Activation marker expression and apoptotic susceptibility of T-cell clones derived from CD34(+), young and SENIEUR donors

T-cell clones (TCC) derived from human peripheral blood lymphocytes of a young control, a healthy elderly (SENIEUR) donor, or from CD34(+) hematopoietic progenitor cells were utilised in this study to examine how in vivo and in vitro ageing affects T-cell apoptotic capability. The role of CD25, CD28 and the intracellular proteins, FLICE-inhibitory protein (FLIP), receptor-interacting protein (RIP) and caspase 3 were investigated. We observed an age-related decline in the expression of the IL-2 receptor alpha chain CD25, and absence of the co-stimulatory receptor CD28 on three of the four TCC studied. In young donor- and CD34 cell-derived TCC, but not in SENIEUR donor-derived TCC, we observed an age-related increase in susceptibility of the cells to mFas-L-induced apoptosis, which correlated with the age-related decrease of CD25 expression. Expression levels of full-length RIP and FLIP did not show any correlation to apoptotic susceptibility. However, expression levels of the cleaved form of RIP were greatly reduced in the SENIEUR donor-derived TCC, which together with a trend towards increased caspase 3 activity, could indicate an age-related alteration in utilisation of different apoptotic signalling pathways.     

Adiposity is related to gender differences in impaired stress-induced pressure natriuresis

The purpose of this study was to determine if there are gender differences in stress-induced pressure natriuresis and to examine the effects of adiposity on these differences. The subjects were 151 boys and 141 girls 15 to 18 years of age who underwent a 5-hour stress protocol (2-hour prestress, 1-hour stress, 2-hour poststress) after being brought into similar levels of sodium balance. The gender-by-condition interaction was significant for systolic and diastolic blood pressure (P=0.001 for both), and the effect of condition was significant for sodium excretion (P=0.001). Systolic blood pressure was higher for boys throughout the protocol (P=0.001 for each) and correlated with body mass index at each condition (range in r=0.28 to 0.35; P<0.001 for each). Hemodynamically, in boys body mass index was correlated with cardiac output during stress (r=0.23; P=0.006), which was correlated with systolic blood pressure (r=0.21; P=0.01). With respect to natriuresis, body mass index was inversely correlated with sodium excretion during stress (r=-0.22; P=0.008) and positively correlated with angiotensin II in a subsample of boys (n=89: r=0.31; P=0.003). The inverse correlation between angiotensin II and sodium excretion during stress approached significance (r=-0.17; P<0.06). Similar results were not observed for girls. In conclusion, gender differences in stress-induced pressure natriuresis appear to be related to the influence of adiposity on both blood pressure and natriuresis.     

Likelihood of residential aged care use in later life: a simple approach to estimation with international comparison

Objectives: In New Zealand (NZ), place of death among decedents aged 65+ years has been reported as residential aged care (RAC, 38%), acute hospital (34%) or elsewhere (28%). However, lifetime risk of use of RAC (or nursing homes) is unknown. A simple method of estimation is demonstrated for NZ and Australia, with comparisons to other countries. Methods: Deaths of RAC residents in acute hospitals were estimated for NZ from four separate studies and added to deaths occurring in RAC, to derive the likelihood of using RAC after age 65 years. Academic and other sources were searched for comparative reports. Results: An estimated 18% of RAC residents died in acute hospital in NZ. When added to those who died in RAC, the proportion using RAC for late‐life care was estimated at over 47% (66% if aged 85+ years). Of 12 US reports, the median report was 41%. Elsewhere, Finland was 47%, UK 28%, Australia 34% to 53%, and Germany 22% & 26%. Conclusions: Simple estimation using existing data demonstrates that RAC in late life is common. Implications: Late‐life care services will continue to evolve. Monitoring RAC utilisation is necessary for informed debate about palliative care provision in RAC, use of hospital by RAC residents and for planning and policy setting.     

Cardiac Tamponade,Sever Hypothyroidism and Acute Respiratory Distress Syndrome (ARDS) with COVID-19 Infection

A 21-years-old with Down syndrome presented with respiratory distress. Initial investigations revealed a cardiac tamponade. On further evaluation, he had positive coronavirus disease-2019 (COVID-19), severe chest infection and severe hypothyroidism. He responded well to urgent pericardiocentesis, levothyroxine, hydrocortisone and tocilizumab.     

Effects of beta 1-selective and nonselective beta-adrenoceptor blockade during exercise conditioning in healthy adults

The interaction of beta 1-selective (cardioselective) and nonselective beta-adrenoceptor blockade with exercise conditioning was investigated in 30 healthy adult persons. A double-blind protocol was used and the effects of atenolol (100 mg/day), propranolol (80 mg twice daily), and placebo were studied by treadmill testing (Bruce protocol) before and after a 2-month supervised program of dynamic exercise. Exercise tolerance was assessed by time and work performed to exhaustion. Subjects who received propranolol, but not those who received atenolol or placebo, showed an acutely impaired exercise tolerance after drug administration but before training (-8 +/- 4%, p less than 0.05). All 3 groups showed significantly improved exercise capacity following training after drug treatment had been discontinued (atenolol, 22 +/- 6% improvement; propranolol, 13 +/- 6%; placebo, 10 +/- 3%). However, when tested while still receiving medication, subjects who received propranolol failed to show significant improvement in exercise capacity. In contrast, patients who received atenolol and placebo improved significantly. The data indicate that enhancement of maximal work capacity by exercise conditioning can occur despite administration of either beta 1-selective or nonselective beta-adrenoceptor antagonists. However, the fatiguing effects of propranolol that were evident when work performance during propranolol therapy was compared with work performance while not receiving propranolol before the training program persists after training and may limit the net improvement in work capacity induced by exercise conditioning compared with the pretraining state.     

Mechanism of decongestant activity of alpha 2-adrenoceptor agonists

The vascular bed in nasal mucosa of different species, including human, is highly vascularized and an extensive sinusoidal network of large capacitance vessels is present deep within the submucosa. When this network of venous sinusoids is engorged with blood, the swollen mucosa reduces the size of the airway lumen and congestion ensues. Nasal vasculature tone is strongly influenced by the sympathetic nervous system and the only drugs approved specifically to relieve vascular nasal obstruction are alpha-adrenoceptor sympathomimetic agents. Due to their vasoconstrictor action, the sympathomimetic decongestants oppose vasodilation, reducing nasal airway resistance and thus facilitating nose breathing. However, standard decongestants that are non-selective alpha-adrenoceptor agonists are associated with the potential for side-effect liabilities including hypertension, stroke, insomnia and nervousness. We propose than a selective alpha 2-adrenoceptor agonist, by acting preferentially on nasal venous capacitance vessels, will elicit decongestion with a reduced side-effect liability. In the present study, we evaluated the effects of the selective alpha 2-adrenoceptor agonist BHT-920 in a real-time tissue contractility assay using isolated pig nasal explants and in an in vivo cat model of congestion. The vasoconstrictor and decongestant effects of BHT-920 were compared to the non-selective alpha-adrenoceptor agonist epinephrine and the standard decongestant oxymetazoline. Our results showed that the alpha 2-adrenoceptor agonist BHT-920 preferentially contracts venous sinusoids confirming previous observations [Corboz MR, Varty LM, Rivelli MA, Mutter JC, Mingo G, McLeod R, et al. Effects of an alpha 2-adrenoceptor agonist in nasal mucosa. Arch Physiol Biochem 2003;11: 335-6, Corboz MR, Rivelli MA, Varty LM, Mutter J, Cartwright M, Rizzo CA, et al. Pharmacological characterization of postjunctional alpha-adrenoceptor in human nasal mucosa. Am J Rhinol 2005;19: 495-502] and displays decongestion without affecting blood pressure. Therefore, an alpha 2-adrenoceptor agonist, by causing constriction in the capacitance vessels of nasal mucosa, can produce nasal decongestion without the effects on blood pressure observed with the standard selective alpha 1-adrenoceptor and non-selective alpha-adrenoceptor sympathomimetic decongestants.     

Identification of an oncogenic form of the thrombopoietin receptor MPL using retrovirus-mediated gene transfer

Thrombopoietin and its receptor (MPL) are important regulators of megakaryopoiesis. We have identified an activating mutation of MPL using a combination of a retrovirus-mediated gene transfer and polymerase chain reaction-driven random mutagenesis. This point mutation causes a single amino acid substitution from Ser498 to Asn498 in the transmembrane region and abrogates factor-dependency of all interleukin-3-dependent cell lines tested. Murine interleukin-3- dependent Ba/F3 cells expressing the mutated but not the normal form of MPL were tumorigenic when transduced into syngeneic mice. Analysis of intracellular signaling pathways indicated that the mutant MPL protein constitutively activated two distinct signaling pathways, SHC-Raf-MAPK and JAK2-STAT3/STAT5.