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1.
Polymers (Basel) ; 15(23)2023 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-38231978

RESUMO

The fisheries industry encounters distinct packaging challenges, including the need to protect perishable seafood from rapid spoilage caused by UV radiation while allowing for reuse. This study tackles these issues by introducing advanced high-density polyethylene (HDPE) composites enhanced with a UV stabilizer and inorganic fillers, such as diatomaceous earth/zinc oxide (DZ). Our investigation explores the transformative effects of weathering on these pioneering composites, evaluating shifts in mechanical, physical, thermal properties, and sub-zero temperature stability. Incorporating a UV stabilizer alongside DZ within the HDPE matrix significantly enhances mechanical performance and weathering resilience. These enhancements extend the longevity of seafood packaging while preserving product quality. Moreover, our findings reveal a substantial breakthrough in antimicrobial properties. The inclusion of DZ, with or without a UV stabilizer, results in an impressive up to 99% enhancement in antibacterial activity against both Gram-positive and Gram-negative bacteria. This discovery not only bolsters the protective attributes of HDPE packaging but also presents a compelling case for the development of active packaging materials derived from DE/ZnO composites. This study bridges the gap between packaging and seafood quality, introducing advanced polymeric packaging technology for seafood products. It highlights the mutually beneficial link between packaging improvements and ensuring seafood quality, meeting industry needs while promoting sustainability.

2.
Polymers (Basel) ; 14(23)2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36501622

RESUMO

One of the key factors of supporting the rapidly expanding seafood product industry in terms of quality control is the utilization of active packaging materials. Microorganisms are primarily responsible for the perishability and rapid disintegration of seafood. The incorporation of an inorganic compound, such as silica-based diatomaceous earth (DE), and a metal oxide, such as zinc oxide (ZnO), is proposed to develop active packaging materials with excellent antibacterial activity, minimized fishy odor, and brittleness at subzero temperatures. The mechanical, morphological, and physicochemical properties of these materials were investigated. The results show that the addition of DE/ZnO improved the antibacterial activity of high-density polyethylene (HDPE) samples by up to approximately 95% against both gram-positive and -negative bacteria. Additionally, it enhanced the Izod strength and stability at subzero temperatures of the samples. The odor evaporation test revealed that trimethylamine can be minimized in proportion to increasing DE/ZnO composite concentration. As a result, the development of active packaging materials from DE/ZnO composites is an emerging polymeric packaging technology for seafood products, wherein packaging and seafood quality are linked.

3.
Blood Adv ; 6(16): 4740-4762, 2022 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-35816645

RESUMO

Optimal treatment strategies for (relapsed and refractory [R/R]) peripheral T-cell lymphoma (PTCL) have not been well defined, and with the approval of several novel single agents (SA), the comparative efficacy of combination chemotherapy (CC) to single-agent strategies remains unclear. We conducted a meta-analysis to evaluate overall response rates (ORR) and toxicities of SA to CC. MEDLINE, Embase, Web of Science Core Collection, and Cochrane were systematically searched for phase I, phase II, and phase III trials investigating a defined SA or an anthracycline-, ifosfamide-, gemcitabine-, and platinum-based regimens. One hundred and fifty-one articles were included, encompassing single and combinations of 60 phase I trials involving 1075 patients, 95 phase II trials involving 3246, and 23 phase III trials involving 1888 patients. There was a high degree of heterogeneity in the trials. Using a random-effects model, the estimated ORR for SA in phase I trials were 40% (95% confidence interval [CI], 34.7%, 46.9%) relative to 41% for CC (95% CI, 27.4%, 56.1%; P = .97) and in phase II trials 34.4% (95% CI, 30.4%, 38.7%) for SA vs 55.3% (95% CI, 31%, 77.2%; P = .1) for CC. There were significant subgroup differences in ORR between histological subtypes of PTCL and drug classes. Our results highlight SA as an attractive outpatient option for R/R PTCL, and their incorporation in the development of upfront treatment paradigms merits urgent consideration. Our results underscore enrollment in clinical trials of SA as a critical strategy for R/R PTCL.


Assuntos
Linfoma de Células T Periférico , Recidiva Local de Neoplasia , Antibióticos Antineoplásicos/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Humanos , Ifosfamida , Linfoma de Células T Periférico/tratamento farmacológico , Linfoma de Células T Periférico/patologia , Recidiva Local de Neoplasia/tratamento farmacológico
4.
Mil Med ; 2022 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-35769049

RESUMO

INTRODUCTION: Intravenous immunoglobulin (IVIG) preparations, used for the treatment of antibody deficiencies, provide a glimpse of the general population's antibody profile as each preparation is generated from a pool of thousands of donors. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus responsible for the coronavirus disease 2019 (Covid-19) pandemic, and a vaccine for the prevention of Covid-19 was authorized for emergency use in December 2020. We completed a longitudinal analysis of SARS-CoV-2 antibody levels in commercial IVIG preparations. MATERIALS AND METHODS: We collected IVIG samples from our infusion clinic. IVIG product lot number, product name, and manufacturer information were recorded, with the date of preparation verified from the manufacturer. SARS-CoV-2 antibody titers as well as total immunoglobulin levels were measured using commercially available assays. The study received Institutional Review Board approval. RESULTS: We found no SARS-CoV-2 antibodies in preparations generated on or before January 2020. Overall, SARS-CoV-2 antibody levels in IVIG preparations tended to increase with progressing preparation date. We observed a dramatic and continual rise of SARS-CoV-2 antibody levels in IVIG preparations made in the beginning after January 2021, coinciding with the peak in incidence of confirmed cases and availability of Covid-19 vaccines in the United States. CONCLUSION: SARS-CoV-2 antibody levels in IVIG mirror case prevalence, and vaccination resulted in a far more rapid rate of rise in antibody levels. IVIG preparations or serum repositories can provide an accessible way to model a population's evolving novel pathogen exposure, immunity, and vaccine response.

5.
J Allergy Clin Immunol Pract ; 10(9): 2424-2435.e5, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35032694

RESUMO

BACKGROUND: Hereditary-alpha tryptasemia (HαT) is the most common etiology for elevated basal serum tryptase (BST). However, the utility of tryptase genotyping of individuals with elevated BST in general clinical practice remains undefined. Moreover, studies showing associations between elevated BST and chronic kidney disease (CKD), myelodysplastic syndrome (MDS), rheumatoid arthritis, or eosinophilic esophagitis did not include tryptase genotyping. OBJECTIVE: To determine the utility of tryptase genotyping among individuals with moderate elevations in BST at a regional health system. METHODS: Clinical and laboratory data from 109 subjects with basal tryptase values of 7.5 ng/mL or greater who were tested for HαT or had a disorder previously linked to elevated BST were collected retrospectively by chart review. RESULTS: Fifty-eight subjects had elevated BST defined as 11.5 ng/mL or greater. HαT was found in 63.8% (n = 37), 12.1% (n = 7) had CKD, and 20.7% (n = 12) had clonal myeloid disorders. A total of 6.9% (n = 4) with elevated BST had negative testing for HαT, CKD, and myeloid neoplasms. Two subjects with CKD, 1 subject with MDS, and 1 with myeloid hypereosinophilic syndrome had negative testing for HαT. Among subjects with elevated BST and more than 1 tryptase measurement, 41.5% (n = 22) had BST variability that exceeded the 20% plus 2 formula. Increased BST variability was found in subjects with HαT, all forms of mastocytosis, CKD, MDS, and those with no associated diagnosis. CONCLUSIONS: HαT, CKD, and clonal myeloid disorders or a combination of the 3 constitute approximately 90% of individuals with elevated BST in clinical practice. Myeloid neoplasms were over-represented in this cohort relative to population prevalence data suggesting tryptase measurement selection bias by clinicians or higher prevalence. Elevated BST is associated with increased tryptase variability, regardless of etiology.


Assuntos
Insuficiência Renal Crônica , Triptases , Humanos , Mastócitos , Mastocitose/diagnóstico , Síndromes Mielodisplásicas/diagnóstico , Insuficiência Renal Crônica/diagnóstico , Estudos Retrospectivos , Triptases/sangue
6.
J Allergy Clin Immunol Glob ; 1(3): 154-161, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37781270

RESUMO

Background: Imported fire ant (IFA) venom immunotherapy (VIT) is the only disease-modifying treatment reported to be effective at decreasing the risk of systemic reactions (SRs) to IFA stings. Objective: Our aims were to determine the baseline rates of IFA sensitization in subjects, describe IFA VIT prescribing patterns across the military health system (MHS), and retrospectively evaluate the safety and efficacy of IFA VIT. Methods: We prospectively compared IFA sensitization in participants with and without an SR to flying Hymenoptera venom. Separately, IFA VIT prescription records were extracted from a centralized repository, and rates were described across the MHS. Additionally, we retrospectively reviewed the clinical course of patients being treated with IFA VIT at 11 military treatment facilities. Results: The in vitro IFA sensitization rates in our prospective cohort ranged from 19.1% to 24.1%. Sensitization rates did not differ statistically between the subjects with or without an SR to flying Hymenoptera venom. We found that 60.9% of all MHS IFA VIT prescriptions (491 of 806) were from the 11 facilities in this study. We retrospectively identified 137 subjects actively undergoing IFA VIT. Among the subjects actively undergoing IFA VIT, 28 reported an SR to IFA venom and repeat stings by IFAs after reaching VIT maintenance, and 85.7% (24 of 28) of the subjects noted symptoms no worse than a large swelling reaction after a repeat IFA sting. Notably, only 2.9% of the subjects (4 of 137) had an SR due to VIT. Conclusion: This study's results align with those of prior IFA sensitization reports. A substantial proportion of patients undergoing IFA VIT experienced protection against anaphylaxis with reexposure, with relatively few adverse events.

7.
HPB (Oxford) ; 24(4): 568-574, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34702628

RESUMO

BACKGROUND: Maintaining low central venous pressure (CVP) is an effective strategy to reduce blood loss during hepatic resection. As an alternative to measuring CVP, which requires the placement of a central venous catheter, bioelectrical impedance analysis (BIA) is a noninvasive method recently used for monitoring volume status in critically ill patients. METHODS: We investigated 192 patients who underwent hepatic resection from January 2017 to December 2020. The ratio of extracellular water:total body water (ECW/TBW), as an index of volume status, was measured using InBody S10 (Biospace, Seoul, Korea). The correlation between the ECW/TBW and CVP was determined, and their influences on operative outcomes were analyzed. RESULTS: ECW/TBW and CVP showed a significant correlation; an ECW/TBW <0.378 correlated with a CVP <5 mmHg (R2 = 0.839, P<0.001). Estimated blood loss (EBL) was significantly increased in patients with an ECW/TBW ≥0.378 compared to those with a ratio <0.378 (508 ± 321 vs. 324 ± 193, mL, P<0.001). Identified predictors for an EBL ≥500 mL were operative time (odds ratio [OR], 1.008; 95% confidence interval [CI], 1.001-1.015; P = 0.021) and an ECW/TBW <0.378 (OR, 0.263; 95% CI, 0.121-0.572; P = 0.001). CONCLUSIONS: BIA can be utilized for preoperative volume assessment to minimize blood loss during hepatic resection.


Assuntos
Composição Corporal , Água Corporal , Impedância Elétrica , Humanos , República da Coreia , Seul
8.
J Allergy Clin Immunol Pract ; 10(3): 837-843.e3, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34534718

RESUMO

BACKGROUND: Diagnosis of patients with hymenoptera venom hypersensitivity consists of elucidating clinical symptoms suggestive of systemic reaction (SR) and then confirmation of sensitization via intradermal skin testing (IDST) first and serum IgE assays such as ImmunoCAP (ICAP) as a complementary modality of diagnosis. OBJECTIVE: Determine the concordance between ICAP and IDST in patients with a clinical history suggestive of hymenoptera venom SR. Determine whether venom immunotherapy would change on the basis of IDST versus ICAP results. METHODS: A prospective diagnostic study was designed to test the concordance between IDST and ICAP venom testing in the diagnosis of hymenoptera venom hypersensitivity. This study entailed testing both IDST and ICAP for 5 hymenoptera venoms (honey bee, wasp, yellow jacket, yellow hornet, and white-faced hornet) in both a case group with SR to hymenoptera venom (N = 70) and a control group without SR (N = 51). RESULTS: Significant discordance was observed between positive IDST and ICAP results for any of the 5 hymenoptera venoms (McNemar test, P = .001). In the case group, there was significant discordance for wasp (P < .0001), yellow jacket (P = .002), and white-faced hornet (P = .02). More than 47% of the case patients would have different venom immunotherapy prescriptions if ICAP and IDST had been performed during initial diagnosis versus IDST alone. CONCLUSIONS: Our study shows significant discordance between IDST and ICAP; however, they are complementary. On the basis of our data, we propose ICAP testing first followed by IDST for ICAP-negative venoms as an alternative and efficient diagnostic strategy.


Assuntos
Venenos de Artrópodes , Venenos de Abelha , Himenópteros , Hipersensibilidade , Mordeduras e Picadas de Insetos , Vespas , Animais , Venenos de Artrópodes/uso terapêutico , Dessensibilização Imunológica , Humanos , Hipersensibilidade/tratamento farmacológico , Hipersensibilidade/terapia , Imunoglobulina E , Fatores Imunológicos , Mordeduras e Picadas de Insetos/tratamento farmacológico , Mordeduras e Picadas de Insetos/terapia , Estudos Prospectivos , Venenos de Vespas/uso terapêutico
9.
Mil Med ; 187(9): e1556-e1558, 2022 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-33851711

RESUMO

Cholinergic urticaria is a common disorder that has been associated with anaphylaxis. We report the events, workup, and eventual second dose vaccination of a patient at the Walter Reed National Military Medical Center, who had immediate anaphylaxis after administration of the first Pfizer-BioNTech Covid-19 (BNT162b2) vaccine dose. During the initial evaluation after anaphylaxis, the patient described a history of symptoms suspicious for cholinergic urticaria but had never had this condition confirmed with standardized testing. After the episode of anaphylaxis, we performed several studies including immediate hypersensitivity skin testing, which did not demonstrate vaccine or component sensitization. We then performed an exercise provocation challenge and confirmed the diagnosis of cholinergic urticaria. These results, combined with the patient history, suggested that the episode of anaphylaxis was most likely driven by a severe flare of cholinergic urticaria. After obtaining the patient's consent, she received and tolerated her second dose without any objective findings of anaphylaxis. We conclude that patients with mast cell disorders or anaphylaxis after their first Covid-19 immunization will benefit from referral to an allergist since receipt of their second Covid-19 immunization may be possible.


Assuntos
Anafilaxia , Vacinas contra COVID-19 , Urticária , Feminino , Humanos , Anafilaxia/etiologia , Anafilaxia/diagnóstico , Vacina BNT162/efeitos adversos , Colinérgicos , COVID-19/prevenção & controle , Vacinas contra COVID-19/efeitos adversos , Urticária/complicações
10.
Curr Med Imaging ; 16(9): 1182-1184, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33135609

RESUMO

Hemangiomas are benign tumours that commonly develop in the skin, mucosal surfaces, and soft tissues. However, intranodal hemangiomas are extremely rare and are among the benign primary vascular abnormalities of the lymph nodes that include lymphangioma, hemangioendothelioma, angiomyomatous hamartoma and hemangiomas. The hemangioma in the pelvic lymph node has never been reported in the English literature. Herein, we described an extremely rare case of hemangioma in the pelvic lymph node, simulating a benign metastasizing leiomyoma.


Assuntos
Hamartoma , Hemangioendotelioma , Hemangioma , Linfangioma , Humanos , Linfonodos
11.
Glia ; 68(10): 2040-2056, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32187401

RESUMO

Fused in sarcoma (FUS) is a predominantly nuclear multifunctional RNA/DNA-binding protein that regulates multiple aspects of gene expression. FUS mutations are associated with familial amyotrophic lateral sclerosis (fALS) and frontotemporal lobe degeneration (FTLD) in humans. At the molecular level, the mutated FUS protein is reduced in the nucleus but accumulates in cytoplasmic granules. Oligodendrocytes (OL) carrying clinically relevant FUS mutations contribute to non-cell autonomous motor neuron disease progression, consistent with an extrinsic mechanism of disease mediated by OL. Knocking out FUS globally or in neurons lead to behavioral abnormalities that are similar to those present in FTLD. In this study, we sought to investigate whether an extrinsic mechanism mediated by loss of FUS function in OL contributes to the behavioral phenotype. We have generated a novel conditional knockout (cKO) in which Fus is selectively depleted in OL (FusOL cKO). The FusOL cKO mice show increased novelty-induced motor activity and enhanced exploratory behavior, which are reminiscent of some manifestations of FTLD. The phenotypes are associated with greater myelin thickness, higher number of myelinated small diameter axons without an increase in the number of mature OL. The expression of the rate-limiting enzyme of cholesterol biosynthesis (HMGCR) is increased in white matter tracts of the FusOL cKO and results in higher cholesterol content. In addition, phosphorylation of Akt, an important regulator of myelination is increased in the FusOL cKO. Collectively, this work has uncovered a novel role of oligodendrocytic Fus in regulating myelin deposition through activation of Akt and cholesterol biosynthesis.


Assuntos
Colesterol/metabolismo , Hipercinese/metabolismo , Bainha de Mielina/metabolismo , Oligodendroglia/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteína FUS de Ligação a RNA/deficiência , Animais , Colesterol/genética , Hipercinese/genética , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Bainha de Mielina/genética , Proteínas Proto-Oncogênicas c-akt/genética , Proteína FUS de Ligação a RNA/genética
12.
Plant J ; 102(5): 992-1007, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31925835

RESUMO

Sessile plants have evolved distinct mechanisms to respond and adapt to adverse environmental conditions through diverse mechanisms including RNA processing. While the role of RNA processing in the stress response is well understood for Arabidopsis thaliana, limited information is available for rice (Oryza sativa). Here, we show that OsFKBP20-1b, belonging to the immunophilin family, interacts with the splicing factor OsSR45 in both nuclear speckles and cytoplasmic foci, and plays an essential role in post-transcriptional regulation of abiotic stress response. The expression of OsFKBP20-1b was highly upregulated under various abiotic stresses. Moreover genetic analysis revealed that OsFKBP20-1b positively affected transcription and pre-mRNA splicing of stress-responsive genes under abiotic stress conditions. In osfkbp20-1b loss-of-function mutants, the expression of stress-responsive genes was downregulated, while that of their splicing variants was increased. Conversely, in plants overexpressing OsFKBP20-1b, the expression of the same stress-responsive genes was strikingly upregulated under abiotic stress. In vivo experiments demonstrated that OsFKBP20-1b directly maintains protein stability of OsSR45 splicing factor. Furthermore, we found that the plant-specific OsFKBP20-1b gene has uniquely evolved as a paralogue only in some Poaceae species. Together, our findings suggest that OsFKBP20-1b-mediated RNA processing contributes to stress adaptation in rice.


Assuntos
Oryza/metabolismo , Proteínas de Plantas/metabolismo , Fatores de Processamento de RNA/metabolismo , Processamento Alternativo/genética , Processamento Alternativo/fisiologia , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Oryza/genética , Proteínas de Plantas/genética , Ligação Proteica , Processamento Pós-Transcricional do RNA/genética , Processamento Pós-Transcricional do RNA/fisiologia , Fatores de Processamento de RNA/genética , Estresse Fisiológico/genética , Estresse Fisiológico/fisiologia
13.
Front Neurosci ; 12: 131, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29556175

RESUMO

The neural mechanisms underlying alcohol dependence are not well-understood. GABAergic neurons in the ventral tegmental area (VTA) are a relevant target for ethanol. They are inhibited by ethanol at physiologically-relevant levels in vivo and display marked hyperexcitability during withdrawal. In the present study, we examined the effects of the GABA(A) receptor agonist muscimol on VTA neurons ex vivo following withdrawal from acute and chronic ethanol exposure. We used standard cell-attached mode electrophysiology in the slice preparation to evaluate the effects of muscimol on VTA GABA neuron firing rate following exposure to acute and chronic ethanol in male CD-1 GAD-67 GFP mice. In the acute condition, the effect of muscimol on VTA neurons was evaluated 24 h and 7 days after a single in vivo dose of saline or ethanol. In the chronic condition, the effect of muscimol on VTA neurons was evaluated 24 h and 7 days after either 2 weeks of twice-daily IP ethanol or saline or following exposure to chronic intermittent ethanol (CIE) vapor or air for 3 weeks. VTA GABA neuron firing rate was more sensitive to muscimol than DA neuron firing rate. VTA GABA neurons, but not DA neurons, were resistant to the inhibitory effects of muscimol recorded 24 h after a single ethanol injection or chronic ethanol exposure. Administration of the NMDA receptor antagonist MK-801 before ethanol injection restored the sensitivity of VTA GABA neurons to muscimol inhibition. Seven days after ethanol exposure, VTA GABA neuron firing rate was again susceptible to muscimol's inhibitory effects in the acute condition, but the resistance persisted in the chronic condition. These findings suggest that VTA GABA neurons exclusively undergo a shift in GABA(A) receptor function following acute and chronic exposure. There appears to be transient GABA(A) receptor-mediated plasticity after a single exposure to ethanol that is mediated by NMDA glutamate receptors. In addition, the resistance to muscimol inhibition in VTA GABA neurons persists in the dependent condition, which may contribute to the the hyperexcitability of VTA GABA neurons and inhibition of VTA DA neurons during withdrawal as well as the motivation to seek alcohol.

14.
Front Plant Sci ; 6: 797, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26483814

RESUMO

OsCYP21-4 is a rice cyclophilin protein that binds to cyclosporine A, an immunosuppressant drug. CYP21-4s in Arabidopsis and rice were previously shown to function as mitochondrial cyclophilins, as determined by TargetP analysis. In the current study, we found that OsCYP21-4-GFP localized to the Golgi, rather than mitochondria, in Nicotiana benthamiana leaves, which was confirmed based on its co-localization with cis Golgi α-ManI-mCherry protein. OsCYP21-4 transcript levels increased in response to treatments with various abiotic stresses and the phytohormone abscisic acid, revealing its stress-responsiveness. CYP21-4 homologs do not possess key peptidyl prolyl cis/trans isomerase (PPIase) activity/cyclosporine A (CsA) binding residues, and recombinant OsCYP21-4 protein did not convert the synthetic substrate Suc-AAPF-pNA via cis- trans- isomerization in vitro. In addition, transgenic plants overexpressing OsCYP21-4 exhibited increased tolerance to salinity and hydrogen peroxide treatment, along with increased peroxidase activity. These results demonstrate that OsCYP21-4 is a novel Golgi-localized cyclophilin that plays a role in oxidative stress tolerance, possibly by regulating peroxidase activity.

16.
Fertil Steril ; 82(4): 963-5, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15482782

RESUMO

Irradiation of in-vitro-matured bovine oocytes with x-rays of different durations was performed to develop an alternative to conventional mechanical enucleation methods in somatic cell nuclear transfer. No significant difference in embryo development to the blastocyst stage was detected between nonmechanical and mechanical methods, and cytologic analyses of karyotype and microtubule formation showed the potential availability of x-ray irradiation.


Assuntos
Bovinos/embriologia , Fusão Celular/veterinária , Técnicas de Transferência Nuclear , Oócitos/citologia , Animais , Desenvolvimento Embrionário/fisiologia , Feminino , Raios X
17.
J Food Prot ; 66(8): 1495-8, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12929845

RESUMO

The antimicrobial activity of native chitosan was compared to that of lipase-degraded chitosan. The effects of O-carboxymethylated (O-CM) substitution on native (molecular weight, 120; degree of deacetylation, 84.71%) and lipase-degraded chitosans were also investigated. The antimicrobial activity of native chitosan was more extensive than that of lipase-degraded chitosan; however, lipase-degraded chitosan was still highly effective and more water-soluble. O-CM chitosan derived from degraded chitosan was more effective than O-CM chitosan derived from native chitosan. O-CM substitution enhanced lipase-degraded chitosan's antimicrobial activity without reducing its solubility.


Assuntos
Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Quitina/análogos & derivados , Quitina/farmacologia , Acetilação , Anti-Infecciosos/química , Bactérias/crescimento & desenvolvimento , Quitina/química , Quitosana , Relação Dose-Resposta a Droga , Lipase/metabolismo , Peso Molecular , Solubilidade
18.
J Agric Food Chem ; 50(7): 1876-82, 2002 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-11902927

RESUMO

Response surface methodology (RSM) was used for controlling molecular weight (MW) and degree of deacetylation (DOD) of chitosan in chemical processing. In a reduced model, MW of chitosan is y = 1736166.406 - 250.745X(1)X(2) - 265.452X(2)X(3), with R( 2) = 0.86, and DOD of chitosan is y = 30.6069 + 0.3396X(1) + 0.4948X(2) + 0.0094X(3)(2), with R( 2) = 0.89. MW of chitosan depends on the crossproduct of temperature and NaOH concentration and the crossproduct of NaOH concentration and time, and DOD depends linearly on temperature and NaOH concentration, and quadratically on time. Chitosan was widely depolymerized in a range from 1,100 kDa to 100 kDa and deacetylated from 67.3 to 95.7% by NaOH alkaline treatment. MW and DOD of chitosan were drastically decreased and increased, respectively, with increase of temperature, reaction time, and NaOH concentration. Furthermore, the rate of MW decrease and DOD increase of chitosan gradually decreased with prolonged reaction time.


Assuntos
Quitina/química , Acetilação , Química/instrumentação , Quitina/análogos & derivados , Quitosana , Peso Molecular , Hidróxido de Sódio , Temperatura
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