Finite Element Analysis of a Rib Cage Model: Influence of Four Variables on Fatigue Life during Simulated Manual CPR.

Cardiopulmonary resuscitation (CPR) is a life-saving technique used in emergencies when the heart stops beating, typically involving chest compressions and ventilation. Current adult CPR guidelines do not differentiate based on age beyond infancy and childhood. This oversight increases the risk of fatigue fractures in the elderly due to decreased bone density and changes in thoracic structure. Therefore, this study aimed to investigate the correlation and impact of factors influencing rib fatigue fractures for safer out-of-hospital manual cardiopulmonary resuscitation (OHMCPR) application. Using the finite element analysis (FEA) method, we performed fatigue analysis on rib cage models incorporating chest compression conditions and age-specific trabecular bone properties. Fatigue life analyses were conducted on three age-specific rib cage models, each differentiated by trabecular bone properties, to determine the influence of four explanatory variables (the properties of the trabecular bone (a surrogate for the age of the subject), the site of application of the compression force on the breastbone, the magnitude of applied compression force, and the rate of application of the compression force) on the fatigue life of the model. Additionally, considering the complex interaction of chest compression conditions during actual CPR, we aimed to predict rib fatigue fractures under conditions simulating real-life scenarios by analyzing the sensitivity and interrelation of chest compression conditions on the model's fatigue life. Time constraints led to the selection of optimal analysis conditions through the use of design of experiments (DOE), specifically orthogonal array testing, followed by the construction of a deep learning-based metamodel. The predicted fatigue life values of the rib cage model, obtained from the metamodel, showed the influence of the four explanatory variables on fatigue life. These results may be used to devise safer CPR guidelines, particularly for the elderly at a high risk of acute cardiac arrest, safeguarding against potential complications like fatigue fractures.

Postthaw survival of in vitro-produced bovine blastocysts loaded onto the inner surface of a plastic vitrification straw.

In this study, we investigated whether vitrification of an embryo by attachment to the inner surface of a plastic straw, which requires a small volume of vitrification solution, improves the survival of thawed embryos. In vitro-produced Korean native cattle blastocysts were randomly assigned into four groups: (1) blastocysts attached to the inner surface of a plastic straw (aV); (2) blastocysts loaded into the column of a plastic straw (cV); (3) blastocysts directly dropped into liquid nitrogen (dV); and (4) nonvitrified blastocysts (control). The postthaw recovery rate did not significantly differ among the aV, dV, and cV groups (98.3% vs. 81.5% vs. 91.4%). The postthaw survival rate was greater in the control, aV, and dV groups than in the cV group (100%, 87.7%, and 81.8% vs. 26.4%, P < 0.05), but did not significantly differ among the control, aV, and dV groups. The total number of cells per blastocyst did not significantly differ among the groups (134.4 ± 38.9 in control vs. 114 ± 48.1 in aV, 105.6 ± 33.9 in dV, and 102 ± 35.1 in cV group). However, the number of apoptotic cells per blastocyst was higher in the dV and cV groups than in the control group (10.9 ± 9.6 and 14.5 ± 9.5 vs. 0.4 ± 1.4; P < 0.05), but did not significantly differ between the control and aV groups (0.4 ± 1.4 vs. 6.6 ± 9.5). In addition, the blastocoel of each blastocyst was left intact or was mechanically punctured to reduce its volume, and the blastocysts were then vitrified using the aV method. At 12 hours after thawing, the re-expansion rate did not significantly differ among the control, punctured aV, and nonpunctured aV groups (93.3% vs. 85.2% vs. 82.8%). However, at 24 hours after thawing, the hatching rate was greater in the control and punctured aV groups than in the nonpunctured aV group (75% and 62.9% vs. 37.1%; P < 0.05). The total number of cells per blastocyst was greater in the control group than in the nonpunctured aV group (143 ± 37.2 vs. 94.5 ± 18.6; P < 0.05), but did not significantly differ between the control and punctured aV groups (143 ± 37.2 vs. 119.4 ± 19.7). The number of apoptotic cells per blastocyst was greater in the nonpunctured aV group than in the control and punctured aV groups (11.3 ± 6.1 vs. 5.9 ± 5.8 and 6.3 ± 4.4; P < 0.05). Taken together, the data show that the aV method improved the survival and quality of vitrified-thawed blastocysts. Furthermore, puncture of the blastocoel increased the hatching rate and reduced the number of apoptotic cells in vitrified-thawed blastocysts generated using the aV method.

Transgenic chicken, mice, cattle, and pig embryos by somatic cell nuclear transfer into pig oocytes.

This study explored the possibility of producing transgenic cloned embryos by interspecies somatic cell nuclear transfer (iSCNT) of cattle, mice, and chicken donor cells into enucleated pig oocytes. Enhanced green florescent protein (EGFP)-expressing donor cells were used for the nuclear transfer. Results showed that the occurrence of first cleavage did not differ significantly when pig, cattle, mice, or chicken cells were used as donor nuclei (p>0.05). However, the rate of blastocyst formation was significantly higher in pig (14.9±2.1%; p<0.05) SCNT embryos than in cattle (6.3±2.5%), mice (4.2±1.4%), or chicken (5.1±2.4%) iSCNT embryos. The iSCNT embryos also contained a significantly less number of cells per blastocyst than those of SCNT pig embryos (p<0.05). All (100%) iSCNT embryos expressed the EGFP gene, as evidenced by the green florescence under ultraviolet (UV) illumination. Microinjection of purified mitochondria from cattle somatic cells into pig oocytes did not have any adverse effect on their postfertilization in vitro development and embryo quality (p>0.05). Moreover, NCSU23 medium, which was designed for in vitro culture of pig embryos, was able to support the in vitro development of cattle, mice, and chicken iSCNT embryos up to the blastocyst stage. Taken together, these data suggest that enucleated pig oocytes may be used as a universal cytoplast for production of transgenic cattle, mice, and chicken embryos by iSCNT. Furthermore, xenogenic transfer of mitochondria to the recipient cytoplast may not be the cause for poor embryonic development of cattle-pig iSCNT embryos.

Production of transgenic Korean native cattle expressing enhanced green fluorescent protein using a FIV-based lentiviral vector injected into MII oocytes.

The potential benefits of generating and using transgenic cattle range from improvements in agriculture to the production of large quantities of pharmaceutically relevant proteins. Previous studies have attempted to produce transgenic cattle and other livestock by pronuclear injection and somatic cell nuclear transfer, but these approaches have been largely ineffective; however, a third approach, lentivirus-mediated transgenesis, has successfully produced transgenic livestock. In this study, we generated transgenic (TG) Korean native cattle using perivitelline space injection of viral vectors, which expressed enhanced green fluorescent protein (EGFP) systemically. Two different types of lentiviral vectors derived from feline immunodeficiency virus (FIV) and human immunodeficiency virus (HIV) carrying EGFP were injected into the perivitelline space of MII oocytes. EGFP expression at 8-cell stage was significantly higher in the FIV group compared to the HIV group (47.5%±2.2% v.s. 22.9%±2.9%). Eight-cell embryos that expressed EGFP were cultured into blastocysts and then transferred into 40 heifers. Ten heifers were successfully impregnated and delivered 10 healthy calves. All of these calves expressed EGFP as detected by in vivo imaging, PCR and Southern blotting. In addition, we established an EGFP-expressing cell line from TG calves, which was followed by nuclear transfer (NT). Recloned 8-cell embryos also expressed EGFP, and there were no differences in the rates of fusion, cleavage and development between cells derived from TG and non-TG calves, which were subsequently used for NT. These results illustrate that FIV-based lentiviruses are useful for the production of TG cattle. Moreover, our established EGFP cell line can be used for additional studies that involve induced pluripotent stem cells.