Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
World J Gastrointest Oncol ; 15(6): 1036-1050, 2023 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-37389112

RESUMO

BACKGROUND: Perihilar cholangiocarcinoma (pCCA) has a poor prognosis and urgently needs a better predictive method. The predictive value of the age-adjusted Charlson comorbidity index (ACCI) for the long-term prognosis of patients with multiple malignancies was recently reported. However, pCCA is one of the most surgically difficult gastrointestinal tumors with the poorest prognosis, and the value of the ACCI for the prognosis of pCCA patients after curative resection is unclear. AIM: To evaluate the prognostic value of the ACCI and to design an online clinical model for pCCA patients. METHODS: Consecutive pCCA patients after curative resection between 2010 and 2019 were enrolled from a multicenter database. The patients were randomly assigned 3:1 to training and validation cohorts. In the training and validation cohorts, all patients were divided into low-, moderate-, and high-ACCI groups. Kaplan-Meier curves were used to determine the impact of the ACCI on overall survival (OS) for pCCA patients, and multivariate Cox regression analysis was used to determine the independent risk factors affecting OS. An online clinical model based on the ACCI was developed and validated. The concordance index (C-index), calibration curve, and receiver operating characteristic (ROC) curve were used to evaluate the predictive performance and fit of this model. RESULTS: A total of 325 patients were included. There were 244 patients in the training cohort and 81 patients in the validation cohort. In the training cohort, 116, 91 and 37 patients were classified into the low-, moderate- and high-ACCI groups. The Kaplan-Meier curves showed that patients in the moderate- and high-ACCI groups had worse survival rates than those in the low-ACCI group. Multivariable analysis revealed that moderate and high ACCI scores were independently associated with OS in pCCA patients after curative resection. In addition, an online clinical model was developed that had ideal C-indexes of 0.725 and 0.675 for predicting OS in the training and validation cohorts. The calibration curve and ROC curve indicated that the model had a good fit and prediction performance. CONCLUSION: A high ACCI score may predict poor long-term survival in pCCA patients after curative resection. High-risk patients screened by the ACCI-based model should be given more clinical attention in terms of the management of comorbidities and postoperative follow-up.

2.
Front Immunol ; 13: 974872, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36466835

RESUMO

Background: Growing evidence indicates that lipid metabolism disorders and gut microbiota dysbiosis were related to the progression of non-alcoholic fatty liver disease (NAFLD). Apoptosis-stimulating p53 protein 2 (ASPP2) has been reported to protect against hepatocyte injury by regulating the lipid metabolism, but the mechanisms remain largely unknown. In this study, we investigate the effect of ASPP2 deficiency on NAFLD, lipid metabolism and gut microbiota using ASPP2 globally heterozygous knockout (ASPP2+/-) mice. Methods: ASPP2+/- Balb/c mice were fed with methionine and choline deficient diet for 3, 10 and 40 day to induce an early and later-stage of NAFLD, respectively. Fresh fecal samples were collected and followed by 16S rRNA sequencing. HPLC-MRM relative quantification analysis was used to identify changes in hepatic lipid profiles. The expression level of innate immunity-, lipid metabolism- and intestinal permeability-related genes were determined. A spearman's rank correlation analysis was performed to identify possible correlation between hepatic medium and long-chain fatty acid and gut microbiota in ASPP2-deficiency mice. Results: Compared with the WT control, ASPP2-deficiency mice developed moderate steatosis at day 10 and severe steatosis at day 40. The levels of hepatic long chain omega-3 fatty acid, eicosapentaenoic (EPA, 20:5 n-3) and docosahexaenoic (DHA, 22:6 n-3), were decreased at day 10 and increased at day 40 in ASPP+/- mice. Fecal microbiota analysis showed significantly increased alpha and beta diversity, as well as the composition of gut microbiota at the phylum, class, order, family, genus, species levels in ASPP2+/- mice. Moreover, ASPP-deficiency mice exhibited impaired intestinal barrier function, reduced expression of genes associated with chemical barrier (REG3B, REG3G, Lysozyme and IAP), and increased expression of innate immune components (TLR4 and TLR2). Furthermore, correlation analysis between gut microbiota and fatty acids revealed that EPA was significantly negatively correlated with Bifidobacterium family. Conclusion: Our findings suggested that ASPP2-deficiency promotes the progression of NAFLD, alterations in fatty acid metabolism and gut microbiota dysbiosis. The long chain fatty acid EPA was significantly negatively correlated with Bifidobacterial abundance, which is a specific feature of NAFLD in ASPP2-deficiency mice. Totally, the results provide evidence for a mechanism of ASPP2 on dysregulation of fatty acid metabolism and gut microbiota dysbiosis.


Assuntos
Microbioma Gastrointestinal , Hepatopatia Gordurosa não Alcoólica , Camundongos , Animais , Hepatopatia Gordurosa não Alcoólica/etiologia , Metabolismo dos Lipídeos , Disbiose , Proteína Supressora de Tumor p53 , RNA Ribossômico 16S/genética , Bifidobacterium , Ácidos Graxos
3.
Biosci Rep ; 40(1)2020 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-31850493

RESUMO

BACKGROUND: Osteosarcoma is the most common primary bone malignancy in children and adolescents. In order to find factors related to its recurrence, and thus improve recovery prospects, a powerful clinical signature is needed. Long noncoding RNAs (lncRNAs) are essential in osteosarcoma processes and development, and here we report significant lncRNAs to aid in earlier diagnosis of osteosarcoma. METHODS: A univariate Cox proportional hazards regression analysis and a multivariate Cox regression analysis were used to analyze osteosarcoma patients' lncRNA expression data from the Therapeutically Applicable Research To Generate Effective Treatments (TARGET), a public database. RESULTS: A lncRNA signature consisting of three lncRNAs (RP1-261G23.7, RP11-69E11.4 and SATB2-AS1) was selected. The signature was used to sort patients into high-risk and low-risk groups with meaningful recurrence rates (median recurrence time 16.80 vs. >128.22 months, log-rank test, P<0.001) in the training group, and predictive ability was validated in a test dataset (median 16.32 vs. >143.80 months, log-rank test, P=0.006). A multivariate Cox regression analysis showed that the significant lncRNA was an independent prognostic factor for osteosarcoma patients. Functional analysis suggests that these lncRNAs were related to the PI3K-Akt signaling pathway, the Wnt signaling pathway, and the G-protein coupled receptor signaling pathway, all of which have various, important roles in osteosarcoma development. The significant 3-lncRNA set could be a novel prediction biomarker that could aid in treatment and also predict the likelihood of recurrence of osteosarcoma in patients.


Assuntos
Neoplasias Ósseas/genética , Marcadores Genéticos/genética , Recidiva Local de Neoplasia/genética , Osteossarcoma/genética , RNA Longo não Codificante/genética , RNA Mensageiro/genética , Transcriptoma , Adolescente , Adulto , Neoplasias Ósseas/patologia , Neoplasias Ósseas/terapia , Criança , Pré-Escolar , Bases de Dados Genéticas , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Humanos , Masculino , Recidiva Local de Neoplasia/patologia , Osteossarcoma/patologia , Osteossarcoma/terapia , Valor Preditivo dos Testes , Medição de Risco , Fatores de Risco , Resultado do Tratamento , Adulto Jovem
4.
World J Gastroenterol ; 21(15): 4517-25, 2015 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-25914460

RESUMO

AIM: To investigate the molecular mechanism for regulation of cholesterol metabolism by hepatitis C virus (HCV) core protein in HepG2 cells. METHODS: HCV genotype 1b core protein was cloned and expressed in HepG2 cells. The cholesterol content was determined after transfection. The expression of sterol regulatory element binding protein 2 (SREBP2) and the rate-limiting enzyme in cholesterol synthesis (HMGCR) was measured by quantitative real-time PCR and immunoblotting after transfection. The effects of core protein on the SREBP2 promoter and 3'-untranslated region were analyzed by luciferase assay. We used different target predictive algorithms, microRNA (miRNA) mimics/inhibitors, and site-directed mutation to identify a putative target of a particular miRNA. RESULTS: HCV core protein expression in HepG2 cells increased the total intracellular cholesterol level (4.05 ± 0.17 vs 6.47 ± 0.68, P = 0.001), and this increase corresponded to an increase in SREBP2 and HMGCR mRNA levels (P = 0.009 and 0.037, respectively) and protein expression. The molecular mechanism study revealed that the HCV core protein increased the expression of SREBP2 by enhancing its promoter activity (P = 0.004). In addition, miR-185-5p expression was tightly regulated by the HCV core protein (P = 0.041). Moreover, overexpression of miR-185-5p repressed the SREBP2 mRNA level (P = 0.022) and protein expression. In contrast, inhibition of miR-185-5p caused upregulation of SREBP2 protein expression. miR-185-5p was involved in the regulation of SREBP2 expression by HCV core protein. CONCLUSION: HCV core protein disturbs the cholesterol homeostasis in HepG2 cells via the SREBP2 pathway; miR-185-5p is involved in the regulation of SREBP2 by the core protein.


Assuntos
Colesterol/metabolismo , MicroRNAs/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Proteínas do Core Viral/metabolismo , Regiões 3' não Traduzidas , Sítios de Ligação , Regulação da Expressão Gênica , Células Hep G2 , Homeostase , Humanos , Hidroximetilglutaril-CoA Redutases/metabolismo , MicroRNAs/genética , Regiões Promotoras Genéticas , Proteína de Ligação a Elemento Regulador de Esterol 2/genética , Transfecção , Proteínas do Core Viral/genética
5.
Zhonghua Gan Zang Bing Za Zhi ; 18(10): 731-4, 2010 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-21059287

RESUMO

OBJECTIVE: We studied the function of dendritic cells subsets and the cytokines levels in plasma in patients with different periods of returning (immune tolerance, hepatitis active and non-replicating period) and aimed to explore the possible reasons for HBV chronic infection. METHODS: Thirty HBV infected patients in different stages of infection were enrolled and divided into three groups: the immune tolerance group (10 cases), the hepatitis active group (10 cases), and the non-replicating group (10 cases). Ten healthy people were enrolled and served as controls. Blood from the patients and controls were collected and the dendritic cells subsets function (The cytokine levels in different groups) were analyzed using statistical method. RESULTS: The total IL-12 output and single nucleus IL-12 output of the total HBV infected patients were lower than that of the healthy control group (P value less than 0.01). The total IFNa output and single nucleus IFNa output of the total HBV infected patients had no significant difference between the total HBV infected patients and the healthy controls (P value more than 0.05). The total IL-12 output of the healthy control group was higher than that in others 3 groups of the HBV infected patients. (Z = -3.039, -2.967 ,-2.949, P value less than 0.01) and the single nucleus IL-12 output of the healthy control group was also higher than that in others 3 groups of the HBV infected patients. (Z =-3.027, -2.671 , -2.863, P value less than 0.01) . The total IFNa output and the single nucleus IFNa output of the healthy control group was higher than that in the hepatitis active group of HBV infected patients (Z = -3.016, -3.176, P value less than 0.01). While the plasma IFNa cytokine levels in the 3 HBV infection groups were higher than in the healthy control group (Z = -2.967, -2.896, -3.054, P value less than 0.01). CONCLUSION: Difference existed between the function of dendritic cells subsets and the IFNa levels in different returning periods of HBV infected patients. The function of dendritic cells subsets has no significant difference in HBV patients with different periods of returning. The flawed function of dendritic cells subsets and the abnormal IFNa level may be one of the reasons for chronic HBV infection.


Assuntos
Células Dendríticas/imunologia , Hepatite B Crônica/imunologia , Hepatite B/imunologia , Interferon-alfa/sangue , Interleucina-12/sangue , Adulto , Estudos de Casos e Controles , Citocinas , Feminino , Hepatite B/sangue , Hepatite B Crônica/sangue , Humanos , Tolerância Imunológica , Masculino , Adulto Jovem
6.
J Phys Chem A ; 114(46): 12237-43, 2010 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-21028770

RESUMO

We present here a study of the phase behavior of mixed component NaNO(3)-Na(2)SO(4) (SNS) droplets with NaNO(3) to Na(2)SO(4) molar ratios of 1:1, 3:1, and 10:1, comparing observations with thermodynamic predictions. Measurements are made by Fourier transform infrared attenuated total reflection and micro-Raman spectroscopy for SNS droplets deposited on ZnSe and quartz substrates, respectively. The conventional deliquescence/efflorescence hysteresis in phase behavior is observed. On drying, heterogeneous crystallization leads to phase behavior that is consistent with bulk solution thermodynamics, with the formation of the mixed salt NaNO(3)·Na(2)SO(4)·H(2)O, Na(2)SO(4) (s), and NaNO(3) (s) all observed to form at relative humidities that coincide with predictions by the aerosol inorganics model. However, conditioning of the droplet at high relative humidity prior to drying is observed to lead to quantitative differences between the fractions of different salts formed. When substrate effects do not influence the crystallization process, supersaturated solutions are formed, and this leads to the observation of contact ion pairs. Such measurements of the phase behavior of mixed component droplets are important for testing the reliability of thermodynamic models.

7.
J Chem Phys ; 129(10): 104509, 2008 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-19044926

RESUMO

The NaNO(3) droplets with sizes of 1-5 microm generated from a nebulizer were deposited on a ZnSe substrate in a Fourier transform infrared attenuated total reflection (FTIR-ATR) chamber. After solidification of the droplets with dry N(2) gas passing through the chamber, the solid NaNO(3) particles were monitored by in situ FTIR-ATR spectra in cycles of deliquescence and efflorescence processes with varying relative humidities (RHs). With an increase in the RH, a dominant peak at approximately 3539 cm(-1), together with three relatively weak peaks at approximately 3400, approximately 3272, and approximately 3167 cm(-1), in the O-H stretching band of water was resolved by the high signal-to-noise ratio FTIR-ATR spectra. The dominant peak and the three relatively weak peaks were contributed by the water monomers and the aggregated water molecules adsorbed on the surfaces of solid NaNO(3) particles, respectively. When the RH approached approximately 72%, slightly lower than the deliquescence RH (74.5%), the band component at approximately 3400 cm(-1) became the main peak, indicating that the water monomers and the aggregated water molecules aggregated to form a thin water layer on the surfaces of solid NaNO(3) particles. A splitting of the nu(3)-NO(3)(-) band at 1363 and 1390 cm(-1) at the RH of approximately 72%, instead of the single nu(3)-NO(3)(-) band at 1357 cm(-1) for the initial solid NaNO(3), was observed. We suggested that this reflected a phase transition from the initial solid to a metastable solid phase of NaNO(3). The metastable solid phase deliquesced completely in the region from approximately 87% to approximately 96% RH according to the fact that the nu(3)-NO(3)(-) band showed two overlapping peaks at 1348 and 1405 cm(-1) similar to those of bulk NaNO(3) solutions. In the efflorescence process of the NaNO(3) droplets, the nu(1)-NO(3)(-) band presented a continuous blueshift from 1049 cm(-1) at approximately 77% RH to 1055 cm(-1) at approximately 36% RH, indicating the formation of contact ion pairs between Na(+) and NO(3)(-). Moreover, in the RH range from approximately 53% down to approximately 26%, two peaks at 836 and 829 cm(-1) were observed in the nu(2)-NO(3)(-) band region, demonstrating the coexistence of NaNO(3) solid particles and droplets.


Assuntos
Nitratos/química , Transição de Fase , Água/química , Compostos de Cádmio/química , Compostos de Mercúrio/química , Nitrogênio/química , Compostos de Selênio/química , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Volatilização , Molhabilidade , Compostos de Zinco/química
8.
Zhonghua Gan Zang Bing Za Zhi ; 16(12): 893-6, 2008 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-19105931

RESUMO

OBJECTIVE: To study the quantities of myeloid and plasmacytoid dendritic cell (mDC, pDC) subsets associated with different blood virus loads (HBV DNA) in patients in different periods of HBV infection (immune tolerance, immune activities and non-replicating periods). METHODS: Thirty HBV infected patients in different stages of infection were enrolled. They were divided into three groups: an immune tolerance group (10 cases), an immunization activities group (10 cases), and a non-replication group (10 cases). Ten healthy people were enrolled and served as controls. Blood (10 ml) from the patients and the controls were collected and the numbers of dendritic cells (DC) in percentage were counted using flow cytometry. The numbers of mDC and pDC were counted and the relevance of them with their blood virus loads (HBV DNA) was analyzed using statistical methods. RESULTS: (1) Absolute values of mDC, pDC percentage and pDC absolute value of the HBV infected patients were lower than those of the healthy control group (P less than 0.05). mDC percentage of the HBV infected patients was a little lower than that of the healthy controls but of no statistical significance (P more than 0.05). (2) The percentage of mDC in the healthy controls was higher than that in the tolerance group (P less than 0.05) and its absolute value in the healthy control group was higher than those in the immune tolerance group and the immune activities group (P less than 0.05). pDC percentage of the healthy control group was higher than those of the immune activities and non-reproduction groups (P less than 0.05). pDC absolute value of the healthy control group was higher than those of the immune tolerance, immune activities and non-reproduction groups (P less than 0.05). (3) The pDC counts in the tolerance group were negatively correlated with HBV DNA levels (r = -0.686, P less than 0.05). CONCLUSIONS: (1) DC frequency and counts of HBV infected patients in different periods decreased. The immune active group decreased significantly more than the healthy control group (P less than 0.05). (2) pDC counts show a negative correlation with HBV DNA levels in only the tolerance group.


Assuntos
Células Dendríticas , Hepatite B/imunologia , Adulto , Estudos de Casos e Controles , Contagem de Células , DNA Viral/sangue , Feminino , Citometria de Fluxo , Hepatite B/sangue , Humanos , Masculino , Carga Viral , Adulto Jovem
9.
J Phys Chem B ; 112(16): 5032-8, 2008 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-18380498

RESUMO

Individual Mg(NO3)2 aerosol particles deposited on a quartz substrate were investigated by confocal Raman spectroscopy. With decreasing the relative humidity (RH) from 92.0% to 1.8%, Raman spectra were obtained of Mg(NO3)2 droplets with water-to-solute molar ratios (WSRs) from 43.1 to 5.2, as well as of amorphous particles. At WSR < 6.0, contact ion pairs between Mg2+ and NO3(-) occurred abundantly, while at RHs of 2.2% and 1.8% with even lower WSRs, amorphous particles appeared with quasi-lattice structures. Two components, one at 3259.0 cm(-1) (C1) and the other at approximately 3480.0 cm(-1) (C2), were resolved for the water O-H stretching envelope through nonlinear curve fittings. The area ratio of C1 to C2, that is, A1/A2, declined with the decrease of WSR, reflecting the breakage of strong hydrogen bonds induced by the hydration of NO3(-). Curve fittings were also carried out for the water O-H stretching envelope of NaNO3 droplets. The value of A1/A2 for Mg(NO3)2 droplets was always higher than that for NaNO3 droplets at the same WSR, indicating a much stronger "structure-making" effect of Mg2+ than of Na+. In the efflorescence process, aerosol particles followed different paths of phase transition from droplets to Mg(NO3)2.6H2O or amorphous states. Reversing somewhat the phase transitions in the efflorescence process, aerosol particles dissolved into droplets with the increase of RH in the deliquescence process. Heterogeneous particles prepared by dehydrating Mg(NO3)2.6H2O were investigated by the depth profiling technique. About 15 h later, the main body of particles changed into Mg(NO3)2.2H2O, a small quantity of Mg(NO3)2.6H2O scattered around particle edges, and some particles were in amorphous states. About 10 days later, a new solid phase occurred on particle surfaces, while the interiors were still Mg(NO3)2.2H2O. With increasing the RH to approximately 11%, significant Mg(NO3)2.6H2O formed on particle surfaces, covering the interior Mg(NO3)2.2H2O.


Assuntos
Compostos de Magnésio/química , Nitratos/química , Transição de Fase , Quartzo/química , Análise Espectral Raman/instrumentação , Análise Espectral Raman/métodos , Aerossóis/química , Hidrogênio/química , Oxigênio/química
10.
Environ Sci Technol ; 42(23): 8698-702, 2008 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-19192784

RESUMO

We report on the investigation of the phase separation of individual seawater droplets in the efflorescence processes with the spatially resolved Raman system. Upon decreasing the relative humidity (RH), CaSO4.0.5H2O separated out foremost fromthe droplet atan unexpectedly high RH of approcimately 90%. Occasionally, CaSO4.2H2O substituted for CaSO4.O.5H2O crystallizing first at approximately 78% RH. Relatively large NaCI solids followed to crystallize at approximately 55% RH and led to the great loss of the solution. Then, the KMgCl3.6H2O crystallites separated out from the residual solutions, adjacentto NaCl at approximately 44% RH. Moreover, a shell structure of dried sea salt particle was found to form at low RHs, with the NaCl crystals in the core and minor supersaturated solutions covered with MgSO4 gel coating on the surface. Ultimately, the shielded solution partly effloresced into MgSO4 hydrates at very dry state (<5% RH).


Assuntos
Transição de Fase , Água do Mar/química , Cloreto de Sódio/química , Análise Espectral Raman , Aerossóis , Sulfato de Cálcio/química , Precipitação Química , Cristalização , Umidade , Soluções
11.
Zhonghua Gan Zang Bing Za Zhi ; 15(11): 809-11, 2007 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-18073061

RESUMO

OBJECTIVE: To observe the anti-viral therapy effect on HBV reactivation in malignant tumor patients and hepatitis B virus carriers after their cancer chemotherapy. METHODS: Thirteen cancer patients but also chronic hepatitis B virus carriers were enrolled in this study. They were randomly put into two groups. Eight patients were put in the therapeutic group. They all had abnormal liver functions induced by the reactivation of HBV after their cancer chemotherapy. Then they were treated with lamivudine. The other 5 cases were treated with lamivudine before their cancer chemotherapy when their serum HBV DNA levels were less than 10(3) copies/ml (preventive therapeutic group). The two groups were followed-up with liver function tests and serum HBV DNA level measurements. RESULTS: Among the 8 cases of the therapeutic group, 5 cases died of liver failure; cancer chemotherapy was postponed or even terminated in 3 patients due to liver function abnormality and anti-virus treatment was started. In the preventive therapy group, no HBV reactivation was observed in any of the 5 cases. CONCLUSION: For HBV carrier cancer patients, an anti-viral therapy before their cancer chemotherapy seems to be very important.


Assuntos
Vírus da Hepatite B , Hepatite B/virologia , Neoplasias/virologia , Ativação Viral/efeitos dos fármacos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Antivirais/uso terapêutico , Portador Sadio/virologia , Feminino , Vírus da Hepatite B/efeitos dos fármacos , Humanos , Lamivudina/uso terapêutico , Masculino , Neoplasias/tratamento farmacológico
12.
J Phys Chem B ; 111(42): 12170-6, 2007 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-17918878

RESUMO

High signal-to-noise ratio (S/N) Raman spectra of (NH(4))(2)SO(4) droplets deposited on a quartz substrate were obtained from dilute to supersaturated states upon decreasing the relative humidity (RH). When the molar water-to-solute ratio (WSR) decreases from 16.8 to 3.2, the v(1)-SO(4)(2-) band changes very little, that is, showing a red-shift of only about 1 cm(-1) (from 979.9 to 978.8 cm(-1)) and an increase of its full width at half-maximum (fwhm) from 8.3 to 9.8 cm(-1). Other vibration modes such as v(2)- and v(4)-SO(4)(2-) bands appear almost constantly at 452 and 615 cm(-1). Such kind of a spectroscopic characteristic is different from previous observation on other cations, indicating that the interactions between SO(4)(2-) and NH(4)+ in supersaturated states are similar to those between SO(4)(2-) and H(2)O in dilute states. After fitting the Raman spectra with Gaussian functions in the spectral range of 2400-4000 cm(-1), we successfully extracted six components at positions of 2878.7, 3032.1, 3115.0, 3248.9, 3468.4, and 3628.8 cm(-1), respectively. The first three components are assigned to the second overtone of NH(4)+ umbrella bending, the combination band of NH(4)+ umbrella bending and rocking vibrations, and the NH(4)+ symmetric stretching vibration, while the latter three components are from the strongly, weakly, and slightly hydrogen-bonded components of water molecules, respectively. With a decrease of the RH, the proportion of the strongly hydrogen-bonded components increases, while that of the weakly hydrogen-bonded components decreases in the droplets. The coexistence of strongly, weakly, and slightly hydrogen-bonded water molecules must hint at a similar hydrogen-bonding network of NH(4)+, SO(4)(2-), and H(2)O to that of pure liquid water in supersaturated (NH(4))(2)SO(4) droplets.

13.
J Phys Chem B ; 110(49): 24993-8, 2006 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-17149921

RESUMO

Confocal Raman spectroscopy was used to study the structural changes of bulk NaNO3 solutions with molar water-to-solute ratios (WSRs) of 54.0-12.3 and NaNO3 droplets (10-100 microm) with WSRs of 9.5-1.0 on a quartz substrate. Upon reduction of the WSR, a blue shift of the symmetric stretching band (nu(1)(NO3-)) from approximately 1048 to approximately 1058 cm(-1) was observed in the confocal Raman spectra with high signal-to-noise ratios. Accordingly, the full width at half-height of the nu(1)(NO3-) band increased from approximately 8.4 cm-1 for the dilute solution (WSR = 54.0) to approximately 15.6 cm-1 for the extremely supersaturated droplet (WSR = 1.0), suggesting the formation of contact ion pairs with different structures. For the O-H stretching band, the ratio of weak hydrogen-bonding components to strong ones, i.e., I(3488)/I(3256), increased from approximately 1.2 at WSR = 54.0 to approximately 7.3 at WSR = 1.0, indicating that the strong hydrogen bonds were heavily destroyed between water molecules especially in the supersaturated droplets. In the humidifying process, two hygroscopic behaviors were observed depending on the morphology of solid NaNO3 particles. No surface water was detected for a solid NaNO3 particle with rhombohedral shape at relative humidities (RHs) below 86%. When the RH increased from 86% to 93%, it suddenly absorbed water and turned into a solution droplet. For a maple-leaf-shaped NaNO3 particle with a rough surface, however, a trace of residual water originally remained on the rough surface even at very low RH according to its Raman spectrum. Its initial water uptake from the ambient occurred at approximately 70% RH. The small amount of initially adsorbed water induced surface rearrangement of the maple-leaf-shaped particle. A further increase of RH made the particle gradually turn into a regular solid core swathed in a solution layer. Eventually, it completely deliquesced in the RH region of 86-93%, similar to the case of the NaNO3 particle with rhombohedral shape.

14.
Zhonghua Yu Fang Yi Xue Za Zhi ; 37(4): 233-5, 2003 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-12930669

RESUMO

OBJECTIVE: To explore the effect of glucocorticoid in the treatment for severe acute respiratory syndrome (SARS). METHODS: Clinical data of 70 patients with SARS admitted to Youan Hospital in Beijing during March to May, 2003 were analyzed. RESULTS: (1) Sixty-three of 70 cases of SARS recovered and seven cases died, with a case-fatality ratio of 10%. (2) Average length of hospital stay was 16.9 days for the all 70 cases, and 16.8 days for the 11 cases without glucocorticoid treatment, without statistical significance (F = 1.018, P = 0.39). (3) The other 59 cases were administered with 40 mg to 640 mg of methylprednisolone daily. (4) Average hospital stay was 15 days for the 23 cases with lower dose of 40 mg to 80 mg methylprednisolone daily, 18.5 days for the 27 cases with medium dose of 120 mg to 240 mg daily, and 17.9 days for the nine cases with higher dose of 320 mg to 640 mg daily (F = 1.018, P = 0.39). CONCLUSIONS: Earlier use of glucocorticoid therapy with suitable doses could alleviate their clinical symptoms, improve their clinical courses, and promote the absorbance of infiltration in their lungs on chest-X-ray films for the cases with SARS. However, current clinical data showed that glucocorticoid therapy could not shorten the length of hospitalization for the cases with SARS.


Assuntos
Anti-Inflamatórios/administração & dosagem , Metilprednisolona/administração & dosagem , Síndrome Respiratória Aguda Grave/tratamento farmacológico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Infusões Intravenosas , Tempo de Internação , Masculino , Metilprednisolona/efeitos adversos , Pessoa de Meia-Idade , Fatores de Tempo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA