Effects of structural variations on the hydrogen bond pairing between adenine derivatives and thymine

<p><strong>Abstract:</strong><strong> </strong>The hydrogen bonding between substituted adenines and thymine was investigated by density functional theory computations at the B3LYP/6-311+G(2d,2p) level. The effect of 20 different polar substituents at position 8 in adenine was examined in detail. Three different theoretical parameters, reflecting the electrostatics at the atoms involved in hydrogen bonding, were applied. An excellent correlation between electrostatic potentials at the bonding atoms in the monomer adenines and interaction energies was derived (Eqn. 2). It can be employed in designing bioactive adenine derivatives that are able to bind with a finely adjusted strength to thymine bioreceptor sites. NBO and Hirshfeld atomic charges are found to be less successful as reactivity predictors in these interactions.</p>

Numerical chromosome disorders in the common marmoset (Callithrix jacchus)--comparison between two captive colonies

BACKGROUND

Chromosomal analyses were performed for marmosets from two colonies - Deutsches Primatenzentrum (DPZ) and Biomedical Primate Research Centre (BPRC). Chlorine-based disinfectants are used in DPZ; no chemical disinfection is applied in BPRC.

METHODS

The rates of chromosomal non-disjunction, polyploidy and endoreduplication were investigated after G-banding.

RESULTS

For DPZ monkeys, the mean rates of non-disjunction were 7.6% for bone marrow and 11.3% for lymphocytes. The polyploidy level was 2.5% in bone marrow and 0.8% in blood. Frequency of endoreduplication in bone marrow and in leucocytes was 0.5% and 0.8%, respectively. For BPRC, the rate of non-disjunction in leucocytes (1.3%) was significantly lower than that for DPZ; the polyploidy rate (0.2%) in blood was lower than that in DPZ; endoreduplication was not observed.

CONCLUSION

The levels of chromosomal disorders are elevated for DPZ colony. We suggest that the increased rate of chromosomal disorders in DPZ marmosets can be related to the chemical disinfection of their environment.

[Investigation of cytokeratin and vimentin intermediate filaments in polycystic ovaries (PCOS) -- presence and specific structure of Balbiani body in primordial follicles]

Despite of the importance of cytoskeletal proteins for ovarian function and pathology, very few studies have addressed the presence and distribution of these proteins in polycystic ovaries. We investigated sections of human polycystic ovarian tissue for vimentin and a set of cytokeratins by epifluorescence. The studied proteins showed strong colocalization. Positive reaction was detected in two main ovarian compartments: with weak intensity in follicular cells and very strong in perinuclear position in oocytes of primordial follicles. Epifluorescent study of the oocytes from primordial follicles allowed us to identify the immunopositive structure in oocytes as Balbiani body, a transient organelle responsible for establishing oocyte polarity and ooplasm gradients in nonmammalian vertebrates. Our results suggest functional interaction of different types of cytoplasmic intermediate filament proteins in polycystic ovaries and a possible importance of the Balbiani body for human oogenesis in norm and pathology.

Improvement of seminal parameters with Prelox: a randomized, double-blind, placebo-controlled, cross-over trial

In a randomly allocated, double-blind, placebo-controlled, cross-over design, 50 infertile patients were treated for 1 month with placebo or a combination of l-arginine aspartate and Pycnogenol (Prelox). Semen samples were examined at 4 week intervals according to WHO criteria. Treatment with Prelox increased significantly the semen volume, concentration of spermatozoa, percentage of motile spermatozoa and percentage of spermatozoa with normal morphology compared with placebo. The placebo had no influence on the parameters of seminological analysis. Intake of Pycnogenol for 1 month improved the fertility index to normal values. After treatment, the fertility index decreased again to infertile status. No unwanted effects were reported. Prelox seems to be a promising alternative to treat patients with mild infertility.

Improvement of erectile function with Prelox: a randomized, double-blind, placebo-controlled, crossover trial

In a randomly allocated, double-blind, placebo-controlled, crossover design, 50 patients with mild to moderate erectile dysfunction (ED) were treated for 1 month with placebo or a combination of L-arginine aspartate and Pycnogenol (Prelox). Patients reported sexual function from diaries. Testosterone levels and endothelial NO synthase (e-NOS) were monitored along with routine clinical chemistry. Intake of Pycnogenol for 1 month restored erectile function to normal. Intercourse frequency doubled. e-NOS in spermatozoa and testosterone levels in blood increased significantly. Cholesterol levels and blood pressure were lowered. No unwanted effects were reported. Prelox is a promising alternative to treat mild to moderate ED.

[Sperm parameters in male idiopathic infertility after treatment with prelox]

The diagnosis of male infertility is determinate after assessment of sperm quality and clinical study. In nearly 30% of the cases nevertheless detailed clinical and laboratory study it can't be discovered the cause and on the bases of exclusion criteria set the diagnosis idiopathic infertility. The object of our study was investigation of the group patients (n=50) with idiopathic infertility treated with Prelox and to be studied its effects on spermatozoa parameters.

MATERIAL AND METHODS

The study design was double-blind, placebo-controlled, cross-over, randomized study, including introduction period (1 month), two therapeutic periods (each one of 1 month) separated with 1 month wash out period and concluding period of 1 month. There was applied a new method for treatment with mechanism of action stimulation the production cGMP of spermatozoa endothelial nitric oxide synthase (eNOS). This is not surprising achieving results show improvement of sperm quality. The methods of the study were: 1. Assessment of the conventional semen analysis (according the criteria of WHO, 1999). 2. Spermatozoa function tests. 3. Spermatozoa-cervical mucus penetration tests.

RESULTS

The obtained results showed improvement of sperm quality, in the middle-aged men the therapeutic answers was better than in younger. In conclusion the therapy with Prelox improve sperm parameters in men with idiopathic infertility. Pycnogenol (one of the constituents of Prelox) has powerful antioxidative influence ameliorating spermatozoa function.

New real-time analytical applications of electrochemical quartz crystal microbalance Stoichiometry and phase composition monitoring of electrodeposited thin chalcogenide films

The electrochemical quartz crystal microbalance (EQCM) has recently gained increasing popularity as a powerful tool for electrochemical interface examinations. This paper reports on its great potential for developing new real-time analytical protocols. Potentiostatic coulometry is used in conjunction with quartz crystal microgravimetry (QCMg) with controlled hydrodynamics to develop two new analytical procedures: real-time stoichiometry monitoring of electrodeposited binary chalcogenide films and phase composition quantification of electrodeposited ternary chalcogenide compounds. The newly developed EQCM methods are illustrated on the examples of Ag2+deltaSe-electrodeposited films and the electroformation of ternary CuAgSe-films. Both compounds have been successfully used as ion-selective membranes for flow-injection detectors. The experimental set-up including hydrodynamic control, the main strategy of the approach used and its scope and limitations are broadly discussed. The obtained data allow for real time profile monitoring of either stoichiometry (Ag2+deltaSe-case) or phase composition (CuAgSe-case).

[Assessment of sperm quality as a male factor in couple's infertility]

The purpose of the present review is to present laboratory assessment of some studies of human seminal fluid and spermatozoa - cervical-mucus interactions according the last (the fourth edition) of WHO guideline, 1999. There are discussed additional tests for spermatozoa function in connection with male factor in couple's infertility. It is outlined the signification of calculation of some spermatozoa indices for clinical practice. The assessment built on the entire population spermatozoa defines the fertility ability of the small portion spermatozoa reaching the oocyte and leading to fertilization.

[Selecting function of female genital tract in relation with spermatozoa interaction]

The present study includes 50 infertile couples followed sperm parameters: morphology and others indices for ability of penetration in ovulatory cervical mucus during 12 months. It is discussed the possibility of which spermatozoa can participate in the fertilization and the impotence and place of the female genital tract for the selection of morphologically abnormal spermatozoa before reaching the place of fertilization.