Precise spatial positioning of chromosomes during prometaphase: evidence for chromosomal order

The relative locations of several chromosomes within wheel-shaped prometaphase chromosome rosettes of human fibroblasts and HeLa cells were determined with fluorescence hybridization. Homologs were consistently positioned on opposite sides of the rosette, which suggests that chromosomes are separated into two haploid sets, each derived from one parent. The relative locations of chromosomes on the rosette were mapped by dual hybridizations. The data suggest that the chromosome orders within the two haploid sets are antiparallel. This chromosome arrangement in human cells appears to be both independent of cell type- and species-specific and may influence chromosome topology throughout the cell cycle.     

Effects of spatial cuing on luminance detectability: Psychophysical and electrophysiological evidence for early selection.

Three experiments were conducted to determine whether attention-related changes in luminance detectability reflect a modulation of early sensory processing. Exps 1 and 2 used peripheral cues to direct attention and found substantial effects of cue validity on target detectability; these effects were consistent with a sensory-level locus of selection but not with certain memory- or decision-level mechanisms. In Exp 3, event-related brain potentials were recorded in a similar paradigm using central cues, and attention was found to produce changes in sensory-evoked brain activity beginning within the 1st 1 msec of stimulus processing. These changes included both an enhancement of sensory responses to attended stimuli and a suppression of sensory responses to unattended stimuli; the enhancement and suppression effects were isolated to different neural responses, indicating that they may arise from independent attentional mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Item and order information in spatial memory.

14 male Holtzman albino rats were taught to perform order and item discriminations in an 8-arm radial maze. In Exp I, 2 groups of Ss learned different order discriminations with reward contingent on repeating or avoiding the most recently visited of 2 locations. Each trial began with a random order of 8 forced choices and ended with a choice between the 1st and 7th arms. Rate of learning depended on the compatibility of reward contingencies and preexperimental response biases. In Exp II, each trial began with a list of 7 forced choices and ended in a choice between either the 1st or 6th arm and the arm not presented; accuracy of performing these item discriminations depended on both serial position and the response tendencies acquired in Exp I. In Exp III, a 1-hr postlist delay impaired the order discrimination more than the item discrimination, and the effects of intertrial interval depended on previously acquired response biases. Results are discussed in terms of a 2-stage model that segregates a single memory process from decision/response processes. Item and order discriminations do not appear to be based on separate sources of information and do not appear to require fundamentally different memory processes. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multifocal renal cell carcinoma: evidence for a common clonal origin

The reported incidence of satellite tumor lesions in kidneys resected by radical nephrectomy for renal cell carcinoma (RCC) is 7-25%; however, genetic analyses of satellite tumors in comparison with those of main tumor lesions have not been performed well. In the present study, we investigated the incidence of loss of heterozygosity (LOH) at chromosome arms 3p, 6q, 8p, 9p, 9q, and 14q using 18 microsatellite markers in 10 nonpapillary RCCs of 50 mm or less in diameter and the accompanying satellite tumor lesions to evaluate the genetic alterations in main and satellite tumors. LOH was detected in 10, 3, 5, 3, 2, and 3 cases at chromosome arms 3p, 6q, 8p, 9p, 9q, and 14q, respectively. In addition, primary and satellite tumor lesions in 8 of 10 cases exhibited identical patterns of LOH on the 18 loci examined. In the remaining two cases, both main and satellite tumors demonstrated LOH on the common seven and three loci, respectively, whereas for another locus, LOH was observed only in the satellite tumor lesions. The similarity of LOH patterns detected in main and satellite tumor lesions indicates that the presence of satellite tumors might be the result of intrarenal metastasis from the main tumor lesion. These findings strongly suggest that even in case of small nonpapillary RCC, nephron-sparing surgery might carry the risk of failing to prevent postoperative local recurrence due to the incomplete resection of unrecognized satellite tumors with genetic alterations similar to those of the main tumor.     

Temporal and spatial characteristics of intracerebral seizure propagation: predictive value in surgery for temporal lobe epilepsy

We examined the prognostic value of spatial and temporal characteristics of intracerebral propagation of seizures during temporal lobe epilepsy (TLE) surgery. Seven TLE patients resistant to standard anterotemporal lobectomy who had no known causes of resistance [e.g., extratemporal (ET), lesions, multifocal epilepsy] were matched with 7 seizure-free patients and 7 others who were almost seizure-free after operation. Intracerebral ictal propagation pathways were not different in the three groups. Propagation was multidirectional, most frequently to the frontal lobes and sometimes to the contralateral temporal lobe (CTL). ET propagation delays were significantly shorter in resistant patients than in markedly improved patients. The resistant group also had more frequent propagation delays < 1.0 s, but propagation times > 1.0 s were equally likely in all groups. The extent of ET propagation and frequency of focal onsets were not different among the groups. Results suggest that very short propagation times predict reduced efficacy of operation, and that long propagation times are not related to surgical success.     

Further evidence for hierarchical chunking in rat spatial memory.

In Experiment 1, rats were given a test to determine the order of preference among 3 types of food. Two groups of rats then were trained on a 12-arm radial maze in Experiment 2, with the 3 foods placed in fixed-arm locations for 1 group and in locations that varied randomly across sessions for the other group. The results replicated those of Dallal and Meck (1990) by showing faster learning and more clustering of arm choices by food type in the fixed locations group than in the random-locations group. Two further experiments were performed to test the chunking hypothesis. Observations of working memory in Experiment 3 and the reorganization of reference memory in Experiment 4 both supported the chunking hypothesis by showing superior spatial memory and arm chunking by food type when chunk integrity was maintained than when it was compromised. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tumor-associated cysteine proteinase activities in human melanoma cells and fibroblasts of different origin

Specific catalytic activities of cysteine proteinases including cathepsins B (EC 3.4.22.1) and L (EC 3.4.22.15) in human melanoma cell lines SK-MEL-28, SK-MEL-30, MEL-HO and in fibroblasts of different origin are reported. Cell line-specific pH profiles of these cysteine proteinases were determined fluorometrically with benzyloxycarbonyl-phenylalanyl-arginine-amidomethylcoumarine (Z-Phe-Arg-AMC) under saturated conditions. Single activities of cathepsins B and L were inactivated by urea and by benzyloxycarbonyl-phenylalanyl-phenylalanine-diazomethylketone (Z-Phe-Phe-CHN2) in order to describe the activities of these enzymes separately. The melanoma cell line MEL-HO, which originated from a primary lesion, showed highest activity of an unknown cysteine proteinase. This enzyme is not inactivated by urea and Z-Phe-Phe-CHN2 and has a Michaelis constant (K(M) value) of approximately 1 mM. The specific characteristics suggest that it is a tumor-associated cathepsin B. In addition, high invasive subpopulations of SK-MEL-28 and SK-MEL-30 cell lines isolated by an invasion assay showed higher proteinase activities than the low invasive subpopulations. Furthermore, in fibroblasts originating from melanoma tissue cysteine proteinase activities were increased compared to normal skin fibroblasts. In conclusion, these results indicate that these cysteine proteinases shown here are tumor-associated proteinases, possibly facilitating invasion and dissemination of melanoma cells.     

Measurement of inhibin and activin in early human pregnancy: demonstration of fetoplacental origin and role in prediction of early-pregnancy outcome

To determine the source of the dimeric glycoproteins inhibin A (alpha-betaA) and activin A (betaA-betaA) in early pregnancy, we analyzed serial blood samples from women who became pregnant following in vitro fertilization (IVF) with fresh embryo transfer (ET; n = 52) and from women who achieved pregnancy with frozen-thawed embryos (n = 8). Elevated serum levels of inhibin A were detected in ongoing pregnancies from 4 wk gestation (13 days following ET) and increased to an initial peak at 9-10 wk gestation. Significantly higher levels (p < 0.05) were found in the multiple pregnancies, and nonviable clinical pregnancies had very low levels of inhibin A. Total activin A was detectable 14 days after ET (positive pregnancy test), and higher levels were associated with multiple gestations while rapidly falling levels heralded embryonic demise. The fetoplacental unit is thus confirmed as the major source of these glycoproteins. Inhibin pro-alphaC, which circulates in great excess as a functionally inactive monomer and as part of high molecular weight functional dimers, was detectable at levels above normal late-luteal values in singleton and multiple IVF arising from fresh ETs. With frozen-thawed embryo pregnancies, the levels of pro-alphaC-containing inhibins were extremely low, confirming that the corpus luteum of pregnancy is the major source of the alpha monomer. The initially low levels and very rapid decline in inhibin A in pregnancies with embryonic failure suggest a role for this glycoprotein as a monitor of early-pregnancy viability.     

Feeling-of-knowing in fact retrieval: further evidence for preservation in early Alzheimer's disease

The ability to retrieve and monitor factual information varying in datedness (i.e., dated vs. contemporary) was examined in healthy older adults and patients in an early phase of Alzheimer's disease (AD). Subjects were given free recall and multiple-choice recognition tests of 48 general knowledge questions. For all questions not responded to in recall, subjects made feeling-of-knowing (FOK) judgments. Results indicated dementia-related deficits in both recall and recognition, although both groups showed better recall and recognition with the dated compared with the contemporary questions. Importantly, despite deficits in fact retrieval, the AD patients showed intact monitoring of stored knowledge, as indicated by equivalent FOK accuracy for both groups. In addition, FOK accuracy was similar for the dated and the contemporary information in both groups, suggesting independence between level of general knowledge and the ability to supervise information stored in memory.     

Working memory in young children: evidence for modality-specificity and implications for cerebral reorganization in early childhood

Digit span (DS) and visual-spatial memory span (VMS) tasks have been considered indices of auditory and visual spatial processing, respectively, often classified as "primary memory" or "attention". There has been limited evidence for their modality specificity, however. We present two children who showed visual spatial processing deficiencies (including VMS) and non-dominant manual inefficiency with normal visual-spatial perception, auditory-verbal processing and dominant fine manual skills. These children support a distinction between auditory and visual-spatial memory span. These findings are discussed with regard to a hypothesis that the unique expression of VMS is time-limited, that visual-spatial processing becomes more verbalized as children learn to read and that these behavioral changes produce a lateral shift in cortical processing of visual spatial information.     

Cervical cancer and human papillomavirus: epidemiological evidence and perspectives for prevention

The ts1 Moloney murine leukemia virus causes a degenerative neurologic disease in mice characterized by the development of noninflammatory spongiform encephalomyelopathy. To determine whether gag and pol gene products and viral replication are necessary for the ts1-env gene product to cause neurodegeneration, we generated transgenic mice harboring only ts1-env. Neuropathological lesions were observed in mice expressing the transgene in the central nervous system. This implies that gag and pol gene products and viral replication are not necessary for ts1-env to cause a mild form of neurodegeneration in mice.     

Maturation promoting factor activation in early amphibian embryos: temporal and spatial control

The cytoplasmic localisation of factors capable of influencing the behaviour of nuclei has long been considered a potential mechanisms for generating cell differences during development. Yoshio Masui was instrumental in identifying two cytoplasmic factors, maturation promoting factor (MPF) and cytostatic factor (CSF), defining the first biological assay for their isolation and characterisation. These biological assays involved the transfer of cytoplasm between amphibian oocytes, MPF being able to promote meiotic maturation (progression to MII) and CSF to stabilise the MII state. Masui was subsequently involved in developing a 'cell-free' system with the potential for analysis not just of MPF and CSF, but many aspects of nucleo-cytoplasmic interaction. Masui and Markert initially showed that MPF activity could be generated in enucleate oocytes following progesterone stimulation, indicating a cytoplasmic origin. Masui subsequently showed that MPF activity was distributed unevenly through the egg of Rana pipiens during maturation. In this review we will consider the historical context in which the MPF assays were established, then briefly consider some of the molecular components that are now known to influence MPF activation. We will then consider evidence for the asymmetric activation of MPF and the possibility that the nucleus contributes to MPF activation in early embryos.     

Birth order and age differences in early sibling roles.

76 2-child families were assigned to 1 of 3 cohorts that differed in the 2nd-born's age at an initial home visit (5, 11, or 17 mo). The families were seen again 6 mo later. Children were rated by their mothers on 9 sibling role qualities and were videotaped interacting in structured situations. First- and 2nd-borns were seen to fulfill different roles, e.g. mothers rated 1st-borns lower than 2nd-borns on identification but higher on help. The differences between the 2 children on some aspects of sibling roles (e.g., identification) did not change with their ages. Yet other aspects (e.g., help) became increasingly similar, and such changes were attributable to the baby's development. Children's behavior in the structured situations also changed. Some changes were attributable to the baby growing older, whereas others were attributable to the older sibling's or to both children's development. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Revisiting evidence for modularity and functional equivalence across verbal and spatial domains in memory.

The authors revisited evidence in favor of modularity and of functional equivalence between the processing of verbal and spatial information in short-term memory. This was done by investigating the patterns of intrusions, omissions, transpositions, and fill-ins in verbal and spatial serial recall and order reconstruction tasks under control, articulatory suppression, and spatial tapping conditions. The authors observed that when tasks were fully equated, all patterns of errors were equivalent between the verbal and spatial domains. Moreover, articulatory suppression interfered more with the verbal memory tasks than with the spatial memory tasks. This interference was mostly due to an increase of omissions and transpositions. Similarly, tapping was more disruptive of spatial memory than of verbal memory tasks and affected primarily the number of omissions and transpositions. The patterns of errors and their interaction with interference are discussed in light of the predominant approaches to modeling memory and provide a rich set of data for modeling efforts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Myeloma bone marrow plasma cells: evidence for their capacity as antigen-presenting cells

Myeloma plasma cells constitute 10% to 90% of the total bone marrow cell count in patients with multiple myeloma (MM). These cells express a variety of cell surface markers, such as HLA-ABC and HLA-DR, and surface antigens that are necessary for professional antigen-presenting cells, including adhesion and costimulatory molecules. In this study, we examined the expression of major histocompatability complex (MHC) and costimulatory molecules on CD38(bright,++) plasma cells in bone marrow aspirates from eight MM patients. Small percentages of plasma cells expressed weak but detectable levels of HLA-DR, HLA-DQ, CD40, CD80, and CD86, which could be upregulated by interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha. CD38++ plasma cell and CD38(dim,+) cells were sorted from freshly isolated bone marrow mononuclear cells and tested for their capacity to act as antigen-presenting cells. Indeed, both CD38++ plasma cells and CD38+ cells were able to stimulate allogeneic T cells and present the soluble antigens purified protein derivative and tetanus toxoid to autologous T cells. Recognition of the antigens led to T-cell proliferation and secretion of IFN-gamma and was MHC class-I and -II restricted. Antigen processing and presentation by CD38++ and CD38+ cells were abolished by treatment of the cells with chloroquine. Hence, our study provides for the first time evidence that myeloma plasma cells may act as antigen-presenting cells. Further studies are warranted to examine in detail the molecules required for inducing T-cell stimulation.     

Fatigue crack initiation and early propagation in Al 2219-T851

Fatigue crack initiation in Al 2219-T851 for fully reversed loading(R = σ/σ_max =?1) parallel to the material rolling direction is found to occur at intermetallic inclusions at the specimen surface. The inclusions are not involved in crack initiation for fatigue perpendicular to the rolling direction, and for this orientation crack initiation is at grain boundaries and specimens have an increased fatigue life. Except for fatigue at low peak stress, multiple numbers of microcracks are formed and for selected failed specimens the number of cracks has been determined as a function of crack length. Such crack length distribution measurements show that there is significant retardation of microcracks by interaction with grain boundaries. Furthermore it is found that the coalescence of microcracks provides a mechanism for cracking to “jump“ grain boundaries and reduce fatigue lifetime. The effect of relative humidity on this process is to increase the observed mean crack length, and decrease the number of crack initiations apparently due to weakening of the matrix-intermetallic interface at potential initiation sites. The overall result is that no significant dependence of fatigue life on relative humidity is found.