The role of psychological characteristics of the personality of patients with colorectal cancer in the timeliness of diagnosis verification and prognosis of disease outcome.

OBJECTIVE: Colorectal cancer (CRC) has become the third most commonly diagnosed type of cancer in the world. Based on the risk factors for colorectal cancer (behavior, lifestyle), it is important to better understand the behavioral and psychological characteristics of the individual associated with timely seeking medical help, coping with the extreme situation of diagnosis, and the course of the disease. This determined the purpose of the study: identify the psychological characteristics of patients with colorectal cancer associated with the stage of diagnosis verification and the prognosis of disease outcome. PATIENTS AND METHODS: Coping, quality of life, and resilience, as well as clinical and sociodemographic variables were studied in 72 patients diagnosed with colorectal cancer. The design of the study involved studying the relationship between the stage of cancer and the prognosis of the outcome of the disease, as well as the role of psychological variables in the timeliness of diagnosis and predicting the outcome of cancer. RESULTS: The stage of verification of colorectal cancer is associated with the prognosis of the outcome of the cancer; the later colorectal cancer is verified, the more unfavorable the prognosis of the outcome of the oncological disease. Escape-avoidance coping is associated with the verification stage of colorectal cancer; pronounced avoidance is associated with the late verification stage. Coping strategies such as seeking social support, positive reappraisal, risk-taking, pain intensity, and role functioning significantly influence the prognosis of colorectal cancer outcomes. CONCLUSIONS: The psychological characteristics of the personality of patients with colorectal cancer have been identified, which, by determining the behavior of patients, affect the timeliness of diagnosis verification and the prognosis of the outcome of the disease.

[The psychological and environment risk factors of development of breast cancer in women residing in industrial megalopolis and rural locality].

The breast cancer hold leading position in the structure of oncological morbidity of women worldwide. The purpose of the study is to analyze contribution of psychological and environmental factors to risk of development of breast cancer in women residing in industrial metropolis and rural locality. The actuality of the study is conditioned by acquisition of new knowledge about risk factors of breast cancer. The study covered psychological factors (basic beliefs, life orientations, locus of control, coping behavior strategies, subjective assessment of quality of life, subjective age indicator, personal helplessness-independence, resilience) and environmental factor (place of urban of rural residence of women with breast cancer). The study established that in women residing in industrial metropolis the psychological risk factors are reduced indicators of basic beliefs, of quality of life and of resilience, rare application of coping strategy "Escape-Avoidance", external locus of control. Alternatively, in women residing in rural areas, psychological risk factors for breast cancer are rare application of coping strategies, reduced quality of life indicators, increased vital activity, internal level of subjective control and personal helplessness. The study results can be included in development of personalized breast cancer screening protocols and as well as considered in assessing risk of development of disease when classifying women by breast cancer risk groups.

Psychological predictors of favorable and unfavorable disease course of prostate cancer: results of a pilot study.

OBJECTIVE: The statistical data on the incidence and mortality rates from prostate cancer leave gaps in understanding the causal risk factors for the unfavorable course of the disease determined the relevance of this work, determined the purpose of the study: to identify psychological predictors of favorable and unfavorable courses of prostate cancer. PATIENTS AND METHODS: Basic beliefs, coping, quality of life, level of subjective control, resilience, life orientation, as well as socio-demographic characteristics were analyzed in 124 men with different courses of the disease. Firstly, the psychological characteristics of men with prostate cancer with a favorable or unfavorable course were compared, and secondly, psychological predictors were identified and their contribution to the course of prostate cancer was assessed. RESULTS: It has been established that high involvement as an indicator of resilience, externality in the sphere of failures, the absence of restrictions on daily life due to physical condition, and a low value of belief about control is associated with a favorable course of the disease. The involvement of a man in his own life and ongoing events, interest in his own activities, the conviction that not all events can be controlled, as well as the localization of control outside, contribute to a faster onset of remission or stabilization of the disease. CONCLUSIONS: The psychological features determine the behavior of men with prostate cancer, including the implementation of doctor's recommendations and compliance with treatment requirements, timely visits to the doctor, taking medications, which in turn determines the course of the disease and the success of treatment.

[Bowel dysfunctional microflora: clinical significance and prospects for its therapy]. / Disbakterioz kishechnika: klinicheskoe znachenie i perspektivy lecheniia.

Due to the application of complex drugs as well as synergistic action of drugs with a different mechanism of their activity, it is quite possible to restore the eubiosis of bowels. The up-to-date correction of biocenosis is an essential principle of the microecological approach to the maintenance of health in individuals and the entire population.

Catalytic acid-base groups in yeast pyruvate decarboxylase. 1. Site-directed mutagenesis and steady-state kinetic studies on the enzyme with the D28A, H114F, H115F, and E477Q substitutions.

The roles of four of the active center groups with potential acid-base properties in the region of pH optimum of pyruvate decarboxylase from Saccharomyces cerevisiae have been studied with the substitutions Asp28Ala, His114Phe, His115Phe, and Glu477Gln, introduced by site-directed mutagenesis methods. The steady-state kinetic constants were determined in the pH range of activity for the enzyme. The substitutions result in large changes in k(cat) and k(cat)/S(0.5) (and related terms), indicating that all four groups have a role in transition state stabilization. Furthermore, these results also imply that all four are involved in some manner in stabilizing the rate-limiting transition state(s) both at low substrate (steps starting with substrate binding and culminating in decarboxylation) and at high substrate concentration (steps beginning with decarboxylation and culminating in product release). With the exception of some modest effects, the shapes of neither the bell-shaped k(cat)/S(0.5)-pH (and related functions) plots nor the k(cat)-pH plots are changed by the substitutions. Yet, the fractional activity still remaining after substitutions virtually rules out any of the four residues as being directly responsible for initiating the catalytic process by ionizing the C2H. There is no effect on the C2 H/D exchange rate exhibited by the D28A and E477Q substitutions. These results strongly imply that the base-induced deprotonation at C2 is carried out by the only remaining base, the iminopyrimidine tautomer of the coenzyme, via intramolecular proton abstraction. The first product is released as CO(2) rather than HCO(3)(-) by both wild-type and E477Q and D28A variants, ruling out several mechanistic alternatives.

Catalytic acid-base groups in yeast pyruvate decarboxylase. 2. Insights into the specific roles of D28 and E477 from the rates and stereospecificity of formation of carboligase side products.

Yeast pyruvate decarboxylase (YPDC), in addition to forming its metabolic product acetaldehyde, can also carry out carboligase reactions in which the central enamine intermediate reacts with acetaldehyde or pyruvate (instead of the usual proton electrophile), resulting in the formation of acetoin and acetolactate, respectively (typically, 1% of the total reaction). Due to the common mechanism shared by the acetaldehyde-forming and carboligase reactions through decarboxylation, a detailed analysis of the rates and stereochemistry of the carboligase products formed by the E477Q, D28A, and D28N active center YPDC variants was undertaken. While substitution at either position led to an approximately 2-3 orders of magnitude lower catalytic efficiency in acetaldehyde formation, the rate of acetoin formation by the E477Q and D28N variants was higher than that by wild-type enzyme. Comparison of the steady-state data for acetaldehyde and acetoin formation revealed that the rate-limiting step for acetaldehyde formation by the D28A, H114F, H115F, and E477Q variants is a step post-decarboxylation. In contrast to the wild-type YPDC and the E477Q variant, the D28A and D28N variants could synthesize acetolactate as a major product. The lower overall rate of side-product formation by the D28A variant than wild-type enzyme attests to participation of D28 in steps leading up to and including decarboxylation. The results also provide insight into the state of ionization of the side chains examined. (R)-Acetoin is produced by the variants with greater enantiomeric excess than by wild-type YPDC. (S)-Acetolactate is the predominant enantiomer produced by the D28-substituted variants, the same configuration as produced by the related plant acetolactate synthase.

Catalytic acid-base groups in yeast pyruvate decarboxylase. 3. A steady-state kinetic model consistent with the behavior of both wild-type and variant enzymes at all relevant pH values.

The widely quoted kinetic model for the mechanism of yeast pyruvate decarboxylase (YPDC, EC 4.1.1.1), an enzyme subject to substrate activation, is based on data for the wild-type enzyme under optimal experimental conditions. The major feature of the model is the obligatory binding of substrate in the regulatory site prior to substrate binding at the catalytic site. The activated monomer would complete the cycle by irreversible decarboxylation of the substrate and product (acetaldehyde) release. Our recent kinetic studies of YPDC variants substituted at positions D28 and E477 at the active center necessitate some modification of the mechanism. It was found that enzyme without substrate activation apparently is still catalytically competent. Further, substrate-dependent inhibition of D28-substituted variants leads to an enzyme form with nonzero activity at full saturation, requiring a second major branch point in the mechanism. Kinetic data for the E477Q variant suggest that three consecutive substrate binding steps may be needed to release product acetaldehyde, unlikely if YPDC monomer is the minimal catalytic unit with only two binding sites for substrate. A model to account for all kinetic observations involves a functional dimer operating through alternation of active sites. In the context of this mechanism, roles are suggested for the active center acid-base groups D28, E477, H114, and H115. The results underline once more the enormous importance that both aromatic rings of the thiamin diphosphate, rather than only the thiazolium ring, have in catalysis, a fact little appreciated prior to the availability of the 3-dimensional structure of these enzymes.

Spectroscopic detection of transient thiamin diphosphate-bound intermediates on benzoylformate decarboxylase.

Thiamin diphosphate (ThDP)-dependent enzymes catalyze a range of transformations, such as decarboxylation and ligation. We report a novel spectroscopic assay for detection of some of the ThDP-bound intermediates produced on benzoylformate decarboxylase. Benzoylformate decarboxylase was mixed with its alternate substrate p-nitrobenzoylformic acid on a rapid-scan stopped-flow instrument, resulting in formation of three absorbing species (lambda(max) in parentheses): I(1) (a transient at 620 nm), I(2) (a transient at 400 nm), and I(3) (a stable absorbance with lambda(max) > 730 nm). Analysis of the kinetics of the two transient species supports a model in which a noncovalent complex of the substrate and the enzyme is converted to the first covalent intermediate I(1); the absorbance corresponding to I(1) is probably a charge-transfer band arising from the interaction of the thiamin diphosphate-p-nitrobenzoylformic acid covalent adduct (2-p-nitromandelylThDP) and the enzyme. The rate of disappearance of I(1) parallels the rate of formation of I(2). Chemical models suggest the lambda(max) of I(2) (near 400 nm) to be appropriate to the enamine, a key intermediate in ThDP-dependent reactions resulting from the decarboxylation of the thiamin diphosphate-p-nitrobenzoylformic acid covalent adduct. Therefore, the rate of disappearance of I(1) and/or the appearance of I(2) directly measure the rate of decarboxylation. A relaxation kinetic treatment of the pre-steady-state kinetic data also revealed a hitherto unreported facet of the mechanism, alternating active-sites reactivity. Parallel studies of the His70Ala BFD active-site variant indicate that it cannot form the complex reported by the charge-transfer band (I(1)) at the level of the wild-type protein.

Dimers generated from tetrameric phosphorylating glyceraldehyde-3-phosphate dehydrogenase from Bacillus stearothermophilus are inactive but exhibit cooperativity in NAD binding.

Tetrameric phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from Bacillus stearothermophilus has been described as a "dimer of dimers" with three nonequivalent interfaces, P-axis (between subunits O and P and between subunits Q and R), Q-axis (between subunits O and Q and between subunits P and R), and R-axis interface (between subunits O and R and between subunits P and Q). O-P dimers, the most stable and the easiest to generate, have been created by selective disruption of hydrogen bonds across the R- and Q-axis interfaces by site-directed mutagenesis. Asp-186 and Ser-48, and Glu-276 and Tyr-46, which are hydrogen bond partners across the R- and Q-axis interfaces, respectively, have been replaced with glycine residues. All mutated residues are highly conserved among GAPDHs from different species and are located in loops. Both double mutants D186G/E276G and Y46G/S48G were dimeric, while all single mutants remained tetrameric. As previously described [Clermont, S., Corbier, C., Mely, Y., Gerard, D., Wonacott, A., and Branlant, G. (1993) Biochemistry 32, 10178-10184], NAD binding to wild type GAPDH (wtGAPDH) was interpreted according to the induced-fit model and exhibited negative cooperativity. However, NAD binding to wtGAPDH can be adequately described in terms of two independent dimers with two interacting binding sites in each dimer. Single mutants D186G, E276G, and Y46G exhibited behavior in NAD binding similar to that of the wild type, while both dimeric mutants D186G/E276G and Y46G/S48G exhibited positive cooperativity in binding the coenzyme NAD. The fact that O-P dimer mutants retained cooperative behavior shows that (1) the P-axis interface is important in transmitting the information induced upon NAD binding inside the O-P dimer from one subunit to the other and (2) the S-loop of the R-axis-related subunit is not directly involved in cooperative binding of NAD in the O-P dimer. In both O-P dimer mutants, the absorption band of the binary enzyme-NAD complex had a highly decreased intensity compared to that of the wild type and, in addition, totally disappeared in the presence of G3P or 1,3-dPG. However, no enzymatic activity was detected, indicating that the formed ternary enzyme-NAD-G3P or -1, 3-dPG complex was not catalytically efficient. In the O-P dimers, the interaction with the S-loop of the R-axis-related subunit is disrupted, and therefore, the S-loop should be less structured. This resulted in increased accessibility of the active site to the solvent, particularly for the adenosine-binding site of NAD. Thus, together, this is likely to explain both the lowered affinity of the dimeric enzyme for NAD and the absence of activity.

Visual search, perception, and visual-motor skill in "healthy" children born at 27-32 weeks' gestation.

Visual-perceptual, attentional, and visual-motor skills were examined in a group of 16 school-age children, born at 27-32 gestational weeks, who had performed normally on pediatric screening tests. Compared with 16 matched full-term controls, the preterms performed poorly on only two measures: they took longer to point to the missing arc of an annulus displayed on a computer screen and failed to find targets more often in a complex visual search task. They showed no deficits on tests of visual form extraction and closure. These data suggest that in the absence of any disability that is clinically detectable, prematurity results in a cluster of small but significant visual-motor impairments that persist into middle childhood. These relate to the maintenance of attention and visual-motor coordination, though visual form perception is not measurably affected. The results are discussed in the context of current neurobiological models of visual system organization.

Kinetic mechanism of the glycogen-phosphorylase-catalysed reaction in the direction of glycogen synthesis: co-operative interactions of AMP and glucose 1-phosphate during catalysis.

We employed our newly developed, continuous, spectrophotometric method [Sergienko and Srivastava (1994) Anal. Biochem. 221, 348-355] for measuring the glycogen-phosphorylase-catalysed reaction in the direction of glycogen synthesis, utilizing varied concentrations of AMP (2-400 microM) and glucose 1-phosphate (G1P; 4 microM to 41 mM). The experimental data revealed that the enzyme catalysis exhibits sigmoidal dependence on both AMP and G1P concentrations, with Hill coefficient and EC50 values (mutually) affected by the concentrations of the above substrates. A detailed kinetic analysis of the substrate-dependent activation, as well as glucose-inhibition data, lead us to propose the following mechanistic features of the glycogen-phosphorylase-catalysed reaction. (1) The enzyme exhibits catalytic activity when two molecules of AMP and two molecules of G1P are bound to the dimeric unit. (2) The binding of one molecule of glucose (the competitive inhibitor of G1P) per dimeric unit results into a complete loss of the enzyme activity. (3) There is no restriction of binding of AMP or G1P when one of the dimeric subunits is already bound with the other ligand. For example, one or two G1P molecules can bind to the enzyme dimer when zero, one or two molecules of AMP are already bound. The magnitudes of rate and equilibrium constants for the glycogen-phosphorylase-catalysed reaction, derived from analyses of the experimental data in the light of a few selected minimal models, are presented.

Recombinant human liver medium-chain acyl-CoA dehydrogenase: purification, characterization, and the mechanism of interactions with functionally diverse C8-CoA molecules.

We offer a large scale purification procedure for the recombinant human liver medium-chain acyl-CoA dehydrogenase (HMCAD). This procedure routinely yield 100-150 mg of homogeneous preparation of the enzyme from 80 L of the Escherichia coli host cells. A comparative investigation of kinetic properties of the human liver and pig kidney enzymes revealed that, except for a few minor differences, both of these enzymes are nearly identical. We undertook detailed kinetic and thermodynamic investigations for the interaction of HMCAD-FAD with three C8-CoA molecules (viz., octanoyl-CoA, 2-octenoyl-CoA, and 2-octynoyl-CoA), which differ with respect to the extent of unsaturation of the alpha-beta carbon center; octanoyl-CoA and 2-octenoyl-CoA serve as the substrate and product of the enzyme, respectively, whereas 2-octynoyl-CoA is known to inactivate the enzyme. Our experimental results demonstrate that all three C8-CoA molecules first interact with HMCAD-FAD to form corresponding Michaelis complexes, followed by two subsequent isomerization reactions. The latter accompany either subtle changes in the electronic structures of the individual components (in case of 2-octenoyl-CoA and 2-octynoyl-CoA ligands), or a near-complete reduction of the enzyme-bound flavin (in case of octanoyl-CoA). The rate and equilibrium constants intrinsic to the above microscopic steps exhibit marked similarity with different C8-CoA molecules. However, the electronic structural changes accompanying the 2-octynoyl-CoA-dependent inactivation of enzyme is 3-4 orders of magnitude slower than the above isomerization reactions. Hence, the octanoyl-CoA-dependent reductive half-reaction and the 2-octynoyl-CoA-dependent covalent modification of the enzyme occur during entirely different microscopic steps. Arguments are presented that the origin of the above difference lies in the protein conformation-dependent orientation of Glu-376 in the vicinity of the C8-CoA binding site.

[The effect of early visual deprivation on the formation of a control system for brain states in early human ontogeny]. / Vliianie rannei zritel'noi deprivatsii na formirovanie sistemy kontrolia sostoianii mozga v rannem ontogeneze cheloveka.

Late effects of early visual deprivation on state control in sleep were studied in 23 infants with bilateral congenital cataract before and after surgery (usually, on the 6th month of life). In the course of three years 67 observations were performed. Laboratory assessments included videotaping infant sleep behaviour, recording EEG, EOG, ECG, galvanic skin response. It was shown that the early visual deprivation led to general changes in the basic mechanisms underlying state control in infancy. The sleep stages (active and quiet sleep), their duration and physiological autonomic and central characteristics were modified as compared to the age norm over a protracted period after surgery, when the visual experience became available for the infant. This type of sleep cycle can be identified as "partially perinatal sleep pattern". Revealed peculiarities of sleep cycle organization were suggested to reflect the higher level of activation in the neural arousal systems owing to the deficit of environmental stimulation during the critical stage (2-4 months) of brain development.

A continuous spectrophotometric method for the determination of glycogen phosphorylase-catalyzed reaction in the direction of glycogen synthesis.

We offer a "continuous" spectrophotometric method for the determination of the glycogen phosphorylase-catalyzed reaction in the direction of glycogen synthesis. This method relies on a coupled enzyme procedure, involving purine nucleoside phosphorylase and its chromophoric substrate, 2-amino-6-mercapto-7-methyl ribonucleoside (7-methyl-6-thioguanosine (MTGuo)), for the estimation of inorganic phosphate (M. R. Webb, Proc. Natl. Acad. Sci. USA 89, 4884-4887, 1992). We have examined the effects of the reaction components on the catalytic activities of both "primary" and "coupling" enzymes. While MTGuo exhibits no effect on the glycogen phosphorylase-catalyzed reaction, glucose 1-phosphate and AMP are partially inhibitory to nucleoside phosphorylase. However, the latter effects pose no problem as long as the coupling enzyme is maintained at a relatively higher concentration in the assay system. The coupled enzyme assay system, standardized for the measurement of glycogen phosphorlase activity, has enabled us to demonstrate explicitly that the rate of the enzyme-catalyzed reaction exhibits sigmoidal dependence on both AMP and glucose 1-phosphate concentrations. We argue that these sigmoidal profiles have been observed due to the sensitivity and precision of the present assay system.

Glyceraldehyde-3-phosphate activates auto-ADP-ribosylation of glyceraldehyde-3-phosphate dehydrogenase.

Nitric oxide was recently demonstrated to stimulate ADP-ribosylation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Our studies on the effect of glyceraldehyde-3-phosphate (GA3P), the natural substrate of dehydrogenase activity of GAPDH, indicated GA3P to be another very potent activator of ADP-ribosylation of the enzyme. GA3P was able to activate ADP-ribosylation only in the presence of DTT. The action of GA3P was associated with inhibition of GAPDH dehydrogenase activity. Ka for GA3P was at least 50-fold lower and maximal activation was somewhat higher than these values for other aldehydes that were also able to enhance GAPDH ADP-ribosylation in the presence of DTT. ADP-ribosylation was blocked by carboxamidomethylation of the essential cysteine SH-group. The bond between the prelabeled protein and ADP-ribose was resistant to hydrolysis with hydroxylamine and HgCl2, suggesting that a lysine epsilon-amino group is the target for ADP-ribosylation.

[Phosphorylation of glyceraldehyde-3-phosphate dehydrogenase]. / Fosforilirovanie glitseral'degid-3-fosfat degidrogenazy.

Phosphorylation of D-glyceraldehyde-3-phosphate dehydrogenase (GPDH) by Ca2+/phospholipid- and Ca2+/calmodulin-dependent protein kinases was shown to take place in rabbit skeletal muscle and brain extracts. The kinases could be "picked up" from the extract, using GPDH immobilized on CNBr-activated Sepharose 4B as an affinity adsorbent. Washing of the column with GPDH solutions resulted in elution of the protein kinases; the same effect was observed when anti-GPDH antibodies were used. The most effective elution took place under the conditions favouring the dissociation of the immobilized GPDH into dimers. Based on these findings, a method for purification of Ca2+/calmodulin-dependent protein kinase has been elaborated, which includes chromatography on phenyl-Sepharose to separate the kinase from GPDH. The susceptibility of GPDH to phosphorylation by tissue protein kinases was confirmed by analyses of GPDH preparations purified from rabbit muscle for endogenous phosphate content: 0.7-1.5 moles of covalently bound phosphate were found per mole of the enzyme.

[State of microcirculation channel in the area of laser "welded" anastomosis of the small intestine]. / Sostoianie mikrotsirkuliatornogo rusla v oblasti lazernogo "svarnogo" tonkokishechnogo anastomoza.

Experiments were conducted with CO2 and AIG laser on neodymium to study the condition of microcirculation and the degree of its disturbance in the wall of the small intestine in formation of a laser "welded" entero-enteral and termino-terminal anastomosis. The microcirculatory disorders and their extent were found to be directly dependent on the degree of the thermal effect and the width of the coagulation zone in the region of the suture. The results of the experiment confirmed that the suggested powers of the laser effect on the intestinal wall were optimal.

D-glyceraldehyde-3-phosphate dehydrogenase purified from rabbit muscle contains phosphotyrosine.

Homogeneous preparations of D-glyceraldehyde-3-phosphate dehydrogenase purified from rabbit muscle were found to contain 0.2-0.7 moles of covalently bound phosphate per mole of the enzyme. With the use of anti-phosphotyrosine antibodies, evidence was obtained that the enzyme is phosphorylated at tyrosine residues.

Nitroprusside stimulates the cysteine-specific mono(ADP-ribosylation) of glyceraldehyde-3-phosphate dehydrogenase from human erythrocytes.

In human erythrocyte membranes incubated with [adenylate-32P]NAD the 36 kDa protein is predominantly labeled. The labeling is greatly stimulated by nitroprusside in the presence of dithiothreitol. We have purified the 36 kDa protein and identified this modification as cysteine-specific mono(ADP-ribosylation) because: (i) labeling occurred only when [32P]NAD was replaced by adenine[U-14C]NAD, but not by [carbonyl-14C]NAD; (ii) treatment of the prelabeled protein with snake venom phosphodiesterase led to releasing 5'-[32P]AMP; (iii) the bond between the protein and the nucleotide was hydrolyzed by HgCl2, but was resistant to hydroxylamine. The 36 kDa protein reacted on Western blots with two different monoclonal antibodies (MAbs) against glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and was immunoprecipitated by both MAbs.