scholarly journals Developing a preclinical model to evaluate the results of ridge preservation techniques

2015 ◽  
Vol 61 (1) ◽  
pp. 84-90
Author(s):  
C. Cioban ◽  
◽  
R.S. Câmpian ◽  
Ş.A. Petruţiu ◽  
A. Roman ◽  
...  

Preclinical tests required for the qualification of a biomaterial, designed for tissue-engineering approaches and regenerative medicine, for human trials are generally directed toward the evaluation of the device in animal models that approach the specific clinical application which the device is to be used. Depending on the knowledge in the field and previous data on product one can choose the appropriate model to screen the potential of the biomaterial. The protocols that are now accepted as standardized screening tests are those specific protocols which have been „validated“ through repeated use by different groups and for which consistent results were generated. Our team planned an ample preclinical research to evaluate the post-extraction healing when ridge preservation was performed using different biomaterials. Because these materials have been already tested and used in clinical practice and many data sustain their biocompatibility, we chose to perfect a canine model because: almost all preclinical studies on ridge preservation have been performed on the dog; the alveolar ridge has a similar shape to that of humans; the healing process of the extraction socket is obviously the same as humans and has already been extensively described; the roots of the experimental teeth can be easily removed. Our team studied the early healing qualitative phenomena and the late-healing qualitative and quantitative (dimensional) modifications of the ridges when different ridge preservation approaches were applied. The presented animal model that we perfected was validated by the publication of the results of our research in prestigious journals.

2003 ◽  
Vol 1248 ◽  
pp. 385-387 ◽  
Author(s):  
Amir Pourzarandian ◽  
Hisashi Watanabe ◽  
Akira Aoki ◽  
Shizuko Ichinose ◽  
Katia M. Sasaki ◽  
...  

2020 ◽  
pp. 137-148
Author(s):  
Василий Воронцов

Поводом для написания данной статьи послужила обеспокоенность автора состоянием богослужения в наши дни. Причём тревогу вызывает не сокращение объёма литургических текстов, а потеря понимания и чувства значимости некоторых из них. Отсюда, естественно, развивается достаточно вольное отношение к ним и, соответственно, небрежное исполнение их во время богослужения. После краткого упоминания о том, как должна совершаться служба Богу, автор переходит к основному предмету статьи. А она посвящена ектении как важнейшей части почти всех особо значимых богослужебных чинов Православной Церкви. В публикации представлены виды ектений, дана характеристика их содержания, показано их место во всех службах, где они встречаются, выявляется их особая роль среди множества других молитвословий, из которых состоит то или иное богослужение. Особое внимание уделено причине неоднократного употребления ектений в составе канонов утрени. Здесь ектении призваны снять напряжение внимания при исполнении подряд большого количества тропарей. В наибольшей степени это относится к канону в первый день Пасхи. Неслучайно, только на этой службе ектении произносятся после каждой песни канона. Кроме этого, в статье даётся обоснование неоднократного произнесения ектений и на службах, не относящихся к суточному кругу, каковы ми являются все пространные чинопоследования Требника, такие как службы таинств Крещения и Венчания, чины отпевания усопших, молебные пения. Отдельно отмечается образ исполнения ектении священнослужителями и хором. При этом особый акцент делается на те изъяны при совершении богослужения, которые укоренились почти во всех современных храмах. The reason for writing this article was the author’s concern about the state of Orthodox divine service in our days. Moreover, it is not the reduction in the volume of liturgical texts that causes concern, but the loss of understanding and a sense of the significance of some of them. Of course, this follows a rather free attitude to them and their careless performance during the worship service. After a brief mention of how the worship service to God should be performed, the author proceeds to the main subject of the article. And it is dedicated to the litany as the most important part of almost all particularly important liturgical ranks rites of the Orthodox Church. The publication presents the types of litanies, describes their content, shows their place in all wor ship services where they occur, and reveals their special role among the many other prayers of which this or that Orthodox divine service consists. Special attention is paid to the reason for the repeated use of litanies in the canons of Matins. Here litanies are designed to relieve the stress of attention when performing a large number of troparia in a row. To the greatest extent it relates to The Canon of Easter in the first day of Easter. It is no coincidence that only at this worship ser vice litanies are pronounced after each song of the canon of Matins. In addition, the article justi fies the repeated pronunciation of litanies also in worship services not related to the daily circle, which are all the lengthy extensive ranks rites Orthodox Breviary (Trebnik), such as the services of the sacraments of Baptism and Marriage, the funeral rites for the deads, prayer services. The ar ticle separately notes the manner of litany execution by the clergy and choir. At the same time, special attention is paid to those shortcomings in the worship that are rooted in almost all mod ern Orthodox temples.


PEDIATRICS ◽  
1991 ◽  
Vol 87 (3) ◽  
pp. 317-322 ◽  
Author(s):  
Frances P. Glascoe

Pediatricians often rely on clinical judgment derived from observation or parental concern to identify children with developmental problems. The less popular but recommended alternative is to repeatedly administer standardized screening tests. Such tests are time consuming but, unlike clinical judgment, have known detection rates. Preliminary research concerning clinical judgment showed that clusters of parental concerns related to their childrens' performances on screening tests. In the present study, previous research was refined by assessment of the meaning of parents' concerns about their childrens' speech-language development. In this study of 157 families seeking pediatric care, 72% of children whose speech-language screening yielded positive results had parents who were concerned about their speech-language development. Of children with negative screening results, 83% had parents with no concerns about their speech-language development. Although standardized screening tests should be used occasionally in the developmental surveillance process, the findings show that the problems of most children with developmental problems were detected through clinical judgment based on parental concern.


Author(s):  
Alex Solderer ◽  
Benjamin E. Pippenger ◽  
Marcel Donnet ◽  
Daniel Wiedemeier ◽  
Liza L. Ramenzoni ◽  
...  

Abstract Objectives To evaluate the effectiveness of mechanical debridement and/or air polishing on the healing of ligature-induced buccal periimplantitis dehiscence defects in dogs. Material and methods Forty-eight implants were placed in the mandibles of twelve beagle dogs, and periimplantitis was induced for 2 months using ligatures. The resulting buccal dehiscence-type defects were surgically cleaned and augmented (xenogenic filler and resorbable membrane) according to one of the following treatments: (1) Cleaning with carbon curette (debridement - D) and guided bone regeneration (GBR/G): DG, (2) air polishing cleaning (A) and GBR: AG, (3) a combination of D/A/G: DAG, and (4) D/A without GBR: DA. After 2 months, histomorphometric and inflammatory evaluations were conducted. Results The median bone gain after therapy ranged between 1.2 mm (DG) and 2.7 mm (AG). Relative bone gain was between 39% (DG) and 59% (AG). The lowest inflammation scores were obtained in DA without GBR (5.84), whereas significantly higher values between 8.2 and 9.4 were found in the groups with augmentation. At lingual sites without defects, scores ranged from 4.1 to 5.9. According to ISO, differences above 2.9 were considered representative for irritative properties. Conclusions All treatments resulted in partial regeneration of the defects. No treatment group showed a significantly (p < 0.05) better outcome. However, pretreatment with air polishing showed a tendency for less inflammation. Noteworthy, inflammation assessment showed an overall irritative potential after GBR in the evaluated early healing phase. Clinical relevance Periimplantitis treatment still represents a big issue in daily practice and requires additional preclinical research in order to improve treatment concepts.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Adam A. Garrow ◽  
Jack P. M. Andrews ◽  
Zaniah N. Gonzalez ◽  
Carlos A. Corral ◽  
Christophe Portal ◽  
...  

Abstract Dosimetry models using preclinical positron emission tomography (PET) data are commonly employed to predict the clinical radiological safety of novel radiotracers. However, unbiased clinical safety profiling remains difficult during the translational exercise from preclinical research to first-in-human studies for novel PET radiotracers. In this study, we assessed PET dosimetry data of six 18F-labelled radiotracers using preclinical dosimetry models, different reconstruction methods and quantified the biases of these predictions relative to measured clinical doses to ease translation of new PET radiotracers to first-in-human studies. Whole-body PET images were taken from rats over 240 min after intravenous radiotracer bolus injection. Four existing and two novel PET radiotracers were investigated: [18F]FDG, [18F]AlF-NOTA-RGDfK, [18F]AlF-NOTA-octreotide ([18F]AlF-NOTA-OC), [18F]AlF-NOTA-NOC, [18F]ENC2015 and [18F]ENC2018. Filtered-back projection (FBP) and iterative methods were used for reconstruction of PET data. Predicted and true clinical absorbed doses for [18F]FDG and [18F]AlF-NOTA-OC were then used to quantify bias of preclinical model predictions versus clinical measurements. Our results show that most dosimetry models were biased in their predicted clinical dosimetry compared to empirical values. Therefore, normalization of rat:human organ sizes and correction for reconstruction method biases are required to achieve higher precision of dosimetry estimates.


2011 ◽  
Vol 9 (02) ◽  
pp. 107-110 ◽  
Author(s):  
Atsushi Ishida ◽  
Moses Wu ◽  
Qun Shi ◽  
Yuji Fujita ◽  
Lester Sauvage ◽  
...  

2020 ◽  
Vol 117 (35) ◽  
pp. 21681-21689 ◽  
Author(s):  
David J. Schaeffer ◽  
Yuki Hori ◽  
Kyle M. Gilbert ◽  
Joseph S. Gati ◽  
Ravi S. Menon ◽  
...  

With the medial frontal cortex (MFC) centrally implicated in several major neuropsychiatric disorders, it is critical to understand the extent to which MFC organization is comparable between humans and animals commonly used in preclinical research (namely rodents and nonhuman primates). Although the cytoarchitectonic structure of the rodent MFC has mostly been conserved in humans, it is a long-standing question whether the structural analogies translate to functional analogies. Here, we probed this question using ultra high field fMRI data to compare rat, marmoset, and human MFC functional connectivity. First, we applied hierarchical clustering to intrinsically define the functional boundaries of the MFC in all three species, independent of cytoarchitectonic definitions. Then, we mapped the functional connectivity “fingerprints” of these regions with a number of different brain areas. Because rats do not share cytoarchitectonically defined regions of the lateral frontal cortex (LFC) with primates, the fingerprinting method also afforded the unique ability to compare the rat MFC and marmoset LFC, which have often been suggested to be functional analogs. The results demonstrated remarkably similar intrinsic functional organization of the MFC across the species, but clear differences between rodent and primate MFC whole-brain connectivity. Rat MFC patterns of connectivity showed greatest similarity with premotor regions in the marmoset, rather than dorsolateral prefrontal regions, which are often suggested to be functionally comparable. These results corroborate the viability of the marmoset as a preclinical model of human MFC dysfunction, and suggest divergence of functional connectivity between rats and primates in both the MFC and LFC.


2016 ◽  
Vol 371 (1688) ◽  
pp. 20150119 ◽  
Author(s):  
Donna L. Maney

The idea of sex differences in the brain both fascinates and inflames the public. As a result, the communication and public discussion of new findings is particularly vulnerable to logical leaps and pseudoscience. A new US National Institutes of Health policy to consider both sexes in almost all preclinical research will increase the number of reported sex differences and thus the risk that research in this important area will be misinterpreted and misrepresented. In this article, I consider ways in which we might reduce that risk, for example, by (i) employing statistical tests that reveal the extent to which sex explains variation, rather than whether or not the sexes ‘differ’, (ii) properly characterizing the frequency distributions of scores or dependent measures, which nearly always overlap, and (iii) avoiding speculative functional or evolutionary explanations for sex-based variation, which usually invoke logical fallacies and perpetuate sex stereotypes. Ultimately, the factor of sex should be viewed as an imperfect, temporary proxy for yet-unknown factors, such as hormones or sex-linked genes, that explain variation better than sex. As scientists, we should be interested in discovering and understanding the true sources of variation, which will be more informative in the development of clinical treatments.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Ahmad Jabir Rahyussalim ◽  
Aldo Fransiskus Marsetio ◽  
Ifran Saleh ◽  
Tri Kurniawati ◽  
Yudan Whulanza

Today, orthopaedics is still in search for the most reliable biomaterial for prosthesis. The biomaterial needs to have good longevity and other supporting properties in order to maintain low implant failure. An ideal metallic biomaterial should be biocompatible, has similar elastic modulus to that of bone, has excellent resistance to fatigue, corrosion, aseptic loosening, and wear, and has good bone-bonding ability. The success of an implant depends on many factors. Good osseointegration is one of the factors required to reduce the rate of loosening of implants and in order to increase the chance of osseointegration, high stability of implants and early healing process encouragement are needed.


Sign in / Sign up

Export Citation Format

Share Document