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We examined the absorption of balenine (Bal) in mouse blood after the administration of a high-purity Bal prepared from opah muscle. Using HPLC with phenyl isothiocyanate pre-column derivatization, we successfully isolated imidazole peptides and their constituents. We detected Bal and 3-methylhistidine (3-Me-His) in mouse blood 1 h after the administration of opah-derived Bal. The concentrations of Bal and 3-Me-His significantly increased to 128.27 and 69.09 nmol/mL in plasma, respectively, but were undetectable in control and carnosine (Car)-administrated mice. In contrast, β-alanine and histidine did not increase in mouse plasma 1 h after the administration of Car and opah-derived Bal. The present study is the first report on the absorption of food-derived Bal in mouse blood and serves as a pilot study for future clinical trials.

There are increasing reports demonstrating high bioavailability of 4-hydroxyproline (4Hyp)-containing oligopeptides after oral ingestion of collagen hydrolysate and their bioactivity. In contrast, no study investigates the fate of another collagen-specific but minor amino acid, 3Hyp. Here, we identified Gly-3Hyp-4Hyp tripeptide in human blood at high concentrations, comparable to other 4Hyp-containing oligopeptides, after ingesting porcine skin collagen hydrolysate. Additionally, Gly-3Hyp-4Hyp uniquely maintained the maximum concentration until 4 h after the ingestion due to its exceptionally high resistance to peptidase/protease demonstrated by incubation with mouse plasma. In mice, oral administration of collagen hydrolysate prepared from bovine tendon, which contains a higher amount of 3Hyp, further increased blood Gly-3Hyp-4Hyp levels compared to that from bovine skin. Furthermore, Gly-3Hyp-4Hyp showed chemotactic activity on skin fibroblasts and promoted osteoblast differentiation. These results highlight the specific nature of the Gly-3Hyp-4Hyp tripeptide and its potential for health promotion and disease treatment.

Collagen peptides (CP) have been used as functional foods for enhancing skin and joint health. Further degradation of CP results in peptide sizes small enough to enter the bloodstream following absorption in the small intestine. We examined the effects of food matrices on CP degradation into short chain peptides and absorption efficiency after ingestion. Changes to hydroxyproline (Hyp)-containing peptide levels in CP after yogurt fermentation and in human plasma by co-ingestion of CP and yogurt, with or without fermentation, were evaluated by liquid chromatography-mass spectrometry (LC-MS). The fermentation of CP with yogurt resulted in the significant degradation of CP into several Hyp-containing peptides such as Ala-Hyp, Leu-Hyp, Phe-Hyp, Ala-Hyp-Gly, and Leu-Hyp-Gly. CP ingestion after yogurt fermentation significantly increased the plasma concentrations of Phe-Hyp, cyclo(Ala-Hyp), and cyclo(Pro-Hyp) compared to water-based CP ingestion. The co-ingestion of CP and yogurt without fermentation significantly increased the plasma levels of Ala-Hyp, Phe-Hyp, Ala-Hyp-Gly, Leu-Hyp-Gly, Pro-Hyp-Gly, cyclo(Ala-Hyp), cyclo(Glu-Hyp), and cyclo(Pro-Hyp). Overall, the co-ingestion of CP and yogurt with or without fermentation significantly enhanced the absorption of CP-derived peptides, represented by the high Cmax and area under the curve per 1 h (AUC, nmol/h&middot, mL) of Hyp-containing peptides. These results suggest that, in addition to increasing short chain Hyp-containing peptide levels via fermentation, yogurt matrices containing milk-derived peptides and/or lactic acid bacteria-derived peptidases may influence the efficient absorption of CP-derived peptides into human blood.

This study showed that gelatin ingestion significantly increased prolyl-hydroxyproline (Pro-Hyp) levels in plasma of 9 subjects, with maximum concentrations of 15.5 ± 3.0 nmol/mL 2 h post-ingestion. Hydroxyprolyl-glycine (Hyp-Gly) concentrations were significantly increased and reached a maximal level of 2.3 ± 0.5 nmol/mL 1 h post-ingestion of gelatin. A low molecular weight gelatin hydrolysate (LMW-GH) significantly enhanced concentrations of both peptides, while gelatin hydrolysate ingestion did not significantly enhance the maximum concentration and area under the plasma concentration–time curve (AUC) of Hyp-Gly relative to gelatin. The absorption of free Hyp following gelatin ingestion (94.4 ± 16.4 nmol/mL) was significantly lower relative to GH (150.9 ± 15.3 nmol/mL) and LMW-GH (169.1 ± 32.5 nmol/mL). The present study is the first report demonstrating that Hyp-containing peptides are elevated to μM levels in human plasma after gelatin ingestion. These results suggested that gelatin is useful as a functional food as effectively as GH.

Collagen-derived hydroxyproline (Hyp)-containing oligopeptides, known to have various physiological functions, are detected in blood at markedly higher concentrations after oral ingestion of collagen hydrolysate. Monitoring the absorption and metabolism of the bioactive peptides is essential to investigate the beneficial effects of collagen hydrolysate. We previously developed an internal standard mixture by sequential protease digestion of stable isotope-labeled collagen, which enabled highly accurate quantitation of collagen-derived oligopeptides by liquid chromatography-mass spectrometry (LC-MS). However, the use of proteases caused a profound imbalance in the generated peptides. Here, we employed partial acid hydrolysis to achieve more efficient and balanced peptide generation. Various stable isotope-labeled oligopeptides were detected after 0.5 h acid hydrolysis, and marked enhancement of peptide generation compared with the previous enzymatic method was observed, especially for Hyp-Gly (27.8 ± 0.6 ng/μg vs 0.231 ± 0.02 ng/μg). The acid hydrolysate was then heated to generate labeled cyclic dipeptides. Using the novel internal standard mixture in LC-MS, we were able to simultaneously quantitate 23 collagen-derived oligopeptides in human plasma and urine after oral administration of collagen hydrolysate.

A 66‐year‐old man was admitted with visual impairment, functional disability, and worsening glycemic control. On admission, he had optic atrophy without diabetic retinopathy in both eyes, sensory impairment of the lower extremities, ataxia, and cognitive impairment. As both serum and cerebrospinal fluid tested positive for syphilis, he was diagnosed with neurosyphilis and treated with antibiotics. Functional ability and cognitive function improved after conducting syphilis treatment; we consequently started him on an insulin self‐administration program. Two years later, his glycemic control has normalized. Dementia caused by neurosyphilis is one of the most important differential diagnoses of treatable dementia; hence, early diagnosis and early treatment are important.

Levels of short linear hydroxyproline (Hyp)-containing peptides, such as prolyl-hydroxyproline (Pro-Hyp), increase in human blood after the ingestion of collagen hydrolysate, which has been associated with beneficial effects for human skin and joints. The present study demonstrates the presence of a novel food-derived collagen peptide, cyclic Pro-Hyp, in human blood after the ingestion of collagen hydrolysate. The cyclic Pro-Hyp levels in plasma samples were estimated by liquid chromatography mass spectrometry (LC-MS). Cyclic Pro-Hyp levels significantly increased in the plasma after ingestion of collagen hydrolysate, reaching a maximum level after 2 h and then decreasing. The maximum level of cyclic Pro-Hyp in plasma ranged from 0.1413 to 0.3443 nmol/mL, representing approximately 5% of linear Pro-Hyp in plasma after ingestion of collagen hydrolysate. Addition of cyclic Pro-Hyp in medium at 7 nmol/mL significantly enhanced the growth rate of mouse skin fibroblasts on collagen gel more extensively compared to linear Pro-Hyp.

The highly successful Dirac equation predicts peculiar phenomena such as Klein tunnelling and Zitterbewegung (ZB) of electrons. From its conception by Erwin Schrödinger, ZB has been considered key in understanding relativistic quantum mechanics. However, observing the ZB of electrons has proved difficult, and instead various emulations of the phenomenon have been proposed producing several successes. Concerning charge transport in semiconductors and graphene, expectations were high but little has been reported. Here, we report a surprisingly large ZB effect on charge transport in a semiconductor nanostructure playing “flat pinball”. The setup is a narrow strip of InAs two-dimensional electron gas with strong Rashba spin–orbit coupling. Six quantum point contacts act as pinball pockets. In transiting between two contacts, ZB appears as a large reproducible conductance fluctuation that depends on the in-plane magnetic field. Numerical simulations successfully reproduced our experimental observations confirming that ZB causes this conductance fluctuation.

We observed supercurrent through an n-type ferromagnetic semiconductor (In,Fe)As. For the purpose we prepared S/F/S (S: superconductor, F: ferromagnet) junctions, which exhibited zero resistance up to 1 µm of junction width with critical current over 1 µA below 1 K. The long reach of the superconducting proximity effect suggests that the induced superconductivity is brought about by spin-triplet paring in (In,Fe)As.

Involuntary movement can be classified into tremor, chorea, athetosis/dystonia, ballismus, myoclonus, or tic. In clinical settings, diagnosing a cause of involuntary movement is generally performed by observation and interview. Proper diagnosis relies on the doctor's experience and knowledge. Objective assessment tool to support doctors for discriminating involuntary movements are requested. An accelerometer is a portable and noninvasive device. We propose to use acceleration of body sites as an evidence of the discrimination. In this study, we analyse the characteristics of left upper limb's movement at rest and postural task of participants with/without neurological motor impairment. The results suggest that waveform, the number of base-line crossing and the root mean square value of acceleration have the potential to assess the involuntary movement.

Children with cerebral palsy often use adaptive seating systems to access and operate assistive technology devices, such as speech generation and environment control devices, to communicate with surrounding persons and interact with electric appliances. Proper seating provided by occupational and physical therapists is crucial to inhibit abnormal movements, reflexes and tone, thereby can maximise the children's ability to function. More frequent seating assessments in daily living are necessary to maintain the seating. The goal of this study is to develop a quantitative method to assess the quality of movement while undertaking touch operations by using a set of portable accelerometers. We conducted an in-depth case study on a girl with cerebral palsy and evaluate agreements between the root mean square values of acceleration and the occupational therapist's subjective assessment. Our assessment and the OT's subjective assessment reached 69.3% agreement and the RMS values could detect the very little involuntary movement. The results suggest that the RMS values have the potential to be the quantitative evidence for seating.