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1.
Prehosp Emerg Care ; 27(5): 623-629, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36053543

RESUMEN

OBJECTIVE: The Hunter-8 prehospital stroke scale predicts large vessel occlusion in hyperacute ischemic stroke patients (LVO) at hospital admission. We wished to test its performance in the hands of paramedics as part of a prehospital triage algorithm. We aimed to determine (a) the proportion of patients identified by the Hunter-8 algorithm, receiving reperfusion therapies, (b) whether a call to stroke team improved this, and (c) performance for LVO detection using an expanded LVO definition. METHODS: A prehospital workflow combining pre-morbid functional status, time from symptom onset, and the Hunter-8 scale was implemented from July 2019. A telephone call to the stroke team was prompted for potential treatment candidates. Classic LVO was defined as a proximal middle cerebral artery (MCA-M1), terminal internal carotid artery, or tandem occlusion. Extended LVO added proximal MCA-M2 and basilar occlusions. RESULTS: From July 2019 to April 2021, there were 363 Hunter-8 activations, 320 analyzed: 181 (56.6%) had confirmed ischemic strokes, 13 (4.1%) transient ischemic attack, 91 (28.5%) stroke mimics, and 35 (10.9%) intracranial hemorrhage. Fifty-two patients (16.3%) received reperfusion therapies, 35 with Hunter-8 ≥ 8. The stroke doctor changed the final destination for 76 patients (23.7%), and five received reperfusion therapies. The AUCs for classic and extended LVO were 0.73 (95% CI 0.66-0.79) and 0.72 (95% CI 0.65-0.77), respectively. CONCLUSION: The Hunter-8 workflow resulted in 28.7% of confirmed ischemic stroke patients receiving reperfusion therapies, with no secondary transfers to the comprehensive stroke center. The role of communication with stroke team needs to be further explored.


Asunto(s)
Isquemia Encefálica , Servicios Médicos de Urgencia , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , Triaje/métodos , Isquemia Encefálica/diagnóstico , Isquemia Encefálica/terapia , Flujo de Trabajo , Servicios Médicos de Urgencia/métodos , Accidente Cerebrovascular/diagnóstico , Accidente Cerebrovascular/terapia , Hemorragias Intracraneales
2.
Mol Pain ; 15: 1744806919839860, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30845881

RESUMEN

A well-recognized relationship exists between aging and increased susceptibility to chronic pain conditions, underpinning the view that pain signaling pathways differ in aged individuals. Yet despite the higher prevalence of altered pain states among the elderly, the majority of preclinical work studying mechanisms of aberrant sensory processing are conducted in juvenile or young adult animals. This mismatch is especially true for electrophysiological studies where patch clamp recordings from aged tissue are generally viewed as particularly challenging. In this study, we have undertaken an electrophysiological characterization of spinal dorsal horn neurons in young adult (3-4 months) and aged (28-32 months) mice. We show that patch clamp data can be routinely acquired in spinal cord slices prepared from aged animals and that the excitability properties of aged dorsal horn neurons differ from recordings in tissue prepared from young animals. Specifically, aged dorsal horn neurons more readily exhibit repetitive action potential discharge, indicative of a more excitable phenotype. This observation was accompanied by a decrease in the amplitude and charge of spontaneous excitatory synaptic input to dorsal horn neurons and an increase in the contribution of GABAergic signaling to spontaneous inhibitory synaptic input in aged recordings. While the functional significance of these altered circuit properties remains to be determined, future work should seek to assess whether such features may render the aged dorsal horn more susceptible to aberrant injury or disease-induced signaling and contribute to increased pain in the elderly.


Asunto(s)
Envejecimiento/metabolismo , Transducción de Señal , Asta Dorsal de la Médula Espinal/metabolismo , Animales , Neuronas GABAérgicas/metabolismo , Masculino , Ratones Endogámicos C57BL , Inhibición Neural
3.
BJOG ; 126(8): 1025-1031, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30811810

RESUMEN

OBJECTIVE: Pregnancies in women with Loeys-Dietz syndrome (LDS) are rare and are typically documented in case reports only. Early reports suggested high rates of maternal complications during pregnancy and the puerperium, including aortic dissection and uterine rupture, but information on fetal outcomes was very limited. DESIGN: A retrospective cohort study. SETTING: Eight specialist UK centres. SAMPLE: Pregnant women with LDS. METHODS: Data was collated on cardiac, obstetric, and neonatal outcomes. MAIN OUTCOME MEASURES: Maternal and perinatal outcomes in pregnancies complicated by LDS. RESULTS: Twenty pregnancies in 13 women with LDS were identified. There was one miscarriage, one termination of pregnancy, and 18 livebirths. In eight women the diagnosis was known prior to pregnancy but only one woman had preconception counselling. In four women the diagnosis was made during pregnancy through positive genotyping, and the other was diagnosed following delivery. Five women had a family history of aortic dissection. There were no aortic dissections in our cohort during pregnancy or postpartum. Obstetric complications were common, including postpartum haemorrhage (33%) and preterm delivery (50%). In all, 14/18 (78%) of deliveries were by elective caesarean section, at a median gestational age at delivery of 37 weeks. Over half the infants (56%) were admitted to the neonatal unit following delivery. CONCLUSION: Women with LDS require multidisciplinary specialist management throughout pregnancy. Women should be referred for preconception counselling to make informed decisions around pregnancy risk and outcomes. Early elective preterm delivery needs to be balanced against a high infant admission rate to the neonatal unit. TWEETABLE ABSTRACT: Pregnancy outcomes in women with Loeys-Dietz syndrome.


Asunto(s)
Síndrome de Loeys-Dietz/complicaciones , Complicaciones del Embarazo/etiología , Resultado del Embarazo , Adulto , Parto Obstétrico/métodos , Femenino , Humanos , Recién Nacido , Hemorragia Posparto/etiología , Embarazo , Nacimiento Prematuro/etiología , Estudios Retrospectivos , Factores de Riesgo , Reino Unido/epidemiología
4.
HIV Med ; 19(10): 698-707, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-30062761

RESUMEN

OBJECTIVES: The aim of the study was to assess the interest to combine cytological examination and human papillomavirus (HPV) typing of anal and cervical Papanicolaou (Pap) smears of HIV-infected patients on combination antiretroviral therapy (cART), to evaluate whether differences in prevalence exist between anal and cervical squamous intraepithelial lesions in patients with high-risk oncogenic HPV infection. METHODS: Anal and/or cervical Pap smears were obtained by anoscopy and/or colposcopy in 238 subjects recruited consecutively in 2015: anal smears were obtained from 48 male and female patients [42 men; 35 men who have sex with men (MSM)] and cervical smears from 190 female patients. Cytological Bethesda classification was coupled with HPV typing. HPV typing was performed, on the same smears, using the Xpert® HPV Assay, which detects only high-risk HPV (hrHPV), and the Anyplex® II HPV28 Detection assay, which detects hrHPV and low-risk (lr) HPV. RESULTS: Our data showed clear-cut differences between the anal and cervical samples. Compared with the cervical samples, the anal samples exhibited (1) more numerous cytological lesions, which were histologically proven; (2) a higher hrHPV infection prevalence; (3) a higher prevalence of multiple hrHPV coinfections whatever HPV typing kit was used; (4) a predominance of HPV16 and HPV18/45 types. Overall, there was an almost perfect agreement between the two HPV typing assays (absolute agreement = 90.3%). CONCLUSIONS: Co-testing consisting of cytology and HPV typing is a useful screening tool in the HIV-infected population on cART. It allows detection of prevalence differences between anal and cervical HPV-related lesions. As recently recommended, anal examination should be regularly performed especially in HIV-infected MSM but also in HIV-infected women with genital hrHPV lesions.


Asunto(s)
Antirretrovirales/uso terapéutico , Coinfección/diagnóstico , Técnicas Citológicas/métodos , Infecciones por VIH/complicaciones , Técnicas de Diagnóstico Molecular/métodos , Papillomaviridae/aislamiento & purificación , Infecciones por Papillomavirus/diagnóstico , Adulto , Anciano , Canal Anal/patología , Canal Anal/virología , Cuello del Útero/patología , Cuello del Útero/virología , Coinfección/virología , Femenino , Genotipo , Infecciones por VIH/tratamiento farmacológico , Humanos , Masculino , Tamizaje Masivo/métodos , Persona de Mediana Edad , Papillomaviridae/clasificación , Papillomaviridae/genética , Infecciones por Papillomavirus/virología , Prevalencia , Estudios Prospectivos , Adulto Joven
5.
Brain Behav Immun ; 67: 299-307, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28911981

RESUMEN

Experimental stroke leads to microglia activation and progressive neuronal loss at sites of secondary neurodegeneration (SND). These lesions are remote from, but synaptically connected to, primary infarction sites. Previous studies have demonstrated that immune cells are present in sites of infarction in the first hours and days after stroke, and are associated with increased neurodegeneration in peri-infarct regions. However, it is not known whether immune cells are also present in more distal sites where SND occurs. Our study aimed to investigate whether immune cells are present in sites of SND and, if so, how these cell populations compare to those in the peri-infarct zone. Cells were isolated from the thalamus, the main site of SND, and remaining brain tissue 14days post-stroke. Analysis was performed using flow cytometry to quantify microglia, myeloid cell and lymphocyte numbers. We identified a substantial infiltration of immune cells in the ipsilateral (stroked) compared to the contralateral (control) thalamus, with a significant increase in the percentage of CD4+ and CD8+ T cells. This result was further quantified using immunofluorescent labelling of fixed tissue. In the remaining ipsilateral hemisphere tissue, there were significant increases in the frequency of CD4+ and CD8+ T lymphocytes, B lymphocytes, Ly6G+ neutrophils and both Ly6G-Ly6CLO and Ly6G-Ly6CHI monocytes. Our results indicate that infiltrating immune cells persist in ischemic tissue after the acute ischemic phase, and are increased in sites of SND. Importantly, immune cells have been shown to play pivotal roles in both damage and repair processes after stroke. Our findings indicate that immune cells may also be involved in the pathogenesis of SND and further clinical studies are warranted to characterise the nature of inflammatory cell infiltrates in human disease.


Asunto(s)
Isquemia Encefálica/inmunología , Encéfalo/inmunología , Linfocitos/metabolismo , Microglía/inmunología , Células Mieloides/inmunología , Accidente Cerebrovascular/inmunología , Animales , Encéfalo/metabolismo , Encéfalo/patología , Isquemia Encefálica/complicaciones , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patología , Masculino , Ratones Endogámicos C57BL , Microglía/metabolismo , Células Mieloides/metabolismo , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/metabolismo , Accidente Cerebrovascular/patología
6.
Phys Rev Lett ; 116(10): 106101, 2016 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-27015492

RESUMEN

The strong interaction at an interface between a substrate and thin film leads to epitaxy and provides a means of inducing structural changes in the epitaxial film. These induced material phases often exhibit technologically relevant electronic, magnetic, and functional properties. The 2×1 surface of a Ge(001) substrate applies a unique type of epitaxial constraint on thin films of the perovskite oxide BaTiO_{3} where a change in bonding and symmetry at the interface leads to a non-bulk-like crystal structure of the BaTiO_{3}. While the complex crystal structure is predicted using first-principles theory, it is further shown that the details of the structure are a consequence of hidden phases found in the bulk elastic response of the BaTiO_{3} induced by the symmetry of forces exerted by the germanium substrate.

7.
Phys Rev Lett ; 117(14): 147401, 2016 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-27740843

RESUMEN

Resonant inelastic x-ray scattering is used to investigate the electronic origin of orbital polarization in nickelate heterostructures taking LaTiO_{3}-LaNiO_{3}-3×(LaAlO_{3}), a system with exceptionally large polarization, as a model system. We find that heterostructuring generates only minor changes in the Ni 3d orbital energy levels, contradicting the often-invoked picture in which changes in orbital energy levels generate orbital polarization. Instead, O K-edge x-ray absorption spectroscopy demonstrates that orbital polarization is caused by an anisotropic reconstruction of the oxygen ligand hole states. This provides an explanation for the limited success of theoretical predictions based on tuning orbital energy levels and implies that future theories should focus on anisotropic hybridization as the most effective means to drive large changes in electronic structure and realize novel emergent phenomena.

8.
Colorectal Dis ; 18(10): 997-1004, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26896041

RESUMEN

AIM: Anal screening is recommended in HIV-positive patients, especially men who have sex with men (MSM), due to an increased incidence of anal cancer. The optimal screening methods are not generally agreed. METHOD: Screening for anal lesions by anorectal examination, including anoscopy, was offered to HIV-positive outpatients in a tertiary care university hospital regardless of gender or sexual orientation. RESULTS: Among the 1206 screened patients (701 MSM, 247 heterosexual men, 258 women), 311 (26%) had histologically proven lesions related to human papilloma virus (HPV) (34% MSM, 14% heterosexual men, 14% women); 123 (10%) had low-grade dysplasia and 70 (6%) high-grade dysplasia. Seven anal cancers were also diagnosed. Determinants of any lesion were age < 45 years [OR = 1.56 (95% CI, 1.16-2.11)], a CD4 count of < 200/mm3 [OR = 2.54 (1.71-3.78)], receptive anal intercourse [OR =3.03 (2.06-4.47)], sub-Saharan African origin [OR = 0.53 (0.33-0.85)], and history of HPV-related lesion [OR = 1.84 (1.35-2.51)]. These determinants were similar for all different grades of dysplasia. In patient subgroup analysis, receptive anal intercourse, the CD4 cell count and a history of HPV lesions were determinants of HPV-positivity in all patients, whereas age was only a determinant in men. CONCLUSION: Anoscopy is an alternative method for anal screening in an HIV-positive population. This screening has to be compared with other tools in populations at high risk of anal cancer.


Asunto(s)
Enfermedades del Ano/diagnóstico , Neoplasias del Ano/diagnóstico , Infecciones por VIH/complicaciones , Lesiones Precancerosas/diagnóstico , Proctoscopía/métodos , Adulto , Canal Anal/diagnóstico por imagen , Enfermedades del Ano/virología , Neoplasias del Ano/virología , Detección Precoz del Cáncer/métodos , Femenino , Humanos , Masculino , Tamizaje Masivo/métodos , Persona de Mediana Edad , Lesiones Precancerosas/virología , Factores de Riesgo , Conducta Sexual , Parejas Sexuales
9.
Biochemistry ; 54(2): 221-39, 2015 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-25486224

RESUMEN

The ß-barrel nitrophorin (NP) heme proteins are found in the saliva of the blood-sucking insect Rhodnius prolixus, which synthesizes and stores nitric oxide (NO) in the salivary glands. NO is bound to iron of the NPs and is released by dilution and an increase in pH when the insect spits its saliva into the tissues of a victim, to aid in obtaining a blood meal. In the adult insect, there are four nitrophorins, NP1-NP4, which have sequence similarities in two pairs, NP1 and NP4 (90% identical) and NP2 and NP3 (80% identical). The available crystal structures of NP4 have been used to propose that pH-dependent changes in the conformation of two loops between adjacent ß-strands at the front opening of the protein, the A-B and G-H loops, determine the rate of NO release. At pH 7.3, NP4 releases NO 17 times faster than NP2 does. In this work, the aqua complexes of NP4 and NP2 have been investigated by nuclear magnetic resonance (NMR) relaxation measurements to probe the pico- to nanosecond and micro- to millisecond time scale motions at two pH values, 6.5 and 7.3. It is found that NP4-OH2 is fairly rigid and only residues in the loop regions show dynamics at pH 6.5; at pH 7.3, much more dynamics of the loops and most of the ß-strands are observed while the α-helices remain fairly rigid. In comparison, NP2-OH2 shows much less dynamics, albeit somewhat more than that of the previously reported NP2-NO complex [Muthu, D., Berry, R. E., Zhang, H., and Walker, F. A. (2013) Biochemistry 52, 7910-7925]. The reasons for this major difference between NP4 and NP2 are discussed.


Asunto(s)
Hemoproteínas/química , Proteínas de Insectos/química , Rhodnius/química , Proteínas y Péptidos Salivales/química , Animales , Concentración de Iones de Hidrógeno , Simulación de Dinámica Molecular , Resonancia Magnética Nuclear Biomolecular , Conformación Proteica
10.
Biochemistry ; 54(2): 208-20, 2015 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-25489673

RESUMEN

Nitrophorin 4, one of the four NO-carrying heme proteins from the salivary glands of Rhodnius prolixus, forms a homodimer at pH 5.0 with a Kd of ∼8 µM. This dimer begins to dissociate at pH 5.5 and is completely dissociated to monomer at pH 7.3, even at 3.7 mM. The dimer is significantly stabilized by binding NO to the heme and at pH 7.3 would require dilution to well below 0.2 mM to completely dissociate the NP4-NO homodimer. The primary techniques used for investigating the homodimer and the monomer-dimer equilibrium were size-exclusion fast protein liquid chromatography at pH 5.0 and (1)H{(15)N} heteronuclear single-quantum coherence spectroscopy as a function of pH and concentration. Preparation of site-directed mutants of NP4 (A1K, D30A, D30N, V36A/D129A/L130A, K38A, R39A, K125A, K125E, D132A, L133V, and K38Q/R39Q/K125Q) showed that the N-terminus, D30, D129, D132, at least one heme propionate, and, by association, likely also E32 and D35 are involved in the dimerization. The "closed loop" form of the A-B and G-H flexible loops of monomeric NP4, which predominates in crystal structures of the monomeric protein reported at pH 5.6 but not at pH 7.5 and which involves all of the residues listed above except D132, is required for dimer formation. Wild-type NP1 does not form a homodimer, but NP1(K1A) and native N-terminal NP1 form dimers in the presence of NO. The homodimer of NP1, however, is considerably less stable than that of NP4 in the absence of NO. This suggests that additional aspartate or glutamate residues present in the C-terminal region of NP4, but not NP1, are also involved in stabilizing the dimer.


Asunto(s)
Hemoproteínas/química , Proteínas de Insectos/química , Multimerización de Proteína , Rhodnius/química , Proteínas y Péptidos Salivales/química , Animales , Cristalografía por Rayos X , Hemoproteínas/genética , Concentración de Iones de Hidrógeno , Proteínas de Insectos/genética , Modelos Moleculares , Mutagénesis Sitio-Dirigida , Mutación Puntual , Rhodnius/genética , Proteínas y Péptidos Salivales/genética
11.
Phys Rev Lett ; 114(2): 026801, 2015 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-25635555

RESUMEN

We experimentally demonstrate a novel approach to substantially modify orbital occupations and symmetries in electronically correlated oxides. In contrast to methods using strain or confinement, this orbital tuning is achieved by exploiting charge transfer and inversion symmetry breaking using atomically layered heterostructures. We illustrate the technique in the LaTiO_{3}-LaNiO_{3}-LaAlO_{3} system; a combination of x-ray absorption spectroscopy and ab initio theory reveals electron transfer and concomitant polar fields, resulting in a ∼50% change in the occupation of Ni d orbitals. This change is sufficiently large to remove the orbital degeneracy of bulk LaNiO_{3} and creates an electronic configuration approaching a single-band Fermi surface. Furthermore, we theoretically show that such three-component heterostructuring is robust and tunable by choice of insulator in the heterostructure, providing a general method for engineering orbital configurations and designing novel electronic systems.

12.
Phys Chem Chem Phys ; 17(14): 9488-98, 2015 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-25767833

RESUMEN

The impact of ferroelectric polarization on the chemical and electronic properties of atomically thin layers of non-polar chromium oxide deposited on positively and negatively poled LiNbO3(0001) was studied. Chromium(III) oxide readily forms on LiNbO3; however, annealing at high temperatures was required to maintain well-ordered films as the thickness increased. Prolonged heating at these temperatures caused Cr diffusion into the LiNbO3 substrate. Comparing Cr 2p X-ray photoelectron spectroscopy (XPS) peak positions as a function of temperature and substrate polarization revealed no evidence of shifts from the peak positions expected for Cr2O3. The lack of any band offset between Cr2O3 on the oppositely poled surface suggests that charge compensation of the ferroelectric substrate occurs at least predominantly at the surface of the film, as opposed to the film-substrate interface. No evidence of shifts due to oxidation or reduction of the Cr was observed indicating that charge compensation did not involve a change in the ionic state of the Cr. Exposing the films to reactive oxygen species emitted from an oxygen plasma, however, caused a distinct high binding energy shoulder on the Cr 2p3/2 XPS peaks that could be associated with oxygen adsorption on surface Cr and concomitant oxidation to Cr(5+). This feature was used to gauge the concentration of O adatoms on the surfaces as a function of temperature for oppositely poled substrates; these measurements did not reveal any significant polarization dependence for oxygen desorption. Further, temperature programmed desorption measurements for a Cr2O3 film on α-Al2O3 showed a similar trend in O2 desorption. Therefore, it is concluded that the reactivity of Cr2O3 toward O is at least largely independent of substrate polarization despite data suggestive of charge compensation at the film surfaces.

13.
Eur J Appl Physiol ; 115(7): 1577-88, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25736783

RESUMEN

PURPOSE: Exercise-induced muscle damage (EIMD) has recently been shown to increase heat strain during exercise heat stress (HS), and represents a risk factor for exertional heat illness (EHI). We hypothesised that a repeated bout of EIMD blunts the increase in rectal temperature (T re) during subsequent endurance exercise in the heat. METHODS: Sixteen non-heat-acclimated males were randomly allocated to EIMD (n = 9) or control (CON, n = 7). EIMD performed a downhill running treatment at -10 % gradient for 60 min at 65 % [Formula: see text]O2max in 20 °C, 40 % RH. CON participants performed the same treatment but at +1 % gradient. Following treatment, participants rested for 30 min, then performed HS (+1 % gradient running for 40 min at 65 % [Formula: see text]O2max in 33 °C, 50 % RH) during which thermoregulatory measures were assessed. Both groups repeated the treatment and subsequent HS 14 days later. Isometric quadriceps strength was assessed at baseline, and 48 h post-treatment. RESULTS: The decrease in leg strength 48 h post-EIMD trial 1 (-7.5 %) was absent 48 h post-EIMD trial 2 (+2.9 %) demonstrating a repeated bout effect. Final T re during HS was lower following EIMD trial 2 (39.25 ± 0.47 °C) compared with EIMD trial 1 (39.59 ± 0.49 °C, P < 0.01), with CON showing no difference. Thermal sensation and the T re threshold for sweating onset were also lower during HS on EIMD trial 2. CONCLUSION: The repeated bout effect blunted the increase in heat strain during HS conducted after EIMD. Incorporating a muscle-damaging bout into training could be a strategy to reduce the risk of EHI and improve endurance performance in individuals undertaking heavy exercise with an eccentric component in the heat.


Asunto(s)
Ejercicio Físico/fisiología , Trastornos de Estrés por Calor/fisiopatología , Músculo Esquelético/fisiopatología , Carrera/fisiología , Terapia por Ejercicio/métodos , Trastornos de Estrés por Calor/etiología , Trastornos de Estrés por Calor/terapia , Calor , Humanos , Masculino , Músculo Esquelético/fisiología , Consumo de Oxígeno/fisiología , Sudoración/fisiología , Sensación Térmica/fisiología , Adulto Joven
14.
Proc Natl Acad Sci U S A ; 109(7): 2660-5, 2012 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-22308405

RESUMEN

Globins constitute a superfamily of proteins widespread in all kingdoms of life, where they fulfill multiple functions, such as efficient O(2) transport and modulation of nitric oxide bioactivity. In plants, the most abundant Hbs are the symbiotic leghemoglobins (Lbs) that scavenge O(2) and facilitate its diffusion to the N(2)-fixing bacteroids in nodules. The biosynthesis of Lbs during nodule formation has been studied in detail, whereas little is known about the green derivatives of Lbs generated during nodule senescence. Here we characterize modified forms of Lbs, termed Lba(m), Lbc(m), and Lbd(m), of soybean nodules. These green Lbs have identical globins to the parent red Lbs but their hemes are nitrated. By combining UV-visible, MS, NMR, and resonance Raman spectroscopies with reconstitution experiments of the apoprotein with protoheme or mesoheme, we show that the nitro group is on the 4-vinyl. In vitro nitration of Lba with excess nitrite produced several isomers of nitrated heme, one of which is identical to those found in vivo. The use of antioxidants, metal chelators, and heme ligands reveals that nitration is contingent upon the binding of nitrite to heme Fe, and that the reactive nitrogen species involved derives from nitrous acid and is most probably the nitronium cation. The identification of these green Lbs provides conclusive evidence that highly oxidizing and nitrating species are produced in nodules leading to nitrosative stress. These findings are consistent with a previous report showing that the modified Lbs are more abundant in senescing nodules and have aberrant O(2) binding.


Asunto(s)
Fabaceae/química , Hemo/química , Leghemoglobina/química , Especies de Nitrógeno Reactivo/química , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Espectrofotometría Ultravioleta
15.
J Biol Inorg Chem ; 19(4-5): 577-93, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24292244

RESUMEN

Nitrophorin 2 (NP2), one of the four NO-storing and NO-releasing proteins found in the saliva of the blood-sucking bug Rhodnius prolixus, has a more ruffled heme and a high preference for a particular heme orientation (B) compared with nitrophorin 1 and nitrophorin 4, which show not a preference (A to B ratio of approximately 1:1), suggesting that it fits more tightly in the ß-barrel protein. In this work we have prepared a series of "belt" mutants of NP2(D1A) and (ΔM0)NP2 aimed at reducing the size of aromatic or other residues that surround the heme, and investigated them as the high-spin aqua and low-spin N-methylimidazole complexes. The belt mutants included Y38A, Y38F, F42A, F66A, Y85A, Y85F, Y104A, I120T, and a triple mutant of NP2(D1A), the F42L, L106F, I120T mutant. Although I120 has been mainly considered to be a distal pocket residue, CδH3 of I120 lies directly above the heme 3-methyl, at 2.67 Å, of heme orientation B, or the 2-vinyl of A, and it thus plays a role as a belt mutant, a role that turns out to be extremely important in creating the strong favoring of the B heme orientation [A to B ratio of 1:14 for NP2(D1A) or 1:12 for (ΔM0)NP2]. The results show that the 1D (1)H NMR spectra of the high-spin forms are quite sensitive to changes in the shape of the heme binding cavity. The single mutation I120T eliminates the favorability of the B heme orientation by producing a heme A to B orientation ratio of 1:1, whereas the single mutation F42A reverses the heme orientation from an A to B ratio of 1:14 seen for NP2(D1A) to 10:1 for NP2(D1A,F42A). The most extreme ratio was found for the triple mutant of NP2(D1A), NP2(D1A,F42L,L105F,I120T), in which the A to B ratio is approximately 25:1, a ΔG change of about -3.5 kcal/mol or -14.1 kJ/mol with respect to NP2(D1A). The seating of the heme is modified as well in that mutant and in several others, by rotations of the heme by up to 4° from the seating observed in NP2(D1A), in order to relieve steric interactions between a vinyl ß-carbon and a protein side chain, or to fill a cavity created by replacing a large protein side chain by a much smaller one; the latter was observed for all tyrosine to alanine mutants. These relatively small changes in seating have a measurable effect on the NMR spectra of the mutants, but are indeed minor in terms of overall seating and reactivity of the NP2(D1A) protein. The (1)H NMR resonances of the hemin substituents of the low-spin N-methylimidazole complexes of NP2(D1A,F42L,L105F,I120T) as well as NP2(D1A,I120T), NP2(D1A,Y104A), and NP2(D1A,F42A) have been assigned using natural abundance (1)H{(13)C} heteronuclear multiple quantum correlation and (1)H-(1)H nuclear Overhauser effect spectroscopy spectra.


Asunto(s)
Hemo/química , Hemo/metabolismo , Hemoproteínas/química , Hemoproteínas/metabolismo , Espectroscopía de Resonancia Magnética/métodos , Proteínas y Péptidos Salivales/química , Proteínas y Péptidos Salivales/metabolismo , Hemoproteínas/genética , Mutagénesis Sitio-Dirigida , Proteínas y Péptidos Salivales/genética , Termodinámica
16.
Brain Behav Immun ; 37: 1-14, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24412599

RESUMEN

Microglia are unique cells within the central nervous system because of their biophysical independence. As a result of this unusual property the cells must undergo significant structural remodelling in order to engage and connect with other elements within the central nervous system. Efficient remodelling is required for all activities that microglia are involved in ranging from monitoring synaptic information flow through to phagocytosis of tissue debris. Despite the fact that morphological remodelling is a pre-requisite to all microglial activities, relatively little research has been undertaken on the topic. This review examines what is known about how microglia transform themselves during development, under physiological conditions in response to changes in neuronal activity, and under pathological circumstances. Specific attention is given to exploring a variety of models that have been proposed to account for microglial transformation as well as the signals that are known to trigger these transformations.


Asunto(s)
Microglía/citología , Microglía/fisiología , Animales , Humanos , Modelos Neurológicos , Enfermedades del Sistema Nervioso/patología
17.
Br J Dermatol ; 171(5): 1197-205, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24813676

RESUMEN

BACKGROUND: Patients with psoriasis suffer from chronic skin disease and impaired quality of life. With a prevalence of 1-3% of the population, psoriasis is one of the most common chronic inflammatory autoimmune diseases. Fumaric acid esters (Fumaderm(®)) are approved for the treatment of psoriasis in Germany, but regular Fumaderm therapy with six tablets per day is often limited due to adverse events. OBJECTIVES: This observational study recorded data on quality of life, treatment efficacy and drug dosing in patients suffering from psoriasis treated with Fumaderm under conditions of daily practice in 78 dermatological centres. PATIENTS AND METHODS: In this prospective, multicentre, noninterventional trial we included adult patients with severe plaque psoriasis under outpatient conditions receiving Fumaderm according to the current summary of product characteristics for systemic treatment of psoriasis. At baseline and after 3, 6 and 12 months the dosing regimen under daily conditions, Dermatology Life Quality Index (DLQI) and clinical efficacy with the Psoriasis Area and Severity Index (PASI) were documented. RESULTS: A total of 249 patients were included. The mean DLQI score at study entry was 9·95; the mean PASI was 16·8. The average treatment dose of Fumaderm was 2·8 tablets daily. More than 70% of patients were treated with one to three tablets daily and < 30% were treated with a dose ranging from four to six tablets daily. DLQI and PASI improved in the entire study population by 67·2% and 66·6%, respectively. Specifically, when analysing patients who started Fumaderm within 4 weeks before baseline the mean DLQI score decreased from 11·8 to 2·9 (75% reduction) and the mean PASI score from 19·84 to 7·35 after 12 months (63% improvement). CONCLUSIONS: This is the first field study analysing the use of Fumaderm and the improvement of quality of life in patients with psoriasis under daily outpatient conditions. The improvement of DLQI obtained with Fumaderm was comparable with the improvement observed in patients with psoriasis treated with modern biologics. Importantly, in most patients with good clinical response, the treatment dose was one to three tablets daily.


Asunto(s)
Fármacos Dermatológicos/administración & dosificación , Fumaratos/administración & dosificación , Psoriasis/tratamiento farmacológico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Dimetilfumarato , Relación Dosis-Respuesta a Droga , Sustitución de Medicamentos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Calidad de Vida , Comprimidos , Resultado del Tratamiento , Adulto Joven
18.
Ultrasound Obstet Gynecol ; 43(3): 322-7, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23754206

RESUMEN

OBJECTIVES: To evaluate the diagnostic accuracy of rectal endoscopic sonography (RES) in the prediction of the infiltration depth of rectal endometriosis and to ascertain whether RES could be used to choose between segmental bowel resection and a more conservative approach, such as shaving or discoid resection. METHODS: In this retrospective study, 38 consecutive patients with symptomatic deep infiltrating endometriosis of the rectum who underwent laparoscopic colorectal resection were included. RES results for infiltration depth of rectal endometriosis were compared with results of pathological examination. The sensitivity, specificity, positive and negative predictive values (PPV and NPV, respectively), positive and negative likelihood ratios (LRs) and test accuracy were calculated for the presence of infiltration of the muscularis layers and submucosal/mucosal layers, as demonstrated by RES and confirmed by histopathological analysis. RESULTS: For the detection of muscularis layer infiltration by endometriosis, the PPV of RES was 100%, whereas for the detection of submucosal/mucosal layer involvement, the sensitivity was 89%, specificity was 26%, PPV was 55%, NPV was 71%, test accuracy was 58% and positive and negative LRs were 1.21 and 0.40, respectively. CONCLUSIONS: RES is a valuable tool for detecting rectal endometriosis as endometriotic infiltration of the muscularis layer can be predicted accurately. However, RES is less accurate in detecting submucosal/mucosal layer involvement and cannot, therefore, be used to choose between bowel resection and a more conservative approach.


Asunto(s)
Endometriosis/diagnóstico por imagen , Endosonografía , Laparoscopía/métodos , Enfermedades del Recto/diagnóstico por imagen , Adulto , Endometriosis/patología , Endometriosis/cirugía , Femenino , Humanos , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Enfermedades del Recto/patología , Enfermedades del Recto/cirugía , Estudios Retrospectivos , Sensibilidad y Especificidad
19.
Cereb Cortex ; 23(8): 1784-97, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22710611

RESUMEN

Recently, it has been discovered that the working memory deficits induced by exposure to chronic stress can be prevented by treating stressed animals with minocycline, a putative inhibitor of microglial activity. One of the pressing issues that now requires clarification is exactly how exposure to chronic stress modifies microglial morphology, this being a significant issue as microglial morphology is tightly coupled with their function. To examine how chronic stress alters microglial morphology, we digitally reconstructed microglia within the rat medial prefrontal cortex. Our analysis revealed that stress increased the internal complexity of microglia, enhancing ramification (i.e. branching) without altering the overall area occupied by the cell and that this effect was more pronounced in larger cells. We subsequently determined that minocycline treatment largely abolished the pro-ramifying effects of stress. With respect to mechanisms, we could not find any evidence of increased inflammation or neurodegeneration (interleukin-1ß, MHC-II, CD68, terminal deoxynucleotidyl transferase dUTP nick end labeling, and activated caspase-3). We did, however, find that chronic stress markedly increased the expression of ß1-integrin (CD29), a protein previously implicated in microglial ramification. Together, these findings highlight that increased ramification of microglia may represent an important neurobiological mechanism through which microglia mediate the behavioral effects of chronic psychological stress.


Asunto(s)
Microglía/citología , Minociclina/farmacología , Corteza Prefrontal/citología , Estrés Fisiológico/fisiología , Animales , Masculino , Microglía/efectos de los fármacos , Corteza Prefrontal/efectos de los fármacos , Ratas , Ratas Sprague-Dawley
20.
Biochemistry ; 52(45): 7910-25, 2013 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-24116947

RESUMEN

The Rhodnius nitrophorins are ß-barrel proteins of the lipocalin fold with a heme protruding from the open end of the barrel. They are found in the saliva of the blood-sucking insect Rhodnius prolixus, which synthesizes and stores nitric oxide (NO) in the salivary glands, where NO is bound to iron. NO is released by dilution and an increase in pH when the insect spits its saliva into the tissues of a victim, to aid in obtaining a blood meal. In the adult insect, there are four nitrophorins, NP1-NP4. At pH 7.3, NP4 releases NO 17 times faster than NP2 does, as measured by stopped-flow kinetics. A number of crystal structures of the least abundant protein, NP4, are available. These structures have been used to propose that two loops between adjacent ß-strands at the front opening of the protein, the A-B and G-H loops, determine the rate of NO release. To learn how the protein loops contribute to the release of NO for each of the nitrophorins, the dynamics of these proteins are being studied in our laboratory. In this work, the NP2-NO complex has been investigated by nuclear magnetic resonance relaxation measurements to probe the picosecond-to-nanosecond and microsecond-to-millisecond time scale motions at three pH values, 5.0, 6.5, and 7.3. It is found that at pH 5.0 and 6.5, the NP2-NO complex is rigid and only a few residues in the loop regions show dynamics, while at pH 7.3, somewhat more dynamics, particularly of the A-B loop, are observed. Comparison to other lipocalins shows that all are relatively rigid, and that the dynamics of lipocalins in general are much more subtle than those of mainly α-helical proteins.


Asunto(s)
Hemoproteínas/química , Hemoproteínas/metabolismo , Espectroscopía de Resonancia Magnética/métodos , Óxido Nítrico/química , Óxido Nítrico/metabolismo , Proteínas y Péptidos Salivales/química , Proteínas y Péptidos Salivales/metabolismo , Animales , Concentración de Iones de Hidrógeno , Unión Proteica
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