Connexin32 inhibits gastric carcinogenesis through cell cycle arrest and altered expression of p21Cip1 and p27Kip1

Gap junctions and their structural proteins, connexins (Cxs), have been implicated in carcinogenesis. To explore the involvement of Cx32 in gastric carcinogenesis, immunochemical analysis of Cx32 and proliferation marker Ki67 using tissue-microarrayed human gastric cancer and normal tissues was performed. In addition, after Cx32 overexpression in the human gastric cancer cell line AGS, cell proliferation, cell cycle analyses, and p21^Cip1 and p27^Kip1 expression levels were examined by bromodeoxyuridine assay, flow cytometry, real-time RT-PCR, and western blotting. Immunohistochemical study noted a strong inverse correlation between Cx32 and Ki67 expression pattern as well as their location. In vitro, overexpression of Cx32 in AGS cells inhibited cell proliferation significantly. G₁ arrest, up-regulation of cell cycle-regulatory proteins p21^Cip1 and p27^Kip1 was also found at both mRNA and protein levels. Taken together, Cx32 plays some roles in gastric cancer development by inhibiting gastric cancer cell proliferation through cell cycle arrest and cell cycle regulatory proteins. [BMB Reports 2013; 46(1): 25-30]     

Settlement and habitat use by juvenile pike in early winter

The spatial distribution and social behaviour of young-of-the-year pike Esox lucius was investigated in early winter. Reed beds were selected in the early exploration phase but thereafter, pike congregated in the pool habitat. A significant increase in pool occupancy combined with a decrease in reed bed occupancy and movement indicated settlement within 3 days. There was no evidence of territoriality, which has been reported previously in adult pike: indeed, inter-individual spacing was consistent with social grouping rather than territory defence. The strong preference for reed cover among juveniles reported in other studies that were undertaken during summer was not observed here. Among-individual variation in exploratory behaviour was observed but this was not related to activity levels or habitat use.     

The influence of Ca2+ on the lateral lipid distribution and phase transition in phosphatidylethanolamine/phosphatidylserine vesicles

The lateral lipid distribution within dipalmitoylphosphatidylethanolamine (DPPE)/dipalmitoylphosphatidylserine (DPPS) vesicle membranes was investigated under the influence of Ca²⁺ using a lipid cross-linking method. To characterize the phase transition in DPPE/DPPS vesicles and to correlate the different phase states of the membrane lipids with the obtained lipid distribution ESR measurements using a fatty acid spin label were carried out. It is shown that Ca²⁺ has a significant influence on the lateral lipid distribution within the fluid phase of the membrane lipids; instead of a slight alternating lipid arrangement in absence of Ca²⁺ due to the electrostatic interaction between the DPPS headgroups after addition of Ca²⁺ a lateral cluster structure is characteristic of the fluid phase.     

Some Tests for k£2 Upper Outliers in an Exponential Sample

The sequential procedure for testing up to k upper outliers proposed by Kimber (1982) for one-parameter exponential distribution is modified to a two-parameter exponential distribution. Further null distributions of some test statistics for an upper outlier-pair in a complete or censored sample from a two-parameter exponential distribution are given. Percentage points of the statistic T₁ are tabulated.     

Regional and Cortical Laminar Distributions of Serotonin S2, Benzodiazepine, Muscarinic, and Dopamine D2 Receptors in Human Brain

Serotonin S2, benzodiazepine, and muscarinic receptors showed different regional distributions in the human brain but were present in all cortical areas. The laminar distributions of [3H]ketanserin, [3H]diazepam, and [3H]quinuclidinylbenzilate were investigated in the temporal cortex and revealed a high density in the IIIrd and IVth layers. Dopamine D2 receptors were not detected in the cortex.     

The life-history strategy of deepwater sculpin, Myoxocephalus thompsoni (Girard), in Lake Michigan: dispersal and settlement patterns during the first year of life

Deepwater sculpin, Myoxocephalus thompsoni (Girard), were sampled from six stations from the 15–100 m depth contours in Lake Michigan between April 1983 and July 1984. In south-eastern Lake Michigan M. thompsoni lay benthic eggs in offshore waters, which hatch between November and August, with peak hatching in March. Abundance of larvae in pelagic samples was higher offshore than inshore, but larval size was greater and development more advanced at inshore stations, indicating an inshore movement after hatching. Larvae reached metamorphosis at 20 mm and settled to the bottom beginning in July. Pelagic larvae 20–40 mm were found in the lower water column at all stations, but newly settled individuals were only captured with bottom trawls at inshore locations (≤60 m depth). Data from ichthyoplankton and bottom trawl samples in 1983 and 1984 indicated that locations for successful settlement of larvae to the bottom extended only as deep as the shallowest fringe of the adult population (> 50 m in 1983). In 1983, maximum density of larvae reached 0.4 individuals m⁻³ by June. Survival from the pelagic larval stage to the demersal young-of-year stage in 1983/1984 was c . 0.1–0.4%. The specific mechanism of mortality at the time of transition to a demersal habit has not been determined.     

Subcellular Distribution of Two Spin Trapping Agents in Rat Heart: Possible Explanation for Their Different Protective Effects Against Doxorubicin-Induced Cardiotoxicity

Previous investigations, performed on isolated rat atria, showed that the lipophylic spin-trapping agent N-tert-butyl-alpha-phenylnitrone (PBN) is able to prevent the acute cardiotoxic effects produced by doxorubicin (DXR), whereas the hydrophylic compound 5,5-dimethyl-pyrroline-N-oxide (DMPO) is inactive. The present study was designed to ascertain whether differences in the pharmacological effects of the two spin traps are related to their different subcellular distribution. Langendorff rat hearts were perfused for 60 minutes with [^I4C]-DXR and either PBN or DMPO. The subcellular mapping of the three compounds was performed by measuring DXR by liquid scintillation counting, PBN by GC/MS, and DMPO by HPLC in the following isolated fractions: nuclei, mitochondria, sarcoplasmic reticulum, sarcolemma, cytosol. DMPO was shown to accumulate in the cytosolic compartment; both PBM and DXR are taken up by nuclei and mitochondria, while only trace amounts of DXR were detected in the sarcoplasmic reticulum. These results suggest that mitochondrial (and not sarcoplasmic) enzymes are mainly involved in DXR-induced free radical production, which is thought to cause the acute cardiotoxic effects of DXR. An involvement of DXR-induced free radical generation in the nuclear compartment seems unlikely in the short-term “in vitro” effects observed with the experimental model adopted for these studies, although it may play a role in the delayed pathology.