Do children from an inner city British school meet the recommended levels of physical activity? Results from a cross sectional survey using objective measurements of physical activity

Questionnaire surveys suggest physical activity levels in children are low, particularly among children from deprived areas. Using accelerometers, it was found that children from a deprived inner city school were active at recommended levels and had similar levels of activity to children in other studies from more affluent populations. However, this finding was dependent on the threshold used to define moderate activity.

CCR9-positive lymphocytes and thymus-expressed chemokine distinguish small bowel from colonic Crohn's disease

BACKGROUND & AIMS

Thymus-expressed chemokine (TECK) or CCL25) is selectively expressed in the small bowel (SB), where lamina propria lymphocytes (LPL) and intraepithelial leukocyte expressing the cognate chemokine receptor CCR9 predominate. We characterize the role of TECK and CCR9-expresing lymphocytes in small intestinal Crohn's disease.

METHODS

CCR9 expression on lymphocytes from lamina propria, mesenteric lymph node, and peripheral blood was analyzed by flow cytometry and by Northern blotting for LPL. TECK expression was analyzed in inflamed SB and colon by reverse-transcription polymerase chain reaction and immunohistochemistry.

RESULTS

The fraction of CCR9(+) T cells in inflamed SB was significantly lower than in uninvolved SB mucosa. In contrast, in peripheral blood lymphocytes, CCR9(+) lymphocytes were markedly elevated in patients with small bowel Crohn's or celiac disease, but not in patients with purely colonic Crohn's. Also, TECK expression is altered in inflamed small bowel, being intensely expressed in a patchy distribution in crypt epithelial cells in proximity to lymphocytic infiltrates. TECK is not expressed in either normal or inflamed colon.

CONCLUSIONS

In SB immune-mediated diseases, there is repartitioning of CCR9(+) lymphocytes between SB and blood and an altered pattern of TECK expression in SB Crohn's. The TECK/CCR9 ligand/receptor pair may play an important role in the pathogenesis of SB Crohn's disease.

Potent tumoricidal effects of a human cytotoxic T-cell line (TALL-104) against prostate cancer

The human TALL-104 cell line possesses major histocompatibility complex non-restricted cytotoxic activity against a large variety of tumor targets. Adequate therapies for prostate cancer that has spread outside its capsule are lacking. In order to identify effective therapies for this problem, we investigated the antiproliferative effects of TALL-104 cells against three prostate cancer cell lines (LNCaP, PC-3, DU-145). A Cr-51-release: cytotoxicity assay showed that TALL-104 cells were very cytotoxic against the prostate cancer cells. For example, at a 1:1 ratio of TALL-104 cells to prostate cancer cells, the percent release of Cr-51 at 18 h were 50, 40, and 45% for LNCaP, PC-3, and DU-145, respectively. Analysis by inhibition of clonogenic growth of prostate cancer cells also showed that TALL-104 cells were extremely effective. For instance, a short-term (4 h or 18 h) pre-incubation of TALL-104 cells with these tumor cells at the effector to target ratio of 10:1 prior to clonogenic assay resulted in a substantial reduction in clonogenic tumor growth (90%, 65%, and 50% clonal growth inhibition for LNCaP, PC-3, and DU-145, respectively). Further experiments using both Cr-51 release and clonogenic assays showed that irradiated TALL-104 cells were also effective in their anti-prostatic cancer activities. We also examined if TALL-104 cells plus a chemotherapeutic agent might complement each other in their cytotoxic effects. Preincubation of prostate cancer cell targets with etoposide (0.2-20 mu g/ml) for 18 h markedly increased their susceptibility to TALL-104 lysis. The anti-tumor efficacy of TALL-104 cells was also demonstrated in vivo utilizing the BNX murine model engrafted with subcutaneous PC-3 prostate cancer cells. A substantial reduction in PC-3 tumor cell progression was observed in mice injected with irradiated TALL-104 cells (1x10(7) cells intraperitoneally or intratumorally for 5 days beginning on days 24 and 45 after implantation) as compared to mice injected with tumors only. Taken together, these findings suggest that TALL-104 cells may be utilized as a potent anti-tumor agent, either alone or in combination with other agents (such as etoposide) in metastatic prostate cancer.

The expression of tumor necrosis factor in human adipose tissue. Regulation by obesity, weight loss, and relationship to lipoprotein lipase

A previous study reported the increased expression of the cytokine TNF in the adipose tissue of genetically obese rodents. To examine this paradigm in humans, we studied TNF expression in lean, obese, and reduced-obese human subjects. TNF mRNA was demonstrated in human adipocytes and adipose tissue by Northern blotting and PCR. TNF protein was quantitated by Western blotting and ELISA in both adipose tissue and the medium surrounding adipose tissue. Using quantitative reverse transcriptase PCR (RT-PCR), TNF mRNA levels were examined in the adipose tissue of 39 nondiabetic subjects, spanning a broad range of body mass index (BMI). There was a significant increase in adipose TNF mRNA levels with increasing adiposity. There was a significant correlation between TNF mRNA and percent body fat (r = 0.46, P < 0.05, n = 23). TNF mRNA tended to decrease in very obese subjects, but when subjects with a BMI > 45 kg/m2 were excluded, there was a significant correlation between TNF mRNA and BMI (r = 0.37, P < 0.05, n = 32). In addition, there was a significant decrease in adipose TNF with weight loss. In 11 obese subjects who lost between 14 and 66 kg (mean 34.7 kg, or 26.6% of initial weight), TNF mRNA levels decreased to 58% of initial levels after weight loss (P < 0.005), and TNF protein decreased to 46% of initial levels (P < 0.02). TNF is known to inhibit LPL activity. When fasting adipose LPL activity was measured in these subjects, there was a significant inverse relationship between TNF expression and LPL activity (r = -0.39, P < 0.02, n = 39). With weight loss, LPL activity increased to 411% of initial levels. However, the magnitude of the increase in LPL did not correlate with the decrease in TNF. Thus, TNF is expressed in human adipocytes. TNF is elevated in most obese subjects and is decreased by weight loss. In addition, there is an inverse relationship between TNF and LPL expression. These data suggest that endogenous TNF expression in adipose tissue may help limit obesity in some subjects, perhaps by increasing insulin resistance and decreasing LPL.

Measurement of tumor necrosis factor alpha mRNA in small numbers of cells by quantitative polymerase chain reaction

We have developed a method to quantitate TNF alpha-mRNA in small numbers of cells by reverse transcription followed by competitive polymerase chain reaction (RT-PCR). RT-PCR allowed the accurate quantitation of TNF alpha-mRNA over a 1000-fold range of concentration. The recovery of RNA isolated from 1000 to 10,000 cells was optimized by reducing sample volumes and by adding 1 microgram yeast RNA. Using these modifications we accurately measured TNF alpha-mRNA in as little as 10,000 U937 cells by RT-PCR. Then we measured TNF alpha-mRNA in lamina propria mononuclear cells isolated from uninflamed and inflamed colonic mucosa from patients with inflammatory bowel disease (IBD). A 9-fold increase (5.4 copies per cell) was found in mononuclear cells from the gut of the inflamed regions compared to those cells from the uninflamed regions (0.6 copies per cell). These findings demonstrated the utility of this method in measuring differences of expression of the TNF-alpha gene in small number of cells isolated from tissues.

Enhanced peripheral blood T-cell cytotoxicity in inflammatory bowel disease

Monoclonal antibodies to the CD3 component of the T-cell antigen receptor can trigger antigen-specific cytotoxic T cells to elicit nonantigen-specific cytotoxicity, possibly by mimicking or bypassing the requirement for antigen triggering. We have used this technique to investigate the possible presence of in vivo primed cytotoxic T cells, of unknown antigen specificity, in peripheral blood of patients with inflammatory bowel disease. Peripheral blood lymphocytes, which were depleted of background natural killer (NK) activity (CD16-), from patients with Crohn's disease exhibited significantly enhanced levels of anti-CD3-triggered T-cell cytotoxicity compared with lymphocytes from normal subjects. Enhanced lytic activity was also found in some patients with ulcerative colitis and in patients with ulcerative colitis postcolectomy. These results were not influenced by treatment or disease activity. There was no correlation between the anti-CD3-triggered T lytic activity and the NK activity in normal subjects or in patients with inflammatory bowel disease. The surface antigen phenotype of the anti-CD3-triggered T killer cell was CD3+, CD8+, CD16-, and Leu 7+. The results provide indirect evidence for increased activity of a subpopulation of cytotoxic T cells, of unknown antigen specificity, in inflammatory bowel disease. Increased activity in patients with ulcerative colitis postcolectomy suggests that this might reflect a fundamental immunological disturbance.

Human mucosal T-cell cytotoxicity

Non-major histocompatibility complex-restricted cytotoxicity triggered by antibodies to the CD3 component of the human T-cell receptor complex is thought to be an indirect measure of in vivo primed cytotoxic T-cell activity. We have used this technique to examine the lytic activity of freshly isolated T cells from noninflamed human colonic mucosa. Anti-CD3-triggered T-cell (anti-CD3-T) cytotoxicity was found in all mucosal specimens studied. The mucosal anti-CD3-T effectors do not have Fc receptors for immunoglobulin G, and are therefore distinct from T gamma cells, which mediate antibody-dependent cellular cytotoxicity. The surface antigen phenotype of mucosal anti-CD3-Ts is CD2+, CD3+, CD8+, CD4-, CD16-, and Leu7-. In contrast, peripheral blood anti-CD3-T effectors are Leu7+. Although non-major histocompatibility complex-restricted, mucosal anti-CD3-T cytotoxicity has considerable target specificity, which differs from that of natural killer and lymphokine-activated killer cells. The profile of target cell susceptibility and the inhibitory effects of anti-CD45 antibody suggest that the CD45 molecule on the effector cell may be an important determinant of anti-CD3-T sensitivity. As anti-CD3-triggered lysis may be a marker of in vivo primed mucosal T cells of undetermined antigen specificity, this technique might have important implications in inflammatory bowel disease, where the antigen(s) inciting the mucosal immune reactivity is not certain.

Purification and properties of a unique superoxide dismutase from Nocardia asteroides

A unique form of superoxide dismutase was isolated and characterized from Nocardia asteroides GUH-2. This enzyme contains 1 to 2 g atoms each of Fe, Mn, and Zn per mol and exhibits spectral properties suggestive of Fe- or Mn-containing superoxide dismutases. Its Mr = 100,000, and it is composed of four subunits of equal size which are not covalently joined. The amino acid composition of the enzyme was more closely related to the Mn- or Fe-containing enzymes of Mycobacterium species and was least related to the Cu-Zn enzyme of eukaryotes. Azide at 1 and 20 mM inhibits the activity 10 and 41%, respectively, and 5 mM H2O2 inhibits 40%, but 1 or 5 mM cyanide caused trivial effect. The immunofluorescent staining, which was specific for superoxide dismutase of N. asteroides, indicated the association of this enzyme to the outer cell wall of the organism. Further, the enzyme was shown to be selectively secreted into the medium.

Response of CBA/N x DBA2/F1 mice to Nocardia asteroides

Immunized and nonimmunized B-lymphocyte-deficient CBD2/F1 (CBA/N x DBA/2) mice were infected with Nocardia asteroides GUH-2 by different routes of inoculation. The 50% lethal dose, organ clearance, footpad response, and antibody titers were measured. It was observed that B-cell-deficient male mice were not significantly more susceptible to infection than normal female controls even though the female CBD2/F1 mice produced antinocardial antibodies while the deficient male animals did not. Preimmunized male and female mice were identical in their ability to clear N. asteroides from the adrenals, brain, kidneys, liver, lungs, and spleen. Both DBA/2 and CBD2/F1 female mice were more susceptible than their male littermates to intravenous challenge with N. asteroides GUH-2. This enhanced susceptibility of the female mice as compared to the male littermates appeared to be due to a decreased resistance to nocardial infections in the brains of the female animals. These data indicate that antibody and certain B-lymphocyte subpopulations are not essential components in host resistance to N. asteroides GUH-2 in these mice.