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排序方式: 共有506条查询结果,搜索用时 15 毫秒
1.
S H Faro A R Turtz R A Koenigsberg F B Mohamed C Y Chen H Stein 《AJNR. American journal of neuroradiology》1997,18(8):1588
The MR imaging features of a paraganglioma of the cauda equina with associated spinal cord cysts are presented. MR imaging showed the tumor to be isointense with the spinal cord on all pulse sequences and to enhance homogeneously. The intramedullary cysts had increased signal intensity on proton density- and T2-weighted images, and involved the cervical and thoracic regions. 相似文献
2.
吡酮酸类抗菌药物的研究Ⅷ.1-对氟苯基-6-氟-1,4-二氢-4-氧-7-(1-哌嗪)噌啉-3-羧酸及其类似物的合成和构效关系 总被引:1,自引:0,他引:1
为探讨构效关系,合成了1-对氟苯基-6-氟-1,4-二氢-4-氧-7-(1-哌嗪)噌啉-3-羧酸及其喹啉、萘啶、吡啶[2,3-C]哒嗪环系类似物16个。测定了对大肠杆菌的MIC。用Hückel分子轨道理论(HMO)方法计算了四个母体环上电子密度。结果表明:环中氮的位置对药效团——3位羧基和4位羰基氧原子上电子密度的影响较大而影响其抗菌活性。喹啉、萘啶两环系的3位羧基和4位羰基氧原子上的电子密度较高,其体外抗菌活性较高;而噌啉及吡啶[2,3-C]哒嗪两环系的电子密度较低,其体外抗菌活性较低甚至消失。 相似文献
3.
4.
C Y Chen R A Zimmerman S Faro B Parrish Z Wang L T Bilaniuk T Y Chou 《AJNR. American journal of neuroradiology》1996,17(7):1303
PURPOSETo evaluate abnormalities of the cerebral operculum in infants and children and to propose the embryogenic basis of abnormal opercular formation as determined from MR imaging findings.METHODSEighty-six infants and children who had abnormally wide interopercular distances and/or distorted opercular topography seen on MR images were studied retrospectively. Clinically, patients presented with tonal abnormalities, macrocephaly, microcephaly, seizures, developmental delay, cerebral palsy, or facial dysmorphism. The abnormal opercula were compared with developing opercula at different stages of gestation.RESULTSAmong the 86 infants and children, two categories of opercular abnormalities were identified: an underdeveloped operculum (n = 64) and a malformed operculum (n = 22). The malformed operculum was further classified into three subtypes: nonformation of the operculum with lissencephaly (n = 1, 1%), abnormal opercular formation with pachygyria (n = 11, 13%), and nonformation or abnormal formation of the operculum without pachygyria or lissencephaly (n = 10, 12%). Two subtypes of the underdeveloped operculum were identified: an open operculum without a normal insula (n = 6, 7%) and an open operculum with a normal insula (n = 58, 67%). The five subtypes of abnormal opercular configuration showed a range of maturity that was comparable to the developing operculum at different ages.CONCLUSIONOpercular anomalies appear to follow sequentially predetermined normal steps in development. Arrest in opercular development or malformation may occur after an initial insult. MR imaging is the method of choice by which to identify these abnormalities. 相似文献
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6.
Van de Velde H; De Vos A; Joris H; Nagy ZP; Van Steirteghem AC 《Human reproduction (Oxford, England)》1998,13(11):3160-3164
In human in-vitro fertilization (IVF), the oocytes are surrounded by
cumulus and corona cells at the time of insemination so that their maturity
cannot easily be evaluated. The best IVF results are obtained if the
oocytes are inseminated 2-6 h after retrieval. In the intracytoplasmic
sperm injection (ICSI) procedure, the oocytes are denuded by enzymatic and
mechanical treatment in order to be able to perform the injection. As a
consequence, the nuclear maturity of the oocytes can be evaluated and only
those that have extruded the first polar body are injected. However,
metaphase-II oocytes that have not yet reached cytoplasmic maturity cannot
be recognized. The purpose of this study was to investigate the effect of
different timing of cumulus- corona cell removal and injection on the
outcome of ICSI. For this we allowed the oocytes to complete in-vitro
cytoplasmic maturation in two different culture conditions: (i) surrounded
by their cumulus and corona cells or (ii) totally denuded. We performed
three different studies on sibling oocytes obtained after a standardized
buserelin/human menopausal gonadotrophin (HMG) protocol. We investigated
the effect of early (1-2 h after retrieval) and late (5-6 h after
retrieval) oocyte denudation and injection on the survival and
fertilization of the injected oocytes and on embryo cleavage after
fertilization. We found no statistically significant differences between
early and late injection, indicating that after a standardized
buserelin/HMG protocol the metaphase-II oocytes do not need time for
further cytoplasmic maturation. Furthermore, a different timing of
cumulus-corona cell removal has no effect on the outcome of ICSI,
suggesting that the surrounding cells are not necessary for survival,
fertilization and cleavage after ICSI.
相似文献
7.
Percoll gradient centrifugation can be omitted in sperm preparation for intracytoplasmic sperm injection 总被引:4,自引:3,他引:4
De Vos A; Nagy ZP; Van de Velde H; Joris H; Bocken G; Van Steirteghem A 《Human reproduction (Oxford, England)》1997,12(9):1980-1984
Prior to intracytoplasmic sperm injection (ICSI), seminal fluid is
currently washed out from the ejaculated semen and further sperm selection
is carried out by a discontinuous Percoll gradient. Possible deleterious
effects from the sperm-separating substance Percoll on sperm function or
embryo cleavage after in-vitro fertilization (IVF) have, to our knowledge,
not yet been reported and the use of Percoll has been widely accepted in
IVF. In this study, we examined whether the omission of the Percoll step in
the sperm preparation has any influence on the outcome of the ICSI
procedure. Two methods of sperm preparation for ICSI were compared in a
controlled study on sibling oocytes: washing the semen sample once,
followed by a Percoll gradient centrifugation versus washing the sperm
sample twice without a Percoll gradient centrifugation. The mean
fertilization rates were similar for the two sperm preparation methods:
78.2 +/- 21.4 and 75.0 +/- 24.1% respectively of the intact oocytes
displaying two pronuclei. Cleavage rates did not differ statistically
between the two groups. Whereas in both groups similar percentages of
excellent, good and poor quality embryos were obtained, the percentage of
fair quality embryos was significantly higher in the group without Percoll
(16.3 +/- 20.1 versus 9.1 +/- 15.7%). However, no statistical differences
were observed in either the percentage of transferable embryos or in the
percentage of embryos actually transferred or frozen in the two groups. In
conclusion, spermatozoa from ejaculates that are washed out from the
seminal fluid without any further selection can be used for ICSI without
any adverse effect on fertilization and embryo cleavage.
相似文献
8.
Martins LM Peltre G da Costa Faro CJ Pires EM da Cruz Inácio FF 《International archives of allergy and immunology》2005,136(1):7-15
BACKGROUND: Ingestion of snails can induce strong asthmatic or anaphylactic responses, mainly in house-dust-mite-sensitized patients. The aim of this study was to identify the Helix aspersa (Hel a), Theba pisana (The p) and Otala lactea (Ota l) allergens and the extent of their cross-reactivity with the Dermatophagoides pteronyssinus (Der p) mite. PATIENTS AND METHODS: In 60 atopic patients, skin prick tests (SPT) to snail and D. pteronyssinus, total and specific IgE, specific IgE immunoblots, RAST and immunoblot inhibition assays were performed. RESULTS: Mean total IgE was >1,000 kU/l. Mean specific IgE (class 6 for Der p and class 2 for Hel a) SPT were positive in 44 patients for snail and in 56 for mite. Isoelectric focusing (IEF) and SDS-PAGE followed by immunoblotting of H. aspersa extract enabled the identification of 27 and 20 allergens, respectively. Myosin heavy chains from snails (molecular weight >208 kDa) disclosed two major allergens. Hel a and Der p RAST were strongly inhibited by their homologous extracts, with Hel a RAST being inhibited by the Der p extract to a much greater extent (72.6%) than the inverse (5.6%). A complete inhibition of the immunoblots by their homologous extract was obtained. However, Hel a extract did not inhibit Der p IEF separated recognition. On the other hand, mite extract extensively inhibited snail immunoblots from both IEF and SDS-PAGE separations. Immune detection on chicken, pig, rabbit, cow and horse myosins did not reveal any IgE cross recognition with snail. CONCLUSIONS: In most cases of snail allergy, mite appeared to be the sensitizing agent. Nevertheless, snails may also be able to induce sensitization by themselves. This hypothesis is supported by the finding of specific IgE to Hel a in 2 patients who did not show specific IgE to Der p, and one of them was suffering from asthma after snail ingestion. 相似文献
9.
Maffei HV Moreira FL Kissimoto M Chaves SM Faro SE Aleixo AM 《Jornal de pediatria》1994,70(5):280-286
In order to better understand the natural history of chronic functional constipation, a questionnaire was applied to 163 children and infants, before beginning standardized treatment. Median age (range) at start was 3 mo(0-108 mo) but age at arrival at the Pediatric Gastroenterology Unit was 53 mo(2-146 mo). In 62.4% of the cases symptoms began before or up to 3 mo after cow's milk introduction and rarely around (-/+ 6 mo) toilet training. Possible complications appeared progressively, often at preschool or school age or as the first noticeable manifestation: recurrent abdominal pain (61.1%), fecal soiling (45.4%), fecal blood (35%), enuresis (23.3%), vomiting (19%), urinary infection (17.9%), urinary retention (8.6%). Abdominal distension was rarely detected on physical examination and was usually discrete. In conclusion, children attended in Botucatu begin their constipation at an early age, frequently associated with weaning,and important complications may ensue along years. This evolution should be avoided by prevention and early treatment of constipation. 相似文献
10.