Dosimetric and toxicity comparison between Syed-Neblett and Fletcher-Suit-Delclos Tandem and Ovoid applicators in high dose rate cervix cancer brachytherapy

PURPOSE

To compare patient and tumor characteristics, dosimetry, and toxicities between interstitial Syed-Neblett and intracavitary Fletcher-Suit-Delclos Tandem and Ovoid (T&O) applicators in high dose rate (HDR) cervical cancer brachytherapy.

METHODS

A retrospective analysis was performed for cervical cancer patients treated with 3D-based HDR brachytherapy from 2011 to 2023 at a single institution. Dosimetric parameters for high-risk clinical target volume and organs at risk were obtained. Toxicities were evaluated using the Common Terminology Criteria for Adverse Events version 5.0.

RESULTS

A total of 115 and 58 patients underwent Syed and T&O brachytherapy, respectively. Patients treated with Syed brachytherapy were more likely to have larger tumors and FIGO stage III or IV disease. The median D2cc values to the bladder, small bowel, and sigmoid colon were significantly lower for Syed brachytherapy. Patients treated with Syed brachytherapy were significantly more likely to be free of acute gastrointestinal (44% vs. 21%, p = 0.003), genitourinary (58% vs. 36%, p = 0.01), and vaginal toxicities (60% vs. 33%, p = 0.001) within 6 months following treatment compared to patients treated with T&O applicators. In contrast, Syed brachytherapy patients were more likely to experience late gastrointestinal (68% vs. 49%, p = 0.082), genitourinary (51% vs. 35%, p = 0.196), and vaginal toxicities (70% vs. 57%, p = 0.264).

CONCLUSIONS

Syed-Neblett and T&O applicators are suitable for HDR brachytherapy for cervical cancer in distinct patient populations. Acute toxicities are more prevalent with T&O applicators, while patients treated with Syed-Neblett applicators are more likely to develop late toxicities.

Verrucous carcinoma of the vulva: Patterns of care and treatment outcomes

BACKGROUND

Verrucous vulvar carcinoma (VC) is an uncommon and distinct histologic subtype of squamous cell carcinoma (SCC). The available literature on VC is currently limited to case reports and small single institution studies.

AIMS

The goals of this study were to analyze data from the National Cancer Database (NCDB) to quantitate the incidence of VC and to investigate the effects of patient demographics, tumor characteristics, and treatment regimens on overall survival (OS) in women with verrucous vulvar carcinoma.

METHODS AND RESULTS

Patients diagnosed with vulvar SCC or VC between the years of 2004 and 2016 were identified in the NCDB. OS was assessed with Kaplan-Meier curves and the log-rank test. Construction of a Cox model compared survival after controlling for confounding variables. The reported incidence of SCC of the vulva has significantly increased since 2004 (p < .0001). In contrast, the incidence of VC has remained stable (p = .344) since 2004. Compared to SCC, VC was significantly more likely to be diagnosed in older women (p < .0001) and treated with surgery alone (p < .0001). However, on propensity score weighted analysis there was a trend toward improved 5-year OS in women with VC compared to those with SCC (63.4% vs. 57.7%, p = .0794). Multivariable Cox survival analysis showed an improvement in OS in VC patients treated with both primary site and regional lymph node surgery compared to primary site surgery alone (adjusted hazard ratio [aHR] 0.67, 95% confidence interval [CI] 0.46-0.97, p = .0357).

CONCLUSION

Verrucous carcinoma is more likely to present in older women. Regional lymph node surgery in addition to primary site surgery significantly improves OS in VC patients.

Trends in Incidence and Mortality Rates of Uterine Cancer in Kentucky

OBJECTIVES

The objective of this analysis was to gauge how the incidence and mortality of uterine cancer in Kentucky have changed from 1995 through 2017. An assessment of the trends in incidence and mortality across different geographic areas and between different races was also performed.

METHODS

Age-adjusted annual incidence and mortality rates for uterine cancer were obtained from the Kentucky Cancer Registry. A meta-regression framework was used to assess changes in incidence and mortality rates during the time frame and to determine differences in these rates between rural versus urban counties, Appalachian versus non-Appalachian counties, and Black versus White women.

RESULTS

The incidence of uterine cancer has significantly increased throughout the state of Kentucky since 1995. Uterine cancer incidence was 10% and 22% higher in rural and Appalachian counties, respectively, compared with urban and non-Appalachian counties (P < 0.0001) from 1995 through 2017. In contrast, urban and non-Appalachian women had higher or equivalent age-adjusted mortality from uterine cancer, compared with rural and Appalachian women, respectively. The incidence of uterine cancer was significantly higher in White women compared with Black women from 1995 through 2006, but since 2007, there has been no significant difference in uterine cancer incidence based on race. Black women had higher age-adjusted mortality than White women throughout the entire time period examined.

CONCLUSIONS

The incidence of uterine cancer is higher in rural and Appalachian Kentucky, without a corresponding geographic trend in mortality. Uterine cancer mortality is significantly higher in Black women.

Patterns of care and outcomes of radiotherapy or hormone therapy in patients with medically inoperable endometrial adenocarcinoma

OBJECTIVE

The optimal treatment for medically inoperable endometrioid endometrial adenocarcinoma is unknown. The goal of this study was to evaluate the patterns of care and efficacy of radiotherapy (RT) or hormone therapy (HT) in the treatment of these patients.

METHODS

We performed a query of the National Cancer Database (NCDB) of patients with medically inoperable endometrioid adenocarcinoma of the endometrium diagnosed between 2004 and 2016 and treated with either RT or HT. A multivariate Cox regression model and propensity weighted analyses were used to evaluate overall survival after controlling for confounding variables. A multinomial logistic regression model was used to assess predictors of RT or HT use.

RESULTS

A total of 1036 patients were included in this cohort, and 73% (n = 759) were treated with RT alone. Patients who received definitive HT compared to RT were more likely to be older, diagnosed in the earlier years of this analysis, treated at lower-case volume centers, diagnosed with high-grade disease, or located outside of metropolitan areas. On multivariate analysis, treatment with HT alone versus RT alone was associated with significantly worse overall survival in the multivariate Cox model but not on propensity score weighted analysis. Interaction effect testing revealed that older patients and those treated at lower-volume centers had improved survival with RT compared to HT.

CONCLUSIONS

We identified factors associated with the receipt of RT or HT in medically inoperable endometrial cancer patients. Treatment with RT correlated with improved survival compared to HT in older patients and those treated at lower-volume centers.

Role of adjuvant chemotherapy in patients with FIGO stage IB grade 3 endometrial endometrioid adenocarcinoma treated with surgery and post-operative radiotherapy

BACKGROUND

The optimal treatment of patients with FIGO stage IB grade 3 endometrial endometrioid adenocarcinoma remains unknown.

OBJECTIVE

To compare overall survival following treatment with a hysterectomy and adjuvant radiotherapy with or without chemotherapy in this group of patients.

METHODS

Patients diagnosed between January 2004 and January 2016 with FIGO stage IB grade 3 endometrial endometrioid adenocarcinoma treated with hysterectomy and postoperative radiotherapy with or without adjuvant concurrent chemotherapy were identified in the National Cancer Database. Overall survival was assessed with Kaplan-Meier curves. A Cox model was constructed to evaluate survival after controlling for confounding variables. A logistic regression model was used to reveal predictors of chemotherapy use.

RESULTS

A total of 2173 patients were included. The receipt of chemotherapy was associated with an increased 5-year overall survival from 67.6% to 75.6% (p=0.0313). This association trended toward statistical significance on multivariate analysis (adjusted HR (aHR) 0.80; 95% CI 0.63 to 1.01; p=0.0653). Other factors associated with improved survival were undergoing a lymphadenectomy, absence of lymphovascular space invasion, younger age, smaller tumor size, non-black race, and absence of comorbidities. Patients who underwent brachytherapy, had lymphovascular space invasion, were younger, were diagnosed in the more recent years, and were treated in higher volume centers were more likely to receive adjuvant chemotherapy.

CONCLUSION

Adjuvant chemotherapy and radiation therapy were associated with an increase in survival in patients with FIGO stage IB grade 3 endometrial endometrioid adenocarcinoma compared with those treated with adjuvant radiotherapy alone.

Integrating a 92-Gene Expression Analysis for the Management of Neuroendocrine Tumors of Unknown Primary

Background: Neuroendocrine tumors (NETs) are rare tumors that can originate from any part of the body. Often, imaging or exploratory surgery can assist in the identification of the tumor primary site, which is critical to the management of the disease. Neuroendocrine tumors (NETs) of unknown primary constitute approximately 10-15% of all NETs. Determining the original site of the tumor is critical to providing appropriate and effective treatment. Methods: We performed a retrospective review of neuroendocrine tumors at our institution between 2012 and 2016 using a 92-gene cancer ID analysis. Results: 56 patients with NETs of unknown primary were identified. Samples for 38 of the 56 underwent the 92-gene cancer ID analysis. The primary site of the tumor was identified with >95% certainty in 35 of the 38 patients. Conclusion: The 92-gene cancer ID analysis identified a primary site in 92% of our NETs study cohort that previously had been unknown. The results have direct implications on management of patients with regard to FDA-approved treatment options.

Isolation from natural habitat reduces yield and quality of passion fruit

Loss and fragmentation of native vegetation negatively affect crop pollinators and productivity of several crop species. The yellow passion fruit is an excellent model to investigate this issue, because its main pollinators are sensitive to deforestation. Seasonality also influences fruit set of crop species that are pollinated by bees. Climate determines plant flowering patterns and consequently affects pollinator activity. Little is known on effects of pollinators on crop quality in general, and particularly of many tropical fruits that have multiple fruiting seasons throughout the year, such as passion fruit. Our hypothesis is that the distance to the native vegetation and climate seasonality affect the pollination and fruit production of cultivated, hermaphrodite, self-incompatible, protandrous species that depend on large-sized bees to set fruit. We observed flowers of the yellow passion fruit in eight areas at different distances (600-4,000 m) from a dry seasonal forest (Caatinga). We compared the frequency of the main floral visitor (pollinators and robbers) visits and fruit set among areas at the beginning and end of the dry and rainy seasons. Xylocopa species were pollinators, and Apis mellifera, Trigona spinipes and a hummingbird were robbers. Xylocopa visits diminished with increasing distance to native remnants, converse to what was observed for the robbers at the beginning of the dry season. Fruit set was higher at the beginning of the dry season. The distance to the forest affected quality of fruits in terms of length, diameter and skin thickness, which all decreased with increase in remnant distance. Our results show that insect pollination is higher in the dry season, increasing profitability and reducing labour costs for the producer. Considering the influence of distance to native vegetation on pollination, robbery and fruit quality, our study reinforces the necessity for conservation of native vegetation remnants.

Does adjuvant concurrent or sequential chemotherapy increase the radiation-related toxicity of vaginal brachytherapy for endometrial cancer patients?

PURPOSE

To compare radiation toxicity in endometrial cancer patients treated with adjuvant vaginal brachytherapy (VBT) vs. VBT with concurrent chemotherapy (CCT) or sequential chemotherapy (SCT) METHODS: We retrospectively analyzed 131 patients with endometrial cancer treated with VBT without external beam radiation therapy. Toxicities were graded according to the Common Terminology Criteria for Adverse Events v4.03. CCT was defined as VBT delivered between the first and last cycle of chemotherapy (CT); SCT was defined as VBT delivered before or after CT.

RESULTS

Median followup was 36 months, with a 3-year survival rate of 88%. Of the 131 patients, 92 were treated with VBT alone, 34 with VBT and CCT, and 5 with VBT and SCT. The most common toxicity was vaginal stricture, with 30 (22.9%) patients affected. The distribution of toxicities was vaginal 28%, urinary 12%, rectal 11%, and fatigue 5%; none greater than Grade 2. Compared with patients treated with VBT alone, the addition of CT did not increase the chance of vaginal stricture formation (p = 0.84). The difference in system-specific toxicities between treatment modalities was not statistically significant.

CONCLUSION

The most common pelvic toxicity from VBT is vaginal stenosis with other toxicities being infrequent and generally Grade 1. The addition of CT in a sequential or concurrent fashion did not increase the rate of pelvic toxicity from VBT alone.

Clinical Application of a Hybrid RapidArc Radiotherapy Technique for Locally Advanced Lung Cancer

OBJECTIVE

Radiation treatment planning for locally advanced lung cancer can be technically challenging, as delivery of ≥60 Gy to large volumes with concurrent chemotherapy is often associated with significant risk of normal tissue toxicity. We clinically implemented a novel hybrid RapidArc technique in patients with lung cancer and compared these plans with 3-dimensional conformal radiotherapy and RapidArc-only plans.

MATERIALS/METHODS

Hybrid RapidArc was used to treat 11 patients with locally advanced lung cancer having bulky mediastinal adenopathy. All 11 patients received concurrent chemotherapy. All underwent a 4-dimensional computed tomography planning scan. Hybrid RapidArc plans concurrently combined static (60%) and RapidArc (40%) beams. All cases were replanned using 3- to 5-field 3-dimensional conformal radiotherapy and RapidArc technique as controls.

RESULTS

Significant reductions in dose were observed in hybrid RapidArc plans compared to 3-dimensional conformal radiotherapy plans for total lung V20 and mean (-2% and -0.6 Gy); contralateral lung mean (-2.92 Gy); and esophagus V60 and mean (-16.0% and -2.2 Gy; all P < .05). Contralateral lung doses were significantly lower for hybrid RapidArc plans compared to RapidArc-only plans (all P < .05). Compared to 3-dimensional conformal radiotherapy, heart V60 and mean dose were significantly improved with hybrid RapidArc (3% vs 5%, P = .04 and 16.32 Gy vs 16.65 Gy, P = .03). However, heart V40 and V45 and maximum spinal cord dose were significantly lower with RapidArc plans compared to hybrid RapidArc plans. Conformity and homogeneity were significantly better with hybrid RapidArc plans compared to 3-dimensional conformal radiotherapy plans ( P < .05). Treatment was well tolerated, with no grade 3+ toxicities.

CONCLUSION

To our knowledge, this is the first report on the clinical application of hybrid RapidArc in patients with locally advanced lung cancer. Hybrid RapidArc permitted safe delivery of 60 to 66 Gy to large lung tumors with concurrent chemotherapy and demonstrated advantages for reduction in low-dose lung volumes, esophageal dose, and mean heart dose.

Biotechnology advances: a perspective on the diagnosis and research of Rabies Virus

Rabies is a widespread zoonotic disease responsible for approximately 55,000 human deaths/year. The direct fluorescent antibody test (DFAT) and the mouse inoculation test (MIT) used for rabies diagnosis, have high sensitivity and specificity, but are expensive and time-consuming. These disadvantages and the identification of new strains of the virus encourage the use of new techniques that are rapid, sensitive, specific and economical for the detection and research of the Rabies Virus (RABV). Real-time RT-PCR, phylogeographic analysis, proteomic assays and DNA recombinant technology have been used in research laboratories. Together, these techniques are effective on samples with low virus titers in the study of molecular epidemiology or in the identification of new disease markers, thus improving the performance of biological assays. In this context, modern advances in molecular technology are now beginning to complement more traditional approaches and promise to revolutionize the diagnosis of rabies. This brief review presents some of the recent molecular tools used for RABV analysis, with emphasis on rabies diagnosis and research.

Abstract 4251: Inhibition of membrane bound and soluble VEGF receptor-2 activity enhances the proliferation of the BON carcinoid cell line

There is a growing interest in using angiogenesis inhibitors to treat neuroendocrine tumors. Previously, we detected the expression of vascular endothelial growth factor receptor-2 (VEGFR-2) and its soluble isoform (sVEGFR-2) in the epithelial component of carcinoid tumors and in the BON carcinoid cell line. Recent studies have demonstrated that VEGF inhibitors transiently inhibit tumor growth, followed by increased tumor invasion and metastasis. Also, we have reported that shRNA reduction of VEGFR-2 increases BON cell proliferation and invasion. Thus, the purpose of our current study was to: i) assess the effect that the VEGF signaling inhibitors bevacizumab, an antibody against VEGF-A, or sunitinib, a small molecule inhibitor of VEGFR-2, have on BON cell proliferation and, ii) evaluate the effect of knockdown and overexpression of sVEGFR-2 on BON cell proliferation. Methods. i) BON cells were cultured in media supplemented with bevacizumab (50 ng/ml), sunitinib (50 ng/ml), or vehicle control for two weeks. Media was replaced every other day, and cell lysates for western blot and RNA analysis were collected after one and two weeks. After two weeks, cell proliferation was measured using a cell counting kit-8 assay. ii) Knockdown or upregulation of sVEGFR-2 was achieved by transfecting BON cells with shRNA to sVEGFR-2 or a cDNA plasmid expressing the sVegfr2 gene, respectively. Proliferation following sVEGFR-2 knockdown or upregulation was determined and compared to cells transfected with the appropriate controls. Results. i) BON cell proliferation was significantly increased in cells treated with bevacizumab or sunitinib compared to vehicle control. Western blot analysis demonstrated an increase in phospho-ERK and phospho-Akt following treatment with bevacizumab. Interestingly, there were no observed changes in activation of ERK or Akt following treatment with sunitinib. However, sunitinib treatment increased protein and mRNA expression of VEGFR-2, as assessed by western blot and qRT-PCR, respectively. ii) BON cells with reduced expression of sVEGFR-2 demonstrated increased proliferation at 24 h, 48 h, 72 h, 96 h, and 120 h following plating. Conversely, BON cells transfected with plasmid cDNA encoding sVEGFR-2 displayed reduced proliferation at the aforementioned time points compared to cells transfected with empty plasmid. Conclusions. We have demonstrated that the VEGF inhibitors bevacizumab and sunitinib can enhance the proliferation of BON cells in vitro and that sVEGFR-2 inhibits BON cell proliferation, possibly by sequestering VEGF ligands. While VEGF inhibitors have been shown to effectively inhibit angiogenesis, they may also enhance the aggressiveness of surviving tumor cells, suggesting that a multimodal treatment plan is warranted in carcinoid patients.

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 4251. doi:10.1158/1538-7445.AM2011-4251

The effect of PTEN on serotonin synthesis and secretion from the carcinoid cell line BON

BACKGROUND

Carcinoid tumors are associated with the carcinoid syndrome, a set of symptoms resulting from the peptide and amine products, including serotonin, secreted from the cancer cells. The purpose of this study was to investigate the relationship between the phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) inhibitor PTEN (phosphatase and tensin homolog deleted on chromosome ten) and serotonin synthesis and secretion in the carcinoid cancer cell line BON.

MATERIALS AND METHODS

PTEN was inhibited by pharmacological and molecular approaches, and the resultant secretion of serotonin and expression of tryptophan hydroxylase 1 (TPH1), the rate-limiting enzyme in serotonin synthesis, was assessed.

RESULTS

Inhibition of PTEN in vitro, with concomitant increased Akt signaling, resulted in decreased secretion of serotonin, as well as decreased serotonin synthesis, as confirmed by reduced expression of TPH1. Inhibition of PTEN in BON cells in an animal model resulted in decreased serum serotonin.

CONCLUSION

By inhibiting signaling through Akt, PTEN indirectly promotes serotonin synthesis and secretion.

Muscle fiber type characterization and myosin heavy chain (MyHC) isoform expression in Mediterranean buffaloes

This study aimed to evaluate myosin heavy chain (MyHC) isoform expression and muscle fiber types of Longissimus dorsi (LD) and Semitendinosus (ST) in Mediterranean buffaloes and possible fibers muscles modulation according to different slaughter weights. The presence of MyHC IIb isoforms was not found. Only three isoforms of MyHC (IIa, IIx/d and I) were observed and their percentages did not vary significantly among slaughter weights. The confirmation of the presence of hybrid muscles fibers (IIA/X) in LD and ST muscles necessitated classifying the fiber types into fast and slow according to their contractile activity, by m-ATPase assay. For both muscles, the muscle fiber frequency was higher for fast than for slow fibers in all weight groups. There was a difference (P<0.05) in the frequency of LD and ST muscle fiber types according to slaughter weights, which demonstrate that the slaughter weight influences the profile of muscle fibers from buffaloes.

VEGFR-2 expression in carcinoid cancer cells and its role in tumor growth and metastasis

Carcinoid tumors are slow growing and highly vascular neuroendocrine neoplasms that are increasing in incidence. Previously, we showed that carcinoid tumors express vascular endothelial growth factor receptor 2 (VEGFR-2) in the epithelial compartment of carcinoid tumor sections; yet, its role is not completely understood. The purpose of our study was to: (i) assess the expression of VEGFR-2 in the novel human carcinoid cell line BON, (ii) to determine the role of PI3K/Akt signaling on VEGFR-2 expression and (iii) to assess the effect of VEGFR-2 on BON cell invasion, migration and proliferation. We found that, although VEGFR-2 is expressed in BON cells, reduction in VEGFR-2 expression actually enhanced proliferation, invasion, and migration of the BON cell line. Also, expression of VEGFR-2 was inversely related to PI3K signaling. Carcinoid liver metastases in mice demonstrated decreased VEGFR-2 expression. Furthermore, the expression of a truncated, soluble form of VEGFR-2 (sVEGFR-2), a protein demonstrated to inhibit cell growth, was detected in BON cells. The presence of VEGFR-2 in the epithelial component of carcinoid tumors and in the BON cell line suggests an alternate role for VEGFR-2, in addition to its well-defined role in angiogenesis. The expression of sVEGFR-2 may explain the inverse relationship between VEGFR-2 expression and PI3K/Akt signaling and the inhibitory effect VEGFR-2 has on BON cell proliferation, migration and invasion.

Immunomodulatory effects of crotoxin isolated from Crotalus durissus terrificus venom in mice immunised with human serum albumin

Crotalus durissus terrificus venom and its main component, crotoxin (CTX), have the ability to down-modulate the immune system. Certain mechanisms mediated by cells and soluble factors of the immune system are responsible for the elimination of pathogenic molecules to ensure the specific protection against subsequent antigen contact. Accordingly, we evaluated the immunomodulatory effects of CTX on the immune response of mice that had been previously primed by immunisation with human serum albumin (HSA). CTX inoculation after HSA immunisation, along with complete Freund's adjuvant (CFA) or Aluminium hydroxide (Alum) immunisation, was able to suppress anti-HSA IgG1 and IgG2a antibody production. We showed that the inhibitory effects of this toxin are not mediated by necrosis or apoptosis of any lymphoid cell population. Lower proliferation of T lymphocytes from mice immunised with HSA/CFA or HSA/Alum that received the toxin was observed in comparison to the mice that were only immunised. In conclusion, CTX is able to exert potent inhibitory effects on humoral and cellular responses induced by HSA immunisation, even when injected after an innate immune response has been initiated.

Abstract 703: Suppression of neurotensin receptor type 1 expression and function by apigenin in human colorectal cancers involves protein kinase CK2/JNK pathway

Apigenin, a nonmutagenic chemopreventive agent found naturally in fruits and green vegetables, is an inhibitor of protein kinase CK2 (formerly casein kinase II), which is frequently upregulated in human cancers. Neurotensin (NT), a gut peptide, stimulates growth of colorectal cancers (CRCs) through its high affinity receptor (NTR1). In this study, we found that treatment with apigenin suppressed NTR1 expression in CRC cells HCT116, SW480 and SW620. Additionally, treatment with emodin, another natural inhibitor of CK2, and TBB (4,5,6,7-tetrabromo-1H-benzotriazole), a selective chemical inhibitor of CK2, suppressed NTR1 expression in these CRC cells, indicating that CK2 plays a role in NTR1 regulation. Moreover, apigenin significantly decreased phosphorylation of JNK1/2, whereas TBB decreased phosphorylation of JNK1 and emodin decreased phosphorylation of JNK2 in HCT116 cells; all three compounds decreased phosphorylation of JNK1 in SW480 cells. Treatment with the selective JNK1/2 inhibitor, SP600125, suppressed NTR1 expression in all CRC cell lines examined. Furthermore, apigenin significantly inhibited CRC cell proliferation and prevented NT-stimulated expression of IL-8, c-myc and Mcl-1, all which contribute to CRC proliferation or metastasis. We conclude that apigenin suppresses endogenous NTR1 expression and function in multiple CRC cell lines; this effect may involve CK2/JNK signaling. The downregulation of NTR1 in CRCs may represent an important mechanism for the anti-cancer effects of apigenin.

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 703.

Targeted inhibition of mammalian target of rapamycin signaling inhibits tumorigenesis of colorectal cancer

PURPOSE

The mammalian target of rapamycin (mTOR) kinase acts downstream of phosphoinositide 3-kinase/Akt to regulate cellular growth, metabolism, and cytoskeleton. Because approximately 60% of sporadic colorectal cancers (CRC) exhibit high levels of activated Akt, we determined whether downstream mTOR signaling pathway components are overexpressed and activated in CRCs.

EXPERIMENTAL DESIGN

HCT116, KM20, Caco-2, and SW480 human CRC cells were used to determine the effects of pharmacologic (using rapamycin) or genetic (using RNAi) blockade of mTOR signaling on cell proliferation, apoptosis, cell cycle progression, and subcutaneous growth in vivo.

RESULTS

We show that the mTOR complex proteins mTOR, Raptor, and Rictor are overexpressed in CRC. Treatment with rapamycin significantly decreased proliferation of certain CRC cell lines (rapamycin sensitive), whereas other cell lines were resistant to its effects (rapamycin resistant). Transient siRNA-mediated knockdown of the mTORC2 protein, Rictor, significantly decreased proliferation of both rapamycin-sensitive and rapamycin-resistant CRC cells. Stable shRNA-mediated knockdown of both mTORC1 and mTORC2 decreased proliferation, increased apoptosis, and attenuated cell cycle progression in rapamycin-sensitive CRCs. Moreover, stable knockdown of both mTORC1 and mTORC2 decreased proliferation and attenuated cell cycle progression, whereas only mTORC2 knockdown increased apoptosis in rapamycin-resistant CRCs. Finally, knockdown of both mTORC1 and mTORC2 inhibited growth of rapamycin-sensitive and rapamycin-resistant CRCs in vivo when implanted as tumor xenografts.

CONCLUSIONS

Targeted inhibition of the mTORC2 protein, Rictor, leads to growth inhibition and induces apoptosis in both rapamycin-sensitive and rapamycin-resistant CRCs, suggesting that selective targeting of mTORC2 may represent a novel therapeutic strategy for treatment of CRC.

An analysis of trends and growth factor receptor expression of GI carcinoid tumors

INTRODUCTION

The purpose of our study was twofold: (1) to determine the incidence, patient and tumor characteristics, and outcome of patients with gastrointestinal carcinoid tumors using the Surveillance, Epidemiology and End Results (SEER) database, and (2) to delineate the expression pattern of growth factor receptors (GFRs) in carcinoid tumors.

MATERIALS AND METHODS

The SEER database search provided information on patients diagnosed with carcinoid tumors from 1990 to 2002. Carcinoid tumor sections (n = 46) were stained for the GFRs: epidermal growth factor receptor, insulin-like growth factor receptor (IGFR), vascular endothelial growth factor receptor (VEGFR), and HER-2/neu.

RESULTS

Over the 12-year analysis period, 18,180 patients were identified with carcinoid tumors of the foregut, midgut, and hindgut; the incidence of carcinoid tumors increased approximately 2-fold during this time period. Of the patients with carcinoid tumors, there was a trend of increased expression of VEGFR and IGFR, particularly in the foregut and midgut carcinoids. Analysis of the SEER database confirms that the incidence of carcinoid tumors is increasing with an approximate doubling in the number of carcinoid cases from 1990 to 2002. Furthermore, an increase in VEGFR and IGFR expression suggests that GFR inhibitors may be effective adjuvant therapy for carcinoid cancer.

Development and characterization of a novel in vivo model of carcinoid syndrome

PURPOSE

Carcinoid syndrome, characterized by flushing, diarrhea, and valvular heart disease, can occur following carcinoid tumor metastasis to the liver and systemic release of bioactive hormones into the systemic circulation. Treatment of this devastating disease is hampered by the lack of an in vivo model that recapitulates the clinical syndrome.

EXPERIMENTAL DESIGN

Here, we have injected BON cells, a novel human carcinoid cell line established in our laboratory, into the spleens of athymic nude mice to establish liver metastases.

RESULTS

The majority of mice injected intrasplenically with BON cells developed significant increases in plasma serotonin and urine 5-hydroxyindoleacetic acid, and several mice exhibited mesenteric fibrosis, diarrhea, and fibrotic cardiac valvular disease reminiscent of carcinoid syndrome by both echocardiographic and histopathologic evaluation. Mice pretreated with octreotide, a long-acting somatostatin analogue, or bevacizumab, a vascular endothelial growth factor inhibitor, developed fewer liver metastases and manifestations of carcinoid syndrome, including valvular heart disease.

CONCLUSION

We have provided an important in vivo model to further delineate novel treatment modalities for carcinoid syndrome that will also be useful to elucidate the factors contributing to the sequelae of carcinoid disease (e.g., mesenteric fibrosis and valvular heart disease).

The value of in vivo real time ultrasonography in assessing loin muscularity and carcass composition of rabbits

Sixty nine growing rabbits were scanned over the lumbar region using a real time ultrasonography (RTU) machine to estimate loin muscularity and carcass composition. Longissimus thoracis et lumborum muscle (LM) depth, width and area were taken. Animals were weighed (LW), slaughtered and carcass composition was determined. Equivalent measurements to those taken by RTU in vivo were taken on the carcass and muscularity indices were calculated on carcass and in vivo. Simple correlations between the two types of measurements were determined and carcass composition was estimated by simple and multiple regressions. The LW varied from 1200 to 3410g. The simple correlations between carcass and in vivo RTU LM measurements were high (P<0.001) and the LM area was the trait with the highest correlation (r=0.92). Simple correlations between muscularity indices measured by RTU and in carcass were significant (P<0.001). In vivo RTU measurements explained a large amount of the variation of the carcass meat weight (MW) and bone weight (r(2) range from 0.49 to 0.77; P<0.001). Using multiple regression equations to estimate carcass composition, the best fit was obtained with the LW and one or more in vivo RTU measurement. The LW explained 90.6% of the variation of MW in the carcass. In vivo RTU is able to estimate loin muscularity and carcass composition of rabbits with accuracy. The usefulness of in vivo RTU and LW to predict carcass composition of rabbits using multiple regressions was also shown.

PKD3 is the predominant protein kinase D isoform in mouse exocrine pancreas and promotes hormone-induced amylase secretion

The protein kinase D (PKD) family of serine/threonine kinases, which can be activated by gastrointestinal hormones, consists of three distinct isoforms that modulate a variety of cellular processes including intracellular protein transport as well as constitutive and regulated secretion. Although isoform-specific functions have been identified in a variety of cell lines, the expression and function of PKD isoforms in normal, differentiated secretory tissues is unknown. Here, we demonstrate that PKD isoforms are differentially expressed in the exocrine and endocrine cells of the pancreas. Specifically, PKD3 is the predominant isoform expressed in exocrine cells of the mouse and human pancreas, whereas PKD1 and PKD2 are more abundantly expressed in the pancreatic islets. Within isolated mouse pancreatic acinar cells, PKD3 undergoes rapid membrane translocation, trans-activating phosphorylation, and kinase activation after gastrointestinal hormone or cholinergic stimulation. PKD phosphorylation in pancreatic acinar cells occurs viaaCa2+-independent, diacylglycerol- and protein kinase C-dependent mechanism. PKD phosphorylation can also be induced by physiologic concentrations of secretagogues and by in vivo stimulation of the pancreas. Furthermore, activation of PKD3 potentiates MEK/ERK/RSK (RSK, ribosomal S6 kinase) signaling and significantly enhances cholecystokinin-mediated pancreatic amylase secretion. These findings reveal a novel distinction between the exocrine and endocrine cells of the pancreas and further identify PKD3 as a signaling molecule that promotes hormone-stimulated amylase secretion.

Carcass composition and meat quality of equally mature kids and lambs

Carcass composition and meat quality attributes of 55 suckling kids (27 males and 28 females) and 57 suckling lambs (28 males and 29 females) of Portuguese native breeds were investigated. These suckling kid and lamb meats are European meat quality labels produced according to "Cabrito de Barroso- PGI" and "Borrego Terrincho-PDO" specifications, respectively. Female kids were slaughtered at 9.1 +/- 0.36 kg of BW, and male kids were slaughtered at 10.4 +/- 0.37 kg of BW, corresponding to 20.1 and 17.7% of maturity, respectively. Female lambs were slaughtered at 8.6 +/- 0.53 kg of BW, and male lambs were slaughtered at 9.9 +/- 0.23 kg of BW, corresponding to 19.9 and 17.1% of maturity, respectively. At 24 h postmortem, various yield and quality measurements were collected. The left sides of the carcasses were dissected into muscle, subcutaneous fat, intermuscular fat, and bone. Final pH, instrumental color (L*, a*, b*), carcass measurements, and kidney knob and pelvic fat were also determined. Samples of LM were taken from the lumbar and thoracic cuts for intramuscular and meat quality determinations. At 72 h postmortem, a sample of LM was used for cooking losses and Warner-Bratzler shear force determination. Suckling lambs had greater dressing proportion than suckling kids (P < 0.01). Carcass fatness was not affected by species (P > 0.05), but females had greater kidney knob and pelvic fat proportion than males (P < 0.01). Lambs had greater proportions of the highly valued leg cut and lower proportions of shoulder, anterior rib, and neck cuts than kids. Dissection results indicated that kid carcasses had greater muscle content and lower dissected fat and bone than lambs. Kids had greater (P < 0.001) muscle ultimate pH value than lambs (5.8 +/- 0.02 vs. 5.6 +/- 0.02). Males had greater (P < 0.05) muscle ultimate pH value than females (5.7 +/- 0.02 vs. 5.6 +/- 0.02). The kid meat was significantly lighter (P < 0.05) and less yellow (P < 0.001) than the lamb meat. Kids presented less cooking losses (P < 0.001) than lambs, and shear force value was significantly greater (P < 0.01) in lamb meat. The kid meat had significantly more moisture (P < 0.001) and less intramuscular fat content (P < 0.001) than lambs. At this maturity stage, there were significant differences on both carcass and meat quality attributes of suckling kids and lambs, possibly due to inherent differences between species.

PI3K/Akt activation is critical for early hepatic regeneration after partial hepatectomy

Hepatic resection is associated with rapid proliferation and regeneration of the remnant liver. Phosphatidylinositol 3-kinase (PI3K), composed of a p85alpha regulatory and a p110alpha catalytic subunit, participates in multiple cellular processes, including cell growth and survival; however, the role of PI3K in liver regeneration has not been clearly delineated. In this study, we used the potent PI3K inhibitor wortmannin and small interfering RNA (siRNA) targeting the p85alpha and p110alpha subunits to determine whether total or selective PI3K inhibition would abrogate the proliferative response of the liver after partial hepatectomy in mice. Hepatic resection is associated with an induction in PI3K activity; total PI3K blockade with wortmannin and selective inhibition of p85alpha or p110alpha with siRNA resulted in a significant decrease in hepatocyte proliferation, especially at the earliest time points. Fewer macrophages and Kupffer cells were present in the regenerating liver of mice treated with wortmannin or siRNA to p85alpha or p110alpha, as reflected by a paucity of F4/80-positive cells. Additionally, PI3K inhibition led to an aberrant architecture in the regenerating hepatocytes characterized by vacuolization, lipid deposition, and glycogen accumulation; these changes were not noted in the sham livers. Our data demonstrate that PI3K/Akt pathway activation plays a critical role in the early regenerative response of the liver after resection; inhibition of this pathway markedly abrogates the normal hepatic regenerative response, most likely by inhibiting macrophage infiltration and cytokine elaboration and thus hepatocyte priming for replication.

Live weight and sex effects on carcass and meat quality of "Borrego terrincho-PDO" suckling lambs

Fifty seven suckling lambs (28 males and 29 females) of the Churra da Terra Quente breed were used to evaluate the effects of live weight and sex on carcass composition and meat quality traits. Lambs were slaughtered at three weight classes (<8kg, 8-11kg and >11kg) according to "Borrego Terrincho-PDO" specifications. The left sides of the carcasses were totally dissected. The longissimus thoracis and lumborum muscle was used for meat quality determination. Dressing proportion and carcass fatness were not affected by weight class or sex. Muscle proportion was similar in all carcass joints for the three weight classes. The percentage of bone decreased at the higher weight class, while that of subcutaneous and intermuscular fat increased. Female lambs had higher muscle proportions and greater muscle/bone ratios in the carcass side than males. Muscle pH, colour, cooking losses and tenderness were not affected by gender and weight class. Female lambs and weight classes 8-11kg and >11kg had higher proportions of intramuscular fat.

Prediction of carcase and breast weights and yields in broiler chickens using breast volume determinedin vivoby real-time ultrasonic measurement

1. The use of in vivo real-time ultrasonic (RTU) to predict breast and carcase weights and yields in 103 male broiler chickens was evaluated. Breast area (mm(2)), thickness (mm) and volume (cm(3)) were measured by RTU in three identified sites. After RTU measurements, the broiler chickens were weighed (live weight, LW, g) and slaughtered Carcase and breast weights (g) and physical measures of breast area (mm(2)), and thickness (mm) corresponding to the three identified sites, and volume (cm(3)) were recorded. 2. The best simple correlation between RTU and carcase measurements was obtained for breast volume. Breast and carcase weights were well predicted by LW. Furthermore, breast volume measured in carcase or by RTU was better in predicting breast weight and breast and carcase yields. 3. Multiple regression equations were fitted using LW (g) and RTU measurement of breast volume to predict breast and carcase weights and yields. The coefficients of determination were 0.52 and 0.65 for breast and carcase yields, respectively, and 0.92 and 0.99 for breast and carcase weights, respectively.

In vivo estimation of sheep carcass composition using real-time ultrasound with two probes of 5 and 7.5 MHz and image analysis1

Ultrasonic measurements were taken on 46 sheep using a real-time ultrasound machine equipped with 2 probes (5 and 7.5 MHz). Measurements of subcutaneous fat thickness (SC) and muscle LM depth (MD) and area (MA) were taken at 2 locations: over the 13th thoracic vertebra (SC13, MD13, and MA13, respectively) and at the interval between the third and fourth lumbar vertebrae (SC34, MD34, and MA34, respectively). Fat thickness was also measured over the third sternebra of the sternum. The relationship between carcass and in vivo ultrasound measurements was high for all the measurements (r(2) between 0.54 and 0.96, P < 0.01). Concerning MD and SC, the 7.5 MHz probe estimates were consistently more precise than the 5-MHz estimates (r(2) increased between 0.09 and 0.13), but the reverse occurred with the MA estimates, although to a lesser extent. Estimates of carcass composition for muscle, subcutaneous fat, intermuscular fat, internal fat, and total fat based on BW explained a large amount of variation in muscle (87%), subcutaneous fat (85%), intermuscular fat (79%), internal fat (74%), and total fat (87%). In most cases (55 of 70) the introduction of one ultrasound measurement in addition to BW in the multiple regression equations further improved the explanation of variation for weight of carcass tissues, internal fat, and total fat. For carcass muscle estimation, the ultrasound measurements of muscle provided an increase of r(2) between 0.05 and 0.10 (P < 0.01). The SC13 and SC34 gave the best improvements in estimating subcutaneous fat, intermuscular fat, internal fat, and total fat (r(2) increased between 0.05 and 0.17; P < 0.01). Prediction of the proportions of the carcass components (internal and total fat from BW) was clearly lower than the prediction of the absolute amounts of these traits. Inclusion of one or more ultrasound measurements in addition to BW increased the predictive ability of the equations. Both probes were useful to estimate carcass muscle depth and area and fat depth, but the 7.5-MHz probe showed a greater ability to estimate depth. For all traits, the stepwise procedure demonstrated that the best fit was obtained with BW and one or more ultrasound measurement with the 7.5-MHz probe.

Targeted molecular therapy of the PI3K pathway: therapeutic significance of PI3K subunit targeting in colorectal carcinoma

OBJECTIVE

The phosphatidylinositol 3-kinase (PI3K) pathway promotes cancer cell proliferation and survival. The authors determined the pattern of distribution of PI3K pathway components (ie, the p85alpha regulatory subunit, p110alpha catalytic subunit, Akt1, Akt2, and the tumor suppressor PTEN) in human colorectal cancer. In addition, inhibition of in vitro proliferation and in vivo liver metastasis by p85alpha or p110alpha siRNA treatment was analyzed.

SUMMARY BACKGROUND DATA

Small interfering RNA (siRNA) molecules suppress expression of target genes and may have therapeutic applications as target-specific therapies for cancer. Therefore, the purpose of this study was 2-fold: 1) to analyze the distribution pattern of PI3K pathway components in human normal colorectal cancers, and 2) to determine whether targeted inhibition of PI3K inhibits colon cancer growth in vitro and suppresses metastatic growth in vivo.

METHODS

Immunohistochemical analysis was performed on colorectal adenocarcinomas and adjacent normal mucosa for PI3K pathway components, including p85alpha, p110alpha, Akt1, Akt2, and the tumor suppressor PTEN, which inhibits PI3K. HT29 and KM20 human colon cancer cells were treated with siRNA directed to p85alpha or p110alpha, and cell viability and apoptosis assessed. HT29 cells, transfected with a plasmid containing green fluorescent protein (GFP), were injected into the spleen of athymic nude mice to establish liver metastases; mice were randomized to receive either nontargeting control (NTC), p85alpha or p110alpha siRNA.

RESULTS

PI3K pathway components p85alpha and Akt2 were highly expressed in glandular elements of colon cancers, with a correlation between staining intensity and clinical stage; PTEN expression was decreased in the colon cancers of all stages. PI3K-specific siRNA treatment decreased cell viability in vitro and suppressed metastatic tumor growth in vivo.

CONCLUSIONS

Selective targeting of PI3K pathway components may enhance the effects of standard chemotherapeutic agents and provide novel adjuvant treatment of selected colorectal cancers.

Antagonism of the acute hemodynamic effects of captopril in decompensated congestive heart failure by aspirin administration

The concomitant use of angiotensin-converting enzyme inhibitors and aspirin may cause pharmacological antagonism. Hence we examined the effect of aspirin on the neurohormonal function and hemodynamic response to captopril in heart failure patients. Between April 1999 and August 2000, 40 patients were randomized into four equal groups: 1) captopril, 2) aspirin, 3) captopril-aspirin: captopril was given alone on the first day, followed by aspirin on the remaining days, and 4) aspirin-captopril: aspirin was given alone on the first day, followed by captopril on the remaining days. Hemodynamic, norepinephrine and prostaglandin measurements were performed pre- and post-medication for 4 days. Captopril (50 mg) was given orally every 8 h and 300 mg aspirin was given on the first day, and 100 mg/day thereafter. In the captopril group and only on the first day of captopril-aspirin, captopril produced increases in cardiac index (2.1 +/- 0.6 to 2.5 +/- 0.5 l min-1 m-2, P<0.0001), and reduced peripheral vascular resistance (1980 +/- 580 to 1545 +/- 506 dyn s-1 cm-5/m , P<0.0001) and pulmonary wedge pressure (20 +/- 4 to 15 +/- 4 mmHg, P<0.0001). In contrast, aspirin alone or associated with captopril showed no significant hemodynamic changes. Norepinephrine decreased (P<0.02) only in the captopril group. Prostaglandin levels did not differ significantly among groups. Thus, aspirin compromises the short-term hemodynamic and neurohormonal effects of captopril in patients with acute decompensated heart failure.

Prenatal diagnosis of wormian bones

The prenatal diagnosis of wormian bones has not been made previously. We report four fetuses with wormian bones but none of the associated anomalies. The diagnosis, differential diagnosis, associated anomalies, and prognosis of this entity are discussed.

Fetal surgery for myelomeningocele and the incidence of shunt-dependent hydrocephalus

CONTEXT

Intrauterine closure of exposed spinal cord tissue prevents secondary neurologic injury in animals with a surgically created spinal defect; however, whether in utero repair of myelomeningocele improves neurologic outcome in infants with spina bifida is not known.

OBJECTIVE

To determine whether intrauterine repair of myelomeningocele improves patient outcomes compared with standard care.

DESIGN

Single-institution, nonrandomized observational study conducted between January 1990 and February 1999.

SETTING

Tertiary care medical center.

PARTICIPANTS

A sample of 29 study patients with isolated fetal myelomeningocele referred for intrauterine repair that was performed between 24 and 30 gestational weeks and 23 controls matched to cases for diagnosis, level of lesion, practice parameters, and calendar time. All infants were followed up for a minimum of 6 months after delivery.

MAIN OUTCOME MEASURES

Requirement for ventriculoperitoneal shunt placement, obstetrical complications, gestational age at delivery, and birth weight for study vs control subjects.

RESULTS

The requirement for ventriculoperitoneal shunt placement for decompression of hydrocephalus was significantly decreased among study infants (59% vs 91%; P = .01). The median age at shunt placement was also older among study infants (50 vs 5 days; P = .006). This may be explained by the reduced incidence of hindbrain herniation among study infants (38% vs 95%; P<.001). Following hysterotomy, study patients had an increased risk of oligohydramnios (48% vs 4%; P = .001) and admission to the hospital for preterm uterine contractions (50% vs 9%; P = .002). The estimated gestational age at delivery was earlier for study patients (33.2 vs 37.0 weeks; P<.001), and the birth weight of study neonates was less (2171 vs 3075 g; P<.001).

CONCLUSIONS

Our study suggests that intrauterine repair of myelomeningocele decreases the incidence of hindbrain herniation and shunt-dependent hydrocephalus in infants with spina bifida, but increases the incidence of premature delivery.

Nonlinear system identification using a neo fuzzy neuron algorithm: electrical drive application

This work presents a Neo-Fuzzy-Neuron algorithm for the identification of nonlinear dynamic systems at the point of view of a rotor flux observer. The algorithm training is on-line, has low computational cost, does not require previous training and its convergence in one step is proved. The gradient descent method is used for its weights adjustment. Simulation and experimental results demonstrate the effectiveness of the algorithm for flux observer of induction motor drive system.

Prenatal diagnosis of Down's syndrome in the presence of isolated Ebstein's anomaly

Ebstein's anomaly is a rare congenital cardiac defect, characterized by the displacement of the tricuspid valve into the right ventricle, that occurs approximately once in 20,000 live births. The association of Ebstein's anomaly and chromosomal abnormalities, such as Down's syndrome, is extremely unusual. Prenatal diagnosis of trisomy 21 in a fetus with isolated Ebstein's anomaly has not been previously reported.

Aortic reconstruction with crimped bovine pericardial conduits

BACKGROUND AND AIM OF THE STUDY

A bovine pericardial conduit processed in glutaraldehyde was designed, incorporating the principle of crimping used for synthetic vascular prostheses. The crimping process did not affect the integrity of collagen fibers and tissue structure. This conduit, designed for aortic reconstruction, is available in different sizes, with or without a biological valve.

METHODS

Between October 1989 and May 1997, 40 patients with aortic dissection, aortic aneurysm, aortic coarctation or aortoiliac occlusive disease underwent aortic reconstruction using this vascular substitute. Procedures included total reconstruction of the ascending aorta and aortic valve with reimplantation of coronary arteries (nine patients), single ascending thoracic aorta (six), descending thoracic aorta (two), aortic arch (one) and thoracoabdominal aorta (one); the abdominal aorta was reconstructed in 21 cases, including those undergoing aortoiliac or aortofemoral bypass.

RESULTS

The hospital mortality rate was 20% (eight patients); causes of deaths were low cardiac output, recurrence of aortic dissection, multiple organ failure and bleeding. Mean follow up was 3.6 years; total follow up was 114 patient-years. Late conduit-related complications occurred in four patients, including a limb obstruction in one patient subjected to aortofemoral bypass and infection of three resulting in pseudoaneurysm (incidence of 3.5 +/- 1.8% per patient-year). All underwent reoperation. There were four late deaths due to sudden death, coronary artery disease, pneumonia and metabolic complications of diabetes and renal failure (incidence of 3.5 +/- 1.8% per patient year). The eight-year actuarial survival rate was 63.7 +/- 11.6%, including hospital mortality, and the eight-year actuarial freedom from conduit failure due to primary tissue structural degeneration was 100%.

CONCLUSIONS

The crimping design provides a circular tube which makes construction of the anastomosis easier, retains its shape with bending, and avoids kinking. The material is very soft, easy to handle and suture, coapts nicely to suture lines resulting in a hemostatic anastomosis. The eight-year follow up demonstrated a satisfactory performance without report of fibrosis, calcification or aneurysmal dilation.

Evidence that 5-HT3 receptors in the nucleus tractus solitarius and other brainstem areas modulate the vagal bradycardia evoked by activation of the von Bezold-Jarisch reflex in the anesthetized rat

The effects of intracisternal (i.c.) application of the 5-HT3 receptor antagonist granisetron (0.016-0.16 microg kg-1) and the agonist phenylbiguanide (0.3-3 microg kg-1) on reflex bradycardia evoked by injection of phenylbiguanide (i.v.; 10 microg kg-1) were investigated in urethane anesthetized atenolol-pretreated rats. The effect of bilateral microinjection of granisetron (10 nmol per side, 100 nl) into the nucleus tractus solitarius (NTS) on the reflex was also investigated. Intracisternal administration of granisetron dose-dependently (0.016-0.16 microg kg-1) and significantly attenuated the reflex bradycardia whilst the highest dose given i.v. had no significant effect on the reflex bradycardia. Phenylbiguanide given i.c. only caused significant potentiation at the middle dose (1 microg kg-1), having no significant effects at the other doses. Neither granisetron nor phenylbiguanide given i.c. affected resting heart rate or blood pressure. Granisetron microinjected bilaterally into the NTS also significantly attenuated both reflex bradycardia and hypotension. It is concluded that excitation of cardiac vagal motoneurones evoked by cardiopulmonary afferents involves activation of 5-HT3 receptors located in the nucleus tractus solitarius and other brainstem areas.

Concentration of mercury in hair of indigenous mothers and infants from the Amazon basin

Hair mercury concentration, as an indicator of mercury body load, was studied in 251 samples of indigenous women and children living in selected areas of the Amazonian region. The mothers or women of child-bearing age, either non-Indians or Indians, and their children were sampled along the Madeira River and in the Kayapó reservation (Fresco River), respectively. Among the sampled individuals there were mothers with infants less than 2 years old. Total mercury in hair was determined by cold vapor atomic absorption spectrometry after alkaline digestion. The distribution of hair mercury concentration greater than 10 microg/g occurred in 67.4% of non-Indian women and 25% of Indian women; overall only 1% of non-Indian women had concentrations of hair mercury above 50 microg/g. In women of child-bearing age, the median and range of hair mercury concentration was 14.08 microg/g, and 0.8-94.7 microg/g for non-Indians, and 8.30 microg/g, and 0.8-13.3 microg/g for Indians. The correlation between maternal hair mercury and mercury in hair of infants (less than 2 years of age) still breast-feeding, was statistically significant only for non-Indians (r = 0.555 p < 0. 001). The correlation between length of breast-feeding and mercury concentration in infant's hair was significant for Indian children (r = 0.512; p = 0.029) but not for non-Indian children (r = 0.025; p = 0.832). A subsampling of 30 mothers had segmented hair analysis that showed a mean decrease of 20% in body burden during pregnancy, thus indicating the extent of placental transference of mercury to fetuses.

[Diagnostic value of exercise testing in the diagnosis of silent myocardial ischemia in elderly patients with systolic hypertension]

PURPOSE

To evaluate the diagnosis value of exercise testing for silent myocardial ischemia in systolic hypertension of the elderly.

METHODS

We compared 110 patients with systolic hypertension (group A) with 104 patients without hypertension (group B). They were submitted to an exercise test according to the Bruce protocol, between January/91 to December/94. Exercise was discontinued if target heart rate was achieved, or fatigue, dyspnea, severe arrhythmia, hypotension or significant ST segment depression > or = 2 mm/0.2 mV developed.

RESULTS

Exercise testing showed ischemic ST depression in 22 (20%) of the elderly patients with hypertension systolic and 12 (11.5%) of control elderly patients. The exercise time was shorter in the hypertensives 7.1 +/- 2.9 min vs 8.8 +/- 2.5 min. The ST depression was greater in the hypertensives than the control group: 2.5 +/- 0.8 min vs 1.9 +/- 0.4 min. Also the duration or ischemic ST depression was longer in the hypertensive patients than the control group 5.4 +/- 2.8 min vs 3.4 +/- 1.9 min.

CONCLUSION

Elderly hypertensive patients with systolic hypertension have more silent myocardial ischemia than elderly without hypertension. Among the elderly hypertensive patients there was a prevalence of silent ischemia that was 1.7 times higher than in the normotensive elderlies (20% vs 11.5% P < 0.003).

[Signs of myocardial ischemia associated with subarachnoid hemorrhage]

Electrocardiographic changes, left ventricular wall motion abnormalities, myocardial ischemia, myocytolysis and arrhythmias have been well documented in patients with cerebral bleed. These complications may be related to stimulation of autonomic nervous system and central nervous system. We report a case of a 38-year-old back woman without previous heart disease, taken to emergency unit with headache and subarachnoid Haemorrhage. One day after, she complained of retroesternal pain. An electrocardiographic tracing showed significant and diffuse ST-T wave abnormalities. The patient remained stable with no neurologic or cardiac deficits. She was treated with bed rest, nimodipine, isossorbide propranolol and is symptomless six months of follow-up.

[Acute myocardial infarction occurring in a young man due to crack use]

The relation between cocaine use and cardiovascular disease has been well documented including coronary artery vasoconstriction, coronary thrombosis, accelerated atherosclerosis, myocarditis, cardiomyopathies and endocarditis. Cocaine use has reached epidemic proportions. Cocaine is the most commonly abused drug among young patients. We report the case of a 32-year-old male admitted to the emergency department with myocardial infarction secondary to an overdose of cocaine.

Effects of losartan on neuroleptic-induced catalepsy in mice

Neuroleptic-induced catalepsy remains a useful method to study central dopaminergic function in rodents. Evidence obtained in several studies indicates that this phenomenon can be modified by cholinergic, histaminergic and serotonergic manipulation. Angiotensin II is a central neurotransmitter acting through AT1 and AT2 receptors. There are few data on the effect of angiotensinergic drugs on dopaminergic transmission. We investigated the effect of losartan, a nonpeptide antagonist of central and peripheral AT1 receptors, on neuroleptic-induced catalepsy. Adult male albino mice, 26-35 g, were used. Catalepsy was induced with haloperidol (H; 1 mg/kg, ip) and measured at 30-min intervals by means of a bar test. Losartan (10 or 100 ng/kg) or saline (control; 0.13 ml) was injected intraperitoneally 20 min before H, with each animal (7 per group) being used only once. Losartan (10 and 100 ng/kg) significantly (P < 0.05) potentiated the cataleptic effect of H in comparison to the control group (e.g. 264 +/- 26 and 299 +/- 68 sec, respectively, vs 89 +/- 24 sec for the control group, 90 min after H). No differences were demonstrable 120, 150 or 180 min after H. Considering the high selectivity and the pharmacokinetic properties of losartan, these data suggest that central angiotensin AT1 receptors play a role in neuroleptic-induced catalepsy. However, further studies are necessary to confirm this hypothesis and to clarify the mechanism(s) involved in this process.

[Arterial hypertension due to mercury intoxication with clinico-laboratorial syndrome simulating pheochromocytoma]

A 17 year-old boy was admitted to the hospital because of severe hypertension (200/130 mmHg), headache, irritability, and sweating. Initial biochemical tests suggested pheochromocytoma, being treated with nifedipine, clonidine and propranolol. However, with report of exposure to mercury vapor, twenty-four-hour urine screening and measurement of blood mercury confirmed intoxication. The patient underwent courses of chelation therapy with dimercaprol (BAL) and penicillamine with remission of symptoms and normalization of blood pressure after 2 months. This case has relevance for current practice reflecting similarity between mercury intoxication and hypertension secondary to pheochromocytoma.

Can caretakers of children with IDDM accurately measure small insulin doses and dose changes?

OBJECTIVE

To determine if caretakers of young children with IDDM could consistently reproduce small incremental measurements of insulin (U100).

RESEARCH DESIGN AND METHODS

Fifteen caretakers of children with IDDM were asked to deliver repeated small doses of insulin, including doses separated by only 0.25 U of insulin. A sensitive gravimetric technique was used to determine the error in measurement of these low doses of insulin. Statistical analysis was used to evaluate accuracy and internal consistency of each caretaker at each dose.

RESULTS

The means +/- SD at each dose level were as follows: 2.75 +/- 0.13 U at 2.5 U, 3.19 +/- 0.13 U at 3.0 U, 3.55 +/- 0.13 U at 3.25 U, and 3.70 +/- 0.11 U at 3.5 U. All doses were biased toward overadministration. There was as statistically significant difference in the dose delivered when the target doses were varied by only 0.25 U. The average differences and standard errors between 2.5 U and 3.0 U, 3.0 U and 3.25 U, and 3.25 U and 3.5 U were 0.44 +/- 0.20 U, 0.36 +/- 0.018 U, and 0.15 +/- 0.017 U, respectively.

CONCLUSIONS

Participants were not accurate in measuring small insulin doses, consistently overdrawing insulin by an average of 0.22 U. Caretakers are reasonably internally consistent with a given dose, since participants were able to measure statistically significant differences in 0.25 U dose changes. The error in insulin measurement does not vary with the intended dose level. Caretakers in the same family deliver insulin doses as variable from each other as they are from the population as a whole; however, when two or more individuals are responsible for one insulin dose in a child with IDDM, they have a combined variability that is approximately 40% greater than a single individual's variability.

[Arterial hypertension due to mercury intoxication with clinical and laboratorial syndrome simulating pheochromocytoma]

A 17-year-old boy was admitted to hospital because of severe hypertension (200/130 mmHg), headache, irritability, sweating, etc. Initial biochemical tests suggested pheochromocytoma, being treated with nifedipina, clonidina and propranolol. On reporting exposure to mercury vapour, he underwent twenty-four-hour urine screening and measurement of blood mercury which confirmed intoxication. The patient received courses of chelation therapy with dimercaprol (BAL) and penicillamine with remission of symptoms and normalisation of hypertension after 2 months. This case is relevant to current practice regarding similarity between mercury intoxication and hypertension secondary to pheochromocytoma.