Investigating cellular and molecular mechanisms of neurogenesis in Capitella teleta sheds light on the ancestor of Annelida.

BACKGROUND: Diverse architectures of nervous systems (NSs) such as a plexus in cnidarians or a more centralized nervous system (CNS) in insects and vertebrates are present across Metazoa, but it is unclear what selection pressures drove evolution and diversification of NSs. One underlying aspect of this diversity lies in the cellular and molecular mechanisms driving neurogenesis, i.e. generation of neurons from neural precursor cells (NPCs). In cnidarians, vertebrates, and arthropods, homologs of SoxB and bHLH proneural genes control different steps of neurogenesis, suggesting that some neurogenic mechanisms may be conserved. However, data are lacking for spiralian taxa. RESULTS: To that end, we characterized NPCs and their daughters at different stages of neurogenesis in the spiralian annelid Capitella teleta. We assessed cellular division patterns in the neuroectoderm using static and pulse-chase labeling with thymidine analogs (EdU and BrdU), which enabled identification of NPCs that underwent multiple rounds of division. Actively-dividing brain NPCs were found to be apically-localized, whereas actively-dividing NPCs for the ventral nerve cord (VNC) were found apically, basally, and closer to the ventral midline. We used lineage tracing to characterize the changing boundary of the trunk neuroectoderm. Finally, to start to generate a genetic hierarchy, we performed double-fluorescent in-situ hybridization (FISH) and single-FISH plus EdU labeling for neurogenic gene homologs. In the brain and VNC, Ct-soxB1 and Ct-neurogenin were expressed in a large proportion of apically-localized, EdU+ NPCs. In contrast, Ct-ash1 was expressed in a small subset of apically-localized, EdU+ NPCs and subsurface, EdU- cells, but not in Ct-neuroD+ or Ct-elav1+ cells, which also were subsurface. CONCLUSIONS: Our data suggest a putative genetic hierarchy with Ct-soxB1 and Ct-neurogenin at the top, followed by Ct-ash1, then Ct-neuroD, and finally Ct-elav1. Comparison of our data with that from Platynereis dumerilii revealed expression of neurogenin homologs in proliferating NPCs in annelids, which appears different than the expression of vertebrate neurogenin homologs in cells that are exiting the cell cycle. Furthermore, differences between neurogenesis in the head versus trunk of C. teleta suggest that these two tissues may be independent developmental modules, possibly with differing evolutionary trajectories.

Management of adult spontaneous spondylodiscitis and its rising incidence.

INTRODUCTION: Spondylodiscitis refers to the infection of the intervertebral disc and osteomyelitis of the adjacent endplates, and it is uncommon in the developed world. Broad consensus indicates its incidence is on the rise. METHODS: The aim of this retrospective study was twofold. First, we sought to give an up-to-date incidence estimate by comparing case presentation over two time periods (1995-1999 and 2008-2011). Data from the England and Wales census in 2001 and 2011 were used for incidence estimation. The second part of this study aimed to generate management guidance from data from medical and radiographic records of the 2008-2011 patient cohort. RESULTS: The incidence of adult spontaneous spondylodiscitis in the local region between 2008 and 2011 was 3.67/100,000 per year, representing a 150% increase from the incidence in 1995-1999. Our data demonstrate that methicillin sensitive Staphylococcus aureus remains the most common offending pathogen of spontaneous spondylodiscitis. The mean C-reactive protein (CRP) level remained at >30mg/l after a month of starting antibiotic treatment in both medically and surgically managed groups. CONCLUSIONS: Evidence suggests that the incidence of spondylodiscitis is on the rise. A review of our case series has demonstrated the effectiveness of intravenous antibiotic therapy. While no official guidance exists for when to switch from intravenous to oral antibiotics, our study shows that CRP at 1 month is >30mg/l and we recommend 6 weeks of intravenous therapy, followed by 6 further weeks of oral therapy.

Ascorbate induced cross-linking of oxyhemoglobin subunits.

Ascorbic acid during oxidation in vitro can generate H2O2 which induces non-disulphide covalent cross-linking of coincubated oxyhemoglobin. The cross-linking phenomenon mediated by H2O2 takes place possibly without the involvement of hydroxyl radicals as evident from the failure of radical scavengers like mannitol and dimethyl sulphoxide as well as metal-chelator, to inhibit the process. This pro-oxidant effect of ascorbic acid may have physiological significance in red blood cells in vivo.

Hepatoprotective effect of Swertia chirata on rat.

Present work was undertaken to ascertain the hepatoprotective effect of Swertia chirata in albino rats. Intraperitoneal injection of CCl4 (1 ml/kg body wt on every 72 hr. for 16 days) significantly increased serum aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), and alkaline phosphatase (ALP) activities and bilirubin level in rat, but liver glycogen and serum cholesterol levels were decreased. Histologically it produced hepatocytic necrosis especially in the centrilobular region. Simultaneous treatments with S. Chirata (in different doses, viz, 20, 50 and 100 mg/kg body wt daily) and CCl4 (similar dose to that mentioned earlier) caused improvement at both biochemical and histopathological parameters compared to that of CCl4 treatment alone but it was most effective when S. chirata was administered in a moderate dose (50 mg/kg body wt).

Comparative evaluation of two maternal weight-height indices during pregnancy.

Three hundred forty one primiparous women and their offsprings were the subjects of the study. Mothers were subjected to weight and height measurement as well as hemoglobin estimation. The weight for height ratio index (WHRI) and weight-height product index (WHPI) were calculated. Both WHRI and WHPI were studied in relation to birth weight (BW). WHPI was found to be superior over WHRI as it explained greater per cent variation in birth weight. The means for BW increased and incidence of low birth weight babies decreased significantly with increase of WHPI in each WHRI group.

Iron deficiency in sicle cell disease.

Iron studies were performed on 25 children with homozygous sickle cell disease. The majority (80%) of patients had never been transfused. Surprisingly, the results showed that all had low serum iron and low transferrin saturation. Three children had no marrow iron stores while the rest had diminished amounts of iron. This may be an important finding in view of recent efforts at fortifying common salt with iron. The exact effects of iron deficiency on sickle cell disease are not known and a controlled trial is called for.

The tesla discharge as a spectroscopic source for the study of excimer laser transitions.

A method for studying the pressure and temperature dependence of rare gas halide and halogen emissions is described. The tesla discharge utilized in this method is characterized in detail with respect to its temporal behavior and its radiant output. The light is found to be produced in moderately intense pulses as short as 0.5 micros in duration. Average dc radiant powers for strong emitters can exceed 5 mW. The method appears suitable for the study of most emitters that can be produced by electron beam excitation.

Indian childhood cirrhosis: an inherited disorder of tryptophan metabolism?

Urine samples from members of 29 families of patients with Indian childhood cirrhosis (ICC) and nine families with related disorders gave positive reactions when tested with ferric chloride. Column chromatography showed that this was due to the presence of abnormally large amounts of tryptophan metabolites, notably 3-hydroxyanthranilic acid. Affected pedigrees had a significantly greater prevalence of peptic ulcer, adult cirrhosis, diabetes mellitus, migraine, and Parkinsonism than a control population. ICC may result from an inborn error of tryptophan metabolism in susceptible ethnic groups.