Trypanosoma cruzi: chemotherapy with benznidazole in mice inoculated with strains from Paraná state and from different endemic areas of Brazil

Segments of the tibial diaphysis from 24 adult dogs were reimplanted after extracorporeal autoclaving or gamma-irradiation. Fixation was by interlocking intramedullary nailing, or plating. The dogs were killed after 36 weeks and the tibias examined. Bony union was seen in 46 of the 48 contact areas. Microangiography and Tc-perfusion scans demonstrated complete revascularisation of all the grafts. Biomechanical tests showed defective union with increased bending and decreased stiffness compared to normal controls. Fluorescent microscopy confirmed restitution of Haversian systems and slow replacement of the graft by lamellar bone containing viable osteocytes.     

Trypanosoma cruzi infection in mice enhances the membrane expression of low-affinity Fc receptors for IgG and the release of their soluble forms

The membrane expression of low-affinity Fc receptors for IgG (Fc gamma RII/III) on cells and the number of Fc gamma RII/III(+) cells were studied by flow cytometry, using the 2.4G2 MoAb, in mice infected by Trypanosoma cruzi. Cells from spleen, mesenteric lymph nodes and peritoneum were collected on days 10, 20, 30 and 40 post infection (p.i.). The in vivo serum level of soluble Fc gamma RII/III, as well as its in vitro release by cells from infected mice were studied. Parasitaemia and IgG1, IgG2a and IgG2b T. cruzi-specific antibody titres were also recorded. Both the expression of Fc gamma R on cell membrane and the absolute number of Fc gamma R(+) cells increased in spleen and in mesenteric lymph nodes, but not in peritoneum. The modifications in spleen occurred in the early and late parasitaemic phase of infection, i.e., before and after detection of T. cruzi-specific antibodies (from day 10 to 40 p.i.). In mesenteric lymph nodes, the variations were observed only in the early acute infection, when antibodies were not yet detectable at significant levels (on days 10 and 20 p.i.). Higher levels of soluble Fc gamma R were detected in sera and in culture supernatants of spleen and lymph node cells from day 20 to 40 p.i. These results show that T. cruzi infection in mice upregulates the expression and the release of Fc gamma RII/III, in the acute phase of infection, before as well as after the rise of antibody response.     

Individual differences in the selection and use of features for classifying visual stimuli

Two experiments were performed to investigate the classification of pot-like outlines by human judges. In experiment 1, seventy-two pot-like shapes, drawn by using all possible combinations of values of four pot ratios, were classified by twenty subjects and by a computer program. The shapes varied only in quantitative features and possessed no all-or-none characteristics. In experiment 2,256 shapes traced from drawings of existing pots were classified by fifteen judges. The pots varied in both quantitative and all-or-none features. The results showed that there were differences between judges in the weightings they assigned to different features, and the judges themselves could be classified according to the weightings they gave the features. There were even differences in the way different judges used all-or-none features for classifying. Possible mechanisms are suggested for the basis of these differences.     

Regional differences in cerebral noradrenaline turnover in mice withdrawn from repeated morphine treatment and tolerance to the effects of acute morphine

The effects of morphine withdrawal and challenge doses (10 or 30 mg/kg) on the alpha-methyl-p-tyrosine (alpha MT)-induced noradrenaline (NA) depletion as well as on the free 3-methoxy-4-hydroxyphenylethylene glycol (MOPEG) concentration were studied in various brain areas of NMRI mice. Morphine was given subcutaneously 3 times daily for 5 days followed by 1 or 3 days' withdrawal. In morphine withdrawn mice the alpha MT-induced NA depletion and the free MOPEG concentrations were differentially altered. At 1-day withdrawal the alpha MT-induced NA depletion was retarded and the NA concentration was elevated in the forebrain area indicating reduced release of NA. Simultaneously, however, the free MOPEG concentration was significantly elevated in the forebrain area and in the lower brain stem suggesting enhanced NA turnover. No withdrawal-induced changes were found in the hypothalamic NA turnover. Acute morphine elevated the free MOPEG concentration and accelerated the alpha MT-induced NA depletion in all brain areas of control mice but not in mice withdrawn for 1 day from repeated morphine treatment. At 3 days' withdrawal, however, the 30 mg/kg morphine dose slightly accelerated the NA depletion in the forebrain area. These results show that morphine withdrawal differentially alters the alpha MT-induced NA depletion and the free MOPEG concentration in various mouse brain areas. These effects are relatively modest suggesting that in mice the noradrenergic mechanisms play a minor role in morphine withdrawal syndrome. However, in all brain areas of the morphine-withdrawn mice tolerance was found towards the NA turnover and release accelerating effect of acute morphine.     

Octa-alkyl zinc phthalocyanines: potential photosensitizers for use in the photodynamic therapy of cancer

The synthesis, characterization and electronic spectra of a series of nine 1,4,8,11,15,18,22,25-octa-alkyl zinc phthalocyanines (ZnPc), potential photosensitizers for the photodynamic therapy of cancer, are described. The substituents on the phthalocyanine (Pc) macrocycle "red-shift" the absorbance maximum, in cyclohexane, of all nine members of this series to a value of 703 +/- 2 nm, with a corrected fluorescence emission maximum for the octadecyl derivative of 715 nm. The solubilities and degree of aggregation of six examples in cyclohexane have been measured. The highest homologue, the octadecyl derivative, remains essentially unaggregated to a concentration of 1.5 x 10(-4) mol dm-3. the photostability of this Pc has been examined and the compound shown to be sensitive to photooxidation processes which lead to its decomposition to 3,6-bis-decylphthalimide. Known singlet oxygen quenchers inhibit the photodecomposition. In a comparative study, the octadecyl ZnPc underwent a more rapid photodecomposition than the corresponding metal-free derivative.     

The structure of autobiographical memory and the event history calendar: potential improvements in the quality of retrospective reports in surveys

This paper reviews the literature on the structure of autobiographical memory and points to the use of event history calendars as a survey methodology that reflects this structure. Autobiographical memory structure is characterised as an hierarchical network that includes extended, summarised, and specific events, and that permits retrieval of past events through multiple pathways that work top-down in the hierarchy, sequentially within life themes that unify extended events, and in parallel across life themes that involve contemporaneous and sequential events. Traditional survey questions tend to segment related aspects of autobiographical events from one another, and do not reflect the interrelatedness of events as indicated within the structure of autobiographical memory. In contrast, event history calendars do promote sequential and parallel retrieval within the autobiographical memory network. By reflecting the structure of autobiographical memory, the use of event history calenders has considerable potential in assisting respondents to reconstruct their personal pasts more completely and accurately, maximising the quality of retrospective reports.     

A 2.8 A resolution structure of 6-phosphogluconate dehydrogenase from the protozoan parasite Trypanosoma brucei: comparison with the sheep enzyme accounts for differences in activity with coenzyme and substrate analogues

The three-dimensional structure of 6-phosphogluconate dehydrogenase (6PGDH) from the parasitic protozoan Trypanosoma brucei has been solved at 2.8 A resolution. This pentose phosphate pathway enzyme is NADP-dependent; NADPH generated in the reaction protects against oxidative stress. The enzyme crystallises in the space-group P3121 with a dimer in the asymmetric unit and cell dimensions a=b=135.13 A, c=116.74 A, alpha=beta=90 degrees, gamma=120 degrees. The structure has refined to R=18.6% (Rfree=27.3%) with good geometry. The amino acid sequence of T. brucei 6PGDH is only 35% identical to that of the sheep liver enzyme and significant activity differences have been observed. The active dimer assembles with the C-terminal tail of one subunit threaded through the other, forming part of the substrate binding site. The tail of T. brucei 6PGDH is shorter than that of the sheep enzyme and its terminal residues associate tightly with the second monomer. The three-dimensional structure shows this generates additional interactions between the subunits close to the active site; the coenzyme binding domain is thereby associated more tightly with the helical domain. Three residues, conserved in all other known sequences, are important in creating a salt bridge between monomers close to the substrate binding site. The differences could explain the 200-fold enhanced affinity observed for the substrate analogue 6-phospho-2-deoxy-D-gluconate and suggest targets for anti-parasite drug design. The coenzyme binding domain of 6PGDH has a beta-alpha-beta fold; while in most species the "fingerprint" sequence is GxAxxG, in the T. brucei enzyme it is GxGxxG. Additional interactions between the enzyme and the coenzyme bis-phosphate are likely in the parasite 6PGDH, accounting for greater inhibition (40-fold) of 2'5'-ADP. While the core of the T. brucei dimer was restrained during refinement, several conformational differences have been found between the monomers; those at the coenzyme binding site suggest the molecule could be asymmetric during the enzyme reaction.     

Evaluation of plasmid DNA for in vivo gene therapy: factors affecting the number of transfected fibers

Gene transfer by intramuscular injection of plasmid DNA has potential application in gene therapy. We examined factors affecting the number of expressing fibers, in contrast to total expression, following injection of plasmid DNA. Barium chloride proved effective in inducing muscle necrosis and regeneration in mice, and this increased the number of fibers expressing a reporter gene. Coinjection of ion-channel modulators did not increase the number of positive fibers, but increasing dose and repeated administration of plasmid did. Importantly, the plasmid size (7-16 kb) did not affect the number of fibers expressing the transgene, in both normal and regenerating muscle.     

Developmental differences in organization and recall: Training in the use of organizational techniques.

Used an alternating sort-recall procedure in 3 experiments to train 204 elementary school children in the use of organizational techniques as memory aids. All Ss sorted a group of words into 2–7 categories, and some Ss were required to learn the sorting patterns generated by adults. In Exp I, the semantic sophistication of a S's sorting style predicted recall performance. Further, the tendency to improve memory performance as a result of being constrained to adult sorting patterns varied with age; constrained 5th graders significantly improved their recall, whereas the recall of 3rd and 7th grade Ss was not affected by this training. However, more detailed organizational training in Exp II facilitated the recall of 3rd graders. In Exp II, it was found that the constraining procedure was not necessary for facilitation to be observed. Rather, instructions to group words on the basis of meaning were sufficient to produce improved recall. Further, improvements in sorting style accompanied all significant changes in recall. Findings are discussed in terms of a discrepancy between the information which a child has in permanent memory and that which he uses spontaneously in the context of a memorization task. The importance of input organization as a mediating factor in memory performance and development is suggested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dietary patterns associated with a low-fat diet in the national health examination follow-up study: identification of potential confounders for epidemiologic analyses

To identify systematically the nutrient and food group intakes associated with a low-fat diet, the authors used the detailed dietary information collected from 10,306 individuals aged 32-86 years in the 1982-1984 National Health Epidemiologic Follow-up Study. Intakes of vitamin C and percentages of calories from carbohydrates, dietary fiber, poultry, low-fat dairy products, fruits, vegetables, cereals, and whole grains were markedly higher, while intakes of protein, total fat, saturated fat, oleic and linoleic acids, cholesterol, sodium, all red meats, high-fat dairy products, eggs, nuts, white bread, fried potatoes, desserts, fats, and oils were much lower in the quartile with the lowest percentage of calories from fat. These dietary patterns associated with a low-fat diet were essentially constant across strata of age, sex, race, and socioeconomic status. This study suggests that individuals on a low-fat diet substitute certain carbohydrate-rich foods such as fruits and vegetables for fat. Given these associations between low-fat diets and other dietary factors independently associated with certain cancers, these dietary factors should be considered potential confounders in studies of dietary fat and these cancers.     

Morphologic diversity in malignant melanoma: the potential use of microdissection and the polymerase chain reaction for diagnosis

Malignant melanoma (MM) can mimic soft tissue (ST) and epithelial neoplasms. An immunoperoxidase (IP) panel and a morphologic comparison of the primary are used in diagnosis, which can be difficult when the morphologic and IP profiles of a metastatic lesion simulate those of an ST neoplasm. Through the comparison of known genetic abnormalities in primary and metastatic neoplasms, a definitive diagnosis can be suggested on the basis of the finding of identical allelic losses through the use of microdissection (MD) and the polymerase chain reaction (PCR). Genetic alterations involving the p16 gene on chromosome 9p21 have been observed in MM. We present the case of a 56-year-old man with known MM in whom multiple metastatic lesions to the skin and an adrenal gland developed during a 5-year period. A fine-needle aspiration (FNA) of a new ST buttock lesion was performed; the specimen had cytologic features different from those of the primary neoplasm and simulated a possible primary ST neoplasm. We attempted to make a definitive diagnosis of MM in the FNA of the ST buttock lesion through a genetic comparison with the primary neoplasm as well as with the other metastatic sites. Direct-visualization MD was performed on histologic glass slides of the primary and adjacent tissue (normal control), and the metastatic lesions, along with malignant cell clusters from the buttock lesion FNA. DNA was extracted and PCR amplified with primers D9S171 and IFNA for the p16 locus at the 9p21-22 region. Loss of heterozygosity for the D9S171 marker at the p16 gene locus was identified in all of the neoplastic tissue tested. Normal skin elements did not show deletion. The combination of MD and PCR are powerful tools that can be used for the comparison of genetic abnormalities in primary and metastatic neoplasms with unusual morphologic features to help support a diagnosis with a noncontributory IP.     

Cognitive motivations for drug use among adolescents: Longitudinal tests of gender differences and predictors of change in drug use.

Four factors were found to reflect 15 reasons for drug use, Enhance Positive Affect and Creativity, Reduce Negative Affect, Social Cohesion, and Addiction. These factors were found to reflect second-order latent factors of Alcohol Motivations as well as Cannabis Motivations and to be invariant by sex. All Alcohol and Cannabis Motivation scales were significantly correlated with actual use of alcohol, cannabis, cocaine, and hard drugs. In both bivariate and latent variable longitudinal analyses over a 1-yr period, motivations for alcohol use increased actual use of alcohol, whereas motivations for cannabis use increased all types of drug use. Very similar patterns of effects were noted for boys and girls. We conclude that self-acknowledged cognitive motivations or reasons for drug use are important etiological factors in understanding actual drug-use behavior and discuss the counseling and prevention implications of these results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Risk assessment on the carcinogenic potential of hybridoma cell DNA: implications for residual contaminating cellular DNA in biological products

Fifty people (25 at risk for an eating disorder, 25 controls) performed a simple reaction-time (SRT) task and a negative-priming (NP) task. The two groups did not differ on the SRT task. For the NP task, the controls displayed the NP effect (responses on critical trials were slower than responses on control trials). At-risk participants, however, revealed no such NP effect. Although the pattern of NP performance in the at-risk participants may indicate that they as a group had deficiencies in their ability to inhibit irrelevant information, it is also possible that issues related to obsessionality, perfectionism, and restraint in the at-risk group affected the results.     

A new AluI satellite DNA in the root-knot nematode Meloidogyne fallax: relationships with satellites from the sympatric species M. hapla and M. chitwoodi

A highly abundant satellite DNA comprising 20% of the Meloidogyne fallax (Nematoda, Tylenchida) genome was cloned and sequenced. The satellite monomer is 173 bp long and has a high A + T content of 72.3%, with frequent runs of A's and T's. The sequence variability of the monomers is 2.7%, mainly due to random distribution of single-point mutations. A search for evidence of internal repeated subunits in the monomer sequence revealed a 6-bp motif (AAATTT) for which five degenerated repeats, differing by just a single base pair, could be identified. Pairwise comparison of the M. fallax satellite with those from the sympatric species Meloidogyne chitwoodi and Meloidogyne hapla revealed a high sequence similarity (68.39%) with one satellite DNA subfamily in M. chitwoodi, which indicated an unexpected close relationship between them. Given the high copy number and the extreme sequence homogeneity among monomeric units, it may be assumed that the satellite DNA of M. fallax could have evolved through some recent and extensive amplification burst in the nematode genome. In this case, its relatively short life would not yet have allowed the accumulation of random mutations in independent amplified repeats. Considering the morphological resemblance between the two species and their ability to produce interspecific fertile hybrids under controlled conditions, these results indicate that M. fallax may share a common ancestor with M. chitwoodi, from which it could have diverged recently. All these data suggest that M. fallax could be the result of a recent speciation process and show that Meloidogyne satellite DNAs may be of interest to resolve phylogenetic relationships among closely related species from this genus.     

Lexical memory in poor and normal readers: Developmental differences in the use of category cues.

Examined whether differences between poor and normal reading children on lexical memory tasks may be attributed to semantic development, using 80 2nd and 6th graders. Ss were presented with 4 lists of taxonomic categories and were asked to recall items under (a) noncued and random conditions, with Ss instructed to recall as many items as possible and (b) cued and blocked conditions, with Ss told to recall items in a category. All Ss performed better with category cues. Group differences on category recall were more reliable at Grade 6, suggesting that facility in accessing taxonomic categories may differentiate poor and normal readers more reliably at older age levels. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in skilled reaching for food related to increased number of gestures: Evidence for goal and habit learning of skilled reaching.

Skilled reaching in rodents and primate is motorically similar, but success in reaching by rodents is distinctively variable. The source of this variability has not been examined previously. Long–Evans rats were videotaped as they reached for food in 2 different reaching tasks, and endpoint measures of performance were examined in relation to variables previously associated with individual differences, including testing procedures, rehabilitation, movement ability, general locomotor activity, and cortical anatomy. There were individual differences in performance, but these were not related to the dependent measures related to training, movement ability, locomotor activity, or anatomy (e.g., brain with cortical thickness, acetylcholinesterase and neuron density, pyramidal tract size). Success was negatively related to numbers of gestures (non–weight-bearing movements of the reaching limb) used on a reach, however. The results are discussed in relation to the idea that individual differences in response strategy bias some rats to use a more successful goal strategy and others to use a less successful habit strategy for skilled reaching. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in the use of demand and withdraw behavior in marriage: Examining the social structure hypothesis.

Studies consistently show sex differences in married couples' use of demand and withdraw behavior. The social structure hypothesis proposes that these differences are the result of power differentials between spouses. This study examined the link between 3 aspects of marital power and demanding and withdrawal behavior. Contrary to social structure predictions, results showed that wives did not possess less decision-making ability or access to resources and appeared to exhibit greater situational power (i.e., domineering and dominant behaviors) than did their husbands during problem-solving discussions. Furthermore, the spouse who exhibited the most demands also exhibited the most domineering and dominant behaviors, whereas the spouse who exhibited the most withdrawal exhibited the least domineering and dominant behaviors during problem-solving discussions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)