Granule neurons generated during development extend divergent axon collaterals to hippocampal area CA3

cAMP is a ubiquitous second messenger, which acts mainly through specific protein kinases that consist of two regulatory and two catalytic subunits. An unsolved problem in cAMP physiology is how it can regulate so many cellular functions through this simple enzymatic cascade. A tentative explanation is related to the different biochemical properties of the four regulatory subunit isoforms (RI alpha and RI beta, RII alpha and RII beta) and to their differential cell and tissue distribution. For example, detergent insoluble aggregates of RI alpha are present in some cholinergic neurons of the adult rat brain. Rat brains, from the embryonic stage to old age, were examined for the presence of highly concentrated clusters of RI alpha. They are present only in some neurons of restricted brain areas, for a limited time span. During development, labeled neurons appear in different brain areas after neuron migration, at a stage of advanced functional maturation. They have their greatest expression after birth but before sexual maturation, and then they slowly decline, persisting only in a few brain areas throughout life. The first appearance, time course, and eventual disappearance is different in the different brain areas: RI alpha clusters appear in brainstem, hypothalamus, and accessory olfactory bulb at a late embryonic stage; in the main olfactory bulb, hippocampus, and medial thalamic nuclei shortly after birth; and in the cortex as late as in the third and fourth postnatal week. During the rat's lifespan, the distribution of these peculiar RI alpha clusters undergo changes that may contribute to shape neuronal responses differentially to agents modifying cAMP levels.     

Speed limits in the cerebellum: constraints from myelinated and unmyelinated parallel fibers

Cerebellar parallel fibers are among the thinnest known vertebrate axons and represent an extreme anatomical adaptation. Until now a systematic examination of their properties across species has not been carried out. We used transmission electron microscopy and light microscopy to compare parallel fibers in mammals of different brain sizes. From mouse to macaque, the average unmyelinated parallel fiber diameter was 0.2-0.3 microm, consistent with the idea that they are evolutionarily selected for compactness. Average unmyelinated parallel fiber diameter scaled up slightly with brain size, and across species the estimated total conduction time is 5-10 ms. However, these conduction times can vary by milliseconds, and unmyelinated PFs consume large amounts of energy per action potential. These functional disadvantages are overcome in myelinated parallel fibers, which we found in the deep regions nearest the Purkinje cell layer in marmoset, cat and macaque. These axons were 0.4-1.1 microm wide, have expected conduction times of 0.5-1.0 ms, and may convey fast feedforward inhibition via basket cells to Purkinje cells.     

Extracellular ATP inhibits apoptosis and maintains cell viability by inducing autocrine production of interleukin-4 in a myeloid progenitor cell line

Interleukin-3 (IL-3)-dependent myeloid progenitor cell FDC.P2 is induced to undergo apoptotic cell death upon IL-3 depletion. Extracellular adenosine triphosphate (ATP) was found to prevent apoptosis and maintain cell viability of FDC.P2 cells upon IL-3 withdrawal. The antiapoptotic effect of ATP required extracellular Ca2+. Furthermore, FK506, a specific inhibitor of calcium/calmodulin-dependent protein phosphatase calcineurin, inhibited the antiapoptotic effect of ATP. As one of cytokines whose expression is dependent on the activation of calcineurin, interleukin-4 (IL-4) played a critical role in ATP-mediated cell survival of FDC.P2 cells because neutralizing antibody against IL-4 effectively abrogated the antiapoptotic activity of ATP. Moreover, ATP treatment induced a significant amount of secreted IL-4 that was sufficient to maintain cell viability. Taken together, our present results demonstrate that extracellular ATP triggers autocrine production of IL-4 through calcium-dependent activation of calcineurin and secreted IL-4 substitutes IL-3 in protecting FDC.P2 cells from apoptosis even in the absence of IL-3.     

Menopausal symptoms among Thai women in Bangkok

A random probability cluster area sampling of 614 women living in Bangkok was conducted to determine the prevalence of abnormal symptoms related to the menopause. Women interviewed were aged 40 and above currently registered as living in the Bangkok Metropolitan area. Sixty-nine percent of the women interviewed experienced abnormal symptoms. Eighty-two percent of those with abnormal symptoms reported having hot flushes. Palpitation, increased heat intolerance and emotional liability were common symptoms. Minor abnormalities included insomnia, weakness, anxiety and urinary symptoms. Changes related to sexual function were difficult to elicit due to cultural limitations. Economic and cultural factors might play important roles in the way these women perceived symptoms related to the menopause and sought medical assistance.     

Cytotoxicity,Acute Oral Toxicity,and Skin Irritation of 2-ethylhexyl-2,4,5-trimethoxycinnamate and di(2-ethylhexyl)-2,4,5-trimethoxybenzalmalonate

Safety of two new ultraviolet (UV) filters, 2-ethylhexyl-2,4,5-trimethoxycinnamate (E8) and 2-ethylhexyl-2,4,5-trimethoxybenzalmalonate (B8), has been evaluated through the human melanoma cytotoxicity test and seven-day acute oral toxicity studies in rats. At 2.5 mg/mL, both compounds gave similar cell viability to the control. LD₅₀ values for E8 and B8 are more than 5000 and 1000 mg/kg body weight, respectively. No significant difference in body weight and hematological parameters among the 0, 5, 50, 500, and 5000 mg/Kg E8-treated animals could be detected. Pathological examination of rat tissues collected at the end of the study period revealed no significant difference between the control and all E8-administered rats. There was no significant difference in all clinical blood chemistry parameters (aspartate aminotransferase, creatinine, blood urea nitrogen, and cholesterol), except alanine aminotransferase (ALT), between the control and the E8-treated animals. All ALT values were, however, in the normal range of SD rats. E8 showed negative results for the skin irritation study on human volunteers, using patch and photopatch tests. Excitation of respiratory signs of dypsnea in 10, 100, and 1000 mg/Kg B8-treated rats could be observed during 1–24 h. All groups were, however, normal during the second to the seventh day. Hematological parameters of the 0, 10, 100, and 1000 mg/Kg B8-treated animals showed no significant difference. Pathological examination revealed no significant difference between the control and all B8-administered rats. However, significant differences in some clinical blood chemistry parameters and body weights between the control and some B8-treated animals could be detected. All values, however, were in the normal ranges of the SD rats.     

Inhibition of gamma-secretase affects proliferation of leukemia and hepatoma cell lines through Notch signaling

Notch signaling is a well-conserved pathway playing crucial roles in regulating cell fate decision, proliferation, and apoptosis during the development of multiple cell lineages. Aberration in Notch signaling is associated with tumorigenesis of tissues from various origins. To investigate the role Notch signaling plays in the proliferation of cancer cell lines, the expression profiles of Notch1 in six human cancer cell lines (Jurkat, HepG2, SW620, KATOIII, A375, BT474) were examined. All cell lines differentially expressed Notch1, and only Jurkat and SW620 expressed cleaved Notch1 (Val1744). Among the six cell lines tested, only Jurkat and HepG2 showed a decrease in cell proliferation during 4 days of treatment with a gamma-secretase inhibitor (GSI). This is the first report on the anti-proliferative effects of GSI on a human hepatoma cell line. These two cell lines expressed Notch1-3, Jagged1, Jagged2, Dlk1 and Hes1. GSI treatment led to a decrease in Hes1 expression in both cell lines. Surprisingly, GSI treatment resulted in the accumulation of Notch1 protein upon treatment. During this period, GSI treatment did not induce apoptosis, but caused cell cycle arrest in both cell lines. This was also correlated with decreased c-myc expression. Forced expression of activated intracellular Notch1 completely abrogated GSI sensitivity in both cell lines. These results clearly demonstrate that Notch signaling positively regulates cell proliferation in Jurkat and HepG2 cell lines and that GSI treatment inhibits tumor cell proliferation through the suppression of Notch signaling.     

Cytotoxicity, acute oral toxicity, and skin irritation of 2-ethylhexyl-2,4,5-trimethoxycinnamate and di(2-ethylhexyl)-2,4,5-trimethoxybenzalmalonate

Safety of two new ultraviolet (UV) filters, 2-ethylhexyl-2,4,5-trimethoxycinnamate (E8) and 2-ethylhexyl-2,4,5-trimethoxybenzalmalonate (B8), has been evaluated through the human melanoma cytotoxicity test and seven-day acute oral toxicity studies in rats. At 2.5 mg/mL, both compounds gave similar cell viability to the control. LD50 values for E8 and B8 are more than 5000 and 1000 mg/kg body weight, respectively. No significant difference in body weight and hematological parameters among the 0, 5, 50, 500, and 5000 mg/Kg E8-treated animals could be detected. Pathological examination of rat tissues collected at the end of the study period revealed no significant difference between the control and all E8-administered rats. There was no significant difference in all clinical blood chemistry parameters (aspartate aminotransferase, creatinine, blood urea nitrogen, and cholesterol), except alanine aminotransferase (ALT), between the control and the E8-treated animals. All ALT values were, however, in the normal range of SD rats. E8 showed negative results for the skin irritation study on human volunteers, using patch and photopatch tests. Excitation of respiratory signs of dypsnea in 10, 100, and 1000 mg/Kg B8-treated rats could be observed during 1-24 h. All groups were, however, normal during the second to the seventh day. Hematological parameters of the 0, 10, 100, and 1000 mg/Kg B8-treated animals showed no significant difference. Pathological examination revealed no significant difference between the control and all B8-administered rats. However, significant differences in some clinical blood chemistry parameters and body weights between the control and some B8-treated animals could be detected. All values, however, were in the normal ranges of the SD rats.     

Delta-like ligand 4 in hepatocellular carcinoma intrinsically promotes tumour growth and suppresses hepatitis B virus replication

AIM To investigate the role of Delta-like ligand 4(DLL4) on tumour growth in hepatitis B virus(HBV)-associated hepatocellular carcinoma(HCC) in vivo.METHODS We suppressed DLL4 expression in an HBV expressing HCC cell line, HepG2.2.15 and analysed the growth ability of cells as subcutaneous tumours in nude mice. The expression of tumour angiogenesis regulators, VEGF-A and VEGF-R2 in tumour xenografts were examined by western blotting. The tumour proliferation and neovasculature were examined by immunohistochemistry. The viral replication and viral protein expression were measured by quantitative PCR and western blotting, respectively.RESULTS Eighteen days after implantation, tumour volume in mice implanted with sh DLL4 HepG2.2.15 was significantly smaller than in mice implanted with control HepG2.2.15(P 0.0001). The levels of angiogenesis regulators, VEGF-A and VEGF-R2 were significantly decreased in implanted tumours with suppressed DLL4 compared with the control group(P 0.001 and P 0.05, respectively). Furthermore, the suppression of DLL4 expression in tumour cells reduced cell proliferation and the formation of new blood vessels in tumours. Unexpectedly, increased viral replication was observed after suppression of DLL4 in the tumours.CONCLUSION This study demonstrates that DLL4 is important in regulating the tumour growth of HBV-associated HCC as well as the neovascularization and suppression of HBV replication.     

Enucleated eye model for intraocular retinal prosthesis implantation.

An enucleated porcine eye model was developed to assess intraocular retinal prosthesis implantation surgery. The surgical technique consists of corneal and crystalline lens removal, keratoprosthesis replacement, and vitrectomy. To test the eye model, the scleral incision was increased to 5 mm and a 10-mm wide retinal prosthesis folded and inserted. One retinal tack was used to fix the prosthesis to the retina. A retinal prosthesis array was inserted without significant damage to the array and conformed to the curvature of the eye. Fundus photography and optical coherence tomography were performed at the end of surgery.