Mast cells are upregulated in hidradenitis suppurativa tissue, associated with epithelialized tunnels and normalized by spleen tyrosine kinase antagonism

Mast cells have traditionally been associated with allergic inflammatory responses; however, they play important roles in cutaneous innate immunity and wound healing. The Hidradenitis Suppurativa tissue transcriptome is associated with alterations in innate immunity and wound healing-associated pathways; however, the role of mast cells in the disease is unexplored. We demonstrate that mast cell-associated gene expression (using whole tissue RNAseq) is upregulated, and in-silico cellular deconvolution identifies activated mast cells upregulated and resting mast cells downregulated in lesional tissue. Tryptase/Chymase positive mast cells (identified using IHC) localize adjacent to epithelialized tunnels, fibrotic regions of the dermis and at perivascular sites associated with Neutrophil Extracellular Trap formation and TNF-alpha production. Treatment with Spleen Tyrosine Kinase antagonist (Fostamatinib) reduces the expression of mast cell-associated gene transcripts, associated biochemical pathways and the number of tryptase/chymase positive mast cells in lesional hidradenitis suppurativa tissue. This data indicates that although mast cells are not the most abundant cell type in Hidradenitis Suppurativa tissue, the dysregulation of mast cells is paralleled with B cell/plasma cell inflammation, inflammatory epithelialized tunnels and epithelial budding. This provides an explanation as to the mixed inflammatory activation signature seen in HS, the correlation with dysregulated wound healing and potential pathways involved in the development of epithelialized tunnels.

Exercise training-induced modification of the gut microbiota persists after microbiota colonization and attenuates the response to chemically-induced colitis in gnotobiotic mice

Exercise reduces the risk of inflammatory disease by modulating a variety of tissue and cell types, including those within the gastrointestinal tract. Recent data indicates that exercise can also alter the gut microbiota, but little is known as to whether these changes affect host function. Here, we use a germ-free (GF) animal model to test whether exercise-induced modifications in the gut microbiota can directly affect host responses to microbiota colonization and chemically-induced colitis. Donor mice (n = 19) received access to a running wheel (n = 10) or remained without access (n = 9) for a period of six weeks. After euthanasia, cecal contents were pooled by activity treatment and transplanted into two separate cohorts of GF mice. Two experiments were then conducted. First, mice were euthanized five weeks after the microbiota transplant and tissues were collected for analysis. A second cohort of GF mice were colonized by donor microbiotas for four weeks before dextran-sodium-sulfate was administered to induce acute colitis, after which mice were euthanized for tissue analysis. We observed that microbial transplants from donor (exercised or control) mice led to differences in microbiota β-diversity, metabolite profiles, colon inflammation, and body mass in recipient mice five weeks after colonization. We also demonstrate that colonization of mice with a gut microbiota from exercise-trained mice led to an attenuated response to chemical colitis, evidenced by reduced colon shortening, attenuated mucus depletion and augmented expression of cytokines involved in tissue regeneration. Exercise-induced modifications in the gut microbiota can mediate host-microbial interactions with potentially beneficial outcomes for the host.

The phototoxicity of vemurafenib: An investigation of clinical monochromator phototesting and in vitro phototoxicity testing

BACKGROUND

Vemurafenib is a targeted therapy approved for the treatment of patients with metastatic melanoma harbouring the BRAF V600E mutation. Photosensitivity has been reported in over 50% of patients and has been demonstrated to involve at least the broadband UVA spectrum in most patients. Erythrocyte protoporphyrin levels have also been reported as elevated in some patients.

OBJECTIVES

We report the results of monochromator phototesting in one patient recorded before and while taking vemurafenib. Analysis of porphyrin levels was also conducted.

RESULTS

After one month of vemurafenib therapy the patient demonstrated markedly increased light sensitivity in the UVA spectrum between 335 ± 27 nm, 365 ± 27 nm and 400 ± 27 nm. However responses in the UVB (305 ± 5 nm) and blue light (430 ± 27 nm) regions were normal. There was no abnormal immediate erythemal response. Pre-vemurafenib baseline phototesting was normal, as was repeat testing two months later when the patient was taking high doses of systemic steroid. No abnormal porphyrins were detected and the antinuclear antibody test was normal. In parallel studies, HaCaT keratinocytes incubated with vemurafenib were killed by UVA but not by visible (blue) light and did not show evidence of detectable intracellular porphyrin in the presence of the drug.

CONCLUSION

These data confirm vemurafenib induced UVA photosensitivity with a probable phototoxic mechanism not mediated via enhanced porphyrin.

Photodynamic therapy in dermatology: Dundee clinical and research experience

Topical photodynamic therapy (PDT) is increasingly accepted and used as a highly effective treatment for superficial non-melanoma skin cancer and dysplasia. We describe the developments in topical PDT for the treatment of skin diseases in our own PDT Centre in Dundee, both clinically and from a research base. Improvements in PDT could be achieved by optimisation of photosensitiser and light delivery, and these goals underpin the aims of our centre. We hope to facilitate the dissemination of use of PDT in dermatology throughout Scotland and outline some of the progress in these areas.

Effect of sex on wasted left ventricular effort following maximal exercise

Wasted left ventricular effort (∆Ew) refers to work required of the left ventricle to eject blood that does not result in increased stroke volume and is related to left ventricular hypertrophy. Literature shows that men and women have differing ventricular and vascular responses to and following exercise. Our purpose was to determine how ∆Ew changes post-exercise in men and women and examine potential mechanisms. We hypothesized a reduction in ∆Ew that would be greater in men and that central pulse wave velocity and wave intensity (WIA) would be related to ∆Ew. Blood pressures, central pulse wave velocity (cPWV), and WIA were obtained at rest, 15 and 30 min after maximal exercise. Both sexes reduced ∆Ew post-maximal exercise (p>0.05 for interaction), but women had higher ∆Ew at each time point (p<0.05). The first peak of WIA increased 15 min post-exercise only in women (p<0.05). cPWV was attenuated (p<0.05) in women at 15 min and men at 30 min (p<0.05) post-exercise with a significant time by sex interaction (p<0.05). WIA (1st peak) was correlated (p<0.05) to ∆Ew in both sexes before and 15 min post-exercise, but cPWV was only associated with ∆Ew in men at 30 min post-exercise. We conclude that both sexes decrease ∆Ew after maximal exercise, but vascular and ventricular changes associated with the attenuation of ∆Ew are not uniform between sexes.

Cyclobutane pyrimidine dimers are photosensitised by carprofen plus UVA in human HaCaT cells

Every year in the UK about 75,000 cases of non-melanoma skin cancer (NMSC) are registered, and about 9500 people are diagnosed with cutaneous melanoma (CM). The main risk factor for these cancers is exposure to sunlight. The effects of light on skin are wavelength dependent, with wavelengths in the UVB waveband (280-315 nm) being the most carcinogenic. UVB is directly absorbed by DNA, producing dimeric pyrimidine photoproducts including cyclobutane pyrimidine dimers (CPD) and pyrimidine (6-4) pyrimodone photoproducts (6-4PP). However UVA (315-400 nm) can also produce CPD, induce skin tumours in mice, and has been shown to be mutagenic in cell culture. Although the precise role of UVA in human skin cancer remains to be elucidated, it comprises the major portion of solar UV radiation, transmits through window glass and can be delivered in high doses from tanning lamps. Non-steroidal anti-inflammatory drugs (NSAIDs), in particular the 2-aryl propionic acid derivatives, are a well-documented group of photosensitising chemicals producing clinical phototoxic and photoallergic reactions. We have used carprofen, a model compound from this group to see if it could amplify the effects of UVA and contribute to the formation of CPD by UVA. Preliminary work has shown that carprofen combined with low doses of UVA (lambda(max): 365 nm; 5 J/cm(2)) can produce both strand breaks (SB) and CPD in human skin or blood cells. CPD were detected indirectly by both an immunofluorescence method and as T4 endonuclease V sensitive sites in the comet assay. These findings show that compounds other than fluoroquinolones and psoralen derivatives may contribute to CPD formation in skin cells in combination with UVA.

Reduction in trunk fat predicts cardiovascular exercise training-related reductions in C-reactive protein

C-reactive protein (CRP) is an independent risk factor for cardiovascular disease. We sought to determine (1) if 10 months of cardiovascular exercise training (Cardio) reduces CRP in a group of older adults, (2) if such a reduction is related to improvements in trunk fat, fitness, and/or psychosocial variables, and (3) if the effect of Cardio on CRP differs between men and women. Community-dwelling residents (n=127; 60-83 yrs) were randomized to a Flex group (n=61) where they participated in 2-75 min supervised sessions per wk during which they performed non-cardiovascular flexibility and balance exercises or a Cardio group (n=66) where they participated in three supervised sessions per wk during which they performed cardiovascular exercises for approximately 45-60 min at 60-70% maximal oxygen uptake. The main outcome measures were serum CRP, cardiovascular fitness, total and central adiposity, and self-reported psychosocial function. Cardio experienced a reduction in CRP (-0.5mg/L), as well as improvements in fitness (+7%) and total (-1.5%) and central (i.e., trunk) (-2.5%) adiposity. These relationships were not modified by sex. Regression analyses indicated that only the reduction in trunk fat was significantly related to the reduction in CRP. Ten months of cardiovascular exercise training reduced CRP in previously sedentary older adults and this effect was partially mediated by a reduction in trunk fat.

Cardiovascular exercise intervention improves the primary antibody response to keyhole limpet hemocyanin (KLH) in previously sedentary older adults

Based upon a prior cross-sectional study, we hypothesized that an aerobic exercise intervention in sedentary older adults would improve a primary T cell-dependent immune response. Participants were a subset of older subjects from a large, ongoing exercise intervention study who were randomly assigned to either an aerobic exercise (Cardio, n=30, 68.9+0.8 years) or flexibility/balance (Flex, n=20, 69.9+1.2 years) intervention. The intervention consisted of either three aerobic sessions for 30-60 min at 55-70% VO(2 max) or two 60 min flexibility/balance sessions weekly for 10 months. Eight months into the intervention, samples were collected before intramuscular administration of KLH (125 microg), followed by sampling at 2, 3, and 6 weeks post-KLH. Serum anti-KLH IgM, IgG1, and IgG2 was measured by ELISA. Physiological and psychosocial measures were also assessed pre- and post-intervention. While there was no difference in the anti-KLH IgG2 response between groups, Cardio displayed significantly (p<0.05) higher anti-KLH IgG1 (at weeks 2, 3, and 6 post) and IgM responses when compared to Flex. Despite cardiovascular intervention-induced improvement in physical fitness (approximately 11% vs. 1% change in VO(2 peak) in Cardio vs. Flex, respectively), we found no relationship between improved fitness and enhanced anti-KLH antibody responses. Optimism, perceived stress, and affect were all associated with enhanced immune response. We have shown for the first time that cardiovascular training in previously sedentary elderly results in significantly higher primary IgG1 and IgM antibody responses, while having no effect on IgG2 production.

Can St John's wort (hypericin) ingestion enhance the erythemal response during high-dose ultraviolet A1 therapy?

BACKGROUND

St John's wort (SJW) is widely used as a treatment for depression. A phototoxic reaction, due to its content of hypericin, can occur in animals and in cell culture, and has been reported in humans. Hypericin displays absorption within the ultraviolet (UV) A1 spectrum and there may therefore be a potential for phototoxicity if taken during high-dose UVA1 therapy.

OBJECTIVES

To assess the phototoxicity risk of SJW ingestion.

METHODS

Eleven adult volunteers of skin types I and II were exposed to a geometric dose series of UVA1 irradiation from a high-output source (Dermalight Ultra 1; Dr Hönle, Martinsreid, Germany; irradiance 70-77 mW cm(-2)) on the photoprotected lower back skin at eight 1.5-cm(2) test areas. Irradiation was carried out at baseline and after 10 days of SJW extract 1020 mg (equivalent to 3000 microg of hypericin) daily. Four, 8, 24 and 48 h after each exposure, the minimal erythema dose (MED) and the presence or absence of pigmentation were recorded visually and erythema was assessed objectively with an erythema meter.

RESULTS

The median MED and D(0.025), an objective measure of MED, were lower at all time-points after SJW ingestion. The visual erythemal peak (lowest median MED), which was seen at 8 h postirradiation, was lower after SJW (median 14 J cm(-2), range 10-56) than at baseline (median 20 J cm(-2), range 14-56) (P = 0.047). Similarly, the median D(0.025) at 8 h postirradiation was lower after SJW (median 22.0 J cm(-2), range 15.2-53.9) than at baseline (median 33.7 J cm(-2), range 22.9-136.0) (P = 0.014). The MED and D(0.025) were also significantly different at the 48-h and 4-h time-points, respectively. Significance was not reached at the 24-h time-point. Median intensity of postirradiation erythema increased at all time-points after ingestion of SJW. Despite these differences, the maximum slope of the dose-response curve was not increased after SJW ingestion.

CONCLUSIONS

These data suggest that SJW extract has the potential to lower the erythemal threshold to UVA1 irradiation in a significant proportion of individuals and highlight the importance of ascertaining a full drug history, including herbal remedies, before initiating UVA1 phototherapy.

Photogenotoxicity of hypericin in HaCaT keratinocytes: Implications for St. John's Wort supplements and high dose UVA-1 therapy

Extract of St. John's Wort (Hypericum perforatum) is commonly used as natural remedy for treatment of mild to moderate depression. However, it contains a powerful photoactive component, hypericin, which can cause a severe photodermatitis when eaten by grazing animals (hypericism). In humans, there is evidence that supplementation with St. John's Wort can reduce the minimal erythemal dose (MED) in patients undergoing high dose UVA-1 phototherapy. This is a recent development in phototherapy where the most erythemogenic parts of the UVA spectrum are filtered out, allowing delivery of higher doses of the longer wavelengths of UVA. Although current published evidence suggests that the plasma levels of hypericin are unlikely to cause clinical phototoxicity, it has been established that photoactive compounds can cause DNA damage at sub-toxic and sub-erythemal doses, the effects of which might not be apparent for many years after the event. The present study used HaCaT keratinocytes to investigate the photoclastogenic ability of hypericin on irradiation with UVA. The results show that although the combination of hypericin and UVA light increased the genotoxic burden, when all factors are taken into account, the risk of significant photogenotoxic damage incurred by the combination of Hypericum extracts and UVA phototherapy may be low in the majority of individuals.

Selected hormonal and immunological responses to strenuous live-fire firefighting drills

This study investigated the effects of strenuous live-fire firefighting drills and a 90 min recovery period on selected hormonal, immunological and psychological variables. Apparently healthy, male, professional firefighters (n = 11) performed three trials of standardized firefighting tasks in a live-fire training structure. There was significant leukocytosis immediately post firefighting activity that persisted following recovery, although there was a variable response among the leukocyte subsets. Most notable was the decrease in number and percentage of lymphocytes following 90 min of recovery. Plasma levels of ACTH and cortisol were significantly elevated post firefighting activity and cortisol remained elevated following 90 min of recovery. Elevated cortisol immediately following activity was related to reduced feelings of energy. These data demonstrate the magnitude of the physiological and psychological disruption following strenuous firefighting activity and suggest that immune function may be altered following such activity. This is a finding that may have practical consequences for this group of first responders.

Can a positive photopatch test be elicited by subclinical irritancy or allergy plus suberythemal UV exposure?

Photopatch test (PhPT) interpretation is difficult and clinical relevance is not always apparent. A positive PhPT may reflect photocontact allergy or phototoxicity. We hypothesized that it may also reflect the additive or synergistic effects of a suberythemal reaction to a contact irritant [e.g. sodium lauryl sulfate (SLS)] or allergen (e.g. nickel) and suberythemal UV exposure. 10 nickel allergic volunteers had duplicate SLS and nickel series applied on either side of the back for 24 h and 48 h, respectively. After removal, one side was irradiated with 5 J/cm(2) UVA or the dose below the minimal erythema dose for solar-simulated radiation (SSR). The minimal irritancy dose (MID) for SLS and the minimal allergenic dose (MAD) for nickel were determined visually and objectively by erythema meter. While photoaugmentation of subclinical contact allergy or irritancy occurred in some subjects, photosuppression occurred in roughly an equal number. UVA changed the nickel MAD at 48 h in 2 of 5 volunteers but not the SLS MID. SSR changed the nickel MAD in 4 of 5 and the SLS MID in 3 of 5. 2 subjects (none after UVA) showed erythema only in the irradiated set of patches, which could have been interpreted as a positive PhPT. We have demonstrated photoaugmentation and photosuppression of contact allergy and irritancy, which could result in false-positive or false-negative interpretation of PhPTs.

Macrophage hypo-responsiveness to interferon-gamma in aged mice is associated with impaired signaling through Jak-STAT

Since macrophages (Mphis) are a first line of defense against pathogens, and are involved in both innate and adaptive immunity, understanding the impact of aging on Mphi function is important. In the past studies, we and others have shown that aging decreases Mphi responsiveness to classical activating signals (e.g. IFN-gamma and lipopolysaccharide, LPS). In this study, we examined the impact of aging on Mphi signaling through the IFN-gamma receptor pathway. Mphis from male Balb/c mice aged 2 (young) and 18-24 (old) months were purified and then stimulated with IFN-gamma. Western blotting revealed a significant reduction ( approximately 50%) in IFN-gamma-stimulated tyrosine phosphorylation of signal transducer and activator of transcription-1 (STAT-1) alpha and beta in Mphis from aged, when compared with young mice. This reduction in phospho-STAT-1 was associated with a significant constitutive reduction ( approximately 80%) in total STAT-1alpha protein and a complete inhibition of STAT-1 gene expression in response to IFN-gamma in old compared to young mice. These data may, in part, explain why classical Mphi responses like reactive nitrogen and oxygen species generation, tumor killing and microbicidal activity are lower in Mphis from aged subjects. We conclude that peritoneal Mphis from aged mice have an intrinsic defect in Jak-STAT signaling which prevents them from fully responding to IFN-gamma.

The effect of photofrin on DNA strand breaks and base oxidation in HaCaT keratinocytes: a comet assay study

Photodynamic therapy (PDT) kills cells via the production of singlet oxygen and other reactive oxygen species. PDT causes chromosomal damage and mutation to cultured cells. However, DNA damage does not contribute to the phototoxic effect. To study the effect of Photofrin-PDT-induced DNA damage, we used the comet assay in combination with endonuclease III and formamidopyrimidine DNA glycosylase and a human keratinocyte cell line to investigate photogenotoxicity and its prevention by tocopherol (TOC). This study shows that PDT induced DNA damage in HaCaT cells at doses allowing cells to survive 7 days after irradiation. alpha-TOC did not prevent the acute cell lysis caused by Photofrin-PDT but did prevent Photofrin-PDT-induced DNA damage. However, the concentration of TOC that conferred protection (100 microM) was higher than is detected in human serum. Base oxidation was also measured using the comet assay. Although TOC could prevent frank DNA strand breaks caused by PDT, it was unable to decrease the level of base oxidation as revealed by enzyme-sensitive sites. It is suggested that the potential genotoxic risk from laser-PDT could be low, and that topical micro-TOC at a high concentration may be useful in preventing some types of DNA damage without preventing acute photolysis after Photofrin-PDT.

Exercise training increases the näive to memory T cell ratio in old mice

Aging is associated with changes in T cells including involution of the thymus gland and an imbalance in the proportion of näive (CD44lo) and memory (CD44hi) T cells in the periphery. Reversal of these changes may improve immunity in the aged. We sought to determine whether 4 months of moderately intense treadmill running (EXC; 5 days/week, 45 min/day, 13-22 m/min) in 2 month (Y) and 18 month (O) old male Balb/c mice would alter T lymphocyte profiles in the thymus and spleen when compared to sedentary controls (CON). Splenocytes and thymocytes were harvested 24-48 h after the last exercise session and analyzed using immunofluorescence and flow cytometry. While there were significant age-related changes (lower cell number, altered subsets) in the thymuses of O when compared to Y mice, exercise training failed to affect any of these measures in mice of either age. Aged mice exhibited a significantly (p < .05) higher percentage of splenic memory cells and a lower percentage of näive cells in both the CD4 and CD8 T cell subsets. Interestingly, exercise training significantly (p < .05) increased the percentage of näive and decreased the percentage of memory cells in both the CD4+ (69.6+/-1.7% näive and 30.4+/-1.7% memory for OCON vs. 75.0+/-1.5% näive and 25.0+/-1.5% memory in OEXC) and CD8+ (60.0+/-2.6% näive and 40.0+/-2.6% memory in OCON vs. 76.7+/-2.7% näive and 23.3+/-2.7% memory in OEXC) T cells subsets in O, but not Y, mice. This effect was due to a decrease in the absolute number of memory cells and not an increase in the absolute number of näive cells. We conclude that 4 months of EXC has little restorative effect on the thymus in aged mice, but can restore the percentages of näive and memory cells in the spleen towards that of young mice, perhaps due to removal of memory cells.

Toxicity of cholesterol oxidation products to Caco-2 and HepG2 cells: modulatory effects of alpha- and gamma-tocopherol

Cholesterol can be oxidized to form a variety of cholesterol oxidation products also known as oxysterols. The aims of the present study were to compare the cytotoxic effects of four oxysterols, namely 25-hydroxycholesterol (25-OHC), 7beta-hydroxycholesterol (7beta-OHC), cholesterol-5beta,6beta-epoxide (beta-epox) and cholesterol-5alpha,6alpha-epoxide (alpha-epox), in two human cell culture models. Further, the ability of 10 and 100 micro m alpha- and gamma-tocopherol (alpha-TOC and gamma-TOC, respectively) to protect against oxysterol-induced cytotoxicity was also assessed. Human colonic adenocarcinoma Caco-2 and human hepatoma HepG2 cells were supplemented with increasing concentrations of 25-OHC, 7beta-OHC, beta-epox and alpha-epox (0-25 micro g ml(-1)) for 24, 48 or 96 h. Following 24-h and 48-h exposure, test media were replaced with normal growth media and the cells were maintained for 72 and 48 h, respectively. The 96-h exposure represented a constant challenge to the cells. Cytotoxicity was assessed using the neutral red uptake assay. The concentration of compound that inhibited cell viability by 50% (ic(50) value) was calculated. All four oxysterols investigated induced the greatest cytotoxic effects following 96 h of exposure. 25-Hydroxycholesterol exhibited the greatest cytotoxicity in both cell lines. Both beta-epox and alpha-epox were more toxic to HepG2 cells than to Caco-2 cells after the 48-h exposure. Pretreatment of cells with either alpha- or gamma-TOC did not protect against oxysterol-induced cytotoxicity. The caco-2 cells treated with the high concentration (100 micro m) of gamma-TOC were found to be more susceptible to oxysterol-induced toxicity under the conditions employed in this study.

Characteristics of 7 beta-hydroxycholesterol-induced cell death in a human monocytic blood cell line, U937, and a human hepatoma cell line, HepG2

Oxysterols have been shown in a number of cell lines to induce apoptosis by a mechanism as yet unclear. The induction of apoptosis by certain agents has been associated with the generation of oxidative stress and the depletion of the endogenous antioxidant, glutathione, which may result in cytochrome c release and caspase activation. The aim of the present study was to determine whether 7 beta-hydroxycholesterol (7 beta-OH) alters glutathione levels or the activities of catalase, superoxide dismutase (SOD) or caspase-3 in association with cell death in either the U937 or the HepG2 cell lines. 7 beta-OH, which induced significant apoptosis at 12 h in the U937 cell line, was shown to cause a significant decrease in glutathione levels and an increase in the activity of SOD at this time point. An increase in caspase-3 activity was also observed in the U937 cell line following a 24-h incubation with 7 beta-OH. Glutathione concentration, SOD activity and caspase-3 activity were unchanged in the HepG2 cell line, which underwent necrosis following incubation with 7 beta-OH. The activity of the enzyme catalase remained unchanged in both cell lines. These results provide evidence that the generation of an oxidative stress may be a significant event occurring during 7 beta-OH-induced apoptosis.

Sedanolide, a natural phthalide from celery seed oil: effect on hydrogen peroxide and tert-butyl hydroperoxide-induced toxicity in HepG2 and CaCo-2 human cell lines

Sedanolide is a natural compound occurring in edible umbelliferous plants. Celery seed oil, a significant source of sedanolide, is used as an herbal remedy to treat inflammatory-associated conditions such as gout and rheumatism. The objective of this study was to assess the potential protective properties of sedanolide against hydrogen peroxide (H(2)O(2))- and tert-butyl hydroperoxide (tBOOH)-induced toxicity in HepG2 and CaCo-2 cells. Viability of HepG2 and CaCo-2 cells was unaffected by a 24-h exposure to sedanolide (7-500 microM), however, when the cells were cultured in sedanolide-free medium for a further two cell cycles (72 h), a decrease in cell viability was observed for HepG2 cells previously exposed to 500 microM of the compound. Cells pretreated with sedanolide (100 microM for 24 h) and exposed to either H(2)O(2) or tBOOH did not exhibit statistically significant difference in viability from controls. A significant increase (p < 0.05) in DNA strand breaks, as measured by the comet assay, was observed in HepG2 but not CaCo-2 cells following a 24-h incubation with 500 microM sedanolide. Sedanolide did not modulate H(2)O(2)- and tBOOH-induced DNA damage. Sedanolide is relatively nontoxic to cells in culture, however, the protection it afforded against H(2)O(2)- and tBOOH-induced toxicity was not statistically significant.

Comparative study of the cytotoxicity and apoptosis-inducing potential of commonly occurring oxysterols

The cytotoxicity of the oxysterols 25-hydroxycholesterol, 7beta-hydroxycholesterol, cholesterol-5alpha,6alphaepoxide, cholesterol-5beta,6beta-epoxide, 19-hydroxycholesterol and 7-ketocholesterol was examined in U937 cells, a human monocytic blood cell line. 7beta-Hydroxycholesterol, cholesterol-5beta,6beta-epoxide, and 7-ketocholesterol, at 30 micromol/L concentration, were found to be cytotoxic to this cell line and the mode of cell death was by apoptosis. 25-Hydroxycholesterol, cholesterol-5alpha,6beta-epoxide and 19-hydroxycholesterol (30 micromol/L) did not induce apoptosis in this cell line. Since it has been suggested that the generation of an oxidative stress may occur in the early stages of the apoptotic process, the glutathione concentration and the activity of superoxide dismutase were also measured in the oxysterol-treated cells. 7beta-Hydroxycholesterol was shown to increase the superoxide dismutase activity and decrease the glutathione concentration. However, cholesterol-5beta,6beta-epoxide and 7-ketocholesterol, which were also shown to induce apoptosis, did not affect the glutathione concentration or the superoxide dismutase activity in the U937 cells. Therefore, oxysterol-induced apoptosis may not be dependent on the generation of an oxidative stress.

Gamma-tocopherol is less effective than alpha-tocopherol in preventing oxidant-induced sister chromatid exchanges in Chinese hamster V79 cells

Although alpha-tocopherol (alpha-TOC) is the most biologically active form of vitamin E and is found at high levels in plasma, gamma-tocopherol (gamma-TOC) has also been found to be a powerful antioxidant in vitro and constitutes up to 70% of the dietary intake of TOC. Low plasma levels of gamma-TOC and a high alpha-TOC:gamma-TOC ratio may be associated with coronary heart disease, suggesting that there may be a positive protective role for the gamma-form of TOC. In this study the ability of different forms of vitamin E to protect against sister chromatid exchanges (SCE) induced by either hydrogen peroxide or menadione was investigated. Chinese hamster V79 cells were pre-treated with 10 microM TOC for 24 h, and then challenged with a genotoxin. After a 24 h pre-treatment, there was a greater incorporation of gamma-TOC (319.8 +/- 66.2 ng/10(6) cells) into V79 cells compared to alpha-TOC (66.9 +/- 6.4 ng/10(6) cells). Gamma-TOC did not protect the cells against SCE induced by either hydrogen peroxide or menadione, alpha-TOC acetate was partially protective against both genotoxins, whereas alpha-TOC completely abolished the oxidant induced SCE. These results demonstrate that, despite a greater incorporation of gamma-TOC into V79 cells, alpha-TOC but not gamma-TOC was more effective at inhibiting oxidatively-induced SCE in V79 cells.

Cell-type specific effects of endocytosis inhibitors on 5-hydroxytryptamine(2A) receptor desensitization and resensitization reveal an arrestin-, GRK2-, and GRK5-independent mode of regulation in human embryonic kidney 293 cells

The effect of endocytosis inhibitors on 5-hydroxytryptamine(2A) (5-HT(2A)) receptor desensitization and resensitization was examined in transiently transfected human embryonic kidney (HEK) 293 cells and in C6 glioma cells that endogenously express 5-HT(2A) receptors. In HEK-293 cells, 5-HT(2A) receptor desensitization was unaffected by cotransfection with a dominant-negative mutant of dynamin (DynK44A), a truncation mutant of arrestin-2 [Arr2(319-418)], or by two well-characterized chemical inhibitors of endocytosis: concanavalin A (conA) and phenylarsine oxide (PAO). In contrast, beta 2-adrenergic receptor desensitization was significantly potentiated by each of these treatments in HEK-293 cells. In C6 glioma cells, however, DynK44A, Arr2(319-418), conA, and PAO each resulted in the potentiation of 5-HT(2A) and beta-adrenergic receptor desensitization. The cell-type-specific effect of Arr2(319-418) on 5-HT(2A) receptor desensitization was not related to the level of GRK2 or GRK5 expression. Interestingly, although beta 2-adrenergic receptor resensitization was potently blocked by cotransfection with DynK44A, 5-HT(2A) receptor resensitization was enhanced, suggesting the existence of a novel cell-surface mechanism for 5-HT(2A) receptor resensitization in HEK-293 cells. In addition, Arr2(319-418) had no effect on 5-HT(2A) receptor resensitization in HEK-293 cells, although it attenuated the resensitization of the beta 2-adrenergic receptor. However, in C6 glioma cells, both DynK44A and Arr2(319-418) significantly reduced 5-HT(2A) receptor resensitization. Taken together, these results provide the first convincing evidence of cell-type-specific roles for endocytosis inhibitors in regulating GPCR activity. Additionally, these results imply that novel GRK and arrestin-independent mechanisms of 5-HT(2A) receptor desensitization and resensitization exist in HEK-293 cells.

alpha-Tocopherol, but not gamma-tocopherol inhibits 7 beta-hydroxycholesterol-induced apoptosis in human U937 cells

Oxysterols, particularly those oxidised at position 7, are toxic to cells in culture and have been shown to induce apoptosis in cell types such as vascular endothelial cells, smooth muscle cells and monocytes. The precise mechanism by which oxysterols induce apoptosis is unknown but may involve the generation of oxidative stress. In the present study we examined the ability of alpha-TOC, alpha-TOC acetate (alpha-TOCA) and gamma-TOC to protect against 7 beta-hydroxycholesterol (7 beta-OHC)-induced apoptosis of human monocytic U937 cells. 7 beta-OHC is one of the most commonly detected oxysterols in foods and its level in plasma has been positively associated with an increased risk of atherosclerosis. The present study demonstrates a significant decrease in cell membrane integrity and cellular glutathione levels when U937 cells were treated with 30 microM 7 beta-OHC. DNA fragmentation also occurred, as measured by agarose gel electrophoresis, and the number of apoptotic cells increased as assessed by nuclear morphology. Analysis by HPLC showed that there was a greater incorporation of gamma-TOC into U937 cells after a 48 h incubation, than either alpha-TOC or alpha-TOCA. However, despite the increased uptake of gamma-TOC, only alpha-TOC, and not gamma-TOC or alpha-TOCA was effective at inhibiting 7 beta-OHC-induced apoptosis in U937 cells.

A critical evaluation of the application of biomarkers in epidemiological studies on diet and health

One of the problems which may beset epidemiological studies is the difficulty of accurately measuring the dietary intakes of participants. Biomarkers of diet promise to provide a more accurate measure of dietary intake and a more objective one in that they are not reliant on the subject's memory. This review considers some issues of importance in epidemiology when information is obtained from biomarkers. The approach taken is to use examples both of normal dietary constituents and of contaminants in relation to a range of diet and health questions to illustrate these points. A brief overview of the role of sample collection, processing and storage is given including some generic recommendations for maximising the reliability of subsequent analytical data. Using the examples of phytoestrogens and iodine the question of whether biomarkers can accurately reflect the intake of the dietary constituents of interest at the population level or at the individual level is considered. The relationship of the biomarker to the natural history of the disease is exemplified using the role of folate in neural tube defects. Finally, intakes of vitamin D and heterocyclic amines are used to illustrate the integration of biomarkers into epidemiological studies of prostate and colorectal cancer, respectively. It is concluded that biomarkers may provide a more accurate and objective measure of diet than estimates of current or usual intake but that this approach also has limitations. A combination of methods will probably prove to be most valuable and this approach is being taken in current large prospective studies.

Limitations of the single-cell gel electrophoresis assay to monitor apoptosis in U937 and HepG2 cells exposed to 7beta-hydroxycholesterol

The single-cell gel electrophoresis (comet) assay is a method which allows the detection of DNA strand breaks in individual cells. It has been suggested that the single cell gel electrophoresis assay, as an index of DNA fragmentation during cell death, may be applied to monitor apoptosis. The aim of the present study was to determine if the pattern of DNA fragmentation determined by the single cell gel electrophoresis assay can be used to discriminate between the mode of cell death in two cell lines (U937, a human monocytic blood cell line and HepG2, a human hepatocarcinoma cell line) which were treated with 30 microM 7beta-hydroxycholesterol (7betaOHC) over a 48 hr period. The single cell gel electrophoresis assay was compared with more established methods for the determination of apoptosis such as morphological examination, flow cytometry and DNA laddering. The percentage of maximally damaged nuclei as measured by the single cell gel electrophoresis assay was found to be similar at 48 hr in both U937 and HepG2 cells when treated with 7betaOHC. However, morphological examination, flow cytometry and DNA laddering techniques showed that 7betaOHC induced apoptosis in U937 cells but not in HepG2 cells. Thus, although the alkaline single cell gel electrophoresis assay detected DNA strand breaks occurring during cell death, these breaks were observed only when the process was fairly well advanced and a major part of the cells had lost membrane permeability. Therefore the present report demonstrates that the single cell gel electrophoresis assay, used in isolation, cannot accurately be used to distinguish between the mode of cell death induced by 7betaOHC in U937 cells (apoptosis), or HepG2 cells (cell lysis).

A ten year update on the marketing life cycle for hospital information technologies

This is a 1999 update of an original article based on 1989-90 data published in the Journal of Hospital Marketing. The adoption of hospital information technologies shows that most of these technologies were no longer in the innovator or early adopter stages. Infrastructure building technologies such as clinical information links, PC networking with the mainframe, MD links between doctors and hospital and E-mail showed the highest percentage of increase. Bar coding for inventory (transactional) also made great increases. Opinions on barriers to the adoption of hospital information technology are ranked and are studied by age of respondent, public vs. private hospitals, and job function.

Normal development of thymus in male and female mice requires estrogen/estrogen receptor-alpha signaling pathway

Estrogen receptors (ERs) are expressed in the thymus of both males and females, but their role in thymic development and function is unclear. To determine whether ERalpha plays a role in thymic function of either males or females, we compared thymuses of male and female wild-type (WT) and ERalpha knockout (alphaERKO) mice from birth to adulthood. Although thymic size was similar in both male and female WT and alphaERKO mice at birth (d 0), by postnatal d 5 and at all subsequent ages, both male and female alphaERKO mice had significant (30-55%) reductions in thymic weight. Morphometric analysis revealed a reduction in thymic medullary areas in adult alphaERKO mice compared with age-matched WT controls that paralleled thymic involution. There were changes in relative percentages of CD4+ and CD4+CD8+ T-cells, and large decreases (70-80%) in overall absolute numbers of CD4+ and CD4+CD8+ T-cells. Serum corticosterone and testosterone levels were not different in either neonatal or adult male WT or alphaERKO mice, and serum levels of 17beta-estradiol (E2) were similar in neonatal WT and alphaERKO males, indicating that increases in these thymolytic hormones are not responsible for the decreased thymic weight in alphaERKO males. Additionally, delayed-type hypersensitivity was significantly increased in male alphaERKO mice compared with WT mice. In summary, ERalpha deficiency does not inhibit initial differentiation or fetal thymic development, but the absence of ERalpha results in marked decreases in thymic size in both sexes during the postnatal period. These results are the first direct demonstration that the E2/ERalpha signaling system is necessary for maintenance of normal postnatal function of the female thymus gland. The similar results obtained in males demonstrate a role for the E2/ERalpha signaling system in the male thymus and emphasize that estrogens play a more critical role in the male than previously realized.

Exercise and neuroendocrine modulation of macrophage function

Like all immune cells, Mphi's cannot simply be viewed as individual cells, but as part of a complex network of cells and tissues that communicate in many different ways in an attempt to elicit an appropriate host response to immune and other challenges. Mphi's are important initial effector cells and are highly regulated by other cells (including T and B lymphocytes) and hormones produced by the sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis. Indeed, it may well be that stressors, including exercise, exert their regulatory influence over these cells by activating the SNS, HPA axis, or by influencing other tissues or cells. With this in mind, the overall objective of this review is to introduce and provide current information regarding the role of neuroendocrine factors in mediating exercise-induced changes in macrophage (Mphi) function. Under this broad objective this review will: 1) briefly discuss the cell biology of the Mphi and its role in host defense, 2) explore the potential regulatory influence of selected neuroendocrine hormones (glucocorticoids, catecholamines, growth hormone, prolactin, and beta-endorphin) that may potentially mediate exercise-induced changes in Mphi function, and 3) describe the effects of exercise on the functions of the Mphi.

Cytotoxicity, genotoxicity and oxidative reactions in cell-culture models: modulatory effects of phytochemicals

Much research effort has focused on the identification of phytochemicals in fruit and vegetables which exert beneficial effects. Our research examines modulatory effects of phytochemicals on cytotoxicity, genotoxicity and oxidative reactions in cell systems. Two examples of our studies are discussed. First, the potential beneficial effects of flavonoids are demonstrated. Flavonoids are reported to exhibit a wide variety of biological effects, including antioxidant and free-radical-scavenging activities. The aim of the study was to determine if flavonoids could protect against H2O2-induced DNA damage, as measured by the comet assay, in Caco-2 and HepG2 cells. Both cell lines were supplemented with increasing concentrations of myricetin, quercetin and rutin for 24 h followed by exposure to H2O2 (50 microM) for 30 min. Exposure to H2O2 for 30 min at 37 degrees C resulted in significant DNA damage and pre-incubation with the flavonoids before H2O2 exposure significantly (P <0.05) protected Caco-2 and HepG2 cells against H2O2-induced DNA damage. Secondly, we illustrate the use of cellular models to study oxysterol-induced toxicity. Oxysterols are generated during the cooking and processing of foods and may be produced endogenously by the oxidation of membrane lipids. Recent findings suggest that oxysterols may modulate cytotoxicity by exerting effects on the induction of apoptosis. 7beta-Hydroxycholesterol (7beta-OHC) and 25-hydroxycholesterol, both of which are commonly found in foods, were investigated for their abilities to induce apoptosis in a human monocytic blood cell line, U937, and in the human hepatoma cell line, HepG2 cells. U937 and HepG2 cells were incubated for up to 48 h with 30 microM oxysterol. 7beta-OHC induced apoptosis in U937 cells as measured by non-random DNA fragmentation, condensed and fragmented nuclei, and the generation of hypodiploid cells. In contrast, oxysterols may induce cell death by a different mechanism in the hepatoma cells, possibly by necrosis.

Intracellular mechanisms responsible for exercise-induced suppression of macrophage antigen presentation

In a previous study, we demonstrated that exhaustive exercise suppressed peritoneal macrophage antigen presentation (AP). In this study, we explored the intracellular mechanism(s) responsible for this suppression. Pathogen-free male BALB/c mice (8 +/- 2 wk) were randomly assigned to either home cage control (HCC) or exhaustive exercise stress (Exh, 18-30 m/min for 3 h/day) treatment groups. The mice underwent treatments for a period of 4 days during induced peritoneal thioglycollate inflammation. Elicited macrophages were harvested, purified, and incubated with chicken ovalbumin (C-Ova, 2. 5 and 10 mg/ml) for 18 h. After macrophages were washed, they were cocultured with C-Ova-specific T cells for 48 h at which time the supernates were harvested and analyzed via ELISA for interleukin (IL)-2 as an indication of macrophage AP. There was no significant (P > 0.05) difference in macrophage AP between cells fixed with paraformaldehyde vs. those that remained unfixed, suggesting that Exh did not affect production of soluble factors influencing macrophage AP (i.e., IL-1, IL-4, PGE(2)). The ability of macrophages to generate C-Ova immunogenic peptides was analyzed using FITC-labeled C-Ova, which shows fluorescence only when degraded intracellularly. There was a significant ( approximately 20%, P < 0. 05) suppression in fluorescence in the Exh compared with HCC, indicating a possible defect in the ability of macrophages from Exh to degrade C-Ova into immunogenic peptides. Macrophages were also incubated with C-Ova immunogenic peptide in a manner identical to that for native C-Ova. We found a similar suppression ( approximately 22-38%, P < 0.05) in macrophage AP using a C-Ova peptide when compared with native C-Ova in the Exh group, indicating reduced major histocompatibility complex (MHC) II loading and/or C-Ova-MHC II complex cell surface expression. In conclusion, these data indicate an intracellular defect in the macrophage antigen processing pathway induced by Exh.

Oxysterol-induced cell death in U937 and HepG2 cells at reduced and normal serum concentrations

BACKGROUND AND AIMS

Cholesterol oxidation products (oxysterols) are commonly found in foods of animal origin and are also produced endogenously in the body. Oxysterols are cytotoxic to certain cell lines and in some cases have been shown to induce apoptosis. The aim of this study was to investigate the effects of 7beta-hydroxy-cholesterol (7beta-OHC) and 25-hydroxycholesterol (25-OHC) on cytotoxicity and induction of apoptosis in U937 and HepG2 cells, treated in media containing either 2.5% foetal calf serum (FCS) or 10% FCS to examine the effect of increasing the cholesterol level.

METHODS

The cells were incubated for 24 and 48 h with 30 microM oxysterol. Viability was assessed by fluorescein diacetate/ethidium bromide staining and cell proliferation was determined by haemocytometer counting. Apoptosis was monitored by detection of DNA fragments (laddering) in 1.5% agarose gels. Cells with condensed or fragmented nuclei were identified by Hoechst 33342 staining. The percentage of cells with sub-G1 levels of DNA was measured by flow cytometry.

RESULTS

Treatment of U937 cells with 7beta-OHC, in contrast to 25-OHC, resulted in a decrease in cell viability and proliferation at 24 and 48 h (P <.01). 25-OHC and 7beta-OHC were both equally cytotoxic to the HepG2 cell line. 7beta-OHC induced DNA laddering and an increase in the percentage of condensed or fragmented nuclei at both time points and at both serum concentrations in the U937 cell line. 25-OHC induced faint laddering in the U937 cells after 48 h in reduced serum media and resulted in a small increase in percentage condensed or fragmented nuclei which was independent of time of oxysterol exposure and serum concentration. The percentage of condensed or fragmented nuclei was low in the HepG2 cell line and no laddering was observed under any of the conditions studied. Flow cytometric analysis showed that only 7beta-OHC treated U937 cells had an increased level of hypodiploid cells.

CONCLUSION

Both oxysterols appear to be equally cytotoxic to the HepG2 cell line. In U937 cells, 25-OHC is much less cytotoxic than 7beta-OHC. In addition, we have shown that 7beta-OHC induces apoptosis in U937 cells. 10% FCS displays a protective effect on cytotoxicity (as well as on 7beta-OHC induced apoptosis in U937 cells), although the data did not reach statistical significance.

Exercise suppresses macrophage antigen presentation

This study determined the effects of exercise on the ability of macrophages (Mphi) to present antigen to T cells. Pathogen-free male Balb/c mice (8 +/- 2 wk of age) were randomly assigned to either home cage control, moderate exercise (Mod; 18 m/min, 5% grade, 0.5 h/day), exhaustive exercise (Exh, 18-30 m/min, 3 h/day), or treadmill control groups. The mice underwent treatments for 4 days during peritoneal thioglycolate inflammation. Peritoneal Mphi were harvested, purified, and incubated with chicken ovalbumin (C-OVA; 0-10 mg/ml) for 18 h. Mphi were then cocultured with C-OVA-specific T cells for 48 h, and the supernatants were analyzed via ELISA for interleukin-2 as an indication of Mphi antigen presentation (AP). Exh exhibited suppressed ( approximately 25-34%) Mphi AP across a wide range of C-OVA doses when measured immediately, 3, and 24 h postexercise. In contrast, Mod had reduced Mphi AP only at 3 h postexercise. Mphi AP was also lower in the treadmill control (4-27%) compared with the home cage control group, but was significantly higher than Exh. The reduction in Mphi AP was not due to exercise-induced differences in Mphi number, percentage, or expression of intercellular adhesion molecule-1, B7-2, or major histocompatability complex II, molecules important in AP. In conclusion, our data lend evidence that may help explain the increased incidence of infection observed after prolonged exhaustive exercise or overtraining.

Preservation of comet assay slides: comparison with fresh slides

The single cell gel electrophoresis assay (comet assay) is an inexpensive, rapid and highly sensitive method for the determination of DNA damage, crosslinks, and alkaline-labile lesions in individual cells. A limitation of the procedure is that the microelectrophoretic gels must be scored rapidly as the comet configuration deteriorates on storage due to dehydration of the agarose and diffusion of DNA. The objectives of this study were firstly to evaluate drying regimes as rapid and simple methods of preservation of the microgels as close to their original fresh state as possible, and secondly to examine the effects of storage of the slides. Human hepatoma (HepG2) cells challenged for 30 min with hydrogen peroxide (H(2)O(2)) were used in the study. Microgel slides were prepared and evaluated immediately, or after drying with or without a methanol fixation step. Microgels that were dried at a variety of temperatures (22-50 degrees C) and re-hydrated did not differ in the values obtained for H(2)O(2)-induced DNA damage when compared to fresh samples. Samples could also be continually dried and re-hydrated over a period of up to 3 months with no obvious loss of information. In conclusion, drying of microgels represents a simple and inexpensive method of preserving comet assay slides.

Differential leukocytosis and lymphocyte mitogenic response to acute maximal exercise in the young and old

Despite the increasing use of exercise in the elderly as a means of improving muscle function, little is known regarding the effects of exercise on the senescent immune system.

PURPOSE

The purpose of this study was to determine the effects of acute maximal exercise on blood leukocyte numbers, leukocyte subsets, and the T cell mitogenic response in the elderly.

METHODS

Previously sedentary elderly (N = 33, 65.3 +/- 0.8 yr) and young (N = 14, 22.4 +/- 0.7 yr) subjects participated in a modified Balke maximal exercise treadmill test. Venous blood samples were collected pre-, immediately post-, and 20 min postexercise. Blood was analyzed for leukocyte counts, leukocyte subsets via immunofluorescence, and whole blood mitogenesis in response to various doses of mitogens.

RESULTS

Whereas VO2max was lower in the elderly, maximal RQ, age-predicted heart rates, and times to fatigue were not different, indicating that both groups achieved relative maximal exercise intensity. There were significant exercise-induced leukocytoses in both the elderly and young made up largely of a lymphocytosis and neutrophilia. The magnitude of the leukocytosis was lower in the elderly and failed to return to pre-exercise levels by 20 min postexercise. Acute maximal exercise increased CD8+ (153% vs 112% in young and old, respectively) and CD4+ (57% vs 22% in young and old, respectively) T cells when measured immediately postexercise. By 20 min postexercise, concentrations in the young were not significantly different from baseline, whereas CD8 cell number was still elevated in the old. The elderly had significantly higher percentages of memory (i.e., CD45RO+) and significantly lower percentages of naive (i.e., CD45RA+) CD4 and CD8 T cells pre-exercise, and the young and old recruited approximately equal numbers of CD8+ naive and memory cells to the blood in response to exercise. In contrast, the aged recruited significantly fewer numbers of CD4+ naive and transitional (CD45RA+RO+) cells. At most doses of Con A and PHA, the lymphoproliferative response was lower in the elderly subjects even though they had significantly higher numbers and percentages of CD3+ cells. Interestingly, immediately postexercise, young (but not old) subjects demonstrated reduced proliferative ability on a per CD3+ cell basis.

CONCLUSIONS

These data indicate that several blood leukocyte responses to maximal exercise stress are similar in the young and the old. However, the elderly demonstrate a less resilient leukocytosis and a different lympho-proliferative response following acute maximal exercise.

Effects of 6 months of moderate aerobic exercise training on immune function in the elderly

The purpose of this study was to determine the effects of 6 months of moderate aerobic exercise on age-dysregulated measures of T lymphocyte and natural killer (NK) cell number and function. Previously sedentary elderly (age = 65 +/- 0.8 years) subjects were randomly assigned to supervised 3 time/week exercise intervention group (EXC, n = 14) or flexibility/toning control group (FT-CON, n = 15). Fasting resting blood samples were drawn prior to and after the 6 month intervention. The EXC group exhibited a significant (P < 0.05) 20% increase in VO2 max, whereas the FT-CON group had a smaller non-significant (P = 0.07) increase (9%). Immune results revealed that, in general, changes in immune function in response to 6 months of exercise training at an average intensity of 52% heart rate reserve (HRR) were similar when compared to FT-CON who exercised at approximately 21% HRR. There were no intervention-induced changes in total white blood cell, neutrophil, lymphocyte, monocyte, eosinophil, or basophil blood counts. Furthermore, the percentage and number of CD3+, CD4+ and CD8+ T cells in the blood remained unchanged. There was a tendency for the percentage and number of CD4+ and CD8+ näive cells (CD45RA+) to increase and for CD4+ memory cells (CD45RO+) to decrease post-intervention, especially in FT-CON. Both groups exhibited a small intervention-induced increase in the T-cell proliferative response to mitogenic stimulation: the percentage change of which was higher in the EXC group at several doses of Con A. Unstimulated NK cell cytolysis versus K562 cells tended to increase (P < 0.1) in the EXC group with little change in FT-CON. We conclude that 6 months of supervised exercise training can lead to nominal increases in some measures of immune function, while not affecting others, in previously sedentary elderly.

Beta-carotene enhances hydrogen peroxide-induced DNA damage in human hepatocellular HepG2 cells

In this study, the alkaline version of the comet assay has been used to determine the effect of beta-carotene supplementation (10 microM) on peroxide-initiated free radical-mediated DNA damage in human HepG2 hepatoma cells. In supplemented cells, beta-carotene failed to afford any protection against hydrogen peroxide-induced DNA strand breaks. Indeed, levels of strand breaks in supplemented cells were significantly higher than in cells exposed to hydrogen peroxide alone, especially after a long incubation period. In contrast, beta-carotene afforded significant levels of protection against DNA strand breaks when cells were treated with tert-butyl hydroperoxide. In this case, the level of protection increased as supplementation continued.

Chronic exercise increases macrophage-mediated tumor cytolysis in young and old mice

In this study, we determined the effects of age and chronic treadmill running (16 wk; 5 days/wk; 45 min/day; 18-22 m/min) on resident peritoneal macrophage responsiveness to interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS) in young (6 mo) and aged (22 mo) male BALB/cByJ mice by measuring cytolytic ability and production of reactive nitrogen products. Macrophages (>90% Mac-3(+)) were incubated with various concentrations of IFN-gamma and LPS for 24 h. After washing, P815 tumor cells were utilized as targets in a 16-h 51Cr release assay. We found that aging resulted in a significant reduction in the ability of macrophages to respond to the highest doses of IFN-gamma and LPS and kill P815 cells (46 +/- 4 vs. 34 +/- 2% in young and old mice, respectively). Exercise training significantly increased macrophage cytolysis in both age groups (66 + 7 vs. 44 + 2% in young and old mice, respectively); this effect was larger in the young mice. Macrophages from young exercised mice also produced significantly (50-60%) more NO-2; there was a tendency for higher NO-2 in old exercisers. The inducible nitric oxide synthase (iNOS) inhibitor NG-monomethyl-L-arginine (L-NMMA) significantly reduced macrophage cytolysis and NO-2 production and completely abrogated exercise-induced increases in these measures. RT-PCR analysis revealed significantly higher iNOS mRNA levels in macrophages obtained from the exercise-trained mice and significantly lower iNOS mRNA in old compared with young mice. We conclude that aging reduces and exercise training increases the capacity of resident peritoneal macrophages to respond to IFN-gamma and LPS with increased tumor cytolysis. Enhanced iNOS gene expression and NO-2 production are likely the contributing mechanisms of the exercise-induced enhancement of cytolysis in young mice. While L-NMMA did block the exercise-induced increase in cytolysis, exercise did not increase NO-2 or iNOS gene expression in the old mice, indicating perhaps the contribution of other cytolytic mechanisms in old mice.

Exercise and cellular innate immune function

Epidemiological evidence suggests a link between the intensity of exercise and infectious and neoplastic disease. One likely way by which exercise exerts its effect on cancer and infection is by altering the function of the immune system. Cells of the innate immune system (i.e., macrophage [Mphi], natural killer [NK] cell, and polymorphonuclear neutrophils [PMN]) are first-line defenders against cancer and infectious disease by nature of their phagocytic, cytolytic, and antimicrobial properties. The purpose of this review is to define the role of cells of the innate immune system (i.e., Mphi, PMN, and NK cells) in infection and cancer, present current information regarding the effects of acute and chronic exercise on the quantification and functional activities of these cells, and briefly to discuss potential mechanisms as to how exercise affects these cells and describe how these changes may potentially affect susceptibility to infection and cancer. The effects of exercise on the number, functions, and characteristics of cells of the innate immune system are complex and are dependent several factors, including 1) the cell function or characteristic being analyzed; 2) the intensity, duration and chronicity of exercise; 3) the timing of measurement in relation to the exercise bout; 4) the dose and type of immunomodulator used to stimulate the cell in vitro or in vivo; and 5) the site of cellular origin. Further studies are needed to determine whether the exercise-induced changes in immune function alter incidence or progression of disease. Likewise, the mechanisms as to how exercise alters innate immune function are as yet unresolved.

Effects of maximal exercise on natural killer (NK) cell cytotoxicity and responsiveness to interferon-alpha in the young and old

We investigated the effects of a graded maximal exercise treadmill test on natural killer (NK) cell number, activity, and responsiveness to interferon-alpha (IFN-alpha) in young (22+/-0.7 yrs) and elderly (65+/-0.8 yrs) sedentary subjects. NK cell cytotoxicity (NKCC) was determined using Ficoll purified peripheral blood mononuclear cells (PBMCs) by a 51Cr release assay against NK-sensitive (K562) and NK-insensitive (Daudi) target cells at various effector:target (E:T) ratios before and immediately after exercise. PBMCs were incubated with rhu IFN-alpha (125 and 250u/10(6) PBMCs) or without for 2 hrs before addition to the 51Cr release assay. There were no differences in unstimulated NKCC against K562 or Daudi targets between the old and the young despite significantly (p=.01) higher percentages of CD56+ NK cells (21.1+/-2.3% in old vs 12.5+/-2.5% in young, pre-exercise). IFN-alpha increased NKCC versus both targets, and NK cells from old subjects were hyporesponsive to IFN-alpha stimulation; this was especially evident at low E:T ratios versus Daudi cells. Maximal exercise significantly increased (50-200%) unstimulated NKCC versus K562 and Daudi targets similarly in both young and old and increased the percentage of CD56+ cells in the PBMC fraction to 33.3+/-3.7% and 23.3+/-3.6% in old and young, respectively. We found a significant correlation between %CD56+ and basal NKCC versus K562s and Daudi cells in the young (i.e., r=.55; p=.02 vs K562s), but not the old (i.e., r=.20; p=.29 vs K562s) subjects. This indicates that, in the young, part of the exercise-induced increase in NKCC is due to an increase in NK cell number. Maximal exercise did not affect unstimulated per cell killing of K562s, but tended to increase per cell killing of Daudis. These results indicate that CD56+ cells from old subjects have an intrinsic defect in their ability to perform cytolysis and respond to IFN-alpha. Furthermore, a single bout of maximal exercise increases NKCC and CD56+ cell number similarly in both young and old subjects regardless of the target cell used.

Investigation of the potential genotoxicity of cholesterol oxidation products in two mammalian fibroblast cell lines

Cholesterol oxidation products (oxysterols) are generated during the cooking and processing of foods and may be produced endogenously in tissues and in the plasma membrane. A diverse range of biological functions have been ascribed to oxysterols, including atherogenicity, carcinogenicity, and mutagenicity, and in recent years concern has been expressed over the presence of oxysterols in food products. However, it is unclear whether oxysterols are capable of inducing genotoxic damage in cell culture systems. The aim of this study was to examine seven commonly occurring oxysterols (purity > 95%) for their cytotoxicity and ability to increase the frequency of DNA strand breaks and sister chromatid exchanges (SCE) in cells in culture. Two cell lines were employed in the study: Chinese hamster ovary (CHO) and Indian Muntjac (IM) fibroblasts. The 3-(4,5-dimethylthiozol-2-yl)-2,5-diphenyltetrazolium bromide assay, which is a measure of intracellular reductive metabolism based on the activity of mitochondrial dehydrogenases, was used as an index of cytotoxicity. The most cytotoxic oxysterols in constantly challenged CHO or IM cells (24-h exposure) proved to be 5 alpha-cholestane-3 beta,5,6 beta-triol and 25-hydroxy-cholesterol. The genotoxic potential of the oxysterols was assessed in CHO cells using the comet assay and IM cells using the SCE assay. The comet assay measures breaks in the DNA strand, whereas the exact mechanism of SCE formation is unclear but is believed to require DNA repair where genetic material becomes exchanged between the two sister chromatids. None of the oxysterols examined in this study affected baseline levels of DNA strand breaks or SCE relative to the negative control samples. This study indicates that, under the conditions used, the oxysterols investigated were not genotoxic.

A new barrier-free burn center

This article describes a barrier-free burn center that is accessible to persons with disabilities and that complies with Title III of the Americans with Disabilities Act. The burn center has 3 separate components: patient rooms, patient support facilities, and staff support facilities. Thirteen rooms are used to care for 16 patients. Two of the 13 rooms are accessible to people with disabilities. These 2 rooms have wide doors that permit a wheelchair to pass through, and they have enough clear floor space for a wheelchair to make a 180 degrees turn. The rooms have a sink that is accessible from a wheelchair. The bathrooms have large, clear floor spaces that allow for the turning of a wheelchair, elevated toilets, grab bars, and showers that permit wheelchair access. Special wheelchairs that provide easier shower and commode access are available. The patient support services feature a large hydrotherapy room that contains a table-shower system that allows a person in a wheelchair to gain access to both sides of the shower table. A tub room has been constructed to provide compact patient bathing and hydromassage, and it is also accessible to people in wheelchairs. The staff support services include a locker room that has a shower accessible to people with disabilities so that staff members with mobility disorders can work in the burn center. Grade II braille writing marks all of the signs that designate the permanent rooms and spacing in the burn center and in the contiguous common use areas. The common use area has a restroom accessible to people with disabilities and a waiting room with a telephone communications system for people with mobility disorders or mobility impairment.

"Scientific basis of wound closure techniques." Evaluation of a new training program

A formal training program in wound repair entitled "Scientific Basis of Wound Closure Techniques" has been developed and is accredited by the Dannemiller Memorial Educational Foundation. This course is now available at no cost to medical schools, residencies, and continuing education programs for graduate physicians. A manual with its complementing videotape allow the course participant to gain the necessary psychomotor skills to repair wounds. Evaluation of the course taken by third-year medical students and first-year residents demonstrates a high level of satisfaction. After instituting the course, there was a noticeable change in the types of barriers, instruments, and wound closure techniques practiced in our emergency department.

Magnetic resonance imaging in the early diagnosis of group A beta streptococcal necrotizing fasciitis: a case report

Early diagnosis of invasive group A beta streptococcal (GABS) infection has been achieved in a patient using magnetic resonance imaging (MRI) complemented by needle aspiration. Life-saving treatments of GABS infection that include immediate surgical debridement along with the administration of i.v. antibiotics, gamma globulin, and hyperbaric oxygen were then implemented successfully to prevent the development of streptococcal toxic shock syndrome. While MRI is valuable in making early diagnosis of GABS, it should not delay surgical intervention.

Exercise and resistance to neoplasia

Epidemiological evidence has revealed an inverse relationship such that increased physical activity as measured directly subjective recall, job classification, former athletic status, or indirectly by physical fitness is associated with decreased incidence and (or) mortality rates for various cancers. The relationship appears strongest for colon cancer and female estrogen-dependent cancers of the breast, ovary, and endometrium. While some epidemiological studies have controlled for numerous confounding variables such as smoking, body mass index, and percent body fat, it is still difficult to ascertain whether physical activity exerts an independent effect on cancer above and beyond that associated with an improved lifestyle and numerous other potential confounding variables. Experimental studies performed in animals suggests that chronic exercise, especially when performed prior to tumorigenesis, can retard, delay, or prevent the incidence, progression, or spread of experimental tumors. There is also limited animal evidence suggesting that exercise may help ameliorate cancer cachexia. Exercise or physical activity may contribute to a reduction in site-specific cancers by different physiological mechanisms. Some purported mechanisms include decreased lifetime exposure to estrogen or other hormones, reduced body fat, enhanced gut motility, improved anti-oxidant defenses, and stimulation of anti-tumor immune defenses. Unfortunately, most animal studies have failed to account for plausible biological mechanisms as to how exercise might influence cancer. In addition, the exercise or activity dosage required to provide optimal protection from cancer is unclear. Interpretation of epidemiological studies is hampered by the numerous and sometimes inaccurate assessments of physical activity. Likewise, many animal studies have utilized unrealistic exercise protocols. Clearly, more research is needed to define appropriate activity or exercise dosages definitively and to explore the mechanism(s) by which exercise helps protect against cancer. Nevertheless, moderate exercise appears to be a safe and effective means of aiding in the prevention of cancer and should be adopted by the public in addition to other prudent behavioral practices such as proper diet. More research needs to be performed regarding the effects of exercise or physical activity on those who already have cancer to determine if exercise improves their prognosis.