Effective lipid lowering diets including lean meat

The plasma lipid and lipoprotein responses to two modified isoenergetic diets including meat were studied in 15 free living men with hyperlipidaemia (mean plasma cholesterol and triglyceride concentrations 8·1 and 3·4 mmol/l). A reference diet (diet A, 42% energy from fat, ratio of polyunsaturated to saturated fatty acids (P:S ratio) 0·2) was compared with a fat reduced diet (diet B, 35% energy from fat, P:S ratio 0·5) and with a further fat modified diet supplemented with fibre (diet C, 27% energy from fat, P:S ratio 1·0). Daily intake of meat and meat products (180 g/day) was the same in each dietary period; that in diet A had a fat content typical of the average British diet, whereas that in diets B and C was based on very lean meat and meat products. During consumption of diet B the plasma cholesterol concentration fell by 8·6% and low density lipoprotein cholesterol by 11%. During consumption of diet C plasma cholesterol fell by 18·5% and low density lipoprotein cholesterol by 23·8%. Triglyceride and high density lipoprotein cholesterol concentrations and body weight did not change appreciably during the study.A modified diet including a moderate amount of lean meat and meat products is compatible with a reduced lipoprotein mediated risk of atherosclerotic heart disease.     

Analysis of dynamic and stationary pattern formation in the cell cortex

We study a sol-gel mechanochemical model for cellular cytoplasm. Using conservation equations and a force balance equation, we derive equations for the sol-gel dynamics. Regular perturbation analysis suggests the growth of patterns which may be either dynamic or stationary, depending on parameter values. Nonlinear analysis, which indicates that these patterns remain bounded, is confirmed by numerically solving the mechanochemical equations. We use these analytical and numerical results to model two different biological problems: the dynamic formation of filopodia in nerve growth cones, and the growth of microvilli in epithelial cells.     

Isolation and mapping of polymorphic cosmid clones used for sublocalization of the multiple endocrine neoplasia type 1 (MEN1) locus

Summary Multiple endocrine neoplasia type 1 (MEN1) is characterized by neoplasia of the parathyroids, the pancreas, and the pituitary. Tumorigenesis involves unmasking of a recessive mutation at the MEN1 locus, which has been mapped to the centromeric part of chromosomal region 11q. In order to localize the MEN1 gene further and to make its isolation possible, a number of new markers were isolated. Two radiation-reduced somatic cell hybrids were identified that only contained markers close to and flanking the MEN1 region. DNA from these hybrids was used for the construction of a cosmid library, and clones containing human inserts were isolated. In addition, cosmid clones were isolated for locus expansion of 7 other markers that were mapped to the 11q12–13.2 region. The 33 newly isolated clones together with 25 previously published markers from this region were analyzed in a panel of radiation-reduced somatic cell hybrids. From the hybridization pattern, the region was divided into 11 parts. New restriction fragment length polymorphisms were identified in 7 of the newly isolated cosmid clones and in one plasmid. These were then used to sublocalize meiotic cross-overs more precisely in two MEN1 families, thus refining the mapping of the disease gene.     

Seismic signal transmission between burrows of the Cape mole-rat,Georychus capensis

Summary Both seismic and auditory signals were tested for their propagation characteristics in a field study of the Cape mole-rat (Georychus capensis), a subterranean rodent in the family Bathyergidae. This solitary animal is entirely fossorial and apparently communicates with its conspecifics by alternately drumming its hind legs on the burrow floor. Signal production in this species is sexually dimorphic, and mate attraction is likely mediated primarily by seismic signalling between individuals in neighboring burrows. Measurements within, and at various distances away from, natural burrows suggest that seismic signals propagate at least an order of magnitude better than auditory signals. Moreover, using a mechanical thumper which could be triggered from a tape recording of the mole-rat's seismic signals, we established that the vertically-polarized surface wave (Rayleigh wave) propagates with less attenuation than either of the two horizontally-polarized waves. Thus, we tentatively hypothesize that Rayleigh waves subserve intraspecific communication in this species.Abbreviations PPM pulses per min - SB simulated burrow - SD standard deviation - SPL sound pressure level     

Linkage studies of Usher syndrome type 1: exclusion results from the Usher syndrome consortium.

Usher Syndrome Type 1 is an autosomal recessive disease characterized by profound congenital hearing impairement and vestibular dysfunction followed by the onset of retinitis pigmentosa in childhood or early adolescence. Members of the Usher Syndrome Consortium, whose objective is to locate and isolate the genes for Usher syndrome, have pooled linkage data from 36 families with 111 affected individuals. We report the analysis of 206 blood group, protein, and DNA marker polymorphisms. No evidence of linkage heterogeneity among families was found for any of the markers studied; the negative lod scores exclude the locus for this disease from about 39% of the genome. Our results indicate the regions of the genome to which our continuing efforts should be directed.     

Regulation of Phytochrome Message Abundance in Root Caps of Maize : Spatial, Environmental, and Genetic Specificity

In many cultivars of maize (Zea mays L.) red light affects root development via the photomorphogenetic pigment phytochrome. The site of perception for the light is the root cap. In the maize cultivar Merit, we investigated phytochrome-mediated events in the cap. We established that the message encoded by the phyA1 gene was most abundant in dark-grown tissue and was asymmetrically distributed in the root cap, with greatest expression in the cells which make up the central columella core of the cap. Phytochrome message was negatively autoregulated in a specific region within the root cap. This autoregulation was sensitive to very-low-fluence red light, and thus was characterized as a phytochrome-mediated, very-low-fluence event. The kinetics of message reaccumulation in the dark were also examined and compared to the kinetics of the light requirement for root gravitropism in this cultivar. Similarly, the degree of autoregulation present in two other maize cultivars with different light requirements for gravitropic sensitivity was investigated. It appears that the Merit cultivar expresses a condition of hypersensitivity to phytochromemediated light regulation in root tissues. We conclude that phytochrome regulates many activities within the cap, but the degree to which these activities share common phytochrome-mediated steps in not known.     

Patchiness and composition of coral reef demersal zooplankton

Zooplankton samples were collected weekly for a full year withdemersal traps on a coral reef off the west coast of Barbados.There was a marked temporal variability in weekly catches bothin terms of abundance and biomass. Patchiness occurred at allsampling frequencies from 2 to 26 weeks, but spectral analysisindicated a variance shift at a frequency of 8–10 weeksAggregations of the two most abundant taxa, the copepoditesand the microzooplankton, occurred at 8–12 week intervalsand significant differences in abundance and biomass were foundbetween mean bimonthly zooplankton catches Lagged cross-correlationsat 7 and 11 weeks between chlorophyll and microzooplankton andcopepodites suggest that aggregations are connected to cyclesof primary production. There was a negative correlation betweenzooplankton abundance and surface water salinity in 8 of 16taxa Copepods were the most abundant taxon overall. Microzooplanktonand copepodites comprised 96% of the abundance and 66% of thebiomass Decreases in taxonomic richness and in diversity wereassociated with patchiness of small-sized copepodites and microzooplankton,suggesting that composition was altered and stability temporarilylessened during peaks of abundance