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1.
Cureus ; 16(3): e55725, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38586644

RESUMO

OBJECTIVE: This retrospective (matched paired) clinical trial aimed to compare the efficacy of dexamethasone vs. methylprednisolone at equipotent (high) doses in patients with coronavirus disease 2019 (COVID-19)-associated acute respiratory distress syndrome (ARDS). METHODS: A total of 347 patients with moderate and severe COVID-19-associated ARDS were administered either a high (equipotent) dose of dexamethasone (32 mg) or methylprednisolone (180 mg) for a duration of up to 10 days. All participants received the standard of care for critically ill COVID-19 patients. RESULTS: The primary outcomes included length of stay in the ICU, ICU mortality, and discharge from the hospital. Based on the obtained results, a tendency towards more favorable clinical outcomes concerning the length of stay in the ICU (in the group of patients treated with non-invasive mechanical ventilation (NIV), p<0.05), ICU mortality, and discharge from the hospital (in the group of patients who were intubated, p<0.05) in patients receiving the high dose of dexamethasone compared to those receiving methylprednisolone was observed. CONCLUSION: It appears that severe cases of COVID-19, especially intubated ones, treated with high doses of dexamethasone have a more favorable clinical outcome than the use of equipotent doses of methylprednisolone. However, larger multicenter studies are needed to validate our observations.

2.
Braz. j. biol ; 842024.
Artigo em Inglês | LILACS-Express | LILACS, VETINDEX | ID: biblio-1469269

RESUMO

Abstract The current focus is on the overall pattern of seed storage present in the fragments of the soil of piedmont and alluvial landscapes of the environment. The present study predicted the seed banks of both soils of alluvial and piedmont zones in different ecological conditions and evaluate the potential of seeds in the restoration of both environments. The composition of the seed bank of soil is mainly affected by the alluvial environment and the structure of cleared area shows that more species of germinating annual grasses and growable seeds with the higher total number. Extant vegetation structures have an important role in the diversity of soil seed reservoirs, whose composition corresponded with the openness of the site. When in situ soil seed bank is recruited, it helps to restore only some components of the plant community in an alluvial environment. In our current research, it was confirmed that seed richness was higher in number at lower elevation (alluvial) than that at high elevation (piedmont). Seed richness showed a significant negative correlation with anions, cations, while significantly positive with altitude that suggests the richness pattern of the overall seed bank of the area is influenced by various environmental factors.


Resumo O foco atual está no padrão geral de armazenamento de sementes presente nos fragmentos de solo do Piemonte e nas paisagens aluviais do meio ambiente. O presente estudo previu os bancos de sementes de ambos os solos das zonas aluvial e piemontesa em diferentes condições ecológicas e avaliou o potencial das sementes na restauração de ambos os ambientes. A composição do banco de sementes do solo é afetada principalmente pelo ambiente aluvial e a estrutura da área desmatada mostra que mais espécies de gramíneas anuais em germinação e sementes cultiváveis apresentam o maior número total. As estruturas da vegetação existente têm um papel importante na diversidade dos reservatórios de sementes do solo, cuja composição correspondeu à abertura do local. Quando o banco de sementes do solo in situ é recrutado, o mesmo ajuda a restaurar apenas alguns componentes da comunidade de plantas em um ambiente aluvial. Em nossa pesquisa atual, foi confirmado que a riqueza de sementes era maior em número em altitudes mais baixas (aluviais) do que em altitudes elevadas (Piemonte). A riqueza de sementes mostrou uma correlação negativa significativa com ânions, cátions, enquanto significativamente positiva com a altitude, o que sugere que o padrão de riqueza do banco geral de sementes da área é influenciado por vários fatores ambientais.

3.
Braz. j. biol ; 84: e255485, 2024. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1350312

RESUMO

Abstract The current focus is on the overall pattern of seed storage present in the fragments of the soil of piedmont and alluvial landscapes of the environment. The present study predicted the seed banks of both soils of alluvial and piedmont zones in different ecological conditions and evaluate the potential of seeds in the restoration of both environments. The composition of the seed bank of soil is mainly affected by the alluvial environment and the structure of cleared area shows that more species of germinating annual grasses and growable seeds with the higher total number. Extant vegetation structures have an important role in the diversity of soil seed reservoirs, whose composition corresponded with the openness of the site. When in situ soil seed bank is recruited, it helps to restore only some components of the plant community in an alluvial environment. In our current research, it was confirmed that seed richness was higher in number at lower elevation (alluvial) than that at high elevation (piedmont). Seed richness showed a significant negative correlation with anions, cations, while significantly positive with altitude that suggests the richness pattern of the overall seed bank of the area is influenced by various environmental factors.


Resumo O foco atual está no padrão geral de armazenamento de sementes presente nos fragmentos de solo do Piemonte e nas paisagens aluviais do meio ambiente. O presente estudo previu os bancos de sementes de ambos os solos das zonas aluvial e piemontesa em diferentes condições ecológicas e avaliou o potencial das sementes na restauração de ambos os ambientes. A composição do banco de sementes do solo é afetada principalmente pelo ambiente aluvial e a estrutura da área desmatada mostra que mais espécies de gramíneas anuais em germinação e sementes cultiváveis ​​apresentam o maior número total. As estruturas da vegetação existente têm um papel importante na diversidade dos reservatórios de sementes do solo, cuja composição correspondeu à abertura do local. Quando o banco de sementes do solo in situ é recrutado, o mesmo ajuda a restaurar apenas alguns componentes da comunidade de plantas em um ambiente aluvial. Em nossa pesquisa atual, foi confirmado que a riqueza de sementes era maior em número em altitudes mais baixas (aluviais) do que em altitudes elevadas (Piemonte). A riqueza de sementes mostrou uma correlação negativa significativa com ânions, cátions, enquanto significativamente positiva com a altitude, o que sugere que o padrão de riqueza do banco geral de sementes da área é influenciado por vários fatores ambientais.


Assuntos
Solo , Banco de Sementes , Paquistão , Plantas , Sementes , Ecossistema , Poaceae
4.
Cureus ; 15(7): e41422, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37546147

RESUMO

Background Opioid-induced constipation (OIC) has become more common in the intensive care unit (ICU) due to increased opioid utilization. Traditional laxatives often prove ineffective against OIC, leading to the increased utilization of naloxegol. However, further research is needed to confirm naloxegol's effectiveness and safety in critical care. This study aimed to explore the safety and efficacy of this intervention in critically ill OIC patients. Methods A single-center retrospective study was conducted on 353 patients who received one or more doses of naloxegol from January 1, 2019, to June 30, 2020, for OIC at a tertiary care center. The primary endpoint of this study was to evaluate serious adverse events such as reduced analgesic effect, gastrointestinal perforation, seizure, acute myocardial infarction (AMI), or ventricular arrhythmias using Naranjo Scale in critically ill patients. The secondary goal was to assess the efficacy of naloxegol, measured by the time of the first bowel movement. Results The average duration of naloxegol use was three days, with the first bowel movement occurring at an average of 11.3 hours. Furthermore, 59.8% of individuals had their first bowel movement within 20 hours of receiving naloxegol. There was a low level of causality between naloxegol use and adverse events such as gastrointestinal perforation, seizures, AMI, cardiovascular mortality, stroke, and ventricular arrhythmia. Additionally, reduction in analgesia showed no strong relationship with naloxegol use indicated by the Naranjo Scale assessment. Conclusion Naloxegol showed promising safety and efficacy profiles in treating OIC amongst critically ill patients, though our findings require further validation through prospective studies. This research paves the way for further investigation into naloxegol's role in OIC management, emphasizing the necessity of personalized treatment strategies in critical care settings.

5.
J Oral Maxillofac Pathol ; 27(1): 173-180, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37234328

RESUMO

Background: Gingival lesions in oral lichen planus can indirectly increase the risk of plaque-induced periodontal disease when symptoms associated with such lesions hamper the proper oral hygiene maintenance by the patients and can increase the risk of periodontal tissue destruction. This systematic review analyses the existing evidence on the association between oral lichen planus and periodontal disease. Aim: This systematic review of case-control studies aimed to analyse the association between periodontal disease and oral lichen planus. Material and Methods: An electronic database search for randomised controlled trials, experimental studies, case-control studies, and cohort studies published in peer-reviewed Journals in the English language was conducted from the following databases: PubMed, EBSCOHost, Science Open, EMBASE, and Google Scholar. Results: A total of 12,507 were identified on an electronic database search. Only eight studies fulfilled the eligibility criteria and were included for quantitative analysis. A data extraction sheet was prepared, and studies were analysed. Conclusion: Bleeding on Probing and Probing depth were seen to be significantly associated with Oral Lichen Planus. The symptoms in Oral Lichen Planus impede efficient oral hygiene maintenance by a patient and predispose them to the occurrence of long-term Periodontal Disease.

6.
J Oral Maxillofac Pathol ; 26(3): 422, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36588843

RESUMO

Background: Melanin is the predominant pigment responsible for the color of skin, hair, iris of eyes, and oral mucosa. Tyrosinase (TYR) is the key enzyme involved in melanin synthesis. Studies in dermatology have shown a positive correlation between TYR enzyme levels and melanin pigmentation of the skin. However, no study has been conducted to assess TYR levels in the gingiva. Hence the present study was conducted to assess TYR levels in gingival melanin hyperpigmentation. Aim: To assess the TYR gene expression in gingiva in individuals with moderate to severe gingival melanin hyperpigmentation. Methodology: Subjects with a chief complaint of blackish appearance of gums with an unesthetic smile were included in the study. Informed consent was obtained. Scaling and root planning were done and subjects were recalled after 2 weeks. The gingival depigmentation procedure was performed using the conventional scalpel technique under adequate local anesthesia. The selected sites underwent conventional gingival depigmentation technique using Bard-Parker handle no: 3 and blade no: 11. The excised layer of epithelium along with a thin layer of underlying connective was sent to the laboratory to assess the TYR gene expression by real-time polymerase chain reaction technique. Results: The levels of the TYR enzyme activity in the gingival tissues from the selected sites were assessed. Table 1 and Graph 1 show the levels of TYR enzyme gene expression in the gingival tissue. Conclusion: TYR gene expression and the degree of gingival melanin hyperpigmentation are positively correlated. Hence the assessment of TYR enzyme activity in gingiva could be of great value in today's cosmetologically conscious individuals.

7.
Braz J Biol ; 84: e255485, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34878007

RESUMO

The current focus is on the overall pattern of seed storage present in the fragments of the soil of piedmont and alluvial landscapes of the environment. The present study predicted the seed banks of both soils of alluvial and piedmont zones in different ecological conditions and evaluate the potential of seeds in the restoration of both environments. The composition of the seed bank of soil is mainly affected by the alluvial environment and the structure of cleared area shows that more species of germinating annual grasses and growable seeds with the higher total number. Extant vegetation structures have an important role in the diversity of soil seed reservoirs, whose composition corresponded with the openness of the site. When in situ soil seed bank is recruited, it helps to restore only some components of the plant community in an alluvial environment. In our current research, it was confirmed that seed richness was higher in number at lower elevation (alluvial) than that at high elevation (piedmont). Seed richness showed a significant negative correlation with anions, cations, while significantly positive with altitude that suggests the richness pattern of the overall seed bank of the area is influenced by various environmental factors.


Assuntos
Banco de Sementes , Solo , Ecossistema , Paquistão , Plantas , Poaceae , Sementes
8.
J Nanosci Nanotechnol ; 21(6): 3573-3579, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34739809

RESUMO

High demand of food for rapidly increasing population requires novel but ecofriendly fertilizers. Green reducing and capping agents are being explored to minimize production cost and toxicity of chemicals in synthesis of nanoparticles (NPs) which could be used to increase the production of crops and plants. In present research, Zinc Oxide Nanoparticles (ZnO NPs) are produced by employing an eco-friendly, simple and efficient green route using peel extract of Citrus reticulate. The optical properties of green synthesized ZnO NPs are explored by UV-Visible and Photoluminance spectroscopies where NPs presented 3.21 to 3.13 eV band gap. The morphology and purity of the ZnO NPs are analyzed by scanning electron microscopy (SEM), X-ray diffraction technique (XRD) and energy dispersive X-ray spectroscopy (EDX), respectively. The spherical like ZnO NPs having 23-90 nm size exhibited hexagonal structure with 8.89 to 8.62 nm crystallite size. Fourier transform infrared spectroscopy (FTIR) explores the existence of specific functional groups which are responsible for stabilization, capping and reduction during synthesis of nanoparticles. The green synthesized ZnO NPs are tested for seed germination of Brassica nigra (black mustard) seeds at standard temperature and pressure. The activity shows that germination percentage of the Brassica nigra seeds is enhanced 100% and seedling vigor index 16.45 after treatment with ZnO NPs and can be controlled by the concentration of NPs. Therefore, it can be expected that ZnO NPs can serve as the cost effective and ecofriendly nano-fertilizers in agriculture.


Assuntos
Citrus , Nanopartículas Metálicas , Óxido de Zinco , Antibacterianos , Germinação , Química Verde , Mostardeira , Extratos Vegetais , Sementes , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
9.
Acta Biomater ; 134: 302-312, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34311104

RESUMO

Oxidative stability of radiation crosslinked ultrahigh molecular weight polyethylene (UHMWPE) artificial joints is significantly improved by vitamin E (VE), but there is a dilemma that VE hinders crosslinking and thus jeopardizes the wear of UHMWPE. In this effort, we proposed an efficient strategy to stabilize UHMWPE under limited antioxidant contents, where VE and D-sorbitol (DS) were used as the primary antioxidant and the secondary antioxidant respectively. For non-irradiated blends with fixed antioxidant contents, oxidative stability accessed by oxidation induction time (OIT) of VE/DS/UHMWPE blends was superior to that of VE/UHMWPE blends, while DS/UHMWPE blends showed no increase in OIT. The cooperation between DS and VE exhibited a synergistic effect on enhancing the oxidative stability of UHMWPE. Interestingly, the irradiated VE/DS/UHMWPE blends showed comparable OIT but a significantly higher crosslink density than the irradiated VE/UHMWPE blends. The crystallinity, melting point, and in vitro biocompatibility of the blends were not affected by VE and DS. The quantitative relationships of mechanical properties, oxidation stability, crystallinity and crosslink density were established to unveil the correlation of these key factors. The overall properties of VE/UHMWPE and VE/DS/UHMWPE blends were compared to elucidate the superiority of the antioxidant compounding strategy. These findings provide a paradigm to break the trade-off between oxidative stability, crosslink density and mechanical properties, which is constructive to develop UHMWPE bearings with upgraded performance for total joint replacements. STATEMENT OF SIGNIFICANCE: VE-stabilized UHMWPE is the most commonly used material in total joint replacements at present. However, oxidation and wear resistance of VE/UHMWPE implants cannot be unified since VE reduces the efficiency of radiation crosslinking. It limits the use of VE. Herein, we proposed a compounding stabilization by the synergy between VE and DS. The antioxidation capability of VE was revived by DS, thus enhancing the oxidation stability of unirradiated UHMWPE. The irradiated VE/DS/UHMWPE exhibited similar oxidation stability but higher crosslink density than irradiated VE/UHMWPE, which is beneficial to combat wear of UHMWPE and to inhibit the occurrence of osteolysis. This synergistic antioxidation strategy endows the UHMWPE joint material with good overall performance, which is of clinical significance.


Assuntos
Polietilenos , Vitamina E , Teste de Materiais , Peso Molecular , Sorbitol , Vitamina E/farmacologia
10.
Mater Sci Eng C Mater Biol Appl ; 124: 112040, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33947540

RESUMO

To avoid catastrophic bacterial infection in prosthesis failure, ultrahigh molecular weight polyethylene (UHMWPE), a common bearing material of artificial joints, has been formulated with antibiotics to eliminate bacteria locally at the implant site. However, the pressing issues regarding cytotoxic effects and evolution of drug resistant bacteria necessitates the development of bio-friendly bacteriostat with long bacteriostatic efficacy. Herein, tea polyphenol extracted from nature source was introduced in UHMWPE as a biogenic antimicrobial. Controlled antimicrobial activity was achieved by chemical crosslinking to regulate the release of the tea polyphenol. In addition, the crosslinking efficiency of UHMWPE blends with high loaded tea polyphenol was significantly improved in comparison to radiation crosslinking. The immobilized tea polyphenols also enhanced the oxidation stability of the UHMWPE, which is essential to prolong the service life in vivo and the storage time in vitro. The blends presented good biocompatibility, despite cell repellent on the highly crosslinked surface. Chemically crosslinked tea polyphenol/UHMWPE exhibited feasible properties for total joint implants, which is promising for clinical application.


Assuntos
Artroplastia de Substituição , Polifenóis , Teste de Materiais , Peso Molecular , Polietilenos , Polifenóis/farmacologia , Chá , Tiram
11.
ACS Biomater Sci Eng ; 7(1): 373-381, 2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33351587

RESUMO

Highly crosslinked ultrahigh-molecular-weight polyethylene (UHMWPE) bearings are wear-resistant to reduce aseptic loosening but are susceptible to oxidize in vivo/in vitro, as reported in clinical studies. Despite widespread acceptance of antioxidants in preventing oxidation, the crosslinking efficiency of UHMWPE is severely impacted by antioxidants, the use of which was trapped in a trace amount. Herein, we proposed a new strategy of polyphenol-assisted chemical crosslinking to facilitate the formation of a crosslinking network in high-loaded tea polyphenol/UHMWPE blends. Epigallocatechin gallate (EGCG), a representative of tea polyphenol, was mixed with UHMWPE and peroxide. Multiple reactive phenolic hydroxyl groups of tea polyphenol coupled with the nearby free radicals to form extra crosslinking sites. The crosslinking efficiency was remarkably enhanced with increasing tea polyphenol content, even at a concentration of 8 wt %. Given by the hydrogen donation principle, the high-loaded tea polyphenol also enhanced the oxidation stability of the crosslinked UHMWPE. The antioxidative performance was preserved even after tea polyphenol elution. Moreover, superior antibacterial performance was achieved by the in situ tea polyphenol release from the interconnected pathways in the present design. The strategy of polyphenol-assisted chemical crosslinking is applicable for producing highly crosslinked, antioxidative, and antibacterial UHMWPE, which has promising prospects in clinical applications.


Assuntos
Antioxidantes , Artroplastia de Substituição , Antibacterianos , Polietilenos , Polifenóis , Vitamina E
12.
J Mater Chem B ; 8(45): 10428-10438, 2020 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-33112351

RESUMO

Periprosthetic joint infection (PJI) is one of the main causes for the failure of joint arthroplasty. In view of the limited clinical effect of oral/injectable antibiotics and the drug resistance problem, there is a pressing need to develop antibacterial implants with therapeutic antimicrobial properties. In this work, we prepared a highly antibacterial ultrahigh molecular weight polyethylene (UHMWPE) implant by incorporating tea polyphenols. The presence of tea polyphenols not only improved the oxidation stability of irradiated UHMWPE, but also gave it the desirable antibacterial property. The potent antibacterial activity was attributed to the tea polyphenols that produced excess intracellular reactive oxygen species and destroyed the bacterial membrane structure. The tea polyphenol-blended UHMWPE had no biological toxicity to human adipose-derived stem cells and effectively reduced bacteria-induced inflammation in vivo. These results indicate that tea polyphenol-blended UHMWPE is promising for joint replacement prostheses with multifunctionality to meet patient satisfaction.


Assuntos
Antibacterianos/farmacologia , Anti-Inflamatórios/farmacologia , Materiais Biocompatíveis/farmacologia , Prótese Articular , Polietilenos/farmacologia , Polifenóis/farmacologia , Animais , Antibacterianos/uso terapêutico , Anti-Inflamatórios/uso terapêutico , Artroplastia de Substituição/efeitos adversos , Bactérias/efeitos dos fármacos , Infecções Bacterianas/etiologia , Infecções Bacterianas/prevenção & controle , Materiais Biocompatíveis/uso terapêutico , Linhagem Celular , Humanos , Prótese Articular/efeitos adversos , Prótese Articular/microbiologia , Masculino , Polietilenos/uso terapêutico , Polifenóis/uso terapêutico , Ratos Sprague-Dawley , Chá/química
13.
J Clin Pharm Ther ; 45(4): 825-827, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32304579

RESUMO

WHAT IS KNOWN AND OBJECTIVE: Despite its frequent use in clinical practice, fentanyl's pro-serotonergic effects are underrecognized, especially in combination with linezolid. Life-threatening reactions can occur. CASE SUMMARY: We report a case of serotonin syndrome developed shortly after the initiation of linezolid in a 63-year-old patient in whom selective serotonin reuptake inhibitor therapy was discontinued for the duration of antibiotic therapy. However, fentanyl transdermal patch treatment was inadvertently continued. Noteworthy, 24 hours following discontinuation of linezolid, the patient experienced complete resolution of symptoms. WHAT IS NEW AND CONCLUSION: Fentanyl can increase the intrasynaptic release of serotonin through their effects on y-amino butyric acid and its phenylpiperidine chemical structure. We illustrate the importance of thorough medication reconciliation and review of all potential drug-to-drug interactions when indicating linezolid therapy to ensure patient safety. We believe that our case provides novel observations and insight that could help recognize similar cases in clinical practice.


Assuntos
Fentanila/efeitos adversos , Linezolida/efeitos adversos , Síndrome da Serotonina/induzido quimicamente , Interações Medicamentosas , Feminino , Humanos , Pessoa de Meia-Idade
14.
J Oral Maxillofac Pathol ; 24(2): 374-382, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33456250

RESUMO

Vitamin C, also known as ascorbic acid, is used as a treatment modality in depigmentation of hyperpigmented spots on the skin and gingiva. This systematic review discusses the studies conducted to assess the effect of Vitamin C on melanin pigmentation. The primary objective was to evaluate the effect of Vitamin C on melanin pigmentation. The secondary objective was to analyze the effect of Vitamin C administration on melanin pigmentation. An electronic database search was conducted from the following databases: PubMed, EBSCOhost, ScienceOpen, EMBASE and Google Scholar. Randomized controlled trials, experimental studies, case-control studies and cohort studies published in peer-reviewed journals in English language were included. Case reports, case series, animal model studies, in vitro studies, studies where Vitamin C was used along with other agents and unpublished research were excluded. Out of 22,580 studies, only 7 studies satisfied the selection criteria. Data extraction sheet was prepared, and the studies were analyzed. Out of the 7 studies analyzed, 1 was a randomized controlled trial and 6 were experimental studies. Vitamin C has been used widely as a depigmenting agent in dermatology. However, there are limited studies conducted on the use of Vitamin C for gingival depigmentation.

15.
ACS Appl Bio Mater ; 3(1): 547-553, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-35019398

RESUMO

Oxidative degradation of ultrahigh molecular weight polyethylene (UHMWPE) bearings is one of the main factors that deteriorates their mechanical properties and abrasive wear resistance, which further results in the failure of total joint replacements. Absorption and diffusion of synovial fluids have been considered as causes of the oxidation of UHMWPE bearings. However, the role of synovial fluids in oxidation of UHMWPE remains elusive. In this work, we aimed to reveal the oxidation mechanism of UHMWPE joints with respect to squalene (a representative component of the synovial fluid). The UHMWPE doped in squalene showed slight oxidation, while severe oxidation was observed when squalene doped UHMWPE was exposed to oxygen atmosphere. Squalene manifested lipid peroxidation with notable oxidation products and oxygen-derived free radicals during thermo-oxidative aging. Lipid peroxidation was deduced to follow two routes including autoxidation and thermal oxidation. The aggressive free radicals of squalene abstracted hydrogen atoms from the UHMWPE chains, initiating the oxidation of UHMWPE artificial joints. These findings not only provide evidence for comprehending the process of squalene-induced UHMWPE oxidation but also are instructive to develop highly oxidative-resistant UHMWPE.

16.
Appl Radiat Isot ; 155: 108901, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31655354

RESUMO

Silicone being a hybrid elastomer is well known for its excellent thermal and mechanical properties, chemical resistance, compatibility with organic and inorganic fillers, nontoxicity, and flexibility. As the reported literature on silicone tungsten composite is rare, thus, a complete possible spectrum of silicone tungsten composites series with tungsten loading of 0-88.1 %wt has been fabricated by RTV method and studied as a flexible gamma shielding material. Flexible silicone/tungsten composite formulations containing different weight percentages of tungsten powder (0, 30.1, 47.8, 59.8, 68.1, and 88.1 wt %) were developed by the room-temperature vulcanization route. Two lead collimators with diameters of 0.6 cm were used to make a narrow beam geometry for gamma rays emitted from a137Cs (gamma-ray energy of 662 keV) point source. Uncollided flux was measured with a NaI(Tl) scintillation detector enclosed in lead shielding to reduce the background radiation level. The measured mass attenuation coefficient for our composites with 88.1 wt % tungsten was 0.1035 cm2/g, which is nearly 3.5% higher than that of commercially available silicone/tungsten composites named T-Flex (nearly 0.095 cm2/g) containing the same tungsten loading. Similarly, superior half value layers (HVL) of our composites with 88.1 % wt loading of tungsten i.e 1.01 cm versus 1.27 cm for the reported T-Flex counterpart with additional advantage of insitu fabrication on complex geometries. It was also found that the effectiveness of gamma-ray shielding increases with increase in density of the composites, which is due to the increase in the weight percent of tungsten powder. Our material will have applications as shielding material for both mobile and stationary radiation sources and it can also be used as fabrication material for gloves, safety shoes, coats, etc. to protect workers in a radiation environment.

17.
Front Psychol ; 10: 2190, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31632320

RESUMO

Purpose: Cochlear implants (CIs) provide reasonable levels of speech recognition quietly, but voice pitch perception is severely impaired in CI users. The central question addressed here relates to how access to acoustic input pre-implantation influences vocal emotion production by individuals with CIs. The objective of this study was to compare acoustic characteristics of vocal emotions produced by prelingually deaf school-aged children with cochlear implants (CCIs) who were implanted at the age of 2 and had no usable hearing before implantation with those produced by children with normal hearing (CNH), adults with normal hearing (ANH), and postlingually deaf adults with cochlear implants (ACI) who developed with good access to acoustic information prior to losing their hearing and receiving a CI. Method: A set of 20 sentences without lexically based emotional information was recorded by 13 CCI, 9 CNH, 9 ANH, and 10 ACI, each with a happy emotion and a sad emotion, without training or guidance. The sentences were analyzed for primary acoustic characteristics of the productions. Results: Significant effects of Emotion were observed in all acoustic features analyzed (mean voice pitch, standard deviation of voice pitch, intensity, duration, and spectral centroid). ACI and ANH did not differ in any of the analyses. Of the four groups, CCI produced the smallest acoustic contrasts between the emotions in voice pitch and emotions in its standard deviation. Effects of developmental age (highly correlated with the duration of device experience) and age at implantation (moderately correlated with duration of device experience) were observed, and interactions with the children's sex were also observed. Conclusion: Although prelingually deaf CCI and postlingually deaf ACI are listening to similar degraded speech and show similar deficits in vocal emotion perception, these groups are distinct in their productions of contrastive vocal emotions. The results underscore the importance of access to acoustic hearing in early childhood for the production of speech prosody and also suggest the need for a greater role of speech therapy in this area.

18.
Clin Orthop Relat Res ; 477(8): 1947-1955, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31107312

RESUMO

BACKGROUND: Synovial fluid components, especially lipids, can trigger oxidation of ultrahigh-molecular-weight polyethylene (UHMWPE) artificial joint components in vivo. The use of antioxidants such as vitamin E effectively diminishes the oxidative cascade by capturing free radicals and reducing the oxidation potential of UHMWPE implants. Using a thermo-oxidative aging method, we recently found that tea polyphenols can enhance the oxidation resistance of irradiated UHMWPE in comparison with commercial vitamin E. However, it is yet unknown whether tea polyphenols can reduce lipid-induced oxidation. QUESTIONS/PURPOSES: We explored whether tea polyphenol-stabilized UHMWPE would exhibit (1) lower squalene absorption; (2) stronger oxidation resistance; and (3) lower content of free radicals than vitamin E-stabilized UHMWPE under a physiologically-motivated in vitro accelerated-aging model. METHODS: Tea polyphenol (lipid-soluble epigallocatechin gallate [lsEGCG]) and vitamin E were blended with UHMWPE powders followed by compression molding and electron beam irradiation at 100 and 150 kGy. Small cubes (n = 3, 60 mg, 4 × 4 × 4 mm) cut from the blocks were doped in squalene at 60°, 80°, 100°, and 120° C for 2 hours. Gravimetric change of the cubes after squalene immersion was measured to assess absorption. Thin films (n = 3, ∼60 µm) were also microtomed from the blocks and were doped at 120° C for 24 hours. Oxidation induction time (n = 3, 5 mg of material from the cubes) and incipient oxidation temperature (n = 3, thin films) were obtained to determine the oxidation stability. Signal intensity of the free radicals, obtained by electron spin resonance spectroscopy, was used to qualitatively rank the antioxidant ability of vitamin E and lsEGCG. RESULTS: Squalene absorption was comparable between lsEGCG/UHMWPE and vitamin E/UHMWPE at a given temperature and radiation dose. The oxidation induction time of 100 kGy-irradiated UHMWPE was increased with lsEGCG compared with vitamin E except at 120° C. For example, the oxidation induction time value of 100 kGy-irradiated lsEGCG/UHMWPE immersed at 60 C was 25.3 minutes (24.2-27.8 minutes), which was 8.3 minutes longer than that of 100 kGy-irradiated vitamin E/UHMWPE which was 17.0 minutes (15.0-17.1 minutes) (p = 0.040). After squalene immersion at 120° C, the incipient oxidation temperature of 100 and 150 kGy irradiated lsEGCG/UHMWPE was 234° C (227-240° C) and 227° C (225-229° C), which was higher than vitamin E-stabilized counterparts with value of 217° C (214-229° C; p = 0.095) and 216° C (207-218° C; p = 0.040), respectively. The electron spin resonance signal of 150 kGy irradiated lsEGCG/UHMWPE was qualitatively weaker than that of 150 kGy irradiated vitamin E/UHMWPE. CONCLUSIONS: lsEGCG-stabilized UHMWPE demonstrated higher oxidation resistance than vitamin E-stabilized UHMWPE after squalene immersion, likely because lsEGCG donates more protons to eliminate macroradicals than vitamin E. CLINICAL RELEVANCE: Our in vitro findings provide support that lsEGCG may be effective in protecting against oxidation that may be associated with synovial fluid-associated oxidation of highly crosslinked UHMWPE joint replacement components.


Assuntos
Antioxidantes/química , Catequina/análogos & derivados , Prótese Articular , Extratos Vegetais/química , Polietilenos/química , Vitamina E/química , Antioxidantes/isolamento & purificação , Camellia sinensis/química , Catequina/química , Catequina/isolamento & purificação , Radicais Livres/química , Oxirredução , Extratos Vegetais/isolamento & purificação , Polietilenos/efeitos da radiação , Falha de Prótese , Esqualeno/química , Fatores de Tempo
19.
Mater Sci Eng C Mater Biol Appl ; 94: 211-219, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30423703

RESUMO

Despite being currently state-of-the-art to prevent the oxidation of irradiated ultrahigh molecular weight polyethylene (UHMWPE) bearings, vitamin E (VE) poses concerns in the loss of cross-linking efficiency and is limited to be used at very low concentrations. It thus emphasizes the urgent demand for more efficient stabilizers. In this study, oxidation stability of highly cross-linked UHMWPE was demonstrated to be enhanced by tea polyphenols, such as lipid-soluble tea polyphenols (lsPPT), epigallocatechin gallate (EGCG), and lipid-soluble epigallocatechin gallate (lsEGCG). These antioxidants were blended with UHMWPE granules and consolidated by compression molding prior to E-beam irradiation. The presence of tea polyphenols substantially prolonged oxidation induction time of the irradiated UHMWPE before and after accelerated aging. Especially, lsEGCG was significantly superior to VE in terms of stabilizing capacity. Explained by the hydrogen donation mechanism, tea polyphenols with multiple phenolic hydroxyls could scavenge more radiation-induced free radicals than VE with only one phenolic hydroxyl, which was verified by the electron spin resonance spectra. Intriguingly, tea polyphenols showed less inhibitive effect on the cross-link density of irradiated UHMWPE than VE. Besides, there is no significant difference in crystallinity, mechanical performance as well as in vitro biocompatibility between the irradiated UHMWPE stabilized by tea polyphenols and VE. These findings highlight tea polyphenols, especially lsEGCG, are promising alternatives to extend the life span of UHMWPE implants.


Assuntos
Reagentes de Ligações Cruzadas/química , Prótese Articular , Polietilenos/química , Polifenóis/farmacologia , Chá/química , Animais , Linhagem Celular , Espectroscopia de Ressonância de Spin Eletrônica , Camundongos , Oxirredução , Polifenóis/química , Resistência à Tração
20.
Br J Dermatol ; 179(6): 1351-1357, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-29750336

RESUMO

BACKGROUND: Porphyria cutanea tarda (PCT) is the most common human porphyria. It is caused by hepatic deficiency of uroporphyrinogen decarboxylase activity, which is acquired in the presence of multiple susceptibility factors. PCT presents clinically with cutaneous blistering photosensitivity and is readily treatable with either repeated phlebotomy or 4-aminoquinoline antimalarials. OBJECTIVES: To perform a systematic review and meta-analysis to compare the effectiveness of these quite different treatment approaches, especially on relapse rates (RRs) after achieving remission. METHODS: Published studies that included follow-up for at least 1 year after treatment of PCT were included. The primary study outcome was PCT relapse. Pooled data are reported as the RRs per person-year of follow-up with 95% confidence intervals (CIs). RESULTS: Of 375 articles identified as pertaining to PCT treatment, 12 were eligible for analysis. Of these, five used high-dose 4-aminoquinoline regimens (two combined with phlebotomy and three without phlebotomy), five used low-dose 4-aminoquinoline regimens and three used phlebotomy. RRs during the year after treatment were similar for the high- and low-dose 4-aminoquinoline groups (35-36%) and lower in the phlebotomy group (20%). The pooled RRs with their 95% CIs were 8·6 (3·9-13·3) per 100 person-years in the high-dose 4-aminoquinoline group, 17·1 (8·9-25·3) per 100 person-years in the low-dose 4-aminoquinoline group and 5·1 (0·5-10·6) per 100 person-years in the phlebotomy group. Subgroup and sensitivity analyses showed similar results. CONCLUSIONS: Clinical or biochemical RRs ranged from 5 to 17 per 100 person-years after remission of PCT. Relapses were somewhat more frequent after remission with 4-aminoquinoline regimens than after remission following phlebotomy. Prospective studies are needed to define better how often relapses occur with these treatments after documenting both clinical and biochemical remission of PCT.


Assuntos
Aminoquinolinas/administração & dosagem , Antimaláricos/administração & dosagem , Flebotomia , Porfiria Cutânea Tardia/terapia , Relação Dose-Resposta a Droga , Humanos , Recidiva , Resultado do Tratamento
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