Effect of low frequency, low amplitude magnetic fields on the permeability of cationic liposomes entrapping carbonic anhydrase:
            <i>I. Evidence for charged lipid involvement</i>

Ramundo-Orlando, Alfonsina; Morbiducci, Umberto; Mossa, Giuseppe; D’Inzeo, G.

doi:10.1002/1521-186x(200010)21:7<491::aid-bem2>3.0.co;2-#

Cited by 27 publications

(19 citation statements)

References 25 publications

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“…Thus, to verify if a dipolar structure of the SA is a plausible target for the interaction of the ELF-EMF with lipid membrane [Ramundo-Orlando et al, 2000], we propose here a simple model for analyzing the behavior of a dipole inserted in a complex environment.…”

Section: Theoretical Studies and Basic Calculationssupporting

confidence: 83%

“…These experimental conditions were used in previous work with CA-loaded liposomes [Ramundo-Orlando et al, 2000]. The results in Table 1 show that the esterase activity of CA was not impaired by ELF magnetic ®elds exposure in this range of frequencies.…”

Section: Resultsmentioning

confidence: 89%

“…We conducted our experiments by using the triaxial exposure system B as previously described [Ramundo-Orlando et al, 2000]. This ELF apparatus provided the control of all the ®eld components.…”

Section: Elf-emfs Exposurementioning

confidence: 99%

“…Furthermore, the deprotonation of SA, induced by increasing the pH of the reaction medium to 8.95, nulli®ed the magnetic ®eld effect. Taken together, these observations link the 7 Hz ®eld effect to the presence of charges of SA on the lipid membrane surface [Ramundo-Orlando et al, 2000].…”

Section: Introductionmentioning

confidence: 99%

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Effect of low frequency, low amplitude magnetic fields on the permeability of cationic liposomes entrapping carbonic anhydrase:II. No evidence for surface enzyme involvement

Ramundo-Orlando¹,

Mattia

Palombo

et al. 2000

Bioelectromagnetics

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Observations recently reported by our group indicate that combined 7 Hz sinusoidal (B(acpeak) = 50 mu T) and parallel static (B(dc) = 50 mu T) magnetic fields can induce a significant increase in diffusion rate of substrate across carbonic anhydrase (CA)-loaded liposomes (DPPC:Chol:SA). A direct involvement of charges of stearylamine (SA) on the lipid membrane surface was also demonstrated. Kinetic studies showed that CA was mainly entrapped in liposomes at 5:3:2 molar ratio, although a small amount (17%) of enzyme was also located on the external surface of these cationic liposomes. In this paper we report steady state kinetic studies on this latter CA after ELF-EMFs exposure. No difference in the apparent K(m) between exposed and sham samples was observed. On the contrary the apparent V(max) was increased by approximately a factor of 2 after field exposure. In spite of the proteolytic digestion of this external CA, a significant increase of enzymatic activity, as a function of increase in the diffusion rate of substrate across the lipid bilayer, was observed in the exposed samples. Based on these results, a conformational change induced by the field on the CA located on the external surface of 5:3:2 liposomes is excluded as an explanation for our previous observations, supporting the primary role of bilayer SA in the interaction with ELF. A model of ELF interaction, based on the Larmor precession theory, explaining the physical phenomenon induced on the dipole of SA has been developed.

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Section: Theoretical Studies and Basic Calculationssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 89%

Section: Elf-emfs Exposurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of low frequency, low amplitude magnetic fields on the permeability of cationic liposomes entrapping carbonic anhydrase:II. No evidence for surface enzyme involvement

Ramundo-Orlando¹,

Mattia

Palombo

et al. 2000

Bioelectromagnetics

Self Cite

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show abstract

“…However, Essence of performing such this study refers to researches done by Desai et al [11] and Mathie et al [12] and Ramundo et al [13] which investigated effects of the radiations on intra membrane structures like proteins and ion channels. This study showed dis-compaction and non uniformity of intranuclear chromatin and its incongruity and heterogenic feature ( Figure 1H) that according to De Iuliis [14] and Aitken's [15] results can change the ultra structure of living tissues.…”

Section: Discussionmentioning

confidence: 99%

New Electromagnetic Radiations Effects on Ultra Structure of Adult Bovine Sperm

Heidari¹,

Farhodi²,

Pashaeiahei³

et al. 2014

nova-jmbs

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The increase of electromagnetic radiations in the environment cause to growing public concern on the effects of them on human being health. The main purposes of many studies have recently been on these topics. Here we aimed to evaluate possible effects of electromagnetic radiations on ultra-structure of sperm. A healthy normal Holstein race bovine was selected for study. A total seminal fluid of a normal ejaculation obtained from normal ejaculation was divided equally into two sample groups. First control group (C1) and experimental group which exposed to electromagnetic radiations (E). At the end of test the ultra-structures of the sperms in all specimens was studied using transmission electron microscopy. Ultra structural changes were observed in the experimental groups comparing to control group (C1). Our data suggest that, electromagnetic radiation have harmful effects on ultra-structure of bovine sperm and is a potential factor which can result in short term dysfunction of sperm in the various stages of fertilization. These effects may be observed later in life.

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Enzyme Immobilization by Microencapsulation: Methods, Materials, and Technological Applications

Rother

Nidetzky

2014

Encyclopedia of Industrial Biotechnology

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Microencapsulation as a major technique of enzyme immobilization is reviewed. Fabrication of enzyme‐containing microcapsules is broadly categorized according to whether a semipermeable membrane coating or a porous polymeric network structure is primarily responsible for enclosure of enzymes within the internal microcapsule phase. Microcapsules are mostly spherical with diameters usually in the micro‐ to millimeter range and exhibit core‐shell structures of variable complexity. Liposomes and vesicles formed from amphiphilic (co)‐polymers (polymersomes) are widely used to prepare membrane‐coated microcapsules. Hydrogels, sol–gels and other organic–inorganic hybrid materials, or layer‐by‐layer structures made through controlled assembly of polyelectrolytes are used to prepare microcapsules composed of internal polymeric networks. Method combination where polymeric network microcapsules are coated with a suitable membrane to generate tailored core‐shell structures is also used for enzyme encapsulation. Advances in the material sciences contribute to the development of microcapsules with improved properties such as enhanced morphological stability, reduced enzyme leakage, and designed physicochemical permeability and enzyme biocompatibility. Soluble enzymes, but also enzyme aggregates and other insoluble enzyme preparations, are encapsulated. Multienzyme microcapsules are interesting small‐scale bioreactors for confined and even compartmentalized cascade biotransformation. Techniques of microcapsule preparation are described, and applications of microencapsulated enzymes in biotechnology and biomedicine are discussed.

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Effect of low frequency, low amplitude magnetic fields on the permeability of cationic liposomes entrapping carbonic anhydrase: I. Evidence for charged lipid involvement

Cited by 27 publications

References 25 publications

Effect of low frequency, low amplitude magnetic fields on the permeability of cationic liposomes entrapping carbonic anhydrase:II. No evidence for surface enzyme involvement

Effect of low frequency, low amplitude magnetic fields on the permeability of cationic liposomes entrapping carbonic anhydrase:II. No evidence for surface enzyme involvement

New Electromagnetic Radiations Effects on Ultra Structure of Adult Bovine Sperm

Enzyme Immobilization by Microencapsulation: Methods, Materials, and Technological Applications

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