Hypermutable myotonic dystrophy CTG repeats in transgenic mice.

Myotonic dystrophy (DM) is one of a growing number of inherited human disorders associated with the expansion of triplet repeat DNA sequences. Expanded alleles are highly unstable in both the germline and soma, accounting in large part for the unusual genetics of this disorder, its phenotypic variability and probably, the progressive nature of the symptoms. However, the molecular mechanisms and the genetic factors modulating repeat stability in DM and the other human disorders associated with expanded repeats are not well understood. To provide a model system in which the turnover of triplet repeats could be studied throughout mammalian development, we have generated five transgenic mouse lines incorporating expanded CTG/CAG arrays derived from the human DM locus. Transgene analysis has revealed germline hypermutability, including expansions, deletions and parent-of-origin effects, somatic and early embryonic instability and segregation distortion. Mutational differences between lines and sexes demonstrate that stability, as in humans, is modulated by as yet unidentified cis and trans acting genetic elements.

Prevalence of Sjogren syndrome among Nagasaki atomic bomb survivors.

OBJECTIVES: Through a comprehensive epidemiological study, we determined Sjögren syndrome (SS) prevalence and examined the association between SS and ionising radiation dose. METHODS: A total of 1008 atomic bomb survivors in Nagasaki agreed to undergo the tests comprising a questionnaire for xerophthalmia and xerostomia, Schirmer-I test, Saxon test, and tests of anti-SS-A/Ro and anti-SS-B/La antibodies, and, if necessary, Rose Bengal stain test, salivary ultrasonographic and MRI examination from November 2002 through October 2004. Diagnosis of SS was based on the American-European Consensus Group criteria, or a modified version thereof. RESULTS: Among the 1008 participants (male 398, female 610, average age 71.6 years), 154 participants (15.3%) complained of xerophthalmia, and 264 (26.2%) of xerostomia. Reduced tear flow as assessed by the Schirmer-I test was detected in 371 of 992 participants (37.4%) and reduced saliva flow as assessed by the Saxon test in 203 of 993 participants (20.4%). Among all participants, 38 (3.8%) and 10 (1.0%) participants tested positive for anti-SS-A/Ro and anti-SS-B/La antibodies, respectively. Taking into consideration all the results, 23 participants were diagnosed with SS (primary 20, secondary 3), yielding a prevalence of 2.3%. Although the association between SS and radiation dose was not significant, radiation dose was significantly associated with hyposalivation. CONCLUSIONS: The present comprehensive epidemiological study reveals that the prevalence of SS was 2.3% among Nagasaki atomic bomb survivors and was not associated with radiation dose. The association between radiation dose and hyposalivation supported the possibility that radiation exposure damaged salivary gland function.

Prevalence of adult-onset multifactorial disease among offspring of atomic bomb survivors.

The first study to examine whether parental radiation exposure leads to increased heritable risk of common adult-onset multifactorial diseases (i.e., hypertension, diabetes mellitus, hypercholesterolemia, ischemic heart disease, and stroke) was conducted among 11,951 participants in the clinical examination program out of a potential of 24,673 mail survey subjects who were offspring of survivors born from May 1946 through December 1984. Logistic regression analyses demonstrated no evidence of an association between the prevalence of multifactorial diseases in the offspring and parental radiation exposure, after adjusting for age, city, gender and various risk factors. The odds ratio (OR) for a paternal dose of 1 Gy was 0.91 [95% confidence interval (CI) 0.81-1.01, P = 0.08], and that for a maternal dose of 1 Gy was 0.98 (95% CI 0.86-1.10, P = 0.71). There was no apparent effect of parental age at exposure or of elapsed time between parental exposure and birth, but male offspring had a low odds ratio (OR = 0.76 at 1 Gy) for paternal exposure, but cautious interpretation is needed for this finding. The clinical assessment of nearly 12,000 offspring of A-bomb survivors who have reached a median age of about 50 years provided no evidence for an increased prevalence of adult-onset multifactorial diseases in relation to parental radiation exposure.

Interaction of human beta 1 thyroid hormone receptor and its mutants with DNA and retinoid X receptor beta. T3 response element-dependent dominant negative potency.

Mutations in the human beta thyroid hormone receptor (h-TR beta) gene are associated with the syndrome of generalized resistance to thyroid hormone. We investigated the interaction of three h-TR beta 1 mutants representing different types of functional impairment (kindreds ED, OK, and PV) with different response elements for 3,3',5-triiodothyronine (T3) and with retinoid X receptor beta (RXR beta). The mutant receptors showed an increased tendency to form homodimers on a palindromic T3-response element (TREpal), a direct repeat (DR + 4), and an inverted palindrome (TRElap). On TRElap, wild type TR binding was decreased by T3, while the mutant receptors showed a variably decreased degree of dissociation from TRElap in response to T3. The extent of dissociation was proportional to their T3 binding affinities. RXR beta induced the formation of h-TR beta 1:RXR beta heterodimers equally well for mutants and the wild type h-TR beta 1 on these T3 response elements. However, the T3-dependent increase in heterodimerization with RXR beta was absent or reduced for the mutant TRs. Transient transfection studies indicated that the dominant negative potency was several-fold more pronounced on the TRElap as compared to TREpal or DR + 4. In CV-1 and HeLa cells, transfection of RXR beta could not reverse the dominant negative action. These results demonstrate that the binding of mutant h-TRs to DNA, as well as their dominant negative potency, are TRE dependent. In addition, competition for DNA binding, rather than for limiting amounts of RXR beta, is likely to mediate the dominant negative action.

Variable transcriptional activity and ligand binding of mutant beta 1 3,5,3'-triiodothyronine receptors from four families with generalized resistance to thyroid hormone.

Mutations in the gene encoding the human beta 1 T3 receptor (hTR beta 1) have been associated with generalized resistance to thyroid hormone (GRTH). We measured the T3-binding affinity and transcriptional regulatory capacity of the mutant hTR beta 1 from four unrelated kindreds with GRTH. These mutations are contained in different functional regions of the ligand-binding domain. The T3 affinity of the mutant receptors correlated well with the degree of impairment of their trans-activating function in a transient cotransfection system in HeLa cells; two mutant receptors with undetectable ligand affinity showed no transcriptional activity, whereas the two other mutants characterized by a 2- and 5-fold reduction in T3 affinity required 5- and 15-fold higher T3 concentrations for half-maximal activity in the cotransfection assay, respectively. All of the mutant hTR beta 1s were able to inhibit the function of transfected normal hTR beta 1 and endogenous retinoic acid receptor in activating a palindromic positive T3 response element (TRE). In the partially functional mutants this dominant negative effect could be completely reversed by increased T3 concentrations. The dominant negative potency did not depend on the type of TRE used; mutant hTR beta 1s were able to inhibit normal receptor function to the same degree on a dimer-permissive palindromic TRE as on a nondimer-permissive inverted repeat of two identical half-sites separated by five spacer bases. However, the dominant negative potency was dependent on the absolute amount of receptor expression vector transfected. The expression of normal and mutant hTR beta 1 was assessed by immunocytochemistry. The hTR beta 1 protein levels in HeLa cells paralleled the amount of transfected expression vector. Moreover, all the mutant receptors were properly expressed in the nuclei of the transfected cells. These data suggest that different mutations in the ligand-binding domain of the human hTR beta 1 result in a variable degree of functional impairment, which may partially explain the phenotypic differences between kindreds with GRTH. Our findings suggest that competition for binding to the TRE and possibly the binding of limiting accessory factors may be more important in mediating the dominant negative effect than the formation of normal/mutant T3 receptor dimers.

Normal radiographic anatomy of thoracic structures: analysis of 1000 chest radiographs in Japanese population.

The purpose of this paper was to study the frequency of visualization and characteristics of normal thoracic structures on posteroanterior (PA) chest radiographs in Japanese population. 1000 consecutive normal PA chest radiographs of men and women ranging in age from 20 years to 90 years were reviewed. Frequency of visualization and configuration of structures including (1) fissure lines such as major, minor, vertical fissure line, and accessory fissures, (2) vascular structures including normal apical opacity, aortic nipple, and descending aortic interface, and (3) other structures including air in the oesophagus, aortic pulmonary stripe, and diaphragm were studied. On PA chest radiographs: (1) minor fissure, superolateral major fissure, superomedial major fissure, vertical fissure line, superior accessory fissure, and inferior accessory fissure were visualized in 74.7%, 19.7%, 15.4%, 1.6%, 2.9% and 13.1%, respectively. (2) Normal apical opacity was seen in 3.7%, while aortic nipple was seen in 0.9%. Descending aortic interface was obliterated in 13.7%. (3) Air in the oesophagus and aortic pulmonary stripe were seen in 8.9% and 17.7%, respectively. Hemidiaphragm was obliterated in 10.3% on the right, and in 32.4% on the left. Scalloping of the diaphragm was seen in 10.6% on the right, 6.5% on the left, and 4.3% bilaterally. Frequency of visualization and characteristics of various normal anatomical structures on chest radiographs in Japanese population differ from those reported previously from the West. Familiarity with these normal thoracic structures and variations is important for our daily image interpretation.

Studies on homologous desensitization of the thyrotropin receptor in 293 human embryonal kidney cells.

It is well known that the TSH receptor (TSHR) undergoes homologous desensitization. That is, prolonged stimulation of thyroid cells with TSH attenuates the cAMP response to subsequent TSH stimulation. However, the existence of homologous desensitization of the recombinant TSHR expressed in nonthyroidal eukaryotic cells is controversial. In the present studies, therefore, we first investigated whether or not the TSHR was desensitized by TSH in 293 human embryonal kidney cells, a cell line in which the LH/CG receptor (LH/CGR) is reported to undergo homologous desensitization. The wild type (wt) TSHR and the wt-LH/CGR stably expressed in 293 cells bound to their respective hormones with high affinity and produced a dose-dependent intracellular cAMP response to hormone stimulation. Pretreatment of cells expressing the TSHR or the LH/CGR with their respective hormones attenuated the cAMP response to subsequent hormone stimulation without down-regulation of the receptors, demonstrating that the TSHR, as well as the LH/CGR, undergoes homologous desensitization in 293 cells. With this cell type expressing mutant TSHRs, we then studied some aspects of the molecular mechanism of TSHR desensitization and compared our data to those obtained with the beta-adrenergic receptor (beta-AR), which is widely regarded as the prototype for receptor desensitization. We cotransfected the wt-TSHR and a chimeric receptor consisting of the LH/CGR extracellular ligand binding domain with the TSHR transmembrane/cytoplasmic signal transducing region. These two receptors have distinct hormone specificities but share common signal regulatory mechanisms. We observed that, like the beta-AR, only hormone-occupied receptor is likely to be involved in homologous desensitization. On the other hand, studies with a truncated TSHR indicated that, in contrast to the beta-AR, the serine/threonine-rich region in the carboxyl two thirds of the cytoplasmic tail of the TSHR is not involved in homologous desensitization.

Glucose stimulation of protooncogene expression and deoxyribonucleic acid synthesis in rat islet cell line.

The rat islet cell line, RIN, established from a transplantable, radiation-induced islet cell tumor represents a unique model to study mechanisms in the control of insulin secretion and biosynthesis. In this study, we have examined the effects of glucose on the protooncogene expressioN and cell growth using a clonal strain of RIN cell, RINr, under serum-free and glucose-free conditions. After 24 h pretreatment, cells were treated with different concentrations of glucose for up to 24 h and then subjected to RNA analysis. Agarose gel electrophoresis of total RNA extracts of RINr cells, followed by hybridization with v-myc DNA yielded a 2.4 kilobase c-myc messenger RNA (mRNA) transcripts. After 24 h pretreatment with serum-free and glucose-free medium, RINr cells expressed a low level of c-myc mRNA transcripts. An increase in c-myc transcripts was detectable within 30 min of D-glucose (200 mg/dl) addition, reaching a maximum of 10-fold within 2 h. Glucose stimulated the steady state of c-myc mRNA transcripts in a dose-responsive manner without any change of gamma-actin mRNA levels after 2 h of treatment. The level of c-myc transcripts then declined as the cells proceeded through G1 to the cycle. [3H]Thymidine uptake into DNA was dramatically increased after 24 h of glucose addition, suggesting that glucose itself stimulates DNA synthesis in RINr cells. These results indicate that glucose-induced proliferation of RINr cells is associated with the stimulation of c-myc gene expression.

Role of apoptosis of thyrocytes in a rat model of goiter. A possible involvement of Fas system.

Apoptosis, a physiological process of cell death, may modulate the mass of the thyroid gland. We investigated the role of apoptosis and the possible involvement of Fas/Fas ligand (FasL) system in apoptosis during goiter formation and involution in a rat model of goiter. Rats were fed a low iodine diet and a goitrogen, 6-propyl-2-thiouracil, to induce goiter. Rats with goiter were then fed a high iodine diet to study the phase of involution. We examined the presence of apoptosis by electron microscopy (EM) and terminal deoxy-UTP nick end labeling (TUNEL). We also investigated the association between Fas and FasL expression and thyrocyte apoptosis using immunohistochemistry and Western blotting. To evaluate the proliferation of thyrocytes, proliferating cell nuclear antigen was examined immunohistochemically. The number of apoptotic cells increased during goiter formation and the early stage of involution, which were also associated with increased number of Fas-positive thyrocytes, and some of these cells contained TUNEL-positive nuclei. However, the expression of FasL was almost constant throughout the experiment. Proliferating cell nuclear antigen/TUNEL ratio markedly increased during goiter formation but decreased particularly during the late stage of goiter involution. Our results indicate that apoptosis of thyrocytes is a main factor of cell loss during goiter formation and involution and suggest that the Fas/FasL system is involved in the induction of apoptosis of these cells. Moreover, the delicate balance between apoptosis and cell proliferation may play an important role in the control of thyroid gland mass.

Interferon-gamma inhibits thyrotropin-induced thyroidal peroxidase gene expression in cultured human thyrocytes.

We have previously demonstrated that interferon-gamma (IFN-gamma) induced HLA-DR antigen and also inhibited thyrotropin (TSH)-induced triiodothyronine (T3) and thyroglobulin (Tg) secretion from cultured human thyrocytes. In order to further clarify the inhibitory effect of IFN-gamma on TSH-stimulated thyroid hormone secretion, we have examined human thyroid peroxidase (TPO) gene expression. Thyrocytes dispersed from Graves' thyroid tissues were incubated with TSH with or without IFN-gamma. Total RNA was extracted, separated and hybridized with 32P-labelled human TPO cDNA. Thyrocytes expressed four TPO mRNA transcripts (4.0, 3.2, 2.1 and 1.7kb, respectively), all of which were stimulated by TSH. IFN-gamma inhibited TSH-stimulated TPO mRNA in a dose dependent manner (0.01-10U/mL). 1 U/mL IFN-gamma caused maximal suppression of TSH-stimulated TPO mRNA levels to basal levels. IFN-gamma also inhibited 8-bromo-cyclic AMP-stimulated TPO mRNA levels. In contrast, the gamma-actin mRNA hybridization signal was not altered in control or treated cells. These results demonstrate that IFN-gamma directly inhibits TSH-stimulated TPO gene expression and provide further support for a role of IFN-gamma as a local modulator of thyroid hormone synthesis.

Prevalence of goiter and urinary iodine excretion levels in children around Chernobyl.

The prevalence of goiter among children living in areas affected by the Chernobyl accident was investigated by analysis of data on approximately 120,000 children examined at five medical diagnostic centers in Belarus, Russia, and the Ukraine. Examinations of thyroid gland were conducted with an arch-automatic ultrasonographic instrument at the five centers under the same protocol. The diagnosis of goiter was established when the thyroid volume exceeded a limit calculated from age, height, and body weight of a child. A considerable variation by region was noted in the prevalence of goiter. Highest in the Kiev region, the prevalence in the five regions was 54% in Kiev, 38% in the Zhitomir regions of the Ukraine, 18% in Gomel, 22% in the Mogilev regions of Belarus, and 41% in the Bryansk region of Russia. Urinary iodine content was measured in approximately 5700 children, and an endemic iodine deficient zone was confirmed in the Bryansk, Kiev, and Zhitomir regions. A significant negative correlation was observed between the prevalence of goiter and the median level of urinary iodine content (Spearman's rank correlation coefficient was -0.35, P = 0.025).

Untreated Graves' disease patients without clinical ophthalmopathy demonstrate a high frequency of extraocular muscle (EOM) enlargement by magnetic resonance.

12 of 17, a significant frequency (71%), of untreated Graves' disease patients with no clinical ophthalmopathy showed extraocular muscle (EOM) enlargement by Magnetic Resonance Imaging (MRI). Enlargement was bilateral in 41% and unilateral in 29% in these patients. Apparent enlargements of EOM were also detected, by MRI, in all of 11 Graves' disease patients with clinical ophthalmopathy, bilateral in 73% and unilateral in 27% of patients in this group. Both group showed the inferior rectus muscle as the most frequently involved (56% and 77% respectively). In 16 patients without autoimmune thyroid disorders or ophthalmopathy who served as normal controls, only 2 of these patients (12%) demonstrated mild EOM enlargement. The severity and patterns of EOM enlargement revealed no correlation with abnormalities in serum thyroid function tests or serum thyroidal autoantibodies. In conclusion, a high frequency of Graves' disease patients without clinical eye signs or symptoms harbor EOM abnormalities, as demonstrated by MRI. This suggests that present clinical examination methods are insufficient to diagnose varying degrees of ophthalmopathy in patients with autoimmune thyroid disorders who do not initially present with clinical ophthalmopathy.

Inhibitory effect of interferon-gamma on the response of human thyrocytes to thyrotropin (TSH) stimulation: relationship between the response to TSH and the expression of DR antigen.

Thyroid epithelial cells (thyrocytes) in autoimmune thyroid disease have been found to express DR antigens on their surfaces, and interferon-gamma (IFN gamma) induces DR antigen expression. This study was undertaken to determine the effect of IFN gamma on the response of human thyrocytes to TSH stimulation and the relationship between the response to TSH and the expression of DR antigen induced by IFN gamma, using monolayer cultures of Graves' thyrocytes. When confluent thyrocyte monolayers were incubated with TSH or Bu2cAMP (DBcAMP) for 7-9 days, T3 and thyroglobulin concentrations in the culture medium increased gradually in a dose-dependent manner. However, when TSH or DBcAMP was added after the cells had been cultured for 4 days with IFN gamma, T3 and thyroglobulin secretion in response to both 10 mU/mL TSH and 1 mM DBcAMP was significantly inhibited. The inhibition by IFN gamma was dose dependent and correlated with the number of DR antigen-positive thyrocytes present on the last day of culture. IFN alpha and -beta did not affect the response of thyrocytes to TSH or DBcAMP stimulation. These results suggest that DR antigen-positive thyrocytes fail to respond to TSH stimulation at a site located distal to cAMP formation.

Presence of protein phosphatase type 1 and its involvement in temperature-dependent flagellar movement of fowl spermatozoa.

Even in the presence of ATP, the motility of demembranated fowl spermatozoa was negligible at the avian body temperature of 40 degrees C. Motility could be restored by the addition of calyculin A, okadaic acid, specific inhibitors of phosphatase type 1 (PP1) and PP-2A, and inhibitor 1 or inhibitor 2, which are specific inhibitors of protein phosphatase type 1 (PP1). Demembranated spermatozoa, stimulated by calyculin A or okadaic acid, lost their motility following the addition of 1 mM CaCl2, but this was restored gradually by the stepwise addition of EGTA. Immunoblotting of sperm extract using an antibody to PP1 revealed a major cross-reacting protein of 36-37 kDa, which corresponded to the molecular weight of the known catalytic subunit of PP1. These results suggest that PP1 present in the fowl sperm axoneme may be involved in the inhibition of fowl sperm motility at 40 degrees C via Ca(2+)-dependent regulatory systems.

Interleukin-1 inhibits thyrotrophin-induced human thyroglobulin gene expression.

The regulation of thyroglobulin (Tg) and its specific mRNA by interleukin-1 (IL-1) in cultured human thyrocytes was investigated. Specific binding of 125I-labelled IL-1 on thyrocytes was confirmed by solid-phase binding assay. Thyrocytes dispersed from Graves' thyroid tissues were incubated with TSH with or without recombinant human IL-1. TSH stimulated Tg release from cultured human thyrocytes in a dose- and time-dependent manner. Both IL-1 alpha and beta inhibited TSH-induced Tg release at concentrations ranging from 0.01 to 10 U/ml. The suppressive activities of IL-1 alpha and beta were similar. They did not alter the basal level of Tg release. Unstimulated human thyrocytes did not contain any detectable Tg mRNA, but TSH-stimulated thyrocytes expressed a single species of Tg mRNA (8.5 kb). Both IL-1 alpha and beta inhibited TSH-induced Tg mRNA in a dose-responsive manner. IL-1 (10 U/ml) caused maximal suppression of TSH-induced Tg mRNA to nearly basal levels. In contrast, the gamma-actin mRNA hybridization signal was not altered in control or treated cells. Furthermore, IL-1 stimulated [3H]thymidine uptake into thyrocyte DNA. These results demonstrate that IL-1 directly inhibits TSH-induced Tg gene expression and provide further support for a functional role of IL-1 as a local modulator of thyroid hormone synthesis.

A case of solitary pulmonary lymphangioma.

Solitary pulmonary lymphangiomas are rare benign lesions thought to result from the development of abnormally proliferating lymphatic vessels. This report describes a case of solitary pulmonary lymphangioma resected under video assisted thoracoscopic surgery and diagnosed using histological and immunohistochemical investigations.

Automated lung segmentation in digital lateral chest radiographs.

We are developing a fully automated computerized scheme for segmenting the lung fields in digital lateral chest radiographs. Existing computer-aided diagnostic (CAD) schemes and automated lung segmentation methods have focused exclusively on the posteroanterior view, despite the diagnostic importance of the lateral view. Information from the lateral radiograph is routinely incorporated by radiologists in their decision-making process, and thus computer analysis of lateral images may potentially add another dimension to current CAD schemes. Automated analysis of the lung fields in lateral images will necessarily require accurate segmentation. Our scheme employs an initial procedure to eliminate external and subcutaneous pixels. Global gray-level histogram analysis then allows for the identification of a range of gray-level thresholds. An iterative gray-level thresholding scheme is implemented using this range of thresholds to construct a series of binary images in which contiguous regions are identified and geometrically analyzed. Regions determined to be outside the lungs are prevented from contributing to binary images at later iterations. Adaptive local gray-level thresholding is applied along the initial contour that results from the global thresholding procedure to extend the contour closer to the true lung borders. This local thresholding method uses regions of interest of various dimensions, depending on the enclosed anatomy. Smoothing and polynomial curve fitting complete the segmentation. A database of 100 normal and 100 abnormal lateral images was analyzed. Quantitative comparison of computer-segmented lung regions with lung regions manually delineated by two radiologists indicated that 83% and 84% of normal and abnormal images, respectively, displayed segmentation contours within three standard deviations of the mean inter-radiologist contour degree-of-overlap value.

High affinity binding of thyrotropin (TSH) and thyroid-stimulating autoantibody for the TSH receptor extracellular domain.

There have been some controversial data as to whether the extracellular domain of the thyrotropin receptor (TSHR) is sufficient for constituting the high affinity binding site(s) for TSH and thyroid-stimulating antibody (TSAb). The present study was, therefore, designed to further evaluate the functional significance of the TSHR extracellular domain. The new chimeric receptor (designated TSHEX-LHTMR) consisting of the human (h) TSHR extracellular domain and the rat lutropin/choriogonadotropin (LH/CG) receptor transmembrane region was constructed, stably expressed in Chinese hamster ovary cells, and tested for its abilities to bind TSH and hCG and to increase intracellular cAMP production in response to hormone and TSAb stimulation. The binding affinity for TSH and the ability to produce cAMP in response to TSH stimulation in the chimeric receptor TSHEX-LHTMR was comparable to those in the wild-type (wt) TSHR (Kd = approximately 0.3 nM and EC50 = approximately 3 nM). The TSHEX-LHTMR and the wt-TSHR also demonstrated similar TSAb activity. However, the TSHEX-LHTMR, unlike the wt-LH/CGR, did not bind hCG or respond to hCG stimulation. These results demonstrate that the functional properties of the TSHR are not affected by the replacement of the receptor transmembrane region with the corresponding region of the LH/CGR, suggesting, together with other previous reports, that the TSHR extracellular domain appears to be of primary importance for the high affinity binding for TSH and TSAb, although the TSHR transmembrane region can contribute to high affinity binding and also bioactivity for TSH and TSAb.

ret rearrangements in Japanese pediatric and adult papillary thyroid cancers.

Oncogenic rearrangements of the ret proto-oncogene (ret/PTC) are found uniquely in papillary thyroid carcinomas. The prevalence of ret/PTC in these tumors varies widely, from 0% to 87%, among patient series from different geographical regions. The differences in the prevalence of ret rearrangement have been ascribed to age, genetic, and/or environmental factors. The very high prevalence of ret/PTC in tumors arising in children after the Chernobyl nuclear accident has generated speculation that this oncogene may be an indicator of overt or inadvertent radiation exposure. In Japan, the prevalence of ret activation is reportedly quite low (0% to 9%). Here we examined the frequency of ret rearrangements in papillary carcinomas from Japanese adults and children by means of reverse transcription polymerase chain reaction (RT-PCR) followed by Southern hybridization. Ret rearrangements were detected in 4 of 11 (36%) tumors from the adult population, and in 3 of 10 (30%) pediatric tumors. One child with a solid variant papillary carcinoma had a ret-PTC3 rearrangement, further supporting the association between the solid variant histotype and this particular rearrangement of ret. The present data do not support a major geographic difference in the prevalence of ret/PTC rearrangements in papillary carcinomas between Japan, the United States, and Italy.

Treatment with propylthiouracil is associated with appearance of antineutrophil cytoplasmic antibodies in some patients with Graves' disease.

The use of propylthiouracil (PTU) for the treatment of Graves' disease is associated with few adverse effects such as skin eruptions, liver dysfunction, and agranulocytosis. Furthermore, recent studies described the development of antineutrophil cytoplasmic antibody (ANCA)-related glomerulonephritis and vasculitis in patients treated with PTU. Here we investigated whether PTU therapy per se is associated with the appearance of ANCA in patients with Graves' disease. We analyzed 119 serum samples from 117 patients with Graves' disease treated with either PTU (n = 56), or methimazole (MMI) (n = 21), as well as untreated patients (n = 42). Myeloperoxidase (MPO)-ANCA and proteinase 3 (PR3)-ANCA were tested by enzyme-linked immunosorbent assay (ELISA) kits. MPO-ANCA was negative in all patients treated with MMI therapy and untreated patients. However, MPO-ANCA was detected in 21 (37.5%) of 56 patients treated with PTU therapy. Furthermore, two patients who were negative for MPO-ANCA became positive after PTU therapy. The proportion of patients positive for MPO-ANCA increased with the prolongation of PTU therapy, but did not correlate with age, gender, and positive antithyroperoxidase (TPO) antibody. Among 21 MPO-ANCA positive patients, 12 had no symptoms, but 9 patients complained of myalgia, arthralgia, or common cold like symptoms after the appearance of MPO-ANCA. Three patients developed agranulocytosis or granulocytopenia, but none showed abnormal urinary findings. Our results suggest that PTU per se is associated with the production of MPO-ANCA in patients with Graves' disease.