Towards the development of an epitope-focused vaccine for SARS-CoV-2

The rapid spread of COVID-19 on all continents and the mortality induced by SARS-CoV-2 virus, the cause of the pandemic coronavirus disease 2019 (COVID-19) has motivated an unprecedented effort for vaccine development. Inactivated viruses as well as vaccines focused on the partial or total sequence of the Spike protein using different novel platforms such us RNA, DNA, proteins, and non-replicating viral vectors have been developed. The high global need for vaccines, now and in the future, and the emergence of new variants of concern still requires development of accessible vaccines that can be adapted according to the most prevalent variants in the respective regions. Here, we describe the immunogenic properties of a group of theoretically predicted RBD peptides to be used as the first step towards the development of an effective, safe and low-cost epitope-focused vaccine. One of the tested peptides named P5, proved to be safe and immunogenic. Subcutaneous administration of the peptide, formulated with alumina, induced high levels of specific IgG antibodies in mice and hamsters, as well as an increase of IFN-γ expression by CD8+ T cells in C57 and BALB/c mice upon in vitro stimulation with P5. Neutralizing titers of anti-P5 antibodies, however, were disappointingly low, a deficiency that we will attempt to resolve by the inclusion of additional immunogenic epitopes to P5. The safety and immunogenicity data reported in this study support the use of this peptide as a starting point for the design of an epitope restricted vaccine.

A unique immune signature of serum cytokine and chemokine dynamics in patients with Zika virus infection from a tropical region in Southern Mexico

OBJECTIVES

To describe the kinetics of circulating cytokines and chemokines in humans with ZIKAV infection.

METHODS

Serum levels of different immune mediators in patients with ZIKAV infection were measured at distinct stages of the disease, as well as in culture supernatants from human monocytes infected with a clinical ZIKAV isolate. We also looked for clinical features associated with specific immune signatures among symptomatic patients.

RESULTS

We evaluated 23 ZIKAV-infected patients. Their mean age was 32 ± 8.3 years and 65% were female. ZIKAV patients showed elevated IL-9, IL-17A, and CXCL10 levels at acute stages of the disease. At day 28, levels of CCL4 and CCL5 were increased, whereas IL-1RA, CXCL8 and CCL2 were decreased. At baseline, IL-7 was increased among patients with headache, whereas CCL2, and CCL3 were decreased in patients with bleeding and rash, respectively. Our clinical ZIKAV isolate induced a broad immune response in monocytes that did not resemble the signature observed in ZIKAV patients.

CONCLUSIONS

We showed a unique immune signature in our cohort of ZIKAV-infected patients. Our study may provide valuable evidence helpful to identify immune correlates of protection against ZIKAV.

Dysregulated expression of hypoxia-inducible factors augments myofibroblasts differentiation in idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is an age-related, progressive and lethal disease, whose pathogenesis is associated with fibroblasts/myofibroblasts foci that produce excessive extracellular matrix accumulation in lung parenchyma. Hypoxia has been described as a determinant factor in its development and progression. However, the role of distinct members of this pathway is not completely described.

METHODS

By western blot, quantitative PCR, Immunohistochemistry and Immunocitochemistry were evaluated, the expression HIF alpha subunit isoforms 1, 2 & 3 as well, as their role in myofibroblast differentiation in lung tissue and fibroblast cell lines derived from IPF patients.

RESULTS

Hypoxia signaling pathway was found very active in lungs and fibroblasts from IPF patients, as demonstrated by the abundance of alpha subunits 1 and 2, which further correlated with the increased expression of myofibroblast marker αSMA. In contrast, HIF-3α showed reduced expression associated with its promoter hypermethylation.

CONCLUSIONS

This study lends further support to the involvement of hypoxia in the pathogenesis of IPF, and poses HIF-3α expression as a potential negative regulator of these phenomena.

Abstract P5-15-04: Oncotype DX cost effectivity to a Brazilian public hospital

Introduction: The Oncotype DX was associated to 14% of adjuvant chemotherapy administration to Hormonal Receptor positive (HR+) and HER2 negative, T1N0 or T2N0 breast cancer patients at Tailor X trial recently published (RS>25)

Objective: To describe the adjuvant chemotherapy administration to a Brazilian public hospital for HR+ HER2 negative, T1N0 or T2N0 breast cancer patients. And the estimate the cost effectivity of Oncotype DX in our low income scenary.

Materials and Methods:This retrospective cross-sectional study was conducted at the Oncology Division of the Women's Hospital - CAISM of the State University of Campinas (UNICAMP), Brazil. All patient data were found from the hospital records from 2007 to 2009. It was included T1N0 and T2N0 HR+/HER2 negative breast cancer patients. Patients submitted to neoadjuvant treatment were excluded.

We calculate the final cost of different types of chemotherapy used and the potential impact to oncotype DX introduction in this scenary.

Results: It was found 109 patients records. 66% (72/109) had received adjuvant chemotherapy. 35% (38/109) had AC (X6), 29% (32/109) had CMF (X6) and 2% (2/109) had AC-T (X4). The total cost for chemotherapy scheme were; AC (X6) US$ 346,9; CMF (X6), US$300,6; ACT (X4), US$395,9. The total cost of chemotherapy was US$ 23.596,83 to 72 patients. If we consider 14% (15/109) of adjuvant chemotherapy associate to a Oncotype DX use (Tailor X RS>25), It would reduce adjuvant chemotherapy administration to 15 patients. The chemotherapy cost would be US$ 4588,27. In our scenary, It could save US$ 19.008,56. Nevertheless, the Oncotype Dx cost to Brasil is US$ 3.200,00 for each test. To 109 patients the total cost would be (109 X US$ 3.200,00) US$ 348.800,00. Therefore, the total cost for Oncotype DX program plus adjuvant chemotherapy for our patients would be US$ 348.800,00 + US$ 4.588,27= US$ 353.388,27. While in the real situation we had spent US$ 23.596,83. The total estimate cost would be 15 times more.

Conclusion: At the moment, because of the assay high cost and the low cost of the adjuvant chemotherapy to HR+, HER2 negative T1N0 and T2N0, It would be difficult to consider Oncotype DX cost-effective to Brazilian public heath system. Even considering many advantages to spare chemotherapy to this population.

Citation Format: Cabello C, de Andrade RN, Cabello TF, Teixeira S, da Costa LS, Ramalho S. Oncotype DX cost effectivity to a Brazilian public hospital [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-15-04.

Abstract P4-02-09: Breast cancer and magnetic resonance imaging (MRI): Background parenchymal enhancement (BPE) predicting response to neoadjuvant chemotherapy (NAC)

Objective: To assess the association of MRI BPE and pathological response in women diagnosed with stage II/III breast cancer submitted to NAC. Methods: This observational and cross-sectional retrospective study was performed in consecutive women who underwent NAC and had MRI exams before and after chemotherapy. The MRI was done before and after 2 weeks of completing NAC. BPE was classified according to ACR-BIRADS 5th edition. The type of BPE before NAC, its changes and the relationship to total pathologic complete response (TpCR) were evaluated. Data were paired with patient age, size on MRI before and after NAC, features of clinical response according to the RECIST criteria, tumor grade and immunohistochemical (IHC) subtypes. MRI assessment included amount of fibroglandular tissue, symmetry of BPE and measurement of tumor at the longest diameter. All images were blinded reviewed by a radiologist. We used for the changes of the BPE the Bowker symmetry test or the McNemar test and to analyze the factors related to the clinical and pathologic responses, logistic regression analysis. The level of significance adopted was 5% (p<0.05). Results: We studied 71 women between 2009 and 2016. The medium age was 37 years old. BPE was symmetrical in 68 women (95.8%). Moderate and marked BPE was present in 28 (39.4%) of the affected breasts and in 25 (34.2%) of the contralateral breasts. After NAC all BPE were symmetrical and just 3% of them were moderate or marked. Regarding the IHC subtype, 40 women (56.3%) were triple negative or HER2 positive, and these women had a higher frequency of TpCR (55% for each, compared to 12.9% in patients with luminal subtypes). We found to be independently associated with pCR: the reduction of BPE (in the affected or contralateral breast) and the molecular subtypes triple negative and HER2 positive

Table 1. Multivariate Analysis related to TpCR (n=71).VariableCategoryP-ValueO.R.*CI 95% O.R.*Tumor Size on MR pre-MAC (cm) 0.1710,8590.691-1.068Luminal subtypeLuminal B (ref.)---1.00--- Luminal A0.3120.450.10-2.11 HER2pos/ Luminal B HER20.0055.781.71-19.58 Triple negative0.0493.271.01-10.64Age (years) 0.3870.9820.942-1.023Nottingham grade1 (ref.)---1.00--- 20.0817.830.78-79.16 30.0967.100.71-71.31BPE pre-NAC (S or A)Asymmetric (ref.)---1.00--- Symmetric0.3273.030.33-27.76BPE pre-NAC affected breastMinimal (ref.)---1.00--- Mild0.8120.860.24-3.09 Moderate0.3711.890.47-7.64 Marked0.5911.570.30-8.17BPE pre-NAC contralateral breastMinimal (ref.)---1.00--- Mild0.7130.790.22-2.81 Moderate0.2502.330.55-9.77 Marked0.4701.880.34-10.43BPE ChangeSame/increased (ref.)---1.00--- Reduction0.0263.011.14-7.96* OR (Odds Ratio) = Risk ratio to pCR; (n=26 pCR, n=7 DpCR, n=31 PR e n=7 ED, where Total pCR is pathological complete response (without invasive and DCIS in the breast and axilla) DpCR is pathological response with just DCIS, PR is partial response and ED is stable disease – we haven't progression disease). CI 95% OR = Confidence interval of 95% to risk ratio. Ref.: reference level. Proportional risk models.

Conclusion: BPE reduction was significantly associated with TpCR. Nevertheless, patterns of BPE pre-NAC have no association with pathological response.

Citation Format: Teixeira SRC, Camargo HSAd, Ramalho S, Natal R, Machado HdC, Camargo MMAd, Azevedo J, Arruda MdS, Negrão EMS, Almeida NR, Teixeira AL, Cabello V, Cabello C. Breast cancer and magnetic resonance imaging (MRI): Background parenchymal enhancement (BPE) predicting response to neoadjuvant chemotherapy (NAC) [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 P4-02-09.

Abstract P4-10-15: Impact of delay in breast cancer diagnosis and treatment according to health insurance status in southwest Brazil and Houston, Texas

Background: Access to medical care vary across the world and is related to different health systems with an impact in recurrence.Objective: To evaluate disparities in breast cancer(BC) diagnosis and treatment between public and private services in southwest Brazil and at two public safety net hospitals in Houston, Texas.Methods: Women diagnosed with BC stages I-III between 2009 to 2011, and treated at the four hospitals in Brazil and two health centers in US were included. All statistical analyses were performed in R studio software, and p<0.05 was considered significant.Results: 1245 women were included: 967 from public health system (PHS) (20.3% from Houston, Texas) and 274 from private system(PS). Recurrence rate was higher in PHS (14.6% vs. 2.6%, p<0.001)

Table 1. Clinical and demographic characteristics of the patientsCharacteristicsPublic (%), n=967Private (%), n=274pDiscovery of BC   By patient530 (54.8)92 (33.5) Routine exam87 (9)109 (39.8) Screening mammography270 (27.9)23 (8.4) Other80 (8.3)50 (18.3)<0.001Initial treatment   Surgery687 (71)241 (88) Neo-adjuvant chemotherapy224 (23.2)27 (9.8) Neo-adjuvant hormone therapy23 (2.3)27 (9.8) Not available33 (3.4)3 (1.1)<0.001Clinical Stage   I293 (30.3)113 (41.2) II342 (35.4)52 (19) III271 (28)15 (5.5) Unknown61 (6.3)94 (34.3)<0.001Subtype   HR+/HER2 -561 (58)192 (70.1) HR-/HER2+108 (11.1)29 (10.6) HR-/HER2+76 (7.9)14 (5.1) Triple negative149 (15.4)28 (10.2) Unknown73 (7.6)11 (4)0.012Symptomatic at Diagnosis   Yes591 (61.1)100 (36.5) No306 (31.6)97 (35.4) Unknown70 (7.2)77 (28.1)<0.001Recurencen=772n=146 No719 (74.4)193 (70.4) Yes142 (14.6)7 (2.6) Unknown106 (11)74 (27)<0.001

. Considering the interval in weeks: symptoms to diagnosis, diagnosis to first treatment (either surgery or neoadjuvant chemotherapy), diagnosis to first systemic treatment, diagnosis to surgical treatment and diagnosis to radiotherapy were longer in public patients (24.1 vs. 8.7; 11.1 vs. 3.5; 18.6 vs. 9.8; 16.9 vs. 5.6; 51.4 vs. 26.1; p<0.001).

Table 2. Delay disparities between public and private health system PublicPrivatepSymptoms to diagnosis   Number of patients575146 Time (weeks)24.1 (0.4-104.9)8.7 (0.0-43.7)<0.001Diagnosis to first treatment   Number of patients663180 Time (weeks)11.1 (2.0-31.5)3.5 (0.0-11.0)<0.001Diagnosis to first systemic treatment   Number of patients526106 Time (weeks)18.6 (2.6-44.7)9.8 (1.9-29.3)<0.001Diagnosis to surgical treatment   Number of patients657178 Time (weeks)16.9 (3.4-45.6)5.6 (0.0-32.9)<0.001Diagnosis to radiotherapy   Number of patients465127 Time (weeks)51.4 (18.7-88.4)26.1 (5.6-66.4)<0.001

In multivariate analysis, PHS (HR 1.72; 95% CI 1.34-1.88; p adj=0.003), presence of symptoms (HR 2.29; 95% CI 1.39-3.78; p adj=0.001), clinical stage III (HR 1.62; 95% CI 1.35-1.93; p adj<0.001), and triple negativity and HER2neu positivity (1.18; 95% CI 1.03-1.35; p adj=0.021) were all associated with a higher recurrence rate.Conclusions: There were significant disparities between PHS and PS. Women in the PHS presented higher rates of recurrence, advanced clinical stages at diagnosis, symptoms and more aggressive subtypes by IHC. additionally, the interval between symptoms to diagnosis and diagnosis to treatments was longer in PHS.

Citation Format: NematiShafaee M, Natal RA, Ramalho S, Dória MT, Conz L, Cabello V, Pavanello M, Mano MS, Linck RDM, Batista LS, Pedro EP, Bines J, de Paula BH, Zucca-Matthes G, Bondy ML, Ellis MJ, Podany E, Debord L, Makawita S, Stewart K, Cabello C. Impact of delay in breast cancer diagnosis and treatment according to health insurance status in southwest Brazil and Houston, Texas [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 P4-10-15.

Circulating levels of miR-150 are associated with poorer outcomes of A/H1N1 infection

BACKGROUND

Overproduction of pro-inflammatory cytokines and chemokines is frequently associated with severe clinical manifestations in patients infected with influenza A/H1N1 virus. Micro-RNAs (miRNAs) are highly conserved small non-coding RNA molecules that post-transcriptionally regulate gene expression and are potential biomarkers and therapeutic targets in different inflammatory conditions.

METHODS

We studied the circulating and miRNA profiles in critically ill A/H1N1 patients, A/H1N1 patients with milder disease, asymptomatic housemates and healthy controls. Cytokine, chemokine and growth factors that were potential targets of differentially expressed miRNAs were assessed. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment and interactome analysis of these miRNAs were also performed.

RESULTS

Critically ill patients exhibited a significant over-expression of circulating miR-150 (p<0.005) when compared to patients with milder disease. miR-29c, miR-145 and miR-22 were differentially expressed in patients with severe A/H1N1 disease whereas miR-210, miR-126 and miR-222 were downregulated in individuals exposed to the A/H1N1 virus. Significant correlations (p<0.05) between circulating levels of miR-150 with IL-1ra, IL-2, IL-6, CXCL8, IFN-γ, CXCL10 and G-CSF were detected, particularly in critically ill patients.

CONCLUSION

The up-regulation of miR-150 is associated with poorer outcomes of A/H1N1 infection. The differential expression of miRNAs related with immune processes in severe A/H1N1 disease supports the potential role of these miRNAs as biomarkers of disease progression.

Borrelia chilensis, a new member of the Borrelia burgdorferi sensu lato complex that extends the range of this genospecies in the Southern Hemisphere

Borrelia burgdorferi sensu lato (s.l.), transmitted by Ixodes spp. ticks, is the causative agent of Lyme disease. Although Ixodes spp. ticks are distributed in both Northern and Southern Hemispheres, evidence for the presence of B. burgdorferi s.l. in South America apart from Uruguay is lacking. We now report the presence of culturable spirochetes with flat-wave morphology and borrelial DNA in endemic Ixodes stilesi ticks collected in Chile from environmental vegetation and long-tailed rice rats (Oligoryzomys longicaudatus). Cultured spirochetes and borrelial DNA in ticks were characterized by multilocus sequence typing and by sequencing five other loci (16S and 23S ribosomal genes, 5S-23S intergenic spacer, flaB, ospC). Phylogenetic analysis placed this spirochete as a new genospecies within the Lyme borreliosis group. Its plasmid profile determined by polymerase chain reaction and pulsed-field gel electrophoresis differed from that of B. burgdorferi B31A3. We propose naming this new South American member of the Lyme borreliosis group B. chilensis VA1 in honor of its country of origin.

Seasonal and pandemic influenza H1N1 viruses induce differential expression of SOCS-1 and RIG-I genes and cytokine/chemokine production in macrophages

BACKGROUND

Infection with pandemic (pdm) A/H1N1 virus induces high levels of pro-inflammatory mediators in blood and lungs of experimental animals and humans.

METHODS

To compare the involvement of seasonal A/PR/8/34 and pdm A/H1N1 virus strains in the regulation of inflammatory responses, we analyzed the changes in the whole-genome expression induced by these strains in macrophages and A549 epithelial cells. We also focused on the functional implications (cytokine production) of the differential induction of suppressors of cytokine signaling (SOCS)-1, SOCS-3, retinoid-inducible gene (RIG)-I and interferon receptor 1 (IFNAR1) genes by these viral strains in early stages of the infection.

RESULTS

We identified 130 genes differentially expressed by pdm A/H1N1 and A/PR/8/34 infections in macrophages. mRNA levels of SOCS-1 and RIG-I were up-regulated in macrophages infected with the A/PR/8/34 but not with pdm A/H1N1 virus. mRNA levels of SOCS-3 and IFNAR1 induced by A/PR/8/34 and pdm A/H1N1 strains in macrophages, as well as in A549 cells were similar. We found higher levels of IL-6, TNF-α, IL-10, CCL3, CCL5, CCL4 and CXCL8 (p < 0.05) in supernatants from cultures of macrophages infected with the pdm A/H1N1 virus compared to those infected with the A/PR/8/34 strain, coincident with the lack of SOCS-1 and RIG-I expression. In contrast, levels of INF-α were higher in cultures of macrophages 48h after infection with the A/PR/8/34 strain than with the pdm A/H1N1 virus.

CONCLUSIONS

These findings suggest that factors inherent to the pdm A/H1N1 viral strain may increase the production of inflammatory mediators by inhibiting SOCS-1 and modifying the expression of antiviral immunity-related genes, including RIG-I, in human macrophages.

In situ molecular identification of the influenza A (H1N1) 2009 Neuraminidase in patients with severe and fatal infections during a pandemic in Mexico City

Background

In April 2009, public health surveillance detected an increased number of influenza-like illnesses in Mexico City’s hospitals. The etiological agent was subsequently determined to be a spread of a worldwide novel influenza A (H1N1) triple reassortant. The purpose of the present study was to demonstrate that molecular detection of pandemic influenza A (H1N1) 2009 strains is possible in archival material such as paraffin-embedded lung samples.

Methods

In order to detect A (H1N1) virus sequences in archived biological samples, eight paraffin-embedded lung samples from patients who died of pneumonia and respiratory failure were tested for influenza A (H1N1) Neuraminidase (NA) RNA using in situ RT-PCR.

Results

We detected NA transcripts in 100% of the previously diagnosed A (H1N1)-positive samples as a cytoplasmic signal. No expression was detected by in situ RT-PCR in two Influenza-like Illness A (H1N1)-negative patients using standard protocols nor in a non-related cervical cell line. In situ relative transcription levels correlated with those obtained when in vitro RT-PCR assays were performed. Partial sequences of the NA gene from A (H1N1)-positive patients were obtained by the in situ RT-PCR-sequencing method. Sequence analysis showed 98% similarity with influenza viruses reported previously in other places.

Conclusions

We have successfully amplified specific influenza A (H1N1) NA sequences using stored clinical material; results suggest that this strategy could be useful when clinical RNA samples are quantity limited, or when poor quality is obtained. Here, we provide a very sensitive method that specifically detects the neuraminidase viral RNA in lung samples from patients who died from pneumonia caused by Influenza A (H1N1) outbreak in Mexico City.

Retrospective serological survey of influenza viruses in backyard pigs from Mexico City

BACKGROUND

In the present study, we analyzed the presence of antibodies to four different influenza viruses (pH1N1, hH1N1, swH1N1, and swH3N2) in the sera of 2094 backyard pigs from Mexico City. The sera were obtained between 2000 and 2009.

OBJECTIVES

The aim of this study was to perform a retrospective analysis of the 2000-2009 period to determine the seroprevalence of antibodies against pH1N1, hH1N1, swH1N1, and swH3N2 viruses in sera obtained from backyard pigs in Mexico City.

METHODS

Antibody detection was conducted with hemagglutination inhibition assay (HI) using four influenza viruses. We used linear regression to analyze the tendency of antibody serum titers throughout the aforementioned span.

RESULTS

We observed that the antibody titers for the pH1N1, swH1N1, and swH3N2 viruses tended to diminish over the study period, whereas the antibodies to hH1N1 remained at low prevalence for the duration of the years analyzed in this study. A non-significant correlation (P > 0.05) between antibody titers for pH1N1 and swH1N1 viruses was observed (0.04). It contrasts with the significance of the correlation (0.43) observed between the swH1N1 and swH3N2 viruses (P < 0.01).

CONCLUSIONS

Our findings showed no cross-antigenicity in the antibody response against the same subtype. Antibodies against pH1N1 virus were observed throughout the 10-year study span, implying that annual strains shared some common features with the pH1N1 virus since 2000, which would then be capable of supporting the ongoing presence of these antibodies.

The impact of lumbar scoliosis on pain, function and health-related quality of life in postmenopausal women

The impact of adult scoliosis on pain, function and health-related quality of life (QOL) has not been clearly defined. A population-based study using widely applied screening tools could better reflect the impact of adult scoliosis. In this study, a visual analog pain scale assessment (VAS) for lumbar and leg pain, an Oswestry disability index (ODI) and a standard version of the Medical Outcome Study Short Form-36 (SF-36) questionnaire were sent by mail to 261 women of age 50 years and older, consecutively evaluated with dual-energy radiograph absorptiometry (DXA) scan images. 138 patients (32 with lumbar curves 10° or bigger) returned the questionnaires. Differences in lumbar VAS, leg VAS, ODI and SF-36 values between groups of patients with curves <10°, 10°-19° and ≥20° were evaluated. Correlation analyses of the Cobb angle, age and body mass index (BMI) with VAS, ODI and SF-36 values, and multivariate regression analysis were performed. Patients with curves <10°, 10°-19° and ≥20° had no significant differences in lumbar or leg VAS, ODI or SF-36 values. ODI values correlated with age and BMI; SF-36 values correlated with BMI only; lumbar and leg VAS values did not correlate with lumbar curvature, age or BMI. Regression disclosed that Cobb angle values did not influence ODI, SF-36 or VAS values. In postmenopausal women with mild and moderate lumbar curves, Cobb angle had no influence on pain, function and QOL; age and BMI had small effect.

Radioguided Intraoperative Margins Evaluation (RIME): Preliminary results of a new technique to aid breast cancer resection

AIMS

Women undergoing breast-conserving surgery for cancer can present residual disease. We have developed a technique called Radioguided Intraoperative Margins Evaluation (RIME) that uses a radiopharmaceutical to distinguish normal and cancer tissues. The aim of this study was to assess whether RIME is a feasible technique, and if it could help in breast cancer resection with free margins, minimizing residual disease.

METHODS

Twenty-three breast cancer patients programmed for mastectomy were selected. Before surgery, the patients were submitted to scintimammography with 99mTc-sestamibi to estimate the optimal time to begin radioguided surgery. Twenty patients were submitted to magnetic resonance imaging (MRI), to evaluate skin, deep fascia and to detect other tumor foci. At the beginning of the surgery, the same dose of 99mTc-sestamibi was intravenously injected into patients. Tumor resection was performed under guidance of a gamma-probe, characterizing the RIME technique. Finally, modified radical mastectomy was performed. Tumor and residual breast were histopathologically examined.

RESULTS

The RIME technique was successfully performed in all patients. The principal tumor was removed by this technique and provided 82.6% of histologically free margins (mean margins, 4.8 mm). Additionally, 47.8% of patients were without residual disease. The mean size of residual carcinoma was 3.67 mm and generally located near the tumor bed (<1.5 cm). There was no significant association between presence of residual disease and tumor size or margin status.

CONCLUSION

RIME is a feasible technique that could help tumor resection with free margins; however, it seems to be limited for small carcinoma foci.

Frequency of viruses associated with acute respiratory infections in children younger than five years of age at a locality of Mexico City

A locality in the district of Tlalpan, Mexico City, was selected in order to identify the viral agents in children younger than 5 years of age with acute respiratory infection (ARI). A total of 300 children were randomly selected and were included in this study for a period of 13 months. During this period nasopharyngeal exudates were collected for the isolation of viral agents. Monoclonal fluorescent antibodies were used for viral identification after cell culture. Viral infection was detected in 65% of the specimens. The respiratory syncytial virus (RSV) was the most common virus agent detected. Children required an average of two consultations during the study period. Two high incidence peaks were observed, one during the summer and the other during winter; the most frequent viruses during these seasons were influenza A and RSV, respectively. The largest number of viruses was isolated in the group of children between 1 and 2 years of age and in the group between 4 and 5 years of age. This study demonstrated the presence of ARI and of different viruses in a period of 13 months, as well as the most frequent viruses in children younger than 5 years of age from a community of Mexico City.