Genome-wide study of DNA methylation shows alterations in metabolic, inflammatory, and cholesterol pathways in ALS

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with an estimated heritability between 40 and 50%. DNA methylation patterns can serve as proxies of (past) exposures and disease progression, as well as providing a potential mechanism that mediates genetic or environmental risk. Here, we present a blood-based epigenome-wide association study meta-analysis in 9706 samples passing stringent quality control (6763 patients, 2943 controls). We identified a total of 45 differentially methylated positions (DMPs) annotated to 42 genes, which are enriched for pathways and traits related to metabolism, cholesterol biosynthesis, and immunity. We then tested 39 DNA methylation-based proxies of putative ALS risk factors and found that high-density lipoprotein cholesterol, body mass index, white blood cell proportions, and alcohol intake were independently associated with ALS. Integration of these results with our latest genome-wide association study showed that cholesterol biosynthesis was potentially causally related to ALS. Last, DNA methylation at several DMPs and blood cell proportion estimates derived from DNA methylation data were associated with survival rate in patients, suggesting that they might represent indicators of underlying disease processes potentially amenable to therapeutic interventions.

Common and rare variant association analyses in amyotrophic lateral sclerosis identify 15 risk loci with distinct genetic architectures and neuron-specific biology

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a lifetime risk of one in 350 people and an unmet need for disease-modifying therapies. We conducted a cross-ancestry genome-wide association study (GWAS) including 29,612 patients with ALS and 122,656 controls, which identified 15 risk loci. When combined with 8,953 individuals with whole-genome sequencing (6,538 patients, 2,415 controls) and a large cortex-derived expression quantitative trait locus (eQTL) dataset (MetaBrain), analyses revealed locus-specific genetic architectures in which we prioritized genes either through rare variants, short tandem repeats or regulatory effects. ALS-associated risk loci were shared with multiple traits within the neurodegenerative spectrum but with distinct enrichment patterns across brain regions and cell types. Of the environmental and lifestyle risk factors obtained from the literature, Mendelian randomization analyses indicated a causal role for high cholesterol levels. The combination of all ALS-associated signals reveals a role for perturbations in vesicle-mediated transport and autophagy and provides evidence for cell-autonomous disease initiation in glutamatergic neurons.

Troubles sexuels chez 78 hémodialysés chroniques marocains de sexe masculin : étude clinique et endocrinienne

PURPOSE

To investigate the correlation between biochemical and endocrine variables with sexual disorders in 78 male patients on chronic hemodialysis at the Ibn Rochd University Hospital (Casablanca-Morocco).

METHODS

Seventy-eight male hemodialysis patients with chronic renal failure were evaluated with regard to their sexual function. All patients answered a personal questionnaire on their sexual activity. Hormone (FSH, LH, prolactin, testosterone, and parathyroid hormone) and zinc and ferritin assays were also performed.

RESULTS

The men reported erection (44.9%), libido (44.9%), ejaculation (26.8%), and orgasm (21.8%) disorders. Gynecomastia was observed in 17.9% of the patients. There was no correlation with weight nor the nature of the causal nephropathy nor with duration of dialysis. Levels of gonadotropins (FSH, LH), prolactin, and parathyroid hormone were elevated. Testosterone levels were low. Ferritinemia was elevated but there was no significant variation in zincemia. There was a negative curvilinear relationship between serum testosterone and sexual disorders, and between gynecomastia and ferritinemia. LH and prolactin levels were positively correlated with gynecomastia.

CONCLUSION

Abnormal hormonal and iron overload could be important factors involved in the complex pathogenesis of sexual dysfunction in chronic renal failure patients undergoning hemodialysis.

Purification and characterization of a new potential in vivo inhibitor of cathepsin L from bovine skeletal muscle

Four papain-inhibiting peaks, labeled F-I, F-II, F-III, and F-IV, were fractionated from a crude bovine muscle extract by gel filtration chromatography on Sephadex G100, and the F-III fraction was analyzed. From F-III, a cysteine proteinase inhibitor was purified by two successive anionic exchange chromatography steps on Q-Sepharose and Mono-Q columns. This inhibitor has a molecular weight of about 30 kDa. Regarding its specificity toward different proteinases, the purified 30 kDa inhibitor was inactive against serine (trypsin and chymotrypsin) and aspartyl (pepsin) families. In contrast, cathepsin L, H, B, and papain, four enzymes of the cysteine class were strongly inhibited suggesting that this inhibitor was specific to the cysteine proteinase group. However, no inhibitory activity was shown against calpains. Kinetic parameters, including inhibition constants (Ki), rate constant for association (kass) and time required for almost complete inhibition of proteinase in vivo were determined. The values are consistent with a possible physiological function for this inhibitor protein in controlling in vivo cathepsin L activity.

The use of iridium-191m for pulmonary blood flow imaging

A preliminary evaluation of the potential utilization of osmium-191/iridium-191m for pulmonary blood flow imaging was performed. This evaluation was part of a more general study concerning the use of 191mIr for first-pass radionuclide angiocardiography (FPRNA). In eight selected patients with suspected pulmonary disease, we generated, from the data collected during FPRNA, an image representing blood flow distribution to the lungs. A software program was developed in order to differentiate the lungs from the heart, to define the wash-in lung phase and finally to construct an image representing pulmonary blood flow distribution. We compared that image with a standard lung perfusion image using technetium-99m macroaggregated albumin (MAA) and plain chest X-ray and computerized tomography (CT). The obtained 191mIr perfusion images showed a spatial activity distribution similar to that seen on 99mTc-MAA lung perfusion scans, and in most cases the same perfusion defects. Disease revealed by plain chest X-ray and CT was nicely correlated with perfusion defects seen on the 191mIr images. The combined information of lung perfusion and dynamic cardiac parameters obtained by FPRNA (right and left ventricular ejection fractions) added another relevant dimension to the clinical picture of patients with pulmonary embolism, chronic obstructive lung disease, lung tumour or suspected congestive heart failure. We conclude that 191mIr may become a practical tool for achieving the conceptually promising approach of combined lung-heart real-time imaging.

Purification and characterisation of a polymorphic low M(r) bovine muscle cysteine proteinase inhibitor: structural identity with fatty-acid-binding proteins

Three low molecular mass cysteine proteinase inhibitors were purified from a bovine skeletal muscle crude extract using a three-step procedure. The crude extract was first subjected to gel filtration on a Sephadex G100 column which separated five active fractions (F-I to F-V). Three papain inhibitors, P1, P2 and P3, were fractionated from the F-V fraction by chromatofocalisation on a poly buffer exchanger column. Purification was completed by chromatography on a Mono Q column. After SDS-PAGE, the three inhibitors showed only one band with an M(r) of 14,300. P1, P2 and P3 appeared to be highly resistant to temperature (40-90 degrees C), pH (3-10), reducing agents (5-50 mM) and to be specific for cysteine proteinases since no activity was detected against either serine or aspartyl proteinases. Although to a varying extent, P1, P2 and P3 inhibited papain, cathepsin B and cathepsin L. Analysis of the peptide mixtures of these inhibitors by RP-HPLC after hydrolysis with CNBr or aspartly endoproteinase N together with their amino acid composition revealed that P1, P2 and P3 cysteine proteinase inhibitors are isoforms of the same protein. As their N-terminal ends were blocked, partial sequence of some of these peptides was determined. Computer search in protein identification resources did not reveal any homology of these sequences with proteinase inhibitors of known primary structure. In contrast, they matched well with different parts of the total sequence of a fatty acid binding protein isolated from bovine heart. This homology was supported by the ability of these inhibitors to bind long chain fatty acids.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of pH adjustment agents on the biologic behavior of osmium-191 impurity in iridium-191m generator eluates

The influence of four pH adjustment agents on the biologic behavior of osmium-191 (191Os) impurity in 191Os/191mIr generator eluates was studied. Extended body clearance and biodistribution studies were performed in mice. The solutions to be injected were obtained by eluting generators with a 0.9% NaCl solution at pH 1. The pH of these eluates was adjusted to 5-9 with succinate, phosphate, lysine or NaOH solution. Our results demonstrate that the biologic behavior of these generator eluates is significantly dependent on the agent used for pH adjustment. Buffering with lysine leads to the best results: (a) the mice show no adverse reaction after injection of 150 human doses and the body clearance is very rapid and (b) more than 75% I.D. at 24 hr postinjection. Preliminary calculations based on these results suggest a significant decrease in the estimated patient radiation dose when lysine buffered 191Os/191mIr generator eluates are used for radionuclide angiography.