A postmitotic role for Isl-class LIM homeodomain proteins in the assignment of visceral spinal motor neuron identity

LIM homeobox genes have a prominent role in the regulation of neuronal subtype identity and distinguish motor neuron subclasses in the embryonic spinal cord. We have investigated the role of Isl-class LIM homeodomain proteins in motor neuron diversification using mouse genetic methods. All spinal motor neuron subtypes initially express both Isl1 and Isl2, but Isl2 is rapidly downregulated by visceral motor neurons. Mouse embryos lacking Isl2 function exhibit defects in the migration and axonal projections of thoracic level motor neurons that appear to reflect a cell-autonomous switch from visceral to somatic motor neuron character. Additional genetic mutations that reduce or eliminate both Isl1 and Isl2 activity result in more pronounced defects in visceral motor neuron generation and erode somatic motor neuron character. Thus, an early phase of high Isl expression and activity in newly generated motor neurons permits the diversification of visceral and somatic motor neuron subtypes in the developing spinal cord.     

Residential sunlight exposure is associated with a decreased risk of prostate cancer

The possibility that exposure to sunlight reduces the risk of clinical prostate cancer has been strongly suggested by ecologic data. However, data on prostate cancer risk in relation to sunlight exposure in individuals are sparse. We analyzed data from the First National Health and Nutrition Examination Survey (NHANES I) Epidemiologic Follow-up Study in order to test the hypothesis that residential sunlight exposure reduces the risk of prostate cancer. We identified 153 men with incident prostate cancer from a cohort of 3414 white men who completed the baseline interview and dermatologic examination in 1971-1975 and were followed up to 1992. We used Cox proportional hazards modeling to estimate relative risks (RR) and 95% confidence intervals (CI) for measures of residential sunlight exposure, adjusting for age, family history of prostate cancer, and dietary intake of fat and calcium. Residence in the South at baseline (RR = 0.68, CI = 0.41-1.13), state of longest residence in the South (RR = 0.62, CI = 0.40-0.95), and high solar radiation in the state of birth (RR = 0.49, CI = 0.30-0.79) were associated with significant and substantial reductions in prostate cancer risk. These data support the hypothesis that sunlight exposure reduces the risk of prostate cancer and have important implications for prostate cancer prevention.     

Effects of green tea polyphenol on preservation of human saphenous vein

The potential role of green tea polyphenol (GtPP) in preserving the human saphenous vein was investigated under physiological conditions. The vein segments were incubated for 1, 3, 5, 7 and 14 days, either after 4h of treatment with 1.0mg/ml GtPP or in the presence of GtPP at the same concentration. After incubation, the endothelial cell viability, endothelial nitric oxide synthase (eNOS) expression and the vein histology were evaluated. When the veins were not treated with GtPP, the viability of the endothelial cells was significantly reduced with the progress in the culture time, and none of the cells expressed eNOS after 5 days. Furthermore, severe histological changes and structural damage were observed in the non-treated veins. In contrast, incubating the veins after 4h of GtPP treatment significantly prevented these phenomena. The cellular viability of the GtPP-treated vein was approximately 64% after 7 days, and eNOS expression was maintained up to 40%, compared to that of the fresh vein. The histological observations showed that the vasculature was quite similar to that of the fresh vein. When incubated with GtPP, the vein could also be preserved for 1 week under physiological conditions retaining both its cellular viability (61%) and eNOS expression level (45%) and maintaining its venous structure without any morphological changes. These results demonstrate that GtPP treatment may be a useful method for preserving the HSV.     

Optochemical nanosensor PEBBLEs: photonic explorers for bioanalysis with biologically localized embedding

Nanosized photonic explorers for bioanalysis with biologically localized embedding (PEBBLEs) have been created for the intracellular monitoring of small analytes (e.g. H(+), Ca(2+), Mg(2+), Zn(2+), O(2), K(+), Na(+), Cl(-), OH and glucose). The probes are based on the inclusion of fluorescent analyte-sensitive indicator dyes and analyte-insensitive reference dyes in a polymer (polyacrylamide, polydecylmethacrylate) or sol-gel (silica, ormosil) nanoparticle. The probes are ratiometric, reversible and protected from interaction with the cellular environment, a quality which is of benefit to the integrity of both the cell and the sensor functionalities. Herein we describe two types of PEBBLE sensors, direct measurement sensors and ion correlation sensors, as well as the use of these PEBBLEs in intracellular sensing.     

Changes in parvalbumin immunoreactivity in the parietofrontal cortex after transient forebrain ischemia in the Mongolian gerbil

We investigated the changes in parvalbumin (PV)-immunoreactive (IR) neurons in the parietofrontal cortex after transient forebrain ischemia. In the sham-operated group, PV-IR neurons were present in all layers of the parietofrontal cortex except layer I. Shortly after ischemia the number of PV-IR neurons in layer II/III first increased, and then declined dramatically 12 h after ischemic insult, followed by a second increase after 2 days. At this time the PV immunoreactivity was very weak and only present in the peripheral neuronal cytoplasm. The reversible increase in the number of PV-IR neurons and in the level of their immunoreactivity could result from a transient ischemia-induced increase in intracellular calcium. This pattern of expression was particularly pronounced in layer II/III of the parietofrontal cortex, suggesting that these neurons are especially\susceptible to ischemic insult.     

Retrovirus-mediated gene transfer and expression of EGFP in chicken

Here, we successfully demonstrate expression of the EGFP (enhanced green fluorescence protein) gene in chickens using replication-defective MLV (murine leukemia virus)-based retrovirus vectors encapsidated with VSV-G (vesicular stomatitis virus G glycoprotein). The recombinant retrovirus was injected beneath the blastoderm of non-incubated chicken embryos (stage X). After 12 days incubation, all of the eight living embryos assayed were found to express this vector-encoded EGFP gene, which was under the control of the RSV (Rous Sarcoma Virus) promoter, in diverse organ tissues, including head, beak, neck, wing, hock, tail, toes, heart, amnion, and yolk sac. Surprisingly, despite the presumed cytotoxicity of EGFP, some embryos hatched and survived and these had prominent green fluorescent spots, both in internal organs and externally.     

Regulation of MUC5AC mucin secretion and airway surface liquid metabolism by IL-1beta in human bronchial epithelia

Mucociliary transport in the airways significantly depends on the liquid and mucin components of the airway surface liquid (ASL). The regulation of ASL water and mucin content during pathological conditions is not well understood. We hypothesized that airway epithelial mucin production and liquid transport are regulated in response to inflammatory stimuli and tested this hypothesis by investigating the effects of the pleiotropic, early-response cytokine, IL-1beta, on cultured primary human bronchial epithelial and second-passage, normal human tracheo-bronchial epithelial (NHTBE) cell cultures. Fully differentiated NHTBE cultures secreted two major airway mucins, MUC5AC and MUC5B. IL-1beta, in a dose- and time-dependent manner, increased the secretion of MUC5AC, but not MUC5B. MUC5AC mRNA levels were only transiently increased at 1 and 4 h after the start of IL-1beta treatment and returned to control levels thereafter, even though MUC5AC mucin production remained elevated for at least 72 h. Synchronous with elevated MUC5AC secretion, ASL volume increased, its percentage of solid was reduced, and the pH/[HCO(3)(-)] of the ASL was elevated. ASL volume changes reflected altered ion transport, including an upregulation of Cl(-) secretory currents (via CFTR and Ca(2+)-activated Cl(-) conductance) and an inhibition of epithelial sodium channel (ENaC)-mediated absorptive Na(+) currents. IL-1beta increased CFTR mRNA levels without affecting those for ENaC subunits. The synchronous regulation of ASL mucin and liquid metabolism triggered by IL-1beta may be an important defense mechanism of the airway epithelium to enhance mucociliary clearance during airway inflammation.