Decreased brain venous vasculature visibility on susceptibility-weighted imaging venography in patients with multiple sclerosis is related to chronic cerebrospinal venous insufficiency

Background

The potential pathogenesis between the presence and severity of chronic cerebrospinal venous insufficiency (CCSVI) and its relation to clinical and imaging outcomes in brain parenchyma of multiple sclerosis (MS) patients has not yet been elucidated. The aim of the study was to investigate the relationship between CCSVI, and altered brain parenchyma venous vasculature visibility (VVV) on susceptibility-weighted imaging (SWI) in patients with MS and in sex- and age-matched healthy controls (HC).

Methods

59 MS patients, 41 relapsing-remitting and 18 secondary-progressive, and 33 HC were imaged on a 3T GE scanner using pre- and post-contrast SWI venography. The presence and severity of CCSVI was determined using extra-cranial and trans-cranial Doppler criteria. Apparent total venous volume (ATVV), venous intracranial fraction (VIF) and average distance-from-vein (DFV) were calculated for various vein mean diameter categories: < .3 mm, .3-.6 mm, .6-.9 mm and > .9 mm.

Results

CCSVI criteria were fulfilled in 79.7% of MS patients and 18.2% of HC (p < .0001). Patients with MS showed decreased overall ATVV, ATVV of veins with a diameter < .3 mm, and increased DFV compared to HC (all p < .0001). Subjects diagnosed with CCSVI had significantly increased DFV (p < .0001), decreased overall ATVV and ATVV of veins with a diameter < .3 mm (p < .003) compared to subjects without CCSVI. The severity of CCSVI was significantly related to decreased VVV in MS (p < .0001) on pre- and post-contrast SWI, but not in HC.

Conclusions

MS patients with higher number of venous stenoses, indicative of CCSVI severity, showed significantly decreased venous vasculature in the brain parenchyma. The pathogenesis of these findings has to be further investigated, but they suggest that reduced metabolism and morphological changes of venous vasculature may be taking place in patients with MS.

     

A chemical-genetic screen reveals a mechanism of resistance to PI3K inhibitors in cancer

Linking the molecular aberrations of cancer to drug responses could guide treatment choice and identify new therapeutic applications. However, there has been no systematic approach for analyzing gene-drug interactions in human cells. Here we establish a multiplexed assay to study the cellular fitness of a panel of engineered isogenic cancer cells in response to a collection of drugs, enabling the systematic analysis of thousands of gene-drug interactions. Applying this approach to breast cancer revealed various synthetic-lethal interactions and drug-resistance mechanisms, some of which were known, thereby validating the method. NOTCH pathway activation, which occurs frequently in breast cancer, unexpectedly conferred resistance to phosphoinositide 3-kinase (PI3K) inhibitors, which are currently undergoing clinical trials in breast cancer patients. NOTCH1 and downstream induction of c-MYC over-rode the dependency of cells on the PI3K-mTOR pathway for proliferation. These data reveal a new mechanism of resistance to PI3K inhibitors with direct clinical implications.     

Loss-of-function mutations in PTPN11 cause metachondromatosis, but not Ollier disease or Maffucci syndrome

Metachondromatosis (MC) is a rare, autosomal dominant, incompletely penetrant combined exostosis and enchondromatosis tumor syndrome. MC is clinically distinct from other multiple exostosis or multiple enchondromatosis syndromes and is unlinked to EXT1 and EXT2, the genes responsible for autosomal dominant multiple osteochondromas (MO). To identify a gene for MC, we performed linkage analysis with high-density SNP arrays in a single family, used a targeted array to capture exons and promoter sequences from the linked interval in 16 participants from 11 MC families, and sequenced the captured DNA using high-throughput parallel sequencing technologies. DNA capture and parallel sequencing identified heterozygous putative loss-of-function mutations in PTPN11 in 4 of the 11 families. Sanger sequence analysis of PTPN11 coding regions in a total of 17 MC families identified mutations in 10 of them (5 frameshift, 2 nonsense, and 3 splice-site mutations). Copy number analysis of sequencing reads from a second targeted capture that included the entire PTPN11 gene identified an additional family with a 15 kb deletion spanning exon 7 of PTPN11. Microdissected MC lesions from two patients with PTPN11 mutations demonstrated loss-of-heterozygosity for the wild-type allele. We next sequenced PTPN11 in DNA samples from 54 patients with the multiple enchondromatosis disorders Ollier disease or Maffucci syndrome, but found no coding sequence PTPN11 mutations. We conclude that heterozygous loss-of-function mutations in PTPN11 are a frequent cause of MC, that lesions in patients with MC appear to arise following a "second hit," that MC may be locus heterogeneous since 1 familial and 5 sporadically occurring cases lacked obvious disease-causing PTPN11 mutations, and that PTPN11 mutations are not a common cause of Ollier disease or Maffucci syndrome.     

The effect of season on oocyte quality and developmental competence in Italian Mediterranean buffaloes (Bubalus bubalis)

At Italian latitudes, buffalo (Bubalus bubalis) is a seasonally polyestrous species, showing an improved reproductive efficiency when daylight decreases (autumn). The aim of the present study was to evaluate the influence of the season on buffalo oocyte recovery rate, on oocyte quality, assessed on morphological basis, and developmental competence after in vitro fertilization. For this purpose, buffalo ovaries were collected from a local abattoir and the oocytes obtained by aspirating the follicles were evaluated, classified and, if considered of good quality, devolved to the different procedures of IVEP. In general, no differences were found in terms of oocyte recovery per ovary among seasons, but interestingly, the percentage of small oocytes was higher (P<0.05) during spring and summer (0.9±0.1 and 0.9±0.2) compared to autumn and winter (0.3±0.1 and 0.2±0.1). Both cleavage and embryo rate increased during the period from October to December (71.7±3.1 and 26.5±2.1, respectively) compared to the period from April to June (58.0±2.4 and 18.8±1.6, respectively), thus reflecting the in vivo reproductive behavior. Nevertheless, it is worth emphasizing that transferrable embryos were produced in vitro, even during the unfavorable season, but with decreased efficiency. In conclusion, these results suggest to avoid the oocyte collection during spring when planning OPU trials in order to save resources and improve the benefits/costs ratio.     

Long term effect of Ovum Pick-up in buffalo species

The aim of this study was to evaluate the effect of an Ovum Pick-up (OPU) treatment carried out for 9 months in buffalo (Bubalus bubalis) species. Eight pluriparous non-lactating buffalo cows underwent OPU for 9 months. Recovered cumulus enclosed oocytes (COCs) were classified and COCs suitable for in vitro embryo production (IVEP) were in vitro matured (IVM), fertilized (IVF) and cultured (IVC) to the blastocyst (Bl) stage. Animals were monitored for a total period of 270 days, but at the summer solstice, follicular turnover decreased and at the 68-day of the trial, we decided to increase the OPU sampling interval from 3-4 to 7 days. It was therefore possible to distinguish two phases: a first phase (18 sessions), during which OPU was carried out twice weekly and a second phase (16 sessions) during which OPU sessions were performed weekly. This reduction did not modify the percentage of good quality COCs, while the incidence of grade D COCs decreased (P<0.01). Furthermore, embryo production was higher in the second phase, either if embryos were calculated on the total recovered COCs (8.3% vs. 21.4%; P<0.01) and on grade A+B COCs (13.0% vs. 32.1%; P<0.01), that supposedly should have given similar blastocyst yield. During the total period of the trial it was possible to distinguish a first period of 6 months (34 sessions) characterized by blastocyst production (0.36 blastocyst/buffalo/session), followed by an unproductive period of 3 months (12 sessions), during which embryos were not produced. During the first 6 months a higher (P<0.01) number of follicles (5.06 vs. 3.71), small follicles (3.38 vs. 2.07), total COCs (2.58 vs. 1.56) and good quality (A+B) COCs (1.51 vs. 0.94) per subject/session were recorded compared to the last 3 months. No Blastocyst were produced during the second period, even if the percentage of grade A+B COCs was similar to that recorded during the first period. In conclusion, buffalo cows submitted to repeated OPU sampling for a 9-month period, showed a decline of follicle recruitment and oocyte collection after the first two months of samplings. After 6-month of samplings, in spite of the quality grade of the collected oocytes, we found a drop in their developmental competence.     

Structural characterization and epitope mapping of the glutamic acid/alanine-rich protein from Trypanosoma congolense: defining assembly on the parasite cell surface

Trypanosoma congolense is an African trypanosome that causes serious disease in cattle in Sub-Saharan Africa. The four major life cycle stages of T. congolense can be grown in vitro, which has led to the identification of several cell-surface molecules expressed on the parasite during its transit through the tsetse vector. One of these, glutamic acid/alanine-rich protein (GARP), is the first expressed on procyclic forms in the tsetse midgut and is of particular interest because it replaces the major surface coat molecule of bloodstream forms, the variant surface glycoprotein (VSG) that protects the parasite membrane, and is involved in antigenic variation. Unlike VSG, however, the function of GARP is not known, which necessarily limits our understanding of parasite survival in the tsetse. Toward establishing the function of GARP, we report its three-dimensional structure solved by iodide phasing to a resolution of 1.65 Å. An extended helical bundle structure displays an unexpected and significant degree of homology to the core structure of VSG, the only other major surface molecule of trypanosomes to be structurally characterized. Immunofluorescence microscopy and immunoaffinity-tandem mass spectrometry were used in conjunction with monoclonal antibodies to map both non-surface-disposed and surface epitopes. Collectively, these studies enabled us to derive a model describing the orientation and assembly of GARP on the surface of trypanosomes. The data presented here suggest the possible structure-function relationships involved in replacement of the bloodstream form VSG by GARP as trypanosomes differentiate in the tsetse vector after a blood meal.     

Derivatization of haemoglobin with periodate-generated reticulation agents: evaluation of oxidative reactivity for potential blood substitutes

Periodate modification of the sugar moiety in sugars, including adenosine triphosphate (ATP), has previously been employed in order to prepare dialdehyde-type reagents, which were then utilized in crosslinking reactions on haemoglobin, yielding polymerized material with useful dioxygen-binding properties and hence proposed as possible artificial oxygen carriers ('blood substitutes'). Here, the periodate protocol is shown to be applicable to a wider range of oxygen-containing compounds, illustrated by starch and polyethylene glycol. Derivatization protocols are described for haemoglobin with such periodate-treated crosslinking agents, and the dioxygen-binding properties and redox reactivities are investigated for the derivatized haemoglobins, with emphasis on pro-oxidative properties. There is a general tendency of the derivatization to result in higher autooxidation rates. The peroxide reactivity of the met (ferric) form is also affected by derivatization, as witnessed, among others, by varying yields of ferryl [Fe (IV)-oxo] and free radical generated. In cell, culture tests (human umbilical vein epithelial cells, HUVEC), the derivatization protocols show no toxic effect.     

Segregation analysis of overweight body condition in an experimental cat population

The goal of this study was to analyze the mode of inheritance of an overweight body condition in an experimental cat population. The cat population consisted of 95 cats of which 81 cats could be clearly classified into lean or overweight using the body condition scoring system according to Laflamme. The lean or overweight classification was then used for segregation analyses. Complex segregation analyses were employed to test for the significance of one environmental and 4 genetic models (general, mixed inheritance, major gene, and polygene). The general genetic model fit the data significantly better than the environmental model (P ≤ 0.0013). Among all other models employed, the major gene model explained the segregation of the overweight phenotype best. This is the first study in which a genetic component could be shown to be responsible for the development of overweight in cats.     

Chemoresistance of Plasmodium falciparum and Plasmodium vivax parasites in Brazil: consequences on disease morbidity and control

In Brazil, malaria still remains a clinically important febrile syndrome for local populations and travelers, occurring mostly in the Amazon Basin. This review aims to report the main efforts employed to control this disease since the 1940s and the emergence of Plasmodium falciparum and Plasmodium vivax chemoresistance to chloroquine and sulphadoxine-pyrimethamine among other drugs. Additionally, in vivo, in vitro and molecular studies as well as malaria chemoresistance consequences on disease morbidity and policy treatment guidelines were commented.