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排序方式: 共有709条查询结果,搜索用时 31 毫秒
1.
神经生长因子对小鼠突触体内Ca^2+水平的调节作用 总被引:4,自引:1,他引:3
观察了多次海马内微注射NGF对小鼠突触体内游离钙水平的影响,并在离体情况下观察NGF对EGTA和CaCl2分别造成突触体内低钙和高钙状态的调节作用。结果如下:(1)在体实验表明,一定剂量的NGF可显著降低老年小鼠海马突触体内游离钙水平(P<005);(2)离体实验表明,当突触体游离钙水平降低时,适当剂量的NGF具有升高游离钙水平的作用;而突触体内游离钙水平升高时,则NGF有降低游离钙水平的作用。提示NGF对游离钙水平的双向调节作用可能是NGF改善老年性记忆衰退的作用机制。 相似文献
2.
E A Wanek J G Horgan F M Karrer R J Hall C M Rumack J R Lilly 《Journal of pediatric surgery》1990,25(1):146-148
From December 1986 to April 1989, 38 patients with biliary atresia (eight newly diagnosed) were evaluated with doppler ultrasound of the portal venous system. Peak and mean velocities were computer derived from the spectral waveform. Good velocity was greater than 15 cm/s, intermediate velocity was 8 to 14 cm/s, abnormal velocity was less than 7 cm/s or hepatofugal. Patients were grouped according to clinical status: group 1 (n = 14), normal liver function; group 2 (n = 15), recurrent cholangitis; group 3 (n = 2), established bile drainage but complicated cirrhosis; group 4 (n = 7), failed portoenterostomy. All patients with normal liver function (group 1) had good or intermediate velocities. Thirteen of 15 patients with recurrent cholangitis (group 2) had good or intermediate velocities. Both patients in this group with abnormal velocities required transplantation. In group 3 the patient with abnormal velocity is on the transplant waiting list. In group 4, abnormal velocities preceded or coincided with deterioration of liver function in five of seven patients. Doppler ultrasound provides useful anatomic information, determines direction of flow, quantitates velocity of flow, and, when performed serially, provides adjunctive information on liver status in children with biliary atresia. These preliminary results suggest that patients with abnormal or significantly decreasing velocity are destined for transplantation. Patients with good portal venous velocity warrant ongoing, aggressive surgical management. 相似文献
3.
MY Mancao LJ Sindel PH Richardson FM Silver 《Acta paediatrica (Oslo, Norway : 1992)》1996,85(1):118-120
Croup is an acute infectious illness usually occurring in children; it is characterized by brassy cough and stridor. The main pathogens include mainly parainfluenza and influenza viruses. Recently there have been reports of prolonged croup caused by the herpes simplex viruses. We report two cases of prolonged croup due to herpes simplex types 1 and 2. We also review and summarize the reported pediatric cases of herpetic croup. 相似文献
4.
J R Lilly F M Karrer R J Hall G P Stellin J J Vasquez-Estevez S K Greenholz E A Wanek G P Schroter 《Annals of surgery》1989,210(3):289-94; discussion 294-6
One hundred thirty-one consecutive infants with biliary atresia were operated on during the 15-year period between 1973 and 1988. Six patients did not have biliary reconstruction because of advanced cirrhosis or transplant preference. The other 125 infants had excision of all nonpatent extrahepatic bile ducts; biliary drainage was provided by a gallbladder-common bile duct conduit in 14 patients and by a Roux-en-Y portoenterostomy in 111 infants (including the seven patients with correctable biliary atresia). The bilioenteric conduit was temporarily exteriorized and, for the past 2 years, a conduit intussusception valve was incorporated. Immediate postsurgical bile drainage was achieved in 103 infants (82%). Reoperation during the first 6 postoperative weeks restored bile flow in 14 of 18 infants who had shut down. Seventy-two patients (57%) had sustained (more than 1 year) relief of biliary obstruction. Postoperative morbidity was substantial. The six children not having corrective surgery died within 19 months. Three patients were lost to follow-up. Sixty-eight patients having Kasai's operation died, 55 from complications of liver disease, 1 from a coexisting malformation, and 12 after liver transplantation. Fifty-seven patients are alive, 13 by virtue of liver replacement, 9 with mild-to-moderate hepatic sequelae, and 35 (28%) with normal to near-normal liver function. Although none is considered "cured," the 35 children are anicteric, have normal growth and development, and participate in full school activities (including contact sports). Average follow-up is 85.8 months (range 1 to 15 years). 相似文献
5.
Duncan WC; Illingworth PJ; Young FM; Fraser HM 《Human reproduction (Oxford, England)》1998,13(9):2532-2540
The molecular mechanisms involved in luteolysis are still unclear in the
primate. This study aimed to investigate the effect of induced luteolysis
on the ovarian luteinizing hormone (LH) receptor and the steroidogenic
enzyme, 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the marmoset
monkey. Luteolysis was induced in the mid-luteal phase either directly by
systemic prostaglandin F2alpha (PGF2alpha), or indirectly by LH withdrawal
using systemic gonadotrophin releasing hormone antagonist (GnRHant)
treatment. The LH receptor was studied by isotopic mRNA in-situ
hybridization and in-situ ligand binding and 3beta-HSD expression was
studied using isotopic mRNA in-situ hybridization and immunohistochemistry.
Induced luteolysis was associated with a reduction in the expression of LH
receptor (P < 0.0001) and 3beta-HSD mRNA, closely followed by a
reduction in the LH receptor (P < 0.05) and 3beta-HSD protein
concentrations within 24 h. There were no differences in the findings
whether luteolysis was induced with PGF2alpha or GnRHant. This study shows
that disparate mechanisms to induce luteolysis in the primate result in an
identical rapid loss of the LH receptor and 3beta-HSD. In conclusion,
induced luteolysis leads to rapid loss of the steroidogenic pathway in
luteal cells.
相似文献
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9.
Transition metal complexes containing vanadium IV have been shown to
modulate the cellular redox potential and catalyse the generation of
reactive oxygen intermediates (ROI). Since sperm function is exquisitely
susceptible to ROI, we examined the effects of stable chelate complexes of
vanadocenes on human sperm motility. We synthesized seven structurally
distinct chelate complexes of bis(cyclopentadienyl)vanadium(IV) with
bidentate ligands [i.e. vanadocene acetylacetonato monotriflate (VDacac),
vanadocene hexafluoro acetylacetonato monotriflate (VDHfacac), vanadocene
N-phenyl benzohydroxamato monotriflate (VDPH), vanadocene acethydroxamato
monotriflate (VDH), vanadocene catecholate (VDCAT), vanadocene bipyridino
ditriflate (VDBPY), and vanadocene dithiocarbamate monotriflate (VDDTC)],
and evaluated their spermicidal activity using computer-assisted sperm
analysis (CASA; Hamilton-Thorne). All seven chelate complexes of vanadocene
elicited potent spermicidal activity at micromolar concentrations (EC50
values: 3.9-106 microM) without affecting the sperm acrosome integrity. The
catecholate and acetylacetonate complexes of vanadocene were the most
active and the bipyridyl complex the least active with an order of efficacy
VDCAT > VDacac > VDDTC > VDPH > VDH > VDHfacac > VDBPY.
The spermicidal activity of chelate complexes of vanadocenes was rapid and
irreversible since the treated spermatozoa underwent apoptosis, as
determined by the flow cytometric analysis of mitochondrial membrane
potential, surface annexin V binding assay, in-situ nick-end labelling of
sperm nuclei, and confocal laser scanning microscopy. These results provide
unprecedented evidence that chelate complexes of vanadocene with bidentate
ligands have spermicidal and apoptosis inducing properties. These
vanadocene complexes, especially VDacac, may be useful as contraceptive
agents.
相似文献
10.
Three monkeys with travel vision and 5 controls were observed with their mothers during the first 6 months of age and then for another 3 months after they had been placed in social isolation. In the home cage, the experimental animals did not differ from controls except that two held a hand before their eyes in a stereotyped fashion not previously reported for animals. In an unfamiliar environment the blind animals did not look at an observer, threatened less than normal, and were awkward in moving around. Animals who held hands before eyes tended to approach a flickering visual stimulus. 相似文献