Anatomic study of the vasculature of the submental artery flap

The submental artery island flap is a versatile option in head and neck reconstruction. This flap may be used for the coverage of perioral, intraoral, and other facial defects, leaving a relatively acceptable donor-site scar. In this study, the submental region of 13 formalin-fixed cadavers was dissected bilaterally. Comprehensive anatomical information regarding the pedicle of the flap and its relationship with the important adjacent structures is provided. The mean values of the measurements of the facial and submental arteries were as follows: the facial artery was 2.7 mm in diameter at the origin, and it crossed the mandibular border 26.6 mm from the mandibular angle. The origin of the submental artery was 27.5 mm from the origin of the facial artery, 5.0 mm from the mandibular border, and 23.8 mm from the mandibular angle. The diameter of the submental artery was 1.7 mm at the origin. The artery was found mostly to course superficial to the submandibular gland. In one case, the artery passed through the gland. The total length of the submental artery was 58.9 mm. The artery anastomosed with the contralateral artery in 92 percent of the cadavers. The submental artery was deep to the anterior belly of the digastric muscle in 81 percent of the cases. This study presents detailed anatomical data about the location, dimension, and relationship of the facial artery, the submental artery, and the submental vein that may be useful during dissection of the submental artery island flap.     

Erythrocyte antioxidant defense response against cigarette smoking in humans--the glutathione S-transferase vulnerability

Cigarette smoking leads to uptake of a multitude of reactive chemicals including many electrophiles and may also give rise to oxidative stress. Human red blood cells are important targets for electrophilic and oxidant foreign compounds. We investigated the oxidative stress in erythrocytes upon cigarette smoking, and the response of antioxidant defense system against it. With this aim, simultaneous determination of erythrocyte superoxide dismutase (SOD), selenium dependent glutathione peroxidase (Se-GPx), catalase (CAT), glutathione S-transferase (GST) activities and plasma levels of thiobarbituric acid reactive substances (TBARS), and the degree of erythrocyte membrane lipid peroxidation (EMLP) were carried out in blood samples of smokers and their controls. Plasma TBARS levels and EMLP in smokers were significantly higher than the control levels (p < 0.01 and p < 0.005, respectively). SOD activity was diminished in smokers compared to nonsmoker controls (p < 0.005). Erythrocyte Se-GPx activity was also found significantly diminished in smokers (p < 0.005), while plasma Se-GPx activity was not changed. We observed that erythrocyte CAT activity was not different in smokers compared to nonsmoker controls. We found that the erythrocyte GST activity is significantly lower in young adult smokers (3.03 +/- 0.18 U/mg protein; mean +/- SEM; n = 46) than in nonsmoking contemporaries (3.98 +/- 0.26 U/mg protein; mean +/- SEM; n = 41). Together with previously reported data, it can be concluded that the decrease in GST activity leads to extra GST synthesis during erythrocyte proliferation. The same data were also analyzed for the sex differences. The statistically significant differences remained the same between nonsmoker and smoker females. Only EMLP degree and SOD activity were significantly different between nonsmoker and smoker males; however, when compared the parameters between male and female nonsmokers, GST activity was found to be significantly higher in females than that of males.     

Neuronal damage in autoimmune neuroinflammation mediated by the death ligand TRAIL

Here, we provide evidence for a detrimental role of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in neural death in T cell-induced experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Clinical severity and neuronal apoptosis in brainstem motor areas were substantially reduced upon brain-specific blockade of TRAIL after induction of EAE through adoptive transfer of encephalitogenic T cells. Furthermore, TRAIL-deficient myelin-specific lymphocytes showed reduced encephalitogenicity when transferred to wild-type mice. Conversely, intracerebral delivery of TRAIL to animals with EAE increased clinical deficits, while naive mice were not susceptible to TRAIL. Using organotypic slice cultures as a model for living brain tissue, we found that neurons were susceptible to TRAIL-mediated injury induced by encephalitogenic T cells. Thus, in addition to its known immunoregulatory effects, the death ligand TRAIL contributes to neural damage in the inflamed brain.     

Relaxant effects of pravastatin, atorvastatin and cerivastatin on isolated rat aortic rings

Increasing evidence suggests that statins may have pleiotropic effects on vascular wall independent of their cholesterol lowering properties. In the present study, we investigated the acute vascular effects of pravastatin, atorvastatin and cerivastatin on rat isolated aortic rings. Statins effectively and comparably relaxed the aortic rings precontracted submaximally with noradrenaline, in a concentration-dependent manner, in which a high potency was observed with cerivastatin. Endothelium removal or incubation of the aortic rings with nitric oxide synthase inhibitor L-NOARG (10(-4) M) and/or cyclooxygenase inhibitor indomethacin (10(-5) M) significantly attenuated the acute vasorelaxation induced by either of statin. Additionally, different from the other two statins, a significant reduction was observed in response to cerivastatin in the presence of KATP channel inhibitor, glibenclamide (10(-5) M) and Na+- K+ ATPase inhibitor, ouabain (10(-4) M). Furthermore, pretreatment of the rings with the cholesterol precursor mevalonate (10(-3) M) significantly inhibited the endothelium-mediated relaxant effects of the statins. Our findings suggest that statins could acutely modulate vascular tone importantly by endothelium-dependent and mevalonate-related pathways.     

The phylogenetic origin of oskar coincided with the origin of maternally provisioned germ plasm and pole cells at the base of the Holometabola

The establishment of the germline is a critical, yet surprisingly evolutionarily labile, event in the development of sexually reproducing animals. In the fly Drosophila, germ cells acquire their fate early during development through the inheritance of the germ plasm, a specialized maternal cytoplasm localized at the posterior pole of the oocyte. The gene oskar (osk) is both necessary and sufficient for assembling this substance. Both maternal germ plasm and oskar are evolutionary novelties within the insects, as the germline is specified by zygotic induction in basally branching insects, and osk has until now only been detected in dipterans. In order to understand the origin of these evolutionary novelties, we used comparative genomics, parental RNAi, and gene expression analyses in multiple insect species. We have found that the origin of osk and its role in specifying the germline coincided with the innovation of maternal germ plasm and pole cells at the base of the holometabolous insects and that losses of osk are correlated with changes in germline determination strategies within the Holometabola. Our results indicate that the invention of the novel gene osk was a key innovation that allowed the transition from the ancestral late zygotic mode of germline induction to a maternally controlled establishment of the germline found in many holometabolous insect species. We propose that the ancestral role of osk was to connect an upstream network ancestrally involved in mRNA localization and translational control to a downstream regulatory network ancestrally involved in executing the germ cell program.     

Effect of nitrogen limitation on enrichment of activated sludge for PHA production

Polyhydroxyalkanoates (PHA) are good candidates to plastics because of their material properties similar to conventional plastics and complete biodegradability. The use of activated sludge can be a cheaper alternative to pure cultures for PHA production. In this study, effect of nitrogen limitation during acclimatization period of biomass on production of polyhydroxyalkanoate was investigated. Activated sludge was selected in two sequencing batch reactors operated with and without nitrogen limitation. Batch tests were performed to examine polymer productions of activated sludges acclimatized to different nitrogen regimes. Responses of biomass to different organic loading rates, organic acids, and carbon to nitrogen (C/N) ratios were studied by determining specific polymer storage rate, polymer storage yield, and sludge polymer content of biomasses. Results obtained from batch experiments showed that concentrations of polymer accumulated by two different sludges increased directly with initial substrate concentration. Observed highest polymer yields for the biomasses enriched with and without nitrogen deficiency were 0.69 g COD PHA g(-1) COD S and 0.51 g COD PHA g(-1) COD S, and corresponding polymer contents of biomasses were 43.3% (g COD PHA g(-1) COD X) and 38.3% (g COD PHA g(-1) COD X), respectively. Polymer yields for both biomasses decreased with substrate shift however, biomass enriched with nitrogen deficiency adapted well to acetate-propionate mixture. The results presented in this study showed that polymer storage ability of biomass was improved more under dynamic conditions with nitrogen deficiency when compared to that without nitrogen deficiency. Limiting ammonia availability during batch experiments also caused higher polymer production by suppressing growth, as well as during enrichment of biomass.     

Protein-Protein Interaction Domains of Bacillus subtilis DivIVA

DivIVA proteins are curvature-sensitive membrane binding proteins that recruit other proteins to the poles and the division septum. They consist of a conserved N-terminal lipid binding domain fused to a less conserved C-terminal domain. DivIVA homologues interact with different proteins involved in cell division, chromosome segregation, genetic competence, or cell wall synthesis. It is unknown how DivIVA interacts with these proteins, and we used the interaction of Bacillus subtilis DivIVA with MinJ and RacA to investigate this. MinJ is a transmembrane protein controlling division site selection, and the DNA-binding protein RacA is crucial for chromosome segregation during sporulation. Initial bacterial two-hybrid experiments revealed that the C terminus of DivIVA appears to be important for recruiting both proteins. However, the interpretation of these results is limited since it appeared that C-terminal truncations also interfere with DivIVA oligomerization. Therefore, a chimera approach was followed, making use of the fact that Listeria monocytogenes DivIVA shows normal polar localization but is not biologically active when expressed in B. subtilis. Complementation experiments with different chimeras of B. subtilis and L. monocytogenes DivIVA suggest that MinJ and RacA bind to separate DivIVA domains. Fluorescence microscopy of green fluorescent protein-tagged RacA and MinJ corroborated this conclusion and suggests that MinJ recruitment operates via the N-terminal lipid binding domain, whereas RacA interacts with the C-terminal domain. We speculate that this difference is related to the cellular compartments in which MinJ and RacA are active: the cell membrane and the cytoplasm, respectively.     

Macrocytic Anemia and Mitochondriopathy Resulting from a Defect in Sideroflexin 4

We used exome sequencing to identify mutations in sideroflexin 4 (SFXN4) in two children with mitochondrial disease (the more severe case also presented with macrocytic anemia). SFXN4 is an uncharacterized mitochondrial protein that localizes to the mitochondrial inner membrane. sfxn4 knockdown in zebrafish recapitulated the mitochondrial respiratory defect observed in both individuals and the macrocytic anemia with megaloblastic features of the more severe case. In vitro and in vivo complementation studies with fibroblasts from the affected individuals and zebrafish demonstrated the requirement of SFXN4 for mitochondrial respiratory homeostasis and erythropoiesis. Our findings establish mutations in SFXN4 as a cause of mitochondriopathy and macrocytic anemia.     

Vagus nerve stimulation inhibits seizure activity and protects blood–brain barrier integrity in kindled rats with cortical dysplasia

AimsThis study investigates the effects of vagus nerve stimulation (VNS) on seizure severity and blood–brain barrier (BBB) integrity in kindled rats with cortical dysplasia (CD).Main methodsPregnant rats were exposed to 145 cGy of gamma-irradiation on day 17 of pregnancy. In offsprings, kindling was induced by giving subconvulsive doses of pentylenetetrazole. Left VNS was performed for 48 h at output currents of 0.5 or 1 mA. Horseradish peroxidase (HRP) was used to study the BBB permeability. Immunohistochemistry for occludin and P-glycoprotein (P-gp) was also performed.Key findingsKindled rats with CD exhibited seizures with mean Racine's scores of 3.57 ± 1.2 during video EEG recording. Kindled animals with CD receiving VNS at 0.5 and 1.0 mA did not exhibit either clinical or electrophysiological signs of seizure. Immunostaining for occludin, a tight junction protein, in hippocampus remained relatively intact in all groups. VNS-treated and -untreated kindled animals with CD revealed intense immunostaining for P-gp in hippocampal formation (P < 0.01). Electron microscopic observations revealed frequent transport vesicles containing electron-dense HRP reaction products in the cytoplasm of brain capillary endothelial cells in both cerebral cortex and hippocampus of kindled animals with CD. Those which were exposed to 1 mA VNS were observed to have brain capillary endothelial cells largely devoid of HRP reaction products in both cerebral cortex and hippocampus.SignificanceThe results of this study suggest that VNS therapy at 1 mA inhibits seizure activity and protects BBB integrity by limiting the enhancement of transcellular pathway in kindled animals with CD.