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乙型肝炎病毒基因组前-X区的分子流行病学研究   总被引:9,自引:4,他引:5  
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Glucose concentration in the amniotic fluid decreases towards the end of gestation, whereas the insulin concentration increases. The ratio between fetal (amniotic fluid) glucose to maternal glucose is reduced by about 50% at the end of pregnancy, whereas the ratio of C peptide is increased four times. The higher glucose concentration in amniotic fluid in early pregnancy could be explained by a lower fetal metabolic rate in the early stage of development and a low insulin activity of the fetus.  相似文献   

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Janikova M  Skarda J 《Neoplasma》2012,59(1):6-17
Cancer stem cells (CSCs) share many features with embryonic stem cells (ESCs) such as the ability for self-renewal and differentiation. Signaling pathways that are involved in these processes are also involved in chemo- and radioresistance (e.g. Wnt, Notch and Hedgehog pathways). This review is focused on the influence of three important differentiation pathways on carcinogenesis and on chemo- and radioresistance in ESCs and CSCs.  相似文献   

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W S Ruddell  L M Blendis    C L Walters 《Gut》1977,18(1):73-77
The concentrations of nitrite and thiocyanate in fasting and pentagastrin stimulated gastric juice and in saliva have been examined. Nitrite was found in all of 17 samples of fasting gastric juice, mean 4-9 +/- 1-1 muM. Stimulation of gastric secretion with pentagastrin caused no significant change in nitrite concentration. Thiocyanate was detected in all of 21 samples of fasting gastric juice and the difference in concentration between smokers and non-smokers probably reflects similar differences in saliva. In contrast to the nitrite data there was a significant drop in thiocyanate concentration of gastric juice after pentagastrin from 0-9 +/- 0-1 mM to 0-3 +/- 0-04 mM, suggesting a salivary origin for the thiocyanate in gastric juice. Thiocyanate is a powerful catalyst of nitrosation, which, together with small amounts of nitrite and naturally occurring amines could lead to the intragastric formation of carcinogenic nitrosamines and in certain circumstances be a factor in the aetiology of gastric cancer.  相似文献   

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As the increase in lifespan brings to light diseases that were previously not clinically detectable, osteoporosis has become an issue of worldwide significance. The disease is marked by a loss of bone mass; the bones become less dense, fragile and more prone to fracturing. Because it is regulated by endocrine and environmental factors, osteoporosis presents a multifactorial etiopathogenesis, with the genetic component accounting for 70% of an individual variation in bone mass density (BMD), the principal determinant, with age, of fracture risk. Pathological conditions such as celiac disease (CD) exacerbate the process of bone loss, so that the occurrence of osteoporosis in celiac subjects is of particular note: indeed, the screening of osteoporosis patients for this disease is advisable, since it may be the only sign of undiagnosed CD. An increase in interleukin IL-1β, of the IL-1 system, in the relatives of celiac patients confirms the genetic predisposition to osteoporosis and its presence is evidence of an association between the two conditions. The direct effect on the bones of CD is secondary to poor absorption of calcium and vitamin D. In women osteoporosis is indirectly associated with early menopause and amenorrhea, and it may follow prolonged breast-feeding and frequent pregnancies, while in men it is associated with hypogonadism and GH deficit. These endocrine and non-endocrine factors exert their effects on bones by modulating the RANK/RANK-L/OPG system. An appropriate lifestyle from adolescence onwards, together with early diagnosis of and treatment for CD and primaryand secondary endocrine pathologies are important for the prevention of damage to the bones.  相似文献   

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PURPOSE OF REVIEW: The present review addresses recent developments that relate to the clinical management and prevention of childhood salmonellosis in developed and developing countries. RECENT FINDINGS: Invasive disease due to serovar Typhi as well as nontyphoidal salmonellae (NTS) is common in children younger than 5 years old in developing countries, and multidrug resistance is an increasingly difficult problem to manage. A new conjugate vaccine was found to be very effective in preventing typhoid fever in young Vietnamese children and was well tolerated, showing great promise for the future. Antibiotic use in the food animal industry is an important source of disease with multidrug resistant NTS strains in the developed world. Efforts for prevention are aimed at immunization of animals, control of antibiotic use in the food animal industry and careful monitoring of food-borne outbreaks. On the other hand, although the burden of NTS disease in children is far greater in developing countries, especially in tropical Africa, knowledge of even basic epidemiology is lacking. Importantly, it may be that, as spp. acquire increasing resistance, they also acquire increasing virulence that will lead to even greater morbidity and mortality. SUMMARY: Recent developments include a better knowledge of clinical aspects of invasive salmonellosis, an increasing response to the problem of multiple antibiotic resistance (including quinolones), and excellent results from the use of a recently developed conjugate vaccine for typhoid fever in children as young as 2 years old.  相似文献   

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