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1.
Foods ; 12(3)2023 Feb 01.
Article in English | MEDLINE | ID: mdl-36766140

ABSTRACT

Marine algae have been emerging as natural sources of bioactive compounds, such as soluble dietary fibers and peptides, presenting special interest as ingredients for functional foods. This study developed a cheese spread incorporating red seaweed Osmundea pinnatifida extract and subsequently characterized it in terms of nutritional, pH, and microbiological parameters and bioactivities including prebiotic, antidiabetic, antihypertensive, and antioxidant activities. This food was produced through incorporation of O. pinnatifida extract (3%), obtained via enzymatic extraction Viscozyme L in a matrix containing whey cheese (75%) and Greek-type yoghurt (22%). The product was then subjected to thermal processing and subsequently stored for 21 days at 4 °C. During storage, this food showed a high pH stability (variations lower than 0.2 units), the absence of microbial contamination and all tested bioactivities at the sampling timepoints 0 and 21 days. Indeed, it exerted prebiotic effects under Lactobacillus acidophilus LA-5® and Bifidobacterium animalis subsp. lactis BB-12®, increasing their viability to around 4 and 0.5 log CFU/g, respectively. In addition, it displayed antidiabetic (α-glucosidase inhibition: 5-9%), antihypertensive (ACE inhibition: 50-57%), and antioxidant (ABTS: 13-15%; DPPH: 3-5%; hydroxyl radical: 60-76%) activities. In summary, the cheese spread produced may be considered an innovative food with high potential to contribute toward healthier status and well-being of populations.

2.
Pharmaceutics ; 14(12)2022 Dec 07.
Article in English | MEDLINE | ID: mdl-36559229

ABSTRACT

Faecalibacterium duncaniae is an intestinal commensal bacterium proposed as a next-generation probiotic due to its promising outcomes in the treatment and prevention of several human diseases, which demonstrate its multiple contributions to the host's health. However, its strict anaerobic nature has created several hurdles in the development of functional foods, nutraceuticals, and biotherapeutic products. Herein, we explored freeze-dried formulations containing prebiotics, cryoprotectants, and antioxidant agents as a technological strategy to enhance the viability of F. duncaniae DSM 17677 upon aerobic storage and gastrointestinal tract conditions. Our results indicate that freeze-dried F. duncaniae in a matrix containing inulin, sucrose, cysteine, and riboflavin survived at levels higher than 106 CFU/g and around 105 CFU/g after 1 and 4 days of aerobic storage at room temperature, respectively. Thus, the freeze-dried formulation with inulin, sucrose, cysteine, and riboflavin presents as a protective strategy to improve F. duncaniae viability under aerobic environments. Nevertheless, incorporation of a suitable coating aimed at protecting F. duncaniae against the detrimental gastrointestinal passage effects is urgently required, given its high susceptibility to extreme acidic pH values and bile.

3.
Article in English | MEDLINE | ID: mdl-35954507

ABSTRACT

Akkermansia muciniphila is a Gram-negative intestinal anaerobic bacterium recently proposed as a novel probiotic candidate to be incorporated in food and pharmaceutical forms. Despite its multiple health benefits, the data addressing its antimicrobial susceptibility profile remain scarce. However, the absence of acquired resistance in probiotic strains is a compulsory criterion for its approval in the qualified presumption of safety list. This study aimed at characterizing the A. muciniphila DSM 22959 strain's antimicrobial susceptibility profile using phenotypic and in silico approaches. To establish the phenotypic antimicrobial susceptibility profile of this strain, minimum inhibitory concentrations of eight antimicrobials were determined using broth microdilution and E-test methods. Additionally, the A. muciniphila DSM 22959 genome was screened using available databases and bioinformatics tools to identify putative antimicrobial resistance genes (ARG), virulence factors (VF), genomic islands (GI), and mobile genetic elements (MGE). The same categorization was obtained for both phenotypic methods. Resistance phenotype was observed for gentamicin, kanamycin, streptomycin, and ciprofloxacin, which was supported by the genomic context. No evidence was found of horizontal acquisition or potential transferability of the identified ARG and VF. Thus, this study provides new insights regarding the phenotypic and genotypic antimicrobial susceptibility profiles of the probiotic candidate A. muciniphila DSM 22959.


Subject(s)
Anti-Infective Agents , Probiotics , Akkermansia , Anti-Bacterial Agents/pharmacology , Anti-Infective Agents/pharmacology , Base Composition , Drug Resistance, Bacterial/genetics , Phylogeny , RNA, Ribosomal, 16S , Sequence Analysis, DNA , Verrucomicrobia/genetics , Virulence Factors
4.
Pharmaceuticals (Basel) ; 15(5)2022 May 20.
Article in English | MEDLINE | ID: mdl-35631454

ABSTRACT

Akkermansia muciniphila is regarded as a promising next-generation probiotic or live biotherapeutic candidate. Effective delivery strategies must be developed to ensure high enough viability of the probiotic strain throughout its industrial formulation, distribution chain, shelf-life, and, ultimately, the host's gastrointestinal tract, where it should exert its beneficial effect(s). Among the possible methodologies, spray-drying is considered industrially attractive regarding its costs, efficiency, and scalability, with the due parameter customization. In this study, spray-drying was explored as a one-step process to encapsulate A. muciniphila DSM 22959, testing the drying settings and three different dairy-based matrices. Microcapsule morphology and size was assessed, and viability throughout storage at 4 or 22 °C and simulated gastrointestinal passage was determined. Akkermansia muciniphila microencapsulation by spray-drying, using 10% skim milk and inlet/outlet temperatures of 150/65 °C, is effective in terms of viability stabilization, both during prolonged aerobic storage and exposure to simulated gastrointestinal passage. Akkermansia muciniphila viability was maintained at around 107 CFU/g up to 28 days at 4 °C under aerobic conditions with viability losses inferior to 1 log reduction. This methodology provides the necessary conditions to efficiently deliver the recommended dose of live A. muciniphila in the human gut as a live biotherapeutic product.

5.
Crit Rev Food Sci Nutr ; 62(30): 8249-8264, 2022.
Article in English | MEDLINE | ID: mdl-34024191

ABSTRACT

Candidiasis (e.g., oral, gastrointestinal, vaginal, urinary tract, systemic) is a worldwide growing problem, since antifungal resistance and immunosuppression states are rising. To address this problem, very few drugs are available for the treatment of Candida spp. infections. Therefore, novel therapeutic strategies are urgently required. Probiotics have been proposed for the prevention and treatment of bacterial infections due to their safety record and efficacy, however, little is still known about their potential role regarding fungal infections. The purpose of this review is to present an updated summary of the evidence of the antifungal effects of probiotics along with a discussion of their potential use as an alternative/complementary therapy against Candida spp. infections. Thus, we performed a literature search using appropriate keywords ("Probiotic + Candida", "Candidiasis treatment", and "Probiotic + candidiasis") to retrieve relevant studies (both preclinical and clinical) with special emphasis on the works published in the last 5 years. An increasing amount of evidence has shown the potential usefulness of probiotics in the management of oral and vulvovaginal candidiasis in recent years. Among other results, we found that, as for bacterial infections, Lactobacillus, Bifidobacterium, and Saccharomyces are the most studied and effective genus for this purpose. However, in other areas, particularly in skincandidiaisis, studies are low or lacking. Thus, further investigation is necessary including in vitro and in vivo studies to establish the usefulness of probiotics in the management of candidiasis.


Subject(s)
Candidiasis , Probiotics , Female , Humans , Antifungal Agents/pharmacology , Antifungal Agents/therapeutic use , Candidiasis/drug therapy , Candidiasis/prevention & control , Probiotics/therapeutic use , Candida , Lactobacillus
6.
Int J Food Microbiol ; 363: 109501, 2022 Feb 16.
Article in English | MEDLINE | ID: mdl-34953344

ABSTRACT

Faecalibacterium prausnitzii, a resident anaerobic bacterium commonly found in healthy gut microbiota, has been proposed as a next generation probiotic with high potential for application in food matrices and pharmaceutical formulations. Despite its recognized health benefits, detailed information regarding its antimicrobial susceptibility profile is still lacking. However, this information is crucial to determine its safety, since the absence of acquired antimicrobial resistance is required to qualify a probiotic candidate as safe for human and animal consumption. Herein, the antimicrobial susceptibility profile of F. prausnitzii DSM 17677 strain was evaluated by integrating both phenotypic and in silico data. Phenotypic antimicrobial susceptibility was evaluated by determining minimum inhibitory concentrations of 9 antimicrobials using broth microdilution and E-test® methods. Also, the whole genome of F. prausnitzii DSM 17677 was analysed, using several databases and bioinformatics tools, to identify possible antibiotic resistance genes (ARG), genomic islands (GI) and mobile genetic elements (MGE). With exception of erythromycin, the same classification (susceptible or resistant) was obtained in both broth microdilution and E-test® methods. Phenotypic resistance to ampicillin, gentamycin, kanamycin and streptomycin were detected, which was supported by the genomic context. Other ARG were also identified but they seem not to be expressed under the tested conditions. F. prausnitzii DSM 17677 genome contains 24 annotated genes putatively involved in resistance against the following classes of antimicrobials: aminoglycosides (such as gentamycin, kanamycin and streptomycin), macrolides (such as erythromycin), tetracyclines and lincosamides. The presence of putative ARG conferring resistance to ß-lactams could only be detected using a broader homology search. The majority of these genes are not encoded within GI or MGE and no plasmids were reported for this strain. Despite the fact that most genes are related with general resistance mechanisms, a streptomycin-specific ARG poses the only potential concern identified. This specific ARG is encoded within a GI and a MGE, meaning that it could have been laterally acquired and might be transferred to other bacteria present in the same environment. Thus, our findings provide relevant insights regarding the phenotypic and genotypic antimicrobial resistance profiles of the probiotic candidate F. prausnitzii DSM 17677.


Subject(s)
Faecalibacterium prausnitzii , Probiotics , Animals , Anti-Bacterial Agents/pharmacology , Base Composition , Drug Resistance, Bacterial/genetics , Humans , Phylogeny , RNA, Ribosomal, 16S , Sequence Analysis, DNA
7.
Article in English | MEDLINE | ID: mdl-32582673

ABSTRACT

In the last years several human commensals have emerged from the gut microbiota studies as potential probiotics or therapeutic agents. Strains of human gut inhabitants such as Akkermansia, Bacteroides, or Faecalibacterium have shown several interesting bioactivities and are thus currently being considered as food supplements or as live biotherapeutics, as is already the case with other human commensals such as bifidobacteria. The large-scale use of these bacteria will pose many challenges and drawbacks mainly because they are quite sensitive to oxygen and/or very difficult to cultivate. This review highlights the properties of some of the most promising human commensals bacteria and summarizes the most up-to-date knowledge on their potential health effects. A comprehensive outlook on the potential strategies currently employed and/or available to produce, stabilize, and deliver these microorganisms is also presented.

8.
Crit Rev Food Sci Nutr ; 60(11): 1783-1796, 2020.
Article in English | MEDLINE | ID: mdl-31062600

ABSTRACT

In recent years, scientific community has been gathering increasingly more insight on the dynamics that are at play in metabolic and inflammatory disorders. These rapidly growing conditions are reaching epidemic proportions, bringing clinicians and researcher's new challenges. The specific roles and modulating properties that beneficial/probiotic bacteria hold in the context of the gut ecosystem seem to be key to avert these inflammatory and diet-related disorders. Faecalibacterium prausnitzii, Akkermansia muciniphila and Eubacterium hallii have been identified as candidates for next generation probiotics (NGPs) with exciting potential for the prevention and treatment of such of dysbiosis-associated diseases. The challenges of these non-conventional native gut bacteria lie mainly on their extreme sensitivity to O2 traces. If these strains are to be used successfully in food, supplements or drugs they need to be stable and active in humans. In the present review, we present an overall perspective of the most updated scientific literature on the newly called NGPs through the 5W1H (What, Why, Who, Where, When, and How) method, an innovative and attractive problem-solving approach that provides the reader an effective understanding of the issue at hand.


Subject(s)
Gastrointestinal Microbiome , Probiotics , Clostridiales , Dysbiosis/prevention & control , Faecalibacterium prausnitzii , Humans , Verrucomicrobia
9.
Anaerobe ; 61: 102135, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31875576

ABSTRACT

Data regarding Akkermansia muciniphila viability under stress remains scarce despite its beneficial potential. Therefore, the main goal was to assess A. muciniphila culturability when exposed to different temperatures, atmospheres and gastrointestinal simulated conditions. Cultivable cell numbers A. muciniphila remain high after refrigerated and room temperatures oxygen exposure, and gastrointestinal passage.


Subject(s)
Environment , Gastrointestinal Tract , Stress, Physiological , Temperature , Verrucomicrobia/physiology , Adaptation, Biological , Akkermansia , Gastrointestinal Tract/microbiology , Microbial Viability
10.
Expert Opin Drug Deliv ; 14(6): 769-782, 2017 06.
Article in English | MEDLINE | ID: mdl-27492462

ABSTRACT

INTRODUCTION: Alginate-based particles have emerged as one of the most extensively searched drug delivery platforms due to their inherent properties, including good biocompatibility and biodegradability. Moreover, the low price, easy availability, natural origin, versatility and sol-gel transition properties, make alginate an ideal candidate to produce particles with different applications. Several techniques have been developed and optimized to prepare microparticles and nanoparticles in order to achieve more rational, coherent, efficient and cost-effective procedures. Alginate represents a suitable choice concerning delivery systems' safety, and therefore alginate-based particles have shown to be useful in the field of drug delivery with a special focus on biological encapsulants. Area covered: This review will provide an overview of alginate-based delivery systems, covering the innovative preparation methods of the last decade, the advantages and disadvantages of the most used methods, their wide diversity of applications and safety concerns. Expert opinion: The progression of nanotechnology over the last decades has stimulated the refinement of former microencapsulation methods and the exploration of new approaches towards the submicron scale with increased attention being focused on the safety of nanoparticles and product performance. Therefore, the design and optimization of the preparation methods of alginate-based microparticles and nanoparticles as well as their nontoxicity, biocompatibility and biodegradability to reach the desired application have been widely explored.


Subject(s)
Alginates/chemistry , Drug Delivery Systems , Nanoparticles , Glucuronic Acid/chemistry , Hexuronic Acids/chemistry , Humans , Nanotechnology
11.
Clin Implant Dent Relat Res ; 18(1): 40-50, 2016 Feb.
Article in English | MEDLINE | ID: mdl-24909241

ABSTRACT

PURPOSE: The aim of this prospective clinical study was to evaluate the clinical and histomorphometric data of newly formed bone tissue from fresh frozen human allograft in sinus lift surgery. PATIENTS AND METHODS: Thirty-three sinus lift procedures were performed in 20 patients, divided into two groups. The control group (n = 8) received autogenous bone from the mandibular ramus, and the experimental group (n = 12) received fresh frozen bone (FFB) allograft in chips. After 6 months, 52 implants were placed and 50 biopsies were collected for histomorphometric analysis. Cone beam computed tomography scans were performed at preoperative, immediate postoperative, and delayed postoperative time intervals to assess the degree of graft volume loss. RESULTS: There was no statistically significant difference between groups as regards degree of graft volume loss (p = .983), total bone area (p = .191), remaining particles (p = .348), and proportion of active osteoblasts (p = .867). There was a statistically significant difference in the vitality rate between the groups (p = .043). In both groups, all implants were clinically osseointegrated after 4 months. CONCLUSION: FFB allograft was shown to be a feasible substitute for autogenous bone graft in sinus lift surgery.


Subject(s)
Bone Transplantation/methods , Sinus Floor Augmentation/methods , Adult , Aged , Allografts , Biopsy , Brazil , Cone-Beam Computed Tomography , Female , Humans , Male , Mandible/transplantation , Middle Aged , Prospective Studies , Treatment Outcome
12.
Methods Mol Biol ; 899: 471-87, 2012.
Article in English | MEDLINE | ID: mdl-22735970

ABSTRACT

Therapeutic proteins represent a significant part of the new pharmaceuticals coming on the market every year and are now widely spread in therapy to treat or relief symptoms related to many metabolic and oncologic diseases. The parenteral route remains as a primary strategy for protein administration essentially due to its specific physicochemical properties. However, the research on alternative nonparenteral delivery routes continues. The high molecular weight (MW), hydrophilicity, and charged nature of therapeutically valued proteins render transport through membranes very difficult. In this regard, chitosan arises as a promising candidate for the development of protein-containing drug formulations, due to its exceptional biological properties. Chitosan-based delivery systems have been proposed as valid approaches to provide protective conditions to proteins from denaturation and loss of activity, during preparation and delivery, as well as during long-term storage of the prepared formulation. In this chapter, one production method of a chitosan-based nanoparticle formulation is presented, as well as several characterization techniques to assess both nanoparticles and proteins characteristics and stability.


Subject(s)
Chitosan/chemistry , Drug Carriers/chemistry , Insulin , Nanoparticles/chemistry , Proteins , Chemistry, Pharmaceutical , Drug Delivery Systems , Humans , Insulin/chemistry , Insulin/therapeutic use , Particle Size , Proteins/chemistry , Proteins/therapeutic use
13.
Biomatter ; 2(4): 329-39, 2012.
Article in English | MEDLINE | ID: mdl-23507897

ABSTRACT

PLGA nanoparticles are useful to protect and deliver proteins in a localized or targeted manner, with a long-term systemic delivery pattern intended to last for a period of time, depending on polymer bioerosion and biodegradability. However, the principal concern regarding these carriers is the hydrolytic instability of polymer in aqueous suspension. Freeze-drying is a commonly used method to stabilize nanoparticles, and cryoprotectants may be also used, to even increase its physical stability. The aim of the present work was to analyze the influence of cryoprotectants on nanoparticle stability and porosity after freeze-drying, which may influence protein release and stability. It was verified that freeze-drying significantly increased the number of pores on PLGA-NP surface, being more evident when cryoprotectants are added. The presence of pores is important in a lyophilizate to facilitate its reconstitution in water, although this may have consequences to protein release and stability. The release profile of insulin encapsulated into PLGA-NP showed an initial burst in the first 2 h and a sustained release up to 48 h. After nanoparticles freeze-drying the insulin release increased about 18% in the first 2 h due to the formation of pores, maintaining a sustained release during time. After freeze-drying with cryoprotectants, the amount of insulin released was higher for trehalose and lower for sucrose, glucose, fructose and sorbitol comparatively to freeze-dried PLGA-NP with no cryoprotectant added. Besides the porosity, the ability of cryoprotectants to be adsorbed on the nanoparticles surface may also play an important role on insulin release and stability.


Subject(s)
Cryoprotective Agents/chemistry , Drug Delivery Systems , Insulin/administration & dosage , Lactic Acid/chemistry , Nanoparticles/chemistry , Polyglycolic Acid/chemistry , Freeze Drying , Humans , Insulin/chemistry , Microscopy, Electron, Scanning , Microscopy, Electron, Transmission , Nanomedicine , Polylactic Acid-Polyglycolic Acid Copolymer , Porosity , Recombinant Proteins/administration & dosage , Surface Properties , Surface-Active Agents/chemistry , Time Factors
14.
Lasers Med Sci ; 27(4): 703-11, 2012 Jul.
Article in English | MEDLINE | ID: mdl-21732113

ABSTRACT

Little is known about the benefits of low-level laser therapy (LLLT) on improvement of stability of dental implants. The aim of this randomized clinical study was to assess the LLLT effect on implants stability by means of resonance frequency analysis (RFA). Thirty implants were distributed bilaterally in the posterior mandible of eight patients. At the experimental side, the implants were submitted to LLLT (830 nm, 86 mW, 92.1 J/cm(2), 0.25 J, 3 s/point, at 20 points), and on the control side, the irradiation was simulated (placebo). The first irradiation was performed in the immediate postoperative period, and it was repeated every 48 h in the first 14 days. The initial implant stability quotient (ISQ) of the implants was measured by means of RFA. New ISQ measurements were made after 10 days, 3, 6, 9, and 12 weeks. The initial ISQ values ranged from 65-84, with a mean of 76, undergoing a significant drop in stability from the 10th day to the 6th week in the irradiated group, and presenting a gradual increase from the 6th to the 12th week. The highest ISQ values were observed on the 10th day in the irradiated group, and the lowest in the 6th week in both groups. Under the conditions of this study, no evidence was found of any effect of LLLT on the stability of the implants when measured by RFA. Since high primary stability and good bone quality are of major relevancy for a rigid bone-implant interface, additional LLLT may have little impact macroscopically.


Subject(s)
Dental Implantation, Endosseous/methods , Dental Implants , Low-Level Light Therapy/methods , Mandible/surgery , Adult , Dental Stress Analysis , Denture Retention , Double-Blind Method , Female , Follow-Up Studies , Humans , Intention to Treat Analysis , Male , Materials Testing , Middle Aged , Osseointegration , Young Adult
15.
Arq. bras. cardiol ; 87(5): e189-e191, nov. 2006. ilus
Article in Portuguese, English | LILACS | ID: lil-452163

ABSTRACT

A primeira descrição de dor severa no trajeto do nervo glossofaríngeo foi realizada por Weisenberg, em 1910¹, em um paciente com tumor do ângulo ponto cerebelar. Entretanto, coube a Harris, em 1926², nomear como nevralgia do nervo glossofaríngeo esse raro quadro clínico, caracterizado por paroxismos de dor intensa, unilaterais, na região posterior da língua, no palato mole, na garganta e na região lateral e posterior da faringe, irradiando para o ouvido. A dor pode ser desencadeada por deglutição, tosse, bocejo ou mastigação e normalmente dura de segundos a minutos. A associação de nevralgia do glossofaríngeo e síncope é muito rara e se deve a breves períodos de bradicardia, assistolia ou hipotensão, sendo a primeira descrição dessa associação, com essa fisiopatologia, realizada por Riley e cols., em 1942.


The first description of severe pain in the distribution of the glossopharyngeal nerve is credited to Weisenberg, in 1910¹, in a patient with cerebellopontine angle tumor. However, it was Harris, in 1926², who coined the term glossopharyngeal neuralgia to describe this rare condition characterized by paroxysms of excruciating pain located laterally at the back of the tongue, soft palate, throat, and lateral and posterior pharynx, radiating to the ear. Swallowing, coughing, yawning or chewing may trigger pain, which usually lasts from seconds to minutes. The association between glossopharyngeal neuralgia and syncope is very rare, being identified by brief episodes of bradycardia, asystole, and hypotension. Such an association, with this same pathophysiology, was first described by Riley et al in 1942.


Subject(s)
Humans , Male , Aged , Glossopharyngeal Nerve Diseases/complications , Neuralgia/complications , Syncope/etiology , Follow-Up Studies , Pacemaker, Artificial , Syncope/diagnosis , Syncope/surgery , Treatment Outcome
16.
REBLAMPA Rev. bras. latinoam. marcapasso arritmia ; 19(2): 83-88, abr.-jun. 2006. ilus
Article in Portuguese | LILACS | ID: lil-438635

ABSTRACT

O trabalho reporta e explica um episódio intrigante da estimulação artifical verificado durante o implante de um sistema de marcapasso, com o gerador programado para polaridade de estimulação unipolar, o marcapasso fora da loja e a carcaça isolada do corpo do paciente. O comportamento do gerador de pulso é analisado, considerando a prática médica e a evolução tecnológica e conceitual.


Subject(s)
Humans , Male , Pacemaker, Artificial/adverse effects , Pacemaker, Artificial/history
17.
Arq Bras Cardiol ; 87(5): e189-91, 2006 Nov.
Article in English, Portuguese | MEDLINE | ID: mdl-17396191

ABSTRACT

The first description of severe pain in the distribution of the glossopharyngeal nerve is credited to Weisenberg, in 1910, in a patient with cerebellopontine angle tumor. However, it was Harris, in 1926, who coined the term glossopharyngeal neuralgia to describe this rare condition characterized by paroxysms of excruciating pain located laterally at the back of the tongue, soft palate, throat, and lateral and posterior pharynx, radiating to the ear. Swallowing, coughing, yawning or chewing may trigger pain, which usually lasts from seconds to minutes. The association between glossopharyngeal neuralgia and syncope is very rare, being identified by brief episodes of bradycardia, asystole, and hypotension. Such an association, with this same pathophysiology, was first described by Riley et al in 1942.


Subject(s)
Glossopharyngeal Nerve Diseases/complications , Neuralgia/complications , Syncope/etiology , Aged , Humans , Male , Pacemaker, Artificial , Syncope/therapy , Treatment Outcome
18.
Metab Eng ; 7(5-6): 329-36, 2005.
Article in English | MEDLINE | ID: mdl-16095939

ABSTRACT

Clostridium butyricum is to our knowledge the best natural 1,3-propanediol producer from glycerol and the only microorganism identified so far to use a coenzyme B12-independent glycerol dehydratase. However, to develop an economical process of 1,3-propanediol production, it would be necessary to improve the strain by a metabolic engineering approach. Unfortunately, no genetic tools are currently available for C. butyricum and all our efforts to develop them have been so far unsuccessful. To obtain a better "vitamin B12-free" biological process, we developed a metabolic engineering strategy with Clostridium acetobutylicum. The 1,3-propanediol pathway from C. butyricum was introduced on a plasmid in several mutants of C. acetobutylicum altered in product formation. The DG1(pSPD5) recombinant strain was the most efficient strain and was further characterized from a physiological and biotechnological point of view. Chemostat cultures of this strain grown on glucose alone produced only acids (acetate, butyrate and lactate) and a high level of hydrogen. In contrast, when glycerol was metabolized in chemostat culture, 1,3-propanediol became the major product, the specific rate of acid formation decreased and a very low level of hydrogen was observed. In a fed-batch culture, the DG1(pSPD5) strain was able to produce 1,3-propanediol at a higher concentration (1104 mM) and productivity than the natural producer C. butyricum VPI 3266. Furthermore, this strain was also successfully used for very long term continuous production of 1,3-propanediol at high volumetric productivity (3 g L-1 h-1) and titer (788 mM).


Subject(s)
Clostridium acetobutylicum/genetics , Clostridium acetobutylicum/metabolism , Escherichia coli/genetics , Genetic Enhancement/methods , Glycerol/metabolism , Industrial Microbiology/methods , Propylene Glycols/metabolism , Cell Culture Techniques/methods , Escherichia coli/metabolism
19.
Rev. Soc. Cardiol. Estado de Säo Paulo ; 14(2): 213-224, mar.-abr. 2004. ilus, tab
Article in Portuguese | LILACS | ID: lil-406399

ABSTRACT

As indicações da estimulação cardíaca temporária são apresentadas em várias situações de infarto agudo, pós operatório de cirurgia cardíaca, pré operatório em geral, intoxicações medicamentosas e processos inflamatórios, entre outras.A técnica de estimulação é classificada em cinco tipos: cutânea-torácica, esofágica, miocárdica percutânea, epicárdica, descrevendo-se os procedimentos e os detalhes tático-técnicos.A utilização do marcapasso externo com a determinação dos limiares de estimulação e sensibilidade, a programação a ser establecida do gerador e os cuidados e condutas a serem tomados durante sua utilização são explicados.A vantagem da estimulação com sincronismo atrioventricular, apresentando-se o cabo elétrodo temporário quadripolar desenvolvido para estimulação VDD ou DDD, é ressaltada


Subject(s)
Cardiac Pacing, Artificial/methods , Cardiac Pacing, Artificial/trends , Cardiac Pacing, Artificial , Pacemaker, Artificial/trends , Pacemaker, Artificial , Myocardial Infarction/classification , Myocardial Infarction/rehabilitation
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