Preclinical Study of Therapeutic Efficacy of a New Russian Radiopharmaceutical 177Lu-DOTA-PSMA.

The therapeutic efficacy of a Russian radiopharmaceutical 177Lu-DOTA-PSMA was studied in vivo using male BALB/c nu/nu (nude) mice with prostate carcinoma 22Rv1 xenografts by tumor growth inhibition criterion. The mean tumor volumes in mice treated with 177Lu-DOTA-PSMA were significantly lower than in animals of the control group. There were no significant differences in the values of tumor growth inhibition between the groups of animals receiving 3.7 or 7.4 MBq of 177Lu-DOTA-PSMA.

Biodistribution of 68Ga-NODA-Aminoglucose in Intact and Tumor-Bearing Mice.

We studied the biodistribution of 68Ga-NODA-aminoglucose (68Ga-NODA-AG) in normal mice and mice with experimental model of colon adenocarcinoma tumor. It was shown that 68Ga-NODA-aminoglucose was retained in the tumor for 3 h after injection and demonstrated high level of accumulation in the tumor. Rapid clearance of radioactivity from other organs was observed. The results suggest that 68Ga-NODA-aminoglucose is a promising agent for tumor visualization by positron emission tomography.

A Comparative Study of the Pharmacokinetics of Bis- and Pentaphosphonic Acids Labeled with Gallium-68 in Rats with Experimental Model of Bone Callus.

We analyzed biodistribution of 68Ga-labeled hydroxyethylidenediphosphonic acid (68Ga-HEDP) and diethylenetriaminepentakis(methylenephosphonic acid) (68Ga-DTPMP) in Wistar rats with experimental model of bone callus. It was shown that the content of 68Ga-DTPMP and 68Ga-HEDP in bone callus was ~1.5-fold higher than in intact femur. 68Ga-DTPMP was characterized by higher stability in vivo, higher uptake in the bone tissue, and lower uptake in others visceral organs in comparison with 68Ga-HEDP. Thus, 68Ga-DTPMP had more suitable pharmacokinetic properties than 68Ga-HEDP.

Experimental Study of the Biodistribution of New Bone-Seeking Compounds Based on Phosphonic Acids and Gallium-68.

We investigate biodistribution of gallium-labeled hydroxyethylidenediphosphonic acid (68Ga-HEDP) and diethylenetriaminepentakis(methylenephosphonic acid) (68Ga-DTPMP) in intact Wistar rats. It was shown that 68Ga-DTPMP accumulated mainly in the bone tissue providing high femur/blood and femur/muscle ratios and had high stability in vivo. In contrast, 68Ga-HEDP was characterized by low stability and high uptake of radioactivity in blood throughout the study. So 68Ga-DTPMP can be considered as a new prospective radiotracer in oncology for imaging bone tissue metastasis by positron emission tomography.

[[correlation between macro- and micro-stability C(H)2 domains of human IgG2 and their biological activity. II. Calculation of thermodynamic functions characterizing domains stability].

The thermodynamic parameters of the stabilization of the native structure C(H)2 domains of human myeloma immunoglobulin LOM and SIN second subclass and their firstly obtained hFc fragments were determined using the methods of scanning microcalorimenry. A decrease in the termal stability and energy stability of the native of these domains in the intact proteins correlated in the "phisiological" range of temperatures (20-37 degrees C), mainly, with entropy factor.

Role of cis- and trans-interactions in manifestations of amyloidogenic properties of variable domains of Bence-Jones proteins TIM and LUS.

Intact Bence-Jones proteins TIM and LUS under simulated physiological conditions (10 mM phosphate buffer, pH 7.0, 100 mM NaCl, 37°C) did not display amyloidogenic properties. However, their isolated variable domains exhibit these qualities in full measure. Therefore, both intact proteins and their variable domains were studied using a complex of physical methods (scanning microcalorimetry, analytical centrifugation, optics) that allowed us to assess the stability of their tertiary and quaternary structures. The experimentally obtained thermodynamic functions indicated that the stability of isolated variable domains of TIM and LUS was comparable to the stability of similar domains in amyloidogenic proteins described earlier. However, inside the whole protein their stability was comparable to the stability of VL domains of ordinary Bence-Jones proteins. The decreased stability of the isolated variable domains of TIM and LUS was shown to be due both to weak interactions between a pair of variable domains (trans-interaction) and to a natural lack of interaction with the constant domains (cis-interaction).

Measurement of muon capture on the proton to 1% precision and determination of the pseudoscalar coupling gP.

The MuCap experiment at the Paul Scherrer Institute has measured the rate Λ(S) of muon capture from the singlet state of the muonic hydrogen atom to a precision of 1%. A muon beam was stopped in a time projection chamber filled with 10-bar, ultrapure hydrogen gas. Cylindrical wire chambers and a segmented scintillator barrel detected electrons from muon decay. Λ(S) is determined from the difference between the µ(-) disappearance rate in hydrogen and the free muon decay rate. The result is based on the analysis of 1.2 × 10(10) µ(-) decays, from which we extract the capture rate Λ(S) = (714.9 ± 5.4(stat) ± 5.1(syst)) s(-1) and derive the proton's pseudoscalar coupling g(P)(q(0)(2) = -0.88 m(µ)(2)) = 8.06 ± 0.55.

[Thermodynamic parameters of stabilization in a compact form of the Caf1(13-149) subunit from Yersinia pestis].

With a number of experimental methods (circular dichroism, viscosity, intrinsic fluorescence and fluorescence labelling) the conformational folding-unfolding transitions in a compact monomeric form of the Caf1(13-149) subunit were studied under the action of guanidine hydrochloride in the temperature range from 5 to 45 degrees C. It has been shown that transitions always occur between two major states (unfolded and compact). It has made it possible to determine all main thermodynamic functions that characterize the compact state of the Caf1(13-149) subunit: temperature stability T(m), the free energy of stabilization deltaG(st), enthalpy deltaH(tr) and heat capacity jump deltaC collapse of the structure. Data obtained have been confirmed by an independent experiment on melting of fluorescently labeled proteins.

[The internal cavities of pike alpha-parvalbumin probably contain water].

The kinetics of hydrogen exchange of pike a-parvalbumin was investigated using the method of infrared spectroscopy (sensitive to the amide hydrogen atoms in the peptide) and radioisotope method (sensitive to all labile hydrogen atoms). Ultraslow exchangeable hydrogen atoms were found to be substantially less in the first case than in the second one. Taking into account that the internal cavities in the parvalbumin are formed by hydrophobic amino acid residues, devoid of labile hydrogen atoms, it is possible to make the most appropriate assumption, namely, these cavities contain water molecules, hydrogen atoms of which are ultraslow exchangeable.

[Stabilization energy of the compact Caf1(13-149) subunit from Yersinia pestis].

It has been shown by a variety of methods (circular dichroism, viscosimetry, intrinsic fluorescence, and fluorescence of labels) that, as in the case of small globular proteins the folding-unfolding transition in the Caf1(13-149) subunit under the action of two denaturants (urea and 1,3-dimethylurea) occurs between two major states (unfolded and compact). However, the free energy of the compact structure is only 8/9-9/2 kJ/mol (similar values for single-domain small proteins are in the range of 21-63 kJ/mol).

Measurement of the positive muon lifetime and determination of the Fermi constant to part-per-million precision.

We report a measurement of the positive muon lifetime to a precision of 1.0 ppm; it is the most precise particle lifetime ever measured. The experiment used a time-structured, low-energy muon beam and a segmented plastic scintillator array to record more than 2×10(12) decays. Two different stopping target configurations were employed in independent data-taking periods. The combined results give τ(µ(+)) (MuLan)=2 196 980.3(2.2) ps, more than 15 times as precise as any previous experiment. The muon lifetime gives the most precise value for the Fermi constant: G(F) (MuLan)=1.166 378 8(7)×10(-5) GeV(-2) (0.6 ppm). It is also used to extract the µ(-)p singlet capture rate, which determines the proton's weak induced pseudoscalar coupling g(P).

[Hydration of the compact and extended forms of pFh fragments from IgG3 Kuc and Sur].

It has been shown using scanning microcalorimetry and densitometry that partial specific heat and specific partial volume of two pFh fragments of IgG3 increase during the decay of its tertiary structure, the secondary structure, the double poly-L-proline helix, being unchanged. This effect may be explained by a high degree of hydration, which increases on globule decompactization due to increased accessibility of peptide groups of the helix to solvent.

[The influence of interdomain interaction on the amyloidogenic properties Bence-Jones proteins].

Isolated constant domains from two Bence-Jones proteins VAD and BIR able to form amyloid fibrils, whereas only the first of them to keep specific ability of the intact protein. Studies of conformation and stability of these proteins by scanning microcalorimetry, circular dichroism, fluorescence and analytical centrifugation at physiological conditions (10 mM phosphate buffer, pH 7.0, 100 mM NaCl) showed that the stability of isolated pair of constant domains (C(L)-C(L)) VAD and BIR is reduced by compared with standard (nonamyloidogenic) Bence-Jones protein. However, in the intact protein BIR stability of his constant domains increases sharply, which correlated with the loss of the protein ability to form amyloid fibrils.

[The unusual thermodynamic properties of compact forms pFh fragments (hinge region) IgG3 Kuc and Sur].

pFh fragments from the hinge region of human IgG3 Kuc and Sur can fold into compact form, resulting the formation of proteins with secondary (super-secondary) structure, which is represented almost exclusively double poly-L-proline helix. It was demonstrated by several methods that the thermal denaturation of compact form pFh fragment (hinge region) IgG3 Kuc and Sur occurs in two stages. The "two-state" model described the disintegration of the compact structure with preservation of the secondary structure (double poly-L-proline helix). In the second stage melts itself helix consisting of four cooperative units, which are formed by the sections with a high content of proline residues. Poliproline conformation of secondary structure and large number of disulfide bonds is responsible for high specific enthalpy of denaturation and high thermal stability.

[A protein with missing information about its tertiary structure folds into the compact globular structure].

It has been shown by the methods of hydrodynamics (equilibrium ultracentrifugation, velocity sedimentation, intrinsic viscosity) that a fragment of the structural protein Cafl (Cafl 13.149) from the pili-like fibril Yersinia pestis is in the monomeric state and is capable of forming the compact ternary structure spontaneously, without the involvement of chaperone or other subunits. This happens despite the fact that some information about the ternary structure of this protein is provided in fibrils by the "sticky" segment Alal-Thr12 of the neighboring subunit. As previously shown, it is this segment of another molecule in the norm that is an important element of the ternary structure of the subunit itself since it interacts with the acceptor cleft and participates in the formation of the hydrophobic core.

[Abdominal cavity adhesions. Some issues of pathogenesis, prophylaxis and treatment].

The abdominal cavity adhesions (ACA) constitute frequent consequence of various abdominal cavity diseases and traumas and frequent cause of the abdominal adhesive disease and its complications. In spite of the known pathogenesis of ACA, the surgeons had failed throughout the decades of years to find out the measures and methods of its prophylaxis. There are several causes of such a situation and the main of them is that ACA in its origin constitutes a philogenetically developed defense biologic reaction of organism. Because of the fact, that an organism constitutes the self-regulated biological system, any external inputs (including the treatment), directed on qualitative or quantitative signs of these reactions, meet systemic counteraction and become annihilated. The forced overcome of such a counteraction may cause the development of severe systemic disorders in organism. The only prophylactic measures against ACA, which were already tested throughout the time, are the tactical and technical methods, promoting the reduction of severity of morphological changes in peritoneum and abdominal organs, thus causing reduction of natural reaction of organism. When the adhesions formation is inevitable it is necessary to apply surgical methods of governing such a process, and omentoparietopexy may constitutes one of such methods.

[Thermodynamic and hydrodynamic study of Bence-Jones proteins].

Four Bence-Jones proteins were investigated by CD, fluorescence and analytical ultracentrifugation methods at physiological conditions (10 mM phosphate buffer, pH 7.0, 100 mM NaCl). A joint analysis of optical melting curves for proteins and their fragments were demonstrated that protein VAD has reduced stability of its constant half, which correlates with the ability of both intact protein and its constant, rather than variable part to form amyloid fibrils. Data are reported which support the viewpoint that the detected decrease in the stability is caused by abnormal interaction between a pair of constant domains C(L).

[Fibrillar part of C1q factor from the complement system has a great amount of bound water].

The mass of sC1q-CLR fragments from the fibrillar part of the C1q factor from the complement system was determined using high- and low-rate centrifugation. It is shown that this value is essentially higher than the value expected from the amino acid and hydrocarbon compositions. In addition, these fragments have an unusually high partial specific volume. These data support the earlier suggested model according to which the N-terminal part of the fibrillar structure contains an abnormal large amount of bound water.

Improved measurement of the positive-muon lifetime and determination of the Fermi constant.

The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector array. The result, tau(micro)=2.197 013(24) micros, is in excellent agreement with the previous world average. The new world average tau(micro)=2.197 019(21) micros determines the Fermi constant G(F)=1.166 371(6)x10(-5) GeV-2 (5 ppm). Additionally, the precision measurement of the positive-muon lifetime is needed to determine the nucleon pseudoscalar coupling g(P).

Measurement of the muon capture rate in hydrogen gas and determination of the proton's pseudoscalar coupling gP.

The rate of nuclear muon capture by the proton has been measured using a new technique based on a time projection chamber operating in ultraclean, deuterium-depleted hydrogen gas, which is key to avoiding uncertainties from muonic molecule formation. The capture rate from the hyperfine singlet ground state of the microp atom was obtained from the difference between the micro(-) disappearance rate in hydrogen and the world average for the micro(+) decay rate, yielding Lambda(S)=725.0+/-17.4 s(-1), from which the induced pseudoscalar coupling of the nucleon, g(P)(q(2)=-0.88m(2)(micro))=7.3+/-1.1, is extracted.