Obesity is a potential risk factor for cognitive deficits in the elder humans. Using a high-fat diet (HFD)–induced obese mouse model, we investigated the impacts of HFD on obesity, metabolic and ...stress hormones, learning performance, and hippocampal synaptic plasticity. Both male and female C57BL/6J mice fed with HFD (3 weeks to 9–12 months) gained significantly more weights than the sex-specific control groups. Compared with the obese female mice, the obese males had similar energy intake but developed more weight gains. The obese male mice developed hyperglycemia, hyperinsulinemia, hypercholesterolemia, and hyperleptinemia, but not hypertriglyceridemia. The obese females had less hyperinsulinemia and hypercholesterolemia than the obese males, and no hyperglycemia and hypertriglyceridemia. In the contextual fear conditioning and step-down passive avoidance tasks, the obese male, but not female, mice showed poorer learning performance than their normal counterparts. These learning deficits were not due to sensorimotor impairment as verified by the open-field and hot-plate tests. Although, basal synaptic transmission characteristics (input–output transfer and paired-pulse facilitation (PPF) ratio) were not significantly different between normal and HFD groups, the magnitudes of synaptic plasticity (long-term potentiation (LTP) and long-term depression (LTD)) were lower at the Schaffer collateral-CA1 synapses of the hippocampal slices isolated from the obese male, but not female, mice, as compared with their sex-specific controls. Our results suggest that male mice are more vulnerable than the females to the impacts of HFD on weight gains, metabolic alterations and deficits of learning, and hippocampal synaptic plasticity.
Abstract (−)-Epigallocatechin-3-gallate (EGCG), an active ingredient in green tea, was known to effectively inhibit formation and development of tumors. However, excessive uptake of EGCG was also ...known to cause cytotoxicity to normal cells. In this study, EGCGs that were physically attached onto the surface of nanogold particles (pNG) was confirmed by scanning electron microscopy. The anticancer activity of the EGCG-adsorbed pNG was investigated in C3H/HeN mice subcutaneously implanted with MBT-2 murine bladder tumor cells. EGCG–pNG was confirmed to inhibit tumor cell growing by means of cell apoptosis. The mechanism that EGCG–pNG mediates tumor apoptosis was uncovered to activate the caspase cascade through the Bcl-family proteins in the mitochondrial pathway. Additionally, the mechanism that tumors were suppressed by injecting EGCG–pNG directly into the tumor site was determined to be through downregulation of VEGF, whereas that by oral administration of EGCG was through reversing immune suppression upon cancer progression. In this assessment, the prepared EGCG–pNG was confirmed to be more effective than free EGCG in inhibiting bladder tumor in model mice.
(-)-Epigallocatechin-3-gallate (EGCG), the major bioactive constituent in green tea, has been reported to effectively inhibit the formation and development of tumors. To maximize the effectiveness of ...EGCG, we attached it to nanogold particles (EGCG-pNG) in various ratios to examine in vitro cytotoxicity and in vivo anti-cancer activity. EGCG-pNG showed improved anti-cancer efficacy in B16F10 murine melanoma cells; the cytotoxic effect in the melanoma cells treated with EGCG-pNG was 4.91 times higher than those treated with EGCG. The enhancement is achieved through mitochondrial pathway-mediated apoptosis as determined by annexin V assay, JC-10 staining, and caspase-3, -8, -9 activity assay. Moreover, EGCG-pNG was 1.66 times more potent than EGCG for inhibition of tumor growth in a murine melanoma model. In the hemolysis assay, the pNG surface conjugated with EGCG is most likely the key factor that contributes to the decreased release of hemoglobin from human red blood cells.
As a new cooling scheme for electric rotor machines, the impinging jets issued from the armature onto the stator with the spent flows directed toward two annular exits at both ends can convect the ...Joule heat out of the rotor machinery effectively. An experimental study is accordingly devised to investigate the heat transfer performances over the outer cylinder of a concentric annulus with an impinging jet-array issued from the rotating inner cylinder. Intermittencies of impinging jets and spent flows in the Taylor–Couette–Poiseuille annular flow feature the dominant flow physics that affect the heat transfer performances. A set of selected experimental data illustrates the isolated and interdependent influences of jet Reynolds number (
Re), Taylor number (
Ta) and rotating Grashof number (
Gr
ω
) on local and area-averaged Nusselt numbers (
Nu and
Nu
¯
). With the present parametric conditions examined, the coupled
Re,
Ta and
Gr
ω
effects have led the ratios of rotational and non-rotational
Nu
¯
in the range of 0.75–1.48. In conformity with the experimentally revealed heat transfer physics, the heat transfer correlation that permits the evaluation of
Nu
¯
over the outer cylinder of the concentric annulus subject to jet-array impingement from the rotating inner cylinder is generated.
Learning in a contextual fear conditioning task involves forming a context representation and associating it with a shock. The dorsal hippocampus (DH) is implicated in representing the context, but ...whether it also has a role in associating the context and shock is unclear. To address this issue, male Wistar rats were trained on the task by a two-phase training paradigm, in which rats learned the context representation on day 1 and then reactivated it to associate with the shock on day 2; conditioned freezing was tested on day 3. Lidocaine was infused into the DH at various times in each of the two training sessions. Results showed that intra-DH infusion of lidocaine shortly before or after the context training session on day 1 impaired conditioned freezing, attesting to the DH involvement in context representation. Intra-DH infusion of lidocaine shortly before or after the shock training session on day 2 also impaired conditioned freezing. This deficit was reproduced by infusing lidocaine or APV (α-amino-5-phosphonovaleric acid) into the DH after activation of the context memory but before shock administration. The deficit was not due to drug-induced state-dependency, decreased shock sensitivity or reconsolidation failure of the contextual memory. These results suggest that in contextual fear conditioning integrity of the DH is required for memory processing of not only context representation but also context–shock association.
The inhibitor of differentiation-1 protein (Id-1) is over expressed in multidrug resistance prostate cancer cells. We determined the effect of Id-1 expression and its underlying pathways on the ...development of multidrug resistance in prostate cancer.
AT3 cells were transfected with the Id-1 gene or a blank vector. Id-1 mRNA expression was determined by reverse transcriptase-polymerase chain reaction and Id-1 protein content was detected by immunoblot and flow cytometry. Cellular cytotoxicity was determined by MTT (microculture 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay (Sigma Chemical Co., St. Louis, Missouri). The activation and expression of mitogen-activated protein kinase (MAPK) were measured by transactivation assay and Western blotting, respectively.
Id-1 overproduction drove AT3 cells to become resistant to chemotherapeutic agents but did not induce mdr-1 gene expression. The p38MAPK and c-jun N-terminal kinase (JNK) pathways were suppressed, which correlated with increased Id-1 expression. No significant change in extracellular signal-regulated kinase (ERK) activation was observed in Id-1 transfectants compared with that of AT3 or vector control. Treatment of Id-1 expressing cells with p38MAPK and JNK inhibitors resulted in decreased doxorubicin induced apoptosis. In contrast, Id-1 expressing cells treated with ERK inhibitor made cells more sensitive to drug induced apoptosis.
Up-regulation of Id-1 was found in prostate cancer multidrug resistant cells. Sustained ERK activation, and JNK and p38MAPK inhibition by Id-1 in cells may confer drug resistance. These changes in MAPKs could be a mechanism for the acquisition of multidrug resistance in prostate cancer.
Intravesical immunotherapy with live Mycobacterium bovis bacillus Calmette-Guérin (BCG) is the treatment of choice for superficial bladder cancers. Nevertheless, a significant proportion of patients ...do not respond to this therapy, and adverse effects are common. Here, we report the cloning of recombinant mycobacterial DNA vaccines and demonstrate the ability of multicomponent and multisubunit DNA vaccines to enhance Th1-polarized cytokine-mediated responses as well as effector cell responses. Splenocytes from immunized groups of mice were restimulated in vitro and examined for cytotoxicity against murine bladder tumur (MBT-2) cells. We used four combined recombinant BCG DNA vaccines (poly-rBCG) for electroporative gene immunotherapy (EPGIT) in vivo, and found that tumor growth was significantly inhibited and mouse survival was prolonged. Increased immune cell infiltration and induction of apoptosis were noted after treatment with poly-rBCG alone, with the murine interleukin-12 (mIL-12) vaccine alone, and-most significantly-with the poly-rBCG+mIL-12 vaccine combination. Electroporation of poly-rBCG+mIL-12 resulted in complete tumor eradication in seven of eight mice (P<.01) within 28 days. Thus, EPGIT using multicomponent multisubunit BCG is highly effective in the treatment of bladder cancer. This approach presents new possibilities for the treatment of bladder cancer using recombinant BCG DNA vaccines.
Contextual fear conditioning involves forming a context representation and associating it to a shock, both of which involved the dorsal hippocampus (DH) according to our recent findings. This study ...tested further whether the two processes may rely on different neurotransmitter systems in the DH. Male Wistar rats with cannula implanted into the DH were subjected to a two-phase training paradigm of contextual fear conditioning to separate context learning from context-shock association in two consecutive days. Immediately after each training phase, different groups of rats received bilateral intra-DH infusion of the GABA(A) agonist muscimol, 5HT(1A) agonist 8-OH-DPAT, NMDA antagonist APV or muscarinic antagonist scopolamine at various doses. On the third day, freezing behavior was tested in the conditioning context. Results showed that intra-DH infusion of muscimol impaired conditioned freezing only if it was given after context learning. In contrast, scopolamine impaired conditioned freezing only if it was given after context-shock training. Posttraining infusion of 8-OH-DPAT or APV had no effect on conditioned freezing when the drug was given at either phase. These results showed double dissociation for the hippocampal GABAergic and cholinergic systems in memory consolidation of contextual fear conditioning: forming context memory required deactivation of the GABA(A) receptors, while forming context-shock memory involved activation of the muscarinic receptors.
We investigated the efficacy of recombinant bacillus Calmette-Guerin (BCG) DNA (
poly-rBCG) and murine interleukin (IL)-12 (
mIL-12) vaccines in inducing T helper 1 polarized cytokines and ...suppressing bladder tumor growth in mice.
Four mycobacteria candidate genes (
Ag85A,
Ag85B,
Mpt64 and
PstS3) were cloned, fused with
ESAT6 and ligated into eukaryotic expression vectors. Combined
poly-rBCG and
mIL-12 vaccines were transferred into a murine bladder tumor model. The efficiency of gene expression was detected using Western blotting, flow cytometry and semiquantitative reverse transcriptase-polymerase chain reaction. Systemic cytokine responses, tumor growth and cumulative survival rates were monitored.
Transfected bladder cancer cells showed high in vitro and in vivo expression of the recombinant subcomponents. Mice with tumors injected with
poly-rBCG plus
mIL-12 produced serum interferon-γ significantly within 21 days but no significant elevations in tumor necrosis factor-α, IL-2, IL-4 or IL-5 were found. On day 28 after electroporation the growth of MBT-2 implants treated with
poly-rBCG,
mIL-12 or
poly-rBCG plus
mIL-12 was significantly inhibited. The cumulative survival of mice treated with
poly-rBCG plus
mIL-12 was significantly higher than that of the other 3 groups.
Highly immunopotent recombinant vaccines of bacillus Calmette-Guerin DNA were produced that elicited T helper 1 immune responses with a high serum interferon-γ level, inhibited tumor growth and prolonged the survival of tumor bearing mice. Thus, electroporation immunogene therapy using
poly-rBCG plus
mIL-12 may be an attractive regimen for the treatment of bladder cancer.
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