Infrared spectroscopy of human tissue. I. Differentiation and maturation of epithelial cells in the human cervix

Infrared spectral results for the different epithelial layers of human cervical squamous tissue are reported. The layers, representing different cellular maturation stages, exhibit quite different spectral patterns. Thus, infrared spectroscopy presents a powerful tool to monitor cell maturation and differentiation. Furthermore, a detailed understanding of the spectra of the individual layers of tissue permit a proper interpretation of the state of health of cells exfoliated from such tissue. Part II of this series describes the use of the spectral information presented here to interpret the infrared spectra of exfoliated cells.

Infrared spectroscopy of human tissue. II. A comparative study of spectra of biopsies of cervical squamous epithelium and of exfoliated cervical cells

A comparison of infrared absorption spectra obtained from the different layers of squamous epithelium from the human cervix, and infrared spectra obtained from exfoliated cervical cells, is presented. Infrared spectroscopy has been shown (in part I of this series) to be a sensitive tool to monitor maturation and differentiation of human cervical cells; therefore, this spectroscopic technique provides new insights into the composition and state of health of exfoliated cells.

Infrared spectroscopy of human tissue. IV. Detection of dysplastic and neoplastic changes of human cervical tissue via infrared microscopy

Infrared absorption spectra of formalin-fixed, paraffin-embedded human cervical tissue are reported for normal, dysplastic and neoplastic samples. The spectral differences found in this study between these states of the tissues are far less than those observed for single cells by us and others. Nevertheless, we find a direct correspondence between spectral data from tissue sections, obtained from biopsies, and individual exfoliated cells, typically obtained during a pap procedure. We also find that spectra due to dysplastic samples fall about halfway between the spectral features of normal and cancerous samples.

[Sequence variability in Borna disease virus ORF II from human beings]

40 clones from five psychiatric patients and three healthy blood donors in whom Borna disease virus (BDV) ORF II fragments in PBMC were previously proved by nested RT-PCR were sequenced and compared with BDV/MDCK. There were eleven point mutations in all clones compared with reported HE80-1, but no difference between human and BDV/MDCK clones. We found specific sequence variability at nt 1701 in ten clones from two psychiatric disorder patients (T-->C) and at nt 1696 in fifteen clones from three healthy blood donors (A-->T). This result strongly suggests there are some special gene divergence in BDV derived from human beings.

[The structure correction of villosolside]

The crystal structure of villosolside was determined by X-ray diffraction, which led to some stereochemical amendment of the structure proposed in the article by Xu CJ et al. in Acta Pharm Sin 1985, 20:652.

Characterization of the pharyngo-UES contractile reflex in humans

Preliminary human studies suggest the presence of an upper esophageal sphincter (UES) contractile reflex triggered by pharyngeal water stimulation. The purposes of this study were to further characterize this reflex and determine the threshold volume for its activation. We studied 10 healthy young volunteers by manometric technique before and after topical pharyngeal anesthesia. UES pressure responses to various volumes and temperatures of water injected into the pharynx were elucidated. At a threshold volume, rapid-pulse and slow continuous pharyngeal water injection resulted in significant augmentation of UES pressure in all volunteers. Threshold volume for inducing UES contraction averaged 0.1 +/- 0.01 ml for rapid-pulse injection and was significantly smaller than that for slow continuous injection (1.0 +/- 0.2 ml). UES pressure increase duration averaged 16 +/- 4 s. Augmentation of UES resting tone by injection of water with three different temperatures was similar. This augmentation was abolished after topical anesthesia. Conclusions were that stimulation of the human pharynx by injection of minute amounts of water results in a significant increase in resting UES pressure: the pharyngo-UES contractile reflex. The magnitude of pressure increase due to activation of this reflex is not volume or temperature dependent. Loss of pharyngeal sensation abolishes this reflex.

X-ray structure of human class IV sigmasigma alcohol dehydrogenase. Structural basis for substrate specificity

The structural determinants of substrate recognition in the human class IV, or sigmasigma, alcohol dehydrogenase (ADH) isoenzyme were examined through x-ray crystallography and site-directed mutagenesis. The crystal structure of sigmasigma ADH complexed with NAD+ and acetate was solved to 3-A resolution. The human beta1beta1 and sigmasigma ADH isoenzymes share 69% sequence identity and exhibit dramatically different kinetic properties. Differences in the amino acids at positions 57, 116, 141, 309, and 317 create a different topology within the sigmasigma substrate-binding pocket, relative to the beta1beta1 isoenzyme. The nicotinamide ring of the NAD(H) molecule, in the sigmasigma structure, appears to be twisted relative to its position in the beta1beta1 isoenzyme. In conjunction with movements of Thr-48 and Phe-93, this twist widens the substrate pocket in the vicinity of the catalytic zinc and may contribute to this isoenzyme's high Km for small substrates. The presence of Met-57, Met-141, and Phe-309 narrow the middle region of the sigmasigma substrate pocket and may explain the substantially decreased Km values with increased chain length of substrates in sigmasigma ADH. The kinetic properties of a mutant sigmasigma enzyme (sigma309L317A) suggest that widening the middle region of the substrate pocket increases Km by weakening the interactions between the enzyme and smaller substrates while not affecting the binding of longer alcohols, such as hexanol and retinol.

Structure of mitochondrial aldehyde dehydrogenase: the genetic component of ethanol aversion

BACKGROUND

The single genetic factor most strongly correlated with reduced alcohol consumption and incidence of alcoholism is a naturally occurring variant of mitochondrial aldehyde dehydrogenase (ALDH2). This variant contains a glutamate to lysine substitution at position 487 (E487K). The E487K variant of ALDH2 is found in approximately 50% of the Asian population, and is associated with a phenotypic loss of ALDH2 activity in both heterozygotes and homozygotes. ALDH2-deficient individuals exhibit an averse response to ethanol consumption, which is probably caused by elevated levels of blood acetaldehyde. The structure of ALDH2 is important for the elucidation of its catalytic mechanism, to gain a clear understanding of the contribution of ALDH2 to the genetic component of alcoholism and for the development of specific ALDH2 inhibitors as potential drugs for use in the treatment of alcoholism.

RESULTS

The X-ray structure of bovine ALDH2 has been solved to 2.65 A in its free form and to 2.75 A in a complex with NAD+. The enzyme structure contains three domains; two dinucleotide-binding domains and a small three-stranded beta-sheet domain, which is involved in subunit interactions in this tetrameric enzyme. The E487K mutation occurs in this small oligomerization domain and is located at a key interface between subunits immediately below the active site of another monomer. The active site of ALDH2 is divided into two halves by the nicotinamide ring of NAD+. Adjacent to the A-side (Pro-R) of the nicotinamide ring is a cluster of three cysteines (Cys301, Cys302 and Cys303) and adjacent to the B-side (Pro-S) are Thr244, Glu268, Glu476 and an ordered water molecule bound to Thr244 and Glu476.

CONCLUSIONS

Although there is a recognizable Rossmann-type fold, the coenzyme-binding region of ALDH2 binds NAD+ in a manner not seen in other NAD+-binding enzymes. The positions of the residues near the nicotinamide ring of NAD+ suggest a chemical mechanism whereby Glu268 functions as a general base through a bound water molecule. The sidechain amide nitrogen of Asn169 and the peptide nitrogen of Cys302 are in position to stabilize the oxyanion present in the tetrahedral transition state prior to hydride transfer. The functional importance of residue Glu487 now appears to be due to indirect interactions of this residue with the substrate-binding site via Arg264 and Arg475.

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.