A Recurrent BRCA2 Mutation Explains the Majority of Hereditary Breast and Ovarian Cancer Syndrome Cases in Puerto Rico

Breast cancer is the most common cause of cancer diagnosis in women and is responsible for considerable mortality among the women of Puerto Rico. However, there are few studies in Puerto Rico on the genetic factors influencing risk. To determine the contribution of pathogenic mutations in BRCA1 and BRCA2, we sequenced these genes in 302 cases from two separate medical centers, who were not selected for age of onset or family history. We identified nine cases that are carriers of pathogenic germline mutation. This represents 2.9% of unselected cases and 5.6% of women meeting National Comprehensive Cancer Network (NCCN) criteria for BRCA testing. All of the identified pathogenic mutations were in the BRCA2 gene and the most common mutation is the p.Glu1308Ter (E1308X) mutation in BRCA2 found in eight out of nine cases, representing 89% of the pathogenic carriers. The E1308X mutation has been identified in breast and ovarian cancer families in Spain, and analysis of flanking DNA polymorphisms shows that all E1308X carriers occur on the same haplotype. This is consistent with BRCA2 E1308X being a founder mutation for the Puerto Rican population. These results will contribute to better inform genetic screening and counseling of breast and ovarian cancer cases in Puerto Rico and Puerto Rican populations in mainland United States.

The problem of misidentification between edible and poisonous wild plants: Reports from the Mediterranean area

Today, in many European countries, people are looking for wild edible plants to experience new tastes and flavors, by following the new trend of being green and environmentally friendly. Young borage and spinach leaves can be easily confused by inexpert pickers with those of other plants, including poisonous ones, such as Mandragora autumnalis Bertol. (mandrake) or Digitalis purpurea L. (foxglove), common in southern and northern Italy respectively. In the last twenty years, several cases of intoxication by accidental ingestion of mandrake and foxglove have been reported. The purpose of this work was to perform a pharmacognostic characterization of young leaves from borage, mandrake, foxglove and spinach, by micro-morphological, molecular and phytochemical techniques. The results showed that each of the three techniques investigated could be sufficient alone to provide useful information for the identification of poisonous species helping the medical staff to manage quickly the poisoned patients. However, the multi-disciplinary approach proposed could be very useful to asses the presence of poisonous plants in complex matrices, to build a database containing morphological, molecular and phytochemical data for the identification of poisonous species or in forensic toxicology, given their increasingly frequent use due to their low cost and relatively common availability.

Epiglottic Non-Hodgkin's Lymphoma: Case Report

A locally recurrent head and neck nodal, B cell nodular, non-Hodgkin's lymphoma transformed to a diffuse histologic pattern with a peculiar bone marrow and epiglottic involvement without other apparent localizations is reported. Radiotherapy proved highly effective for local control of the epiglottic lesion but chemotherapy failed to eradicate bone marrow disease.

Differential Effects of EGFL6 on Tumor versus Wound Angiogenesis

Angiogenesis inhibitors are important for cancer therapy, but clinically approved anti-angiogenic agents have shown only modest efficacy and can compromise wound healing. This necessitates the development of novel anti-angiogenesis therapies. Here, we show significantly increased EGFL6 expression in tumor versus wound or normal endothelial cells. Using a series of in vitro and in vivo studies with orthotopic and genetically engineered mouse models, we demonstrate the mechanisms by which EGFL6 stimulates tumor angiogenesis. In contrast to its antagonistic effects on tumor angiogenesis, EGFL6 blockage did not affect normal wound healing. These findings have significant implications for development of anti-angiogenesis therapies.

A preliminary longitudinal study on the cognitive and functional outcome of bipolar excellent lithium responders

BACKGROUND

Neurocognitive dysfunction in bipolar disorder represents a possible marker of underlying pathophysiology, but to date, most studies are cross-sectional and heterogeneous with regard to pharmacological treatments. In the present study we investigated the 6-year cognitive and functional outcome of a sample of euthymic excellent lithium responders (ELR).

METHOD

A total sample of twenty subjects was assessed at baseline and 6years later: ten diagnosed of bipolar disorder according to DSM-IV criteria and ten healthy matched controls. The sample size was enough to find statistical differences between groups, with a statistical power of 0.8. Bipolar patients were on lithium treatment during all this follow-up period and fulfilled ELR criteria as measured by the Alda scale. A neuropsychological test battery tapping into the main cognitive domains was used at baseline and at after 6-year of follow-up. Functional outcome was evaluated by means of the Functioning Assessment Short Test at study endpoint.

RESULTS

Repeated measures multivariate analyses of variance showed that bipolar patients were cognitively impaired in the executive functioning, inhibition, processing speed and verbal memory domains (p<0.03) compared to controls and such deficits were stable over time. Longer duration of illness and lower psychosocial outcome were significantly related to cognitive impairment (p<0.05).

CONCLUSIONS

Cognitive dysfunction was present even in euthymic ELR. These deficits remain stable over the long term, and are basically associated with greater symptoms and poorer psychosocial adjustment.

Uncovering Hospitalists' Information Needs from Outside Healthcare Facilities in the Context of Health Information Exchange Using Association Rule Learning

BACKGROUND

Important barriers to health information exchange (HIE) adoption are clinical workflow disruptions and troubles with the system interface. Prior research suggests that HIE interfaces providing faster access to useful information may stimulate use and reduce barriers for adoption; however, little is known about informational needs of hospitalists.

OBJECTIVE

To study the association between patient health problems and the type of information requested from outside healthcare providers by hospitalists of a tertiary care hospital.

METHODS

We searched operational data associated with fax-based exchange of patient information (previous HIE implementation) between hospitalists of an internal medicine department in a large urban tertiary care hospital in Florida, and any other affiliated and unaffiliated healthcare provider. All hospitalizations from October 2011 to March 2014 were included in the search. Strong association rules between health problems and types of information requested during each hospitalization were discovered using Apriori algorithm, which were then validated by a team of hospitalists of the same department.

RESULTS

Only 13.7% (2 089 out of 15 230) of the hospitalizations generated at least one request of patient information to other providers. The transactional data showed 20 strong association rules between specific health problems and types of information exist. Among the 20 rules, for example, abdominal pain, chest pain, and anaemia patients are highly likely to have medical records and outside imaging results requested. Other health conditions, prone to have records requested, were lower urinary tract infection and back pain patients.

CONCLUSIONS

The presented list of strong co-occurrence of health problems and types of information requested by hospitalists from outside healthcare providers not only informs the implementation and design of HIE, but also helps to target future research on the impact of having access to outside information for specific patient cohorts. Our data-driven approach helps to reduce the typical biases of qualitative research.

Abstract 1952: Adverse effects of erythropoietin stimulates tumor growth via EphB4

Abstract: While recombinant human erythropoietin (rhEpo) has been widely used to treat anemia in cancer patients, concerns about its adverse effects on patient survival have emerged. However the lack of correlation between expression of the canonical EpoR and rhEpo's effects on cancer cells prompted us to consider the existence of an alternative Epo receptor. Methods: We analyzed the membrane-bound portion of the proteome for candidate receptors possessing structural, regulatory, and functional features consistent with Epo binding and tumorigenic signaling. To examine the potential for EphB4 binding to Epo, we generated EpoR−/- MEFs from EpoR−/- mice. We injected A2780-shControl and-shEpoR cells, shEphB4 or -shEpoR/shEphB4 cells in nude mice to study rhEpo induced tumor progression. We also assessed potential effects of tumoral EpoR or EphB4 expression on the effects of ESA treatment in patients with ovarian (N = 175) or breast (N = 88) cancer. Results: Through systems-based approaches we identified EphB4 as an alternate Epo receptor. MST experiments with fluorophore labeled rhEpo demonstrated binding to EpoR with an apparent dissociation constant (KD,app) of 28.0 ± 14.0 nM and EphB4 with a KD,app value of 880.6 ± 128.6 nM. EphB4 and EphrinB2 bound with a KD,app value of 140.5 ± 28.3 nM. We showed that [I125]rhEpo can bind to these cells EpoR−/- MEFs cells.

EphB4 triggered the downstream signaling via STAT3 and promoted rhEpo-induced tumor growth and progression. rhEpo stimulated in vivo growth of A2780-shControl (p&lt;0.01) and-shEpoR cells (p&lt;0.01), but not -shEphB4 or -shEpoR/shEphB4 cells. In human ovarian and breast cancer samples, expression of EphB4 rather than the canonical EpoR correlated with decreased disease-specific survival in rhEpo-treated patients. Conclusion: These results identify EphB4 as a critical mediator of erythropoietin-induced tumor progression in cancer patients and further provide a novel and clinically significant dimension to the biology of erythropoietin.

Citation Format: Sunila Pradeep, Jie Huang, Edna Mora, Alpa Nick, Minsoon Cho, Sherry Wu, Rajesha Rupaimoole, Chiyi Xiong, Chun Li, Gabriel Lopez-Berestein, David Jackson, Anil Sood. Adverse effects of erythropoietin stimulates tumor growth via EphB4. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1952. doi:10.1158/1538-7445.AM2015-1952

Proceedings of the 1st Puerto Rico Biobanking Workshop

The 1st Puerto Rico Biobanking Workshop took place on August 20st, 2014 in the Auditorium of the Comprehensive Cancer Center of the University of Puerto Rico, Medical Sciences Campus in San Juan Puerto Rico. The program for this 1-day, live workshop included lectures by three biobanking experts, followed by presentations from existing biobanks in Puerto Rico and audience discussion. The need for increasing biobanking expertise in Puerto Rico stems from the fact that Hispanics in general are underrepresented in the biobanks in existence in the US, which limits the research conducted specifically to understand the molecular differences in cancer cells compared to other better studied populations. In turn, this lack of information impairs the development of better diagnostic and therapeutic approaches for our population. Dr. James Robb, M.D., F.C.A.P., consulting pathologist to the National Cancer Institute (NCI) and the Office of Biorepositories and Biospecimen Research (OBBR), opened the workshop with a discussion on the basic aspects of the science of biobanking (e.g., what is a biobank; its goals and objectives; protocols and procedures) in his talk addressing the importance of banking tissues for advancing biomedical research. Next, Dr. Gustavo Stefanoff, from the Cancer Institutes Network of Latin America (RINC by its name in Spanish), explained the mission, objectives, and structure of the Network of Latin-American and Caribbean Biobanks (REBLAC by its name in Spanish), which despite limited resources and many challenges, currently accrue high quality human tissue specimens and data to support cancer research in the region. Dr. Robert Hunter-Mellado, Professor of Internal Medicine, Universidad Central del Caribe, followed with an examination of the ethical and regulatory aspects of biobanking tissues for future research, including informed consent of subjects; protection of human subjects rights; and balancing risks and benefit ratios. In the afternoon, the directors of existing biobanks in Puerto Rico (the Puerto Rico Biobank, the Comprehensive Cancer Center biobank, and an HIV-focused biobank at Universidad Central del Caribe) presented their experiences and challenges with establishing biobanks for research in Puerto Rico. In sum, this workshop presented opportunities to share knowledge in the science of biobanking, for further training, and of networking among the participants (34 from 4 different institutions), which will strengthen the collaborative links between investigators studying cancer in Latin America, the Caribbean, and the US.

Persistence of cognitive impairment and its negative impact on psychosocial functioning in lithium-treated, euthymic bipolar patients: a 6-year follow-up study

BACKGROUND

Previous cross-sectional studies report that cognitive impairment is associated with poor psychosocial functioning in euthymic bipolar patients. There is a lack of long-term studies to determine the course of cognitive impairment and its impact on functional outcome. Method A total of 54 subjects were assessed at baseline and 6 years later; 28 had DSM-IV TR bipolar I or II disorder (recruited, at baseline, from a Lithium Clinic Program) and 26 were healthy matched controls. They were all assessed with a cognitive battery tapping into the main cognitive domains (executive function, attention, processing speed, verbal memory and visual memory) twice over a 6-year follow-up period. All patients were euthymic (Hamilton Rating Scale for Depression score lower than 8 and Young mania rating scale score lower than 6) for at least 3 months before both evaluations. At the end of follow-up, psychosocial functioning was also evaluated by means of the Functioning Assessment Short Test.

RESULTS

Repeated-measures multivariate analysis of covariance showed that there were main effects of group in the executive domain, in the inhibition domain, in the processing speed domain, and in the verbal memory domain (p<0.04). Among the clinical factors, only longer illness duration was significantly related to slow processing (p=0.01), whereas strong relationships were observed between impoverished cognition along time and poorer psychosocial functioning (p<0.05).

CONCLUSIONS

Executive functioning, inhibition, processing speed and verbal memory were impaired in euthymic bipolar out-patients. Although cognitive deficits remained stable on average throughout the follow-up, they had enduring negative effects on psychosocial adaptation of patients.

Breast cancer molecular subtypes and survival in a hospital-based sample in Puerto Rico

Information on the impact of hormone receptor status subtypes in breast cancer (BC) prognosis is still limited for Hispanics. We aimed to evaluate the association of BC molecular subtypes and other clinical factors with survival in a hospital-based female population of BC cases in Puerto Rico. We analyzed 663 cases of invasive BC diagnosed between 2002 and 2005. Information on HER-2/neu (HER-2) overexpression, estrogen (ER), and progesterone (PR) receptor status and clinical characteristics were retrieved from hospitals cancer registries and record review. Survival probabilities by covariates of interest were described using the Kaplan–Meier estimators. Cox proportional hazards models were employed to assess factors associated with risk of BC death. Overall, 17.3% of BC cases were triple-negative (TN), 61.8% were Luminal-A, 13.3% were Luminal-B, and 7.5% were HER-2 overexpressed. In the multivariate Cox model, among patients with localized stage, women with TN BC had higher risk of death (adjusted hazard ratio [HR]: 2.57, 95% confidence interval [CI]: 1.29–5.12) as compared to those with Luminal-A status, after adjusting for age at diagnosis. In addition, among women with regional/distant stage at diagnosis, those with TN BC (HR: 5.48, 95% CI: 2.63–11.47) and those HER-2+, including HER-2 overexpressed and Luminal-B, (HR: 2.73, 95% CI:1.30–5.75) had a higher mortality. This is the most comprehensive epidemiological study to date on the impact of hormone receptor expression subtypes in BC survival in Puerto Rico. Consistent to results in other populations, the TN subtype and HER-2+ tumors were associated with decreased survival.

Synthesis, Stability, Cellular Uptake, and Blood Circulation Time of Carboxymethyl-Inulin Coated Magnetic Nanoparticles

Iron oxide nanoparticles were coated with the biocompatible, biodegradable, non-immunogenic polysaccharide inulin by introduction of carboxyl groups into the inulin structure and conjugation with amine groups on the surface of iron oxide nanoparticles grafted with 3-aminopropyltriethoxysilane. The resulting nanoparticles were characterized by FT-IR spectroscopy, transmission electron microscopy, dynamic light scattering, zeta potential, SQUID magnetometry, and with respect to their energy dissipation rate in applied alternating magnetic fields. The nanoparticles had a hydrodynamic diameter in the range of 70 ± 10 nm and were superparamagnetic, with energy dissipation rates in the range of 58-175 W/g for an applied field frequency of 233 kHz and an applied field amplitude in the range of 20-48 kA/m. The nanoparticles were stable in a range of pH, at temperatures between 23°C and 53°C, and in short term storage in water, PBS, and culture media. The particles were non-cytotoxic to the immortalized human cancer cell lines Hey A8 FDR, A2780, MDA 468, MCF-7 and Caco-2. The nanoparticles were readily taken up by Caco-2 cells in a time and concentration dependent fashion, and were found to have a pharmacokinetic time constant of 47 ± 3 min. The small size, non-cytotoxicity, and efficient energy dissipation of the particles could make them useful for biomedical applications such as magnetic fluid hyperthermia.

Biological roles of the Delta family Notch ligand Dll4 in tumor and endothelial cells in ovarian cancer

Emerging evidence suggests that the Notch/Delta-like ligand 4 (Dll4) pathway may offer important new targets for antiangiogenesis approaches. In this study, we investigated the clinical and biological significance of Dll4 in ovarian cancer. Dll4 was overexpressed in 72% of tumors examined in which it was an independent predictor of poor survival. Patients with tumors responding to anti-VEGF therapy had lower levels of Dll4 than patients with stable or progressive disease. Under hypoxic conditions, VEGF increased Dll4 expression in the tumor vasculature. Immobilized Dll4 also downregulated VEGFR2 expression in endothelial cells directly through methylation of the VEGFR2 promoter. RNAi-mediated silencing of Dll4 in ovarian tumor cells and tumor-associated endothelial cells inhibited cell growth and angiogenesis, accompanied by induction of hypoxia in the tumor microenvironment. Combining Dll4-targeted siRNA with bevacizumab resulted in greater inhibition of tumor growth, compared with control or treatment with bevacizumab alone. Together, our findings establish that Dll4 plays a functionally important role in both the tumor and endothelial compartments of ovarian cancer and that targeting Dll4 in combination with anti-VEGF treatment might improve outcomes of ovarian cancer treatment.

Abstract 4457: In Search of a novel EPO receptor: The clinical significance of the Eph connection

Background: Treatment of chemotherapy-induced anemia with recombinant human erythropoietin (Epo) has been shown to reduce transfusion requirements and improve quality of life among patients with solid malignancies. Recent reports of negative outcomes among cancer patients receiving Epo raises the concern that Epo may promote tumor growth. Given the uncertain relevance of the erythropoietin receptor (EpoR) in mediating the tumor growth stimulatory effects of Epo, we identified Ephrin B4 (EphB4) as a novel alternate receptor for Epo. The current work tests if the clinical impact of Epo administration on prognosis was receptor-dependent in patients with epithelial ovarian cancer.

Methods: Immunohistochemistry was used to characterize receptor expression in 175 invasive epithelial ovarian cancers. An H-score characterizing EpoR and EphB4 expression was calculated for each clinical sample. Slides were scored by a gynecologic pathologist blinded to the clinical outcome. Clinical data was extracted and 5 year disease specific survival was calculated and correlated with degree of receptor expression as well as Epo administration.

Results: The mean age of patients was 58.2 (range 20-92). Eighty-five percent of patients had serous histology and 91% had high grade tumors. Ninety-six percent of patients had stage II-IV disease and 67% underwent optimal cytoreduction (defined as &lt;1cm residual disease). EpoR overexpression was noted in 79% of tumors and EphB4 overexpression was seen in 39%. Multivariate analysis revealed EphB4, but not EpoR overexpression to be an independent predictor of poor survival (HR 4.53 [95% CI 2.87-7.16], p&lt;0.001 vs. HR 1.21 [95% CI 0.72-2.02], p=0.47). Kaplan-Meier analyses indicate that high EphB4 was related to high mortality rate (3 years vs. 6.69 years, p&lt;0.0001), but EpoR overexpression was not (4.78 years vs. 5.88 years, p=0.64). Additionally, Epo treatment was related to higher mortality among patients with EphB4 overexpressing tumors (2.18 years vs. 4.52 years, p=0.0004), but not patients with high tumoral levels of EpoR (4.38 years vs. 5.28 years, p=0.19).

Conclusions: We identify EphB4 as a novel Epo receptor. Tumor overexpression of EphB4, and not EpoR, is associated with poor survival among patients with epithelial ovarian cancer. Epo treatment among patients with EphB4 overexpressing tumors results in decreased disease-specific patient survival.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4457. doi:10.1158/1538-7445.AM2011-4457

The DNA repair complex Ku70/86 modulates Apaf1 expression upon DNA damage

Apaf1 is a key regulator of the mitochondrial intrinsic pathway of apoptosis, as it activates executioner caspases by forming the apoptotic machinery apoptosome. Its genetic regulation and its post-translational modification are crucial under the various conditions where apoptosis occurs. Here we describe Ku70/86, a mediator of non-homologous end-joining pathway of DNA repair, as a novel regulator of Apaf1 transcription. Through analysing different Apaf1 promoter mutants, we identified an element repressing the Apaf1 promoter. We demonstrated that Ku70/86 is a nuclear factor able to bind this repressing element and downregulating Apaf1 transcription. We also found that Ku70/86 interaction with Apaf1 promoter is dynamically modulated upon DNA damage. The effect of this binding is a downregulation of Apaf1 expression immediately following the damage to DNA; conversely, we observed Apaf1 upregulation and apoptosis activation when Ku70/86 unleashes the Apaf1-repressing element. Therefore, besides regulating DNA repair, our results suggest that Ku70/86 binds to the Apaf1 promoter and represses its activity. This may help to inhibit the apoptosome pathway of cell death and contribute to regulate cell survival.

[Occupational health practice among law, evidence and ethics: a field study]

BACKGROUND

Quality in health care is defined as the degree to which health services increase the likelihood of desired health outcomes and are consistent with the law, the evidence and the ethical values.

MATERIALS AND METHODS

The paper aims at providing a framework in which the concept of quality is applied in the field of occupational health by analysing real-life decisions.

RESULTS

The Italian law states that the practice must be evidence-based and respectful of the code of ethics, emphasizeing that the practice should be relevant, knowledge-based, sound and appropriate. Any dilemma should be dealt according to the ethical principles of beneficience, autonomy and justice. Both the law and the code require that the practice is based on the available evidence. Results show that decisions in selected cases can be made according the above mentioned criteria. CONCLUSION; Decisions made on the basis of a process founded on scientific evidence result in effective and high-quality outcomes respectful of both law and ethics.

Abstract B57: Breast cancer subtypes and survival in a hospital-based sample in Puerto Rico

Introduction: Breast cancer is the most common female malignancy in Puerto Rico and the United States. Breast cancer is a multifaceted disease comprised of distinct biological subtypes with diverse etiology, therapeutic indications and clinical outcomes. Information on the impact of hormone receptor status sub-types in disease prognosis is still limited for Hispanics. To overcome this limitation, we aimed to evaluate the association of breast cancer subtypes and other clinical factors with breast cancer survival in a hospital-based female population of breast cancer cases.

Methods: We analyzed data from female patients with invasive breast cancer diagnosed between 2000-2005, at the I. Gonzalez Martinez Hospital and the Auxilio Mutuo Hospital (n=974). Information on Her2/neu (Her2) overexpression, Estrogen receptor (ER) and Progesterone receptor (PR) status and other clinical characteristics was retrieved from the hospitals’ cancer registries, the Puerto Rico Central Cancer Registry and from medical and pathology record review. Survival by covariates of interest was estimated using the Kaplan-Meier method, and survival curves were compared using the Wilcoxon test. Multivariate Cox proportional hazards models were employed to assess factors associated to breast cancer survival.

Results: Overall, 22.5% of breast cancer cases were Her2+, 16.6% were triple negative (ER-/PR-/Her2-) and 60.9% were Her2-/ER+ or PR+. Factors associated to breast cancer death in bivariate analyses included younger age at diagnosis (&lt; 50 years) (HR=1.70, 95% CI: 1.17-2.49), ER- (HR=1.91, 95% CI: 1.38-2.64), PR- (HR=1.10, 95% CI: 1.51 −2.07) and triple negative status (HR=2.45, 95% CI: 1.72-3.48); no differences were observed by Her2 status (p&gt;0.05). Meanwhile, women with regional (HR=1.83, 95% CI: 1.29-2.61) and distant (HR=9.21, 95% CI:4.94-17.17) disease at time of diagnosis had higher risk of death as compared to those with localized disease. In multivariate analysis, Her2 positivity was still not associated with breast cancer mortality after adjusting for age and stage at diagnosis (HR=1.22, 95% CI:0.83-1.78). Meanwhile, women with triple-negative breast cancer had higher risk of breast cancer death after adjusting for age and stage at diagnosis (HR=2.65, 95% CI:1.80-3.88).

Conclusions: This is the most comprehensive epidemiological study to date on the impact of hormone receptor expression sub-types in breast cancer survival in Puerto Rico. The clinical correlates of breast cancer survival in this population follow the same trends described previously in US populations. Even though no significant differences in survival were observed by Her2 overexpression status, consistent to results in other populations, the triple negative subtype was associated with decreased survival. The results of this study are useful for the development of breast cancer control strategies in Puerto Rico.

Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):B57.

Clinicopathological factors associated to HER-2 status in a hospital-based sample of breast cancer patients in Puerto Rico

Breast cancer is the most common female malignancy in Puerto Rico. Cases with human epidermal growth factor receptor 2 (HER-2) oncoprotein overamplification are associated with aggressive clinical behavior. Given the limited availability of information for Puerto Rico, we aimed to evaluate the prevalence and clinical correlates of HER-2 gene overexpression among a hospital-based female population of breast cancer cases. We analyzed data from 1,049 female patients with invasive breast cancer (diagnosed 2000-2005) at the I. González Martínez Oncologic Hospital and the Auxilio Mutuo Hospital. HER-2 status and other clinical characteristics were retrieved from the hospitals' cancer registries, from the Puerto Rico Central Cancer Registry, and from a review of medical and pathological records. Prevalence odds ratios were estimated with 95% confidence intervals, using logistic regression models to quantify the association between HER-2 status and different clinicophatological factors. The overall prevalence of positive HER-2 expression was 22.5%. In the multivariate logistic regression model, factors significantly associated with HER-2 positivity included a diagnosis age of < 50 years, having a tumor with negative progesterone receptor (PR) status, and having regional disease (p < 0.05). No significant differences in HER-2 positivity were observed by tumor histology or estrogen receptor (ER) status (p > 0.05). This is the most comprehensive epidemiological study to date on HER-2 status in Puerto Rico. The prevalence and correlates of HER-2 overexpression in this study are comparable to those observed in US populations. Study results will aid in the development of breast cancer control strategies in Puerto Rico.

Regulation of tumor angiogenesis by EZH2

Although VEGF-targeted therapies are showing promise, new angiogenesis targets are needed to make additional gains. Here, we show that increased Zeste homolog 2 (EZH2) expression in either tumor cells or in tumor vasculature is predictive of poor clinical outcome. The increase in endothelial EZH2 is a direct result of VEGF stimulation by a paracrine circuit that promotes angiogenesis by methylating and silencing vasohibin1 (vash1). Ezh2 silencing in the tumor-associated endothelial cells inhibited angiogenesis mediated by reactivation of VASH1, and reduced ovarian cancer growth, which is further enhanced in combination with ezh2 silencing in tumor cells. Collectively, these data support the potential for targeting ezh2 as an important therapeutic approach.

Sustained small interfering RNA delivery by mesoporous silicon particles

RNA interference (RNAi) is a powerful approach for silencing genes associated with a variety of pathologic conditions; however, in vivo RNAi delivery has remained a major challenge due to lack of safe, efficient, and sustained systemic delivery. Here, we report on a novel approach to overcome these limitations using a multistage vector composed of mesoporous silicon particles (stage 1 microparticles, S1MP) loaded with neutral nanoliposomes (dioleoyl phosphatidylcholine, DOPC) containing small interfering RNA (siRNA) targeted against the EphA2 oncoprotein, which is overexpressed in most cancers, including ovarian. Our delivery methods resulted in sustained EphA2 gene silencing for at least 3 weeks in two independent orthotopic mouse models of ovarian cancer following a single i.v. administration of S1MP loaded with EphA2-siRNA-DOPC. Furthermore, a single administration of S1MP loaded with-EphA2-siRNA-DOPC substantially reduced tumor burden, angiogenesis, and cell proliferation compared with a noncoding control siRNA alone (SKOV3ip1, 54%; HeyA8, 57%), with no significant changes in serum chemistries or in proinflammatory cytokines. In summary, we have provided the first in vivo therapeutic validation of a novel, multistage siRNA delivery system for sustained gene silencing with broad applicability to pathologies beyond ovarian neoplasms.

Abstract 1793: Platelet-derived growth factor receptor alpha blockade significantly enhances sensitization to docetaxel in ovarian carcinoma

Objective: Platelet-derived growth factor receptor alpha (PDGFRα) is a member of class III receptor tyrosine kinase and is associated with cell survival. Here, we examined whether PDGFRα blockade enhances the anti-tumor activity of taxanes in ovarian carcinoma.

Methods: PDGFRα expression was evaluated with RT-PCR and Western blot in multiple ovarian cancer cell lines. Human-specific monoclonal antibody to PDGFRα (IMC-3G3, ImClone Systems, NJ, USA) was used for in-vitro (cell viability assay, apoptosis assay) and in-vivo experiments with or without docetaxel.

Results: All eleven tested ovarian cancer cell lines had variable expression of PDGFRα. OVCA433 cell line had the highest level of expression of PDGFRα. IMC-3G3 blocked PDGFRα phosphorylation in response to PDGF-AA stimulation. IMC-3G3 alone had no affect on cell viability in all tested cell lines. However, IMC-3G3 significantly enhanced sensitization to docetaxel: IC50 reduction rate, SKOV3-ip1, 25.5%; HeyA8-parental, 31.7%; OVCA433, 35.3%; and HeyA8-MDR, 44.2% (all, p&lt;0.05). While treatment with IMC-3G3 alone did not increase apoptosis, concurrent use with docetaxel significantly enhanced docetaxel-mediated apoptosis (mean percentage of total apoptotic cells in SKOV3-ip1, untreated vs IMC-3G3 alone vs docetaxel alone vs docetaxel with IMC-3G3, 7.3% vs 7.1% vs 15.4% vs 22.2%, p&lt;0.001). In the in-vivo experiment with SKOV3-ip1 bearing mice, administration of IMC-3G3 monotherapy had no significant anti-tumor effects compared to the control group (mean tumor weight, 2.5 ± 0.32 vs 2.9 ± 0.51 grams, p&gt;0.05). Concurrent use of IMC-3G3 with docetaxel significantly reduced tumor weight compared to docetaxel alone (mean tumor weight, 0.22 ± 0.07 vs 0.63 ± 0.14 grams, tumor reduction rate 65.1%, p&lt;0.05).

Conclusion: IMC-3G3 significantly enhances the anti-tumor effects of docetaxel. Therefore, targeting PDGFRα may be an attractive approach for increasing the cytotoxic effects of chemotherapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1793.

Abstract 873: Prevalence and correlates of HER2/neu overexpression among invasive breast cancer cases in two hospitals in Puerto Rico

Introduction Breast cancer (BC) is the most common female malignancy in Puerto Rico. Cases with human epidermal growth factor receptor 2 (HER-2)/neu oncoprotein overamplification are consistently associated with poor prognosis, poor response to endocrine treatment, and an increased likelihood of recurrence. The objective is to evaluate the prevalence of HER2 /neu gene overexpression among a hospital-based female population of BC cases in Puerto Rico, and to determine its association with other clinical characteristics. Methods This cross-sectional study analyzed data from female patients with invasive BC diagnosed between 2000 and 2005, at the I. Gonzalez Martinez Hospital and the Auxilio Mutuo Hospital (n=1,082) in San Juan, Puerto Rico. Information on Her-2 status and other clinical characteristics was retrieved form the hospital's cancer registries and from medical record review. This study was approved by the Institutional Review Boards of the participating hospitals. Logistic regression models were used to evaluate the associations between relevant clinical characteristics and Her-2 status. Results: The prevalence of Her-2/neu overexpression in our study aas 20.9%, whereas 72.3% of the cases were ER positive and 59.3% were PR positive. In multivariate analysis, women with an age at diagnosis ≤ 50 years were 1.74 (95% CI=1.26-2.41) times more likely to be Her-2 positive as compared with those with an age at diagnosis ≥ 50 years. Regarding ER/PR status, women with ER+/PR- and those with ER+/PR+ were 1.97 (95% CI=1.30-2.98) and 2.15 (95% CI=1.49-3.10) times more likely to be Her-2 positive as compared to those with ER-/PR- status. Finally, women with invasive ductal histology were 1.79 (95% CI=1.08-2.95) more likely to be Her-2 positive as compared to those with invasive lobular histology. Women with tumor grade III/IV, tumor size ≥ 2 cm and lymph node metastasis were also more likely to be Her-2 positive (p&lt;0.05). Conclusions: The prevalence of Her-2/neu overexpression in this population of Puerto Rican patients (20.9) and its association with earlier age at diagnosis, tumor size, lymph node metastasis and other clinical characteristics shows that BC patients with Her-2 positive tumors followed similar profiles as Her-2 positive BC patients in the US population. Results from this study will be useful for the development of future BC prevention and control strategies in Puerto Rico.

Sponsors: This work was supported by an unrestricted grant from Glaxo SmithKline with additional support from the National Institutes of Health and National Center for Research Resources (NCRR) [grant number G12RR03051 and U54CA96297].

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 873.

Reduced carbon solubility in Fe nanoclusters and implications for the growth of single-walled carbon nanotubes

Fe nanoclusters are becoming the standard catalysts for growing single-walled carbon nanotubes via chemical vapor decomposition. Contrary to the Gibbs-Thompson model, we find that the reduction of the catalyst size requires an increase of the minimum temperature necessary for the growth. We address this phenomenon in terms of solubility of C in Fe nanoclusters and, by using first-principles calculations, we devise a simple model to predict the behavior of the phases competing for stability in Fe-C nanoclusters at low temperature. We show that, as a function of particle size, there are three scenarios compatible with steady state growth, limited growth, and no growth of single-walled carbon nanotubes, corresponding to unaffected, reduced, and no solubility of C in the particles.

[Glucan solution nasal spray vs saline in the treatment of chronic rhinosinusitis: a multi-centric double blind randomised clinical trial]

OBJECTIVES

The aim of our study was to evaluate the efficacy of 30 days treatment with glucan solution nasal spray vs. saline in the treatment of signs and symptoms of chronic rhinosinusitis.

MATERIALS AND METHODS

100 patients affected by chronic rhinosinusitis were enrolled. At the beginning and at the end of the study were evaluated: nasal congestion, headache, rhinorrea, facial pain, rhinopharyngeal exudate, inferior turbinate hypertrophy; a complete instrumental analysis of nasal functions by Active Anterior Rhinomanometry, nasal Muco-Ciliary Transport time and scraping of nasal mucosa was also performed. The patients were randomized 1:1 for receiving intranasal saline or intranasal glucan solution spray. Treatment was administered as follows: 2 puffs/nostril 3 times a day for 30 days.

RESULTS

The patients in therapy with the glucan solution showed a significant improvement concerning rhinorrea facial pain, intensity of headache, inferior turbinate hypertrophy, rhinopharyngeal exudates, inspiratory/expiratory nasal resistences, Muco-ciliary transport time, normalization of nasal mucosas and rhinocytogram; saline lavage didn't show this effects. Both treatment improved rhinorrea, instead both treatment didn't affect nasal congestion.

CONCLUSIONS

According to the results of our multicentric double blind randomized study, we suggest the use of glucan solution nasal spray as an efficacious therapeutic tool in the management of nasal symptoms in patients affected by chronic rhinosinusitis.

Chemical activation of carbon mesophase pitches

This paper studies the chemical activation of mesophase pitches of different origins in order to obtain activated carbons suitable for use as electrodes in supercapacitors. The effect that the activating agent (NaOH, LiOH, and KOH), the alkaline hydroxide/pitch ratio, and the activation temperature had on the characteristics of the resultant activated carbons was studied. LiOH was found to be a noneffective activating agent, while activation with NaOH and KOH yielded activated carbons with high apparent surface areas and pore volumes. The increase of the KOH/pitch ratio caused an increase of the chemical attack on the carbon, producing higher burnoffs and development of porosity. Extremely high apparent surface areas were obtained when the petroleum pitch was activated with 5:1 KOH/carbon ratio. The increase of the activation temperature caused an increase of the burnoff, although the differences were not as significant as those derived from the use of different proportions of activating agent.

A double-blind randomized placebo-controlled trial with short-term beta-glucuronidase therapy in children with chronic rhinoconjunctivitis and/or asthma due to dust mite allergy

BACKGROUND

Enzyme potentiated desensitization, in which beta-glucuronidase (BG) is administered with low doses of mixed allergens, was proposed in the 1970s for specific immunotherapy. The BG currently commercially available in a purified and standardized preparation devoid of any allergen has been suggested as a regulator in the allergic immune response, acting on the cytokine-network of type 2 helper T cells. A double-blind trial with a single-dose of BG proved effective in preventing symptoms in adult patients with rhinoconjunctivitis due to grass pollens.

OBJECTIVE

The aim of this randomized double-blind placebo-controlled trial was to confirm the safety and effectiveness of double-dose intradermal BG immunotherapy in preventing symptoms in children suffering from chronic rhinoconjunctivitis and/or asthma due to dust mite.

METHOD

We randomized 125 children with dust-mite related chronic rhinoconjunctivitis and/or asthma to the BG treated group (67) or the placebo group (58). All patients were screened before treatment (TO), at BG or placebo administration (T1 and T3), and at 3 and 9 months after T1 (T2 and T4). Drug intake and bronchial, nasal and ocular symptoms were recorded in a diary.

RESULTS

Patients in both groups completed the study and BG treatment was well tolerated without side effects. Significant differences in symptoms were observed, in particular for conjunctivitis (P= .008). The total drug intake for allergic symptoms was significantly lower in the treated group than in the placebo group (P<. 01).

CONCLUSIONS

BG immunotherapy is efficacious, safe, and well tolerated in allergic children. Moreover, good compliance with the administration of 2 doses per year and the lack of significant side effects makes the benefit/risk ratio of this treatment particularly favorable.

N-(4-Hydroxyphenyl)retinamide and nitric oxide pro-drugs exhibit apoptotic and anti-invasive effects against bone metastatic breast cancer cells

Breast cancer most frequently metastasizes to bone causing decreased quality of life and morbidity. Since current treatments are palliative, strategies to prevent bone metastases in breast cancer patients are required. There is substantial evidence indicating that high levels of nitric oxide (NO) suppress tumor growth and metastasis in vivo. We hypothesize that agents that produce high concentrations of NO could prevent the spread of breast cancer to bone. We previously demonstrated that the synthetic retinoid N-(4-hydroxyphenyl)retinamide (4-HPR) produces high levels of NO via the induction of NO synthases. NO pro-drugs are designed to produce large amounts of NO without inducing NO synthases but upon metabolism by their intracellular targets. The objective of this study was to determine the effectiveness of 4-HPR and an NO pro-drug, diethylamineNONOate/AM (NONO-AM), in inhibiting the growth and invasiveness of bone metastatic breast cancer cells. Parental MDA-MB-231 breast cancer cells were resistant to 4-HPR-induced apoptosis at clinically relevant doses, whereas 4-HPR-induced apoptosis in a dose-dependent manner in MDA-MB-231/F10 bone metastatic breast cancer cells. Unlike 4-HPR, NONO-AM induced apoptosis in a dose-dependent manner in both parental MDA-MB-231 cells and F10 cells. The bone metastatic F10 cells were more sensitive to the anti-invasive effects of 4-HPR and NONO-AM than were MDA-MB-231 cells. Although suppression of matrix metalloprotease-9 activity may be one mechanism by which 4-HPR decreases the invasion of F10 cells, it does not appear to be the anti-invasion mechanism of NONO-AM. These in vitro results suggest that 4-HPR and NO pro-drugs may be effective chemopreventive agents against bone metastatic breast cancer.

Cell membrane fatty acid composition differs between normal and malignant cell lines

Twenty-eight fatty acids (C8:0 to C24:l n-9) were measured by gas chromatography in four normal cell lines (C3H / 10T1 / 2, CCD-18Co, CCD-25SK and CCD-37Lu) and seven cancer cell lines (C-41, Caov-3, LS-180, PC-3, SK-MEL-28, SK-MES-1 and U-87 MG). Results show differences in the content and proportions of fatty acids when comparing cancer cell lines with their normal counterparts. Cancer cell lines showed lower C20: 4 n-6, C24:1 n-9, polyunsaturated fatty acids (PUFA's) and ratios of C20:4 n-6 to C20:5 n-3 and C16:0 to C18:1 n-9 and stearic to oleic (SA/OA) than their normal counterparts. All cancer cell lines had SA/OA ratios lower than 7.0 while normal cell lines had ratios greater than 0.7 (p<0.05). In addition, the ratios of total saturated fatty acids (SFA) to PUFA'S and the concentration of C18:1 n-9, C18:2 n-6, C20:5 n-3 were higher in cancer cell lines as compared to normal cell lines. A positive correlation was detected between C16:0 and longer SFA'S (r = +0.511, p<0.05) in normal cell lines whereas a negative correlation (r=0.608, p<0.05) was obtained for malignant cell lines. Moreover, cancerous cell lines exhibited a particular desaturation defect and an abnormal incorporation of C18:2 n-6 and C20-4 n-6 fatty acids.

Development of echolocation calls in the mustached bat, Pteronotus parnellii

Adult mustached bats employ Doppler-sensitive sonar to hunt fluttering prey insects in acoustically cluttered habitats. The echolocation call consists of 4-5 harmonics, each composed of a long constant frequency (CF) component flanked by brief frequency modulations (FM). The 2nd harmonic CF component (CF2) at 61 kHz is the most intense, and analyzed by an exceptionally sharply tuned auditory system. The maturation of echolocation calls and the development of Doppler-shift compensation was studied in Cuba where large maternity colonies are found in hot caves. In the 1st postnatal week, infant bats did not echolocate spontaneously but could be induced to vocalize CF-FM signals by passive body motion. The CF2 frequency emitted by the smallest specimens was at 48 kHz (i.e., 0.4 octaves lower than the adult signal). CF-FM signals were spontaneously produced in the 2nd postnatal week at a CF2 frequency of 52 kHz. The CF2 frequencies of induced and spontaneous calls shifted upward to reach a value of 60.5 kHz in the 5th postnatal week. Standard deviations of CF2 frequency were large (up to +/-1.5 kHz) in the youngest bats and dropped to values of +/-250 Hz at the end of the 3rd postnatal week. Some individuals in the 4th and 5th postnatal weeks emitted with adultlike frequency precision of about +/-100 Hz. In the youngest bats, the 1st harmonic CF component (CF1) was up to 22 dB stronger than CF2. Adultlike relative levels of CF1 (-28 dB relative to CF2) were reached in the 5th postnatal week. In spontaneously emitted CF-FM calls, the duration of the CF2 component gradually increased with age from 5 ms to maximum values of 18 ms. Durations of the CF2 component in induced calls averaged 7 +/- 2.6 ms in the 1st postnatal week and 8.2 +/- 1.5 ms in the 5th postnatal week. There were no age-related changes in duration of the terminal FM sweep (3 +/- 0.4 ms) in both induced and spontaneous calls. The magnitude of the terminal FM sweep in spontaneous calls was not correlated with age (mean 13.5 +/- 2 kHz). Values for induced calls slightly increased with age from 11 +/- 2 to 13 +/- 2 kHz. The emission rate of induced CF-FM signals increased with age from values of 2.5 +/- 2 to 17 +/- 5 pulses/s. Values for spontaneously emitted calls were 4.4 +/- 3 and 9 +/- 4.5 pulses/s, respectively. Doppler-shift compensation, as tested in the pendulum task, emerged during the 4th postnatal week in young bats that were capable of very brief active flights, but before the time of active foraging outside the cave.

[Characterization of neuronal ceroid lipofuscinosis in Venezuelan children]

INTRODUCTION

Neuronal ceroid lipofuscinosis (NCL), represents a group of inherited neurodegenerative disorders. Based on the age of the patient at onset, clinical course and ultrastructural morphology it has been identified three clinical types for the pediatric group: 1) Infantile NCL (INCL); 2) Late infantile NCL (LINCL); and 3) Juvenile NCL (JNCL). Other variants or atypical forms represent around 20% of the NCL in different populations. Genetic advances have made possible a better characterization, diagnostic and classification of these disorders.

CASE REPORTS

We present the clinical, neurophysiological, neuroradiological, and morphological data from 6 patients with NCL, who were assessed at the pediatric neurology department of the Hospital Universitario de Maracaibo during a ten years period (1993 2003). All 6 cases corresponded with the late infantile form. Age of onset ranged form 2 to 5 years. For most of the patients initial symptoms included seizures, psychomotor delay, accompanied by macular degeneration and optic atrophy. The EEG was characterized by high voltage spikes elicited by low frequency photic stimulation, in 5 cases. Neuroimaging findings were characteristic of the late infantile form of the NCL. In three patients a decreased intensity of signal was seen in the thalami and putamen on T2-weighted images. The ultrastructural examination of the samples obtained through a biopsy showed curvilinear bodies in all patients.

CONCLUSION

There is not epidemiological data of the NCL in Venezuela; it is presumed the presence of clinical forms and variants in the pediatric group. This first study could contribute to the knowledge and a better research of this group of disorders in our population.

Postnatal Development of Cochlear Function in the Mustached Bat,Pteronotus parnellii

Postnatal development of the mustached bat's cochlea was studied by measuring cochlear microphonic and compound action potentials. In adults, a cochlear resonance is involved in enhanced tuning to the second harmonic constant frequency component (CF2) of their echolocation calls at ∼61 kHz This resonance is present immediately after birth in bats that do not yet echolocate. Its frequency is lower (46 kHz) and the corresponding threshold minimum of cochlear microphonic potentials is broader than in adults. Long-lasting ringing of the cochlear microphonic potential after tone stimulus offset that characterizes the adult auditory response close to CF2 is absent in newborns. In the course of the first 5 postnatal weeks, there is a concomitant upward shift of CF2 and the frequency of cochlear threshold minima. Up to the end of the third postnatal week, sensitivity of auditory threshold minima and the Q value of the cochlear resonance increase at a fast rate. Between 2 and 4 wk of age, two cochlear microphonic threshold minima are found consistently in the CF2 range that differ in their level-dependent dynamic growth behavior and are 1.5–5.7 kHz apart from each other. In older animals, there is a single minimum that approaches adult tuning in its sharpness. The data provide evidence to show that during maturation of the cochlea, the frequency and the sensitivity of the threshold minimum associated with CF2 increases and that these increases are associated with the fusion of two resonances that are partly dissociated in developing animals.

[Computerized modification of Fukuda test]

OBJECTIVES

To study a new method to apply to Fukuda test in order to overcome the interpretational difficulty associated with a subjective evaluation of the exam.

MATERIALS AND METHODS

During the exam, the patient wears a specially-designed headpiece, with a band at the back fitted with a sensor accommodating both a gyroscope and a bi-axial accelerometer. When asked to step in place, he does so in the Romberg position, eyes closed, successively rotating his head to the right and to the left.

RESULTS

On analyzing the data obtained through the laterality variable (right/left oscillation) and time variable, it resulted that the difference between the averages referring to the laterality variable of right-handed and left-handed subjects was statistically significant (P = 0.001), while the difference between the averages of the time variable was not.

CONCLUSIONS

To be able to propose an evaluation of the clinical validity of the test, further research must be carried out on pathological subjects, thus verifying the applicability of the method to the full.

[Balloon pulmonary valvuloplasty in a 1,680 g preterm infant]

We report a preterm infant weighing 1,680-g with critical pulmonary stenosis. Pulmonary balloon valvuloplasty was successfully performed using a = 1.15 balloon/annulus ratio.

Computerized brain tomography in patients with Schizophrenia

We carried out brain tomography of 27 patients with schizophrenia and 17 normal control subjects. DSM-IV criteria were used for diagnosis. The parameters studied were: brain volume, lateral and third ventricles, brain surface and brain indexes. Previously the patients were evaluated with the following clinical scales: Positive and Negative Syndrome Scale (PANSS), Brief Psychiatric Rating Scale (BPRS), Global Assessment of Functioning Scale (GAF) and the GRAFFAR scale to evaluate cultural and socioeconomical levels. We detected an increase in the right and left lateral ventricles: brain ratios, an increase in the width of Sylvian fissures and in the third ventricle index. We did not find differences that could be related to sex or to a familial history of mental disease. No differences were observed in the group receiving medication when compared with the group of untreated patients.

Receptor cell habituation in the A1 auditory receptor of four noctuoid moths

Moths of both sexes of Empyreuma affinis (=pugione) and Syntomeida epilais (Arctiidae, Ctenuchinae), Maenas jussiae (Arctiidae, Arctiinae) and Spodoptera frugiperda (Noctuidae, Amphipyrinae) were studied. Spike activity in the A1 cell was recorded using a stainless-steel hook electrode from the tympanic nerve in the mesothorax. Acoustic stimuli consisting of 25 and 100 ms pulses at the best frequency for the species and at intensities that evoke A1 cell saturation response were used at repetition rates of 0.5 and 5 Hz for 100 ms stimuli, and between 2 and 20 Hz for 25 ms stimuli. Stimuli at a repetition rate corresponding to a duty cycle of 5 % (25 ms at 2 Hz and 100 ms at 0.5 Hz) did not evoke monotonic changes in the responses of the A1 cell. With 25 ms pulses, rates above 5 Hz evoked an exponential decrease in the number of spikes and an increase in the latency of the responses of all the 37 specimens tested. The response duration showed no apparent change with stimulus repetition rates even at the highest duty cycle used (50 %), i.e. 25 ms at 20 Hz and 100 ms at 5 Hz. The higher the rate of stimulus repetition, the more marked were the changes in the A1 cell responses. In 16 of 17 preparations from two species, habituation had no effect on the adaptation rate in each response, while in seven of eight specimens of another species, the adaptation rate decreased with stimulus repetition. These results, and those from another mechanoreceptor cell, indicate that receptor cell adaptation (changes evoked in the response by a stimulus of constant intensity) and habituation (changes in the responses due to stimulus repetition rate) are two distinctive phenomena. The A1 cell in its habituated state showed an increase in its response to incremental increases in stimulus intensity of 10 dB. This result supports the idea that receptor cell habituation does not seem to be due to fatigue, i.e. to a temporary loss of the ability to respond to stimulation induced in a sensory receptor by continued stimulation.

Prognostic value of gastric intramucosal pH in critically ill children

OBJECTIVE

To determine the association of tonometrically measured gastric intramucosal pH (pHi) to the occurrence of multiple organ dysfunction syndrome (MODS) and death in critically ill children.

DESIGN

Prospective, observational study.

SETTING

Pediatric intensive care unit (ICU) of a teaching children's hospital.

PATIENTS

Fifty-one critically ill children admitted (median age 5.4+/-5 [SD] yrs; range 1 mo to 16 yrs) with the following diagnoses: post major surgery (n=26), sepsis (n=8), multiple trauma (n=5), acute respiratory distress syndrome (n=4), and "miscellaneous" (n=8).

INTERVENTIONS

Placement of a tonometric catheter.

MEASUREMENTS AND MAIN RESULTS

Pediatric Risk of Mortality (PRISM) score and clinical data were collected on admission and pHi daily during their stay in the pediatric ICU. A sigmoid tonometer was used to determine the pHi. Unconditional logistic regression was used to investigate the prognostic value of pHi. On admission, 26 patients presented with low gastric pHi (< or =7.35) and 17 of them had values of <7.30. The mortality rate in children with pHi <7.30 was 47.1% (95% confidence interval, 26.2 to 69) in contrast with an 11.7% mortality rate (95% confidence interval, 4.6 to 26.6) in children having a pHi of > or =7.30 (p=.015). The pHi and PRISM score on admission were independent predictive factors of death. The risk of mortality is increased when the pHi is low (odds ratio=2.5). However, we did not find the pHi to be a predictor for developing MODS.

CONCLUSIONS

Our results show that pHi is an independent predictor of mortality in patients admitted to a pediatric ICU. Although no relationship was observed between the risk of MODS and gastric pHi, the univariate difference of 21% vs. 41% is highly suggestive. The pHi determination is a minimally invasive procedure and well tolerated in children of all ages.

[Outbreak of asthma caused by soybean dust allergy. Clinical and immunologic study of the affected patients]

BACKGROUND

To study the clinical and immunological data of patients affected by a soybean asthma outbreak in Tarragona, Spain.

PATIENTS AND METHODS

Characteristics of previous asthma, emergency rooms records and immediate outcome of 15 patients who attended emergency room departments the epidemic day were recorded. Functional respiratory studies, skin prick tests to aeroallergens, and prick tests, specific IgE and immunoblotting to soybean extracts were performed in all patients.

RESULTS

Thirteen patients were sensitized to soybean proteins. All of them were atopic (most sensitized to house dust mites) and half had started asthma symptoms after their thirties. The epidemic crisis was particularly severe in patients over 50 years, daily chronic asthma, severe obstructive pattern and/or non receiving steroids. Four patients were admitted to intensive care units. Seven patients showed asthma exacerbations (late reactions) 24 h after the beginning of the epidemic crisis. Specific IgE against a 5-6 kD and a 15.5-17 kD soybean proteins was detected in the sera of 8 patients and 10 patients, respectively.

CONCLUSIONS

The outbreak affected atopic patients exposed to soybean dust. The severity of the crisis was related with the previous severity of asthma. Besides the well known 5-6 kD allergenic soybean protein, the 15.5-17 kD protein seems also to be implicated in the sensitization of most of these patients.

Compounding Fumed Silicas into Polydimethylsiloxane: Bound Rubber and Final Aggregate Size

The properties of mechanically mixed suspensions of fumed silicas in polydimethylsiloxane (PDMS) were studied. The work focuses on two aspects: (i) Adsorption of PDMS onto silicas by means of the mechanical mixing of the bulk polymer and untreated or chemically modified fumed silicas. The silica-PDMS suspensions were completely dispersed or only swollen by a solvent, depending on the filler concentration, the silica surface chemistry, and the polymer molecular weight. The bound rubber content of the different preparations was determined by a weight difference technique and by carbon analysis of the samples and was compared with previously reported values in similar systems. (ii) The effect of the mechanical mixing on the final aggregate size of the silica and on the polymer molecular weight distribution. One PDMS and silicas of different surface area and surface chemistry were used. The final size of the aggregates after a long mixing time with the bulk polymer was approximately the same in all cases. Copyright 1997 Academic Press. Copyright 1997Academic Press

Cell kinetics and tumor regression during radiotherapy in head and neck squamous-cell carcinomas

Head and neck squamous-cell carcinoma (HN-SCC) patient management is mainly based on TNM classification and needs be improved by considering other potentially useful prognostic factors. We examined the pre-radiotherapy tumor potential doubling time (Tpot) evaluated after in vivo infusion of bromodeoxyuridine and flow-cytometric analysis and the early clinical tumor regression after 40 Gy (40 Gy-TR). Tpot values and clinical 40 Gy-TR classes (minor and major) were available for 82 HN-SCC patients. Radiation therapy completion was done either with 1 dose per day (conventional regimen) or 2 doses per day (accelerated regimen). Local control was also available for follow-up times above 4 years. We found that major 40 Gy-TR was strongly correlated with fast tumor growth, characterized by Tpot values below 5 days, and that patients with major 40 Gy-TR showed better local control than those with minor 40 Gy-TR, independently from the radiotherapy regimen type. We also found that treatment completion with accelerated radiotherapy gave better local control for patients with major 40 Gy-TR and fast tumor growth than conventional radiotherapy. Multivariate analysis, performed on all patients, assigned an independent prognostic value to Tpot, tumor classification and 40 Gy-TR.