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1.
Medical expulsion therapy has been shown to be a useful adjunct to observation in the management of ureteral stones. Alpha-1-adrenergic receptor antagonists have been studied in this role. Alpha-1 receptors are located in the human ureter, especially the distal ureter. Alpha-blockers have been demonstrated to increase expulsion rates of distal ureteral stones, decrease time to expulsion, and decrease need for analgesia during stone passage. Alpha-blockers promote stone passage in patients receiving shock wave lithotripsy, and may be able to relieve ureteral stent-related symptoms. In the appropriate clinical scenario, the use of alpha-blockers is recommended in the conservative management of distal ureteral stones.  相似文献   

2.
Kidney stones are a common problem for which inadequate prevention exists. We recruited ten recurrent kidney stone formers with documented calcium oxalate stones into a two phased study to assess safety and effectiveness of Cystone®, an herbal treatment for prevention of kidney stones. The first phase was a randomized double-blinded 12 week cross over study assessing the effect of Cystone® vs. placebo on urinary supersaturation. The second phase was an open label one year study of Cystone® to determine if renal stone burden decreased, as assessed by quantitative and subjective assessment of CT. Results revealed no statistically significant effect of Cystone® on urinary composition short (6 weeks) or long (52 weeks) term. Average renal stone burden increased rather than decreased on Cystone®. Therefore, this study does not support the efficacy of Cystone® to treat calcium oxalate stone formers. Future studies will be needed to assess effects on stone passage, or on other stone types.  相似文献   

3.
Roads with high traffic volumes are a source of animal mortality, can disrupt normal animal movements and dispersal, and may represent a potentially serious threat to wildlife population stability and viability. Retrofitting existing structures built for other purposes (e.g., drainage culverts or small below-grade access roads) to facilitate wildlife crossing by animals and to reduce mortality may be expensive if modifications to the existing structures themselves were involved. However, the environmental context surrounding these structures may influence the willingness of animals to cross, and management of some of these attributes may enhance the attractiveness of these structures. Culverts and underpasses are two common structures along roads in Portugal. We quantified the response of small and medium-sized carnivores to the presence of both types of existing passages by determining: (1) frequency of use; (2) whether use differed by type of passage, and if so; (3) by examining if associated environmental attributes might explain the differences observed. We surveyed 57 different passages along 252 km of highway with a total sampling effort of 2,330 passage trap-days. The mean passage rate for carnivores combined was 0.7 complete passages per crossing structure per day. Crossings by weasel, polecat, otter, and wildcat were infrequent or absent. Red fox, badger, genet and Egyptian mongoose used the crossing structures regularly and without obvious preference; stone marten preferred underpasses. Regression analyses showed the frequency of use by carnivores varied with structural, landscape, road-related features, and human disturbance with 17 of 26 (65%) attributes being significant. Larger passages with vegetation close to the passage entrances, favorable habitat in the surrounding area, and low disturbance by humans were important key features to regular use by the guild of species studied. Mitigation planning in areas with ecological significance for carnivores will be beneficial. Structural attributes and human disturbances are more difficult or expensive to change, even though related significantly to crossing use. Management of vegetation at passage entrances and restricting human use near passages in carnivore suitable areas may substantially improve crossing attractiveness for the guild of carnivore species.  相似文献   

4.
Children may treat an invisible entity as a live and thinking entity, known as an imaginary companion (IC). Some researchers suggest that this is simply pretend play, but it is possible that children experience agency in their interactions with ICs. Given the literature on cognitive science and social brain research, we hypothesize that young children may have an agent-perception system that responds to an invisible agent by which they may experience realistic agency in their interactions with ICs. In this study, children were introduced to an invisible agent and an invisible stone. However, they assigned biological and psychological properties to the agent but not the stone. The tendency of assigning such properties was stronger in children with ICs than in those without ICs. These results contribute to our understanding of cognitive and neural development in typical and atypical children.  相似文献   

5.
Low passage BHK 21/13 cells contain two cell surface enzymes, a nucleotide pyrophosphatase and a monophosphoester hydrolase, which together hydrolyze exogenous UDP-galactose to free galactose. During serial passage, BHK cells successively lose both enzymes. Concomitant with the loss of these enzymatic activities, changes in cell morphology, as well as in the serum requirement for the initiation of DNA synthesis, were observed. Clonal sublines of BHK cells were isolated, which differed qualitatively in their ability to hydrolyze UDP-galactose. Clonal BHK sublines, which exhibited both enzymatic activities on their cell surface, resembled low passage BHK cells in morphology and serum requirement for the initiation of DNA synthesis. Sublines not containing these enzymes resembled BHK cells of high passage cultures. The ability of intact BHK cells to hydrolyze exogenous nucleotide sugars may serve as an indicator for the progression of BHK cells from a normal to a more transformed state.  相似文献   

6.
This article interprets 'natural' features of the landscape unaltered by human agency – hills, rock outcrops, and solution basins – in West Penwith, Cornwall, and discusses their significance in relation to Neolithic, Bronze, and Iron Age monuments, cairns, and enclosures. We argue that 'nature' provides a fundamental conceptual resource for understanding cultural form, and that 'natural' architecture had a super-natural significance for prehistoric populations. Its meanings were intricately linked to elemental processes involving metaphorical relationships between water and fire, stone, sea, and the passage of the sun in the heavens.  相似文献   

7.
A retrospective study was conducted to assess the efficacy of D-penicillamine in the management of cystinuria, as well as to define the frequency and nature of untoward reactions to this drug. Fifty-six individuals were identified who, by stone analysis and/or biochemical studies, met the accepted diagnostic criteria for phenotypic cystinuria. The majority of these patients presented in the second decade of life with evidence of stone formation: renal colic, hematuria, and/or stone passage. Thirty-five individuals were considered to have clinically advanced cystinuria because they had required at least one urinary tract lithotomy. In these advanced cases, frequency of subsequent lithotomies and episodes of renal colic per 100 patient-years of observation were used as indices to measure the efficacy of D-penicillamine treatment. By both measurements, D-penicillamine significantly improved the clinical course of patients. The incidence of acute drug sensitivity reactions (rash, fever, and/or arthropathy) was in excess of 40 percent. Delayed drug-induced proteinuria occurred in 34 percent of treated patients. We conclude that D-penicillamine is useful in the treatment of cystinuria. Because of the significant number of untoward drug reactions, however, we believe the drug should be instituted only in selected, high-risk patients.  相似文献   

8.
Fishways have been developed to restore longitudinal connectivity in rivers. Despite their potential for aiding fish passage, fishways may represent a source of significant energetic expenditure for fish as they are highly turbulent environments. Nonetheless, our understanding of the physiological mechanisms underpinning fishway passage of fish is still limited. We examined swimming behaviour and activity of silver redhorse (Moxostoma anisurum) during its upriver spawning migration in a vertical slot fishway. We used an accelerometer-derived instantaneous activity metric (overall dynamic body acceleration) to estimate location-specific swimming activity. Silver redhorse demonstrated progressive increases in activity during upstream fishway passage. Moreover, location-specific passage duration decreased with an increasing number of passage attempts. Turning basins and the most upstream basin were found to delay fish passage. No relationship was found between basin-specific passage duration and activity and the respective values from previous basins. The results demonstrate that successful fishway passage requires periods of high activity. The resultant energetic expenditure may affect fitness, foraging behaviour and increase susceptibility to predation, compromising population sustainability. This study highlights the need to understand the physiological mechanisms underpinning fishway passage to improve future designs and interpretation of biological evaluations.  相似文献   

9.
Bearded capuchin monkeys crack nuts with naturally varying stone hammers, suggesting they may tune their grips and muscular forces to each stone. If so, they might use discrete actions on a stone before lifting and striking, and they would likely use these actions more frequently when the stone is larger and/or less familiar and/or when first initiating striking. We examined the behavior of (a) four monkeys (all proficient at cracking nuts) with two larger (1 kg) and two smaller (0.5 kg) stones, (b) 12 monkeys with one 1 kg stone, and (c) one monkey during its first 100 strikes with an initially unfamiliar 1 kg stone. Bearded capuchin monkeys used three discrete actions on the stone before striking, all more often with the larger stones than the smaller stones. We infer that the first discrete action (Spin) aided the monkey in determining where to grip the stone, the second (Flip) allowed it to position the stone on the anvil ergonomically before lifting it, and the third (Preparatory Lift) readied the monkey for the strenuous lifting action. The monkey that provided 100 strikes with one initially unfamiliar stone performed fewer Spins in later strikes but performed Flip and Preparatory Lift at consistent rates. The monkeys gripped the stone with both hands along the sides to lift it, but usually moved one or both hands to the top of the stone at the zenith of the lift for the downward strike. The findings highlight two new aspects of the capuchins’ nut‐cracking: (a) Anticipatory actions with the stone before striking, especially when the stone is larger or unfamiliar, and when initiating striking and (b) shifting grips on the stone during a strike. We invite researchers to investigate if other taxa use anticipatory actions and shift their grips during percussive activity.  相似文献   

10.
Efforts to reduce the negative impacts of roads on wildlife may be hindered if individuals within the population vary widely in their responses to roads and mitigation strategies ignore this variability. This knowledge is particularly important for medium-sized carnivores as they are vulnerable to road mortality, while also known to use available road passages (e.g., drainage culverts) for safely crossing highways. Our goal in this study was to assess whether this apparently contradictory pattern of high road-kill numbers associated with a regular use of road passages is attributable to the variation in behavioral responses toward the highway between individuals. We investigated the responses of seven radio-tracked stone martens (Martes foina) to a highway by measuring their utilization distribution, response turning angles and highway crossing patterns. We compared the observed responses to simulated movement parameterized by the observed space use and movement characteristics of each individual, but naïve to the presence of the highway. Our results suggested that martens demonstrate a diversity of responses to the highway, including attraction, indifference, or avoidance. Martens also varied in their highway crossing patterns, with some crossing repeatedly at the same location (often coincident with highway passages). We suspect that the response variability derives from the individual''s familiarity of the landscape, including their awareness of highway passage locations. Because of these variable yet potentially attributable responses, we support the use of exclusionary fencing to guide transient (e.g., dispersers) individuals to existing passages to reduce the road-kill risk.  相似文献   

11.
Augmented nuclease activity during cellular senescence in vitro   总被引:1,自引:0,他引:1  
The molecular correlates of the limited proliferative potential of normal human diploid fibroblasts and extensive single-strand breaks in the genomic DNA of these cells were examined by transfection analyses in which DNA replication could be uncoupled from DNA damage and repair. Both supercoiled (fmI), and restriction endonuclease-cleaved, linear (fmIII) molecules of a well-defined bacterial plasmid DNA, pBR322, were transfected into, and subsequently recovered from, early and late passage fibroblasts. Southern blot analysis revealed that fmI DNA was converted by random nicks into fmII DNA slightly more rapidly in late passage cells compared with cells at early passage. Similarly, fmII and fmIII DNAs also sustained multiple random nicks and no appreciable net religation of free ends of fmIII DNA could be detected at either passage. In addition, the efficiency of in vitro ligation of fmIII DNA recovered from late passage cells was also reduced, compared with that from early passage cells, as determined by Southern blotting. These data suggest that in the absence of DNA replication, a putative nuclease activity may contribute to DNA damage observed in senescent cells, which, in turn, may be causally related to their limited replicative potential.  相似文献   

12.
It has previously been shown that serum-deprived, early passage quiescent human diploid fibroblastlike (HDFL) cells are able to inhibit cycling cells from entry into DNA synthesis upon cell fusion. We have found that the degree of inhibition of DNA synthesis in the heterokaryon correlates with the duration of serum deprivation, which is consistent with the suggestion that serum-deprived cells may enter progressively deeper stages of G0 as they increase their time in quiescence. In contrast to fusions with senescent cells, in heterokaryons between serum-deprived early passage and cycling young cells transient inhibition of protein synthesis with cycloheximide or inhibition of RNA synthesis with 5–6-dichloro-1-β-D-ribofuranosyl benzimidazole (DRB) did not stimulate nuclear [3H]-thymidine incorporation. These results suggest that differences may exist in the mechanisms responsible for inhibiting cell cycle progression in senescent vs early passage quiescent HDFL cells.  相似文献   

13.
The pathogenesis of the fibrotic disease Dupuytren's contracture remains unclear. The disease process includes two structurally distinct fibrotic elements, the nodule and the cord. It has been proposed that as the disease progresses, nodules develop into cords. To corroborate that hypothesis, the authors took advantage of cultured fibroblast differences found between gap junction intercellular communication and fibroblast-populated collagen lattice contraction. Paired fibroblast cell lines of nodules and cords derived from four patients with Dupuytren's disease were maintained in culture for at least eight passages. The presence of gap junction intercellular communication in nodule- and cord-derived fibroblasts was documented and reported as a coupling index. The contraction of free-floating nodule- or cord-derived collagen lattices was also documented and reported. Early passage (passage 4) cord-derived fibroblasts showed a significant increase in coupling index compared with passage 4 nodule-derived fibroblasts (4.0 +/- 0.4 versus 2.5 +/- 0.3, respectively), where p < or = 0.01. However, late passage (passage 8) nodule- and cord-derived fibroblasts were equivalent in their coupling index (4.1 +/- 0.4 versus 4.4 +/- 0.4, respectively). Early passage nodule-derived fibroblast-populated collagen lattices contracted by 64 percent, whereas late passage nodule-derived lattices showed less contraction, at only 40 percent. Early and late passage cord-derived lattices contracted 46 and 37 percent, respectively. All nodule- and cord-derived cell lines were statistically equivalent at lattice contraction by passage 8. These in vitro studies support the hypothesis that fibroblasts derived from Dupuytren's contracture nodules change their phenotype after undergoing repeated cell passage, acquiring a cord-like fibroblast phenotype. Dupuytren's nodules represent the early, active form of fibrosis in which cells are more proliferative, better at fibroblast-populated collagen lattice contraction, and display less gap junction intercellular communication. The speculation is that alterations in gap junction intercellular communication may be involved in the progression of Dupuytren's nodules to cords as the disease progresses.  相似文献   

14.
Movement plays a role in structuring the interactions between individuals, their environment, and other species. Although movement models coupled with empirical data are widely used to study animal distribution, they have seldom been used to study search time. This paper proposes first passage time as a novel approach for understanding the effect of the landscape on animal movement and search time. In the context of animal movement, first passage time is the time taken for an animal to reach a specified site for the first time. We synthesize current first passage time theory and derive a general first passage time equation for animal movement. This equation is related to the Fokker–Planck equation, which is used to describe the distribution of animals in the landscape. We illustrate the first passage time method by analyzing the effect of territorial behavior on the time required for a red fox to locate prey throughout its home range. Using first passage time to compute search times, we consider the effect of two different searching modes on a functional response. We show that random searching leads to a Holling type III functional response. First passage time analysis provides a new tool for studying how animal movement may influence ecological processes.  相似文献   

15.
Wild bearded capuchin monkeys (Sapajus libidinosus) habitually use stone hammers to crack open palm nuts and seeds on anvils. This activity requires strength, balance, and precise movement of a large stone with respect to the item placed on an anvil. We explored how well young monkeys cope with these challenges by examining their behavior and the behavior of adults while they cracked palm nuts using a stone. Using video records, we compared actions of six juvenile (2–5 years) and six adult (7+ years) wild monkeys during their first 20 strikes with one unfamiliar ellipsoid, quartzite stone (540 g), and the outcomes of these strikes. Compared with adults, juveniles cracked fewer nuts, performed a more diverse set of exploratory actions, and less frequently placed one or both hands on top of the stone on the downward motion. Adults and juveniles displayed similar low frequencies of striking with a slanted trajectory, missing the nut, and losing control over the nut or stone after striking. These findings indicate that young monkeys control the trajectory of a stone adequately but that is not sufficient to crack nuts as effectively as adults do. Compared with juveniles, adults more quickly perceive how to grip the stone efficiently, and they are able to adjust their grip dynamically during the strike. Young monkeys develop expertise in the latter aspects of cracking nuts over the course of several years of regular practice, indicating that perceptual learning about these aspects of percussion occurs slowly. Juvenile and adult humans learning to use stones to crack nuts also master these features of cracking nuts very slowly.  相似文献   

16.
Archeologists have long assumed that earlier hominins were obligatory stone tool users. This assumption is deeply embedded in traditional ways of describing the lithic record. This paper argues that lithic evidence dating before 1.7 Ma reflects occasional stone tool use, much like that practiced by nonhuman primates except that it involved flaked‐stone cutting tools. Evidence younger than 0.3 Ma is more congruent with obligatory stone tool use, like that among recent humans. The onset of habitual stone tool use at about 1.7 Ma appears correlated with increased hominin logistical mobility (carrying things). The onset of obligatory stone tool use after 0.3 Ma may be linked to the evolution of spoken language. Viewing the lithic evidence dating between 0.3‐1.7 Ma as habitual stone tool use explains previously inexplicable aspects of the Early‐Middle Pleistocene lithic record.  相似文献   

17.
A selective replicative pressure occurs during the evolution of simian virus 40 variants. When the replication origin is duplicated as an inverted repeat, there is a dramatic enhancement of replication. Having regulatory sequences located between the inverted repeat of ori magnifies their enhancing effect on replication. A passage 20 variant and a passage 45 variant containing three pairs of an inverted repeat of ori replicated more efficiently than a passage 13 variant containing nine copies of ori arranged in tandem. A 69-base-pair cellular sequence inserted between inverted repeats of ori of both passage 40 and 45 variants enhanced simian virus 40 DNA replication. Differences in replication efficiencies became greater as the total number of replicating species was increased in the transfection mixture, under conditions where T antigen is limiting. In a competitive environment, sequences flanking the replication origin may be inhibitory to replication.  相似文献   

18.
Immediate steps in the treatment of ureteral stone, beginning with the often acute onset, are relief of pain, urinalysis (including Gram stain), forcing fluids, examination of urine for the stone and urography at the earliest feasible time. If the stone causes continual pain or appears unlikely to be passed safely, it should be removed—with a cystoscope if possible; if not, by operation which may be done while the patient is still under anesthesia.To combat further stone formation a large fluid intake should be maintained, the extracted stone analyzed, an acid ash diet prescribed, serum calcium and phosphorus measured, urinary stasis corrected and urinary infection and distant foci of infection cured. Vitamin A, aluminum gels and particularly hyaluronidase appear promising as preventives to stone formation.  相似文献   

19.
Data are provided on the development of tumorigenicity in cells of 6 independently produced lines of mouse and rat embryonic fibroblasts during their prolonged passage in vitro. The data on the development of lysis of these cells by macrophages and activated lymphocytes during the same passage indicate that enhanced cell lysis of cells by natural effectors and, hence, cell recognition by them may be regarded as an obligatory manifestation of cell malignization.  相似文献   

20.
目的:探讨通道大小对经皮肾镜取石患者围手术期出血的影响及治疗策略。方法:回顾性分析2016年1月至2017年1月在我院行F24和F18通道的经皮肾镜取石术的189例患者临床资料,分别比较具有不同临床特征患者围手术期出血的发生情况。结果:95例F24通道患者平均出血量为125±19.6 m L,其中5人进行输血治疗;94例F18通道患者平均出血量为103±17.6m L,其中3人进行输血治疗。F18通道经皮肾镜取石术的出血组和非出血组糖尿病、高血压的发生率、结石表面积、通道数量、手术时间比较差异均具有统计学意义(P0.05)。F24通道经皮肾镜取石术的出血组和非出血组孤立肾、高血压发生率、结石面积、肾实质厚度、通道数量和手术时间比较差异均具有统计学意义(P0.05)。F18通道经皮肾镜取石围手术期出血量显著少于F24通道(P0.05)。结论:孤立肾、高血压、结石面积大、肾实质厚、肾积水轻、通道数量多和手术时间长均会导致经皮肾镜围手术期出血几率和出血量增加,并且F24通道相较于F18通道出血量更多。  相似文献   

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