Effects of triolein or oleic acid on lymphatic recovery of docosahexaenoic acid given as ethyl ester and their intramolecular distribution in lymph triglyceride of rats

Effects of oleic acid or triolein on lymphatic recovery of docosahexaenoic acid (DHA) given as an ethyl ester were examined in rats with cannulated thoracic ducts. Lymphatic recovery of ethyl DHA given with oleic acid or triolein was significantly higher than in rats given ethyl DHA alone. DHA distrbuted almost exclusively at the 1-and 3-position of triglyceride in lymph collected at 0–3 h after the administration, when it was given with oleic acid or triolein. A small part of DHA distributed at the 2-position when ethyl DHA was the sole fatty acid given. Oleic acid given as free acid or triolein with ethyl DHA was a major fatty acid at the 2-position. Intramolecular distribution of DHA and oleic acid in lymph triglyceride was similar when ethyl DHA was given with oleic acid or triolein.     

Observation of ultrastructural changes in cultured retinal pigment epithelium following exposure to blue light

BACKGROUND: The retina can be damaged by light even when levels of energy are well below the threshold for thermal damage, and the experimental damage of the retinal pigment epithelium (RPE) may be induced more easily by blue light than by longer wavelengths of visible light. The present study demonstrates the ultrastructural damage produced by exposure to blue light in cultured RPE. METHODS: Long-Evans rats were enucleated 8-10 days after birth for primary culture. One week after seeding, the monolayer culture of RPE cells was exposed to a cool blue light (wavelength = 440 +/- 10 nm) for 36 h (12 h/day, 3 days) at 2.0 mW/cm2. Transmission electron microscopy was used to compare the exposed RPE with the control. The entire experiment was repeated 3 times independently. RESULTS: The cytoplasm of the exposed RPE exhibited degenerative changes, such as large whorls of membrane, lamellar whorls and whorled inclusions. CONCLUSION: The RPE cells can be damaged directly by blue light after excluding the possible influence of phagosomes. This primary culture of RPE can also serve as an in vitro model for the study of light damage to the RPE.     

M3-type muscarinic receptors predominantly mediate neurogenic quick contraction of bovine ciliary muscle

1. The present experiments were designed to investigate which subtypes of muscarinic receptors are involved in the neurogenic quick contraction of bovine ciliary muscle in connection to quick eye focal accommodation. 2. Transmural electrical stimulation (TES) produced a transient contraction, which was abolished in the presence of 3 x 10(-7) M tetrodotoxin and 10(-6) M atropine, but greatly augmented by 3 x 10(-7) M physostigmine. 3. The exogenously applied acetylcholine (ACh: 10(-9) to 3 x 10(-6) M) produced a concentration-dependent contraction, which was competitively antagonized by 10(-6) M atropine and augmented by 3 x 10(-7) M physostigmine, but unaffected by 3 x 10(-7) M tetrodotoxin. 4. The magnitude and time to peak of the maximal contraction produced by TES were significantly greater (1267.5 +/- 86.0 mg, P < 0.005) and shorter (9.0 +/- 0.2 sec, P < 0.005) than corresponding values (97.0 +/- 9.9 mg and 20.3 +/- 2.1 sec, respectively) of the phasic contraction caused by exogenously applied 10(-5) M ACh, at which concentration the agonist caused the maximal contraction. The velocity (140.6 +/- 7.8 mg/sec) of the transient contraction caused by TES was approximately 28-fold greater than that of the phasic contraction caused by ACh (5.1 +/- 0.9 mg/sec). 5. The contractions produced by TES were greatly attenuated by 4-diphenylacetoxy-N-methylpiperidine (4-DAMP) as an M3 antagonist and slightly by pirenzepine as an M1 antagonist (20.2 +/- 7.9% inhibition at the highest concentration), but not by methoctramine (MET) as an M2 antagonist. The IC50 value (-log M) for 4-DAMP was determined to be 7.17 +/- 0.14. 6. Scatchard plot analysis of [3H]-quinuclidinylbenzilate (QNB) binding revealed that the binding sites constituted a single population with a Kd of 31.2 +/- 0.8 pM and a Bmax of 895.5 +/- 93.2 fmol/mg protein. The activity in inhibiting [3H]-QNB binding was most potent with 4-DAMP (-log Ki = 7.98 +/- 0.02), but less potent with pirenzepine (-log Ki = 6.43 +/- 0.04) and MET (-log Ki = 7.32 +/- 0.16). 4-DAMP was approximately 35- and 5-fold more potent than pirenzepine and MET in terms of -log Ki values, respectively, suggesting the predominant localization of M3 receptor subtypes in the bovine ciliary muscle membrane. 7. These results suggest that TES produces a neurogenic quick contraction of the bovine ciliary muscle, which would be mediated mainly by ACh released from the intramural nerve terminals and subsequent excitation of M3 receptor subtypes localized on the ciliary muscle cells, and that neurogenic quick contraction of the ciliary muscle is possibly involved in part in eye focal accommodation.     

Improvements of morphologies and emission characteristics of highly purified organic oligomer semiconductors

We have purified oligomer semiconductors through vacuum sublimation and compared the film morphologies and the device performance of the purified materials with those of unpurified ones. We fabricated melt-molding films and thin film organic field-effect transistors (OFETs) using both the purified and unpurified oligomers. Comparing morphologies of the molten films we found regular arrangements of the crystal domains for the purified oligomers. Furthermore, the purified materials show definite light emission from the OFET devices.     

Ultrasensitive Imaging of Ca2+ Dynamics in Pancreatic Acinar Cells of Yellow Cameleon-Nano Transgenic Mice

Yellow Cameleons are genetically encoded Ca²⁺ indicators in which cyan and yellow fluorescent proteins and calmodulin work together as a fluorescence (Förster) resonance energy transfer Ca²⁺-sensor probe. To achieve ultrasensitive Ca²⁺ imaging for low resting Ca²⁺ or small Ca²⁺ transients in various organs, we generated a transgenic mouse line expressing the highest-sensitive genetically encoded Ca²⁺ indicator (Yellow Cameleon-Nano 15) in the whole body. We then focused on the mechanism of exocytotic events mediated by intracellular Ca²⁺ signaling in acinar cells of the mice with an agonist and observed them by two-photon excitation microscopy. In the results, two-photon excitation imaging of Yellow Cameleon-Nano 15 successfully visualized intracellular Ca²⁺ concentration under stimulation with the agonist at nanomolar levels. This is the first demonstration for application of genetically encoded Ca²⁺ indicators to pancreatic acinar cells. We also simultaneously observed exocytotic events and an intracellular Ca²⁺ concentration under in vivo condition. Yellow Cameleon-Nano 15 mice are healthy and no significant deteriorative effect was observed on physiological response regarding the pancreatic acinar cells. The dynamic range of 165% was calculated from R_max and R_min values under in vivo condition. The mice will be useful for ultrasensitive Ca²⁺ imaging in vivo.     

NMR studies of thermo-responsive behavior of an amphiphilic poly(asparagine) derivative in water

The thermo-responsive behavior of a unique biocompatible polymer, poly(N-substituted α/β-asparagine) derivative (PAD), has been studied with several NMR methods. The ¹H and ¹³C solution NMR measurements of the PAD in DMSO-d₆ were used to investigate the isolated polymer and perform spectral assignments. By systematic addition of D₂O we have tracked structural changes due to aggregation and observed contraction of hydrophilic side chains. Solution and cross polarization/magic angle spinning (CP/MAS) ¹³C NMR approaches were implemented to investigate the aggregates of the PAD aqueous solution during the liquid to gel transition as the temperature was increased. At temperatures near 20 °C, all of the peaks from the PAD were observed in the ¹³C CP/MAS and ¹³C solution NMR spectra, indicating the presence of polymer chain nodes. Increasing the temperature to 40 °C resulted in a partial disentanglement of the nodes due to thermal agitation and further heating resulted in little to no additional structural changes. Deuterium T₁–T₂ and T₂–T₂ two-dimensional relaxation spectroscopies using an inverse Laplace transform, were also implemented to monitor the water–PAD interaction during the phase transition. At temperatures near 20 °C the dynamical characteristics of water were manifested into one peak in the deuterium T₁–T₂ map. Increasing the temperature to 40 °C resulted in several distinguishable reservoirs of water with different dynamical characteristics. The observation of several reservoirs of water at the temperature of gel formation at 40 °C is consistent with a physical picture of a gel involving a network of interconnected polymer chains trapping a fluid. Further increase in temperature to 70 °C resulted in two non-exchanging water reservoirs probed by deuterium T₂–T₂ measurements.     

SERS microscopic imaging as novel tool for assessing viability and enumerating yeast cells at various stages of cell cycle in lag,log, exponential and stationary phases of growth in culture

Surface enhanced Raman scattering (SERS) microscopic imaging was employed to enumerate the yeast cells in culture. We found this imaging method as an efficient tool for easily differentiating and quantitatively enumerating yeast cell at different stages of cell-division cycle (G1, S, G2 and M phase) at various stages of growth phases namely lag, log, exponential and stationary phases in culture. Apart from enumerating the cells at different stages of cell cycle under lag, log, exponential and stationary phases, it was possible using SERS microscopy to differentiate the live cells from dead ones. The dead cells were SERS inactive and gave enhanced autofluorescence compared with the live cells, which were SERS active. The results from the present investigation suggest that SERS microscopic imaging, using silver nanoparticles (AgNPs) as a sensitive tool to enumerate the yeast cells in culture.