Mapping genotypes to chromatin accessibility profiles in single cells

In somatic tissue differentiation, chromatin accessibility changes govern priming and precursor commitment towards cellular fates1-3. Therefore, somatic mutations are likely to alter chromatin accessibility patterns, as they disrupt differentiation topologies leading to abnormal clonal outgrowth. However, defining the impact of somatic mutations on the epigenome in human samples is challenging due to admixed mutated and wild-type cells. Here, to chart how somatic mutations disrupt epigenetic landscapes in human clonal outgrowths, we developed genotyping of targeted loci with single-cell chromatin accessibility (GoT-ChA). This high-throughput platform links genotypes to chromatin accessibility at single-cell resolution across thousands of cells within a single assay. We applied GoT-ChA to CD34+ cells from patients with myeloproliferative neoplasms with JAK2V617F-mutated haematopoiesis. Differential accessibility analysis between wild-type and JAK2V617F-mutant progenitors revealed both cell-intrinsic and cell-state-specific shifts within mutant haematopoietic precursors, including cell-intrinsic pro-inflammatory signatures in haematopoietic stem cells, and a distinct profibrotic inflammatory chromatin landscape in megakaryocytic progenitors. Integration of mitochondrial genome profiling and cell-surface protein expression measurement allowed expansion of genotyping onto DOGMA-seq through imputation, enabling single-cell capture of genotypes, chromatin accessibility, RNA expression and cell-surface protein expression. Collectively, we show that the JAK2V617F mutation leads to epigenetic rewiring in a cell-intrinsic and cell type-specific manner, influencing inflammation states and differentiation trajectories. We envision that GoT-ChA will empower broad future investigations of the critical link between somatic mutations and epigenetic alterations across clonal populations in malignant and non-malignant contexts.

Breast Cancer Macrophage Heterogeneity and Self-renewal are Determined by Spatial Localization

Tumor-infiltrating macrophages support critical steps in tumor progression, and their accumulation in the tumor microenvironment (TME) is associated with adverse outcomes and therapeutic resistance across human cancers. In the TME, macrophages adopt diverse phenotypic alterations, giving rise to heterogeneous immune activation states and induction of cell cycle. While the transcriptional profiles of these activation states are well-annotated across human cancers, the underlying signals that regulate macrophage heterogeneity and accumulation remain incompletely understood. Here, we leveraged a novel ex vivo organotypic TME (oTME) model of breast cancer, in vivo murine models, and human samples to map the determinants of functional heterogeneity of TME macrophages. We identified a subset of F4/80highSca-1+ self-renewing macrophages maintained by type-I interferon (IFN) signaling and requiring physical contact with cancer-associated fibroblasts. We discovered that the contact-dependent self-renewal of TME macrophages is mediated via Notch4, and its inhibition abrogated tumor growth of breast and ovarian carcinomas in vivo, as well as lung dissemination in a PDX model of triple-negative breast cancer (TNBC). Through spatial multi-omic profiling of protein markers and transcriptomes, we found that the localization of macrophages further dictates functionally distinct but reversible phenotypes, regardless of their ontogeny. Whereas immune-stimulatory macrophages (CD11C+CD86+) populated the tumor epithelial nests, the stroma-associated macrophages (SAMs) were proliferative, immunosuppressive (Sca-1+CD206+PD-L1+), resistant to CSF-1R depletion, and associated with worse patient outcomes. Notably, following cessation of CSF-1R depletion, macrophages rebounded primarily to the SAM phenotype, which was associated with accelerated growth of mammary tumors. Our work reveals the spatial determinants of macrophage heterogeneity in breast cancer and highlights the disruption of macrophage self-renewal as a potential new therapeutic strategy.

Integration of whole transcriptome spatial profiling with protein markers

Spatial transcriptomics and proteomics provide complementary information that independently transformed our understanding of complex biological processes. However, experimental integration of these modalities is limited. To overcome this, we developed Spatial PrOtein and Transcriptome Sequencing (SPOTS) for high-throughput simultaneous spatial transcriptomics and protein profiling. Compared with unimodal measurements, SPOTS substantially improves signal resolution and cell clustering and enhances the discovery power in differential gene expression analysis across tissue regions.

Single-cell multi-omics of human clonal hematopoiesis reveals that DNMT3A R882 mutations perturb early progenitor states through selective hypomethylation

Somatic mutations in cancer genes have been detected in clonal expansions across healthy human tissue, including in clonal hematopoiesis. However, because mutated and wild-type cells are admixed, we have limited ability to link genotypes with phenotypes. To overcome this limitation, we leveraged multi-modality single-cell sequencing, capturing genotype, transcriptomes and methylomes in progenitors from individuals with DNMT3A R882 mutated clonal hematopoiesis. DNMT3A mutations result in myeloid over lymphoid bias, and an expansion of immature myeloid progenitors primed toward megakaryocytic-erythroid fate, with dysregulated expression of lineage and leukemia stem cell markers. Mutated DNMT3A leads to preferential hypomethylation of polycomb repressive complex 2 targets and a specific CpG flanking motif. Notably, the hypomethylation motif is enriched in binding motifs of key hematopoietic transcription factors, serving as a potential mechanistic link between DNMT3A mutations and aberrant transcriptional phenotypes. Thus, single-cell multi-omics paves the road to defining the downstream consequences of mutations that drive clonal mosaicism.

931. Epidemiology and Clinical Outcomes of SARS-CoV-2 Infection Among Pediatric Solid Organ Transplant Recipients: A Single-Center Case Experience

Background

The impact of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection among pediatric solid organ transplant (SOT) recipients remains unclear. We sought to characterize the clinical epidemiology and outcomes following SARS-CoV-2 infection among pediatric SOT recipients in Dallas, TX.

Methods

Retrospective review of all SOT recipients with laboratory confirmed COVID-19 infection from March 1, 2020 –March 31, 2021. Demographic, clinical, and outcome data were stratified by transplant type and disease severity. Fischer’s exact test and Kruskall-Wallis test were used to evaluate risk factors for more severe disease among hospitalized children.

Results

Twenty-six SOT recipients with a median age of 14 years were included in the study. Fifteen (58%) were female, eighteen (69%) were Hispanic and thirteen (50%) were overweight/obese. Median time post-transplant was 3.6 years (1311 days, interquartile range (IQR) 394-2881). Fourteen patients were liver recipients, seven kidney, three heart, and two multiorgan. The majority of patients (65%) had a known community exposure and presented with fever (50%), cough (38%) and GI symptoms (19%). Half of all cases were hospitalized (n=13), with 2 requiring intensive care unit (ICU) admission, but no patients required positive pressure ventilation. Median hospital stay was 3 days. Five of the thirteen hospitalized patients were categorized as having moderate disease. No patients developed severe disease and there were no deaths. Older children, as well as children with multiple co-morbidities were noted on univariate analysis to be at higher risk for moderate, as compared to mild, disease.

Conclusion

SARS-CoV-2 infection among pediatric SOT recipients are at increased risk for hospital admission but demonstrate an overall mild /moderate disease course. Larger studies are required to elucidate the risk of morbidity between pediatric SOT recipients and immunocompetent children with SARS-CoV-2.

Disclosures

Amal Aqul, MD, Albireo pharma Inc. (Consultant)

Quinacrine as a potential treatment for COVID-19 virus infection

A novel coronavirus named severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a current outbreak of infection termed Coronavirus Disease 2019 (COVID-19) by the World Health Organization (WHO). COVID-19 is currently a global pandemic that may cause close to half a billion deaths around the world. Until now, there is no effective treatment for COVID-19. Quinacrine (Qx) has been used since the 1930s as preventive antimalarial compound. It is a recognized small molecule inhibitor of RNA virus replication, with known anti-prion activity, and identified as a potent Ebola virus inhibitor both in vitro and in vivo. Recently, Qx has showed anti-SARS-CoV-2 activity. Herein, we review the potential mechanisms associated with quinacrine as an antiviral compound.

Houston hurricane Harvey health (Houston-3H) study: assessment of allergic symptoms and stress after hurricane Harvey flooding

BACKGROUND

In August 2017, Hurricane Harvey caused unprecedented flooding across the greater Houston area. Given the potential for widespread flood-related exposures, including mold and sewage, and the emotional and mental toll caused by the flooding, we sought to evaluate the short- and long-term impact of flood-related exposures on the health of Houstonians. Our objectives were to assess the association of flood-related exposures with allergic symptoms and stress among Houston-area residents at two time points: within approximately 30 days (T1) and 12 months (T2) after Hurricane Harvey's landfall.

METHODS

The Houston Hurricane Harvey Health (Houston-3H) Study enrolled a total of 347 unique participants from four sites across Harris County at two times: within approximately 1-month of Harvey (T1, n = 206) and approximately 12-months after Harvey (T2, n = 266), including 125 individuals who participated at both time points. Using a self-administered questionnaire, participants reported details on demographics, flood-related exposures, and health outcomes, including allergic symptoms and stress.

RESULTS

The majority of participants reported hurricane-related flooding in their homes at T1 (79.1%) and T2 (87.2%) and experienced at least one allergic symptom after the hurricane (79.4% at T1 and 68.4% at T2). In general, flood-exposed individuals were at increased risk of upper respiratory tract allergic symptoms, reported at both the T1 and T2 time points, with exposures to dirty water and mold associated with increased risk of multiple allergic symptoms. The mean stress score of study participants at T1 was 8.0 ± 2.1 and at T2, 5.1 ± 3.2, on a 0-10 scale. Participants who experienced specific flood-related exposures reported higher stress scores when compared with their counterparts, especially 1 year after Harvey. Also, a supplementary paired-samples analysis showed that reports of wheezing, shortness of breath, and skin rash did not change between T1 and T2, though other conditions were less commonly reported at T2.

CONCLUSION

These initial Houston-3H findings demonstrate that flooding experiences that occurred as a consequence of Hurricane Harvey had lasting impacts on the health of Houstonians up to 1 year after the hurricane.

P588Flow profile for a better non-invasive pressure drop in CoA

Introduction

In cardiovascular obstructions, as Coarctation of the Aorta (CoA), guidelines recommend treatment based on a relevant pressure drop (ΔP). Diagnostic ΔP is estimated by simplified Bernoulli (SB) and is measured as peak-to-peak (PtP) ΔP via catheterization. The divergences amid methods are understood, but it is common practice to widely and positively accept both as valid diagnostic. Recently, simplified advective work-energy relative pressure (SAW) to correct SB by considering the full velocity profile for the ΔP computation.

Purpose

To verify the correctness of peak flow derived pressure drop via maximal velocity (SB), and full flow profile (SAW) versus clinical gold-standard PtP ΔP in a CoA phantom.

Methods

An MRI-compatible and pulsatile CoA phantom was built and tested in eight configurations, with four levels of obstruction (9, 11 and 13 mm CoA diameter and no CoA) under two flow regimes (stress and normal). The ΔP was measured via catheterization between ascending and in descending aorta (DA) as instantaneous and as PtP. Also, MRI 4D-flow velocity vector fields were acquired, enabling the ΔP estimation by SB and SAW at effective orifice area (EOA) and DA catheterization locations. at the point of the effective orifice area (EOA) and at DA catheterization location.

Results

The disparity in ΔP illustrate the fundamental differences between methods (figure and table). Catheterised instant and PtP ΔPs are similar for the CoA phantom configurations, where SB and SAW are valid. The lesser the obstruction, the greater is the temporal acceleration contribution to the ΔP and discrepancies between methods arise. As recognised, SB is an overestimation of the catheterization measurements. The most equivalent ΔPs are the catheterization PtP and SAW. Velocity-based ΔPs (SB and SAW) show a drop in performance when the velocity is captured at the DA instead of the right EOA point, illustrating the sensitivity to the acquisition location.

Peak ΔPs per method and per phantom 9mm CoA 11mm CoA 13mm CoA Normal R2 Linear eq. rest stress rest stress rest stress rest stress Instant ΔP 33.4 45.7 11.5 19.6 12.1 14.5 −2.7 −12.2 0.949 y=1.12x PtP ΔP 29.3 43.5 10.0 16.0 5.8 11.2 −1.8 -3.6 – – SB EOA 37.5 52.3 13.4 22.3 6.1 11.4 1.4 1.4 0.988 y=1.23x SB DA 22.6 59.8 10.7 18.6 5.2 8.5 0.9 1.2 0.893 y=1.15x SAW EOA 29.9 51.4 11.3 19.0 4.9 9.7 0.8 0.8 0.972 y=1.11x SAW DA 11.74 28.3 5.5 9.9 2.7 4.5 0.6 0.7 0.911 y=0.56x Linear comparisons were made against gold-standard catheterised PtP ΔP.

Velocity meshes and ΔPs in cardiac cycle

Conclusions

Initial phantom evidence suggests that the non-invasive ΔP assessments based on flow should consider the full flow profile and be acquired at the point of EOA.

Acknowledgement/Funding

PIC project, European Union's Horizon 2020 Marie Skłodowska-Curie ITN Project under grant agreement No 764738

Abstract P3-03-01: Clinical utility of finding pathogenic mutations beyond BRCA1/2 in breast cancer patients

Background

The clinical utility of germline genetic testing for BRCA1 and BRCA2 has long been established. However, management recommendations for pathogenic variants in other genes, typically included in multigene panels, have only recently been included in consensus guidelines for HBOC. The clinician actions implemented for findings in these genes, and patient follow-up, are not yet well studied. We report interim results from a multi-site study of clinical actions undertaken in patients presenting with HBOC and carrying a pathogenic germline mutation in cancer risk genes other than BRCA1/2.

Methods

We retrospectively examined a cohort of patients with a personal history of HBOC who had been referred for hereditary cancer multigene testing from three major academic medical centers. For patients with pathogenic findings in a non-BRCA1/2 cancer risk gene, ordering clinicians completed a short case report form describing the clinical actions taken in response to the genetic test result, and patient follow-up. Some patients were lost to follow-up and answers of “unknown” were permitted. Genes with positive findings included CHEK2, PALB2, ATM, MUTYH, RAD51C, TP53, MSH6, RAD50, APC, BARD1, BRIP1, MSH2, NF1, NBN, PMS2, and PTEN. Case report forms were available for 77 patients as of our cut off date, and these data were de-identified and summarized for this interim report. Additional cases continue to accrue in this ongoing study.

Results

In 57% (44/77) of cases, clinicians reported that counseling and/or clinical management recommendations were changed in response to the genetic test findings. Management changes included modification of imaging surveillance (38%), considered or recommended surgical prophylaxis (12%), modified surgical plan for an existing malignancy (5%), and for one patient each: inclusion in a research trial for PARP inhibitors, modification of colonoscopy schedule, and screening for cancers other than existing malignancy. Clinicians indicated that genetic test results changed management in 48% of patients, did not change management in 29%, and had unknown impact for 23%.

Clinicians also reported that counseling and/or management for the patients' family members was changed in 67% (52/77) of cases, including family variant testing. 27% (21/77) of the patient families had cascade genetic testing, and one or more new carriers were identified in 47% (10) of the tested families. In 58% of cases, the impact of management recommendations on family members was unknown as of the case report date.

Conclusions

Pathogenic variants in non-BRCA genes are present in about 3-11% of patients with a history of HBOC. This study suggests that genetic test results in cancer genes beyond BRCA1/2 changed clinical management for a majority of patients and their family members, led to identification of new carriers, and directly impacted treatment decisions. In almost half of these patients, genetic test results impacted their health outcome, including those reported to be disease free after undergoing interventional or prophylactic surgery informed by their genetic variant. More research is needed to improve the implementation of genetic testing based management recommendations for patients and their family members.

Citation Format: Esplin ED, Michalski S, Yang S, Hampel H, Jeter J, Sweet K, Pilarski R, Pearlman R, Shane K, Brock P, Westman J, Chittenden A, Stopfer J, Schneider K, Sacca R, Stickevers S, Kipnis L, Koeller D, Gaonkar S, Sotelo J, Vaccari E, Cochrane S, Champine M, Espinel W, Lincoln SE, Nussbaum RL. Clinical utility of finding pathogenic mutations beyond BRCA1/2 in breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-03-01.

Focal Plane Shift Imaging for the Analysis of Dynamic Wetting Processes

Droplet-surface interactions are common to a plethora of natural and industrial processes due to their ability to rapidly exchange energy, mass, and momentum. Droplets are particularly of interest due to their large surface-to-volume ratios and hence enhanced transport properties. For example, coalescence-induced droplet jumping on superhydrophobic surfaces has recently received much attention for its potential to enhance heat transfer, anti-icing, and self-cleaning performance by passively shedding microscale water droplets. To study droplet jumping, researchers typically use a two-camera setup to observe the out-of-plane droplet motion, with limited success due to the inability to resolve the depth dimension using two orthogonal cameras. Here we develop a single-camera technique capable of providing three-dimensional (3D) information through the use of focal plane manipulation, termed "focal plane shift imaging" (FPSI). We used FPSI to study the jumping process on superhydrophobic surfaces having a wide range of structure length scales (10 nm < l < 1 μm) and droplet radii (3 μm < R < 160 μm). We benchmarked the FPSI technique and studied the effects of droplet mismatch, multidroplet coalescence, and multihop coalescence on droplet jumping speed. Furthermore, we were able to resolve the full 3D trajectory of multiple jumping events, to show that, unlike previously theorized, the departure angle during droplet jumping is not a function of droplet mismatch or number of droplets coalescing prior to jumping. Rather, angular deviation arises due to in-plane motion postcoalescence governed by droplet pinning. The outcomes of this work both elucidate key fundamental aspects governing droplet jumping and provide a powerful imaging platform for the study of dynamic droplet processes that result in out-of-plane motion such as sliding, coalescence, or impact.

Mechanical properties of zeolitic metal–organic frameworks: mechanically flexible topologies and stabilization against structural collapse

We report the low elastic modulus of a zeolitic MOF, along with stabilization against structural collapse by filling with solvent.

Neurocysticercosis: relationship between the developmental stage of metacestode present and the titre of specific IgG in the cerebrospinal fluid

In double-blind, immunological assays, samples of cerebrospinal fluid (CSF) from 141 patients with neurocysticercosis (NCC) or other neurological disorders were tested for IgG reacting with the excretory/secretory (E/S) antigens of Taenia solium metacestodes. The results for the cases of NCC were then correlated with the developmental stage of the metacestodes present in each case, as assessed by computerized tomography and magnetic-resonance imaging. In the ELISA first used, the samples of CSF from most (88%) of the patients with the vesicular stage of NCC (some of whom also had the degenerate and/or calcified metacestodes) were found to contain the specific IgG. In electro-immunotransfer blot (EITB) assays, three of the E/S antigens, of 95, 49 and 29 kDA, were recognized by 86%-100% of the ELISA-positive CSF. When these three antigens were isolated and tested, as a pool, against all the CSF samples in double-blind ELISA, almost all (96.6%) of the CSF samples from patients with metacestodes at the vesicular stage were recognized. In the detection of individuals with vesicular metacestodes, the assay based on the three isolated antigens was significantly more sensitive than that based on the crude extract of E/S antigens (P < 0.05). In EITB assays based on the three antigens, the isolated proteins were again recognized by IgG in the CSF samples from those with vesicular metacestodes, but without the background 'noise' seen with the crude extract. In every assay employed, none of the CSF samples from NCC cases who only harboured degenerative and/or calcified metacestodes and none of those from patients who had other neurological disorders gave a positive result. The use in ELISA and EITB of antigens purified from crude extracts of metacestode E/S proteins could improve the immunodiagnosis of the vesicular stage of NCC, and allow better evaluation of NCC cases both pre- and post-treatment.

The antimalarials quinacrine and chloroquine potentiate the transplacental carcinogenic effect of ethylnitrosourea on ependymal cells

Quinacrine and chloroquine, two widely used antimalarials, bind strongly to deoxyribonucleic acid, thus preventing mutagenesis. We studied a possible chemoprotective effect of these substances on carcinogenesis of the nervous system induced in Wistar rats by transplacental administration of ethylnitrosourea. One experimental group consisted of rats born from mothers treated with quinacrine prior to prenatal exposure to ethylnitrosourea; a second group consisted of rats chronically treated with chloroquine after prenatal exposure to ethylnitrosourea. When compared with controls, no significant differences were observed in tumor incidence. However, early tumor growth was observed in both rats treated with quinacrine (P < 0.0004) and rats treated with chloroquine (P < 0.02). These differences were due mostly to rapid development of ependymomas of the spinal cord. Our results suggest that quinacrine and chloroquine do not prevent the structural alterations induced in DNA by ethylnitrosourea, which lead, in the long term, to a high incidence of neoplasms in the nervous system. Moreover, the antimalarials studied seem to promote the carcinogenic effects of ethylnitrosourea on ependymal cells.

Retinoic acid reduces chemotherapy-induced neuropathy in an animal model and patients with lung cancer

OBJECTIVE

To evaluate the effect of all-trans retinoic acid (ATRA) as treatment for chemotherapy-induced peripheral neuropathy in an experimental animal model and in a randomized, double-blinded, controlled trial in patients with non-small-cell lung cancer (NSCLC).

METHODS

Forty male Wistar rats were randomized in 5 groups: group A, control; groups B and C, treated with cisplatin; and groups D and E, treated with paclitaxel. ATRA (20 mg/kg PO) was administered for 15 days in groups C and E. We evaluated neuropathy and nerve regeneration-related morphologic changes in sciatic nerve, the concentration of nerve growth factor (NGF), and retinoic acid receptor (RAR)-α and RAR-β expression. In addition, 95 patients with NSCLC under chemotherapy treatment were randomized to either ATRA (20 mg/m(2)/d) or placebo. Serum NGF, neurophysiologic tests, and clinical neurotoxicity were assessed.

RESULTS

The experimental animals developed neuropathy and axonal degeneration, associated with decreased NGF levels in peripheral nerves. Treatment with ATRA reversed sensorial changes and nerve morphology; this was associated with increased NGF levels and RAR-β expression. Patients treated with chemotherapy had clinical neuropathy and axonal loss assessed by neurophysiology, which was related to decreased NGF levels. ATRA reduced axonal degeneration demonstrated by nerve conduction velocity and clinical manifestations of neuropathy grades ≥2.

CONCLUSIONS

ATRA reduced chemotherapy-induced experimental neuropathy, increased NGF levels, and induced RAR-β expression in nerve. In patients, reduction of NGF in serum was associated with the severity of neuropathy; ATRA treatment reduced the electrophysiologic alterations.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that ATRA improves nerve conduction in patients with chemotherapy-induced peripheral neuropathy.

Paclitaxel and cisplatin versus paclitaxel and cisplatin plus all-trans retinoic acid for the prevention of chemotherapy-induced neuropathy: A randomized phase II trial

e14506

Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a common adverse event, similar to that of diabetes where there is reduction of the expression and transport of Neural Growth Factor (NGF). Retinoic acid regulates genes related to cellular proliferation and NGF expression. We conducted this clinical trial to determine the effect of all-trans retinoic acid (ATRA) on the development of CIPN with paclitaxel and cisplatin in patients with advanced non-small cell lung cancer (NSCLC). Methods: Ninety five patients with advanced NSCLC were included to receive chemotherapy based on paclitaxel 175 mg/m2 and cisplatin 80 mg/m2 every 3 weeks for a maximum of 6 cycles. The patients were randomized to receive ATRA 20 mg/day or placebo 1 week before treatment until after completing 2 cycles. Prior to chemotherapy and after 2 cycles of treatment neurophysiology tests, clinical exam and serum NGF levels (34 patients) were performed. Results: There were no differences in general characteristics of the patients between groups. NGF serum levels were lower in the placebo group 4.89 pg/ml baseline and 4.6 pg/ml 2C (p = 0.007) versus ATRA 4.8 pg/ml and 4.7 pg/ml (p=0.107). The electrophysiological studies showed a greater degree of motor axonal damage in the right (p=0.003) and left (p=0.013) tibial nerves in the placebo group after 2C. In the ATRA group there were no significant differences baseline and after chemotherapy. Conclusions: ATRA might have a neuroprotective effect in patients with NSCLC treated with paclitaxel and cisplatin. A phase III trial is needed to confirm these findings.

No significant financial relationships to disclose.

Angiogenesis and expression of estrogen and progesterone receptors as predictive factors of recurrence in meningiomas: A long-term prospective study

e13013

Background: Meningioma is a bening tumor, with a high rate of recurrence after surgery (80%); the most important relapse predictive factor is the extent of surgical resection; other potentially predictive factors have been studied with poor results. Angiogenesis has an important role in growth and spread of neoplasic cells; previous studies have shown a high incidence of cyclin E (CE), estrogen, and progesterone receptors (ER, PR) in meningiomas. The aim of this prospective study was to evaluate the prognostic significance of clinical-pathological factors (CPF), vascular density index (VDI), cell proliferation index (CPI), CE, ER, and PR tissue expression in meningioma recurrence of patients submitted to surgical resection. Methods: From January 1995 to December 2000, we enrolled 42 patients with histopathological diagnosis of meningioma and treated only with surgical resection. Tumor VDI, CPI, CE, ER, and PR tissue expression were evaluated by immunohistochemistry in patients with or without recurrence. CPF, VDI, CPI, and expression of CE, ER, and PR were associated with recurrence. Results: Complete surgical resection was achieved in 32.5% of patients. Minimal follow-up was 6 years. Recurrence of meningioma was found in 17 patients (40%). Mean time of recurrence was 32 + 8 months. Tissue expression was positive for CE, ER, and PR in 90.9%, 27.6%, and in 64% of patients, respectively. VDI was >8 (40X in 10 fields) in 52.6% of patients and CPI was >600 (40X in 10 fields) in 54.2% of patients. Significant recurrence-associated factors were extent of resection (RR = 2.4, 95% CI 1.7–2.9, p = 0.03) and VDI >8 (RR = 1.7, 95% CI 1.003–2.9, p = 0.001). CPI, CE, ER, and PR expressions were not statistically significant (p = 0.83, p = 0.16, p = 0.46, and p = 0.74, respectively). Conclusions: Patients with partially resected meningioma and high VDI have an increased recurrence risk and could benefit of additional therapeutic measures.

No significant financial relationships to disclose.

Pt/TiO2 brain biocompatible nanoparticles: GBM treatment using the C6 model in Wistar rats

In the present work we synthesized inorganic oxide nanoparticle carriers of platinum compounds and tested their therapeutic effect on animal models in which C6 glioma cells have been inoculated. TiO(2)-containing Pt(NH(3))(4)Cl(2) complexes were synthesized using sol-gel methods. The platinum species are chemically bonded to the TiO(2) carrier, as shown by Fourier transform infrared spectroscopy of probe molecules. Treatment with TiO(2)-Pt nanoparticles reduces tumour growth rate by up to 56%, showing that a synergistic effect exists between the TiO(2) carrier and the platinum drug.

Expression of AT1 and AT2 angiotensin receptors in astrocytomas is associated with poor prognosis

Astrocytomas develop intense vascular proliferation, essential for tumour growth and invasiveness. Angiotensin II (ANGII) was initially described as a vasoconstrictor; recent studies have shown its participation in cellular proliferation, vascularisation, and apoptosis. We conducted a prospective study to evaluate the expression of ANGII receptors – AT1 and AT2 – and their relationship with prognosis. We studied 133 tumours from patients with diagnosis of astrocytoma who underwent surgery from 1997 to 2002. AT1 and AT2 were expressed in 52 and 44% of the tumours, respectively, when determined by both reverse transcriptase–polymerase chain reaction and immunohistochemistry. Ten per cent of low-grade astrocytomas were positive for AT1, whereas grade III and IV astrocytomas were positive in 67% (P<0.001). AT2 receptors were positive in 17% of low-grade astrocytomas and in 53% of high-grade astrocytomas (P=0.01). AT1-positive tumours showed higher cellular proliferation and vascular density. Patients with AT1-positive tumours had a lower survival rate than those with AT1-negative (P<0.001). No association to survival was found for AT2 in the multivariate analysis. Expression of AT1 and AT2 is associated with high grade of malignancy, increased cellular proliferation, and angiogenesis, and is thus related to poor prognosis. These findings suggest that ANGII receptors might be potential therapeutic targets for high-grade astrocytomas.

Chronic malnutrition does not influence the development of ethylnitrosourea-induced brain tumors

There is controversy over the subject of malnutrition as a potential risk factor for cancer; we studied the effect of chronic malnutrition on the development of tumors in rats prenatally exposed to the carcinogenic ethylnitrosourea. Twelve pregnant Wistar rats were administered on the 19th day of gestation with a single i.v. dose of 30 mg/kg of ethylnitrosourea. Immediately after weaning, at 23 days of age, half of the offspring were nourished with a protein-deficient diet (less than 6%), which consisted mostly of a corn-based diet with high calorie and low fiber contents. In the adult age, 83 rats (74%) developed a tumor of the nervous system; in comparison with controls, we found no differences in time of development, site and histological characteristics of the tumors that developed in animals subjected to chronic malnutrition.

Frequent association of multiple sclerosis with varicella and zoster

BACKGROUND

A possible association of multiple sclerosis (MS) with viral diseases has been postulated; in previous studies we have found that in Mexican mestizos the antecedent of varicella during childhood represents a risk factor for the development of MS during adulthood.

AIM

We conducted a retrospective search for varicella and zoster infections associated with the development of MS.

METHODS AND RESULTS

In a cohort of 82 consecutive patients with MS we found six cases, four of varicella and two of zoster, that were concurrent with the development or the progress of MS.

CONCLUSIONS

The association of these pathologies is higher than expected and suggests a possible etiological relationship of the varicella zoster virus with MS.

Blockage of angiotensin II type I receptor decreases the synthesis of growth factors and induces apoptosis in C6 cultured cells and C6 rat glioma

Angiotensin II (Ang II) is a main effector peptide in the renin–angiotensin system and participates in the regulation of vascular tone. It also has a role in the expression of growth factors that induce neovascularisation which is closely associated to the growth of malignant gliomas. We have shown that the selective blockage of the AT₁ receptor of angiotensin inhibites tumour growth, cell proliferation and angiogenesis of C6 rat glioma. The aim of this study was to study the effects of the blockage of AT₁ receptor on the synthesis of growth factors, and in the genesis of apoptosis in cultured C6 glioma cells and in rats with C6 glioma. Administration of losartan at doses of 40 or 80 mg kg⁻¹ to rats with C6 glioma significantly decreased tumoral volume and production of platelet-derived growth factor, vascular endothelial growth factor and basic fibroblast growth factor. It also induced apoptosis in a dose-dependent manner. Administration of Ang II increased cell proliferation of cultured C6 cells which decreased by the administration of losartan. Our results suggest that the selective blockage of AT₁ diminishes tumoral growth through inhibition of growth factors and promotion of apoptosis.

Retinoic acid increases tissue and plasma contents of nerve growth factor and prevents neuropathy in diabetic mice

BACKGROUND

Decreased production of nerve growth factor (NGF) may contribute to diabetic neuropathy; however, exogenous administration of NGF induces only a modest benefit. Retinoic acid (RA) promotes the endogenous expression of nerve growth factor and its receptor. We studied the effects of RA on diabetic neuropathy in mice with streptozotocin-induced diabetes.

MATERIAL AND METHODS

One hundred and twenty National Institutes of Health (NIH) albino mice randomly separated into three groups (A, n = 30; B, n = 30; C, n = 60). Diabetes mellitus was induced with streptozotocin in groups A and B. Animals from group A received a subcutaneous injection of 25 microl of mineral oil daily for 90 days, while those from group B received a subcutaneous injection of 20 mg kg(-1) of all trans RA. Animals from group C were taken as controls. At the end of the experiment, blood glucose and NGF levels (both in serum and sciatic nerve) were measured. Two behavioural tests were conducted in a blind fashion to detect abnormalities of thermal and nociceptive thresholds.

RESULTS

Contents of NGF in healthy untreated mice were 1490 +/- 190 pg mg(-1) in nerve and 113 +/- 67 pg mg(-1) in serum; in diabetic untreated mice the values were 697 +/- 219 pg mL(-1) in nerve and 55 +/- 41 pg mL(-1) in serum; and in diabetic mice treated with RA the values were 2432 +/- 80 pg mL(-1) in nerve and 235 +/- 133 pg mg(-1) in serum (P < 0.002). Ultrastructural evidence of nerve regeneration and sensitivity tests improved in diabetic mice treated with RA as compared with nontreated diabetic mice.

CONCLUSION

Our findings indicate that administration of RA increases serum and nerve contents of NGF in diabetic mice and suggest a potential therapeutic role for retinoic acid in diabetic patients.

Relationship between maize stem structural characteristics and resistance to pink stem borer (Lepidoptera: Noctuidae) attack

The pink stem borer, Sesamia nonagrioides (Lefebvre), is one of the most important insect pests of maize (Zea mays L.) in northwestern Spain. The objectives of this work were to evaluate, at different times during the growth of maize, structural traits related to the entry point and tissues on which larvae feed and to determine the relationship between these structural traits and the stem borer resistance. Six inbred lines with different levels of stem resistance to S. nonagrioides were evaluated in several trials. Potential structural resistance factors included rind and pith puncture resistance (RPR and PPR), rind thickness, length of the meristematic area (LMA), and pith parenchyma interlumen thickness (PPIT). Surprisingly, the inbred lines that showed the strongest stalks, EP42 and EP47, were not stem resistant to pink stem borer attack, while the stem resistant inbreds A509, CM151, and PB130 were among the least resistant to rind puncture. There were no significant differences among resistant and susceptible inbreds for the rind thickness. However, the susceptible inbred EP42 had the softest internode pith, and the resistant inbred PB130 showed the hardest, as was expected. Susceptible inbred lines in general showed higher values for the LMA, while the PPIT was important for individual inbreds. The results suggest that the usefulness of these characters as estimators of pink stem borer resistance is limited to some genotypes. Besides, even among those genotypes, other mechanisms of resistance that do not involve stalk strength could be present. Among the traits considered, the LMA was the most promising as an indicator of resistance to pink stem borer, although further experimentation is necessary.

Sensitivity and specificity of ELISA and immunoblot for diagnosing neurocysticercosis

In patients with neurocysticercosis (NCC), clinical manifestations and the results of neuroimaging procedures vary widely and often do not facilitate a definite diagnosis. In order to determine the value of immunodiagnosis for NCC, 222 serum and cerebrospinal fluid samples from patients with NCC and healthy subjects were examined. The samples represented patients from various endemic regions, those with other neurological disorders from an endemic area (Mexico), persons with various helminth infections other than NCC, and a group of healthy volunteers. All specimens were tested by enzyme-linked immunosorbent assay and immunoblot for the presence of Taenia solium-specific antibodies. The sensitivities of the enzyme-linked immunosorbent assay and the immunoblot test in NCC patients were almost identical (80% and 81.7%, respectively). For both tests, the sensitivity was higher when cerebrospinal fluid (86%) was tested compared with serum (75%). The overall specificity of enzyme-linked immunosorbent assay was only 75.3% because of frequent false-positive results in patients with other helminth infections, especially in those with echinococcosis. The specificity (99.4%) of the immunoblot test was clearly superior. It is concluded that enzyme-linked immunosorbent assay as a screening method and immunoblot as a confirmatory test contribute considerably to the diagnosis of NCC.

Varicella, ephemeral breastfeeding and eczema as risk factors for multiple sclerosis in Mexicans

OBJECTIVE

It has been suggested that the incidence of multiple sclerosis (MS) in Mexico and other countries of Latin America has increased steadily for the last two decades. We made a thorough search of antecedents on MS patients that could be potential risk factors.

METHODS

A case-control study was conducted using a questionnaire that included demographic, nutritional, infectious and personal antecedents previously identified in other reports as possible risk factors for MS.

RESULTS

The frequency of varicella, ephemeral breastfeeding and eczema in the medical history of MS patients were significant when compared with controls; all appeared to be mutually additive. However, they were unrelated with clinical characteristics or disease severity.

CONCLUSION

During the last decades, breastfeeding has been abandoned in large segments of society and the incidence of varicella and childhood eczema keeps a north-south gradient similar to that described for MS. These factors may participate in the sharp increase of MS in countries like Mexico traditionally considered as an area of very low incidence.

AT1 receptor is present in glioma cells; its blockage reduces the growth of rat glioma

Malignancy of neoplasms is partly dependent on angiogenesis. Angiotensin II mediates angiogenesis and transcription of growth-related factors through stimulation of the AT1 receptor (AT1R). Losartan, a drug used mostly for treatment of hypertension, binds strongly to this receptor. We found the presence of AT1 receptor on C6 glioma cells and studied the effect of Losartan on the growth and angiogenesis of C6 rat glioma; Losartan in dose of 80 mg/kg induced 79% reduction of tumoural volume with a significant decrease of vascular density, mitotic index and cell proliferation. Our results demonstrate the conspicuous presence of AT1R in malignant glial cells and a favourable therapeutic response in experimental glioma by selective blockage of the AT1 receptor.

Clomipramine increases the striatal concentrations of dopamine and homovanillic acid in rats chronically consuming alcohol

OBJECTIVE

There have been many studies on the relationships between the dopaminergic system, alcoholism and antidepressant drugs; the information, however, is controversial. The purpose of this study was to examine the effect of clomipramine (CMI), a tricyclic antidepressant, on the striatal concentration of dopamine (DA) and homovanillic acid (HVA), and their turnover, in a rat model of chronic alcohol ingestion.

METHOD

After 10 months of exposure to either water (expW) or alcohol (expA), female Wistar rats (N = 60) were randomly assigned to one of the following six groups: (1) (expW) control group (C), normal diet; (2) (expA) alcohol administration group (A), drinking water was replaced by commercial brandy that was 38% ethanol; (3) (expW) clomipramine group (CMI), received intraperitoneal injections over 4 months; (4) (expA) alcohol administration + clomipramine group (ACMI); (5) (expA) alcohol abstinence group (AA); and (6) (expA) alcohol abstinence + clomipramine group (AACMI). Each group consisted of 10 animals.

RESULTS

Chronic alcohol intake decreased striatal dopamine concentration (p < .001), whereas clomipramine administration produced a significant increase (p < .001) when administered in both control rats and rats exposed to long-term alcohol administration. The increase in the ACMI group was significantly different (p < .001) when it was compared with the CMI group. In the AA and AACMI groups, a significant decrease of striatal dopamine was observed (p < .001). During long-term alcohol administration, homovanillic acid decreased (p < .005). HVA/DA ratio increased in AA and AACMI groups (p < .001).

CONCLUSIONS

These findings show that clomipramine produces favorable changes in dopaminergic systems altered by chronic alcohol administration. Results also provide evidence to support further prospective studies of potential therapeutic effects of antidepressant drugs in alcoholism.

Paradoxical effect of aspirin on the growth of C6 rat glioma and on time of development of ENU-induced tumors of the nervous system

PURPOSE

Administration of acetylsalicylic acid (ASA), an inhibitor of the synthesis of prostaglandins and thrombzoxanes, decreases the incidence of colorectal cancer and other neoplasms and inhibits in vitro some tumor growth. We studied the effect of various doses of ASA on the growth of C6 glioma implanted in rats as well as the effect of chronic administration of ASA on time of development and incidence of tumors of the central nervous system (CNS) induced by prenatal exposure to ethylnitrosourea (ENU).

METHODS

In a controlled study, various doses of ASA, 12.5, 25, 50, 100, 200, 300, and 400 mg/kg per day, were administered to Wistar rats in whom a subcutaneous C6 glioma had been transplanted. Changes in tumor size, histologic characteristics, mitotic index, cell proliferation, and vascular density were studied. In a parallel experiment, we administered ASA (70 mg/kg per day) to rats who were prenatally exposed to ENU; treatment started on day 50 of age, and continued until the end of the experiment at day 400. The time of tumor development as well as incidence, localization, and histological diagnosis were compared with matched controls.

RESULTS

A paradoxical effect of ASA administration was observed on the dynamics of cell proliferation of C6 glioma. When high ASA doses were administered (200 or 400 mg/kg per day), tumor volume, cell proliferation, vascular density, and mitotic index increased. In contrast, when low doses were administered (12.5 or 25 mg/kg per day) the tumor size diminished. In the second experiment, localization and incidence of CNS tumors induced by ENU were similar in animals treated with ASA and in controls; however, in rats treated with ASA the time of tumor development was shortened.

CONCLUSIONS

The growth-promoting effects of high doses of ASA found in the present study in both transplanted and chemically-induced brain tumors, might be due to the blockage of autocrine inhibitory factors dependent on the cyclooxygenase pathway or by increased vascular permeability and blood supply to the tumor due to inhibition of platelet aggregation. In contrast, the inhibition of tumor growth obtained with low ASA doses in transplanted glioma might be due to different mechanisms such as the induction of apoptosis.

Quinacrine enhances carmustine therapy of experimental rat glioma

OBJECTIVE

The high rate of mutagenesis in malignant cells has been considered to be a primary factor in the appearance of chemotherapy-resistant cell clones in glioblastomas. Quinacrine binds strongly to deoxyribonucleic acid, preventing mutagenesis. We investigated whether quinacrine could improve carmustine therapy in C6 cell cultures and in C6 malignant gliomas implanted subcutaneously into Wistar rats.

METHODS

A potential chemopreventive effect of quinacrine on acquired resistance to carmustine therapy was studied in vitro and in vivo. Deoxyribonucleic acid damage was measured in cultured C6 cells by using the micronucleus test. Wistar rats with subcutaneously implanted C6 gliomas were treated with carmustine, quinacrine, or carmustine plus quinacrine, using pharmacological schemes similar to those used for human patients.

RESULTS

The addition of quinacrine to cultured C6 cells did not modify carmustine-induced cytotoxicity; however, the deoxyribonucleic acid damage in surviving cells was minor, as indicated by the frequency of micronucleated cells. The surviving cells continued to be susceptible to a second exposure to carmustine, in contrast to non-quinacrine-treated control cells, which developed resistance to carmustine in a subsequent exposure (P < 0.05). The rate of tumor remission was higher for glioma-bearing rats treated with quinacrine plus carmustine, compared with rats treated with carmustine alone (P < 0.01).

CONCLUSION

The addition of quinacrine to carmustine therapy increases the antineoplastic effect of the carmustine therapy. Our results suggest that chemical inhibition of mutagenesis in malignant glial cells during chemotherapy prevents the appearance of resistant clones.

Neurocysticercosis: validity of ELISA after storage of whole blood and cerebrospinal fluid on paper

Cysticercosis is an infestation of Cysticercus cellulosae. When it occurs in the brain, chronic neurological complications can ensue, most commonly seizures. Neurocysticercosis is usually diagnosed by neuroimaging, a technique not available in most endemic countries. Hence immunological tests are valuable for diagnosis and epidemiological surveys. We evaluated the suitability of paper for storing blood and cerebrospinal fluid (CSF) until subsequent testing by enzyme-linked immunosorbent assay (ELISA), by testing whole blood samples on filter paper from 305 patients and CSF samples from 117 patients stored on ordinary white typing paper and on filter paper. Optimal preservation of biological samples is achieved when whole blood is stored on filter paper, CSF on white paper, and when samples are frozen within 1 week after collection. Our results could improve diagnostic capabilities and facilitate epidemiological surveys in endemic countries where immunodiagnostic tests cannot be rapidly performed because of inadequate laboratory infrastructure.

Treatment of hydrocephalus in adults by placement of an open ventricular shunt

OBJECT

Ventricular shunt placement is the neurosurgical procedure most frequently associated with complications. Over the years, it has been a growing concern that the performance of most shunting devices does not conform to physiological parameters. An open ventriculoperitoneal (VP) bypass with a peritoneal catheter for which the cross-sectional internal diameter was 0.51 mm as a distinctive element for flow resistance was evaluated for use in the treatment of adult patients with hydrocephalus.

METHODS

During a 2-year period, open shunts were surgically implanted in 54 adults with hydrocephalus; conventional shunts were implanted in 80 matched controls. Periodic evaluations were performed using neuroimaging studies and measures of clinical status. All patients were followed from 12 to 36 months. 18.5 +/- 4 months for patients with the open shunt and 19.1 +/- 8.1 months for controls (mean +/- standard deviation). The device continued to function in 50 patients with the open shunt (93%) and in 49 controls (61%: p < 0.001). The Evans index in patients with the open shunt was 0.33 +/- 0.09 throughout the follow up. No cases of infection, overdrainage, or slit ventricles were observed: the index in controls was 0.28 +/- 0.08; 60% of them developed slit ventricles. During the follow-up period occlusion occurred in four patients with the open shunt (7%) and in 31 controls (39%: p < 0.001).

CONCLUSIONS

The daily cerebrospinal fluid (CSF) drainage through the open VP shunt is close to 500 ml of uninterrupted flow propelled by the hydrokinetic force generated by the combination of ventricular pressure and siphoning effect. It complies with hydrokinetic parameters imposed by a bypass connection between the ventricular and peritoneal cavities as well as with the physiological archetype of continuous flow and drainage according to CSF production. The open shunt is simple, inexpensive, and an effective treatment for hydrocephalus in adults.

Post-Panning Computer-Aided Analysis of Phagotope Collections Selected with Neurocysticercosis Patient Polyclonal Antibodies Separation of Disease-Relevant and Irrelevant Peptide Sequences

The homology of peptide sequences selected from a 7mer phage display library with antibodies elicited by the multicelled parasite Taenia solium in cerebrospinal fluid and serum of neurocysticercosis (NCC) patients and by antibodies of uninfected control patients with similar neurological complications of other ethiology (non-NCC) were analyzed using a PILEUP-Tudos sequence alignments program. The analysis generated dendrograms bearing two types of sequence clusters, those containing (1) only NCC patients-derived peptides and (2) both NCC- and control non-CC -- patient derivatives. By using ELISA, peptides that were selected by the antibodies were identified predominantly in the NCC-derived clusters. In repeated analysis in which sequences were added or removed, the first type of clusters maintained their structure, while the second type of clusters were split into many separate homology units dispersed throughout the guide tree. These results are interpreted as the ability of the analysis to segregate NCC-specific peptide sequences from other sequences. Altogether, this study demonstrates the high potential of the PILEUP-Tudos computer program to analyze phagotope collections recovered through biopanning with polyclonal antibodies elicited in patients by complex and as yet unknown multiple pathogenic antigens and to separate all phagotopes that are disease-relevant on the basis of the sequence homology.

Taenia solium disease in humans and pigs: an ancient parasitosis disease rooted in developing countries and emerging as a major health problem of global dimensions

This article reviews current knowledge on human and porcine cysticercosis caused by Taenia solium. It highlights the conditions favorable for its prevalence and transmission, as well as current trends in research on its natural history, epidemiology, immunopathology, diagnosis, treatment and prevention. Our opinions on the most urgent needs for further research are also presented.

Bioavailability of praziquantel increases with concomitant administration of food

In the present study we found that after a single oral dose of 1,800 mg of praziquantel, following a high-lipid diet and a high-carbohydrate diet, the maximum levels in plasma increased 243 and 515% and the area under the plasma concentration curve from 0 to 8 h increased 180 and 271%, respectively.

Interstitial quinacrine for elimination of abnormal tissue; therapy of experimental glioma

BACKGROUND

When quinacrine is injected interstitially, an intense migration of leukocytes and accumulation of various lymphokines is obtained locally, and the reaction is followed by cicatricial fibrosis. This property has been used in humans to induce tubal fibrosis in women and pleurodesis in patients with pleural effusion.

METHODS

In a controlled study, a single dose of 150 mg of quinacrine was injected interstitially into a C6 glioma implanted in the subcutaneous tissue of Wistar rats. Changes in size, histologic variations, and microscopic characteristics of leukocyte subpopulations infiltrating the tumor were studied by immunohistochemistry. Tumor necrosis factor and interleukin-1 beta were measured at different times in tumor homogenates.

RESULTS

The day after the injection of quinacrine, infiltration of leukocytes and macrophages was observed, accompanied by an accumulation of proinflammatory endogenous cytokines. Tumoral necrosis soon ensued; complete tumor disappearance was obtained in 72% of the animals. Cicatrization proceeded without injury of perilesional structures. In all controls injected with the vehicle, a large tumor developed (P <.0001).

CONCLUSIONS

Quinacrine, when administered interstitially in a single dose, elicits an intense local recruitment and proliferation of activated immune cells that, at the dose used in this study, induces tissue necrosis within a radius of 1 cm around the site of quinacrine injection, leaving the surrounding tissue unharmed.

[Chemotherapy of cysticercosis. Review about its pharmacokinetics and toxicology]

Neurocysticercosis (NCC) is the most common parasitic infection of the central nervous system. Praziquantel and albendazole are the two cestocide drugs currently used for the treatment of NCC. The present article reviews the studies on the pharmacokinetics of these compounds, both in animals and humans, that have led to more accurate, precise and short treatment schedules for NCC. Toxicological data indicate that both praziquantel and albendazole do not have severe secondary effects in the short term, however, there is still not sufficient information about their long term effects on human health, mainly with respect to albendazole, for which few studies on its effects on human cells are available. These two drugs constitute an effective treatment not only for NCC but also for several helminthiosis. To keep this advantageuos situation, health care professionals should be aware of the necessity of a more rational use of both anthelminthics, since the potentially adverse long term effects could be related to time and dose of exposure as well as to individual susceptibility. In addition, there is always the possibility that the misuse of these compounds could give rise to resistant species, that may represent a significant problem for public health in countries where parasitic diseases are endemic.

Brain tumors in Mexico: characteristics and prognosis of glioblastoma

BACKGROUND

Frequency and clinical characteristics of brain tumors have been studied in several populations from different genetic backgrounds; their peculiarities in the Mexican mestizo population shed light on the descriptive and comparative epidemiologic analysis of the genetic participation in brain tumors.

METHODS

To analyze the frequency of intracranial neoplasms at the National Institute of Neurology and Neurosurgery of Mexico between 1987 and 1994, demographic, clinical, surgical, and neuropathological records were reviewed and compared with other reports. Glioblastoma cases were followed to investigate survival and prognostic factors.

RESULTS

In a seven-year period 1,776 patients with brain tumors were treated; 419 (24%) had pituitary adenoma; 586 (33%) had glioma. Of the latter, 165 had glioblastoma multiforme, representing 28% of all gliomas and 9% of all neoplasms. Mean survival for glioblastoma was 16 months and the longest mean survival was obtained in patients with radical neurosurgical resection plus radiotherapy and chemotherapy. Cumulative analysis showed that 41% of patients survived less than one year, 39% from 1 to 2 years, 12% from 2 to 3 years and 8% more than three years. Factors that showed prognostic significance were age, therapeutic approach, tumor size, and pre- and postoperative clinical status (p < 0.05).

CONCLUSIONS

This study comprises the largest series on the frequency of brain tumors in a Latin American population. When compared with other studies, the proportion of glioma and glioblastoma among brain neoplasms was low whereas pituitary adenoma was high. Mean survival for glioblastoma was similar to other reports; in these patients, the overall therapeutic response is still far from satisfactory.

Cysticercosis: towards the design of a diagnostic kit based on synthetic peptides

Cysticercosis caused by Taenia solium is a very common disease in developing countries that seriously affects human health. Diagnosis can only be confirmed with the aid of computerized tomography or nuclear magnetic resonance (NMR) creating obvious difficulties for epidemiological studies. Reliable immunoassays employing cerebrospinal fluid (CSF) have been developed, based on the use of cysticercal antigens. However, the reliance on parasite material is restrictive. Herein, we report the advances in the design of a diagnostic kit based on immunodominant synthetic peptides, targeting four candidate epitopes KETc1, KETc12, 410 and 413 which were identified from three different clones (KETc1, 12 and 4) selected from a cDNA library of Taenia crassiceps. CSF antibodies against T. solium cysticercal antigens (TCA) as well as the four peptides were determined by enzyme-linked immunoabsorbent assays (ELISA) using two panels of CSF from patients with confirmed neurocysticercosis and other neurological diseases. In the first CSF panel which included patients with high level of antibodies against TCA, KETc12 exhibited almost the same sensitivity (87.5%) as TCA (93.7%) and 100% specificity. In the second panel of 110 CSF collected at random, two peptides (KETc1 and KETc12) exhibited sensitivities of 40 and 36% respectively, and were 100% specific.

Possible association between Taenia solium cysticercosis and cancer: increased frequency of DNA damage in peripheral lymphocytes from neurocysticercosis patients

Helminths, particularly some Schistosoma species, have been associated with cancer in humans. Neurocysticercosis, produced by cysticerci of the helminth Taenia solium, has been associated with the emergence of brain tumours and haematological malignancies. Local tumours, such as glioblastoma, could be explained by the induction of DNA damage in cells surrounding the cysticercus and chronically exposed to an inflammatory host response. However, systemic effects such as haematological malignancies are not easy to understand. The present work was conducted in Mexico to find out whether DNA damage arises in peripheral lymphocytes in patients with neurocysticercosis. We utilized a highly sensitive technique to analyse chromosomal aberrations, in-situ hybridization with probes against chromosomes 1, 2 and 4, and in addition the blocked-cytokinesis technique was used to determine the formation of micronuclei, a peculiar form of DNA damage. The study was made in lymphocytes from 8 patients before and after the administration of praziquantel, 1 of the 2 drugs used for neurocysticercosis treatment. The frequencies of chromosome aberrations and micronuclei in peripheral blood lymphocytes were higher in the infected patients as compared to those observed both in healthy donors and in the group of patients after praziquantel therapy. Our results suggest that chromosome aberrations induced in peripheral cells during neurocysticercosis could be associated with the development of haematological neoplasias.

A proposal to declare neurocysticercosis an international reportable disease

Neurocysticercosis is an infection of the nervous system caused by Taenia solium. It is the most important human parasitic neurological disease and a common cause of epilepsy in Africa, Asia, and Latin America, representing enormous costs for anticonvulsants, medical resources and lost production. Neurocysticercosis is a human-to-human infection, acquired by the faecal-enteric route from carriers of intestinal T. solium, most often in areas with deficient sanitation. Intestinal tapeworms cause few symptoms, but adult taeniae carried by humans release large numbers of infective eggs and are extremely contagious. Ingestion of poorly cooked pig meat infested with T. solium larvae results in intestinal taeniosis but not neurocysticercosis. With a view to hastening the control of taeniosis and neurocysticercosis we propose that neurocysticercosis be declared an international reportable disease. New cases of neurocysticercosis should be reported by physicians or hospital administrators to their health ministries. An epidemiological intervention could then be launched to interrupt the chain of transmission by: (1) searching for, treating and reporting the sources of contagion, i.e. human carriers of tapeworms; (2) identifying and treating other exposed contacts; (3) providing health education on parasite transmission and improvement of hygiene and sanitary conditions; and (4) enforcing meat inspection policies and limiting the animal reservoir by treatment of pigs. We believe that the first step required to solve the problem of neurocysticercosis is to implement appropriate surveillance mechanisms under the responsibility of ministries of health. Compulsory notification also has the major advantage of providing accurate quantification of the incidence and prevalence of neurocysticercosis at regional level, thus permitting the rational use of resources in eradication campaigns.

[A short praziquantel regimen for the treatment of parenchymatous neurocysticercosis]

OBJECTIVE

Fifteen-day praziquantel therapy for parenchymal neurocysticercosis has been shown to be effective. Plasma and cerebrospinal fluid concentrations of praziquantel peak two hours after administration. Maintenance of high concentrations of the drug for six hours may be an adequate therapy for the disease.

METHODS

Thirty patients with parenchymal neurocysticercosis were treated with three oral doses of praziquantel(25 mg/kg) at two-hour intervals. Intramuscular dexamethasone (10 mg/day) was administered for three days after the praziquantel treatment.

RESULTS

Cysts disappeared in 21 patients and showed a decrease in number of 30 to 60% in seven patients. Two patients remained without change. Considering the total number of cysts, this therapy showed a 70.7% eradication rate. Two patients had seizures, six reported headache, and nausea was frequently reported. Patients under antiepileptic treatment did not have seizures.

CONCLUSION

The cost and duration of treatment with praziquantel were significantly reduced and the inflammation that follow the destruction of the parasite was treated sequentially.

Beta-adrenergic receptor blockade as a therapeutic approach for suppressing the renin-angiotensin-aldosterone system in normotensive and hypertensive subjects

Although beta-adrenergic-blocking drugs suppress the renin system (RAAS), plasma angiotensin II (Ang II) responses during beta-blockade have not been defined. This study quantifies the effects of beta-blockade on the RAAS and examines its impact on prorenin processing by measuring changes in the ratio of plasma renin activity (PRA) to total renin. In normotensive (N = 14) and hypertensive (N = 16) subjects, blood pressure (BP), heart rate, PRA, plasma prorenin, plasma total renin (prorenin + PRA), ratio of PRA to total renin (%PRA), plasma Ang II, and urinary aldosterone were measured before and after 1 week of beta-blockade. Plasma renin activity, Ang II, and urinary aldosterone levels were similar for normotensive and hypertensive subjects. Plasma renin activity correlated with Ang II. Total renin, which is proportional to (pro)renin gene expression, was lower in hypertensive subjects and was inversely related to BP. Beta-blockade decreased BP and heart rate in both groups, with medium- and high-renin hypertensive subjects responding more frequently than those with low renin. Beta-blockade consistently suppressed PRA, Ang II, and aldosterone. Total renin was unchanged, thus, %PRA fell. These results indicate that beta-blockers suppress plasma angiotensin II levels, in parallel with the marked reductions in PRA and urinary aldosterone levels in normotensive and hypertensive subjects. The suppression of Ang II levels was comparable to that produced during angiotensin converting enzyme (ACE) inhibition. However, by reducing prorenin processing to renin, beta-blockers do not stimulate renin secretion, unlike ACE inhibitors and Ang II receptor antagonists. This unique action of beta-blockers has important implications for the treatment of cardiovascular disease.