A short synthesis of D-glycero-D-manno-heptose 7-phosphate

D-glycero-D-manno-Heptopyranose 7-phosphate-an intermediate in the biosynthesis of nucleotide-activated heptoses-has been prepared in good overall yield from benzyl 5,6-dideoxy-2,3-O-isopropylidene-alpha-D-lyxo-(Z)-hept-5-enofuranoside by a short-step synthesis. Phosphitylation using the phosphoramidite procedure followed by in situ oxidation afforded the corresponding 7-O-phosphotriester derivative in high yield. Subsequent osmylation proceeded in good diastereoselectivity (4:1) to furnish the D-glycero-D-manno-configured derivative, which was separated from the L-glycero-L-gulo-isomer by chromatography. Hydrogenolysis led to simultaneous removal of the benzyl and isopropylidene groups and afforded the target compound in high yield, which serves as a substrate of bacterial heptose 7-phosphate kinases.     

S. aureus-dependent microglial activation is selectively attenuated by the cyclopentenone prostaglandin 15-deoxy-Delta12,14- prostaglandin J2 (15d-PGJ2)

Microglial activation is a hallmark of brain abscess. The continual release of proinflammatory mediators by microglia following bacterial challenge may contribute, in part, to the destruction of surrounding normal tissue characteristic of brain abscess. Therefore, attenuating chronic microglial activation during the course of CNS bacterial infections may have therapeutic benefits. The purpose of this study was to evaluate the ability of the natural peroxisome proliferator-activated receptor (PPAR)-gamma agonist 15-deoxy-Delta12,14- prostaglandin J2 (15d-PGJ2) to modulate microglial activation in response to Staphylococcus aureus, one of the main etiologic agents of brain abscess in humans. 15d-PGJ2 was a potent inhibitor of proinflammatory cytokine (IL-1beta, TNF-alpha, IL-12 p40) and CC chemokine (MIP-1beta, MCP-1) production in primary microglia, but had no effect upon the expression of select CXC chemokines (MIP-2, KC). 15d-PGJ2 also selectively inhibited the S. aureus-dependent increase in microglial TLR2, CD14, MHC class II, and CD40 expression, whereas it had no effect on the co-stimulatory molecules CD80 and CD86. Microarray analysis revealed additional inflammatory mediators modulated by 15d-PGJ2 in primary microglia following S. aureus exposure, the majority of which were chemokines. These results suggest that suppressing microglial activation through the use of 15d-PGJ2 may lead to the sparing of damage to normal brain parenchyma that often results from brain abscess.     

Exogenous zinc improves blood fluidity but has no effect on the mechanisms of vascular response to acetylcholine iontophoresis in humans

Recent findings in cellular signaling function of zinc through the mobilization intracellular calcium or by inducing ATP release suggest that extracellular zinc plays an important role in many physiological functions. However, such an extracellular signaling action of zinc for most cells is not known. Therefore, we investigated whether zinc plays any role in endothe-lium-dependent acetylcholine (ACh)-induced vasodilatation in microvascular beds. Transdermal iontophoresis was used to transport ACh through the forearm skin and cutaneous perfusion was measured using a laser Doppler flowmeter (LDF). Experiments were repeated using (1) zinc instead of ACh to test the effect of zinc ions alone and (2) concomitant iontophoresis of ACh and zinc to explore the effect of zinc on ACh-induced vasodilatation. Although zinc augments blood flow, curve-fitting to LDF signals indicate that zinc has no effect on the neural and endothelial component of ACh-induced vasodilatation. Additionally, no effect of Zn²⁺ on blood flow was found during its iontophoresis alone. Therefore, it is suggested from the Fourier analysis of LDF signals that the Zn⁺ might influence blood fluidity by its action on red blood cells deformability/aggregability during a high-blood-flow condition, which might, in turn, decrease blood viscosity and improve blood flow in vivo.     

A novel membrane-dependent on/off switch mechanism of talin FERM domain at sites of cell adhesion

The activation of heterodimeric (α/β) integrin transmembrane receptors by cytosolic protein talin is crucial for regulating diverse cell-adhesion-dependent processes, including blood coagulation, tissue remodeling, and cancer metastasis. This process is triggered by the coincident binding of N-terminal FERM (four-point-one-protein/ezrin/radixin/moesin) domain of talin (talin-FERM) to the inner membrane surface and integrin β cytoplasmic tail, but how these binding events are spatiotemporally regulated remains obscure. Here we report the crystal structure of a dormant talin, revealing how a C-terminal talin rod segment (talin-RS) self-masks a key integrin-binding site on talin-FERM via a large interface. Unexpectedly, the structure also reveals a distinct negatively charged surface on talin-RS that electrostatically hinders the talin-FERM binding to the membrane. Such a dual inhibitory topology for talin is consistent with the biochemical and functional data, but differs significantly from a previous model. We show that upon enrichment with phosphotidylinositol-4,5-bisphosphate (PIP2) – a known talin activator, membrane strongly attracts a positively charged surface on talin-FERM and simultaneously repels the negatively charged surface on talin-RS. Such an electrostatic “pull-push” process promotes the relief of the dual inhibition of talin-FERM, which differs from the classic “steric clash” model for conventional PIP2-induced FERM domain activation. These data therefore unravel a new type of membrane-dependent FERM domain regulation and illustrate how it mediates the talin on/off switches to regulate integrin transmembrane signaling and cell adhesion.     

The value of CDX2 and cytokeratins 7 and 20 expression in differentiating colorectal adenocarcinomas from extraintestinal gastrointestinal adenocarcinomas: cytokeratin 7-/20+ phenotype is more specific than CDX2 antibody

Background

Breast carcinomas can be classified into five subtypes based on gene expression profiling or immunohistochemical characteristics. Among these subtypes, basal-like breast carcinomas (BLBCs) are one of the most studied group, due to their poor prognosis. The aim of this study was to investigate the prevalance, morphological and immunohistochemical features of BLBCs, in Turkish population.

Methods

Five hundred invasive breast carcinomas were reviewed for several morphological features and immunostained for oestrogen and progesterone receptors, c-ERB-B2, cytokeratin5/6, cytokeratin14, vimentin and epidermal growth factor receptor (EGFR). Basal-like breast carcinoma was defined as a triple negative tumor with cytokeratin5/6 and/or EGFR positive.

Results

The prevalance of BLBC was 9.6%. All medullary carcinomas and 55.6% of metaplastic carcinomas showed basal-like immunophenotype. Patients with BLBC were younger (p=0.04) and had higher-grade tumors (p<0.0001). Morphologic features associated with BLBC included increased mitosis, nuclear pleomorphism, presence of geographic and/or central necrosis, pushing margin of invasion and stromal lymphocytic response (p<0.0001). Presence of prominent nucleoli and vesicular nuclear chromatin were the cytological features correlated with basal-like phenotype (p<0.0001). On multivariate analyses, BLBCs were associated with high mitotic number (p<0.0001), the presence of vesicular chromatin (p=0.004), high tubular grade (p=0.011), lymphocytic response (p=0.031) and the absence of carcinoma insitu (p=0.039). Vimentin was positive in 53.2% of BLBCs, while cytokeratin14 was less frequently expressed (27.7%).

Conclusions

BLBCs have some distinctive, but not pathognomonical, morphological features. Paying attention to these features and adding cytokeratin14 and vimentin to the immunohistochemical panel can help the definitive diagnosis of BLBCs.

Virtual slide

http://www.diagnosticpathology.diagnomx.eu/vs/5962175467857400     

Reproductive biology of Raja clavata (Elasmobranchii: Rajidae) from Southern Black Sea coast around Turkey

Specimens of Raja clavata were monthly collected at the coast of Havaalan? (Trabzon/Turkey) from January 2009 to December 2009 at depths between 20 and 40?m. A total of 230 individuals of thornback ray (131 females and 99 males) were collected by bottom trawls during research cruises. Using logistic regression, it was determined that TL at 50% maturity of males was 718?mm TL and of females 746?mm TL. The ovarian fecundity ranged from 27 to 60 yellow follicles in both ovaries. Females carrying egg cases were found in July and October. Variations in the gonadosomatic and hepatosomatic indices indicated a continuous reproductive cycle during the year.     

Analysis of functional brain connections for positive–negative emotions using phase locking value

In this study, we investigate the brain networks during positive and negative emotions for different types of stimulus (audio only, video only and audio + video) in \(\alpha , \beta\), and \(\gamma\) bands in terms of phase locking value, a nonlinear method to study functional connectivity. Results show notable hemispheric lateralization as phase synchronization values between channels are significant and high in right hemisphere for all emotions. Left frontal electrodes are also found to have control over emotion in terms of functional connectivity. Besides significant inter-hemisphere phase locking values are observed between left and right frontal regions, specifically between left anterior frontal and right mid-frontal, inferior-frontal and anterior frontal regions; and also between left and right mid frontal regions. ANOVA analysis for stimulus types show that stimulus types are not separable for emotions having high valence. PLV values are significantly different only for negative emotions or neutral emotions between audio only/video only and audio only/audio + video stimuli. Finding no significant difference between video only and audio + video stimuli is interesting and might be interpreted as that video content is the most effective part of a stimulus.     

A short synthesis of d-glycero-d-manno-heptose 7-phosphate

d-glycero-d-manno-Heptopyranose 7-phosphate—an intermediate in the biosynthesis of nucleotide-activated heptoses—has been prepared in good overall yield from benzyl 5,6-dideoxy-2,3-O-isopropylidene-α-d-lyxo-(Z)-hept-5-enofuranoside by a short-step synthesis. Phosphitylation using the phosphoramidite procedure followed by in situ oxidation afforded the corresponding 7-O-phosphotriester derivative in high yield. Subsequent osmylation proceeded in good diastereoselectivity (4:1) to furnish the d-glycero-d-manno-configured derivative, which was separated from the l-glycero-l-gulo-isomer by chromatography. Hydrogenolysis led to simultaneous removal of the benzyl and isopropylidene groups and afforded the target compound in high yield, which serves as a substrate of bacterial heptose 7-phosphate kinases.     

Dissolution of cellulose with NMMO by microwave heating

Environmentally friendly microwave heating process was applied to the dissolution of cellulose in N-methylmorpholine-N-oxide (NMMO) with 105–490 W and 2450 MHz microwave energy until the dissolution completed. Microwave heating caused the decrease in the dissolution time and energy consumption. Cellulose/NMMO/water solutions with different cellulose concentrations were converted to the membrane to measure the crystallinity and degree of polymerization. It was shown that microwave heating with the power of 210 W is an alternative heating system for dissolution of cellulose in NMMO. The membranes obtained with two different heating methods showed the same crystallinity and degree of polymerization. As a result, microwave heating has an advantage in shortening reaction times, compared to conventional heating.