Effect of aerobic exercise training followed by a low-calorie diet on metabolic syndrome risk factors in men

BACKGROUND AND AIMS

Whether low-volume, high-intensity, interval training (HIIT) is an adequate exercise method for improving metabolic risk factors is controversial. Moreover, it is not known if performing a short-term, low-calorie diet intervention (LCDi) after a HIIT program affects risk factors. This study investigated how an 8-week, 3 times/week exercise intervention (EXi) incorporating either HIIT or moderate-intensity continuous training (MICT) followed by a 4-week LCDi affects risk factors.

METHODS AND RESULTS

Twenty-six male workers with metabolic risk factors (47.4 ± 7.1 years; cardiorespiratory capacity (VO2peak) of 28.5 ± 3.9 ml/kg/min) were randomly assigned to either the HIIT (3 sets of 3-min cycling with a 2-min active rest between sets, 180 kcal) or MICT (45 min, 360 kcal) group. After the EXi, all subjects participated in a 4-week LCDi (4 counseling sessions). During the EXi, VO2peak improved more (P < 0.05) through HIIT (25.4 ± 14.6%) than through MICT (14.9 ± 12.8%), whereas improvements in body fat and HDL cholesterol were similar. During the LCDi, some risk factors improved further (P < 0.05) without any group differences, while VO2peak in the HIIT group decreased (P < 0.05) to the same level as in the MICT group.

CONCLUSION

VO2peak increased more with HIIT than with MICT during the EXi despite HIIT having a lower exercise volume than MICT, but this advantage of HIIT promptly disappeared through detraining. An intervention strategy consisting of 8 weeks of either HIIT or MICT followed by a 4-week LCDi has a positive effect on metabolic risk factors.

CLINICAL TRIAL REGISTRATION

UMIN11352.

Functional variants in the thromboxane A2 receptor gene are associated with lung function in childhood-onset asthma

BACKGROUND

The thromboxane A2 receptor (TBXA2R) gene is associated with asthma, but no functional genetic variations are known to associate with the disease or its related phenotypes.

OBJECTIVE

To investigate the association of TBXA2R polymorphisms with asthma susceptibility and related phenotypes and to identify functionally relevant polymorphisms.

METHODS

We performed comprehensive sequencing of the TBXA2R gene in 48 Japanese control subjects and found a set of variants (SNP1 G>T rs2238634, SNP2 T>G rs2238633, SNP3 C>T rs2238632 and SNP4 G>A rs2238631) in intron 1 in linkage disequilibrium with c.795 T>C rs1131882, which was previously reported to be associated with asthma and related phenotypes. To investigate the effect of four common haplotypes (H1, H2, H3 and H4) on transcriptional activity, we performed a luciferase assay in primary bronchial smooth muscle cells (BSMCs) and human airway epithelial cells (BEAS-2B). We also studied the haplotype association with lung function, TBXA2R mRNA levels, and eosinophil fraction/count in peripheral blood in childhood-onset asthma patients and/or controls.

RESULTS

H2 and H4, containing minor alleles of SNP2 and SNP3, had significantly higher transcriptional activities than H1 consisting of major alleles (P < 0.001 in BSMCs and BEAS-2B). Homozygotes for redefined haplotype h2 corresponding to minor alleles of SNP2 and SNP3 were associated with lower lung function in childhood-onset asthma patients compared to other zygotes (baseline Forced expiratory volume in one second (FEV1)/ Forced vital capacity (FVC) and Forced expiratory flow between 25% and 75% of the FVC (%FEF(25-75%)): P = 0.00201 and 0.0128, respectively, and post-bronchodilator FEV1/FVC and %FEF(25-75%): P = 0.00224 and 0.0393 respectively). Haplotype h2 was also associated with higher mRNA levels in control peripheral blood cells and higher blood eosinophil fractions and counts in female controls.

CONCLUSIONS AND CLINICAL RELEVANCE

Genetic variants were identified in the TBXA2R gene that influenced transcriptional activity and were associated with asthma-related phenotypes. Thromboxane pathways may therefore play important roles in airway inflammation and remodelling in asthma patients.

Involvement of endothelin-1 in habitual exercise-induced increase in arterial compliance

AIM

Habitual aerobic exercise results in a significant increase in central arterial compliance. Endothelin-1 (ET-1) is a potent endothelium-derived vasoconstrictor peptide and could play a role in mediating the habitual aerobic exercise-induced increase in central arterial compliance. The aim of the present study was to examine whether ET-1 is involved in the mechanisms underlying the increase in central arterial compliance with aerobic exercise training.

METHODS

Seven apparently healthy middle-aged and older (60 +/- 3 years) adults underwent systemic endothelin-A/B (ET(A/B))-receptor blockade (500 mg of Tracleer) before and after 12 weeks of aerobic exercise training (70 +/- 1% of maximal heart rate, 44 +/- 2 min day(-1), 4.4 +/- 0.1 days week(-1)).

RESULTS

Basal carotid arterial compliance (via simultaneous B-mode ultrasound and arterial applanation tonometry on the common carotid artery) increased significantly after exercise training. Resting plasma ET-1 concentration decreased significantly after exercise training. Before exercise intervention, carotid arterial compliance increased significantly with the administration of the ET(A/B)-receptor blockade. After training, however, increases in carotid arterial compliance previously observed with the ET(A/B)-receptor blockade before training were abolished.

CONCLUSIONS

Regular aerobic exercise training enhances central arterial compliance in middle-aged and older humans. The increase in arterial compliance was associated with the corresponding reduction in plasma ET-1 concentration as well as the elimination of ET-1-mediated vascular tone. These results suggest that reductions in ET-1 may be an important mechanism underlying the beneficial effect of exercise training on central artery compliance.

Differences in the composition of intestinal Bifidobacterium species and the development of allergic diseases in infants in rural Japan

BACKGROUND

Bifidobacterium is a dominant genus in the intestinal microbiota of infants and comprises many different species. A series of studies performed in northern Europe showed differences in the composition of Bifidobacterium species between allergic infants and healthy controls. Additional studies are needed to confirm this observation.

OBJECTIVE

To investigate the composition of fecal Bifidobacterium species in allergic infants and healthy controls in Japan, using molecular methods.

METHODS

Full-term born babies were followed up to 6 months of age at a local hospital in rural Japan. The presence or absence of allergy was determined based on allergic symptoms and skin prick tests. Fecal Bifidobacterium species in allergic infants (n=10), and healthy controls (n=16) were evaluated using nine Bifidobacterium species-specific or group-specific primers based on 16S rDNA sequences at 1, 3, and 6 months of age.

RESULTS

The number of the infants in whom no Bifidobacterium species could be found was four (15.4%) at 1 month, two (7.7%) at 3 months, and one (3.3%) at 6 months of age, all of whom were healthy controls. At 1 month of age, allergic infants had a higher prevalence f the Bifidobacterium catenulatum group than healthy controls (60.0% vs. 6.3%, P<0.01). At 6 months of age, allergic infants had a higher prevalence of B. bifidum than healthy controls (70.0% vs. 12.5%, P<0.01). These differences were not related to feeding method.

CONCLUSIONS

Our results in infants in rural Japan support the hypothesis that a compositional difference in intestinal Bifidobacterium species may be associated with the development of allergy in early infancy, although the responsible species might vary among countries or races.

Usefulness of magnetic resonance sialography in patients with juvenile Sjögren's syndrome

OBJECTIVE

Sialography is an important means for evaluating parotid gland damage in patients with Sjögren's syndrome (SS). However, 'conventional' X-ray sialography is invasive and sometimes difficult to perform and repeat, especially for young patients. Recently, magnetic resonance (MR) sialography has been used in adult SS patients. In this study, we investigated the usefulness of MR sialography for evaluating parotid gland damage in juvenile SS.

METHODS

Eight young patients suffering from SS were studied. MR sialography and X-ray sialography were performed simultaneously in the same patients. The images obtained by both methods were assessed with Rubin-Holt staging.

RESULTS

MR sialography detected ductal dilatation in 5 of 8 patients, while it was detected in 7 of 8 patients by X-ray sialography. The stages were the same in 4 patients by both methods. In 3 patients, the stages on X-ray sialography were higher than those on MR sialography; in 1 patient, the stage on MR sialography was higher. The correlation between the stages determined by the 2 methods was 0.85. There were no side effects in MR sialography, whereas 3 patients complained of pain during X-ray sialography.

CONCLUSION

MR sialography can evaluate Stage II approximately III parotid gland damage in juvenile SS. Although MR sialography cannot detect subtle changes in the duct, it has no side effects and can be performed repeatedly in young patients. We propose that MR sialography be chosen as the first tool for diagnosing and during follow-up of the status of the glands in juvenile SS.

Respiratory syncytial virus infection suppresses IFN-gamma production of gammadelta T cells

The immunological mechanisms by which respiratory syncytial virus (RSV) contributes to the development of asthma are poorly understood. gammadelta T cells are important in mucosal defence, and may contribute to the establishment of primary immune responses by producing cytokines early during respiratory infections. Thus, we used flow cytometry and intracellular cytokine staining to investigate the expression of interferon (IFN)-gamma and interleukin (IL)-4 by mitogen-stimulated gammadelta T cells from the peripheral blood of 15 hospitalized infants with RSV bronchiolitis, seven rotavirus-infected infants and eight normal controls. gammadelta T cells from RSV-infected infants had a lower proportion of IFN-gamma-producing cells (median, 4.00%; range, 0.58-6.60%) and a slightly but significantly higher proportion of IL-4-producing cells (median, 0.40%; range, 0.13-2.76%) than rotavirus-infected infants (median, 32.10%; range, 14.43-61.21%; P < 0.01, median, 0.00%; range, 0.00-0.00%; P < 0.05) in the acute phase. By contrast, differences in cytokine production by total CD3+ T cells did not differ significantly between patient groups. Thus, reduced IFN-gamma-production by gammadelta T cells in the peripheral blood of RSV-infected infants is accompanied by increased Th2 cytokine production during the acute phase of disease. At follow-up, eight children had recurrent episodes of wheezing. The frequencies of IFN-gamma-producing gammadelta T cells were significantly lower in patients who developed recurrent wheezing (median, 0.65%; range, 0.02-1.75%) than in patients without recurrent wheezing (median, 6.90%; range, 5.25-10.98%; P < 0.005). Cytokine production by gammadelta T cells may therefore be important in the pathogenesis of acute RSV disease, and play a part in the development of recurrent childhood wheezing after bronchilolitis.

Impairment of spermatogenesis in rats by methylmercury: involvement of stage- and cell- specific germ cell apoptosis

Methylmercury has been shown to affect the male reproductive organs. However, the specific mode of impairment of spermatogenesis during methylmercury exposure remains unknown. In this study, we characterized the induction of germ cell apoptosis and reproductive toxicity in Wistar male rats that had been exposed to methylmercuric chloride (MMC). Subcutaneous injection of MMC at a dose of 10 mg/kg per day for 8 days resulted in a 28% testicular weight loss at 14 days after the first injection. In addition, the ventral and dorso-lateral prostatic lobes showed a 65 and 52% decrease, respectively, at 14 days, although no effects were observed in the epididymis. Sperm production also was suppressed by the administration of MMC. After exposure to MMC, fragmentation of testicular DNA was found to be increased at 3 days after the first injection, with a 20-fold increase over control levels at 14 days. In situ detection of apoptosis by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labeling (TUNEL) staining revealed that spermatocytes and spermatids at stages VII-VIII and IX-XI, respectively, steps which are considered to be highly sensitive to testosterone, were the major cell types affected. Consequently, a marked cell loss in elongated spermatids at stages XII-XIV and I was observed at 14 days. In addition, plasma testosterone levels were reduced at 6 days after exposure to MMC, and remained at approximately 20% of control levels during the 14-day observation period. Our results suggest that methylmercury impairs spermatogenesis by germ cell deletion via cell- and stage- specific apoptosis.

Catecholamines and opioid peptides increase in plasma in humans during possession trances

Naturally induced possession trances have been observed in healthy people of many societies. The neurophysiological basis of this phenomenon remains unknown, however, because of the difficulty in accessing subjects in trances due to their sacred context. In the present study, we measured the plasma levels of several neuroactive substances from subjects exhibiting or lacking possession trance characteristics during Balinese dedicatory dramas under natural conditions. The trance group exhibited significant increases in plasma concentrations of noradrenaline, dopamine and beta-endorphin, compared with controls who performed the same actions as the trance group. The present finding suggests that catecholamines and opioid peptides are involved in possession trances.

Ozone exposure enhances expression of cell-surface molecules associated with antigen-presenting activity on bronchoalveolar lavage cells in rats

In this study, we investigated the effects of ozone (O3) exposure on expression of cell-surface molecules associated with antigen presentation and on accessory activity of bronchoalveolar lavage cells (BAL cells). Rats were exposed to 1 ppm O3 for 3 days. Expression of cell-surface molecules was measured by flow cytometry. Accessory activity of BAL cells was assessed by the allogeneic mixed lymphocyte reaction (MLR) and specific antigen-presenting activity. O3 exposure increased the expression of Ia, B7.1, B7.2, and CD11b/c on BAL cells. Morphological and immunological studies showed the Ia-positive cells to have monocyte-like features. Peripheral blood monocytes expressed Ia, B7.1, B7.2, and CD11b/c. The Ia expression on the monocytes was further increased by treatment of them with BAL fluid from O3-exposed rats (O3-BALF). Resident alveolar macrophages, however, did not express Ia antigen, and the Ia expression was not increased by O3-BALF. Neutrophils, which also infiltrated in response to O3 exposure, did not express Ia, B7.1, and B7.2. Therefore, infiltrating monocytes may have caused the increased expression of Ia and B7 molecules on BAL cells exposed to O3. The accessory activity of BAL cells in terms of MLR and specific antigen-presenting activity was also enhanced by O3 exposure. The present study suggests that monocytes infiltrating in response to O3 exposure caused enhancements of the expression of Ia and costimulatory molecules on and the accessory activity of BAL cells.

Exposure to ozone aggravates nasal allergy-like symptoms in guinea pigs

The ability of O3 exposure to aggravate ovalbumin (OVA)-induced nasal allergy-like symptoms was studied in guinea pigs. Guinea pigs were exposed to filtered air or to 0.4 ppm O3 for 5 weeks. During the exposure, 1% OVA or saline was administered into the nasal cavities once a week. Sneezes and nasal secretions were measured for a 20-min period following OVA administration. The number of eosinophils infiltrating both nasal epithelium and subepithelium and titers of specific anti-OVA-IgG were measured 24 h after the last administration. Ozone increased OVA-induced sneezing and nasal secretion, as well as induced nasal hyper-responsiveness to physical stimuli. The number of eosinophils infiltrating the nasal subepithelium was increased by O3, and the titer of anti-OVA-IgG tended to increase in the O3-exposed animals. Thus, exposure to O3 aggravated nasal allergy-like symptoms by inducing nasal hyper-responsiveness, the infiltration of eosinophils, and by tending to increase the production of anti-OVA-IgG.

Phenanthraquinone inhibits eNOS activity and suppresses vasorelaxation

Diesel exhaust particles cause an impairment of endothelium-dependent vasorelaxation and are associated with cardiopulmonary-related diseases and mortality, but the mechanistic details are poorly understood. Since we reported previously that phenanthraquinone, an environmental chemical contained in diesel exhaust particles, suppresses neuronal nitric oxide synthase (nNOS) activity by shunting electrons away from the normal catalytic pathway, it was hypothesized that phenanthraquinone inhibits endothelial NOS (eNOS) activity and affects vascular tone. Therefore, the effects of phenanthraquinone on eNOS activity, endothelium-dependent relaxation, and blood pressure were examined in the present study. Phenanthraquinone inhibited NO formation evaluated by citrulline formed by total membrane fraction of bovine aortic endothelial cells with an IC(50) value of 0.6 microM. A kinetic study revealed that phenanthraquinone is a competitive inhibitor with respect to NADPH and a noncompetitive inhibitor with respect to L-arginine. Endothelium-dependent relaxation of rat aortic rings by ACh was significantly inhibited by phenanthraquinone (5 microM), whereas the endothelium-independent relaxation by nitroglycerin was not. Furthermore, an intraperitoneal injection of phenanthraquinone (0.36 mmol/kg) to rats resulted in an elevation of blood pressure (1.4-fold, P < 0.01); under this condition, plasma levels of stable NO metabolites, nitrite/nitrate, in phenanthraquinone-treated rats was reduced to 68% of control levels. The present findings suggest that phenanthraquinone has a potent inhibitory action on eNOS activity via a similar mechanism reported for nNOS, thereby causing the suppression of NO-mediated vasorelaxation and elevation of blood pressure.

Graves' disease: a host defense mechanism gone awry

In this report we summarize evidence to support a model for the development of Graves' disease. The model suggests that Graves' disease is initiated by an insult to the thyrocyte in an individual with a normal immune system. The insult, infectious or otherwise, causes double strand DNA or RNA to enter the cytoplasm of the cell. This causes abnormal expression of major histocompatibility (MHC) class I as a dominant feature, but also aberrant expression of MHC class II, as well as changes in genes or gene products needed for the thyrocyte to become an antigen presenting cell (APC). These include increased expression of proteasome processing proteins (LMP2), transporters of antigen peptides (TAP), invariant chain (Ii), HLA-DM, and the co-stimulatory molecule, B7, as well as STAT and NF-kappaB activation. A critical factor in these changes is the loss of normal negative regulation of MHC class I, class II, and thyrotropin receptor (TSHR) gene expression, which is necessary to maintain self-tolerance during the normal changes in gene expression involved in hormonally-increased growth and function of the cell. Self-tolerance to the TSHR is maintained in normals because there is a population of CD8- cells which normally suppresses a population of CD4+ cells that can interact with the TSHR if thyrocytes become APCs. This is a host self-defense mechanism that we hypothesize leads to autoimmune disease in persons, for example, with a specific viral infection, a genetic predisposition, or even, possibly, a TSHR polymorphism. The model is suggested to be important to explain the development of other autoimmune diseases including systemic lupus or diabetes.

A novel mouse model of Graves' disease: implications for a role of aberrant MHC class II expression in its pathogenesis

Mice immunized with fibroblasts expressing an MHC class II molecule and human thyrotropin receptor (TSHR), but not either alone, develop major features characteristic of Graves' disease (GD), such as thyroid-stimulating autoantibodies directed against TSHR, increased serum thyroid hormone levels, and enlarged thyroid glands. The results indicate the need for the simultaneous expression of a class II molecule and the TSHR on the surface of the fibroblasts to develop stimulating anti-TSHR antibodies and full-blown GD in our model. A T cell line established from a mouse with hyperthyroidism proliferates in response to fibroblasts expressing a class II molecule and TSHR, but not to the fibroblasts expressing only TSHR, indicating that the class II molecules on the fibroblasts present TSHR-derived peptide(s) to T cells. These results strongly suggest that the acquisition of antigen-presenting ability by thyrocytes can lead to the induction or progression of GD. We identified a T cell epitope of TSHR by the proliferative response of spleen cells from mice immunized with fibroblasts expressing a class II molecule and TSHR to 80 overlapping peptides spanning the extracellular domain of human TSHR. The identification of a major T cell epitope provides an important clue to a novel therapy of GD.

Homing receptor expression on cord blood T lymphocytes and the development of atopic eczema in infants

Expression of the gut-homing receptor integrin alphaEbeta7, but not cutaneous lymphocyte-associated antigen (CLA), on milk allergen-stimulated cord blood T lymphocytes precedes the development of milk-induced eczema in early infancy. The data indicate the involvement of integrin alphaEbeta7 in the development of infantile allergic eczema and provide a clue to the avoidance of specific allergens and novel therapy targeting homing receptors in food allergy.

Intense exercise causes decrease in expression of both endothelial NO synthase and tissue NOx level in hearts

Cardiac myocytes produce nitric oxide (NO). We studied the effects of intense exercise on the expression of NO synthase (NOS) and the tissue level of nitrite (NO(2)(-))/nitrate (NO(3)(-)) (i.e., NOx), which are stable end products of NO in the heart. Rats ran on a treadmill for 45 min. Immediately after this exercise, the heart was quickly removed. Control rats remained at rest during the same 45-min period. The mRNA level of endothelial NOS (eNOS) in the heart was markedly lower in the exercised rats than in the control rats. Western blot analysis confirmed downregulation of eNOS protein in the heart after exercise. Tissue NOx level in the heart was significantly lower in the exercised rats than in the control rats. The present study revealed for the first time that production of NO in the heart is decreased by intense exercise. Because NO attenuates positive inotropic and chronotropic responses to beta(1)-adrenergic stimulation in the heart, the decrease in cardiac production of NO by intense exercise may contribute to the acceleration of increase in myocardial contractility and heart rate during intense exercise.

Zeta-crystallin catalyzes the reductive activation of 2,4,6-trinitrotoluene to generate reactive oxygen species: a proposed mechanism for the induction of cataracts

Exposure to 2,4,6-trinitrotoluene (TNT) has been shown to cause induction of cataract in which oxidative stress plays a critical role. From bovine lens we purified to homogeneity and identified an enzyme that catalyzes the reduction of TNT, resulting in the production of reactive oxygen species. The final preparation of TNT reductase showed a single band with a subunit molecular weight of 38 kDa on SDS-PAGE. Sequence data from peptides obtained by digestion with lysylendopeptidase Achromobacter protease I (API) revealed that TNT reductase is identical to zeta-crystallin. Superoxide anions were formed during reduction of TNT by zeta-crystallin, though negligible enzyme activity or protein content for superoxide dismutase, a superoxide scavenging enzyme, was found in the lens. Thus, the present results suggest that the induction of cataracts by TNT may be associated with increased oxidative stress, as a result of reductive activation of TNT generating superoxide anions, there being minimal antioxidant enzyme activity for defense against reactive oxygen species exogenously produced in the lens.

Enzyme activity and protein content of superoxide dismutase isozymes in human renal cell carcinoma

Alterations in renal superoxide dismutase (SOD) isozymes were examined in cancerous tissues of human renal cell carcinoma and the corresponding non-cancerous renal tissues. Cu,Zn-SOD activities in cancerous tissues were lower than those in normal tissues. Mn-SOD activities were varied in the cases examined, whereas no significant difference between cancerous and normal tissues was observed for Mn- or total-SOD activities. Immunoblot analysis showed that the loss in enzyme activity in cancerous tissue was greater than the decrease in protein content for either isozyme. The selective decrease in Cu,Zn-SOD activities in cancerous tissue observed in this study suggests that the cytoplasmic defense against free radical damage appears to be reduced in renal cell carcinoma.

Improved method for simultaneous determination of L-arginine and its mono- and dimethylated metabolites in biological samples by high-performance liquid chromatography

An improved method has been developed for the determination of L-arginine and its methylated metabolites, N(G)-monomethyl-L-arginine (L-NMMA), N(G),N(G)-dimethyl-L-arginine (asymmetric DMA, ADMA) and N(G),N(G)'-dimethyl-L-arginine (symmetric DMA, SDMA) in biological samples. Extraction of these compounds with a strong cation-exchange resin AG50W-X8 with L-homoarginine (2-amino-6-guanidinohexanoic acid) as an internal standard gave a recovery of more than 70% except for SDMA from plasma samples. After extracted samples were converted to fluorescent derivatives with o-phthalaldehyde (OPA) in an alkaline medium, the following high-performance liquid chromatographic separation with a ODS column (wide-pore size, 300 A) was successfully performed with an isocratic mobile phase system. The method permits quantitative determination of L-arginine and its methylated metabolites at concentrations as low as 4 microM and 0.18 microM, respectively. Using this method, the levels of L-arginine, L-NMMA, ADMA and SDMA in human plasma, urine and rat tissue were determined.

Decreased serum concentrations of nitric oxide metabolites among Chinese in an endemic area of chronic arsenic poisoning in inner Mongolia

Prolonged exposure to arsenic results in peripheral and cardiovascular manifestations, as does impaired production of endothelial nitric oxide (NO). In vitro studies have indicated that endothelial cells undergo damage by arsenic. However, no information has been available on the relationship between NO synthesis and chronic arsenic poisoning in humans. The present study was designed to reveal this question. The subjects were 33 habitants who continued to drink well water containing high concentrations of inorganic arsenic (mean value = 0.41 microg/ml) for about 18 years in Inner Mongolia, China, and 10 other people who lived in this area but exposed to minimal concentrations of arsenic (mean value = 0.02 microg/ml) were employed as controls. Mean blood concentration of total arsenic was six times higher in exposed subjects than controls; 42.1 vs. 7.3 ng/ml, p <.001. Mean serum concentration of nitrite/nitrate, stable metabolites of endogenous NO, was lower in arsenic-exposed subjects than in controls: 24.7 vs. 51.6 microM, p<.001. In total samples, an inverse correlation with serum nitrite/nitrate levels was strong for blood inorganic arsenic (r = -0.52, p <.001) and less strong for its metabolites, monomethyl arsenic (r = -0.45, p<.005) and dimethyl arsenic (r = -0.37, p<.05). Furthermore, serum nitrite/nitrate concentration was significantly correlated with nonprotein sulfhydryl level in whole blood (r = 0.58, p<.001). In an in vitro study, we demonstrated that inorganic arsenite or arsenate suppresses the activity of endothelial NO synthase in human umbilical vein endothelial cells. These results suggest that long-term exposure to arsenic by drinking well water possibly reduces NO production in endothelial cells, resulting in a decrease in reduced nitrite/nitrate concentrations. Peripheral vascular disorders caused by arsenic may be attributable in part to impairment of NO production in vivo.

Involvement of granzyme B expression in the enhancement of natural killer activity by beta-endorphin

Beta-Endorphin has been reported to enhance natural killer (NK) activity in vitro. However, few studies have examined the precise regulation of the cytolytic stage of NK cells. We therefore investigated the regulation by beta-endorphin of cytotoxicity-associated molecules such as granzyme B, perforin, and Fas ligand (FasL) in human CD16(+) NK cells. On semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) assay, the granzyme B mRNA level apparently increased in CD16(+) NK cells from high responding subjects having ratios >1.5 for the LU(30) ratio. An increase in intracellular granzyme B molecules was also detected in CD16(+) NK cells by flow cytometry. On the other hand, perforin and FasL appeared not to be involved in regulation by beta-endorphin. These findings suggest that up-regulation of granzyme B expression may be involved in the enhancement of NK activity by beta-endorphin.

Circadian variation in nasal reactivity in children with allergic rhinitis: correlation with the activity of eosinophils and basophilic cells

BACKGROUND

In allergic rhinitis, the major symptoms of runny nose, sneezing, and stuffy nose tend to become worse upon waking up in the morning, and yet the mechanisms underlying this phenomenon are poorly understood. We investigated whether the worsening of allergic rhinitis in the morning is associated with changes in the activity of inflammatory cells.

METHODS

Nasal reactivity to methacholine was assessed twice in 8 children with allergic rhinitis and 8 healthy control subjects at 6.00 a.m. and 3.00 p.m. The amounts of eosinophil cationic protein (ECP), histamine and tryptase in induced nasal secretions and peripheral blood were also measured.

RESULTS

Nasal reactivity to methacholine was higher at 6.00 a.m. not only in patients but also in healthy controls. Serum ECP and plasma histamine levels showed no circadian patterns. On the other hand, significantly higher levels of inflammatory activation products were found in nasal secretions at 6.00 a.m., thus showing a direct association with nasal reactivity.

CONCLUSION

These results suggest that the circadian variation in nasal reactivity is associated with changes in the activity of eosinophils and basophilic cells in the nasal mucosa.

Selective induction of apoptosis of renal proximal tubular cells caused by inorganic mercury in vivo

A recent notion, that a variety of toxicants causing necrosis can lead to apoptosis as well, has been demonstrated with cultured cells, but not with in an vivo system. In the present study, we examined the induction of both apoptosis and necrosis in the kidneys of Wistar rats exposed to mercuric chloride (HgCl(2)). A single injection of HgCl(2) to rats at a dose of 4 mg/kg resulted in an increase in the renal DNA fragmentation evaluated as an occurrence of apoptosis, prior to urinary excretion of alkaline phosphatase (ALP) and renal morphological changes assessed as necrotic phenomena. The mercury-promoted DNA fragmentation was induced in a dose-dependent manner. Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining and morphological observation of the nuclei revealed that apoptotic cells caused by HgCl(2) were predominantly found in the proximal tubules, but not in the distal tubules, glomeruli or medullary tubules. When we confirmed the proximal tubular-selective apoptosis by inorganic mercury with a combined technique of TUNEL staining with synchrotron radiation X-ray fluorescence (SR-XRF) imaging, it was shown that the apoptotic cells localized in the proximal tubules did contain higher level of mercury. Thus these results indicate that the proximal tubular cells-dominant site-specific distribution of mercury appears to be associated with induction of renal apoptosis and necrosis.

A new boronated porphyrin (STA-BX909) for neutron capture therapy: an in vitro survival assay and in vivo tissue uptake study

A new boronated porphyrin compound (STA-BX909) was developed as a possible agent for boron neutron capture therapy. The boron concentration was measured by an in vivo rat experimental brain tumor model and an in vitro cell culture study. This agent was compared to sodium borocaptate (BSH) which has been used in clinical trials of boron neutron capture therapy. In the 9L rat brain tumor model, STA-BX909 achieved a higher boron tumor/blood ratio 24 h after injection in comparison to BSH. A boron concentration study in cultured glioma cell lines (U-251, U-87, 9L) demonstrated an increased boron concentration as a function of exposure time to STA-BX909, while the boron concentration remained stable with increasing exposure time to BSH. Use of a colony forming assay with thermal neutron irradiation revealed more cytotoxicity with STA-BX909 than BSH when the same concentration of 10B was administered. We concluded that STA-BX909 may be an effective drug for use in boron neutron capture therapy and that it merits further investigation.

Inhibition of nitric oxide formation and superoxide generation during reduction of LY83583 by neuronal nitric oxide synthase

6-Anilino-5,8-quinolinedione (LY83583) has been widely used as an agent to reduce levels of nitric oxide (NO)-dependent cGMP in tissues. We report here that suppression of NO formation and production of superoxide during enzymatic reduction of LY83583 by neuronal NO synthase appeared to be potentially involved in the pharmacological action caused by LY83583. LY83583 suppressed neuronal NO synthase activity of 20,000 x g rat cerebellar supernatant preparation in a concentration-dependent manner (IC50 value = 12.9 microM). A kinetic study revealed that LY83583 is a competitive inhibitor with respect to NADPH, with a Ki value of 2.57 microM. With purified neuronal NO synthase it was found that LY83583 was a potent inhibitor of NO formation by the enzyme and served as efficient substrate for reduction with a specific activity of 173 nmol of NADPH oxidized per mg of protein per minute. The reductase activity was stimulated about 19.8-fold by addition of CaCl2/calmodulin, indicating that the presence of CaCl2/calmodulin is essential to express maximal activity of LY83583 reduction. Although LY83583 was a good substrate for both NADPH-cytochrome P450 reductase (P450 reductase) and DT-diaphorase, these flavin enzymes-catalyzed reductions of LY83583 were less than the neuronal NO synthase-mediated reduction in the presence of CaCl2/calmodulin. Enzymatic generation of superoxide during reduction of LY83583 by neuronal NO synthase, P450 reductase or DT-diaphorase was confirmed by electron spin resonance (ESR) experiments. Thus the present results indicate that a benzoquinone derivative LY83583 appears to interact with the P450 reductase domain on neuronal NO synthase, resulting in inhibition of NO formation and superoxide generation, which is involved in suppression of intracellular cGMP content.

Serum antioxidant vitamins and risk of lung and stomach cancers in Shenyang, China

In a hospital-based case control study, we measured serum concentrations of vitamin A, beta-carotene and vitamin E for subjects with cancer (58 cases of lung cancer and 22 cases of stomach cancer) and 63 matched controls in Shenyang, China. Lung cancer patients had significantly (P < 0.01) lower mean serum levels of vitamin A, beta-carotene and vitamin E than controls, while the mean serum level of vitamin E did not differ between stomach cancer patients and the controls. Lower serum levels of vitamin A, vitamin E and beta-carotene were associated with an increased risk of lung cancer. Lower serum levels of vitamin A and beta-carotene were associated with a higher risk of stomach cancer, although the number of cases was small. An increased risk of lung cancer associated with lower serum levels of vitamin A and vitamin E was more evident among heavy smokers than among non-heavy smokers.

Differential changes in rat brain nitric oxide synthase in vivo and in vitro by methylmercury

Alterations in mRNA level, protein content and enzyme activity for nitric oxide synthase (NOS) in the cerebrum and cerebellum during a continuous exposure of neurotoxic metal, methylmercury, were examined in Wistar rats. Subcutaneous (s.c.) administration of methylmercuric chloride (MMC, 10 mg kg-1 day-1, 8 days) resulted in significant increases with time of NOS activities in the cerebrum (1. 6-1.9-fold, 5-8 days) and cerebellum (1.4-fold, 8 days). RT-PCR and immunoblot analyses indicated that the increase in the enzyme activity caused by this metal appears to be due to increase in protein levels of neuronal NOS (nNOS), but not inducible NOS (iNOS) because little appreciable mRNA and protein for iNOS were seen during MMC exposure. The direct effect of mercuric compounds on nNOS activity in vitro was evaluated using 20,000xg supernatant from rat cerebellum homogenate. In contrast to the in vivo observation, inorganic-, alkyl-, and aryl-mercuric compound showed potent inhibition of nNOS activity with IC50 values of 11-43 microM, whereas dimethylmercury (DMM) was without effect on the enzyme activity. Further experiments indicated that the inhibition of nNOS by organomercurial occurred via thiol modification.

Inhibition of nitric oxide formation by neuronal nitric oxide synthase by quinones: nitric oxide synthase as a quinone reductase

Inhibitory action of a variety of quinoid compounds on neuronal nitric oxide synthase (nNOS) activity was examined with a 20000g rat cerebellar supernatant preparation and purified nNOS. The inhibition of citrulline formation from l-arginine by quinones, which exhibit one-electron reduction potentials (E17) ranging between -240 and -100 mV, increased at a more positive one-electron reduction potential, suggesting that quinone appears to act as an electron acceptor for nNOS. Among the quinones tested, 9,10-phenanthraquinone (PQ), corresponding to an E17 value of -124 mV, exhibited the most potent inhibiton of citrulline formation (IC50 value = 10 microM). A kinetic study revealed that PQ is a competitive inhibitor with respect to NADPH, with a Ki value of 0.38 +/- 0.12 microM, and a noncompetitive inhibitor with respect to l-arginine, with a Ki value of 9.63 +/- 0.20 microM. Partial purification of the enzymes which are responsible for reducing PQ in 20000g supernatant of rat cerebellum by anion-exchange column chromatography indicated that one catalyst for PQ reduction was nNOS. Reductase activity of PQ by purified nNOS required CaCl2/calmodulin and was markedly suppressed by the flavoprotein inhibitor diphenyleneiodonium but not by l-nitroarginine which is a specific inhibitor for NO formation. nNOS effectively reduced the quinones as well as PQ causing a marked decrease in the production of NO from l-arginine, while 1, 4-benzoquinone, 9,10-anthraquinone, mitomycin C, and lapachol, which show negligible inhibitory action on nNOS activity, were poor substrates for the enzyme on reduction. These results indicate that PQ and other quinones used in the present study interact with the NADPH-cytochrome P450 reductase domain on nNOS and thus probably inhibit NO formation by shunting electrons away from the normal catalytic pathway. Therefore, our study suggests that quinones could possibly affect NO-dependent physiological and/or pathophysiological actions in vivo.

Determinant analysis of IgE and IgG4 antibodies and T cells specific for bovine alpha(s)1-casein from the same patients allergic to cow's milk: existence of alpha(s)1-casein-specific B cells and T cells characteristic in cow's-milk allergy

In an effort to clarify the etiology of milk allergy from the standpoint of allergen-specific immune reactions, we investigated the determinants of IgE, IgG4, and T cells specific for bovine alpha(s)1-casein from the same individual patients by using its synthetic peptides and cyanogen bromide-digested fragments. Alpha(s)1-casein is a major allergen in cow's milk, and its unique conformation enabled us to investigate the determinants of antibodies without consideration about missing the reactivities because of conformational changes. Nine patients were selected as subjects from among 129 milk-sensitive infants screened by ELISA to assess the anti-alpha(s)1-casein IgE levels in their sera. By using ELISA for epitope mapping, a C-terminal region of alpha(s)1-casein was identified as a common binding site for IgE from all of these patients, whereas those for anti-alpha(s)1-casein IgG4 were located in multiple regions of alpha(s)1-casein. We determined the specificities of seven alpha(s)1-casein-specific T-cell lines established from peripheral blood mononuclear cells of two of the patients. These T cells have been shown to secrete IL-4. All of the T-cell lines had different specificities to alpha(s)1-casein. However, a common amino acid residue use was found among the determinants of various T-cell lines from each patient. The results suggest that patients allergic to cow's milk have characteristic B cells recognizing a limited region of alpha(s)1-casein and secreting alpha(s)1-casein-specific IgE. These B cells may interact particularly with T cells recognizing determinants with a common structure.

[Allergen-induced cytokine messenger RNA expression of peripheral blood mononuclear cells in active and remission of food allergy]

Substantial part of patients who suffer from food allergy outgrow their allergic reaction. Moreover the mechanisms of this phenomenon are poorly understood. We studied cytokine mRNA expression in peripheral blood mononuclear cells (PBMC) from children with egg allergy, nine patients on active stage and eight were outgrown, and four healthy controls, by use of reverse transcription polymerase chain reaction. Following ovalbumin (OVA) stimulation in vitro, active patients demonstrated increasing IL-5 mRNA. In comparison, no increasing expression of IL-5 mRNA was observed in outgrown and healthy children. IL-4 and IFN-gamma mRNA expression has no tendency either to increase or to decrease in all three groups. There was no difference of proliferative responses for OVA among these groups suggesting that outgrown patients' PBMC did not fall into anergy or clonal deletion. These data suggested the change in balance of cytokine production of PBMC which were stimulated by allergen is a trigger for "outgrow" of food allergy.

The formation of thyrotropin receptor (TSHR) antibodies in a Graves' animal model requires the N-terminal segment of the TSHR extracellular domain

Immunization of AKR/N mice with murine fibroblasts, transfected with the TSH receptor (TSHR) and a murine major histocompatibility complex class II molecule having the same H-2k haplotype (but not either alone), induces immune thyroid disease with the humoral and histological features of human Graves', including the presence of two different TSHR antibodies (TSHRAbs): stimulating TSHRAbs, which cause hyperthyroidism; and TSH-binding-inhibiting immunoglobulins. The primary functional epitope for both types of antibodies in Graves' patients is on the N-terminal portion of the extracellular domain of the TSHR, residues 25 to 165; most require residues 90-165 to express TSHRAb activity, as evidenced in studies using chimeras of the TSHR and lutropin-choriogonadotropin receptor (LH-CGR). To evaluate the role of this region of the TSHR in the formation of Graves' TSHRAbs, we immunized AKR/N mice with fibroblasts transfected with three human TSHR chimeras with residues 9-165 (Mc1+2), 90-165 (Mc2), or 261-370 (Mc4) substituted by equivalent residues of the rat LH-CGR. Mice immunized with the Mc1+2 and Mc2 chimeras, with the N-terminal portion of the extracellular domain of the TSHR substituted by LH-CGR residues, did not develop TSHRAbs. Mice immunized with the Mc4 chimera, having a major portion of the C-terminal portion of the extracellular domain of the TSHR replaced by comparable LH-CGR residues, can develop TSHRAbs. The results suggest that the N-terminal segment of the TSHR extracellular domain is not only a critical functional epitope for Graves' TSHRAbs, but it is important also in their formation in a mouse model of Graves' disease.

Murine strain differences in airway inflammation caused by diesel exhaust particles

To elucidate whether immunoglobulin (Ig) E or IgG are involved in the murine asthma model, we compared the pathogenic features of mice that were high IgG responders (C3H/He) with mice that were high IgE responders (BALB/c) after intratracheal instillation of diesel exhaust particles (DEP) and ovalbumin sensitization. Both mouse strains received DEP intratracheally once a week for 5 weeks. After the second injection of DEP, ovalbumin and aluminium hydroxide were injected intraperitoneally. After the last DEP administration, the mice were challenged by exposure to an aerosol of ovalbumin. DEP caused increased IgG1 production and airway hyperresponsiveness after ovalbumin sensitization in C3H/He mice, although IgE production did not change in either strain. Furthermore, in C3H/He mice, the number of eosinophils and goblet cells in the bronchial epithelium, and the expression of interleukin-5 and interleukin-2 were increased by DEP and ovalbumin treatments. In contrast, the pathogenic changes in BALB/c mice were weak, even though the same protocol was used. In conclusion, murine strain differences in response to air pollutants and allergens seem to be related to antigen-specific immunoglobulin G1 production and cytokine expression in the lungs.

Lactate and acid-base balance at delivery in relation to cardiotocography and T/QRS ratios in the second stage of labour

OBJECTIVE

To compare foetal electrocardiogram (T/QRS ratio) and cardiotocography (CTG) during the second stage of labour with lactate and acid-base balance in cord artery blood at delivery.

DESIGN

Forty-six parturients delivered at the National University of Singapore were monitored during the second stage of labour with T/QRS ratios and CTG. At delivery blood from a segment of clamped cord was sampled for lactate and acid-base balance analyses. The Spearman Rank correlation, the Mann Whitney U-test and the Kruskal Wallis ANOVA were used when appropriate.

RESULTS

Maternal pushing time was significantly correlated to lactate (R = 0.51; P = 0.0003), pH (R = -0.38; P = 0.009) and base deficit (R = 0.33; P = 0.026), but not to T/QRS ratio (R = 0.002; P = 0.99). No significant correlation between lactate and T/QRS ratios (R = 0.06; P = 0.70) or type of CTG pattern was found (P = 0.10), though there were significant differences in pH (P = 0.029) and T/QRS ratios (P = 0.037) between groups with different FHR abnormalities.

CONCLUSION

Lactate increases progressively with maternal pushing time. No significant correlation was found between lactate and the T/QRS ratio. Lack of correlation is likely to be due to poor sensitivity of foetal ECG at this level of foetal stress, though the influence from transplacentally transferred maternal lactate cannot be excluded.