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2.
J Am Acad Audiol ; 2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38925160

RESUMEN

BACKGROUND: Simultaneous Multifrequency (SiMFy) is a time-saving and reliable stimulus to determine the frequency tuning of ocular vestibular-evoked myogenic potential (oVEMP); however, the absence of 4000 Hz in SiMFy potentially makes it a less potent tool for the diagnosis of Superior semicircular canal dehiscence, a pathology with an ever-increasing prevalence. Further, SiMFy was validated using only the infra-orbital (IO) electrode montage. However, the recordings obtained using the IO montage might be susceptible to reference contamination introduced by a small separation between the recording electrodes, and also susceptible to reflex impurity due to the spatially displaced reference electrode from the inferior oblique muscle (IOM), rendering it vulnerable to picking up responses from other muscles. Nonetheless, little is known about the similarities/differences between the SiMFy-induced oVEMPs using alternate montages [belly-tendon (BT), chin-reference (CR), and sternum-reference (SR)] and the non-simultaneous multifrequency oVEMPs (NSM-oVEMPs) using the IO montage. PURPOSE OF THE STUDY: To develop a modified SiMFy stimulus and investigate its effects on frequency tuning of oVEMP using various electrode montages. RESEARCH DESIGN: Within-subject experimental design. STUDY SAMPLE: Thirty-three healthy adults aged 20-30 years. DATA COLLECTION AND ANALYSIS: Tone bursts of octave and mid-octave frequencies from 250 Hz to 4000 Hz were generated and concatenated to create the modified SiMFy stimulus. All participants underwent non-simultaneous multifrequency oVEMPs and modified SiMFy oVEMPs using BT, CR, SR, and IO montages simultaneously. The response rate, peak-to-peak amplitude, and frequency tuning were compared between NSM-oVEMP and modified SiMFy oVEMP and also between the electrode montages. RESULTS: BT montage recorded the largest amplitude among the montages in non-simultaneous multifrequency stimulation and modified SiMFy stimulation. Although the response rates were comparable, the modified SiMFy produced significantly lower oVEMP amplitudes than the non-simultaneous multifrequency stimulation within each electrode montage (p < 0.05). A moderate-to-strong agreement on frequency tuning existed between the non-simultaneous multifrequency stimuli and modified SiMFy stimulus for all the montages, except for the SR montage. CONCLUSIONS: Although the modified SiMFy produces smaller amplitude oVEMPs than the non-simultaneous multifrequency stimulation for the respective montages, its use in combination with the BT montage yields higher response rates and larger peak-to-peak amplitudes than the non-simultaneous multifrequency recording using IO montage.

3.
Artículo en Inglés | MEDLINE | ID: mdl-38738729

RESUMEN

Melanocytes are highly specialized dendritic cells that deliver melanin to keratinocytes in melanosomes, which are subcellular organelles where melanin is produced and stored. Mammal's skin, hair, and eyes all contain the complex pigment melanin, which gives them color and ultraviolet protection. Melanins have the potential to be free radical sinks and are strong cation chelators. Amino acid tyrosine and its metabolite, dopa, are the precursors to complex metabolic processes that end with melanin production. Melanocytes generate different types and amounts of melanin, which is defined genetically and is impacted by several extrinsic and intrinsic factors such as hormone fluctuations, inflammation, age, and ultraviolet radiation exposure, leading to the stimulation of numerous melanogenesis pathways. Melasma, a common skin pigmentation condition, is associated with the overproduction of melanin and is characterized by brown to gray-brown and black spots that mostly affect the face. The present review addresses the regulatory mechanisms and signaling pathways involved in skin pigmentation with an emphasis on the altered melanogenesis that causes melasma and hyperpigmentation. The current study also illustrates the available treatment options with cellular and molecular mechanisms for the management of melasma. Understanding the mechanism of the pigmentation process may help researchers develop new therapeutic strategies and novel drugs for the management of melasma.

4.
Protein Expr Purif ; 221: 106504, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38782082

RESUMEN

Reteplase (recombinant plasminogen activator, rPA) is a mutant non-glycosylated tissue-type plasminogen activator (tPA) containing 355 amino acids with longer half-life and promising thrombolytic activity than its original counterpart, full length tPA. In this study, we aimed to produce and optimize the purification process of recombinant tissue-type plasminogen activator (tPA) known as Reteplase (rPA). Reteplase cDNA synthesized from total mRNA isolated from human placenta was PCR amplified, cloned into a pET-28a(+) E. coli expression vector and expressed in Rosetta-gami 2 E. coli (NovagenⓇ) host. rPA was expressed as an inclusion body in E. coli and its biological activity was achieved after single step solubilization, purification and refolding. We exploited the strategy of Slow Refolding using Gradual Dialysis (SRGD) in which a refolding buffer containing glutathione oxidized (1 mM GSSG) and glutathione reduced (3 mM GSH) and pH 9.0 was used. Using the SRGD method, we were able to successfully obtain the protein in its active form. We obtained 4.26 mg of active refolded protein from a 50 mL culture that was scaled up in a bioreactor. The purity and homogeneity of rPA was evaluated by SDS-PAGE, Western blotting and mass spectrometry. Circular dichroism spectroscopy was conducted to evaluate the refolding and stability of the refolded rPA in comparison to reference standard rPA. The thrombolytic potential of rPA was assessed by fibrin plate assay and In Vitro clot lysis assay. The presented protocol offers a viable approach for enhancing both the yield and refolding efficiency of reteplase, potentially resulting in an increase in yield.


Asunto(s)
Escherichia coli , Replegamiento Proteico , Proteínas Recombinantes , Activador de Tejido Plasminógeno , Activador de Tejido Plasminógeno/genética , Activador de Tejido Plasminógeno/química , Activador de Tejido Plasminógeno/aislamiento & purificación , Activador de Tejido Plasminógeno/biosíntesis , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/biosíntesis , Humanos , Expresión Génica , Fibrinolíticos/química , Fibrinolíticos/aislamiento & purificación , Clonación Molecular
5.
Artículo en Inglés | MEDLINE | ID: mdl-38659259

RESUMEN

Brain-related disorders include neuroinflammation, neurodegenerative disorders, and demyelination, which ultimately affect the quality of life of patients. Currently, brain-related disorders represent the most challenging health problem worldwide due to complex pathogenesis and limited availability of drugs for their management. Further, the available pharmacotherapy accompanies serious side effects, therefore, much attention has been directed toward the development of alternative therapy derived from natural sources to treat such disorders. Recently, flavonoids, natural phytochemicals, have been reported as a treatment option for preventing brain aging and disorders related to this. Among these flavonoids, dietary luteolin, a flavone, is found in many plant products such as broccoli, chamomile tea, and honeysuckle bloom having several pharmacological properties including neuroprotective activities. Therefore, the objective of this paper is to compile the available literature regarding the neuroprotective potential of luteolin and its mechanism of action. Luteolin exerts notable anti-inflammatory, antioxidant, and antiapoptotic activity suggesting its therapeutic efficacy in different neurological disorders. Numerous in-vivo and in-vitro experiments have revealed that luteolin exhibits neuroprotective potential via up-regulating the ER/ERK, PI3AKT, Nrf2 pathways and down-regulating the MAPK/JAK2STAT and NFκB pathways. Taking into account of available facts regarding the neuroprotective efficacy of luteolin, the current study highlights the beneficial effects of luteolin for the prevention, management, and treatment of different neurological disorders. Thus, luteolin can be considered an alternative for the development of new pharmacophores against various brain-related disorders.

6.
Angew Chem Int Ed Engl ; 63(11): e202401234, 2024 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-38252519

RESUMEN

Flexible thermoelectric devices of nanomaterials have shown a great potential for applications in wearable to remotely located electronics with desired shapes and geometries. Continuous powering up the low power flexible electronics is a major challenge. We are reporting a flexible thermoelectric module prepared from silver telluride (Ag2 Te) nanowires (NWs), which are chemically transformed from uniquely synthesized and scalable tellurium (Te) NWs. Conducting Ag2 Te NWs composites have shown an ultralow total thermal conductivity ~0.22 W/mK surpassing the bulk melt-grown Ag2 Te ~1.23 W/mK at ~300 K, which is attributed to the nanostructuring of the material. Flexible thermoelectric device consisting of 4 legs (n-type) of Ag2 Te NWs on polyvinylidene fluoride membrane displays a significant output voltage (Voc ) ~2.3 mV upon human touch and Voc ~18 mV at temperature gradient, ΔT ~50 K, which shows the importance of NWs based flexible thermoelectric devices to power up the low power wearable electronics.

7.
Artículo en Inglés | MEDLINE | ID: mdl-38243959

RESUMEN

Parkinson's disease (PD), the most common brain-related neurodegenerative disorder, is comprised of several pathophysiological mechanisms, such as mitochondrial dysfunction, neuroinflammation, aggregation of misfolded alpha-synuclein, and synaptic loss in the substantia nigra pars compacta region of the midbrain. Misfolded alpha-synuclein, originating from damaged neurons, triggers a series of signaling pathways in both glial and neuronal cells. Activation of such events results in the production and expression of several proinflammatory cytokines via the activation of the nuclear factor κB (NF-κB) signaling pathway. Consequently, this cascade of events worsens the neurodegenerative processes, particularly in conditions, such as PD and synucleinopathies. Microglia, astrocytes, and neurons are just a few of the many cells and tissues that express the NF-κB family of inducible types of transcription factors. The dual role of NF-κB activation can be crucial for neuronal survival, although the classical NF-κB pathway is important for controlling the generation of inflammatory mediators during neuroinflammation. Modulating NF-κB-associated pathways through the selective action of several agents holds promise for mitigating dopaminergic neuronal degeneration and PD. Several naturally occurring compounds in medicinal plants can be an effective treatment option in attenuating PD-associated dopaminergic neuronal loss via selectively modifying the NF-κB-mediated signaling pathways. Recently, flavonoids have gained notable attention from researchers because of their remarkable anti-neuroinflammatory activity and significant antioxidant properties in numerous neurodegenerative disorders, including PD. Several subclasses of flavonoids, including flavones, flavonols, isoflavones, and anthocyanins, have been evaluated for neuroprotective effects against in vitro and in vivo models of PD. In this aspect, the present review highlights the pathological role of NF-κB in the progression of PD and investigates the therapeutic potential of natural flavonoids targeting the NF-κB signaling pathway for the prevention and management of PD-like manifestations with a comprehensive list for further reference. Available facts strongly support that bioactive flavonoids could be considered in food and/or as lead pharmacophores for the treatment of neuroinflammation-mediated PD. Furthermore, natural flavonoids having potent pharmacological properties could be helpful in enhancing the economy of countries that cultivate medicinal plants yielding bioactive flavonoids on a large scale.

8.
Ear Hear ; 45(1): 227-238, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-37608435

RESUMEN

OBJECTIVES: Stimulus and recording parameters are pivotal for shaping the ocular vestibular-evoked myogenic potential (oVEMP). In the last decade, several attempts were made to identify the optimum electrode placement site to improve the oVEMP responses. A vast majority of these found larger response amplitudes for alternate electrode montages like belly-tendon (BT), chin-referenced (CR), and/or sternum-referenced montages than the clinically used infra-orbital montage. However, no study has yet compared all alternate electrode montages in a simultaneous recording paradigm to eliminate other confounding factors. Also, no study has compared all of them for their test-retest reliability, waveform morphology, and signal-to-noise ratio. Therefore, the decision on which among these electrode montages is best suited for oVEMP acquisition remains opaque. The present study aimed to investigate the effects of various electrode montages on oVEMP's response parameters and to determine the test-retest reliability of each of these in clinically healthy individuals using a simultaneous recording paradigm. DESIGN: This study had a within-subject experimental design. Fifty-five young healthy adults (age range: 20-30 years) underwent contralateral oVEMP recording using infra-orbital, BT, chin-referenced, and sternum-referenced electrode montages simultaneously using a four-channel evoked potential system. RESULTS: BT montage had a significantly shorter latency, larger amplitude, higher signal-to-noise ratio, and better morphology than other alternate montages ( p < 0.008). Further, all electrode montages of the current study showed fair/moderate to excellent test-retest reliability. CONCLUSIONS: By virtue of producing significantly better response parameters than the other electrode montages, BT montage seems better suited to the recording of oVEMP than the known electrode montages thus far.


Asunto(s)
Potenciales Vestibulares Miogénicos Evocados , Vestíbulo del Laberinto , Adulto , Humanos , Adulto Joven , Reproducibilidad de los Resultados , Potenciales Vestibulares Miogénicos Evocados/fisiología , Electrodos , Relación Señal-Ruido
9.
Front Neurol ; 14: 1288150, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38020643

RESUMEN

Introduction: Benign paroxysmal positional vertigo (BPPV) involving the posterior canal is more common than other canals; however, simultaneous involvement of multiple canals can be seen up to 20% of all BPPV cases. The diagnosis and management of multiple canal BPPV can be quite challenging due to the complexity of findings. Therefore, this systematic review and meta-analysis aimed at unveiling the most effective repositioning strategy for the treatment of multiple canal BPPV. Methods: A literature search through PubMed, Scopus, and Web of Science databases was conducted using search terms such as BPPV, multiple canals, bilateral BPPV, repositioning maneuvers etc. After duplicate removal, the retained articles underwent various stages of elimination by two independent reviewers, and a third reviewer resolved the discrepancy between them. Results: A total of 22 articles were included in the systematic review. These publications documented 5,196 patients diagnosed with BPPV, of which 513 had multiple canal BPPV. Of 295 individuals with multiple canal BPPV, 58.9% were effectively treated in 1 session, whereas 18.3 and 4.4% achieved a symptom-free state after two and three sessions, respectively. Failure of treatment using repositioning maneuvers was found in 18.4%. Possible implications: This study offers insight into the real world of BPPV management in single and multiple canal BPPV. It is evident that repositioning maneuvers provide rapid and long-lasting relief of BPPV in most single canal BPPV patients; however, multiple canal BPPV often requires repeated treatment, and the risk of recurrence is higher in this variety than the single canal BPPV.

10.
Artículo en Inglés | MEDLINE | ID: mdl-37817521

RESUMEN

Recently, Parkinson's disease (PD) has become a remarkable burden on families and society with an acceleration of population aging having several pathological hallmarks such as dopaminergic neuronal loss of the substantia nigra pars compacta, α-synucleinopathy, neuroinflammation, autophagy, last but not the least astrogliosis. Astrocyte, star-shaped glial cells perform notable physiological functions in the brain through several molecular and cellular mechanisms including nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. It has been well established that the downregulation of the astrocytic Nrf2 signaling pathway plays a crucial role in the pathogenesis of PD because it is a master regulator of cellular defense mechanism along with a regulator of numerous detoxifying and antioxidant enzymes gene expression. Fascinatingly, upregulation of the astrocytic Nrf2 signaling pathway attenuates the degeneration of nigrostriatal neurons, restores neuronal proliferation, rejuvenates astrocytic functions, and exhibits neuroprotective effects via numerous cellular and molecular mechanisms in the PD-like brain of the experimental animal. Here, we discuss the numerous in-vitro and in-vivo studies that evaluate the neuroprotective potential of the astrocytic Nrf2 signaling pathway against experimentally-induced PD-like manifestation. In conclusion, based on available preclinical reports, it can be assumed that the astrocytic Nrf2 signaling pathway could be an alternative target in the drug discovery process for the prevention, management, and treatment of PD.

11.
Int J Audiol ; 62(7): 635-643, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37393930

RESUMEN

OBJECTIVE: The present study aimed to investigate the findings of cervical, ocular and masseter vestibular evoked myogenic potentials (cVEMP, oVEMP and mVEMP) among Multiple sclerosis (MS) and correlate with clinical and MRI findings. DESIGN: Standard group comparison research design. STUDY SAMPLE: Individuals with relapsing-remitting MS (n = 45) and age-sex-matched controls (n = 45) were the participants. All of them underwent case history, neurological examination, cVEMP, oVEMP and mVEMP testing. MRI was obtained only for MS participants. RESULTS: Abnormal result on at least one vestibular evoked myogenic potential (VEMP) sub-type was evidenced in 95.56% of participants whereas, unilateral or bilateral abnormal result on all three VEMP sub-types was observed in 60% of participants. The mVEMP abnormality was higher (82.22%) than cVEMP (75.56%) and oVEMP (75.56%) abnormalities but the differences were not significant (p > 0.05). There was no significant association of VEMP abnormalities with the presence of the brainstem symptoms, the brainstem signs, or the MRI lesions (p > 0.05). In the MS group, 38% had normal brainstem MRI; however, mVEMP, cVEMP and oVEMP abnormalities were evidenced in 82.4%, 64.7% and 52.94%, respectively. CONCLUSIONS: Among the three VEMP sub-types, mVEMP appears to be of greater value in identifying silent brainstem dysfunction undetected by clinical and MRI findings in the MS population.


Asunto(s)
Esclerosis Múltiple , Potenciales Vestibulares Miogénicos Evocados , Humanos , Potenciales Vestibulares Miogénicos Evocados/fisiología , Esclerosis Múltiple/diagnóstico , Esclerosis Múltiple/patología , Tronco Encefálico , Imagen por Resonancia Magnética
12.
3 Biotech ; 13(7): 247, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37366498

RESUMEN

Phycobiliproteins is a family of chromophore-containing proteins having light-harvesting and antioxidant capacity. The phycocyanin (PC) is a brilliant blue coloured phycobiliprotein, found in rod structure of phycobilisome and has been widely studied for their therapeutic and fluorescent properties. In the present study, the hexameric assembly structure of phycocyanin (Syn-PC) from Synechococcus Sp. R42DM is characterized by X-ray crystallography to understand its light-harvesting and antioxidant properties. The crystal structure of Syn-PC is solved with 2.15 Å resolution and crystallographic R-factors, Rwork/Rfree, 0.16/0.21. The hexamer of Syn-PC is formed by heterodimer of two polypeptide chains, namely, α- and ß-subunits. The structure is analysed at atomic level to reveal the chromophore microenvironment and possible light energy transfer mechanism in Syn-PC. The chromophore arrangement in hexamer, deviation angle and distance between the chromophore contribute to the energy transfer efficiency of protein. The structural attributes responsible for the antioxidant potential of Syn-PC are recognized and annotated on its 3-dimensional structure. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03665-1.

13.
Int J Biol Macromol ; 242(Pt 2): 124810, 2023 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-37182622

RESUMEN

Hot-springs are regarded as the best source of industrially significant biocules and one of the unique locations for extremophiles. The α-amylase is one of the most important enzymes used in starch consuming industries, where the need of thermostability is paramount. In this study, the full metagenome sequences obtained from the soil of Tuwa hot-spring (Gujarat, India) were examined for the presence of several thermostable enzymes using bioinformatic techniques. The whole gene sequence for α-amylase was found from the metagenome. The α-amylase gene was amplified, cloned, and expressed in Escherichia coli and further characterized in vitro. The rm-α-amylase was found optimally active at 60 °C and at pH 6.0 and showed significantly high activity in 0.1 mM Co2+ as well as in other heavy metal ions without any effect on its thermostability. Apart from α-amylase activity the purified rm-α-amylase was also shown to hydrolyse agar, xylan, pectin, alginate and cellulose. To our knowledge, this is the first report of a new, multifunctional, thermostable amylase that was discovered from the hot-spring metagenomes. Owing to their multifunctionality, resilience towards high temperature and heavy metal ions, stability with solvents, additives and inhibitors, rm-α-amylase can be exploited for a variety of biotechnological applications.


Asunto(s)
Metagenoma , alfa-Amilasas , alfa-Amilasas/química , Estabilidad de Enzimas , India , Concentración de Iones de Hidrógeno , Temperatura
14.
Curr Mol Med ; 23(9): 889-900, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37254536

RESUMEN

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder, and its consequences severely influence the quality of a patient's life and mobility. PD is characterized by bradykinesias with tremors and/or rigidity. Pathophysiologically, PD is associated with the gradual degeneration of dopaminergic neurons in the substantia nigra pars compacta of the midbrain, neuroinflammation, increased accumulation of the alpha (α)-synuclein, overburden of oxidative stress, and mitochondrial dysfunction. To date, there are no effective therapies with underlying shreds of evidence that alters the progression of PD. Exendin-4, a glucagon-like peptide 1 (GLP-1) receptor agonist, has gained attention for its tremendous neuroprotective potential against numerous neurodegenerative disorders, including PD. Further, several pieces of research evidence have suggested the beneficial role of Exendin-4 in PD-like experimental models. The present review article highlights the preclinical and clinical evidence of the therapeutic benefits of Exendin-4 against PD. Exendin-4 reverses the PD-like symptoms in experimental animals by dramatically minimizing the loss of dopaminergic neuronal and accumulation of α-synuclein in the PD-like brain. Further, it also reduces the mitochondrial toxicity and expression of pro-inflammatory mediators such as tumor necrosis factor (TNF)-α and interleukin (IL)-1ß. These observations designate that Exendin-4 is a multifactorial compound that could be considered a safe, effective, and new ingredient for developing clinically useful pharmacotherapy for managing PD-like manifestations.


Asunto(s)
Fármacos Neuroprotectores , Enfermedad de Parkinson , Animales , Enfermedad de Parkinson/tratamiento farmacológico , Enfermedad de Parkinson/diagnóstico , Enfermedad de Parkinson/metabolismo , Exenatida/farmacología , Exenatida/metabolismo , Exenatida/uso terapéutico , Encéfalo/metabolismo , Estrés Oxidativo , Neuronas Dopaminérgicas/metabolismo , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/uso terapéutico
15.
Ear Hear ; 44(5): 940-948, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36859775

RESUMEN

OBJECTIVES: A recently devised parameter of vestibular-evoked myogenic potential (VEMP) based on the principles of frequency tuning is the inter-frequency amplitude ratio (IFAR). It refers to the ratio of the amplitude of 1000 Hz tone burst evoked VEMP to 500 Hz evoked tone burst. A pathology like Meniere's disease changes the frequency response and alters the frequency tuning of the otolith organs. Because IFAR is based on the principle of frequency tuning of VEMP, it is likely to help identify Meniere's disease. Few studies in the last decade have investigated the utility of IFAR in identifying Meniere's disease. However, a systematic review and a meta-analysis on IFAR in Meniere's disease are lacking. The present study investigates whether the IFAR of VEMP helps identify Meniere's disease and differentiates it from healthy ears and other vestibular pathologies. DESIGN: The present study is a systematic review and a meta-analysis. The studies investigating the IFAR of cervical and ocular VEMPs in Meniere's disease, healthy controls, and other vestibular pathologies were searched across research databases such as PubMed, Science Direct, and Scopus. The search strategy was developed using the PICO (population, intervention, comparison, and outcomes) format, and Medical Subject Headings (MeSH) terms and Boolean operators were employed. The systematic review was performed using the Rayyan software, whereas the Review Manager software was used to carry out the meta-analysis. A total of 16,605 articles were retrieved from the databases. After the duplicate removal, 2472 articles remained. These were eliminated using title screening, abstract screening, and full-length inspections. A total of nine articles were found eligible for quality assessment and meta-analysis, and the New Castle-Ottawa Scale was used for quality assessment. After the data extraction, 24 six articles were found to have the desired data format for the meta-analysis. RESULTS: The results showed significantly higher IFAR in the affected ears of individuals in the Meniere's disease group than in the control group's unaffected ears. There was no significant difference between the unaffected ears of individuals in the Meniere's disease group and the ears of the control group. The only study on Meniere's disease and benign paroxysmal positional vertigo found significantly larger ocular VEMP IFAR in ears with Meniere's disease than in benign paroxysmal positional vertigo. CONCLUSIONS: This systematic review and meta-analysis found IFAR efficient in differentiating Meniere's disease from healthy controls. We also found an enhanced IFAR as a potential marker for Meniere's disease. However, more investigations are needed to confirm the utility of an enhanced IFAR value in the exclusive identification of Meniere's disease.


Asunto(s)
Enfermedad de Meniere , Potenciales Vestibulares Miogénicos Evocados , Vestíbulo del Laberinto , Humanos , Enfermedad de Meniere/diagnóstico , Vértigo Posicional Paroxístico Benigno/diagnóstico , Potenciales Vestibulares Miogénicos Evocados/fisiología , Sáculo y Utrículo
16.
J Biomol Struct Dyn ; 41(9): 3752-3761, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-35354393

RESUMEN

Phycoerythrin (PE) is green light-absorbing pigment-protein that assists in efficient light harvesting in cyanobacteria and red-algae. PE in cyanobacteria stays less studied so far as compared to that in red algae. In this study, PE from marine cyanobacteria Halomicronema sp. R31DM is purified and subjected for its structural characterisation by X-ray crystallography in order to understand its light-harvesting characteristics. The crystal structure is solved to a resolution-limit of 2.21 Å with reasonable R-factors values, 0.16/0.21 (Rwork/ Rfree). PE forms hexamer of hetero-dimers made up of two peptide chains, α- and ß-subunits containing 2 and 3 phycoerythrobilin (PEB) chromophores covalently attached to them, respectively. Geometry of five chromophores is analysed along with their relative position within the PE hexamer. Also, their interactions with the surrounding microenvironment are analysed. The plausible energy transfer pathways in hexamer structure have been predicted based on relative position and geometry of chromophores. This structure enriches the structural information of cyanobacterial PE in order to understand its light-harvesting capacity.Communicated by Ramaswamy H. Sarma.


Asunto(s)
Cianobacterias , Ficoeritrina , Ficoeritrina/química , Ficoeritrina/metabolismo , Cianobacterias/química , Cianobacterias/metabolismo , Cristalografía por Rayos X , Péptidos/metabolismo
17.
Braz. J. Pharm. Sci. (Online) ; 59: e20200, 2023. graf
Artículo en Inglés | LILACS | ID: biblio-1505842

RESUMEN

Abstract The renin-angiotensin-aldosterone system (RAAS) plays a key role in diabetic nephropathy (DN). Angiotensin-II secreted during the RAAS pathway increases nephropathy. It stimulates oxidative stress which can quench nitric oxide. Reduced nitric oxide level aggravates Ang-II-induced vasoconstriction. Ang-II has also emerged as a central mediator of the glomerular hemodynamic changes that are associated with renal injury. Deletion of ACE2 is also noted due to increased Ang-II level which leads to the development of DN. We hypothesize that nephropathy caused by Ang-II in the periphery may be controlled by brain RAAS. ACE inhibitors and ARBs may show the renoprotective effect when administered through ICV without crossing the blood-brain barrier. DN was observed after 8 weeks of diabetes induction through alloxan. Administration of captopril and valsartan once and in combined therapy for 2 weeks, significantly reduced urine output, blood urea nitrogen, total protein in the urine, serum cholesterol, serum creatinine, serum triglycerides, and kidney/body weight ratio as compared to diabetic control rats. Further, combination therapy significantly increased the body weight and serum nitrate level as compared to diabetic control animals. However, increased ACE2 levels in the brain may reduce the sympathetic outflow and might have decreased the peripheral activity of Ang-II which shows beneficial effects in DN.


Asunto(s)
Animales , Masculino , Femenino , Ratas , Sistema Renina-Angiotensina/inmunología , Angiotensina II/análisis , Nefropatías Diabéticas/patología , Heridas y Lesiones/clasificación , Inhibidores de la Enzima Convertidora de Angiotensina/administración & dosificación , Peptidil-Dipeptidasa A/administración & dosificación
18.
Sci Rep ; 12(1): 21115, 2022 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-36477010

RESUMEN

In this work, an analytical model is developed for DM-DG-TMD-FET- based Biosensor including Fringing-field effects. The Analytical model has been developed for two different Device structures, namely Device structure-1 (without a gate above the nano-cavity) and Device structure-2 (with a gate above the nano-cavity) based on modulation of the dielectric constant of biomolecules in the nano-cavity region. The proposed model has been validated against both numerical quantum simulation results with the help of a few fitting parameters and it also agrees with the 2-dimensional numeric simulator SILVACO TCAD used in this work. The presence/absence of biomolecules has been detected by the metric of threshold voltage sensitivity [Formula: see text] and drain current [Formula: see text] for the neutral as well as charged biomolecules. Sensitivities of partially filled nano-cavities arising out of steric hindrance in both the biosensors are compared. Optimization of device dimensions has also been included in this work to enhance the sensitivity of the biosensors. It has been witnessed that the sensitivity of the proposed biosensor is [Formula: see text] 100% higher in Device structure-1 for neutral biomolecules with dielectric constant [Formula: see text] = 12, when compared to Device structure-2 for fully filled cavities. Whereas for the charged biomolecules, Device structure-1 shows [Formula: see text] 50% enhanced sensitivity than Device structure-2 for [Formula: see text] [Formula: see text]. Device structure-1 demonstrates [Formula: see text]120% higher sensitivity than Device structure-2 with partially filled cavities (i.e. 66% filled cavity). Finally, benchmarking of the proposed biosensor is presented with contemporary, state-of-the-art biosensors and it is highlighted that [Formula: see text] FET-based biosensor emerges with a superior sensitivity of [Formula: see text] = 0.81 V for [Formula: see text].

19.
J Speech Lang Hear Res ; 65(11): 4454-4468, 2022 11 17.
Artículo en Inglés | MEDLINE | ID: mdl-36279585

RESUMEN

PURPOSE: The aim of this study was to analyze the subcortical and cortical auditory evoked potentials for speech stimuli in children with speech-in-noise (SIN) deficits associated with auditory processing disorder (APD) without any reading or language deficits. METHOD: The study included 20 children in the age range of 9-13 years. Ten children were recruited to the APD group; they had below-normal scores on the speech-perception-in-noise test and were diagnosed as having APD. The remaining 10 were typically developing (TD) children and were recruited to the TD group. Speech-evoked subcortical (brainstem) and cortical (auditory late latency) responses were recorded and compared across both groups. RESULTS: The results showed a statistically significant reduction in the amplitudes of the subcortical potentials (both for stimulus in quiet and in noise) and the magnitudes of the spectral components (fundamental frequency and the second formant) in children with SIN deficits in the APD group compared to the TD group. In addition, the APD group displayed enhanced amplitudes of the cortical potentials compared to the TD group. CONCLUSION: Children with SIN deficits associated with APD exhibited impaired coding/processing of the auditory information at the level of the brainstem and the auditory cortex. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.21357735.


Asunto(s)
Trastornos de la Percepción Auditiva , Percepción del Habla , Niño , Humanos , Adolescente , Trastornos de la Percepción Auditiva/diagnóstico , Habla , Ruido , Percepción del Habla/fisiología , Potenciales Evocados Auditivos , Estimulación Acústica , Potenciales Evocados Auditivos del Tronco Encefálico/fisiología
20.
J Am Acad Audiol ; 33(3): 116-124, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-36216039

RESUMEN

BACKGROUND: To achieve balance, persons with blindness (PWB) use proprioceptive and vestibular cues rather than the visual system; however, PWB are equally susceptible to acquire vestibular disorders. Reliable assessments of the vestibular system in PWB are essential to determine the presence or absence of vestibular disorders. PURPOSE: The saccular and the utricular functioning can be assessed using cervical vestibular-evoked myogenic potential and ocular vestibular-evoked myogenic potential, respectively. Evaluation of the functional integrity of the semicircular canals requires an assessment of the vestibular ocular reflex; however, this can be challenging in PWB. Video head impulse test (vHIT) assesses the vestibular ocular reflex (VOR) elicited against the natural high-frequency head movement in the planes of all six semicircular canals. This study aimed to explore the feasibility and outcomes of administering vHIT in PWB. RESEARCH DESIGN: Standard (static) groups comparison. STUDY SAMPLE: Nineteen young PWB and 23 age-matched adults with "normal" vision (control group) were included in the study. DATA COLLECTION AND ANALYSES: PWB underwent vHIT once, while the control group was tested in three conditions; condition 1 was used to simulate blindness for the control group, where vHIT was done in a pitch-dark room without prior instructions; condition 2 included vHIT testing in daylight, without a fixed visual target and any instructions; and condition 3 involved vHIT in daylight in the presence of a set visual target and with standard instructions to maintain visual focus on the visual target. RESULTS: The VOR gain was abnormal in the PWB group for all the canals. Among the PWB, the lateral canals (mean = 0.63) had the best VOR gain, followed by the anterior canals (mean = 0.53) and the posterior canals (mean = 0.31). In the control group, the VOR gain was significantly reduced in condition 1. There was no significant difference between the VOR gain in the PWB group and the control group in condition 1 for the lateral and the anterior canals. A higher proportion of participants in the PWB group had the presence of refixation saccades. CONCLUSION: VOR is significantly reduced in PWB but not completely absent. There may be a need to develop normative data for blind individuals to decide whether or not a person with blindness has a vestibular dysfunction, specifically a VOR deficit.


Asunto(s)
Prueba de Impulso Cefálico , Enfermedades Vestibulares , Adulto , Ceguera , Estudios de Factibilidad , Humanos , Reflejo Vestibuloocular/fisiología , Canales Semicirculares , Enfermedades Vestibulares/diagnóstico
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