From June 1990 to October 1998, 100 patients with adult-type atopic dermatitis (59 males and 41 females, 25±8 years) were admitted to our hospital to receive balneotherapy using Kusatsu hot-spring water. The atopic dermatitis in all but 9 cases occurred while the patients were still under 20 and had been refractory to various treatments including steroid ointment therapy over a long period of time. The patients took a 10-minute 40-42°C hot-spring bath followed by immediate application of white petrolatum 1-2 times daily for 75±46 days. The main components of the hot-spring water are aluminium, sulphates and chlorides, and its pH is 2.0. The skin symptoms of 79 of 100 cases (79%) were improved through the balneotherapy and furthermore pruritus was improved in 55 of the 79 cases (70%). The improvement of skin manifestations was supported by a significant decrease in serum LDH levels. In contrast, pruritus was not improved in the remaining 21 cases who showed no changes in skin symptoms and serum LDH levels. Moreover, changes in the number of Staphylococcus aureus on the skin surface were examined before and after balneotherapy. In the 69 cases examined whose skin symptoms were improved, many Staphylococci aureus were detected in 52 of the cases but not in the other 17 cases before starting balneotherapy. They disappeared in 24 cases and decreased in 18 cases of the 52 cases, but were not changed in the remaining 10 cases through the balneotherapy. On the other hand, the number of Staphylococcus aureus on the skin surface was not changed in 11 of the 14 cases examined whose skin symptoms were not improved. Our previous study reported that bactericidal activity against Staphylococcus aureus is expressed by the co-existence of manganese and iodide ions contained in the hot-spring water under an acidic (pH 2.0-3.0) condition. Thus, the mechanisms of the improvement of skin manifestations through the balneotherapy may be explained by considering bactericidal activity of Kusatsu hot-spring water against Staphylococcus aureus inducing acute flares of skin manifestations. Therefore, balneotherapy at Kusatsu can be useful for the treatment of refractory cases of adult-type atopic dermatitis as a suitable method of skin care.

The circumferences of chest, abdomen, thigh and calf during head-out water immersion up to chin level were measured in 8 healthy male subjects (age 35.4±1.6years old, body mass index 23.7±1.6kg/m²) in standing and sitting positions. The circumferences of chest, abdomen, thigh and calf decreased significantly during immersion in standing position. The circumferences of chest, abdmen and thigh decreased significantly in sitting position. The circumference of chest decreased from 90.6±3.4 to 90.1±3.1cm, that of abdomen decreased from 81.4±2.8 to 80.6±2.5cm, that of thigh decreased from 47.1±1.6 to 46.6±1.8cm, and that of calf decreased from 37.7±1.8 to 37.2±1.8cm during immersion in standing position. As the body surface area is about 1.6m², the decrease in the volume of human body is considered to be 730cm³ or less when the body shape change during immersion is not taken into considerarion.

This study investigated the existence of platelet activation before the onset of cerebral infarction, and analyzed the association between the platelet activation and the degree of atherosclerosis. Furthermore, prediction of the risk of cerebral infarction by assessing platelet activation was attempted. Thirteen patients with cerebral infarction, 7 patients with atherosclerosis and 8 healthy subjects were enrolled in this study. Ultrastructural shape change, peroxidase reaction, and fibrinogen content in the platelets were observed and plasma levels of thrombin antithrombin complex, α₂-plasmin inhibitor plasmin complex, β-thromboglobulin and platelet factor-4 were measured in patients with atherosclerosis and cerebral infarction at the acute, subacute and chronic phases. The ultrastructural shape change, peroxidase reaction, and fibrinogen content did not differ among acute, subacute and chronic phases of cerebral infarction. The frequency of platelet shape changes were also increased in patients with atherosclerosis, compared with healthy subjects. Plasma levels of β-thromboglobulin, platelet factor-4, and thrombin antithrombin complex increased only during the acute phase of cerebral infarction. It is suggested that platelet activation occurs before the onset of cerebral infarction and that platelet shape change is associated with the degree of atherosclerosis, or plaque stability. Platelet activation would be derived not from thrombotic event itself but from endothelial damage or pre-existing atherosclerosis. Platelet shape change, therefore, could predict the risk of cerebral infarction. Taken together with our previous reports demonstrating increased blood viscosity, noctural hypotension, increased human atrial natriuretic peptide, decreased fibrinolytic activity, and platelet shape change were observed after very hot hot-spring bathing, cerebral infarction in spa-resort could be caused partly by very hot hot-spring bathing after traveling on a tight schedule and alcohol drinking by elderly patients with atherosclerosis.

A 3-min bath in 47°C hot-spring water called ‘jikan-yu’ has been recommended for over 130 years at Kusatsu-spa. There is a traditional custom of pouring hot-spring water of the same temperature over the head before entering the bath to avert an afflux of blood to the brain. The medical significance of this custom was investigated in 8 healthy male volunteers (age 31±6 years and body mass index 22.4±1.6kg/m²). There were no significant differences in plasma levels of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), cortisol, and β-endorphin on a comparison of findings before and after the action of pouring 20 pails of 47°C hot-spring water over the parietal and occipital areas of the head. However, the direct effect of heat stress on the internal thermosensor in the anterior hypothalamus regulating heat loss and thermogenesis was not examined in this study. Thus, it is considered that the action does not provide a direct hyperthermal stimulus to the brain stem to release stress hormones but may dilate blood vessels of the head to prepare for the abrupt afflux into the cerebral circulation of blood heated by subsequent very hot hot-spring bathing.

We have investigated change in platelets and the blood coagulation and fibrinolytic systems as a mechanism of the onset of thrombotic diseases during and after hot-spring bathing. In this study, We examined effect of 10min 42°C and 37°C hot-spring bathing on protein C, protein S and antithrombin III in seven healthy male subjects. The mean values of protein C antigen, protein C activity, total and fee protein S antigens, protein S activity and antithrombin III activity were slightly increased by both methods, while these changes were not statistically significant. Taken together with our previous reports, 10min 42°C hot-spring bathing gives no effect on the blood coagulation system.

From March 1990 to September 2001, 24 patients with psoriasis (16 males and 8 females, 54±18 years) were admitted to our hospital to receive balneotherapy using Kusatsu hot-spring water. The psoriasis had been refractory to various treatments including steroid ointment therapy over a long period of time. The patients took a 10-minute 40-42°C hot-spring bath followed by application of vitamine D3 ointment 1-2 times daily for 37±19 days. The main components of the hot-spring water are aluminium, sulphates and chlorides, and its pH is 2.0. The skin symptoms of 20 of 24 cases (83%) were improved through the balneotherapy, while those of the remaining 4 cases were not changed. No side effects were observed. The serum levels of uric acid, GOT and GPT which are reported to be increased slightly did not correlate with the skin symptoms. The serum LDH level which is associated with the skin manifestastions in patients with atopic dermatitis also gave no useful information in the treatment of psoriasis. Although the mechanism of the improvement of skin manifestations is not clarified, balneotherapy at Kusatsu can be useful for the treatment of refractory cases of psoriasis as alternative and complementary medicine