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81.
82.
83.
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:3,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
84.
We report the successful long-term engraftment of normal male donor bone marrow (BM) transfused into noncytoablated female mice, challenging the assumption that "niches" need to be created for marrow to engraft. We have used chromosomal banding and Southern blot analysis to identify transplanted male marrow cells, and shown the long-term stability of the chimeric marrows. Balb/C, BDF1, or CBA-J female hosts (no irradiation) received for 5 consecutive days 40 x 10(6) male cells (per day) of the same strain, and repopulation patterns were observed. Parallel studies were performed using tibia/femur equivalents of normal marrow or marrow from Balb/C mice pretreated 6 days previously with 150 mg/kg 5-fluorouracil (5-FU). Chromosome banding techniques showed that 5% to 46% of marrow cells were male 3 to 9 months posttransplant with normal donor marrow. Southern blot analysis, using the pY2 probe, showed continued engraftment at 21 to 25 months posttransplant, ranging from 15% to 42% male engrafted cells in marrow. Normal donor male marrow engrafted significantly better than 5-FU-pretreated male marrow as shown 1 to 12 months posttransplant in non-cytoablated female recipients. Percentages of male engrafted cells in BM ranged from 23% to 78% for recipients of normal donor marrow and from 0.1% to 39% for recipients of 5-FU marrow. Mean engraftment for 6 mice receiving normal marrow was 38%, whereas that for 6 mice receiving post-5-FU marrow was 8%, as assayed 1 to 3 months posttransplant. At 10 to 12 months, mean engraftment for the normal donor group was 46%, compared with 16% for the 5-FU group. The patterns of engraftment with normal and 5-FU marrow were similar for spleen and thymus. These results show that long-term chimerism can be established after transplantation of normal donor marrow to normal nonirradiated host mice and indicate that marrow spaces do not have to be created for successful engraftment. They suggest that transplanted marrow competes equally with host marrow for marrow space. Finally, these data show that post-5-FU Balb/C male marrow is markedly inferior in the repopulation of Balb/C female host marrow, spleen, and thymus, and suggest that this population of cells may not be the ideal population for gene transfer studies. 相似文献
85.
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
86.
Obstruction of the small intestine: accuracy and role of CT in diagnosis 总被引:17,自引:0,他引:17
Maglinte DD; Gage SN; Harmon BH; Kelvin FM; Hage JP; Chua GT; Ng AC; Graffis RF; Chernish SM 《Radiology》1993,188(1):61
87.
The acrosome reaction is an important marker for human sperm function.
Since different laboratory techniques may be used for the detection of this
exocytotic process, the purpose of the present study was to compare three
common markers [Pisum sativum agglutinin (PSA), concanavalin A (ConA),
double staining] and transmission electron microscopy for identification of
acrosomal changes. Preliminary findings had demonstrated that similar
results were achieved with Trypan Blue and Hoechst 33258 staining.
Therefore, supravital stainings were omitted. In various experiments, human
spermatozoa were treated with two concentrations (10 and 3.3 microM) of
calcium ionophore A23187 for 15, 30 and 60 min after capacitation for 3 and
6 h at 37 degrees C. The percentages of spermatozoa with acrosomal loss
detected by fluorescein isothiocyanate (FITC)-ConA were consistently lower
than those obtained by double staining or FITC-PSA, which showed comparable
results. Following 6 h of capacitation and incubation with 10 microM
ionophore for 1 h at 37 degrees C, 25.9 +/- 15.7% of all spermatozoa showed
almost complete loss of the acrosomal content. Binding of FITC- ConA to the
acrosomal region was observed in 27.0 +/- 13.2% of spermatozoa obtained
from the same sample. FITC-ConA and double staining or FITC-PSA detect
different stages of the acrosome reaction and may be helpful for a
differentiated evaluation of this sperm function.
相似文献
88.
89.
Manneschi L ° Battisti C Pesci I° Malandrini A° Santorelli FM Scaglioni A° Federico A Montanari E° . 《Journal of the peripheral nervous system : JPNS》2004,9(2):123-123
Charcot‐Marie‐Tooth disease constitutes a clinically and genetically heterogeneous group of hereditary motor and sensory peripheral neuropathies. On the basis of electrophysiologic properties and histopathology, CMT has been divided into demyelinating (type 1) and axonal (type 2) neuropathies. The form of Charcot‐Marie‐Tooth neuropathy that maps to Xq13 may present mild electrophysiological changes (NCV > 40 M/s), mixed neuropathy (NCV: Intermediate (30–40 M/s), or demyelinating neuropathy (NCV: Slow (<37 M/s). On molecular grounds, CMTX is caused by mutations in GJB1 gene, coding for Connexin 32 protein. A 42‐year‐old man, with no other affected family members, was clinically evaluated for CMT. Three years ago he noticed thumb abductor atrophy and then leg muscle atrophy. He presented with hand and leg muscle atrophy, bilateral pes cavus, areflexia, and apallesthesia. The median and ulnar motor NVC were 35–38 m/s, and the median sensory NVC was 35 m/s. Both motor and sensory nerve action potentials were markedly reduced. After exclusion of CMT1A and 1B, analysis for CMTX was performed. The mutation screening of GJB1 gene showed a 9bp insertion upstream the 194ATG codon (Met194) with preservation of the downstream sequence. The three new amino acids (Thr‐Val‐Phe) inserted are localized between the end of the second extracellular domain and the beginning of the fourth transmembrane domain. This is the first 9bp insertion found in GJB1 gene; a genotype‐phenotype correlation may be deduced. 相似文献
90.
Cutaneous leiomyosarcoma typically presents as solitary, well‐circumscribed, firm plaques or nodules. We describe a case of cutaneous leiomyosarcoma clinically presenting as a skin tag on the thigh of a 50‐year‐old male. Histological examination of the lesion revealed a dome‐shaped tumor with interlacing fascicles of smooth muscle with pleomorphism, cellular atypia and multiple mitoses. Malignant tumors may rarely present as a skin tag, and these are most frequently basal cell carcinomas. We are unaware of previously reported leiomyosarcoma clinically presenting as a skin tag. This case suggests that solitary, wide‐based, papilloma‐like lesions or skin tags should be submitted for histologic examination to rule out malignancy. 相似文献