共查询到20条相似文献,搜索用时 14 毫秒
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Recent findings of thromboplastin (TRPL) investigations are presented in a brief survey. After enumerating the possibilities of separating this lipoprotein into two shares, the chemical characterization of protein and lipid fraction is represented, the possibilities and conditions of recombining both shares are mentioned and the effectiveness of TRPL in the exogenous coagulation system is illustrated. Furthermore, the liberation of TRPL by leukocytes is referred to and feasible mechanisms of this liberation are discussed. Finally the relations of TRPL to tumour cell materials promoting coagulation and from amnion liquid are discussed. 相似文献
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The field of single-cell sequencing is fleetly expanding, and many techniques have been developed in the past decade. With this technology, biologists can study not only the heterogeneity between two adjacent cells in the same tissue or organ, but also the evolutionary relationships and degenerative processes in a single cell. Calling variants is the main purpose in analyzing single cell sequencing (SCS) data. Currently, some popular methods used for bulk-cell-sequencing data analysis are tailored directly to be applied in dealing with SCS data. However, SCS requires an extra step of genome amplification to accumulate enough quantity for satisfying sequencing needs. The amplification yields large biases and thus raises challenge for using the bulk-cell-sequencing methods. In order to provide guidance for the development of specialized analyzed methods as well as using currently developed tools for SNS, this paper aims to bridge the gap. In this paper, we firstly introduced two popular genome amplification methods and compared their capabilities. Then we introduced a few popular models for calling single-nucleotide polymorphisms and copy-number variations. Finally, break-through applications of SNS were summarized to demonstrate its potential in researching cell evolution. 相似文献
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M A Visconti G C Ramanzini C R Camargo A M Castrucci 《The Journal of experimental zoology》1999,284(5):485-491
Skins of Potamotrygon reticulatus are light in color in vitro, exhibiting punctate melanophores. Alpha-Melanocyte stimulating hormone (EC(50) = 4.58 x 10(-9) M) and prolactin (EC(50) = 1.44 x 10(-9) M) darken the skins in a dose-dependent manner. The endothelins ET-1, ET-2 and ET-3, and the purines, ATP, and uracil triphosphate (UTP) were not able to induce either skin lightening or darkening. Forskolin and the calcium ionophore A23187 promoted a dose-dependent darkening response, whereas N(2), 2'-O-dibutyryl guanosine 3'-5'-cyclic monophosphate (db cyclic GMP), phorbol-12-myristate-13-acetate (TPA), and 1-oleoyl-2-acetyl-sn-glycerol (OAG) were ineffective. The maximal response obtained with the calcium ionophore A23187 was only 76% of maximal darkening. These results indicate that the cyclic adenosine 3'-5'-monophosphate (cAMP) pathway is probably involved in the pigment dispersion of P. reticulatus melanophores. Other experiments should be done to further investigate how cytosolic calcium may be physiologically increased, and the existence of a putative cross-talk between calcium and cAMP signals. In conclusion, the only hormones effective on P. reticulatus melanophores were prolactin and alpha-MSH. No aggregating agent has been shown to antagonize these actions. Prolactin effect on elasmobranch melanophores adds a novel physiological role to this ancient hormone. J. Exp. Zool. 284:485-491, 1999. 相似文献
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Nectar biodiversity: a short review 总被引:9,自引:0,他引:9
Nectaries differ in many aspects but a common feature is some kind of advantage for the plant conferred by foraging of consumers
which may defend the plant from predators in the case of extrafloral nectaries, or be agents of pollination in the case of
floral nectaries. This minireview is concerned mainly with floral nectaries and examines the following characteristics: position
in flower; nectary structure; origin of carbohydrates, aminoacids and proteins; manner of exposure of nectar; site of nectar
presentation; volume and production of nectar in time; sexual expression of flower and nectary morphology; nectar composition
and floral sexual expression; variability of nectar composition; fate of nectar; energy cost of nectar production. The species
of certain large families, such as Brassicaceae, Lamiaceae and Asteraceae, resemble each other in nectary organisation; other
families, such as Cucurbitaceae and Ranunculaceae, have various types of organisation. A scheme is presented to illustrate
factors influencing nectary and nectar biodiversity.
Received July 23, 2002; accepted September 18, 2002
Published online: June 2, 2003 相似文献
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Introduction
The epidemiology and antibiotic resistance of Staphylococcus aureus have evolved, underscoring the need for novel antibiotics, particularly against methicillin-resistant S. aureus (MRSA). Telavancin is a bactericidal lipoglycopeptide with potent activity against Gram-positive pathogens.Objective
To systematically review and synthesize the available evidence from randomized controlled trials (RCTs) evaluating telavancin in the treatment of patients with infections due to Gram-positive organisms with the methodology of meta-analysis.Results
Six RCTs comparing telavancin with vancomycin were included; 4 (2229 patients) referred to complicated skin and soft tissue infections (cSSTIs) and 2 (1503 patients) to hospital-acquired pneumonia (HAP). Regarding cSSTIs, telavancin and vancomycin showed comparable efficacy in clinically evaluable patients (odds ratio [OR] = 1.10 [95% confidence intervals: 0.82–1.48]). Among patients with MRSA infection, telavancin showed higher eradication rates (OR = 1.71 [1.08–2.70]) and a trend towards better clinical response (OR = 1.55 [0.93–2.58]). Regarding HAP, telavancin was non-inferior to vancomycin in terms of clinical response in two Phase III RCTs; mortality rates for the pooled trials were comparable with telavancin (20%) and vancomycin (18.6%). Pooled data from cSSTIs and HAP studies on telavancin 10 mg/kg indicated higher rates of serum creatinine increases (OR = 2.22 [1.38–3.57]), serious adverse events (OR = 1.53 [1.05–2.24]), and adverse event-related withdrawals (OR = 1.49 [1.14–1.95]) among telavancin recipients.Conclusion
Telavancin might be an alternative to vancomycin in cases of difficult-to-treat MRSA infections. The potent antistaphylococcal activity of telavancin should be weighted against the potential for nephrotoxicity. 相似文献8.
Younes A 《Current molecular medicine》2005,5(7):609-613
It is now well established that the growth of primary and metastatic tumors is associated with the formation of new blood vessels, and that the growth of these tumor cells is frequently dependent on this neovasculature. The observation that inhibition of tumor angiogenesis in mice can lead to tumor regression or dormancy generated high level of enthusiasm and interest in developing new treatment strategies for human cancer based on inhibiting tumor angiogenesis. This short review focuses on recent advances in angiogenesis-research in non-Hodgkin's lymphoma and Hodgkin's disease. 相似文献
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Consumers are demanding foods that are "natural", of good nutritional and sensory quality, free from chemical preservatives, microbiologically safe and with extended shelf-life. High pressure processing can, potentially, meet these criteria. Recent advances in equipment design now allow foods to be processed up to 900 MegaPascals (130,000 psi). However, further work is required to more fully understand the factors that can affect the response of microorganisms, including pathogens, to pressure so that treatments can be optimised and microbiological safety can be assured. This paper describes how the pressure resistance of microorganisms can vary depending on factors such as species, strain, stage of growth and food composition. Strategies for overcoming the problem of pressure resistance will be discussed, for example the use of pressure cycling and the combination of pressure with mild heat. The current commercial uses of high pressure to preserve foods will be reported and potential applications will also be discussed. 相似文献
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It is known that soil is a recipient of solid wastes able to contain enteric pathogens in high concentrations. Although the
role of soil as a reservoir of certain bacterial pathogens is not in question, recent findings show that soil may have a larger
role in the transmission of enteric diseases than previously thought. Many of the diseases caused by agents from soil have
been well characterized, although enteric diseases and their link to soil have not been so well studied. Gastrointestinal
infections are the most common diseases caused by enteric bacteria. Some examples are salmonellosis (Salmonella sp.), cholera (Vibrio cholerae), dysentery (Shigella sp.) and other infections caused by Campylobacter jejuni, Yersinia sp. and Escherichia coli O157:H7 and many other strains. Viruses are the most hazardous and have some of the lowest infectious doses of any of the
enteric pathogens. Hepatitis A, hepatitis E, enteric adenoviruses, poliovirus types 1 and 2, multiple strains of echoviruses
and coxsackievirus are enteric viruses associated with human wastewater. Among the most commonly detected protozoa in sewage
are Entamoeba histolytica, Giardia intestinalis and Cryptosporidium parvum. This article reviews the existing literature of more than two decades on waste disposal practices that favor the entry of
enteric pathogens to soil and the possible consequent role of the soil as a vector and reservoir of enteric pathogens.
Electronic Publication 相似文献
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O I Karpov 《Antibiotiki i khimioterapii͡a》1999,44(10):28-32
A randomized study of a 3-day course of azithromycin therapy (500 mg once daily) vs. a 10-day course of co-amoxiclav therapy (625 mg thrice daily) in patients with acute sinusitis was performed with an account of the GCP criteria. One hundred patients in 2 groups each of 50 persons were enrolled. The estimates of the patient body temperature, headache, pain on palpation in the area of the accessory nasal sinuses, nasal cavity stuffing, nasal discharge nature and the nose mucous membrane appearance were recorded prior to the treatment, in 72 hours and on the 10th-12th and 26th-30th days of the treatment. The microbiological analysis of the punctate from the accessory nasal sinuses was undertaken before the antibiotic therapy and 72 hours after its start. The economic analysis included the cost of the antibiotic therapy course, hospitalization term, medical manipulations and laboratory tests as well as the cost/efficacy index. The frequency of the relapses within 6 months after the cure was estimated in the two groups compared. In 72 hours and on the 10th-12th days after the treatment start the efficacy of azithromycin was significantly higher than that of co-amoxiclav. The cure was stated in 41 (82 per cent) and 26 (52 per cent) patients on the 10th-12th days, in 6 (12 per cent) and 21 (42 per cent) patients the improvement was stated and the fail was stated in 3 (6 per cent) and 2 (4 per cent) patients respectively. The efficacy of the drugs on the 26th-30th days after the treatment start did not differ. The isolates of Staphylococcus aureus and Streptococcus pyogenes were the main pathogens. The bacteriologic eradication was recorded in 29 (90.6 per cent) patients treated with azithromycin and only in 18 (69.2 per cent) patients treated with co-amoxiclav. Adverse reactions and relapses of the disease within 6 months after the cure were more frequent in the patients treated with co-amoxiclav. The cost of the azithromycin therapy was significantly lower. It was shown that the shortened course of the azithromycin therapy provided earlier cure of the patients with acute sinusitis, better tolerance of the drug, less frequent adverse reactions, lower cost as compared to the use of co-amoxiclav and no relapses. 相似文献
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Multiple biological activities of curcumin: a short review 总被引:33,自引:0,他引:33
Turmeric (Curcuma longa rhizomes), commonly used as a spice is well documented for its medicinal properties in Indian and Chinese systems of medicine. It has been widely used for the treatment of several diseases. Epidemiological observations, though inconclusive, are suggestive that turmeric consumption may reduce the risk of some form of cancers and render other protective biological effects in humans. These biological effects of turmeric have been attributed to its constituent curcumin that has been widely studied for its anti-inflammatory, anti-angiogenic, anti-oxidant, wound healing and anti-cancer effects. As a result of extensive epidemiological, clinical, and animal studies several molecular mechanisms are emerging that elucidate multiple biological effects of curcumin. This review summarizes the most interesting in vitro and in vivo studies on the biological effects of curcumin. 相似文献
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《Comptes Rendus Palevol》2008,7(8):591-599
The fossil record of northwestern African carnivores is very patchy. The richest assemblage is that of the Late Pliocene of Ahl al Oughlam, with more than 20 species belonging to the main modern families. Some additions to its study are made here. The rather poor Early Pleistocene faunas are mainly marked by the arrival of a large Canis. A fauna of modern type, with example, the duo Hyaena–Crocuta, settles in the Earliest Pleistocene site of Tighenif, where some older elements linger on (Homotherium), beside some taxa of doubtful affinities, like a large Panthera, and a strange canid close to Nyctereutes, dominant at this site as well as at the slightly younger ones of Thomas and Oulad Hamida Quarries in Casablanca. All these faunas consist mostly of African taxa, together with a Palaearctic component whose importance increases towards the end of the Pleistocene. 相似文献
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Folic acid (FA) is an electroactive compound of biological origin. It helps our body to produce and maintain healthy cells. It can significantly reduce the occurrence of neural tube defects and also prevents change in DNA structure. FA deficiency can lead to various health risks. Therefore, a sensitive, specific, and reproducible way of FA detection is essential. A number of analytical methods are in practice for the quantification of FA. However, electroanalytical methods are attracting much attention because of their advantage over conventional methods, as they are fast, simple, sensitive, and cost effective. Moreover, modification of electrodes offers control over size and morphology which allows miniaturization for applicability in portable electrochemical devices. 相似文献
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Even though the molecular mechanisms underlying the Down syndrome (DS) phenotypes remain obscure, the characterization of the genes and conserved non-genic sequences of HSA21 together with large-scale gene expression studies in DS tissues are enhancing our understanding of this complex disorder. Also, mouse models of DS provide invaluable tools to correlate genes or chromosome segments to specific phenotypes. Here we discuss the possible contribution of HSA21 genes to DS and data from global gene expression studies of trisomic samples. 相似文献
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Amrita Kumari Panda Satpal Singh Bisht Surajit DeMondal N. Senthil Kumar G. Gurusubramanian Ashok Kumar Panigrahi 《Antonie van Leeuwenhoek》2014,105(4):623-639
The significance of Brevibacillus has been documented scientifically in the published literature and commercially in heterologous recombinant protein catalogs. Brevibacillus is one of the most widespread genera of Gram-positive bacteria, recorded from the diverse environmental habitats. The high growth rate, better transformation efficiency by electroporation, availability of shuttle vectors, production of negligible amount of extracellular protease, and the constitutive expression of heterologous proteins make some strains of this genus excellent laboratory models. Regarding biotechnological applications, this genus continues to be a source of various enzymes of great biotechnological interest due to their ability to biodegrade low density polyethylene, ability to act as a candidate bio-control agent, and more recently acknowledged as a tool for the overexpression. This article reviews the properties of Brevibacillus spp. as better biological tools with varied applications. 相似文献
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《Journal of Physiology》1997,91(3-5):151-171
Capsaicin, the pungent principle of hot pepper, because of its ability to excite and later defunctionalize a subset of primary afferent neurons, has been extensively used as a probe to elucidate the function of these sensory neurons in a number of physiological processes. In the rat stomach, experimental data provided clear evidence that capsaicin-sensitive (CS) sensory nerves are involved in a local defense mechanism against gastric ulcer. Stimulation of CS sensory nerves with low intragastric concentrations of capsaicin protected the rat gastric mucosa against injury produced by different ulcerogenic agents. High local desensitizing concentrations of capsaicin or systemic neurotoxic doses of the agent markedly enhanced the susceptibility of the rat gastric mucosa to later noxious challenge. Resiniferatoxin, a potent analogue of capsaicin possesses an acute gastroprotective effect similar to that of capsaicin in the stomach. The gastroprotective effect of capsaicin-type agents involves an enhancement of the microcirculation effected through the release of mediator peptides from the sensory nerve terminals with calcitonin gene-related peptide being the most likely candidate implicated. They do not depend on vagal efferent or sympathetic neurons or involve prostanoids. The gastric mucosal protective effect of prostacyclin is retained after systemic or topical capsaicin desensitization. Capsaicin-sensitive fibers are involved in the repair mechanisms of the gastric mucosa. A protective role for CS sensory nerves has also been demonstrated in the colon. In most studies, capsaicin given into the stomach of rats or cats inhibited gastric acid secretion. In humans, although recent studies provide evidence in favor of a beneficial effect of capsaicin on the gastric mucosa, an exact concentration-related assessment of the effect of the agent is still lacking. 相似文献