174 research outputs found
Stereolithographic biomodeling of equine ovary based on 3D serial digitizing device
The 3D internal structure microscopy (3D-ISM) was applied to the equine ovary, which possesses peculiar structural characteristics. Stereolithography was applied to make a life-sized model by means of data obtained from 3D-ISM. Images from serially sliced surfaces contributed to a successful 3D reconstruction of the equine ovary. Photopolymerized resin models of equine ovaries produced by stereolithography can clearly show the internal structure and spatial localizations in the ovary. The understanding of the spatial relationship between the ovulation fossa and follicles and/or corpora lutea in the equine ovary was a great benefit. The peculiar structure of the equine ovary could be thoroughly observed and understood through this model
Notable underlying mechanism for pancreatic β-cell dysfunction and atherosclerosis: Pleiotropic roles of incretin and insulin signaling
Under healthy conditions, pancreatic β-cells produce and secrete the insulin hormone in response to blood glucose levels. Under diabetic conditions, however, β-cells are compelled to continuously secrete larger amounts of insulin to reduce blood glucose levels, and thereby, the β-cell function is debilitated in the long run. In the diabetic state, expression levels of insulin gene transcription factors and incretin receptors are downregulated, which we think is closely associated with β-cell failure. These data also suggest that it would be better to use incretin-based drugs at an early stage of diabetes when incretin receptor expression is preserved. Indeed, it was shown that incretin-based drugs exerted more protective effects on β-cells at an early stage. Furthermore, it was shown recently that endothelial cell dysfunction was also associated with pancreatic β-cell dysfunction. After ablation of insulin signaling in endothelial cells, the β-cell function and mass were substantially reduced, which was also accompanied by reduced expression of insulin gene transcription factors and incretin receptors in β-cells. On the other hand, it has been drawing much attention that incretin plays a protective role against the development of atherosclerosis. Many basic and clinical data have underscored the importance of incretin in arteries. Furthermore, it was shown recently that incretin receptor expression was downregulated in arteries under diabetic conditions, which likely diminishes the protective effects of incretin against atherosclerosis. Furthermore, a series of large-scale clinical trials (SPAED-A, SPIKE, LEADER, SUSTAIN-6, REWIND, PIONEER trials) have shown that various incretin-related drugs have beneficial effects against atherosclerosis and subsequent cardiovascular events. These data strengthen the hypothesis that incretin plays an important role in the arteries of humans, as well as rodents.Kaneto, H.; Obata, A.; Kimura, T.; Shimoda, M.; Sanada, J.; Fushimi, Y.; Katakami, N.; Matsuoka, T.; Kaku, K. Notable Underlying Mechanism for Pancreatic β-Cell Dysfunction and Atherosclerosis: Pleiotropic Roles of Incretin and Insulin Signaling. Int. J. Mol. Sci. 2020, 21, 9444
Effects of alprazolam on capture stress-related serum cortisol responses in Korean raccoon dogs (Nyctereutes procyonoides koreensis)
The purpose of this study was to evaluate the effect of alprazolam on the stress that Korean raccoon dogs (Nyctereutes procyonoides koreensis) may experience while caught in a live trap by measuring their serum cortisol response. The animals were placed in a live trap with or without being pretreated with oral doses of alprazolam. In both groups, pre-trap blood samples were initially collected without anesthesia before the animals were positioned in the live trap; then post-trap blood samples were collected after the animals had remained in the live trap for 2 h. Changes in cortisol levels were observed using a chemiluminescent immunoassay. The level of cortisol increased in the control group and decreased in the alprazolam-pretreatment group (p < 0.05). In this study, we demonstrated that alprazolam pretreatment reduced stress during live trap capture
Absence of the guttural pouch in a newborn Indian rhinoceros demonstrated by three-dimensional image observations
Abstract. CT scanning and its related three-dimensional image techniques were applied for a carcass head of a newborn Indian rhinoceros (Rhinoceros unicornis) to clarify if the guttural pouch is well-developed or not in the early growth stages of this species. Observations from the sections of the CT three-dimensional reconstructed image reveal that the guttural pouch is not present around the stylohyoid bone in a new born Indian rhinoceros. Since the absence of the guttural pouch has been confirmed also in adult rhinoceros, we can point out that the guttural pouch does not disappear during the growth stages, but is originally absent in the newborn. Although the well-developed guttural pouch in the horse and ass has attracted anatomists, we can conclude that the guttural pouch is not commonly observed in the perissodactyls, but in a few species of Equus, and that the guttural pouch is adapted only to restricted roles in the smaller taxa within perissodactyls. Key words: CT, growth, guttural pouch, perissodactyls, Rhinoceros unicornis. The accessory apparatus of the respiratory system such as guttural pouch (auditory tube diverticulum) has remained morphologically unclear in large-sized mammals. The perissodactyls have attracted comparative anatomists since the well-developed guttural pouch was observed in the domesticated horse (Bourdelle and Bresso
Novel erythrocyte pits in small tropical ruminant, lesser mouse deer.
We examined unique erythrocyte pits of the peripheral blood and bone marrow in the lesser mouse deer, Tragulus javanicus, using scanning electron microscope (SEM) and transmission electron microscope (TEM). Under the SEM observation, the pit was observed as a hole on both mature erythrocytes of the peripheral blood and immature erythrocytes of the bone marrow. By the TEM, the mature erythrocytes had a vacuole, which showed complicated shape and occupied considerable space within the cytoplasm. The vacuole was communicated extracellularly by perforation, which corresponded to the hole on the cell surface. In the bone marrow, erythroblast and reticulocytes have a cytoplasmic vacuole. This abnormal feature of the erythrocytes is peculiar to the mouse deer, and not found in other tropical ruminants. Despite the disadvantage of volume loss from the small erythrocytes, the mouse deer were healthy and showed no signs of anaemia
Atrial Fibrillation Detection and Ischemic Stroke Recurrence in Cryptogenic Stroke: A Retrospective, Multicenter, Observational Study
Todo K., Okazaki S., Doijiri R., et al. Atrial Fibrillation Detection and Ischemic Stroke Recurrence in Cryptogenic Stroke: A Retrospective, Multicenter, Observational Study. Journal of the American Heart Association 13, e031508 (2024); https://doi.org/10.1161/JAHA.123.031508.BACKGROUND: Atrial fibrillation (AF) is known to be a strong risk factor for stroke. However, the risk of stroke recurrence in patients with cryptogenic stroke with AF detected after stroke by an insertable cardiac monitor (ICM) is not well known. We sought to evaluate the risk of ischemic stroke recurrence in patients with cryptogenic stroke with and without ICM-detected AF. METHODS AND RESULTS: We retrospectively reviewed patients with cryptogenic stroke who underwent ICM implantation at 8 stroke centers in Japan. Cox regression models were developed using landmark analysis and time-dependent analysis. We set the target sample size at 300 patients based on our estimate of the annualized incidence of ischemic stroke recurrence to be 3% in patients without AF detection and 9% in patients with AF detection. Of the 370 patients, 121 were found to have AF, and 110 received anticoagulation therapy after AF detection. The incidence of ischemic stroke recurrence was 4.0% in 249 patients without AF detection and 5.8% in 121 patients with AF detection (P=0.45). In a landmark analysis, the risk of ischemic stroke recurrence was not higher in patients with AF detected ≤90 days than in those without (hazard ratio, 1.47 [95% CI, 0.41–5.28]). In a time-dependent analysis, the risk of ischemic stroke recurrence did not increase after AF detection (hazard ratio, 1.77 [95% CI, 0.70–4.47]). CONCLUSIONS: The risk of ischemic stroke recurrence in patients with cryptogenic stroke with ICM-detected AF, 90% of whom were subsequently anticoagulated, was not higher than in those without ICM-detected AF
Subspecific Status of the Korean Tiger Inferred by Ancient DNA Analysis
The tiger population that once inhabited the Korean peninsula was initially considered a unique subspecies (Panthera tigris coreensis), distinct from the Amur tiger of the Russian Far East (P. t. altaica). However, in the following decades, the population of P. t. coreensis was classified as P. t. altaica and hence forth the two populations have been considered the same subspecies. From an ecological point of view, the classification of the Korean tiger population as P. t. altaica is a plausible conclusion. Historically, there were no major dispersal barriers between the Korean peninsula and the habitat of Amur tigers in Far Eastern Russia and northeastern China that might prevent gene flow, especially for a large carnivore with long-distance dispersal abilities. However, there has yet to be a genetic study to confirm the subspecific status of the Korean tiger. Bone samples from four tigers originally caught in the Korean peninsula were collected from two museums in Japan and the United States. Eight mitochondrial gene fragments were sequenced and compared to previously published tiger subspecies\u27 mtDNA sequences to assess the phylogenetic relationship of the Korean tiger. Three individuals shared an identical haplotype with the Amur tigers. One specimen grouped with Malayan tigers, perhaps due to misidentification or mislabeling of the sample. Our results support the conclusion that the Korean tiger should be classified as P. t. altaica, which has important implications for the conservation and reintroduction of Korean tigers
Optical study of charge instability in CeRu2Al10 in comparison with CeOs2Al10 and CeFe2Al10
The anisotropic electronic structure responsible for the antiferromagnetic transition in CeRu2Al10 at the unusually high temperature of T0=28 K was studied using optical conductivity spectra, Ce 3d x-ray photoemission spectra, and band calculation. It was found that the electronic structure in the ac plane is that of a Kondo semiconductor, whereas that along the b axis has a nesting below 32 K (slightly higher than T0). These characteristics are the same as those of CeOs2Al10 [ S. Kimura et al. Phys. Rev. Lett. 106 056404 (2011)]. The c-f hybridization intensities between the conduction and 4f electrons of CeRu2Al10 and CeOs2Al10 are weaker than that of CeFe2Al10, showing no magnetic ordering. These results suggest that the electronic structure with one-dimensional weak c-f hybridization along the b axis combined with two-dimensional strong hybridization in the ac plane causes charge-density wave (CDW) instability, and the CDW state then induces magnetic ordering
Distribution of lectin-bindings in the testis of the lesser mouse deer, Tragulus javanicus
The distribution of lectin bindings in the testis of the smallest ruminant, lesser mouse deer (Tragulus javanicus), was studied using 12 biotinylated lectins specific for d-galactose (peanut agglutinin PNA, Ricinus communis agglutinin RCA I), N-acetyl-d-galactosamine (Dolichos biflorus agglutinin DBA, Vicia villosa agglutinin VVA, Soybean agglutinin SBA), N-acetyl-d-glucosamine and sialic acid (wheat germ agglutinin WGA, s-WGA), d-mannose and d-glucose (Lens culinaris agglutinin LCA, Pisum sativum agglutinin PSA, Concanavalin A Con A), l-fucose (Ulex europaeus agglutinin UEA I), and oligosaccharide (Phaseolus vulgaris agglutinin PHA-E) sugar residues. In Golgi-, cap-, and acrosome-phase spermatids, lectin-bindings were found in the acrosome (PNA, RCA I, VVA, SBA, WGA and s-WGA), and in the cytoplasm (PNA, RCA I, VVA, SBA, WGA, LCA, PSA, Con A and PHA-E). s-WGA binding was confined to the spermatid acrosome, but other lectins were also observed in spermatocytes. In spermatogonia, VVA, WGA, Con A, and PHA-E bindings were observed. Sertoli cells were intensely stained with DBA and Con A, and weakly with PHA-E. In interstitial Leydig cells, RCA I, DBA, VVA, Con A, PSA, LCA, WGA and PHA-E were positive. UEA I was negative in all cell types including spermatogenic cells. Unusual distribution of lectin-bindings noted in the testis of lesser mouse deer included the limited distribution of s-WGA only in the spermatid acrosome, the distribution of DBA in Sertoli cells, Leydig cells and lamina propria, and the absence of UEA I in all type cells. The present results were discussed in comparison with those of other animals and their possible functional implications
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