Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 34
Filtrar
1.
In Vivo ; 36(5): 2211-2217, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36099114

RESUMO

BACKGROUND/AIM: Acid-electrolyzed functional water (FW) is an efficient bactericide and gargling with FW might be an effective method of oral care. We investigated the possible use of FW as a mouth wash by an in vitro study. MATERIALS AND METHODS: The bactericidal effect of FW against different species of bacteria (Staphylococcus aureus, Streptococcus pneumonia, Pseudomonas aeruginosa, and Candida albicans) was evaluated using the numbers of colony-forming units (CFU). The experiment was conducted using PBS, LISTERINE, and ConCool F (undiluted, and the optimal concentration indicated). To investigate the bactericidal mechanism of FW, the activity of superoxide dismutase (SOD), an indicator of oxidative action, was measured in S. aureus. FW was diluted with purified water to concentrations of 10, 30, 50, and 70%. The numbers of CFU were measured for each concentration. XTT assays were performed using HSC-3 and HeLa cells, to examine the viability of the cells following treatment with FW. The same experiment was conducted with PBS, LISTERINE, and undiluted ConCool F. RESULTS: No bacteria treated with FW formed colonies. SOD activity peaked at a 50% concentration of FW and was more than twice that of the control. A significant decrease in the number of CFU was observed following 50% treatment. Since the peaks of the SOD activity and the starting concentrations of the bactericidal effects coincided, the bactericidal effect of FW might be related to its oxidative effects. Bacteria treated with FW had the same survival rate as the other mouth washes. CONCLUSION: FW might be clinically applicable as a mouth wash.


Assuntos
Antissépticos Bucais , Água , Antibacterianos/farmacologia , Bactérias , Células HeLa , Humanos , Antissépticos Bucais/farmacologia , Staphylococcus aureus , Superóxido Dismutase/farmacologia , Água/farmacologia
2.
Clin Hemorheol Microcirc ; 82(1): 1-12, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35599472

RESUMO

BACKGROUND: Exercise-induced impairment of blood fluidity is considered to be associated with thrombosis development. However, the effects of L-arginine on blood fluidity after exercise remain unclear. OBJECTIVE: We investigated the mechanisms of impaired blood fluidity after high-intensity exercise, and examined whether L-arginine improves exercise-induced blood fluidity impairment in vitro. METHODS: Ten healthy male participants performed 15 minutes of ergometer exercise at 70% of their peak oxygen uptake levels. Blood samples were obtained before and after exercise. L-arginine and NG-monomethyl-L-arginine acetate (L-NMMA)-a nitric oxide (NO) synthase inhibitor-were added to the post-exercise blood samples. Using Kikuchi's microchannel method, we measured the blood passage time, percentage of obstructed microchannels, and the number of adherent white blood cells (WBCs) on the microchannel terrace. RESULTS: Exercise increased the hematocrit levels. The blood passage times, percentage of obstructed microchannels, and the number of adherent WBCs on the microchannel terrace increased after exercise; however, they decreased in a dose-dependent manner after the addition of L-arginine. L-NMMA inhibited the L-arginine-induced decrease in blood passage time. CONCLUSIONS: High-intensity exercise impairs blood fluidity by inducing hemoconcentration along with increasing platelet aggregation and WBC adhesion. The L-arginine-NO pathway improves blood fluidity impairment after high-intensity exercise in vitro.


Assuntos
Arginina , Óxido Nítrico , Humanos , Masculino , ômega-N-Metilarginina/farmacologia , Arginina/farmacologia , Exercício Físico , Leucócitos , Agregação Plaquetária
3.
In Vivo ; 36(2): 979-984, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35241559

RESUMO

BACKGROUND/AIM: Surgery remains the standard treatment for salivary gland carcinoma (SGC). Our study investigated the association between epidermal growth factor receptor (EGFR) status in recurrent/metastatic SGC and the effectiveness of treatment with cisplatin/carboplatin and 5-fluorouracil plus cetuximab (EXTREME). PATIENTS AND METHODS: We retrospectively collected 19 SGCs from patients treated with the EXTREME regimen. After analyzing EGFR expression and gene copy number gain, we evaluated the correlation between EGFR status and clinicopathological factors and prognosis. RESULTS: EGFR overexpression was detected in 77.8% cases, but not statistically associated with clinicopathological factors or prognosis. EGFR gene copy number gain was detected in 16.7% cases, and statistically positively correlated with lymph node metastasis (p=0.0291). The best overall response was partial response in two cases, stable disease in 15, and progressive disease in one case. The EXTREME regimen was discontinued in all cases. CONCLUSION: Our results suggest that SGCs are positive for EGFR protein expression but the response rate to the EXTREME regimen was unremarkable.


Assuntos
Cisplatino , Neoplasias das Glândulas Salivares , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Carboplatina/efeitos adversos , Cetuximab/efeitos adversos , Cisplatino/uso terapêutico , Fluoruracila , Humanos , Recidiva Local de Neoplasia/patologia , Estudos Retrospectivos
4.
Anticancer Res ; 42(2): 981-989, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35093898

RESUMO

BACKGROUND/AIM: The efficacy of programmed cell death 1 (PD-1) inhibitor therapy for patients with recurrent and/or metastatic salivary gland carcinoma (R/M SGC) remains unclear. PATIENTS AND METHODS: We retrospectively analyzed 36 patients with R/M SGC treated with PD-1 inhibitor. The expression of programmed cell death ligand 1 (PD-L1) and mismatch repair (MMR) proteins was also analyzed. RESULTS: The objective response rate (ORR) was 11.1%. The histopathological subtypes of patients who achieved complete response or partial response were salivary duct carcinoma (SDC) in three patients and poorly differentiated carcinoma in one patient, all of whom showed a positive PD-L1 expression. The expression of MMR proteins was not associated with the efficacy of PD-1 inhibitors. CONCLUSION: Although the efficacy of PD-1 inhibitor therapy in R/M SGC is limited, certain patients may respond and achieve long-term disease control. There is a potential therapeutic effect in SDC patients with positive PD-L1 expression.


Assuntos
Carcinoma/tratamento farmacológico , Inibidores de Checkpoint Imunológico/uso terapêutico , Neoplasias das Glândulas Salivares/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígeno B7-H1/metabolismo , Carcinoma/metabolismo , Carcinoma/mortalidade , Carcinoma/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Neoplasias das Glândulas Salivares/metabolismo , Neoplasias das Glândulas Salivares/mortalidade , Neoplasias das Glândulas Salivares/patologia , Análise de Sobrevida , Resultado do Tratamento
5.
Auris Nasus Larynx ; 49(3): 484-494, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34772563

RESUMO

OBJECTIVE: Concave deformities and gustatory sweating are the most common complications that cause substantial patient dissatisfaction after parotidectomy. Various surgical methods to prevent these complications have been described. However, effective techniques have not been established, especially in patients with medium- to large-sized parotidectomy defects. We evaluated the utility of infrahyoid myofascial flap reconstruction of parotidectomy defects for the prevention of these complications. METHODS: We conducted a retrospective case series study in patients with a benign or malignant parotid tumor measuring over 4 cm who underwent immediate pedicle infrahyoid myofascial flap reconstruction after total or subtotal parotidectomy or total resection of either the superficial or deep parotid gland at our hospital. Subjective analyses of facial symmetry, postoperative concave deformities of the anterior neck, gustatory sweating, voice disorders, odynophagia, neck scarring in the parotid and anterior neck areas, sensory disorders, pain, and neck stiffness were performed using patient interview data. Objective evaluations of facial symmetry were made by the first or second author. Both analyses were performed after a follow-up of more than six months. Additionally, patient demographic data, clinicopathological factors, parotidectomy and skin incision types, flap survival, and postoperative complications were evaluated. RESULTS: We included eight patients (male, n=5; mean age, 69.3 years [range, 37-93 years]). Procedures included total or subtotal parotidectomy (n=4), superficial lobe parotidectomy (n=2), and deep lobe parotidectomy with partial superficial lobe parotidectomy (n=2). Infrahyoid myofascial flaps reached the cranial tip of the parotid defect without tension, and their volume sufficiently filled the parotidectomy defect in all patients. There were no local signs of insufficient blood flow within the transferred flaps. Objective and subjective assessments were made after a mean duration of 1.2 years (range, 0.6-1.8). Postoperatively, no patient subjectively reported facial asymmetry. Objectively, facial symmetry was "good" in four patients and "fair" in four patients. No distinctly visible concave deformity in the parotid or anterior neck area occurred in any patient. Gustatory sweating occurred in one patient; this individual had the largest parotidectomy defect. Only one patient experienced donor site morbidity (mild anterior neck stiffness) related to infrahyoid myofascial flap elevation. CONCLUSION: Although complete prevention of gustatory sweating was unsuccessful, infrahyoid myofascial flap reconstruction of medium- to large-sized parotidectomy defects led to postoperative facial symmetry with minimal donor site morbidity.


Assuntos
Neoplasias Parotídeas , Sudorese Gustativa , Idoso , Humanos , Masculino , Glândula Parótida/cirurgia , Neoplasias Parotídeas/complicações , Neoplasias Parotídeas/cirurgia , Complicações Pós-Operatórias/prevenção & controle , Estudos Retrospectivos , Retalhos Cirúrgicos , Sudorese Gustativa/prevenção & controle
6.
Cell Rep ; 37(6): 109966, 2021 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-34758322

RESUMO

Sensory processing is essential for motor control. Climbing fibers from the inferior olive transmit sensory signals to Purkinje cells, but how the signals are represented in the cerebellar cortex remains elusive. To examine the olivocerebellar organization of the mouse brain, we perform quantitative Ca2+ imaging to measure complex spikes (CSs) evoked by climbing fiber inputs over the entire dorsal surface of the cerebellum simultaneously. The surface is divided into approximately 200 segments, each composed of ∼100 Purkinje cells that fire CSs synchronously. Our in vivo imaging reveals that, although stimulation of four limb muscles individually elicits similar global CS responses across nearly all segments, the timing and location of a stimulus are derived by Bayesian inference from coordinated activation and inactivation of multiple segments on a single trial basis. We propose that the cerebellum performs segment-based, distributed-population coding that represents the conditional probability of sensory events.


Assuntos
Potenciais de Ação , Cálcio/metabolismo , Cerebelo/fisiologia , Rede Nervosa/fisiologia , Núcleo Olivar/fisiologia , Células de Purkinje/fisiologia , Órgãos dos Sentidos/fisiologia , Animais , Teorema de Bayes , Cerebelo/citologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos ICR , Rede Nervosa/citologia , Núcleo Olivar/citologia , Células de Purkinje/citologia , Órgãos dos Sentidos/citologia
8.
J Physiol ; 599(19): 4497-4516, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34426971

RESUMO

Excitable cochlear hair cells convert the mechanical energy of sounds into the electrical signals necessary for neurotransmission. The key process is cellular depolarization via K+ entry from K+ -enriched endolymph through hair cells' mechanosensitive channels. Positive 80 mV potential in endolymph accelerates the K+ entry, thereby sensitizing hearing. This potential represents positive extracellular potential within the epithelial-like stria vascularis; the latter potential stems from K+ equilibrium potential (EK ) across the strial membrane. Extra- and intracellular [K+ ] determining EK are likely maintained by continuous unidirectional circulation of K+ through a putative K+ transport pathway containing hair cells and stria. Whether and how the non-excitable tissue stria vascularis responds to acoustic stimuli remains unclear. Therefore, we analysed a cochlear portion for the best frequency, 1 kHz, by theoretical and experimental approaches. We have previously developed a computational model that integrates ion channels and transporters in the stria and hair cells into a circuit and described a circulation current composed of K+ . Here, in this model, mimicking of hair cells' K+ flow induced by a 1 kHz sound modulated the circulation current and affected the strial ion transport mechanisms; the latter effect resulted in monotonically decreasing potential and increasing [K+ ] in the extracellular strial compartment. Similar results were obtained when the stria in acoustically stimulated animals was examined using microelectrodes detecting the potential and [K+ ]. Measured potential dynamics mirrored the EK change. Collectively, because stria vascularis is electrically coupled to hair cells by the circulation current in vivo too, the strial electrochemical properties respond to sounds. KEY POINTS: A highly positive potential of +80 mV in K+ -enriched endolymph in the mammalian cochlea accelerates sound-induced K+ entry into excitable sensory hair cells, a process that triggers hearing. This unique endolymphatic potential represents an EK -based battery for a non-excitable epithelial-like tissue, the stria vascularis. To examine whether and how the stria vascularis responds to sounds, we used our computational model, in which strial channels and transporters are serially connected to those hair cells in a closed-loop circuit, and found that mimicking hair cell excitation by acoustic stimuli resulted in increased extracellular [K+ ] and decreased the battery's potential within the stria. This observation was overall verified by electrophysiological experiments using live guinea pigs. The sensitivity of electrochemical properties of the stria to sounds indicates that this tissue is electrically coupled to hair cells by a radial ionic flow called a circulation current.


Assuntos
Potássio , Estria Vascular , Animais , Cóclea , Endolinfa , Cobaias , Células Ciliadas Auditivas
9.
J Neurosci Methods ; 351: 109074, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33450333

RESUMO

BACKGROUND: Essential tremor is the most prevalent movement disorder and is thought to be caused by abnormalities in the cerebellar system; however, its underlying neural mechanism is poorly understood. In this study, we found that mice lacking netrin-G2, a cell adhesion molecule which is expressed in neural circuits related to the cerebellar system, exhibited a microtremor resembling an essential tremor. However, it was difficult to quantify microtremors in netrin-G2 KO mice. NEW METHOD: We developed a new tremor detector which can quantify the intensity and frequency of a tremor. RESULTS: Using this system, we were able to characterize both the microtremors in netrin-G2 KO mice and low-dose harmaline-induced tremors which, to date, had been difficult to detect. Alcohol and anti-tremor drugs, which are effective in decreasing the symptoms of essential tremor in patients, were examined in netrin-G2 KO mice. We found that some drugs lowered the tremor frequency, but had little effect on tremor intensity. Forced swim as a stress stimulus in netrin-G2 KO mice dramatically enhanced tremor symptoms. COMPARISON WITH EXISTING METHODS: The detection performance even for tremors induced by low-dose harmaline was similar to that in previous studies or more sensitive than the others. CONCLUSIONS: Microtremors in netrin-G2 KO mice are reliably and quantitatively detected by our new tremor detection system. We found different effects of medicines and factors between human essential tremors and microtremors in netrin-G2 KO mice, suggesting that the causations, mechanisms, and symptoms of tremors vary and are heterogeneous, and the objective analyses are required.


Assuntos
Tremor Essencial , Harmalina , Animais , Humanos , Camundongos , Camundongos Knockout , Netrinas , Tremor
10.
J Int Adv Otol ; 14(3): 447-450, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30411705

RESUMO

OBJECTIVES: To evaluate the effects of chronic kidney disease (CKD) and hemodialysis (HD) on the inner ear using the G width (the width between the bimodal peaks of the conductance (G) tympanogram at 2,000 Hz), which reflects the inner ear pressure and/or the existence of endolymphatic hydrops. MATERIALS AND METHODS: We selected five patients (10 ears) from the patients with CKD who were hospitalized for creation of arteriovenous fistula prior to initiation of HD (non-HD group), and we selected seven patients (14 ears) from the patients with CKD who were undergoing HD (the HD group). As a control group, we selected 80 healthy individuals (160 ears); these were mainly the medical staff of the hospital. We measured the G width of the control group and that of patients with CKD using multifrequency tympanometry. RESULTS: The mean G widths of the HD (measured just before an HD session), non-HD, and control groups were 210.7, 128.4, and 97.0 daPa, respectively. The G width of the HD group was significantly greater than that of the control and non-HD groups (p<0.01 and p<0.01, respectively; Tukey-Kramer test after one-way analysis of variance). The non-HD group also had a greater G width than the control, but it was not significant (p=0.20; Tukey-Kramer). No significant changes were observed in the G widths of the HD group, just before and after a single HD session (p=0.423; paired t-test). CONCLUSION: The greater G width observed in hemodialyzed CKD patients suggests either an increased inner ear pressure or the existence of endolymphatic hydrops in these patients, which is probably related to their otologic symptoms.


Assuntos
Testes de Impedância Acústica/métodos , Orelha Interna/fisiopatologia , Diálise Renal/efeitos adversos , Insuficiência Renal Crônica/fisiopatologia , Idoso , Hidropisia Endolinfática/diagnóstico , Hidropisia Endolinfática/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pressão , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/terapia
11.
Cell Rep ; 22(11): 2873-2885, 2018 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-29539417

RESUMO

Multisensory integration (MSI) is a fundamental emergent property of the mammalian brain. During MSI, perceptual information encoded in patterned activity is processed in multimodal association cortex. The systems-level neuronal dynamics that coordinate MSI, however, are unknown. Here, we demonstrate intrinsic hub-like network activity in the association cortex that regulates MSI. We engineered calcium reporter mouse lines based on the fluorescence resonance energy transfer sensor yellow cameleon (YC2.60) expressed in excitatory or inhibitory neurons. In medial and parietal association cortex, we observed spontaneous slow waves that self-organized into hubs defined by long-range excitatory and local inhibitory circuits. Unlike directional source/sink-like flows in sensory areas, medial/parietal excitatory and inhibitory hubs had net-zero balanced inputs. Remarkably, multisensory stimulation triggered rapid phase-locking mainly of excitatory hub activity persisting for seconds after the stimulus offset. Therefore, association cortex tends to form balanced excitatory networks that configure slow-wave phase-locking for MSI. VIDEO ABSTRACT.


Assuntos
Córtex Cerebral/fisiologia , Neurônios/fisiologia , Animais , Córtex Cerebral/citologia , Camundongos
12.
Auris Nasus Larynx ; 45(1): 81-87, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28602229

RESUMO

OBJECTIVE: This study aimed to verify cutoff values for G width (the width of bimodal peaks for the waveform obtained when measuring conductance at 2000Hz) in Japanese individuals diagnosed with Ménière's disease (MD) using multifrequency tympanometry (MFT) and to determine the relationship between the G width and ability to hear low-pitched sounds using measurements over time. METHODS: The study included 51 patients with clinically diagnosed MD, who had not undergone endolymphatic sac surgery, but had no other known ear disease (57 ears in patients aged 22-80 years were affected, and 45 ears in patients aged 18-83 years were unaffected; mean age: 53.3±16.9 years). We also enlisted 80 healthy controls with no prior history of ear disease (160 ears, aged 22-76 years, mean age: 40.8±15.7 years). MFT was used to measure the bimodal peak width of the waveform obtained when measuring conductance at resonance frequency of 2000Hz. For patients who had G width measured several times over multiple outpatient visits, we used initial test data to analyze cutoff values. In nine cases with four or more measurements over time, we evaluated a possible correlation between G width and the sum of the hearing threshold for three low-pitched frequencies (125Hz, 250Hz, and 500Hz). We used Student's t-test to determine significance. RESULTS: The both ears in the MD patients had a G width wider than the distribution in the control group. There was a significant difference between G width in the control group and in affected ears with MD (p=0.00026) and there was also a significant difference between G width in the control group and in unaffected ears of MD patients (p=0.0056). The cutoff value set with a specificity of 95% was 200daPa, with a sensitivity of 35.1% and specificity of 95.6%. The cutoff value set with a sensitivity of 50% was 140daPa, with sensitivity of 50.9% and specificity of 78.8%. There was no significant difference between resonance frequency of ears in the control group and ears with MD (p=0.41). In nine cases with four or more measurements over time, a case showed a statistically significant positive correlation between the G width and hearing ability threshold for low-pitched sounds (125Hz, 250Hz, and 500Hz) (p=0.03), while an another case showed a tendency toward a positive correlation, which was not statistically significant (p=0.08). Further, there were cases that did not show significant differences in the present study, but might have shown a negative correlation if the number of measurements had been increased. CONCLUSION: Measurement of G width using MFT may have accuracy as the traditional endolymphatic hydrops test. MFT is non-invasive, causes little discomfort for patients, requires little time to perform, and can be performed by paramedics. MFT was shown to be useful in screening for MD and it is effective in diagnosing MD to measure the change over time of G width using MFT.


Assuntos
Testes de Impedância Acústica , Doença de Meniere/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Limiar Auditivo , Estudos de Casos e Controles , Orelha/fisiologia , Feminino , Humanos , Masculino , Doença de Meniere/fisiopatologia , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Adulto Jovem
13.
Front Mol Neurosci ; 10: 300, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29018325

RESUMO

Light-gated ion channels and transporters have been applied to a broad array of excitable cells including neurons, cardiac myocytes, skeletal muscle cells and pancreatic ß-cells in an organism to clarify their physiological and pathological roles. Nonetheless, among nonexcitable cells, only glial cells have been studied in vivo by this approach. Here, by optogenetic stimulation of a different nonexcitable cell type in the cochlea of the inner ear, we induce and control hearing loss. To our knowledge, deafness animal models using optogenetics have not yet been established. Analysis of transgenic mice expressing channelrhodopsin-2 (ChR2) induced by an oligodendrocyte-specific promoter identified this channel in nonglial cells-melanocytes-of an epithelial-like tissue in the cochlea. The membrane potential of these cells underlies a highly positive potential in a K+-rich extracellular solution, endolymph; this electrical property is essential for hearing. Illumination of the cochlea to activate ChR2 and depolarize the melanocytes significantly impaired hearing within a few minutes, accompanied by a reduction in the endolymphatic potential. After cessation of the illumination, the hearing thresholds and potential returned to baseline during several minutes. These responses were replicable multiple times. ChR2 was also expressed in cochlear glial cells surrounding the neuronal components, but slight neural activation caused by the optical stimulation was unlikely to be involved in the hearing impairment. The acute-onset, reversible and repeatable phenotype, which is inaccessible to conventional gene-targeting and pharmacological approaches, seems to at least partially resemble the symptom in a population of patients with sensorineural hearing loss. Taken together, this mouse line may not only broaden applications of optogenetics but also contribute to the progress of translational research on deafness.

14.
NPJ Syst Biol Appl ; 3: 24, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28861279

RESUMO

The cochlear lateral wall-an epithelial-like tissue comprising inner and outer layers-maintains +80 mV in endolymph. This endocochlear potential supports hearing and represents the sum of all membrane potentials across apical and basolateral surfaces of both layers. The apical surfaces are governed by K+ equilibrium potentials. Underlying extracellular and intracellular [K+] is likely controlled by the "circulation current," which crosses the two layers and unidirectionally flows throughout the cochlea. This idea was conceptually reinforced by our computational model integrating ion channels and transporters; however, contribution of the outer layer's basolateral surface remains unclear. Recent experiments showed that this basolateral surface transports K+ using Na+, K+-ATPases and an unusual characteristic of greater permeability to Na+ than to other ions. To determine whether and how these machineries are involved in the circulation current, we used an in silico approach. In our updated model, the outer layer's basolateral surface was provided with only Na+, K+-ATPases, Na+ conductance, and leak conductance. Under normal conditions, the circulation current was assumed to consist of K+ and be driven predominantly by Na+, K+-ATPases. The model replicated the experimentally measured electrochemical properties in all compartments of the lateral wall, and endocochlear potential, under normal conditions and during blocking of Na+, K+-ATPases. Therefore, the circulation current across the outer layer's basolateral surface depends primarily on the three ion transport mechanisms. During the blockage, the reduced circulation current partially consisted of transiently evoked Na+ flow via the two conductances. This work defines the comprehensive system driving the circulation current.

15.
Nat Biomed Eng ; 1(8): 654-666, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31015607

RESUMO

Real-time recording of the kinetics of systemically administered drugs in in vivo microenvironments may accelerate the development of effective medical therapies. However, conventional methods require considerable analyte quantities, have low sampling rates and do not address how drug kinetics correlate with target function over time. Here, we describe the development and application of a drug-sensing system consisting of a glass microelectrode and a microsensor composed of boron-doped diamond with a tip of around 40 µm in diameter. We show that, in the guinea pig cochlea, the system can measure-simultaneously and in real time-changes in the concentration of bumetanide (a diuretic that is ototoxic but applicable to epilepsy treatment) and the endocochlear potential underlying hearing. In the rat brain, we tracked the kinetics of the drug and the local field potentials representing neuronal activity. We also show that the actions of the antiepileptic drug lamotrigine and the anticancer reagent doxorubicin can be monitored in vivo. Our microsensing system offers the potential to detect pharmacological and physiological responses that might otherwise remain undetected.

16.
Pflugers Arch ; 468(10): 1637-49, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27568193

RESUMO

The cochlea of the mammalian inner ear contains an endolymph that exhibits an endocochlear potential (EP) of +80 mV with a [K(+)] of 150 mM. This unusual extracellular solution is maintained by the cochlear lateral wall, a double-layered epithelial-like tissue. Acoustic stimuli allow endolymphatic K(+) to enter sensory hair cells and excite them. The positive EP accelerates this K(+) influx, thereby sensitizing hearing. K(+) exits from hair cells and circulates back to the lateral wall, which unidirectionally transports K(+) to the endolymph. In vivo electrophysiological assays demonstrated that the EP stems primarily from two K(+) diffusion potentials yielded by [K(+)] gradients between intracellular and extracellular compartments in the lateral wall. Such gradients seem to be controlled by ion channels and transporters expressed in particular membrane domains of the two layers. Analyses of human deafness genes and genetically modified mice suggested the contribution of these channels and transporters to EP and hearing. A computational model, which reconstitutes unidirectional K(+) transport by incorporating channels and transporters in the lateral wall and connects this transport to hair cell transcellular K(+) fluxes, simulates the circulation current flowing between the endolymph and the perilymph. In this model, modulation of the circulation current profile accounts for the processes leading to EP loss under pathological conditions. This article not only summarizes the unique physiological and molecular mechanisms underlying homeostasis of the EP and their pathological relevance but also describes the interplay between EP and circulation current.


Assuntos
Potenciais de Ação , Cóclea/fisiologia , Surdez/fisiopatologia , Líquido Extracelular/metabolismo , Animais , Cóclea/metabolismo , Surdez/metabolismo , Homeostase , Humanos , Potássio/metabolismo
17.
Pflugers Arch ; 468(9): 1609-19, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27344659

RESUMO

Eukaryotic cells exhibit negative resting membrane potential (RMP) owing to the high K(+) permeability of the plasma membrane and the asymmetric [K(+)] between the extracellular and intracellular compartments. However, cochlear fibrocytes, which comprise the basolateral surface of a multilayer epithelial-like tissue, exhibit a RMP of +5 to +12 mV in vivo. This positive RMP is critical for the formation of an endocochlear potential (EP) of +80 mV in a K(+)-rich extracellular fluid, endolymph. The epithelial-like tissue bathes fibrocytes in a regular extracellular fluid, perilymph, and apically faces the endolymph. The EP, which is essential for hearing, represents the potential difference across the tissue. Using in vivo electrophysiological approaches, we describe a potential mechanism underlying the unusual RMP of guinea pig fibrocytes. The RMP was +9.0 ± 3.7 mV when fibrocytes were exposed to an artificial control perilymph (n = 28 cochleae). Perilymphatic perfusion of a solution containing low [Na(+)] (1 mM) markedly hyperpolarized the RMP to -31.1 ± 11.2 mV (n = 10; p < 0.0001 versus the control, Tukey-Kramer test after one-way ANOVA). Accordingly, the EP decreased. Little change in RMP was observed when the cells were treated with a high [K(+)] of 30 mM (+10.4 ± 2.3 mV; n = 7; p = 0.942 versus the control). During the infusion of a low [Cl(-)] solution (2.4 mM), the RMP moderately hyperpolarized to -0.9 ± 3.4 mV (n = 5; p < 0.01 versus the control), although the membranes, if governed by Cl(-) permeability, should be depolarized. These observations imply that the fibrocyte membranes are more permeable to Na(+) than K(+) and Cl(-), and this unique profile and [Na(+)] gradient across the membranes contribute to the positive RMP.


Assuntos
Permeabilidade da Membrana Celular , Cóclea/metabolismo , Potenciais da Membrana , Potássio/metabolismo , Sódio/metabolismo , Animais , Cloretos/metabolismo , Cóclea/citologia , Cóclea/fisiologia , Endolinfa/metabolismo , Cobaias , Transporte de Íons , Masculino , Perilinfa/metabolismo
18.
Auris Nasus Larynx ; 43(6): 666-71, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26965587

RESUMO

OBJECTIVE: Eyelid carcinomas are rare, and the management strategy of regional lymph node metastasis linked to eyelid carcinomas has not been standardized to date. The aim of the present study was to analyze the patterns of regional metastasis and to assess the optimal extent of surgical treatment for lymph node metastasis of eyelid carcinoma. METHODS: This study was a retrospective review of patient data from a single institution. From a series of 268 eyelid carcinomas, we selected the 21 patients with lymph node metastasis, and we analyzed the patterns of lymphatic spread, approach to treatment and outcomes. RESULTS: The most common histological type of eyelid carcinoma with regional metastasis was sebaceous carcinoma (17/21, 81.0%). Submandibular area metastases were seen only in the patients with the primary tumor originating in the medial half of the eyelid, but parotid area metastases were seen in both the patients whose tumors had a medial-half origin and those with a lateral-half origin. Although 11 of the 16 patients with parotid-area metastases underwent a tumorectomy or superficial parotidectomy (which resulted in four cases of recurrence in the parotid area), none of the five patients who underwent a total parotidectomy developed parotid-area recurrence. The incidence of regional recurrence of the patients who received adjuvant radiotherapy (14.3%) was lower than that of the patients without adjuvant radiotherapy (57.1%). CONCLUSION: Continued surveillance and optimal management of regional lymph node metastases are important for the control and survival of eyelid carcinomas.


Assuntos
Adenocarcinoma Sebáceo/patologia , Carcinoma Basocelular/patologia , Carcinoma de Célula de Merkel/patologia , Carcinoma de Células Escamosas/patologia , Neoplasias Palpebrais/patologia , Neoplasias de Cabeça e Pescoço/patologia , Linfonodos/patologia , Neoplasias das Glândulas Sebáceas/patologia , Adenocarcinoma Sebáceo/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Basocelular/terapia , Carcinoma de Célula de Merkel/terapia , Carcinoma de Células Escamosas/terapia , Neoplasias Palpebrais/terapia , Neoplasias de Cabeça e Pescoço/terapia , Humanos , Metástase Linfática , Pessoa de Meia-Idade , Pescoço , Exenteração Orbitária , Radioterapia Adjuvante , Estudos Retrospectivos , Neoplasias das Glândulas Sebáceas/terapia , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/terapia , Carcinoma de Células Escamosas de Cabeça e Pescoço , Procedimentos Cirúrgicos Operatórios
20.
Eur J Neurosci ; 42(3): 1984-2002, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26060893

RESUMO

Stria vascularis of the mammalian cochlea transports K(+) to establish the electrochemical property in the endolymph crucial for hearing. This epithelial tissue also transports various small molecules. To clarify the profile of proteins participating in the transport system in the stria vascularis, membrane components purified from the stria of adult rats were analysed by liquid chromatography tandem mass spectrometry. Of the 3236 proteins detected in the analysis, 1807 were membrane proteins. Ingenuity Knowledge Base and literature data identified 513 proteins as being expressed on the 'plasma membrane', these included 25 ion channels and 79 transporters. Sixteen of the former and 62 of the latter had not yet been identified in the stria. Unexpectedly, many Cl(-) and Ca(2+) transport systems were found, suggesting that the dynamics of these ions play multiple roles. Several transporters for organic substances were also detected. Network analysis demonstrated that a few kinases, including protein kinase A, and Ca(2+) were key regulators for the strial transports. In the library of channels and transporters, 19 new candidates for uncloned deafness-related genes were identified. These resources provide a platform for understanding the molecular mechanisms underlying the epithelial transport essential for cochlear function and the pathophysiological processes involved in hearing disorders.


Assuntos
Surdez/fisiopatologia , Proteínas de Membrana Transportadoras/metabolismo , Estria Vascular/metabolismo , Animais , Bases de Dados Genéticas , Surdez/genética , Humanos , Masculino , Proteínas de Membrana Transportadoras/genética , Camundongos , Dados de Sequência Molecular , Proteômica , Ratos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...