A geographical mosaic of coevolution in a slave-making host-parasite system.

Three different isolated populations of the slave-making ant Rossomyrmex minuchae, sympatric with its obligate host Proformica longiseta, are known from the high mountains of southern Spain. To test the prediction that the slave-maker and its host represent a coevolutionary geographical mosaic, we studied the variation in the cuticular hydrocarbons (CHCs) as the trait most likely to show the selection mosaic, plus trait remixing by the gene flow in the populations of each species by means of microsatellites. We found within populations, host and parasite had more similar CHC profiles than between the populations or between parasites and allopatric hosts. The differences between the CHC profiles of the host and parasite, which may be responsible for the level of tolerance towards the parasite, varied between the populations suggesting the existence of a selection mosaic of coevolution. Furthermore, P. longiseta showed higher gene flow than R. minuchae, which would allow local variation in the coevolution of the host and parasite while allowing some trait remixing.

Prucalopride and donepezil act synergistically to reverse scopolamine-induced memory deficit in C57Bl/6j mice.

It is known that 5-HT(4) receptor agonists increase sAPPalpha levels in the cortex and hippocampus of mice as well as in a model of Alzheimer's disease (AD). As sAPPalpha is thought to have pro-mnesic properties, we assessed whether its increase induces cognitive improvement in a spatial memory task and whether it reverses a scopolamine-induced memory deficit. Mice treated or not treated with scopolamine were trained in the Morris water maze for 3 days. Before the probe test, they received an injection of either a 5-HT(4) receptor agonist (prucalopride or RS 67333), or an acetylcholinesterase inhibitor (donepezil), or both drugs. As expected, scopolamine decreased performance, an effect that was not reversed by the drugs tested when injected alone. However, prucalopride (5 mg kg(-1), s.c.) acted synergistically with donepezil (0.75 mg kg(-1), s.c.) to counteract completely scopolamine-induced amnesia. Western blot analysis of tissue homogenates in the cortex and hippocampus shows that sAPPalpha levels did not differ between saline- and scopolamine-treated mice. Furthermore, a region-dependent drug action was observed since the scopolamine-treated mice display a tendency to increase sAPPalpha levels in the hippocampus after donepezil or in the cortex after prucalopride. Our results suggest that a combined treatment with a 5-HT(4) receptor agonist with an acetylcholinesterase inhibitor has beneficial effects on memory in mice. Moreover, it seems to enhance sAPPalpha levels in two brain regions highly affected in AD. Thus, a drug polytherapy could be interesting not only to enhance cognitive performance and decrease drawbacks but also to get the best action in each brain region.

Age- and sex-based nomograms from coronary artery calcium scores as determined by electron beam computed tomography.

We present data for 18,785 patients undergoing electron beam computed tomography, dividing them by sex and age (using 5-year age increments) to determine coronary artery calcium scores representing the 50th and 75th percentiles for each group. Because risk stratification is an integral part of determining therapies for coronary artery disease, age- and sex-based scores may be more clinically useful than total coronary artery calcium scores alone.

The diversity of rearranged immunoglobulin heavy chain variable region genes in peripheral blood B cells of preterm infants is restricted by short third complementarity-determining regions but not by limited gene segment usage.

The immunoglobulin diversity is restricted in fetal liver B cells. This study examined whether peripheral blood B cells of extremely preterm infants show similar restrictions (overrepresentation of some gene segments, short third complementarity-determining regions [CDR3]). DNA of rearranged immunoglobulin heavy chain genes was amplified by polymerase chain reaction, cloned, and sequenced. A total of 417 sequences were analyzed from 6 preterm infants (25-28 weeks of gestation), 6 term infants, and 6 adults. Gene segments from the entire V(H) and D(H) gene locus were rearranged in preterm infants, even though the D(H)7-27 segment was overrepresented (17% of rearrangements) compared to term infants (7%) and adults (2%). CDR3 was shorter in preterm infants (40 +/- 10 nucleotides) than in term infants (44 +/- 12) and adults (48 +/- 14) (P <.001) due to shorter N regions. Somatic mutations were exclusively found in term neonates and adults (mutational frequency 0.8% and 1.8%). We conclude that preterm infants have no limitations in gene segment usage, whereas the diversity of CDR3 is restricted throughout gestation.

Incidental detection of preclinical renal tumors with electron beam computed tomography: report of 26 consecutive operated patients.

PURPOSE: The purpose of this work was to describe the positive predictive value of electron beam CT (EBCT) for diagnosis of solid renal tumors. METHOD: Among 11,932 consecutive patients undergoing screening EBCT, 27 cases met EBCT criteria for solid renal tumors. Twenty-six of 27 patients underwent surgery. RESULTS: Surgical pathology identified 25 solid renal tumors and 1 adrenal hemorrhage with thrombus. Twenty tumors were classified as T1N0M0, one was T2N0M0, and one was T3aN0M0. All tumor patients are clinically well at 1-41 months (mean 17 months) postoperatively. None of the patients had clinical signs or symptoms characteristic of renal malignancy. CONCLUSION: EBCT is an effective tool for detection of solid renal tumors in a healthy outpatient population (positive predictive value 0.96). The detection rate is low [0.2% (26/11,932) at our facility] in patients undergoing EBCT for other indications. The cost-effectiveness and sensitivity of this technique for solid renal tumor detection among various populations remain to be determined.