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α1-adrenergic Receptor Attenuates β1-adrenergic Modulation of IKr by Protein Kinase C-dependent Suppression of Adenylyl Cyclase in Ventricular Myocytes
Sen Wang,
Xiaoyan Wang,
Jin Qian,
Di Xu
Issue:
Volume 5, Issue 2, March 2019
Pages:
26-32
Received:
8 May 2019
Accepted:
10 June 2019
Published:
25 June 2019
Abstract: The rapid delayed rectifier K+ current (Ikr) is critical for repolarization of the cardiac action potential. Previous studies have shown activated α1-adrenergic receptor (AR) attenuates β1-adrenergic regulation of Ikr while the mechanisms involved are poorly understood. To evalutate how α1-adrenergic receptor affect β1-adrenergic modulation of Ikr, whole-cell patch-clamp recordings were peformed in isolated guinea-pig ventricular myocytes. Application of xamoterol, a selective β1-AR agonist, induced a negative shift in the activation curve and Ikr current reduction by 40.50±6.66% at the test pulse of +40 mV. Forskolin and 8-Br-cAMP also resulted in Ikr reduction by 38.17±1.50% and 24.65±3.37%, respectively. Phenylephrine, a selective α1-AR agonist, prevented the activation shift and Ikr current reduction induced by xamoterol and forskolin, but not by 8-Br-cAMP. The effect of xamoterol or forskolin on Ikr was also prevented by pretreatment with PDBu, a protein kinase C (PKC) activator, while the effect of cAMP on Ikr can not, which was similar to pretreatment with phenylephrine. When cells were pretreated with chelerythrine, a specific PKC inhibitor, phenylephrine failed to prevent Ikr reduction induced by xamoterol. Our data suggests that α1-adrenergic stimulation attenuates β1-adrenergic regulation of Ikr, through PKC-dependent downregulation of adenylyl cyclase/cyclic AMP pathway.
Abstract: The rapid delayed rectifier K+ current (Ikr) is critical for repolarization of the cardiac action potential. Previous studies have shown activated α1-adrenergic receptor (AR) attenuates β1-adrenergic regulation of Ikr while the mechanisms involved are poorly understood. To evalutate how α1-adrenergic receptor affect β1-adrenergic modulation of Ikr,...
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Impact of Laboratory Diagnostic Preanalytics on Patient Blood Management
Kathrin Schlatterer,
Kathrin Schlüter
Issue:
Volume 5, Issue 2, March 2019
Pages:
33-40
Received:
14 March 2019
Accepted:
15 May 2019
Published:
29 June 2019
Abstract: This study was designed to investigate the possibility of reducing diagnostic blood loss as a lab-side element of Patient Blood Management. To this end, the nominal blood volume of blood collection tubes was reduced and, additionally, preanalytical processes were optimised to minimise repeated blood collections. These interventions were conducted in conjunction with a change of blood collection system. Auditing the preanalytical phase and observing sample quality before and after the interventions enabled the assessment of changes in preanalytical quality. The occurrence of several blood collection non-compliances had decreased substantially one year after preanalytical training and conversion to the different blood collection system. Improvement of preanalytical quality combined with reduction of tube blood volumes led to a significant decrease in the volume of blood drawn for diagnostic purposes, corresponding to a reduction of 177 L per year for the whole hospital. We also observed a reduction in the total number of blood collection tubes used. An analysis of data for geriatric and Intensive Care Unit (ICU) ward types, where there is a known risk of iatrogenic anaemia, revealed significant blood savings. In conclusion, targeted preanalytical training measures and introduction of blood collection tubes with lower draw volumes enable significant reductions in the volume of patient blood drawn for laboratory diagnostics, and so represent an important contributor to patient blood management.
Abstract: This study was designed to investigate the possibility of reducing diagnostic blood loss as a lab-side element of Patient Blood Management. To this end, the nominal blood volume of blood collection tubes was reduced and, additionally, preanalytical processes were optimised to minimise repeated blood collections. These interventions were conducted i...
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Morphological Peculiarities of Apoptosis’ Course in Hepatic Cells
Asomiddin Faizovich Sadriddinov,
Khushvakt Beknazarov Joraevich,
Muborak Asomidinovna Sadriddinova,
Elena Nikolaevna Guzacheva
Issue:
Volume 5, Issue 2, March 2019
Pages:
41-45
Received:
19 March 2019
Accepted:
16 May 2019
Published:
12 July 2019
Abstract: The course dynamics of apoptosis in hepatic cells of experimental rabbits (n = 16) and white rats (n = 18) was researched by morphological methods. In natural death (apoptosis) the hepatic cells were divided into two parts. At the first type of apoptosis the hepatocyte’s cytoplasm became clearing, the little vesicles occurred, therefore this type was called as “boiling cytoplasm”. It was more often in rats. The volume of cell increased and became round, the nucleus got peaknotized, and, finally, the apoptotic bodies became formed and eliminated in sinusoids. The second type of apoptosis was characterized with homogenization and acidophilic colour of cytoplasm, the cellular nucleus was decomposed into large conglomerations and kariorexis occurred, so it was marked as “nuclear catastrophe”. At the end of both types the hepatocyte cellular membrane got ruptured, and cytoplasm’s content separated in lumen of vessel. Sometimes old, not being undergone to apoptosis “longliving” hepatocytes became separated from hepatic plates and wholly extrused in lumen of sinusoid. Conclusion: by the cytological course, depending on mainly damage of hepatocyte’ cytoplasm or nucleus two types of apoptosis were divided. Except apoptic death in the liver the extrusion display of “longliving” hepatocytes were revealed.
Abstract: The course dynamics of apoptosis in hepatic cells of experimental rabbits (n = 16) and white rats (n = 18) was researched by morphological methods. In natural death (apoptosis) the hepatic cells were divided into two parts. At the first type of apoptosis the hepatocyte’s cytoplasm became clearing, the little vesicles occurred, therefore this type w...
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