Genomics of steroid hormones: in silico analysis of nucleotide sequence variants (polymorphisms) of the enzymes involved in the biosynthesis and metabolism of steroid hormones

Alterations of steroid hormone biosynthesis and metabolism are suspected to be involved in the pathogenesis of several diseases. Several polymorphisms of the enzymes involved in these processes have already been described and some could be associated with certain diseases. We attempted to examine the sequence variants of these genes in order to find novel variants by an in silico analysis. We analyzed the known human nucleotide sequences of the enzymes p450 side-chain cleavage enzyme, steroid 17-alpha-hydroxylase/17,20-lyase, 3-beta-hydroxysteroid dehydrogenase types 1 and 2, 21-hydroxylase, 11-beta-hydroxylase, aldosterone synthase, aromatase, 11-beta-hydroxysteroid dehydrogenase types 1 and 2, steroid 5-alpha-reductase types 1 and 2, steroid 5-beta-reductase, dehydroepiandrosterone sulfotransferase, 17-beta-hydroxysteroid dehydrogenase types 1–3. The analysis was performed using the National Center for Biotechnology Information Database by the search tool blastn. We found numerous sequence variants in both coding and non-coding sequences. The majority of these sequence variants have already been described, nevertheless, some appear as novel variants. Some of these may also have functional significance. We hypothesize over the possible significance of these findings and briefly review the available literature.     

Application of capillary zone electrophoresis to the analysis and to a stability study of cephalosporins

1-Methylpropyl-2-imidazolyl disulfide (MID) is a novel antitumor agent currently in Phase I clinical trials. The chromatographic behavior of MID and its potential impurity, degradation product, and metabolite 2-mercaptoimidazole (2MI) was studied under reversed-phase (RP) and normal-phase (NP) conditions. Both RP- and NP-HPLC separation methods were developed. RP-HPLC was validated as a stability-indicating assay for MID. NP-HPLC retained both MID and 2MI and pending further validation, could prove useful in the study of MID pharmacokinetics.     

A comparative electromyographical investigation of muscle utilization patterns using various hand positions during the lat pull-down

This study aimed at investigating the effects of different hand positions on the electromyographic (EMG) activity of shoulder muscles during the performance of the lat pull-down exercise. Ten healthy men performed 3 repetitions of the lat pull-down exercise using their experimentally determined 10RM (repetition maximum) weight. Four different common variations of the lat pull-down were used: close grip (CG), supinated grip (SG), wide grip anterior (WGA), and wide grip posterior (WGP). Normalized root mean square of the EMG (NrmsEMG) activity for the right posterior deltoid (PD), latissimus dorsi (LD), pectoralis major (PM), teres major (TM), and long head of the triceps (TLH) were recorded using surface electrodes and normalized using maximum voluntary contractions. Repeated measures analysis of variance for each muscle detected statistical differences (p < 0.05) in myoelectric activity among hand positions during both the concentric and eccentric phases of the exercise. During the concentric phase, NrmsEMG results for the LD included WGA > WGP, SG, CG. For the TLH: WGA > WGP, SG, CG and WGP > CG, SG. For the PD: CG, WGA, SG > WGP. For the PM: CG, WGA, SG > WGP. During the eccentric phase, the LD produced the following patterns: WGA > WGP, SG, CG and WGP > CG. The TLH pattern showed WGA > SG and CG. For the PD: CG > WGA, WGP. The results indicate that changes in handgrip position affect the activities of specific muscles during the lat pull-down movement. Also, performance of the lat pull-down exercise using the WGA hand position produces greater muscle activity in the LD than any other hand position during both the concentric or eccentric phases of the movement.     

Significant differences in capillary electrophoretic patterns of follicular fluids and sera from women pre-treated for in vitro fertilization

Human ovarian follicular fluids and sera obtained from women pre-treated for in vitro fertilization (IVF) were investigated by capillary zone electrophoresis. Comparison of the matching physiological liquids showed substantial differences in the electrophoretic patterns. Significant decrease in the alpha(1)- and gamma-fractions of follicular fluids of every woman were observed, whereas other fractions of the samples did not show such alterations. Since follicular fluid is a product of both, secretion by granulosa cells and diffusion from the theca capillaries, we can assume that the forced production of follicular fluid upon hormone stimulation (with gonadotropin releasing hormone (GnRH), follicle stimulating hormone (FSH) and corionic gonadotroph hormone (hCG)) may play role in the uneven presence of the proteins.     

Regulation of mitochondrial contact sites in neonatal,juvenile and diabetic hearts

Mitochondrial contact sites (MiCS) are dynamic structures involved in high capacity transport of energy from mitochondria into the cytosole. Previous studies revealed that in normal conditions the actual number of MiCS is in correlation with the energy requirements of the heart, particularly with those for its contractile work. Although the detailed mechanisms of signalling between the processes of energy utilisation and MiCS formation in the heart are not yet elucidated, it is known that intracellular Ca²⁺ transients are intimately involved in this crosstalk. The present study is devoted to investigation of Ca²⁺-linked MiCS formation in healthy adult hearts and in hearts with modified Ca²⁺-handling such as in developing, in juvenile and diabetic myocardium. Experiments were performed on hearts of healthy rats on the 22nd embryonal day, 1st, 4th, 7th and 14th postnatal days as well as on adult hearts. Diabetic hearts were investigated on the 8th day after streptozotocin injection (45 mg.kg^–1 i.v.) to adult rats. Intracellular Ca²⁺ movements were affected by modulation of Ca²⁺ concentration in perfusion solution (1.6 or 2.2 mmol.l^–1) in isolated, Langendorff-perfused hearts, by calcium paradox (CaP) or by replacing of Ca²⁺ by Cd²⁺ ions. Elevation of extracellular Ca²⁺ was reflected by 30.1, 10.4 and 24.1% increase in intracellular free Ca²⁺ concentration in healthy adult, diabetic and 14-day old hearts respectively. In developing hearts the amount of MiCS was culminating on the 4th postnatal day. In adult hearts, elevated calcium in the perfusion solution, CaP as well as diabetes led to a significant increase in the amounts of MiCS formed (58.1, 77.2 and 86.5% respectively; p < 0.05). Diabetic and 14-day old hearts naturally exhibited amounts of MiCS comparable to those obtained by Ca²⁺-stimulation of MiCS formation in adult healthy hearts. In contrast to healthy controls, perfusion of diabetic and 14-day old hearts with elevated Ca²⁺ as well as induction of CaP exerted little influence on MiCS formation (4.4 and 8.2% for elevated Ca²⁺; 2.9 and 10.7% for CaP; p > 0.05). A replacement of Ca²⁺ by Cd²⁺ ions lowered the amount of MiCS in healthy adult and diabetic hearts (61 and 52.2%; p < 0.05). In conclusion, during development, the formation of MiCS may be influenced by both, permanent stimulation by Ca²⁺-signalling and the availability of mCPK. In healthy adult hearts the amount of MiCS is modulated by intracellular Ca²⁺ transients in response to changes in extracellular Ca²⁺ concentration. In diabetic hearts the modulation of MiCS formation is naturally attenuated, apparently as a consequence of persisting alterations in Ca²⁺-handling.     

Congenital adrenal hyperplasia: lessons from a multinational study

A study group of paediatric endocrinologists was established in Austria, Czech Republic, Hungary, Slovenia and Slovakia in order to investigate various aspects in children with congenital adrenal hyperplasia (CAH). Five hundred and ninety-eight patients with CAH who were diagnosed between 1969 and 1998 were included in order to analyze the following questions. Epidemiological data: There were significantly fewer males (43%) than females (57%), and the percentage of males did not increase during the observation period. Salt wasters (SW) totalled 64.7%, whereas 35.3% had simple virilizing (SV) CAH. Diagnosis was established significantly later in boys than in girls (median of 26 vs. 13 days for SW, p < 0.0001; 1,817 vs. 1,010 days for SV, p < 0.03). Mortality in the general population was significantly lower than in CAH siblings (1.8% vs. 7.0%, p < 0.0001) or in SW children (2.2% vs. 11.3%, p < 0.0001). According to our calculation with the present clinical diagnostic criteria in Central Europe, from 40 expected CAH patients/year, 2-2.5 SW, and one female and four male SV patients will not be diagnosed. Auxological data: Growth data from 341 patients were analyzed retrospectively. Percentiles were constructed in a longitudinal/cross-sectional study and pubertal growth was described in a longitudinal analysis. Growth of SW patients was impaired in early childhood (0-3 years), but followed a normal course until puberty. In contrast, SV children had a normal growth pattern during early childhood, but were above the standard thereafter. The pubertal growth spurt was of normal magnitude in boys and girls, but started too early. Final height was reduced compared with both standard and target heights. There was no correlation between final height and age of starting treatment or the year of birth. Bone age was accelerated in both CAH types, but more so in SV patients. Molecular genetics: Three hundred and fifty-six patients were investigated for 11-14 of the most frequent mutations by direct allele-specific polymerase chain reaction (PCR) and/or PCR followed by sequence-specific oligonucleotide, single strand chain polymorphism and restriction fragment length polymorphism. In the group as a whole, we most frequently found the Intron 2 splice mutation (30.8%) or a deletion/conversion (28.5%). The Intron 2 mutation was most frequent in the Hungarian population, whereas deletions/conversions were found more frequently in Slovenians. The other mutations had a similar distribution to those seen in other populations. Genotype-phenotype correlation confirms previous reports.     

To thermoconform or thermoregulate? An assessment of thermoregulation opportunities for the lizard<Emphasis Type="Italic"> Zootoca vivipara</Emphasis> in the subarctic

The general model of thermoregulation of ectotherms predicts that thermally challenging environments select for evolution of thermoconformity. Studies of reptilian thermoregulation at climatic extremes are rare and, in the subarctic zone, completely lacking. Thermal characteristics of the habitat of the lizard Zootoca vivipara were studied in the subarctic zone, at the northern margin of its distribution, where lizard density was already extremely low. We found that, during the activity period, the preferred body temperatures of Z. vivipara were not available for a thermoconformer, but available for 7 h for a thermoregulator in an average day. Therefore, thermoconformity is unbeneficial and accurate thermoregulation should be the appropriate strategy. We hypothesise that the extremely low lizard abundance at our subarctic study site is caused by the short activity season and the large daily temperature fluctuations, with night temperatures occasionally falling below zero even during the activity period.