Computed tomography scans and negative symptoms in schizophrenia: chronic schizophrenics with negative symptoms and nonenlarged lateral ventricles

Computed tomography scans of 31 chronic schizophrenics with negative symptoms and 31 age-matched normal volunteers were assessed for ventricular size, cortical atrophies, third ventricle diameter, and cerebellar atrophies. No significant differences were found in the size of the lateral ventricles or third ventricles between the chronic schizophrenics and the controls. The frontal horns in patients did show a tendency toward increased size compared with controls. Sulci width showed significant differences between patients and controls. The clinical variables, except for the memory test, did not correlate with any brain morphology. A meta-analysis was performed on 17 studies that used the planimetric method in order to evaluate the relationships between the size of the lateral ventricles in patients and their respective controls. We found significant differences between the group of studies using normal controls and the group using medical controls.     

The energy metabolism in the right and left ventricles of human donor hearts across transplantation.

OBJECTIVE: Brain death appears to predominantly affect the right ventricle (RV) and right ventricular failure is a common complication of clinical cardiac transplantation. It is not clear to what extent myocardial energy stores are affected in the operative sequence. We aimed to describe the time-dependent variation in high energy phosphate (HEP) metabolism of the two ventricles, and the relationship with endothelial activation and postoperative functional recovery. METHODS: Fifty-two human donors had serial biopsies from the RV and the left ventricle (LV) at (1) initial evaluation, (2) after haemodynamic optimisation, (3) end of cold ischaemia, (4) end of warm ischaemia, (5) reperfusion, and (6) at 1 week postoperatively. HEP was measured by chemiluminescence in biopsies 1-5 and adhesion molecules (P-selectin, E-selectin, VCAM-1) and thrombomodulin were analysed by immunohistochemistry in biopsies 5-6. Seventeen donors and five recipients had RV intraoperative pressure-volume recordings by a conductance catheter. Six patients served as live controls. RESULTS: Brain death did not affect HEP metabolism quantitatively. There was no difference between the RV and LV at any time point, but significant time-dependent changes were observed. The RV was prone to HEP depletion at retrieval, with ATP/ADP falling from 3.89 to 3.13, but recovered during cold ischaemia. During warm ischaemia the ATP/ADP ratio fell by approximately 50%, from 5.48 for the RV and 4.26 for the LV, with partial recovery at reperfusion (P<0.005). Hearts with impaired function in the recipient showed marked variations in HEP levels at reperfusion, and those organs with RV dysfunction failed to replenish their energy stores. However, these organs were not different from normally functioning allografts in terms of endothelial activation and clinical risk factors. There was poor correlation between pressure-volume and HEP data in either donor or recipient studies. Hearts followed-up with HEP and pressure-volume studies showed improvement in the recipient, despite functioning against a higher pulmonary vascular resistance. CONCLUSIONS: HEP are preserved over a wide range of contractile performance in the donor heart, with no metabolic difference between the two ventricles. No correlation with endothelial activation was seen either. Preservation efforts should be directed to the vulnerable periods of implantation and reperfusion.     

Glycosylation differences between the normal and pathogenic prion protein isoforms

Prion protein consists of an ensemble of glycosylated variants or glycoforms. The enzymes that direct oligosaccharide processing, and hence control the glycan profile for any given glycoprotein, are often exquisitely sensitive to other events taking place within the cell in which the glycoprotein is expressed. Alterations in the populations of sugars attached to proteins can reflect changes caused, for example, by developmental processes or by disease. Here we report that normal (PrP(C)) and pathogenic (PrP(Sc)) prion proteins (PrP) from Syrian hamsters contain the same set of at least 52 bi-, tri-, and tetraantennary N-linked oligosaccharides, although the relative proportions of individual glycans differ. This conservation of structure suggests that the conversion of PrP(C) into PrP(Sc) is not confined to a subset of PrPs that contain specific sugars. Compared with PrP(C), PrP(Sc) contains decreased levels of glycans with bisecting GlcNAc residues and increased levels of tri- and tetraantennary sugars. This change is consistent with a decrease in the activity of N-acetylglucosaminyltransferase III (GnTIII) toward PrP(C) in cells where PrP(Sc) is formed and argues that, in at least some cells forming PrP(Sc), the glycosylation machinery has been perturbed. The reduction in GnTIII activity is intriguing both with respect to the pathogenesis of the prion disease and the replication pathway for prions.     

Electrical taste thresholds established on the medial tongue using two sizes of electrodes

OBJECTIVES/HYPOTHESIS: The present study determined whether a 125 mm electrode would produce lower and more reliable electrical taste thresholds than a 25 mm electrode when measurement occurred in a medial tongue region relatively sparse in taste bud numbers. We hypothesized this would be the case and that the obtained threshold values would be higher than those previously reported for anterior and lateral tongue regions. STUDY DESIGN AND METHODS: Sixteen college-age subjects were tested twice, once using the 25 mm electrode and once using the 125 mm electrode on each of two sessions separated by 2 to 16 days. The order of presentation of the sessions was counterbalanced across subjects. Measurement was confined to the medial tongue, 0.7 cm lateral to the median furrow. RESULTS: As hypothesized, the larger electrode resulted in lower and more reliable threshold values than the smaller electrode (respective median threshold values = 20.06 microA & 33.59 microA, P = .001; respective test-retest rs = 0.78 [P < .001] and 0.46 [P < .05]). Also as hypothesized, the threshold values were higher (i.e., sensitivity lower) than previously reported for anterior and lateral tongue regions. CONCLUSIONS: The magnitude and reliability of electrical taste thresholds depends on the tongue region examined and the size of the electrodes used. These results suggest that relatively large electrodes should be considered for electrogustometric threshold testing, particularly when lingual regions not highly populated with taste buds are evaluated.