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.

Lactosylated gramicidin-based lipid nanoparticles (Lac-GLN) for targeted delivery of anti-miR-155 to hepatocellular carcinoma

Lactosylated gramicidin-containing lipid nanoparticles (Lac-GLN) were developed for delivery of anti-microRNA-155 (anti-miR-155) to hepatocellular carcinoma (HCC) cells. MiR-155 is an oncomiR frequently elevated in HCC. The Lac-GLN formulation contained N-lactobionyl-dioleoyl phosphatidylethanolamine (Lac-DOPE), a ligand for the asialoglycoprotein receptor (ASGR), and an antibiotic peptide gramicidin A. The nanoparticles exhibited a mean particle diameter of 73 nm, zeta potential of +3.5mV, anti-miR encapsulation efficiency of 88%, and excellent colloidal stability at 4°C. Lac-GLN effectively delivered anti-miR-155 to HCC cells with a 16.1- and 4.1-fold up-regulation of miR-155 targets C/EBPβ and FOXP3 genes, respectively, and exhibited significant greater efficiency over Lipofectamine 2000. In mice, intravenous injection of Lac-GLN containing Cy3-anti-miR-155 led to preferential accumulation of the anti-miR-155 in hepatocytes. Intravenous administration of 1.5 mg/kg anti-miR-155 loaded Lac-GLN resulted in up-regulation of C/EBPβ and FOXP3 by 6.9- and 2.2-fold, respectively. These results suggest potential application of Lac-GLN as a liver-specific delivery vehicle for anti-miR therapy.

Exogenous Cushing's syndrome due to topical corticosteroid application: case report and review literature

Prolonged use of topical corticosteroids causes systemic adverse effects including Cushing's syndrome and hypothalamic-pituitary-adrenal (HPA) axis suppression, which is less common than that of the oral or parenteral route. At least 43 cases with iatrogenic Cushing syndrome from very potent topical steroid usage (Clobetasol) in children and adult have been published over the last 35 years particularly in developing countries. In children group (n = 22), most are infants with diaper dermatitis and two cases who had started topical application at a very early age and died from severe disseminated CMV infection. For the adult group (n = 21), the most common purpose of steroid use was for treatment of Psoriasis. The recovery period of HPA axis suppression was 3.49 ± 2.92 and 3.84 ± 2.51 months in children and adult, respectively. We report on an 8-month-old female infant who developed Cushing's syndrome and adrenal insufficiency after diaper dermatitis treatment through the misuse of Clobetasol without doctor's prescription. Physiologic dose of hydrocortisone was prescribed to prevent an adrenal crisis for 3 months and discontinued when HPA axis recovery was confirmed by normal morning cortisol and ACTH levels.

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.

A blindedin-vitrostudy to compare the efficacy of five topical ear drops in clearing grommets blocked with thick middle ear effusion fluid

OBJECTIVE

To compare the efficacy of 5% NaHCO3, 3% H2O2, Sofradex (dexamethasone sodium metasulphobenzoate 0.05%, framycetin sulphate 0.5%, gramicidin 0.005%), 0.33% acetic acid and 0.9% NaCl eardrops in clearing grommets blocked with harvested thick middle ear effusion fluid.

STUDY DESIGN

A blinded in-vitro study.

SETTING

District general hospital.

PARTICIPANTS

A total of 473 grommets were blocked with freshly harvested unpooled thick middle ear effusion fluid obtained from 68 patients.

MAIN OUTCOME MEASURES

Patency of the grommets before and 7 days after intervention was ascertained by tympanometry and close visual inspection.

RESULTS

Instillation of eardrops leads to a statistically significant increase in the clearance of grommets as compared with not using any drops (chi2 = 14.3, d.f. = 5, P = 0.006). The numbers needed to treat were 2.8 for NaHCO3, 3.2 for 0.9% NaCl, 3.9 for 0.33% acetic Acid, 4.4 for Sofradex and 9.5 for H2O2 eardrops. Pair-wise comparison was only significant for comparison between 5% NaHCO3 and 3% H2O2 eardrops (Bonferroni corrected P = 0.01, odds ratio = 4.3, CI = 1.9-9.9).

CONCLUSIONS

Use of eardrops leads to a clinically and statistically significant increase in the clearance of blocked grommets. Of the five drops used, 5% NaHCO3 was the most efficacious and 3% H2O2 the least efficacious. Limitations of this in-vitro study are recognized and a prospective in-vivo double blind randomized controlled trial is planned.

The use of perioperative SofradexR eardrops in preventing tympanostomy tube blockage: a prospective double-blinded randomized-controlled trial

Around 11-12% of tympanostomy tubes are reported to become blocked by middle ear secretions or blood immediately following surgery, and so no longer function. Many otologists routinely instil an antibiotic and steroid-containing solution at the time of surgery in the belief that this may reduce this complication. The aim of the study was to investigate the efficacy of instilling the antibiotic and steroid-containing solution Sofradex at the time of grommet insertion in preventing grommet blockage. Double-blind randomized-controlled trial, comparing rates of grommet blockage in ears treated with Sofradex drops against control (no drops) in patients undergoing bilateral grommet insertion. Sixty-one pairs of results were obtained. There was a significant difference between the rates of grommet blockage in the two groups. Grommets with Sofradex drops instilled perioperatively were nine times less likely to be blocked than controls [1.6%versus 13.1%, odds ratio (Sofradex/control) = 9.06, 95% confidence interval (CI): 1.04-78.82, P = 0.05]. There was no association between grommet blockage and perioperative bleeding or the nature and presence of middle ear secretions. Sofradex eardrops are effective in reducing the rate of grommet blockage when instilled perioperatively.

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.

Effectiveness of ototopical antibiotics for chronic suppurative otitis media in Aboriginal children: a community-based, multicentre, double-blind randomised controlled trial

OBJECTIVES

To compare the effectiveness of ototopical ciprofloxacin (0.3%; CIP) with framycetin (0.5%), gramicidin, dexamethasone (FGD) eardrops (5 drops twice daily for 9 days) together with povidone-iodine (0.5%) ear cleaning as treatments for chronic suppurative otitis media (CSOM) in Aboriginal children.

DESIGN AND PARTICIPANTS

Aboriginal community-controlled, community-based, multicentre, double-blind, randomised controlled trial in eight Aboriginal Community Controlled Health Services across northern Australia, involving 147 Aboriginal children with CSOM.

MAIN OUTCOME MEASURES

Resolution of otorrhoea (clinical cure), proportion of children with healed perforated tympanic membrane (TM) and improved hearing, 10-21 days after starting treatment.

RESULTS

111 children aged 1-14 years (CIP, 55; FGD, 56) completed treatment. CSOM cures occurred in 64% (CIP, 76.4%; FGD, 51.8%), with a significantly higher rate in the ciprofloxacin group (P = 0.009, absolute difference of 24.6% [95% CI, 15.8%-33.4%]). TM perforation size and the level of hearing impairment did not change. Pseudomonas aeruginosa was the most common bacterial pathogen (in 47.6%), while respiratory pathogens were rare (in 5.7%).

CONCLUSIONS

Twice-daily ear cleaning and topical ciprofloxacin is effective at community-level in achieving cure for CSOM. Healthcare providers to Aboriginal children with CSOM should be given special access to provide ototopical ciprofloxacin as first-line treatment.

Comparison of compliance between topical aural medications

Patients receiving Gentisone HC, Sofradex and Otomize for chronic suppurative otitis media and otitis externa were investigated for compliance of medication. Drops were accurately weighed before and after use so that both the amount used and the expected amount patients should have used could be calculated. The amount used differed statistically from the amount expected for Sofradex (P = 0.0008) but not for Gentisone HC (P = 0.1049) or Otomize (P = 0.7553) when analysed by a Mann-Whitney U-test. There was a trend to overdose with both Sofradex & Gentisone HC. The reason for the differences, we believe, is due to a combination of both differing delivery systems and drop viscosities. Manufacturers need to improve delivery systems so that patients can deliver a reproducible volume of medication each time with ease.

'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.

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.

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.

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.

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).

A cost-benefit analysis of the post-operative use of antibiotic ear drops following grommet insertion

A prospective randomized controlled study was carried out to investigate the effect of prophylactic antibiotic ear drops used for five days after bilateral grommet insertion. The average improvement in the hearing threshold was significantly better in ears in which there was an effusion (16 dB) compared with no effusion (9 dB). The drops had no significant effect upon grommet function at three months measured by blockage rates, extrusion rates or improvement in pure tone audiometry whether or not there was an effusion. The drops were not therefore cost-effective.

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.

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.

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.

Ventilation tubes, swimming and otorrhoea: a New Zealand perspective

OBJECTS

To compare advice given by specialist otolaryngologists to patients following ventilation tube insertion and the management of purulent otorrhoea in these patients.

METHODS

A postal questionnaire was sent to all 59 specialists currently listed in the New Zealand Otolaryngology Specialist Register.

RESULTS

96.5% of specialist otolaryngologists replied, 88% in sufficient detail for analysis in this study. The vast majority (96%) allowed patients to swim with tubes in situ, and all allowed hair washing. Advice for ear protection varied. If otorrhoea develops with ventilation tubes in situ, 90% of specialists advise patients to stop swimming, but allow hair washing to continue with ear protection. Ninety percent of specialists' initial treatment of otorrhoea involves a combination of suction toilet and topical steroid/antibiotic drops.

CONCLUSION

In general, specialist otolaryngologists in New Zealand give similar advice to patients with ventilation tubes. However, the specific methods of ear protection advised when swimming and hair washing varies markedly.

The efficacy of oral cotrimoxazole in the treatment of otitis externa in general practice

AIM

A double-blind, randomised clinical trial was conducted in Queensland general practices to evaluate the efficacy of oral doses of trimethoprim-sulfamethoxazole (cotrimoxazole) as an adjunct to Kenacomb ointment in the treatment of acute diffuse otitis externa.

METHOD

One hundred and five patients with otitis externa agreed to enter the trial; 13 of these had bilateral otitis externa. Six symptoms and signs of otitis externa were rated on a scale of 1 (none) to 5 (severe) and then the scores were averaged to give an index of severity. Swabs from all infected ears were cultured and then the patients were treated with Kenacomb ointment. Patients were randomly assigned to take a five-day course of either oral cotrimoxazole or an oral placebo and were reassessed on Days 2-4 and Days 5-6 after presentation.

RESULTS

The mean duration (+/- standard deviation) of ear pain from the first visit for the cotrimoxazole and placebo groups was 3.1 (+/- 1.5) days and 3.1 (+/- 1.7) days respectively. The mean severity indices (+/- standard deviation) for these groups on presentation were 2.33 (+/- 0.59) and 2.37 (+/- 0.57). The respective reductions in these scores by the second visit were 0.72 and 0.69 and by the third visit 1.10 and 1.05. The principle pathogen isolated was Pseudomonas aeruginosa.

CONCLUSION

This suggests that oral cotrimoxazole is unlikely to be useful as an adjunct to Kenacomb ointment in the treatment of mild to moderate otitis externa.

[Incidence of postoperative bacterial infections after planned intraocular interventions]

Between August 1982 and August 1984 3059 intraocular operations were performed with topical prophylactic antibiotics. Results of conjunctival cultures did not influence the surgical schedule. 8179 intraocular operations were performed between September 1984 and August 1988. An intraocular operation was postponed until conjunctival cultures were negative using topical antibiotics administered at hourly intervals. The rate of postoperative intraocular infections decreased significantly (p less than 0.0001) from 21 (0.69%) of 3059 during the first to 9 (0.11%) of 8179 intraocular operations during the second observation period. In the first period 11 vitrectomies and 2 enucleations due to bacterial endophthalmitis had to be performed. In the second period 2 vitrectomies and no enucleations were necessary (p less than 0.0001). Our results indicate, that decontamination of the conjunctiva may be an import factor for the prevention of postoperative endophthalmitis following elective intraocular surgery.

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.

[Antimicrobial and hemolytic activities of gradex]

Gradex is a polymer preparation resulting from formation of covalent bonds between the molecules of gramicidin S, a polypeptide antibiotic, and dextran, a polymeric carrier. Antimicrobial and hemolytic activities of gradex were studied. It was shown that the antimicrobial activity of gradex was due to the presence of gramicidin S in its composition. The activity level was lower than that of gramicidin S. It was also found that the gradex reduced form in concentrations up to 300 micrograms/ml had practically no hemolytic effect against human erythrocytes. The reduced form of gradex is promising for development of an artificial ++anti-brucellosis vaccine.

[Heavy metal cation-induced increase in the antimicrobial activity of gramicidin S. Increased sensitivity of metal-resistant mutants of Escherichia coli B to the antibiotic]

Gramicidin S response of metal resistant mutants of E. coli B and the effect of concentrations of Cu2+, Ag+, Co2+ and Cd2+ on the growth and sensitivity of E. coli B to cationic antibiotics, i.e. gramicidin S2+ and streptomycin2+, were studied. It was shown that the metal-cumulating mutants of E. coli B with two different mechanisms of cross resistance to Cu2+, Cd2+ and Ag+ had higher sensitivity to gramicidin S than the initial wild type strain of E. coli B. It was found that in the threshold or higher doses the salts of Cu, Ag, Co and Cd increased the gramicidin S antimicrobial action on actively metabolizing cells of E. coli B. Analysis of the experimental data as well as the literature ones suggested that the synergic action of gramicidin S and the heavy metals stemmed from an increase in the cationic conductivity of the cytoplasma membrane modified by the metals in the threshold doses which induced an increase in the transport and accumulation of the cations in the bacterial cells by the electric field gradient (with the negative sign inside). Withdrawal of Ca2+ and Mg2+ from the E. coli outer structures into the cytoplasm impaired the barrier properties of the outer membrane and promoted binding of the gramicidin S cations to the liberated anionic groups of the E. coli outer structures and potentiation of the gramicidin S antimicrobial activity as was shown in our experiments.

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.

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.

Synergistic antifungal activity and reduced toxicity of liposomal amphotericin B combined with gramicidin S or NF

Amphotericin B (AmpB) disrupts membrane integrity by binding to sterols in fungal and mammalian cell membranes. The gramicidins, which form pores in all membranes but exhibit poor antifungal activity, are too toxic to mammalian cells to be used systemically. This study demonstrated synergistic antifungal activity of free and liposomal forms of AmpB when combined with the free and liposomal forms of gramicidin S and gramicidin NF against five Candida strains. In vitro erythrocyte lysis was prevented by using the liposomal forms of all drugs tested alone or in combination. Presumably, AmpB increases accessibility of the fungal cell membrane to the gramicidins, while liposome encapsulation decreases the rate of transfer of the drugs to the mammalian cell membrane. Liposome encapsulation of inactive or toxic drugs, used in combination with liposomal AmpB, may give new life to drugs previously believed to be inactive or too toxic for therapeutic consideration.

A randomized clinical trial of two topical preparations (framycitin/gramicidin and oxytetracycline/hydrocortisone with polymyxin B) in the treatment of external otitis

In a randomized trial, 55 patients with acute external otitis were treated with either topical framycitin/gramicidin (Sofradex) or oxytetracycline/hydrocortisone (Terracortril) with polymyxin B (TPB) ear-drops for 1 week. Staphylococcus aureus and Pseudomonas pyocyanea were the bacteria most frequently found in the ear canal; 78% of the patients were cured. However, no significant differences in therapy were found when either of the preparations was used. S. aureus seemed to be most resistant to treatment, while P. pyocyanea was less of a therapeutic problem. Additionally, previous episodes of external otitis or other skin diseases did not seem to influence any treatment given.

Post-myringotomy care: a prospective study

Children with tympanostomy tubes have always been considered somewhat handicapped in regard to swimming and bathing. Their parents had to maintain constant surveillance to prevent then from getting water in their ears. A prospective study involving more than 1,000 children was conducted between June 1981 and August 1982 on two groups of randomly selected patients to determine the prevalence of suppurative otitis media and its relationship to bathing and swimming. One group had to follow strict rules to prevent water entering the ear (bathing caps, earplugs) whereas the other group was allowed to bathe and swim without any precaution upon the condition of using a polymyxin B/gramicidin ear drop combination at bedtime on the day they swam. The study shows no increase in prevalence of suppurative otitis media in the "open canal" group as compared to the "closed canal" group. Furthermore, the monthly distribution of infections shows a relatively evan distribution throughout the year. This study implies that swimming and bathing are safe for the vast majority of children with tympanostomy tubes and thus simplifies enormously the post-myringotomy care for the child, the parents, and the physician.

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.

Inhibitory effect of gramicidin S on the growth of murine tumor cells in vitro and in vivo

The Effect of gramicidin S (GS), a polypeptide antibiotic, on the growth of murine tumor cells such as allotransplantable sarcoma 180 (S180) and Ehrlich ascites carcinoma (EAC) and Meth A fibrosarcoma (Meth A) was studied. GS inhibited the proliferation of EAC cells in culture and its effect on cell viability was dependent on the concentration of GS. On exposure to GS at concentrations ranging from 1 to 100 micrograms/ml for 10 min, EAC cells lost their transplantability in ddY mice depending on the concentration of GS. In particular, the transplantability of EAC cells was completely missing on exposure to GS at a concentration of 100 micrograms/ml. In the in vivo experiments, a daily intraperitoneal injection of GS exhibited a high inhibitory effect not only on the growth of subcutaneously implanted S180 in ICR mice but on the growth of subcutaneously implanted syngeneic Meth A in BALB/c mice. In the studies using radioactively labeled DNA, RNA and protein precursors, GS at high concentrations inhibited the incorporation of all the precursors into EAC cells.