Toxoplasma gondii, Herpesviridae and long-term risk of transition to first-episode psychosis in an ultra high-risk sample

BACKGROUND

Ultra high-risk (UHR) criteria were introduced to identify people at imminent risk of developing psychosis. To improve prognostic accuracy, additional clinical and biological risk factors have been researched. Associations between psychotic disorders and infections with Toxoplasma gondii and Herpesviridae have been found. It is unknown if exposure to those pathogens increases the risk of transition to psychosis in UHR cohorts.

METHODS

We conducted a long-term follow-up of 96 people meeting UHR criteria, previously seen at the Personal Assessment and Crisis Evaluation (PACE) clinic, a specialized service in Melbourne, Australia. Transition to psychosis was assessed using the Comprehensive Assessment of the At-Risk Mental State (CAARMS) and state public mental health records. The relationship between IgG antibodies to Herpesviridae (HSV-1, HSV-2, CMV, EBV, VZV) and Toxoplasma gondii and risk for transition was examined with Cox regression models.

RESULTS

Mean follow-up duration was 6.46 (±3.65) years. Participants who transitioned to psychosis (n = 14) had significantly higher antibody titers for Toxoplasma gondii compared to those who did not develop psychosis (p = 0.03). After adjusting for age, gender and year of baseline assessment, seropositivity for Toxoplasma gondii was associated with a 3.6-fold increase in transition hazard in multivariate Cox regression models (HR = 3.6; p = 0.036). No significant association was found between serostatus for Herpesviridae and risk of transition.

CONCLUSIONS

Exposure to Toxoplasma gondii may contribute to the manifestation of positive psychotic symptoms and increase the risk of transitioning to psychosis in UHR individuals.

The lack of association between herpes simplex virus 1 or Toxoplasma gondii infection and cognitive decline in the general population: An 11-year follow-up study

BACKGROUND

Inflammation has been suggested to be one, possibly treatable, cause of cognitive decline and dementia. The purpose of the present article was to investigate whether the herpes simplex virus 1 (HSV-1) or Toxoplasma gondii (T. gondii) infections are related to cognitive decline or dementia.

METHOD

The Health 2000 survey, conducted 2000-2001, is a population-representative sample of people over 30 years old that involved 7112 participants. The sample was followed up in the year 2011, in the Health 2011 study. At both time points, cognitive performance was assessed with two tests from the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) assessing verbal fluency and verbal learning. In addition, the abbreviated Mini-Mental State Examination was administered to people aged over 55. In addition, tests assessing reaction and movement time were performed at baseline. Dementia diagnoses from nationwide health care registers were followed up until the end of year 2013. The presence of HSV-1 and T. gondii immunoglobulin G (IgG) was determined by solid-phase immunoassay at baseline.

RESULTS

HSV-1 or T. gondii seropositivity, or IgG antibody levels, were not associated with cognitive decline when investigated as infection × time interactions. In addition, the infections were not associated with the risk of dementia.

CONCLUSIONS

In a large sample of participants that is representative of the whole country and with a long follow-up, the results suggest that latent HSV-1 or T. gondii infections are not related to either decline in cognitive performance or dementia risk.

Pathogen-mediated NMDA receptor autoimmunity and cellular barrier dysfunction in schizophrenia

Autoantibodies that bind the N-methyl-D-aspartate receptor (NMDAR) may underlie glutamate receptor hypofunction and related cognitive impairment found in schizophrenia. Exposure to neurotropic pathogens can foster an autoimmune-prone environment and drive systemic inflammation leading to endothelial barrier defects. In mouse model cohorts, we demonstrate that infection with the protozoan parasite, Toxoplasma gondii, caused sustained elevations of IgG class antibodies to the NMDAR in conjunction with compromised blood-gut and blood-brain barriers. In human cohorts, NMDAR IgG and markers of barrier permeability were significantly associated with T. gondii exposure in schizophrenia compared with controls and independently of antipsychotic medication. Combined T. gondii and NMDAR antibody seropositivity in schizophrenia resulted in higher degrees of cognitive impairment as measured by tests of delayed memory. These data underscore the necessity of disentangling the heterogeneous pathophysiology of schizophrenia so that relevant subsets eligible for NMDAR-related treatment can be identified. Our data aid to reconcile conflicting reports regarding a role of pathological NMDAR autoantibodies in this disorder.

Infections and exposure to anti-infective agents and the risk of severe mental disorders: a nationwide study

OBJECTIVE

Severe infections are associated with increased risks of mental disorders; however, this is the first large-scale study investigating whether infections treated with anti-infective agents in the primary care setting increase the risks of schizophrenia and affective disorders.

METHOD

We identified all individuals born in Denmark 1985-2002 (N = 1 015 447) and studied the association between infections treated with anti-infective agents and the subsequent risk of schizophrenia and affective disorders during 1995-2013. Cox regression analyses were adjusted for important confounders.

RESULTS

Infections treated with anti-infective agents were associated with increased risks of schizophrenia by a hazard rate ratio (HRR) of 1.37 (95%-CI = 1.20-1.57) and affective disorders by a HRR of 1.64 (95%-CI = 1.48-1.82), fitting a dose-response and temporal relationship (P < 0.001). The excess risk was primarily driven by infections treated with antibiotics, whereas infections treated with antivirals, antimycotics, and antiparasitic agents were not significant after mutual adjustment. Individuals with infections requiring hospitalization had the highest risks for schizophrenia (HRR = 2.05; 95%-CI = 1.77-2.38) and affective disorders (HRR = 2.59; 95%-CI = 2.31-2.89).

CONCLUSION

Infections treated with anti-infective agents and particularly infections requiring hospitalizations were associated with increased risks of schizophrenia and affective disorders, which may be mediated by effects of infections/inflammation on the brain, alterations of the microbiome, genetics, or other environmental factors.

Strain hypothesis of Toxoplasma gondii infection on the outcome of human diseases

The intracellular protozoan Toxoplasma gondii is an exceptionally successful food and waterborne parasite that infects approximately 1 billion people worldwide. Genotyping of T. gondii isolates from all continents revealed a complex population structure. Recent research supports the notion that T. gondii genotype may be associated with disease severity. Here, we (1) discuss molecular and serological approaches for designation of T. gondii strain type, (2) overview the literatures on the association of T. gondii strain type and the outcome of human disease and (3) explore possible mechanisms underlying these strain-specific pathology and severity of human toxoplasmosis. Although no final conclusions can be drawn, it is clear that virulent strains (e.g. strains containing type I or atypical alleles) are significantly more often associated with increased frequency and severity of human toxoplasmosis. The significance of highly virulent strains can cause severe diseases in immunocompetent patients and might implicated in brain disorders such as schizophrenia should led to reconsideration of toxoplasmosis. Further studies that combine parasite strain typing and human factor analysis (e.g. immune status and genetic background) are required for better understanding of human susceptibility or resistance to toxoplasmosis.

Influence of maternal infections on neonatal acute phase proteins and their interaction in the development of non-affective psychosis

Although primary infections with Toxoplasma gondii or herpes viruses during pregnancy are established teratogens, chronic maternal infections with these pathogens are considered far less serious. However, such chronic infections have been associated with neuropsychiatric disorders in the offspring. The risks of non-affective psychoses, including schizophrenia, in offspring associated with these exposures during pregnancy have not been completely defined. We used data from neonatal dried blood samples from 199 cases of non-affective psychosis and 525 matched controls (born 1975-1985). We measure immunoglobulin G antibodies directed at T. gondii, cytomegalovirus and herpes simplex virus type-1 and -2, as well as levels of nine acute phase proteins (APPs). We assessed the interaction between maternal antibodies and neonatal APP in terms of risk of non-affective psychosis. Among controls, maternal exposure to T. gondii or cytomegalovirus, but not to the other herpes viruses, was associated with significantly higher levels of neonatal APPs. Among cases, none of the maternal exposures were associated with any significant change in APPs. We observed increased RR for non-affective psychosis associated with maternal infection with T. gondii (odds ratio 2.1, 95% confidence interval 1.1-4.0) or cytomegalovirus (1.7, 0.9-3.3) only among neonates with low APP levels. These findings suggest that chronic maternal infection with T. gondii or cytomegalovirus affect neonatal markers of innate immunity. Deficient fetal immune responses in combination with maternal chronic infections may contribute to subsequent risk for psychosis. A greater understanding of the maternal-fetal immunological interplay may ultimately lead to preventive strategies toward neuropsychiatric disorders.

MicroRNA-132 dysregulation in Toxoplasma gondii infection has implications for dopamine signaling pathway

Congenital toxoplasmosis and toxoplasmic encephalitis can be associated with severe neuropsychiatric symptoms. However, which host cell processes are regulated and how Toxoplasma gondii affects these changes remain unclear. MicroRNAs (miRNAs) are small noncoding RNA sequences critical to neurodevelopment and adult neuronal processes by coordinating the activity of multiple genes within biological networks. We examined the expression of over 1000 miRNAs in human neuroepithelioma cells in response to infection with Toxoplasma. MiR-132, a cyclic AMP-responsive element binding (CREB)-regulated miRNA, was the only miRNA that was substantially upregulated by all three prototype Toxoplasma strains. The increased expression of miR-132 was also documented in mice following infection with Toxoplasma. To identify cellular pathways regulated by miR-132, we performed target prediction followed by pathway enrichment analysis in the transcriptome of Toxoplasma-infected mice. This led us to identify 20 genes and dopamine receptor signaling was their strongest associated pathway. We then examined myriad aspects of the dopamine pathway in the striatum of Toxoplasma-infected mice 5days after infection. Here we report decreased expression of D1-like dopamine receptors (DRD1, DRD5), metabolizing enzyme (MAOA) and intracellular proteins associated with the transduction of dopamine-mediated signaling (DARPP-32 phosphorylation at Thr34 and Ser97). Increased concentrations of dopamine and its metabolites, serotonin (5-HT) and 5-hydroxyindoleacetic acid were documented by HPLC analysis; however, the metabolism of dopamine was decreased and 5-HT metabolism was unchanged. Our data show that miR-132 is upregulated following infection with Toxoplasma and is associated with changes in dopamine receptor signaling. Our findings provide a possible mechanism for how the parasite contributes to the neuropathology of infection.

Genome-wide study of association and interaction with maternal cytomegalovirus infection suggests new schizophrenia loci

Genetic and environmental components as well as their interaction contribute to the risk of schizophrenia, making it highly relevant to include environmental factors in genetic studies of schizophrenia. This study comprises genome-wide association (GWA) and follow-up analyses of all individuals born in Denmark since 1981 and diagnosed with schizophrenia as well as controls from the same birth cohort. Furthermore, we present the first genome-wide interaction survey of single nucleotide polymorphisms (SNPs) and maternal cytomegalovirus (CMV) infection. The GWA analysis included 888 cases and 882 controls, and the follow-up investigation of the top GWA results was performed in independent Danish (1396 cases and 1803 controls) and German-Dutch (1169 cases, 3714 controls) samples. The SNPs most strongly associated in the single-marker analysis of the combined Danish samples were rs4757144 in ARNTL (P=3.78 × 10(-6)) and rs8057927 in CDH13 (P=1.39 × 10(-5)). Both genes have previously been linked to schizophrenia or other psychiatric disorders. The strongest associated SNP in the combined analysis, including Danish and German-Dutch samples, was rs12922317 in RUNDC2A (P=9.04 × 10(-7)). A region-based analysis summarizing independent signals in segments of 100 kb identified a new region-based genome-wide significant locus overlapping the gene ZEB1 (P=7.0 × 10(-7)). This signal was replicated in the follow-up analysis (P=2.3 × 10(-2)). Significant interaction with maternal CMV infection was found for rs7902091 (P(SNP × CMV)=7.3 × 10(-7)) in CTNNA3, a gene not previously implicated in schizophrenia, stressing the importance of including environmental factors in genetic studies.

Cytomegalovirus seropositivity and serointensity are associated with hippocampal volume and verbal memory in schizophrenia and bipolar disorder

INTRODUCTION

Cytomegalovirus (CMV) is a member of the herpesviridae family that has a limbic and temporal gray matter tropism. It is usually latent in humans but has been associated with schizophrenia, bipolar disorder and cognitive deficits in some populations. Hippocampal decreased volume and dysfunction play a critical role in these cognitive deficits. We hypothesized that CMV seropositivity and serointensity would be associated with hippocampal volume and cognitive functioning in patients with schizophrenia or bipolar disorder.

METHODS

102 healthy controls, 118 patients with bipolar disorder and 69 patients with schizophrenia performed the California Verbal Learning Test (CVLT) and had blood samples drawn to assess CMV IgG levels. A subgroup of 52 healthy controls, 31 patients with bipolar disorder and 27 patients with schizophrenia underwent T1 MRI for hippocampal volumetry. We analyzed the association between CMV serointensity and seropositivity with hippocampal volume. We also explored the correlation between CMV serointensity and seropositivity and CVLT scores.

RESULTS

In both patient groups but not in controls, higher CMV serointensity was significantly associated with smaller right hippocampal volume. Further, in the group of patients with schizophrenia but not bipolar disorder, CMV serointensity was negatively correlated with CVLT scores.

CONCLUSION

CMV IgG titers are associated with decreased hippocampal volume and poorer episodic verbal memory in patients with schizophrenia or bipolar disorder. The mechanism of this association warrants further exploration.

Persistent infection with neurotropic herpes viruses and cognitive impairment

BACKGROUND

Herpes virus infections can cause cognitive impairment during and after acute encephalitis. Although chronic, latent/persistent infection is considered to be relatively benign, some studies have documented cognitive impairment in exposed persons that is untraceable to encephalitis. These studies were conducted among schizophrenia (SZ) patients or older community dwellers, among whom it is difficult to control for the effects of co-morbid illness and medications. To determine whether the associations can be generalized to other groups, we examined a large sample of younger control individuals, SZ patients and their non-psychotic relatives (n=1852). Method Using multivariate models, cognitive performance was evaluated in relation to exposures to herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2) and cytomegalovirus (CMV), controlling for familial and diagnostic status and sociodemographic variables, including occupation and educational status. Composite cognitive measures were derived from nine cognitive domains using principal components of heritability (PCH). Exposure was indexed by antibodies to viral antigens.

RESULTS

PCH1, the most heritable component of cognitive performance, declines with exposure to CMV or HSV-1 regardless of case/relative/control group status (p = 1.09 × 10-5 and 0.01 respectively), with stronger association with exposure to multiple herpes viruses (β = -0.25, p = 7.28 × 10-10). There were no significant interactions between exposure and group status.

CONCLUSIONS

Latent/persistent herpes virus infections can be associated with cognitive impairments regardless of other health status.

Identification of a biological signature for schizophrenia in serum

Biomarkers are now used in many areas of medicine but are still lacking for psychiatric conditions such as schizophrenia (SCZ). We have used a multiplex molecular profiling approach to measure serum concentrations of 181 proteins and small molecules in 250 first and recent onset SCZ, 35 major depressive disorder (MDD), 32 euthymic bipolar disorder (BPD), 45 Asperger syndrome and 280 control subjects. Preliminary analysis resulted in identification of a signature comprised of 34 analytes in a cohort of closely matched SCZ (n=71) and control (n=59) subjects. Partial least squares discriminant analysis using this signature gave a separation of 60-75% of SCZ subjects from controls across five independent cohorts. The same analysis also gave a separation of ~50% of MDD patients and 10-20% of BPD and Asperger syndrome subjects from controls. These results demonstrate for the first time that a biological signature for SCZ can be identified in blood serum. This study lays the groundwork for development of a diagnostic test that can be used as an aid for distinguishing SCZ subjects from healthy controls and from those affected by related psychiatric illnesses with overlapping symptoms.

Toxoplasma and schizophrenia

Research on infectious agents as a possible cause of schizophrenia has become prominent in the past decade. Toxoplasma gondii has emerged as a prime candidate for a variety of reasons; (i) many studies have reported that individuals with schizophrenia, compared to controls, have a higher prevalence of antibodies to T. gondii, (ii) some individuals with adult toxoplasmosis develop psychotic symptoms similar to those of schizophrenia, (iii) epidemiologically, there are many similarities between toxoplasmosis and schizophrenia, (iv) antipsychotic drugs known to be effective in schizophrenia also inhibit some parasites, including T. gondii, (v) Toxoplasma has been shown to induce elevated levels of dopamine in experimentally infected animals (elevated dopamine is commonly seen in individuals with schizophrenia) and (vi) studies have shown that individuals with schizophrenia, compared to controls, have had greater exposure to cats in childhood. A number of questions remain concerning a role for Toxoplasma in the aetiology of schizophrenia, including the roles of strain variation, the timing and source of infection, and the role of host genes in determining disease susceptibility. The establishment of a firm association between Toxoplasma and the aetiology of schizophrenia and related disorders would represent a major breakthrough in the understanding of these disorders and would lead to novel methods for their treatment and prevention.

Are some cases of psychosis caused by microbial agents? A review of the evidence

The infectious theory of psychosis, prominent early in the twentieth century, has recently received renewed scientific support. Evidence has accumulated that schizophrenia and bipolar disorder are complex diseases in which many predisposing genes interact with one or more environmental agents to cause symptoms. The protozoan Toxoplasma gondii and cytomegalovirus are discussed as examples of infectious agents that have been linked to schizophrenia and in which genes and infectious agents interact. Such infections may occur early in life and are thus consistent with neurodevelopmental as well as genetic theories of psychosis. The outstanding questions regarding infectious theories concern timing and causality. Attempts are underway to address the former by examining sera of individuals prior to the onset of illness and to address the latter by using antiinfective medications to treat individuals with psychosis. The identification of infectious agents associated with the etiopathogenesis of schizophrenia might lead to new methods for the diagnosis, treatment and prevention of this disorder.

Lack of RIC-3 congruence with β2 subunit-containing nicotinic acetylcholine receptors in bipolar disorder

Nicotinic acetylcholine receptor (nAChR) dysfunction occurs in individuals with schizophrenia (SZ) and may also affect individuals with bipolar disorder (BP). The molecular mechanisms for these disease-associated cholinergic deficits are not known. In vitro, the protein RIC-3 (resistance to inhibitors of cholinesterase-3) aids the assembly and trafficking of alpha7-nAChRs but has unclear action on the biogenesis of alpha4/beta2-nAChRs. To evaluate RIC-3/nAChR dynamics in diseased and normal human brain tissue, we measured RIC-3, alpha7-, alpha4- and beta2-nAChRs transcript levels in postmortem prefrontal cortex of individuals with SZ (n=31), BP (n=28) and unaffected controls (NC, n=33). Of the 28 individuals with BP, 20 had a history of psychotic symptoms. We compared relative message abundances between diagnostic groups and tested correlations of RIC-3 with each nAChR message subtype. RIC-3 and alpha4 messages were significantly increased in BP compared with NC (RIC-3, P< or =0.002; alpha4, P< or =0.04). RIC-3 message was also upregulated in SZ (P< or =0.04). In BP with psychoses, RIC-3 and alpha4 levels were increased compared with BP without psychoses (both P< or =0.02) and compared with NC (RIC-3, P< or =0.0003; alpha4, P< or =0.004). In correlation regression analyses, RIC-3 expression was very highly correlated to alpha7, alpha4 and beta2 in NC (alpha7, P< or =2.5e-05; alpha4, P< or =2.5e-09; beta2, P< or =0.003) and in SZ (alpha7, P< or =1e-07; alpha4, P< or =7e-07; beta2, P< or =3e-09). RIC-3 also strongly correlated with alpha7 and alpha4 in BP (alpha7, P< or =0.003; alpha4, P< or =3.5e-07). RIC-3 was modestly correlated with beta2 in BP overall (P< or =0.04), but showed no significant correlation in BP with psychoses (P< or =0.31) compared with a significant correlation in BP without psychoses (P< or =0.007). In conclusion, coordinated RIC-3/alpha4 upregulation and discordant RIC-3/beta2 levels suggest that alpha4/beta2 nAChR deficits in BP may occur from dysregulated RIC-3 chaperoning of the beta2 nAChR subunit in a subset of patients affected by psychotic features.

Elevated levels of human endogenous retrovirus-W transcripts in blood cells from patients with first episode schizophrenia

We previously reported on the differential presence of transcripts related to the human endogenous retrovirus (HERV)-W family in cerebrospinal fluid and plasma from patients with first-episode schizophrenia compared with control individuals. Whether this is a consequence of qualitative or quantitative differences in transcription of genomic regions harboring HERV-W elements is not known. The purpose of the present study was therefore to characterize the transcribed HERV-W elements in mononuclear cells obtained from 30 patients first hospitalized for schizophrenia-related psychosis and from 26 healthy control individuals. We observed elevated total levels of HERV-W gag (2.1-fold, P < 0.01) but not env transcripts in the cells of patients compared with controls. By using the melting temperatures of the amplicons as a proxy marker for sequence identity, no absolute qualitative differences was detected between the two groups. Mapping of the detected transcripts identified several intronic and intergenic HERV-W elements transcribed in the cells, including elements previously considered transcriptionally silent. Element-specific assays revealed elevated levels of intronic transcripts containing HERV-W gag sequence from the putative gene PTD015 on chromosome 11q13.5 (1.6-fold, P < 0.05) in the patients compared with the controls. Thus, studies aiming to further understanding of complex human disease such as schizophrenia may need to be extended beyond the strictly protein-coding fraction of the transcriptome.

Novel alpha7 nicotinic receptor isoforms and deficient cholinergic transcription in schizophrenia

Abnormal alpha7 nicotinic acetylcholine receptor activity contributes to sensory gating and cognitive deficits in schizophrenic individuals. Negligible differences in alpha7 mRNA levels between disease and control states have led to conclusions that cholinergic dysfunction in schizophrenia (SZ) must occur post-transcriptionally. Alternatively, we propose that the dysregulation of splice variants of the alpha7 receptor could account for cholinergic deficiencies observed in this disease. Here, we isolated multiple alpha7 splice variants including exon deletions and those associated with a novel 124-127 base insertion following exon 4. Transcripts containing this new exon originated from sense strand-oriented RNA (vs. antisense), and in silico translations produced putative subunits with unique amino termini. Quantitative real-time polymerase chain reaction analyses indicated that one novel isoform was significantly downregulated (P < or = 0.03) in post-mortem prefrontal cortex of individuals with SZ (n = 35) compared with controls (n = 34). Ten brain regions (cerebellum, thalamus, corpus callosum, caudate, putamen and five areas of the cortex) were further screened for alpha7 isoforms in three individuals of each group. Semiquantitative analyses showed that each alpha7 mRNA subtype was present in each brain region, but all were particularly deficient in the corpus callosum in schizophrenics vs. controls (P < or = 0.0002 to 0.05 for different isoforms). Our data demonstrate that alpha7 transcription is altered in several ways in SZ, suggesting that transcription-level mechanisms could account in part for the impaired cholinergic neurotransmission observed in this disease.

Brain morphological changes associated with exposure to HSV1 in first-episode schizophrenia

Infectious agents have been proposed as one of the risk factors for schizophrenia. However, the data on the association of infectious agents with in vivo brain changes are scant. We evaluated the association of serological evidence of exposure to herpes simplex virus 1 (HSV1) with in vivo brain structural variations among first-episode antipsychotic-naive schizophrenia/schizoaffective disorder patients and control subjects. We assayed HSV1 immunoglobulin G (IgG) antibody in serum samples from 30 patients and 44 healthy subjects and obtained structural magnetic resonance imaging scans from the same individuals. There were proportionately more patients with elevated HSV1 antibody ratios than healthy comparison subjects (chi2=3.98, 1 df, P=0.046) and patients had significantly higher HSV1 IgG antibody ratios compared with healthy subjects. Using optimized voxel-based morphometry, we examined diagnosis by HSV1 serological status interaction followed by within- and between-group comparison across the serological status. We observed a diagnosis by HSV1 serological status interaction and a significant main effect of HSV1 serological status in the prefrontal gray matter. Patients exposed to HSV1 had decreased gray matter in Brodmann area 9 (dorsolateral prefrontal cortex) and 32 (anterior cingulate cortex) compared with patients without serological evidence of exposure to HSV1. HSV1-associated differences in brain structure were not detected among healthy subjects. These findings suggest that HSV1 exposure in schizophrenia is associated with specific regional gray matter differences that may not be attributable to medications, illness chronicity or comorbid substance use. This study provides suggestive evidence for a link between HSV1 exposure and some of the cerebral morphological changes often reported in schizophrenia.

Changes in region- and cell type-specific expression patterns of neutral amino acid transporter 1 (ASCT-1) in the anterior cingulate cortex and hippocampus in schizophrenia, bipolar disorder and major depression

Although, the pathogenetic mechanisms of schizophrenia, bipolar disorder, and major depression are not clearly understood, various neurotransmitter systems are reported to have altered expression patterns of their receptor and transporter proteins. Changes in the expression of the neutral amino acid transporter 1 (ASCT-1) protein in the anterior cingulate gyrus and the hippocampus were investigated using immunohistochemistry and western blotting. A significant decrease in ASCT-1 immunoreactivity in neurons in the cingulate cortex as well as astrocytes of the white matter was seen in schizophrenia. In bipolar disorder and major depression, similar results were seen for neurons. In the hippocampus, there was a striking loss of immunoreactivity on astrocytes, neurons and interneurons in multiple regions in schizophrenia and bipolar disorder, while only minor changes were seen in major depression. The altered expression of ASCT-1 in neurons and astrocytes reflects profound changes in glutamatergic neurotransmission and highlights a significant role of astrocytes in the pathophysiology of neurotransmission in these major psychiatric disorders.

Psychopathology in first-episode schizophrenia and antibodies to Toxoplasma gondii

OBJECTIVE

Environmental factors such as infectious agents may contribute to the psychopathology and aetiology of schizophrenia. Toxoplasma gondii (TG) is a candidate infectious agent as it is known to replicate within the human central nervous system and to alter behaviour in experimental animals.

METHOD

The relationship between antibodies to TG and psychopathological symptoms was examined in 34 first-episode patients with schizophrenia.

RESULTS

Results of regression analyses revealed that symptoms on admission, predictors of outcome, age and family history of psychiatric disease influenced the levels of antibodies to TG.

CONCLUSIONS

These results indicate that TG infections may play a role in the clinical manifestation of psychopathology in a subgroup of patients with schizophrenia.

Mitochondrial dysfunction in schizophrenia: evidence for compromised brain metabolism and oxidative stress

The etiology and pathophysiology of schizophrenia remain unknown. A parallel transcriptomics, proteomics and metabolomics approach was employed on human brain tissue to explore the molecular disease signatures. Almost half the altered proteins identified by proteomics were associated with mitochondrial function and oxidative stress responses. This was mirrored by transcriptional and metabolite perturbations. Cluster analysis of transcriptional alterations showed that genes related to energy metabolism and oxidative stress differentiated almost 90% of schizophrenia patients from controls, while confounding drug effects could be ruled out. We propose that oxidative stress and the ensuing cellular adaptations are linked to the schizophrenia disease process and hope that this new disease concept may advance the approach to treatment, diagnosis and disease prevention of schizophrenia and related syndromes.

Maternal cytokine levels during pregnancy and adult psychosis

We investigated levels of maternal cytokines in late pregnancy in relation to the subsequent development of adult schizophrenia and other psychoses in their offspring. The sample included the mothers of 27 adults with schizophrenia and other psychotic illnesses and 50 matched unaffected controls from the Providence cohort of the Collaborative Perinatal Project. Serum samples were analyzed for interleukin 1 beta (IL-1-beta), interleukin 2 (IL-2), interleukin 6 (IL-6), interleukin 8 (IL-8), and tumor necrosis factor alpha (TNF-alpha) by enzyme immunoassay. Maternal levels of TNF-alpha were significantly elevated among the case series (t = 2.22, p =.04), with evidence of increasing odds of psychosis in relation to higher cytokine levels. We did not find significant differences between case and control mothers in the serum levels of IL-1, IL-2, IL-6, or IL-8. These data support previous clinical investigations reporting maternal infections during pregnancy as a potential risk factor for psychotic illness among offspring.

The schizophrenia-rheumatoid arthritis connection: infectious, immune, or both?

Schizophrenia and rheumatoid arthritis share an impressive number of similarities. Both are chronic, relapsing diseases of unknown etiology. Both became prominent in the early 19th century and have prevalences of approximately 1% in North America and Europe. Both run in families, have pairwise concordance rates of approximately 30% among monozygotic twins, and are more common among individuals born in urban areas. For both diseases, studies have reported greater exposure to cats in childhood than in controls. Both diseases have been associated with similar class II HLA antigens. Both have also been suspected of having infectious etiology, with similar agents--retroviruses, herpesviruses including EBV, and Toxoplasma gondii--having been associated in some cases. Since there is also a well-documented inverse correlation between these two diseases, it is possible that they share a common infectious and/or immune etiology and that once a person gets one of the diseases then they are relatively immune to the other.

Immunohistochemical localization of phosphorylated glial fibrillary acidic protein in the prefrontal cortex and hippocampus from patients with schizophrenia, bipolar disorder, and depression

Increasingly, abnormalities of glial cell function have been implicated in pathological studies of the major mental illnesses (schizophrenia, bipolar disorder, and major depression). In a recent proteomic study, four isoforms of astrocytic glial fibrillary acidic protein (GFAP) were decreased in one or more of these diseases. In the current study, we sought to determine the immunohistochemical localization of phosphorylated GFAP (pGFAP) in the prefrontal cortex and hippocampus and to describe possible disease-related changes in the distribution of pGFAP containing astrocytes. In the prefrontal cortex, interlaminar astrocytes in layer I and stellate astrocytes in layers II and VI were labeled. Labeled cells were also present adjacent to blood vessels in the gyral white matter and in underlying white matter generally. In the hippocampus, labeled cells were present in the polymorphic layer of the dentate gyrus. In the prefrontal cortex, schizophrenia and major depression were characterized by decreased labeling of astrocytes adjacent to blood vessels. There were no significant differences between the diagnostic groups in the other prefrontal layers or in the hippocampus. These results suggest that reduced numbers or functional regulation of pGFAP containing astrocytes occurs in schizophrenia and major depression. The mechanism by which this deficit occurs is not known, but it may adversely effect the regulation of neuronal metabolism, communication, and response to injury.

Maternal infections and subsequent psychosis among offspring

BACKGROUND

We tested the hypothesis that maternal infections during pregnancy are associated with the subsequent development of schizophrenia and other psychoses in adulthood.

METHODS

We conducted a nested case-control study of 27 adults with schizophrenia and other psychotic illnesses and 54 matched unaffected control subjects (matched for sex, ethnicity, and date of birth) from the Providence, RI, cohort of the Collaborative Perinatal Project. We retrieved stored blood samples that had been obtained from these mothers at the end of pregnancy. These samples were analyzed for total class-specific immunoglobulins and for specific antibodies directed at recognized perinatal pathogens capable of affecting brain development.

RESULTS

Maternal levels of IgG and IgM class immunoglobulins before the mothers were delivered of their neonates were significantly elevated among the case series (t = 3.06, P =.003; t = 2.93, P =.004, respectively, for IgG and IgM immunoglobulin-albumin ratios). Secondary analyses indicated a significant association between maternal antibodies to herpes simplex virus type 2 glycoprotein gG2 and subsequent psychotic illness (matched t test = 2.43, P =.02). We did not find significant differences between case and control mothers in the serum levels of IgA class immunoglobulins, or in specific IgG antibodies to herpes simplex virus type 1, cytomegalovirus, Toxoplasma gondii, rubella virus, human parvovirus B19, Chlamydia trachomatis, or human papillomavirus type 16.

CONCLUSIONS

The offspring of mothers with elevated levels of total IgG and IgM immunoglobulins and antibodies to herpes simplex virus type 2 are at increased risk for the development of schizophrenia and other psychotic illnesses in adulthood.

Serial analysis of gene expression in the frontal cortex of patients with bipolar disorder

BACKGROUND

Bipolar disorder is a serious brain disease affecting more than a million individuals living in the USA. Epidemiological studies indicate a role for both genetic and environmental factors in the pathogenesis of this disorder.

AIM

To identify RNA transcripts that are up- or down-regulated in the frontal cortex regions of individuals with bipolar disorder.

METHOD

Serial analysis of gene expression (SAGE) and reverse transcriptase-polymerase chain reaction were used to identify RNA transcripts which are differentially expressed in the frontal cortex of brains obtained postmortem from individuals with bipolar disorder compared with other psychiatric and control conditions.

RESULTS

Levels of RNA transcripts encoding the serotonin transporter protein and components of the NF-kappa B transcription factor complex are significantly increased in individuals with bipolar disorder compared with unaffected controls. Increased levels of expression of these RNA transcripts were also detected in the brains of some individuals with schizophrenia and unipolar depression.

CONCLUSION

The SAGE technique offers promise for the characterisation of complex human brain diseases.

Retroviral RNA identified in the cerebrospinal fluids and brains of individuals with schizophrenia

Schizophrenia is a serious brain disease of uncertain etiology. A role for retroviruses in the etiopathogenesis of some cases of schizophrenia has been postulated on the basis of clinical and epidemiological observations. We found sequences homologous to retroviral pol genes in the cell-free cerebrospinal fluids (CSFs) of 10 of 35 (29%) individuals with recent-onset schizophrenia or schizoaffective disorder. Retroviral sequences also were identified in the CSFs of 1 of 20 individuals with chronic schizophrenia. However, retroviral sequences were not identified in any of the CSFs obtained from 22 individuals with noninflammatory neurological diseases or from 30 individuals without evidence of neurological or psychiatric diseases (chi(2) = 19.25, P < 0.001). The nucleotide sequences identified in the CSFs of the individuals with schizophrenia or schizoaffective disorder were related to those of the human endogenous retroviral (HERV)-W family of endogenous retroviruses and to other retroviruses in the murine leukemia virus genus. Transcription of RNA homologous to members of the HERV-W family of retroviruses also was found to be up-regulated differentially in the frontal cortex regions of brains obtained postmortem from individuals with schizophrenia, as compared with corresponding tissue from individuals without psychiatric diseases. The transcriptional activation of certain retroviral elements within the central nervous system may be associated with the development of schizophrenia in at least some individuals. The further characterization of retroviral elements within the central nervous system of individuals with schizophrenia might lead to improved methods for the diagnosis and management of this disorder.

Emerging technologies for large-scale screening of human tissues and fluids in the study of severe psychiatric disease

Neuropsychiatric diseases such as schizophrenia and bipolar disorder are major causes of morbidity throughout the world. Despite extensive searches, no single gene, RNA transcript, or protein has been found which can, on its own, account for these disorders. Recently, the availability of genomic tools such as cDNA microarrays, serial analysis of gene expression (SAGE) and large-scale sequencing of cDNA libraries has allowed researchers to assay biological samples for a large number of RNA transcripts. Similarly, proteomic tools allow for the quantitation of a large number of peptides and proteins. These methods include two-dimensional electrophoresis and surface-enhanced laser desorption/ionization (SELDI). We have initiated experiments which apply these techniques to the comparison of RNAs and proteins expressed in clinical samples obtained from individuals with psychiatric diseases and controls. These methods have the potential to identify pathways that are involved in the pathogenesis of complex psychiatric disorders. The characterization of these pathways may allow for the development of new methods for the diagnosis and treatment of schizophrenia, bipolar disorder, and other human psychiatric diseases.

Antibodies to Toxoplasma gondii in individuals with first-episode schizophrenia

We employed enzyme immunoassay (EIA) and Western blotting techniques to measure the level of antibodies to Toxoplasma gondii proteins in serum samples from 38 individuals undergoing their first episode of schizophrenia and from a group of matched control subjects. We found that the individuals with first-episode schizophrenia had significantly increased levels of IgG, IgM, and IgA class antibodies to Toxoplasma proteins, as compared with the control subjects.

Serum antibodies reactive with non-human primate retroviruses identified in acute onset schizophrenia

Schizophrenia is a pervasive neuropsychiatric disease of uncertain etiology. Previous studies have postulated that retroviruses may contribute to the etiology of some cases of schizophrenia. We examined the possible relationship between retroviral infection and schizophrenia by measuring antibodies to a number of different primate retroviruses in the sera of individuals undergoing their first hospitalization for this disease. Sera from patients with first onset schizophrenia and matched healthy controls were analyzed by immunoblot and enzyme linked immunosorbent assays using purified retrovirus antigens to identify and quantify antibodies reactive with retrovirus proteins. A significantly increased incidence of antibodies reactive to gag encoded proteins of Mason-Pfizer monkey virus (MPMV), baboon endogenous virus (BaEV) and simian retrovirus type 5 (SRV-5) was observed in the sera of schizophrenia patients compared to controls. The reactivity of the cases and controls displayed the greatest differences in terms of antibodies to the proteins of Mason-Pfizer monkey virus. Employing an algorithm of enzyme linked immunosorbent assay reactivity followed by immunoblot confirmation, we found that MPMV antibodies in 28.9% of the individuals with first episode schizophrenia patients as compared to 3.7% of the unaffected controls (P<0.009, Fisher's Exact Test). These studies are consistent with the occurrence of retrovirus replication in some individuals who are undergoing their first episode of schizophrenia.

The antecedents of psychoses: a case-control study of selected risk factors

Winter birth, urban birth and/or childhood residence, and perinatal complications have each been identified as environmental risk factors for the later development of schizophrenia, schizoaffective disorder, and bipolar disorder. A preliminary case-control study also identified cat exposure in childhood as a possible risk factor. To assess selected environmental events, including childhood exposure to pets, as possible risk factors for these diseases, a case-control telephone survey was carried out by the University of Maryland Survey Research Center for 264 mothers of cases and 528 mothers of matched controls. The cases were randomly selected mothers who were members of the National Alliance for the Mentally Ill, and whose children had been diagnosed with schizophrenia, schizoaffective disorder, or bipolar disorder. The controls were mothers randomly selected from the same telephone exchanges. For five of the 19 major variables, there were statistically significant differences between cases and controls: fever during pregnancy, complications during delivery, city or suburban residence at birth, cat ownership between birth and age 13, and breast-feeding. In a multivariate logistic regression including these five variables, each variable made a significant contribution. The finding of perinatal complications, urban/suburban residence at birth, and cat ownership in childhood as risk factors for the later development of psychoses confirmed previous studies. Previous research on breast-feeding as a risk factor has yielded contradictory results. Additional research is needed to ascertain how such environmental risk factors interact with genetic risk factors. Understanding these could lead to better treatments and possible prevention strategies.

The stanley foundation brain collection and neuropathology consortium

The Stanley Foundation brain collection is an attempt to supplement existing brain collections for the purpose of promoting research on schizophrenia and bipolar disorder. Specimens are collected with the permission of the families in a standardized manner, with half of each specimen being frozen and half fixed in formalin. The Neuropathology Consortium is a subset of 60 specimens from the collection, well-matched groups of 15 each with diagnoses of schizophrenia, bipolar disorder, major depressive disorder without psychotic features, and normal controls. More than 75000 sections and blocks from the Consortium have been sent to over 50 research groups worldwide to carry out a wide variety of assessments. These data will be integrated to provide a more complete picture of the neuropathology of these disorders.

Seasonal birth patterns of neurological disorders

Existing seasonal birth studies were reviewed for multiple sclerosis (MS), Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis (ALS), epilepsy, cerebral palsy, congenital malformations of the central nervous system and mental retardation. Epilepsy appears to have the most consistent pattern, with an excess of births in winter and a deficit in September. MS, ALS and possibly Parkinson's disease appear to have an excess of spring births. Studies of cerebral palsy are not conclusive, although there are suggestions that there may be an excess of summer births. The findings for Alzheimer's disease, congenital malformations of the central nervous system, and mental retardation are contradictory and insufficient to draw any conclusions.

Disease-specific alterations in frontal cortex brain proteins in schizophrenia, bipolar disorder, and major depressive disorder. The Stanley Neuropathology Consortium

Severe psychiatric disorders such as schizophrenia, bipolar disorder and major depressive disorder are brain diseases of unknown origin. No biological marker has been documented at the pathological, cellular, or molecular level, suggesting that a number of complex but subtle changes underlie these illnesses. We have used proteomic technology to survey postmortem tissue to identify changes linked to the various diseases. Proteomics uses two-dimensional gel electrophoresis and mass spectrometric sequencing of proteins to allow the comparison of subsets of expressed proteins among a large number of samples. This form of analysis was combined with a multivariate statistical model to study changes in protein levels in 89 frontal cortices obtained postmortem from individuals with schizophrenia, bipolar disorder, major depressive disorder, and non-psychiatric controls. We identified eight protein species that display disease-specific alterations in level in the frontal cortex. Six show decreases compared with the non-psychiatric controls for one or more diseases. Four of these are forms of glial fibrillary acidic protein (GFAP), one is dihydropyrimidinase-related protein 2, and the sixth is ubiquinone cytochrome c reductase core protein 1. Two spots, carbonic anhydrase 1 and fructose biphosphate aldolase C, show increase in one or more diseases compared to controls. Proteomic analysis may identify novel pathogenic mechanisms of human neuropsychiatric diseases.

Endogenous retroviruses and schizophrenia

Retroviruses are biologically complex infectious agents which are capable of cellular infection and subsequent integration into the host genome. Retroviruses can exist in an endogenous form in which viral sequences are integrated into the human germline and are vertically transmitted in a Mendelian fashion. The transcriptional activation of these viral sequences in cells within the central nervous system can affect the transcriptional regulation of adjacent genes and result in alterations of neural functioning. This report discusses evidence for a possible role of endogenous retroviruses in the etiopathogenesis of schizophrenia and other human brain diseases. Evidence of endogenous retrovirus activity is manifested by the identification of viral sequences in the brains and cerebrospinal fluids of affected individuals. In addition, affected individuals display evidence of increased activity of virally-encoded reverse transcriptase. The identification of a retroviral component of schizophrenia would be consistent with genetic, environmental, and neurodevelopmental aspects of the disease process. The delineation of a role for retroviruses in disease pathogenesis might lead to new methods for the diagnosis and treatment of schizophrenia.

Familial and genetic mechanisms in schizophrenia

A distinction should be made between genetic aspects of schizophrenia and familial aspects. Genetic aspects of the disease have been reviewed and found to be deficient in many respects. Until recent years, familial factors were assumed to be psychological in origin, but this assumption is now discredited. Research efforts should focus on familial factors that are biological, especially infectious agents that may be transmitted within the family. Most infectious agents are influenced by predisposing genes. The etiology of schizophrenia, then, may turn out to involve biological familial infectious agents that are influenced by susceptibility genes governing the infectious process and the clinical expression of the disease.

Whole body protein turnover in children with human immunodeficiency virus (HIV) infection

The purpose of this study was to determine the rate of whole body protein turnover (WBPT) in human immunodeficiency virus (HIV)-infected children, and to determine the relationship between WBPT and growth. The rate of WBPT was calculated from the cumulative excretion of labeled urinary ammonia after a single intravenous dose of 15N-glycine in three groups of children: 1) HIV+ with growth retardation (HIV+ Gr); 2) HIV+ with normal growth (HIV+); and 3) HIV-uninfected with normal growth (HIV-). Twenty-six children between 2 and 11 y of age were studied (10 HIV+ Gr, 12 HIV+, 4 HIV-). All children were afebrile and free of acute infection during the study. Rates of WBPT (mean +/- SD) for the study groups were: HIV+ Gr, 12.2 +/- 4.8; HIV+, 10.7 +/- 5.1; and HIV-, 8.6 +/- 2.1 g.protein.kg-1.d-1 (NS, P > 0.05). Although not statistically significant, mean WBPT was 42% greater in HIV+ Gr, and 24% greater in HIV+ compared to HIV-. Statistically significant correlations were found between WBPT and Z scores for height (r = -0.39, P = 0.05) and weight-for-age (r = -0.51, P = 0.01) and dietary intake of protein (r = 0.39, P = 0.05), and between protein balance (synthesis-catabolism) and intakes of energy (r = 0.47, P = 0.02) and protein (r = 0.40, P = 0.04). There was no statistically significant correlation between WBPT and resting energy expenditure (r = 0.27, P = 0.19), or CD4 cell number (r = 0.05, P = 0.82). These data suggest an association between increased rates of protein turnover and low weight and height-for-age Z scores, and that it may be possible to achieve positive protein balance given an adequate intake of nutrients.

PCR-Enzyme immunoassay for detection of Streptococcus pneumoniae DNA in cerebrospinal fluid samples from patients with culture-negative meningitis

A PCR-based assay was developed to amplify a conserved region of the pneumococcal autolysin gene. The amplified product was labelled with digoxigenin-labelled dUTP and was detected with a biotin-labelled probe in an enzyme immunoassay (EIA). The assay was initially tested with suspensions of various serotypes of Streptococcus pneumoniae and other gram-positive and gram-negative bacteria and was then applied to cerebrospinal fluid (CSF) specimens from patients with meningitis and those with other neurological disorders. The assay detected all the serotypes of S. pneumoniae tested, whereas all the other bacterial strains tested were negative. Seven of the 8 CSF specimens positive for pneumococcus by culture or latex agglutination (LA) were positive by PCR-EIA, whereas all 10 specimens positive for other organisms were negative. Among 11 patients with clinically diagnosed meningitis but with negative culture and LA results, 5 were positive by PCR-EIA. The assay was negative for all but one patient without meningitis; it was positive with the CSF from a child with immunodeficiency and pneumococcal abscesses on the scalp. PCR-EIA is a useful tool for the diagnosis of meningitis, especially when culture and LA are negative because of prior antibiotic treatment.

Resting energy expenditure and body composition in children with HIV infection

The purpose of this study was to determine whether alterations in body composition, resting energy expenditure (REE), and dietary energy intake are associated with growth retardation in HIV-positive children. Body composition (deuterium oxide dilution, skinfold measurements), REE (indirect calorimetry), and energy intake (24-hour weighed food intake) were evaluated in three groups: HIV-positive with growth retardation (HIV+Gr), HIV-positive with normal growth (HIV+); and HIV-uninfected with normal growth (HIV-). Children were between 2 and 11 years of age, afebrile, and free from acute infection. Forty-two children (13 HIV+Gr, 19 HIV+, 10 HIV-) were studied. Lean body mass was significantly reduced in HIV+Gr compared with HIV- (p < .05), and fat mass was significantly reduced in HIV+Gr and HIV+ compared with HIV- (p < .05). The percentages of lean and fat mass were not significantly different between groups, suggesting that differences in lean and fat mass were proportional to differences in body size. Consistent with reduced lean body mass, mean REE was significantly lower in HIV+Gr compared with HIV- (p < .05). Differences in mean REE/kg of body weight or lean body mass between groups were not statistically significant. A significant negative correlation was found between REE (kcal/kg/day) and weight-for-age (p = .04), and a trend with height-for-age Z-score (p = .07). Mean energy intake was not significantly different between groups. This study suggests that lean and fat mass are proportionately reduced in HIV-positive children with growth retardation. Further studies are necessary to delineate the relationship between energy balance and growth in children with HIV infection.

At issue: is household crowding a risk factor for schizophrenia and bipolar disorder?

Five studies have reported that being born or raised in an urban area is a risk factor for developing psychosis later in life. The authors hypothesize that increased exposure to infectious agents through household crowding might account for this association.

Serum and plasma markers of nutritional status in children infected with the human immunodeficiency virus

OBJECTIVE

To determine whether reduced serum or plasma protein and micronutrient levels are common in children infected with the human immunodeficiency virus (HIV) and whether these levels are different in children with growth retardation compared to those with normal growth.

SUBJECTS

Children were separated into three groups: (a) HIV-infected with growth retardation (HIV + Gr); (b) HIV-infected with normal growth (HIV+); (c) HIV-uninfected with normal growth (HIV-). All children were afebrile and free of acute infection at the time of study. During a 24-hour stay in the Pediatric Clinical Research Unit, blood was drawn for analysis of total protein, albumin, zinc, selenium, and vitamin A levels; growth measurements were obtained; and dietary intake was assessed by 24-hour weighed food intake and 24-hour dietary recall.

STATISTICAL ANALYSIS

Mean differences between groups were assessed by analysis of variance, and differences in the frequency of nutrient deficiency were determined by chi 2 analysis.

RESULTS

Thirty-eight children between 2 and 11 years of age were studied: 10 HIV + Gr, 18 HIV+, and 10 HIV-. No statistically significantly differences were noted in mean levels of albumin, prealbumin, zinc, and selenium. Mean serum level of vitamin A was significantly higher in the HIV + Gr group than in the other two groups. There were no significant differences between groups in the frequency of deficiency for any nutrient studied. Mean energy and nutrient intake was similar among groups.

APPLICATIONS/CONCLUSIONS

Abnormal serum or plasma protein or micronutrient levels were uncommon in this cohort of HIV-infected children, even in children with growth retardation. Routine monitoring of the level of proteins and micronutrients studied is unnecessary in the absence of specific clinical indicators of deficiency.

Seasonality of births in schizophrenia and bipolar disorder: a review of the literature

More than 250 studies, covering 29 Northern and five Southern Hemisphere countries, have been published on the birth seasonality of individuals who develop schizophrenia and/or bipolar disorder. Despite methodological problems, the studies are remarkably consistent in showing a 5-8% winter-spring excess of births for both schizophrenia and mania/bipolar disorder. This seasonal birth excess is also found in schizoaffective disorder (December-March), major depression (March-May), and autism (March) but not in other psychiatric conditions with the possible exceptions of eating disorders and antisocial personality disorder. The seasonal birth pattern also may shift over time. Attempts to correlate the seasonal birth excess with specific features of schizophrenia suggest that winter-spring births are probably related to urban births and to a negative family history. Possible correlations include lesser severity of illness and neurophysiological measures. There appears to be no correlation with gender, social class, race, measurable pregnancy and birth complications, clinical subtypes, or neurological, neuropsychological, or neuroimaging measures. Virtually no correlation studies have been done for bipolar disorder. Regarding the cause of the birth seasonality, statistical artifact and parental procreational habits are unlikely explanations. Seasonal effects of genes, subtle pregnancy and birth complications, light and internal chemistry, toxins, nutrition, temperature/weather, and infectious agents or a combination of these are all viable possibilities.

Multivariate analysis of RNA levels from postmortem human brains as measured by three different methods of RT-PCR. Stanley Neuropathology Consortium

The analysis of RNA from postmortem human brain tissue by reverse transcription-polymerase chain reaction (RT-PCR) provides a practical method to measure both normal and abnormal brain gene expression. A major limitation in using human material is that yields can vary dramatically from individual to individual, making comparisons between samples difficult. In this report, we study the association of pH and several pre- and postmortem factors on the RNA yields from 89 postmortem human occipital cortices. Glyceraldehyde phosphate dehydrogenase (GAPdH) mRNA levels were measured by RT-PCR. A major variant in this method is the priming used in the reverse transcription reaction. Three different methods of reverse transcription were performed and the resultant levels of products compared against the pre- and postmortem factors and pH. The levels of GAPdH correlated significantly to pH and pH itself to the rapidity of death (RoD) (agonal state) indicating that premortem factors may play the greatest role in determining postmortem RNA levels. The three methods of priming showed different sensitivities, most notably that oligo dT priming alone is vulnerable to long freezer intervals (FI). We conclude that premortem factors are the major affectors of RNA levels variations and that the polyA tail region of the molecule appears to be adversely affected by extended freezer storage.

Metabolites of the antipsychotic agent clozapine inhibit the replication of human immunodeficiency virus type 1

Schizophrenia is a serious and often debilitating neuropsychiatric disease of worldwide importance. Current therapy relies on the use of typical antipsychotic medications, which specifically inhibit binding of ligand at the D2 dopamine receptor, and atypical medications which display little activity for this receptor interaction. While atypical antipsychotic agents have been shown to variably inhibit other neuroreceptor-ligand interactions, the exact mechanisms for the therapeutic efficacy of these medications have not been completely defined. Clozapine, an atypical antipsychotic, and nine of its metabolites were studied in vitro for possible antiviral activity against a model of a human neurotropic virus, human immunodeficiency virus type 1 (HIV-1). In an assay for inhibition of virus-induced cytopathic effect (CPE) two metabolites demonstrated antiviral activity (ID50 = 37-85 micrograms/ml) (119-289 microM), while other atypical or novel antipsychotics as well as typical medications had no effect. Based on an ELISA, four chemically similar metabolites inhibited the production of p24, the major internal antigen of HIV (ID50 = 11.6-15.7 micrograms/ml) (38-51 microM). These data suggest that the therapeutic efficacy of some antipsychotics may be due in part to an ability to inhibit viral replication. Antiviral agents may prove to be effective adjuncts in the treatment of schizophrenia.

Workshop on schizophrenia

On November 29-30, 1995, the National Academy of Sciences and the Institute of Medicine brought together experts in schizophrenia and specialists in other areas of the biological sciences in a workshop aimed at promoting the application of the latest biological information to this clinical problem. The workshop paid particular attention to evidence of pathology in the brains of people with schizophrenia, and to the possibility that this reflects an abnormality in brain development that eventually leads to the appearance of symptoms. The participants were impressed with the complexity of the problem, and felt that multiple approaches would be required to understand this disease. They recommended that a major focus should be on the search for predisposing genes, but that there should be parallel research in many other areas.