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31.
S. Hering D. J. Beech T. B. Bolton S. P. Lim 《Pflügers Archiv : European journal of physiology》1988,411(5):590-592
The actions of nifedipine or BAY K 8644 were studied on barium currents recorded from single, collagenase- and elastase-dispersed, smooth muscle cells from the rabbit ear artery using the whole-cell configuration of the patch-clamp technique. Nifedipine (3M) caused a reduction in the barium current (IBa) evoked by steps to potentials positive of-10mV. This was characterized by a pronounced initial block, an increase in the rate of current decay during the voltage-clamp step, but by no increase in block if pulses were repeated every 600ms. Rapid extracellular application of nifedipine (1M) during the sustained current component (using a new concentration-jump technique) was found to have no effect on IBa over 4s at +20mV, but after returning to the holding potential (-60mV) for 10s, sustained IBa was subsequently abolished. BAY K 8644 (1M) increased IBa at all potentials, and on rapid application during the sustained current component markedly potentiated IBa. The results suggest that nifedipine binds with high affinity to the closed, available state of the Ca++ channels but they do not suggest binding to the open or inactivated states. The effect of BAY K 8644 is consistent with high affinity binding to the open or inactivated and to the closed, available states. 相似文献
32.
33.
Philip S. Bolton David J. Tracey 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1992,92(1):59-68
Summary Experiments were performed on rats to determine whether primary afferents from the upper cervical region terminate directly on Spinothalamic and propriospinal neurones. The central terminations of primary afferents from the upper cervical region were identified by diffusely filling their axons with horseradish peroxidase. Spinothalamic neurones or propriospinal neurones were identified in the same experimental animals by using retrograde transport of wheat germ agglutinin conjugated to horseradish peroxidase. Approximately 3–11 % of Spinothalamic cells in laminae 4–6 of spinal segments C2–4 received apparent synaptic contacts from primary afferents on the soma or primary dendrites. Approximately 18–36% of propriospinal neurones with axons descending to lower thoracic or lumbar levels received apparent synaptic contacts on the soma or primary dendrites. These data provide anatomical evidence that Spinothalamic and long propriospinal neurones in the upper cervical cord are excited directly by primary afferents. The data also help to clarify the neural circuitry underlying somatic sensation and reflex movements evoked by neck receptors. 相似文献
34.
F. J. Bolton D. Coates 《European journal of clinical microbiology & infectious diseases》1983,2(2):105-110
The relative ability of two commercial gas generating envelopes, the evacuation-replacement technique, and a candle jar, to produce a satisfactory microaerobic atmosphere for the culture of 45Campylobacter strains on non-selective medium and five selective media (Skirrow's, modified Butzler's, Blaser's, Campy-BAP and Preston medium) was investigated quantitatively. A candle jar, and modified Butzler's medium proved to be of limited use. The ability of four commercial gas generating envelopes to produce a satisfactory microaerobic atmosphere in four anaerobic jars of different volume was investigated using five referenceCampylobacter strains. Not all of the combinations worked. The oxygen and carbon dioxide concentrations produced in the microaerobic systems studied were measured with gas analysers. The evacuation-replacement technique produced far less variable concentrations of oxygen and carbon dioxide than did the envelopes. 相似文献
35.
Blood-free selective medium for isolation of Campylobacter jejuni from feces 总被引:4,自引:6,他引:4
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A blood-free selective agar is described which contains charcoal, ferrous sulfate, sodium pyruvate, casein hydrolysates, cefazolin, and sodium deoxycholate (CCD agar). CCD agar was compared with Preston medium for isolation of Campylobacter jejuni from human feces, and isolation rates were similar on both media, but CCD agar was less selective. Temperature studies at 37 and 42 degrees C confirmed that incubation of direct plates at 42 degrees C for 48 h was necessary for maximum isolation of C. jejuni. 相似文献
36.
Bolton Virginia N.; Braude Peter R.; Ockenden Kim; Marsh Simon K.; Robertson Gregory; Ross Leslie D. 《Human reproduction (Oxford, England)》1989,4(6):674-679
Twenty-nine couples with an average of 5 years of infertilitywere selected for treatment by intrauterine insemination ofwashed semen (AIH). The criteria for selection were (i) thefemale partner showed no detectable fertility disorders by routinescreening; (ii) the male partner showed subnormal semen qualityon conventional semen analysis. Ovulation was stimulated uniformlywith clomiphene citrate and precipitated with human chorionicgonadotrophin (HCG). Inseminations were performed 3132h post-HCG, with the day of HCG determined by ultrasound monitoringof follicular development. The fertilizing capacity of the malepartners spermatozoa was tested in vitro using donatedhuman oocytes and/or the zona-free hamster oocyte penetrationassay. Up to eight cycles of AIH were alternated with cyclesof natural intercourse. While no pregnancies occurred in thegroup during normal coital cycles, the AIH pregnancy rate was17% per couple, but only 3% per insemination cycle. Four furtherpregnancies were achieved spontaneously in couples from thestudy group within 3 years of completion of the AIH therapyand four patients became pregnant following subsequent GIFTor IVF treatments. Neither of the in-vitro tests was helpfulin predicting the outcome of AIH, spontaneous pregnancy norof subsequent assisted conception procedures. 相似文献
37.
Preimplantation genetic diagnosis principles and ethics 总被引:4,自引:0,他引:4
38.
Life expectancy in British Marfan syndrome populations 总被引:2,自引:0,他引:2
JR Gray AB Bridges RR West L. McLeish AG Stuart JCS Dean MEM Porteous M. Boxer SJ Davies 《Clinical genetics》1998,54(2):124-128
A total of 206 patients with Marfan syndrome were ascertained throughout genetic clinics in Wales and Scotland during the period 1970–1990. There were 45 deaths representing 22% of the cohort. Mean age at death was 45.3 ± 16.5 years. 50% median cumulative survival in the total cohort (n = 206) was 53 years for males and 72 years for females. Multivariate analysis confirmed severity as the best independent indicator of survival. These findings and survival curves will assist in the counselling of British families and individuals with Marfan syndrome. 相似文献
39.
Frataxin is reduced in Friedreich ataxia patients and is associated with mitochondrial membranes 总被引:17,自引:8,他引:17
Campuzano V; Montermini L; Lutz Y; Cova L; Hindelang C; Jiralerspong S; Trottier Y; Kish SJ; Faucheux B; Trouillas P; Authier FJ; Durr A; Mandel JL; Vescovi A; Pandolfo M; Koenig M 《Human molecular genetics》1997,6(11):1771-1780
Friedreich ataxia is a progressive neurodegenerative disorder caused by
loss of function mutations in the frataxin gene. In order to unravel
frataxin function we developed monoclonal antibodies raised against
different regions of the protein. These antibodies detect a processed 18
kDa protein in various human and mouse tissues and cell lines that is
severely reduced in Friedreich ataxia patients. By immunocytofluorescence
and immunocytoelectron microscopy we show that frataxin is located in
mitochondria, associated with the mitochondrial membranes and crests.
Analysis of cellular localization of various truncated forms of frataxin
expressed in cultured cells and evidence of removal of an N-terminal
epitope during protein maturation demonstrated that the mitochondrial
targetting sequence is encoded by the first 20 amino acids. Given the
shared clinical features between Friedreich ataxia, vitamin E deficiency
and some mitochondriopathies, our data suggest that a reduction in frataxin
results in oxidative damage.
相似文献
40.
Adequate hemodialysis schedule 总被引:1,自引:0,他引:1
J R De Palma C F Bolton M A Baltzan R B Baltzan 《The New England journal of medicine》1971,285(6):353-354