Search

As the carbohydrate lacto-N-fucopentaose III (CD 15 antigen or X-determinant) and its sialylated derivative sialyl-Lewis X are involved in the adhesion of cells rolling along the surface of endothelial cells, experiments were done to study the presence of these molecules on human eosinophils from patients with the idiopathic hypereosinophilic syndrome. Normal-density eosinophils from some patients showed higher levels of expression for lacto-N-fucopentaose Ill than light-density eosinophils. In contrast, sialyl-Lewis X was highly expressed by fight-density eosinophils. Activation of normal-density eosinophils with calcium ionophore A23187 resulted in increased expression of these molecules for a short time. Monoclonal antibodies to these carbohydrates stimulated eosinophils to secrete eosinophil cationic protein, but not eosinophil peroxidase, and acted as costimulatory signals for C3b-induced degranulation of eosinophil cationic protein. It was suggested that CD15 and sialyl-Lewis X might contribute to eosinophil-mediated tissue injury in patients with the idiopathic hypereosinophilic syndrome. [ABSTRACT FROM AUTHOR]

Human vascular endothelial cells were isolated by collagenase digestion of umbilical veins. Hybridomas secreting monoclonal antibodies were raised by fusing a mouse myeloma cell line to spleen cells from mice immunized with the isolated endothelial cells. A clone was selected which produced an antibody binding strongly to human umbilical vein endothelial cells. This antibody, EN 3, was shown to be directed against a major antigen on the surface of the cells, and appeared to be distinct from other antigens previously described on vascular tissues. The antibody bound to a lesser extent to umbilical artery endothelial cells and syncytiotrophoblast. Capillary endothelial cells in adult oesophageal tissues and tonsil were also labelled by the antibody, as were capillaries in a seminoma and infiltrating duct carcinoma of the breast. This well defined distribution in some foetal, adult and malignant tissues suggests that there is structural heterogeneity amongst endothelial cells in different sites, which may be linked to differences in differentiation or function. [ABSTRACT FROM AUTHOR]

Patients with the idiopathic hypereosinophilic syndrome (HES) may develop associated skin disorders. We describe a patient who had xerosis since birth, but who first developed symptoms of aquagenic pruritus soon after he presented with HES. Photochemotherapy with psoralen and UVA treatment reduced his peripheral blood eosinophil count. The good response to treatment suggests that there was a close relationship between the dermatosis and the blood disorder. [ABSTRACT FROM AUTHOR]

Intracutaneous testing and patch tests with house dust mite and grass pollen allergens were performed in patients with atopic dermatitis. Only patients with an immediate type skin reaction to house dust mite or grass pollen allergens showed a positive patch test reaction to these allergens 24-48 h after testing. Occasionally positive patch test reactions at 20 mm, 2 h and 6 h were also observed. Patch test reactions were not found in normal controls or atopic patients without atopic dermatitis. Analysis of the cellular infiltrate demonstrated an influx of eosinophils into the dermis, starting from 2-6 h after patch testing. Immunostaining with antibodies against granular constituents of the eosinophils revealed that the infiltrating eosinophils were in an activated state and had lost part of their granular contents. At 24 h eosinophils also appeared in the epidermis. Electron microscopy showed that in the epidermis, some eosinophils were in close contact with Langerhans cells, suggesting a cell-cell interaction. Taken together, these results strongly suggest an active role for eosinophils in patch test reactions to inhalant allergens in atopic dermatitis patients. [ABSTRACT FROM AUTHOR]

The article focuses on important advances in the immunology and molecular biology of schistosomiasis discussed at the meeting of the Section of Clinical Immunology & Allergy on June 10, 1985. Speakers during the meeting include physicians Paul Hagan and Anthony Butterworth. The demonstration of acquired resistance to reinfection by patients exposed to Shistosoma mansoni and Shistosoma haematobium and protective immunity are also addressed.

Information about the reports made at the meeting of the Section of Clinical Immunology & Allergy are presented. Dr. John Gordon discussed about the interaction of endothelium with granulocytes and mediators produced. Dr. Tim Williams made an experiment about the C5a and vascular permeability. Dr. Williams Buurman made a presentation about the endothelial cells of dogs.

The article provides information on the topics discussed at a meeting organized by the Section of Clinical Immunology & Allergy in Great Britain. The meeting brought together groups who are using molecular biological, immunological and imaging techniques for studying heart diseases. The precision of the methods tackled in the meeting has been of value in studies which examined small differences between patients and control subjects.

This article reports on the case study related to painful bruising syndrome with vasculitis treated by plasmapheresis. The subject was a female, aged 38 years. Since 1964 the subject has had recurrent episodes of tender lumps in the skin, often associated with acute dyspnoea. Less frequently she has had haemoptysis, dysphagia and abdominal pain with melaena. The skin lesions have usually started as tender erythematous oedema, becoming purpuric and sometimes ulcerating. Individual lesions last upwards of several days. They vary in size from 2 to 20 cm across, occurring particularly on the legs, trunk and arms but no part of the skin surface has been spared. Similar lesions have been seen by indirect laryngoscopy in the pharynx and larynx.

The riboflavin analogues, roseoflavin and 8-aminoriboflavin, inhibit malaria parasite proliferation by targeting riboflavin utilization. To determine their mechanism of action, we generated roseoflavin-resistant parasites by in vitro evolution. Relative to wild-type, these parasites were 4-fold resistant to roseoflavin and cross-resistant to 8-aminoriboflavin. Whole genome sequencing of the resistant parasites revealed a missense mutation leading to an amino acid change (L672H) in the gene coding for a putative flavokinase ( Pf FK), the enzyme responsible for converting riboflavin into the cofactor flavin mononucleotide (FMN). To confirm that the L672H mutation is responsible for the phenotype, we generated parasites with the missense mutation incorporated into the Pf FK gene. The IC 50 values for roseoflavin and 8-aminoriboflavin against the roseoflavin-resistant parasites created through in vitro evolution were indistinguishable from those against parasites in which the missense mutation was introduced into the native Pf FK. We also generated two parasite lines episomally expressing GFP-tagged versions of either the wild-type or mutant forms of Pf FK. We found that Pf FK-GFP localizes to the parasite cytosol and that immunopurified Pf FK-GFP phosphorylated riboflavin, roseoflavin, and 8-aminoriboflavin. The L672H mutation increased the K M for roseoflavin, explaining the resistance phenotype. Mutant Pf FK is no longer capable of phosphorylating 8-aminoriboflavin, but its antiplasmodial activity against resistant parasites can still be antagonized by increasing the extracellular concentration of riboflavin, consistent with it also inhibiting parasite growth through competitive inhibition of Pf FK. Our findings, therefore, are consistent with roseoflavin and 8-aminoriboflavin inhibiting parasite proliferation by inhibiting riboflavin phosphorylation and via the generation of toxic flavin cofactor analogues.

Malaria continues to be a significant burden, particularly in Africa, which accounts for 95% of malaria deaths worldwide. Despite advances in malaria treatments, malaria eradication is hampered by insecticide and antimalarial drug resistance. Consequently, the need to discover new antimalarial lead compounds remains urgent. To help address this need, we evaluated the antiplasmodial activity of twenty-two amides and thioamides with pyridine cores and their non-pyridine analogues. Twelve of these compounds showed in vitro anti-proliferative activity against the intraerythrocytic stage of Plasmodium falciparum, the most virulent species of Plasmodium infecting humans. Thiopicolinamide 13i was found to possess submicromolar activity (IC 50  = 142 nM) and was >88-fold less active against a human cell line. The compound was equally effective against chloroquine-sensitive and -resistant parasites and did not inhibit β-hematin formation, pH regulation or PfATP4. Compound 13i may therefore possess a novel mechanism of action., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Same-day mastectomy (SDM) protocols have been shown to be safe, and their use increased up to four-fold compared to pre-pandemic rates. We sought to identify factors that predict overnight patient admission and evaluate the associated cost of care., Study Design: Patients undergoing mastectomy from March 2020 to April 2022 were analyzed. Patients' demographics, tumor characteristics, operative details, perioperative factors, 30-day complications, fixed and variable cost, and contribution margin (CM) were compared between those who underwent SDM vs. those who required overnight admission after mastectomy (OAM)., Results: Of a total of 183 patients with planned SDM, 104 (57%) had SDM and 79 (43%) had OAM. Both groups had similar demographic, tumor, and operative characteristics. OAM patients were more likely to be preoperative opioid users (POU) (p=0.002), have higher American Society of Anesthesiology (ASA) class (p= 0.028), and more likely to have procedure start time (PST) after 12:00 PM (49% vs. 33%, p=0.033). The rates of 30-day unplanned postoperative events were similar between SDM and OAM. POU (OR 3.62 CI 1.56 - 8.40), PACU length of stay greater than one hour (OR 1.17 CI 1.01 - 1.37), and PST after 12:00 PM (OR 2.56 CI 1.19 - 5.51), were independent predictors of OAM on multivariate analysis. Both fixed ($ 5,545 vs $4,909, p=0.03) and variable costs ($6,426 vs $4,909, p=0.03) were higher for OAM compared to SDM. CM, was not significantly different between the two groups (-$431 SDM vs -$734 OAM, p=0.46)., Conclusions: Preoperative opioid use, ASA class, longer PACU length of stay, and PST after noon predict a higher likelihood of admission following planned SDM. OAM translated to higher costs, but not to decreased profit for the hospital., (Copyright © 2024 by the American College of Surgeons. Published by Wolters Kluwer Health, Inc. All rights reserved.)

Toxoplasma gondii is a pervasive apicomplexan parasite that can cause severe disease and death in immunocompromised individuals and the developing foetus. The treatment of toxoplasmosis often leads to serious side effects and novel drugs and drug targets are therefore actively sought. In 2014, Mageed and colleagues suggested that the T. gondii pantothenate synthetase, the enzyme responsible for the synthesis of the vitamin B 5 (pantothenate), the precursor of the important cofactor, coenzyme A, is a good drug target. Their conclusion was based on the ability of potent inhibitors of the M. tuberculosis pantothenate synthetase to inhibit the proliferation of T. gondii tachyzoites. They also reported that the inhibitory effect of the compounds could be antagonised by supplementing the medium with pantothenate, supporting their conclusion that the compounds were acting on the intended target. Contrary to these observations, we find that compound SW314, one of the compounds used in the Mageed et al. study and previously shown to be active against M. tuberculosis pantothenate synthetase in vitro, is inactive against the T. gondii pantothenate synthetase and does not inhibit tachyzoite proliferation, despite gaining access into the parasite in situ. Furthermore, we validate the recent observation that the pantothenate synthetase gene in T. gondii can be disrupted without detrimental effect to the survival of the tachyzoite-stage parasite in the presence or absence of extracellular pantothenate. We conclude that the T. gondii pantothenate synthetase is not essential during the tachyzoite stage of the parasite and it is therefore not a target for drug discovery against T. gondii tachyzoites., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Apicomplexans are widespread parasites of humans and other animals, and include the causative agents of malaria (Plasmodium species) and toxoplasmosis (Toxoplasma gondii). Existing anti-apicomplexan therapies are beset with issues around drug resistance and toxicity, and new treatment options are needed. The mitochondrial electron transport chain (ETC) is one of the few processes that has been validated as a drug target in apicomplexans. To identify new inhibitors of the apicomplexan ETC, we developed a Seahorse XFe96 flux analyzer approach to screen the 400 compounds contained within the Medicines for Malaria Venture 'Pathogen Box' for ETC inhibition. We identified six chemically diverse, on-target inhibitors of the ETC in T. gondii, at least four of which also target the ETC of Plasmodium falciparum. Two of the identified compounds (MMV024937 and MMV688853) represent novel ETC inhibitor chemotypes. MMV688853 belongs to a compound class, the aminopyrazole carboxamides, that were shown previously to target a kinase with a key role in parasite invasion of host cells. Our data therefore reveal that MMV688853 has dual targets in apicomplexans. We further developed our approach to pinpoint the molecular targets of these inhibitors, demonstrating that all target Complex III of the ETC, with MMV688853 targeting the ubiquinone reduction (Qi) site of the complex. Most of the compounds we identified remain effective inhibitors of parasites that are resistant to Complex III inhibitors that are in clinical use or development, indicating that they could be used in treating drug resistant parasites. In sum, we have developed a versatile, scalable approach to screen for compounds that target the ETC in apicomplexan parasites, and used this to identify and characterize novel inhibitors., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Hayward et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)