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1.
Ecotoxicol Environ Saf ; 222: 112462, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34217113

RESUMEN

Endocrine disrupting chemicals (EDCs) including 17ß-estradiol (E2) are widely distributed in the aquatic environment and are known to negatively affect the reproductive system of many animals, including fish. EDCs leading to feminization, altered sex ratio and reduced fecundity, it is possibly posing potential risks to the ecosystems. To investigate the potentially toxic effects of E2 exposure on little yellow croaker (Larimichthys polyactis, L. poliactis) who have a unique gonadal development pattern that males undergo a hermaphroditic stage. An experiment was set up where L. poliactis were maintained in tanks and exposed to E2 concentrations of 10 µg/L or no E2 exposure (the ethanol and control groups) from 30 to 90 days post-hatching (dph). After exposure, the E2 withdrawal and continual cultured to 150 and 365 dph. The morphological and histological analyses were used to compare the changes in the fish body and gonad under E2 exposure. The results showed that E2 exposure caused three major phenotypes at 30 and 60 days after treatment (dat), including ovary, ovotestis and gonadal development retardation compared with the control groups. The average ratio of these three phenotypes is 60.6%, 11.97% and 27.43%, respectively. The body length and weight of E2 exposure groups were repressed during the E2 exposure period, while it can recover after E2 withdrawal. However, the gonadal development (Gonadosomatic Index) of E2 exposure groups testis were retarded at 60 dat and doesn't recover until 365 dph. The sex determination/differentiation-related genes erα, erßI, erßII, fshß and cyp11b2 were significantly decreased in E2-exposure male fish. This research highlights the E2 leads to feminization, disrupts testis maturation and spermatogenesis, this effect persisted into the stage of sexual maturity. Collectively, our findings provide insights into the molecular mechanisms underlying E2 disturbance of a marine economic fish reproduction.


Asunto(s)
Estradiol , Perciformes , Animales , Ecosistema , Estrógenos , Femenino , Gónadas , Masculino
2.
Nature ; 545(7653): 213-218, 2017 05 11.
Artículo en Inglés | MEDLINE | ID: mdl-28424520

RESUMEN

Olefin chemistry, through pericyclic reactions, polymerizations, oxidations, or reductions, has an essential role in the manipulation of organic matter. Despite its importance, olefin synthesis still relies largely on chemistry introduced more than three decades ago, with metathesis being the most recent addition. Here we describe a simple method of accessing olefins with any substitution pattern or geometry from one of the most ubiquitous and variegated building blocks of chemistry: alkyl carboxylic acids. The activating principles used in amide-bond synthesis can therefore be used, with nickel- or iron-based catalysis, to extract carbon dioxide from a carboxylic acid and economically replace it with an organozinc-derived olefin on a molar scale. We prepare more than 60 olefins across a range of substrate classes, and the ability to simplify retrosynthetic analysis is exemplified with the preparation of 16 different natural products across 10 different families.


Asunto(s)
Alquenos/química , Alquenos/síntesis química , Productos Biológicos/química , Productos Biológicos/síntesis química , Ácidos Carboxílicos/química , Alquenos/clasificación , Amidas/química , Productos Biológicos/clasificación , Dióxido de Carbono/química , Dióxido de Carbono/aislamiento & purificación , Catálisis , Hierro/química , Níquel/química , Oxidación-Reducción , Policétidos/síntesis química , Policétidos/química , Especificidad por Sustrato , Tartratos/síntesis química , Tartratos/química , Zinc/química
3.
Zhongguo Gu Shang ; 29(9): 820-824, 2016 Sep 25.
Artículo en Chino | MEDLINE | ID: mdl-29282952

RESUMEN

OBJECTIVE: To compare the therapeutic effects between needle knife therapy combined with rotation traction manipulation and rotation traction manipulation for the treatment of cervical spondylotic radiculopathy. METHODS: From November 2013 to June 2015, 80 patients with cervical spondylotic radiculopathy meeting the inclusion criteria were divided into two groups randomly:the control group in which 39 patients were treated with rotation traction manipulation, and the treatment group in which 41 patients were treated with needle knife combined with rotation traction manipulation. The patients in the control group were treated once dayly for 2 weeks, which was 1 course. The patients in the treatment group were treated with needle knife firstly once a week for 2 weeks, which was 1 course;then were treated with the same methods as the patients in the control group. The symptoms, signs score and the therapeutic effects of the two groups before and after treatment were observed. RESULTS: After treatment, symptoms and signs scores declined in both groups(P<0.05). The results of the treatment group were better than effects in the control group(P<0.05). In the treatment group, 19 patients got an excellent result, 16 good, 5 fair and 1 bad;while in the control group, 10 patients got an excellent result, 10 good, 16 fair and 3 bad;the results of the treatment group were better than the results of the control group(P<0.01). CONCLUSIONS: Needle knife combined with rotation traction manipulation is an effective method for the treatment of cervical spondylotic radiculopathy, which is better than using manipulation method simply. Needle knife therapy has follow advantages:improving local blood circulation, reducing local content of pain substance, increasing production of substances resisting pain, opening channels and collaterals, and make body reaching new static and dynamic balance on the new foundation.


Asunto(s)
Manipulaciones Musculoesqueléticas/métodos , Radiculopatía/terapia , Tracción/métodos , Vértebras Cervicales , Humanos , Agujas , Ensayos Clínicos Controlados Aleatorios como Asunto , Rotación , Espondilosis/complicaciones , Resultado del Tratamiento
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