Detection of endogenous retinoids in the molluscan CNS and characterization of the trophic and tropic actions of 9-cis retinoic acid on isolated neurons.

Retinoic acid (RA) is an active metabolite of Vitamin A that plays an important role in the growth and differentiation of many cell types. All-trans RA (atRA) is the retinoic acid isomer that has been most widely studied in the nervous system, and can induce and direct neurite outgrowth from both vertebrate and invertebrate preparations. The presence and role of the 9-cis-RA isomer in the nervous system is far less well defined. Here, we used high-pressure liquid chromatography (HPLC) and mass spectrometry (MS) to show for the first time, the presence of both atRA and 9-cis-RA in the CNS of an invertebrate. We then demonstrated that 9-cis-RA was capable of exerting the same neurotrophic and chemotropic effects on cultured neurons as atRA. In this study, significantly more cells showed neurite outgrowth in 9-cis-RA versus the EtOH vehicle control, and 9-cis-RA significantly increased the number and length of neurites from identified neurons after 4 d in culture. 9-cis-RA also extended the duration of time that cells remained electrically excitable in culture. Furthermore, we showed for the first time in any species, that exogenous application of 9-cis-RA induced positive growth cone turning of cultured neurons. This study provides the first evidence for the presence of both atRA and 9-cis-RA in an invertebrate CNS and also provides the first direct evidence for a potential physiological role for 9-cis-RA in neuronal regeneration and axon pathfinding.

Human myocardium: single-breath-hold MR T1 mapping with high spatial resolution--reproducibility study.

A prospective study approved by the local ethics committee was performed to establish the normal range and reproducibility of myocardial T1 values as assessed with single-breath-hold T1 mapping with high spatial resolution. With a 1.5-T magnetic resonance (MR) imaging system, baseline and contrast material-enhanced modified Look-Locker inversion recovery, or MOLLI, imaging was performed in 15 healthy volunteers who had given written informed consent. Image quality scores and myocardial T1 values were derived for standard short-axis segments and sections. Results were compared with those from a second MR imaging study performed on the same day (baseline only) and those from a third study performed on a different day (baseline and contrast enhanced; eight volunteers). Intra- and interobserver agreement were determined. Myocardial T1 maps were obtained rapidly in a reproducible fashion. A normal range for baseline and postcontrast myocardial T1 was established (baseline mean T1 in short-axis sections, 980 msec +/- 53 [standard deviation]; 95% confidence interval: 964, 997; number of sections, 43). This technique could enable direct quantification of changes in tissue characteristics in ischemic and inflammatory myocardial diseases.

Pleomorphic rhabdomyosarcoma in an adult forearm: a case report.

Pleomorphic rhabdomyosarcoma (RMS) is a rare malignancy, and treatment protocols for this tumor are not established. Although Intergroup Rhabdomyosarcoma Study data have led to improvement in overall and disease-free survival for children with juvenile RMS, the applicability of those findings to adult pleomorphic RMS is uncertain. This report presents the case of a 29-year-old man with pleomorphic RMS of the forearm (a location not previously reported in current literature); reviews the immunohistochemical, ultrastructural, and histologic diagnostic criteria; and discusses treatment.