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1.
2.
The beta-amyloid (Abeta) precursor protein (APP) is cleaved sequentially by beta-site of APP-cleaving enzyme (BACE) and gamma-secretase to release the Abeta peptides that accumulate in plaques in Alzheimer's disease (AD). GGA1, a member of the Golgi-localized gamma-ear-containing ARF-binding (GGA) protein family, interacts with BACE and influences its subcellular distribution. We now report that overexpression of GGA1 in cells increased the APP C-terminal fragment resulting from beta-cleavage but surprisingly reduced Abeta. GGA1 confined APP to the Golgi, in which fluorescence resonance energy transfer analyses suggest that the proteins come into close proximity. GGA1 blunted only APP but not notch intracellular domain release. These results suggest that GGA1 prevented APP beta-cleavage products from becoming substrates for gamma-secretase. Direct binding of GGA1 to BACE was not required for these effects, but the integrity of the GAT (GGA1 and TOM) domain of GGA1 was. GGA1 may act as a specific spatial switch influencing APP trafficking and processing, so that APP-GGA1 interactions may have pathophysiological relevance in AD.  相似文献   
3.
应用放射配体结合法证实大鼠胸腺内存在降黑素特异结合部位,该结合位点可以满足特异结合部位的基本条件:1.低结合容量;2.高亲和力;3.可饱和性;4.可逆性;5.对降黑素高度特异性。此外,该特异结合位点具昼夜节律;亚细胞分布的研究表明以细胞核含量最高,线粒体次之,并具有年龄依赖性降低,以出生时最高。  相似文献   
4.
We report a rare case of early-stage endometrial adenocarcinoma in a 22 year old nullipara with polycystic ovaries undergoing conservative treatment. Pretreatment evaluation including tumour grade, depth of myometrial invasion, tumour size, hormone receptor status and flow cytometric analysis indicated a favourable prognosis. The patient underwent repeat endometrial curettage and a 6 month period of therapy with megestrol acetate and tamoxifen. A combination contraceptive pill was then prescribed to ensure withdrawal of the menstrual cycle thereafter. Now, 1 year after the last curettage, there is no evidence of disease. During the treatment period, hysteroscopy allowed for a more precise approach in panoramically examining the tumour nest in the endometrial cavity, and the subsequent endometrial response to hormone therapy. Laparoscopy using bulldog clamps applied to the isthmic portion of the Fallopian tubes prevented i.p. spread of endometrial tissue from retrograde regurgitation during hysteroscopy. Laparoscopic ovarian electrocautery resulted in the reduction of abnormal hypervascularization on the surface of polycystic ovaries postoperatively but caused a peri-ovarian adhesion complication. It is interesting that this case posed a unique opportunity to demonstrate the tumour regression under the assistance of laparoscopy and hysteroscopy.   相似文献   
5.
1. The effects of light flashes or sound clicks on somatic sensory activity in the cuneate nucleus of the cat were studied. Polysensory interactions were demonstrated by means of gross potential recording in the cuneate nucleus or medial lemniscus, single unit recording in the cuneate nucleus, and excitability testing of tract terminals.

2. Brief flashes or clicks were found to produce negative (N) and positive (P) waves in the cuneate nucleus similar to those produced by cutaneous stimulation. Furthermore, the P wave evoked by conditioning photic or acoustic stimuli depressed the P wave produced by cutaneous test stimuli.

3. Conditioning photic or acoustic stimuli inhibited spontaneously firing cuneate neurones as well as those driven by cutaneous test stimuli.

4. Conditioning photic or acoustic stimuli depressed the test discharge in the medial lemniscus evoked by cutaneous test stimuli.

5. Micro-electrode stimulation within the cuneate nucleus evoked an antidromic response in the superficial radial nerve consisting of two spike complexes. Conditioning photic or acoustic stimuli caused an increase in the size of the initial spike complex and a depression in the secondary spike complex. These changes and the time courses of all the interactions observed were suggestive of presynaptic inhibition.

6. The modulatory influences of photic and acoustic stimuli on the cuneate nucleus were present under α-chloralose or pentobarbitone anaesthesia and the acoustic influence persisted after midcollicular decerebration. When added to other evidence, the above findings suggest that the reticular formation of the brain stem plays an important role in these polysensory interactions.

  相似文献   
6.
BACKGROUND: Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are known to occur in patients after major abdominal surgery. The incidence of IAH and ACS in the burn population is not known. METHODS: We prospectively recorded the intra-abdominal pressures of major burn patients admitted to our burn center from February 1999 to September 1999. A bladder pressure greater than 25 mm Hg was diagnosed as IAH. ACS was diagnosed when pulmonary compliance decreased in association with persistent IAH and was treated with abdominal decompression. RESULTS: Ten patients were placed on the protocol; of these, seven developed IAH. Five responded to conservative treatment. Two patients with 80% body surface area burns developed ACS and required decompression. CONCLUSIONS: IAH occurs commonly in major burn patients, and ACS is seen regularly in patients with more than 70% body surface area burns. We recommend bladder pressure measurements after infusion of more than 0.25 L/kg during the acute resuscitation phase and for peak inspiratory pressures greater than 40 cm H2O. Whereas ACS warrants surgical decompression of the abdominal cavity, IAH usually responds to conservative therapy.  相似文献   
7.
Pierre Robin sequence (PRS) describes a small mandible with retrognathia, an elevated and posteriorly positioned tongue, and an associated U-shaped cleft palate. The retracted tongue may obstruct the airway leading to respiratory failure, with failure to thrive and adverse neurodevelopmental outcomes if not addressed. If the airway obstruction cannot be overcome with conservative measures, there are non-surgical and surgical options. A nasopharyngeal prong (NPP) is a non-surgical, temporary treatment that avoids the complications inherent in an operation, especially given the natural history of mandibular growth and improved airway obstruction in PRS. Although the use of a prong requires training, support, and follow up, it effectively bypasses the obstruction in the majority of children with PRS, and allows the child to outgrow the airway obstruction until the prong is no longer required. On average, the prong can be removed between 6 and 12 months of age.  相似文献   
8.
B Mookerjee  M O Arcasoy  G F Atweh 《Blood》1992,79(3):820-825
Previous analysis of the hemoglobin phenotype of the K562 human erythroleukemia cell line showed regulated expression of the epsilon-, zeta-, gamma-, alpha-, and delta-globin genes. Expression of the beta-globin genes has not been previously detected in this cell line. In this report, we describe the isolation of a variant of the K562 cell line that actively expresses beta-globin messenger RNA (mRNA) and polypeptide and shows greatly reduced expression of the delta-globin genes. This phenotype developed spontaneously in culture while two other K562 isolates grown under the same culture conditions have not undergone the same delta- to beta-globin switch. Analysis of this unique K562 variant shows that a construct containing a beta-globin promoter is quite active upon transient transfection into these cells. This finding suggests that the activation of the endogenous beta-globin genes results from changes in the trans-acting environment of these cells. The regulation of the beta-globin genes in this variant is characterized by a paradoxical decrease in the level of beta-globin mRNA after exposure to hemin. Other globin genes of this variant are appropriately regulated and show increased expression after hemin induction. Further study of this variant may shed light on mechanisms of gene regulation that are involved in hemoglobin switching.  相似文献   
9.
10.
Patients who have undergone allogeneic bone marrow transplantation (allo-BMT) are susceptible to a variety of opportunistic infectious complications in the months to years after engraftment. Impaired in vitro T-cell functions have been documented in these patients, and these T-cell dysfunctions contribute to the prolonged immune deficiency after allo-BMT. In the present study, we examined the expression of CD26 as well as the reconstitution of CD26-mediated T-cell costimulation via the CD3 and CD2 pathways at various times in patients aged greater than 18 years after CD6-positive, T-cell depleted allo- BMT. We found that the percentage of CD26- and CD3-positive cells, as well as the levels of expression of both antigens, was lower than in normal controls during the first 4 months after CD6-depleted allo-BMT. Subsequently, the amount of lymphocytes expressing CD3 and CD26 and the quantitative surface expression of CD3 and CD26 were not significantly different in patients and normal controls. Functional studies showed that CD26-mediated T-cell proliferation via the CD3 pathway was considerably improved and almost reached normal levels by 1 year, whereas recovery of CD26-mediated T-cell proliferation via the CD2 pathway was delayed for at least 2 years after CD6-depleted allo-BMT. As CD26 involvement in the regulation of human thymocyte activation is restricted preferentially to the CD3 pathway--unlike its involvement with both CD3 and CD2 pathways of peripheral T cells--our results suggest that the different effects of CD26-mediated costimulation via the CD3 and CD2 pathways after CD6-depleted allo-BMT may be a reflection of peripheral T-cell immaturity in those individuals, similar to that seen in mature medullary thymocytes or cord T lymphocytes.  相似文献   
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