Home-based isometric exercise training induced reductions resting blood pressure

Purpose: Isometric exercise training (IET) reduces resting blood pressure (BP). Most previous protocols impose exercise barriers which undermine its effectiveness as a potential physical therapy for altering BP. An inexpensive, home-based programme would promote IET as a valuable tool in the fight against hypertension. The aims of this study were: (a) to investigate whether home-based wall squat training could successfully reduce resting BP, and (b) to explore the physiological variables that might mediate a change in resting BP. Methods: Twenty-eight healthy normotensive males were randomly assigned to a control and a 4 week home-based IET intervention using a crossover design with a 4 week ‘washout’ period in-between. Wall squat training was completed 3x weekly over 4 weeks with 48 hours between sessions. Each session comprised 4x 2 minute bouts of wall squat exercise performed at a participant-specific knee joint angle relative to a target HR of 95% HRpeak, with 2 minutes rest between bouts. Resting heart rate, BP, cardiac output, total peripheral resistance and stroke volume were taken at baseline and post each condition. Results: Resting BP (systolic = -4 ± 5, diastolic = -3 ± 3 and mean arterial = -3 ± 3 mmHg), cardiac output (-0.54 ± 0.66 L∙min-1) and heart rate (-5 ± 7 beats∙min-1) were all reduced following IET, with no change in total peripheral resistance or stroke volume compared to the control. Conclusion: These findings suggest the wall squat provides an effective method for reducing resting BP in the home resulting primarily from a reduction in resting heart rate

Aneuploidy in pluripotent stem cells and implications for cancerous transformation

Owing to a unique set of attributes, human pluripotent stem cells (hPSCs) have emerged as a promising cell source for regenerative medicine, disease modeling and drug discovery. Assurance of genetic stability over long term maintenance of hPSCs is pivotal in this endeavor, but hPSCs can adapt to life in culture by acquiring non-random genetic changes that render them more robust and easier to grow. In separate studies between 12.5% and 34% of hPSC lines were found to acquire chromosome abnormalities over time, with the incidence increasing with passage number. The predominant genetic changes found in hPSC lines involve changes in chromosome number and structure (particularly of chromosomes 1, 12, 17 and 20), reminiscent of the changes observed in cancer cells. In this review, we summarize current knowledge on the causes and consequences of aneuploidy in hPSCs and highlight the potential links with genetic changes observed in human cancers and early embryos. We point to the need for comprehensive characterization of mechanisms underpinning both the acquisition of chromosomal abnormalities and selection pressures, which allow mutations to persist in hPSC cultures. Elucidation of these mechanisms will help to design culture conditions that minimize the appearance of aneuploid hPSCs. Moreover, aneuploidy in hPSCs may provide a unique platform to analyse the driving forces behind the genome evolution that may eventually lead to cancerous transformation

In vitro regulation of luteal function in mares

Dispersed equine luteal cells collected during dioestrus (days 7-10), before (days 30-35 of pregnancy) and after (days 40-45 of pregnancy) the onset of equine chorionic gonadotropin (eCG) secretion were incubated in defined medium for 24 h to determine steroid production at these specific stages of the reproductive cycle. Luteal cells collected at these three reproductive stages were also incubated for 4 h in defined medium with increasing amounts of eLH, eCG and hCG added to determine the effect of gonadotropins on luteal progesterone and oestrogen production. Progesterone and oestrogen accumulation proceeded in a linear fashion during the 24-h incubation. No differences in rate of progesterone accumulation were observed between the three reproductive stages. A significant effect of reproductive stage on rate of oestrogen accumulation was observed, with oestrogen production being greatest in luteal cells from pregnant mares after the onset of eCG secretion and lowest in luteal cells from mares in dioestrus. Addition of gonadotropin to the medium resulted in a dose-dependent increase in progesterone accumulation during a 4-h incubation at most reproductive stages. However, a significant increase in progesterone accumulation was only observed at supraphysiological concentrations of gonadotropins. Addition of gonadotropin did not result in a change in oestrogen accumulation. The results of this study demonstrate that luteal oestrogen secretion increases with pregnancy and is highest during eCG secretion. These experiments did not demonstrate an effect of gonadotropin on luteal oestrogen secretion in vitro even though an effect on luteal progesterone secretion was observed. The lack of a gonadotropin-induced increase in oestrogen secretion is most likely due to the short duration of the incubation