Postnatal dietary supplementation with either gangliosides or choline: Effects on spatial short-term memory in artificially-reared rats

This study addressed the hypothesis that dietary supplementation with either gangliosides or choline during the brain growth spurt would enhance short-term spatial memory. Male Long-Evans rats were reared artificially from postnatal days (PD) 5–18 and were fed diets containing either (i) choline chloride 1250 mg/l (CHL), (ii) choline chloride 250 mg/l and GD3 24 mg/l (GNG) or (iii) choline chloride 250 mg/l (STD). A fourth group (SCK) was reared normally. Rats were weaned onto AIN 93G diet and on PD 35 were trained on a cued delayed- matching-to-place version of the Morris water maze. All groups learned to swim to the beacon that indicated the platform position on the first trial; similarly, on the second un-cued trial, the distance swam to reach the platform decreased to the same extent in all groups over the five days of training. The groups also responded in the same way to an increase in delay between the first and second trial from 1 min to 1 h, showing an increase in the distance swam, accompanied by a decrease in the number of direct swims to the platform. Thus, all rats were equally proficient at using spatial short-term memory, regardless of the choline or ganglioside content of the preweaning diet.     

Novel actin filaments from Bacillus thuringiensis form nanotubules for plasmid DNA segregation

Here we report the discovery of a bacterial DNA-segregating actin-like protein (BtParM) from Bacillus thuringiensis, which forms novel antiparallel, two-stranded, supercoiled, nonpolar helical filaments, as determined by electron microscopy. The BtParM filament features of supercoiling and forming antiparallel double-strands are unique within the actin fold superfamily, and entirely different to the straight, double-stranded, polar helical filaments of all other known ParMs and of eukaryotic F-actin. The BtParM polymers show dynamic assembly and subsequent disassembly in the presence of ATP. BtParR, the DNA-BtParM linking protein, stimulated ATP hydrolysis/phosphate release by BtParM and paired two supercoiled BtParM filaments to form a cylinder, comprised of four strands with inner and outer diameters of 57 Å and 145 Å, respectively. Thus, in this prokaryote, the actin fold has evolved to produce a filament system with comparable features to the eukaryotic chromosome-segregating microtubule.During bacterial cell division, equal distribution of replicated plasmids to the two daughter cells ensures their stable inheritance. Type II plasmid segregation systems consist of an actin-like protein (ParM) capable of nucleotide-dependent filament formation and a centrosome-like DNA region (parC), which are linked by an adaptor protein ParR. The model ParCMR system is that of the Escherichia coli R1 plasmid (1). ParM-R1 forms actin-like double-helical straight polar filaments (2), which are paired into randomly oriented bundles. The antiparallel pairing of at least two filaments is required to push apart two R1-ParR/parC complexes (3). All other ParMs, which have been experimentally verified to segregate DNA, including AlfA from Bacillus subtilis (4) and ParM-pSK41 from Staphylococcus aureus (5), have also been shown by electron microscopy to form polar, double-stranded straight filaments with diameters between 80 and 90 Å, similar to eukaryotic F-actin (6).Actins and microtubules have gained dedicated functions during evolution that vary between eukaryotes and prokaryotes. During cell division, the contractile ring in prokaryotes depends on the microtubule-like protein FtsZ, whereas this task relies on actin in eukaryotes. In contrast, DNA segregation in eukaryotes is orchestrated by microtubules, whereas in prokaryotes plasmid DNA segregation depends largely on the actin-like proteins ParMs, although Walker-type ATPase ParA (type I) systems (7) and microtubule-like TubZ (type III) systems have also been found (8). Therefore, a long-standing question has been whether a functional equivalent of the microtubule-like DNA segregating architecture, a hollow cylinder, can be found in bacteria.Using X-ray crystallography, electron microscopy and biochemical assays, we have identified and characterized a novel DNA partitioning ParCMR system from Bacillus thuringiensis (Bt) encoded on the plasmid pBMB67 (9). The filament-forming motor protein, BtParM, proved to be entirely different from all previously studied ParMs; in contrast to the ParM-R1 model system, it formed dynamic double-stranded antiparallel supercoiled filaments with an outer diameter of 145 Å in the presence of ATP, which paired into four-stranded nanotubules in the presence of the adaptor protein BtParR or with the BtParR/parC complex. This finding demonstrates that some of the properties of the eukaryotic microtubule system in segregating DNA have also been probed during prokaryote evolution using the actin fold.     

Microvascular abnormalities in sickle cell disease: a computer-assisted intravital microscopy study

The conjunctival microcirculation of 18 homozygous sickle cell disease (SCD) patients during steady-state, painful crisis, and postcrisis conditions was recorded on high-resolution videotapes using intravital microscopy. Selected videotape sequences were subsequently coded, frame-captured, studied, and blindly analyzed using computer-assisted image analysis protocols. At steady-state (baseline), all SCD patients exhibited some of the following morphometric abnormalities: abnormal vessel diameter, comma signs, blood sludging, boxcar blood flow phenomenon, distended vessels, damaged vessels, hemosiderin deposits, vessel tortuosity, and microaneurysms. There was a decrease in vascularity (diminished presence of conjunctival vessels) in SCD patients compared with non-SCD controls, giving the bulbar conjunctiva a "blanched" avascular appearance in most but not all SCD patients during steady-state. Averaged steady-state red cell velocity in SCD patients was slower than in non-SCD controls. During painful crisis, a further decrease in vascularity (caused by flow stoppage in small vessels) and a 36.7% +/- 5.2% decrease in large vessel (mostly venular) diameter resulted. In addition, the conjunctival red cell velocities either slowed significantly (6.6% +/- 13.1%; P <.01) or were reduced to a trickle (unmeasurable) during crisis. The microvascular changes observed during crisis were transient and reverted to steady-state baseline after resolution of crisis. When combined, intravital microscopy and computer-assisted image analysis (computer-assisted intravital microscopy) represent the availability of a noninvasive tool to quantify microvascular abnormalities in vascular diseases, including sickle cell disease. The ability to identify and relocate the same conjunctival vessels for longitudinal studies uniquely underscores the applicability of this quantitative real-time technology.     

Concomitant acute osteomyelitis and squamous cell carcinoma of the foot: a case report

Squamous cell carcinoma of the foot is a common malignant neoplasm with a high potential for metastasis. Squamous cell carcinoma arising in chronic osteomyelitis has been widely reported; however, its presence in combination with acute osteomyelitis of the foot is not well known. This article presents such a case that demonstrates the importance of early recognition with appropriate management for limb salvage and successful oncologic outcome.     

Rapid noninvasive optical imaging of tissue composition in breast tumor margins

Background

In women undergoing breast conserving surgery (BCS), up to 60% can require re-excision. Our objective is to develop an optically based technology which can differentiate benign from malignant breast tissues intraoperatively through differences in tissue composition factors.

Methods

A prospective study of optical imaging of BCS margins is being performed. Optical images are transformed into tissue composition maps with parameters of total hemoglobin concentration, b-carotene concentration and scattering. The predicted outcome is then compared to the margin-level pathology.

Results

Fifty-five margins from 48 patients have undergone assessment. Within 34 specimens with pathologically confirmed positive margins, the ratio map of b-carotene/scattering showed the most significant difference reflecting a decrease in adipose and an increase in cell density within malignant margins (p=.002). These differences were notable in both in-situ and invasive disease.

Conclusions

We present a novel optical spectral imaging device that provides a rapid, non-destructive assay of the tissue composition of breast tumor margins.     

Selective blockade of BAFF for the prevention and treatment of systemic lupus erythematosus nephritis in NZM2410 mice

Objective

To determine whether BAFF or combined BAFF/APRIL blockade is effective in a mouse model of systemic lupus erythematosus (SLE) nephritis characterized by rapidly progressive glomerulosclerosis.

Methods

NZM2410 mice at early and late stages of SLE nephritis were treated with a short course of BAFF‐R‐Ig or TACI‐Ig fusion protein. Proteinuria and serologic profile were evaluated every 2 weeks. Immunohistochemical, flow cytometric, and enzyme‐linked immunospot analyses of the spleen, kidney, and bone marrow were performed after 8 weeks and after 33 weeks.

Results

A short course of selective blockade of BAFF alone was sufficient to prevent and treat SLE nephritis in NZM2410 mice, despite the formation of pathogenic autoantibodies. Decreases in spleen size and B cell depletion persisted for more than 33 weeks after treatment and resulted in secondary decreases in CD4 memory T cell formation and activation of splenic and peripheral monocytes. Immune complex deposition in the kidneys was dissociated from renal damage and from activation of renal endothelial and resident dendritic cells.

Conclusion

Selective blockade of BAFF alone, which resulted in B cell depletion and splenic collapse, was sufficient to prevent and treat the disease in this model of noninflammatory SLE nephritis. This shows that the inflammatory microenvironment may be a determinant of the outcome of B cell modulation strategies.

     

Programmed Death-1: from gene to protein in autoimmune human myasthenia gravis

The key role of an inhibitory receptor, Programmed Death-1, has been evaluated in 273 patients with autoimmune myasthenia gravis. At the genetic level, SNP's genotyping showed no significant association to the disease. Gene expressions in patients were not different from that in controls. Interestingly, at the cell-surface protein level, there were significant elevated levels of PD-1 on T cells and its ligand PD-L1 on monocytes in the patients compared to controls. However, we could not demonstrate any secreted soluble forms of PD-1 among the patients and controls. Thus, our study shows PD-1 might have a natural regulatory property behind MG.     

Polymorphisms in PDCD1 gene are not associated with Wegener’s granulomatosis

Genetic association of programmed cell death-1 (PDCD1) has been implicated in several autoimmune inflammatory disorders. Hence, in this study, our main objective is to evaluate the association of PDCD1 gene to Wegener’s granulomatosis (WG). We, thus, analyzed three single nucleotide polymorphisms (SNPs) in PDCD1 gene among WG patients and controls. Further, we quantified circulating serum levels of soluble (s) PD-1 in patients and controls. The methodologies used were ABI Taqman allelic discrimination and restriction fragment length polymorphism for genotyping and in-house ELISA for quantifying sPD-1. Statistical relevance was analyzed by Fischer’s exact test. As a result, reduced AA homozygote for SNP in intron-1 was observed, among the patients. However, no association was demonstrated after Bonferroni correction. Also, no differences in genotype and allele frequency were elucidated for SNPs in intron-4 and exon-5. Moreover, we could not demonstrate circulating sPD-1. In conclusion, we show no association of selected SNPs in PDCD1 gene with WG.