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1.
BMC Pulm Med ; 24(1): 471, 2024 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-39334060

RESUMO

BACKGROUND: Acute respiratory distress syndrome (ARDS) is a life-threatening condition frequently encountered in critically ill patients, including those with advanced non-small cell lung cancer (NSCLC). Almonertinib, a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), has shown promise as a first-line treatment for NSCLC with classical EGFR mutations. However, its efficacy in NSCLC patients suffering from ARDS has not been well-documented. CASE PRESENTATION: We report the case of a 63-year-old Chinese Han female with severe NSCLC complicated by ARDS. Upon hospital admission, the patient exhibited progressive dyspnea and required intubation to maintain oxygenation. Pathological analysis of bronchoalveolar lavage fluid sediment confirmed lung adenocarcinoma, and genetic testing of blood identified an EGFR E19 mutation. The patient was treated with almonertinib, resulting in significant clinical improvement and successful extubation after nine days. Radiographic imaging showed substantial reduction in pulmonary lesions, highlighting the efficacy of almonertinib. CONCLUSION: This case represents the first documented successful treatment of ARDS induced by EGFR E19 mutated NSCLC using almonertinib. The favorable clinical response observed in this critically ill patient suggests that almonertinib may be a viable therapeutic option for managing severe complications in NSCLC. Further research is necessary to corroborate these findings and optimize dosage and toxicity management strategies for broader clinical application.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Receptores ErbB , Neoplasias Pulmonares , Síndrome do Desconforto Respiratório , Humanos , Feminino , Pessoa de Meia-Idade , Síndrome do Desconforto Respiratório/tratamento farmacológico , Síndrome do Desconforto Respiratório/etiologia , Receptores ErbB/genética , Receptores ErbB/antagonistas & inibidores , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/complicações , Neoplasias Pulmonares/patologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/complicações , Mutação , Inibidores de Proteínas Quinases/uso terapêutico , Acrilamidas/uso terapêutico , Resultado do Tratamento , Tomografia Computadorizada por Raios X
2.
Ecotoxicol Environ Saf ; 286: 117215, 2024 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-39427537

RESUMO

Nanoparticles (NPs) have achieved extensive utilization across diverse domains, highlighting their unavoidable impact on health. The internalization of NPs carries the potential to trigger inflammation and instigate ailments by selectively targeting lysosomes, thereby posing significant public health concern. Lysosomes, essential organelles responsible for the degradation of biological macromolecules within cells, are crucial for cellular homeostasis and participate in key biological processes, including inter-organelle communication, signal transduction, plasma membrane repair, and immune responses. Consequently, a thorough understanding of lysosomal function is essential for elucidating the mechanisms underlying NPs-mediated toxicity. NPs-induced lysosomal dysfunction primarily involves disruptions in the acidic microenvironment of lysosomes, lysosomal membrane rupture, and membrane permeabilization. Additionally, potential molecular mechanisms contributing to the increased risk of lysosomal damage caused by NPs have been described, particularly concerning ion channel proteins such as V-ATPase, TRPM2, CLC-7, and LAMPs. This review aims to detail the alterations in lysosomal functionality induced by NPs and their associated mechanisms. By providing a theoretical framework, this review aims to support the potential application of NPs in biomedical fields.

3.
Front Med (Lausanne) ; 11: 1420473, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38882665

RESUMO

Background: Renal arteriovenous malformations (rAVMs) are congenital abnormal pathways between renal arteries and veins that are rare in the general population. It is often misdiagnosed as malignant renal tumors with abundant blood supply, and the definitive diagnosis primarily relies on angiography. Multimodality imaging, including contrast-enhanced computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT plays an important role in the differential diagnosis of renal space-occupying lesions. Case presentation: A 56-year-old man presented with abdominal distension, loss of appetite, and back pain without obvious cause 2 years ago, without nausea vomiting, or frequent urination. Gastroscopy and colonoscopy showed multiple polyps in the duodenum and colon. Abdomen contrast-enhanced CT revealed a mass of 1.6 × 1.4 cm in the left kidney, which was considered to be a malignant tumor. PET/CT was performed for further diagnosis; the 18F-fluorodesoxyglucose (18F-FDG) PET/CT scan showed mild uptake in the left renal mass, while no uptake of 18F- prostate-specific membrane antigen (PSMA) was observed. Following a multidisciplinary discussion, the possibility of renal AVMs was considered and subsequently confirmed by renal angiography as the diagnosis. Then, selective segmental renal artery embolization was performed for treatment. Conclusion: Renal AVMs are extremely rare in clinical practice. Due to limited research on the application of 18F-FDG and 18F-PSMA PET/CT to renal AVMs, its role remains largely unexplored. With the increasing popularity of PET/CT imaging, comprehensive imaging of the disease has become indispensable. We report the first case of PSMA PET/CT imaging in renal AVMs, and when PSMA expression is absent in a renal mass, the possibility of renal AVMs should be considered.

4.
Front Oncol ; 14: 1401453, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39077465

RESUMO

We herein describe a rare case of adult acute lymphoblastic leukemia with an 18florine-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) skeletal superscan-like appearance. The degree of bone marrow uptake was so intense that it far exceeded the level of physiological cerebral uptake and radiourinary activity. The distribution was remarkably similar to a superscan seen on skeletal scintigraphy. Skeletal superscans of 18F-FDG PET/CT have been reported in hematological diseases, solid tumors with extensive bone metastasis, and metabolic diseases. Thus, we reviewed the PET/CT images of cases reported, indicating that more homogeneous distribution, without primary tumor and specific mandibular and skull activity, may be suggestive of hematological diseases.

5.
Front Microbiol ; 15: 1344344, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38585694

RESUMO

Porcine epidemic diarrhea virus (PEDV) is an acute, highly contagious enterovirus that infects pigs of all ages. The B cells are important for antigen presentation, antibody production, and cytokine secretion to resist infection. However, the role of B cells in PEDV infection remains unclear. In this study, the effects of PEDV virulent (QY2016) and attenuated strains (CV777) on B cells sorted from neonatal piglets, nursery piglets, and gilts were investigated. The results showed that PEDV-QY2016 and PEDV-CV777 could significantly increase the expression of CD54 and CD27 in B cells from neonatal piglets. The percentages of CD80, MHC II, and IgM expressed on neonatal piglet B cells infected with PEDV-QY2016 were significantly lower than those expressed on the B cells infected with PEDV-CV777. Both PEDV-QY2016 and PEDV-CV777 could stimulate IFN-α and GM-CSF secretions in neonatal piglet B cells; IL-1, IFN-α, and IL-4 secretion in nursery piglet B cells; and IL-1, TGF-ß secretion, and GM-CSF in gilt B cells. Furthermore, both PEDV-QY2016 and PEDV-CV777 could induce the secretion of IgA, IgM, and IgG in nursery piglet B cells but could not induce the secretion of IgA, IgM, and IgG in neonatal piglet B cells. The secretion of IgA, IgM, and IgG was significantly higher by the PEDV-CV777 strains infected B cells than those by the PEDV-QY2016 strains infected gilt B cells. In conclusion, the surface molecule expression, cytokine secretion, and antibody production of B cells induced by PEDV are closely related to the ages of pigs and the virulence of the PEDV strain.

6.
Sci Total Environ ; 929: 172652, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38653146

RESUMO

Airway epithelium is extraordinary vulnerable to damage owning to continuous environment exposure. Subsequent repair is therefore essential to restore the homeostasis of respiratory system. Disruptions in respiratory epithelial repair caused by nanoparticles exposure have been linked to various human diseases, yet implications in repair process remain incompletely elucidated. This study aims to elucidate the key stage in epithelial repair disturbed by carbon black (CB) nanoparticles, highlighting the pivotal role of ΔNp63 in mediating the epithelium repair. A competitive-like binding between CB and beta-catenin 1 (CTNNB1) to ΔNp63 is proposed to elaborate the underlying toxicity mechanism. Specifically, CB exhibits a remarkable inhibitory effect on cell proliferation, leading to aberrant airway epithelial repair, as validated in air-liquid culture. ΔNp63 drives efficient epithelial proliferation during CB exposure, and CTNNB1 was identified as a target of ΔNp63 by bioinformatics analysis. Further molecular dynamics simulation reveals that oxygen-containing functional groups on CB disrupt the native interaction of CTNNB1 with ΔNp63 through competitive-like binding pattern. This process modulates CTNNB1 expression, ultimately restraining proliferation during respiratory epithelial repair. Overall, the current study elucidates that the diminished interaction between CTNNB1 and ΔNp63 impedes respiratory epithelial repair in response to CB exposure, thereby enriching the public health risk assessment on CB-related respiratory diseases.


Assuntos
Fuligem , beta Catenina , Fuligem/toxicidade , beta Catenina/metabolismo , Humanos , Mucosa Respiratória , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Proliferação de Células , Células Epiteliais , Nanopartículas/toxicidade
7.
Heliyon ; 10(11): e31710, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38882295

RESUMO

Hyperlipidemia refers to the abnormal levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL-C) and high-density lipoprotein (HDL-C) in peripheral blood circulation. It is a predominant risk factor underlying cardiovascular and cerebrovascular diseases, including coronary heart disease and atherosclerosis. Furthermore, it is also one of the most prevalent chronic diseases globally. Liujunzi Decoction is the basic prescription for the treatment of spleen and stomach diseases. It can tonify the spleen and qi, remove dampness, and reduce turbidity. Moreover, it is also clinically used for the treatment of spleen deficiency hyperlipidemia. However, its metabolites and therapeutic effect on spleen deficiency hyperlipidemia have not been comprehensively determined in vitro and in vivo. This study established a rat model of spleen deficiency hyperlipidemia by inducing starvation and satiety disorders, exhaustion swimming, and intragastric administration of the fat emulsion. To identify related metabolite changes and serum lipid composition, UPLC-Q-TOF-MS, PCA, and OPLS-DA lipidological methods were performed. The results demonstrated significant changes in rat's signs during the modeling process, which were consistent with the criteria for the syndrome differentiation of spleen deficiency in traditional Chinese medicine. Furthermore, this study identified 100 potential biomarkers in rat serum, of which 52 were associated with lipid synthesis, such as LPC, PC, PI, PE, PA, Cer, SM, etc. The pathways involved were glycerol phospholipid, sphingomyelin, and glycerol ester metabolisms. After the Liujunzi decoction intervention, 56 potential biomarkers were observed in the high-dose group, alleviating the metabolic spectrum imbalance by reducing metabolite levels. In addition, metabolic pathway disturbances were markedly improved. This study provides references for future studies on Liujunzi decoction and furnishes essential data for assessing the relationships between chemical constituents and pharmacological activities of Liujunzi decoction.

8.
Int J Biol Macromol ; 263(Pt 2): 130335, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38403215

RESUMO

The electrospinning technology has set off a tide and given rise to the attention of a widespread range of research territories, benefiting from the enhancement of nanofibers which made a spurt of progress. Nanofibers, continuously produced via electrospinning technology, have greater specific surface area and higher porosity and play a non-substitutable key role in many fields. Combined with the degradability and compatibility of the natural structure characteristics of polysaccharides, electrospun polysaccharide nanofiber membranes gradually infiltrate into the life field to help filter air contamination particles and water pollutants, treat wounds, keep food fresh, monitor electronic equipment, etc., thus improving the life quality. Compared with the evaluation of polysaccharide-based nanofiber membranes in a specific field, this paper comprehensively summarized the existing electrospinning technology and focused on the latest research progress about the application of polysaccharide-based nanofiber in different fields, represented by starch, chitosan, and cellulose. Finally, the benefits and defects of electrospun are discussed in brief, and the prospects for broadening the application of polysaccharide nanofiber membranes are presented for the glorious expectation dedicated to the progress of the eras.


Assuntos
Quitosana , Nanofibras , Nanofibras/química , Alicerces Teciduais/química , Polissacarídeos/química , Amido
9.
Nucl Med Commun ; 44(10): 900-909, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37503694

RESUMO

OBJECTIVE: This study aimed to investigate the relationship between 18 F-fluorodeoxyglucose PET/computed tomography ( 18 F-FDG PET/CT) metabolic parameters and clinical benefit and prognosis in nonsmall cell lung cancer (NSCLC). METHODS: In total, 34 advanced NSCLC patients who received 18 F-FDG PET/CT before immunotherapy were retrospectively included in this study. All patients were divided into two groups, the clinical benefit (CB) group and the no-clinical benefit (no-CB) group, based on the efficacy of evaluation after 6 months of treatment. Also clinical information, characteristics of metastases, survival, PD-L1 expression level and glucose metabolic parameters were evaluated. RESULTS: Finally, 24 patients were in the CB group, and 10 patients were in the no-CB group. There was a significant difference between the CB group and the no-CB group in TNM stages ( P = 0.005), visceral and bone metastasis ( P = 0.031), metabolic tumor volume of primary lesion (MTV-P; P = 0.003), the metabolic tumor volume of whole-body (MTVwb; P = 0.005) and total lesion glycolysis of whole-body (TLGwb, P = 0.015). However, for patient outcomes, the independent prognostic factors associated with progression free survival were TNM stage (HR = 0.113; 95% CI, 0.029-0.439; P = 0.002), TLG-P (HR = 0.085; 95% CI, 0.018-0.402; P = 0.002) and TLG-LN (HR = 0.068; 95% CI, 0.015-0.308; P = 0.000), and the TLG-LN (HR = 0.242; 95% CI, 0.066-0.879; P = 0.002) was the independent prognostic factor associated with overall survival. CONCLUSIONS: Metastatic lesion burden evaluated by 18 F-FDG PET/ CT can predict response to immunotherapy in advanced NSCLC patients, in which lymph node metastasis lesion metabolic burden is a meaningful predictor, but a large multicenter trial is still needed to validate this conclusion.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Carcinoma Pulmonar de Células não Pequenas/terapia , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Fluordesoxiglucose F18/metabolismo , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/terapia , Neoplasias Pulmonares/metabolismo , Estudos Retrospectivos , Prognóstico , Imunoterapia , Carga Tumoral , Compostos Radiofarmacêuticos
10.
J Cardiothorac Surg ; 18(1): 171, 2023 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-37138316

RESUMO

BACKGROUND: An ectopic meningioma, such as a primary pulmonary meningioma (PPM), is a rare type of tumor that primarily originates outside of the central nervous system. The most common presentation of PPM is isolated pulmonary nodules or masses, and most of them are benign. Only sporadic cases have been reported. This case reported a giant primary pulmonary meningioma and systematically reviewed previously reported cases in the literature. CASE PRESENTATION: A 55-year-old female suffered from asthma after activity, chest tightness, and a persistent dry cough for 2 months. Chest computed tomography (CT) showed a huge mass with calcification in the left lower lobe. And positron emission tomography (PET)/CT revealed mild FDG accumulation of the mass. The mass was finally surgically removed and PPM was confirmed according to histopathologic examinations. CONCLUSION: PPM is a rare disease with heterogeneity not only in CT features but also in glucose metabolism. FDG uptake levels do not identify benign from malignant, benign PPM may have high FDG uptake and malignant may have low.


Assuntos
Neoplasias Encefálicas , Neoplasias Meníngeas , Meningioma , Feminino , Humanos , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Fluordesoxiglucose F18 , Meningioma/diagnóstico por imagem , Meningioma/cirurgia , Compostos Radiofarmacêuticos , Neoplasias Meníngeas/diagnóstico por imagem , Neoplasias Meníngeas/cirurgia , Tomografia por Emissão de Pósitrons/métodos
11.
Abdom Radiol (NY) ; 48(11): 3449-3457, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37493838

RESUMO

PURPOSE: To evaluate the diagnostic value of serum CA125 combined with 18F-FDG PET/CT in ovarian cancer (OC) and tuberculous peritonitis (TBP) in female patients and to establish a diagnostic scoring system. METHOD: A total of 86 female patients (64 OC and 22 TBP) were included in this study. Serum CA125, PET/CT maximal intensity projection (MIP), maximal standardized uptake value, ovarian mass, ascites volume, and other indicators were analyzed and a diagnostic scoring system was established according to the weights of statistically significant indicators. RESULTS: Univariate analysis showed that serum CA125 in OC and TBP patients were 2079.9 ± 1651.3 U/mL and 448.3 ± 349.5 U/mL (P < 0.001). In MIP images, abdominal lesions were focal distribution in 92.2% (59/64) of OC patients and diffuse distribution in 95.5% (21/22) of TBP patients (P < 0.001). Ovarian masses could be observed in 82.8% (53/64) OC patients and 31.8% (7/22) TBP patients (P <0.001). The other indicators were not statistically significant. Logistic regression analysis showed that serum CA125 and MIP were independent risk factors for diagnosis. A diagnostic scoring system could be established based on serum CA125, MIP and ovarian mass, and the diagnostic sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 98.4% (63/64), 95.5% (21/22), 97.7% (84/86), 98.4% (63/64), and 95.5% (21/22), respectively. CONCLUSION: Serum CA125 combined with PET/CT is of great value in the diagnosis of OC and TBP. A simple and efficient diagnostic scoring system can be established using serum CA125, MIP image feature, and ovarian mass.

12.
Med Educ Online ; 27(1): 2093427, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35747998

RESUMO

Depression is common worldwide, and stigmatizing attitudes toward depression have proved to be one of the major barriers to seeking professional help. The purpose of this study was to evaluate the level of personal depression stigma and identify its predictive factors among medical students in Hainan, China, as well as explore the gender difference. A total of 2,186 medical students were recruited using stratified random cluster sampling and interviewed by structured anonymous questionnaires. Personal stigma was measured by the standardized Depression Stigma Scale (DSS). Multivariate linear regression models were used to identify predictors of stigma, and the interactions between gender and each predictor were included to test its gender difference. The mean score on DSS Scale was 13.71 ± 5.35, with males significantly higher than females (14.85 vs 12.99, P < 0.0001). Compared to females, males were more likely to agree with 'I would not vote for a class cadre if I knew they had been depressed' and 'I would not make friends with him if I knew he had been depressed'. Multivariate linear regression analysis revealed that males' personal stigma was predicted by being only child (ß = 1.01, P = 0.0083), moderate-to-severe depression (ß = 1.12, P = 0.0302), and lower self-rated academic core competitiveness (Competitive: ß = 1.29, P = 0.0088, Not at all/Somewhat competitive: ß = 1.04, P = 0.0381), while females' personal stigma was only associated with moderate-to-severe depression (ß = 1.75, P < 0.0001). Significant interactions were found between gender and self-rated academic core competitiveness. Stigmatizing attitudes toward depression were prevalent among Chinese medical students, especially male students. Gender differences were found in the predictors of stigma. Effective measures must be taken to reduce the stigma of mental health among Chinese medical students.


Assuntos
Estudantes de Medicina , Adulto , China , Depressão/epidemiologia , Feminino , Humanos , Masculino , Saúde Mental , Estigma Social , Inquéritos e Questionários
13.
J Leukoc Biol ; 111(1): 19-32, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34448502

RESUMO

Neuroblastoma (NB) is a huge threat to children's health. Adipose-derived stem cells-derived extracellular vesicles (ADSC-Evs) can regulate tumor progression. This study aimed to identify the role of ADSC-Evs in NB. Following ADSC-Ev isolation and identification, PKH26-labeled ADSC-Evs were cocultured with NB cells to observe the internalization of ADSC-Evs. ADSC-Ev effects on NB cell proliferation, invasion, and migration were assessed. The regulatory molecules related to NB development were predicted. The expressions of and relations among LINC00622, transcriptional factor androgen receptor (AR), and gamma-aminobutyric acid B-type receptor 1 (GABRR1) were detected and verified. LINC00622 was inhibited in ADSCs to evaluate ADSC-Ev effects on NB cells. Xenograft tumor experiment in nude mice was further performed to evaluate the effects of ADSC-Evs-carried LINC00622 on NB in vivo. ADSC-Evs inhibited NB cell proliferation, invasion, and migration. ADSC-Evs increased GABBR1 expression in NB cells. ADSC-Evs-carried LINC00622 mediated AR to promote GABBR1 expression. Silencing LINC00622 in ADSCs weakened the inhibition of ADSC-Evs on NB cell malignant behaviors. ADSC-Evs reduced tumor growth in nude mice, which was restored after inhibiting LINC00622 expression in ADSCs. We highlighted that ADSC-Evs carried LINC00622 into NB cells to inhibit transcription factor AR and promote GABBR1 expression, thus inhibiting NB cell growth.


Assuntos
Neoplasias Encefálicas/genética , Vesículas Extracelulares/genética , Neuroblastoma/genética , RNA Longo não Codificante/genética , Receptores Androgênicos/genética , Receptores de GABA-B/genética , Animais , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Proliferação de Células , Células Cultivadas , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Camundongos Endogâmicos BALB C , Camundongos Nus , Invasividade Neoplásica/genética , Invasividade Neoplásica/patologia , Neuroblastoma/patologia , Ratos Sprague-Dawley , Fatores de Transcrição/genética
14.
Viruses ; 14(2)2022 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-35215935

RESUMO

Porcine sapelovirus (PSV) is an important emerging pathogen associated with a wide variety of diseases in swine, including acute diarrhoea, respiratory distress, skin lesions, severe neurological disorders, and reproductive failure. Although PSV is widespread, serological assays for field-based epidemiological studies are not yet available. Here, four PSV strains were recovered from diarrheic piglets, and electron microscopy revealed virus particles with a diameter of ~32 nm. Analysis of the entire genome sequence revealed that the genomes of PSV isolates ranged 7569-7572 nucleotides in length. Phylogenetic analysis showed that the isolated viruses were classified together with strains from China. Additionally, monoclonal antibodies for the recombinant PSV-VP1 protein were developed to specifically detect PSV infection in cells, and we demonstrated that isolated PSVs could only replicate in cells of porcine origin. Using recombinant PSV-VP1 protein as the coating antigen, we developed an indirect ELISA for the first time for the detection of PSV antibodies in serum. A total of 516 swine serum samples were tested, and PSV positive rate was 79.3%. The virus isolates, monoclonal antibodies and indirect ELISA developed would be useful for further understanding the pathophysiology of PSV, developing new diagnostic assays, and investigating the epidemiology of the PSV.


Assuntos
Infecções por Picornaviridae/veterinária , Picornaviridae/genética , Picornaviridae/isolamento & purificação , Doenças dos Suínos/virologia , Animais , Anticorpos Antivirais/sangue , Sequência de Bases , China , Fezes/virologia , Variação Genética , Genoma Viral , Filogenia , Picornaviridae/classificação , Picornaviridae/fisiologia , Infecções por Picornaviridae/sangue , Infecções por Picornaviridae/virologia , Suínos , Doenças dos Suínos/sangue , Replicação Viral , Sequenciamento Completo do Genoma
15.
Biochemistry ; 43(34): 10877-85, 2004 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-15323548

RESUMO

Light-induced Fourier transform infrared difference spectroscopy has been applied to studies of ammonia effects on the oxygen-evolving complex (OEC) of photosystem II (PSII). We found that NH(3) induced characteristic spectral changes in the region of the symmetric carboxylate stretching modes (1450-1300 cm(-1)) of the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectra of PSII. The S(2) state carboxylate mode at 1365 cm(-1) in the S(2)Q(A)(-)/S(1)Q(A) spectrum of the controlled samples was very likely upshifted to 1379 cm(-1) in that of NH(3)-treated samples; however, the frequency of the corresponding S(1) carboxylate mode at 1402 cm(-1) in the same spectrum was not significantly affected. These two carboxylate modes have been assigned to a Mn-ligating carboxylate whose coordination mode changes from bridging or chelating to unidentate ligation during the S(1) to S(2) transition [Noguchi, T., Ono, T., and Inoue, Y. (1995) Biochim. Biophys. Acta 1228, 189-200; Kimura, Y., and Ono, T.-A. (2001) Biochemistry 40, 14061-14068]. Therefore, our results show that NH(3) induced significant structural changes of the OEC in the S(2) state. In addition, our results also indicated that the NH(3)-induced spectral changes of the S(2)Q(A)(-)/S(1)Q(A) spectrum of PSII are dependent on the temperature of the FTIR measurement. Among the temperatures we measured, the strongest effect was seen at 250 K, a lesser effect was seen at 225 K, and little or no effect was seen at 200 K. Furthermore, our results also showed that the NH(3) effects on the S(2)Q(A)(-)/S(1)Q(A) spectrum of PSII are dependent on the concentrations of NH(4)Cl. The NH(3)-induced upshift of the 1365 cm(-1) mode is apparent at 5 mM NH(4)Cl and is completely saturated at 100 mM NH(4)Cl concentration. Finally, we found that CH(3)NH(2) has a small but clear effect on the spectral change of the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectrum of PSII. The effects of amines on the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectra (NH(3) > CH(3)NH(2) > AEPD and Tris) are inverse proportional to their size (Tris approximately AEPD > CH(3)NH(2) > NH(3)). Therefore, our results showed that the effects of amines on the S(2)Q(A)(-)/S(1)Q(A) spectrum of PSII are sterically selective for small amines. On the basis of the correlations between the conditions (dependences on the excitation temperature and NH(3) concentration and the steric requirement for the amine effects) that give rise to the NH(3)-induced upshift of the 1365 cm(-)(1) mode in the S(2)Q(A)(-)/S(1)Q(A) spectrum of PSII and the conditions that give rise to the altered S(2) state multiline EPR signal, we propose that the NH(3)-induced upshift of the 1365 cm(-1) mode is caused by the binding of NH(3) to the site on the Mn cluster that gives rise to the altered S(2) state multiline EPR signal. In addition, we found no significant NH(3)-induced change in the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectrum at 200 K. Under this condition, the OEC gives rise to the NH(3)-stabilized g = 4.1 EPR signal and a suppressed g = 2 multiline EPR signal. Our results suggest that the structural difference of the OEC between the normal g = 2 multiline form and the NH(3)-stabilized g = 4.1 form is small.


Assuntos
Amônia/química , Luz , Complexo de Proteína do Fotossistema II/química , Proteínas de Plantas/química , Aminas/química , Benzoquinonas/química , Benzoquinonas/metabolismo , Sítios de Ligação , Catálise , Espectroscopia de Ressonância de Spin Eletrônica , Isomerismo , Oxigênio/química , Oxigênio/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Proteínas de Plantas/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Spinacia oleracea , Temperatura
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