Effects of ketoprofen for prevention of postoperative cognitive dysfunction in aged rats.

Postoperative cognitive dysfunction is a common geriatric complication that may be associated with increased mortality. Here, we investigated the effects of postoperative analgesia with ketoprofen on cognitive functions in aged animals and compared its effectiveness to morphine. Rats were randomly allocated to one of four groups: isoflurane anesthesia without surgery (group C), isoflurane anesthesia with laparotomy (group IL), and isoflurane anesthesia with laparotomy plus postoperative analgesia with ketoprofen or morphine. There was no difference in postoperative locomotor activity among groups. In group IL, postoperative pain levels assessed by the Rat Grimace Scale significantly increased until 8 h after surgery, which was similarly inhibited by both ketoprofen and morphine. Cognitive function was assessed using radial arm maze testing for 12 consecutive days from postoperative day 3. Results showed that the number of memory errors in group IL were significantly higher than those in goup C. However, both ketoprofen and morphine could attenuate the increase in memory errors following surgery to a similar degree. Conversely, ketoprofen showed no effect on cognitive function in the nonsurgical rats that did not experience pain. Our findings suggest that postoperative analgesia with ketoprofen can prevent the development of surgery-associated memory deficits via its pain-relieving effects.

Preventive effects of multisensory rehabilitation on development of cognitive dysfunction following systemic inflammation in aged rats.

Systemic inflammation can trigger transient or longer-lasting cognitive impairments, particularly in elderly patients. However, its pathogenesis has not been sufficiently clarified. In this study, we explored the potential effects of multisensory rehabilitation on cognitive dysfunction following systemic inflammation using an animal model. Aged male Wister rats were randomly injected intraperitoneally with either saline (control) or lipopolysaccharide (LPS; 5 mg/kg). After injection, both groups of rats were randomly assigned to either of two housing conditions (n = 8 in each condition): a standard cage environment (SC group) or a multisensory early rehabilitation environment (ER group). Cognitive function was examined after 7 days in the assigned environmental condition using a novel object recognition test. In the SC group, the LPS-treated rats showed impaired cognitive function compared with the control animals. These memory deficits were positively correlated with the levels of both tumor necrosis factor (TNF)-α and interleukin (IL)-1ß in the hippocampus. On the other hand, in the LPS-treated ER group, neither cognitive impairment nor an increase in hippocampal levels of both TNF-α and IL-1ß was found. These results imply that early rehabilitation (ER) intervention may be effective in preventing cognitive dysfunction following systemic inflammation via its anti-neuroinflammatory effects.

Periventricular echodensity measured with the integrated backscatter system: from a qualitative assessment to a quantitative approach.

BACKGROUND: The degree of periventricular white matter echodensity in preterm infants has been utilized as a sign of the early ultrasonographic appearance of periventricular leukomalacia, and this has been called periventricular echodensity (PVE). OBJECTIVES: The aim of this study was to quantitatively measure PVE utilizing a new method which is called calibrated integrated backscatter (calibrated IB). METHODS: Eighty-eight preterm infants (extremely low birth weight infants, n = 17; very low birth weight infants, n = 26; low birth weight infants, n = 45) without any CNS abnormality were enrolled. IB is the returned sound pressure against supersonic waves sent from an ultrasonographic machine. The IB of the choroid plexus and periventricular white matter in the subrolandic area were measured on a parasagittal cerebral image. The degree of PVE was defined by subtracting the IB of the choroid plexus from that of the periventricular white matter in the subrolandic area (calibrated IB of PVE). RESULTS: The intraobserver and interobserver correlations were both excellent (between 0.87 and 0.98 as correlation coefficients). There was a trend for the calibrated IB of PVE to decrease in accordance with time after birth, with a significant difference in very low birth weight and low birth weight infants. CONCLUSIONS: The objectively measured brightness of PVE was comparable to that of the choroid plexus irrespective of the size of the infants. Measurement of the calibrated IB of PVE might be a reliable method to assess PVE.

Association of cord blood cytokine levels with wheezy infants in the first year of life.

As antenatal environment may influence the development of atopy-predisposing immune response, cord blood cytokine productions may be an important predictor for wheezing. We investigated cord blood cytokines in a prospective birth cohort, intensively monitored for wheezy infant outcome at 1 yr. Cord blood serum samples from 269 children were assayed for interleukin (IL)-1beta, -2, -4 to -8, -10, -12 (p70), -13, and -17, interferon-gamma, tumor necrosis factor-alpha, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor (G-CSF), monocyte chemotactic protein-1, and macrophage inflammatory protein-1beta. Associations between family histories, antenatal and perinatal factors, cord blood cytokine concentrations, and wheezy infant outcomes (wheezing more than two times) were analyzed. In cord blood sera from 269 children, there were associations between high levels of IL-6, -8 and G-CSF concentrations, and cesarean section. Data at 1 yr were obtained from 213 infants, including 33 wheezy infants. Risk of wheezing was related to gestational age, birth weight, cesarean section, and maternal eczema, but not to bacterial/viral infection during pregnancy, maternal asthma, maternal smoking, or paternal history. High level of cord blood IL-8 concentration had a significant association with wheezy infant outcomes at 1 yr (p = 0.025). By using multivariate logistic regression analysis, birth weight [odds ratio(OR) = 0.998, 95% confidence interval (CI) = 0.997-1.000] and maternal eczema (OR = 5.356, 95% CI = 1.340-21.41), but no other factors, were significant predictors of wheezy infants. Birth weight, gestational age, and maternal history were important risk factors for wheezing in the first year of life. Several cord blood cytokine productions were influenced by cesarean section, and IL-8 may be a predictor for recurrent wheezing at 1 yr.

Hepatocyte growth factor treatment improves alveolarization in a newborn murine model of bronchopulmonary dysplasia.

BACKGROUND: Bronchopulmonary dysplasia (BPD) is thought to be one form of developmental arrest of the lung. Hepatocyte growth factor (HGF) participates in normal lung growth and in lung regeneration. OBJECTIVES: The purpose of this study is to investigate whether HGF can improve alveolarization and attenuates functional abnormalities of a murine model of BPD induced by hyperoxia. METHODS: Three-day-old CD-1 mice were exposed to 90% of oxygen or room air (control group) for 7 days. These animals were then kept in room air for the next 7 days. Recombinant human (rh) HGF (100 microg/g b.w., divided 3 times, rhHGF group) or vehicle (vehicle group) was administered intraperitoneally during hyperoxia. On day 17, the pulmonary function test and bronchial hyperresponsiveness (BHR) were examined. Mean linear intercepts (MLI) were measured as parameters of alveolarization. Cell renewal (on day 10) and vascularization of the lung were also evaluated. RESULTS: Exposure to hyperoxia induced increased airway resistance and BHR. These animals showed a severely simplified alveolar structure, increased MLI, decreased cell renewal (16.1 +/- 2.4 vs. 29.6 +/- 2.4%, p < 0.05), and decreased vascularization (15.1 +/- 0.3 vs. 18.4 +/- 1.5 vessels/hpf, p < 0.05, vehicle vs. control group, respectively). rhHGF treatment during exposure to hyperoxia significantly reduced all of these changes (27.9 +/- 1.7%, 18.2 +/- 0.5 vessels/hpf for cell renewal and vascularization, respectively; all values are p < 0.05 against vehicle animals). CONCLUSION: HGF partially protects against the inhibition of alveolarization and improves functional abnormality in the hyperoxia-induced neonatal mice model of BPD.

Adolescent wilms tumor with intraspinal and bone metastases: a case report and the review of literature.

A 14-year-old girl was referred for a large tumor of the left kidney, with intraspinal and vertebral metastases. Left nephrectomy and intraspinal tumor resection were performed. The histology of both tumors was nephroblastoma with no anaplasia and favorable histology, and they were diagnosed as stage IV. The tumor bed and vertebras were irradiated. We started chemotherapy according to the DD-4A regimen of Japanese Wilms' Tumor Study Group. The vertebral metastasis was additionally irradiated. The patient has remained in disease-free remission for 45 months after the surgical resection. Intensive multimodality therapy including DD-4A regimen of National Wilms' Tumor Study can result in long-term disease-free remission.

Double-stranded RNA and TGF-alpha promote MUC5AC induction in respiratory cells.

Viral infection is a major trigger for exacerbation of asthma and induces overproduction of mucins. We investigated whether dsRNA could amplify the induction of mucin by TGF-alpha in human bronchial epithelial cells, as well as the molecular mechanisms regulating MUC5AC expression. Human pulmonary mucoepidermoid carcinoma (NCI-H292) cells and normal human bronchial epithelial cells were exposed to polyinosinic-cytidyric acid (poly(I:C)) and TGF-alpha. Then, MUC5AC protein production, mRNA expression, and promoter activity were evaluated. Cells were pretreated with a selective inhibitor of ERK, and phosphorylation of ERK was examined by Western blotting. Furthermore, the expression of MAPK phosphatase 3 (MKP3) mRNA was evaluated and the effect of MKP3 overexpression was assessed. Poly(I:C) synergistically increased MUC5AC induction by TGF-alpha in both NCI-H292 and normal human bronchial epithelial cells. This increase was dependent on MUC5AC gene transcription. A MEK1/2 inhibitor (U0126) significantly inhibited MUC5AC production. Phosphorylation of ERK was enhanced by poly(I:C). TGF-alpha stimulation up-regulated MKP3 mRNA expression, while costimulation with poly(I:C) inhibited this up-regulation dose-dependently. Enhanced expression of MUC5AC mRNA by poly(I:C) in wild-type cells was completely suppressed in cells transfected with the MKP3 expression vector. dsRNA can synergistically amplify the induction of MUC5AC mucin by TGF-alpha. This synergistic effect on MUC5AC production may be due to enhanced activation of ERK through inhibition of MKP3 by poly(I:C).

Effects of SO2 on respiratory system of adult Miyakejima resident 2 years after returning to the island.

BACKGROUND: Mt. Oyama in Miyakejima Island erupted in June, 2000. All Miyake villagers were forced to evacuate from the island in September, 2000, due to continuous eruptions and emissions of unsafe amounts of volcanic gas, mainly SO2. From February, 2005, Miyake villagers returned to the island despite volcanic gas still being emitted. OBJECTIVES: This study examines the 2-yr changes in Miyake residents' respiratory systems from autumn 2004 to November 2006. METHODS: The study population was 823 Miyake adult residents who participated in the health check-up in 2006. Respiratory effects were evaluated by a questionnaire for respiratory symptoms and spirometry. SO2 has been continuously monitored at 7 sampling points of the inhabited area. The mean SO2 concentration from February 2005 to November 2006 was 0.031 ppm. The area was categorized into 4 areas by SO2 concentration, namely, areas L, H-1, H-2 and H-3, where average SO2 concentrations were 0.019, 0.026, 0.032, and 0.045 ppm, respectively. RESULTS: The study subjects showed no deterioration in lung function. Prevalence of cough and phlegm among all participants were significantly higher in 2006 than in 2004, and age-, sex- and smoking-adjusted odds ratios of cough and phlegm were 1.75 (95%CI 1.33-2.30) and 1.44 (1.12-1.87). Prevalence of chronic bronchitis-like symptoms among normosusceptive subjects in 2006 was 4.1% which was significantly higher than that of 2.1% in 2004 (p=0.035). Compared to area L, the frequencies of phlegm and irritation of the nose were significantly increased in areas H-2 and H-3. CONCLUSION: SO2 exposure-related respiratory symptoms were observed in adult Miyakejima residents after returning to the island.

The effects of intestinal ischemia on colonic motility in conscious rats.

BACKGROUND: The present study aimed to examine whether and how colonic motility is affected by mild ischemia-induced intestinal injury in conscious rats through in vivo monitoring of colonic contractions, specifically with regard to the interstitial cells of Cajal (ICC) and the effect of nitric oxide (NO). METHODS: Using miniature strain-gauge transducers, colonic motility with or without ischemia was recorded in conscious rats on the 4th, 7th, and 14th days after surgery. Histological examination for c-kit-positive cells was performed. RESULTS: In control nonischemic rats, the number and duration of contractions (NC and DC, respectively) decreased gradually, but the mean amplitude of contractions (MC) and motility index (MI) did not change. On the 7th day, the NC in the ischemic group increased significantly when compared with that in the control group (P = 0.037). The DC in the ischemic group was lower than that in the control group; the difference was significant on the 4th day (P = 0.008). The MIs in the ischemic group were lower than those in the control group. In both groups, administration of NGnitro-L: -arginine methyl ester on the 7th day increased only the resting cecal motility. Pathological examinations revealed c-kit-positive cells in both groups. CONCLUSIONS: Changes such as increased NC with shortened DC accompanied with decreased MI must have occurred at the ischemic site and might have been induced by an ischemic event. However, there exists a possibility that ICC and NO do not play a role in mild ischemia-induced dysmotility.

Increased serum monocyte chemoattractant protein-1, macrophage inflammatory protein-1beta, and interleukin-8 concentrations in hemophagocytic lymphohistiocytosis.

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is characterized by hypercytokinemia caused by macrophage and T cell activation. We analyzed the serum concentrations of monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1beta, and interleukin (IL)-8 to investigate the roles of these chemokines in the pathophysiology of HLH. METHODS: Seven patients clinically diagnosed with HLH were examined. Serum cytokines and chemokines were measured. The differences in the serum concentrations between the patients with HLH and the controls were investigated. RESULTS: In patients with an active phase of HLH, the serum MCP-1, MIP-1beta, and IL-8 levels all were significantly higher than in healthy controls. The chemokine elevations decreased rapidly after initiation of chemotherapy. During increases in disease activity, elevation of MCP-1 and MIP-1beta preceded elevation of the serum ferritin level, which is a clinical indicator of HLH disease activity. CONCLUSIONS: These results suggest that MCP-1, MIP-1beta, and IL-8 play important roles in the pathophysiology of HLH. In addition, the serum concentrations of these chemokines may be sensitive markers for assessing disease activity in patients with HLH.

Left displacement of the mediastinum determines the imbalance in the pulmonary vascular bed and lung volume in children with pectus excavatum.

The purpose of this study was to determine the influence of morphologic alteration on lung function in children with pectus excavatum (PE) and to establish the usefulness of chest radiography to predict the imbalance of pulmonary perfusion and lung volume. Chest radiography, pulmonary perfusion scintigraphy, and computed tomography (CT) for calculation of each lung volume were performed in 38 children with PE. To assess the relationship between position change of the mediastinum and lung, the following indices were calculated: (1) vertebral index (VI); the severity of sternal depression on the lateral chest radiograph, (2) left displacement index (LDI); the ratio between the left border of the mediastinum and the left border of the thorax to the transverse thoracic dimension on posterioanterior chest radiography; (3) left-to-right count ratio for the lung scintigraphy (Ls/Rs), and (4) the left-to-right thorax volume ratio from the CT scan (Lv/Rv). Compared to children without PE, VI was significantly higher, and LDI was lower in patients with PE. Pulmonary perfusion scintigraphy and CT showed that left pulmonary perfusion and lung volume were significantly lower than in the right lung in PE. LDI showed a close correlation with Ls/Rs (R = 0.443, P = 0.005) and Lv/Rv (R = 0.703, P < 0.001). Left displacement of the mediastinum within the closed thoracic cavity directly imposes constraints on the left lung, resulting in reductions of perfusion and lung volume that likely determine the physiologic severity of lung function in PE. Posterioanterior chest radiography might be useful in predicting the severity of PE.

Pemphigus vulgaris as a possible cause of protein-losing gastroenteropathy: a case report.

We present a case of pemphigus vulgaris (PV) accompanied with protein-losing gastroenteropathy (PLE). A 9-year-old girl developed multiple oral ulcerations and erosions. She was first treated with oral antibiotics and a topical steroid without improvement. Laboratory data showed eosinophilia (absolute eosinophil count 1.08 x 10(9)/L) and hypoproteinemia (total serum protein 3.9 g/dL, albumin 2.2 g/dL). A biopsy specimen from the ileum showed intense eosinophil infiltration and albumin scintigraphy demonstrated protein exduation from the same site. Endoscopic examination of the oesophagus showed multiple ulcerations and erosions, and biopsy specimen showed eosinophilic spongiosis and immunohistologic staining demonstrated deposits of IgG and C3 in the intercellular space. Antidesmoglein-3 antibody elevated, she was diagnosed as PV complicated with PLE. Immunofluorescence study of a biopsy specimen from the terminal ileum showed no significant immunoglobulin or complement deposition, and autoantibody against intestinal mucosa was unclear in this case. Gastrointestinal evaluations should be considered in patients with hypoproteinemia associated with PV.

Differential regulation of eotaxin expression by dexamethasone in normal human lung fibroblasts.

Lung fibroblasts are a major source of several cytokines including CC chemokine eotaxin. We aimed to study the regulation of eotaxin-1/CCL11 production by dexamethasone and analyze its molecular mechanisms in human lung fibroblasts. Normal human lung fibroblast cells were exposed to IL-4 (40 ng/ml) and/or dexamethasone (10(-6)-10(-9) M), and eotaxin mRNA expression and production was evaluated. Mechanisms of transcriptional regulation were assessed by Western blotting and dual luciferase assay for eotaxin promoter. The effects of dexamethasone on suppressor of cytokine signaling (SOCS)-1 and eotaxin mRNA expression in the cells transfected with expression vector (pAcGFP1-C1) or short interfering RNA (siRNA) for SOCS-1 were also investigated. Within 24 hours, dexamethasone inhibited IL-4-induced eotaxin mRNA expression and protein production, while eotaxin production was markedly increased at 48 and 72 hours after coincubation with IL-4 and dexamethasone. IL-4-induced eotaxin promoter activity was inhibited by dexamethasone at 8 hours, but enhanced at 48 hours after coincubation. Dexamethasone suppressed SOCS-1 mRNA expression but enhanced IL-4-induced STAT6 phosphorylation at 36 to 48 hours after coincubation. Enhanced expression of eotaxin mRNA by dexamethasone 48 hours after coincubation was completely diminished in the cells transfected with either expression vector or siRNA for SOCS-1. These results indicated that dexamethasone, depending on the exposure duration, can either inhibit or enhance IL-4-induced expression and production of eotaxin in the lung fibroblasts. The mechanisms of later enhanced production may depend on the prolonged transcriptional activity of the eotaxin gene, in part due to inhibition of SOCS-1 expression.

Does leukotriene affect intracellular glutathione redox state in cultured human airway epithelial cells?

Leukotrienes (LTs) are one of the most important mediators in the pathophysiology of asthma. We measured the intracellular amounts of reduced glutathione (GSH) and oxidized glutathione (GSSG) in cultured human airway epithelial cells. LTC 4 affects the GSH/GSSG ratio by activating signals to increase interleukin-8 (IL-8) production. Pretreatment with a reducing agent, glutathione monochrome ester (GSH-OEt), and with a leukotriene receptor antagonist, montelukast, significantly suppressed LTC(4)-induced time-dependent changes in the intracellular redox state, and also suppressed upregulation of IL-8 production by suppressing NF-kappaB activation. Our observations led to the hypothesis that LTC(4)-induced oxidative stress is likely to contribute to amplification of airway inflammation.

Gradual improvement of liver function after administration of ursodeoxycholic acid in an infant with a novel ABCB11 gene mutation with phenotypic continuum between BRIC2 and PFIC2.

OBJECT: The authors report the case of a boy with PFIC type 2 or BRIC type 2 who suffered from liver dysfunction at 2 months after birth. METHODS AND RESULTS: A liver biopsy specimen revealed mild liver cirrhosis, and the findings resembled those observed in Byler disease. Genetic examination revealed a normal familial intrahepatic cholestasis-1 gene, but a heterozygous mutation for the ABCB11, C1620A (F540L), was observed. Therefore, the patient was initially diagnosed with PFIC type 2. For 3 years after the diagnosis, he had severe pruritus, an increased serum bile acid, and normal serum values of gamma-glutamyl transaminase. At the age of 2, treatment with administration of ursodeoxycholic acid was started; subsequently, a gradual improvement in his liver function was observed. At the age of 3, he suffered from massive intestinal and pulmonary hemorrhage, which improved immediately after the administration of vitamin K. He was then admitted to our hospital for liver transplantation. At 1 month after the admission, his liver dysfunction showed further improvement, except for a mild increase in the serum bile acid level. This condition did not show any change during the 5-year follow-up period. In addition, the patient showed severe growth failure and was diagnosed with growth hormone deficiency. Hence, he receives growth hormone administration. CONCLUSION: The patient could be genetically diagnosed with bile salt export pump disease of PFIC type 2 or BRIC type 2. Various clinical features are observed in PFIC or BRIC patients with ABCB11 mutation.

Study of nasopharyngeal bacterial flora. Variations in nasopharyngeal bacterial flora in schoolchildren and adults when administered antimicrobial agents.

Changes in nasopharyngeal bacterial flora in adults with acute upper respiratory tract infection on administration of antimicrobial agents were investigated, and how these changes contrasted with those in children. Many patients with acute sinusitis due to allergies, and patients with malignancy and diabetes mellitus were included in the investigation. The detection rates of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, the major bacteria of acute otitis media (AOM), were 22%, 10%, and 7% respectively, which were significantly lower than those for children. Gram stain examination of nasopharyngeal swab samples showed a significant relation between leukocyte infiltration and the detection amount of S. pneumoniae (P = 0.0086). A significant relation (P = 0.0134) was also observed when H. influenzae was simultaneously detected. No significant change in the three major AOM bacteria present in nasopharyngeal bacterial flora after administration of antimicrobial agents was observed. However, all S. pneumoniae and H. influenzae detected after antimicrobial agent administration had the beta-lactam-resistance gene. It was observed that a significant improvement in leukocyte infiltration occurred 6 to 10 days after antimicrobial agent administration. In contrast, a significant improvement in children was observed at 2 to 5 days. In the adult subjects, this improvement was probably due to spontaneous remission rather than the effect of the antimicrobial agents. Although investigation of the long-term administration of antimicrobial agents was also conducted, its benefits for the patients were not elucidated.

Age-related difference in the persistency of allergic airway inflammation and bronchial hyperresponsiveness in a murine model of asthma.

AIM: Asthmatic children are more likely to outgrow their symptoms than adult patients. Thus, we wanted to know whether there were any age-related differences in the time course of the allergic airway inflammation. METHODS: BALB/C mice at different ages (young: 3 days after birth, and mature: 8 weeks of age) were sensitized with ovalbumin (OVA). Subsequently, animals were challenged with aerosolized OVA during 1, 2, 4 or 8 consecutive weeks. Bronchial hyperresponsiveness (BHR), serum IgE levels, the degrees of inflammatory cell infiltration (ICI) and goblet cell metaplasia (GCM) in the airways, and the number of eosinophils and cytokine levels in bronchoalveolar lavage fluid (BALF) were examined. RESULTS: At 1 week, airway inflammation and BHR occurred similarly between young and mature mice. However, BHR disappeared at 4 weeks in young, whereas it persisted even at 8 weeks in mature mice. GCM, ICI and eosinophilia in BALF attenuated with time, with more remarkable reduction in young mice. The BALF IL-4 level was high during the first 2 weeks in both groups, while the IL-2 level was significantly increased at 2 weeks solely in young mice. CONCLUSION: Different time courses in airway inflammation and in BHR may relate to the different prognoses between childhood and adult asthma. The understanding of the mechanisms underlying this age-related differences may be helpful to induce remission in asthmatic patients.

Identification and functional analysis of novel inactivating thyrotropin receptor mutations in patients with thyrotropin resistance.

OBJECTIVE: We identified and analyzed novel thyrotropin (TSH) receptor mutations in three Japanese families with resistance to TSH. DESIGN: The TSH receptor gene was sequenced and the mutations were determined. The mutant TSH receptors were transfected into COS-7 cells, and their functions were analyzed. PATIENTS: The patients were compound-heterozygotes for the R450H mutation and novel mutations in the TSH receptor gene. The first patient was a compound-heterozygote for R450H and V473I. The second sibling possessed R450H and R519C. The third sibling had R450H and R519G. RESULTS: The R450H mutant exhibited moderately impaired receptor functions and a moderately decreased cell surface expression in agreement with previous results. The V473I mutant exhibited an almost normal TSH binding, a slightly decreased cyclic adenosine monophosphate (cAMP) response, a moderately decreased inositolphosphate (IP) response, and an almost normal cell surface expression. TSH binding and TSH stimulation of cAMP and IPs were markedly decreased in the R519C and R519G mutants. Cell surface expression was decreased in the R519C mutant and negligible in the R519G mutant. All of these mutants showed normal intracellular synthesis of TSH receptors. CONCLUSIONS: These novel inactivating mutations contribute to understanding of the structure-function relationship of the TSH receptor. To date, all of the patients with TSH resistance resulting from TSH receptor mutations identified in Japan possessed the R450H mutation at least in one allele. These observations suggest that the R450H mutation is a commonly observed TSH receptor mutation in patients with TSH resistance in Japan.