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1.
Reg Anesth Pain Med ; 2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38388010

RESUMO

BACKGROUND: Postdural puncture headache (PDPH) is a relatively common acute complication that occurs following regional anesthesia and is among the clinical features of secondary intracranial hypotension syndrome (IHS).The aim of this study was to document the radiological findings specific to PDPH with brain MRI and to determine whether these findings differed from those described in the third edition of the International Headache Society's International Classification of Headache Disorders (ICHD-3). METHODS: Thirty patients who were diagnosed with PDPH based on the ICHD-3 clinical criteria were enrolled in the study and signed the informed consent form approved by our hospital ethics committee. Their symptoms were recorded and they underwent brain MRI before and after the administration of a gadolinium-based contrast agent within 48-72 hours after the onset of their orthostatic headache. RESULTS: All patients with PDPH presented with MRI features of pachymeningeal enhancement. The thickness of the pachymeningeal enhancement varied from 0.6 mm to 4.1 mm, with a mean of 1.6 mm+0.8.No cases of brain sagging were observed. 4 of the 30 patients presented with intracranial subdural fluid collections, 7 presented with pneumocephalus and 7 pituitary gland enlargement. CONCLUSIONS: The radiological characteristics of IHS and PDPH are most likely the result of compensatory mechanisms in response to decreased cerebrospinal fluid pressure. The acute nature of PDPH probably causes its radiological MRI characteristics to differ from those of IHS, given that no brain sagging could be demonstrated.

2.
Adv Mater ; 36(8): e2304615, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37934471

RESUMO

The spleen is an important mediator of both adaptive and innate immunity. As such, attempts to modulate the immune response provided by the spleen may be conducive to improved outcomes for numerous diseases throughout the body. Here, biomimicry is used to rationally design nanomaterials capable of splenic retention and immunomodulation for the treatment of disease in a distant organ, the postinfarct heart. Engineered senescent erythrocyte-derived nanotheranostic (eSENTs) are generated, demonstrating significant uptake by the immune cells of the spleen including T and B cells, as well as monocytes and macrophages. When loaded with suberoylanilide hydroxamic acid (SAHA), the nanoagents exhibit a potent therapeutic effect, reducing infarct size by 14% at 72 h postmyocardial infarction when given as a single intravenous dose 2 h after injury. These results are supportive of the hypothesis that RBC-derived biomimicry may provide new approaches for the targeted modulation of the pathological processes involved in myocardial infarction, thus further experiments to decisively confirm the mechanisms of action are currently underway. This novel concept may have far-reaching applicability for the treatment of a number of both acute and chronic conditions where the immune responses are either stimulated or suppressed by the splenic (auto)immune milieu.


Assuntos
Biomimética , Infarto do Miocárdio , Humanos , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/patologia , Coração , Imunidade Inata , Imunomodulação
3.
Sensors (Basel) ; 23(15)2023 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-37571531

RESUMO

This paper proposes a sensor system for an internal combustion engine based on a new vision-based algorithm supported by the Schlieren sensorization technique, which allows to acquire the macroscopic parameters of the fuel spray injected in a reciprocating internal combustion engine under unmanned aerial vehicle-like conditions. The sensor system proposed here is able to automatically determine the spray cone angle, its area and its penetration. In addition, the external surface and the volume of the fuel spray is estimated together with the injector opening delay and the ignition delay. The developed algorithm was experimentally tested using a conventional diesel fuel in a single-cylinder engine with an optically adapted head but with easy application and other configurations of reciprocating internal combustion engines. These spray macroscopic parameters allow to analyze, among others, the effect of the spray on the development of both the injection and combustion processes under different operating conditions. The estimation of the external surface of the spray makes it possible to determine the amount of fuel in the spray that is in contact with the surrounding air, with the possibility to link this parameter to the combustion efficiency and emission reduction. Consequently, obtaining the injector opening delay and the ignition delay are important parameters in the combustion phenomenon. In addition, the ignition delay has a great influence on both the engine design and its performance in the study of the air-fuel blending process, in the efficient combustion process and in the reduction of emissions.

4.
Front Microbiol ; 13: 951173, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36051765

RESUMO

Pasteurellaceae family members obtain iron directly from host proteins or through siderophore-dependent mechanisms. Although Gallibacterum anatis expresses different virulence factors, its response to growth under iron restriction is unknown. G. anatis cultured in the presence of 2,2'-dipyridyl, up-expressed an approximately 65 kDa protein and repressed the expression of a 70 kDa protein. MALDI-TOF analysis of those proteins indicated homology with CirA (65 kDa), a protein involved in iron-siderophore acquisition in Mannheimia succinoproducens and a TonB-dependent receptor (70 kDa protein), a protein that binds chicken hemoglobin; however, G. anatis siderophore production was not detected by chromo azurol S (CAS)-BHI agar determination. This putative G. anatis siderophore receptor is under Fur control, but not the hemoglobin binding protein, as observed in G. anatis 12656-12 fur mutant (Ω fur 126.13) grown in the presence or not of 2,2'-dipyridyl. The addition of FeCl3 to the culture medium diminished the growth and biofilm production in approximately 30% and 35%, respectively, in the wild-type strain, but the growth of Ω fur 126.13 strain was not affected and biofilm production increased in 35%. G. anatis Ω fur 126.13 presented lower virulence when it was inoculated to 35-day-old chickens in comparison to the wild-type strain. The induction of more than one iron uptake mechanism could benefit pathogenic microorganisms such as Gallibacterium.

5.
J Clin Med ; 11(9)2022 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-35566448

RESUMO

The effect of different exercises on the position of pelvic organs in women has not been sufficiently assessed. The objective was to analyze the validity and reliability of a new two-dimensional ultrasound algorithm to measure offline the displacement of the bladder base during abdominal exercises. This algorithm could be a useful method to future studies in determine the most appropriate exercises in sports and in rehabilitative program for the pelvic floor in women. All subjects were tested by transverse transabdominal ultrasound. The measurements were conducted offline using a customized code written in MATLAB (Ecolab) for image-processing, and manually on the ultrasound monitor using electronic calipers. The agreement was assessed with a paired t-test, Pearson's linear correlation coefficient (r), the Lin's concordance correlation coefficient (CCC), the intraclass correlation coefficient ICC (A,2) and a Bland-Altman plot. The reliability was confirmed by the interdays intra-rater ICC coefficient. The results were that Ecolab and ultrasound transducer measures did not differ statistically (p = 0.246). Furthermore, both methods showed a very strong relationship, and the Ecolab demonstrated to be a valid and reliable method. We concluded that Ecolab seemed to be a valid and reliable tool to assess the effect of abdominal contractions in the female pelvic floor.

7.
Sensors (Basel) ; 22(3)2022 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-35161700

RESUMO

Swimmers take great advantage by reducing the drag forces either in passive or active conditions. The purpose of this work is to determine the frontal area of swimmers by means of an automated vision system. The proposed algorithm is automated and also allows to determine lateral pose of the swimmer for training purposes. In this way, a step towards the determination of the instantaneous active drag is reached that could be obtained by correlating the effective frontal area of the swimmer to the velocity. This article shows a novel algorithm for estimating the frontal and lateral area in comparison with other models. The computing time allows to obtain a reasonable online representation of the results. The development of an automated method to obtain the frontal surface area during swimming increases the knowledge of the temporal fluctuation of the frontal surface area in swimming. It would allow the best monitoring of a swimmer in their swimming training sessions. Further works will present the complete device, which allows to track the swimmer while acquiring the images and a more realistic model of conventional active drag ones.


Assuntos
Algoritmos , Natação , Fenômenos Biomecânicos , Conhecimento , Projetos Piloto
8.
Int Urogynecol J ; 33(8): 2257-2266, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-33871665

RESUMO

INTRODUCTION AND HYPOTHESIS: The effect of different abdominal contractions on the position of pelvic organs in parous women during postpartum exercises has not been sufficiently assessed. The aim of this study was to evaluate the displacement of the bladder base (BB) during different pelvic floor and abdominal contractions in parous women compared to nulliparous women. We hypothesised that abdominal and perineal contractions will produce a disparate effect on the position of the BB between groups. METHODS: Cross-sectional study including a convenience sample of 63 volunteers (35 nulliparous vs. 28 postpartum women). Transabdominal ultrasound was used in mode B to image the displacement of the BB. The protocol included six different pelvic floor and abdominal contractions commonly used in postpartum rehabilitation. RESULTS: The BB elevated significantly more in the postpartum group compared to nulliparous women when performing submaximal contraction of pelvic floor and transversus abdominis muscles simultaneously with axial elongation of the back (0.93 ± 0.55 cm in parous women vs. 0.66 ± 0.46 cm in nulliparous women). In contrast, the BB was found to descend significantly during a curl-up contraction in both groups (0.93 ± 0.55 cm in parous women vs. 0.66 ± 0.46 cm in nulliparous women). CONCLUSIONS: The overall results of this study showed that perineal and superficial abdominal contractions produced different immediate effects compared to deep abdominal contractions on the displacement of BB in parous and nulliparous women. Further research is required to assess the long-term effects of these contractions.


Assuntos
Diafragma da Pelve , Bexiga Urinária , Estudos Transversais , Feminino , Humanos , Contração Muscular/fisiologia , Diafragma da Pelve/diagnóstico por imagem , Diafragma da Pelve/fisiologia , Ultrassonografia/métodos , Bexiga Urinária/diagnóstico por imagem
9.
J Cardiothorac Vasc Anesth ; 36(2): 553-556, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-33933368

RESUMO

Surgical resection is the treatment of choice both for early-stage lung cancer and pulmonary metastatic disease. For patients with lung tumors who are not eligible for surgery, the minimally invasive modality of radiofrequency ablation (RFA) may be curative and, thus, should be considered. However, opinions regarding the optimal anesthetic technique for pulmonary RFA differ. Here the authors report their experience with the use of ultrasound-guided paravertebral block in minimally-sedated patients undergoing pulmonary RFA. This retrospective study was conducted at a single institution. The 17 consecutive patients underwent 19 pulmonary RFA procedures for primary lung tumor or lung metastases. In all patients, RFA was performed according to the protocol of the hospital. Anesthesia in patients receiving RFA for lung tumors consisted of a thoracic paravertebral block (TPVB), performed between T4 and T8, with minimal sedation. This approach allowed intraoperative communication with the patient and apnea pauses as needed. There were no complications after TPVB, which was well-tolerated by all patients. Only two patients required an alfentanil bolus during RFA because of pleuritic pain. No patient required conversion from sedation to general anesthesia. There were no episodes of hemodynamic instability or desaturation (SaO2 ≤95%), and excessive sedation prevented patient collaboration in only one patient. In conclusion, ultrasound-guided single-injection TPVB is a safe and effective anesthetic technique for high-risk patients undergoing RFA for a primary lung tumor or lung metastases.


Assuntos
Ablação por Cateter , Neoplasias Pulmonares , Bloqueio Nervoso , Ablação por Radiofrequência , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/cirurgia , Estudos Retrospectivos , Resultado do Tratamento , Ultrassonografia de Intervenção
10.
Sensors (Basel) ; 21(11)2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34064277

RESUMO

Cable-driven parallel robots are a special type of robot in which an end-effector is attached to a fixed frame by means of several cables. The position and orientation of the end-effector can be controlled by controlling the length of the cables. These robots present a wide range of advantages, and the control algorithms required have greater complexity than those in traditional serial robots. Measuring the cable tension is an important task in this type of robot as many control algorithms rely on this information. There are several well-known approaches to measure cable tension in cable robots, where a trade-off between complexity and accuracy is observed. This work presents a new device based on strain gauges to measure cable tension specially designed to be applied in cable-driven parallel robots. This device can be easily mounted on the cable near the fixed frame, allowing the cable length and orientation to change freely, while the measure is taken before the cable passes through the guiding pulleys for improved accuracy. The results obtained from the device show a strong repeatability and linearity of the measures.

11.
Artigo em Inglês | MEDLINE | ID: mdl-33809213

RESUMO

In recent years, interest in video game live streaming services has increased as a new communication instrument, social network, source of leisure, and entertainment platform for millions of users. The rise in this type of service has been accompanied by an increase in research on these platforms. As an emerging domain of research focused on this novel phenomenon takes shape, it is necessary to delve into its nature and antecedents. The main objective of this research is to provide a comprehensive reference that allows future analyses to be addressed with greater rigor and theoretical depth. In this work, we developed a meta-review of the literature supported by a bibliometric performance and network analysis (BPNA). We used the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) protocol to obtain a representative sample of 111 published documents since 2012 and indexed in the Web of Science. Additionally, we exposed the main research topics developed to date, which allowed us to detect future research challenges and trends. The findings revealed four specializations or subdomains: studies focused on the transmitter or streamer; the receiver or the audience; the channel or platform; and the transmission process. These four specializations add to the accumulated knowledge through the development of six core themes that emerge: motivations, behaviors, monetization of activities, quality of experience, use of social networks and media, and gender issues.


Assuntos
Jogos de Vídeo , Relações Interpessoais , Motivação
12.
Sensors (Basel) ; 20(24)2020 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-33327553

RESUMO

The propulsive forces and instantaneous power that are generated by a swimmer have a great influence on the swimming performance. This works presents a new device, called SwimOne, for measuring propulsive force and estimating the instantaneous power of the swimmer. In addition, the detailed prototype is able to exert a customizable opposition force to the swimmer for training purpose. The conceptual idea is presented by describing the differential equation of the swimmer and the protocol for a factible estimation of the instantaneous power. The variables that are to be measured and estimated are identified and, consequently, the sensor and actuator systems can be selected. The high-level and detailed designs of the prototype are presented together with the protocol that is carried out in order to validate the sensor and actuation systems. The device is able to monitor the variables of interest of the swimmer together with the propulsive force and instant power. Finally, some experiments are carried out providing the results of several participants swimming in crawl, backstroke, butterfly, and breaststroke styles in the presence of different opposition force. The preliminary results show that SwimOne is valid for measuring instantaneous force and power with different loads in swimming.


Assuntos
Monitorização Fisiológica , Natação , Adulto , Fenômenos Biomecânicos , Humanos , Masculino , Projetos Piloto , Adulto Jovem
13.
Artigo em Inglês | MEDLINE | ID: mdl-32992885

RESUMO

A particularly striking new phenomenon in recent years is the live streaming of video games through popular platforms, such as Twitch. This study focuses on the motivations and types of use underlying viewer participation in live streaming platforms. Based on the uses and gratifications theory, this paper aims to analyse how three basic motivations are related to the use of video game streaming platforms. Furthermore, it examines the moderating effects that significant variables, such as the audience member's age, sex or self-perception of level as a player may exert on this relationship. The results reveal that the three types of motivations are positively associated with use of the platform, although notable differences appear, with informational motivations outweighing entertainment and social motivations. At the same time, no moderating effects on the results of the proposed model were found for the heterogeneity stemming from sex and age. Conversely, the influence of informational motivations on the use of these platforms is moderated by the self-perception of level as a player.


Assuntos
Jogos de Vídeo , Feminino , Humanos , Masculino , Motivação , Autoimagem
14.
Infect Control Hosp Epidemiol ; 41(2): 222-225, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31813403

RESUMO

In this meta-analysis, central venous catheter exposure (pooled odds ratio, 8.02; 95% confidence interval [CI], 2.19-29.31; P < .01) in neonates and length of stay (standardized mean difference, 0.65; 95% CI, 0.26-1.05; P = .01) in an adult population were associated with acquisition of waterborne healthcare-associated infections or colonization in ICUs. The quality of evidence was low.


Assuntos
Infecção Hospitalar/epidemiologia , Unidades de Terapia Intensiva , Microbiologia da Água , Adulto , Cateteres Venosos Centrais/efeitos adversos , Infecção Hospitalar/microbiologia , Humanos , Recém-Nascido , Tempo de Internação , Fatores de Risco , Abastecimento de Água/normas
15.
BMC Med Educ ; 18(1): 209, 2018 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-30208887

RESUMO

BACKGROUND: The Jefferson Scale of Physician Empathy is the most widely used instrument to measure empathy in the doctor-patient relationship. This work pursued cultural adaptation and validation of the original scale, in its health professions version (JSE-HP), for medical students who participate in an Early Clerkship Immersion Programme of a Spanish university. METHODS: The questionnaire was replied by 506 1st, 2nd, 3rd and 5th year medical students from Universidad Francisco de Vitoria, Madrid, in 2014 and 2016. Internal consistency was analysed by means of Cronbach's alpha, and reliability by means of test-retest using the intraclass correlation coefficient and the Bland-Altman method. The construct validity was checked by means of confirmatory factor analysis and association with other empathy-related variables. Criterion validity was compared using Davis' Interpersonal Reactivity Index. RESULTS: Cronbach's alpha was 0.82 (range 0.80-0.85). Item-total score correlations were positive and significant (median 0.45, p <  0.01). The test-retest intraclass correlation coefficient was 0.68 (0.42-0.82). The factor analysis confirmed the three original factors: "perspective taking", "compassionate care" and "standing in the patient's shoes". Women and students who preferred specialities focused on persons obtained the best scores. The JSE-HP scores were positively correlated with Interpersonal Reactivity Index, personality traits were associated with empathy, clinical interview skills and Objective Structured Clinical Examinations. CONCLUSION: The results support the validity and reliability of JSE-HP applied to Spanish medical students.


Assuntos
Empatia , Relações Médico-Paciente , Estudantes de Medicina/psicologia , Inquéritos e Questionários , Estágio Clínico , Competência Clínica , Análise Fatorial , Feminino , Humanos , Masculino , Psicometria , Reprodutibilidade dos Testes , Espanha
16.
Artigo em Inglês | MEDLINE | ID: mdl-28394702

RESUMO

Surface interactions with pollutants and photons are key factors that affect the applications of TiO2 in environmental remediation. In this study, the solubilizing agents dimethylsulfoxide and polyoxyethylene sorbitan monooleate, which act as photon competitors, had no effect on the photocatalytic activity of TiO2-C-Ag film in phenanthrene (PHE) removal. Fiberglass with TiO2-C-Ag coating removed 91.1 ± 5.2 and 99.7 ± 0.4% of PHE in treatments using UVA (365-465 nm) and UVC (254 nm) irradiation, respectively. The use of fiberglass as a support increased the superficial area, thus allowing PHE sorption. C and Ag, which are electrically active impurities in TiO2, enhanced its photocatalytic activity and thus the attraction of the pollutant to its surface. The use of high-frequency UV light (UVC) decreased the amount of carbon species deposited on the TiO2CAg film surface. X-ray photoelectron spectroscopy of the TiO2-C-Ag film revealed extensive oxidation of the carbon deposited on the film under UVC light and loss of electrons from Ag clusters by conversion of Ag0 to Ag3+.


Assuntos
Carbono/química , Vidro/química , Fenantrenos/análise , Prata/química , Titânio/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Carbono/efeitos da radiação , Catálise , Dimetil Sulfóxido/química , Vidro/efeitos da radiação , Oxirredução , Espectroscopia Fotoeletrônica , Fótons , Polissorbatos/química , Prata/efeitos da radiação , Solubilidade , Soluções , Propriedades de Superfície , Titânio/efeitos da radiação , Raios Ultravioleta
17.
Artigo em Inglês | MEDLINE | ID: mdl-21308601

RESUMO

A 2(III)(7-3) fractional factorial experimental design was used to establish 16 culture media, with and without PCBs to enhance the activities of laccase (Lac), manganese peroxidase (MnP), and versatile peroxidase (VP) produced by the white rot fungus Pleurotus ostreatus. The culture was added to 10,000 mg L(-1) of transformer oil, containing 71% of the identified Arochlor 1242. The culture conditions were established with eight variables at two values (levels); pH (4 and 6), agitation (100 and 200 rpm), CuSO(4) (150 and 250 mg L(-1)), MnSO(4) (50 and 200 mg L(-1)), Tween 80 (13 and 3500 mg L(-1)), wheat straw (0 and 2.5 g L(-1)), sugarcane bagasse (0 and 2.5 g L(-1)),and Arochlor 1242 (0 and 7100 mg L(-1)) at 4, 8, 12, 16 and 20 days old culture. Laccase activity was enhanced at a high value of pH and low value of agitation (P<0.001) and correlated positively (R(2)= 0.9; α=0.05) with the removal of polychlorinated biphenyls (PCBs). VP activity was enhanced 27-fold with PCBs, Tween 80 and pH. The MnP activity was increased 1.2-fold with PCBs. The fractional factorial experimental design methodology allowed us to determine the P. ostreatus culture media conditions to enhance Lac and VP activities for efficient removal of Arochlor 1242 (one of the most recalcitrant organochloride pollutants). The factors that shown the greatest effect on Lac activity were: pH, agitation and high concentrations of Arochlor 1242.


Assuntos
Meios de Cultura/química , Poluentes Ambientais/metabolismo , Lacase/metabolismo , Peroxidase/metabolismo , Peroxidases/metabolismo , Pleurotus/enzimologia , Bifenilos Policlorados/metabolismo , Arocloros/metabolismo , Biodegradação Ambiental , Concentração de Íons de Hidrogênio , Modelos Lineares , Modelos Químicos , Fatores de Tempo
18.
Infect Control Hosp Epidemiol ; 26(12): 903-9, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16417029

RESUMO

OBJECTIVE: To investigate the effect of preoperative initiation of low molecular weight heparin as prophylaxis for deep venous thrombosis in patients at risk of developing surgical-site infections after knee arthroplasty. DESIGN: Case-control study nested in a cohort. The incidence of surgical-site infection in the cohort was calculated. With the use of data extracted from medical histories and after adjustment for other risk factors, the effect of preoperative heparinization on the risk of incisional and prosthetic infection among case-patients and control-patients (1:3 ratio) was assessed. SETTING: Orthopedic department in a tertiary-care referral hospital. PATIENTS: A cohort of 160 consecutive patients who had received prosthetic knee implants between October 1, 2001, and November 30, 2003. RESULTS: Eighteen patients with surgical-site infections were identified, yielding an incidence of incisional and prosthetic infection of 6.9 (95% confidence interval [CI95], 3.5 to 12.0) and 4.4 (CI95, 1.8 to 8.8) cases per 100 patients undergoing surgery, respectively. Surgical-site infection was associated with preoperative use of low molecular weight heparin (odds ratio [OR], 6.2 after adjustment for medical and surgical factors; CI95 1.5 to 23). Prosthetic infection was strongly associated with preoperative use of prophylaxis (OR, undetermined [100% exposure in case-patients vs 35% exposure in control-patients]; P = .002), but incisional surgical-site infection was not. CONCLUSION: The use of low molecular weight heparins immediately before knee arthroplasty as prophylaxis for deep venous thrombosis should be questioned because of probable increased risk of prosthetic infection.


Assuntos
Anticoagulantes/efeitos adversos , Artroplastia do Joelho/efeitos adversos , Heparina de Baixo Peso Molecular/efeitos adversos , Infecções Relacionadas à Prótese/etiologia , Trombose Venosa/prevenção & controle , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticoagulantes/uso terapêutico , Estudos de Casos e Controles , Quimioprevenção , Estudos de Coortes , Feminino , Heparina de Baixo Peso Molecular/uso terapêutico , Humanos , Prótese do Joelho/efeitos adversos , Masculino , Pessoa de Meia-Idade , Cuidados Pré-Operatórios , Infecção da Ferida Cirúrgica/etiologia
19.
J Agric Food Chem ; 52(4): 972-9, 2004 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-14969559

RESUMO

HPLC-UV, (1)H NMR, (13)C NMR, and (1)H-(1)H COSY analyses revealed that exogenous capsaicin was specifically converted into 5,5'-dicapsaicin by both cell suspension cultures of Capsicum annuum var. annuum (chili Jalapeño chigol) and their soluble and NaCl-extracted cell wall protein fractions under oxidative conditions. In cell suspension cultures 5,5'-dicapsaicin was found only in biomass of capsaicin-fed cultures. This compound has not been detected before either in fresh fruits or in in vitro cultures of Capsicum. The transformation of capsaicin by different protein fractions revealed that most of the enzymatic activity was located in the NaCl-extracted, or ionic cell wall bound, protein, and that it was strictly dependent on H(2)O(2). These results might in part explain some previously described features of capsaicin production by in vitro cultures of Capsicum. The implications of the results regarding the catabolism of capsaicinoids are discussed.


Assuntos
Capsaicina/metabolismo , Capsicum/metabolismo , Parede Celular/química , Proteínas de Plantas/metabolismo , Capsaicina/análogos & derivados , Células Cultivadas , Espectroscopia de Ressonância Magnética , Extratos Vegetais/química , Cloreto de Sódio
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