Case control polysomnographic studies of sleep disorders in Parkinson's disease

Background

The relationship between a number of primary sleep disorders and Parkinson''s disease (PD) is still debated. There are limited case control polysomnographic studies in PD and most of these study sample sizes are small.

Methodology/Findings

We conducted one of the largest case-control studies involving overnight polysomnographic evaluation, with prospective recruitment of unselected Parkinson''s disease patients and healthy controls from an Asian population. The cases were recruited from the specialized movement disorder outpatient clinics in a tertiary referral center, and controls from the same geographical locations. All subjects underwent an overnight polysomnographic study and a multiple sleep latency test.A total of 124 subjects including 56 patients and 68 controls frequency-matched for age and sex were included. Multivariate analysis revealed that patients had significantly shorter total sleep time than controls (p = 0.01), lower sleep efficiency (p = 0.001) and increased REM latency (p = 0.007). In patients, multivariate analysis showed that reduced total sleep time was significantly associated with increased age (p = 0.001) and increased levodopa dose (p = 0.032). The mean Insomnia Severity Index was higher in PD patients (9.0±7.1) compared to controls (3.3±3.9, p<0.001). The mean Epworth Sleepiness Scale score was higher in PD patients (9.3±5.9 vs. 5.7±4.8, p<0.001). Nocturnal arousals, obstructive sleep apnea, periodic leg movements and objective abnormal sleepiness were not increased in our patients.

Conclusions/Significance

Our case-control polysomnographic study, the first-ever performed in an Asian population, revealed altered sleep architecture and reduced sleep in PD patients compared to controls. Reduced total sleep time was associated with increased age and levodopa dose. However, nocturnal arousals, primary sleep disorders and abnormal sleepiness were not increased in our PD patients suggesting that ethnic/genetic differences may be a factor in the pathophysiology of these conditions.     

CDC-42 and RHO-1 coordinate acto-myosin contractility and PAR protein localization during polarity establishment in C. elegans embryos

In C. elegans one-cell embryos, polarity is conventionally defined along the anteroposterior axis by the segregation of partitioning-defective (PAR) proteins into anterior (PAR-3, PAR-6) and posterior (PAR-1, PAR-2) cortical domains. The establishment of PAR asymmetry is coupled with acto-myosin cytoskeleton rearrangements. The small GTPases RHO-1 and CDC-42 are key players in cytoskeletal remodeling and cell polarity in a number of different systems. We investigated the roles of these two GTPases and the RhoGEF ECT-2 in polarity establishment in C. elegans embryos. We show that CDC-42 is required to remove PAR-2 from the cortex at the end of meiosis and to localize PAR-6 to the cortex. By contrast, RHO-1 activity is required to facilitate the segregation of CDC-42 and PAR-6 to the anterior. Loss of RHO-1 activity causes defects in the early organization of the myosin cytoskeleton but does not inhibit segregation of myosin to the anterior. We therefore propose that RHO-1 couples the polarization of the acto-myosin cytoskeleton with the proper segregation of CDC-42, which, in turn, localizes PAR-6 to the anterior cortex.     

Gain of allelic gene expression for IGF-II occurs frequently in Barrett's esophagus

The IGF-II gene normally exhibits genomic imprinting, a DNA modification that allows the expression of only one of the two inherited alleles. With loss of imprinting, there is a gain of allelic gene expression (GOAGE) due to IGF-II being expressed by both alleles. GOAGE for IGF-II has been demonstrated in a number of malignancies and in normal epithelia surrounding malignancies, but not in epithelia without associated neoplasia. We hypothesized that nonneoplastic Barrett's epithelium might have GOAGE for IGF-II that could facilitate its progression to neoplasia. Endoscopic biopsies were obtained from metaplastic esophageal, normal gastric, and normal duodenal epithelia from 43 patients with Barrett's esophagus. Genomic DNA were analyzed using PCR followed by ApaI restriction enzyme digestion or allele-specific PCR to identify an ApaI polymorphism of IGF-II. cDNA from patients with the ApaI polymorphism were analyzed for IGF-II GOAGE using exon connection PCR, followed by a secondary nested PCR and ApaI restriction enzyme digestion. We found that 13 (30%) of 43 samples of Barrett's metaplasia contained the ApaI polymorphism and were thus informative for IGF-II, and sufficient material was available for GOAGE analysis in 9 of those 13 cases. GOAGE for IGF-II was demonstrated in five (56%) of those nine cases. All patients with GOAGE in Barrett's metaplasia also demonstrated GOAGE in the gastric and duodenal epithelia. In contrast, patients without GOAGE in Barrett's metaplasia also had no GOAGE in their gastric and duodenal epithelia. We conclude that in patients with Barrett's esophagus, GOAGE for IGF-II is found frequently in the metaplastic esophageal epithelium as well as in normal gastric and duodenal epithelia.     

Characterization of dimer subunits of intermediate filament proteins

The fundamental subunit of the various types of intermediate-sized filaments (IF) has been shown to be a tetramer that is thought to represent a double dimer, i.e. an array of two laterally packed coiled-coils of alpha-helices. The two-chain state of intact IF proteins had up to this point not been isolated and characterized as has been done for other fibrous alpha-helical coiled-coil proteins. Using buffers containing 3 M-guanidinium hydrochloride we prepared dimers by depolymerization of IF or by reconstitution from fully denatured molecules. Dimers of desmin (from chicken gizzard), vimentin (from bovine lens tissue and cultured human fibroblasts) and the neurofilament protein NF-L (from bovine brain) as well as in vitro formed homodimers of human and rat cytokeratins numbers 8 (A), 18 (D) and 19 ("40K"), are characterized by ultracentrifugation techniques (sedimentation velocity and equilibrium), electron microscopy and chemical cross-linking. The results show that IF proteins from discrete complexes of two polypeptide chains in parallel orientation and probably in coiled-coil configuration, which apparently have a high tendency to further associate into double dimers. Implications of these results for concepts of IF organization and IF protein assembly are discussed.     

Purification and electron microscopic characterization of the membrane subunit (IICB(Glc)) of the Escherichia coli glucose transporter

The glucose transporter of the bacterial phosphotransferase system mediates sugar transport across the cytoplasmic membrane concomitant with sugar phosphorylation. It consists of a cytoplasmic subunit IIA(Glc) and the transmembrane subunit IICB(Glc). IICB(Glc) was purified to homogeneity by urea/alkali washing of membranes and nickel-chelate affinity chromatography. About 1.5 mg highly pure IICB(Glc) representing 77% of the total activity present in the membranes was obtained from 8g (wet weight) of cells. IICB(Glc) was reconstituted into lipid bilayers by temperature-controlled dialysis to yield small 2D crystals and by a rapid detergent-dilution procedure to yield densely packed vesicles. Electron microscopy and digital image processing of the negatively stained 2D crystals revealed a trigonal lattice with a unit cell size of a = b = 14.5 nm. The unit cell morphology exhibited three dimers of IICB(Glc) surrounding the threefold symmetry center. Single particle analysis of IICB(Glc) in proteoliposomes obtained by detergent dialysis also showed predominantly dimeric structures.     

The MMS22L-TONSL complex mediates recovery from replication stress and homologous recombination

Genome integrity is jeopardized each time DNA replication forks stall or collapse. Here we report the identification of a complex composed of MMS22L (C6ORF167) and TONSL (NFKBIL2) that participates in the recovery from replication stress. MMS22L and TONSL are homologous to yeast Mms22 and plant Tonsoku/Brushy1, respectively. MMS22L-TONSL accumulates at regions of ssDNA associated with distressed replication forks or at processed DNA breaks, and its depletion results in high levels of endogenous DNA double-strand breaks caused by an inability to complete DNA synthesis after replication fork collapse. Moreover, cells depleted of MMS22L are highly sensitive to camptothecin,?a topoisomerase I poison that impairs DNA replication progression. Finally, MMS22L and TONSL are necessary for the efficient formation of RAD51 foci after DNA damage, and their depletion impairs homologous recombination. These results indicate that MMS22L and TONSL are genome caretakers that stimulate the recombination-dependent repair of stalled or collapsed replication forks.     

Orally active and brain permeable proline amides as highly selective 5HT2c agonists for the treatment of obesity

Brain-penetrable proline amides were developed as 5HT2c agonists with more than 1000-fold binding selectivity against 5HT2b receptor. After medicinal chemistry optimization and SAR studies, orally active proline amides with robust efficacy in a rodent food intake inhibition model were uncovered.     

Estimating Orangutan Densities Using the Standing Crop and Marked Nest Count Methods: Lessons Learned for Conservation

Reliable estimates of great ape abundance are needed to assess distribution, monitor population status, evaluate conservation tactics, and identify priority populations for conservation. Rather than using direct counts, surveyors often count ape nests. The standing crop nest count (SCNC) method converts the standing stock of nests into animal densities using a set of parameters, including nest decay rate. Nest decay rates vary greatly over space and time, and it takes months to calculate a site-specific value. The marked nest count (MNC) method circumvents this issue and only counts new nests produced during a defined period. We compared orangutan densities calculated by the two methods using data from studies in Sumatra and Kalimantan, Indonesia. We show how animal densities calculated using nest counts should be cautiously interpreted when used to make decisions about management or budget allocation. Even with site-specific decay rates, short studies using the SCNC method may not accurately reflect the current population unless conducted at a scale sufficient to include wide-ranging orangutan movement. Density estimates from short studies using the MNC method were affected by small sample sizes and by orangutan movement. To produce reliable results, the MNC method may require a similar amount of effort as the SCNC method. We suggest a reduced reliance on the traditional line transect surveys in favor of feasible alternative methods when absolute abundance numbers are not necessary or when site-specific nest decay rates are not known. Given funding constraints, aerial surveys, reconnaissance walks, and interview techniques may be more cost-effective means of accomplishing some survey goals.     

A combined defect in the biosynthesis of N- and O-glycans in patients with cutis laxa and neurological involvement: the biochemical characteristics

Based on our preliminary observation of abnormal glycosylation in a cutis laxa patient, nine cutis laxa patients were analyzed for congenital defects of glycosylation (CDG). Isoelectric focusing of plasma transferrin and apolipoproteinC-III showed that three out of nine patients had a defect in the biosynthesis of N-glycans and core 1 mucin type O-glycans, respectively. Mass spectrometric N-glycan analyses revealed a relative increase of glycans lacking sialic acid and glycans lacking sialic acid and galactose residues. Mutation analysis of the fibulin-5 gene (FBLN5), which has been reported in cases of autosomal recessive cutis laxa, revealed no mutations in the patients' DNA. Evidence is presented that extracellular matrix (ECM) proteins of skin are likely to be highly glycosylated with N- and/or mucin type O-glycans by using algorithms for predicting glycosylation. The conclusions in this study were that the clinical phenotype of autosomal recessive cutis laxa seen in three patients is not caused by mutations in the FBLN5 gene. Our findings define a novel form of CDG with cutis laxa and neurological involvement due to a defect in the sialylation and/or galactosylation of N- and O-glycans. Improper glycosylation of ECM proteins of skin may form the pathophysiological basis for the cutis laxa phenotype.     

Properties of the thermostable glutamate dehydrogenase of the mesophilic anaerobe Peptostreptoccus asaccharolyticus purified by a novel method after over-expression in an Escherichia coli host

Peptostreptococcus asaccharolyticus glutamate dehydrogenase (L-glutamate: NAD+ oxidoreductase (deaminating); EC 1.4.1.2) overexpressed in Escherichia coli has been purified by two new methods. Enzyme made by the first method showed remarkable thermophilicity, with a temperature optimum of 60 degrees C, and also thermostability, which suggested the second, simpler method, incorporating a heat step. This produced 94 mg of homogeneous protein per litre culture medium. The basic kinetic parameters for P. asaccharolyticus glutamate dehydrogenase with all substrates are revealed at pH 7.0. The enzyme is highly specific for NAD+, with values for kcat/Km 405 times greater than for NADP+. In the reverse direction of reaction, the kcat/Km value for NADH is almost 1000-fold greater than for NADPH.