SCHIZOPHRENIA IN A WOMAN WITH TEMPORAL LOBE ARTERIO-VENOUS MALFORMATIONS: AN UNUSUAL CASE REPORT

Intracellular compartment-specific proteasome dysfunction in postmortem cortex in schizophrenia subjects

Protein homeostasis is an emerging component of schizophrenia (SZ) pathophysiology. Proteomic alterations in SZ are well-documented and changes in transcript expression are frequently not associated with changes in protein expression in SZ brain. The underlying mechanism driving these changes remains unknown, though altered expression of ubiquitin proteasome system (UPS) components have implicated protein degradation. Previous studies have been limited to protein and transcript expression, however, and do not directly test the function of the proteasome. To address this gap in knowledge, we measured enzymatic activity associated with the proteasome (chymotrypsin-, trypsin-, and caspase-like) in the superior temporal gyrus (STG) of 25 SZ and 25 comparison subjects using flourogenic substrates. As localization regulates which cellular processes the proteasome contributes to, we measured proteasome activity and subunit expression in fractions enriched for nucleus, cytosolic, and membrane compartments. SZ subjects had decreased trypsin-like activity in total homogenate. This finding was specific to the nucleus-enriched fraction and was not associated with changes in proteasome subunit expression. Interestingly, both chymotrypsin-like activity and protein expression of 19S RP subunits, which facilitate ubiquitin-dependent degradation, were decreased in the cytosol-enriched fraction of SZ subjects. Intracellular compartment-specific proteasome dysfunction implicates dysregulation of protein expression both through altered ubiquitin-dependent degradation of cytosolic proteins and regulation of protein synthesis due to degradation of transcription factors and transcription machinery in the nucleus. Together, these findings implicate proteasome dysfunction in SZ, which likely has a broad impact on the proteomic landscape and cellular function in the pathophysiology of this illness.

Results of computerised tomography during first admission for psychosis

A cohort of 168 psychotic patients underwent computerised tomography (CT) during their first admission. Cortical atrophy was present in 40% of patients. The frequency of atrophy increased with age, but did not differ between patients with schizophrenia, schizoaffective disorder, bipolar disorder or psychotic depression. Other CT findings of note were present in 6.6% of patients, and included four infarctions, three arachnoid cysts, and one each of venous angioma, colloid cyst, cavum vergae and post-traumatic changes. The frequency of CT findings other than atrophy was increased in the psychotic depression group. The findings support the proposal of the onset of psychosis being an indication for CT.

Organic delusions: phenomenology, anatomical correlations, and review

Organic delusions are common, but have received little systematic study. Review of the literature reveals that they occur most commonly in toxic-metabolic processes and in disorders affecting the limbic system and basal ganglia. A prospective study of 20 consecutive patients with organic delusions revealed four general types of false beliefs: simple persecutory delusions, complex persecutory delusions, grandiose delusions, and those associated with specific neurological defects (anosognosia, reduplicative paramnesia). Simple delusions responded best to treatment, and complex delusions were more resistent. Acting on delusional beliefs was not unusual, and treatment of the delusions was an important aspect of management of the patient.

Electrophysiological basis for a dichotomy in schizophrenia

The nature of schizophrenia has long been debated. The following review presents an overview of the electrophysiological basis for the traditional process/reactive or typical/atypical distinction in schizophrenia. Evidence for this dichotomy was drawn from cortical EEG studies, with and without pharmacological activation, and from depth electrode research. The Japanese research in this area is also included. Both corticograms and subcortical studies indicate that the two schizophrenic groups are identifiable subtypes. Corticograms indicated abnormality in atypical schizophrenics but not in typical schizophrenics. Subcortical studies found both groups to be neurologically involved but with abnormal electrical activity emanating from the deep areas of the frontal and temporal lobes of typical and atypical schizophrenics, respectively.