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.

Internal thoracic artery holder for coronary artery bypass grafting

An arterial graft holder was designed to facilitate coronary artery bypass grafting using arterial conduits. It is possible to open the heel of the arterial conduit and stitch the most difficult angle of the anastomosis under optimal visualization. This internal thoracic artery holder is atraumatic and protects the arterial conduit wall from crush injuries caused by vascular forceps. Anastomosis without the endothelial injury may provide long-term patency of the coronary artery bypass graft.

Hypoperfusion in the limbic system and prefrontal cortex in depression: SPECT with anatomic standardization technique

Depression is a common psychiatric illness, and several reports have described cerebral blood flow (CBF) abnormalities on SPECT studies in affected patients. However, because region of interest analyses were used to determine significant CBF changes in these studies, there were methodological limitations. Therefore, we investigated CBF distribution abnormalities in depression on a pixel-by-pixel basis using SPECT and an anatomic standardization technique that has been commonly used for PET activation studies.

METHODS

Eleven patients with unipolar depression, six patients with bipolar depression and nine age-matched normal control subjects underwent HMPAO brain SPECT studies. The radioactivities of SPECT images for each subject were globally normalized to 100 counts/pixel. Then, each SPECT image was transformed for standard brain anatomy using a computerized Human Brain Atlas system. For each group, the mean and variance images were calculated from the standardized anatomic SPECT images, and group comparisons were performed on a pixel-by-pixel basis.

RESULTS

Significant decreases in CBF in the prefrontal cortices, limbic systems and paralimbic areas were observed in both depression groups compared with the normal control group.

CONCLUSION

Decreases in CBF in these regions may be related to impaired attention as well as cognitive and emotional responses, which have been recognized as usual symptoms in depression. The anatomic standardization technique promises to be useful for group comparison analysis of brain SPECT on a pixel-by-pixel basis for individual neurological and psychiatric diseases.

[Relation among lifestyle, social network, blood pressure and serum lipids in the elderly]

The relationships among seven lifestyle factors including stress, which is focused on as a risk factor for cardiovascular disease recently, social network, blood pressure and serum lipids in the elderly were examined in a cross sectional study of 85 males and 65 females aged 60 years or over in the city of Sayama, Saitama Prefecture. The seven lifestyle factors were as follows: (1) amount of alcohol consumption, (2) cigarette smoking, (3) Physical exercise, (4) sleeping time per night, (5) nutritional balance, (6) body weight, and (7) stress. As social network factors, marital status and coping factor for stress and/or anxiety were introduced. Stressful life events strongly associated with stress status were also discussed. In this study, it was clear that age, alcohol consumption, stress status and stressful life events caused higher blood pressure. On the other hand, the social network was associated with lifestyle status and a controlled blood pressure level. Obesity and physical exercise were significantly associated with serum lipids. There results suggest that it is very important for the maintenance and promotion of health and risk reduction of disease among the elderly to control socio-psychological factors such as stress and stressful life event, and that a social network helps maintain a healthy lifestyle.

[Normal CBF values by the ARG method using IMP SPECT: comparison with a conventional microsphere model method]

N-isopropyl-p[123I]iodoamphetamine (IMP) has been used as a flow tracer for SPECT, and measurement of cerebral blood flow (CBF) using IMP has been performed by conventional microsphere model method (MS method). Recently, the ARG method for measuring CBF by using IMP with one SPECT scan and one point blood sampling has been developed. This method was based on two-compartment model. In the present study, normal CBF values were measured in ten male healthy subjects (mean age +/- S.D.: 29.8 +/- 6.01, age range: 23-41) by the ARG and the MS methods. The mean CBF values (+/- S.D.) for the ARG method in which the Vd value was assumed to be 50 ml/ml were 41.7 +/- 9.4, 31.1 +/- 5.0, 40.7 +/- 9.7, 41.5 +/- 10.0, 38.2 +/- 9.2, 39.0 +/- 9.4, 41.9 +/- 10.6, 38.7 +/- 8.0 and 30.0 +/- 7.7 ml/100 ml/min in the cerebellum, pons, thalamus, basal ganglia, frontal, temporal, parietal, occipital lobe cortex and centrum semiovale, respectively. The mean CBF values for the MS method were 46.8 +/- 8.4, 37.5 +/- 5.6, 45.8 +/- 8.6, 46.5 +/- 8.9, 43.7 +/- 8.3, 44.4 +/- 8.7, 46.8 +/- 9.3, 44.3 +/- 7.3 and 36.3 +/- 8.1 ml/100 ml/min, respectively. The mean CBF values in the cerebral cortex region for the ARG method were lower than those previously reported by PET. This would be caused by low first-pass extraction fraction of IMP compared with oxygen-15 labeled water. The mean CBF values for the MS method were higher than those for the ARG method against previous studies. As reasons for this, errors in estimation of the SPECT brain counts at 8 min in the MS method were considered.

[A case of ACTH-producing thymic carcinoid tumor with Cushing syndrome]

ACTH-producing thymic carcinoid tumor with Cushing syndrome in a 41-year-old male was reported. Plasma ACTH and cortisol was high, and chest X-ray film and CT scan revealed a tumor mass in the anterior mediastinum. Extended thymectomy with pretracheal lymph node dissection was performed. The microscopic findings revealed that the mass was carcinoid tumor with metastasis of anterior mediastinal lymph node. ACTH and cortisol were restored to normal range 1 week after operation. Unfortunately, he admitted seven months later because of high level of ACTH and right supraclavicular lymph nodes swelling. He underwent right neck dissection. Pathological examination proved metastatic carcinoid tumors in the dissected nodes. It is important to perform supraclavicular lymph node dissection together with extended thymectomy for thymic carcinoid tumor.

Expression of oxytocin receptor in human pregnant myometrium

Around the onset of labor, uterine sensitivity to oxytocin (OT) increases tremendously. Although this is considered to reflect OT receptor (OTR) augmentation in myometrium, neither spatial expression of OTR nor the level of the receptor message during the course of pregnancy have been investigated at the molecular level. We examined the localization and expression of the OTR in human myometrium by means of in situ hybridization, immunohistochemistry, and Northern and Western blotting. In the term pregnant myometrium, OTR expressing smooth muscle cells are observed diffusely and heterogeneously. Some of the smooth muscle cells were expressed high levels of the receptor at the messenger RNA and protein level, and they were surrounded with cells weakly positive for the OTR or negative. The level of OTR transcripts increased according to the course of pregnancy. The receptor messenger RNA level reached over 300-fold at parturition compared with the nonpregnant myometrium. In the myometrium at 32 weeks of gestation and not in labor, a relatively large amount (about 100-fold) of the receptor message was expressed. In the nonpregnant myometrium, significant amount of the receptor protein was revealed by Western blotting. We also found that the receptor protein was augmented at term and after the onset of labor. These findings indicated that the expression of OTR changes dynamically at the transcription and protein level during pregnancy and that its expression is heterogeneous in the term myometrium.

Maintenance of imprinting of the insulin-like growth factor II gene (IGF2) and the small nuclear ribonucleoprotein polypeptide N gene (SNRPN) in the human uterus and leiomyoma

The insulin-like growth factor II gene (IGF2) is thought to be involved in the growth of uterine smooth muscle tumors. We studied the allele-specific expression of IGF2 in 20 patients with uterine leiomyomas by analyzing restriction fragment length polymorphisms (RFLP), because IGF2 is a maternally imprinted gene and only the paternal allele is exclusively expressed in human somatic tissue. We also studied the allelic expression of the small nuclear ribonucleoprotein polypeptide N gene (SNRPN), which is reportedly maternally imprinted in humans, and compared the imprinting status with that of IGF2. Nine patients (45%) were heterozygous at the ApaI site of IGF2, nine (45%) were heterozygous at the possible AccII polymorphic site of SNRPN, and three (15%) showed polymorphism in both genes. The genomic DNA of 15 patients showed heterozygosity in either or both of these genes, and the mRNA of these was expressed monoallelically in myometrial tissues and leiomyomas of these patients. These results demonstrated that IGF2 and SNRPN imprinting is completely maintained in human uteri and leiomyomas and that increased expression of IGF2 is not due to biallelic expression.