The basilar pontine nuclei and the nucleus reticularis tegmenti pontis subserve distinct cerebrocerebellar pathways.

Previous studies often considered the basilar pontine nuclei (BPN) and the nucleus reticularis tegmenti pontis (NRTP) as relays of a single cerebro-(ponto)-cerebellar pathway. Conversely, the different cortical afferences to the BPN and the NRTP, as well as the anatomical and functional features of the cerebellopetal projections from these pontine nuclei, support the different, and for some aspect, complementary arrangement of the cerebrocerebellar pathways relayed by the BPN or NRTP. Both the BPN and the NRTP are innervated from the cerebral cortex, but with regional prevalence. The NRTP is principally innervated from motor or sensori-motor areas while the BPN are principally innervated from sensory, mainly teloceptive, and associative area. Projections from sensory-motor areas were also traced to the BPN. The BPN and NRTP project to all parts of the cerebellar cortex with a similar pattern. In fact, from single areas of them projections were traced to set of sagittal stripes of the cerebellar cortex. In variance to such analogies, the projections to the cerebellar nuclei differed between those traced from the NRTP and from BPN. In fact, BPN and NRTP have private terminal areas in the cerebellar nuclei with relatively little overlaps. The BPN innervated the lateroventral part of the nucleus lateralis and the caudoventral aspect of the nucleus interpositalis posterioris. The NRTP principally innervated the mediodorsal part of the nucleus lateralis, the nucleus interpositalis anterioris, the nucleus medialis. Since the single cerebellar nuclei have their specific targets in the extracerebellar brain areas, it follows that the BPN and the NRTP, passing through their cerebellar nuclei relays, are devoted to control different brain areas and thus likely to play different functional roles. From single pontine regions (of both BPN and NRTP) projections were traced to the cerebellar cortex and to the cerebellar nuclei. In some cases these projections reached areas which are likely anatomically connected (by Purkinje axons). This pattern of the pontine projections was termed as coupled projection. In some other cases, the projections reached areas of the cerebellar cortex but not the nuclear regions innervated by them. We termed this as uncoupled projection. The existence of both coupled and uncoupled projections, open new vistas on the functional architecture of the pontocerebellar pathway. More in detail, this study showed the different quantitative and topographic distribution of the coupled and uncoupled projections visualized in the cerebellar projections from BPN and NRTP. All these evidences strongly support the anatomical and the functional differences that characterise the cerebrocerebellar pathways relayed by the BPN and the NRTP.

Cardiac precursors in human bone marrow and cord blood: in vitro cell cardiogenesis.

BACKGROUND: Cell transplantation has come of age but numerous questions still remain. Which type of cell should be used? Cardiac precursors are present in mouse bone marrow and used to repair the infarcted myocardium in mice. We searched for these precursors in human bone marrow and analyzed gene expression patterns in cells induced to differentiate in vitro. METHODS: Cells from human bone marrow were isolated and cultured in medium supplemented with autologous serum and 5% CO2. Cell characterization was performed by immunocytochemical analysis. mRNA was isolated and retrotranscribed. The active genes were detected with polymerase chain reaction by using specific oligonucleotides. RESULTS: Some inducers pushed the cell through different stages of cardiogenesis, with expression of cardiac transcriptional activators and structural proteins. Some combinations of stimuli were able to drive cells to advanced stages of cardiogenesis. CONCLUSIONS: These studies lead to an exact description of in vitro cardiogenesis in humans. Our aim was also to assess the residual proliferative capacity of cells and to enhance the differentiation efficiency, thus maximizing their repair capacity and the likelihood that they functionally integrate with the surrounding cardiac tissue.

Cloning and expression pattern of connexin39, a new member of the gap junction gene family isolated from the neural tube of chicken embryos.

In this study, a new gap junction (GJ) connexin (Cx) gene was isolated from the neural tube of chicken (c) embryos (HH21) and cloned by degenerate reverse transcription-polymerase chain reaction (RT-PCR). The open reading frame of the gene encodes for a protein of 343 amino acid residues with strong similarity to highly conserved connexin sequences. On the basis of the predicted molecular mass of 39144 kDa, we denominated it as cCx39. Sequence analysis allocated the cCx39 to the alpha-group of connexin gene family. The mRNA expression of cCx39 was detected by RT-PCR and Northern blot in several tissues of chicken, including different parts of central nervous system, heart, liver, kidney, aorta and ovary. In situ hybridisation analysis of chicken brain showed strong expression in neurons of granular layers of cerebellum, optic tectum and ectostriatum. The in situ hybridisation of extracererebral tissues revealed strong expression of cCx39 in the atrium of the heart, the external layer of the aorta and endothelium of biliary vessels; moderate expression was found in the endothelium of the aorta.