Predictors of prostate cancer-specific mortality in elderly men with intermediate-risk prostate cancer treated with radiation therapy

9543

Background: To identify clinical factors associated with prostate cancer-specific mortality (PCSM), adjusting for co-morbidity, in elderly men with intermediate-risk prostate cancer treated with brachytherapy alone or in conjunction with external beam radiation therapy (EBRT). Methods: The study cohort comprised 1,978 men of median age 71 (interquartile range [IQR], 66–75) years with intermediate-risk prostate cancer (Gleason score 7 with PSA 20 ng/mL or less and tumor category T2c or less). Fine and Gray's multivariable competing risks regression was used to assess whether presence of cardiovascular disease (CVD), age, treatment, year of brachytherapy, PSA level, or tumor category were associated with the risk of PCSM. Results: After a median follow up of 3.2 (IQR, 1.7 - 5.4) years, 15 men were observed to experience PCSM. The presence of CVD was significantly associated with a decreased risk of PCSM (AHR 0.20, 95% CI 0.04 - 0.99, P = 0.05), whereas an increasing PSA level was significantly associated with an increased risk of PCSM (AHR 1.14, 95% CI 1.02 - 1.27, P = 0.02). In the absence of CVD, cumulative incidence estimates of PCSM were higher (P = 0.03) in men with PSA levels above as compared to the median PSA level (7.3 ng/mL) or less; however, in the setting of CVD there was no difference (P = 0.27) in these estimates stratified by the median PSA level (6.9 ng/mL). Conclusions: Detection of intermediate-risk prostate cancer in elderly men without CVD at lower PSA levels is associated with a lower risk of PCSM; this risk reduction is not observed in men with known CVD.

[Table: see text]

No significant financial relationships to disclose.

Efficacy of current growth hormone treatments and future therapies

Despite huge advances having been made in some areas of medicine, options for the treatment of GH deficiency (GHD) have remained constant since the introduction of GH in the 1950s. Several initiatives have been introduced to improve the understanding and treatment of GHD with GH, including the long-term Hypopituitary Control and Complications Study (HypoCCS) and the issuance of clinical guidelines. This article considers the impact of these initiatives and considers new treatment options which will potentially provide important future benefits for GHD patients.

Is the reduction of lower-body subcutaneous adipose tissue associated with elevations in risk factors for diabetes and cardiovascular disease?

AIMS/HYPOTHESIS

Since the accumulation of lower-body subcutaneous adipose tissue (LBSAT) is associated with decreased cardiometabolic risk, we evaluated whether reductions in LBSAT independent of changes in visceral AT (VAT) and abdominal SAT are associated with elevations in diabetes and cardiovascular disease risk factors.

METHODS

Overweight and obese men (n = 58) and premenopausal women (n = 49) with elevated cardiometabolic risk underwent 3 months of diet and/or exercise induced weight-loss treatment; regional body composition assessment by magnetic resonance imaging (MRI); and cardiometabolic risk assessment, including an OGTT.

RESULTS

After control for potential confounders, reductions in VAT, abdominal SAT and LBSAT were all associated with improvements in selective cardiometabolic risk factors, including fasting glucose levels, lipid status and OGTT glucose and insulin. Independent of changes in the other AT depots, reductions in VAT and abdominal SAT, but not LBSAT, remained associated with improvement in fasting glucose levels, glucose tolerance and lipid status.

CONCLUSIONS/INTERPRETATION

Among overweight and obese adults with increased cardiometabolic risk, the selective reduction of LBSAT is not associated with elevations in risk factors for diabetes and cardiovascular disease. Thus, the reduction of excess AT conveys health benefit regardless of origin.

Does the relationship between waist circumference, morbidity and mortality depend on measurement protocol for waist circumference?

There is currently no consensus regarding the optimal protocol for measurement of waist circumference (WC), and no scientific rationale is provided for any of the WC protocols recommended by leading health authorities. A panel of experts conducted a systematic review of 120 studies (236 samples) to determine whether measurement protocol influenced the relationship of WC with morbidity of cardiovascular disease (CVD) and diabetes and with mortality from all causes and from CVD. Statistically significant associations with WC were reported for 65% (152) of the samples across all outcomes combined. Common WC protocols performed measurement at the minimal waist (33%), midpoint (26%) and umbilicus (27%). Non-significant associations were reported for 27% (64) of the samples. Most of these protocols measured WC at the midpoint (36%), umbilicus (28%) or minimal waist (25%). Significant associations were observed for 17 of the remaining 20 samples, but these were not significant when adjustment was made for covariates. For these samples, the most common WC protocols were the midpoint (35%) and umbilicus (30%). Similar patterns of association between the outcomes and all WC protocols were observed across sample size, sex, age, race and ethnicity. Our findings suggest that WC measurement protocol has no substantial influence on the association between WC, all-cause and CVD mortality, CVD and diabetes.

Beta-alanine and the hormonal response to exercise

The effect of 30 days of beta-alanine supplementation (4.8 g per day) on resistance exercise performance and endocrine changes was examined in eight experienced resistance-trained men. An acute resistance exercise protocol consisting of 6 sets of 12 repetitions of the squat exercise at 70 % of one-repetition maximum (1-RM) with 1.5 minutes of rest between sets was performed before and after each supplemental period. Blood draws occurred at baseline (BL), immediate (IP), 15-minutes (15P) and 30-minutes (30P) postexercise for growth hormone, testosterone and cortisol concentrations. A 22 % (p < 0.05) difference in total number of repetitions performed at the end of 4 weeks of supplementation was seen between beta-alanine (BA) and placebo (PL), and Delta mean power was greater in BA (98.4 +/- 43.8 w) vs. PL (7.2 +/- 29.6 w). Growth hormone concentrations were elevated from BL at IP and 15P for both groups, while cortisol concentrations were greater than BL at all time points for both BA and PL. No group differences were noted. No change from BL was seen in testosterone concentrations for either group. Results indicate that four weeks of beta-alanine supplementation can significantly improve muscular endurance during resistance training in experienced resistance-trained athletes. However, these performance gains did not affect the acute endocrine response to the exercise stimulus.

Platelet-derived growth factor: its potential roles in wound healing, atherosclerosis, neoplasia, and growth and development

Platelet-derived growth factor (PDGF) has been found to be derived not only from platelets that have been induced to release their contents, but also from a number of transformed cells (including cells transformed by both DNA and RNA viruses, spontaneous transformation, and cells from various human tumours), from activated macrophages, from embryonic rat aortic smooth muscle cells, and from rat aortic smooth muscle cells derived from experimentally induced intimal proliferative lesions. The studies discussed demonstrate the potential role of platelets and macrophages in atherosclerosis and in wound repair, and indicate the ability of anti-PDGF IgG to inhibit proliferative responses in vitro. With the demonstration that the transforming protein derived from the oncogene from the simian sarcoma virus is highly homologous with PDGF, it was possible to show that a number of transformed cells secrete PDGF and show markedly decreased binding of PDGF. The same is true for embryonic rat aortic smooth muscle cells and for cells from experimentally induced proliferative lesions in the rat carotid artery. All these findings point to the role of PDGF in the formation of these lesions and can be correlated with the capacity of the cells noted above, as well as injured endothelial cells, to secrete PDGF or PDGF-like molecules. The biological significance of these observations is discussed and a model for atherogenesis is proposed.

Self-reported symptom burden; outcome in 418 patients from the Newcastle Vasovagal (Neurocardiogenic) cohort

BACKGROUND

Natural history of Vasovagal syndrome (Neurocardiogenic; NCS) is unclear.

AIM

To examine symptoms in a large cohort with head up tilt diagnosed NCS.

METHODS

Questionnaires were posted to 485 patients with NCS. Data included demographic details, age at referral, presenting and on-going symptoms (syncope, dizziness and falls), symptom frequency (daily, weekly, monthly) and burden.

RESULTS

A total of 418 questionnaires were returned (response rate 86%), 67% female. Median age at first presentation 60 (range 10-90), with men younger (54 vs. 63; P = 0.01). Seventy percent presented with syncope. Median follow-up 5 years (1-8). At follow-up 147(35%) were asymptomatic. The asymptomatic group was older (73 vs. 65; P = 0.0001) with more males (39 vs. 29%; P = 0.04). Those presenting with syncope were more likely to be symptom-free than those with dizziness (P < 0.02). Symptom frequency was greatest for those reporting dizziness at follow-up (P < 0.05). Sixty (22%) reported symptoms never preventing activities [predominantly those reporting dizziness (P = 0.04)]. Although there was a significant reduction of symptoms overall, there was a significant increase in those reporting dizziness only (P < 0.0001).

CONCLUSION

Of those with NCS, 35% will be symptom-free at 5 years regardless of presenting symptom or treatment received.

Survival and clinical outcome of SB Charite III disc replacement for back pain

Between January 1990 and December 2000 we carried out 226 SB Charité III disc replacements for lumbar disc degeneration in 160 patients. They were reviewed at a mean follow-up of 79 months (31 to 161) to determine the clinical and radiological outcome. The clinical results were collected by an independent observer, who was not involved in patient selection, treatment or follow-up, using a combination of outcome measures, including the Oswestry Disability Index. Pain was recorded using a visual analogue score, and the most recent radiographs were reviewed. Survival of the device was analysed by the Kaplan-Meier method and showed a cumulative survival of 35% at 156 months when radiological failure was taken as the endpoint. The mean improvement in the Oswestry disability index scores after disc replacement was 14% (6% to 21%) and the mean improvement in the pain score was 1.6 (0.46 to 2.73), both falling below the clinically significant threshold. Removal of the implant was required in 12 patients, four because of implant failure. These poor results indicate that further use of this implant is not justified.

Ineffectiveness of rosiglitazone therapy in Nelson's syndrome

BACKGROUND

Peroxisome proliferator-activated receptor (PPAR)-gamma agonists have been proposed as therapy to lower plasma ACTH in Cushing's disease. Cyclical secretion of ACTH may, however, explain some of the responses seen. Patients with Nelson's syndrome have persistently high levels of ACTH and may be a better model for examining new therapies to elevated ACTH levels.

OBJECTIVE

The objective of the study was to assess whether high-dose rosiglitazone therapy reduces circulating ACTH levels in Nelson's syndrome, a model of ACTH hypersecretion for which no established medical therapy exists.

DESIGN

The design was an open-label, prospective, nonrandomized study over 14 wk.

SETTING

The study was conducted at a university teaching hospital.

PATIENTS

Six patients with Nelson's syndrome participated in the study.

METHODS

Patients were assessed at -2, 0, 4, 8, and 12 wk. Rosiglitazone 12 mg/d was administered between 0 and 8 wk. PPAR-gamma immunoreactivity was assessed in pathological tissue.

OUTCOME MEASURE

Plasma ACTH was measured before (0830 h) and 120 min after morning dosing with hydrocortisone (HC).

RESULTS

One female withdrew prior to commencing therapy for personal reasons. There was no evidence that ACTH levels changed over time (P = 0.864). The average ACTH level was 1187 ng/liter (95% confidence interval 928-1446) for patients before the HC dose and 432 ng/liter (95% confidence interval 172-692) after the HC dose. PPAR-gamma immunoreactivity was positive in three ACTH-secreting tumors available.

CONCLUSIONS

Rosiglitazone 12 mg/d did not change circulating ACTH over time, despite PPAR-gamma receptor expression in the tumor tissue. However, this does not preclude the possibility that other patients may respond or that higher doses of rosiglitazone or more potent agonists might prove useful treatment.

Natural history of morbid obesity without surgical intervention

BACKGROUND

To study the mortality among morbidly obese patients qualifying for bariatric surgery. Mortality from bariatric surgery for morbid obesity has been widely reported; however, little is known about the mortality in morbidly obese patients who defer surgery.

METHODS

Consecutive patients evaluated for bariatric surgery with an initial encounter between 1997 and 2004 were identified. The Social Security Death Index and office records were used to identify mortality through 2006. We conducted telephone interviews to determine whether the 305 patients who did not undergo bariatric surgery at our institution had undergone the surgery elsewhere. Using Cox proportional hazards models, we compared the mortality in patients undergoing surgery with that of those who did not. To evaluate bias resulting from missing data, we conducted analyses assuming that all patients with missing data had (1) undergone surgery and (2) not undergone surgery.

RESULTS

A total of 908 patients underwent bariatric surgery (880 patients at our institution and 28 patients elsewhere). A total of 112 patients did not undergo surgery. Data regarding surgery on 165 patients could not be obtained. The mortality in those patients who did not undergo surgery was 14.3% compared with 2.9% for those who did undergo surgery. Adjusting for age, gender, and body mass index, patients who had undergone surgery had an 82% reduction in mortality (hazard ratio 0.18, 95% confidence interval 0.09-0.35, P <.0001). Sensitivity analysis, assuming that all patients with missing data received surgery resulted in an 85% mortality reduction (P <.001) and assuming that patients did not receive surgery resulted in a 50% mortality reduction (P = .04).

CONCLUSIONS

Mortality among morbidly obese patients without surgery was 14.3% during the study period. Surgical intervention offered a 50%-85% mortality reduction benefit.

In vitro and in vivo pharmacology of synthetic olivetol- or resorcinol-derived cannabinoid receptor ligands

BACKGROUND AND PURPOSE

We have previously reported the development of CB-25 and CB-52, two ligands of CB1 and CB2 cannabinoid receptors. We assessed here their functional activity.

EXPERIMENTAL APPROACH

The effect of the two compounds on forskolin-induced cAMP formation in intact cells or GTP-gamma-S binding to cell membranes, and their action on nociception in vivo was determined.

KEY RESULTS

CB-25 enhanced forskolin-induced cAMP formation in N18TG2 cells (EC50 approximately 20 nM, max. stimulation = 48%), behaving as an inverse CB1 agonist, but it stimulated GTP-gamma-S binding to mouse brain membranes, behaving as a partial CB1 agonist (EC50 =100 nM, max. stimulation = 48%). At human CB1 receptors, CB-25 inhibited cAMP formation in hCB1-CHO cells (EC50 = 1600 nM, max. inhibition = 68% of CP-55,940 effect). CB-52 inhibited forskolin-induced cAMP formation by N18TG2 cells (IC50 = 450 nM, max. inhibition = 40%) and hCB1-CHO cells (EC50 = 2600 nM, max. inhibition = 62% of CP-55,940 effect), and stimulated GTP-gamma-S binding to mouse brain membranes (EC50 = 11 nM, max. stimulation approximately 16%). Both CB-25 and CB-52 showed no activity in all assays of CB2-coupled functional activity and antagonized CP55940-induced stimulation of GTP-gamma-S binding to hCB2-CHO cell membranes. In vivo, both compounds, administered i.p., produced dose-dependent nociception in the plantar test carried out in healthy rats, and antagonised the anti-nociceptive effect of i.p. WIN55,212-2. In the formalin test in mice, however, the compounds counteracted both phases of formalin-induced nociception.

CONCLUSIONS AND IMPLICATIONS

CB-25 and CB-52 behave in vitro mostly as CB1 partial agonists and CB2 neutral antagonists, whereas their activity in vivo might depend on the tonic activity of cannabinoid receptors.

Increased late toxicity in 12–20 year survivors of germ cell tumors (GCT)

4509

Background: There is extensive literature on occurrence of late effects of cisplatin-based chemotherapy, but it comes from centers of excellence and may reflect case selection or ascertainment biases. Funded by the NIH SEER Program and the Lance Armstrong Foundation, we studied community-based late outcomes via identification of cases from the Los Angeles SEER Tumor Registry and comparison with a control group. Methods: We identified 951 patients treated in Los Angeles County through the records of the L.A. SEER Cancer Registry/Cancer Surveillance Program (CSP) for 1983–1987, giving a minimum follow-up of 12 years. Consent was obtained from physician of record and forms sent to the patients, requesting information about a broad range of demographic, treatment-related and psycho-social issues. In addition, patients were asked to provide a “control”, a friend of approximately the same age at time of diagnosis, known to the patient before diagnosis and known not to have a history of testis cancer. Questionnaires were also sent to controls, to allow data comparison with patients. Anticipated initial difficulties included mobility of young males and invalid addresses. This occurred in > 50% of cases, and we used a planned strategy for acquisition through State agencies, Department of Motor Vehicles, etc. Results: Surveys were returned by 298 cases and 67 control subjects, and 35 patients refused. In 1983–87, success rates were lower, and 142 patients had died. An unexpected problem was reluctance or inability of subjects to identify friends of comparable age to provide a control population. Differences in groups are summarized in the Table. Conclusions: Long term survivors with GCT have an excess of late toxicity, including cardiovascular, neurological, hematologic, musculoskeletal and neoplastic problems, which increase with time. These data should assist in design of surveillance protocols.

[Table: see text]

No significant financial relationships to disclose.

Linking age-related changes in skeletal muscle mass and composition with metabolism and disease

Skeletal muscle (SM) plays a central role in many biological functions, such as movement and metabolism, and alterations in SM mass and composition can have a marked influence on health and disease. The purpose of this review was to examine and characterize age-related changes in SM mass and composition and to link these changes to corresponding changes in metabolism and disease. It can be concluded from several studies that SM mass decreases with advancing age in both men and women. The age-related reduction in SM, also known as sarcopenia, is related to a corresponding reduction in SM strength, and if left untreated, sarcopenia may lead to functional impairment and physical disability. An emerging body of evidence also suggests that age-related changes in the composition of SM, particularly the accumulation of lipids within SM fibers, may lead to metabolic disorders such as insulin resistance.

Advances in the application of imaging methods in applied and clinical physiology

Application of computed tomography (CT) and magnetic resonance imaging (MRI) represents one of the most important advances in the history of human body composition research. Independently, these methods have been used to significantly advance our understanding of the complex relationships between human body composition and disease. They are the methods of choice for calibration of field methods designed to measure adipose tissue and skeletal muscle in vivo, and are the only procedures available for measurement of internal tissues and organs. More recently, both methods have been employed to measure the quality of various tissues including skeletal muscle and hepatic tissue. These recent advances in the use of CT and MRI in body composition research are discussed with a focus on clinical applications.

Transcriptional targeting of dendritic cells for gene therapy using the promoter of the cytoskeletal protein fascin

Strong cell-type-specific promoters are basic tools in gene therapy allowing for novel applications and focused strategies by transcriptionally targeting gene expression to selected cells. In immunotherapy, dendritic cells (DC) are of central importance, since they represent the principal inducers of immune responses. Here we describe isolation and use of the promoter of the murine actin-bundling protein fascin to target transcriptionally gene expression to cutaneous DC. Using the reporter gene enhanced green fluorescent protein (EGFP), we demonstrate that the fascin promoter mediates a strong antigen expression that is restricted to mature DC. DNA vaccination with antigen-encoding expression vectors under control of the fascin promoter using a gene gun resulted, consistently, in limited antigen expression by few directly transfected DC. Nevertheless, nearly as many antigen-specific CD8+ T cells directed against the encoded antigens EGFP and beta-galactosidase, respectively, were induced as with expression constructs under control of the ubiquitously expressed CMV promoter. This result impressively underlines the pivotal role of directly transfected DC in DNA vaccination. Immunization using the fascin promoter induced markedly lower levels of antigen-specific antibodies following single or repeated immunization. Thus, our DC-targeted DNA vaccination approach induces qualitatively distinct, predominantly cellular immune responses and provides new opportunities for immunotherapy.

Cardiorespiratory fitness is associated with diminished total and abdominal obesity independent of body mass index

OBJECTIVE

To determine whether, for a given body mass index (BMI), men and women with high cardiorespiratory fitness (HIGH CRF) have lower waist circumference (WC), sum of trunk skinfolds (SUM2) and sum of five skinfolds (SUM5), by comparison to those with LOW CRF.

DESIGN

Observational cohort study.

SETTING

1981 Canada Fitness Survey (CFS).

PARTICIPANTS

A total of 3719 men and 3854 women 20-59 y of age from the 1981 CFS for whom anthropometric and physical fitness measures were available.

MAIN OUTCOME MEASURES

BMI, waist circumference, skinfolds, cardiorespiratory fitness.

RESULTS

For a given BMI, men and women in the HIGH CRF group had lower WC, SUM2 and SUM5 by comparison to those with LOW CRF (P<0.001). A significant main effect for CRF group remained for SUM2 in both men (P=0.0001) and women (P=0.007), after statistical control for the effects of extremity fat. In women, but not men, there were significant interaction effects for WC (P=0.0023) and SUM5 (P=0.01), indicating that the difference between the LOW CRF and HIGH CRF groups increased with increasing BMI.

CONCLUSIONS

HIGH CRF is associated with lower levels of total and abdominal obesity for a given BMI by comparison to those with LOW CRF, independent of gender. This finding suggests a mechanism by which exercise attenuates the health risks attributed to obesity as measured by BMI. It is suggested that the routine measurement of WC and CRF would substantially improve the ability to identify those at health risk.

Medium- versus long-chain triglycerides for 27 days increases fat oxidation and energy expenditure without resulting in changes in body composition in overweight women

OBJECTIVE

To determine the effects of long-term consumption of medium chain (MCT) versus long chain triglycerides (LCT) on energy expenditure (EE), substrate oxidation and body composition.

HYPOTHESIS

MCT consumption will not result in greater EE, substrate oxidation, and body weight loss compared with LCT consumption.

RESEARCH METHODS AND PROCEDURES

Seventeen healthy obese women participated in this randomized, crossover inpatient trial. Meals were prepared and consumed on site for two periods of 27 days. Diets containing 40% of energy as fat, with treatment fat comprising 75% of the total fat, were designed to supply each subject with their individual weight-maintaining energy needs. The MCT diet contained 67% of treatment fat as MCT oil (49% octanoate, 50% decanoate) whereas the LCT diet contained exclusively beef tallow as treatment fat. Body composition was assessed by magnetic resonance imaging (MRI) on day 1 and 28 of each phase while energy expenditure was measured on day 2 and 27.

RESULTS

Changes in total and subcutaneous adipose tissue volumes following consumption of MCT and LCT were not different (-0.61+/-0.38 l vs -0.54+/-0.48 l and -0.58+/-0.35 l vs -0.48+/-0.40 l, respectively). Average EE and fat oxidation were greater (P<0.05) during MCT than LCT consumption (0.95+/-0.019 vs 0.90+/-0.024 kcal/min, respectively, for EE and 0.080+/-0.0026 vs 0.075+/-0.0022 g/min, respectively for fat oxidation).

DISCUSSION

These results show that long-term consumption of MCT enhances EE and fat oxidation in obese women, when compared to LCT consumption. The difference in body composition change between MCT and LCT consumption, although not statistically different, was consistent with differences predicted by the shifts in EE. It can be concluded that substitution of MCT for LCT in a targeted energy balance diet may prevent long-term weight gain via increased EE.

Insulin resistance but not visceral adipose tissue is associated with plasminogen activator inhibitor type 1 levels in overweight and obese premenopausal African-American women

OBJECTIVE

To compare plasma plasminogen activator inhibitor type 1 (PAI-1) levels and to examine the association of PAI-1 with visceral adiposity and other components of the metabolic syndrome in overweight and obese premenopausal African-American (AA) and Caucasian (CC) women.

DESIGN

Cross-sectional study.

SUBJECTS

33 CC and 23 AA healthy, overweight and obese, premenopausal women (age 19-53 y, body mass index 28.1-48.9 kg/m(2)).

MEASUREMENTS

Body mass index, sagittal diameter, waist circumference, percentage body fat, visceral and subcutaneous adipose tissue (by anthropometry, magnetic resonance imaging (MRI), and bioelectric impedance techniques), PAI-1, leptin, lipids, glucose, insulin, and insulin resistance (by HOMA IR).

RESULTS

AA women had lower triglyceride levels and less visceral adipose tissue (VAT) volume than CC despite similar BMI. PAI-1 levels were not significantly different in the two groups. Insulin resistance was associated with PAI-1 in both groups but only in CC women were VAT, triglyceride, HDL cholesterol and blood pressure related to plasma PAI-1 levels. Multiple regression analysis showed that VAT in CC and insulin resistance in AA were independent predictors of PAI-1.

CONCLUSION

VAT is significantly associated with circulating PAI-1 levels in overweight and obese CC but not AA premenopausal women.

Activation of metalloproteinases and their association with integrins: an auxiliary apoptotic pathway in human endothelial cells

Anchorage of cells to the extracellular matrix and integrin-mediated signals play crucial roles in cell survival. We have previously shown that during growth factor deprivation-induced apoptosis in human umbilical vein endothelial cells (HUVECs), key molecules in focal adhesions and adherens junctions are cleaved by caspases. In this study we provide evidence for a selective upregulation of cell-associated matrix metalloproteinases (MMPs). We observe a physical association of MMP2 with beta1 and alphav integrins, which increased three- to fourfold during apoptosis and is dependent upon integrin beta1 levels and activation state. Both enforced activation of beta1 integrin by a specific antibody and inhibition of MMPs protect HUVECs from apoptosis. We hypothesize that, prior to the commitment to apoptosis, 'inside-out' signals initiated by the apoptotic stimulus alter cell shape together with the activation states and/or the availability of integrins, which promote matrix-degrading activity around dying cells. This 'auxiliary' apoptotic pathway may interrupt ECM-mediated survival signaling, and thus accelerate the efficient execution of the cell death program.

MMP9 production by human monocyte-derived macrophages is decreased on polymerized type I collagen

The production of matrix metalloproteinases (MMPs), such as MMP9, by macrophages may be a critical factor in the rupture of unstable atherosclerotic plaques and aortic aneurysms. Therefore, we studied the role of matrix and soluble cytokines in the regulation of monocyte/macrophage expression of MMP9. Although freshly isolated monocytes synthesize little MMP9, cells cultured on tissue-culture plastic differentiate into macrophages and synthesize maximal amounts of MMP9. Differentiated macrophages cultured on plastic are unresponsive to further stimulation by interleukin 1beta, tumor necrosis factor alpha, or platelet-derived growth factor BB. In contrast, monocytes cultured on polymerized collagen synthesize much less MMP9 than cells cultured on plastic and demonstrate a more than three-fold increase in MMP9 synthesis in response to interleukin 1beta, tumor necrosis factor alpha, and platelet-derived growth factor BB. To determine whether the physical state of the collagen was critical for the decrease in basal synthesis of MMP9, monocytes were cultured in suspension for 5 days to allow differentiation and then seeded onto monomer or polymerized collagen. Synthesis of MMP9 was significantly decreased in cells on polymerized collagen and modestly increased in macrophages seeded on monomer collagen. These results suggest that MMP9 synthesis by macrophages in the vessel wall may be under negative control by native, polymerized collagen and that disruption of this native conformation could increase MMP9 production. In addition, cells in contact with the collagen matrix are potentially more responsive to soluble mediators such as platelet-derived growth factor, interleukin 1beta, and tumor necrosis factor alpha.

ADAM15 overexpression in NIH3T3 cells enhances cell-cell interactions

ADAM15 is a member of the family of metalloprotease-disintegrins that have been shown to interact with integrins in an RGD- and non-RGD-dependent manner. In the present study, we examined the effects of ADAM15 overexpression on cell-matrix and cell-cell interactions in NIH3T3 cells. Tetracycline-regulated ADAM15 overexpression in NIH3T3 cells leads to an inhibition of migration on a fibronectin-coated filter in a Boyden chamber assay and in a scratch wound model. The effects of ADAM15 overexpression on cell migration are not due to changes in matrix attachment or to the lack of extracellular signal-regulated kinase signaling response to PDGF or fibronectin. However, a decrease in monolayer permeability with ADAM15 overexpression and altered cell morphology suggest a possible increase in cell-cell interaction. Analysis of adhesion of NIH3T3 cells to a polyclonal population of cells retrovirally transduced to overexpress ADAM15 demonstrates a 45% increase in cell adhesion, compared with enhanced green fluorescent protein-expressing control cells. In addition, we demonstrate localization of HA-epitope-tagged ADAM15 to cell-cell contacts in an epithelial cell line that forms extensive cell-cell contact structures. Thus, overexpression of ADAM15 in NIH3T3 cells appears to enhance cell-cell interactions, as suggested by decreased cell migration, altered cell morphology at the wound edge, decreased monolayer permeability, and increased cell adhesion to monolayers of cells expressing ADAM15 by retroviral transduction.

Caffeine ingestion decreases glucose disposal during a hyperinsulinemic-euglycemic clamp in sedentary humans

The purpose of this investigation was to examine the effect of caffeine (an adenosine receptor antagonist) on whole-body insulin-mediated glucose disposal in resting humans. We hypothesized that glucose disposal would be lower after the administration of caffeine compared with placebo. Healthy, lean, sedentary (n = 9) men underwent two trial sessions, one after caffeine administration (5 mg/kg body wt) and one after placebo administration (dextrose) in a double-blind randomized design. Glucose disposal was assessed using a hyperinsulinemic-euglycemic clamp. Before the clamp, there were no differences in circulating levels of methylxanthines, catecholamines, or glucose. Euglycemia was maintained throughout the clamp with no difference in plasma glucose concentrations between trials. The insulin concentrations were also similar in the caffeine and placebo trials. After caffeine administration, glucose disposal was 6.38 +/- 0.76 mg/kg body wt compared with 8.42 +/- 0.63 mg/kg body wt after the placebo trial. This represents a significant (P < 0.05) decrease (24%) in glucose disposal after caffeine ingestion. In addition, carbohydrate storage was 35% lower (P < 0.05) in the caffeine trial than in the placebo trial. Furthermore, even when the difference in glucose disposal was normalized between the trials, there was a 23% difference in the amount of carbohydrate stored after caffeine administration compared with placebo administration. Caffeine ingestion also resulted in higher plasma epinephrine levels than placebo ingestion (P < 0.05). These data support our hypothesis that caffeine ingestion decreases glucose disposal and suggests that adenosine plays a role in regulating glucose disposal in resting humans.

The Graduated Embryo Score (GES) predicts blastocyst formation and pregnancy rate from cleavage-stage embryos

BACKGROUND

Embryo morphology and cleavage rates alone do not consistently identify embryos with high implantation potential following IVF. Blastocyst transfer has been reported to improve success rates by identifying potentially superior quality embryos. Algorithms for predicting IVF outcomes based on the presence of early developmental milestones have been proposed. Here we introduce the Graduated Embryo Score (GES).

METHODS

Nucleolar alignment along the pronuclear axis, regular cleavage and degree of fragmentation at the first cell division, and cell number and morphology on day 3 were weighted to create a possible GES of 100 for each of 1245 fertilized embryos derived from 109 patients aged <40 years. The GES was correlated with IVF outcome.

RESULTS

Of 983 embryos for extended culture, 349 (36%) developed to blastocyst and 180 (18%) were good quality (grade I-II). When ranked by cell number and morphology alone, 34% of embryos with > or =7 cells and <20% fragmentation formed good quality blastocysts. Using GES, embryos scoring 90-100 had 64% blastocyst formation compared with 31% scoring 70-85 and with 11% scoring 30-65. Embryos scoring 70-100 had 44% blastocyst development compared with 9% scoring 0-65. Fifty-six patients (51%) conceived on-going gestations from 294 transferred embryos. In patients with at least one transferred embryo scoring > or =70, the pregnancy rate was 59% compared with 34% if all embryos scored <70. The overall implantation rate was 28%. Among embryos scoring 70-100, an implantation rate of 39% was seen, compared with 24% among embryos scoring 0-65.

CONCLUSIONS

Predicting which cleaved embryos will form blastocysts could permit the high success rates associated with blastocyst transfer to be achieved from day 3 embryo transfer.

The role of NO in contact hypersensitivity

Contact dermatitis or contact hypersensitivity (CHS) is a common T lymphocyte-mediated allergic disease characterized by local inflammatory skin reactions following contact with small reactive compounds called haptens. In common with other allergic processes, the development of contact dermatitis proceeds in two phases: a sensitization phase which occurs on first exposure to allergen, and an elicitation phase which occurs on subsequent exposure when the clinical manifestations of the disease are observed. This process is hapten-specific. While the pathophysiology of the sensitization phase is well characterized, our understanding of the elicitation phase is still incomplete, including the relative contribution of the different effector cells and mediators involved. Here we summarize current knowledge of the contribution of nitric oxide (NO) to skin inflammation with special focus on CHS. A number of inflammatory stimuli trigger expression of NO in human and animal skin, and topical application of an NO-releasing cream results in inflammation. Moreover, expression of the inducible isoform of nitric oxide synthase (iNOS) is induced in CHS and iNOS inhibitors injected intradermally suppress CHS responses. However, iNOS-deficient mice develop an aggravated CHS response late in the elicitation phase, suggesting that NO is involved in downregulation of CHS. Based on these data, we propose a comprehensive model of the role of NO in CHS.

Olfactory and behavioral response thresholds to odors of diseased blood differ between hygienic and non-hygienic honey bees (Apis mellifera L.)

Through the use of proboscis-extension reflex conditioning, we demonstrate that honey bees (Apis mellifera L.) bred for hygienic behavior (a behavioral mechanism of disease resistance) are able to discriminate between odors of healthy and diseased brood at a lower stimulus level than bees from a non-hygienic line. Electroantennogram recordings confirmed that hygienic bees exhibit increased olfactory sensitivity to low concentrations of the odor of chalkbrood infected pupae (a fungal disease caused by Ascosphaera apis). Three-week-old hygienic bees were able to discriminate between the brood odors significantly better than three-week old non-hygienic bees. However, the differential performance in brood odor discrimination was primarily genetically based, not a direct result of age, experience, or the temporary behavioral state of the bee. Lower stimulus thresholds for both the olfactory and behavioral responses of hygienic bees may facilitate their ability to detect, uncap and remove diseased brood rapidly from the nest. In contrast, non-hygienic bees, possessing higher response thresholds, may not be able to detect diseased brood as easily. Our results provide an example of how physiological and behavioral differences between the hygienic and non-hygienic honey bee lines, operating at the level of the individual, could produce colony-specific behavioral phenotypes.

Physical activity, total and regional obesity: dose-response considerations

PURPOSE

This review was undertaken to determine whether exercise-induced weight loss was associated with corresponding reductions in total, abdominal, and visceral fat in a dose-response manner.

METHODS

A literature search (MEDLINE, 1966--2000) was performed using appropriate keywords to identify studies that consider the influence of exercise-induced weight loss on total and/or abdominal fat. The reference lists of those studies identified were cross-referenced for additional studies.

RESULTS

Total fat. Review of available evidence suggested that studies evaluating the utility of physical activity as a means of obesity reduction could be subdivided into two categories based on study duration. Short-term studies (< or = 16 wk, N = 20) were characterized by exercise programs that increased energy expenditure by values double (2200 vs 1100 kcal.wk-1) that of long-term studies (> or = 26 wk, N = 11). Accordingly, short-term studies report reductions in body weight (-0.18 vs -0.06 kg x wk(-1)) and total fat (-0.21 vs -0.06 kg x wk(-1)) that are threefold higher than those reported in long-term studies. Moreover, with respect to dose-response issues, the evidence from short-term studies suggest that exercise-induced weight loss is positively related to reductions in total fat in a dose-response manner. No such relationship was observed when the results from long-term studies were examined. Abdominal fat. Limited evidence suggests that exercise-induced weight loss is associated with reductions in abdominal obesity as measured by waist circumference or imaging methods; however, at present there is insufficient evidence to determine a dose-response relationship between physical activity, and abdominal or visceral fat.

CONCLUSION

In response to well-controlled, short-term trials, increasing physical activity expressed as energy expended per week is positively related to reductions in total adiposity in a dose-response manner. Although physical activity is associated with reduction in abdominal and visceral fat, there is insufficient evidence to determine a dose-response relationship.

Beta-oxidation of linoleate in obese men undergoing weight loss

BACKGROUND

In animals, the whole-body content and accumulation of linoleate can be measured and compared with its intake to determine linoleate beta-oxidation. This method can also provide quantitative information about the beta-oxidation of linoleate in humans.

OBJECTIVES

The objectives of the study were to 1) use the wholebody fatty acid balance method to quantify whole-body concentrations of linoleate in humans, 2) estimate the distribution of linoleate between adipose and lean tissue, and 3) assess the effect of weight loss on linoleate stores and beta-oxidation in obese humans.

DESIGN

Nine healthy obese men underwent supervised weight loss for 112 d (16 wk). Magnetic resonance imaging data and fatty acid profiles from fat biopsies were both used to determine linoleate stores in adipose and lean tissue and in the whole body. Linoleate beta-oxidation was calculated as intake - (accumulation + excretion).

RESULTS

Mean weight loss was 13 kg and linoleate intake was 24 +/- 6 mmol/d over the study period. Whole-body loss of linoleate was 37 +/- 18 mmol/d, or 28% of the level before weight loss. Combining the intake and whole-body loss of linoleate resulted in linoleate beta-oxidation exceeding intake by 2.5-fold during the weight-loss period.

CONCLUSIONS

All dietary linoleate is beta-oxidized and at least an equivalent amount of linoleate is lost from the body during moderate weight loss in obese men. The method studied permits the assessment of long-term changes in linoleate homeostasis in obese humans and may be useful in determining the risk of linoleate deficiency in other conditions.

Basis of hematopoietic defects in platelet-derived growth factor (PDGF)-B and PDGF beta-receptor null mice

Platelet-derived growth factor (PDGF)-B and PDGF beta-receptor (PDGFR beta) deficiency in mice is embryonic lethal and results in cardiovascular, renal, placental, and hematologic disorders. The hematologic disorders are described, and a correlation with hepatic hypocellularity is demonstrated. To explore possible causes, the colony-forming activity of fetal liver cells in vitro was assessed, and hematopoietic chimeras were demonstrated by the transplantation of mutant fetal liver cells into lethally irradiated recipients. It was found that mutant colony formation is equivalent to that of wild-type controls. Hematopoietic chimeras reconstituted with PDGF-B(-/-), PDGFR beta(-/-), or wild-type fetal liver cells show complete engraftment (greater than 98%) with donor granulocytes, monocytes, B cells, and T cells and display none of the cardiovascular or hematologic abnormalities seen in mutants. In mouse embryos, PDGF-B is expressed by vascular endothelial cells and megakaryocytes. After birth, expression is seen in macrophages and neurons. This study demonstrates that hematopoietic PDGF-B or PDGFR beta expression is not required for hematopoiesis or integrity of the cardiovascular system. It is argued that metabolic stress arising from mutant defects in the placenta, heart, or blood vessels may lead to impaired liver growth and decreased production of blood cells. The chimera models in this study will serve as valuable tools to test the role of PDGF in inflammatory and immune responses. (Blood. 2001;97:1990-1998)

Detection of dissection and remodeling of atherosclerotic lesions in rabbits after balloon angioplasty by magnetic-resonance imaging

OBJECTIVE

To assess the usefulness of magnetic-resonance imaging (MRI) for monitoring acute changes after angioplasty of preexisting lesions in rabbits with basal lesions similar to those observed in humans.

METHODS

A combination of Fogarty balloon injury (1 week after initiation of diet) and a mildly hypercholesterolemic diet (0.2% cholesterol and 5% peanut oil) was used to promote the rapid formation of atherosclerotic lesions in 16 New Zealand white rabbits. After 5 months of the diet, angioplasty was performed on these lesions with a Grüntzig catheter in both iliac arteries and the abdominal aorta. MRI was used to monitor the initial formation of lesions after 3 and 5 months of the diet, and 2 days, 2 weeks, and 1 and 2 months after angioplasty.

RESULTS

The combination of early Fogarty injury and mildly hypercholesterolemic diet induced fibroproliferative lesions similar to type Vb atherosclerotic lesions seen in humans. Angioplasty induced deep dissections at the shoulders of lesions in the majority of animals. These dissections often extended into the media. The cellular, proliferative response after angioplasty was localized and limited to sites of dissection. A significant increase in area of arterial wall was observed after angioplasty at sites of dissection without any loss of lumen. In contrast, proximal and distal to the sites of injury, there was no change in wall area but a transient reduction in lumen area.

CONCLUSIONS

Comparison of MRI results with histology confirmed that changes in the wall and lumen, including small linear dissections in the lesions and arterial remodeling, are detectable by MRI.

Exercise alone is an effective strategy for reducing obesity and related comorbidities

The commonly held view that exercise alone is not a useful strategy for obesity reduction is drawn from studies with limitations that confound interpretation. Recent evidence counters the dogma that daily exercise produces only modest weight loss and suggests that exercise without diet restriction is an effective strategy for reducing obesity and related co-morbidities.