Memory encoding and retrieval in the aging brain.

Decline in episodic memory, the encoding and retrieval of autobiographical events, is a hallmark of normal cognitive aging. Although the primary causes of this decline remain elusive, event-related brain potential (ERP) studies have contributed to an understanding of age-related episodic memory failure. These data reveal that, although the retrieval-based episodic memory (EM) effect does not differ dramatically between young and older adults, the acquisition-related data suggest a decline in episodic encoding (i.e., semantic elaboration) with increasing age. We conclude that, at the current state of knowledge, encoding deficiencies are more important than retrieval deficits in understanding the causes of episodic memory decline in the older adult.     

Functional magnetic resonance imaging in schizophrenia: cortical response to motor stimulation

Previous functional magnetic resonance imaging (fMRI) studies suggest that motor system abnormalities are present in schizophrenia. However, these studies have often produced conflicting or ambiguous findings. The purpose of this study was to ascertain whether activation differences could be identified in stable schizophrenic patients on the basis of BOLD measures in two motor regions, the primary motor cortex, Brodmann area 4 (BA4) and the premotor and supplementary motor area, Brodmann area 6 (BA6). Twenty-one schizophrenic patients and 21 healthy control subjects were studied with BOLD fMRI methods during a sequential finger tapping task. Statistical parametric maps were generated for each subject, and anatomic regions were automatically defined using an anatomic atlas. Compared with controls, the schizophrenic patients showed a significant reduction in contralateral activation for both BA4 and BA6 (P<0.001), and in ipsilateral activation in BA4 (P=0.007) and BA6 (P=0.002). In healthy controls, the coactivation in the ipsilateral cortex is reduced in comparison with the contralateral cortex for right and left handed tasks. In BA4, this reduction is significant for right (P=0.007) and left (P=0.003) finger tapping. Similar results were obtained for BA6. Further analyses are necessary to evaluate the activation in other motor system regions.     

Alternating copolymerization of carbon dioxide and propylene oxide in the presence of organometallic catalysts

Carbon dioxide and propylene oxide (PO) were copolymerized using diethylzinc in addition with benzenedi- and triols, aliphatic diols and triols, and aminophenols as catalyst systems. A large amount of CO₂/PO alternating copolymer, {poly(propylene carbonate), poly(oxycarbonyloxypropylene), of high molecular weight was obtained using the homogeneous (C₂H₅)₂Zn/pyrogallol (2:1 by mole) system ( 1 ). The (C₂H₅)₂Zn/o-aminophenol system ( 2 ) (also homogeneous) appeared to be much less active in the copolymerization of CO₂ with PO than the former one. From the other studied systems, that appeared to be heterogeneous, (C₂H₅)₂Zn/resorcinol (1:1 by mole) was the most active one, but less active than the system 1 . Further, the copolymerization of CO₂ and PO was studied in the presence of the (C₂H₅)₂Zn/resorcinol (1:1 by mole) system at various temperatures and in reaction media of different basicity. On the basis of the obtained results of the copolymerization of CO₂ with PO and of measurements of the quantity of ethane evolved in the reactions between the catalytic systems' components, structures of several catalysts, particularly homogeneous ones, are suggested and some aspects of the copolymerization mechanism are discussed.     

Fünf neue Menacanthus-Arten aus mitteleuropäischen Singvögeln

Zusammenfassung Aus mitteleuropäischen Singvögeln werden die folgenden neuen Menacanthus-Arten beschrieben: M. festivus nov. spec. von Fringilla coelebs, M. pius nov. spec. von Turdus merula, M. polonicus nov. spec. von Turdus pilaris, M. vistulanus nov. spec. von Sylvia borin und M. wipszyckii nov. spec. von Chloris chloris. Die Tatsache, daß das insgesamt aus mehreren Funden und besonders für M. pius nov. spec. aus zahlreichen Exemplaren bestehende, dieser Arbeit zugrunde liegende Untersuchungsmaterial fast ausschließlich Weibchen enthält, wird als Ausgangspunkt für eine Diskussion des Speziesbegriffs bei uniparentalen Mallophagenarten herangezogen. Zur Klärung dieser auch evolutionstheoretisch bemerkenswerten Problematik wird ein Forschungsprogramm für Menacanthus-Arten entwickelt.Mit 10 Textabbildungen     

Image processing techniques for noise removal, enhancement and segmentation of cartilage OCT images

Osteoarthritis, whose hallmark is the progressive loss of joint cartilage, is a major cause of morbidity worldwide. Recently, optical coherence tomography (OCT) has demonstrated considerable promise for the assessment of articular cartilage. Among the most important parameters to be assessed is cartilage width. However, detection of the bone cartilage interface is critical for the assessment of cartilage width. At present, the quantitative evaluations of cartilage thickness are being done using manual tracing of cartilage-bone borders. Since data is being obtained near video rate with OCT, automated identification of the bone-cartilage interface is critical. In order to automate the process of boundary detection on OCT images, there is a need for developing new image processing techniques. In this paper we describe the image processing techniques for speckle removal, image enhancement and segmentation of cartilage OCT images. In particular, this paper focuses on rabbit cartilage since this is an important animal model for testing both chondroprotective agents and cartilage repair techniques. In this study, a variety of techniques were examined. Ultimately, by combining an adaptive filtering technique with edge detection (vertical gradient, Sobel edge detection), cartilage edges can be detected. The procedure requires several steps and can be automated. Once the cartilage edges are outlined, the cartilage thickness can be measured.     

The striopallidal pathway is involved in antiparkinsonian-like effects of the blockade of group I metabotropic glutamate receptors in rats

The aim of the study was to examine the influence of the blockade of group I metabotropic glutamate receptors (mGluRs) on the haloperidol-induced catalepsy and proenkephalin mRNA expression in the rat striatum. Bilateral, intrastriatal injection of AIDA ((RS)-1-aminoindan-1,5-dicarboxylic acid, 3-15 microg/0.5 microl), a selective antagonist of group I mGluRs, inhibited catalepsy induced by haloperidol (0.5 mg/kg i.p.). Repeated intrastriatal AIDA administrations (3 x 15 microg/0.5 microl, 3 h apart) counteracted the haloperidol-induced (3 x 1.5 mg/kg s.c., 3 h apart) increase in the proenkephalin mRNA expression in that structure. The present study indicates that the blockade of the striatal group I mGluRs may inhibit parkinsonian akinesia by normalizing the function of the striopallidal pathway.     

Investigations on the catalytic systems diethylzinc/Di- and trihydroxybenzenes in the copolymerization of carbon dioxide with propylene oxide

Investigations on the reactions of diethylzinc ( 1 ) with resorcinol ( 2 ) and phloroglucinol ( 8 ) were carried out for different mole ratios of the reactants. It was found that the reaction of 1 with 2 at a mole ratio of 1:1 is a two step process. In the first step 1 reacts very rapidly with half of applied 2 yielding di(ethylzinc) resorcinolate ( 6 ), which then reacts slowly with the remaining amount of 2 . It was found that zinc 3-ethylzincoxyphenolate resorcinolate ( 5 ) formed in the second step is an active catalyst of the copolymerization reaction of carbon dioxide with propylene oxide. The reaction of 1 with 8 shows a similar course.     

Decreased activation of the anterior cingulate in bipolar patients: an fMRI study

BACKGROUND: Previous neuroimaging investigations of patients with bipolar disorder have reported abnormalities of the frontal subcortical network. The role of the anterior cingulate cortex (ACC) and the dorsolateral prefrontal cortex (DLPFC) in bipolar disorder are not clear, although both regions have been shown to be components of a neural network which plays a critical role in the completion of tasks requiring self-monitoring and inhibition, functions often noted to be altered in bipolar patients. fMRI studies have helped clarify the role of specific subdivisions of the ACC and the DLPFC during the performance of cognitive challenges, including the Stroop color word test. To date, studies that have examined ACC function in bipolar patients have not differentiated subregions within this area, nor have they examined changes in these subregions in relation with DLPFC activation. METHODS: To help clarify the specific roles of these regions in bipolar patients, we examined stable patients and control subjects during performance of the Stroop test using BOLD fMRI techniques. We hypothesized that bipolar patients would demonstrate reduced activation of two subdivisions of the ACC (AAA and VOA), as well as altered activation of the DLPFC, during the interference condition. RESULTS: Results indicate that relative to controls, bipolar patients demonstrated significantly reduced signal intensity within the right AAA subdivision (p=0.011), which accompanied an increase in the DLPFC (p=0.049) during the task. LIMITATIONS: The study sample was somewhat small (11 patients, 10 controls) which limits the generalizability of the study findings, however, the patient sample consisted of well-diagnosed, stable, chronic individuals with bipolar disorder and the sample size provided enough power to detect between-group differences. CONCLUSIONS: These findings suggest differential processing strategies of bipolar patients and support the theory of altered frontal systems in these patients during the performance of cognitive tasks.     

Influence of exposure mode on vinyl chloride action

Rats were subjected to 4 h continuous or intermittent exposure to vinyl chloride (VC) at different time-weighted average concentrations (15, 50, 150, 500 and 15,000 mg/m³). Hepatic non-protein sulfhydryl content (NPSH) and excretion of thiodiglycolic acid (TdGA) in urine were determined. VC at concentrations from 50 mg/m³ to 15,000 mg/m³ caused a dose-dependent depression of NPSH, but no difference in the magnitude of this depression induced by continuous or intermittent exposure at the same average concentration of VC was noted. At average concentrations of 50 mg/m³ and 150 mg/m³, the urinary excretion of TdGA under continuous exposure did not differ from that under intermittent exposure, whereas at VC concentrations of 500 mg/m³ and 15,000 mg/m³ it was higher following continuous exposure.     

CD45 Isoform Expression in Autoimmune Myasthenia Gravis

In myasthenia gravis (MG), humoral and cellular immune mechanisms are involved in the autoimmune pathogenesis. In this study, we investigated the role of the CD45 molecule in MG, having recently reported an association in multiple sclerosis. CD45, a protein-tyrosine phophatase receptor type C (PTPRC), is essential for both thymic selection and peripheral activation of T and B cells. Our aims were to determine (a) the prevalence of a functional mutation in the CD45 gene (exon 4 77C &#77 G; prevalence analysis), and (b) the distribution of memory (CD45RO+) and naïve (CD45RA+) T cells in the peripheral blood (subset analysis). T cells from 78 patients with generalised MG were stained with monoclonal antibodies against CD45RO, CD45RA, CD4 and CD8 and quantified by four-colour flow cytometry. The control panel for the prevalence analysis (a) consisted of 303 healthy individuals. (b) From those, 67 age- and sex-matched probands were randomly selected as controls for the subset analysis. Patients were stratified according to their MG onset age, thymic pathology and immunosuppressive treatment. Statistical analysis was performed by Fisher's exact test, asymptotic &#104 2 test, the two-sided Mann-Whitney test and Spearman's correlation coefficient. As a result, the 77C &#77 G mutation in exon 4 of the CD45 gene was found in 1 of 78 patients versus none of the 303 controls. Thus, no association was detected with this single nucleotide polymorphism in MG patients overall. Surprisingly, however, ratios of CD45RO+ to CD45RA+ T cells were lower among CD8+ T cells from patients with late-onset MG ( P =0.023). Thymoma patients also showed a similar trend among CD4+ and CD8+ T-cells, as expected. These differences were not related to immunosuppressive drug treatment or thymectomy (in the 67 informative patients). Since there is no other evidence for increased thymopoiesis in late-onset MG, we propose an altered subset balance in the circulation.