Dexmedetomidine provides cortical neuroprotection: impact on anaesthetic-induced neuroapoptosis in the rat developing brain

BACKGROUND

Recent evidence has demonstrated the anti-apoptotic of dexmedetomidine in different brain injury models. Herein, we investigated whether dexmedetomidine could directly protect against cortical injury in vitro and in vivo.

METHODS

Apoptosis was induced by staurosporine or wortmannin treatment in cortical neuronal cultures in vitro or by 6 h of isoflurane (0.75%) administration to post-natal day 7 rat pups in vivo. Dexmedetomidine was then applied in escalating doses to assess the neuroprotective potential of this agent. Cell survival was quantified using an MTT assay in vitro and in vivo apoptosis was assessed using cleaved caspase-3 immunohistochemistry. Cortical Western blots were conducted for the cellular survival proteins Bcl-2 and phosphorylated extracellular signal-regulated protein kinase (pERK)1 and 2.

RESULTS

In vitro dexmedetomidine dose-dependently prevented both staurosporine- and wortmannin-induced injury in cortical neuronal cultures, indicating that dexmedetomidine can prevent apoptosis when applied directly. In vivo isoflurane induced cortical neuroapoptosis compared with air (327+/-80 vs. 34+/-9 caspase-3-positive neurons; P<0.05). Dexmedetomidine inhibited isoflurane-induced caspase-3 expression (P<0.05), although the protection achieved did not completely attenuate the isoflurane injury (P<0.05 vs. air). Isoflurane treatment decreased Bcl-2 and pERK protein expression relative to air, an effect reversed by dexmedetomidine treatment.

CONCLUSIONS

Dexmedetomidine prevents cortical apoptosis in vitro and in vivo. However, using higher doses of dexmedetomidine does not further increase protection against isoflurane injury in the cortex than previously observed.

Echinoside A, a new marine-derived anticancer saponin, targets topoisomerase2alpha by unique interference with its DNA binding and catalytic cycle

BACKGROUND

Echinoside A was isolated from sea cucumber. This study demonstrates its anticancer effects and its mechanisms of action.

MATERIALS AND METHODS

Anticancer effects of echinoside A were evaluated in vitro and in vivo. TUNEL and DNA fragmentation assays were applied to examine its ability to induce apoptosis. A series of biochemical assays were applied to investigate the inhibition of echinoside A on topoisomerase2alpha (Top2alpha). Molecular docking analyses were used to demonstrate the direct interaction between echinoside A and Top2alpha.

RESULTS

Echinoside A inhibited the growth of tumors in mouse models and human prostate carcinoma xenografts in nude mouse models. Echinoside A shows the unique characteristics of inhibiting the noncovalent binding of Top2alpha to DNA by competing with DNA for the DNA-binding domain of the enzyme and of interfering predominantly with the Top2alpha-mediated prestrand passage cleavage/religation equilibrium over with the poststrand passage one. These features distinguish echinoside A from other known Top2alpha inhibitors. As a result, echinoside A induced DNA double-strand breaks in a Top2-dependent manner.

CONCLUSION

Echinoside A targets Top2alpha by unique interference with the binding of Top2 to DNA and by imparing the Top2-mediated DNA cleavage and religation, exerting potent in vitro and in vivo antitumor activities.

Meta-analysis of adjuvant chemotherapy after radical surgery for advanced gastric cancer

BACKGROUND

There is no consensus of opinion about postoperative adjuvant chemotherapy after radical surgery for advanced gastric cancer. This is a meta-analysis of the published results of relevant randomized clinical trials (RCTs).

METHODS

Electronic databases from January 1998 to December 2007 were searched and 12 RCTs were selected. These included a total of 3809 patients. The hazard ratio (HR) for overall survival was calculated.

RESULTS

The pooled HR for overall survival was 0.78 (95 per cent confidence interval 0.71 to 0.85) in favour of chemotherapy. Subgroup analysis showed that the advantage of chemotherapy was not influenced by depth of tumour infiltration, status of lymph node metastasis, type of lymphadenectomy, geographical distribution of patients or route of drug administration.

CONCLUSIONS

Postoperative chemotherapy can improve overall survival after radical surgery for gastric cancer; there is no standardized chemotherapy regimen. Japanese-style D2 radical surgery plus oral 5-fluorouracil appears an effective treatment at present.

Meta-analysis of adjuvant chemotherapy after radical surgery for advanced gastric cancer

BACKGROUND

There is no consensus of opinion about postoperative adjuvant chemotherapy after radical surgery for advanced gastric cancer. This is a meta-analysis of the published results of relevant randomized clinical trials (RCTs).

METHODS

Electronic databases from January 1998 to December 2007 were searched and 12 RCTs were selected. These included a total of 3809 patients. The hazard ratio (HR) for overall survival was calculated.

RESULTS

The pooled HR for overall survival was 0.78 (95 per cent confidence interval 0.71 to 0.85) in favour of chemotherapy. Subgroup analysis showed that the advantage of chemotherapy was not influenced by depth of tumour infiltration, status of lymph node metastasis, type of lymphadenectomy, geographical distribution of patients or route of drug administration.

CONCLUSIONS

Postoperative chemotherapy can improve overall survival after radical surgery for gastric cancer; there is no standardized chemotherapy regimen. Japanese-style D2 radical surgery plus oral 5-fluorouracil appears an effective treatment at present.

Breast cancer risks in women with a family history of breast or ovarian cancer who have tested negative for a BRCA1 or BRCA2 mutation

Genetic testing for mutations in BRCA1 and BRCA2 is available in Canada for women with a significant family history of breast cancer. For the majority of tested women, a BRCA1 or BRCA2 mutation is not found, and counselling regarding breast cancer risk is based on the review of the pedigree. In this prospective study, we estimate breast cancer risks in women with a family history of breast cancer and for whom the proband tested negative for a mutation in BRCA1 or BRCA2. Families with two or more breast cancers under the age of 50 years, or with three cases of breast cancer at any age, and who tested negative for a BRCA1 or BRCA2 mutation were identified. Follow-up information on cancer status was collected on all first-degree relatives of breast cancer cases. The standardised incidence ratios (SIRs) for breast cancer were calculated by dividing the observed numbers of breast cancer by the expected numbers of breast cancers, based on the rates in the provincial cancer registries. A total of 1492 women from 365 families were included in the analyses. The 1492 first-degree relatives of breast cancer cases contributed 9109 person-years of follow-up. Sixty-five women developed breast cancer, compared to 15.2 expected number (SIR=4.3). The SIR was highest for women under the age of 40 (SIR=14.9) years and decreased with increasing age. However, the absolute risk was higher for women between the age of 50 and 70 (1% per year) years than for women between 30 and 50 (0.4% per year) years of age. There was no elevated risk for ovarian, colon or any other form of cancer. Women with a significant family history of breast cancer (ie, two or more breast cancers under the age of 50 years, or three or more breast cancers at any age), but who test negative for BRCA mutations have approximately a four-fold risk of breast cancer. Women in these families may be candidates for tamoxifen chemoprevention and/or intensified breast screening with an MRI.

Rapid progression of prostate cancer in men with a BRCA2 mutation

Men with BRCA2 mutations have been found to be at increased risk of developing prostate cancer. There is a recent report that BRCA2 carriers with prostate cancer have poorer survival than noncarrier prostate cancer patients. In this study, we compared survival of men with a BRCA2 mutation and prostate cancer with that of men with a BRCA1 mutation and prostate cancer. We obtained the age at diagnosis, age at death or current age from 182 men with prostate cancer from families with a BRCA2 mutation and from 119 men with prostate cancer from families with a BRCA1 mutation. The median survival from diagnosis was 4.0 years for men with a BRCA2 mutation vs 8.0 years for men with a BRCA1 mutation, and the difference was highly significant (P<0.01). It may be important to develop targeted chemotherapies to treat prostate cancer in men with a BRCA2 mutation.

Sensitivity of surveillance mammography for contralateral breast cancers and ipsilateral recurrences in survivors under 50

11009

Background: Annual mammography is currently the gold standard for surveillance of breast cancer survivors for both ipsilateral recurrence and contralateral new primaries. The risk of either of these events occurring has been found to be inversely proportional to age and is at least 1% per year if breast cancer was diagnosed before age 50. (Chen et al 1999) (Komoike et al 2006). However, the sensitivity of screening mammography is significantly lower in young women. We therefore sought to determine the effectiveness of surveillance mammography according to age of diagnosis using a prospective database. Methods: The Henrietta Banting Database prospectively follows all new cases of operable breast cancer diagnosed from 1987 - 2004 at Women’s College Hospital. From the 1992 women in the database, we selected all patients diagnosed before age 60 who subsequently developed non-metastatic contralateral cancers (n=71 ) or ipsilateral recurrences (n=11 ). Records were obtainable for 59 of these 82 patients. Results: Method of detection and stage of diagnosis are listed in table below for the 59 patients according to age of diagnosis of second cancers. Overall, mammography was less effective at detecting contralateral and recurrent breast cancers in younger women, detecting only 24% of these cancers in women under 50 compared to 74% in patients 50 and older (Chi-Square, p<0.001). In addition, 77% of patients under 50 whose second cancers were detected by methods other than mammography had negative surveillance mammograms in the 15 months prior to diagnosis. Conclusion: Since mammography detected only 24% of second primary breast cancers/ recurrences in survivors < age 50 and almost one third of all detected cancers were locally advanced, more sensitive imaging modalities such as breast MRI should be considered for surveillance of young survivors.

[Table: see text]

No significant financial relationships to disclose.

A survey of preventive measures among BRCA1 mutation carriers from Poland

Among women with a BRCA1 mutation, the lifetime risks of breast and ovarian cancer are elevated. Several measures for reducing cancer risk in carriers of BRCA1 mutations have been proposed, including prophylactic surgery and tamoxifen chemoprevention. It is not yet known to what extent women with mutations have adopted these various preventive measures. We surveyed 414 Polish women with a BRCA1 mutation who had received counseling about various preventive strategies. Each woman completed a survey for a minimum of 18 months after receiving her genetic result. A high proportion of women reported having had an oophorectomy to reduce breast and ovarian cancer risk (49.1%). In contrast, only 11% had taken tamoxifen and only 5% had undergone a preventive mastectomy. Most of the women (81%) had a screening mammogram during the follow-up period. Oral contraceptives and breastfeeding are believed to protect against ovarian cancer, but only 9% of women had taken the birth control pill for 3 years or more and 27% had breastfed for 1 year or more. In summary, approximately one-half of Polish women with a BRCA1 mutation had taken an active step to reduce their risk of breast cancer within 18 months of receiving a positive result. A greater effort should be made to promote breastfeeding and use of oral contraceptive as risk-reducing measures.

Epidermal growth factor receptor (EGFR) mutation rate in advanced ovarian cancer (AOC): Results of a prospective study in Caucasian patients (pts)

13127

Background: The EGFR is over expressed in 55% to 98% of advanced epithelial ovarian carcinoma. Different studies demonstrated EGFR status as an independent prognostic factor for OC. Recent studies in non small cell lung cancer suggest that the presence of the clinical response to tyrosine kinase inhibitors (e.g. ZD 1839) correlates with the somatic mutations in the kinase domain of EGFR, exons 18–21. For pts with OC data are not available on EGFR gene mutation. Methods: Shock-frozen samples from 32 patients (pts) with primary of ovarian cancer were stratified in two groups according to disease-free interval: ≤6 months (17 pts.) and <6 months (15 pts.). All pts were prospectively collected within Tumor bank Ovarian Cancer Project. Patient collective consisted only from west European Caucasian women. Additionally, 9 commercial available ovarian cancer cell lines (TOV-90, TOV-112D, TOV-21G, OVCAR-3, A2780, A2780 ADR, ES-2, SK-OV-3, and Caov-3) and 32 established ovarian cancer lines were analysed. Exon sequencing of genomic DNA was used to detect L858R deletion mutations of EGFR within exons 21 of the kinase domain. PCR and capillary electrophoresis (Chip-Format) were used to analyse 15 bp deletion in Exon 19. We focused on descriptive analysis. The Log-Rank test was applied to confirm statistically significance (p-value of <0.05). Results: Overall, 74.6% of the pts. were diagnosed FIGO stage III-IV. Median follow-up period was: 14.17 month (range: 2–42 months). Whether in cell lines, nor in tumor samples, stratified to response of platinum therapy any mutation of EGFR gene was observed. Conclusions: Our study indicates that the prevalence of mutation in the kinase domain of EGFR, exons 19 and 21 seems to be very low in pts. with AOC. Further studies should investigate other ethical groups of pts.

No significant financial relationships to disclose.

Effects of polymorphism (plm) in interleukin (IL) 1 and IL10 genes on surgery outcome in ovarian cancer (OC)

20094

Background: IL1 and IL10 are overexpressed in 55% to 98% of advanced epithelial OC. Different studies demonstrated IL1 and IL10 as independent prognostic factors for OC. This study was performed to investigate the influence of plms of IL-1A, IL-1B and IL-10 gene on the occurrence tumor biology of OC. Methods: In a prospective, monocentric, case-control study 147 pts with OC (71 pts with primary OC and 77 pts with recurrent OC) and 129 pts with no history of malignancies were genotyped for plms of the IL-1 gene (IL-1A -889 T/C and IL-1B -511 C/T promoter) and IL-10 gene (IL-10 -1082 G/A, -819 C/T and -592 C/A). All pts were collected within Tumor bank Ovarian Cancer Project. Genomic DNA fragments were amplified by PCR and the allele sequences were obtained by pyrosequencing. We analyzed significance using the Chi-Square by Pearson and Fisher’s exact test. Statistical significance was determined by Mann-Whitney test. A two-tailed p value <0.05 was considered statistically significant. Overall survival (OS) was estimated using the Kaplan-Meier product limited method. Results: The median age of the pts with OC was 55.5 years (range 19–81 y). Median follow-up period was: 31.5 months (range: 1–225 mo). There were no significant associations between allelic frequencies for IL-1A and IL-1B in OC. The IL-10 plm in -819 and -592 positions significantly correlates with the postoperative residual tumor (p = 0.036 and p = 0.035 respectively). For pts without any postoperative tumor residuals the most encountered genotype was C/C at −819 and −592. The same genotype was associated in univariate analysis with a better OS (95% CI = 37.5–94.5 and 40.8–91.2, respectively). In the multivariate models there was no correlation between any plms and disease-free and OS. Postoperative residual tumor (OR =0.202, 95% CI = 0.088–0.462, p = 0.0001) and ascites volume (OR = 0.106, 95% CI = 0.046–0.248, p = 0.026) were independent prognostic factors for reduced OS. Conclusions: Plm of IL1A, IL1B, IL10 showed no association with occurrence of OC. IL-10 promoter plm may influence the tumor biology and could potentially predict results of radical surgery.

No significant financial relationships to disclose.

Active c-Src has prognostic and therapeutic value in ER-negative breast cancer

10063

Background: Approximately 33% of newly diagnosed breast cancers lack ER and these tend to have a worse prognosis as compared to ER-positive breast cancers. Therapeutic options are limited as they are not responsive to antihormonal therapy and often develop resistance to chemotherapies. We have recently shown that activation of the nonreceptor tyrosine kinase protein c-Src leads to the accelerated ER degradation in ER-negative breast cancers. This study performs an immunohistochemical analysis of activated c-Src in a large cohort of primary human breast carcinomas to a) assess its prognostic significance and b) correlate its relationship to the ER status of breast cancers. Methods: A total of 916 patients with breast cancer diagnosed between 1987 and 1997 had clinicopathological data and paraffin-embedded tumor tissues for the study. Tissue microarrays were constructed. A four point scoring system based on immunostaining intensity was used to grade the levels of active phosphorylated c-Src. Grading was done by one pathologist. Statistical analysis was used to assess the prognostic significance of activated c-Src and its relationship to other prognostic variables. Results: Median follow-up was 7.31 years. Active c-Src grade was inversely correlated with ER status (p=0.004) and predicted for treatment with chemotherapy (p=0.002) and lack of treatment with Tamoxifen (p=0.007). Patients with greater levels of c-Src tended to be younger (p=0.004) and had higher Bloom Richardson scores for their tumors (p=0.004). Higher levels of c-Src also predicted for for shorter timing to distant recurrence (p=0.01) and shorter timing to death (p=0.04). There was a trend towards a shorter timing to regional recurrence with higher levels of c-Src but the relationship was not statistically significant (p=0.08). Conclusion: This study supports the hypothesis that the presence of active, phosphorylated c-Src contributes to the development of ER-negative status in breast cancers. The presence of c-Src also is associated with other poor prognostic factors and contributes to a worse prognostic outcome. This study suggests that c-Src inhibitors may be a novel therapeutic strategy for the treatment of ER-negative breast cancers.

No significant financial relationships to disclose.

A proteomic analysis reveals the loss of expression of the cell death regulatory gene GRIM-19 in human renal cell carcinomas

Gene associated with retinoid interferon-induced mortality (GRIM)-19, an inhibitor of transcription factor STAT3, was originally identified as a critical regulatory protein in a genetic screen that was designed to identify the gene products necessary for Interferon (IFN)-beta- and retinoic acid-induced cell death. Over expression of GRIM-19 activates cell death. Conversely, inactivation of its expression promotes cell growth. STAT3 is a transcription factor that regulates gene expression in response to multiple extra cellular growth factors. In contrast to its normal feedback inhibition, a constitutive activation of STAT3 has been documented in several tumors. Although many STAT3-inhibitors are described, their relevance to human cancer is unclear. In an attempt to define the molecular alterations associated with human renal cell carcinoma (RCC) using mass spectrometry, we have discovered that expression of GRIM-19 is lost or severely depressed in a number of primary RCC and in some urinogenital tumors. Using an RCC cell line, we show that down regulation of GRIM-19 promotes tumor growth via an augmentation of STAT3-dependent gene expression. These studies for the first time show a tumor-suppressor like activity of GRIM-19.

Cancer risks in first degree relatives of BRCA1 mutation carriers: effects of mutation and proband disease status

BACKGROUND

Mutations in the BRCA1 (MIM 113705) gene are found in many families with multiple cases of breast and ovarian cancer, and women with a BRCA1 mutation are at significantly higher risk of developing breast and ovarian cancer than are the general public.

METHODS

We obtained blood samples and pedigree information from 3568 unselected cases of early-onset breast cancer and 609 unselected patients with ovarian cancer from hospitals throughout Poland. Genetic testing was performed for three founder BRCA1 mutations. We also calculated the risk of breast and ovarian cancer to age 75 in the first degree relatives of carriers using Kaplan-Meier methods.

RESULTS

The three founder BRCA1 mutations were identified in 273 samples (187 with 5382insC, 22 with 4153delA, and 64 with C61G). A mutation was present in 4.3% of patients with breast cancer and 12.3% of patients with ovarian cancer. The overall risk of breast cancer to age 75 in relatives was 33% and the risk of ovarian cancer was 15%. The risk for breast cancer was 42% higher among first degree relatives of carriers of the C61G missense mutation compared to other mutations (HR = 1.42; p = 0.10) and the risk for ovarian cancer was lower than average (OR = 0.26; p = 0.03). Relatives of women diagnosed with breast cancer had a higher risk of breast cancer than relatives of women diagnosed with ovarian cancer (OR = 1.7; p = 0.03).

CONCLUSIONS

The risk of breast cancer in female relatives of women with a BRCA1 mutation depends on whether the proband was diagnosed with breast or ovarian cancer.

Expression of estrogen receptor-related receptor isoforms and clinical significance in endometrial adenocarcinoma

Estrogen receptor-related receptors (ERRs) are members of orphan nuclear receptors closely related to the estrogen receptors (ERs). Researches showed that the ERRs bound to estrogen response elements and interfered in the ER signal pathway. Therefore, it might be associated with estrogen-dependent diseases. The purpose of this study was to explore whether ERRs were involved in the tumorigenesis of endometrial adenocarcinoma. We examined the expression of ERRs in endometrial adenocarcinoma and normal endometrium using semiquantitative reverse transcription-polymerase chain reaction and immunohistochemistry. Clinicopathologic features including FIGO stage, histologic grade, myometrial invasion, and nodal metastasis were reviewed. Results showed that messenger RNA (mRNA) levels of ERRalpha, ERRbeta, and ERRgamma were positively associated with the immunoreactivities (P= 0.009, P= 0.014, and P= 0.001, respectively). The expression rate and relative level of ERRalpha mRNA in ERalpha-positive endometrial adenocarcinomas were lower than in normal endometriums (P= 0.049 and P= 0.023), whereas the relative level of ERRgamma mRNA in ERalpha-positive endometrial adenocarcinomas was higher than in normal endometriums (P= 0.014). Expression of ERRalpha mRNA was positively correlated with FIGO stage (P= 0.019) and myometrial invasion (P= 0.043). A negative correlation was observed between expression of ERRgamma mRNA and nodal metastasis (P= 0.021). Results suggested that ERRalpha and ERRgamma might participate in the tumorigenesis of endometrial adenocarcinoma. ERRalpha and ERRgamma are promising to be new prognostic factors in endometrial adenocarcinoma.

Comorbid conditions in men with ED before and after ED diagnosis: a retrospective database study

Although erectile dysfunction (ED) has been considered a complication of other medical conditions, clinicians and researchers suggest that ED may serve as a clinical marker of vascular health. This retrospective claims study examined the prevalence of predefined comorbid conditions in men with ED (N=301 994) in the 12 months before and the 6 months following ED diagnosis. Consistent with previous research, comorbid conditions were prevalent among men with ED. Comorbid conditions were most often diagnosed before an ED diagnosis, although new diagnoses in the 6 months following an ED diagnosis were common and occured more frequently than new diagnoses in a matched sample of men without ED during the same period. Differences by age, region and insurance coverage for ED medications were also examined. Findings support previous research that suggests ED may serve as a marker for previously undetected comorbid conditions.

Neuroprotection and neurogenesis: Modulation of cornus ammonis 1 neuronal survival after transient forebrain ischemia by prior fimbria-fornix deafferentation

Severe transient forebrain ischemia causes selective neuronal death in the hippocampal cornus ammonis 1 region. We tested the hypothesis that fimbria-fornix deafferentation can provide long-term protection to cornus ammonis 1 neurons and modulate neurogenesis following ischemia. Fimbria-fornix lesion or sham-fimbria-fornix lesion was performed on Wistar rats 13 days prior to 10 min forebrain ischemia or sham ischemia. Temperature was regulated and rats survived for 7, 14 or 28 days. Immunofluorescent bromodeoxyuridine and neuron specific nuclear protein staining and immunochemistry terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling staining were performed. At 7 days after ischemia, 73%+/-14% of cornus ammonis 1 neurons were damaged, while deafferentation reduced the injury to 36%+/-17% of cornus ammonis 1 neurons. This protection persisted for at least 28 days. Ischemia significantly increased the number of bromodeoxyuridine-positive cells (85-90 cells/section in stroke group vs. 6 to 11 cells/section in normal or sham stroke group), with very few terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling-stained cells adjacent to the hippocampal cornus ammonis 1. Fimbria-fornix lesioning followed by ischemia increased the percentage of new neurons 13-fold over ischemia alone and 6.5-fold over sham lesion plus ischemia. The results indicate that fimbria-fornix deafferentation provides long-term neuroprotection in cornus ammonis 1 following forebrain ischemia and promotes neurogenesis after ischemic insults.

A Web-based program for coding open-ended response protocols

A Web-based coding application was designed to improve coding efficiency and to provide a systematic means of evaluating responses to open-ended assessments. The system was developed for use by multiple raters to assign open-ended responses to predetermined categories. The application provides a software environment for efficiently supervising the work of coders and evaluating the quality of the coding by (1) systematically presenting open-ended responses to coders, (2) tracking each coder's categorized responses, and (3) assessing interrater consistency at any time in order to identify coders in need of further training. In addition, the application can be set to automatically assign repeated responses to categories previously identified as appropriate for those responses. To evaluate the efficacy of the coding application and to determine the statistical reliability of coding open-ended data within this application, we examined data from two empirical studies. The results demonstrated substantial interrater agreement on items assigned to various categories across free and controlled association tasks. Overall, this new coding application provides a feasible method of reliably coding open-ended data and makes the task of coding these data more manageable.

Breast-feeding and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers

BACKGROUND

Several studies have reported that the risk of breast cancer decreases with increasing duration of breast-feeding. Whether breast-feeding is associated with a reduced risk of hereditary breast cancer in women who carry deleterious BRCA1 and BRCA2 mutations is currently unknown.

METHODS

We conducted a case-control study of women with deleterious mutations in either the BRCA1 or the BRCA2 gene. Study participants, drawn from an international cohort, were matched on the basis of BRCA mutation (BRCA1 [n = 685] or BRCA2 [n = 280]), year of birth (+/-2 years), and country of residence. The study involved 965 case subjects diagnosed with breast cancer and 965 control subjects who had no history of breast or ovarian cancer. Information on pregnancies and breast-feeding practices was derived from a questionnaire administered to the women during the course of genetic counseling. Conditional logistic regression analyses were used to estimate odds ratios (ORs) for the risk of breast cancer. All statistical tests were two-sided.

RESULTS

Among women with BRCA1 mutations, the mean total duration of breast-feeding was statistically significantly shorter for case subjects than for control subjects (6.0 versus 8.7 months, respectively; mean difference = 2.7 months, 95% confidence interval [CI] = 1.4 to 4.0; P<.001). The total duration of breast-feeding was associated with a reduced risk of breast cancer (for each month of breast-feeding, OR = 0.98, 95% CI = 0.97 to 0.99; P(trend)<.001). Women with BRCA1 mutations who breast-fed for more than 1 year were less likely to have breast cancer than those who never breast-fed (OR = 0.55, 95% CI = 0.38 to 0.80; P =.001), although no such association was seen for BRCA2 (OR = 0.95, 95% CI = 0.56 to 1.59; P =.83).

CONCLUSIONS

Women with deleterious BRCA1 mutations who breast-fed for a cumulative total of more than 1 year had a statistically significantly reduced risk of breast cancer.

Cloning of hypoxia-inducible factor 1alpha cDNA from a high hypoxia tolerant mammal-plateau pika (Ochotona curzoniae)

Hypoxia-inducible factor 1 is a transcription factor composed of HIF-1alpha and HIF-1beta. It plays an important role in the signal transduction of cell response to hypoxia. Plateau pika (Ochotona curzoniae) is a high hypoxia-tolerant and cold adaptation species living only at 3000-5000 m above sea level on the Qinghai-Tibet Plateau. In this study, HIF-1alpha cDNA of plateau pika was cloned and its expression in various tissues was studied. The results indicated that plateau pika HIF-1alpha cDNA was highly identical to those of the human (82%), bovine (89%), mouse (82%), and Norway rat (77%). The deduced amino acid sequence (822bp) showed 90%, 92%, 86%, and 86% identities with those of the human, bovine, house mouse, and Norway rat, respectively. Northern blot analyses detected two isoforms named pLHIF-1alpha and pSHIF-1alpha. The HIF-1alpha mRNA was highly expressed in the brain and kidney, and much less in the heart, lung, liver, muscle, and spleen, which was quite different from the expression pattern of mouse mRNA. Meanwhile, a new variant of plateau pika HIF-1alpha mRNA was identified by RT-PCR and characterized. The deduced protein, composed of 536 amino acids, lacks a part of the oxygen-dependent degradation domain (ODD), both transactivation domains (TADs), and the nuclear localization signal motif (NLS). Our results suggest that HIF-1alpha may play an important role in the pika's adaptation to hypoxia, especially in brain and kidney, and pika HIF-1alpha function pattern may be different from that of mouse HIF-1alpha. Furthermore, for the high ratio of HIF-1alpha homology among the animals, the HIF-1alpha gene may be a good phylogenetic performer in recovering the true phylogenetic relationships among taxa.

An improved morphological approach to background normalization of ECG signals

This paper describes an improved morphological approach to remove baseline wander from neonatal electrocardiogram (ECG) signals, with particular emphasis on preserving the ST segment of the original signal. The algorithm consists of two stages of morphological processing. First, the QRS complex and impulsive noise component due to skeletal muscle contractions etc., are detected and removed from the input signal. Second, the corrected QT interval (QTc) and RR interval are used to determine a structuring element. With this structuring element, the same morphological operation as in the first stage is then applied to the QRS-removed signal to obtain and remove the baseline wander. The performance of the algorithm is evaluated with simulated and real ECGs. Compared with an existing morphological method, there is a substantial improvement, especially in reducing distortion of the baseline waveform within the PR and QT intervals.

A colorimetric bead-binding assay for detection of intermolecular interactions

We have developed a new technique that rapidly and reproducibly allows direct visualization of molecular interactions, including receptor-ligand binding. The technique can be easily applied to examine binding between proteins and glycoproteins, or proteins and glycolipids, including gangliosides. In this novel bead-binding assay, the suspected 'ligand' molecule is bound to 0.2- or 1.0- micro m colored FluoSphere beads. These coated beads are then mixed directly with 150- micro m Sepharose or 50- to 75- micro m agarose beads coated with the second 'target' molecule. Binding between molecules is easily detected by immunofluoresence microscopy as colored rosettes or aggregations formed by clustering of the smaller fluorescent beads around the larger non-fluorescent bead. The validity of this technique for glycolipid binding to protein was verified through demonstration of the known interaction between the beta subunit of cholera toxin with ganglioside GM1. The bead-binding technique facilitated the novel observations of interaction between ganglioside GT1b with the alpha5 subunit of alpha5beta1 integrin and the interaction of GM3 with the epidermal growth factor receptor. A modification of this technique, in which the coated beads are bound to protein fixed on plates, allows a quantifiable colorimetric assay of interaction. This versatile and rapid technique will have widespread applications for in vitro systems and may also be useful for in vivo analysis of binding to cell surface receptor molecules.

Transcriptional regulation of mouse delta-opioid receptor gene: role of Ets-1 in the transcriptional activation of mouse delta-opioid receptor gene

Previously, we identified a minimum core promoter of the mouse delta-opioid receptor (DOR) gene. The DOR promoter contains an E-box that binds upstream stimulatory factor and is crucial for the DOR promoter activity in NS20Y cells, a mouse neuronal cell line that constitutively expresses DOR. In the present study, we further analyzed the DOR promoter in NS20Y cells and have demonstrated that transcription factor Ets-1 binds to an Ets-1-binding site overlapping the E-box and trans-activates the DOR promoter by synergizing with upstream stimulatory factor in specific DNA binding. In addition, the Ets-1 DNA-binding domain is sufficient to play the functional role of Ets-1 in trans-activating the DOR promoter. Furthermore, through in vivo cross-linking assays and Northern blot analyses, we have demonstrated that Ets-1 binds to the DOR promoter in the neonatal mouse brain and that overexpressed Ets-1 can significantly enhance the expression of DOR mRNA in primary neonatal mouse neuronal cells. Collectively, our data suggest that Ets-1 functions as a trans-activator of the DOR promoter in the neonatal mouse brain and thus may contribute to the development of the mouse brain DOR system.

Inhibition of integrin-linked kinase/protein kinase B/Akt signaling: mechanism for ganglioside-induced apoptosis

Ganglioside GT1b inhibits keratinocyte attachment to and migration on a fibronectin matrix by binding to alpha(5)beta(1) and preventing alpha(5)beta(1) interaction with fibronectin. The role of gangliosides in triggering keratinocyte apoptosis, however, is unknown. Addition of GT1b to keratinocyte-derived SCC12 cells, grown in serum-free medium but exposed to fibronectin, suppressed Bad phosphorylation, activated caspase-9, and inhibited cyclin D and E expression, resulting in cell cycle arrest at G(1) phase and initiation of apoptosis. The mechanism of GT1b activation of caspase-9 involved inhibition of beta(1) integrin serine/threonine phosphorylation and decreased phosphorylation of both integrin-linked kinase and protein kinase B/Akt at its Ser-473 site, leading to cytochrome c release from mitochondria. Consistently, blockade of GT1b function with anti-GT1b antibody specifically activated the Ser-473 site of Akt, markedly suppressing apoptosis. The ganglioside-induced inhibition of Akt phosphorylation was GT1b-specific and was not observed when cells were treated with other keratinocyte gangliosides, including GD3. These studies suggest that the modulation of keratinocyte cell cycle and survival by GT1b is mediated by its direct interaction with alpha(5)beta(1) and resultant inhibition of the integrin/integrin-linked kinase/protein kinase B/Akt signaling pathway.

A new total synthesis of the marine tunicate alkaloid lepadiformine

[reaction: see text]. A total synthesis of racemic lepadiformine has been achieved via a route that utilizes as key steps a novel stereocontrolled intramolecular spirocyclization of an allylsilane/N-acyliminium ion and the application of our radical-based methodology for production of N-acylimines from o-aminobenzamides.

Fabrication of nanometer-sized electrodes and tips for scanning electrochemical microscopy

A novel method for fabrication of nanometer-sized electrodes and tips suitable for scanning electrochemical microscopy (SECM) is reported. A fine etched Pt wire is coated with polyimide, which was produced by polymerization on the Pt surface initiated by heat. This method can prepare electrodes with effective radii varying from a few to hundreds of nanometers. Scanning electron microscopy, cyclic voltammetry, and SECM were used to characterize these electrodes. Well-defined steady-state voltammograms could be obtained in aqueous or in 1,2-dichloroethane solutions. This method produced the nanoelectrodes with exposed Pt on the apex, and they can also be employed as the nanotips for SECM investigations. Different sizes of Pt nanotips made by this method were employed to evaluate the kinetics of the redox reaction of Ru(NH3)6(3+) on the surface of a large Pt electrode by SECM, and the standard rate constant kappa0 of this system was calculated from the best fit of the SECM approach curve. This result is similar to the values obtained by analysis of the obtained voltammetric data.

Adolescent smoking in Wuhan, China: baseline data from the Wuhan Smoking Prevention Trial

BACKGROUND

This study reports the prevalence of adolescent smoking in the urban and rural areas of Wuhan, China, the capital of Hubei Province, on the Yangtze River in central China.

METHODS

Smoking behavior was examined by age, gender, and urbanicity as part of the Wuhan Smoking Prevention Trial. Subjects included 6994 seventh- to ninth-grade students attending 22 randomly selected schools in urban and rural districts. Outcome measures included lifetime smoking, past-30-day smoking, established smoking (>100 cigarettes in lifetime), and susceptibility to smoking (absence of a firm commitment not to smoke).

RESULTS

Lifetime smoking prevalence was 47% among boys and 18% among girls. Past-30-day smoking prevalence was 16% among boys and 4% among girls. Established smoking prevalence was 2% among boys and 0% among girls. The prevalence of susceptibility to smoking was 31% among boys and 10% among girls. Smoking increased significantly with age (p<.0005). Susceptibility was more prevalent in rural areas than in urban areas (p<.05), but there were no urban-rural differences in lifetime, past 30-day smoking, or established smoking. Trend analyses revealed that smoking increased with age more rapidly among boys than among girls (p<.05). Smoking was more prevalent among rural boys than among urban boys, but it was more prevalent among urban girls than among rural girls (p<.05).

CONCLUSIONS

Adolescent smoking is a significant public health problem in China. Boys are at particularly high risk, as are girls living in urban areas. Effective smoking prevention programs for adolescents, as well as restrictions on tobacco industry marketing and youth access to tobacco, are needed to prevent tobacco-related morbidity and mortality in China.

Epidermal growth factor receptor glycosylation is required for ganglioside GM3 binding and GM3-mediated suppression [correction of suppresion] of activation

Gangliosides are able to bind to the epidermal growth factor receptor and inhibit its activation, but the mechanism of this inhibition is unknown. To address the role of receptor carbohydrates in facilitating interaction with gangliosides, we examined the ability of GM3 to bind the deglycosylated receptor and inhibit its autophosphorylation. Flow cytometry studies demonstrated that deglycosylation of the receptor did not affect its ability to be transported to the cell membrane. In contrast with the native (fully glycosylated) receptor, GM3 did not coimmunoprecipitate with the deglycosylated receptor. Using a novel colorimetric bead binding assay, GM3 was shown to bind well to the immunoprecipitated native receptor but not at all to the deglycosylated receptor. Finally, the addition of GM3 to cells with deglycosylated epidermal growth factor receptors did not result in significant further inhibition of autophosphorylation of the receptor, despite a 10-fold decrease in phosphorylation of the native epidermal growth factor receptor by 200 microM GM3. These studies suggest that ganglioside affects epidermal growth factor receptor activity through a direct interaction that requires receptor glycosylation, and contribute to our understanding of the role of gangliosides in cell membrane function.

Oxygenated carotenoid lutein and progression of early atherosclerosis: the Los Angeles atherosclerosis study

BACKGROUND

Carotenoids are hypothesized to explain some of the protective effects of fruit and vegetable intake on risk of cardiovascular disease. The present study assessed the protective effects of the oxygenated carotenoid lutein against early atherosclerosis.

METHODS AND RESULTS

EPIDEMIOLOGY

Progression of intima-media thickness (IMT) of the common carotid arteries over 18 months was determined ultrasonographically and was related to plasma lutein among a randomly sampled cohort of utility employees age 40 to 60 years (n=480). Coculture: The impact of lutein on monocyte response to artery wall cell modification of LDL was assessed in vitro by quantification of monocyte migration in a coculture model of human intima. Mouse models: The impact of lutein supplementation on atherosclerotic lesion formation was assessed in vivo by assigning apoE-null mice to chow or chow plus lutein (0.2% by weight) and LDL receptor-null mice to Western diet or Western diet plus lutein. IMT progression declined with increasing quintile of plasma lutein (P for trend=0.007, age-adjusted; P=0.0007, multivariate). Covariate-adjusted IMT progression (mean+/-SEM) was 0.021+/-0.005 mm in the lowest quintile of plasma lutein, whereas progression was blocked in the highest quintile (0.004+/-0.005 mm; P=0.01). In the coculture, pretreatment of cells with lutein inhibited LDL-induced migration in a dose-dependent manner (P<0.05). Finally, in the mouse models, lutein supplementation reduced lesion size 44% in apoE-null mice (P=0.009) and 43% in LDL receptor-null mice (P=0.02).

CONCLUSIONS

These epidemiological, in vitro, and mouse model findings support the hypothesis that increased dietary intake of lutein is protective against the development of early atherosclerosis.

Tubal ligation and risk of ovarian cancer in carriers of BRCA1 or BRCA2 mutations: a case-control study

BACKGROUND

In several case-control and prospective studies, tubal ligation has been associated with a decreased risk of invasive epithelial ovarian cancer. We aimed to assess the potential of tubal ligation in reducing the risk of ovarian cancer in women who carry predisposing mutations in the BRCA1 or BRCA2 genes.

METHODS

We did a matched case-control study among women from Canada, the USA, and the UK who had undergone genetic testing and who carried a pathogenic mutation in BRCA1 or BRCA2. Cases were 232 women with a history of invasive ovarian cancer, and controls were 232 women without ovarian cancer, and who had both ovaries intact. Cases and controls were matched for year of birth, country of residence, and mutation (BRCA1 or BRCA2). The odds ratio for developing ovarian cancer was estimated for tubal ligation, adjusting for oral contraceptive use, parity, history of breast cancer, and ethnic group.

FINDINGS

In an unadjusted analysis among BRCA1 carriers, significantly fewer cases than controls had ever had tubal ligation (30 of 173 [18%] vs 60 of 173 [35%], odds ratio 0.37 [95% CI 0.21-0.63]; p=0.0003). After adjustment for oral contraceptive use, parity, history of breast cancer and ethnic group, the odds ratio was 0.39 (p=0.002). Combination of tubal ligation and past use of an oral contraceptive was associated with an odds ratio of 0.28 (0.15-0.52). No protective effect of tubal ligation was seen among carriers of the BRCA2 mutation.

INTERPRETATION

Tubal ligation is a feasible option to reduce the risk of ovarian cancer in women with BRCA1 mutations who have completed childbearing.

Carbohydrate-carbohydrate binding of ganglioside to integrin alpha(5) modulates alpha(5)beta(1) function

Gangliosides GT1b and GD3, components of keratinocyte membranes, inhibit keratinocyte adhesion to fibronectin. Although ganglioside sialylation is known to be important, the mechanism of inhibition is unknown. Using purified insect recombinant alpha(5) and beta(1) proteins and alpha(5)beta(1) integrin from lysed keratinocyte-derived SCC12 cells, we have shown that GT1b and GD3 inhibit the binding of alpha(5)beta(1) to fibronectin. Co-immunoprecipitation of GT1b and alpha(5)beta(1) from SCC12 cells and direct binding of GT1b and GD3 to affinity-purified alpha(5)beta(1) from SCC12 cells and insect recombinant alpha(5)beta(1), particularly the alpha(5) subunit, further suggest interaction between ganglioside and alpha(5)beta(1). The carbohydrate moieties of integrin appear to be critical since gangliosides are unable to bind deglycosylated forms of alpha(5)beta(1) from SCC12 and insect cells or poorly glycosylated recombinant alpha(5)beta(1) from Escherichia coli cells. The GT1b-alpha(5)beta(1) interaction is inhibited by concanavalin A, suggesting that GT1b binds to mannose structures in alpha(5)beta(1). The preferential binding of GT1b to high mannose rather than reduced mannose ovalbumin further implicates the binding of GT1b to mannose structures. These data provide evidence that highly sialylated gangliosides regulate alpha(5)beta(1)-mediated adhesion of epithelial cells to fibronectin through carbohydrate-carbohydrate interactions between GT1b and the alpha(5) subunit of alpha(5)beta(1) integrin.

Dehydroepiandrosterone (DHEA) reduces neuronal injury in a rat model of global cerebral ischemia

INTRODUCTION

Many studies report an inverse correlation between levels of DHEA and neurological diseases. Exogenous DHEA protects hippocampal neurons against excitatory amino acid induced neurotoxicity. The purpose of this experiment is to evaluate the effect of DHEA in an animal model of transient but severe forebrain ischemia.

METHODS

At thirteen days prior to induction of ischemia, male Wistar rats were implanted with various doses of DHEA-placebo, 25 mg, 50 mg or 100 mg. Forebrain ischemia was induced for 10 min using a modified four-vessel occlusion technique, with hippocampal neuronal injury assessed at 7 days post-ischemically and expressed as a percentage of total cells.

RESULTS

Both normal and necrotic hippocampal CA(1) cells were counted. Percentages of hippocampal injury observed were 88+/-13% in animals treated with placebo, 84+/-8% in the 25 mg DHEA group, and 60+/-7% in the 50 mg DHEA group. Animals treated with 100 mg DHEA displayed a significant (P<0.05) reduction of hippocampal CA(1) cell injury at 60+/-7%

CONCLUSION

Treatment with a high dose, but not a low or moderate dose, of DHEA implantation reduces hippocampal CA(1) neuronal injury following severe but transient forebrain ischemia.

Ganglioside modulates ligand binding to the epidermal growth factor receptor

Whereas previous investigations have shown that pharmacologic addition of gangliosides inhibits keratinocyte proliferation by downregulating epidermal growth factor receptor phosphorylation, the underlying biochemical basis and physiologic relevance are unknown. Using Scatchard and displacement plots, we have shown that supplemental purified gangliosides decrease the binding of (125)I-labeled epidermal growth factor to keratinocyte-derived SCC12 cells. Conversely, SCC12 cells transfected with sialidase and thus depleted of gangliosides show increased ligand binding to the epidermal growth factor receptor, which is consistent with their increased proliferation in response to epidermal growth factor and transforming growth factor-alpha, and increased phosphorylation of the epidermal growth factor receptor, and downstream signal transduction pathway components. The mechanism of the altered binding appears to involve primarily decreased numbers of available receptors within the intact membrane, but not altered receptor protein expression. These studies provide evidence that the effect of gangliosides on keratinocyte proliferation results, at least in part, from the direct binding of ganglioside to the receptor and disruption of the receptor-ligand interaction. Manipulation of membrane ganglioside content may be a powerful new means to alter epidermal growth factor receptor-dependent cell proliferation.

Fetal neurosurgery

SURGERY BEFORE BIRTH has been performed for lethal conditions for several years. The techniques that have been developed are being applied to nonlethal conditions such as meningomyelocele. It is possible that fetal surgery might find a place in the management of certain forms of hydrocephalus as well. The challenge is to define which patients might benefit from such radical procedures before these techniques are accepted as standard care.

Light, Temperature, and Moisture Effects on Apothecium Production of Sclerotinia sclerotiorum

The purpose of this study was to quantify the effects of light, moisture, and temperature on apothecium production of Sclerotinia sclerotiorum. Sclerotia were placed in sand beds in crispers and exposed to two light intensities. For each light intensity, sclerotia were subjected to five temperature levels and three moisture levels. The results showed that the optimal temperature and temperature range for germination of sclerotia were affected by both light intensity and the moisture level of the sand. At light intensity of 80 to 90 mol m^-2 s^-1 (low light intensity treatment), the optimal temperatures were in the range of 12 to 18°C regardless of moisture level. At light intensity of 120 to 130 mol m^-2 s^-1 (high light intensity treatment), the optimal temperature was shifted to 20°C when the soil moisture level was high. Under high light intensity, only a few days were needed for initials to develop into apothecia. Under low light intensity, several weeks were needed for initials to develop into apothecia. The frequency with which initials developed into apothecia was high under high light intensity (80%) but low under low light intensity. The initials produced at low light intensity and high temperature (25 to 30°C) were thinner and longer. The apothecia also were smaller at low light intensity than those produced at high light intensity at any temperature. The periods for apothecium production were longer under lower temperature treatments. The relationship between apothecium production and degree days was analyzed. Apothecium production began at about 160 degree days and ceased at about 900 degree days at high light intensity. However, production began at about 760 degree days and ceased at 1,720 degree days at low light intensity. Nonlinear regression equations which describe the relationship between cumulative formation of apothecia and degree days were highly significant. The deviation between the observed value and the predicted value increased as degree days increased.