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排序方式: 共有10000条查询结果,搜索用时 31 毫秒
111.
Alon Peled Ofer Sarig Guangping Sun Liat Samuelov Chi A. Ma Yuan Zhang Tom Dimaggio Celeste G. Nelson Kelly D. Stone Alexandra F. Freeman Liron Malki Lucia Seminario Vidal Latha M. Chamarthy Valeria Briskin Janan Mohamad Mor Pavlovsky Jolan E. Walter Joshua D. Milner Eli Sprecher 《The Journal of allergy and clinical immunology》2019,143(1):173-181.e10
112.
BACKGROUND: Earlier studies demonstrated a small temperature difference between the sperm storage and fertilization sites within the oviducts of rabbits and pigs. Our aim was to reveal the time dependence of this temperature difference relative to ovulation, and to determine how this difference is generated-by temperature elevation at one of these sites or by temperature decrease at the other site. METHODS: The temperature at the sperm storage site (at the isthmus near the uterotubal junction) and at the fertilization site (the isthmic-ampullary junction) of rabbit oviducts were measured before, during, and after ovulation by two probes, connected to digital thermometers. Rectal temperature was constantly measured and served as a control for body temperature. RESULTS: The temperature difference between the fertilization site and the storage site was 0.8+/-0.2 degrees C before ovulation. This difference increased at ovulation, reaching 1.6+/-0.1 degrees C after ovulation (P<0.03). This increased difference was mainly due to temperature decrease in the sperm storage site. CONCLUSION: The temperature-difference increase within the rabbit oviduct is generated at ovulation by a reduced temperature at the sperm storage site. This temperature gradient may play a role in mammalian reproduction via sperm thermotaxis. 相似文献
113.
Carlo M. Pesce Rosanna Colacino 《Virchows Archiv : an international journal of pathology》1987,412(2):151-154
Summary The volume of the adenomatous mucosa (V), the area of the surface epithelium (Ss), the area of the glandular epithelium (Sg), and theSg:Ss ratio were calculated in a series of 14 adenomatous polyps (APs) of a case of multiple polyposis of the colon. The equation of simple allometry was used to study the relative growth of the four series of values.Ss grew isometrically with size;Sg overgrewSs and accounted for most of the increase inV. TheSg:Ss ratio increased withSg andV. 相似文献
114.
Vitronectin-mediated inhibition of complement: evidence for different binding sites for C5b-7 and C9. 总被引:2,自引:1,他引:2
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L Milis C A Morris M C Sheehan J A Charlesworth B A Pussell 《Clinical and experimental immunology》1993,92(1):114-119
In the activated complement system, vitronectin (complement S-protein) occupies the metastable membrane binding site of the nascent precursor complex C5b-7, so that the newly formed SC5b-7 is unable to insert into cell membranes. Some evidence also indicates that vitronectin limits on-going membrane-associated pore formation by inhibiting C9 polymerization. It has been assumed that these two stages of terminal complement complex (TCC) inhibition take place through charge interactions between the heparin-binding region of vitronectin and homologous cysteine-rich sequences of the late complement proteins C6, C7, C8 and C9. We examined SC5b-7 formation and inhibition of C9 binding in the TCC using separate haemolytic assays. The mode of action of vitronectin in these assays was compared with two 15mer peptides which span residues 348-379 of the heparin-binding region, and a heparin-affinity polypeptide, protamine sulphate. The results showed that vitronectin acts predominantly through SC5b-7 production with a lesser effect on the inhibition of C9 lytic pore formation. In contrast, protamine sulphate did not prevent C5b-7 membrane attachment, but was a potent inhibitor of C9-mediated lysis. The peptides did not inhibit C5b-7 membrane insertion and only one affected C9 binding. These data suggest that the two stages of TCC inhibition involve separate binding sites on the vitronectin molecule. The site for association with nascent C5b-7 is unknown, whereas inhibition of C9 binding and pore formation takes place through the heparin-binding region. 相似文献
115.
目的探讨医学网络资源的一般获取技巧,以及医学影像学资源的获取途径。方法应用因特网等关键词,采用医学专业检索引擎Medical Matrix,并在此基础上链接其他医学检索引擎,获得有关医学影像学文献的网址和相关网页。结果网上有一些专门的医学影像学资源网站,在高等医学院校和医学科研机构中经常包含医学影像学的资源。结论本文具体阐述了医学影像学资源的获取途径和技巧。 相似文献
116.
Mittal N Zhou Y Ung S Linares C Molloi S Kassab GS 《Annals of biomedical engineering》2005,33(8):1015-1026
A rigorous analysis of blood flow must be based on the branching pattern and vascular geometry of the full vascular circuit
of interest. It is experimentally difficult to reconstruct the entire vascular circuit of any organ because of the enormity
of the vessels. The objective of the present study was to develop a novel method for the reconstruction of the full coronary
vascular tree from partial measurements. Our method includes the use of data on those parts of the tree that are measured
to extrapolate the data on those parts that are missing. Specifically, a two-step approach was employed in the reconstruction
of the entire coronary arterial tree down to the capillary level. Vessels > 40 μm were reconstructed from cast data while
vessels < 40 μm were reconstructed from histological data. The cast data were reconstructed one-bifurcation at a time while
histological data were reconstructed one-sub-tree at a time by “cutting” and “pasting” of data from measured to missing vessels.
The reconstruction algorithm yielded a full arterial tree down to the first capillary bifurcation with 1.9, 2.04 and 1.15
million vessel segments for the right coronary artery (RCA), left anterior descending (LAD) and left circumflex (LCx) trees,
respectively. The node-to-node connectivity along with the diameter and length of every vessel segment was determined. Once
the full tree was reconstructed, we automated the assignment of order numbers, according to the diameter-defined Strahler
system, to every vessel segment in the tree. Consequently, the diameters, lengths, number of vessels, segments-per-element
ratio, connectivity and longitudinal matrices were determined for every order number. The present model establishes a morphological
foundation for future analysis of blood flow in the coronary circulation. 相似文献
117.
R. G. McMurray T. K. Eubank A. C. Hackney 《European journal of applied physiology》1995,72(1-2):121-126
The effects of resistance exercise on the nocturnal responses of cortisol (CO), testosterone (TEST), human growth hormone (hGH), and thyroid hormones (T3, T4) were examined in eight trained weight lifters. Each subject completed two trials using a counterbalanced design: a control, no exercise trial (CON) and a heavy resistance exercise session of three sets of six exercises to exhaustion (RE). The exercise session took place between 1900 and 2000 hours. Blood was sampled prior to and at 20-min intervals after RE. For both trials blood was sampled at hourly intervals from 2100 hours until 0700 hours. The hGH and CO concentrations were increased up to 40-min post-exercise (P < 0.05), but returned to resting levels 1 h post-exercise. Nocturnal hGH concentration was not affected by RE (P > 0.26) and peaked at 0200 hours and declined until 0700 hours. Similarly, the CO responses were similar between the trails (P > 0.14). This CO concentrations declined from 2200 hours until 0100 hours, then increased steadily until 0700 hours. The TEST concentrations during both trials rose steadily from 2200 hours until 0700 hours; however, the rise in TEST from 0500–0700 hours during RE was greater than during the CON trails (P = 0.059). The T3 concentrations were unchanged by exercise and were similar at all times between trails. The T4 concentrations were elevated for 20 min after RE; however nocturnal T4 concentrations were lower after RE than during CON. These results would suggest that bGH and CO may have limited nocturnal reactivity to resistance exercise. However, the nocturnal alterations of TEST and T4 after resistance exercise, although small, may have implications for muscle anabolism. 相似文献
118.
Summary Five normal men performed seven sets of seven squats at a load equal to 80% of their seven repetition maximum. Plasma growth
hormone (GH) and lactate levels increased during and after the completion of the exercise. A significant (r=0.93, P<0.001) linear correlation was found between GH changes and the corresponding oxygen Demand/Availability (D/A) ratio expressed
by
(where f=[lactate at time x]/[lactate at time 0]). A retrospective examination of previously published data from our laboratory and others also demonstrated
the existence of a significant correlation between changes in plasma GH levels and the D/A ratios over a wide variety of exercise;
aerobic and anaerobic, continuous and intermittent, weight lifting and cycling, in both fit and unfit subjects under normoxic
and hypoxic conditions. It is suggested that the balance between oxygen demand and availability may be an important regulator
of GH secretion during exercise.
DCIEM No. 87-P-27 相似文献
119.
J. Caverzasio H. Murer H. Fleisch J. -P. Bonjour 《Pflügers Archiv : European journal of physiology》1982,394(3):217-221
Recent clearance studies have demonstrated that the maximal tubular reabsorption of inorganic phosphate (Pi) per ml of glomerular filtrate (max. TRPi/ml GF) of the whole kidney is markedly lower in adult than in young growing rats fed either normal (0.8 g%) or low (0.2 g%) phosphorus diet. In addition, in adult rats clearance studies indicate that enhancement of max. TRPi/ml GF is observed 21 days but not 8 days after starting the low (0.2%) phosphorus diet. In the present work we have studied in the same experimental condition the Na+-dependent Pi uptake in brush border membrane vesicles (BBMV) isolated from renal cortex of either young growing or adult rats. The results of this study indicate that under the low (0.2%) but not under the normal (0.8%) phosphorus diet the Na+-dependent Pi uptake by BBMV was significantly depressed in adult as compared to young growing rats. In adult rats the Pi transport response to Pi restriction monitored at the brush border membrane level was different from that observed by clearance studies in the whole kidney. Indeed, the Pi uptake by BBMV was already enhanced after 8 days of Pi restriction and it did not increase further when studied 21 days after starting the low (0.2%) phosphorus diet. These results suggest that the regulation of the overall transfer of Pi across the renal epithelium may involve other additional modulating factors than the Na+-dependent Pi transport system present in the luminal membrane of the proximal tubule. 相似文献
120.
新生儿血清瘦素水平变化与胰岛素和生长激素关系的研究 总被引:2,自引:0,他引:2
目的 探讨新生儿血清瘦素来源及其与胰岛素和生长激素的关系。方法 采用放射免疫法检测 80例新生儿静脉血和脐血瘦素水平 ,根据不同胎龄新生儿出生体重值分为大于胎龄儿 (LGA)组 2 8例 ,适于胎龄儿 (AGA)组 36例 ,小于胎龄儿 (SGA)组 16例 ;采用Rohrer′s指数 =出生体重 (g)× 10 0 /身长 (cm) 3 估测新生儿营养状态。结果 早产儿血清瘦素水平明显低于足月儿 (0 6 6± 1 0 3ng/mlvs 3 5 9± 2 16ng/ml,P <0 0 1) ;AGA儿血清瘦素水平 (3 0 6± 0 96ng/m1)明显低于LGA儿(4 0 3± 2 2 2ng/m1) ,而高于SGA儿 (1 13± 1 98ng/m1) ;足月新生儿血清瘦素水平与Rohrer′s指数、新生儿体重、胎龄 ,血清胰岛素、生长激素水平呈显著正相关。结论 新生儿体内瘦素主要来源于自身脂肪组织 ,它反映新生儿的生长营养状态 ,推测瘦素可能通过胰岛素、生长激素共同调节新生儿的生长发育 ,在胎儿和新生儿生长发育中起重要作用。 相似文献