Effects of Different Light Sources on Neural Activity of the Paraventricular Nucleus in the Hypothalamus.

Background and Objectives: Physical function is influenced by light irradiation, and interest in the influence of light irradiation on health is high. Light signals are transmitted from the retina to the suprachiasmatic nucleus (SCN) via the retinal hypothalamic tract as non-image vision. Additionally, the SCN projects a nerve to the paraventricular nucleus (PVN) which acts as a stress center. This study examined the influences of three different light sources on neural activity in the PVN region using two different color temperatures. Materials and Methods: Experiments were conducted using twenty-eight Institute of Cancer Research (ICR) mice (10 week old males). Three light sources were used: (1) organic light-emitting diode (OLED) lighting, (2) LED lighting, and (3) fluorescent lighting. We examined the effects of light irradiation from the three light sources using two different color temperatures (2800 K and 4000 K). Perfusion was done 60 min after light irradiation, and then the brain was removed from the mouse for an immunohistochemistry analysis. c-Fos was immunohistochemically visualized as a marker of neural activity in the PVN region. Results: The number of c-Fos-positive cells was found to be significantly lower under OLED lighting and LED lighting conditions than under fluorescent lighting at a color temperature of 2800 K, and significantly lower under OLED lighting than LED lighting conditions at a color temperature of 4000 K. Conclusions: This study reveals that different light sources and color temperatures alter the neural activity of the PVN region. These results suggest that differences in the light source or color temperature may affect the stress response.

Initiation of Pharyngeal Response during Discrete Swallowing and Chew-swallowing in Healthy Subjects.

OBJECTIVE: The aim of this study was to measure the initiation of pharyngeal swallowing during discrete swallowing and during chew-swallowing in younger and older healthy subjects and to determine the normal range of the stage transition duration (STD) for different food boluses. The correlations between STDs were investigated. METHODS: Twenty-eight younger subjects (< 60 years old) and 25 older subjects (≥ 60 years old) were enrolled. While in the sitting position, the subjects swallowed 10 ml of thin liquid barium (LQ), 8 g of corned beef hash with barium (CB), 8 g of cookie with barium (CK), and a two-phase mixture of 4 g of corned beef hash with barium and 5 ml of thin liquid barium (MX). A videofluoroscopic examination of swallowing was performed at 30 frames/s in the lateral projection. The delay in pharyngeal swallowing (i.e., STD) was measured. The normal range (mean ± 2SD) of STDs for each bolus type was determined, and correlations were calculated to examine the relationship among STDs. RESULTS: The median STDs for LQ, CB, CK, and MX in all subjects were 0.0, 1.2, 2.4, and 1.9 s, respectively. The STDs were prolonged for CB, CK, and MX compared with LQ. Additionally, the median STD was longer for LQ, CB, and CK in older than in younger subjects. No significant correlations were found between STDs except for those between CB and CK. CONCLUSIONS: A delayed pharyngeal response is commonly observed during chew-swallowing. Liquids, solids, and two-phase mixtures exhibit independent timings of pharyngeal swallow initiation.

Isolated pharyngeal swallow exists during normal human feeding.

Swallowing is one of the basic activities in humans. The pharynx functions as an airway and a food channel, and a pharyngeal swallow usually occurs after bolus transport from the oral cavity. However, direct fluid infusion through a catheter into the hypopharynx produces a pharyngeal swallow without the oral stage in experimental situations. The purpose of this study was to examine whether a pharyngeal swallow, which is not accompanied by bolus transport, can occur during normal human feeding. Fifty-three healthy volunteers (25-89 years) were recorded, via videofluoroscopic examination of swallowing, during 3 different swallowing trials: command swallow of 10 ml liquid barium, chew-swallow of corned beef, and chew-swallow of a mixture of corned beef and liquid barium. Subsequently each swallow was classified as being either a consecutive pharyngeal swallow (CPS), following transport, or an isolated pharyngeal swallow (IPS), without immediately prior transport. The location of the bolus at swallow initiation was also noted. Of 307 trials, 681 swallows were identified, which included 43 IPS and 638 CPS. IPS only occurred as the first swallow of a trial, but the frequency of IPS did not differ between 28 younger (< 60 years) and 25 older (≥ 60 years) people. Of the three food types, IPS occurred more frequently with the mixed food than with liquid. These results suggest that IPS may represent an airway protective mechanism. In conclusion, IPS occurs in normal swallowing during a daily eating situation. Swallowing is more complex than a simple reflex.

Hyoid bone and larynx movements during electrical stimulation of motor points in laryngeal elevation muscles: a preliminary study.

OBJECTIVES: This study aimed to determine the laryngeal elevation muscle motor points, evaluate the movement of hyoid bone and larynx during stimulation of the motor points, and examine the potential for treating severe dysphagia by functional electrical stimulation. METHODS: The motor points of the laryngeal elevation muscles were anatomically determined from four cadavers. Those motor points in two healthy subjects and one lateral medullary syndrome patient were electrically stimulated by surface or implanted electrodes. RESULTS: The movements elicited by electrical stimulation of the motor points were greater in implanted than in surface electrodes. Elevation of the hyoid bone and the larynx in a lateral medullary syndrome patient were achieved with the implanted electrodes, but the upper esophageal sphincter opening was not obtained unless an additional cricopharyngeus muscle block was provided. CONCLUSION: The hyoid bone and larynx were elevated by electrically stimulating the motor points of the laryngeal elevation muscles.

Flux characteristics of cell culture medium in rectangular microchannels.

Rectangular microchannels 50 µm high and 30, 40, 50, 60, or 70 µm wide were fabricated by adjusting the width of a gap cut in a polyethylene sheet 50 µm thick and sandwiching the sheet between an acrylic plate and a glass plate. Flux in the microchannels was measured under three different inner surface conditions: uncoated, albumin-coated, and confluent growth of rat fibroblasts on the bottom of the microchannels. The normalized flux in microchannels with cultured fibroblasts or albumin coating was significantly larger than that in the uncoated channels. The experimental data for all microchannels deviated from that predicted by classical hydrodynamic theory. At small aspect ratio the flux in the microchannels was larger than that predicted theoretically, whereas it became smaller at large aspect ratio. The aspect ratio rather than Reynolds number is the correct property for predicting the variation of the normalized friction factor. We postulate that two counteracting effects, rotation of large molecules and slip velocity at the corners of the microchannels, are responsible for the deviation. From these results we conclude that albumin coating should be carried out in the same way as when fabricating our integrating cell-culture system. The outcomes of this study are not only important for the design of our culture system, but also quite informative for general microfluidics.

The risk of penetration or aspiration during videofluoroscopic examination of swallowing varies depending on food types.

Videofluoroscopic examination of swallowing (VF) is the gold standard in diagnosis and management of dysphagia. During VF, the patient ingests radiopaque foods and liquids, and oral, pharyngeal, and esophageal stages of swallowing physiology are observed and evaluated. Aspiration is defined as passage of materials through the vocal folds, and laryngeal penetration is defined as passage of materials into the larynx, but not through the vocal folds. In this study, we compared the risk of laryngeal penetration or aspiration during VF using various liquid volumes and food consistencies. Between January 2006 and September 2008, 229 patients with suspected dysphagia each were fed at least 2 out of 6 types of liquids or foods during VF in an upright posture without compensatory maneuvers. The 6 types were pudding-thick barium of 4 ml (PD), thin liquid barium of 4 ml (LQ4) and 10 ml (LQ10), one swallow of thin liquid barium from a cup (CUP), corned beef hash (8 g) with barium (CB), and a two-phase mixture of corned beef hash (4 g) with barium and thin liquid barium of 5 ml (MX). The paired comparisons revealed that laryngeal penetration risk increased in the following order: PD, CB, LQ4, LQ10, MX and CUP, while aspiration risk after PD increased in the following order: CB, LQ4, LQ10, CUP and MX. Thus, risk of laryngeal penetration or aspiration varies, depending on food types. In conclusion, risk of aspiration is highest with the two-phase food, and multi-textured foods should be used with caution in individuals with dysphagia.

Simple swallowing provocation test has limited applicability as a screening tool for detecting aspiration, silent aspiration, or penetration.

A number of tests for evaluating dysphagia without using videofluoroscopic examination of swallowing (VF) or videoendoscopic evaluation of swallowing (VE) have been developed. The simple swallowing provocation test (SSPT) is unique because it is performed while in a supine position and does not require the patient's cooperation. However, whether the SSPT detects aspiration or penetration correctly is unclear because its validity determined by VF or VE has not been evaluated. Therefore, we determined the sensitivity, specificity, and predictive accuracy of SSPT followed by VF in 45 patients. The sensitivities of the first-step and the second-step SSPT for the detection of aspiration, silent aspiration, or penetration were 72-75% and 13-17%, respectively; the specificities of the first-step and the second-step SSPT were 38-44% and 80-89%, respectively; and the predictive accuracies of the first-step and the second-step SSPT were 58-67% and 31-49%, respectively. These data suggest that SSPT has limited applicability as a screening tool for aspiration, silent aspiration, or penetration because of its low sensitivity. This test may be useful for patients who cannot undergo other tests due to cognitive and/or linguistic dysfunction.

Effects of dental treatment on the quality of life and activities of daily living in institutionalized elderly in Japan.

Impairment of oral health has a negative impact on the quality of life (QOL) of the elderly. Activities of daily living (ADL) are known to be an important determinant of their QOL. A controlled study was conducted between September and November 2007 to determine the effects of dental treatments on the QOL and ADL among 30 institutionalized Japanese elderly who were allocated into two groups, an intervention group and a control group. Their mean age was 80+/-9 years. Outcome data were collected 6 weeks after baseline in both groups. QOL and ADL were assessed using General Oral Health Assessment Index (GOHAI) and Functional Independence Measure (FIM). The intervention group, which had received dental treatment, showed significant increases in GOHAI scores between baseline and 6 weeks (p=0.04), whereas no significant difference was found between baseline and 6 weeks in the control group. The differences in the changes in the FIM scores for expression were significant in the model adjusted for covariables (p=0.03). Our findings showed that dental treatments increased the oral health-related QOL and the expression function in the ADL. Promoting dental care service at nursing facilities may be beneficial for maintaining the residents' QOL.

Hyoid movement and laryngeal penetration during sequential swallowing.

This study examined hyoid movement during sequential swallowing and evaluated the relationship among trajectory patterns, swallowing types based on laryngeal movement and laryngeal penetration. Twelve healthy adults underwent videofluorography during sequential swallowing. Each swallow was classified into two types: opened laryngeal vestibule after swallow (i-Segmental type) and closed laryngeal vestibule after swallow (i-Continuous type). Each participant's swallowing type was classified by the same method. We analyzed two-dimensional movements of the hyoid, and the trajectories were classified into three patterns: hyoid moved in the anterosuperior direction after the onset of swallow (pattern L); hyoid moved in the anterosuperior direction after the onset of swallow, beyond the mandibular plane (pattern X); and the hyoid was above the mandibular plane at the onset of swallow, and then it moved in the inferior direction (pattern U). Two-way ANOVA revealed that there was a significant interaction between the swallowing type and trajectory pattern, and laryngeal penetration was the highest for the combination of individual swallow of i-Continuous type and pattern L. In sequential swallowing, the existence of a penetration-prone swallowing pattern combination was an interesting phenomenon relevant to eating management for dysphagic patients; however further study in patient groups is required.

What is the chin-down posture? A questionnaire survey of speech language pathologists in Japan and the United States.

The "chin-down" or "chin-tuck" maneuver is a postural technique widely used in dysphagia treatment. The posture, however, does not have a precise anatomical definition. We studied the current practice of 42 speech-language pathologists (SLPs) in Japan and the U.S. with a questionnaire survey regarding the chin-down posture. The main findings were that (1) three of five of the pictures were selected by respondents both in Japan and in the U.S. as depicting the chin-down posture; (2) 23% of Japanese and 58% of the U.S. SLPs made a distinction between chin down and chin tuck; and (3) the use of anatomical terminology by SLPs differed between the two countries. This study showed that there is poor agreement among SLPs about the meaning of the chin-down and chin-tuck postures. Developing a precise definition is important because various postures may have differing physiologic effects.