Exploring the use of fish as indicators of eicosapentaenoic and docosahexaenoic supply in lake ecosystems.

An adequate supply of food sources with high levels (i.e., weight proportion of total fatty acids) and contents (i.e., absolute amount per mass) of long chain polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are important for ecosystems. Therefore, the supply of EPA and DHA from basal food sources is a useful indicator of ecosystem health. To determine whether EPA and DHA levels and contents in fish can be used as indicators of EPA and DHA supply in lakes, five dominant species of fish and basal food sources (seston and sediment) were collected monthly from June to November from 2016 to 2021 from Lake Hachiro, Japan. Seston and Hypomesus nipponensis were collected from 12 lakes (one collection per lake) with varying seston contents in EPA and DHA. The trends of EPA and DHA in all fish species were similar to those of the basal food sources. Correlation analysis showed that the EPA levels were strongly correlated between fish and seston; moreover, the correlation coefficient increased when a 1- or 2-month moving average was applied to the basal food sources, suggesting that fish represent a time-integrated supply of EPA and DHA. EPA levels of H. nipponensis had the highest correlation coefficients with seston among all fish species. EPA levels of H. nipponensis were significantly correlated with those of seston among lakes. The results of this study suggest that H. nipponensis is a useful indicator of EPA and DHA supplies in lake ecosystems.

Identifying a breeding habitat of a critically endangered fish, Acheilognathus typus, in a natural river in Japan.

Freshwater biodiversity has been severely threatened in recent years, and to conserve endangered species, their distribution and breeding habitats need to be clarified. However, identifying breeding sites in a large area is generally difficult. Here, by combining the emerging environmental DNA (eDNA) analysis with subsequent traditional collection surveys, we successfully identified a breeding habitat for the critically endangered freshwater fish Acheilognathus typus in the mainstream of Omono River in Akita Prefecture, Japan, which is one of the original habitats of this species. Based on DNA cytochrome B sequences of A. typus and closely related species, we developed species-specific primers and a probe that were used in real-time PCR for detecting A. typus eDNA. After verifying the specificity and applicability of the primers and probe on water samples from known artificial habitats, eDNA analysis was applied to water samples collected at 99 sites along Omono River. Two of the samples were positive for A. typus eDNA, and thus, small fixed nets and bottle traps were set out to capture adult fish and verify egg deposition in bivalves (the preferred breeding substrate for A. typus) in the corresponding regions. Mature female and male individuals and bivalves containing laid eggs were collected at one of the eDNA-positive sites. This was the first record of adult A. typus in Omono River in 11 years. This study highlights the value of eDNA analysis to guide conventional monitoring surveys and shows that combining both methods can provide important information on breeding sites that is essential for species' conservation.

Effect of Probiotic Bifidobacterium breve in Improving Cognitive Function and Preventing Brain Atrophy in Older Patients with Suspected Mild Cognitive Impairment: Results of a 24-Week Randomized, Double-Blind, Placebo-Controlled Trial.

BACKGROUND: Probiotics have been reported to ameliorate cognitive impairment. OBJECTIVE: We investigated the effect of the probiotic strain Bifidobacterium breve MCC1274 (A1) in enhancing cognition and preventing brain atrophy of older patients with mild cognitive impairment (MCI). METHODS: In this RCT, 130 patients aged from 65 to 88 years old with suspected MCI received once daily either probiotic (B. breve MCC1274, 2×1010 CFU) or placebo for 24 weeks. Cognitive functions were assessed by ADAS-Jcog and MMSE tests. Participants underwent MRI to determine brain atrophy changes using Voxel-based Specific Regional Analysis System for Alzheimer's disease (VSRAD). Fecal samples were collected for the analysis of gut microbiota composition. RESULTS: Analysis was performed on 115 participants as the full analysis set (probiotic 55, placebo 60). ADAS-Jcog subscale "orientation" was significantly improved compared to placebo at 24 weeks. MMSE subscales "orientation in time" and "writing" were significantly improved compared to placebo in the lower baseline MMSE (< 25) subgroup at 24 weeks. VSRAD scores worsened in the placebo group; probiotic supplementation tended to suppress the progression, in particular among those subjects with progressed brain atrophy (VOI Z-score ≥1.0). There were no marked changes in the overall composition of the gut microbiota by the probiotic supplementation. CONCLUSION: Improvement of cognitive function was observed on some subscales scores only likely due to the lower sensitiveness of these tests for MCI subjects. Probiotics consumption for 24 weeks suppressed brain atrophy progression, suggesting that B. breve MCC1274 helps prevent cognitive impairment of MCI subjects.

Clinical effects of high oral dose of donepezil for patients with Alzheimer's disease in Japan.

BACKGROUND: Donepezil 10 mg/day gained approval in Japan in August 2007 for the treatment of cognitive dysfunction in advanced Alzheimer's disease. METHODS: We evaluated the efficacy and adverse effects of donepezil when the dose was increased to 10 mg/day in 61 Japanese patients with Alzheimer's disease. Cognitive function was evaluated using the Revised Hasegawa Dementia Scale and mini-mental state examination at the day before starting, and at 4, 8 and 24 weeks after starting donepezil 10 mg/day. The relationship with apolipoprotein E4 was also investigated. RESULTS: The Revised Hasegawa Dementia Scale and mini-mental state examination scores were not statistically significantly different at any time after starting donepezil 10 mg/day. It can be anticipated that donepezil 10 mg/day will especially inhibit deterioration of cognitive function in advanced Alzheimer's disease. The incidence of adverse events was 11.5%, lower than the rate of 40% or higher recorded during previous clinical trials. CONCLUSIONS: The progression of cognitive dysfunction could be inhibited by increasing the dose of donepezil to 10 mg/day. It was suggested that longer-term treatment with 5 mg/day might lead to fewer adverse events when the dose is increased to 10 mg/day.

Brown hagfish from the northwest and east coasts of Honshu, Japan are genetically different.

The brown hagfish (Eptatretus atami) is one of several known hagfish species occurring in Japanese coastal waters. To date, there has been no research studying genetic polymorphisms in the species. In the present study, we analyzed differences in nucleotide sequences between two populations: one from Suruga Bay on the Pacific coast of Honshu, Japan, and the other from the Sea of Japan, off Akita on the northwest coast of Honshu. We sequenced part of the cytochrome oxidase subunit 1 gene (COX1) from the mitochondrial genome, and three G protein-coupled receptor genes from the nuclear genome. Phylogenetic networks of all four genes showed divergence between the two populations. Further, comparison of the COX1 data using a phylogenetic tree for a range of hagfish species indicated clear differences between the populations, suggesting that they differ at the species level. The numbers of their teeth, in particular of fused cusps (anterior/posterior multicusps), also supported these findings. Individuals of the Suruga Bay population had 3/3 fused cusps, as described for E. atami, whereas individuals of the Akita population had 3/2 fused cusps. These results suggest that the brown hagfish from the Sea of Japan, off the northwest coast of Honshu, is a distinct species from E. atami.

Impaired heart rate variability in patients with dementia with Lewy bodies: Efficacy of electrocardiogram as a supporting diagnostic marker.

OBJECTIVE: It has been suggested that impaired heart rate variability (HRV) may be an early sign of Parkinson's disease (PD). The aim of this study was to determine whether HRV can be employed in order to differentiate between dementia with Lewy bodies (DLB) and Alzheimer's disease (AD). METHODS: We examined HRV in 30 probable DLB patients (16 men and 14 women; mean age, 79.9 years; SD, 4.7 years), and 30 probable AD patients (15 men and 15 women; mean age, 79.8 years; SD, 5.6 years), compared with that in 20 age- and sex-matched controls. Subjects with other causes of impaired HRV were excluded. HRV was determined using the RR intervals of a 5-min electrocardiogram recording. Measurements of beat-to-beat RR variability, including time domains [(RR-standard deviation (SDNN), percentage of consecutive RR intervals differing by more than 50 msec (pNN50), and root mean square difference of successive RR intervals (RMSSD)), and frequency domains [very low- (VLF), low- (LF), and high-frequency (HF) components, and total spectral power (Total power)], were assessed retrospectively. The association between these HRV parameters and cardiac iodine-123 metaiodobenzylguanidine ((123)I-MIBG) scintigraphy were investigated in 22 probable DLB patients. RESULTS: DLB group showed significant decreases compared to AD group in almost all HRV parameters including SDNN, pNN50, RMSSD, VLF, LF, HF, and Total power. Among these, SDNN, VLF, and Total power were correlated with the (123)I-MIBG delayed heart to mediastinum ratio. CONCLUSION: Impaired HRV was detected in patients with probable DLB. Non-invasive and routine electrocardiogram may have potential in differentiating DLB from AD.