Neurosci Lett. 2003 Jul 10;345(1):1-4. In vivo micro magnetic resonance imaging signal changes in scrapie infected mice.
Sadowski M, Tang CY, Aguinaldo JG, Carp R, Meeker HC, Wisniewski T.
Department of Neurology, New York University School of Medicine, 550 First Avenue, New York 10016, USA.
Signal abnormalities on magnetic resonance imaging (MRI) T2-weighted images (T2WI) have been described in patients with Creutzfeldt-Jakob disease; however, the pathology underlying these findings remains to be fully described. We investigated the time-course of signal alterations in a murine model of prion disease using in vivo 9.4 Tesla micro magnetic resonance imaging (muMRI). The topography of muMRI signal changes was correlated with the accumulation of proteinase resistant PrP(Sc) in corresponding brain sections. Increased signal intensity on T2WI was observed in the septum and in the hippocampus of presymptomatic mice 120 days post infection (dpi). Mildly symptomatic animals (150 dpi) and animals with apparent neurological deficit (180 dpi) had a greater increase of signal intensity on T2WI in the septum and the hippocampus; in addition, abnormalities in the cortex and in the thalamus were found. Neuropathological evaluation demonstrated accumulation of PrP(Sc) and astrogliosis but only minimal or no spongiform changes in structures where abnormal signal was detected. These observations suggest that early pathological changes related to the accumulation of PrP(Sc) may be detectable in presymptomatic subjects using MRI systems with higher magnetic field strength.
PMID:_12809974
Zhonghua Yi Xue Za Zhi. 2003 Feb;83(4):328-32. [The overexpression of prion protein in drug resistant gastric cancer cell line SGC7901/ADR and its significance]
[Article in Chinese]
Du JP, Jin XH, Shi YQ, Zhao YQ, Liu CJ, Cao YX, Qiao TD, Chen BJ, Fan DM.
Institute of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an 710033, Shaanxi Province, China.
OBJECTIVE: To investigate the overexpression of prion protein (PrP) in drug-resistant gastric cancer cell line SGC7901/ADR and its role in multidrug resistance in gastric cancer. METHODS: (1) The expression of PrP in SGC7901/ADR, SGC790/VCR and their parental cell line SGC7901 was detected with Northern and Western blot at the mRNA and protein level. (2) Eukaryotic sense and antisense expression vector were constructed based on DNA recombination technology and (3) introduced into SGC7901 and SGC7901/ADR cell lines through electroporation. (4) The accumulation and retention of ADR in transiently transfected cells were detected by flow cytometry. RESULTS: (1) Northern and western blot suggested significantly higher expression of PrP in SGC7901/ADR and SGC7901/VCR than that in SGC7901. (2) 48 hours after the vectors transfection, the average fluorescence intensity of Adr in transfected cells were detected. The accumalation intensity were 8.9 +/- 0.7 in BS, 6.6 +/- 0.3 in PS and 7.5 +/- 0.6 in PA. The rentention intensity were 9.3 +/- 0.6 in SGC7901, 5.9 +/- 0.5 in PS and 7.1 +/- 0.5 in PA. There were significant difference between PS and BS with P < 0.01, as well as RA and BA with P < 0.01. These data suggested that PrP gene could affect the drug accumulation in gastric cancer cells after its transfected into cells. CONCLUSION: PrP was highly expressed in gastric cancer cell lines SGC7901/ADR and SGC7901/VCR. Overexpression of PrP had certain effect on drug accumulation in gastric cancer cells.
PMID:_12812654 [PubMed - in process]
Br J Pharmacol. 2003 Jun;139(4):872-80. Selective activation by photodynamic action of cholecystokinin receptor in the freshly isolated rat pancreatic acini.
An YP, Xiao R, Cui H, Cui ZJ.
Institute of Cell Biology, Beijing Normal University, Beijing 100875, China.
1 Sulphonated aluminium phthalocyanine (SALPC) photodynamic action induces amylase secretion and permanent calcium oscillation in rat pancreatic acinar cells, because of the activation of phospholipase C or signalling proteins upstream. The aim of the present study was to investigate the involvement of muscarinic acetylcholine and cholecystokinin (CCK) receptors. 2 Muscarinic receptor antagonist atropine (10 micro M) blocked amylase secretion induced by bethanechol (100 micro M), and CCK(1) receptor antagonist (S)-N-[1-(2-fluorophenyl)-3,4,6,7-tetrahydor-4-oxo-pyrrolo-[3,2,1-jk][1,4] benzodiazepine-3yl]-1H-indole-2-carboxamide (FK480) (1 micro M) blocked amylase secretion induced by CCK (100 pM). 3 Amylase secretion induced by SALPC photodynamic action was not inhibited when atropine and FK480 were present during photodynamic action. However, addition of FK480 1 micro M after initiation of photodynamic action inhibited photodynamic amylase secretion. Bethanechol (10, 100 micro M) added after photodynamic action resulted in a full secretory response. 4 Atropine (10 nM) abolished calcium oscillation induced by bethanechol (5 micro M), and FK480 (10 nM) blocked calcium oscillation induced by CCK (10 pM). 5 Atropine up to 10 micro M was without effect on Ca(2+) oscillation triggered by photodynamic action, but these oscillations were abolished by FK480 (10 nM). FK480 (10 nM) had no effect on calcium oscillations induced by bethanechol (5 micro M). Bethanechol 5 micro M, added after FK480 blockade of photodynamic calcium oscillation, still triggered regular calcium oscillation. 6 It is concluded that SALPC photodynamic action selectively and permanently activates CCK receptor in rat pancreatic acini. Such permanent and selective modulation of signalling proteins has important implications for the treatment of pancreatitis, prion diseases, and neurodegenerative disorders.
PMID:_12813011 [PubMed - in process]
Cell Mol Biol Lett. 2003;8(2):353-62. The prion peptide forms ion channels in planar lipid bilayers.
Berest V, Rutkowski M, Rolka K, Legowska A, Debska G, Stepkowski D, Szewczyk A.
Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warszawa, Poland.
One of the hypotheses concerning the pathogenic properties of the prion protein considers its influence on cellular ion homeostasis. Using the lipid bilayer technique, the influence of prion-derived peptides on the lipid bilayer conductance was characterized. To evaluate the physiological significance and possible pathological functions of the peptides, their effect on the membrane potential and respiration rate of hippocampal mitochondria was also studied. We used a peptide bearing the human prion protein sequence YSNQNNF (PrP [169-175]), and peptide SSQNNF (PrP [170-175]) bearing a naturally-occurring mutation in position 171 [N(r)S] linked to schizoaffective diseases in humans (Samaia, H.B., Mari, J.J., Vallada, H.P., Moura R.P., Simpson A.J.G., Brentani R.R. A prion-linked psychiatric disorder. Nature 390 (1997) 241). In this report, we show that PrP [170-175] N171S increases the conductance of planar lipid bilayers. Based on the conductance of single channel currents recorded in 500/500 mM KCl (cis/trans), we found a single channel conductance of 8 to 26 pS. The native prion peptide PrP [169-175] does not form ion channels in the lipid bilayer. Neither of the peptides significantly changed the membrane potential or respiration rate of isolated rat hippocampal mitochondria. We propose a possible mechanism for channel formation by aggregation of the prion-derived peptide.
The average human scalp is covered by approximatey 100,000 hair follicles. Each hair undergoes hair cycle and normally 50-100 hairs randomly fall out a day, which is unnoticeable because lost hair is replaced by as many new hairs springing up daily.
Hair loss results from the fall out of hair from the hair follicle. Alopecia or excessive, premature hair loss is the condition caused by many factors.
Loss of hair itself may not pose critical health problems because biological role of human hair is relatively marginal. Hair on our scalp protects the head from mechanical shock, heat loss, and exposure to UV-light. The eyelashes and eyebrowes protect the eyes, and hair in the ear canal or the nasal passages help filter out particles and pathogens, thus protecting our internal organs.
However, hair does play important social role: it is one of the major determinants of our appearance and identity in daily life. Fullness of hair also implicates or manifests physical integrity and youthfulness of the person. Losing hair could have more than just emotional impacts on individuals.
The hair is a unique organ that goes through a characteristic cycle consisting of an immature phase, a growing phase called anagen, a transitional phase between the growing phase and the resting phase called catagen, and finally a resting phase called telogen in which the hair stops growing, waiting to fall out. 85-90% of hairs on our body are in anagen phase or growing phase, which lasts anywhere from two to five years. This phase is followed by a short regression phase, or catagen, which lasts 2-3 weeks. Approximately 1% of hair follicles are in catagen. Approximately 10-15% of hair follicles are in the resting phase, the telogen, which lasts about 3-5 months. Hair follicles typically goes through 10-20 asynchronous cycles during the lifetime.
Persistent loss of more than 150 hairs would consist a state of hair loss, or alopecia, albeit it could be temporary.