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The advantages of the new, safer, but more expensive iodinated contrast agents are discussed, and opinions on which patient groups should receive the agents are presented. 相似文献
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A modified technique for catheterization of the pulmonary artery was developed. It involves the passage of a tapered, movable-core, J-tipped guide wire across the right ventricle into the pulmonary artery followed by the advancement of a straightened Grollman pigtail catheter. The technique was successful in 34 of 34 pulmonary artery catheterizations. The method avoids prolonged catheter manipulation within the right ventricle. In addition, since the catheter does not cross the tricuspid valve until the guide wire has been advanced, the occasional complication of the pigtail "hooking" on a tricuspid valve leaflet or chordae tendineae during catheter withdrawal and manipulation is prevented. 相似文献
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乳腺管状小叶癌(Tubulolobular carcinoma,TLC)最初是被作为小叶癌的管状变型。作者总结了27例TLC的组织学、免疫表型和临床特征,并与纯小管癌和经典型小叶癌进行了比较。此组患者年龄43-79岁(中位年龄60岁)。1例双侧乳腺受累,5例病变为多灶性。肿瘤直径0.5-2.5cm,色灰褐,质硬。组织学观察:TLC的肿瘤细胞形成管状和条索状两种结构模式并相互混杂,且两者比例相当(统称为管状小叶模式)。 相似文献
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Mahadevaiah SK; Odorisio T; Elliott DJ; Rattigan A; Szot M; Laval SH; Washburn LL; McCarrey JR; Cattanach BM; Lovell-Badge R; Burgoyne PS 《Human molecular genetics》1998,7(4):715-727
An RNA-binding motif (RBM) gene family has been identified on the human Y
chromosome that maps to the same deletion interval as the 'azoospermia
factor' (AZF). We have identified the homologous gene family (Rbm) on the
mouse Y with a view to investigating the proposal that this gene family
plays a role in spermatogenesis. At least 25 and probably >50 copies of
Rbm are present on the mouse Y chromosome short arm located between Sry and
the centromere. As in the human, a role in spermatogenesis is indicated by
a germ cell-specific pattern of expression in the testis, but there are
distinct differences in the pattern of expression between the two species.
Mice carrying the deletion Yd1, that maps to the proximal Y short arm, are
female due to a position effect resulting in non-expression of Sry ;
sex-reversing such mice with an Sry transgene produces males with a high
incidence of abnormal sperm, making this the third deletion interval on the
mouse Y that affects some aspect of spermatogenesis. Most of the copies of
Rbm map to this deletion interval, and the Yd1males have markedly reduced
Rbm expression, suggesting that RBM deficiency may be responsible for, or
contribute to, the abnormal sperm development. In man, deletion of the
functional copies of RBM is associated with meiotic arrest rather than
sperm anomalies; however, the different effects of deletion are consistent
with the differences in expression between the two species.
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The alpha2-adrenoreceptor (AR) is the most investigated noradrenergic receptor with regard to modulation of seizure activity. However, because of the complexity of multiple alpha2-AR subtypes and their distribution, the exact role of this receptor in modulating seizure activity is not clear. alpha2A- and alpha2C-ARs function as both autoreceptors (presynaptic) on noradrenergic neurons, where they regulate norepinephrine (NE) release, and as postsynaptic receptors on neurons that receive noradrenergic innervation, where they regulate the release of other neurotransmitters (heteroreceptor). The nonselective alpha2-AR agonist clonidine produced a proconvulsant effect on seizure susceptibility, while the selective alpha2A-AR agonist guanfacine was anticonvulsant. The effects of both alpha2-AR agonists were absent in alpha2a knockout mice, suggesting that the alpha2A-AR mediates the proconvulsant and anticonvulsant effect of alpha2-AR agonists on seizure susceptibility. To determine whether the alpha2-AR agonists were acting on inhibitory presynaptic autoreceptors to decrease NE release or on postsynaptic receptors on NE target neurons, the effects of clonidine and guanfacine were determined in dopamine beta-hydroxylase knockout (Dbh -/-) mice that lack NE. The anticonvulsant effect of guanfacine persisted in Dbh -/- mice, suggesting that guanfacine may act preferentially on alpha2A-postsynaptic receptors that regulate the action of NE on target neurons. In contrast, the proconvulsant effect of clonidine was lost in Dbh -/- mice, suggesting that clonidine may act on presynaptic autoreceptors to decrease NE release. We hypothesize that the alpha2A-presynaptic autoreceptor is responsible for the proconvulsant effect of alpha2-AR agonists, while the alpha2A-postsynaptic receptor is responsible for the anticonvulsant effect of alpha2-AR agonists. These data help to clarify the inconsistent effects of alpha2-AR agonists on seizure activity. 相似文献