Reconsidering the relation between serum homocysteine and red blood cell distribution width: a cross-sectional study of a large cohort

Purpose: In a recent small sample study, red blood cell distribution width (RDW) was suggested as a predictor of homocysteine levels. The current study was aimed to reexamine this association in a large scale sample.

Methods: A retrospective cross-sectional study of healthy adults, conducted at Rabin Medical Center, during 2000–2014. Data were retrieved from the medical charts and a logistic regression controlling for interfering factors was carried out. Sensitivity analysis was implemented by exclusion of individuals with anaemia.

Results: Five thousand, five hundred fifty-four healthy individuals were included. Mean serum homocysteine level was 10.10 (SD 2.72) μmol/L. 34.4% of the study population had a homocysteine level higher than the upper limit of normal (10.8?μmol/L). Homocysteine showed no association with RDW (OR 1.00; 95% CI 0.97–1.03), but increased with age (OR 1.05; 95% CI 1.04–1.06) and decreased with a rise in haemoglobin (OR 0.77; 95% CI 0.71–0.83), and in the mean corpuscular volume (OR 0.86; 95% CI 0.85–0.88). Exclusion of individuals with anaemia did not reveal an association between homocysteine and RDW but found a somewhat smaller association between haemoglobin and RDW [OR 0.82; 95% CI 0.73–0.91].

Conclusions: In our large scale sample we did not find an association between RDW and serum homocysteine.     

The Tactile Communication between Cryptocentrus steinitzi (Pisces,Gobiidae) and Alpheus purpurilenticularis (Crustacea,Alpheidae)

The tactile alarm system between the symbiotic goby Cryptocentrus steinitzi and its burrowing shrimp partner Alpheus purpurilenticularis was investigated by underwater observations in the northern Red Sea. Warning signals by the goby which elicit the retreat of the shrimp into its burrow consist mainly of rapid tail flicks transmitted to the shrimp through its long antenna. No warning signals are given without that contact. The daily rhythm of the antennal contacts was described. Warning signals are emitted by the goby in a selective manner only in response to the approach of certain species of fish to the burrow entrance. The response of the shrimp to warning signals was described. The goby-shrimp communication system was used to study predator recognition in a series of controlled experiments. The sequence of the acts of the goby and shrimp was analyzed.     

16S rRNA Phylogeny of Sponge-Associated Cyanobacteria

Phylogenetic analyses of 16S rRNA sequences of sponge-associated cyanobacteria showed them to be polyphyletic, implying that they derived from multiple independent symbiotic events. Most of the symbiont sequences were affiliated to a group of Synechococcus and Prochlorococcus species. However, other symbionts were related to different groups, such as the Oscillatoriales.     

Low and high affinity receptors mediate cellular uptake of heparanase

Heparanase is an endoglycosidase which cleaves heparan sulfate and hence participates in degradation and remodeling of the extracellular matrix. Importantly, heparanase activity correlated with the metastatic potential of tumor-derived cells, attributed to enhanced cell dissemination as a consequence of heparan sulfate cleavage and remodeling of the extracellular matrix barrier. Heparanase has been characterized as a glycoprotein, yet glycan biochemical analysis was not performed to date. Here, we applied the Qproteometrade mark GlycoArray kit to perform glycan analysis of heparanase, and compared the kit results with the more commonly used biochemical analyses. We employed fibroblasts isolated from patients with I-cell disease (mucolipidosis II), fibroblasts deficient of low density lipoprotein receptor-related protein and fibroblasts lacking mannose 6-phosphate receptor, to explore the role of mannose 6-phosphate in heparanase uptake. Iodinated heparanase has been utilized to calculate binding affinity. We provide evidence for hierarchy of binding to cellular receptors as a function of heparanase concentration. We report the existence of a high affinity, low abundant (i.e., low density lipoprotein receptor-related protein, mannose 6-phosphate receptor), as well as a low affinity, high abundant (i.e., heparan sulfate proteoglycan) receptors that mediate heparanase binding, and suggest that these receptors co-operate to establish high affinity binding sites for heparanase, thus maintaining extracellular retention of the enzyme tightly regulated.     

Beta-glycosphingolipids improve glucose intolerance and hepatic steatosis of the Cohen diabetic rat

A link between altered levels of various gangliosides and the development of insulin resistance was described in transgenic mice. Naturally occurring glycosphingolipids were shown to exert immunomodulatory effects in a natural killer T (NKT) cell-dependent manner. This study examined whether glycosphingolipid-induced modulation of the immune system may reduce pancreatic and liver steatosis and stimulate insulin secretion in the Cohen diabetes-sensitive (CDS) rat, a lean model of non-insulin-resistant, nutritionally induced diabetes. Four groups of CDS rats fed a diabetogenic diet were treated with daily intraperitoneal injections of glycosphingolipids beta-glucosylceramide, beta-lactosylceramide, a combination of both (IGL), or vehicle (PBS) for up to 45 days. Immune modulation was assessed by fluorescence-activated cell sorting analysis of intrahepatic and intrasplenic lymphocytes. Steatosis was assessed by MRI imaging and histological examination of liver and pancreas, Blood glucose and plasma insulin concentrations were assessed during an oral glucose tolerance test. Administration of glycosphingolipids, particularly IGL, increased intrahepatic trapping of CD8 T and NKT lymphocytes. Pancreatic and liver histology were markedly improved and steatosis was reduced in all treated groups compared with vehicle-treated rats. Insulin secretion was restored after glycosphingolipid treatment, resulting in improved glucose tolerance. The immunomodulatory effect of beta-glycosphingolipids improved the beta-cell function of the hyperglycemic CDS rat. Thus our results suggest a role for the immune system in the pathogenesis of diabetes in this model.