Understanding the structure of autobiographical memories: A study of trauma memories from the 1994 Rwandan genocide

How do we remember traumatic events, and are these memories different in individuals who experience post-traumatic stress? Some evidence suggests that traumatic events are mnemonically enhanced, or include more episodic detail, relative to other types of memories. Simultaneously, individuals with post-traumatic stress disorder (PTSD) have more non-episodic details in all of their memories, a pattern hypothesized to result from impairment in executive function. Here, we explore these questions in a unique population that experienced severely traumatic events more than 20 years ago - individuals who lived through the 1994 genocide in Rwanda. Participants recalled events from the genocide, negative events unrelated to the genocide, neutral events, and positive events. We used the Autobiographical Interview method to label memory details as episodic or non-episodic. We found that memories from the genocide showed robust mnemonic enhancement, with more episodic than non-episodic details, and contained more details overall than any other memory type. This pattern was not impacted by post-traumatic stress. Overall, this study provides evidence that traumatic events create vivid long-lasting episodic memories, in this case even more than 20 years later.

Hippocampus long-axis specialization throughout development: A meta-analysis

The human adult hippocampus can be subdivided into the head, or anterior hippocampus and its body and tail, or posterior hippocampus, and a wealth of functional differences along the longitudinal axis have been reported. One line of literature emphasizes specialization for different aspects of cognition, whereas another emphasizes the unique role of the anterior hippocampus in emotional processing. While some research suggests that functional differences in memory between the anterior and posterior hippocampus appear early in development, it remains unclear whether this is also the case for functional differences in emotion processing. The goal of this meta-analysis was to determine whether the long-axis functional specialization observed in adults is present earlier in development. Using a quantitative meta-analysis, long-axis functional specialization was assessed using the data from 26 functional magnetic resonance imaging studies, which included 39 contrasts and 804 participants ranging in age from 4 to 21 years. Results indicated that emotion was more strongly localized to the anterior hippocampus, with memory being more strongly localized to the posterior hippocampus, demonstrating long-axis specialization with regard to memory and emotion in children similar to that seen in adults. An additional analysis of laterality indicated that while memory was left dominant, emotion was processed bilaterally.

Activity in perirhinal and entorhinal cortex predicts perceived visual similarities among category exemplars with highest precision

Vision neuroscience has made great strides in understanding the hierarchical organization of object representations along the ventral visual stream (VVS). How VVS representations capture fine-grained visual similarities between objects that observers subjectively perceive has received limited examination so far. In the current study, we addressed this question by focussing on perceived visual similarities among subordinate exemplars of real-world categories. We hypothesized that these perceived similarities are reflected with highest fidelity in neural activity patterns downstream from inferotemporal regions, namely in perirhinal (PrC) and anterolateral entorhinal cortex (alErC) in the medial temporal lobe. To address this issue with functional magnetic resonance imaging (fMRI), we administered a modified 1-back task that required discrimination between category exemplars as well as categorization. Further, we obtained observer-specific ratings of perceived visual similarities, which predicted behavioural discrimination performance during scanning. As anticipated, we found that activity patterns in PrC and alErC predicted the structure of perceived visual similarity relationships among category exemplars, including its observer-specific component, with higher precision than any other VVS region. Our findings provide new evidence that subjective aspects of object perception that rely on fine-grained visual differentiation are reflected with highest fidelity in the medial temporal lobe.

Germline variants and phenotypic spectrum in a Canadian cohort of individuals with diffuse gastric cancer

Background

CDH1 pathogenic variants (pvs) cause most cases of inherited diffuse gastric cancer (dgc), but have low detection rates and vary geographically. In the present study, we examined hereditary causes of dgc in patients in Ontario.

Methods

CDH1 testing through single-site or multi-gene panels was conducted for patients with dgc meeting the 2015 International Gastric Cancer Linkage Consortium (igclc) criteria, or with isolated dgc at less than 50 years of age, or with a strong family history of cancer identified at the Zane Cohen Centre (zcc). All CDH1-positive patients at zcc, regardless of cancer history, were summarized.

Results

In 15 of 85 patients with dgc (17.6%), a pv or likely pv was identified through CDH1 single-site (n = 43) or multi-gene panel (n = 42) testing. The detection rate was 9.4% overall (8 of 85) and 11% using igclc criteria (7 of 65). No CDH1 pvs were identified in patients with isolated dgc at less than 40 years of age, but 1 pv was identified in a patient with isolated dgc at less than 50 years of age. Multi-gene panels identified 9 pvs (21.4%), including CDH1, STK11, ATM, BRCA2, MLH1, and MSH2. Review of 81 CDH1 carriers identified 10% with dgc (median age: 48 years; range: 38-59 years); 41% were unaffected (median age: 53 years; range: 26-89 years). Observed malignancies other than dgc or lobular breast cancer (lbc) included colorectal, gynecologic, kidney or bladder, prostate, testicular, and ductal breast cancers. Lobular-breast cancer was seen only in 3 families.

Conclusions

In Ontario, the detection rate of CDH1 pvs in patients with dgc was low: no pvs were identified in patients with isolated dgc at less than 40 years of age, and 1 was identified in a patient with isolated dgc at less than 50 years of age. Isolated lbc with no dgc was observed in CDH1-positive families, as were pathology-confirmed nondgc or non-lbc malignancies, which had not previously been reported. Given a phenotype that overlaps with other hereditary conditions, multi-gene panels are recommended for all patients with dgc at less than 50 years of age and for those meeting igclc criteria.

Animacy and real-world size shape object representations in the human medial temporal lobes

Identifying what an object is, and whether an object has been encountered before, is a crucial aspect of human behavior. Despite this importance, we do not yet have a complete understanding of the neural basis of these abilities. Investigations into the neural organization of human object representations have revealed category specific organization in the ventral visual stream in perceptual tasks. Interestingly, these categories fall within broader domains of organization, with reported distinctions between animate, inanimate large, and inanimate small objects. While there is some evidence for category specific effects in the medial temporal lobe (MTL), in particular in perirhinal and parahippocampal cortex, it is currently unclear whether domain level organization is also present across these structures. To this end, we used fMRI with a continuous recognition memory task. Stimuli were images of objects from several different categories, which were either animate or inanimate, or large or small within the inanimate domain. We employed representational similarity analysis (RSA) to test the hypothesis that object-evoked responses in MTL structures during recognition-memory judgments also show evidence for domain-level organization along both dimensions. Our data support this hypothesis. Specifically, object representations were shaped by either animacy, real-world size, or both, in perirhinal and parahippocampal cortex, and the hippocampus. While sensitivity to these dimensions differed across structures when probed individually, hinting at interesting links to functional differentiation, similarities in organization across MTL structures were more prominent overall. These results argue for continuity in the organization of object representations in the ventral visual stream and the MTL.

The duality of macrophage function in chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is the most common adult leukaemia and, in some patients, is accompanied by resistance to both chemotherapeutics and immunotherapeutics. In this review we will discuss the role of tumour associated macrophages (TAMs) in promoting CLL cell survival and resistance to immunotherapeutics. In addition, we will discuss mechanisms by which TAMs suppress T-cell mediated antitumour responses. Thus, targeting macrophages could be used to i) reduce the leukaemic burden via the induction of T-cell-mediated antitumour responses, ii) to reduce pro-survival signalling and enhance response to conventional chemotherapeutics or iii) enhance the response to therapeutic antibodies in current clinical use.

Multiple neural representations of elementary logical connectives

A defining trait of human cognition is the capacity to form compounds out of simple thoughts. This ability relies on the logical connectives AND, OR and IF. Simple propositions, e.g., 'There is a fork' and 'There is a knife', can be combined in alternative ways using logical connectives: e.g., 'There is a fork AND there is a knife', 'There is a fork OR there is a knife', 'IF there is a fork, there is a knife'. How does the brain represent compounds based on different logical connectives, and how are compounds evaluated in relation to new facts? In the present study, participants had to maintain and evaluate conjunctive (AND), disjunctive (OR) or conditional (IF) compounds while undergoing functional MRI. Our results suggest that, during maintenance, the left posterior inferior frontal gyrus (pIFG, BA44, or Broca's area) represents the surface form of compounds. During evaluation, the left pIFG switches to processing the full logical meaning of compounds, and two additional areas are recruited: the left anterior inferior frontal gyrus (aIFG, BA47) and the left intraparietal sulcus (IPS, BA40). The aIFG shows a pattern of activation similar to pIFG, and compatible with processing the full logical meaning of compounds, whereas activations in IPS differ with alternative interpretations of conditionals: logical vs conjunctive. These results uncover the functions of a basic cortical network underlying human compositional thought, and provide a shared neural foundation for the cognitive science of language and reasoning.

Mechanical stress enhances CD9 expression in cultured podocytes

Elevated glomerular pressure represents a high risk for the development of severe kidney diseases and causes an increase in mechanical load to podocytes. In this study, we investigated whether mechanical stress alters gene expression in cultured podocytes using gene arrays. We found that tetraspanin CD9 is significantly upregulated in cultured podocytes after mechanical stress. The differential expression of CD9 was confirmed by RT-PCR and Western blotting under stretched and unstretched conditions. Furthermore, mechanical stress resulted in a relocalization of CD9. To get an insight into the functional role of CD9, podocytes were transfected with pEGFP-CD9. The expression of CD9 induced the formation of substratum-attached thin arborized protrusions. Ca(2+) depletion revealed that podocytes overexpressing CD9 possess altered adhesive properties in contrast to the control transfected cells. Finally, elevated CD9 expression increased migration of podocytes in a wound assay. In summary, our results suggest that upregulation of CD9 may play an important role in podocyte morphology, adhesion, and migration.

Detection of the 4977 bp deletion of mitochondrial DNA in different human blood cells

As recently reported, it is possible to detect and quantify the amount of the deleted human mitochondrial DNA (mtDNA) in whole blood, platelets and peripheral blood mononuclear cells using real-time PCR. The aim of this study was to identify the cell types in human blood carrying the 4977 bp deleted mtDNA and their accumulation with regard to donor age. Whole blood from 10 healthy donors (five individuals aged from 19 to 22 years, five aged from 57 to 61 years) was separated in various cell populations such as granulocytes, B cells/monocytes and T cells. Purity of the cell isolates was determined by flow cytometry. Total DNA was extracted and 250 ng DNA of each cell type was subjected to PCR using fluorescent-labelled primer pairs. The specific PCR product of the 4977 bp deletion was quantified using an automated detection system. The accumulation of the 4977 bp deletion was more pronounced in T lymphocytes and granulocytes in comparison to B lymphocytes/monocytes. The amount of the 4977 bp deletion in whole blood varied from 0 to 0.00018%, in T lymphocytes from 0.00009 to 0.00160%, in granulocytes from 0 to 0.00162% and in the B lymphocyte/monocyte fraction from 0 to 0.00025%. The higher amount of the deletion in T lymphocytes may be due to a subset of lymphocytes with a longer lifespan thus facilitating the accumulation of mitochondrial damage. The higher amount in granulocytes could have the explanation in the higher release of free radicals for prevention of infectious diseases, because free radicals are supposed to damage the macromolecules of this cell type. The 10 donors displayed differences in the pattern of the accumulation with regard to the different cell types, but no age-dependent accumulation was observed. Differences of the accumulation pattern may be due to actual individual living behaviour or environmental factors.

Functional significance of PMM2 mutations in mildly affected patients with congenital disorders of glycosylation Ia

PURPOSE

Congenital disorders of glycosylation (CDG) result from mutations in N-glycan biosynthesis. Mutations in phosphomannomutase (PMM2) cause CDG-Ia. Here, we report four clinically mild patients and their mutations in PMM2.

METHODS

Analysis of the PMM2 cDNA and gene revealed the mutations affecting the glycosylation efficiency.

RESULTS

The patients have 30% to 50% normal PMM activity in fibroblasts due to different mutations in PMM2, and we studied the effect of each mutation on the PMM activity in a Saccharomyces cerevisiae expression system.

CONCLUSIONS

Each patient carried a severe mutation that decreased the PMM activity to less than 10% as well as a relatively mild mutation. A new mutation, deletion of base 24, changed the reading frame. The C9Y, C241S, and L32R mutations showed 27% to 45% activity when expressed in the eukaryotic expression system, and the more severe D148N was shown to be thermolabile.

Mycobacteria-induced TNF-alpha and IL-10 formation by human macrophages is differentially regulated at the level of mitogen-activated protein kinase activity

The clinical course of mycobacterial infections is linked to the capacity of pathogenic strains to modulate the initial antimycobacterial response of the macrophage. To elucidate some of the mechanisms involved, we studied early signal transduction events leading to cytokine formation by human monocyte-derived macrophages (MDM) in response to clinical isolates of Mycobacterium avium. TNF-alpha production induced by M. avium was inhibited by anti-CD14 mAbs, but not by Abs against the macrophage mannose receptor. Analysis of mitogen-activated protein (MAP) kinase activation (extracellular signal-regulated kinase 1/2, p38, and c-Jun NH(2)-terminal kinase) showed a rapid phosphorylation of all three subfamilies in response to M. avium, which was inhibited by anti-CD14 Abs. Using highly specific inhibitors of p38 (SB203580) and MAP kinase kinase-1 (PD98059), we found that activation of the extracellular signal-regulated kinase pathway, but not of p38, was essential for the M. avium-induced TNF-alpha formation. In contrast, IL-10 production was abrogated by the p38 inhibitor, but not by the MAP kinase kinase-1 inhibitor. In conclusion, M. avium-induced secretion of TNF-alpha and IL-10 by human macrophages is differentially regulated at the level of MAP kinase activity.

Purification and Characterization of the Voltage-Dependent Anion-Selective Channel Protein from Wheat Mitochondrial Membranes

An approximately 29-kD protein was purified from the membrane fraction of wheat (Triticum aestivum cv Dganit) mitochondria by the utilization of standard liquid chromatography techniques. The protein, designated MmP29 for mitochondrial membrane protein having a molecular mass of approximately 29 kD, exhibited cationic properties in a buffering solution, adjusted to pH 7.5. This positive charge enabled its passage through a diethylaminoethyl column, without interaction with the positively charged matrix. Subsequently, this protein was separated from the remaining polypeptides by a preferential elution from a hydroxylapatite/celite mixed column. Reconstituted liposomes containing this protein were characterized as being permeable to 8-amino-naphthalene 1,3,6-trisulfonic acid disodium salt (Mr 445) but non-permeable to dextran fluorescein (Mr 40,000). Additionally, MmP29 was inserted into planar phospholipid membranes, and anion-selective, voltage-dependent channels were demonstrated. All of the MmP29 properties mentioned highly resemble voltagedependent, anion-selective channel (VDAC) proteins, suggesting that MmP29 is the mitochondrial outer membrane VDAC protein of wheat.

Improvement of plant regeneration and GUS expression in scutellar wheat calli by optimization of culture conditions and DNA-microprojectile delivery procedures

Genetic transformation of cereals by direct DNA delivery via microprojectile bombardment has become an established procedure in recent years. But the derivation of functional transgenic plants, especially in wheat, is still problematic, mainly due to low efficiency of DNA delivery and the reduced regeneration capability of microprojectile-bombarded tissue. We focussed on these two aspects and found that the regeneration of scutellar calli of wheat can be rendered highly efficient and considerably accelerated by a liquid culture phase in screen rafts. We also found that the expression of a reporter gene following DNA delivery by microprojectile can be improved by maintaining the scutellar calli in 0.25 M mannitol before and after bombardment, by bombardment in the presence of silver thiosulfate and Ca(NO3)2 (rather than CaCl2) and by the elimination of spermidine from the DNA/microprojectile mixture. A protocol that includes all these features leads to several-fold higher transient expression of the reporter gene than have previously published procedures.

Alteration of drug responsiveness in guinea-pig lung anaphylaxis using different antigen challenge concentrations

Antihistamine-resistant anaphylactic bronchospasm in guinea pigs is increased with increasing doses of antigen (ovalbumin, OA) challenge. This was observed in passively and actively sensitized animals, and by both i.v. and aerosol routes of antigen challenge. At a challenge concentration of 100 mg/kg OA, antihistamines were virtually inactive. Indeed, the resulting bronchospasm was inhibited by isoproterenol, theophylline and ketotifen but not any anticholinergics, anti-5HT, SRS-A antagonists, arachidonic acid lipoxygenase inhibitors or antiallergic drugs. However, in the presence of chlorpheniramine, the response was antagonized by SRS-A antagonists (FPL 55712 and isamoxole), but not the lipoxygenase inhibitors (BW 755C, ETYA, NDGA and phenidone). This suggests that the antihistamine-resistant bronchospasm produced in guinea pigs challenged with high antigen concentrations might be the result of SRS-A release. This is by no means certain since the currently available SRS-A antagonists possess other mechanisms of action; furthermore, the failure of lipoxygenase inhibitors to influence this response is not consistent with a role for SRS-A. Elucidation of the mechanism of the antihistamine-resistant bronchospasm awaits development of more specific SRS-A antagonists.

[Nutrient and fiber content of infant food]

The food given to 50 infants growing up in their family and 23 infants nursed in crèches was chemically analyzed in order to ascertain the nutrient and dietary fibre contents. The babies' age was between 6 and 12 months. The determination of energy percentages revealed a clear shift in favour of carbohydrates. Based on 1000 calories, the infants received 7.5-8.5 g of dietary fibre per day. Sodium content was too high whereas the iron intake was definitely insufficient. The baby food prepared in the family only showed slight differences in comparison with the food administered in crèches.

[Fiber and nutritional content of infant food]

50 mothers with healthy, already weaned babies of between 6 and 9 months old took part of the study. The babies consumed 7.5 g of dietary fibre per 1000 calories daily. The sources of energy ratio showed a definite trend in favour of carbohydrates. The proportion of sodium was extremely high. The supply of iron proved to be greatly deficient.