Designing Calcium Silicate Cements with On-Demand Properties for Precision Endodontics.

Calcium silicate (C3S) cements are available in kits that do not account for patients' specific needs or clinicians' preferences regarding setting time, radiopacity, mechanical, and handling properties. Moreover, slight variations in powder components and liquid content affect cement's properties and bioactivity. Unfortunately, it is virtually impossible to optimize several cement properties simultaneously via the traditional "one variable at a time" strategy, as inputs often induce trade-offs in properties (e.g., a higher water-to-powder ratio [W/P] increases flowability but decreases mechanical properties). Herein, we used Taguchi's methods and genetic algorithms (GAs) to simultaneously analyze the effect of multiple inputs (e.g., powder composition, radiopacifier concentration, and W/P) on setting time, pH, flowability, diametral tensile strength, and radiopacity, as well as prescribe recipes to produce cements with predicted properties. The properties of cements designed with GAs were experimentally tested, and the results matched the predictions. Finally, we show that the cements increased the genetic expression of odonto/osteogenic genes, alkaline phosphatase activity, and mineralization potential of dental pulp stem cells. Hence, GAs can produce cements with tailor-made properties and differentiation potential for personalized endodontic treatment.

3D bioprinting of skin: a state-of-the-art review on modelling, materials, and processes.

The skin is the largest organ of the body, having a complex multi-layered structure and guards the underlying muscles, bones, ligaments, and internal organs. It serves as the first line of defence to any external stimuli, hence it is the most vulnerable to injury and warrants the need for rapid and reliable regeneration methods. Tissue engineered skin substitutes help overcome the limitations of traditional skin treatment methods, in terms of technology, time, and cost. While there is commendable progress in the treating of superficial wounds and injuries with skin substitutes, treatment of full-thickness injuries, especially with third or fourth degree burns, still looks murkier. Engineering multi-layer skin architecture, conforming to the native skin structure is a tougher goal to achieve with the current tissue engineering methods, if not impossible, restoring all the functions of the native skin. The testing of drugs and cosmetics is another area, where engineered skins are very much needed, with bans being imposed on product testing on animals. Given this greater need, 3D bioprinting is a promising technology that can achieve rapid and reliable production of biomimetic cellular skin substitutes, satisfying both clinical and industrial needs. This paper reviews all aspects related to the 3D bioprinting of skin, right from imaging the injury site, 3D model creation, biomaterials that are used and their suitability, types of cells and their functions, actual bioprinting technologies, along with the challenges and future prospects.

AMFR gene silencing inhibits the differentiation of porcine preadipocytes.

Our study clarifies the role of the autocrine motility factor receptor (AMFR) gene in porcine preadipocyte differentiation. AMFR-siRNA was transfected into porcine preadipocytes and the preadipocytes were induced to differentiation. Subsequently, qRT-PCR was conducted to examine changes in mRNA expression of a series of genes in porcine preadipocytes, including AMFR, sterol-regulatory element-binding protein-1a (SREBP1a), SREBP2, insulin-induced gene 1 (Insig1), and Insig2. Expression changes in the mRNA of genes regulating adipocyte differentiation were also analyzed using qRT-PCR, including peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer-binding protein alpha (C/EBPα), and Kruppel-like factor 2 (KLF2). Western blot analysis was conducted to examine the changes in AMFR protein expression in porcine preadipocytes. Additionally, morphological changes in differentiated porcine preadipocytes were examined by oil red O staining, and changes in optical density (OD) values were measured using an ultraviolet spectrophotometer. At 24 h after transfection with AMFR-siRNA, AMFR mRNA expression significantly reduced (P < 0.01), and AMFR protein expression markedly decreased (P < 0.05). The mRNA expression of SREBP1a, SREBP2, Insig1, and C/EBPα was significantly reduced (P < 0.01), whereas the expression of KLF2 mRNA was significantly elevated (P < 0.01). After induction of preadipocyte differentiation, the number of lipid droplets decreased in the AMFR-silenced group, and the OD value markedly reduced (P < 0.05). In addition, the expression of C/EBPα mRNA significantly decreased (P < 0.05), whereas the expression of KLF2 mRNA considerably increased (P < 0.05). Taken together, silencing of the AMFR gene inhibits the differentiation of porcine preadipocytes.

Cloning and prokaryotic expression of the porcine lipasin gene.

Lipasin has recently been demonstrated to be involved in lipid metabolism. In this study, two specific primers were used to amplify the lipasin open reading frame from porcine liver tissue. The polymerase chain reaction product was cloned to a pGEM®-T Easy Vector, digested by SalI and NotI, and sequenced. The lipasin fragment was then cloned to a pET21(b) vector and digested by the same restriction enzyme. The recombinant plasmid was transferred to Escherichia coli (BL21), and the lipasin protein was induced with isopropyl-ß-D-thiogalactopyranoside. The protein obtained was identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis and western blotting. A pET-lipasin prokaryotic recombinant expression vector was successfully constructed, and a 25.2-kDa protein was obtained. This study provides a basis for further research on the biological function of porcine lipasin.

Attenuated mRNA expression of lipid metabolism genes in primary hepatocytes following lipopolysaccharide treatment in dairy cows.

The influence of ruminal acidosis on ruminal microbiology and metabolite production has received considerable attention, but little is known regarding the systemic manifestations that arise from ruminal acidosis. Lipopolysaccharide (LPS) is released in the gastrointestinal tract upon ingestion of high-grain or high-fat diets, and it has been implicated in the etiology of multiple energy- and lipid-related metabolic disturbances in ruminants. The liver plays a crucial role in the acute phase response to intruding pathogens. The effect of blood LPS in subacute ruminal acidosis on lipid metabolism in the liver has not been established. In this study, cell cultures were photographed using an inverted microscope. We observed that hepatocytes changed their morphologies from irregular triangle to circular (contraction) shapes; the number of contracted cells increased with the increasing LPS doses. This suggests that LPS can promote cell contraction and take off the wall, ultimately leading to cell apoptosis. With changes in LPS exposure, hepatocyte number also changes. We explored lipid metabolism in the liver using quantitative reverse transcription-polymerase chain reaction to detect the expression of key lipid metabolism enzymes in hepatocytes. We found that Toll-like receptor 4 signaling pathway mediated by LPS could attenuate mRNA expression of fatty acid synthesis genes and increase the expression of fatty acid transport genes in primary hepatocytes following LPS treatment in dairy cows.

Development and validation of a discretised multi-body spine model in LifeMOD for biodynamic behaviour simulation.

This paper presents a discretised musculoskeletal multi-body spine model using the LifeMOD Biomechanics Modeller. This was obtained by refining spine segments in cervical, thoracic and lumbar regions into individual vertebra segments, using rotational joints representing the intervertebral discs, building various ligaments between vertebrae and implementing necessary lumbar muscles. To validate the model, two comparison studies were made with in vivo intradiscal pressure measurements of the L4-L5 disc as well as extension moments, axial force and shear force around L5-S1 obtained from spine models available in the literature. The results indicated that the present model is in good correlation with both cases and matches well with experimental data which found that the axial forces are in the range of 3929-4688 N and shear forces up to 650 N. This study provides a preliminary overview of our ongoing work towards building bio-fidelity discretised multi-body spine models for investigating various medical applications. These models can be useful for incorporation into design tools for wheelchairs or other seating systems which may require attention to ergonomics as well as assessing biomechanical behaviour between natural spines and spinal arthroplasty or spinal arthrodesis. Furthermore, these models can be combined with haptic-integrated graphic environments to help surgeons to examine kinematic behaviours of scoliotic spines and to propose possible surgical plans before spine correction operations.

Expression of the porcine lipoic acid synthase (LIAS) gene in Escherichia coli.

Lipoic acid synthase, which exists primarily in mitochondria, participates in the biosynthesis of intrinsic lipoic acid. The lipoic acid synthase gene in pig is known as LIAS. To further investigate the biological functions of the protein that is encoded by LIAS, we cloned the open read frame of porcine LIAS (GenBank No. JN797612.1) into the expression vector pET-28α(+). The resulting pET-28α(+)-Lias recombinant vector was introduced into the Escherichia coli BL21 (DE3) strain. With induction by isopropyl ß-D-1-thiogalactopyranoside, the recombinant E. coli strain can express the target protein that has a molecular weight of 41.58 kDa, which was confirmed by Western blotting.

Effects of lipopolysaccharide on the stearoyl-coenzyme A desaturase mRNA level in bovine primary hepatic cells.

This study aimed to compare the effects of lipopolysaccharide (LPS) on stearoyl-coenzyme A desaturase (SCD) gene expression in mouse primary hepatic cells. To obtain sufficient total RNA, primary hepatic cells were plated on 6-cm diameter-type collagen 1-coated dishes (1 x 106 cells per dish). The test was divided into 6 groups with 6 replications per group. The 6 groups were treated with the following volumes of LPS (0.1 mg/mL): 0, 1, 1.5, 2, 4, and 8 µL. The cells were cultured for 24 h, and the total RNA was extracted from samples. Reverse transcription polymerase chain reaction was used to analyze SCD mRNA levels. With increasing LPS amounts, the SCD mRNA expression first decreased and then increased slightly; the expression was the lowest in the 2-µL LPS condition. The SCD mRNA levels from the 4- and 8-µL LPS conditions were slightly higher than that from the 2-µL LPS condition, but the difference was not significant (P > 0.05). The SCD mRNA level from the 2-µL LPS condition was obviously lower than that from the 0-, 1-, and 1.5-µL LPS condition, and the differences were significant (P < 0.05), and the SCD mRNA levels from the 0-, 1-, and 1.5-µL LPS conditions were not significantly different (P > 0.05). The SCD mRNA levels from the 4- and 8-µL LPS conditions were obviously lower than those from the 0- and 1-µL LPS conditions, and the differences were significant (P < 0.05).

Isolation and identification of bovine primary hepatocytes.

The liver is a unique organ that is endowed with a plethora of specialized functions. Most of its functional traits are controlled by hepatocytes. Primary hepatocytes have been used widely in in vitro models to understand the biological processes occurring in the liver. There are a number of methods used to separate hepatocytes, but the cell activity and purity are much lower in this condition. On the basis of previous research, in this study, the two-step collagenase perfusion technique was used for isolating hepatocytes. The key proteins of hepatocytes, cytokeratin-18 (CK-18) and albumin (ALB), were used to identify cells, and their contents were evaluated by immunohistochemistry and Western blotting. The results showed that the isolated hepatocytes comprised more than 96% of the corresponding protein volume stability. Therefore, this method was demonstrated to be reliable for identifying hepatocytes.

Molecular cloning and expression of the porcine S14R gene in Escherichia coli.

We amplified S14R protein gene cDNA of porcine, cloned it into a prokaryotic expression plasmid, and expressed it in Escherichia coli. A pair of primers was designed based on the cDNA sequence of the porcine S14R gene in GenBank. The target gene fragment from porcine liver tissue was amplified by RT-PCR. Confirmed by auto-sequencing, the target gene fragment was subcloned into an expression vector of pET28a. The pET28a-S14R construct was subsequently transformed into E. coli BL21 (DE3). This construct was verified by restriction endonuclease digestion and sequencing. Using isopropyl ß-D-1-thiogalactopyranoside induction, a new recombinant protein with the expected relative molecular mass of 24 kDa appeared. The result was identified by SDS-PAGE electrophoresis. Porcine S14R includes 549bp (GenBank No. JN793537), with an open reading frame of 549 bp coding 182 amino acids.

IL-8 mRNA expression in the mouse mammary glands during pregnancy and lactation.

Interkeukin-8 (IL-8) is an important inflammatory mediator. It is an angiogenic factor associated with inflammation and carcinogenesis. To date, research on IL-8 has been limited to its role as an indicator of inflammation. There has been no systematic research concerning IL-8 expression levels in the mouse mammary gland during pregnancy and lactation. Mouse mammary gland samples were collected on days 1, 6, 12, 18 of pregnancy and of lactation (6 mice per group). The expression levels of IL-8 mRNA were measured by semi-quantitative RT-PCR, with GAPDH as an internal control. IL-8 mRNA was highly expressed on day 1 of pregnancy in the mouse mammary glands (IL-8(IOD)/GAPDH(IOD) = 1.68), and then suddenly declined; it reached 0.74 and 0.71 on days 6 and 12 of pregnancy. On day 18 of pregnancy, it started to increase (IL-8(IOD)/GAPDH(IOD) = 1.02). However, the expression levels of IL-8 mRNA were not significant during pregnancy. During lactation, IL-8 expression level was lower than during pregnancy, but it stabilized at 0.32-0.41 (IL-8(IOD)/GAPDH(IOD)) from day 1 to day 18 of lactation, although the difference was not significant. We suggest that the changes in IL-8 expression level during development is related to its regulatory role in mouse mammary gland immunity.

Leptin mRNA expression in the rat mammary gland at different activation stages.

Leptin is expressed in various tissues, suggesting that this protein is effective not only at the central nervous system level, but also peripherically. Recent studies have shown leptin production by other tissues, including the placenta, stomach, and mammary tissues, but there is no information available concerning expression levels of leptin in the rat mammary gland at different activation stages. We used semi-quantitative RT-PCR to investigate leptin mRNA expression levels in the rat mammary gland at different activity stages. Rat mammary gland samples were collected from virgin females and on days 6, 12, 18 of pregnancy and of lactation (six rats per group). The expression levels of leptin mRNA were measured by semi-quantitative RT-PCR, with ß-actin as an internal control. Leptin mRNA was highly expressed in virgin rat mammary glands (leptin(IOD)/ß-actin(IOD) = 1.60). It decreased gradually during pregnancy, being lowest at 18 days of pregnancy, when the levels were significantly lower than in virgin mammary tissue. Leptin mRNA increased slightly during lactation, but the difference was not significant. By day 18 of lactation, expression levels of leptin mRNA reached the same values as in virgin mammary tissue (leptin(IOD)/ß-actin(IOD) = 1.65). Based on these results, we suggest that leptin has an important regulation role in rat mammary gland activation.

mRNA abundance and expression of SLC27A, ACC, SCD, FADS, LPIN, INSIG, and PPARGC1 gene isoforms in mouse mammary glands during the lactation cycle.

The functions of distinct isoforms of solute carrier family 27 transporters (SLC27A1-6), acetyl-CoA carboxylase (ACACA, ACACB), stearoyl-CoA desaturase (SCD1-4), fatty acid desaturase (FADS1-3), LPIN (LPIN1-3), insulin-induced gene (INSIG1, 2), and peroxisome proliferator-activated receptor gamma coactivator1 (PPARGC1A, B) were studied in the mouse mammary gland from pregnancy to lactation. The relative mRNA abundance and percent change in real-time PCR were determined. mRNA expression of SLC27A3 and SLC27A4 was 37- and 1.4-fold more upregulated at 12 days of lactation, respectively (P < 0.01). Transcripts of SCD isoforms were the most abundant, accounting for 59% of all genes measured, and PPARGC1 isoforms were the least (0.06% of all genes measured). The mRNA abundance from ACC, FADS and LPIN accounted for 29, 9 and 2.6%, respectively. INSIG1 mRNA expression was 32-fold more upregulated (P < 0.05), while PPARGC1B was 0.18-fold downregulated at 18 days of lactation (P < 0.01). We concluded that mRNA abundance and expression of these isoforms are affected by the stage of lactation.

Selection and use of reference genes in mouse mammary glands.

Obtaining quantitative data concerning gene expression is important for understanding milk synthesis in mammary glands. Quantitative real-time PCR (qRT-PCR) is an efficient tool to calculate gene expression; however, it is necessary to find valid reference genes for normalization of qRT-PCR data. We applied the geNorm software to eight commonly used reference genes to identify the most stable and optimal genes for the mouse mammary gland. Based on this analysis, HPRT, RPL and GAPDH are the most appropriate reference genes for data normalization. We tested the expression of the alpha-lactalbumin and fatty acid synthase genes using these three reference genes, both normalized and non-normalized. The normalized mRNA expression ratio was significantly different from the non-normalized ratio. We recommend the use of these three reference genes for the normalization of qRT-PCR data in gene expression studies of mouse mammary glands.

[Analysis of 59 cases of non-traumatic sudden death in various neurological diseases].

Sudden death is a common complication of myocardial infarction, necrotic pancreatitis and other diseases. Physicians usually neglect the possibility of neurological disorders. 59 cases of sudden death among 314 autopsied cases with neurological diseases were analyzed. The most frequent cause of neurological sudden death was cerebrovascular disease (CVD). It was present in 53 (89.9%) cases. 48 of them had hemorrhagic CVD. 37 of these 48 cases were due to hypothalamic lesions. In 37 cases general autopsy was performed; pathological abnormalities of heart, lungs, stomach etc, were found in 28 of them. In conclusion, the size and location of the lesion correlated with the prognosis of the disease. Concomitant multiple organ damage may deteriorate the lesion. Awareness of sudden death resulting from CVD may elevate the rate of correct diagnosis.