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141.
Adrenomedullin stimulates the growth of cultured normal human osteoblasts as an autocrine/paracine regulator 总被引:2,自引:0,他引:2
Adrenomedullin (AM) is a 52 amino acid peptide that is synthesized in a variety of tissues, including the vessels and bones. This study showed that normal human osteoblast (NHOst) secreted immunoreactive AM and that AM stimulated intracellular cAMP production in these cells. An anti-AM monoclonal antibody, which inhibited endogenous AM, caused the number of NHOst to decrease. The effect of a low concentration AM was inhibited by addition of a cAMP-dependent protein kinase A inhibitor (H89). These data suggest that AM is an autocrine or paracrine regulator that promotes the proliferation of NHOst via the cAMP pathway. 相似文献
142.
Kimura K Tsuda K Moriwaki C Kawabe T Hamada M Obana M Baba A Hano T Nishio I 《Biochemical and biophysical research communications》2002,294(2):359-362
Leukemia inhibitory factor (LIF) is a cytokine, which inhibits angiogenesis and decreases endothelial cell proliferation and migration, suggesting that LIF may modulate vascular tone. In this study, we examined the effects of LIF on the tone of rat arteries. The isometric tension of ring preparations from rat superior mesenteric arteries was continuously measured. LIF relaxed the mesenteric arteries in a dose-dependent manner, when the arterial rings were precontracted with phenylephrine. The relaxation was totally inhibited by mechanical removal of endothelium. N(G)-nitro-L-arginine methyl ester did not affect the relaxation by LIF. Ca(2+)-dependent K channel (KCa) blockers, apamin with charybdotoxin, inhibited the relaxation by LIF. Catalase, an enzyme which scavenges hydrogen peroxide, also inhibited the relaxation by LIF. Endothelium-derived hyperpolarizing factor relaxes smooth muscle cells and the effect is blocked by KCa and catalase. Our results suggest that LIF regulates vascular tone through the effect of this factor. 相似文献
143.
Yeast cells exhibit sustained ultradian oscillations of energy metabolism in coupling with cell cycle and stress resistance oscillations in continuous culture. We have reported that the rhythmic expression of Gts1p is important for the maintenance of ultradian rhythms. Structurally, Gts1p contains sequence motifs similar to N-degron and the ubiquitin association domain, raising the possibility that the Gts1p level is regulated by degradation via ubiquitination. When the lysine residue at the putative ubiquitination site of the N-degron was substituted with arginine, both the protein level and half-life of mutant Gts1p increased. During continuous culture, the protein level of the mutant Gts1p was elevated and did not fluctuate, leading to the disappearance of metabolic oscillation within a day. Furthermore, using three Gts1ps containing mutations in the ubiquitin association domain, we showed that the lower the binding activity of the mutant Gts1ps for polyubiquitin in vitro, the higher the protein level in vivo. Expression of the mutant Gts1ps in the continuous culture resulted in an increase in Gts1p and early loss of the oscillation. Therefore, Gts1p is degraded through conjugation with ubiquitin, and the UBA domain promoted the degradation of ubiquitinated Gts1p, causing a fluctuation in protein level, which is required for the maintenance of metabolic oscillations. 相似文献
144.
Vertebrate genomes are mosaics of isochores. On the assumption that marked differences exist in the isochore structure between warm-blooded and cold-blooded animals, variations among vertebrates were previously attributed to adaptation to homeothermy. However, based on the data of coding regions from representatives of extant vertebrates, including a turtle, a crocodile (Archosauromorpha) and a few kinds of snakes (Lepidosauromorpha), it was recently hypothesized that the common ancestors of mammals, birds and extant reptiles already had the "warm-blooded" isochore structure. To test this hypothesis, the nucleotide sequences of alpha-globin genes including non-coding regions (introns) from two snakes, N. kaouthia and E. climacophora, were determined (accession number: AB104824, AB104825). The correlation between the GC contents in the introns and exons of alpha-globin genes from snakes and those from other vertebrates supports the above hypothesis. Similar analysis using data for exons and introns of other genes obtained from the GenBank (Release 131) also support the above hypothesis. 相似文献
145.
Detailed zooplankton records from a 26-cm sediment core with a time resolution of approximately 3–10 years were obtained from Lake Biwa, Japan, to examine the historical variations in the zooplankton community during the 20th century. In the sediments, selected zooplankton remains have fluctuated over the years. Daphnia – large zooplankton herbivores – did not occur from 1900 to 1920, and formed a very minor component of the zooplankton community in the following 30 years, while Bosmina – small zooplankton herbivores – were common during this period. In the mid-1960s, however, when eutrophication was noticeable in this lake, Daphnia numbers increased dramatically and became the dominant zooplankton thereafter. In contrast, Difflugia brevicolla and D. biwae, two amoeboid protozoans that live in connection with the lake bottom environment, occurred abundantly until the late 1950s, but gradually decreased after the mid-1960s. In particular, D. biwae, a species peculiar to this lake, was not found in sediment dated after 1980, suggesting its extinction. These results indicate that the zooplankton community structure changed greatly in the 1960s, and suggest that the eutrophication occurring at this time altered the relative strength of top-down and bottom-up forces on the zooplankton community in Lake Biwa. 相似文献
146.
147.
Anthropometric measurements of the endoscopic eyebrow lift in the treatment of facial paralysis 总被引:2,自引:0,他引:2
Endoscopic eyebrow lift was performed on 51 patients presenting with eyebrow ptosis due to facial paralysis. The resulting anthropometric measurements of eyebrow position were analyzed statistically to evaluate the effectiveness of this method. When preoperative eyebrow differences between the paralyzed and nonparalyzed sides were measured, the average difference at midpoint was 4.4 mm, and at the highest point, 4.6 mm. When the same points were measured postoperatively, the average difference at midpoint was 2.4 mm, and at the highest point, 2.3 mm. The difference in eyebrow height between the paralyzed and nonparalyzed sides correlated positively with age, both preoperatively and postoperatively. However, differences between preoperative and postoperative eyebrow height (which reflects the effectiveness of endoscopic eyebrow lift) at the highest point did not correlate with age and at the midpoint displayed a slightly negative correlation with age. These results suggest that endoscopic eyebrow lift is effective among young patients whose eyebrow ptosis is minor and is relatively ineffective among elderly patients whose eyebrow ptosis is severe. The conventional method of juxta-brow excision is indicated for elderly patients, for whom the operative scar is almost inconspicuous. 相似文献
148.
Skeletal maturation in the chimpanzee hand and wrist (the RUS system; radius, ulna, and short bones) was studied both longitudinally
and cross-sectionally. Maturity states were evaluated in each of the 13 bones of the RUS system based on the TW2 method (Tanner
and Whitehouse method), and the RUS score was calculated by the summation of scores for these bones. Individual variation
was examined by means of residual curves and pseudo-velocity curves of RUS score and anterior trunk length (ATL). Norms of
the age change pattern in RUS skeletal maturation and the growth of ATL were determined for each sex, and the relationships
among ATL growth and skeletal and reproductive maturation were examined. We found a fairly good relationship between ATL growth
and RUS skeletal maturation. Comparison of growth and development between humans and chimpanzees showed that growth characteristics
are coupled with each other at puberty in male chimpanzees and in both sexes of humans. Although nutritional condition influenced
ATL growth in infancy, it had no effect on the RUS maturational process. Social relationships appeared to influence both ATL
growth and RUS maturation. Analyses on relationships between RUS skeletal maturation, ATL growth, and reproductive maturation,
showed that RUS skeletal maturation is a good indicator of "physiological age". 相似文献
149.
Gunji H Hosaka K Huffman MA Kawanaka K Matsumoto-Oda A Hamada Y Nishida T 《Primates; journal of primatology》2003,44(2):145-149
We examined bone mineral density (BMD) of the femoral neck and lumbar vertebrae of four chimpanzee skeletons from Mahale Mountains
National Park, Tanzania, and four captive ones, with a dual energy X-ray absorptiometer. The BMD of Wansombo, an old female
chimpanzee from Mahale , was remarkably lower than the mean of the other six younger adult female chimpanzees and categorized
as osteoporosis. Posture, locomotion, and trunk-sacral anatomy of chimpanzees may have prevented fractures in Wansombo, whose
BMD was below human osteoporosis criteria.
Electronic Publication 相似文献
150.
Multiform biosynthetic pathway of syringyl lignin in angiosperms 总被引:6,自引:0,他引:6
To clarify the pathway for biosynthesis of sinapyl alcohol in angiosperms, tracer experiments using stable isotopes were performed on robinia ( Robinia pseudoacacia L.), oleander ( Nerium indicum Mill.), magnolia ( Magnolia kobus DC.) and Arabidopsis thaliana (L.) Heynh. Precursors used in the experiment were (13)C- and (2)H ( D)-labeled [8-(13)C, 3-OCD(3)]ferulic acid and [8-(13)C, 3,5-OCD(3)]sinapic acid. The incorporation of labeled precursor into lignin was confirmed by gas chromatography-mass spectrometry of the products of derivatization followed by reductive cleavage. Crude extracts of differentiating xylem or stems from these plants were also assayed for 4-coumarate-CoA ligase (4CL; EC 6.2.1.12) activity using sinapic acid and ferulic acid as substrates. In robinia and oleander, 4CL activity toward sinapic acid was detected, and labeled sinapic acids were incorporated into syringyl lignin. These results indicate that robinia and oleander have a pathway that produces sinapyl alcohol from sinapic acid via sinapoyl-CoA. By contrast, in magnolia and Arabidopsis, 4CL activity toward sinapic acid could not be detected, and labeled sinapic acid was not incorporated into lignin. These results suggest that syringyl lignin biosynthesis in angiosperms operates via multiple pathways that depend on the species. 相似文献