinded from the start started from June 2002 to May 2003. Subjects were patients with untreated hordeolum who subsequently underwent I&C at the Ophthalmology Department. The patients were randomized into 2 groups: group A for combined antibiotic ophthalmic solution, and group B for artificial tear containing the antibiotic solution base. Pain score, mass size and duration of cure were recorded before and on the 3rd and 7th day after treatment. The study included 14 patients in each group. Two subjects in group A and three subjects in group B dropped out. There were no statistically significant differences of all outcomes in both groups, even with the intention-to-treat analysis. The conclusion is combined antibiotic ophthalmic solution is not more effective than placebo in the treatment of hordeolum after I&C.

Polymersomes with engineered ion selective permeability as stimuli-responsive nanocompartments with preserved architecture.

Following a biomimetic approach, we present here polymer vesicles (polymersomes) with ion selective permeability, achieved by inserting gramicidin (gA) biopores in their membrane. Encapsulation of pH-, Na(+)- and K(+)- sensitive dyes inside the polymersome cavity was used to assess the proper insertion and functionality of gA inside the synthetic membrane. A combination of light scattering, transmission electron microscopy, and fluorescence correlation spectroscopy was used to show that neither the size, nor the morphology of the polymersomes was affected by successful insertion of gA in the polymer membrane. Interestingly, proper insertion and functionality of gA were demonstrated for membranes with thicknesses in the range 9.2-12.1 nm, which are significantly greater than membrane lipid counterparts. Both polymersomes with sizes around 100 nm and giant unilamellar vesicles (GUVs) with inserted gA exhibited efficient time response to pH- and ions and therefore are ideal candidates for designing nanoreactors or biosensors for a variety of applications in which changes in the environment, such as variations of ionic concentration or pH, are required.

'Chemical condoms' for the prevention of HIV infection: evaluation of novel agents against SHIV(89.6PD) in vitro and in vivo.

BACKGROUND: Vaginal agents which are antiviral and/or inhibit the entry of HIV into the cell could prevent heterosexual transmission of HIV, and protect women who cannot negotiate condom use. METHODS: Four agents have been investigated for activity in vitro and in vivo against SHIV(89.6PD): two anionic polymers, dextrin-2-sulphate (D2S) and PRO 2000 (P2K), and two virucidal agents; a non-ionic detergent, nonoxynol-9 (N9) and a cyclic peptide ionophore, gramicidin-D (GD). All four agents were investigated in rhesus macaques, using an intra-vaginal challenge of two inoculations of 1 x 104 50% tissue culture infectious doses (TCID)50 of SHIV(89.6PD). RESULTS: D2S, P2K, GD and N9 all inhibited SHIV(89.6PD) in vitro. In vivo, three out of four control macaques were infected as judged by viral culture, seroconversion, DNA and RNA PCR; infection was confirmed in four out of eight macaques pre-treated with P2K, two out of four pre-treated with D2S, one out of four pre-treated with N9, two out of four pre-treated with GD and four out of four pre-treated with D2S + GD, a combination additive in vitro. INTERPRETATION: D2S and PRO-2000, novel inhibitors of HIV entry, showed evidence of protection in vivo, comparable to that seen with the virucide, N9. These data, together with the results of phase I and phase II studies in healthy women which have shown minimal toxicity, support plans for a phase III efficacy trial of chemically simple inhibitors of HIV entry with low toxicity, for the prevention of HIV infection in women.

Comparison of topical tobramycin-dexamethasone with dexamethasone-neomycin-polymyxin and neomycin-polymyxin-gramicidin for control of inflammation after cataract surgery: results of a multicenter, prospective, three-arm, randomized, double-masked, controlled, parallel-group study.

BACKGROUND: Intraocular inflammation is typically treated with a combination of anti-inflammatory and anti-infective drugs. Tobramycin-dexamethasone (TD) has not been associated with any serious adverse events, indicating good tolerability. OBJECTIVE: The aims of this study were the following: (1) to demonstrate noninferiority of TD compared with dexamethasone-neomycin-polymyxin (DNP) in terms of anti-inflammatory efficacy, (2) to compare the anti-inflammatory efficacy of TD and DNP with that of a "placebo" control (antibiotic without anti-inflammatory agent), and (3) to provide additional safety data on TD. METHODS: This prospective, double-masked, parallel-group study was conducted at 22 ophthalmology clinics across Europe and Brazil. Patients aged > 18 years undergoing cataract surgery were randomly assigned, in a 2:2:1 ratio, to receive tobramycin 3 mg/mL plus dexamethasone 1 mg/mL, dexamethasone 1 mg/mL plus neomycin sulfate 3500 IU/mL plus polymyxin B sulfate 6000 IU/mL, or neomycin sulfate 3500 IU/mL plus polymyxin B sulfate 7500 IU/mL plus gramicidin 20 microg/mL. All treatments were given as 1 drop instilled in the operated eye q.i.d. for 21 days. The primary efficacy end point, intraocular inflammation (determined using the sum of scores on anterior chamber cells and aqueous flare), was assessed at days 3, 8, 14, and 21 after surgery. RESULTS: A total of 271 patients were enrolled (158 women, 113 men; age range 42-90 years) (TD, 104 patients; DNP, 110 patients; and neomycin-polymyxin-gramicidin [NPG], 57 patients). Intraocular inflammation was similar in the TD and DNP groups at all time points. At days 8, 14, and 21, inflammation scores were significantly lower with TD than with NPG (all, P < 0.05). At day 8, the inflammation score was significantly lower with DNP than with NPG (P < 0.05). A greater number of patients receiving NPG experienced treatment-related ocular allergic reactions compared with patients receiving TD (P < 0.05). One patient receiving TD (1.0%) and 5 given NPG (9.0%) were withdrawn due to ocular allergic reactions. None of the patients experienced an increase in intraocular pressure > or =10 mm Hg from baseline. CONCLUSIONS: In this study of patients undergoing cataract surgery combination therapy with TD was noninferior to DNP and was well tolerated.

Primary meningococcal conjunctivitis.

Neisseria meningitidis is an uncommon cause of acute bacterial conjunctivitis. One case of primary meningococcal conjunctivitis in a healthy 6-year-old boy is reported. The patient was initially treated with a topical instillation of polymyxin B, neomycin and gramicidin in ophthalmic solution, and this was followed by systemic rifampin once the diagnosis had been established. No ocular or systemic complications developed.

Polymer water-soluble derivatives of polypeptide antibiotic, gramicidin-S based on reactive copolymers of N-(2-hydroxypropyl) methacrylamide.

Copolymers of N-(2-hydroxypropyl)methacrylamide with p-nitrophenyl esters of unsaturated phenoxyacetic acids and N-methacryloylglycylleucine and with acrylic acid were synthesized as polymer carriers for obtaining water-soluble polymer forms of an antibiotic gramicidin-S. The kinetics of the aminolysis of copolymers of N-(2-hydroxypropyl) methacrylamide (HPMA) which contain reactive p-nitrophenoxycarbonyl groups by gramicidin-S were investigated. It was established that aminolysis rate depends on the structure of the bridge group which binds p-nitrophenoxycarbonyl group to the main chain of the copolymer. On the basis of these copolymers of HPMA polymer amide and salt derivatives of gramicidin-S were obtained and their composition was determined. It was shown, that the antibacterial activity of these polymer derivatives of gramicidin-S depends on the bond type of the antibiotic with the polymer and attains a relatively high level for polymer salts of gramicidin-S.

Clinical evaluation of trimethoprim-containing ophthalmic solutions in humans.

We studied trimethoprim in combination with sulfacetamide and polymyxin B and also in combination with polymyxin B alone (without the sulfacetamide) to determine the efficacy and safety of these new antibiotic combinations in the eyes of patients with bacterial conjunctivitis or blepharitis. Patients were selected for the study if they showed at least three of the following criteria: (1) symptoms of a surface ocular infection; (2) a purulent discharge; (3) a polymorphonuclear neutrophilic response on Giemsa stain; (4) a history of recent exposure to an infected individual; (5) a history of an inadequately treated surface bacterial infection. Trimethoprim-sulfacetamide-polymyxin B and polymyxin B-neomycin-gramicidin (Neosporin, the control) eliminated bacteria from the eyes of patients with conjunctivitis or blepharitis with equal effectiveness. There was no loss of effectiveness when trimethoprim-polymyxin B was compared with trimethoprim-sulfacetamide-polymyxin B, suggesting that the sulfacetamide was not a necessary component. The combination antibiotic containing trimethoprim and polymyxin B appears to be an effective topical antibiotic solution for the treatment of ocular surface infections.

The effect of povidone-iodine solution applied at the conclusion of ophthalmic surgery.

PURPOSE: Povidone-iodine 5% solution decreases the incidence of postoperative endophthalmitis when used on the eye for preoperative preparation. We sought to determine whether it also minimized conjunctival bacterial flora immediately after surgery by preventing bacteria present on the surface of the eye from entering surgical wounds. METHODS: In 42 eyes of 40 patients, at the conclusion of surgery, on an alternating basis, each patient received either a drop of a broad-spectrum antibiotic solution (polymyxin B sulfate-neomycin sulfate-gramicidin) or a 5% povidone-iodine solution in the operated-on eye. Bacterial cultures were taken before and after surgery and 24 hours later. The 38 unoperated-on eyes in the unilateral cases served as control eyes. RESULTS: Relative to the control group, povidone-iodine was effective in preventing an increase in the number of colony-forming units (P = .035), while the antibiotic was not. At 24 hours after surgery, the species count was lower in the eyes receiving povidone-iodine than in the antibiotic-treated eyes (P = .034) and was increased in the antibiotic group since the completion of surgery (P = .013), but was lower in the povidone-iodine and antibiotic groups than in the control eyes for both groups (P < .01). CONCLUSIONS: Povidone-iodine 5% solution applied to the eye at the conclusion of surgery was more effective at minimizing the number of colony-forming units and species for the first postoperative day than was a broad-spectrum antibiotic. While not true for the antibiotic, the antimicrobial effect of povidone-iodine lasted for at least 24 hours after the completion of surgery.

A general practice study to compare the efficacy and tolerability of a spray ('Otomize') versus a standard drop formulation ('Sofradex') in the treatment of patients with otitis externa.

In an open, multi-centre study in general practice, a comparison was made of the efficacy, tolerability and acceptability of a neomycin/dexamethasone preparation administered by metered-dose spray ('Otomize') and a framycetin/gramicidin/dexamethasone preparation ('Sofradex') administered as drops in 60 patients with otitis externa. Patients were allocated at random to receive one or other preparations 3-times daily for 10 days and were followed-up again 14 days after cessation of therapy. Clinical assessments were carried out under observer blind conditions on entry (Day 0) and on Days 10 and 24 of the severity of erythema, swelling and debris in the affected ear(s). A global assessment of clinical outcome was made by the doctor on Day 10. There were no significant differences in the two groups at the start of treatment. Significant improvement occurred in both groups from Day 0 to Day 10 and from Day 10 to Day 24 in all symptoms, with the proportion symptom-free in the 'Otomize' group significantly greater than in the 'Sofradex' group at 24 days, and approaching significance at 10 days. Significantly more patients in the 'Otomize' group were rated as having a good clinical outcome by the physician, and fewer patients experienced discomfort on application. Few side-effects were reported by either treatment group, none necessitating discontinuation of therapy.

Diffuse lamellar keratitis induced by trauma 6 months after laser in situ keratomileusis.

This case report illustrates an unusual presentation of diffuse lamellar keratitis triggered by a foreign body striking the eye 6 months after laser in situ keratomileusis (LASIK). The etiology of diffuse lamellar keratitis is unclear. The infiltrate within the plane of the flap after removal of the foreign body supports the theory that diffuse lamellar keratitis is an inflammatory reaction.

Comparative in vitro study of contraceptive agents with anti-HIV activity: gramicidin, nonoxynol-9, and gossypol.

Gramicidin, a polypeptide antibiotic derived from Bacillus brevis, was compared in vitro with the established contraceptive virucidal agents nonoxynol-9 and gossypol for activity against human immunodeficiency virus (HIV) infection. The effective antiviral 10 ng/ml concentration of gramicidin required for complete HIV inactivation was a thousand-fold lower than the dose observed for nonoxynol-9 or gossypol. Gramicidin, routinely used as a contraceptive agent in the former Soviet Union, should be considered for in vivo trials as a spermicide with potent antiviral activity.

PIP: At the New York University Medical Center, researchers used an antiviral assay, p24 ELISA, and cytoxicity assays to compare the antiviral activity of the newly-discovered anti-HIV compound gramicidin with established spermicides that have demonstrated antiviral activity. A 10 ng/ml of gramicidin completely inhibited productive HIV infection in MT-4 lymphocytes, while a 1000-fold higher dose of nonoxynol-9 and gossypol (10 mcg/ml) was needed to achieve the same effect. A possible mechanism is impaired permeability for cations, resulting in inhibition of virus-induced fusion. The study did not try to determine the biochemical mode of gramicidin action, however. Gramicidin is used in the former USSR as an active component of spermicidal gels and foams and as a topical, non-irritating antibiotic often used to treat ocular infections. The results of this in vitro study call for more in vitro studies to determine the biochemical mechanism of gramicidin action and its clinical potential as a vaginal spermicide with antiviral activity.

Dose-response effects of gramicidin-D, EDTA, and nonoxynol-9 on sperm motion parameters and acrosome status.

Previous reports showed that gramicidin-D (G-D), a polypeptide with antiviral and antimicrobial properties, nonoxynol-9 (N9), a common spermicidal detergent, and EDTA, a Ca-Mg chelating agent, inhibited sperm motility and cervical mucus penetration. The purpose of this study was to determine the dose-response effects of G-D, N9, EDTA and G-D + EDTA on sperm motion parameters and acrosome status. Semen specimens from known fertile donors were subjected to computer-assisted semen analysis of motility, path velocity, progressive velocity, and hyperactivation prior to and after incubation with varying concentrations of gramicidin-D, EDTA and nonoxynol-9. Each specimen was also prepared for acrosome status using rhodamine isothiocyanate conjugated pisum sativum agglutinin (RITC-PSA). There was a significant decrease in motility by G-D, EDTA, G-D + EDTA, and N9 at all doses as compared to the fresh specimen. N9 completely immobilized all sperm at each dose. Progressive velocity and path velocity also decreased in a dose-response manner. Sperm hyperactive motility also significantly decreased in all groups. The majority of sperm remained acrosome intact following exposure to all doses tested, whereas N9 resulted in complete breakdown/release of the acrosomal contents. This study confirms previous reports that G-D, EDTA, and N9 significantly impair sperm motility and motion parameters. The effective 100% inhibitory concentration was seen only with N9, whereas G-D, EDTA, and G-D + EDTA resulted in incomplete impairment of sperm motion parameters. At the concentrations used, N9 demonstrated potent spermostatic activity. Gramicidin-D and EDTA should be further studied for their potential contraceptive spermostatic activity.

PIP: Gramicidin-D (G-D), a polypeptide with antiviral and antimicrobial properties, the spermicidal detergent nonoxynol-9 (N-9), and the Ca-Mg chelating agent EDTA have been shown in previous studies to inhibit sperm motility and cervical mucus penetration. This study utilized computer-assisted methods to investigate the dose-response effects of incubation with G-D, N-9, EDTA, and G-D plus EDTA on sperm motion parameters and acrosome status. Semen specimens were acquired within 30 minutes of ejaculation from six fertile US sperm donors. Compared to the fresh (untreated) specimen, there was a significant decrease in sperm motility produced by G-D, EDTA, G-D plus EDTA, and N-9 at all doses. Progressive and path velocity and sperm hyperactive motility also decreased in a dose-response manner in all groups. However, sperm immobilization was complete at the concentrations used only with N-9. The majority of sperm remained acrosome-intact after exposure to all tested doses of G-D and EDTA, but N-9 resulted in complete breakdown and release of the acrosomal contents. A combination of N-9 and G-D or N-9 and EDTA at lower doses might produce the desired inhibition of sperm motility without toxicity and this possibility should be investigated. At the present time, however, G-D or EDTA, alone or in combination, cannot be considered effective contraceptive agents.

Synergistic effect of gramicidin and EDTA in inhibiting sperm motility and cervical mucus penetration in vitro.

Gramicidin, a linear polypeptide with antiviral and antimicrobial properties, was compared in vitro with a commonly used spermicidal detergent-nonoxynol-9 (N9). The inhibition of sperm functions was evaluated by computer-assisted semen analysis (CASA) for sperm motility, in cervical mucus penetration assay, and by colorimetric tetrazolium salt and lactate dehydrogenase release assays routinely employed for testing the toxicity of drugs. The effective 100% inhibitory concentration (IC100) of gramicidin in a 2-min sperm immobilization assay by CASA was equal to 4 micrograms/ml, whereas IC100 of N9 was equal to 200 micrograms/ml. The presence of 0.1% of chelating agent, EDTA, reduced IC100 of gramicidin to 10 ng/ml, while less than a twofold enhancement in N9 activity was observed upon combination with EDTA. Likewise, the gramicidin/EDTA combination was 100,000 times more potent than N9/EDTA in the sperm penetration assay. Quantitative toxicity tests confirmed that gramicidin is a potent spermostatic rather than spermicidal agent. Further development of a gramicidin/EDTA formulation is warranted as a nontoxic topical contraceptive with activity against viral and microbial sexually transmitted diseases (STDs).

PIP: The possibility of enhancing the anti-fertility potential of gramicidin with low doses of ethylenediaminetetraacetic acid (EDTA) was investigated in an in vitro study. The inhibition of sperm functions was evaluated by computer-assisted semen analysis for sperm motility, cervical mucus penetration assay, and colorimetric tetrazolium salt and lactate dehydrogenase release assays. Gramicidin, nonoxynol-9, and EDTA all were found to immobilize sperm, although their effective doses diverged by orders of magnitude. Gramicidin abolished sperm motility within 2 minutes at 4 mcg/ml, but a 50 times higher dose of nonoxynol-9 and 1250 times more EDTA were required to achieve a comparable effect. The combination of 10 ng/ml of gramicidin with 0.1% of EDTA resulted in activity that was four orders of magnitude higher than the optimal combination of nonoxynol-9 with EDTA; sperm penetration into mucus was completely prevented. Moreover, gramicidin inhibited sperm motility without affecting mitochondrial respiratory function or disrupting cell membrane integrity. Quantitative toxicity tests confirmed that gramicidin is a potent spermostatic agent rather than a spermicidal agent. Further development of a gramicidin-EDTA formulation is urged given its potential as a non-toxic topical contraceptive with activity against viral and microbial sexually transmitted diseases.

The significance of ethylenediamine hydrochloride dermatitis caused by a "generic" nystatin-triamcinolone II cream.

Generic Myco-Triacet II Cream would seem to be analogous to Mycolog II Cream. However, Myco-Triacet II Cream still contains the common and potent sensitizer, ethylenediamine hydrochloride, which is no longer present in Mycolog II Cream. This is another instance in which a rose by an other name does not smell as sweet.

An alternative to regular dressings for otitis externa and chronic supperative otitis media?

Otitis externa and chronic otitis media often present to the otolaryngologist with a discharging ear. The conventional method of treatment is to perform regular aural toilet and insert medicated dressings into the external auditory canal. This treatment is either performed by trained nurses or medical staff, but in either case is time consuming. This study compares the efficacy of the above standard regimen with a novel treatment where a single aural toilet is carried out and medicated ointment instilled into the ear. Both regimens were evaluated at three weeks. Our results shows that there was no significant difference between the two treatment regimens with regard to the resolution of either of the conditions studied or the improvement in the symptom status of the patients. On the basis of this it would seem that a single aural toilet and instillation of medicated ointment is a valid treatment option, cuts down hospital attendance and could be performed in the community by general medical practitioners or trained practice nurses.