Cardiorespiratory fitness, hippocampal volume, and frequency of forgetting in older adults.

Objective: The purpose of this study was to extend our earlier work to determine the extent to which cardiorespiratory fitness is associated with the frequency of memory problems via its effects on the hippocampus and spatial working memory. We hypothesized that age, sex, education, body composition, and physical activity were direct determinants of fitness, which, in turn, influenced frequency of forgetting indirectly through hippocampal volume and spatial working memory. Method: We conducted assessments of demographic characteristics, Body Mass Index (BMI), physical activity, cardiorespiratory fitness, hippocampal volume, spatial working memory, and frequency of forgetting in 158 older adults (M age = 66.49). Path analyses within a covariance modeling framework were used to examine relationships among these constructs. Results: Sex, age, BMI, and education were all significant determinants of cardiorespiratory fitness. The hypothesized path models for testing the effects of fitness on frequency of forgetting through hippocampal volume and accuracy and speed of spatial working memory all fit the data well. Conclusions: Our findings suggest that older adults with higher levels of fitness show greater preservation of hippocampal volume, which, in turn, is associated with more accurate and faster spatial memory and fewer episodes of forgetting. Given the proportion of older adults reporting memory problems, it is necessary to determine whether improvements in fitness brought about by physical activity interventions can result in subsequent attenuation of memory problems or potentially in improvements in memory. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Self-citation: comparison between Radiology,European Radiology and Radiology for 1997–1998

This study investigates the incidence of self-citation (authors citing their own work) for scholarly articles in ten journals published by the American Physiological Society. We analysed authorship and referencing practices of all original research articles published in the first ordinary issue of each journal in both 2000 and 2010, comprising 271 and 212 articles, respectively. Self-citation is common in these journals and represents a total of 17.75% of all citations. Only 9 (1.86%) of the articles analysed did not self-cite. Author position significantly influenced the rate of self-citation with last authors being self-cited significantly more than any other author. This was likely a result of the cumulative nature of scientific research within a specific discipline and the necessary desire to promote ones own work for associated academic benefit. The country in which the work was conducted also influenced the rate of self-citation, with last authors based in North America self-citing more than last authors from Asian countries. A comparison of self-citation rates between decades (2000 and 2010) revealed an increase in the number of authors and number of citations per article between 2000 and 2010, however the mean percentage of self-cited articles did not differ between the years. Finally, there were no differences in the percentage of self-citation between the different journals analysed.     

Hydrolyzed fumonisins HFB1 and HFB2 are acylated in vitro and in vivo by ceramide synthase to form cytotoxic N-acyl-metabolites

Fumonisins B1 and B2 (FB1 and FB2) are the most abundant members of the fumonisins--mycotoxins that are produced by Fusarium verticillioides and are natural inhibitors of ceramide synthase. Their hydrolyzed forms, HFB1 and HFB2 (also called AP1 and AP2) are found in some foods, and they are not only inhibitors of ceramide synthase but also undergo acylation by this enzyme. This study characterized the conversion of HFB1 and HFB2 by ceramide synthase to their respective N-acylated metabolites using rat liver microsomes and palmitoyl-CoA or nervonoyl-CoA as cosubstrates, and examined animals that had been dosed with hydrolyzed fumonisins to ascertain if acylation occurs in vivo. Using an HPLC-MS/MS method that allowed the sensitive and selective detection of the acylation products, both HFB1 and HFB2 were found to be metabolized in vitro to nervonoyl- or palmitoyl-HFB1 and -HFB2 (i.e. C24:1-HFB1/2 and C16-HFB1/2, respectively). The apparent vmax was considerably higher for formation of C24:1HFB1 (157 pmol/min/mg protein) than for formation of C16HFB1 (8.7 pmol/min/mg protein). The acylation products also inhibited ceramide synthase and significantly reduced the number of viable cells in an in vitro [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)] assay using a human colonic cell line (HT29). Furthermore, HPLC-MS/MS analysis of tissues from rats given intraperitoneal doses of HFB1 confirmed that formation of N-acyl-HFB1 occurs in vivo to produce metabolites with fatty acids of various chain lengths. The contribution of acylated HFB1 and HFB2 metabolites to fumonisin toxicity in vivo warrants further investigation.     

Free choice systems have home states

Summary This paper contains a proof that live and safe free choice Petri nets have home states. Home states are ones which can be reached from every successor state of the initial state. Liveness means that all actions remain executable, and safeness means that all capacities are finite. The result is interesting because it may help in the analysis of behavioural properties of complex systems. The existence of home states is a strong property which (as we will also show) fails to hold for a slightly generalised class of nets.     

Traumatic duodenal haematoma in children

A clinical study of 96 patients compared a new hydrocolloid dressing (Granuflex Extra Thin) with a non-adherent dressing (perforated film absorbent dressing) in the management of lacerations, abrasions and minor operation incisions at the Accident and Emergency (A&E) Department of the University College Hospital, Galway. While time to heal was similar for both groups, the patients using Granuflex Extra Thin experienced less pain (P < 0.001), required less analgesia (P = 0.0154) and were able to carry out their normal daily activities including bathing or showering without affecting the dressing or the wound. Patient satisfaction with the new dressing appeared to be very high especially in those patients who pursued an active lifestyle.     

Invariant fitting of planar objects by primitives

The determination of invariant characteristics is an important problem in pattern recognition. Many invariants are known which have been obtained by the method of normalization. In this paper, we introduce a new approach of fitting planar objects by primitives using the method of normalization (e.g., fitting by lines, triangles, rectangles, circles, ellipses, super-quadrics, etc.). Objects and primitives are described by features, for example, by moments. The main advantage is that the normalization process provides us with a canonical frame of the object and the primitive. Therefore, the fit is invariant with respect to the transformation used. By this new method, an analytical fitting of non-analytical objects can be achieved, for example, fitting by polygons. Furthermore, the numerical effort can be reduced drastically by normalizing of the object and the primitive     

Investigation of the sequence of colonization and candidemia in nonneutropenic patients

Among neutropenic patients with hematologic malignancies, candidemia has been shown to arise typically from autoinfection after colonization. In patients without neutropenia, we examined the similarities of strains colonizing or infecting various body sites and those subsequently causing Candida bloodstream infections. Strain similarity was examined by karyotyping and restriction endonuclease analysis of genomic DNA (REAG) by using two restriction enzymes (SfiI and BssHII). The banding patterns of 42 isolates from 19 patients were independently evaluated in a blinded fashion by three observers. The interobserver reliability measured with a generalized kappa statistic was 0.59 for karyotyping, 0.84 for REAG with SfiI, and 0.88 for REAG with BssHII (P < 0.001 for each). REAG classified the initial colonizing or infecting isolate and subsequent blood isolates as identical in 16 patients (84%). The mean duration of colonization or infection prior to a positive blood culture was 5 and 23 days in patients infected with related and unrelated isolates, respectively (P = 0.14; 95% confidence interval = -14.5 to 50.5). Karyotyping results matched the REAG results for isolates from 14 of the 19 patients (74%). In patients infected with identical isolates, the initial isolate was most frequently recovered from the urine (n = 5) or vascular catheter tips (n = 4). In the five subjects with organisms showing disparate results between the methods, karyotyping revealed different banding patterns, whereas REAG suggested that the isolates were identical. Candida colonization or infection with an identical strain frequently precedes bloodstream infection in nonneutropenic patients. Future studies should evaluate whether patients at high risk for candidemia and who have vascular catheter or urine samples that are positive for a Candida on culture should be treated empirically.     

Fathers and breast feeding: a pilot observational study

A small pilot survey (n = 113) by questionnaire of the fathers of a sample of children under one year of age was undertaken in order to investigate the involvement of fathers with infant feeding and their attitudes to the method of feeding adopted. The response rate was 72% overall and 79% when the partners of 'single parent' mothers were excluded. Nearly 30% of respondents had not discussed the method of feeding with anyone, but over 60% had discussed it with their partner. 64% of fathers sometimes helped with feeding their child and 17% said that they always helped. The majority of fathers did not mind their partner breast feeding in front of friends or relatives but 42% did not like them feeding in front of strangers and over half did not like them breast feeding in a public place. From this study, based on relatively small numbers, we conclude that fathers may feel left out of infant feeding. They should be given more opportunity to become involved from an early stage and take part in the decision about the method of infant feeding to be adopted.     

Phenytoin blocks the reversal of a classically conditioned discriminative eyeblink response in rabbits

The aim of the present study was to assess the role of vascular alpha 1D-adrenoceptors in the sympathetic vasopressor response in vivo. Specifically, we evaluated the effect of a selective alpha 1D-adrenoceptor antagonist, BMY 7378 (8-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-8-azaspiro(4,5)dec ane-7,9- dione 2HCl), on the vasopressor response induced by preganglionic (T7-T9) sympathetic stimulation in the pithed rat. The vasopressor response was dose-dependently sensitive to inhibition by intravenous BMY 7378 (0.1, 0.31, 1 and 3.1 mg/kg), doses of 1 and 3.1 mg/kg being equally effective. Like BMY 7378, 5-methylurapidil (0.1, 0.31, 1 and 3.1 mg/kg) antagonized the vasopressor response to spinal stimulation; doses of 1 and 3.1 mg/kg were also equally effective. In combination experiments, BMY 7378 (1 mg/kg, i.v.) and the alpha 1A-adrenoceptor antagonist, 5-methylurapidil (1 mg/kg, i.v.), showed an additive effect. The present results demonstrate that the alpha 1D-adrenoceptor subtype plays an important role in the pressor response to sympathetic nerve stimulation in the pithed rat, and confirm the participation of the alpha 1A-adrenoceptor subtype in the same response.