Radiolytic studies of cefozopran hydrochloride in the solid state

Background: The radiation sterilization is one of the best methods for sterilizing vulnerable degradation drugs like cefozopran hydrochloride. Results: Chemical stability of radiosterylized cefozopran hydrochloride, was confirmed by spectrophotometric and chromatographic methods. EPR studies showed that radiation has created some radical defects whose concentration was no more than several dozen ppm. The antibacterial activity of cefozopran hydrochloride irradiated with a dose of 25 kGy was unaltered for Gram-positive bacteria but changed for two Gram-negative strains. The radiation sterilized cefozopran hydrochloride was not in vitro cytotoxic against human CCD39Lu normal lung fibroblast cell line. Conclusions: Cefozopran hydrochloride in solid state is not resistant to radiation sterilization and this method cannot be used for sterilization of this compound.

New Colonoscopy Devices to Improve Colon Neoplasm Detection / 대한소화기학회지

Early detection and removal of adenomatous polyps can prevent the development of colorectal cancer. However, it is fairly common—up to 20%—for polyps to be undetected in a colonoscopy due to poor visualization of the proximal aspect of colonic folds and anatomical flexures. To overcome these limitations, many new endoscopes and accessories have been developed. A wide-angle colonoscopy did not improve the detection of adenoma compared with the standard colonoscopy. An extra-wide angle and Retroview colonoscopies showed a significantly lower miss rate of polyps in the colon model. However, clinical trials are mandatory in the future. The recently introduced full spectrum endoscopy system showed a significantly higher adenoma detection rate than the standard forward-viewing colonoscopy. In accessories, The cap-assisted colonoscopy showed only a marginal or no benefit on the detection of polyps and adenomas. In contrast, a colonoscopy with Endocuff, EndoRings, and G-eye have showed significantly lower adenoma miss rates. The Third Eye, which provides additional retrograde viewing, has revealed a significant improvement in the detection of adenoma and polyp. However, the Third Eye Retroscope was limited by its deployment through the working channel of the scope. Recently, the Third Eye Panoramic cap, which was designed to overcome the limitation of the Third Eye Retroscope, was introduced. In the future, this would be needed to evaluate the effectiveness, efficiency and safety for these new colonoscopies and accessories.

Estudos biofísicos e de atividade de peptídeos correspondentes ao N-terminal das toxinas esticolisinais I e II - contribuição para a elucidação do mecanismo de ação / Biophysical and activity studies of peptides corresponding to the N-termini of sticholysins I and II - a contribution to the elucidation of the toxins' mechanism of action

Esticolisinas I e II, citolisinas purificadas da anêmona marinha Stichodactyla helianthus, agem lisando membranas biológicas e modelo. O mecanismo de ação proposto consiste na formação de um poro toroidal com o envolvimento do domínio N-terminal. Diferentes aspectos da interação entre peptídeos derivados do N-terminal das toxinas (StI1-31 and StI12-31 SELAGTIIDGASLTFEVLDKVLGELGKVSRK, e StII1-30 and StII11-30 ALAGTIIAGASLTFQVLDKVLEELGKVSRK) com membranas modelo - micelas e bicamadas - foram estudados com o objetivo de contribuir para a elucidação do mecanismo de ação das toxinas em nível molecular. O emprego dos peptídeos teve como base a hipótese de que fragmentos proteicos podem ser capazes de mimetizar a estrutura e atividade das proteínas inteiras. O análogo contendo o aminoácido paramagnético TOAC (N-TOAC-StII11-30) também foi estudado. Estudos conformacionais foram realizados empregando-se as técnicas espectroscópicas de dicroísmo circular (CD), ressonância paramagnética eletrônica (EPR) e fluorescência. Foram ainda realizados estudos de predição de estrutura e modelagem molecular. Espectros de CD mostraram que os peptídeos adquirem conformação em α-hélice ao interagir com membranas modelo, de acordo com a conformação observada nessa região para as toxinas. Variando a composição lipídica das membranas modelo estudadas, foi possível investigar a contribuição de forças eletrostáticas de de interações hidrofóbicas para a ligação do peptídeo. Ensaios de supressão de fluorescência de lípidos contendo grupamentos fluorescentes em diferentes posições pelo resíduo paramagnético TOAC e espectros de ressonância paramagnética eletrônica (EPR) permitiram localizar o resíduo TOAC na interface membrana-água, corroborando o modelo proposto do poro toroidal. A análise dos espectros de CD e EPR também permitiu obter as constantes de ligação dos peptídeos com micelas e bicamadas. Os peptídeos também foram capazes de mimetizar as toxinas do ponto de vista funcional, como mostrado por testes de vazamento de carboxifluoresceína e atividade hemolítica. Peptídeos curtos, contendo partes da sequência de StII1-30, sintetizados com o objetivo de examinar uma eventual atividade antimicrobiana, demonstraram baixa atividade, bem como ausência de atividade hemolítica e de toxicidade para células humanas

Sticholysins I and II, cytolysins purified from the sea anemone Stichodactyla helianthus, act by lysing biological and model membranes. The proposed mechanism of action consists in the formation of a toroidal pore with the involvement of the N-terminal domain [1]. Different aspects of the interaction between peptides from the toxins' N-termini (StI1-31 and StI12-31 SELAGTIIDGASLTFEVLDKVLGELGKVSRK, and StII1-30 and StII11-30 ALAGTIIAGASLTFQVLDKVLEELGKVSRK) and model membranes - micelles and bilayers - have been studied to contribute to the elucidation of the toxins mechanism of action at the molecular level. The use of peptides was based on the hypothesis that potein fragments can eventually mimic the structure and activity of the whole protein. An analogue containing the paramagnetic amino acid TOAC (N-TOAC-StII11-30) was also studied. Conformational studies were performed making use of the spectroscopic techniques circular dichroism (CD), electron paramagnetic resonance (EPR), and fluorescence. Studies of structure prediction and molecular modeling were also performed. CD spectra showed that the peptides acquired α-helical conformation upon interaction with model lipid membranes, in agreement with the conformation found for these segments in the whole proteins. Making use of membranes of variable lipid composition, it was possible to assess the contribution of electrostatic and hydrophobic interactions for peptide binding. Fluorescence quenching of labeled lipids by paramagnetic TOAC and EPR spectra allowed us to locate the TOAC residue at the membrane-water interface, corroborating the proposed model of the toroidal pore. The CD and EPR studies also allowed us to obtain the binding constants for the peptide-micelle and peptide-bilayer interaction. The peptides were also capable of mimicking the toxins function, as shown by assays of carboxyfluorescein leakage and hemolytic activity. Short peptides containing parts of StII1-30's sequence were synthesized with the aim of testing their antimicrobial activity. The peptides displayed low antimicrobial activity, as well as lack of hemolytic activity and toxicity against human cells

Reconstructive dosimetry for cutaneous radiation syndrome

According to the International Atomic Energy Agency (IAEA), a relatively significant number of radiological accidents have occurred in recent years mainly because of the practices referred to as potentially high-risk activities, such as radiotherapy, large irradiators and industrial radiography, especially in gammagraphy assays. In some instances, severe injuries have occurred in exposed persons due to high radiation doses. In industrial radiography, 80 cases involving a total of 120 radiation workers, 110 members of the public including 12 deaths have been recorded up to 2014. Radiological accidents in industrial practices in Brazil have mainly resulted in development of cutaneous radiation syndrome (CRS) in hands and fingers. Brazilian data include 5 serious cases related to industrial gammagraphy, affecting 7 radiation workers and 19 members of the public; however, none of them were fatal. Some methods of reconstructive dosimetry have been used to estimate the radiation dose to assist in prescribing medical treatment. The type and development of cutaneous manifestations in the exposed areas of a person is the first achievable gross dose estimation. This review article presents the state-of-the-art reconstructive dosimetry methods enabling estimation of local radiation doses and provides guidelines for medical handling of the exposed individuals. The review also presents the Chilean and Brazilian radiological accident cases to highlight the importance of reconstructive dosimetry.

Characterization and biological activities of extracellular melanin produced by Schizophyllum commune (Fries).

Melanins are enigmatic pigments produced by a wide variety of microorganisms including bacteria and fungi. Here, we have isolated and characterized extracellular melanin from mushroom fungus, Schizophyllum commune. The extracellular dark pigment produced by the broth culture of S. commune, after 21 days of incubation was recovered by hot acid-alkali treatment. The melanin nature of the pigment was characterized by biochemical tests and further, confirmed by UV, IR, EPR, NMR and MALDI-TOF Mass Spectra. Extracellular melanin, at 100 µg/ml, showed significant antibacterial activity against Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae and Pseudomonas fluorescens and antifungal activity against Trichophyton simii and T. rubrum. At a concentration of 50 µg/ml, melanin showed high free radical scavenging activity of DPPH (2,2-diphenyl-1-picrylhydrazyl) indicating its antioxidant potential. It showed concentration dependent inhibition of cell proliferation of Human Epidermoid Larynx Carcinoma Cell Line (HEP-2). This study has demonstrated characterization of melanin from basidiomycetes mushroom fungus, Schizophyllum commune and its applications.

Current status of residency training in laparoscopic surgery in Brazil: a critical review / Situação atual do treinamento de médicos residentes em videocirurgia no Brasil: uma análise crítica

INTRODUCTION: The surgeon's formation process has changed in recent decades. The increase in medical schools, new specialties and modern technologies induce an overhaul of medical education. Medical residency in surgery has established itself as a key step in the formation of the surgeon, and represents the ideal and natural way for teaching laparoscopy. However, the introduction of laparoscopic surgery in the medical residency programs in surgical specialties is insufficient, creating the need for additional training after its termination. OBJECTIVE: To review the surgical teaching ways used in services that published their results. METHODS: Survey of relevant publications in books, internet and databases in PubMed, Lilacs and Scielo through july 2014 using the headings: laparoscopy; simulation; education, medical; learning; internship and residency. RESULTS: The training method for medical residency in surgery focused on surgical procedures in patients under supervision, has proven successful in the era of open surgery. However, conceptually turns as a process of experimentation in humans. Psychomotor learning must not be developed directly to the patient. Training in laparoscopic surgery requires the acquisition of psychomotor skills through training conducted initially with surgical simulation. Platforms based teaching problem solving as the Fundamentals of Laparoscopic Surgery, developed by the American Society of Gastrointestinal Endoscopic Surgery and the Laparoscopic Surgical Skills proposed by the European Society of Endoscopic Surgery has been widely used both for education and for the accreditation of surgeons worldwide. CONCLUSION: The establishment of a more appropriate pedagogical process for teaching laparoscopic surgery in the medical residency programs is mandatory in order to give a solid surgical education and to determine a structured and safe professional activity. .

INTRODUÇÃO: A formação do cirurgião geral vem se modificando nas últimas décadas. O aumento das escolas médicas, as novas especialidades e as modernas tecnologias induzem à reformulação do ensino médico. A residência médica em cirurgia estabeleceu-se como etapa fundamental na formação do cirurgião e surge como a forma ideal e natural para o ensino da videocirurgia. No entanto, a introdução da videocirurgia nos programas de residência médica nas diversas especialidades cirúrgicas é insuficiente, gerando a necessidade de treinamento complementar após o seu término. OBJETIVO: Rever a situação de ensino da videocirurgia em serviços que publicaram seus métodos. MÉTODO: Revisão de conteúdo publicado em livros e na internet considerados relevantes, além de pesquisa nas bases de dados PubMed, Lilacs e Scielo até julho 2014 com os descritores: videocirurgia; simulação; educação médica; aprendizagem; treinamento em cirurgia. RESULTADO: O método de treinamento em programas de residência médica em cirurgia, focado na realização de procedimentos cirúrgicos sob supervisão em pacientes, comprovou sua eficiência na era da cirurgia aberta. No entanto, configura conceitualmente um processo de experimentação em seres humanos. O aprendizado psicomotor não deve e não pode ser desenvolvido diretamente no paciente. A formação em videocirurgia requer a aquisição de habilidades psicomotoras únicas, através de treinamento realizado inicialmente por simulação cirúrgica. Plataformas de ensino baseadas na solução de problemas como o Fundamentals of Laparoscopic Surgery, desenvolvido pela Sociedade Americana de Cirurgia Endoscópica Gastrointestinal e o Laparoscopic Surgical Skills proposto pela Sociedade Europeia de Cirurgia Endoscópica são exemplos que têm sido amplamente utilizados tanto para o ensino como para a acreditação de cirurgiões em todo o mundo. CONCLUSÃO: É necessário o estabelecimento de um processo pedagógico mais adequado para o ensino da videocirurgia ...

Antioxidant effect of 4-nerolidylcatechol and -tocopherol in erythrocyte ghost membranes and phospholipid bilayers

4-Nerolidylcatechol (4-NC) is found in Pothomorphe umbellata root extracts and is reported to have a topical protective effect against UVB radiation-induced skin damage, toxicity in melanoma cell lines, and antimalarial activity. We report a comparative study of the antioxidant activity of 4-NC and α-tocopherol against lipid peroxidation initiated by two free radical-generating systems: 2,2′-azobis(2-aminopropane) hydrochloride (AAPH) and FeSO4/H2O2, in red blood cell ghost membranes and in egg phosphatidylcholine (PC) vesicles. Lipid peroxidation was monitored by membrane fluidity changes assessed by electron paramagnetic resonance spectroscopy of a spin-labeled lipid and by the formation of thiobarbituric acid-reactive substances. When lipoperoxidation was initiated by the hydroxyl radical in erythrocyte ghost membranes, both 4-NC and α-tocopherol acted in a very efficient manner. However, lower activities were observed when lipoperoxidation was initiated by the peroxyl radical; and, in this case, the protective effect of α-tocopherol was lower than that of 4-NC. In egg PC vesicles, malondialdehyde formation indicated that 4-NC was effective against lipoperoxidation initiated by both AAPH and FeSO4/H2O2, whereas α-tocopherol was less efficient in protecting against lipoperoxidation by AAPH, and behaved as a pro-oxidant for FeSO4/H2O2. The DPPH (2,2-diphenyl-1-picrylhydrazyl) free-radical assay indicated that two free radicals were scavenged per 4-NC molecule, and one free radical was scavenged per α-tocopherol molecule. These data provide new insights into the antioxidant capacity of 4-NC, which may have therapeutic applications for formulations designed to protect the skin from sunlight irradiation.

Fucoxanthin Protects Cultured Human Keratinocytes against Oxidative Stress by Blocking Free Radicals and Inhibiting Apoptosis

Fucoxanthin is an important carotenoid derived from edible brown seaweeds and is used in indigenous herbal medicines. The aim of the present study was to examine the cytoprotective effects of fucoxanthin against hydrogen peroxide-induced cell damage. Fucoxanthin decreased the level of intracellular reactive oxygen species, as assessed by fluorescence spectrometry performed after staining cultured human HaCaT keratinocytes with 2',7'-dichlorodihydrofl uorescein diacetate. In addition, electron spin resonance spectrometry showed that fucoxanthin scavenged hydroxyl radical generated by the Fenton reaction in a cell-free system. Fucoxanthin also inhibited comet tail formation and phospho-histone H2A.X expression, suggesting that it prevents hydrogen peroxide-induced cellular DNA damage. Furthermore, the compound reduced the number of apoptotic bodies stained with Hoechst 33342, indicating that it protected keratinocytes against hydrogen peroxide-induced apoptotic cell death. Finally, fucoxanthin prevented the loss of mitochondrial membrane potential. These protective actions were accompanied by the down-regulation of apoptosis-promoting mediators (i.e., B-cell lymphoma-2-associated x protein, caspase-9, and caspase-3) and the up-regulation of an apoptosis inhibitor (B-cell lymphoma-2). Taken together, the results of this study suggest that fucoxanthin defends keratinocytes against oxidative damage by scavenging ROS and inhibiting apoptosis.

Avaliação por ressonância paramagnética eletrônica da concentração de radicais livres gerados em um cimento resinoso dual utilizado na cimentação de um pino de fibra de vidro / Evaluation by electron paramagnetic resonance of the concentration of free radicals generated in a dual resin cement used on the cementing of translucent glass fiber post

Foi analisado por espectro de Ressonância Paramagnética Eletrônica (RPE), a concentração de radicais livres (RL) formados quando da cimentação de pino de fibra de vidro (PFV), com cimento resinoso dual (CRD), bem como a influência da forma anatômica do PFV (cônico ou cilíndrico). A primeira etapa foi composta de 3 grupos, de acordo com o método de cimentação do PFV numa matriz de silicone: G1- CRD fotopolimerizado por 40 segundos, com aparelho fotopolimerizador de diodo emissor de luz (LED), com potência de 1.500mW/cm2, encostado à superfície externa do pino; G2- CRD não recebeu ativação física; G3- tratamento semelhante ao G1, mas com bloqueio da interface pino/silicone. Na segunda etapa, os PFV foram seccionados de forma a obter dois pinos: PFVCl, cilíndrico e PFVCn cônico, de 9,5mm de comprimento cada, cimentadas semelhantemente ao G1. A concentração de radicais livres foi avaliada em: T0-10 minutos após espatulação do cimento e T1-24 horas após, em secções obtidas em diferentes profundidades do PFV. A análise do espectro das ressonâncias indicou que G1 e G3, apresentaram maior CRL. A translucidez do pino não influenciou na concentração de RL em profundidades acima de 12mm. Os pinos cilíndricos apresentaram maior concentração de RL. A concentração de radicais livres é influenciada pelo método de polimerização, bem como pela forma anatômica do PFV; a capacidade de condução da luz pelo PFV não interfere no grau de conversão do CRD nas regiões de maior profundidade.

The free radical concentration (FR) formed during GFP cementation, using dual cure resin cement (DCRC), as well as the influence of the anatomical shape of the GFP (conical or cylindrical), were analyzed by Electron Paramagnetic Resonance (EPR) spectrum. The first stage consisted of 3 groups, according to the GFP cementation method in a silicone matrix: G1- DCRC light cured for 40 seconds, with light emitting diode (LED), with intensity of 1.500mW/cm2 , leaning against the outer surface of the post; G2 - DCRC without light activation; G3- treatment similar to G1, but blocking the post/matrix interface. In the second stage, GFP were sectioned to obtain two sections: PFVCl, cylindrical and PFVCn, conical, 9,5mm in length each, cemented similarly to G1. The FRC was evaluated in: T0-10 minutes after cement's spatulation e T1-24 hours after, in sections obtained from different GFP depths. The resonance spectrum analysis indicated that G1 and G3 had a greater FR concentration. Post translucency did not influenced the FRC at depths greater than 12mm. Cylindrical posts presented greater FRC. The FR concentration is influenced by the polymerization method, as well as the GFP anatomical shape; GFP capacity to conduct light does not interferes in the degree of conversion on DCRC in regions of greater depth.

Electron paramagnetic resonance study of lipid and protein membrane components of erythrocytes oxidized with hydrogen peroxide

Electron paramagnetic resonance (EPR) spectroscopy of spin labels was used to monitor membrane dynamic changes in erythrocytes subjected to oxidative stress with hydrogen peroxide (H2O2). The lipid spin label, 5-doxyl stearic acid, responded to dramatic reductions in membrane fluidity, which was correlated with increases in the protein content of the membrane. Membrane rigidity, associated with the binding of hemoglobin (Hb) to the erythrocyte membrane, was also indicated by a spin-labeled maleimide, 5-MSL, covalently bound to the sulfhydryl groups of membrane proteins. At 2% hematocrit, these alterations in membrane occurred at very low concentrations of H2O2 (50 µM) after only 5 min of incubation at 37°C in azide phosphate buffer, pH 7.4. Lipid peroxidation, suggested by oxidative hemolysis and malondialdehyde formation, started at 300 µM H2O2 (for incubation of 3 h), which is a concentration about six times higher than those detected with the probes. Ascorbic acid and α-tocopherol protected the membrane against lipoperoxidation, but did not prevent the binding of proteins to the erythrocyte membrane. Moreover, the antioxidant (+)-catechin, which also failed to prevent the cross-linking of cytoskeletal proteins with Hb, was very effective in protecting erythrocyte ghosts from lipid peroxidation induced by the Fenton reaction. This study also showed that EPR spectroscopy can be useful to assess the molecular dynamics of red blood cell membranes in both the lipid and protein domains and examine oxidation processes in a system that is so vulnerable to oxidation.

Analysis of arterial spin labeling in 33 patients with hypoxic ischemic encephalopathy / 中华儿科杂志

<p><b>OBJECTIVES</b>To evaluate the diagnostic value of arterial spin labeling (ASL) technology in newborns with hypoxic ischemic encephalopathy (HIE).</p><p><b>METHOD</b>Seven full-term newborn infants without any history of asphyxia and other nervous system diseases were selected as the control and 33 full-term newborn infants were assigned into HIE group. The patients in HIE group were further divided into three subgroups (19 cases of mild, 6 cases of moderate and 8 cases of severe HIE) based on their clinical diagnosis. The control group and HIE group were examined with GE Signa EXCITE HD 3.0T superconducting MRI scanner with a head phase array coil. Both groups were scanned with conventional axial MRI (T1FLAIR, T2WI and T2FLAIR), 1HMRS (PRESS sequence) and ASL (FAIR). Original images of 1HMRS and ASL were processed by Functool software of ADW 4.3 workstation. ASL perfusion images were observed and the signal intensity values of the region of interest (bilateral gray, white matter and basal ganglia) of the two groups were quantitatively measured, and mean value were calculated and compared between groups. Statistical analysis was performed with SPSS 13.0 software, and statistically significant difference was set at P < 0.05.</p><p><b>RESULT</b>The perfusion images of two groups were obtained perfectly. The signal intensity values of bilateral gray, white matter and basal ganglia of control group were 125.34 ± 11.76, 73.42 ± 11.67 and 173.65 ± 15.49, respectively and there was a statistically significant difference between the different areas. The signal intensity values of bilateral gray, white matter and basal ganglia of HIE group were 153.47 ± 11.72, 71.35 ± 10.37 and 217.13 ± 12.51, respectively. There was a statistically significant difference (P < 0.05) in the average signal intensity value of gray matter and basal ganglia, but there were no statistically significant difference (P > 0.05) in white matter between the two groups.</p><p><b>CONCLUSION</b>ASL Perfusion technique can assess HIE comprehensively and accurately. Furthermore, it can evaluate the brain damage of hypoxic ischemia. The results provide a strong basis for clinical treatment.</p>

Using ESR technology observe the change of free radicals in cochlea after acute acoustic trauma / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To observe the changes of free radicals in the cochlea of guinea pigs after noise exposure directly using electron spin resonance (ESR) technology.@*METHOD@#Forty-two guinea pigs as experimental group were given (125 +/- 1) dB SPL noise exposure for 2 hours, and then investigated auditory function immediately, at 2, 6, 12, 24, 48 and 72 hour. After ABR examinations, 21 animals decollated and extracted cochlea immediately and then placed the cochleas to liquid nitrogen for deep freezing and measuring free radicals using ESR technology. Another 21 animals observed hair cells morphology by AgNO3 staining. Meantime, 6 animals without noise exposure were served as negative control group.@*RESULT@#A few free radicals were detected in the cochlea at control group and the relative value of free radicals were (21.68 +/- 1.27) dB SPL. After noise exposure, the relative value of free radicals increased obviously and achieved to the max of (147.01 +/- 4.95) dB SPL at 2 h and gradually decreased near the normal level.@*CONCLUSION@#Free radicals in the cochlea increase evidently and have a concentration-time rule after acute acoustic trauma. The ESR method can be used to examine the content of free radicals in cochlea for its direct, objective and sensitive characters.

Evaluation of antioxidant properties of a new compound, pyrogallol-phloroglucinol-6,6'-bieckol isolated from brown algae, Ecklonia cava

In this study, antioxidant and free radical scavenging activities of the natural antioxidative compound, pyrogallol-phloroglucinol-6,6'-bieckol (PPB) isolated from brown algae, Ecklonia cava was assessed in vitro by measuring the radical scavenging activities (DPPH, alkyl, hydroxyl, and superoxide) using electron spin resonance (ESR) spectrometry, intracellular reactive oxygen species (ROS) scavenging activity, and DNA damage assay. According to the results of these experiments, the scavenging activity PPB against difference radicals was in the following order: DPPH, alkyl, hydroxyl, and superoxide radicals (IC50; 0.90, 2.54, 62.93 and 109.05 microM). The antioxidant activities of PPB were higher than that of the commercial antioxidant, ascorbic acid. Furthermore, PPB effectively inhibited DNA damage induced by H2O2. These results suggest that the natural antioxidative compound, PPB, can be used by the natural food industry.

Modulation of ROS production in human leukocytes by ganglioside micelles

Recent studies have reported that exogenous gangliosides, the sialic acid-containing glycosphingolipids, are able to modulate many cellular functions. We examined the effect of micelles of mono- and trisialoganglioside GM1 and GT1b on the production of reactive oxygen species by stimulated human polymorphonuclear neutrophils using different spectroscopic methods. The results indicated that exogenous gangliosides did not influence extracellular superoxide anion (O2.-) generation by polymorphonuclear neutrophils activated by receptor-dependent formyl-methionyl-leucyl-phenylalanine. However, when neutrophils were stimulated by receptor-bypassing phorbol 12-myristate 13-acetate (PMA), gangliosides above their critical micellar concentrations prolonged the lag time preceding the production in a concentration-dependent way, without affecting total extracellular O2.- generation detected by superoxide dismutase-inhibitable cytochrome c reduction. The effect of ganglioside GT1b (100 µM) on the increase in lag time was shown to be significant by means of both superoxide dismutase-inhibitable cytochrome c reduction assay and electron paramagnetic resonance spectroscopy (P < 0.0001 and P < 0.005, respectively). The observed phenomena can be attributed to the ability of ganglioside micelles attached to the cell surface to slow down PMA uptake, thus increasing the diffusion barrier and consequently delaying membrane events responsible for PMA-stimulated O2.- production.

Cyclic AMP prolongs graft survival by suppressing apoptosis and inflammatory gene expression in acute cardiac allograft rejection

This study was designed to investigate the effects of cAMP on immune regulation and apoptosis during acute rat cardiac allograft rejection. We found that the production of immune markers such as inflammatory cytokines (IL-1beta, IL-6, and TNF-alpha), iNOS expression, and nitric oxide (NO) production, was significantly increased in the blood and transplanted hearts of allograft recipients, but not of isograft controls. These increases were effectively suppressed by the administration of the membrane permeable cAMP analog dibutyryl cAMP (db-cAMP). Administration of db-cAMP reduced allograft-induced elevation of several biochemical markers, such as adhesion molecule expression, iron-nitrosyl complex formation, caspase-3 activation, and apoptotic DNA fragmentation in an animal model. Furthermore, treatment of allograft recipients with db-cAMP prolonged median graft survival to 11 days compared with a median graft survival time of 8 days in saline-treated allograft recipients. These results suggest that db-cAMP exerts a beneficial effect on murine cardiac allograft survival by modulating allogeneic immune response and cytotoxicity.

Structural properties of lipid reconstructs and lipid composition of normotensive and hypertensive rat vascular smooth muscle cell membranes

Multiple cell membrane alterations have been reported to be the cause of various forms of hypertension. The present study focuses on the lipid portion of the membranes, characterizing the microviscosity of membranes reconstituted with lipids extracted from the aorta and mesenteric arteries of spontaneously hypertensive (SHR) and normotensive control rat strains (WKY and NWR). Membrane-incorporated phospholipid spin labels were used to monitor the bilayer structure at different depths. The packing of lipids extracted from both aorta and mesenteric arteries of normotensive and hypertensive rats was similar. Lipid extract analysis showed similar phospholipid composition for all membranes. However, cholesterol content was lower in SHR arteries than in normotensive animal arteries. These findings contrast with the fact that the SHR aorta is hyporeactive while the SHR mesenteric artery is hyperreactive to vasopressor agents when compared to the vessels of normotensive animal strains. Hence, factors other than microviscosity of bulk lipids contribute to the vascular smooth muscle reactivity and hypertension of SHR. The excess cholesterol in the arteries of normotensive animal strains apparently is not dissolved in bulk lipids and is not directly related to vascular reactivity since it is present in both the aorta and mesenteric arteries. The lower cholesterol concentrations in SHR arteries may in fact result from metabolic differences due to the hypertensive state or to genes that co-segregate with those that determine hypertension during the process of strain selection.

Solubilization of human erythrocyte membranes by ASB detergents

Understanding the membrane solubilization process and finding effective solubilizing agents are crucial challenges in biochemical research. Here we report results on the interaction of the novel linear alkylamido propyl dimethyl amino propanosulfonate detergents, ASB-14 and ASB-16, with human erythrocyte membranes. An estimation of the critical micelle concentration of these zwitterionic detergents (ASB-14 = 100 µM and ASB-16 = 10 µM) was obtained using electron paramagnetic resonance. The amount of proteins and cholesterol solubilized from erythrocytes by these detergents was then determined. The hemolytic activities of the ASB detergents were assayed and the detergent/lipid molar ratios for the onset of hemolysis (Re sat) and total lysis (Re sol) were calculated, allowing the determination of the membrane binding constants (Kb). ASB-14 presented lower membrane affinity (Kb = 7050 M-1) than ASB-16 (Kb = 15610 M-1). The amount of proteins and cholesterol solubilized by both ASB detergents was higher while Re sat values (0.22 and 0.08 detergent/lipid for ASB-14 and ASB-16, respectively) were smaller than those observed with the classic detergents CHAPS and Triton X-100. These results reveal that, besides their well-known use as membrane protein solubilizers to enhance the resolution of two dimensional electrophoresis/mass spectrometry, ASB-14 and ASB-16 are strong hemolytic agents. We propose that the physicochemical properties of ASB detergents determine their membrane disruption efficiency and can help to explain the improvement in the solubilization of membrane proteins, as reported in the literature.

Preparation of the spin trapping probe, N-tert-butyl-alpha-phenylnitrone, nanoparticle and its affinity to hepatoma cells / 药学学报

This article describes the preparation of the N-tert-butyl-alpha-phenylnitrone (PBN) liposomes and their related characteristics. The PBN liposomes were prepared by film dispersion-supersonic method and the formula of liposomes was optimized by orthogonal uniform design. RP-HPLC was used to qualify the amount of PBN that entered into the hepatoma cells. Necrosis rate was also investigated by fluorescence activated cell sorter (FACS) after PBN liposomes transfection. Result showed that the mean particle size, entrapment efficiency, and polydispersity of the resulting PBN-liposome were 137.5 nm, 71.52% and 0.286, respectively. PBN liposomes can enter into the tumor cell stably and they have higher affinity to hepatoma cell compared with free PBN resulting in a higher necrosis rate after transfection. These results provide a potential method for early diagnosis and treatment of cancer using specific spin trapping probe targeting tumor cells.

Application of ESR imaging technique in studying of skin-penetration properties of nitroxide free radical / 生物医学工程学杂志

A set of L-band electron spin resonance imaging (ESRI) equipment suitable for biological species was developed and an ESRI experiment model for viable skin samples was established. The mechanic process of nitroxide free radical TEMPO (2,2, 6, 6-tetramethyl-1-piperidinyloxy) penetrating through skin sample and the spin density distribution of TEMPO after it interacted with skin sample were detected by the developed ESRI method. Skin samples were extracted from mice back. The experimental samples were prepared by cutting the skin pieces into square shape of 2 x 2 cm2 and then the samples were divided into three groups by treating them with three different methods: Method A, simple treatment by simply cutting the hair; method B, 8% Na2S depilation treatment for 10 min; method C, 8% Na2S depilation and then 5% pancreatic digestion treatment for 2 hours. The liposoluble solvent DMSO (dimethyl sulfoxide) and distilled water were used as two kinds of solvent for the TEMPO liquor. The results indicated that the skin-penetration properties of TEMPO were significantly different among samples treated with different methods and the surface cornifin of skin offered remarkable resistance to TEMPO. The TEMPO liquor of water could hardly penetrate through skins, whereas about 20%-30% of the original TEMPO compounds that solved in liposoluble solvent DMSO could penetrate through the skin sample treated with method C after 16 hours of interaction. Furthermore, the penetration rate of TEMPO through the skin tissue was a strong time dependent process. The preliminary application results suggested that ESRI technique could provide an effective and applicable method for dynamically researching skin-penetration properties of some special kinds of materials such as paramagnetic compounds.

Supercritical CO2 fluid extraction of Rosmarinus officinalis and capability of extracts eliminate OH radical / 中国中药杂志

<p><b>OBJECTIVE</b>Supercritical CO2 fluid extraction process of antioxidation active components from Rosmarinus officinalis was studied.</p><p><b>METHOD</b>A new extraction process of components extracted from R. officinalis by supercritical CO2 fluid extraction (SFE-CO2 ) was studied in detail. The capability of that the extract eliminate *OH radical was tested by electron paramagnetic resonance (EPR) technique and spin catch technique.</p><p><b>RESULT AND CONCLUSION</b>With free radical clearance as index, by range and variance analysis, the optimum extraction process conditions were: keeping pressure at 30 MPa and temperature at 75 degrees C for 1 h, in the same time adding alcohol 0.30 mL x g(-1).</p>