Ryoji Tsuboi’s research while affiliated with Tokyo Medical University and other places

The present case series examined five instances of psoriasiform drug eruption diagnosed between 2014 and 2022 at the study site and 23 cases of drug eruption manifesting psoriasiform lesions which had been reported between 1986 and 2022. The causative drug, distribution of the skin eruptions, clinical latency to eruption, treatment course, and histopathological findings were investigated. The most common causative agents were calcium channel blockers (CCB) (64.5%). Of the 28 cases of psoriasiform drug eruption for which details of the eruption sites were reported, 46.4% occurred on the face, which was slightly higher than the usual distribution of psoriasis. CCB were responsible for 80.0% of the cases of facial skin rash. The mean time from the administration of the suspected drug to eruption onset was 25.0 months (range: 0.5–120 months; median: 13.0 months). In all the cases, the skin rash improved after the causative drug was discontinued. CCB were the most common causative agent, and the eruptions more commonly occurred on the face than in normal psoriasis, suggesting that it is especially important to confirm whether there is a history of CCB administration in psoriasis patients with extensive, facial skin eruptions.

A previous, proof-of-concept clinical study suggested that dermal sheath cup cell injections into the affected areas of male/female pattern hair loss (PHL) may have some amelioratory effects, the clinical efficacy of which needs further examination. A phase III equivalent clinical study was conducted to further probe the therapeutic potential of this novel approach and verify its safety and efficacy in improving the appearance of PHL. Thirty-six participants with PHL were injected with dermal sheath cup cell harvested from non-affected occipital hair follicles twice in quarterly intervals. Global photographic assessment and phototrichogram were performed in a blinded manner. Patient-reported outcomes were assessed for 12 months. On global photographic assessment, 30% of the participants showed improvement. The analysis of phototricogram data detected the increases in the cumulative hair diameter, hair cross-sectional area, and mean hair diameter of 107.6 ± 152.6 μm/cm2 , 13069.1 ± 10960.7 μm2 /cm2 , and 0.9 ± 0.9 μm (ratios vs. baseline: +1.4%, +3.4%, and +2.2%), respectively. The female and high terminal hair ratio groups achieved better improvement. Of the total participants, 62.9% noted some degree of improvement. No serious adverse events were detected. This novel approach exhibited visible effects while ensuring safety and patient satisfaction. Therefore, it holds promise as a possible therapeutic option for treating PHL, especially in women.

The dermal sheath (DS) cells are present in a sheath-like connective tissue on the outermost side of the hair follicle; DS connects to the dermal papilla (DP) in the lower part of the hair bulb. The ability of DP cells to induce and regenerate hair follicles has been demonstrated in a great number of studies as discussed in other chapters. In this chapter, the characteristics and functions of DS cells in hair follicle regeneration have been reviewed. The potential of a clinical application using DS cells for male and female pattern loss is also discussed in this chapter. The PubMed database was used for the selection of papers with keywords including ‘dermal sheath’, ‘connective tissue sheath’, and ‘hair’. Through a comprehensive reading of the abstracts, papers on hair follicle regeneration were further selected and cited. Several papers have shown that DS cells can induce growth of new hair follicles. Recent studies reported the presence of hair follicle dermal stem cells in the DS, suggesting these may be responsible for hair follicle regeneration. Based on these properties, clinical studies have been conducted on male and female pattern hair loss using lower DS cells. The initial results from these studies show safety and some efficacy of lower DS cells in hair follicle regeneration. In conclusion, several rodent studies have shown that the DS and cells derived from it have both hair regenerative and skin regenerative potential. Further studies characterizing human DS cells and identifying if there are human hair follicle dermal stem cells need to precede further understanding of human hair follicle regeneration, for the development of an efficient clinical application for male and female pattern hair loss.

Background/aim: MST-16 and VP-16, both of which are topoisomerase II inhibitors, are antitumor agents regularly used to treat malignant lymphoma and small cell lung carcinoma. New therapeutic agents for tumor stage mycosis fungoides (MF) have recently been developed, but their efficacy is limited. We herein retrospectively reported the use of MST-16/VP-16 combination therapy for tumor stage MF at multiple treatment centers and examined their antitumor effect. Methods: Five male and four female patients with tumor stage MF were enrolled. Age at the start of therapy ranged from 33 to 80 years (average: 54.5 years), and the previous treatment consisted of R-CHOP, CAVOP-IFN, etc. The protocol for low-dose MST-16/VP-16 combination chemotherapy consisted of 800 mg MST-16 and 25 mg VP-16 administered 5 days per month. Results: Three of the 9 patients died, but two of the three fatalities were unrelated to MF. A treatment effect was seen in three and 6 patients who showed a complete response and a partial response, respectively. The 5-year and 10-year overall survival rate was 85.7% and 57.1%, respectively. Adverse reactions consisted of 4 cases of nausea and 1 case of leukopenia. Conclusion: The present study demonstrated that the response rate to MST-16/VP-16 combination therapy was 100% and that the treatment effect was relatively long, suggesting that this therapy may be a viable option for treating tumor stage MF.

Onychomycosis with longitudinal spikes in the nail plate has been reported to be refractory to oral drugs as with dermatophytoma. We evaluated the efficacy of 10% efinaconazole solution in the treatment of onychomycosis with longitudinal spikes. Of the 223 subjects who were enrolled in a previous study, a post-hoc analysis of 82 subjects with longitudinal spikes was performed in this study. The opacity ratio of longitudinal spikes was decreased over time from 8.1 to 0.9 at the final assessment. In addition, the longitudinal spike disappearance rate increased early after the application to 81.7% at the final assessment. Therefore, 10% efinaconazole solution can be a first-line drug for longitudinal spikes, which have been regarded as refractory to oral drugs.

Tinea unguium is a common nail disease caused by dermatophytes. Although direct potassium hydroxide (KOH) microscopy and fungal culture are considered the gold standard for diagnosing this disease, their accuracy is insufficient. A lateral flow immunochromatographic assay (LFIA) kit, using a monoclonal antibody against Trichophyton rubrum, was developed and its sensitivity was recently improved 50% in vitro relative to its earlier version. The present study aimed to validate the clinical utility of this improved LFIA kit for diagnosing tinea unguium in comparison with direct KOH microscopy. A similar trial was simultaneously performed using scale samples from patients with tinea pedis to determine the assay’s diagnostic potential. Nail samples, approximately 2 mg in weight, were collected from 112 non‐treated tinea unguium patients and 56 non‐tinea unguium patients. Samples from 25 tinea pedis patients and 20 non‐tinea pedis patients were also collected. The sensitivity and specificity of the LFIA kit for tinea unguium was 84.8% (95/112) (95% confidence interval [CI], 76.8–90.9) and 83.9% (47/56) (95% CI, 71.7–92.4), respectively. The inconsistency rate was 15.5% (26/168) (95% CI, 10.4–21.9). The sensitivity and specificity of the LFIA kit for tinea pedis was 84.0% (21/25) and 100.0% (20/20), respectively. These results suggest that for diagnosing tinea unguium, the LFIA kit is a useful supplement to, but not a replacement for, direct KOH microscopy. For definitive diagnosis of suspected cases, appropriate sampling, repeated examinations, and a combination of diagnostic techniques are essential.