[Nuclear medicine of bone]

Bone scintigraphy using 99mTc-labeled phosphorous compounds was found to be the most frequently ordered nuclear medicine examination in a nationwide survey in Japan, and has been used for the detection of lesions and the evaluation of disease progression and response to therapy in various skeletal diseases. In this article, we review improvement of the diagnostic sensitivity and specificity for bone metastasis of not only nuclear medicine techniques, such as planar imaging, SPECT, early flow phase imaging and quantification of bone scintigraphy, and bone marrow scintigraphy but also such recently developed methods as bone mineral measurement, and bone metabolic marker assays. In addition, radionuclide therapy of intractable bone pain due to bone metastasis is also addressed.

Income elasticity of education and smoking

The relationships among the income (expenditures) level, expenditure for education and tobacco consumption were analyzed based on the data of workers households reported in Family Income and Expenditure Survey of Japan between 1980 and 1995. For all the observed years, elasticities of tobacco to living expenditure were less than -0.4 and the deviation from zero point had increased (-0.41 in 1980, and -0.95 in 1995). By contrast, elasticities of education to living expenditure were over 1.5 for the observed period. In the case of income elasticity, values of tobacco were negative with the same chronological tendency as in elasticity to living expenditure and those of education were around 1.10. The findings regarding the relationship between income level and tobacco consumption was quite different from most of the studies conducted in western countries, which suggested a positive elasticity between the two. According to the present results, we discussed two strategies in order to reduce the smoking prevalence rate in Japan: education and an increase in the cigarette price by higher cigarette taxes.

Clinical evaluation of a portable digital hearing aid with narrow-band loudness compensation

A new portable digital hearing aid referred to as CLAIDHA (Compensate for Loudness by Analyzing Input-signal Digital Hearing Aid), which employs frequency-dependent amplitude compression based on narrow-band loudness compensation, was clinically evaluated in 159 subjects with hearing loss. The results of speech tests revealed better intelligibility compared with the subject's own hearing aids; the advantage of using CLAIDHA in daily life was also indicated by the results of a questionnaire completed by the subjects. In about 64% of the subjects with a flat, gradually sloping type of hearing loss, CLAIDHA was satisfactorily adopted for daily use. However, in the subjects with a steeply sloping type of hearing loss and subjects with losses mainly at high and low frequencies, with near-normal mid-frequency hearing. this loudness compensation scheme seems to be slightly less effective.

T cell epitopes in Japanese cedar (Cryptomeria japonica) pollen allergens: choice of major T cell epitopes in Cry j 1 and Cry j 2 toward design of the peptide-based immunotherapeutics for the management of Japanese cedar pollinosis

Japanese cedar pollinosis is caused by exposure to Japanese cedar (Cryptomeria japonica) pollen, of which two components, Cry j 1 and Cry j 2, are believed to be the major allergens. T cell lines specific to either Cry j 1 or rCry j 2 were reactive to various portions of each panel of overlapping peptides derived from Cry j 1 or Cry j 2. Two peptides, p211-225 and p108-120, from among six major T cell epitopes identified in Cry j 1 sequence, and three peptides, p182-200, p344-355, and p66-80, from among five in Cry j 2, were chosen to design an artificial polypeptide (named Cry-consensus) based on a difference among the types of the restriction molecules capable of presenting these peptides. After construction of a DNA encoding these peptides in order, Cry-consensus was expressed in Escherichia coli. Five of six T cell epitopes, except for Cry j 2 p344-355, in Cry-consensus were recognized by the T cell clones specific to each peptide. PBMC from allergic patients induced higher proliferation under stimulation from Cry-consensus than individual peptides. Eighty-eight percent of the PBMC (15 of 17) showed proliferation under the Cry-consensus stimulation. Thus, several major T cell epitopes from Cry j 1 and Cry j 2 can be chosen in the design of peptide-based immunotherapeutics for the management of Japanese cedar pollinosis in subjects having various types of HLA class II molecules.

[X-ray absorptiometry]

Bone mass measurements are essential in the diagnosis of osteoporosis, the monitoring of its progression, and the evaluation of therapeutical responses. Among various methods of bone mass measurements, single- and dual-X-ray absorptiometry, SXA and DXA, have shown excellent fundamental performance. In this paper, the principles of SXA and DXA; i.e., factors of fundamental performance, such as precision, data-acquisition, and radiation dose, the practice of DXA, recent advances in DXA, such as the lateral spine scan, the measurement of body composition, application to BMD measurement of the bones of small animals and at sites of metal implants, morphometry of the spine, and geometrical measurement in the proxial femur, and clinical applications to osteoporosis were particularly reviewed.

Calcaneus as a site for the assessment of bone mass

The calcaneus is a skeletal site frequently used for monitoring bone loss after spaceflight, because it is sensitive to microgravity-induced bone mineral loss and reflects the degree of demineralization in the vertebra and the femoral neck. In this article, methods for assessing the calcaneus are reviewed, and their potential applications and limitations as the monitoring site for bone loss in weightlessness are discussed. Currently, single or dual energy X-ray absorptiometry appears to be most sensitive for monitoring bone mineral loss in weightlessness. The results of recent studies suggest two- to threefold longer follow-up times required for ultrasound techniques. However, ultrasound devices can be designed to be portable, making them attractive for inflight use, and ultrasound techniques are expected to provide information related to bone quality. Additional investigations that assess new ultrasound techniques would be important to determine and utilize the full potential of this technology for monitoring bone loss in weightlessness.

Characteristics of prehospital cardiac arrest patients in Japan and determinant factors for survival

Two hundred forty-seven consecutive patients who had prehospital cardiac arrest and were transferred to a municipal hospital were studied to elucidate the characteristics of these patients and to investigate factors for improving the survival rate among prehospital cardiac arrest patients. Detailed information on 130 patients with cardiac etiology was analyzed: 110 were confirmed dead in the emergency department (group A); 14 survived less than 1 week (group B); 6 survived longer than 1 week (group C). Only one patient received cardiopulmonary resuscitation (CPR) from a bystander, and none received electrical defibrillation before arriving at hospital because, at the time, emergency personnel were not allowed to perform advanced life support (ALS) in Japan. The three characteristics for better prognosis after prehospital cardiac arrest were found to be as follows: being witnessed on collapse, receiving prompt ALS, and ventricular fibrillation on arrival at hospital. The survival rate would have been higher if more lay people could have performed CPR and if emergency unit personnel had been allowed to perform ALS.

Bone mineral measurement in Japan

Various methods for evaluating bone mineral in appendicular, and axial bone or in the whole skeleton have recently become available. As bone mineral is one of the major determinants of bone strength, its exact measurement should be useful for the diagnosis of osteoporosis, as well as for the prediction of fracture risk and monitoring of therapeutical response. The aims of this paper are to review the fundamental performance of bone mineral measurements, the improvements in DXA systems, and the progress in site-specific bone mineral instruments for the radius and calcaneus used in Japan, and to introduce diagnostic criteria for primary osteoporosis, and report on annual rates of bone loss in Japanese females.

Prevalence of activated protein C resistance in acute myocardial infarction in Japan

To investigate the possibility that activated protein C (APC) resistance due to the factor V could be an important predisposing factor in acute myocardial infarction (AMI), we have retrospectively examined the prevalence of APC resistance with protein C, protein S and antithrombin III deficiency and antiphospholipid antibody syndrome in AMI patients (< or = 50 years) admitted to our hospital over the past 7 years. Forty-seven patients were enrolled in the study. We divided the patients into two groups, warfarin group (group A) and a non-warfarin group (group B). APC resistance is defined as when the APC ratio is below or equal to the cut-off value 2. APC resistance was not detected in either group. The prevalence of an APC ratio below or equal to 2.5 was 16.7% (1 case) in group A and 24.4% (10 cases) in group B. The prevalence of protein C deficiency was 5.0% (2 cases) in group B. Two cases (5.0%) in group B had protein S deficiency. Antithrombin III deficiency was not detected in either group. The prevalence of antiphospholipid antibody syndrome measured by APTT was 40.4% (19 cases). We compared the AMI patients with 97 healthy volunteers (< or = 50 years old) without any thromboembolic events or bleeding tendency in their past history. No significant difference were found between these groups and the volunteers. APC resistance is a major cause of venous thromboembolism in Europe and the United States, while in Japan it is believed to be a minor cause of arterial thromboembolism.

[Comparative study on the tumor accumulation of 99mTc-tetrofosmin and 99mTc-MIBI in rabbits bearing VX-2 cancer]

Each of myocardial blood flow imaging agents has a potential usefulness as an agent for tumor scintigraphy. The tumor accumulation and washout of 99mTc-tetrofosmin and 99mTc-MIBI were comparatively studied using rabbits bearing VX-2 cancer. From seventeen to twenty days after the implantation of VX-2 cancer into the femoral region of seven rabbits, tumor to soft tissue accumulation ratio (T/S ratio) of each agent was calculated in early images (5 min after injection) and in late images (50 min after injection). Compared with 99mTc-tetrofosmin, the T/S ratio of 99mTc-MIBI was higher and, moreover, the washout was delayed. These results suggest that there is a difference in tumor accumulation property between these two agents.

[Compartment analysis of 123I-iomazenil brain on early and delayed SPECT]

We investigated the characteristics of 123I-Iomazenil (IMZ) SPECT images in 12 adults (six males and six females, with a mean age of 56.1 years). The washout rate of 123I-IMZ from the brain was estimated from two SPECTs done 15 min and 3 hr after injection. Although the washout was relatively slow, the rates differed in each intracerebral region, suggesting that the distribution of 123I-IMZ was gradually changing. Furthermore, assuming 123I-IMZ kinetics in the brain for the three-compartment, two-parameter model, the transition rate constant (K1) from the blood to the brain and the binding potentials (BP) of benzodiazepine to the receptor were calculated. The BP and K1 values were compared with 123I-IMZ SPECT counts and CBF values by 123I-IMP. The BP values correlated more closely with the counts on the delayed SPECT than those on the early SPECT. It was confirmed that delayed SPECT images reflect better the distribution of the benzodiazepine receptor than early images do. On the other hand, the K1 values correlated highly with CBF obtained by 123I-IMP, and this finding suggested that super-early SPECT images might be remarkably influenced by the distribution of CBF.

A case of amiodarone-induced thyrotoxicosis successfully treated with prednisolone

We describe a patient who was treated with amiodarone for ventricular arrhythmia based on arrhythmogenic right ventricular dysplasia and who subsequently developed severe amiodarone-induced thyrotoxicosis. Discontinuation of amiodarone resulted in sustained ventricular tachycardia, which was successfully treated with a DC electrical shock, and subsequently atrial fibrillation, leading to brain embolism due to occlusion of the left middle cerebral artery. Combination treatment with amiodarone and prednisolone was effective both in reducing the serum concentration of thyroid hormones and in improving the patient's general condition. As the use of amiodarone becomes more widespread, treatment with prednisolone for this kind of thyrotoxicosis, which is resistant to conventional treatment, will be required increasingly frequently because iodine overload of the thyroid gland persists for some time after discontinuation of amiodarone treatment.

Frequency of contact with cigarette advertising and smoking experience among young women in Japan

Cigarette advertising plays a crucial role in adolescent smoking. A survey with a self-administered questionnaire was conducted to 198 female nursing students in Kitakyushu City in 1996 to provide primary data on the young women's contact with cigarette advertising in various media in Japan. The proportions of respondents who had seen cigarette advertising on TV and that on billboards were both over 95% of the effective respondents, the highest among all the media, followed by magazines, newspapers and the radio. The proportion of respondents who "frequently" had contacts was the highest by TV, followed by billboards, newspapers, magazines and radio. Over 50% of students who had past/current smoking experience felt that they were "frequently" exposed to cigarette advertising, and, on other hand, approximately 50% of those who had never smoked felt that they "occasionally" saw cigarette advertising, on both TV and billboards. In Japan, young women seem to be heavily exposed to cigarette advertising through various media. This study implies that TV and billboards are the most frequently contacted media of cigarette advertising and perhaps the most influential to smoking among young people.

Age-related changes in vertebral height ratios and vertebral fracture

Because no gold standard for the definition of vertebral fracture exists, there has been controversy about whether mild vertebral deformities are truly fractures or simply normal variation in vertebral size and shape. The aim of this study was to assess the associations of mild variations of vertebral height ratios to definite vertebral fractures. In 479 Japanese women (aged 53.9 +/- 9.1 years) who visited our institute for a medical checkup, we performed lateral lumbar radiographs and morphometric parameters were derived by measuring the anterior (Ha), middle (Hm) and posterior (Hp) height of each vertebral body from T12 to L4. Vertebral height ratios, Ha/Hp, Hm/Hp or Hp/Hp' of adjacent vertebrae that were more than 3 SD different from vertebra-specific means of normative data were considered to indicate fractures. Forty-five women were diagnosed with at least one fracture. After excluding the subjects with vertebral fracture, we examined the associations of the variations in vertebral height ratios with age, anthropometric parameters and lumbar bone mineral density (BMD) measured by dual-energy X-ray absorptiometry. Vertebral height ratios, especially Hm/Hp in postmenopausal women, tended to decrease with age and were positively associated with BMD. No significant correlation was observed between anthropometric parameters and vertebral height ratios. Aged-related decrease in vertebral height ratios (Ha/Hp and Hm/Hp, each averaged from T12 to L4) was significant even after the correction for BMD. Mean values of height ratios of non-fractured vertebrae adjusted for age and BMD were significantly lower in postmenopausal women with vertebral fracture than in those without vertebral fracture. Logistic regression analysis showed that BMD and height ratios of non-fractured vertebrae were independent predictors of vertebral fracture risk. The results suggest that older women, and women with at least one obvious (3 SD) fracture, tend to have mild deformities which do not qualify using the 3 SD definition. These mild deformities may represent real consequences of osteoporosis, because they are more pronounced among women with obvious fracture.

I-123 iodoamphetamine scintigraphic detection of bone metastases from malignant melanoma

Widely used for cerebral perfusion imaging, I-123 iodoamphetamine (I-123 IMP) is also known to accumulate in malignant melanomas. A case of malignant melanoma is presented, in which I-123 IMP scintigraphy was useful to visualize the bone metastases. During the period of postoperative follow-up, multiple foci of increased I-123 IMP uptake appeared in the skeleton. Conventional bone scintigraphy was less striking, showing cold defects or irregular radionuclide uptake.

Japanese cedar pollinosis and HLA-DP5

Japanese cedar pollinosis is a type I allergic disease caused by Japanese cedar (Cryptomeria japonica) pollen. We investigated the association between the disease and HLA class II alleles by HLA-DNA typing using a PCR-SSOP method and found that the frequency of HLA-DP5 (DPA1*02022 and DPB1*0501) was significantly increased in the patients. To investigate whether the HLA-DP5 molecule is directly involved in the pathogenesis of the disease, Japanese cedar pollen antigen (CPAg)-specific T cell lines were established from 3 patients who possessed HLA-DP5 (DPA1*02022/ DPB1*0501). By using these CPAg-specific T cell lines and HLA class II-expressing L-cell transfectants, we found that disease-associated HLA-DP5 restricted T cells specific for CPAg existed in the patients. Furthermore, among 38 synthesized overlapping peptides spanning the entire length of one of the major Japanese cedar pollen allergens, Cry j 1, an immunodominant peptide which induced HLA-DP5 restricted Th2 was identified. These observations suggest that the HLA-DP5 may be involved, at least in part, in the pathogenesis, by helping the IgE antibody production against CPAg.

Diagnostic significance of thrombin-antithrombin III complex (TAT) and D-dimer in patients with deep venous thrombosis

Thrombin-antithrombin III (TAT) and D-dimer were measured in 50 patients suspected of deep venous thrombosis (DVT) to assess the usefulness of these indicators in the diagnosis of DVT. DVT was diagnosed by ultrasonography (compression method and Doppler imaging). In patients who were negative for DVT (Group A), TAT was 3.8 +/- 2.36 micrograms/L (mean +/- SD) and D-dimer was 0.7 +/- 0.69 micrograms/ml, whereas in patients diagnosed with DVT (Group B), TAT was 20.4 +/- 19.10 micrograms/L (p < 0.001) and D-dimer was 9.0 +/- 9.21 micrograms/ml (p < 0.001). Thus, Group B had significantly higher levels of both markers. Moreover, 19 of the 23 cases in Group B had acute DVT, with symptoms appearing within 2 weeks of onset. When the cutoff for a positive diagnosis of DVT was set at TAT of 7.0 micrograms/L or more and D-dimer of 3.0 micrograms/ml or more, sensitivity was 84%, specificity was 96%, and accuracy was 90%. Based on these results, we concluded that TAT and D-dimer are extremely useful in screening for acute DVT.

Purification, characterization and molecular cloning of Cha o 1, a major allergen of Chamaecyparis obtusa (Japanese cypress) pollen

Pollen of Chamaecyparis obtusa (Japanese cypress) is one of the causes of allergic pollinosis in Japan. A major allergen of the pollen designated Cha o 1, was purified by two-step ion exchange chromatography. Cha o 1 was separated into four components with molecular masses of 48.5 kDa and 52.0 kDa, each with pIs of 6.77 and 6.82. The 23-residue N-terminal sequence of Cha o 1 was determined and shown to have high identity with that of Cry j 1, a major allergen of Cryptomeria japonica pollen. cDNA coding for Cha o 1 was cloned by hybridization screening using Cry j 1 cDNA as a probe. One of the cDNA clones, pCHA-1 was sequenced and found to code for a putative 21-residue signal peptide and a 354-residue native protein with a derived molecular mass of 38.1 kDa. The deduced amino acid sequence of Cha o 1 showed 79-80% identity with those of Cry j 1. These findings were consistent with observations of a close crossreaction between the two allergens. Homology analyses revealed that Cha o 1 had 46-49% identity with Amb a 1 families and Amb a 2, the major allergens of short ragweed. Cry j 1 has pectate lyase enzyme activity, suggesting that Cha o 1 may have the same enzyme activity as Cry j 1.

Influence of exercise and degenerative vertebral changes on BMD: a cross-sectional study in Japanese men

The effects of recreational exercise and milk intake on BMD were assessed in Japanese men using analysis of covariance with significant predictor variables, selected from age, height, body weight and body mass index (BMI), as covariates. The influence of degenerative vertebral changes on these effects was also evaluated. Recreational exercise was found to be positively associated with BMD at the lumbar spine and the femoral neck, whereas milk intake, a possible indicator of calcium intake in the Japanese, was positively associated with BMD at the radius and the lumbar spine. Not only vertebral BMD but also radial and femoral neck BMD was higher in the subjects with osteophytosis or sclerosis in the lumbar vertebrae. Neither exercise nor lumbar pain was significantly related to these vertebral changes. These data suggest a protective effect of regular recreational exercise and milk intake on bone health in Japanese men.

[Effects of tobacco advertising regulations in various countries]

The massive increase of tobacco-attributable deaths has been a great concern in the world. Although many factors are associated with tobacco use, advertising has played a crucial role, and restriction of advertising is a possible legislative option to control the tobacco epidemic, especially in younger populations. Scientific literature was reviewed to evaluate the effect of tobacco advertising restrictions in various countries. Studies in some developed countries suggest that properly implemented total advertising bans could reduce tobacco consumption and smoking prevalence. On the other hand, the effects of partial advertising bans, such as those in the United States, is controversial. Following partial restrictions, the tobacco industry quickly shifted its advertising focus to other options, such as the print media or sports sponsorship. This shift of focus of advertising to less restricted measures made the effects of partial advertising bans less definitive. In addition, sound consideration on some methodological issues, such as selection of appropriate variables and data validity, is required for the proper assessment of the effect of tobacco advertising restrictions. No legislative restrictions for the tobacco advertising are implemented in Japan although several self-regulations by the tobacco industry circumscribe the content of advertising and the appearance of broadcast advertising. The governmental task forces encourage further restrictions of tobacco advertising through voluntary self-regulation by the industry, and not by governmental legislative actions. Further research on tobacco advertising in Japan, such as its influence on juvenile smoking and social norms and the effectiveness of voluntary self-regulation, is required to develop appropriate policies on tobacco advertising control.

Urinary excretion of type I collagen crosslinked N-telopeptides in healthy Japanese adults: age- and sex-related changes and reference limits

A new immunoassay for measuring urinary excretion of type I collagen crosslinked N-telopeptides (NTx) has been reported to be a specific and sensitive method for assessing bone resorption. We have studied factors affecting biological variations in urinary NTx excretion in a population of 452 healthy Japanese adults, comprising 238 men and 214 women, 20-79 years of age. Urinary NTx excretion increased significantly with age in women (> or = 25 years of age) (r = 0.55, p < 0.0001) and modestly correlated with lumbar bone mineral density (L-BMD) in both sexes (> or = 25 years of age) (r = 0.31, p < 0.0001 for men; r = 0.50, p < 0.0001 for women). Urinary NTx levels in women were significantly higher than in the corresponding male age groups after the fifth decade (p < 0.0001). None of the anthropometric variables (weight, height, and body mass index) showed a linear effect on the urinary NTx excretion independent of age and L-BMD. In women, menopause was reflected by a twofold increase in urinary NTx excretion, from a mean of 28-59 pmol bone collagen equivalents (BCE)/mumol creatinine, and this menopause-related increase persisted for the entire postmenopausal period. In postmenopausal women, the interindividual variations of urinary NTx excretion were much more marked than in men and in premenopausal women. Moreover, in the subgroups of pre- and postmenopausal women, urinary NTx excretion correlated with neither age nor L-BMD. These data show that the major biological factor that modifies urinary NTx level is menopause and suggest that the bone turnover rates in the elderly women are increased, on average, irrespective of bone mineral density.