Evaluation of tamoxifen and metabolites by LC-MS/MS and HPLC methods.

Epidemiological and laboratory evidence suggests that quantification of serum or plasma levels of tamoxifen and its metabolites, 4-hydroxy-N-desmethyl-tamoxifen (endoxifen), Z-4-hydroxytamoxifen (4HT), N-desmethyl-tamoxifen (ND-tam), is a clinically useful tool in the assessment and monitoring of breast cancer status in patients taking adjuvant tamoxifen. A liquid chromatographic mass spectrometric method (LC-MS/MS) was used to measure the blood levels of tamoxifen and its metabolites. This fully automated analytical method is specific, accurate and sensitive. The LC-MS/MS automated technique has now become a widely accepted reference method. This study analysed a randomly selected batch of blood samples from participants enrolled in a breast cancer study to compare results from this reference method in 40 samples with those obtained from a recently developed high-performance liquid chromatography (HPLC) method with fluorescence detection. The mean (SD) concentrations for the LC-MS/MS method (endoxifen 12.6 [7.5] ng/mL, tamoxifen 105 [44] ng/mL, 4-HT 1.9 [1.0] ng/mL, ND-tam 181 [69] ng/mL) and the HPLC method (endoxifen 13.1 [7.8] ng/mL, tamoxifen 108 [55] ng/mL, 4-HT 1.8 [0.8] ng/mL, ND-tam 184 [81] ng/mL) did not show any significant differences. The results confirm that the HPLC method offers an accurate and comparable alternative for the quantification of tamoxifen and tamoxifen metabolites.

Role of dietary polyamines in a phase III clinical trial of difluoromethylornithine (DFMO) and sulindac for prevention of sporadic colorectal adenomas.

BACKGROUND: The polyamine-inhibitory regimen difluoromethylornithine (DFMO)+sulindac has marked efficacy in preventing metachronous colorectal adenomas. Polyamines are synthesised endogenously and obtained from dietary sources. Here we investigate dietary polyamine intake and outcomes in the DFMO+sulindac colorectal adenoma prevention trial. METHODS: Dietary polyamine data were available for 188 of 267 patients completing the study. Total dietary polyamine content was derived by the sum of dietary putrescine, spermine and spermidine values and categorised into two groups: highest (>75-100%) vs the lower three quartiles (0-25, 25-50 and 50-75%). Baseline tissue polyamine concentration and ODC1 genotype were determined. Logistic regression models were used for risk estimation. RESULTS: A significant interaction was detected between dietary polyamine group and treatment with regard to adenoma recurrence (P=0.012). Significant metachronous adenoma risk reduction was observed after DFMO+sulindac treatment in dietary polyamine quartiles 1-3 (risk ratio (RR) 0.19; 95% confidence interval (CI) 0.08-0.42; P<0.0001) but not in quartile 4 (RR 1.51; 95% CI 0.53-4.29; P=0.44). However, a lower number of events in the placebo group within dietary quartile 4 confound the aforementioned risk estimates. CONCLUSION: These preliminary findings reveal complex relationships between diet and therapeutic prevention, and they support further clinical trial-based investigations where the dietary intervention itself is controlled.

Epidemiology of invasive pneumococcal disease and vaccine provision in a tertiary referral center.

Invasive pneumococcal disease (IPD) has an all-cause mortality of 5-35 % in the developed world. Pneumococcal vaccination is recommended for at-risk groups, including those infected with human immunodeficiency virus (HIV) and those over 65 years of age. However, adherence to vaccination guidelines is low. We reviewed all cases of IPD in our tertiary referral hospital from 2006 to 2010. IPD was defined as the isolation of Streptococcus pneumoniae from a normally sterile site with a compatible clinical syndrome. Demographics, risk factors, susceptibilities, pneumococcal serotype, mortality, and vaccination status for each patient were analyzed. There were 127 IPD episodes in 122 patients. The overall case fatality rate was 21.2 %. Seventy-two percent of the patients had two or more risk factors that should have prompted pneumococcal vaccination. However, the overall pneumococcal vaccination provision was only 9 %: 64.6 % of all typed isolates were contained in the pneumococcal polysaccharides vaccine 23 (PPV23), 48.8 % in the 7-valent pneumococcal conjugate vaccine (PCV7), and 60.1 % in PCV13. All isolates were fully sensitive to penicillin and cefotaxime. Recurrent IPD was seen in 11 % of the HIV-infected patients, highlighting a particular at-risk group. IPD has a high mortality rate. There is low vaccine provision in our study, although most IPD patients had risk factors that should have prompted vaccination. HIV-positive people are particularly at risk; vaccinating those with persisting CD4 counts less than 200 cells/mm(3) and the use of "prime-boost" strategies may decrease incidence in the future. Newer models of care such as a dedicated vaccine clinic as described in this study may help increase vaccine provision and uptake.

Chances and limits of an improved method to assess water resistance of cosmetic sunscreen products in vitro on polymethylmethacrylate plates.

While sun protection factor (SPF) and UVA protection are the most important determinants of a cosmetic sunscreen product, water resistance is the third important feature. The Colipa in vivo method is the internationally accepted standard method to assess water resistance. It is time-consuming and expensive. A screening method to quickly predict water resistance properties on low cost therefore is a specific request of product developers. Several in vitro screening methods are published but the predictive power of all these methods is limited. In this paper, we describe an adaptation of the in vitro UVA protection method of Colipa for a water resistance screening. Although the method is quick and most parts are standardized and approved by Colipa, the results were not in advantage of other published screening methods. Taking into account, the scatter of the results, seven of 16 sunscreen products that were developed as water resistant formulations could be unambiguously estimated to be water resistant by the in vivo water resistance screening method on five subjects while nine failed. In 10 of these 16 results, the in vitro SPF-based method was in accordance with in vivo findings, whereas in six cases, the method was not predicting correctly. Based on these results, the authors recommend to use the in vitro screening methods to pre-select from candidates which cannot all be tested in vivo. The pre-selected products can be screened in the Colipa in vivo water resistance method with a reduced number of volunteers (usually 5) to predict water resistance. In case, the water resistance estimated in such an in vivo screening is found at about 65% or higher the study can be deemed successful and completed with further subjects to fulfil the Colipa requirements.

Evaluation of daily environmental cleaning and disinfection practices in veterans affairs acute and long-term care facilities: A mixed methods study.

OBJECTIVES: To describe daily environmental cleaning and disinfection practices and their associations with cleaning rates while exploring contextual factors experienced by healthcare workers involved in the cleaning process. METHODS: A convergent mixed methods approach using quantitative observations (ie, direct observation of environmental service staff performing environmental cleaning using a standardized observation form) and qualitative interviews (ie, semistructured interviews of key healthcare workers) across 3 Veterans Affairs acute and long-term care facilities. RESULTS: Between December 2018 and May 2019 a total of sixty-two room observations (N = 3602 surfaces) were conducted. The average observed surface cleaning rate during daily cleaning in patient rooms was 33.6% for all environmental surfaces and 60.0% for high-touch surfaces (HTS). Higher cleaning rates were observed with bathroom surfaces (Odds Ratio OR = 3.23), HTSs (OR = 1.57), and reusable medical equipment (RME) (OR = 1.40). Lower cleaning rates were observed when cleaning semiprivate rooms (OR = 0.71) and rooms in AC (OR = 0.56). In analysis stratified by patient presence (ie, present, or absent) in the room during cleaning, patient absence was associated with higher cleaning rates for HTSs (OR = 1.71). In addition, the odds that bathroom surfaces being cleaned more frequently than bedroom surfaces decreased (OR = 1.97) as well as the odds that private rooms being cleaned more frequently than semi-private rooms also decreased (OR = 0.26; 0.07-0.93). Between January and June 2019 eighteen qualitative interviews were conducted and found key themes (ie, patient presence and semiprivate rooms) as potential barriers to cleaning; this supports findings from the quantitative analysis. CONCLUSION: Overall observed rates of daily cleaning of environmental surfaces in both acute and long-term care was low. Standardized environmental cleaning practices to address known barriers, specifically cleaning practices when patients are present in rooms and semi-private rooms are needed to achieve improvements in cleaning rates.

Quantitative microbial risk assessment of human norovirus infection in environmental service workers due to healthcare-associated fomites.

BACKGROUND: Healthcare-associated norovirus outbreaks place a large burden on healthcare staff. Environmental service workers (ESWs), however, remain understudied despite high contact with potentially contaminated surfaces. Understanding the magnitude of the risk of norovirus infection in healthcare ESWs can protect workers and improve infection control. AIM: This study simulated the risk of norovirus infection for unprotected ESWs after a single fomite contact, assuming no disinfection or protective equipment, in norovirus-positive patient rooms. In addition, the risk of secondary surface transmission from norovirus-exposed ESWs was simulated. METHODS: A quantitative microbial risk assessment employing two-dimensional Monte Carlo simulation with parameters extracted from the literature was used to estimate norovirus infection from multiple fomite contact scenarios defined by: norovirus source (patient vomit/diarrhoea), location (bathroom/patient room) and target outcome (ESW/secondary illness). FINDINGS: Unprotected ESWs have a maximum estimated risk of norovirus infection of 33% (1:3) for a single fomite contact in a room where a norovirus-positive patient had a diarrhoeal event. Patient vomit events lead to fomite contact risk estimates that are four orders of magnitude lower than those for diarrhoeal events. The estimated risk of secondary illness from touching a common surface is as high as 25% (1:4) after single fomite exposure following a diarrhoeal event. CONCLUSIONS: A single fomite contact may lead to sizable risk of norovirus infection in ESWs if personal protective equipment and disinfection are not used appropriately. ESWs can also transfer virus to secondary surfaces, initiating further infections. Interventions are needed to reduce fomite transfer of norovirus, and protect patients and staff from nosocomial infections.

Modulation of abscisic acid signal transduction and biosynthesis by an Sm-like protein in Arabidopsis.

The phytohormone abscisic acid (ABA) regulates plant growth and development as well as stress tolerance. The Arabidopsis sad1 (supersensitive to ABA and drought) mutation increases plant sensitivity to drought stress and ABA in seed germination, root growth, and the expression of some stress-responsive genes. sad1 plants are also defective in the positive feedback regulation of ABA biosynthesis genes by ABA and are impaired in drought stress induction of ABA biosynthesis. SAD1 encodes a polypeptide similar to multifunctional Sm-like snRNP proteins that are required for mRNA splicing, export, and degradation. These results suggest a critical role for mRNA metabolism in the control of ABA signaling as well as in the regulation of ABA homeostasis.

Validating stage of change measures for physical activity and dietary behaviors for overweight women.

OBJECTIVE: To investigate the construct, concurrent and predictive validity of stage of change measures for physical activity (PA), and intakes of fruit and vegetables (FVs), dietary fiber (FB) and dietary fat (DF) among a sample of overweight women. DESIGN: Subjects were 401 women (mean age=41, s.d.=8.7 years; mean body mass index=32.35, s.d.=4.6) recruited to participate in a 12-month weight loss intervention trial. Concurrent validity tests included (1) self-report of current behavior, (2) decisional balance (for example, pros and cons of behavior change), (3) self-efficacy, (4) the MTI Actigraph accelerometer (for the PA staging measure), and (5) a food-frequency questionnaire (for all dietary staging measures). Predictive validity was assessed through tests of the relationship between the baseline stage of change measures and their corresponding behavior 1-year later. RESULTS: Coefficient alpha-tests of internal consistency exceeded 0.70 on the majority of scales. Concurrent validity tests indicated strong validity evidence for three staging measures and little validity for the DF staging measure (eta(2) range, 0.02-0.18). All staging algorithms demonstrated predictive validity (eta(2) range, 0.04-0.126). CONCLUSION: Staging measures can determine motivational readiness for overweight women, contribute to the standardization of stage of change assessment and facilitate cross-study comparisons.

Insulin Resistance Improves More in Women than In Men in Association with a Weight Loss Intervention.

BACKGROUND: Fasting glucose and homeostatic model assessment-insulin resistance (HOMA-IR) are important measures of the risk for metabolic syndrome and diabetes. Weight loss interventions are considered part of the first line of therapy for those who develop disease states associated with insulin resistance, such as pre-diabetes, diabetes, or metabolic syndrome. Sex differences in insulin resistance have been extensively reported, but sex differences in the ability to improve insulin sensitivity are not well-established. This study sought to identify factors that predict change in HOMA-IR in response to weight loss. METHODS: Non-diabetic subjects who were overweight/obese (n=100) were randomly assigned to a walnut-enriched reduced-energy diet or a standard reduced-energy-density diet in a 6-month weight loss intervention. There were no significant differences in weight change, glucose, insulin, or HOMA-IR between the two diet groups. These subjects were combined into a single cohort and analyzed with multivariate analysis. RESULTS: The combined groups lost an average of 8.7 kg (p<0.0001), decreased serum glucose by an average 0.2 mmol/L (p<0.001), and decreased HOMA-IR by an average of 1.4 (p<0.0001). Change in HOMA-IR (R2=0.69) was positively associated with weight change (p<0.0001) and male sex (p<0.01), and negatively associated with baseline HOMA-IR (p<0.0001). CONCLUSION: Findings from this study suggest that men may have a more difficult time improving insulin sensitivity as compared with women with an equivalent weight loss and baseline HOMA-IR. One hypothesis to explain the differences across sexes may be due to sex differences in visceral adipose fat (VAT). This may mean that insulin resistant men require more aggressive intervention than women to prevent progression to metabolic syndrome or diabetes.

Plant regulators. Insensitivity is in the genes.

The cloning of loci determining abscisic acid insensitivity in Arabidopsis has identified a phosphatase and a transcriptional activator that mediate responses to abscisic acid and so regulate plant growth and development.

Interleukin-1 receptor blockade improves survival and hemodynamic performance in Escherichia coli septic shock, but fails to alter host responses to sublethal endotoxemia.

The present study was undertaken to evaluate the extent to which an endogenous interleukin-1 (IL-1) response contributes to the hemodynamic and metabolic consequences of sublethal endotoxemia or lethal Gram-negative septic shock. Young, healthy baboons received either a sublethal dose of lipopolysaccharide (LPS) or an LD100 of live Escherichia coli bacteria, and one half of the animals in each group were continuously infused with IL-1 receptor antagonist (IL-1ra). Plasma IL-1 beta was not detected in this model of endotoxemia. Administration of IL-1ra had only minimal effects on the modest hemodynamic and metabolic responses to sublethal endotoxemia, and did not attenuate the plasma cytokine response. In contrast, high circulating levels of IL-1 beta (range 300-800 pg/ml) were seen during lethal E. coli septic shock. IL-1ra treatment significantly attenuated the decrease in mean arterial blood pressure (MAP) (from -72 +/- 8 to -43 +/- 6 mm Hg; P less than 0.05) and cardiac output (from -0.81 +/- 0.17 to -0.48 +/- 0.15 liter/min; P less than 0.05), and significantly improved survival from 43 to 100% at 24 h (P less than 0.05). The plasma IL-1 beta and IL-6 responses to lethal E. coli septic shock were also significantly diminished by IL-1ra treatment (P less than 0.05), whereas tumor necrosis factor-alpha (TNF alpha) concentrations were unaffected. We conclude that an exaggerated systemic IL-1 beta response is characteristic of lethal E. coli septic shock, and contributes significantly to the hemodynamic and metabolic consequences of E. coli septic shock. IL-1ra can significantly attenuate the cytokine cascade and improve survival.

Macrophage growth arrest by cyclic AMP defines a distinct checkpoint in the mid-G1 stage of the cell cycle and overrides constitutive c-myc expression.

Proliferation of a murine macrophage cell line (BAC1.2F5) in response to colony-stimulating factor 1 (CSF-1) is inhibited by prostaglandin E2 (PGE2)-mediated elevation of intracellular cyclic AMP (cAMP). When BAC1.2F5 cells were growth arrested in early G1 by CSF-1 starvation and stimulated to synchronously enter the cell cycle by readdition of growth factor, PGE2 inhibited [3H]thymidine incorporation when added before mid-G1, but its addition at later times did not block the onset of S phase. Reversible cell cycle arrest mediated by a cAMP analog required the presence of CSF-1 for cells to initiate DNA synthesis, whereas cells released from an aphidicolin block at the G1/S boundary entered S phase in the absence of CSF-1. PGE2 or cAMP analogs did not block the initial induction of c-myc mRNA by CSF-1 but abolished the CSF-1-dependent expression of c-myc mRNA in the mid-G1 stage of the cell cycle. The cAMP-mediated reduction in c-myc RNA levels was due to decreased c-myc transcription. However, CSF-1-dependent BAC1.2F5 clones infected with a c-myc retrovirus were growth arrested by cAMP analogs despite constitutive c-myc expression. Therefore, the reduction of endogenous c-myc expression by cAMP is neither necessary nor sufficient for growth inhibition.

Phosphatidylcholine hydrolysis and c-myc expression are in collaborating mitogenic pathways activated by colony-stimulating factor 1.

Stimulation of diglyceride production via phospholipase C (PLC) hydrolysis of phosphatidylcholine was an early event in the mitogenic action of colony-stimulating factor 1 (CSF-1) in the murine macrophage cell line BAC1.2F5 and was followed by a second phase of diglyceride production that persisted throughout the G1 phase of the cell cycle. Addition of phosphatidylcholine-specific PLC (PC-PLC) from Bacillus cereus to the medium of quiescent cells raised the intracellular diglyceride concentration and stimulated [3H]thymidine incorporation, although PC-PLC did not support continuous proliferation. PC-PLC treatment did not induce tyrosine phosphorylation or turnover of the CSF-1 receptor. The major protein kinase C (PKC) isotype in BAC1.2F5 cells was PKC-delta. Diglyceride production from PC-PLC did not target PKC-delta, since unlike phorbol esters, PC-PLC treatment neither decreased the electrophoretic mobility of PKC-delta nor increased the amount of GTP bound to Ras, and PC-PLC was mitogenically active in BAC1.2F5 cells in which PKC-delta was downregulated by prolonged treatment with phorbol ester. PC-PLC mimicked CSF-1 action by elevating c-fos and junB mRNAs to 40% of the level induced by CSF-1; however, PC-PLC induced c-myc mRNA to only 5% of the level in CSF-1-stimulated cells. PC-PLC addition to CSF-1-dependent BAC1.2F5 clones that constitutively express c-myc increased [3H]thymidine incorporation to 86% of the level evoked by CSF-1 and supported slow growth in the absence of CSF-1. Therefore, PC-PLC is a component of a signal transduction pathway leading to transcription of c-fos and junB that collaborates with c-myc and is independent of PKC-delta and Ras activation.

Complementation of growth factor receptor-dependent mitogenic signaling by a truncated type I phosphatidylinositol 4-phosphate 5-kinase.

Substitution of phenylalanine for tyrosine at codon 809 (Y809F) of the human colony-stimulating factor 1 (CSF-1) receptor (CSF-1R) impairs ligand-stimulated tyrosine kinase activity, prevents induction of c-MYC and cyclin D1 genes, and blocks CSF-1-dependent progression through the G1 phase of the cell cycle. We devised an unbiased genetic screen to isolate genes that restore the ability of CSF-1 to stimulate growth in cells that express mutant CSF-1R (Y809F). This screen led us to identify a truncated form of the murine type Ibeta phosphatidylinositol 4-phosphate 5-kinase (mPIP5K-Ibeta). This truncated protein lacks residues 1 to 238 of mPIP5K-Ibeta and is catalytically inactive. When we transfected cells expressing CSF-1R (Y809F) with mPIP5K-Ibeta (delta1-238), CSF-1-dependent induction of c-MYC and cyclin D1 was restored and ligand-dependent cell proliferation was sustained. CSF-1 normally triggers the rapid disappearance of CSF-1R (Y809F) from the cell surface; however, transfection of cells with mPIP5K-Ibeta (delta1-238) stabilized CSF-1R (Y809F) expression on the cell surface, resulting in elevated levels of ligand-activated CSF-1R (Y809F). These results suggest a role for PIP5K-Ibeta in receptor endocytosis and that the truncated enzyme compensated for a mitogenically defective CSF-1R by interfering with this process.

Factors Associated with Visceral Fat Loss in Response to a Multifaceted Weight Loss Intervention.

BACKGROUND: Visceral adipose tissue is more metabolically active than other fat depots and is more closely associated with obesity-related diseases, such as cardiovascular disease and type 2 diabetes, than indicators of obesity, such as body mass index. Across various strategies to promote weight loss, including energy-reduced diet and exercise, variable effects on VAT compared to loss of total body fat have been reported. METHODS: To examine the effect of a behavioral weight loss intervention using portion-controlled prepackaged entrées on VAT, we examined data and measurements from overweight/obese men and women (N=183) who were assigned to a weight loss intervention and prescribed a reduced-energy diet with either portion-controlled prepackaged entrées or self-selected meals in a randomized clinical trial. VAT was estimated with dual-energy X-ray absorptiometry at baseline and study end (12 weeks). RESULTS: VAT loss was greater for the prepackaged entrees group (p=0.02), with an average loss of 29% compared to an average loss of 19% among participants consuming self-selected meals. VAT (mean [SEM]) was 1651 (71) g and 1546 (157) g at baseline and 1234 (59) g and 1278 (118) g at study end in the prepackaged entrees and self-selected meal groups, respectively. Greater VAT loss was associated with higher baseline weight and VAT, and greater weight loss, but not associated with age or physical activity. CONCLUSION: Prescribing portion-controlled prepackaged entrees in a behavioral weight loss intervention promotes a reduction in VAT, which should promote improved metabolic profile and reduced cardiovascular disease risk.

Lipid biosynthesis as a target for antibacterial agents.

Fatty acid biosynthesis, the first stage in membrane lipid biogenesis, is catalyzed in most bacteria by a series of small, soluble proteins that are each encoded by a discrete gene (Fig. 1; Table 1). This arrangement is termed the type II fatty acid synthase (FAS) system and contrasts sharply with the type I FAS of eukaryotes which is a dimer of a single large, multifunctional polypeptide. Thus, the bacterial pathway offers several unique sites for selective inhibition by chemotherapeutic agents. The site of action of isoniazid, used in the treatment of tuberculosis for 50 years, and the consumer antimicrobial agent triclosan were revealed recently to be the enoyl-ACP reductase of the type II FAS. The fungal metabolites, cerulenin and thiolactomycin, target the condensing enzymes of the bacterial pathway while the dehydratase/isomerase is inhibited by a synthetic acetylenic substrate analogue. Transfer of fatty acids to the membrane has also been inhibited via interference with the first acyltransferase step, while a new class of drugs targets lipid A synthesis. This review will summarize the data generated on these inhibitors to date, and examine where additional efforts will be required to develop new chemotherapeutics to help combat microbial infections.

The 1.8 A crystal structure and active-site architecture of beta-ketoacyl-acyl carrier protein synthase III (FabH) from escherichia coli.

BACKGROUND: beta-Ketoacyl-acyl carrier protein synthase III (FabH) initiates elongation in type II fatty acid synthase systems found in bacteria and plants. FabH is a ubiquitous component of the type II system and is positioned ideally in the pathway to control the production of fatty acids. The elucidation of the structure of FabH is important for the understanding of its regulation by feedback inhibition and its interaction with drugs. Although the structures of two related condensing enzymes are known, the roles of the active-site residues have not been experimentally tested. RESULTS: The 1.8 A crystal structure of FabH was determined using a 12-site selenium multiwavelength anomalous dispersion experiment. The active site (Cys112, His244 and Asn274) is formed by the convergence of two alpha helices and is accessed via a narrow hydrophobic tunnel. Hydrogen-bonding networks that include two tightly bound water molecules fix the positions of His244 and Asn274, which are critical for the decarboxylation and condensation reactions. Surprisingly, the His244-->Ala mutation does not affect the transacylation reaction suggesting that His244 has only a minor influence on the nucleophilicity of Cys112. CONCLUSIONS: The histidine and asparagine active-site residues are both required for the decarboxylation step in the condensation reaction. The nucleophilicity of the active-site cysteine is enhanced by the alpha-helix dipole effect, and an oxyanion hole promotes the formation of the tetrahedral transition state.

Suppression of human colorectal mucosal prostaglandins: determining the lowest effective aspirin dose.

BACKGROUND: A variety of studies have supported the finding that regular intake of aspirin (acetylsalicylic acid) or nonsteroidal anti-inflammatory agents can affect colorectal cancer carcinogenesis. These agents inhibit the synthesis of prostaglandins. High levels of prostaglandins are observed in colon cancer tissues. PURPOSE: Experiments were planned to determine the lowest dose of aspirin that can markedly suppress the levels of mucosal prostaglandins E2 and F(2alpha) in colorectal mucosa and to determine whether a relationship exists between these levels and plasma levels of both acetylsalicylic acid and its metabolite, salicylic acid. METHODS: Healthy men and women aged 18 years or older participated in the study. The participants took a single, daily dose of aspirin (40.5, 81, 162, 324, or 648 mg) or a placebo for 14 days. Colorectal biopsy specimens were taken at baseline, 24 hours after the first dose of aspirin, and 24-30 hours and 72-78 hours after the last, i.e., fourteenth, daily dose of aspirin. The biopsy specimens were assayed for prostaglandins E2 and F(2alpha) by use of a competitive enzyme immunoassay. Plasma concentrations of acetylsalicylic acid and salicylic acid were determined by use of high-performance liquid chromatography. All P values are two-sided. RESULTS: A total of 65 subjects (10 receiving placebo, groups of 10 each receiving 40.5, 81, 162, or 324 mg of aspirin, and a group of 15 receiving 648 mg of aspirin) completed the protocol. One subject reported unacceptable drug-induced toxic effects and did not complete the protocol; other subjects reported acceptable side effects. The lowest dose to significantly suppress colorectal mucosal prostaglandin E2 concentrations from baseline at 24 hours after the first dose (by 22.6%; P = .002) and at 24-30 hours after the last dose (by 14.2%; P = .021) was 162 mg. At 72-78 hours after the last dose, there was significant suppression for subjects receiving 81 mg (by 23.7%; P = .008). The lowest dose to significantly suppress colorectal mucosal prostaglandin F(2alpha) concentrations from baseline at 24 hours after the first dose (by 18.3%; P = .032) was 324 mg. The lowest dose causing a marked reduction in the level of prostaglandin F(2alpha) at 24-30 hours (by 15.1%; P = .003) and 72-78 hours (by 23.0%; P = .0002) after the last dose was 40.5 mg. No detectable amounts of acetylsalicylic acid or salicylic acid were present in the plasma at any of the biopsy time points. CONCLUSIONS: The lowest doses of aspirin taken daily for 14 days to significantly suppress concentrations of colorectal mucosal prostaglandins E2 and F(2alpha) were 81 and 40.5 mg, respectively. The suppression occurred without detectable amounts of aspirin or salicylic acid in the plasma at the time points studied. On the basis of these observations, we recommend a single, daily dose of 81 mg of aspirin in future studies of this drug as a chemopreventive agent for colorectal cancer.

Ankle Impingement Caused by an Intra-articular Plica: A Report of 2 Cases.

UNLABELLED: Entrapment of soft tissues in the anterolateral gutter of the ankle can cause impingement. When symptomatic, patients complain of chronic ankle pain exacerbated with dorsiflexion. Symptoms of instability and a history of recurring ankle sprains are common findings. Plain radiographs and magnetic resonance imaging may assist clinicians in identifying associated pathology. We present 2 cases of ankle impingement occurring in the setting of equivocal examination and imaging findings. In both cases, arthroscopy revealed a likely congenital, intra-articular plica. LEVELS OF EVIDENCE: Therapeutic, Level IV: Case Study.