Perceived general health in relation to oral health status in a rural Kenyan elderly population.

BACKGROUND: This study aimed to determine the present oral health status of the rural Kenyan elderly population and to investigate whether oral health status is associated with the perceived general health. METHODS: A total of 131 individuals aged 65 years and over in Mbita Constituency, Homa Bay County in Kenya were randomly selected and visited at home. The home visit study, which was conducted from 2014 to 2016, included oral examination by a dentist and administration of a self-reporting questionnaire. The number of teeth present and functional tooth unit (FTU) points were calculated using the dental chart. Perceived general health, subjective masticatory ability, and self-reported periodontal symptoms were collected using a questionnaire sheet. Fisher's exact test and nonparametric test were used to determine the difference in percentage and means. The odds ratio of good general health based on the participants' masticatory satisfaction was calculated by logistic analysis. RESULTS: Satisfactory mastication was dependent on the number of teeth present, FTU points, and self-reported "gum bleeding" and "tooth mobility". Furthermore, satisfactory mastication was associated with perceived general health status independent of sex and age. The adjusted odds ratio of good perceived general health was 2.29 (95% confidence interval 1.05-4.99) for participants who had the subjective masticatory ability. CONCLUSION: Among the Kenyan elderly population, satisfactory mastication was related to the number of teeth present, FTU points, and self-reported periodontal symptoms. Furthermore, satisfactory mastication was associated with perceived general health status independently.

Age Differences in Naloxone Reversibility of Electroacupuncture on the Jaw Opening Reflex in Rats.

Background: Electroacupuncture is one of the most popular physical treatments for clinical pain, but the potential influence of a patient's age on the effectiveness of electroacupuncture treatment has not been clearly established. Objectives: The present study aimed to detect a potential difference in electroacupuncture- induced analgesia between juvenile and adult rats. Methods: In this study, we investigated the effects of electroacupuncture treatment on the nociceptive jaw-opening reflex evoked by tooth-pulp stimulation in juvenile and adult rats. Results: Our results showed there were age differences in electroacupuncture-induced analgesic effects in rats, especially with naloxone antagonization. The ratio of naloxonereversibility against electroacupuncture analgesia was greater in adult rats than in juvenile rats. Conclusion: These results suggest that electroacupuncture analgesia is produced mainly by the non-opioid system in juvenile rats and by the opioid system in adult rats.

SURVEY OF DENTAL STUDENTS' ATTITUDE REGARDING ORIENTAL MEDICINE/COMPLEMENTARY AND ALTERNATIVE MEDICINE: COMPARISON BETWEEN TWO JAPANESE DENTAL SCHOOLS.

BACKGROUND: The present study aimed to examine the impact of "curricula for undergraduate education in oriental medicine (OM)/complementary and alternative medicine (CAM)" on student awareness of OM. A questionnaire survey was conducted involving the Nagasaki University School of Dentistry (NUSD), a university that implements education in OM as part of its undergraduate curriculum, and Tokyo Dental College (TDC), which does not teach OM. MATERIALS AND METHODS: The third- and fifth-year students of both NUSD and TDC underwent the anonymous questionnaire survey, which included questions regarding their knowledge of OM and CAM, interests in these subjects, and their opinions on the necessity of teaching OM in the undergraduate dental education, and the results were collected for analysis. RESULTS: Whereas 33% of 5th year NUSD students had knowledge of OM/CAM was 33%, only 10% of 5th year TDC students reported knowledge on the subject. 69% of 5th year NUSD students interested in OM/CAM, while 5th year TDC students who interest them were only 45%. Although 77% of 5th year NUSD students were in favor of OM education implemented in the Faculty of Dentistry, the percentages of TDC students of that were smaller (46% in 3rd year and 48% in 5th year). Whereas 26% of 5th year TDC students did not recognize the necessity of oriental medicine education, only one 5th year NUSD student (2%) did not so. CONCLUSION: Introduction of education in OM in the undergraduate dental education program helps students to increase their interests in dental clinical applications.

Functional effects of cold stimulation on taste perception in humans.

Thermal modulation of signaling pathways leads to excitation of taste receptor cells, but the underlying mechanisms remain unclear. Furthermore, it has long been known that there are contrast effects in various senses. In this study, we investigated cold-taste contrast and the relationship between taste and somatosensation. We lowered intraoral temperature using cold stimulus as a pretreatment, then returned to normal temperature in 249 healthy subjects, before administering room temperature taste-stimulating solutions to investigate changes in sensitivity to the four basic tastes (Sweet, Salt, Sour, and Bitter). Statistical comparisons of taste recognition thresholds before and after cold stimulus showed increased taste sensitivity for all four basic tastes. After categorizing different levels of pre-cold stimulus taste sensitivity into groups and comparing changes in sensitivity to the four basic tastes before and after stimulus, we found that the lower the sensitivity to the four basic tastes, the greater the increase in sensitivity induced by cold stimulus. These findings suggest that taste and low temperature send afferent signals which cause interaction in the afferent pathways between the peripheral and central nervous systems. Cold stimulus may offer one possible treatment strategy for dysgeusia.

Carbenoxolone-sensitive and cesium-permeable potassium channel in the rod cells of frog taste discs.

The rod cells in frog taste discs display the outward current and maintain the negative resting potential in the condition where internal K+ is replaced with Cs+. We analyzed the properties of the Cs+-permeable conductance in the rod cells. The current-voltage (I/V) relationships obtained by a voltage ramp were bell-shaped under Cs+ internal solution. The steady state I/V relationships elicited by voltage steps also displayed the bell-shaped outward current. The activation of the current accelerated with the depolarization and the inactivation appeared at positive voltage. The gating for the current was maintained even at symmetric condition (Cs+ external and internal solutions). The wing cells did not show the properties. The permeability for K+ was a little larger than that for Cs+. Internal Na+ and NMDG+ could not induce the bell-shaped outward current. Carbenoxolone inhibited the bell-shaped outward Cs+ current dose dependently (IC50 : 27 µM). Internal arachidonic acid (20 µM) did not induce the linear current-voltage (I-V) relationship which is observed in two-pore domain K+ channel (K2P). The results suggest that the resting membrane potentials in the rod cells are maintained by the voltage-gated K+ channels.

Neuronal Activity in the Subthalamic Cerebrovasodilator Area under Partial-Gravity Conditions in Rats.

The reduced-gravity environment in space is known to cause an upward shift in body fluids and thus require cardiovascular adaptations in astronauts. In this study, we recorded in rats the neuronal activity in the subthalamic cerebrovasodilator area (SVA), a key area that controls cerebral blood flow (CBF), in response to partial gravity. "Partial gravity" is the term that defines the reduced-gravity levels between 1 g (the unit gravity acceleration on Earth) and 0 g (complete weightlessness in space). Neuronal activity was recorded telemetrically through chronically implanted microelectrodes in freely moving rats. Graded levels of partial gravity from 0.4 g to 0.01 g were generated by customized parabolic-flight maneuvers. Electrophysiological signals in each partial-gravity phase were compared to those of the preceding 1 g level-flight. As a result, SVA neuronal activity was significantly inhibited by the partial-gravity levels of 0.15 g and lower, but not by 0.2 g and higher. Gravity levels between 0.2-0.15 g could represent a critical threshold for the inhibition of neurons in the rat SVA. The lunar gravity (0.16 g) might thus trigger neurogenic mechanisms of CBF control. This is the first study to examine brain electrophysiology with partial gravity as an experimental parameter.

Suppressive effects of D-glucosamine on the 5-HT sensitive nociceptive units in the rat tooth pulpal nerve.

It is well known that D-glucosamine hydrochloride (DGL) has a variety of biological activities and is regarded as a nutritional supplement effective in improving various disorders, including osteoarthritis and atherosclerosis. Although it has been reported that DGL has a significant pain relief effect in treating osteoarthritis, little is known about the characteristics of the effects of this compound on dental pain. The present study was undertaken to evaluate the applicability of DGL as a medicament to control pulpalgia. Using an in vitro rat mandible-inferior alveolar nerve preparation (jaw-nerve preparation), we evaluated the effects of DGL on 5-hydroxytryptamine (5-HT) sensitive nociceptive responses in the tooth pulpal nerve. 5-HT-induced nociceptive responses were fairly suppressed by direct application of DGL, suggesting that DGL have a pain relief effect on patients with dental pain.

Comparison of stress-induced modulation of smooth-muscle activity between ileum and colon in male rats.

Stress is a well-known cause of numerous digestive conditions, including gastrointestinal-function disorders. The autonomic nervous system regulates intestinal movements via cholinergic and adrenergic efferent fibers; however it is not clear how stress could affect these control mechanisms and in particular whether in a site-dependent manner. In this study we tested in vitro the effects of topical application of acetylcholine (Ach) and adrenalin (Adr) on smooth-muscle contractions of intestinal segments isolated from stress-conditioned rats. Stress was loaded by hypergravity stimulation (10min/day) for periods of 1, 6 or 30days. As a result, stress-conditioning affected intestinal sensitivity to Ach and Adr differently at sections of the ileum and colon. In the ileum no significant differences were found between control and stress-conditioned rats, whereas in the colon, samples from 6- and 30-day stress-conditioned rats showed larger amplitudes of Ach-induced contraction, as well as greater antagonization by Adr application. These results suggest that stress conditioning can modify autonomic control of intestinal movements by altering smooth-muscle sensitivity to Ach and Adr.

Clinical correlates of anhedonia in patients with Parkinson's disease.

OBJECTIVE: To investigate the prevalence and clinical correlates of anhedonia in patients with Parkinson's disease (PD) and to also examine the relationship between anhedonia and the QOL. METHODS: One hundred and seventeen patients with PD completed the Snaith-Hamilton Pleasure Scale (SHAPS), the State-Trait Anxiety Inventory (STAI), the Beck Depression Inventory Second Edition (BDI-II), Starkstein's Apathy Scale (AS) and a quality of life (QOL) battery. Hoehn and Yahr (HY) staging, the Unified Parkinson's Disease Rating Scale (UPDRS) and the Mini-Mental State Examination (MMSE) were administered on the same day. RESULTS: Anhedonia (SHAPS score≥3) was diagnosed in 15% of the patients. The SHAPS score was found to be significantly correlated with the HY stage and the UPDRS (I, IVB, IVC, total), BDI-II, AS and STAI (State, Trait) scores. A multivariate analysis revealed that the BDI-II and STAI (Trait) scores significantly influenced the SHAPS scores. The SHAPS scores were found to be negatively correlated with the QOL. CONCLUSIONS: These findings indicate that anhedonia is associated with depression and anxiety. In addition, recognizing anhedonia in patients with PD is important since it may have a negative effect on the QOL.

Stress-induced modulation of nociceptive responses in the rat anterior cingulate cortex.

In the limbic system, the anterior cingulate cortex (ACCX) is one of the key areas involved in the close association between pain and emotion. However, neuronal changes in ACCX nociceptive responses after stress conditioning have not yet been quantitatively investigated. We investigated the modulation of nociceptive responses in the ACCX neurons following restraint stress in rats. The present study demonstrated that stress-conditioning enhanced excitatory nociceptive responses in the ACCX following tail stimuli in the mid-term (7 days). Short-term (3 days) and long-term (21 days) of stress conditioning did not affect these responses significantly. Nociceptive responses evoked by other sites of the body (nose, back and four paws) stimulation were not changed by stress-conditioning, indicating that neural information from the tail is important for emotional system modulation. It is suggested that the emotional/affective part of the pain sensation is strongly modified by stress through neuroplasticity in the ACCX.

Wing (Ib) cells in frog taste discs detect dietary unsaturated fatty acids.

The effects of unsaturated fatty acids on membrane properties were studied using conventional whole-cell patch-clamp recording of isolated wing (Ib) cells in bullfrog (Lithobates catesbeianus) taste discs. Applying arachidonic acid to the bath induced monophasic inward currents in 60% of wing cells and biphasic inward and outward currents in the other cells. The intracellular dialysis of arachidonic acid did not induce an inward current; however, it enhanced a slowly developing Ba(2+)-sensitive outward current. The effects of various unsaturated fatty acids were explored under the condition of Cs(+) internal solution. Linoleic and α-linolenic acids induced large inward currents. Oleic, eicosapentaenoic and docosahexaenoic acids elicited the same inward currents as those of arachidonic acid. Wing cells, under the basal condition with Cs(+) internal solution, displayed a small inward current of -1.1±0.1pA/pF at -50mV (n=40), in which the peak existed at a membrane potential of -49mV. Removing external Ca(2+) further increased the inward current by -2.9±0.3pA/pF at -50mV (n=4) from the basal current and the peak was located at -55mV. External linoleic acid (50µM) also induced a similar inward current of -5.6±0.6pA/pF at -50mV (n=19) from the basal current and the peak was located at -61mV. External Ca(2+)-free saline and linoleic acid induced similar current/voltage (I/V) relationships elicited by a ramp voltage as well as voltage steps. Linoleic acid-induced currents were not influenced by replacing internal EGTA with BAPTA, whereas inward currents disappeared under the elimination of external Na(+) and addition of flufenamic acid. These results suggest that dietary unsaturated fatty acids may depolarize wing (Ib) cells, which affects the excitability of these cells.

Anxiety and depression in patients with Parkinson's disease.

OBJECTIVE: To investigate the prevalence and clinical correlates of anxiety and depression in patients with Parkinson's disease (PD) and to examine the relationship between anxiety and depression and the quality of life (QOL). METHODS: One hundred and seventeen patients with PD completed the state-trait anxiety inventory (STAI), the beck depression inventory second edition (BDI-II), Starkstein's apathy scale (AS) and QOL battery. Hoehn and Yahr (HY) staging, the unified Parkinson's disease rating scale (UPDRS) and the mini-mental state examination (MMSE) were administered on the same day. RESULTS: Anxiety (STAI score ≥41 for men or ≥42 for women) was diagnosed in 55% of the patients and depression (BDI-II score ≥14) was diagnosed in 56% of the patients. Anxiety coexisted with depression in 41% of the patients, while depression without anxiety was observed in 15% of the patients and anxiety without depression was observed in 14% of the patients. The STAI score was found to be significantly correlated with the UPDRS (I, IV) and AS scores, whereas the BDI-II score was found to correlate with the HY stage and the UPDRS (I, III, IV) and AS scores. Both the STAI and BDI-II scores were found to negatively correlate with QOL. A multivariate analysis revealed that depression and anxiety are similarly associated with the PD specific QOL (PDQ-39), while motor severity, as judged by the HY stage and UPDRS III score, is not. CONCLUSION: These findings indicate that recognizing anxiety and depression in patients with PD is important, since both conditions are commonly observed in patients with PD and are similarly associated with the QOL, independent of motor severity.

Behavioral responses to partial-gravity conditions in rats.

The effects of microgravity or hypergravity on living organisms have been studied extensively; however, thus far no studies have addressed the effects of "partial-gravity", that is, the low-gravity levels between the unit gravity (1G) on Earth and zero gravity (0 G) in space. The purpose of the present study was to examine behavioral responses in rats under partial-gravity conditions. Rat behavior was monitored by video cameras during parabolic flights. The flight trajectory was customized in order to generate graded levels of partial gravity. Gravity-dependent behavior patterns were observed in rats. In the conditions of 0.4 G through 0.2G, rats showed startle and crouching. Hindlimb stretching emerged at 0.15 G and was more frequently observed toward 0.01 G. Different thresholds may exist for emotional and balance/posture-related behaviors.

Receptive field characteristics of stretch-insensitive mechanosensitive units in the rat urinary bladder.

INTRODUCTION: The pelvic, hypogastric and pudendal nerves carry sensory information from the urinary bladder. The pelvic nerve is reported to be the most important one of these afferent nerves in producing urinary bladder sensation. The primary types of mechanoreceptors in the bladder can be divided into stretch-sensitive and stretch-insensitive units. The former is considered to be more important in producing bladder sensation. However, little is known about the precise receptive field properties of the stretch-insensitive mechanoreceptors in the urinary bladder. Therefore, in this study, we systematically investigated the receptive field characteristics of the pelvic single unit innervating the rat bladder wall. MATERIALS AND METHODS: Functional single unit recordings were made from the pelvic nerve afferent filaments of anesthetized rats. A von Frey device was used for quantitative mechanical stimulation of the bladder surface. In addition, electrical stimulation was used for estimating conduction velocities of the nerve fibers in the receptive field. RESULTS: The threshold value for mechanical stimulation was statistically lower at the caudal portion of the bladder body (sites IV and V) than the other bladder sites. The bladder neck (site I) had the highest mechanical stimulation threshold value for the bladder stretch-insensitive mechanoreceptors. In most cases, the pelvic nerve had bilateral receptive fields. The majority of the pelvic nerve afferents had conduction velocities in the slow A-δ or C fiber range. Mechanical stimulation threshold values were higher in males than in females in a portion of the bladder sites. DISCUSSION: The pelvic stretch-insensitive bladder mechanoreceptors are 1) higher threshold at the bladder base, 2) contain large bilateral receptive fields and 3) demonstrate relatively slow conduction velocities. These characteristics indicate a non-uniform distribution of stretch-insensitive mechanoreceptors in the rat urinary bladder wall.

Hypergravity conditioning on ileal movements in rats.

INTRODUCTION: Stress is a common trigger for various physiological disturbances, including feeding disorders. One of the possible mechanisms for feeding disorders may be linked to changes in intestinal movement caused by stress. Therefore, here we investigated in vitro stress-induced changes in ileal movement. METHODS: Rats (female Wistar, SPF) were divided into Control (1 G) and hypergravity (hyperG) groups. HyperG stress was applied daily for 10 min by a centrifugal apparatus for 1 to 30 d. Under barbiturate anesthesia, a 1-cm long section of the ileum was isolated and fixed in a Magnus-type chamber filled with tyrode solution. Intestinal movement was evoked by applying acetylcholine (Ach, 10(-7)-10(-5) g x ml(-1)). Antagonistic effects of adrenalin (Adr, 10(-4) g x ml(-1)) on the Ach-evoked movements were also observed. RESULTS: Clear ileum movements were observed after Ach application. The movement pattern was phasic (early) and tonic (late). Peak amplitude of the phasic wave was dose-dependent on the Ach concentration. No significant differences in the averaged peak amplitude between control and hyperG groups were observed. The peak amplitude was decreased by Adr application in both the control and hyperG groups; however, the degree of the decrement was higher in hyperG than in control at 1 d after stress loading. DISCUSSION: The present study indicates that gravity stress modified ileal movement. Although basic ileum movements evoked by Ach were not influenced by stress, they were modified by Adr at a quite early stage after stress loading, suggesting an increase in the sensitivity of Adr receptors, but not of Ach receptors in the ileum.

Efferent fibers innervate gustatory and mechanosensitive afferent fibers in frog fungiform papillae.

A possibility of efferent innervation of gustatory and mechanosensitive afferent fiber endings was studied in frog fungiform papillae with a suction electrode. The amplitude of antidromic impulses in a papillary afferent fiber induced by antidromically stimulating an afferent fiber of glossopharyngeal nerve (GPN) with low voltage pulses was inhibited for 40 s after the parasympathetic efferent fibers of GPN were stimulated orthodromically with high voltage pulses at 30 Hz for 10 s. This implies that electrical positivity of the outer surface of papillary afferent membrane was reduced by the efferent fiber-induced excitatory postsynaptic potential. The inhibition of afferent responses in the papillae was blocked by substance P receptor blocker, L-703,606, indicating that substance P is probably released from the efferent fiber terminals. Slow negative synaptic potential, which corresponded to a slow depolarizing synaptic potential, was extracellularly induced in papillary afferent terminals for 45 s by stimulating the parasympathetic efferent fibers of GPN with high voltage pulses at 30 Hz for 10 s. This synaptic potential was also blocked by L-703,606. These data indicate that papillary afferent fiber endings are innervated by parasympathetic efferent fibers.

High extracellular Ca2+ stimulates Ca2+-activated Cl- currents in frog parathyroid cells through the mediation of arachidonic acid cascade.

Elevation of extracellular Ca(2+) concentration induces intracellular Ca(2+) signaling in parathyroid cells. The response is due to stimulation of the phospholipase C/Ca(2+) pathways, but the direct mechanism responsible for the rise of intracellular Ca(2+) concentration has remained elusive. Here, we describe the electrophysiological property associated with intracellular Ca(2+) signaling in frog parathyroid cells and show that Ca(2+)-activated Cl(-) channels are activated by intracellular Ca(2+) increase through an inositol 1,4,5-trisphophate (IP(3))-independent pathway. High extracellular Ca(2+) induced an outwardly-rectifying conductance in a dose-dependent manner (EC(50) ∼6 mM). The conductance was composed of an instantaneous time-independent component and a slowly activating time-dependent component and displayed a deactivating inward tail current. Extracellular Ca(2+)-induced and Ca(2+) dialysis-induced currents reversed at the equilibrium potential of Cl(-) and were inhibited by niflumic acid (a specific blocker of Ca(2+)-activated Cl(-) channel). Gramicidin-perforated whole-cell recording displayed the shift of the reversal potential in extracellular Ca(2+)-induced current, suggesting the change of intracellular Cl(-) concentration in a few minutes. Extracellular Ca(2+)-induced currents displayed a moderate dependency on guanosine triphosphate (GTP). All blockers for phospholipase C, diacylglycerol (DAG) lipase, monoacylglycerol (MAG) lipase and lipoxygenase inhibited extracellular Ca(2+)-induced current. IP(3) dialysis failed to induce conductance increase, but 2-arachidonoylglycerol (2-AG), arachidonic acid and 12S-hydroperoxy-5Z,8Z,10E,14Z-eicosatetraenoic acid (12(S)-HPETE) dialysis increased the conductance identical to extracellular Ca(2+)-induced conductance. These results indicate that high extracellular Ca(2+) raises intracellular Ca(2+) concentration through the DAG lipase/lipoxygenase pathway, resulting in the activation of Cl(-) conductance.

Response properties of nucleus reticularis lateralis neurons after electroacupuncture stimulation in rats.

A descending inhibitory mechanism from the periaqueductal gray (PAG) to the spinal cord through the nucleus raphe magnus (NRM) is strongly involved in endogenous analgesic system produced by acupuncture stimulation. In addition to the PAG to NRM system which descends in the medial pathway of the brain stem, the nucleus reticularis lateralis (NRL) situated in the lateral part of the brain stem is reported to play an important role in modulating centrifugal antinociceptive action. In the present study, to clarify the role of NRL in acupuncture analgesia, we investigated the response properties of NRL neurons to acupuncture stimulation. The majority of NRM-projecting NRL neurons were inhibited by electroacupuncture stimulation. This effect was antagonized by ionophoretic application of naloxone, indicating that endogenous opioids act directly onto these NRL neurons. By contrast, about half of spinal projecting NRL neurons were excited by electroacupuncture stimulation, suggesting that part of the NRL neurons may modulate pain transmission directly at the spinal level.

The receptor potential of frog taste cells in response to cold and warm stimuli.

Temperature sensitivity of frog taste cells was studied. The taste cell designated Type thermosensitive (TS) I cell was depolarized by warm stimulus at 30 degrees C and hyperpolarized by cold stimulus at 10 degrees C. The taste cell designated Type TS II cell was depolarized by the cold stimulus and hyperpolarized by the warm stimulus. Menthol solution at 20 degrees C, which selectively activates transient receptor potential (TRP) M8 channels sensitive to cold stimuli, depolarized Type TS II cells but not Types TS I cells. Thermal stimuli-induced receptor potentials were all blocked by a nonselective cation channel blocker flufenamic acid. The results indicate that Type TS I cells have warm sensor channels alone, Type TS II cells have cold sensor channels alone and both the channels are a nonselective cation channel. The candidate of cold sensor channel in Type TS II cells is a TRPM8 channel and that of warm sensor channel in Type TS I cells is likely to be a TRPM4-like channel from the published data. In a subset of taste cells, Types TS III and TS IV cells were found. The former was depolarized by both cold and warm stimuli, but the latter was hyperpolarized by both stimuli. Types TS III and TS IV cells might have both TRPM4-like and TRPM8 channels. It is supposed that depolarizations induced by both cold and warm stimuli were dominant in Type TS III cells and hyperpolarizations induced by both the thermal stimuli were dominant in Type TS IV cells.