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Intrastriatal grafts of fetal ventral mesencephalon in rats with unilateral 6-hydroxydopamine lesions can reduce and even reverse rotational behavior in response to direct and indirect dopamine agonists. These grafts can ameliorate deficits on simple spontaneous behaviors, but do not improve complex behaviors that require the skilled integration of the use of both paws. We report here that rats with grafts into the DA-depleted substantia nigra, that receive cyclosporine A, can experience recovery on spontaneous behaviors that mimic those observed in Parkinson's disease. Specific cyclosporine A treatment conditions can differentially affect whether intranigral grafts normalize paw use during initiation or termination of a movement sequence. These findings may have important implications for the treatment of Parkinson's disease. 相似文献
43.
Gastrin-releasing peptide (GRP) causes multiple effects in humans by activating a specific heptaspanning receptor. Within the gastrointestinal tract, GRP receptors (GRP-R) are not normally expressed by mucosal epithelial cells except for those lining the gastric antrum. In contrast, recent studies have shown that up to 40% of resected colon cancers aberrantly express this receptor. This is important because the GRP-R can cause the proliferation of many, but not all, tissues in which it is expressed. Since GRP and other agonists are not known to exist in the colonic lumen, it has not been clear how or even if GRP-R expression in colon cancer contributes to cell proliferation. To evaluate the functional consequence of GRP-R expression on colonic epithelium, we transfected the recently isolated nonmalignant human colon epithelial cell line NCM460 with the cDNA for this receptor. All NCM460 cell lines expressing varying numbers of GRP-R bound selected agonists and antagonists indistinguishably from receptors expressed by other human tissues. Furthermore GRP-R-expressing transfected cell lines, but not wild-type NCM460 cells, proliferated independently of serum or other growth factors. Further evaluation revealed that GRP-R in these cells tonically stimulated G alpha q/11, resulting in increased phospholipase C activation. Since transfected cells do not secrete GRP, nor is their growth influenced by exposure to receptor-specific antagonists, these data indicate that GRP-R ectopically expressed by NCM460 cells are constitutively active. This report provides the first evidence of mutation-independent heptaspanning receptor constitutive activation resulting in cell proliferation, and identifies a potential mechanism whereby the GRP-R may act as an oncogene in human colon cancer. 相似文献
44.
A Anthony AP Dhillon RE Pounder AJ Wakefield 《Canadian Metallurgical Quarterly》1997,50(12):1013-1017
Forty-five cases of gastroschisis and 85 of omphalocele were reviewed. The survival of gastroschisis has dramatically improved over the past 20 years, however, that of omphalocele still remained in the lower value, because the size of the defect and the presence of associated anomalies are prognostic factors. The primary fascial closure was first employed for the patients with gastroschisis and a silo chimney was used for limited cases. On the other hand, for the patients with omphalocele, primary closure was possible in 34 cases, silo chimney was used in 17, and 45 cases had nonoperative management with epithelialization. Among them, nonoperative management using painting was the most reliable therapeutic for omphalocele. 相似文献
45.
HZ Hill GJ Hill K Cieszka PM Plonka DL Mitchell MF Meyenhofer P Xin RE Boissy 《Canadian Metallurgical Quarterly》1997,65(6):983-989
PURPOSE: This study reports the authors' experience with long-term follow-up of 100 consecutive peripherally inserted, subcutaneous arm ports for central venous access. MATERIALS AND METHODS: One hundred patients with subcutaneous arm ports inserted by interventional radiologists were retrospectively studied. Data were collected from the patients' medical records and from telephone canvassing. Using each insertion period as an observation, the complication rates per 100 catheter days were determined with 95% confidence intervals (CIs). RESULTS: One hundred subcutaneously implanted ports were placed in 98 patients; three devices (three patients) were lost to follow-up, leaving 97 devices in 95 patients. Total exposure time was 23,842 days (mean, 246 days; range, 2-865 days). Seven infectious and two noninfectious complications occurred with seven (7.2%) devices in six patients (6.3%), yielding 0.038 complications per 100 catheter days at risk (95% CI; 0.011-0.069) and 0.029 infections per 100 catheter days at risk (95% CI; 0.008-0.058). A successful clinical outcome was defined as a functional port at removal, time of death, or at study closure (minimum of 6 months of follow-up), which was not removed because of a complication. This successful outcome was achieved in 91 ports (93.8%). Procedural-related complications, defined as those occurring up to 30 days after insertion, occurred in only one port (thrombophlebitis and catheter tip infection-day 9). All other patients received several months of service from their port. Fifteen devices were placed in 13 patients with HIV for 3,486 days, with a total complication rate of 0.11 per 100 catheter days (95% CI; 0.0-0.28), all of which were infections. Devices in HIV-positive patients were associated with higher total complication (20% vs 4.9%) and infection rates (20% vs 3.7%) than devices in patients without HIV infection. This gives a relative risk 8.17 x (P = .04) greater for infectious complications for devices placed in HIV-infected individuals. CONCLUSIONS: Subcutaneous arm ports placed by interventional radiologists are effective for central venous access with excellent functionality (93.8% achieved a successful long-term outcome) and a very low procedural complication rate. Although infections were more frequent in HIV-infected individuals, these devices are associated with a very low incidence of both immediate and long-term complications, including infection, for all patients. 相似文献
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Few studies have been directed toward elucidating the action of calcitonin (CT) and parathyroid hormone (PTH) on growth plate chondrocytes, cells directly involved in longitudinal bone growth and provisional calcification. In this study, primary cultures of avian growth plate chondrocytes that calcify without the supplement of beta-glycerophosphate were used to investigate the effects of synthetic human CT and 1-34 bovine PTH on (1) cell division and growth; (2) the deposition of Ca2+ and inorganic phosphate (Pi); (3) the activity of alkaline phosphatase (AP), an enzyme long associated with the mineralization process; (4) the levels of proteoglycans; and (5) the synthesis of collagens. Added continually to preconfluent cultures from day 6 until harvest, CT (1-30 nM) and PTH (0.1-1.0 nM) increased mineral deposition; the maximal increase was seen between days 18-21 at 10 nM CT (175-260%) and 0.5 nM PTH (approximately 170-280%), both p < 0.001. CT had no significant effect on cellular protein, or AP-specific activity, whereas PTH increased cellular protein, DNA, proteoglycan, and collagen content of the cultures in a dosage-dependent manner. AP activity and levels of Type II and X collagens and fibronectin in the culture medium showed a biphasic response to PTH; maximal increases were seen at 0.5 nM between days 15-18. Longer exposure (days 21-27) to PTH at higher levels (5-10 nM) caused a marked decreased in AP activity but a lesser decrease in the collagens. These results indicate that CT and PTH can act directly on chondrocytes to stimulate mineralization, but that PTH specifically stimulated cell division and synthesis of cellular and extracellular proteins by growth plate chondrocytes. The implications of these findings with regard to Ca2+ homeostasis and bone formation are discussed. 相似文献
49.
Improvements on a localized, automatic shimming method described by Gruetter and Boesch (J. Magn. Reson. 96, 323-334 (1992)) and Gruetter (Magn. Reson. Med. 29, 804-811 (1993)) are presented. A spin-echo sequence employing a double sech refocusing scheme is used to acquire a field map along linear projections that improves the signal-to-noise ratio by at least a factor of two over the stimulated echo sequence previously used. To further improve the reliability of shim adjustments, a variance-weighted polynomial regression analysis is performed. This also extends the scope of application of this technique to global shimming. Localized 1H spectra of human brain shimmed by this method are presented. 相似文献
50.
RE progress: 《Refocus》2002,3(4):30
For 300 years, Europe was dotted with windmills - around 10,000 in Britain alone. Our predecessors understood instinctively that renewables were there, freely available for harnessing, and would never run out. Had these installations been able to raise their game with higher efficiencies and work in the ‘common currency’ of electricity, we might have avoided the excesses of centralisation that led to consumers receiving their power from mere handfuls of fossil (and later nuclear)-fuelled power stations. 相似文献