Blood Loss Management in Primary Hip Surgery: Is Reinfusion drain A Feasible Option in Maintaining Hemoglobin Levels?

The management of blood loss in primary hip arthroplasty is a controversial topic. Aim: To evaluate the efficacy of reinfusion drains in terms of hemoglobin levels and volume of red blood cell transfused postoperatively. Material and Methods: 295 patients who underwent primary hip arthroplasty were retrospectively assessed. After applying the exclusion criteria, 94 patients were included in the study and were divided into two groups: 45 patients received a reinfusion drain and 49 a suction drain. The following were analyzed: demographic characteristics of patients, preoperative hemoglobin level, 12-h and 24-h postoperative hemoglobin levels and their variations, number of transfused units of packed red blood cells, and postoperative complications. Results: Kruskal Wallis analysis revealed the homogeneity of the study groups (Chi-square=2.40, df=2, p=0.301). A statistically significant lower decline in mean Hb24 was found in suction drain group (p=0.001). Kruskal Wallis test revealed a significantly more frequent postoperative use of a higher number of packed red blood cell units in the suction drain group (Chi-square=28.70, df=2, p=0.001) compared to reinfusion drain group. Conclusions: We failed to demonstrate the superiority of reinfusion drains versus suction drains in maintaining hemoglobin levels.

Evaluation of the pharmacological descriptors related to the induction of antidepressant activity and its prediction by QSAR/QRAR methods.

Antidepressants are psychiatric agents used for the treatment of different types of depression, being at present amongst the most commonly prescribed drugs, while their effectiveness and adverse effects are still the subject of many studies. To reduce the inefficiency of known antidepressants caused by their side-effects, many research efforts have recently focused on the development of improved strategies for new antidepressants drug design. For this reason it is necessary to apply very fast and precise techniques, such as QSAR (Quantitative Structure-Activity Relationships) and QRAR (Quantitative Retention-Activity Relationship), which are capable to analyze and predict the biological activity for these structures, taking in account the possible changes of the molecular structures and chromatographic parameters. We discuss the pharmaceutical descriptors (van der Waals, electrostatic, hydrophobicity, hydrogen donor/acceptor bond, Verloop's parameters, polar area) involved in QSAR and also chromatographic parameters involved in QRAR studies of antidepressants. Antidepressant activities of alkanol piperazine, acetamides, arylpiperazines, thienopyrimidinone derivatives (as preclinical antidepressants) and also the antidepressants already used in clinical practice are mentioned.

Dosimetric characteristics of electron beams produced by a mobile accelerator for IORT.

Energy and angular distributions of electron beams with different energies were simulated by Monte Carlo calculations. These beams were generated by the NOVAC7 system (Hitesys, Italy), a mobile electron accelerator specifically dedicated to intra-operative radiation therapy (IORT). The electron beam simulations were verified by comparing the measured dose distributions with the corresponding calculated distributions. As expected, a considerable difference was observed in the energy and angular distributions between the IORT beams studied in the present work and the electron beams produced by conventional accelerators for non-IORT applications. It was also found that significant differences exist between the IORT beams used in this work and other IORT beams with different collimation systems. For example, the contribution from the scattered electrons to the total dose was found to be up to 15% higher in the NOVAC7 beams. The water-to-air stopping power ratios of the IORT beams used in this work were calculated on the basis of the beam energy distributions obtained by the Monte Carlo simulations. These calculated stopping power ratios, s(w,air), were compared with the corresponding s(w,air) values recommended by the TRS-381 and TRS-398 IAEA dosimetry protocols in order to estimate the deviations between a dosimetry based on generic parameters and a dosimetry based on parameters specifically obtained for the actual IORT beams. The deviations in the s(w,air) values were found to be as large as up to about 1%. Therefore, we recommend that a preliminary analysis should always be made when dealing with IORT beams in order to assess to what extent the possible differences in the s(w,air) values have to be accounted for or may be neglected on the basis of the specific accuracy needed in clinical dosimetry.

Comparative study of some energetic and steric parameters of the wild type and mutants HIV-1 protease: a way to explain the viral resistance.

Because, in vivo, the HIV-1 PR ( HIV-1 protease) present a high mutation rate we performed a comparative study of the energetic behaviors of the wild type HIV-1 PR and four type of mutants: Val82/Asn; Val82/Asp; Gln7/Lys, Leu33/Ile, Leu63/Ile; Ala71/Thr, Val82/Ala. We suggest that the energetic fluctuation (electrostatic, van der Waals and torsion energy) of the mutants and the solvent accessible surface (SAS) values can be useful to explain the viral resistance process developed by HIV-1 PR. The number and localization of enzyme mutations induce important modifications of the van der Waals and torsional energy, while the electrostatic energy has an insignificant fluctuation. We showed that the viral resistance can be explored if the solvent accessible surfaces of the active site for the mutant structures are calculated. In this paper we have obtained the solvent accessible surface for a group of 15 mutants (11 mutants obtained by Protein Data Bank (PDB) file, 4 mutants modeled by CHARMM software) and for the wild type HIV-1 PR). Our study try to show that the number and localization of the mutations are factors which induce the HIV-1 PR viral resistance. The larger solvent accessible surface could be recorded for the point mutant Val 82/Phe.

Behavior of small thyroid cancers found by screening radiation-exposed individuals.

Thyroid cancers detected by screening irradiated individuals are often small and of uncertain clinical significance. We retrospectively analyzed the effect of screening in a cohort of 4296 individuals exposed to radiation as children in the 1940s and 1950s and followed by us from 1974 until the present. We compared the thyroid cancers diagnosed before 1974 (122 cases, routine care) with the cancers found in subjects screened by us after 1974 (172 cases, screened), using cancer recurrence as the end point. Screening included a thyroid scan or, more recently, thyroid ultrasound. As expected, many of the cancers found by screening were very small (52% were <10 mm), but the range of tumor sizes overlapped those found by routine care. The recurrence rate was significantly lower in the cases found by screening, but when the comparison was limited to cancers 10 mm or larger, no difference in the recurrence rates was seen. This would suggest that the lower recurrence rate observed for small thyroid cancers detected at screening was due to earlier diagnosis rather than more effective treatment. By univariate analysis, four factors were associated with an increased risk of recurrence of small (<10 mm) thyroid cancers: short latency (i.e. a shorter time interval between the radiation exposure and the first thyroid surgery), lymph node metastases present at diagnosis, multifocal cancers, and higher radiation dose. In a multivariate analysis combining the four risk factors, only short latency was significant. As thyroid cancers that escape detection by routine means should be diagnosed at screening, and both large and small thyroid cancers have the potential to recur, screening may be of value, but only if groups with a sufficiently high prevalence of thyroid cancer can be identified to offset the adverse effects of unnecessary treatment due to false positive results.

Atomic detail peptide-membrane interactions: molecular dynamics simulation of gramicidin S in a DMPC bilayer.

Molecular dynamics simulations have been performed of the sequence-symmetric cyclic decapeptide antibiotic gramicidin S (GS), in interaction with a hydrated dimyristoylphosphatidylcholine (DMPC) bilayer, and the results compared with a "control" simulation of the system in the absence of GS. Following experimental evidence, the GS was initially set in a single antiparallel beta-sheet conformation with two Type II' beta-turns in an amphiphilic interaction with the membrane. This conformation and position remained in the 6.5 ns simulation. Main-chain dihedrals are on average approximately 26 degrees from those determined by NMR experiment on GS in dimethylsulfoxide (DMSO) solution. Sequence-symmetric main-chain and side-chain dihedral angle pairs converge to within approximately 5 degrees and approximately 10 degrees, respectively. The area per lipid, lipid tail order parameters, and quadrupole spin-lattice relaxation times of the control simulation are mostly in good agreement with corresponding experiments. The GS has little effect on the membrane dipole potential or water permeability. However, it is found to have a disordering effect (in agreement with experiment) and a fluidifying effect on lipids directly interacting with it, and an ordering effect on those not directly interacting.

Spontaneous electrical potential oscillation on a filter impregnated with soybean lecithin placed between identical solutions of alanine.

Filters impregnated with soybean lecithin, placed between two identical aqueous alanine solutions, display spontaneous electric potential oscillations. Alanine solutions used in a large concentration range from 1 mM to 1 M produce damped oscillatory behaviour with an exponential decay in time. The dependence of decay time on concentration shows saturation behaviour which is well fitted with a sigmoidal curve. Power spectra obtained by Fourier transform show peaks specific for each concentration. When fitted with a Lorentzian curve in the peak domain, the centre of the peak height and width at half height could be extracted. All these parameters depend on alanine concentration in a saturating pattern.

An octamer-binding site is crucial for the activity of an enhancer active at the embryonic met-/mesencephalic junction.

An enhancer sequence found in the Protease Nexin-1 (PN-1) gene was shown to drive lacZ expression specifically at the met-/mesencephalic junction in transgenic mouse embryos. A functional study of this enhancer has been performed to better understand the mechanisms regulating isthmic gene expression. An octamer-binding site for POU domain factors was found to be crucial for the activity of the enhancer in vivo. Comparative expression studies of POU domain factors, electrophoretic mobility shift assays and transient transfection experiments, strongly suggest that Brn-1/-2 regulate the enhancer activity in vivo. In addition, in vitro experiments indicated that FGF-8 was required for the maintenance of the enhancer activity, but not for the synthesis of Bn-1/-2. The data represents the first functional evidence for a role of POU factors in the regulation of met-/mesencephalic gene expression. It also implies that at least two regulatory pathways, namely the FGF-8 signaling and the octamer-binding site pathway, synergistically interact to control the PN-1 enhancer activity in vivo.

Characteristics of ionic transport processes in fish intestinal epithelial cells.

A general mathematical version of the cell model of a leaky epithelium for the NaCl absorption is presented, analysed and integrated numerically. The model consists in the adequate differential equations that describe the rate of change of the intracellular ion concentrations and are expressed in strict accordance with the law of mass conservation. The model includes many state variables representing ion concentrations, the cell volume, and membrane potentials. Ion movements are described by the Michaelis-Menten kinetics or by the constant field flux equation (Goldman-Hodgkin-Katz). In this paper, we model the intracellular ion concentrations, change in the cell volume, the transmembrane flux and membrane potentials of intestinal epithelium of both fresh water and sea water fish, and generate several simulations (in both the steady state and the transient state analysis) that appear to accord with prior experimental data in this area. For the ion movements of the sea water fish intestine, there were included a Na+/K+ pump, a K(+)-Cl- symport system, the K+ and Cl- channels in the basolateral membrane, whereas a Na(+)-K(+)-2Cl- cotransporter for NaCl absorption and K+ channels are located in the apical membrane. In the fresh water fish intestinal cells, the NaCl absorption is performed by two coupled antiporters Na+/H+ and Cl-/HCO3- presumably responsible for the intracellular pH regulation. In this type of cells, Na+ and K+ channels are located within the apical membrane, whereas Cl- channels are located within the basolateral membrane. The osmotically induced water transport across the apical and basolateral membranes has been taken into account as well. The simulations plot the steady state values for membrane potential difference, short-circuit current and intracellular ionic concentrations using the magnitude of the transmembrane flux through the Na+/K+ pump and Na(+)-K(+)-2Cl- cotransporter, or the basolateral Cl- permeability as dependent variables. The model behaves appropriately with regard to several experimental studies regarding the hyperpolarization (sea water fish intestine) and depolarization (fresh water fish intestine) of the apical membrane potential and inhibition of the short-circuit flux with reduced NaCl absorption. The model is also used to make several analytical predictions regarding the response of the membrane potential and ionic concentrations to variations in the basolateral Cl- flux. Furthermore, maintaining conservation of both mass and electroneutrality and taking into account the osmolar forces is an important advantage, because it allows a rigorous analysis of the relationship between membrane potential difference, volume and flux. The model can be used in the analysis and planning of the experiments and is capable of predicting the instantaneous values of ionic fluxes and intracellular concentrations and of cell volume.

Fourier analysis of potential oscillations of a liquid membrane for the discrimination of taste substances.

Electrical potential oscillations were obtained across a liquid membrane composed of nitrobenzene/picric acid placed between two aqueous phases in the presence of various taste (i.e. salty, sweet and bitter) substances. The influence of these compounds on electrical oscillations was studied using Fourier analysis to establish a "fingerprint" of the substance that can be correlated with its taste index. Various concentrations of each substance were tested to obtain a Fourier spectrum with discrete peaks which can be further processed. The electrical oscillations consisted of a number of weak damped oscillators, and the Fourier spectra of these signals were found to have a number of discrete peaks of decreasing amplitude at low frequencies (0-0.5 Hz). A correlation of the frequency of the first peak of the Fourier spectrum with the taste index was found for bitter substances, whereas for salty substances the amplitude of the first two peaks of the spectrum was correlated with the taste index.

Two-dimensional crystallization of the light-harvesting complex from Rhodospirillum rubrum.

Homogeneous detergent-solubilized B873 light-harvesting complexes from a carotenoid-less mutant of the purple non-sulfur bacterium, Rhodospirillum rubrum G9, were reassembled spontaneously into two-dimensional (2D) hexagonal arrays during extensive and controlled dialysis. As the complexes contain only 1 to 2 mol phospholipid per mol alpha beta dimer, the arrays formed by a self assembly process are primary due to protein-protein interactions. The hexagonal lattices were analyzed by negative stain electron microscopy and digital image processing. They exhibited a unit cell size of 12.3 nm, in close agreement with the particle diameter of the active photo-unit in native chromatophore membranes. The unit cell contains a central 5 nm stain-filled depression, embraced by a ring with an outer diameter of 10 nm.

Procaine incorporation into human erythrocyte membrane--a spin label study.

The positioning of procaine among the components of human erythrocyte membranes was investigated by electron paramagnetic resonance (EPR) using several spin labelled molecules: fatty acids 5-, 12- and 16-doxyl-stearic acids (5DSA, 12DSA, 16DSA), procaine (SLP) and a quaternary ammonium salt (CAT4). It was proved that while procaine significantly modified EPR parameters of both CAT4 and 5DSA, it had no effect at the level of the twelfth or sixteenth carbon atom of the membrane lipid chains. Simultaneous incorporation of 5DSA and SLP and SLP in erythrocyte membranes revealed a shorter than 10 A distance between paramagnetic centers of 5DSA and SLP. It is inferred that procaine interacts with the membrane not only at lipid water interface, but also (at least) up to the fifth carbon atom of the hydrophobic tail of phopolipids. Procaine inclusion does not change the transition point (40 degrees C) at which a break appears in the temperature dependence of the erythrocyte volume, hence no strong interaction between the procaine and the cytoskeleton or the integral proteins responsible for this phase transition occurs. In the temperature domain of 25-42 degrees C, procaine seems to be freely diffusible within the membrane (Debye model can be applied).

The action of mouse liver and lung homogenates on the ESR signal of a spin-labelled antiviral compound.

A spin-labelled derivative of amantadine was prepared and added to mouse liver and lung homogenates in vitro in the presence and in the absence of inhibitors of oxidative enzymes; the kinetics of the quenching of ESR signals was followed up in different experimental variants.

Investigations of the presence of serum antibodies to Epstein-Barr virus in patients with various tumors.

Serum samples from 150 patients with various malignant or benign tumors and from 20 clinically healthy subjects were tested by indirect immunofluorescence (IF) reaction for the presence of specific antibodies to Epstein-Barr-virus-determined viral capsid antigen (EB VCA). The IF test-carried out in multitest-slide EB3 and Raji cell preparations-revealed antibodies to EB VCA in 102 of the patients with tumors and in 4 of the healthy persons.

Specific protection against bovine leukemia virus infection conferred on cattle by the Romanian inactivated vaccine BL-VACC-RO.

The Romanian BL-VACC-RO vaccine against bovine leukemia virus (BLV) infection was prepared with ethylenimine-inactivated BLV obtained from persistently infected cell lines. Intramuscular administration of two vaccine doses (each containing 0.40 mg virus glycoprotein with adjuvant), 2 weeks apart, conferred protection against challenge infection with BLV on 18 of the 20 vaccinated calves. Two calves were not protected, in spite of their positive serologic response to vaccination. The results demonstrate the efficiency of the BL-VACC-RO vaccine in preventing BLV infection.

Detection of C-type virus by immunoferritin technique in bat lung cell line chronically infected with bovine leucosis virus.

Reported in this paper are morphological studies and tests for the detection of Type-C particles from a line of bat lung cells chronically infected with bovine leucosis virus. The immunoferritin technique was used. Ferritin labelling of Type-C particles was regularly accompanied by black-spot arrangement of ferritin around the virus envelope, which provided evidence to the specificity of this immunochemical technique.