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61.
62.
The bias favoring deletion over inversion in DH-JH rearrangement has been
known for years, but the underlying mechanism has yet to be fully defined.
It has been suggested that the ratio of deletion/inversion is determined by
the combined effect of two factors: (i) the relative strengths of 5' and 3'
recombination signal sequences (RSS) of a DH segment, and (ii) the
efficiency with which the deletional product (one joint) forms relative to
the inversional product (two joints). In this study, we analyzed for the
first time the effect of factor 1 alone on the biased 3' RSS utilization in
DH-JH joining by using deletional plasmids in an extrachromosomal substrate
V(D)J recombination assay. It was found that the 3' RSS and associated
coding end (12 bp) mediate recombination more efficiently than the 5'
RSS/coding end DH-JH plasmids. These results demonstrate that the effect of
the RSS/coding end alone can account, at least partially, for the
predominant deletion in DH-JH recombination. The potential effect of the
relative strength of RSS and associated coding end on the ordered
rearrangement of DH-JH followed by VH to DH-JH was also assessed. When
recombination frequencies of D-->J (3' DH to J3) were compared with
frequencies of V-- >D (VHPJ14 to 3' DH or VHOX2 to 3' DH), it was found
that V-->D joining was, if anything, more efficient than D-->J
joining. Therefore, if all three segments were accessible, RSS/coding end
effects would not contribute to the ordered rearrangement of the IgH locus.
相似文献
63.
Okazaki K Takada A Ito T Imai M Takakuwa H Hatta M Ozaki H Tanizaki T Nagano T Ninomiya A Demenev VA Tyaptirganov MM Karatayeva TD Yamnikova SS Lvov DK Kida H 《Archives of virology》2000,145(5):885-893
Summary. Influenza A viruses of different subtypes were isolated from fecal samples of ducks in their nesting areas in Siberia in
summer from 1996 to 1998. Phylogenetic analysis of the NP genes of the isolates in Siberia and those in Hokkaido, Japan on
their flyway of migration from Siberia to the south in autumn revealed that they belong to the Eurasian lineage of avian influenza
viruses. It is noted that the genes of the isolates in Siberia are closely related to those of H5N1 influenza virus strains
isolated from chickens and humans in Hong Kong in 1997 as well as to those of isolates from domestic birds in southern China.
The results indicate that influenza viruses perpetuated in ducks nesting in Siberia should have contributed genes in the emergence
of the H5N1 virusin Hong Kong. Vaccine prepared from avirulent A/duck/Hokkaido/4/96 (H5N3) influenza virus was potent enough
to protect mice from challenge with lethal dose of the pathogenic H5N1 virus [19]. Intensive surveillance study of aquatic
birds especially in Siberia is, therefore, stressed to provide information on the future pandemic influenza virus strains
and for vaccine preparation.
Received August 24, 1999/Accepted January 7, 2000 相似文献
64.
Differences in the uptake of tracers from radioactive 2-deoxyglucose ([1,2-3H] and [2,6-3H]), and glucose ([1-3H], [3-3H]) into hippocampal regions were investigated by freeze-mount microautoradiography after 45 min for 2-deoxyglucose, and after 15 and 45 min for glucose. Silver grains were assessed quantitatively by an image analyser. (1) The radioactivity (silver grains/mm2) in the stratum lacunosum-moleculare of Ammon's horn from 2-deoxyglucose autoradiograms was significantly higher than that in other hippocampal regions (P less than 0.01), while lowest in the hilus fascia dentata (P less than 0.01). (2) Autoradiograms of [1-3H]glucose and 15 min of [3-3H]glucose showed the radioactivity in the dentate molecular layer to be significantly higher than that in other regions, excepting the stratum lacunosummoleculare (P less than 0.05). (3) The 2-deoxyglucose and 45-min glucose autoradiograms showed intensely labeled perikarya of pyramidal cells in the CA3a sector. (4) Radioactivity in the dentate granular layer from the 45-min autoradiogram of [3-3H]glucose was significantly higher than that in the molecular layer (P less than 0.05). The results imply that the metabolic fate of glucose, i.e. whether it is mainly used for energy production or amino acid synthesis, depends on each structure of the hippocampus. 相似文献
65.
66.
H Adachi T Yumoto I Takeda M Ozaki N Matsumoto T Ishihara F Uchino 《Acta pathologica japonica》1989,39(4):254-259
A study was conducted on two brothers with Jordans' anomaly. Fat-containing vacuoles were noticed in all leukocytes of the peripheral blood and cells of the myeloid series including myeloblasts, but the serum lipids showed no abnormalities. However, cells of the erythroid series, megakaryocytes and platelets did not contain these vacuoles. An increase in vacuole number was observed as the leukocytes matured. Histochemically, it was suggested that these vacuoles contained neutral fat based on staining with Sudan III and Nile blue sulfate. Ultrastructurally, these vacuoles were unassociated with lysosomes or other cell organelles. Although the etiology of Jordans' anomaly could not be clarified by this study, genetic factors may be involved. 相似文献
67.
MR Sanguina R Perotta F Brunelli A Gilbert JP Lassau 《Surgical and radiologic anatomy : SRA》1994,16(1):111-112
Summary A cortico-cancellous flap from the anterolateral aspect of the upper third of the tibia was presented. Sixty lower limbs of fresh cadavers were dissected. The vascular bundle includes the anterior tibial artery and its recurrent collateral branches and recurrent and muscllo periostal arteries. The flap is harvested with the interosseous membrane and can be used either free or pedicled. We used this flap for two patients suffering from pseudarthrosis. Long range clinical and radiological results are good.
Le transfert osseux vascularisé tibial superieur
Résumé Les auteurs décrivent un transfert ostéo-periosté vascularisé, prélevé sur la face antéro-latérale de l'extremité supérieure du tibia. L'étude anatomique porte sur soixante membres inférieurs, conservés au froid. La vascularisation métaphysaire du transfert provient de la branche récurrente tibiale antérieure et de ses rameaux, la vascularisation diaphysaire étant issue des branches musculo-périostiées proximales. Le transfert vascularisé est prélevé avec la membrane interosseuse et peut être pediculé ou libre. L'expérience clinique porte sur deux cas de pseudarthroses multiopérées. Les résultats cliniques et radiologiques sont bons à long terme.相似文献
68.
Fifty women with polycystic ovaries took part in a prospective randomized
study. All women required treatment by in-vitro fertilization (IVF) for
reasons other than anovulation. They had all previously undergone ovarian
stimulation with gonadotrophin therapy which had failed to result in
pregnancy or had been abandoned due to high risk of developing ovarian
hyperstimulation syndrome (OHSS). Twenty-five women were treated by
long-term pituitary desensitization followed by gonadotrophin therapy,
oocyte retrieval and embryo transfer (group 1). Twenty-five women underwent
laparoscopic ovarian electrocautery after pituitary desensitization
followed by gonadotrophin therapy, oocyte retrieval and embryo transfer
(group 2). A significantly higher number of women in group 1 had to have
the treatment cycle abandoned due to impending or actual OHSS, determined
by endocrine and clinical findings. In addition, the development of
moderate or severe OHSS in completed cycles was higher in group 1. The
pregnancy rate and miscarriage rates in the two treatment groups were
similar. The authors propose that laparoscopic ovarian electrocautery is a
potentially useful treatment for women who have previously had an IVF
treatment cycle cancelled due to risk of OHSS or who have suffered OHSS in
a previous treatment cycle.
相似文献
69.
70.
DL?MagerEmail author AD?Haffajee PM?Devlin CM?Norris MR?Posner JM?Goodson 《Journal of translational medicine》2005,3(1):27