The cytochemical localization of adenyl cyclase activity in rat sublingual gland

Adenyl cyclase activity in mucous acinar cells and serous demilune cells of the rat sublingual gland was localized cytochemically. After incubation with adenylyl-imidodiphosphate (AMP-PNP) as substrate, deposits of reaction product are found along the cell membranes bordering the secretory surfaces of serous demilune cells. These are the membranes which participate directly in secretion by fusing with the granule membranes. The granule membranes of the demilune cells do not reveal reaction product, but the membranes of the granules which are fused with and become part of the cell membrane do show deposits. Thus, it appears that the cell membranes which fuse with granule membranes during secretion are associated with a high level of adenyl cyclase activity. In support of this, the luminal membranes of the mucous acinar cells which do not fuse with granule membranes during secretion are not associated with detectable amounts of adenyl cyclase activity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49675/1/1001440407_ftp.pd

Studies on Hypoxia: XI. Long-Term Effects on the Epiphyseal Plate—A Histomeric and Radioautographic Study

Rats were exposed to hypoxia for one week. The mean thickness of epiphyseal plates from control rats was 430 micrometers (μm) which was reduced to 313 μm in hypoxic rats. Radioautographic incorporation of 3H-phenylalanine by connective tissue cells in hypoxic rats was reduced up to 38% in control rats.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66916/2/10.1177_00220345760550031301.pd

The effect of actinomycin D on the fibroblast of the pulp of the rat incisor : A study by quantitative radioautography and electron microscopy

The effect of actinomycin D on the fibroblast of the dental pulp of continuously growing rat incisors is studied by means of radioautography and electron microscopy. Results of grain counts of radioautographs at various times following an injection of H3-leucine indicate that there is a progressive decrease in incorporation of the isotope by fibroblasts which reaches a maximum decrease on day 7 and subsequently regenerate to a near normal value by the end of the experiment on day 21.Electron microscopic observations of the fine structure of the fibroblast parallel the radioautographic findings in that the maximum degeneration of intracellular structures is observed on day 7 with gradual recovery from that point on. The most seriously affected structures are the rough surfaced endoplasmic reticulum, the Golgi apparatus and the appearance of polyribosomes, the structures that are thought to be directly involved in the elaboration and secretion of proteins. In addition, increased irregularity in size and shape of mitochondria is observed. A large number of lipid droplets as well as cytolysomes appear during the period between 7 and 10 days. The observations on the nucleolus confirm descriptions by previous workers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33347/1/0000744.pd

Piperlongumine inhibits LMP1/MYC-dependent mouse B-lymphoma cells

AbstractPiperlongumine (PL), isolated from the fruit of Long pepper, Piper longum, is a cancer-inhibiting compound that selectively kills tumor cells while sparing their normal counterparts. Here we evaluated the efficacy with which PL suppresses malignant B cells derived from a newly developed, double-transgenic mouse model of human endemic Burkitt lymphoma (BL), designated mCD40-LMP1/iMycEμ. PL inhibited tumor cell proliferation in a concentration-dependent manner and induced apoptosis of neoplastic but not normal B cells. Treatment with PL resulted in downregulation of EBV-encoded LMP1, cellular Myc, constitutive NF-κB activity, and a host of LMP1-Myc-NF-κB-regulated target genes including Aurka, Bcat1, Bub1b, Ccnb1, Chek1, Fancd2, Tfrc and Xrcc6. Of note, p21Cip1-encoding Cdkn1a was suppressed independent of changes in Trp53 mRNA levels and p53 DNA-binding activity. Considering the central role of the LMP1–NF-κB–Myc axis in B-lineage neoplasia, these findings further our understanding of the mechanisms by which PL inhibits B-lymphoma and provide a preclinical rationale for the inclusion of PL in new interventions in blood cancers

Age-related decline in protein synthesis in the rat parotid gland

This study was undertaken to determine whether protein synthesis declines with age in parorid salivary glands. We have examined the level of incorporation of [3H]-leucine into protein and the metabolism of [U-14C]-D-glucose in 2-, 12-, 18-, 24- and 30-month-old rats. The rate of incorporation of [3H]-leucine into perchloric acid insoluble protein by gland slices decreases progressively with age from 138.43+/-5.43 nmole/mg DNA/h at 2 months to 109.77+/-6.88, 97+/-4.68, 71.62+/-4.13 and 58.08+/-5.61 nmole/mg DNA/h at 12, 18, 24 and 30 months, respectively. The amount of radioactivity in the perchloric acid soluble fraction remains relatively stable at all ages. The ability of gland slices to oxidize [U-14C]-D-glucose to 14CO2 and to incorporate radioactivity into the total lipid does not change with age, whereas the incorporation of radioactivity into protein decreases significantly from 45.06+/-3.55 at 2 months to 21.75+/-1.30 nmoles glucuse/mg DNA/h at 24 months. Histologically, no significant change is detected in the proportion of secretory cells to ductal cells in the different age groups. In radioautographs of the glands incubated with [3H]-leucine, the distribution of cells with grains is similar in all age groups. Lipid droplets occur at the periphery of the lobules and a large number of lipofuscin granules are present in secretory acinar cells of 12-month-old and older rats when viewed in the electron microscope. However, the structural integrity in the cellular organelles is maintained in the acinar cells of all age groups. These results indicate that the ability of parotid gland cells to synthesize protein decreases with age. The decrease reflects specific changes in protein synthesis and not an overall decline in cellular metabolism or a decrease in the number of cells which incorporate leucine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23360/1/0000304.pd

Tin doped indium oxide core-TiO <inf>2</inf> shell nanowires on stainless steel mesh for flexible photoelectrochemical cells

Photoanode architecture is built on highly conductive tin doped indium oxide (ITO) nanowires (NWs) on a flexible stainless steel mesh (SSM). ITO nanowires were coated with the atomic layer deposition grown TiO 2 layer and the photoelectrochemical performance of the stainless steel mesh based photoanode were examined as a function of wire-length and shell-thickness. The photoanode consisting of 20 m-long nanowire core and 36 nm thick shell increased the photocurrent of the testing cell by 4 times, compared to a reference cell. This enhanced photochemical activity is attributed to higher light harvesting efficiency of nanowire arrays and suppressed charge recombination of core-shell structure. © 2012 American Institute of Physics