Aspectos fundamentais no desenvolvimento de sistemas microemulsionados contendo anfotericina B para uso oftálmico

As occurs with a number of drugs, the bioavailability of amphotericin B (AmB) used to treat fungal infections by the ocular route remains a great challenge to research scientists. In fact, the poor bioavailability of AmB is due mainly to the corneal barrier, which leads to a precorneal loss and consequent decrease in the absorption of this drug into the intraocular tissues. The toxicity associated with this molecule, together with its poor ability to penetrate the intact corneal epithelium, also represents a major drawback to its clinical use. New effective and safe drug vehicles for ocular delivery of AmB are therefore urgently needed. Microemulsions (MEs) seem to be an interesting system, owing to their transparent appearance, thermodynamic stability and favorable viscosity. Knowledge of the process of formation of AmB-containing MEs, as well as a good understanding of the physical chemistry of such systems, would provide reliable information on the best conditions for the use of these systems as eye drops. The goal of this research was thus to make an approach to this subject by reviewing the main studies on the use of MEs as delivery systems for AmB in topical eye treatment.

Statnote 30 : The one-way analysis of variance (ANOVA):fixed effects model

In Statnote 9, we described a one-way analysis of variance (ANOVA) ‘random effects’ model in which the objective was to estimate the degree of variation of a particular measurement and to compare different sources of variation in space and time. The illustrative scenario involved the role of computer keyboards in a University communal computer laboratory as a possible source of microbial contamination of the hands. The study estimated the aerobic colony count of ten selected keyboards with samples taken from two keys per keyboard determined at 9am and 5pm. This type of design is often referred to as a ‘nested’ or ‘hierarchical’ design and the ANOVA estimated the degree of variation: (1) between keyboards, (2) between keys within a keyboard, and (3) between sample times within a key. An alternative to this design is a 'fixed effects' model in which the objective is not to measure sources of variation per se but to estimate differences between specific groups or treatments, which are regarded as 'fixed' or discrete effects. This statnote describes two scenarios utilizing this type of analysis: (1) measuring the degree of bacterial contamination on 2p coins collected from three types of business property, viz., a butcher’s shop, a sandwich shop, and a newsagent and (2) the effectiveness of drugs in the treatment of a fungal eye infection.

Fungal infection of the eye (ocular mycosis)

Although not as important as bacteria or viruses as a cause of eye infection, a large number of fungal species have now been recorded in association with the eye. In addition, several species have been implicated as a cause of eye infection (‘ocular mycosis’) and some may even cause life-threatening conditions. Ocular mycoses are being reported more frequently as a consequence of new medical practice and the increased numbers of immuno-compromised patients in the population, e.g., patients receiving radiation treatment or chemotherapy. This article describes the most common conditions caused by fungi which can affect the different structures of the eye, the importance of fungal contamination of materials as a source of eye infection, and the methods available for treatment.

The microbiology of the eye

Infection of the external structures of the eye is one of the commonest types of eye disease worldwide. In addition, although relatively impermeable to microorganisms, infection within the eye can result from trauma, surgery or systemic disease. This article reviews the general biology of viruses, bacteria, fungi and protozoa and the major ocular infections that they cause. In addition, the effectiveness of the various antimicrobial agents in controlling ocular disease is discussed. Because of changes in the normal ocular flora, continuous monitoring of the microbiology of the eye will continue to be important in predicting future types of eye infection. Basic research is also needed into the interactions of microbes at the ocular surface. There is increasing microbial resistance to the antimicrobial agents used to treat ocular infections and hence, new antimicrobial agents will continue to be needed together with new methods of drug delivery to increase the effectiveness of existing antimicrobial agents.

Bacteria and the eye

Bacteria are minute unicellular organisms present in abundance in air, water, soil and food and in association with the human body. The majority of bacteria are harmless to humans while a few are useful and have been exploited in, for example, the manufacture of dairy products. However, bacteria are also pathogenic and those include some of the most important human infections such as typhoid, syphilis and tuberculosis. A few bacteria are especially important to optometrists because they are associated with ocular disease, either by causing a primary eye infection or because there are ocular complications of a systemic bacterial infection.

Viruses and the eye

About 60% of human infections diseases are caused by viruses,including such important diseases as AIDS, polio, rabies and certain forms of cancer. A few groups of viruses are important to optometrists because they either cause a primary eye infection or a systemic viral infection with ocular complications.

Pathogenicity of Metarhizium anisopliae towards Rhipicephalus (Boophilus) microplus under laboratory and field conditions

Metarhizium anisopliae is one of the most studied agents of biological control of several arthropod plagues, including the cattle tick Rhipicephalus (Boophilus) microplus. Studies have been conducted to assess the fungal complex infection process towards its hosts. To accomplish that, mutant strains overexpressing or lacking assumed determinant genes for the process were constructed over the years. A fundamental experiment to demonstrate a particular gene or set of genes participation is the bioassay. The comparison of bioassays using wild and engineered strains is an essential tool to affirm a given gene is crucial in the process. Therefore, the in vitro bioassays should mimic the results obtained in tests under field conditions. In this study, tests under laboratory and filed conditions were done and a correlation analysis was performed in order to statistically validate in vitro bioassays. Tick egg laying, larvae hatching and host mortality were recorded in each experiment through 21 days, both under laboratory and field conditions. In all cases, M. anisopliae treatments were statistically different from the control treatments. A linear regression analysis was performed between the cases. Laboratory results showed a statistically significant correlation with the field conditions using the Pearson's Correlation Test (P < 0.01 host mortality - 0.969, tick egg laying - 0.977 and larvae hatching - 0.956). These results legitimize the in vitro bioassays and, therefore, constitute them as a valid tool for studying this fungus behavior, so they can be used to infer M. anisopliae response towards R. (Boophilus) microplus.

Altered Behavior in Bats Affected by White-Nose Syndrome

WNS-affected bats did so over similar time frames as WNSunaffected bats. The behaviors of bats with WNS did not change as drastically as expected. Thereseems to be little to no effect on their ability to fly/forage until much later stages of the disease when they are likely near death. WNS-affected bats are grooming more which could be altering the way they use energy reserves during hibernation possibly leading tostarvation and eventually death. The decreased likelihood of arousals in response to external cues may be the result of spending more energy during previous and increasingly frequent arousals. While it is clear that WNS does result in changes in behavior whether these changes are directly in response to fungal skin infection or to some other component of the syndrome such as decreased energy availability or loss of homeostasis is unknown. bat behavior, white-nose syndrome, behavior, video surveillance, arousal patterns White-Nose Syndrome (WNS) is a disease of hibernating bats caused by the fungal pathogen Geomyces destructans. The fungus, which was first noted in 2006, invades bats wings and other exposed membranes, eventually resulting in death. Researchers have yet to understand many aspects of this disease, including basic etiology and epidemiology. There is also a lack of information on how fungal infection may change the behavior of healthy bats during hibernation or how changes in behavior may influence disease progression. Based upon the physiological changes that are known to occur in affected bats, and upon anecdotal observations of aberrant behavior in these bats, I hypothesized that WNS would significantly change the behavior of the little brown myotis (Myotis lucifugus). My research examined the behavior of hibernating bats during arousals from torpor. I compared WNS-affected and unaffected bats, in the field and incaptivity, using motion-sensitive infrared cameras. Flight maneuverability and echolocation were also tested between WNS-affected and unaffected bats during arousalsfrom hibernation to detect changes in the bats' ability to perform basic locomotion or potentially catch insect prey. Lastly, hibernating bats were artificially disturbed and theirarousal patterns were monitored to examine changes in the response to external stimuli between WNS-affected and unaffected bats.Bats with WNS groomed for longer periods of time after arousing from torpor, both in the field and in captivity. They also engaged in longer periods of any sort of activity during these arousals. There were no changes in acoustical signaling during flight tests and changes in flight maneuverability were only found in bats were seen staging" near the entrance of the mine which is itself a unique behavior exhibited by affected bats. At this point these bats were likely near death and could barely fly at all. In response toexternal stimuli bats with WNS were less likely to arouse than unaffected bats. However when they did arouse WNS-affected bats did so over similar time frames as WNSunaffected bats. The behaviors of bats with WNS did not change as drastically as expected. Thereseems to be little to no effect on their ability to fly/forage until much later stages of the disease when they are likely near death. WNS-affected bats are grooming more which could be altering the way they use energy reserves during hibernation possibly leading tostarvation and eventually death. The decreased likelihood of arousals in response to external cues may be the result of spending more energy during previous and increasingly frequent arousals. While it is clear that WNS does result in changes in behavior whetherthese changes are directly in response to fungal skin infection or to some other component of the syndrome such as decreased energy availability or loss of homeostasis is unknown."

Montague, Abigale, autographed letter signed to [ ] Barnerd, 1 side (2 pages), circa 1663 July

Correspondence entreating "Sister Barnerd" in Hartford, Connecticut, to speak to John Winthrop about an eye infection that afflicted Montague's daughter.

A survey of possible associations between preharvest environment conditions and postharvest rejections of cut freesia flowers

Botrytis cinerea is the major pathogen infecting cut freesia flowers. Flecking symptoms on petals caused by this fungus result in postharvest rejections and substantial economic loss to both growers and sellers. In a limited survey for industry, numbers of freesia stems sent from a specialist grower in The Netherlands and rejected at a cut flower wholesaler in the United Kingdom were documented. Relationships between preharvest environment conditions in Holland that may predispose flowers to infection and postharvest freesia rejection levels in the United Kingdom due to B. cinerea flecking symptom expression are reported. Freesia rejections peaked during spring and, to a lesser degree, autumn periods. However, no clear correlations between preharvest growing environment conditions (e.g. 3-day means for temperature preceding harvest) and postharvest rejection frequency (%) could be discerned. Thus, sporadic freesia rejections in the United Kingdom were probably attributable either to other unresolved variables during the pre- (e.g. infection pressure) and/or postharvest (e.g. condensation events) phases or to interactions among predisposing variables.

A randomised controlled study of the efficacy of hypromellose and Lacri-Lube combination versus polyethylene/Cling wrap to prevent corneal epithelial breakdown in the semiconscious intensive care patient

Objective. To compare the efficacy of two forms of eye care (hypromellose and Lacri-Lube combination vs polyethylene/Cling wrap covers) for intensive care patients. Design. Randomised-controlled trial. Setting. University affiliated, tertiary referral hospital. Patients and participants. One hundred ten patients with a reduced or absent blink reflex were followed through until they regained consciousness, were discharged from the facility during study enrolment, died or developed a positive corneal ulcer or eye infection. Interventions. All patients received standard eye cleansing every 2 h. In addition to this, group one (n=60) received a treatment combining hypromellose drops and Lacri-Lube (HL) to each eye every 2 h. Group two (n=50) had polyethylene covers only placed over the eye to create a moisture chamber. Measurements and results. Corneal ulceration was determined using corneal fluorescein stains and mobile slit lamp evaluation, performed daily. No patients had corneal ulceration in the polyethylene cover group, but 4 patients had corneal ulceration in the HL group. Conclusions. Polyethylene covers are as effective as HL in reducing the incidence of corneal damage in intensive care patients.

Health beliefs affect the correct replacement of daily disposable contact lenses:predicting compliance with the Health Belief Model and the Theory of Planned Behaviour

Purpose: To assess the compliance of Daily Disposable Contact Lenses (DDCLs) wearers with replacing lenses at a manufacturer-recommended replacement frequency. To evaluate the ability of two different Health Behavioural Theories (HBT), The Health Belief Model (HBM) and The Theory of Planned Behaviour (TPB), in predicting compliance. Method: A multi-centre survey was conducted using a questionnaire completed anonymously by contact lens wearers during the purchase of DDCLs. Results: Three hundred and fifty-four questionnaires were returned. The survey comprised 58.5% females and 41.5% males (mean age 34. ±. 12. years). Twenty-three percent of respondents were non-compliant with manufacturer-recommended replacement frequency (re-using DDCLs at least once). The main reason for re-using DDCLs was "to save money" (35%). Predictions of compliance behaviour (past behaviour or future intentions) on the basis of the two HBT was investigated through logistic regression analysis: both TPB factors (subjective norms and perceived behavioural control) were significant (p. <. 0.01); HBM was less predictive with only the severity (past behaviour and future intentions) and perceived benefit (only for past behaviour) as significant factors (p. <. 0.05). Conclusions: Non-compliance with DDCLs replacement is widespread, affecting 1 out of 4 Italian wearers. Results from the TPB model show that the involvement of persons socially close to the wearers (subjective norms) and the improvement of the procedure of behavioural control of daily replacement (behavioural control) are of paramount importance in improving compliance. With reference to the HBM, it is important to warn DDCLs wearers of the severity of a contact-lens-related eye infection, and to underline the possibility of its prevention.

Dry eye disease caused by viral infection: review

Dry eye disease and ocular surface disorders may be caused or worsened by viral agents. There are several known and suspected virus associated to ocular surface diseases. The possible pathogenic mechanisms for virus-related dry eye disease are presented herein. This review serves to reinforce the importance of ophthalmologists as one of the healthcare professional able to diagnose a potentially large number of infected patients with high prevalent viral agents.

Restoration of Pattern Recognition Receptor Costimulation to Treat Chromoblastomycosis, a Chronic Fungal Infection of the Skin

Chromoblastomycosis is a chronic skin infection caused by the fungus Fonsecaea pedrosoi. Exploring the reasons underlying the chronic nature of F. pedrosoi infection in a murine model of chromoblastomycosis, we find that chronicity develops due to a lack of pattern recognition receptor (PRR) costimulation. F. pedrosoi was recognized primarily by C-type lectin receptors (CLRs), but not by Toll-like receptors (TLRs), which resulted in the defective induction of proinflammatory cytokines. Inflammatory responses to F. pedrosoi could be reinstated by TLR costimulation, but also required the CLR Mincle and signaling via the Syk/CARD9 pathway. Importantly, exogenously administering TLR ligands helped clear F. pedrosoi infection in vivo. These results demonstrate how a failure in innate recognition can result in chronic infection, highlight the importance of coordinated PRR signaling, and provide proof of the principle that exogenously applied PRR agonists can be used therapeutically.