Short telomere length is associated with impaired cognitive performance in European ancestry cohorts.

The association between telomere length (TL) dynamics on cognitive performance over the life-course is not well understood. This study meta-analyses observational and causal associations between TL and six cognitive traits, with stratifications on APOE genotype, in a Mendelian Randomization (MR) framework. Twelve European cohorts (N=17 052; mean age=59.2±8.8 years) provided results for associations between qPCR-measured TL (T/S-ratio scale) and general cognitive function, mini-mental state exam (MMSE), processing speed by digit symbol substitution test (DSST), visuospatial functioning, memory and executive functioning (STROOP). In addition, a genetic risk score (GRS) for TL including seven known genetic variants for TL was calculated, and used in associations with cognitive traits as outcomes in all cohorts. Observational analyses showed that longer telomeres were associated with better scores on DSST (ß=0.051 per s.d.-increase of TL; 95% confidence interval (CI): 0.024, 0.077; P=0.0002), and MMSE (ß=0.025; 95% CI: 0.002, 0.047; P=0.03), and faster STROOP (ß=-0.053; 95% CI: -0.087, -0.018; P=0.003). Effects for DSST were stronger in APOE ɛ4 non-carriers (ß=0.081; 95% CI: 0.045, 0.117; P=1.0 × 10-5), whereas carriers performed better in STROOP (ß=-0.074; 95% CI: -0.140, -0.009; P=0.03). Causal associations were found for STROOP only (ß=-0.598 per s.d.-increase of TL; 95% CI: -1.125, -0.072; P=0.026), with a larger effect in ɛ4-carriers (ß=-0.699; 95% CI: -1.330, -0.069; P=0.03). Two-sample replication analyses using CHARGE summary statistics showed causal effects between TL and general cognitive function and DSST, but not with STROOP. In conclusion, we suggest causal effects from longer TL on better cognitive performance, where APOE ɛ4-carriers might be at differential risk.

Comprehensive Discovery and Quantitation of Protein Heterogeneity via LC-MS/MS Peptide Mapping for Clone Selection of a Therapeutic Protein.

Development of biopharmaceutical production cell lines requires efficient screening methods to select the host cell line and final production clone. This is often complicated by an incomplete understanding of the relationship between protein heterogeneity and function at early stages of product development. LC-MS/MS peptide mapping is well suited to the discovery and quantitation of protein heterogeneity; however, the intense hands-on time required to generate and analyze LC-MS/MS data typically accommodates only smaller sample sets at later stages of clone selection. Here we describe a simple approach to peptide mapping designed for large sample sets that includes higher-throughput sample preparation and automated data analysis. This approach allows for the inclusion of orthogonal protease digestions and multiple replicates of an assay control that encode an assessment of accuracy and precision into the data, significantly simplifying the identification of true-positive annotations in the LC-MS/MS results. This methodology was used to comprehensively identify and quantify glycosylation, degradation, unexpected post-translational modifications, and three types of sequence variants in a previously uncharacterized non-mAb protein therapeutic expressed in approximately 100 clones from three host cell lines. Several product quality risks were identified allowing for a more informed selection of the production clone. Moreover, the variability inherent in this unique sample set provides important structure/function information to support quality attribute identification and criticality assessments, two key components of Quality by Design.

Attention deficits detected in cognitive tests differentiate between sleep apnea patients with or without a motor vehicle accident.

OBJECTIVES: Obstructive sleep apnea (OSA) is associated with an increased motor vehicle accident (MVA) risk. Conventional measures of OSA severity do not predict individual risk. Cognitive function tests have failed to incorporate outcomes in risk prediction. We aimed to identify markers of cognitive function for MVA risk prediction in OSA. METHODS: OSA patients [n = 114, 75% male, median age 51 (43-61) years, body mass index (BMI) 30 (27-33) kg/m2, apnea-hypopnea index 25 (6-49) n/h, and Epworth Sleepiness (ESS) score 11 (8-16)] were recruited from a sleep laboratory. Two cognitive function tests, the Attention Network Test (ANT) and a modified Oxford Sleep Resistance Test (OSLER) test (GOSLING), were assessed. RESULTS: OSA patients with (n = 11) or without (n = 103) a MVA record in the Swedish traffic accident registry were identified. In patients with a MVA, 64% were commercial drivers. In patients with a MVA history, more lapses [42 (5-121) vs. 5 (1-25), P = 0.02] and fewer responses [238 (158-272) vs. 271 (256-277), P = 0.03] to stimuli in the ANT were found. In the GOSLING, the number of lapses was higher (29 (10-97) vs. 7 (2-19), P = 0.01) and the reaction time was longer [462 (393-551) vs. 407 (361-449) ms, P = 0.05]. OSA severity and ESS score poorly predicted MVAs (P > 0.2). CONCLUSIONS: We have demonstrated that deficit in sustained attention, assessed by daytime neurocognitive function tests, was associated with MVA risk in OSA patients. We were unable to detect an association between MVA history and severity of OSA or the ESS score. The findings provide a rationale for further development of objective MVA risk assessment tools in OSA.

Protein mimicry of DNA from crystal structures of the uracil-DNA glycosylase inhibitor protein and its complex with Escherichia coli uracil-DNA glycosylase.

Uracil-DNA glycosylase (UDG), which is a critical enzyme in DNA base-excision repair that recognizes and removes uracil from DNA, is specifically and irreversably inhibited by the thermostable uracil-DNA glycosylase inhibitor protein (Ugi). A paradox for the highly specific Ugi inhibition of UDG is how Ugi can successfully mimic DNA backbone interactions for UDG without resulting in significant cross-reactivity with numerous other enzymes that possess DNA backbone binding affinity. High-resolution X-ray crystal structures of Ugi both free and in complex with wild-type and the functionally defective His187Asp mutant Escherichia coli UDGs reveal the detailed molecular basis for duplex DNA backbone mimicry by Ugi. The overall shape and charge distribution of Ugi most closely resembles a midpoint in a trajectory between B-form DNA and the kinked DNA observed in UDG:DNA product complexes. Thus, Ugi targets the mechanism of uracil flipping by UDG and appears to be a transition-state mimic for UDG-flipping of uracil nucleotides from DNA. Essentially all the exquisite shape, electrostatic and hydrophobic complementarity for the high-affinity UDG-Ugi interaction is pre-existing, except for a key flip of the Ugi Gln19 carbonyl group and Glu20 side-chain, which is triggered by the formation of the complex. Conformational changes between unbound Ugi and Ugi complexed with UDG involve the beta-zipper structural motif, which we have named for the reversible pairing observed between intramolecular beta-strands. A similar beta-zipper is observed in the conversion between the open and closed forms of UDG. The combination of extremely high levels of pre-existing structural complementarity to DNA binding features specific to UDG with key local conformational changes in Ugi resolves the UDG-Ugi paradox and suggests a potentially general structural solution to the formation of very high affinity DNA enzyme-inhibitor complexes that avoid cross- reactivity.

Clinical and radiologic evaluation reveals high prevalence of abnormalities in young adults with dysphagia.

The purpose of this study was to retrospectively evaluate the radiologic findings in young adults with dysphagia undergoing barium swallow and to compare these with the final clinical diagnosis. Clinical history, barium swallow, endoscopy (21 patients), manometry (18 patients), 24 h pH monitoring (4 patients), and outcome of treatments were studied and compared in 43 patients aged 14-30 years (mean 24 years). There were 26 men and 17 women. Duration of symptoms varied between 2 weeks and 22 years and included globus (n = 22), obstruction (n = 31), water brash (n = 6), classic reflux symptoms (n = 10), atypical reflux symptoms (n = 9), slow eating (n = 6), and vomiting (n = 11). The final diagnosis was achalasia (n = 2), arteria lusoria (n = 1), esophagitis (n = 1), esophageal dysfunction (n = 11), esophageal stricture (n = 5), gastroesophageal reflux disease (n = 8), and pharyngeal dysfunction (n = 2). Thirteen patients were assessed to be normal. The result of the barium swallow was in agreement with the final diagnosis in all but 3 patients who were assessed as normal, and the final diagnosis was esophagitis (n = 1), dysmotility (n = 1), and reflux disease (n = 1). Anatomic and functional abnormalities are common in young adults with dysphagia. Barium swallow reveals the explanation of the symptoms in 70% of such patients. Radiology therefore should be the method of choice for the investigation of dysphagic young adults.

Why some capuchin monkeys (Cebus apella) use probing tools (and others do not).

Tufted capuchins (Cebus apella) were provided with a task that facilitated the use and modification of sticks as probing tools. It was found that subjects aged 10 years or older at initial task exposure were less likely to use tools than were younger subjects. Furthermore, juveniles whose mothers died before the subjects were aged 3 years were less likely to use tools than were juveniles whose mothers survived through this period. The ability to use tools was not related to subject sex or to access to the tool site or raw tool materials. Subjects modified tools both before and during their use, and the relative percentage of tools modified increased with subject age. Thus, it appears that capuchins most readily acquire tool use before the age of 10 years and that early disruption of the mother-infant relationship has deleterious effects on the emergence of instrumental behavior.

Site-directed mutagenesis and characterization of uracil-DNA glycosylase inhibitor protein. Role of specific carboxylic amino acids in complex formation with Escherichia coli uracil-DNA glycosylase.

Bacteriophage PBS2 uracil-DNA glycosylase inhibitor (Ugi) protein inactivates uracil-DNA glycosylase (Ung) by acting as a DNA mimic to bind Ung in an irreversible complex. Seven mutant Ugi proteins (E20I, E27A, E28L, E30L, E31L, D61G, and E78V) were created to assess the role of various negatively charged residues in the binding mechanism. Each mutant Ugi protein was purified and characterized with respect to inhibitor activity and Ung binding properties relative to the wild type Ugi. Analysis of the Ugi protein solution structures by nuclear magnetic resonance indicated that the mutant Ugi proteins were folded into the same general conformation as wild type Ugi. All seven of the Ugi proteins were capable of forming a Ung.Ugi complex but varied considerably in their individual ability to inhibit Ung activity. Like the wild type Ugi, five of the mutants formed an irreversible complex with Ung; however, the binding of Ugi E20I and E28L to Ung was shown to be reversible. The tertiary structure of [13C,15N]Ugi in complex with Ung was determined by solution state multi-dimensional nuclear magnetic resonance and compared with the unbound Ugi structure. Structural and functional analysis of these proteins have elucidated the two-step mechanism involved in Ung.Ugi association and irreversible complex formation.

Posture and reaching in tufted capuchins (Cebus apella).

This research investigated the effects of posture on lateral bias for food reaching in tufted capuchin monkeys ( Cebus apella ) by comparing hand preferences for quadrupedal and bipedal reaching. Several findings of this investigation warrant discussion. First, we found a population-level bias towards use of the right hand for bipedal reaching but not for quadrupedal reaching. Second, adults exhibited a greater right-hand preference for bipedal reaching than did immatures. Third, subjects showed a greater right-hand preference, and a greater strength of preference independent of direction, for bipedal reaching than for quadrupedal reaching. Fourth, we found a significant positive relation between the direction of hand preference for quadrupedal and bipedal reaching. We believe that capuchins provide an alternative primate model to chimpanzees for the evolution of human bipedalism and right-handedness. One implication of this model is that right-handedness emerged in hominids prior to extensive expansion of brain size and elaboration of material culture.

Acute myelomonocytic leukaemia with infiltrative peripheral neuropathy.

The case of a 71-year-old woman with acute myelomonocytic leukaemia and severe pains in her arms, legs and back during treatment is described. Signs of a generalized polyneuropathy subsequently developed. Autopsy revealed massive leukaemic infiltration of peripheral nerves. Peripheral nerve involvement in acute leukaemia appears to be rare as judged from the very few previously reported cases. The condition should be suspected whenever inexplicable pain problems and signs of peripheral neuropathy occur in patients with acute leukaemia.

Localization of ornithine decarboxylase in the chick embryo during organogenesis.

The localization of ornithine decarboxylase (ODC), a key enzyme in polyamine biosynthesis and thus in cell growth, was determined in the 4.5-day-old chick embryo, using two independent methods of analysis. ODC protein was identified by indirect immunofluorescence with a monospecific ODC antibody, and catalytically active ODC was identified by autoradiography with alpha-(5-3H) difluoromethylornithine. Both methods revealed a basically similar distribution of ODC within the embryo. Among the organs, the brain exhibited the highest ODC levels. ODC levels were also high in spinal cord, mesonephric tubules and heart. Similar levels, but confined to limited areas, were found in liver tissue, head mesenchyme, and the oral and pharyngeal regions. Organs that exhibited high ODC levels are all engaged in rapid growth, as well as in extensive tissue remodeling and differentiation.

Polyamines in early embryonic development: their relationship to nuclear multiplication rate, cell cycle traverse, and nucleolar formation in a dipteran egg.

Polyamine synthesis and accumulation were assessed from fertilization until gastrulation in a dipteran egg (Calliphora erythrocephala Meigen). Spermidine synthesis was activated immediately after fertilization, generating a broad spermidine peak during early cleavage. This period is characterized by the most rapid nuclear multiplication known from animal material. Cleavage consists of nuclear multiplication only, and the egg remains syncytial until gastrulation. After nine synchronous nuclear divisions with a cycle length of 10 min, the cycle length is gradually increased to 20 min during the subsequent four parasynchronous nuclear divisions. The spermidine level decreased in parallel with this decreasing rate of nuclear division. The interphase of the next nuclear cycle is remarkably prolonged and lasts for more than 90 min, i.e., until after the onset of gastrulation. It consists of an initial short S phase followed by a longer G2 phase; G1 is extremely short or absent. During this prolonged interphase, spermidine content showed a biphasic pattern of changes with peaks during S and late G2. The S-phase peak also coincides with the first appearance of nucleoli during embryogenesis. The late-G2-phase peak coincides with the period of rapid cytokinesis, during which all nuclei in the peripheral layer of the syncytium become separated by membranes forming a cellular blastoderm. The polyamine pattern is consistent with the idea that the polyamines play an important role in DNA replication and in cytokinesis as well as in nucleolar formation.

Plasma carboxypeptidase activity and intolerance to acetylsalicylic acid unimpaired CP-N activity in ASA-intolerant individuals.

Carboxypeptidase N (EC 3.4.17.3, arginine carboxypeptidase, kininase, anaphylatoxin inactivator) activity was determined in human sera with the method of Erdös by differential spectrometry at 254 nm and 37 degrees C, using hippuryl-L-argininic acid (HLAa) as a substrate. Day-to-day imprecision (CV) of the assay was 6.5%. The reference value, as determined in 15 healthy blood donors, was 3,082 +/- 432 IU/1. The mean value in a pool of sera from 12 healthy pregnant women, 4,500 +/- 294 IU/1, was higher in accordance with earlier findings by Erdös et al. Sera from 53 patients with chronic asthma or chronic urticaria, without known acetylsalicylic acid (ASA) intolerance, gave the mean value of 3,583 +/- 768 IU/1, and those from 17 patients with chronic asthma or chronic urticaria and ASA intolerance 3,379 +/- 575 IU/1. Thus, the carboxypeptidase-N activity in the blood of ASA-intolerant asthmatics and urticaria patients was unimpaired. A 16-year-old boy with asthma and without ASA intolerance showed an unusually low value of 2,056 IU/1.

Polar granules and pole cells in the embryo of Calliphora erythrocephala: ultrastructure and [3H]leucine labelling.

The polar granules in Calliphora undergo a gradual fragmentation during early cleavage, but reaggregate after pole-cell formation. Autoradiographic analysis showed that the pole cells in Calliphora acquire a higher [3H]leucine label than the rest of the embryo during the blastoderm stage. Such an increased label was not seen in the pole plasm before pole-cell formation or in the pole cells during gastrulation. Electron microscopic autoradiography revealed that the polar granules are substantially labelled during the blastoderm stage. At the same time, characteristic nuclear blebs appear in the pole cells. The observations are consistent with the hypothesis that polar granules contain maternal messenger RNA, which is released and translated into proteins.