ICAM1 and fibrinogen-γ are increased in uterine epithelial cells at the time of implantation in rats

Uterine epithelial cells transform into a receptive state to adhere to an implanting blastocyst. Part of this transformation includes the apical concentration of cell adhesion molecules at the time of implantation. This study, for the first time, investigates the expression of ICAM1 and fibrinogen‐γ (FGG) in uterine epithelial cells during normal pregnancy, pseudopregnancy and in hormone‐treated rats. An increase (P < 0.05) in ICAM1 was seen at the apical membrane of uterine epithelial cells at the time of implantation compared with day 1 of pregnancy. ICAM1 was also increased (P < 0.05) on day 6 of pseudopregnancy as well as in ovariectomized rats treated with progesterone plus oestrogen. These results show that ICAM1 up‐regulation at the time of implantation is under the control of progesterone, and is not dependent on cytokine release from the blastocyst or in semen. FGG dimerization increased (P < 0.05) on day 6 of pregnancy compared with day 1, and was not up‐regulated in day 6 pseudopregnant animals, suggesting this increase is dependent on a developing blastocyst. The presence of ICAM1 and FGG in the uterine epithelium at the time of implantation in the rat is similar to that seen in lymphocyte–endothelium adhesion, and we suggest a similar mechanism in embryo–uterine epithelium adhesion is utilized. Mol. Reprod. Dev. 78:318–327, 2011. © 2011 Wiley‐Liss, Inc.     

Thermoresponsive heparin bioconjugate as novel aqueous antithrombogenic coating material

A novel thermoresponsive aqueous antithrombogenic coating material comprising a heparin bioconjugate with a six-branched, star-shaped poly(2-(dimethylaminoethyl)methacrylate) (6B-PDMAEMA), which has both thermoresponsive and cationic characters, was developed to reduce the thrombogenic potential of blood-contacting materials such as synthetic polymers or tissue-engineered tissues in cardiovascular devices. 6B-PDMAEMA with M(n) of ca. 24 kDa was designed as a prototype compound by initiator-transfer agent-terminator (iniferter)-based living radical photopolymerization from hexakis(N,N-diethyldithiocarbamylmethyl)benzene. Bioconjugation of heparin with 6B-PDMAEMA occurred as soon as both aqueous solutions were simply mixed to form particles. The particle size at 25 °C was less than several hundred nanometers in diameter under a heparin/6B-PDMAEMA mixing weight ratio of over 2.5. The particles were very stable because of the prevention of hydrolysis of 6B-PDMAEMA in its bioconjugated form. Because the lower critical solution temperature of the bioconjugate ranges from approximately 20 to 36 °C for the formation of microparticles, the coating could be done in an aqueous solution at low temperatures. The excellent adsorptivity and high durability of the coating above 37 °C was demonstrated on silicone and polyethylene films by surface chemical compositional analysis. Blood coagulation was significantly reduced on the bioconjugate-coated surfaces. Therefore, the thermoresponsive bioconjugate developed here appears to satisfy the initial requirements for a biocompatible aqueous coating material.     

Effects of changing illuminance on somatosensory function

Artificial sources of illumination can be easily used, regardless of the time and place, to improve visibility at night and in dark places. Illuminance and color temperature are particularly important factors since they are known to elicit physiological effects. However, the relationship between changes in illuminance and somatosensory function has not been sufficiently clarified. Thus, the purpose of this study was to construct a laboratorial model to examine the effects of lowering or raising illuminance on somatosensory function. Three illuminance levels (200 lx, 50 lx, and 0 lx), which were changed using all combinations, and an artificial sensory stimulus maintained at a constant intensity were presented to the subjects of this study. Objective sensory function in response to the sensory stimulus was investigated by somatosensory evoked potential (SEP), and subjective sensory evaluation in response to the stimulus was investigated using a visual analogue scale (VAS) and by interview. In many cases, the SEP amplitude and VAS value tended to decrease when illuminance was lowered and tended to increase when illuminance was raised. However, in a few cases, SEP amplitude and VAS value tended to increase in spite of the low illuminance. The occurrence of attention responses and unpleasant emotional responses caused by lowering the illuminance seems to be related to this study finding.     

Coating of a surface with 2-methacryloyloxyethyl phosphorylcholine (MPC) co-polymer significantly reduces retention of human pathogenic microorganisms

The present study compares the retention of four species that are often isolated in association with biomedical device-related infections - Staphylococcus aureus, Streptococcus mutans, Pseudomonas aeruginosa, and Candida albicans - to three different surfaces. All four bacterial species were found to bind significantly less well to MPC-coated surfaces than to non-coated surfaces. We attribute this effect to the "superhydrophilicity" of MPC-coated surfaces, whereas hydrophobic surfaces are well known to reduce bacterial retention and thus to inhibit a crucial step in the formation of bacterial biofilms that lead to biomedical device-related infections and complications.     

Rapid Ca2+-dependent increase in oxygen consumption by mitochondria in single mammalian central neurons

Oxygen consumption increases within a fraction of a second after the onset of neuronal activity, a phenomenon referred to as the "initial dip" in functional imaging studies of the living brain. The cellular mechanism that underlies this rapid increase in oxygen consumption has remained unclear, however. We have now used two-photon excitation imaging to characterize rapid activity-dependent mitochondrial responses in single neurons. This approach allowed simultaneous multicolor imaging of individual mitochondria in single mouse Purkinje neurons in culture. Mitochondrial depolarization was induced immediately when the cytosolic free Ca(2+) concentration ([Ca(2+)](i)) exceeded 15 microM and was associated with oxidation of mitochondrial NAD(P)H, suggesting that Ca(2+)-induced mitochondrial depolarization mediated by the Ca(2+) uniporter directly facilitated oxidation of NAD(P)H. With the use of a miniature oxygen electrode, we detected a burst of oxygen consumption within 0.2s after the onset of cell depolarization in single Purkinje neurons, and this rapid increase in oxygen consumption was dependent on the increase in [Ca(2+)](i). We have thus demonstrated a rapid Ca(2+)-dependent consumption of oxygen that is mediated by mitochondrial depolarization in mammalian central neurons. This process might function as a rapid feed-forward mechanism in homeostatic control of the cytosolic ATP concentration.     

The formation of Zn-Chl a in Chlorella heterotrophically grown in the dark with an excessive amount of Zn2+

Chlorella, when heterotrophically cultivated in the dark, is able to grow with Zn2+ at 10-40 mM, which is 10 times the concentration lethal to autotrophically grown cells. However, the lag phase is prolonged with increasing concentrations of Zn2+; for example, in this study, 1 d of the control lag phase was prolonged to about 16 d with Zn2+ at 16.7 mM (x2,000 of the control). Once the cells started to grow, the log phase was finished within 4-6 d regardless of Zn concentration, which was almost the same as that of the control. The photosysystem I reaction center chlorophyll, P700, and the far-red fluorescence were detected only after the late log phase of the growth curve, suggesting that chlorophyll-protein complexes can be organized after cell division has ceased. Interestingly, at more than 16.7 mM of Zn2+, Zn-chlorophyll a was accumulated and finally accounted for about 25% of the total chlorophyll a in the late stationary phase. We found that the Zn-chlorophyll a was present in the thylakoid membranes and not in the soluble fractions of the cells. The rather low fluorescence yield at around 680 nm in the stationary phase suggests that Zn-chlorophyll a can transfer its excitation energy to other chlorophylls. Before accumulation of Zn-chlorophyll a, a marked amount of pheophytin a was temporally accumulated, suggesting that Zn-chlorophyll a could be chemically synthesized via pheophytin a.     

Nicotine stimulates prolactin-releasing peptide (PrRP) cells and non-PrRP cells in the solitary nucleus

Nicotine has been reported to regulate food intake and body weight. But the mechanisms underlying these roles have not been fully elucidated. In the present study, we showed that acute administration of nicotine (0.5 mg/kg s.c.) could activate prolactin-releasing peptide (PrRP)-bearing neurons in the A2 area of the NTS of rats, suggesting that PrRP may be associated with nicotine-induced effects in the central nervous system (CNS). We next treated rats with nicotine chronically (4 mg/kg/day for 7 days i.p.), and the results showed that the body weight was strongly reduced and food intake was greatly suppressed compared to the vehicle control group (p<0.01). Immunocytochemical studies revealed that PrRP-bearing neurons in the NTS were evidently activated after chronic administration of nicotine, suggesting that PrRP was involved in the regulation of nicotine-mediated body weight loss and food intake suppression in rats. We also found that acute/chronic administration of nicotine activated PrRP-negative neurons in the NTS, and the majority of these neurons were shown to be TH-negative, suggesting that noncatecholaminergic, PrRP-negative neurons in the NTS are associated with the roles of nicotine. Nicotine has also been shown to stimulate the secretion of ACTH, a stress responsive hormone. In the present study, rats received nicotine (0.5 mg/kg s.c.) or saline followed by restraint stress for 30 min. The immunocytochemical results showed that nicotine/stress and saline/stress both activated the majority of the PrRP neurons in the NTS, there being no significant difference between the two treatments (p>0.05). Nicotine/stress also greatly activated PrRP/TH-negative neurons in the NTS. Saline/stress, however, caused much lower effect on the activation of PrRP/TH-negative neurons. In addition, the activation effect of nicotine/stress on PrRP/TH-negative neurons was much stronger than that of nicotine alone (p<0.01). These results indicated that PrRP was associated with stress responses, but it had little effect on nicotine-mediated stress responses. On the other hand, nicotine and restraint stress may synergistically activate PrRP/TH-negative neurons in the NTS. Taken together, our data show that PrRP is involved in the nicotine-induced regulation of body weight and food intake, but may not be involved in the mediation of nicotine on stress responses. PrRP/TH-negative neurons in the NTS are also associated with the roles of nicotine in the CNS.     

Identification of the pentapeptide constituting a dominant epitope common to all eukaryotic heat shock protein 90 molecular chaperones

We previously reported that, in human heat shock protein (Hsp) 90 (hHsp90), there are 4 highly immunogenic sites, designated sites Ia, Ib, Ic, and II. This study was performed to further characterize their epitopes and to identify the epitope that is potentially common to all members of the Hsp90 family. Panning of a bacterial library carrying randomized dodecapeptides revealed that Glu251-Ser-X-Asp254 constituted site Ia and Pro295-Ile-Trp-Thr-Arg299, site Ic. Site II (Asp701-Pro717) was composed of several epitopes. When 19 anti-hHsp90 monoclonal antibodies (mAbs) were subjected to immunoblotting against recombinant forms of 7 Hsp90-family members, 2 mAbs (K41110 and K41116C) that recognized site Ic bound to yeast Hsp90 with affinity identical to that for hHsp90, and 1 mAb (K3729) that recognized Glu222-Ala23, of hHsp90beta could bind to human 94-kDa glucose-regulated protein (Grp94), an endoplasmic reticulum paralog of Hsp90. Among the 5 amino acids constituting site Ic, Trp297 and Pro295 were essential for recognition by all anti-site-Ic mAbs, and Arg299 was important for most of them. The necessity of Ile296, Thr298, and Arg299, which are replaced by Leu, Met/Leu, and Lys, respectively, in some eukaryotic Hsp90, was dependent on the mAbs, and K41110 and K41116C could react with Hsp90s carrying these substitutions. From these data taken together, we propose that the pentapeptide Pro295-Ile-Trp-Thr-Arg299 of hHsp90 functions as an immunodominant epitope common to all eukaryotic Hsp90.     

Role of microtubules and centrosomes in the eccentric relocation of the germinal vesicle upon meiosis reinitiation in sea-cucumber oocytes

In the oocytes of many animals, the germinal vesicle (GV) relocates from the center to the periphery of the oocyte upon meiosis reinitiation, which is a prerequisite to the formation of meiotic spindles beneath the cell surface in order for meiosis to succeed. In the present study, we have investigated nuclear positioning using sea-cucumber oocytes. Upon meiosis reinitiation, the GV relocates to the cell periphery beneath a surface protuberance. After GV breakdown, polar bodies were extruded from the top of the protuberance, which we therefore called the animal pole process. The GV relocation was inhibited by nocodazole but not by cytochalasin. Immunofluorescent staining and electron microscopy of microtubular arrays revealed that: (i) in immature oocytes, two centrosomes were situated beneath the animal pole process far apart from the GV, anchoring to the cortex via astral microtubules; (ii) upon meiosis reinitiation, microtubular bundles were newly formed between the centrosomes and the GV; and (iii) the microtubular bundles became short as GV migration proceeded. These observations suggest that microtubules and centrosomes participate in GV relocation. A very large mass of annulate lamellae, having a 20-microm diameter, was found in the vegetal pole of the oocytes.