Breakdown of Phosphatidylserine Asymmetry Following Treatment of Erythrocytes with Lumefantrine

Background: Lumefantrine, a commonly used antimalarial drug, inhibits hemozoin formation in parasites. Several other antimalarial substances counteract parasitemia by triggering suicidal death or eryptosis of infected erythrocytes. Eryptosis is characterized by cell shrinkage and cell membrane scrambling leading to phosphatidylserine-exposure at the erythrocyte surface. Signaling involved in eryptosis include increase of cytosolic Ca²⁺-activity ([Ca²⁺]_i), formation of ceramide, oxidative stress and/or activation of p38 kinase, protein kinase C (PKC), or caspases. The present study explored, whether lumefantrine stimulates eryptosis. Methods: Cell volume has been estimated from forward scatter, phosphatidylserine-exposure from annexin V binding, [Ca²⁺]_i from Fluo3-fluorescence, reactive oxygen species from 2'',7''-dichlorodihydrofluorescein-diacetate fluorescence, content of reduced glutathione (GSH) from mercury orange fluorescence, and ceramide abundance from binding of fluorescent antibodies in flow cytometry. Results: A 48 h exposure to lumefantrine (3 µg/mL) was followed by a significant increase of annexin-V-binding without significantly altering forward scatter, [Ca²⁺]_i, ROS formation, reduced GSH, or ceramide abundance. The annexin-V-binding following lumefantrine treatment was not significantly modified by p38 kinase inhibitors SB203580 (2 μM) and p38 Inh III (1 μM), PKC inhibitor staurosporine (1 µM) or pancaspase inhibitor zVAD (1 or 10 µM). Conclusions: Lumefantrine triggers cell membrane scrambling, an effect independent from entry of extracellular Ca²⁺, ceramide formation, ROS formation, glutathione content, p38 kinase, PKC or caspases.     

Liver function monitoring in Fontan-procedure patients: audit of current practice across South Wales

The Fontan procedure provides a palliative surgical repair for complex congenital heart disease, but it is associated with many long-term problems, including liver cirrhosis, and hepatocellular carcinoma. The current suggestion from international guidance is that end-organ surveillance should be carried out, with a particular focus on regular blood tests and imaging for liver function.In this study, retrospective analysis was performed on adult patients who had previously had a Fontan operation performed to determine the regularity of end-organ surveillance in regards to their liver function covering the three calendar years from 2016 to 2018, and the first six months of 2019.Eighty-six patients were identified in South Wales monitored by the adult congenital heart disease unit. We found that the number of investigations performed in the first six months of 2019 was comparable to other calendar years in their entirety. Liver function tests had been performed in 57% of patients throughout 2018, with only 8% having had an alpha-fetoprotein taken, and only 9% having had imaging of the liver performed. Over the course of their lifetime, 97% of patients had had a liver function blood test performed at some point, with 17% having had an alpha-fetoprotein taken, and 49% having their liver imaged.In conclusion, end-organ surveillance is an important follow-up for patients with a Fontan circulation, with guidelines proposing yearly blood test and imaging investigations. This study shows the opportunities to improve surveillance in this group of patients to highlight the development of liver cirrhosis, and/or hepatocellular carcinoma.Key words: congenital heart defects, Fontan procedure, healthcare quality assurance, hepatocellular carcinoma, liver disease     

The antigen/receptor specificity of antigranulocyte antibodies in patients with SLE

The antigen/receptor specificity of antigranulocyte antibodies (AGAs) detected in the sera of patients with systemic lupus erythematosus (SLE) was investigated by inhibitory immunofluorescence test and Western immunoblotting technique. The interactions of AGAs with antigens of intact normal granulocytes were determined by inhibiting the binding of different myeloid monoclonal antibodies (mAbs). Seven of the studied 12 sera revealed binding to CD15 (X hapten) and/or to CD16 (FcR1o). The specificity investigation of AGAs was completed with Western immunoblotting technique. The binding of AGAs to bands with Mr of about 50-60 kDa and at 30 kDa on unstimulated granulocyte plasma membrane preparation could be demonstrated from 4 out of 6 AGA positive SLE sera. The cause of the disappearance of bands on the phorbol-myristate-acetate (PMA) activated membrane except those of the 50-60 kDa bands is still to be discovered.     

Early results after minimal lobectomy for benign nodular goiter

Following traditional operations (enucleation and subtotal resection) for benign nodular goiters recurrences may develop. Reoperations for this condition can cause complications, such as hypoparathyroidism and damage of the recurrent laryngeal nerve. That is why total thyroidectomy is recommended by many specialists in benign thyroid disease. We performed lobectomy on one side, and, if necessary, partial resection on the other side. Lobectomy was performed on one side in 31 cases, with partial resections on the other side in 73 patients. We tried to identify the parathyroid glands and both recurrent laryngeal nerves. Postoperative complications were evaluated. Temporary dysfunction of the recurrent laryngeal nerve was detected in 2.3%, permanent damage in 1.1%. Temporary hypocalcaemia developed in 16.4%, permanent hypocalcemia in 1.9%. Two reoperations were necessary for bleeding. Because of the low postoperative complication rate we recommend this method as an alternative to thyroidectomy for benign nodular goiters. We know that our favourable results can be compared with traditional subtotal resection and thyroidectomy when long term results of thyroid function and data about nodular recurrences will be collected.     

Sulfate esters of morphine derivatives: Synthesis and characterization

Sixteen 3-O- and 6-O-sulfate esters of morphine, codeine and some of their N-methyl quaternary derivatives were synthesized by means of sulfation with pyridine–SO₃ complex and sulfuric acid/N,N′-dicyclohexylcarbodiimide. Complete ¹H- and ¹³C-NMR assignments are given for each of the synthesized compounds based on one- and two-dimensional homo- and heteronuclear measurements. Comparative analysis of chiral properties by circular dichroism and optical rotatory dispersion revealed characteristic differences in the spectra due to changes in charge, polarity and intramolecular association by strong hydrogen bonds in aqueous solution. The synthesized sulfate esters are prospective peripheral analgesics lacking central side effects and are also useful as reference substances for various analytical studies involving sulfate ester metabolites.     

Unbinding process of adsorbed proteins under external stress studied by atomic force microscopy spectroscopy

We report the study of the dynamics of the unbinding process under a force load f of adsorbed proteins (fibrinogen) on a solid surface (hydrophilic silica) by means of atomic force microscopy spectroscopy. By varying the loading rate r(f), defined by f = r(f) t, t being the time, we find that, as for specific interactions, the mean rupture force increases with r(f). This unbinding process is analyzed in the framework of the widely used Bell model. The typical dissociation rate at zero force entering in the model lies between 0. 02 and 0.6 s(-1). Each measured rupture is characterized by a force f(0), which appears to be quantized in integer multiples of 180-200 pN.