| 1. |
- Hollmark, Malin, et al.
(author)
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A comparison of radiobiological models for light ion therapy
- 2007
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In: The 11th Workshop of Ion Beams in Biology and Medicine, 25-29 September 2007, Heidelberg, Germany, ISSN 1013-4506, p. 47 (2007).
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Conference paper (pop. science, debate, etc.)abstract
- Treatment planning for light ion therapy requires development of radiobiological models describing the effects of light ion irradiation on cellular survival. The aim of this work is to compare some of these radiobiological models currently in use. The benchmark cell line used in these studies is an AA human melanoma cell line, irradiated in vitro under aerobic conditions by 60Co and 10B5+ ions of different values of linear energy transfer (40, 80, 125 and 160 keV/μm). The models used to analyze the data were: the standard linear-quadratic (LQ) model, the repairable-conditionally repairable (RCR) model, the probabilistic two-stage (P2S) model, Katz’s cellular track structure theory (TST), and the local effect model (LEM).
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| 2. |
- Rhodin, Malin M., et al.
(author)
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Human renal function maturation : a quantitative description using weight and postmenstrual age
- 2009
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In: Pediatric nephrology (Berlin, West). - : Springer Science and Business Media LLC. - 0931-041X .- 1432-198X. ; 24:1, s. 67-76
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Journal article (peer-reviewed)abstract
- This study pools published data to describe the increase in glomerular filtration rate (GFR) from very premature neonates to young adults. The data comprises measured GFR (using polyfructose, Cr-51-EDTA, mannitol or iohexol) from eight studies (n=923) and involved very premature neonates (22 weeks postmenstrual age) to adulthood (31 years). A nonlinear mixed effects approach (NONMEM) was used to examine the influences of size and maturation on renal function. Size was the primary covariate, and GFR was standardized for a body weight of 70 kg using an allometric power model. Postmenstrual age (PMA) was a better descriptor of maturational changes than postnatal age (PNA). A sigmoid hyperbolic model described the nonlinear relationship between GFR maturation and PMA. Assuming an allometric coefficient of 3/4, the fully mature (adult) GFR is predicted to be 121.2 mL/min per 70 kg [95% confidence interval (CI) 117-125]. Half of the adult value is reached at 47.7 post-menstrual weeks (95% CI 45.1-50.5), with a Hill coefficient of 3.40 (95% CI 3.03-3.80). At 1-year postnatal age, the GFR is predicted to be 90% of the adult GFR. Glomerular filtration rate can be predicted with a consistent relationship from early prematurity to adulthood. We propose that this offers a clinically useful definition of renal function in children and young adults that is independent of the predictable changes associated with age and size.
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| 3. |
- Lyssenko, Valeriya, et al.
(author)
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Common variant in MTNR1B associated with increased risk of type 2 diabetes and impaired early insulin secretion.
- 2009
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 41:1, s. 82-88
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Journal article (peer-reviewed)abstract
- Genome-wide association studies have shown that variation in MTNR1B (melatonin receptor 1B) is associated with insulin and glucose concentrations. Here we show that the risk genotype of this SNP predicts future type 2 diabetes (T2D) in two large prospective studies. Specifically, the risk genotype was associated with impairment of early insulin response to both oral and intravenous glucose and with faster deterioration of insulin secretion over time. We also show that the MTNR1B mRNA is expressed in human islets, and immunocytochemistry confirms that it is primarily localized in beta cells in islets. Nondiabetic individuals carrying the risk allele and individuals with T2D showed increased expression of the receptor in islets. Insulin release from clonal beta cells in response to glucose was inhibited in the presence of melatonin. These data suggest that the circulating hormone melatonin, which is predominantly released from the pineal gland in the brain, is involved in the pathogenesis of T2D. Given the increased expression of MTNR1B in individuals at risk of T2D, the pathogenic effects are likely exerted via a direct inhibitory effect on beta cells. In view of these results, blocking the melatonin ligand-receptor system could be a therapeutic avenue in T2D.
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| 4. |
- Quiding-Järbrink, Marianne, 1964, et al.
(author)
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Decreased IgA antibody production in the stomach of gastric adenocarcinoma patients.
- 2009
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In: Clinical immunology. - : Elsevier BV. - 1521-7035 .- 1521-6616. ; 131:3, s. 463-71
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Journal article (peer-reviewed)abstract
- Gastric adenocarcinoma is closely associated with Helicobacter pylori infection. It is also much more frequent in patients with common variable immunodeficiency or selective IgA-deficiency than in the general population. To investigate a possible link between local antibody production and gastric tumors, we studied gastric B cell infiltration and local IgA production in patients with H. pylori induced gastric adenocarcinomas. These studies showed that total and H. pylori-specific IgA antibody levels were substantially lower in gastric tissue from the cancer patients compared to those from asymptomatic H. pylori carriers. However, serum IgA levels were similar in the cancer patients and asymptomatic carriers. As could be expected, H. pylori infected asymptomatic carriers had considerably increased IgA antibody levels compared to uninfected subjects. We conclude that patients suffering from gastric adenocarcinoma have a dramatically decreased local IgA production in the stomach compared to asymptomatic H. pylori infected individuals.
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| 5. |
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| 6. |
- Fex, Malin, et al.
(author)
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Rat insulin promoter 2-Cre recombinase mice bred onto a pure C57BL/6J background exhibit unaltered glucose tolerance
- 2007
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In: Journal of Endocrinology. - 1479-6805. ; 194:3, s. 551-555
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Journal article (peer-reviewed)abstract
- beta-Cell-specific gene targeting is a widely used tool when studying genes involved in beta-cell function. For this purpose, several conditional beta-cell knockouts have been generated using the rat insulin promoter 2-Cre recombinase (RIP2-Cre) mouse. However, it was recently observed that expression of Cre alone in P-cells may affect whole body glucose homeostasis. Therefore, we investigated glucose homeostasis, insulin secretion, and beta-cell mass in our line of RIP2-Cre mice bred onto the C57BL/6J genetic background. We used 12- and 28-week-old female RIP2-Cre mice for analyses of insulin secretion in vitro, glucose homeostasis in vivo and beta-cell mass. Our mouse line has been backcrossed for 14 generations to yield a near 100% pure C57BL/6J background. We found that fasting plasma glucose and insulin levels were similar in both genotypes. An i.v. glucose tolerance test revealed no differences in glucose clearance and insulin secretion between 12-week-old RIP2-Cre and WT mice. Moreover, insulin secretion hi vitro in islets isolated from 28-week-old RIP2-Cre mice and controls was similar. In addition, beta-cell mass was not different between the two genotypes at 28 weeks of age. In our experiments, we observed no differences in glucose tolerance, insulin secretion in vivo and in vitro, or in beta-cell mass between the genotypes. As our RIP2-Cre mice are on a near 100% pure genetic background (C57BL/6J), we suggest that the perturbations in glucose homeostasis previously reported in RIP2-Cre mouse lines can be accounted for by differences in genetic background.
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| 7. |
- Gustavsson, Malin, 1975, et al.
(author)
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Global gene expression in the developing rat brain after hypoxic preconditioning: involvement of apoptotic mechanisms?
- 2007
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In: Pediatr Res. ; 61:4, s. 444-50
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Journal article (peer-reviewed)abstract
- Exposure to hypoxia before hypoxia-ischemia (HI) confers substantial protection referred to as preconditioning (PC). We hypothesized that PC induces critical changes of genes related to apoptotic cell death to render the brain more resistant. PC hypoxia (8% O2, 36 degrees C, 3 h) was induced in rats on postnatal day (PND) 6, and the rats were killed at 0, 2, 8, and 24 h. Total RNA was extracted from cerebral cortex and analyzed using Affymetrix rat genome 230 2.0 array. PC induced significant changes in 906 genes at 0 h, 927 at 2 h, 389 at 8 h, and 114 at 24 h. Ontology analysis revealed significant alterations in genes involved in cell communication, signal transduction, transcription, phosphorylation, and transport. Genes involved in cell death/apoptosis as well as those related to brain development (cell differentiation, neurogenesis, organogenesis, blood vessel development) were overrepresented. A detailed analysis demonstrated that 77 significantly regulated genes were involved in apoptosis, specifically related to the Bcl-2 family, JNK pathway, trophic factor pathways, inositol triphosphate (PI3) kinase/Akt pathway, extrinsic or intrinsic pathway, or the p53 pathway. The study supports that the epidermal growth factor receptor family, mitogen-activated protein kinase phosphatases, and Bcl-2-related proteins and the PI3 kinase/Akt pathway may have roles in providing resistance in the developing central nervous system (CNS).
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| 8. |
- Gustavsson, Malin, 1975, et al.
(author)
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Vascular response to hypoxic preconditioning in the immature brain
- 2007
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In: J Cereb Blood Flow Metab. ; 27:5, s. 928-38
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Journal article (peer-reviewed)abstract
- We hypothesized that hypoxic preconditioning (PC) modifies the microvasculature in the immature brain and thereby affects the cerebral blood flow (CBF) during a subsequent hypoxic-ischemic (HI) insult. On postnatal day 6 rats were exposed to hypoxia (36 degrees C, 8.0% O2) or normoxia for 3 h. Unilateral HI (unilateral carotid ligation and 8% hypoxia) was induced 24 h later. Cortical CBF was measured with the 14C-iodoantipyrine technique (at the end of HI) or with laser Doppler flowmetry (Perimed PF5001) before and during HI. At 0, 2, 8, and 24 h cerebral cortex was sampled and analyzed with gene arrays (Affymetrix 230 2.0). L-nitroarginine or vehicle was administrated before hypoxic PC or 30 mins before HI followed by CBF measurement (laser Doppler) during subsequent HI. Twenty-four hours after PC animals were perfusion-fixed and brains immunolabeled for von Willebrand factor and vascular density was determined by stereological quantification. The decrease in CBF during HI was attenuated significantly in PC versus control animals (P<0.01), as detected by both techniques. Several vascular genes (Angpt2, Adm, Apln, Vegf, Flt1, Kdr, Pdgfra, Agtrap, Adora2a, Ednra, serpine1, caveolin, Id1, Prrx1, Ero1l, Acvrl1, Egfl7, Nudt6, Angptl4, Anxa2, and NOS3) were upregulated and a few (Csrp2, Adora2b) were downregulated after PC. A significant increase in vascular density (P<0.05) was seen after PC. Nitric oxide synthase inhibition did not affect CBF during HI after PC. In conclusion, hypoxic PC upregulates vascular genes, increases vascular density and attenuates the decrease of CBF during a subsequent HI, which could contribute to tolerance.
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| 9. |
- Hansson, Malin, 1967, et al.
(author)
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CCL28 is increased in human Helicobacter pylori induced gastritis and mediates recruitment of gastric IgA-secreting cells.
- 2008
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In: Infection and Immunity. - 0019-9567. ; 76:7, s. 3304-11
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Journal article (peer-reviewed)abstract
- Human Helicobacter pylori infection gives rise to an active chronic gastritis and is a major risk factor for the development of duodenal ulcer disease and gastric adenocarcinoma. The infection is accompanied by a large accumulation of immunoglobulin A (IgA)-secreting cells in the gastric mucosa, and following mucosal immunization only H. pylori-infected volunteers mounted a B-cell response in the gastric mucosa. To identify the signals for recruitment of gastric IgA-secreting cells, we investigated the gastric production of CCL28 (mucosa-associated epithelial chemokine) and CCL25 (thymus-expressed chemokine) in H. pylori-infected and uninfected individuals and the potential of gastric B-cell populations to migrate toward these chemokines. Gastric tissue from H. pylori-infected individuals contained significantly more CCL28 protein and mRNA than that from uninfected individuals, while CCL25 levels remained unchanged. Chemokine-induced migration of gastric lamina propria lymphocytes isolated from patients undergoing gastric resection was then assessed using the Transwell system. IgA-secreting cells and IgA+ memory B cells from H. pylori-infected tissues migrated toward CCL28 but not CCL25, while the corresponding cells from uninfected patients did not. Furthermore, IgG-secreting cells from H. pylori-infected patients did not migrate to CCL28 but instead to CXCL12 (SDF-1). However, chemokine receptor expression did not correlate to the migratory pattern of the different B-cell populations. These studies are the first to show increased CCL28 production during gastrointestinal infection in humans and provide an explanation for the large influx of IgA-secreting cells to the gastric mucosa in H. pylori-infected individuals.
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| 10. |
- Hultcrantz, Monica, et al.
(author)
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Interferons induce an antiviral state in human pancreatic islet cells
- 2007
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In: Virology. - : Elsevier BV. - 0042-6822 .- 1096-0341. ; 367:1, s. 92-101
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Journal article (peer-reviewed)abstract
- Enterovirus infections, in particular those with Coxsackieviruses, have been linked to the development of type 1 diabetes (T1D). Although animal models have demonstrated that interferons (IFNs) regulate virus-induced T1D by acting directly on the beta cell, little is known on the human pancreatic islet response to IFNs. Here we show that human islet cells respond to IFNs by expressing signature genes of antiviral defense. We also demonstrate that they express three intracellular sensors for viral RNA, the toll like receptor 3 (TLR3) gene, the retinoic acid-inducible gene I (RIG-I) and the melanoma differentiation-associated gene-5 (MDA-5), which induce type I IFN production in infected cells. Finally, we show for the first time that the IFN-induced antiviral state provides human islets with a powerful protection from the replication of Coxsackievirus. This may be critical for beta cell survival and protection from virus-induced T1D in humans.
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