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按Bishop方法,在小鼠血液里诱导生成大量网织红细胞,然后提取网织红细胞。用激光衍射法测得小变形指数(DI)d和变形恢复过程(即松驰过程)中细胞变形恢复到最大值(DI)max半的时间t0.5(变形恢复半时间),将测得结果分别代入细胞膜的膜剪切弹性模量(E)公式和表面粘度(μm)公式,计算出网织红细胞和成熟红细胞膜的膜剪切弹性模量(E)和表面粘度(μm),并用荧光偏振法测量它们的膜流动性。发现网织红细胞与成熟红细胞的膜的剪切弹性模量(E)和表面粘度(μm)及膜的流动性有着明显的不同。这对研究由于贫血等原因造成的网织红细胞增多情况下,全血的微观流变特性有着重要的临床意义,对我们认识哺乳类网织红细胞的微观流变特性有重要理论意义及认识哺乳类动物网织红细胞向成熟红细胞转变的微观流变特性变化有着重要理论意义。 相似文献
774.
Cryopreservation of single human spermatozoa 总被引:6,自引:5,他引:6
Cohen J; Garrisi GJ; Congedo-Ferrara TA; Kieck KA; Schimmel TW; Scott RT 《Human reproduction (Oxford, England)》1997,12(5):994-1001
A procedure is described that allows cryopreservation and efficient
post-thaw recovery of either a single or a small group of human
spermatozoa. This is achieved by injecting them into cell-free human, mouse
or hamster zonae pellucidae before the addition of cryoprotectant. The
method involves a combination of physical micromanipulation procedures and
glycerol-mediated cryoprotection. Zonae were tracked by positioning them in
straws between two small air bubbles prior to freezing. Spermatozoa from
poor specimens were cryopreserved and their fertilizing ability after
thawing was compared with that of fresh spermatozoa from fertile men. Human
eggs used for fertilization testing were either 1 day old or in-vitro
matured. Only 2% of the frozen zonae were lost and >75% of spermatozoa
cryopreserved in this manner were recovered and prepared for
intracytoplasmic sperm injection. The feasibility of cryopreserving a
single spermatozoon was assessed. Fifteen motile spermatozoa were frozen in
15 zonae, of which 14 were recovered after thawing. Ten were injected into
spare eggs, of which eight became fertilized. Spermatozoa recovered
mechanically from human zonae fertilized the same proportion of oocytes as
fresh fertile control spermatozoa. The recovery and fertilization rates
with spermatozoa frozen in animal zonae were 87 and 78% respectively. The
fertilization rate was marginally higher (P < 0.05) than that for
spermatozoa frozen in human zonae, perhaps because the latter may have
acrosome reacted more frequently. The zona pellucida appears to be an
ideally suited sterile vehicle for storage of single spermatozoa.
相似文献
775.
Persistence of functionally compromised anti-double-stranded DNA B cells in the periphery of non-autoimmune mice 总被引:2,自引:0,他引:2
Both anti-single-stranded (ss) and anti-double-stranded (ds) DNA antibodies
are associated with the autoimmune disease systemic lupus erythematosus
(SLE), but only anti-dsDNA antibodies are considered one of the diagnostic
criteria. Using Ig transgenes coding for anti-DNA we have determined the
fate of anti-dsDNA B cells in a non-autoimmune environment. In a Rag-2
wild-type background, B cells expressing the anti-dsDNA Ig transgenes are
present in the spleen but dsDNA specificity is disrupted due to expression
of endogenous L chains. In a Rag-2-deficient background where co-expression
of endogenous Ig is blocked, splenic B cells expressing only the anti-dsDNA
transgene Ig are present, indicating that endogenous Ig expression is not
required for bone marrow export. The anti-dsDNA B cells that persist are
profoundly crippled in that they are unable to proliferate to
lipopolysaccharide or anti-Ig stimulation. Furthermore, these anti- dsDNA
Ig transgene B cells show a decreased lifespan relative to non- transgene
BALB/c B cells. Persistence of anti-dsDNA B cells in the periphery of
non-autoimmune mice raises the possibility that their appearance in the
context of SLE is due to their reactivation by T cell help.
相似文献
776.
Elisseeff J McIntosh W Anseth K Riley S Ragan P Langer R 《Journal of biomedical materials research》2000,51(2):164-171
A photopolymerizing hydrogel system provides an efficient method to encapsulate cells. The present work describes the in vitro analysis of bovine and ovine chondrocytes encapsulated in a poly(ethylene oxide)-dimethacrylate and poly(ethylene glycol) semi-interpenetrating network using a photopolymerization process. One day after encapsulation, (3-[4,5-dimethylthiazol-2-y1]-2, 5-diphenyl-2H-tetrazolium bromide) (MTT) and light microscopy showed chondrocyte survival and a dispersed cell population composed of ovoid and elongated cells. Biochemical analysis demonstrated proteoglycan and collagen contents that increased over 2 weeks of static incubation. Cell content of the gels initially decreased and stabilized. Biomechanical analysis demonstrated the presence of a functional extracellular matrix with equilibrium moduli, dynamic stiffness, and streaming potentials that increased with time. These findings suggest the feasibility of photoencapsulation for tissue engineering and drug delivery purposes. 相似文献
777.
778.
PD Correa S Arya SG Laskar SK Shrivastava KA Dinshaw T Gupta JP Agarwal 《Journal of Medical Imaging and Radiation Oncology》2005,49(2):113-118
Limited information is available about the sonomorphological changes in metastatic neck nodes during radiotherapy. The aim of this study was to evaluate the pattern of sonomorphological changes in metastatic neck nodes with radiotherapy. The study population consisted of 16 consecutive patients planned for radical radiotherapy to the head and neck. All patients were subjected to four ultrasound examinations: before therapy, at 46 Gy, at the conclusion of radiation and at first follow up. A total of 59 ultrasound examinations were performed on 16 patients. The difference between the mean number of nodes detected per patient before (10.6) and after (7.8) radiation was significant (P = 0.05). Sixteen nodes were categorized as malignant at first sonography, half of which reverted back to normal by the end of radiation. Changes in the sonomorphology of malignant cervical lymph nodes occur with radiotherapy with more that half demonstrating reversion to normal pattern. Future studies correlating this with histopathology should be considered. 相似文献
779.
780.
Previous studies of fluorodeoxyglucose positron emission tomography (FDG‐PET) in pancreatic cancer have used Bismuth Germinate detector systems. This preliminary Australian study aims to confirm the accuracy of FDG‐PET in pancreatic cancer using a dedicated sodium iodide (NaI) PET system. Fifteen consecutive patients underwent FDG‐PET using a GE QUEST dedicated NaI PET scanner. The indications were the characterization of a pancreatic mass seen on CT or ultrasonographic imaging (nine cases), diagnosis or exclusion of recurrent disease following surgery and adjuvant therapy (four cases) and presurgical staging of primary pancreatic cancer (two cases). The final diagnosis was determined from histology or, when no histology was available, by radiological and clinical follow up. The FDG‐PET accurately characterized eight out of nine pancreatic masses (seven were true negative, one was true positive and one was false positive). Of the four cases performed to determine recurrent disease, three were accurately diagnosed (two true negatives and one true positive). In the fourth case, PET accurately detected a liver metastasis but did not detect the local recurrence. Results in the two cases where PET was performed for preoperative staging comprised one true positive and one false negative. Sodium iodide FDG‐PET is useful in the diagnosis of pancreatic cancer, particularly in the presence of a previously detected mass. 相似文献