Influence of years engaged in agriculture and number of pregnancies and deliveries on mortality of inhabitants of the Jinzu River basin area, Japan

BACKGROUND

The occurrence of itai-itai disease is thought to be affected by such factors as pregnancy, lactation, hormonal disorders, aging, and calcium deficiency.

AIMS

To study the influence of years engaged in agriculture and number of pregnancies and deliveries on the mortality of inhabitants of the Jinzu River basin area, which has been an endemic region for itai-itai disease.

METHODS

From 6,667 participants (3,181 men, 3,486 women; participation rate 93.4%) in the 1967 health survey, 3,639 subjects (1,591 men, 2,048 women) whose years engaged in agriculture were established, and 2,559 women/2,410 women with a known number of pregnancies/deliveries were selected as the target population. These data were confirmed on the basis of self reported replies confirmed afterwards by interview. The survival survey was conducted for 6,127 days from 1 August 1967 to 10 May 1984. Subjects were divided according to three water systems: the Jinzu River, non-Jinzu River, and mixed water system; the influence on mortality of the years engaged in agriculture and the number of pregnancies/deliveries was analysed using a Cox's proportional hazards model according to the water systems.

RESULTS

The mean years engaged in agriculture and mean number of pregnancies/deliveries were not different among the three water systems. Cox's hazard ratios of these parameters to mortality were not statistically significant in the any of the water systems.

CONCLUSIONS

Neither the years engaged in agriculture nor the number of pregnancies/deliveries influenced mortality in subjects living not only in the non-Jinzu River basin but also in the Jinzu River basin using a Cox's proportional hazards model.

Dramatic efficacy of cyclophosphamide pulsed therapy combined with double-filtration plasmapheresis for treating severe massive pulmonary hemorrhage associated with systemic lupus erythematosus

Abstract Pulmonary hemorrhage (PH) is a rare but fatal complication of systemic lupus erythematosus (SLE). We report a patient with SLE and a massive PH who was treated with double-filtration plasmapheresis synchronized with cyclophosphamide pulsed therapy. The patient showed dramatic improvement immediately and was followed for 3 years without recurrence. Prompt treatment during the acute phase of PH with this short-term intensive combination therapy may offer the best chance of success. There are few reports of long-term followup, especially in Japan.

Regeneration of defects in the articular cartilage in rabbit temporomandibular joints by bone morphogenetic protein-2

The purpose of this study was to investigate the therapeutic use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in internally deranged temporomandibular joints (TMJ). Defects (2 mm in diameter) were created in the surface of the condylar head. Lyophilized rhBMP-2 with collagen as the carrier was implanted in the defects in different doses: rhBMP-2 15 microg (n = 5); rhBMP-2 3 microg (n = 5); rhBMP-2 0.6 microg (n = 5). In the two control groups, the defects were either filled with collagen alone (n = 5) or left untreated (n = 5). Three weeks postoperatively the sites of defects were examined under light microscopy. In the 15 micromg and the 3 microg groups, new cartilage had filled the defects; endochondral ossification was also found deep within the defect. In the 0.6 microg group, fibrous tissue was proliferating in most areas of the defect, although cartilage was also found in some parts. In the two control groups, there was either soft tissue repair only or no evidence of tissue repair. These findings suggest that BMP-2 could stimulate the repair of defects in the articular cartilage of the mandibular condyle head during the 3 weeks postoperatively. To observe the progress of endochondral ossification in more detail, it may be necessary to extend the experiment for a longer period of time. However, this study supports the contention that BMP-2 may be useful in the regeneration of cartilage in TMJ disease.

Osteoinduction by recombinant human bone morphogenetic protein-2 in muscles of non-human primates

Heterotopic osteoinduction in a muscle of a medium-sized, non-human primate (Japanese macaque monkey; Macaca fuscata) was investigated with recombinant human bone morphogenetic protein-2 (rhBMP-2) mixed with atelopeptide type I collagen as the carrier. Nine monkeys were divided into three groups of three: groups I (1.25 mg rhBMP-2), II (250 micrograms rhBMP-2) and III (50 micrograms rhBMP-2). Four weeks after implanting into the calf muscle pouch, the implant was examined radiographically and histologically. In one specimen of three in group I, marked radio-opaque shadow, massive chondrogenesis and partial osteogenesis were observed. In the other two specimens, only microscopic calcification signs were recognized. In groups II and III, no findings of heterotopic osteoinduction were radiographically observed; however, nuclei from muscle bundles reacted to rhBMP-2 and were large and round, as in muscle bundles near the site of osteogenesis in group I. A positive control study using rats was carried out in parallel. This was a dose-finding study, with the monkeys in group III acting as a sub-effective dose (placebo) control, and rats acting as an active control, or verum, to show that the techniques are sufficiently sensitive. Bone morphogenetic protein appears to osteoinduce less bony material in soft tissue in primates than in rats.

Concurrent left-sided spontaneous pneumothorax in Japanese monogerminal twins

Monogerminal twin brothers aged 17 were admitted because of concurrent left-sided spontaneous pneumothorax. A familial background of this common disease in association with the human leukocyte antigen (HLA) has been suggested; however, the actual mode of inheritance in association with HLA typing is still uncertain. HLA analysis in this family revealed the HLA-A24, B61 (40), Cw3, DR4, DR53, and DQ3 haplotype in the twins and their father, who also had a medical history of spontaneous pneumothorax. We report these cases as an extremely rare example of familial occurrence of spontaneous pneumothorax.

An association between smoking habits and blood pressure in normotensive Japanese men

We conducted a cross-sectional study to clarify the dose-effect relationship of smoking habits with blood pressure in Japanese men. The subjects were 2781 normotensive male steelworkers ranging in age from 40 to 54 years. They were classified into five categories according to their smoking habits: non-smokers, ex-smokers, light smokers, moderate smokers and heavy smokers. Age, body mass index, salt intake, physical activity, drinking habits, and levels of gamma-glutamyl transpeptidase, total serum cholesterol, uric acid, creatinine and plasma glucose were analysed as covariates. The association between smoking habits and blood pressure was evaluated using analysis of covariance. Our results showed that there was no significant difference in the adjusted systolic and diastolic blood pressure between non-smokers and ex-smokers. The adjusted systolic and diastolic blood pressures in light, moderate and heavy smokers were significantly lower than in non- and ex-smokers. However, among smokers, no significant difference was observed in correlation with smoking amount. In conclusion, blood pressure of smokers was lower than that of non- and ex-smokers. However, there were no significant dose-effect relationships between smoking amount and blood pressure when lifestyle and other confounding factors were considered.

Association analysis of the pituitary adenyl cyclase activating peptide gene (PACAP) on chromosome 18p11 with schizophrenia and bipolar disorders

In neurons, pituitary adenyl cyclase activating peptide (PACAP) stimulates signaling cascades, involving cAMP and calcium. PACAP appears to play a role in up-regulation of tyrosine hydroxylase and dopamine beta-hydroxylase via protein kinase C and/or protein kinase A. Furthermore, the PACAP gene (ADCYAP1) is located in chromosome 18p11, where linkage of bipolar disorders and schizophrenia has been reported. In this study, we scanned the coding region of the PACAP gene for mutations in 24 Japanese patients with schizophrenia and 24 Japanese patients with bipolar disorders. No variant in the coding region was found. One polymorphism, INV3-37A/T, in the third intron was detected. Case-control comparisons revealed no significant association between this polymorphism and schizophrenia or bipolar disorders. This study did not provide evidence for the contribution of the PACAP gene to the etiology of schizophrenia or bipolar disorders in the Japanese population.

Chemotaxis of human CD4+ eosinophils

We reviewed the biological functions of CD4+ eosinophils, which are observed in peripheral blood, sputum and bronchoalveolar lavage fluid of various diseases. We have shown that CD4 molecules on human eosinophils are induced by tumor necrosis factor-alpha (TNF-alpha) stimulation. Interleukin-16 (IL-16) has been reported to bind a natural soluble ligand for the CD4 molecule. We reported that TNF-alpha-stimulated eosinophils migrate in a time- and dose-dependent manner against IL-16. Theophylline and dexamethasone significantly inhibited CD4 expression. Theophylline inhibited CD4+ eosinophil chemotaxis, but dexamethasone did not. Theophylline may prevent airway inflammation by downregulating the expression of CD4 molecule and CD4+ eosinophil migration. However, dexamethasone may inhibit airway inflammation through the downregulation of CD4 expression.

Dysregulation of IGF-I signaling in uterine leiomyoma

IGF-I expression has been observed in human uterine leiomyomas. To examine whether autocrine IGF-I signaling plays a role in the growth of these tumors, we used an animal model of uterine leiomyoma (the Eker rat) to investigate regulation of IGF-I and the IGF-I receptor (IGF-IR) expression in tumors and normal myometrium. During the normal estrous cycle, myometrial IGF-I expression peaked on the day of proestrus when the rate of proliferation in this tissue is greatest. In leiomyomas, the expression of IGF-I was increased 7.5-fold compared with the age-matched normal tissue. The level of IGF-IR mRNA in both tumor and non-tumor tissues was found to inversely correlate with that of IGF-I. Changes observed in IGF-I signaling components correlated with the activation state of the signal-transducing protein insulin receptor substrate-1 (IRS-1). During diestrus and proestrus when IGF-I levels were increasing, tyrosine phosphorylation of IRS-1 was increased up to 5.7-fold in the normal myometrium relative to estrus, when IGF-I levels were the lowest. Additionally, IRS-1 phosphorylation was 4-fold greater in leiomyomas relative to age-matched normal myometrium. Autocrine stimulation of the IGF-IR may, therefore, play a role in regulating the normal growth of the myometrium, and dysregulation of IGF-I signaling could contribute to the neoplastic growth of uterine leiomyomas.

The time course study of osteoinduction by bone morphogenetic protein-2 via adenoviral vector

We evaluated the time course of osteoinduction by an adenoviral vector, AxCAOBMP-2, in normal rats (Group I) and 2 immunosuppressed groups (Groups II and III). Immunosuppression was induced by 125 mg/kg of cyclophosphamide injected intraperitoneally the day before vector injection. Groups I and III received a high dose of AxCAOBMP-2 (25 microl; 8.75 x 10(8) pfu) and Group II a low dose (5 microl; 1.75 x 10(8) pfu). Each dose of AxCAOBMP-2 was injected into the right calf muscle of rats. On days 7, 14 and 21 postinjection, the osteoinducive activity in each group was investigated radiologically, histologically, immunohistochemically and biochemically. Osteoinduction was observed only in Groups II and III on days 14 and 21. The activity of osteoinduction in Group III was higher than that in Group II. There was little difference in the expression of LacZ between Groups I and III on day 3. However, there was a marked difference in BMP-2 protein expression between Groups I and III on day 7 postinjection. We speculated that the reason for this was that most of the infected cells were eliminated by the immune system of the host from days 3 to 7. These results suggest that gene therapy with AxCAOBMP-2 under transient immunosuppression may be useful for bone reconstruction.

Gene cloning and characterization of alanine racemases from Shigella dysenteriae, Shigella boydii, Shigella flexneri, and Shigella sonnei

Alanine racemase genes (alr) from Shigella dysenteriae, Shigella boydii, Shigella flexneri, and Shigella sonnei were cloned and expressed in Escherichia coli JM109. All genes encoded a polypeptide of 359 amino acids, and showed more than 99% sequence identities with each other. In particular, the S. dysenteriae alr was identical with the S. flexneri alr. Differences in the amino acid sequences between the four Shigella enzymes were only two residues: Gly138 in S. dysenteriae and S. flexneri (Glu138 in the other) and Ile225 in S. sonnei (Thr225 in the other). The S. boydii enzyme was identical with the E. coli K12 alr enzyme. Each Shigella alr enzyme purified to homogeneity has an apparent molecular mass about 43,000 by SDS-gel electrophoresis, and about 46,000 by gel filtration. However, all enzymes showed an apparent molecular mass about 60,000 by gel filtration in the presence of a substrate, 0.1 M l-alanine. These results suggest that the Shigella alr enzymes having an ordinary monomeric structure interact with other monomer in the presence of the substrate. The enzymes were almost identical in the enzymological properties, and showed lower catalytic activities (about 210 units/mg) than those of homodimeric alanine racemases reported.

Interleukin-4 is needed for the infection of monocytes by human cytomegalovirus

OBJECTIVE

We studied the ability of human cytomegalovirus (HCMV) to infect peripheral blood mononuclear cells (PBMC) pretreated with or without Th2-cytokine interleukin-4 (IL-4) in vitro.

METHODS

Adherent cells and nonadherent cells were obtained from PBMC. We inoculated these cells with HCMV at concentrations ranging from 0 to 10 ng/ml of IL-4. Immediate-early antigen-1 (IE-1) and glycoprotein H (gH) mRNAs were detected using the reverse-transcription polymerase chain reaction.

RESULTS

IE-1 and gH mRNAs could be detected in monocytes pretreated with IL-4. In contrast, no IE-1 mRNA was detected in monocytes pretreated without IL-4. We tested whether higher infectious titers could result in the infection of monocytes whether or not they were pretreated with IL-4. However, no IE-1 mRNA was detected in the monocytes not pretreated with IL-4. To elucidate how HCMV-infected monocytes affect lung tissue, human embryonic lung fibroblasts MRC-5 were cocultured with HCMV-infected monocytes. The cytopathic effects of HCMV were observed microscopically and was confirmed by direct immunoperoxidase staining with a human monoclonal antibody against the HCMV IE-1.

CONCLUSION

Our data strongly suggest that the ability of HCMV to infect monocytes may correlate with the presence of IL-4.

Visualization of IP(3) dynamics reveals a novel AMPA receptor-triggered IP(3) production pathway mediated by voltage-dependent Ca(2+) influx in Purkinje cells

IP(3) signaling in Purkinje cells is involved in the regulation of cell functions including LTD. We have used a GFP-tagged pleckstrin homology domain to visualize IP(3) dynamics in Purkinje cells. Surprisingly, IP(3) production was observed in response not only to mGluR activation, but also to AMPA receptor activation in Purkinje cells in culture. AMPA-induced IP(3) production was mediated by depolarization-induced Ca(2+) influx because it was mimicked by depolarization and was blocked by inhibition of the P-type Ca(2+) channel. Furthermore, trains of complex spikes, elicited by climbing fiber stimulation (1 Hz), induced IP(3) production in Purkinje cells in cerebellar slices. These results revealed a novel IP(3) signaling pathway in Purkinje cells that can be elicited by synaptic inputs from climbing fibers.

Relationship between exploratory eye movements and clinical course in schizophrenic patients

Exploratory eye movements are psychophysiological indicators of schizophrenia as well as smooth pursuit eye movements. To investigate whether these eye movements change in accordance with the clinical course of the condition in schizophrenia, exploratory eye movements (number of eye fixations, mean eye scanning length, responsive search score, evaluation of reproduced Fig. 1 and 2) of 28 schizophrenic patients were evaluated in repeat test design, conducted an average of 8 months apart. Subjects were first-medicated schizophrenics, half were outpatients and the remaining half were inpatients at the Neuropsychiatry ward of Tokyo Medical and Dental University Hospital. Exploratory eye movement patterns did not improve despite an improvement in clinical symptoms of schizophrenia. This result and those of previous studies of the exploratory eye movements of schizophrenic patients' families suggest that exploratory eye movements reflect a schizophrenic vulnerability marker. Furthermore, decreased mean eye scanning length (MESL) values were observed in subjects who showed unimproved symptoms, particularly negative symptoms over an extended period of time. The result suggests that a decrease in the MESL value may be the most sensitive indicator in the development of chronicity in schizophrenia.

[Detection of PSA mRNA in prostate cancer patients' blood]

A sensitive technique using reverse transcriptase-polymerase chain reaction (RT-PCR) for PSA mRNA has been used to detect circulating tumor cells in the peripheral blood of prostate cancer patients. We evaluated the clinical utility of this method for staging and monitoring for prostate cancer. The number of patients who were RT-PCR positive was increased in higher clinical stages. This technique may provide useful information for treating patients with prostate cancer, especially candidates for radical prostatectomy. Confirming the value of this modality as a prognostic factor will require further study.

2-Arachidonoylglycerol and anandamide oppositely modulate norepinephrine release from the rat heart sympathetic nerves

Anandamide (10(-7) and 10(-6) M) as well as a synthetic cannabinoid HU210 (10(-8) to 10(-6) M) suppressed the norepinephrine release evoked by perivascular nerve stimulation (PNS) of the rat heart Langendorff's preparation. The effects of HU210 and the lower dose of anandamide were completely blocked by the cannabinoid CB1-receptor antagonist AM251, while that of anandamide at 10(-6) M was partly mediated by arachidonate-derived metabolites. 2-Arachidonoylglycerol (2-AG), at 10(-6) M in the presence of DFP and indomethacin, increased PNS-evoked norepinephrine release, which was completely blocked by AM251. The present results suggest that the two endocannabinoids may oppositely participate in the CB1-receptor-mediated modulation of sympathetic norepinephrine release.

Infrared spectroscopic study on the properties of the anhydrous form II of trehalose. Implications for the functional mechanism of trehalose as a biostabilizer

FTIR spectra were obtained for several different states of trehalose including dihydrate crystal, anhydrous form II (designated by Gil, A. M.; Belton, P. S.; Felix V. Spectrochim. Acta 1996, A52, 1649-1659), anhydrate crystal, dried melt, amorphous solid and aqueous solution. From the observation of the symmetric and antisymmetric stretch vibrations of the glycosidic linkage, it is found that this sugar assumes at least three types of backbone conformations. Among them, the conformation with C(2) symmetry is characterized as 'open state', which means that the sugar easily absorbs water molecules. The conformation of the sugars in anhydrous form II and in freeze-dried trehalose is shown to be in the open state. Next, the hygroscopic properties of the anhydrate, form II and the amorphous solid are compared based on their IR spectra. Interestingly, form II alone is converted to the original dihydrate in a week under mild environmental-like conditions: relative humidity of 40% and room temperature. These results suggest the possibility that form II plays a role in avoiding the devitrification of the sugar glass. Finally, we discuss the role of form II in preserving freeze-dried biomaterials.

Overexpression of homeobox gene HOXD3 induces coordinate expression of metastasis-related genes in human lung cancer cells

Homeobox-containing genes are expressed in spatiotemporal fashion during embryogenesis and act as master transcription-regulating factors which control the expression of a variety of genes involved in morphogenesis. They are also expressed in a tissue-specific manner in normal adult tissues and appear to give cells spatial information in the maintenance of their architectural integrity. We transfected a HOXD3 class I homeobox-containing gene into human lung cancer A549 cells and investigated alterations in gene expressions and phenotypes related to the maintenance of tissue architecture in HOXD3-overexpressing A549 cells. In the HOXD3-overexpressing cell lines, expression of E-cadherin was lost and plakoglobin was strongly repressed, whereas integrin alpha3 and beta3 were up-regulated and N-cadherin and integrin alpha4 were newly expressed. Compared with parental and control transfectant lines, the HOXD3-overexpressing cell lines showed highly motile and invasive activity. Blocking experiments using anti-integrin beta1 and beta3 suggested that the increased haptotaxis of the HOXD3-overexpressing cells to vitronectin resulted from increased expression and activation of integrin alphavbeta3, and that overexpression of the HOXD3 gene converted the integrin beta1-dependent haptotaxis to fibronectin into both integrin beta1- and beta3-dependent one. HOXD3 overexpression increased production of matrix-degrative enzymes including matrix metalloproteinase-2 and urokinase-plasminogen activator. When the tumor cells were intravenously injected into the tail veins of nude mice, HOXD3 transfectants formed a significantly large number of metastatic foci in lungs compared with the control transfectants. These findings suggest that HOXD3 can act as a metastasis-promoting gene in human lung cancer A549 cells.

Contribution of CD54 to human eosinophil and neutrophil superoxide production

We have reported that CD54 on eosinophils is involved in eosinophil degranulation. However, the role of CD54 in eosinophil and neutrophil superoxide production is still uncertain. We assessed the effect of CD54 on eosinophils and neutrophils in recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF)- or phorbol myristate acetate (PMA)-induced superoxide production through CD18. Anti-CD54 monoclonal antibody attenuated leukocyte aggregation and superoxide production of rGM-CSF- or PMA-stimulated neutrophils and PMA-stimulated eosinophils. Anti-CD18 monoclonal antibody or theophylline attenuated superoxide production of eosinophils and neutrophils stimulated by either stimuli. Flow cytometric analysis demonstrated CD54 expression on freshly isolated neutrophils but not on freshly isolated eosinophils. CD54 newly expressed on eosinophils reached its peak expression 30 min after PMA stimulation. The increase in CD18 and CD54 expression on neutrophils caused by rGM-CSF stimulation was partially inhibited by theophylline. These data demonstrated that CD54 and CD18 interaction of eosinophils or neutrophils is involved in superoxide production and that the inhibition of superoxide production by theophylline may be at least partly due to the inhibition of CD54 and CD18.

7Li 2D CSI of human brain on a clinical scanner

Lithium salts have been widely used in the treatment of mood disorders, but the mechanism of action is still not clear. In this work, a methodology for two-dimensional Lithium-7 imaging on clinical systems is presented. The data were acquired using a phosphorus volume head coil that was re-tuned for the Lithium-7 frequency. A spectroscopic sequence was used to acquire the free induction decay (FID) after volume excitation using a hard pulse. The results obtained on the head of patients undergoing lithium treatment (n = 7, 0.6 mEq/l average serum level) demonstrate that images of adequate signal to noise ratio (100:1) can be obtained in acceptable imaging times (55 min) using the proposed methodology. The distribution of 7Li appears uniform in the brains of the patients studied.

Theophylline inhibits TNF-alpha-induced CD4 expression on human eosinophils and CD4+ eosinophil migration

BACKGROUND

Increasing evidence regarding asthma suggests that CD4+ cells are preferentially recruited to sites of bronchial inflammation. Interleukin (IL)-16 has been reported as playing an important role in the accumulation of CD4+ cells. We have shown that the CD4 molecule is expressed on normal human eosinophils by tumor necrosis factor (TNF)-alpha stimulation.

METHODS

We evaluated the effects of theophylline, KF19514 [a selective phosphodiesterase (PDE) IV inhibitor] and dexamethasone on CD4 expression on eosinophils and eosinophil migration in response to IL-16, a natural soluble ligand of the CD4 molecule.

RESULTS

The maximum eosinophil migration was observed when eosinophils were cultured with TNF-alpha at 10 ng/ml for 18 h and the concentration of IL-16 was 10 pg/ml. CD4+ eosinophil migration in response to IL-16 was mostly, if not fully, chemokinetic and this migration was significantly inhibited by Fab of anti-CD4 monoclonal antibody. Theophylline (10(-4)-10(-3) M), KF19514 (10(-7)-10(-6) M) and dexamethasone (10(-8)- 10(-6) M) significantly inhibited CD4 expression on eosinophils induced by TNF-alpha. Theophylline (10(-3) M) and KF19514 (10(-6) M) inhibited CD4+ eosinophil migratory responses induced by IL-16, but 10(-6) M dexamethasone did not. Theophylline and KF19514 augmented the intracellular adenosine-3',5'-cyclic monophosphate (cAMP) concentration in eosinophils, suggesting modulation by cAMP of CD4 expression and eosinophil migration.

CONCLUSIONS

These data suggest that TNF-alpha-induced CD4+ eosinophils may contribute to eosinophil migratory responses induced by IL-16. Theophylline and selective PDE IV inhibitor may prevent airway inflammation by downregulating CD4 expression on eosinophils and inhibiting eosinophil migration through CD4 and IL-16 interaction.

Mechanism of hypergammaglobulinemia by HIV infection: circulating memory B-cell reduction with plasmacytosis

The mechanism of hypergammaglobulinemia in patients infected with HIV has remained unclear in spite of the identification of a reduction of CD4+ T cells. The amounts of CD27+ memory B cells were remarkably reduced in the peripheral blood and immunoglobulin (Ig) production was diminished in HIV-infected patients. Some of the freshly isolated patients' T cells expressed the CD70 (CD27 ligand) on the surface and the CD70 expression on both of the CD4+ and CD8+ T cells was greatly enhanced by various stimuli. It was also striking that plasmacytosis was observed in patients' bone marrow. Thus, our findings suggest that CD70 expressed spontaneously or by activation on T cells of HIV-infected patients stimulates memory B cells via CD27 and promotes their differentiation into plasma cells, resulting in the elevation of serum Ig levels and the elimination of circulating memory B cells in HIV-infected patients.

Age-related reduction of extrastriatal dopamine D2 receptor measured by PET

Although the aging effect of dopamine D2 receptor in the striatum is well-documented, the effect of age on the extrastriatal dopamine D2 receptor has not been fully examined. Since the density of extrastriatal dopamine D2 receptor is very low, suitable ligands are limited. In this study, we used [11C]FLB 457 to quantify the extrastriatal dopamine D2 receptor in the living human brain. Twenty-seven healthy male subjects aged from 21 to 82 years participated in the positron emission tomography study. Extrastriatal [11C]FLB 457 binding was quantified with a reference tissue model using cerebellum as a reference region. Binding potentials corresponding to Bmax/Kd were used to evaluate age-related change. We found age-related decreases of D2 receptor binding in all measured extrastriatal regions. The decrease of D2 receptor binding was 13.8% per decade in frontal cortex, 12.0% in temporal cortex, 13.4% in parietal cortex, 12.4% in occipital cortex, 12.2% in hippocampus, and 4.8% in thalamus. These findings suggest that the amounts of D2 receptor declines in all brain regions as part of the normal aging process.