Fluoropyrimidine type, patient age, tumour sidedness and mutation status as determinants of benefit in patients with metastatic colorectal cancer treated with EGFR monoclonal antibodies: individual patient data pooled analysis of randomised trials from the ARCAD database.

BACKGROUND: KRAS mutations in metastatic colorectal cancer (mCRC) are used as predictive biomarkers to select therapy with EGFR monoclonal antibodies (mAbs). Other factors may be significant determinants of benefit. METHODS: Individual patient data from randomised trials with a head-to-head comparison between EGFR mAb versus no EGFR mAb (chemotherapy alone or best supportive care) in mCRC, across all lines of therapy, were pooled. Overall survival (OS) and progression-free survival (PFS) were compared between groups. Treatment effects within the predefined KRAS biomarker subsets were estimated by adjusted hazard ratio (HRadj) and 95% confidence interval (CI). EGFR mAb efficacy was measured within the KRAS wild-type subgroup according to BRAF and NRAS mutation status. In both KRAS wild-type and mutant subgroups, additional factors that could impact EGFR mAb efficacy were explored including the type of chemotherapy, line of therapy, age, sex, tumour sidedness and site of metastasis. RESULTS: 5675 patients from 8 studies were included, all with known mCRC KRAS mutation status. OS (HRadj 0.90, 95% CI 0.84-0.98, p = 0.01) and PFS benefit (HRadj 0.73, 95% CI 0.68-0.79, p < 0.001) from EGFR mAbs was observed in the KRAS wild-type group. PFS benefit was seen in patients treated with fluorouracil (HRadj 0.75, 95% CI 0.68-0.82) but not with capecitabine-containing regimens (HRadj 1.04, 95% CI 0.86-1.26) (pinteraction = 0.002). Sidedness also interacted with EGFR mAb efficacy, with survival benefit restricted to left-sided disease (pinteraction = 0.038). PFS benefits differed according to age, with benefits greater in those under 70 (pinteraction = 0.001). The survival benefit was not demonstrated in those patients with mutations found in the KRAS, NRAS or BRAF genes. The presence of liver metastases interacted with EGFR mAb efficacy in patients with KRAS mutant mCRC (pinteraction = 0.004). CONCLUSION: The benefit provided by EGFR mAbs in KRAS WT mCRC is associated with left-sided primary tumour location, younger patient age and absence of NRAS or BRAF mutations. Survival benefit is observed with fluorouracil but not capecitabine. Exploratory results support further research in KRAS mutant mCRC without liver metastases.

Different prognostic values of KRAS exon 2 submutations and BRAF V600E mutation in microsatellite stable (MSS) and unstable (MSI) stage III colon cancer: an ACCENT/IDEA pooled analysis of seven trials.

BACKGROUND: The prognostic value of KRAS and BRAFV600E mutations in stage III colon cancer (CC) remains controversial and has never been clearly analyzed in patients with microsatellite instability-high (MSI-H) tumors due to sample size limitations. Data are also lacking for KRAS submutations and prognosis. PATIENTS AND METHODS: We examined clinicopathological variables and prognosis in patients with surgically resected stage III CC who participated in seven clinical trials from the ACCENT/IDEA databases. Associations between KRAS exon 2 and BRAFV600E mutations and time to recurrence (TTR), overall survival (OS), and survival after recurrence (SAR) were assessed using a Cox model. We also analyzed the prognostic value of KRAS exon 2 submutations. RESULTS: Among 8460 patients, 11.4% had MSI-H status. In the MSI-H group, BRAFV600E, KRAS exon 2 mutants, and double-wild-type statuses were detected in 40.6%, 18.1%, and 41.3%, respectively, whereas and in the microsatellite stable (MSS) group, these were detected in 7.7%, 38.6%, and 53.8%, respectively. In the MSS group, 5-year TTR rates of 61.8%, 66.3%, and 72.9% were observed among patients with BRAFV600E, KRAS exon 2 mutants, and those who were DWT, respectively [adjusted hazard ratio (HR) = 1.58 and 1.31, both P < 0.001]. In the MSI-H group, 5-year TTR rates did not differ significantly among the mutated subgroups. Similar results were found for OS. However, survival after relapse was significantly shorter in the KRAS exon 2- and BRAFV600E-mutated patients in both MSS (adjusted HR = 2.06 and 1.15; both P < 0.05) and MSI-H (adjusted HR = 1.99 and 1.81; both P < 0.05) groups. In the MSS group, KRAS exon 2 mutations were associated with TTR, but only p.G12C, p.G12D, and p.G13D were associated with poor outcomes after disease recurrence. CONCLUSIONS: Testing for both KRAS and BRAFV600E mutations in stage III patients should be considered as they can better define individual patient prognosis, and may also enable patient selection for (neo)adjuvant trials dedicated to specific molecular subtypes with poor prognosis.

Evaluation of the change of outcomes over a 10-year period in patients with stage III colon cancer: pooled analysis of 6501 patients treated with fluorouracil, leucovorin, and oxaliplatin in the ACCENT database.

BACKGROUND: Since 2004, adjuvant 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX or FLOX) have been the standard of care for patients with resected colon cancer. Herein we examine the change of outcomes over a 10-year period in patients with stage III colon cancer who received this regimen. PATIENTS AND METHODS: Individual patient data from the ACCENT database was used to compare the outcomes in older (1998-2003) and newer (2004-2009) treatment eras for patients with stage III colon cancer who received adjuvant FOLFOX or FLOX. The outcomes were compared between the two groups by the multivariate Cox proportional-hazards model adjusting for age, sex, performance score, T stage, N stage, tumor sidedness, and histological grade. RESULTS: A total of 6501 patients with stage III colon cancer who received adjuvant FOLFOX or FLOX in six randomized trials were included in the analysis. Patients enrolled in the new era group experienced statistically significant improvement in time to recurrence [3-year rate, 76.1% versus 73.0%; adjusted hazard ratio (HRadj) = 0.83 (95% CI, 0.74-0.92), P = 0.0008], disease-free survival (DFS) [3-year rate, 74.7% versus 72.3%; HRadj = 0.88 (0.79-0.98), P = 0.024], survival after recurrence (SAR) [median time, 27.0 versus 17.7 months; HRadj = 0.65 (0.57-0.74), P < 0.0001], and overall survival (OS) [5-year rate, 80.9% versus 75.7%; HRadj = 0.78 (0.69-0.88), P < 0.0001]. The improved outcomes remained in patients diagnosed at 45 years of age or older, low-risk patients (T1-3 and N1), left colon, mismatch repair proficient (pMMR), BRAF, and KRAS wild-type tumors. CONCLUSION: Improved outcomes were observed in patients with stage III colon cancer enrolled in clinical trials who received adjuvant FOLFOX/FLOX therapy in 2004 or later compared with patients in the older era. Prolonged SAR calls for revalidation of 3-year DFS as the surrogate endpoint of OS in adjuvant clinical trials and reevaluation of optimal follow-up of OS to confirm the trial findings based on the DFS endpoints. CLINICAL TRIALS NUMBERS: NCT00079274; NCT00096278; NCT00004931; NCT00275210; NCT00265811; NCT00112918.

Prognosis of microsatellite instability and/or mismatch repair deficiency stage III colon cancer patients after disease recurrence following adjuvant treatment: results of an ACCENT pooled analysis of seven studies.

BACKGROUND: Microsatellite instable/deficient mismatch repair (MSI/dMMR) metastatic colorectal cancers have been reported to have a poor prognosis. Frequent co-occurrence of MSI/dMMR and BRAFV600E complicates the association. PATIENTS AND METHODS: Patients with resected stage III colon cancer (CC) from seven adjuvant studies with available data for disease recurrence and MMR and BRAFV600E status were analyzed. The primary end point was survival after recurrence (SAR). Associations of markers with SAR were analyzed using Cox proportional hazards models adjusted for age, gender, performance status, T stage, N stage, primary tumor location, grade, KRAS status, and timing of recurrence. RESULTS: Among 2630 patients with cancer recurrence (1491 men [56.7%], mean age, 58.5 [19-85] years), multivariable analysis revealed that patients with MSI/dMMR tumors had significantly longer SAR than did patients with microsatellite stable/proficient MMR tumors (MSS/pMMR) (adjusted hazard ratio [aHR], 0.82; 95% CI [confidence interval], 0.69-0.98; P = 0.029). This finding remained when looking at patients treated with standard oxaliplatin-based adjuvant chemotherapy regimens only (aHR, 0.76; 95% CI, 0.58-1.00; P = 0.048). Same trends for SAR were observed when analyzing MSI/dMMR versus MSS/pMMR tumor subgroups lacking BRAFV600E (aHR, 0.84; P = 0.10) or those harboring BRAFV600E (aHR, 0.88; P = 0.43), without reaching statistical significance. Furthermore, SAR was significantly shorter in tumors with BRAFV600E versus those lacking this mutation (aHR, 2.06; 95% CI, 1.73-2.46; P < 0.0001), even in the subgroup of MSI/dMMR tumors (aHR, 2.65; 95% CI, 1.67-4.21; P < 0.0001). Other factors associated with a shorter SAR were as follows: older age, male gender, T4/N2, proximal primary tumor location, poorly differentiated adenocarcinoma, and early recurrence. CONCLUSIONS: In stage III CC patients recurring after adjuvant chemotherapy, and before the era of immunotherapy, the MSI/dMMR phenotype was associated with a better SAR compared with MSS/pMMR. BRAFV600E mutation was a poor prognostic factor for both MSI/dMMR and MSS/pMMR patients. TRIAL IDENTIFICATION NUMBERS: NCT00079274, NCT00265811, NCT00004931, NCT00004931, NCT00026273, NCT00096278, NCT00112918.

Lenalidomide plus R-CHOP21 in newly diagnosed diffuse large B-cell lymphoma (DLBCL): long-term follow-up results from a combined analysis from two phase 2 trials.

Lenalidomide-RCHOP (R2-CHOP21) has been shown to be safe and effective in patients with untreated diffuse large B-cell lymphoma (DLBCL). The aim of this analysis is to report long-term outcome and toxicities in newly diagnosed DLBCL patients who received R2-CHOP21 in two independent phase 2 trials, conducted by Mayo Clinic (MC) and Fondazione Italiana Linfomi (FIL). All patients received R-CHOP21 plus lenalidomide. Long-term progression-free survival (PFS), time to progression (TTP), overall survival (OS) and late toxicities and second tumors were analyzed. Hundred and twelve patients (63 MC, 49 FIL) were included. Median age was 69 years, 88% were stage III-IV. At a median follow-up of 5.1 years, 5y-PFS was 63.5%, 5y-TTP 70.1% and 5y-OS 75.4%; according to cell of origin (COO): 5y-PFS 52.8% vs 64.5%, 5y-TTP 61.6% vs 69.6% and 5y-OS 68.6% vs 74.1% in germinal center (GCB) vs non-GCB respectively. Four patients experienced grade 4-5 late toxicities. Grade ≤ 3 toxicities were infections (N = 4), thrombosis (N = 1) and neuropathy (N = 3). Seven seconds tumors were observed. Long-term follow-up demonstrates that R2-CHOP21 efficacy was maintained with high rates of PFS, TTP, and OS. Lenalidomide appears to mitigate the negative prognosis of non-GCB phenotype. Incidence of therapy-related secondary malignancies and late toxicities were low.

The effect of intramuscular injection of dinoprost or gonadotropin-releasing hormone in dairy cows on beef quality.

Intramuscular injections of drugs and vaccines cause tissue damage and subsequent effects on tenderness and consumer acceptability of beef. In the 2007 National Market Cow and Bull Beef Quality Audit, 100% of plants reported fabricating subprimal cuts such as rib eyes and tenderloins from cow and bull carcasses. Dairy beef quality should therefore be a consideration when injections are given to dairy animals. The discussion about injection site reactions and tenderness has focused on vaccines and antimicrobial drugs with little concern for the effects of reproductive hormones. The objective of this study was to quantify antemortem the effects of semimembranosis/semitendinosis muscle injection of dinoprost and GnRH in lactating dairy cows by estimating the weight of tissue damaged and comparing that with a drug known to cause extensive tissue damage, flunixin meglumine. Tissue damage was estimated from previously reported equations for grams of muscle tissue damage based on area under the curve of serum concentrations of the muscle enzyme creatine kinase over time. Dinoprost and flunixin injection both caused a significantly increased estimate of muscle tissue damaged compared with needle only (P = 0.0351 and 0.0355, respectively). Dinoprost and flunixin caused a marginally significant increased muscle tissue damage compared with GnRH (P = 0.1394 and 0.1475, respectively). No statistically significant difference was found between the estimated weight of muscle tissue damaged by flunixin compared with dinoprost (P = 1.0000), or by saline compared with GnRH (P = 0.7736) or needle only (P = 0.4902). The assumption that reproductive hormones are less damaging than vaccines and antimicrobial drugs should be examined more closely, including postmortem evaluation of injection site lesions and effects on tenderness.

Analysis of gene expression identifies differentially expressed genes and pathways associated with lymphatic dissemination in patients with adenocarcinoma of the esophagus.

INTRODUCTION: The presence of lymphatic dissemination is an important predictor of survival in esophageal adenocarcinoma (EA). The aim of this study was to discover a prognostic gene expression profile for lymphatic dissemination in EA and to identify genes and pathways that provide oncological insight in lymphatic dissemination. METHODS: Patients who had lymphatic dissemination (N = 55) were compared with patients without lymphatic dissemination (N = 22). Whole-genome oligonucleotide microarrays were used to evaluate the genetic signature of 77 esophageal cancers. Multiple random validation was used to analyze the stability of the molecular signature and predictive power. Gene set enrichment analysis (GSEA) was applied to elucidate oncogenetic pathways. RESULTS: Lymphatic dissemination was correctly predicted in 75 +/- 14% of lymph node positive patients. The absence of lymphatic dissemination was correctly predicted in 41 +/- 23% of lymph-node-negative patients. Argininosuccinate synthetase (ASS) was selected for validation on the protein level because it was present in most prognostic signatures as well as the list of differentially expressed genes. ASS expression was lower (P = 0.048) in patients with lymphatic dissemination than in patients without. GSEA identified that arginine metabolism pathways and lipid metabolism pathways are related to less chance of developing lymphatic dissemination. DISCUSSION: The predictive profile does not outperform current clinical practice to predict the presence of lymphatic dissemination in patients with EA. Several genes, including ASS, and genetic pathways which are important in the development of lymphatic dissemination in EA, were identified.

New tobacco products: do smokers like them?

BACKGROUND: There is little information about smokers who tried potentially reduced exposure products (PREPs) (Eclipse, Omni, Advance Lights, Accord, or Ariva), why they tried them, if they liked these products, and if they will continue to use them. OBJECTIVES: The objectives of this qualitative study were to understand: (1) how smokers who tried PREPs learned about them, (2) reasons for first trying PREPs, (3) which PREP(s) they tried, (4) what they thought of the product at first trial, (5) reasons for continuing or discontinuing use, and (6) whether they would recommend PREPs to others. DESIGN: In October 2002, 16 focus group sessions were conducted with current cigarette smokers aged 30-50 years: eight groups in Chattanooga, Tennessee, and eight in Dallas, Texas. Specific focus groups were composed of white men, white women, African American men, African American women, Hispanic men, or Hispanic women. RESULTS: The majority of the participants learned about PREPs through advertising or promotion, family, friends, and co-workers; major reasons given for first trying PREPs were that the products were free or inexpensive, they wanted to stop smoking, they believed the product claims of fewer health risks, or they were curious; most of them tried Eclipse probably because the focus groups were conducted in the same cities where Eclipse was introduced; most participants did not like PREPs; most discontinued the use of PREPS, some who continued to use them did so infrequently and also kept smoking their regular brands of cigarettes; and most would not recommend PREPs, although a few might recommend them to specific groups (for example, new smokers, the young, women, curious or health conscious people). CONCLUSIONS: Although most established smokers did not like the PREPs they tried and will not recommend them to anyone, a minority of established smokers believe that there may be a market for these products.

Comprehensive tobacco control policies and the smoking behaviour of Canadian adults.

OBJECTIVE: To examine the associations of cigarette prices, restrictions on public smoking, and health education with the odds of adult smoking and amount smoked daily. DESIGN: Multi-level analysis of adult (age 25+) smoking patterns in Canada's National Population Health Survey, after adding administrative data on prices, bylaws, and health education according to the survey respondent's place of residence. SETTING/SUBJECTS: Population based sample of Canadians age 25+ in households (n = 14 355). OUTCOME MEASURES: Smoking status, amount consumed daily. ANALYSIS: Logistic regression for smoking status, multiple regression for amount smoked, with controls for age, education, marital status; separate analyses for men and women. RESULTS: Cigarette prices were positively associated with the odds of being a non-smoker and negatively with amount smoked, for adults of both sexes. Per capita health education expenditures were positively associated with the odds of being a non-smoker and negatively with amount smoked--for men but not women. The restrictiveness of municipal bylaws limiting public smoking was positively associated with the odds of being a non-smoker and negatively with amount smoked--for women but not men. These results are independent of age, education, and marital status. CONCLUSIONS: To be effective, tobacco control must comprise a mix of strategies as men and women respond differently to health education and restrictions on public smoking; taxation, reflected in higher cigarette prices, is the only one of these measures related to smoking for both sexes. This model permits calculations of the level of increase in each measure that is required to reduce the prevalence of smoking by a specified amount.

Is nicotine dependence related to smokers' support for restrictions on smoking?

OBJECTIVES: To examine the relationship between nicotine dependence and attitudes, predicted behaviours and support regarding restrictions on smoking. DESIGN: Population-based, computer-assisted, telephone survey of adults in Ontario, Canada using a two-stage stratified sampling design; 1764 interviews were completed (65% response rate) yielding 424 (24%) cigarette smokers, of whom 354 (83%) smoked daily. The Heaviness of Smoking Index was used as a measure of nicotine dependence. MAIN OUTCOME MEASURE: Attitudes toward smoking restrictions, predicted compliance with more restrictions, and support for total smoking bans. RESULTS: Attitudes favorable to smoking restrictions tended to decrease with increased nicotine dependence, but the associations were not statistically significant after adjusting for demographic variables. Predicted compliance with more restrictions on smoking decreased with higher levels of dependence, as did support for a total ban on smoking in restaurants, workplaces, bingo halls, and hockey arenas. Support for smoking bans in food courts, family fast food restaurants, and bars and taverns did not vary significantly with level of nicotine dependence. CONCLUSIONS: Level of nicotine dependence is associated with intended behaviors and support for smoking restrictions in some settings. These results have implications for tobacco control programs and policies.

Smoking among lesbians, gays, and bisexuals: a review of the literature.

OBJECTIVES: To collect estimates of smoking prevalence among lesbian, gay, and bisexual people from the published literature and to compare with general population estimates. METHODS: Databases were searched for all studies published in English on tobacco use among lesbians, gays, and bisexuals. From 1987 through 2000, twelve studies were identified (four youth, eight adult): seven were based on convenience samples; one on a population-based probability sample; one involved random sampling within selected census tracts; one was based on a large multicenter clinical trial; and two were representative school-based samples. Study findings were compared to national survey data from the corresponding time period. RESULTS: Estimated smoking rates for lesbians, gays, and bisexuals ranged from 38% to 59% among youth and from 11% to 50% among adults. National smoking rates during comparable periods ranged from 28% to 35% for adolescents and were approximately 28% for adults. CONCLUSIONS: While information in the published literature is limited, it appears that smoking rates are higher among adolescent and adult lesbians, gays, and bisexuals than in the general population. Steps should be taken to ensure representation of lesbians, gays, and bisexuals in tobacco-use surveillance and to collect data in order to understand the apparent high smoking rates in these groups. Attempts should be made to target prevention and cessation interventions to lesbians, gays, and bisexuals.

The immune response modifier resiquimod mimics CD40-induced B cell activation.

Members of the imidazoquinoline molecule family, including imiquimod and resiquimod (R-848), have potent antiviral and antitumor activities. Imiquimod cream (5%) (Aldara) is currently indicated for treatment of external genital and perianal warts. Previous characterization of these compounds has focused upon their ability to activate monocytes and dendritic cells, but recent studies have shown that resiquimod also stimulates B lymphocytes to proliferate and express an activated phenotype. This suggests that resiquimod could potentially serve as an effective vaccine adjuvant in stimulating a humoral immune response. This study shows that resiquimod mimics effects of the T-dependent CD40 signal in both mouse and human B cell lines. Resiquimod, like CD40, stimulates antibody secretion, cytokine production, protection from apoptosis, and CD80 upregulation. In addition, it shows synergy with signals delivered by the B cell antigen receptor and heightens CD40-mediated B cell activation, demonstrating that resiquimod can enhance antigen-specific responses in B lymphocytes.

Non-primary care physicians and smoking cessation counseling: Women Physicians' Health Study.

OBJECTIVES: The Women Physicians' Health Study (WPHS) offers a unique opportunity to examine the counseling and screening practices of women physicians in various specialties. In this study we describe the prevalence of self-reported counseling on smoking cessation among non-primary care women physicians and examine the association between their demographic, professional, and personal characteristics and such counseling on smoking cessation. METHODS: Conducted in 1993-1994, WPHS is a nationally representative cross-sectional mailed survey of U.S. women physicians with 4,501 respondents representing all major specialties. Physicians in 9 specialty areas were grouped in 6 categories: (1) anesthesiology; (2) general surgery and surgical subspecialties; (3) emergency medicine; (4) medical subspecialties; (5) psychiatry; and (6) other. Frequent counseling was defined as having counseled patients who were known smokers at every visit or at least once a year. RESULTS: Overall, 45% of the physicians frequently counseled smokers to quit. Medical subspecialists (80%) were most likely and psychiatrists (29%) least likely to counsel frequently. Specialty, perceived relevance of counseling to the physician's practice, and self-confidence in counseling about smoking cessation were associated with frequent counseling. CONCLUSION: Cessation counseling by non-primary care physicians can reduce tobacco-related morbidity and mortality. Increasing perceived relevance and self-confidence among this group of physicians, combined with implementation of system changes and the creation of physician accountability can facilitate the provision of such counseling.

Heterogeneity among smokers and non-smokers in attitudes and behaviour regarding smoking and smoking restrictions.

OBJECTIVE: To determine if smokers and non-smokers cluster into meaningful, discrete subgroups with distinguishable attitudes and behaviours regarding smoking and smoking restrictions. DESIGN: Qualitative research with 45 smokers guided development of questionnaire items applied in a population based telephone survey of 432 current smokers and 1332 non-smokers in Ontario, Canada. METHODS: Cluster analysis of questionnaire items used to categorise adult smokers and non-smokers; comparison of clusters on sociodemographic characteristics and composite knowledge and attitude scores. RESULTS: Smokers clustered in three groups. "Reluctant" smokers (16%) show more concern about other people discovering that they smoke, but parallel "easygoing" smokers (42%) in supporting restrictions on smoking and not smoking around others. "Adamant" smokers (42%) feel restrictions have gone too far, and are less likely to accommodate non-smokers. Significant gradients across categories in the expected direction were observed with respect to smoking status, stage of change, knowledge, and attitude scores, and predicted compliance with restrictions, validating the proposed typology. Non-smokers also clustered into three groups, of which the "adamant" non-smokers (45%) are the least favourably disposed to smoking. "Unempowered" non-smokers (34%) also oppose smoking, but tend not to act on it. "Laissez-faire" non-smokers (21%) are less opposed to smoking in both attitude and behaviour. A significant gradient across categories in the expected direction was observed with respect to composite scores regarding knowledge of the health effects of active and passive smoking and a composite score on support for restrictions on smoking in public places. CONCLUSION: Recognition and consideration of the types of smokers and non-smokers in the population and their distinguishing characteristics could inform the development of tobacco control policies and programmes and suggest strategies to assist implementation.

Knowledge about tobacco and attitudes toward tobacco control: how different are smokers and nonsmokers?

Using data from a 1996 random-digit-dialing computer-assisted telephone survey of Ontario adults, 424 smokers and 1,340 nonsmokers were compared regarding knowledge about the health effects of tobacco use, attitudes toward restrictions on smoking and other tobacco control measures, and predictions of compliance with more restrictions. The response rate was 65%. Smokers were less knowledgeable than nonsmokers. Smokers were also less likely to support bans on smoking in specific locations, but majorities of both groups supported some restriction in most settings. Smokers were more likely than nonsmokers to predict that most smokers would comply with more restrictions, and more than three quarters indicated that they, themselves, would comply. Sizable proportions of both groups, especially smokers, failed to appreciate the effectiveness of taxation in reducing smoking. Support for other control measures also differed by smoking status. Both knowledge and smoking status were independently associated with support for more restrictions and other tobacco control policy measures.

Bisphosphonates directly regulate cell proliferation, differentiation, and gene expression in human osteoblasts.

Bisphosphonates are widely used clinically to treat bone diseases in which bone resorption is in excess. However, the mechanism of bisphosphonate action on bone is not fully understood. Studies of direct action of bisphosphonates on bone have been limited mainly to their effects on bone-resorbing osteoclast cells, with implications that some activity may be mediated indirectly through paracrine factors produced by the bone-forming osteoblast cells. Little is known about the direct effects of bisphosphonates on osteoblasts. In this report, the direct actions of several bisphosphonates on cell proliferation, gene expression, and bone formation by cultured human fetal osteoblasts were examined. Osteoblast cell proliferation was decreased, and cytodifferentiation was increased in a dose-dependent manner in cultures treated with the bisphosphonate pamidronate. In addition, pamidronate treatment increased total cellular protein, alkaline phosphatase activity, and type I collagen secretion in osteoblasts. Consistent with the above-mentioned findings, the rate of bone formation was also increased in osteoblasts cultured with pamidronate. The actions of two other bisphosphonates, the weak-acting etidronate and the potent new analogue zoledronate, were also compared with the action of pamidronate on proliferation of immortalized human fetal osteoblast (hFOB) cells and rate of bone formation. Pamidronate and zoledronate decreased hFOB cell proliferation with equal potency, whereas etidronate decreased proliferation only at much higher concentrations. Studies comparing EDTA and etidronate indicate that etidronate may act indirectly on the hFOB cells by reducing free divalent ion concentrations, whereas pamidronate and zoledronate appear to act on the hFOB cells by a direct action. Both pamidronate and zoledronate increase hFOB cell bone formation, whereas no increase is observed with etidronate and EDTA. Taken together, these observations strongly suggest that treatment with pamidronate or zoledronate enhances the differentiation and bone-forming activities of osteoblasts.

Is smoking associated with the risk of developing Alzheimer's disease? Results from three Canadian data sets.

PURPOSE: To determine whether smoking is associated with Alzheimer's disease (AD). METHODS: Analyses were conducted using three Canadian data sets: the University of Western Ontario Dementia Study (200 cases, 163 controls), the Canadian Study of Health and Aging (258 cases, 258 controls), and the patient database from the Clinic for Alzheimer Disease and Related Disorders at the Vancouver Hospital and Health Sciences Centre (566 cases, 277 controls). The association between smoking and AD was investigated using bivariate analyses and multiple logistic regression models adjusted for the potential confounders age, sex, educational level, family history of dementia, head injury, and hypertension. RESULTS: The results of bivariate analyses were inconsistent across the three data sets, with smoking status a significant protective factor, a significant risk factor, or not associated with AD. The results of multiple logistic regression models, however, were consistent: any association between smoking status and AD disappeared in all three data sets after adjustment for confounders. CONCLUSIONS: Smoking status was consistently not associated with AD across all three data sets after adjustment for confounders. Failure to adjust for relevant confounders may explain inconsistent reports of the influence of smoking on AD. Any protective effect of smoking may be limited to specific AD subtypes (e.g., early onset AD).

Adjuvant activities of immune response modifier R-848: comparison with CpG ODN.

R-848 and imiquimod belong to a class of immune response modifiers that are potent inducers of cytokines, including IFN-alpha, TNF-alpha, IL-12, and IFN-gamma. Many of these cytokines can affect the acquired immune response. This study examines the effects of R-848 on aspects of acquired immunity, including immunoglobulin secretion, in vivo cytokine production, and Ag-specific T cell cytokine production. Results are compared with those of Th1 CpG ODN. R-848 and CpG ODN are effective at skewing immunity in the presence of Alum toward a Th1 Ab response (IgG2a) and away from a Th2 Ab response (IgE). R-848 and CpG ODN are also capable of initiating an immune response in the absence of additional adjuvant by specifically enhancing IgG2a levels. Both R-848 and imiquimod showed activity when given subcutaneously or orally, indicating that the compound mechanism was not through generation of a depot effect. Although CpG ODN behaves similarly to R-848, CpG ODN has a distinct cytokine profile, is more effective than R-848 when given with Alum in the priming dose, and is active only when given by the same route as the Ag. The mechanism of R-848's adjuvant activity is linked to cytokine production, where increases in IgG2a levels are associated with IFN-alpha, TNF-alpha, IL-12, and IFN-gamma induction, and decreases in IgE levels are associated with IFN-alpha and TNF-alpha. Imiquimod also enhances IgG2a production when given with Ag. The above results suggest that the imidazoquinolines R-848 and imiquimod may be attractive compounds for use as vaccine adjuvants and in inhibiting pathological responses mediated by Th2 cytokines.

Influence of a rural primary care clerkship on medical students' intentions to practice in a rural community.

The purpose of this study is to examine the relationship of a rural clerkship to medical students' interest in establishing careers in rural communities. The Association of American Medical Colleges Medical School Graduation Questionnaire (GQ) for years 1988 through 1997 was examined to compare the career plans of students graduating from Morehouse School of Medicine (MSM) with those of all students graduating from United States medical schools before the period 1988 through 1992 and after the period 1993 through 1997, after the inception of the rural clerkship at MSM. Select GQ data items examined include student demographics, medical school experiences, and career plans. Statistical analyses were used to compare pre- and post-clerkship responses for MSM students and to compare their responses with the national trends. Results indicate that, following a transition period, MSM students showed an increased preference for a future career in a rural community. A smaller upward trend in the national data was observed. There appears to be an association between the rural clerkship experience at MSM and the stated preferred career choices of the students.

Models of the relationship of stress, depression, and other psychosocial factors to smoking behavior: a comparison of a cohort of students in grades 6 and 8.

BACKGROUND: Six specific hypotheses regarding putative mechanisms by which stressful life events might lead to initiation of smoking among adolescents were proposed and tested on a Grade 6 cohort of students in Scarborough, Ontario, Canada. In addition, the data were used to determine the set of risk factors for initiation of smoking most pertinent to the experience of the cohort. METHODS: The same relationships were examined for the 1,543 students when they were in Grade 8 and compared to the earlier Grade 6 results. The hypotheses include the effects of personal resources (coping, self-esteem, social support, and mastery), social conformity, rebelliousness, attitudes, smoking environment factors, and gender differences. RESULTS: The hypotheses were not unequivocally supported, except for the hypotheses about attitudes and smoking environment as well as gender effects. Males and females differ with regard to the variables and interrelationships in both years and in the final models developed. In Grade 6, there are more smoking environment items for males than for females. By Grade 8, male smoking is influenced by mastery, social conformity, and rebelliousness, while for females environmental smoking and rebelliousness are important. CONCLUSION: Male and female students differ in how stress, depression, and smoking are related in the presence of psychosocial factors.