PNP
Purine nucleoside phosphorylase (EC 2.4.2.1) (PNP) (Inosine phosphorylase) (Inosine-guanosine phosphorylase) [NP]
PublicationsПравить
Increasing attention is payed to the contribution of somatosensory processing in motor control. In particular, temporal somatosensory discrimination has been found to be altered differentially in common movement disorders. To date, there have only been speculations as to how impaired temporal discrimination and clinical motor signs may relate to each other. Prior to disentangling this relationship, potential confounders of temporal discrimination, in particular age and peripheral nerve conduction, should be assessed, and a quantifiable measure of proprioceptive performance should be established. To assess the influence of age and polyneuropathy (PNP) on somatosensory temporal discrimination threshold (STDT), temporal discrimination movement threshold (TDMT), and behavioral measures of proprioception of upper and lower limbs. STDT and TDMT were assessed in 79 subjects (54 healthy, 25 with PNP; age 30-79 years). STDT was tested with surface electrodes over the thenar or dorsal foot region. TDMT was probed with needle electrodes in flexor carpi radialis (FCR) and tibialis anterior (TA) muscle. Goniometer-based devices were used to assess limb proprioception during (i) active pointing to LED markers, (ii) active movements in response to variable visual cues, and (iii) estimation of limb position following passive movements. Pointing (or estimation) error was taken as a measure of proprioceptive performance. In healthy subjects, higher age was associated with higher STDT and TDMT at upper and lower extremities, while age did not correlate with proprioceptive performance. Patients with PNP showed higher STDT and TDMT values and decreased proprioceptive performance in active pointing tasks compared to matched healthy subjects. As an additional finding, there was a significant correlation between performance in active pointing tasks and temporal discrimination thresholds. Given their notable impact on measures of temporal discrimination, age and peripheral nerve conduction need to be accounted for if STDT and TDMT are applied in patients with movement disorders. As a side observation, the correlation between measures of proprioception and temporal discrimination may prompt further studies on the presumptive link between these two domains.
Keywords
- TDMT
- aging
- kinesthesia
- pointing task
- position estimation
- somatosensory temporal discrimination
- temporal discrimination threshold
Obesity and its complications are prevalent in women and increase with age. Polyneuropathy (PNP) is a complication of obesity and bariatric surgery (BS). In subjects with severe (grades II and III) obesity and without DM who are candidates for BS, the prevalence of PNP and associated conditions are not well characterized. The aim of this study was to evaluate the prevalence of PNP in severely obese (SO) women without DM or common nutritional deficiencies in order to determine factors associated with the presence of PNP. A cross-sectional study was performed on 450 SO women. They were evaluated with the Michigan Neuropathy Screening Instrument, a Sleep Apnea Questionnaire, and the short form of the International Physical Activity Questionnaire. Data on blood pressure, body mass index, waist circumference, serum glucose, glycated hemoglobin, LDL and HDL cholesterol, triglycerides, vitamin B12, and postmenopausal (PM) status were also collected. Patients with DM and other common causes of PNP were excluded. To evaluate which variables were independently associated with PNP (dependent variable), Poisson regression models were used. The prevalence of PNP was 11.6%. In univariate analysis, PNP was associated with age, PM status, and diagnosis of systemic arterial hypertension (p < 0.001, p < 0.001, and p = 0.016, respectively), and there was a trend toward an association with sleep apnea risk (p = 0.101). In multivariate analysis, PM status (PR = 2.836, 95% CI 1.735-4.636, p = 0.001) and age (PR = 1.0511, 95% CI 1.031-1.071, p = 0.001) were independently associated with PNP diagnosis in two different models. Even prior to BS, PNP is highly prevalent and is associated with PM status and age in SO women without diabetes.
MeSH Terms
- Adult
- Cross-Sectional Studies
- Deficiency Diseases
- Diabetes Mellitus
- Female
- Humans
- Michigan
- Obesity, Morbid
- Polyneuropathies
- Prevalence
- Risk Factors
Keywords
- Aging
- Bariatric surgery
- Polyneuropathy
- Postmenopause
- Severe obesity
Young adults show consistent neural benefits of predictable contexts when processing upcoming words, but these benefits are less clear-cut in older adults. Here we disentangle the neural correlates of prediction accuracy and contextual support during word processing, in order to test current theories that suggest that neural mechanisms underlying predictive processing are specifically impaired in older adults. During a sentence comprehension task, older and younger readers were asked to predict passage-final words and report the accuracy of these predictions. Age-related reductions were observed for N250 and N400 effects of prediction accuracy, as well as for N400 effects of contextual support independent of prediction accuracy. Furthermore, temporal primacy of predictive processing (i.e., earlier facilitation for successful predictions) was preserved across the lifespan, suggesting that predictive mechanisms are unlikely to be uniquely impaired in older adults. In addition, older adults showed prediction effects on frontal post-N400 positivities (PNPs) that were similar in amplitude to PNPs in young adults. Previous research has shown correlations between verbal fluency and lexical prediction in older adult readers, suggesting that the production system may be linked to capacity for lexical prediction, especially in aging. The current study suggests that verbal fluency modulates PNP effects of contextual support, but not prediction accuracy. Taken together, our findings suggest that aging does not result in specific declines in lexical prediction.
MeSH Terms
- Adolescent
- Adult
- Aged
- Aging
- Anticipation, Psychological
- Brain Mapping
- Comprehension
- Electroencephalography
- Evoked Potentials
- Female
- Humans
- Male
- Middle Aged
- Photic Stimulation
- Principal Component Analysis
- Reaction Time
- Reading
- Semantics
- Time Factors
- Young Adult
Keywords
- Aging
- Contextual Support
- N250
- N400
- Post-N400 positivity
- Prediction
- Reading
Aspiration pneumonia (AP) is caused by dysfunctional swallowing resulting in aspiration of material colonized by respiratory pathogens. The aim of this study was to assess and compare the swallowing physiology, health status, oral health status, and oral/nasal microbiota in frail older patients (FOP) with oropharyngeal dysphagia (OD) and a control group. We studied 47 FOP (>70 year) with OD by videofluoroscopy (17 with acute pneumonia -APN-, 15 with prior pneumonia-PNP- and 15 without) and 14 older controls without OD (H). Oral/nasal colonization by five respiratory pathogens was evaluated by qPCR, whereas commensal microbiota composition was assessed by pyrosequencing. (i) Frail older patients with OD presented similar comorbidities, poor functionality, polymedication, and prevalent videofluoroscopic signs of impaired safety of swallow (33.3-61.5%). However, patients with OD-APN also presented malnutrition, delayed laryngeal vestibule closure (409.23 ± 115.6 ms; p < 0.05), and silent aspirations (15.6%). (ii) Oral health was poor in all groups, 90% presented periodontitis and 72%, caries. (iii) Total bacterial load was similar in all groups, but higher in the oropharynx (>10(8) CFU/mL) than in the nose (<10(6) CFU/mL) (p < 0.0001). Colonization by respiratory pathogens was very high: 93% in OD patients (p < 0.05 vs H); 93% in OD-PNP (p < 0.05 vs H); 88% in OD-APN (p = 0.07 vs H), and lower in controls (67%). Frail older patients with OD had impaired health status, poor oral health, high oral bacterial load, and prevalence of oral colonization by respiratory pathogens and VFS signs of impaired safety of swallow, and were therefore at risk for contracting AP.
MeSH Terms
- Aged
- Aged, 80 and over
- Deglutition Disorders
- Female
- Frail Elderly
- Humans
- Male
- Mouth
- Nose
- Pneumonia, Aspiration
- Prevalence
Keywords
- aspiration pneumonia
- geriatrics
- oral microbiota
- respiratory pathogens
- swallowing disorders