Field experiment
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Mikrocirkulace má za fyziologických i patofyziologických okolností klícovou úlohu v interakcích mezi krví a tkánemi. Pres prokázanou zásadní roli v patofyziologii a vývoji rady akutních i chronických onemocnení vcetne hypertenze, diabetu ci sepse jsou naše možnosti prímé vizualizace a rychlého funkcního vyhodnocení mikrocirkulacní síte v reálné klinické praxi velmi omezené. Orthogonal polarization spectral (OPS) imaging a vývojove ješte vylepšená metoda Sidestream dark-field (SDF) imaging jsou relativne nové optické neinvazivní technologie inkorporované do lehce ovladatelné prírucní sondy s možností vyšetrit a vizualizovat mikrocirkulaci sliznicních povrchu vcetne podjazykové krajiny u cloveka. Principy obou metod, výsledky validacních studií, soucasné možnosti využití v experimentu a v klinické praxi vcetne výhod a technických omezení jsou probírány v této práci.
Microcirculation plays an essential role in the interaction between the blood and target tissues. Despite its evident importance in the pathophysiology and development of numerous acute and chronic diseases such as hypertension, diabetes or sepsis, currently available methods allowing direct visualization of the microcirculatory network and its assessment in clinical practice are very limited. Orthogonal polarization spectral (OPS) imaging and its improved successor Sidestream dark-field (SDF) imaging are relatively new optical non-invasive technologies incorporated in a hand-held examination probe for visualization of the mucosal surface microcirculation including the human sublingual area. The basic principles of these methods, an appraisal of the validation studies, the current options of experimental and clinical applications and the advantages and technical limitations of the methods are discussed in this review.
Cieľ práce: Retrospektívne zhodnotenie pooperačných a dlhodobých výsledkov vysokých biliodigestívnych anastomóz konštruovaných vlastnou technickou modifikáciou. Metóda: V práci je hodnotených 25 pacientov za dobu 8 rokov, ktorí mali našitú vysokú biliodigestívnu anastomózu pre klinicky manifestovaný obštrukčný ikterus alebo opakované ataky cholangoitíd. Ich podkladom bola 13x malignita hepatocholedochu, Ix striktúra hepatocholedochu po Kehrovej drenáži, Ix zápalová stenóza hepatocholedochu pri choledocholitiáze, 2x Mirizziho syndróm, 2x cysta hepatocholedochu, 4x striktúra hepatocholedochu po choledochoduodenoanastomóze 1 a hepatikolitiáza, Ix stav po cholecystogastrostomíi, Ix stav po kontúzii hepatocholedochu. Sledovaný bol bezprostredný pooperačný priebeh a komplikácie a dlhodobé prežívanie, prípadne príznaky intrahepatálnej cholestázy. Výsledky: Z 13 prípadov malignity hepatocholedochu bola 5x urobená jeho resekcia a 8x iba paliatívna anastomóza. Klasická hepatikojejunoanastomóza bola urobená 14x, anastomóza podľa Heppa-Couinauda 3x, Smithova teleskopická anastomóza 2x, Hutsonova klučka 4x, spojka na žlčovod v Rexovom recesse 2x. 2x bola pooperačná biliáma fistula, Ix mnohopočetné abscesy pečene, 3x exitus počas hospitalizácie na progresiu malignity a Ix hnisanie v rane. Dve pacientky po resekcii hepatocholedochu pre malignitu žijú 12 a 66 mesiacov. Z 12 pacientov po hepatikojejunoanastomózach pre benígnu striktúru ani jeden nemal známky pooperačnej cholestázy. Jedna pacientka zomrela za 13 mesiacov z kardiálnych príčin. Záver: Po paliatívnej hepatikojejunoanastomóze bez resekcie malignity je iba krátkodobé prežívanie. Iba po súčasnej resekcii hepatocholedochu možno očakávať ojedinelé dlhodobé prežívanie s otáznou kuratívnosťou. Konštrukcia hepatikojejunoanastomózy v našej modifikácii neviedla ani raz k biliárnej fistule. Oba prípady spojky na žlčovod v Rexovom recesse viedli k prechodnej biliárnej fistule. V prípade pochybností o dlhodobej funkcii spojky je výhodné použitie Hutsonovej kľučky.
Aim; A retrospective assessment of the post-surgical and long-term results of the high biliodigestive anasto¬ moses constructed using the authors' own technique modification. Methodology: This study evaluates 25 patient cases during an 8-year-period. The patients had high biliodigestive anastomosis affixed due to the clinically manifested obstructive icterus or due to repetitive attacks of cholangitides. The underlying causes of the attacks were malignancies of the ductus hepatocholedochus in 13 cases, a stricture of the ductus hepatocholedochus following the drainage according to Kehr in 1 case, an inflammative stenosis of the ductus hepatocholedochus during choledocholithiasis in 1 case, the Mirizzi syndrome in 2 cases, a cyst of the ductus hepatocholedochus in 2 cases, a stricture of the ductus hepatocholedochus following choledochoduodenoanastomosis in 4 cases, hepaticolithiasis in 1 case, a status after cholecystogastrostomy in 1 case, and a status after ductus hepatocholedochus contusion in 1 case. The immediate post-surgical progress and complications and the long-term survival rate, as well as any signs of the intrahepatic cholestasis, were assessed. Results: Out of the 13 cases of the hepatochodochus malignancy, in 5 cases it was resected and only in 8 cases a paliative anastomosis was performed. A classical hepaticojejunoanastomosis was performed in 14 cases. anastomosis according to Hepp-Couinaud in three cases, the Smith telescopic anastomosis in 2 cases, the Hutson loop in 4 cases, an anastomosis to the biliary duct in the recess of Rex in 2 cases. In 2 cases a post-surgical biliary fistula, once multiple liver abscesses, in 3 cases exitus due to the malignancy progress during hospitalization and once a suppurative inflammatory process in the wound appeared. Two female patients who underwent resection of the ductus hepatocholedochus due to a malignancy have been surviving for 12 and 66 months. None of the 12 patients who underwent hepaticojejunoanastomoses due to benign strictures had signs of the post-surgical cholestasis. One female patient died after 13 months following the surgery due to the cardial causes. Conclusion: The paliative hepaticojejunoanastomosis without malignancy resection is followed by a shortterm survival rate. Only following the simultaneous ductus hepatocholedochus resection, an exceptional case of a long-term patient survival may be expected, with a questionable curative effect. The hepatojejunoanastomosis construction according to our modification never caused a biliary fistula. The both cases of anastomoses to the biliary duct in the recess of Rex caused a transient biliary fistula. If in doubts about the long-term function of the anastomosis, the Hutson loop application appears to be of advantage.
- MeSH
- anastomóza chirurgická metody MeSH
- choledochostomie metody MeSH
- cholelitiáza diagnóza chirurgie MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- nádory žlučových cest diagnóza chirurgie MeSH
- nemoci žlučových cest diagnóza chirurgie MeSH
- senioři MeSH
- výsledek terapie MeSH
- zákroky plastické chirurgie metody MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- přehledy MeSH
Amodal completion enables an animal to perceive partly concealed objects as an entirety, and to interact with them appropriately. Several studies, based upon either operant conditioning or filial imprinting techniques, have shown that various animals (both mammals and birds) can perform amodal completion. Before this study, the use of amodal completion by untrained animals in the recognition of objects had not been considered. Using two feeders, we observed in a field experiment the reaction of tits to the torso of a sparrowhawk (partly occluded or an 'amputated' dummy) in two different treatments (sparrowhawk torso vs. complete dummy pigeon; and torso vs. complete dummy sparrowhawk). It is clear that the birds considered the two torso variants as predators and kept away from both of them when the second feeder offered a 'pigeon' instead. On the other hand, when a 'complete sparrowhawk' was present on the second feeder, the number of visits to the occluded torso remained low; while the number of visits to the amputated one increased threefold. Birds risked perching near what was clearly an amputated torso; while the fear of a "hiding" (occluded) torso remained unchanged, when the second feeder did not provide a safe alternative. Such discrimination between torsos requires the ability for amodal completion. Our results demonstrate that in their recognition process, the birds not only use simple sign stimuli, but also complex cognitive functions.
- MeSH
- chování zvířat MeSH
- neparametrická statistika MeSH
- percepční uzavřenost MeSH
- predátorské chování MeSH
- rozpoznávání (psychologie) MeSH
- vnímání tvaru MeSH
- zpěvní ptáci MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- MeSH
- elektromagnetická pole škodlivé účinky MeSH
- lidé MeSH
- technologie MeSH
- vystavení vlivu životního prostředí * škodlivé účinky MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- populární práce MeSH
Many plant populations have adapted to local soil conditions. However, the role of arbuscular mycorrhizal fungi is often overlooked in this context. Only a few studies have used reciprocal transplant experiments to study the relationships between soil conditions, mycorrhizal colonisation and plant growth. Furthermore, most of the studies were conducted under controlled greenhouse conditions. However, long-term field experiments can provide more realistic insights into this issue. We conducted a five-year field reciprocal transplant experiment to study the relationships between soil conditions, arbuscular mycorrhizal fungi and plant growth in the obligate mycotrophic herb Aster amellus. We conducted this study in two regions in the Czech Republic that differ significantly in their soil nutrient content, namely Czech Karst (region K) and Ceske Stredohori (region S). Plants that originated from region S had significantly higher mycorrhizal colonisation than plants from region K, indicating that the percentage of mycorrhizal colonisation has a genetic basis. We found no evidence of local adaptation in Aster amellus. Instead, plants from region S outperformed the plants from region K in both target regions. Similarly, plants from region S showed more mycorrhizal colonisation in all cases, which was likely driven by the lower nutrient content in the soil from that region. Thus, plant aboveground biomass and mycorrhizal colonisation exhibited corresponding differences between the two target regions and regions of origin. Higher mycorrhizal colonisation in the plants from region with lower soil nutrient content (region S) in both target regions indicates that mycorrhizal colonisation is an adaptive trait. However, lower aboveground biomass in the plants with lower mycorrhizal colonisation suggests that the plants from region K are in fact maladapted by their low inherent mycorrhizal colonization. We conclude that including mycorrhizal symbiosis in local adaptation studies may increase our understanding of the mechanisms by which plants adapt to their environment.
- MeSH
- aklimatizace fyziologie MeSH
- Aster fyziologie MeSH
- kořeny rostlin MeSH
- mykorhiza růst a vývoj MeSH
- půdní mikrobiologie MeSH
- symbióza fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
BACKGROUND: Field translocation experiments (i.e., the introduction of seeds or seedlings of different species into different localities) are commonly used to study habitat associations of species, as well as factors limiting species distributions and local abundances. Species planted or sown in sites where they naturally occur are expected to perform better or equally well compared to sites at which they do not occur or are rare. This, however, contrasts with the predictions of the Janzen-Connell hypothesis and commonly reported intraspecific negative plant-soil feedback. The few previous studies indicating poorer performance of plants at sites where they naturally occur did not explore the mechanisms behind this pattern. AIMS AND METHODS: In this study, we used field translocation experiments established using both seeds and seedlings to study the determinants of local abundance of four dominant species in grasslands. To explore the possible effects of intraspecific negative plant-soil feedback on our results, we tested the effect of local species abundance on the performance of the plants in the field experiment. In addition, we set up a garden experiment to explore the intensity of intraspecific as well as interspecific feedback between the dominants used in the experiment. KEY RESULTS: In some cases, the distribution and local abundances of the species were partly driven by habitat conditions at the sites, and species performed better at their own sites. However, the prevailing pattern was that the local dominants performed worse at sites where they naturally occur than at any other sites. Moreover, the success of plants in the field experiment was lower in the case of higher intraspecific abundance prior to experimental setup. In the garden feedback experiment, two of the species performed significantly worse in soils conditioned by their species than in soils conditioned by the other species. In addition, the performance of the plants was significantly correlated between the two experiments, suggesting that plant-soil feedback is a likely explanation of the patterns observed in the field. CONCLUSIONS: All of the results indicate that intraspecific negative plant-soil feedback, either biotic or abiotic, may be a key factor determining the performance of the plants in our field translocation experiment. The possible effects of negative feedback should thus be considered when evaluating results of translocation experiments in future studies.
- MeSH
- ekosystém * MeSH
- pastviny MeSH
- půda * chemie MeSH
- rostliny * MeSH
- semenáček MeSH
- zahrady MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
