Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 219
Filtrar
Más filtros

Intervalo de año de publicación
1.
Proc Natl Acad Sci U S A ; 119(36): e2206104119, 2022 09 06.
Artículo en Inglés | MEDLINE | ID: mdl-36037386

RESUMEN

Viral hemorrhagic fevers caused by members of the order Bunyavirales comprise endemic and emerging human infections that are significant public health concerns. Despite the disease severity, there are few therapeutic options available, and therefore effective antiviral drugs are urgently needed to reduce disease burdens. Bunyaviruses, like influenza viruses (IFVs), possess a cap-dependent endonuclease (CEN) that mediates the critical cap-snatching step of viral RNA transcription. We screened compounds from our CEN inhibitor (CENi) library and identified specific structural compounds that are 100 to 1,000 times more active in vitro than ribavirin against bunyaviruses, including Lassa virus, lymphocytic choriomeningitis virus (LCMV), and Junin virus. To investigate their inhibitory mechanism of action, drug-resistant viruses were selected in culture. Whole-genome sequencing revealed that amino acid substitutions in the CEN region of drug-resistant viruses were located in similar positions as those of the CEN α3-helix loop of IFVs derived under drug selection. Thus, our studies suggest that CENi compounds inhibit both bunyavirus and IFV replication in a mechanistically similar manner. Structural analysis revealed that the side chain of the carboxyl group at the seventh position of the main structure of the compound was essential for the high antiviral activity against bunyaviruses. In LCMV-infected mice, the compounds significantly decreased blood viral load, suppressed symptoms such as thrombocytopenia and hepatic dysfunction, and improved survival rates. These data suggest a potential broad-spectrum clinical utility of CENis for the treatment of both severe influenza and hemorrhagic diseases caused by bunyaviruses.


Asunto(s)
Antivirales , Endonucleasas , Orthobunyavirus , Animales , Antivirales/farmacología , Evaluación Preclínica de Medicamentos , Farmacorresistencia Viral/efectos de los fármacos , Farmacorresistencia Viral/genética , Endonucleasas/antagonistas & inhibidores , Humanos , Ratones , Orthobunyavirus/efectos de los fármacos , Orthobunyavirus/genética , Orthobunyavirus/metabolismo , Replicación Viral/efectos de los fármacos
2.
Exp Brain Res ; 242(6): 1481-1493, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38702470

RESUMEN

The anterior (DA) and posterior parts of the deltoid (DP) show alternating contraction during shoulder flexion and extension movements. It is expected that an inhibitory spinal reflex between the DA and DP exists. In this study, spinal reflexes between the DA and DP were examined in healthy human subjects using post-stimulus time histogram (PSTH) and electromyogram averaging (EMG-A). Electrical conditioning stimulation was delivered to the axillary nerve branch that innervates the DA (DA nerve) and DP (DP nerve) with the intensity below the motor threshold. In the PSTH study, the stimulation to the DA and DP nerves inhibited (decrease in the firing probability) 31 of 54 DA motor units and 31 of 51 DP motor units. The inhibition was not provoked by cutaneous stimulation. The central synaptic delay of the inhibition between the DA and DP nerves was 1.5 ± 0.5 ms and 1.4 ± 0.4 ms (mean ± SD) longer than those of the homonymous facilitation of the DA and DP, respectively. In the EMG-A study, conditioning stimulation to the DA and DP nerves inhibited the rectified and averaged EMG of the DP and DA, respectively. The inhibition diminished with tonic vibration stimulation to the DA and DP and recovered 20-30 min after vibration removal. These findings suggest that oligo(di or tri)-synaptic inhibition mediated by group Ia afferents between the DA and DP exists in humans.


Asunto(s)
Músculo Deltoides , Estimulación Eléctrica , Electromiografía , Inhibición Neural , Humanos , Masculino , Adulto , Músculo Deltoides/fisiología , Músculo Deltoides/inervación , Femenino , Inhibición Neural/fisiología , Adulto Joven , Vibración , Vías Aferentes/fisiología
3.
Jpn J Clin Oncol ; 2024 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-38864253

RESUMEN

BACKGROUND: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has been used to diagnose and stage lung cancer. Acquire™ Pulmonary and Expect™ Pulmonary dedicated EBUS-TBNA needles were introduced as the Franseen and Lancet needles, respectively. It is still unclear whether the Franseen or Lancet needles yield a higher quality specimen especially focusing on next-generation sequencing-based molecular testing. METHODS: A single-center, prospective study performed at the Chiba University Hospital randomly assigned patients to two groups: Group A, wherein the first and second EBUS-TBNA were performed using Lancet and Franseen needles, respectively, and Group B, wherein the first and second EBUS-TBNA were performed using Franseen and Lancet needles, respectively. Each specimen was compared and analyzed pathologically. The primary outcome was the histological tissue area except blood clot and the cellularity of each sample. We also examined the success rate of molecular testing. RESULTS: Twelve patients who underwent EBUS-TBNA between November 2022 and February 2023 were enrolled in this study. The tissue area of the specimens obtained by the Franseen and Lancet needles was 13.3 ± 6.4 mm2 and 10.6 ± 6.3 mm2, respectively (P = .355). The tumor cellularity in the specimens obtained using the Franseen and Lancet needles was 54.0 ± 30.3 and 46.2 ± 36.3%, respectively (P = .608). The success rate of molecular testing using the single-pass sample by Franseen needle was 85.7 and 57.1% by Lancet needle. No serious complications were reported. CONCLUSIONS: The Franseen needle tended to show a greater amount of specimen with higher tumor cellularity than the Lancet needle which may contribute higher success rate of molecular testing. Further studies must be conducted to validate the results of this study. KEY FINDINGS: What is known and what is new?  What is the implication, and what should change now?

4.
BMC Pulm Med ; 24(1): 101, 2024 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-38413932

RESUMEN

BACKGROUND: Pulmonary arterial hypertension is a serious medical condition. However, the condition is often misdiagnosed or a rather long delay occurs from symptom onset to diagnosis, associated with decreased 5-year survival. In this study, we developed and tested a deep-learning algorithm to detect pulmonary arterial hypertension using chest X-ray (CXR) images. METHODS: From the image archive of Chiba University Hospital, 259 CXR images from 145 patients with pulmonary arterial hypertension and 260 CXR images from 260 control patients were identified; of which 418 were used for training and 101 were used for testing. Using the testing dataset for each image, the algorithm outputted a numerical value from 0 to 1 (the probability of the pulmonary arterial hypertension score). The training process employed a binary cross-entropy loss function with stochastic gradient descent optimization (learning rate parameter, α = 0.01). In addition, using the same testing dataset, the algorithm's ability to identify pulmonary arterial hypertension was compared with that of experienced doctors. RESULTS: The area under the curve (AUC) of the receiver operating characteristic curve for the detection ability of the algorithm was 0.988. Using an AUC threshold of 0.69, the sensitivity and specificity of the algorithm were 0.933 and 0.982, respectively. The AUC of the algorithm's detection ability was superior to that of the doctors. CONCLUSION: The CXR image-derived deep-learning algorithm had superior pulmonary arterial hypertension detection capability compared with that of experienced doctors.


Asunto(s)
Aprendizaje Profundo , Hipertensión Arterial Pulmonar , Humanos , Inteligencia Artificial , Hipertensión Arterial Pulmonar/diagnóstico por imagen , Rayos X , Tórax
5.
Ophthalmic Res ; 67(1): 23-28, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38071969

RESUMEN

INTRODUCTION: Heat shock protein (Hsp) 90 is one of the most abundant proteins in unstressed cells and regulates stability and functional maintenance of client proteins. In ocular tissue, Hsp90 is widely expressed in the cornea and retina and has multiple roles in these tissues. The expression of HSPs was induced in the retinas of glaucomatous patients and laser-induced glaucoma in monkey while their mechanisms remain to be elucidated. For this reason, we tried to elucidate the role of Hsp90 in intraocular pressure (IOP) regulation in rabbits. METHODS: IOP was measured by a pneumatonometer before and after intracameral injection of Hsp90 inhibitors. The aqueous flow rate was measured by fluorophotometry. Trans-epithelial electrical resistance was measured in primary human trabecular meshwork cells. RESULTS: 17-AAG, a specific Hsp90 inhibitor, significantly lowered IOP at concentrations of more than 30 µm in normotensive rabbits. Other Hsp90 inhibitors also significantly lowered IOP in normotensive rabbits at a dose of 100 µm. No reduction of aqueous humor production was observed by injection of 17-AAG in rabbits. Topical administration of pilocarpine tended to attenuate the IOP-lowering effects induced by the Hsp90 inhibitor. No reduction of trans-epithelial electrical resistance was observed by inhibition of Hsp90 in culture cells. CONCLUSIONS: These results indicated that intraocular Hsp90 regulates IOP, and the inhibition of Hsp90 by Hsp90 inhibitor decreases IOP without affecting aqueous humor production in rabbits. Further research in elucidating the mechanism of Hsp90 inhibitors will result in a better understanding of the role of Hsp90 in the regulation of IOP.


Asunto(s)
Benzoquinonas , Glaucoma , Presión Intraocular , Lactamas Macrocíclicas , Animales , Conejos , Humanos , Humor Acuoso/metabolismo , Proteínas de Choque Térmico/metabolismo , Proteínas de Choque Térmico/farmacología
6.
Int J Mol Sci ; 25(4)2024 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-38396796

RESUMEN

Estrogen, well known as a female hormone, is synthesized primarily by ovarian aromatase. However, extra-glandular tissues also express aromatase and produce estrogen. It is noteworthy that aromatase in gastric parietal cells begins expression around 20 days after birth and continues secreting considerable amounts of estrogen into the portal vein throughout life, supplying it to the liver. Estrogen, which is secreted from the stomach, is speculated to play a monitoring role in blood triglyceride, and its importance is expected to increase. Nevertheless, the regulatory mechanisms of the aromatase expression remain unclear. This study investigated the influence of transforming growth factor α (TGFα) on gastric aromatase expression during postnatal development. The administration of TGFα (50 µg/kg BW) to male Wistar rats in the weaning period resulted in enhanced aromatase expression and increased phosphorylated ERK1+2 in the gastric mucosa. By contrast, administration of AG1478 (5 mg/kg BW), a protein tyrosine kinase inhibitor with high selectivity for the epidermal growth factor receptor and acting as an antagonist of TGFα, led to the suppression of aromatase expression. In fact, TGFα expression in the gastric fundic gland isthmus began around 20 days after birth in normal rats as did that of aromatase, which indicates that TGFα might induce the expression of aromatase in the parietal cells concomitantly.


Asunto(s)
Células Parietales Gástricas , Factor de Crecimiento Transformador alfa , Ratas , Masculino , Femenino , Animales , Células Parietales Gástricas/metabolismo , Factor de Crecimiento Transformador alfa/metabolismo , Ratas Wistar , Aromatasa/genética , Aromatasa/metabolismo , Mucosa Gástrica/metabolismo , Estrógenos/metabolismo
7.
Int J Mol Sci ; 25(2)2024 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-38256184

RESUMEN

The 21-residue peptide α3, which is artificially designed and consists of three repeats of 7 residues, is known to rapidly assemble into the α-helix nanofiber. However, its molecular structure within the fiber has not yet been fully elucidated. Thus, we conducted a thorough investigation of the fiber's molecular structure using solid-state NMR and other techniques. The molecules were found to be primarily composed of the α-helix structure, with some regions near the C- and N-terminal adopting a 310-helix structure. Furthermore, it was discovered that ß-sheet hydrogen bonds were formed between the molecules at both ends. These intermolecular interactions caused the molecules to assemble parallelly in the same direction, forming helical fibers. In contrast, we designed two molecules, CaRP2 and ßKE, that can form ß-sheet intermolecular hydrogen bonds using the entire molecule instead of just the ends. Cryo-EM and other measurements confirmed that the nanofibers formed in a cross ß structure, albeit at a slow rate, with the formation times ranging from 1 to 42 days. To create peptide nanofibers that instantaneously respond to changes in the external environment, we designed several molecules (HDM1-3) based on α3 by introducing metal-binding sites. One of these molecules was found to be highly responsive to the addition of metal ions, inducing α-helix formation and simultaneously assembling into nanofibers. The nanofibers lost their structure upon removal of the metal ion. The change occurred promptly and was reversible, demonstrating that the intended level of responsiveness was attained.


Asunto(s)
Nanofibras , Microscopía por Crioelectrón , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Péptidos , Espectroscopía de Resonancia Magnética
8.
J Am Chem Soc ; 145(42): 22925-22933, 2023 10 25.
Artículo en Inglés | MEDLINE | ID: mdl-37828719

RESUMEN

Silk fibroin is stored in the silk glands of Bombyx mori silkworms as a condensed aqueous solution called liquid silk. It is converted into silk fibers at the silkworm's spinnerets under mechanical forces including shear stress and pressure. However, the detailed mechanism of the structural transition of liquid silk to silk fibers under pressure is not well understood. Magic angle spinning (MAS) in solid-state nuclear magnetic resonance (NMR) can exert pressure on liquid samples in a quantitative manner. In this study, solid-state NMR was used to quantitatively analyze the impact of pressure on the structural transition of liquid silk. A combination of 13C DD-MAS and CP-MAS NMR measurements enabled the conformation and dynamics of the crystalline region of the silk fibroin (both before (Silk Ip) and after (Silk IIp) the structural transition) to be detected in real time with atomic resolution. Spectral analyses proposed that the pressure-induced structural transition from Silk Ip to Silk IIp proceeds by a two-step autocatalytic reaction mechanism. The first reaction step is a nucleation step in which Silk Ip transforms to single lamellar Silk IIp, and the second is a growth step in which the single lamellar Silk IIp acts as a catalyst that reacts with Silk Ip molecules to further form Silk IIp molecules, resulting in stacked lamellar Silk IIp. Furthermore, the rate constant in the second step shows a significant pressure dependence, with an increase in pressure accelerating the formation of large stacked lamellar Silk IIp.


Asunto(s)
Bombyx , Fibroínas , Animales , Seda/química , Bombyx/química , Fibroínas/química , Espectroscopía de Resonancia Magnética/métodos , Conformación Proteica
9.
Langmuir ; 39(50): 18594-18604, 2023 12 19.
Artículo en Inglés | MEDLINE | ID: mdl-38060376

RESUMEN

Skin plays an important role in protecting the human body from the environment, dehydration, and infection. Burns, wounds, and disease cause the skin to lose its role, but tissue-engineered skin substitutes offer the opportunity to restore skin loss. Silk fibroin from Bombyx mori (SF) has proven to be an excellent wound dressing material. In this study, we aim to develop an excellent wound dressing material by introducing three-residue sequence Arg-Gly-Asp (RGD), which is the most well-known adhesion site of fibronectin, in the films of SF and the model peptide. Its usefulness as a wound dressing material was evaluated both in vitro and in vivo. First, we showed that the flexible structures of the RGD sequence are still maintained in SF with a rigid antiparallel ß-sheet structure using NMR in association with excellent wound dressings of SF containing RGD. Then, in in vitro experiments, two types of normal cells derived from human skin, normal human neonatal epidermal keratinocytes and normal human neonatal dermal fibroblasts, were used to evaluate the cell adhesion. On the other hand, in in vivo experiments, the study was conducted using a rat model of a whole skin layer defect wound. The results showed that the high-functionalized SF developed here has the potential to play a significant role in the field of wound dressings.


Asunto(s)
Bombyx , Fibroínas , Animales , Ratas , Humanos , Fibroínas/química , Bombyx/química , Cicatrización de Heridas , Oligopéptidos/química , Péptidos/química , Vendajes , Seda/química
10.
J Pharmacol Sci ; 151(1): 28-36, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36522120

RESUMEN

Triamcinolone acetonide (TA) has been shown to improve morphological and functional outcome in diabetic macular edema (DME) patients. However, the functional mechanism of TA has not been elucidated yet. In this study we investigated the detailed functional mechanism of TA using culture cells and retinopathy mouse models in which retinal inflammation and abnormal angiogenesis were induced by pericyte depletion. TA significantly prevented retinal hemorrhage, edema and partially improved abnormal angiogenesis. TA decreased retinal vascular endothelial growth factor (VEGF) concentration, presumably by preventing recruitment of macrophages into retina and TA also inhibited expression of inflammatory cytokines in retina. TA inhibited proliferation/migration of vascular endothelial cells and vessel sprouting. No direct inhibition of VEGF receptor 2 (VEGFR2) autophosphorylation was observed by TA. These results suggested that TA improved inflammatory retinal events which were induced in pericyte-deleted mice by mainly decreasing macrophage-derived VEGF and expression of inflammatory cytokines followed by attenuation of vascular permeability and proliferation/migration of endothelial cells. Furthermore, in these processes, translocation of glucocorticoid receptor (GR) was partially involved.


Asunto(s)
Retinopatía Diabética , Edema Macular , Ratones , Animales , Triamcinolona Acetonida/farmacología , Triamcinolona Acetonida/uso terapéutico , Factor A de Crecimiento Endotelial Vascular , Retinopatía Diabética/tratamiento farmacológico , Pericitos , Células Endoteliales/metabolismo , Retina/metabolismo , Inflamación/tratamiento farmacológico , Citocinas
11.
BMC Endocr Disord ; 23(1): 239, 2023 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-37904164

RESUMEN

BACKGROUND: Autoantibodies develop in autoimmune diseases, cancer, diabetes mellitus (DM), and atherosclerosis-related diseases. However, autoantibody biomarkers have not been successfully examined for diagnosis and therapy. METHODS: Serological identification of antigens through recombinant cDNA expression cloning (SEREX) was used for primary screening of antigens. The cDNA product was expressed in bacteria and purified. Amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) was used to evaluate antibody levels in serum samples. RESULTS: Phosphoenolpyruvate carboxykinase 1 (PCK1) was recognized as an antigen by serum IgG antibodies in the sera of patients with atherosclerosis. AlphaLISA showed significantly higher serum antibody levels against recombinant PCK1 protein in patients with DM and cardiovascular disease than in healthy donors, but not in those with acute ischemic stroke, transient ischemic attack, or obstructive sleep apnea syndrome. The area under the receiver operating characteristic curve for anti-PCK1 antibodies was 0.7024 for DM. The serum anti-PCK1 antibody levels were associated with age, platelet count, and blood pressure. Anti-PCK1-antibody-positive patients showed significantly lower overall survival than the negative patients. CONCLUSIONS: Serum anti-PCK1 antibody levels were found to be associated with DM. The anti-PCK1 antibody marker is useful for predicting the overall survival of patients with DM.


Asunto(s)
Aterosclerosis , Diabetes Mellitus , Accidente Cerebrovascular Isquémico , Humanos , ADN Complementario , Pronóstico , Diabetes Mellitus/diagnóstico , Autoanticuerpos , Proteínas Recombinantes , Fosfoenolpiruvato Carboxiquinasa (GTP) , Péptidos y Proteínas de Señalización Intracelular
12.
Surg Today ; 53(3): 369-378, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36018416

RESUMEN

PURPOSE: Neurologic adverse events (NAEs) are a major complication after pulmonary endarterectomy (PEA) performed under periods of deep hypothermic circulatory arrest (HCA) for chronic thromboembolic pulmonary hypertension. We modified the PEA strategy to prevent NAEs and evaluated the effectiveness of these modifications. METHODS: We reviewed the surgical outcomes of 87 patients divided into the following three groups based on the surgical strategy used: group S (n = 49), periods of deep HCA with alpha-stat strategy; group M1 (n = 19), deep HCA with modifications of slower cooling and rewarming rates and the pH-stat strategy for cooling: and group M2 (n = 13), multiple short periods of moderate HCA. RESULTS: PEA provided significant improvement of pulmonary hemodynamics in each group. Sixteen (29%) of the 49 group S patients suffered NAEs, associated with total circulatory arrest time (cutoff, 57 min) and Jamieson type I disease. The Group M1 and M2 patients did not suffer NAEs, although the group M1 patients had prolonged cardiopulmonary bypass (CPB) and more frequent respiratory failure. CONCLUSIONS: NAEs were common after PEA performed under periods of deep HCA. The modified surgical strategy could decrease the risk of NAEs but increase the risk of respiratory failure. Multiple short periods of moderate HCA may be useful for patients at risk of NAEs.


Asunto(s)
Hipotermia Inducida , Insuficiencia Respiratoria , Humanos , Puente Cardiopulmonar , Endarterectomía , Hipotermia Inducida/efectos adversos , Pulmón , Insuficiencia Respiratoria/etiología
13.
Eur J Neurosci ; 56(6): 4901-4913, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35902884

RESUMEN

Wrist position is known to affect the grip strength. We focused on the spinal reflex arc, which would support the movement, and investigated the effects of low-threshold afferents from the extensor carpi radialis (ECR) on the excitability of the flexor digitorum superficialis (FDS) motoneurons using the post-stimulus time-histogram (PSTH) and electromyogram-averaging (EMG-A) methods. Electrical conditioning stimulation of an intensity below the motor threshold was applied to the radial nerve branch innervating the ECR. In the PSTH study, changes in the firing probability of single motor units after electrical conditioning stimulation were investigated in seven subjects. An early and significant peak (increase in the firing probability: facilitation) was recorded for 36/60 FDS motor units. The remaining 24 motor units did not show any effects. Weak mechanical conditioning stimulation of the ECR muscle belly induced a similar peak. The central latency of the facilitation was equivalent to that of the homonymous monosynaptic facilitation. In the EMG-A study, changes in the rectified and averaged electromyograms of FDS induced by conditioning stimulation were examined in 12 subjects. An early and significant peak (facilitation) was induced by both electrical and mechanical conditioning stimulations. The facilitation decreased after withdrawal of the vibration to the ECR muscle belly. The facilitation was never induced by cutaneous nerve stimulation in the PSTH and EMG-A studies. These findings suggest that Group Ia afferents from the ECR increase the excitability of FDS motoneurons through a monosynaptic path in the spinal cord. These reflex arcs likely facilitate hand grasping movements.


Asunto(s)
Neuronas Motoras , Muñeca , Electromiografía , Mano , Humanos , Neuronas Motoras/fisiología , Músculo Esquelético/fisiología , Muñeca/fisiología
14.
Histochem Cell Biol ; 157(2): 195-204, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34807301

RESUMEN

The stomach has diverse functions other than gastric acid secretion. Multifaceted studies have investigated age-related changes of the gastrointestinal tract. Nevertheless, little is known about estrogen production changes in gastric parietal cells in rats aged over 3 months. We investigated age-related changes in gastric estrogen synthesis and the accompanying changes in liver estrogen receptor from 3 to 24 months. Weights of the body, stomach, and liver increased linearly from 3 to 18 months, then maintained a constant proportion up to 24 months. The gastric mucosa area (in mm2/1 mm muscularis mucosa) showed a constant proportion throughout the rats' life. The population of parietal cells immunostained area with H+/K+-ATPase decreased gradually with advancing age. Cells that were immunopositive to aromatase antibody were observed at 3-24 months. The expressions of aromatase mRNA and its protein were somewhat lower at 18 and 24 months than at 3 months. The portal venous estradiol concentration at 12 months was 1.5 times higher than that at 3 months, and that at 18 months was a half of that at 3 months. The expression of estrogen receptor mRNA in the liver at 18 and 24 months was about 80% of that at 3 months. Results suggest that the gastric estrogen production declines with aging, and the liver estrogen receptor is also affected accordingly. Simultaneously, the gastric mucosa continues to express aromatase to maintain liver function(s) throughout the animal's life.


Asunto(s)
Estrógenos/biosíntesis , Mucosa Gástrica/metabolismo , Células Parietales Gástricas/metabolismo , Factores de Edad , Animales , Masculino , Ratas , Ratas Wistar
15.
Biomacromolecules ; 23(12): 5095-5105, 2022 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-36449573

RESUMEN

The conformational transition of [3-13C]Ser- and [3-13C]Tyr-Antheraea yamamai silk fibroin before spinning induced by stretching was investigated with 13C CP/MAS NMR spectroscopy. The α-helix content of the silk fibroin before stretching was found to be 31.6% based on the Ala and Ser peaks. With increasing stretching ratio, the α-helix and the random coil Ala Cß peaks decreased gradually, while the ß-sheet peak was observed at a stretching ratio of ×5 and increased rapidly upon further stretching. For Ser residue, the α-helix peak decreased monotonically with increasing stretching ratio, but the random coil peak increased slightly till the stretching ratio of ×5 and then decreased. A small ß-sheet peak was observed before stretching and then increased rapidly starting from the stretching ratio of ×7. In contrast, a gradual decrease of random coil peak and an increase of ß-sheet peak were observed for the Tyr residue. The results of this investigation may be helpful for further studies of fiber formation mechanism in A. yamamai and in the future design of artificial silk materials.


Asunto(s)
Bombyx , Fibroínas , Mariposas Nocturnas , Animales , Fibroínas/química , Bombyx/química , Conformación Proteica , Seda/química , Espectroscopía de Resonancia Magnética/métodos
16.
Exp Brain Res ; 240(4): 1057-1067, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35201382

RESUMEN

Effects of low-threshold afferents from the anterior (DA), middle (DM) and posterior parts of the deltoid (DP) on the excitability of biceps brachii (BB) motoneurons in humans were studied. We evaluated the effects on individual motor units and motoneuron pool using a post-stimulus time-histogram (PSTH) and an electromyogram-averaging (EMG-A) methods, respectively, in 11 healthy human subjects. Electrical conditioning stimulation was delivered to the axillary nerve branch innervating DA (DA nerve), DM (DM nerve) and DP (DP nerve) with the intensity below the motor threshold. In the PSTH study, stimulation to the DA, DM and DP nerves produced a significant peak (facilitation) in 26/40 (65%), 28/47 (59%) and 0/32 (0%) of BB motor units, respectively. Since the central latency of the facilitation from the DA and DM nerves was 0.1 ± 0.3 and 0.1 ± 0.2 ms (mean ± S.D.) longer than that of the homonymous monosynaptic Ia facilitation of BB, respectively, the facilitation thus being compatible with monosynaptic path. In the EMG-A study, stimulation to the DA and DM nerves produced a significant peak (facilitation) for the BB motoneuron pool in all the subjects, whereas stimulation to the DP nerve produced no effect on BB. The facilitation diminished by vibration stimulation, and the suppression lasted for 30-40 min after removal of the vibration. Therefore, group Ia afferents should be responsible for the facilitation. These findings suggest that monosynaptic facilitation mediated by group Ia afferents from the DA and DM nerves to BB motoneurons exists in humans.


Asunto(s)
Neuronas Motoras , Músculo Esquelético , Estimulación Eléctrica , Electromiografía , Humanos , Neuronas Motoras/fisiología , Músculo Esquelético/fisiología , Vibración
17.
BMC Pulm Med ; 22(1): 138, 2022 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-35395844

RESUMEN

BACKGROUND: The pathogenesis of chronic thromboembolic pulmonary hypertension (CTEPH) is considered to be associated with chronic inflammation; however, the underlying mechanism remains unclear. Recently, altered gut microbiota were found in patients with pulmonary arterial hypertension (PAH) and in experimental PAH models. The aim of this study was to characterize the gut microbiota in patients with CTEPH and assess the relationship between gut dysbiosis and inflammation in CTEPH. METHODS: In this observational study, fecal samples were collected from 11 patients with CTEPH and 22 healthy participants. The abundance of gut microbiota in these fecal samples was assessed using 16S ribosomal ribonucleic acid (rRNA) gene sequencing. Inflammatory cytokine and endotoxin levels were also assessed in patients with CTEPH and control participants. RESULTS: The levels of serum tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-8, and macrophage inflammatory protein (MIP)-1α were elevated in patients with CTEPH. Plasma endotoxin levels were significantly increased in patients with CTEPH (P < 0.001), and were positively correlated with TNF-α, IL-6, IL-8, and MIP-1α levels. The 16S rRNA gene sequencing and the principal coordinate analysis revealed the distinction in the gut microbiota between patients with CTEPH (P < 0.01) and control participants as well as the decreased bacterial alpha-diversity in patients with CTEPH. A random forest analysis for predicting the distinction in gut microbiota revealed an accuracy of 80.3%. CONCLUSION: The composition of the gut microbiota in patients with CTEPH was distinct from that of healthy participants, which may be associated with the elevated inflammatory cytokines and endotoxins in CTEPH.


Asunto(s)
Microbioma Gastrointestinal , Hipertensión Pulmonar , Hipertensión Arterial Pulmonar , Citocinas , Endotoxinas , Humanos , Inflamación , Interleucina-8 , Japón , ARN Ribosómico 16S/genética , Factor de Necrosis Tumoral alfa
18.
Molecules ; 27(23)2022 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-36500566

RESUMEN

Spider dragline silk has unique characteristics of strength and extensibility, including supercontraction. When we use it as a biomaterial or material for textiles, it is important to suppress the effect of water on the fiber by as much as possible in order to maintain dimensional stability. In order to produce spider silk with a highly hydrophobic character, based on the sequence of ADF-3 silk, we produced recombinant silk (RSSP(VLI)) where all QQ sequences were replaced by VL, while single Q was replaced by I. The artificial RSSP(VLI) fiber was prepared using formic acid as the spinning solvent and methanol as the coagulant solvent. The dimensional stability and water absorption experiments of the fiber were performed for eight kinds of silk fiber. RSSP(VLI) fiber showed high dimensional stability, which is suitable for textiles. A remarkable decrease in the motion of the fiber in water was made evident by 13C solid-state NMR. This study using 13C solid-state NMR is the first trial to put spider silk to practical use and provide information regarding the molecular design of new recombinant spider silk materials with high dimensional stability in water, allowing recombinant spider silk proteins to be used in next-generation biomaterials and materials for textiles.


Asunto(s)
Seda , Agua , Seda/química , Agua/química , Espectroscopía de Resonancia Magnética/métodos , Proteínas Recombinantes/química , Materiales Biocompatibles/química , Proteínas de Artrópodos
19.
Minim Invasive Ther Allied Technol ; 31(6): 894-901, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34726557

RESUMEN

INTRODUCTION: We evaluated the safety margin in patients with hepatocellular carcinoma (HCC) in the hepatic dome who underwent computed tomography (CT)- or ultrasound (US)-guided radiofrequency ablation (RFA). MATERIAL AND METHODS: Included in this single-center study were 46 patients with 56 HCCs in the hepatic dome undergoing RFA after transarterial chemoembolization from January 2009 to December 2016. Thirty were addressed with CT fluoroscopy and 26 with US guidance. The technical success, safety margin, and local tumor progression (LTP) were evaluated. RESULTS: Technical success rate was 100% in the CT-RFA and 84.6% in the US-RFA group (p = .04). The average safety margin was 4.8 mm in the CT-RFA and 3.0 mm in the US-RFA group (p = .01). There was no LTP among the HCCs with a safety margin >3 mm achieved in 73.3% CT-RFA and 42.3% US-RFA group tumors (p = .03). Of the US-RFA group, six required additional RFA. There was no significant inter-group difference in LTP (p = .36). CONCLUSION: CT-guided RFA was superior to US-guided RFA with respect to the technical success rate and the acquisition of an appropriate safety margin in patients with HCC in the hepatic dome.


Asunto(s)
Carcinoma Hepatocelular , Ablación por Catéter , Quimioembolización Terapéutica , Neoplasias Hepáticas , Ablación por Radiofrecuencia , Carcinoma Hepatocelular/patología , Carcinoma Hepatocelular/cirugía , Ablación por Catéter/métodos , Quimioembolización Terapéutica/métodos , Humanos , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/cirugía , Estudios Retrospectivos , Tomografía Computarizada por Rayos X/métodos , Resultado del Tratamiento
20.
J Neurophysiol ; 126(4): 1137-1147, 2021 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-34495775

RESUMEN

After vibration, Hoffmann reflex (H reflex) amplitude is depressed; however, the mechanisms underlying these phenomena remain unknown. This study investigated the influence of frequency and duration of vibration on the H reflex amplitude, heteronymous facilitation of the tendon jerk (T wave) mediated by group Ia afferents, and cervicomedullary motor evoked potential (CMEP) amplitude in 18 healthy human subjects. The H reflex of the flexor carpi radialis (FCR) was induced by median nerve stimulation at the elbow, and the conditioning FCR stimulation enhanced the T wave of the biceps brachii (BB). After vibration was applied to the FCR muscle belly, the amplitudes of the H reflex and heteronymous facilitation of the T wave were depressed; these influences persisted after the removal of vibration in all subjects. For the H reflex, there was no difference in the amount of depression among the frequencies of vibration used (57, 77, and 100 Hz). Higher frequencies of vibration were associated with longer recovery times of postvibration depression, and a longer duration of vibration was associated with a longer recovery time of the depression. Similar results were observed for heteronymous facilitation of the T wave, suggesting that the depression is caused by a decrease in postsynaptic potentials evoked by Ia afferents in spinal motoneurons; it was probably due to reduction in the number of Ia afferents recruited by the median nerve stimulation. Moreover, because the FCR CMEP amplitude was depressed after vibration, vibration should affect the responsiveness of spinal motoneurons. These mechanisms are considered to contribute to the H reflex depression after vibration.NEW & NOTEWORTHY Vibration decreased the responsiveness of Ia afferents from the muscle exposed to vibration, and the duration of depressive effect was modulated by the duration and frequency of the vibration: a longer duration and a higher frequency of vibration led to a longer recovery time of the depression. In addition to this presynaptic effect, it also depressed the responsiveness of spinal motoneurons, indicating postsynaptic inhibition through specific circuits triggered by Ia impulses.


Asunto(s)
Médula Cervical/fisiología , Potenciales Evocados Motores/fisiología , Reflejo H/fisiología , Bulbo Raquídeo/fisiología , Neuronas Motoras/fisiología , Músculo Esquelético/fisiología , Neuronas Aferentes/fisiología , Vibración , Adulto , Femenino , Humanos , Masculino , Estimulación Física , Adulto Joven
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA