Taxonomy and systematics of the genus Pinus based on morphological, biogeographical and biochemical characters

For a long time, systematists have subdivided the genus Pinus into Diploxylon and Haploxylon according to morpho-anatomy and the number of needles. Nevertheless, divergent views remain regarding the structure of these two subgenera, mainly at the section and subsection levels. We propose to clarify some of these uncertainties by studying 45 Pinus taxa of different origins. Our results, based on morphometric and biochemical (flavonoids) parameters, complement those obtained from classical anatomical and morphological studies, and also modern macro-molecular markers (proteins, DNA). We confirm the subdivision of the genus into Pinus = Diploxylon versus Strobus = Haploxylon and the further sectioning of the first subgenus into sections Pinus and Trifoliae. Moreover, we specify the different subsections, whereby the contents of the methylated flavonol isorhamnetin coupled with needle morphometry play a significant role (subsections Pinus vs. Pinaster in section Pinus, Australes + Ponderosae vs. Contortae in section Trifoliae). Given that isorhamnetin proceeds from quercetin by the irreversible action of an O-methyl-transferase, this methylated flavonol becomes a dynamic marker in such way that the taxa rich in isorhamnetin can be considered as more “derived = evolved”. In addition, there exists a highly significant negative correlation between methylation index and number of needles. Consequently, the pines from the Holarctic Strobus group (with five needles and low isorhamnetin contents) can be considered as “ancestral”, in reference to a Laurasian origin of the genus. In the subgenus Pinus, the Nearctic group (=section Trifoliae) remains near the ancestral base. On the other hand, the Holarctic subset “densiflorae” is connected to the other members (mainly European) of the polyphyletic subsection Pinus, in particular with series “sylvestres”. Because of their very high contents of isorhamnetin, the Mediterranean pines result from an accentuation of this evolutionary trend (=subsection Pinaster). In fact, the pines growing under hot and dry climates (Mediterranean region) are highly evolved compared to those from cold and/or wet regions (Eurasia and North America but also, to a lesser extent, the south-eastern USA and East Asia). Our dynamic propositions based on plant phenolics data complete those from more modern macromolecular (DNA, proteins) studies.     

Bioconjugates of curcumin display improved protection against glutathione depletion mediated oxidative stress in a dopaminergic neuronal cell line: Implications for Parkinson’s disease

Oxidative stress is implicated in mitochondrial dysfunction associated with neurodegeneration in Parkinson’s disease (PD). Depletion of the cellular antioxidant glutathione (GSH) resulting in oxidative stress is considered as an early event in neurodegeneration. We previously showed that curcumin, a dietary polyphenol from turmeric induced GSH synthesis in experimental models and protected against oxidative stress. Here we tested the effect of three bioconjugates of curcumin (involving diesters of demethylenated piperic acid, valine and glutamic acid) against GSH depletion mediated oxidative stress in dopaminergic neuronal cells and found that the glutamic acid derivative displayed improved neuroprotection compared to curcumin.     

Spectrum of peripheral neuropathies associated with surgical interventions; A neurophysiological assessment

Background

We hypothesized that a wide range of surgical procedures may be complicated by neuropathies, not just in close proximity but also remote from procedural sites. The aim of this study was to classify post-operative neuropathies and the procedures associated with them.

Methods

We retrospectively identified 66 patients diagnosed with post-procedure neuropathies between January 2005 and June 2008. We reviewed their referral cards and medical records for patient demographics, information on procedures, symptoms, as well as clinical and neurophysiological findings.

Results

Thirty patients (45.4%) had neuropathies remote from procedural sites and 36 patients (54.5%) had neuropathies in close proximity to procedural sites. Half of the remote neuropathies (15/30) developed following relatively short procedures. In 27% of cases (8/30) remote neuropathies were bilateral. Seven patients developed neuropathies remote from operative sites following hip arthroplasties (7/30: 23.3%), making hip arthroplasty the most common procedure associated with remote neuropathies. Sciatic neuropathies due to hip arthroplasty (12/36, 33.3%) accounted for the majority of neuropathies occurring in close proximity to operative sites. Five medial cutaneous nerve of forearm neuropathies occurred following arterio-venous fistula (AVF) formation.

Conclusions

An array of surgical procedures may be complicated by neuropathy. Almost half of post-procedure neuropathies occur remote from the site of procedure, emphasizing the need to try to prevent not just local, but also remote neuropathies. Mechanical factors and patient positioning should be considered in the prevention of post-operative neuropathies. There is a possible association between AVF formation and medial cutaneous nerve of forearm neuropathy, which requires further study for validation.     

Twin fetus in fetu in a child: a case report and review of the literature

Introduction

Necrotizing fasciitis is a rare condition with a mortality rate of around 34%. It can be mono- or polymicrobial in origin. Monomicrobial infections are usually due to group A streptococcus and their incidence is on the rise. They normally occur in healthy individuals with a history of trauma, surgery or intravenous drug use. Post-operative necrotizing fasciitis is rare but accounts for 9 to 28% of all necrotizing fasciitis. The incidence of wound infection following saphenofemoral junction ligation and vein stripping is said to be less than 3%, although this complication is probably under-reported. We describe a case of group A streptococcus necrotizing fasciitis following saphenofemoral junction ligation and vein stripping.

Case Presentation

A 39-year-old woman presented three days following a left sided saphenofemoral junction ligation with long saphenous vein stripping at another institution. She had a three day history of fever, rigors and swelling of the left leg. She was pyrexial and shocked. She had a very tender, swollen left groin and thigh, with a small blister anteriorly and was in acute renal failure. She was prescribed intravenous penicillin and diagnosed with necrotizing fasciitis. She underwent extensive debridement of her left thigh and was commenced on clindamycin and imipenem. Post-operatively, she required ventilatory and inotropic support with continuous veno-venous haemofiltration. An examination 12 hours after surgery showed no requirement for further debridement. A group A streptococcus, sensitive to penicillin, was isolated from the debrided tissue. A vacuum assisted closure device was fitted to the clean thigh wound on day four and split-skin-grafting was performed on day eight. On day 13, a wound inspection revealed that more than 90% of the graft had taken. Antibiotics were stopped on day 20 and she was discharged on day 22.

Conclusion

Necrotizing fasciitis is a very serious complication for a relatively minor, elective procedure. To the best of our knowledge, this is the first report in the English-language literature of this complication arising from a standard saphenofemoral junction ligation and vein stripping. It highlights the need to be circumspect when offering patients surgery for non-life-threatening conditions.     

Infiltration by CD4+ and CD8+ lymphocytes in bursa of chickens infected with Infectious Bursal Disease Virus (IBDV): strain-specific differences

In order to investigate if there is any definite correlation between the degree of T-cell response in the bursa of Fabricius (BF) and the virulence of Infectious Bursal Disease (IBD) virus strains, chickens were infected with strains of different virulence i.e. mild (Lukert strain), intermediate (Georgia strain) or invasive intermediate (IV-95 strain). At various times post-inoculation, bursal samples were collected to study virus specific histopathological lesions, the distribution of viral antigen and the extent of T-cell infiltration in the bursa. Most severe bursal lesions were induced by IV-95 strain (the invasive intermediate strain), whereas Lukert, the mild strain caused the least severe lesions. The number of virus positive cells in the bursa was highest in chickens infected with IV-95 strain. Substantial infiltration of CD4+ and CD8+ T-cells in the bursal follicles of virus-infected groups was observed from 4 d.p.i. onwards. The magnitude of T-cell response was more in the birds infected with intermediate (Georgia) or invasive intermediate strains of virus than chickens inoculated with mild (Lukert) strain, even when 10-fold higher doses of the inoculums were used. PHA responses to peripheral lymphocytes were found suppressed in all the groups of chickens only transiently. The results indicate that the magnitude of T-cell responses in BF during IBDV infection is influenced more by the virulence of virus strain rather than the quantum of viral load in BF. Over all these studies may have implications in understanding the role of T-cells in pathogenesis and immunity in IBD.     

Efficient incorporation of positively charged 2', 3'-dideoxynucleoside-5'-triphosphates by DNA polymerases and their application in 'direct-load' DNA sequencing

A series of charge-modified, dye-labeled 2′, 3′-dideoxynucleoside-5′-triphosphates have been synthesized and evaluated as reagents for dye-terminator DNA sequencing. Unlike the commonly used dye-labeled terminators, these terminators possess a net positive charge and migrate in the opposite direction to dye-labeled Sanger fragments during electrophoresis. Post-sequencing reaction purification is not required to remove unreacted nucleotide or associated breakdown products prior to electrophoresis. Thus, DNA sequencing reaction mixtures can be loaded directly onto a separating medium such as a sequencing gel. The charge-modified nucleotides have also been shown to be more efficiently incorporated by a number of DNA polymerases than regular dye-labeled dideoxynucleotide terminators or indeed normal dideoxynucleoside-5′-triphosphates.     

Protein kinase C-associated kinase can activate NFkappaB in both a kinase-dependent and a kinase-independent manner

Protein kinase C-associated kinase (PKK, also known as RIP4/DIK) activates NFkappaB when overexpressed in cell lines and is required for keratinocyte differentiation in vivo. However, very little is understood about the factors upstream of PKK or how PKK activates NFkappaB. Here we show that certain catalytically inactive mutants of PKK can activate NFkappaB, although to a lesser degree than wild type PKK. The deletion of specific domains of wild type PKK diminishes the ability of this enzyme to activate NFkappaB; the same deletions made on a catalytically inactive PKK background completely ablate NFkappaB activation. PKK may be phosphorylated by two specific mitogen-activated protein kinase kinase kinases, MEKK2 and MEKK3, and this interaction may in part be mediated through a critical activation loop residue, Thr184. Catalytically inactive PKK mutants that block phorbol ester-induced NFkappaB activation do not interfere with, but unexpectedly enhance, the activation of NFkappaB by these two mitogen-activated protein kinase kinase kinases. Taken together, these data indicate that PKK may function in both a kinase-dependent as well as a kinase-independent manner to activate NFkappaB.     

The minimal structural domains required for neural cell adhesion molecule polysialylation by PST/ST8Sia IV and STX/ST8Sia II

A limited number of mammalian proteins are modified by polysialic acid, with the neural cell adhesion molecule (NCAM) being the most abundant of these. We hypothesize that polysialylation is a protein-specific glycosylation event and that an initial protein-protein interaction between polysialyltransferases and glycoprotein substrates mediates this specificity. To evaluate the regions of NCAM required for recognition and polysialylation by PST/ST8Sia IV and STX/ST8Sia II, a series of domain deletion proteins were generated, co-expressed with each enzyme, and their polysialylation analyzed. A protein consisting of the fifth immunoglobulin-like domain (Ig5), which contains the reported sites of polysialylation, and the first fibronectin type III repeat (FN1) was polysialylated by both enzymes, whereas a protein consisting of Ig5 alone was not polysialylated by either enzyme. This demonstrates that the Ig5 domain of NCAM and FN1 are sufficient for polysialylation, and suggests that the FN1 may constitute an enzyme recognition and docking site. Two other NCAM mutants, NCAM-6 (Ig1-5) and NCAM-7 (FN1-FN2), were weakly polysialylated by PST/ST8Sia IV, suggesting that a weaker enzyme recognition site may exist within the Ig domains, and that glycans in the FN region are polysialylated. Further analysis indicated that O-linked oligosaccharides in NCAM-7, and O-linked and N-linked glycans in full-length NCAM, are polysialylated when these proteins are co-expressed with the polysialyltransferases in COS-1 cells. Our data support a model in which the polysialyltransferases bind to the FN1 of NCAM to polymerize polysialic acid chains on appropriately presented glycans in adjacent regions.