Toll-like receptor 4 deficiency: Smaller infarcts,but nogain in function

Backgound  

It has been reported that Toll-like receptor 4 (TLR4) deficiency reduces infarct size after myocardial ischemia/reperfusion (MI/R). However, measurement of MI/R injury was limited and did not include cardiac function. In a chronic closed-chest model we assessed whether cardiac function is preserved in TLR4-deficient mice (C3H/HeJ) following MI/R, and whether myocardial and systemic cytokine expression differed compared to wild type (WT).     

Defective,deleted or converted CYP21B gene and negative association with a rare restriction fragment length polymorphism allele of the factor B gene in congenital adrenal hyperplasia

Summary Defects in the enzyme, steroid 21-hydroxylase, result in congenital adrenal hyperplasia (CAH), a common autosomal recessive disorder of cortisol biosynthesis. The gene encoding this protein (CYP21B) and a closely linked pseudogene (CYP21A) have been mapped in the HLA complex on chromosome 6p, adjacent to the complement genes C4B and C4A, about 80 kb from the factor B gene. Molecular analyses of patients with CAH have shown that the cause of the defect may be either a deletion, a point mutation or a conversion of the active gene. Linkage of the disease to HLA has previously been studied by several groups. We have analyzed DNAs from patients with classical and non-classical CAH and from their family members, by probing with CYP21, C4 and BF cDNAs. In 70% of the CAH haplotypes studied, the defective CYP21B gene was indistinguishable from its structurally intact corresponding gene in Southern blot analysis, and presumably bore point mutations. In the remaining chromosomes, evidence for gene conversions, deletions and various deleterious mutations of the CYP21B gene is given. Moreover, our linkage studies show that a polymorphic TaqI cleavage site in the factor B gene, recently described by us, may be a new and useful genetic marker, because we found this TaqI restriction site only in unaffected haplotypes carrying functional CYP21B genes and, therefore, in negative association with the defective CYP21B gene.     

Alpha-melanocyte-stimulating hormone immunoreactivity in human melanoma metastases extracts

Seven human melanoma metastases were extracted in order to check the possible presence of any alpha-melanocyte stimulating hormone (MSH) immunoreactivity. The aim of that study was to provide some explanation for, mainly, two observations that we have already made and reported: 1) increased plasma alpha-MSH levels in melanoma of tumour-bearing patients as compared with tumour-free patients; 2) the presence of specific alpha-MSH receptors on human melanoma cells in culture. We could measure large amounts of immunoreactive alpha-MSH in all tumours ranging from 0.31 to 4.27 pmoles per g of wet tissue. Further identification of the extracted material by high-performance liquid chromatography revealed compounds of higher molecular weight and more hydrophobic than synthetic alpha-MSH. In addition, purified extracts could also displace 125I-labelled alpha-MSH from its cellular binding sites in an alpha-MSH specific radio-receptor binding assay. Our findings would suggest a possible presence of some hormone precursor(s) inside the melanoma tumours.     

Comparative effects of trichothecene mycotoxins on bovine platelet function: Acetyl T-2 toxin,a more potent inhibitor than T-2 toxin

The effects of the trichothecene mycotoxins (acetyl T-2 toxin, T-2 toxin, HT-2 toxin, palmityl T-2 toxin, diacetoxyscirpenol (DAS), deoxynivalenol (DON), and T-2 tetraol) on bovine platelet function were examined in homologous plasma stimulated with platelet activating factor (PAF). The mycotoxins inhibited platelet function with the following order of potency: acetyl T-2 toxin > palmityl T-2 toxin = DAS > HT-2 toxin = T-2 toxin. While T-2 tetraol was completely ineffective as an inhibitor, DON exhibited minimal inhibitory activity at concentrations above 10×10^?4M. The stability of the platelet aggregates formed was significantly reduced in all mycotoxin treated platelets compared to that of the untreated PAF controls. It is suggested that the increased sensitivity of PAF stimulated bovine platelets to the more lipophilic mycotoxins may be related to their more efficient partitioning into the platelet membrane compared to the more hydrophilic compounds.     

An extensive review on antifungal approaches in the treatment of mucormycosis

During the period of COVID-19, the occurrences of mucormycosis in immunocompromised patients have increased significantly. Mucormycosis (black fungus) is a rare and rapidly progressing fungal infection associated with high mortality and morbidity in India as well as globally. The causative agents for this infection are collectively called mucoromycetes which are the members of the order Mucorales. The diagnosis of the infection needs to be performed as soon as the occurrence of clinical symptoms which differs with types of Mucorales infection. Imaging techniques magnetic resonance imaging or computed tomography scan, culture testing, and microscopy are the approaches for the diagnosis. After the diagnosis of the infection is confirmed, rapid action is needed for the treatment in the form of antifungal therapy or surgery depending upon the severity of the infection. Delaying in treatment declines the chances of survival. In antifungal therapy, there are two approaches first-line therapy (monotherapy) and combination therapy. Amphotericin B ( 1 ) and isavuconazole ( 2 ) are the drugs of choice for first-line therapy in the treatment of mucormycosis. Salvage therapy with posaconazole ( 3 ) and deferasirox ( 4 ) is another approach for patients who are not responsible for any other therapy. Adjunctive therapy is also used in the treatment of mucormycosis along with first-line therapy, which involves hyperbaric oxygen and cytokine therapy. There are some drugs like VT-1161 ( 5 ) and APX001A ( 6 ), Colistin, SCH 42427, and PC1244 that are under clinical trials. Despite all these approaches, none can be 100% successful in giving results. Therefore, new medications with favorable or little side effects are required for the treatment of mucormycosis.     

Bacterial pollution of seawater: comparison of technics of sampling and analysis

From sampling in three areas neighbouring Tunis, the first polluted, the second contaminated and the third clean, the authors point out that the technic of multiple samples using the "Lactose Broth" is the most sensible to faecal pollution.     

Monoclonal antibodies to rabbit liver cytochrome P-448

Cytochrome P-448 (mol wt 55,000 Daltons) from rabbit liver was purified to a specific content of 16.6 nmol/mg. Mice were immunised with this preparation, their spleens removed and dissociated lymphocytes hybridised with myeloma cells. Four monoclonal antibodies against cytochrome P-448 were raised and partially characterised. All four antibodies interacted with cytochrome P-448 in intact microsomal fractions and selectively immunoadsorbed cytochrome P-448 from solubilised microsomal preparations. One of the antibodies inhibited benzo[a] pyrene hydroxylase activity in a reconstituted system, one had no effect on activity and two increased activity. The possible applications of such antibodies are discussed.     

Saikosaponin-d,a novel SERCA inhibitor,induces autophagic cell death in apoptosis-defective cells

Autophagy is an important cellular process that controls cells in a normal homeostatic state by recycling nutrients to maintain cellular energy levels for cell survival via the turnover of proteins and damaged organelles. However, persistent activation of autophagy can lead to excessive depletion of cellular organelles and essential proteins, leading to caspase-independent autophagic cell death. As such, inducing cell death through this autophagic mechanism could be an alternative approach to the treatment of cancers. Recently, we have identified a novel autophagic inducer, saikosaponin-d (Ssd), from a medicinal plant that induces autophagy in various types of cancer cells through the formation of autophagosomes as measured by GFP-LC3 puncta formation. By computational virtual docking analysis, biochemical assays and advanced live-cell imaging techniques, Ssd was shown to increase cytosolic calcium level via direct inhibition of sarcoplasmic/endoplasmic reticulum Ca²⁺ ATPase pump, leading to autophagy induction through the activation of the Ca²⁺/calmodulin-dependent kinase kinase–AMP-activated protein kinase–mammalian target of rapamycin pathway. In addition, Ssd treatment causes the disruption of calcium homeostasis, which induces endoplasmic reticulum stress as well as the unfolded protein responses pathway. Ssd also proved to be a potent cytotoxic agent in apoptosis-defective or apoptosis-resistant mouse embryonic fibroblast cells, which either lack caspases 3, 7 or 8 or had the Bax-Bak double knockout. These results provide a detailed understanding of the mechanism of action of Ssd, as a novel autophagic inducer, which has the potential of being developed into an anti-cancer agent for targeting apoptosis-resistant cancer cells.     

Embryonic Cardiomyocyte,but Not Autologous Stem Cell Transplantation,Restricts Infarct Expansion,Enhances Ventricular Function,and Improves Long-Term Survival

Aims

Controversy exists in regard to the beneficial effects of transplanting cardiac or somatic progenitor cells upon myocardial injury. We have therefore investigated the functional short- and long-term consequences after intramyocardial transplantation of these cell types in a murine lesion model.

Methods and Results

Myocardial infarction (MI) was induced in mice (n = 75), followed by the intramyocardial injection of 1−2×10⁵ luciferase- and GFP-expressing embryonic cardiomyocytes (eCMs), skeletal myoblasts (SMs), mesenchymal stem cells (MSCs) or medium into the infarct. Non-treated healthy mice (n = 6) served as controls. Bioluminescence and fluorescence imaging confirmed the engraftment and survival of the cells up to seven weeks postoperatively. After two weeks MRI was performed, which showed that infarct volume was significantly decreased by eCMs only (14.8±2.2% MI+eCM vs. 26.7±1.6% MI). Left ventricular dilation was significantly decreased by transplantation of any cell type, but most efficiently by eCMs. Moreover, eCM treatment increased the ejection fraction and cardiac output significantly to 33.4±2.2% and 22.3±1.2 ml/min. In addition, this cell type exclusively and significantly increased the end-systolic wall thickness in the infarct center and borders and raised the wall thickening in the infarct borders. Repetitive echocardiography examinations at later time points confirmed that these beneficial effects were accompanied by better survival rates.

Conclusion

Cellular cardiomyoplasty employing contractile and electrically coupling embryonic cardiomyocytes (eCMs) into ischemic myocardium provoked significantly smaller infarcts with less adverse remodeling and improved cardiac function and long-term survival compared to transplantation of somatic cells (SMs and MSCs), thereby proving that a cardiomyocyte phenotype is important to restore myocardial function.