Limitations of biosurfactant strength produced by bacteria

Biosurfactants which reduce the surface or interfacial tension of liquids and act as emulsifiers, foaming and dispersing agents with low toxicity, are finding increasing applications in biotechnology and driving the search for novel compounds for further exploitation. Potential biosurfactants sourced from bacteria are often selected first by qualitative assessment of surface tension using simple assays such as the drop collapse technique or by quantitative tensiometry measuring air-liquid interfacial tension of cell-free culture supernatants or purified samples, and subsequently tested for appropriate physicalchemical behaviours using a range of application-specific assays. Highly active or strong biosurfactants have been reported to reduce the surface tension of water to approximately 22 – 25 mN.m-1, and show a range of behaviours determined by the choice of conditions (temperature, pH, salt concentration, etc.) used to test particular aqueous-hydrophobic (oil) mixtures. However, recent analyses of biosurfactant strengths using a predictive statistical approach (Individual distribution identification) have shown that it is unlikely that new compounds will be identified able to significantly reduce aqueous surface tensions below 24 mN.m-1. The mechanistic basis of this limit requires an explanation of why stronger compounds are not produced by bacteria, with a limitation of self-harm to producing cells probably the most likely biophysical explanation. However, behavioural analyses using a combination of emulsion, foam stability and oil-dispersion assays indicates high chemical diversity exists amongst biosurfactants exhibiting the strongest levels of activity (24 – 28 mN.m-1), suggesting that bacteria are still likely to provide a rich source of potentially novel compounds for use in biotechnology

Ocular hypotensive effect of fixed-combination brinzolamide/brimonidine adjunctive to a prostaglandin analog: a randomized clinical trial

To determine whether intraocular pressure (IOP) lowering with fixed-combination brinzolamide/brimonidine (BBFC) adjunctive to a prostaglandin analog (PGA) was superior to that of vehicle+PGA in patients with open-angle glaucoma or ocular hypertension who were inadequately controlled with PGA monotherap

Erarbeitung eines Therapiekonzeptes zur Dehnung des Musculus iliopsoas bei Patienten mit Hüftbeugekontraktur unter Zuhilfenahme einer Ankle-Foot-Orthosis in Kombination mit therapiegestütztem Gehen auf dem Laufband

Eine Vielzahl bekannter neuroorthopädischen Erkrankungen wirkt sich beträchtlich auf die kognitiven und motorischen Fähigkeiten des Betroffenen aus und verursacht teils massive pathologische Gangmuster. Für die erforderliche Symptombehandlung gewinnen Laufbandtherapien in der medizinischen Rehabilitation immer mehr an Bedeutung. Während der Erarbeitung der vorliegenden Bachelorarbeit konnten zahlreiche Informationen vom interdisziplinären Team (Arzt, Orthopädietechniker, Therapeuten, Patientin) eingeholt werden, woraus der tatsächliche Umfang und die Wirkungsweise eines auf eine Beispielpatientin mit Hereditärer Spastischer Spinalparalyse angewandten Therapiekonzepts erweitert werden konnte. Auf der Grundlage einer Laufbandtherapie, der Zuhilfenahme einer Knöchel-Fuß-Orthese und des Behandlungskonzeptes (Dehnung des Musculus iliopsoas, kognitive Schulung des Gehens) wurde zusätzlich der interdisziplinäre Erfolg mit den gewonnenen Erkenntnissen betrachtet und auf eine Eignung des Konzeptes zur weiterführenden Validierung verwiesen. Daraus folgend ergab sich die Anfertigung eines möglichen Therapieleitfadens. Es ließ sich zudem eine potentielle Wirksamkeit der Therapie anhand der Beispielpatientin weitestgehend feststellen, jedoch erwies sich der zeitliche und der inhaltliche Umfang des vom Arzt eingangs angenommen Behandlungskonzeptes als unzureichend

Long-Term Incidence And Timing Of Intraocular Hypertension After Intravitreal Triamcinolone Acetonide Injection

Purpose: To describe the long-term incidence and timing of steroid-induced ocular hypertension after intravitreal triamcinolone acetonide (IVTA) therapy. Design: Retrospective case series of 929 eyes of 841 patients. Participants: Patients with a variety of posterior segment disorders in a single group practice. Intervention: Pars plana injection of IVTA. Main Outcome Measures: Intraocular pressure (IOP) and requirement for glaucoma surgery. Results: Overall, 929 eyes received ≥1 injections (mean, 1.6) of 4 mg of IVTA. During a mean follow-up period of 14±6.9 months, the Kaplan-Meier cumulative incidences of IOP elevations \u3e21 mmHg at 6, 12, 18, and 24 months post-injection were 28.2%, 34.6%, 41.2%, and 44.6%, respectively; similarly, the incidences of eyes with IOP measurements \u3e25 mmHg were 14.6%, 19.1%, 24.1%, and 28.2%, respectively. At the same time points, lOP-lowering medications were required byl3.0%, 16.9%, 20.7%, and 24.2% of eyes, respectively. Only 3 eyes (0.3%) required lOP-lowering surgery. Preexisting glaucoma, younger age, and a history of an IOP elevation after a previous IVTA injection were risk factors for IOP elevations after IVTA injection. The minimum and maximum follow-up were 3 weeks and 37 months. The mean rate of attrition in this study was 3% per month. Conclusions: Elevations in IOP after IVTA injection are common. Younger patients and eyes with preexisting glaucoma or a history of a steroid response should be monitored more closely for IOP elevations after IVTA therapy

Limitations of biosurfactant strength produced by bacteria

Biosurfactants which reduce the surface or interfacial tension of liquids and act as emulsifiers, foaming and dispersing agents with low toxicity, are finding increasing applications in biotechnology and driving the search for novel compounds for further exploitation. Potential biosurfactants sourced from bacteria are often selected first by qualitative assessment of surface tension using simple assays such as the drop collapse technique or by quantitative tensiometry measuring air-liquid interfacial tension of cell-free culture supernatants or purified samples, and subsequently tested for appropriate physicalchemical behaviours using a range of application-specific assays. Highly active or strong biosurfactants have been reported to reduce the surface tension of water to approximately 22 – 25 mN.m-1, and show a range of behaviours determined by the choice of conditions (temperature, pH, salt concentration, etc.) used to test particular aqueous-hydrophobic (oil) mixtures. However, recent analyses of biosurfactant strengths using a predictive statistical approach (Individual distribution identification) have shown that it is unlikely that new compounds will be identified able to significantly reduce aqueous surface tensions below 24 mN.m-1. The mechanistic basis of this limit requires an explanation of why stronger compounds are not produced by bacteria, with a limitation of self-harm to producing cells probably the most likely biophysical explanation. However, behavioural analyses using a combination of emulsion, foam stability and oil-dispersion assays indicates high chemical diversity exists amongst biosurfactants exhibiting the strongest levels of activity (24 – 28 mN.m-1), suggesting that bacteria are still likely to provide a rich source of potentially novel compounds for use in biotechnology