Mucosal-associated invariant T cells are activated in an interleukin-18-dependent manner in Epstein-Barr virus-associated T/natural killer cell lymphoproliferative diseases.

Mucosal-associated invariant T (MAIT) cells are a type of innate immune cells that protect against some infections. However, the involvement of MAIT cells in Epstein-Barr virus-associated T/natural killer cell lymphoproliferative diseases (EBV-T/NK-LPD) is unclear. In this study, we found that MAIT cells were highly activated in the blood of patients with EBV-T/NK-LPD. MAIT cell activation levels correlated with disease severity and plasma IL-18 levels. Stimulation of healthy peripheral blood mononuclear cells with EBV resulted in activation of MAIT cells, and this activation level was enhanced by exogenous IL-18. MAIT cells stimulated by IL-18 might thus be involved in the immunopathogenesis of EBV-T/NK-LPD.

Allometric scaling of skin weight and thickness to body weight in relation to taxonomic orders and habitats in mammals.

Skin is the largest organ in a mammal body, and it exhibits most significant range of adaptations to different habitats. It is a complex, biological composite structure, consisting of epidermis, dermis and subcutaneous tissues and is used for the therapeutic application of medical devices to improve healthcare. Extensive studies have been performed on the roles of the skin; however, little is known on its physiological characteristics in relation to body size among different species. The purpose of this study was therefore to evaluate the allometric scaling of skin weight (SW) and thickness (ST) to body weight (BW) in relation to genetics and habitats. Also analysed the relationship of BW to thicknesses of epidermis, dermis and subcutaneous tissues. This study used 249 adult animals of both sexes, belonging to 144 species, clustered in 18 taxonomic orders and five types of habitats. The animals were obtained from various sources in Japan. SW and BW were weighed, and ST was measured using a calliper followed by data analysis. Results showed that SW and ST were related to BW [log SW = 0.969 × logBW - 0636, adjust. R2 : 0.975]. The BW increased with increasing skin dermal thickness (y = 0.3916x + 1.5253, adjust. R2 : 0.6921), slightly with epidermal thickness (y = 0.2495x + 0.3984, adjust. R2 : 0.3402), but not all with the thickness of subcutaneous tissues (y = 0.1454x + 2.2437, adjust. R2 : 0.0752). The ratio of SW to BW (SW/BW) distributed over a large range from 0.06 to 0.64 values and varied among animal taxonomic orders and their dwelling habitats. Close relationship of BW to SW/BW was observed in species weighing ≥200 g but not in species weighing <200 g. In conclusion, SW and ST in mammals are determined by BW. The SW/BW varies based on BW, taxonomic orders and habitat and is large in small mammals weighing ≥200 g to provide a mechanism used for survival strategy.

Differential expression of myosin heavy chain isoforms type II in skeletal muscles of polar and black bears.

In this study, the pattern of myosin heavy chain (MHC) isoforms expression in skeletal muscles of the trunk, forelimb and hindlimb in Polar Bear (PB) Ursus maritimus; American Black Bear (AmBB), Ursus americanus and Asian Black Bear (AsBB), Ursus thibetanus was analysed by immunohistochemistry and SDS-PAGE. Results showed that slow (MHC-I) and fast (MHC-II) isoforms exist in muscles of bears. Type II fibres were classified further into Type IIa and IIx in PB but not in AsBB and AmBB. The distribution of Type I and Type II fibres in the trunk, forelimb and hindlimb varied based on muscle type and animal species. The proportions of Type I fibres formed approximately one-third of muscle composition in PB (trunk, 32.0%; forelimb, 34.7%; hindlimb, 34.5%) and a half in both AsBB and AmBB whereas Type IIa and IIx formed approximately two-third in PB (trunk, 68.0%; forelimb, 65.3%; hindlimb, 65.5%) and a half of Type II in both AmBB and AsBB. PB is a good swimmer, lives in Arctic Ocean on slippery ice catching aquatic mammals such as seals and is larger in size compared to the medium sized AmBB (living in forest) and AsBB (arboreal). The results suggest that in bears, there is greater diversity in MHC isoforms II, being expressed in selected fast contracting skeletal muscles in response to variety of environments, weight bearing and locomotion.

Yersinia pseudotuberculosis Infection Accompanied by Intussusception and Incomplete Kawasaki Disease in a 7-year-old Girl.

Infection with Yersinia pseudotuberculosis, a known causal pathogen of human bacterial gastroenteritis, causes various symptoms and complications. A previously healthy 7-year-old girl was admitted because of fever and gastrointestinal symptoms. She was initially diagnosed with intussusception by abdominal ultrasonography. Although the patient was successfully treated by air enema, the fever persisted. The patient was then diagnosed with incomplete Kawasaki disease based on the presence of four principal clinical features. Intravenous immunoglobulin and oral aspirin were initiated. The patient defervesced and the other symptoms subsided after the treatment. Cardiac ultrasound results showed normal coronary arteries. Because of the gastrointestinal symptoms, stool samples were cultured repeatedly, only to yield normal flora. However, serum levels of anti-Y. pseudotuberculosis-derived mitogen antibody were elevated between the 7th and 18th days of the disease, thereby confirming Y. pseudotuberculosis infection. Because Y. pseudotuberculosis infection results in various clinical manifestations, we must be aware of each symptom and address them systematically.

Three Characteristics of Cheetah Galloping Improve Running Performance Through Spinal Movement: A Modeling Study.

Cheetahs are the fastest land animal. Their galloping shows three characteristics: small vertical movement of their center of mass, small whole-body pitching movement, and large spine bending movement. We hypothesize that these characteristics lead to enhanced gait performance in cheetahs, including higher gait speed. In this study, we used a simple model with a spine joint and torsional spring, which emulate the body flexibility, to verify our hypothesis from a dynamic perspective. Specifically, we numerically searched periodic solutions and evaluated what extent each solution shows the three characteristics. We then evaluated the gait performance and found that the solutions with the characteristics achieve high performances. This result supports our hypothesis. Furthermore, we revealed the mechanism for the high performances through the dynamics of the spine movement. These findings extend the current understanding of the dynamic mechanisms underlying high-speed locomotion in cheetahs.

Center of Mass Offset Enhances the Selection of Transverse Gallop in High-Speed Running by Horses: A Modeling Study.

Horses use the transverse gallop in high-speed running. However, different animals use different gaits, and the gait preference of horses remains largely unclear. Horses have fore-aft asymmetry in their body structure and their center of mass (CoM) is anteriorly located far from the center of the body. Since such a CoM offset affects the running dynamics, we hypothesize that the CoM offset of horses is important in gait selection. In order to verify our hypothesis and clarify the gait selection mechanisms by horses from a dynamic viewpoint, we developed a simple model with CoM offset and investigated its effects on running. Specifically, we numerically obtained periodic solutions and classified these solutions into six types of gaits, including the transverse gallop, based on the footfall pattern. Our results show that the transverse gallop is optimal when the CoM offset is located at the position estimated in horses. Our findings provide useful insight into the gait selection mechanisms in high-speed running of horses.

The Plasma Level of Interleukin-1ß Can Be a Biomarker of Angiopathy in Systemic Chronic Active Epstein-Barr Virus Infection.

Systemic chronic active Epstein-Barr virus infection (sCAEBV) is an EBV-positive T- or NK-cell neoplasm revealing persistent systemic inflammation. Twenty-five percent of sCAEBV patients accompany angiopathy. It is crucial to clarify the mechanisms of angiopathy development in sCAEBV because angiopathy is one of the main causes of death. Interleukin-1ß (IL-1ß) is reported to be involved in angiopathy onset. We investigated if IL-1ß plays a role as the inducer of angiopathy of sCAEBV. We detected elevated IL-1ß levels in four out of 17 sCAEBV patient's plasma. Interestingly, three out of the four had clinically associated angiopathy. None of the other patients with undetectable level of IL-1ß had angiopathy. In all patients with high plasma levels of IL-1ß and vascular lesions, EBV-infected cells were CD4-positive T cells. In one patient with high plasma IL-1ß, the level of IL-1ß mRNA of the monocytes was 17.2 times higher than the level of the same patient's EBV-infected cells in peripheral blood. In Ea.hy926 cells, which are the models of vascular endothelial cells, IL-1ß inhibited the proliferation and induced the surface coagulation activity. IL-1ß is a potent biomarker and a potent therapeutic target to treat sCAEBV accompanying angiopathy.

Underground locomotion in moles: kinematic and electromyographic studies of locomotion in the Japanese mole (Mogera wogura).

A series of kinematic and electromyographic (EMG) studies were conducted to characterize the neural control of underground movement in the Japanese mole, Mogera wogura. For the purposes of the present study, the locomotion of moles was classified into two modes: crawling, which comprises alternate movements of the left and right forelimbs; and burrowing, in which both forelimbs move synchronously. In crawling, moles exhibit both symmetrical and asymmetrical locomotion independent of cycle duration and speed of travel. In burrowing, the movements of fore- and hindlimbs, and of the left and right hindlimb are loosely coordinated. We divided cycles of limb movement into recovery stroke phase and power stroke phases and observed that control of cycle duration in forelimbs and hindlimbs was achieved through changes to both recovery and power stroke phases. Our results showed phasic EMG bursts in various muscles in moles, whose timing differed from that seen in terrestrial four-legged mammals such as cats and dogs. The difference was especially apparent in the m. longissimus, in which EMG bursts recorded at the level of the thoracic and lumbar vertebrae corresponded to movements of the forelimbs and hindlimbs, respectively. Thus, we conclude that moles have evolved a distinctive mechanism of neural control to perform their specialized forms of underground locomotion.

Muscle fibre distribution in forelimb, hindlimb and trunk muscles in three bat species: The little Japanese horseshoe, greater horseshoe and Egyptian fruit.

This study characterised muscle fibres in trunk, forelimb and hindlimb muscles of three bat species: little Japanese horseshoe (Rhinolophus cornutus), greater horseshoe (Rhinolophus ferrumequinum) and Egyptian fruit (Rousettus aegyptiacus). Twenty-seven muscles from trunk, forelimb and hindlimb were dissected, weighed and analysed by immunohistochemistry and sodium didecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and determined their cross-sectional areas (CSA). Results showed that Type IIa and Type IIa/x made the highest proportion of total muscle mass. Moderate proportion was formed by Type IIb. Type I and IIx appeared at very low levels in all bats. Type IIb was the only fibre type detected in patagial muscles in wing membrane of greater horseshoe while other fibre types were not observed. Type I muscle fibres were very few and appeared infrequently in fifteen muscles of Egyptian fruit and in only one muscle in each, greater horseshoe and little Japanese horseshoe. Type IIx was also detected in three muscles in greater horseshoe and only one muscle in Egyptian fruit but none in little Japanese horseshoe. The highest average CSA µm2 was detected in Type IIb and values were 734.2µm2 for LHB; 1537.9µm2 for GHB and 1,720.9µm2 for EFB. Lowest and undetermined values were observed for Type I and IIx. These data demonstrate that Type IIa, IIa/x and IIb form significant proportion of adult bat muscle mass and Type IIb is the largest fibre type. The distribution pattern is suggestive of specialised functions of the fibres in relation to orientation and speed of bats during flight.

Dynamical determinants enabling two different types of flight in cheetah gallop to enhance speed through spine movement.

Cheetahs use a galloping gait in their fastest speed range. It has been reported that cheetahs achieve high-speed galloping by performing two types of flight through spine movement (gathered and extended). However, the dynamic factors that enable cheetahs to incorporate two types of flight while galloping remain unclear. To elucidate this issue from a dynamical viewpoint, we developed a simple analytical model. We derived possible periodic solutions with two different flight types (like cheetah galloping), and others with only one flight type (unlike cheetah galloping). The periodic solutions provided two criteria to determine the flight type, related to the position and magnitude of ground reaction forces entering the body. The periodic solutions and criteria were verified using measured cheetah data, and provided a dynamical mechanism by which galloping with two flight types enhances speed. These findings extend current understanding of the dynamical mechanisms underlying high-speed locomotion in cheetahs.