Baseline measures of cerebral glutamate and GABA levels in individuals at ultrahigh risk for psychosis: Implications for clinical outcome after 12 months

Background.

Cerebral glutamate and gamma-aminobutyric acid (GABA) levels might predict clinical outcome in individuals at ultrahigh risk (UHR) for psychosis but have previously primarily been investigated in smaller cohorts. We aimed to study whether baseline levels of glutamate and GABA in anterior cingulate cortex (ACC) and glutamate in thalamus could predict remission status and whether baseline metabolites differed in the remission versus the nonremission group. We also investigated the relationship between baseline metabolite levels and severity of clinical symptoms, functional outcome, and cognitive deficits at follow-up.

Methods.

About 124 UHR individuals were recruited at baseline. In this, 74 UHR individuals were clinically and cognitively assessed after 12 months, while remission status was available for 81 (25 remission/56 nonremission). Glutamate and GABA levels were assessed at baseline using 3 T proton magnetic resonance spectroscopy. Psychopathology, symptom severity, and remission were assessed with the Comprehensive Assessment of At-Risk Mental States and Clinical Global Impression and functional outcome with the Social and Occupational Functioning Assessment Scale. Cognitive function was estimated with the Cambridge Neuropsychological Test Automated Battery.

Results.

There were no differences between baseline glutamate and GABA levels in subjects in the nonremission group compared with the remission group, and baseline metabolites could not predict remission status. However, higher baseline levels of GABA in ACC were associated with clinical global improvement (r = −0.34, N = 51, p = 0.01) in an explorative analysis.

Conclusions.

The variety in findings across studies suggests a probable multifactorial influence on clinical outcome in UHR individuals. Future studies should combine multimodal approaches to attempt prediction of long-term outcome.

White matter maturation during 12 months in individuals at ultra-high-risk for psychosis

OBJECTIVE

The neurodevelopmental hypothesis of psychosis suggests that disrupted white matter (WM) maturation underlies disease onset. In this longitudinal study, we investigated WM connectivity and compared WM changes between individuals at ultra-high-risk for psychosis (UHR) and healthy controls (HCs).

METHOD

Thirty UHR individuals and 23 HCs underwent MR diffusion tensor imaging before and after 12 months of non-manualized standard care. Positive and negative symptoms and level of functioning were assessed. Tract-based spatial statistics were employed.

RESULTS

During 12 months, none of the UHR individuals transitioned to psychosis. Both UHR individuals and HCs increased significantly in fractional anisotropy (FA). UHR individuals showed significant FA increases predominantly in the left superior longitudinal fasciculus (SLF) (P = 0.01), and HCs showed significant FA increases in the left uncinate fasciculus (P = 0.03). Within UHR individuals, a significant positive correlation between FA change and age was observed predominantly in the left SLF (P = 0.02). Within HCs, no significant correlation between FA change and age was observed. No significant correlations between baseline FA and clinical outcomes were observed; however, FA changes were significantly positively correlated to changes in negative symptoms (P = 0.04).

CONCLUSION

As normal brain maturation occurs in a posterior to frontal direction, our findings could suggest disturbed WM maturation in UHR individuals.

Patterns of white matter microstructure in individuals at ultra-high-risk for psychosis: associations to level of functioning and clinical symptoms

BACKGROUND

Individuals at ultra-high-risk (UHR) for psychosis present with emerging symptoms and decline in functioning. Previous univariate analyses have indicated widespread white matter (WM) aberrations in multiple brain regions in UHR individuals and patients with schizophrenia. Using multivariate statistics, we investigated whole brain WM microstructure and associations between WM, clinical symptoms, and level of functioning in UHR individuals.

METHODS

Forty-five UHR individuals and 45 matched healthy controls (HCs) underwent magnetic resonance diffusion tensor imaging (DTI) at 3 Tesla. UHR individuals were assessed with the Comprehensive Assessment of At-Risk Mental States, Scale for the Assessment of Negative Symptoms, and Social and Occupational Functioning Assessment Scale. Partial least-squares correlation analysis (PLSC) was used as statistical method.

RESULTS

PLSC group comparisons revealed one significant latent variable (LV) accounting for 52% of the cross-block covariance. This LV indicated a pattern of lower fractional anisotropy (FA), axial diffusivity (AD), and mode of anisotropy (MO) concomitant with higher radial diffusivity (RD) in widespread brain regions in UHR individuals compared with HCs. Within UHR individuals, PLSC revealed five significant LVs associated with symptoms and level of functioning. The first LV accounted for 31% of the cross-block covariance and indicated a pattern where higher symptom score and lower level of functioning correlated to lower FA, AD, MO, and higher RD.

CONCLUSIONS

UHR individuals demonstrate complex brain patterns of WM abnormalities. Despite the subtle psychopathology of UHR individuals, aberrations in WM appear associated with positive and negative symptoms as well as level of functioning.

Negative symptoms mediate the relationship between neurocognition and function in individuals at ultrahigh risk for psychosis

OBJECTIVE

Neurocognition is known to impact functioning in individuals at ultrahigh risk (UHR) for psychosis, but studies investigating potential mediators of this relationship are scarce. Building on evidence from schizophrenia spectrum disorders, the study tested whether negative symptoms and social skills act as mediators between neurocognition and functional outcome in UHR individuals.

METHODS

Ultrahigh risk participants (N = 84) underwent neurocognitive testing using the Brief Assessment of Cognition in Schizophrenia. Social skills and negative symptoms were assessed using the High-Risk Social Challenge task and the Scale for the Assessment of Negative Symptoms respectively. Four instruments were used to assess overall functioning, and one instrument assessed quality of life encompassing social functioning.

RESULTS

The cross-sectional analyses revealed that neurocognition was related to the measures of functioning. Negative symptoms mediated the relationship between neurocognition and four of the five measures of functioning. We did not find social skills to mediate between neurocognition and functioning.

CONCLUSION

Negative symptoms appear to mediate the relationship between neurocognition and functional outcome in UHR individuals, but the finding needs to be confirmed and extended to longitudinal studies. This underscores the importance of focusing on both neurocognition and negative symptoms when aiming at improving the functional outcome of UHR individuals.

Ewing's sarcoma. Cytologic features in fine needle aspirates in two cases

The cytologic findings of two cases of Ewing's sarcoma in fine needle aspiration biopsies are presented in relation to the subsequent histologic findings. The malignant cells were arranged in monocellular layers, pseudorosettes and in perivascular palisades in a fibrillar background. The nuclei were monomorphous with small nucleoli and finely granular chromatin. These features may be helpful in distinguishing this tumor from other small-cell neoplasms; the differential diagnosis between Ewing's sarcoma and such tumors is discussed.

Immunofluorescent localisation of cathepsin D in trophoblastic cells in tissue culture

Cathepsin D was localised by immunofluorescence within four different types of cells derived from human trophoblast in monolayer culture. Cells were stained with freshly reduced Fab' fragments of sheep anti-(human cathepsin D) antiserum followed by FITC conjugate of pig anti-(sheep Fab') Fab' fragments. The green fluorescence seen in cytoplasmic droplets were characteristic of the appearance of lysosomes in other cells.

Pinocytosis and intracellular digestion of 125I-labelled haemoglobin by trophoblastic cells in tissue culture in the presence and absence of serum

One aspect of human placental function which has not hitherto been studied is the ability of the placenta to digest proteins intracellularly and use the products of hydrolysis to supply its own and foetall complement of hydrolytic enzymes, including the acid proteases cathepsin C and D. We have used trophoblast cells in monolayer tissue culture as a model for the study of endocytosis and intracellular digestion of 125I-haemoglobin. The normal use of serum in tissue culture medium has shown up differences from the pattern observed with other phagocytic cells such as macrophages, in that serum allows endocytosis but prevents intracellular digestion of 125I-haemoglobin. Replacement of serum by lactalbumin hydrolysate enables both endocytosis and intracellular digestion of 125I-haemoglobin to occur as in other phagocytic cells. Digestion is followed by release into the medium of acid-soluble, lower-molecular-weight compounds. The reasons for this major difference between trophoblast and other cells are discussed in the light of our results and their possible relevance to placental function.

Characterization of a neutral protease from lysosomes of rabbit polymorphonuclear leucocytes

1. The subcellular distribution has been investigated of a protease from rabbit polymorphonuclear leucocytes, obtained from peritoneal exudates. The enzyme, optimally active between pH7.0 and 7.5, hydrolyses histone but not haemoglobin, sediments almost exclusively with a granule fraction rich in other lysosomal enzymes, and is latent until the granules are disrupted by various means. 2. Enzymic analysis of specific and azurophilic granules separated by zonal centrifugation showed that neutral protease activity was confined to fractions rich in enzymes characteristic of azurophile granules. 3. Recovery of neutral protease activity from subcellular fractions was several times greater than that found in whole cells. This finding was explained by the presence of a potent inhibitor of the enzyme activity in the cytoplasm. 4. The effect of the inhibitor was reversed by increasing ionic strength (up to 2.5m-potassium chloride) and by polyanions such as heparin and dextran sulphate, but not by an uncharged polymer, dextran. 5. The enzyme was also inhibited, to a lesser extent, by 1-chloro-4-phenyl-3-l-toluene-p-sulphonamidobutan-2-one, soya-bean trypsin inhibitor and in-aminohexanoate (in-aminocaproate). 6. The granule fractions failed to hydrolyse artificial substrates for trypsin and chymotrypsin. 7. Partial separation of the enzyme was achieved by Sephadex gel filtration at high ionic strength and by isoelectric focusing. The partially separated, activated enzyme showed an approximately 300-fold increase in specific activity over that in whole cells.

The irrigation smear--a new cytodiagnostic technique for the detection of cancer of the uterine cervix

Using the Davis cytopipette, cytologic smears were prepared from 2014 patients; 1367 of these specimens were obtained by the patients themselves. The series included 57 cases of carcinoma or atypia of the cervix, and 50 (88%) of these cases were found to have abnormal cells in the irrigation smear.Cytopipette samples were obtained by a nurse from 647 Eskimos, but cell preservation in this group was not satisfactory because of a delay of several weeks in preparing the smears. Accurate results depend also on specific training of the personnel reading the smears because fewer cells may be present in these smears than in cervical scrape smears.The irrigation smear is recommended as a reasonably accurate method of screening women for cancer of the cervix if they are not being examined regularly by the cervical scrape method. Hospital admissions of females may be a fruitful source of such cases.