996 resultados para protective group
Resumo:
We describe the use of a murine model to evaluate resistance against subsequent challenge following a primary infection with oncospheres of Echinococcus granulosus. Mice (Kunming strain) were infected with hatched oncospheres of Echinococcus granulosus; 21 days later a second challenge was given by a different route of infection. A primary infection by intraperitoneal (i.p.) injection stimulated 100 and 90.5% protection in terms of reduced cyst numbers against a secondary infection given subcutaneously (s.c.) or intravenously (i.v.) respectively. A primary infection given s.c. followed by i.p. or i.v. challenge resulted in 84.0 and 100% protection, respectively. Intravenous infection followed by i.p. or s.c. challenge resulted in 98.5 and 69.4% protection, respectively. With the i.v. route of infection, almost all resultant cysts were present in the lungs. The data show that a primary infection with oncospheres can induce total or a high degree of protection against a subsequent challenge and confirms that natural (concomitant) immunity can be stimulated in the intermediate host as the result of a primary infection. This may explain the decline in hydatid infection in sheep older than 2 years in hyper-endemic areas such as those found in Xingjiang, China. These older sheep may have been earlier infected and have subsequently self-cured, with the primary infection stimulating an immune response that protects the intermediate host animals from further infection. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.
Resumo:
Purpose: The aims of this randomized controlled trial were to determine whether there were differences in the disease-free survival (DFS) and toxicity between conventional radiotherapy (CRT) and a continuous 3 week accelerated radiotherapy regimen (ART) in stage III and IV squamous cell carcinoma of the oral cavity, oropharynx, larynx and hypopharynx. Patients and methods: Patients from 14 centres throughout Australia and New Zealand were randomly assigned to either CRT, using a single 2 Gy/day to a dose of 70 Gy in 35 fractions in 49 days or to ART, using 1.8 Gy twice a day to a dose of 59.4 Gy in 33 fractions in 24 days. Treatment allocation was stratified for site and stage. The accrual began in 1991 and the trial was closed in 1998 when the target of 350 patients was reached. Results: The median potential follow-up time was 53 months (range, 14-101). The DFS at 5 years was 41% (95% CI, 33-50%) for ART and 35% (95% CI, 27-43%) for CRT (P = 0.323) and the hazard ratio was 0.87 in favour of ART (95% CI, 0.66-1.15). The 5-year disease-specific survival rates were 40% for CRT and 46% for ART (P = 0.398) and the loco-regional control was 47% for CRT vs. 52% for ART (P = 0.300). The respective hazard ratios were 0.88 (95% CI, 0.65-1.2) and 0.85 (0.62-1.16), favouring the accelerated arm. In the ART arm, confluent mucositis was more severe (94 vs. 71%; P < 0.001) and peaked about 3 weeks earlier than in the CRT arm, but healing appeared complete in all cases. There were statistically significant reductions in the probability of grade 2 or greater late soft tissue effects over time in the ART arm (P < 0.05), except for the mucous membrane where late effects were similar in both arms. Conclusions: Differences in DFS, disease-specific survival and loco-regional control have not been demonstrated. ART resulted in more acute mucosal toxicity, but this did not result in greater prolongation of the treatment time compared with the CRT arm. There were less late effects in the ART arm, with the exception of late mucosal effects. This trial has confirmed that tumour cell repopulation occurs during conventionally fractionated radiotherapy for head and neck cancer. However, it has also provided additional evidence that overall improvements in the therapeutic ratio using accelerated fractionation strategies are seriously constrained by the need to limit total doses to levels that do not exceed acute mucosal tolerance. The accelerated schedule tested has been shown in this trial to be an acceptable alternative to conventionally fractionated irradiation to 70 Gy. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.
Resumo:
The walkeriana species-group of iridescent Euhesma bees is described with the following nine species considered new: E. allunga, E. banksia, E. bronzus, E. dongara, E. lobata, E. spinola, E. sybilae, E. viridescens and E. xana. Two new synonymies are proposed: E. mica (Cockerell) with E. neglectula (Cockerell), and E. halictoides (Rayment) with E. latissima (Cockerell). A key enables the separation of species, and distributions are mapped.
Resumo:
Purpose: To assess the toxicity and the efficacy of preoperative radiotherapy with continuous infusion 5-fluorouracil (5-FU) for locally advanced adenocarcinoma of the rectum. Methods and Materials: Eligible patients had newly diagnosed localized adenocarcinoma of the rectum within 12 cm of the anal verge, Stage T3-4, and were suitable for curative resection. Eighty-two patients were treated with radiotherapy-50.4 Gy in 28 fractions in 5.6 weeks, given concurrently with continuous infusion 5-FU, using either 96-h/week infusion at 300 mg/m(2)/day or 7-days/week infusion at 225 mg/m(2)/day. Results: The median age was 59 years (range, 27-87), and 67% of patients were male. Pretreatment stages of the rectal cancer were T3, 89% and resectable T4, 11%, with endorectal ultrasound confirmation in 67% of patients. Grade 3 acute toxicity occurred in 5 of 82 patients (6%; 95% confidence interval [CI], 2-14%). Types of surgical resection were anterior resection, 61%; abdominoperineal resection, 35%; and other procedures, 4%. There was no operative mortality. Anastomotic leakage after low anterior resection occurred in 3 of 50 patients (6%; 95% CI, 1-17%). The pathologic complete response rate was 16% (95% CI, 9-26%). Pathologic Stages T2 or less occurred in 51%. Conclusion: Preoperative radiotherapy with continuous infusion 5-FU for locally advanced rectal cancer is a safe regimen, with a significant downstaging effect. It does not seem to lead to a significant increase in serious surgical complications. (C) 2001 Elsevier Science Inc.
Resumo:
Rheumatic fever (RF)/rheumatic heart disease (RHD) and post-streptococcal glomerulonephritis are thought to be autoimmune diseases, and follow group A streptococcal (GAS) infection. Different GAS M types have been associated with rheumatogenicity or nephritogenicity and categorized into either of two distinct classes (I or II) based on amino acid sequences present within the repeat region ('C' repeats) of the M protein. Sera from ARF patients have previously been shown to contain elevated levels of antibodies to the class I-specific epitope and myosin with the class I-specific antibodies also being cross-reactive to myosin, suggesting a disease association. This study shows that immunoreactivity of the class I-specific peptide and myosin does not differ between controls and acute RF (ARF)/RHD in populations that are highly endemic for GAS, raising the possibility that the association is related to GAS exposure, not the presence of ARF/RHD. Peptide inhibition studies suggest that the class I epitope may be conformational and residue 10 of the peptide is critical for antibody binding. We demonstrate that correlation of antibody levels between the class I and II epitope is due to class II-specific antibodies recognizing a common epitope with class I which is contained within the sequence RDL-ASRE. Our results suggest that antibody prevalence to class I and II epitopes and myosin is associated with GAS exposure, and that antibodies to these epitopes are not an indicator of disease nor a pathogenic factor in endemic populations.
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Although the malaria parasite was discovered more than 120 years ago, it is only during the past 20 years, following the cloning of malaria genes, that we have been able to think rationally about vaccine design and development. Effective vaccines for malaria could interrupt the life cycle of the parasite at different stages in the human host or in the mosquito. The purpose of this review is to outline the challenges we face in developing a vaccine that will limit growth of the parasite during the stage within red blood cells - the stage responsible for all the symptoms and pathology of malaria. More than 15 vaccine trials have either been completed or are in progress, and many more are planned. Success in current trials could lead to a vaccine capable of saving more than 2 million lives per year.
Resumo:
Background: The International Child Care Practices Study (ICCPS) has collected descriptive data from 21 centres in 17 countries. In this report, data are presented on the infant sleeping environment with the main focus being sudden infant death syndrome (SIDS) risk factors (bedsharing and infant using a pillow) and protective factors (infant sharing a room with adult) that are not yet well established in the literature. Methods: Using a standardised protocol, parents of infants were surveyed at birth by interview and at 3 months of age mainly by postal questionnaire. Centres were grouped according to geographic location. Also indicated was the level of SIDS awareness in the community, i.e. whether any campaigns or messages to “reduce the risks of SIDS” were available at the time of the survey. Results: Birth interview data were available for 5488 individual families and 4656 (85%) returned questionnaires at 3 months. Rates of bedsharing varied considerably (2–88%) and it appeared to be more common in the samples with a lower awareness of SIDS, but not necessarily a high SIDS rate. Countries with higher rates of bedsharing appeared to have a greater proportion of infants bedsharing for a longer duration (>5 h). Rates of room sharing varied (58–100%) with some of the lowest rates noted in centres with a higher awareness of SIDS. Rates of pillow use ranged from 4% to 95%. Conclusions: It is likely that methods of bedsharing differ cross-culturally, and although further details were sought on different bedsharing practices, it was not possible to build up a composite picture of “typical” bedsharing practices in these different communities. These data highlight interesting patterns in child care in these diverse populations. Although these results should not be used to imply that any particular child care practice either increases or decreases the risk of SIDS, these findings should help to inject caution into the process of developing SIDS prevention campaigns for non-Western cultures.
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Objectives: To assess the accuracy of reporting from both a diet history and food record and identify some of the characteristics of more accurate reporters in a group of healthy adult volunteers for an energy balance study. Design: Prospective measurements in free-living people. Setting: Wollongong, Australia. Subjects: Fifteen healthy volunteers (seven male, eight female; aged 22 -59 y; body mass index (BMI) 19 - 33 kg/m(2)) from the local community in the city of Wollongong, Australia. Interventions: Measurement of energy intake via diet history interview and 7 day food records, total energy expenditure by the doubly labelled water technique over 14 days, physical activity by questionnaire, and body fat by dual-energy X-ray absorptiometry. Results: Increased misreporting of energy intake was associated with increased energy expenditure (r = 0.90, P < 0.0001, diet history; r(s)=0.79, P=0.0005, food records) but was not associated with age, sex, BMI or body fat. Range in number of recorded dinner foods correlated positively with energy expenditure (r(s)=0.63, P=0.01) and degree of misreporting (r(s)=0.71, P=0.003, diet history; r(s)=0.63, P=0.01, food records). Variation in energy intake at dinner and over the whole day identified by the food records correlated positively with energy expenditure (r=0.58, P = 0.02) and misreporting on the diet history (r=0.62, P=0.01). Conclusions: Subjects who are highly active or who have variable dietary and exercise behaviour may be less accurate in reporting dietary intake. Our findings indicate that it may be necessary to screen for these characteristics in studies where accuracy of reporting at an individual level is critical. Sponsorship: The study was supported in part by Australian Research Council funds made available through the University of Wollongong.
Resumo:
The Australian species of Allomethus and Claraeola are revised and include one described species, Claraeola erinys (Perkins), and five new species: Allomethus unicicolis sp. n., Claraeola cyclohirta sp. n., C. sicilis sp. n., C. spargosis sp. n., and C. yingka sp. n.. Claraeola hylaea (Perkins) is proposed to be a synonym of C. erinys (Perkins). A key to species is provided and male and female genitalia are illustrated. The Australian species are placed phylogenetically into a world context using available taxa within the Allomethus genus group. The phylogenetic relationships are discussed in light of a cladistic analysis involving 22 taxa and 60 characters.
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Cliff-nesting pale-winged starlings (Onychognathus nabouroup) gather on the cliff tops to perform Group Displays which include both aggressive and courtship elements: Hopping, Wing Stretching, Wing Drooping, Wing Flicking, Staring, Head Forward Threat and Butterfly Fluttering. These displays occur throughout the year, most frequently in the late afternoon. We suggest that this behaviour may be important in pair formation, and in establishing dominance relationships between birds breeding at the same site.
Resumo:
Image : To assess the potential for sucralfate administered rectally to reduce the risk of late rectal morbidity in patients undergoing nonconformal radiotherapy (RT) for carcinoma of the prostate and to study the variables potentially contributing to late rectal morbidity and particularly to explore the relationship between acute and late toxicity. Image : Eighty-six patients with localized prostate carcinoma were randomized in a double-blind, placebo-controlled study to a daily enema of 3 g of sucralfate in a 15-mL suspension or the same suspension without sucralfate. The enema began the first day of RT and was continued for 2 weeks after treatment completion. The primary end point of the study was acute Radiation Therapy Oncology Group (RTOG)/European Organization for Research and Treatment of Cancer (EORTC) toxicity; however, the patients were followed for an additional 5 years on a 6-month basis. The evaluation included late RTOG/EORTC toxicity and a patient self-assessment questionnaire. Image : With a median follow-up of 5 years, the Kaplan-Meier probability of late Grade 2 RTOG/EORTC toxicity was 12% (95% confidence interval [CI] 2–22%) for placebo and 5% (95% CI 0–12%) for sucralfate (p = 0.26). The probability of late rectal bleeding was 59% (95% CI 45–73%) for placebo and 54% (95% CI 40–68%) for sucralfate. No statistically significant difference was found between the treatment arms for the peak incidence of any of the other patient self-assessment variables. Cox proportional hazards modeling indicated acute RTOG/EORTC toxicity of Grade 2 or greater was associated with a hazard ratio of 2.74 (95% CI 1.31–5.73) for the development of late toxicity of Grade 1 or greater. Substituting the patient self-assessment variables for acute RTOG/EORTC toxicity revealed that rectal pain of a moderate or severe grade during RT was the best predictor of the subsequent development of late toxicity, with a hazard ratio of 3.44 (95% CI 1.68–7). Image : The results of this study do not support the use of sucralfate administered rectally as a method for reducing the late toxicity of nonconformal RT for prostate cancer. There appears to be an association between the development of acute and subsequent late toxicity, although the nature of this association remains to be determined
Resumo:
Many of the asexual stage Plasmodium falciparum proteins that are the targets of host protective responses are markedly polymorphic. The full repertoire of diversity is not defined for any antigen. Most studies have focused on the genes encoding merozoite surface proteins 1 and 2 (MSP1, MSP2). We explored the extent of diversity of some of the less studied merozoite surface antigens and analyzed the degree of complexity of malaria field isolates by deriving nucleotide sequences of several antigens. We have determined the genotype of apical membrane antigen 1 (AMA1) in a group of 30 field samples, collected over 29 months, from individuals living in an area of intense malaria transmission in Irian Jaya, identifying 14 different alleles. AMA1 genotyping was combined with previously determined MSP2 typing. AMA1 had the greatest power in distinguishing between isolates but methodological problems, especially when mixed infections are present, suggest it is not an ideal typing target. MSP1, MSP3, and glutamate-rich protein genotypes were also determined from a smaller group of samples, and all results were combined to derive an extended antigenic haplotype. Within this subset of 10 patients, nine different genotypes could be discerned; however, five patients were all infected with the same strain. This strain was present in individuals from two separate villages and was still present 12 months later. This strain was predominant at the first time point but had disappeared at the fourth time point. This significant change in malaria genotypes could be due to strain-specific immunity developing in this population.