Minimal progesterone support required for the maintenance of pregnancy in mice

A study of the degree of progesterone support required for the maintenance of various stages of pregnancy was undertaken in mice. Mated females were ovariectomized at various stages of pregnancy and progesterone and oestradiol support provided by s.c. Silastic implants with known release characteristics. In the earliest stages of pregnancy (days 1-5), very low concentrations of progesterone (<25% of normal physiological values) were sufficient to maintain pre-implantation stages and allow implantation. In the immediate post-implantation period (days 5-9), the development of implantation sites and decidualization required considerably higher progesterone support. In mid-pregnancy (days 11-14), progesterone alone could not maintain pregnancy unless present in very high amounts; however, the presence of oestradiol during this period lowered the progesterone requirements to well within the physiological range. This effect of oestradiol started on day 11 but required the level of oestradiol support to be kept within strictly defined limits, with high concentrations inducing abortion. Progesterone alone was able to maintain pregnancy from day 15. These results indicate that the minimal progesterone support required for pregnancy in mice varies considerably at different stages of pregnancy and is at least partly modulated by oestradiol.      

Evaluation of a non-radioactive DNA probe for confirmatory identification of Neisseria gonorrhoeae

A biotinylated DNA probe combined with a streptavidin-peroxidase complex for the identification of culture isolates of N. gonorrhoeae (Ortho diagnostic systems, Neckargemünd, FRG) was compared with the conventional carbohydrate utilisation test as reference. All 118 strains identified by the reference method as N. gonorrhoeae also gave positive reactions with the DNA hybridisation assay. However, with this test 2 of 23 non-gonococcal Neisseria or Branhamella species were identified as N. gonorrhoeae as well. The study shows that the DNA hybridisation technique can principally be used for the confirmatory identification of N. gonorrhoeae, but since specificity is particularly essential for confirmatory identification, the DNA hybridisation assay evaluated cannot be recommended for routine diagnosis.     

Elastin point mutations cause an obstructive vascular disease, supravalvular aortic stenosis

Supravalvular aortic stenosis (SVAS) is an inherited obstructive vascular disease that affects the aorta, carotid, coronary and pulmonary arteries. Previous molecular genetic data have led to the hypothesis that SVAS results from mutations in the elastin gene, ELN. In these studies, the disease phenotype was linked to gross DNA rearrangements (35 and 85 kb deletions and a translocation) in three SVAS families. However, gross rearrangements of ELN have not been identified in most cases of autosomal dominant SVAS. To define the spectrum of ELN mutations responsible for this disorder, we refined the genomic structure of human ELN and used this information in mutational analyses. ELN point mutations co-segregate with the disease in four familial cases and are associated with SVAS in three sporadic cases. Two of the mutations are nonsense, one is a single base pair deletion and four are splice site mutations. In one sporadic case, the mutation arose de novo. These data demonstrate that point mutations of ELN cause autosomal dominant SVAS.      

Contextual modulation of synchronization to random dots in the cat visual cortex

Synchronization of neuronal activity has been proposed as a binding mechanism for integration of image properties into one coherent percept. In the present study, we investigated the contextual modulation of synchronization to random dot patterns. Coherent motion of random dots evoked well synchronized responses in area 17 of anaesthetized cats when the stimulus was presented in the compound receptive field of recorded sites. Gradually changing the directional coherence of random dots in the surround while maintaining fully coherent motion of the stimulus in the receptive field significantly suppressed synchronization of neuronal activity for some stimulus conditions. However, usually one or two peaks of increased synchronization were found in the surround coherence tuning curves with low (8–12%) and/or moderate (25–50%) coherence in the surround. At the population level, synchronization was significantly depressed with incoherent motion in the receptive field and when both the surround and the receptive field were jointly stimulated with 0% coherence. The intriguing finding was the discovery of two distinct groups of cells with opposite synchronization changes dependent on the presence or absence of significant synchronization in their spontaneous activity. The latter group of neurons showed peaks of increased synchronization with lower surround coherence, thus probably being more sensitive to the direction of the surround motion. Overall, our findings support the notion that binding of stimulus properties can be achieved by synchronized activity of cortical cells. However, our findings go further than the original hypothesis of feature binding by synchrony to show that synchronization of cortical activity may be directly related to the decision making processes, which in turn are related to the threshold of perception of coherent motion.     

Anxiety during pregnancy and fetal attachment after in-vitro fertilization conception

The aim of this study was to compare 70 couples who had conceived by in- vitro fertilization (IVF) with 63 matched controls for the prevalence of anxiety and quality of attachment to the baby during pregnancy. Results for mothers showed no group differences using a global measure of anxiety, the Spielberger State-Trait Anxiety Inventory. However, pregnancy-specific measures revealed significantly higher levels of anxiety in IVF mothers about the survival and normality of their unborn babies, about damage to their babies during childbirth and about separating from their babies after birth. When IVF mothers were differentiated according to the number of treatment cycles, more differences in anxiety level were revealed, with most increases occurring in mothers who had experienced two or more treatment cycles. IVF fathers did not differ from controls on the global anxiety measure. No data on pregnancy-specific anxiety were available for fathers. Neither IVF mothers nor IVF fathers differed from controls on measures of attachment to the baby during pregnancy. Results are discussed in the context of the need for researchers to employ differentiated and issue-specific measures to identify concerns that may be unique to IVF couples. Clinical implications regarding the need for psychological support during pregnancy are also discussed.      

Oxygenation and lung morphology in a rabbit pediatric ARDS- model under high peak pressure ventilation plus nitric oxide and surfactant compared with veno-venous ECMO

The aim of the study is to investigate which of two treatment options of saline lavage induced ARDS in rabbits is better in terms of oxygenation and prevention of barotrauma: combined high peak pressure ventilation with surfactant administration and inhaled nitric oxide or veno-venous ECMO combined with low peak inspiratory pressure ventilation. MATERIALS AND METHODS: After saline lavage (10 cc/kg repeated as long as foamy retrieval was observed) two combined therapeutic strategies were examined: ventilation with high inspiratory pressures (35 cm H2O) with additional exogenous surfactant administration (100 mg/kg) and inhaled nitric oxide (10 PPM) (n=5, group 1) and low inspiratory pressure (20 cm H2O) ventilation under veno-venous ECMO support (n=5, group 2). The FiO2 was maintained at 1.0 in both groups. The paO2/FiO2 ratio was calculated in 30 minute intervals for 4 hours. After that the animals were sacrificed and the lungs examined macro- and microscopically. Aeration was described in a semiquantitative method using the alveolar expansion index. Oxygenation in group 1 was significantly better than in group 2, it increased significantly after surfactant but not after additional nitric oxide administration. However, the lungs in group 1 showed severe signs of baro/ergotrauma (Hyaline membranes, air leaks, infiltration of polymorphonuclear (PMN) granulocytes and macrophages, break down of alveolar capillary membranes) after 4 hrs of combined therapy, whereas the lungs in group 2 appeared normal. Adding surfactant and NO to a high tidal volume ventilation improved oxygenation, but did not prevent baro/ergotrauma. Ventilation with low inspiratory pressures combined with ECMO caused little baro/ergotrauma but adequate oxygenation could not be achieved, probably due to anatomical features of the rabbit which do not allow appropriate blood flow within the ECMO-circuit.     

Running training and co-ordination between breathing and running rhythms during aerobic and anaerobic conditions in humans

The study was carried out on ten triathletes, six sprinters and ten subjects not trained in running (controls) to assess the effects of training history on the co-ordination between breathing and running rhythms during running on a treadmill. Three exercise intensities were used: 50%, 80% and 110% of the subject's anaerobic threshold (AT). All three intensities were performed twice: once with spontaneous breathing and once with breathing intentionally co-ordinated to the running rhythm. Heart rate, respiratory parameters and leg movements were continuously recorded. Blood lactate concentrations were measured discontinuously. The degree of co-ordination between running and breathing was quantified as the percentage of inspirations and/or expirations starting during the same phase of step. The results showed that the degree of both spontaneous and intended co-ordination at aerobic exercise intensities was in all three groups the same and increased in all groups with increasing intensity from 50% to 80% of AT; further increase of intensity to 110% of AT was associated with a significant decrease of co-ordination in controls and sprinters, whereas triathletes were able to maintain the same high degree of co-ordination as at 80% of AT. It was concluded that running training of either type at aerobic work loads had no effect on the co-ordination between running and breathing rhythms. At anaerobic intensities, however, the degree of co-ordination between running and breathing rhythms was higher in the endurance trained athletes than in the sprinters or in the untrained subjects. The degree of co-ordination increased with increasing regularity of breathing. The ability to increase intentionally the degree of co-ordination by paced breathing was independent of running training and was lowest at anaerobic exercise intensities.