The Evaluation of Usefulness of PAS Stain and GMS Stain as Clinical Diagnostic Methods of Tinea unguium / 대한의진균학회지

BACKGROUND: Tinea unguium is a common problem seen in clinical practice. Considering the many differential diagnoses of dystrophic nails, it is important to make a definitive diagnosis of dermatophyte infection before the initiation of antifungal therapy. Potassium hydroxide (KOH) preparation and fungal culture, which are commonly used in the diagnosis of these infections, often yield false-negative results. Recent reports have suggested that nail plate biopsy (Bx) using periodic acid-Schiff (PAS) (Bx/PAS) stain may be a very sensitive technique for the diagnosis of tinea unguium. OBJECTIVE: The purpose of this study was to evaluate the usefulness of PAS and Grocott's methenamine silver (GMS) staining of nail specimen in the diagnosis of tinea unguium as a standard method. METHODS: We evaluated 75 nail specimens from suspected tinea unguium using KOH preparation, biopsy using periodic acid-Schiff stain, and Grocott's methenamine silver stain. RESULTS: Of the 75 nails which were negative on potassium hydroxide mounting, 43 and 39 cases were tested positive respectively on periodic acid-Schiff stain and Grocott's methenamine silver stain. CONCLUSION: Bx/PAS and Bx/GMS are the sensitive methods for the diagnosis of tinea unguium. They are indicated if clinical suspicion of onychomycosis is high and KOH preparation shows no fungal elements.

The Effect of Botulinum Toxin Injection on Compound Action Potentials and Repetitive Nerve Stimulation in Rat Gastrocnemius Muscle

Botulinum toxin develops muscular paralysis through the inhibition of acetylcholine release from presynaptic membrane in neuromuscular junction. It has been used clinically to treat strabismus, blepharospasm and spasmodic dysphonia. Recently it was introduced for the treatment of limb spasticity as well. Serial compound muscle action potential(CMAP) amplitudes were measured and repetitive nerve stimulation test(RNST) was performed with 2Hz and 30Hz on the rat gastrocnemius muscle to observe the effect of muscle paralysis. Also, Periodic acid Schiff (PAS) staining sections of the muscle for glycogen was studied to quantify the degree of muscular paralysis. Thirty Sprague-Dawley rats, 10 for control and 20 for experimental group were studied for 12 weeks. Normal saline 0.025 ml and 0.125 ml was injected into gastrocnemius muscle in cotrol group 1 and 2, respectively. Botulinum toxin type A(Botox) was injected 5.0U/0.025 ml in experimental group 1, 2.5U/0.025 ml in group 2, 2.5U/0.125 ml in group 3, and 0.5U/0.025 ml in group 4. The amplitudes of CMAP declined markedly by 81.1% to 96.5% of basal amplitudes on the first week after Botox injection, but slightly recovered on 12th week by 20.8% to 42.2% with greater recovery in lower dose group. RNST with 2Hz produced no remarkable 1 : 5 amplitude change in experimental group. RNST with 30Hz produced marked increment in 1 : 5 amplitude up to 24.4%. PAS staining for muscle sections showed residual glycogen after tetanic stimulation due to neuromuscular block by Botox.