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排序方式: 共有299条查询结果,搜索用时 31 毫秒
21.
dos Santos Miron D Crestani M Rosa Shettinger M Maria Morsch V Baldisserotto B Angel Tierno M Moraes G Vieira VL 《Ecotoxicology and environmental safety》2005,61(3):597-403
Fingerlings of the silver catfish (Rhamdia quelen) were exposed to three herbicides widely used in rice culture in south Brazil: clomazone, quinclorac, and metsulfuron methyl. LC50 was determined and acetylcholinesterase (AChE) activity was evaluated in brain and muscle tissue of fish exposed to different herbicide concentrations after 96h (short term). The LC50 value (nominal concentration) was 7.32 mg/L for clomazone and 395 mg/L for quinclorac, but was not obtained for metsulfuron-methyl since all fingerlings survived the highest concentration of 1200 mg/L. Brain and muscle AChE activity in unexposed fish were 17.9 and 9.08 micromol/min/g protein, respectively. Clomazone significantly inhibited AChE activity in both tissues, achieving maximal inhibition of about 83% in brain and 89% in muscle tissue. In contrast, quinclorac and metsulfuron methyl caused increases in enzyme activity in the brain (98 and 179%, respectively) and inhibitions in muscle tissue (88 and 56%, respectively). This study demonstrated short-term effects of exposure to environmentally relevant concentrations of rice field herbicides on AChE activity in brain and muscle tissue of silver catfish. 相似文献
22.
Computed tomographic appearance of the bulging annulus 总被引:6,自引:0,他引:6
23.
Differential CT diagnosis of extruded nucleus pulposus 总被引:1,自引:0,他引:1
24.
25.
Pineal germinoma: MR imaging 总被引:6,自引:0,他引:6
Magnetic resonance (MR) imaging characteristics of pineal germinomas are described in seven patients imaged with MR and computed tomography (CT). In patients with symptoms of an enlarging process in the quadrigeminal plate cistern, MR imaging was as sensitive as CT scanning in detecting the mass. MR imaging did not detect a normal-sized, calcified neoplastic gland. Germinoma, germinoma with embryonal cell carcinoma elements, and pineoblastoma demonstrated different MR signal characteristics. Although direct coronal and sagittal MR images were useful in defining the relationship of the tumor to the posterior third ventricle, Sylvian aqueduct, and vein of Galen, the ease, rapidity, and sensitivity of CT scanning suggest that CT should remain the modality of choice for initial evaluation and screening of the pineal region, especially in the younger pediatric population, in whom detection of calcification may provide the only clue of an abnormality. 相似文献
26.
Objective. This study documents and traces the evolution of triple rhythm (Waltz) linking the great veins, corresponding systemic or
pulmonary venous sinuses and pectinated right or left atrium in frog, turtle, snake and human hearts. Alternating rhythm (duet)
between systemic and pulmonary veins has also been documented in these hearts.
Material Studied. The hearts of six dead hammer-head sharks were examined with the naked eye. Air-breathing, fresh-water fish (three Channa
striata and three Indian catfish) were anaesthetised with ketamine and their pharynx insufflated with oxygen. Six frogs, three
turtles, and two snakes were anaesthetised, intubated and ventilated. Contractions of the exposed hearts of these animals
were correlated with their electrocardiograms using superimposed videos. The human heart was observed carefully during surgery
through median sternotomy or anterolateral thoracotomy by visual inspection especially during instillation of or recovery
from cardioplegia. Digital videos were taken and studied in slow motion replay later.
Observations. In the air-breathing fish, Channa striata and Indian catfish and presumably the shark, the cardinal veins and thin walled
sinus venosus do not contract. In the frog, turtle, and snake there is sequential contraction of the systemic veins, systemic
venous sinus and pectinated right atrium. Likewise, there is waltz on the arterial side. There is a duet between systemic
and pulmonary veins, contractions of the former preceding the latter in the frog, turtle and snake. The observations are similar
in the human heart except that the inferior vena cava does not contract.
Conclusions. There is sequential contraction of the superior vena cava, the systemic venous sinus and the pectinated part of the right
atrium in the human heart. Likewise, there is a waltz linking the terminal pulmonary veins, pulmonary venous sinus and pectinated
part of the left atrium in the human heart. This waltz or triple rhythm, as well as a duet between the systemic and pulmonary
veins are seen in frog, turtle and snake. The duet is also observable in the human heart, during recovery from cardioplegia.
It is likely that the waltz and duet are conducted by a neurogenic mechanism.
Clinical Implications. The understanding, preservation and restoration of the mechanism sustaining supraventricular waltz and duet is relevant
to surgical and interventional procedures for control of atrial arrhythmia, Fontan circulation, technique for cardiac transplantation
and planning atriotomies. 相似文献
27.
Daniels DL; Czervionke LF; Millen SJ; Haberkamp TJ; Meyer GA; Hendrix LE; Mark LP; Williams AL; Haughton VM 《Radiology》1989,171(3):807-809
The authors evaluated magnetic resonance (MR) images obtained with intravenously administered gadolinium in ten patients who had facial paralysis and no facial nerve tumor. In patients with either Bell palsy (four patients) or facial paralysis after temporal bone surgery (six patients), intratemporal facial nerve enhancement was seen. Facial nerve enhancement on MR images proved to be a nonspecific finding. 相似文献
28.
John A. Kessler Aziz Shaibani Christine N. Sang Mark Christiansen David Kudrow Aaron Vinik Nari Shin the VM study group 《CTS Clinical and Translational Science》2021,14(3):1176
AbstractVM202 is a plasmid DNA encoding two isoforms of hepatocyte growth factor (HGF). A previous phase II study in subjects with painful diabetic peripheral neuropathy (DPN) showed significant reductions in pain. A phase III study was conducted to evaluate the safety and efficacy of VM202 in DPN. The trial was conducted in two parts, one for 9 months (DPN 3‐1) with 500 subjects (VM202: 336 subjects; and placebo: 164) and a preplanned subset of 101 subjects (VM202: 65 subjects; and placebo: 36) with a noninterventional extension to 12 months (DPN 3‐1b). VM202 or placebo was administered to calf muscles on days 0 and 14, and on days 90 and 104. The primary end point in DPN 3‐1 was change from baseline in the mean 24‐h Numerical Rating Scale (NRS) pain score. In DPN 3‐1b, the primary end point was safety, whereas the secondary efficacy end point was change in the mean pain score. VM202 was well‐tolerated in both studies without significant adverse events. VM202 failed to meet its efficacy end points in DPN 3‐1. In DPN 3‐1b, however, VM202 showed significant and clinically meaningful pain reduction versus placebo. Pain reduction in DPN 3‐1b was even greater in subjects not receiving gabapentin or pregabalin, confirming an observation noted in the phase II study. In DPN 3‐1b, symptomatic relief was maintained for 8 months after the last injection suggesting that VM202 treatment might change disease progression. Despite the perplexing discrepancy between the two studies, the safety and long‐lasting pain‐relieving effects of VM202 observed in DPN 3‐1b warrant another rigorous phase III study. Study Highlights
- WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?
- WHAT QUESTION DID THIS STUDY ADDRESS?
- WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?
- HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?
29.
30.
Martin Darvas Marco Morsch Ildiko Racz Seifollah Ahmadi Dieter Swandulla Andreas Zimmer 《European neuropsychopharmacology》2009,19(9):670-681
The agonist binding sensitivity and desensitization kinetics of nicotinic acetylcholine receptors (nAChRs) can be modulated by snake venom neurotoxins and related endogenous small proteins of the uPAR-Ly6 family. Here we identify Lypd6, a distantly related member of the u-PAR/Ly-6 family expressed in neurons as a novel modulator of nAChRs. Lypd6 overexpressed in trigeminal ganglia neurons selectively enhanced the Ca2+-component of nicotine-evoked currents through nAChRs, as evidenced by comparative whole-cell patch clamp recordings and Ca2+-imaging in wildtype and transgenic mice overexpressing Lypd6. In contrast, a knockdown of Lypd6 expression using siRNAs selectively reduced nicotine-evoked Ca2+-currents. Pharmacological experiments revealed that the nAChRs involved in this process are heteromers. Transgenic mice displayed behaviors that were indicative of an enhanced cholinergic tone, such as a higher locomotor arousal, increased prepulse-inhibition and hypoalgesia. These mice overexpressing Lypd6 mice were also more sensitive to the analgesic effects of nicotine. Transgenic mice expressing siRNAs directed against Lypd6 were unable to procreate, thus indicating a vital role for this protein. Taken together, Lypd6 seems to constitute a novel modulator of nAChRs that affects receptor function by selectively increasing Ca2+-influx through this ion channels. 相似文献