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Thyroid cancer (TC) is the most common endocrine malignancy. Recently, the global incidence of TC has increased rapidly. Differentiated thyroid cancer includes papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC), which are the most common types of TC. Although PTCs and FTCs exert good prognoses and high survival rates, FTCs tend to be more aggressive than PTCs. There is an urgent need to improve patient outcomes by developing effective therapeutic agents for FTCs. Piperlongumine exerts anti-cancer effects in various human carcinomas, including human anaplastic TCs and PTCs. However, the anti-cancer effects of piperlongumine in FTCs and the underlying mechanisms are yet to be elucidated. Therefore, in the present study, we evaluated the effect of piperlongumine on cell proliferation, cell cycle, apoptosis, and autophagy in FTC cells with flowcytometry and Western blot. We observed that piperlongumine caused growth inhibition, cell cycle arrest, apoptosis induction, and autophagy elevation in FTC cells. Activities of reactive oxygen species and the downstream PI3K/Akt pathway were the underlying mechanisms involved in piperlongumine mediated anti-FTC effects. Advancements in our understanding of the effects of piperlongumine in FTC hold promise for the development of novel therapeutic strategies.
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Adenocarcinoma Folicular , Neoplasias de la Tiroides , Humanos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Adenocarcinoma Folicular/patología , Transducción de Señal , Neoplasias de la Tiroides/patología , Apoptosis , AutofagiaRESUMEN
BACKGROUND: The microsurgical treatment of paraclinoid aneurysms can be challenging due to the anatomical structures that surround them. OBJECTIVE: This study compared the clinical and angiographic outcomes of unruptured paraclinoid aneurysms treated with enterprise (EP) stents and low-profile visualized intraluminal support (LVIS) stents. METHODS: A retrospective analysis of the clinical and radiological data from 133 patients with 139 unruptured paraclinoid aneurysms, who received an EP or an LVIS stent between January 2017 and June 2021 at Taizhou People's Hospital, was performed. Immediate postoperative and follow-up angiographic results were analyzed retrospectively using the Raymond-Roy occlusion classification (RROC). Any complications following the procedure and the patients' clinical outcomes were noted. RESULTS: Enterprise stents were used for stent-assisted coiling in 64 patients with 68 aneurysms and LVIS stents were used in 69 patients with 71 aneurysms. Both groups exhibited an increase in the proportion of aneurysms meeting the criteria for RROC class I, but the LVIS group demonstrated a higher rate of aneurysms meeting the class I criteria compared with the EP group, both on immediate postoperative angiography (45.1% vs. 11.8%, p< 0.001) and on follow-up angiography (94.9% vs. 80.6%, p= 0.025). Procedure-related complications were experienced by 9.4% of patients in the EP group (one coil prolapse, two parent artery occlusions, and three thromboembolic events), and 8.7% of patients in the LVIS group (three stent-related thrombosis and three thromboembolic events). There were no statistically significant differences between the two groups in relation to perioperative complications (p= 0.746) or favorable clinical outcomes (p= 0.492). CONCLUSION: A greater proportion of aneurysms in the LVIS group met the criteria for RROC class I compared with the EP group. There is no significant difference in procedural complications or clinical outcomes between EP and LVIS stents. Although no aneurysm recurrence was observed during the short follow-up period, continued monitoring is required.
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Procedimientos Endovasculares , Aneurisma Intracraneal , Humanos , Estudios Retrospectivos , Aneurisma Intracraneal/cirugía , Resultado del Tratamiento , Angiografía Cerebral/métodos , Stents , Procedimientos Endovasculares/métodosRESUMEN
Cyclooxygenase 2 (COX-2) and 5-lipoxygenase (5-LOX) are overexpressed in gastric cancer cells, the dual inhibitors of which exhibit potential against metastasis and invasion with fewer side effects. To discover inhibitors targeting COX-2 and 5-LOX, we conducted ultrafiltration and enrichment calculation to screen candidates in quaternary alkaloids (QAs) from Zanthoxylum simulans through LC and LC-Q-TOF. For intensive peaks, peaks 19 (berberine) and 21 (chelerythrine) were observed as the most potent dual candidates and showed selective affinity to 5-LOX over COX-2. Peak 19 showed an enrichment at 4.36 for COX-2 and 22.81 for 5-LOX, while peak 21 showed an enrichment at 7.81 for COX-2 and 24.49 for 5-LOX. Molecular docking results revealed chelerythrine as a better dual inhibitor, showing time- and dose-dependent anti-proliferation against AGS cells. Bio-informatics strategies, such as Gene Expression Omnibus (GEO), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG), suggested that hormone pathways in gastric cancer cells might be mediated by chelerythrine. Further reviews and summaries helped outline the mechanisms by which COX-2/5-LOX inhibitors might promote apoptosis in gastric cancer cells via estrogen, thyroid, and oxytocin signaling pathways. Chelerythrine was also added to gastric cancer cells to verify the regulation of these three signaling pathways. As a result, significant calling back of thyroid-stimulating hormone receptor (TSHR), thyroid hormone α3 (TRα3), and thyroid hormone receptor ß1 (TRß1) and suppressing estrogen receptor α36 (ER-α36)-Src could benefit the anti-proliferation of chelerythrine. However, it was disappointing that regulation of estrogen receptor α66 (ER-α66), estrogen receptor ß (ER-ß), and oxytocin receptor (OTR) contributed inversely negative effects on anti-gastric cancer cells. At present, the integrative study not only revealed chelerythrine as the most potent dual COX-2/5-LOX inhibitor from QAs but also generally highlighted that comprehensive regulation of the estrogen, thyroid, and oxytocin pathway should be noted once gastric cancer cells were treated with inflammatory inhibitors.
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From November 1,2018 to January 31,2019 (OP2018-2019) and from November 1,2019 to January 20, 2020 (OP2019-2020), PM1 measurement was conducted daily for two consecutive years. The concentration of trace elements in the atmospheric PM1 in Qingdao in autumn and winter was analyzed. The observation period was divided into four air quality levels (Level â , Level â ¡, Level â ¢, and Level â £), and the characteristics and sources of the concentration of trace elements in PM1 were analyzed. The non-carcinogenic risks (Zn, Pb, Mn, Cu, and V) and carcinogenic risks (As, Cr, Ni, Cd, and Co) of different people with different air quality levels were evaluated. The results showed that the changes in total metal element concentrations were associated with changes in Ca, K, and Al concentrations at different air quality classes during OP2019-2020 compared to those during OP2018-2019 and were more influenced by dust and biomass combustion sources. Compared with that during OP2018-2019, the V concentration in different air quality levels (Level â , Level â ¡, Level â ¢, and Level â £) during OP2019-2020 decreased by 19.0%, 60.5%, 82.7%, and 77.5%, respectively. This was presumed to be related to the implementation of the Domestic Emission Control Area (DECA) policy for ships, which led to the significant reduction in V concentration due to the change in fuel quality of ships in the waters around Qingdao. The results of the enrichment factor, the ratio method, and the backward trajectory of airflow further indicated that the changes in V concentrations were mainly influenced by the DECA policy. However, after the implementation of the DECA, the V/Ni value as a limit for judging the influence of ship sources in the area required further exploration. The health risk assessment results showed that the risk factor of Mn ranged from 0.07 to 1.22 during OP2018-2019 and OP2019-2020. It was recommended to strengthen the management and control of Mn-containing pollution sources. The lifetime carcinogenic risk (ILCR) value of As and Cd under different air qualities during OP2018-2019 and OP2019-2020 was lower than 10-4 but higher than 10-6, indicating that there was a carcinogenic probability, although it was still at an acceptable level. During OP2018-2019, when the air quality was â £, the ILCR value of Cr was higher than 10-4, and there was a risk of cancer.
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Contaminantes Atmosféricos , Oligoelementos , Contaminantes Atmosféricos/análisis , Cadmio , Carcinógenos , Monitoreo del Ambiente , Humanos , Medición de Riesgo , Oligoelementos/análisisRESUMEN
Gestational diabetes mellitus (GDM) refers to different degrees of glucose tolerance abnormalities that occur during pregnancy or are discovered for the first time, which can have a serious impact on the mother and the offspring. The screening of GDM mainly relies on the oral glucose tolerance test (OGTT) at 24-28 weeks of gestation. The early diagnosis and intervention of GDM can greatly improve adverse pregnancy outcomes. However, molecular markers for early prediction and diagnosis of GDM are currently lacking. Therefore, looking for GDM-specific early diagnostic markers has important clinical significance for the prevention and treatment of GDM and the management of subsequent maternal health. Circular RNA (circRNA) is a new type of non-coding RNA. Recent studies have found that circRNAs were involved in the occurrence and development of malignant tumors, metabolic diseases, cardiovascular and cerebrovascular diseases, etc., and could be used as the molecular marker for early diagnosis. Our previous research showed that circRNAs are differentially expressed in serum of GDM pregnant women in the second and third trimester, placental tissues during cesarean delivery, and cord blood. However, the mechanism of circular RNA in GDM still remains unclear. This article focuses on related circRNAs involved in insulin resistance and ß-cell dysfunction, speculating on the possible role of circRNAs in the pathophysiology of GDM under the current research context, and has the potential to serve as early molecular markers for the diagnosis of GDM.
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Thyroid cancer (TC) is the most common endocrine malignancy, and its global incidence has steadily increased over the past 15 years. TC is broadly divided into well-differentiated, poorly differentiated, and undifferentiated types, depending on the histological and clinical parameters. Thus far, there are no effective treatments for undifferentiated thyroid cancers or advanced and recurrent cancer. Therefore, the development of an effective therapeutic is urgently needed for such patients. Piperlongumine (PL) is a naturally occurring small molecule derived from long pepper; it is selectively toxic to cancer cells by generating reactive oxygen species (ROS). In this study, we demonstrate the potential anticancer activity of PL in four TC cell lines. For this purpose, we cultured TC cell lines and analyzed the following parameters: Cell viability, colony formation, cell cycle, apoptosis, and cellular ROS induction. PL modulated the cell cycle, induced apoptosis, and suppressed tumorigenesis in TC cell lines in a dose- and time-dependent manner through ROS induction. Meanwhile, an intrinsic caspase-dependent apoptosis pathway was observed in the TC cells under PL treatment. The activation of Erk and the suppression of the Akt/mTOR pathways through ROS induction were seen in cells treated with PL. PL-mediated apoptosis in TC cells was through the ROS-Akt pathway. Finally, the anticancer effect and safety of PL were also demonstrated in vivo. Our findings indicate that PL exhibits antitumor activity and has the potential for use as a chemotherapeutic agent against TC. This is the first study to show the sensitivity of TC cell lines to PL.
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The RNA methyltransferase NSUN2 has been involved in the cell proliferation and senescence, and is upregulated in various types of cancers. However, the role and potential mechanism of NSUN2 in gastric cancer remains to be determined. Our study showed that NSUN2 was significantly upregulated in gastric cancers, compared to adjacent normal gastric tissues. Moreover, NSUN2 could promote gastric cancer cell proliferation both in vitro and in vivo. Further study demonstrated that CDKN1C (p57Kip2) was the potential downstream gene of regulated by NSUN2 in gastric cancer. NSUN2 could promote gastric cancer cell proliferation through repressing p57Kip2 in an m5C-dependent manner. Our findings suggested that NSUN2 acted as an oncogene through promoting gastric cancer development by repressing p57Kip2 in an m5C-dependent manner, which may provide a novel therapeutic target against gastric cancer.
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Inhibidor p57 de las Quinasas Dependientes de la Ciclina/genética , Metiltransferasas/genética , ARN/genética , Neoplasias Gástricas/genética , Animales , Proliferación Celular , Femenino , Humanos , Metiltransferasas/efectos adversos , Ratones , Ratones Desnudos , Regulación hacia ArribaRESUMEN
The efficient transmission of severe acute respiratory syndrome-2 coronavirus (SARS-CoV-2) from patients to health care workers or family members has been a worrisome and prominent feature of the ongoing outbreak. On the basis of clinical practice and in-vitro studies, we postulated that post-exposure prophylaxis (PEP) using Arbidol is associated with decreased infection among individuals exposed to confirmed cases of COVID-19 infection. We conducted a retrospective cohort study on family members and health care workers who were exposed to patients confirmed to have SARS-CoV-2 infection by real-time RT-PCR and chest computed tomography (CT) from January 1 to January 16, 2020. The last follow-up date was Feb. 26, 2020. The emergence of fever and/or respiratory symptoms after exposure to the primary case was collected. The correlations between post-exposure prophylaxis and infection in household contacts and health care workers were respectively analyzed. A total of 66 members in 27 families and 124 health care workers had evidence of close exposure to patients with confirmed COVID-19. The Cox regression based on the data of the family members and health care workers with Arbidol or not showed that Arbidol PEP was a protective factor against the development of COVID-19 (HR 0.025, 95% CI 0.003-0.209, P=0.0006 for family members and HR 0.056, 95% CI 0.005-0.662, P=0.0221 for health care workers). Our findings suggest Arbidol could reduce the infection risk of the novel coronavirus in hospital and family settings. This treatment should be promoted for PEP use and should be the subject of further investigation.
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Antivirales/administración & dosificación , Betacoronavirus/aislamiento & purificación , Infecciones por Coronavirus/transmisión , Indoles/administración & dosificación , Transmisión de Enfermedad Infecciosa de Paciente a Profesional/prevención & control , Neumonía Viral/transmisión , Adulto , Anciano , Anciano de 80 o más Años , Antivirales/farmacología , Betacoronavirus/efectos de los fármacos , Betacoronavirus/genética , COVID-19 , Infecciones por Coronavirus/diagnóstico por imagen , Familia , Femenino , Personal de Salud , Humanos , Indoles/farmacología , Masculino , Persona de Mediana Edad , Pandemias , Neumonía Viral/diagnóstico por imagen , Profilaxis Posexposición , Análisis de Regresión , Estudios Retrospectivos , SARS-CoV-2 , Tomografía Computarizada por Rayos X , Resultado del TratamientoRESUMEN
OBJECTIVE: To investigate the injury to pulmonary tissue induced by severe acute pancreatitis (SAP) during its early period. METHODS: Forty adult male Sprague-Dawley (SD) rats weighing 300-400 g were randomly divided into 4 groups with 8 animals in each group: sham operation group and 30, 60, 120 and 360 minutes after SAP groups. The model of SAP was reproduced by retrograde injection of 5% sodium taurocholate into the pancreatic duct of rats. Rats were sacrificed at different time points, and blood gas analysis, pulmonary pathological changes and wet dry weight ratio (W/D) of the lung were conducted. RESULTS: A large amount of polymorphonuclear neutrophils were observed in pulmonary tissue within 360 minutes after reproduction of SAP with obvious changes, and water content of pulmonary tissue was increased significantly, while base excess (BE) decreased significantly in rats with SAP (P<0.05 or P<0.01 ). But no obvious change was observed in arterial partial pressure of oxygen (PaO(2)) and partial pressure of carbon dioxide (PaCO(2), both P>0.05). CONCLUSION: SAP causes significant inflammation in rat lung with injury to pulmonary tissue in its early period.
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Lesión Pulmonar/etiología , Pulmón/patología , Pancreatitis/patología , Animales , Modelos Animales de Enfermedad , Masculino , Pancreatitis/complicaciones , Distribución Aleatoria , Ratas , Ratas Sprague-DawleyRESUMEN
Podoplanin, lymphatic vessel endothelial hyaluronic acid receptor-1, prospero-related homeobox-1 and vascular endothelial growth factor receptor 3 have been demonstrated to have crucial roles in the development of the lymphatic system and lymphangiogenesis process by combining with their corresponding receptors. Thus, the four markers have been widely used in labelling lymphatic vessels for the detection of lymphangiogenesis and lymphatic vessel invasion. Numerous authors have aimed to identify the roles of these four markers in the lymphatic system and the mechanisms have been partly clarified at the molecular level. The aim of the present review was to comprehensively clarify the characteristics and latent action modes of the four markers in order to determine which is the best one for the detection of lymphangiogenesis and lymphatic vessel invasion.
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AIM: To investigate the expression of insulin-like growth factor binding protein-2 (IGFBP-2) in gastric carcinoma and its clinical significance and to explore its relationship with cell proliferation. METHODS: Expressions of IGFBP-2 and Ki-67 in 118 cases of gastric carcinoma and 40 cases of normal gastric mucosa were detected by EnVision immunohistochemical technique. RESULTS: Expression of IGFBP-2 in gastric carcinoma was higher than that in normal gastric mucosa (P < 0.01). There was no difference between high- and low-grade gastric carcinoma (P > 0.05). Expression of IGFBP-2 in advanced gastric carcinoma was higher than that in early gastric carcinoma (P < 0.05). Expression of IGFBP-2 in gastric carcinoma with lymph node metastasis was higher than that without lymph node metastasis (P < 0.01). IGFBP-2 expression was a positively related to the clinical stage of gastric carcinoma (P < 0.01). There was a positive correlation between IGFBP-2 and Ki-67 (P < 0.05). CONCLUSION: IGFBP-2 may be involved in carcino-genesis and progression of gastric carcinoma by promoting cell proliferation.
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Proliferación Celular , Proteína 2 de Unión a Factor de Crecimiento Similar a la Insulina/metabolismo , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patología , Adulto , Anciano , Progresión de la Enfermedad , Femenino , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patología , Regulación Neoplásica de la Expresión Génica , Humanos , Proteína 2 de Unión a Factor de Crecimiento Similar a la Insulina/genética , Antígeno Ki-67/genética , Antígeno Ki-67/metabolismo , Metástasis Linfática/patología , Masculino , Persona de Mediana Edad , Neoplasias Gástricas/genéticaRESUMEN
BACKGROUND: The risk of cardiovascular events remains high in patients with coronary heart disease (CHD) after successful percutaneous coronary intervention (PCI). Panax quinquefolius saponin, a major component of Xinyue capsule, has been used to treat patients with CHD. The aim of this study is to evaluate the efficacy and safety of Xinyue capsules in patients with CHD after PCI. METHODS/DESIGN: This study is a multicenter, placebo-controlled, double-blind, randomized controlled clinical trial. A total of 1100 participants are randomly allocated to two groups: the intervention group and a placebo group. The intervention group receives Xinyue capsules plus conventional treatment, and the placebo group receives placebo capsules plus conventional treatment. The patients receive either Xinyue or placebo capsules three times daily (1.8 g/day) for up to 24 weeks. The primary outcome measure is the time from randomization to the first occurrence of major adverse cardiovascular events. The secondary outcome measure is the time from randomization to the first occurrence of stroke, pulmonary embolism, and peripheral vascular events, as well as death due to any cause. All outcome measures will be assessed at 12, 24, 36, and 48 weeks after randomization. Adverse events will be monitored during the trial. DISCUSSION: The aim of this study is to evaluate the effects of Xinyue capsules on patients with CHD after interventional treatment. The results of this trial will provide critical evidence regarding Chinese herbal medicine treatment for CHD. TRIAL REGISTRATION: Chinese Clinical Trials Registry identifier ChiCTR-IPR-14005475. Registered on 10 November 2014.
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Enfermedad Coronaria/cirugía , Muerte Súbita Cardíaca/prevención & control , Medicamentos Herbarios Chinos/uso terapéutico , Infarto del Miocardio/prevención & control , Intervención Coronaria Percutánea , Saponinas/uso terapéutico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Cápsulas , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estadísticas no Paramétricas , Factores de TiempoRESUMEN
OBJECTIVE: To investigate the ability of UCB-derived MSCs to support the expansion of HSCs ex vivo and the possible mechanisms involved in this process. METHODS: HSCs from UCB were co-cultured with UCB-derived MSCs for 14 days, and then the total number of HSCs and colony-forming units (CFU) were detected. Cytokines levels of MSCs supernatant were analyzed using ELISA. RESULTS: The proliferation rate of HSCs co-cultured with MSCs was significantly higher than that of cultured HSCs alone (P<0.05). Furthermore, the addition of exogenous cytokines to the culture system significantly increased the proliferation rate of HSCs (P<0.05). MSCs had secretion of many cytokines, including GM-CSF, IL-7, IL-8, IL-11, SCF and SDF-1α. CONCLUSION: UCB-derived MSCs as a feeder layer can be an alternative approach for ex vivo expansion of HSCs, and the cytokines by secreted UCB-MSCs may mediate the supportive role of MSC to HSC proliferation.
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Proliferación Celular , Sangre Fetal , Células Madre Mesenquimatosas , Antígenos CD34 , Técnicas de Cocultivo , Citocinas , HumanosRESUMEN
AIM: To investigate the relationship between inactivation of p16 gene and gastric carcinoma, and the mechanism of inactivation of p16 gene in gastric carcinogenesis. METHODS: 40 fresh tumor tissue specimens were taken from primary gastric cancer patients. Expression of P16 protein was detected by immunohistochemical method. Deletion and point mutation of p16 gene were analyzed by polymerase chain reaction (PCR) and DNA sequencing, respectively. RESULTS: The frequency of loss of P16 protein expression in the gastric cancer tissue, adjacent nontumor tissue, and distal normal tissue was 77.5 % (31/40), 55.0 % (22/40), and 17.5 % (7/40), respectively (P<0.005). Homozygous deletion of exon 1 and exon 3 was observed in two and three cases, respectively, giving an overall frequency of homozygous deletion of 12.5 %. All five cases had diffuse type gastric carcinoma. No p16 gene point mutation was detected. CONCLUSION: These findings suggest a close correlation between inactivation of p16 gene and gastric carcinoma. Further investigations are needed to testify the mechanism of inactivation of p16 gene in gastric carcinogenesis.
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Genes p16 , Neoplasias Gástricas/genética , Adulto , Anciano , Secuencia de Bases , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , ADN de Neoplasias/genética , Exones , Femenino , Expresión Génica , Homocigoto , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Mutación Puntual , Eliminación de Secuencia , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologíaRESUMEN
OBJECTIVES: Long-term use of methamphetamine (MA) induces the neuron damage and leads to multiple neuropsychiatric disorders. However, the effect of MA on the female reproductive functions has not yet been evaluated. The objective of this study was to determine the prevalence of abnormal menstrual cycling in female MA users. METHODS: Female MA users (N = 113) were recruited from the Zhangjiang Isolated Compulsory Detoxification Center. Gynecologic history and drug use history were recorded, and serum levels of follicle-stimulating hormone, luteinizing hormone, prolactin, estrogen, progesterone, and testosterone were measured. RESULTS: Long-term use of MA significantly altered the menstrual cycle, and 33.6% women suffered from abnormal uterine bleeding while using MA. Deregulation of sex hormones was observed in 73.3% of participants during abstinence. The most common patterns were simple anovular menstruation, which was caused mainly by a hypothalamic deregulation and pituitary suppression with or without ovarian suppression. Normal hormone levels were observed more frequently in participants abstinent for more than 10 months (39.5%) than in participants who were abstinent for less than 10 months (18.6%). However, no relationship was found between hormone deregulation and age or history of MA use. CONCLUSIONS: The present data demonstrate that long-term use of MA results in the disruption of menstrual cycles and dysfunction of hypothalamic-pituitary-gonadal axis in women.
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Trastornos Relacionados con Anfetaminas/complicaciones , Estimulantes del Sistema Nervioso Central/efectos adversos , Sistema Hipotálamo-Hipofisario/efectos de los fármacos , Ciclo Menstrual/efectos de los fármacos , Metanfetamina/efectos adversos , Ovario/efectos de los fármacos , Adulto , Trastornos Relacionados con Anfetaminas/sangre , Trastornos Relacionados con Anfetaminas/fisiopatología , Estrógenos/sangre , Femenino , Hormona Folículo Estimulante/sangre , Humanos , Sistema Hipotálamo-Hipofisario/fisiopatología , Hormona Luteinizante/sangre , Trastornos de la Menstruación/sangre , Trastornos de la Menstruación/inducido químicamente , Trastornos de la Menstruación/fisiopatología , Ovario/fisiopatología , Progesterona/sangre , Prolactina/sangre , Testosterona/sangre , Adulto JovenRESUMEN
In order to obtain ammonia volatilization flux and volatilization loss rate in the vegetable field and investigate their relationship with environmental factors, an on-line monitoring system was used to measure the ammonia volatilization in the vegetable (Brassica rapa L. and lettuce) field after urea application during January to September, 2009. The system included a wind tunnel system, a gas collector and an online analyzer system with ion chromatography. The time resolution of measurement was 15 min. The recovery of the system was (92.6 +/- 3.4)%; the accumulated ammonia volatilization within 15 d continuous sampling after fertilization was regarded as the total loss. The accumulated ammonia volatilization of 12 d continuous sampling after fertilization accounted for (85.4 +/- 5.2)% of the total volatilization. The ammonia volatilization loss of broadcasting basal dressing and top dressing for Brassica rapa L. were 23.6% and 21.3%, respectively. The ammonia volatilization loss of holing basal dressing and top dressing for lettuce were 17.6% and 24.0%, respectively. The ammonia volatilization in the vegetable field mostly occurred in the first 2-3 weeks after fertilization. The ammonia volatilization flux had significant positive correlation with the nitrogen application rate, while the ammonia volatilization loss rate had negative correlation with the nitrogen application rate. The ammonia volatilization flux was positively correlated with the soil temperature (r = 0.041, p < 0.05) and the air temperature (r = 0.049, p < 0.01), while not significantly associated with the air humidity and the soil moisture. Temperature was found to be a main factor influencing the ammonia volatilization in the vegetable field.
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Contaminantes Atmosféricos/análisis , Amoníaco/análisis , Fertilizantes , Urea , Verduras/crecimiento & desarrollo , China , Monitoreo del Ambiente , VolatilizaciónRESUMEN
Along with urbanization and environmental deterioration within China, many residents' desire for improved air quality has increased. To address this topic, this study focuses on the relationship between poor air quality and residents' willingness to pay for improved air quality in the city of Ji'nan. As a means of quantifying an individual's willingness to pay (WTP) for improved air quality, a contingent valuation method (CVM) was employed. A sample of 1500 residents was chosen, based on the stratified sampling method. The respondents' WTP was then elicited through a series of face-to-face interviews, conducted using a range of hypothetical, open-ended scenario questions. The results showed that 59.7% of respondents were able to express a positive WTP, and that the average WTP was 100 Chinese Yuan (CNY) per person, per year. In order to establish the relationship between endogenous variables and WTP, both a Probit model on the probability of a positive WTP, and a stepwise regression model were constructed. Most parameters in the econometric analysis demonstrated the expected results. It was found that annual household income, expenditure on the treatment of respiratory diseases and workers in the family significantly influenced WTP. The rates of positive WTP and the monetary amount were also larger for men than for women. Unlike developed countries, most respondents regard air quality improvement as a government responsibility in that more than 40% of respondents had no incentive to bear the costs of attempting to achieve better air quality, indicating a relatively low environmental consciousness.