Conservative therapy for adenocarcinoma and atypical endometrial hyperplasia of the endometrium in young women: central pathologic review and treatment outcome

Thirty-nine patients with endometrioid adenocarcinoma (EA) and atypical hyperplasia (AH) of the endometrium who received conservative treatment to preserve fertility were collected from member institutions of the Japan Gynecologic Oncology Study Group. Twenty-nine and ten were originally diagnosed with EA without myometrial invasion and AH, respectively. We performed a central pathological review to make definite diagnoses, and the diagnosis of EA in 29 cases was changed to AH in ten, complex hyperplasia in three and atypical polypoid adenomyoma in three, and AH in ten was changed to EA in one and simple hyperplasia in one. Nine of 12 women (75%) with EA and 15 of 18 women (83%) with AH had an initial response to medroxyprogesterone acetate (MPA) treatment. Two of nine responders with EA later developed relapse, and one of them had metastasis to the left obturator lymph node. Two became pregnant, and one delivered one full-term infant. One of the responders with AH had a relapse in the endometrium. Five became pregnant, and four delivered four normal infants. The young women with endometrial carcinoma localized in the endometrium who wish to preserve fertility may be treated as successfully with MPA as those with AH.

Rapid one-step sandwich enzyme immunoassay for tissue inhibitor of metalloproteinases. An application for rheumatoid arthritis serum and plasma

A 1 h, one-step sandwich enzyme immunoassay was set up with a pair of monoclonal antibodies prepared against bovine tissue inhibitor of metalloproteinases (TIMP). TIMP in samples was allowed to react simultaneously with both solid-phase antibody and peroxidase-labeled Fab' of another antibody. Minimum sensitivity was 1 pg/well for bovine TIMP and 1.5 pg/well for human TIMP. The TIMP level in the sera of 38 rheumatoid arthritis (RA) patients (241 +/- 53 ng/ml, mean +/- SD) was significantly higher (P less than 0.001) than the level in the sera of 81 healthy subjects (175 +/- 39). A similar significant difference (P less than 0.001) was observed between the TIMP level in platelet-poor plasma of normal subjects (64 +/- 10) and that of RA patients (84 +/- 23), suggesting that the increase in TIMP seen in RA sera can not be ascribed merely to an increase in platelet-derived TIMP.

Molecular cloning of a novel trypsin-like serine protease (neurosin) preferentially expressed in brain

A cDNA encoding a precursor for a novel serine protease (neurosin) was cloned from a cDNA library prepared from a human colon adenocarcinoma cell line, COLO 201. The sequence consisted of 155 bp 5' non-coding region and a 732 bp open reading frame which was followed by a 551 bp 3' non-coding region. The predicted protein consists of 244 amino acids which is possibly processed to an active enzyme of 223 amino acids that shows some similarity (< 30%) to other members of serine protease family. As found in other trypsin-like proteases, the enzyme contains the catalytic triad which is characterized as the essential amino acid residues for the activity. Northern blot analyses of the mRNA showed the strongest expression in brain followed by a lower but significant one in spleen. A construct of cDNA encoding chimeric protein that carries pro-sequence of trypsin II and putative mature neurosin starting from Leu22 was transfected to COS-1 cells. Successful production of the active neurosin was shown after treating the supernatant of the culture of the transfectants with enterokinase.

Radiation-induced senescence-like growth arrest requires TP53 function but not telomere shortening

Suzuki, K., Mori, I., Nakayama, Y., Miyakoda, M., Kodama, S. and Watanabe, M. Radiation-Induced Senescence-like Growth Arrest Requires TP53 Function but not Telomere Shortening. Normal human diploid cells irradiated with X rays showed permanent cell cycle arrest and exhibited senescence-like phenotypes including the expression of senescence-associated beta-galactosidase (SA-beta-gal). X irradiation caused persistent phosphorylation of TP53 at Ser 15 and accumulation of the TP53 protein, followed by the induction of CDKN1A (also known as p21(Waf1/Cip1)) and CDKN2A (also known as p16), preceded the expression of SA-beta-gal. NCI-H1299 human lung carcinoma cells, in which no TP53 protein was expressed, were irradiated with X rays with or without the exogenous expression of TP53 gene. Although induction of TP53 protein alone could induce SA-beta-gal expression, the frequency of SA-beta-gal-positive cells was significantly increased when TP53-induced H1299 cells were exposed to X rays. The mean terminal restriction fragment length in normal human cells was approximately 12 kb and did not change in SA-beta-gal-positive cells. These results indicate that ionizing radiation induces senescence-like growth arrest that is dependent on TP53 function but independent of telomere shortening. Our findings suggest that cells harboring irreparable DNA damage are programmed to undergo premature senescence to maintain the integrity of the genome.

Reversal of established autoimmune diabetes by restoration of endogenous beta cell function

In NOD (nonobese diabetic) mice, a model of autoimmune diabetes, various immunomodulatory interventions prevent progression to diabetes. However, after hyperglycemia is established, such interventions rarely alter the course of disease or allow sustained engraftment of islet transplants. A proteasome defect in lymphoid cells of NOD mice impairs the presentation of self antigens and increases the susceptibility of these cells to TNF-alpha-induced apoptosis. Here, we examine the hypothesis that induction of TNF-alpha expression combined with reeducation of newly emerging T cells with self antigens can interrupt autoimmunity. Hyperglycemic NOD mice were treated with CFA to induce TNF-alpha expression and were exposed to functional complexes of MHC class I molecules and antigenic peptides either by repeated injection of MHC class I matched splenocytes or by transplantation of islets from nonautoimmune donors. Hyperglycemia was controlled in animals injected with splenocytes by administration of insulin or, more effectively, by implantation of encapsulated islets. These interventions reversed the established beta cell-directed autoimmunity and restored endogenous pancreatic islet function to such an extent that normoglycemia was maintained in up to 75% of animals after discontinuation of treatment and removal of islet transplants. A therapy aimed at the selective elimination of autoreactive cells and the reeducation of T cells, when combined with control of glycemia, is thus able to effect an apparent cure of established type 1 diabetes in the NOD mouse.

CD4(+) Valpha14 natural killer T cells are essential for acceptance of rat islet xenografts in mice

Pancreatic islet transplantation represents a potential treatment for insulin-dependent diabetes mellitus. However, the precise cellular and molecular mechanisms of the immune reactions against allogeneic and xenogeneic transplanted islets remain unclear. Here, we demonstrate that CD4(+) Valpha14 natural killer T (NKT) cells, a recently identified lymphoid cell lineage, are required for the acceptance of intrahepatic rat islet xenografts. An anti-CD4 mAb, administrated after transplantation, allowed islet xenografts to be accepted by C57BL/6 mice, with no need for immunosuppressive drugs. The dose of anti-CD4 mAb was critical, and the beneficial effect appeared to be associated with the reappearance of CD4(+) NKT cells at around 14 days after transplantation. Interestingly, rat islet xenografts were rejected, despite the anti-CD4 mAb treatment, in Valpha14 NKT cell-deficient mice, which exhibit the normal complement of conventional lymphoid cells; adoptive transfer of Valpha14 NKT cells into Valpha14 NKT cell-deficient mice restored the acceptance of rat islet xenografts. In addition, rat islet xenografts were accepted by Valpha14 NKT mice having only Valpha14 NKT cells and no other lymphoid cells. These results indicate that Valpha14 NKT cells play a crucial role in the acceptance of rat islet xenografts in mice treated with anti-CD4 antibody, probably by serving as immunosuppressive regulatory cells.

Radiation-induced long-lived radicals which cause mutation and transformation

Using electronic spin resonance (ESR), we found a new type of radical with a long life-time in cells (T1/2>20 h) and which may play a more important role in the induction of mutation and transformation than either the active, short-lived, H, or OH radicals. When cells were treated with dimethyl sulfoxide (DMSO) and l-ascorbic acid (AsA) just before irradiation, the short-lived radicals were well-scavenged. On the other hand, if cells were treated with the scavengers 20 min after irradiation, then AsA scavenged the long-lived radicals, but DMSO did not. AsA treatment 20 min after the start of irradiation drastically reduced both the frequencies of mutation at the hypoxanthine guanine phosphoribosyl transferase (HGPRT) locus in human cells and morphological transformations in mouse m5S cells, but DMSO treatment did not. In addition, AsA treatment 20 h after irradiation also reduced the mutation frequency in human cells. These results suggested that mutations and morphological transformation are probably caused by the presence of long-lived radicals in the cells, rather than by short lived radicals, and that AsA reacts efficiently with long-lived radicals, resulting in a decrease of the mutations and transformations induced.

Nasal immunization induces Haemophilus influenzae-specific Th1 and Th2 responses with mucosal IgA and systemic IgG antibodies for protective immunity

To determine the efficacy of a mucosal vaccine against nontypeable Haemophilus influenzae (NTHi), mice were immunized nasally, orally, intratracheally, or intraperitoneally with NTHi antigen together with cholera toxin. Antigen-specific IgA antibody titers in nasal washes and the numbers of antigen-specific IgA-producing cells in nasal passages showed the greatest increases in mice immunized nasally. Cytokine analysis showed that interferon-gamma, interleukin (IL)-2, IL-5, IL-6, and IL-10 were induced by nasal immunization, suggesting that Th2- and Th1-type cells were generated. Furthermore, bacterial clearance of a homologous strain of NTHi from the nasal tract was significantly enhanced in the nasal immunization group. These findings suggest that nasal immunization is an effective vaccination regimen for the induction of antigen-specific mucosal immune responses, which reduce the colonization of NTHi in the nasal tract.

Prognostic Factors of Stage IV Epithelial Ovarian Cancer: A Multicenter Retrospective Study

OBJECTIVE

In the present study, we conducted a multicenter retrospective analysis to elucidate the prognostic factors of stage IV epithelial ovarian cancer.

METHODS

In November 1999, 24 Japanese institutions received questionnaires regarding stage IV epithelial ovarian cancer patients. Eligibility criteria included all patients with stage IV epithelial ovarian cancer who were surgically confirmed and initially treated in each institution between January 1990 and December 1997. Data were collected regarding age, performance status, tumor histologic subtype, site of metastasis, preoperative CA125, cytoreductive surgery, residual disease after cytoreductive surgery, and response to primary chemotherapy. Survival analysis and comparisons were performed by univariate and multivariate methods.

RESULTS

Two hundred twenty-five patients with stage IV ovarian cancer were identified. The median age of the patients was 54 years. The most common site of extraperitoneal disease was malignant pleural effusion (39.6%). Of the 225 patients who underwent an attempt at surgical debulking, 70 (31.1%) were optimally cytoreduced. Most patients received platinum-based combination chemotherapy for primary chemotherapy. In multivariate analysis, performance status, histology, and residual disease after cytoreductive surgery were independent prognostic predictors of outcome. The overall median survival for optimally debulked patients was 32 months compared to 16 months for suboptimally debulked patients (P < 0.0001, hazard ratio: 0.415).

CONCLUSION

Optimal surgical debulking, performance status, and histology appear to be important prognostic factors of survival in patients with stage IV epithelial ovarian cancer.

Nasal immune system: distinctive Th0 and Th1/Th2 type environments in murine nasal-associated lymphoid tissues and nasal passage, respectively

The nasal mucosa, an important arm of the mucosal immune system, is the first site of contact with inhaled antigens to induce an IgA response. A major aim of this study was to characterize the Th1 and Th2 cytokine expression of mucosal T cells residing in nasal-associated lymphoid tissue (NALT) and nasal passages (NP) as IgA inductive and effector sites, respectively, at the transcription and cellular levels. An application of single-cell reverse transcription-PCR for analysis of Th1 (IFN-gamma) and Th2 (IL-4 and IL-6) cytokine-specific mRNA revealed the presence of CD4+ T cells with a Th0 profile in NALT, while high numbers of Th2 cytokine-specific mRNA expressed by CD4+ T cells were noted in NP followed by Th1-type cells. NALT CD3+ CD4+ T cells of Th0 type have the capacity to become Th1- and/or Th2-type cells since their activation via the TCR-CD3 complex resulted in the expression of an array of Th1 and Th2 cytokines. CD3+ CD4+ T cells from NP, but not NALT, provide a helper function for the induction of antibody-forming cells including IgA isotype in B cell cultures. These findings suggest that NALT is characterized by a Th0 environment which can gain a Th1 and/or Th2 phenotype. In contrast, NP is considered to be a Th2 dominant site with some Th1 cells that can support the induction of IgA-producing cells.

Recruitment of ATM protein to double strand DNA irradiated with ionizing radiation

The product of the ATM gene, which is mutated in ataxia telangiectasia, is a nuclear phosphoprotein, and it involves the activation of the p53 pathway after ionizing radiation. Here we show that the ATM protein is constitutively associated with double strand DNA and that the interaction increases when the DNA is exposed to ionizing radiation. The ATM protein also had affinity to restriction endonuclease PvuII-digested DNA, but not to UV-irradiated DNA nor X-irradiated single-stranded DNA. The immunoprecipitation experiment detected very weak association between ATM and DNA-PK proteins, and immunodepletion of DNA-PK showed little or no effect on the interaction of the ATM protein with damaged DNA, indicating that an interaction with DNA-PK might not be required for the recruitment of the ATM protein to damaged DNA. Furthermore, the association was also confirmed in xrs-5 and xrs-6e cells, which are Chinese hamster ovary mutant cell lines defective in Ku80 function. These results indicate that the ATM protein is recruited to the site of DNA damage and it recognizes double strand breaks by itself or through an association with other DNA-binding protein other than DNA-PK and Ku80 proteins.

Stress thallium-201 transaxial emission computed tomography: quantitative versus qualitative analysis for evaluation of coronary artery disease

Stress thallium-201 myocardial distribution was quantitatively evaluated by emission transaxial tomography in 104 patients who underwent coronary arteriography. The initial uptake and percent washout of thallium were assessed by the circumferential profile curves of the three short-axis sections and one middle right anterior oblique long-axis section. This quantitative tomographic analysis showed abnormal distribution in all but two patients (98%) with coronary artery disease, whereas qualitative analysis showed abnormality in 76 of the patients (93%). Quantitative analysis showed better sensitivity (91%) for detecting involved coronary vessels than qualitative analysis (80%, p less than 0.01), especially in three vessel disease (82 versus 67%, p less than 0.05). For localization of individual vessel involvement, quantitative analysis showed high sensitivity (right coronary artery: 96%, left anterior descending artery: 90% and left circumflex artery: 88%) as compared with qualitative analysis (88, 83 and 63%, respectively, p less than 0.05), while similar specificity was observed (92% for quantitative and 93% for qualitative analyses). Furthermore, in the study of patients without infarction, myocardial segments supplied by coronary vessels with moderate stenosis (51 to 75%) revealed abnormality more often with quantitative (81%) than with qualitative (56%) analysis. Thus, quantitative analysis of stress thallium emission tomography provides improved sensitivity for the detection of diseased coronary vessels in patients with three vessel disease and those with moderate stenosis. It is a valuable technique for the evaluation of coronary artery disease.

Phase III randomised controlled trial of neoadjuvant chemotherapy plus radical surgery vs radical surgery alone for stages IB2, IIA2, and IIB cervical cancer: a Japan Clinical Oncology Group trial (JCOG 0102)

Background:

A phase III trial was conducted to determine whether neoadjuvant chemotherapy (NACT) before radical surgery (RS) improves overall survival.

Methods:

Patients with stage IB2, IIA2, or IIB squamous cell carcinoma of the uterine cervix were randomly assigned to receive either BOMP (bleomycin 7 mg days 1–5, vincristine 0.7 mg m⁻² day 5, mitomycin 7 mg m⁻² day 5, cisplatin 14 mg m⁻² days 1–5, every 3 weeks for 2 to 4 cycles) plus RS (NACT group) or RS alone (RS group). Patients with pathological high-risk factors received postoperative radiotherapy (RT). The primary end point was overall survival.

Results:

A total of 134 patients were randomly assigned to treatment. This study was prematurely terminated at the first planned interim analysis because overall survival in the NACT group was inferior to that in the RS group. Patients who received postoperative RT were significantly lower in the NACT group (58%) than in the RS group (80% P=0.015). The 5-year overall survival was 70.0% in the NACT group and 74.4% in the RS group (P=0.85).

Conclusion:

Neoadjuvant chemotherapy with BOMP regimen before RS did not improve overall survival, but reduced the number of patients who received postoperative RT.

A clinicopathologic study of 30 patients with Paget's disease of the vulva

Clinical and pathologic analyses were performed in 30 patients with Paget's disease of the vulva to investigate the risk factors for recurrence. From 1971 to 1993, we carried out histologic examinations in 27 resected vulvae to detect Paget's cells at the surgical margin. Prior to 1981, 9 patients underwent the examination, and 6 of them had positive surgical margins, and 2 of these 6 patients had local recurrence. After 1982, the preoperative multiple biopsy and intraoperative frozen section diagnosis of the surgical margins were performed, and as a result, cases of the lesions remaining as stumps on the vaginal side decreased in 7 of 18 examined patients. In these 7 cases, 2 cases had local recurrence. The patients were further divided into three groups according to histologic findings to investigate their prognosis: 10 patients with intraepithelial Paget's disease (IEP), 9 patients with minimally invasive Paget's disease (MIP), and 11 patients with underlying carcinoma (UC) including 2 cases of carcinoma in situ. Four locally recurrent cases were found in IEP or MIP, and the longest period from surgery to recurrence was 8 years and 4 months. The invasive UC lesions persisted or recurred shortly after surgery (median, 10 months) and 5 of the 6 patients with general metastasis. For IEP and MIP, surgical margins of the vaginal side should be carefully examined with preoperative multiple biopsy and intraoperative frozen section, and also a long-term follow-up is necessary. With regard to invasive UC patients, their prognosis was found to be very poor for general metastasis.

Quantitative relationship between body weight gain in adulthood and incident type 2 diabetes: a meta-analysis

This meta-analysis quantified the risk of type 2 diabetes mellitus (T2DM) preceded by body weight (BW) gain in the general population. Systematic literature searches retrieved 15 eligible studies. The BW gain was divided into early weight-gain, which was defined as BW gain from early adulthood (18-24 years of age) to cohort entry (≥25 years of age), and late weight-gain, which was defined as BW gain from cohort entry. The pooled relative risk (RR; 95% confidence interval [CI]) of T2DM for an increment of BW gain standardized into a 5-kg m(-2) increment in the body mass index (BMI) was 3.07 (2.49-2.79) for early weight-gain and 2.12 (1.74-2.58) for late weight-gain. When limiting analysis to studies that concurrently examined T2DM risk for current BMI (defined in both groups as BMI at cohort entry), a larger magnitude of T2DM risk was revealed for early weight-gain compared with current BMI (RR [95% CI], 3.38 [2.20-5.18] vs. 2.39 [1.58-3.62]), while there was little difference between late weight-gain (RR [95% CI], 2.21 [1.91-2.56]) and current BMI (RR [95% CI], 2.47 [1.97-3.30]). The meta-analysis suggested that BW gain was a quantifiable predictor of T2DM, as well as current obesity in adults. Particularly, BW gain in early rather than middle-to-late adulthood played an important role in developing T2DM.

Characterization of a recombinant soluble form of human placental leucine aminopeptidase/oxytocinase expressed in Chinese hamster ovary cells

Serum levels of human placental leucine aminopeptidase/oxytocinase (P-LAP) increase with gestation. cDNA cloning of P-LAP revealed that the enzyme is a type II membrane-bound protein containing the consensus HEXXH(X)18E motif found in the M1 family of zinc-metallopeptidase proteins. In this study, a recombinant soluble form of P-LAP found in maternal serum was expressed in Chinese hamster ovary cells, purified to homogeneity and then characterized. Although N-terminal sequencing revealed a four-amino-acid deletion, the purified enzyme was active and was shown to be a zinc-containing homodimeric protein with molecular mass of 280 kDa in solution. Using artificial substrates, it was shown that the enzyme has broad specificity and is inhibited by several compounds known as aminopeptidase inhibitors. Subsequently, sequential N-terminal amino-acid liberation of several peptide hormones by the enzyme was monitored and structures of the products were determined. Among the hormones having a cysteine residue at their N-terminal end and intramolecular disulfide bonds, it was found that vasopressin and oxytocin, but not calcitonin and endothelins, were cleaved by the enzyme. Because the molecular properties of oxytocinase so far reported often conflict, our results provide an initial biochemical and enzymatic characterization of moleculary defined P-LAP/oxytocinase.

HbA(1c) variability and the development of microalbuminuria in type 2 diabetes: Tsukuba Kawai Diabetes Registry 2

AIMS/HYPOTHESIS

The aim of this study was to examine the association between HbA(1c) variability and the development of microalbuminuria as defined by an albumin/creatinine ratio ≥ 3.4 mg/mmol (≥ 30 mg/g) in at least two of three consecutive urine samples in Japanese patients with type 2 diabetes.

METHODS

HbA(1c) level was measured in 812 serially registered normoalbuminuric adults aged 21-79 years with type 2 diabetes. After registration, a 1-year period to establish baseline values for mean HbA(1c) and HbA(1c) variability (measured as the intrapersonal SD of serially collected HbA(1c)) was decided upon. The association between HbA(1c) variability and the development of microalbuminuria was determined by Cox regression analysis after adjustment for other risk factors for microalbuminuria.

RESULTS

Microalbuminuria occurred in 193 patients during the observation period of (mean ± SD) 4.3 ± 2.7 years. Even after adjustment for mean HbA(1c), HbA(1c) variability was a significant predictor of microalbuminuria independently of the mean HbA(1c); the HR for every 1% (95% CI) increase in mean HbA(1c) was 1.22 (1.06, 1.40) (p = 0.005), and that for HbA(1c) variability was 1.35 (1.05, 1.72) (p = 0.019). The effects of these two variables were quite similar when 1 SD was used; the HR for every 1 SD increase (95% CI) in HbA(1c) was 1.23 (1.07, 1.43) (p = 0.005), and that for HbA(1c) variability was 1.20 (1.03, 1.39) (p = 0.019).

CONCLUSIONS/INTERPRETATION

HbA(1c) variability affects the development of microalbuminuria independently of mean HbA(1c) in type 2 diabetes. Further studies should be performed to evaluate the influence of HbA(1c) variability on other complications and in individuals of other ethnicities with type 2 diabetes.

Effects of ketogenic diet on electroconvulsive threshold and brain contents of adenosine nucleotides

The anticonvulsive effect of a ketogenic diet was investigated using mice fed on a ketogenic milk powder which contained medium-chain triglycerides (MCT). Electroconvulsive shocking and determination of adenosine nucleotides in mice brain were performed on three mice groups, (1) a control group; free access to a commercially available diet, (2) a fasted group; fasted for two days, and (3) a ketotic group; fasted for two days and then fed on the ketogenic milk powder for two weeks. The maximal electroconvulsive threshold of the ketotic group was significantly higher than that of the fasted group (p less than 0.001). The maximal electroconvulsive threshold of the fasted group was significantly higher than that of the control group (p less than 0.05). The contents of adenosine triphosphate (ATP) in the brain of the ketotic group was significantly higher than that of the control group (p less than 0.01). These results suggest that chronic ketosis with the ketogenic diet increases the contents of ATP in the brain and this increase in ATP probably accounts for the neuronal stability.

The therapeutic potential of tumor necrosis factor for autoimmune disease: a mechanistically based hypothesis

Excess levels of tumor necrosis factor-alpha (TNF-alpha) have been associated with certain autoimmune diseases. Under the rationale that elevated TNF-alpha levels are deleterious, several anti-TNF-alpha therapies are now available to block the action of TNF-alpha in patients with autoimmune diseases with a chronic inflammatory component to the destructive process. TNF-alpha antagonists have provided clinical benefit to many patients, but their use also is accompanied by new or aggravated forms of autoimmunity. Here we propose a mechanistically based hypothesis for the adverse events observed with TNF-alpha antagonists, and argue for the opposite therapeutic strategy: to boost or restore TNF-alpha activity as a treatment for some forms of autoimmunity. Activation defects in the transcription factor nuclear factor kappaB leave autoreactive T cells sensitive to TNF-alpha-induced apoptosis. Treatment with TNF-alpha, by destroying autoreactive T cells, appears to be a highly targeted strategy to interrupt the pathogenesis of type 1 diabetes, lupus and certain forms of autoimmunity.

Insulin down-regulates insulin receptor substrate-2 expression through the phosphatidylinositol 3-kinase/Akt pathway

Insulin receptor substrate (IRS)-1 and IRS-2 are the major substrates that mediate insulin action. Insulin itself regulates the expression of the IRS protein in the liver, but the underlying mechanisms of IRS-1 and IRS-2 regulation are not fully understood. Here we report that insulin suppressed the expression of both IRS-1 and IRS-2 proteins in Fao hepatoma cells. The decrease in IRS-1 protein occurred via proteasomal degradation without any change in IRS-1 mRNA, whereas the insulin-induced suppression of IRS-2 protein was associated with a parallel decrease in IRS-2 mRNA without changing IRS-2 mRNA half-life. The insulin-induced suppression of IRS-2 mRNA and protein was blocked by the phosphatidylinositol (PI) 3-kinase inhibitor, LY294002, but not by the MAP kinase-ERK kinase (MEK) inhibitor, PD098059. Inhibition of Akt by overexpression of dominant-negative Akt also caused complete attenuation of the insulin-induced decrease in IRS-2 protein and partial attenuation of its mRNA down-regulation. Some nuclear proteins bound to the insulin response element (IRE) sequence on the IRS-2 gene in an insulin-dependent manner in vitro, and the binding was also blocked by the PI 3-kinase inhibitor. Reporter gene assay showed that insulin suppressed the activity of both human and rat IRS-2 gene promoters through the IRE in a PI 3-kinase-dependent manner. Our results indicate that insulin regulates IRS-1 and IRS-2 through different mechanisms and that insulin represses IRS-2 gene expression via a PI 3-kinase/Akt pathway.

Myocardial positron computed tomography with 13N-ammonia at rest and during exercise

To assess the value of myocardial-perfusion positron computed tomography (PCT) for the evaluation of coronary artery disease (CAD), 13N-ammonia PCT using a whole-body multislice PCT device was performed at rest and during exercise in 6 normal subjects and 19 patients with angiographically documented CAD. The 13N-ammonia distribution in the myocardium was assessed both qualitatively and quantitatively. At rest and during exercise, the tracer distribution was homogeneous in the 6 normal cases. In the 19 patients with CAD, regional hypoperfusion was observed in 14 cases (74%) at rest and in 18 cases (95%) during exercise. Additional perfusion abnormalities were detecting during exercise in 12 cases. Segmental analysis of the myocardial perfusion identified 30 out of 34 stenosed vessels (88%) during exercise, with only one false-positive finding of diseased vessels (specificity, 98%). For the quantitative analysis of myocardial perfusion by PCT, the percentage of change in the tracer concentration in the same region between the rest and stress images was calculated. The concentration was slightly increased in normal myocardial segments (14.4% +/- 5.8%; P less than 0.001), whereas in CAD, it was significantly decreased in segments with stenosed vessels (-18.0% +/- 18.3%; P less than 0.02). We conclude that 13N-ammonia PCT at rest and during exercise provides high-quality images, and is a sensitive and effective technique for detecting CAD and identifying individual stenosed vessels. Furthermore, this technique makes possible quantitative assessment of the coronary reserve function.

Induction of specific immunoglobulin A and Th2 immune responses to P6 outer membrane protein of nontypeable Haemophilus influenzae in middle ear mucosa by intranasal immunization

Nontypeable Haemophilus influenzae (NTHI) is a major pathogen of otitis media. One of the outer membrane proteins of NTHI, P6, is an antigen common to all strains and is considered as a candidate for mucosal vaccine. To elucidate the possibility of developing a nasal vaccine against nontypeable Haemophilus influenzae (NTHI) and to investigate mucosal immune responses in the middle ear, mice were immunized intranasally with the P6 outer membrane protein of NTHI, and P6-specific immune responses in the middle ear mucosa were examined. Mice were given with P6 and cholera toxin intranasally as an adjuvant on days 0, 7, and 14 and were killed on day 21. The P6-specific immunoglobulin A (IgA) antibody titer in ear wash was significantly elevated. Mononuclear cells were isolated from middle ear mucosa, and an increase in P6-specific IgA-producing cells was shown with an enzyme-linked immunospot assay. In addition, an increase in memory T cells in middle ear mucosa was detected with flow cytometric analysis after intranasal immunization. Moreover, in vitro stimulation with P6 resulted in proliferation of purified CD4(+) T cells from immunized mice, and these T cells expressed Th2 cytokine mRNA. These results indicate that P6-specific IgA-B-cell immune responses and selected Th2 cytokine expressing Th cells were induced in middle ear mucosa by intranasal immunization. These findings suggest that a nasal vaccine is useful for preventing otitis media with effusion.