Serum concentrations of oestradiol-17beta, progesterone, relaxin and chorionic gonadotrophin during blastocyst implantation in natural pregnancy cycle and in embryo transfer cycle in the rhesus monkey

The present study was undertaken to assess the temporal association between the profiles of serum concentrations of oestradiol-17beta, progesterone, chorionic gonadotrophin (CG) and relaxin in pregnancies established naturally, and after embryo transfer, as well as in failed pregnancies in rhesus monkeys. In naturally mated cycles (group 1) a conception rate of 75% was obtained. In group 1, the mean day of CG detection in serum was 11.5 +/- 1.9 day post-ovulation, and for relaxin, 9.0 +/- 2.5 day post-ovulation. In group 2, embryo transfer to synchronous, non-mated surrogate recipients was performed; seven embryo transfer cycles yielded three pregnancies which were allowed to continue to term and normal infants were delivered. In embryo transfer cycles the mean day of CG detection was 14.8 +/- 1.8 day post- ovulation, and for relaxin, 11.4 +/- 2.6 day post-ovulation. A delay of about 3 days was observed in the appearance in circulation of CG (P < 0.05) and also of relaxin (P < 0.05) between natural mated and embryo transfer conception cycles. Significant differences (P < 0.05 for progesterone and P < 0.03 for oestradiol) were obtained for the areas under the curves for progesterone and oestradiol between days 12 and 16 in conception cycles compared with failed pregnancies. These data provide the first observation of the normal hormonal signals associated with maternal recognition of transferred embryos during the peri- implantation period, and suggest that the use of such an experimental primate embryo transfer model may help to elucidate components of maternal and embryonic signal-response mechanisms during embryo implantation.      

Sequence comparison of human and yeast telomeres identifies structurally distinct subtelomeric domains

We have sequenced and compared DNA from the ends of three human chromosomes: 4p, 16p and 22q. In all cases the pro-terminal regions are subdivided by degenerate (TTAGGG)n repeats into distal and proximal sub- domains with entirely different patterns of homology to other chromosome ends. The distal regions contain numerous, short (<2 kb) segments of interrupted homology to many other human telomeric regions. The proximal regions show much longer (approximately 10-40 kb) uninterrupted homology to a few chromosome ends. A comparison of all yeast subtelomeric regions indicates that they too are subdivided by degenerate TTAGGG repeats into distal and proximal sub-domains with similarly different patterns of identity to other non-homologous chromosome ends. Sequence comparisons indicate that the distal and proximal sub-domains do not interact with each other and that they interact quite differently with the corresponding regions on other, non- homologous, chromosomes. These findings suggest that the degenerate TTAGGG repeats identify a previously unrecognized, evolutionarily conserved boundary between remarkably different subtelomeric domains.      

Fast reconstruction of 3D time-of-flight PET data by axial rebinning and transverse mashing

Faster scintillators like LaBr(3) and LSO have sparked renewed interest in PET scanners with time-of-flight (TOF) information. The TOF information adds another dimension to the data set compared to conventional three-dimensional (3D) PET with the size of the projection data being multiplied by the number of TOF bins. Here we show by simulations and analytical reconstruction that angular sampling for two-dimensional (2D) TOF PET can be reduced significantly compared to what is required for conventional 2D PET. Fully 3D TOF PET data, however, have a wide range of oblique and transverse angles. To make use of the smaller necessary angular sampling we reduce the 3D data to a set of 2D histoprojections. This is done by rebinning the 3D data to 2D data and by mashing these 2D data into a limited number of angles. Both methods are based on the most likely point given by the TOF measurement. It is shown that the axial resolution loss associated with rebinning reduces with improved timing resolution and becomes less than 1 mm for a TOF resolution below 300 ps. The amount of angular mashing that can be applied without tangential resolution loss increases with improved TOF resolution. Even quite coarse angular mashing (18 angles out of 324 measured angles for 424 ps) does not significantly reduce image quality in terms of the contrast or noise. The advantages of the proposed methods are threefold. Data storage is reduced to a limited number of 2D histoprojections with TOF information. Compared to listmode format we have the advantage of a predetermined storage space and faster reconstruction. The method does not require the normalization of projections prior to rebinning and can be applied directly to measured listmode data.     

Interaction of platelet plasma membranes with thrombin-activated platelets

This study described the binding of platelet plasma membranes to either control or thrombin-activated platelets. Glycoproteins in plasma membranes isolated from human platelets were labeled by oxidation with periodate followed by reduction with [3H]NaBH4. Labeled membranes were incubated with either control or thrombin-activated platelets. The amount of membranes bound was measured by separating platelets with bound membranes from solution by rapid centrifugation through 27% sucrose and determining the amount of radioactivity associated with platelets. Five- to sevenfold more membranes bound to thrombin- activated platelets than to control platelets. This enhanced binding of labeled membranes was completely inhibited by an excess of unlabeled platelet membranes. Human erythrocyte membranes had little affinity for either washed or thrombin-activated platelets and therefore did not compete for platelet-membrane binding. Binding of platelet membranes to thrombin-treated platelets was inhibited by prior incubation of the platelets with PGI2 suggesting that the enhanced binding of membranes was to activated platelets. This study demonstrates that the purified platelet membranes have functional sites that can mediate membrane binding to platelets and that quantitation of membrane binding appears to reflect the increased aggregation capability of activated platelets.     

A cross-sectional study of fatigue and sleep quality before and after kidney transplantation

Fatigue and sleep disturbances are common problems for adults with chronic kidney disease or end-stage renal disease. However, these issues have not been examined much in the context of kidney transplantation (KTx). This study characterizes these outcomes in the KTx population and examines their association with psychological functioning and quality of life (QOL). A cross-sectional cohort of 100 wait-listed pre-KTx and 100 post-KTx patients at one transplant center in the United States completed validated fatigue, sleep, mood, and QOL questionnaires, and their medical records were reviewed. Pre-KTx patients had higher levels of fatigue frequency, fatigue severity, and fatigue disruptiveness than post-KTx patients. Also, pre-KTx patients had more difficulty with sleep quality, latency, duration, efficiency, and disturbance and were more likely to have "poor" sleep quality compared with post-KTx patients. Multivariate predictors of high fatigue severity for both pre- and post-KTx patients were high body mass index (BMI), poor sleep quality, and mood disturbance, while poor sleep quality was predicted by high BMI and mood disturbance. Most sociodemographic and clinical parameters were not associated with fatigue severity or sleep disturbance. Fatigue and sleep disturbances are common before and after KTx, and study findings have important implications for their assessment and management.     

FM sonography in diffuse liver disease: prospective assessment and blinded analysis

FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease.