Mar. 2021
Best presentation award

Mar. 2014
Best presentation award

Canine atopic dermatitis and cutaneous microbiome
Yoichiro Kasuga
Journal of Teikyo Heisei University, Mar. 2025

Scales in a dog after levothyroxine sodium treatment: A case report
Yoichiro Kasuga; Nobuo Murayama
Open Veterinary Journal, Oct. 2024, [Reviewed]
Background:
Scales are composed of exfoliated keratinocytes and are frequently a secondary change, requiring the determination of the underlying cause. Consequently, making an appropriate differential diagnosis of scales and determining treatment necessity based on the results is crucial in dermatological practice.

Case Description:
We present a 7-year-old, neutered male Toy Poodle examined at Myogadani Animal Hospital with chief complaints of exercise intolerance, unexplained weight gain, and dermatological signs, including symmetrical alopecia of the trunk. The dog was diagnosed with hypothyroidism and administered levothyroxine sodium. A significant number of scales were observed, primarily on the trunk, after one month of administration. The scales disappeared after only reducing the dose of levothyroxine sodium for three months. Additionally, hair regrowth was observed as the scales disappeared. In this case, the scales were primarily observed in the alopecia area of the trunk, where hair growth was subsequently noted. Hence, levothyroxine sodium administration was thought to not only facilitate hair regrowth but also influence skin turnover, causing the appearance of scales.

Conclusion:
Clinicians who treat hypothyroidism need to be cognizant that symmetrical scales, primarily located on the trunk, do not co-occur with other skin lesions, such as erythema, and are not itchy, may appear within a month. The scales will naturally disappear in such cases when hair growth is complete; thus, no additional treatment is required.

A case report of refractory canine atopic dermatitis successfully treated with adipose-derived mesenchymal stem cells
Yoichiro Kasuga; Takeo Ichinose; Hisashi Matsumoto; Takeshi Fukuda
The Japanese Journal of Veterinary Dermatology, Jun. 2024, [Reviewed]

Suppressive effect of Yokukansan on glutamate released from canine keratinocytes
Yoichiro Kasuga; Ailing Hu; Zenji Kawakami; Masahiro Tabuchi; Takuji Yamaguchi; Hiroyuki Kobayashi; Shigaku Ikeda
Open Veterinary Journal, Feb. 2024, [Reviewed]
Background:
Canine atopic dermatitis (CAD) is caused by skin barrier dysfunction due to allergen exposure. Excessive glutamate release in the skin is associated with delayed skin barrier function recovery and epidermal thickening and lichenification. Treatment with Yokukansan (YKS), a traditional Japanese medicine, reduces dermatitis severity and scratching behavior in NC/Nga mice by decreasing epidermal glutamate levels. However, the association between canine keratinocytes and glutamate and the mechanism by which YKS inhibits glutamate release from keratinocytes remains unknown.
Aim:
We aimed to investigate glutamate release from canine progenitor epidermal keratinocytes (CPEKs) and the inhibitory effect of YKS on this release. We also explored the underlying mechanism of YKS to enable its application in CAD treatment.
Methods:
Glutamate produced from CPEKs in the medium at 24 h was measured. The measurement conditions varied in terms of cell density and YKS concentration. CPEKs were treated with a glutamate receptor antagonist (MK-801), a glutamate transporter antagonist (THA), and a glutamate dehydrogenase inhibitor (epigallocatechin gallate; EGCG), and the inhibitory effect of YKS, YKS + THA, MK-801, and EGCG on this release was determined. MK-801 and glutamate dehydrogenase inhibitor were tested alone, and THA was tested in combination with YKS. Finally, glutamine incorporated into CPEKs at 24 h was measured using radioisotope labeling.
Results:
CPEKs released glutamate in a cell density-dependent manner, inhibited by YKS in a concentration-dependent manner. Moreover, YKS reduced the intracellular uptake of radioisotope-labeled glutamine in a concentration-dependent manner. No involvement of glutamate receptor antagonism or activation of glutamate transporters was found, as suggested by previous studies. Additionally, EGCG could inhibit glutamate release from CPEKs.
Conclusion:
Our findings indicated that glutamate release from CPEKs could be effectively inhibited by YKS, suggesting the utility of YKS in maintaining skin barrier function during CAD. Additionally, CPEKs are appropriate for analyzing the mechanism of YKS. However, we found that the mechanism of action of YKS differs from that reported in previous studies, suggesting that it may have had a similar effect to EGCG in this study. Further research is warranted to understand the exact mechanism and clinical efficacy in treating CAD.

Pinnae alopecia due to peripheral vascular dysfunction in three dogs
Ai Hasegawa; Tomoya Hoshino; Yoichiro Kasuga; Shinichi Ishimura; Kaoru Endo; Tomoya Izuka; Masahiko Nagata
The Japanese Journal of Veterinary Dermatology, Dec. 2021, [Reviewed]

Topical Glucocorticoids Induced Adrenocortical Suppression in Two Dogs
Yoichiro Kasuga; Tomoshige Baba; Yuri Oshima; Masahiko Nagata
The Japanese Journal of Veterinary Dermatology, Sep. 2015, [Reviewed]

Increased sensitivity in PCR detection of tdh-positive Vibrio parahaemolyticus in seafood with purified template DNA.
Hara-Kudo Y; Kasuga Y; Kiuchi A; Horisaka T; Kawasumi T; Kumagai S
Journal of food protection, Sep. 2003, [Reviewed]
PCR is an important method for the detection of thermostable direct hemolysin gene (tdh)-positive (pathogenic hemolysin-producing) strains of Vibrio parahaemolyticus in seafood because tdh-negative (nonpathogenic) V. parahaemolyticus strains often contaminate seafood and interfere with the direct isolation of tdh-positive V. parahaemolyticus. In this study, the use of PCR to detect the tdh gene of V. parahaemolyticus in various seafoods artificially contaminated with tdh-positive V. parahaemolyticus was examined. PCR was inhibited by substances in oysters, squid, mackerel, and yellowtail but not by cod, sea bream, scallop, short-necked clam, and shrimp. To improve detection, DNA was purified by either the silica membrane method, the glass fiber method, or the magnetic separation method, and the purified DNA was used as the PCR primer template. For all samples, the use of the silica membrane method and the glass fiber method increased detection sensitivity. The results of this study demonstrate that the use of properly purified template DNA for PCR markedly increases the effectiveness of the method in detecting pathogenic tdh-positive V. parahaemolyticus in contaminated seafood.

Small Animal Internal Medicine　　　　　　　　　　　　　　　
Contributor
Jun. 2024