Flaxseed and lignans increase cecal beta-glucuronidase activity in rats.

Flaxseed has been shown in previous studies to decrease some early markers of colon cancer risk in part because of its lignans. This study determined whether the intake of flaxseed and lignans is related to the activity of bacterial beta-glucuronidase, an enzyme suggested to increase colon cancer risk. Seven groups of six female rats each were fed, for four weeks, a basal high-fat (20%) diet (BD), BD supplemented with 2.5%, 5.0%, or 10.0% flaxseed, or BD with daily gavage of 0.75, 1.5, or 3.0 mg of secoisolariciresinol diglycoside (SDG), the major mammalian lignan precursor. The specific and total activities of beta-glucuronidase in the cecum were significantly related to the levels of flaxseed (r = 0.539, p < 0.008 and r = 0.599, p < 0.002, respectively) and SDG (r = 0.567, p < 0.007 and r = 0.435, p < 0.04, respectively). The urinary mammalian lignan excretion also increased with increasing flaxseed or SDG levels and thus was significantly related to the specific activity (r = 0.38, p < 0.017) and total activity (r = 0.429, p < 0.007) of beta-glucuronidase. Because flaxseed and lignans are colon cancer protective, it is concluded that, in contrast to other studies, beta-glucuronidase activity may play a beneficial role in their presence by increasing mammalian lignan absorption and enterohepatic circulation.     

Dose effects of flaxseed and its lignan on N-methyl-N-nitrosourea-induced mammary tumorigenesis in rats

Dietary supplementation with flaxseed or its lignan secoisolariciresinol diglycoside (SDG) has reduced dimethylbenz[a]anthracene-induced mammary tumor size and number in rats. The objective of this study was to determine whether flaxseed has a dose-dependent effect on N-methyl-N-nitrosourea (MNU)-induced mammary tumor promotion and whether this effect can be attributed to its SDG. Two days after injection with MNU (50 mg/kg body wt i.p.), female Sprague-Dawley rats were fed a high-fat (20% soybean oil) AIN-93G basal diet alone (BD) or supplemented with flaxseed (2.5% F and 5% F) or SDG by gavage [SDG in 2.5% F (LSDG) and SDG in 5% F (HSDG)] for 22 weeks. Although tumors tended to be smallest in the 5% F group throughout the experimental period, flaxseed feeding did not significantly affect tumor size, multiplicity, or incidence in comparison to BD. However, there was a dose-dependent effect of SDG on tumor multiplicity. Tumor multiplicity was lowest in the HSDG group and highest in the LSDG group throughout treatment (p < 0.05), indicating that HSDG inhibited, whereas LSDG promoted, MNU-induced mammary tumor development. Tumor invasiveness and grade were decreased in all treatment groups compared with the BD (p < 0.032). Thus, although flaxseed feeding had no significant effect on tumor growth indexes, flaxseed and SDG treatment, regardless of dose, appeared to delay the progression of MNU-induced mammary tumorigenesis. Disparities between this study and previous studies on flaxseed may be related to differences in experimental design, the use and dose of a different carcinogen, and protective effects by the alpha-linolenic acid present in the BD.     

Electron microscopy and X-ray microanalyses of uterine epithelium from lead-injected mice in an experimental delay of implantation

Mice in experimental delay of implantation were injected intravenously with 75 g · g^–1 body weight of lead chloride, corresponding to a dose of lead of about 56 g · g^–1 body weight. Delay of implantation was obtained by ovariectomy 3 days after mating followed by a depot dose of progesterone every fifth day. Electron microscopy showed that the uterine lumen, which was closed in control mice, was opened in lead-injected mice. This morphology suggested that lead caused an increase in uterine secretion. X-ray microanalysis of pyroantimonate precipitates in the uterine epithelium of injected mice demonstrated lead in the precipitates, suggesting that lead could have a direct effect on the function of the uterine epithelium and that lead also could be secreted into the uterine lumen and affect the blastocysts.     

Assessment of maternal nutrition.

A booklet, "Assessment of Maternal Nutrition," has been published by the American College of Obstetricians and Gynecologists in cooperation with The American Dietetic Association as a useful guide for physicians, nurses, dietitians, and nutritionists. Nutritional risks during pregnancy are clearly outlined. Clinical, dietary, and biochemical factors, as well as medical, obstetric, and social factors, are delineated as components of nutritional assessment. An A.D.A. Liaison Committee had major responsibility for the development of the "Eating Habits Questionnaire," a tool to screen dietary intake for major deficits and excesses, which is included in the booklet. It should be useful also as a starting point for nutrition education. Additional evaluation of the use and reliability of the screening tool is recommended.     

Urinary composition and postprandial blood changes in H-secoisolariciresinol diglycoside (SDG) metabolites in rats do not differ between acute and chronic SDG treatments

Although chronic exposure to secoisolariciresinol diglycoside (SDG) was shown to alter (3)H-SDG metabolite disposition in rats, the proportion of measured radioactivity attributed to known or unknown SDG metabolites was not determined. Using HPLC and GC-MS, two experiments were conducted to determine the effect of acute (1 d) vs. chronic (10 d) SDG treatment on major urinary metabolites of (3)H-SDG in female, Sprague-Dawley rats (70-72-d-old) over a 48-h period and if new urinary metabolites were detectable in rats fed nonradioactive flaxseed or SDG. A third experiment was conducted to determine changes in postprandial blood levels of (3)H-SDG metabolites over a 24-h period with acute or chronic SDG treatment. Regardless of treatment, enterodiol, enterolactone and secoisolariciresinol accounted for 75-80% of urine radioactivity. Four potential new lignan metabolites, two of which were detected in the urine of rats fed nonradioactive flaxseed or SDG, were found. Type of treatment had no effect on levels of individual urinary metabolites of (3)H-SDG. As observed for plasma lignans in women fed flaxseed, blood radioactivity peaked at 9 h and remained high until 24 h in both treatment groups, suggesting that blood lignan kinetics might be similar with flaxseed or SDG consumption and that they were comparable between humans and rats. In conclusion, the main urinary lignan metabolites were enterodiol, enterolactone and secoisolariciresinol. Urinary composition or blood levels of radioactive lignans were not affected by the duration of SDG exposure. Thus, while chronic SDG exposure alters lignan disposition in rats, it does not change the metabolite profile.     

The operative management of screen-detected breast cancers

BACKGROUND: Mammographic screening for breast cancer not only reduces the overall mortality from breast cancer but allows greater opportunities for breast-conserving operations. The predicted degree of breast conservation is not being realized, but is increasing in centres that have published their results. METHODS: The operative management of breast cancers diagnosed by BreastScreen Central and Eastern Sydney Screening and Assessment Service were compared between two time periods: January 1988-December 1992 (group 1) and January 1993-December 1995 (group 2). The rate of breast conservation, and other data were compared between the two periods. An attempt was made with multivariate analysis to identify some of the factors that made mastectomy rather than conservation more likely. RESULTS: There were 723 cancers detected that were suitable for analysis (group 1, n = 273; group 2, n = 450). In group 1 the breast conservation rate was 42.9%; this increased significantly to 60.4% in group 2 (P < 0.001). The data were examined to determine if there was any other factor that had changed over the time periods which might account for the increased rate of breast conservation. The use of pre-operative diagnostic techniques such as fine needle aspirate cytology and core biopsy increased significantly. Multivariate analysis comparing the differences in patient age, diagnostic technique, tumour type, grade, size, location and lymph node status, both independently and compositely did not account for the increase in breast conservation in group 2. CONCLUSION: The increase in breast conservation is due to other factors such as the surgeons' approach and patient attitude. The use of pre-operative, minimally invasive tissue sampling techniques is increasing.     

Quantifying the effects of anesthesia on intracellular oxygen via low-cost portable microscopy using dual-emissive nanoparticles

Intracellular oxygenation is an important parameter for numerous biological studies. While there are a variety of methods available for acquiring in vivo measurements of oxygenation in animal models, most are dependent on indirect oxygen measurements, restraints, or anesthetization. A portable microscope system using a Raspberry Pi computer and Pi Camera was developed for attaching to murine dorsal window chambers. Dual-emissive boron nanoparticles were used as an oxygen-sensing probe while mice were imaged in awake and anesthetized states. The portable microscope system avoids altered in vivo measurements due to anesthesia or restraints while enabling increased continual acquisition durations.     

NEUTRALIZING ANTIBODIES IN HUMAN SERUM AFTER INFLUENZA A : THE LACK OF STRAIN SPECIFICITY IN THE IMMUNOLOGICAL RESPONSE

The increased concentrations of neutralizing antibodies against influenza A virus in human serum which occur after influenza A do not differentiate between antigenically different strains of this virus or swine influenza virus but instead appear to possess equal reactivity against these agents. The decrease in antibody levels which occurs with time is also independent of the strain of virus used to measure it.     

Fluticasone alone or in combination with salmeterol vs triamcinolone in asthma.

OBJECTIVES: To compare the efficacies of medium-dose fluticasone propionate (FP), medium-dose triamcinolone acetonide (TAA), and combined low-dose FP plus salmeterol (SL). DESIGN: Randomized, double-blind, triple-dummy, multicenter, 12-week clinical trial. SETTING: Allergy/respiratory care clinics. PATIENTS: Six hundred eighty patients with asthma previously uncontrolled with low-dose inhaled corticosteroids. INTERVENTIONS: FP, 220 microg bid; TAA, 600 microg bid; or FP, 88 microg plus SL, 42 microg bid. MEASUREMENTS AND RESULTS: Outcome measures included FEV1, peak expiratory flow (PEF), supplemental albuterol use, nighttime awakenings, asthma symptoms, and physician global assessment. Compared with TAA, 600 microg bid, treatment with FP 220, microg bid, significantly increased FEV1, morning and evening PEF, and percent symptom-free days, and significantly reduced rescue albuterol use, number of nighttime awakenings, and overall asthma symptom scores (p < or = 0.035). Improvements with low-dose FP, 88 microg, plus SL, 42 microg bid, were significantly (p < or = 0.004) greater than TAA, 600 microg bid, in all the aforementioned efficacy measures as well as percent of rescue-free days. Combined low-dose FP, 88 microg, plus SL, 42 microg bid, also significantly increased FEV1 and percent of rescue-free days, and significantly reduced albuterol use compared with medium-dose FP, 220 microg bid (p < or = 0.018). At endpoint, both FP, 220 microg bid, and FP, 88 microg, plus SL, 42 microg bid, significantly increased FEV1 by 0.48 L and 0.58 L, respectively, compared with 0.34 L with TAA, 600 microg bid. CONCLUSION: In patients who are symptomatic while taking low-dose inhaled corticosteroids, medium-dose FP (440 microg/d) and combination treatment with low-dose FP (176 microg/d) plus SL (84 microg/d) are both more effective than medium-dose TAA (1200 microg/d) in improving pulmonary function and asthma symptom control.