RESUMEN
A growing body of research is focused on identifying and understanding the neurophysiological mechanisms that underlie tinnitus. Unfortunately, however, most current models cannot adequately explain the majority of tinnitus features. For instance, although tinnitus generally appears within minutes after entering a silent environment, most models postulate that tinnitus emerges over a much larger timescale (days). Similarly, there is a limited understanding of how the severity of tinnitus can differ in patients with a similar degree of hearing loss. To address this critical knowledge gap, we have formulated a novel explanatory model of tinnitus, the perception-update (PU) model, which rests on a theory of information processing and can explain several key characteristics of tinnitus onset. The PU model posits that the brain continuously updates the information received from the inner ear by comparing it to the received information immediately before. That is, the auditory system processes the relative change in sensory input, as opposed to the absolute value of the auditory input. This is analogous to the functioning of data compression technology used for music and images called differential pulse code modulation (differential PCM). The PU model proposes that the inner ear transmits sound change to the auditory cortex via an auditory N1 response, an event-related potential component that constitutes is a prime signaler of auditory input change. In cases of hearing impairment, the PU model posits that the auditory system finds itself in a state of uncertainty where perception has to be predicted based on previous stimulation parameters, which can lead to the emergence of tinnitus.
RESUMEN
In vitro synthesis of (1 â 3)-ß-D-glucan was performed using laminaribiose phosphorylase obtained by an extraction of Euglena gracilis with sucrose phosphorylase. The synthetic product was a linear (1 â 3)-ß-D-glucan with a narrow distribution of degree of polymerization (DP) centered on DP=30. X-ray diffraction and electron microscopy revealed that the glucan molecules obtained were self-organized as highly crystalline hexagonal lamellae. This synthetic product has quite high structural homogeneity at every level from primary to higher-order structure, which is a great advantage for the detailed analyses of physiological functions of (1 â 3)-ß-D-glucan.
Asunto(s)
Euglena gracilis/química , Glucosiltransferasas/química , beta-Glucanos/síntesis química , Glucosiltransferasas/aislamiento & purificación , Microscopía Electrónica , Proteoglicanos , Difracción de Rayos XRESUMEN
The present case report details our experience with the hybrid approach for multiple aneurysms in the aortic arch, thoracoabdominal aorta, and around the aortic bifurcation. Total arch replacement for the arch aneurysm under hypothermic cardiopulmonary bypass with antegrade cerebral perfusion was the first stage of aneurysm repair. Five months later, bifurcated graft replacement with debranching of four abdominal branches was undertaken as the second stage of treatment. Finally, stent-graft repair for chronic dissection of the thoracoabdominal aorta was performed utilizing a Gore-Tex Tag endovascular prosthesis. Over 7 months of treatment, all aneurysms were excluded from the aortic blood flow and pressure without abdominal organ dysfunction except a transiently elevated total bilirubin level. Although the patient had an episode of minor gastrointestinal bleeding after discharge, he is currently leading a normal life without limitations at home 5 months after the stent-graft repair.
Asunto(s)
Aneurisma de la Aorta Abdominal/cirugía , Aneurisma de la Aorta Torácica/cirugía , Disección Aórtica/cirugía , Implantación de Prótesis Vascular , Procedimientos Endovasculares , Anciano , Disección Aórtica/diagnóstico por imagen , Aneurisma de la Aorta Abdominal/diagnóstico por imagen , Aneurisma de la Aorta Torácica/diagnóstico por imagen , Aortografía/métodos , Prótesis Vascular , Implantación de Prótesis Vascular/efectos adversos , Implantación de Prótesis Vascular/instrumentación , Procedimientos Endovasculares/efectos adversos , Procedimientos Endovasculares/instrumentación , Humanos , Masculino , Diseño de Prótesis , Stents , Tomografía Computarizada por Rayos X , Resultado del TratamientoRESUMEN
Abdominal aortic dissection (AAD) is a rare pathology and potentially causes rupture or other serious complications. This case report details our experience in endovascular aneurysm repair for AAD in a patient who had a history of coronary bypass surgery. Circumferential dissection of terminal aorta showed stenosis of true lumen as well as blood flow present in the pseudolumen. Using Zenith AAA endovascular device, the entry site was closed and the pseudolumen was thrombosed successfully. In the present report, published data on AAD were reviewed and endovascular aneurysm repair as a treatment option has been discussed as well.
Asunto(s)
Aneurisma de la Aorta Abdominal/cirugía , Disección Aórtica/cirugía , Implantación de Prótesis Vascular , Procedimientos Endovasculares , Disección Aórtica/diagnóstico por imagen , Disección Aórtica/fisiopatología , Aneurisma de la Aorta Abdominal/diagnóstico por imagen , Aneurisma de la Aorta Abdominal/fisiopatología , Aortografía/métodos , Prótesis Vascular , Implantación de Prótesis Vascular/instrumentación , Puente de Arteria Coronaria , Procedimientos Endovasculares/instrumentación , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Diseño de Prótesis , Stents , Tomografía Computarizada por Rayos X , Resultado del TratamientoRESUMEN
Aluminum (Al) resistance in wheat relies on the Al-activated malate efflux from root apices, which appears to be controlled by an Al-activated anion transporter encoded by the ALMT1 gene on chromosome 4DL. Genomic regions upstream and downstream of ALMT1 in 69 wheat lines were characterized to identify patterns that might influence ALMT1 expression. The first 1,000 bp downstream of ALMT1 was conserved among the lines examined apart from the presence of a transposon-like sequence which did not correlate with Al resistance. In contrast, the first 1,000 bp upstream of the ALMT1 coding region was more variable and six different patterns could be discerned (types I-VI). Type I had the simplest structure, while the others had blocks of sequence that were duplicated or triplicated in different arrangements. A pattern emerged among the lines of non-Japanese origin such that the number of repeats in this upstream region was positively correlated with the levels of ALMT1 expression and Al resistance. In contrast, many of the Japanese lines exhibited a large variation in ALMT1 expression and Al resistance despite possessing the same type of upstream region. Although ALMT1 expression was also poorly correlated with Al-activated malate efflux in the Japanese lines, a strong correlation between malate efflux and Al resistance suggested that malate efflux was still the primary mechanism for Al resistance, and that additional genes are involved in the post-transcriptional regulation of ALMT1 function.
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Aluminio/metabolismo , Transportadores de Anión Orgánico/genética , Triticum/genética , Secuencia de Bases , Regulación de la Expresión Génica de las Plantas , Malatos/metabolismo , Datos de Secuencia Molecular , Transportadores de Anión Orgánico/metabolismo , Triticum/metabolismoRESUMEN
Upon laser irradiation in air, metallic single-walled carbon nanotubes (SWNTs) in carbon nanotube thin film can be destroyed in preference to their semiconducting counterparts when the wavelength and power intensity of the irradiation are appropriate and the carbon nanotubes are not heavily bundled. Our method takes advantage of these two species' different rates of photolysis-assisted oxidation, creating the possibility of defining the semiconducting portions of carbon nanotube (CNT) networks using optical lithography, particularly when constructing all-CNT FETs (without metal electrodes) in the future.
RESUMEN
While it is well-known that tube-tube interaction causes changes (peak red-shift and suppression) in the optical absorption of single-walled carbon nanotubes (SWNTs), we found in this work that, upon bundling, the optical absorption of metallic SWNTs (M11) is less affected compared to their semiconducting counterparts (S11 or S22), resulting in enhanced absorbance ratio of metallic and semiconducting SWNTs (A(M)/A(S)). Annealing of the SWNTs increases this ratio due to the intensified tube-tube interaction. We have also found that the interaction between SWNTs and the surfactant Triton X-405 has a similar effect. The evaluation of SWNT separation by types (metallic or semiconducting) based on the optical absorption should take these effects into account.
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We compared neural activation detected by magnetoencephalography (MEG) during tactile presentation of words and non-words in a postlingually deaf-blind subject and six normal volunteers. The left postcentral gyrus, bilateral inferior frontal gyri, left posterior temporal lobe, right anterior temporal lobe, bilateral middle occipital gyri were activated when tactile words were presented to the right hand of the deaf-blind subject. This set of activated regions was not observed in the normal volunteers, although activation of several combinations of these regions was detected. Positron emission tomography confirmed the location of the MEG-activated areas in the deaf-blind subject. Our results demonstrated that the deaf-blind subject is heavily involved in interpreting tactile language by enhancing cortical activation of cognitive and semantic processing.
Asunto(s)
Ceguera/fisiopatología , Corteza Cerebral/fisiopatología , Sordera/fisiopatología , Comunicación Manual , Tacto/fisiología , Conducta Verbal/fisiología , Adulto , Ceguera/diagnóstico por imagen , Mapeo Encefálico , Corteza Cerebral/anatomía & histología , Corteza Cerebral/diagnóstico por imagen , Cognición/fisiología , Sordera/diagnóstico por imagen , Lateralidad Funcional/fisiología , Humanos , Imaginación/fisiología , Lenguaje , Pruebas del Lenguaje , Magnetoencefalografía , Masculino , Plasticidad Neuronal/fisiología , Valores de Referencia , Semántica , Tomografía Computarizada de EmisiónRESUMEN
CD100/Sema4D belongs to the semaphorin family, factors known to act as repulsive cues for axons during neuronal development. Mouse CD100 plays a crucial role in both humoral and cellular immunity through ligation of the lymphocyte receptor, CD72. It remains controversial, however, whether human CD100 can function through human CD72 in a manner similar to mouse CD100. To determine the function of human CD100, we generated a recombinant soluble human CD100 protein comprised of the extracellular region of human CD100 fused to the human IgG1 Fc region (hCD100-Fc). hCD100-Fc specifically binds to cells expressing human CD72. As observed previously in the mouse, hCD100-Fc induces the tyrosine dephosphorylation of human CD72, leading to the dissociation of SHP-1 from the CD72 cytoplasmic tail. Consistent with findings for mouse CD100, hCD100-Fc exerts a co-stimulatory effect on B cells and dendritic cells that are stimulated with anti-CD40 mAb. Furthermore, both hCD100-Fc and anti-human CD72 agonistic mAb induce the production of the pro-inflammatory cytokines tumor necrosis factor-alpha, IL-6 and IL-8, even in the absence of anti-CD40 mAb. Collectively, our findings not only demonstrate that human CD100, interacting with human CD72, can function as a ligand in a manner similar to mouse CD100, but also suggest the involvement of human CD100 in inflammatory responses.
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Antígenos CD/fisiología , Antígenos de Diferenciación de Linfocitos B/fisiología , Sistema Inmunológico/fisiología , Inflamación/fisiopatología , Glicoproteínas de Membrana/fisiología , Proteínas del Tejido Nervioso , Receptores de Superficie Celular , Semaforinas , Animales , Antígenos CD/genética , Antígenos CD/inmunología , Antígenos de Diferenciación de Linfocitos B/genética , Antígenos de Diferenciación de Linfocitos B/inmunología , Linfocitos B/inmunología , Antígenos CD40/inmunología , Células CHO , Células COS , División Celular/fisiología , Chlorocebus aethiops , Clonación Molecular , Cricetinae , Células Dendríticas/metabolismo , Citometría de Flujo , Regulación de la Expresión Génica , Humanos , Interleucina-12/análisis , Interleucina-12/metabolismo , Interleucina-6/análisis , Interleucina-6/metabolismo , Interleucina-8/análisis , Interleucina-8/metabolismo , Péptidos y Proteínas de Señalización Intracelular , Activación de Linfocitos/inmunología , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/inmunología , Monocitos/metabolismo , Tonsila Palatina/citología , Unión Proteica , Proteína Tirosina Fosfatasa no Receptora Tipo 6 , Proteínas Tirosina Fosfatasas/metabolismo , Proteínas Recombinantes de Fusión/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transfección , Factor de Necrosis Tumoral alfa/análisis , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
We used the rats in which one olfactory nerve had been transected and observed the odor (Propionic acid) -induced c-Fos immunoreactivity in the bulb at different times (2, 4, 8 weeks) after nerve transection. The exposure to odor produced a strong cluster of c-Fos positive cells in the mediodorsal region of the intact bulb. On the other hand, the transected bulb showed much less reactivity 2 weeks after neurectomy; however, a large number of positive cells were observed in the whole of the bulb from 4 weeks after neurectomy. Furthermore, we measured the levels of mRNA for tyrosine hydroxylase (TH), which was the marker of odor-induced olfactory nerve activity in the bulb, by using real-time PCR. The level of TH mRNA decreased on the transected side at 2 weeks but recovered to the level of the contralateral side at 4 weeks after neurectomy. We firstly demonstrated that projection mapping of odor receptors was altered after olfactory nerve transection by using an immunohistochemical method.
Asunto(s)
Bulbo Olfatorio/metabolismo , Neuronas Receptoras Olfatorias/metabolismo , Proteínas Proto-Oncogénicas c-fos/metabolismo , Animales , Axotomía , Inmunohistoquímica , Masculino , Odorantes , Bulbo Olfatorio/efectos de los fármacos , Nervio Olfatorio/fisiología , Vías Olfatorias/metabolismo , Neuronas Receptoras Olfatorias/efectos de los fármacos , Reacción en Cadena de la Polimerasa , Propionatos/farmacología , Proteínas Proto-Oncogénicas c-fos/efectos de los fármacos , ARN Mensajero/análisis , Ratas , Ratas Wistar , Factores de Tiempo , Tirosina 3-Monooxigenasa/metabolismoRESUMEN
We developed a new ultrasonographic imaging technique to be used in a water-filled nasal cavity during endoscopic sinus surgery, and estimated how well surgically dangerous sites were depicted. Our newly developed balloon can completely fill the choana, preventing water from leaking into the pharynx. The balloon enables endoscopic sinus surgery to be relatively safely performed in "flowing water." Fifteen patients with chronic sinusitis underwent endoscopic sinus surgery under local anesthesia, and a MicroTip Radial probe was inserted into the water-filled nasal cavity. The orbital contents, skull base, and maxillary sinuses were visualized in all cases. Even in cases with a thin lamina papyracea, the boundary of the orbit could be judged from the motion of the orbital contents. Ultrasound information obtained in real time will be useful for improving the safety of endoscopic sinus surgery. Our ultrasonographic imaging technique can provide an early warning to the surgeon and thereby prevent severe complications.
Asunto(s)
Endoscopía , Cavidad Nasal/diagnóstico por imagen , Senos Paranasales/cirugía , Sinusitis/cirugía , Agua , Humanos , UltrasonografíaRESUMEN
As a way of alleviating severe constipation in cancer patients taking morphine to relieve pain, effects of Dai-kenchu-to (DKT), a traditional Japanese herbal medicine (Kampo medicine), on gastrointestinal transit in mice or on the isolated guinea pig ileum were studied in special reference to morphine. Without altering the anti-nociceptive effect of morphine, DKT was significantly effective against morphine-induced disorder of gastrointestinal transit in mice as assessed by the charcoal meal test for the intestine and measurement of transit time for the colon tract. The results of in vitro studies with guinea pig ileum suggest that abatement of morphine-induced disorder of transit by DKT is caused by both moderate contraction of morphine-treated longitudinal muscle and relaxation of morphine-induced tonic contraction of circular muscle.