The virus responsible for Middle Eastern respiratory syndrome, MERS-CoV is a lineage C betacoronavirus similar to the mouse hepatitis virus type A59 (MHV-A59). The first reported case of MERS occurred in Saudi Arabia in 2012 and resulted in 76 deaths1. Outbreaks of MERS have since occurred not only in the Middle East but South Korea as well2. Rapid, efficient, and automated methods of disinfecting surfaces contaminated with the MERS-CoV virus may prevent the spread of the virus in the healthcare setting. Here we report on the use of an automated triple-emitter whole room disinfection system to inactivate the MHV-A59 and the MERS-CoV viruses on surfaces with a greater than 5 log10 reduction on MERS in 5 minutes of UV-C exposure.
The mechanisms by which antenatal glucocorticoids facilitate postnatal circulatory function in preterm infants are uncertain but may be related to augmented angiotensinergic functions. To test the hypothesis that the effects of glucocorticoids on postnatal cardiovascular and sympathetic activity are mediated via the renin-angiotensin system, we studied the effects of AT(1) receptor blockade on postnatal changes in heart rate (HR), mean arterial blood pressure (MABP), renal sympathetic nerve activity (RSNA), and baroreflex control of HR in prematurely delivered lambs. After maternal administration of betamethasone (12 mg im 48 and 24 h before delivery), chronically instrumented preterm lambs (118- to 123-day gestation, term 145 days) were studied before and after delivery by cesarean section; fetuses received either the AT(1) receptor antagonist losartan (10 mg iv, n = 6) or saline (n = 6) 1 h before delivery. A third group of animals (n = 6) received losartan without prior exposure to betamethasone. Compared with fetal values, betamethasone-treated animals demonstrated significant increases (P < 0.05) in MABP (47 +/- 2 to 58 +/- 2 mmHg) and RSNA (181 +/- 80% of fetal value) 1 h after delivery. Betamethasone + losartan-treated lambs also displayed increases in MABP (48 +/- 1 to 55 +/- 3 mmHg) and RSNA (198 +/- 96% of fetal value) 60 min after birth, similar to betamethasone alone lambs. Losartan alone treated animals had no postnatal increase in either MABP or RSNA, responses similar to those seen in nontreated sheep delivered at the same gestational age. The sensitivity of baroreflex-mediated changes in HR in response to increases in MABP was less in both groups of betamethasone-treated animals; no effect was seen with losartan. These results suggest the postnatal increases in MABP and RSNA seen with antenatal glucocorticoid treatment are not mediated by stimulation of peripherally accessible AT(1) receptors. We speculate that augmented cardiovascular function in glucocorticoid-treated premature lambs is dependent, in part, on a generalized sympathoexcitatory response and that this effect of glucocorticoids is mediated by central mechanisms.
Numerous metabolic adaptations occur in the heart after birth. Important transcription factors that regulate expression of the glycolytic and mitochondrial oxidative genes are hypoxia-inducible factors (HIF-1alpha and -2alpha) and nuclear respiratory factor-1 (NRF-1). The goal of this study was to examine expression of HIF-1alpha, HIF-2alpha, and NRF-1 and the genes they regulate in pre- and postnatal myocardium. Ovine right and left ventricular myocardium was obtained at four time points: 95 and 140 d gestation (term = 145 d) and 7 d and 8 wk postnatally. Steady-state mRNA and protein levels of HIF-1alpha and NRF-1 and protein levels of HIF-2alpha were measured along with mRNA of HIF-1alpha-regulated genes (aldolase A, alpha- and beta-enolase, lactate dehydrogenase A, liver and muscle phosphofructokinase) and NRF-1-regulated genes (cytochrome c, Va subunit of cytochrome oxidase, and carnitine palmitoyltransferase I ). HIF-1alpha protein was present in fetal myocardium but dropped below detectable levels at 7 d postnatally. HIF-2alpha protein levels were similar at the four time points. Steady-state mRNA levels of alpha-enolase, lactate dehydrogenase A, and liver phosphofructokinase declined significantly postnatally. Aldolase A, beta-enolase, and muscle phosphofructokinase mRNA levels increased postnatally. Steady-state mRNA and protein levels of NRF-1 decreased postnatally in contrast to the postnatal increases in cytochrome c, subunit Va of cytochrome oxidase, and carnitine palmitoyltransferase I mRNA levels. The in vivo postnatal regulation of enzymes encoding glycolytic and mitochondrial enzymes is complex. As transactivation response elements for the genes encoding metabolic enzymes continue to be characterized, studies using the fetal-to-postnatal metabolic transition of the heart will continue to help define the in vivo role of these transcription factors.
We examined the hypothesis that endogenous angiotensin II and angiotensin type 1 (AT1) receptors participate in the development of fetal right ventricular hypertrophy by studying the effects of AT1 receptor blockade on cardiac growth in fetal sheep subjected to constrictive banding of the pulmonary artery (PA). Seven pairs of twin fetuses were studied beginning at 126 ± 1 days gestation (term = 145 days). One twin was given losartan (10 mg ⋅ kg−1 ⋅ day−1iv) for 7 consecutive days after PA banding, and the other twin served as a saline-treated, PA-banded control. Four additional pairs of twins served as sham-operated controls. Fetal heart rate (HR) and mean arterial blood pressure (MABP) were similar in the two groups of PA-banded animals before treatment and remained unchanged in the PA-banded control group. Losartan resulted in a significant decrease ( P < 0.05) in MABP between days 0 and 7, whereas HR was not affected. Total body weight of the losartan-treated animals was significantly less ( P < 0.05) than twin PA-banded controls and nonbanded fetuses. Right ventricle weight-to-body weight ratios were similar in saline (2.29 ± 0.34 g/kg) and losartan-treated (2.11 ± 0.15 g/kg) PA-banded animals and significantly greater than that in nonbanded fetuses (1.52 ± 0.07 g/kg). Similar differences were seen in the right ventricle weight-to-left ventricle weight ratios. Right and left ventricle AT1 receptor mRNA and protein expression were also similar among the three groups, as were AT2 receptor mRNA levels. These data suggest that endogenous angiotensin II does not contribute to the development of pressure overload-induced right ventricular hypertrophy during fetal life and that expression of angiotensin receptors is not altered by increased afterload in the ovine fetus.
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