Preparation of Nano-Hydroxyapatite/Poly(D,L-Lactide) Composite and Its Degradation in Femora of Rabbits

2005 ◽  
Vol 288-289 ◽  
pp. 203-206
Author(s):  
Yu Mei Xiao ◽  
Hong Song Fan ◽  
Xin Long Wang ◽  
Jin Rui Xu ◽  
Jing Qiu Cheng ◽  
...  
Keyword(s):  
Histological Analysis ◽  
Tissue Response ◽  
Key Factors ◽  
Bony Tissue ◽  
Factors Affecting ◽  
Tissue Ingrowth ◽  
Mechanism Of Degradation ◽  
Good Biocompatibility ◽  
And Control

With the outstanding biocompatibility of hydroxyapatite (HA) and biodegradation of poly(D,L)lactide(PDLLA), and the expected good bio-mechanical compatibility, nano-HA / PDLLA (n-HA/PDLLA)composite has been paid great interests in hard tissue repair. One of the key factors affecting the potential of the composite is the degradation of the composite. That is what the mechanism of degradation in the composite is and if the degradation of the materials would induce the crack of the composite or a porous structure facile for tissue ingrowth would be formed. In this study, an n-HA/ PDLLA composite containing about 40% n-HA (wt%) was prepared and the degradation of the composite in bony tissue of rabbits and tissue response were studied by implanting composite rods and control HA rods into the femora of 16 New Zealand rabbits. After definite intervals, the histological analysis was completed by light microscopy and the degradation behavior was observed by scanning electron microscopy. The results suggested that a nano-HA/PDLLA composite was obtained and the materials showed good biocompatibility and osteoconductivity. The substantial degradation of the composite occurred at 8 weeks in vivo. After a longer period of implantation, the further degradation of the composite led to the formation of interconnected microporous and macroporous structure in the materials that might facilitate the tissue ingrowth in the composite.

In Vivo Evaluation of Nano-HA/PDLLA Composite

2005 ◽  
Vol 284-286 ◽  
pp. 881-884 ◽  
Author(s):  
Yu Mei Xiao ◽  
Hong Song Fan ◽  
Yao Wu ◽  
Jin Rui Xu ◽  
Y. Tan ◽  
...  
Keyword(s):  
Histological Analysis ◽  
Sem Analysis ◽  
Albino Rats ◽  
Degradation Behavior ◽  
Porous Network ◽  
In Vivo Evaluation ◽  
Good Biocompatibility ◽  
Wistar Albino Rats ◽  
And Control

The purpose of this study was to evaluate the behavior of nano-hydroxyapatite/ poly(D,L)lactide (n-HA/PDLLA) composite in vivo. The composite rods containing about 40wt% n-HA and control HA rods with a diameter of 2mm and a length of 6mm were implanted into the femora of 16 New Zealand rabbits. Composite wafers with a diameter of 5mm and a thickness of 1mm were implanted into the dorsal subcutis of 18 Wistar Albino rats. After definite intervals, the histological analysis was completed by light microscopy and the degradation behavior was observed by scanning electron microscopy. The histological analysis showed no obvious difference between n-HA /PDLLA composite and pure HA that had good biocompatibility and osteoconductivity. SEM analysis of the surface and cross section of the samples showed that the degradation of the composite started from surface, then into the inner gradually and formed multiple pores at surface. The pore size and porosity gradually increased along with time and a porous network may be formed.

Hyperglycemic athymic nude mice: factors affecting in vitro insulin secretion

1992 ◽  
Vol 263 (6) ◽  
pp. E1131-E1133
Author(s):  
A. Zeidler ◽  
P. Edwards ◽  
J. Goldman ◽  
S. Kort ◽  
W. P. Meehan ◽  
...  
Keyword(s):  
Animal Model ◽  
Insulin Secretion ◽  
Insulin Dependent Diabetes Mellitus ◽  
Dependent Diabetes Mellitus ◽  
Factors Affecting ◽  
In Vitro Insulin Secretion ◽  
Insulin Secretion In Vitro ◽  
And Control

The strain of athymic nude male mice (ANM) developed at the University of Southern California (USC) exhibits spontaneous hyperglycemia and relative hypoinsulinemia in vivo. To investigate factors that influence insulin secretion in this animal model of non-insulin-dependent diabetes mellitus, we utilized the isolated perfused mouse pancreas of the ANM-USC and control BALB/c mice. We compared in vitro glucose-induced insulin secretion in ANM-USC and control mice, inhibition of secretion by somatostatin, and variability of insulin secretion over the two-year period it took to complete these experiments. Glucose-induced insulin secretion from the isolated pancreas was biphasic in both ANM-USC and controls. Insulin secretion was quantitatively equal to or greater than control mice, depending on the phase of secretion analyzed and the source of the control mice. In contrast to pancreases of control mice, insulin secretion from ANM-USC pancreases was relatively resistant to inhibition of insulin secretion by somatostatin. Variability in insulin secretion over the two years in which these experiments were performed was greater from pancreases of control than that observed from pancreases of the ANM-USC. The hyperglycemic ANM-USC mouse does not demonstrate diminished insulin secretion in vitro yet is relatively hypoinsulinemic in vivo. Thus circulating factors other than somatostatin might contribute to the insulinopenic stage in this animal model.

scholarly journals Impact of control technology on fight against COVID-19

2022 ◽  
Vol 355 ◽  
pp. 02044
Author(s):  
Zihuan Feng ◽  
Xun liang ◽  
Chengzhen Zhao ◽  
Jiachen Wu
Keyword(s):  
Information Management ◽  
Public Management ◽  
Prevention And Control ◽  
System Model ◽  
Control Technology ◽  
Practical Issue ◽  
Key Factors ◽  
Factors Affecting ◽  
Multiple Data ◽  
And Control

Since the outbreak of COVID-19, all countries have taken certain measures to restrain the spread of COVID-19. It is a complex and practical issue to study the measures and effects of the epidemic prevention and control. The spread of the epidemic in different countries has certain characteristics, and the prevention and control models and effects in different countries are also different. In this paper, the key factors affecting the prevention effect of COVID-19 were analyzed by integrating multiple data and using interdisciplinary methods of mathematics, statistics and information management science on the basis of public management, and the system model of influencing factors of COVID-19 was constructed.

A Review on the Application of In Vitro and In Vivo Models of Cancerous Tumors for the Study of the Hyperthermia Effect

2019 ◽  
Author(s):  
Zahra Zahedi-Tabar ◽  
Shadab Bagheri-Khoulenjani ◽  
Saeid Amanpour ◽  
Hamid Mirzadeh
Keyword(s):  
Animal Models ◽  
Cancer Site ◽  
Key Factors ◽  
In Vivo Models ◽  
Factors Affecting ◽  
Nanoparticle Distribution ◽  
Diffusion Media ◽  
Novel Method

Hyperthermia is a novel method for cancer therapy. To have the best control when heating tissues in hyperthermia, the use of magnetic nanoparticles is suggested. The local control of heat is very important in this technique, to prevent the damage of healthy tissues around the tumor, and therefore it is necessary to measure changes in temperature to determine the optimum conditions in which hyperthermia can create the desired results. The type and concentration of nanoparticles and nanoparticle distribution within the cancerous tissue are key factors affecting temperature distribution throughout the hyperthermia process. One of the main factors influencing nanoparticle distribution is the characteristics of the diffusion media, such as chemical composition, morphological and mechanical features, all of which affect the diffusion of nanoparticles at the cancer site. In this review, the most common in vitro and in vivo media and their influence on the results of hyperthermia are discussed. We also mention in silico as a computational model. Buffer solutions, cell cultures, microfluids, dead tissues and animal models are some of the in vitro media that are discussed in this review paper. In addition, some of the animal models used for hyperthermia will be mentioned.

Multiple factors affecting the efficiency of multiple ovulation and embryo transfer in sheep and goats

2004 ◽  
Vol 16 (4) ◽  
pp. 421 ◽  
Author(s):  
Antonio Gonz´lez-Bulnes ◽  
David T. Baird ◽  
Bruce K. Campbell ◽  
María J. Cocero ◽  
Rosa M. García-García ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Hormonal Treatment ◽  
Variable Number ◽  
Current Status ◽  
Factors Affecting ◽  
Intrinsic Factors ◽  
Basic Characteristics ◽  
Transfer Procedures ◽  
And Control

This review offers an overview of the basic characteristics of in vivo embryo technologies, their current status, the main findings and the advances gained in recent years, and the outstanding subjects for increasing their efficiency. The use of superovulation and embryo transfer procedures remains affected by a high variability in the ovulatory response to hormonal treatment and by a low and variable number of transferable embryos and offspring obtained. This variability has been classically identified with both extrinsic (source, purity of gonadotrophins and protocol of administration) and intrinsic factors (breed, age, nutrition and reproductive status), which are reviewed in this paper. However, emerging data indicate that the main causes of variability are related to endocrine and ovarian factors, and so the number of studies and procedures addressing a better understanding and control of these factors may be increased in the future. The accomplishment of this objective, the improvement of procedures for embryo conservation and for the selection and management of recipient females, will allow further development and application of this technology.

scholarly journals Hyperglycemic athymic nude mice: factors affecting in vitro insulin secretion

2006 ◽  
Vol 263 (6) ◽  
pp. E1131-E1133
Author(s):  
A. Zeidler ◽  
P. Edwards ◽  
J. Goldman ◽  
S. Kort ◽  
W. P. Meehan ◽  
...  
Keyword(s):  
Animal Model ◽  
Insulin Secretion ◽  
Insulin Dependent Diabetes Mellitus ◽  
Dependent Diabetes Mellitus ◽  
Factors Affecting ◽  
In Vitro Insulin Secretion ◽  
Insulin Secretion In Vitro ◽  
And Control

The strain of athymic nude male mice (ANM) developed at the University of Southern California (USC) exhibits spontaneous hyperglycemia and relative hypoinsulinemia in vivo. To investigate factors that influence insulin secretion in this animal model of non-insulin-dependent diabetes mellitus, we utilized the isolated perfused mouse pancreas of the ANM-USC and control BALB/c mice. We compared in vitro glucose-induced insulin secretion in ANM-USC and control mice, inhibition of secretion by somatostatin, and variability of insulin secretion over the two-year period it took to complete these experiments. Glucose-induced insulin secretion from the isolated pancreas was biphasic in both ANM-USC and controls. Insulin secretion was quantitatively equal to or greater than control mice, depending on the phase of secretion analyzed and the source of the control mice. In contrast to pancreases of control mice, insulin secretion from ANM-USC pancreases was relatively resistant to inhibition of insulin secretion by somatostatin. Variability in insulin secretion over the two years in which these experiments were performed was greater from pancreases of control than that observed from pancreases of the ANM-USC. The hyperglycemic ANM-USC mouse does not demonstrate diminished insulin secretion in vitro yet is relatively hypoinsulinemic in vivo. Thus circulating factors other than somatostatin might contribute to the insulinopenic stage in this animal model.

Electrocatalytic Glucose Sensor for Long-Term in vivo use

1994 ◽  
Vol 17 (3) ◽  
pp. 183-188 ◽  
Author(s):  
W. Lager ◽  
I. Von Lucadou ◽  
H. Nischik ◽  
T. Nowak ◽  
W. Preidel ◽  
...  
Keyword(s):  
Glucose Concentration ◽  
Glucose Sensor ◽  
Vena Cava ◽  
Insulin Dosage ◽  
Good Biocompatibility ◽  
Materials Used ◽  
Reference Measurements ◽  
And Control

A catheter shaped electrocatalytic glucose sensor for in vivo application has been developed to determine the glucose level in blood and control the insulin dosage in a closed loop system for diabetes therapy. The principle of measurement is based on the electrochemical oxidation of glucose at a membrane-covered platinum electrode. For various potential steps, the impedance obtained at two different frequencies is a function of the glucose concentration. A series of implantations in the vena cava of sheep demonstrated the potential feasibility of the sensor. It was possible to determine the glucose concentration in sheep for more than 130 days with tolerable deviations from glucose reference measurements. The mean error was 2.5 mmol/l. The catheter was explanted after 211 days and histological examination revealed a good biocompatibility of all materials used.

scholarly journals Evaluation of the Biocompatibility of a Recent Bioceramic Root Canal Sealer (BioRoot™ RCS): In-vivo Study

2020 ◽  
Vol 8 (D) ◽  
pp. 100-106
Author(s):  
Laila Hussein El-Mansy ◽  
Magdy Mohamed Ali ◽  
Reham EL Sayed Hassan
Keyword(s):  
Root Canal ◽  
Subcutaneous Tissue ◽  
Tissue Response ◽  
Physical Parameters ◽  
Ah Plus ◽  
Negative Controls ◽  
And Control ◽  
Root Canal Sealers ◽  
Selection Of

BACKGROUND: Recently, new calcium silicate bioceramic sealers were introduced to the market. The selection of root canal sealers should not only be based on the different physical parameters but also on local biocompatibility and tissue tolerance. AIM: This study aimed to evaluate and compare the in-vivo biocompatibility of a BioRoot RCS in parallel to MTA Fillapex and AH Plus sealers. METHODS: Polyethylene tubes containing the freshly mixed test materials were implanted in the subcutaneous tissue of 32 Wistar rats. Empty tubes served as negative controls. After 7, 14, 30, and 60 days, the animals were sacrificed, and the implants with surrounding tissues were processed for routine histological analysis. Histological sections were analyzed under light microscopy. The tissue response was determined by the inflammatory cell infiltration intensity and the fibrous capsule thickness. RESULTS: Results revealed a statistically significant decrease of the inflammation intensity by time within each group for all tested sealers and control. A well-defined thin capsule was observed for all tested sealers at 60 days. CONCLUSION: BioRoot RCS exhibited rapid recovery of inflammation similar to controls. Thus, within the limitations of this study, it can be considered a biocompatible sealer with acceptable tissue tolerance.

An Empirical Analysis of the Government Cloud Adoption in India

2021 ◽  
Vol 17 (3) ◽  
pp. 21-43
Author(s):  
Kshitij Kushagra ◽  
Sanjay Dhingra
Keyword(s):  
Positive Influence ◽  
Key Factors ◽  
Indian Government ◽  
Factors Affecting ◽  
Moderating Variables ◽  
Cloud Adoption ◽  
Government Organizations ◽  
The Government ◽  
Organizational Administration ◽  
And Control

Cloud in the Indian government is still in the nascent stage; the rate of government cloud adoption (GCA) has not been that encouraging. The government organizations are complex, slow, rigidly structured, and research deficient. These organizations are the highest spenders on IT but are not placed at par when it comes to terms of cloud adoption. This empirical study has three objectives, which are identifying the key factors affecting GCA, finding out if these factors significantly affect the adoption, and examining the categorical moderating effect of organization types and adoption stages on GCA. This study posits government organization type (center, state, local bodies, and public sector organizations) and adoption stages (adopted, currently evaluating, and plans to adopt) as moderating variables. PLS-SEM has been deployed in this work for analysis and validation of the model. Nine factors found to have a significant positive influence on GCA are security, connectivity, migration, procurement, awareness, organizational administration, legal, trust, and control.

Sign in / Sign up

Export Citation Format

Share Document