Embryonic mouse STO cell-derived xenografts express hepatocytic functions in the livers of nonimmunosuppressed adult rats

Cells derived from embryonic mouse STO cell lines differentiate into hepatocytes when transplanted into the livers of nonimmunosuppressed dipeptidylpeptidase IV (DPPIV)-negative F344 rats. Within 1 day after intrasplenic injection, donor cells moved rapidly into the liver and were found in intravascular and perivascular sites; by 1 month, they were intrasinusoidal and also integrated into hepatic plates with approximately 2% efficiency and formed conjoint bile canaliculi. Neither donor cell proliferation nor host inflammatory responses were observed during this time. Detection of intrahepatic mouse COX1 mitochondrial DNA and mouse albumin mRNA in recipient rats indicated survival and differentiation of donor cells for at least 3 months. Mouse COX1 targets were also detected intrahepatically 4-9 weeks after STO cell injection into nonimmunosuppressed wild-type rats. In contrast to STO-transplanted rats, mouse DNA or RNA was not detectable in untreated or mock-transplanted rats or in rats injected with donor cell DNA. In cultured STO donor cells, DPPIV and glucose-6-phosphatase activities were observed in small clusters; in contrast, mouse major histocompatibility complex class I H-2Kq, H-2Dq, and H-2Lq and class II I-Aq markers were undetectable in vitro before or after interferon gamma treatment. Together with H-2K allele typing, which confirmed the Swiss mouse origin of the donor cells, these observations indicate that mouse-derived STO cell lines can differentiate along hepatocytic lineage and engraft into rat liver across major histocompatibility barriers.     

Incorporating platelet-rich plasma into electrospun scaffolds for tissue engineering applications

Platelet-rich plasma (PRP) therapy has seen a recent spike in clinical interest due to the potential that the highly concentrated platelet solutions hold for stimulating tissue repair and regeneration. The aim of this study was to incorporate PRP into a number of electrospun materials to determine how growth factors are eluted from the structures, and what effect the presence of these factors has on enhancing electrospun scaffold bioactivity. PRP underwent a freeze-thaw-freeze process to lyse platelets, followed by lyophilization to create a powdered preparation rich in growth factors (PRGF), which was subsequently added to the electrospinning process. Release of protein from scaffolds over time was quantified, along with the quantification of human macrophage and adipose-derived stem cell (ADSC) chemotaxis and proliferation. Protein assays demonstrated a sustained release of protein from PRGF-containing scaffolds at up to 35 days in culture. Scaffold bioactivity was enhanced as ADSCs demonstrated increased proliferation in the presence of PRGF, whereas macrophages demonstrated increased chemotaxis to PRGF. In conclusion, the work performed in this study demonstrated that the incorporation of PRGF into electrospun structures has a significant positive influence on the bioactivity of the scaffolds, and may prove beneficial in a number of tissue engineering applications.     

Restoration of sagittal and transverse plane proprioception following anatomic double-bundle ACL reconstruction

Purpose

To investigate the restoration of knee proprioception after anatomic double-bundle ACL reconstruction.

Methods

Eleven subjects who underwent anatomic double-bundle ACL reconstruction (12.5–15 months following surgery) and eleven healthy control subjects participated in the study. Sagittal and transverse plane threshold to detect passive motion (TTDPM) were assessed utilizing a customized isokinetic dynamometer by passively rotating the tibia about a fixed femur in both the sagittal plane and transverse plane at 0.25°/s until the subject signalled recognition of movement and movement direction. Based on the normality assumption, either dependent t test or Wilcoxon test was utilized to determine whether significant differences were present between the ACL-reconstructed and the uninjured contralateral limbs. Independent t test or Mann–Whitney test was utilized to compare between the ACL-reconstructed/uninjured contralateral and the external control limbs.

Results

There were no significant differences in TTDPM measurement in eleven out of twelve comparisons between the ACL-reconstructed and the uninjured contralateral/external control limbs. The only statistical significant difference was found on TTDPM towards internal rotation direction from the externally rotated-test position between the ACL-reconstructed and the uninjured contralateral limbs (p = 0.01).

Conclusions

Based on a small sample of eleven subjects, the current results indicate a restoration of both sagittal and transverse plane TTDPM following the anatomic double-bundle ACL reconstruction.

Level of evidence

III.     

Ultrasound-guided internal jugular venous cannulation in infants: a prospective comparison with the traditional palpation method.

BACKGROUND: Percutaneous cannulation of the internal jugular vein in infants is technically more difficult and carries a higher risk of carotid artery puncture than in older children and adults. In this prospective study, the authors tested their hypothesis that using an ultrasound scanner would increase the success of internal jugular cannulation and decrease the incidence of carotid artery puncture in infants. METHODS: After approval from the institutional review board and receipt of written informed parental consent, 95 infants scheduled for cardiac surgery were randomized prospectively into two groups. In the landmarks group, the patients' internal jugular veins were cannulated using the traditional method of palpation of carotid pulsation and identification of other anatomic landmarks. In the ultrasound group, cannulation was guided using an ultrasound scanner image. The cannulation time, number of attempts, success rate, and incidence of complications were compared for the two groups. RESULTS: There were no significant differences between the two groups with regard to weight, age, and American Society of Anesthesiologists physical status classification. The success rate was 100% in the ultrasound group, with no carotid artery punctures, and 77% in the landmarks group, with a 25% incidence of carotid artery punctures. Both differences were significant (P > 0.0004). The cannulation time was less, the number of attempts was fewer, and the failure rate was significantly lower in the ultrasound group than in the landmark group. CONCLUSION: Ultrasonographic localization of the internal jugular vein was superior to the landmarks technique in terms of overall success, speed, and decreased incidence of carotid artery puncture.