Sarcopenia, the depletion of muscle mass, an independent predictor of respiratory complications after oncological esophagectomy.

Surgery for esophageal carcinoma is known to be associated with high morbidity. Recent studies have reported a correlation of nutritional and inflammatory parameters with postoperative course. This study aims to clarify the risk factors for operative morbidity after resection of esophageal carcinoma. Consecutive patients who underwent esophagectomy for esophageal squamous cell carcinoma at our institute were included (n = 102; 89 males and 13 females; mean age: 67.3 years). Clinicopathological characteristics, presence or absence of sarcopenia, and modified Glasgow prognostic score were assessed, and their correlation with postoperative complications was investigated using univariate and multivariate analyses. Sarcopenia was defined using a combination of muscle mass area and body mass index. Of the included 102 patients, 45 (44.1%) exhibited sarcopenia (sarcopenia group), while 57 (55.9%) did not (non-sarcopenia group). No significant difference was observed between the groups regarding surgical procedures and tumor stage; furthermore, there was no mortality. Twenty-six patients developed respiratory complications (including 20 cases of pneumonia). On univariate analysis, sarcopenia, modified Glasgow prognostic score, and American Society of Anesthesiologists physical status were found to be significantly associated with the development of postoperative respiratory complications. On multivariate analysis, sarcopenia was found to be an independent risk factor for postoperative respiratory complications after esophagectomy. We believe that identifying patients at risk and providing preoperative nutritional support as well as physical therapy aimed at strengthening of body muscles may help reduce the incidence of postoperative respiratory complications in such patients.

Endoscopic evaluation of food bolus formation and its relationship with the number of chewing cycles.

It is known that solid food is transported to the pharynx actively in parallel to it being crushed by chewing and mixed with saliva in the oral cavity. Therefore, food bolus formation should be considered to take place from the oral cavity to the pharynx. In previous studies, the chewed food was evaluated after the food had been removed from the oral cavity. However, it has been pointed out that spitting food out of the oral cavity interferes with natural food bolus formation. Therefore, we observed food boluses immediately before swallowing using an endoscope to establish a method to evaluate the food bolus-forming function, and simultaneously performed endoscopic evaluation of food bolus formation and its relationship with the number of chewing cycles. The subject was inserted the endoscope nasally and instructed to eat two coloured samples of boiled rice simultaneously in two ingestion conditions ('as usual' and 'chewing well'). The condition of the food bolus was graded into three categories for each item of grinding, mixing and aggregation and scored 2, 1 and 0. The score of aggregation was high under both ingestion conditions. The scores of grinding and mixing tended to be higher in subjects with a high number of chewing cycles, and the score of aggregation was high regardless of the number of chewing cycles. It was suggested that food has to be aggregated, even though the number of chewing cycles is low and the food is not ground or mixed for a food bolus to reach the swallowing threshold.

Swallowing frequency in elderly people during daily life.

Disuse atrophy of swallowing-related organs due to an excessive decrease in swallowing frequency is suspected to occur in patients with poor oral intake, especially elderly people. However, swallowing frequency in daily life has not previously been examined in the elderly. This study examined swallowing frequency in elderly people and compared these findings to those in a younger population and differences in the degree of activity in daily life. (i) We compared swallowing frequency in 20 elderly people (82·0 ± 8·3 year) and 15 healthy young people (26·5 ± 3·5 year). (ii) 20 elderly people were divided into two groups according to the degree of activity in daily life: a semi-bedridden group and bedridden group; the swallowing frequency was compared between these groups. (i) The swallowing frequency in the elderly people was 2-19 times per hour and the mean was 9·4 ± 4·9, and that in the healthy young people was 16-76 times per hour and the mean was 40·7 ± 19·5. Swallowing frequency in elderly people was significantly lower than that in young healthy people (P < 0·0001). (ii) The swallowing frequency in bedridden group was 2-11 times per hour and the mean was 6·8 ± 3·3, and that in semi-bedridden group was 3-19 times per hour and the mean was 11·9 ± 5·1. Swallowing frequency in bedridden group was significantly lower than that in semi-bedridden group (P < 0·05). These results indicate that in daily life, elderly people tend to swallow less frequently than young people. In addition, swallowing frequency was lower in elderly subjects with a low degree of activity in daily life.

Effects of the bolus volume on hyoid movements in normal individuals.

The hyoid bone moves during swallowing due to contraction of suprahyoid muscles, which are critical components of normal swallowing function. It has been reported that the muscle force and shortening velocity decline gradually with age. Reduced hyoid velocities may delay the sealing of the laryngeal vestibule and opening of the cricopharyngeal muscle. We hypothesised that the hyoid velocity could be a factor influencing aspiration. This study evaluated effects of bolus volume changes on the hyoid distance and velocity in normal swallowing. The subjects were 21 healthy young adults. Lateral projection videofluorography was recorded while each subject swallowed 2·5, 5·0, 10 and 20 mL of liquid barium. We evaluated the maximum hyoid distance (Max d), anterior and superior distance (Max ad, Max sd). And, we evaluated the maximum velocity (Max v), anterior and superior velocity (Max av, Max sv). Two-way anova test revealed that Max d, Max ad and Max sd for different bolus volumes are not significantly different. But, two-way anova test showed statistically significant difference in Max v, Max av and Max sv among different bolus volume (P < 0·01). Tukey's test showed that there are significant differences in Max v between 2·5 and 20 mL, 5·0 and 20 mL, 10 and 20 mL, and 2·5 and 10 mL swallowing. And, Tukey's test showed significant differences in Max av and Max sv between 2·5 and 20 mL, 5·0 and 20 mL, and 10 and 20 mL swallowing. It is possible that a larger bolus volume requires greater maximum hyoid velocity. We plan to study hyoid velocity in elderly subjects and in those with dysphagia.

Clinical application of endoscopic soft palate augmentation in the treatment of velopharyngeal insufficiency.

Velopharyngeal structure augmentation with the injection of autologous fat tissue into the nasal mucosa of the soft palate has been reported previously. However, as the injection points in the velopharyngeal space cannot be observed directly, these injections may be difficult to perform accurately. This report describes a new endoscope-assisted approach in which the materials for velopharyngeal structure augmentation are administered while observing the injection points directly, also enabling adjustment of the amount of material injected. A case series of five patients aged 8-16 years who underwent endoscopic soft palate augmentation under general anaesthesia is reported. Autologous fat tissue was injected into the nasal mucosa of the soft palate using a needle-type device of an endoscope, and the effects of the treatment were evaluated. The injections were performed successfully, and the velopharyngeal function was improved. This new technique of endoscopy-assisted augmentation was useful for the treatment of velopharyngeal insufficiency.

Development of a swallowing frequency meter using a laryngeal microphone.

Disuse atrophy of swallowing-related organs is suspected when decreased swallowing frequency is seen in the elderly. However, swallowing frequency has not been examined in elderly people during daily life. We developed a swallowing frequency meter containing a laryngeal microphone that does not restrict the subject's ability to perform daily activities. In this study, the utility of the meter was assessed. Experiment 1: The ability of the meter to detect swallowing was examined. The subject was instructed to swallow saliva or foods at a voluntarily pace. During these procedures, swallowing events were simultaneously recorded by the meter, self-enumeration and videofluorography. As a result, all of the swallowing events identified by the meter coincided with the swallowing events identified by self-enumeration and videofluorography. Experiment 2: Swallowing sounds display various patterns both between and within individuals. Therefore, we examined the concordance rate between the number of swallowing events counted by the meter and that counted by self-enumeration in 15 subjects over a longer period than in experiment 1. The concordance rates calculated by two examiners between the meter and self-enumeration were 96·8 ± 4·5% and 98·9 ± 3·3% at rest and 95·2 ± 4·5% and 96·1 ± 4·1% during meals, respectively. Our findings indicate that this meter is useful for measuring the frequency of swallowing during daily situations.

Influence of Olfactory Function on Appetite and Nutritional Status in the Elderly Requiring Nursing Care.

OBJECTIVE: To investigate olfactory function in elderly subjects requiring nursing care to clarify its association with appetite and nutritional status. SETTING: Facility for the elderly requiring nursing care. PARTICIPANTS: The subjects were 158 elderly people requiring nursing care and 37 elderly people not requiring nursing care. MEASUREMENTS: Experiment I: Olfactory function and factors (cognitive function, appetite, and nutritional status) that may be associated with it were compared between the elderly subjects requiring nursing care and those not requiring nursing care using covariance analysis in consideration of age. For evaluation, the OSIT-J was used for olfactory function, the HDS-R for cognitive function, the CNAQ for appetite, and BMI for nutritional status. Experiment II: The subjects were the same elderly subjects requiring nursing care in Experiment I, and food intake was surveyed in addition to the OSIT-J, HDS-R, CNAQ, and BMI. A univariate linear regression analysis was performed with OSIT-J as the response variable, and age, HDS-R, CNAQ, BMI, and food intake as the explanatory variables. RESULTS: Experiment I: On covariance analysis, the OSIT-J score was significantly lower for the elderly subjects requiring nursing care than for those not requiring nursing care (p<0.01). The mean score was 8 or lower in both groups, demonstrating lower olfactory function in both groups. Regarding factors that may be associated with olfactory function, a significant difference was noted in the HDS-R (p<0.01), confirming significantly lower cognitive function in the elderly subjects requiring nursing care. No significant difference was noted in the CNAQ or BMI. Experiment II: On a univariate linear regression analysis, an association with the OSIT-J was noted for age and HDS-R. Age was inversely correlated and the HDS-R was positively correlated. Factors associated with lower olfactory function in the elderly subjects requiring nursing were age and cognitive function, whereas appetite, nutritional status, and food intake were not associated. CONCLUSION: Olfactory function in elderly subjects requiring nursing care was poorer than that in those not requiring nursing care, suggesting that aging and cognitive decline are associated with lower olfactory function. In addition, no association of lower olfactory function with appetite, nutritional status, or food intake was noted in the elderly subjects requiring nursing care.

Epigenetics as a mechanism linking developmental exposures to long-term toxicity.

A variety of experimental and epidemiological studies lend support to the Developmental Origin of Health and Disease (DOHaD) concept. Yet, the actual mechanisms accounting for mid- and long-term effects of early-life exposures remain unclear. Epigenetic alterations such as changes in DNA methylation, histone modifications and the expression of certain RNAs have been suggested as possible mediators of long-term health effects of environmental stressors. This report captures discussions and conclusions debated during the last Prenatal Programming and Toxicity meeting held in Japan. Its first aim is to propose a number of criteria that are critical to support the primary contribution of epigenetics in DOHaD and intergenerational transmission of environmental stressors effects. The main criteria are the full characterization of the stressors, the actual window of exposure, the target tissue and function, the specificity of the epigenetic changes and the biological plausibility of the linkage between those changes and health outcomes. The second aim is to discuss long-term effects of a number of stressors such as smoking, air pollution and endocrine disruptors in order to identify the arguments supporting the involvement of an epigenetic mechanism. Based on the developed criteria, missing evidence and suggestions for future research will be identified. The third aim is to critically analyze the evidence supporting the involvement of epigenetic mechanisms in intergenerational and transgenerational effects of environmental exposure and to particularly discuss the role of placenta and sperm. While the article is not a systematic review and is not meant to be exhaustive, it critically assesses the contribution of epigenetics in the long-term effects of environmental exposures as well as provides insight for future research.

2-(7,13-Dihydroxy-2-trans-octadecenoylamino)ethanesulfonic acid (lipotaurine) as an intermediate of taurolipids biosynthesis.

A hydroxy fatty-acid-combined taurine (lipotaurine) was found in the taurolipids fraction of Tetrahymena thermophila. Lipotaurine accounted for about 1.4% of the total taurolipids of the cells, and was composed of taurine and 7,13-dihydroxy-2-trans-octadecenoic acid. By nuclear magnetic resonance, mass and infrared spectrometries, the chemical structure of lipotaurine was identified as 2-(7,13-dihydroxy-2-trans-octadecenoylamino)ethanesulfonic acid. When cells of T. thermophila were incubated with the double-labeled lipotaurine which was biosynthesized from [2(n)-3H]taurine and [1-14C]stearic acid, both the radioactivities were detected in taurolipid A, B and C. Furthermore, the ratio of the radioactivities of 3H and 14C in the lysotaurolipids were the same as that of the lipotaurine. From these results, it is suggested that lipotaurine is an intermediate of taurolipid biosynthesis.

Gangliosides involved in activation of rat T lineage cells.

Gangliosides have long been known to be involved in T-cell activation. In our previous studies, a unique GMlb-derived ganglioside, GD1c(NeuGc,NeuGc), was shown to be the predominant ganglioside in rat thymocytes and T-cells. Upon the activation of the thymocytes, the amount of GD1c(NeuGc,NeuGc) increases remarkably, and additionally a novel species of GD1b, GD1b(NeuGc,NeuGc), appears as the other major ganglioside (Nohara, et al. (1993) J. Biol. Chem. 268, 24997-25000). In the present study, monoclonal antibodies (MAbs) against these two gangliosides have been generated. The MAb AC1 established by immunizing mice with purified GD1c(NeuGc,NeuGc) reacted strongly with GD1c(NeuGc,NeuGc) and weakly with GD1b(NeuGc,NeuGc) by enzyme-linked immunosorbent assay (ELISA). The other MAb AB1 obtained by immunization with GD1b(NeuGc,NeuGc) showed a strong binding activity to GD1b(NeuGc,NeuGc) and no reactivity to GDlc(NeuGc,NeuGc) by ELISA. Flow cytometry analyses using these MAbs have revealed that an AC1-positive subset exists in a portion of resting CD4+CD8- thymocytes and CD4+ splenic T-cells. When the thymocytes were activated with 12-O-tetradecanoylpholbol-13-acetate (TPA) and calcium ionophore A23187, the proportion of AC1+ cells increased remarkably and were detected not only in CD4+ cells but also in CD8+ cells. An increase in the proportion of AC1+ cells was also seen in activated T-cells. In contrast, AB1-positive cells were only detected in activated thymocytes, not in resting thymocytes, or resting or activated T-cells. These results implicate GD1c(NeuGc,NeuGc) in the activation of thymocytes as well as T-cells, whereas GD1b(NeuGc,NeuGc) appears to be specifically related to the activation of thymocytes.

Antibody against ganglioside GD1c containing NeuGcalpha2-8NeuGc cooperates with CD3 and CD4 in rat T cell activation.

Gangliosides have long been implicated in T cell activation. GD1c with two N-glycolylneuraminic acids [GD1c(NeuGc,NeuGc)] is the predominant ganglioside in rat T cells. In the present study, the anti-GD1c(NeuGc,NeuGc) mAb, AC1, which binds to the NeuGcalpha2-8NeuGcalpha2- sequence, was found to enhance Con A-activated cellular proliferation at a concentration at which AC1 alone did not activate the cells. The potentiation by AC1 was observed more consistently and effectively in the cellular activation elicited by cross-linking of anti-CD3 and anti-CD4, rather than in the cell growth induced by immobilized anti-CD3 alone. Moreover, the combination of immobilized anti-CD4 and soluble AC1 had a remarkable mitogenic effect. In addition, we have demonstrated the existence of a 100 kDa protein in rat T cell lysates which reacts with AC1 on Western blots, and this interaction is abolished by sialidase-treatment of the membrane. Pronase treatment of the T cells, which rendered the 100 kDa protein undetectable on Western-blotting, reduced the number of AC1-positive cells by 40-50% on flow cytometry. On the other hand, all cells became AC1-negative after sialidase treatment. These findings indicated that AC1 reacts with both GD1c(NeuGc,NeuGc) and the 100 kDa glycoprotein on rat T cells. Taken together, these results predict the presence of a novel regulatory mechanism of T cell activation involving CD4 and the NeuGcalpha2-8NeuGcalpha2- sequence.

A GM1b-derived disialoganglioside GD1c is the predominant ganglioside of rat thymocytes.

The thin-layer chromatographic (TLC) pattern of gangliosides of rat thymocytes showed a profile characterized by the occurrence of a predominant ganglioside which did not correspond to any reference gangliosides of rat brain. The ganglioside was isolated from rat thymus, and characterized by compositional analysis, methylation analysis, sialidase treatment, negative-ion fast atom bombardment (FAB) mass spectrometry, and proton NMR spectroscopy. The structure was elucidated to be NeuGc alpha 2-8NeuGc alpha 2-3Gal beta 1-3GalNac beta 1-4Gal beta 1-4Glc beta 1-1Cer. This is the major ganglioside of rat thymus lymphoid cells and is one of the GM1b-derived gangliosides, GD1c, having two N-glycolylneuraminic acids. This is the first report on the occurrence of GD1c in normal animal cells.

A unique fucoganglioside with blood group B determinant in rat spleen.

A unique fucoganglioside was isolated from rat spleen and characterized by compositional analysis, methylation analysis, exoglycosidase treatment, negative ion fast atom bombardment (FAB) mass spectrometry, and proton NMR spectrometry. The ganglioside was identified as alpha Gal,Fuc-GM1(NeuGc), which has the blood group B determinant at the nonreducing termini, as shown below: (formula; see text) This is the first report describing the occurrence in nature of alpha Gal,Fuc-GM1 containing N-glycolylneuraminic acid.

Effect of a single oral dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin on immune function in male NC/Nga mice.

Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces immunosuppression in humans and animals. However, the effect of TCDD on Th2-type immune responses such as allergic reactions has been unclear. Using NC/Nga mice that developed atopic dermatitis-like skin lesions with marked elevation in plasma of total IgE when bred under conventional conditions, we investigated the effects of a single oral dose of TCDD on immune responses. NC/Nga mice received a single oral dose (0 or 20 microg/kg body weight) of TCDD. On day 7, treatment with TCDD alone decreased the cellularity of thymus. However, treatment with TCDD modified the cellularity of spleens and mesenteric lymph nodes (MLNs) but not of the thymus on day 28. When NC/Nga mice received ip immunization with OVA and alum on the same day as the TCDD treatment (0, 5, or 20 microg/kg body weight), TCDD markedly suppressed the concentrations of Th2-type cytokines (e.g., IL-4 and IL-5) in culture supernatants of spleen cells, whereas IFN-gamma production significantly increased. TCDD exposure reduced anti-OVA and total IgE antibody titers in plasma and did not induce the development of atopic dermatitis-like lesions in the pinnae or dorsal skin of NC/Nga mice. These results suggest that in NC/Nga mice, exposure to TCDD may impair the induction of Th2-type immune responses.

Alterations of thymocyte development, thymic emigrants and peripheral T cell population in rats exposed to 2,3,7, 8-tetrachlorodibenzo-p-dioxin.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exerts diverse biological effects by activating the cytosolic transcription factor, arylhydrocarbon receptor (AhR), which translocates to nuclei by TCDD binding and induces gene expressions. Among the well known-adverse effects of TCDD is thymus atrophy. In thymus atrophy, TCDD alters the proliferation as well as the differentiation of immature thymocytes. Previous studies on the effects of TCDD on thymocyte development were primarily carried out with high doses of TCDD. The present study investigates the effects of lower doses of TCDD (1 or 2 microg TCDD/kg by gavage) on thymocyte development, and furthermore, their sequential consequences on the peripheral T cell repertoire. Seven days after treatment with 1 or 2 microg TCDD/kg, the expression of CYP1A1 mRNA, one of the sensitive responses caused by the binding of TCDD to AhR, was detected in the thymus of rats. Thymus weights and thymus cell numbers decreased in TCDD-treated rats in a dose-dependent manner. The ratios of CD4 single-positive (SP) cells/CD8 SP cells were significantly reduced by TCDD exposure, indicating that the maturation of CD4(+)CD8(+) double-positive (DP) cells was skewed toward CD8 SP cells. These changes in the thymus were parallel to those previously observed with high doses of TCDD exposure. However, the specific reduction of DP cells reported in previous studies with high doses of TCDD was not detected in the present study. On the other hand, the skewing of mature CD4/CD8 T cell ratio in thymocytes by TCDD was not reflected in mesenteric lymph node (LN) lymphocytes, where the proportion of CD8 T cells was rather lowered by TCDD with a significant difference at 1 microg TCDD/kg. In LN lymphocytes, the percentage of recent thymic emigrants (RTEs), defined by the surface markers of Thy1(+)CD45RC(-), was shown to be significantly reduced by exposure to 1 and 2 microg TCDD/kg. T cell supply from the thymus has a crucial role in keeping the diversity of the T cell repertoire. The results of the present study indicated that lower doses of TCDD affect thymocyte development, especially differentiation, and reduce the proportion of RTE in LN, which may cause immunosuppression by reducing the variety of the T cell receptor repertoire.

The effects of perinatal exposure to low doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin on immune organs in rats.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is revealed to exert diverse biological effects including immunotoxicity, mainly by inadvertently activating the transcription factor arylhydrocarbon receptor (AhR). In the present study, the developmental effects of perinatal exposure to low doses of TCDD on the major immune organs of offspring, thymus and spleen, were investigated focusing on weaning time (postnatal day (PND) 21), puberty (PND 49) and adulthood (PND 120) in male rats. Concurrently, TCDD contents in those organs were measured with a high-resolution gas chromatography-mass spectrometry (GC/MS). In the thymus and spleen, CYP1A1 mRNA induction, the sensitive reaction caused by activation of AhR, was also measured in order to examine whether perinatally administered TCDD can elicit gene expressions in these organs. When pregnant dams were administered a single oral dose of 12.5-800 ng TCDD/kg body weight on gestation day (GD) 15, the weights of the thymus and spleen of the offspring did not differ from those of control animals throughout the experiments. The thymus and spleen maternally exposed to 800 ng TCDD/kg contained 102.0 and 62.7 pg TCDD/g tissue on PND 21, respectively, and the amounts decreased thereafter. In the thymus, dose-dependent CYP1A1 mRNA induction was clearly observed by maternal exposure to 50-800 ng TCDD/kg on PND 5. The induction was gradually decreased on PND 21 and 49. On the other hand, CYP1A1 mRNA induction in the spleen was very weak. In these thymi, no reproducible change was observed by TCDD exposure in cell number and cellular population defined by CD4 and CD8 molecules at any time. In contrast, splenocyte number was shown to decrease by maternal exposure to 12.5-800 ng TCDD/kg in a dose-dependent manner on PND 49. The alteration in spleen cellularity by TCDD was not detected on PND 21 or 120. These results clarified that perinatal exposure to low doses of TCDD affects the immune organs, which is apparent in spleen around puberty and likely to be hardly relevant to AhR-dependent gene expressions.

Effect of di-n-octyl phthalate on fatty acid composition of phosphatidylcholine in Tetrahymena.

We examined the effect of di-n-octyl phthalate (DOP) on fatty acid composition of phosphatidylcholine (PC) in Tetrahymena pyriformis NT-1. When Tetrahymena cells were grown in DOP-containing proteose peptone medium, the cell growth was repressed. This repression was attended by decreases in the PC content of the cells and decreases in oleic (18:1), linoleic (18:2) and linolenic (18:3) acids of PC and an increase in palmitoleic acid (16:1). The ratio of 18:1/stearic acid (18:0) of PC in cells grown in DOP-containing medium was lower than that of control cells, while the ratio of 16:1/palmitic acid (16:0) was higher than that of control. On the other hand, no changes in the ratios of 18:2/18:1 and 18:3/18:2 were observed. The activity of microsomal stearoyl-CoA desaturase from cells grown with DOP (0.63 mumol/ml medium) decreased to 27% of that from control cells, while the microsomal palmitoyl-CoA desaturase activity increased to 210% of the control value. By the addition of dioleoyl glyceride to the DOP-containing medium, the effects of DOP on Tetrahymena cells were completely blocked. These results suggest that the changes in fatty acid composition of PC may be due to the alteration of the substrate specificity of microsomal delta 9-desaturase, and the decrease in stearoyl-CoA desaturase activity may be a cause for the cell growth repression.

Induction of apoptosis in mouse thymocytes by cadmium.

In the thymus apoptosis is an important process in T cell maturation and differentiation. Cadmium (Cd) is an ubiquitous toxic metal that is capable of modulating immune responses. To investigate the induction of apoptosis and immunomodulation by environmental chemicals, we cultured mouse thymocytes with Cd and/or dexamethasone (DEX). DNA fragmentation was analyzed by gel electrophoresis, ELISA and flow cytometry. Treatment with either Cd or DEX induced DNA fragmentation in the thymocytes. Exposure to 10 microM Cd killed thymocytes by apoptosis rather than necrosis. However, no synergistic or additive effect was observed in the induction of apoptosis when DEX was added to the Cd. These results suggest that Cd may modulate the function of the thymus by the induction of apoptosis through mechanisms that differ from those used by DEX.

Effect of environmental pollutants on the production of pro-inflammatory cytokines by normal human dermal keratinocytes.

The effect of the environmental pollutants, diesel exhaust particles (DEP) and formaldehyde (FA), on the production of pro-inflammatory cytokines (interleukin (IL)-1alpha, IL-1beta, tumor necrosis factor (TNF)-alpha and IL-8) by normal human dermal keratinocytes (hKCs) was investigated. Normal hKCs were incubated with various concentrations of DEP (0.4, 0.8, 4, or 20 microg/ml) or FA (0.25, 0.5, 1, or 5 microg/ml), and cytokine production was then determined by enzyme-linked immunosorbent assay (ELISA). DEP (20 microg/ml) induced IL-1beta production without altering cell growth. The increased production of IL-1beta induced by this concentration of DEP was further enhanced by the presence of phorbol 12-myristate 13-acetate (PMA), although PMA alone did not affect the levels of IL-1beta. IL-8 production was also increased by DEP (0.4 and 0.8 microg/ml), which is consistent with the results that these concentrations of DEP increased the number of cells significantly after 72 h incubation. Although FA alone did not stimulate the production of IL-1beta or IL-8 by keratinocytes, FA (0.5 microg/ml and 5 microg/ml) significantly increased IL-8 and IL-1beta production, respectively, in cells stimulated with PMA. IL-1alpha production was not modulated by FA or DEP even in the presence of PMA. TNF-alpha was produced by unstimulated keratinocytes at barely detectable levels after 48 h incubation. Although basal levels of TNF-alpha in the culture supernatants were increased after stimulation with PMA, neither pollutant alone nor combination with PMA affected the levels of TNF-alpha. These in vitro findings suggest that environmental pollutants may act as modulating factors of cutaneous inflammation by affecting the ability of keratinocytes to release pro-inflammatory cytokines.