Neural Networks for Mindfulness and Emotion Suppression

Mindfulness, an attentive non-judgmental focus on “here and now” experiences, has been incorporated into various cognitive behavioral therapy approaches and beneficial effects have been demonstrated. Recently, mindfulness has also been identified as a potentially effective emotion regulation strategy. On the other hand, emotion suppression, which refers to trying to avoid or escape from experiencing and being aware of one’s own emotions, has been identified as a potentially maladaptive strategy. Previous studies suggest that both strategies can decrease affective responses to emotional stimuli. They would, however, be expected to provide regulation through different top-down modulation systems. The present study was aimed at elucidating the different neural systems underlying emotion regulation via mindfulness and emotion suppression approaches. Twenty-one healthy participants used the two types of strategy in response to emotional visual stimuli while functional magnetic resonance imaging was conducted. Both strategies attenuated amygdala responses to emotional triggers, but the pathways to regulation differed across the two. A mindful approach appears to regulate amygdala functioning via functional connectivity from the medial prefrontal cortex, while suppression uses connectivity with other regions, including the dorsolateral prefrontal cortex. Thus, the two types of emotion regulation recruit different top-down modulation processes localized at prefrontal areas. These different pathways are discussed.     

Adult rat hepatocytes cultured on an oxygen-permeable film increases the activity of albumin secretion

Primary culture of rat hepatocyte was performed in an oxygen-permeable film dish (F-dish), which would be expected to give an oxygen-rich culture condition. In the conventional culture dish in which the depth of medium was 2 mm, the oxygen tension (pO₂) in the medium decreased from 19% (144 mmHg) to 0.3% (2.3 mmHg) within 2 hr, while the pO₂ in the F-dish maintained 8.5% (64.6 mmHg) even after 2 hr. The adverse effect of the oxygen-deficiency appeared in the albumin secretion activity of the hepatocytes and it was more remarkable in the early period of culture. The average rate of albumin secretion for the initial 48 hr was 2.0 μg ml^-1 hr^-1 or 96 μg 10⁶ cells^-1 day^-1 in the F-dish. The average rate of albumin secretion for the initial 12 hr was only 0.36 μg ml^-1 hr^-1 in the conventional culture dish. The activity of ammonia elimination in the F-dish was 20–50% higher than the conventional culture dish. Three-dimensional aggregate was formed only in the F-dish. The advantage of three-dimensional aggregate for albumin secretion was not clear compared with two-dimensional monolayer. This revised version was published online in July 2006 with corrections to the Cover Date.     

Hair analysis for drugs of abuse XIX. Determination of ephedrine and its homologs in rat hair and human hair

A sensitive GC-MS method was developed for the quantitative analysis of ephedrine (EP), phenylpropanolamine (PPA) and methylephedrine (ME) in animal and human hair. After washing with 0.1% sodium dodecyl sulfate, hair samples (10 mg) were added with deuterated internal standards, extracted by 1-h sonication and over night soaking in 2 ml of 5 M HCl-methanol (1:20) at room temperature. Following evaporation of the liquid phase, the residue was dissolved in phosphate buffer solution (pH 6.0) and purified using a solid-phase extraction procedure with Bond Elut Certify columns. Two types of derivatization were compared - using trifluoroacetic anhydride (TFAA) and pentafluoropropionic anhydride (PFPA) - for discrimination of EP and methamphetamine (MA). Derivatized extracts were analyzed by GC-MS in the EI mode using a capillary column (OV-1 equivalent). From the results comparing three GC-MS conditions, PFP-derivatives separated with a temperature gradient of 20°C/min from 60°C to 280°C gave the best resolution between EP and MA. ME was analyzed as a trimethylsilyl derivative using N,O-bis-trimethylsilyl acetamide at the above GC condition. The assay was linear from 0.5 to 50 ng/mg (r=0.998) and capable of detecting less than 50 pg of derivatized EP, PPA and ME on-column. Intra-assay precision was characterized by C.V. values from 5 to 16% in the concentration range of 1–10 ng/mg hair. The method was used for the quantitative determination of EP, PPA and ME in the hair obtained from three rats with dark brown hair after ten intraperitoneal injections (5 mg/kg/day) of the three drugs and from three male and one female volunteers with black hair after an oral dose of 50 mg/day of EP-HCl for three days. Hair samples were collected by shaving from the back of rats and cutting from the scalp of humans 28 days after the first dose. The incorporation rates of EP, PPA and ME into hair (the ratios of [hair concentration] to [AUC]) obtained from the animal experiment were 0.10, 0.07 and 0.03, respectively, which are a little lower than those (0.14, 0.10 and 0.04) of their desoxy-compounds, MA, amphetamine and dimethylamphetamine. EP was detected at an average of 2.25 ng/mg (n=4) in human scalp hair and at a range of 1–29 ng/mg (n=3) in human beard hair until day 14, but its metabolite (PPA) was at a trace level in the hair of the four subjects. The method was successfully used for detection of ME and EP in the hair of a neonate and its mother who was abusing Bron syrup containing ME during the pregnancy.     

Mediator subunits MED1 and MED24 cooperatively contribute to pubertal mammary gland development and growth of breast carcinoma cells

The Mediator subunit MED1 is essential for mammary gland development and lactation, whose contribution through direct interaction with estrogen receptors (ERs) is restricted to involvement in pubertal mammary gland development and luminal cell differentiation. Here, we provide evidence that the MED24-containing submodule of Mediator functionally communicates specifically with MED1 in pubertal mammary gland development. Mammary glands from MED1/MED24 double heterozygous knockout mice showed profound retardation in ductal branching during puberty, while single haploinsufficient glands developed normally. DNA synthesis of both luminal and basal cells were impaired in double mutant mice, and the expression of ER-targeted genes encoding E2F1 and cyclin D1, which promote progression through the G(1)/S phase of the cell cycle, was attenuated. Luciferase reporter assays employing double mutant mouse embryonic fibroblasts showed selective impairment in ER functions. Various breast carcinoma cell lines expressed abundant amounts of MED1, MED24, and MED30, and attenuated expression of MED1 and MED24 in breast carcinoma cells led to attenuated DNA synthesis and growth. These results indicate functional communications between the MED1 subunit and the MED24-containing submodule that mediate estrogen receptor functions and growth of both normal mammary epithelial cells and breast carcinoma cells.     

PTEN is involved in the signal transduction pathway of contact inhibition in endometrial cells

PTEN is involved in the regulation of normal cellular functions in addition to its well–known role as a tumor suppressor. In the present study, we have shown that stable transfection of the PTEN gene into PTEN–mutated endometrial carcinoma cells leads to contact inhibition accompanied by a decreased level of phosphorylated–Akt (p–Akt) expression, an increase in p27^Kip1, and a decrease in β–catenin. PTEN–induced cells with contact inhibition exhibit G0–G1 cell-cycle arrest, and the Ki–67 labeling index is reduced. These changes are canceled by transfection of a double–stranded short–interfering RNA against the PTEN gene. Normal endometrial stromal cells increase their PTEN expression when reaching confluence; this is followed by changes in the expression of Akt–related proteins in the same way as in tumor cells. These results indicate that PTEN, p–Akt, p27, and β–catenin are involved in the signal transduction of contact inhibition and suggest that PTEN may, in part, control the proliferation of endometrial carcinoma cells through the induction of contact inhibition.     

Evidence for activation of Amh gene expression by steroidogenic factor 1

The anti-Müllerian hormone gene (Amh) is responsible for regression in males of the Müllerian ducts. The molecular mechanism of regulation of chicken Amh expression is poorly understood. To investigate the regulation of chicken Amh expression, we have cloned Amh cDNAs from quail and duck as well as the promoter regions of the gene from chicken, quail, and duck. The expression patterns of Amh during embryonic development in these three species were found to be similar, suggesting that the regulatory mechanisms of Amh expression are conserved. The sequence of the proximal promoter of Amh contains a putative binding site for steroidogenic factor 1 (SF1), the protein product of which can up-regulate Amh in mammals. We showed here that SF1 is able to activate the chicken Amh promoter and binds to its putative SF1 binding site. These results suggest that SF1 plays a role in regulation of Amh expression in avian species.     

Solid-liquid phase behavior of binary fatty acid mixtures. 2. Mixtures of oleic acid with lauric acid, myristic acid, and palmitic acid

Solid-liquid phase behavior was investigated for binary fatty acid mixtures composed of oleic acid (OA; cis-9-octadecenoic acid) and saturated fatty acids, lauric acid (LA; dodecanoic acid), myristic acid (MA; tetradecanoic acid), and palmitic acid (PA; hexadecanoic acid), by means of differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). When the mixture was heated immediately after the solidification from the melt, the heat effect due to the gamma-to-alpha transformation of OA varied depending on the composition of the mixture. However, the mixture subjected to an annealing at the temperature slightly below the melting temperature provided the transformation at constant temperature which corresponds to the gamma-to-alpha transformation temperature of pure OA. This suggests that a solid phase formed by cooling of the melt of the mixture is not in an equilibrium state, but it relaxes to a stable solid during the annealing process. The T-X phase diagrams of these mixtures constructed from the DSC measurements demonstrate that the two fatty acid species are completely immiscible in a solid phase regardless of the type of polymorphs of OA, alpha- or gamma-form. According to a thermodynamic analysis of liquidus line basing on the regular solution model for the melt, the non-ideality of mixing tends to increase with the decrease in the acyl chain length of the saturated fatty acid, although the mixing is rather close to ideal.     

Transforming activity of the lymphotoxin-beta receptor revealed by expression screening

Pancreatic ductal carcinoma (PDC) remains one of the most intractable human malignancies. To obtain insight into the molecular pathogenesis of PDC, we constructed a retroviral cDNA expression library with total RNA isolated from the PDC cell line MiaPaCa-2. Screening of this library with the use of a focus formation assay with NIH 3T3 mouse fibroblasts resulted in the identification of 13 independent genes with transforming activity. One of the cDNAs thus identified encodes an NH(2)-terminally truncated form of the lymphotoxin-beta receptor (LTBR). The transforming activity of this short-type LTBR in 3T3 cells was confirmed by both an in vitro assay of cell growth in soft agar and an in vivo assay of tumorigenicity in nude mice. The full-length (wild-type) LTBR protein was also found to manifest similar transforming activity. These observations suggest that LTBR, which belongs to the tumor necrosis factor receptor superfamily of proteins, may contribute to human carcinogenesis.