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Seminal prostaglandins in men with subnormal sperm motility and therapeutic treatment

The contents of prostaglandins in seminal plasma from a total of 73 men were evaluated. The subjects were grouped as follows: normospermic men, patients with impaired motility, patients with small untreated varicocele and patients with impaired motility and Kallikrein therapy. Sperm density, morphology and motility were examined. High performance reversed phase liquid chromatography (HPLC) in combination with specific radioimmunoassays were used for the determination of PGE2, PGI2 and PGF2 alpha. There was a significant difference (p less than 0.025; F-test) between the PGI2 concentrations in patients with impaired motility (5.6 +/- 1.4 pg/mg protein) and normal men (8.8 +/- 3.7 pg/mg protein). PGE2 and PGF2 alpha were significantly different in patients with varicocele (p less than 0.025, F-test). Wide ranges of prostaglandins occurred in the Kallikrein-group with no significant differences. We conclude that: a) PGI2 is an additional prostaglandin compound in seminal plasma, b) its measurement may not be useful as diagnostic parameter in subfertile men and c) Kallikrein has no influence on the prostaglandin content in seminal plasma and other seminal parameters as motility, motility index and sperm counts.     

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Magnetic and other non-visual orientation mechanisms in some cave and surface urodeles

Animals adapted to light-deprived habitats might have improved non-visual sensory systems. Specimens of several cave-dwelling species of urodeles spontaneously and persistently align to natural or artificially-modified permanent magnetic fields. Video observations under dim infrared illumination revealed an obvious individual preference for one particular magnetic direction in every animal tested. Therefore, animals changed alignments predictably when the horizontal magnetic field vector (compass direction) was artificially reversed or deviated. When the vertical vector was compensated, individuals aligned axially. With the vertical vector reversed (inclination upward), either axial alignment was still typical, or the individuals behaved as with the horizontal vector reversed. However, reactions as to the natural field occurred as well. The findings suggest a receptor mechanism that needs both horizontal and vertical magnetic cues, but it is still an open question how and where the physical and physiological mechanisms of magnetic transduction and reception are realized. The visual system is likely not necessary because Proteus is ontogenetically deprived of eyesight, and the other species were blindfolded due to the faint infrared illumination. The results therefore tend to favor those putative receptor mechanisms, assumed to work by means of magnetite nano-elements. In sum, the ability to align within the geomagnetic field may be considered a prerequisite for magnetic orientation and is, among other sensory improvements, judged to be highly relevant as an important sensorial and ecological adaptation to light-deprived habitats.     

siRNAs containing 2′-fluorinated Northern-methanocarbacyclic (2′-F-NMC) nucleotides: in vitro and in vivo RNAi activity and inability of mitochondrial polymerases to incorporate 2′-F-NMC NTPs

We recently reported the synthesis of 2′-fluorinated Northern-methanocarbacyclic (2′-F-NMC) nucleotides, which are based on a bicyclo[3.1.0]hexane scaffold. Here, we analyzed RNAi-mediated gene silencing activity in cell culture and demonstrated that a single incorporation of 2′-F-NMC within the guide or passenger strand of the tri-N-acetylgalactosamine-conjugated siRNA targeting mouse Ttr was generally well tolerated. Exceptions were incorporation of 2′-F-NMC into the guide strand at positions 1 and 2, which resulted in a loss of the in vitro activity. Activity at position 1 was recovered when the guide strand was modified with a 5′ phosphate, suggesting that the 2′-F-NMC is a poor substrate for 5′ kinases. In mice, the 2′-F-NMC-modified siRNAs had comparable RNAi potencies to the parent siRNA. 2′-F-NMC residues in the guide seed region position 7 and at positions 10, 11 and 12 were well tolerated. Surprisingly, when the 5′-phosphate mimic 5′-(E)-vinylphosphonate was attached to the 2′-F-NMC at the position 1 of the guide strand, activity was considerably reduced. The steric constraints of the bicyclic 2′-F-NMC may impair formation of hydrogen-bonding interactions between the vinylphosphonate and the MID domain of Ago2. Molecular modeling studies explain the position- and conformation-dependent RNAi-mediated gene silencing activity of 2′-F-NMC. Finally, the 5′-triphosphate of 2′-F-NMC is not a substrate for mitochondrial RNA and DNA polymerases, indicating that metabolites should not be toxic.     

Reversed-phase high-performance liquid chromatographic method for the determination of the 11-hydroxythromboxane B2 anomers equilibrium

An improved reversed-phase HPLC method for the separation and detection of both hemiacetalic 11-hydroxy anomers of thromboxane B₂ (TXB₂) is described. Water-acetonitrile mixtures have served as mobile phases. By diminishing stepwise the temperature of the chromatographic system from 40 to 0°C, the UV-absorbance profile of TXB₂ changed from one broad peak to two clearly separated narrow peaks corresponding to the two anomers existing in equilibrium. Modification of the mobile phase pH from 1.6 to 6.9 (0°C) resulted in different concentration ratios of the anomers. The equilibrium constant and the Gibbs free energy were calculated. The intermediate open aldehyde form of TXB₂ is unstable and, therefore, cannot be observed either by HPLC or by ¹H NMR measurements.     

Cell cycle re-entry of quiescent mammalian nuclei following heterokaryon formation

When 3T3 mouse fibroblasts are made quiescent by serum deprivation and are then fused with tsAF8 hamster fibroblasts synchronized by a combination of high temperature block and hydroxyurea, the nuclei of binucleated heterokaryons which are formed enter S phase asynchronously in media containing low levels of serum. The tsAF8 nuclei of these biphasic heterokaryons enter S phase shortly after fusion, as do the tsAFS nuclei of homokaryons in the same culture. In contrast, the nuclei of the biphasic heterokaryons which have been contributed by quiescent 3T3 enter S phase only after a lag following fusion. This suggests that the quiescent nucleus within the heterokaryon is stimulated by factor(s) from the more advanced cell to re-enter the cell cycle in the absence of serum. In contrast to factors which induce the immediate synthesis of DNA, these factors may be those responsible for the transition of a cell from a non-proliferating to a proliferating state.