Search results

1

Stem cell biology - a never ending quest for understanding.

100%

Majka M., Kucia M., Ratajczak M. Z.

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2005

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vol. 52

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issue 2

353-358

EN

Stem cells (SC) research is an important part of biotechnology that could lead to the development of new therapeutic strategies. A lot of effort has been put to understand biology of the stem cells and to find genes and subsequently proteins that are responsible for their proliferation, self-renewal and differentiation. Different cytokines and growth factors has been used to expand stem cells, but no combination of these factors was identified that could effectively expand the most primitive stem cells. Recently, however, genes and receptors responsible for SC proliferation and differentiation have been described. Ligands for these receptors or these genes themselves are being already used for ex vivo expansion of stem cells and the first data are very promising. New markers, such as CXCR4 and CD133, have been discovered and shown to be present on surface of hematopoietic stem cells. The same markers were recently also found to be expressed on neuronal-, hepatic- or skeletal muscle-stem cells. By employing these markers several laboratories are trying to isolate stem cells for potential clinical use. New characteristics of stem cells such as transdifferentiation and cell fusion have been described. Our team has identified a population of tissue committed stem cells (TCSC). These cells are present in a bone marrow and in other tissues and they can differentiate into several cell types including cardiac, neural and liver cells.

2

Does senile impairment of cholinergic system in rats concern only disturbances in cholinergic phenotype or the progressive degeneration of neuronal cell bodies?

88%

Niewiadomska G., Wyrzykowska J., Chechłacz M.

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2000

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vol. 47

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issue 2

313-330

EN

The trophic effect of continuous intraventricular infusion of nerve growth factor (NGF) on morphology of the basal forebrain (BF) cholinergic neurons was tested in 4- and 28-month-old male Wistar rats. All studies were conducted using behaviorally uncharacterized animals from the same breeding colony. Immunohistochemical procedure for choline acetyltransferase (ChAT) and p75NTR receptor has been applied to identify cholinergic cells in the structures of basal forebrain (BF). Using a quantitative image analyzer, morphometric and densitometric parameters of ChAT- and p75NTR-positive cells were measured immediately after cessation of NGF infusion. In 28-month-old non-treated rats the number of intensively ChAT-positive cells in all forebrain structures was reduced by 50-70% as compared with young animals. The remaining ChAT-positive cells appeared shrunken and the neuropil staining was markedly reduced. In contrast, the same neurons when stained for p75NTR were numerous and distinctly visible with perfect morphology. Analysis of Nissl stained sections also showed that 28-month-old rats did not display significant losses of neuronal cell bodies. NGF restored the number of intensely stained ChAT-positive cells to about 90% of that for young controls and caused a significant increase in size of those cells in 28-month-old rats as compared with the control, age-matched group. NGF did not influence the morphology of p75NTR-positive neurons, which were well labeled, irrespective of treatment and age of the rats. In 4-month-old rats, NGF infusion decreased the intensity of both ChAT and p75NTR immunostaining. These data provide some evidence for preservation of BF cholinergic neurons from atrophy during aging and indicate that senile impairment of the cholinergic system in rats concerns decrease in ChAT-protein expression rather than an acute degeneration of neuronal cell bodies. Treatment with NGF resulted in restoration of cholinergic phenotype in the BF neurons of aged rats. However, the present study also rises issue of possible detrimental effects of NGF in young normal animals.

3

Effects of crumb rubber on compressive strength of cement-treated soil

71%

Wang F. C., Song W., Wang F. C., Song W.

Archives of Civil Engineering

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2015

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issue 4

4

Zastosowanie komórek macierzystych w leczeniu pacjentów z chorobą Parkinsona

63%

Rieske P.

Aktualności Neurologiczne

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2007

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vol. 7

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issue 4

232-241

EN

This review shows current progress in stem cell therapy of Parkinson disease. Article depicts strategies of stem cell therapy, discusses results of trials performed to treat Parkinson disease, describes experience of author in preparing cells for patients with Parkinson disease, and presents potential danger of stem cell therapy. Several strategies of stem cell therapies are presented. Strategies are divided in to: physiological, physiologicallybiotechnological and biotechnological. Physiological strategy includes: use of neural stem cells, and Ratajczak concept. Plasticity (transdifferentiation), is considered as approach physiologically-biotechnological. Biotechnological strategy includes: cloning and reprogramming. Article shows opinions of authorities working on Parkinson disease stem cells therapy, briefly discusses trials of Hauser et al., Hegel et al., Brundin et al., Freed et al., and Olanow et al. Clues coming from these trials, for future use of stem cells derivatives, in the treatment of Parkinson disease are presented. Hints coming from works on Parkinson disease animals models, are also included. Moreover author presents his own experience in preparing cells potentially useful in Parkinson disease treatment, which is use of fibroblasts and neural stem cells. Finally possible dangerous consequences of stem cells therapy, such as risk of cancers development, are shown. Stem cell therapy appears as progressing, but in author opinion there is no final conclusion to say if it will work very efficiently or not.

PL

W ostatnim czasie dokonał się istotny postęp w terapii komórkowej choroby Parkinsona. W niniejszym artykule przedstawiono strategie dotyczące terapii komórkowej, opisano wyniki prób klinicznych, przedstawiono także doświadczenia autora w przygotowaniu komórek dla osób z chorobą Parkinsona oraz uwypuklono niebezpieczeństwa, jakie mogą wynikać ze stosowania terapii komórkowej. Zaprezentowano takie strategie terapii komórkowej, jak: strategia fizjologiczna, strategia fizjologiczno-biotechnologiczna i strategia biotechnologiczna. W ramach strategii fizjologicznej ujęto zastosowanie neuralnych komórek macierzystych i koncepcję Ratajczaka. Plastyczność (transróżnicowanie) jest rozpatrywana jako podstawa strategii fizjologiczno-biotechnologicznej. Strategia biotechnologiczna to klonowanie i reprogramowanie. W artykule zaprezentowano także opinie autorytetów na temat skuteczności terapii komórkowej w leczeniu pacjentów z chorobą Parkinsona oraz krótko opisano próby kliniczne, którymi niezależnie od siebie kierowali: Hauser, Hegel, Brundin, Freed i Olanow. Przedstawiono również implikacje ich dokonań badawczych dla przyszłych prób wykorzystania komórek macierzystych w terapii osób z chorobą Parkinsona, jak również wyniki badań nad zwierzętami z eksperymentalnie wywołanym parkinsonizmem. Autor prezentuje ponadto wyniki własnych doświadczeń w przygotowywaniu komórek potencjalnie użytecznych w leczeniu pacjentów z chorobą Parkinsona oraz omawia istotne zagrożenia związane ze stosowaniem terapii komórkowej (takie jak choroba nowotworowa). Terapia komórkowa rozwija się, jednak w odczuciu autora niniejszego artykułu nie ma pewności, czy będzie ona naprawdę skuteczną.

5

Rewolucja w biologii rozwojowej

63%

Rieske P.

Aktualności Neurologiczne

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2006

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vol. 6

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issue 3

159-163

EN

During the last decade dozens of papers have been published, whose approval for printing signifies a consent for changes in some biology handbooks. Stem cells have found their way to newspaper headlines and even became an element of presidential campaign in the United States. Indeed, an important issue on scientific and medical ground is that recently several paradigms in hitherto force in developmental biology have been challenged. First, the paradigm of barrier between embryonal layers has been questioned. Second, it has been demonstrated that even in such structures as the central nervous system and heart muscle there is a steady but distinct renovation, even in adult mammals. Third, new models of cell differentiation have been proposed. For many years, developmental biology was based on instructional models of differentiation. At present, the instructional model is increasingly frequently replaced by the stochastic model. Furthermore, the question of debate is whether there is still any rationale for further propagation of hierarchic models. Current dispute concerning the above mentioned concepts and paradigms, which is currently taking place among biologists studying the development of organisms, has a direct transmission onto practical applications thereof. For example, lack of barrier between embryonal layers (or its permeability) paves the way for the use of mesenchymal stem cells from bone marrow as “progenitors” of neurons, whose deficit is seen in persons with Parkinson disease. In other words, if inter-embryonal layer barrier does not exist or may be transgressed, then therapeutic cloning may be substituted by simple aspiration of bone marrow or sampling of skin fibroblasts. After a few years of negation, it is accepted again that in mammals take place processes of dedifferentiation and transdifferentiation. This paper presents old paradigms as well as arguments of partisans of challenging or even to refute these paradigms.

PL

W ostatnim dziesięcioleciu opublikowano dziesiątki artykułów, których zaakceptowanie oznacza zgodę na dokonanie zmian w niektórych podręcznikach biologii. Komórki macierzyste „trafiły na pierwsze strony gazet” i stały się nawet przedmiotem kampanii prezydenckiej w Stanach Zjednoczonych. Co jednak istotne, z naukowego i medycznego punku widzenia w ostatnich latach podważonych zostało kilka paradygmatów obowiązujących dotychczas w biologii rozwojowej. Po pierwsze podważono paradygmat istnienia bariery listków zarodkowych. Po drugie stwierdzono, że nawet w obrębie takich struktur, jak ośrodkowy układ nerwowy (OUN) i mięsień sercowy, następuje powolna, ale jednak wyraźna odnowa u dorosłych ssaków. Po trzecie zaproponowano nowe modele różnicowania komórek. Przez wiele lat dominowały w biologii rozwojowej instrukcyjne modele różnicowania. W tej chwili w miejsce modelu instrukcyjnego coraz częściej wprowadza się model stochastyczny. Oprócz tego rozważa się, czy ma uzasadnienie dalsze propagowanie tzw. modeli hierarchicznych. Spór dotyczący wymienionych pojęć i paradygmatów, który toczy się wśród biologów zajmujących się rozwojem organizmów, przekłada się bezpośrednio na działania praktyczne. Przykładowo, brak bariery listków zarodkowych (lub jej nieszczelność) otwiera drogę do wykorzystania na przykład mezenchymalnych komórek macierzystych ze szpiku kostnego jako „progenitorów” neuronów, których niedobór obserwujemy u osób z chorobą Parkinsona. Innymi słowy, jeżeli bariera listków zarodkowych nie istnieje lub może być przekroczona, klonowanie terapeutyczne można zastąpić zwykłą aspiracją szpiku kostnego lub pobraniem fibroblastów skóry. Ponownie przyjęto – po kilku latach negowania tego faktu – iż w organizmach ssaków zachodzą procesy odróżnicowania (dedyferencjacji) i transróżnicowania (transdyferencjacji). W artykule przedstawiono stare paradygmaty, jak również argumenty zwolenników podważenia lub obalenia tychże paradygmatów.

6

Transcranial magnetic stimulation in the rehabilitation of motor deficits after ischemic stroke

51%

Bilik M., Waldowski K., Członkowska A.

Medical Rehabilitation

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2009

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vol. 13(1)

18-24

EN

Transcranial magnetic stimulation (TMS) was introduced to clinical practice in the 1980s and since that time has become more and more widely used. It is a noninvasive, painless brain stimulation technique that can modulate cortical excitability. It is possible to use single or paired TMS pulses, but the most promising method seems to be repetitive transcranial stimulation (rTMS) where magnetic pulses are repeated with a certain ferquency. Depending on the frequency of rTMS it is possible to activate or to inhibit the brain cortex. According to the latest research, the brain dysfunction after a stroke seems to be the matter of interhemispheric imbalance, most likely overactivation of the unaffected hemisphere. Based on this hypothesis, there are attempts to use TMS as a therapeutic tool after strokes. This review looks at the methods that use the TMS technique (rTMS – Repetitive Transcranial Magnetic Stimulation, TBS – Theta Burst Stimulation, PAS – Paired Associative Stimulation) to improve plasticity after a stroke. The effects encourage one to deepen research into TMS as a potential therapeutical tool in stroke rehabilitation. An issue of interest for future research is whether rTMS in conjunction with other stimulation parameters like standard physiotherapy could induce lasting changes in the nervous system, opening up new possibilities in rehabilitation.

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