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1.
J Neurophysiol ; 130(1): 199-211, 2023 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-37377219

RESUMO

Imperceptible tactile noise applied to the skin of the feet enhances posture-correcting cutaneous reflexes. This sensory augmentation technique, stochastic resonance (SR), has not been tested in the less-sensitive hairy skin of the leg for its reflex-enhancement ability. The objectives of this study were to determine whether calf skin stimulation produces cutaneous reflexes and whether noise can modify the reflex. In 20 participants, electrotactile pulse trains were applied at the calf while participants performed submaximal isometric knee extension. To test SR, five different levels of vibrotactile noise were applied simultaneously to the test input. Muscle activity from the vastus lateralis (VL) was analyzed 60-110 ms after stimulation. Reflex ratios were calculated by dividing the reflex peak activity by the prestimulation background muscle activity. A significant reflex response was evoked in 16/20 participants (5.41 ± 2.6% of background muscle activity); these responses varied between individuals with eight being facilitatory and eight being inhibitory. In half of the participants, a new reflex appeared at some level of added noise (n = 10). The average reflex ratio of the study population was significantly higher at the "optimal" noise level (8.61 ± 4.5) than at "baseline" (4.70 ± 5.6) (P = 0.002); the optimal level varied across participants. These results suggest that cutaneous reflexes exist at the VL in response to calf skin stimulation and that SR can change cutaneous reflexes at the leg. This study provides an important first step toward SR application in clinical populations with sensory loss such as individuals with lower extremity amputation.NEW & NOTEWORTHY Our work showed that cutaneous reflexes, known to be present in response to foot sole stimulation, can also be evoked by stimulation of hairy leg skin. In addition, we demonstrated that adding tactile noise can enhance this reflex response. These findings demonstrate proof-of-concept for potential future applications where tactile stimulation, applied to the leg of an individual with amputation, can enhance postural-relevant reflexes. Improving postural control may reduce the risk of falls in this high-risk population.


Assuntos
Perna (Membro) , Coxa da Perna , Humanos , Perna (Membro)/fisiologia , Músculo Esquelético/fisiologia , Eletromiografia/métodos , Vibração , Estimulação Elétrica/métodos , Reflexo/fisiologia
2.
J Cardiovasc Electrophysiol ; 34(3): 682-692, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36482158

RESUMO

INTRODUCTION: Reliable ex vivo cardiac ablation models have the potential to increase catheter testing throughput while minimizing animal usage. The goal of this work was to develop a physiologically relevant ex vivo swine model of cardiac ablation displaying minimal variability and high repeatability and identify and optimize key parameters involved in ablation outcomes. METHODS AND RESULTS: A root cause analysis was conducted to identify variables affecting ablation outcomes. Parameters associated with the tissue, bath media, and impedance were identified. Variables were defined experimentally and/or from literature sources to best mimic the clinical cardiac ablation setting. The model was validated by performing three independent replicates of ex vivo myocardial ablation and a direct comparison of lesion outcomes of the ex vivo swine myocardial and in vivo canine thigh preparation (TP) models. Replicate experiments on the ex vivo model demonstrated low variance in ablation depth (6.5 ± 0.6, 6.3 ± 0.6, 6.2 ± 0.4 mm) and width (10.4 ± 1.1, 9.7 ± 1.0, 9.9 ± 0.9 mm) and no significant differences between replicates. In a direct comparison of the two models, the ex vivo model demonstrated ablation depths similar to the canine TP model at 35 W (6.9 ± 1.0, and 7.0 ± 0.9 mm) and 50 W (8.0 ± 0.7, and 8.4 ± 0.7 mm), as well as similar power to depth ratios (15% and 19% for the ex vivo cardiac and in vivo TP models, respectively). CONCLUSION: The ex vivo model exhibited strong lesion reproducibility and power-to-depth ratios comparable to the in vivo TP model. The optimized ex vivo model minimizes animal usage with increased throughput, lesion characteristics similar to the in vivo TP model, and ability to discriminate minor variations between different catheter designs.


Assuntos
Ablação por Cateter , Coração , Suínos , Animais , Cães , Reprodutibilidade dos Testes , Miocárdio/patologia , Ablação por Cateter/métodos , Catéteres , Cateteres Cardíacos
3.
J Thromb Thrombolysis ; 54(3): 393-400, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36074227

RESUMO

BACKGROUND: Circadian fluctuations in thrombogenicity and hemostasis play a role in acute cardiovascular thrombotic events occurring in the early morning hours. There is a lack of data assessing thrombogenicity, platelet function, and hemodynamics to investigate diurnal variations in a high cardiovascular risk population. METHODS: This was an exploratory, single-center study conducted in aspirin-treated patients with Type II Diabetes Mellitus (T2DM) (n = 37) with documented vascular disease and/or multiple cardiovascular risk factors. Hemodynamic monitoring and blood sample collection for thromboelastography (TEG) and platelet function testing were done serially at 7-9 AM (morning), 7-9 PM (evening), 11 PM-1 AM (night), and at 5-7 AM (awakening). RESULTS: R-value measured by TEG was shorter during awakening hours than during the night and day hours (p < 0.05). There were no changes in platelet reactivity in response to arachidonic acid, adenosine diphosphate, and collagen between time points. Pulse pressure (PP) was highest during awakening hours (p < 0.05). CONCLUSION: Study findings provide a mechanistic explanation for increased thrombotic events observed in the early waking hours among diabetics with multiple cardiovascular risk factors. The role of chronotherapy in reducing coagulability and PP to improve clinical outcomes should be explored.


Assuntos
Diabetes Mellitus Tipo 2 , Trombose , Difosfato de Adenosina , Ácido Araquidônico , Aspirina , Pressão Sanguínea/fisiologia , Ritmo Circadiano/fisiologia , Diabetes Mellitus Tipo 2/complicações , Humanos , Trombose/etiologia
4.
Anim Biotechnol ; 32(2): 155-168, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31599201

RESUMO

Many contrasting reports are available on generation of bovine induced pluripotent stem cells (iPSCs) employing different timelines and culture conditions which signifies reprogramming process varies between species and cell types. The present study determines an optimum time period required to re-initiate reprogramming events in buffalo fibroblasts after introduction of exogenous genes (OCT4, SOX2, KLF4 and c-MYC) by lentiviral vector. The reprogramming efficiency is cumulative result of many factors including culture conditions and addition of growth factors in culture media. In our study, we observed when stem cell culture conditions were provided Day 5 post-transduction, it results in maximum reprogramming efficiency in comparison when same conditions were provided too early or on later days. The putative iPSCs were expanded on feeder layer for 15 passages and found positive for alkaline phosphatase and pluripotency markers (OCT4, SOX2, KLF4, c-MYC, UTF, TELOMERASE, FOXD3, REX1, STAT3, NUCLEOSTAMIN and TRA1-81). Also, they produced embryoid bodies showing expression for ectodermal (NF68, MOBP), mesodermal (ASA, BMP4) and endodermal (GATA4, AFP) markers to confirm their pluripotent nature. Our results suggest that reprogramming is accompanied by time dependent events and providing stem cell culture conditions at definite time during reprogramming can help in generation of iPSCs with greater efficiency.


Assuntos
Búfalos/embriologia , Meios de Cultura/farmacologia , Feto/citologia , Fibroblastos/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Animais , Técnicas de Cultura de Células , Diferenciação Celular , Fibroblastos/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Células-Tronco Pluripotentes Induzidas/metabolismo , Lentivirus , Fatores de Tempo
5.
J Thromb Thrombolysis ; 49(2): 271-286, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31512202

RESUMO

New guideline recommendations prefer direct oral anticoagulants (DOACs) over warfarin in DOAC-eligible patients with atrial fibrillation and patients with venous thromboembolism. As expected with all antithrombotic agents, there is an associated increased risk of bleeding complications in patients receiving DOACs that can be attributed to the DOAC itself, or other issues such as acute trauma, invasive procedures, or underlying comorbidities. For the majority of severe bleeding events, the widespread approach is to withdraw the DOAC, then provide supportive measures and "watchful waiting" with the expectation that the bleeding event will resolve with time. However, urgent reversal of anticoagulation may be advantageous in patients with serious or life-threatening bleeding or in those requiring urgent surgery or procedures. Until recently, the lack of specific reversal agents, has affected the uptake of these agents in clinical practice despite a safer profile compared to warfarin in clinical trials. In cases of life-threatening or uncontrolled bleeding or when patients require emergency surgery or urgent procedures, idarucizumab has been recently approved for reversal of anticoagulation in dabigatran-treated patients and andexanet alfa for factor Xa inhibitor-treated treated patients. The current review summarizes the current clinical evidence and scope of these agents with the potential impact on DOAC use in clinical practice.


Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Anticoagulantes/administração & dosagem , Coagulação Sanguínea/efeitos dos fármacos , Fator Xa/administração & dosagem , Proteínas Recombinantes/administração & dosagem , Administração Oral , Anticoagulantes/efeitos adversos , Coagulação Sanguínea/fisiologia , Ensaios Clínicos como Assunto/métodos , Hemorragia/induzido quimicamente , Hemorragia/tratamento farmacológico , Humanos
6.
Soft Matter ; 13(36): 6118-6128, 2017 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-28785755

RESUMO

Freeze drying and re-dispersibility of oil-in-water (o/w) emulsions is important from the perspective of storage, transportation and usability. A set of stable and re-dispersible o/w emulsions using polyacryloyl hydrazide (PAHz) capped Ag nanoparticles (NP) as the stabilizer is reported in which the NP size (Davg) and PAHz concentration collectively controlled the stability and re-dispersibility of the emulsion system. O/w emulsions prepared using different concentrations of PAHz (0.05-0.25 g mL-1) and sizes of Ag NPs (10-25 nm) were analyzed by DLS, IFT, contact angle, SEM, and rheological studies. The emulsion stabilized by 0.05 g mL-1 of PAHz and Ag NPs (Davg ≈ 20 nm, 5 wt% PAHz-Ag NPs) was unstable against coalescence, exhibited maximum oil leakage during freeze-drying and lacked re-dispersibility. The stability of the Pickering emulsions was inversely proportional to the Davg of the Ag NPs. The presence of Ag NPs possessing Davg ≈ 10 nm and 0.25 g mL-1 of PAHz in the aqueous phase (25 wt% PAHz-Ag NPs) stabilized the Pickering emulsions for up to 30 days without any sign of creaming and the oil powders (oil content ≈ 98%) obtained after freeze drying exhibited adequate re-dispersibility in aqueous media. In addition, the emulsion stabilized by 25 wt% PAHz-Ag NPs showed maximum recovery of the viscosity value after re-dispersion and exhibited similar shear-thinning behavior to that of the original sample. Furthermore, the trends of moduli vs. frequency for the re-dispersed samples were similar to that of the original samples suggesting that the structural arrangements between Ag NPs and oil droplets were least affected by the drying process. Thus, we conclude that o/w emulsions stabilized by PAHz-Ag NPs can be a potential alternative to produce stable oil powders or gels for industrial applications.

7.
World J Surg Oncol ; 14(1): 283, 2016 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-27835997

RESUMO

BACKGROUND: Primary appendiceal adenocarcinoma is a rare tumor, mucinous variety being common. This case is reported to highlight the unusual presentation and diagnostic difficulty of appendiceal adenocarcinoma. CASE PRESENTATION: Patient presented with acute appendicitis with ill-defined tender lump which responded to conservative management. CONCLUSIONS: High index of suspicion should be kept in mind for elderly patients presenting with appendicular lump. Every effort should be made during elective appendectomy to remove stump in case of sloughed out appendix.


Assuntos
Adenocarcinoma/diagnóstico , Neoplasias do Apêndice/diagnóstico , Apendicite/diagnóstico , Apêndice/patologia , Excisão de Linfonodo , Abscesso Abdominal/diagnóstico por imagem , Abscesso Abdominal/etiologia , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Fatores Etários , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Apendicectomia/métodos , Neoplasias do Apêndice/tratamento farmacológico , Neoplasias do Apêndice/patologia , Neoplasias do Apêndice/cirurgia , Apendicite/complicações , Apendicite/patologia , Apendicite/cirurgia , Apêndice/cirurgia , Antígeno Carcinoembrionário/sangue , Quimioterapia Adjuvante , Colectomia , Diagnóstico Diferencial , Procedimentos Cirúrgicos Eletivos , Feminino , Fluoruracila/uso terapêutico , Humanos , Leucovorina/uso terapêutico , Linfonodos/patologia , Linfonodos/cirurgia , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Compostos Organoplatínicos/uso terapêutico , Doenças Raras/diagnóstico , Tomografia Computadorizada por Raios X , Ultrassonografia
8.
Pain Pract ; 16(7): E99-E102, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27378524

RESUMO

OBJECTIVES: The primary objective of this case report was to demonstrate the therapeutic benefit of stellate ganglion block in trigeminal postherpetic neuralgia. METHODS: This was a case report on a single patient who presented with debilitating photophobia secondary to left-sided trigeminal postherpetic neuralgia. A left-sided stellate ganglion block was performed on the patient under fluoroscopic guidance. The primary endpoints were VAS pain scores and changes in functional capacity. RESULTS: The patient demonstrated significant reduction in her VAS pain score and improved functional capacity for approximately 6 months after the intervention. This case report provides evidence that sympathectomy via a stellate ganglion block can treat photophobia secondary to postherpetic neuralgia in the V1 distribution.


Assuntos
Bloqueio Nervoso Autônomo/métodos , Neuralgia Pós-Herpética/complicações , Fotofobia/etiologia , Fotofobia/cirurgia , Gânglio Estrelado/cirurgia , Neuralgia do Trigêmeo/complicações , Feminino , Herpes Zoster/complicações , Humanos , Medição da Dor
9.
Appl Physiol Nutr Metab ; 49(3): 293-305, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-37913527

RESUMO

There is growing evidence to support a role for the abductor hallucis (AH) in standing balance control; however, functional properties of the muscle that may provide more insight into AH's specific contribution to upright posture have yet to be characterized. This study was conducted to quantify functional neuromechanical properties of the AH and correlate the measures with standing balance variables. We quantified strength and voluntary activation during maximal voluntary isometric contractions of the great toe abductor in nine (3 females and 6 males) healthy, young participants. During electrically evoked twitch and tetanic contractions, we measured great toe abduction peak force and constructed a force-frequency curve. We also evaluated peak abduction force, contraction time (CT), half-relaxation time (HRT), rate of force development (RFD), and relaxation rate (RR) from twitch contractions evoked using doublet stimuli. Strength, VA, CT, HRT, RFD, and RR were correlated to centre of pressure standard deviation (COP SD) and velocity (COP VEL) variables of the traditional COP trace and its rambling and trembling components during single-legged stance. AH twitch properties (e.g., CT: 169.8 ± 32.3 ms; HRT: 124.1 ± 29.2 ms) and force-frequency curve were similar to other slow contractile muscles. Contractile speed related negatively with COP VEL, suggesting AH may be appropriate for slow, prolonged tasks such as ongoing postural balance control. Correlation coefficient outcomes for all variables were similar between rambling and trembling components. Our results provide further evidence for the importance of AH neuromechanical function for standing balance control, at least during a challenging single-legged posture.


Assuntos
, Músculo Esquelético , Masculino , Feminino , Humanos , Pé/fisiologia , Músculo Esquelético/fisiologia , Contração Muscular/fisiologia , Postura/fisiologia , Equilíbrio Postural/fisiologia
10.
Circ Arrhythm Electrophysiol ; 17(4): e012717, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38390748

RESUMO

BACKGROUND: The effect of contact force (CF) on lesion formation is not clear during pulsed field ablation (PFA). The aim of this study was to evaluate the impact of CF, PFA, and their interplay through the PFA index (PF index) formula on the ventricular lesion size in swine. METHODS: PFA was delivered through the CF-sensing OMNYPULSE catheter. Predefined PFA applications (×3, ×6, ×9, and ×12) were delivered maintaining low (5-25 g), high (26-50 g), and very high (51-80 g) CFs. First, PFA lesions were evaluated on necropsy in 11 swine to investigate the impact of CF/PFA-and their integration in the PF index equation-on lesion size (study characterization). Then, 3 different PF index thresholds-300, 450, and 600-were tested in 6 swine to appraise the PF index accuracy to predict the ventricular lesion depth (study validation). RESULTS: In the study characterization data set, 111 PFA lesions were analyzed. CF was 32±17 g. The average lesion depth and width were 3.5±1.2 and 12.0±3.5 mm, respectively. More than CF and PFA dose alone, it was their combined effect to impact lesion depth through an asymptotically increasing relationship. Likewise, not only was the PF index related to lesion depth in the study validation data set (r2=0.66; P<0.001) but it also provided a prediction accuracy of the observed depth of ±2 mm in 69/73 lesions (95%). CONCLUSIONS: CF and PFA applications play a key role in lesion formation during PFA. Further studies are required to evaluate the best PFA ablation settings to achieve transmural lesions.


Assuntos
Ablação por Cateter , Suínos , Animais , Ablação por Cateter/efeitos adversos , Ventrículos do Coração/cirurgia , Catéteres , Desenho de Equipamento
11.
Environ Sci Pollut Res Int ; 30(11): 31231-31241, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36445523

RESUMO

This study investigates the role of single-step silica nanofluids as additives to increase CO2 absorption in polymeric solutions for proposed oilfield applications. Using pressure decay approach, the study investigates the applicability of single-step silica nanofluids for CO2 absorption in a high pressure-high temperature (HPHT) cell. Various parameters like nanoparticle size (30-120 nm) and concentration (0.1-1 wt%) were investigated to ascertain the absorption performance of the nanofluids and optimization their application in subsurface applications as carrier fluids for CO2. The solutions under observation (deionized water and silica nanofluids) were pressurized under the desired pressure and temperature inside a stirring pot and the decline in pressure was continuously noted. To comprehensively cover the near-reservoir field conditions, the CO2 absorption was investigated in the pressure range of 5-10 MPa and at temperatures of 30-90 °C. While increasing the nanoparticle concentration (from 0.1 to 1 wt%) increased the CO2 absorption (evident by the sharper decline in pressure), increasing the nanoparticle size reduced the absorption capacity of the nanofluids as a lesser volume of decline in pressure was noted. Furthermore, increasing the temperature of the experimental investigation caused a major reduction (12-19%) in the pressure decay. However, it was also observed that higher pressure (> 7.5 MPa) was detrimental for CO2 absorption (due to its supercritical nature). Adding salt (sodium chloride, NaCl) was found to massively lower (up to 33%) while adding surfactant (sodium dodecyl sulfate, SDS) slightly increased the amount of CO2 absorption (in presence of salinity). Based on the observations of this study, the use of single-step silica nanofluids as CO2 carrier fluids is recommended for oilfield conditions where salinity is less than 4 wt%.


Assuntos
Dióxido de Carbono , Nanopartículas , Dióxido de Silício , Difusão , Tensoativos
12.
Tex Heart Inst J ; 50(2)2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-37011365

RESUMO

A 55-year-old man presented with chest pain and was diagnosed with non-ST-segment elevation myocardial infarction. Coronary angiography revealed a 95% eccentric lesion in the mid-right coronary artery. After 3 intracoronary stents were placed, the guidewire became entrapped in 1 of the stents; multiple attempts at retrieval were unsuccessful. Ultimately, the guidewire fractured, and a coronary artery bypass graft surgery was performed to remove the guidewire fragments. This report reviews the procedural steps for wire retrieval that are critical for operators to avoid coronary artery bypass surgery.


Assuntos
Angioplastia Coronária com Balão , Intervenção Coronária Percutânea , Masculino , Humanos , Pessoa de Meia-Idade , Angioplastia Coronária com Balão/efeitos adversos , Intervenção Coronária Percutânea/efeitos adversos , Ponte de Artéria Coronária/efeitos adversos , Angiografia Coronária , Vasos Coronários , Stents , Resultado do Tratamento
13.
J Appl Physiol (1985) ; 135(5): 985-994, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37675471

RESUMO

Cutaneous input is important in postural control and balance. Aging and diabetes impair skin sensitivity and motor control. Heat application can improve skin sensation, but its influence on motor control remains unknown. This study investigated the effects of heating the skin of the foot sole on lower limb cutaneous reflexes. Reflexes were evoked in the tibialis anterior muscle of 20 young, healthy adults before and after heating the foot sole to a maximum of 42°C. While holding a 15% maximum root mean square EMG generated during maximum isometric dorsiflexion, a filtered white noise (0-50 Hz) vibration at 10 times the perceptual threshold was applied to the heel to stimulate cutaneous mechanoreceptors. Reflexes were analyzed in both the time (cumulant density) and frequency (coherence, gain) domains. Heat increased foot skin temperature ∼15.4°C (P < 0.001). Cumulant density peak to peak amplitude significantly increased by 44% after heating (P = 0.01) while latencies did not vary (P = 0.46). Coherence and gain were significantly greater in the 30- to 40-Hz range following heating (P = 0.048; P = 0.02). Heating significantly enhances lower limb cutaneous reflexes. This may be due to the increased ability of cutaneous mechanoreceptors to encode in the 30- to 40-Hz range.NEW & NOTEWORTHY Cutaneous input is a known modulator of muscle activity. Targeting skin to intentionally enhance motor output has received little attention. We explored local skin heating to enhance skin sensitivity and found a significant increase in the amplitude, coherence, and gain of cutaneous reflexes in the tibialis anterior. Our current findings provide the first support for the use of heat as a viable and easily integrated modality in rehabilitation technology to improve balance and postural control.


Assuntos
, Calefação , Humanos , Adulto , Pé/fisiologia , Extremidade Inferior , Pele , Reflexo/fisiologia , Músculo Esquelético/fisiologia , Eletromiografia , Estimulação Elétrica
14.
Indian J Ophthalmol ; 71(7): 2711-2716, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37417109

RESUMO

Purpose: To identify the facial anthropometric parameters that predict the difficulty during femtosecond (FS) laser. Methods: This was a: single-center observational study was conducted on participants between the ages 18 and 30 years who were planned for FS-LASIK (femtosecond laser-assisted laser in situ keratomileusis) or SMILE (small incision lenticule extraction) at Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi, India. The front and side-facing images of the participants were analyzed using Image J software to measure different anthropometric parameters. The nasal bridge index, facial convexity, and other parameters were measured. The difficulty faced by the surgeon during docking was recorded for each subject. The data were analyzed on Stata 14. Results: A total of 97 subjects were included. The mean age was 24 (±7) years. Twenty-three (23.71%) subjects were females while the rest were males. Difficulty in docking was seen in 1 (4.34%) female and 14 (19%) males. The mean nasal bridge index was 92.58 (±4.01) in subjects with deep-set eyes and 89.72 (±4.30) in normal subjects. The mean total facial convexity was 129.28 (±4.24) in deep-set eyes, and 140.23 (±4.74) in normal subjects. Conclusion: Total facial convexity appeared as the most important feature, with the value being less than 133° in most subjects with unfavorable facial anthropometry.


Assuntos
Ceratomileuse Assistida por Excimer Laser In Situ , Miopia , Masculino , Humanos , Feminino , Adolescente , Adulto Jovem , Adulto , Córnea , Substância Própria/cirurgia , Acuidade Visual , Lasers de Excimer , Miopia/cirurgia , Estudos Prospectivos , Ceratomileuse Assistida por Excimer Laser In Situ/métodos
15.
Circ Arrhythm Electrophysiol ; 16(12): 663-671, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37994554

RESUMO

BACKGROUND: Pulsed field ablation (PFA) has emerged as an alternative to radiofrequency ablation. However, data on focal point-by-point PFA are scarce. The aim of this study was to compare lesion durability and collateral damage between focally delivered unipolar/biphasic PFA versus radiofrequency in swine. METHODS: Eighteen swine were randomized to low-dose PFA, high-dose PFA, and radiofrequency using a multimodality generator. Radiofrequency delivered by market-available generator served as control group. A contact force-sensing catheter was used to focally deliver PFA/radiofrequency at the pulmonary veins and other predefined sites in the atria. Animals were remapped postprocedurally and 28 days postablation to test lesion durability followed by gross necroscopy and histology. RESULTS: All targeted sites were successfully ablated (contact force value, 13.9±4.1 g). Follow-up remapping showed persistent pulmonary vein isolation in all animals (100%) with lesion durability at nonpulmonary vein sites proven in most (98%). Regardless of the energy source used, the lesion size was similar across the study groups. Transmurality was achieved in 95% of targeted sites and 100% at pulmonary veins. On histology, PFA animals showed more mature scar formation than their radiofrequency counterpart without myocardial necrosis or inflammation. Finally, no sign of collateral damage was observed in any of the groups. CONCLUSIONS: In a randomized preclinical study, focally delivered unipolar/biphasic PFA guided by contact force values was associated with durable lesions on chronic remapping and with mature scar formation on histology without signs of collateral injury on necroscopy. Further studies are needed to investigate the long-term feasibility of this new approach to atrial fibrillation treatment.


Assuntos
Fibrilação Atrial , Ablação por Cateter , Veias Pulmonares , Ablação por Radiofrequência , Animais , Catéteres , Cicatriz , Suínos , Resultado do Tratamento
16.
Environ Sci Pollut Res Int ; 29(27): 41788-41803, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35099700

RESUMO

Modern oil reservoirs exhibit high macro-scale heterogeneity, i.e., presence of shales and clays, which complicate the implementation of conventional enhanced oil recovery (EOR) practices. Hence, there is a need to investigate new class of EOR methods which not only improve recovery of oil from reservoir but also reduce formation damage. Thus, in this study, synthetic smart brines of varying salinity were formulated to investigate carbon utilization in shaly-sandstone for oil recovery and sequestration applications. To prepare shaly-sandstone samples, shale content in sand varied between 0 and 25 wt%. The addition of shale reduced porosity and permeability of sand-packs, and porosity ~ 25 and permeability < 10 md were measured for a combination of 75% sand + 25% shale which were originally 38% and 692 md for 100% sand + 0% shale. The oil recovery experiments were performed at temperature ≈ 40 °C and ambient pressure. The impact of shale content was insignificant on CO2-based oil recovery resulting its value remained nearly constant (5-7%). Smart saline water (SSW) solutions were prepared through the dilution of formation water (FW) of typical oilfield salinity and used these SSW solutions in investigating shale swelling and interfacial tension with CO2. Compared to other SSW solutions, SSW-2 (1 part FW/9 part water: 1/10th of FW) demonstrated superior control on mitigating shale swelling (by 67%) and reduce interfacial tension (by 30%) when compared to FW. Moreover, it helped to mobilize higher amount of oil (50% OOIP) from sand-pack (80% sand + 20% shale) in which conventional water flood failed to perform, indicating its viability for EOR from heterogeneous reservoir. In addition, SSW solutions promoted use of carbonated (CO2-enriched) water injection for oil recovery from sandstone exhibiting high shale content of 20% as over 5-8% higher oil recovery was obtained compared to conventional water flooding. Comparative performance of water flooding, salinity water-alternating CO2 flooding and carbonated smart water injection in heterogeneous sandstone.


Assuntos
Dióxido de Carbono , Inundações , Dióxido de Carbono/análise , Minerais , Campos de Petróleo e Gás , Areia
17.
J Interv Card Electrophysiol ; 64(3): 649-660, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34981289

RESUMO

PURPOSE: Effective identification of electrical drivers within remodeled tissue is a key for improving ablation treatment for atrial fibrillation. We have developed a mutual information, graph-based approach to identify and propose fault tolerance metric of local efficiency as a distinguishing feature of rotational activation and remodeled atrial tissue. METHODS: Voltage data were extracted from atrial tissue simulations (2D Karma, 3D physiological, and the Multiscale Cardiac Simulation Framework (MSCSF)) using multi-spline open and parallel regional mapping catheter geometries. Graphs were generated based on varied mutual information thresholds between electrode pairs and the local efficiency for each graph was calculated. RESULTS: High-resolution mapping catheter geometries can distinguish between rotational and irregular activation patterns using the derivative of local efficiency as a function of increasing mutual information threshold. The derivative is decreased for rotational activation patterns comparing to irregular activations in both a simplified 2D model (0.0017 ± 1 × 10-4 vs. 0.0032 ± 1 × 10-4, p < 0.01) and a more realistic 3D model (0.00092 ± 5 × 10-5 vs. 0.0014 ± 4 × 10-5, p < 0.01). Average local efficiency derivative can also distinguish between degrees of remodeling. Simulations using the MSCSF model, with 10 vs. 90% remodeling, display distinct derivatives in the grid design parallel spline catheter configuration (0.0015 ± 5 × 10-5 vs. 0.0019 ± 6 × 10-5, p < 0.01) and the flower shaped open spline configuration (0.0011 ± 5 × 10-5 vs. 0.0016 ± 4 × 10-5, p < 0.01). CONCLUSION: A decreased derivative of local efficiency characterizes rotational activation and varies with atrial remodeling. This suggests a distinct communication pattern in cardiac rotational activation detectable via high-resolution regional mapping and could enable identification of electrical drivers for targeted ablation.


Assuntos
Fibrilação Atrial , Remodelamento Atrial , Ablação por Cateter , Fibrilação Atrial/cirurgia , Átrios do Coração/cirurgia , Humanos , Serviços de Informação
18.
Mater Today Proc ; 56: 3740-3746, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35070729

RESUMO

The covid-19 pandemic has created problems in every manufacturing sector and has posed considerable challenges to pharmaceutical, healthcare, and sanitation companies. The challenges faced are particularly daunting for pharmaceutical companies producing vaccines with ever-growing demand and shorter and shorter deadlines to fulfill them. Further, due to the vaccine's novelty and unprecedented demand, there is a lack of any available data on which traditional forecasting methods can be used. In this paper, we attempt to propose a solution by utilizing the Grey Systems Theory, particularly the AGM (1, 1) model, which has been used to significant effect for problems involving uncertain / lack of data to forecast the demand for vaccines. The experimental results obtained showed that our proposed model successfully generated accurate forecasts with a small dataset and minimal error. Additionally, judgmental forecasting has been used to qualitatively assess the future scope of vaccine manufacturing as well as the use cases of the model. We can thus effectively say proposed AGM (1,1) model is a lucid method to forecast the demand for vaccines.

19.
Circ Arrhythm Electrophysiol ; 15(7): e010661, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35763432

RESUMO

BACKGROUND: Pulsed-field ablation (PFA) is a tissue-selective, nonthermal cardiac ablation modality. A novel PFA ablation system consisted of a multichannel irreversible electroporation generator system and a multielectrode circular irreversible electroporation catheter has been developed for catheter ablation. To understand the progression and immediate impacts of PFA, this study evaluated the subchronic (7±3 day) and chronic (30±3 day) safety and performance of the novel PFA system when simulating pulmonary vein and superior vena cava isolation in a porcine beating heart model. METHODS: Ten swine models were divided into subchronic (n=6) and chronic cohorts (n=4). Lesions were performed within the right and left atrium to conduct right pulmonary veins and superior vena cava isolations, in addition to creating stacked lesions in the left atrium roof and right atrium posterior wall. RESULTS: Acute pulmonary vein and superior vena cava isolation were achieved in 10 out of 10 swine and demonstrated 100% lesion durability in both cohorts, including sustained elimination of electrical activity at the left atrium roof and right atrium posterior wall. Histology demonstrated that all the cardiac sites ablated showed discrete zones of loss of myocardial fibers or smooth muscle cells with preservation of the tissue architecture with resultant fibrocellular replacement, neovascularization, and neocollagen deposition. Mineralization findings were present in association with residual necrotic muscle fibers. Only in 7 days group, areas of mineralization were frequently associated with inflammation. There were no treatment-related changes in other tissues, including complete sparing of the phrenic nerve. CONCLUSIONS: Pulsed-field ablation for pulmonary vein and superior vena cava isolation with the novel PFA system was feasible, safe with myocardial-specific ablative effect. Durable lesions were observed at the target areas. with inflammation phenomena mainly documented at 7 days.


Assuntos
Fibrilação Atrial , Ablação por Cateter , Veias Pulmonares , Animais , Fibrilação Atrial/cirurgia , Ablação por Cateter/efeitos adversos , Eletroporação , Seguimentos , Inflamação , Veias Pulmonares/patologia , Veias Pulmonares/cirurgia , Suínos , Veia Cava Superior/patologia , Veia Cava Superior/cirurgia
20.
Cornea ; 41(12): 1559-1563, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36197341

RESUMO

PURPOSE: The aim of this study was to analyze the presence of the SARS-CoV-2 virus in the corneal tissue of asymptomatic deceased novel coronavirus disease 2019 (COVID-19) patients. METHODS: This was a cross-sectional study performed at a tertiary eye hospital. All corneas of the deceased asymptomatic donors who tested positive for SARS-CoV-2 on a nasopharyngeal swab at the time of corneal tissue harvesting were included in the study. Histopathological examination and immunohistochemistry were performed. mRNA in situ hybridization for SARS-CoV-2 was performed in all specimens that showed positive immunostaining. The main outcome measure was the presence of SARS-CoV-2 virus in the corneal tissues. RESULTS: Twenty-two corneal tissues of 11 donors were analyzed. The mean age was 72.2 ± 14.2 years. On histological examination, no signs of inflammation or any other abnormalities were detected in the cornea and adjacent bulbar conjunctiva. Immunohistochemistry revealed faint to moderate cytoplasmic staining in the basal layer of the corneal epithelium in 8 specimens from 5 patients. None of the specimens with positive immunostaining showed the presence of SARS-CoV-2 mRNA. CONCLUSIONS: In line with previous studies , our study also reflects the absence of SARS-CoV-2 viral mRNA in corneal tissues of clinically asymptomatic deceased COVID-19 donors, thereby indicating a probable low risk of transmission of the SARS-CoV-2 virus through the transplantation of corneas from donors who tested positive for, but were asymptomatic for COVID-19. In addition, further studies on the subject should include histopathological examination because of the false positive and negative rates of molecular tests.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , COVID-19/diagnóstico , Estudos Transversais , Doadores de Tecidos , Córnea , RNA Mensageiro/genética
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