Induction of TrkA receptor by retinoic acid in leukaemia cell lines

To explore the potential involvement of neurotrophins in the actions of retinoic acid (RA) on leukaemia differentiation, we examined the ability of RA to regulate the expression of neurotrophins and Trk receptors in several leukaemia cell lines. Expression of TrkA was dramatically induced by RA at both the mRNA and protein level in leukaemia cell lines K562 and KG-1. Furthermore, while no expression of trkB and trkC was detected, constitutive expression of nerve growth factor (NGF), neurotrophin-3 and neurotrophin-4/5 could be detected in leukemia cells. Our findings suggested that NGF/trkA may potentially be involved in the RA-induced differentiation of leukemia cells.

[Assay of terpenes in the leaves of Ginkgo biloba extract and its preparations by in situ fluorometric TLC]

A new TLC method for the assay of terpene lactones in Ginkgo biloba extract and its preparations has been established by means of optimized development condition and post-chromatographic thermal fluorescence derivatization. Satisfactory results can be obtained through polynomial regression calibration. The data obtained by this method have been proved ten times higher in sensitivity than those obtained by HPLC-refracto-detector.

Effect of pharyngeal water stimulation on esophageal peristalsis and bolus transport

Sensory stimuli originating from the pharynx inhibit esophageal peristalsis induced by a dry swallow. Our aims were to determine the effect of these stimuli on esophageal bolus transport and esophageal peristalsis induced by swallowing different volumes of liquid and semisolid boluses. We studied nine healthy volunteers age 35 +/- 4 yr in the supine position by intraluminal esophageal manometry as well as concurrent videofluoroscopy and manometry. In all subjects progression of peristalsis induced by swallowing of different volumes of water and mashed potato boluses was inhibited at all sites by pharyngeal water injection. Threshold volume for inhibition of the peristalsis induced by swallows of 5 and 10 ml of water was similar but significantly higher compared with dry swallows (P < 0.05). Pharyngeal water injection invariably halted transit of the barium boluses through the esophagus. Sensory impulses originating from the pharynx 1) inhibit esophageal bolus transit and 2) are capable of overcoming the facilitating effect of a liquid bolus on the swallowing apparatus. This phenomenon may explain the mechanism of some of the failed esophageal peristalsis observed in clinical practice.

Frequency of gastroesophageal reflux events induced by pharyngeal water stimulation in young and elderly subjects

Earlier studies have shown that isolated complete lower esophageal sphincter (LES) relaxation occurs as a result of pharyngeal water stimulation. Association of these relaxations with gastroesophageal reflux has not been studied systematically. Our aim was to determine this association in young and elderly subjects during precibal and postprandial periods. We studied 8 young subjects and 10 elderly subjects for 1 h before and 2 h after a 1,000-cal meal. In both groups, during the precibal period, negligible LES relaxation induced by pharyngeal water stimulation resulted in gastroesophageal reflux. In the postprandial period, gastroesophageal reflux events occurred after 16% of pharyngeal water injections in young subjects and after 44% in elderly subjects (P < 0.05). Intraabdominal length of the LES in elderly subjects was significantly shorter compared with younger subjects (P < 0.05). We conclude that gastroesophageal reflux events induced by pharyngeal water stimulation in the postprandial period are significantly increased compared with those of the precibal period and are significantly more prevalent in the elderly compared with the young. These differences seem to be associated with a significantly shorter intra-abdominal segment of the LES in the elderly.

Coordination of deglutitive glottal function and pharyngeal bolus transit during normal eating

BACKGROUND & AIMS

Deglutitive glottal function during the preparatory phase of swallowing and its coordination with bolus transit during normal eating are important for airway protection. The aim of this study was to examine this coordination during consumption of a normal meal.

METHODS

Fifteen healthy volunteers were studied using a videoendoscopic and videofluoroscopic technique.

RESULTS

A total of 207 liquid and 470 solid bolus swallows were analyzed. In 60% of liquid and 76% of solid food swallows, the bolus was seen in the pharynx before a swallow was initiated. Entry of boluses into the pharynx was associated with brief partial adduction of the vocal cords. Solid food entered and traversed the pharynx at the midline, whereas liquid bolus was split around the larynx and rejoined in the hypopharynx. Swallowing was initiated significantly earlier when bolus made contact with the upper third of the epiglottis compared with vallecula or pyriform sinuses.

CONCLUSIONS

In more than half of the instances, during normal eating, food enters the pharynx during the preparatory phase before a swallow is initiated, the path of pharyngeal transit of solid bolus is different from that of liquid bolus, and the epiglottal edge appears to be the most sensitive trigger zone for swallowing.

Spatial fidelity of image amplification in photorefractive crystals

We numerically studied the spatial fidelity of coherent image amplification by two-wave mixing configurations in photorefractive BaTiO(3):Ce using a three-dimensional analysis. The results are given for the case when the input one-dimensional rectangular amplitude of the image-bearing extraordinary beam is finite in the plane of incidence and when the amplitude is finite in the orthogonal plane. The fidelity and the gain versus the angle between the propagating direction of the image-bearing beam and the crystal c axis, the pump-to-image intensity ratio, and the input beamwidth, are analyzed.

IR circular dichroism of turns in small peptides

The observation of circular dichroism (CD) in vibrational transitions in the infrared spectral region offers new possibilities for the determination of peptide solution conformation. Infrared or vibrational CD (VCD) is a particularly sensitive probe for the conformation of various peptide turns. Results of small linear and cyclic peptides containing beta- or gamma-turns are reported.

Fanning effects in photorefractive crystals

A model to describe the fanning effect based on the beam-coupling mechanism in photorefractive crystals is presented. The intensity distribution of the fanning beam in a 45 degrees -cut BaTiO(3) crystal is measured experimentally. The results show good quantitative agreement with theory.

Visible cooperative upconversion laser in Er:LiYF(4)

We report trio upconversion laser action in Er:LiYF(4) with excitation at 1.55 microm resulting in cw emission at 0.55 microm to a temperature of 95 K and contrast its performance with earlier green erbium upconversion lasers.

Continuous-wave mode-locked visible upconversion laser

We describe continuous-wave mode locking and Q switching of an Er:LiYF(4) trio upconversion laser operating in the green spectral region.

Continuous-wave, pair-pumped laser

We report room-temperature operation of what we believe is the first continuous-wave laser that relies exclusively on cooperative upconversion by coupled ion pairs to achieve population inversion.

[Evaluation of radix Salviae Miltiorrhizae and its preparation]

Constituents of Radix Salviae Miltiorrhizae and its compound tablets, e.g. tanshinone A, cryptotanshinone, protocatechuic aldehyde and danshensu, were determined by TLC-densitometry. Optimum conditions were selected for constituent extraction, separation and determination. The method is accurate, sensitive and reproducible.