Development of a non-titration potentiometric method for the determination of acidity in vinegar

The acidity of a solution is associated with the concentration of Brønsted acids. This work proposes a new non-titrimetric potentiometric method using citrate buffer for the determination of vinegar acidity. The difference between the pH values before and after the addition of a diluted vinegar sample to 10 mmol L^-1 citrate buffer (pH 5.5) was related to the acetic acid concentration. The dynamic range of the quadratic analytical curve was from 3.5 to 20 mmol L^-1 (R² = 0.998). The repeatability was 0.8% for acetic acid at 0.01 mol L^-1. Comparison with the conventional titration method showed an error between 0.7% and 4.64% (n = 9) for analysis of commercial vinegar samples The behaviour of the system could be explained using the buffering function.

Global Forum of Cancer Surgeons: Cancer Surgery During the COVID-19 Pandemic: Impact and Lessons Learned

Background

The purpose of this article is to summarize the opinions of the surgical oncology leaders from the Global Forum of Cancer Surgeons (GFCS) about the global impact of COVID-19 pandemic on cancer surgery.

Methods

A panel session (virtual) was held at the annual Society of Surgical Oncology 2021 International Conference on Surgical Cancer Care to address the impact of COVID-19 on cancer surgery globally. Following the virtual meeting, a questionnaire was sent to all the leaders to gather additional opinions. The input obtained from all the leaders was collated and analyzed to understand how cancer surgeons from across the world adapted in real-time to the impact of COVID-19 pandemic.

Results

The surgical oncology leaders noted that the COVID-19 pandemic led to severe disruptions in surgical cancer care across all domains of clinical care, education, and research. Several new changes/protocols associated with increased costs were implemented to deliver safe care. Leaders also noted that preexisting disparities in care were exacerbated, and the pandemic had a detrimental effect on well-being and financial status.

Conclusions

The COVID-19 pandemic has led to severe disruptions in surgical cancer care globally. Leaders of the GFCS opined that new strategies need to be implemented to prepare for any future catastrophic events based on the lessons learned from the current events. The GFCS will embark on developing such a roadmap to ensure that surgical cancer care is preserved in the future regardless of any catastrophic global events.

Isolation and characterization of hydrocarbon-degrading bacteria from gas station leaking-contaminated groundwater in the Southern Amazon, Brazil

Abstract Twenty-three hydrocarbon-degrading bacteria strains were isolated from gas station leaking-contaminated groundwater located in the Southern Amazon, Brazil. Based on hydrocarbon (diesel, hexadecane, benzene, toluene and xylene) degradation ability, two strains were selected for further study. The amplification and sequencing of the 16S rRNA gene showed that these two strains belonged to the genus Bacillus (Bacillus sp. L26 and Bacillus sp. L30). GC-MS analysis showed that strain L30 was the most effective in degrading n-alkane (C10-C27) from diesel after 7 days of cultivation in mineral medium. Both strains produced biosurfactants and showed emulsification activity, specially the strain L30. Alkane hydroxylase gene (group III), which is important for alkane biodegradation, was present in strains. As a result, this study indicated that these bacteria could have promising applications in hydrocarbon bioremediation.

Application of an enhanced homogenization technique to the structural multiscale analysis of a femur bone

Bone is a complex hierarchical material that can be characterized from the microscale to macroscale. This work demonstrates the application of an enhanced homogenization methodology to the multiscale structural analysis of a femoral bone. The use of this homogenization technique allows to remove subjectivity and reduce the computational cost associated with the iterative process of creating a heterogeneous mesh. Thus, it allows to create simpler homogenized meshes with its mechanical properties defined using information directly from the mesh source: the medical images. Therefore, this methodology is capable to accurately predict bone mechanical behavior in a fraction of the time required by classical approaches. The results show that using the homogenization technique, despite the differences between the used homogeneous and heterogeneous meshes, its mechanical behavior is similar. The proposed homogenization technique is useful for a multiscale modelling and it is computationally efficient.

P1795Impact of severe aortic stenosis treatment strategy in low-risk patients: a propensity matched analysis of surgical aortic valve replacement versus transcatheter aortic valve implantation

Introduction

Recent studies suggest that transcatheter aortic valve implantation (TAVI) benefits might extend to lower risk patients. Our goal was to compare the impact of treatment strategy in mortality and peri-procedural complications in a low-risk severe aortic stenosis population.

Methods

Single-center retrospective study which screened patients undergoing intervention from June/2009 to July/2016 (682 isolated aortic valve replacement patients) and from June/2009 to July/2017 (400 TAVI patients). Low-risk was defined as EuroScore II <4% for single non-CABG procedure. After excluding patients with EuroScore II ≥4%, previous cardiac surgery and/or undergoing pre-treatment PCI, 544 AVR and 119 TAVI patients were included.

TAVI patients were propensity score paired in a 1:1 ratio with a group of AVR patients, matched by age, NYHA class, diabetes mellitus, COPD, atrial fibrillation, creatinine clearance and LVEF <50% (mean standardized difference <10% for matching variables). All patients completed at least 1 year of follow-up. Outcomes were adjudicated according to VARC2 criteria.

Results

A total of 158 patients (79 AVR and 79 TAVI) were matched (mean age 79±6 years, 79 men). Median EuroScore II was 2.3% (IQR 1.6–3.0%), 46% were in NYHA class ≥3 and 91% had preserved ejection fraction. Main comorbidities were hypertension (n=105, 67%), diabetes mellitus (n=48, 30%), COPD (n=35, 22%) and coronary artery disease (n=30, 19%). Most patients had at least mild renal function impairment and median creatinine clearance was 58 ml/min (IQR 43–62 ml/min).

The 30-day mortality was 2.5% (n=2 in each group) and there were no differences in in-hospital complications. During a median follow-up of 3.8 years (IQR 2.1–6.1), 67 deaths occurred (39 on the AVR group and 28 on the TAVI group), and treatment strategy did not influence all-cause mortality (HR 0.97, 95% CI 0.60–1.60, log rank p=0.92) - figure 1. By multivariate analysis, need for dialysis during hospitalization remained the only independent predictor of all-cause mortality (adjusted HR 6.40, 95% CI 1.57–28.14, p=0.01).

Figure 1

Conclusion

In this low-risk matched population, treatment strategy did not influence mortality neither complications. Older age, higher NYHA class and renal impairment were the main contributors to the predicted surgical risk. These results suggest that both options are safe for low-risk patients, even though Heart Team remains essential to contemplate other variables that might alter patient management.

P5693Critical sites for scar-related ventricular tachycardias treatment: an approach based on sinus rhythm late activation zones

Introduction

Despite advances in antiarrhythmic and device therapy, ventricular tachycardia (VT) is a major cause of increased morbidity and mortality. During scar-mediated monomorphic VT ablation, the search for critical isthmus sites continues to be the primary goal during successful ablative procedures. However, catheter ablation based on conventional mapping techniques is associated with low success rates and is limited to patients with stable VT.

Objective

The aim of the study was to evaluate, in patients with history of VT, the success of a strategy based on substrate mapping and ablation during sinus rhythm.

Methods

Retrospective single center analysis of patients undergoing VT ablation from November 2015 to November 2017. Clinical profiles and procedural details were determined. We used high-density structural map to identify voltage abnormalities as well a functional map of sinus rhythm activation to identify the regions of late potentials. Radiofrequency applications were performed in the areas with the latest activation. Recurrence of VT was considered the end-points of the follow-up.

Results

A total of 22 patients were included in the analysis, 95% male, with an median age of 65,5 (57–71) years old. The majority of the patients (18) with ischemic cardiomyopathy, 3 with nonischemic cardiomyopathy, and 1 with arrhythmogenic right ventricular cardiomyopathy were included. Epicardial mapping was performed in 27% of the cases. CARTO mapping system was used in 10 patients and Rhythmia in the remaining cases. Areas with the latest activation corresponded to regions of abnormal voltage in 21 patients. During a 26,5 (21,5–29,3) months of follow-up, the observed VT recurrence rate was 35%. 25% of the patients needed hospital admission due to arrhythmias and one patient died due to an arrhythmic cause. Treatment success was higher in epicardial approach (100% VS 50%, p=0,03). The location of the scar in the left ventricle was not a determinant of success (anterior-66,7% VS lateral/inferior-61,5%, p=0,806).

Conclusion

A substrate-based approach that targets regions of late activation within the scar seems attractive and may be a simple way to perform VT ablation with success. In our population, this strategy seams successful, especially in epicardial approach. Substrate modification strategies aiming to eradicate all potential reentrant circuits may be the most successful way to treat VT and avoid recurrences.

Ecotoxicological risks of calcium nitrate exposure to freshwater tropical organisms: Laboratory and field experiments

This study aimed to analyze laboratory and field data to assess the ecotoxicological risks of calcium nitrate exposure to freshwater tropical biota. Short-term laboratorial tests resulted in estimated EC₅₀ values of 76.72 (67.32-86.12)mg N-NO₃₋ L(-1) for C. silvestrii and 296.46 (277.16-315.76) mg N-NO₃₋ L(-1) for C. xanthus. Long-term laboratorial tests generated IC₂₅ values of 5.05 (4.35-5.75) and 28.73 (26.30-31.15) mg N-NO₃₋ L(-1) for C. silvestrii and C. xanthus, respectively. The results from in situ mesocosm experiments performed in the Ibirité reservoir (a tropical eutrophic urban water body located in SE Brazil) indicated that C. silvestrii and C. xanthus were not under severe deleterious acute impact due to the treatment because the higher nitrate concentrations determined were 5.2 mg N-NO₃₋ L(-1) (t=24 h; sediment-water interface) and 17.5 mg N-NO₃₋ L(-1) (t=600 h; interstitial water). However, an abrupt decrease in the densities of Cyanophyceae members and other benthic taxa was observed. In summary, the present work contributes greatly to the toxicity data linked to two taxonomically distinct organisms that have never been screened for calcium nitrate sensitivity. Furthermore, considering the problem of the management and restoration of eutrophic environments, our study reports a comprehensive field assessment that allows the elucidation of the possible toxic impacts caused by the addition of calcium nitrate (a remediation technique) on aquatic and benthic organisms as well as the implications on the aquatic ecosystem as a whole, which may greatly allow expanding the current knowledgebase on the topic.

Validation and evaluation of VapA-specific IgG and IgG subclass enzyme-linked immunosorbent assays (ELISAs) to identify foals with Rhodococcus equi pneumonia

REASONS FOR PERFORMING STUDY

Rhodococcus equi (Rhodococcus hoagii/Prescottella equi) is a common cause of foal pneumonia, but its diagnosis remains a challenge for equine veterinarians. While the VapA-specific (virulence-associated protein A) immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) has low sensitivity and specificity for detecting pneumonic foals, little is known about VapA-specific IgG subclasses.

OBJECTIVES

To evaluate the performance of VapA-specific ELISA for IgG and its subclasses IgGa, IgGb and IgG(T) in the early diagnosis of pneumonia caused by R. equi.

STUDY DESIGN

Assay validation followed by assessment of diagnostic performance using archived samples from animals of known status.

METHODS

Serum samples from exposed (n = 125) and nonexposed adult horses (n = 10) and from experimentally challenged and naturally infected foals were used for ELISA validation. Post mortem and tissue culture records of the last 24 years from the Institute for Experimental Pathology at the University of Iceland in Keldur, Iceland laboratory were evaluated to confirm the absence of R. equi cases in Iceland. The diagnostic performance of VapA-specific IgG and its subclasses was evaluated using banked serum samples from pneumonic (n = 21) and healthy foals (n = 80). To evaluate each IgG assay, a cut-off value was selected based on receiver operating characteristic curve analysis and used to calculate sensitivity and specificity. The intra- and interassay coefficients of variation were calculated for each ELISA.

RESULTS

Using sera from Iceland, where R. equi infection has not been reported, the VapA-specific IgG ELISA differentiated exposed from nonexposed horses. When used to identify infected foals, VapA-specific IgG, IgGa and IgGb had no diagnostic value. In contrast, IgG(T) had high sensitivity and specificity.

CONCLUSIONS

Horses from Iceland are not exposed to VapA(+) R. equi and can serve as negative controls. VapA-specific IgG subclasses, with the exception of IgG(T), are poor predictors of disease. Further investigation on the use of IgG(T) as a diagnostic tool in field conditions is needed.

Administration of commercial Rhodococcus equi specific hyperimmune plasma results in variable amounts of IgG against pathogenic bacteria in foals

Rhodococcus equi is the most common cause of pneumonia in young foals. A vaccine is not available and the use of R equi-specific hyperimmune plasma (HIP) is common. Despite its widespread use, the efficacy of HIP in preventing disease remains controversial. The objectives of this study were (1) to evaluate the virulence associate protein A (VapA)-specific IgG and IgG subclasses in commercially available R equi HIP and (2) to evaluate serum VapA-specific IgG and IgG subclasses in foals following administration of commercial R equi HIP. Three different lots from four commercial R equi HIP were sampled. VapA-specific IgG and IgG subclasses were evaluated in all samples using an ELISA. Serum was collected from newborn foals either after commercial R equi HIP was administered (n=97) or not (n=70). Serum was also collected from each mare. Administration of HIP significantly (P<0.001) increased VapA-specific IgGs in recipient foals, however, there was a marked variation in VapA-specific IgGs in foals receiving the same product. VapA-specific IgGs were significantly different (P<0.001) between products and varied between lots, with coefficients of variation ranging from 17 to 123 per cent. These results may explain previously reported disparities in HIP efficacy.

Astrocyte pathology in the prefrontal cortex impairs the cognitive function of rats

Interest in astroglial cells is rising due to recent findings supporting dynamic neuron-astrocyte interactions. There is increasing evidence of astrocytic dysfunction in several brain disorders such as depression, schizophrenia or bipolar disorder; importantly these pathologies are characterized by the involvement of the prefrontal cortex and by significant cognitive impairments. Here, to model astrocyte pathology, we injected animals with the astrocyte specific toxin L-α-aminoadipate (L-AA) in the medial prefrontal cortex (mPFC); a behavioral and structural characterization two and six days after the injection was performed. Behavioral data shows that the astrocyte pathology in the mPFC affects the attentional set-shifting, the working memory and the reversal learning functions. Histological analysis of brain sections of the L-AA-injected animals revealed a pronounced loss of astrocytes in the targeted region. Interestingly, analysis of neurons in the lesion sites showed a progressive neuronal loss that was accompanied with dendritic atrophy in the surviving neurons. These results suggest that the L-AA-induced astrocytic loss in the mPFC triggers subsequent neuronal damage leading to cognitive impairment in tasks depending on the integrity of this brain region. These findings are of relevance to better understand the pathophysiological mechanisms underlying disorders that involve astrocytic loss/dysfunction in the PFC.

Prevalence of enamel defects related to pre-, peri- and postnatal factors in a Brazilian population

OBJECTIVES

The aim of this paper is to evaluate the prevalence of enamel defects in infants from a socially and economically poor population and the possible association of these defects with disturbances occurring in the pre-, peri- and postnatal periods of human development.

PARTICIPANTS

117 infants aged between 16 and 18 months old were included in four groups based on gestational age and whether part or full term pregnancy.

METHOD

The data were collected in two stages: hospital-based, where gestational and birth records were examined, and home-based, where dental examinations and nutrition were evaluated. The teeth were cleaned and dried with gauze and examined in the open air, avoding direct sunlight in the knee-to-knee position. The enamel defects were coded according to the modified Developmental Defects of Enamel Index. Besides this, body weight and height were considered as anthropometric measures for the evaluation of nutritional status by the National Center for Health Statistics standards.

MAIN OUTCOME MEASURES

The data were analyzed using the chi-square and Fisher Exact tests. Besides these tests, logistic regression models were used.

RESULTS

The prevalence of enamel defects was 49.6%, higher in the group of male infants (p<0.001). The most frequent type of defect and the most affected surface were, respectively, diffuse opacity (9.5%) and the buccal surface (83.3%), located in the gingival half (6.7%). The logistic regression model showed that educational level, gestational age and intrauterine growth retardation (IUGR), besides a lack of breastfeeding, increased the probability of enamel defects up to level of 5%.

CONCLUSIONS

The association between enamel defects and the etiologic factors shown in this study suggest the existence of social influences regarding oral health and teeth development.

Infection by Trypanosoma vivax in goats and sheep in the Brazilian semiarid region: from acute disease outbreak to chronic cryptic infection

A study was undertaken to investigate the role of Trypanosoma vivax in sheep and goat mortality and abortions in the Brazilian semiarid region, where outbreaks had been previously reported in bovines. For this purpose, 177 goats and 248 sheep (20% of herds) were randomly sampled on four farms in the State of Paraiba in May and October 2008. The animals were screened for trypanosomes by the buffy coat technique (BCT) and PCR. Infected animals, approximately 25% in both surveys, manifested apathy, pale mucous membranes, enlarged lymph nodes, weakness, weight loss, opacity of the cornea, blindness and abortion. However, the animals with acute and severe disease showing the highest levels of parasitemia and fever, which many times resulted in death, were only detected in the first survey. These severely diseased animals exhibited progressive weight loss and had the smallest packed cell volume (PCV) values. During survey 2, done in October 2008 on the same farms, only animals with low parasitemia and normal temperatures, PCV values and body weights were detected. Therefore, animals that spontaneously recovered from acute infection developed chronic and asymptomatic disease. This finding demonstrated for the first time that sheep and goats, which are the most important livestock in the semiarid region of Brazil, may be severely injured by T. vivax infection and also play a role as asymptomatic carriers and important sources of T. vivax to ruminants in general.

[Aspects of tobacco attributable mortality: systematic review]

The objective of the article was to assess methodologies published and applied in calculating mortality attributable to smoking. A review of the literature was made for the period 1990 to 2006, in the electronic databases MEDLINE and LILACS. A total of 186 studies were found, which measured mortality based on calculating the smoking-attributable risk. Of these, a total of 41 were selected. The studies that were carried out in the United States and Canada presented a more standard methodology and reported smoking attributable mortality to be 18%-23%, with male mortality being 25%-29% and female mortality 14%-17%. The variations can be attributed to methodological differences and to different estimates of the main tobacco-related illnesses.

Aspectos da mortalidade atribuível ao tabaco: revisão sistemática

O artigo teve por objetivo analisar as metodologias publicadas e empregadas no cálculo da mortalidade atribuível ao fumo. Foram pesquisadas as bases de dados eletrônicas MEDLINE, LILACS entre 1990 e 2006. Foram encontrados 186 estudos que apresentaram a mensuração de mortalidade a partir do cálculo da fração atribuível ao fumo. Desses, foram selecionados 41 artigos. Os estudos realizados nos Estados Unidos e Canadá apresentaram metodologia uniformizada e taxas de mortalidade entre 18%-23%; 25%-29% no sexo masculino e 14%-17% no feminino. As variações metodológicas podem justificar as diferenças da mortalidade entre os estudos e nas estimativas para as principais doenças tabaco-relacionadas.

Occurence of larval Culicidae (Diptera) in water retained in Aquascypha hydrophora (Fungus: Stereaceae) in Central Amazônia, Brazil

The community structure of insects, especially mosquito larvae, in water held in the fungus Aquascypha hydrophora (Berk.) Reid (Stereaceae) is reported. The study was done in the Adolpho Ducke Forest Reserve, 26 km east of Manaus, AM, Brazil, from September 1998 through November 1999. The most abundant entomofauna were immature Culicidae (n = 121) 91.7%, followed by adult Dytiscidae (n = 3) 2.3%, immature Chironomidae (n = 5) 3.8% and immature Tipulidae (n = 3) 2.3%. Culicidae associated with A. hydrophora comprised species of the subfamilies Anophelinae and Culicinae.

Major constituents of the foliar epicuticular waxes of species from the Caatinga and Cerrado

The epicuticular waxes of leaves of four species (Aspidosperma pyrifolium, Capparis yco, Maytenus rigida and Ziziphus joazeiro) from the Caatinga, (a semi-arid ecosystem of Northeast Brazil) and four species (Aristolochia esperanzae, Didymopanax vinosum, Strychnos pseudoquina and Tocoyena formosa) from the Cerrado, (a savanna ecosystem covering one third of the Brazilian territory), were analyzed. Six species contained a high content (above 60 microg x cm(-2)) of wax, four of them from the Caatinga. Triterpenoids and n-alkanes were the most frequent and abundant constituents found in the species from both habitats. The distribution of n-alkanes predominated by homologues with 27, 29, 31 and 33 carbon atoms, displayed no consistent differences between species from the two habitats. Lupeol, beta-amyrin, epifriedelinol and ursolic acid were the triterpenoids found. Triterpenoids clearly predominate over alkanes in the waxes from the Cerrado species. The waxes of two evergreen species from the Caatinga yielded n-alkanes as predominant constituents. A comparison of foliar epicuticular waxes of native plants from ecosystems with different hydric constraints is discussed.

[Deflazacort and colonic anastomotic healing. An experimental study in rats]

BACKGROUND

Deflazacort, a new corticosteroid is claimed to induce less collateral effects than other corticoids. The aim of this study was to investigate the effect of this drug on the healing of colonic anastomosis.

MATERIAL AND METHOD

75 Wistar rats were randomized to receive daily by gavage, one of the following treatments: control group (N=24) - 1 ml of saline; deflazacort (N=25) - 1 ml of this drug containing 0.15mg/ml (0,1 mg/kg/day), and dexamethasone (N=26) - 1 ml containing 0.03 mg/ml of this drug (0.5 mg/kg/day). After 6 days of treatment, the animals underwent laparotomy followed by section and immediate colonic anastomoses in a point 2 cm above peritoneal reflexion. Treatment in each group was carried out until the animals were killed on the third of a six postoperative day. At necroscopy, signs of peritonitis and anastomotic dehiscence were registered. Anastomotic site was tested for tensile rupture and biopsies containing all layers were sent for hydroxyproline and protein measurements.

RESULTS

There was no difference in the peritonitis and anastomotic dehiscence rates among the groups. Bowel rupture pressure was similar at day 3 but significantly higher in controls (180 [150-230] mmHg) than in deflazacort (150 [120-180] mmHg) and dexamethasone groups (140 [100-180] mmHg) at day 6. No difference occurred in the hydroxyproline concentration. Protein content was higher in dexamethasone group than in controls on the third postoperative day.

CONCLUSIONS

Corticosteroids may impair colonic anastomotic resistance and deflazacort may have similar deleterious effects of dexamethasone in anastomotic healing.

PCR-based diagnosis of a case of herpetic whitlow in an AIDS patient

Herpetic infections are common complications in AIDS patients. The clinical features could be uncommon and antiviral chemotherapy is imperative. A rapid diagnosis could prevent incorrect approaches and treatment. The polymerase chain reaction is a rapid, specific and sensible method for DNA amplification and diagnosis of infectious diseases, especially viral diseases. This approach has some advantages compared with conventional diagnostic procedures. Recently we have reported a new PCR protocol to rapid diagnosis of herpetic infections with suppression of the DNA extraction step. In this paper we present a case of herpetic whitlow with rapid diagnosis by HSV-1 specific polymerase chain reaction using the referred protocol.

Analysis of Usnea fasciata crude extracts with antineoplastic activity

Different fractions, isolated from the lichen Usnea fasciata, were analyzed by PC, TLC, and RP-HPLC. Analysis of the organic phases, mainly containing phenolics, revealed that usnic acid is the main product from secondary metabolites, whereas the polysaccharides isolichenin and raffinose are the most abundant water-soluble carbohydrates. Fractions containing usnic acid, as well as those containing isolichenin, showed moderate activity against sarcoma 180 and Ehrlich tumor cells. High antitumoral activity, near 90% inhibition, was found associated with the fraction containing raffinose.

Parenteral isradipine reduces blood pressure in hypertensive crisis

The efficacy and tolerability of an infusion of isradipine, a calcium antagonist of the dihydropyridine type, were tested in patients in hypertensive crisis. Ten patients with symptomatic and significant elevations in blood pressure were infused for 12 h with isradipine at 1.2, 2.4, 4.8, and 7.2 micrograms/kg/h (3 h of each infusion level). No untoward effects or adverse reactions were noted. No alterations were observed on electrocardiographic tracings, and blood pressure was significantly reduced only at doses of 7.2 micrograms/kg/h. Thus, isradipine as an infusion is useful and safe for hypertensive crisis, starting at a rate of 7.2 micrograms/kg/h. Higher doses may yet prove to be safe, well tolerated, and even more efficacious.

[Schistosoma mansoni: experimental infection in mice through the ear and quantification of the parasitism in the skin]

No presente trabalho, desenvolveu-se método de infecção de camundongos através da orelha e de recuperação de esquistossômulos resultantes dessas infecções. Cerca de 80% das cercarías postas em contacto com orelhas de camundongos penetraram. Destas, 30% foram recuperadas. como vermes adultos, do sistema porta. Da pele (das orelhas) as maiores recuperações de esquistossômulos ocorreram nos dois primeiros dias após a infecção. Os parasitas permaneceram nesse sítio por dois dias. No terceiro dia, os parasitas foram recuperados tanto da pele como dos pulmões. A partir do 4.° dia, foi predominante a recuperação de esquistossômulos ao nível dos pulmões. Do total de parasitas que potencialmente atingiriam o sistema porta, proporção elevada (73-80%) pode ser recuperada da pele, no segundo dia após a infecção, como esquistossômulos. Revelando-se apropriadas ao acesso, à migração no hospedeiro e às técnicas de recuperação de parasitas, sugere-se que orelhas de camundongos podem ser utilizadas como sítio de infecção para estudos que visem a análise parasitológica dos eventos iniciais da infecção em animais normais ou imunes.

Anaphylaxis with Schistosoma mansoni extracts in normal and infected mice

Methods generally utilized for studies on anaphylaxis to protein antigens such as determination of histamine release to the blood, hemoconcentration, histamine release from peritoneal mast cells and passive cutaneous anaphylaxis (PCA) were used to investigate some aspects of the anaphylaxis to parasite antigens in Schistosoma mansoni infected mice. The release of histamine to the blood and significant rates of hemoconcentration were induced by intravenous injection of schistosomula or cercarial extracts into 10-13 weeks infected mice. Cercarial, schistosomula, worm tegument and soluble egg antigens were able to trigger histamine release from peritoneal mast cells from chronically infected mice. In spite of the PCA reaction beeing detected within 2 hours of sensitization (IgG1antibodies) in 6 of 8 tested sera from chronically infected mice, no detectable reactions were obtained after 48 hours sensitization (IgE antibodies). Although IgE was not detected in the circulation, by the PCA technique, the results indicate that the infected mice contained IgE antibodies bound to their mast cells.