Effects of radiation dose and nitrogen purge on collagen scaffold properties

2021 ◽  
pp. 088532822110476
Author(s):  
Nicholas J Sant ◽  
Benedikt L Proffen ◽  
Martha M Murray
Keyword(s):  
Radiation Dose ◽  
Enzymatic Degradation ◽  
Early Stage ◽  
Collagen Scaffold ◽  
Radiation Doses ◽  
Collagen Scaffolds ◽  
Banding Patterns ◽  
Soluble Collagen ◽  
Mass Fractions ◽  
Effects Of Radiation

Sterilization of medical devices is commonly performed using radiation methods. However, collagen materials can be damaged when using standard radiation doses (25 kGy). Small increases of radiation dose can allow for increases in the acceptable initial bioburden load of aseptically manufactured devices while maintaining required sterility assurance levels, which is often critical in early stage translational settings. In this study, we hypothesized that small increases in radiation dose from 15 to 20 kGy would result in significant changes to several key characteristics of collagen scaffolds. Scaffolds were manufactured by lyophilizing the pepsin digest of dense bovine connective tissue in cylindrical molds and were irradiated at either 0, 15, 17.5, or 20 kGy with an additional group packaged in nitrogen and irradiated at 17.5 kGy. Groups were evaluated for changes to the soluble collagen and glycosaminoglycan mass fractions, protein banding patterns in electrophoresis, a collagen fragmentation assay, and resistance to enzymatic degradation. All parameters were statistically analyzed using one-way analysis of variance with Tukey’s correction for multiple comparisons. The soluble collagen mass fraction was significantly decreased in the 20 kGy group; however, there was no significant effect of radiation dose or a nitrogen-rich environment on the other measured parameters, including protein banding patterns, fragmented collagen content, and resistance to enzymatic degradation. Statement of Clinical Significance: Collagen scaffolds have proven useful in clinical applications but can be damaged by standard radiation doses. Low-dose sterilization may be a viable alternative that minimally impacts key properties of these scaffolds.

scholarly journals Der Einfluß von Röntgenstrahlen auf Ophryotrocha puerilis

1965 ◽  
Vol 20 (4) ◽  
pp. 350-355
Author(s):  
A. L. Grierson ◽  
H. Querner
Keyword(s):  
Mortality Rate ◽  
Radiation Dose ◽  
Total Dose ◽  
Growth Zone ◽  
Radiation Doses ◽  
Effects Of Radiation ◽  
Sexually Mature

The polychaet, Ophryotrodia puerilis, which is easily bred in the laboratory, lends itself well to research on the effects of radiation on invertebrates. Growth, which depends on the activity of a growth zone, is accomplished by the addition of segments. It is, therefore, easily recorded quantitatively. Radiation doses up to 100,000 r (3335 r/min) were used. The effect of the radiation depends on the size of animal. In animals of 20 segments the LD 50/30 dose is about 50,000 r; in animals of 10 segments doses of 20,000 r and greater completely inhibit growth, and doses of 10,000 r inhibit the growth of smaller animals. Animals with 10 segments slight retardation of growth after 5,000 and 10,000 r, while the smaller animals do not grow after 10,000 r of radiation and have their growth significantly retarded by 5,000 r. — Eggs laid by sexually mature females treated with 50,000 r fail to develop. After 20,000 and 10,000 r the eggs laid in the first 10 days do not develop but eggs exposed later are capable of develpoment. Animals of 10 segments are fertile after 10,000 r but sterile after 20,000 r. — Fractionation of the radiation dose decreases the mortality rate and, with a total dose of 20,000 r, allows growth. — Irradiation of eggs has an effect that is dependent on the age of the embryo. Up to 9 days 1000 r are lethal; from 10 days on 2000 r have no effect on development. Irradiation with 500 r shows no effect, while two 250 r increments of dose given 48 hours apart kill eggs 2 — 10 days old.

scholarly journals Differential Effects of Low and High Radiation Dose Rates on Mouse Spermatogenesis

2021 ◽  
Vol 22 (23) ◽  
pp. 12834
Author(s):  
Min Ji Bae ◽  
Min Kook Kang ◽  
Yong Uk Kye ◽  
Jeong-Hwa Baek ◽  
Ye-Ji Sim ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Dose Rate ◽  
Early Stage ◽  
Sperm Count ◽  
Round Spermatid ◽  
High Dose Rate ◽  
High Dose ◽  
Radiation Dose Rate ◽  
Differential Effects ◽  
Effects Of Radiation

The adverse effects of radiation are proportional to the total dose and dose rate. We aimed to investigate the effects of radiation dose rate on different organs in mice. The mice were subjected to low dose rate (LDR, ~3.4 mGy/h) and high dose rate (HDR, ~51 Gy/h) radiation. LDR radiation caused severe tissue toxicity, as observed in the histological analysis of testis. It adversely influenced sperm production, including sperm count and motility, and induced greater sperm abnormalities. The expression of markers of early stage spermatogonial stem cells, such as Plzf, c-Kit, and Oct4, decreased significantly after LDR irradiation, compared to that following exposure of HDR radiation, in qPCR analysis. The compositional ratios of all stages of spermatogonia and meiotic cells, except round spermatid, were considerably reduced by LDR in FACS analysis. Therefore, LDR radiation caused more adverse testicular damage than that by HDR radiation, contrary to the response observed in other organs. Therefore, the dose rate of radiation may have differential effects, depending on the organ; it is necessary to evaluate the effect of radiation in terms of radiation dose, dose rate, organ type, and other conditions.

The Employment of 197Hg EDTA in Kidney Scanning

1965 ◽  
Vol 05 (01) ◽  
pp. 56-67
Author(s):  
I. Pál ◽  
J. Földes ◽  
I. Krasznai
Keyword(s):  
Radiation Dose ◽  
Renal Cortex ◽  
Radiation Doses ◽  
Intravenous Pyelography ◽  
Edta Complex

SummaryThe authors investigated the use of 197Hg EDTA complex for kidney scanning. They describe the physical, biological and toxicological properties of the compound; its distribution within the organism, its excretion with urine and faeces and its uptake by the kidneys. The authors have established that the renal cortex selectively secretes the material which makes it suitable for kidney scanning. Some scintigrams of both normal and pathologic kidneys are presented.Finally a detailed discussion of the dosimetry is included. The radiation doses due to 197Hg EDTA are compared with those due to 203Hg-neohydrin and to intravenous pyelography. This comparison shows clearly that the use of 197Hg EDTA considerably decreases the radiation dose to the patient.

Radiation Minimisation and Outcome Maximisation in Cardiac Computed Tomograpy

2010 ◽  
Vol 6 (1) ◽  
pp. 15
Author(s):  
James P Earls ◽  
Jonathon A Leipsic ◽  
◽  
Keyword(s):  
Radiation Dose ◽  
Dose Reduction ◽  
New Technologies ◽  
Cardiac Computed Tomography ◽  
Substantial Reduction ◽  
Radiation Doses ◽  
Tube Current ◽  
Prospective Triggering ◽  
Effective Radiation ◽  
Selection Of

Recent reports have raised general awareness that cardiac computed tomography (CT) has the potential for relatively high effective radiation doses. While the actual amount of risk this poses to the patient is controversial, the increasing concern has led to a great deal of research on new CT techniques capable of imaging the heart at substantially lower radiation doses than was available only a few years ago. Methods of dose reduction include optimised selection of user-defined parameters, such as tube current and voltage, as well as use of new technologies, such as prospective triggering and iterative reconstruction. These techniques have each been shown to lead to substantial reduction in radiation dose without loss of diagnostic accuracy. This article will review the most frequently used and widely available methods for radiation dose reduction in cardiac CT and give practical advice on their use and limitations.

In vivo Evaluation of a Collagen Scaffold Preconditioned with Adipose-derived Mesenchymal Stem Cells Used for Bone Regeneration A histological study

2018 ◽  
Vol 55 (4) ◽  
pp. 691-695
Author(s):  
Tudor Sorin Pop ◽  
Anca Maria Pop ◽  
Alina Dia Trambitas Miron ◽  
Klara Brinzaniuc ◽  
Simona Gurzu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Bone Regeneration ◽  
Histological Study ◽  
Collagen Scaffold ◽  
Bone Defects ◽  
Collagen Scaffolds ◽  
In Vivo Evaluation ◽  
Calvarial Bone ◽  
Bone Apposition

The use of collagen scaffolds and stem cells for obtaining a tissue-engineering complex has been an important concept in promoting repair and regeneration of the bone tissue. Such units represent important steps in the development of an ideal scaffold-cell complex that would sustain new bone apposition. The aim of our study was to perform a histologic evaluation of the healing of critical-sized bone defects, using a biologic collagen scaffold with adipose-derived mesenchymal stem cells, in comparison to negative controls created in the adjacent bone. We used 16 Wistar rats and according to the study design 2 calvarial bone defects were created in each animal, one was filled with collagen seeded with adipose-derived stem cells and the other one was considered negative control. During the following month, at weekly intervals, the animals were euthanized and the specimens from bone defects were histologically evaluated. The results showed that these scaffolds were highly biocompatible as only moderate inflammation no rejection reactions were observed. Furthermore, the first signs of osseous healing appeared after two weeks accompanied by angiogenesis. Collagen scaffolds seeded with adipose-derived mesenchymal stem cells can be considered a promising treatment option in bone regeneration of large defects.

scholarly journals Optimization of Collagen Chemical Crosslinking to Restore Biocompatibility of Tissue-Engineered Scaffolds

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 832
Author(s):  
Mohammad Mirazul Islam ◽  
Dina B. AbuSamra ◽  
Alexandru Chivu ◽  
Pablo Argüeso ◽  
Claes H. Dohlman ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Crosslinking Agent ◽  
Collagen Scaffold ◽  
Human Monocyte ◽  
Subsequent Treatment ◽  
Sodium Metabisulfite ◽  
Corneal Tissue ◽  
Dependent Manner ◽  
Collagen Scaffolds ◽  
Enzymatic Stability

Collagen scaffolds, one of the most used biomaterials in corneal tissue engineering, are frequently crosslinked to improve mechanical properties, enzyme tolerance, and thermal stability. Crosslinkers such as 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) are compatible with tissues but provide low crosslinking density and reduced mechanical properties. Conversely, crosslinkers such as glutaraldehyde (GTA) can generate mechanically more robust scaffolds; however, they can also induce greater toxicity. Herein, we evaluated the effectivity of double-crosslinking with both EDC and GTA together with the capability of sodium metabisulfite (SM) and sodium borohydride (SB) to neutralize the toxicity and restore biocompatibility after crosslinking. The EDC-crosslinked collagen scaffolds were treated with different concentrations of GTA. To neutralize the free unreacted aldehyde groups, scaffolds were treated with SM or SB. The chemistry involved in these reactions together with the mechanical and functional properties of the collagen scaffolds was evaluated. The viability of the cells grown on the scaffolds was studied using different corneal cell types. The effect of each type of scaffold treatment on human monocyte differentiation was evaluated. One-way ANOVA was used for statistical analysis. The addition of GTA as a double-crosslinking agent significantly improved the mechanical properties and enzymatic stability of the EDC crosslinked collagen scaffold. GTA decreased cell biocompatibility but this effect was reversed by treatment with SB or SM. These agents did not affect the mechanical properties, enzymatic stability, or transparency of the double-crosslinked scaffold. Contact of monocytes with the different scaffolds did not trigger their differentiation into activated macrophages. Our results demonstrate that GTA improves the mechanical properties of EDC crosslinked scaffolds in a dose-dependent manner, and that subsequent treatment with SB or SM partially restores biocompatibility. This novel manufacturing approach would facilitate the translation of collagen-based artificial corneas to the clinical setting.

scholarly journals Optimal Radiation Dose For Stage III Lung Cancer – Should “Definitive” Radiation Doses Be Used in the Pre-Operative Setting?

2021 ◽  
pp. 100201
Author(s):  
Areo G. Saffarzadeh ◽  
Maureen Canavan ◽  
Benjamin J. Resio ◽  
Samantha L. Walters ◽  
Kaitlin M. Flores ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Radiation Dose ◽  
Stage Iii ◽  
Radiation Doses

Diagnostic Reference Levels for Common Orthopedic Hand and Wrist Procedures Using Intraoperative mini C-arm Fluoroscopy

Hand ◽  
2021 ◽  
pp. 155894472199425
Author(s):  
Kiran R. Madhvani ◽  
Matthew J. R. Clark ◽  
Alex A. J. Kocheta
Keyword(s):  
Radiation Dose ◽  
Fracture Fixation ◽  
Wrist Fracture ◽  
Radiation Doses ◽  
Diagnostic Reference Levels ◽  
Reference Levels ◽  
Audit Data ◽  
Small Joint ◽  
Open Fixation ◽  
Phalangeal Fracture

Background: Diagnostic reference levels are radiation dose levels in medical radiodiagnostic practices for typical examinations for groups of standard-sized individuals for broadly defined types of equipment. This study aimed to contribute to national diagnostic reference levels for common hand and wrist procedures using mini C-arm fluoroscopy. Small joint and digital fracture procedure diagnostic reference levels have not been reported in significant numbers previously with procedure-level stratification. Methods: Data were collected from fluoroscopy logbooks and were cross-referenced against the audit log kept on fluoroscopy machines. A total of 603 procedures were included. Results: The median radiation dose for wrist fracture open fixation was 2.73 cGycm2, Kirschner wiring (K-wiring) procedures was 2.36 cGycm2, small joint arthrodesis was 1.20 cGycm2, small joint injections was 0.58 cGycm2, and phalangeal fracture fixation was 1.05 cGycm2. Conclusions: Wrist fracture fixation used higher radiation doses than phalangeal fracture fixation, arthrodeses, and injections. Injections used significantly less radiation than the other procedures. There are significant differences in total radiation doses when comparing these procedures in hand and wrist surgery. National and international recommendations are that institutional audit data should be collected regularly and should be stratified by procedure type. This study helps to define standards for this activity by adding to the data available for wrist fracture diagnostic reference levels and defining standards for digital and injection procedures.

Estimation of Radiation Doses in X-Ray Visualization of Biological Objects

2014 ◽  
Vol 880 ◽  
pp. 53-56 ◽  
Author(s):  
Sergei Stuchebrov ◽  
Andrey Batranin ◽  
Dan Verigin ◽  
Yelena Lukyanenko ◽  
Maria Siniagina ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Biological Object ◽  
Gas Discharge ◽  
Radiation Doses ◽  
Semiconductor Detectors ◽  
Interior Structure ◽  
Dose Calculations ◽  
Object Control ◽  
X Ray ◽  
Biological Objects

Two setups for X-ray visualization of objects interior structure were designed and assembled in TPU. These radiographic systems are based on linear gas-discharge and GaAs semiconductor detectors. During investigation of biological object control of radiation doses has a high priority. In this report radiation dose calculations in X-ray visualization are presented. These calculation also includes dose calculations of sinograms which are used for reconstruction of tomography slices.

scholarly journals Low-Dose Computed Tomography for the Optimization of Radiation Dose Exposure in Patients with Crohn’s Disease

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Richard G. Kavanagh ◽  
John O’Grady ◽  
Brian W. Carey ◽  
Patrick D. McLaughlin ◽  
Siobhan B. O’Neill ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Crohn’S Disease ◽  
Image Quality ◽  
Crohn's Disease ◽  
Radiation Dose ◽  
Ionizing Radiation ◽  
Low Dose ◽  
Radiation Doses ◽  
Radiation Dose Exposure ◽  
Ct Technology

Magnetic resonance imaging (MRI) is the mainstay method for the radiological imaging of the small bowel in patients with inflammatory bowel disease without the use of ionizing radiation. There are circumstances where imaging using ionizing radiation is required, particularly in the acute setting. This usually takes the form of computed tomography (CT). There has been a significant increase in the utilization of computed tomography (CT) for patients with Crohn’s disease as patients are frequently diagnosed at a relatively young age and require repeated imaging. Between seven and eleven percent of patients with IBD are exposed to high cumulative effective radiation doses (CEDs) (>35–75 mSv), mostly patients with Crohn’s disease (Newnham E 2007, Levi Z 2009, Hou JK 2014, Estay C 2015). This is primarily due to the more widespread and repeated use of CT, which accounts for 77% of radiation dose exposure amongst patients with Crohn’s disease (Desmond et al., 2008). Reports of the projected cancer risks from the increasing CT use (Berrington et al., 2007) have led to increased patient awareness regarding the potential health risks from ionizing radiation (Coakley et al., 2011). Our responsibilities as physicians caring for these patients include education regarding radiation risk and, when an investigation that utilizes ionizing radiation is required, to keep radiation doses as low as reasonably achievable: the “ALARA” principle. Recent advances in CT technology have facilitated substantial radiation dose reductions in many clinical settings, and several studies have demonstrated significantly decreased radiation doses in Crohn’s disease patients while maintaining diagnostic image quality. However, there is a balance to be struck between reducing radiation exposure and maintaining satisfactory image quality; if radiation dose is reduced excessively, the resulting CT images can be of poor quality and may be nondiagnostic. In this paper, we summarize the available evidence related to imaging of Crohn’s disease, radiation exposure, and risk, and we report recent advances in low-dose CT technology that have particular relevance.

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