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N-Methyl-N-D-fructosyl amphotericin B methyl ester (MF-AME), a novel antifungal agent of low toxicity: Monomer/micelle control over selective toxicity.

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Cybulska B., Gadomska I., Mazerski J., Grzybowska J., Borowski E., Cheron M., Bolard J.
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2000
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vol. 47
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issue 1
121-131
EN
Rational chemical modification of amphotericin B (AMB) led to the synthesis of sterically hindered AMB derivatives. The selected optimal compound, N-methyl- N-D-fructosyl amphotericin B methyl ester (MF-AME) retains the broad spectrum of antifungal activity of the parent antibiotic, and exhibits a two orders of magnitude lower toxicity in vivo and in vitro against mammalian cells. Comparative studies of MF-AME and AMB comprising the determination of the spectroscopic properties of monomeric and self-associated forms of the antibiotics, the investigation of the influence of self-association on toxicity to human red blood cells, and of the antibiotic-sterol interaction were performed. On the basis of the results obtained it can be assumed that the improvement of the selective toxicity of MF-AME could in part be a consequence of the diminished concentration of water soluble oligomers in aqueous medium, and the better ability to differentiate between cholesterol and ergosterol.
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Comparative studies on cell stimulatory, permeabilizing and toxic effects induced in sensitive and multidrug resistant fungal strains by amphotericin B (AMB) and N-methyl-N-D-fructosyl amphotericin B methyl ester (MFAME).

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Szlinder-Richert J., Cybulska B., Grzybowska J., Borowski E., Prasad R.
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2000
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vol. 47
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issue 1
133-140
EN
N-Methyl-N-D-fructosyl-amphotericin B methyl ester (MFAME) is a new derivative of amphotericin B, which is characterised by low toxicity to mammalian cells and good solubility in water of its salts. The antifungal activity and effects of MFAME towards Candida albicans and Saccharomyces cerevisiae multidrug resistant MDR(+) and sensitive MDR(-) strains was compared with those of parent compound. The results obtained indicate that MDR(+) S. cerevisiae was sensitive to MFAME as well as to AMB. MFAME exhibited the same effects on fungal cells studied as parent antibiotic. The two antibiotics, depending on the dose applied induced cell stimulation, K+ efflux, and/or had a toxic effect.
3
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Comparative in vitro studies on liposomal formulations of amphotericin B and its derivative, N-methyl-N-D-fructosyl amphotericin B methyl ester (MFAME).

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Cybulska B., Kupczyk K., Szlinder-Richter J., Borowski E.
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2002
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vol. 49
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issue 1
67-75
EN
N-Methyl-N-D-fructosyl amphotericin B methyl ester (MFAME) is a semisynthetic derivative of the antifungal antibiotic amphotericin B (AMB). In contrast to the parent antibiotic, the derivative is characterised by low toxicity to mammalian cells and good solubility in water of its salts. Comparative studies on biological properties of free MFAME, AMB and their liposomal formulations were performed. To obtain liposomal forms, the antibiotics were incorporated into small unilamellar vesicles composed of dimyristoyl phosphatidylcholine (DMPC) and DMPC:cholesterol or ergosterol, 8:2 molar ratio. The effectivity of the liposomal and free forms of AMB and MFAME were compared by determination of fungistatic and fungicidal activity against Candida albicans ATCC 10261, potassium release from erythrocytes, and haemolysis. The results obtained indicate that in contrast to AMB, incorporation of MFAME into liposomes did not further improve its selective toxicity. Studies on the antagonistic effect of ergosterol and cholesterol on the antifungal activity of the antibiotics indicated that sterol interference was definitely less pronounced in the case of MFAME than in the case of AMB.
4
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Wiązanie amfoterycyny B do upigmentowanych grzybów mikroskopowych Cladosporium cladosporioides

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Witoszyńska T., Kulik M., Buszman E., Trzcionka J.
Annales Academiae Medicae Silesiensis
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2012
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vol. 66
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issue 2
34-38
EN
BACKGROUND Dark pigmented microscopic fungi Cladosporium cladosporioides can lead to infection in immunocompromised patients. Melanin biopolymers present in the cell wall protect mycelium and are able to bind diff erent chemicals, including drugs. The aim of this work was to examine the binding capacity of antifungal antibiotic amphotericin B to crude mycelium of Cladosporium cladosporioides, melanin isolated from mycelium and to synthetic DOPA-melanin. MATERIAL AND METHODS Pigmented soil fungi Cladosporium cladosporioides were cultured in the standard liquid medium. Natural melanin was isolated from dry mycelium by acid hydrolysis. Synthetic DOPA-melanin was formed by oxidative polymerization of L-DOPA. Samples of dry mycelium and melanins were complexed with diff erent concentrations of amphotericin B using diff erent times of incubation. The amounts of drug bound to mycelium and to melanins were determined by the use of UV-VIS spectrophotometric method. RESULTS It has been demonstrated that amphotericin B forms complexes with Cladosporium cladosporioides mycelium as well as with melanin isolated from mycelium and with synthetic DOPAmelanin. The amounts of drug bound to melanins increase with increasing initial antibiotic concentration and prolongation of incubation time. CONCLUSION The ability of amphotericin B to form complexes with melanin may be one of the reasons of decreased melanin protection in relation to Cladosporium cladosporioides mycelium.
PL
WSTĘP Ciemno upigmentowane grzyby mikroskopowe Cladosporium cladospo- rioides mogą wywoływać zakażenia, szczególnie u osób z obniżoną odpornością organizmu. Grzyby te w swojej ścianie komórkowej zawierają biopolimery melaninowe ochraniające grzybnię, zdolne do wiązania różnych związków chemicznych, w tym leków. Celem pracy była ocena zdolności wiązania antybiotyku przeciwgrzybiczego amfoterycyny B do grzybni Cladosporium cladosporioides, melaniny wyizolowanej z grzybni i do syntetycznej DOPA-melaniny. MATERIAŁ I METODY Upigmentowane grzyby glebowe Cladosporium cladosporioides hodowano w płynnej pożywce standardowej. Melaninę naturalną izolowano z grzybni metodą hydrolizy kwaśnej. Syntetyczną DOPA-melaninę uzyskano w wyniku reakcji oksydacyjnej polimeryzacji L-DOPA. Próbki melanin i grzybni kompleksowano z roztworami amfoterycyny B o różnych stężeniach, stosując różne czasy inkubacji. Do oznaczenia ilości leku związanego z grzybnią i melaninami zastosowano technikę spektrofotometrii UV-VIS. WYNIKI Wykazano, że amfoterycyna B tworzy kompleksy z grzybnią Cladospo- rium cladosporioides, z melaniną wyizolowaną z grzybni i z syntetyczną DOPA-melaniną. Ilości leku związanego z melaninami zwiększają się wraz ze wzrostem stężenia wyjściowego antybiotyku i wydłużaniem czasu inkubacji. WNIOSKI Silne oddziaływanie amfoterycyny B z melaninami może obniżać funkcje ochronne melanin w stosunku do grzybni Cladosporium cladosporioides.
5
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Nasal Mucormycosis: Our experience with 24 cases

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Bakshi S. S., Das S., Ramesh S., Gopalakrishnan S.
Otolaryngologia Polska
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2020
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vol. 74(4)
37-40
EN
Background: Mucormycosis is a rare fungal infection affecting people with impaired immunity. The aim of this study is to shed light on the epidemiology, incidence, and outcome of patients with mucormycosis hospitalized at a tertiary care center in Pondicherry. Methods: We conducted a retrospective chart review between January 2008 and January 2018. All patients with proven or probable mucormycosis were included. Results: A total of 24 patients were included. Their median age was 49 years and the majority were males. Comorbidities included mainly hematologic malignancy and diabetes mellitus. A liposomal amphotericin B formulation alone or in combination with other antifungals was used as a first line agent in all patients. Conclusion: The incidence of mucormycosis has significantly increased over the past 10 years at our institution, most likely due to increased risk factors.
6
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Nasal Mucormycosis: Our experience with 24 cases

75%
Bakshi S. S., Das S., Ramesh S., Gopalakrishnan S.
Polish Journal of Otolaryngology
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2020
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vol. 74
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issue 4
37-40
EN
Background: Mucormycosis is a rare fungal infection affecting people with impaired immunity. The aim of this study is to shed light on the epidemiology, incidence, and outcome of patients with mucormycosis hospitalized at a tertiary care center in Pondicherry. Methods: We conducted a retrospective chart review between January 2008 and January 2018. All patients with proven or probable mucormycosis were included. Results: A total of 24 patients were included. Their median age was 49 years and the majority were males. Comorbidities included mainly hematologic malignancy and diabetes mellitus. A liposomal amphotericin B formulation alone or in combination with other antifungals was used as a first line agent in all patients. Conclusion: The incidence of mucormycosis has significantly increased over the past 10 years at our institution, most likely due to increased risk factors.
7
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Molecular modelling of membrane activity of amphotericin B, a polyene macrolide antifungal antibiotic

75%
Baginski M., Sternal K., Czub J., Borowski E.
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2005
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vol. 52
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issue 3
655-658
EN
Amphotericin B (AmB) is a well known polyene macrolide antibiotic used to treat systemic fungal infections. Despite its toxicity AmB is still regarded as a life-saving drug. The lack of adequate knowledge of the AmB mechanism of action is a serious obstacle to efficient development of new less toxic derivatives. Complementary to various experimental approaches, computational chemistry methods were used to study AmB mechanism of action. A programme lasting for a decade, that was run by our group covered studies of: i) molecular properties of AmB and its membrane targets, ii) structure and properties of AmB membrane channels, and iii) interaction of AmB with the membrane.
8
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Changes in expression of genes related to caspases and BCL-2 family in RPTEC treated with amphotericin B and its modified forms

63%
Gola J. M., Simka K., Strzałka-Mrozik B., Kruszniewska-Rajs C., Gagoś M., Mazurek U.
Annales Academiae Medicae Silesiensis
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2018
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issue 72
62-68
EN
INTRODUCTION: The main limitation of the use of amphotericin B (AmB) – effective in the treatment of systemic fungal infections – is its high toxicity to human cells. The mechanism of AmB toxicity is not clear. Caspase-related and BCL-2 proteins participate in the regulation of apoptosis. Thus, they may be involved in drug toxicity. In this study we evaluated the influence of AmB on the transcriptional activity of genes related to caspases and the BCL-2 family. We also tested the influence of modified forms of AmB: AmB-Cu2+ (the complex with copper(II) ions) and the AmB-ox (oxidized form). MATERIAL AND METHODS: Human RPTECs (Renal Proximal Tubule Epithelial Cells) were treated with AmB, AmB-Cu2+ and AmB-ox. Total RNA was extracted using the phenol-chloroform method. The expression profiles of genes related to caspase activity and BCL-2 were determined using oligonucleotide microarrays (HG-U133A 2.0, Affymetrix). Analysis included 67 ID related to caspases and 32 ID associated with BCL-2, according to the Affymetrix database. RESULTS: The analysis revealed upregulation of the BCL-2 and BCL2L1genes in the cells treated with AmB-Cu2+, in comparison to the control. In both the AmB and AmB-Cu2+ -treated cells, differentiating genes were associated with inflammation and mitophagy activated by intrinsic signals. In the cells treated with AmB-ox, the BCL-2 genes were downregulated. CONCLUSIONS: The results suggest that AmB and AmB-Cu2+ activate genes involved in the regulation of inflam-mation and autophagy induced by intrinsic signals, but overexpression of BCL-2 and BCL2L1 may protect AmB-Cu2+--treated cells from death. In the cells treated with AmB-ox extrinsic signals prevail, indicating the distinct molecular mechanism of its cytotoxicity.
PL
WSTĘP: Głównym ograniczeniem stosowania amfoterycyny B (AmB) – skutecznej w leczeniu grzybic układowych – jest jej wysoka toksyczność wobec komórek ludzkich. Mechanizm cytotoksyczności nie został wyjaśniony. Białka związane z aktywnością kaspaz oraz białka należące do rodziny BCL-2 uczestniczą w regulacji apoptozy, mogą być zatem zaangażowane w procesy odpowiedzialne za toksyczność leku. W pracy oceniono wpływ AmB na aktywność transkrypcyjną genów kodujących białka związane z aktywnością kaspaz oraz białka z rodziny BCL-2. Zbadano również wpływ modyfikowanych form AmB: AmB-Cu2+ (kompleks z jonami miedzi (II)) i AmB-ox (formy utlenione). MATERIAŁ I METODY: Ludzkie komórki RPTECs (Human Renal Proximal Tubule Epithelial Cells) inkubowano z AmB, AmB-Cu2+ i AmB-ox. Całkowity RNA wyekstrahowano metodą fenolowo-chloroformową. Profil ekspresji genów wyznaczono techniką mikromacierzy oligonukleotydowych (HG-U133A 2.0, Affymetrix). Analiza obejmowała 67 ID genów związanych z aktywnością kaspaz i 32 ID geny kodujące białka z rodziny BCL-2, zaproponowane przez bazę Affymetrix. WYNIKI: Analiza wykazała nadekspresję genów BCL-2 i BCL2L1 w komórkach traktowanych AmB-Cu2+, w porównaniu z kontrolą. Zarówno w komórkach traktowanych AmB, jak i AmB-Cu2+ geny różnicujące związane były z za-paleniem i mitofagią aktywowanymi w odpowiedzi na sygnały wewnątrzkomórkowe. W komórkach traktowanych AmB-ox geny z rodziny BCL-2 były wyciszone. WNIOSKI: Wyniki sugerują, że AmB i AmB-Cu2+ aktywują geny zaangażowane w regulację zapalenia i mitofagii aktywowanych sygnałami wewnątrzkomórkowymi, jednak nadekspresja genów BCL-2 i BCL2L1 może chronić komórki traktowane AmB-Cu2+ przed śmiercią. W komórkach traktowanych AmB-ox przeważa sygnał zewnątrzkomórkowy, co wskazuje na odrębny mechanizm cytotoksyczności tej formy antybiotyku.
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