Cuticle chirality and body handedness in Caenorhabditis elegans

BACKGROUND AND PURPOSE: Norway has the highest reported incidence of hip fractures in western Europe. Little is known about the epidemiology of falls in Norway where the winter season is long and dark. The objective of this work was to study reported falls and their consequences among elderly Norwegians living at home. METHODS: A cross-sectional design was used for the study. Interviews were performed in the homes of 431 subjects, aged 67-97 years, living at home. Information on falling was gathered through six questions: whether the subject had fallen during the last six months, and if so, how many falls they had, where the last fall occurred, its perceived reason, the activity the subject had been engaged in when the fall occurred, and the resulting injury. RESULTS: In all, 24.1% of subjects reported falling during the last six months, and 9.5% had suffered more than one fall. Falls were most frequently linked to external events (63.1%). Outdoor falls were more frequent (59.0%; 95% CI = 51.2-82.0) than indoor falls. Older subjects were associated with more frequent indoor falls (p < 0.05), but gender was not significant. Fifty-one per cent of subjects had fallen while walking and 53% had suffered an injury from the last fall. In 13.4% of the women and 16.2% of the men, the last fall had resulted in a fracture. CONCLUSIONS: Compared to the results of other studies from industrialized Western countries, a similar crude fall rate, similar frequency and similar type of injury were found. However, in contrast to other studies, no gender difference was observed with regard to falling, place of falling and fracture rate.     

Attentional control within 3-D space

Four experiments investigated whether directing attention to a particular plane in depth enables observers to filter out information from another depth plane. Observers viewed stereoscopic displays and searched for a red line segment among green line segments. The results showed that directing attention to a particular depth plane cannot prevent attentional capture from another depth plane when the colors of the target and distractor are identical. However, it can prevent attentional capture by a singleton from another depth plane when the colors of the target and distractor are different. These results indicate that only when both color and depth information are selective in guiding attention to the target singleton can attentional capture by irrelevant singletons be prevented. The results also suggest that retinal disparity does not have the same special status as location information in two dimensions and should be considered as just another feature along which selection may occur.     

The effect of dietary fatty acid balance on myocardial lesions in male rats

Three hundred (experiment I) and 350 (experiment II) weanling, 3-week-old male Sprague-Dawley rats weighing between 40–50 g were randomly assigned two per cage and 50 per dietary treatment to study the effect of dietary fatty acid balance on myocardial lesions. The following oils were tested: Experiment I.Brassica napus var. Tower rapeseed oil [Tower RSO, 1974 cultivar and 1975 cultivar, each containing 0.3% erucic (22∶1) acid];B. napus var. Zephyr RSO containing 0.9% 22∶1; corn oil; olive oil; and soybean oil. Experiment II.B. napus var. Tower RSO (1974 cultivar), olive oil, soybean oil, and the following oils to which was added the indicated level of free 22∶1; Tower +0.5% 22∶1; Tower +5.6% 22∶1; olive oil +4.4% 22∶1; soybean oil +5.7% 22∶1. In each case the oils were incorporated in a semisynthetic diet at a level of 20% by weight. Heart and heart lipid weights of rats fed the different oils did not differ statistically from each other. Fatty acid analyses of heart lipids revealed that the fatty acid composition of the cardiac lipids reflected that of the diet fed. In experiment I, there was a definite but significantly lower incidence (P<0.01) and severity (P<0.01) of heart lesions in rats fed control oils (corn, olive, soybean) than in rats fed rapeseed oils. Also, in experiment II, a definite but lower incidence and severity of heart lesions occurred in rats fed control oils (soybean, olive) compared to rats fed Tower RSO or this oil with added free 22∶1. Adding 22∶1 to an oil naturally high in 18∶3 (soybean) did not alter the incidence of heart lesions, whereas adding 22∶1 to an oil naturally high in 18∶1 (olive) increased significantly (P<0.01) both the incidence and severity of heart lesions. Thus, it appears that the background incidence of heart lesions that are found in the rat in any case, and which are increased by rapeseed oil feeding, is caused by the imbalanced fatty acid composition of the oil for the growing rat, i.e. high monoenes (18∶1, 20∶1, and 22∶1) and high 18∶3 and is not only due to the presence of excess 18∶3. Contribution No. 706, Animal Research Institute.     

Thermo-oxidative degradation of polyolefins observed by isothermal long-term DTA

Isothermal differential thermal analysis (DTA) is well known for measuring thermal stability of polyolefins by determining the oxidative induction time at elevated temperatures. Oxidative induction time, measured up to 7,000 hours and over a temperature range from 240°C to 120°C, has been used to study the stability of polybutene-1 and crosslinked polyethylene in the melt state. The Arrhenius plots of DTA results show that straight line extrapolation from high to low temperatures is not possible. Thermoanalytically measured oxidation induction times and mechanical failure in oven aging experiments agree for polybutene and crosslinked polyethylene, Measurements of molecular weight and of mechanical properties of polybutene-1 during the induction period of oven aging experiments at low temperatures revealed that molecular weight and tensile properties are not sensitive indicators for the beginning of aging. The state of deterioration can be estimated easier by measurement of residual lifetime in the isothermal DTA experiment. Diffusion processes of stabilizers in polyolefins, as well as the consumption of stabilizer at elevated temperatures, especially during the induction period also was observed by DTA. Finally the extraction of stabilizer by hot water was measured by isothermal DTA.     

Quantitating heart lipids: Comparison of results obtained using the Iatroscan method with those from phosphorus and gas chromatographic techniques

The precision and accuracy of the Iatroscan method was evaluated by comparing the results obtained with established phosphorus and gas chromatographic techniques. A complete lipid class analysis of rat heart lipids was chosen in order to evaluate the performance of the Iatroscan method for biological samples which contained both neutral lipids and phospholipids. A partial scan and repeat development with chloroform/methanol/water (68.5∶29∶2.5) was introduced to achieve consistently good separations of the phospholipids on the Chromarods in the Iatroscan method. The results showed that the precision of the Iatroscan method for some lipid classes was comparable to that of phosphorus or gas chromatographic techniques, while for other lipid classes it was lower. Compared to the data obtained using the phosphorus method, the Iatroscan data were generally similar, while the gas chromatographic method generally gave lower values. These findings, together with the advantages of time required for analysis, size of sample, and universality of detection, suggest that the Iatroscan is a valuable complementary method for complex lipid analyses.     

Low-field 3-DFT MRI: conceptual, analytical, and experimental aspects

Three-dimensional Fourier transform (3-DFT) magnetic resonance imaging (MRI) offers advantages in terms of signal-to-noise (S/N) per unit of time for the case where a large number of slices is desired. This advantage is enhanced when the relaxation time, T(1 ), is short. Because time limitations in 3-DFT imaging force the use of short time intervals, TR, between excitations of a slice, lesion contrast is often undesirable at mid-and high-field strength even when the S/N is good. At low fields, where T(1) values are short, high S/N and contrast can both be achieved with 3-DFT MR images. The conceptual and analytical aspects of low-field 3-DFT MRI are presented and demonstrated at 640 G.     

Real-time patch-cram detection of intracellular cGMP reveals long-term suppression of responses to NO and muscarinic agonists

Cyclic GMP (cGMP) is a crucial intracellular messenger in neuronal, muscle, and endocrine cells. The intracellular concentration of cGMP is regulated by various neurotransmitters, including acetylcholine (ACh) and nitric oxide (NO). While much is known about the biochemical steps leading to cGMP synthesis, little is known about cGMP kinetics in intact cells. Here, we use "patch-cramming," in which an excised, inside-out membrane patch containing cyclic nucleotide-gated ion channels is used as a biosensor, to obtain the first real-time measurements of cGMP in intact cells. Patch-cramming experiments on neuroblastoma cells show that both muscarinic agonists and NO rapidly elevate cGMP. NO elicits cGMP responses repeatedly without decrement, whereas responses to muscarinic agonists exhibit a profound and prolonged desensitization. Remarkably, muscarinic agonists also cause long-term (>30 min) suppression (LTS) of cGMP responses elicited by NO. Biochemical measurements reveal that rat sympathetic neurons also exhibit LTS of cGMP, suggesting that LTS is a widespread mechanism that may contribute to synaptic plasticity.