Clinicians involved in conventional radiation therapy are very concerned about the dose-response relationships of normal tissues. Before proceeding to new clinical protocols, radiation biologists involved with conformal proton therapy believe it is necessary to quantify the dose response and tolerance of the organs and tissues that will be irradiated. An important focus is on the vasculature. This presentation reviews the methodology and format of using confocal microscopy and stereological methods to quantify tissue parameters, cell number, tissue volume and surface area, and vessel length using the microvasculature as a model tissue. Stereological methods and their concepts are illustrated using an ongoing study of the dose response of the microvessels in proton-irradiated hemibrain. Methods for estimating the volume of the brain and the brain cortex, the total number of endothelial cells in cortical microvessels, the length of cortical microvessels, and the total surface area of cortical microvessel walls are presented step by step in a way understandable for readers with little mathematical background. It is shown that stereological techniques, based on a sound theoretical basis, are powerful and reliable and have been used successfully.

• Klíčová slova
• NASA Discipline Radiation Health, NASA Program Biomedical Research and Countermeasures, Non-NASA Center,
• MeSH
• konfokální mikroskopie metody   MeSH
• krysa rodu Rattus MeSH
• mikrocirkulace účinky záření   MeSH
• mozek krevní zásobení   účinky záření   MeSH
• protony * MeSH
• vztah dávky záření a odpovědi MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• protony * MeSH

A simple mathematical model for calculating the concentration of mobile carbon skeletons in the shoot of soya bean plants [Glycine max (L.) Merrill cv. Ransom] was built to examine the suitability of measured net photosynthetic rates (PN) for calculation of saccharide flux into the plant. The results suggest that either measurement of instantaneous PN overestimated saccharide influx or respiration rates utilized in the model were underestimated. If neither of these is the case, end-product inhibition of photosynthesis or waste respiration through the alternative pathway should be included in modelling of CH2O influx or efflux; and even if either of these is the case, the model output at a low coefficient of leaf activity indicates that PN still may be controlled by either end-product inhibition or alternative respiration.

• Klíčová slova
• NASA Discipline Life Support Systems, NASA Discipline Number 61-10, NASA Program CELSS, Non-NASA Center,
• MeSH
• biologické modely * MeSH
• buněčné dýchání MeSH
• dusík metabolismus   MeSH
• fotosyntéza fyziologie   MeSH
• Glycine max fyziologie   MeSH
• kořeny rostlin fyziologie   MeSH
• listy rostlin fyziologie   MeSH
• matematika MeSH
• metabolismus sacharidů * MeSH
• oxid uhličitý metabolismus   MeSH
• uhlík metabolismus   MeSH
• výhonky rostlin fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Research Support, U.S. Gov't, P.H.S. MeSH
• Názvy látek
• dusík MeSH
• oxid uhličitý MeSH
• uhlík MeSH

Cartilage of the vertebrate jaw is derived from cranial neural crest cells that migrate to the first pharyngeal arch and form a dorsal "maxillary" and a ventral "mandibular" condensation. It has been assumed that the former gives rise to palatoquadrate and the latter to Meckel's (mandibular) cartilage. In anamniotes, these condensations were thought to form the framework for the bones of the adult jaw and, in amniotes, appear to prefigure the maxillary and mandibular facial prominences. Here, we directly test the contributions of these neural crest condensations in axolotl and chick embryos, as representatives of anamniote and amniote vertebrate groups, using molecular and morphological markers in combination with vital dye labeling of late-migrating cranial neural crest cells. Surprisingly, we find that both palatoquadrate and Meckel's cartilage derive solely from the ventral "mandibular" condensation. In contrast, the dorsal "maxillary" condensation contributes to trabecular cartilage of the neurocranium and forms part of the frontonasal process but does not contribute to jaw joints as previously assumed. These studies reveal the morphogenetic processes by which cranial neural crest cells within the first arch build the primordia for jaw cartilages and anterior cranium.

• Klíčová slova
• NASA Discipline Evolutionary Biology, Non-NASA Center,
• MeSH
• Ambystoma embryologie   MeSH
• barvení a značení MeSH
• barvicí látky MeSH
• biologická evoluce * MeSH
• biologické modely MeSH
• chrupavka embryologie   ultrastruktura   MeSH
• crista neuralis cytologie   MeSH
• embryo nesavčí MeSH
• fluorescein-5-isothiokyanát MeSH
• hybridizace in situ MeSH
• kuřecí embryo MeSH
• mandibula embryologie   růst a vývoj   MeSH
• maxila embryologie   růst a vývoj   MeSH
• morfogeneze MeSH
• rozvržení tělního plánu MeSH
• zelené fluorescenční proteiny MeSH
• zvířata MeSH
• Check Tag
• kuřecí embryo MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Research Support, U.S. Gov't, P.H.S. MeSH
• Názvy látek
• barvicí látky MeSH
• fluorescein-5-isothiokyanát MeSH
• zelené fluorescenční proteiny MeSH

Does space flight change gravity receptor development? The present study measured vestibular form and function in birds flown as embryos for 5 days in earth orbit (STS-29). No major changes in vestibular gross morphology were found. Vestibular response mean amplitudes and latencies were unaffected by space flight. However, the results of measuring vestibular thresholds were mixed and abnormal responses in 3 of the 8 flight animals raise important questions.

• Klíčová slova
• NASA Discipline Neuroscience, Non-NASA Center,
• MeSH
• akční potenciály MeSH
• chondroitinsulfáty metabolismus   MeSH
• fibronektiny metabolismus   MeSH
• imunohistochemie MeSH
• keratansulfát metabolismus   MeSH
• kosmický let * MeSH
• kuřecí embryo MeSH
• otolitová membrána anatomie a histologie   embryologie   fyziologie   MeSH
• sakulus a utrikulus anatomie a histologie   embryologie   fyziologie   MeSH
• stav beztíže * MeSH
• vestibulární aparát anatomie a histologie   embryologie   fyziologie   MeSH
• vestibulární vláskové buňky anatomie a histologie   embryologie   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• kuřecí embryo MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• chondroitinsulfáty MeSH
• fibronektiny MeSH
• keratansulfát MeSH

A transparent, cylindrical chamber system was developed to allow measurement of gas-exchange by small crop canopies in the undisturbed plant growth environment. The system is an elaboration of the Minitron system developed previously to compare growth of small plants in different environments within the same general growth area. The Minitron II system described herein accommodates hydroponic culture and separate control of atmospheric composition in individual chambers. Root and shoot environments are compartmented separately to accommodate atmospheres of different flow rate and/or gaseous composition. A series of 0-rings and tension-adjustable springs allow carbon dioxide in the flowing atmosphere to be analyzed without cross-contamination between chamber compartments or from external gas sources. Carbon dioxide has been maintained at set point +/- 9 g m-3 over a range of CO2 concentrations from 382 to 2725 g m-3 and with an atmosphere turnover rate of 136.7 cm3 s-1 by computer-assisted mass flow controllers. Each chamber has dimensions large enough (61 cm internal diameter, 0.151 m3 internal volume) to allow adequate replication of individual plants for statistical purposes (e.g., up to 36 equally-spaced plant holders). No significant variation in growth or photosynthetic rate of leaf lettuce occurred between chambers for a given set of environmental conditions. Gas-exchange rates in different chambers changed to a similar extent as CO2 concentration in the flowing atmosphere or chamber temperature were varied by the same amount. When coupled with appropriate control systems, Minitron II chambers can provide separate controlled environments for multiple small plants with adequate precision and at relatively low cost.

• Klíčová slova
• NASA Discipline Life Support Systems, NASA Discipline Number 61-10, NASA Program CELSS, Non-NASA Center,
• MeSH
• atmosféra MeSH
• design vybavení MeSH
• fotosyntéza fyziologie   MeSH
• hydroponie přístrojové vybavení   MeSH
• kořeny rostlin růst a vývoj   fyziologie   MeSH
• oxid uhličitý metabolismus   MeSH
• prostředí kontrolované * MeSH
• salát (hlávkový) růst a vývoj   metabolismus   fyziologie   MeSH
• systémy udržující život přístrojové vybavení   normy   MeSH
• teplota MeSH
• uzavřené ekologické systémy * MeSH
• výhonky rostlin růst a vývoj   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• oxid uhličitý MeSH