Local Therapy in BRCA1/2 Carriers with Operable Breast Cancer: Comparison of Breast Conservation and Mastectomy

Background: Women with inherited germline BRCA1/2 mutations have a 55-85% cumulative risk of breast cancer (BC) by age 70. Thus, knowledge of expected outcomes following various treatments is needed to advise these patients should they be diagnosed with BC. It is unclear whether breast conservation (BCT) offers similar rates of tumor control as mastectomy (M) in BRCA1/2 carriers and it is doubtful whether a randomized trial comparing these options could be performed. Thus, this analysis compares the outcomes between similarly staged women with BRCA1/2 mutations treated with BCT vs. M.Methods: Women with deleterious BRCA1/2 mutations diagnosed with operable BC and who consented to longitudinal studies were identified at 10 institutions in the US, Australia, Spain and Israel. Patient, clinical and treatment characteristics were compared between those receiving BCT and those receiving M +/- RT. Time-to-event endpoints included first failure of treatment, diagnosis of contralateral breast cancer (CBC), and overall and BC-specific survival. Cox regression models were constructed to detect significant associations between patient and clinical characteristics and time-to-event endpoints.Results: Clinical characteristics and outcomes for 302 BCT and 353 M patients were compared. With a median F/U of 8.2 years for BCT patients and 8.9 years following M, 15-year local failure as first failure was significantly higher with BCT vs. M (23.5% vs. 5.5%, p<0.0001). Multivariate analysis indicted choice of local therapy as the only factor significantly predicting local recurrence, with a 4.5-fold risk of local failure with BCT compared to M (p<0.0001). Local failure analyses by cohort revealed the presence of a BRCA2 mutation (HR 2.8; p=0.024) and no use of adjuvant chemotherapy (HR 5.4; p=0.0001) as significant predictors within the BCT group; presence of invasive lobular cancer (HR 9.9; p=0.004) was the only significant predictor within the M cohort. No significant differences were seen in distant failure, BC-specific or overall survival by local therapy. 15-year estimates of CBC were 52.1% with BCT; 41.4% with M; and 37.9% with M+RT (p=0.44). Analyses of BCT vs. M +/- RT and surgery +/- RT did not reveal significant differences in CBC by cohort.Conclusions: The higher risk of local failure in BRCA1/2-associated BC treated with BCT compared to M did not translate into an increased risk of distant failure or mortality. RT did not result in a detectable increase in CBC at 15 years above baseline elevated rates. These results at both the involved and contralateral breasts should be discussed when patients with BRCA1/2-associated BC are considering local treatment options.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 959.

Contralateral risk-reducing mastectomy in BRCA1/2 mutation carriers and other high-risk women in the Kathleen Cuningham Foundation Consortium for Research into Familial Breast Cancer (kConFab)

1509

Background: Contralateral risk-reducing mastectomy (CRRM) reduces contralateral breast cancer (BC) risk by up to 97%. Few studies have examined the prevalence and predictors of CRRM in BC patients at high familial risk of a second primary BC. Methods: Participants were women with unilateral BC and a strong family history of the disease, including BRCA1 and BRCA2 mutation carriers. Data were collected by interview, self-administered questionnaire, and review of pathology and surgical reports. Associations between having CRRM and potential predictors were assessed using multivariate logistic regression. Results: Of 1018 study participants (median follow-up 5.5 years), 154 (15%) underwent CRRM. The median time from initial BC to CRRM was 1 year. More likely to undergo CRRM were women who were younger at the time of their BC diagnosis (odds ratio [OR] = 0.94 per year of age, p < 0.001), those diagnosed more recently (OR = 1.16 per calendar year, p < 0.001), those who underwent mastectomy rather than breast conservation as their initial definitive BC treatment (OR = 5.2, p < 0.001) and those who underwent risk-reducing salpingo-oophorectomy (OR = 3.4, p < 0.001). BRCA1/2 mutation status and tumor characteristics were not independently associated with CRRM uptake. A contralateral BC event occurred in 177 (20.5%) of the 864 women who did not have CRRM, compared with one chest wall event (0.6%) in the 154 women post-CRRM. Conclusions: Younger women with more recently diagnosed BC treated with mastectomy were most likely to elect CRRM. BRCA1/2 mutation status and the competing risk of BC recurrence and death did not appear to influence decision making.

No significant financial relationships to disclose.

Prognosis in BRCA1, BRCA2 associated breast cancer (BC): a prospective Breast Cancer Family Registry (BCFR) international population-based cohort study

Abstract #2072

Hereditary BC occurs at a younger age and is associated with more adverse tumor-related features than sporadic breast cancer (BC) (defined here as BC in those with no 1st or 2nd degree family history of breast or ovarian cancer). Using pre-specified criteria, we assembled a population-based cohort of newly diagnosed BC at 3 centers: Ontario, Canada (1996-98), San Francisco Bay area, USA (1995-2000), Melbourne/Sydney, Australia (1991-1998). Medical information was obtained from medical records; women were followed prospectively for recurrence, new cancers and death. Pathology data were obtained from central review or pathology reports. BRCA1 and BRCA2 mutation testing was performed on 77% and 70% of cases, respectively (sporadic BC cases were not tested at 2 centers). Hereditary and sporadic BC cases were compared using Cox proportional hazards (stratified by center). 3215 eligible cases were enrolled in the BCFR, with a mean age at diagnosis of 46.9 years. Median follow-up was 7.61 years; 565 women had distant recurrences and 547 died. There were 92 cases with BRCA1 and 72 with BRCA2 mutations; 1549 (48.2%) had sporadic BC; the remainder had familial BC as defined above. BRCA1 mutations were associated with young age, estrogen and progesterone receptor (ER and PgR) negativity and high grade; BRCA2 mutations were associated with node positivity and high grade. Distant disease-free survival (DDFS) and overall survival (OS) did not differ significantly between BRCA1 carriers and sporadic cases in univariate or multivariate analyses. DDFS and OS were worse in BRCA2 carriers than in sporadic cases (HR 1.6, p=0.04 and HR 1.8, p=0.01, respectively) in univariate analyses but not in multivariate analyses (DDFS HR 1.0, p=0.98; OS HR 1.13, p=0.61). The small group of BRCA2 carriers who did not receive adjuvant chemotherapy had a significantly worse OS (multivariate HR 3.63, p = 0.005). Furthermore, BRCA2 carriers who received adjuvant tamoxifen had significantly worse OS than women with sporadic BC (HR=2.0, p=0.03). We conclude that BRCA1 and BRCA2 mutations do not independently impact DDFS or OS. Significantly worse outcomes were seen in BRCA2 carrier subgroups defined by adjuvant treatment; this requires further investigation and may have implications for clinical practice.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2072.

Laparoscopic entry techniques

BACKGROUND

Laparoscopy is a very common procedure in gynaecology. Complications associated with laparoscopy are often related to entry. The life-threatening complications include injury to the bowel, bladder, major abdominal vessels, and anterior abdominal-wall vessel. Other less serious complications can also occur, such as post-operative infection, subcutaneous emphysema and extraperitoneal insufflation. There is no clear consensus as to the optimal method of entry into the peritoneal cavity.

OBJECTIVES

The objective of this study was to compare the different laparoscopic entry techniques in terms of their influence on intra-operative and post-operative complications.

SEARCH STRATEGY

This review has drawn on the search strategy developed by the Menstrual Disorders and Subfertility Group. In addition MEDLINE and EMBASE were searched through to July, 2007.

SELECTION CRITERIA

Randomised controlled trials were included when one laparoscopic primary-port-entry technique was compared with another.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by the first two authors. Differences of opinion were registered and resolved by the fourth author. Results for each study were expressed as odds ratio (Peto version) with their 95% confidence intervals.

MAIN RESULTS

The 17 included randomised controlled trials concerned 3,040 individuals undergoing laparoscopy. Overall there was no evidence of advantage using any single technique in terms of preventing major complications. However, there were two advantages with direct-trocar entry when compared with Veress-Needle entry, in terms of avoiding extraperitoneal insufflation (OR 0.06, 95%CI 0.02, 0.23) and failed entry (OR 0.22, 95%CI 0.08, 0.56). There was also an advantage with radially expanding access system (STEP) trocar entry when compared with standard trocar entry, in terms of trocar site bleeding (OR 0.06, 95%CI 0.01, 0.46). Finally, there was an advantage of not lifting the abdominal wall before Veress-Needle insertion when compared to lifting in terms of failed entry without an increase in the complication rate (OR 5.17, 95%CI 2.24, 11.90). However, studies were limited to small numbers, excluding many patients with previous abdominal surgery and women with a raised body mass index, who often had unusually high complication rates.

AUTHORS' CONCLUSIONS

On the basis of evidence investigated in this review, there appears to be no evidence of benefit in terms of safety of one technique over another. However, the included studies are small and cannot be used to confirm safety of any particular technique.

Measuring burden of disease in two inner London boroughs using Disability Adjusted Life Years

BACKGROUND

This paper uses the Disability Adjusted Life Year (DALY) to estimate disease burden at a local level and relates this to programme budget (PB) data.

METHODS

We estimated DALY using the global burden of disease (GBD) template. For years of life lost, local mortality data were used and for years of life with disability, the GBD estimates from World Health Organization EURO A region (including the UK) were used. We used PB data to analyse how healthcare expenditure matched disease burden.

RESULTS

In 2005 the burden of disease in Lambeth was estimated at 36,368 DALYs (13,515 DALYs lost per 100,000) and in Southwark was 34,196 DALYs (13,244 DALYs lost per 100,000). There were gender and area differences. The ranking is different when mortality and morbidity are combined compared with mortality alone. We estimated that the average spend per DALY lost in 2005 was 11,066 pounds in Lambeth and 9390 pounds in Southwark.

CONCLUSIONS

We used a pragmatic approach to estimate overall disease burden providing a local, more comprehensive picture with important differences in spend by disease and health authority area. However, a more detailed approach to support decisions about prioritization based on modelling interventions that impact on avoidable burden of disease is recommended.

Disseminated cutaneous Mycobacterium chelonae infection with multidrug resistance in a patient with panuveitis

We report the case of a 43-year-old immunosuppressed woman who presented with cellulitis of the lower limbs and multiple widespread subcutaneous nodules in a sporotrichoid distribution. Microbiological findings from skin biopsy confirmed Mycobacterium chelonae infection.

Predicting breast cancer risk in BRCA1 and BRCA2 carriers: Methylation studies using intraductal fluid

10537

Background: Genomic alterations are likely to precede the phenotypic changes of breast cancer (BC) and include hyper- methylation of tumour suppressor genes. An intraductal approach, such as ductal lavage (DL), is an attractive means of accessing ductal epithelial and other cells in a prospective fashion. Methods: Women with at least one breast unaffected by BC, with a germline BRCA1 or BRCA2 mutation, attended for 6-monthly DL collection for up to 3 years. Standard methods were used for DNA extraction and bisulfite conversion. Hyper-methylation of p16, RASSF1A, twist and RARβ genes was investigated using a qualitative, real-time, nested PCR assay. Associations between methylation status and categorical variables were tested using Fisher's exact test including cytological findings and BC incidence. Logistic regression was used to examine the relationship between methylation status and patient age, and to examine the effects of multiple variables. Analyses were performed at three levels; samples from a single breast over time and from a single duct over time and each sample in isolation. Results: A total of 173 DL samples from 98 ducts in 56 breasts were analysed in 34 women (16 BRCA1 and 18 BRCA2 mutation carriers) with a median age of 43 years (range 27- 60). DL fluid was collected from all women on at least one occasion (median 2.5 visits, range 1–5). Five women developed BC on study. Methylation of p16 was strongly associated with a known BRCA1 mutation (p=0.0003, p<0.0001 and p<0.0001 at the breast, duct and sample levels respectively) and was also more likely in women with a previous history of contralateral BC (p=0.0008 and p<0.0001 at the duct and sample level respectively). Independent associations were seen for women who developed BC on study and methylation of p16 and RASSF1A (p16: p=0.0023 at the sample level only) and (RASSF1A: p=0.0760, p=0.0178 and p<0.0001- at the breast, duct and sample level respectively). Conclusions: The methylation pattern in a panel of genes could be used as a biomarker for risk of future breast cancer. In addition p16 methylation may be a predictor of BRCA1 mutation status. Further research is required to corroborate these findings as the numbers recruited for this study are small with a short duration of clinical follow up.

No significant financial relationships to disclose.

Inhibition of colon tumor metastasis in an orthotopic nude mouse model with the dual selective Src/Abl kinase inhibitor, AZD0530

14032

Background: Colorectal cancer is the leading cause of cancer deaths in the USA, largely due to metastatic disease in the liver. The specific activity of the non-receptor protein tyrosine kinase, Src, is increased during colon tumor progression and contributes to metastasis; thus, Src inhibitors may have efficacy in the treatment of advanced-stage colon cancer. AZD0530 is a potent, orally available Src/Abl kinase inhibitor currently in clinical trials. Methods: We examined the effects of AZD0530 alone and in combination with oxaliplatin on two colon tumor cell lines, KM12L4 and LS174T in vitro and in orthotopic nude mouse models. AZD0530 inhibits in vitro proliferation and cellular migration of KM12L4 and LS174T, and decreases phosphorylation of the Src substrates FAK and paxillin in a dose- dependent manner. To examine the ability of AZD0530 to affect colon cancer growth and metastasis in a nude mouse model, we inoculated 1x106 cells into the cecum of nude mice. After 2 weeks, mice were treated with vehicle (n=12), AZD0530 alone (n=13; 25mg/kg/day by oral gavage), oxaliplatin alone (n=13; 5mg/kg/day twice weekly), or AZD0530 and oxaliplatin (n=13). Mice were sacrificed after 4 weeks of treatment. Results: Tumor incidence in all groups of mice was greater than 80%. Mice treated with AZD0530 had an average cecal tumor weight of 0.26 g compared with 0.32 g for control (P=0.24). In contrast, the incidence of liver metastases was reduced by 50% in mice treated with AZD0530 alone or oxaliplatin alone, and no mice developed pathologically evident liver metastases when the combination of inhibitors was used. Furthermore, in mice that developed liver metastases, AZD0530 decreased the size of these metastases 9-fold compared with control. Immunohistochemical analysis of primary cecal tumors demonstrated a decrease in phosphorylated Src (Y418) and FAK (Y861) in AZD0530-treated mice compared with control. Conclusions: These results support further investigation of AZD0530, both alone and in combination, as a new therapeutic strategy for the treatment of advanced colon cancer.

No significant financial relationships to disclose.

Cancer risk management practices of non-carriers within BRCA1/2 mutation positive families in the Kathleen Cunningham Consortium for Research into Familial Breast Cancer (kConFab)

1020

Background: This study prospectively evaluated risk management practices of true BRCA1/2 negative women. Methods: A questionnaire was mailed to 471 non-carriers from mutation positive families 3 years after their enrolment in the kConFab breast cancer (BC) family cohort study. Women who had received their mutation result had pre-test counselling and result disclosure in one of 16 Family Cancer Clinics nationwide. Undertaking mammography more often than 2 yearly (Australian population guidelines), clinical breast examination (CBE) more often than yearly, breast self-examination (BSE) more often than monthly and any trans-vaginal ultrasound (TVU) or CA-125 was considered over screening. Linear logistic regression was used to identify factors (age, marital status, education, parity, ethnicity, place of residence, time since disclosure of result, family history) associated with over screening. Results: 347 women responded (74%); 260 were excluded from this analysis (self-reported not knowing their mutation status, 207; uninformative screening data due to proximity of result disclosure to questionnaire administration, 47; developed cancer, 3; pregnancy, 3), leaving 87 subjects. Mean follow up was 4.4 years. Proportions over-screening were; mammography 53%, CBE 10%, BSE 11%, TVU 10% and CA125 10%. No measured factor was associated with over-utilization of BC screening. Women with > one relative with OC were significantly more likely to over-utilize TVU (OR 8.1, CI 1.6–42 P=0.01) and CA125 (OR 19.6, CI 3.1–121 P=0.001) compared to women with ≤ one relative with OC. One woman underwent bilateral mastectomy and 1 bilateral oophorectomy; none used chemoprevention. Conclusions: A major benefit of learning one′s negative mutation status is that the intensity of risk management practices can be reduced to that appropriate for the general population. However, non-carriers with a strong family history of OC tend to inappropriately use OC screening. The reasons are unclear but need elucidation given the potential for harm. The reasons for over-utilization of mammography in 53% also warrant further study.

No significant financial relationships to disclose.

The DNA sequence and biological annotation of human chromosome 1

The reference sequence for each human chromosome provides the framework for understanding genome function, variation and evolution. Here we report the finished sequence and biological annotation of human chromosome 1. Chromosome 1 is gene-dense, with 3,141 genes and 991 pseudogenes, and many coding sequences overlap. Rearrangements and mutations of chromosome 1 are prevalent in cancer and many other diseases. Patterns of sequence variation reveal signals of recent selection in specific genes that may contribute to human fitness, and also in regions where no function is evident. Fine-scale recombination occurs in hotspots of varying intensity along the sequence, and is enriched near genes. These and other studies of human biology and disease encoded within chromosome 1 are made possible with the highly accurate annotated sequence, as part of the completed set of chromosome sequences that comprise the reference human genome.

FIV-infected cats respond to short-term rHuG-CSF treatment which results in anti-G-CSF neutralizing antibody production that inactivates drug activity

The hematological and virological effects of recombinant human granulocyte colony-stimulating factor (rHuG-CSF) were evaluated in feline immunodeficiency virus (FIV)-infected cats. Six age-matched, FIV-infected cats used in this cross-over study were injected subcutaneously with 5 microg/kg of rHuG-CSF daily for 3 weeks, while six control cats received a placebo. Five of six rHuG-CSF-treated cats had significant increases in neutrophil counts that peaked on days 11-21 of treatment. All rHuG-CSF-treated cats exhibited an increase in myeloid:erythroid ratios of the bone marrow cells without significant changes in lymphocyte, CD4 counts, CD4/CD8 ratios, RBC counts, FIV antibody titers, and FIV loads in peripheral blood, and without clinical and hematological toxicities. Five of six rHuG-CSF-treated cats developed antibodies to rHuG-CSF by 14-21 days of treatment, which correlated with decreasing neutrophil counts and increasing neutralizing antibodies to rHuG-CSF. Three cats re-treated with rHuG-CSF rapidly developed neutralizing antibodies to rHuG-CSF, while one cat also developed neutralizing antibodies to recombinant feline G-CSF (rFeG-CSF). Overall, rHuG-CSF treatment increased neutrophil counts in FIV-infected cats without affecting the infection status of cats. However, long-term use of rHuG-CSF is not recommended in cats because of the neutralizing antibody production to rHuG-CSF that affects the drug activity. In addition, a preliminary finding suggests that repeated treatment cycle can also induce cross-neutralizing antibodies to rFeG-CSF, which may potentially affect the homeostasis of endogenous FeG-CSF.

A quantitative RT-PCR study of the mRNA expression profile of the IGF axis during mammary gland development

We have used quantitative RT-PCR to analyse the mRNA expression profile of the major components of the IGF axis in different stages of murine mammary gland development, including late pregnancy, lactation and involution. We have shown that all the genes studied, IGF-I, IGF-II, IGF receptor (IGFR) and IGF-binding protein (IGFBP)-1 to -6, were expressed in every stage, albeit at greatly differing levels and displaying unique expression profiles between developmental stages. IGF-I was always expressed at significantly higher levels than either IGF-II or IGFR. This suggests that IGF-I may be the more important IGF during mammary morphogenesis. Overall, IGFBP-3 demonstrated the highest level of expression of any of the IGFBP genes throughout all the developmental stages studied. However, within developmental stages, by far the highest level of expression of any of the IGFBPs was that of IGFBP-5 at day 2 of involution; this was almost an order of magnitude higher than any of the other IGFBP levels recorded. This corroborated our previous findings that the levels of IGFBP-5 protein are highly elevated in the involuting mammary gland, and demonstrated that this up-regulation of IGFBP-5 operates at the level of transcriptional control or message stability. Comparison of the expression profile for these different genes would strongly suggest that they are likely to have differential functions throughout mammary gland development, and also highlights potential interactions and co-regulation between different members of this axis. In addition, our results have identified some similarities and differences in the expression of IGFBPs between the mouse mammary epithelial cell line, HC11, and the normal mammary gland which are worthy of study, most notably the differential regulation of IGFBP-2 and the site of expression of IGFBP-4 and -6. Overall, this study has demonstrated the importance and complexity of the IGF axis during mammary gland development and provides a valuable resource for future research in this area.

Use of sequential quadrupling dose regimens to study efficacy of inhaled corticosteroids in asthma

BACKGROUND

Inhaled corticosteroids are widely used to treat asthma. There is a need to be able to compare different inhaled corticosteroids and different doses of an inhaled corticosteroid to determine potency and dose equivalence, but measuring efficacy in a dose related manner is difficult because of their slow onset of action. There is uncertainty about the role of sequential dosing regimens and the best end point for such studies. We have explored the use of sequential quadrupling dose regimens and a range of end points to assess the response to budesonide in subjects with asthma.

METHODS

21 subjects with mild asthma, aged 18-65, took part in a randomised three way crossover study comparing two sequential and one non-sequential regimen, separated by at least 3 weeks. The sequential regimens consisted of increasing doses of inhaled budesonide (100, 400 1600 microg/day) with each dose being given for 1 or 2 weeks; the non-sequential regimen consisted of 1600 microg/day for 2 weeks with end points measured after 1 and 2 weeks. The end points studied included the provocative dose of adenosine monophosphate causing a 20% fall in forced expiratory volume in 1 second (PD20AMP), lung function, symptoms, and bronchodilator use.

RESULTS

There was a dose related increase in PD20AMP with both sequential dose regimens. The increase in PD20AMP ranged from 1.49 doubling doses (DD) following the lowest dose (100 microg/day) to 3.1 DD following the highest dose (1600 microg/day) in the 1 week sequential regimen and from 1.98 to 4.03 DD in the 2 week sequential regimen; standard deviations (SD) for the changes in PD20AMP ranged from 1.3 to 2.6 DD. Changes in forced expiratory volume in 1 second (FEV1) and morning peak expiratory flow rate (PEFR) were dose related but small and more variable (maximum change in FEV1=148 ml, SD 228 ml), while changes in evening PEFR, symptoms, and bronchodilator use were small and not dose related. Change in PD20AMP after budesonide 1600 microg did not differ significantly between regimens.

CONCLUSION

Combining PD20AMP measurements with a sequential regimen of three quadrupling doses of an inhaled corticosteroid given for 1 or 2 weeks provides clear dose-response curves for comparative studies. PD20AMP is a more sensitive end point for this purpose than FEV1, PEFR, symptoms, or relief inhaler use.

Time course of action of two inhaled corticosteroids, fluticasone propionate and budesonide

BACKGROUND

It is important to be able to compare the efficacy and systemic effects of inhaled corticosteroids but their slow onset of action makes it difficult to measure the maximum response to a given dose. Submaximal responses could be compared if the time course of action of the inhaled corticosteroids being compared was similar. We have compared the time course of action of fluticasone and budesonide, measuring response as change in the provocative dose of adenosine monophosphate causing a 20% fall in forced expiratory volume in 1 second (PD20AMP).

METHODS

Eighteen subjects with mild asthma, aged 18-65, took part in a three way randomised crossover study. Subjects took fluticasone (1500 microg/day), budesonide (1600 microg/day), and placebo each for 4 weeks with a washout period of at least 2 weeks between treatments; PD20AMP and forced expiratory volume in 1 second (FEV1) were measured during and after treatment. The time taken to achieve 50% of the maximum response (T50%) was compared as a measure of onset of action.

RESULTS

There was a progressive increase in PD20AMP during the 4 weeks of treatment with both fluticasone and budesonide but not placebo; the increase after 1 and 4 weeks was 2.28 and 4.50 doubling doses (DD) for fluticasone and 2.49 and 3.65 DD for budesonide. T50% was 9.3 days for fluticasone and 7.5 days for budesonide with a median difference between fluticasone and budesonide of 0.1 days (95% CI -1.4 to 2.65). There was a wide range of response to both inhaled corticosteroids but good correlation between the response to fluticasone and budesonide within subjects. FEV1 and morning peak expiratory flow rate (PEFR) increased during the first week of both active treatments and were stable thereafter. There was a small progressive improvement in nocturnal symptoms with both active treatments.

CONCLUSION

PD20AMP was a more sensitive marker of response to inhaled corticosteroid therapy than FEV1 and PEFR. The time course of action of fluticasone and budesonide on PD20AMP is similar, suggesting that comparative studies of their efficacy using 1 or 2 week treatment periods are valid. When a new inhaled corticosteroid becomes available, a pilot study comparing its time course of action with that of an established corticosteroid should allow comparative studies to be performed more efficiently.

Hormonal control of IGF-binding protein (IGFBP)-5 and IGFBP-2 secretion during differentiation of the HC11 mouse mammary epithelial cell line

The mouse mammary epithelial cell line HC11 upregulates the synthesis of beta-casein (a differentiation marker) following treatment with the lactogenic hormone mix dexamethasone, insulin and prolactin (DIP). We demonstrate that the basal levels of IGF-binding protein (IGFBP)-5 secreted by undifferentiated HC11 cells are upregulated 10-fold during DIP-induced cellular differentiation whereas the level of the other IGFBP species secreted by HC11 cells (IGFBP-2) is downregulated during this process. As previously reported, the combination of all three of these hormones is required for synthesis of the differentiation marker beta-casein, whereas basal IGFBP-5 secretion is evident in the absence of any hormonal treatment and, unlike beta-casein, secretion of this protein can be stimulated by binary combinations of the hormones (although maximal levels of IGFBP-5 are achieved in the presence of all three lactogenic hormones). Additionally, levels of IGFBP-5 can be increased by DIP treatment under conditions (non-competency of HC11 cultures or presence of epidermal growth factor) where DIP treatment does not increase synthesis of beta-casein. For IGFBP-2, dexamethasone is a potent inhibitor of secretion whilst prolactin stimulated the secretion of this binding protein into the medium. For the IGFBP axis in HC11 cells we conclude that, although the levels of IGFBP-5 and -2 are influenced by the state of cellular differentiation, the hormonal regulation of the levels of these IGFBP species can be dissociated from the regulation of beta-casein synthesis. In a further series of experiments we demonstrate that IGF-I is able to replace insulin in the DIP lactogenic hormone mix and by the use of a specific IGF-I receptor blocking antibody indicate that the action of IGF-I is mediated through the cell surface IGF-I receptor and not by cross-reaction of IGF-I ligand at the insulin receptor. We discuss our data in the context of the potential role of the IGF axis in the process of cell differentiation and illustrate the significance of our findings in the context of the physiology and life cycle of the mammary epithelial cell.

Genetic toxicity of a standardized mixture of citrus polymethoxylated flavones

Flavonoids are a ubiquitous family of phytochemicals that display a variety of biological effects, both beneficial and adverse depending on the individual compound. Certain flavonoids are genotoxic while others inhibit the genotoxicity of other mutagens. In the present studies, the mutagenicity of a mixture of polymethoxylated flavones (PMFs) purified from citrus peel oil was evaluated. The mixture consisted of nobiletin (32.5%), 3,3',4',5,6,7,8-heptamethoxyflavone (25.0%), tangeretin (14.0%), trimethylscutellarein (9.1%), sinensetin (3.9%), 5-demethyl-nobiletin (2.8%), hexa-O-methylquercetagetin (3.3%), 5-demethyl-tetramethylscutellarein (0.7%), 5-hydroxy-3,3',4',6,7,8-hexamethoxyflavone (0.7%), and a small quantity of unidentified flavonoid compounds (3.9%). In vitro addition of the PMF mixture over a concentration range that spanned four log doses (0.0005-5.0 mg/plate) did not reveal any evidence of mutagenicity in five bacterial tester strains (Salmonella typhimurium TA98, TA100, TA102, TA1535 and TA1537) either in the absence or presence of S9 activation. The PMF mixture exhibited a statistically significant increase in mutagenicity of L5178Y tk(+/-) mouse lymphoma cells at 0.05 (38.5 x 10(-6); P<0.05) and 0.1 mg/ml (61 x 10(-6); P<0.01) compared with vehicle-treated controls (mutation frequency=19.7 x 10(-6)). However, these responses were within historical values observed in negative control cultures and extremely small compared to the positive control (EMS 0.5 microl/ml; 1685.3 x 10(-6)). Furthermore, in the presence of S9 there was no indication of genetic toxicity in L5178Y tk(+/-) cells. These results demonstrate that the PMF mixture is not genotoxic in in vitro assay systems.

Normal female anal sphincter: difficulties in interpretation explained

PURPOSE

Our aims were to quantify the nature, characteristics, and frequency of variations in female anal sphincter anatomy.

METHODS

Nulliparous patients from the antenatal clinic and healthy volunteers of both genders were studied. Sphincter length was determined by the position of the puborectalis sling. Defects in the external anal sphincter were defined at each level and recorded in degrees. Cylindric longitudinal images of the endoanal scans were created by a three-dimensional-representation software package. Manometry was performed by a pull-through technique.

RESULTS

Fifty-seven nulliparous patients and 18 healthy volunteers were included in the study. The mean age was 39 years for males and 28.35 years for females. There was no significant difference in overall sphincter length or in the internal anal sphincter length as a percentage of overall sphincter length between genders. All nine males had a complete ring of external anal sphincter along the full sphincter length. In the external anal sphincter below the level of the puborectalis sling, a natural gap occurred in 43 nulliparous (75 percent) and all 9 female volunteers. The greater the size of the defect, the greater its extent (mean 1.33 cm for >90 degrees and 1.16 cm for <90 degrees; chi-squared P = 0.008, eight degrees of freedom). Manometry provided confirmatory evidence of the gaps seen. Anal manometry was analyzed by Mann-Whitney U test for continuous nonparametric data and t-test for comparison between genders.

CONCLUSION

The female sphincter has a variable natural defect occurring along its anterior length. This makes interpretation of the isolated endoanal ultrasound difficult and explains previous overreporting of obstetric sphincter defects.

Immunotoxicity of a standardized citrus polymethoxylated flavone extract

Polymethoxylated flavones (PMFs) from citrus inhibit production of TNF-alpha and other pro-inflammatory cytokines. As TNF-alpha also modulates NK cell activity, the current studies were conducted to assess the potential for a standardized citrus PMF mixture to suppress humoral and innate immune functions. PMFs were isolated from orange peel oil using a procedure that obtained a consistent mixture of PMFs both in identity and proportion. The mixture consisted of nobiletin (30.7%), 3,3',4',5,6,7,8-heptamethoxyflavone (27.9%), trimethylscutellarein (14.5%), tangeretin (10.4%), sinensetin (5.8%), 5-demethyl-nobiletin (2.0%), hexa-O-methylquercetagetin (1.3%), 5-demethyl-tetramethylscutellarein (0.6%), and other flavonoids (2.7%). To assess the effect of the PMF mixture on humoral immune responses, female B(6)C(3)F(1) mice (n=8) were exposed to the PMF by gavage at 5, 50, 150 and 500 mg/kg/day for 28 days. On day 25, mice were sensitized to sRBC by tail vein injection and AFC response determined 4 days later. Humoral immunity was insensitive to suppression following exposure to all concentrations of the PMF mixture. Suppression of NK cell activity was observed only following 500 mg/kg/day for 28 days. Body weights were not affected by exposure to any concentration of the PMF mixture in sRBC immunized or non-immunized mice. However, in sRBC-immunized mice, higher concentrations of PMF were associated with a statistically insignificant increase in spleen weight (P>0.05). No change in spleen weight was observed in non-immunized mice. As anticipated, based on previously published in vitro observations, long-term, high-dose exposure to a standardized mixture of citrus PMFs caused a mild suppression of NK cell activity; however, humoral immunity was not sensitive to suppression at the same exposure levels.