Chymase is activated in the hamster heart following ventricular fibrosis during the chronic stage of hypertension

Chronic pressure overload induces cardiac tissue remodeling. Chymase is known to regulate matrix metabolism and angiotensin II formation. In the present study, we investigated the pathophysiological functions of chymase in the pressure-overloaded hamster heart induced by a two-kidney, one-clip (2K1C) hypertension procedure. Fibrosis and apoptosis were observed in the pressure-overloaded hearts of 2K1C hamsters 32 weeks after clipping, but these histological changes were not detected at 16 weeks. Heart chymase-like activity of 2K1C hamsters at 32 weeks increased 5.2-fold compared with that at 16 weeks, while angiotensin-converting enzyme was not activated. Chymase might be involved in cardiac tissue remodeling during the chronic stage of hypertension.

SPECT imaging of normal subjects with technetium-99m-HMPAO and technetium-99m-ECD

Technetium-99m-HMPAO and 99mTc-ECD have been used for regional cerebral blood flow (rCBF) studies using SPECT. However, details of the normal perfusion patterns of these agents still remain to be clarified. HMPAO-SPECT and ECD-SPECT images of normal individuals were investigated using an anatomical standardization technique.

METHODS

Twenty healthy subjects participated in this study. In 10 of these, regional cerebral perfusion was measured with HMPAO, and in the other 10, ECD was used. All SPECT images were globally normalized to 50 counts/voxel, and then, each SPECT image was transformed into a standard brain anatomy format with the aid of x-ray CT of each subject and a computerized human brain atlas system (HBA). Mean and s.d. images for each tracer were calculated on a voxel-by-voxel basis. For comparison of these SPECT images with blood flow, rCBF images were generated using PET in a separate group of 10 healthy male subjects during an eyes-closed resting state. The PET images were globally normalized to 50 ml/100 g/min and anatomically standardized using each subject's MRI and the HBA for the SPECT images.

RESULTS

In the HMPAO-SPECT images, relatively high radioactivities Were observed in the basal ganglia and cerebellum. In the ECD-SPECT images, high levels were observed in the medial aspect of the occipital lobe. These regions with high radioactivity were not apparent in the rCBF-PET images.

CONCLUSION

While both HMPAO and ECD have been used to investigate rCBF, their perfusion patterns differ from rCBF-PET images. This presumably reflects differences in the mechanism of accumulation of each agent in the brain. For clinical diagnoses, these patterns must be taken into consideration.

High-density lipoproteins from probucol-treated patients have increased capacity to promote cholesterol efflux from mouse peritoneal macrophages loaded with acetylated low-density lipoproteins

To elucidate the anti-atherogenic effect of probucol, high-density lipoprotein (HDL) was isolated from probucol-treated patients (n = 14) and compared with that from control subjects (n = 12). The HDL obtained from probucol-treated patients was low in cholesteryl ester (CE) in comparison with that from control subjects (21.3 +/- 3.9 mol per cent vs. 27.6 +/- 3.2 mol% of total lipids. P < 0.001), and the peak diameters of patients' HDL were significantly smaller than those of control subjects on 4-30% non-denaturing polyacrylamide gradient gel electrophoresis (10.6 +/- 0.6 nm vs. 12.1 +/- 0.4 nm, P < 0.001). These data may be explained by the increased cholesteryl ester transfer protein (CETP) activities of probucol-treated patients (129 +/- 12% of control subjects, P < 0.001). The in vitro ability of HDL to remove CE from lipid-laden macrophages induced by incubation with acetylated low-density lipoprotein (Ac-LDL) was studied. The small and CE-poor HDL obtained from probucol-treated patients had a greater capacity to promote CE efflux from macrophages than did control HDL (59.8 +/- 6.9% vs. 44.2 +/- 5.4%, P < 0.01). Furthermore, the ability of HDL to promote cholesterol efflux correlated negatively with the CE content and particle diameter of HDL (r = -0.561 and r = -0.583 respectively; P < 0.01). When the inhibitory effect of HDL on the incorporation of [14C]-oleate into cellular cholesteryl ester was compared, the HDL from patients and control subjects inhibited CE formation to a similar extent. The enhanced ability of probucol-treated patients' HDL may, therefore, be involved in the acceleration of hydrolysis of the CE pool in macrophages. Taken together, we conclude that CETP plays a crucial role in making HDL more active in its anti-atherogenic function by reducing CE and making HDL smaller, and that probucol may enhance reverse cholesterol transport by activating CE transfer in vivo. The current study demonstrated, for the first time, that HDL modified by enhanced CETP activity in vivo is potentially anti-atherogenic.

The influence of peri-operative blood transfusion during radical hysterectomy on the prognosis of uterine cervical cancer

To evaluate the clinical implications of peri-operative transfusion in the surgical treatment of uterine cervical cancer, a detailed analysis of the cumulative survival rate was performed using clinical data from 145 patients with FIGO stage Ib cervical cancer of the squamous cell type acquired between 1982 and 1989 at the Center for Adult Diseases. The cumulative survival rate was statistically analyzed using the Kaplan Meier method. Of the 145 patients with stage Ib cancer, 103 were considered to have undergone complete excision and received no further treatment post-operatively, and 42 were considered to have undergone incomplete excision because of the involvement of lymph nodes or the lymphovascular space. Of the 79 patients in the former group who received peri-operative transfusion, 69 received less than seven units (1400 mL) and 10 received more than eight units (1600 mL). The cumulative 5-year survival rate was 100% in the 24 patients who received no transfusions, 91.7% in those who received less than 1400 mL, and 90.0% in those who received more than 1600 mL. Similarly, of the 42 patients in the incomplete excision group, nine did not receive any peri-operative transfusion, 27 received less than 1400 mL, and six received more than 1600 mL. The 5-year survival rate in these groups was 88.9, 77.8 and 50.0%, respectively. The survival rate of our patients with stage Ib cervical cancer without peri-operative transfusion was significantly higher than that of those with transfusion, regardless of post-operative irradiation therapy status, indicating that peri-operative transfusion has an adverse influence on the prognosis in cervical cancer.

Biparental alleles of HLA-G are co-dominantly expressed in the placenta

HLA-G is the only major histocompatibility complex molecule expressed in the human placenta and thus has been considered to be necessary for maintenance of pregnancy. We investigated whether HLA-G expression is regulated in a parent-of-origin allele-specific manner. Of six first trimester and three third trimester placentas, three first trimester and two third trimester placentas showed heterozygosity at the PstI polymorphic site in the 3'-untraslated region. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed biallelic expression of HLA-G in all the informative cases, indicating that HLA-G is not imprinted during the gestational period, at least at the transcriptional level. As HLA-G has been postulated to be polymorphic not only at the DNA sequence level but also at the peptide level, co-dominant expression of the gene suggests that each parental allele is involved in the allogenic response during pregnancy.

Spool-like stent for the open sternum after cardiac operations

Severe edematous heart after a cardiac operation is impossible to treat if there is compression of the heart due to the sternum. In these patients delayed sternal closure may be a useful procedure until the heart decreases in size. We devised a spool-like stent for the open sternum to maintain the optimal cardiac space for the severely edematous heart and to fix the chest wall to allow for management while the sternum is open.

The novel role of 3',5'-guanosine monophosphate (cGMP) on the differentiation of trophoblasts: comparison with the effects of 3',5'-adenosine monophosphate (cAMP)

We investigated the effects of 3',5'-guanosine monophosphate (cGMP) on the differentiation of human trophoblasts. Isolated cytotrophoblasts were cultured with 8-bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP) or 8-bromoadenosine 3'5-cyclic monophosphate (8-Br-cAMP) and then stained immunocytochemically with anti-human chorionic gonadotropin (anti-hCG) antibody to identify hCG expression as an index of differentiation. Concurrently, morphological changes from cytotrophoblasts to syncytiotrophoblasts were analyzed. Both 8-Br-cGMP and 8-Br-cAMP enhanced the expression of hCG in cultured cytotrophoblasts with the differentiation of cytotrophoblasts to syncytiotrophoblasts dose-dependently. With regard to trophoblast proliferation, 8-Br-cAMP but not 8-Br-cGMP enhanced [3H]thymidine uptake by these cells. hCG, a trophoblast-specific glycoprotein hormone has been identified as a potent growth factor for trophoblasts, also increased [3H]thymidine uptake and the intracellular 3',5'-adenosine monophosphate (cAMP) concentration. However, in this study, hCG did not increase the concentration of intracellular cGMP. We also showed that sodium nitroprusside (SNP), which is a donor of nitric oxide (NO), enhanced intracellular cGMP concentration. These results suggest that cGMP enhances trophoblast differentiation without affecting their proliferation, while cAMP enhances both differentiation and proliferation. We conclude that an alternative pathway mediated through cGMP is responsible for the differentiation of trophoblasts. NO may be involved in trophoblast differentiation with an increase in cellular cGMP level.

[Development of a new statistical evaluation method for brain SPECT images]

The purpose of this study was to develop a new statistical evaluation method for Brain SPECT images. First, we made normal brain image databases using 99mTc-ECD and SPECT in 10 normal subjects as described previously. Each SPECT images were globally normalized and anatomically standardized to the standard brain shape using Human Brain Atlas (HBA) of Roland et al. and each subject's X-CT. Then, mean and SD images were calculated voxel by voxel. For the next step, 99mTc-ECD SPECT images of a patient were obtained, and global normalizing and anatomical standardization were performed as the same way. Then, a statistical map was calculated as following voxel by voxel; (P-Mean)/SD x 10 + 50, where P, Mean and SD indicate voxel value of patient, mean and SD images of normal databases, respectively. We found this statistical map was helpful for clinical diagnosis of brain SPECT studies.

Postural control under clinorotation in upside-down catfish, Synodontis nigriventris

The upside-down catfish Synodontis nigriventris has a unique habit of swimming and resting upside-down in free water. This behavior leads to the assumption that the catfish has a specific gravity information processing system. We examined the postural control behaviors in the catfish under clinorotation which is usually used for producing pseudo-microgravity. Synodontis nigriventris kept its body posture at a stable area of the rotated flask in which the catfish was kept, when it was clinorotated at the rate of 60 rpm. In contrast to Synodontis nigriventris, a related species, Corydoras paleatus, did not show such steady postural control. When the flask was rotated at a lower rate of 30 rpm or a higher rate of 100 rpm, Synodontis nigriventris as well as Corydoras paleatus showed a considerable disturbed control of body posture. In this condition, they were frequently rotated with the flask. These findings suggest that Synodontis nigriventris has a high ability to keep upside-down posture and the gravity sensation in this catfish is likely to contribute to its different postural control from that of many other fishes.

Deficiency of plasma platelet-activating factor acetylhydrolase: roles of blood cells

Platelet-activating factor (PAF), a potent mediator of inflammation and circulatory shock, is inactivated by the enzyme PAF acetylhydrolase. Plasma PAF acetylhydrolase deficiency occurs even in healthy subjects. We hypothesized that erythrocyte PAF acetylhydrolase could play a supplementary role in this plasma acetylhydrolase deficiency. We examined 1,030 subjects who participated in mass checkups, and assayed plasma and erythrocyte PAF acetylhydrolase. We also investigated the degradation of exogenous PAF by erythrocytes or other blood cells obtained from subjects who exhibited the plasma enzyme deficiency. The incidence of the plasma enzyme deficiency in this general Japanese population was 4.7% (48/1,030). None of the subjects with the deficiency had a history of allergy, circulatory shock, or chronic inflammatory diseases. The mean values for erythrocyte cytosolic PAF acetylhydrolase activity in the normal and deficient subjects were 0.51 +/- 0.15 (SD) and 0.71 +/- 0.28 nkat (nmol/s)/g protein, respectively, and the difference was significant (P < 0.001, Mann-Whitney U-test). The half-life of 10 nmol/l [3H]PAF in plasma from normal subjects was about 5 min, and the half-life in whole blood or erythrocyte suspension in autologous plasma was almost the same as that in plasma. In plasma from deficient subjects, unchanged PAF virtually remained and the degradation in whole blood or erythrocyte suspension was a little faster than in plasma. We conclude that erythrocytes contribute only little to PAF metabolism in normal blood but they account for almost all of the slow PAF degradation in blood from subjects deficient in plasma PAF acetylhydrolase.

High-affinity calcium-binding site in the gama-carboxyglutamic acid domain of bovine factor VII

The calcium-mediated interaction of factor VIIa with tissue factor is considered to be the primary trigger of blood coagulation. To determine the role of calcium ions in the action of factor VII, we prepared monoclonal antibodies whose binding to factor VII was calcium-dependent. A monoclonal antibody designated C6 strongly inhibited factor VII-induced clotting at a molar ratio of factor VII to antibody of 1:1. The half-maximal binding of factor VII to the C6 antibody was observed at a concentration of calcium ions of 80 microM. Proteolytic fragments of factor VII were assayed for their ability to inhibit competitively the binding of 125I-factor VII to immobilized C6 antibody. The binding was inhibited by increasing amounts of factor VII, by a fragment that contained the gamma-carboxyglutamic acid (Gla) domain linked to first epidermal growth factor-like domain, and by a Gla domain peptide (residues 1-41), over a range of concentration of 10(-9) to 10(-7) M. The antigenic site recognized by the monoclonal antibody C6, which was generated upon the high-affinity binding of calcium ions, was located in the Gla domain. The C6 antibody inhibited the activation of factor X and the amidolytic activity of factor VIIa in the presence of tissue factor. These results demonstrate that a high-affinity calcium-binding site(s) is located in the Gla domain of factor VII, which is concerned with the initiation of tissue factor-mediated blood coagulation by factor VIIa.

Surface coverage of vascular grafts with cultured human endothelial cells from subcutaneous fat tissue obtained with a biopsy needle

Surface coverage with autogeneous endothelial cells is effective in reducing thrombogenicity of an artificial vascular graft, but procedure for obtaining the cells is invasive for patients. The purpose of this study was to establish cultures of human endothelial cells separated from a small piece of subcutaneous fat tissue. A piece of tissue weighing about 10 mg was obtained from subcutaneous fat using a biopsy needle, and treated with collagenase and dispase. Microvascular endothelial cells were selected and other types of cells contaminating the cultures were eliminated by scraping with a needle under a microscope. The yield of the cells was 8362 +/- 4264/10 mg of subcutaneous fat (n = 7). The cultures reached confluence in about 2 weeks. The cells were positive for von Willebrand factor, P-selectin, and uptake of acetylated low density lipoprotein. The cells produced 15.9 +/- 3.3 ng/mg cell protein/h of 6-ketoprostaglandin F1 alpha (n = 5) when stimulated with thrombin. Thrombin also stimulated the production of platelet-activating factor: 7653 +/- 4297 dpm/10(6) cells (n = 5). Endothelin-1 accumulation in the medium of unstimulated endothelial cells was 0.54 +/- 0.16 ng/mg cell protein/10 h (n = 8). As a preliminary experiment for graft seeding, the cells were also cultured on pieces of a gelatin-coated Dacron graft, and scanning electron microscopy revealed the surface coverage of the graft. We herein described about successful culture of human microvascular endothelial cells from subcutaneous fat tissue obtained using a biopsy needle. The cultured cells may be applicable to a seeded vascular graft.

Intraoperative implantation of percutaneous left ventricular assist system

The percutaneous left ventricular assist system, using modified Dennis technique, has been used successfully to treat patients experiencing severe cardiogenic shock in a variety of nonsurgical situations. Fluoroscopy is generally essential for implantation. Our experience with the implantation of the percutaneous left ventricular assist system during operations is described here. The percutaneous left ventricular assist system was applied using transesophageal echocardiographic imaging and by leading with the index finger through the right atrium without fluoroscopy.

Signal transduction through mu kappa B-cell receptors expressed on pre-B cells is different from that through B-cell receptors on mature B cells

We introduced kappa light chain genes into pre-B cells to increase the surface mu HC expression, and established transfectants expressing mature type of B-cell receptors (BCR) on pre-B-cell surfaces. Since the cytoplasmic conformations of the reconstituted BCR and intrinsic pre-B-cell receptor (pre-BCR) are identical, they would be connected with the identical signal transduction pathways in pre-B cells. By using the transfectants, we revealed that the reconstituted BCR on pre-B cells was functionally equivalent to BCR on mature B cells in terms of the induction of intracellular Ca++ mobilization. However, we found that the signal-transduction pathways through BCR on pre-B cells were quantitatively different from those mature B cells in two ways. First, cross-linkage of the reconstituted BCR on pre-B cells induced preferential tyrosine phosphorylation of p120 and p100, which was not observed when BCR on mature B cells was cross-linked. Second, BCR in pre-B cells was physically associated with a larger amount of phosphatidylinositol-3 kinase (PI-3K) than BCR in mature B cells in spite of the fact that both pre-B and B cells expressed a similar amount of PI-3K in cytoplasm. Signals through pre-BCR and BCR are known to cause distinct biological effects in B-cell development. The biochemical features in the downstream of reconstituted BCR on pre-B cells, which we revealed in this study, will be of help in understanding the mechanism of functional differences between pre-BCR and BCR.

P53 protein expression in pancreatic tumors and its relationship to clinicopathological factors and prognosis

We examined the expression of p53 protein by immunohistochemical method in a series of pancreatic tumors and evaluated its relationships to the clinicopathological factors and prognosis. The study involved 108 cases of pancreatic tumors (79 ductal carcinomas, 1 acinar cell carcinoma, 14 endocrine tumors, 6 solid cystic tumors, 8 benign ductal tumors) and 8 chronic pancreatitides. Thirty-nine cases of pancreatic ductal carcinoma (49.4%) were positive for p53 protein. Analysis of the Cox hazards model identified p53 positivity and stage at the initial operation as an independent prognostic factor. Patients with p53 positive ductal carcinomas had a greater risk of death compared to p53 negative cases (P < 0.05). There was, however, no statistically significant correlation between p53 protein expression and other clinicopathological factors. Cases of stage III and IVb with positive p53 showed a bleak prognosis compared to p53 negative cases (P < 0.05). Our results suggest that p53 expression is common in invasive pancreatic ductal carcinomas and may have a prognostic value.

Functional anatomy of GO/NO-GO discrimination and response selection--a PET study in man

The purpose of this study was to identify the functional fields activated in relation to the NO-GO decision. Nine healthy subjects participated in the study which consisted of two test positron emission tomography (PET) scans (GO/NO-GO task and response selection task) and one control scan. In the response selection task, subjects were asked to flex their thumb of the right hand when a light emitting diode (LED) placed 60 cm from their eyes turned on red and to flex their index finger of the right hand when LED turned on green. In the GO/NO-GO task, subjects were asked to flex their thumb when the LED turned on red, however, they were asked not to move their fingers when LED turned on green. In the control state, they were asked simply to look at the LED without any movement of finger during the course of the scan. The mean regional cerebral blood flow (rCBF) change images for each task minus control and task minus task were calculated and fields of significant rCBF changes were identified. Several fields in the prefrontal cortex of the right hemisphere were specifically activated in relation to the GO/NO-GO task. The results indicate that the prefrontal cortex of the right hemisphere may be a key structure to make a decision not to move.

A simple method for the quantification of benzodiazepine receptors using iodine-123 iomazenil and single-photon emission tomography

Iodine-123 iomazenil (Iomazenil) is a ligand for central type benzodiazepine receptors that is suitable for single-photon emission tomography (SPET). The purpose of this study was to develop a simple method for the quantification of its binding potential (BP). The method is based on a two-compartment model (K1, influx rate constant; k2', efflux rate constant; VT' (=K1/k2'), the total distribution volumes relative to the total arterial tracer concentration), and requires two SPET scans and one blood sampling. For a given input function, the radioactivity ratio of the early to delayed scans can be considered to tabulate as a function of k2', and a table look-up procedure provides the corresponding k2' value, from which K1 and VT' values are then calculated. The arterial input function is obtained by calibration of the standard input function by the single blood sampling. SPET studies were performed on 14 patients with cerebrovascular diseases, dementia or brain tumours (mean age+/-SD, 56.0+/-12.2). None of the patients had any heart, renal or liver disease. A dynamic SPET scan was performed following intravenous bolus injection of Iomazenil. A static SPET scan was performed at 180 min after injection. Frequent blood sampling from the brachial artery was performed on all subjects for determination of the arterial input function. Two-compartment model analysis was validated for calculation of the VT' value of Iomazenil. Good correlations were observed between VT' values calculated by three-compartment model analysis and those calculated by the present method, in which the scan time combinations (early scan/delayed scan) used were 15/180 min, 30/180 min or 45/180 min (all combinations: r=0.92), supporting the validity of this method. The present method is simple and applicable for clinical use.

Suppression of humoral immunity by monoclonal antibody to CD79b, an invariant component of antigen receptors on B lymphocytes

CD79b is an invariant component of antigen receptors on B lymphocytes. Previous data have suggested that monoclonal antibody (mAb) to CD79b would introduce negative signals into B lymphocytes and suppress humoral immunity. We tested this hypothesis in this study using in vitro assay systems, and revealed that anti-CD79b mAb effectively suppressed the antibody response to a T-cell dependent antigen. The speculated mechanisms for this immunosuppression were: (i) down-modulation of antigen receptors, (ii) inhibition of B lymphocyte differentiation, and (iii) induction of B lymphocyte unresponsiveness. Of these three, we confirmed that the first two were actually induced by anti-CD79b mAb treatment, whereas the in vitro system could not induce the unresponsiveness of B lymphocytes.

[Regional distribution of the muscarinic cholinergic receptor in the human brain studied with 11C-benztropine and PET using an anatomical standardization technique]

We measured regional distribution of the muscarinic cholinergic receptor in the normal human brain with 11C-benztropine (BZT) and positron emission tomography (PET) using an anatomical standardization technique. Seven normal volunteers who gave informed consents were involved in this study. Immediately after intravenous injection of 11C-BZT into the subjects, we started dynamic PET scanning and serial frequent arterial blood sampling. Analyses of plasma metabolites were also performed at selected time points and plasma time activity curves (TAC) of unmetabolized ligand were generated. From these PET and TAC data, we obtained Patlak plot slope calculation images. Using the HBA (human brain atlas) system, the Patlak plot slope calculation image of each subject was transformed into the shape of the standard brain. Mean and standard deviation (SD) calculation images were generated from those anatomically standardized images. On these mean and SD images, we placed regions of interest which were previously outlined on a MR image of the standard brain. From those data, we found the highest receptor distribution in the striatum and occipital cortex, as well as high distribution in the frontal, parietal, and temporal cortices, which were consistent with previous reports. These results suggested that anatomical standardization of PET receptor images with 11C-BZT will be useful for delineating the physiological or pathological alterations of the muscarinic cholinergic receptor in the human brain.

Topographic representation in human intraparietal sulcus of reaching and saccade

Regional cerebral blood flow was measured by positron emission tomography in seven subjects during reaching with saccade, reaching without saccade, saccade and control tasks. The reaching with saccade task activated two spatially distinct areas in the contralateral intraparietal sulcus (IPS) compared with the control condition. The area located in the anterior part of the IPS was also activated during the reaching without saccade but not during the saccade task. The other area, located in the posterior part of the IPS was, in contrast, active during the saccade but not the reaching without saccade task. The results indicate that the human IPS is functionally heterogeneous, and that functional roles of its anterior and posterior parts include control of reaching movements and eye movements, respectively.

Assessment of a Continuing Education Evaluation Framework

This study analyzes a systems model for evaluation research of continuing education (CE) and reports on the result of a quasi-experimental study of a stoma care CE program. Holzemer's conceptual framework for evaluating CE consisting of the learner, setting, and program along with a systems model was used as an organizing framework. A quasi-experimental design (n = 24 experimental group and n = 27 control group) was used to evaluate the impact of the CE program. Pre- and post-tests of participants' knowledge and skills of stoma care were evaluated. Participants' satisfaction with the course was surveyed by questionnaire during the course, on completion and four months after the course. No significant differences were found between the two groups. The revised framework included the concept of needs assessment and the impact of the CE program on patient care.

Changes in regional cerebral blood flow during self-paced arm and finger movements. A PET study

The purpose of this study was to identify the functional fields activated in relation to the self-paced proximal and distal arm movements. The regional cerebral blood flow (rCBF) was measured with positron emission tomography (PET) and 15O-labelled H2O (H2(15)O) in eight healthy subjects. All subjects performed the following three tasks: (1) repetitive opposition of thumb and index finger of the right hand, (2) repetitive co-contraction of biceps and tricepts brachii muscles of the right arm, and (3) rest. The mean rCBF change images for each task minus control was calculated and fields of significant rCBF changes were identified. Each movement activated different fields in the primary motor area (MI), the dorsal aspect of the premotor area (PMA) and the superior part of the prefrontal area (PFA) of the contralateral hemisphere. In these areas, arm fields were located relatively dorsally to the finger fields. In addition, specific fields in the ventral part of the PMA, the supplementary motor area (SMA), the superior parietal lobule (SPL) of the contralateral hemisphere, and the ipsilateral PFA were consistently activated during both movements. Due to a limited a field of view of the PET scanner in the axial direction, the PET scan could not cover the cerebellum. The results indicate that there may be somatotopical organization not only in the MI but also in the dorsal part of the PMA and the PFA, and that the specific fields in the ventral part of the PMA, the SMA, the SPL, and the PFA may be involved in self-paced movement.