Noriko Ohtaki

Tyrosinase as glycoprotein

SummaryPurified tyrosinase T1 was incubated with neuraminidase. The catalytic activity of tyrosinase was essentially retained, after this treatment. The tyrosinase band (Dopa stained) was transformed into a new less anodic form, similar to tyrosinase T2, on disc electrophoresis. The band of protein was also converted to the same position as the Dopa stained.The other hand, the only one PAS stained band of native tyrosinase T1 was splitted into the three slower-moving bands. One was consistent with Dopa and protein stained bands. The other two were much moro slower than the former band and completely free of peptide and enzymic activity. The PAS-densitometric value of native tyrosinase T1 was almost equal to those of three separated bands in total.These results suggest that mammalian tyrosinase is a kind of glycoprotein.ZusammenfassungBei Inkubation von gereinigter Tyrosinase T1 mit Neuraminidase blieb die katalytische Aktivität von Tyrosinase im wesentlichen erhalten. In der Disc-Elektrophorese erschien das Tyrosinaseband (bei Dopa-Färbung) als neue, weniger anodische Form, ähnlich der Tyrosinase T2.Andererseits erschien das einzige PAS-gefärbte Band der nativen Tyrosinase T1 in Form von drei langsam wandernden Bändern. Eines davon entsprach Dopa und proteinhaltigen Bändern. Die beiden anderen wanderten wesentlich langsamer und waren frei von Peptiden und enzymatischer Aktivität. Die PAS-Dichtemeßwerte der nativen Tyrosinase T1 waren fast so groß wie die zusammengenommenen Werte der einzelnen Banden.Die Ergebnisse lassen vermuten, daß die Säugetier-Tyrosinase eine Art Glykoprotein darstellt.

Clinical observations of mosquito bite reactions in man: a survey of the relationship between age and bite reaction.

To evaluate the mechanism of mosquito bite reaction in man, the reaction to Aedes albopictus was observed in 162 subjects ranging in age between 1 to 68 years old. Bite reactions were found to consist of both an immediate and a delayed reaction. The eruption and time course of the immediate reaction were consistent with type I hypersensitivity. The eruption and time course of the delayed reaction were consistent with cutaneous basophil hypersensitivity. Positive rates of immediate reaction increased from early childhood to adolescence and decreased with age from adulthood. The appearance and intensity of the delayed reaction decreased with age. Mosquito bite reactions in human beings exposed continuously and regularly are known to change from stage 1 to stage 5 (stage 1; no reaction, 2; delayed reaction only, 3; immediate and delayed reaction, 4; immediate reaction only, 5; no reaction). Analysis of the relationship between age and bite reaction in this study indicated that the principle held true even when the exposures were irregular or at random.

Guideline for the diagnosis and treatment of scabies in Japan (second edition)

The guideline has been prepared by the Japanese Dermatological Association to ensure proper diagnosis and treatment of scabies, as oral therapy became available on August 2006 under health insurance and its clinical use was expected to increase. For making a proper diagnosis, the following three points should be taken into consideration: (i) clinical symptoms; (ii) detection of the mite (Sarcoptes scabiei); and (iii) epidemiological symptoms. The diagnosis is confirmed if the mites or eggs are identified by microscopy or dermoscopy and so forth. Topical sulfur preparations, with only limited usefulness, are the only available topical drugs approved by health insurance coverage for treating scabies. Currently, crotamiton, benzyl benzoate and γ‐benzene hexachloride are also used clinically. It is important to apply these to the whole‐body, including hands, fingers and genitals. The dose for ivermectin is a single administration p.o. of approximately 200 µg/kg bodyweight with water before a meal. Administration of a second dose is considered, if new specific lesions develop or the mites are detected. For treating crusted scabies, concomitant administration of oral ivermectin and the topical preparation is necessary. Some safe and useful topical drug preparations are needed to be approved by health insurance.

A case of crusted scabies with a bullous pemphigoid‐like eruption and nail involvement

We report a case of a 71‐year‐old man infected at a nursing home who developed a bullous pemphigoid‐like eruption with nail involvement. He was diagnosed by his family doctor as suffering from eczema and was treated with topical corticosteroids, then blisters started appearing. He was next diagnosed as suffering from bullous pemphigoid and treated with oral prednisolone, which worsened his condition. He was finally diagnosed as having crusted scabies with bullous pemphigoid‐like eruptions and nail involvement at our clinic. He was then prescribed oral ivermectin (two doses of 12 mg ivermectin with a 1‐week interval) and topical lindane (1%γ‐BHC in petrolatum) for scabies with 5% salicylic acid in plastibase as an additional treatment for the crusted lesions on his soles. He showed remarkable improvement in 2 weeks, and his nails showed complete recovery after 7 weeks of occlusive dressing treatment with 1%γ‐BHC. One and a half years later, the patient showed no sign of a recurrence of scabies. The histology of a blister taken from this patient was similar to that of bullous pemphigoid. Direct immunofluorescence showed immunoglobulin (Ig)G and C3 deposition at the dermoepidermal junction similar to that of bullous pemphigoid, but indirect immunofluorescence was negative. The bullous symptoms of this patient were considered to be due to the scabies, because the patient recovered completely after receiving treatment for scabies. Indirect immunofluorescent study is important to distinguish between scabies with blister formation and true bullous pemphigoid.

Risk factors of scabies in psychiatric and long-term care hospitals: a nationwide mail-in survey in Japan.

Despite the commonness of scabies in Japanese institutional settings, the nationwide prevalence of scabies has not been elucidated. This study was conducted to assess the prevalence of scabies and control measures in Japanese hospitals. A questionnaire on scabies epidemiology (e.g. number of patients and onsets of outbreak) and preventive measures were sent to psychiatric hospitals and long‐term care hospitals nationwide (n = 1795) in January 2005. Seven hundred and forty‐one hospitals responded (41.3%). Three hundred and thirty‐three (44.9%) respondent hospitals had one or more scabies cases in 2004. Among 159 hospitals that had experienced scabies outbreak, only 32 of them reported cases of crusted scabies. Multivariate regression analysis showed that hospitals had a greater number of beds, and that acute‐ and long‐term care wards were more likely to experience scabies onsets. Hospitals that compiled their infection control manuals on scabies, treated suspicious patients with scabicides without confirmed diagnosis, and performed skin checkup of inpatients were more likely to experience scabies cases. Infection control personnel should be aware that unrecognized crusted scabies can cause outbreaks. Higher patient turnover is a risk factor for scabies introduction into a hospital. Preventive measures against scabies, such as patient screening at admission and treating all suspicious patients without confirmed diagnosis, were not effective to avoid scabies introduction.

Oral Ivermectin Treatment in Two Cases Of Scabies: Effective in Crusted Scabies Induced by Corticosteroid but Ineffective in Nail Scabies

We report two cases of scabies treated with oral ivermectin (200 μg/kg). Case 1, a 72‐year‐old man, developed crusted scabies with the use of oral corticosteroids due to a misdiagnosis by an earlier physician. The patient was successfully treated with two doses of oral ivermectin at a 7 day interval with concomitant topical use of crotamiton and keratolytic agents. However, the nail scabies in this patient failed to respond to these treatments. Live mites were detected from all his toenails two weeks after the second dose of ivermectin. A complete cure of the nail scabies was achieved by occlusive dressing of 1% γ‐BHC on all toenails for one month. Case 2, a 52‐year‐old woman, had been treated with oral corticosteroid for mesangial nephritis. She developed common scabies, but a topical scabicide, crotamiton, was not effective. Two weeks after treatment with a single dose of oral ivermectin, eggs were still detected from a burrow on her trunk. Her treatment was completed after a further two doses of oral ivermectin were administered at 7 day intervals. In both patients, the administration of oral ivermectin did not induce any clinical or laboratory side effects. Oral ivermectin is effective for crusted scabies, but not effective for nail scabies. Two doses of oral ivermectin, administered with a one‐week interval, is an appropriate treatment regimen.

Immunoglobulins Specific to Mosquito Salivary Gland Proteins in the Sera of Persons with Common or Hypersensitive Reactions to Mosquito Bites

Using the immunoblot technique, we analyzed the quality and quantity of IgG, IgG4, and IgE specific to mosquito salivary gland (hereafter abbreviate as SG) components of Aedes albopictus in the sera of volunteers with common reactions and of 3 patients with severe reactions.

Cutaneous Reactions Caused by Experimental Exposure to Jellyfish, Carybdea rastonii

Dermatitis caused by contact with tentacles of jellyfish was studied on 25 volunteers. Two tentacles cut from a living jellyfish, Carybdea rastonii, were applied on each of the forearms and skin reactions were observed.

Delayed Flare-up Reactions Caused by Jellyfish

Four patients had a recurrence of cutaneous lesions 1 week after being stung by jellyfish. Three patients had flare-up lesions after only one exposure to jellyfish. All of the recurring lesions were vesicular erythema, and the histological findings of case 3 corresponded to that of allergic contact dermatitis.

A quantitative study of specific immunoglobulins to mosquito salivary gland antigen in hypersensitive and common types of mosquito bite reaction

This study was designed with two purposes: first, to elucidate immunologic mechanisms in different cutaneous reactions, particularly in hypersensitivity to mosquito bites, and, second, to develop a more reliable and safer method of identifying the causative species of mosquito in severe cases.