Hybrid cardiac imaging with MR-CAT scan: a feasibility study

We demonstrate the feasibility of a new versatile hybrid imaging concept, the combined acquisition technique (CAT), for cardiac imaging. The cardiac CAT approach, which combines new methodology with existing technology, essentially integrates fast low-angle shot (FLASH) and echoplanar imaging (EPI) modules in a sequential fashion, whereby each acquisition module is employed with independently optimized imaging parameters. One important CAT sequence optimization feature is the ability to use different bandwidths for different acquisition modules. Twelve healthy subjects were imaged using three cardiac CAT acquisition strategies: a) CAT was used to reduce breath-hold duration times while maintaining constant spatial resolution; b) CAT was used to increase spatial resolution in a given breath-hold time; and c) single-heart beat CAT imaging was performed. The results obtained demonstrate the feasibility of cardiac imaging using the CAT approach and the potential of this technique to accelerate the imaging process with almost conserved image quality.     

Role for myelin-associated glycoprotein as a functional tenascin-R receptor

The expression of the immunoglobulin superfamily member myelin-associated glycoprotein (MAG) and the extracellular matrix glycoprotein tenascin-R (TN-R) by oligodendrocytes overlaps in time and space. The two molecules can be neurite outgrowth-inhibitory or -promoting depending on the neuronal cell type and the environment in which they are presented. Here we show that the two molecules directly bind to each other in vitro and that binding sites on TN-R localize to two domains, the fibrinogen domain and the epidermal growth factor-like repeat domain with the N-terminal cysteine-rich stretch. We further show by a functional assay, namely the repulsion of MAG-transfected Chinese hamster ovary cells (CHO) cells from a TN-R substrate, that MAG is part of the signalling pathway of TN-R for cell repulsion. When coated as a uniform substrate, MAG was inhibitory for neurite outgrowth of hippocampal and cerebellar neurons in vitro, when compared to poly-L-lysine, while TN-R enhanced neurite outgrowth. When added to MAG, TN-R neutralized the neurite outgrowth-inhibitory effects of MAG, presumably by blocking the neurite outgrowth-inhibitory domain of MAG.     

Tempo of spectrum change as a cue in speech-sound discrimination by infants

Six- to seven-month-old infants were tested on their ability to discriminate among three speech sounds which differed on the basis of formant-transition duration, a major cue to distinctions among stop, semivowel and diphthong classes. The three speech sounds, [see text] were produced in two different ways. The stimuli for one experiment were two-formant synthetic tokens which differed in formant-transition duration. The stimuli for a second experiment was produced with a computer-modification technique which artificially shortened or lengthened the formant-transition portion of a naturally produced [see text], resulting in tokens of [see text]. The discrimination procedure involved visual reinforcement of a head-turn response following a change from a repeating background stimulus to a contrasting stimulus. Infants in both experiments discriminated [see text]; evidence for [see text] discrimination was obtained for the "computer modified" tokens only. These findings are discussed in terms of possible mechanisms underlying speech perception in infancy.     

609 C --> T polymorphism in NAD(P)H:quinone oxidoreductase gene in patients with prostatic adenocarcinoma or benign prostatic hyperplasia

Allelic variations at the NQO1 locus encoding for NAD(P)H:quinone oxidoreductase have recently been implicated in carcinogenesis, cancer chemoprevention and chemotherapy. Two naturally occurring alleles differ at nucleotide position 609 with the variant allele leading to diminished or absent enzyme activity. Using polymerase chain reaction-restriction fragment length polymorphic analysis, NQO1 genotyping was performed in DNA from blood cells from 54 patients with prostatic adenocarcinoma, 49 patients with benign prostatic hyperplasia and 100 healthy control subjects. Prostatic adenocarcinoma patients and healthy controls demonstrated almost identical genotype distribution and frequencies of the variant allele (17.6 versus 17.5%). The variant allele was slightly more frequent in benign prostatic hyperplasia patients (23.5%). Established prostate cancer-derived cell lines LnCAP, DU-145, and PC-3 demonstrated NQO1 wild-type genotype. Our study does not support the hypothesis that the variant NQO1 allele is a risk modifier for prostatic adenocarcinoma and/or benign prostatic hyperplasia in the Caucasian population.     

Immunohistochemical localization of CD1a-positive putative dendritic cells in human breast tumours

The presence of a high number of infiltrating CD1a+ cells in malignant neoplasms has been reported to be associated with an improved prognosis, reduced tumour recurrence and fewer metastases. This study identified a population of CD1a+ cells within the lymphoid cell infiltrate in human ductal breast carcinoma (n = 52), which was significantly different from normal breast tissue, in which only two out of nine cases expressed CD1a+ cells (P = 0.0192). In the majority of cases, the infiltrate was low compared with the number of macrophages and T cells present (results not shown). There was no correlation between the number of CD1a+ cells and tumour grade, with all tumour grades expressing similar numbers of infiltrating CD1a+ cells. There was clear evidence, however, that the CD1a+ cells were closely associated with tumour cells. It is likely that CD1a+ cells have a role in antigen capture and presentation in human tumours, and this study documents the density of CD1a+ cells in a large sample of all histological grades of human breast carcinomas.     

Cyanopindolol is a highly potent and selective antagonist at the presynaptic serotonin autoreceptor in the rat brain cortex

Summary Rat brain cortex slices preincubated with ³H-serotonin were superfused with physiological salt solution containing the serotonin uptake blocker DU 24565 (6-nitroquipazine). The effects of (±)-cyanopindolol and its enantiomers, of ICI 118,551 (erythro-dl-1-(7-methylindan-4-yloxy)-3-isopropylaminobutan-2-ol) and of isoprenaline on the electrically (3 Hz) evoked ³H overflow were studied.(±)-Cyanopindolol increased the evoked ³H overflow; this effect was prevented by preexposure to the previously characterized serotonin receptor antagonist metitepin. The concentration-response curve of unlabelled serotonin for its inhibitory effect on the electrically evoked ³H overflow was shifted to the right by (±)-cyanopindolol (apparent pA₂ value: 8.29), whereas that of noradrenaline (determined in the absence of DU 24565) was not affected (apparent pA₂ value: <6.0). The concentration-response curve of serotonin was also shifted to the right by (–)-cyanopindolol (apparent pA₂ value: 8.30) and (+)-cyanopindolol (6.83) but not by ICI 118,551 (<5.5). Isoprenaline (up to 10 mol/l; examined in the absence of DU 24565) did not influence the electrically evoked ³H overflow.The present results show that the presynaptic serotonin autoreceptor is blocked by cyanopindolol in a stereoselective way. This drug is 20 times more potent than metitepin as an antagonist at the presynaptic serotonin autoreceptor, and, in contrast to the latter, it does not act as an antagonist at the presynaptic ₂-adrenoceptor on the serotoninergic neurone.This study was supported by a grant of the Deutsche Forschungsgemeinschaft