Association of glutathione S-transferases M1, P1 and T1 variations and risk of late-onset Alzheimer’s disease

Objective: Late-onset Alzheimer’s disease (AD) is a genetically heterogeneous neurodegenerative disorder. Associations of the glutathione S-transferases (GSTs) polymorphisms with the risk factors for AD have not been definitely confirmed. We investigated the association of GSTM1 and GSTT1 null deletion and GSTP1 313 A/G polymorphisms and the risk of AD in an Iranian population.

Methods: The case group consisted of 280 individuals with AD and the control group included 168 age-matched healthy individuals. The genotyping of the GSTP1 polymorphism was determined by PCR-RFLP and the GSTM1 and GSTT1 deletions were done by multiplex PCR method.

Results: The GSTP1 AG genotype was significantly lower (p = 0.005; OR = 0.57, 95% CI: 0.38–0.84) in the patients (41.1%) than the control group (56.5%). The GSTM1 null genotype was significantly higher (p < 0.001) in the patients (40.5%) than the control group (15.8%). The GSTT1 null genotype was significantly higher (p < 0.038) in the patients (31.2%) than the control group (21.5%). The patients homozygous for the GSTM1 and GSTT1 null alleles showed a 3.5 and 1.5-fold increased risk of AD, respectively. There were interaction between GSTP1 AG genotype and absence of APOE e4 allele (p = 0.001), as well as presence of APOE ε4 and GSTM1 null genotype (p < 0.0001).

Conclusion: These findings suggested that GSTM1 and GSTT1 null deletions may be associated with susceptibility to AD and people with APOE e4 and GSTM1 null deletion have a higher increased risk for Late-onset AD in Iranian population.     

Emerging role of neuregulin-1beta1 in pathogenesis and progression of multiple sclerosis

<正>Multiple sclerosis (MS) is a chronic immune-mediated disorder of the central nervous system (CNS) that causes focal demyelinating lesions,followed by axonal and neuronal degeneration.Several genetic and environmental factors are found to be associated with MS incidence.While MS etiology seems to be m ultifactorial and needs further elucidation,     

Compensatory redistribution of neuroligins and N-cadherin following deletion of synaptic β1-integrin

β1-containing integrins are required for persistent synaptic potentiation in hippocampus and regulate hippocampal-dependent learning. Based largely on indirect evidence, there is a prevailing assumption that β1-integrins are localized at synapses, where they contribute to synapse adhesion and signaling, but this has not been examined directly. Here we investigate the fine localization of β1-integrin in adult mouse hippocampus using high-resolution immunogold labeling, with a particular emphasis on synaptic labeling patterns. We find that β1-integrins localize to synapses in CA1 and are concentrated postsynaptically. At the postsynaptic membrane, β1-integrins are found more commonly clustered near active zone centers rather than at the peripheral edges. In mice harboring a conditional deletion of β1-integrins, labeling for N-cadherin and neuroligins increases. Western blots show increased levels of N-cadherin in total lysates and neuroligins increase selectively in synaptosomes. These data suggest there is a dynamic, compensatory adjustment of synaptic adhesion. Such adjustment is specific only for certain cell adhesion molecules (CAMs), because labeling for SynCAM is unchanged. Together, our findings demonstrate unequivocally that β1-integrin is an integral synaptic adhesion protein, and suggest that adhesive function at the synapse reflects a cooperative and dynamic network of multiple CAM families.     

The specificity and molecular basis of α1-adrenoceptor and CXCR chemokine receptor dimerization

It is now well established that rhodopsin-like, family-A G protein-coupled receptors (GPCRs) can exist within homo- and heterodimeric/oligomeric complexes. However, limited information is currently available on the molecular basis of these interactions or their selectivity. Using the alpha1-adrenoceptor family as a model, this has been examined using assays including coimmunoprecipitation, saturation bioluminescence resonance energy transfer (BRET), time-resolved fluorescence resonance energy transfer (FRET), and bimolecular fluorescence complementation. We demonstrate key roles for transmembrane helices I and IV in homodimeric/oligomeric interactions of the alpha1b-adrenoceptor and suggest that other interactions indicate that this GPCR can exist as a higher-order oligomeric complex. Literature reports on heterodimerization between chemokine receptor family members and the effects or otherwise of agonist ligands are complex. It was recently indicated that although the CXCR2 receptor is able to homodimerize, this is not the case for the closely related CXCR1 receptor and that these two GPCRs do not heterodimerize. We have reinvestigated these issues using combinations of coimmunoprecipitation, saturation BRET, and a novel endoplasmic reticulum-trapping strategy. Unlike the previous report, we demonstrate that CXCR1 is able to both homodimerize and heterodimerize with the CXCR2 receptor and that the relative affinity of these interactions suggests that with coexpression of these two GPCRs a random mixture of homo- and heterodimers will be present.     

Interaction of α-2-macroglobulin and HSV-1 during infection of neuronal cells

We describe the effect of pretreatment with alpha-2-macroglobulin (A2M) on the susceptibility of the human neuroblastoma SKNMC cell line to infection by herpes virus type 1 (HSV-1). ELISA and co-immunoprecipitation experiments confirmed the A2M-HSV-1 interaction in vitro. Indirect immunofluorescence shows that A2M exacerbated the cytopathic effect induced after HSV-1 infection. However, A2M-pretreated SKNMC cells notably produced fewer HSV-1 particles than did the untreated cells, suggesting that A2M could induce a restrictive infection. Furthermore, high levels of HSV-1 and A2M induced the production of nitric oxide (NO) in SKNMC. Preliminary results suggest that A2M might induce apoptosis in HSV-1-infected cells. These findings affirm the conclusion that A2M may interact directly with HSV-1 and modulate the course of the infection in SKNMC human neuroblastoma cells.     

Association of interleukin 1β polymorphisms and haplotypes with Alzheimer's disease

Our study aimed to associate IL-1β and IL-1RN polymorphisms with AD disease in comparison with elderly control group from S?o Paulo - Brazil. We genotyped 199 Alzheimer's disease (AD) patients, 165 elderly control and 122 young control samples, concerning VNTR (IL-1RN) and -511C>T and -31T>C (IL-1β) polymorphisms. Our findings revealed that -511C/-31T/2-repetitions VNTR haplotype had a protective effect for AD when compared to EC (p=0.005), whereas -511C/-31C/1-repetition VNTR haplotype was associated as a risk factor for AD (p=0.021). Taken together, we may suggest that there is a relevant role of IL-1 genes cluster in AD pathogenesis in this Brazilian population.     

Effects of reboxetine and sertraline treatments alone and in combination on the binding properties of cortical NMDA and β1-adrenergic receptors in an animal model of depression

Summary. Changes to the binding properties of cortical N-methyl-D-aspartic acid (NMDA) and beta-adrenergic receptors have both been reported as potential indicators of antidepressant activity. In the present investigation we examined the effects of the noradrenaline reuptake inhibitor, reboxetine, the serotonin reuptake inhibitor, sertraline, alone and in combination on the binding properties of cortical NMDA receptors and cortical β₁-adrenoceptors following 14 days of treatment in the olfactory bulbectomized rat model of depression. A decrease in the potency of glycine to displace the strychnine insensitive glycine antagonist [³H] 5,7 dichlorokynurenic acid (5,7 DCKA) was observed in cortical homogenates of OB rats when compared to sham-operated controls. Similarly, treatment with the combination of reboxetine and sertraline for 14 days produced a decrease in the potency of glycine when compared to vehicle treated controls. By contrast neither olfactory bulbectomy or drug treatment significantly altered basal or glycine enhanced binding of the non-competitive NMDA antagonist [³H] MK-801 in cortical homogenates. Reboxetine alone, and in combination with sertraline, down-regulated [³H]-CGP 12177 (a selective β-adrenoceptor antagonist) binding in both OB and sham-operated animals. The lack of a bulbectomy effect in the [³H] CGP-12177 binding assay, and the fact that olfactory bulbectomy and antidepressant treatments produce a similar change to the potency of glycine at the NMDA receptor, suggests that these tests do not provide a neurochemical marker for either the behavioral hyperactivity deficit or antidepressant response in the model. Received February 6, 2000; accepted March 6, 2000     

HIF-1α Genetic Variants and Protein Expression Confer the Susceptibility and Prognosis of Gliomas

To investigate the role of HIF-1α genetic polymorphism of c.1772C>T and c.1790G>A in the incidence and prognosis of gliomas in a Chinese cohort, a total of 387 gliomas patients and 437 age- and sex-matched healthy controls were recruited. The genetic polymorphism of c.1772C>T and c.1790G>A was determined. We found that the genotype distribution at c.1772C>T showed significant difference between patients and controls. Multivariable analyses showed a significantly higher risk for gliomas in 1772TT genotype carriers (odds ratio 2.68, with CC as reference). In addition, we also found a significantly higher risk for grade III + IV gliomas was observed in 1772TT genotype carriers (odds ratio 2.21, with CC as reference). The overall survival rates in patients with 1772TT or 1772CT genotype were markedly lower compared with patients with CC (both P < 0.01). Our in vitro studies revealed that HIF-1α regulates the proliferation, migration and invasion of human glioma U251 cells. This study suggests that the c.1772C>T polymorphisms may be used as a molecular marker for gliomas occurrence, grades and clinical outcome in gliomas patients.     

Expression of macrophage inflammatory protein-1α and monocyte chemoattractant protein-1 in glioma-infiltrating microglia: involvement of ATP and P2X₇ receptor

Chemokines can be produced by gliomas, which mediate the infiltration of microglia, a characteristic feature of glioma‐associated neuropathogenesis. ATP that is released at a high level from glioma has been reported to play a regulatory role in chemokine production in cultured glioma cells. The objective of this study was to define the potential role of extracellular ATP in the regulation of macrophage inflammatory protein‐1α (MIP‐1α) and monocyte chemoattractant protein‐1(MCP‐1) expression in glioma‐associated microglia/macrophages. The results showed that Iba1⁺ and ED1⁺ microglia existed in the tumor at 3 and 7 day after injection of C6 glioma cells into the rat cerebral cortex (dpi). ED1⁺ microglia/macrophages or Iba1⁺ microglia in the glioma were also colocalized to MIP‐1α‐ and MCP‐1‐expressing cells. In vitro study indicated that treatment with ATP and BzATP (an agonist for ATP ionotropic receptor P2X₇R) caused an increase in the intracellular levels of microglial MIP‐1α and MCP‐1. By using an extracellular Ca²⁺ chelator (EGTA) and P2X₇R antagonists, oxidized ATP (oxATP) and brilliant blue G (BBG), we demonstrated that BzATP‐induced production of MIP‐1α and MCP‐1 levels was due to P2X₇R activation and Ca²⁺‐dependent regulation. Coadministration of C6 glioma cells and oxATP into the rat cerebral cortex resulted in a reduction of MIP‐1α‐ and MCP‐1‐expressing microglia/macrophages. We suggest, based on the results from in vivo and in vitro studies, that a massive amount of ATP molecules released in the glioma tumor site may act as the regulator with P2X₇R signaling that increases MIP‐1α and MCP‐1 expression in tumor‐infiltrating microglia/macrophages. © 2010 Wiley‐Liss, Inc.     

Neuroprotective and anti-inflammatory effects of a therapy combining agonists of nicotinic α7 and σ1 receptors in a rat model of Parkinson's disease

To date there is no treatment able to stop or slow down the loss of dopaminergic neurons that characterizes Parkinson's disease. It was recently observed in a rodent model of Alzheimer's disease that the interaction between the α7 subtype of nicotinic acetylcholine receptor(α7-nAChR) and sigma-1 receptor(σ1-R) could exert neuroprotective effects through the modulation of neuroinflammation which is one of the key components of the pathophysiology of Parkinson's disease. In this context, the aim of the present study was to assess the effects of the concomitant administration of N-(3 R)-1-azabicyclo[2.2.2]oct-3-yl-furo[2,3-c]pyridine-5-carboxamide(PHA) 543613 as an α7-nAChR agonist and 2-(4-morpholinethyl) 1-phenylcyclohexanecarboxylate(PRE)-084 as a σ1-R agonist in a well-characterized 6-hydroxydopamine rat model of Parkinson's disease. The animals received either vehicle separately or the dual therapy PHA/PRE once a day until day 14 postlesion. Although no effect was noticed in the amphetamine-induced rotation test, our data has shown that the PHA/PRE treatment induced partial protection of the dopaminergic neurons(15–20%), assessed by the dopamine transporter density in the striatum and immunoreactive tyrosine hydroxylase in the substantia nigra. Furthermore, this dual therapy reduced the degree of glial activation consecutive to the 6-hydroxydopamine lesion, i.e, the 18 kDa translocation protein density and glial fibrillary acidic protein staining in the striatum, and the CD11 b and glial fibrillary acidic protein staining in the substantia nigra. Hence, this study reports for the first time that concomitant activation of α7-nAChR and σ1-R can provide a partial recovery of the nigro-striatal dopaminergic neurons through the modulation of microglial activation. The study was approved by the Regional Ethics Committee(CEEA Val de Loire n°19) validated this protocol(Authorization N°00434.02) on May 15, 2014.     

Sexually dimorphic expression of hypothalamic estrogen receptors α and β and Kiss1 in neonatal male and female rats

Release of gonadotropins in adult rodents is sex specific and dependent upon kisspeptin (Kiss1) neurons. This crucial pathway within the hypothalamic-pituitary-gonadal (HPG) axis is profoundly influenced by neonatal estrogens, which induce a male-like phenotype. Classically, estrogen activity is mediated via the estrogen receptors α and β (ERα and ERβ), but the relative roles each plays in organizing the sex-specific ontogeny of kisspeptin signaling pathways remain unresolved. Thus, the present study used in situ hybridization histochemistry (ISHH) to map the temporal and sexually dimorphic neonatal mRNA expression profiles of ERα, ERβ, and Kiss1 in the anterioventral periventricular nucleus (AVPV), medial preoptic area (MPOA), ventromedial nucleus (VMN), and arcuate nucleus (ARC), all regions critical for kisspeptin regulation of gonadotropin secretion. In general, females had higher levels of ERα, in all regions examined, a sex difference that persisted until postnatal day (PND) 19 except in the ARC. Males had significantly more ERβ expression in the AVPV at birth, but this sex difference was lost and then re-emerged on PND 19, with females having more than males. VMN ERβ levels were higher in females until PND 19. Kiss1 was not detectable until PND 11 in the anterior hypothalamus, but expression levels were equivalent at birth in the ARC. By PND 2, ARC ERα and Kiss1 levels were abundant, sexually dimorphic (higher in females), and, respectively, showed a U- and a bell-shaped pattern with age. Sex differences in ARC Kiss1 expression provide evidence that Kiss1 may play a role in the sexual dimorphic organization of the neonatal brain. These detailed profiles of neonatal Kiss1 and ERs mRNA levels will help elucidate the relative roles each plays in the sex-specific, estrogen-dependent organization of gonadotropin signaling pathways.     

Expression of 8-oxoguanine DNA glycosylase 1 (OGG1) and the level of p53 and TNF-αlpha proteins in peripheral lymphocytes of patients with Alzheimer's disease

The aim of the study was to determine the extent of oxidative DNA damage (levels of 8-oxo2dG) and expression of OGG1 and p53 and TNF-α proteins in lymphocytes of Alzheimer's disease (AD) patients and a control group. The studies were conducted on 41 patients with AD, including 25 women and 16 men aged 34-84 years. The control group included 51 individuals, 20 women and 31 men aged 22-83 years. The level of 8-oxo2dG was determined using HPLC/EC/UV, and the level of OGG1 and p53 and TNF-α proteins was determined with the Western blot method. The results showed that both proteins participating in DNA repair (OGG1, p53) and the inflammatory protein TNF-α are involved in pathogenesis of neurodegenerative diseases. It also seems that a specific system for DNA repair (OGG1) may contribute to downregulation of the inflammatory factor (TNF-α) level, especially in the early stages of dementia. Moreover, the results showed that p53 protein can fulfil its function in DNA damage repair only in early stages of dementia. It is possible that OGG1 and p53 and TNF-α proteins together or separately may be involved in pathogenesis of AD by repair of oxidative DNA damage and/or apoptosis.     

Effects of acute and repeated administration of Staphylococcal enterotoxin A on Morris water maze learning, corticosterone and hippocampal IL-1β and TNFα

Staphylococcal enterotoxin A (SEA) is a bacterial superantigen that induces pronounced T cell expansion and cytokine production. In addition, SEA activates the HPA axis and forebrain regions relevant to cognitive functions. Since learning-related cognitive changes have not been assessed in response to SEA, spatial learning in the Morris water maze (MWM) was determined in male C57BL/6 J mice subjected to acute or repeated injections of 5 μg SEA or Saline. Injections were given 2 h prior to 4-5 days of hidden platform sessions. Animals were then rested for 1 month and given retraining without further injections. In addition, splenic IL-1β, IL-2 and TNFα, plasma corticosterone, and hippocampal IL-1β and TNFα were measured after the regimen of treatment used in the behavioral experiments. The results showed no learning impairment following acute or repeated SEA challenge. Moreover, when retested 1 month later, and without further injections, the SEA group showed more rapid relearning of the MWM. This suggested that coincidental superantigenic T cell activation and training served to promote long-term improvement in recovery of learning. Furthermore, repeated SEA challenge continued to drive increases in plasma corticosterone, but with a compensatory reduction in hippocampal IL-1β. However, while hippocampal TNFα was reduced after acute and repeated SEA treatment, this was not statistically significant. In view of the importance of modest glucocorticoid elevations and hippocampal IL-1β in promoting contextual learning, the data point to the hypothesis that SEA promotes long-term plasticity by restraining disruptive increases in hippocampal IL-1β, and possibly TNFα, during learning.     

Single Nucleotide Polymorphism and Production of IL-1β and IL-10 Cytokines in Febrile Seizures

Inflammation and genetics may play a role in the pathogenesis of febrile seizures. The aim of this study was to investigate the spontaneous and lipopolysaccharide (LPS)-induced production of IL-1β and IL-10, and the association between IL-1β (-511) and IL-10 (-1082) single nucleotide polymorphisms with LPS-induced cytokine production. The study included 92 febrile seizure patients and 132 healthy controls. First, we isolated genomic DNA and by using PCR-RFLP we genotyped the individuals for the cytokines gene polymorphism. Second, peripheral mononuclear cells of the individuals were isolated and stimulated with LPS to measure secretion capacity of IL-1β and IL-10 using specific ELISA kits. We found that both the IL-1β and IL-10 production was increased in febrile seizures. The rapid increase of IL-1β production in the supernatants of the LPS-induced cells was significantly higher at the fourth and the twenty-fourth hours in febrile and complex febrile seizures, respectively. The distribution of IL-10 (-1082) G allele differs significantly between cases and controls. The IL-1β (-511) G/A and the IL-10 (-1082) G/A genotype combination was found to be higher in patients with febrile seizure. Our results showed that IL-1β and IL-10 production was not influenced by the single nucleotide polymorphisms in the pathogenesis of febrile seizures.     

Arg972 insulin receptor substrate-1 polymorphism and risk and severity of Alzheimer’s disease

We explored the association between the Arg972 insulin receptor substrate-1 (IRS1) polymorphism and the risk and severity of Alzheimer’s disease (AD). We genotyped the Arg972 IRS1 (rs1801278) polymorphism in 1123 pairs of age, sex, body mass index, residence area and education level-matched Han Chinese AD patients and controls. AD severity was assessed with Mini-Mental State Examination (MMSE) scores. The AA (homozygous Arg972 IRS1) and GA (heterozygous Arg972 IRS1) genotypes were associated with an increased risk of AD after adjustment for comorbidities including type 2 diabetes mellitus, coronary heart disease, and hypertension (p < 0.001; adjusted odds ratio [OR] 3.93 and 2.90, respectively). The A allele was associated with an increased risk of AD after adjustment for comorbidities (p < 0.001; adjusted OR 2.26; 95% confidence interval 1.92–2.80). The percentage of Arg972 IRS1 AA homozygotes was higher in the MMSE score ⩽14 category than in the MMSE score 15–26 category overall and in each age group (p < 0.001), while the wild type IRS1 GG homozygotes were predominantly found in the MMSE score 15–26 category overall and in each age group. The GG homozygote group had higher MMSE score than the GA heterozygote group, which in turn had higher MMSE score than the AA homozygote group overall and in each age group (p < 0.05). In conclusion, the Arg972 IRS1 polymorphism is an independent risk factor for AD and the A allele has a gene dosage effect on AD severity in Han Chinese. This study adds fresh insights into the pathogenesis of AD.     

Cloning and functional expression of rat eag2, a new member of the ether-à-go-go family of potassium channels and comparison of its distribution with that of eag1

A second mammalian gene for the ether-à-go-go (eag) potassium channel has been cloned from the rat, and its predicted protein sequence is 70% identical to that of rat ether-à-go-go1 with a further 10% conservatively replaced residues. The rat eag2 mRNA was predominantly expressed in neural tissue and was not detected in adult skeletal, cardiac, or smooth muscle. Within the brain, its distribution overlaps that of rat ether-à-go-go1 in specific regions within the cortex and olfactory bulb, but was differentially distributed in other locations, being scanty within the cerebellum, and most notably present in the thalamus, inferior colliculus, and certain brainstem nuclei. Heterologous expression of rat eag2 in HEK-293 cells gave rise to a voltage-gated, noninactivating potassium current, active at the cells' resting potential and blocked by low nanomolar concentrations of cytosolic calcium. Thus, in neurones, this current is likely to impart a modulation in membrane conductance, which is sensitively responsive to resting internal calcium, and levels of electrical activity.     

Effect of σ1 receptor antagonism on ethanol and natural reward seeking

σ1 Receptors have been implicated in cognitive function, anxiety, depression, and the regulation of stress responses. In addition, σ1 receptors have been shown to participate in the behavioral and motivational effects of psychostimulants. Recent studies have shown that σ1 receptor antagonism prevents ethanol-induced conditioned place preference in mice and excessive drinking in alcohol-dependent or alcohol-preferring rats. Therefore, this study was designed to determine whether this role for σ1 receptors extends to ethanol-seeking behavior using an animal model of relapse and tested whether the suppressant effect of a potent σ1 receptor antagonist, BD1047, generalizes to natural reward-seeking behavior. Two separate groups of rats were trained to orally self-administer 10% (w/v) ethanol or a highly palatable reinforcer, 3%/0.125% (w/v) glucose/saccharin (SuperSac), in the presence of a discriminative stimulus (S). Following extinction, during which the reinforcers and S were withheld, the presentation of the ethanol or SuperSac S produced comparable recovery of responding. BD1047 (1-20 mg/kg) exerted similar behavioral effects on both ethanol S-induced and SuperSac S-induced reinstatement, with the prevention of conditioned reinstatement only at the highest BD1047 dose. The present results show that σ1 receptor blockade under the present conditions exerts similar effects on conditioned reinstatement induced by ethanol-related and SuperSac-related stimuli, suggestive of overlapping neural mechanisms that control ethanol and natural reward seeking.     

Comorbidity between epilepsy and depression: Role of hippocampal interleukin-1β

Depression is a frequent comorbidity of temporal lobe epilepsy (TLE); however, its mechanisms remain poorly understood and effective therapies are lacking. Augmentation of hippocampal interleukin-1β (IL-1β) signaling may be a mechanistic factor of both TLE and clinical depression. We examined whether pharmacological blockade of hippocampal interleukin-1 receptor exerts antidepressant effects in an animal model of comorbidity between TLE and depression, which developed in Wistar rats following pilocarpine status epilepticus (SE). In post-SE animals, depression-like state was characterized by behavioral equivalents of anhedonia and despair; dysregulation of the hypothalamo–pituitary–adrenocortical axis; compromised raphe–hippocampal serotonergic transmission. Two-week long bilateral intrahippocampal infusion of human recombinant Interleukin-1 receptor antagonist (IL-1ra) improved all of the examined depressive impairments, without modifying spontaneous seizure frequency and without affecting normal parameters in naïve rats. These findings implicate hippocampal IL-1β in epilepsy-associated depression and provide a rationale for the introduction of IL-1β blockers in the treatment of depression in TLE.     

The stressor Criterion-A1 and PTSD: A matter of opinion?

Considerable controversy exists with regard to the interpretation and definition of the stressor "A1" criterion for Post Traumatic Stress Disorder (PTSD). At present, classifying an event as either traumatic (satisfying DSM-IV Criterion-A1 for PTSD), or non-traumatic (life event) is determined by the rater's subjective interpretation of the diagnostic criteria. This has implications in research and clinical practice. Utilizing a sample of 860 Australian adults, this study is the first to provide a detailed examination of the impact of event categorization on the prevalence of trauma and PTSD. Overall, events classified as non-traumatic were associated with higher rates of PTSD. Unanimous agreement between raters occurred for 683 (79.4%) events. As predicted, the categorization method employed (single rater, multiple rater-majority, multiple rater-unanimous) substantially altered the prevalence of Criterion-A1 events and PTSD, raising doubts about the functionality of PTSD diagnostic criteria. Factors impacting on the categorization process and suggestions for minimizing discrepancies in future research are discussed.