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61.
R T Pham M Sung C R Dawson J Schachter 《Investigative ophthalmology & visual science》1990,31(7):1367-1373
The development and testing of candidate vaccines for trachoma are constrained because only humans and nonhuman primates are susceptible to conjunctival infection with Chlamydia trachomatis. Guinea pig inclusion conjunctivitis (GPIC), an analogous disease of guinea pigs, provides a useful, less expensive model to study ocular chlamydial infections. GPIC is caused by a Chlamydia psittaci strain whose external constituents are very similar to those of C. trachomatis. To develop a better model for studying GPIC immunity, conjunctival pockets were established under the abdominal skin of guinea pigs by subcutaneous implantation. Up to six implants could be produced in each animal. The success rate of implantation was 79.0% (n = 148). These pockets were then infected with GPIC. The organism was recovered from the autografts indicating local replication, and tests for serum antibody by microimmunofluorescence showed production of GPIC-specific antibody of IgG and IgM classes after infection. There was minimal antibody response after moderate inoculating doses to the implants, and the titers increased more slowly than after eye infection with GPIC; with higher concentration of the inoculum, however, the antibody response increased to the same levels as with the ocular challenge but more slowly. Inoculation of pockets with GPIC also produced acute inflammatory changes in infected autografts (n = 101). Histologic examination of infected grafts showed chlamydial inclusions in epithelial cells and significant infiltration with lymphocytes and polymorphonuclear cells. Subcutaneous autografts may provide a useful model for chronologic studies of chlamydial infection. The delayed immunologic response, however, suggests that these pockets of implanted epithelium do not have full access to the immune system. 相似文献
62.
Ana Vanson Arthur P. Arnold Barney A. Schlinger 《General and comparative endocrinology》1996,102(3):342-350
3β-hydroxysteroid dehydrogenase/Δ5−Δ4isomerase (3β-HSD) activity was measured in primary dissociated cell cultures prepared from telencephalons of developing zebra finches. 3β-HSD activity was confirmed after cultures were incubated with [7-3H]pregneno- lone (Preg) or (1,2,6,7-3H-) dehydroepiandrosterone (DHEA) and3H-progesterone (Prog) and3H-androstenedione (AE) were detected in the medium. Product identity was confirmed by recrystallizations and by HPLC analysis. When DHEA was used as substrate,3H-estradiol and3H-estrone were also detected in the culture medium, presumably derived from the aromatization of3H-AE or3H-T produced from3H-DHEA. To test this idea, cultures were incubated with3H-DHEA together with radioinert AE or with fadrozole HCl, a potent and specific aromatase inhibitor. In the presence of radioinert AE,3H-AE increased but metabolites of3H-AE decreased in the media; in the presence of fadrozole,3H-estrogens decreased but3H-AE and its androgenic metabolite3H-5β-androstanedione increased. These data demonstrate 3β-HSD activity in the songbird brain. The presence of Prog and estradiol in these cultures suggest that Preg and DHEA can potentially serve as substrates for the ultimate formation of active sex steroids in the songbird telencephalon. 相似文献
63.
Albert R. La Spada MD PhD Arthur W. Clark MD 《Brain pathology (Zurich, Switzerland)》1997,7(3):877-880
At the beginning of this decade, the American Association of Neurology decided that the 1990's should be labelled "the decade of the brain" for expected advances in our understanding of neurological disorders and neuroscience. By the end of this decade, clinicians and researchers who work in the field of inherited neurological disorders might well remember the 1990's as "the decade of the trinucleotide repeat". At the time of writing this introduction, eleven inherited neurological disorders have been found to be caused by expansions of trinucleotide repeats, and a twelfth trinucleotide repeat expansion mutation has been identified (6), although the gene containing this mutant triplet repeat has not been cloned to our knowledge (Table 1). 相似文献
64.
Jin Woo Kim M.D. Ho Shik Kim M.D. In Kyung Kim M.D. Mee Ran Kim M.D. Eun Young Cho B.S. Heung Kee Kim M.D. Joon Mo Lee M.D. Sung Eun Namkoong M.D. 《Gynecologic oncology》1998,69(3):230-236
Transforming growth factor-β1 (TGF-β1) is known to be a potent growth inhibitor for many cell types, including most epithelial cells. In skin keratinocytes, TGF-β1 has been shown to inhibit growth and to rapidly reduce c-mycexpression. However, the molecular mechanism of TGF-β1 action on cell growth of cervical carcinoma has not yet been elucidated. We thus assessed the effect of TGF-β1 on the growth of cervical carcinoma cell lines. Two cervical squamous carcinoma cell lines, CUMC-3 and CUMC-6, were incubated with varying concentrations of TGF-β1, and growth inhibition was evaluated with tetrazolium-based colorimetric assay. After culture in TGF-β1 for 24 h, inhibition of growth was detected in a dose-dependent manner at concentrations of 0.1–10 ng/ml in both cell lines. This effect of TGF-β1 on cultured carcinoma cells was associated with apoptotic process including oligonucleosomal ladder DNA and apoptotic body formations. Northern blot analysis revealed c-mycmRNA expression was suppressed by 10 ng/ml of TGF-β1 following 3 h of treatment in both cell lines. Western blot analysis showed that the level of p27Kip1protein was increased after TGF-β1 treatment in both cell lines. These results suggest that the mechanisms by which TGF-β1 inhibits the growth of cervical carcinoma are complex and may include effects on down-regulation of c-mycgene, and overexpression of p27Kip1protein. 相似文献
65.
扩大的椎板间开窗治疗腰椎间盘突出伴侧隐窝狭窄(附140例报告) 总被引:1,自引:0,他引:1
本组采用的扩大的椎板开窗术治疗腰椎间盘突出合并侧隐窝狭窄140例。结果全部优良,与适应症严格选择和手术损伤小有关。强调切除卡压神经根的侧隐窝后壁外侧,即上关节突的冠状面.不失其脊椎三柱系统的三角结构。俯卧位头低足高,可减少硬膜囊张力避免负损伤。切除棘突下椎板时,用神经拉勾代替神经剥离器易于分离黄韧带,用90度的椎板咬骨钳斜向棘突方向,可满意地切除该部份椎板黄韧带,并可刮切椎板内层。神经根周围滴入醋酸炎舒松A2-3ml,术后疼痛锐减。减压窗口置盖明胶海绵有其争议,作者实践体会放置害处不大,要求病人有“护腰”意识。 相似文献
66.
Yeong Shik Kim Kyung Shin Park Ho Koon Park Sung Whan Kim 《Archives of pharmacal research》1994,17(5):337-342
Carbohydrate analysis is important in studying structure and activity of complex polysaccharides. New analytical method was
applied to get an information on the composition of polysaccharides showing antitumor activity. Monosaccharides were labeled
with 7-amino-1,3-naphthalenedisulfonic acid (7-AGA) by reductive amination and separated by HPLC. Five kinds of polysaccharides
fromBasidiomycetes were hydrolyzed and analyzed in combination with electrophoresis and HPLC. At the same time, alditol acetate derivatives
were prepared and analyzed by gas chromatography. Two different techniques using different derivatization methods showed very
similiar results. The monosaccharides fromCoriolus versicolor andLentinus eodes were mainly composed of D-glucose, while those fromGanoderma lucidium andCordyceps militaris were glucose and galactose.Phellinus linteus composed of glucose, galactose, mannose, arabinose and fucose. The HPLC method with fluorescence detector was very sensitive
compared to other methods. 相似文献
67.
Elisabeth L George Leslie A Hoffman Arthur Boujoukos Thomas G Zullo 《American journal of critical care》2002,11(1):65-75
BACKGROUND: Many benefits and adverse effects of positioning are related to changes in ventilation and perfusion. A number of unique factors related to the allograft make the effects of positioning difficult to determine in single-lung transplant recipients. OBJECTIVES: To determine the effect of 3 body positions (supine, lateral with allograft lung down, and lateral with native lung down) on oxygenation and blood flow in single-lung transplant recipients in the 24 hours immediately after surgery. METHODS: A quasi-experimental repeated-measures design with stratified assignment to 1 of 3 different sequencing patterns for turning group was used to study 15 transplant recipients, 9 with emphysema and 6 with fibrosis. Oxygenation, ventilation, and blood flow measures (heart rate, blood pressure) were assessed after each turn. The effect of ischemic reperfusion injury was also explored. RESULTS: The oxygenation, ventilation, and bloodflow variables did not differ significantly across group, diagnosis, or time. Oxygenation variables measured when the allograft lung was dependent did not differ significantly from such measurements obtained when the native lung was dependent. CONCLUSIONS: No single position maximizes oxygenation in the immediate postoperative period in single-lung transplant recipients. Although a single standard protocol for positioning cannot be supported, the study does support the idea that transplant recipients can be safely turned in the immediate postoperative period without compromising oxygenation or hemodynamic status. 相似文献
68.
Evidence for in vivo incorporation of D-lactate into peptidoglycan precursors of vancomycin-resistant enterococci. 总被引:8,自引:0,他引:8 下载免费PDF全文
M Arthur C Molinas T D Bugg G D Wright C T Walsh P Courvalin 《Antimicrobial agents and chemotherapy》1992,36(4):867-869
The VanA ligase encoded by the vancomycin resistance plasmid pIP816 of Enterococcus faecium BM4147 condenses D-alanine with various D-2-hydroxy and D-2-amino acids in vitro. D-Lactate added to the culture medium restored the vancomycin resistance of a strain that does not produce the VanH dehydrogenase and therefore appears to be a substrate of VanA in vivo. 相似文献
69.
70.
Peter Van Gelder Sergey Lebedev Wai Hon Tsui 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1997,116(2):201-215
Smooth pursuit typically includes corrective catch-up saccades, but may also include such intrusive saccades away from the
target as anticipatory or large overshooting saccades. We sought to differentiate catch-up from anticipatory and overshooting
saccades by their peak velocities, to see whether the higher velocities of visually rather than nonvisually guided saccades
in saccadic tasks may be found also in saccades in pursuit. In experiment 1, 12 subjects showed catch-up, anticipatory, and
overshooting saccades to comprise 70.4% of all saccades in pursuit of periodic, 30°/s constant-velocity targets. Catch-up
saccades were faster than the others. Saccadic tasks were run as well, on 19 subjects, including the 12 whose pursuit data
were analyzed, with target-onset, target-remaining (saccade to the remaining target when the other three extinguish), and
antisaccade tasks. For 17 of the 19 subjects, antisaccade velocities were lower than for either target-onset or target-remaining
tasks. Velocities for the target-remaining task were near those for target onset, indicating that target presence, not its
onset, defines visually guided saccades. Error and reaction-time data suggest greater cognitive difficulty for target remaining
than for target onset, so that the cognitive difficulty of typical nonvisually guided saccade tasks is not sufficient to produce
their lowered velocity. To produce reliably, in each subject, catch-up and anticipatory saccades with comparable amplitude
distributions, nine new subjects were asked in experiment 2 to make intentional catch-up and anticipatory saccades in pursuit,
and were presented with embedded target jumps to elicit catch-up saccades, all with periodic target trajectories of 15°/s
and 30°/s. Velocities of intentional anticipatory saccades were lower than velocities of intentional catch-up saccades, while
velocities of intentional and embedded catch-up saccades were similar. Target-onset and remembered-target saccadic tasks were
run, showing the expected higher velocity for the target-onset task in each subject. Both experiments demonstrate higher peak
velocities for catch-up saccades than for anticipatory saccades, suggesting that cortical structures preferentially involved
in nonvisually guided saccades may initiate the anticipatory and overshooting saccades in pursuit.
Received: 1 December 1995 / Accepted: 25 February 1997 相似文献