| 31. |
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| 32. |
- Mahdavi, Jafar, et al.
(författare)
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Helicobacter pylori SabA adhesin in persistent infection and chronic inflammation
- 2002
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Ingår i: Science. - : American Association for the Advancement of Science. - 0036-8075 .- 1095-9203. ; 297:5581, s. 573-578
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Tidskriftsartikel (refereegranskat)abstract
- Helicobacter pylori adherence in the human gastric mucosa involves specific bacterial adhesins and cognate host receptors. Here, we identify sialyl-dimeric-Lewis x glycosphingolipid as a receptor for H. pylori and show that H. pylori infection induced formation of sialyl-Lewis x antigens in gastric epithelium in humans and in a Rhesus monkey. The corresponding sialic acid-binding adhesin (SabA) was isolated with the "retagging" method, and the underlying sabA gene (JHP662/HP0725) was identified. The ability of many H. pylori strains to adhere to sialylated glycoconjugates expressed during chronic inflammation might thus contribute to virulence and the extraordinary chronicity of H. pylori infection.
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| 33. |
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| 34. |
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| 35. |
- Daşu, Alexandru, et al.
(författare)
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Theoretical simulation of tumour oxygenation and results from acute and chronic hypoxia
- 2003
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 48:17, s. 2829-2842
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Tidskriftsartikel (refereegranskat)abstract
- The tumour microenvironment is considered to be responsible for the outcome of cancer treatment and therefore it is extremely important to characterize and quantify it. Unfortunately, most of the experimental techniques available now are invasive and generally it is not known how this influences the results. Non-invasive methods on the other hand have a geometrical resolution that is not always suited for the modelling of the tumour response. Theoretical simulation of the microenvironment may be an alternative method that can provide quantitative data for accurately describing tumour tissues. This paper presents a computerized model that allows the simulation of the tumour oxygenation. The model simulates numerically the fundamental physical processes of oxygen diffusion and consumption in a two-dimensional geometry in order to study the influence of the different parameters describing the tissue geometry. The paper also presents a novel method to simulate the effects of diffusion-limited (chronic) hypoxia and perfusion-limited (acute) hypoxia. The results show that all the parameters describing tissue vasculature are important for describing tissue oxygenation. Assuming that vascular structure is described by a distribution of inter-vessel distances, both the average and the width of the distribution are needed in order to fully characterize the tissue oxygenation. Incomplete data, such as distributions measured in a non-representative region of the tissue, may not give relevant tissue oxygenation. Theoretical modelling of tumour oxygenation also allows the separation between acutely and chronically hypoxic cells, a distinction that cannot always be seen with other methods. It was observed that the fraction of acutely hypoxic cells depends not only on the fraction of collapsed blood vessels at any particular moment, but also on the distribution of vessels in space as well. All these suggest that theoretical modelling of tissue oxygenation starting from the basic principles is a robust method that can be used to quantify the tissue oxygenation and to provide input parameters for other simulations.
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| 36. |
- Friberg, Urban, et al.
(författare)
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Fitness effects of female mate choice : preferred males are detrimental for Drosophila melanogaster females
- 2003
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Ingår i: Journal of Evolutionary Biology. - : John Wiley & Sons. - 1010-061X .- 1420-9101. ; 16, s. 797-811
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Tidskriftsartikel (refereegranskat)abstract
- The evolution of female mate choice, broadly defined to include any female behaviour or morphology which biases matings towards certain male phenotypes, is traditionally thought to result from direct or indirect benefits which females acquire when mating with preferred males. In contrast, new models have shown that female mate choice can be generated by sexual conflict, where preferred males may cause a fitness depression in females. Several studies have shown that female Drosophila melanogaster bias matings towards large males. Here, we use male size as a proxy for male attractiveness and test how female fitness is affected by reproducing with large or small males, under two different male densities. Females housed with large males had reduced lifespan and aged at an accelerated rate compared with females housed with small males, and increased male density depressed female fitness further. These fitness differences were due to effects on several different fitness components. Female fitness covaried negatively with male courtship rate, which suggests a cost of courtship. Mating rate increased with male size, whereas female fitness peaked at an intermediate mating rate. Our results suggest that female mate choice in D. melanogaster is, at least in part, a by-product of sexual conflict over the mating rate.
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| 37. |
- Knutsson, Anders, et al.
(författare)
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Postprandial responses of glucose, insulin and triglycerides : Influence of the timing of meal intake during night work
- 2002
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Ingår i: Nutrition and Health. - : SAGE Publications. - 0260-1060 .- 2047-945X. ; 16, s. 133-141
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Tidskriftsartikel (refereegranskat)abstract
- The objective was to study the postprandial responses of glucose, insulin and triglycerides to meal intake at different clock times during night work. Eleven night shift working nurses participated. Identical test meals were ingested at 19:30, 23:30 and 03:30, and contained 440 kcal/ 1860 kJ of energy (33 E% fat, 51 E% carbohydrate, 16 E% protein). The food intake was standardized three days before the first test meal. Blood samples were drawn just before the test meals were ingested and thereafter at 30, 60, 90, 120, 180 and 240 minutes. The postprandial responses were estimated as the total area under the curve (AUC) and significance testing was done using repeated measures ANOVA. The highest insulin level was found after meal intake at 23:30, and the lowest after meal intake 03:30. The glucose response showed the same pattern. The insulin response to food intake in night working nurses is more pronounced in the night compared with morning and evening. The results would have implications for metabolic and cardiovascular disorders in night workers.
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| 38. |
- Lindmark, H, et al.
(författare)
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Enteric bacteria counteract lipopolysaccharide induction of antimicrobial peptide genes.
- 2001
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Ingår i: J Immunol. - 0022-1767. ; 167, s. 6920-6923
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Tidskriftsartikel (refereegranskat)abstract
- The humoral immunity of Drosophila involves the production of antimicrobial peptides, which are induced by evolutionary conserved microbial molecules, like LPS. By using Drosophila mbn-2 cells, we found that live bacteria, including E. coli, Salmonella typhimurium, Erwinia carotovora, and Pseudomonas aeruginosa, prevented LPS from inducing antimicrobial peptide genes, while Micrococcus luteus and Streptococcus equi did not. The inhibitory effect was seen at bacterial levels from 20 per mbn-2 cell, while antimicrobial peptides were induced at lower bacterial concentrations (< or =2 bacteria per cell) also in the absence of added LPS. Gel shift experiment suggests that the inhibitory effect is upstream or at the level of the activation of the transcription factor Relish, a member of the NF-kappaB/Rel family. The bacteria have to be in physical contact with the cells, but not phagocytosed, to prevent LPS induction. Interestingly, the inhibiting mechanism is, at least for E. coli, independent of the type III secretion system, indicating that the inhibitory mechanism is unrelated to the one earlier described for YopJ from Yersinia.
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| 39. |
- Norrlin, S, et al.
(författare)
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Control of reaching movements in children and young adults with myelomeningocele
- 2004
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Ingår i: Developmental Medicine & Child Neurology. - : Wiley. - 0012-1622 .- 1469-8749. ; 93:7, s. 922-8
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to analyze the ability to programme and execute reaching movements in individuals with myelomeningocele (MMC) and in a control group. Thirty-one participants (18 males, 13 females; mean age 12 years 11 months, SD 2 years 7 months, range 9 to 19 years) with MMC and 31 participants (matched for age and sex) without disabilities were investigated. Reaching was performed with and without visual feedback toward three targets displayed on a computer screen and data were collected using a digitizing tablet linked to a computer. The kinematics of reaching were analyzed and analysis of variance was used for statistical analysis. Results showed that both groups were able to programme reaching movements under both visual conditions. Although the execution of reaching was poor in the MMC group compared with the control individuals, as indicated by larger end-point errors (p=0.002), less straight movements (p=0.018), and shorter deceleration phases (p=0.004), movement time was not prolonged in the MMC group. Those with shunt treatment (n=21) had more difficulties when visual feedback was provided. Those with symptoms of early brainstem dysfunction (n=5) had shorter deceleration phases under both visual conditions.
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| 40. |
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