Peptidyl-CCA deacylation on the ribosome promoted by induced fit and the O3'-hydroxyl group of A76 of the unacylated A-site tRNA

The last step in ribosome-catalyzed protein synthesis is the hydrolytic release of the newly formed polypeptide from the P-site bound tRNA. Hydrolysis of the ester link of the peptidyl-tRNA is stimulated normally by the binding of release factors (RFs). However, an unacylated tRNA or just CCA binding to the ribosomal A site can also stimulate deacylation under some nonphysiological conditions. Although the sequence of events is well described by biochemical studies, the structural basis of the mechanism underlying this process is not well understood. Two new structures of the large ribosomal subunit of Haloarcula marismortui complexed with a peptidyl-tRNA analog in the P site and two oligonucleotide mimics of unacylated tRNA, CCA and CA, in the A site show that the binding of either CA or CCA induces a very similar conformational change in the peptidyl-transferase center as induced by aminoacyl-CCA. However, only CCA positions a water molecule appropriately to attack the carbonyl carbon of the peptidyl-tRNA and stabilizes the proper orientation of the ester link for hydrolysis. We, thus, conclude that both the ability of the O3′-hydroxyl group of the A-site A76 to position the water and the A-site CCA induced conformational change of the PTC are critical for the catalysis of the deacylation of the peptidyl-tRNA by CCA, and perhaps, an analogous mechanism is used by RFs.     

Influence of the incoming solar radiation on the bone mineral density in the female adult population in Croatia

The relationship between the bone mineral density (BMD) in Croatian female adults and the average incoming solar radiation at the ground was investigated. The study included 387 volunteers of average age of 60 years from three different towns: Pula (n = 128, age from 35 to 76), Krapina (n = 141, age from 43 to 77), and Zagreb (n = 118, age from 32 to 79). Apart from the different lifestyle, each of above towns is characterized by different incoming solar radiation, where values of 503.3 kJ cm-2, 471.2 kJ cm-2 and 436.3 kJ cm-2 correspond to average annual radiation at the ground for Pula, Krapina and Zagreb, respectively. Heel BMD was measured by clinical bone sonometer (Sahara). On the average the BMD was highest for Pula (0.469 g cm-2) and the lowest for Zagreb (0.433 g cm-2). Similarly, the percentage of normal bones was the highest for Pula (46.1%) and the lowest for Zagreb (32.2%). Osteopenic bones were the most frequent for Zagreb (61.0%), while corresponding figures for Pula and Krapina were 46.9% and 43.6%, respectively. Osteoporosis varied from 6.8% in Zagreb to 11.4% in Krapina. A test of independence by contingency table confirmed at the significance level alpha = 0.05 that probability of normal bone occurrence increases with the increase of incoming solar radiation. Results of the multiple regression analysis suggest the dependence of BMD on woman's age and weight, and incoming solar radiation at the place of habitation.     

Efficacy and safety of propofol sedation during urgent upper gastrointestinal endoscopy--a prospective study

The aim of this study was to investigate both the efficacy and safety of sedation with propofol during urgent therapeutic gastroscopy in patients with upper gastrointestinal bleeding. This prospective study included a total of 110 patients. Propofol was administered intravenously at the starting dose of 1 mg/kg body weight and was followed by repeated doses. Oxygen saturation and heart rate were monitored by pulse oxymetry. The mean dose of propofol administered was 161 +/- 49 mg. Urgent upper GI endoscopy under propofol sedation was successful in 98% of cases. Endoscopists rated the sedation as good in 83.6%, satisfactory in 14.5%, and poor in 1.8% of patients. Potentially harmful drop in oxygen saturation below 85% was observed in 5.5% of patients, whereas a temporary drop in heart rate below 50 beats/min was observed in 11.8%, not requiring any intervention. Almost 93% of patients could not remember the beginning or the end of the intervention. This data demonstrates that sedation with propofol is suitable for use in patients with upper gastrointestinal bleeding undergoing urgent endoscopy.     

Cystitis cystica and recurrent urinary tract infections in children

The pathogenesis of recurrent urinary tract infections (UTIs) in preschool children with anatomically correct urinary tract (UT) is rather obscure. In girls, the bladder wall changes of cystitis cystica (CC) may be per se responsible for UTIs recurrence. During the 20-year period, 127 preschool children (125 girls; median age: 6.1 years) with CC, in whom UT anomalies were excluded, were diagnosed. The mean duration of UTIs symptoms prior to diagnosis was 3.31 +/- 2.51 years. Cystoscopical findings were labelled as mild, moderate and severe in 22.8%, 39.4% and 37.8% of patients, respectively. Following the confirmation of CC, long-term chemoprophylaxis with sulfamethoxazole-trimethoprim/nitrofurantoin was administered. A one year UTI-free period after chemoprophylaxis discontinuation was defined as therapeutic success. With 2.5 years median duration of regular chemoprophylaxis this goal was achieved in 58 children mainly with mild/ moderate CC. Thirty children from "improved/unchanged" group taking regular prophylaxis had significant reduction of UTIs ("improved"). Only 12 children belonging to the same group taking regular prophylaxis and all children with irregular prophylaxis had approximately the same number of UTIs as before treatment ("unchanged"). The "improved/unchanged" outcomes were predominantly found in children with severe form of CC. Although urodynamic disturbances detected in more than 50% of patients in whom urodynamics was performed were not found influential on the disease outcome, they could be responsible for its development. The results of our study suggest that regular and long-lasting chemoprophylaxis remains a basis for successful treatment for majority of patients with CC, even those with severe forms. If not treated properly with chemoprophylactic agents and without fair compliance in taking drugs, the disease is prone to recurrent UTIs.     

Vertebroplasty--high viscosity cement versus low viscosity cement

The patients with intensive pain caused by the vertebra body fracture were treated by application of low viscosity cement (LVC), (Vertebroplastic, DePuy) and high viscosity cement (HVC), (Confidence, DePuy,) into the body, by means of diascopy through unilateral transpendicular approach. Application of LVC was made in 75 patients, on 109 vertebrae, and HVC was applied in 12 patients on 14 vertebrae. Application of LVC was performed on 48 thoracic and 61 lumbar vertebrae and 5 thoracic and 9 lumbar vertebrae were stabilized with HVC. 43 patients were treated for malignancy and in 38 for osteoporosis. For LVC, preoperative VAS score was 8.32 and 2.23 (p < 0.00001) 24 hours after surgery, and it remained stable 3 month later. For HVC, preoperative VAS score was 7.99 and it was 2.5 (p < 0.00001) 24 hours after surgery and 3 months later. In the group of patients treated with LVC, there was 1 serious complication, a paraparesis caused by the leakage of cement into the spinal canal, which was partially recovered after decompression and rehabilitation treatment and 2 superificial infections with S. epidermidis which were cured by means of antibiotics. In 32 vertebrae (32) cement leakage extra ossal, either into vein plexus or intradiscal during surgery were noticed. When HVC was applied, intradiscal leakage occurred in one case only (8%). By means od Wilcoxon paired test a significant difference was found between the preoperative VAS, and the values immediately after surgery and 3 months later (Z = 7.52, p < 0.00001) when LVC was applied., and with HVC it was ( Z = 3.04, p < 0.00001), which indicates that the fast achieved pain reduction remained stable during the 3 month follow-up. The vertebroplasty is a safe and efficient surgical method in treatment of compressive vertebrae fractures which do not react to the conventional method of treatment. This method, when HVC is applied, shows significantly less complications related to cement leakage.     

Influence of maternal pregravid weight, height and body mass index on birth weight of male and female newborns

The study included 2300 healthy couples and their healthy newborns delivered vaginally from singleton, normal term (37-42 weeks) pregnancies in Sibenik, Zadar and Split (Croatia). Both fathers and mothers of male newborns were older and had a higher weight than those of female newborns (p < 0.05). Gestational age and birth weight were higher in male than female newborns (p < 0.001). Increasing maternal pregravid weight led to increasing birth weight of both male and female newborns (p < 0.001). Furthermore, increasing maternal height and body mass index resulted in increasing birth weight of male and female newborns (p < 0.001). Thus, the fathers and mothers of male infants were older than those of female infants (p < 0.05), and increasing pre-gravid body weight, body height and body mass index were associated with a higher birth weight in both male and female newborns.     

The quantitative analysis of the vascularization following two basic auditory canal skin incisions

Three groups of nine patients each were analyzed. The first two groups consisted of those that underwent tympanoplastic due to chronic inflammation of middle ear. Two different standard auditory canal skin incisions were applied, i.e. tympanomeatal flap (TMF) or vascular strip (VS). The third control group consisted of non-operated patients. All the operated patients were subjected to a quantitative analysis of the auditory canal revascularization by means of the Weibel stereological test method, i.e. the B 100 double network system. The density of capillaries, arterioles, venulolymphatic spaces and a total volume density of all vascular elements of the auditory canal skin were measured. The obtained results of vascularization were compared with those of the target control group. It was found out that there were no significant differences in vascularization of auditory canal skin between TMF and VS patients from one side and the control group on the other side.     

<Emphasis Type="Italic">INFLORESCENCE DEFICIENT IN ABSCISSION-like</Emphasis> is an abscission-associated and phytohormone-regulated gene in flower separation of <Emphasis Type="Italic">Lupinus luteus</Emphasis>

Abscission is a natural process that occurs to facilitate shedding of no longer needed organs, but on the other hand, can be triggered by certain environmental conditions, e.g. biotic or abiotic stresses. Regardless of the stimuli, organ shedding takes place specifically at the abscission zone (AZ). A signaling pathway that controls this process in Arabidopsis thaliana from ligand to receptors has been proposed. However, knowledge concerning the influence of plant hormones on these molecular elements still remains enigmatic. Excessive and premature flower abscission in the crop species Lupinus luteus L. is a process of substantial interest to the agricultural industry, as it can affect yield. Our strategy combined molecular studies, comprehensive ultrastructural and histological analysis, as well as exogenous hormone treatment to describe the contribution of the Lupinus IDA-like gene in flower abscission. In the AZ of the naturally abscised flowers, the differentiation of morphologically distinct cells characterized by progressive degradation processes was accompanied by LlIDL mRNA accumulation. A similar effect was observed following early steps of AZ activation and after abscisic acid or ethylene treatments. These phytohormones, previously pointed out as key stimulators of flower separation, altered the temporal expression pattern of LlIDL. Exogenous EPIP peptide synthesized on the basis of LlIDL sequence, significantly increased flower abortion rate, which indicates that this motif governs protein activity. In conclusion, our data provide new evidence for LlIDA involvement in both the early and late events of flower abscission supported by detailed spatiotemporal characterization of AZ cell structure and ultrastructure.     

Influence of Mannosylation on Immunostimulating Activity of Adamant‐1‐yl Tripeptide

The mannosylated derivative of adamant‐1‐yl tripeptide (D ‐(Ad‐1‐yl)Gly‐L ‐Ala‐D ‐isoGln) was prepared to study the effects of mannosylation on adjuvant (immunostimulating) activity. Mannosylated adamant‐1‐yl tripeptide (Man‐OCH₂CH(Me)CO‐D ‐(Ad‐1‐yl)Gly‐L ‐Ala‐D ‐isoGln) is a non‐pyrogenic, H₂O‐soluble, and non‐toxic compound. Adjuvant activity of mannosylated adamantyl tripeptide was tested in the mouse model with ovalbumin as an antigen and in comparison to the parent tripeptide and peptidoglycan monomer (PGM, β‐D ‐GlcNAc‐(1→4)‐D ‐MurNAc‐L ‐Ala‐D ‐isoGln‐mesoDAP(εNH₂)‐D ‐Ala‐D ‐Ala), a well‐known effective adjuvant. The mannosylation of adamantyl tripeptide caused the amplification of its immunostimulating activity in such a way that it was comparable to that of PGM.