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1.
Artículo en Inglés | MEDLINE | ID: mdl-35680482

RESUMEN

Condylar hyperplasia is one of the causes of facial asymmetry and malocclusion, characterized by enlargement of the lower jaw due to excessive condyle growth activity. The aim of this study was to use micro-computed tomography (micro-CT) to evaluate the bone architecture of the condylar head and determine whether there are differences between patients with various forms of unilateral condylar hyperplasia (UCH): hemimandibular hyperplasia, elongation, and mixed form. The cohort consisted of 28 patients with a mean age of 21.9 years. All patients underwent surgical treatment (condylar shaving) for active pathological growth activity. The portion of the condylar head removed was imaged by micro-CT and subsequently evaluated. Micro-CT imaging and semiquantitative and quantitative evaluation of the bone structure (percentage bone volume, surface density, trabecular thickness, trabecular separation, degree of anisotropy, and porosity of the subchondral bone) did not reveal significant differences between the individual types of condylar hyperplasia (P > 0.05). There were no significant differences in bone structure between the anterior and posterior portions of the condylar head. No statistically significant differences between individual groups of UCH were found in the micro-CT evaluation of the condylar head bone architecture.

2.
Bratisl Lek Listy ; 122(1): 24-27, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33393316

RESUMEN

OBJECTIVE: Cerebral microdialysis (CMD) is a method used to measure the concentration of metabolites and glycerol in the interstitium of the brain. The aim of this study was to investigate the effect of parenterally applied medication and nutrition containing external free glycerol (EFG) on cerebral values of glycerol in patients monitored and treated for non-traumatic subarachnoid hemorrhage (SAH). METHODS: In 13 patients, the values of CG concentrations were measured using CMD. The amounts of parenterally applied EFG (in hourly intervals) were calculated from patient records. All data were gathered retrospectively. To analyze the association between the parameters of interest and their relationship, Spearman´s correlation and p-values were calculated. RESULTS: There was no evident relationship between the CG and EFG concentrations when the dataset was analyzed as a whole (r = -0.146). However, when the analysis was applied to single patients, a varying degree of correlations was discovered in 7 patients (r = 0.431-0.867). CONCLUSION: The possible effect of externally administered glycerol contained in pharmaceuticals and nutrition on its brain concentrations must be considered when interpreting data of CMD (Tab. 2, Fig. 4,Ref. 16) Keywords: glycerol, microdialysis, brain, subarachnoid hemorrhage.


Asunto(s)
Encéfalo , Glicerol , Humanos , Microdiálisis , Estudios Retrospectivos , Hemorragia Subaracnoidea
3.
Nat Commun ; 11(1): 4037, 2020 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-32788704

RESUMEN

Excitons with binding energies of a few hundreds of meV control the optical properties of transition metal dichalcogenide monolayers. Knowledge of the fine structure of these excitons is therefore essential to understand the optoelectronic properties of these 2D materials. Here we measure the exciton fine structure of MoS2 and MoSe2 monolayers encapsulated in boron nitride by magneto-photoluminescence spectroscopy in magnetic fields up to 30 T. The experiments performed in transverse magnetic field reveal a brightening of the spin-forbidden dark excitons in MoS2 monolayer: we find that the dark excitons appear at 14 meV below the bright ones. Measurements performed in tilted magnetic field provide a conceivable description of the neutral exciton fine structure. The experimental results are in agreement with a model taking into account the effect of the exchange interaction on both the bright and dark exciton states as well as the interaction with the magnetic field.

4.
Nanoscale ; 12(35): 18153-18159, 2020 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-32853305

RESUMEN

Low temperature and polarization resolved magneto-photoluminescence experiments are used to investigate the properties of dark excitons and dark trions in a monolayer of WS2 encapsulated in hexagonal BN (hBN). We find that this system is an n-type doped semiconductor and that dark trions dominate the emission spectrum. In line with previous studies on WSe2, we identify the Coulomb exchange interaction coupled neutral dark and grey excitons through their polarization properties, while an analogous effect is not observed for dark trions. Applying the magnetic field in both perpendicular and parallel configurations with respect to the monolayer plane, we determine the g-factor of dark trions to be g ∼ -8.6. Their decay rate is close to 0.5 ns, more than 2 orders of magnitude longer than that of bright excitons.

5.
Sci Rep ; 10(1): 4981, 2020 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-32188877

RESUMEN

Atomically thin materials, like semiconducting transition metal dichalcogenides (S-TMDs), are highly sensitive to the environment. This opens up an opportunity to externally control their properties by changing their surroundings. Photoluminescence and reflectance contrast techniques are employed to investigate the effect of metallic substrates on optical properties of MoSe2 monolayer (ML). The optical spectra of MoSe2 MLs deposited on Pt, Au, Mo and Zr have distinctive metal-related lineshapes. In particular, a substantial variation in the intensity ratio and the energy separation between a negative trion and a neutral exciton is observed. It is shown that using metals as substrates affects the doping of S-TMD MLs. The explanation of the effect involves the Schottky barrier formation at the interface between the MoSe2 ML and the metallic substrates. The alignment of energy levels at the metal/semiconductor junction allows for the transfer of charge carriers between them. We argue that a proper selection of metallic substrates can be a way to inject appropriate types of carriers into the respective bands of S-TMDs.

6.
Plant Biol (Stuttg) ; 22(1): 120-128, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31549455

RESUMEN

One of the most fundamental, although controversial, questions related to the evolution of plant mating systems is the distribution of outcrossing rates. Self-compatibility, and especially autonomous self-pollination, can become particularly beneficial in anthropogenically degraded habitats with impoverished pollinator assemblages and increased pollen limitation. In a hand-pollination experiment with 46 meadow plants from the Zelezné hory Mts., Czech Republic, we evaluated the species' ability to adopt different mating systems. For a subset of the species, we also tested seed germination for inbreeding depression. Subsequently, we analysed relationships between the species' mating systems and 12 floral and life-history traits. We found a relatively discrete distribution of the studied species into four groups. Fully and partially self-incompatible species formed the largest group, followed by self-compatible non-selfers and mixed mating species. The germination experiment showed an absence of inbreeding depression in 19 out of 22 examined species. Nectar sugar per flower, nectar sugar per shoot and dichogamy were significant associated with the mating system. Spontaneous selfing ability and self-incompatibility in species of the meadow communities had a discrete distribution, conforming to the general distribution of mating and breeding systems in angiosperms. The low frequency of spontaneous selfers and the lack of inbreeding depression at germination suggest the existence of a selection against selfing at the later ontogenetic stages. Some floral traits, such as the level of dichogamy and amount of nectar reward, may strongly impact the balance between selfing and outcrossing rates in the self-compatible species and thus shape the evolution of mating systems.


Asunto(s)
Pradera , Fenómenos Fisiológicos de las Plantas , Polinización , Flores , Reproducción/fisiología
7.
Phys Rev Lett ; 123(13): 136801, 2019 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-31697524

RESUMEN

We demonstrate that, in monolayers (MLs) of semiconducting transition metal dichalcogenides, the s-type Rydberg series of excitonic states follows a simple energy ladder: ε_{n}=-Ry^{*}/(n+δ)^{2}, n=1,2,…, in which Ry^{*} is very close to the Rydberg energy scaled by the dielectric constant of the medium surrounding the ML and by the reduced effective electron-hole mass, whereas the ML polarizability is accounted for only by δ. This is justified by the analysis of experimental data on excitonic resonances, as extracted from magneto-optical measurements of a high-quality WSe_{2} ML encapsulated in hexagonal boron nitride (hBN), and well reproduced with an analytically solvable Schrödinger equation when approximating the electron-hole potential in the form of a modified Kratzer potential. Applying our convention to other MoSe_{2}, WS_{2}, MoS_{2} MLs encapsulated in hBN, we estimate an apparent magnitude of δ for each of the studied structures. Intriguingly, δ is found to be close to zero for WSe_{2} as well as for MoS_{2} monolayers, what implies that the energy ladder of excitonic states in these two-dimensional structures resembles that of Rydberg states of a three-dimensional hydrogen atom.

8.
Phys Rev Lett ; 123(9): 096803, 2019 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-31524465

RESUMEN

Monolayers of semiconducting transition metal dichalcogenides are two-dimensional direct-gap systems which host tightly bound excitons with an internal degree of freedom corresponding to the valley of the constituting carriers. Strong spin-orbit interaction and the resulting ordering of the spin-split subbands in the valence and conduction bands makes the lowest-lying excitons in WX_{2} (X being S or Se) spin forbidden and optically dark. With polarization-resolved photoluminescence experiments performed on a WSe_{2} monolayer encapsulated in a hexagonal boron nitride, we show how the intrinsic exchange interaction in combination with the applied in-plane and/or out-of-plane magnetic fields enables one to probe and manipulate the valley degree of freedom of the dark excitons.

9.
Nanotechnology ; 29(32): 325705, 2018 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-29781447

RESUMEN

Embedding a WS2 monolayer in flakes of hexagonal boron nitride allowed us to resolve and study the photoluminescence response due to both singlet and triplet states of negatively charged excitons (trions) in this atomically thin semiconductor. The energy separation between the singlet and triplet states has been found to be relatively small reflecting rather weak effects of the electron-electron exchange interaction for the trion triplet in a WS2 monolayer, which involves two electrons with the same spin but from different valleys. Polarization-resolved experiments demonstrate that the helicity of the excitation light is better preserved in the emission spectrum of the triplet trion than in that of the singlet trion. Finally, the singlet (intravalley) trions are found to be observable even at ambient conditions whereas the emission due to the triplet (intervalley) trions is only efficient at low temperatures.

10.
Bratisl Lek Listy ; 119(3): 139-142, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29536741

RESUMEN

AIM: The aim of this study was to analyse the relationship between intracranial pressure (intracranial pressure monitoring) and lactate pyruvate ratio (cerebral microdialysis) in patients with ruptured intracranial aneurysms. METHODS: In a group of fifteen patients, intracranial pressure and lactate/pyruvate ratios were measured and logged in hourly intervals. The relationship between these two variables was subsequently analysed in two ways. 1) Intracranial hypertension (ICP > 20 mmHg) in the presence of energy deprivation (L/P ratio > 30) was noted. 2) The dynamics of L/P ratio changes in relation to immediate ICP and CPP values was analysed. RESULTS: Out of a total of 1873 monitored hours we were able to record lactate/pyruvate ratios higher than 30 in 832 hours (44 %). Of those 832 hours during which lactate/pyruvate ratios were higher than 30, ICP was higher than 20 in 193 hours (23 %). Out of 219 hours of monitoring, in which ICP was higher than 20, a simultaneously increased L/P ratio higher than 30 was recorded in 193 hours (88 %). L/P ratio values above 30 were associated with decreased CPP values (p = 0.04), but not with increased ICP values (p = 0.79). CONCLUSION: Intracranial hypertension coincides with energetic imbalance in approximately one quarter of cases. This points to the shortcomings of the most common form of neuromonitoring in SAH patients - ICP monitoring. This method may not be reliable enough in detecting hypoxic damage, which is the major cause of morbidity and mortality in SAH patients (Fig. 5, Ref. 11).


Asunto(s)
Encéfalo/metabolismo , Hipertensión Intracraneal/metabolismo , Presión Intracraneal , Ácido Láctico/metabolismo , Ácido Pirúvico/metabolismo , Hemorragia Subaracnoidea/metabolismo , Aneurisma Roto/complicaciones , Aneurisma Roto/metabolismo , Aneurisma Roto/fisiopatología , Encéfalo/fisiopatología , Humanos , Aneurisma Intracraneal/complicaciones , Aneurisma Intracraneal/metabolismo , Aneurisma Intracraneal/fisiopatología , Hipertensión Intracraneal/etiología , Hipertensión Intracraneal/fisiopatología , Microdiálisis , Monitoreo Fisiológico , Hemorragia Subaracnoidea/etiología , Hemorragia Subaracnoidea/fisiopatología
11.
Folia Biol (Praha) ; 64(5-6): 195-203, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30938677

RESUMEN

Most people worldwide suffer from dental caries. Only a small part of the population is cariesresistant and the reason for this resistance in unknown. Only a few studies compared the saliva protein composition of persons with carious teeth and persons with no caries. Our study is the first to relate proteomic analysis of the caries aetiology with gender. In this study, we compared the differences in the abundances of proteins in the saliva between cariesresistant and caries-susceptible females and males by nano-liquid chromatography-tandem mass spectrometry (Label-Free Quantitative Proteomics). Our results demonstrate that the observed differences in the protein levels might have an influence on anticaries resistance. A total of 19 potential markers of tooth caries were found, for example proteins S100A8 and annexin A1 with higher expression in the cariessusceptible group in comparison with the caries-free group and mucin-5B, lactoferrin, lysozyme C with higher expression in the caries-free group in comparison with the caries-susceptible group. The presented study is the first complex proteomic and gender project where the saliva protein content of caries-free and caries-susceptible persons were compared by label-free MS. The newly detected potential protein markers of dental caries can be a good basis for further research and for possible future therapeutic use.

12.
Epidemiol Mikrobiol Imunol ; 67(4): 184-190, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30630322

RESUMEN

The paper concerns the epidemiology of Mycobacterium tuberculosis complex (MTBC) members except for M. tuberculosis in the Czech Republic in 2000 to 2016. M. bovis was confirmed in 18 patients. M. caprae was diagnosed in two patients in 2001 and 2016 and M. microti in one patient in 2007. M. africanum was detected in one HIV infected woman from Nigeria in 2011. As regards animals, M. pinnipedii was isolated in 2009 from one Southern sea lion (Otaria flavescens) imported from Germany. In 2002, M. caprae was isolated from two Bactrian camels (Camelus ferus) kept in a zoological garden. M. tuberculosis was isolated from one dog in 2004 and from two domestic pigs in 2007. In both cases, the source of M. tuberculosis was an infected patient. Upon examination of 3 727 environmental samples of water and sediments, none of the MTBC members was detected in the stu-died period. Infected persons coming from M. africanum endemic countries (especially West African countries) and infected animals can be considered as the current risk factors for transmission of MTBC species. If the epidemiological situation remains as it is now, there is no risk of transmission of MTBC species via milk or unpasteurised dairy products. Keywords: mycobacterial ecology - domestic and wild animals - food safety.


Asunto(s)
Mycobacterium , Tuberculosis , Animales , República Checa/epidemiología , Microbiología Ambiental , Femenino , Sedimentos Geológicos/microbiología , Humanos , Mycobacterium tuberculosis , Tuberculosis/epidemiología , Tuberculosis/microbiología
13.
Cesk Slov Oftalmol ; 70(5): 178-82, 2014 Oct.
Artículo en Checo | MEDLINE | ID: mdl-25640040

RESUMEN

AIM: The aim of this study is to evaluate the frequency and efficacy of silicone oil (SO) retinal tamponade in various retinal diseases. The incidence of silicone oil tamponade according to individual indications, incidence of complications and duration of tamponade were evaluated in the study. MATERIAL AND METHODS: A retrospective study included 510 eyes that were operated on pars plana vitrectomy (PPV) from January 2010 to December 2012. In our group we evaluated 241 men and 189 women, age 4-84 years, mean 62 years . Follow-up period was 12 to 48 months, an average of 27.5 months . We evaluated 253 eyes with diabetic retinopathy, 201 eyes with regmatogenous retinal detachment, 34 eyes with endophthalmitis and 22 eyes after the injury. RESULTS: In 253 diabetic retinopathy eyes (DR) silicone oil tamponade was indicated in 56 eyes (22.1 %). Silicone oil removal was done on 22 eyes (39.3 %), the average length of SO tamponade was 9.7 months. After SO removal BCVA (best corrected visual acuity) 0,1 and worse had 12 eyes (54,6 %), 0,2 - 0,4 had 5 eyes (22,7 %) and 0,5 or better had 5 eyes (22,7 %). Permanent SO tamponade was left in 34 diabetic retinopathy eyes (60.7 %). Secondary glaucoma (SG) was present in 40 eyes (71.5 %). In 201 retinal detachment (RD) eyes silicone oil tamponade was used in 76 eyes (37.8 %). Secondary glaucoma was present in 31 eyes (40.8 %). Silicone oil was successfully removed in 40 eyes (52.6 %), the average length of tamponade was 9.2 months. In this group BCVA 0,1 and worse had 22 eyes (55,0 %), 0,2 - 0,4 had 15 eyes (37,5 %) and 0,5 or better had 3 eyes (7,5 %). 36 eyes (47,4 %) RD eyes had permanent silicone oil tamponade. In a group of 34 eyes with endophthalmitis SO tamponade was used in 16 eyes (47 %). Secondary glaucoma was present in 3 eyes (18.8 %). Silicone oil removal we did in 11 eyes (68.8 %), the average length of SO tamponade was 5.5 months. After SO removal BCVA 0,1 and worse had 3 eyes (27,2 %), 0,2 - 0,4 had 4 eyes (36,4 %) and 0,5 or better had 4 eyes (36,4 %). 5 eyes (31.2 %) with endophthalmitis had permanent SO tamponade. Out of 22 eyes with eye injuries SO tamponade was used in 14 eyes (63.6 %). 5 eyes (35.7 %) had secondary glaucoma. In 9 eyes (64.3 %) silicone oil was removed, the average length of tamponade was 9.1 months. In this group BCVA 0,1 and worse had 6 eyes (66,7 %), 0,2-0,4 had 1 eye (11,1 %) and 0,5 or better had 2 eyes (22,2 %). Permanent silicone oil tamponade had 5 eyes (35,7 %). In group of 56 phakic eyes (100 %) with silicone oil tamponade we followed cataract progression. 26 eyes (40 %) had cataract surgery in 6 month follow up, 47 eyes (72.3 %) in 1 year follow up and 57 eyes (87.7 %) had cataract surgery in 3 years follow up. CONCLUSION: Silicone oil tamponade is the method of choice for long-term and stable retinal tamponade, which is important for good functional outcomes of the surgical intervention. The silicone oil tamponade of the retina is nowadays irreplaceable, despite of its potential risks and complications.


Asunto(s)
Desprendimiento de Retina/cirugía , Aceites de Silicona/administración & dosificación , Agudeza Visual , Vitrectomía/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Extracción de Catarata/efectos adversos , Niño , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Desprendimiento de Retina/etiología , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento , Adulto Joven
14.
Ukr Biochem J ; 86(6): 129-38, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25816613

RESUMEN

The investigation of specific activity of ATP sulfurylase and kinetic properties of the enzyme in cell-free extracts of intestinal bacterial strains Desulfovibrio piger Vib-7 and Desulfomicrobium sp. Rod-9 is presented. The microbiological, biochemical, biophysical and statistical methods were used in the work. The optimal temperature (35°C) and pH 8.0-8.5 for enzyme reaction were determined. An analysis of kinetic properties of ATP sulfurylase has been carried out. Initial (instantaneous) reaction velocity (V0), maximum amount of the product of reaction (Pmax), the reaction time (half saturation period, τ) and maximum velocity of the ATP sulfurylase reaction (Vmax) have been defined. Michaelis constants (Km(Sulfate), Km(ATP), Km(APS), and Km(Pyrophosphate)) of the enzyme reaction were demonstrated for both D. piger Vib-7 and Desulfomicrobium sp. Rod-9 intestinal bacterial strains.


Asunto(s)
Proteínas Bacterianas/metabolismo , Desulfovibrio/enzimología , Sulfato Adenililtransferasa/metabolismo , Bacterias Reductoras del Azufre/enzimología , Adenosina Trifosfato/metabolismo , Desulfovibrio/química , Desulfovibrio/aislamiento & purificación , Difosfatos/metabolismo , Pruebas de Enzimas , Humanos , Concentración de Iones de Hidrógeno , Intestino Grueso/microbiología , Cinética , Fracciones Subcelulares/enzimología , Especificidad por Sustrato , Sulfatos/metabolismo , Bacterias Reductoras del Azufre/química , Bacterias Reductoras del Azufre/aislamiento & purificación , Temperatura
15.
Cesk Slov Oftalmol ; 69(3): 102-5, 2013 Aug.
Artículo en Checo | MEDLINE | ID: mdl-24437956

RESUMEN

AIM: To evaluate the results of the idiopathic macular hole (IDM) surgical treatment. Surgery included pars plana vitrectomy (PPV) with the removal (peeling) of internal limiting membrane (ILM) and intraocular tamponade with a diluted expanding gas. MATERIAL AND METHODS: A retrospective study included 100 eyes of 96 patients (10 men and 86 women) with IDM, that were operated at II. Eye Clinic SZU in Banska Bystrica from August 2008 to August 2012. Patients age ranged from 48 to 86 years, average 69.3 years. Mean follow-up time was 39.2 months. All patients underwent PPV with the ILM peeling. Intraocular air tamponade was used in 1-case, 16 % SF6 84-times and 12 % C3F8 15 times. RESULTS: Anatomical success of the operation was evaluated with OCT examination. After primary operation there were 92 (92 %) closed macular holes in our study. In 6 patients (6 %), we decided to reoperate with gas tamponade (SF6 2-times, C3F8 4 times). After the reoperations final anatomical success in our study was 97 eyes (97 %). Functional results we examined with Snellen. Improved best corrected visual acuity (BCVA) was observed in 85 eyes (85 %), no changes in 11 eyes (11 %), and deterioration in 4 eyes (4 %). Improvement in vision was following: 1 line - 18 eyes, 2 lines - 20 eyes, 3 lines - 18 eyes, 4 lines - 11 eyes, 5 or more lines in 18 eyes. CONCLUSION: Pars plana vitrectomy with ILM peeling and gas tamponade is highly effective and safe treatment of idiopathic macular hole.Key words: idiopathic macular hole, pars plana vitrectomy, expanding gas.


Asunto(s)
Perforaciones de la Retina/cirugía , Vitrectomía/métodos , Anciano , Anciano de 80 o más Años , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Perforaciones de la Retina/diagnóstico , Perforaciones de la Retina/fisiopatología , Estudios Retrospectivos , Tomografía de Coherencia Óptica , Resultado del Tratamiento , Agudeza Visual
16.
Cesk Slov Oftalmol ; 68(1): 3-8, 10, 2012 Feb.
Artículo en Eslovaco | MEDLINE | ID: mdl-22679691

RESUMEN

AIM: To evaluate the importance and benefits of using gases in vitreoretinal surgery. MATERIAL AND METHODS: The gases represent a wide group of substances used in eye surgery for more than 100 years. The role of intraocular gases in vitreoretinal surgery is irreplaceable. Their use is still considered to be the "gold standard". An important step in eye surgery was the introduction of expanding gases--sulfur hexafluoride and perfluorocarbons into routine clinical practice. The most common indications for the use of intraocular gases are: retinal detachment, idiopathic macular hole, complications of vitreoretinal surgery and others. RESULTS AND CONCLUSIONS: The introduction of intraocular gases into routine clinical practice, along with other modern surgical techniques resulted in significant improvement of postoperative outcomes in a wide range of eye diseases. Understanding the principles of intraocular gases use brings the benefits to the patient and physician as well. Due to their physical and chemical properties they pose far the best and most appropriate variant of intraocular tamponade. Gases also bring some disadvantages, such as difficulties in detailed fundus examination, visual acuity testing, ultrasonographic examination, difficulties in application of intravitreal drugs or reduced possibility of retina laser treatment. The gases significantly change optical system properties of the eye. The use of gases in vitreoretinal surgery has significantly increased success rate of retinal detachment surgery, complicated posterior segment cases, trauma, surgery of the macula and other diseases.


Asunto(s)
Gases/administración & dosificación , Procedimientos Quirúrgicos Oftalmológicos/métodos , Enfermedades de la Retina/cirugía , Cuerpo Vítreo/cirugía , Humanos
18.
Physiol Res ; 59 Suppl 1: S33-S41, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20626218

RESUMEN

It has been shown that besides positron emission tomography, single photon emission computed tomography and magnetic resonance imaging; contrast echocardiography can be used for qualitative and quantitative myocardial perfusion assessment. In this review, the properties of ultrasound contrast agents, imaging techniques and acquisition methods are shortly described and the possibilities of perfusion echocardiography are summarized. The main focus is put on the description of three perfusion models: mathematical models, physical models assuming an ideal inflow and physical models including inflow measurement.


Asunto(s)
Circulación Coronaria , Ecocardiografía , Imagen de Perfusión Miocárdica/métodos , Animales , Medios de Contraste , Humanos , Interpretación de Imagen Asistida por Computador , Modelos Cardiovasculares , Valor Predictivo de las Pruebas
19.
Folia Biol (Praha) ; 56(3): 124-30, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20653997

RESUMEN

Flavonoids are commonly studied for their anti-inflammatory effects; however, this is the first paper describing the possible antiphlogistic activity of a geranylated flavanone. This study focused on the ability of diplacone to modulate the gene expression of pro-inflammatory tumour necrosis factor alpha and monocyte chemoattractant protein 1, and of anti-inflammatory zinc finger protein 36. The action of diplacone was also compared with that of conventional drug indomethacin. Human monocyte-derived macrophages of the human monocytic leukaemia cell line were pretreated with diplacone or indomethacin. Subsequently, inflammatory reaction was induced by lipopolysaccharide, and changes of tumour necrosis factor alpha, monocyte chemoattractant protein 1 and zinc finger protein 36 gene expression at the transcriptional level were measured. In this model, diplacone significantly down-regulated the expression of tumour necrosis factor alpha and monocyte chemoattractant protein 1 and up-regulated the zinc finger protein 36 expression. This makes diplacone a promising molecule for treatment of the inflammatory stage of diseases. The effect of diplacone in decreasing lipopolysaccharide-induced inflammatory gene expression is in many ways similar to that of the conventional drug indomethacin.


Asunto(s)
Flavonoides/farmacología , Lipopolisacáridos/farmacología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Línea Celular , Quimiocina CCL2/genética , Flavonoides/química , Humanos , Estructura Molecular , Factor de Necrosis Tumoral alfa/genética
20.
Physiol Res ; 59(2): 225-232, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-19537930

RESUMEN

The aim of the present work was to investigate a new mechanism likely contributing to the toxic action of acetaminophen, especially to explore the possible inhibition of glutathione reductase through an acetaminophen-glutathione conjugate (APAP-SG). APAP-SG conjugate was synthesized by organic synthesis and purified by column chromatography. The inhibitory effect of the conjugate on two types of glutathione reductase (from yeasts and rat hepatocytes) was tested spectro-photometrically. We found that the enzyme activity was reduced similarly after the treatment with 2.96 mM acetaminophen-glutathione conjugate in both yeast and hepatocyte glutathione reductases (GR); the enzyme activity was inhibited to 52.7+/-1.5 % (2.4+/-0.3 mU/ml) in yeast GR (control activity was 5.6+/-0.3 mU/ml) and to 48.1+/-8.8 % (2.2+/-0.2 mU/ml) in rat hepatocytes lysate GR (control activity was 5.2+/-0.2 mU/ml). In addition, the enzyme activity (from hepatocytes lysate) was decreased to 79+/-7 %, 67+/-2 % and 39+/-7 %, in 0.37, 1.48 and 3.7 mM concentration of the conjugate, respectively. We found that glutathione reductase, the essential enzyme of the antioxidant system, was dose-dependently inhibited by the product of acetaminophen metabolism - the conjugate of acetaminophen and glutathione.


Asunto(s)
Acetaminofén/toxicidad , Analgésicos no Narcóticos/toxicidad , Glutatión Reductasa/antagonistas & inhibidores , Glutatión/toxicidad , Hepatocitos/efectos de los fármacos , Acetaminofén/síntesis química , Analgésicos no Narcóticos/síntesis química , Animales , Células Cultivadas , Relación Dosis-Respuesta a Droga , Combinación de Medicamentos , Activación Enzimática/efectos de los fármacos , Glutatión/síntesis química , Glutatión Reductasa/metabolismo , Hepatocitos/enzimología , Hepatocitos/patología , Técnicas In Vitro , Masculino , Ratas , Ratas Wistar
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