Mammalian LIN-7 PDZ proteins associate with beta-catenin at the cell-cell junctions of epithelia and neurons.

The heterotrimeric PDZ complex containing LIN-2, LIN-7 and LIN-10 is known to be involved in the organization of epithelial and neuronal junctions in Caenorhabditis elegans and mammals. We report here that mammalian LIN-7 PDZ proteins form a complex with cadherin and beta-catenin in epithelia and neurons. The association of LIN-7 with cadherin and beta-catenin is Ca(2+) dependent and is mediated by the direct binding of LIN-7 to the C-terminal PDZ target sequence of beta-catenin, as demonstrated by means of co-immunoprecipitation experiments and in vitro binding assays with the recombinant glutathione S-transferase:LIN-7A. The presence of beta-catenin at the junction is required in order to relocate LIN-7 from the cytosol to cadherin-mediated adhesions, thus indicating that LIN-7 junctional recruitment is beta-catenin dependent and that one functional role of the binding is to localize LIN-7. Moreover, when LIN-7 is present at the beta-catenin-containing junctions, it determines the accumulation of binding partners, thus suggesting the mechanism by which beta-catenin mediates the organization of the junctional domain.

The GLT-1 and GLAST glutamate transporters are expressed on morphologically distinct astrocytes and regulated by neuronal activity in primary hippocampal cocultures.

The GLT-1 and GLAST astroglial transporters are the glutamate transporters mainly involved in maintaining physiological extracellular glutamate concentrations. Defects in neurotransmitter glutamate transport may represent an important component of glutamate-induced neurodegenerative disorders (such as amyotrophic lateral sclerosis) and CNS insults (ischemia and epilepsy). We characterized the protein expression of GLT-1 and GLAST in primary astrocyte-neuron cocultures derived from rat hippocampal tissues during neuron differentiation/maturation. GLT-1 and GLAST are expressed by morphologically distinct glial fibrillary acidic protein-positive astrocytes, and their expression correlates with the status of neuron differentiation/maturation and activity. Up-regulation of the transporters paralleled the content of the synaptophysin synaptic vesicle marker p38, and down-regulation was a consequence of glutamate-induced neuronal death or the reduction of synaptic activity. Finally, soluble factors in neuronal-conditioned media prevented the down-regulation of the GLT-1 and GLAST proteins. Although other mechanisms may participate in regulating GLT-1 and GLAST in the CNS, our data indicate that soluble factors dependent on neuronal activity play a major regulating role in hippocampal cocultures.

[Treatment of depression with St. Johns wort in general practice]. / Behandlung von Depressionen mit Johanniskrautextrakt in der Allgemeinpraxis.

70-90% of depressive patients are treated by their own family doctors. Recognising and treating depression is an important daily problem for family doctors. The severity of the disorder decides whether non-pharmacological therapy or pharmacotherapy is preferable. The choice and dosage of an antidepressant is dictated by the severity and the symptomatology of the disorder as well as the expected adverse effects. Not least on account of their low rate of adverse effects, phytotherapeutic agents are enjoying growing popularity among patients and thus assure high compliance. The use of herbal preparations is useful, in particular for mild to moderate depression in young patients or patients with a reserved attitude toward "chemical drugs". Of all phytopharmaceuticals St.-John's wort has been most widely scientifically documented for the treatment of depression.

[Clinical efficacy and tolerance of the hypericum special extract LI 160 in depressive disorders--a drug monitoring study]. / Wirksamkeit und Verträglichkeit des Hypericum-Spezialextraktes LI 160 bei depressiven Verstimmungen--eine ambulante Anwendungsbeobachtung.

PATIENTS AND METHODS: 647 patients suffering from mild to moderate depression treated for 6 weeks with hypericum extract LI 160 (Jarsin 300), 1 tablet t.i.d. RESULTS: The condition of the patients improved in 75% (primary endpoint). The von Zerssen depression score decreased from 19.8-21.2 (95%-CI) at base-line to 8.1-9.3 at week 6 (p < 0.001). All symptoms were improved at week 3 and further at week 6. The condition improved somewhat slower in patients older than 65 years. The severity of the depression did not appear to have an effect on the outcome. Adverse events were reported by 17% of the patients (gastrointestinal 10%). These were mostly mild or moderate. Tolerance was rated in 89% as satisfactory or better.

PDZ-mediated interactions retain the epithelial GABA transporter on the basolateral surface of polarized epithelial cells.

The PDZ target motifs located in the C-terminal end of many receptors and ion channels mediate protein-protein interactions by binding to specific PDZ-containing proteins. These interactions are involved in the localization of surface proteins on specialized membrane domains of neuronal and epithelial cells. However, the molecular mechanism responsible for this PDZ protein-dependent polarized localization is still unclear. This study first demonstrated that the epithelial gamma-aminobutyric acid (GABA) transporter (BGT-1) contains a PDZ target motif that mediates the interaction with the PDZ protein LIN-7 in Madin-Darby canine kidney (MDCK) cells, and then investigated the role of this interaction in the basolateral localization of the transporter. It was found that although the transporters from which the PDZ target motif was deleted were still targeted to the basolateral surface, they were not retained but internalized in an endosomal recycling compartment. Furthermore, an interfering BGT peptide determined the intracellular relocation of the native transporter. These data indicate that interactions with PDZ proteins determine the polarized surface localization of target proteins by means of retention and not targeting mechanisms. PDZ proteins may, therefore, act as a sort of membrane protein sorting machinery which, by recognizing retention signals (the PDZ target sequences), prevents protein internalization.

Accuracy of diagnosis of subtle chest disease and subtle fractures with a teleradiology system.

OBJECTIVE: This study compared conventional thoracic and skeletal radiographs with 12-bit digitized images of the same radiographs in terms of subjective image quality and accuracy of diagnosis of subtle disease. MATERIALS AND METHODS: Thirty-six chest radiographs with normal findings, 48 chest radiographs with abnormal findings, 29 skeletal radiographs with normal findings, and 26 skeletal radiographs with abnormal findings were included in this study. The images were chosen for the subtlety of their findings (nodules, pneumothoraces, interstitial lung disease, fractures). Each set of images was laser-digitized and viewed independently by three radiologists at a teleradiology workstation with a 1280 x 1024 pixel matrix monitor equipped with an eight-bit-per-pixel gray-scale display. All images were viewed at maximum resolution. After review of the digitized images for image quality and for the presence of abnormalities, each radiologist analyzed the analog images in a similar way. RESULTS: Sensitivities for detecting nodules, pneumothoraces, and interstitial lung disease on digitized chest radiographs were 58%, 75%, and 90%, respectively, compared with 62%, 79%, and 92%, respectively, on the original radiographs. Sensitivity for fracture detection on digitized bone radiographs was 87% compared with 88% on analog radiographs. None of these differences was statistically significant. CONCLUSION: Digitization of radiographs for primary diagnosis by teleradiology results in a slight decrease in sensitivity for detection of subtle abnormalities, provided that the images are viewed at maximum resolution.

Identification and spatial distribution of the mRNA encoding the gp49 component of the gilthead sea bream, Sparus aurata, egg envelope.

A cDNA encoding the precursor of one of the major components of gilthead sea bream, Sparus aurata, egg envelope has been cloned by reverse transcriptase polymerase chain reaction (RT-PCR) techniques. The clone was isolated starting from total RNA extracted from the liver of spawning female fish and estradiol-17 beta-treated male fish. Sequence analysis revealed that the cDNA encoded a protein of 405 aa corresponding to 49-kDa component (termed gp49), a glycoprotein belonging to the N-linked type. The gp49 protein is homologous to the Zl-3 of medaka Oryzias latipes, the mammalian ZPC and ZPC homologues of Xenopus laevis (xlZPC) and carp Cyprinus carpio (ccZPC). In addition, the open reading frame also encodes an additional aa sequence, the signal peptide, located in the N-terminal region of the protein. RT-PCR and in situ expression analyses evidenced an organ-restricted pattern: the mRNA was detected only in liver of spawning female and estradiol-17 beta-treated male fish but not in other tissues.

[Diagnosis and treatment of affective disorders]. / Diagnose und Behandlung der affektiven Störungen.

The rates of major depression (5-12%) are considerably higher than for bipolar disorder (ca. 1%). Depressive disorder is most frequent in general practice. Although general practitioners recognise and manage efficiently a large number of depressed patients, at any consultation about half the patients are not diagnosed. Recognising depression is made difficult by the frequency in general practice of presentations with somatic symptoms (masked depression) and of depression related to physical disorder. The best method for the general practitioner to overcome these problems is by using a relatively direct interview for the main specific symptoms of depression. The general practitioner has a key role in the management of depression and as a gatekeeper with a prime responsibility to make appropriate referrals to specialists. Counselling members of the family or friends and recommending self-help groups are important to improve the therapeutic compliance of the patients.