Effects of surface irregularity and lighting on step variability during gait: a study in healthy young and older women

Relatively few studies have examined how uneven surfaces affect human gait. To study this, along with the effects of advancing age and low light conditions, we measured step width and step time variability, as well as comfortable gait speed, in 12 healthy young women (YW) and 12 healthy older women (OW) as they walked at a comfortable speed along a 10-m walkway. Ten trials were completed for each cell of a 2 x 2 factorial design: (1) flat surface with regular lighting; (2) flat surface with low lighting; (3) irregular surface with regular lighting; and (4) irregular surface with low lighting. Effects of surface type, incident lighting, and age on gait parameters were tested via repeated measures ANOVA. Surface type significantly affected step width variability (P < 0.001) and step time variability (P < 0.001). Light level showed no significant effect on any of the gait parameters. One significant age group difference was found: step width variability was significantly greater in OW than YW (P = 0.010). We conclude that the irregular surface had a greater effect on the gait variability of healthy OW than on that of healthy YW.     

Influence of an irregular surface and low light on the step variability of patients with peripheral neuropathy during level gait

Patients with peripheral neuropathy (PN) report greater difficulty walking on irregular surfaces with low light (IL) than on flat surfaces with regular lighting (FR). We tested the primary hypothesis that older PN patients would demonstrate greater step width and step width variability under IL conditions than under FR conditions. Forty-two subjects (22 male, 20 female: mean +/- S.D.: 64.7 +/- 9.8 years) with PN underwent history, physical examination, and electrodiagnostic testing. Subjects were asked to walk 10 m at a comfortable speed while kinematic and force data were measured at 100 Hz using optoelectronic markers and foot switches. Ten trials were conducted under both IL and FR conditions. Step width, time, length, and speed were calculated with a MATLAB algorithm, with the standard deviation serving as the measure of variability. The results showed that under IL, as compared to FR, conditions subjects demonstrated greater step width (197.1 +/- 40.8 mm versus 180.5 +/- 32.4 mm; P < 0.001) and step width variability (40.4 +/- 9.0 mm versus 34.5 +/- 8.4 mm; P < 0.001), step time and its variability (P < 0.001 and P = 0.003, respectively), and step length variability (P < 0.001). Average step length and gait speed decreased under IL conditions (P < 0.001 for both). Step width variability and step time variability correlated best under IL conditions with a clinical measure of PN severity and fall history, respectively. We conclude that IL conditions cause PN patients to increase the variability of their step width and other gait parameters.     

Carnosine as a protective factor in diabetic nephropathy: association with a leucine repeat of the carnosinase gene CNDP1

The risk of diabetic nephropathy is partially genetically determined. Diabetic nephropathy is linked to a gene locus on chromosome 18q22.3-q23. We aimed to identify the causative gene on chromosome 18 and to study the mechanism by which the product of this gene could be involved in the development of diabetic nephropathy. DNA polymorphisms were determined in 135 case (diabetic nephropathy) and 107 control (diabetes without nephropathy) subjects. The effect of carnosine on the production of extracellular matrix components and transforming growth factor-beta (TGF-beta) after exposure to 5 and 25 mmol/l d-glucose was studied in cultured human podocytes and mesangial cells, respectively. A trinucleotide repeat in exon 2 of the CNDP1 gene, coding for a leucine repeat in the leader peptide of the carnosinase-1 precursor, was associated with nephropathy. The shortest allelic form (CNDP1 Mannheim) was more common in the absence of nephropathy (P = 0.0028, odds ratio 2.56 [95% CI 1.36-4.84]) and was associated with lower serum carnosinase levels. Carnosine inhibited the increased production of fibronectin and collagen type VI in podocytes and the increased production of TGF-beta in mesangial cells induced by 25 mmol/l glucose. Diabetic patients with the CNDP1 Mannheim variant are less susceptible for nephropathy. Carnosine protects against the adverse effects of high glucose levels on renal cells.     

Adverse effect of high added sugar consumption on dietary intake in American preschoolers

OBJECTIVES: To assess the effect of Dietary Reference Intakes (DRI)-recommended added sugar intake levels on nutrient and food group consumption by preschoolers. STUDY DESIGN: This was a cross-sectional study of 2- to 5-year-olds in the United States Department of Agriculture Continuing Survey of Food Intake by Individuals (CSFII), 1994 to 1996, and 1998 (n = 5437). Main food sources of added sugar were established. For five categories (< or =10% energy from added sugar, 11% to 15%, 16% to 20%, 21% to 25%, and >25%), mean nutrient and food group consumption and proportion of children not meeting the DRI were ascertained. The nonparametric test for trend indicated significance of changes. Analysis was stratified by age (2- to 3-year-olds versus 4- to 5-year-olds), and survey design corrected to maintain the nationally representative character of the data. RESULTS: The majority of children consumed less than 25% of energy from added sugar; the main sources were fruit and or soft drinks and desserts. Increasing added sugar consumption was paralleled by decreasing nutrient and food group intakes and increasing proportions of children with intakes below the DRI. Calcium intake was insufficient in large proportions of children consuming 16% or more from added sugar. CONCLUSIONS: In preschoolers, the new DRI for added sugar are reason for concern. Further research is needed to investigate the effects of the DRI on diet quality, body weight, and health status in young children.     

Cholesterol 25-hydroxylase on chromosome 10q is a susceptibility gene for sporadic Alzheimer's disease

Alzheimer's disease (AD) is the most common cause of dementia. It is characterized by beta-amyloid (A beta) plaques, neurofibrillary tangles and the degeneration of specifically vulnerable brain neurons. We observed high expression of the cholesterol 25-hydroxylase (CH25H) gene in specifically vulnerable brain regions of AD patients. CH25H maps to a region within 10q23 that has been previously linked to sporadic AD. Sequencing of the 5' region of CH25H revealed three common haplotypes, CH25Hchi2, CH25Hchi3 and CH25Hchi4; CSF levels of the cholesterol precursor lathosterol were higher in carriers of the CH25Hchi4 haplotype. In 1,282 patients with AD and 1,312 healthy control subjects from five independent populations, a common variation in the vicinity of CH25H was significantly associated with the risk for sporadic AD (p = 0.006). Quantitative neuropathology of brains from elderly non-demented subjects showed brain A beta deposits in carriers of CH25Hchi4 and CH25Hchi3 haplotypes, whereas no A beta deposits were present in CH25Hchi2 carriers. Together, these results are compatible with a role of CH25Hchi4 as a putative susceptibility factor for sporadic AD; they may explain part of the linkage of chromosome 10 markers with sporadic AD, and they suggest the possibility that CH25H polymorphisms are associated with different rates of brain A beta deposition.     

Effects of ethnicity and gender on motion sickness susceptibility

INTRODUCTION: Susceptibility to motion sickness (MS) is known to be affected by gender and ethnic origin, but whether gender and ethnicity are interacting is unknown. METHODS: We investigated MS development in healthy Caucasian subjects (n = 227), and in subjects of Chinese origin (n = 82). All subjects were exposed to nausea-inducing body rotations in a rotation chair, and rotated around the yaw axis for 5 x 1 min, while they were instructed to move their heads. Prior to rotation, subjects had to fill out a motion-sickness susceptibility questionnaire (MSSQ). Total rotation tolerance time (RT) was noted. Symptom ratings (SR) were performed at the beginning, and immediately after the end of each rotation, and 15 and 30 min later. RESULTS: The average RT was significantly higher in Caucasian (163 +/- 6 s) than in Chinese subjects (111 +/- 7 s) (F = 24.84, p < 0.0001). The adult MSSQ score was significantly lower in Caucasians (17.8 +/- 1.1) than in Chinese volunteers (24.2 +/- 2.1) (F = 6.05, p = 0.014). Maximal SR post rotation was similar in Chinese and Caucasian subjects. RT was highly predictable from the MSSQ scores, but separate for both genders. CONCLUSION: Susceptibility to MS is affected by both ethnic origin and by gender in a rather complex fashion. The most reliable prediction of RT can be based on the individual's history as assessed by the MSSQ.     

Estimation of postmortem metabolic changes in porcine brain tissue using <Superscript>1</Superscript>H-MR spectroscopy—preliminary results

To investigate the potential for estimating the time since death by monitoring the evolution of different metabolites in brain tissue by ¹H-MRS, an animal model using pig heads was established. The maximum examination interval was 3 weeks. Within this time interval spectra revealed different compositions of metabolites, including metabolites observed in the normal brain and as products of bacterial decomposition processes (N-acetyl-aspartate 0–130 h, creatine 0–170 h, bound trimethylammonium, e. g. choline compounds, during the whole time course with fluctuating intensities, lactate 0–200 h, alanine and acetate during the whole time course, succinate and free trimethylammonium after approx. 100 h postmortem). The proposed approach may offer a new method to estimate later postmortem intervals although these observations have to be confirmed by further studies.