Factors relating to the conditions and characteristics of mental health among the inhabitants in a methylmercury polluted area

OBJECTIVES: Little attention has been paid to mental health of inhabitants of methylmercury-polluted areas. The objective of this study was to examine the factors relating to the conditions and characteristics of mental health of inhabitants residing in a methylmercury-polluted area. METHODS: The eligible subjects of the study were inhabitants over the age of 40 years (n=301) living in two fishing village districts that were polluted by high concentrations of methylmercury. The study was conducted in two phases. In the first phase, a structured questionnaire was used to gather information on the current health condition and experience with Minamata disease of each subject through interviews. In the second phase, the General Health Questionnaire (GHQ)-30 was distributed to measure the psychological distress of the respondents. RESULTS: There were 133 (44.2%) study subjects. Factor analysis of the data collected using the GHQ was carried out and five factors that accounted for 57.9% of the total variance were selected. The first factor was labeled "depression and anxiety". Depression and anxiety were significantly associated with self-rated health status, the number of subjective symptoms, monthly outpatient visits and the receipt of compensation. Covariance structure analysis using the Amos 4.0 program demonstrated that depression and anxiety were significantly associated with the subjects' health condition, which in turn was influenced by experience with Minamata disease. CONCLUSION: Depression and anxiety of the inhabitants may be directly caused by the health condition. Further investigations with more precise and detailed measurements are needed to corroborate the causal relationship.     

Incidence and consequence of falls in inpatient rehabilitation of stroke patients

The incidence rate, location, and timing of falls and performance of activities of daily living (ADLs) in 256 patients with stroke admitted to an 88-bed rehabilitation ward was observed with information on falls and level of ADLs upon admission extracted from patients' records. Of 273 falls among 121 of the 256 patients, 229 occurred in the patient's room or lavatory and 147 within 4 weeks of admission. Significant differences were detected between motor subscores under 64 and over 65 on the Functional Independence Measure (FIM) in fall proportional analysis. The mean fall rate in motor subclass of 26 to 38 was higher than in other subgroups. Those with cognitive subscore on the FIM lower than 29 were prone to fall. Also, deteriorated motor and cognitive functions were associated with a high risk of falls.     

The attachment and entry of Leishmania (Leishmania) major into macrophages: observation by scanning electron microscope

Leishmaniasis, a zoonotic protozoan disease, starts with the inoculation of the Leishmania promastigotes into the skin at the time of blood ingestion by a female sandfly. The infection of leishmaniasis is established when the Leishmania organisms start their own intracellular multiplication after having been phagocytized by the host's macrophages. In the earliest stage of the infection, therefore, the attachment of the promastigates to the macrophages is essential. We incubated a mixed culture of macrophages (JM774-1A) and Leishmania (Leishmania) major for 6 hours in vitro and observed the process of the attachment between the parasite and host cell by scanning electron microscope. We found for the first time that the attachment between the two occurred at the site of the parasite body, in addition to the previously reported sites of the flagellar tip, flagellar base, and aflagellar tip (posterior pole).     

Time estimation during nocturnal sleep in human subjects

It has been postulated that time estimation during nocturnal sleep in humans can be explained by an interval timing clock inside the brain. However, no systematic investigations have been carried out with respect to how the human brain perceives the passage of time during sleep. The brain mechanisms of over- or underestimation of time spent in sleep have not yet been clarified. Here, we carried out an experimental study in which 11 healthy volunteers participated in time estimation trials scheduled six times during 9 h nocturnal sleep periods, under carefully controlled conditions. The time estimation ratio (TER: a ratio of subjective passage of time to actual time interval) decreased significantly from the first to the sixth trial. Individual TER was positively correlated with slow wave sleep prior to the trial, while it was negatively correlated with REM sleep. Our results indicate that the human brain has an ability to estimate the passage of time during nocturnal sleep without referring to time cues, and that the accuracy of this function fluctuates from overestimation in the early hours of sleep to underestimation in the last hours of sleep.     

Effect of intraocular lenses on preventing posterior capsule opacification: design versus material

PURPOSE: To compare the preventive effect of 4 types of design- and material-matched intraocular lenses (IOLs) on posterior capsule opacification (PCO). SETTING: Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. METHODS: After phacoemulsification, 1 of 2 matched IOLs in 3 groups was implanted in 1 eye and the other IOL in the contralateral eye of 4 to 6 rabbits. Three weeks postoperatively, posterior view and histopathological evaluations were performed and the capsular bending effect and amount of PCO evaluated. RESULTS: The capsular bending effect was similar between a sharp-edged acrylic IOL (Sensar 40e, AMO) and a sharp-edged silicone IOL (ClariFlex, AMO) and between the Sensar 40e IOL and a sharp-edged acrylic IOL (AcrySof, Alcon Laboratories). There was no significant difference between IOL types in the amount of PCO. The capsular bend effect was slightly better and the PCO amount slightly less with the ClariFlex IOL than with the round-edged silicone PhacoFlex II IOL (AMO). CONCLUSIONS: There was no substantial difference in PCO prevention between IOLs with sharp posterior optic edges, regardless of the IOL's material composition. The anterior edge design appeared to have no preventive effect. These results confirm that a sharp posterior optic edge is the main factor in preventing PCO.     

Music improves dopaminergic neurotransmission: demonstration based on the effect of music on blood pressure regulation

The mechanism by which music modifies brain function is not clear. Clinical findings indicate that music reduces blood pressure in various patients. We investigated the effect of music on blood pressure in spontaneously hypertensive rats (SHR). Previous studies indicated that calcium increases brain dopamine (DA) synthesis through a calmodulin (CaM)-dependent system. Increased DA levels reduce blood pressure in SHR. In this study, we examined the effects of music on this pathway. Systolic blood pressure in SHR was reduced by exposure to Mozart's music (K.205), and the effect vanished when this pathway was inhibited. Exposure to music also significantly increased serum calcium levels and neostriatal DA levels. These results suggest that music leads to increased calcium/CaM-dependent DA synthesis in the brain, thus causing a reduction in blood pressure. Music might regulate and/or affect various brain functions through dopaminergic neurotransmission, and might therefore be effective for rectification of symptoms in various diseases that involve DA dysfunction.     

Involvement of LOX-1 in dendritic cell-mediated antigen cross-presentation

Some exogenous antigens, such as heat shock proteins or apoptotic bodies, gain access to the MHC class I processing pathway and initiate CTL responses, a process called cross-priming. To be efficient in vivo, this process requires endocytosis of the antigen by dendritic cells via receptors which remain unidentified. Here, we report that scavenger receptors are the main HSP binding structures on human dendritic cells and identify LOX-1 as one of these molecules. A neutralizing anti-LOX-1 mAb inhibits Hsp70 binding to dendritic cells and Hsp70-induced antigen cross-presentation. In vivo, to target LOX-1 with a tumor antigen using an anti-LOX-1 mAb induces antitumor immunity. Thus, the scavenger receptor LOX-1 is certainly a promising target for cancer immunotherapy.     

Cholesteryl-hemisuccinate-induced apoptosis of promyelocytic leukemia HL-60 cells through a cyclosporin A-insensitive mechanism

We reported previously that alpha-tocopheryl-succinate (VES) induced apoptosis of cultured human promyelocytic leukemia cells (HL-60) (Free Radic Res 2000;33:407-18). We have now studied the effect of cholesteryl-hemisuccinate (CS) on the fate of HL-60 cells to clarify whether CS has an effect similar to that of VES. CS inhibited the growth of HL-60 cells without differentiation to granulocytes and induced DNA fragmentation and ladder formation. CS inhibited the phosphorylation of pleckstrin homology domain-containing protein kinase B (Akt) and initiated the activation of a caspase cascade. CS triggered the reaction leading to the cleavage of Bid and also released cytochrome c (Cyt. c) from mitochondria. In addition, CS induced mitochondrial membrane depolarization and translocation of Bax to mitochondria in HL-60 cells. However, CS did not induce an increase in the concentration of intracellular calcium ions in HL-60 cells. The membrane depolarization, Cyt. c release, and DNA fragmentation were inhibited by z-VAD-fluoromethylketone (z-VAD-fmk), a pan-caspase inhibitor, but not by cyclosporin A, an inhibitor of membrane permeability transition. These results suggested that CS-induced apoptosis of HL-60 cells might be caused by inhibiting Akt phosphorylation following cleavage of Bid through caspase-8 activation and subsequently via an Apaf complex-caspase cascade pathway.