Karolinska Institutet

About: Karolinska Institutet is a education organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Population & Poison control. The organization has 46212 authors who have published 121142 publications receiving 6008130 citations.

Angiogenesis inhibited by drinking tea

Abstract: Consumption of tea has been shown to inhibit the growth of several tumour types in animals, including cancers of the lung and oesophagus1,2,3. Drinking tea, especially green tea, is also associated with a lower incidence of human cancer1. The mechanisms of cancer inhibition are not known, although several hypotheses have been proposed. We investigated whether drinking green tea could suppress angiogenesis, a process of blood-vessel growth required for tumour growth and metastasis. We find that green tea, and one of its components, epigallocatechin-3-gallate (EGCG), significantly prevents the growth of new blood vessels in animals. This finding indicates that drinking tea may be beneficial for the prevention and treatment of angiogenesis-dependent diseases, including cancer and blindness caused by diabetes.

Primary sensory neurons of the rat showing calcitonin gene-related peptide immunoreactivity and their relation to substance P-, somatostatin-, galanin-, vasoactive intestinal polypeptide- and cholecystokinin-immunoreactive ganglion cells.

Abstract: By use of the indirect immunofluorescence technique the distribution of calcitonin gene-related peptide (CGRP)-like immunoreactivity (LI) has been analyzed in cervical and lumbar dorsal root ganglia of untreated and colchicine-treated rats. In addition, lumbar ganglia were examined 2 weeks after transection of the sciatic nerve. The occurrence of CGRP-positive cells in relation to ganglion cells containing substance P-, somatostatin-, galanin-, cholecystokinin (CCK)-, and vasoactive intestinal polypeptide (VIP)/peptide histidine isoleucin (PHI)-LI has been evaluated on consecutive sections as well as using elution-restaining and double-staining techniques.

Differential expression of mRNAs for neurotrophins and their receptors after axotomy of the sciatic nerve

Abstract: The neurotrophin family includes NGF, brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4). Previous studies have demonstrated that expression of NGF and its low-affinity receptor is induced in nonneuronal cells of the distal segment of the transected sciatic nerve suggesting a role for NGF during axonal regeneration (Johnson, E. M., M. Taniuchi, and P. S. DeStefano. 1988. Trends Neurosci. 11:299-304). To assess the role of the other neurotrophins and the members of the family of Trk signaling neurotrophin receptors, we have here quantified the levels of mRNAs for BDNF, NT-3, and NT-4 as well as mRNAs for trkA, trkB, and trkC at different times after transection of the sciatic nerve in adult rats. A marked increase of BDNF and NT-4 mRNAs in the distal segment of the sciatic nerve was seen 2 wk after the lesion. The increase in BDNF mRNA was mediated by a selective activation of the BDNF exon IV promoter and adrenalectomy attenuated this increase by 50%. NT-3 mRNA, on the other hand, decreased shortly after the transection but returned to control levels 2 wk later. In Schwann cells ensheathing the sciatic nerve, only trkB mRNA encoding truncated TrkB receptors was detected with reduced levels in the distal part of the lesioned nerve. Similar results were seen using a probe that detects all forms of trkC mRNA. In the denervated gastrocnemius muscle, the level of BDNF mRNA increased, NT-3 mRNA did not change, while NT-4 mRNA decreased. In the spinal cord, only small changes were seen in the levels of neutrophin and trk mRNAs. These results show that expression of mRNAs for neurotrophins and their Trk receptors is differentially regulated after a peripheral nerve injury. Based on these results a model is presented for how the different neurotrophins could cooperate to promote regeneration of injured peripheral nerves.

Increased Brain Activity in Frontal and Parietal Cortex Underlies the Development of Visuospatial Working Memory Capacity during Childhood

Abstract: The aim of this study was to identify changes in brain activity associated with the increase in working memory (WM) capacity that occurs during childhood and early adulthood. Functional MRI (fMRI) was used to measure brain activity in subjects between 9 and 18 years of age while they performed a visuospatial WM task and a baseline task. During performance of the WM task, the older children showed higher activation of cortex in the superior frontal and intraparietal cortex than the younger children did. A second analysis found that WM capacity was significantly correlated with brain activity in the same regions. These frontal and parietal areas are known to be involved in the control of attention and spatial WM. The development of the functionality in these areas may play an important role in cognitive development during childhood.

Hypocretin/Orexin- and melanin-concentrating hormone-expressing cells form distinct populations in the rodent lateral hypothalamus: Relationship to the neuropeptide Y and agouti gene-related protein systems

Abstract: Cells in the lateral hypothalamus and in the arcuate nucleus play prominent roles in the central control of food intake; however, a neurochemical link connecting these potential components of a hypothalamic circuitry regulating energy metabolism remains to be established. In the present study, the topographical relationship between cells expressing mRNAs encoding melanin-concentrating hormone and the newly discovered neuropeptide family hypocretins/orexins was studied in the rat and mouse lateral hypothalamus by using double-labeling in situ hybridization. Cells expressing the two mRNAs formed completely distinct populations, with hypocretin/orexin cells located primarily perifornically and in the magnocellular lateral hypothalamic nucleus; melanin-concentrating hormone cells extended in a wider area both laterally and periventricularly and appeared to partly surround the hypocretin/orexin population. In the arcuate nucleus, cells expressing neuropeptide Y and agouti gene-related protein were studied by routine fluorescence and/or confocal microscopy immunohistochemistry. Double staining demonstrated that a large proportion of the neuropeptide Y-positive cell bodies in this nucleus also contained agouti gene-related protein-like immunoreactivity. Moreover, these two peptides also coexisted in nerve terminals surrounding and in close relationship to perikarya and processes of both hypocretin/orexin- and melanin-concentrating hormone-immunoreactive cells in the lateral hypothalamus, whereby the former appeared to receive a more dense innervation. These results thus provide evidence for an arcuate-lateral hypothalamic neuropeptide Y/agouti gene-related protein pathway. Furthermore, the results implicate hypocretin/orexin and melanin-concentrating hormone-expressing cells as downstream targets in neuropeptide Y-induced feeding.