Advantages and Disadvantages of the Use of in Vitro/in Situ Produced DH Maize Plants

1994 ◽  
pp. 201-213 ◽  
Author(s):  
M. Beckert
Keyword(s):  
Advantages And Disadvantages ◽  
Maize Plants

The Role of Microbiology in Models of Dental Caries: Reaction Paper

1995 ◽  
Vol 9 (3) ◽  
pp. 255-269 ◽  
Author(s):  
G.H. Bowden
Keyword(s):  
Process Selection ◽  
Advantages And Disadvantages ◽  
Test Models ◽  
Plaque Development ◽  
In Vitro Systems ◽  
Selection Of

Models of the caries process have made significant contributions toward defining the roles of bacteria in caries. Microbiologists use a variety of in vitro systems to model aspects of the caries process. Also, in situ models in humans provide information on the microbiology of caries in vivo. These models do not involve the entire process leading to natural caries; consequently, the results from such studies are used to deduce the roles of bacteria in natural caries. Therefore, they can be described as Inferential Caries Models. In contrast, animal models and some clinical trials in humans involve natural caries and can be described as Complete Caries Models. Furthermore, these models are used in two distinct ways. They can be used as Exploratory Models to explore different aspects of the caries process, or as Test Models to determine the effects of anticaries agents. This dichotomy in approach to the use of caries models results in modification of the models to suit a particular role. For example, if we consider Exploratory Models, the in situ appliance in humans is superior to others for analyzing the microbiology of plaque development and demineralization in vivo. The chemostat and biofilm models are excellent for exploring factors influencing bacterial interactions. Both models can also be used as Test Models. The in situ model has been used to test the effects of fluoride on the microflora and demineralization, while the chemostat and biofilm models allow for the testing of antibacterial agents. Each model has its advantages and disadvantages and role in analysis of the caries process. Selection of the model depends on the scientific question posed and the limitations imposed by the conditions available for the study.

An Overview: The Evaluation of Formation Mechanisms, Preparation Techniques and Chemical and Analytical Characterization Methods of the In Situ Forming Implants

2020 ◽  
Vol 16 ◽  
Author(s):  
Muge Kilicarslan ◽  
Ayse Nur Buke
Keyword(s):  
New Technologies ◽  
In Vitro Dissolution ◽  
Formation Mechanisms ◽  
Liquid Form ◽  
Characterization Methods ◽  
Advantages And Disadvantages ◽  
In Situ Forming

: One of the major developments of the last decade is the preparation of in situ forming implant formulations. Injectable, biocompatible and/or biodegradable polymer based in situ implants are classified differently due to implant formation based on in vivo solid depot or formation mechanisms inducing liquid form, gel or solid depot. In this review, published studies to date regarding in situ forming implant systems were compiled and their formation mechanisms, materials and methods used, routes of administration, chemical and analytical characterizations, quality control tests and in vitro dissolution tests were compared in Tables and they were evaluated. There are several advantages and disadvantages of these dosage forms due to the formation mechanism, polymer and solvent type and the ratio used in formulations and all of these parameters were discussed separately. In addition, new generation systems developed to overcome the difficulties encountered in in situ implants have been evaluated. There are, some approved products of in situ implant preparations that can be used for different indications are available on the market and the clinical phase studies nowadays. In vitro and in vivo data obtained by the analysis of the application of new technologies in many studies evaluated in this review showed that the number of approved drugs to be used for various indications with different drugs would increase in the future.

Correlated Studies of Cellular Interactions Using TEM, Freeze Etching, and SEM

1974 ◽  
Vol 32 ◽  
pp. 320-321
Author(s):  
J. P. Revel
Keyword(s):  
Developmental Stages ◽  
Three Dimensional ◽  
Cell Movement ◽  
Cellular Interactions ◽  
Serial Sections ◽  
Cell Sheets ◽  
Freeze Etching ◽  
Early Developmental

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

In Situ Localization of PPAR Gamma and Uncoupling Protein in Mouse Embryo Sections Using Digoxigenin-Labeled Riboprobes

1996 ◽  
Vol 54 ◽  
pp. 32-33
Author(s):  
C. Jennermann ◽  
S. A. Kliewer ◽  
D. C. Morris
Keyword(s):  
Alkaline Phosphatase ◽  
Room Temperature ◽  
Uncoupling Protein ◽  
Ppar Gamma ◽  
Nuclear Hormone Receptor ◽  
Full Length ◽  
Northern Analysis ◽  
Peroxisome Proliferator

Peroxisome proliferator-activated receptor gamma (PPARg) is a member of the nuclear hormone receptor superfamily and has been shown in vitro to regulate genes involved in lipid metabolism and adipocyte differentiation. By Northern analysis, we and other researchers have shown that expression of this receptor predominates in adipose tissue in adult mice, and appears first in whole-embryo mRNA at 13.5 days postconception. In situ hybridization was used to find out in which developing tissues PPARg is specifically expressed.Digoxigenin-labeled riboprobes were generated using the Genius™ 4 RNA Labeling Kit from Boehringer Mannheim. Full length PPAR gamma, obtained by PCR from mouse liver cDNA, was inserted into pBluescript SK and used as template for the transcription reaction. Probes of average size 200 base pairs were made by partial alkaline hydrolysis of the full length transcripts. The in situ hybridization assays were performed as described previously with some modifications. Frozen sections (10 μm thick) of day 18 mouse embryos were cut, fixed with 4% paraformaldehyde and acetylated with 0.25% acetic anhydride in 1.0M triethanolamine buffer. The sections were incubated for 2 hours at room temperature in pre-hybridization buffer, and were then hybridized with a probe concentration of 200μg per ml at 70° C, overnight in a humidified chamber. Following stringent washes in SSC buffers, the immunological detection steps were performed at room temperature. The alkaline phosphatase labeled, anti-digoxigenin antibody and detection buffers were purchased from Boehringer Mannheim. The sections were treated with a blocking buffer for one hour and incubated with antibody solution at a 1:5000 dilution for 2 hours, both at room temperature. Colored precipitate was formed by exposure to the alkaline phosphatase substrate nitrobluetetrazoliumchloride/ bromo-chloroindlylphosphate.

PERFUSION OF OVARIES IN VITRO AND IN VIVO

1972 ◽  
Vol 68 (2_Supplb) ◽  
pp. S285-S309 ◽  
Author(s):  
Kurt Ahrén ◽  
Per Olof Janson ◽  
Gunnar Selstam
Keyword(s):  
Perfusion System ◽  
Perfusion Technique ◽  
Preliminary Results ◽  
Advantages And Disadvantages

ABSTRACT This paper discusses in vivo and in vitro ovarian perfusion systems described so far in the literature. The interest is not focussed primarily on the results of these studies but rather on the advantages and disadvantages of the techniques and methods used. Another part of the paper summarizes the points which are most important, in our opinion, to take into consideration when developing an in vitro perfusion technique of the ovary. The last part of the paper gives a description of and some preliminary results from an in vitro perfusion system of the rabbit ovary which is under development in this laboratory.

CONSERVATION OF RARE SPECIES PLANTS AND LICHENS IN SITU WITH PLANNED ANTHROPOGENIC ACTIVITIES: BASIC APPROACHES AND IMPLEMENTATION PRINCIPLES

2018 ◽  
Vol 12 (7-8) ◽  
pp. 38-45
Author(s):  
A. N. EFREMOV ◽  
N. V. PLIKINA ◽  
T. ABELI
Keyword(s):  
Rare Species ◽  
Technology Implementation ◽  
Technology Development ◽  
Anthropogenic Activities ◽  
Natural Habitat ◽  
Local Population ◽  
Main Stage ◽  
Social Risks

Rare species are most vulnerable to man-made impacts, due to their biological characteristics or natural resource management. As a rule, the economic impact is associated with the destruction and damage of individual organisms, the destruction or alienation of habitats. Unfortunately, the conservation of habitat integrity is an important protection strategy, which is not always achievable in the implementation of industrial and infrastructural projects. The aim of the publication is to summarize the experience in the field of protection of rare species in the natural habitat (in situ), to evaluate and analyze the possibility of using existing methods in design and survey activities. In this regard, the main methodological approaches to the protection of rare species in the natural habitat (in situ) during the proposed economic activity were reflected. The algorithm suggested by the authors for implementing the in situ project should include a preparatory stage (initial data collection, preliminary risk assessments, technology development, obtaining permitting documentation), the main stage, the content of which is determined by the selected technology and a long monitoring stage, which makes it possible to assess the effectiveness of the taken measures. Among the main risks of in situ technology implementation, the following can be noted: the limited resources of the population that do not allow for the implementation of the procedure without prior reproduction of individuals in situ (in vitro); limited knowledge of the biology of the species; the possibility of invasion; the possibility of crossing for closely related species that сo-exist in the same habitat; social risks and consequences, target species or population may be important for the local population; financial risks during the recovery of the population. The available experience makes it possible to consider the approach to the conservation of rare species in situ as the best available technology that contributes to reducing negative environmental risks.

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