Nonschizophrenic Control Subjects Research Articles

The schizophrenia and Toxoplasma gondii connection: Infectious, immune or both?

Recent research has suggested a possible link between toxoplasmic agents and schizophrenia. We aimed to assess this by measuring Toxoplasma gondii-associated antibodies in schizophrenia patients and controls We used a commercially available enzyme-linked immunosorbent assay (ELISA) kit to measure the level of immunoglobulin G (IgG) and IgM antibodies in serum samples from schizophrenia patients (n=40) and from a group of non-schizophrenic control subjects (n=37) Among schizophrenic patients, 16 (40%) showed IgG seropositivity and two (5%) showed IgM seropositivity. Among the control group, five (13.5%) were found have IgG seropositivity and one (2.7%) showed IgM seropositivity. In our study we found that IgG T gondii antibodies were significantly higher in schizophrenia patients compared with controls This study supports the theory that toxoplasmic agents may have a role in the aetiology of schizophrenia.

Single-voxel proton magnetic resonance spectroscopy of the pons and cerebellum in patients with schizophrenia: a preliminary study

Magnetic resonance spectroscopy (MRS) is a non-invasive functional imaging technique that can measure various brain tissue metabolites such as N-acetylaspartate (NAA), choline (Cho), creatine-phosphocreatine (Cr), myo-inositol (mI) and other metabolites. Morphological studies have indicated the pons and cerebellum as possible sites of abnormal functioning in schizophrenic patients. This study examines schizophrenic patients for the presence of abnormalities in proton MRS ( 1H-MRS) measured metabolites in two regions of the posterior fossa. Twelve schizophrenic patients and eight non-schizophrenic control subjects were studied by measuring the ratios of NAA/Cr, Cho/Cr and mI/Cr from 1H-spectra obtained from the pons and right or left cerebellum using an integrated MRI/MRS protocol. Spectra were obtained from a voxel in the pons and voxels from the left and/or right lateral cerebellum. Data were analyzed in the absorption mode and fitted to Lorentzian lineshapes using a Marquart algorithm. Significantly lower NAA/Cr ratios were found in the pons of schizophrenic patients than in the control subjects, but not in the cerebellum. This study is the first to measure brain tissue metabolites using 1H-MRS in the pons and cerebellum of schizophrenic patients. Significant alterations of 1H-MRS metabolites may suggest the involvement of the posterior fossa as a part of the pathological substrate underlying schizophrenia.

Detection of retroviral serum antibodies in schizophrenics

Olfactory sensitivity to two odorants, iso-amyl acetate and androstercme, was assessed in 19 schizophrenic patients and 10 nonschizophrenic control subjects (5 healthy subjects, 4 0 C D patients, and 1 MDD patient). Tests were performed during a drug-free period and 3 weeks after initiation of neuroleptic drug therapy. There were two main findings: 1 ) a significantly reduced olfactory sensitivity to iso-amyl acetate in drug-free schizophrenic patients as compared to nonschizophrenic controls; 2) a significant reduction in olfactory sensitivity induced by commonly used neuroleptic treatment. Is the reduced olfactory sensitivity due to previous long-term exposure to neuroleptic drags, or is it due to an inborn defect associated with the pathophysiology of the disorder? Further studies with drag-naive schizophrenic patients are needed to elucidate this question.

Hippocampal Pyramidal Cell Disarray in Schizophrenia as a Bilateral Phenomenon

In a continuing quantitative study of hippocampal cell orientation in schizophrenic subjects and nonschizophrenic control subjects, a pattern of right hemispheric cell disorganization in schizophrenic subjects, as robust as that previously described in the left hemisphere, was shown. The study was based on tissue from 11 schizophrenic and seven approximately age-matched control subjects from a Veterans Administration Medical Center. Using a new measuring technique that proved complementary and superior to the method formerly used, we determined the axes of orientation for approximately 10,800 neurons. A significant difference in cell disorganization was found between schizophrenic and control subjects. From separate analyses of the interface zones among the various hippocampal cell sectors, this difference was found to be significant at the interfaces between cornu ammonis zones 1 and 2 and zones 2 and 3. Analysis of the pattern of disorganization numbers suggests a bimodal distribution in which the cell orientation values of one group of schizophrenic subjects overlap those of the nonschizophrenic control group, while the cell orientation values of a second group significantly exceed those of the control population. Although some recent studies have suggested that schizophrenia may be related exclusively to the left hemisphere, the results of this study indicate that schizophrenia-related structural changes involve the right hemisphere as well. Thus, schizophrenia may be a bilateral rather than unilateral disorder.

Autoantibodies against brain septal region antigens specific to unmedicated schizophrenia?

Heath et al. (1989) reported that serum from 96% of unmedicated schizophrenic patients contained IgG autoantibodies specific for the septal region of rhesus monkey brain, compared with 0% of nonschizophrenic control subjects and 6% of schizophrenic patients who were on neuroleptic medication. Using the same technique of crossed immunoelectrophoresis, we have tried to replicate this finding. In contrast to the original report, we observed “positive” precipitin arcs with IgG concentrates from all 14 serum samples tested. The failure of immunoelectrophoretic methods to provide convincing evidence of pathogenic autoantibodies in schizophrenia in no way detracts from the hypothesis that autoimmune processes are involved in some forms of schizophrenia. Such methods have not proved useful in established autoimmune diseases such as Graves' disease and myasthenia gravis in which the pathogenic autoantibodies against cell-surface receptors can only be detected by assays which measure functional interactions with such receptors.

Axonal counts of the corpus callosum of schizophrenic patients

This study attempted to identify microscopic correlates to the structural abnormalities reported in the corpus callosum of schizophrenic patients. Sections of the genu, body, and splenium of the corpus callosum were taken from formalin-fixed brains of deceased patients with schizophrenia and nonschizophrenic control subjects. Photomicrographs of stained tissue were projected, and nerve fibers were counted. There were no significant differences (p greater than 0.4) in axonal counts between schizophrenic and control patients for any of the sites sampled. Our results suggest that morphometric abnormalities of the corpus callosum of schizophrenic patients, if present, are not the consequence of a primary process within this structure.

Antiseptal brain antibody in IgG of schizophrenic patients

On the hypothesis that schizophrenia is an immunological disorder in which antibody is produced against a unique antigen sequestered principally or exclusively in the septal region of the brain, we used crossed-immunoelectrophoresis (CIE) to evaluate reactivity of a gamma G immunoglobulin (IgG) fraction from serum of schizophrenic patients and nonschizophrenic control subjects with homogenates of tissues of septal region, hippocampus, vermal cerebellum, frontal cortex, and liver of rhesus monkeys. When IgG fractions of unmedicated schizophrenic patients and schizophrenic patients who had received neuroleptic medication for less than 24 hr were tested against septal region homogenate, a precipitin arc was identified, indicating a positive result, with more than 95% of the fractions. In contrast, IgG fractions of schizophrenic patients who had received neuroleptic medication for more than 24 hr were rarely positive. When schizophrenic fractions that tested positive against septal region homogenate were tested against homogenates of the other tissues, they were negative. Fractions of all nonschizophrenic control subjects were negative against all homogenates.

Asymmetries in hemispheric control of attention in schizophrenia.

Investigators have long suggested that schizophrenia might be related to an impairment in the regulation of attention. In this report, the performance of schizophrenic patients was compared with nonschizophrenic control subjects in their ability to direct visual attention. In the first experiment, patients were distinguished from controls by a slower response to a target in the right visual field than to a target in the left visual field when attention was not first directed to the target location. In the second experiment, patients were distinguished from controls by a stronger bias in favor of symbolic information over language information about spatial direction. In both experiments, the patients demonstrated deficits in attention similar to patients from previous studies who had unilateral lesions of the left hemisphere. The identification of performance abnormalities using tasks that are simple, have dissectable cognitive components, have been related to discrete neural systems, and control for nonspecific variables provide the basis for constructing reasonable hypotheses about the cognitive psychology and functional neuroanatomy of schizophrenia.

The effects of labeling: blind and nonblind ratings of social skills in schizophrenic and nonschizophrenic control subjects.

The effects of labeling: blind and nonblind ratings of social skills in schizophrenic and nonschizophrenic control subjects.

Absence of activation in frontal structures during psychological testing of chronic schizophrenics.

The distribution of activity in the dominant hemisphere was measured with the regional cerebral blood flow (rCBF) technique in 27 chronic schizophrenics and 15 non-schizophrenic control subjects (alcoholics) at rest and during phychological testing. In the non-schizophrenics, an increase of rCBF was observed during the test in frontal regions. In the chronic schizophrenics, on the other hand, no or only a very limited increase was recorded. In postcentral structures the flow response during the testing was, by and large, equal in the psychotics and the controls. The findings support the hypothesis advanced previously by the authors that in chronic schizophrenia there is defective transmission in the mediothalamic frontocortical projection bundle. This defect also appears responsible for the abnormally low resting flow (activity) in the dominant hemisphere in chronic schizophrenia which we have described previously.

A FURTHER STUDY OF THE EFFECTS OF SERUM FROM SCHIZOPHRENICS ON EVOKED CORTICAL POTENTIALS IN THE RAT.

In 1963, one of us reported that serum from schizophrenic patients, applied topically to the cerebral cortex of the rat, produced a large increase in the amplitude of the electrical response evoked in the cortex by cutaneous stimulation (German, 1963). This effect was not observed when serum from non-schizophrenic control subjects was used.

Further observations on electrophysiological sleep patterns in schizophrenia

Electrophysiological studies of sleep patterns in a group of eighteen actively ill schizophrenic patients and ten non-schizophrenic control subjects yielded the following results: the schizophrenic patients required a significantly longer time to fall asleep and showed greater variability in the amount of sleep occurring prior to the onset of first dream than did the control subjects. Patients classified as hallucinating showed significantly higher density of eye-movement activity during their dream periods than non-hallucinating schizophrenic patients.