No time to relax: Age-dependent infectivity of cercariae in marine coastal ecosystems

Age dynamics of the ability of cercariae of two digenean species, Himasthla elongata (Himasthlidae) and Renicola parvicaudatus (Renicolidae), to infect the second intermediate host (SIH), mussels (Mytilus edulis), was investigated experimentally. This is the first study of this kind made on cercariae transmitted in the intertidal of the northern seas. The larvae of all tested ages (from 0.5 to 6 hr) were equally successful in infecting mussels. This finding disagrees with the literature data on cercariae of several freshwater digeneans, which are practically incapable of infecting the SIH during the first 1-3 hr of life. The presence of a time delay before the attainment of the maximum infectivity (TDMI) may be associated with the need for physiological maturation of cercariae in the very beginning of their life in the environment, the need for their broad dispersion, and the prevention of superinfection of the downstream host. The absence of TDMI in the cercariae examined in our study could be associated with the instability of environmental factors in the marine intertidal (wave impact, tidal currents). These factors promote a broad dispersion of cercariae in the intertidal biotope and prevent superinfection of potential SIHs. Biological and behavioural features may also play a role. We hypothesize that the presence or absence of TDMI does not depend on the taxonomic affiliation of the cercariae but is determined by the transmission conditions.

Quality of life in patients with primary hyperparathyroidism before and after parathyroidectomy: long term single center experience

BACKGROUND

Primary hyperparathyroidism (PHPT) is a common endocrine disorder caused by a parathyroid tumor or hyperplasia, which is often accompanied with quality of life (QoL) impairment. A parathyroidectomy (PTX) is the preferred standard treatment for PHPT patients. In this single center study we aimed to evaluate the impact of PHPT on patient's QoL and identify QoL changes at early and long-term follow-up after surgery.

METHODS

All the patients underwent routine PTX with the removal of the suspected hyperparathyroid gland(s). Patients filled out generic QoL questionnaire RAND SF-36, specific questionnaire PHPQoL and specific symptom assessment questionnaire PAS upon admission to the hospital before surgery, at 3 months, 12 months and 24 months after surgery.

RESULTS

A total of 92 patients with PHPT (median age was 56 years, 95.7% females) were included in the study. Before PTX patient's QoL by SF-36 scores was significantly lower as compared to healthy controls (p < 0.01). Almost 40% of patients had poor or very poor QoL. The most frequent symptoms by PAS before surgery were as follows: tiredness (97.8% of patients), weakness (94.6%), forgetfulness (94.6%), mood changes (90%), feeling "blue"/depression (88%), joint pains (83.3%), headaches (80.2%), constant irritability (77.2%), bone pains (75%), thirst (70.7%) and trouble getting out of a chair (67.4%). The half of the patients had moderate-to-severe (≥ 40 scores) tiredness, weakness, joint pains, forgetfulness, as well as mood changes. Post-operative QoL changes were analysed in the group of 72 patients. After surgery there was significant improvement in QoL by all scales of SF-36 questionnaire, excluding bodily pain, and the PHPQoL total score (GEE, p < 0.01) as compared with their values before surgery. Also severity of tiredness, mood changes, weakness and forgetfulness significantly decreased after surgery as compared to their baseline values (GEE, p < 0.05). Decreased mental component of QoL by PHPQoL (OR = 0.927, 95%CI = 0.874-0.984, p = 0.013) predicted improved QoL after surgery.

CONCLUSIONS

Patients with PHPT demonstrated significantly impaired QoL in physical, psychological and social functioning as well experienced a wide profile of common PHPT symptoms. Successful PTX was accompanied with remarkable QoL improvement and decrease in subjective symptoms for at least 24 months after surgery.

Comparative study of topogenesis of cytochrome P450scc (CYP11A1) and its hybrids with adrenodoxin expressed in Escherichia coli cells

Hybrid proteins consisting of the mature form of cytochrome P450scc (mP) and adrenodoxin (Ad), attached to either the NH2- or COOH-terminus (Ad-mP and mP-Ad, respectively), were expressed in E. coli. Spectral and catalytic properties of P450scc were studied using the membrane fraction of E. coli cells. It has been shown that the Ad amino acid sequence attached to the termini of the P450scc-domain neither affects the insertion of a hybrid protein into the cytoplasmic membrane nor influences its heme binding ability. The results suggest that Ad attached to the NH2-terminus does not markedly affect the folding of the P450scc-domain, but cholesterol hydroxylase/lyase activity of the Ad-mP hybrid was found to be much lower than that of the native P450scc enzyme. The modification of the COOH-terminus does not alter the specific P450scc activity, but results in a dramatic increase in the amount of hybrid protein with incorrectly folded P450scc domain.

Expression of cytochrome P450scc in Escherichia coli cells: intracellular location and interaction with bacterial redox proteins

Escherichia coli cells producing the mature form of adrenal cytochrome P450scc were used as a model for study of cytochrome P450scc topogenesis. By disruption of transformed E. coli cells and centrifugation of the homogenate under conventional conditions, we obtained membrane and soluble (high-speed supernatant) fractions both containing the recombinant protein. Gel-permeation high performance liquid chromatography showed that in the high-speed supernatant the native cytochrome P450scc exists exclusively as a component of membrane fragments exceeding 400 kD. These data supported by kinetic assays suggest that the >400-kD particles containing P450scc are lipoprotein associates. In total, we failed to detect a genuine soluble cytochrome P450scc in the E. coli cells, which suggests that membrane insertion is an obligatory stage of holoenzyme formation. In the high-speed supernatant supplemented with NADPH, cytochrome P450scc underwent one-electron reduction and could convert 22R-hydroxycholesterol into pregnenolone. Thus, we have for the first time observed functional coupling of cytochrome P450scc with the bacterial electron transfer system.

[The role of stress-echocardiography in diagnostics of hemodynamically significant coronary artery stenosis and determination of indications for myocardial revascularisation.]

In 118 patients dobutamine (n=108) or exercise (n=10) stress-echocardiography and coronary angiography were carried out within time interval of 4 weeks. Retrospective analysis of data obtained showed that sensitivity and specificity of stress echocardiography for detection of more than 70% coronary artery stenosis was 75 and 71%, respectively. No significant reduction of sensitivity or specificity was found in any clinical group. Negative result of stress echo in most of the cases evidenced for continuation of conservative therapy while positive result in 66% of cases attested necessity of myocardial revascularization. Detection of stress induced disturbances of local myocardial contractility could be used as a proof of hemodynamic significance of 50-70% coronary artery stenosis.